Discovery of N,N'-diarylurea molecules with activity against multidrug-resistant Staphylococcus aureus.

The emergence and global spread of methicillin-resistant Staphylococcus aureus (MRSA) pose a serious threat to public health, underscoring the urgent need for novel antibacterial interventions. Here, we screened 18 newly synthesized N,N'-diarylurea derivatives to identify compounds with activity against MRSA. Our investigations led to the discovery of a small molecule, SCB-24, which exhibited promising antimicrobial activity against MRSA USA300. Notably, SCB-24 demonstrated high activity even in the presence of 10% fetal bovine serum and showed excellent selectivity for bacterial over mammalian cells. SCB-24 also showed potent activity against various MRSA strains, including those resistant to second- and third-line antibiotics. Importantly, the efficacy of SCB-24 was inferior to that of vancomycin in MRSA-infected Galleria mellonella larvae. Overall, our findings suggest that SCB-24 has great potential as a new therapeutic for multidrug-resistant S. aureus infections.

Multipathway regulation induced by 4-(phenylsulfonyl)morpholine derivatives against triple-negative breast cancer.

Phenotypic drug discovery (PDD) is an effective drug discovery approach by observation of therapeutic effects on disease phenotypes, especially in complex disease systems. Triple-negative breast cancer (TNBC) is composed of several complex disease features, including high tumor heterogeneity, high invasive and metastatic potential, and a lack of effective therapeutic targets. Therefore, identifying effective and novel agents through PDD is a current trend in TNBC drug development. In this study, 23 novel small molecules were synthesized using 4-(phenylsulfonyl)morpholine as a pharmacophore. Among these derivatives, GL24 (4m) exhibited the lowest half-maximal inhibitory concentration value (0.90 µM) in MDA-MB-231 cells. To investigate the tumor-suppressive mechanisms of GL24, transcriptomic analyses were used to detect the perturbation for gene expression upon GL24 treatment. Followed by gene ontology (GO) analysis, gene set enrichment analysis (GSEA), and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis, multiple ER stress-dependent tumor suppressive signals were identified, such as unfolded protein response (UPR), p53 pathway, G2/M checkpoint, and E2F targets. Most of the identified pathways triggered by GL24 eventually led to cell-cycle arrest and then to apoptosis. In summary, we developed a novel 4-(phenylsulfonyl)morpholine derivative GL24 with a strong potential for inhibiting TNBC cell growth through ER stress-dependent tumor suppressive signals.

Flexible Construction Approach to the Synthesis of 1,5-Substituted Pyrrole-3-carbaldehydes from 5-Bromo-1,2,3-triazine.

We report an efficient and mild tandem catalytic process for the synthesis of functionalized pyrrole-3-carbaldehydes. These compounds were obtained by a one-pot three-component reaction of 5-bromo-1,2,3-triazine, terminal alkynes, and primary amines via a palladium-catalyzed Sonogashira coupling reaction, and then annulation through a silver-mediated reaction of the resulting alkynyl 1,2,3-triazines allowed for access to the multifunctionalized pyrrole-3-carbaldehydes.

A novel AMPK activator shows therapeutic potential in hepatocellular carcinoma by suppressing HIF1α-mediated aerobic glycolysis.

Hepatocellular carcinoma (HCC) is characterized by rapid growth, early vascular invasion, and high metastasis. Currently available US Food and Drug Administration (FDA)-approved drugs show low therapeutic efficacy, limiting HCC treatment to chemotherapy. We designed and synthesized a novel small molecule, SCT-1015, that allosterically activated adenosine monophosphate-activated protein kinase (AMPK) to suppress the aerobic glycolysis in HCC. SCT-1015 was shown to bind the AMPK α and ß-subunit interface, thereby exposing the kinase α domain to the upstream kinases, resulting in the increased AMPK activity. SCT-1015 dramatically reduced HCC cell growth in vitro and tumor growth in vivo. We further found that AMPK formed protein complexes with hypoxia-inducible factor 1-alpha (HIF1α) and that SCT-1015-activated AMPK promoted hydroxylation of HIF1α (402P and 564P), resulting in HIF1α degradation by the ubiquitin-proteasome system. With declined HIF1α abundance, many glycolysis-related enzymes were downregulated, suppressing aerobic glycolysis, and promoting oxidative phosphorylation. These results indicated that SCT-1015 channeled HCC cells into an unfavorable metabolic status. Overall, we reported SCT-1015 as a direct activator of AMPK signaling that held therapeutic potential in HCC.

