Abstract:

Objective To investigate the inhibitory effect of low-dose lidamycin on the growth of P19 cells,in order to provide a reliable evidence for targeting cancer stem cells in cancer therapy.Methods  MTT assay was used to measure the dose curve and time curve after P19 cells were treated with lidamycin.Flow cytometry was employed to examine the  apoptosis and cell cycle of P19 cells treated with lidamycin and adriamycin.The  Oct4 expressions at mRNA and protein levels were tested by Real-time PCR,Western blotting and immunocytochemistry when the P19 cells were exposed to lidamycin and adriamycin.Results After exposure of the cells to lidamycin and adiramycin,the IC^₅₀ of lidamycin and adiramycin in P19 cells were 1×10^－11 mol/L and 0.5×10^－9 mol/L,respectively.Low doses of lidamycin range from 0.001 to 0.1 nmol/L^-1 were still effective to inhibit P19 embryonal carcinoma cell growth in 120 h. Flow cytometry indicated that  low-dose  lidamycin induced G1 stage arrest in P19 cells without apoptosis and  adiamycin induced G2 stage arrest.Real-time-PCR,Western blotting and immunochemistry showed that the expression levels of Oct4 were decreased in all test when the P19 cells were exposed to lidamycin,but not to adiamycin.Conclusion The inhibitory effect of low-dose lidamycin on P19 cell growth may be related to down-regulation of embryonic stem cell-like gene Oct4.

Key words: lidamycin;embryonic carcinoma P19 cells;transcription factor Oct4