_:b369426011 . _:b369426010 . . . _:b369426021 . . _:b369426002 . _:b3097187 "Another possibility is combined PI3K/mTOR blockade to prevent rapamyin-induced activation of Akt caused by loss of negative feedback [27,>>28<<]. The time-to-progression analysis in our study suggests that the prognosis of these patients is worse, therefore inhibitors that act upstream of Akt may be useful to prevent this complication. Indeed, one dual PI3K/mTOR inhibitor has" . _:b369426020 . . . _:b369426023 . _:b369426022 . _:b369425994 . _:b369426017 . _:b369426016 . _:b369426246 . _:b369426019 . _:b3097165 "Overall, our data set showed many chromosomal aberrations typically found in glioblastoma [>>34<<], including frequent gains of chromosome 7, loss of chromosome 10, and focal amplifications of EGFR, PDGFRA, CDK4, and MDM2 (Figure S5)." . _:b369426018 . _:b369426029 . _:b369426385 . _:b369426192 . _:b369426028 . _:b369426394 . . _:b369426031 . . . . _:b369426030 . _:b3097181 "with mechanisms of resistance to other kinase inhibitors (in chronic myeloid leukemia, gastrointestinal stromal tumors, and EGFR-dependent lung cancer), which often occurs through point mutations in the kinase target in tumor cells [>>43<<] and raises the possibility that a larger fraction of PTEN null glioblastomas could be rapamycin-sensitive if more significant mTOR inhibition could be achieved." . _:b369426025 . _:b369426405 . . _:b369426024 . _:b369426027 . _:b369426001 . _:b369426026 . _:b369426128 . _:b369426233 . _:b369426052 . _:b369426037 . . _:b369426036 . _:b369426278 . _:b369426039 . _:b369426038 . _:b369426318 . . _:b369426033 . _:b369425964 . _:b369426032 . _:b369426013 . _:b369426346 . _:b369426439 . . _:b369426035 . _:b369426193 . _:b369426034 . _:b369426045 . . _:b369426044 . _:b369426047 . _:b369426046 . . . _:b369426041 . . . _:b369426040 . _:b369426186 . _:b369426043 . _:b369426042 . _:b369426267 . _:b369426053 . _:b369426052 . _:b369426055 . _:b369426379 . _:b369426184 . _:b369426054 . _:b369426049 . _:b369426382 . . _:b369426048 . _:b369426051 . . _:b369426050 . _:b369426414 . _:b369426061 . _:b3097139 . . _:b369426060 . _:b369426457 . _:b369426063 . _:b369426062 . _:b369426057 . _:b369426056 . _:b369426133 . _:b369426473 . . _:b369426059 . _:b369426058 . _:b3097179 "that affect mTOR dependence of tumor cells [>>38<<,42]. The surprising finding in this trial is that despite using doses of rapamycin sufficient to give low nM intratumoral levels, such doses do not translate into mTOR inhibition in all patients." . _:b369426134 . _:b369426069 . _:b369426383 . _:b369425982 . _:b369426068 . . _:b369426071 . _:b369426119 . _:b369426070 . _:b369426065 . _:b369426063 . _:b369426064 . . . _:b369426067 . _:b369426190 . . _:b369426066 . _:b369426407 . _:b369426374 . _:b369426077 . _:b369426076 . . _:b369426079 . . _:b369426078 . . _:b369426073 . _:b369426072 . _:b369426075 . _:b369426074 . . . _:b369426085 . _:b369426084 . _:b369426087 . _:b369426086 . _:b369426165 . _:b369426081 . _:b369426080 . . . . _:b369426083 . _:b3097191 . _:b369426082 . . _:b369426093 . _:b3097173 . _:b369426092 . _:b369426095 . _:b369425992 . _:b369426094 . _:b369426150 . _:b369426089 . _:b369426088 . _:b369426091 . . _:b369426485 . _:b369426281 . _:b369426090 . _:b369426470 . _:b369426101 . _:b369426462 . _:b369426100 . _:b369426103 . _:b369426102 . _:b369426097 . _:b369426082 . _:b369426348 . _:b369426096 . _:b369426099 . _:b369426098 . _:b369426093 . _:b369426319 . _:b369426109 . . _:b369426442 . _:b369426108 . _:b369426111 . _:b3097146 . _:b369426110 . _:b3097160 "mTOR inhibition by rapamycin can cancel this negative feedback and activate Akt in some cancer cell lines and tumor samples, but the potential clinical impact is unknown [8,>>27<<,28]. We assessed Akt activity in S1 and S2 samples in the rapamycin-treated patients using phosphosite-specific antibodies against the serine/threonine kinase Akt (serine 473) and its downstream substrate PRAS 40 (threonine 246), which" . _:b369426105 . _:b369426456 . _:b369426104 . . _:b369426107 . _:b369426106 . _:b369426391 . . _:b369426117 . . _:b369426116 . _:b369426119 . _:b369426118 . _:b369426294 . . _:b369426183 . _:b369426113 . _:b369426112 . . _:b369426115 . . _:b369426114 . _:b369426017 . . _:b369426125 . _:b369426078 . _:b369426124 . _:b369425959 "13"^^ . _:b3097139 . . . _:b369426127 . _:b369425955 "20"^^ . _:b369426126 . _:b369425974 . _:b369426121 . _:b3097149 . . _:b369425957 "18"^^ . . _:b369426118 . _:b369426120 . . _:b369425956 "19"^^ . _:b369426123 . _:b369426291 . _:b369425958 "14"^^ . _:b369426122 . . . _:b369426424 . _:b369426133 . _:b369426132 . _:b3097170 . _:b369425966 "9"^^ . _:b369426135 . _:b369426087 . _:b369425967 "9"^^ . _:b369426134 . _:b369425988 . _:b369425964 "11"^^ . _:b369426129 . _:b369426343 . _:b369425965 "9"^^ . _:b369426169 . _:b369425963 "11"^^ . _:b369426128 . . _:b369425962 "12"^^ . _:b369426131 . _:b369426171 . _:b369425961 "12"^^ . _:b369426130 . _:b369426100 . . _:b369426349 . _:b369425960 "12"^^ . _:b369426141 . _:b369425974 "8"^^ . _:b369426140 . . _:b369426389 . _:b369425975 "8"^^ . _:b369426143 . . _:b369426142 . _:b369425972 "9"^^ . _:b3097148 "results" . _:b3097162 . _:b369426137 . _:b369425973 "8"^^ . . _:b369426136 . _:b369425970 "9"^^ . . _:b369426139 . _:b369425971 "9"^^ . . _:b369426138 . _:b369425968 "9"^^ . . _:b369426027 . _:b369426149 . _:b369425969 "9"^^ . _:b369425982 "6"^^ . _:b369426148 . _:b369425983 "6"^^ . _:b3097168 . _:b369426151 . _:b369426256 . _:b369426006 . _:b369425980 "7"^^ . _:b369426150 . . _:b3097183 "In the short term, it may be possible to identify the early Ki-67 responders using PET tracers such as 3\u2032-deoxy-3\u2032-18F-fluorothymidine (FLT) that can read out proliferation noninvasively [>>45<<]. Although such identification would not itself improve rapamycin delivery to the tumor cells, it could at least identify the subset of tumors in which rapamycin delivery appears to be problematic. Success here would also obviate the need" . _:b369426158 . _:b369425981 "7"^^ . . _:b369426145 . _:b3097174 "As predicted from preclinical studies [>>27<<,28], rapamycin also led to the activation of Akt in some cases, and this activation was significantly correlated with shorter time-to-tumor progression." . _:b369425978 "7"^^ . _:b369426339 . _:b369426144 . _:b369425979 "7"^^ . _:b369426147 . _:b369426094 . . _:b369425976 "8"^^ . _:b369426146 . _:b369425977 "8"^^ . _:b369426157 . _:b369426357 . _:b369426506 . _:b369426380 . _:b369426156 . _:b369425989 "5"^^ . _:b369426159 . _:b369425988 "6"^^ . _:b369426284 . _:b369426158 . _:b369425991 "5"^^ . . _:b369426153 . _:b369425990 "5"^^ . _:b369425986 "6"^^ . _:b369426152 . _:b3097146 . _:b369426386 . _:b369425987 "6"^^ . _:b369426155 . _:b369425984 "6"^^ . _:b369426039 . _:b369426154 . _:b369425985 "6"^^ . . _:b369426165 . . _:b369426164 . . _:b369425997 "5"^^ . . _:b369426167 . _:b369425996 "5"^^ . _:b369426166 . _:b369426000 . _:b369425999 "5"^^ . _:b369426161 . _:b369425998 "5"^^ . _:b369426427 . _:b369426454 . _:b369426160 . _:b369425993 "5"^^ . _:b3097173 . _:b369426163 . _:b369426054 . _:b369425992 "5"^^ . _:b369426162 . _:b369425995 "5"^^ . _:b369426173 . _:b369425994 "5"^^ . . _:b369426005 "4"^^ . _:b369426172 . _:b369426175 . _:b369426004 "5"^^ . _:b3097144 . _:b369426007 "4"^^ . _:b369426174 . . _:b369426006 "4"^^ . _:b369426169 . . _:b369426347 . _:b369426168 . . _:b369426001 "5"^^ . _:b369426480 . _:b369426154 . _:b369426171 . _:b369426000 "5"^^ . _:b369426170 . _:b369426003 "5"^^ . _:b369426208 . . _:b369426002 "5"^^ . _:b369426011 . _:b369426013 "4"^^ . _:b369426404 . _:b369426012 "4"^^ . _:b3097152 . _:b369426015 "4"^^ . _:b3097147 . . _:b369426014 "4"^^ . . _:b3097173 "The goal of this study was to evaluate directly rapamycin in patients whose tumors have defects in PTEN, based on preclinical findings originally generated by our group and others showing mTOR dependence in such models [>>9<<\u201315]. In designing the clinical experiment, we sought to validate the use of a PTEN assay for patient selection, document mTOR inhibition in tumor tissue (of particular importance for brain cancers), and gain preliminary evidence of" . _:b369426135 . _:b369426009 "4"^^ . _:b369426008 "4"^^ . . _:b369426011 "4"^^ . . . _:b369426435 . _:b369426010 "4"^^ . _:b369426313 . . _:b369426021 "4"^^ . _:b369426020 "4"^^ . . _:b369426023 "4"^^ . . . _:b369426022 "4"^^ . _:b369426017 "4"^^ . _:b369426102 . _:b369426016 "4"^^ . . _:b369426019 "4"^^ . _:b369426272 . _:b369426018 "4"^^ . _:b369426038 . . _:b369426029 "4"^^ . _:b369426028 "4"^^ . . _:b369426031 "4"^^ . _:b369426287 . _:b369426030 "4"^^ . _:b369426025 "4"^^ . _:b3097157 "One possibility, based on the fact that rapamycin is sequestered in red blood cells [>>22<<], is that the high intratumoral concentrations of rapamycin observed in these resistant patients reflect red cell pooling in highly vascular tumors." . _:b369426024 "4"^^ . _:b369426045 . _:b369426027 "4"^^ . . _:b369426026 "4"^^ . _:b369426037 "4"^^ . _:b369426036 "4"^^ . _:b369426064 . . _:b369426039 "4"^^ . _:b369426038 "4"^^ . _:b369426338 . _:b3097173 . _:b369426033 "4"^^ . _:b369426083 . _:b369426251 . _:b369426032 "4"^^ . _:b369426505 . . _:b369426035 "4"^^ . . _:b3097172 "great promise as anticancer drugs in a spectrum of preclinical models, but it has been difficult to demonstrate convincing clinical activity in single-agent trials using conventional radiographic and clinical criteria for response [>>38<<]. Potential explanations include the largely cytostatic action of these drugs in the laboratory, uncertainty over dose and schedule, and lack of studies to evaluate the drug in subsets of patients most likely to respond based on molecular" . _:b369426034 "4"^^ . _:b369426077 . _:b369426211 . _:b369426045 "3"^^ . _:b369426044 "3"^^ . _:b369426047 "3"^^ . _:b369426046 "3"^^ . _:b369426437 . . _:b369426041 "4"^^ . _:b369426040 "4"^^ . _:b369426043 "3"^^ . _:b369426213 . _:b369426042 "3"^^ . . _:b369426053 "3"^^ . _:b369426052 "3"^^ . _:b369426055 "3"^^ . _:b369426054 "3"^^ . _:b369426049 "3"^^ . _:b3097159 . _:b369426048 "3"^^ . . _:b369426235 . . _:b369426051 "3"^^ . . . _:b369426050 "3"^^ . . . _:b369426061 "3"^^ . . _:b369426060 "3"^^ . _:b369426063 "3"^^ . . . _:b369425985 . _:b369426062 "3"^^ . _:b369426057 "3"^^ . . _:b369426056 "3"^^ . _:b369426464 . . _:b369426059 "3"^^ . _:b369426058 "3"^^ . _:b369426031 . _:b369426069 "3"^^ . . _:b369426068 "3"^^ . . _:b369426071 "3"^^ . . . _:b369426070 "3"^^ . _:b369426065 "3"^^ . _:b369425966 . _:b369426064 "3"^^ . _:b369426067 "3"^^ . . . _:b369426066 "3"^^ . . . _:b369426395 . _:b369426077 "3"^^ . . _:b369426076 "3"^^ . . _:b369426079 "3"^^ . . _:b369426078 "3"^^ . _:b369426377 . _:b369426073 "3"^^ . . _:b369426072 "3"^^ . . _:b369426075 "3"^^ . . _:b369426074 "3"^^ . . . _:b369426085 "3"^^ . . _:b369426084 "3"^^ . _:b369425970 . _:b369426087 "3"^^ . _:b369426086 "3"^^ . _:b369426437 "2"^^ . . . _:b369426081 "3"^^ . _:b369426436 "2"^^ . _:b369426080 "3"^^ . _:b369426439 "2"^^ . _:b369426219 . _:b369426083 "3"^^ . _:b369426438 "2"^^ . . _:b369426082 "3"^^ . _:b369426433 "2"^^ . _:b369426255 . _:b369426160 . _:b369426432 "2"^^ . _:b369426093 "3"^^ . _:b369426092 "3"^^ . _:b369426435 "2"^^ . . _:b369426095 "3"^^ . _:b369426434 "2"^^ . . . _:b369426094 "3"^^ . _:b369426445 "2"^^ . . _:b3097180 "that affect mTOR dependence of tumor cells [38,>>42<<]. The surprising finding in this trial is that despite using doses of rapamycin sufficient to give low nM intratumoral levels, such doses do not translate into mTOR inhibition in all patients." . . _:b369426444 "2"^^ . _:b369426089 "3"^^ . _:b369426088 "3"^^ . _:b369426447 "2"^^ . _:b369426161 . _:b369426091 "3"^^ . _:b369426446 "2"^^ . _:b369426090 "3"^^ . _:b369426441 "2"^^ . . _:b3097146 . _:b369426340 . _:b369426440 "2"^^ . _:b369426101 "3"^^ . _:b3097158 . _:b369426100 "3"^^ . _:b369426443 "2"^^ . _:b369426103 "3"^^ . _:b369426442 "2"^^ . _:b369426102 "3"^^ . _:b369426453 "2"^^ . . . _:b369426097 "3"^^ . _:b369426452 "2"^^ . _:b369426358 . _:b369426455 "2"^^ . _:b369426096 "3"^^ . _:b369426099 "3"^^ . _:b369426454 "2"^^ . _:b369426098 "3"^^ . _:b369426449 "2"^^ . . _:b369426496 . _:b3097186 . _:b369426109 "3"^^ . _:b369426448 "2"^^ . _:b369426108 "3"^^ . _:b369426451 "2"^^ . _:b369426221 . _:b369426111 "3"^^ . _:b369426450 "2"^^ . _:b369426110 "3"^^ . _:b369426461 "2"^^ . _:b369426330 . _:b369426105 "3"^^ . _:b369426460 "2"^^ . _:b369426477 . . _:b369426463 "2"^^ . _:b369426104 "3"^^ . _:b369426462 "2"^^ . _:b369426107 "3"^^ . _:b369426457 "2"^^ . _:b369426106 "3"^^ . _:b369426456 "2"^^ . _:b369426117 "3"^^ . . _:b369426188 . _:b369426459 "2"^^ . _:b369426116 "3"^^ . _:b369426458 "2"^^ . _:b369426119 "3"^^ . _:b369426469 "2"^^ . _:b369426118 "3"^^ . _:b369426468 "2"^^ . _:b369426113 "3"^^ . _:b369426460 . . _:b369426471 "2"^^ . _:b369426112 "3"^^ . _:b369426470 "2"^^ . _:b369426115 "3"^^ . . _:b369426465 "2"^^ . _:b369426114 "3"^^ . _:b369426048 . _:b369426464 "2"^^ . _:b369426125 "3"^^ . _:b369426467 "2"^^ . _:b369426124 "3"^^ . _:b369426127 "2"^^ . . _:b369426466 "2"^^ . _:b369426376 . . . _:b369426126 "2"^^ . _:b369426477 "2"^^ . _:b369426476 "2"^^ . . _:b369426121 "3"^^ . . _:b369426399 . _:b369426479 "2"^^ . _:b369426120 "3"^^ . _:b369426364 . _:b369426136 . _:b369426478 "2"^^ . _:b369426123 "3"^^ . . _:b369426473 "2"^^ . _:b369426122 "3"^^ . _:b369426071 . _:b369426419 . _:b369426133 "2"^^ . _:b369426472 "2"^^ . _:b369426182 . _:b369426132 "2"^^ . _:b369426475 "2"^^ . . _:b369426135 "2"^^ . _:b369426474 "2"^^ . _:b369426134 "2"^^ . _:b369426485 "2"^^ . . . _:b369426129 "2"^^ . _:b3097176 . _:b369426484 "2"^^ . _:b369426315 . _:b369426059 . _:b369426128 "2"^^ . _:b369426487 "2"^^ . . _:b369426131 "2"^^ . _:b369426486 "2"^^ . . _:b369426130 "2"^^ . _:b369426431 . _:b369426481 "2"^^ . _:b369426187 . _:b369426141 "2"^^ . _:b369426480 "2"^^ . _:b369426242 . _:b369426140 "2"^^ . _:b369426483 "2"^^ . _:b369426143 "2"^^ . _:b369426482 "2"^^ . _:b369426266 . _:b369426142 "2"^^ . _:b369426493 "2"^^ . _:b369426459 . _:b3097161 . . _:b369426137 "2"^^ . _:b369426492 "2"^^ . . _:b369426136 "2"^^ . _:b369426495 "2"^^ . _:b3097160 . _:b369426139 "2"^^ . . _:b369426494 "2"^^ . _:b369426286 . _:b369426138 "2"^^ . _:b369426489 "2"^^ . . . _:b369426149 "2"^^ . _:b369426488 "2"^^ . _:b369426467 . _:b369426148 "2"^^ . _:b369426061 . _:b3097175 . _:b369426491 "2"^^ . _:b369426151 "2"^^ . _:b369426490 "2"^^ . _:b369426150 "2"^^ . _:b369426501 "2"^^ . _:b369426116 . _:b369426145 "2"^^ . _:b369426500 "2"^^ . _:b369426144 "2"^^ . _:b369426503 "2"^^ . . . _:b3097151 . . . _:b369426147 "2"^^ . _:b369426502 "2"^^ . _:b369426146 "2"^^ . _:b369426497 "2"^^ . _:b3097145 . _:b369426057 . _:b369426157 "2"^^ . _:b369426496 "2"^^ . _:b369426283 . _:b369426156 "2"^^ . _:b369426499 "2"^^ . _:b369426471 . . _:b369426159 "2"^^ . _:b369426498 "2"^^ . _:b3097146 . _:b369425958 . _:b369426158 "2"^^ . _:b369426092 . _:b369426153 "2"^^ . _:b3097174 . . _:b369426152 "2"^^ . _:b369426453 . _:b369426155 "2"^^ . . . _:b369426154 "2"^^ . _:b369426505 "2"^^ . _:b369426165 "2"^^ . _:b369426504 "2"^^ . . _:b3097161 "mTOR inhibition by rapamycin can cancel this negative feedback and activate Akt in some cancer cell lines and tumor samples, but the potential clinical impact is unknown [8,27,>>28<<]. We assessed Akt activity in S1 and S2 samples in the rapamycin-treated patients using phosphosite-specific antibodies against the serine/threonine kinase Akt (serine 473) and its downstream substrate PRAS 40 (threonine 246), which" . . . _:b369426132 . _:b369426164 "2"^^ . _:b369426257 . _:b369426450 . _:b369425990 . _:b369426167 "2"^^ . _:b369426506 "2"^^ . _:b369426166 "2"^^ . . _:b369426161 "2"^^ . _:b369426239 . _:b369426160 "2"^^ . _:b3097187 . _:b369426163 "2"^^ . . _:b369426162 "2"^^ . _:b3097186 "Another possibility is combined PI3K/mTOR blockade to prevent rapamyin-induced activation of Akt caused by loss of negative feedback [>>27<<,28]. The time-to-progression analysis in our study suggests that the prognosis of these patients is worse, therefore inhibitors that act upstream of Akt may be useful to prevent this complication. Indeed, one dual PI3K/mTOR inhibitor has" . . . _:b369426173 "2"^^ . . _:b369426172 "2"^^ . _:b369426130 . . . _:b369426175 "2"^^ . _:b369426058 . _:b369426174 "2"^^ . _:b3097173 . _:b3097173 . _:b369426474 . _:b369426169 "2"^^ . _:b369425989 . _:b3097158 . _:b369426304 . _:b369426168 "2"^^ . _:b369426033 . _:b369426021 . _:b369426401 . _:b369426171 "2"^^ . _:b369426170 "2"^^ . _:b369426181 "2"^^ . . _:b369426180 "2"^^ . _:b369426117 . _:b369426183 "2"^^ . . _:b369426182 "2"^^ . _:b369426177 "2"^^ . _:b369426176 "2"^^ . . _:b369426307 . _:b369426179 "2"^^ . . . _:b369426178 "2"^^ . . _:b369426189 "2"^^ . _:b369426074 . _:b369426188 "2"^^ . _:b369426411 . _:b369426486 . _:b369426191 "2"^^ . _:b369426190 "2"^^ . . . _:b369426185 "2"^^ . _:b369426184 "2"^^ . _:b369426187 "2"^^ . _:b369426186 "2"^^ . . _:b369426298 . _:b369426197 "2"^^ . . _:b369426196 "2"^^ . _:b369426479 . _:b369426067 . _:b369426199 "2"^^ . _:b369426198 "2"^^ . _:b369426455 . . _:b369426193 "2"^^ . _:b369426390 . _:b369426192 "2"^^ . _:b369426195 "2"^^ . _:b369426112 . _:b369426194 "2"^^ . _:b369426051 . _:b369426205 "2"^^ . . _:b369426204 "2"^^ . _:b369426224 . _:b369426207 "2"^^ . _:b369426206 "2"^^ . _:b369426201 "2"^^ . . _:b369426200 "2"^^ . _:b369426203 "2"^^ . _:b369426202 "2"^^ . . . _:b369426498 . _:b3097184 . _:b369426213 "2"^^ . _:b369426451 . _:b369426212 "2"^^ . _:b369426075 . _:b369426215 "2"^^ . _:b369426214 "2"^^ . _:b369426209 "2"^^ . _:b369426212 . _:b369426208 "2"^^ . _:b369426211 "2"^^ . _:b369426210 "2"^^ . . _:b369426221 "2"^^ . _:b369426220 "2"^^ . _:b369426223 "2"^^ . _:b369426222 "2"^^ . _:b369426217 "2"^^ . _:b369425986 . _:b369426216 "2"^^ . _:b369426219 "2"^^ . . _:b369426218 "2"^^ . _:b3097190 . _:b369426229 "2"^^ . _:b369426191 . . _:b3097169 . _:b369426228 "2"^^ . _:b369426231 "2"^^ . _:b369426230 "2"^^ . . _:b369426225 "2"^^ . _:b369426247 . . _:b369426224 "2"^^ . _:b369426310 . _:b369426227 "2"^^ . . . _:b3097168 "Although eligibility was determined on the basis of a semiquantitive manual PTEN score [>>17<<,18], we later refined our PTEN scoring methodology by using digital image quantification software." . _:b369426434 . _:b369426226 "2"^^ . . _:b369426363 . _:b369426091 . _:b369426237 "2"^^ . . . _:b369426236 "2"^^ . _:b369426249 . _:b369426239 "2"^^ . _:b369426238 "2"^^ . _:b369426420 . . _:b369426233 "2"^^ . . . _:b369426232 "2"^^ . _:b369426235 "2"^^ . _:b369426234 "2"^^ . _:b369426245 "2"^^ . . _:b369426440 . _:b369426244 "2"^^ . _:b369426247 "2"^^ . _:b369426019 . . _:b369426246 "2"^^ . _:b3097167 "Furthermore, PDGFR is an additional target of mTOR negative feedback which can be overcome by enhanced PDGFR\u03B2 expression [>>36<<]." . _:b369426241 "2"^^ . . _:b3097178 "patients were not evaluated prospectively for PTEN status (no molecular selection criteria), and CCI-779 was delivered weekly rather than daily based on a phase I experience that defined a maximum tolerated dose using this schedule [40,>>41<<]. In light of our findings about the magnitude of mTOR inhibition required for response (discussed below), this schedule raises concerns about the presumed lack of target coverage during nontreatment days." . _:b369426240 "2"^^ . _:b369426344 . _:b369426243 "2"^^ . _:b369426242 "2"^^ . _:b369426476 . _:b369426253 "2"^^ . _:b369426252 "2"^^ . _:b3097162 "PRAS40 has also been recently shown to inhibit mTOR, and this inhibition is relieved by Akt phosphorylation [>>29<<\u201331]. Seven of 14 (50%) patients had a statistically significant (p < 0.05, Wilcoxon test) increase in PRAS40 phosphorylation in their S2 sample (Figure 4B). Of note, one patient (11) had a significant decrease in PRAS40 phosphorylation" . . _:b369426255 "2"^^ . _:b369425993 . . _:b369426254 "2"^^ . _:b369426249 "2"^^ . _:b369426248 "2"^^ . . _:b369426199 . . _:b369426251 "2"^^ . _:b369426250 "2"^^ . _:b369426176 . _:b369426261 "2"^^ . _:b369426260 "2"^^ . _:b369426263 "2"^^ . _:b369426043 . _:b369426262 "2"^^ . _:b369426257 "2"^^ . . _:b369426256 "2"^^ . . _:b369426259 "2"^^ . _:b369426258 "2"^^ . _:b369426269 "2"^^ . _:b369426240 . _:b369426268 "2"^^ . . _:b3097150 . _:b369426271 "2"^^ . _:b369426270 "2"^^ . . _:b369426265 "2"^^ . _:b369426264 "2"^^ . _:b369426267 "2"^^ . _:b369426214 . _:b369426266 "2"^^ . _:b369426277 "2"^^ . . _:b369426276 "2"^^ . _:b369426279 "2"^^ . _:b369426278 "2"^^ . _:b369426029 . . _:b369426041 . _:b369426273 "2"^^ . _:b369426400 . _:b369426272 "2"^^ . . _:b369426275 "2"^^ . _:b369426206 . _:b369426274 "2"^^ . _:b369426285 "2"^^ . _:b369426284 "2"^^ . _:b369426287 "2"^^ . _:b3097146 . _:b369426286 "2"^^ . _:b369426418 . . _:b369426281 "2"^^ . _:b369426280 "2"^^ . . _:b369426283 "2"^^ . _:b369426053 . _:b369426503 . _:b369426282 "2"^^ . . _:b369426131 . _:b369426293 "2"^^ . . _:b369426259 . _:b3097159 "mTOR inhibition by rapamycin can cancel this negative feedback and activate Akt in some cancer cell lines and tumor samples, but the potential clinical impact is unknown [>>8<<,27,28]. We assessed Akt activity in S1 and S2 samples in the rapamycin-treated patients using phosphosite-specific antibodies against the serine/threonine kinase Akt (serine 473) and its downstream substrate PRAS 40 (threonine 246), which" . _:b369426292 "2"^^ . _:b369426295 "2"^^ . . . . _:b369426294 "2"^^ . . _:b369426289 "2"^^ . _:b369426288 "2"^^ . _:b369425961 . _:b369426291 "2"^^ . _:b3097171 . . _:b3097169 "Although eligibility was determined on the basis of a semiquantitive manual PTEN score [17,>>18<<], we later refined our PTEN scoring methodology by using digital image quantification software." . _:b369426290 "2"^^ . . _:b369426492 . _:b369426301 "2"^^ . _:b369426300 "2"^^ . . _:b369426303 "2"^^ . _:b369426096 . _:b369426302 "2"^^ . _:b369426297 "2"^^ . _:b369426296 "2"^^ . _:b369426299 "2"^^ . _:b369426298 "2"^^ . _:b369426309 "2"^^ . _:b369426308 "2"^^ . _:b369426311 "2"^^ . _:b369426413 . _:b369426417 . _:b369426310 "2"^^ . . _:b3097153 . . _:b369426303 . _:b369426305 "2"^^ . _:b3097189 . _:b369426304 "2"^^ . _:b3097158 "Physiologic activation of the Akt pathway is regulated, in part, by a negative feedback loop involving phosphorylation of insulin receptor substrate 1 (IRS1) by the mTOR effector molecule S6 kinase 1 (Figure 4A) [>>23<<\u201326]. mTOR inhibition by rapamycin can cancel this negative feedback and activate Akt in some cancer cell lines and tumor samples, but the potential clinical impact is unknown [8,27,28]." . _:b369426307 "2"^^ . . _:b369426306 "2"^^ . _:b369426336 . _:b369426317 "2"^^ . . _:b369426110 . _:b369426316 "2"^^ . . . _:b369426319 "2"^^ . . _:b369426318 "2"^^ . _:b369426313 "2"^^ . . _:b369426312 "2"^^ . _:b369426113 . . . _:b3097138 . _:b369426315 "2"^^ . _:b3097148 . . _:b369426314 "2"^^ . . _:b369426325 "2"^^ . _:b3097165 . _:b3097149 "Patients whose tumors had PTEN loss were identified using a previously reported semi-quantitative scoring system that evaluates PTEN expression in tumor cells relative to adjacent vascular endothelial cells [>>17<<,18]. We screened tumor samples obtained at the time of initial surgery (S1) from 165 glioblastoma patients followed at our institution for subsequent neuro-oncology care." . _:b369426324 "2"^^ . _:b369426156 . . _:b369426327 "2"^^ . _:b369426085 . _:b369426326 "2"^^ . _:b3097173 . _:b369426014 . _:b369426321 "2"^^ . _:b369426446 . _:b369426320 "2"^^ . . . . _:b369426323 "2"^^ . _:b369426230 . _:b369426322 "2"^^ . _:b369426392 . _:b369426333 "2"^^ . _:b369426018 . . . _:b369426332 "2"^^ . _:b369426335 "2"^^ . _:b369426334 "2"^^ . _:b369426157 . . . _:b369426329 "2"^^ . _:b369426328 "2"^^ . . _:b369426331 "2"^^ . . _:b369426293 . _:b369426217 . _:b369426330 "2"^^ . . . _:b369426341 "2"^^ . _:b369426340 "2"^^ . . . . _:b369426343 "2"^^ . . _:b369426493 . _:b369426120 . . _:b369426342 "2"^^ . _:b369426337 "2"^^ . _:b369426426 . . _:b369426336 "2"^^ . _:b369426339 "2"^^ . _:b369425962 . _:b369426338 "2"^^ . _:b369426228 . . _:b369426349 "2"^^ . _:b369426348 "2"^^ . _:b369426369 . _:b369426351 "2"^^ . _:b369426073 . _:b369426350 "2"^^ . . _:b369426345 "2"^^ . _:b369426344 "2"^^ . _:b369426489 . _:b369426347 "2"^^ . _:b3097142 "Inhibitors of the mammalian target of rapamycin (mTOR) have received regulatory approval as immunosuppressive agents for the treatment of allograft rejection and as antitumor agents for kidney cancer [>>6<<,7]. Rapamycin and its analogs (CCI-779, RAD001) have shown antitumor activity across a variety of human cancers in clinical trials, but molecular determinants of drug response are currently unknown [8]." . _:b369426220 . _:b369426346 "2"^^ . _:b369426357 "2"^^ . _:b369426356 "2"^^ . _:b369426359 "2"^^ . _:b369426207 . _:b369426358 "2"^^ . _:b369426449 . _:b369426353 "2"^^ . _:b369426350 . _:b369426352 "2"^^ . _:b369426360 . _:b369426355 "2"^^ . _:b369426341 . _:b369426354 "2"^^ . _:b369426365 "2"^^ . _:b369426364 "2"^^ . _:b369426367 "2"^^ . _:b369426353 . _:b369426366 "2"^^ . _:b369426361 "2"^^ . _:b369426056 . _:b369426360 "2"^^ . . _:b369426121 . . _:b3097175 "As predicted from preclinical studies [27,>>28<<], rapamycin also led to the activation of Akt in some cases, and this activation was significantly correlated with shorter time-to-tumor progression." . _:b369426363 "2"^^ . _:b369426362 "2"^^ . . _:b369426373 "2"^^ . . . _:b369426372 "2"^^ . _:b369426484 . _:b3097182 . _:b369426111 . _:b369426375 "2"^^ . . _:b369426482 . _:b369426374 "2"^^ . _:b369426369 "2"^^ . . _:b369426368 "2"^^ . _:b369426371 "2"^^ . _:b369426370 "2"^^ . _:b369426381 "2"^^ . . _:b369426380 "2"^^ . . _:b369426383 "2"^^ . . _:b369426275 . _:b369426189 . _:b369426382 "2"^^ . _:b369426377 "2"^^ . . _:b369426376 "2"^^ . _:b369426305 . . . _:b369426379 "2"^^ . _:b369426378 "2"^^ . . _:b369426389 "2"^^ . . _:b369426388 "2"^^ . _:b369426391 "2"^^ . . _:b369426390 "2"^^ . _:b369426236 . _:b369426385 "2"^^ . . . . _:b369426384 "2"^^ . . _:b369426049 . . _:b369426387 "2"^^ . _:b369426466 . _:b369426386 "2"^^ . _:b369426397 "2"^^ . . _:b369425972 . _:b369426396 "2"^^ . . _:b369426399 "2"^^ . _:b369426140 . . _:b369426398 "2"^^ . _:b369426397 . _:b369426393 "2"^^ . _:b369426227 . _:b369426392 "2"^^ . _:b369426125 . _:b3097183 . _:b369426395 "2"^^ . _:b369426406 . _:b369426394 "2"^^ . . _:b369426405 "2"^^ . _:b369426404 "2"^^ . _:b369426407 "2"^^ . . _:b369426406 "2"^^ . . . _:b369426401 "2"^^ . . . _:b369426245 . _:b369426400 "2"^^ . _:b369426403 "2"^^ . _:b369426422 . _:b369426203 . . _:b369426402 "2"^^ . _:b369426413 "2"^^ . . _:b369426412 "2"^^ . . _:b369426024 . _:b369426415 "2"^^ . _:b369426109 . _:b369426414 "2"^^ . _:b369426409 "2"^^ . _:b369426408 "2"^^ . _:b369426411 "2"^^ . _:b369426062 . _:b369426410 "2"^^ . _:b369426421 "2"^^ . . . _:b369426420 "2"^^ . . _:b369426423 "2"^^ . _:b369426422 "2"^^ . . _:b369426417 "2"^^ . _:b369426416 "2"^^ . _:b369426436 . . _:b369426419 "2"^^ . _:b369426418 "2"^^ . _:b369426234 . _:b369426429 "2"^^ . _:b369426428 "2"^^ . _:b369426431 "2"^^ . . _:b369426430 "2"^^ . . _:b369426425 "2"^^ . _:b369426149 . _:b369426424 "2"^^ . _:b369426427 "2"^^ . . _:b369426426 "2"^^ . _:b369426468 . _:b369426167 . . _:b3097141 . . . . . . . _:b369425983 . . _:b369426458 . _:b369426166 . _:b369426487 . _:b369426381 . . _:b369426010 . _:b369426372 . _:b369426086 . _:b369426123 . _:b369426099 . _:b369426081 . _:b3097162 . . _:b369425977 . _:b369426368 . _:b369426469 . . . . . . . _:b369426060 . _:b369426402 . . . . . . _:b369426084 . _:b369426072 . _:b3097176 "While our trial was underway, a single-arm phase II study of the mTOR inhibitor CCI-779 reported that 20 of 65 patients with recurrent glioblastoma (36%) had radiographic improvement [>>39<<]. Of note, these patients were not evaluated prospectively for PTEN status (no molecular selection criteria), and CCI-779 was delivered weekly rather than daily based on a phase I experience that defined a maximum tolerated dose using" . . _:b369426012 . . _:b369426387 . _:b369426366 . _:b3097188 "Indeed, one dual PI3K/mTOR inhibitor has shown superiority to a pure mTOR inhibitor in preclinical models [>>49<<]." . _:b3097146 "Previous work by our group [9] and others [>>10<<\u201315] demonstrated that mutational activation of the phosphatidyl-inositol-3-kinase (PI3K) pathway through loss of PTEN (phosphatase and tensin homolog deleted on Chromosome 10) or activation of the serine/threonine kinase Akt sensitizes" . _:b369426264 . _:b369426101 . . . _:b369426196 . _:b369426151 . _:b369426334 . _:b3097138 "introduction" . . _:b369426040 . . _:b369426194 . _:b369426378 . . _:b369426198 . . _:b369426265 . _:b3097145 "Rapamycin and its analogs (CCI-779, RAD001) have shown antitumor activity across a variety of human cancers in clinical trials, but molecular determinants of drug response are currently unknown [8]. Previous work by our group [>>9<<] and others [10\u201315] demonstrated that mutational activation of the phosphatidyl-inositol-3-kinase (PI3K) pathway through loss of PTEN (phosphatase and tensin homolog deleted on Chromosome 10) or activation of the serine/threonine kinase" . _:b369425965 . _:b369426035 . . _:b369426428 . . . . . . . _:b369426037 . _:b369426210 . _:b369426463 . . _:b369426425 . _:b369426289 . . _:b369426180 . . _:b369426122 . . . . . . . _:b369426141 . . . _:b369426410 . _:b369426277 . _:b369426491 . _:b369426296 . _:b369426202 . _:b369426020 . _:b3097157 . . _:b369426326 . . _:b369426005 . . _:b369426143 . . _:b369426416 . . . _:b3097142 . . _:b369425984 . _:b369426269 . _:b369426050 . . . . _:b369426324 . _:b369426312 . . . . _:b369426036 . _:b369426261 . . . _:b369425968 . . _:b369426015 . _:b369426317 . . . _:b369426452 . _:b369426453 . _:b369426454 . _:b369426455 . _:b369426448 . _:b369426449 . _:b369426145 . _:b369426365 . _:b369426450 . _:b369426138 . _:b369426451 . _:b369426460 . _:b369426461 . _:b369426462 . _:b369426463 . _:b369426456 . _:b369426457 . _:b369426458 . _:b369426459 . _:b369426316 . _:b369426436 . . _:b369426437 . _:b369426438 . _:b369426439 . _:b369426226 . _:b369426432 . _:b3097164 . _:b3097158 . _:b369426433 . _:b369426434 . _:b369426435 . . _:b3097178 . _:b369426444 . _:b369426445 . _:b369426446 . _:b369426447 . . _:b369426440 . _:b369426441 . _:b369426442 . _:b369426443 . _:b369425957 . _:b369426484 . _:b369426485 . _:b369426486 . _:b369426487 . _:b369426480 . _:b369426481 . _:b369426421 . _:b369426482 . _:b369426465 . _:b369426483 . _:b369426492 . _:b369426493 . _:b369426494 . _:b369426495 . _:b369426488 . _:b369426489 . _:b3097191 "to other cancers in which experimental drug delivery can be timed prior to a planned surgical excision of tumor, and such an approach is consistent with recent national efforts to speed clinical development through novel trial designs [>>52<<]." . _:b369426501 . _:b369426490 . . _:b369426491 . _:b369426468 . _:b369426469 . _:b369426470 . _:b369426471 . . _:b369426464 . _:b369426465 . _:b369426466 . _:b369426467 . _:b369426476 . _:b369426398 . _:b369426477 . _:b369426478 . _:b369426479 . _:b369426472 . _:b369426473 . _:b369426474 . _:b369426475 . _:b369426229 . . . _:b369426500 . _:b369426501 . _:b369426502 . _:b369426503 . _:b369426496 . _:b369426497 . _:b369426498 . _:b369426499 . . _:b3097154 "This paradox might be explained by mTOR-independent phosphorylation of the 235/236 site [>>20<<,21] and suggests that the 240/244 site may be a preferred endpoint for assessment of mTOR activity." . _:b369426504 . _:b369426505 . _:b369426506 . . _:b369426337 . _:b3097184 "Based on earlier work from us and others, combined EGFR/mTOR blockade is one logical choice, because PTEN loss predicts for resistance to EGFR inhibitors in patients with the mutant EGFRviii variant [>>18<<,46\u201348]. Another possibility is combined PI3K/mTOR blockade to prevent rapamyin-induced activation of Akt caused by loss of negative feedback [27,28]. The time-to-progression analysis in our study suggests that the prognosis of these" . _:b369426196 . . _:b369426197 . _:b369426198 . _:b369426199 . _:b369426192 . _:b369426193 . _:b369426194 . _:b369426195 . _:b369426204 . _:b369426205 . _:b369426206 . _:b369426207 . _:b369426200 . _:b369426201 . _:b369426202 . . _:b369426370 . _:b369426203 . . . _:b369426292 . _:b369426180 . _:b369426181 . _:b369426182 . . . _:b369426183 . _:b369426176 . _:b369426177 . _:b369426178 . _:b369426179 . . _:b369426188 . _:b369426189 . _:b369426190 . _:b369426191 . _:b369426184 . _:b369426185 . _:b369426186 . _:b369426187 . . _:b369426228 . _:b369426229 . _:b369426230 . _:b369426231 . _:b369426224 . _:b369426225 . _:b369426226 . . _:b369426227 . _:b369426236 . _:b369426237 . _:b369426238 . _:b369426239 . _:b369426232 . _:b369426233 . _:b369426234 . _:b369426235 . _:b369426412 . _:b369426212 . _:b369426213 . _:b369426214 . . _:b369426215 . . _:b369426208 . _:b369426008 . _:b369426209 . _:b369426210 . . _:b369426211 . _:b369426220 . _:b369426430 . . . _:b369426221 . _:b369426222 . _:b369426223 . _:b369426328 . _:b369426216 . _:b369426217 . _:b369426218 . _:b369426219 . _:b369426260 . _:b369426261 . . _:b369426262 . _:b369426263 . _:b369426256 . _:b369426257 . _:b369426258 . _:b369426259 . _:b369426268 . _:b369426269 . _:b369426270 . _:b369426271 . . _:b369426264 . _:b369426265 . _:b369426266 . _:b369426267 . _:b369426244 . _:b369426245 . _:b369426246 . _:b369426247 . _:b369426240 . . _:b369426241 . . _:b369426242 . _:b369426243 . _:b369426252 . _:b369426253 . _:b369426254 . _:b369426255 . _:b369426248 . _:b369426249 . _:b369426250 . _:b369426251 . _:b369426292 . _:b369426293 . _:b369426294 . _:b369426295 . _:b369426288 . _:b369426289 . _:b369426290 . _:b369426291 . _:b369426300 . _:b369426168 . _:b369426301 . _:b369426302 . _:b369426303 . _:b369426296 . _:b369426297 . . _:b369426298 . _:b369426441 . _:b369426299 . _:b369426276 . _:b369426277 . _:b369426278 . _:b369426279 . _:b369426237 . _:b369426272 . _:b369426273 . _:b369426274 . _:b369426275 . _:b369426284 . _:b369426285 . _:b369426286 . _:b369426287 . _:b369426280 . _:b369426281 . _:b369426282 . _:b369426283 . _:b369426324 . _:b369426144 . _:b369426325 . _:b369426326 . _:b369426327 . _:b369426320 . _:b369426321 . _:b369426322 . _:b369426323 . _:b369426332 . _:b369426333 . _:b369426055 . _:b369426334 . _:b369426335 . _:b369426328 . _:b369426329 . _:b369426330 . _:b369426331 . _:b369426308 . _:b369426309 . . _:b369426310 . _:b369426311 . _:b369426304 . _:b369426305 . _:b369426306 . . _:b369426307 . _:b369426316 . _:b369426306 . . _:b369426317 . _:b369426318 . _:b369426319 . _:b369426312 . _:b369426270 . _:b369426313 . _:b3097156 "the two antibodies, changes in pSer235/236 were statistically more significantly linked to Ki-67 response, even though this site is believed to be less specific for S6K1 activity than pSer240/244 due to phosphorylation by other kinases [>>20<<]. This finding may reflect true biological differences in the input to these distinct phosphorylation sites or may be due to the relative sensitivity of the antibodies for detecting quantitative differences in mTOR inhibition." . _:b369426314 . _:b369426315 . _:b369426356 . _:b369426357 . _:b369426358 . _:b369426359 . _:b369426352 . _:b369426353 . _:b369426354 . _:b369426355 . _:b369426364 . . _:b369426365 . _:b369426366 . _:b3097155 "This paradox might be explained by mTOR-independent phosphorylation of the 235/236 site [20,>>21<<] and suggests that the 240/244 site may be a preferred endpoint for assessment of mTOR activity." . _:b369426367 . _:b369426360 . _:b369426361 . _:b369426362 . _:b369426363 . _:b369426340 . _:b369426341 . _:b369426342 . _:b369426343 . _:b3097185 . _:b369426336 . _:b369426337 . _:b369426338 . _:b369426339 . _:b369426348 . . _:b369426349 . _:b369426350 . _:b369426351 . _:b369426344 . _:b369426345 . _:b369426346 . _:b369426347 . _:b369426388 . _:b369426300 . _:b369426389 . _:b369426390 . _:b369426391 . _:b369426384 . _:b369426385 . _:b369426386 . _:b369426387 . _:b369426396 . _:b369426397 . _:b369426398 . _:b369426399 . _:b369426392 . . _:b369426393 . _:b369426394 . _:b369426395 . _:b369426372 . _:b369426373 . _:b369426374 . _:b369426375 . _:b369426368 . _:b369426369 . _:b369426370 . _:b369426371 . _:b369426380 . . _:b369426381 . _:b369426382 . _:b369426383 . _:b369426376 . _:b369426377 . _:b369426378 . _:b369426260 . _:b369426379 . _:b369426420 . _:b369426421 . _:b369426422 . _:b369426423 . _:b369426416 . _:b369426417 . _:b369426418 . . _:b369426419 . _:b369426428 . _:b369426429 . _:b369426430 . _:b369426431 . _:b369425969 . _:b369426424 . . _:b369426425 . _:b369426426 . . . _:b369426427 . _:b369426404 . _:b369426405 . _:b369426406 . _:b369426407 . _:b369426400 . _:b369426429 . _:b369426401 . _:b369426402 . _:b369426403 . _:b369426412 . _:b369426413 . _:b369426129 . _:b369426414 . _:b369426415 . _:b369426408 . _:b369426409 . _:b369426410 . _:b369426411 . _:b369426258 . . _:b369426373 . _:b369426108 . _:b369426329 . _:b369426065 . _:b369425972 . _:b369425973 . . _:b369425974 . _:b369425975 . _:b369425968 . _:b369425969 . _:b369426025 . _:b369425970 . _:b369425971 . . _:b369425980 . _:b369425981 . _:b369425982 . _:b369425983 . _:b369425976 . . _:b369425977 . _:b369426241 . _:b369425978 . _:b369426253 . _:b369425979 . _:b369425956 . _:b369425957 . . _:b369425958 . _:b369425959 . . _:b369425955 . _:b369425964 . _:b369425965 . _:b369425966 . _:b369425967 . _:b369425960 . _:b369425961 . . _:b369425962 . _:b369426225 . _:b369425963 . _:b369426004 . _:b369426005 . _:b369426006 . _:b369426007 . _:b369426000 . _:b369426001 . _:b369426409 . _:b369426002 . _:b369426003 . _:b369426012 . _:b369426323 . _:b369426013 . _:b369426014 . _:b369426423 . _:b369426015 . _:b369426008 . _:b369426009 . _:b369426010 . . _:b3097155 . _:b369426011 . _:b369426107 . _:b369425988 . _:b369425989 . . _:b369425990 . _:b369426042 . . _:b369425991 . _:b369425984 . _:b369425985 . _:b369425986 . _:b369425987 . _:b369425996 . _:b369425997 . _:b369425998 . _:b369425999 . _:b369425992 . _:b369425993 . _:b369425994 . _:b369425995 . _:b369426036 . _:b369426037 . _:b369426038 . _:b369426039 . _:b369426032 . _:b369426033 . _:b369426034 . _:b369426035 . _:b369426044 . _:b369426045 . _:b369426046 . _:b369426047 . _:b369426040 . _:b369426041 . _:b369426042 . _:b369426043 . _:b369426504 . _:b369426020 . _:b369426021 . _:b369426022 . _:b369426023 . _:b369426016 . _:b369426017 . _:b369426018 . _:b369426019 . _:b369426028 . _:b369426029 . _:b369426030 . _:b369426031 . _:b369426024 . _:b369426025 . _:b369426004 . _:b369426026 . . . _:b369426027 . _:b369426068 . _:b369426069 . _:b369426070 . _:b369426071 . _:b369426064 . _:b3097170 "of the PTEN gene (exon 1 and the 5\u2032 untranslated region [UTR] not sequenced) or the insensitivity of these methods when using heterogeneous tumor samples (the definition of PTEN deficiency used for the IHC test was >20% of tumor cells) [>>37<<]." . _:b369426065 . _:b369426066 . _:b369426067 . _:b369426076 . . _:b369426077 . _:b369426078 . _:b369426079 . _:b369426072 . _:b369426073 . . _:b369426074 . _:b369426075 . . _:b369426052 . _:b369426053 . _:b369426054 . _:b369426055 . _:b369426048 . _:b3097152 "Rapamycin concentrations known to confer antiproliferative activity in PTEN-null cell lines in vitro are typically \u223C1 nM [9,>>11<<]." . _:b369426049 . _:b369426050 . _:b369426051 . _:b369426060 . _:b369426061 . _:b369426062 . _:b369426063 . _:b369426056 . _:b369426057 . _:b369426058 . _:b369426059 . _:b369426100 . _:b369426101 . _:b369426273 . _:b369426102 . _:b369426103 . _:b369426096 . . _:b369426097 . _:b369426098 . _:b369426205 . _:b369426099 . _:b369426108 . _:b369426109 . _:b369426110 . . _:b369426111 . _:b369426104 . . _:b369426105 . _:b369426106 . _:b369426107 . _:b369426084 . . _:b369426085 . . _:b369426086 . _:b369426087 . _:b369426080 . _:b369426081 . _:b369426082 . _:b369426083 . _:b3097144 "Rapamycin and its analogs (CCI-779, RAD001) have shown antitumor activity across a variety of human cancers in clinical trials, but molecular determinants of drug response are currently unknown [>>8<<]. Previous work by our group [9] and others [10\u201315] demonstrated that mutational activation of the phosphatidyl-inositol-3-kinase (PI3K) pathway through loss of PTEN (phosphatase and tensin homolog deleted on Chromosome 10) or activation" . _:b369426092 . _:b369426093 . _:b369426094 . _:b369426095 . . _:b369426314 . _:b369426088 . _:b369426089 . _:b369426090 . _:b369426091 . _:b369426132 . _:b3097163 . _:b369426133 . _:b369426134 . _:b369426135 . . _:b369426128 . _:b369426333 . _:b369426129 . . _:b369426130 . _:b369426131 . . _:b369426140 . _:b369426141 . _:b369426142 . _:b369426143 . . _:b369426136 . _:b369426137 . _:b369426138 . _:b369426139 . _:b369426116 . _:b369426117 . _:b369426118 . _:b369426119 . _:b369426112 . _:b369426361 . _:b369426113 . _:b369426114 . _:b369426115 . _:b369426124 . _:b369426125 . _:b369426126 . _:b369426127 . _:b369426120 . _:b369426121 . _:b369426122 . _:b369426123 . _:b369426164 . _:b369426165 . _:b369426166 . . _:b369426167 . _:b369426160 . _:b369426161 . . _:b369426162 . _:b369426163 . _:b369426172 . _:b369426173 . _:b369426174 . _:b369426175 . _:b369426168 . _:b369426169 . _:b369426170 . . _:b369426171 . _:b369426148 . _:b369426149 . _:b369426494 . _:b369426150 . _:b369426151 . _:b369426144 . _:b369426145 . _:b369426146 . _:b369426147 . _:b369426156 . _:b369426157 . _:b369426158 . _:b369426159 . _:b369426152 . _:b369426153 . _:b369426154 . _:b369425978 . _:b369426155 . . _:b369426396 . _:b369426252 . . . _:b369426034 . _:b369426090 . _:b369426177 . . _:b369426325 . _:b369426216 . . . . _:b369426445 . _:b369426290 . . _:b369426174 . _:b369425975 . . _:b369425979 . _:b369426299 . . _:b369426443 . _:b369426181 . . _:b369426180 . _:b369426183 . _:b369426282 . _:b369426182 . _:b3097185 . _:b369426177 . . _:b369426176 . _:b369426332 . _:b369426066 . _:b369426179 . _:b369426178 . _:b369426189 . _:b369426188 . _:b369426461 . _:b369426069 . _:b369426191 . _:b369426351 . . _:b369426190 . _:b369426185 . _:b369426184 . _:b3097146 . . _:b369426187 . _:b369426186 . _:b369426254 . _:b369426197 . _:b369426321 . . _:b369426196 . _:b369426488 . _:b369426288 . . _:b369426199 . _:b369426162 . _:b369426483 . . _:b369426198 . _:b369426193 . . . . _:b369425998 . _:b369426192 . _:b369426195 . _:b369426194 . . _:b369426276 . _:b369426205 . _:b369426204 . _:b369426105 . _:b369426207 . . _:b369426206 . _:b3097143 . _:b369426201 . _:b369426200 . _:b369426322 . _:b369426203 . _:b369426202 . . _:b369426170 . _:b369426213 . _:b369425973 . _:b369426212 . _:b369426302 . _:b369426215 . _:b3097156 . _:b369426214 . . _:b369426209 . . _:b369426208 . . _:b369426076 . _:b369426211 . _:b369426201 . _:b369426210 . _:b369426221 . _:b3097154 . _:b369426080 . _:b369426263 . _:b369426220 . _:b369426223 . _:b3097180 . _:b369426223 . _:b369426222 . _:b369426438 . _:b369426217 . . _:b369426248 . . _:b369426216 . . _:b3097138 _:b3097144 . . _:b369426219 . _:b3097138 _:b3097145 . _:b3097138 _:b3097146 . _:b3097138 _:b3097147 . _:b3097138 _:b3097140 . _:b369426218 . _:b3097138 _:b3097141 . _:b3097138 _:b3097142 . _:b3097138 _:b3097143 . _:b369426229 . . _:b3097138 _:b3097139 . _:b369426228 . _:b3097166 . . _:b369426231 . . . . _:b369426230 . _:b3097148 _:b3097149 . _:b3097148 _:b3097150 . . _:b3097148 _:b3097151 . _:b369426225 . _:b369426224 . . . _:b369426227 . _:b369426226 . . _:b369426452 . _:b369426237 . _:b369426068 . _:b369426236 . _:b3097148 _:b3097168 . _:b369426239 . _:b3097148 _:b3097169 . _:b3097148 _:b3097170 . . . . _:b369426238 . . . . _:b369426233 . _:b369426327 . _:b3097148 _:b3097156 . _:b369426232 . _:b3097148 _:b3097157 . _:b3097148 _:b3097158 . _:b3097188 . _:b3097148 _:b3097159 . _:b3097148 _:b3097152 . _:b369426235 . _:b3097148 _:b3097153 . _:b3097148 _:b3097154 . _:b3097148 _:b3097155 . _:b3097148 _:b3097164 . . _:b369426234 . _:b369426295 . _:b3097148 _:b3097165 . _:b3097148 _:b3097166 . _:b3097150 "Patients whose tumors had PTEN loss were identified using a previously reported semi-quantitative scoring system that evaluates PTEN expression in tumor cells relative to adjacent vascular endothelial cells [17,>>18<<]. We screened tumor samples obtained at the time of initial surgery (S1) from 165 glioblastoma patients followed at our institution for subsequent neuro-oncology care." . _:b3097148 _:b3097167 . . _:b3097148 _:b3097160 . _:b369426245 . _:b3097148 _:b3097161 . _:b3097148 _:b3097162 . _:b3097148 _:b3097163 . . _:b369426244 . _:b369426250 . . _:b369426247 . _:b369426246 . _:b369426241 . _:b369426231 . _:b369426243 . _:b369426240 . _:b369426243 . _:b369426242 . . _:b369426253 . . _:b369426252 . _:b369426255 . _:b369426254 . _:b369426249 . _:b369426495 . _:b369426248 . _:b369426251 . _:b369426250 . . _:b369426261 . _:b369426260 . . _:b369426263 . . _:b369426262 . _:b369426257 . _:b3097189 "Recently, mTOR inhibitors have shown clinical activity in metastatic kidney cancer, where the frequency of PTEN loss is low [>>50<<]. The molecular basis for sensitivity in this disease is unknown, but loss of the von Hippel-Lindau (VHL) tumor suppressor and subsequent mTOR-dependent HIF-1\u03B1 expression is one postulated mechanism [51]. For reasons similar to those" . _:b369426088 . _:b369426256 . _:b369426259 . _:b369426164 . _:b369426258 . . _:b369426269 . _:b369425996 . _:b369426271 . _:b369426499 . . _:b369426268 . . _:b369426271 . _:b369426297 . _:b369426270 . _:b369426016 . . . _:b369426095 . _:b369426265 . . _:b369426264 . _:b369426115 . _:b369426267 . _:b369426266 . _:b369425955 . _:b369426277 . _:b369426276 . _:b369426279 . . _:b369426278 . _:b369426153 . . _:b369425997 . _:b369426273 . _:b369426272 . _:b369426275 . _:b369426097 . _:b369426274 . . _:b3097190 "The molecular basis for sensitivity in this disease is unknown, but loss of the von Hippel-Lindau (VHL) tumor suppressor and subsequent mTOR-dependent HIF-1\u03B1 expression is one postulated mechanism [>>51<<]. For reasons similar to those articulated above for glioblastoma, mTOR-based combination therapies are also under consideration in kidney cancer. The neoadjuvant clinical trial design described here should be easily exportable to other" . _:b3097139 . . _:b369426285 . _:b369426384 . . _:b369426284 . _:b3097140 . _:b369426287 . . _:b369426286 . _:b369426281 . _:b3097177 . _:b369426280 . _:b369426283 . _:b369426433 . _:b369426282 . . . . _:b369426293 . _:b369426142 . _:b369426292 . _:b369426104 . _:b369426295 . _:b369426311 . . _:b3097173 . _:b369426335 . _:b369426294 . _:b369426175 . _:b369426289 . _:b369426047 . _:b369426181 . _:b369426288 . _:b369426291 . _:b369426290 . . _:b369426301 . _:b369426300 . _:b369426303 . . _:b369426302 . _:b369426297 . _:b369426296 . _:b369425991 . . _:b369426299 . _:b369426298 . . . _:b369426309 . _:b369426345 . _:b369426308 . . _:b369426311 . _:b369426147 . _:b369426331 . _:b369426478 . _:b369426310 . _:b369426098 . _:b369426305 . _:b369426106 . _:b369426304 . _:b369426307 . _:b369426306 . _:b369426317 . _:b369426178 . _:b369426316 . . . _:b369426319 . . _:b369426318 . _:b3097143 "Inhibitors of the mammalian target of rapamycin (mTOR) have received regulatory approval as immunosuppressive agents for the treatment of allograft rejection and as antitumor agents for kidney cancer [6,>>7<<]. Rapamycin and its analogs (CCI-779, RAD001) have shown antitumor activity across a variety of human cancers in clinical trials, but molecular determinants of drug response are currently unknown [8]." . _:b369426313 . _:b369425981 . _:b369426312 . . _:b369426315 . _:b369426314 . _:b369426325 . . _:b369426009 . . _:b369426324 . _:b369426327 . . _:b369426326 . _:b369426321 . . _:b369426320 . _:b369426323 . _:b369426195 . _:b369426322 . _:b369426333 . _:b369426028 . . . _:b369426332 . _:b369426335 . . _:b3097171 _:b3097184 . . _:b3097171 _:b3097185 . _:b369426334 . _:b3097171 _:b3097186 . _:b3097171 _:b3097187 . _:b3097171 _:b3097188 . _:b369426329 . _:b3097171 _:b3097189 . _:b3097171 _:b3097190 . _:b369426447 . _:b3097171 _:b3097191 . _:b369426367 . _:b369426328 . _:b369426490 . _:b369426502 . _:b369426331 . . _:b369426330 . _:b369426137 . _:b369426341 . _:b369426126 . _:b369426340 . _:b369426352 . _:b369426415 . _:b369426432 . . . _:b369426320 . _:b369426343 . _:b369426342 . _:b369426337 . _:b3097162 . _:b3097171 _:b3097176 . _:b369426336 . _:b3097171 _:b3097177 . _:b3097171 _:b3097178 . _:b3097171 _:b3097179 . _:b3097171 _:b3097180 . _:b369426339 . _:b3097171 _:b3097181 . _:b3097171 _:b3097182 . _:b3097171 _:b3097183 . _:b369426338 . _:b3097171 _:b3097172 . _:b369426349 . _:b3097171 _:b3097173 . _:b3097171 _:b3097174 . _:b3097171 _:b3097175 . "PMC0" . _:b369426348 . . _:b369426351 . _:b369426350 . . _:b369426393 . _:b369426345 . _:b3097140 "Such neoadjuvant studies have been successfully implemented with hormonal agents alone or in combination with kinase inhibitors in breast cancer [>>4<<,5]. Current technologies permit analyses of gene copy number, mutation status, and mRNA and protein expression from small tissue samples, thereby allowing for the collection of high\u2013molecular content datasets that can guide further" . _:b369426215 . _:b3097172 . . . _:b369426344 . _:b3097185 "Based on earlier work from us and others, combined EGFR/mTOR blockade is one logical choice, because PTEN loss predicts for resistance to EGFR inhibitors in patients with the mutant EGFRviii variant [18,>>46<<\u201348]. Another possibility is combined PI3K/mTOR blockade to prevent rapamyin-induced activation of Akt caused by loss of negative feedback [27,28]. The time-to-progression analysis in our study suggests that the prognosis of these patients" . _:b369426022 . _:b369426347 . _:b369426346 . _:b369426159 . _:b369426357 . _:b369426356 . _:b369426359 . _:b369426301 . _:b369426209 . _:b369426358 . _:b369426309 . _:b369426353 . _:b369426007 . _:b369426352 . _:b3097179 . . _:b369426355 . . . _:b369426354 . _:b369426200 . _:b369426179 . _:b369426500 . _:b369426365 . _:b369426364 . _:b3097141 "Such neoadjuvant studies have been successfully implemented with hormonal agents alone or in combination with kinase inhibitors in breast cancer [4,>>5<<]. Current technologies permit analyses of gene copy number, mutation status, and mRNA and protein expression from small tissue samples, thereby allowing for the collection of high\u2013molecular content datasets that can guide further clinical" . . . _:b369426367 . . _:b369426366 . _:b369426361 . . _:b369426360 . . _:b369426363 . _:b369426362 . _:b369425980 . _:b369426373 . _:b369426362 . _:b369426475 . _:b369426372 . _:b369426285 . . _:b369426375 . _:b369426197 . _:b369426374 . _:b369426369 . _:b369426368 . . _:b369426371 . . _:b369426370 . . _:b369425976 . _:b369426381 . . _:b369426380 . _:b369426383 . _:b369426382 . _:b369426377 . . _:b369426376 . _:b369426379 . _:b369426222 . _:b369426173 . _:b369426378 . . _:b3097167 . _:b369426389 . . _:b369426388 . _:b369425960 . . _:b369426342 . . _:b369426391 . _:b369426185 . _:b369426390 . _:b369426385 . . _:b3097177 "patients were not evaluated prospectively for PTEN status (no molecular selection criteria), and CCI-779 was delivered weekly rather than daily based on a phase I experience