Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.4.2.30 (PARP)
 13,611 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Poly(ADP-ribose) polymerase (PARP), a nuclear enzyme that is catalytically activated by DNA strand breaks, plays a complex role in DNA repair. Using NAD(+) as a precursor, it catalyzes the formation of ADP-ribose polymers, which are attached to various proteins. Defects in DNA repair pathways have been associated with increased risks for cancer in humans. We investigated whether differences in the activity of PARP are associated with the risk for laryngeal cancer. In a case-control study on genetic, lifestyle and occupational risk factors for laryngeal cancer, PARP activity was assessed as DNA damage-induced poly(ADP-ribose) formation in human peripheral blood lymphocytes by quantitative immunofluorescence analysis. Polymer formation was determined as the cellular response to bleomycin, a well-known inducer of DNA strand breaks, in lymphocytes from 69 laryngeal cancer patients and 125 healthy controls. The frequency of bleomycin-induced polymer formation, measured as mean pixel intensity, was significantly lower in cases (74.6, SE = 3.7) than in controls (94.5, SE = 3.5) and not influenced by smoking, age or sex. There was no significant difference between cases (59.1, SE = 5.2) and controls (50.5, SE = 3.7) in basal polymer formation (in cells not treated with bleomycin). When the highest tertile of polymer formation was used as the reference, the odds ratio for the lowest tertile of bleomycin-induced polymer formation was 3.79 (95% confidence interval 1.37-10.47, p = 0.01). Peripheral blood lymphocytes from laryngeal cancer patients thus showed significantly less bleomycin-induced poly(ADP-ribose) formation. Our results suggest that a reduced capacity of somatic cells to synthesize poly(ADP-ribose) might be associated with an increased risk for laryngeal cancer. The underlying mechanism remains to be investigated.
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PMID:Reduced poly(ADP-ribosyl)ation in lymphocytes of laryngeal cancer patients: results of a case-control study. 1192 Jun 51

Previously, we designed a ribozyme that targets the H-ras oncogene at the 12th codon mutation site (Chang et al., 1997). Ribozymes have antisense molecule and site-specific ribonuclease potential. In this study, an adenoviral vector was used to transduce the H-ras ribozyme into laryngeal cancer cells (HEp-2). This served to downregulate the H-ras gene expression in which this ribozyme performed antisense activity due to HEp-2 cells containing wild-type alleles in the 12th H-ras codon. Together, our data demonstrated that the recombinant adenovirus encoding H-ras ribozyme can be broadly regarded as a cytotoxic gene therapy in laryngeal cancer cells regardless of containing wild-type or mutant ras gene. In addition, the mechanism through which the H-ras ribozyme inhibited tumor growth was apoptosis and involved both caspase- and mitochondria-mediated pathways. The activators caspase-8 and -9 as well as the effector caspase-3 in the induction phase of apoptosis and the substrate PARP of caspase-3 in the execution phase were activated 48h following the H-ras ribozyme treatment. Mitochondrial events characterized by the production of superoxide anion and the release of cytochrome c started at 24h. Mitochondrial transmembrane potential loss occurred 48h after the ribozyme treatment. However, Bcl-2 delayed cytochrome c release to the cytosol, but it could not protect the apoptosis effect, suggesting that cytochrome c release from mitochondria may not play a role in H-ras ribozyme-induced apoptosis.
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PMID:Recombinant adenovirus encoding H-ras ribozyme induces apoptosis in laryngeal cancer cells through caspase- and mitochondria-dependent pathways. 1241 27

Several studies have shown that nemo-like kinase (NLK) plays a vital role in apoptosis of cancer cells. The present research concerned effects and mechanisms of Taxol on NLK knockdown human laryngeal cancerHep-2 cell lines in vitro. Using RNAi, methyl-thiazoltetrazolium (MTT) assays, real-time RT-PCR, Western blotting and flow cytometry analysis, growth and the cell cycle progression of NLK knockdown Hep-2 cells and expression of downstream molecules were observed. Cell growth was obviously suppressed in the Taxol treated group (P<0.001, 48 hours). Cell numbers of combined Taxol-based chemotherapy with lentivirus mediated RNAi treatment group (Lv-shNLK+Taxol goup) were significantly different from NLK-specific siRNA lentivirus infected group (Lv-shNLK group) (p<0.001). Flow cytometry analysis revealed that Lv-shNLK+Taxol caused the G0/G1-phase DNA content to decrease from 44.1 to 3.33% (p<0.001) and the S-phase DNA content to increase from 38.4 to 82.0% (p<0.001), in comparison with the Lv-shNLK+Taxol group. Immunoblot analysis showed that knockdown of NLK led to significant reduction in the levels of cyclin D1, PCNA and PARP, whereas cyclin B1 was elevated in. Cell growth was also obviously suppressed in the Hep-2 cell line, knockdown of NLK making them more sensitive to Taxol treatment. NLK is expected to become a target of new laryngeal cancer gene therapies.
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PMID:Inhibition of nemo-like kinase increases taxol sensitivity in laryngeal cancer. 2446 Feb 65

