Oxaliplatin sensitizes human colon cancer cells to TRAIL through JNK-dependent phosphorylation of Bcl-xL.

International audienceBACKGROUND & AIMS: Oxaliplatin sensitizes drug-resistant colon cancer cell lines to tumor necrosis factor-related apoptosis inducing ligand (TRAIL), a death receptor ligand that is selective for cancer cells. We investigated the molecular mechanisms by which oxaliplatin sensitizes cancer cells to TRAIL-induced apoptosis. METHODS: We incubated the colon cancer cell lines HT29 and V9P, which are resistant to TRAIL, with TRAIL or with oxaliplatin for 2 hours, followed by TRAIL. Annexin V staining was used to measure apoptosis; RNA silencing and immunoblot experiments were used to study the roles of apoptosis-related proteins. Site-directed mutagenesis experiments were used to determine requirements for phosphorylation of Bcl-xL; co-immunoprecipitation experiments were used to analyze the interactions among Bcl-xL, Bax, and Bak, and activation of Bax. RESULTS: Oxaliplatin-induced sensitivity to TRAIL required activation of the mitochondrial apoptotic pathway; reduced expression of Bax, Bak, and caspase-9, and stable overexpression of Bcl-xL, reduced TRAIL-induced death of cells incubated with oxaliplatin. Mitochondrial priming was induced in cells that were sensitized by oxaliplatin and required signaling via c-Jun N-terminal kinase and phosphorylation of Bcl-xL. Mimicking constitutive phosphorylation of Bcl-xL by site-directed mutagenesis at serine 62 restored sensitivity of cells to TRAIL. Co-immunoprecipitation experiments showed that oxaliplatin-induced phosphorylation of Bcl-xL disrupted its ability to sequestrate Bax, allowing Bax to interact with Bak to induce TRAIL-mediated apoptosis. CONCLUSIONS: Oxaliplatin facilitates TRAIL-induced apoptosis in colon cancer cells by activating c-Jun N-terminal kinase signaling and phosphorylation of Bcl-xL. Oxaliplatin-induced sensitivity to TRAIL might be developed as an approach to cancer therapy

Release of c-FLIP brake selectively sensitizes human cancer cells to TLR3-mediated apoptosis

Abstract Toll-like receptor 3 (TLR3) mediates innate immune responses by sensing viral dsRNA, but also induces apoptosis selectively in cancer cells. Our analysis by immunohistochemistry revealed that TLR3 is frequently overexpressed in 130 non-small cell lung cancer (NSCLC) patients’ samples compared with normal bronchial epithelium (P < 0.0001, Mann–Whitney test), supporting the therapeutic potential of TLR3 ligand for this type of cancer. However, a proportion of TLR3-expressing cancer cell lines, including NSCLC, remain resistant to TLR3-mediated apoptosis, and the underlying mechanism of resistance remains unclear. We here investigated the molecular basis conferring resistance to non-transformed vs. transformed cells against TLR3-mediated cell death. In non-transformed epithelial cells cellular FLICE-like inhibitory protein (c-FLIP) and cellular Inhibitor of APoptosis (cIAPs) ubiquitin ligases exerted an efficient double brake on apoptosis signaling. In contrast, releasing only one of these two brakes was sufficient to overcome the resistance of 8/8 cancer cell lines tested. Remarkably, the release of the c-FLIP, but not cIAPs, brake only results in the sensitization of all human cancer cells to TLR3-mediated apoptosis. Taking advantage of the difference between transformed and non-transformed cells, we developed a rational strategy by combining the chemotherapeutic agent paclitaxel, which decreases c-FLIP expression, with TLR3 ligand. This combination was highly synergistic for triggering apoptosis in cancer cells but not in non-transformed cells. In vivo, the combination of paclitaxel with dsRNA delayed tumor growth and prolonged survival in a mouse xenograft lung tumor model. In conclusion, combining the release of the c-FLIP brake with TLR3 ligand synergizes to selectively kill cancer cells, and could represent an efficient and safe therapy against TLR3-expressing cancers such as NSCLC

European Multicenter Study of ET-COVID-19

International audienceBackground and Purpose: Acute ischemic stroke and large vessel occlusion can be concurrent with the coronavirus disease 2019 (COVID-19) infection. Outcomes after mechanical thrombectomy (MT) for large vessel occlusion in patients with COVID-19 are substantially unknown. Our aim was to study early outcomes after MT in patients with COVID-19. Methods: Multicenter, European, cohort study involving 34 stroke centers in France, Italy, Spain, and Belgium. Data were collected between March 1, 2020 and May 5, 2020. Consecutive laboratory-confirmed COVID-19 cases with large vessel occlusion, who were treated with MT, were included. Primary investigated outcome: 30-day mortality. Secondary outcomes: early neurological improvement (National Institutes of Health Stroke Scale improvement ≥8 points or 24 hours National Institutes of Health Stroke Scale 0–1), successful reperfusion (modified Thrombolysis in Cerebral Infarction grade ≥2b), and symptomatic intracranial hemorrhage. Results: We evaluated 93 patients with COVID-19 with large vessel occlusion who underwent MT (median age, 71 years [interquartile range, 59–79]; 63 men [67.7%]). Median pretreatment National Institutes of Health Stroke Scale and Alberta Stroke Program Early CT Score were 17 (interquartile range, 11–21) and 8 (interquartile range, 7–9), respectively. Anterior circulation acute ischemic stroke represented 93.5% of cases. The rate modified Thrombolysis in Cerebral Infarction 2b to 3 was 79.6% (74 patients [95% CI, 71.3–87.8]). Thirty-day mortality was 29% (27 patients [95% CI, 20–39.4]). Early neurological improvement was 19.5% (17 patients [95% CI, 11.8–29.5]), and symptomatic intracranial hemorrhage was 5.4% (5 patients [95% CI, 1.7–12.1]). Patients who died at 30 days exhibited significantly lower lymphocyte count, higher levels of aspartate, and LDH (lactate dehydrogenase). After adjustment for age, initial National Institutes of Health Stroke Scale, Alberta Stroke Program Early CT Score, and successful reperfusion, these biological markers remained associated with increased odds of 30-day mortality (adjusted odds ratio of 2.70 [95% CI, 1.21–5.98] per SD-log decrease in lymphocyte count, 2.66 [95% CI, 1.22–5.77] per SD-log increase in aspartate, and 4.30 [95% CI, 1.43–12.91] per SD-log increase in LDH). Conclusions: The 29% rate of 30-day mortality after MT among patients with COVID-19 is not negligible. Abnormalities of lymphocyte count, LDH and aspartate may depict a patient’s profiles with poorer outcomes after MT. Registration: URL: https://www.clinicaltrials.gov . Unique identifier: NCT04406090