_:b511900826 . _:b511900820 . _:b20071496 "IGF-1R is implicated in proliferation and survival of many tumor types [>>14<<] and is overexpressed in PCa [15]." . . . _:b20071529 "However, as shown in the Src-/- mouse [>>39<<], Src is also an important regulator of osteoclast function, and this is confirmed by bone preservation in dasatinib-alone treated cells (Fig." . _:b20071497 . . _:b20071484 "There are only 3 FDA-approved chemotherapeutic agents for CRPC: docetaxel and cabazitaxel [2], [>>3<<], both of which show only a modest survival advantage for men with CRPC, and more recently, the CYP17 inhibitor abiraterone acetate, approved for use after docetaxel failure (ClinicalTrials." . _:b511900818 . _:b20071493 . . _:b511900816 . . _:b20071494 "Based in part on these findings and some promising results from a phase 1/2 trial [12], dasatinib, a small molecule multi-kinase inhibitor with selectivity forSFK/Abl [>>8<<], has been tested in combination with docetaxel in a randomized phase 3 trial for patients with CRPC (ClinicalTrials." . _:b20071489 "Preclinical data in PCa show that inhibition of SFKs decreases proliferation and, more strongly, invasion and migration [>>8<<], [9]. In addition, Src activity is important in the microenvironment, affecting osteoclast function. Thus, Src inhibitors block, in part, tumor/microenvironment interactions that lead to the \u201Cvicious cycle\u201D of bone metastasis [10]. In" . . _:b20071506 "in part by the Src pathway, other downstream signaling pathways of IGF-1R are Src independent and unaffected by Src inhibition [14]; these additional pathways have been shown recently to play an important role in PCa cell survival [>>23<<]. Activating Src and IGF-1R also activates Akt, a key effector of the PI3K/Akt/mTOR pathway, which is aberrantly activated in the majority of malignancies, promoting cell growth, proliferation, and survival [24], [25]." . _:b20071511 _:b20071520 . _:b20071511 _:b20071521 . _:b20071519 . _:b20071511 _:b20071522 . _:b20071511 _:b20071523 . _:b511900807 . . _:b20071518 . _:b20071512 . _:b20071511 _:b20071512 . _:b20071497 "IGF-1R is implicated in proliferation and survival of many tumor types [14] and is overexpressed in PCa [>>15<<]. IGF-1R signaling has been linked to PCa risk, and one of its ligands, IGF-2, is also overexpressed in PCa bone metastases [16], where it promotes proliferation and survival of PCa cells [17], [18], [19], [20], [21]. Studies with" . _:b20071511 _:b20071513 . _:b20071511 _:b20071514 . _:b20071511 _:b20071515 . _:b20071511 _:b20071516 . _:b20071502 "IGF-1R signaling has been linked to PCa risk, and one of its ligands, IGF-2, is also overexpressed in PCa bone metastases [16], where it promotes proliferation and survival of PCa cells [17], [18], [19], [>>20<<], [21]. Studies with monoclonal antibodies to IGF-1R have implicated this receptor as important in PCa progression in androgen-sensitive as well as -resistant tumor models [22]. Although IGF-1R signaling is mediated in part by the Src" . _:b20071511 _:b20071517 . _:b20071511 _:b20071518 . _:b20071511 _:b20071519 . _:b20071536 . . . _:b20071515 "Subcutaneous grafts of MDA PCa 133 (a xenograft from a castrate-resistant patient derived from a bone metastasis that expresses AR and PSA and grows only in mice and not in cell culture) were generated as described previously [>>30<<]. In brief, fragments of tumors were implanted subcutaneously into severe combined immunodeficient (SCID) mice at a size less than 1 mm3." . . _:b20071513 . _:b20071484 . _:b20071511 . . _:b20071482 . _:b20071499 "IGF-1R signaling has been linked to PCa risk, and one of its ligands, IGF-2, is also overexpressed in PCa bone metastases [16], where it promotes proliferation and survival of PCa cells [>>17<<], [18], [19], [20], [21]." . _:b20071485 . _:b20071486 . . . _:b20071487 . . _:b511900813 . _:b20071545 "Our findings are supported by two recent reports that identified activated Akt as a downstream effector of IGF-1\u2013mediated suppression of apoptosis in PC-3 cells [>>23<<] and also showed that in vitro and in vivo inhibition of migration/invasion by the Src inhibitor bosutinib is accompanied by inhibition of Akt phosphorylation [50]." . . _:b20071481 . _:b20071482 . _:b20071525 "SFK inhibition with dasatinib decreased proliferation of PC-3 cells, consistent with previous findings [>>11<<]; knockdown of IGF-1R decreased proliferation at 96 hours more than dasatinib did (P<0.05; S1C), and the combination of SFK inhibition and IGF-1R knockdown further decreased proliferation (P<0.05)." . _:b20071483 . _:b20071543 . . _:b20071492 . _:b20071542 . . _:b20071507 . _:b20071493 . _:b20071494 . _:b20071485 "gov Identifier: NCT00638690), improving overall survival by 3.9 months [>>4<<]. For minimally symptomatic metastatic CRPC, a randomized phase 3 trial showed survival advantage with the vaccine Sipuleucel-T [5]." . _:b20071495 . _:b511900819 . _:b20071521 "The cells were then harvested, and 500 \u00B5g of protein was used for immunoprecipitation, as described previously [>>35<<]. The samples were incubated with specific antibodies against Akt1 or Akt2 (Cell Signaling) overnight at 4\u00B0C. Following immunoprecipitation, 50 \u00B5L of protein A agarose beads were added, and the samples were incubated again for 2 hours at" . _:b20071524 . _:b20071488 . . _:b20071539 . _:b20071489 . _:b20071501 . . _:b20071490 . _:b20071537 "We have focused on the IGF-1/IGF-1R pathway because the activation of this pathway is important in PCa, the abundant expression of IGF-1 [42] in osteoblasts leads to frequent activation of IGF-1R in tumor cells [43], [>>44<<] and because IGF-1R may signal through compensatory pathways that blunt the effectiveness of Src inhibitors such as dasatinib." . _:b20071523 . _:b20071491 . . _:b20071530 . _:b20071500 . . _:b20071501 . _:b20071548 "Accrual of patients for that study is finished and overall survival results are pending [>>6<<]. Therefore, our study is of potential clinical importance as both inhibitors used in this work (although not in combination) are currently in clinical trials, and this work provides strong rationale for combining these two agents in men" . _:b20071502 . _:b20071503 . . _:b20071496 . _:b511900811 . _:b20071497 . _:b511900821 . _:b20071492 "In studies using in vivo orthotopic mouse experiments, inhibition of SFKs decreased both prostate tumor growth and development of lymph node metastases [>>11<<]. Based in part on these findings and some promising results from a phase 1/2 trial [12], dasatinib, a small molecule multi-kinase inhibitor with selectivity forSFK/Abl [8], has been tested in combination with docetaxel in a randomized" . _:b511900814 . _:b20071498 . _:b20071503 . _:b20071525 . _:b20071499 . . _:b20071534 "Examples of tumor/microenvironment interactions are the importance of Src family members activated in PCa [40], [41] in tumor growth and progression, as well as the importance of Src in osteoclast function [>>39<<]; thus, Src targeting affects both the tumor and microenvironment." . _:b20071487 "Thus, while promising agents are improving survival of PCa patients, additional therapeutic agents are clearly needed for advanced stage disease [>>6<<]." . _:b20071504 "Studies with monoclonal antibodies to IGF-1R have implicated this receptor as important in PCa progression in androgen-sensitive as well as -resistant