Stabilization of AURKA by the E3 ubiquitin ligase CBLC in lung adenocarcinoma.

CBL family proteins (CBL, CBLB and CBLC in mammals) are E3 ubiquitin ligases of protein tyrosine kinases. CBL mediates the lysosomal degradation of activated EGFR through K63-linked ubiquitination, while CBLC has an oncogenic function by positively regulating EGFR activation through K6 and K11-linked ubiquitination in EGFR mutant lung adenocarcinoma (LAD). Here, we used immunoprecipitation and mass spectrometry to study the CBLC interactome, and found that CBLC is also involved in cell cycle regulation by stabilizing Aurora kinase A (AURKA). CBLC interacted with the kinase domain of AURKA and positively regulated the stability of AURKA by conjugating monoubiquitination and K11/K63-linked polyubiquitination, which are protective from degrading K11/K48 polyubiquitination. CBLC depletion markedly decreased the half-life of AURKA in cycloheximide-treated LAD cells. When LAD cells were synchronized with double thymidine block at the G1/S boundary and then released into mitotic arrest, CBLC depletion delayed the accumulation and activation of AURKA and prevented cancer cells from entering mitosis. CBLC deficiency significantly delayed cell cycle progression, reduced the mitotic population, and increased apoptosis of LAD cells. Targeting CBLC inhibited tumor growth of LAD cells and enhanced their sensitivity to paclitaxel in xenograft models. Immunohistochemical staining of the tissue microarray also revealed a positive correlation between the expression of CBLC and AURKA in normal and LAD tissues, further supporting the positive regulation of AURKA expression by CBLC. In summary, these findings indicate that the oncogenic E3 ligase CBLC plays a role in mitotic entry by stabilizing AURKA via ubiquitination in LAD. This work demonstrates that targeting CBLC combined with paclitaxel might be a potential option for the treatment of LAD patients who have no available targeted therapies.

Simeprevir Potently Suppresses SARS-CoV-2 Replication and Synergizes with Remdesivir.

The outbreak of coronavirus disease 2019 (COVID-19), caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is a global threat to human health. Using a multidisciplinary approach, we identified and validated the hepatitis C virus (HCV) protease inhibitor simeprevir as an especially promising repurposable drug for treating COVID-19. Simeprevir potently reduces SARS-CoV-2 viral load by multiple orders of magnitude and synergizes with remdesivir in vitro. Mechanistically, we showed that simeprevir not only inhibits the main protease (Mpro) and unexpectedly the RNA-dependent RNA polymerase (RdRp) but also modulates host immune responses. Our results thus reveal the possible anti-SARS-CoV-2 mechanism of simeprevir and highlight the translational potential of optimizing simeprevir as a therapeutic agent for managing COVID-19 and future outbreaks of CoV.

Alisertib inhibits migration and invasion of EGFR-TKI resistant cells by partially reversing the epithelial-mesenchymal transition.

Epithelial growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) have been widely used in the clinical treatment of non-small cell lung cancer (NSCLC) patients with EGFR mutations. Previous studies have shown that Aurora kinase A (AURKA) is overexpressed in a broad spectrum of cancer cells, which can induce epithelial-mesenchymal transition (EMT) and contribute to the occurrence of acquired EGFR-TKI resistance. However, whether the inhibition of AURKA could overcome EGFR-TKI resistance or reverse the EMT in TKI-resistant NSCLC cells remains unclear. In the current study, we established three EGFR-TKI-resistant cell lines and analyzed their expression profiles by RNA sequencing. The results revealed that the EMT pathway is significantly upregulated in the three cell lines with EGFR-TKI resistance. The phosphorylation of AURKA at Thr 288 was also upregulated, suggesting that the activation of AURKA plays an important role in the occurrence of EGFR-TKI resistance. Interestingly, the AURKA inhibitor, alisertib treatment restored the susceptibility of resistant cells to EGFR-TKIs and partially reversed the EMT process, thereby reducing migration and invasion in EGFR-TKI-resistant cells. This study provides evidence that targeting AURKA signaling pathway by alisertib may be a novel approach for overcoming EGFR-TKI resistance and for the treatment of metastatic EGFR-TKIs in NSCLC patients.

