Regulatory Mechanisms Of Apoptosis Research Articles

High temperature-induced Cscaspase-8 disrupts the developmental relationship between Chilo suppressalis and its endoparasitoid

Host hemolymph is an important place of growth and development for most endoparasitoids. Immunofluorescence assay showed that parasitism induced Chilo suppressalis larvae to produce large numbers of granulocytes, but high temperatures led to granulocytes apoptosis and loss of phagocytosis. In addition, high temperatures activated the endoplasmic reticulum apoptotic pathway, leading to apoptosis of prohemocytes. In the present study, the initiator Cscaspase-8 was obtained from the rice pest C. suppressalis. The results of real-time PCR showed that Cscaspase-8 expression was highest in hemocytes; furthermore, transcription was most highly in female adults. Cscaspase-8 was significantly induced when larvae were exposed to 39 °C for a 2-h period. Cscaspase-8 expression was significantly elevated after 2 d of parasitism. Results of the interference test showed that the survival rate of C. suppressalis larvae is not affected by Cscaspase-8 gene silencing under high temperature and parasitism stress. However, developmental delays were observed in Cotesia chilonis larvae when the host Cscaspase-8 gene was knocked down. These results contribute to the current knowledge on the regulatory mechanisms of apoptosis in insects subjected to high temperature and parasitism stress.

Mechanistic study of heat shock protein 60-mediated apoptosis in DF-1 cells

Heat shock proteins (HSP) are a group of highly conserved molecular chaperones found in various organisms and have been associated with tumorigenesis, tumor progression, and metastasis. However, the relationship between HSP60 and apoptosis remains elusive. The aim of this study was to explore the role and regulatory mechanisms of apoptosis in response to altered HSP60 expression. We generated DF-1 cell lines of both HSP60 overexpression and knockdown and assessed their impact on apoptosis levels using ELISA and flow cytometry analyses. Additionally, we examined the transcription and protein expression levels of apoptosis-related signaling factors using fluorescence quantitative PCR (qPCR) and Western blotting analyses. Heat shock proteins 60 overexpression led to a significant decrease in apoptosis levels in DF-1 cells, which could be attributed to the downregulation of BAX and BAK expression, the upregulation of Bcl-2, and the decreased expression of Caspase 3. Conversely, HSP60 knockdown led to a substantial increase in apoptosis levels in DF-1 cells, facilitated by the downregulation of BAX and Bcl-2 expression, and the upregulation of BAK expression, which increased Caspase 3 levels, thereby promoting apoptosis. The findings of our study provide the first evidence of the inhibitory effect of HSP60 on apoptosis in DF-1 cells. These observations have significant implications for disease progression and cancer research, with potential medical applications.

Triploidization of rainbow trout affects proteins related to ovary development and reproductive activity

Rainbow trout are characterized by high amenability to chromosome manipulations during early development to produce androgens, gynogens, or sterile triploids, which are relevant in aquaculture. An understanding of the mechanisms affecting oogenesis and those resulting in diminished gonadal development in triploids is an important area of scientific study. Therefore, the aim of this study was to compare the ovary proteome from triploid (3 N) and diploid (2 N) rainbow trout females using tandem mass tag (TMT) peptide labelling coupled with liquid chromatography–mass spectrometry (LC–MS/MS) to identify differentially expressed proteins (DEPs) between 2 N and 3 N. The potential biological role of DEPs was also explored using comparative functional gene set enrichment to designate the potential protein markers of 3 N sterility. We identified a total of 3899 DEPs (q < 0.05), including 956 downregulated and 2943 upregulated proteins in 3 N ovaries compared to 2 N ovaries. The identified clusters for downregulated proteins in 3 N included lipid metabolic process, hormone biosynthesis, transport and exocytosis, cell junction organization and sperm-egg recognition, which can result in (i) the disruption of lipid, steroid hormone and vitellogenesis processes, (ii) impaired amino acid uptake, (iii) defects in cell–cell junctions reflecting tissue abnormalities and aberrant gonadal morphology, and (iv) impaired functions related to maintaining the proper structure of the vitelline envelope, oocyte formation and fertilization competence. With respect to upregulated proteins in 3 N ovaries, RNA processing, cell cycle, cytoskeleton organization and regulation of metabolic process were the primary clusters, which may reflect (i) the disturbance to RNA processing responsible for impairment of ovary development in triploid rainbow trout, (ii) disruption of spindle formation, incorrect chromosome alignment and segregation during meiotic division, (iii) increase in regulatory mechanism of apoptosis, which in consequence can provoke abnormal gonadal development and sterility, and (iv) enhanced ubiquitin–proteasome system governing aberrant gonadal morphology in 3 N females and oocyte maturation. The obtained results provide an accurate portrait of molecular changes in rainbow trout ovaries in response to triploidization and may contribute to a better understanding of the mechanisms responsible for impaired oogenesis in rainbow trout triploid females, which in turn leads to their sterility. Data are available via ProteomeXchange with identifier PXD034492.

