Synergism through combination of chemotherapy and oxidative stress-induced autophagy in A549 lung cancer cells using redox-responsive nanohybrids: A new strategy for cancer therapy

A combination of various therapeutic approaches has emerged as a promising strategy for cancer treatment. A safe and competent nano-delivery system is thus in urgent demand to facilitate the simultaneous transport of various therapeutic agents to cancer cells and a tumor region to achieve synergistic effect. Gold nanoparticles (GNPs) and mesoporous silica nanoparticle (MSNs) were fabricated herein as potential candidates for drug delivery. Serving as gatekeepers, GNPs (5 nm in diameter) were attached onto the amino-functionalized MSNs (denoted as NMSNs) via a relatively weak gold–nitrogen bonding. The resulting nanohybrids (denoted as GCMSNs) were uptaken by cells, and the detachment of GNPs and subsequent intracellular drug release from NMSNs were achieved by competitive binding of intracellular glutathione to GNPs. In addition to the function of gatekeeping, GNPs also play another role as the oxidative stress elicitor. Our in vitro studies revealed that GCMSNs induced higher oxidative stress in lung cancer cells (A549) than in normal cells (3T3-L1). This growth inhibitory effect found in the cancer cells was likely induced by mitochondria dysfunction originated from the GCMSN-induced, oxidative stress-triggered mitochondria-mediated autophagy. The redox-responsive nanohybrids were further loaded with camptothecin and the intensified synergistic therapeutic effects were observed associated with combined chemotherapy and oxidative stress strategy. The results clearly demonstrate that such unique nanohybrids hold great promise for selective and effective cancer treatments.     

Is the autophagy a friend or foe in the silver nanoparticles associated radiotherapy for glioma？

Malignant glioma is the most common intracranial tumor with a dismal prognosis. The radiosensitizing effect of silver nanoparticles (AgNPs) on glioma both in vitro and in vivo had been demonstrated in the previous studies of our group. However, the underlying mechanism is still unclear. Consistent with previous studies, a size and dose dependent antitumor effect and significant radiosensitivity enhancing effect of AgNPs were observed in our experiment system. We also found that cell protective autophagy could be induced by AgNPs and/or radiation, which was verified by the use of 3-MA. The mechanism through which had autophagy and the enhancement of radiosensitivity taken place was further investigated with inhibitors of ERK and JNK pathways. We demonstrated that ERK and JNK played pivotal roles in the radiosensitivity enhancement. Inhibiting ERK and JNK with U0126 and SP600125 respectively, we found that the autophagy level of the cells treated with AgNPs and radiation were attenuated. Moreover, SP600125 down-regulated the apoptosis rate of the co-treated cells significantly. Taken together, the present study would have important impact on biomedical applications of AgNPs and clinical treatment for glioma.     

Effects of newly introduced antidiabetic drugs on autophagy

Diabetes mellitus is a chronic metabolic disorder that has a complex molecular and cellular pathophysiology, resulting in its dynamic progression and that may show differing responses to therapy. The incidence of diabetes mellitus increases with age and requires additive therapeutic agents for its management. SGLT2i and DPP-4 inhibitors and GLP-1 receptor agonists (GLP-1RA) are newly introduced antidiabetic drugs that work through differing mechanisms; DPP-4 inhibitors maintain the endogenous level of GLP1; GLP-1RA result in pharmacological levels of GLP1, whilst SGLT2i act on the proximal tubules of the kidney. They have shown efficacy in the management of diabetes and in contrast to other antidiabetic drugs, do not inherently cause hypoglycemia in therapeutic doses. Autophagy as a highly conserved mechanism to maintain cell survival and homeostasis by degradation of damaged or aged organelles and components, and recognised to be increasingly important in diabetes. In the present review, we discuss the modulatory effects of these newly introduced antidiabetic drugs on the autophagy process.     

AMPK通过抑制NLRP3炎症小体参与延缓衰老过程

衰老是在细胞、组织和器官水平上发生的生理性内稳态的渐进性损害过程。就代谢角度而言,该过程主要表现为体成分、胰岛素抵抗、自噬功能障碍、线粒体和炎症反应的变化,其中涉及生长激素、胰岛素/胰岛素样生长因子1及各种能量感应系统如AMP活化蛋白激酶(AMP-activated protein kinase,AMPK).     

