Apoptosis

The Effects of Severe Symptoms of SARS-CoV-2 Infections on the Anti/Proapoptotic Molecules: A 6-Month Cohort Study

The plausible effects of SARS-CoV-2 infection on the expression of anti/proapoptotic molecules have been suspected. This cohort study examined the expression of p53, Bcl-2, Bid, Bak, and Bax molecules, the genes associated with induction or inhibition of apoptosis, in the SARS-CoV-2-infected patients with severe and mild symptoms in an Iranian population. In this 6-month cohort study, the expression of p53, Bcl-2, Bid, Bak, and Bax molecules was evaluated at onset of diagnosis, 24 h after symptom onset, and 6 months later in the nasopharyngeal cells of SARS-CoV-2-infected hospitalized patients and outpatients in comparison with healthy controls using the real-time PCR technique. At the onset of the study, the relative expression of p53, Bcl-2, Bid, Bak, and Bax significantly increased in the SARS-CoV-2-infected hospitalized patients and decreased after 6 months. The healthy controls showed potential positive correlations among the molecules, but the patients did not show these correlations. Since SARS-CoV-2 needs host cell survival, it appears that the virus induces the expression of Bcl-2 as an antiapoptotic molecule, and the host cells upregulate the proapoptotic molecules to neutralize the effects. Dysregulation of correlation expression of the molecules among the patients proved that SARS-CoV-2 affects the expression of the molecules involved in apoptosis. SARS-CoV-2 could be considered an important factor that regulates the expression of several molecules participating in cancer pathogenesis.

Lotus leaf extract can attenuate salpingitis in laying hens by inhibiting apoptosis

This study aimed to determine whether the lotus leaf extract (LLE) had the effect of treating salpingitis in laying hens. First, the salpingitis model was established by the method of bacterial infection. Differential genes between salpingitis and healthy laying hens were identified by transcriptome sequencing, and GO and KEGG enrichment analyses were performed. Groups of treatment of antibiotics and LLE were established to verify the feasibility of the lotus leaf extract in treating salpingitis. Furthermore, the active component and pharmacological effects of LLE were identified using the UPLC-Q-TOF-MS and network pharmacology technique. At last, the mechanism of LLE treating salpingitis was further evaluated by DF-1 cells infected with bacteria. The results showed that LLE significantly reduced the levels of TLR4 and IFN-γ (P < 0.05), accelerated the levels of IgA and IgG (P < 0.05), regulated the levels of SOD and MDA (P < 0.05) in laying hens with salpingitis. A total of 1,874 differential genes were obtained according to the transcriptome sequencing. It was revealed a significant role in cell cycle and apoptosis by enrichment analysis. In addition, among the 28 components identified by UPLC-Q-TOF-MS, 20 components acted on 58 genes, including CDK1, BIRC5, and CA2 for treating salpingitis. After bacterial infection, cells were damaged and unable to complete the normal progression of the cell cycle, leading to cell cycle arrest and further apoptosis formation. However, with the intervention of LLE, bacterial infection was resisted. The cells proliferation was extensively restored, and the expression of NO was increased. The addition of LLE significantly decreased cell apoptosis. The G1 phase increased, the S phase and the G2 phase decreased in the model group; after the intervention of LLE, the G1 phase gradually returned to the average level, and G2 and S phases increased. The mRNA expression levels of BIRC5, CDK1, and CA2 were consistent with the predicted results in network pharmacology. At the same time, the mRNA expression levels of Caspase-3 and Caspase-7 were reduced after added with LLE. The mRNA expression levels of TNF-α, TRADD, FADD, Caspase-8, Caspase-10, and Caspase-9 (P < 0.05), which would inhibit death receptor activation and decrease the apoptotic cascade, were upregulated after bacterial infection. However, the results in LLE groups were downregulated (P < 0.05). Meanwhile, the mRNA expression levels of BCL-2 in LLE groups were increased significantly compared with it in model group (P < 0.05). Notably, LLE administration inhibited apoptosis and regulated the cell cycle distribution in the salpingitis induced by bacterial infection. These results indicated that the LLE attenuated bacterial-induced salpingitis by modulating apoptosis and immune function in laying hens.

Cytotoxic Effects of Castalin Nanoparticles Against Osteosarcoma

The size-dependent bioactivities of castalin were analyzed by comparing the cytotoxic effects of native castalin and castalin nanoparticles on osteosarcoma in vitro and in vivo. In vitro experiments indicated that castalin nanoparticles induced apoptosis of an osteosarcoma cell line more efficiently than native castalin. The more potent effects of castalin nanoparticles, relative to native castalin, were confirmed in vivo using a xenograft osteosarcoma model. Caco-2 cell transport studies showed that permeation of castalin nanoparticles was higher than native castalin. The higher bioactivity and superior bioavailability of castalin nanoparticles could potentially be utilised to develop novel therapies for osteosarcoma.

Molecular mechanism of shikonin inhibiting tumor growth and potential application in cancer treatment

Shikonin is one of the major bioactive components of Lithospermum erythrorhizon. It has a good killing effect in a variety of tumor cells. Its antitumor effect involves multiple targets and pathways and has received extensive attention and study in recent years. In this review, we systematically review recent progress in determining the antitumor mechanism of shikonin and its derivatives, specifically their induction of reactive oxygen species production, inhibition of EGFR and PI3K/AKT signaling pathway activation, inhibition of angiogenesis and induction of apoptosis and necroptosis. We also discuss the application of nanoparticles loaded with shikonin in the targeted therapy of various cancers. Finally, we suggest new strategies for the clinical application of shikonin and its derivatives.

Conditional ERK3 overexpression cooperates with PTEN deletion to promote lung adenocarcinoma formation in mice

ERK3, officially known as mitogen‐activated protein kinase 6 (MAPK6), is a poorly studied mitogen‐activated protein kinase (MAPK). Recent studies have revealed the upregulation of ERK3 expression in cancer and suggest an important role for ERK3 in promoting cancer cell growth and invasion in some cancers, in particular lung cancer. However, it is unknown whether ERK3 plays a role in spontaneous tumorigenesis in vivo. To determine the role of ERK3 in lung tumorigenesis, we created a conditional ERK3 transgenic mouse line in which ERK3 transgene expression is controlled by Cre recombinase. By crossing these transgenic mice with a mouse line harboring a lung tissue–specific Cre recombinase transgene driven by a club cell secretory protein gene promoter (CCSP‐iCre), we have found that conditional ERK3 overexpression cooperates with phosphatase and tensin homolog (PTEN) deletion to induce the formation of lung adenocarcinomas (LUADs). Mechanistically, ERK3 overexpression stimulates activating phosphorylations of erb‐b2 receptor tyrosine kinases 2 and 3 (ERBB2 and ERBB3) by upregulating Sp1 transcription factor (SP1)–mediated gene transcription of neuregulin 1 (NRG1), a potent ligand for ERBB2/ERBB3. Our study has revealed a bona fide tumor‐promoting role for ERK3 using genetically engineered mouse models. Together with previous findings showing the roles of ERK3 in cultured cells and in a xenograft lung tumor model, our findings corroborate that ERK3 acts as an oncoprotein in promoting LUAD development and progression.

