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Purpose: Cancer patients are at risk of severe COVID-19 infection, and vaccination is recommended. Nevertheless, we observe a failure of COVID-19 vaccines in this vulnerable population. We hypothesize that senescent peripheral T-cells alter COVID-19 vaccine-induced immunity. Methods: We performed a monocentric prospective study and enrolled cancer patients and healthy donors before the COVID-19 vaccination. The primary objective was to assess the association of peripheral senescent T-cells (CD28-CD57+KLRG1+) with COVID-19 vaccine-induced immunity. Results: Eighty cancer patients have been included, with serological and specific T-cell responses evaluated before and at 3 months post-vaccination. Age ≥ 70 years was the principal clinical factor negatively influencing the serological (p=0.035) and specific SARS-CoV-2 T-cell responses (p=0.047). The presence of senescent T-cells was correlated to lower serological (p=0.049) and specific T-cell responses (p=0.009). Our results sustained the definition of a specific cutoff for senescence immune phenotype (SIP) (≥ 5% of CD4 and ≥ 39.5% of CD8 T-cells), which was correlated to a lower serological response induced by COVID-19 vaccination for CD4 and CD8 SIPhigh (p=0.039 and p=0.049 respectively). While CD4 SIP level had no impact on COVID-19 vaccine efficacy in elderly patients, our results unraveled a possible predictive role for CD4 SIPhigh T-cell levels in younger cancer patients. Conclusions: Elderly cancer patients have a poor serological response to vaccination; specific strategies are needed in this population. Also, the presence of a CD4 SIPhigh affects the serological response in younger patients and seems to be a potential biomarker of no vaccinal response. [ABSTRACT FROM AUTHOR]

Background: Lung cancer is a cancer of the elderly, with a median age at diagnosis of 71. More than one-third of people diagnosed with lung cancer are over 75 years old. Immune checkpoint inhibitors (ICIs) are special antibodies that target a pathway in the immune system called the programmed cell death 1/programmed cell death-ligand 1 (PD-1/PD-L1) pathway. These antibodies help the immune system fight cancer cells by blocking signals that cancer cells use to avoid being attacked by the immune system. ICIs have changed the treatment of people with lung cancer. In particular, for people with previously-untreated advanced non-small cell lung cancer (NSCLC), current first-line treatment now comprises ICIs plus platinum-based chemotherapy, rather than platinum-based chemotherapy alone, regardless of their PD-L1 expression status. However, as people age, their immune system changes, becoming less effective in its T cell responses. This raises questions about how well ICIs work in older adults., Objectives: To assess the effects of immune checkpoint inhibitors (ICIs) in combination with platinum-based chemotherapy compared to platinum-based chemotherapy (with or without bevacizumab) in treatment-naïve adults aged 65 years and older with advanced NSCLC., Search Methods: We searched the Cochrane Lung Cancer Group Trial Register, CENTRAL, MEDLINE, Embase, two other trial registers, and the websites of drug regulators. The latest search date was 23 August 2023. We also checked references and searched abstracts from the meetings of seven cancer organisations from 2019 to August 2023., Selection Criteria: We included randomised controlled trials (RCTs) that reported on the efficacy and safety of adding ICIs to platinum-based chemotherapy compared to platinum-based chemotherapy alone for people 65 years and older who had not previously been treated. All data emanated from international multicentre studies involving adults with histologically-confirmed advanced NSCLC who had not received any previous systemic anticancer therapy for their advanced disease., Data Collection and Analysis: We used standard methodological procedures expected by Cochrane. Our primary outcomes were overall survival and treatment-related adverse events (grade 3 or higher). Our secondary outcomes were progression-free survival, objective response rate, time to response, duration of response, and health-related quality of life (HRQoL)., Main Results: We included 17 primary studies, with a total of 4276 participants, in the review synthesis. We identified nine ongoing studies, and listed one study as 'awaiting classification'. Twelve of the 17 studies included people older than 75 years, accounting for 9% to 13% of their participants. We rated some studies as having 'some concerns' for risk of bias arising from the randomisation process, deviations from the intended interventions, or measurement of the outcome. The overall GRADE rating for the certainty of the evidence ranged from moderate to low because of the risk of bias, imprecision, or inconsistency. People aged 65 years and older The addition of ICIs to platinum-based chemotherapy probably increased overall survival compared to platinum-based chemotherapy alone (hazard ratio (HR) 0.78, 95% confidence interval (CI) 0.70 to 0.88; 8 studies, 2093 participants; moderate-certainty evidence). Only one study reported data for treatment-related adverse events (grade 3 or higher). The frequency of treatment-related adverse events may not differ between the two treatment groups (risk ratio (RR) 1.09, 95% CI 0.89 to 1.32; 1 study, 127 participants; low-certainty evidence). The addition of ICIs to platinum-based chemotherapy probably improves progression-free survival (HR 0.61, 95% CI 0.54 to 0.68; 7 studies, 1885 participants; moderate-certainty evidence). People aged 65 to 75 years, inclusive The addition of ICIs to platinum-based chemotherapy probably improved overall survival compared to platinum-based chemotherapy alone (HR 0.75, 95% CI 0.65 to 0.87; 6 studies, 1406 participants; moderate-certainty evidence). Only one study reported data for treatment-related adverse events (grade 3 or higher). The frequency of treatment-related adverse events probably increased in people treated with ICIs plus platinum-based chemotherapy compared to those treated with platinum-based chemotherapy alone (RR 1.47, 95% CI 1.02 to 2.13; 1 study, 97 participants; moderate-certainty evidence). The addition of ICIs to platinum-based chemotherapy probably improved progression-free survival (HR 0.64, 95% CI 0.57 to 0.73; 8 studies, 1466 participants; moderate-certainty evidence). People aged 75 years and older There may be no difference in overall survival in people treated with ICIs combined with platinum-based chemotherapy compared to platinum-based chemotherapy alone (HR 0.90, 95% CI 0.70 to 1.16; 4 studies, 297 participants; low-certainty evidence). No data on treatment-related adverse events were available in this age group. The effect of combination ICI and platinum-based chemotherapy on progression-free survival is uncertain (HR 0.83, 95% CI 0.51 to 1.36; 3 studies, 226 participants; very low-certainty evidence). Only three studies assessed the objective response rate. For time to response, duration of response, and health-related quality of life, we do not have any evidence yet., Authors' Conclusions: Compared to platinum-based chemotherapy alone, adding ICIs to platinum-based chemotherapy probably leads to higher overall survival and progression-free survival, without an increase in treatment-related adverse events (grade 3 or higher), in people 65 years and older with advanced NSCLC. These data are based on results from studies dominated by participants between 65 and 75 years old. However, the analysis also suggests that the improvements reported in overall survival and progression-free survival may not be seen in people older than 75 years., (Copyright © 2024 The Cochrane Collaboration. Published by John Wiley & Sons, Ltd.)