Baihui (DU20), Shenmen (HT7) and Sanyinjiao (SP6) target the cAMP/CREB/BDNF and PI3K/Akt pathways to reduce central nervous system apoptosis in rats with insomnia

Insomnia can cause damage to function and other medical and mental illnesses, and it is also a risk factor for increasing medical care costs. Although simple behavior intervention is feasible in primary medical institutions, the lack of corresponding technical training has obviously restricted its use, patients' autonomy dependence is generally poor, and early missions have some difficulties. Relatively speaking, acupuncture in traditional therapy is more likely to be accepted, but the mechanism is still unclear. In this study, a model of insomnia was constructed using chlorophenylalanine (PCPA) in 6-week-old male SD rats. Electroacupuncture was used to stimulate Baihui (DU20), Shenmen (HT7), and Sanyinjiao (SP6), and the behavior, histopathology, cAMP/CREB/BDNF, PI3K/Akt pathways and the expression of sleep-related factors were observed. Our study showed that IL-1β, PGD2, MT, IL-10, IL-6, TNF-α, IFN-γ and CORT in rats could be regulated after electroacupuncture stimulation. The expression of TrkB, PI3K, Akt, P-TrkB, p-Akt, cAMP, CREB, and BDNF can also be up- or downregulated. Apoptosis-related Bax, Bad and Caspase-3, as well as the monoamine neurotransmitters 5-HT, DA, NE and EPI, were also modulated by electroacupuncture. Taken together, these data illustrate the potential of DU20, HT7 and SP6 as a multitargeted therapy for insomnia in rats. The novelty of the study lies in the description of the Traditional Chinese Medicine stimulation methods different from Chinese Herbs: electroacupuncture stimulates acupoints of sleep factors, cAMP/CREB/BDNF, PI3K/Akt pathways and the multipath and multitarget body response regulation mechanism of apoptosis.

Chronic neurogenic pain inducing chemiluminescence of mitochondrial associates in cardiomyocytes.

