The role of m6A methylation in targeted therapy resistance in lung cancer.

Targeted therapies have greatly improved clinical outcomes for patients with lung cancer (LC), but acquired drug resistance and disease relapse inevitably occur. Increasingly, the role of epigenetic mechanisms in driving acquired drug resistance is appreciated. In particular, N6-methyladenosine (m6A), one of the most prevalent RNA modifications, has several roles regulating RNA stability, splicing, transcription, translation, and destruction. Numerous studies have demonstrated that m6A RNA methylation can modulate the growth and invasion of cancer cells as well as contribute to targeted therapy resistance in LC. In this study, we outline what is known regarding the function of m6A in the acquisition of targeted therapy resistance in LC.

Burden of six major types of digestive system cancers globally and in China.

BACKGROUND: Digestive system cancers constitute a significant number of cancer cases, but their burden is not uniform. As Global Cancer Observatory (GLOBOCAN) 2022 has recently updated its estimates of cancer burden, we aimed to investigate the burden of six major digestive system cancers both worldwide and in China, along with geographical and temporal variations in cancer-specific incidence and mortality. METHODS: We extracted data on primary cancers of the esophagus, stomach, colorectum, liver, pancreas, and gallbladder from the GLOBOCAN database for 2022. Age-standardized incidence and mortality rates were calculated and stratified by sex, country, region, and human development index (HDI). We used the 2022 revision of the World Population Prospects (United Nations) to obtain demographic data for various age groups in China from 1988 to 2012 and used the joinpoint model and the average annual percentage change (AAPC) to analyze cancer incidence trends in China. RESULTS: In 2022, the estimated global incidence of digestive system cancers reached 4,905,882, with an estimated 3,324,774 cancer-related deaths. Colorectal cancer was most prevalent in terms of incidence and mortality. There was a significant correlation between the burden of gastrointestinal cancers and country HDI. From 1988 to 2012, the incidence of esophageal, gastric, and liver cancers declined in China, whereas colorectal and pancreatic cancer incidences continued to increase. By 2050, colorectal and liver cancers are projected to remain the leading cancer types in China in terms of incidence and mortality, respectively. CONCLUSIONS: Digestive system cancers remain a significant public health challenge globally and in China. Although progress has been made in the prevention and control of some cancers, the burden of digestive system cancers persists. The implementation of tertiary prevention strategies must be intensified to reduce the incidence and mortality of digestive system cancers, mitigating their impact on public health.

Cystathionine γ-lyase-derived H2S negatively regulates thymic egress via allosteric inhibition of sphingosine-1-phosphate lyase.

Thymic egress is a crucial process for thymocyte maturation, strictly regulated by sphingosine-1-phosphate lyase (S1PL). Recently, cystathionine γ-lyase (CSE), one of the enzymes producing hydrogen sulfide (H2S), has emerged as a vital immune process regulator. However, the molecular connection between CSE, H2S and thymic egress remains largely unexplored. In this study, we investigated the regulatory function of CSE in the thymic egress of immune cells. We showed that genetic knockout of CSE or pharmacological inhibition by CSE enzyme inhibitor NSC4056 or D,L-propargylglycine (PAG) significantly enhanced the migration of mature lymphocytes and monocytes from the thymus to the peripheral blood, and this redistribution effect could be reversed by treatment with NaHS, an exogenous donor of H2S. In addition, the CSE-generated H2S significantly increased the levels of S1P in the peripheral blood, thymus and spleen of mice, suppressed the production of proinflammatory cytokines and rescued pathogen-induced sepsis in cells and in vivo. Notably, H2S or polysulfide inhibited S1PL activity in cells and an in vitro purified enzyme assay. We found that this inhibition relied on a newly identified C203XC205 redox motif adjacent to the enzyme's active site, shedding light on the biochemical mechanism of S1PL regulation. In conclusion, this study uncovers a new function and mechanism for CSE-derived H2S in thymic egress and provides a potential drug target for treating S1P-related immune diseases.

The effects of probiotics supplementation on Helicobacter pylori standard treatment: an umbrella review of systematic reviews with meta-analyses.

