CXCL5-mediated accumulation of SiglecFhigh neutrophils in lung tumor tissues impairs CD8 T cell responses and limits the efficacy of PD-L1 checkpoint blockade

Neutrophils are recruited in different type of cancer, including lung cancer, where they emerged as the most significant negative prognostic factor. Most experimental reports converge toward a rotumorigenic role of neutrophils via direct induction of cancer cell proliferation, promotion of metastasis, stimulation of angiogenesis and modulation of T cell responses. Nevertheless, in some cancer type and tumor stages, neutrophils exert anti-tumoral properties through direct killing of cancer cells and activation of T cell-dependent anti-tumor immunity. Thus, neutrophils in cancer display an enormous plasticity and heterogeneity which may be strongly influenced by the tissue and the constellation of immune modulating factors. Evaluate the complexity of neutrophils in tissue specific tumor microenvironment to unequivocal distinguish immunosuppressive neutrophils from other neutrophil subsets represent an important challenge in the field. In addition, understanding how these cells accumulate in tissues and how polarize to a pro- or anti-tumorigenic phenotype is crucial to develop successful cancer therapies. A critical subset of neutrophils expressing high levels of the sialic-acid-binding protein SiglecF (neuSiglecFhigh) was identified in KrasG12D/+; Trp53-/-(KP) mouse lung adenocarcinoma that correspond to a transcriptionally related human counterpart associated to negative outcomes. Neu-SiglecFhigh are mature, long-lived, cells that display tumor promoting functions associated to angiogenesis, matrix remodeling and production of ROS. However, the mechanism of recruitment of neu-SiglecFhigh in lung cancer and their impact on endogenous anti-tumor T cell responses are still unknown.Here, we used a transplantable KP line to investigate the role of the C-X-C motif chemokine 5 (CXCL5) in recruitment and accumulation of neu-SiglecFhigh in the microenvironment of lung tumors. By genome editing we abrogated the expression of CXCL5 in immunogenic KP cells (KP OVA KOCXCL5) and we characterized neutrophils frequencies and T cell activation within lung tumor tissues. We observed a drastic decrease of Cxcl5 transcripts followed by a strong reduction of neu-SiglecFhigh in KOCXCL5 tumors proving that the chemokine is a key player for their accumulation. Moreover, phenotypic and functional analysis of endogenous anti-cancer responses revealed a significant expansion of highly activated and cytotoxic tumor specific CD8+ T cells in tumor lacking neuSiglecFhigh. Immunofluorescence analysis of lung tissues shown tight CD8 T cell-neutrophils interactions, suggesting a contact-mediated mechanism of inhibition. Moreover, administration of antibodies to PD-L1 during challenge proved that neu-SiglecFhigh, due to a high expression of PD-L1, hamper the full activity of checkpoint blockade. Thus, we infer that targeting the CXCL5-axis could be a viable improvement to existing immunotherapy

Ischemic wound revascularization by the stromal vascular fraction relies on host-donor hybrid vessels

Nonhealing wounds place a significant burden on both quality of life of affected patients and health systems. Skin substitutes are applied to promote the closure of nonhealing wounds, although their efficacy is limited by inadequate vascularization. The stromal vascular fraction (SVF) from the adipose tissue is a promising therapy to overcome this limitation. Despite a few successful clinical trials, its incorporation in the clinical routine has been hampered by their inconsistent results. All these studies concluded by warranting pre-clinical work aimed at both characterizing the cell types composing the SVF and shedding light on their mechanism of action. Here, we established a model of nonhealing wound, in which we applied the SVF in combination with a clinical-grade skin substitute. We purified the SVF cells from transgenic animals to trace their fate after transplantation and observed that it gave rise to a mature vascular network composed of arteries, capillaries, veins, as well as lymphatics, structurally and functionally connected with the host circulation. Then we moved to a human-in-mouse model and confirmed that SVF-derived endothelial cells formed hybrid human-mouse vessels, that were stabilized by perivascular cells. Mechanistically, SVF-derived endothelial cells engrafted and expanded, directly contributing to the formation of new vessels, while a population of fibro-adipogenic progenitors stimulated the expansion of the host vasculature in a paracrine manner. These data have important clinical implications, as they provide a steppingstone toward the reproducible and effective adoption of the SVF as a standard care for nonhealing wounds

Downregulation of Membrane Trafficking Proteins and Lactate Conditioning Determine Loss of Dendritic Cell Function in Lung Cancer

International audienc

Impact of variations in triage cytology interpretation on human papillomavirus–based cervical screening and implications for screening algorithms

AbstractBackgroundWomen positive to human papillomavirus (HPV+) testing at cervical screening need triage, typically cytology and immediate colposcopy in case of atypical squamous cells of undetermined significance (ASCUS) or worse (ASCUS+) or, in cytology-normal HPV+ women, HPV test repeat after 1 year and colposcopy referral if still HPV+. Our hypothesis was that substantial variations in triage positivity and sensitivity may produce little variation in overall referral to colposcopy and on sensitivity of the entire screening process.MethodsCentre- and age-aggregated data from 72,869 women aged 35–64 years were derived from 10 organised screening programmes which have piloted HPV screening in Italy since 2012. Overall colposcopy referral was evaluated as a function of immediate colposcopy referral and overall CIN2+ detection as a function of the proportion of all CIN2+ detected by immediate referral (a proxy of cytology's sensitivity). We fitted additive regression models, adjusted for centre, age, compliance to HPV retesting and to colposcopy, by generalised estimation equations.ResultsThe proportion of HPV+ women directly referred to colposcopy varied across programmes (20–57%; average 37%) and so did CIN2+ detection (49–94%; average 77%). Overall, 63% (range 41–75%) of HPV+ were referred to colposcopy either immediately or at HPV repeat. An absolute 10% increase in immediate colposcopy referral resulted in 4.2% (95% CI: 3.3–5.1%) increase in overall referral. An absolute 10% increase in cytology's sensitivity resulted in a 1.1% (95% CI: 0.1–2.0%) increase in overall CIN2+ detection.ConclusionsRepeat HPV testing limits the effect of subjectivity of cytology interpretation on overall referral and sensitivity. These will change only slightly when replacing cytology with another test if the interval to HPV repeat remains unchanged