The impact of ^(60)Co γ-ray on apoptosis to Hep-2 human laryngeal cancer cell in the condition of reoxygenation after hypoxia

Objective： The aim of the study was to establish models of Hep-2 laryngeal cancer cell line of different oxygen supplying, trying to investigate the impact of normoxia, hypoxia, reoxygenation after hypoxia on apoptosis and expression of proteins HIF-1α and p53 to Hep-2 human laryngeal cancer cell line induced by ^60Co γ-ray. Methods： Human laryngeal cancer Hep-2 cells were divided into 3 groups： group A （normoxia）, group B （hypoxia）, and group C （reoxygenation after hypoxia）. All of the cells were exposed to 5 Gy dosage of γ-ray. Flow cytometry （FCM） was used tomeasure the protein levels of HIF-1α and p53 and to detect cell apoptosis. The protein levels of HIF-la and p53 were also determined by immunohistochemistry and Western blotting. The expression of HIF-la mRNA was determined by RT-PCR. Results： The protein levels of HIF-1α and p53 were evidently increased in group B compared to group A. The protein levels of HIF-1α and p53 in group C were lower compared to group B; the rate of apoptosis in group C was higher than that in group B. Conclusion： Hypoxia decreased the effect of apoptosis induced by ^60Co γ-ray in Hep-2 human laryngeal cancer cell line. The apoptosis pathway maybe related to some other genes or proteins but not p53 in the conditions of hypoxia and reoxygenation after hypoxia.

The impact of ^(60)Co γ-ray on cycles to Hep-2 human laryngeal cancer cell in the condition of hypoxia

Objective： The aim of the study was to investigate the impact of 60Co y-ray on apoptosis, cell cycles and the expression of protein hypoxia-inducible factor-1α （HIF-1α） to Hep-2 cell line in the conditions of normoxia and hypoxia. Methods： Hep-2 cell were divided into 2 groups： group A （normoxia） and group B （hypoxia）. All of the ceils were exposed to y-ray with dosage being 0, 1, 3, 5, 10, 20, and 40 Gy. Flow cytometry was used to measure the protein level of HIF-1α and to detect apoptosis and cell cycles. The protein level of HIF-1α was also determined by immunohistochemistry and Western blotting. Results： The protein level of HIF-1α in group B was significantly higher than that in group A. In group A, low doses （1-5 Gy） of y-ray had caused G0/G1 cell cycle arrest and high doses （10-40 Gy） had caused G2/M cell cycle arrest. In group B, without exposure of y-ray （0 Gy） had caused G0/G1 cell cycle arrest, all of the different dosage of y-ray could cause G2/M cell cycle arrest. The curve of apoptosis rate in group A was a parabola, the apoptotic rate was related to the dosage of y-ray in a dosage dependent manner. The peak was at the point of 5 Gy. The apoptosis rate in group A was significantly higher than that in group B. Conclusion： Different doses of y-ray could cause different cell cycles arrest then make different impact on apoptosis to Hep-2 ceil. The lower apoptosis rate in condition of hypoxia maybe has a relationship with G2/M cell cycle arrest. Up-regulated HIF-1α protein may be one of the reasons for G2/M cell cycle arrest.

天佛参口服液诱导人喉癌Hep-2细胞凋亡及机制探讨

目的 :探讨天佛参口服液诱导人喉癌 Hep- 2细胞凋亡及其机制。方法 :采用体外细胞培养实验方法。应用 MTT、透射电镜、DNA琼脂糖凝胶电泳、流式细胞仪检测、原位末端标记等技术 ,观察药物对细胞的抑制率及凋亡形态 ,检测凋亡率及胞内 [Ca2 +]变化。结果 :MTT测得细胞抑制率随时间、剂量而增大 ,透射电镜下见到凋亡细胞及凋亡小体形成 ,DNA琼脂糖凝胶电泳结果显示清晰的 DNA梯状条带 ,原位末端标记检测出细胞凋亡率亦有时间、剂量依赖性 ,细胞内 [Ca2 +]随药物浓度的增加而升高 ,且具有统计学意义。结论 :天佛参口服液确有诱导 Hep- 2细胞凋亡的作用 ,其机制可能与胞内 [Ca2 +]变化有关。

天佛参口服液抗肿瘤机理的实验研究

目的 观察天佛参口服液对Ｈｅｐ－２细胞的影响以探讨其抗肿瘤的机理．方法 采用体外细胞培养实验方法。应用ＭＴＴ、透射电镜、ＤＮＡ琼脂糖凝胶电泳、ＴＵＮＥＬ等技术，检测药物对细胞的抑制率及凋亡率。结果 ＭＴＴ测得细胞抑制率随时间、剂量而增大：活细胞观察、透射电镜下见到凋亡细胞及凋亡小体形成，电泳结果显示清晰的ＤＮＡｌａｄｄｅｒ，ＴＵＮＥＬ法检测出细胞凋亡率具有时间、剂量依赖性，药物组与对照组有显著性差异，结论 天佛参口服液能诱导Ｈｅｐ－２细胞凋亡，细胞凋亡率随时间延长增加，且呈现剂量依赖性。