Helicobacter pylori infection, a worldwide health issue, is typically treated with standard antibiotic therapies. However, these treatments often face resistance and non-compliance due to side effects. In this umbrella review, we aimed to comprehensively assess the impact of probiotics supplementation in different preparations on Helicobacter pylori standard treatment. We searched PubMed, Embase and Cochrane Central Register of Controlled Trials in the Cochrane Library from inception to June 1, 2023, to identify systematic reviews with meta-analyses that focused on eradication rates, total side effects and other outcomes of interest. The most comprehensive meta-analysis was selected for data extraction. AMSTAR 2 was used to assess quality of meta-analyses. Overall, 28 unique meta-analyses based on 534 RCTs were included. The results suggests that probiotics supplementation with pooled probiotic strains was significantly associated with improved eradication rates (RR 1.10, 95% CI 1.06-1.14) and reduced risk of total side effects (RR 0.54, 95% CI 0.42-0.70) compared with standard therapy alone. Single-strained or multi-strained preparation of probiotics supplementation showed similar results. Despite Bifidobacterium spp. showing the highest potential for eradication, the study quality was critically low for most meta-analyses, necessitating further high-quality research to explore the optimal probiotic strains or their combinations for Helicobacter pylori treatment.aq_start?>Kindly check and confirm the edit made in article title.

Maternally inherited diabetes and deafness coexists with lipoprotein lipase gene mutation-associated severe hyperlipidemia that was resistant to fenofibrate and atorvastatin, but sensitive to bezafibrate: A case report.

Maternally inherited diabetes and deafness is a rare genetic disease mainly caused by a point mutation in mitochondrial deoxyribonucleic acid. Lipoprotein lipase gene mutations are associated with familial dyslipidemias, which are difficult to manage. We reported for the first time a case that had both maternally inherited diabetes and severe hyperlipidemia caused by lipoprotein lipase gene mutation (C.347(exon3)G>C) that was resistant to fenofibrate and atorvastatin. We were able to manage the patient's hyperlipidemia with bezafibrate, and her diabetes was well controlled with insulin. In conclusion, genetic testing is helpful in identifying rare and interesting cases when clinicians suspect inheritable diseases. Additionally, when one fibrate drug is ineffective in treating hyperlipidemia, it might be worthwhile trying another fibrate.

Novel Quinic Acid Glycerates from Tussilago farfara Inhibit Polypeptide GalNAc-Transferase.

The discovery of a bioactive inhibitor tool for human polypeptide N-acetylgalactosaminyl transferases (GalNAc-Ts), the initiating enzyme for mucin-type O-glycosylation, remains challenging. In the present study, we identified an array of quinic acid derivatives, including four new glycerates (1-4) from Tussilago farfara, a traditional Chinese medicinal plant, as active inhibitors of GalNAc-T2 using a combined screening approach with a cell-based T2-specific sensor and purified enzyme assay. These inhibitors dose-dependently inhibited human GalNAc-T2 but did not affect O-linked N-acetylglucosamine transferase (OGT), the other type of glycosyltransferase. Importantly, they are not cytotoxic and retain inhibitory activity in cells lacking elongated O-glycans, which are eliminated by the CRISPR/Cas9 gene editing tool. A structure-activity relationship study unveiled a novel quinic acid-caffeic acid conjugate pharmacophore that directs inhibition. Overall, these new natural product inhibitors could serve as a basis for developing an inhibitor tool for GalNAc-T2.

High-throughput tandem-microwell assay for ammonia repositions FDA-Approved drugs to inhibit Helicobacter pylori urease.

To date, little attempt has been made to develop new treatments for Helicobacter pylori (H. pylori), although the community is aware of the shortage of treatments for H. pylori. In this study, we developed a 192-tandem-microwell-based high-throughput assay for ammonia that is a known virulence factor of H. pylori and a product of urease. We could identify few drugs, that is, panobinostat, dacinostat, ebselen, captan, and disulfiram, to potently inhibit the activity of ureases from bacterial or plant species. These inhibitors suppress the activity of urease via substrate-competitive or covalent-allosteric mechanism, but all except captan prevent the antibiotic-resistant H. pylori strain from killing human gastric cells, with a more pronounced effect than acetohydroxamic acid, a well-known urease inhibitor and clinically used drug for the treatment of bacterial infection. This study offers several bases for the development of new treatments for urease-containing pathogens and to study the mechanism responsible for the regulation of urease activity.

Barriers to conducting deprescribing in the elderly population amid the COVID-19 pandemic.

