NMDA receptor expression during cell transformation process at early stages of liver cancer in rodent models

Abstract

Hepatocellular carcinoma (HCC) is the most common primary liver cancer, which is not sensitive to radiotherapy and chemotherapy and very often experiences postoperative relapse. In this regard, effective screening of liver cancer is considered as the most important and urgent task. The aim of our study was to determine whether N-methyl-D-aspartate receptor (NMDAR) and, in particular, its subunits, can serve as biomarkers to distinguish the precancerous liver at early stages of liver fibrosis. We assessed the development of HCC after 10, 15 and 22 weeks using a HCC rat model. The expression of NMDAR subunits was monitored at different stages of HCC by means of immunohistochemistry combined with epifluorescence microscopy imaging, Western blotting and direct bisulfite sequencing. NMDAR subunits were not found in healthy liver tissues. In contrast, NMDAR subunits, in particular NR1 and NR2B, appeared at the stage of severe liver fibrosis (precancerous liver disease) in rats and were expressed during the development of HCC in rats and mice. Using the direct bisulfite sequencing, we detected that increased expression of NMDAR directly correlated with the demethylation of CpG islands in the promoter region of genes encoding receptor subunits. The obtained results confirmed that NMDAR subunits can serve as new biomarkers of precancerous liver disease, severe fibrosis, and its progression towards HCC.

Glutamatergic system components as potential biomarkers and therapeutic targets in cancer in non-neural organs

“…NMDAR2B transcriptional silencing by methylation was also found in non-small cell lung cancer, which correlates with some clinical features ( 55 ), whereas NMDAR1 and 2A-D expression was observed in hepatocellular carcinoma tissue from rat and mouse models ( 56 ). Interestingly, in this model NMDAR1 and NMDAR2B expression was identified since fibrosis, a precancerous stage of liver disease, correlated with demethylation in the promoter regions ( 56 ).…”

“…In this context, NMDAR2B emerges as a tumor suppressor gene since transfection of NMDAR1-1a and NMDAR2B significantly decreased viability and induced cell death by apoptosis of esophageal squamous cell carcinoma cell line KYSE140 in the presence of NMDA (132). NMDAR2B transcriptional silencing by methylation was also found in nonsmall cell lung cancer, which correlates with some clinical features (55), whereas NMDAR1 and 2A-D expression was observed in hepatocellular carcinoma tissue from rat and mouse models (56). Interestingly, in this model NMDAR1 and NMDAR2B expression was identified since fibrosis, a precancerous stage of liver disease, correlated with demethylation in the promoter regions (56).…”

“…Otherwise, increased expression of NMDAR1 and 2B was identified in hepatocellular carcinoma. This expression appeared from a precancerous stage of liver disease correlating with demethylation in CpG islands in the promoter regions in rat and mouse models of hepatocellular carcinoma ( 56 ). NMDAR2B emerges as a tumor suppressor gene since transfection of NMDAR1-1a and NMDAR2B significantly decreases viability and induces cell death by apoptosis of esophageal squamous cell carcinoma cell line KYSE140 in the presence of NMDA ( 132 ).…”

Transpiration of neurological phenomena in cancer: Long‐term depression (LTD) abrogates cancer stem cell memory and sensitizes it to metabolic therapy

“…21 An interesting research illuminates NMDAR expression as a biomarker for the transformation of pulmonary and liver fibrosis to cancer. 22 NMDAR expression can be modulated physically (electrophysiology/optogenetics) 23 or chemically to eventuate both LTP and LTD. 24 Postsynaptic calcium pulses 25 through these glutamate receptors marks as the deciding factor for driving the different pathways that result either in memory consolidation or memory impairment. 26 Small influx of calcium upon slight depolarization activates PKC⍺ and high-frequency stimulation triggers a large influx of calcium to activate the CREB pathway, both of which are NMDAR-dependent.…”

“…Moreover, NMDAR expression and, in particular, the NR2B subunit 19,20 owing to its delayed kinetics, has been shown to play a pivotal role in working memory function in the prefrontal cortex (PFC) and in regulating cancer singling pathways 21 . An interesting research illuminates NMDAR expression as a biomarker for the transformation of pulmonary and liver fibrosis to cancer 22 . NMDAR expression can be modulated physically (electrophysiology/optogenetics) 23 or chemically to eventuate both LTP and LTD 24 .…”