Macrophages are a heterogeneous population of cells with an important role in innate immunity and tissue regeneration. Based on in vitro experiments, macrophages have been subdivided into five ...distinct subtypes named M1, M2a, M2b, M2c, and M2d, depending on the means of their activation and the cell surface markers they display. Whether all subtypes can be detected in vivo is still unclear. The identification of macrophages in vivo in the regenerating muscle could be used as a new diagnostic tool to monitor therapeutic strategies for tissue repair. The use of classical immunolabeling techniques is unable to discriminate between different M2 macrophages and a functional characterization of these macrophages is lacking. Using in situ hybridization coupled with hybridization‐chain‐reaction detection (HCR), we achieved the identification of M2d‐like macrophages within regenerating muscle and applied this technique to understand the role of M2 macrophages in the regeneration of irradiated pig‐muscle after adipose tissue stem cell treatment. Our work highlights the limits of immunolabeling and the usefulness of HCR analysis to provide valuable information for macrophage characterization.
No study has evaluated the predictive and prognostic role of CD8 and PD-L1 coexpression in non-small-cell lung cancer (NSCLC).
We analyzed RNA sequencing and/or immunohistochemistry staining in NSCLC ...patients from The Cancer Genome Atlas (n = 1016), and 34 metastatic NSCLC samples not treated by immunotherapy as prognostic cohorts. As predictive aspect of CD8 and PD-L1, we used 85 NSCLC patients treated with anti-PD-1. Two validation cohorts were used including 44 NSCLC patients treated with anti-PD-1 and an external cohort with different tumor types.
In prognostic cohorts, high CD8A expression was associated with longer OS (p = 0.02), while high CD274 mRNA was associated with poor prognosis (p = 0.05). In predictive cohort, high CD8 expression and CD8A mRNA were associated with longer progression-free survival (PFS) (p = 0.0002). There was no significant association between PD-L1 expression and PFS while high CD274 mRNA was associated with longer PFS (p = 0.009). A combination of CD8A and CD274 was highly predictive of outcome. These results were confirmed in the validation cohorts. This two-genes signature demonstrated similar results compared to gold standard signatures.
CD8 represents both a prognostic and predictive factor of outcomes, while PD-L1 share different prognostic and predictive roles.
Nivolumab, a monoclonal antibody targeting PD-1, is currently approved for metastatic non-small cell lung cancer (mNSCLC) treatment after failure of first-line chemotherapy. However, only a quarter ...of patients benefit from this therapy with objective clinical response. In this context, there is an unmet need for improved understanding of resistance mechanisms. Thus, we studied a prospective cohort of mNSCLC (n = 61) treated in second or third-line with nivolumab. We analyzed various blood myeloid and lymphoid markers by flow cytometry (176 variables) at baseline, and after 15 and 30 days of therapy. By attempting to link the evolution of peripheral lymphoid, myeloid cells and anti-PD-1 response, we observed that accumulation of lymphoid cells and monocytic MDSC (mMDSC) expressing, respectively, Tim-3 and galectin-9 is implicated in resistance to PD-1 blockade both for patients with primary or acquired secondary resistance to anti-PD-1. In vitro, anti-Tim-3 blocking antibody reverses resistance to anti-PD-1 in PBMC from lung cancer patients and high levels of blood mMDSC negatively impact on anti-PD-1 efficacy. Together, these data underline that the galectin-9/Tim-3 pathway and mMDSC are key mechanisms of primary or secondary resistance to anti-PD-1 and could be a new target for immunotherapy drug combinations.
Over the past 70 years, significant progress has been made in understanding the molecular and cellular mechanisms of inflammation and tissue regeneration ....
Background
Checkpoint inhibitors (CKI) targeting PD-1 or PD-L1 are major therapies for the treatment of non-small cell lung cancer (NSCLC). Despite numerous studies of biological biomarkers, we ...currently lack a marker to predict CKI primary resistance. The aim of this study was to isolate clinical markers associated with the absence of efficacy of CKI used as monotherapy in NSCLC.
Methods
We conducted a retrospective analysis of 172 patients treated with anti-PD1 or anti-PDL1 monoclonal antibodies (mAb) for advanced NSCLC at the Dijon Cancer Center. Baseline characteristics were compared using the Chi squared test between responders and non-responders. Survival curves were estimated by the Kaplan–Meier method and compared with the Log-rank test for univariate analysis. Cox regression models were used to determine hazard ratios and 95% confidence intervals for progression-free survival (PFS) and overall survival (OS).
Results
Among 172 patients included, 149 (86.5%) received CKI after platinum chemotherapy. Response rate (RR) was 16%, median progression-free survival (PFS) was 2.5 months (95% CI 0.7–30 months) and median overall survival (OS) was 10 months (95% CI 0.7–46.8 months). By univariate analysis, WHO performance status ≥ 1, presence of bone, liver and pleuroperitoneal metastasis were associated with poor PFS and OS. Multivariate analysis showed that only pleuroperitoneal metastasis was independently associated with PFS and OS. Patients with pleuroperitoneal metastasis and WHO performance status ≥ 1 had a < 10% chance of yielding a benefit from CKI.
