Epithelial ovarian cancer (EOC) has an exceedingly high mortality rate. Patients often are in the advanced stages of the disease at diagnosis due to lack of noticeable symptoms, and one of the first symptoms that patients present with is ascites. Ascites is a build-up of fluid in the peritoneal cavity due to loss of balance between fluid drainage and retention caused by leakiness of the peritoneal membrane. Ascitic fluid contains a mixture of different growth factors and cytokines which have the potential to change cell behaviour and correlate with survival, malignancy and efficacy of anti-cancer drugs.

This study is interested in the effect that ascites has on the protein expression and post translational phosphorylation of ovarian cancer cells, both monolayer experiments and a more biologically relevant model using 3D non-adherent cell cluster cultures were run to confirm results were due to ascites treatment and not culture method. Murine ovarian cancer cell line ID8 cultured as both 3D cell aggregates and 2D monolayers were treated with ascites, the cell morphology, proliferation, proteins expressed and levels of phosphorylation for tyrosine and serine residues were compared to a control using methods such as 1D SDS-PAGE, western blot, and MALDI-TOF MS.

We found that human high-grade serous ovarian cancer patient-derived ascitic fluid treatment has a significant effect on EOC model ID8 cell survival, and protein expression within floating cell clusters. Additionally, proliferation was significantly increased within cell monolayers. Protein expression change is potentially due to overexpression of glycolytic enzymes phosphoglycerate kinase 1 and alpha enolase, suggesting that constituents within ascitic fluid may act to trigger the Warburg effect commonly seen in cancer tumours. Later stage (more metastasised) ovarian cancer patient-derived ascites was suggested to favour an increase to ID8 cell cluster malignancy. Future studies are needed to determine the significance of MALDI-TOF MS findings within this experiment to determine the biological relevance to the population of human ovarian cancer patients as a whole.