Cell death by apoptosis and its protective role against disease

Synthetic phenolic antioxidants: Metabolism, hazards and mechanism of action

Synthetic phenolic antioxidants can interact with peroxides produced by food. This paper reviews correlation between BHA, BHT and TBHQ metabolism and harms they cause and provides a theoretical basis for rational use of BHA, BHT and TBHQ in food, and also put some attention on the transformation and metabolic products of PG. We introduce BHA, BHT, TBHQ, PG and their possible metabolic pathways, and discuss possible harms and their specific mechanisms responsible. Excessive addition or incorrect use of synthetic phenolic antioxidants results in carcinogenicity, cytotoxicity, oxidative stress induction and endocrine disrupting effects, which warrant attention. BHA carcinogenicity is related to production of metabolites TBHQ and TQ, and cytotoxic effect of BHA is the main cause of apoptosis induction. BHT carcinogenicity depends on DNA damage degree, and tumour promotion is mainly related to production of quinone methylation metabolites. TBHQ carcinogenicity is related to induction of metabolite TQ and enzyme CYP1A1.

Cytotoxic components from the leaves of Erythrophleum fordii induce human acute leukemia cell apoptosis through caspase 3 activation and PARP cleavage

Cassaine diterpenoids as erythrofordins A-C (1-3), pseudo-erythrosuamin (4), and erythrofordin U (5) isolated from the leaves of Vietnamese Erythrophleum fordii Oliver were tested cytotoxic activity against human leukemia cancer cells. The results showed that these metabolites exhibited dose-dependent cytotoxicity against human leukemia HL-60 and KG cells with IC₅₀ values ranging from 15.2 ± 1.5 to 42.2 ± 3.6 µM. Treatment with erythrofordin B led to the apoptosis of HL-60 and KG cells due to the activation of caspase 3, caspase 9, and poly (ADP-ribose) polymerase (PARP). Erythrofordin B significantly increased Bak protein expression, but downregulated the anti-apoptotic protein Bcl-2, in HL-60 cells. In silico results demonstrated that erythrofordin B can bind to both the procaspase-3 allosteric site and the PARP-1 active site, with binding energies of -7.36 and -10.76 kcal/mol, respectively. These results indicated that the leaves of Vietnamese E. fordii, which contain cassaine diterpenoids, can induce the apoptosis of human leukemia cancer cells.

Curcumin, a Multifaceted Hormetic Agent, Mediates an Intricate Crosstalk between Mitochondrial Turnover, Autophagy, and Apoptosis

Curcumin has extensive therapeutic potential because of its antioxidant, anti-inflammatory, and antiproliferative properties. Multiple preclinical studies in vitro and in vivo have proven curcumin to be effective against various cancers. These potent effects are driven by curcumin's ability to induce G2/M cell cycle arrest, induce autophagy, activate apoptosis, disrupt molecular signaling, inhibit invasion and metastasis, and increase the efficacy of current chemotherapeutics. Here, we focus on the hormetic behavior of curcumin. Frequently, low doses of natural chemical products activate an adaptive stress response, whereas high doses activate acute responses like autophagy and cell death. This phenomenon is often referred to as hormesis. Curcumin causes cell death and primarily initiates an autophagic step (mitophagy). At higher doses, cells undergo mitochondrial destabilization due to calcium release from the endoplasmic reticulum, and die. Herein, we address the complex crosstalk that involves mitochondrial biogenesis, mitochondrial destabilization accompanied by mitophagy, and cell death.

Molecular hybridization of grape seed extract: Synthesis, structural characterization and anti-proliferative activity in vitro

The grape seed extract (GSE) hybridized with medium-chain saturated fatty acids (decanoic acid) exhibited higher lipophilicity, antioxidant activity, and anti-proliferative activity than its parents. The chemical structures of individual hybridized GSE derivatives were identified as 3'-O-decanoyl catechin, 3'-O-decanoyl epicatechin, 3', 5'-2-O-decanoyl epigallocatechin, and 3', 4', 3″, 5″-4-O-decanoyl epicatechin gallate by HPLC-MS² and ¹H and ¹³C NMR. For growth inhibitory effect on HepG2 cells, hybridized GSE derivatives (EC₅₀ = 44.38 μg/mL) were significantly (p < 0.01) stronger than natural GSE (EC₅₀ = 60.83 μg/mL) due to increased lipophilicity. The effects of GSE derivatives on apoptosis and cell cycle in HepG2 cells were further evaluated by flow cytometry. The results showed that the percentage of apoptotic cells increased markedly in the presence of hybridized GSE derivatives. Moreover, hybridized GSE derivatives were capable of inducing cell cycle arrest in G1 phase. This research suggests that hybridized GSE derivatives are effective lipophilic antioxidants and show the potential as adjuvant therapy for cancer.

Gap Junction Intercellular Communication in the Carcinogenesis Hallmarks: Is This a Phenomenon or Epiphenomenon?

If occupational tumors are excluded, cancer causes are largely unknown. Therefore, it appeared useful to work out a theory explaining the complexity of this disease. More than fifty years ago the first demonstration that cells communicate with each other by exchanging ions or small molecules through the participation of connexins (Cxs) forming Gap Junctions (GJs) occurred. Then the involvement of GJ Intercellular Communication (GJIC) in numerous physiological cellular functions, especially in proliferation control, was proven and accounts for the growing attention elicited in the field of carcinogenesis. The aim of the present paper is to verify and discuss the role of Cxs, GJs, and GJIC in cancer hallmarks, pointing on the different involved mechanisms in the context of the multi-step theory of carcinogenesis. Functional GJIC acts both as a tumor suppressor and as a tumor enhancer in the metastatic stage. On the contrary, lost or non-functional GJs allow the uncontrolled proliferation of stem/progenitor initiated cells. Thus, GJIC plays a key role in many biological phenomena or epiphenomena related to cancer. Depending on this complexity, GJIC can be considered a tumor suppressor in controlling cell proliferation or a cancer ally, with possible preventive or therapeutic implications in both cases.

