Evaluation of hypofractionated adaptive radiotherapy using the MR Linac in localised pancreatic cancer: protocol summary of the Emerald-Pancreas phase 1/expansion study located at Oxford University Hospital, UK.

INTRODUCTION: Online adaptive MR-guided radiotherapy allows for dose escalation to pancreatic cancer while sparing surrounding critical organs. We seek to evaluate the safety of delivering hypofractionated five-fraction, three-fraction and single-fraction MR-guided stereotactic ablative radiotherapy (SABR) to the pancreas. METHODS AND ANALYSIS: This is a single-centre three-arm phase 1 non-randomised safety study. Patients with localised pancreatic cancer will receive either 50 Gy in five (biological equivalent dose (BED10)=100 Gy), 39 Gy in three (BED10=90 Gy) or 25 Gy in a single fraction (BED10=87.5 Gy) MR-guided daily online adaptive radiotherapy. Each fractionation regimen will be assessed as independent cohorts to determine tolerability, assessed continuously using Bayesian conjugate posterior beta distributions. The primary endpoint of the study is to establish the safety of five-fraction, three-fraction and single-fraction MR-guided hypofractionation SABR in localised pancreatic cancer by assessing dose-limiting toxicities. Secondary endpoints include overall survival, progression-free survival, local control rates, overall control rate, resection rates, long-term toxicities and freedom from second-line chemotherapy. This study plans to also explore imaging and immune biomarkers that may be useful to predict outcome and personalise treatment. The trial will recruit up to 60 patients with a safety run-in. ETHICS AND DISSEMINATION: The trial is approved by the West Midlands-Black Country Research Ethics Committee 22/WM/0122. The results will be disseminated via conference presentations, peer-reviewed scientific journals and submission to regulatory authorities. The data collected for the study, including individual participant data, will be made available to researchers on request to the study team and with appropriate reason, via octo-enquiries@oncology.ox.ac.uk. The shared data will be deidentified participant data and will be available for 3 years following publication of the study. Data will be shared with investigator support, after approval of a proposal and with a signed data access agreement. TRIAL REGISTRATION NUMBER: ISRCTN10557832.

The oligometastatic paradigm and the role of radiotherapy.

Most cancer-related deaths are due to metastatic disease. There is now an emerging evidence base suggesting that a subgroup of metastatic patients benefit significantly from local resection (surgery) or ablation (stereotactic ablative body radiation, SABR) of their metastatic sites. These patients are in what has been termed the 'oligometastatic state', a transitional window between local and disseminated disease where locally ablative, metastasis-directed therapy prolongs progression-free survival, improves overall survival and sometimes achieves cure. Appropriately selecting those who fit this oligometastatic phenotype, while integrating advances in ablative technologies such as SABR with modern systemic treatments, is an evolving challenge for oncologists.

FLASHlab@PITZ: New R&D platform with unique capabilities for electron FLASH and VHEE radiation therapy and radiation biology under preparation at PITZ.

At the Photo Injector Test facility at DESY in Zeuthen (PITZ), an R&D platform for electron FLASH and very high energy electron radiation therapy and radiation biology is being prepared (FLASHlab@PITZ). The beam parameters available at PITZ are worldwide unique. They are based on experiences from 20 + years of developing high brightness beam sources and an ultra-intensive THz light source demonstrator for ps scale electron bunches with up to 5 nC bunch charge at MHz repetition rate in bunch trains of up to 1 ms length, currently 22 MeV (upgrade to 250 MeV planned). Individual bunches can provide peak dose rates up to 1014 Gy/s, and 10 Gy can be delivered within picoseconds. Upon demand, each bunch of the bunch train can be guided to a different transverse location, so that either a "painting" with micro beams (comparable to pencil beam scanning in proton therapy) or a cumulative increase of absorbed dose, using a wide beam distribution, can be realized at the tumor. Full tumor treatment can hence be completed within 1 ms, mitigating organ movement issues. With extremely flexible beam manipulation capabilities, FLASHlab@PITZ will cover the current parameter range of successfully demonstrated FLASH effects and extend the parameter range towards yet unexploited short treatment times and high dose rates. A summary of the plans for FLASHlab@PITZ and the status of its realization will be presented.

