Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P42574 (caspase-3)
 45,978 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Cyclooxygenase-2 (COX-2) inhibition can inhibit UVB-induced carcinogenesis in the skin. We have shown that COX-2 is overexpressed in UVB-induced squamous cell carcinomas (SCCs). Celecoxib, a specific inhibitor of COX-2, blocks UVB-induced papillomas and carcinomas in murine skin. However, as COX-2 inhibitors of this type are associated with an increased risk of adverse cardiovascular events, we decided to study nimesulide, a different class of COX-2 inhibitor, an N-arylmethanesulfonamide derivative not known to have these untoward effects. To assess the antitumor-promoting effects of nimesulide, 90 mice were equally divided into three groups. Group I animals received no test agent or UVB and served as age-matched controls; group II animals were irradiated with UVB (180 mJ cm(-2), twice weekly for 35 weeks) and group III animals received 300 p.p.m. nimesulide in drinking water and were irradiated with UVB as described for group-II. Nimesulide treatment reduced the growth of UVB-induced tumors both in terms of tumor number and tumor volume. By weeks 25, 30 and 35, the tumor numbers in the nimesulide-treated group were 79%, 49% and 53% less than the number occurring in UVB-treated animals whereas tumor volume was reduced 69%, 54% and 53%, respectively, compared to the UVB-irradiated control group. Nimesulide also inhibited the malignant progression of SCCs. The reduction in tumorigenesis was paralleled by a decrease in cell cycle regulatory proteins (cyclins A, B1, D1, E, CDK2/4/6) and the antiapoptotic protein (Bcl2); concomitantly there was an increase in proapoptotic markers, poly (ADP-ribose) polymerase (PARP) and caspase-3. Nimesulide also decreased ornithine decarboxylase expression and the nuclear accumulation of nuclear factor kappa B transcriptionally active protein complexes. These results show that alternative classes of COX-2 inhibitors may likely be efficacious as cancer chemopreventive agents and may have an improved therapeutic index.
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PMID:Cyclooxygenase-2 inhibitor nimesulide blocks ultraviolet B-induced photocarcinogenesis in SKH-1 hairless mice. 1826 22

Although flavopiridol, a semisynthetic flavone, was initially thought to be a specific inhibitor of cyclin-dependent kinases, it has now been shown that flavopiridol mediates antitumor responses through mechanism(s) yet to be defined. We have shown previously that flavopiridol abrogates tumor necrosis factor (TNF)-induced nuclear factor-kappaB (NF-kappaB) activation. In this report, we examined whether this flavone affects other cellular responses activated by TNF. TNF is a potent inducer of activator protein-1 (AP-1), and flavopiridol abrogated this activation in a dose- and time-dependent manner. Flavopiridol also suppressed AP-1 activation induced by various carcinogens and inflammatory stimuli. When examined for its effect on other signaling pathways, flavopiridol inhibited TNF-induced activation of various mitogen-activated protein kinases, including c-Jun NH(2)-terminal kinase (JNK), p38 mitogen-activated protein kinase (MAPK), and p44/p42 MAPK. It is noteworthy that this flavone also suppressed TNF-induced activation of Akt, a cell survival kinase, and expression of various antiapoptotic proteins, such as IAP-1, IAP-2, XIAP, Bcl-2, Bcl-xL, and TRAF-1. Flavopiridol also inhibited the TNF-induced induction of intercellular adhesion molecule-1, c-Myc, and c-Fos, all known to mediate tumorigenesis. Moreover, TNF-induced apoptosis was enhanced by flavopiridol through activation of the bid-cytochrome-caspase-9-caspase-3 pathway. Overall, our results clearly suggest that flavopiridol interferes with the TNF cell-signaling pathway, leading to suppression of antiapoptotic mechanisms and enhancement of apoptosis.
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PMID:Flavopiridol suppresses tumor necrosis factor-induced activation of activator protein-1, c-Jun N-terminal kinase, p38 mitogen-activated protein kinase (MAPK), p44/p42 MAPK, and Akt, inhibits expression of antiapoptotic gene products, and enhances apoptosis through cytochrome c release and caspase activation in human myeloid cells. 2730 81

