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

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.

Tumoral microvesicle–activated glycometabolic reprogramming in fibroblasts promotes the progression of oral squamous cell carcinoma

“…Tumor cells transmit signals to force the stromal cells to undergo aerobic glycolysis and produce more metabolites. In turn, tumor cells absorb the metabolites to fight against nutrient withdrawal and satisfy their anabolic requests to match the high proliferation rate (21, 44).…”

“…In most tissues and tumors, circulating lactate is a major source of tricarboxylic acid (TCA) intermediates, and the contribution of glucose to the TCA cycle is mostly through circulating lactate (19). Based on the reverse Warburg effect, stromal cells act as excellent energy suppliers under harsh environmental conditions (20,21).…”

Pyruvate secreted from patient‐derived cancer‐associated fibroblasts supports survival of primary lymphoma cells

“…In the TME of various tumors, humoral factors released from CAF play fundamental roles in tumor metastasis, resistance to chemotherapy, and epithelial-to-mesenchymal transition (EMT). [15][16][17][18][19][20] In malignant lymphoma, we have previously reported that a mouse-derived fibroblastic reticular cell (FRC) line supported lymphoma cells from patient-derived xenograft (PDX) models, indicating that fibroblasts also play many functional roles in the lymphoma microenvironment. 21,22 This report examined how CAF isolated from primary lymphoma samples support primary lymphoma cells in vitro and clarified the components vital for these abilities.…”

Role of the tumor microenvironment in pancreatic cancer

“…Pancreatic stellate cells are a subset of CAFs . CAFs are a major component of pancreatic cancer stroma, derived from different kinds of progenitor cells such as fibroblasts, pancreatic stellate cells, and epithelial, endothelial, and mesenchymal stem cells . CAFs express α‐smooth muscle actin (α‐SMA), a well‐known and reliable marker of CAF, stromal cell‐derived factor‐1α, fibroblast activation protein, and fibroblast specific protein‐1 .…”