Implementation of Stereotactic MRI-Guided Adaptive Radiotherapy (SMART) for Hepatobiliary and Pancreatic Cancers in the United Kingdom - Fifty in Five.

The first MRIdian® MR linear accelerator (MR-Linac; ViewRay, Oakwood Village, Ohio) in the United Kingdom went live in December 2019 following a record installation time. Stereotactic MRI-guided Adaptive Radiotherapy (SMART) has since been implemented and has advantages of excellent soft tissue definition of both target and organs at risk (OARs), real-time target and OAR visualisation on cine-MRI, daily recontouring of target and critical OARs with live online plan adaptation/re-optimisation, and automatic respiratory-gated treatment delivery. We present a multi-disciplinary narrative and technical description of how this innovative technique was implemented for hepatobiliary (HPB) cancers. In particular, we explain how a collaborative approach and desire to push the boundaries and improve outcomes enabled 50 patients to be treated in the first five months, many with technically challenging tumours not always deliverable on other platforms. Physics, dosimetry, radiographer, and clinician perspectives on implementing SMART are presented. MRIdian® single fraction lung stereotactic ablative radiotherapy (SABR) will shortly be implemented along with innovative research in conjunction with our academic partners.

Safety and Treatment Outcomes of Nivolumab for the Treatment of Recurrent or Metastatic Head and Neck Squamous Cell Carcinoma: Retrospective Multicenter Cohort Study.

Nivolumab is an anti-PD-1 monoclonal antibody currently used as immunotherapy for patients with recurrent/metastatic head and neck squamous cell carcinoma (HNSCC) with evidence of disease progression after platinum-based chemotherapy. This study evaluates real-world safety and treatment outcomes of non-trial nivolumab use. A retrospective multicenter cohort study of patients with recurrent/metastatic HNSCC treated with nivolumab between January 2017 and March 2020 was performed. Overall, 123 patients were included. The median age was 64 years, the majority of patients were male (80.5%) and had a smoking history (69.9%). Primary outcomes included overall response rate (ORR) of 19.3%, median progression-free survival (PFS) of 3.9 months, 1-year PFS rate of 16.8%, a median overall survival (OS) of 6.5 months and 1-year OS rate of 28.6%. These results are comparable to the CHECKMATE-141 study. Of 27 patients who had PD-L1 status tested, positive PD-L1 status did not significantly affect PFS (p = 0.86) or OS (p = 0.84). Nivolumab was well tolerated with only 15.1% experiencing immune-related toxicities (IRT) and only 6.7% of patients stopping due to toxicity. The occurrence of IRT appeared to significantly affect PFS (p = 0.01) but not OS (p = 0.07). Nivolumab in recurrent/metastatic HNSCC is well tolerated and may be more efficacious in patients who develop IRT.

Sprouty2 positively regulates T cell function and airway inflammation through regulation of CSK and LCK kinases.

The function of Sprouty2 (Spry2) in T cells is unknown. Using 2 different (inducible and T cell-targeted) knockout mouse strains, we found that Spry2 positively regulated extracellular signal-regulated kinase 1/2 (ERK1/2) signaling by modulating the activity of LCK. Spry2-/- CD4+ T cells were unable to activate LCK, proliferate, differentiate into T helper cells, or produce cytokines. Spry2 deficiency abrogated type 2 inflammation and airway hyperreactivity in a murine model of asthma. Spry2 expression was higher in blood and airway CD4+ T cells from patients with asthma, and Spry2 knockdown impaired human T cell proliferation and cytokine production. Spry2 deficiency up-regulated the lipid raft protein caveolin-1, enhanced its interaction with CSK, and increased CSK interaction with LCK, culminating in augmented inhibitory phosphorylation of LCK. Knockdown of CSK or dislodgment of caveolin-1-bound CSK restored ERK1/2 activation in Spry2-/- T cells, suggesting an essential role for Spry2 in LCK activation and T cell function.

Discovery of Sisunatovir (RV521), an Inhibitor of Respiratory Syncytial Virus Fusion.

