Preliminary Study On The Role Of HERG1Protein Expression And OSCC-EPCs Fusion In Tumor Neovascularization

Part1Objective:The aim of this study was to investigate the expression of hERG1protein and its correlation with clinicopathological factors and tumor angiogenesis in oral squamous cell carcinoma(OSCC).Methods:hERG1, VEGF-A expression and MVD were investigated using immunohistochemistry in67OSCC and24normal oral mucosa (NOM) samples. The chi-square test was used to analyze statistically significant differences between hERG1protein expression in clinicopathologic factors. The correlation between hERG1, VEGF-A and MVD were analyzed with Spearman partial rank correlation coefficient. hERG1protein and IhERGiof OSCC cell lines were detected by Western Blot and patch-clamp technique respectively.Results:In24NOM and67OSCC samples, frequency of positive expression of hERG1protein was38.8%(26/67) in OSCC, which is significantly higher than that4.2%(1/24) in NOM. hERG1protein was significantly associated with TNM clinical stage(P<0.05), but not with other clinicopathological factors(P>0.05). There was linear correlation between hERG1, VEGF-A and MVD(P<0.05). hERG1protein and1hERG1were not detected in Tca-8113, GNM, CAL27and SCC-4cells.Conclusions:hERG1potassium channel may play a rote in the malignant transformation of NOM and tumor angiogenesis; hERG1protein is a promising candidate as an early diagnostic and prognostic molecular marker for OSCC patients. Part2Objective:To observe whether vasculogenic mimicry(VM) exist in oral squamous cell carcinoma(OSCC) and late endothelial progenitor cells EPCsflate EPCs) from rat bone marrow can spontaneously fuse with OSCC cells. To investigate whether the fused cells can obtain the phenotypic characteristics of parental cells and participate in tube formation in vitro.Methods:To detect VM in OSCC, sections of tumor tissues were double-stained with CD34immunohistochemical and PAS stain. Late EPCs from rat bone marrow were isolated, cultured and identified. To detect the spontaneous fusion between Late EPCs and SCC-4cells, CM-Dil-labled late EPCs were cocultured with SCC-4cells and then the cells were fixed and stained with Cytokeratin by immunofluorescent method. To investigate whether fused cells can simultaneously express phenotypic characteristics of parental cells, late EPCs and SCC-4cells were cocultured and then the cells were stained by double immunofluorescent with specific markers of late EPCs and SCC-4cells. To investigate whether fused cells can participate in tube formation in vitro, CM-Dil pre-labled late EPCs and SCC-4cells were seeded on matrigel-coated plates and then the cells were stained with cytokeratin.Results:In67OSCC tissues, VM was observed in2(2.99%) samples. SCC-4cells can spontaneously fuse with late EPCs in vitro and the fused cells can simultaneously express phenotypic characteristics of SCC-4cells(Cytokeratin) and late EPCs(CD31). the fused cells can participate in tube formation in vitro.Conclusions:VM rarely exists in OSCC. Tumor cells can spontaneously fuse with late EPCs and the fused cells can obtain phenotypic characteristics of parental cells; The cell fusion of tumor cells and late EPCs may be an underlying mechanisms in VM formation.