In the absence of major histocompatibility complex class II molecules,invariant chain is translocated to late endocytic compartments by autophagy

It has been suggested that the cytoplasmic amino-terminal tail of invariant chain (Ii) contains a sorting signal that directs trafficking of the major histocompatibility complex (MHC) class II: Ii oligomeric complex to endocytic compartments. This model is based, in part, on the observation that in the absence of MHC class II molecules, Ii is detectable in lysosomal structures, a phenotype that is dependent on an intact NH₂ terminus. However, the route by which Ii gains access to endosomal compartments in the absence of class II molecules remains uncertain. Here we report a mechanism that localizes Ii in lysosomal compartments independently of class II. We show that murine Ii can be detected by immunofluorescence within late endocytic compartments of stably transfected Ltk^? mouse fibroblasts. Immunochemical studies indicate that degradation of Ii in these cells is sensitive to the lysosomotropic agent ammonium chloride, yet the majority of Ii that undergoes this apparent lysosomal degradation is sensitive to the enzyme endoglycosidase H. This finding suggests that Ii may reach the lysosomal compartment by a route that bypasses the Golgi complex. Consistent with this possibility, we found that in contrast to Ii which is complexed to class II molecules, transport of free Ii to lysosomes is prevented by 3-methyladenine, an inhibitor of the autophagic pathway of protein degradation, a process which involves direct transport from the endoplasmic reticulum to lysosomes. These data suggest the route of transport that leads to endosomal localization of Ii in the absence of class II is distinct from that taken when expressed with class II. This forces a re-evaluation of the concept that the cytosolic tail of Ii contains a dominant Golgi-to-endosomal sorting signal.     

Ultrastructure of cell death in bulbar cushions of chick embryo heart

Summary The ultrastructure of the physiological cell death was studied in distal ventral bulbar cushions of 15 chick embryo hearts on the 4th and 5th day of incubation. Microperfusion fixation was performed. The ultracytochemistry of a lysosomal hydrolytic enzyme acid phosphatase was also investigated in another 15 embryonic hearts.In the course of the cell degeneration an increase in cellulr autophagy was observed without previous cytoplasmic or nuclear changes or phagocyte ingestion. A cytoplasmic diffusion of acid phosphatase outside of lysosomes was observed.Besides the cell death with the marked participation of the lysosomal system, another kind of dying cells was found, characterized by their nuclear pycnosis and cytoplasmic condensation. Starting from the 5th day of incubation the dying and dead cells were found phagocytized by some of their neighbouring viable mesenchymal cells. A formation of ribosomal crystals was not observed.The formation and fate of cytolysomes as well as the fate of phagocytes are discussed. The presence of pre-necrotic cells with important autophagy and of necrotic cells with nuclear changes was related to the possibility of a dual cause of the cell death. In the case of pre-necrotic cells the epigenetic factors like the biomechanic action of hemodynamics were considered, while the necrotic cells seem to be programmed to death by their genome.Finally the uniformity of cell death ultrastructure in different organs and species was noticed.     

川陈皮素通过激活SIRT1/FOXO3a信号来减轻肾缺血再灌注损伤

目的：本研究旨在探究川陈皮素（NOB）保护小鼠肾缺血再灌注损伤（RIRI）的可能分子机制。方法：将Balb/c小鼠分为5组（n=6）：假手术组、模型组、NOB组（50 mg/kg）、组蛋白去乙酰化酶沉默信息调节因子1（SIRT1）抑制剂EX527组（5 mg/kg）、NOB+EX527组（50 mg/kg的NOB+5 mg/kg EX527）。在建模前24 h对小鼠进行药物处理。通过阻断小鼠左肾动静脉血流建立RIRI模型。建模24 h后检测肾组织中氧化应激标志物含量。通过苏木精-伊红（HE）染色和天狼星红染色评价肾组织病变和纤维化。通过TUNEL染色检测肾细胞凋亡。通过蛋白质免疫印迹法检测肾组织中SIRT1、叉头框蛋白O3a（FOXO3a）、细胞凋亡和自噬相关蛋白表达。通过实时荧光定量PCR检测肾组织中SIRT1和FOXO3a mRNA的水平。结果：与模型组比较,NOB组小鼠肾脏病变程度减轻,肾脏纤维化面积降低（均P<0.05）。与模型组比较,NOB组肾组织抗氧化作用升高（P<0.05）。与模型组比较,NOB组肾组织中细胞凋亡减少（P<0.05）。与模型组比较,NOB组肾组织中SIRT1和FOXO3a的mRNA和蛋白相对表达量升高,微管相关蛋白轻链(LC)3Ⅱ/LC3Ⅰ蛋白相对表达量升高,而p62降低（均P<0.05）。此外,EX527逆转了NOB对肾脏的保护作用（P<0.05）。结论：NOB通过激活SIRT-1/FOXO3a信号通路介导的自噬来减轻RIRI。     

