Mechanically, mitogen‑activated protein kinase kinase kinase 3 (MAP3K3) was identified as a direct target of miR‑505 by binding to its 3'untranslated region and demonstrated to mediate the tumor suppressor roles of miR‑505 in NSCLC cells.
Compelling evidence has suggested the relevance of miRNAs in resistance to chemotherapeutic agents in HCC. miR-505 was reported to be downregulated and function as a tumor suppressor in HCC cells by binding to high-mobility group box 1 (HMGB1).
RT-PCR validation demonstrated three downregulated miRNAs in F-CAFs compared with NFs (miR-145-3p, miR-299-3p, and miR-505-3p), two in F-CAFs compared with In-CAFs (miR-410-3p and miR-485-5p), but no differentially expressed miRNAs between In-CAFs and NFs.
Many miRNAs found in luminal tumors are expressed during normal mammary development. miR-135b, miR-505 and miR-155 are expressed in both basal human and mouse mammary tumors and many basal-associated miRNAs have not been previously characterized. miRNAs associated with the initiating oncogenic event driving tumorigenesis were also identified. miR-10b, -148a, -150, -199a and -486 were only expressed in normal mammary epithelium and not tumors, suggesting that they may have tumor suppressor activities.