RV521 is an orally bioavailable inhibitor of respiratory syncytial virus (RSV) fusion that was identified after a lead optimization process based upon hits that originated from a physical property directed hit profiling exercise at Reviral. This exercise encompassed collaborations with a number of contract organizations with collaborative medicinal chemistry and virology during the optimization phase in addition to those utilized as the compound proceeded through preclinical and clinical evaluation. RV521 exhibited a mean IC50 of 1.2 nM against a panel of RSV A and B laboratory strains and clinical isolates with antiviral efficacy in the Balb/C mouse model of RSV infection. Oral bioavailability in preclinical species ranged from 42 to >100% with evidence of highly efficient penetration into lung tissue. In healthy adult human volunteers experimentally infected with RSV, a potent antiviral effect was observed with a significant reduction in viral load and symptoms compared to placebo.

Considerations for the treatment of pancreatic cancer during the COVID-19 pandemic: the UK consensus position.

The coronavirus disease 2019 (COVID-19) pandemic epicentre has moved to the USA and Europe, where it is placing unprecedented demands on healthcare resources and staff availability. These service constraints, coupled with concerns relating to an increased incidence and severity of COVID-19 among patients with cancer, should lead to re-consideration of the risk-benefit balance for standard treatment pathways. This is of particular importance to pancreatic cancer, given that standard diagnostic modalities such as endoscopy may be restricted, and that disease biology precludes significant delays in treatment. In light of this, we sought consensus from UK clinicians with an interest in pancreatic cancer for management approaches that would minimise patient risk and accommodate for healthcare service restrictions. The outcomes are described here and include recommendations for treatment prioritisation, strategies to bridge to later surgical resection in resectable disease and factors that modify the risk-benefit balance for treatment in the resectable through to the metastatic settings. Priority is given to strategies that limit hospital visits, including through the use of hypofractionated precision radiotherapy and chemoradiotherapy treatment approaches.

A phase 1 trial of the safety, tolerability and biological effects of intravenous Enadenotucirev, a novel oncolytic virus, in combination with chemoradiotherapy in locally advanced rectal cancer (CEDAR).

BACKGROUND: Chemoradiotherapy remains the standard of care for locally advanced rectal cancer. Efforts to intensify treatment and increase response rates have yet to yield practice changing results due to increased toxicity and/or absence of increased radiosensitization. Enadenotucirev (EnAd) is a tumour selective, oncolytic adenovirus which can be given intravenously. Pre-clinical evidence of synergy with radiation warrants further clinical testing and assessment of safety with radiation. METHODS: Eligibility include histology confirmed locally advanced rectal cancer that require chemoradiation. The trial will use a Time-to-Event Continual Reassessment Model-based (TiTE-CRM) approach using toxicity and efficacy as co-primary endpoints to recommend the optimal dose and treatment schedule 30 patients will be recruited. Secondary endpoints include pathological complete response the neoadjuvant rectal score. A translational program will be based on a mandatory biopsy during the second week of treatment for 'proof-of-concept' and exploration of mechanism. The trial opened to recruitment in July 2019, at an expected rate of 1 per month for up to 4 years. DISCUSSION: Chemoradiation with Enadenotucirev as a radiosensitiser in locally Advanced Rectal cancer (CEDAR) is a prospective multicentre study testing a new paradigm in radiosensitization in rectal cancer. The unique ability of EnAd to selectively infect tumour cells following intravenous delivery is an exciting opportunity with a clear translational goal. The novel statistical design will make efficient use of both toxicity and efficacy data to inform subsequent studies. TRIAL REGISTRATION: ClinicalTrial.gov, NCT03916510. Registered 16th April 2019.

Phase I trial of WEE1 inhibition with chemotherapy and radiotherapy as adjuvant treatment, and a window of opportunity trial with cisplatin in patients with head and neck cancer: the WISTERIA trial protocol.

