Radiation-induced lung fibrosis (RIF) is a delayed side-effect of chest radiotherapy, frequently associated with macrophage infiltration.We aimed to characterise the role of pulmonary macrophages in RIF using human lung biopsies from patients receiving radiotherapy for thorax malignancies and a RIF model developed in C57BL/6 mice after 16-Gy thorax irradiation.High numbers of macrophages (both interstitial and alveolar) were detected in clinical and preclinical RIF. In the preclinical model, upregulation of T-helper (Th)2 cytokines was measured, whereas Th1 cytokines were downregulated in RIF tissue lysate. Bronchoalveolar lavage demonstrated upregulation of both types of cytokines. At steady state, tissue-infiltrating macrophages (IMs) expressed 10-fold more arginase (Arg)-1 than alveolar macrophages (AMs), and a 40-fold upregulation of Arg-1 was found in IMs isolated from RIF. IMs, but not AMs, were able to induce myofibroblast activation In addition, whereas depletion of AMs using Clodrosome didn't affect RIF score, depletion of IMs using a clinically available colony-stimulating factor receptor-1 (CSF1R) neutralising antibody was antifibrotic.These findings suggest differential contributions of alveolar interstitial macrophages in RIF, highlighting the fibrogenic role of IMs. The CSF1/CSF1R pathway was identified as a new therapeutic target to inhibit RIF.

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Purpose: Diffuse intrinsic pontine gliomas (DIPG) are the most severe pediatric brain tumors. Although accepted as the standard therapeutic, radiotherapy is only efficient transiently and not even in every patient. The goal of the study was to identify the underlying molecular determinants of response to radiotherapy in DIPG. Experimental Design: We assessed in vitro response to ionizing radiations in 13 different DIPG cellular models derived from treatment-na€ ve stereotactic biopsies reflecting the genotype variability encountered in patients at diagnosis and correlated it to their principal molecular alterations. Clinical and radiologic response to radiotherapy of a large cohort of 73 DIPG was analyzed according to their genotype. Using a kinome-wide synthetic lethality RNAi screen, we further identified target genes that can sensitize DIPG cells to ionizing radiations. Results: We uncover TP53 mutation as the main driver of increased radioresistance and validated this finding in four isogenic pairs of TP53 WT DIPG cells with or without TP53 knockdown. In an integrated clinical, radiological, and molecular study, we show that TP53 MUT DIPG patients respond less to irradiation, relapse earlier after radiotherapy, and have a worse prognosis than their TP53 WT counterparts. Finally, a kinome-wide synthetic lethality RNAi screen identifies CHK1 as a potential target, whose inhibition increases response to radiation specifically in TP53 MUT cells. Conclusions: Here, we demonstrate that TP53 mutations are driving DIPG radioresistance both in patients and corresponding cellular models. We suggest alternative treatment strategies to mitigate radioresistance with CHK1 inhibitors. These findings will allow to consequently refine radiotherapy schedules in DIPG.

Epidermodysplasia verruciformis (EV) is a rare disease, characterized by cutaneous warts and associated with a strong predisposition to beta-genus human papillomavirus (HPV). Earlier studies reported high copy numbers of HPV-DNA in nearly all skin tumors from EV patients, but neither HPV replication status in non-lesional skin nor anti-HPV seroreactivity in these patients have been reported yet. We therefore performed a comprehensive viral load analysis for the more common beta-HPV types on skin samples and plucked eyebrow hairs from four EV patients treated at our dermatology department. The results clearly demonstrate that they carry a multiplicity (up to eighteen types) of beta-HPV genotypes in both skin sites. Worthy of note, a high intrapatient concordance for specific types between hair bulbs and skin biopsies was observed and the same beta-PV profile was maintained over time. Viral load analysis revealed a load range between less than one HPV-DNA copy per 100 cells to more than 400 HPV-DNA copies per cell in both eyebrow hairs and skin proliferative lesions. Evaluation of seroreactivity to beta-HPV types in the four EV patients revealed that antibodies against the 16 beta-HPV were significantly more prevalent and showed higher titers than in the controls.