Objectives: This is a protocol for a Cochrane Review (intervention). The objectives are as follows: To evaluate the effectiveness and safety of immune checkpoint inhibitors (ICI) as monotherapy or in combination compared to standard of care for elderly people (≥ 65 years) with non-small cell lung cancer (NSCLC)., (Copyright © 2024 The Cochrane Collaboration. Published by John Wiley & Sons, Ltd.)

Background: New strategies in immunotherapy with specific antigens that trigger an anti-tumour immune response in people with lung cancer open the possibility of developing therapeutic vaccines aimed at boosting the adaptive immune response against cancer cells., Objectives: To evaluate the effectiveness and safety of different types of therapeutic vaccines for people with advanced non-small cell lung cancer., Search Methods: We searched CENTRAL, MEDLINE, Embase, Wanfang Data, and China Journal Net (CNKI) up to 22 August 2023., Selection Criteria: We included parallel-group, randomised controlled trials evaluating a therapeutic cancer vaccine, alone or in combination with other treatments, in adults (> 18 years) with advanced non-small cell lung cancer (NSCLC), whatever the line of treatment., Data Collection and Analysis: We used standard methodological procedures expected by Cochrane. Our primary outcomes were overall survival, progression-free survival, and serious adverse events; secondary outcomes were three- and five-year survival rates and health-related quality of life., Main Results: We included 10 studies with 2177 participants. The outcome analyses included only 2045 participants (1401 men and 644 women). The certainty of the evidence varied by vaccine and outcome, and ranged from moderate to very low. We report only the results for primary outcomes here. TG4010 The addition of the vector-based vaccine, TG4010, to chemotherapy, compared with chemotherapy alone in first-line treatment, may result in little to no difference in overall survival (hazard ratio (HR) 0.83, 95% confidence interval (CI) 0.65 to 1.05; 2 studies, 370 participants; low-certainty evidence). It may increase progression-free survival slightly (HR 0.74, 95% CI 0.55 to 0.99; 1 study, 222 participants; low-certainty evidence). It may result in little to no difference in the proportion of participants with at least one serious treatment-related adverse event, but the evidence is very uncertain (risk ratio (RR) 0.70, 95% CI 0.23 to 2.19; 2 studies, 362 participants; very low-certainty evidence). Epidermal growth factor vaccine Epidermal growth factor vaccine, compared to best supportive care as switch maintenance treatment after first-line chemotherapy, may result in little to no difference in overall survival (HR 0.82, 95% CI 0.66 to 1.02; 1 study, 378 participants; low-certainty evidence), and in the proportion of participants with at least one serious treatment-related adverse event (RR 1.32, 95% CI 0.88 to 1.98; 2 studies, 458 participants; low-certainty evidence). hTERT (vx-001) The hTERT (vx-001) vaccine compared to placebo as maintenance treatment after first-line chemotherapy may result in little to no difference in overall survival (HR 0.97, 95% CI 0.70 to 1.34; 1 study, 190 participants). Racotumomab Racotumomab compared to placebo as a switch maintenance treatment post-chemotherapy was assessed in one study with 176 participants. It may increase overall survival (HR 0.63, 95% CI 0.46 to 0.87). It may make little to no difference in progression-free survival (HR 0.73, 95% CI 0.53 to 1.00) and in the proportion of people with at least one serious treatment-related adverse event (RR 1.03, 95% CI 0.15 to 7.18). Racotumomab versus docetaxel as switch maintenance therapy post-chemotherapy was assessed in one study with 145 participants. The study did not report hazard rates on overall survival or progression-free survival time, but the difference in median survival times was very small - less than one month. Racotumomab may result in little to no difference in the proportion of people with at least one serious treatment-related adverse event compared with docetaxel (RR 0.89, 95% CI 0.44 to 1.83). Personalised peptide vaccine Personalised peptide vaccine plus docetaxel compared to docetaxel plus placebo post-chemotherapy treatment may result in little to no difference in overall survival (HR 0.80, 95% CI 0.42 to 1.52) and progression-free survival (HR 0.78, 95% CI 0.43 to 1.42). OSE2101 The OSE2101 vaccine compared with chemotherapy, after chemotherapy or immunotherapy, was assessed in one study with 219 participants. It may result in little to no difference in overall survival (HR 0.86, 95% CI 0.62 to 1.19). It may result in a small difference in the proportion of people with at least one serious treatment-related adverse event (RR 0.95, 95% CI 0.91 to 0.99). SRL172 The SRL172 vaccine of killed Mycobacterium vaccae, added to chemotherapy, compared to chemotherapy alone, may result in no difference in overall survival, and may increase the proportion of people with at least one serious treatment-related adverse event (RR 2.07, 95% CI 1.76 to 2.43; 351 participants)., Authors' Conclusions: Adding a vaccine resulted in no differences in overall survival, except for racotumomab, which showed some improvement compared to placebo, but the difference in median survival time was very small (1.4 months) and the study only included 176 participants. Regarding progression-free survival, we observed no differences between the compared treatments, except for TG4010, which may increase progression-free survival slightly. There were no differences between the compared treatments in serious treatment-related adverse events, except for SRL172 (killed Mycobacterium vaccae) added to chemotherapy, which was associated with an increase in the proportion of participants with at least one serious treatment-related adverse event, and OSE2101, which may decrease slightly the proportion of people having at least one serious treatment-related adverse event. These conclusions should be interpreted cautiously, as the very low- to moderate-certainty evidence prevents drawing solid conclusions: many vaccines were evaluated in a single study with small numbers of participants and events., (Copyright © 2024 The Cochrane Collaboration. Published by John Wiley & Sons, Ltd.)

