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The current need for novel antibiotics is especially acute for drug-resistant Gram-negative pathogens 1 , 2 . These microorganisms have a highly restrictive permeability barrier, which limits the penetration of most compounds 3 , 4 . As a result, the last class of antibiotics that acted against Gram-negative bacteria was developed in the 1960s 2 . We reason that useful compounds can be found in bacteria that share similar requirements for antibiotics with humans, and focus on Photorhabdus symbionts of entomopathogenic nematode microbiomes. Here we report a new antibiotic that we name darobactin, which was obtained using a screen of Photorhabdus isolates. Darobactin is coded by a silent operon with little production under laboratory conditions, and is ribosomally synthesized. Darobactin has an unusual structure with two fused rings that form post-translationally. The compound is active against important Gram-negative pathogens both in vitro and in animal models of infection. Mutants that are resistant to darobactin map to BamA, an essential chaperone and translocator that folds outer membrane proteins. Our study suggests that bacterial symbionts of animals contain antibiotics that are particularly suitable for development into therapeutics. Bacterial symbionts of animals may contain antibiotics that are particularly suitable for development into therapeutics; one such compound, darobactin, is active against important Gram-negative pathogens both in vitro and in animal models of infection.

BackgroundTo explore correlations between the clinical attributes of secondary bladder cancer and brachytherapy, we retrospectively reviewed our institutional database on patients with localized prostate cancer who underwent low-dose-rate brachytherapy (LDR-BT) or high-dose-rate brachytherapy (HDR-BT) with or without external beam radiation therapy (EBRT) or radical prostatectomy (RP).MethodsFrom October 2003 to December 2014, 2551 patients with localized prostate cancer were treated at our institution. Of these, data on 2163 were available (LDR-BT alone: n = 953; LDR-TB with EBRT: n = 181; HDR-BT with EBRT: n = 283; RP without EBRT: n = 746). The times of secondary bladder cancer development subsequent to radical treatment, and their clinical characteristics, were studied.ResultsAge-adjusted Cox’s regression analyses indicated that brachytherapy did not significantly impact the incidence of secondary bladder cancer. However, the pathological characteristics of such cancer differed between patients treated via brachytherapy and RP without EBRT; invasive bladder cancer was more common in such patients.ConclusionThe risk for secondary bladder cancer was not significantly increased after brachytherapy compared to non-irradiation therapy. However, brachytherapy patients exhibited a higher incidence of invasive bladder cancer. Therefore, meticulous follow-up is crucial for early detection and treatment of bladder cancer in such patients.

Background Tuberous sclerosis complex (TSC) is a rare autosomal dominant disorder forming hamartomas throughout the body. Facial angiofibromas (FAs) occur in 75% of TSC patients, which are often enlarged, impairing the appearance of the face, and reducing the patient’s quality of life (QOL). The aim of this study was to characterize the impact of topical sirolimus treatment on the health-related QOL in patients with FA associated with TSC. Methods We investigated a total of 33 patients who received sirolimus gel treatment for FA associated with TSC and assessed the changes in the health-related QOL using the Medical Outcomes Study 36-Item Short Form (SF-36) Health Survey. SF-36 surveys were performed before and after 3 months of treatment. The conditions of the patients after using the sirolimus gel were categorized into the following three categories: “improved,” “unchanged,” and “aggravated.” Adverse events were investigated using the CTCAE v5.0-JCOG. Results The median age of the patients was 25 (range 14–55) years. After 3 months of sirolimus gel treatment, three scale scores of the SF-36, vitality (VT), social function (SF), and mental health (MH), were significantly improved compared to before the treatment. The VT and SF in patients who had improved FA were significantly better than those in the other patients. There were no significant differences in any scale scores between patients with and without adverse events at 3 months after the initiation of sirolimus gel treatment. Conclusions This is the first report regarding improved health-related quality of life in patients treated with sirolimus gel for FA associated with TSC by using the SF-36. The three scale scores associated with mental health were significantly improved compared to before the treatment. The health-related QOL in patients receiving sirolimus gel treatment is more strongly affected by the treatment efficacy than adverse events. Mini-abstract Sirolimus gel treatment improves the health-related QOL in patients with FA associated with TSC.

