In T lymphocytes, the role of Akt in regulating Fas/Fas ligand (FasL)-mediated apoptotic signaling and death is not clearly understood. In this study, we observed that inhibition of Akt causes enhanced expression of FasL mRNA and protein and increased death-inducing signaling complex (DISC) formation with Fas-associated death domain (FADD) and procaspase-8 recruitment. Also, caspase-8 was activated at the DISC with accompanying decrease in c-FLIP s expression. FasL neutralizing antibody significantly decreased apoptotic death in the Akt-inhibited T cells. Additionally, Akt inhibition-induced Fas signaling was observed to link to the mitochondrial pathway via Bid cleavage. Further, inhibition of caspase-8 activity effectively blocked the loss of mitochondrial membrane potential and DNA fragmentation, suggesting that DISC formation and subsequent caspase-8 activation are critical initiating events in Akt inhibition-induced apoptotic death in T lymphocytes. These data demonstrate yet another important survival function governed by Akt kinase in T lymphocytes, which involves the regulation of FasL expression and consequent apoptotic signaling.
Natural compounds from medicinal plants are important resources for drug development. Active compounds targeting apoptosis and autophagy are candidates for anti-cancer drugs. In this study, we collected Garcinia species from China and extracted them into water or ethanol fractions. Then, we performed a functional screen in search of novel apoptosis and autophagy regulators. We first characterized the anti-proliferation activity of the crude extracts on multiple cell lines. HeLa cells expressing GFP-LC3 were used to examine the effects of the crude extracts on autophagy. Their activities were confirmed by Western blots of A549 and HeLa cells. By using bioassay guided fractionation, we found that two caged prenylxanthones from Garcinia bracteata, neobractatin and isobractatin, can significantly induce apoptosis and inhibit autophagy. Our results suggest that different Garcinia species displayed various degrees of toxicity on different cancer cell lines. Furthermore, the use of a high content screening assay to screen natural products was an essential method to identify novel autophagy regulators.
Chimeric antigen receptor (CAR) T therapy represents a form of immune cellular therapy with clinical efficacy and a specific target. A typical chimeric antigen receptor (CAR) construct consists of an antigen binding domain, a transmembrane domain, and a cytoplasmic domain. Nanobodies have been widely applied as the antigen binding domain of CAR-T due to their small size, optimal stability, high affinity, and manufacturing feasibility. The nanobody-based CAR structure has shown a proven function in more than ten different tumor-specific targets. After being transduced in Jurkat cells, natural killer cells, or primary T cells, the resulting nanobody-based CAR-T or CAR-NK cells demonstrate anti-tumor effects both in vitro and in vivo. Interestingly, anti-BCMA CAR-T modulated by a single nanobody or bi-valent nanobody displays comparable clinical effects with that of single-chain variable fragment (scFv)-modulated CAR-T. The application of nanobodies in CAR-T therapy has been well demonstrated from bench to bedside and displays great potential in forming advanced CAR-T for more challenging tasks.
BackgroundBronchopulmonary dysplasia (BPD) is a neonatal chronic lung disease characterized by impaired pulmonary alveolar development in preterm infants. Until now, little is known about the molecular and cellular basis of BPD. There is increasing evidence that lncRNAs regulate cell proliferation and apoptosis during lung organogenesis. The potential role of lncRNAs in the pathogenesis of BPD is unclear. This study aims to clarify the role of MALAT1 during the process of BPD in preterm infants and illustrate the protective effect of MALAT1 involved in preterm infants.MethodsWe assessed the expression of MALAT1 in BPD mice lung tissues by reanalyzing dataset GSE25286 (Mouse GEO Genome 4302 Array) from gene expression database gene expression omnibus (GEO), and verified MALAT1 expression in BPD patients by realtime q-PCR. Then the role of MALAT1 in regulating cell biology was examined by profiling dataset GSE43830. The expression of CDC6, a known antiapoptopic gene was verified in BPD patients and the alveolar epithelial cell line A549 cells in which MALAT1 was knocked down. Cell apoptosis was determined by FACS using PI/Annexin-V staining.ResultsThe expression of MALAT1 was significantly evaluated in lung tissues of BPD mice at day 14 and day 29 compared to WT (P < 0.05). In consistent with mRNA array profiling analysis, MALAT1 expression level in blood samples from preterm infants with BPD was significantly increased. Bioinformative data analysis of MALAT1 knockdown in WI-38 cells showed various differentially expressed genes were found enriched in apoptosis related pathway. Down-regulation of antiapoptopic gene, CDC6 expression was further verified by q-PCR result. PI/Annexin-V apoptisis assay results showed that MALAT1 knocked down in the alveolar epithelial cell line (A549) promotes cell apoptosis.ConclusionsIn our study, we found that up-regulation of lncRNA MALAT1 could protect preterm infants with BPD by inhibiting cell apoptosis. These data provide novel insights into MALAT1 regulation which may be relevant to cell fate and shed light on BPD prevention and treatment.Electronic supplementary materialThe online version of this article (10.1186/s12890-017-0524-1) contains supplementary material, which is available to authorized users.
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