Effect of endoplasmic reticulum calcium on paraquat‑induced apoptosis of human lung type II alveolar epithelial A549 cells

The present study aimed to explore the role of endoplasmic reticulum calcium (ER Ca2+) in the apoptosis of human lung type II alveolar epithelial A549 cells induced by paraquat (PQ) in vitro. PQ significantly elevated the intracellular Ca2+ concentration. Treatment with the Ca2+‑ATPase inhibitor thapsigargin significantly increased PQ‑induced cytotoxicity, elevated the intracellular level of Ca2+, and increased the apoptosis rate, the protein expression of glucose‑regulated protein 78 (GRP78) and C/EBP homologous protein (CHOP), and the activities of caspase‑7 and caspase‑12 in PQ‑treated cells. By contrast, treatment with heparin, an inositol 1,4,5‑triphosphate receptor inhibitor, remarkably attenuated cytotoxicity and decreased the intracellular level of Ca2+, the apoptosis rate and the expression levels of GRP78, CHOP and Caspases. In conclusion, PQ impaired the regulating function of ER Ca2+ and resulted in an excessive increase of intracellular Ca2+. Therefore, influencing the Ca2+ signaling in the ER influenced the apoptosis of A549 cells via the ER stress pathway.

Expression of P53, BAX, and BCL-2 in human malignant melanoma and squamous cell carcinoma cells after tea tree oil treatment in vitro

Tea tree oil (TTO) is an essential oil obtained by steam distillation from the leaves of Melaleuca alternifolia (Myrtaceae). This oil has traditionally been used for the treatment of various skin infections. The present study aimed to investigate the cytotoxic effects of TTO against two representative types of human skin cancer, namely malignant melanoma (A-375) and squamous cell carcinoma (HEp-2).To outline the basic molecular mechanism involved in apoptosis induction in A-375 and HEp-2 cell lines, Annexin V/PI staining for apoptosis detection, cell cycle analysis were monitored using flow cytometry and mRNA expression levels of the apoptosis-regulatory genes P53, BAX, and BCL-2 were determined by real-time PCR and western blot after treatment with TTO. Results showed that TTO exhibited a strong cytotoxicity towards A-375 and HEp-2 cell lines, with IC50 values of 0.038% (v/v) and 0.024% (v/v) respectively. This cytotoxicity resulted from TTO induced apoptosis in both A-375 and HEp-2 cell lines as evidenced by morphological features of apoptosis and Annexin V/PI staining results in addition to the activation of caspase-3/7 and -9, upregulation of pro-apoptotic genes (P53 and BAX) and downregulation of the anti-apoptotic gene BCL-2. Additionally, cell cycle analysis showed that TTO caused cell cycle arrest mainly at G2/M phase. Taken together, the results of this study reveal that TTO is an effective apoptosis inducer in A-375 and HEp-2 cancer cell lines, indicating that it could be a promising chemopreventive candidate to be used in topical formulations against melanoma and squamous cell cancers; however, further in vivo studies may be warranted.

The principle of safety evaluation in medicinal drug - how can toxicology contribute to drug discovery and development as a multidisciplinary science?

Pharmaceutical (drug) safety assessment covers a diverse science-field in the drug discovery and development including the post-approval and post-marketing phases in order to evaluate safety and risk management. The principle in toxicological science is to be placed on both of pure and applied sciences that are derived from past/present scientific knowledge and coming new science and technology. In general, adverse drug reactions are presented as "biological responses to foreign substances." This is the basic concept of thinking about the manifestation of adverse drug reactions. Whether or not toxic expressions are extensions of the pharmacological effect, adverse drug reactions as seen from molecular targets are captured in the category of "on-target" or "off-target", and are normally expressed as a biological defense reaction. Accordingly, reactions induced by pharmaceuticals can be broadly said to be defensive reactions. Recent molecular biological conception is in line with the new, remarkable scientific and technological developments in the medical and pharmaceutical areas, and the viewpoints in the field of toxicology have shown that they are approaching toward the same direction as well. This paper refers to the basic concept of pharmaceutical toxicology, the differences for safety assessment in each stage of drug discovery and development, regulatory submission, and the concept of scientific considerations for risk assessment and management from the viewpoint of "how can multidisciplinary toxicology contribute to innovative drug discovery and development?" And also realistic translational research from preclinical to clinical application is required to have a significant risk management in post market by utilizing whole scientific data derived from basic and applied scientific research works. In addition, the significance for employing the systems toxicology based on AOP (Adverse Outcome Pathway) analysis is introduced, and coming challenges on precision medicine are to be addressed for the new aspect of efficacy and safety evaluation.

Soluble Asialoglycoprotein Receptors Reflect the Apoptosis of Hepatocytes

Cell death is thought to take place through at least two distinct processes: apoptosis and necrosis. There is increasing evidence that dysregulation of the apoptotic program is involved in liver diseases. However, there is no method to simply evaluate apoptosis in the liver tissue at present. It has been reported that the expression of asialoglycoprotein receptors (AGPRs) increases with apoptosis, but there is no report until now that investigates the influence of soluble AGPRs on apoptosis of hepatocytes. Soluble AGPRs have been reported to be present in human serum under physiological conditions. In the present study, in order to investigate the correlation between apoptosis of hepatocytes and soluble AGPR, mouse soluble AGPRs were detected using SDS-PAGE and Western blot analysis was conducted using anti-extracellular mouse hepatic lectin-1 (Ex-MHL-1) antiserum (polyclonal rabbit serum). The mouse soluble AGPRs were present in culture medium and mouse serum when hepatocytes were damaged. The soluble AGPRs increased proportionately, as the number of dead hepatocytes increased. In addition, soluble AGPRs existed more when apoptotic cell death was observed in in vitro and in vivo than when necrotic cell death was observed. The extracellular moiety of MHL-1 exists in the culture medium and mouse serum as a soluble AGPR, but the detailed mechanism of releasing soluble AGPR from hepatocytes has not been revealed yet. We described the first evidence for the relation between quantity of soluble AGPRs with two kinds of cell death: necrosis and apoptosis. Based on the results of our study, soluble AGPRs might become a new marker of apoptosis in the liver tissue and be useful for clinical diagnosis and treatment for liver diseases.