INTRODUCTION: Patients with head and neck squamous cell carcinoma with locally advanced disease often require multimodality treatment with surgery, radiotherapy and/or chemotherapy. Adjuvant radiotherapy with concurrent chemotherapy is offered to patients with high-risk pathological features postsurgery. While cure rates are improved, overall survival remains suboptimal and treatment has a significant negative impact on quality of life.Cell cycle checkpoint kinase inhibition is a promising method to selectively potentiate the therapeutic effects of chemoradiation. Our hypothesis is that combining chemoradiation with a WEE1 inhibitor will affect the biological response to DNA damage caused by cisplatin and radiation, thereby enhancing clinical outcomes, without increased toxicity. This trial explores the associated effect of WEE1 kinase inhibitor adavosertib (AZD1775). METHODS AND ANALYSIS: This phase I dose-finding, open-label, multicentre trial aims to determine the highest safe dose of AZD1775 in combination with cisplatin chemotherapy preoperatively (group A) as a window of opportunity trial, and in combination with postoperative cisplatin-based chemoradiation (group B).Modified time-to-event continual reassessment method will determine the recommended dose, recruiting up to 21 patients per group. Primary outcomes are recommended doses with predefined target dose-limiting toxicity probabilities of 25% monitored up to 42 days (group A), and 30% monitored up to 12 weeks (group B). Secondary outcomes are disease-free survival times (groups A and B). Exploratory objectives are evaluation of pharmacodynamic (PD) effects, identification and correlation of potential biomarkers with PD markers of DNA damage, determine rate of resection status and surgical complications for group A; and quality of life in group B. ETHICS AND DISSEMINATION: Research Ethics Committee, Edgbaston, West Midlands (REC reference 16/WM/0501) initial approval received on 18/01/2017. Results will be disseminated via peer-reviewed publication and presentation at international conferences. TRIAL REGISTRATION NUMBER: ISRCTN76291951 and NCT03028766.

Optimal identification of human conventional and nonconventional (CRTH2-IL7Rα-) ILC2s using additional surface markers.

BACKGROUND: Human type 2 innate lymphoid cells (ILC2s) are identified by coupled detection of CRTH2 and IL7Rα on lineage negative (Lin-) cells. Type 2 cytokine production by CRTH2-IL7Rα- innate lymphoid cells (ILCs) is unknown. OBJECTIVE: We sought to identify CRTH2-IL7Rα- type 2 cytokine-producing ILCs and their disease relevance. METHODS: We studied human blood and lung ILCs from asthmatic and control subjects by flow cytometry, ELISA, RNA sequencing, quantitative PCR, adoptive transfer to mice, and measurement of airway hyperreactivity by Flexivent. RESULTS: We found that IL-5 and IL-13 were expressed not only by CRTH2+ but also by CRTH2-IL7Rα+ and CRTH2-IL7Rα- (double-negative [DN]) human blood and lung cells. All 3 ILC populations expressed type 2 genes and induced airway hyperreactivity when adoptively transferred to mice. The frequency of type 2 cytokine-positive IL7Rα and DN ILCs were similar to that of CRTH2 ILCs in the blood and lung. Their frequency was higher in asthmatic patients than in disease controls. Transcriptomic analysis of CRTH2, IL7Rα, and DN ILCs confirmed the expression of mRNA for type 2 transcription factors in all 3 populations. Unexpectedly, the mRNA for GATA3 and IL-5 correlated better with mRNA for CD30, TNFR2, ICOS, CCR4, and CD200R1 than for CRTH2. By using a combination of these surface markers, especially CD30/TNFR2, we identified a previously unrecognized ILC2 population. CONCLUSIONS: The commonly used surface markers for human ILC2s leave a majority of type 2 cytokine-producing ILC2s unaccounted for. We identified top GATA3-correlated cell surface-expressed genes in human ILCs by RNA sequencing. These new surface markers, such as CD30 and TNFR2, identified a previously unrecognized human ILC2 population. This ILC2 population is likely to contribute to asthma.

State of the Art in Respiratory Syncytial Virus Drug Discovery and Development.

Respiratory syncytial virus (RSV) is a globally prevalent viral infection with limited treatment options which hospitalizes millions each year. Treatment options have been limited to palivizumab, a monoclonal antibody, approved for prophylaxis in high-risk infants and ribavirin with very limited efficacy and significant safety concerns. This Perspective surveys the range of direct acting antiviral agents (DAAs) that target key steps in the viral life cycle. A number of approaches to DAAs have produced landmark clinical studies over the past few years, notably in fusion and nucleoside inhibitors, and an update of the clinical status of these compounds is provided. Non-nucleoside inhibitors of replication are reviewed in addition to inhibitors of other mechanisms, notably the RSV N and G proteins. This article will provide an informative perspective of the current status of drug discovery targeted at providing an effective therapy for RSV infection.

