Inhibition Of Xenograft With Suppressor Gene CCNG2 On The Mude Models Of Thyroid Cancer

Objectives Thyroid cancer(TC) is a common endocrine malignancies, with a steadi ly increasing incidence over the last several decades., which is the first common m alignant tumor in the head and neck. Although the cancer can have a good progno sis and long-term survival rate after standard treatment with surgery and radioactive iodine, but the recurrence of patients or radioactive iodine refractory disease with t he 10 year survival rate is only 15% to 20%. Therefore, the molecular targeted the rapy forthyroid cancer has become an urgent problem to be solved in the medical f ield. Cyclin G2 is a member of the cyclin family, who as a negative factor of cell cycle regulation. Previous studies have reported that cyclin G2 has a variety of fu nctions involved in regulation and tumor progression. The abnormal expression of t he CCNG2 gene can lead to cause the disorder of cell cycle and induce tumor. Ev idences showed that CCNG2 has a obvious expression of decreased in the thyroid papillarycarcinoma. We found that K1 cells transfected with CCNG2 gene the prolif eration and apoptosis of K1 cells increased obviously. In order to further study the CCNG2 overexpression in vivo tumor inhibitory effect, we adopt nude mice xenog raft tumor model, CCNG2 lentiviral expression vector was constructed, using lentivi ral stable transfection techniques enable CCNG2 stable long-term expression in K1 cells, CCNG2 inhibited thyroid cancer in preliminary in vivo experiments.Methods Choosing SPF BALB/C 4 week old female mice. Then separated them into three groups at random: blank control group(K1 cell group), LV-CCNG2 tra nsfected group(LV-CCNG2 cells) and negative negative control group(LV-GFP-Puro cell group), 6 rats in each group. We collected grew well cells injected was resus pended in serum-free culture medium(final concentration of 5 x 107) in nude mice right axillary subcutaneous according to the vaccination group established thyroid c arcinoma xenograft tumor model. The survival state of nude mice was observed an d recorded and tumor nodules, and vernier caliper to measure the tumor of long ax is and short axis calculation of tumor volume, drawing the growth curve. 30 days after breaking the neck to nude mice in all groups were sacrificed and removal of tumor tissue, by immunohistochemistry and Western blot assay of CCNG2, p53 and MDM2 protein were qualitative and quantitative detection, CCNG2 observe the ov er expression of inhibitory effect on tumor.Results 1 The growth of nude mice and transplanted tumor in nude mice and.K1 cell group, LV-CCNG2 cell group, LV-GFP-Puro cell group were inoculated with cell suspension the growth of tumor nodules, the rate of 100%. The weight of nude mice of LV-CCNG2 cell group was significantly larger than that of the o ther two groups, the difference was statistically significant(F=7.112, P <0.005). T here was no significant difference in body weight(P=0.615) between K1 cells an d LV-GFP-Puro cells. 2 The growth curve of subcutaneous transplanted tumor in nude mice. LV-CCNG2 cell xenografts in the nude mice into the delay time of tu mor, tumor size and growth rate slow, average volume is obviously less than that of the cells in group K1 and LV-GFP-Puro cells group(F=54.983, P<0.05), the volume of tumor rate was 67.07%. The volume of tumor tissue formed by cell s uspension inoculated in nude mice was observed at different time and the total vo lume was also different(F=267.128, P <0.05). Compared with K1 cell group and LV-GFP-Puro cell group, there was no significant difference in the growth trendof transplanted tumors(P>0.05). In the initial stage of transfection, the growth rat e of transplanted tumor was significantly decreased, and the growth rate of LV-C CNG2 cells was accelerated after the experiment, but it was still lower than that of K1 cells and LV-GFP-Puro cells. 3 changes in the weight of transplanted tumo rs in nude mice. The average tumor mass in LV-CCNG2 cell group was lower th an that in K1 cell group and LV-GFP-Puro cell group, and the difference was sta tistically significant(P<0.05). There was no significant difference in tumor volume and mean tumor mass between the K1 cell group and the LV-LV-GFP-Puro cell group(P >0.05). 4 Analysis the expression of CCNG2, p53 and MDM2 protein in each groups' transplanted tumor samples by using immunohistochemistry. Th e positive rates of CCNG2, p53 and MDM2 protein in the tumor tissues of LV-C CNG2 cell group were significantly higher than those in the control group and bl ank control group, and the difference was statistically significant(P<0.05). The ex pression of CCNG2, p53 and MDM2 protein in transplanted tumor was not statisti cally significant(P>0.05) compared with K1 cell group and LV-K1-NC cell group.5 The Western blotting test results. The expression levels of CCNG2, P53 and MDM2 in LV-CCNG2 cell group were significantly higher than that in K1 cell gr oup and LV-K1-NC cell group, and the difference was statistically significant(P<0.05). There was no significant difference between the K1 cell group and LV-G FP-Puro cell group(P>0.05).