Stress granules affect the dual PI3K/mTOR inhibitor response by regulating the mitochondrial unfolded protein response

Abstract Drug resistance remains a challenge in ovarian cancer. In addition to aberrant activation of relevant signaling pathways, the adaptive stress response is emerging as a new spotlight of drug resistance in cancer cells. Stress granules (SGs) are one of the most important features of the adaptive stress response, and there is increasing evidence that SGs promote drug resistance in cancer cells. In the present study, we compared two types of ovarian cancer cells, A2780 and SKOV3, using the dual PI3K/mTOR inhibitor, PKI-402. We found that SGs were formed and SGs could intercept the signaling factor ATF5 and regulate the response of mitochondrial unfolded protein(mtUPR)in A2780 cells. Therefore, exploring the network formed between SGs and membrane-bound organelles, such as mitochondria, may provide new insight into the mechanisms of action of antitumor drugs.