Anderson, Lee A.

Abstract Here, we investigate the potential role of the PARP inhibitor rucaparib (CO-338, formerly known as AG014699 and PF-01367338) for the treatment of sporadic ovarian cancer. We studied the growth inhibitory effects of rucaparib in a panel of 39 ovarian cancer cell lines that were each characterized for mutation and methylation status of BRCA1/2, baseline gene expression signatures, copy number variations of selected genes, PTEN status, and sensitivity to platinum-based chemotherapy. To study interactions with chemotherapy, we used multiple drug effect analyses and assessed apoptosis, DNA fragmentation, and γH2AX formation. Concentration-dependent antiproliferative effects of rucaparib were seen in 26 of 39 (67%) cell lines and were not restricted to cell lines with BRCA1/2 mutations. Low expression of other genes involved in homologous repair (e.g., BCCIP, BRCC3, ATM, RAD51L1), amplification of AURKA or EMSY, and response to platinum-based chemotherapy was associated with sensitivity to rucaparib. Drug interactions with rucaparib were synergistic for topotecan, synergistic, or additive for carboplatin, doxorubicin or paclitaxel, and additive for gemcitabine. Synergy was most pronounced when rucaparib was combined with topotecan, which resulted in enhanced apoptosis, DNA fragmentation, and γH2AX formation. Importantly, rucaparib potentiated chemotherapy independent of its activity as a single agent. PARP inhibition may be a useful therapeutic strategy for a wider range of ovarian cancers bearing deficiencies in the homologous recombination pathway other than just BRCA1/2 mutations. These results support further clinical evaluation of rucaparib either as a single agent or as an adjunct to chemotherapy for the treatment of sporadic ovarian cancer. Mol Cancer Ther; 12(6); 1002–15. ©2013 AACR.

Abstract The recent identification of activating fibroblast growth factor receptor 2 (FGFR2) mutations in endometrial cancer has generated an opportunity for a novel target-based therapy. Here, we explore the therapeutic potential of 2 FGFR inhibitors, the multikinase inhibitor dovitinib (TKI258) and the more selective FGFR inhibitor NVP-BGJ398 for the treatment of endometrial cancer. We examined the effects of both inhibitors on tumor cell growth, FGFR2 signaling, cell cycle, and apoptosis using a panel of 20 molecularly characterized human endometrial cancer cell lines. Anchorage-independent growth was studied using soft agar assays. In vivo studies were conducted using endometrial cancer xenograft models. Cell lines with activating FGFR2 mutations (S252W, N550K) were more sensitive to dovitinib or NVP-BGJ398 when compared with their FGFR2 wild-type counterparts (P = 0.073 and P = 0.021, respectively). Both agents inhibited FGFR2 signaling, induced cell-cycle arrest, and significantly increased apoptosis in FGFR2-mutant lines. In vitro, dovitinib and NVP-BGJ398 were both potent at inhibiting cell growth of FGFR2-mutant endometrial cancer cells, but the activity of dovitinib was less restricted to FGFR2-mutant lines when compared with NVP-BGJ398. In vivo, dovitinib and NVP-BGJ398 significantly inhibited the growth of FGFR2-mutated endometrial cancer xenograft models. In addition, dovitinib showed significant antitumor activity in FGFR2 wild-type endometrial cancer xenograft models including complete tumor regressions in a long-term in vivo study. Dovitinib and NVP-BGJ398 warrant further clinical evaluation in patients with FGFR2-mutated endometrial cancer. Dovitinib may have antitumor activity in endometrial cancer beyond FGFR2-mutated cases and may permit greater flexibility in patient selection. Mol Cancer Ther; 12(5); 632–42. ©2013 AACR.

Abstract Purpose: PD-0332991 is a selective inhibitor of the CDK4/6 kinases with the ability to block retinoblastoma (Rb) phosphorylation in the low nanomolar range. Here we investigate the role of CDK4/6 inhibition in human ovarian cancer. Experimental Design: We examined the effects of PD-0332991 on proliferation, cell-cycle, apoptosis, and Rb phosphorylation using a panel of 40 established human ovarian cancer cell lines. Molecular markers for response prediction, including p16 and Rb, were studied using gene expression profiling, Western blot, and array CGH. Multiple drug effect analysis was used to study interactions with chemotherapeutic drugs. Expression of p16 and Rb was studied using immunohistochemistry in a large clinical cohort of ovarian cancer patients. Results: Concentration-dependent antiproliferative effects of PD-0332991 were seen in all ovarian cancer cell lines, but varied significantly between individual lines. Rb-proficient cell lines with low p16 expression were most responsive to CDK4/6 inhibition. Copy number variations of CDKN2A, RB, CCNE1, and CCND1 were associated with response to PD-0332991. CDK4/6 inhibition induced G0/G1 cell cycle arrest, blocked Rb phosphorylation in a concentration-and time-dependent manner, and enhanced the effects of chemotherapy. Rb-proficiency with low p16 expression was seen in 97/262 (37%) of ovarian cancer patients and was independently associated with poor progression-free survival (adjusted relative risk 1.49, 95% CI 1.00–2.24, P = 0.052). Conclusions: PD-0332991 shows promising biologic activity in ovarian cancer cell lines. Assessment of Rb and p16 expression may help select patients most likely to benefit from CDK4/6 inhibition in ovarian cancer. Clin Cancer Res; 17(6); 1591–602. ©2011 AACR.