Curcumin Promoted The Apoptosis Of Human Lung Adenocarcinoma Cells A549 And A549/DDP Through Down-regulating Mir-186*

Background and Objective:Curcumin is a natural compound, which is derived from the rthizom of Curcuma longa. In vitro and vivo studied, curcumin have shown its anti-inflammatory,antioxidant,anticancer activivties and so on. Mir-186*, a gene simultaneously highly expressed in human lung adenocarcinoma cells A549 and A549/DDP, which was found by microarray technology. Our studies mainly elucidated that curcumin was able to promote the apoptosis of A549 and A549/DDP cells, which might be through regulating the expression profile of mir-186*.Methods:1 A549 and A549/DDP cell lines were treated with curcumin and DMSO controls, respectively.2 An oligonucleotide microarray chip used to profile microRNA (miRNA) expressions in A549 and A549/DDP cell lines.3 The significantly differential expressed miRNAs were selected from A549 and A549/DDP cells, respectively.4 The significantly differential expressed miRNAs which was selected from microarray chip validated by quantitative real-time PCR.5 (1) The downstream target gene of the significantly differentially expressed miRNA was forcasted and selected though miRanda data base on line.(2) Potential mRNA targets of significantly expressed miRNA were selected and assayed by western-blot expriments in A549 cells;The remarkably expressed miRNA modulated the apoptosis assaying by flow cytometry expriments.(3) The significantly expressed miRNA in A549/DDP cells modulated the apoptosis assaying by flow cytometry expriments and the survival rate was measured by MTT method.Results:1. The microarray chip results demonstrated: compared with untreated control group, curcumin treatment down-regulated all the profile of mir-186* in A549 and A549/DDP cells.2. Quantitative real-time PCR confirmed the result of microarray above.3. (1) More than seven hundreds downstream target genes of mir-186* were forcasted though miRanda data base, the caspase10 correlation with the apoptosis was selected as the downstream target gene of mir-186* by classifying the gene function.(2) Compared control group, down-regulation of mir-186* expression by curcumin in A549 cells activated expression of its target gene caspase10 and elevated its apoptosis; Otherwise, after transfection mir-186* precursors and precursor controls in A549 cells, compared precursor controls, up-regulation of mir-186* expression by transfection its precursors suppressed caspase10 expression and restrained apoptosis.(3) Down-regulation of mir-186* expression by curcumin promoted the apoptosis, the survival rate of A549/DDP cells diminished; but up-regulation of mir-186* expression by transfection its precursors confined the apoptosis, the survival rate of A549/DDP cells raised, which were all detected by flow cytometry and MTT method.Conclusions:1. Caspase10 was one of the downstream target genes of mir-186*.2. Curcumin regulated the downstream target gene caspase10 though regulating the profile of the mir-186*.3. These observations show that a functionary mechanism of curcumin was by modulating mir-186* expression to promote the apoptosis of A549 and A549/DDP cells.