Cancer-associated fibroblasts enhance pancreatic cancer cell invasion by remodeling the metabolic conversion mechanism

Oncol Rep. 2017 Apr;37(4):1971-1979. doi: 10.3892/or.2017.5479. Epub 2017 Feb 28.

Abstract

We investigated the mechanism of cancer-associated fibroblasts (CAFs) in promoting the invasion and metastasis of pancreatic cancer cells in a non-vascular manner. We verified the original generation of isolated cultured CAFs and normal fibroblasts (NFs) based on the expression of α-SMA and vimentin, and we examined the cell glycolysis level through glucose consumption and lactate production experiments. The mRNA and protein expression of CAF glycolytic enzymes, lactate dehydrogenase and pyruvate kinase m2, were examined by RT-PCR and western blotting, respectively. In vitro culture first-generation pancreatic CAFs were collected and cultured together with pancreas cancer BxPc-3 and Panc-1 cells. Cell invasion and migration were assessed using a Transwell assay and scratch test, respectively. Mitochondrial activity was assessed by experimentally determining oxidative phosphorylation (OP) activity. The aerobic oxidation index of cancer cells was also examined. Succinate dehydrogenase, fumarate hydratase (FH), and monocarboxylate transporter 1 (MCT1) expression were examined using an MCT1-specific inhibitor to remove 'tumor-stromal' metabolic coupling to observe the influence of cell interstices on pancreas cancer progression. First-generation isolated cultured CAFs and NFs both grew well, and showed active proliferation. Glucose absorption and lactate production were significantly enhanced in CAFs compared with that in NFs. PCR and western blotting showed that the lactate dehydrogenase and pyruvate kinase m2 mRNA and protein expression levels were increased in the CAFs. After indirect co-culture, OP was increased in the BxPc-3 and Panc-1 cells; correspondingly, succinate dehydrogenase, FH and MCT expression were increased. After the MCT1-specific inhibitor removed 'tumor-stromal' metabolic coupling, the migration and invasion abilities of the pancreatic cancer cells were decreased. Pancreatic CAFs can alter metabolism as well as communicate with and respond to cancer cell migration and invasion. This may be an important mechanism for promoting tumor progression in a non-vascular manner in the tumor microenvironment. The mechanism by which CAFs reshape metabolic transition requires further analysis.

MeSH terms

  • Actins / biosynthesis
  • Actins / genetics
  • Cancer-Associated Fibroblasts / enzymology
  • Cancer-Associated Fibroblasts / pathology
  • Cell Adhesion / genetics
  • Cell Cycle Proteins / biosynthesis*
  • Cell Cycle Proteins / genetics
  • Cell Line, Tumor
  • Cell Movement / genetics
  • Cell Proliferation / genetics
  • Fumarate Hydratase / biosynthesis*
  • Fumarate Hydratase / genetics
  • Gene Expression Regulation, Neoplastic
  • Humans
  • Neoplasm Invasiveness / genetics
  • Oncogene Proteins / biosynthesis*
  • Oncogene Proteins / genetics
  • Oxidative Phosphorylation
  • Pancreatic Neoplasms / enzymology
  • Pancreatic Neoplasms / genetics*
  • Pancreatic Neoplasms / pathology
  • Succinate Dehydrogenase / biosynthesis*
  • Succinate Dehydrogenase / genetics
  • Tumor Microenvironment / genetics
  • Vimentin / biosynthesis

Substances

  • ACTA2 protein, human
  • Actins
  • Cell Cycle Proteins
  • MCTS1 protein, human
  • Oncogene Proteins
  • Vimentin
  • Succinate Dehydrogenase
  • Fumarate Hydratase