Luteolin-regulated MicroRNA-301-3p Targets Caspase-8 and Modulates TRAIL Sensitivity in PANC-1 Cells.

BACKGROUND/AIM: MicroRNAs (miRNAs) play regulatory roles in pancreatic ductal adenocarcinoma (PDAC). However, it is still required to identify the function of miRNA-301-3p in pancreatic cancer cells. MATERIALS AND METHODS: Effects of luteolin on cell growth, TRAIL cytotoxicity, and miR-301-3p levels were evaluated. The role of miRNA-301-3p in regulating cell proliferation, target gene expression, and TRAIL cytotoxicity were studied. RESULTS: The levels of miR-301-3p were down-regulated in PANC-1 cells exposed to luteolin, which inhibits the growth of PANC-1 cells and sensitizes cells to TRAIL. The knockdown of miR-301-3p attenuates cell proliferation and enhances TRAIL cytotoxicity. In addition, caspase-8 was directly targeted by miR-301-3p. CONCLUSION: Our findings unveil a critical biological function of miR-301-3p in regulating cell proliferation and elevating an antiproliferative effect of TRAIL on cancer cells. Our observation of miR-301-3p/caspase-8 relationship can also serve to clarify the role of miR-301-3p in other cancer types and related diseases.

An In Vitro Protocol for Evaluating MicroRNA Levels, Functions, and Associated Target Genes in Tumor Cells.

MicroRNAs (miRNAs) are small regulatory RNAs which are recognized to modulate numerous intracellular signaling pathways in several diseases including cancers. These small regulatory RNAs mainly interact with the 3' untranslated regions (3' UTR) of their target messenger RNAs (mRNAs) ultimately resulting in the inhibition of decoding processes of mRNAs and the augmentation of target mRNA degradations. Based on the expression levels and intracellular functions, miRNAs are able to serve as regulatory factors of oncogenic and tumor-suppressive mRNAs. Identification of bona fide target genes of a miRNA among hundreds or even thousands of computationally predicted targets is a crucial step to discern the roles and basic molecular mechanisms of a miRNA of interest. Various miRNA target prediction programs are available to search possible miRNA-mRNA interactions. However, the most challenging question is how to validate direct target genes of a miRNA of interest. This protocol describes a reproducible strategy of key methods on how to identify miRNA targets related to the function of a miRNA. This protocol presents a practical guide on step-by-step procedures to uncover miRNA levels, functions, and related target mRNAs using the probe-based real-time polymerase chain reaction (PCR), sulforhodamine B (SRB) assay following a miRNA mimic transfection, dose-response curve generation, and luciferase assay along with the cloning of 3' UTR of a gene, which is necessary for proper understanding of the roles of individual miRNAs.

MicroRNA-Based Combinatorial Cancer Therapy: Effects of MicroRNAs on the Efficacy of Anti-Cancer Therapies.

The susceptibility of cancer cells to different types of treatments can be restricted by intrinsic and acquired therapeutic resistance, leading to the failure of cancer regression and remission. To overcome this problem, a combination therapy has been proposed as a fundamental strategy to improve therapeutic responses; however, resistance is still unavoidable. MicroRNA (miRNAs) are associated with cancer therapeutic resistance. The modulation of dysregulated miRNA levels through miRNA-based therapy comprising a replacement or inhibition approach has been proposed to sensitize cancer cells to other anti-cancer therapies. The combination of miRNA-based therapy with other anti-cancer therapies (miRNA-based combinatorial cancer therapy) is attractive, due to the ability of miRNAs to target multiple genes associated with the signaling pathways controlling therapeutic resistance. In this article, we present an overview of recent findings on the role of therapeutic resistance-related miRNAs in different types of cancer. We review the feasibility of utilizing dysregulated miRNAs in cancer cells and extracellular vesicles as potential candidates for miRNA-based combinatorial cancer therapy. We also discuss innate properties of miRNAs that need to be considered for more effective combinatorial cancer therapy.

MicroRNA-107 Targets IKBKG and Sensitizes A549 Cells to Parthenolide.

BACKGROUND/AIM: Patients with advanced non-small cell lung cancer (NSCLC) frequently face a dismal prognosis because of lack of curative therapies. We, therefore, conducted a preclinical investigation of the therapeutic efficacy of microRNA-107 (miR-107). MATERIALS AND METHODS: The effects of miR-107 on cell proliferation and target gene expression were studied. Combinatorial effects of miR-107 and parthenolide were evaluated. RESULTS: Cell proliferation was repressed in A549 NSCLC cells transfected with miR-107. Inhibitor of nuclear factor kappa B kinase subunit gamma was directly targeted by miR-107. Overexpression of miR-107 in A549 cells sensitized them to parthenolide along with a marked reduction of cyclin-dependent kinase 2. CONCLUSION: Our findings unveil an important biological function of miR-107 in regulating lung cancer cell proliferation and elevating an antiproliferative effect of parthenolide on lung cancer cells, suggesting that miR-107 could be beneficial benefit treatment for advanced NSCLC.