HINT1对人黑素瘤A375细胞裸鼠皮下异种移植瘤模型肿瘤生长及凋亡的影响

Effects of HINT1 on the growth of and apoptosis in malignant melanoma in nude mouse models established by subcutaneous xenotransplantation of human melanoma A375 cells

目的 探讨组氨酸三聚体核苷结合蛋白1（HINT1）对人黑素瘤A375细胞裸鼠皮下异种移植瘤模型肿瘤生长及凋亡的影响.方法 三组裸鼠随机皮下接种HINT1-A375、neo-A375及未转染的A375细胞,观察各组移植瘤的生长情况,计算成瘤率.组织病理切片观察移植瘤组织形态学改变,并应用TUNEL法检测移植瘤组织中细胞凋亡情况.结果 三组裸鼠皮下异种移植瘤成瘤率均为100%.HINT1组移植瘤生长速度慢,接种后18 d移植瘤生长速度显著低于neo组及A375细胞组（P＜0.01）.HINT1组、neo组及A375细胞组肿瘤重量分别为（0.04±0.00）g、（0.23±0.00）g、（0.29±0.03）g;肿瘤体积分别为（0.06±0.04）cm^3、（0.34±0.15）cm^3、（0.43±0.19）cm^3.HINT1组肿瘤重量及体积均显著低于neo组及A375细胞组（P值均＜0.01）.组织病理结果显示,与neo组及A375细胞组相比,HINT1组肿瘤团块较小,细胞异形小,病理性核分裂象少见,瘤团内未见大片坏死灶.HINT1组中平均凋亡细胞百分比为12.87%±1.18%,显著高于neo组（3.22%±0.49%）及A375细胞组（3.00%±0.53%）（P值均＜0.01）.结论 高表达HINT1可显著抑制A375细胞裸鼠皮下异种移植瘤模型肿瘤的生长,促进其凋亡,提示HINT1基因可能是人黑素瘤的抑癌基因之一.

Objective To investigate the effects of HINT1 on the growth of and apoptosis in malignant melanoma in nude mouse models established by subcutaneous xenotransplantation of human melanoma A375 cells. Methods Three groups of nude mice were subcutaneously inoculated with A375 cells transfected with pcDNA 3.1/myc-His （-） A-HINT1 （HINT1-A375）, A375 cells transfected with pcDNA 3.1/myc-His （-） A empty vector （neo-A375）, and untransfected A375 cells, respectively. Then, the growth of transplanted tumors was observed and tumor formation rate was calculated. Thirty-three days after the inoculation, mice were killed and tumor tissue was obtained followed by the examination of tumor weight and volume. Histopathology was performed to observe the morphological features of tumor cells and in situ end labeling technique （TUNEL）was carried out to assess the apoptosis in transplanted tumor cells. Results The tumor formation rate was consistently 100% in the three groups. The transplanted tumor in HINT1 group grew more slowly than that in the other two groups, and significant difference was observed as early as day 18 （P 〈 0.01 ）. Lower tumor weight and volume were noted in the HINT1 group compared with the neo group and A375 cell group （0.04 ±0.00 g vs. 0.23 ± 0.00 g and 0.29 ± 0.03 g, 0.06 ± 0.04 cm^3 vs. 0.34 ± 0.15 cm^3 and 0.43 ± 0.19 cm^3 respectively, all P 〈 0.01 ）. Histopathology revealed smaller tumor nests, slight atypia of tumor cells with no obvious pathologic mitoses or necrosis in HINT1 group in comparison with the other two groups. Immunohistochemistry and TUNEL revealed that the percentage of apoptotic cells in HINT1 group was statistically higher than that in the neo group and A375 cell group （12.87% ± 1.18% vs. 3.22% ± 0.49% and 3.00% ± 0.53%, both P 〈0.01 ）. Conclusion High expression of HINT1 could inhibit the growth of and promote the apoptosis in malignant melanoma in nude mice subcutaneous xenotransplantation models, suggesting that HINT1 gene might be responsible for tumor suppression in human malignant melanoma.