[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.


CONCLUSIONS
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.
Chen
Shu-zhen
SZ
Institute of Medicinal Biotechnology, Chinese Academy of Medical Science & Peking Union Medical College, Beijing, 100050, China.
Zhang
Sheng-hua
SH
Gong
Jian-hua
JH
Zhen
Yong-su
YS
D000818:Animals; D000972:Antineoplastic Agents, Phytogenic / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects; D015153:Blotting, Western; D002448:Cell Adhesion / Q000187:drug effects; D002453:Cell Cycle / Q000187:drug effects; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D004357:Drug Synergism; D000072237:ERG1 Potassium Channel; D004917:Erythromycin / Q000494:pharmacology*; D051638:Ether-A-Go-Go Potassium Channels / Q000378:metabolism*; D005434:Flow Cytometry; D019073:HT29 Cells; D006801:Humans; D009369:Neoplasms / Q000378:metabolism / Q000473:pathology; D014750:Vincristine / Q000494:pharmacology*
D000972:Antineoplastic Agents, Phytogenic; D000072237:ERG1 Potassium Channel; D051638:Ether-A-Go-Go Potassium Channels; C000606913:KCNH2 protein, human; D014750:Vincristine; D004917:Erythromycin