Expression And Significance Of HTERT、SP1and C-MYC In Islet β Cell Tumors And The INS-1Under VCR Intervention

Objective To explore the expression of hTERT, Sp1and c-myc in the organization of islet cell tumor in benign and malignant tumor and normal pancreatic islet cells, and investigate the correlation between hTERT, Sp1and c-myc and islet cell tumor, identifying benign and malignant islet tumor and providing theoretic basis for the prognosis of islet cells; Observe the effect of the antitumor drugs(Vincristine, VCR) on the proliferation,invasion and hTERT, Spl, c-myc expression of rat islet beta tumor cell lines (INS-1cell), and explor its mechanism.Methods The expression of hTERT, Sp1and c-myc were detected by immunohistochemistry in islet cell tumor and normal pancreatic islet cells, and correlation analysis is carried out according to the data; The INS-1cells were divided into two groups which are the control group (no Vincristine) and the experimental group (concentration for0.008mg/ml,0.04mg/ml,0.2mg/ml, lmg/ml VCR), and were cultured for48hours, MTT assay was used to examined the inhibition rate of the INS-1proliferation. the invasion ability was tested by Transwell invasion assay. The hTERT, Sp1and c-myc expression in INS-1cells was detected by RT-PCR. Results In the malignant islet cell tumor, the expression rates of hTERT, Sp1and c-my are81.2%,75%,87.5%respectively. By comparison, the expression rates of hTERT, Spl and c-my are respectively25.9%,29.6%,14.8%in benign islet cells. While hTERT, Sp1and c-my have no expression in normal pancreatic cell tissue. The expression differences of hTERT, Sp1and c-myc in benign and malignant islet cell tumor are statistically significant (P<0.05), and the expression of malignant islet cell tumor is significantly higher than that in the benign pancreatic islet cell tumor and normal pancreatic tissue. Furthermore, there is a significant relationship between hTERT, Spl, c-myc(r=0.992�'�r=0.893, P<0.01).The positive expression rate of three antigens in parallel diagnosis of hTERT, Sp1, c-myc was55.8%(24/43cases), the positive expression rate of diagnosed solely with hTERT antigen was46.5%(20/43cases),the positive expression rate of diagnosis of three antigens in parallel is higher than single diagnosis hTERT antigen. Along with the antitumor drugs VCR concentration increased, the growth inhibition rate of INS-1increase gradually (P<0.05), and compared with control group, VCR coule suppress the growth of INS-1. After cultured by Transwell small room for24hours, the number of cell membrane penetration was150.65±4.02in the control group,while was63.26±5.12in the experimental group(P<0.01). Compared with the control group, hTERT, Sp1, c-myc mRNA gene of the experimental group in the INS-1cells weakened gradually With the extension of time (P<0.05).Conclusion The joint inspection of hTERT, Spl and c-myc can be used as a method to identify benign and malignant isle cell tumor. The telomerase activation plays an important role in the growth and invasion of malignant islet cell tumor. The machanism may be that Vincristine can inhibit he expression of Spl, c-myc and hTERT, thus inhibit the telomerase activity of INS-1, and then rein cell proliferation and reduce invasion ability.