Study of tumor transglutaminase 2 expression in gallbladder cancer - Is it a novel predictor of survival?

ATO Increases ROS Production and Apoptosis of Cells by Enhancing Calpain-Mediated Degradation of the Cancer Survival Protein TG2

Transglutaminase 2 (TG2) is a critical cancer cell survival factor that activates several signalling pathways to foster drug resistance, cancer stem cell survival, metastasis, inflammation, epithelial-mesenchymal transition, and angiogenesis. All-trans retinoic acid (ATRA) and chemotherapy have been the standard treatments for acute promyelocytic leukaemia (APL), but clinical studies have shown that arsenic trioxide (ATO), alone or in combination with ATRA, can improve outcomes. ATO exerts cytotoxic effects in a variety of ways by inducing oxidative stress, genotoxicity, altered signal transduction, and/or epigenetic modification. In the present study, we showed that ATO increased ROS production and apoptosis ratios in ATRA-differentiated NB4 leukaemia cells, and that these responses were enhanced when TG2 was deleted. The combined ATRA + ATO treatment also increased the amount of nuclear factor erythroid 2-related factor 2 (NRF2) transcription factor, an adaptive regulator of the cellular oxidative stress response, and calpain proteolytic activity, resulting in TG2 degradation and the reduced survival of WT leukaemia cells. We further showed that the induced TG2 protein expression was degraded in the MCF-7 epithelial cell line and primary peripheral blood mononuclear cells upon ATO treatment, thereby sensitising these cell types to apoptotic signals.

Prognostic Value of lncRNA NEAT1 as a New Biomarker in Digestive System Tumors: a Systematic Study and Meta-analysis

OBJECTIVE

Nuclear paraspeckle assembly transcript 1 (NEAT1), a newly found lncRNA, is found abnormally expressed in digestive system tumors. This meta-analysis aims to evaluate the effect of NEAT1 on digestive system tumors.

METHODS

An analysis was conducted to investigate NEAT1 expression in digestive system tumors from the PubMed, Embase, and Web of Science databases. The relationship between NEAT1 expression and patient overall survival (OS) and clinicopathology was evaluated by correlation analysis with the pooled hazard ratio (HR), 95% confidence interval (CI), and odds ratio (OR).

RESULTS

A total of 12 published studies were enrolled in this meta-analysis. The NEAT1 overexpression was significantly associated with poor OS (HR = 1.64, 95% CI:1.41-1.91, p < 0.05), lymphatic metastasis (OR = 2.70, 95% CI: 2.02-3.61, p < 0.05), distal metastasis (OR = 3.01, 95% CI: 1.97-4.59, p < 0.05) and advanced tumor stage (OR = 3.04, 95% CI: 2.32-3.99, p < 0.05). However, digestive system tumor patients with high NEAT1 expression was not related to the patients' age (OR = 0.91, 95% CI: 0.65-1.26, p = 0.561), gender (OR = 1.04, 95% CI: 0.81-1.33, p = 0.761), tumor size (OR = 1.84, 95% CI: 0.88-3.88, p = 0.106), and tumor differentiation (OR = 0.86, 95% CI: 0.51-1.44, p = 0.570).

CONCLUSION

Collectively, NEAT1 can be used as a potential biomarker to predict the prognosis of patients with digestive system tumors, which is worth verifying in clinical practice.