Hepatoprotective Mongolian prescription II enhances the antitumor effects of chemotherapeutics in hepatocellular carcinoma xenografts

Hepatoprotective Mongolian prescription II (MPII), a mixture of 18 different medicinal herbs, significantly inhibited the growth of human liver cancer cell lines Huh-7 and HepG2 in vitro with different concentrations; MPII (6mg/mL) inhibited cell proliferation by 80.48%. MPII induced apoptosis in both cell lines, which was observed by light microscopy and flow cytometry. MPII-induced apoptosis and G0/G1 cell cycle arrest were quantified by Annexin V-FITC/PI staining and flow cytometry. At the molecular level, MPII induced caspase-3, caspase-8, caspase-9, and cytochrome c gene expression. In vivo, MPII dramatically inhibited human liver tumor growth in a xenograft model in Kunming mice with no apparent cytotoxicity to the hosts. Apoptotic genes (Bcl-2 and Bax) are up-regulated, suggesting that the ratio of Bcl-2/Bax was statistically significant, indicating that the drugs had affected the expression of apoptosis genes, especially on induce apoptosis gene Bax. We also observed an attenuated effect when MPII was used in combination with chemotherapy drug 5-fluorouracil (5-FU). The mice treated with 5-FU alone did not show a concentration-dependent effect, but 5-FU in combination with MPII displayed concentration-dependent effects on liver cancer cells. Our study suggests that MPII works by inducing apoptosis and cell cycle arrest, and has the potential to be a powerful anticancer agent.

Cytokines in recurrent miscarriage

Cytokines act at all stages of pregnancy from implantation to parturition. This review examines their relevance in recurrent miscarriage. However, recurrent miscarriage may be due to an inherently abnormal embryo (e.g., chromosomal abberations) or maternal factors (e.g., uterine anomalies or antiphospholipid antibodies). In the former, cytokines are not causitive, but may be part of the mechanism of abortion. In the antiphospholipid syndrome, cytokines such as TNFa and IL-6 may be responsible for the associated thrombosis. Hence, an appropriate cytokine milieu could be responsible for whether the antibodies are pathogenic or merely an epiphenomenon. Natural killer cells seem to have a key role in immunosurveillance of the invading trophoblast. However, if activated by TNFa, natural killer cells may induce apoptosis in the trophoblast possibly leading to miscarriage. This action is inhibited by TGFb. Early ultrasound scanning and embryoscopy have revealed structural anomalies in karyotypically normal embryos which have terminated in first trimester missed abortion. Teratogens such as cyclophosphamide cause fetal demise by excessive apoptosis. Excessive apoptosis may be mediated by TNFa, TGFb and other cytokines. GM-CSF has been reported to prevent teratogenesis in laboratory animals. Both immunomodulation and hormonal support (progesterone or hCG supplements) have been used to improve the live birth rate in recurrently aborting women. Each may modulate the balance between various cytokines. Although neither hormonal support or immunopotentiation have been proven to be beneficial, the results and the role of cytokines themselves can only be assessed in trials of karyotypically normal embryos.

Dose-Dependent Modulation of Cell Death: Apoptosis Versus Necrosis in Thioacetamide Hepatotoxicity

Apoptosis is programmed cell death, morphologically and biochemically distinct from necrosis. The objective of the present study was to examine thioacetamide-induced apoptosis over an early time course of 0 to 8 h after administration of a 12-fold dose range (50, 150, 300, and 600 mg/kg, ip) of thioacetamide (TA). Male Sprague-Daw ley rats (200-225 g) were used for the study. The incidence of apoptosis was determined by in situ end labeling, transmission electron microscopy, and charge modification of heat shock protein 70 (Hsp 70). Light microscopic examination of liver sections revealed apoptotic bodies (ABs)as early as 2 h after TA administration. A dose-dependent increase in the incidence of ABs was seen with all doses until 4 h. Thereafter, the incidence of ABs continued to increase in a temporal manner with 50 and 150 mg/kg, while it decreased in the rats treated with 300 and 600 mg/kg. Between 4 and 8 h, while necrosis as assessed by serum alanine aminotransferase (ALT) and histopathology declined in the sixfold dose range (50, 150, and 300 mg TA/kg), it increased in a temporal manner with 600 mg TA/kg. Preliminary studies indicate an inverse relation between Hsp 70 abundance and the incidence of apoptosis. Hsp 70 expression was significantly higher in the 600 mg TA/kg group compared to the lower doses. Lowest abundance was recorded in the groups receiving 50 and 150 mg TA/kg, where maximum apoptosis was noted. These findings collectively suggest that although the processes of apoptosis and necrosis are initiated simultaneously, the proportion of cells dying via either mechanism seems to be regulated by the dose of TA. Lower doses seem to favor cell death via apoptosis, while higher doses favor cell death via necrosis. Additionally, the inverse relation between Hsp 70 and apoptosis at lower doses suggests a regulatory role for Hsp 70.

Using Small Molecules to Dissect Non-apoptotic Programmed Cell Death: Necroptosis, Ferroptosis, and Pyroptosis

Genetically programmed cell death is a universal and fundamental cellular process in multicellular organisms. Apoptosis and necroptosis, two common forms of programmed cell death, play vital roles in maintenance of homeostasis in metazoans. Dysfunction of the regulatory machinery of these processes can lead to carcinogenesis or autoimmune diseases. Inappropriate death of essential cells can lead to organ dysfunction or even death; ischemia-reperfusion injury and neurodegenerative disorders are examples of this. Recently, novel forms of non-apoptotic programmed cell death have been identified. Although these forms of cell death play significant roles in both physiological and pathological conditions, the detailed molecular mechanisms underlying them are still poorly understood. Here, we discuss progress in using small molecules to dissect three forms of non-apoptotic programmed cell death: necroptosis, ferroptosis, and pyroptosis.