Lincomycin forms cross-links within the peptidyl transferase loop region of the 23S ribosomal RNA (rRNA) of the 50S subunit of the bacterial ribosome, which is the site of peptide bond formation, thereby inhibiting protein synthesis. We have previously reported that lincomycin at concentrations below the minimum inhibitory concentration potentiates the production of secondary metabolites in actinomycete strains, suggesting that activation of these strains by utilizing the dose-dependent response of lincomycin could be used to effectively induce the production of cryptic secondary metabolites. Here, we aimed to elucidate the fundamental mechanisms underlying lincomycin induction of secondary metabolism in actinomycetes. In the present study, the dose-dependent response of lincomycin on gene expression of the model actinomycete Streptomyces coelicolor A3(2) and possible relationships to secondary metabolism were investigated. RNA sequencing analysis indicated that lincomycin produced enormous changes in gene expression profiles. Moreover, reverse transcription PCR and/or comparative proteome analysis revealed that in S. coelicolor A3(2), lincomycin, which was used at concentrations for markedly increased blue-pigmented antibiotic actinorhodin production, rapidly enhanced expression of the gene encoding the lincomycin-efflux ABC transporter, the 23S rRNA methyltransferase, and the ribosome-splitting factor to boost the intrinsic lincomycin resistance mechanisms and to reconstruct the probably stalled 70S ribosomes with lincomycin; and in contrast temporarily but dramatically reduced mRNA levels of housekeeping genes, such as those encoding FoF1 ATP synthase, RNA polymerase, ribosomal proteins, and transcription and translation factors, with an increase in intracellular NTPs. A possible mechanism for lincomycin induction of secondary metabolism in S. coelicolor A3(2) is discussed on the basis of these results.

Vascular endothelial cell growth factor receptor 2 (VEGFR2) is an essential receptor for the homeostasis of endothelial cells. In this study, we showed that NEDD8-conjugated Cullin3 (CUL3)-based ubiquitin E3 (UbE3) ligase plays a crucial role in VEGFR2 mRNA expression. Human umbilical vein endothelial cells treated with MLN4924, an inhibitor of NEDD8-activating enzyme, or with CUL3 siRNA drastically lost their response to VEGF due to the intense decrease in VEGFR2 expression. Moreover, speckle-type POZ protein (SPOP) and death-domain associated protein (DAXX) were involved in the CUL3 UbE3 ligase complex as a substrate adaptor and a substrate, respectively. Knockdown of SPOP and CUL3 led to the upregulation of DAXX protein and downregulation of VEGFR2 levels. These levels were inversely correlated with one another. In addition, simultaneous knockdown of SPOP and DAXX completely reversed the downregulation of VEGFR2 levels. Moreover, the CUL3-SPOP-DAXX axis had the same effects on NOTCH1, DLL4 and NRP1 expression. Taken together, these findings suggest that the CUL3-SPOP-DAXX axis plays a very important role in endothelial cell function by targeting key angiogenic regulators.