e21560 Background: Mitochondrial dysfunction is has a significant impact on the development of heart disease and is a characteristic feature of the heart physiopathology. Our purpose was to analyze some mechanisms of apoptosis regulation and self-organization in the mitochondria of the heart cells in mice with melanoma growing in presence of chronic neurogenic pain (CNP). Methods: The study included female C57BL/6 mice (n = 105) divided into groups: intact animals (n = 21); controls (C, n = 21) with a CNP model created by bilateral sciatic nerve ligation under xylazine/zoletil anesthesia; main group (CNP+B16/F10, n = 63) with B16/F10 melanoma transplanted after CNP creation. After decapitation, mitochondria of the heart were isolated by differential centrifugation. Levels of cytochrome C (ng/mg of protein), caspase 9 (ng/mg of protein), Bcl-2 (ng/mg of protein), AIF (ng/mg of protein), Ca2+ (mmol/g of protein) were determined in mitochondrial samples by ELISA. Results: CNP downregulated levels of Ca2+ by 3.2 times, Bcl-2 by 1.3 times (p &lt; 0.05) and caspase 9 by 1.5 times (p &lt; 0.05), compared to intact mice. AIF levels, on the contrary, were elevated by 2.3 times, and cytochrome C did not differed statistically significantly from intact values. After a week of B16/F10 growth in presence of CNP, levels of Ca2+ in the mitochondria of the heart increased by 5.3 times relative to C values. Further on, Ca2+ decreased to almost undetectable values. The AIF levels changed abruptly: after 1 week it increased by 3.7 times, after 2 weeks it declined to C levels, and after 3 weeks it became 5.2 times lower than in C and 2.3 times lower than in intact animals. Bcl-2 and cytochrome C changed similarly: Bcl-2 after 1 week of melanoma growth in presence of CNP increased 1.7 times (p &lt; 0.05) compared to C, and then after 2-3 weeks it declined and became on average 2.2 times lower than in the mitochondria of the C group; levels of cytochrome C after 1 week did not differed significantly from the values in C, and after 2-3 weeks they decreased by 2.2 times. The levels of caspase 9 in CNP+B16/F10 were on average 2.4 times higher than C values throughout the study. The cold light of high brightness - chemiluminescence was recorded in samples of mitochondrial suspension after 2-3 weeks of CNP+B16/F10. The glow in heart mitochondrial samples was accompanied by bright flashes and a 10-15 second intense white glow with a gradual fading and settling of a large filamentous aggregation of mitochondria on the substrate layer. CNP contributed to the energy supply system blocking in the energy systems of cardiomyocytes. Conclusions: Mitochondrial mechanisms of apoptosis and self-organization of subcellular energy structures in the conditions of malignant tumor growth in presence of CNP are mediated by disruption of polyenzymatic apoptosis regulation systems, and a high level of oxidative stress that induces chemiluminescence of cardiomyocyte mitochondrial associates.

Multi-armed tetrahedral DNA probes for visualizing the whole-course of cell apoptosis by simultaneously fluorescence imaging intracellular cytochrome c and telomerase

Visualization of cell apoptosis can effectively assist early disease diagnosis, precisely reveal pathogenic mechanisms and continuously evaluate curative effect. However, monitoring partial stage of the apoptosis can not accurately or even mistakenly illustrate the apoptotic pathways. Herein, a novel tetrahedral DNA probe (TDNA-WCP) consists of a multi-armed tetrahedral DNA and three special sensing arms for simultaneously fluorescence imaging cytochrome c (Cyt c) and telomerase is proposed to visualize the early and late stages (i.e. whole-course) of cell apoptosis with highly temporal and spatial consistency. The TDNA-WCPs possessing good sensitivity, selectivity, stability and biocompatibility, show attractive performance on real-time, sensitive and specific visualization of intracellular Cyt c and telomerase, and have strong abilities to monitor the oxidative stress of cells and evaluate the drug efficacy, which can be a potential and interesting tool for studying molecular mechanisms of apoptosis regulation or screening the apoptosis-based drugs.

Regulation of apoptosis by Pacific oyster Crassostrea gigas reveals acclimation strategy to CO2 driven acidification

