Abstract 2317: Palbociclib monotherapy exhibits potent activity in cervical cancer cell lines

Background: Over the last decades, little progress has been made in the systemic treatment of patients with advanced or recurrent cervical cancer. We recently performed an silico analysis to identify potential driver pathways of cervical carcinogenesis and candidate targets for treatment.1 Expression2Kinases (E2K) analysis revealed a protein-protein interaction (PPI) network of 162 nodes (including 20 druggable kinases) consisting of 5 signaling modules associated with MYC signaling (module 1), cell cycle deregulation and cyclin signaling (module 2), TGFβ-signaling (module 3), a PI3K - MAPK signaling (module 4) and chromatine modeling (module 5). Methods: The cervical cancer cell lines included in the study were CaSki, SiHa and HeLa. Cells were incubated for 24 or 72 hours with the PI3K pathway inhibitor BYL719 (Novartis), the multiple pathway inhibitor INC280 (inhibits cMET-dependent PI3K and RAS signaling, Novartis), or the CDK4/6 inhibitor PD-0332991 (palbociclib, Selleck Chemicals) in monotherapy. Sensitivity to drug treatment (0 - 10 μM) was investigated using the colorimetric sulforhodamine B (SRB) assay. IC50 values were calculated using WinNonlin Software. Results: Incubation with BYL719 or INC280 for 24 or 72 hours in concentrations up to 10 μM was not able to establish a distinct cytotoxic effect in the three cervical cancer cell lines included in the study. Incubation with 10 μM BYL719 for 72h resulted in only 20% cell kill, while 10 μM INC280 for 72h caused around 30% cell kill in all three cell lines. However, incubation with palbociclib for 72 hours clearly induced a concentration-dependent cytotoxic effect, with IC50 values of 5.32 ± 0.03 μM, 7.69 ± 0.02 μM and 5.68 ± 0.12 μM for HeLa, SiHa and CaSki cells, respectively. Conclusion: CDK4/6 inhibition seems effective in cervical cancer cell lines and should be further evaluated alone and in combination with chemotherapy for the treatment of advanced and recurrent cervical cancer. References: Van Dam P, van Dam PJ, Rolfo C, Giallombardo M, Van Berckelaer C, Trin XB, Altintas S, Huizing M, Papadimitriou K, Tjalma W, Van Laere S. In silico pathway analysis in cervical carcinoma reveals potential new targets for treatment. Oncotarget 2016;7(3):2780-2795 Citation Format: Peter Van Dam, An Wouters, Luc Dirix, Christian Rolfo. Palbociclib monotherapy exhibits potent activity in cervical cancer cell lines [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 2317.