TRAIL-conjugated silver nanoparticles sensitize glioblastoma cells to TRAIL by regulating CHK1 in the DNA repair pathway

OBJECTIVES

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) selectively triggers apoptosis in cancer cells, but not in normal cells. Resistance of glioblastoma cells to TRAIL is a major obstacle for successful clinical treatment of TRAIL. Thus, there is an essential requirement for novel approaches to sensitize TRAIL resistance. Silver nanoparticles (AgNPs) are one of the most promising nanomaterials that show immense antitumor potential via targeting various cellular and molecular processes; however, the effects of AgNPs on TRAIL sensitivity in cancer cells remain unclear. Therefore, we hypothesized that TRAIL-conjugated AgNPs (TRAIL-AgNPs) can overcome TRAIL resistance through inducing death receptor activation in glioblastoma cells, but not normal cells.

METHODS

In this study, the therapeutic effect of TRAIL-AgNPs is investigated by analyzing the cell viability, caspase activity, and CHK1 gene expression in T98 G TRAIL-Sensitive (TS) and T98 G TRAIL-Resistant (TR) glioblastoma cells.

RESULTS

It is found that TRAIL-AgNPs are more toxic compared to TRAIL and AgNPs treatments alone on TR cells. While TRAIL and AgNPs alone do not enhance the caspase activity, conjugation of TRAIL to AgNPs increases the caspase activity in TR cells. Moreover, the TRAIL-AgNPs-treated TR cells show less CHK1 expression compared to the TRAIL treatment.

CONCLUSION

These results suggest that TRAIL sensitivity of TR cells can be enhanced by conjugation of TRAIL with AgNPs, which would be a novel therapeutic approach to sensitize TRAIL resistance.

Geranium thunbergii extract-induced G1 phase cell cycle arrest and apoptosis in gastric cancer cells

Geranium thunbergii is a traditional East Asian medicine for stomach diseases including dysentery and stomach ulcers in East Asia and has been reported to possess biological activity. The benefits of G. thunbergii in gastric cancer are unknown. In this study, we demonstrate that G. thunbergii extract suppresses proliferation and induces death and G1/S cell cycle arrest of gastric cancer cells. Proliferation was significantly inhibited in a time- and dose-dependent manner. Cell cycle arrest was associated with significant decreases in CDK4/cyclinD1 complex and CDK2/cyclinE complex genes expression. In addition, the protein expression of caspase-3 was decreased and that of activated poly (ADP-ribose) polymerase (PARP) was increased, which indicated apoptosis. The expressions of the Bax and Bcl-2, which are apoptosis related proteins, were upregulated and down-regulated, respectively. The results indicate that G. thunbergii extract can inhibit proliferation and induce both G/S cell cycle arrest and apoptosis of gastric cancer cells. Also, the induction of apoptosis involved the intrinsic pathways of the cells. Take the results, we suggest that G. thunbergii extract has anti-gastric cancer activity and may be a potential therapeutic candidate for gastric cancer.

Recent progress regarding kaempferol for the treatment of various diseases

Kaempferol, also known as kaempferol-3 or kaempferide, is a flavonoid compound that naturally occurs in tea, as well as numerous common vegetables and fruits, including beans, broccoli, cabbage, gooseberries, grapes, kale, strawberries, tomatoes, citrus fruits, brussel sprouts, apples and grapefruit. The present review mainly summarizes the application of kaempferol in treating diseases and the underlying mechanisms that are currently being studied. Due to its anti-inflammatory properties, it may be used to treat numerous acute and chronic inflammation-induced diseases, including intervertebral disc degeneration and colitis, as well as post-menopausal bone loss and acute lung injury. In addition, it has beneficial effects against cancer, liver injury, obesity and diabetes, inhibits vascular endothelial inflammation, protects the cranial nerve and heart function, and may be used for treating fibroproliferative disorders, including hypertrophic scar.

Central Role of Cell Cycle Regulation in the Antitumoral Action of Ocoxin

Nutritional supplements which include natural antitumoral compounds could represent safe and efficient additives for cancer patients. One such nutritional supplement, Ocoxin Oral solution (OOS), is a composite formulation that contains several antioxidants and exhibits antitumoral properties in several in vitro and in vivo tumor conditions. Here, we performed a functional genomic analysis to uncover the mechanism of the antitumoral action of OOS. Using in vivo models of acute myelogenous leukemia (AML, HEL cells, representative of a liquid tumor) and small-cell lung cancer (GLC-8, representative of a solid tumor), we showed that OOS treatment altered the transcriptome of xenografted tumors created by subcutaneously implanting these cells. Functional transcriptomic studies pointed to a cell cycle deregulation after OOS treatment. The main pathway responsible for this deregulation was the E2F-TFDP route, which was affected at different points. The alterations ultimately led to a decrease in pathway activation. Moreover, when OOS-deregulated genes in the AML context were analyzed in patient samples, a clear correlation with their levels and prognosis was observed. Together, these data led us to suggest that the antitumoral effect of OOS is due to blockade of cell cycle progression mainly caused by the action of OOS on the E2F-TFDP pathway.

Effects of 12C6+ heavy ion beam irradiation on the p53 signaling pathway in HepG2 liver cancer cells

The heavy ion beam is considered to be the ideal source for radiotherapy. The p53 tumor suppressor gene senses DNA damage and transducts intracellular apoptosis signals. Previous reports showed that the heavy ion beam can trigger complex forms of damage to cellular DNA, leading to cell cycle arrest and apoptosis of HepG2 human liver cancer cells; however, the mechanisms remains unclear fully. In order to explore whether the intrinsic or extrinsic pathway participates this process, HepG2 cells were treated with 12C6+ HIB irradiation at doses of 0 (control), 1, 2, 4, and 6 Gy with various methods employed to understand relevant mechanisms, such as detection of apoptosis, cell cycle, and Fas expression by flow cytometry, analysis of apoptotic morphology by electron microscopy and laser scanning confocal microscopy, and screening differentially expressed genes relating to p53 signaling pathway by PCR-array assay following with any genes confirmed by western blot analysis. This study showed that 12C6+ heavy ion beam irradiation at a dose of 6 Gy leads to endogenous DNA double-strand damage, G2/M cell cycle arrest, and apoptosis of human HepG2 cells via synergistic effect of the extrinsic and intrinsic pathways. Differentially expressed genes in the p53 signaling pathway related to DNA damage repair, apoptosis, cycle regulation, metastasis, deterioration and radioresistance were also discovered. Consequently, the expressions of Fas, TP53BP2, TP53AIP1, and CASP9 were confirmed upregulated after 12C6+ HIB irradiation treatment. In conclusion, this study demonstrated the mechanisms of inhibition and apoptosis induced by 12C6+ heavy ion beam irradiation on HepG2 cancer cells is mediated by initiation of the biological function of p53 signaling pathway including extrinsic and intrinsic apoptosis pathway.