Ocean acidification (OA) has posed formidable threats to marine calcifiers. In response to elevated CO2 levels, marine calcifiers have developed multiple strategies to survive, such as taking advantage of apoptosis, but its regulation mechanism remains largely unknown. Here, we used the Pacific oyster Crassostrea gigas as model to understand the apoptotic responses and regulation mechanism at short- (7 d) to long-term (56 d) CO2 exposure (pH = 7.50). The apoptosis of hemocytes was significantly induced after short-term treatment (7–21 d) but was suppressed under long-term CO2 exposure (42–56 d). Similarly, caspase-3 and caspase-9 were also increased post short-term exposure and fell back to normal levels after long-term exposure. These data together indicated diverse regulation mechanisms of apoptosis through different exposure periods. Through analysis of the B-cell lymphoma 2 (Bcl-2) family mitochondrial apoptosis regulators, we showed that only CgBcl-XL’s expression kept at high levels after 42- and 56-day CO2 exposure. CgBcl-XL shared sequence, and structural similarity with its mammalian counterpart, and knockdown of CgBcl-XL in hemocytes via RNA interference promoted apoptosis. The protein level of CgBcl-XL was significantly increased after long-term CO2 exposure (28–56 d), and its distribution in hemocytes became more concentrated and dense. Therefore, CgBcl-XL serves as an essential anti-apoptotic protein for tipping the balance of cell apoptosis, which may play a key role in survival under long-term CO2 exposure. These results reveal a potential adaptation strategy of oysters towards OA and the variable environment changes through the modulation of apoptosis.

Clinical significance of expression of fibrous sheath interacting protein 1 in colon cancer.

BACKGROUNDThe occurrence and development of colon cancer are complex, involving a variety of genetic changes, such as mutation and activation of oncogenes, inactivation of tumour suppressor genes, and aberrant proliferation and apoptosis regulation mechanisms. Fibrous sheath interacting protein 1 (FSIP1) is a newly discovered oncogene that is frequently activated in a variety of tumours such as breast cancer and bladder cancer. However, the clinical significance of FSIP1 in colon cancer is unclear. In this study, we analysed the clinical significance of expression of FSIP1 in human colon cancer, aimed to clarify the biological role of FSIP1 in the development and progression of colon cancer.AIMTo investigate the clinical significance of expression of FSIP1 in colon cancer.METHODSFrom March 2011 to March 2014, 302 specimens of tumour tissues and paracancerous tissues were obtained from patients pathologically diagnosed with colon cancer at Shengjing Hospital of China Medical University. Immunohistochemistry was used to detect FSIP1 expression in colon cancer tissues and adjacent normal tissues. Spearman correlation coefficient and Cox regression analyses were used to determine the relationship between FSIP1 expression and clinicopathological factors and prognosis, as well as the impact on survival.RESULTSCompared with its expression in adjacent normal tissues, FSIP1 was expressed at higher levels in colon cancer tissues. Spearman correlation analysis showed that high expression of FSIP1 was positively correlated with clinicopathological stage, lymph node metastasis, and poor prognosis in colon cancer; it was negatively correlated with the degree of tumour differentiation. Cox regression analysis showed that high FSIP1 expression was an independent risk factor for the prognosis of colon cancer patients.CONCLUSIONHigh expression of FSIP1 may be one of the important factors affecting the clinical outcome of colon cancer patients and leading to poor prognosis.

Bax protein as a prognostic marker in colorectal cancer: characteristics, role in apoptosis regulation, and correlation with disease prognosis (literature review)

This review analyzes clinical significance of Bax biomarker in colorectal cancer. We cover the most important characteristics of this protein, describe its role in the apoptosis regulation mechanisms, and asses its prognostic value. Despite the fact that multiple studies have significantly improved our knowledge of Bax expression in colorectal cancer, its impact on the disease prognosis remains poorly understood. Many issue related to its correlation with clinical and morphological characteristics of the tumor still have to be clarified.

Yinchenhao decoction suppresses rat liver fibrosis involved in an apoptosis regulation mechanism based on network pharmacology and transcriptomic analysis