Effects of the administration of epidermal growth factor receptor specific inhibitor cetuximab, alone and in combination with cisplatin, on proliferation and apoptosis of Hep-2 laryngeal cancer cells

BACKGROUND

Epidermal growth factor receptor (EGFR) overexpression and prognostic value in head and neck squamous cell cancer is the basis for targeting by anti-EGFR antibodies, which increase the efficacy of radiotherapy. In order to evaluate the best therapeutic schedule, the effects of cetuximab (C225) on Hep-2 cell proliferation, alone and in combination with cisplatin, were studied.

METHODS

Hep-2 cells were treated with cetuximab alone or in combination with cisplatin. After determining cell viability with trypan blue, morphological features of apoptotic degeneration were analysed by fluorescence microscopy with Hoechst 33258 stain.

RESULTS

Cetuximab alone mildly inhibited Hep-2 proliferation and showed no pro-apoptotic effects. When administered concomitantly with cisplatin, cetuximab synergistically increased inhibition of proliferation and apoptosis.

CONCLUSION

The antiproliferative activity of cetuximab is consistent with its hypothesised role in inhibiting repopulation. However, the increase in the effects of pro-apoptotic agents induced by cetuximab may be even more relevant to its clinical effectiveness than the inhibition of repopulation.

Silymarin inhibits melanoma cell growth both in vitro and in vivo by targeting cell cycle regulators, angiogenic biomarkers and induction of apoptosis

Cutaneous malignant melanoma is the leading cause of death from skin diseases and is often associated with activating mutations of the proto-oncogene BRAF. To develop more effective strategies for the prevention or treatment of melanoma, we have examined the inhibitory effects of silymarin, a flavanoid from Silybum marianum, on melanoma cells. Using A375 (BRAF-mutated) and Hs294t (non BRAF-mutated but highly metastatic) human melanoma cell lines, we found that in vitro treatment with silymarin resulted in a dose-dependent: (i) reduction in cell viability; (ii) enhancement of either Go/G1 (A375) or G2-M (Hs294t) phase cell cycle arrest with corresponding alterations in cyclins and cyclin-dependent kinases; and (iii) induction of apoptosis. The silymarin-induced apoptosis of human melanoma cells was associated with a reduction in the levels of anti-apoptotic proteins (Bcl-2 and Bcl-xl), an increase in the levels of pro-apoptotic protein (Bax), and activation of caspases. Further, oral administration of silymarin (500 mg/kg body weight/2× a week) significantly inhibited (60%, P < 0.01) the growth of BRAF-mutated A375 melanoma tumor xenografts, and this was associated with: (i) inhibition of cell proliferation; (ii) induction of apoptosis of tumor cells; (iii) alterations in cell cycle regulatory proteins; and (iv) reduced expression of tumor angiogenic biomarkers in tumor xenograft tissues. These results indicate that silymarin may have a chemotherapeutic effect on human melanoma cell growth and warrant its further evaluation.

Cytotoxic and apoptotic effects of boron compounds on leukemia cell line

In this study we investigated the effects of boric acid and sodium tetraborate on an acute leukemia cell line and healthy human lymphocytes. We evaluated the effects of boric acid and sodium tetraborate on the HL-60 cell line and healthy human lymphocytes by using the methods of MTT, Neutral Red, AO (flow cytometry) and transmission electron microscope. We found that there were dead cells at a concentration of 500 µM boric acid and sodium tetraborate (50 % and 40 %, respectively). An apoptotic effect was found at a concentration of 1,000 µM concentration in normal lymphocytes and HL-60 (acute leukemia cells) cells (2.5 % and 8.8 % respectively). We observed that boric acid at a concentration of 500 µM caused double nucleus and micronucleus formation in both HL-60 cells and lymphocytes. An expansion in mitochondrial dimension and deformation in cristas also appeared. Our findings suggest that boric acid is more effective than sodium tetraborate on the HL-60, and boric acid in particular showed a cytotoxic effect on HL-60 in comparison to healthy lymphocytes and it also affected the mitochondrial pathway.

Methanol extract from Vietnamese Caesalpinia sappan induces apoptosis in HeLa cells

Background

This study evaluated the cytotoxic activity of extracts from Caesalpinia sappan heartwood against multiple cancer cell lines using an MTT cell viability assay. The cell death though induction of apoptosis was as indicated by DNA fragmentation and caspase-3 enzyme activation.

Results

A methanol extract from C. sappan (MECS) showed cytotoxic activity against several of the cancer cell lines. The most potent activity exhibited by the MECS was against HeLa cells with an IC₅₀ value of 26.5 ± 3.2 μg/mL. Treatment of HeLa cells with various MECS concentrations resulted in growth inhibition and induction of apoptosis, as indicated by DNA fragmentation and caspase-3 enzyme activation.

Conclusion

This study is the first report of the anticancer properties of the heartwood of C. sappan native to Vietnam. Our findings demonstrate that C. sappan heartwood may have beneficial applications in the field of anticancer drug discovery.

ARP2, a novel pro-apoptotic protein expressed in epithelial prostate cancer LNCaP cells and epithelial ovary CHO transformed cells

Neoplastic epithelial cells generate the most aggressive types of cancers such as those located in the lung, breast, colon, prostate and ovary. During advanced stages of prostate cancer, epithelial cells are associated to the appearance of androgen-independent tumors, an apoptotic-resistant phenotype that ultimately overgrows and promotes metastatic events. We have previously identified and electrophysiologically characterized a novel Ca(2+)-permeable channel activated during apoptosis in the androgen-independent prostate epithelial cancer cell line, LNCaP. In addition, we reported for the first time the cloning and characterization of this channel-like molecule named apoptosis regulated protein 2 (ARP2) associated to a lethal influx of Ca(2+) in Xenopus oocytes. In the present study, LNCaP cells and Chinese hamster ovary cells (CHO cell line) transfected with arp2-cDNA are induced to undergo apoptosis showing an important impact on cell viability and activation of caspases 3 and 7 when compared to serum deprived grown cells and ionomycin treated cells. The subcellular localization of ARP2 in CHO cells undergoing apoptosis was studied using confocal microscopy. While apoptosis progresses, ARP2 initially localized in the peri-nuclear region of cells migrates with time towards the plasma membrane region. Based on the present results and those of our previous studies, the fact that ARP2 constitutes a novel cation channel is supported. Therefore, ARP2 becomes a valuable target to modulate the influx and concentration of calcium in the cytoplasm of epithelial cancer cells showing an apoptotic-resistant phenotype during the onset of an apoptotic event.

