红霉素对钾离子通道HERG高表达癌细胞的增殖抑制及其与化疗药物的协同作用

目的研究红霉素对钾离子通道HERG高表达癌细胞的增殖抑制及其与化疗药物的协同作用。方法采用Western印迹、四甲基偶氮唑蓝（MTT）法、流式细胞术、细胞黏附实验以及明胶酶谱法观察红霉素对肿瘤细胞的作用。结果HERG钾通道在人结肠癌HT-29细胞和小鼠结肠癌C26细胞中均有表达,和HERG钾通道高表达对照神经母细胞瘤SH-SY5Y相比,在HT-29细胞中表达量较高。红霉素对HT-29细胞和C26细胞的增殖具有不同程度的抑制作用,呈浓度依赖性。红霉素能将HT-29细胞阻滞于G2／M期,并引起明显的Sub G1峰。红霉素对HT-29细胞黏附于Ⅰ型胶原具有明显的抑制作用,存在明显的剂量-效应关系。红霉素能抑制肿瘤细胞释放明胶酶MMP-2。红霉素与长春新碱协同抑制小鼠C26细胞的增殖。长春新碱单用以及长春新碱与红霉素（50μmol／L）联用的IC50分别为62．65nmol／L和4．68nmol／L。红霉素与紫杉醇、羟基喜树碱联用亦显示协同作用。结论红霉素在能抑制钾离子通道HERG高表达癌细胞HT-29的增殖,并能诱导肿瘤细胞凋亡。红霉素与长春新碱等化疗药物显示协同作用。

Erythromycin inhibits the proliferation of HERG K+ channel highly expressing cancer cells and shows synergy with anticancer drugs

OBJECTIVE: To investigate the effects of erythromycin on the proliferation of the human ether-a-go-go related gene (HERG) K(+) channel highly expressing cancer cells and its synergy with antitumor chemotherapeutic agents. METHODS: Human fibrosarcoma cell of the line HT-1080, murine colon carcinoma cells of the line C26, human colon carcinoma cells of the line HT-29, human pulmonary epithelial cells of the line A549, and human neuroblastoma cells of the line SH-SY5Y were cultured. Western blotting was used to detect the protein expression of the HERG K(+) channel protein. Erythromycin, taxol, and vincristine were added into the culture fluid. to observe the proliferation of the cancer cells. Collagen I was used to coat 96-well plate, HT-29 cells were put into, and Erythromycin, taxol, and vincristine were added, MTT method was used to examine the cell adhesion. SDS-PAGE was used to detect the secretion of gelatinase. Flow cytometry was used to detect the cell cycle and apoptosis. The coefficient of drug interaction (CDI) was calculated. RESULTS: HERG K(+) channel expression was found in both HT-29 human colon carcinoma cells and C26 murine colon carcinoma cells. The expression level in HT-29 cells was higher than that in the positive control SHSY5Y neuroblastoma cells. Erythromycin suppressed the proliferation of HT-29 and C26 cells in a dose-dependent manner. There existed a remarkable G(2)/M arrest after the cells were exposed to erythromycin. Induction of apoptosis in HT-29 cells and inhibition of cell adhesion to collagen I were found. Erythromycin inhibited the secretion of MMP-2 from HT-29 cells in a dose-dependent manner. At sub-cytotoxic concentration, erythromycin potentiated the cytotoxicity of vincristine, taxol, and hydroxyl-camptothecin to C26 cells. The IC(50) values for vincristine and vincristine plus erythromycin (50 micromol/L) were 62.65 nmol/Land and 4.68 nmol/L respectively. CONCLUSION: Erythromycin inhibits the proliferation and induces the apoptosis of cancer cells with high HERG K(+) channel expression. Synergy is found in the combination of erythromycin with other anticancer agents.