MicroRNAs (miRNAs) are small non-coding RNA molecules, approximately 22 nucleotides in length that regulate gene translation through silencing or degradation of target mRNAs. They are involved in multiple biological processes, including differentiation and proliferation, metabolism, hemostasis, apoptosis or inflammation, and in the pathophysiology of many diseases. Numerous studies have suggested circulating miRNAs as promising diagnostic and prognostic biomarkers of many diseases.
miR-34a-5p is one of the most characterized tumor suppressor miRNAs in a variety of tumors and it plays a crucial role in regulating cancer-related processes, such as cell proliferation, apoptosis, epithelial-mesenchymal transition and metastasis. miR-34a-5p is downregulated in many tumours where it inhibits cell invasion and migration.
Primary colorectal cancer (CRC) tissues from patients showed lower miR-34a-5p expression when compared with matched non-tumour tissues. The expression level of miR-34a-5p in patients with p53-positive expression was higher than that in patients with p53-negative expression which indicates that the growth-inhibiting effect by miR-34a-5p was dependent on p53.
Expression of miR-34a was up-regulated in cancer tissue compared to adjacent tissue. High miR-34a expression was associated with better survival of patients. miR-34a showed lower expression levels in male patients with lymph node involvement, and a trend towards decreased expression in male patients with distant metastases. Male patients, but not female patients, with high expression of miR-34a and who were free of distant metastases and/or lymph node involvement showed better survival. miR-34a-5p was downregulated while lymphoid enhancer-binding factor 1 (LEF1) was upregulated in esophageal squamous cell carcinoma (ESCC) tissue and cell lines. Overexpression of miR-34a-5p could inhibit proliferation, migration, invasion and epithelial-mesenchymal transition (EMT) of ESCC cells.
Apigenin induces apoptosis through down-regulation of a zinc-finger transcription factor (SNAI1) by up-regulating miR-34a-5p in lung cancer cells.
- References to miR-34a-5p