Gαi1/3 mediate Netrin-1-CD146-activated signaling and angiogenesis.

Netrin-1 binds to the high-affinity receptor CD146 to activate downstream signaling and angiogenesis. Here, we examine the role and underlying mechanisms of G protein subunit alpha i1 (Gαi1) and Gαi3 in Netrin-1-induced signaling and pro-angiogenic activity. In mouse embryonic fibroblasts (MEFs) and endothelial cells, Netrin-1-induced Akt-mTOR (mammalian target of rapamycin) and Erk activation was largely inhibited by silencing or knockout of Gαi1/3, whereas signaling was augmented following Gαi1/3 overexpression. Netrin-1 induced Gαi1/3 association with CD146, required for CD146 internalization, Gab1 (Grb2 associated binding protein 1) recruitment and downstream Akt-mTOR and Erk activation. Netrin-1-induced signaling was inhibited by CD146 silencing, Gab1 knockout, or Gαi1/3 dominant negative mutants. Netrin-1-induced human umbilical vein endothelial cell (HUVEC) proliferation, migration and tube formation were inhibited by Gαi1/3 short hairpin RNA (shRNA), but were potentiated by ectopic Gαi1/3 overexpression. In vivo, intravitreous injection of Netrin-1 shRNA adeno-associated virus (AAV) significantly inhibited Akt-mTOR and Erk activation in murine retinal tissues and reduced retinal angiogenesis. Endothelial knockdown of Gαi1/3 significantly inhibited Netrin1-induced signaling and retinal angiogenesis in mice. Netrin-1 mRNA and protein expression were significantly elevated in retinal tissues of diabetic retinopathy (DR) mice. Importantly, silence of Netrin-1, by intravitreous Netrin-1 shRNA AAV injection, inhibited Akt-Erk activation, pathological retinal angiogenesis and retinal ganglion cells degeneration in DR mice. Lastly, Netrin-1 and CD146 expression is significantly increased in the proliferative retinal tissues of human proliferative diabetic retinopathy patients. Together, Netrin-1 induces CD146-Gαi1/3-Gab1 complex formation to mediate downstream Akt-mTOR and Erk activation, important for angiogenesis in vitro and in vivo.

G protein inhibitory α subunit 2 is a molecular oncotarget of human glioma.

Identification of novel therapeutic oncotargets for human glioma is extremely important. Here we tested expression, potential functions and underlying mechanisms of G protein inhibitory α subunit 2 (Gαi2) in glioma. Bioinformatics analyses revealed that Gαi2 expression is significantly elevated in human glioma, correlating with poor patients' survival, higher tumor grade and wild-type IDH status. Moreover, increased Gαi2 expression was also in local glioma tissues and different glioma cells. In primary and immortalized (A172) glioma cells, Gαi2 shRNA or knockout (KO, by Cas9-sgRNA) potently suppressed viability, proliferation, and mobility, and induced apoptosis. Ectopic Gαi2 overexpression, using a lentiviral construct, further augmented malignant behaviors in glioma cells. p65 phosphorylation, NFκB activity and expression of NFκB pathway genes were decreased in Gαi2-depleted primary glioma cells, but increased following Gαi2 overexpression. There was an increased binding between Gαi2 promoter and Sp1 (specificity protein 1) transcription factor in glioma tissues and different glioma cells. In primary glioma cells Gαi2 expression was significantly reduced following Sp1 silencing, KO or inhibition. In vivo studies revealed that Gαi2 shRNA-expressing AAV intratumoral injection hindered growth of subcutaneous glioma xenografts in nude mice. Moreover, Gαi2 KO inhibited intracranial glioma xenograft in nude mice. Gαi2 depletion, NFκB inhibition and apoptosis induction were observed in subcutaneous and intracranial glioma xenografts with Gαi2 depletion. Together, overexpressed Gαi2 is important for glioma cell growth possibly by promoting NFκB cascade activation.