Objective: Vaccinated patients with cancer in follow-up studies showed a high seropositivity rate but impaired antibody titres and T cell responses following mRNA vaccine against COVID-19. Besides clinical characteristics and the type of anticancer treatment before vaccination, the identification of patients susceptible to non-response following vaccination using immunological markers is worth to be investigated., Methods and Analysis: All patients (n=138, solid cancers) were included in the CACOV-VAC Study comprising three cohorts ((neo)-adjuvant, metastatic and surveillance). Immune responses were assessed using, respectively, anti-receptor-binding domain (RBD) SARS-CoV-S-IgG assay and interferon-γ ELISpot assay 3 months following the prime vaccination dose. Immunophenotyping of T cells and immunosuppressive cells from peripheral blood was performed before the prime dose. The serological threshold 3563 AU/mL was used to discriminate non-responders or suboptimal responders versus responders., Results: Most patients achieved seroconversion after receiving the two doses of vaccine (97.6%). The median serological level of anti-RBD SARS-CoV-S-IgG was equal to 3029 for patients at the metastatic stage. The patient's age was the main demographic characteristic that influenced vaccine efficacy. Among the immunological parameters measured at baseline, lower TIGIT (T cell immunoreceptor with Ig and ITIM domains) expression on CD8 T cells was associated with a better vaccine immunogenicity both in terms of humoral and cellular immune responses., Conclusion: Despite a high seroconversion rate, median serological levels of patients with cancer, particularly elderly patients, were below the threshold equal to 3563 AU/mL considered as a humoral correlate of protection against SARS-CoV-2. Our findings suggest that the inhibitory receptor TIGIT might be an interesting predictive biomarker of COVID-19 vaccine immunogenicity and beyond in an anticancer vaccine context., Trial Registration Number: ClinicalTrials.gov Registry (NCT04836793)., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2023. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Purpose: Universal cancer peptide-based vaccine (UCPVax) is a therapeutic vaccine composed of two highly selected helper peptides to induce CD4+ T helper-1 response directed against telomerase. This phase Ib/IIa trial was designed to test the safety, immunogenicity, and efficacy of a three-dose schedule in patients with metastatic non-small-cell lung cancer (NSCLC)., Patients and Methods: Patients with refractory NSCLC were assigned to receive three vaccination doses of UCPVax (0.25 mg, 0.5 mg, and 1 mg) using a Bayesian-based phase Ib followed by phase IIa de-escalating design. The primary end points were dose-limiting toxicity and immune response after three first doses of vaccine. Secondary end points were overall survival (OS) and progression-free survival at 1 year., Results: A total of 59 patients received UCPVax; 95% had three prior lines of systemic therapy. No dose-limiting toxicity was observed in 15 patients treated in phase Ib. The maximum tolerated dose was 1 mg. Fifty-one patients were eligible for phase IIa. The third and sixth dose of UCPVax induced specific CD4+ T helper 1 response in 56% and 87.2% of patients, respectively, with no difference between three dose levels. Twenty-one (39%) patients achieved disease control (stable disease, n = 20; complete response, n = 1). The 1-year OS was 34.1% (95% CI, 23.1 to 50.4), and the median OS was 9.7 months, with no significant difference between dose levels. The 1-year progression-free survival and the median OS were 17.2% (95% CI, 7.8 to 38.3) and 11.6 months (95% CI, 9.7 to 16.7) in immune responders ( P = .015) and 4.5% (95% CI, 0.7 to 30.8) and 5.6 months (95% CI, 2.5 to 10) in nonresponders ( P = .005), respectively., Conclusion: UCPVax was highly immunogenic and safe and provide interesting 1-year OS rate in heavily pretreated advanced NSCLC.

The marine pathogen Vibrio vulnificus senses and responds to environmental stimuli via two chemosensory systems and 42-53 chemoreceptors. Here, we present an analysis of the V. vulnificus Aer2 chemoreceptor, VvAer2, which is the first V. vulnificus chemoreceptor to be characterized. VvAer2 is related to the Aer2 receptors of other gammaproteobacteria, but uncharacteristically contains three PAS domains (PAS1-3), rather than one or two. Using an E. coli chemotaxis hijack assay, we determined that VvAer2, like other Aer2 receptors, senses and responds to O 2 . All three VvAer2 PAS domains bound pentacoordinate b-type heme and exhibited similar O 2 affinities. PAS2 and PAS3 both stabilized O 2 via conserved Iβ-Trp residues, but PAS1, which was easily oxidized in vitro, was unaffected by Iβ-Trp replacement. Our results support a model in which PAS1 is largely dispensable for O 2 -mediated signaling, whereas PAS2 modulates PAS3 signaling, and PAS3 signals to the downstream domains. Each PAS domain appeared to be positionally optimized, because PAS swapping caused altered signaling properties, and neither PAS1 nor PAS2 could replace PAS3. Our findings strengthen previous conclusions that Aer2 receptors are O 2 sensors, but with distinct N-terminal domain arrangements that facilitate, modulate and tune responses based on environmental signals., (© 2022 The Authors. Molecular Microbiology published by John Wiley & Sons Ltd.)

The Aer2 chemoreceptor from Pseudomonas aeruginosa is an O 2 sensor involved in stress responses, virulence, and tuning the behavior of the chemotaxis (Che) system. Aer2 is the sole receptor of the Che2 system. It is soluble, but membrane associated, and forms complexes at the cell pole during stationary phase. The domain arrangement of Aer2 is unusual, with a PAS sensing domain sandwiched between five HAMP domains, followed by a C-terminal kinase-control output domain. The first three HAMP domains form a poly-HAMP chain N-terminal to the PAS sensing domain. HAMP domains are often located between signal input and output domains, where they transduce signals. Given that HAMP1 to 3 reside N-terminal to the input-output pathway, we undertook a systematic examination of their function in Aer2. We found that HAMP1 to 3 influence PAS signaling over a considerable distance, as the majority of HAMP1, 2 and 3 mutations, and deletions of helical phase stutters, led to nonresponsive signal-off or off-biased receptors. PAS signal-on lesions that mimic activated Aer2 also failed to override N-terminal HAMP signal-off replacements. This indicates that HAMP1 to 3 are critical coupling partners for PAS signaling and likely function as a cohesive unit and moveable scaffold to correctly orient and poise PAS dimers for O 2 -mediated signaling in Aer2. HAMP1 additionally controlled the clustering and polar localization of Aer2 in P. aeruginosa. Localization was not driven by HAMP1 charge, and HAMP1 signal-off mutants still localized. Employing HAMP as a clustering and localization determinant, as well as a facilitator of PAS signaling, are newly recognized roles for HAMP domains. IMPORTANCE P. aeruginosa is an opportunistic pathogen that interprets environmental stimuli via 26 chemoreceptors that signal through 4 distinct chemosensory systems. The second chemosensory system, Che2, contains a receptor named Aer2 that senses O 2 and mediates stress responses and virulence and tunes chemotactic behavior. Aer2 is membrane associated, but soluble, and has three N-terminal HAMP domains (HAMP1 to 3) that reside outside the signal input-output pathway of Aer2. In this study, we determined that HAMP1 to 3 facilitate O 2 -dependent signaling from the PAS sensing domain and that HAMP1 controls the formation of Aer2-containing polar foci in P. aeruginosa. Both of these are newly recognized roles for HAMP domains that may be applicable to other non-signal-transducing HAMP domains and poly-HAMP chains.

