Cytotoxic therapy for breast cancer inhibits the growth of primary tumors, but promotes metastasis to the sentinel lymph nodes through the lymphatic system. However, the effect of first-line chemotherapy on the lymphatic endothelium has been poorly investigated. In this study, we determined that paclitaxel, the anti-cancer drug approved for the treatment of metastatic or locally advanced breast cancer, induces lymphatic endothelial cell (LEC) autophagy to increase metastases. While paclitaxel treatment was largely efficacious in inhibiting LEC adhesion, it had no effect on cell survival. Paclitaxel inhibited LEC migration and branch point formation by inducing an autophagy mechanism independent of Akt phosphorylation. In vivo, paclitaxel mediated a higher permeability of lymphatic endothelium to tumor cells and this effect was reversed by chloroquine, an autophagy-lysosome inhibitor. Despite a strong effect on reducing tumor size, paclitaxel significantly increased metastasis to the sentinel lymph nodes. This effect was restricted to a lymphatic dissemination, as chemotherapy did not affect the blood endothelium. Taken together, our findings suggest that the lymphatic system resists to chemotherapy through an autophagy mechanism to promote malignant progression and metastatic lesions. This study paves the way for new combinative therapies aimed at reducing the number of metastases.

Background The delayed diagnosis of acute kidney injury (AKI) episodes and the lack of specificity of current single AKI biomarkers hamper its management. Urinary peptidome analysis may help to identify early molecular changes in AKI and grasp its complexity to identify potential targetable molecular pathways. Methods In derivation and validation cohorts totalizing 1170 major cardiac bypass surgery patients and in an external cohort of 1569 intensive care unit (ICU) patients, a peptide-based score predictive of AKI (7-day KDIGO classification) was developed, validated, and compared to the reference biomarker urinary NGAL and NephroCheck and clinical scores. Results A set of 204 urinary peptides derived from 48 proteins related to hemolysis, inflammation, immune cells trafficking, innate immunity, and cell growth and survival was identified and validated for the early discrimination (< 4 h) of patients according to their risk to develop AKI (OR 6.13 [3.96–9.59], p < 0.001) outperforming reference biomarkers (urinary NGAL and [IGFBP7].[TIMP2] product) and clinical scores. In an external cohort of 1569 ICU patients, performances of the signature were similar (OR 5.92 [4.73–7.45], p < 0.001), and it was also associated with the in-hospital mortality (OR 2.62 [2.05–3.38], p < 0.001). Conclusions An overarching AKI physiopathology-driven urinary peptide signature shows significant promise for identifying, at an early stage, patients who will progress to AKI and thus to develop tailored treatments for this frequent and life-threatening condition. Performance of the urine peptide signature is as high as or higher than that of single biomarkers but adds mechanistic information that may help to discriminate sub-phenotypes of AKI offering new therapeutic avenues.

Down-regulation of the enzymes involved in the tryptophan-derived nicotinamide adenine dinucleotide (NAD+) production was identified after acute kidney injury (AKI) leading to the hypothesis that supplementation with nicotinamide (NAM) may increase the kidney NAD+ content leading to rescue of tryptophan pathways, and subsequently improved the kidney outcomes. In this translational study, we identified in 167 cardiac bypass surgery patients a significant decrease of urinary tryptophan and kynurenin in patients developing AKI, irrespective of the KDIGO stage. Although a significant difference was observed, tryptophan and kynurenin moderately discriminated for the development of all AKI KDIGO stages (AUC 0.82 [0.75-0.88] and 0.75 [0.68-0.83], respectively) and severe KDIGO 2-3 stage AKI (AUC 0.71 [0.6-0.81] and 0.66 [0.55-0.77], respectively). Sparked by this confirmation in humans, we aimed to confirm the potential preventive effect of NAM supplementation in wild-type male and female C57BL/6 mice subjected to ischemic AKI (bilateral clamping of renal arteries for 25 minutes). NAM supplementation had no effect on renal function (BUN at day 1, sinistrin-FITC GFR), architecture (Schiff’ periodic acid staining) and injury or inflammation (Kim1 and Il18 mRNA expression). In addition, NAM supplementation did not increase post-AKI NAD+ kidney content. Notwithstanding the potential role of NAM supplementation in the setting of basal NAD+ deficiency, our findings in mice and the reanalysis of published data do not confirm that NAM supplementation can actually improve renal outcome after ischemic AKI in unselected animals and probably patients.