DIRAS3 induces autophagy and enhances sensitivity to anti-autophagic therapy in KRAS-driven pancreatic and ovarian carcinomas

ABSTRACT

Pancreatic ductal adenocarcinoma (PDAC) and low-grade ovarian cancer (LGSOC) are characterized by the prevalence of KRAS oncogene mutations. DIRAS3 is the first endogenous non-RAS protein that heterodimerizes with RAS, disrupts RAS clustering, blocks RAS signaling, and inhibits cancer cell growth. Here, we found that DIRAS3-mediated KRAS inhibition induces ROS-mediated apoptosis in PDAC and LGSOC cells with KRAS mutations, but not in cells with wild-type KRAS, by downregulating NFE2L2/Nrf2 transcription, reducing antioxidants, and inducing oxidative stress. DIRAS3 also induces cytoprotective macroautophagy/autophagy that may protect mutant KRAS cancer cells from oxidative stress, by inhibiting mutant KRAS, activating the STK11/LKB1-PRKAA/AMPK pathway, increasing lysosomal CDKN1B/p27 localization, and inducing autophagic gene expression. Treatment with chloroquine or the novel dimeric chloroquine analog DC661 significantly enhances DIRAS3-mediated inhibition of mutant KRAS tumor cell growth in vitro and in vivo. Taken together, our study demonstrates that DIRAS3 plays a critical role in regulating mutant KRAS-driven oncogenesis in PDAC and LGSOC.

Abbreviations: AFR: autophagic flux reporter; ATG: autophagy related; CQ: chloroquine; DCFDA: 2’-7’-dichlorodihydrofluorescein diacetate; DIRAS3: DIRAS family GTPase 3; DOX: doxycycline; KRAS: KRAS proto-oncogene, LGSOC: low-grade serous ovarian cancer; MiT/TFE: microphthalmia family of transcription factors; NAC: N-acetylcysteine; PDAC: pancreatic ductal adenocarcinoma; ROS: reactive oxygen species; TFEB: transcription factor EB

KEYWORDS:

• Autophagy
• chloroquine
• DIRAS3
• KRAS
• LGSOC
• PDAC

Acknowledgements

The authors would like to thank members of the Bast laboratory for their discussion and suggestions. Flow cytometry studies were conducted in the Advanced Cytometry & Sorting Facility at South Campus at MD Anderson Cancer Center provided services for Flow cytometry studies. This work was supported by National Cancer Institute R01 CA266187 (RC Bast and Z Lu PIs), the MD Anderson Ovarian SPOREs P50 CA83639 (RC Bast and A Sood PIs) and P50 CA217685 (RC Bast and A Sood PIs), National Cancer Institute, Department of Health and Human Services, the Shared Resources of the MD Anderson CCSG grant NCI P30 CA 16672, the Cancer Prevention Research Institute of Texas RP140429 (RC Bast, PI); and generous donations from the Ann and Henry Zarrow Foundation, The Mossy Foundation, the Roberson Endowment, and Stuart and Gaye Lynn Zarrow. G.B. was supported by a CPRIT Training Award (RP210028), the HERA Ovarian Cancer Foundation, and the Mentored Investigator Award from the Ovarian Cancer Research Alliance.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Supplementary data

Supplemental data for this article can be accessed online at https://doi.org/10.1080/15548627.2023.2299516

Additional information

Funding

The work was supported by the Cancer Prevention and Research Institute of Texas [RP210028]; Cancer Prevention and Research Institute of Texas [RP140429]; National Cancer Institute [P30 CA 16672]; National Cancer Institute [R01 CA266187]; HERA Ovarian Cancer Foundation; MD Anderson Ovarian SPOREs [P50CA83639 and P50CA217685]; Ovarian Cancer Research Alliance [Mentored Investigator Award from].