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目的：观察鼻咽癌细胞株CNE－1和CNE－2裸鼠移植瘤组织中肿瘤细胞凋亡的形态学特征，并探讨p53，bc1－2和bax在瘤细胞凋亡中所起的作用。方法：CNE－1和CNE－2鼻咽癌细胞株接种于裸鼠并在裸鼠体内连续传3代。在HE和TUNEL染色片中观察细胞株和各代移植瘤组织中癌细胞的凋亡；应用免疫组化法检测p53，bc1－2和bax基因的表达；抽提细胞株及各代移植瘤组织的DNA，以PCR－SSCP法检测p53基因第5～8外显子的改变。结果：在CNE－1和CNE－2移植瘤组织中有相当数量的瘤细胞发生凋亡，可见较大面积的“皱缩性坏死”区和众多的凋亡小体。PCR－SSCP显示p53基因第8外显子有改变，在细胞涂片和各代移植瘤组织中都有p53蛋白的积聚。3代移植瘤组织均有bax过表达，却无bc1－2表达。结论：CNE－1和CNE－2裸鼠移植瘤组织中肿瘤细胞死亡的主要途径是凋亡，表现为大量的“皱缩性坏死”和凋亡小体的形成；这种凋亡可能是非p53依赖性，由bax所介导的。
OBJECTIVE: To observe the morphological characteristics of tumor cell apoptosis in transplanted tumor tissues of nasopharyngeal carcinoma cell line CNE-1 and CNE-2 in nude mice, and to investigate the role of p53, bcl-2, and bax in tumor cell apoptosis. METHODS: CNE-1 and CNE-2 nasopharyngeal carcinoma cell lines were inoculated into nude mice and serially passaged in nude mice for 3 passages. Apoptosis of cancer cells in cell lines and in all generations of transplanted tumor tissues was observed in HE and TUNEL stained slides; the expression of p53, bcl-2, and bax genes was detected by immunohistochemistry; cell lines and all-generation transplanted tumor tissues were extracted. The DNA was analyzed by PCR-SSCP to detect changes in exon 5-8 of the p53 gene. RESULTS: A considerable number of neoplastic cells developed apoptosis in both CNE-1 and CNE-2 xenograft tumors, showing a large area of “crushed necrosis” and numerous apoptotic bodies. PCR-SSCP showed changes in exon 8 of the p53 gene and accumulation of p53 protein in both cell smears and in all generations of xenograft tumors. Three generations of xenograft tumors had bax overexpression but no bc1-2 expression. CONCLUSION: The main pathway of tumor cell death in CNE-1 and CNE-2 nude mice transplanted tumors is apoptosis, which is characterized by massive “shrinkage necrosis” and the formation of apoptotic bodies; this apoptosis may be non-p53 Dependence, mediated by bax.