GCN-5/PGC-1α signaling is activated and associated with metabolism in cyclin E1-driven ovarian cancer.

Aim: We previously found Cyclin E1-driven high grade serous ovarian cancer (HGSOC) showed metabolic shift. In this study, we aimed to elucidate signaling pathway therein. Methods: In silico reproduction of TCGA ovarian cancer dataset and pathway analysis were performed. Candidate metabolic pathway was validated using in vitro and in vivo assays. Results: We found CCNE1-amplified HGSOC showed significant metabolic alteration besides canonical cell cycle control. Using CCNE1-amplified OVCAR-3 and A2780 OvCa cells, we found that knockdown of CDK2 and GCN5 resulted in decreased G6PC and increased PGC-1 alpha level, and that both genetic and pharmaceutical (MB-3) inhibition of GCN5 resulted in significant decrease in acetylation of PGC-1 alpha. Silencing of CDK2 also resulted in significant decrease in acetylation of both PGC-1 alpha and Rb. GCN5-KD significantly decreased glucose uptake, increased lactate production and decreased SDH activity. Western blots showed hierarchy of the elements indicating Cyclin E1-CDK2/GCN5/PGC-1 alpha regulatory axis from up- to down-stream. Inhibitory effect of Dinaciclib was similar to that of GCN5 silencing, whereas combination therapy further inhibited cell proliferation significantly. Similar findings were noted also in cell cycle arrest, apoptosis, invasion, migration and colony formation assays. Xenograft experiments showed that GCN5-KD alone did not alter tumor growth yet combination therapy of Dinaciclib and GCN5-KD conferred significant inhibition of tumor growth compared with either therapy alone with no toxicity observed. Conclusion: GCN-5/PGC-1 alpha signaling is activated and associated with metabolism in Cyclin E1-driven HGSOC. Targeting GCN5 hold promise to augment current CDK2-targeting strategy and further studies are warranted for clinical translation.