Boehmenan, a Lignan From the Chinese Medicinal Plant Clematis armandii, Inhibits A431 Cell Growth via Blocking p70S6/S6 Kinase Pathway

Previously, we have shown that boehmenan, a natural product isolated from the dried stem of Caulis clematidis armandii, exhibits various biological activities. The current study investigated the effects of boehmenan on the growth of human epidermoid carcinoma A431 cells. Cell viability and 50% inhibiting concentration (IC₅₀) were assessed by CellTiter-Glo luminescent cell viability assay. Cell cycle arrest was measured by flow cytometry. Intracellular reactive oxygen species production and mitochondrial membrane potential (ΔΨ_m) collapse were analyzed by a fluorescence spectrophotometer. The activation of epidermal growth factor receptor signaling pathway was evaluated by Western blot. The results showed that boehmenan significantly inhibited the growth of A431 cells (IC₅₀ = 1.6 µM) in a concentration- and time-dependent manner. This compound also blocked cell cycle progression at G2/M phase and modulated mitochondrial apoptosis-related proteins, as evidenced by upregulating p21, cleaved caspase-3, and cleaved poly (ADP-ribose) polymerase protein levels and by downregulating Bcl-2, pro-caspase-9 levels. In addition, boehmenan also markedly induced intracellular reactive oxygen species production and ΔΨ_m depolarization in a concentration-dependent manner. Furthermore, boehmenan-attenuated epidermal growth factor mediated the phosphorylation of signal transducer and activator of transcription 3 (STAT3), p70 ribosomal protein S6 kinase (p70S6)/S6 in a concentration-dependent manner. Taken together, our results suggest that boehmenan-mediated antiproliferative property in A431 cells was mediated partially by modulation of mitochondrial function and inhibition of STAT3 and p70S6 signal pathways.

Unraveling the Pathogenesis of MDS: The NLRP3 Inflammasome and Pyroptosis Drive the MDS Phenotype

Myelodysplastic syndromes (MDS) are characterized by bone marrow cytological dysplasia and ineffective hematopoiesis in the setting of recurrent somatic gene mutations and chromosomal abnormalities. The underlying pathogenic mechanisms that drive a common clinical phenotype from a diverse array of genetic abnormalities have only recently begun to emerge. Accumulating evidence has highlighted the integral role of the innate immune system in upregulating inflammatory cytokines via NF-κB activation in the pathogenesis of MDS. Recent investigations implicate activation of the NLRP3 inflammasome in hematopoietic stem/progenitor cells as a critical convergence signal in MDS with consequent clonal expansion and pyroptotic cell death though caspase-1 maturation. Specifically, the alarmin S100A9 and/or founder gene mutations trigger pyroptosis through the generation of reactive oxygen species leading to assembly and activation of the redox-sensitive NLRP3 inflammasome and β–catenin, assuring propagation of the MDS clone. More importantly, targeted inhibition of varied steps in this pathway restore effective hematopoiesis. Together, delineation of the role of pyroptosis in the clinical phenotype of MDS patients has identified novel therapeutic strategies that offer significant promise in the treatment of MDS.

Significance of apoptosis related proteins on malignant transformation of ovarian tumors: A comparison between Bcl-2/Bax ratio and p53 immunoreactivity

In this study, we compared the immunoreactivities of Bcl-2, Bax and p53 proteins in ovarian tumors and related the immunohistochemical findings to the histological type of the tumors. Formalin-fixed, paraffin wax-embedded tissue sections from 40 patients who had serous-mucinous borderline tumors and serous-mucinous adenocarcinoma of the ovary (n=10 each) were stained with hematoxylin-eosin (H&E). After histopathological examination, serial sections were stained immunohistochemically with primary antibodies to Bcl-2, Bax and p53 using an avidin-biotin-peroxidase method. A semi-quantitative grading system was used to compare the immunohistochemical staining intensities. The nuclear DNA fragmentation of apoptosis was determined using TUNEL method. As a result of immunohistochemical staining, increased immunoreactivity of Bcl-2 was observed in adenocarcinomas when compared to borderline tumors (P<0.001). Strong immunoreactivity of Bcl-2 and mild immunoreactivities of Bax and p53 were detected in ovarian adenocarcinomas. There were no significant statistical differences in the immunoreactivity of Bax among the histological type of ovarian tumors. Whereas a balance was observed between the immunoreactivities of Bcl-2 and Bax in the borderline cases, and this balance was strongly changed toward the anti-apoptotic Bcl-2 protein in patients with adenocarcinoma. TUNEL staining of sections indicated apoptotic cells in the serous borderline tumors were about 8-fold higher than in the serous adenocarcinoma. The results of this study on apoptosis-related factors might help to develop novel protective and therapeutic approaches, such as isoflavonoids and isothiocyanates, which were associated with decreased Bcl-2/Bax ratio, against the malignant epithelial ovarian tumors.

Transfection of poly(I:C) can induce reactive oxygen species-triggered apoptosis and interferon-β-mediated growth arrest in human renal cell carcinoma cells via innate adjuvant receptors and the 2-5A system

Background

Synthetic double-stranded RNA poly(I:C) is a useful immune adjuvant and exhibits direct antitumor effects against several types of cancers. In this study, we elucidated the mechanisms underlying the effects induced in poly(I:C)-transfected human renal cell carcinoma (RCC) cells.

Results

In contrast to the lack of an effect of adding poly(I:C), poly(I:C) transfection drastically decreased RCC cell viability. Poly(I:C) transfection induced reactive oxygen species (ROS)-dependent apoptosis in RCC cells and decreased the mitochondrial membrane potential (ΔΨm). Treatment with N-acetyl-l-cysteine (NAC), a ROS scavenger, suppressed apoptosis and restored the ΔΨm. Although the levels of phosphorylated γH2A.X, an indicator of DNA damage, increased in poly(I:C)-transfected RCC cells, NAC treatment decreased their levels, suggesting ROS-mediated DNA damage. Furthermore, poly(I:C) transfection increased the levels of phosphorylated p53, NOXA, and tBid. Immunoblots and assays with a panel of caspase inhibitors revealed that poly(I:C) transfection-induced apoptosis was dependent on caspase-8 and -9, as well as caspase-2. Alternatively, poly(I:C) transfection increased mRNA expression of interferon (IFN)-β, and treatment with IFN-β suppressed growth of RCC cells without apoptosis. In addition, cyclinD1 and c-Myc expression decreased in poly(I:C)-transfected RCC cells. Moreover, RNA interference experiments revealed that poly(I:C) transfection exerted apoptotic effects on RCC cells through innate adjuvant receptors and the 2-5A system, the latter of which induces apoptosis in virus-infected cells.

Conclusions

These results suggest that poly(I:C) transfection induced two types of effects against RCC cells such as apoptosis, as a result of ROS-mediated DNA damage, and IFN-β-mediated growth arrest, both of which were exerted via innate adjuvant receptors and the 2-5A system.

