Abstract LB-327: Restoration of MYC-repressed miR-29 in pancreatic cancer cells leads to increased reactive oxygen species and gemcitabine sensitization

Abstract

Pancreatic ductal adenocarcinoma (PDAC) still remains to be one of the most highly malignant human diseases and is resistant to the majority of current therapeutic modalities. Oncogene MYC has been known to be upregulated in PDAC and plays a key role in carcinogenesis and tumor progression. In our previous work, we found the downregulation of miR-29 is a common phenomenon of PDAC, and its restored expression reduced cancer cell migration/invasive potential, anchorage independent growth, and sensitized them to gemcitabine. Furthermore, we showed that miR-29 blocks autophagy in cancer cells by targeting key autophagy related proteins. However, the mechanism associated with the loss of miR-29 in PDAC has yet to be elucidated. Here we demonstrate that MYC inhibits miR-29 expression in PDAC. MYC nuclear localization negatively correlates with miR-29 expression in various pancreatic cancer cell lines, and knockdown of MYC led to an increased expression of both primary miR-29a/b1 transcript and mature miR-29a. Furthermore, miR-29 overexpression in combination with gemcitabine led to decreased cancer cell viability and increased intracellular reactive oxygen species (ROS) and cell death. Our findings show for the first time that MYC represses miR-29 in PDAC, and miR-29 sensitizes pancreatic cancer cells to gemcitabine through increased intracellular ROS. Taken together our results, indicating the potential use of miR-29a as a novel therapeutic agent for PDAC. Citation Format: Jason J. Kwon, Kayla Quirin, Arafat Aljoufi, Amira Nafiseh, Janaiah Kota. Restoration of MYC-repressed miR-29 in pancreatic cancer cells leads to increased reactive oxygen species and gemcitabine sensitization [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr LB-327. doi:10.1158/1538-7445.AM2017-LB-327

Application values of miR-194 and miR-29 in the diagnosis and prognosis of gastric cancer

“…MYC can reduce the expression level of miR-29 in pancreatic ductal adenocarcinoma (PDAC), increase the degree of malignancy, and MYC knockout can upregulate the level of miR-29 expression in PDAC, to increase sensitivity of the tumor to gemcitabine ( 15 ). Low expression level of miR-29 was also detected in other tumors such as head and neck squamous cell carcinoma, and prostate cancer ( 16 , 17 ).…”