Harmine Hydrochloride Induced G2/M Phase Cell Cycle Arrest, Autophagy and Apoptosis in Human Leukemia K562 Cells through Modulation of the MAPK Pathway

Background Previous studies have indicated that harmine hydrochloride (HAR-HC) has anti-tumor characteristics. However, its potential impact on human leukemia cells is unknown. In this study, we explored the potential mechanism of HAR-HC effects on human leukemia cells in vitro. Methods MTT assay was used to detect cell viability; A flow cytometer was used to analyze the cell cycle; Anexinn V-FITC/PI was used to detect cell apoptosis; Western blotting assay was used to analyze the expression of related proteins. Results The result of flow cytometry suggested G2/M phage arrest in K562 cells induced by HAR-HC. The expression levels of Cyclin E2, Cyclin D1, Bcl-2, Bcl-xL, Mcl-1, pro-caspase-3, and PARP decreased and the expression levels of Cyclin A2, Cyclin B1, p21, Myt-1, p-cdc2 (Tyr15), cleaved -caspase-3 and cleaved-PARP increased. Moreover, the expression of p-JNK and p-ERK1/2 increased and autophagy was induced in the HAR-HC treatment group. Additionally, HAR-HC facilitated autophagy by activating the ERK1/2 pathway. Conclusion HAR-HC induced G2/M phase cell cycle arrest, autophagy and apoptosis by activating the JNK, and ERK1/2 pathways in the human leukemia K562 cells.

Albendazole-Induced SIRT3 Upregulation Protects Human Leukemia K562 Cells from the Cytotoxicity of MCL1 Suppression

Previous studies have shown that MCL1 stabilization confers cancer cells resistance to microtubule targeting agents (MTAs) and functionally extends the lifespan of MTA-triggered mitotically arrested cells. Albendazole (ABZ), a benzimidazole anthelmintic, shows microtubule-destabilizing activity and has been repositioned for cancer therapies. To clarify the role of MCL1 in ABZ-induced apoptosis, we investigated the cytotoxicity of ABZ on human leukemia K562 cells. Treatment with ABZ for 24 h did not appreciably induce apoptosis or mitochondrial depolarization in K562 cells, though it caused the mitotic arrest of K562 cells. ABZ-evoked p38 MAPK activation concurrently suppressed Sp1-mediated MCL1 expression and increased SIRT3 mRNA stability and protein expression. ABZ and A-1210477 (an MCL1 inhibitor) enhanced the cytotoxicity of ABT-263 (a BCL2/BCL2L1 inhibitor) to their effect on MCL1 suppression. Unlike ABZ, A-1210477 did not affect SIRT3 expression and reduced the survival of K562 cells. Overexpression of SIRT3 attenuated the A-1210477 cytotoxicity on K562 cells. ABZ treatment elicited marked apoptosis and ΔΨm loss in ABT-263-resistant K562 (K562/R) cells, but did not alter SIRT3 expression. Ectopic expression of SIRT3 alleviated the cytotoxicity of ABZ on K562/R cells. Collectively, our data demonstrate that ABZ-induced SIRT3 upregulation delays the apoptosis-inducing effect of MCL1 suppression on apoptosis induction in K562 cells.

Preparation of Artesunate mPEG-PLGA Nanoparticles and Its Application to K562 Apoptosis of cells

The preparation process of artesunate-loaded polyethylene glycol monomethyl ether-polylactic acid-glycolic acid affinity block copolymer (mPEG-PLGA) nanoparticles and its growth inhibition on human leukemia K562 cells were investigated. METHODS: Artesunate mPEG-PLGA nanoparticles (Art-Nps) were prepared by modified self-emulsification method. The morphology of nanoparticles was characterized by scanning electron microscopy. The particle size distribution and zeta potential were measured by laser scattering particle size analyzer. The drug loading, encapsulation efficiency and in vitro release of Art-Nps were determined by chromatography. The proliferation and apoptosis of human leukemia K562 cells were observed by MTT assay and Hoechst staining. RESULTS: Art-Nps is a spherical solid particle with smooth surface, average particle size (156.70+/-1.01) nm, zeta potential of -(26.23+/-1.86) mV, average drug loading (14.51+/-0.20)%, average package. The sealing rate was (86.51+/-0.50)%, and the in vitro release law accorded with the Higuchi equation: Q=4.11t 1/2+27.05, R2=0.98. MTT assay showed that Art-Nps inhibited the proliferation of K562 cells in a time-dose-dependent manner, and the inhibition rate exceeded the artesunate-treated group after 72h, and sustained release. The number of cells was observed after cultured with different concentrations of Art-Nps for 48h. Significantly reduced, cell size is different, irregular shape, high magnification can be seen in the nucleus pyknosis, agglutination, and apoptotic bodies, and increased apoptotic bodies with increasing concentration.