JS-K, a nitric oxide donor, induces autophagy as a complementary mechanism inhibiting ovarian cancer

Background: Ovarian Cancer (OC) is the second most frequent gynecological Cancer and is associated with a poor prognosis because OC progression is often asymptoma-tic and is detected at a late stage. There remains an urgent need for novel targeted therapies to improve clinical outcomes in ovarian Cancer. As a nitric oxide prodrug, JS-K is reported highly cytotoxic to human Cancer cells such as acute myeloid leukemia, multiple myeloma and breast Cancer. This study is aim to investigate the influence of JS-K on proliferation and Apoptosis in ovarian Cancer cells and explored possible autophagy-related mechanisms, which will contribute to future ovarian Cancer therapy and supply theory support that JS-K holds great promise as a novel therapeutic agent against ovarian Cancer.

Methods: The cytotoxicity, extracellular ROS/RNS activity and apoptotic effect of JS-K and indicated inhibitors on ovarian Cancer cells in vitro were evaluated by MTT assay, extracellular ROS/RNS assay, caspases activities assay and western blot. Further Autophagy effect of JS-K and indicated inhibitors were examined by MTT assay, Cell Transfection, immunofluorescence analysis, transmission electron microscopy (TEM) analysis and western blot on ovarian Cancer cells in vitro. In vivo, the BALB/c-nude female mice with SKOV3 ovarian Cancer cells xenograft were used to examine the efficacy of JS-K treatment on tumor growth. PCNA and p62 proteins were analyzed by immunohistochemistry.

Results: In vitro, JS-K inhibited the proliferation of ovarian Cancer cells, induced Apoptosis and cell nucleus shrinkage, enhanced the enzymatic activity of Caspase-3/7/8/9, and significantly increased the production of ROS/RNS in ovarian Cancer A2780 and SKOV3 cells, these effects were attenuated by inhibition of NAC. In addition, JS-K induced autophagy-related proteins and autophagosomes changes in ovarian Cancer A2780 and SKOV3 cells. In vivo, JS-K inhibited tumor growth, decreased p62 protein expression and increased the expression levels of PCNA in xenograft models which were established using SKOV3 ovarian Cancer cells.

Conclusion: Taken together, we demonstrated that ROS/RNS stress-mediated Apoptosis and Autophagy are mechanisms by which SKOV3 cells undergo cell death after treatment with JS-K in vitro. Moreover, JS-K inhibited SKOV3 tumor growth in vivo. An alternative therapeutic approach for triggering cell death in Cancer cells could constitute a useful multimodal therapies for treating ovarian Cancer, which is known for its resistance to apoptosis-inducing drugs.

Apoptosis; Autophagy; JS-K; Ovarian cancer; Reactive oxygen species (ROS).