Yinchenhao decoction (YCHD) is a classical Traditional Chinese Medicine (TCM) formula that has been widely used in the treatment of liver fibrosis caused by chronic hepatitis B and jaundice for more than 1800 years. The purpose of this study was to investigate the apoptosis regulation mechanisms of YCHD and its active components suppresses liver fibrosis. The active components and putative targets of YCHD were predicted by network pharmacology approach. Functional and pathway enrichment analysis were presented in the present study by using clusterProfiler. Further, experimental validation was done by using terminal deoxynucleotidyl transferase (TDT) dUTP nick end labelling (TUNEL) assay and western blotting in dimethylnitrosamine (DMN)-induced liver fibrosis rats, and cell proliferation assay, apoptosis assay, and western blotting in human hepatic L02 cells and LX2 cells. 45 active compounds in YCHD formula, 592 potential target proteins and 1191 liver fibrosis-related human genes were identified. Functional and pathway enrichment analysis indicated that YCHD obviously influenced TNF, PI3K-Akt signaling pathways. Further, In vivo experiment indicated that YCHD treatment not only attenuated the symptoms of liver fibrosis, but also decrease the apoptosis of hepatic parenchyma cells. Moreover, in vitro experiments showed that rhein, kaempferol and quercetin treatments remarkably decreased the protein levels of cleaved caspase-3 and increased p-ERK1/2, PI3K and Bcl-XL protein expression in TNF-α-stimulated L02 cells. On the contrary, rhein, kaempferol, aloe-emodin and quercetin inhibited the proliferation of LX2 cells and up-regulated the protein levels of Bax and cleaved caspase-8. In conclusion, 45 active components and 296 potential targets of YCHD against liver fibrosis were identified by the analysis of network pharmacology and transcriptomics combination. The mechanisms of YCHD against liver fibrosis were involved in the regulation of multiple targets, especially affecting the apoptosis-related signaling pathways.

An enhanced silver nanocluster system for cytochrome c detection and natural drug screening targeted for cytochrome c

A label-free and turn-off fluorescence method for detecting cytochrome c (Cyt c) was developed using enhanced DNA-templated silver nanoclusters (DNA-AgNCs@tween 80) as a novel fluorescence-enhancing nanoprobe. Cyt c-induced electron transfer between Cyt c and DNA-AgNCs results in a significant fluorescence quenching effect of DNA-AgNCs. The coated tween 80 around DNA-AgNCs particles significantly causes fluorescence signal enhancement in the solution. Meanwhile, the efficiency of fluorescence quenching by Cyt c increases substantially by adding 0.1% tween 80 (final volume concentration) into the detection system. Based on these findings, a simple method with the detection limit of 0.8 nM was established for Cyt c based on tween 80 enhanced DNA-AgNCs. A good linear relationship between the fluorescent intensity and the concentration of Cyt c ranging from 0.8 nM to 20,000 nM (R2 = 0.9910) was obtained. Consequently, the method was applied to monitor the Cyt c variation in HCT-116 and BGC-823 tumor cell culture medium after being treated with doxorubicin (DOX)and two kinds of natural compounds (J5 and S6, extracted from plants Abacopteris Penangiana and Swertia punicea Hemsl, respectively). The results indicate that the level of Cyt c in cell culture medium decreases according to the presence of DOX, J5 and S6. The reliability of the result was further confirmed by using cell viability assay and flow cytometry for apoptosis analysis (FACS). From these data, it can be concluded that this groundbreaking nanoprobe with high sensitivity, great simplicity and good biocompatibility boosts a promising outlook for exploring the molecular mechanisms of apoptosis regulation and nature drugs screening.

Regulation of apoptosis-related genes during interactions between oyster hemocytes and the alveolate parasite Perkinsus marinus

The alveolate Perkinsus marinus is the most devastating parasite of the eastern oyster Crassostrea virginica. The parasite is readily phagocytosed by oyster hemocytes, but instead of intracellular killing and digestion, P. marinus can survive phagocytosis and divide in host cells. This intracellular parasitism is accompanied by a regulation of host cell apoptosis. This study was designed to gain a better understanding of the molecular mechanisms of apoptosis regulation in oyster hemocytes following exposure to P. marinus. Regulation of apoptosis-related genes in C. virginica, and apoptosis-regulatory genes in P. marinus, were investigated via qPCR to assess the possible pathways involved during these interactions. In vitro experiments were also carried out to evaluate the effect of chemical inhibitors of P. marinus antioxidant processes on hemocyte apoptosis. Results indicate the involvement of the mitochondrial pathway (Bcl-2, anamorsin) of apoptosis in C. virginica exposed to P. marinus. In parallel, the antioxidants peroxiredoxin and superoxide dismutase were regulated in P. marinus exposed to C. virginica hemocytes suggesting that apoptosis regulation in infected oysters may be mediated by anti-oxidative processes. Chemical inhibition of P. marinus superoxide dismutase resulted in a marked increase of reactive oxygen species production and apoptosis in infected hemocytes. The implication of oxygen-dependent apoptosis during P. marinus infection and disease development in C. virginica is discussed.