Electronic supplementary material

The online version of this article (doi:10.1186/1476-4598-13-217) contains supplementary material, which is available to authorized users.

The role of Bcl-2 family proteins in pulmonary fibrosis

Pulmonary fibrosis is characterized by epithelial injury, abnormal tissue repair, fibroproliferation and loss of pulmonary function as a result of a complex interaction of multiple cellular and molecular processes. There is accumulating evidence in support of a role for apoptosis in the pathogenesis of interstitial lung diseases. The Bcl-2 (B-cell lymphoma-2) family of proteins, which consists of antiapoptotic and pro-apoptotic members, is a critical regulator for apoptosis and development of pulmonary fibrosis. The association between Bcl-2 family members and various pathways and mediators has been also described in the pulmonary fibrosis. This article reviews the recent advances regarding the roles of Bcl-2 family as the apoptosis-regulatory factors in pulmonary fibrosis from human tissue studies, animal models, ex vivo and in vitro studies. Further understanding of apoptosis signaling regulation through Bcl-2 family proteins in the lung tissue may lead to better design of new therapeutic interventions for pulmonary fibrosis.

Shikonin time-dependently induced necrosis or apoptosis in gastric cancer cells via generation of reactive oxygen species

The effects of shikonin on gastric cancer cells were investigated in this study. Exposure to shikonin reduced the viability of gastric cancer cells in a time- and dose-dependent manner. However, apoptosis was not observed in gastric cancer cell treatment with different concentrations of shikonin for 6h. By contrast, treatment with shikonin for 24h significantly induced apoptosis, as evidenced by the results of TUNEL assay and flow cytometry analysis in proportion to the concentration. Disruption of the mitochondrial membrane potential was observed in gastric cancer cells that were treated with shikonin for 6 and 24h. Pretreatment with necrostatin-1 recovered cell death and mitochondrial membrane potential in the 6h shikonin treatment, but not in the 24h shikonin treatment. Western blot results reveal enhanced p38 phosphorylation, downregulated AKT phosphorylation, and increased caspase3 and PARP cleavage in cells that were treated with shikonin for 24h, but not in cells treated for 6h. Shikonin also triggered reactive oxygen species (ROS) generation both in the 6 and 24h treatments. Pretreatment with N-acetylcysteine blocked shikonin-induced cell death. In summary, our findings suggest that shikonin, which may function as a promising agent in the treatment of gastric cancers, sequentially triggered necrosis or apoptosis through ROS generation in gastric cancer cells.

Induction of apoptosis in cancer cell lines by the Red Sea brine pool bacterial extracts

BACKGROUND

Marine microorganisms are considered to be an important source of bioactive molecules against various diseases and have great potential to increase the number of lead molecules in clinical trials. Progress in novel microbial culturing techniques as well as greater accessibility to unique oceanic habitats has placed the marine environment as a new frontier in the field of natural product drug discovery.

METHODS

A total of 24 microbial extracts from deep-sea brine pools in the Red Sea have been evaluated for their anticancer potential against three human cancer cell lines. Downstream analysis of these six most potent extracts was done using various biological assays, such as Caspase-3/7 activity, mitochondrial membrane potential (MMP), PARP-1 cleavage and expression of γH2Ax, Caspase-8 and -9 using western blotting.

RESULTS

In general, most of the microbial extracts were found to be cytotoxic against one or more cancer cell lines with cell line specific activities. Out of the 13 most active microbial extracts, six extracts were able to induce significantly higher apoptosis (>70%) in cancer cells. Mechanism level studies revealed that extracts from Chromohalobacter salexigens (P3-86A and P3-86B(2)) followed the sequence of events of apoptotic pathway involving MMP disruption, caspase-3/7 activity, caspase-8 cleavage, PARP-1 cleavage and Phosphatidylserine (PS) exposure, whereas another Chromohalobacter salexigens extract (K30) induced caspase-9 mediated apoptosis. The extracts from Halomonas meridiana (P3-37B), Chromohalobacter israelensis (K18) and Idiomarina loihiensis (P3-37C) were unable to induce any change in MMP in HeLa cancer cells, and thus suggested mitochondria-independent apoptosis induction. However, further detection of a PARP-1 cleavage product, and the observed changes in caspase-8 and -9 suggested the involvement of caspase-mediated apoptotic pathways.

CONCLUSION

Altogether, the study offers novel findings regarding the anticancer potential of several halophilic bacterial species inhabiting the Red Sea (at the depth of 1500-2500 m), which constitute valuable candidates for further isolation and characterization of bioactive molecules.

Cytotoxic effects of fucoidan nanoparticles against osteosarcoma

In this study, we analyzed the size-dependent bioactivities of fucoidan by comparing the cytotoxic effects of native fucoidan and fucoidan lipid nanoparticles on osteosarcoma in vitro and in vivo. In vitro experiments indicated that nanoparticle fucoidan induced apoptosis of an osteosarcoma cell line more efficiently than native fucoidan. The more potent effects of nanoparticle fucoidan, relative to native fucoidan, were confirmed in vivo using a xenograft osteosarcoma model. Caco-2 cell transport studies showed that permeation of nanoparticle fucoidan was higher than native fucoidan. The higher bioactivity and superior bioavailability of nanoparticle fucoidan could potentially be utilized to develop novel therapies for osteosarcoma.

Expressions and localizations of Bax/Bcl-2 proteins during metamorphosis of Pelophylax ridibundus

Bcl-2 and Bax proteins are expressed in cells of the tails of Pelophylax ridibundus larvae. We investigated the levels of these proteins in tails undergoing apoptosis. Apoptotic cells were observed in the epidermis, muscle and notochord of tails of different lengths. The apoptotic cells in epidermis exhibited the typical features of apoptosis. Amorphous masses and irregularities in striated muscle tissue undergoing apoptosis and apoptotic remnants in the notochord also were observed. In general, Bax staining in the epidermis, subepidermal fibroblast layer, muscle and notochord cells increased, while Bcl-2 staining decreased as the tail regressed. Our results suggest that during tail regression due to metamorphosis, Bcl-2 and Bax proteins play key roles in the apoptosis of tail epidermis, subepidermal fibroblast layer, muscle and notochord cells.

Juglone, isolated from Juglans mandshurica Maxim, induces apoptosis via down-regulation of AR expression in human prostate cancer LNCaP cells

Juglone is a natural compound which has been isolated from Juglans mandshurica Maxim. Recent studies have shown that juglone had various pharmacological effects such as anti-viral, anti-bacterial and anti-cancer. However, its anti-cancer activity on human prostate cancer LNCaP cell has not been examined. Thus, the current study was designed to elucidate the molecular mechanism of apoptosis induced by juglone in androgen-sensitive prostate cancer LNCaP cells. MTT assay was performed to examine the anti-proliferative effect of juglone. Occurrence of apoptosis was detected by Hoechst 33342 staining and flow cytometry in LNCaP cells treated with juglone for 24h. The result shown that juglone inhibited the growth of LNCaP cells in a dose-dependent manner. Morphological changes of apoptotic body formation after juglone treatment were observed by Hoechst 33342 staining. This apoptotic induction was associated with loss of mitochondrial membrane potential, and caspase-3, -9 activation. Moreover, we found that juglone significantly inhibited the expression levels of androgen receptor (AR) and prostate-specific antigen (PSA) in a dose-dependent manner, as well as abrogated up-regulation of AR and PSA genes with and/or without dihydrotestosterone (DHT). Take together, our results demonstrated that juglone might induce the apoptosis in LNCaP cell via down-regulation of AR expression. Therefore, our results indicated that juglone may be a potential candidate of drug for androgen-sensitive prostate cancer.

