Discovery of selective inhibitors of Glutaminase-2, which inhibit mTORC1, activate autophagy and inhibit proliferation in cancer cells

Glutaminase, which converts glutamine to glutamate, is involved in Warburg effect in cancer cells. Two human glutaminase genes have been identified, GLS (GLS1) and GLS2. Two alternative transcripts arise from each glutaminase gene: first, the kidney isoform (KGA) and glutaminase C (GAC) for GLS; and, second, the liver isoform (LGA) and glutaminase B (GAB) for GLS2. While GLS1 is considered as a cancer therapeutic target, the potential role of GLS2 in cancer remains unclear. Here, we discovered a series of alkyl benzoquinones that preferentially inhibit glutaminase B isoform (GAB, GLS2) rather than the kidney isoform of glutaminase (KGA, GLS1). We identified amino acid residues in an allosteric binding pocket responsible for the selectivity. Treatment with the alkyl benzoquinones decreased intracellular glutaminase activity and glutamate levels. GLS2 inhibition by either alkyl benzoquinones or GLS2 siRNA reduced carcinoma cell proliferation and anchorage-independent colony formation, and induced autophagy via AMPK mediated mTORC1 inhibition. Our findings demonstrate amino acid sequences for selective inhibition of glutaminase isozymes and validate GLS2 as a potential anti-cancer target

Targeting a ribonucleoprotein complex containing the caprin-1 protein and the c-Myc mRNA suppresses tumor growth in mice: an identification of a novel oncotarget

Tylophorine compounds have been the focus of drug development for decades. Tylophorine derivatives exhibit anti-cancer activities but their cellular targets remain unknown. We used a biotinylated tylophorine derivative to probe for the interacting cellular target(s) of tylophorine. Tylophorine directly binds to caprin-1 and consequently enhances the recruitment of G3BP1, c-Myc mRNA, and cyclin D2 mRNA to form a ribonucleoprotein complex. Subsequently, this tylophorine targeted ribonucleoprotein complex is sequestered to the polysomal fractions and the protein expressions of the associated mRNA-transcripts are repressed. Caprin-1 depleted carcinoma cells become more resistant to tylophorine, associated with decreased formation of the ribonucleoprotein complex targeted by tylophorine. Consequently, tylophorine downregulates c-Myc and cyclins D1/D2, causing hypophosphorylation of Rb and suppression of both processing-body formation and the Warburg effect. Gene expression profiling and gain-of-c-Myc-function experiments also revealed that the downregulated c-Myc contributes to the anti-oncogenic effects of tylophorine compounds. Furthermore, the potent tylophorine derivative dibenzoquinoline-33b elicited a similar effect, as c-Myc protein levels were also decreased in xenograft tumors treated with dibenzoquinoline-33b. Thus, tylophorine compounds exert anti-cancer activity predominantly by targeting and sequestering the caprin-1 protein and c-Myc mRNA associated ribonucleoprotein complex

Tyrphostin AG1024 Suppresses Coronaviral Replication by Downregulating JAK1 via an IR/IGF-1R Independent Proteolysis Mediated by Ndfip1/2_NEDD4-like E3 Ligase Itch

JAK1 depletion or downregulation was previously reported to account for coronavirus inhibition. Here, we found that AG1024, an IR (insulin receptor) and IGF-1R (insulin-like growth factor 1 receptor) inhibitor, diminishes JAK1 protein levels and exerts anti-coronaviral activities with EC50 values of 5.2 ± 0.3 μM against transmissible gastroenteritis coronavirus (TGEV) and 4.3 ± 0.3 μM against human flu coronavirus OC43. However, although the IR and IGF-1R signaling pathways are activated by insulin or IGF-1 in swine testis cells, they are not triggered upon TGEV infection. AG1024, therefore, inhibits coronaviral replication and downregulates JAK1 protein levels independently of IR and IGF-1R. Moreover, JAK1 proteolysis caused by AG1024 was found through activation of upstream Ndfip1/2 and its effector NEDD4-like E3 ligase Itch. In addition, ouabain, which was reported to mediate JAK1 proteolysis causing anti-coronaviral activity by activation of Ndfip1/2 and NEDD4 E3 ligase, additively inhibited anti-coronaviral activity and JAK1 diminishment in combination with AG1024. This study provides novel insights into the pharmacological effects of AG1024 and Itch E3 ligase mediated JAK1 proteolysis and identified Ndfip1/2 as a cognate effector for JAK1 proteolysis via the diversified E3 ligases NEDD4 and NEDD4-like Itch. These findings are expected to provide valued information for the future development of anti-viral agents