In this study, we provide the first characterization of a chemoreceptor from Leptospira interrogans, the cause of leptospirosis. This receptor is related to the Aer2 receptors that have been studied in other bacteria. In those organisms, Aer2 is a soluble receptor with one or two PAS-heme domains and signals in response to O 2 binding. In contrast, L. interrogans Aer2 ( Li Aer2) is an unusual membrane-bound Aer2 with a periplasmic domain and three cytoplasmic PAS-heme domains. Each of the three PAS domains bound b -type heme via conserved Eη-His residues. They also bound O 2 and CO with similar affinities to each other and other PAS-heme domains. However, all three PAS domains were uniquely hexacoordinate in the deoxy-heme state, whereas other Aer2-PAS domains are pentacoordinate. Similar to other Aer2 receptors, Li Aer2 could hijack the E. coli chemotaxis pathway but only when it was expressed with an E. coli high-abundance chemoreceptor. Unexpectedly, the response was inverted relative to classic Aer2 receptors. That is, Li Aer2 caused E. coli to tumble (it was signal-on) in the absence of O 2 and to stop tumbling in its presence. Thus, an endogenous ligand in the deoxy-heme state was correlated with signal-on Li Aer2, and its displacement for gas-binding turned signaling off. This response also occurred in a soluble version of Li Aer2 lacking the periplasmic domain, transmembrane (TM) region, and first two PAS domains, meaning that PAS3 alone was sufficient for O 2 -mediated control. Future studies are needed to understand the unique signaling mechanisms of this unusual Aer2 receptor. IMPORTANCE Leptospira interrogans, the cause of the zoonotic infection leptospirosis, is found in soil and water contaminated with animal urine. L. interrogans survives in complex environments with the aid of 12 chemoreceptors, none of which has been explicitly studied. In this study, we characterized the first L. interrogans chemoreceptor, Li Aer2, and reported its unique characteristics. Li Aer2 is membrane-bound, has three cytoplasmic PAS-heme domains that each bound hexacoordinate b -type heme and O 2 turned Li Aer2 signaling off. An endogenous ligand in the deoxy-heme state was correlated with signal-on Li Aer2 and its displacement for O 2 -binding turned signaling off. Our study corroborated previous findings that Aer2 receptors are O 2 sensors, but also demonstrated that they do not all function the same way.

Background: Studies have reported a beneficial role of the addition of trastuzumab to platin-5-FU based chemotherapy in first-line advanced HER2 positive gastroesophageal adenocarcinoma (GEA). However, the effect of taxanes combined with platin-5FU + trastuzumab (PFT) is understudied., Methods: We performed a retrospective cohort study to evaluate the interest of taxanes among HER2-positive advanced GEA patients treated with PFT. We enrolled HER2-positive advanced GEA patients who underwent treatment between January 2009 to March 2021 in seven hospitals centers in France, treated with PFT alone (S group) or with taxanes + PFT regimen (T group). The primary outcome was progression-free survival (PFS). Also, overall survival (OS), response rate, conversion surgery rate, and safety were evaluated., Results: Overall, 65 patients received PFT-based therapy, 24 patients in the T group, and 41 patients in the S group. To avoid the selection bias, only those patients presenting an ECOG-PS of 0-1 and synchronous metastasis (21 patients in the T group and 19 patients in the S group) were included for analysis. The median PFS was 9.3 months (95%CI 7.0 to 17.2) in the T group and 5.9 months (95%CI 3.7 to 9.6) in the S group (log-rank p=0.038). Treatment by taxanes was significantly associated with a better PFS in univariate (HR 0.49; 95%CI 0.25 to 0.98, p=0.042) and multivariate Cox regression analysis (HR 0.44; 95%CI 0.21 to 0.94, p=0.033), and IPTW method (HR 0.56; 95% CI 0.34 to 0.91, p=0.019). OS was prolonged (19.0 months (95%CI 7.8 to 45.2) vs 13.0 months (95%CI 5.5 to 14.8), log-rank p=0.033) in favor of the T group. Treatment by taxanes was significantly associated with a better OS in univariate Cox regression analysis (HR 0.49; 95%CI 0.21 to 0.96, p=0.038) and IPTW method (HR 0.49; 95% CI 0.29 to 0.84, p=0.009). The response rate was higher in the T group, with conversion surgery in five patients. No treatment-related death was observed in both groups., Conclusions: Given the improvement in PFS and OS, the addition of taxanes to standard chemotherapy could be considered as a promising treatment for selected HER2-positive advanced GEA patients, with PS 0-1 and synchronous metastasis (NCT04920747)., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Orillard, Henriques, Vernerey, Almotlak, Calcagno, Fein, Fratté, Jary, Klajer, Vienot, Borg and Kim.)

