Glutamate receptor, ionotropic, N-methyl D-aspartate-associated protein 1, a potential target of miR-296, facilitates proliferation and migration of rectal cancer cells

Glutamate receptor, ionotropic, N‑methyl D‑aspartate‑associated protein 1 promotes colorectal cancer cell proliferation and metastasis, and is negatively regulated by miR‑296‑3p

N‑methyl D‑aspartate receptors (NMDARs) are closely associated with the development, growth and metastasis of cancer. Glutamate receptor, ionotropic, N‑methyl D‑aspartate‑associated protein 1 (GRINA) is a member of the of the NMDAR family, and its aberrant expression is associated with gastric cancer. However, the role of GRINA in colorectal cancer (CRC) is not completely understood. In the present study, expression profiles of GRINA in several CRC databases were obtained and further verified using clinical CRC samples. The effects of GRINA overexpression on CRC progression both in vivo and in vitro were assessed. Briefly, cell proliferation was detected using MTT assay, and cell migration and invasion ability were evaluated by wound healing and Transwell assay. In addition, the molecular mechanism underlying the upregulated expression of GRINA in CRC was investigated. The regulatory association between GRINA and miR‑296‑3p was detected by luciferase assay, reverse transcription‑quantitative PCR and western blotting. The results demonstrated that GRINA expression levels were significantly increased in tumor samples compared with those in healthy samples, and upregulated expression of GRINA was associated with a less favorable prognostic outcome in patients with CRC. GRINA overexpression significantly increased CRC cell proliferation, invasion and migration. Additionally, it was determined that GRINA was post‑transcriptionally regulated by microRNA (miR)‑296‑3p. Together, the results of the present study suggested the potential importance of the miR‑296‑3p/GRINA axis and highlighted potential novel targets for the management of CRC.

5-Hydroxytryptamine, Glutamate, and ATP: Much More Than Neurotransmitters

5-hydroxytryptamine (5-HT) is derived from the essential amino acid L-tryptophan. Although the compound has been studied extensively for its neuronal handling and synaptic actions, serotonin 5-HT receptors can be found extra-synaptically and not only in neurons but in many types of mammalian cells, inside and outside the central nervous system (CNS). In sharp contrast, glutamate (Glu) and ATP are better known as metabolism-related molecules, but they also are neurotransmitters, and their receptors are expressed on almost any type of cell inside and outside the nervous system. Whereas 5-hydroxytryptamine and Glu are key regulators of the immune system, ATP actions are more general. 5-hydroxytryptamine, ATP and Glu act through both G protein-coupled receptors (GPCRs), and ionotropic receptors, i.e., ligand gated ion channels. These are the three examples of neurotransmitters whose actions as holistic regulatory molecules are briefly put into perspective here.