Discovery of tetrahydrofuranyl spirooxindole-based SMYD3 inhibitors against gastric cancer via inducing lethal autophagy.

SMYD3 is a histone methyltransferase involved in transcriptional regulation, and its overexpression in various forms of cancer justifies that blocking SMYD3 functions can serve as a novel therapeutic strategy in cancer treatment. Herein, a series of novel tetrahydrofuranyl spirooxindoles were designed and synthesized based on a structure-based drug design strategy. Subsequent biochemical analysis suggested that these novel SMYD3 inhibitors showed good anticancer activity against stomach adenocarcinoma both in vitro and in vivo. Among them, compound 7r exhibited potent inhibitory capacities against SMYD3 and BGC823 cells with IC50 values of 0.81 and 0.75 µM, respectively. Mechanistic investigations showed that 7r could suppress Akt methylation and activation by SMYD3 and trigger lethal autophagic flux inhibition via the Akt-mTOR pathway. Collectively, our results may bridge the rational discovery of privileged structures, epigenetic targeting of SMYD3, and regulation of autophagic cell death.

Design, Synthesis, and Biological Evaluation of Pyrano[2,3-c]-pyrazole-Based RalA Inhibitors Against Hepatocellular Carcinoma.

The activation of Ras small GTPases, including RalA and RalB, plays an important role in carcinogenesis, tumor progress, and metastasis. In the current study, we report the discovery of a series of 6-sulfonylamide-pyrano [2,3-c]-pyrazole derivatives as novel RalA inhibitors. ELISA-based biochemical assay results indicated that compounds 4k-4r suppressed RalA/B binding capacities to their substrates. Cellular proliferation assays indicated that these RalA inhibitors potently inhibited the proliferation of HCC cell lines, including HepG2, SMMC-7721, Hep3B, and Huh-7 cells. Among the evaluated compounds, 4p displayed good inhibitory capacities on RalA (IC50 = 0.22 µM) and HepG2 cells (IC50 = 2.28 µM). Overall, our results suggested that a novel small-molecule RalA inhibitor with a 6-sulfonylamide-pyrano [2, 3-c]-pyrazole scaffold suppressed autophagy and cell proliferation in hepatocellular carcinoma, and that it has potential for HCC-targeted therapy.

Increased expression of PSME2 is associated with clear cell renal cell carcinoma invasion by regulating BNIP3­mediated autophagy.

Previous studies have showed that proteasome activator complex subunit 2 (PSME2) may play a role in some types of cancer. However, the involvement of PSME2 in clear cell renal cell carcinoma (ccRCC) remains unknown. The aim of the present study was to assess the poorly understood function of PSME2 expression in renal carcinoma. Using bioinformatics analysis, PSME2 mRNA expression profiles were investigated, along with its potential prognostic value and its functional enrichment. Signaling pathways and putative hub genes associated with PSME2 in ccRCC were identified. Based on the bioinformatics analysis results, immunohistochemistry of human ccRCC samples and renal carcinoma cell lines (CAKI­1 and 786­O) transfected with short interfering RNA targeting PSME2 were analyzed using western blot analysis, reverse transcription­quantitative PCR, immunofluorescence, and Cell Counting Kit­8, Transwell and transmission electron microscope assays. The results showed that when PSME2 expression was knocked down, the invasive abilities of the tumor cell lines were reduced, while autophagy was enhanced. The present study demonstrated that PSME2 was associated with the invasion ability of ccRCC cell lines by inhibiting BNIP3­mediated autophagy. In summary, PSME2 could be used as a prognostic factor and a promising therapeutic target in ccRCC.

[Inhibition of Microcystis aeruginosa by Bacillus subtilis fmb60 non-ribosome peptide metabolites].