Inhibition of tumor growth in vitro and in vivo by fucoxanthin against melanoma B16F10 cells

The present study was designed to evaluate the molecular mechanisms of fucoxanthin against melanoma cell lines (B16F10 cells). Fucoxanthin reduced the proliferation of B16F10 cells in a dose-dependent manner accompanied by the induction of cell cycle arrest during the G(0)/G(1) phase and apoptosis. Fucoxanthin-induced G(0)/G(1) arrest was associated with a marked decrease in the protein expressions of phosphorylated-Rb (retinoblastoma protein), cyclin D (1 and 2) and cyclin-dependent kinase (CDK) 4 and up-regulation of the protein levels of p15(INK4B) and p27(Kip1). Fucoxanthin-induced apoptosis was accompanied with the down-regulation of the protein levels of Bcl-xL, an inhibitor of apoptosis proteins (IAPs), resulting in a sequential activation of caspase-9, caspase-3, and PARP. Furthermore, the anti-tumor effect of fucoxanthin was assessed in vivo in Balb/c mice. Intraperitoneal administration of fucoxanthin significantly inhibited the growth of tumor mass in B16F10 cells implanted mice.

A controlled case study of the relationship between environmental risk factors and apoptotic gene polymorphism and lumbar disc herniation

To explore the etiologic role of apoptosis-related genes, environmental risk factors, and their interaction in the occurrence of lumbar disk herniation (LDH), a controlled case study was performed with 128 LDH patients and 132 age- and sex-matched controls. Matrix-assisted laser desorption/ionization, time-of-flight mass spectrometry assay was used to analyze the genotype of nine polymorphism sites in three genes, including Fas -1377G/A rs2234767, Fas -670G/A rs1800682, Fas rs2147420, Fas rs2296603, Fas rs7901656, Fas rs1571019, Fas ligand (FasL) -844C/T rs763110, caspase 9 (CASP9) -1263A>G rs4645978, and CASP9 -712C>T rs4645981. The patients and controls showed similar age and sex, but had significant differences in lumbar load, bed type, amateur sports, and leisure activities (P < 0.05). The correlation analysis revealed that polymorphism of FasL -844C/T (rs763110) and CASP9 -1263A>G (rs4645978) had a significant correlation with LDH, indicating that the genotypes of FasL -844C/T TT and CASP9 -1263A>G GG are probably high-risk genotypes for LDH. The results of environment-gene interaction analysis revealed that, in LDH, the interaction of the FasL -844TT genotype and level III to IV lumbar load was consistent with the ultramultiplying model, and the interaction of the CASP9 rs4645978 GG genotype and level III to IV lumbar load was consistent with the submultiplicative model. Therefore, the risk of LDH was determined by both environmental and genetic risk factors, and the mechanisms of interactions between different genotypes and environmental factors also differed.

FG020326 sensitized multidrug resistant cancer cells to docetaxel-mediated apoptosis via enhancement of caspases activation

Apoptotic resistance is the main obstacle for treating cancer patients with chemotherapeutic drugs. Multidrug resistance (MDR) is often characterized by the expression of P-glycoprotein (P-gp), a 170-KD ATP-dependent drug efflux protein. Functional P-gp can confer resistance to activate caspase-8 and -3 dependent apoptosis induced by a range of different stimuli, including tumor necrosis and chemotherapeutic drugs such as docetaxel and vincristine. We demonstrated here that comparison of sensitive KB cells, P-gp positive (P-gp^+ve) KBv200 cells were extremely resistant to apoptosis induced by docetaxel. FG020326, a pharmacological inhibitor of P-gp function, could enhance concentration-dependently the effect of docetaxel on cell apoptosis and sensitize caspase-8, -9 and -3 activation in P-gp overexpressing KBv200 cells, but not in KB cells. Therefore, the enhancement of caspase-8, -9 and -3 activation induced by docetaxel may be one of the key mechanisms of the reversal of P-gp mediated docetaxel resistance by FG020326.

Antimicrobial, antiproliferative and proapoptotic activities of extract, fractions and isolated compounds from the stem of Erythroxylum caatingae plowman

In the study, we have examined the antitumor and antimicrobial activities of the methanol extract, the fractions, a fraction of total alkaloids and two alkaloids isolated from the stem of Erythroxylum caatingae Plowman. All test fractions, except the hexane fractions, showed antimicrobial activity on gram-positive bacteria and fungi. The acetate: methanol (95:5), acetate, chloroform and hexane fractions show the highest cytotoxicity activity against the NCI-H292, HEp-2 and K562 cell lines using MTT. The absence of hemolysis in the erythrocytes of mice was observed in these fractions and 6β-Benzoyloxy-3α-(3,4,5- trimethoxybenzoyloxy) tropane (catuabine B). Staining with Annexin V-FITC and JC-1 was used to verify the mechanism of action of the compounds of E. caatingae that showed cytotoxicity less than 30 μg/mL in leukemic cells. After 48 h of incubation, we observed that the acetate: methanol (95:5), acetate, and chloroform fractions, as well as the catuabine B, increased in the number of cells in early apoptosis, from 53.0 to 74.8%. An analysis of the potential of the mitochondrial membrane by incorporation of JC-1 showed that most cells during incubation of the acetate: methanol (95:5) and acetate fractions (63.85 and 59.2%) were stained, suggesting the involvement of an intrinsic pathway of apoptosis.

Kaempferol-3-O-rhamnoside isolated from the leaves of Schima wallichii Korth. inhibits MCF-7 breast cancer cell proliferation through activation of the caspase cascade pathway

Plants consumed by non-human primates represent potential drug sources for human disease management. In this study, we isolated kaempferol-3-O-rhamnoside as an active compound from the leaves of Schima wallichii Korth., a plant commonly consumed by non-human primates. Its anti-cancer activities, including its ability to induce apoptotic mechanisms, were investigated in MCF-7 breast cancer cells. Results showed that in MCF-7 cells, kaempferol-3-O-rhamnoside inhibits cell proliferation in a dose-dependent manner and promotes apoptosis via the activation of the caspase signaling cascade, which includes caspase-9, caspase-3 and PARP. Our results provide a basis for further exploration of kaempferol-3-O-rhamnoside as an active compound for potential anti-cancer therapeutics.