Durvalumab for recurrent or metastatic head and neck squamous cell carcinoma: Results from a single-arm, phase II study in patients with ≥25% tumour cell PD-L1 expression who have progressed on platinum-based chemotherapy.

BACKGROUND: Patients with recurrent/metastatic head and neck squamous cell carcinoma (R/M HNSCC) progressing on platinum-based chemotherapy have poor prognoses and limited therapeutic options. Programmed cell death-1 (PD-1) and its ligand 1 (PD-L1) are frequently upregulated in HNSCC. The international, multi-institutional, single-arm, phase II HAWK study (NCT02207530) evaluated durvalumab monotherapy, an anti-PD-L1 monoclonal antibody, in PD-L1-high patients with platinum-refractory R/M HNSCC. PATIENTS AND METHODS: Immunotherapy-naïve patients with confirmed PD-L1-high tumour cell expression (defined as patients with ≥25% of tumour cells expressing PD-L1 [TC ≥ 25%] using the VENTANA PD-L1 [SP263] Assay) received durvalumab 10 mg/kg intravenously every 2 weeks for up to 12 months. The primary end-point was objective response rate; secondary end-points included progression-free survival (PFS) and overall survival (OS). RESULTS: Among evaluable patients (n = 111), objective response rate was 16.2% (95% confidence interval [CI], 9.9-24.4); 29.4% (95% CI, 15.1-47.5) for human papillomavirus (HPV)-positive patients and 10.9% (95% CI, 4.5-21.3) for HPV-negative patients. Median PFS and OS for treated patients (n = 112) was 2.1 months (95% CI, 1.9-3.7) and 7.1 months (95% CI, 4.9-9.9); PFS and OS at 12 months were 14.6% (95% CI, 8.5-22.1) and 33.6% (95% CI, 24.8-42.7). Treatment-related adverse events were 57.1% (any grade) and 8.0% (grade ≥3); none led to death. At data cut-off, 24.1% of patients remained on treatment or in follow-up. CONCLUSION: Durvalumab demonstrated antitumour activity with acceptable safety in PD-L1-high patients with R/M HNSCC, supporting its ongoing evaluation in phase III trials in first- and second-line settings. In an ad hoc analysis, HPV-positive patients had a numerically higher response rate and survival than HPV-negative patients.

New insights in the diagnosis of chronic refractory cough.

BACKGROUND: Chronic Refractory Cough (CRC) is a common condition that significantly impairs patients' quality of life. Unfortunately, in many situations patients continue to experience CRC in spite of following published guidelines for diagnosis and treatment. METHODS: 99 patients were referred to National Jewish Health (NJH), a specialty respiratory center for evaluation of CRC (cough ≥ 8 weeks duration). Study duration occurred over 18 months. Intake evaluation for all patients included history, physical examination, spirometry and fiberoptic laryngoscopy. Testing to confirm causes of CRC were performed. Specific therapy for each potential cause was provided. A visual analog cough scale measured cough response. RESULTS: Ten final diagnostic categories were found in the cohort of 99 patients with CRC: Obstructive sleep apnea (apnea/hypoxia index ≥ 5), rhinosinusitis, Tracheobronchomalacia (≥65% collapse of airway with dynamic expiratory imaging), esophageal dysmotility, gastroesophageal reflux, abnormal swallowing with laryngeal penetration, asthma, COPD, bronchiectasis and paradoxical vocal cord movement. In these patients there were 42 incorrect intake diagnoses and 101 new diagnoses established. Patients with CRC have had multiple diagnoses (3.8 ±â€¯1.6) associated with chronic cough. With directed therapy 71/76 (93%) patients had resolution or improvement in cough symptoms. CONCLUSIONS: Among patients referred to a specialty respiratory center with CRC multiple concomitant diagnoses for cough were common. Certain diagnoses such as OSA and TBM have not been reported in cough guidelines but in this study are commonly associated diagnoses. Targeted therapy for each recognized diagnosis improves patient response.