tumor models [>>22<<]. Although IGF-1R signaling is mediated in part by the Src pathway, other downstream signaling pathways of IGF-1R are Src independent and unaffected by Src inhibition [14]; these additional pathways have been shown recently to play an" . . _:b20071508 . . _:b20071529 . _:b511900824 . _:b20071509 . . _:b511900815 . _:b20071510 . . _:b20071481 . _:b20071511 . . _:b20071535 . _:b20071504 . _:b20071489 . . _:b20071505 . _:b20071548 . _:b20071534 . _:b20071506 . _:b511900803 . _:b20071507 . . _:b20071516 . . _:b511900823 . _:b20071517 . _:b20071524 "results" . _:b20071494 . . _:b20071518 . . . _:b20071481 _:b20071482 . _:b20071519 . _:b20071481 _:b20071483 . _:b20071527 "4C, D), indicating modulation of both the PCa cells and their bone microenvironment, thus interfering with the vicious cycle [>>10<<]. Whereas the modification of murine N-telopeptide, a surrogate for osteoclast activity, is indicative of inhibition of the osteolytic PC3-MM2 cell line, the observed decrease in murine alkaline phosphatase (representing osteoblast" . _:b20071481 _:b20071484 . _:b20071513 "PC3-MM2 [>>28<<] and PC3-LG cells [29] were kindly provided by Dr. Isaiah Fidler (The University of Texas MD Anderson Cancer Center)." . . _:b20071481 _:b20071485 . _:b20071481 _:b20071486 . _:b20071512 . . _:b20071544 "These findings are in keeping with recent data showing in breast cancer that Erk1/2 phophorylation is not mediated by IGF-1, but rather insulin and IGF-2 [>>49<<]. Our findings are supported by two recent reports that identified activated Akt as a downstream effector of IGF-1\u2013mediated suppression of apoptosis in PC-3 cells [23] and also showed that in vitro and in vivo inhibition of" . _:b20071481 _:b20071487 . _:b20071481 _:b20071488 . _:b20071481 _:b20071489 . . _:b20071513 . _:b20071508 . _:b20071481 _:b20071490 . _:b20071481 _:b20071491 . _:b20071481 _:b20071492 . _:b20071481 _:b20071493 . _:b20071481 _:b20071494 . _:b20071514 . . _:b20071481 _:b20071495 . _:b20071481 _:b20071496 . _:b20071481 _:b20071497 . _:b20071547 "2C), which likely is explained by other kinases increased during prostate cancer progression, such as c-Met [>>52<<] and Axl [53]." . . _:b20071515 . _:b20071481 _:b20071498 . _:b20071481 _:b20071499 . _:b511900809 . _:b20071481 _:b20071500 . _:b20071481 _:b20071501 . _:b20071481 _:b20071502 . _:b20071524 . _:b20071508 "Activating Src and IGF-1R also activates Akt, a key effector of the PI3K/Akt/mTOR pathway, which is aberrantly activated in the majority of malignancies, promoting cell growth, proliferation, and survival [24], [>>25<<].However, whether these inhibitors are equally effective in inhibiting Akt1, 2, and 3 functions is not known, and if combining them produced better results in inhibiting this survival pathway was a goal of this work. Here, we examined the" . _:b20071481 _:b20071503 . _:b511900801 . _:b20071481 _:b20071504 . . _:b20071481 _:b20071505 . _:b20071481 _:b20071506 . _:b20071541 . _:b20071525 . _:b20071481 _:b20071507 . _:b20071481 _:b20071508 . _:b20071481 _:b20071509 . _:b20071481 _:b20071510 . _:b20071526 . _:b511900797 "4"^^ . _:b511900802 . _:b511900796 "4"^^ . _:b20071527 . _:b511900799 "3"^^ . . _:b20071526 . _:b20071520 . _:b20071514 . _:b511900798 "3"^^ . . _:b20071521 . . _:b20071515 . . _:b20071522 . _:b20071483 . _:b20071521 . _:b20071523 . _:b20071532 . _:b20071511 "materials and methods" . _:b20071533 . _:b20071495 . _:b20071506 . _:b511900805 "2"^^ . _:b20071534 . _:b511900804 "2"^^ . _:b20071500 "IGF-1R signaling has been linked to PCa risk, and one of its ligands, IGF-2, is also overexpressed in PCa bone metastases [16], where it promotes proliferation and survival of PCa cells [17], [>>18<<], [19], [20], [21]." . _:b20071535 . . . _:b511900807 "2"^^ . _:b20071526 "observed with BMS-754807 was more pronounced in both cell lines than with shIGF-1R, suggesting that the phenotype seen with BMS-754807 is likely due, in part, to the ability of BMS-754807 to inhibit the insulin receptor (IR) as well [>>26<<].To specifically examine the effects of BMS-754807 on IGF-1 stimulation of IGF-1R, we determined the effect of increasing doses of the inhibitor on PARP cleavage." . _:b20071537 . _:b20071528 . _:b511900806 "2"^^ . _:b20071500 . . _:b20071529 . _:b511900801 "2"^^ . "PMC0" . _:b20071530 . _:b20071535 "This strategy has led to a subset of patients who experience durable responses in a phase 1/2 dasatinib plus docetaxel trial [>>12<<], leading to a large randomized phase 3 trial with docetaxel in men with advanced metastatic PCa (NCT00744497)." . _:b511900800 . _:b511900800 "2"^^ . _:b20071531 . _:b511900803 "2"^^ . _:b20071492 . . _:b20071540 . _:b511900802 "2"^^ . _:b511900812 . _:b20071541 . . _:b511900813 "2"^^ . _:b20071542 . _:b511900812 "2"^^ . _:b20071504 . _:b20071543 . . . _:b20071523 "H&E and TUNEL staining were performed on MDA PCa 133 xenograft tumors after explantation as described previously [36], [>>37<<]. In each group, 5 different high-power fields (HPF) were examined, the number of TUNEL-positive cells was counted, and the average number of TUNEL-positive cells/HPF was calculated." . _:b20071498 . _:b511900815 "2"^^ . _:b20071519 "Intratibial injection of PC3-MM2 cells was performed as previously described [28]; briefly, nude mice were anesthetized as above, and 2.5\u00D7105 cells were injected into the tibia as described [>>28<<]. Twelve days after injection, the mice were treated with saline (n\u200A=\u200A10) dasatinib (n\u200A=\u200A9), BMS-754807 (n\u200A=\u200A9), or both(n\u200A=\u200A8) at the dosages described above." . _:b20071536 . _:b511900814 "2"^^ . _:b20071537 . _:b20071547 . _:b511900809 "2"^^ . _:b20071518 "Intratibial injection of PC3-MM2 cells was performed as previously described [>>28<<]; briefly, nude mice were anesthetized as above, and 2.5\u00D7105 cells were injected into the tibia as described [28]." . _:b20071538 . _:b511900808 "2"^^ . . _:b20071539 . _:b511900811 "2"^^ . . _:b20071488 "One of the most promising targets in PCa are the Src family kinases (SFKs), a family of non-receptor protein tyrosine kinases, the expression and specific activities of which are increased in multiple types of human tumors [>>7<<]. Preclinical data in PCa show that inhibition of SFKs decreases proliferation and, more strongly, invasion and migration [8], [9]. In addition, Src activity is important in the microenvironment, affecting osteoclast function. Thus, Src" . _:b20071548 . _:b511900810 "2"^^ . . _:b511900821 "2"^^ . _:b20071540 . _:b511900810 . _:b511900827 . _:b20071520 "Immunoblotting was performed as described previously [>>34<<]. Briefly, cells were lysed and clarified, and the proteins were separated via 8% SDS-PAGE, followed by transfer onto polyvinylidenedifluoride membranes (Millipore)." . _:b511900820 "2"^^ . _:b20071485 . _:b511900823 "2"^^ . _:b20071498 "IGF-1R signaling has been linked to PCa risk, and one of its ligands, IGF-2, is also overexpressed in PCa bone metastases [>>16<<], where it promotes proliferation and survival of PCa cells [17], [18], [19], [20], [21]." . _:b20071544 . _:b511900804 . _:b511900822 "2"^^ . _:b20071545 . _:b20071533 "Examples of tumor/microenvironment interactions are the importance of Src family members activated in PCa [40], [>>41<<] in tumor growth and progression, as well as the importance of Src in osteoclast function [39]; thus, Src