microRNA-34a/c function as tumor suppressors in Hep-2 laryngeal carcinoma cells and may reduce GALNT7 expression

Abstract

A family of small non-coding RNAs, ~22 nt in length, known as microRNAs (miRNAs), regulating ~30% of all human gene expression, have been reported to be involved in the pathogenesis of a number of types of cancers, including laryngeal squamous cell carcinoma (LSCC). In the current study, miR-34a and miR-34c were observed to be downregulated in human LSCC tissues. Ectopic expression of miR-34a and miR-34c in Hep-2 cells significantly induced the cell proliferation and migration ability in vitro. UDP-N-acetyl-α-D-galactosamine:polypeptide-N-acetylgalactosaminyltransferase 7 (GALNT7), whose expression is negatively regulated by miR-34a and miR-34c in Hep-2 cells, is confirmed to be a novel direct target gene of miR-34a and miR-34c. In conclusion, the current results suggest that miR-34a and miR-34c may function as tumor suppressors in LSCC through downregulation of GALNT7. The study of miR-34a, miR-34c and its novel target, GALNT7, may serve as novel potential makers for LSCC therapy.

MiR-34c induces apoptosis and inhibits the viability of M4e cells by targeting BCL2

“…Recent studies in cancer research have revealed that hsa-miR-34c is downregulated in human laryngeal squamous cell carcinoma tissues, and ectopic expression of miR-34a/c significantly induces the proliferative and migratory capacities of Hep-2 cells, in vitro (2). The imbalance between cell proliferation and apoptosis is a phenotypic characteristic of cancer, which is largely accountable for the pathogenesis of this disease.…”

“…Over the past decades, numerous miRNAs and genes have been verified to associate with and play crucial roles in regulating biological processes, including pathopoiesis and tumorigenesis (2,18,19). The target genes of these miRNAs, namely miR-34c (2), miR-196a (7), miR-221 (8), miR-203 (20), miR-27a (21) and miR-106b (22) have been reported to be associated with laryngeal carcinoma.…”

“…Inhibition of miR-221 in vitro increased the expression levels of Apaf-1 apoptotic pathway proteins, including caspase-3 and -9 (8). Furthermore, miR-34a/c expression was observed to be downregulated in human laryngeal squamous cell carcinoma tissues, and upregulation of miR-34a/c in Hep-2 cells by transfection significantly decreased cell proliferation and migratory ability in vitro (2). It was previously reported that B cell lymphoma 2 (BCL2), a central genetic apoptotic regulator (9), which is crucial for cell apoptosis, migration and invasion (3), is involved in the pathogenesis of laryngeal cancer (10)(11)(12).…”

“…Laryngeal cancer is a malignant cancer commonly occurring in the head and neck region, and was ranked as the sixth most frequent cancer worldwide in 2004 (1,2). However to date, the treatment strategy for laryngeal cancer is primarily surgery with radiotherapy.…”

“…Correspondingly, two genes and microRNAs (miRNA/miRs) are considered to be key biological factors in laryngeal cancer, including SOX2 (5), glucose transporter 1/3 (6), miR-196a (7), miR-221 (8) and miR-34a/c (2). miRNAs are small noncoding RNA molecules, which generally negatively regulate gene expression at the post-transcriptional level.…”