Conclusions
Our data support the hypothesis that pleuroperitoneal metastasis is a major predictive factor affecting CKI efficacy in NSCLC patients and may be used to avoid CKI monotherapy for such patients.
Understanding the processes of inflammation and tissue regeneration after injury is of great importance. For a long time, macrophages have been known to play a central role during different stages of ...inflammation and tissue regeneration. However, the molecular and cellular mechanisms by which they exert their effects are as yet mostly unknown. While in vitro macrophages have been characterized, recent progress in macrophage biology studies revealed that macrophages in vivo exhibited distinctive features. Actually, the precise characterization of the macrophages in vivo is essential to develop new healing treatments and can be approached via in situ analyses. Nowadays, the characterization of macrophages in situ has improved significantly using antigen surface markers and cytokine secretion identification resulting in specific patterns. This review aims for a comprehensive overview of different tools used for in situ macrophage identification, reporter genes, immunolabeling and in situ hybridization, discussing their advantages and limitations.
Producing industrially significant compounds with more environmentally friendly represents a challenging task. The large-scale production of an exogenous molecule in a host microfactory can quickly ...cause toxic effects, forcing the cell to inhibit production to survive. The key point to counter these toxic effects is to promote a gain of tolerance in the host, for instance, by inducing a constant flux of the neo-synthetized compound out of the producing cells. Efflux pumps are membrane proteins that constitute the most powerful mechanism to release molecules out of cells. We propose here a new biological model, Deinococcus geothermalis, organism known for its ability to survive hostile environment; with the aim of coupling the promising industrial potential of this species with that of heterologous efflux pumps to promote engineering tolerance. In this study, clones of D. geothermalis containing various genes encoding chromosomal heterologous efflux pumps were generated. Resistant recombinants were selected using antibiotic susceptibility tests to screen promising candidates. We then developed a method to determine the efflux efficiency of the best candidate, which contains the gene encoding the MdfA of Salmonella enterica serovar Choleraesuis. We observe 1.6 times more compound in the external medium of the hit recombinant than that of the WT at early incubation time. The data presented here will contribute to better understanding of the parameters required for efficient production in D. geothermalis.
Advances in understanding tissue regenerative mechanisms require the characterization of in vivo macrophages as those play a fundamental role in this process. This characterization can be approached ...using the immuno-fluorescence method with widely studied and used pan-markers such as CD206 protein. This work investigated CD206 expression in an irradiated-muscle pig model using three different antibodies. Surprisingly, the expression pattern during immunodetection differed depending on the antibody origin and could give some false results. False results are rarely described in the literature, but this information is essential for scientists who need to characterize macrophages. In this context, we showed that in situ hybridization coupled with hybridization-chain-reaction detection (HCR) is an excellent alternative method to detect macrophages in situ.
Melioidosis is an endemic disease in southeast Asia and northern Australia caused by the saprophytic bacteria Burkholderia pseudomallei, with a high mortality rate. The clinical presentation is ...multifaceted, with symptoms ranging from acute septicemia to multiple chronic abscesses. Here, we report a chronic case of melioidosis in a patient who lived in Malaysia in the 70s and was suspected of contracting tuberculosis. Approximately 40 years later, in 2014, he was diagnosed with pauci-symptomatic melioidosis during a routine examination. Four strains were isolated from a single sample. They showed divergent morphotypes and divergent antibiotic susceptibility, with some strains showing resistance to trimethoprim-sulfamethoxazole and fluoroquinolones. In 2016, clinical samples were still positive for B. pseudomallei, and only one type of strain, showing atypical resistance to meropenem, was isolated.
We performed whole genome sequencing and RT-qPCR analysis on the strains isolated during this study to gain further insights into their differences. We thus identified two types of resistance mechanisms in these clinical strains. The first one was an adaptive and transient mechanism that disappeared during the course of laboratory sub-cultures; the second was a mutation in the efflux pump regulator amrR, associated with the overexpression of the related transporter.
The development of such mechanisms may have a clinical impact on antibiotic treatment. Indeed, their transient nature could lead to an undiagnosed resistance. Efflux overexpression due to mutation leads to an important multiple resistance, reducing the effectiveness of antibiotics during treatment.
Immune checkpoint inhibitors (ICIs) have improved the care of patients in multiple cancer types. However, PD-L1 status, high Tumor Mutational Burden (TMB), and mismatch repair deficiency are the only ...validated biomarkers of efficacy for ICIs. These markers remain imperfect, and new predictive markers represent an unmet medical need. Whole-exome sequencing was carried out on 154 metastatic or locally advanced cancers from different tumor types treated by immunotherapy. Clinical and genomic features were investigated using Cox regression models to explore their capacity to predict progression-free survival (PFS). The cohort was split into training and validation sets to assess validity of observations. Two predictive models were estimated using clinical and exome-derived variables, respectively. Stage at diagnosis, surgery before immunotherapy, number of lines before immunotherapy, pleuroperitoneal, bone or lung metastasis, and immune-related toxicity were selected to generate a clinical score.
mutations, TMB, TCR clonality, and Shannon entropy were retained to generate an exome-derived score. The addition of the exome-derived score improved the prediction of prognosis compared with the clinical score alone. Exome-derived variables could be used to predict responses to ICI independently of tumor type and might be of value in improving patient selection for ICI therapy.
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