RESUMEN
This study aimed to analyze the possible association of miR-30a-5p, miR-30e-5p, and miR-34a-5p identified as potential candidate miRNAs in schizophrenia, with the COMT gene. Candidate miRNAs were obtained from the TargetScan database. The SH-SY5Y human neuroblastoma cell line was used as a cellular model for schizophrenia. miR-30a-5p, miR-30e-5p, and miR-34a-5p mimics were transfected into the SH-SY5Y cell line. Total RNA was isolated from transfected cells and RNA-IP samples and reverse transcripted for miRNA and mRNA analysis. RT-qPCR and western blot were performed to observe changes in expression levels of COMT. RNA-immunoprecipitation was performed to determine RNA-protein interactions after mimic transfection. In the study, it was observed that COMT gene expression levels decreased significantly after miR-30a-5p and miR-34a-5p expressions, whereas increased significantly as a result of miR-30e-5p transfection. RNA-IP data have shown that the amount of COMT pulled down by Ago2 was increased after miR-30a-5p and miR-34a-5p transfections. RNA-IP results revealed that miR-30a-5p and miR-34a-5p are direct targets for the COMT gene.
RESUMEN
MYC amplification and overexpression in breast cancer occur 16% and 22%, respectively, and MYC has a linchpin role in breast carcinogenesis. Emerging evidence has started to shed light on central role of MYC in breast cancer progression. On the contrary, tumor-derived exosomes and their cargo molecules are required for the modulation of the tumor environment and to promote carcinogenesis. Still, how MYC regulates tumor-derived exosomes is still a matter of investigation in the context of breast cancer. Here, we investigated for the first time how MYC affects the biological functions of normal breast cells cocultured with exosomes derived from MYC-expression manipulated breast cancer cells. Accordingly, exosomes were isolated from MCF-7 and MDA-MB-231 cells that MYC expression was manipulated through siRNAs or lentiviral vectors by using exosome isolation reagent. Then, normal breast epithelial MCF-10A cells were treated with breast cancer cell-derived exosomes. The cellular activity of MCF-10A was investigated by cell growth assay, wound healing assay, and transwell assay. Our results suggested that MCF-10A cells treated with exosomes derived from MYC-overexpressing breast cancer cells demonstrated higher proliferation and migration capability compared with nontreated cells. Likewise, MCF-10A cells treated with exosomes derived from MYC-silenced cancer cells did not show high proliferation and invasive capacity. Overall, MYC can drive the functions of exosomes secreted from breast cancer cells. This may allow exploring a new mechanism how tumor cells regulate cancer progression and modulate tumor environment. The present study clears the way for further researches as in vivo studies and multi-omics that clarify exosomal content in an MYC-dependent manner.