Background: Cabazitaxel was shown to improve overall survival (OS) in patients with metastatic castration-resistant prostate cancer (mCRPC) after abiraterone/enzalutamine and docetaxel failure, though benefit by the presence of DNA damage repair (DDR) defects is unknown. With the advent of poly(adenosine diphosphate-ribose) polymerase inhibitors (PARPi) in partially overlapping indications with cabazitaxel, we aimed to determine cabazitaxel activity in men with mCRPC according to their DDR status., Methods: This is a retrospective multicenter study that enrolled patients with mCRPC treated with cabazitaxel who had undergone DDR tumour tissue profiling. Patients with at least one deleterious germline or somatic alterations were considered DDR positive (DDR+). Each DDR + patient has been matched with a DDR negative (DDR-) from the same institution who underwent the same test. An exploratory cohort of patients found to be DDR + by liquid biopsy was also included. Prostate specific antigen (PSA) decline≥50% (PSA50), PSA progression-free survival (PFS, PSA-PFS), radiographic PFS (rPFS), clinical PFS or radiographic PFS (c/rPFS) and OS were evaluated., Results: Among 190 men (95 DDR+, 95 DDR-) with tissue sequencing, PSA50 was achieved with cabazitaxel in 29/92 (32%) and 33/92 (36%) in patients with DDR+ and DDR- (P = 0.64). The median rPFS was 5.33 months [95%CI 4.34-7.04] versus 5.75 months [95%CI 4.67-7.27] (P = 0.55). The median OS was 15.4 months [95%CI 12.16-26.6] and 11.5 months [95%CI 9.76-14.4] (P = 0.036), respectively. No PSA50 responses on cabazitaxel were observed in BRCA1/2 patients previously treated with PARPi (n = 10). Similar outcomes with cabazitaxel were observed in the liquid biopsy cohort (n = 63 DDR+)., Conclusions: Our study suggests that cabazitaxel is active in patients with mCRPC regardless of their DDR status, although its activity in men pretreated with a PARPi may be lower., Competing Interests: Conflict of interest statement The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Mihaela Aldea – nothing to disclose. Laurent Lam – nothing to disclose. Emeline Orillard - Honoraria: Astellas, Janssen; Travel, Accommodations, Expenses: Pfizer, Amgen. Casilda Llacer Perez - Travel, Accommodations, Expenses: Astellas Pharma, Angelini Pharma. Mathilde Saint-Ghislain – nothing to disclose. Gwenaelle Gravis - Honoraria (Institution) - Pfizer, BMS, MSD, AstraZeneca, Astellas, Janssen, Bayer; Advisory, Consultancy – BMS, Pfizer, AstraZeneca, Janssen, Sanofi, Ipsen, Bayer; Travel, Accommodations, Expenses: BMS, Pfizer, AstraZeneca, Janssen, Sanofi, Ipsen, MSD. Aude Flechon - Honoraria and Travel, Accommodations, Expenses: AZ Sanofi, Astellas, Janssen AAA. Guilhem Roubaud – Honoraria, travel and advisory: Astellas, Sanofi, Janssen, Astra Zeneca, Ipsen, Pfizer Philippe Barthelemy – Honoraria: Astellas; Advisory, Consultancy: Janssen-Cilag, Sanofi, MSD, BMS, Pfizer, Novartis, Ipsen, Roche; Travel, Accommodations, Expenses: BMS, Amgen, Pfizer, Janssen-Cilag, Roche, Ipsen. Francesco Ricci – nothing to disclose. Frank Priou – nothing to disclose. Zoe Neviere – nothing to disclose. Mathilde Beaufils – nothing to disclose. Brigitte Laguerre – Honoraria and Travel, Accommodations, Expenses: SANOFI, ASTELLAS, BMS, AstraZeneca, Pfizer, JANSSEN. Anne Claire Hardy – Advisory Board: Roche, AstraZeneca, Pfizer, Novartis, GSK, Clovis, Seagen. Carole Helissey - Advisory board: Sanofi, Janssen, Astellas, Roche, Astra Zeneca. Raffaele Ratta – Consulting/Advisory board: AstraZeneca, Astellas, Pfizer, MSD, Bristol-Myers Squibb; Travel, Accommodations, Expenses: Pfizer, Ipsen, Astellas. Delphine Borchiellini - Principal/sub-Investigator of Clinical Trials for: Astellas, AstraZeneca, BMS, Exelixis, Infinity, Janssen, MSD, Novartis, Pfizer, Roche. Honoraria or Advisory/Consultancy: Astellas, AstraZeneca, BMS, Ipsen, MSD, Novartis, Pfizer, Sanofi. Travel, Accommodations, Expenses: BMS, Ipsen, Janssen, Roche. Cedric Pobel – Travel accommodations/Expenses from Amgen and Sandoz. Florence Joly - Expert Board and/or Lectures: Pfizer, GSK, AstraZeneca, Roche, Janssen, Astellas, IPSEN, MSD, BMS, Clovis, Sanofi Bayer. Elena Castro – Consulting/Advisory board: AstraZeneca, Astellas, Bayer, Janssen; Honoraria: Astellas, AstraZeneca, Bayer, Clovis, Janssen, MSD, Pfizer; Research funding (institution): AstraZeneca, Bayer, Janssen; Travel, Accommodations, Expenses: AstraZeneca, Bayer, Janssen. Antoine Thiery-Vuillemin – Honoraria: Pfizer, AstraZeneca, Sanofi, Janssen, Novartis, Ipsen, Roche/Genentech, Bristol-Myers Squibb, MSD, Astellas Pharma; Consulting/Advisory board: Pfizer, AstraZeneca, Sanofi, Janssen, Novartis, Ipsen, Roche, Bristol-Myers Squibb, MSD, Astellas Pharma; Research funding (institution): Pfizer; Travel, Accommodations, Expenses: Roche, MSD, Janssen, Bristol-Myers Squibb. Giulia Baciarello – Honoraria: Janssen, Roche; Consulting or Advisory Role: Amgen, Astellas Oncology, Janssen, Roche; Travel, Accommodations, Expenses: Astellas Oncology, Ipsen, Janssen, Roche. Karim Fizazi - Honoraria - Astellas Pharma, Bayer, Janssen, Sanofi; Consulting or Advisory Role - Amgen (Inst), Astellas Pharma, AstraZeneca (Inst), Bayer, Curevac (Inst), ESSA (Inst), Janssen Oncology, Orion Pharma GmbH, Sanofi; Travel, Accommodations, Expenses – Amgen, Janssen., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

The Aer2 receptor from Pseudomonas aeruginosa has an O 2 -binding PAS-heme domain that stabilizes O 2 via a Trp residue in the distal heme pocket. Trp rotates ∼90° to bond with the ligand and initiate signaling. Although the isolated PAS domain is monomeric, both in solution and in a cyanide-bound crystal structure, an unliganded structure forms a dimer. An overlay of the two structures suggests possible signaling motions but also predicts implausible clashes at the dimer interface when the ligand is bound. Moreover, in a full-length Aer2 dimer, PAS is sandwiched between multiple N- and C-terminal HAMP domains, which would feasibly restrict PAS motions. To explore the PAS dimer interface and signal-induced motions in full-length Aer2, we introduced Cys substitutions and used thiol-reactive probes to examine in vivo accessibility and residue proximities under both aerobic and anaerobic conditions. In vivo, PAS dimers were retained in full-length Aer2 in the presence and absence of O 2 , and the dimer interface was consistent with the isolated PAS dimer structure. O 2 -mediated changes were also consistent with structural predictions in which the PAS N-terminal caps move apart and the C-terminal DxT region moves closer together. The DxT motif links PAS to the C-terminal HAMP domains and was critical for PAS-HAMP signaling. Removing the N-terminal HAMP domains altered the distal PAS dimer interface and prevented signaling, even after signal-on lesions were introduced into PAS. The N-terminal HAMP domains thus facilitate the O 2 -dependent shift of PAS to the signal-on conformation, clarifying their role upstream of the PAS-sensing domain.

Pseudomonas aeruginosa is an opportunistic pathogen that senses and responds to its environment via four chemosensory systems. Oxygen activates the Che2 chemosensory system by binding to the PAS-heme domain of the Aer2 receptor. Ostensibly, the output of Che2 occurs via its response regulator CheY2, but controversy persists over CheY2's exact role. In this study, we show that CheY2 does not interact with the flagellar motor and that the Che2 system does not transfer phosphoryl groups to the chemotaxis (Che) system. We show that CheY2 instead provides feedback control of Aer2 adaptation. In the presence of O 2 , Aer2 signaling increases the autophosphorylation of the histidine kinase CheA2, followed by CheY2-mediated dephosphorylation. CheY2 does not stably retain phosphate and may not signal the output of the Che2 system. Rather, CheY2 activity enhances the direct interaction of CheY2 with the adaptation protein CheD (a role often facilitated by CheC, which P. aeruginosa lacks). In the absence of O 2 , Aer2 does not signal, and CheY2/CheD interactions attenuate. This frees CheD to augment CheR2-mediated methylation of Aer2, which enhances Aer2 signaling. CheD does not interact with CheR2, but most likely interacts with Aer2 via conserved CheD-binding motifs to make Aer2 a better methylation substrate., (© 2020 John Wiley & Sons Ltd.)

