Pim-3 promotes human pancreatic cancer growth by regulating tumor vasculogenesis

Oncol Rep. 2014 Jun;31(6):2625-34. doi: 10.3892/or.2014.3158. Epub 2014 Apr 25.

Abstract

Pim-3, a proto-oncogene with serine/threonine kinase activity, is aberrantly expressed in malignant lesions, but not in normal pancreatic tissues. To assess the role of Pim-3 in human pancreatic carcinogenesis in vivo and to determine the underlying Pim-3 signaling regulatory mechanisms, we established MiaPaca-2 cells overexpressing wild-type Pim-3 or Pim-3 kinase dead mutants (K69M-Pim-3) as well as PCI55 cells stably expressing Pim-3 shRNA or scrambled shRNA in a tetracycline-inducible manner. In addition, we conducted studies utilizing a nude mouse tumor xenograft model. Our results demonstrated that cells stably overexpressing wild-type Pim-3 exhibited functionally enhanced phosphorylation of Bad at Ser112 and increased proliferation. In contrast, the stable inactivation of Pim-3 by K69M-Pim-3 or silencing of Pim-3 expression by Pim-3 shRNA resulted in functionally decreased phosphorylation of Bad at Ser112 and higher apoptotic cells. Following subcutaneous injection of these stable cell lines, nude mice injected with Pim-3 overexpressing cells developed 100% subcutaneous tumors, together with increased PCNA-positive cells and enhanced intratumoral CD31-positive vascular areas. On the other hand, intratumoral neovascularization and tumor cell proliferation was attenuated in mice injected with Pim-3 kinase inactive cells, eventually reducing tumorigenicity in these mice to 46.6%. Moreover, Pim-3 overexpression upregulated the intratumoral levels of pSTAT3Try705, pSurvivinThr34, HGF, EGF, FGF-2 and VEGF, while the increases were markedly diminished on Pim-3 kinase inactivation. Collectively, the Pim-3 kinase emerges as being involved in accelerating human pancreatic cancer development and in promoting tumor neovascularization and subsequent tumor growth. Targeting Pim-3 may play a dual role in halting tumor progression, by promoting tumor cell death and blocking angiogenesis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Apoptosis / genetics
  • Cell Differentiation / genetics
  • Cell Line, Tumor
  • Cell Proliferation / genetics*
  • Gene Expression Regulation, Neoplastic
  • Humans
  • Mice
  • Molecular Targeted Therapy
  • Neovascularization, Pathologic / genetics*
  • Pancreatic Neoplasms / genetics*
  • Pancreatic Neoplasms / pathology
  • Protein Serine-Threonine Kinases / biosynthesis*
  • Protein Serine-Threonine Kinases / genetics
  • Proto-Oncogene Mas
  • Proto-Oncogene Proteins / biosynthesis*
  • Proto-Oncogene Proteins / genetics

Substances

  • MAS1 protein, human
  • Proto-Oncogene Mas
  • Proto-Oncogene Proteins
  • PIM3 protein, human
  • Protein Serine-Threonine Kinases