Zhu Li-li, Hu Wan-le, Zhang Lin-jun, Yu Zhi-gao, Huang Chong-jie, Jiang Ming-zhe, Teng Ming-xing, Liu Jian-lu, Liu Chang-bao
Anorectal Department, the Second Affiliated Hospital of Wenzhou Medical College, Wenzhou 325027, China.
Zhonghua Zhong Liu Za Zhi. 2013 Apr;35(4):256-61. doi: 10.3760/cma.j.issn.0253-3766.2013.04.004.
To evaluate the effect of capsaicin on nude mice xenografted with colorectal carcinoma cells, and to explore its mechanism of action.
A nude mouse model of colorectal cancer was established by subcutaneous inoculation of human colorectal carcinoma HT-29 cells. Terminal deoxynucleotidyl transferase-mediated nicked labeling assay (TUNEL) was undertaken to detect the cell proliferation and apoptosis in the xenograft tissue in nude mice. Immunohistochemical (IHC) staining and Western blot were used to detect the expression of HSP27, Cyt-C and active caspase-3.
The tumor growth of the groups C10 and C20 was significantly slower than that of the group NS. The integrated optical density (IOD) of both the group C5 (2532.14 ± 578.11) and group C10 (6364.03 ± 1137.98) was significantly higher than that of the group NS (760.12 ± 238.05), (P < 0.05). The integrated optical density (IOD) of the group C20 was (15743.96 ± 1855.95), significantly higher than that of the groups C10, C5 and NS (all were P < 0.01). Immunohistochemistry showed that the cytoplasmic expression of HSP27 was strongly positive in the group NS, and significantly reduced with the increasing dose of capsaicin in the treated groups. The expression of active caspase-3 and Cyt-C in the group NS was weakly positive, and was significantly increased with the increasing dose of capsaicin in the groups C5 and C10 (P < 0.05), and the expression of active caspase-3 and Cyt-C of the group C20 was significantly higher than that of the groups C5, C10 and NS (P < 0.01). Western blot analysis showed that both the expressions of HSP27 of the group C5 (0.73 ± 0.05) and the group C10 (0.41 ± 0.03) were significantly lower than that of the group NS (P < 0.05). The expression of HSP27 of the group C20 (0.22 ± 0.06) was significantly lower than that of the groups C5, C10 and NS (P < 0.01). The expressions of active-caspase-3 and Cyt-C in the group C5 were (2.57 ± 0.34) and (2.03 ± 0.38), significantly higher than those of the group NS (P < 0.05). The expressions of active-caspase-3 and Cyt-C in the group C10 were (4.23 ± 0.45) and (3.13 ± 0.44), also significantly higher than those of the group NS (P < 0.05). The expressions of active-caspase-3 and Cyt-C in the group C20 were (5.78 ± 0.48) and (4.92 ± 0.52), significantly higher than those of the group C5, C10 and NS (P < 0.01). TUNEL analysis showed that there was a significant difference of cell apoptosis in comparison of each two groups. The higher dose of capsaicin was used, the more apoptosis was observed.
Capsaicin can significantly inhibit the tumor growth and induce cell apoptosis in the colorectal carcinoma xenograft in nude mice. Its mechanism of action is possibly related with the down-regulation of HSP27 expression and up-regulation of expression of active caspase-3 and Cyt-C in the colorectal carcinoma xenograft in nude mice.
评估辣椒素对接种大肠癌细胞的裸鼠的作用，并探讨其作用机制。
通过皮下接种人结肠癌细胞HT-29建立裸鼠结肠癌模型。采用末端脱氧核苷酸转移酶介导的缺口末端标记法（TUNEL）检测裸鼠移植瘤组织中的细胞增殖和凋亡情况。采用免疫组织化学（IHC）染色和蛋白质印迹法检测热休克蛋白27（HSP27）、细胞色素C（Cyt-C）和活化型半胱天冬酶-3的表达。
C10组和C20组的肿瘤生长明显慢于NS组。C5组（2532.14±578.11）和C10组（6364.03±1137.98）的积分光密度（IOD）均显著高于NS组（760.12±238.05），（P<0.05）。C20组的积分光密度（IOD）为（15743.96±1855.95），显著高于C10组、C5组和NS组（均为P<0.01）。免疫组织化学显示，NS组HSP27的细胞质表达呈强阳性，在治疗组中随着辣椒素剂量的增加而显著降低。NS组活化型半胱天冬酶-3和Cyt-C的表达呈弱阳性，在C5组和C10组中随着辣椒素剂量的增加而显著增加（P<0.05），C20组活化型半胱天冬酶-3和Cyt-C的表达显著高于C5组、C10组和NS组（P<0.01）。蛋白质印迹分析显示，C5组（0.73±0.05）和C10组（0.41±0.03）HSP27的表达均显著低于NS组（P<0.05）。C20组（0.22±0.06）HSP27的表达显著低于C5组、C10组和NS组（P<0.01）。C5组活化型半胱天冬酶-3和Cyt-C的表达分别为（2.57±0.34）和（2.03±0.38），显著高于NS组（P<0.05）。C10组活化型半胱天冬酶-3和Cyt-C的表达分别为（4.23±0.45）和（3.13±0.44），也显著高于NS组（P<0.05）。C20组活化型半胱天冬酶-3和Cyt-C的表达分别为（5.78±0.48）和（4.92±0.52），显著高于C5组、C10组和NS组（P<0.01）。TUNEL分析显示，各组之间细胞凋亡存在显著差异。辣椒素剂量越高，观察到的凋亡越多。
辣椒素可显著抑制裸鼠结肠癌移植瘤的生长并诱导细胞凋亡。其作用机制可能与下调裸鼠结肠癌移植瘤中HSP27的表达以及上调活化型半胱天冬酶-3和Cyt-C的表达有关。
