Mint3 depletion restricts tumor malignancy of pancreatic cancer cells by decreasing SKP2 expression via HIF-1

Oncogene. 2020 Sep;39(39):6218-6230. doi: 10.1038/s41388-020-01423-8. Epub 2020 Aug 21.

Abstract

Pancreatic cancer is one of the most fatal cancers without druggable molecular targets. Hypoxia inducible factor-1 (HIF-1) is a heterodimeric transcriptional factor that promotes malignancy in various cancers including pancreatic cancer. Herein, we found that HIF-1 is accumulated in normoxic or moderate hypoxic areas of pancreatic cancer xenografts in vivo and is active even during normoxia in pancreatic cancer cells in vitro. This prompted us to analyze whether the HIF-1 activator Mint3 contributes to malignant features of pancreatic cancer. Mint3 depletion by shRNAs attenuated HIF-1 activity during normoxia and cell proliferation concomitantly with accumulated p21 and p27 protein in pancreatic cancer cells. Further analyses revealed that Mint3 increased transcription of the oncogenic ubiquitin ligase SKP2 in pancreatic cancer cells via HIF-1. This Mint3-HIF-1-SKP2 axis also promoted partial epithelial-mesenchymal transition, stemness features, and chemoresistance in pancreatic cancer cells. Even in vivo, Mint3 depletion attenuated tumor growth of orthotopically inoculated human pancreatic cancer AsPC-1 cells. Database and tissue microarray analyses showed that Mint3 expression is correlated with SKP2 expression in human pancreatic cancer specimens and high Mint3 expression is correlated with poor prognosis of pancreatic cancer patients. Thus, targeting Mint3 may be useful for attenuating the malignant features of pancreatic cancer.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adaptor Proteins, Signal Transducing / genetics
  • Adaptor Proteins, Signal Transducing / metabolism*
  • Cell Proliferation / physiology
  • Cyclin-Dependent Kinase Inhibitor p21 / metabolism
  • Cyclin-Dependent Kinase Inhibitor p27 / metabolism
  • Humans
  • Hypoxia-Inducible Factor 1 / metabolism*
  • Pancreatic Neoplasms / genetics
  • Pancreatic Neoplasms / metabolism*
  • Pancreatic Neoplasms / pathology
  • RNA, Messenger / genetics
  • RNA, Messenger / metabolism
  • S-Phase Kinase-Associated Proteins / biosynthesis*
  • S-Phase Kinase-Associated Proteins / metabolism

Substances

  • APBA3 protein, human
  • Adaptor Proteins, Signal Transducing
  • CDKN1A protein, human
  • CDKN1B protein, human
  • Cyclin-Dependent Kinase Inhibitor p21
  • Hypoxia-Inducible Factor 1
  • RNA, Messenger
  • S-Phase Kinase-Associated Proteins
  • SKP2 protein, human
  • Cyclin-Dependent Kinase Inhibitor p27