Antagonistic effects of different selenium sources on growth inhibition, oxidative damage, and apoptosis induced by fluorine in broilers

Fluorosis can induce oxidative stress through leading to reactive oxygen species (ROS) generation. Selenium (Se) can eliminate ROS by direct and indirect manners. In this study, therefore, we investigated the possible protective effects of sodium selenite (SS) and selenomethionine (Se-Met) on fluorine (F)-induced oxidative stress in broilers. A total of 720 1-day-old Lingnan Yellow broilers were allotted to 4 groups (6 replicates of 30 birds each group) and fed with basal diet (control group), 800mg/kg F (high F group), 800mg/kg F+0.15mg Se/kg as SS (SS group), or Se-Met (Se-Met group), respectively. The experiment lasted 50 d. High F group significantly decreased (P < 0.05) the average daily gain (ADG) and feed efficiency (FE) in comparison with control group. The contents of ROS, malondialdehyde, 8-hydroxydeoxyguanosine, protein carbonyl, and cysteinyl aspartate specific proteinases 3 in serum, liver, and kidney were higher (P < 0.05) in high F group than those in control group. Compared with control group, the decreased (P < 0.05) activities of glutathione peroxidase (GSH-Px) and cytoplasmic thioredoxin reductase (TrxR1) as well as contents of selenoprotein P (SelP), total protein (TP), and B-cell lymphoma-2 in serum and tissues were observed in high F group. Moreover, the pathological lesions of liver and kidney in high F group were more than those in control group. However, supplementation with SS and Se-Met could improve ADG and FE, increase SelP and TP concentrations, elevate GSH-Px and TrxR1 activities, minimize the changes of oxidative stress and apoptosis parameters as well as ultrastructure of liver and kidney, whereas the effects of Se-Met were better than those of SS. The results indicated that excess F could result in growth inhibition of broilers through inducing oxidative stress and subsequently caused oxidative damage to biological macromolecules and soft tissues as well as apoptosis, whereas dietary SS and Se-Met supplementation could antagonize high F induced growth retardation by inhibiting oxidative stress and a mechanism of apoptosis regulation and the impact was more with Se-Met.

Role of MiR-98 and Its Underlying Mechanisms in Systemic Lupus Erythematosus.

T-lymphocyte apoptosis plays a critical role in the pathogenesis of systemic lupus erythematosus (SLE). However, the underlying regulatory mechanisms of apoptosis in SLE remain unclear. The aim of this study was to explore the role of miR-98 in SLE and its underlying mechanisms. Western blotting and quantitative reverse transcription PCR (qRT-PCR) were used to analyze miR-98 and Fas expression. Luciferase reporter assays were performed to identify miR-98 targets. To modify miRNA levels, miR-98 mimics and inhibitor were transfected into cells. A lentiviral construct was used to overexpress the level of Fas in SLE CD4+ T cells. Gene and protein expression were determined by qRT-PCR and Western blotting. Apoptosis levels were evaluated by annexin V staining and flow cytometry. Compared to those of healthy donors, miR-98 was downregulated in SLE CD4+ T cells, whereas Fas mRNA and protein expression were upregulated. Upregulation of miR-98 by mimic transfection protected Jurkat cells against Fas-mediated apoptosis at both mRNA and protein levels, while miR-98 inhibitor induced the completely opposite effect. Luciferase reporter assays demonstrated that miR-98 directly targeted Fas mRNA. Further, miR-98 inhibitor induced apoptosis in primary healthy CD4+ T cells through the Fas-caspase axis, while upregulation of miR-98 in SLE CD4+ T cells led to the opposite effect. The current study revealed that downregulation of miR-98 induces apoptosis by modulating the Fas-mediated apoptotic signaling pathway in SLE CD4+ T cells. These results suggest that miR-98 might serve as a potential target for SLE treatment.

