Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.22.62 (caspase-9)
 7,507 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We have previously shown that arsenic trioxide blocks proliferation and induces apoptosis in human pancreatic cancer cells at low, non-toxic concentrations. The mechanisms of the apoptosis was investigated in MiaPaCa2 and PANC-1 cells that have been previously shown to be responsive to arsenic trioxide. The results show the caspase-3, caspase-7, and caspase-9 are all activated by arsenic trioxide, together with cleavage of the downstream caspase-3 target poly ADP ribose polymerase (PARP). Expression of the anti-apoptosis proteins, Bcl-2 and Mcl-1 expression decreased time-dependently while Bax expression increased. These findings indicate that the Bcl family of proteins, the mitochondrial pathway and activation of the caspase cascade are responsible for arsenic-induced apoptosis. Flow cytometric analysis revealed changes of cell cycle distribution from a G0/G1 phase arrest at 24 hours to G2/M phase arrest at 72 hours following arsenic treatment. The sub-G0/G1 cell population of apoptotic cells was increased at these times. Arsenic increased expression of the P21 protein and decreased levels of cyclin A, cyclin B1 and cyclin D1, but expression of CDK2, CDK4, CDK6, and cyclin E were not affected. Arsenic trioxide markedly enhanced the expression of GADD45 and GADD153 in a time-dependent manner. In summary, arsenic trioxide induced apoptosis in pancreatic cancer cells through activating the caspase cascade via the mitochondrial pathway, GADD expression and by modifying cell cycle progress and changes in several cycle-regulating proteins. This old drug may be valuable for treatment of pancreatic cancer.
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PMID:Arsenic trioxide induces apoptosis in pancreatic cancer cells via changes in cell cycle, caspase activation, and GADD expression. 1288 67

Chronic arsenic poisoning is a world public health issue. Long-term exposure to inorganic arsenic (As) from drinking water has been documented to induce cancers in lung, urinary bladder, kidney, liver and skin in a dose-response relationship. Oxidative stress, chromosomal abnormality and altered growth factors are possible modes of action in arsenic carcinogenesis. Arsenic tends to accumulate in the skin. Skin hyperpigmentation and hyperkeratosis have long been known to be the hallmark signs of chronic As exposure. There are significant associations between these dermatological lesions and risk of skin cancer. The most common arsenic-induced skin cancers are Bowen's disease (carcinoma in situ), basal cell carcinoma (BCC) and squamous cell carcinoma (SCC). Arsenic-induced Bowen's disease (As-BD) is able to transform into invasive BCC and SCC. Individuals with As-BD are considered for more aggressive cancer screening in the lung and urinary bladder. As-BD provides an excellent model for studying the early stages of chemical carcinogenesis in human beings. Arsenic exposure is associated with G2/M cell cycle arrest and DNA aneuploidy in both cultured keratinocytes and As-BD lesions. These cellular abnormalities relate to the p53 dysfunction induced by arsenic. The characteristic clinical figures of arsenic-induced skin cancer are: (i) occurrence on sun-protected areas of the body; (ii) multiple and recrudescent lesions. Both As and UVB are able to induce skin cancer. Arsenic treatment enhances the cytotoxicity, mutagenicity and clastogenicity of UV in mammalian cells. Both As and UVB induce apoptosis in keratinocytes by caspase-9 and caspase-8 signaling, respectively. Combined UVB and As treatments resulted in the antiproliferative and proapoptotic effects by stimulating both caspase pathways in the keratinocytes. UVB irradiation inhibited mutant p53 and ki-67 expression, as well as increased in the number of apoptotic cells in As-BD lesions which resulted in an inhibitory effect on proliferation. As-UVB interaction provides a reasonable explanation for the rare occurrences of arsenical cancer in the sun-exposed skin. The multiple and recurrent skin lesions are associated with cellular immune dysfunction in chronic arsenism. A decrease in peripheral CD4+ cells was noticed in the inhabitants of arsenic exposure areas. There was a decrease in the number of Langerhans cells in As-BD lesion which results in an impaired immune function on the lesional sites. Since CD4+ cells are the target cell affected by As, the interaction between CD4+ cells and epidermal keratinocytes under As affection might be closely linked to the pathogenesis of multiple occurrence of arsenic-induced skin cancer. In this review, we provide and discuss the pathomechanisms of arsenic skin cancer and the relationship to its characteristic figures. Such information is critical for understanding the molecular mechanism for arsenic carcinogenesis in other internal organs.
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PMID:Arsenic carcinogenesis in the skin. 1680 64

