The primary treatment for advanced epithelial ovarian cancer is surgery combined with chemotherapy. Unfortunately, relapse is common and often associated with resistance to the commonly used drug combinations. The widely used ovarian cancer cell lines are typically poorly documented, and due to extensive passaging may not serve as appropriate models for studying ovarian cancer or predicting tumor behavior in vivo. Thus, alternative approaches are needed.

In this study, primary cell cultures were established from 50 ascitic fluid and tumor samples collected from patients with disseminated ovarian high grade serous carcinoma (HGSC), either at primary operation or interval surgery. Several different cell culture conditions such as adherent, spheroid and 3D form were tested in order to better sustain the heterogeneous characteristics in cell cultures. In addition, a novel cell culture model utilizing feeder cells was optimized to improve the success rate of the primary cell cultures. The resulting primary cell lines were further characterized and analyzed for phenotypic differences as well as malignancy associated features. Finally, high-throughput screening of over 300 small drug molecules was performed with three HGSC primary cell lines and two commercially available ovarian cancer cell lines in the three different culture conditions.

The majority of the successfully maintained HGSC cell lines originated from ascites whereas only a few cell lines could be established from tumor samples. Altogether 58% of the collected patient samples resulted in a stable cell line. Cell line characterization showed that cells originating from patients with identical histological grade, clinical status, and diagnosis display significantly different phenotypes in vitro. Some of the primary cell lines grew only a limited number of passages, whereas others appeared to have an unlimited growth potential. The characterization was performed with protein analysis, qRT-PCR, and ALDEFLUOR™ flow cytometry measurements. Differences in the drug response were seen among the different primary cell lines, but drug responses also depended on growth conditions. Our results indicate that certain pathways are centrally involved in the drug response and that under certain growth conditions HGSC cells are more sensitive to drug treatments than under others. In conclusion, the analyses demonstrate that the primary HGSC cell lines have unique characteristics, which may not be recapitulated with the common ovarian cancer model cell lines. However, targeting of a few specific signaling pathways may provide significant response to most tested cell lines and culture conditions.

Citation Format: Pia Roering, Piia Mikkonen, Katja Kaipio, Kaisa Huhtinen, Johanna Hynninen, Annika Auranen, Evgeny Kulesskiy, Bhagwan Yadav, Tero Aittokallio, Seija Grénman, Krister Wennerberg, Olli Carpén. Characterization of primary high-grade serous ovarian cancer cell lines: Cell line and growth condition specific differences in stem cell marker expression and high-throughput drug screening. [abstract]. In: Proceedings of the AACR Special Conference on Advances in Ovarian Cancer Research: From Concept to Clinic; Sep 18-21, 2013; Miami, FL. Philadelphia (PA): AACR; Clin Cancer Res 2013;19(19 Suppl):Abstract nr B21.