Dose-dependent regulation of superoxide anion on the proliferation, differentiation, apoptosis and necrosis of human hepatoma cells: the role of intracellular Ca2+

Dose-dependent regulation of cellular processes is one important characteristic of signaling molecules. Although recent studies suggest that reactive oxygen species (ROS) may act as in vivo signaling molecules, the dose-dependent regulation of ROS on cellular processes together in one system needs to be evaluated. After treating cells with gradually increased O(2)(-), generated by the hypoxanthine-xanthine oxidase system, it was found that: (i) the proliferation of hepatoma cells firstly increased at 1-2 microM O(2)(-), then decreased markedly as the concentration increased; (2) at 8 or 16 microM O(2)(-), re-differentiation of hepatoma cells was induced, as indicated by the indices relating to cell malignancy or differentiation, such as cell surface charge, alpha-fetoprotein, gamma-glutamyltranspeptidase, tyrosine-alpha-ketoglutarate transaminase, cAMP, and the tumor's clonogenic potential; (iii) at 16 microM O(2)(-), accompanied by the re-differentiation of cells, cell apoptosis was also simultaneously induced as indicated by the appearance of apoptotic bodies, detached cells, and other apoptotic morphological features, as well as specific DNA fragmentation; (iv) at the highest concentration of O(2)(-) (32 microM) in this study, cell necrosis was dramatically induced as shown by Trypan blue exclusion; (v), an increase of intracellular Ca(2+) ([Ca(2+)](i)) was observed at all concentrations of O(2)(-) treatment, and this [Ca(2+)](i) increase was found to be involved in the regulation of O(2)(-) on the cellular processes. In conclusion, these results indicate that O(2)(-) could dose-dependently regulate the processes of cells, where Ca(2+) is one of its molecular targets, and hence provide a direct support for the hypothesis that ROS themselves are important signaling molecules.

2,2'-diphenyl-3,3'-diindolylmethane: a potent compound induces apoptosis in breast cancer cells by inhibiting EGFR pathway

Despite recent advances in medicine, 30-40% of patients with breast cancer show recurrence underscoring the need for improved effective therapy. In this study, by in vitro screening we have selected a novel synthetic indole derivative 2,2'-diphenyl-3,3'-diindolylmethane (DPDIM) as a potential anti- breast cancer agent. DPDIM induces apoptosis both in vitro in breast cancer cells MCF7, MDA-MB 231 and MDA-MB 468 and in vivo in 7,12-dimethylbenz[α]anthracene (DMBA) induced Sprague-Dawley (SD) rat mammary tumor. Our in vitro studies show that DPDIM exerts apoptotic effect by negatively regulating the activity of EGFR and its downstream molecules like STAT3, AKT and ERK1/2 which are involved in the proliferation and survival of these cancer cells. In silico predictions also suggest that DPDIM may bind to EGFR at its ATP binding site. DPDIM furthermore inhibits EGF induced increased cell viability. We have also shown decreased expression of pro-survival factor Bcl-XL as well as increase in the level of pro-apoptotic proteins like Bax, Bad, Bim in DPDIM treated cells in vitro and in vivo. Our results further indicate that the DPDIM induced apoptosis is mediated through mitochondrial apoptotic pathway involving the caspase-cascade. To the best of our knowledge this is the first report of DPDIM for its anticancer activity. Altogether this report suggests that DPDIM could be an effective therapeutic agent for breast cancer.

Steroids from Commiphora mukul display antiproliferative effect against human prostate cancer PC3 cells via induction of apoptosis

Two new stigmastane-type steroids, stigmasta-5,22E-diene-3β,11α-diol (1) and stigmasta-5,22E-diene-3β,7α,11α-triol (2), together with eight known compounds, were isolated from the resinous exudates of Commiphora mukul. Their structures were established by extensive analysis of their HR-MS, 1D- and 2D-NMR (COSY, HMQC, HMBC and NOESY) spectra. The isolates were evaluated for their antiproliferative activities against four human cancer cell lines. Compound 2 demonstrated inhibitory effects with IC(50) values of 5.21, 9.04, 10.94 and 16.56 μM, respectively, against K562, MCF-7, PC3 and DU145 human cancer cell lines. Further study showed that 2 was able to enforce the PC3 cell cycle arrest in the G2/M phase, and induce the apoptosis of PC3 cells by activation of Bax, caspases 3 and 9, and by inhibition of Bcl-2. It was also found that 1 inhibited proliferation of PC3 cells via G0/G1 phase arrest of the cell cycle.

