Effects Of CK13Gene Mediated By Liposome On The Cell Cycle And Apoptosis In Nasopharyngeal Carcinoma Cell Strain HNE1before And After Radiotherapy

Objective:To observe and analyze the effect of CK13gene mediated by liposome on the cell cycle and apoptosis in nasopharyngeal carcinoma xenografts in Nude mice before and after radiotherapy, and study the value of CK13gene in treatment of nasopharyngeal carcinoma.Methods:In this study, the first step was cell culture; the second step was animal experiment. The animal experiments were divided into two groups to conduct.The first large group with four cell lines, namely HNE1-CK13-A、HNE1-CK13-B、HNE1-pEGFP-N1and HNE1, were aimed to establish four groups-A1、B1、O1and H1of animal models (in short, gene group). Each group had eight nude mice. Then We observed their activities and measured the size of the tumor every day. When the tumor grew to about10mm×10mm, four nude mice in each group were killed. Later, We removed the tumor and divided each into two. One was used to observe the pathological type by HE, the other one was used to analyze cell cycle and apoptosis by FCM. On the same day, the remaining four nude mice in each group were irradiated with a dose of two Gy. Two days later, the nude mice were irradiated again in the same circumstances. Twenty four hours after the second irradiation, all remaining nude were killed. Then cell cycle and apoptosis which were exposed to radiotherapy by FCM were analyzed.The second large group with HNE1cell lines was adopted to establish NPC animal models. Later, We observed their activities and measured the size of the tumor every day. When the tumor grew to about10mm×10mm, all nude mice were divided into four groups, namely A2、B2、02and H2at random (in short, plasmid group). Each group had eight nude mice and were injected plasmid of CK13-A、CK13-B、pEGFP-N1and PBS respectively. The next day, four nude mice were chosen in each group at random, than they were irradiated with a dose of two Gy and marked as well. After forty eight hours, four groups were injected plasmid and PBS again. On the second day, all unlabeled mice were killed. Later, We removed the tumor and divided each into two. Among them, one was used to observe the pathological type by HE, the other one was used to analyze cell cycle and apoptosis by FCM. On the same day, the remaining four nude in each group were irradiated again. Twenty four hours later, all remaining nude mice were killed. In addition, the cell cycle and apoptosis which were exposed to radiotherapy by FCM were analyzed.In this way, We observed the effect of CK13gene on cell cycle and apoptosis of the cells in nasopharyngeal carcinoma xenografts, analyzed its changes before and after radiotherapy, provided clues for further research of the mechanism of CK13gene about how to increase radiosensitivity.Results:1. During the experiment, all nude mice had no death, the survival rate was100%. Tumors in the armpits could be seen obviously, and the rate of tumor formation was100%.2. After the radiotherapy, the tumors of group A1、B、 and group A2、B2grew slowly, stopped or even shrank, but no one disappeared. The tumors of group O1、H1and group O2、H2only grew slowly. The comparison of volume had statistical difference(P<0.05).3. After the radiotherapy, the weight of the tumor of group A1、B1and group A2、B2became lighter than group O1、H1and group O2、H2(P<0.05),and the inhibition rate of group A1、B1and group A2、B2became higher.4. The pathologic examination of the tumors in two large groups showed a poorly differentiated squamous cell carcinoma. 5. The number of cells in G2/M phase of the tumors in two large groups after radiotherapy was much more than before(P<0.05), while the number of cells in G2/M phase in group A1、B1and group A2、B2before and after radiotherapy was much more than the number in group O1、H1and group O2、H2(P<0.05), but the increase was obviously after radiotherapy (P<0.05).6. The apoptosis rate of the tumors in two large groups after the radiotherapy was much more than before; but group A1、B1and group A2、B2increased more significantly than group O1、H1and group O2、H2(P<0.05).Conclusion:When CK13gene was combine with radiotherapy, the tumors of nasopharyngeal cell strain HNE1grow slowly, stop or even shrink. CK13gene can regulate the distribution of cell cycle, increasing the number of cells in G2/M phase, and the G2/M phase is a relatively sensitive period to radiotherapy. Compare with the only method of radiotherapy, the apoptosis of the cell of nasopharyngeal after CK13gene combine with radiotherapy can have a higher rate. CK13gene can play the role in inducing apoptosis. CK13gene can increase radiosensitivity of nasopharyngeal carcinoma cell strain HNE1by changing cell cycle and inducing apoptosis. It may become a new and target gene for the treatment of nasopharyngeal carcinoma.