An updated review: Health outcomes in nursing home patients on dialysis.

Nursing home patients receiving dialysis are known to be an especially high-risk population due to advanced age and various co-morbidities. Previously, we reported the results of a large epidemiological study (n=3,943) using longitudinal data from an independent nursing home dialysis provider. The objective of the current study was to update the analyses of outcomes in dialysis patients in the nursing home setting using an observational epidemiological database with a larger population and more recent data. Health status and outcomes were evaluated for 6,314 patients who received hemodialysis treatinent in the nursing home setting between 2006 and. 2015. Analyses included monthly mortality rates, Kaplan-Meier survival analysis, and laboratory values. Patients had poor initial health status, with an incident first month annualized monthly mortality rate of 58%, mean hemoglobin of 10.0 g/dL, and mean serum albumin of 3.2 g/dL. Health status improved over time, with annual mortality rates in the range of 30% during months 4-12, and 21% during months 13-24. Mean serum albumin rose to approximately 3.5 g/dL and hemoglobin was stable at approximately 10.8 g/dl. Overall survival was 93%, 82%, 74%, and 63% at 1, 3, 6, and 12 months, respectively. These study results confirm our previous find- ings that nursing home patients on dialysis have poor initial health status. However, outcomes improved over time, and survival analyses indicate that long-term outcomes compare favorably to previously published studies of nursing home patients on dialysis.

Comparison of outcome of unilateral locking plate and dual plating in the treatment of bicondylar tibial plateau fractures.

BACKGROUND: Tibial plateau fracture (TPF) includes different fracture patterns with varied degrees of articular depression and displacement. Many kinds of fixators, including newly designed plate with locking screws, were applied to treat these complicated fractures. We intended to follow up the surgical outcomes of (1) unilateral locking plate, (2) classic dual plates, or (3) hybrid dual plates for TPF. MATERIALS AND METHODS: We retrospectively reviewed 76 patients with TPF, Schatzker types V and VI, who we operated from June 2006 to May 2009 in our institute. Excluding patients who expired due to other medical conditions and without complete follow-up, 45 patients were sorted out in this series. The scheme of surgical intervention was designed by visiting staff, and 15 patients, as group I, were treated with unilateral locking plate. The other 19 patients, as group II, were treated with classic dual plates. The residual 11 patients, as group III, were treated with hybrid dual plates (one lateral approach locking compression plate (LCP) + medial anti-gliding plate). All patients were under periodic F/U at about 6 weeks interval for at least 18 months postoperatively. RESULTS: In group I, 13 cases achieved solid bony union without obvious traumatic OA change, limitation of ROM, or malalignment. In groups II and III, 15 and 10 patients reached the same goal, respectively. By analysis of the recorded parameters with statistical software (SPSS 12.0), there were five parameters with significant difference, including Schatzker classification, operation time, staged treatment or not, hospitalization period, and hardware impingement. CONCLUSIONS: There was no significant statistical difference of union rate between these three groups in our series. Based on our clinical follow-up, several key points were emphasized: (1) Soft tissue problems should be kept in mind, and usage of locking plate can reduce the discomfort of hardware impingement effectively. (2) The single lateral approach technique for TPF with locking plate results in less operation time and shorter hospitalization period. (3) If the medial buttress cannot be established by reduction of the lateral fracture, then open reduction of the medial side is necessary and buttresses the medial fragment by dual plates.

The contribution of XRCC6/Ku70 to hepatocellular carcinoma in Taiwan.