Increased expression of GAPDH protein is not indicative of nitrosative stress or apoptosis in liver of starved rainbow trout (Oncorhynchus mykiss)

Short-term starvation has been linked to in vivo protein degradation in liver of rainbow trout (Oncorhynchus mykiss). However, it is unclear whether this proposed increase in protein degradation is followed by programmed cell death (apoptosis) in liver of starved trout. A preliminary study in our laboratory revealed an isoform of glyceraldehyde-3-phosphate dehydrogenase (GAPDH) protein that increased 4.5-fold in liver of starved trout. GAPDH is a glycolytic enzyme involved in other cellular functions, including apoptosis. Increased intracellular nitric oxide (NO) promotes nuclear translocation of GAPDH that is associated with increased apoptosis in mammals. If GAPDH protein is associated with apoptosis in rainbow trout, it could potentially be used as a biomarker of cellular stress in liver of teleost fish species. The purpose of this study was to determine whether increased GAPDH protein expression in liver of starved rainbow trout is associated with NO-induced apoptosis. Targeted proteomic analysis using multiple reaction monitoring (MRM) was used to determine the level of GAPDH in nuclear and cytoplasmic fractions and inducible nitric oxide synthase (iNOS) in cell lysates. Dot blot and DNA fragmentation analyses were conducted to evaluate protein S-nitrosylation and apoptosis, respectively. Results showed that cytoplasmic GAPDH was 3.4-fold higher in liver of starved versus fed rainbow trout but could not be detected in nuclear fractions. Starvation significantly reduced hepato-somatic index but had no effect on iNOS protein expression, protein S-nitrosylation, or apoptosis. Our results indicate that starvation promoted significant reduction in liver mass that was not associated with increased apoptosis or NO-induced stress and that greater GAPDH concentration in liver of starved rainbow trout was located primarily in the cytoplasm.

Grape proanthocyanidins induce apoptosis by loss of mitochondrial membrane potential of human non-small cell lung cancer cells in vitro and in vivo

Lung cancer remains the leading cause of cancer-related deaths worldwide, and non-small cell lung cancer (NSCLC) represents approximately 80% of total lung cancer cases. The use of non-toxic dietary phytochemicals can be considered as a chemotherapeutic strategy for the management of the NSCLC. Here, we report that grape seed proanthocyanidins (GSPs) induce apoptosis of NSCLC cells, A549 and H1299, in vitro which is mediated through increased expression of pro-apoptotic protein Bax, decreased expression of anti-apoptotic proteins Bcl2 and Bcl-xl, disruption of mitochondrial membrane potential, and activation of caspases 9, 3 and poly (ADP-ribose) polymerase (PARP). Pre-treatment of A549 and H1299 cells with the caspase-3 inhibitor (z-DEVD-fmk) significantly blocked the GSPs-induced apoptosis of these cells confirmed that GSPs-induced apoptosis is mediated through activation of caspases-3. Treatments of A549 and H1299 cells with GSPs resulted in an increase in G1 arrest. G0/G1 phase of the cell cycle is known to be controlled by cyclin dependent kinases (Cdk), cyclin-dependent kinase inhibitors (Cdki) and cyclins. Our western blot analyses showed that GSPs-induced G1 cell cycle arrest was mediated through the increased expression of Cdki proteins (Cip1/p21 and Kip1/p27), and a simultaneous decrease in the levels of Cdk2, Cdk4, Cdk6 and cyclins. Further, administration of 50, 100 or 200 mg GSPs/kg body weight of mice by oral gavage (5 d/week) markedly inhibited the growth of s.c. A549 and H1299 lung tumor xenografts in athymic nude mice, which was associated with the induction of apoptotic cell death, increased expression of Bax, reduced expression of anti-apoptotic proteins and activation of caspase-3 in tumor xenograft cells. Based on the data obtained in animal study, human equivalent dose of GSPs was calculated, which seems affordable and attainable. Together, these results suggest that GSPs may represent a potential therapeutic agent for the non-small cell lung cancer.

Induction of apoptosis and inhibition of cell growth by tbx5 knockdown contribute to dysmorphogenesis in Zebrafish embryos

Background

The tbx5 mutation in human causes Holt-Oram syndrome, an autosomal dominant condition characterized by a familial history of congenital heart defects and preaxial radial upper-limb defects. We report aberrant apoptosis and dormant cell growth over head, heart, trunk, fin, and tail of zebrafish embryos with tbx5 deficiency correspond to the dysmorphogenesis of tbx5 morphants.

Methods

Wild-type zebrafish embryos at the 1-cell stage were injected with 4.3 nl of 19.4 ng of tbx5 morpholino or mismatch-tbx5-MO respectively in tbx5 morphants and mismatched control group. Semi-quantitative RT-PCR was used to for expression analysis of apoptosis and cell cycle-related genes. TUNEL and immunohistochemical assay showed the apoptosis spots within the local tissues. Ultra-structure of cardiac myocardium was examined by transmission electron microscope.

Results

Apoptosis-related genes (bad, bax, and bcl2), and cell cycle-related genes (cdk2, pcna, p27, and p57) showed remarkable increases in transcriptional level by RT-PCR. Using a TUNEL and immnuohistochemical assay, apoptosis was observed in the organs including the head, heart, pectoral fins, trunk, and tail of tbx5 knockdown embryos. Under transmission electron microscopic examination, mitochondria in cardiomyocytes became swollen and the myocardium was largely disorganized with a disarrayed appearance, compatible with reduced enhancement of myosin in the cardiac wall. The ATP level was reduced, and the ADP/ATP ratio as an apoptotic index significantly increased in the tbx5 deficient embryos.

Conclusion

Our study highlighted that tbx5 deficiency evoked apoptosis, distributed on multiple organs corresponding to dysmorphogenesis with the shortage of promising maturation, in tbx5 knockdown zebrafish embryos. We hypothesized that mesenchymal cell apoptosis associated with altered TBX5 level may subsequently interfered with organogenesis and contributed to dysmorphogenesis in tbx5 deficiency zebrafish embryos.