Drug-resistant Gram-negative bacteria have become the major problem driving the antimicrobial resistance crisis. Searching outside the overmined actinomycetes, we focused on Photorhabdus , gut symbionts of enthomopathogenic nematodes that carry up to 40 biosynthetic gene clusters coding for secondary metabolites. With the overmining of actinomycetes for compounds acting against Gram-negative pathogens, recent efforts to discover novel antibiotics have been focused on other groups of bacteria. Teixobactin, the first antibiotic without detectable resistance that binds lipid II, comes from an uncultured Eleftheria terra , a betaproteobacterium; odilorhabdins, from Xenorhabdus , are broad-spectrum inhibitors of protein synthesis, and darobactins from Photorhabdus target BamA, the essential chaperone of the outer membrane of Gram-negative bacteria. Xenorhabdus and Photorhabdus are symbionts of the nematode gut microbiome and attractive producers of secondary metabolites. Only small portions of their biosynthetic gene clusters (BGC) are expressed in vitro. To access their silent operons, we first separated extracts from a small library of isolates into fractions, resulting in 200-fold concentrated material, and then screened them for antimicrobial activity. This resulted in a hit with selective activity against Escherichia coli , which we identified as a novel natural product antibiotic, 3′-amino 3′-deoxyguanosine (ADG). Mutants resistant to ADG mapped to gsk and gmk , kinases of guanosine. Biochemical analysis shows that ADG is a prodrug that is converted into an active ADG triphosphate (ADG-TP), a mimic of GTP. ADG incorporates into a growing RNA chain, interrupting transcription, and inhibits cell division, apparently by interfering with the GTPase activity of FtsZ. Gsk of the purine salvage pathway, which is the first kinase in the sequential phosphorylation of ADG, is restricted to E. coli and closely related species, explaining the selectivity of the compound. There are probably numerous targets of ADG-TP among GTP-dependent proteins. The discovery of ADG expands our knowledge of prodrugs, which are rare among natural compounds. IMPORTANCE Drug-resistant Gram-negative bacteria have become the major problem driving the antimicrobial resistance crisis. Searching outside the overmined actinomycetes, we focused on Photorhabdus , gut symbionts of enthomopathogenic nematodes that carry up to 40 biosynthetic gene clusters coding for secondary metabolites. Most of these are silent and do not express in vitro . To gain access to silent operons, we first fractionated supernatant from Photorhabdus and then tested 200-fold concentrated material for activity. This resulted in the isolation of a novel antimicrobial, 3′-amino 3′-deoxyguanosine (ADG), active against E. coli . ADG is an analog of guanosine and is converted into an active ADG-TP in the cell. ADG-TP inhibits transcription and probably numerous other GTP-dependent targets, such as FtsZ. Natural product prodrugs have been uncommon; discovery of ADG broadens our knowledge of this type of antibiotic.

BackgroundAlthough brachytherapy is a standard treatment option for patients with high-risk prostate cancer, only a few studies have compared low-dose-rate brachytherapy (LDR-BT) and high-dose-rate brachytherapy (HDR-BT). We applied propensity score-based inverse probability treatment weighting (IPTW) to compare oncological outcomes for LDR-BT and HDR-BT.MethodsWe retrospectively assessed prognosis in 392 patients with high-risk localized prostate cancer who had undergone brachytherapy plus external beam radiation. IPTW was applied to adjust the Kaplan–Meier survival analyses and Cox proportional hazards regression analyses, with the goal of minimizing bias from patient background.ResultsThe IPTW-adjusted Kaplan–Meier survival analyses showed no statistically significant differences for time to biochemical recurrence, clinical progression, castration-resistant prostate cancer, or death from any cause. The IPTW-adjusted Cox regression analyses also showed that the modality of brachytherapy was not an independent factor in these oncological outcomes. Notably, the two groups differed regarding complications; LDR-BT was associated with a higher rate of acute grade ≥ 2 GU toxicity, and late grade 3 toxicity was noted only in HDR-BT.ConclusionOur analysis of long-term outcomes in patients with high-risk localized prostate cancer shows no significant differences in oncological outcomes between LDR-BT and HDR-BT, but some differences in toxicity, and offers patients and clinicians useful information in deciding management strategies for high-risk localized prostate cancer.