Testosterone-induced hypertrophy, fibrosis and apoptosis of cardiac cells--an ultrastructural and immunohistochemical study

Background

Androgen abuse is an increasing problem amongst professional and amateur athletes. Moreover, testosterone, apart from its widely accepted indications, is used for a variety of other indications such as aging and ischemia. Its actions are mainly attributed to a specific genomic mechanism through the androgen receptor, but emerging evidence reveals non-genomic effects as well. The use of androgens has been linked with several adverse effects. The purpose of this study was to examine the effects of testosterone on the morphology and the ultrastructure of the myocardium and to investigate the possible role of apoptosis.

Material/Methods

We used 12 adult male Wistar rats, separated into 2 groups. Group A consisted of 6 rats that were administered high doses of testosterone enanthate, while group B consisted of 6 male Wistar rats that received placebo (normal saline) intramuscularly. After the last day of treatment, all rats were anesthetized and sacrificed, and the hearts were removed and processed for optical and electron microscopy and immunohistochemical detection of caspase-3, an apoptosis marker.

Results

We found significant myocardial hypertrophy along with abundant ultrastructural alterations. The immunohistochemical staining of the myocardial cells for caspase-3 was positive in group A (experimental group), which is interpreted as an activation of apoptosis by testosterone treatment.

Conclusions

Testosterone abuse has serious adverse effects, including myocardial hypertrophy, myocardial fibrosis and activation of apoptosis. These findings need to be taken into account whenever androgens are prescribed to improve performance or as hormone therapy.

Induction of Fas-mediated extrinsic apoptosis, p21WAF1-related G2/M cell cycle arrest and ROS generation by costunolide in estrogen receptor-negative breast cancer cells, MDA-MB-231

Costunolide (C(15)H(20)O(2)) is a sesquiterpene lactone that was isolated from many herbal medicines and it has diverse effects according to previous reports. However, the anti-cancer effects and the mechanism of actions are still unknown in breast cancer. In this study, we first observed that costunolide inhibits cell growth in a dose-and time-dependent manner. To examine the mechanism by which costunolide inhibits cell growth, we checked the effect of costunolide on apoptosis and the cell cycle. Costunolide induced apoptosis through the extrinsic pathway, including the activation of Fas, caspase-8, caspase-3, and degradation of PARP. However, did not have the same effect on the intrinsic pathway as revealed by analysis of mitochondrial membrane potential (Δψm) with JC-1 dye and expression of Bcl2 and Bax proteins level. Furthermore, costunolide induced cell cycle arrest in the G2/M phase via decrease in Cdc2, cyclin B1 and increase in p21WAF1 expression, independent of p53 pathway in p53-mutant MDA-MB-231 cells and increases Cdc2-p21WAF1 binding. In addition, costunolide had a slight induced effect on ROS generation. Among the mechanisms of p21WAF1 induction examined, costunolide-induced increase in p21WAF1 expression was related with protein stability and ROS generation. Through this study we confirm that costunolide induces G2/M cell cycle arrest and apoptotic cell death via extrinsic pathway in MDA-MB-231 cells suggesting that it could be a promising anticancer drug especially for ER-negative breast cancer.

Hydrocinchonine, cinchonine, and quinidine potentiate paclitaxel-induced cytotoxicity and apoptosis via multidrug resistance reversal in MES-SA/DX5 uterine sarcoma cells

Multidrug resistance (MDR) is one of important issues to cause the chemotherapy failure against cancers including gynecological malignancies. Despite some MDR reversal evidences of natural compounds including quinidine and cinchonine, there are no reports on MDR reversal activity of hydrocinchonine with its analogues quinidine and cinchonine especially in uterine sarcoma cells. Thus, in the current study, we comparatively investigated the potent efficacy of hydrocinchonine and its analogues quinidine and cinchonine as MDR-reversal agents for combined therapy with antitumor agent paclitaxel (TAX). Hydrocinchonine, cinchonine, and quinidine significantly increased the cytotoxicity of TAX in P-glycoprotein (gp)-positive MES-SA/DX5, but not in the P-gp-negative MES-SA cells at nontoxic concentrations by 3-(4,5-dimethylthiazol-2-yl)-2,5--diphenyltetrazolium bromide (MTT) assay. Rhodamine assay also revealed that hydrocinchonine, cinchonine, and quinidine effectively enhanced the accumulation of a P-gp substrate, rhodamine in TAX-treated MES-SA/DX5 cells compared with TAX-treated control. In addition, hydrocinchonine, cinchonine, and quinidine effectively cleaved poly (ADP-ribose) polymerase (PARP), activated caspase-3, and downregulated P-gp expression as well as increased sub-G1 apoptotic portion in TAX-treated MES-SA/DX5 cells. Taken together, hydrocinchonine exerted MDR reversal activity and synergistic apoptotic effect with TAX in MES-SA/DX5 cells almost comparable with quinidine and cinchonine as a potent MDR-reversal and combined therapy agent with TAX.

Melatonin promotes puromycin-induced apoptosis with activation of caspase-3 and 5'-adenosine monophosphate-activated kinase-alpha in human leukemia HL-60 cells

Melatonin, a naturally occurring molecule, is produced by the pineal gland in a circadian manner to regulate biologic rhythms in humans. Recent studies report that melatonin may be an attractive candidate as an anticancer agent or for combined therapy because of its antioxidant, oncostatic and immunoregulatory activities. In this study, the potentiating effect of melatonin was evaluated on the apoptosis induced by puromycin as an anticancer drug in acute promyelocytic leukemia HL-60 cells. Melatonin did not show significant cytotoxicity against HL-60 cells compared to puromycin. However, melatonin significantly augmented the cytotoxicity of puromycin. Consistently, combined treatment of melatonin and puromycin reduced the expression of anti-apoptotic proteins, such as bcl-2 and bcl-x(L) , and also induced caspase-3 activation and poly (ADP-ribose) polymerase (PARP) cleavage compared to puromycin treatment alone. Furthermore, cell cycle analysis revealed that melatonin promoted puromycin-induced apoptosis by increasing the sub-G1 population, but suppressing G2/M arrest in HL-60 cells. Interestingly, melatonin activated the phosphorylation of 5'-adenosine monophosphate-activated kinase (AMPK) in combination with puromycin. Taken together, our results suggest that melatonin potentiates puromycin-induced apoptosis with caspase-3 and AMPK activation in HL-60 cells, and thus, melatonin treatment can be effectively applied to leukemia treatment as a potential sensitizer for chemotherapeutic agents.