Molecular targeting for apoptosis induction is being developed for better treatment of cancer. Downregulation of 15-lipoxygenase-1 (15-LOX-1) is linked to colorectal tumorigenesis. Re-expression of 15-LOX-1 in cancer cells by pharmaceutical agents induces apoptosis. Antitumorigenic agents can also induce apoptosis via other molecular targets. Whether restoring 15-LOX-1 expression in cancer cells is therapeutically sufficient to inhibit colonic tumorigenesis remains unknown. We tested this question using an adenoviral delivery system to express 15-LOX-1 in in vitro and in vivo models of colon cancer. We found that (i) the adenoviral vector 5/3 fiber modification enhanced 15-LOX-1 gene transduction in various colorectal cancer cell lines, (ii) the adenoviral vector delivery restored 15-LOX-1 expression and enzymatic activity to therapeutic levels in colon cancer cell lines, and (iii) 15-LOX-1 expression downregulated the expression of the antiapoptotic proteins X-linked inhibitor of apoptosis protein (XIAP) and BcL-XL, activated caspase-3, triggered apoptosis, and inhibited cancer cell survival in vitro and the growth of colon cancer xenografts in vivo. Thus, selective molecular targeting of 15-LOX-1 expression is sufficient to re-establish apoptosis in colon cancer cells and inhibit tumorigenesis. These data provide the rationale for further development of therapeutic strategies to target 15-LOX-1 molecularly for treating colonic tumorigenesis.
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PMID:Therapeutic molecular targeting of 15-lipoxygenase-1 in colon cancer. 1838 20

Di (2-ethylhexyl) phthalate (DEHP) exposure is thought to lead to hepatocellular hypertrophy and hyperplasia in rodents mediated via peroxisome proliferator-activated receptor alpha (PPAR alpha). A recent study revealed that long-term exposure to relatively low-dose DEHP (0.05%) caused liver tumors including hepatocellular carcinomas, hepatocellular adenomas, and chologiocellular carcinomas at a higher incidence in Ppar alpha-null mice (25.8%) than in wild-type mice (10.0%). Using tissues with hepatocellular adenoma, microarray (Affymetrix MOE430A) as well as, in part, real-time quantitative PCR analysis was conducted to elucidate the mechanisms of the adenoma formation resulting from DEHP exposure in both genotyped mice. The microarray profiles showed that the up- or down-regulated genes were quite different between hepatocellular adenoma tissues of wild-type and Ppar alpha-null mice exposed to DEHP. The gene expressions of apoptotic peptidase activating factor 1 (Apaf1) and DNA-damage-inducible 45 alpha (Gadd45a) were increased in the hepatocellular adenoma tissues of wild-type mice exposed to DEHP, whereas they were unchanged in corresponding tissues of Ppar alpha-null mice. On the other hand, the expressions of cyclin B2 and myeloid cell leukemia sequence 1 were increased only in the hepatocellular adenoma tissues of Ppar alpha-null mice. Taken together, DEHP may induce hepatocellular adenomas, in part, via suppression of G2/M arrest regulated by Gadd45a and caspase 3-dependent apoptosis in Ppar alpha-null mice, but these genes may not be involved in tumorigenesis in the wild-type mice. In contrast, the expression level of Met was notably increased in the liver adenoma tissue of wild-type mice, which may suggest the involvement of Met in DEHP-induced tumorigenesis in wild-type mice.
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PMID:Different mechanisms of DEHP-induced hepatocellular adenoma tumorigenesis in wild-type and Ppar alpha-null mice. 1840 68

A hallmark of cancer cells is their ability to evade apoptosis and mitochondria play a critical role in this process. Delineating mitochondrial differences between normal and cancer cells has proven challenging due to the lack of matched cell lines. Here, we compare two matched liver progenitor cell (LPC) lines, one non-tumorigenic [p53-immortalized liver (PIL) 4] and the other tumorigenic (PIL2). Analysis of these cell lines and a p53 wild-type non-tumorigenic cell line [bipotential murine oval liver (BMOL)] revealed an increase in expression of genes encoding the antiapoptotic proteins cellular inhibitor of apoptosis protein (cIAP) 1 and yes associate protein in the PIL2 cells, which resulted in an increase in the protein encoded by these genes. PIL2 cells have higher mitochondrial membrane potential (Deltapsi(m)) compared with PIL4 and BMOL and had greater levels of reactive oxygen species, despite the fact that the mitochondrial antioxidant enzyme, manganese superoxide disumutase, was elevated at transcript and protein levels. Taken together, these results may account for the observed resistance of PIL2 cells to apoptotic stimuli compared with PIL4. We tested a new gold compound to show that hyperpolarized Deltapsi(m) led to its increased accumulation in mitochondria of PIL2 cells. This compound selectively induces apoptosis in PIL2 cells but not in PIL4 or BMOL. The gold compound depolarized the Deltapsi(m), depleted the adenosine triphosphate pool and activated caspase-3 and caspase-9, suggesting that apoptosis was mediated via mitochondria. This investigation shows that the non-tumorigenic and tumorigenic LPCs are useful models to delineate the role of mitochondrial dysfunction in tumorigenesis and for the future development of mitochondria-targeted chemotherapeutics that selectively target tumor cells.
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PMID:Bioenergetic differences selectively sensitize tumorigenic liver progenitor cells to a new gold(I) compound. 1841 65

