GLUL stabilizes N-Cadherin by antagonizing β-Catenin to inhibit the progresses of gastric cancer

Glutamate-ammonia ligase(GLUL, also known as glutamine synthetase) is a crucial enzyme that catalyzes ammonium and glutamate into glutamine in the ATP-dependent condensation. Although GLUL plays a critical role in multiple cancers, the expression and function of GLUL in gastric cancer remain unclear. In the present study, we have found that the expression level of GLUL was significantly lower in gastric cancer tissues compared with adjacent normal tissues, and correlated with N stage and TNM stage, and low GLUL expression predicted poor survival for gastric cancer patients. Knockdown of GLUL promoted the growth, migration, invasion and metastasis of gastric cancer cells in vitro and in vivo, and vice versa, which was independent of its enzyme activity. Mechanistically, GLUL competed with β-Catenin to bind to N-Cadherin, increased the stability of N-Cadherin and decreased the stability of β-Catenin by alerting their ubiquitination. Furthermore, there were lower N-Cadherin and higher β-Catenin expression levels in gastric cancer tissues compared with adjacent normal tissues. GLUL protein expression was correlated with that of N-Cadherin, and could be the independent prognostic factor in gastric cancer. Our findings reveal that GLUL stabilizes N-Cadherin by antagonizing β-Catenin to inhibit the progress of gastric cancer.

Small-molecule agents for cancer immunotherapy

Cancer immunotherapy,exemplified by the remarkable clinical benefits of the immune checkpoint blockade and chimeric antigen receptor T-cell therapy,is revolutionizing cancer therapy.They induce long-term tumor regression and overall survival benefit in many types of cancer.With the advances in our knowledge about the tumor immune microenvironment,remarkable progress has been made in the development of small-molecule drugs for immunotherapy.Small molecules targeting PRR-associated pathways,immune checkpoints,oncogenic signaling,metabolic pathways,cytokine/chemokine signaling,and immune-related kinases have been extensively investigated.Monotherapy of smallmolecule immunotherapeutic drugs and their combinations with other antitumor modalities are under active clinical investigations to overcome immune tolerance and circumvent immune checkpoint inhibitor resistance.Here,we review the latest development of small-molecule agents for cancer immunotherapy by targeting defined pathways and highlighting their progress in recent clinical investigations.

AHA1 upregulates IDH1 and metabolic activity to promote growth and metastasis and predicts prognosis in osteosarcoma

Osteosarcoma(OS)is the most common primary malignant bone tumor in children and adolescents.Although activator of HSP90 ATPase activity 1(AHA1)is reported to be a potential oncogene,its role in osteosarcoma progression remains largely unclear.Since metabolism reprogramming is involved in tumorigenesis and cancer metastasis,the relationship between AHA1 and cancer metabolism is unknown.In this study,we found that AHA1 is significantly overexpressed in osteosarcoma and related to the prognosis of osteosarcoma patients.AHA1 promotes the growth and metastasis of osteosarcoma both in vitro and in vivo.Mechanistically,AHA1 upregulates the metabolic activity to meet cellular bioenergetic needs in osteosarcoma.Notably,we identifed that isocitrate dehydrogenase 1(IDH1)is a novel client protein of Hsp90 AHA1.Furthermore,the IDH1 protein level was positively correlated with AHA1 in osteosarcoma.And IDH1 overexpression could partially reverse the effect of AHA1 knockdown on cell growth and migration of osteosarcoma.Moreover,high IDH1 level was also associated with poor prognosis of osteosarcoma patients.This study demonstrates that AHA1 positively regulates IDH1 and metabolic activity to promote osteosarcoma growth and metastasis,which provides novel prognostic biomarkers and promising therapeutic targets for osteosarcoma patients.