Arsenic exists widely in rock, water and air, and arsanilic acid (also known as aminophenyl arsenic acid) is an organoarsenic compound and has been used as feed additives. Organoarsenic compounds in foodstuff cause adverse effects, including acute and chronic toxicity, in animals and humans. However, little is known about the cellular toxicity and mechanisms of organic arsenic on the kidney. In this study, we explored the toxicity and molecular mechanisms of arsanilic acid on rat kidney epithelial cells (NRK-52e cells). The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay showed that arsanilic acid inhibited the proliferation of rat NRK-52e cells in a dose-dependent manner, and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling assay and flow cytometry revealed that arsanilic acid induced cellular apoptosis in NRK-52e cells. Fluorescence spectrophotometer displayed that arsanilic acid caused a loss of mitochondrial transmembrane potential (MMP) of NRK-52e cells, but enhanced reactive oxygen species level of these cells. Notably, trolox, a water-soluble derivative of vitamin E, protected NRK-52e cells against MMP loss and apoptosis caused by arsanilic acid. Western blots with caspase inhibitors further indicated that arsanilic acid increased expression of active caspase-3 and -9 in NRK-52e cells. Collectively, these results suggest that arsanilic acid causes apoptosis and oxidative stress in rat kidney epithelial cells through activation of the caspase-9 and -3 signaling pathway. This study thus provides a novel insight into molecular mechanisms by which arsanilic acid has adverse cytotoxicity on renal tubular epithelial cells.
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PMID:Arsanilic acid causes apoptosis and oxidative stress in rat kidney epithelial cells (NRK-52e cells) by the activation of the caspase-9 and -3 signaling pathway. 2384 44

Arsenic (As), cadmium (Cd), and lead (Pb) in select combinations are proved to affect the viability of astrocyte. However, their role in glioma, an aggressive astroglial tumor, is unexplored. We analyzed the effect of As+Cd+Pb on C6-glioma cells derived from rat glioma. We determined the lethal concentration (LC) of individual metal, and then treated C6-glioma cells with As+Cd+Pb at LC-5 (As: 5 mM, Cd: 2.5 mM and Pb: 15 mM), and concentrations that were double or triple of LC5. As+Cd+Pb induced dose-dependent reduction in C6-glioma viability. Cell death was due to apoptotic DNA fragmentation, detected through terminal deoxynucleotidyl transferase-mediated dUTP-nick-end labeling. An enhanced cleavage of caspase-9 indicated the apoptosis to be mitochondria-mediated. An increase in pro-apoptotic Bcl-2-associated-X protein (Bax) and decrease in anti-apoptotic Bcl2 resulting in a Bax/Bcl2 ratio > 1.0 validated mitochondrial apoptosis. Exploring apoptotic regulatory mechanism revealed an alteration in glial cell morphology and augmentation of astroglial marker, glial fibrillary acidic protein (GFAP), that demonstrated co-localization with cleaved caspase-9. The glial activation was accompanied by inflammation, involving the up-regulation of interleukin-1 (IL-1) and IL-1-receptor. IL-1 also contributed to apoptosis, as evident from the attenuation of cleaved caspase-9 upon treatment with IL-1receptor antagonist. Investigating the involvement of Mitogen-activated protein kinases (MAPKs) revealed the activation of P38 as indicated by an increased phospho-p38 expression. p38-MAPK inhibitor, SB203580, prevented caspase-9 activation, which further suppoted the involvement of p38-MAPK in C6-glioma apoptosis. Overall our data demonstrate the toxic effect of As+Cd+Pb on C6-glioma, which is mediated by mitochondria-dependent apoptosis that requires astroglial activation, inflammation and p38-MAPK signaling. As+Cd+Pb combination treatment may have a potential therapeutic usage against glial tumors.
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PMID:Optimized mixture of As, Cd and Pb induce mitochondria-mediated apoptosis in C6-glioma via astroglial activation, inflammation and P38-MAPK. 2639 15

Arsenic-based drugs as food additive were used in poultry. However, excessive arsenic exposure can disturb myocardial cell metabolism, which results in the inhibition of growth and development of chickens. Since disordered mitochondria influences cardiac physiology and pathology, a better understanding of the mechanisms modulating cardiomyocyte mitochondria process is critical for identifying the potent detoxication targets under arsenic exposure in chickens. Male Hy-line chickens (1-day-old) were fed either a basal diet or an arsenic trioxide (As2O3)-supplemented diet containing 7.5, 15, and 30 mg/kg As2O3 for 90 d. The concentrations of ions ([Na, Mg, Al, Si, K, Ca, As, Mn, Fe, Zn] and [Cr, Ni, Cu, Ba]) significantly increased and decreased in the heart of chicken under As2O3 exposure, respectively. Moreover, we observed that As2O3 decreased high-density lipoprotein cholesterol concentrations and increased total cholesterol concentrations in the serum. We also observed arterial wall degeneration, biochemical character of mitochondria undergoing either fission or fusion, typical apoptotic cells, typical DNA fragments and TdT-mediated dUTP nick end labeling positive nuclei under As2O3 exposure in the heart. Further quantitative real-time PCR demonstrated that B cell lymphoma/leukemia 2 (Bcl2) were significantly decreased and dynamin-related protein 1 (Drp1), Optic atrophy 1 (Opa1), mitochondrial fission factor 1 (Mfn1), Mfn2, p53, caspase-8, Bcl-2 associated X protein (Bax), caspase-3, caspase-9 and cytochrome C were significantly increased in all As2O3 group. In conclusion, As2O3 can disturb the trace elements homeostasis, which might favor the development of mitochondrial damage. Moreover, we suspected that As2O3-increased mitochondrial dynamics might trigger the apoptosis to limit cell metabolism. These features might identify the role of the mitochondrial dynamics under arsenic-induced cardiovascular disease in the chickens.
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PMID:Arsenic-induced cardiotoxicity correlates with mitochondrial damage and trace elements imbalance in broiler chickens. 3033 49