MicroRNA-520a-5p displays a therapeutic effect upon chronic myelogenous leukemia cells by targeting STAT3 and enhances the anticarcinogenic role of capsaicin
Aberrant expression profiles of microRNAs (miRNAs) have been previously demonstrated for having essential roles in a wide range of cancer types including leukemia. Antiproliferative or proapoptotic effects of capsaicin have been reported in several cancers. We aimed to study miRNAs involved in the Janus kinase/signal transducers and activators of transcription (JAK/STAT) pathway in chronic myeloid leukemia cell model and the effects of the capsaicin treatment on cell proliferation and miRNA regulation. miR-520a-5p expression was extremely downregulated in capsaicin-treated cells. Repressing the level of miR-520a-5p by transient transfection with specific miRNA inhibitor oligonucleotides resulted in induced inhibition of proliferation in leukemic cells. According to bioinformatics analysis, STAT3 messenger RNA was predicted as a putative miR-520a-5p target; which was confirmed by quantitative reverse transcriptase–polymerase chain reaction (qRT-PCR) and Western blot analysis. Cell proliferation inhibition was enhanced upon knockdown of STAT3 by RNA interference applications, but when miR-520a-5p inhibitor was additionally transfected onto STAT3 silenced cells, cell viability was dramatically decreased in leukemia cells. Finally, we observed the effects of capsaicin following miR-520a-5p inhibitor transfection upon cell proliferation, apoptosis, and STAT3 expression levels. We determined that, downregulation of miR-520a-5p affected the proliferation inhibition enhanced by capsaicin and reduced STAT3 mRNA and protein expression levels and increased apoptotic cell number. In summary, miR-520a-5p displays a therapeutic effect by targeting STAT3 and impacting the anticancer effects of capsaicin; whereas capsaicin, potentially through the miR-520a-5p/STAT3 interaction, induces apoptosis and inhibits K562 leukemic cell proliferation with need of further investigation.
KeywordsChronic myeloid leukemia miRNA siRNA Capsaicin qRT-PCR Cell proliferation Apoptosis
We gratefully thank Prof. Dr. Cumhur Gündüz from Ege University Medical School, Medical Biology Department, for his assistance in apoptosis assay by directing us in flow cytometer analyses results.
- 7.Soverini S, Hochhaus A, Nicolini FE, Gruber F, Lange T, Saglio G, et al. BCR-ABL kinase domain mutation analysis in chronic myeloid leukemia patients treated with tyrosine kinase inhibitors: recommendations from an expert panel on behalf of European LeukemiaNet. Blood. 2011;118(5):1208–15.CrossRefPubMedGoogle Scholar
- 10.Ho CS, Yap SH, Phuah NH, In LL, Hasima N. MicroRNAs associated with tumour migration, invasion and angiogenic properties in A549 and SK-Lu1 human lung adenocarcinoma cells. Lung Cancer. 2013.Google Scholar
- 25.Kaymaz BT, Selvi N, Gunduz C, Aktan C, Dalmizrak A, Saydam G, et al. Repression of STAT3, STAT5A, and STAT5B expressions in chronic myelogenous leukemia cell line K-562 with unmodified or chemically modified siRNAs and induction of apoptosis. Ann Hematol. 2013;92(2):151–62.CrossRefPubMedGoogle Scholar
- 41.Choi SE, Kim TH, Yi SA, Hwang YC, Hwang WS, Choe SJ, et al. Capsaicin attenuates palmitate-induced expression of macrophage inflammatory protein 1 and interleukin 8 by increasing palmitate oxidation and reducing c-Jun activation in THP-1 (human acute monocytic leukemia cell) cells. Nutr Res. 2011;31(6):468–78.CrossRefPubMedGoogle Scholar