Anti-tumor effects of dihydroartemisinin on human osteosarcoma

Dihydroartemisinin (DHA) exhibits antitumor activity against a wide spectrum of cancer cells. However, whether DHA has anti-tumor effect on human osteosarcoma cells remains unknown. This study aims to investigate the anti-tumor activity of DHA and the underlying mechanisms in human osteosarcoma cell lines with different p53 mutation statuses. Four human osteosarcoma cell lines were treated with different concentrations of DHA. Then, cell proliferation was determined by the CCK-8 viability assay; apoptosis and cell cycle progression were evaluated by flow cytometry; protein expression was analyzed by western blot assay; and NF-kB activity was examined by luciferase assay. The results demonstrated that DHA treatment could inhibit the proliferation of four osteosarcoma cell lines in a dose-dependent manner. P53 wild-type osteosarcoma cells were more sensitive to DHA. Moreover, the percentage of apoptotic cell and cell arrest in G₂/M phase was increased upon DHA treatment in a dose-dependent manner. Mechanistically, DHA activated caspase-3, caspase-8, and caspase-9; upregulated the expression of Bax, FAS, and cyclin D1; downregulated the expression of Bcl-2, Cdc25B, and cyclin B1; and inhibited the activity of NF-кB. In conclusion, DHA has significant anticancer effects against human osteosarcoma cells, which include induction of apoptosis and cell cycle arrest. The p53 gene may play a certain role in the DHA-induced human osteosarcoma apoptosis and cell cycle arrest. DHA is a novel anti-osteosarcoma drug candidate that merits further study.

Cryptotanshinone sensitizes DU145 prostate cancer cells to Fas(APO1/CD95)-mediated apoptosis through Bcl-2 and MAPK regulation

Fas/APO-1/CD95, a member of the tumor necrosis factor (TNF) receptor superfamily, is a potential anti-cancer factor as it can induce apoptosis in tumor cells. However, despite the fact that many cancer cells express Fas on the membrane, some tumors such as prostate cancer display resistance to Fas-induced apoptosis. In these cases, combination therapy using chemotherapeutic agents and Fas may be more suitable than therapy using Fas alone. In the present study, we demonstrate that the apoptosis inhibitory protein, Bcl-2, was highly expressed in response to Fas in DU145 prostate cancer cells, thereby conferring resistance to apoptosis. We have screened a number of naturally occurring products that may overcome this resistance. Here we report that cryptotanshinone, the major tanshinone isolated from Salvia miltiorrhiza Bunge, can suppress Bcl-2 expression and augment Fas sensitivity in DU145 cells. We further show that JNK and p38 MAPK act upstream of Bcl-2 expression in Fas-treated DU145 cells, and that cryptotanshinone significantly blocked activation of these kinases. Moreover, cryptotanshinone sensitized several tumor cells to a broad range of anti-cancer agents. Collectively, our data suggest that cryptotanshinone has therapeutic potential in the treatment of human prostate cancer.

Protective effect of Bojungbangdocktang on cisplatin-induced cytotoxicity and apoptosis in MCF-10A breast endothelial cells

Although cisplatin has been extensively used as a cancer chemotherapeutic agent for the treatment of various human cancers, it causes significant side effects such as nephrotoxicity and hepatotoxicity due to lethal bystander damage to normal cells. Thus, in the current study, we investigated the Oriental herbal medicine Bojungbangdocktang (BJBDT), as we reported previously its anti-angiogenic activity at nontoxic concentrations that could prevent cisplatin-induced toxicity and apoptosis in human normal breast epithelial cell MCF-10A, but not in MCF-7 and MDA MB-231 breast cancer cells. BJBDT protected cisplatin-induced cytotoxicity in MCF-10A cells and potentiated cytotoxicity and MMP loss in MCF-7 cells. Also, 4',6-diamidino-2-phenylindole (DAPI) staining and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assay revealed that BJBDT reduced cisplatin-induced apoptotic bodies in MCF-10A cells compared with cisplatin-treated control. Consistently, BJBDT attenuated the apoptotic portion sub-G1 DNA contents as well as blocked the activation of caspase-3 and -9 and poly(ADP-ribose)polymerase (PARP) cleavage in cisplatin-treated MCF-10A cells. Taken together, our findings suggest that BJBDT can protect cisplatin-induced cytotoxicity and apoptosis in normal MCF-10A breast cells as a cancer chemopreventive agent.

Convergent antifouling activities of structurally distinct bioactive compounds synthesized within two sympatric Haliclona demosponges

A wide range of sessile and sedentary marine invertebrates synthesize secondary metabolites that have potential as industrial antifoulants. These antifoulants tend to differ in structure, even between closely related species. Here, we determine if structurally divergent secondary metabolites produced within two sympatric haliclonid demosponges have similar effects on the larvae of a wide range of benthic competitors and potential fouling metazoans (ascidians, molluscs, bryozoans, polychaetes, and sponges). The sponges Haliclona sp. 628 and sp. 1031 synthesize the tetracyclic alkaloid, haliclonacyclamine A (HA), and the long chain alkyl amino alcohol, halaminol A (LA), respectively. Despite structural differences, HA and LA have identical effects on phylogenetically disparate ascidian larvae, inducing rapid larval settlement but preventing subsequent metamorphosis at precisely the same stage. HA and LA also have similar effects on sponge, polychaete, gastropod and bryozoan larvae, inhibiting both settlement and metamorphosis. Despite having identical roles in preventing fouling and colonisation, HA and LA differentially affect the physiology of cultured HeLa human cells, indicating they have different molecular targets. From these data, we infer that the secondary metabolites within marine sponges may emerge by varying evolutionary and biosynthetic trajectories that converge on specific ecological roles.

SMI of Bcl-2 TW-37 is active across a spectrum of B-cell tumors irrespective of their proliferative and differentiation status

The Bcl-2 family of proteins is critical to the life and death of malignant B-lymphocytes. Interfering with their activity using small-molecule inhibitors (SMI) is being explored as a new therapeutic strategy for treating B-cell tumors. We evaluated the efficacy of TW-37, a non-peptidic SMI of Bcl-2 against a range spectrum of human B-cell lines, fresh patient samples and animal xenograft models. Multiple cytochemical and molecular approaches such as acridine orange/ethidium bromide assay for apoptosis, co-immunoprecipitation of complexes and western blot analysis, caspase luminescent activity assay and apoptotic DNA fragmentation assay were used to demonstrate the effect of TW-37 on different B-cell lines, patient derived samples, as well as in animal xenograft models. Nanomolar concentrations of TW-37 were able to induce apoptosis in both fresh samples and established cell lines with IC50 in most cases of 165-320 nM. Apoptosis was independent of proliferative status or pathological classification of B-cell tumor. TW-37 was able to block Bim-Bcl-XL and Bim-Mcl-1 heterodimerization and induced apoptosis via activation of caspases -9, -3, PARP and DNA fragmentation. TW-37 administered to tumor-bearing SCID mice led to significant tumor growth inhibition (T/C), tumor growth delay (T-C) and Log10kill, when used at its maximum tolerated dose (40 mg/kg x 3 days) via tail vein. TW-37 failed to induce changes in the Bcl-2 proteins levels suggesting that assessment of baseline Bcl-2 family proteins can be used to predict response to the drug. These findings indicate activity of TW-37 across the spectrum of human B-cell tumors and support the concept of targeting the Bcl-2 system as a therapeutic strategy regardless of the stage of B-cell differentiation.