联合多数据库构建肝细胞癌自噬基因预后模型

目的构建自噬基因表达特征的肝细胞癌(hepatocellular carcinoma,HCC)患者预后的预测模型。方法从癌症基因组图谱(The Cancer Genome Atlas,TCGA)、基因型-组织表达研究项目(The Genotype-Tissue Expression,GTEx)数据库中分别得到所有HCC和正常肝细胞组织的基因转录表达数据,并将每个样本的基因转录表达数据统一转化为log2(FPKM值+1),消除数据库之间测试平台的数据差异。根据人类自噬基因库中获取的人类自噬基因列表筛选出TCGA-GTEx整合后序列中每个样本对应的自噬基因的表达量。采用R语言limma包以错误发现率(FDR)<0.05及差异倍数|logFC|>1为筛选标准,进行自噬基因差异表达分析。采用R语言clusterProfiler包对差异表达自噬基因以P<0.05为筛选标准,进行基因本体论(Gene Ontology,GO)富集分析及京都基因与基因组百科全书(Kyoto Encyclopedia of Genes and Genomes,KEGG)富集分析。根据自噬基因的差异表达量和患者的临床信息,采用R语言survival包进行单因素的Cox回归分析。进一步将单因素的Cox回归分析中有统计学意义(P<0.05)的自噬基因纳入到多因素Cox回归分析中,以每个差异表达的自噬基因表达量和相对应的回归系数coef值为基础,构建HCC的自噬基因预后模型:expmRNA1×βmRNA1+expmRNA2×βmRNA2+…+expmRNAn×βmRNAn(exp:基因表达量;β:多因素Cox回归分析的回归系数coef)。绘制预测模型的受试者工作特征(receiver operating characteristic,ROC)曲线并计算ROC曲线下面积(area under curve,AUC)评估模型预测价值。结果从TCGA-GTEx数据库中共得到HCC样本374例和正常肝组织样本160例的基因转录表达数据及临床信息。从整合后的样本序列中共筛选出205个自噬基因的表达数据,其中SPNS1、DIRAS3、TMEM74、NRG2、NRG1、IRGM、IKBKE、NKX2-3、BIRC5、CDKN2A、TP73为符合筛选标准的差异表达自噬基因。差异表达自噬基因GO主要富集在丝氨酸/苏氨酸蛋白激酶活性的调控、ErbB 2信号通路、蛋白激酶调节活性、激酶调节活性等功能。差异表达自噬基因主要富集在EGFR酪氨酸激酶抑制剂耐药、Hippo信号通路等KEGG通路。整合并删除生存信息缺失的样本后,共418例样本表达纳入到Cox回归分析中。通过单因素、多因素Cox风险回归分析后,筛选出NRG1(HR=1.5565,95%CI:1.1793~2.0543)、IKBKE(HR=1.7502,95%CI:1.2093~2.5330)这两个自噬基因并建立预后预测模型:(0.44247×NRG1的表达量)+(0.55977×IKBKE的表达量)。预测模型的ROC曲线显示7年总体生存的AUC为0.711。结论基于NRG1和IKBKE表达量构建的HCC预后模型,对HCC患者远期生存率有较高的预测价值。     

二氢欧山芹通过调节自噬保护高糖诱导的足细胞损伤

目的探讨二氢欧山芹(columbianetin,CBT)对高糖诱导的足细胞损伤保护作用及其机制研究。方法体外培养永生化小鼠足细胞系MPC-5,给予高浓度的葡萄糖刺激,观察CBT对高糖诱导的足细胞损伤及自噬的影响;采用蛋白质印迹法检测足细胞自噬相关蛋白;荧光显微镜观察GFP-LC3-Ⅱ转染后足细胞绿色荧光颗粒。结果高糖诱导足细胞损伤及自噬水平下降;CBT对高糖诱导的足细胞损伤具有显著保护作用,同时可上调自噬水平;CBT可上调TLR4、P-JNK的表达;siRNA TLR4及JNK抑制剂SP600125阻断CBT的保护作用。结论CBT可调节足细胞自噬保护高糖造成的足细胞损伤,这一过程是通过促进TLR4/p-JNK信号通路实现的。