TKIs against IGF axis thus have a theoretical advantage over MoAbs given the IR cross reactivity (33). OSI-906 is a potent and highly selective inhibitor of IGF-1R, with 14 times greater selectivity for IGF-1R over IR.34 OSI-906 alone did not show significant efficacy in pancreas cancer cell lines and was further evaluated in
other tumor types preclinically (35). IGF-1R pathway has been reported as potential resistance mechanism to EGFR inhibition and it seems logical to expect increased efficacy when an IGF-1R inhibitor is combined with gemcitabine and erolitinib #this website keyword# in pancreas cancer patients. Clinical trials evaluating OSI-906 with gemcitabine and erlotinib combination have yet to be initiated. However, the dosing regimen and toxicity profile of the combination of OSI-906 and erlotinib were reported at 2010 American Society Inhibitors,research,lifescience,medical of Clinical Oncology
Annual Meeting: OSI-906, administered daily at 50mg and 100mg, combined with erlotinib 100mg daily yielded stable disease in 4 out of 7 (57%) patients, including adrenocortical carcinoma, Ewings Inhibitors,research,lifescience,medical sarcoma, chordoma and adenocarcinoma of unknown primary (36). Toxicities included fatigue (31%) gastrointestinal side effects diarrhea (31%) nausea (15%); grade ≥3 hyperglycemia. Hedgehog/smoothened pathway Smoothened (Smo) is a transmembrane receptor with seven domains, and the activity is repressed by Patched (Ptch). The repression is relieved when ligands bind to Ptch or when there is activating mutations in Ptch, leading to increased Inhibitors,research,lifescience,medical transcription and up-regulation of Gli-1 to 3, thereby
modulating cell cycle and adhesion, angiogenesis, and apoptosis. In a comprehensive genomic analysis of pancreas cancers, mutations in at least one Hedgehog (Hh) signaling component has been reported in all samples Inhibitors,research,lifescience,medical analyzed, indicating the importance of Hh pathway in pancreas tumorgenesis (3). In addition, Hh signaling may be an important modulator of tumor-stromal interaction in the disease (37),(38). Preclinically, Olive et al. evaluated IP-926, a Smo inhibitor, with gemcitabine which the combination improved survival of tumor-bearing Idoxuridine mice and reduced metastasis in a transgenic model (39). The anti-cancer effect seems to be related to a decrease in tumor-associated stromal tissue and improve drug delivery by stimulating VEGF-independent angiogenesis. In this study, the tumor-bearing mice eventually adapted to chronic Smo inhibition and became resistant to the treatment, thus raising the importance in identifying potential resistant mechanisms. Hh signaling is also implicated as an important mediator of cancer stem cell (CSC) phenotype in pancreas cancer. Several groups have reported on the cellular markers of CSCs in pancreas cancer and the CSCs may be identified by the co-expression of CS133/CXCR4, or CD44/CD24/ESA.