Experimental Study On Cancer Stem Cell-Related Markers And The Origin Of Vascular Endothelial Cell In Xenograft Tumor

Objective: To explore the relationship between cancer stem cells (CSCs) and tumor vascular endothelial cells (TVECs) on the basis of the transplanted subcutaneously tumor model borne by nude mice and induced cell-culture system, focus attention on the tumor angiogenesis and the origin of TVECs, and take a further step to investigate the potential or quality that CSCs differentiate to TVECs.Methods:By injecting human cancer cells into nude mice's subcutaneous tissue of axillary fossa to establish three kinds of tumor xenograft model, after 2 weeks, the neoplasms(>1cm in diameter) induced by tumor cell were removed and pathologically dealt with to survey the morphologic changes, as well as the expression of ki-67 in tumor tissue cells was detected to analyze the proliferation of tumor cell; then, endothelial cell markers (CD31,CD34 and CD105,including purified anti-human and anti-mouse antigens) were detected by immunohistochemistry to determine the origin of TVECs in transplanted tumor; further more, by the same way, squamous cell carcinoma stem cell-related markers(CD133,CD44,ESA and E-Cadherin) and liver CSC markers(CD133,CD44,c-kit and CK19) were assayed also; finally, investigated the differentiation-inducing effect of endothelial cell-specific medium on TCA8113 cells, and detected the expression of endothelial cell markers (CD31, CD34 and CD105)in the 3rd and 5th generation cells.Results: Aforementioned 3 kinds of Engrafted tumor can be separated easily from host for observing, measuring and performing biopsies, HE staining confirmed they got similar morphological characteristics of primary cancer. The strong expression of ki-67 in these transplanted tumor cells has some relationship with the strong proliferation and tumorigenicity of primary tumor cells. By immunohistochemical staining, contrary to the expressions of anti-human-antigens (CD31, CD34 and CD105) were negative in heterograft TVECs, positive expressions showed by anti-mouse-antigens (CD31, CD34 and CD105), and besides, the microvessel density presented by anti-mouse CD34 staining was the highest. The expressions of Squamous cell carcinoma stem cell-related markers (CD133, CD44, ESA and E-Cadherin) and liver CSC markers (CD133, CD44, c-kit and CK19) in respective engrafted tumor cells were positive; engrafted tumors of TCA8113 and TCA8113-M1 both got more sharply positive expressions of E-Cadherin and CD133; as well, in the engrafted tumor of BEL-7404, tested relatively strong positive for CD133 and c-kit. Furthermore, in the differentiation-inducing culture medium, TCA8113 cells, with the past of cell generation time, gradually changed to the long-spindle type; the expressions of anti-human-antigens (CD31, CD34 and CD105) were positive both in the 3rd and the 5th generation cells.Conclusions: There might have a variety of cancer stem cell-related markers expressed in engrafted tumor of tongue cancer and liver cancer cell lines in nude mice, but VECs mainly derived from nude mice hosts in this study, and the angiogenesis in engrafted tumors showed evidence of endothelium-dependence. In differentiation-inducing culture medium, CSCs of tongue cancer and liver cancer cell line have the potential to differentiate to VECs.