Antiapoptotic mechanisms of Chinese medicine formula, Guan-Xin-Er-Hao, in the rat ischemic heart

Considerable evidence indicates that apoptosis plays a critical role in acute myocardial infarction. We have previously shown that Guan-Xin-Er-Hao (GXEH), a Chinese medicine formula, attenuates postischemia myocardial apoptosis. The present study was designed to determine the mechanisms by which GXEH exerts its antiapoptotic effect. Adult male Sprague-Dawley rats were randomized to receive vehicle or GXEH (5 or 15 g/kg) orally 30 min before ischemia and subjected to myocardial ischemia of 3 h (apoptosis peak) or 24 h (necrosis peak) for determination of infarct size. Compared with rats receiving vehicle, those rats treated with GXEH (15 g/kg) showed significantly reduced infarct size, the reduced myocardial apoptosis, as judged by the decreases in TUNEL-positive staining (22.40 +/- 5.68% vs. 40.31 +/- 10.58%, p < 0.01), and the decrease in the degree of caspase-3 activation (82.97 +/- 10.54 vs. 159.95 +/- 9.16 mumol cleaved acetyl-Asp-Glu-Val-Asp-p-nitroanilide/mg protein, p < 0.01). Treatment with GXEH (15 g/kg) significantly reduced the release of mitochondrial cytochrome c, a primary mediator of apoptosis, the degree of caspase-9 activation, and the Bax/Bcl-2 ratio. Caspase-9 cleaves and activates caspase-3. Bax promotes apoptosis, while Bcl-2 inhibits apoptosis. Thus, the antiapoptotic mechanisms of GXEH may involve the mitochondrial cytochrome c-mediated caspase-3 activation in cardiomyocytes after acute myocardial infarction. Taken together, GXEH tilted the balance between Bax and Bcl-2 toward an antiapoptotic state, decreased mitochondrial cytochrome c release, reduced caspase-9 activation, and attenuated subsequent caspase-3 activation and postischemic myocardial apoptosis in rats. GXEH may be used as a promising agent for future treatment of cardiovascular diseases.

Interleukin 18 in the heart

IL-18, originally termed as interferon gamma (IFN-gamma) inducing factor, is a proinflammatory cytokine that belongs to the IL-1 cytokine superfamily. IL-18 plays an important role in immune, infectious, and inflammatory diseases due to its induction of IFN-gamma. However, accumulated evidence has demonstrated that other effects of IL-18 are independent of IFN-gamma. Here, we reviewed the current literatures regarding the role of IL-18 in the heart and cardiovascular system. Infiltrated neutrophils, resident macrophages, endothelial cells, smooth muscle cells, and cardiomyocytes in the heart are able to produce IL-18 in response to injury. IL-18 is produced as a biologically inactive precursor (pro-IL-18) that is activated by caspase 1 (the IL-1beta converting enzyme). Elevated IL-18 levels have been observed in cardiac tissue and circulation after myocardial I/R and sepsis. The possible cellular and molecular mechanisms concerning IL-18-induced myocardial injury include induction of inflammation, increased apoptosis, a cardiac hypertrophy effect, modulation of mitogen activated protein kinase activation, and changes in intracellular calcium. Finally, we briefly reviewed the therapeutic strategies for inhibiting IL-18's biological activity to protect cardiac tissue from injury.

Costunolide-induced apoptosis is caused by receptor-mediated pathway and inhibition of telomerase activity in NALM-6 cells

Costunolide, isolated from the stem bark of Magnolia sieboldii, is a sesquiterpene lactone that exhibits various biological and immunological actions. We investigated the induction mechanism of apoptosis by costunolide in a human B cell leukemia NALM-6 cell culture system. Costunolide (10 microM)-induced apoptosis time-dependently increased, estimated by nuclear damage observation and flow cytometric analysis. Costunolide did not change Fas-associated factor 1 (FAF1), but the phosphorylation of Fas-associated death domain (FADD) at serine 194 increased from early treatment. The activation of caspase-8 and -9 and degradation of poly-(ADP-ribose) polymerase (PARP) was time-dependently detected by incubation with costunolide. Pretreatment of cells with caspase-3, -8 and broad spectrum caspase inhibitors significantly blocked costunolide-induced apoptosis, but caspase-9 inhibitor failed to block apoptosis. Telomerase activity was significantly suppressed after treatment with costunolide, and human telomerase reverse transcriptase (hTERT), a critical determinant of the enzyme activity of telomerase, decreased the expression of both mRNA and protein levels by costunolide. Costunolide-induced repression of telomerase was prevented by pretreatment of cells with caspase-3, -8 and broad spectrum caspase inhibitors, but caspase-9 inhibitor was no effect. These data suggest that one of the costunolide-induced apoptotic mechanisms is that the receptor-mediated pathway precedes the mitochondria-dependent pathway, caused by the inhibition of telomerase activity via suppression of hTERT in NALM-6 cells.

The herb medicine formula "Yang Wei Kang Liu" improves the survival of late stage gastric cancer patients and induces the apoptosis of human gastric cancer cell line through Fas/Fas ligand and Bax/Bcl-2 pathways

The herb medicine formula "Yang Wei Kang Liu" (YWKLF) has been used to inhibit the metastasis of human gastric cancer to prolong patient survival. In this study, we evaluated the effect of combination of chemotherapy with YWKLF on the survival of stage IV gastric cancer patients and the potential mechanisms of YWKLF by focusing on its capacity to activate apoptotic pathways in human gastric cancer cell line MGC-803. We found that combination of chemotherapy with oral administration of YWKLF significantly increased the survival of stage IV gastric cancer patients. In an approach of "serum pharmacology" in which sera were collected from rabbits orally administered with YWKLF and examined for their anti-tumor cell activity in vitro, we observed that sera from rabbits administered with YWKLF induced the apoptosis of MGC-803 cells by causing the loss of mitochondrial membrane potential, increasing the expression of Fas protein and Bax mRNA, as well as down-regulating Fas-L mRNA. Our results suggest that activation of major pro-apoptotic pathways may account for the anti-gastric cancer activity of YWKLF, which may provide a basis for isolation and identification of more highly effective anti-cancer components.

Extracellular signal-regulated kinase activation by Neisseria gonorrhoeae downregulates epithelial cell proapoptotic proteins Bad and Bim

Neisseria gonorrhoeae expressing type IV pili (Tfp) activates extracellular signal-regulated kinase (ERK) and induces a cytoprotective state in the epithelial cell in a manner that is enhanced by pilT. As the ERK signaling pathway is well-known for its role in cytoprotection and cell survival, we tested the hypothesis that ERK is involved in producing this cytoprotective effect. Inhibiting ERK activation prior to infection attenuated the ability of these bacteria to induce cytoprotection. Activated ERK specifically targeted two proapoptotic Bcl-2 homology domain 3 (BH3)-only proteins, Bim and Bad, for downregulation at the protein level. Bim downregulation occurred through the proteasome. ERK, in addition, inactivated Bad by triggering its phosphorylation at Ser112. Finally, reducing the level of either Bad or Bim alone by small interfering RNA was sufficient to protect uninfected cells from staurosporine-induced apoptosis. We conclude that Tfp-induced cytoprotection is due in part to ERK-dependent modification and/or downregulation of proapoptotic proteins Bad and Bim.