Asymmetrical dimethylarginine antagonizes glutamate-induced apoptosis in PC12 cells

ADMA mediates gastric cancer cell migration and invasion via Wnt/β-catenin signaling pathway

Objective

To explore the role of ADMA in gastric cancer.

Methods

The specimens of 115 gastric cancer patients were analyzed by ELISA and survival analysis. Functional assays were used to assess the effects of ADMA on gastric cancer cells. Experiments were conducted to detect the signaling pathway induced by ADMA in GC.

Results

Gastric cancer patients with high ADMA levels had poor prognosis and low survival rate. Furthermore, high level of ADMA did not affect the proliferation while promoted the migration and invasion of gastric cancer cell. Moreover, ADMA enhanced the epithelial–mesenchymal transition (EMT). Importantly, ADMA positively regulated β-catenin expression in GC and promoted GC migration and invasion via Wnt/β-catenin pathway.

Conclusions

ADMA regulates gastric cancer cell migration and invasion via Wnt/β-catenin signaling pathway and which may be applied to clinical practice as a diagnostic and prognostic biomarker.

Electronic supplementary material

The online version of this article (10.1007/s12094-020-02422-7) contains supplementary material, which is available to authorized users.

Upregulation of CBS/H2S system contributes to asymmetric dimethylarginine-triggered protection against the neurotoxicity of glutamate to PC12 cells by inhibiting NOS/NO pathway

Glutamate-induced neurotoxicity involves in overproduction of nitric oxide (NO) and oxidative stress. Our previous data demonstrated that asymmetric dimethylarginine (ADMA), an endogenous nitric oxide synthase (NOS) inhibitor, has a protective effect against glutamate-induced neurotoxicity. Hydrogen sulfide (H2S), the third endogenous gaseous mediator, has potential therapeutic value for oxidative stress-induced neural damage. Therefore, we hypothesized that ADMA provides protection against the neurotoxicity of glutamate by regulating endogenous H2S generation. In the present study, we found that ADMA prevented glutamate-triggered decrease in endogenous H2S generation in PC12 cells and reversed glutamate-induced suppression in the expression and activity of cystathionine-β-synthetase (CBS), the predominant enzymatic source of H2S in PC12 cells. Furthermore, AOAA, a potent inhibitor of CBS, significantly abolished the protective action of ADMA against glutamate-induced neurotoxicity to PC12 cells. We also showed that ADMA suppressed glutamate-elicited NOS excessive activation and NO overproduction in PC12 cells. These data indicate that the protection of ADMA against glutamate-induced neurotoxicity is by promoting endogenous H2S generation, resulting from suppression in NOS excessive activation and NO overproduction. These findings provide a novel mechanism underlying the protection of ADMA against glutamate-induced neurotoxicity.

Asymmetric dimethylarginine attenuates serum starvation-induced apoptosis via suppression of the Fas (APO-1/CD95)/JNK (SAPK) pathway

Asymmetric dimethylarginine (ADMA) is synthesized by protein arginine methyltransferases during methylation of protein arginine residues and released into blood upon proteolysis. Higher concentrations of ADMA in blood have been observed in patients with metabolic diseases and certain cancers. However, the role of ADMA in colon cancer has not been well investigated. ADMA serum levels in human patients diagnosed with colon cancer were found to be higher than those present in healthy subjects. ADMA treatment of LoVo cells, a human colon adenocarcinoma cell line, attenuated serum starvation-induced apoptosis and suppressed the activation of the Fas (APO-1/CD95)/JNK (SAPK) (c-Jun N terminal protein kinase/stress-activated protein kinase)pathway. ADMA also suppressed the activation of JNK triggered by death receptor ligand anti-Fas mAb and exogenous C₂-ceramide. Moreover, we demonstrated that ADMA pretreatment protected LoVo cells from doxorubicin hydrochloride-induced cell death and activation of the Fas/JNK pathway. In summary, our results suggest that the elevated ADMA in colon cancer patients may contribute to the blocking of apoptosis of cancer cells in response to stress and chemotherapy.