The gap junction as a "Biological Rosetta Stone": implications of evolution, stem cells to homeostatic regulation of health and disease in the Barker hypothesis

The discovery of the gap junction structure, its functions and the family of the "connexin" genes, has been basically ignored by the major biological disciplines. These connexin genes code for proteins that organize to form membrane-associated hemi-channels, "connexons", co-join with the connexons of neighboring cells to form gap junctions. Gap junctions appeared in the early evolution of the metazoan. Their fundamental functions, (e.g., to synchronize electrotonic and metabolic functions of societies of cells, and to regulate cell proliferation, cell differentiation, and apoptosis), were accomplished via integrating the extra-cellular triggering of intra-cellular signaling, and therefore, regulating gene expression. These functions have been documented by genetic mutations of the connexin genes and by chemical modulation of gap junctions. Via genetic alteration of connexins in knock-out and transgenic mice, as well as inherited connexin mutations in various human syndromes, the gap junction has been shown to be directly linked to many normal cell functions and multiple diseases, such as birth defects, reproductive, neurological disorders, immune dysfunction and cancer. Specifically, the modulation of gap junctional intercellular communication (GJIC), either by increasing or decreasing its functions by non-mutagenic chemicals or by oncogenes or tumor suppressor genes in normal or "initiated" stem cells and their progenitor cells, can have a major impact on tumor promotion or cancer chemoprevention and chemotherapy. The overview of the roles of the gap junction in the evolution of the metazoan and its potential in understanding a "systems" view of human health and aging and the diseases of aging will be attempted.

Nigella sativa: reduces the risk of various maladies

Coinage of terms like nutraceuticals, functional, and pharma foods has diverted the attention of human beings to where they are seeking more natural cures. Though pharmaceutical drugs have been beneficial for human health and have cured various diseases but they also impart some side effects. Numerous plants have been tested for their therapeutic potential; Nigella sativa, commonly known as black cumin, is one of them. It possesses a nutritional dense profile as its fixed oil (lipid fraction), is rich in unsaturated fatty acids while essential oil contains thymoquinone and carvacrol as antioxidants. N. sativa seeds also contain proteins, alkaloids (nigellicines and nigelledine), and saponins (alpha-hederin) in substantial amounts. Recent pharmacological investigations suggested its potential role, especially for the amelioration of oxidative stress through free radical scavenging activity, the induction of apoptosis to cure various cancer lines, the reduction of blood glucose, and the prevention of complications from diabetes. It regulates hematological and serological aspects and can be effective in dyslipidemia and respiratory disorders. Moreover, its immunopotentiating and immunomodulating role brings balance in the immune system. Evidence is available supporting the utilization of Nigella sativa and its bioactive components in a daily diet for health improvement. This review is intended to focus on the composition of Nigella sativa and to elaborate its possible therapeutic roles as a functional food to prevent an array of maladies.

A paradigm shift is required for the risk assessment of potential human health after exposure to low level chemical exposures: a response to the toxicity testing in the 21st century report

Chemicals are known to be associated with birth defects, cancer, cardiovascular diseases, immunological, reproductive, and neurological disorders. In response to recent reviews of limitations of current concepts and techniques for toxicity testing, this commentary challenges the paradigm that chemicals are directly responsible for DNA damage in the genomic-nuclear DNA in relevant cells of the human body. This challenge is not that mutations do not play roles in human-inherited or somatic diseases but that chemical exposures bring about disease end points by epigenetic mechanisms or by alterations in adult stem cell numbers in utero (ie, the Barker hypothesis) or postnatally, by selecting preexisting mutated cells. Classic concepts, that is, multistage, multimechanism process of carcinogenesis, stem cell theory of cancer, and newer and ignored concepts, such as cancer stem cells and cell-cell communication, will be used to support the view that the toxic effect of chemicals is mediated by nonmutagenic mechanisms at human relevant exposures.

The anticancer effects of actinoporin RTX-A from the sea anemone Heteractis crispa (=Radianthus macrodactylus)

Four isoforms of actinoporins were isolated in 2002-2004 from the tropical sea anemone Heteractis crispa (=Radianthus macrodactylus). Their potent hemolytic activities and effects on Ehrlich ascites carcinoma bearing mice were also studied. In this study, the individual actinoporin (RTX-A) demonstrated potential cancer-preventive activity at extremely low and non-cytotoxic concentrations. The substance suppressed the malignant transformation of mouse JB6 P(+) Cl41 cells stimulated by epidermal growth factor (EGF) in soft agar with the inhibition of number of the colonies C(50) (INCC(50))=0.034 nM. Actinoporin RTX-A also was shown to inhibit the phenotype expression of HeLa human cancer cells with an INCC(50)=0.03 nM. The cytotoxic effect of RTX-A against JB6 P(+) Cl41 cells and HeLa, THP-1, MDA-MB-231, and SNU-C4 human tumor cell lines was high (IC(50)=0.57, 2.26, 1.11, 30.0 and 4.66 nM), but significantly less than their capacity to suppress tumor cell colony formation or phenotype expression. RTX-A also induced apoptosis and inhibited basal AP-1, NF-kappaB, and p53-dependent transcriptional activity in JB6 Cl41 cells. These results confirmed that actinoporin RTX-A from H. crispa, at least partially, might exhibit cancer-preventive and anticancer cytotoxic properties through the induction of p53-independent apoptosis and inhibition of the oncogenic AP-1 and NF-kappaB nuclear factors activity.

Resveratrol and quercetin cooperate to induce senescence-like growth arrest in C6 rat glioma cells

Glioma is the most frequent and malignant primary human brain tumor with dismal prognosis despite multimodal therapy. Resveratrol and quercetin, two structurally related and naturally occurring polyphenols, are proposed to have anticancer effects. We report here that resveratrol and quercetin decreased the cell number in four glioma cell lines but not in rat astrocytes. Low doses of resveratrol (10 microM) or quercetin (25 microM) separately had no effect on apoptosis induction, but had a strong effect on caspase 3/7 activation when administered together. Western blot analyses showed that resveratrol (10 microM) and quercetin (25 microM) caused a reduction in phosphorylation of Akt, but this reduction was not sufficient by itself to mediate the effects of these polyphenols. Most important, resveratrol and quercetin chronically administered presented a strong synergism in inducing senescence-like growth arrest. These results suggest that the combination of polyphenols can potentialize their antitumoral activity, thereby reducing the therapeutic concentration needed for glioma treatment.

p53 Cooperates berberine-induced growth inhibition and apoptosis of non-small cell human lung cancer cells in vitro and tumor xenograft growth in vivo