Corticosteroids are among the most prescribed drugs in oncology. The indications range from cancer-related indications for refractory symptoms, anti-cancer effects mainly in hematology, supportive measures for cancer-specific treatments and more recently immune-related adverse events induced by modern immunotherapies. In oncological emergencies, corticosteroids are common first-line treatments because of their rapid effect and wide variety of actions. In the last 5 years, with the advance of immune checkpoint inhibitors, corticosteroids are becoming routinely used to manage immune-related adverse effects. Preclinical studies suggested that corticosteroid-induced immunosuppression might dampen the activity of immunotherapies. Prospective clinical studies show that corticosteroid use is a prognostic marker for the cancer outcome in metastatic setting but does not significantly alter the patient's response to immunotherapies per se. Here, we review the state of the art on corticosteroid use in oncology, with a focus on the drugs' potential impact on immunotherapy activity. The comprehensive pharmacological characteristics of corticosteroid drugs, clinical indications, modality of administration and associated precautions for use are discussed in this article., Competing Interests: Conflict of interest statement Mihaela Aldea – nothing to disclose. Emeline Orillard – Honoraria: Astellas Janssen; Travels accommodations: Amgen Pfizer. Laura Mansi – nothing to disclose. Florian Scotte: Vifor pharma, MSD, BMS, Leo Pharma, Pierre Fabre Oncology, Bayer, Pfizer, Amgen, Helsinn, Roche, Tesaro, Mundi Pharma, Mylan, Tilray. Olivier Lambotte – BMS, MSD, Astra Zeneca, Incyte, Janssen, Gilead. Jean-Marie Michot – Principal/sub-Investigator of Clinical Trials for: Amgen, Astex, AstraZeneca, Medimmune, Roche, Sanofi, Xencor. Aurélien Marabelle – Principal/sub-Investigator of Clinical Trials for: Abbvie, Aduro biotech, Agios Pharmaceuticals, Amgen, Argen-X Bvba, Arno Therapeutics, Astex Pharmaceuticals, Astra Aeneca, Astra Zeneca Ab, Aveo, Bayer Healthcare Ag, Bbb Technologies Bv, Beigene, Bioalliance Pharma, Biontech Ag, Blueprint Medicines, Boehringer Ingelheim, Boston Pharmaceuticals, Inc, Bristol Myers Squibb, Bristol-Myers Squibb International Corporation, Ca, Celgene Corporation, Cephalon, Chugai Pharmaceutical Co, Clovis Oncology, Daiichi Sankyo, Debiopharm S.a, Eisai, Eli lilly, Exelixis, Forma, Gamamabs, Genentech, Inc, Gilead Sciences, Inc, Glaxosmithkline, Glenmark Pharmaceuticals, H3 Biomedicine, Inc, Hoffmann La Roche Ag, Incyte Corporation, Innate Pharma, Institut De Recherche Pierre Fabre, Iris Servier, Janssen Cilag, Janssen Research Foundation, Kura Oncology, Kyowa Kirin Pharm. Dev., Inc, Lilly France, Loxo Oncology, Lytix Biopharma As, Medimmune, Menarini Ricerche, Merck Kgaa, Merck Sharp & Dohme Chibret, Merrimack Pharmaceuticals, Merus, Millennium Pharmaceuticals, Nanobiotix, Nektar Therapeutics, Nerviano Medical Sciences, Novartis Pharma, Octimet Oncology Nv, Oncoethix, Oncomed, Oncopeptides, Onyx Therapeutics, Orion Pharma, Oryzon Genomics, Pfizer, Pharma Mar, Pierre Fabre Medicament, Plexxikon, Rigontec Gmbh, Roche, Sanofi Aventis, Sierra Oncology, Taiho Pharma, Tesaro, Tioma Therapeutics, Wyeth Pharmaceuticals France, Xencor, Y's TherapeuticsGustave Roussy Research Grants: Astrazeneca, BMS, Boehringer Ingelheim, Janssen Cilag, Merck, Novartis, Pfizer, Roche, Sanofi. Non-financial support (drug supplied) from Astra Zeneca, Bayer, BMS, Boehringer Ingelheim, Johnson & Johnson, Lilly, Medimmune, Merck serono, NH TherAGuiX, Pfizer, Roche. Member of Clinical Trial Scientific Committee for GSK, Astra Zeneca, Roche. Member of Data Safety and Monitoring Board for Oncovir, Inc. Scientific Advisory Boards for Innate Pharma, Merck Serono, eTheRNA, Lytix pharma, Kyowa Kirin Pharma, Bayer, Novartis, BMS, Symphogen, Genmab, Amgen, Biothera, Nektar, GSK, Oncovir, Pfizer, Seattle Genetics, Roche/Genentech, OSE immunotherapeutics, Transgene, Gritstone, Merck (MSD), Cerenis, Protagen, Partner Therapeutics, Servier, Sanofi, Pierre Fabre, Molecular Partners, IMCheck, Medicxi, Takeda, EISAI, HiFiBio, RedX, J&J, Gilead, Alkermes. Teaching/Speaker Bureau activities: Roche/Genentech, BMS, Merck (MSD), Merck Serono, Astra Zeneca/Medimmune, Amgen, Sanofi. Scientific & Medical Consulting for Roche, Pierre Fabre, Onxeo, EISAI, Bayer, Genticel, Rigontec, Daichii Sankyo, Sanofi, BioNTech, Corvus, GLG, Deerfield, Guidepoint Global, Edimark, System Analytics, imCheck, Sotio, Bioncotech, Molecular Partners, Pillar Partners, Boehringer Ingelheim, T3 Pharma, Servier, Takeda, GI Innovation. Non-Financial Support (travel expenses) from Astra Zeneca, BMS, Merck (MSD), Roche. Co-Founder & Share Holder of PEGASCY SAS (Gustave Roussy Spin Off for Drug Repositioning). Pre-Clinical and Clinical Research Grants (Institutional Funding): Merus, BMS, Boehringer Ingelheim, Transgene, Foundation MSD Avenir. Member of the following scholar societies: European Society for Medical Oncology (ESMO), American Society for Clinical Oncology (ASCO), American Association for Cancer Research (AACR), European Academy for Tumor Immunology (EATI). Founder and president of the French Society for Immunotherapy of Cancer (FITC). Member of the board of the Immuno-Oncology Group at the French Network of Comprehensive Cancer Centers (Unicancer). Member of the working group on rheumatic adverse events induced by cancer immunotherapies of the European League Against Rheumatoid Arthritis (EULAR). Supervisory Board Member of the Gustave Roussy Foundation. Member of the Steering Committee of the Immuno-Oncology Task Force at Unicancer. Member of the editorial boards of the European Journal of Cancer and ESMO IO Tech., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Angiopoietin-2 (ANGPT2) is a prognostic factor in metastatic colorectal cancer (CRC). Nevertheless, it remains to be elucidated which molecular characteristics make up the ANGPT2-related poor-prognosis CRC subset. Public transcriptomic datasets were collected from Gene Expression Omnibus GEO and with the TCGAbiolinks R-package for the TCGA. After appropriate normalization, differential expression analysis was performed using Benjamini and Hochberg method for false discovery rate. Plasma from two prospective clinical trials were used to investigate the clinical impact of ANGPT2-related biomarkers. In the 935 samples included in four annotated platforms (GPL) and derived from localized CRC, ANGPT2 hi expression conferred a worst overall survival (HR = 1.20; p = 0.02). CRC stage, ANGPT2 hi expression but not Consortium Molecular Subtype (CMS) predict overall survival in multivariate analysis. ANGPT2 expression was not correlated with a specific CMS nor to RAS, RAF, MSI, p53, CIN, CIMP genomic alterations. Gene expression analysis revealed that ANGPT2 hi CRC subset is characterized by angiogenesis-related gene expression, presence of myeloid cells, stromal organization and resistance to chemotherapy. A prognostic model was proposed using seric levels of ANGPT2, STC1 and CD138 in 97 mCRC patients. Our results provide evidence that ANGPT2 is a prognostic factor in localized CRC and defined a specific CRC subset with potential clinical implementation., (© 2020 UICC.)

