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Targeted inhibition of FAK, PYK2 and BCL-XL synergistically enhances apoptosis in ovarian clear cell carcinoma cell lines.

Yoon H, Choi YL, Song JY, Do I, Kang SY, Ko YH, Song S, Kim BG - PLoS ONE (2014)

Bottom Line: 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.Mechanistically, PF271 treatment resulted in the transient down-regulation of the anti-apoptotic protein MCL1 via the PI3K/AKT pathway.

View Article: PubMed Central - PubMed

Affiliation: Institute for Refractory Cancer Research, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.

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.

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FAK inhibitors down-regulate MCL1.A, MCL1 was transiently down-regulated by treatment with PF271 or PF228. RMGI and OVISE cells were incubated in the presence of PF271 or PF228 at 5 µM for RMGI and 10 µM for OVISE. The cells were harvested at the indicated time points and lysed. D indicates the dimethyl sulfoxide (DMSO) vehicle control. Immunoblots were performed for p-FAK, FAK, MCL1, AKT, and p-AKT. B, A proposed schematic model by how the combined pharmacological inhibition of FAK/PYK2 and BCL-XL/BCL-2 induces apoptosis.
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pone-0088587-g006: FAK inhibitors down-regulate MCL1.A, MCL1 was transiently down-regulated by treatment with PF271 or PF228. RMGI and OVISE cells were incubated in the presence of PF271 or PF228 at 5 µM for RMGI and 10 µM for OVISE. The cells were harvested at the indicated time points and lysed. D indicates the dimethyl sulfoxide (DMSO) vehicle control. Immunoblots were performed for p-FAK, FAK, MCL1, AKT, and p-AKT. B, A proposed schematic model by how the combined pharmacological inhibition of FAK/PYK2 and BCL-XL/BCL-2 induces apoptosis.

Mentions: We assumed that PF271 may transiently down-regulate MCL1 through the PI3K/AKT pathway. To test this hypothesis, we performed a time-course experiment. We treated RMGI and OVISE cells with PF271 or PF228 and harvested the cells at 3, 6, and 24 hr after drug treatment. MCL1 was markedly reduced at 3 and 6 hr after PF271 treatment (Fig. 6A). Likewise, the MCL1 level was slightly decreased at 3 hr and recovered at 6 hr after PF228 treatment (Fig. 6A). FAK inhibitors also suppressed AKT phosphorylation, which correlated with MCL1 down-regulation. Therefore, these data suggested that both FAK inhibitors can down-regulate MCL1 transiently through the PI3K/AKT pathway, and PF271 differs from PF228 with respect to the degree and duration of MCL1 reduction.


Targeted inhibition of FAK, PYK2 and BCL-XL synergistically enhances apoptosis in ovarian clear cell carcinoma cell lines.

Yoon H, Choi YL, Song JY, Do I, Kang SY, Ko YH, Song S, Kim BG - PLoS ONE (2014)

FAK inhibitors down-regulate MCL1.A, MCL1 was transiently down-regulated by treatment with PF271 or PF228. RMGI and OVISE cells were incubated in the presence of PF271 or PF228 at 5 µM for RMGI and 10 µM for OVISE. The cells were harvested at the indicated time points and lysed. D indicates the dimethyl sulfoxide (DMSO) vehicle control. Immunoblots were performed for p-FAK, FAK, MCL1, AKT, and p-AKT. B, A proposed schematic model by how the combined pharmacological inhibition of FAK/PYK2 and BCL-XL/BCL-2 induces apoptosis.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3921183&req=5

pone-0088587-g006: FAK inhibitors down-regulate MCL1.A, MCL1 was transiently down-regulated by treatment with PF271 or PF228. RMGI and OVISE cells were incubated in the presence of PF271 or PF228 at 5 µM for RMGI and 10 µM for OVISE. The cells were harvested at the indicated time points and lysed. D indicates the dimethyl sulfoxide (DMSO) vehicle control. Immunoblots were performed for p-FAK, FAK, MCL1, AKT, and p-AKT. B, A proposed schematic model by how the combined pharmacological inhibition of FAK/PYK2 and BCL-XL/BCL-2 induces apoptosis.
Mentions: We assumed that PF271 may transiently down-regulate MCL1 through the PI3K/AKT pathway. To test this hypothesis, we performed a time-course experiment. We treated RMGI and OVISE cells with PF271 or PF228 and harvested the cells at 3, 6, and 24 hr after drug treatment. MCL1 was markedly reduced at 3 and 6 hr after PF271 treatment (Fig. 6A). Likewise, the MCL1 level was slightly decreased at 3 hr and recovered at 6 hr after PF228 treatment (Fig. 6A). FAK inhibitors also suppressed AKT phosphorylation, which correlated with MCL1 down-regulation. Therefore, these data suggested that both FAK inhibitors can down-regulate MCL1 transiently through the PI3K/AKT pathway, and PF271 differs from PF228 with respect to the degree and duration of MCL1 reduction.

Bottom Line: 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.Mechanistically, PF271 treatment resulted in the transient down-regulation of the anti-apoptotic protein MCL1 via the PI3K/AKT pathway.

View Article: PubMed Central - PubMed

Affiliation: Institute for Refractory Cancer Research, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.

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.

Show MeSH
Related in: MedlinePlus