The Clinical Utility of Cell-Free DNA Measurement in Differentiated Thyroid Cancer: A Systematic Review.

BACKGROUND: Cell-free DNA (cfDNA) can be detected in the circulation of healthy individuals, but is found in higher concentrations in cancer patients. Furthermore, mutations in tumor cells can be identified in circulating DNA fragments. This has been the subject of significant interest in the field of cancer research, but little has been published in thyroid cancer. OBJECTIVES: To assess all available evidence on the use of circulating cfDNA in the diagnosis, management and surveillance of patients with differentiated thyroid cancer, and collate it into a systematic review to guide future research. METHODS: A comprehensive literature search on the measurement of cfDNA in thyroid cancer was undertaken, and results from relevant studies collated into a systematic review. RESULTS: Nine studies were identified, with varying methodologies and findings. Key techniques and findings are summarized. CONCLUSION: There is limited but promising evidence that somatic mutations in thyroid cancer can be detected in circulating cfDNA and are associated with more advanced disease. Further research is required to develop a clinically useful tool based on cfDNA to improve the management of thyroid cancers.

Airway and serum biochemical correlates of refractory neutrophilic asthma.

BACKGROUND: Despite progress in the diagnosis and management of asthma, many patients have poorly controlled or refractory asthma (RA). The mechanism of this RA is not well understood. OBJECTIVE: We sought to explore the relationship between neutrophils and other biomarkers of RA. METHOD: Sixty patients with RA, 30 patients with nonrefractory asthma (NRA), and 20 healthy subjects were enrolled. We performed a comprehensive characterization of these study subjects, which included laboratory and pulmonary function studies, chest computed tomography, and bronchoscopy with bronchoalveolar lavage (BAL). We analyzed BAL fluid and serum for a total of 244 biomolecules using a multiplex assay and correlated them with clinical and other laboratory parameters. RESULTS: RA was significantly different from NRA with regard to pulmonary function indices, bronchial basement membrane thickness, and BAL fluid neutrophil and lymphocyte counts but not eosinophil counts. BAL fluid neutrophil counts negatively and positively correlated with forced vital capacity and age, respectively. Of the 244 biomolecules studied, 52 and 14 biomolecules from BAL fluid and serum, respectively, were significantly different among the study groups. Thirteen of these 52 molecules correlated with BAL fluid neutrophil counts. BAL fluid from 40% of patients with RA was positive for a pathogenic microbe. Infection-negative neutrophilic RA was associated with an increase in levels of select biomarkers of inflammation in the serum, suggesting the presence of systemic inflammation. CONCLUSIONS: RA was associated with increased numbers of neutrophils and proneutrophilic biomolecules in the airways. Subclinical infection was present in 40% of patients with RA, which likely contributed to neutrophilic inflammation. A subgroup of patients with noninfected neutrophilic RA was associated with systemic inflammation.

Mechanism of TH2/TH17-predominant and neutrophilic TH2/TH17-low subtypes of asthma.

BACKGROUND: The mechanism of TH2/TH17-predominant and TH2/TH17-low asthma is unknown. OBJECTIVE: We sought to study the immune mechanism of TH2/TH17-predominant and TH2/TH17-low asthma. METHODS: In a previously reported cohort of 60 asthmatic patients, 16 patients were immunophenotyped with TH2/TH17-predominant asthma and 22 patients with TH2/TH17-low asthma. We examined bronchoalveolar lavage (BAL) fluid leukocytes, cytokines, mediators, and epithelial cell function for these asthma subgroups. RESULTS: Patients with TH2/TH17-predominant asthma had increased IL-1ß, IL-6, IL-23, C3a, and serum amyloid A levels in BAL fluid, and these correlated with IL-1ß and C3a levels. TH2/TH17 cells expressed higher levels of the IL-1 receptor and phospho-p38 mitogen-activated protein kinase. Anakinra, an IL-1 receptor antagonist protein, inhibited BAL TH2/TH17 cell counts. TH2/TH17-low asthma had 2 distinct subgroups: neutrophilic asthma (45%) and pauci-inflammatory asthma (55%). This contrasted with patients with TH2/TH17-predominant and TH2-predominant asthma, which included neutrophilic asthma in 6% and 0% of patients, respectively. BAL fluid neutrophils strongly correlated with BAL fluid myeloperoxidase, IL-8, IL-1α, IL-6, granulocyte colony-stimulating factor, and GM-CSF levels. Sixty percent of the patients with neutrophilic asthma had a pathogenic microorganism in BAL culture, which suggested a subclinical infection. CONCLUSION: We uncovered a critical role for the IL-1ß pathway in patients with TH2/TH17-predminant asthma. A subgroup of patients with TH2/TH17-low asthma had neutrophilic asthma and increased BAL fluid IL-1α, IL-6, IL-8, granulocyte colony-stimulating factor, and GM-CSF levels. IL-1α was directly involved in IL-8 production and likely contributed to neutrophilic asthma. Sixty percent of neutrophilic patients had a subclinical infection.