Germ-cell tumors are the most common solid tumors in young men. The follow-up of these patients is very important in their management. In stage I testicular cancer, surveillance is the standard for low-risk disease. In addition to the early detection of relapse, follow-up should be directed towards prevention, detection and treatment of late toxicity, and secondary malignancies. Follow up consists in physical examination, laboratory analysis and radiological imaging. Recently, guidelines recommend risk-adapted surveillance strategy, with a reduction of CT scans numbers, due to the recognition of the risk of ionizing radiation exposure. However, efforts to maintain adequate compliance with follow up are required., (Copyright © 2019. Published by Elsevier Masson SAS.)

Testicular cancers are the most frequent and the most curable cancers in young men. Treatments of these cancers represent a great success with cure rate over to 95 %. However, chemotherapy side effects may occur during or after several years post-treatment. This review aimed to highlight complications and physical and psychological side effects occurring mainly after chemotherapy treatment for testicular cancer, and to propose a personalized post-cancer plan specific for patients treated for testicular cancer. Treatments of these cancers can cause short-term complications (asthenia, nausea, vomiting, alopecia..). These side effects disappear within a few months after the end of the treatments. Late complications may occur several years post-treatment. Cardiovascular disease, metabolic syndrome and secondary neoplasia represent the most severe late effects among patients treated for testicular cancer. Given the increased incidence of these chemotherapy-induced side effects, it is indispensable to establish a specific follow up which must include a particular vigilance on the risk of occurrence of second cancer, a follow-up of the cardio-vascular risk factors, pulmonary and auditory follow-up, and early detection of psychosocial disorders., (Copyright © 2019. Published by Elsevier Masson SAS.)

Purpose: The aim of this study was to determine the prevalence of adherence to adjuvant hormonal therapy (AHT) and to identify risk factors for medication non-adherence in clinical practice in patients with early-stage hormone receptor (HR)-positive breast cancer (BC) previously treated with chemotherapy., Methods: We carried out a cross-sectional, observational, prospective, and multicenter survey based on a structured self-report postal questionnaire (35 items investigating six areas). A sample of 474 patients was drawn from 676 patients potentially eligible. The structured and validated Morisky Medication Adherence Scale-4 items was used for measuring medication adherence. An analysis of risk factors for non-adherence to AHT was performed using a two-step approach: univariate, then multivariate analysis., Results: A total of 280 patients out of the 428 analyzed patients participated in the survey, yielding a response rate of 65.4% [60.9-69.9]. The prevalence of adherence to AHT was estimated at 68.6% [63.1-74.0], corresponding to a high level of adherence. Three risk factors for non-adherence to AHT were identified: > 2 medications to treat comorbidities (p-value = 0.003), age less than 65 years (p-value = 0.008), and patient management in a university hospital setting (p-value = 0.014)., Conclusions: Non-adherence is a common, complex, and multidimensional healthcare problem. This better understanding and knowledge of risk factors will allow healthcare providers (such as oncologists, general practitioners, pharmacists) to more easily identify patients at risk for non-adherence and help them provide appropriate information about AHT and its management, thus improving medication adherence in their patients.

Background: Enterocolitis is a rare, but serious gastrointestinal complication associated with docetaxel-based chemotherapy in patients with cancer. The incidence, clinical presentation and outcome of enterocolitis in patients with cancer treated with docetaxel-based chemotherapy was assessed in this study Patients and Methods: All patients treated with docetaxel for cancer between January 2010 and December 2014 at the University Hospital of Besançon were identified and their medical records reviewed., Results: During this period, 1,227 patients received docetaxel chemotherapy and gastrointestinal events occurred in 381 (31.1%) patients. In multivariate analysis, a higher risk of gastrointestinal events was associated with a higher dose of docetaxel (≥75 mg/m 2 ) (odds ratio(OR)=46.2; 95% confidence interval(CI)=5.4-397.0, p=0.0005) and the first cycle of docetaxel (OR=4.2; 95% CI=1.8-10.1, p=0.001). Among the 381 patients with gastrointestinal events, grade 3/4 neutropenia, diarrhea, febrile neutropenia, mucositis, nausea/vomiting, and rectal bleeding were diagnosed in 65 (17.1%), 51 (13.4%), 37 (9.7%); 12 (3.1%), seven (1.8%) and three (0.8%) patients, respectively; 54 patients (14.2%) were hospitalized. Computed tomographic scan was performed for 39 patients (10.2%). Twenty-seven patients presented radiological signs of enterocolitis. Three deaths (0.8%) related to enterocolitis were recorded. Docetaxel was resumed in 261 patients (68.5%) and the dose was reduced in 89 patients (23.4%). Docetaxel was discontinued in 120 patients (31.5%)., Conclusion: Gastrointestinal events in patients treated with docetaxel may be a potential sign of fatal enterocolitis and require particular attention. Dose reduction at the first cycle may reduce the risk of such events., (Copyright© 2018, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.)

