Cytotoxic effects of a sesquiterpene β-elemene on THP-1 leukemia cells is mediated via crosstalk between beclin-1 mediated autophagy and caspase-dependent apoptosis

[Display omitted] •β- elemene was tested for its cytotoxic effect against THP-1 cells via MTT assay.•Expression of mRNAs of certain autophagy and apoptotic genes were evaluated by quantitative PCR.•There is a crosstalk between autophagy and apoptosis as determined by mRNA expressions. β- elemene extracted from Curcuma zedoaria rhizome (commonly known as white turmeric) is an effective anticancer agent. There are limited reports on the use of this agent against THP-1 cells employing a mechanistic study. Therefore, as a foremost aim of the present study, the cytotoxic effect of elemene and its mechanism will be elucidated. For this aim, the method adopted was to treat THP-1 cells in a dose- and time- dependent manner with elemene and the cytotoxicity to be evaluated. The mRNA expressions of a set of autophagy and apoptosis related genes will be analyzed by quantitative PCR. The findings indicate that the IC50 values for 24, 48, 72 and 96 h of treated THP-1 cells were 64.71, 42.19, 25.29 and 20.21 μg/mL respectively. The expressions of autophagy related genes such as Beclin-1, LC3II, ATG-5 and XBP-1 were upregulated. The expressions of anti-apoptotic Bcl2 was upregulated, whereas, the expression of pro-apoptotic Bax was downregulated. Interestingly, the expressions of Caspase-3 and Caspase-8 were upregulated. To summarize, autophagy might have occurred in endoplasmic reticulum and there might be a crosstalk with apoptosis which could be the rationale behind the cytotoxic effects of elemene on THP-1 cells. Therefore, β- elemene could be a potential therapeutic agent for leukemia.