Overexpression of Tripartite Motif-Containing 48 (TRIM48) Inhibits Growth of Human Glioblastoma Cells by Suppressing Extracellular Signal Regulated Kinase 1/2 (ERK1/2) Pathway.

BACKGROUND Herein, we found that tripartite motif-containing 48 (TRIM48) was reduced in human glioblastoma (GBM) cell lines. We investigated whether and how TRIM48 functions in human GBM in vitro. MATERIAL AND METHODS Human GBM cells (U87 MG and U138 MG) were infected with lentivirus to overexpress TRIM48, and 1 human GBM cell line (T98G) was infected with siRNAs to knock down TRIM48 expression. Techniques used included cell proliferation assay, measured by CCK-8 and BrdU-ELISA method, and cell cycle assay, determined using flow cytometry. Curcumin, a specific activator of extracellular signal regulated kinases (ERK1/2), or PD98059, a specific inhibitor of ERK1/2, was used to activate or block the ERK1/2 pathway, respectively. Expression of phosphorylated (p)-ERK1/2, and its downstream targets (Cyclin D1) were measured to assess the mechanism. RESULTS Our data suggest that overexpression of TRIM48 reduces the viability of U87 MG and U138 MG and leads to cell cycle arrest (in G0-G1 phase), which is associated with blockade of the ERK1/2 pathway and reduction of Cyclin D1. In contrast, knockdown of TRIM48 resulted in the opposite effects. Interestingly, the inhibitory effect of TRIM48 overexpression on human GBM cell growth and the inactivation of ERK1/2 were significantly alleviated with additional curcumin treatment, while it the promoted the effect of siTRIM48 on human GBM cell growth, and the activation of ERK1/2 was significantly alleviated with additional PD98059 treatment. CONCLUSIONS TRIM48 suppressed the growth of human GBM cell via the prevention of ERK1/2 activation.

Protective Effect of NGR1 against Glutamate-Induced Cytotoxicity in HT22 Hippocampal Neuronal Cells by Upregulating the SIRT1/Wnt/ß-Catenin Pathway.

Notoginsenoside R1 (NGR1) is an active compound isolated from Panax notoginseng. Despite the NGR1 having been used as a traditional medicine, little is known about the neuroprotective effects. In this study, we investigate the protective effects of NGR1 against glutamate-induced cytotoxicity in HT22 cells and its possible molecular mechanism. We assessed the toxicity of NGR1 and the protective activity by MTT assay. The levels of oxidative stress indices superoxide dismutase (SOD), glutathione (GSH), and mitochondrial membrane potential (MMP) were measured by the kits. The levels of reactive oxygen species (ROS) and Ca2+ concentration were measured by flow cytometry. Furthermore, we determined the expression of mitochondrial dysfunction related protein PINK1, Parkin, silent mating type information regulation 2 homolog-1 (sirtuin 1; SIRT1), and Wnt/ß-catenin by Western blotting. Here, we discovered that glutamate treatment led to cell viability loss, apoptosis facilitation, Ca2+ upregulation, MMP fluorescence intensity downregulation, and ROS generation of HT22 cells. In parallel, expression of Parkin was declined by glutamate. While, NGR1 treatment alleviated all the above phenomena. We further clarified that NGR1 alleviated glutamate-induced oxidative stress, apoptosis, and mitochondrial dysfunction by upregulating SIRT1 to activate Wnt/ß-catenin pathways. These findings demonstrate that NGR1 alleviated glutamate-induced cell damage, and NGR1 may play a protective role in neurological complications.

NLRP3 Promotes Glioma Cell Proliferation and Invasion via the Interleukin-1ß/NF-κB p65 Signals.

Because of the characteristics of high invasiveness, relapse, and poor prognosis, the management of malignant gliomas has always been a great challenge. Nod-like receptor (NLR) family pyrin domain containing 3 (NLRP3) is a crucial component of the NLRP3 inflammasome, a multiprotein complex that can trigger caspase 1/interleukin-1 (IL-1)-mediated inflammatory response once activated and participates in the pathogeny of diverse inflammatory diseases as well as cancers. We examined the function of NLRP3 in the development of glioma. Glioma cells were treated with NLRP3 interference or overexpression vectors, recombinant IL-1ß, IL-1ß antibody, and NF-κB inhibitor. Cell proliferation and invasion were assessed by CCK-8 and Transwell assays. Gene expression was detected by PCR, Western blot, and ELISA. NLRP3 and NF-κB p65 increased and were positively correlated in glioma tissues. NLRP3 knockdown suppressed glioma cell growth and invasion with the decrease of IL-1ß and NF-κB p65. Conversely, forced expression of NLRP3 promoted cell growth. NLRP3 silencing suppressed ectogenous IL-1ß-elevated cell proliferation and invasion, whereas IL-1ß elimination impaired the proproliferation effect of NLRP3 hyperexpression. Furthermore, NF-κB blockage abrogated IL-1ß and NLRP3 hyperexpression increased cell growth and invasion. NLRP3 promoted the growth and invasion of gliomas via the IL-1ß/NF-κB p65 signals.