抗菌肽LL-37 与膀胱尿路上皮癌关系的初步探讨

Relationship between antibacterial peptide LL-37 and bladder urothelial carcinoma

摘要:

目的 检测抗菌肽LL-37 在膀胱尿路上皮癌中的表达，同时体外研究LL-37 对膀胱肿瘤细胞株T24、EJ 的作用。方法 ELISA 检测30 例膀胱尿路上皮癌患者和30 例健康体检者新鲜晨尿中LL-37 的表达，同时检测T24、EJ 细胞和尿路上皮SV-HUC-1 细胞经不同浓度LPS 刺激后细胞培养液上清中LL-37水平。免疫组织化学和逆转录聚合酶链反应（RT-PCR）分别检测30 例膀胱癌患者的肿瘤组织标本、肿瘤基底及周围组织标本中LL-37 的表达。在体外将不同浓度的LL-37 作用于T24、EJ 和SV-HUC-1 细胞，MTT 检测细胞的增殖。结果 健康体检者和膀胱癌患者尿液中LL-37 的水平分别为（2.02±0.06）和（24.32±0.02）ng/ml，差异有统计学意义（P <0.05）。免疫组织化学结果显示，LL-37 在癌组织中表达阴性，而在癌组织周围的炎症细胞、血管壁及平滑肌内却呈阳性表达。RT-PCR 结果表明，癌周围组织中LL-37的表达水平比癌组织高约30 倍。T24、EJ 和SV-HUC-1 细胞经LPS 刺激后培养液上清中LL-37 浓度均升高。在体外，LL-37 呈剂量依赖性地抑制T24、EJ 细胞的增殖，而其对SV-HUC-1 细胞的抑制需更高的浓度。结论 LL-37 与膀胱癌的发生可能有着一定的关联，体外高浓度的LL-37 可抑制膀胱癌T24、EJ 细胞的生长。

Abstract:

Objective To detect the expression of antimicrobial peptide LL-37 in bladder urothelial carcinoma, and research the effect of LL-37 on bladder cancer cell lines T24 and EJ in vitro. Methods ELISA was used to detect the level of LL-37 expression in the fresh morning urine of 30 patients with bladder urothelial carcinoma and 30 healthy people, and LL-37 levels in cell culture supernatant secreted by the bladder cancer T24 and EJ cells and urothelial SV-HUC-1 cells after treatment with different concentrations of LPS. Immunohistochemistry and RT-PCR were used to detect LL-37 expression levels of tumor tissues, tumor base and pericancerous tissues in 30 resected bladder cancer specimens. MTT was utilized to detect the proliferation of the T24, EJ and SV-HUC-1 cells treated with different concentrations of LL-37 in vitro. Results The levels of LL-37 in the urine of the healthy and bladder cancer patients were (2.02 ± 0.06) ng/ml and (24.32 ± 0.02) ng/ml respectively, the LL-37 level of the latter was significantly higher (P < 0.05). Immunohistochemistry displayed negative LL-37 expression in the cancer tissues,and positive expression in the inflammatory cells, vascular wall and smooth muscle cells surrounding the carcinoma tissues. RT-PCR results suggested that the LL-37 level in the pericancerous tissues was about 30 times higher than that in the cancerous tissues. The concentrations of LL-37 were elevated in the supernatant of T24, EJ and SV-HUC-1 cells after stimulation by LPS. In vitro, LL-37 inhibited the proliferation of T24 and EJ cells in a dose-dependent manner, however its inhibition to SV-HUC-1 cells needed higher concentrations. Conclusions There may be a relevance between LL-37 and the occurrence of bladder cancer, and high concentration of LL-37 can inhibit the growth of EJ and T24 cells in vitro.