Expression profile and biological function of miR‑455‑5p in colorectal carcinoma

Abstract

Underexpression of microRNA-455-5p (miR-455-5p) in medullary thyroid carcinoma, melanoma, gastric cancer and additional cancer types has been reported, which may be associated with carcinoma development. The present study aimed to evaluate the expression profile and biological role of miR-455-5p in colorectal carcinoma. Carcinoma tissues and adjacent tissue specimens from 40 patients with colorectal cancer were randomly collected. Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) analysis was conducted to detect the expression levels of miR-455-5p in colorectal carcinoma and adjacent normal tissues. The biological effects of miR-455-5p on selected colorectal cancer cells were assessed using bromodeoxyuridine assays, wound healing migration assays and flow cytometry. Bioinformatics analysis was implemented to predict the potential target genes of miR-455-5p in colorectal cancer. The expression levels of target genes were further validated by RT-qPCR and western blot analysis of the mRNA and protein levels. The results of the experiments demonstrated that miR-455-5p expression was downregulated in colorectal cancer tissues compared with adjacent normal tissues. In colorectal cancer cells (SW-480, HT-29 and HCT-116), miR-455-5p was observed to inhibit cell proliferation and migration while promoting cell apoptosis. Bioinformatics analysis predicted that the oncogene phosphoinositide-3-kinase regulatory subunit 1 (PIK3R1) was one of the top ranked target genes of miR-455-5p in colorectal cancer cells. This association was validated by RT-qPCR and western blotting. In vivo studies revealed that the expression level of miR-455-5p was significantly downregulated in human colorectal cancer. Further in vitro studies suggested that miR-455-5p may prevent the development of colorectal cancer by downregulating the oncogene PIK3R1. It was concluded that miR-455-5p may target and downregulate PIK3R1 in colorectal cancer.

circPVT1 regulates medullary thyroid cancer growth and metastasis by targeting miR-455-5p to activate CXCL12/CXCR4 signaling

“…miR-455-5p is usually considered as a tumor suppressor since may studies show that its level is down-regulated in cancer tissues. For instance, in colorectal cancer, expression of miR-455-5p is sharply reduced and overexpression of miR-455-5p greatly inhibited colorectal cancer cell proliferation and migration [ 11 ]. In breast cancer, miR-455-5p has similar tumor suppressor effect [ 37 ].…”

“…By targeting CXCL12, circPVT1/miR-455-5p strongly affects MTC progression. Many other targets of miR-455-5p have been reported, such as galectin-9 and PIK3R1 and these interactions have been implicated in cancer development [ 11 , 50 ]. It will be interesting to examine whether those signaling pathways are involved in MTC as well.…”

“…In MTC, many aberrant expressions of miRNAs have been reported and one of them is miR-455-5p [ 10 ]. miR-455-5p has been shown to function as a tumor suppressor in many types of cancers such as colorectal cancer and prostate cancer [ 11 , 12 ]. For instance, miR-455-5p induced cell apoptosis and suppressed cancer cell migration and invasion in hepatocellular carcinoma via targeting IGF-1R [ 13 ].…”

PVT1 Long Non-coding RNA in Gastrointestinal Cancer

“…PVT1 seems to specifically bind to miR-455-5p (Figure 6). This miRNA is frequently downregulated in colorectal tumors and acts predominantly as a tumor suppressor element by targeting phosphoinositide-3-kinase regulatory subunit 1 (PIK3R1) and Runt-related transcription factor 2 (RUNX2), both crucial for the development of tumors (72,130,131) (Figure 5). An equivalent tumor suppressor role has been attributed to miR-455 in gastric tumorigenesis (132,133).…”

MiR‐455‐5p monitors myotube morphogenesis by targeting mylip

“…Interestingly, miR‐455‐5p was originally believed to be only a tumor suppressor 37 . However, increasing evidence has shown that miR‐455‐5p can be used as a prognostic indicator for gastrointestinal cancer, 31,38 liver cancer, 39 pancreatic cancer, 43 lung cancer, 32 breast cancer, 29 and prostate cancer 42 . In addition, miR‐455‐5p has been shown to play an anti‐inflammatory role in the immune system 26 .…”