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.

Long non-coding RNA (lncRNA) maternally expressed gene 3 (MEG3) has been demonstrated as an important regulator in diverse human cancers. However, its function and regulatory mechanism in ischemic stroke remains largely unknown. Here, we report that MEG3 is physically associated with microRNA-21 (miR-21), while miR-21 is downregulated following ischemia in the ischemic corein vitroandin vivo, which is opposite to MEG3. Besides, overexpression of miR-21 protects oxygen–glucose deprivation and reoxygenation (OGD/R)-induced apoptotic cell death. Furthermore, MEG3 functions as a competing endogenous RNAs (ceRNAs) and competes with programmed cell death 4 (PDCD4) mRNA for directly binding to miR-21, which mediates ischemic neuronal death. Knockdown of MEG3 protects against ischemic damage and improves overall neurological functionsin vivo. Thus, our data uncovers a novel mechanism of lncRNA MEG3 as a ceRNA by targeting miR-21/PDCD4 signaling pathway in regulating ischemic neuronal death, which may help develop new strategies for the therapeutic interventions in cerebral ischemic stroke.

Background: Emerging evidence supports the pivotal roles of adipocytes in breast cancer progression. Tumour induced beige/brown adipose tissue differentiation contributes to the hypermetabolic state of the breast cancer. However, the mediators and mechanisms remain unclear.Methods: Survival probabilities were estimated using the Kaplan–Meier method based on immunohistochemistry results. Biochemical studies were performed to characterize the novel interrelation between breast cancer cells and adipocytes.Results: We show that tumour-surrounding adipocytes exhibit an altered phenotype in terms of upregulated beige/brown characteristics and increased catabolism associated with an activated state characterized by the release of metabolites, including free fatty acids, pyruvate, lactate and ketone bodies. Likewise, tumour cells cocultivated with mature adipocytes exhibit metabolic adaptation and an aggressive phenotype in vitro and in vivo. Mechanistically, we show that tumour cells induce beige/brown differentiation and remodel metabolism in resident adipocytes by exosomes from the co-culture system that carry high levels of miRNA-144 and miRNA-126. miRNA-144 promotes beige/brown adipocyte characteristics by downregulating the MAP3K8/ERK1/2/PPARγ axis, and exosomal miRNA-126 remodels metabolism by disrupting IRS/Glut-4 signalling, activating the AMPK/autophagy pathway and stabilizing HIF1α expression in imminent adipocytes. In vivo inhibition of miRNA-144 or miRNA-126 decreases adipocyte–induced tumour growth.Conclusions: These results demonstrate that by inducing beige/brown differentiation and enhancing catabolism in recipient adipocytes, exosomal miRNA-144 and miRNA-126 from the tumour-adipocyte interaction reprogram systemic energy metabolism to facilitate tumour progression.

Cancer-associated adipocytes (CAAs), as a main component of the tumor-adipose microenvironment (TAME), have various functions, including remodeling the extracellular matrix and interacting with tumor cells or infiltrated leukocytes through a variety of mutual signals. Here, we summarize the primary interplay among CAAs, the immune response and cancer with a focus on the mechanistic aspects of these relationships. Finally, unifying our understanding of CAAs with the immune cell function may be an effective method to enhance the efficacy of immunotherapeutic and conventional treatments.