Objective: This study was designed to evaluate the effect of zhongjiefeng extracts on telomerase activity and apoptosis of implanted human nasopharyngeal carcinoma cell lines in nude mice.
Method: Nude mice with implanted human nasopharyngeal carcinoma cell lines CNE1 and CNE2 were randomly divided into three groups, which were the group of zhong-jiefeng, normal control group, and CTX therapy group. The weight of nude mice and the volume of tumor were regularly measured. After a course of treatment (30 d), tumor tissues were obtained with autopsy, and then they were weighed to calculate the inhibitive rate of the growth of tumor. The changes of ultra micro-structure of NPC cells were observed by transmission electron microscope. Expressions of Bcl-2 and Bax of xenografts were investigated by immunohistochemistry. The apoptosis of CNE1 and CNE2 cells was observed using TUNEL and FACS with PI-staining. The telomerase activity was observed by TRAP-ELISA method.
Result: The zhongjiefeng extracts significantly inhibit the growth of tumor compared to normal control group. The inhibitory rate were 40.8% (P < 0.01) and 46.8% (P < 0.01), respectively. The expression of Bcl-2 was lower (P < 0.01) and the expression of Bax was higher (P < 0.01) in the zhongjiefeng group than that in normal control group. Electron microscopy indicated the typical apoptosis of tumor cells, such as marginal nuclei, chromatin condensation and nuclei fragmentation, and apoptotic bodies. As result of the flow cytometry showed, the exhibition rate of apoptosis of cell in the group treated with zhongjiefeng was higher than that of normal control group (P < 0.01) in G0/G1 phase. Zhongjiefeng arrested cells in G0/G1 phase of the cell cycle. The telomerase activity of zhongjiefeng and CTX group was lower than that of the normal group (P < 0.01).
Conclusion: Zhongjie feng suppressed the growth of tumor in vivo. The anticancer effects of zhongjiefeng were associated with the induction of apoptosis and partly with the suppression of telomerase activity.