The FAK scaffold inhibitor C4 disrupts FAK-VEGFR-3 signaling and inhibits pancreatic cancer growth

Abstract

Even with successful surgical resection and perioperative chemotherapy and radiation, pancreatic ductal adenocarcinoma (PDA) has a high incidence of recurrence. Tumor cell survival depends on activation of signaling pathways that suppress the apoptotic stimuli of invasion and metastasis. Focal adhesion kinase (FAK) is a critical signaling molecule that has been implicated in tumor cell survival, invasion and metastasis. We have previously shown that FAK and vascular endothelial growth factor receptor 3 (VEGFR-3) are overexpressed in cancer cells and physically interact to confer a significant survival advantage. We subsequently identified a novel small molecule inhibitor C4 that targeted the VEGFR-3-FAK site of interaction. In this study, we have shown that C4 disrupted the FAK-VEGFR-3 complexes in PDA cells. C4 treatment caused dose-dependent dephosphorylation and inactivation of the VEGFR-3 and FAK, reduction in cell viability and proliferation, cell cycle arrest and apoptosis in PDA cells. C4 increased the sensitivity of tumor cells to gemcitabine chemotherapy in vitro that lead to apoptosis at nanomolar concentrations of both drugs. C4 reduced tumor growth in vivoin subcutaneous and orthotopic murine models of PDA. The drug alone at low dose, decreased tumor growth; however, concomitant administration with low dose of gemcitabine had significant synergistic effect and led to 70% tumor reduction. Combination of C4 with gemcitabine had a prolonged cytostatic effect on tumor growth after treatment withdrawal. Finally, we report an anecdotal case of stage IV pancreatic cancer treated with gemcitabine in combination with C4 that showed a significant clinical response in primary tumor and complete clinical response in liver metastasis over an eight month period. Taken together, these results demonstrate that targeting the scaffolding function of FAK with a small-molecule FAK-VEGFR-3 inhibitor can be an effective therapeutic strategy against PDA.

Combination of carbon ion beam and gemcitabine causes irreparable DNA damage and death of radioresistant pancreatic cancer stem-like cellsin vitroandin vivo

“…It has been demonstrated that gemcitabine radiosensitizes pancreatic cancer cells accompanied with apoptosis and autophagy [36, 44-47]. Gemcitabine has also been shown to induce senescence in pancreatic cancer cells [48].…”

Design, synthesis, and biological evaluation of novel FAK scaffold inhibitors targeting the FAK–VEGFR3 protein–protein interaction

“…A few examples of well characterized protein–protein interaction inhibitors are SP4206 that disrupts the interaction between interleukin 2 (IL-2) and the α-chain of the IL-2 receptor (IL-2Rα) [39], BH3-mimetic ABT-737 [40] which possesses high-affinity binding to the hydrophobic BH3-binding site of recombinant Bcl-X L , ABT-737, and Nutlins that were found to disrupt MDM2–p53 complexes [41]. By inhibiting the interplay between FAK and VEGFR3, we have previously shown that 1 downregulated major FAK and VEGFR3 tyrosine phosphorylation sites that in turn affect key protein signaling networks associated with cancer cell survival, angiogenesis, and metastasis [32,34]. Here, we have discovered that 29 successfully disrupted the FAK–VEGFR3 interaction and induced apoptotic cancer cell death, thus we anticipate 29 to mimic the overall anti-cancer effects of 1 , albeit at much lower concentrations.…”

“…1) which successfully binds and disrupts the FAK–VEGFR3 interaction [31]. Further testing with 1 showed reduction in tumor burden and neovascularization in mouse models of melanoma, breast cancer, pancreatic cancer [32], and glioblastoma.…”

Targeting the C-terminal focal adhesion kinase scaffold in pancreatic cancer

“…Staining procedures were performed as described previously [20]. A positive and negative control was included in each staining.…”