Deprescribing aims to reduce polypharmacy, especially in the elderly population, in order to maintain or improve quality of life, reduce harm from medications, and limit healthcare expenditure. Coronavirus disease (COVID-19) is an infectious disease that has led to a pandemic and has changed the lives many throughout the world. The mode of transmission of this virus is from person to person through the transfer of respiratory droplets. Therefore, non-essential healthcare services involving direct patient interactions, including deprescribing, has been on hiatus to reduce spread. Barriers to deprescribing before the pandemic include patient and system related factors, such as resistance to change, patient's knowledge deficit about deprescribing, lack of alternatives for treatment of disease, uncoordinated delivery of health services, prescriber's attitudes and/or experience, limited availability of guidelines for deprescribing, and lack of evidence on preventative therapy. Some of these barriers can be mitigated by using the following interventions:patient education, prioritization of non-pharmacological therapy, incorporation of electronic health record (EHR), continuous prescriber education, and development of research studies on deprescribing. Currently, deprescribing cannot be delivered through in person interactions, so virtual care is a reasonable alternative format. The full incorporation of EHR throughout Canada can add to the success of this strategy. However, there are several challenges of conducting deprescribing virtually in the elderly population. These challenges include, but are not limited, to their inability to use technology, lack of literacy, lack of assistance from others, greater propensity for withdrawal effects, and increased risk of severe consequences, if hospitalized. Virtual care is the future of healthcare and in order to retain the benefits of deprescribing, additional initiatives should be in place to address the challenges that elderly patients may experience in accessing deprescribing virtually. These initiatives should involve teaching elderly patients how to use technology to access health services and with technical support in place to address any concerns.

Discovery of an Inhibitor for Bacterial 3-Mercaptopyruvate Sulfurtransferase that Synergistically Controls Bacterial Survival.

H2S-producing enzymes in bacteria have been shown to be closely engaged in the process of microbial survival and antibiotic resistance. However, no inhibitors have been discovered for these enzymes, e.g., 3-mercaptopyruvate sulfurtransferase (MST). In the present study, we identified several classes of inhibitors for Escherichia coli MST (eMST) through high-throughput screening of ∼26,000 compounds. The thiazolidinedione-type inhibitors were found to selectively bind to Arg178 and Ser239 residues of eMST but hardly affected human MST. Moreover, the pioglitazone of this class concentration dependently accumulates the 3-mercaptopyruvate substrate and suppresses the H2S and reactive sulfane sulfur products in bacteria. Importantly, pioglitazone could potentiate the level of reactive oxygen species in cellulo and consequently enhance the antimicrobial effects of gentamicin and macrophages in culture. This study has identified the bioactive inhibitor of eMST, paving the way for the pharmacological targeting of eMST to synergistically control the survival of E. coli.

Discovery of a Bioactive Inhibitor with a New Scaffold for Cystathionine γ-Lyase.

We identify three submicromolar inhibitors with new chemical scaffolds for cystathionine γ-lyase (CSE) by a tandem-well-based high-throughput assay. NSC4056, the most potent inhibitor with an IC50 of 0.6 µM, which is also known as aurintricarboxylic acid, selectively binds to Arg and Tyr residues of CSE active site and preferably inhibits the CSE activity in cells rather than cystathionine ß-synthase (CBS), the other H2S-generating enzyme. Moreover, NSC4056 effectively rescues hypotension in hemorrhagic shock rats.

A pharmacological probe identifies cystathionine ß-synthase as a new negative regulator for ferroptosis.

Cystathionine ß-synthase (CBS) is responsible for the first enzymatic reaction in the transsulfuration pathway of sulfur amino acids. The molecular function and mechanism of CBS as well as that of transsulfuration pathway remain ill-defined in cell proliferation and death. In the present study, we designed, synthesized and obtained a bioactive inhibitor CH004 for human CBS, which functions in vitro and in vivo. CH004 inhibits CBS activity, elevated the cellular homocysteine and suppressed the production of hydrogen sulfide in a dose-dependent manner in cells or in vivo. Chemical or genetic inhibition of CBS demonstrates that endogenous CBS is closely coupled with cell proliferation and cell cycle. Moreover, CH004 substantially retarded in vivo tumor growth in a xenograft mice model of liver cancer. Importantly, inhibition of CBS triggers ferroptosis in hepatocellular carcinoma. Overall, the study provides several clues for studying the interplays amongst transsulfuration pathway, ferroptosis and liver cancer.

The small molecule luteolin inhibits N-acetyl-α-galactosaminyltransferases and reduces mucin-type O-glycosylation of amyloid precursor protein.