that defined a maximum tolerated dose using this schedule [>>40<<,41]. In light of our findings about the magnitude of mTOR inhibition required for response (discussed below), this schedule raises concerns about the presumed lack of target coverage during nontreatment days." . _:b369426384 . _:b369426387 . _:b369426089 . _:b369426386 . _:b369426497 . . _:b369426397 . . . _:b369426396 . . _:b369426399 . _:b369426398 . . . _:b369426393 . _:b369426392 . _:b369426238 . _:b3097151 "Rapamycin concentrations known to confer antiproliferative activity in PTEN-null cell lines in vitro are typically \u223C1 nM [>>9<<,11]." . _:b369426395 . _:b369426375 . _:b369426448 . _:b369426163 . _:b369425999 . . _:b369426444 . _:b369426394 . . _:b369426405 . _:b369426404 . _:b369426407 . . . _:b369426406 . _:b369426127 . _:b369426401 . _:b369426400 . . _:b369426403 . _:b369426152 . _:b369426402 . _:b3097181 . _:b369426413 . _:b369426274 . _:b369426412 . . _:b369426415 . . _:b369426414 . _:b369426146 . . _:b369426409 . _:b3097185 . . _:b369426408 . _:b369426411 . . _:b369426410 . _:b3097140 . _:b3097182 "For example, if rapamycin in these patients is sequestered in red cells due to enhanced tumor vascularity, antiangiogenic agents such as bevacizumab (already known to have activity in glioblastoma) [>>44<<] may prevent sequestration and allow more efficient drug delivery." . _:b369426421 . _:b3097141 . . _:b369426420 . _:b369426030 . _:b3097142 . . _:b369426423 . _:b3097143 . _:b369426388 . _:b369426422 . _:b369426417 . . _:b369426416 . _:b3097138 . _:b369426308 . _:b369426419 . _:b3097139 . _:b369426418 . _:b3097148 . _:b369426429 . _:b3097149 . . _:b3097171 "discussion" . . _:b3097150 . _:b369426428 . _:b369426356 . _:b369426431 . _:b3097151 . _:b369426430 . _:b3097144 . . . _:b3097145 . _:b369426425 . _:b369426279 . _:b369426424 . _:b3097146 . . . _:b369426427 . _:b369426204 . _:b3097147 . _:b369426426 . _:b3097156 . _:b3097157 . _:b369426124 . _:b369426148 . . _:b3097158 . _:b3097159 . _:b3097163 "had a significant decrease in PRAS40 phosphorylation (and pS473 Akt) at S2 (Figure 4B), which could reflect the potential inhibition of the TORC2 mTOR complex (implicated as the pS473 Akt kinase) by rapamycin after prolonged exposure [>>32<<,33]." . _:b3097152 . . . _:b369426280 . _:b369426032 . _:b3097153 . . _:b3097154 . _:b3097155 . . . _:b369426268 . _:b3097164 . . . _:b3097165 . _:b369426437 . _:b3097158 . _:b3097166 . _:b369426436 . _:b3097167 . _:b369426439 . _:b3097160 . _:b369426403 . _:b369426438 . _:b3097161 . . _:b369426433 . . _:b3097162 . _:b369426262 . _:b369426432 . _:b369426244 . _:b3097163 . _:b369426435 . _:b3097166 "these observations lacked statistical power due to the small sample size, it is interesting to note that EGFR has been reported to induce expression of IRS1, the mediator of the negative mTOR/S6K1 feedback loop, in breast cancer cells [>>35<<]. Furthermore, PDGFR is an additional target of mTOR negative feedback which can be overcome by enhanced PDGFR\u03B2 expression [36]." . _:b3097172 . . . _:b369426434 . _:b3097173 . _:b369426445 . _:b3097174 . _:b369426444 . _:b3097175 . . . _:b369426447 . _:b3097168 . _:b369425995 . _:b369426446 . _:b3097169 . . _:b369426441 . _:b369426172 . _:b3097170 . . _:b369426232 . _:b369426218 . _:b369426440 . _:b3097171 . _:b369426155 . _:b369426472 . _:b369426443 . _:b3097180 . . _:b369426442 . _:b3097181 . . _:b3097164 "a significant decrease in PRAS40 phosphorylation (and pS473 Akt) at S2 (Figure 4B), which could reflect the potential inhibition of the TORC2 mTOR complex (implicated as the pS473 Akt kinase) by rapamycin after prolonged exposure [32,>>33<<]." . _:b369426453 . _:b3097182 . _:b369426452 . _:b369426103 . _:b3097183 . _:b369426455 . _:b369425959 . _:b3097176 . _:b369426454 . . _:b3097177 . _:b369426449 . _:b3097178 . _:b369426448 . _:b3097179 . _:b369426451 . _:b3097188 . . _:b369426481 . _:b369426450 . _:b369425957 . _:b3097189 . . _:b369426461 . _:b369425956 . _:b3097190 . . _:b369426460 . _:b369425959 . _:b3097191 . . _:b369426463 . _:b369425958 . _:b3097184 . _:b369426355 . _:b369426462 . _:b3097185 . _:b369426457 . _:b3097186 . . _:b369426456 . _:b369425955 . _:b3097187 . _:b369425971 . _:b369426459 . _:b369426458 . _:b369425965 . _:b369426003 . _:b369426469 . _:b369425964 . . _:b3097139 "therapy, this approach has been questioned, because it is anticipated that these agents will be effective primarily in those patients whose tumors are dependent on the molecular lesion that is specifically targeted by the new agent [>>1<<\u20133]. However, target-focused clinical development is challenging, because clearly defined, validated molecular criteria to select patients for clinical trials must be established." . _:b369426468 . . . _:b369425967 . _:b369425967 . _:b369426471 . _:b369425966 . . _:b369426470 . _:b369425961 . _:b369426465 . _:b369425960 . _:b369426464 . _:b369425963 . . _:b369426467 . _:b369425962 . _:b369426466 . _:b369425973 . . _:b369426477 . _:b369425972 . _:b369426476 . _:b369425975 . . _:b369426479 . _:b369425974 . _:b369426478 . _:b369425969 . _:b369426408 . . _:b369426473 . _:b369425968 . . _:b369426472 . _:b369425971 . _:b369426475 . _:b369425970 . _:b369426474 . _:b369425981 . _:b369426485 . _:b369425980 . . _:b369426026 . _:b369426484 . _:b369425983 . _:b369426487 . _:b369425982 . _:b369426023 . _:b369426486 . _:b369425977 . _:b369426481 . _:b369425976 . _:b369426480 . _:b369425979 . . _:b369426371 . _:b369426139 . _:b369426483 . _:b369425978 . _:b369426482 . _:b369425989 . _:b369425987 . _:b3097147 "Indeed, others have used this salvage surgery to define the dose of O6-benzylguanine required to deplete the DNA-repair protein AGT, which is associated with resistance to temozolamide [>>16<<]. Importantly, the antitumor effects of mTOR inhibition in many preclinical models are cytostatic, raising the possibility that traditional radiographic clinical endpoints of tumor shrinkage may not be observed. Glioblastoma may be" . _:b369426493 . _:b369425988 . _:b369426492 . _:b369425991 . _:b369426495 . _:b369425990 . _:b369426079 . _:b369426494 . _:b369425985 . _:b369426489 . _:b369425984 . _:b3097153 "Both sites are directly phosphorylated by S6 kinase 1, but Ser235/236 can also be phosphorylated by p90 ribosomal S6 kinase (RSK) and other kinases [>>19<<]. All measurements were quantified by digital readout of 2,500\u20135,000 tumor cells per slide cut from paraffin-embedded tissue (Figure S1). We attempted to assess mTOR activity using phosphosite-specific antibodies against Thr389 of S6" . _:b369426488 . _:b369425987 . _:b369426491 . _:b369425986 . _:b369426490 . _:b369425997 . _:b369426501 . _:b369425996 . . _:b369426500 . _:b369425999 . _:b369426503 . _:b369425998 . _:b369426502 . . _:b369425993 . _:b369426497 . _:b369425992 . . _:b369425956 . _:b369426496 . . _:b369425995 . _:b369426499 . _:b369425994 . . _:b369426498 . _:b369425963 . _:b369426005 . _:b369426004 . _:b369426007 . . _:b369426006 . _:b369426070 . _:b369426044 . _:b369426001 . _:b369426114 . _:b369426505 . "10.1371%2Fjournal.pmed.0050008" . _:b369426000 . _:b369426504 . _:b369426003 . _:b369426046 . . . _:b369426002 . . . _:b369426506 . _:b369426013 . _:b369426012 . _:b369426015 . _:b369426354 . . _:b369426014 . _:b369426359 . _:b369426009 . _:b369426008 .