Berberine has been shown to have anti-carcinogenic effects. Since p53 is the most commonly mutated tumor suppressor gene, and a lack of functional p53 is associated with an increased risk of cancer development, we examined the effects of berberine on p53-positive and p53-deficient non-small cell human lung cancer cells in vitro and in vivo. Treatment of A549, which express wild-type p53, and H1299, which are p53-deficient, human lung cancer cells with berberine resulted in inhibition of cell proliferation and an increase in apoptotic cell death; however, A549 cells were more sensitive to the berberine-induced cytotoxic effects than H1299 cells. Further, the treatment of A549 cells with pifithrin-alpha, a specific inhibitor of p53, or transfection of A549 cells with a p53 antisense oligodeoxynucleotide resulted in a reduction in the berberine-induced inhibition of cell proliferation and apoptosis. The berberine-induced apoptosis of both the A549 and H1299 human lung cancer cells was associated with the disruption of mitochondrial membrane potential, reduction in the levels of Bcl-2, Bcl-xl while increase in Bax, Bak, and activation of caspase-3. Treatment of the cells with pan-caspase inhibitor (z-VAD-fmk) or caspase-3 inhibitor (z-DEVD-fmk) inhibited berberine-induced apoptosis, thus suggesting the role of caspase-3. Further, the administration of berberine by oral gavage inhibited the growth of s.c. A549 and H1299 lung tumor xenografts in athymic nude mice, however, the growth of tumor xenograft of H1299 cells was faster than A549 cells in mice and the chemotherapeutic effect of berberine was more pronounced in the p53-positive-A549 tumor xenograft than p53-deficient-H1299 tumor xenograft.

The regulation of the gap junction of human mesenchymal stem cells through the internalization of quantum dots

The delivery mechanism of CdSe/ZnS quantum dots (QDs) into cells was previously found to critically determine the biocompatibility of QDs to human adult mesenchymal stem cells, but the associated mechanism remained unknown. The present study tried to establish a link between the above phenomenon and the change in gap junction upon QD internalization. By comparing Pep-1- and PolyFect-mediated QD internalizations, the connexin 43 (Cx43)-mediated gap junction intercellular communication (GJIC) of human adipose-derived adult stem cells was investigated in monolayer and in three-dimensional (3D) culture (alginate hollow spheres). The latter system offered cells more mobility, which was more similar as in vivo. The results showed that Pep-1-coated QDs, which escaped from the endo-/lysosome degradation, could activate the F-actin assembly and the ERK-dependent phosphorylation of Cx43. The consequence was a reduction in Cx43-mediated GJIC. When the cells were grown in high density 3D alginate hollow spheres instead of in monolayer, the decrease of GJIC caused by the QD internalization was restored. These results indicated that the adaptability in QDs-mediated regulation of GJIC with different delivery coatings depended on the culture systems. The study also suggested that the regulation of gap junction may play a key role in QD cytotoxicity.

Cytotoxicity of HC Orange NO. 1 to L929 fibroblast cells

HC Orange No. 1 (HCO1, 2-nitro-4'-hydroxydiphenylamine) (CAS No. 54381-08-7) is used as a colorant in commercial hair dyes. The cytotoxicity of HCO1 to L929 mouse connective tissue fibroblast cells was determined by use of a battery of endpoints that included electron transport activity determined by the MTT assay and fluorescence microscopy with Hoechst 33258, DNA agarose gel electrophoresis detected by ethidium bromide and flow cytometry. Cytotoxicity of HCO1 was found to be concentration- and time-dependent with EC(50) values of 28.0 and 12.0mg/L after 24h or 48h exposure, respectively. The mechanism of toxicity of HCO1 was more characteristic of necrosis than apoptosis. These results can be used to evaluate the relative in vitro toxicity of other dyes and to elucidate their mechanisms of toxicity so that accurate assessment of risks to humans can be made, especially from dermal exposure.

Functional characterization of a human aquaporin 0 mutation that leads to a congenital dominant lens cataract

The aquaporin (AQP) transmembrane proteins facilitate the movement of water across the plasma membrane. In the lens, AQP0 is expressed in fiber cells and AQP1 in the epithelium. Recently, two individuals were identified with congenital polymorphic autosomal dominant cataract, due to a single nucleotide base deletion mutation in the lens AQP0. The deletion modified the reading frame resulting in the addition of a premature stop codon. In the present study, we examined the water permeability properties, trafficking and dominant negative effects as well as cytotoxicity due to the mutant AQP0 (Delta213-AQP0) protein. The membrane water permeability (P(w)) of Delta213-AQP0 expressing oocytes (14+/-1 microm/s) was significantly lower than those expressing WT-AQP0 (25+/-3 microm/s). P(w) of water injected control oocytes was 13+/-2 microm/s. Co-expression of WT-AQP0 with Delta213-AQP0 significantly lowered the P(w) (18+/-3 microm/s) compared to WT-AQP0. With or without the EGFP tag, WT-AQP0 protein localized in the plasma membranes of oocytes and cultured cells whereas Delta213-AQP0 was retained in the ER. Forster Resonance Energy Transfer (FRET) showed that WT-AQP0 partly localized with the co-expressed Delta213-AQP0. Co-localization studies suggest that the mutant AQP0 gained its dominant function by trapping the WT-AQP0 in the ER through hetero-oligomerization. Incubating the cells with chemical chaperones, namely, TMAO and DMSO, did not correct the folding/trafficking defects. Cell death in the Delta213-AQP0 expressing cells was due to necrosis caused by the accumulation of Delta213-AQP0 protein in the ER in cytotoxic proportions. The data show that replacement of the distal end of the 6th TM domain and the C-terminal domain of AQP0 due to the deletion mutation resulted in the impairment of cell membrane P(w), localization of the mutant protein in the ER without trafficking to the plasma membrane, and cytotoxicity due to the accumulation of the mutant protein. Cataracts in patients with this mutation might have resulted from the above mentioned consequences.