Cancer associated fibroblasts are distinguishable from peri-tumor fibroblasts by biological characteristics in TSCC

The aim of the present study was to investigate the differential biological characteristics between cancer-associated fibroblasts (CAFs) and peri-tumor fibroblasts (PTFs) in tongue squamous cell carcinoma (TSCC). The primary CAFs and PTFs from TSCC were obtained and purified. Cell morphology was observed, and the expression of α-smooth muscle actin (α-SMA), vimentin and cytokeratin 19 (CK19) was detected by immunohistochemistry (IHC). The percentage of α-SMA positive cells in CAFs and PTFs was calculated separately, and α-SMA expression was further confirmed by western blot analysis. Cell viability and the expression of matrix metalloproteinase 2 (MMP2), stromal cell derived factor1 (SDF-1) and transforming growth factor β1 (TGFβ1) in the purified fibroblasts was detected separately. CAFs and PTFs were attained and purified. Compared with PTFs, CAFs were long-fusiform shaped cells with reduced cytoplasm and variable size. CAFs crowded together in a disorderly manner when the cell density was increased, but this phenomenon did not occur with PTFs. IHC results verified that there was no significant difference between CAFs and PTFs in the percentage of cells staining positive for CK19 and vimentin (P>0.05); the percentage of positive staining cells for α-SMA in CAFs was significantly higher compared with that in PTFs (P<0.001) Western blot analysis showed that α-SMA expression in CAFs was 4.3-fold higher compared with that in PTFs (P<0.001). A Cell Counting Kit-8 assay indicated that the viability of CAFs increased significantly compared with that in the PTFs (P<0.05). Reverse transcription-quantitative polymerase chain reaction and ELISA analysis showed that the expression of MMP2, SDF-1 and TGF β1 in CAFs was higher compared with that in PTFs (P<0.05). CAFs are distinguishable from PTFs with respect to their morphology, cellular phenotype, cell viability and pro-carcinogenic cytokine expression.