EVODIAMINE INHIBITS THE PROLIFERATION OF K562 LEUKEMIA CELLS BY INHIBITING HDAC6 TO ACTIVATE THE MAPK SIGNALING PATHWAY

Donglu Zhao^*, Hang Song, Qi Xing, Keyu Liu, Yan Zhao

The Fourth Ward of Haematology, Haematology Research Center, Harbin First Hospital, Harbin 150010, PR China

Objective: We studied the possible mechanism by which evodiamine suppresses K562 leukemia cell proliferation by inhibiting HDAC6 to activate the MAPK signaling pathway. 

Methods: CCK-8 and chemical colorimetric methods and Western blot were used to detect the effect of evodiamine (Evo) on human K562 leukemia cell proliferation, histone deacetylase (HDAC) activity, and the mitogen-activated protein kinase (MAPK) pathway. 

Results: The CCK-8 results showed that Evo had a dose- and time-dependent inhibitory effect on K562 cell proliferation that was significantly stronger than the effect of the blank control (p<0.01). The IC50 of Evo acting on K562 cells was 12.14±0.96, 7.30±0.22, and 6.58±0.06 μmol/L at 24, 48, and 72 h, respectively (p<0.01). At 24, 48, and 72 h, rates of inhibition of K562 cell proliferation by 8 μmol/L Evo were 12.80±0.02%, 53.41±0.03%, and 69.03±0.02%, respectively (p<0.01). The chemical colorimetry test showed that after being induced by Evo for six hours, the absorbance of the 2, 4, and 8 μmol/L Evo groups were 0.11±0.02, 0.09±0.01, and 0.05±0.01, respectively compared to the blank control group (0.14±0.01; p<0.01). Western blot results showed that compared to the blank control group, the expression of HDAC1, HDAC2, HDAC3, and HDAC6 in the Evo groups was downregulated (p<0.01); the expression of HDAC2 was downregulated the most in the 2 μmol/L Evo group, that of HDAC1 and HDAC6 was downregulated the most in the 4 μmol/L Evo group, and that of HDAC3 was downregulated the most in the 8 μmol/L Evo group. The expression of p-ERK and JNK proteins in the Evo groups was significantly reduced, but that of p-38, p-p38 and p-JNK proteins was significantly increased (p<0.01). ERK protein expression was not significantly different in the Evo groups compared to that in the blank control group (p>0.05). 

Conclusion: Evo has broad antitumor activity that can effectively inhibit K562 cell proliferation in a time- and concentration-dependent manner. This may occur by inhibiting HDAC6 to activate the MAPK signaling pathway, leading to suppression of K562 cells.