Dual-strand tumor suppressor miR-193b-3p and -5p inhibit malignant phenotypes of lung cancer by suppressing their common targets

Abstract

Emerging studies suggest that microRNAs (miRNAs) play multiple roles in cancer malignancy, including proliferation and acquisition of metastatic potential. Differentially expressed miRNAs responsible for the malignancy of lung cancer were searched by miRNA microarray using a previously established brain metastatic lung cancer model. Twenty-five miRNAs were down-regulated in brain metastatic lung cancer cells. Among those, miR-193b-3p and -5p were chosen for further studies. Their function in metastatic potential and proliferation was examined using Transwell invasion, wound healing, and colony forming assays. The underlying mechanism of tumor-suppressor miR-193b-3p and -5p was explored using reverse transcriptase quantitative polymerase chain reaction (RT-qPCR), Western blot, Argonaute 2-RNA immunoprecipitation (Ago2-RIP), and reporter assays. Both strands of miR-193b were down-regulated in brain metastatic lung cancer cells and in tissues from lung cancer patients. Overexpression of miR-193b-3p and -5p inhibited invasive and migratory activities and diminished clonogenic ability. Conversely, inhibition of miR-193b-3p or -5p increased the metastatic potential and colony forming ability. Cyclin D1 (CCND1), Ajuba LIM Protein (AJUBA), and heart development protein with EGF like domains 1 (HEG1) were identified as common target genes of miR-193b-3p and -5p. A reporter assay and an Ago2-RIP experiment showed that both miRNAs directly bind to the 3′ untranslated region (3′UTR) of the target mRNA. Knockdown of target gene reduced the proliferative and metastatic potential of primary and metastatic lung cancer cells. Our results demonstrate miR-193b is a dual-strand tumor suppressor and a novel therapeutic target for lung cancer.

AJUBA: A regulator of epidermal homeostasis and cancer

“…activity of lung cancer cell lines. 110 Lastly, cervical cancer patients displaying high AJUBA expression positively correlated with resistance to cisplatin treatment via YAP/TAZ upregulation. 111 AJUBA can also functions as a tumor suppressor in some cancers inhibiting cell growth and migration by modulating several cellular components and proteins.…”

“…Similar promotion of migration is seen in lung cancer. Precisely, miR‐193b‐3p and −5p inhibition led to increased metastatic potential and both miRNA’s decreased AJUBA expression resulting in a decrease in migration, proliferation and colony‐forming activity of lung cancer cell lines 110 . Lastly, cervical cancer patients displaying high AJUBA expression positively correlated with resistance to cisplatin treatment via YAP/TAZ upregulation 111 …”

microRNA strand selection: Unwinding the rules

“…miR‐144* (5p) directly targets ATF2, and it is possible that increased ATF2 levels upon reduced miR‐144* (5p) activity contributes to progression of NSCLC (Song et al, 2018). In another example, both miR‐193b (3p) and miR‐193b* (5p) are down regulated in lung cancer and restoring the levels of either strand suppresses malignant phenotypes including metastatic potential and cell proliferation (Choi et al, 2019), (Table 1). Both strands appear to target Cyclin‐D (CCND1), Ajuba LIM protein (AJUBA) and heart developmental protein with EGF like domains (HEG1) and knocking down those targets phenocopies restored miR‐193b levels (Choi et al, 2019).…”

Hsa_circ_0128846 promotes tumorigenesis of colorectal cancer by sponging hsa‐miR‐1184 and releasing AJUBA and inactivating Hippo/YAP signalling

“…Also, it has been reported that AJUBA could be regulated by miRNAs. 35,36 Nonetheless, how AJUBA being regulated by miRNAs in CRC has not been studied.…”