BACKGROUND: Hepatocellular carcinoma (HCC) is a neoplasm for which the prevalence and mortality rates are very high in Taiwan. The DNA non-homologous end-joining repair gene XRCC6/Ku70 plays an important role in the repair of DNA double-strand breaks (DSBs) induced by both exogenous and endogenous DNA-damaging agents. Defects in overall DSB repair capacity can lead to genomic instability and carcinogenesis. In this study, we investigated the contribution of variant XRCC6 in relation to the risk of HCC, from the levels of DNA, RNA and protein. MATERIALS AND METHODS: In this hospital-based case-control study, we collected 298 patients with HCC and 298 cancer-free controls, with frequency matched by age and gender. Firstly, the associations of XRCC6 promoter T-991C (rs5751129), promoter G-57C (rs2267437), promoter A-31G (rs132770), and intron-3 (rs132774) polymorphisms with HCC risk in this Taiwanese population were evaluated. Secondly, 30 HCC tissue samples with variant genotypes were tested to estimate the XRCC6 mRNA expression by real-time quantitative reverse transcription. Finally, the HCC tissue samples of variant genotypes were examined by immunohistochemistry and western blotting to estimate their XRCC6 protein expression levels. RESULTS: Compared with the TT genotype, the TC and CC genotypes conferred a significantly increased risk of HCC [adjusted odds ratio (aOR)=2.43 and 3.52, 95% confidence interval (CI)=1.52-4.03 and 1.18-13.36, p=0.0003 and 0.0385, respectively]. The mRNA and protein expression levels in HCC tissues revealed statistically significantly lower XRCC6 mRNA and protein expressions in the HCC samples with TC/CC genotypes compared with those with the TT genotype (p=0.0037 and 0.0003, respectively). CONCLUSION: Our multi-approach findings at the DNA, RNA and protein levels suggested that XRCC6 may play an important role in HCC carcinogenesis in the Taiwanese population.

The role of XRCC6 T-991C functional polymorphism in renal cell carcinoma.

BACKGROUND: The DNA non-homologous end-joining repair gene XRCC6 (Ku70) plays a key role in both the DNA double-strand break (DSB) repair and cell cycle arrest. Defects in DSB repair capacity can lead to genomic instability. We hypothesized that a variant in the XRCC6 gene was associated with susceptibility to renal cell carcinoma (RCC). MATERIALS AND METHODS: In a hospital-based case-control study of 92 patients with RCC and 580 cancer-free controls, the frequency matched by age and sex, the associations of XRCC6 promoter T-991C (rs5751129), promoter G-57C (rs2267437), promoter A-31G (rs132770), and intron 3 (rs132774) polymorphisms with RCC risk were investigated in a Taiwanese population. At the same time, 30 adjacent renal tissue samples were tested to estimate the XRCC6 mRNA expression by real-time quantitative reverse transcription. RESULTS: Compared with the TT genotype, the TC genotype had a significantly increased risk of RCC [adjusted odds ratio=2.24, 95% confidence interval=1.25-4.08, p=0.0175]. The in vivo mRNA expression in renal tissues revealed a statistically significant lower XRCC6 mRNA expression in samples with TC/CC genotypes compared to those with the TT genotype (p=0.0039). CONCLUSION: These evidence suggests that the XRCC6 T-991C genotype together with its mRNA expression are involved in the etiology of RCC and may be a marker for susceptibility to RCC in the population of Taiwan.

Association of cyclin D1 genotypes with nasopharyngeal carcinoma risk.

AIM: The cell cycle regulator cyclin D1 (CCND1) is a critical regulator of the G1/S phase transition and plays an important part in several tumor types. This study aimed at investigating the association of CCND1 with and examining the interaction among CCND1 genotype and individual smoking habit in nasopharyngeal carcinoma susceptibility. PATIENTS AND METHODS: A total of 352 native Taiwanese consisting of 176 cases and 176 controls were enrolled in this hospital-based study, and CCND1 A870G (rs9344) and C1722G (rs678653) genotyping were analyzed by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and partially verified by direct sequencing. RESULTS: The results showed that there were significant differences between nasopharyngeal carcinoma and control groups in the distribution of the genotypic (p=0.0222) and allelic (p=0.0322) frequencies in the CCND1 A870G genotype. Individuals who carried at least one G allele (GG or AG) had a 0.71-fold lower risk of developing nasopharyngeal carcinoma compared to those who had the AA genotype (95% confidence interval=0.53-0.96). In addition, there is an obvious joint effect of CCND1 A870G genotype with smoking habit on nasopharyngeal carcinoma susceptibility. CONCLUSION: These findings support the conclusion that the cell cycle regulation may play a role in nasopharyngeal carcinoma development and that CCND1 A870G polymorphism maybe a useful biomarker for nasopharyngeal carcinoma progression.