targeting affects both the tumor and microenvironment." . _:b511900817 "2"^^ . . _:b20071546 . _:b20071543 "More importantly, the study by Vandyke et al. [>>48<<] examined the in vivo effects by treating mice with dasatinib for as many as 12 weeks." . _:b20071491 . _:b511900816 "2"^^ . _:b511900798 . _:b20071547 . _:b511900819 "2"^^ . _:b20071532 . _:b20071505 "Although IGF-1R signaling is mediated in part by the Src pathway, other downstream signaling pathways of IGF-1R are Src independent and unaffected by Src inhibition [>>14<<]; these additional pathways have been shown recently to play an important role in PCa cell survival [23]." . _:b511900818 "2"^^ . _:b20071510 "of dasatinib, an SFK inhibitor, and BMS-754807, a potent and reversible small molecule inhibitor of IGF-1R [26] and the insulin receptor (IR) with activity against various solid tumors in vitro as well as in multiple xenograft models [>>26<<]. As inhibitors have off-target effects, molecular knockdown of these pathways was also employed." . _:b20071490 . _:b511900828 "2"^^ . _:b20071503 "IGF-1R signaling has been linked to PCa risk, and one of its ligands, IGF-2, is also overexpressed in PCa bone metastases [16], where it promotes proliferation and survival of PCa cells [17], [18], [19], [20], [>>21<<]. Studies with monoclonal antibodies to IGF-1R have implicated this receptor as important in PCa progression in androgen-sensitive as well as -resistant tumor models [22]. Although IGF-1R signaling is mediated in part by the Src pathway," . _:b20071493 "Based in part on these findings and some promising results from a phase 1/2 trial [>>12<<], dasatinib, a small molecule multi-kinase inhibitor with selectivity forSFK/Abl [8], has been tested in combination with docetaxel in a randomized phase 3 trial for patients with CRPC (ClinicalTrials." . _:b20071505 . . . _:b20071490 "Preclinical data in PCa show that inhibition of SFKs decreases proliferation and, more strongly, invasion and migration [8], [>>9<<]. In addition, Src activity is important in the microenvironment, affecting osteoclast function. Thus, Src inhibitors block, in part, tumor/microenvironment interactions that lead to the \u201Cvicious cycle\u201D of bone metastasis [10]. In studies" . _:b511900822 . _:b511900825 "2"^^ . _:b20071536 "We have focused on the IGF-1/IGF-1R pathway because the activation of this pathway is important in PCa, the abundant expression of IGF-1 [42] in osteoblasts leads to frequent activation of IGF-1R in tumor cells [>>43<<], [44] and because IGF-1R may signal through compensatory pathways that blunt the effectiveness of Src inhibitors such as dasatinib." . _:b511900824 "2"^^ . _:b20071517 . _:b511900826 . _:b20071520 . . _:b20071516 . _:b511900827 "2"^^ . . _:b20071484 . _:b511900826 "2"^^ . . _:b20071546 "Wu et al recently showed Src inhibition affects Akt phosphorylation and induces autophagy in PC3 cells [>>51<<]. However, we have observed residual Akt phosphorylation independent of Src and IGF-1R pathways (Fig. 2C), which likely is explained by other kinases increased during prostate cancer progression, such as c-Met [52] and Axl [53]." . _:b20071531 "Emerging evidence suggests that successful treatment for advanced PCa will require targeting both the tumor and the microenvironment [>>10<<]. However, multiple bidirectional signaling occurs between tumor and bone, and these signals regulate redundant and overlapping pathways that contribute to tumor growth at the metastatic site." . . . . _:b511900808 . _:b20071542 "Dasatinib has been shown to be an inhibitor of osteoclast function in vitro [47] and in vivo [>>48<<] and in our studies, dasatinib alone did preserve bone structure (Fig." . _:b20071488 . _:b511900799 . . _:b20071545 . . _:b511900828 . _:b511900797 . _:b20071530 "discussion" . _:b20071532 "Examples of tumor/microenvironment interactions are the importance of Src family members activated in PCa [>>40<<], [41] in tumor growth and progression, as well as the importance of Src in osteoclast function [39]; thus, Src targeting affects both the tumor and microenvironment." . . _:b511900796 . _:b20071524 _:b20071525 . _:b20071524 _:b20071526 . _:b20071524 _:b20071527 . _:b511900799 . _:b20071514 "PC3-MM2 [28] and PC3-LG cells [>>29<<] were kindly provided by Dr. Isaiah Fidler (The University of Texas MD Anderson Cancer Center)." . _:b511900797 . _:b511900798 . _:b20071524 _:b20071528 . _:b20071540 "Since dasatinib alone did not produce a notable phenotype in our models, its combination with BMS-754807 by definition enhances its effects rather than showing synergy [>>46<<]." . _:b20071524 _:b20071529 . _:b20071510 . _:b20071538 "We demonstrated that silencing of IGF-1R affected proliferation and cell survival, in agreement with previous findings using monoclonal antibodies against IGF-1R [>>22<<], and was significantly enhanced with the addition of the SFK inhibitor dasatinib." . _:b20071530 _:b20071532 . _:b20071530 _:b20071533 . _:b20071538 . _:b20071533 . _:b20071530 _:b20071534 . . _:b20071530 _:b20071535 . _:b20071530 _:b20071531 . _:b20071509 . _:b511900805 . . _:b20071486 . _:b20071507 "Activating Src and IGF-1R also activates Akt, a key effector of the PI3K/Akt/mTOR pathway, which is aberrantly activated in the majority of malignancies, promoting cell growth, proliferation, and survival [>>24<<], [25].However, whether these inhibitors are equally effective in inhibiting Akt1, 2, and 3 functions is not known, and if combining them produced better results in inhibiting this survival pathway was a goal of this work. Here, we" . _:b20071530 _:b20071548 . _:b511900804 . _:b20071481 "introduction" . _:b20071530 _:b20071544 . _:b20071517 "Fifty microliters of HBSS containing PC3-LG (total, 5\u00D7105 cells) was orthotopically injected as described previously [>>31<<] into a lateral lobe of the prostate." . _:b511900807 . _:b20071530 _:b20071545 . _:b20071530 _:b20071546 . _:b20071530 _:b20071547 . _:b20071528 . _:b20071530 _:b20071540 . _:b511900806 . _:b20071530 _:b20071541 . _:b20071530 _:b20071542 . _:b20071530 _:b20071543 . _:b20071530 _:b20071536 . _:b511900801 . _:b20071522 "H&E and TUNEL staining were performed on MDA PCa 133 xenograft tumors after explantation as described previously [>>36<<], [37]. In each group, 5 different high-power fields (HPF) were examined, the number of TUNEL-positive cells was counted, and the average number of TUNEL-positive cells/HPF was calculated." . _:b20071530 _:b20071537 . _:b20071530 _:b20071538 . . . . _:b20071530 _:b20071539 . . . _:b511900800 . _:b20071496 . _:b511900796 . _:b511900803 . _:b511900797 . _:b511900798 . _:b511900799 . _:b20071528 "Dasatinib alone has been shown to induce osteoblast maturation [>>38<<]; thus possibly increasing RANKL secretion, which in turn normally activates osteoclasts." . _:b511900802 . _:b511900804 . _:b511900813 . _:b511900805 . . _:b511900806 . _:b511900807 . _:b511900806 . _:b511900800 . . _:b511900812 . _:b511900801 . . _:b511900802 . _:b511900803 . . _:b511900812 . _:b511900815 . _:b511900813 . _:b20071495 "Analyses of the phase 1/2 trial indicate SFK inhibition plus docetaxel did not produce meaningful clinical responses in a majority of patients, but were extremely promising for a subset of patients [>>13<<]. Thus, identifying additional signaling pathways that contribute to the metastatic growth of PCa and may augment the effects