Mucin-type O-glycosylation is the most abundant type of O-glycosylation. It is initiated by the members of the polypeptide N-acetyl-α-galactosaminyltransferase (ppGalNAc-T) family and closely associated with both physiological and pathological conditions, such as coronary artery disease or Alzheimer's disease. The lack of direct and selective inhibitors of ppGalNAc-Ts has largely impeded research progress in understanding the molecular events in mucin-type O-glycosylation. Here, we report that a small molecule, the plant flavonoid luteolin, selectively inhibits ppGalNAc-Ts in vitro and in cells. We found that luteolin inhibits ppGalNAc-T2 in a peptide/protein-competitive manner but not promiscuously (e.g. via aggregation-based activity). X-ray structural analysis revealed that luteolin binds to the PXP motif-binding site found in most protein substrates, which was further validated by comparing the interactions of luteolin with wild-type enzyme and with mutants using 1H NMR-based binding experiments. Functional studies disclosed that luteolin at least partially reduced production of ß-amyloid protein by selectively inhibiting the activity of ppGalNAc-T isoforms. In conclusion, our study provides key structural and functional details on luteolin inhibiting ppGalNAc-T activity, opening up the way for further optimization of more potent and specific ppGalNAc-T inhibitors. Moreover, our findings may inform future investigations into site-specific O-GalNAc glycosylation and into the molecular mechanism of luteolin-mediated ppGalNAc-T inhibition.

Novel inhibitors of human DOPA decarboxylase extracted from Euonymus glabra Roxb.

Dopamine, a biogenic amine with important biological functions, is produced from l-DOPA by DOPA decarboxylase (DDC). DDC is a potential target to modulate the production of dopamine in several pathological states. Known inhibitors of DDC have been used for treatment of Parkinson's disease but suffered low specificity and diverse side effects. In the present study, we identified and characterized a novel class of natural-product-based selective inhibitors for DDC from the extract of Euonymus glabra Roxb. by a newly developed high-throughput enzyme assay. The structures of these inhibitors are dimeric diarylpropane, a unique chemical structure containing a divalent dopamine motif. The most effective inhibitors 5 and 6 have an IC50 of 11.5 ± 1.6 and 21.6 ± 2.7 µM in an in vitro purified enzyme assay, respectively, but did not inhibit other homologous enzymes. Compound 5 but not 6 dose-dependently suppressed the activity of hDDC and dopamine levels at low micromolar concentrations in cells. Furthermore, structure-activity relationship analyses revealed that p-benzoquinone might be a crucial moiety of these inhibitors for inhibiting hDDC. The natural-product-based selective inhibitors of hDDC could serve as a chemical lead for developing improved drugs for dopamine-related disease states.

High-throughput tandem-microwell assay identifies inhibitors of the hydrogen sulfide signaling pathway.

We report a high-throughput assay for H2S-producing enzymes, which is based on a newly designed tandem-well plate. Screening of 21,599 agents identified several potent inhibitors of cystathionine ß-synthase and cystathionine γ-lyase, the two key enzymes generating H2S in mammals, with IC50 values in the low two-digit micromolar range.

Structural insights into the homology and differences between mouse protein tyrosine phosphatase-sigma and human protein tyrosine phosphatase-sigma.

Protein tyrosine phosphatases PTP-sigma (PTPσ) plays an important role in the development of the nervous system and nerve regeneration. Although cumulative studies about the function of PTPσ have been reported, yet limited data have been reported about the crystal structure and in vitro activity of mouse PTPσ. Here we report the crystal structure of mouse PTPσ tandem phosphatase domains at 2.4 Å resolution. Then we compared the crystal structure of mouse PTPσ with human PTPσ and found that they are very similar, superimposing with a root mean square deviation of 0.45 Å for 517 equivalent Cα atoms. But some residues in mouse PTPσ form loops while corresponding residues in human PTPσ form ß-sheets or α-helices. Furthermore, we also compared in vitro activities of mouse PTPσ with human PTPσ and found that mouse PTPσ has 25-fold higher specific activity than human PTPσ does toward O-methyl fluorescein phosphate (OMFP) as the substrate. However, there is no significant activity difference between the mouse and the human enzyme detected with p-nitrophenylphosphate (pNPP) as the substrate. Mouse PTPσ and human PTPσ have different substrate specificities toward OMFP and pNPP as substrates. This work gives clues for further study of PTPσ.