Proliferation and apoptosis of human placental cells exposed to aromatic hydrocarbons.

The objective of this study is to assess the effect of elevated urinary levels of aromatic hydrocarbons (AH) on the proliferation and apoptosis of human placental trophoblast cells obtained in the course of normal pregnancy in an AH-polluted region. Tissue material was obtained for study purposes from 50 afterbirths from Płock as the study group and 50 afterbirths from Kutno as the control group. The extent and intensity of reactions were analyzed. The levels of phenol and 1-hydroxypyrene in the excreted urine of pregnant (in labor) patients were determined by gas chromatography and colorimetry. The proliferative activity of trophoblast cells was assessed using MPM-2 antibodies against phosphoprotein synthesized upon mitotic induction and Ki-67 antigen while the intensity of apoptosis in trophoblast cells was assessed using p53 and bcl-2 oncoproteins involved in apoptosis-regulating mechanisms. The immunohistochemical reactions were assessed for their extent and intensity. The levels of phenol and 1-hydroxypyrene excreted in the urine were statistically significantly higher in patients from Płock region. The proliferative activity of trophoblast cells was statistically significantly higher in the study group (p < 0.05). The activity of oncoprotein bcl-2 was significantly higher in the study group while the activity of p53 was sig¬nificantly higher in the control group. Pregnancy in an aromatic hydrocarbon-polluted environment has a significantly negative impact on placental tissue. Ad¬aptation mechanisms are induced as manifested by increased proliferative activity within the trophoblast and extensive inhibition of apoptosis in the study group.

Research Advances in Resistance to Platinum-based Chemotherapy in Lung Cancer.

Platinum-based chemotherapy is the the cornerstone of treatment of many cancers. Combinations of platinum drugs with other agents are still the mainstream therapies for non-small cell lung cancer,showing significant effectiveness in an early phase. Along with the treatment,the tumor cells can become resistant to chemotherapy drugs,which affect the efficacy and prognosis. The mechanisms of drug resistance are complicated,including abnormal expressions of membrane proteins,enhanced DNA repair functions,abnormal regulation mechanisms of apoptosis,and enhanced cellular detoxification function. In this article we summarize some of the main mechanisms of platinum resistance in lung cancer cells,with an attempt to identify new potential target analogues or inhibitors and improve the efficacies of the combined use of platinum-based drugs.

A fluorescent turn on nanoprobe for simultaneous visualization of dual-targets involved in cell apoptosis and drug screening in living cells.

Herein, a novel dual-responsive two-color fluorescent nanoprobe has been designed for the fluorescence activation imaging of cell apoptosis in living cells. The nanoprobe consists of a gold nanoparticle core functionalized with a dense layer of DNA aptamers and peptides, which shows high affinity and specific response to cytochrome c (Cyt c) and caspase-3, respectively. The formation of the aptamer-Cyt c complex and the cleavage of the specific peptide by caspase-3 can liberate the dye labelled aptamers and peptides from the surface of gold nanoparticles, and then recover their fluorescence. The turn-on and specific recognition properties of our nanoprobe allow for the sensitive and selective detection of Cyt c concentration and caspase-3 activity both in solutions and in living cells. The here proposed nanoprobe with the abilities of real-time monitoring the cell apoptosis and evaluating the apoptosis-related drug efficacy might serve as a potential interesting tool for studying the molecular mechanisms of apoptosis regulation or screening the apoptosis-based drugs.