of Src inhibition is likely to yield promising combinations of inhibitors that will be more efficacious for" . _:b511900814 . _:b20071527 . _:b511900815 . _:b511900808 . _:b511900814 . _:b511900809 . _:b511900810 . _:b511900811 . _:b511900820 . _:b511900809 . _:b511900821 . _:b511900822 . _:b511900823 . . _:b511900816 . _:b20071502 . _:b511900808 . _:b511900817 . _:b511900818 . _:b511900819 . _:b511900828 . _:b511900811 . . _:b20071531 . . _:b20071544 . _:b511900824 . _:b511900810 . _:b511900825 . _:b511900796 . _:b20071522 . _:b511900826 . _:b20071486 "For minimally symptomatic metastatic CRPC, a randomized phase 3 trial showed survival advantage with the vaccine Sipuleucel-T [>>5<<].Thus, while promising agents are improving survival of PCa patients, additional therapeutic agents are clearly needed for advanced stage disease [6]." . _:b511900827 . _:b20071491 "Thus, Src inhibitors block, in part, tumor/microenvironment interactions that lead to the \u201Cvicious cycle\u201D of bone metastasis [>>10<<]. In studies using in vivo orthotopic mouse experiments, inhibition of SFKs decreased both prostate tumor growth and development of lymph node metastases [11]. Based in part on these findings and some promising results from a phase 1/2" . _:b511900821 . _:b511900805 . _:b20071541 "Dasatinib has been shown to be an inhibitor of osteoclast function in vitro [>>47<<] and in vivo [48] and in our studies, dasatinib alone did preserve bone structure (Fig." . _:b20071501 "IGF-1R signaling has been linked to PCa risk, and one of its ligands, IGF-2, is also overexpressed in PCa bone metastases [16], where it promotes proliferation and survival of PCa cells [17], [18], [>>19<<], [20], [21]." . _:b511900820 . _:b20071487 . "10.1371%2Fjournal.pone.0051189" . _:b511900823 . _:b511900817 . . _:b511900822 . _:b511900817 . _:b20071546 . _:b511900816 . _:b511900819 . . _:b511900818 . . _:b20071516 "Intraprostatic injection of luciferase-expressing PC3-LG cells was done as previously published by our group [>>31<<]. Briefly, 40 Swiss nu-nu/Ncr nude mice (8\u201312 weeks old) were anesthetized with 2% isoflurane in an isoflurane-oxygen chamber and then placed in a supine position." . . _:b511900828 . . . _:b20071499 . _:b20071512 "They represent both adeno- and small-cell variants of PCa [>>27<<]. PC3-MM2 [28] and PC3-LG cells [29] were kindly provided by Dr." . _:b20071482 "Metastatic prostate cancer (PCa) accounts for an estimated 28,000 deaths in 2012 [>>1<<]. In advanced, castrate-resistant metastatic PCa (CRPC), few treatment options exist." . _:b20071509 "Here, we examined the individual and combined effects of dasatinib, an SFK inhibitor, and BMS-754807, a potent and reversible small molecule inhibitor of IGF-1R [>>26<<] and the insulin receptor (IR) with activity against various solid tumors in vitro as well as in multiple xenograft models [26]." . _:b511900825 . _:b20071483 "There are only 3 FDA-approved chemotherapeutic agents for CRPC: docetaxel and cabazitaxel [>>2<<], [3], both of which show only a modest survival advantage for men with CRPC, and more recently, the CYP17 inhibitor abiraterone acetate, approved for use after docetaxel failure (ClinicalTrials." . . _:b511900824 . _:b20071539 "Similarly to shRNA-mediated knockdown of IGF-1R, BMS-754807 affected proliferation and increased apoptosis, whereas shRNA to SRC had less effect on proliferation, as demonstrated previously [>>11<<]. These results suggest that Src and IGF-1R regulate overlapping pathways and their combined inhibition may be more effective than inhibiting either kinase alone in treating PCa cells, especially when IGF-1 is abundant, such as in bone" . _:b511900825 . _:b511900827 .