Histone deacetylase inhibitor activity in royal jelly might facilitate caste switching in bees.

Worker and queen bees are genetically indistinguishable. However, queen bees are fertile, larger and have a longer lifespan than their female worker counterparts. Differential feeding of larvae with royal jelly controls this caste switching. There is emerging evidence that the queen-bee phenotype is driven by epigenetic mechanisms. In this study, we show that royal jelly--the secretion produced by the hypopharyngeal and mandibular glands of worker bees--has histone deacetylase inhibitor (HDACi) activity. A fatty acid, (E)-10-hydroxy-2-decenoic acid (10HDA), which accounts for up to 5% of royal jelly, harbours this HDACi activity. Furthermore, 10HDA can reactivate the expression of epigenetically silenced genes in mammalian cells. Thus, the epigenetic regulation of queen-bee development is probably driven, in part, by HDACi activity in royal jelly.

Synthesis and LAR inhibition of 7-alkoxy analogues of illudalic acid.

To obtain higher potency and specificity, a series of 7-alkoxy analogues of illudalic acid was synthesized on the base of structure-activity relationship (SAR). All of these compounds exhibited submicromolar inhibition of the enzyme when tested against human leukocyte common antigen-related phosphatase (LAR) (for example, for 15e, IC50 = 180 nmol x L(-1)). They represent the most potent small-molecule inhibitors of LAR so far. These analogues also display excellent selectivity for LAR over other protein tyrosine phosphatases (PTPs) except for the highly homologous PTPsigma. The compound 15f is of 120-fold selectivity for LAR versus PTP-1B inhibition. The development of potent enzyme-specific inhibitors is so important that they may serve both as tools to study the role of LAR and as therapeutic agents for treatment of type II diabetes.

LGH00031, a novel ortho-quinonoid inhibitor of cell division cycle 25B, inhibits human cancer cells via ROS generation.

AIM: To discover novel cell division cycle 25 (CDC25) B inhibitors and elucidate the mechanisms of inhibition in cancer cells. METHODS: Cell growth inhibition was detected by MTT assay, the cell cycle was analyzed by flow cytometry, and protein expression and phosphorylation was examined by Western blot analysis. RESULTS: LGH00031 inhibited CDC25B irreversibly in vitro in a dose-dependent manner, and impaired the proliferation of tumor cell lines. In synchronized HeLa cells, LGH00031 delayed the cell cycle progression at the G(2)/M phase. LGH00031 increased cyclin-dependent kinase 1 (CDK1) tyrosine 15 phosphorylation and cyclin B1 protein level. The activity of LGH00031 against CDC25B in vitro relied on the existence of 1,4-dithiothreitol (DTT) or dihydrolipoic acid and oxygen. The oxygen free radical scavenger catalase and superoxide dismutase reduced the inactivation of CDC25 by LGH00031, confirming that reactive oxygen species (ROS) mediate the inactivation process in vitro. LGH00031 accelerated cellular ROS production in a dose-dependent manner, and N-acetyl cysteine (NAC) markedly decreased the ROS production induced by LGH00031. Correspondingly, the LGH00031-induced decrease in cell viability and cell cycle arrest, cyclin B1 protein level, and phosphorylation of CDK1 tyrosine 15 were also rescued by NAC that decreased ROS production. CONCLUSION: The activity of LGH00031 at the molecular and cellular level is mediated by ROS.

Discovery and characterization of a novel inhibitor of CDC25B, LGH00045.

AIM: Cell division cycle 25 (CDC25) phosphatases have recently been considered as potential targets for the development of new cancer therapeutic agents. We aimed to discover novel CDC25B inhibitors in the present study. METHODS: A molecular level high-throughput screening (HTS) assay was set up to screen a set of 48000 pure compounds. RESULTS: HTS, whose average Z' factor is 0.55, was finished and LGH00045, a mixed-type CDC25B inhibitor with a novel structure and relative selectivity for protein tyrosine phosphatases, was identified. Furthermore, LGH00045 impaired the proliferation of tumor cells and increased cyclin-dependent kinase 1 inhibitory tyrosine phosphorylation. In synchronized HeLa cells, LGH00045 delayed cell cycle progression at the G2-M transition. CONCLUSION: LGH00045, a novel CDC25B inhibitor identified through HTS, showed good inhibition on the proliferation of tumor cells and affected the cell cycle progression, which makes it a good hit for further structure modification.