ABSTRACT
Circular RNA (circRNA) is a novel RNA with circular structures. It is conserved in various species, and characterized by high stability, high expression levels and tissue specificity. Meanwhile, it could serve as microRNA (miRNA) sponges, bind to RNA-binding proteins, or regulate transcription and protein translation. With the development of high-throughput sequencing and bioinformatics, circRNA was reported to participate in the pathogenesis of cancer. N6-methyladenosine (m6A) modification is the most common type of RNA modification in eukaryote RNA, which is a dynamic and reversible process regulated by m6A methyltransferase, m6A demethylase and m6A-binding proteins. M6A modification isinvolved in the regulation of RNA nuclear export, splicing, stability, translation and degradation, thus playing a key role in the occurrence and development of multiple human diseases, such as cancers, cardiovascular diseases. Recently, some researches demonstrated that m6A modification of circRNA was essential in the occurrence and development of malignant tumors, such as cervical cancer, colorectal carcinoma, hepatocellular carcinoma, non-small cell lung cancer, poorly differentiated adenocarcinoma of the stomach. In the current manuscript, we summarized the mechanism of m6A RNA modification, the roles of m6A modification in regulation of circRNA, and the effects of circRNA m6A modification on tumor. The potential clinical application value of m6A-modified circRNA was further discussed, as to provide some new ideas and ways for early diagnosis, clinical treatment and prognosis of tumors.
ABSTRACT
Objective To investigate the mechanism of klotho reversing the resistance of breast cancer to paclitaxel in MCF-7/PTX cells.Methods The Klotho expression in MCF-7 and MCF-7/PTX cells was detected by Western blot.The effects of Klotho on paclitaxel resistance in MCF-7/PTX cells was measured by MTT assay.The effects of Klotho and 3-methyladenine (3-MA) on proliferation and expression of Beclin1 in MCF-7/PTX cells were detected by MTT and Western blot assay,respectively.Results The expression of Klotho in MCF-7/PTX cells was decreased compared with MCF-7 cells.Klotho could sensitize MCF-7/PTX cells to paclitaxel.The expression of Beclin1 in MCF-7/PTX cells was higher than that in MCF-7 cells.Klotho and 3-MA could decrease the expression of Beclin1 in MCF-7/PTX cells,and the effects of Klotho on paclitaxel resistance in MCF-7/PTX cells was similar to that of 3-MA.Conclusion Paclitaxel resistance in breast cancer cells is related to expression of the Klotho which can reverse the resistance of breast cancer to paclitaxel by inhibiting autophagy.