Cytotoxic and Anti-HIV Principles from the Rhizomes of Begonia nantoensis

Three new compounds: begonanline (1), nantoamide (2) and methyl ( )-glycerate (3) as well as forty-four known compounds have been isolated and characterized from the rhizomes of . The structures of these compounds were determined by spectral analyses and/or X-ray crystallography. Among them, cucurbitacin B (4), dihydrocucurbitacin B (5), cucurbitacin E (6), dihydrocucurbitacin E (7), cucurbitacin I (8), and (−)-auranamide (9) showed cytotoxicity against four human cancer cell lines. 3β,22α-Dihydroxyolean-12-en-29-oic acid (10), indole-3-carboxylic acid (11), 5,7-dihydroxychromone (12), and (−)-catechin (13) demonstrated significant activity against HIV replication in H9 lymphocyte cells

Overactive Bladder during Pregnancy: A Prospective Longitudinal Study

Background and Objectives: Overactive bladder (OAB) is a serious urination-related symptom of unknown pathogenesis that affects one’s everyday activities. The objective of this study was to examine how OAB prevalence, symptom severity, and degree of distress caused by OAB symptoms evolved throughout the course of pregnancy. Materials and Methods: A total of 659 pregnant women were recruited from 2015 to 2020, and were evaluated through the International Consultation on Incontinence Questionnaire-Overactive Bladder (ICIQ-OAB) on OAB symptoms, administered in the early, middle, and late stages of pregnancy. Results: Generalized estimating equation analysis revealed that the odds of OAB occurring in the middle and late stages of pregnancy were 1.90 and 2.33 times higher, respectively, than in early pregnancy. The corresponding odds for OAB-wet were 1.63 and 2.07 higher, respectively, and the odds of OAB-dry occurring during late pregnancy were 0.80 higher than during early pregnancy. Symptoms were more severe by 0.07 and 0.21 points (on a 4-point scale) in the middle and late stages of pregnancy, respectively, than in early pregnancy; distress was greater by 0.13 and 0.27 points (on a 10-point scale) in the middle and late stages of pregnancy, respectively, than in early pregnancy. The prevalence of OAB, OAB-dry, and OAB-wet was significantly higher in early pregnancy than pre-pregnancy. Conclusions: The prevalence of OAB and OAB-wet increased over the course of pregnancy, but the prevalence of OAB-dry decreased. Furthermore, symptom severity and degree of distress increased over time

Polyketide Synthase Gene Expression in Relation to Chloromonilicin and Melanin Production in Monilinia fructicola

Monilinia fructicolais a fungal pathogen of worldwide significancethat causes brown rot of stone fruits. There are only few reports related tothe production of biologically active polyketides by this pathogen. In thisstudy, we examined an atypicalM. fructicolastrain TW5-4 that showsstrong antimicrobial activity against various plant pathogens. TW5-4 alsodisplays sparse growth in culture, low virulence, and higher levels ofmelanin compared with its albino mutant, TW5-4WM, and a wild-typestrain Mf13-81. Antifungal compounds were extracted from TW5-4 andpurified by thin-layer chromatography following visualization with an on-the-chromatogram inhibition assay. The principal antifungal compoundwas identified by linear ion trap mass spectrometry, high-resolutionelectro-spray ionization mass spectrometry, and proton nuclear mag-netic resonance analyses as the polyketide chloromonilicin. MultipleM. fructicolapolyketide synthase (PKS) sequences were then cloned bydegenerate PCR and inverse PCR. Sequence analyses support presence ofa 10-member PKS gene family in theM. fructicolagenome. Analyses ofPKS gene expression found no strong correlation between chloromoni-licin production in culture and transcript levels of any of the PKS genefamily members in mycelium of strains TW5-4, TW5-4WM, and Mf13-81. However,MfPKS12, a homolog ofBcPKS12involved in biosynthesisof 1,8-dihydroxynaphthalene (DHN)-melanin inBotrytis cinerea, wasstrongly expressed in mycelia of TW5-4 and Mf13-81. AnMfPKS12-silenced mutant accumulated significantly less melanin in mycelia, hadlower resistance to polyethylene glycol-induced osmotic stress, anddisplayed reduced virulence on nectarine fruit. The results suggest thatDHN-melanin is required for tolerance to osmotic stress and fullvirulence inM. fructicola