Cortex mori extract induces cancer cell apoptosis through inhibition of microtubule assembly.
The water extract from the root bark of Cortex Mori (CM, Morus alba L.: Sangbaikpi), a mulberry tree, has been known in Chinese traditional medicine to have antiphlogistic, diuretic, and expectorant properties. In this study, the cytotoxicity of CM against tumor cells and its mechanism was examined. CM exhibited cytotoxic activity on K-562, B380 human leukemia cells and B16 mouse melanoma cells at concentrations of > 1 mg/ml. A DNA fragmentation, PARP cleavage, and nuclear condensation assay showed that those cells exposed to CM underwent apoptosis. The water extract of Scutellarie Radix (SR) was used as a negative control and showed no cytotoxicity in those cells. The flow cytometric profiles of the CM-treated cells were also indicative of apoptosis. However, they did not appear to exert the G1 arrest, which is observed in other tubulin inhibitor agents such as vincristine, taxol. The protein-binding test using Biacore and a microtubule assembly-disassembly assay provided evidence showing that CM bound to the tubulins resulting in a marked inhibition of the assembly, but not the disassembly of microtubules. The possible nonspecific effect of the CM extract could be excluded due to the results using SR, which did not affect the assembly process. Overall, the water extract of CM induces apoptosis of tumor cells by inhibiting microtubule assembly.
Nam
Sang-Yun
SY
Department of Microbiology, School of Natural Science, Jeonju University, Korea.
Yi
Ho-Keun
HK
Lee
Jung Chang
JC
Kim
Jae Cheol
JC
Song
Chang Ho
CH
Park
Jin Woo
JW
Lee
Dae Yeol
DY
Kim
Jung Soo
JS
Hwang
Pyoung Han
PH
D000972:Antineoplastic Agents, Phytogenic / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D016193:G1 Phase / Q000187:drug effects; D006801:Humans; D008870:Microtubules / Q000187:drug effects*; D010936:Plant Extracts / Q000494:pharmacology*; D010946:Plants, Medicinal; D014404:Tubulin / Q000378:metabolism; D014407:Tumor Cells, Cultured
D000972:Antineoplastic Agents, Phytogenic; D010936:Plant Extracts; D014404:Tubulin