Peptidomimetic Small Molecules Disrupt Type IV Secretion System Activity in Diverse Bacterial Pathogens.

UNLABELLED: Bacteria utilize complex type IV secretion systems (T4SSs) to translocate diverse effector proteins or DNA into target cells. Despite the importance of T4SSs in bacterial pathogenesis, the mechanism by which these translocation machineries deliver cargo across the bacterial envelope remains poorly understood, and very few studies have investigated the use of synthetic molecules to disrupt T4SS-mediated transport. Here, we describe two synthetic small molecules (C10 and KSK85) that disrupt T4SS-dependent processes in multiple bacterial pathogens. Helicobacter pylori exploits a pilus appendage associated with the cag T4SS to inject an oncogenic effector protein (CagA) and peptidoglycan into gastric epithelial cells. In H. pylori, KSK85 impedes biogenesis of the pilus appendage associated with the cag T4SS, while C10 disrupts cag T4SS activity without perturbing pilus assembly. In addition to the effects in H. pylori, we demonstrate that these compounds disrupt interbacterial DNA transfer by conjugative T4SSs in Escherichia coli and impede vir T4SS-mediated DNA delivery by Agrobacterium tumefaciens in a plant model of infection. Of note, C10 effectively disarmed dissemination of a derepressed IncF plasmid into a recipient bacterial population, thus demonstrating the potential of these compounds in mitigating the spread of antibiotic resistance determinants driven by conjugation. To our knowledge, this study is the first report of synthetic small molecules that impair delivery of both effector protein and DNA cargos by diverse T4SSs. IMPORTANCE: Many human and plant pathogens utilize complex nanomachines called type IV secretion systems (T4SSs) to transport proteins and DNA to target cells. In addition to delivery of harmful effector proteins into target cells, T4SSs can disseminate genetic determinants that confer antibiotic resistance among bacterial populations. In this study, we sought to identify compounds that disrupt T4SS-mediated processes. Using the human gastric pathogen H. pylori as a model system, we identified and characterized two small molecules that prevent transfer of an oncogenic effector protein to host cells. We discovered that these small molecules also prevented the spread of antibiotic resistance plasmids in E. coli populations and diminished the transfer of tumor-inducing DNA from the plant pathogen A. tumefaciens to target cells. Thus, these compounds are versatile molecular tools that can be used to study and disarm these important bacterial machines.

Thiazolino 2-Pyridone Amide Inhibitors of Chlamydia trachomatis Infectivity.

The bacterial pathogen Chlamydia trachomatis is a global health burden currently treated with broad-spectrum antibiotics which disrupt commensal bacteria. We recently identified a compound through phenotypic screening that blocked infectivity of this intracellular pathogen without host cell toxicity (compound 1, KSK 120). Herein, we present the optimization of 1 to a class of thiazolino 2-pyridone amides that are highly efficacious (EC50 ≤ 100 nM) in attenuating infectivity across multiple serovars of C. trachomatis without host cell toxicity. The lead compound 21a exhibits reduced lipophilicity versus 1 and did not affect the growth or viability of representative commensal flora at 50 µM. In microscopy studies, a highly active fluorescent analogue 37 localized inside the parasitiphorous inclusion, indicative of a specific targeting of bacterial components. In summary, we present a class of small molecules to enable the development of specific treatments for C. trachomatis.