Sarcotriol (ST) has been shown to be chemopreventive on 7,12-dimethyl-benz(a)anthracene (DMBA) initiated and 12-O-tetradecanoylphorbol-13-acetate (TPA)-promoted skin tumor development in CD-1 mice in recent studies from our laboratory. The objective of this study was to determine the chemopreventive effects of ST on ultraviolet B (UVB)-induced skin tumor development in female SKH-1 hairless mice, an experimental model relevant to human skin cancer development, and its possible mechanisms of action. Female SKH-1 mice were divided into two groups: Control and ST treated. Control was topically treated with 100 microliter acetone and ST treated group administered with 30 microgram ST in 100 microliter acetone one hour before UVB exposure. For UVB-induced tumorigenesis, carcinogenesis was initiated and promoted by UVB (180 mJ/cm(2)). Group weights and tumor counts were taken once every week. After 30 weeks, mice were sacrificed and dorsal skin samples were collected. The proteins from the skin sample were further used for SDS-PAGE and Western blotting using specific antibodies against caspase-3, caspase-8, caspase-9 and p53. Tumor multiplicity was found 19.6, 5.2 in the control and ST treated groups respectively. Caspase-3, -8, -9 and p53 were significantly (P < 0.05) upregulated in ST treated group compared to Control group. Together, this study for the first time identifies the chemopreventive effects of ST in UVB-induced carcinogenesis possibly by inducing apoptosis and upregulating p53.
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PMID:Chemopreventive effects of sarcotriol on ultraviolet B-induced skin tumor development in SKH-1 hairless mice. 1846 28

Brahma-related gene 1 (BRG1) is a catalytic subunit of the switch in mating type/sucrose nonfermentation complex and plays an important role in cancer development. Mouse homozygous knockout experiments testing the role of BRG1 in tumorigenesis have been hampered because BRG1 inactivation is embryonic lethal. To bypass this constraint, we developed a lung-specific conditional knockout of BRG1 and examined the effect of BRG1 inactivation in an ethyl carbamate lung carcinogenesis mouse model. We found that the heterozygous loss of BRG1 resulted in increases in both the number and size of tumors when compared with controls. In contrast, when both BRG1 alleles were inactivated, neither the number nor the size of tumors increased compared with controls. In mouse lung tissue where BRG1 was homozygously inactivated, immunostaining for apoptotic markers showed significant increase in Apo-BrdUrd and cleaved caspase-3. These data indicate that a loss of cell viability underlies why biallelic inactivation of BRG1 does not increase tumorigenesis. We also examined mice when exposed to the carcinogen ethyl carbamate and then subjected to BRG1 inactivation. In these cells, loss of BRG1 after carcinogen exposure potentiated tumor development. A subset of tumors retained BRG1 expression, whereas others showed either partial or complete loss of BRG1 expression. Tumors completely devoid of BRG1 expression were significantly larger and expressed higher levels of two markers of proliferation, proliferating cell nuclear antigen and Ki67. Although biallelic inactivation of BRG1 could not initiate tumor development in untransformed cells, our results indicate that transformation and tumor progression are greatly affected by loss of BRG1.
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PMID:Targeted knockout of BRG1 potentiates lung cancer development. 1848 51