Ionizing radiation has historically been used to treat cancer by killing tumour cells, in particular by inducing DNA damage. This view of radiotherapy (RT) as a simple cytotoxic agent has dramatically changed in recent years, and it is now widely accepted that RT can deeply reshape the tumour environment by modulating the immune response. Such evidence gives a strong rationale for the use of immunomodulators to boost the therapeutic value of RT, introducing the era of ‘immunoradiotherapy’. The increasing amount of preclinical and clinical data concerning the combination of RT with immunomodulators, in particular with immune checkpoint inhibitors such as anti‐PD‐1/PD‐L1 and anti‐CTLA4, reflects the interest of the scientific and medical community concerning immunoradiotherapy. The expectations are enormous since the rationale for performing such combinations is strong, with the possibility to use a local treatment such as RT to amplify a systemic antitumour response, as illustrated by the case of the abscopal effect. Nevertheless, several points remain to be addressed such as the need to find biomarkers to identify patients who will benefit from immunoradiotherapy, the identification of the best sequences/schedules for combination with immunomodulators and mechanisms to overcome resistance. Additionally, the effects of immunoradiotherapy on healthy tissues and related toxicity remain largely unexplored. To answer these critical questions and make immunoradiotherapy keep its promising qualities, large efforts are needed from both the pharmaceutical industry and academic/governmental research. Moreover, because of the work of both these entities, the arsenal of available immunomodulators is quickly expanding, thus opening the field to increasing combinations with RT. We thus forecast that the field of immunoradiotherapy will further expand in the coming years, and it needs to be supported by appropriate investment plans.

Objective. To investigate the presence and clinical significance of autoantibodies against the interferoninducible gene IFI16 in systemic sclerosis (SSc), systemic lupus erythematosus (SLE), and other autoimmune diseases.Methods. Immunohistochemical analysis was used to evaluate the expression of IFI16 in skin biopsy specimens obtained from patients with SSc and patients with SLE. Levels of antibodies against IFI16 in sera from 82 patients with SSc and 100 patients with SLE were determined by enzyme-linked immunosorbent assay. Other autoimmune diseases such as primary Sjö-gren's syndrome (SS), rheumatoid arthritis (RA), chronic urticaria, and hepatitis C virus (HCV) infection were also examined.Results. Expression of IFI16 was greatly increased and was ubiquitous in all layers of the epidermis and in the dermal inflammatory infiltrates of lesional skin from both patients with SLE and patients with SSc. Patients with SLE, those with primary SS, and those with SSc exhibited significantly higher anti-IFI16 IgG antibody levels compared with normal controls (for SLE, P < 0.002; for primary SS, P < 0.001; for SSc, P < 0.0005). Anti-IFI16 titers above the ninety-fifth percentile for control subjects were observed in 26% of the patients with SLE, 50% of those with primary SS, and 21% of those with SSc (28% of patients with limited cutaneous SSc [lcSSc] versus 4% of patients with diffuse cutaneous SSc [dcSSc]). In contrast, the prevalence of anti-IFI16 was 4% in patients with RA, 5% in those with chronic urticaria, and 13% in those with HCV infection.Conclusion. The results of this study provide evidence that an IFN-inducible gene, IFI16, may be involved in the pathophysiologic mechanisms of connective tissue disorders such as SSc. Moreover, a strict correlation with lcSSc was also demonstrated, thus providing a novel tool in the differential diagnosis of lcSSc from dcSSc.

The finding that IFI16 is present in the cytoplasm of diseased skin cells from patients with SLE and the demonstration of IFI16 in the supernatants of UVB-exposed keratinocytes, suggest that UVB irradiation or other stimuli may favour an abnormal IFI16 presentation to the afferent limb of the immune system and potentially an autoimmune response against the protein itself.

Financial support: P.L.L. was funded by the "Fondation ARC pour la Recherche sur le Cancer". P.H. was funded by the "Ligue contre le cancer". K.B. was funded by "Fondation pour la Recherche Médicale" and "Fondation ARC pour la Recherche sur le Cancer". This work was supported by funding from the European Community's Seventh Framework Programme (FP7/2007-2013) n°304810-RAIDs (to A.B., E.D. and M.M.), Inserm, "Fondation ARC pour la recherche sur le cancer" (Projets Fondation ARC to M.M. and A.B.) and the "Ligue contre le cancer" (to A.B.).