Cisplatin (DDP) was reported to improve pathological complete response (pCR) rates in triple-negative breast cancer (TNBC) patients, however, the molecular mechanism still remains largely unknown. Emerging evidence suggested that some chemotherapeutic drugs played anti-tumor effects by inducing cell pyroptosis. Nevertheless, whether pyroptosis contributes to the DDP-induced anti-tumor effect in TNBC remains unexploited. In the present study, NLRP3/caspase-1/GSDMD pyroptosis pathway was involved in the DDP-induced anti-tumor effect of TNBC in vitro and in vivo , providing evidence that DDP might induce pyroptosis in TNBC. Moreover, DDP activated NLRP3/caspase-1/GSDMD pyroptosis pathway by up-regulating the long non-coding RNA (lncRNA) maternally expressed gene 3 (MEG3). Furthermore, knockdown of MEG3 not only partly abolished the activation effect of DDP on NLRP3/caspase-1/GSDMD pathway-mediated pyroptosis, but also reversed the suppression of DDP on tumor growth and metastasis ability in vitro and in vivo, further confirming that MEG3 may partially mediate the pyroptotic signaling upon DDP treatment. Thus, our data uncovered a novel mechanism that DDP induced pyroptosis via activation of MEG3/NLRP3/caspase-1/GSDMD pathway in TNBC to exert anti-tumor effects, which may help to develop new strategies for the therapeutic interventions in TNBC.
Respiratory syncytial virus (RSV) infection is the leading cause of hospitalization and infant mortality under six months of age worldwide; therefore, the prevention of RSV infection in all infants represents a significant unmet medical need. Here we report the isolation of a potent and broadly neutralizing RSV monoclonal antibody derived from a human memory B-cell. This antibody, RB1, is equipotent on RSV A and B subtypes, potently neutralizes a diverse panel of clinical isolates in vitro and demonstrates in vivo protection. It binds to a highly conserved epitope in antigenic site IV of the RSV fusion glycoprotein. RB1 is the parental antibody to MK-1654 which is currently in clinical development for the prevention of RSV infection in infants.
Blood-brain barrier (BBB) disruption and brain edema formation play important roles in the secondary neuronal death and neurological dysfunction induced by intracerebral hemorrhage (ICH). Poloxamer 188 (P188), a multiblock copolymer surfactant, has been shown to be capable of sealing damaged cell membranes and decrease neuronal cell death. In this study, we explored whether P188 had a protective effect against ICH and its underlying mechanisms. Male ICR mice were subjected to infusion of type IV collagenase (to induce ICH) of saline (for shams) into the left striatum. The results showed that P188-12 mg post-treatment by tail intravenous injection significantly ameliorated the neurological symptoms and brain edema, attenuated BBB permeability, and decreased cell insults and injury volume at 24 and 72 h after ICH. Furthermore, P188 maintained the protein levels of tight junction (TJ) proteins including claudin-5, occludin, and zonula occludens-1, and reversed the increases of nuclear factor-kappaB (NF-κB), matrix metalloproteinase (MMP)-2, and MMP-9 protein expression at 72 h post ICH. Immunofluorescence showed P188 treatment rearranged the structure of TJ proteins in a continuous and linear pattern. Therefore, the present study concludes that P188 can protect against ICH, and the protective effect was associated with preventing BBB disruption through NF-κB-MMPs-mediated TJ proteins degradation.
Necroptosis was recently discovered as one form of programmed cell death (PCD) and could be specifically inhibited by necrostatin-1. The aim of this study was to examine the effect of necrostatin-1 on brain injury and investigate the role of necrostatin-1 on the other two types PCD (apoptosis and autophagic cell death) in a mouse intracerebral hemorrhage (ICH) model. Male ICR mice received an infusion of type IV collagenase to induce ICH or saline as control into the left striatum. In the presence of vehicle, 3-MA, zVAD, and necrostatin-1 were pretreated with a single intracerebroventricular (i.c.v.) injection in the ipsilateral ventricle 15 min before ICH, respectively. Compared with vehicle groups, necrostatin-1 treatment significantly reduced injury volume and propidium iodide-positive cells at 24 and 72 h after ICH. Immunoblotting analysis showed that necrostatin-1 treatment suppressed autophagic-associated proteins (LC3-II, Beclin-1) and maintained p62 at normal level at 24 and 72 h after ICH. In addition, necrostatin-1 treatment enhanced the protein level of Bcl-2 and decreased the protein level of cleaved caspase-3 and the Beclin-1/Bcl-2 ratio at 24 and 72 h after ICH. Moreover, both 3-MA and necrostatin-1 treatment could suppress cleaved caspase-3 and LC3-II production, whereas zVAD treatment could inhibit caspase-3 cleavage but increased LC3-II protein levels at 72 h after ICH. Taken together, the data demonstrated for the first time that the specific inhibitor necrostatin-1 suppressed apoptosis and autophagy to exert these neuroprotective effects after ICH and that there existed a cross-talk among necroptosis, apoptosis, and autophagy after ICH.
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