Targeted Inhibition of FAK, PYK2 and BCL-XL Synergistically Enhances Apoptosis in Ovarian Clear Cell Carcinoma Cell Lines

Abstract

Ovarian clear cell carcinoma (OCCC) displays a higher resistance to first line chemotherapy, requiring the development of new therapeutics. We previously identified a frequent chromosomal gain at 8q24 that harbors the focal-adhesion kinase (FAK) gene; the potential of this gene as a therapeutic target remains to be evaluated in OCCCs. We first examined the dependence of OCCCs on FAK and the PI3K/AKT signaling pathway. FAK was overexpressed in 20% of 67 OCCC samples, and this overexpression was correlated with its copy number gain. FAK copy number gains and mutations in PIK3CA accounted for about 40% of OCCC samples, suggesting that the FAK/PI3K/AKT axis is an attractive candidate for targeted therapeutics. We, therefore, treated ovarian cancer cell lines, including OCCC subtypes, with the FAK inhibitors PF-562,271 (PF271), and PF-573,228 (PF228). Ovarian cancer cells were more sensitive to PF271 than PF228. We then searched for single agents that exhibited a synergistic effect on cell death in combination with PF271. We found that co-treatment of PF271 with ABT-737, a BCL-2/BCL-XL antagonist, was profoundly effective at inducing apoptosis. RMGI and OVISE cells were more sensitive to ABT-737 than OVMANA and SKOV3 cells, which have PIK3CA mutations. Mechanistically, PF271 treatment resulted in the transient down-regulation of the anti-apoptotic protein MCL1 via the PI3K/AKT pathway. Therefore, PF271/ABT-737 treatment led to the inhibition of the anti-apoptotic proteins MCL1 and BCL-XL/BCL-2. We suggest that pharmacological inhibition of BCL-XL and FAK/PYK2 can be a potential therapeutic strategy for the treatment of OCCC.

Trpm2 enhances physiological bioenergetics and protects against pathological oxidative cardiac injury: Role of Pyk2 phosphorylation

“…activates Pyk2 and amplifies prosurvival ERK signaling in human U937 cells (Yamamoto et al, 2008); (d) pPyk2 activates c-Jun N-terminal kinase and reduces apoptosis in neonatal cardiomyocytes (Dougherty et al, 2004); (e) Pyk2 is prosurvival as evidenced by its overexpression in many cancers (Lipinski & Loftus, 2010); and (f) Pyk2 inhibition decreases survival and proliferation of small cell lung cancer (Roelle, Grosse, Buech, Chubanov, & Gudermann, 2008), breast cancer (Wendt et al, 2013), ovarian clear cell cancer (Yoon et al, 2014), multiple myeloma (Y. Zhang et al, 2014), and prostate cancer (Hsiao et al, 2016).…”

Targeting non-receptor tyrosine kinases using small molecule inhibitors: an overview of recent advances

“…Focal adhesion kinase (FAK) (PTK2) regulates several intracellular activities involved in cell motility, reorganization of actin, cell migration, adhesion, spreading and cell polarization, bone remodeling and transcriptional events promoting epithelial-to-mesenchymal transition (EMT) [73][74][75]. This nRTK is necessary for retention of marginal-zone B cells in the spleen, migration of B cells located in the spleen and macrophage polarization and migration towards sites of inflammation.…”

“…Several studies have noted that FAK overexpression is associated with cancer poor prognosis and drug resistance [73,76]. This nRTK is dysregulated and overexpressed in several cancers such as ovarian [76], skin and breast cancers [77].…”

The effects of focal adhesion kinase on the motility, proliferation and apoptosis of Caco2 and SMMC-7721 cells

“…A good understanding of basic factors and steps required for tumor detection is paramount for effective diagnosis and prognosis of cancers. FAK is ubiquitously overexpressed in a number of human malignancies [22][23][24]. In this study, we constructed plasmids containing siRNA that targeted FAK gene and transfected into Caco2 and SMMC-7721 cells.…”

“…Phosphatase and tensin homolog protein inhibit gastric cancer cell growth and invasion via the down-regulation of FAK expression and suggest FAK might be participate in the PTEN/PI3 K/NF-jB signaling pathway [23]. Numerous studies proved that knockdown of FAK may have effect on the downstream of FAK-PI3 K-Akt [22] and FAK-RAS-Raf-ERK [24,28] pathways. In summary, the results of our study indicated that FAK overexpression significantly enhances the cell growth and inhibits apoptosis in Caco2 and SMMC-7721 cells, and the inhibition of FAK expression causes the cell growth suppression and apoptosis enhancement.…”