MicroRNA-552 expression in colorectal cancer and its clinicopathological significance

MicroRNAs involved in colorectal cancer, a rapid mini-systematic review

INTRODUCTION

Colorectal cancer (CRC) involves the uncontrolled proliferation of glandular epithelial cells in the colon or rectum. The high mortality rate associated with CRC has driven extensive research into innovative diagnostic and therapeutic strategies. Among these, microRNAs (miRNA) have gained attention for their crucial role in regulating various cellular processes that contribute to the initiation, progression, and metastasis of CRC.

METHOD

This systematic review aimed to assess the roles of various miRNAs in CRC by analyzing multiple studies. The PICO framework was followed to structure the study regarding miRNA involved in CRC development and progression compared to normal cases. The outcomes were measured according miRNAs impact on CRC progression, survival rates, and treatment response. Systematic review of studies published from 2000 to November 2023 were included. Data were collected from prominent databases, including Google Scholar, PubMed, ScienceDirect, Irandoc, SID, and Magiran, covering studies from 2000 to November 2023. Studies were managed using EndNote for citation management, and duplicates were removed. The remaining studies were evaluated based on predefined inclusion and exclusion criteria.

RESULTS

In our review, we categorized 28 miRNAs based on their potential tumor suppressor or oncogenic effects in CRC progression. Among them, 14 miRNAs were highlighted as important based on the assessment using TCGA data, with miR-200a also showing a significant effect on patient survival.

CONCLUSION

This study compiled and analyzed validated miRNAs associated with CRC progression. The findings suggest the potential of these miRNAs as non-invasive biomarkers, which may be used alone or in combination with traditional tumor markers for improved diagnostic and prognostic applications in CRC. This review contributes novel insights by updating the current understanding and offering a comprehensive evaluation of miRNAs in CRC.

Blood miRNAs miR-549a, miR-552, and miR-592 serve as potential disease-specific panels to diagnose colorectal cancer

Introduction

miRNAs originating from colorectal cancer (CRC) tissue receive significant focus in the early diagnosis of CRC due to their stability in body fluids. However, if these miRNAs originated from alternative organs, their prognostic value will diminish. Thus, in this study, we aim to identify disease-specific miRNAs for colorectal cancer (CRC) by employing bioinformatics and experimental methodologies.

Method

To identify CRC-specific miRNAs, we retrieved miRNA profiles of CRC and normal tissues from the Cancer Genome Atlas (TCGA) database. Subsequently, computational strategies were utilized to select potential candidate miRNAs. Following this, the expression levels of the potent miRNAs were assessed through RT-qPCR in both CRC tissue and serum samples from patients (N = 46), as well as healthy individuals (N = 46). Additionally, the associations between clinicopathological characteristics, survival outcomes, and diagnostic accuracy were evaluated.

Results

A total of 8893 RNA-seq expression data were acquired from TCGA, comprising 8250 data from 19 distinct cancer types and 643 corresponding healthy samples. Based on the computational methodology, miR-549a, miR-552, and miR-592 were identified as the principal expressed miRNAs in colorectal cancer (CRC). Within these miRNAs, miR-552 displayed a substantial association with tumors at the N and T stages. miR-549a and miR-592 were observed to be linked exclusively to the invasion of tumor depth and tumor stage (TNM), respectively. The receiver operating characteristic (ROC) analysis conducted on the miRNA expression in serum samples revealed that all miRNAs exhibited an area under the ROC curve (AUC) of up to 0.86, thereby indicating their high diagnostic accuracy.

Conclusion

Considering the strong associations of these three identified miRNAs with CRC, they can collectively serve as a panel for specific discrimination of CRC from other types of cancer within the body. Although this study focused solely on CRC, this approach can potentially be applied to other cancer types as well.

Integration of TE Induces Cancer Specific Alternative Splicing Events

Alternative splicing of messenger RNA (mRNA) precursors contributes to genetic diversity by generating structurally and functionally distinct transcripts. In a disease state, alternative splicing promotes incidence and development of several cancer types through regulation of cancer-related biological processes. Transposable elements (TEs), having the genetic ability to jump to other regions of the genome, can bring about alternative splicing events in cancer. TEs can integrate into the genome, mostly in the intronic regions, and induce cancer-specific alternative splicing by adjusting various mechanisms, such as exonization, providing splicing donor/acceptor sites, alternative regulatory sequences or stop codons, and driving exon disruption or epigenetic regulation. Moreover, TEs can produce microRNAs (miRNAs) that control the proportion of transcripts by repressing translation or stimulating the degradation of transcripts at the post-transcriptional level. Notably, TE insertion creates a cancer-friendly environment by controlling the overall process of gene expression before and after transcription in cancer cells. This review emphasizes the correlative interaction between alternative splicing by TE integration and cancer-associated biological processes, suggesting a macroscopic mechanism controlling alternative splicing by TE insertion in cancer.