Protease inhibition reduces the survival of ovarian tumour cells in vitro more than platinum-based chemotherapy

Intraperitoneal metastasis is the main mode of tumour-progression in ovarian cancer. Tumour-cells detach from the main tumour, form spheroids and disseminate via ascites to metastasize intraperitoneal. Those tumour-cell spheroids form a mikro-mileu, which allows a protection to chemotherapy.

In our previous investigation we demonstrate, that the cleaved 85-kDa Fragment of E-Cadherin leads to abnormal cell polarity and supports the genesis of tumour-cell spheroids. In this study we investigate the potential of protease-inhibitors to disrupt the tumour-cell spheroids and consecutive to decrease tumour-cell viability.

We used primary ascites-derived tumour-cells with high E-Cadherin 85-kDa fragment for in vitro assays. Tumour-spheroids were prepared with 6x10³ ascites-derived tumour-cells on 2 %-agarose coated 96-well plate format. After tumour-cell aggregation, cells were treated either with the protease inhibitor Calpeptin or the protease inhibitor Ritonavir (each 10 and 50µM) in combination with Cisplatin (10µM) for 48h. Cell viability was measured with the CellTiter-Glo 3D-Cell-Viability Assay.

Calpeptin leads to a reduced density of the tumour-spheroids and to reduced tumour-cell viability of 59 % in comparison to the control. Ritonavir leads to a reduced density of the tumour-spheroids and to reduced tumour-cell viability of 81 % in comparison to the control, while Cisplatin solely reduce the tumour-cell viability to 86 %.

In combination of Cisplatin with Ritonavir we could detect reduced tumour-cell viability of 75 % and in combination with Calpeptin reduced tumour-cell viability of 45 %.

Calpeptin and Ritonavir have the potential to disrupt the mikro-mileu of the ovarian tumour cell-spheroids to make the tumour-cells more susceptible to chemotherapy and to reduce the cell-viability.

Publication History

Article published online:
07 October 2020