Arsenic trioxide synergizes with everolimus (Rad001) to induce cytotoxicity of ovarian cancer cells through increased autophagy and apoptosis

• Published in: Endocrine-related cancer Vol. 19; no. 5; pp. 711 - 723
• Main Authors: Liu, Nan, Tai, Sheng, Ding, Boxiao, Thor, Ryan K, Bhuta, Sunita, Sun, Yin, Huang, Jiaoti
• Format: Journal Article
• Language: English
• Published: England Society for Endocrinology 01.10.2012
• Subjects: Adaptor Proteins, Signal Transducing - metabolism; Animals; Antineoplastic Agents - administration & dosage; Antineoplastic Combined Chemotherapy Protocols; Apoptosis - drug effects; Arsenicals - administration & dosage; Autophagy - drug effects; Caspase 3 - metabolism; Caspase 7 - metabolism; Cell Line, Tumor; Drug Synergism; Everolimus; Female; Humans; Immunosuppressive Agents - administration & dosage; Mice; Mice, SCID; Ovarian Neoplasms - drug therapy; Ovarian Neoplasms - metabolism; Ovarian Neoplasms - pathology; Oxides - administration & dosage; Phosphoproteins - metabolism; Proto-Oncogene Proteins c-akt - metabolism; Regular papers; Sirolimus - administration & dosage; Sirolimus - analogs & derivatives; Xenograft Model Antitumor Assays
• ISSN: 1351-0088; 1479-6821
• DOI: 10.1530/ERC-12-0150

Phosphatidylinositol 3-kinase/AKT/mammalian target of rapamycin pathway plays a key role in the tumorigenesis of a variety of human cancers including ovarian cancer. However, inhibitors of this pathway such as Rad001 have not shown therapeutic efficacy as a single agent for this cancer. Arsenic trioxide (ATO) induces an autophagic pathway in ovarian carcinoma cells. We found that ATO can synergize with Rad001 to induce cytotoxicity of ovarian cancer cells. Moreover, we identified synergistic induction of autophagy and apoptosis as the likely underlying mechanism that is responsible for the enhanced cytotoxicity. The enhanced cytotoxicity is accompanied by decreased p-AKT levels as well as upregulation of ATG5–ATG12 conjugate and LC3-2, hallmarks of autophagy. Rad001 and ATO can also synergistically inhibit tumors in a xenograft animal model of ovarian cancer. These results thus identify and validate a novel mechanism to enhance and expand the existing targeted therapeutic agent to treat human ovarian cancer.