Microcystis aeruginosa, a type of algal bloom microalgae, is widely distributed in water, causing serious deteriorated effects on humans and the ecological environment. As a biocontrol microorganism, Bacillus subtilis can synthesize various bioactive substances through non-ribosomal peptide synthetase, to inhibit the growth of M. aeruginosa. Thus, it is imperative to investigate the non-ribosomal peptide (NRP) metabolites of B. subtilis fmb60. Three NRP metabolites from B. subtilis fmb60 including bacillibactin, surfactin and fengycin were extracted and identified by genome mining technology. The growth inhibition of M. aeruginosa was studied by adding various concentrations of NRP metabolites. The half-effect concentration value (EC50.4 d) of M. aeruginosa was 26.5 mg/L after incubation for 4 days. With the increasing concentration, the inhibitory effects of NRP metabolites of B. subtilis fmb60 on M. aeruginosa was enhanced significantly. Compared with the control group, with the addition of 50 mg/L NRP metabolites to the M. aeruginosa, the content of Fv/Fm, Fv/Fo and Yield parameter after cultured for 4 days were decreased by 2.8%, 1.7% and 2.0%, respectively. Those findings indicate that the NRP metabolites of B. subtilis fmb60 can significantly inhibit the photosynthesis and metabolism of M. aeruginosa, which provides a theoretical foundation for the development of biological algae inhibitor of B. subtilis.

Discovery of novel TNNI3K inhibitor suppresses pyroptosis and apoptosis in murine myocardial infarction injury.

Myocardial infarction (MI) injury is a highly lethal syndrome that has, until recently, suffered from a lack of clinically efficient targeted therapeutics. The cardiac troponin I interacting kinase (TNNI3K) exacerbates ischemia-reperfusion (IR) injury via oxidative stress, thereby promoting cardiomyocyte death. In this current study, we designed and synthesized 35 novel TNNI3K inhibitors with a pyrido[4,5]thieno[2,3-d] pyrimidine scaffold. In vitro results indicated that some of the inhibitors exhibited sub-micromolar TNNI3K inhibitory capacity and good kinase selectivity, as well as cytoprotective activity, in an oxygen-glucose deprivation (OGD) injury cardiomyocyte model. Furthermore, investigation of the mechanism of the representative derivative compound 6o suggested it suppresses pyroptosis and apoptosis in cardiomyocytes by interfering with p38MAPK activation, which was further confirmed in a murine myocardial infarction injury model. In vivo results indicate that compound 6o can markedly reduce myocardial infarction size and alleviate cardiac tissue damage in rats. In brief, our results provide the basis for further development of novel TNNI3K inhibitors for targeted MI therapy.

Purification and characterization of chitin deacetylase active on insoluble chitin from Nitratireductor aquimarinus MCDA3-3.

The chitin deacetylase produced by marine strain Nitratireductor aquimarinus MCDA3-3 (NaCDA) was purified by using ammonium sulfate precipitation, Q Sepharose, and Superdex column chromatography. The purified NaCDA showed 75-fold purity, 50 U/mg specific activity with 28.5% yield. The purified CDA molecular weight was about 36 kDa. The temperature and pH of the purified enzyme were suiting at 30 °C and 8.0, respectively. The NaCDA was highly stable for a wide range of temperature 4 °C-25 °C and pH 6.0-9.0. Besides, increased enzyme activity was observed by introducing metal ions mainly Sr2+, Mg2+, and Na+. The enzyme was founded inhibited by Co2+, Ba2+, and EDTA at the value of 1 mM concentrations. On the other hand, NaCDA was shown an active activity behavior toward glycol chitin and chitin oligomers with a degree of polymerization more than four, any polymer below the chain such as trimer and dimer significantly reduce in the activity rate, and inactive with N-acetylglucosamine. Interestingly, NaCDA showed a high activity rate against insoluble chitins and converting acetyls to deacetylated. The reduction of acetyls from 56.26% and 22.88% of acetyl groups from ɑ-chitin and ß-chitin, respectively. Hence, the NaCDA would be applicable in production chitosan toward mass production.