Abstract 1100: Synergistic interaction between gemcitabine and PD-0325901 in C-33A cervical carcinoma cell line

Abstract Cervical cancer affects over half a million women worldwide, and is one of the most common causes of death in women. Treatment of cervical cancers consists of surgery, radiation, chemotherapy, or combination of therapies. However, about half of patients with advance cancer will show recurrent tumors. Signaling cascades are often dysregulated in human cancer cells making them attractive targets for combination drug therapies. PD-0325901, an inhibitor of the mitogen-activated protein kinase, is a promising target for metastatic cancer. Another drug used to treat cervical carcinoma is gemcitabine, a nucleoside analog inhibitor of the ribonucleotide reductase and DNA damage inducible protein 45a (Gadd45a). This drug is generally used in combination with other drugs, after reoccurrence of the disease state. We decided to evaluate the efficacy of gemcitabine in combination with PD-0325901 in C-33A, a metastatic cervical cancer-derived cell line. We evaluated the potency of gemcitabine and PD-0325901 alone and in combination. Cell viability after incubation with the drugs was determined at 72 hours and at 7 days by measuring ATP content. Synergy was determined assessed utilizing BIOENSIS’s suite of drug combination analysis tools including: isobologram, combination index (CI) and Bliss analysis. Isobologram analysis at 72 hours of incubation revealed that the mean values of the observed data were significantly smaller than those of the predicted maximum additive values, indicating synergy. Bliss and combination index analysis confirmed the observation, showing a synergistic effect at concentrations between 2 - 200 nM PD-0325901 and 0.3 - 3 nM gemcitabine. Similar patterns of synergy were observed with 7 day incubations of C-33A with gemcitabine and PD-0325901. These results indicate that gemcitabine and PD-0325901 showed significantly more growth inhibition than either drug alone in the C-33A tumor cell line, suggesting that the combination of gemcitabine - PD-0325901 could be used in cervical cancer therapy. Citation Format: Macarena Irigoyen, Gonzalo Castillo. Synergistic interaction between gemcitabine and PD-0325901 in C-33A cervical carcinoma cell line [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 1100. doi:10.1158/1538-7445.AM2017-1100