Interleukin-17A mediates cardiomyocyte apoptosis through Stat3-iNOS pathway

Interleukin-17A, a pro-inflammatory cytokine, has a direct proapoptotic effect on cardiomyocytes. However, the specific mechanism has not been clarified. In the present study, an in-vitro model of cardiomyocyte apoptosis induced by IL-17A stimulation was employed and the roles of iNOS and Stat3 involved were investigated. Our data showed that the neonatal mouse cardiomyocytes express IL-17 receptors: IL-17RA and IL-17RC, but did not express IL-17A. Exogenous IL-17A significantly induces iNOS expression and hence the cardiomyocyte apoptosis. Moreover, IL-17A-induced cardiomyocyte apoptosis can be achieved directly via iNOS activation. We further showed that exogenous IL-17A simultaneously triggers Stat3 activation, which in turn inhibits IL-17A-induced iNOS expression in cardiomyocytes. And both ChIP and dual-luciferase results confirmed that Stat3 directly inhibits transcriptional activities of iNOS via binding to its specific promoter region. Consistent with these data, silencing of Stat3 in fact can aggravate IL-17A-triggered cardiomyocyte apoptosis. Finally, using an in vivo myocardial ischemia/reperfusion injury model, we verified that Stat3 inhibition increased iNOS expression and exacerbated cardiomyocyte apoptosis. Thus, our data strongly support the notion that Stat3 plays a compensatory anti-apoptotic role in IL-17A/iNOS-mediated cardiomyocyte apoptosis via inhibiting iNOS transcription, providing a novel molecular mechanism of apoptosis regulation and complicated interactions between IL-17A/iNOS and IL-17A/Stat3 signalings.

BOK: Oddball of the BCL-2 Family.

BOK is a BCL-2 family member whose function has been difficult to elucidate. It has been recently demonstrated that BOK is regulated by the endoplasmic reticulum associated-degradation (ERAD) pathway, can induce mitochondrial outer membrane permeabilization (MOMP), and is not regulated by other members of the BCL-2 family. These findings demonstrate a novel mechanism for regulation of apoptosis, but it remains unclear in which specific contexts this mechanism may be most essential for cell death.

PI3K/AKT Signaling Pathway Is Essential for Survival of Induced Pluripotent Stem Cells.

Apoptosis is a highly conserved biochemical mechanism which is tightly controlled in cells. It contributes to maintenance of tissue homeostasis and normally eliminates highly proliferative cells with malignant properties. Induced pluripotent stem cells (iPSCs) have recently been described with significant functional and morphological similarities to embryonic stem cells. Human iPSCs are of great hope for regenerative medicine due to their broad potential to differentiate into specialized cell types in culture. They may be useful for exploring disease mechanisms and may provide the basis for future cell-based replacement therapies. However, there is only poor insight into iPSCs cell signaling as the regulation of apoptosis. In this study, we focused our attention on the apoptotic response of Alzheimer fibroblast-derived iPSCs and two other Alzheimer free iPSCs to five biologically relevant kinase inhibitors as well as to the death ligand TRAIL. To our knowledge, we are the first to report that the relatively high basal apoptotic rate of iPSCs is strongly suppressed by the pancaspase inhibitor QVD-Oph, thus underlining the dependency on proapoptotic caspase cascades. Furthermore, wortmannin, an inhibitor of phosphoinositid-3 kinase / Akt signaling (PI3K-AKT), dramatically and rapidly induced apoptosis in iPSCs. In contrast, parental fibroblasts as well as iPSC-derived neuronal cells were not responsive. The resulting condensation and fragmentation of DNA and decrease of the membrane potential are typical features of apoptosis. Comparable effects were observed with an AKT inhibitor (MK-2206). Wortmannin resulted in disappearance of phosphorylated AKT and activation of the main effector caspase-3 in iPSCs. These results clearly demonstrate for the first time that PI3K-AKT represents a highly essential survival signaling pathway in iPSCs. The findings provide improved understanding on the underlying mechanisms of apoptosis regulation in iPSCs.