The Aer2 chemoreceptor from Pseudomonas aeruginosa contains a PAS sensing domain that coordinates b -type heme and signals in response to the binding of O 2 , CO, or NO. PAS-heme structures suggest that Aer2 uniquely coordinates heme via a His residue on a 3 10 helix (H234 on Eη), stabilizes O 2 binding via a Trp residue (W283), and signals via both W283 and an adjacent Leu residue (L264). Ligand binding may displace L264 and reorient W283 for hydrogen bonding to the ligand. Here, we clarified the mechanisms by which Aer2-PAS binds heme, regulates ligand binding, and initiates conformational signaling. H234 coordinated heme, but additional hydrophobic residues in the heme cleft were also critical for stable heme binding. O 2 appeared to be the native Aer2 ligand (dissociation constant [ K d ] of 16 μM). With one exception, mutants that bound O 2 could signal, whereas many mutants that bound CO could not. W283 stabilized O 2 binding but not CO binding, and it was required for signal initiation; W283 mutants that could not stabilize O 2 were rapidly oxidized to Fe(III). W283F was the only Trp mutant that bound O 2 with wild-type affinity. The size and nature of residue 264 was important for gas binding and signaling: L264W blocked O 2 binding, L264A and L264G caused O 2 -mediated oxidation, and L264K formed a hexacoordinate heme. Our data suggest that when O 2 binds to Aer2, L264 moves concomitantly with W283 to initiate the conformational signal. The signal then propagates from the PAS domain to regulate the C-terminal HAMP and kinase control domains, ultimately modulating a cellular response. IMPORTANCE Pseudomonas aeruginosa is a ubiquitous environmental bacterium and opportunistic pathogen that infects multiple body sites, including the lungs of cystic fibrosis patients. P. aeruginosa senses and responds to its environment via four chemosensory systems. Three of these systems regulate biofilm formation, twitching motility, and chemotaxis. The role of the fourth system, Che2, is unclear but has been implicated in virulence. The Che2 system contains a chemoreceptor called Aer2, which contains a PAS sensing domain that binds heme and senses oxygen. Here, we show that Aer2 uses unprecedented mechanisms to bind O 2 and initiate signaling. These studies provide both the first functional corroboration of the Aer2-PAS signaling mechanism previously proposed from structure as well as a signaling model for Aer2-PAS receptors., (Copyright © 2017 American Society for Microbiology.)

Axitinib is approved with indication in patients with advanced renal cell carcinoma (RCC). Due to the localization of this cancer, physicians sometimes have to deal with hemodialyzed patients. Data exploring hemodialysis (HD) impact on axitinib pharmacokinetic (PK) or safety are lacking. To date, no data have been published on that problematic. This is the first publication discussing the assessment of axitinib PK for a patient undergoing HD. Our results suggest that there is no influence of HD on axitinib blood concentration. Interestingly, the membranes used are common and represent around 90% of the membranes used in routine for HD. Our data are also reassuring both from activity and from safety perspectives. In that case, axitinib administered at a dose of 6 mg twice a day was well tolerated and allowed 12 months of disease control. These results are in line with previous publications discussing other anti-angiogenic tyrosine kinase inhibitors pharmacokinetics, safety and activity among patients with metastatic RCC undergoing hemodialysis.

Chlamydia is a medically important bacterium that infects eukaryotic cells. Temporal expression of chlamydial genes during the intracellular infection is proposed to be regulated by changes in DNA supercoiling levels. To understand how chlamydial supercoiling levels are regulated, we purified and analyzed three putative Chlamydia trachomatis topoisomerases. As predicted by sequence homology, CT189/190 are the two subunits of DNA gyrase, whereas CT643 is a topoisomerase I. CT660/661 have been predicted to form a second DNA gyrase, but the reconstitute holoenzyme decatenated and relaxed DNA, indicating that the proteins are subunits of topoisomerase IV. Promoter analysis showed that each topoisomerase is transcribed from its own operon by the major chlamydial RNA polymerase. Surprisingly, all three topoisomerase promoters had higher activity from a more supercoiled DNA template. This supercoiling-responsivesness is consistent with negative feedback control of topoisomerase I and topoisomerase IV expression, which is typical of other bacteria. However, activation of the chlamydial gyrase promoter by increased supercoiling is unorthodox compared with the relaxation-induced transcription of gyrase in other bacteria. We present a model in which supercoiling levels during the intracellular chlamydial developmental cycle are regulated by unusual positive feedback control of the gyrase promoter and the temporal expression of three topoisomerases., (© 2015 John Wiley & Sons Ltd.)

Helicobacter pylori is a bacterial pathogen colonizing half of the world's human population. It has been implicated in a number of gastric diseases, from asymptomatic gastritis to cancer. It is characterized by an amazing genetic variability that results from high mutation rates and efficient DNA homologous recombination and transformation systems. Here, we report the characterization of H. pylori RecA (HpRecA), a protein shown to be involved in DNA repair, transformation, and mouse colonization. The biochemical characterization of the purified recombinase reveals activities similar to those of Escherichia coli RecA (EcRecA). We show that in H. pylori, HpRecA is present in about 80,000 copies per cell during exponential growth and decreases to about 50,000 copies in stationary phase. The amount of HpRecA remains unchanged after induction of DNA lesions, suggesting that HpRecA is always expressed at a high level in order to repair DNA damage or facilitate recombination. We performed HpRecA localization analysis by adding a Flag tag to the protein, revealing two different patterns of localization. During exponential growth, RecA-Flag presents a diffuse pattern, overlapping with the DAPI (4',6-diamidino-2-phenylindole) staining of DNA, whereas during stationary phase, the protein is present in more defined areas devoid of DAPI staining. These localizations are not affected by inactivation of competence or DNA recombination genes. Neither UV irradiation nor gamma irradiation modified HpRecA localization, suggesting the existence of a constitutive DNA damage adaptation system.

Helicobacter pylori infects the stomach of about half of the world's human population, frequently causing chronic inflammation at the origin of several gastric pathologies. One of the most remarkable characteristics of the species is its remarkable genomic plasticity in which homologous recombination (HR) plays a critical role. Here, we analyzed the role of the H. pylori homologue of the AddAB recombination protein. Bioinformatics analysis of the proteins unveils the similarities and differences of the H. pylori AddAB complex with respect to the RecBCD and AddAB complexes from Escherichia coli and Bacillus subtilis, respectively. Helicobacter pylori mutants lacking functional addB or/and addA show the same level of sensitivity to DNA-damaging agents such as UV or irradiation and of deficiency in intrachromosomal RecA-dependent HR. Epistasis analyses of both DNA repair and HR phenotypes, using double and triple recombination mutants, demonstrate that, in H. pylori, AddAB and RecOR complexes define two separate presynaptic pathways with little functional overlap. However, neither of these complexes participates in the RecA-dependent process of transformation of these naturally competent bacteria., (© 2010 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.)