BackgroundAlthough the optimal management of locally advanced prostate cancer (PCa) remains unclear, local definitive therapy, thus combined radiotherapy and androgen deprivation, is one option. We evaluated the long-term outcomes of patients with locally advanced PCa who underwent high-dose-rate brachytherapy (HDR-BT) and external beam radiation therapy (EBRT).MethodsWe retrospectively analyzed 173 patients with locally advanced PCa (cT3a-4N0-1M0) who underwent HDR-BT and EBRT. We employed Cox’s proportional hazards models to identify pre-treatment predictors of oncological outcomes. Treatment outcomes (biochemical recurrence-free survival [BCRFS], clinical progression-free survival [CPFS], and castration-resistant prostate cancer-free survival [CRPCFS] were compared according to the combination of the pre-treatment predictors.ResultsThe 5-year BCRFS, CPFS, and CRPCFS rates were 78.5, 91.7, and 94.4% respectively; there were two PCa deaths. Multivariate analysis revealed that the clinical T stage (cT3b and cT4) and Grade Group (GG) 5 status were independent risk factors for poor BCRFS, CPFS, and CRPCFS. In the GG ≤ 4 group, the Kaplan–Meier curves for BCRFS, CPFS, and CRPCFS revealed excellent outcomes. However, in the GG5 group, patients with cT3b and cT4 PCa evidenced significantly poorer oncological outcomes than those with cT3a PCa.ConclusionThe clinical T stage and GG status were significantly prognostic of oncological outcomes in patients with locally advanced PCa. In patients of GG ≤ 4 PCa, HDR-BT was effective even in patients with cT3b or cT4 PCa. However, in patients with GG5 PCa, careful monitoring is essential, particularly of patients with cT3b or cT4 PCa.

Background Despite not achieving statistical significance, the JAVELIN Renal 101 trial indicated a potentially clinically relevant effect size (hazard ratio [HR], 0.88; 95% confidence interval, 0.75 to 1.04) on overall survival (OS) favoring avelumab plus axitinib over sunitinib for advanced renal cell carcinoma (aRCC). To better interpret these findings, we performed a Bayesian evaluation. Methods We reanalyzed individual participant data from the JAVELIN Renal 101 trial using a Bayesian framework. Prior distributions were specified for varying levels of enthusiasm and skepticism for avelumab plus axitinib, and a prior from a meta‐analysis of similar trials. The posterior probability of any OS benefit with avelumab plus axitinib, Pr(HR < 1.0), and of benefit exceeding the minimal clinically important difference (MCID; HR = 0.75), Pr(HR < MCID), were estimated using Bayesian Cox models. Bayesian hierarchical models evaluated treatment effect heterogeneity across International Metastatic Renal Cell Carcinoma Database Consortium risk groups and programmed death‐ligand 1 (PD‐L1) status. Results Regardless of the prior assumptions used, Pr(HR < 1.0) was consistently high (93.0% to 95.5%). However, Pr(HR < MCID) was low (1.0% to 3.8%). Results were similar when the prior was informed by pooled data from similar trials. In subgroup analyses, Pr(HR < MCID) varied by risk group: 63.4% for poor‐risk, 34.9% for favorable‐risk, and 0.9% for intermediate‐risk aRCC. This probability was low regardless of PD‐L1 status. Conclusions This exploratory Bayesian reanalysis complements the interpretation of the JAVELIN Renal 101 trial and offers a probabilistic perspective beyond a dichotomous (i.e., significant/nonsignificant) interpretation.

BackgroundRecent clinical trials have reported improved disease-free survival rates of patients with stage pT3–4/ypT2–4 or pN + upper tract urothelial carcinoma (UTUC) on adjuvant nivolumab therapy. However, the appropriateness of the patient selection criteria used in clinical practice remains uncertain.MethodsWe retrospectively analyzed 895 patients who underwent nephroureterectomy to treat UTUC. The patients were divided into two groups: grade pT3–4 and/or pN + without neoadjuvant chemotherapy (NAC) or grade ypT2–4 and/or ypN + on NAC (adjuvant immunotherapy candidates) and others (not candidates for adjuvant immunotherapy). Kaplan–Meier curves were drawn to assess the oncological outcomes, including recurrence-free survival (RFS), cancer-specific survival (CSS), and overall survival (OS). Cox proportional hazards models were used to identify significant prognostic factors for oncological outcomes.ResultsThe Kaplan–Meier curves revealed notably inferior RFS, CSS, and OS of patients who were candidates for adjuvant immunotherapy. Multivariate analysis revealed that pathological T and N grade and lymphovascular invasion (LVI) status were independent risk factors for poor RFS, CSS, and OS.ConclusionIn total, 44.8% of patients were candidates for adjuvant immunotherapy. In addition to pathological T and N status, LVI was a significant predictor of survival, and may thus play a pivotal role in the selection of patients eligible for adjuvant immunotherapy.