Epidemiological and experimental carcinogenesis studies provide evidence that certain components of garlic have anti-cancer activity. Although the biotransformed garlic derivative S-allylmercapto-L-cysteine (SAMC) has been reported to show an inhibitory effect on tumorigenesis, the mechanisms are poorly understood. The present study investigated the effect of SAMC on the growth of human gastric cancer SNU-1 cells. Upon treatment with SAMC, a concentration-dependent inhibition of cell proliferation was observed and cells developed many of the hallmark features of apoptosis, including DNA fragmentation and an increase in the sub-diploid population. The anti-proliferative and apoptotic effect of SAMC was associated with the induction of Bax, p53, and caspase-9, rather than the induction of Bcl-2 and p21. Mitochondrial cytochrome c activation and an in vitro caspase-3 activity assay demonstrated that the activation of caspases accompanies the apoptotic effect of SAMC, which mediates cell death. These results suggest that the apoptotic effect of SAMC on gastric cancer SNU-1 cells may be connected with caspase-3 activation through the induction of Bax and p53, rather then Bcl-2 and p21.
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PMID:Induction of apoptosis by S-allylmercapto-L-cysteine, a biotransformed garlic derivative, on a human gastric cancer cell line. 1850 70

Breast and ovarian cancer patients with germline mutations in BRCA1 respond more favorably to initial chemotherapy. We previously reported that cells from women carrying the BRCA1 185delAG founder mutation undergo an enhanced caspase-3-mediated apoptotic response. Here, we report on the transient and stable transfection of cDNA coding for the putative truncated protein product of the BRCA1 185delAG mutant gene into BRCA1 wild-type human ovarian surface epithelial cells and ovarian cancer cells, resulting in cells with a heterozygous background containing two BRCA1 wild-type alleles and the BRCA1 185delAG transcript. The BRCA1 185delAG truncation (BRAt) protein did not alter epithelial cell morphology or induce tumorigenesis. However, upon treatment with staurosporine, BRAt cells showed increased levels of active caspase-3 and increased cleavage of caspase-3 substrates, PARP and DFF45. Additionally, XIAP and cIAP-1 protein are at reduced levels in untreated BRAt cells as compared to control cells. BRAt also reduced levels of phosphorylated Akt and overexpression of activated Akt in BRAt cells restored caspase-3 activity to that seen in wild-type cells. Further, BRAt expression increased chemosensitivity in platinum-resistant ovarian cancer cells. Taken together, our data demonstrate that truncated proteins arising from BRCA1 185delAG mutation increase Akt-mediated apoptosis, suggesting a possible mechanism by which ovarian cancer patients with this germline BRCA1 mutation may respond better to initial chemotherapy.
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PMID:BRCA1 185delAG truncation protein, BRAt, amplifies caspase-mediated apoptosis in ovarian cells. 1859 35

The chemopreventive efficacy of turmeric has been established in experimental systems. However, its mechanism(s) of action are not fully elucidated in vivo. The present study investigates the mechanism of turmeric-mediated chemoprevention in 7,12-dimethylbenz(a)anthracene (DMBA)-induced hamster buccal pouch (HBP) carcinogenesis at 2, 4, 6, 10 and 12 weeks. Dietary turmeric (1%) led to decrease in DMBA-induced tumor burden and multiplicity, and enhanced the latency period in parallel, to its modulatory effects on oncogene products and various cellular responses during HBP tumorigenesis. DMBA-induced expression of ras oncogene product, p21 and downstream target, the mitogen-activated protein kinases were significantly decreased by turmeric during HBP carcinogenesis. Turmeric also diminished the DMBA-induced mRNA expression of proto-oncogenes (c-jun, c-fos) and NF-kappaB, leading to decreased protein levels and in further attenuation of DMBA-induced AP-1/NF-kappaB DNA-binding in the buccal pouch nuclear extracts. Besides, buccal pouch of hamsters receiving turmeric diet showed significant alterations in DMBA-induced effects: (a) decrease in cell proliferation (diminished PCNA and Bcl2 expression), (b) enhanced apoptosis (increased expression of Bax, caspase-3 and apoptotic index), (c) decrease in inflammation (levels of Cox-2, the downstream target of AP-1/NF-kappaB, and PGE2) and (d) aberrant expression of differentiation markers, the cytokeratins (1, 5, 8, and 18). Together, the protective effects of dietary turmeric converge on augmenting apoptosis of the initiated cells and decreasing cell proliferation in DMBA-treated animals, which in turn, is reflected in decreased tumor burden, multiplicity and enhanced latency period. Some of these biomarkers are likely to be helpful in monitoring clinical trials and evaluating drug effect measurements.
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PMID:Dietary turmeric modulates DMBA-induced p21ras, MAP kinases and AP-1/NF-kappaB pathway to alter cellular responses during hamster buccal pouch carcinogenesis. 1868 51


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