Suppression of miR‐186 Attenuates Cellular Invasion, pAKT and β‐catenin in Metastatic Prostate Cancer Cell Models
Authors: Jones Dominique , Suman Suman Renee , Schmidt M. Lee , Hobbing Katharine R , Barve Shirish , Gobejishvili Leila , Klinge Carolyn , Rai Shesh , Clark Geoffrey , Brock Guy , Agarwal Rajesh , Kidd LaCreis Renee 
Published: June 2021

Background

MicroRNA (miR) dysregulation alters the expression of cancer related genes and contributes to disease states in many cancers. For example, ectopic miR‐186 expression leads to enhanced cell proliferation and migration in pancreatic cancer. However, the role of miR‐186 in prostate cancer (PCa) remains unclear. Previously, we observed significant upregulation of miR‐186‐5p in PCa patient serum (stage III/IV) and PCa cell lines relative to appropriate controls. Moreover, inhibition of miR‐186 reduced cell proliferation and anchorage‐independent growth of PC‐3 PCa cells. However, the impact of miR‐186 inhibition on cell invasion and its corresponding mechanism is unknown.

Hypothesis

We speculated miR‐186 inhibition would repress cellular invasion in metastatic PCa cell lines, presumably by up‐regulating tumor suppressor gene(s) involved in at least one hallmark of cancer.

Methods

Assessment of the impact of miR‐186 inhibition or overexpression on selected targets entailed microarray analysis, qRT‐PCR, and/or western blots. Candidate miR‐186 targets were selected using published reports on ‘miR‐186 and cancer’, availability of robust antibodies, and statistical filtering (false discovery ≥0.05 and ±1.2 fold change). Statistical evaluation used the modified t‐test, and ANOVA analysis.

Results

Mir‐186 inhibition in PC‐3 cells significantly repressed proliferation and colony formation by 34–64% in PC3 and/or MDA‐PCA‐2b cells. Following miR‐186 inhibition in PC‐3 cells and overexpression in RWPE1 cells, 1,040 identified mRNA targets were differentially expressed compared to scramble controls (p < 0.05). The candidate miR‐186 target gene list focused on 11 up‐regulated candidates. One of the up‐regulated genes, AKAP12, plays a role in cell death, cell migration, cell proliferation, colony formation, and cell invasion. AKAP12 also possessed three miR‐186 binding sites. Notably, AKAP12 was upregulated in PC‐3 and MDA‐PCa‐2b cells transfected with a miR‐186 inhibitor. Conversely, ectopic miR‐186‐5p expression in HEK 293T cells decreased AKAP12 expression by 30%. Both pAKT and β‐catenin were down‐regulated in miR‐186 inhibited PCa cells. Conversely, overexpressing miR‐186‐5p in normal prostate epithelial RWPE1 cells increased pAKT expression by 30%.

Conclusions

Our findings suggest miR‐186 plays an oncogenic role in PCa. The reduction in cell invasion in miR‐186 inhibited cell models corresponded with an up‐regulation of AKAP12, which in turn may reduce p‐AKT and β‐catenin. Repression of p‐AKT and β‐catenin favors a less invasive PCa phenotype. Future studies will further elucidate the mechanism by which miR‐186 inhibition suppresses cellular proliferation, migration, and invasion. Such efforts may lead to the identification of novel biomarkers to improve detection and clinical management strategies for aggressive PCa.

Support or Funding Information

National Cancer Institute Grant R25‐CA‐134283, Our Highest Potential Endowment in Cancer Research

This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.