To investigate the role of CUG-binding protein 1 (CUGBP1) in human laryngeal cancer, we employed lentivirus-mediated short hairpin RNA (shRNA) to knockdown CUGBP1 expression in Hep-2 cells. Depletion of CUGBP1 remarkably inhibited the proliferation of Hep-2 cells. CUGBP1 knockdown induced cell cycle arrest in S phase, especially in the sub-G1 phase, representing apoptotic cells. Knockdown of CUGBP1 in Hep-2 cells markedly increased the expression of LIP and cleavage of PARP, which could contribute to apoptosis. Thus CUGBP1 has a critical role in modulating cell growth and apoptosis, and serves as a potential therapeutic target in laryngeal cancer.
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PMID:Knockdown of CUG-binding protein 1 induces apoptosis of human laryngeal cancer cells. 2507 23

Natural products are among one of the most promising fields in finding new molecular targets in cancer therapy. Laryngeal carcinoma is one of the most common cancers affecting the head and neck regions, and is associated with high morbidity rate if left untreated. The aim of this study was to examine the antiproliferative effect of Araucaria angustifolia on laryngeal carcinoma HEp-2 cells. The results showed that A. angustifolia extract (AAE) induced a significant cytotoxicity in HEp-2 cells compared to the non-tumor human epithelial (HEK-293) cells, indicating a selective activity of AAE for the cancer cells. A. angustifolia extract was able to increase oxidative damage to lipids and proteins, and the production of nitric oxide, along with the depletion of enzymatic antioxidant defenses (superoxide dismutase and catalase) in the tumor cell line. Moreover, AAE was able to induce DNA damage, nuclear fragmentation and chromatin condensation. A significant increase in the Apoptosis Inducing Factor (AIF), Bax, poly-(ADP-ribose) polymerase (PARP) and caspase-3 cleavage expression were also found. These effects could be related to the ability of AAE to increase the production of reactive oxygen species through inhibition of the mitochondrial electron transport chain complex I activity and ATP production by the tumor cells. The phytochemical analysis of A. angustifolia, performed using High Resolution Mass Spectrometry (HRMS) in MS and MS/MS mode, showed the presence of dodecanoic and hexadecanoic acids, and phenolic compounds, which may be associated with the chemotherapeutic effect observed in this study.
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PMID:Mitochondria and redox homoeostasis as chemotherapeutic targets of Araucaria angustifolia (Bert.) O. Kuntze in human larynx HEp-2 cancer cells. 2577 Sep 32

Laryngeal cancer is one of the most common malignant tumors in the respiratory tumors, and its incidence ranks second highest in the respiratory tumors. Resveratrol (Res) is a kind of polyphenols, which can inhibit nucleotides can inhibit the growth of liver cancer cells, gastric cancer cells, pancreatic cells and other tumor cells by inhibiting ribonucleotide reductase in the cells. Taxol (Tax) is a kind of secondary metabolites of Taxus chinensis, which has anti-tumor activity for breast cancer, cervical cancer, ovarian cancer and other tumors by inhibiting cellular microtubule depolymerization. But at present the effects of resveratrol combined with taxol on human laryngeal carcinoma cell strain Hep-2 and their underlying molecular mechanisms are rarely reported. After human laryngeal cancer cell Hep-2 cells were processed with resveratrol (Res) and taxol (Tax), CCK-8 assay was used to evaluate the effect of these two herbs on the proliferation of cancer cells; AO/PI staining and JC-1 were used to detect Hep-1 cells apoptosis; the expression of Bax, Bcl-2, PARP, TRIB3, and XIAP genes was detected by real time quantitative PCR; the activity of caspase-3 and caspase-8 was determined with quantitative fluorescence method. The experimental results showed that compared with Tax, Res medication alone, joint group significantly enhanced inhibition of Hep-2 cells activity, decreased the dosage of Tax, increased the expression of Bax and PARP, TRIB3, reduced the expression of the Bcl-2 and XIAP, and promoted the activity of caspase-3 and caspase-8. The test results showed that compared with the single medication, combined group could significantly increase the inhibitory effect on Hep-2 cells, significantly reduce Tax dosage, increase expressions of Bax, PARP, TRIB3, reduce expressions of Bcl-2, XIAP, and promote activity of caspase-3, caspase-8. This indicated apoptosis of human laryngeal carcinoma cell strain Hep-2 may be induced with Res, Tax, and the combination of these two herbs by mitochondria pathway. It provides valuable clue for further research on combination of Res and Tax for the treatment of laryngeal cancer, and expanding the combined application of Res and Tax.
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PMID:[Apoptosis mechanism of taxol combined with resveratrol on human laryngeal carcinoma Hep-2 cells]. 2886 67

Aspernolide A, a butyrolactone secondary metabolite, was purified from the endophytic fungus Cladosporium cladosporioides derived from roots of Camptotheca acuminata Decne. In this study, the antitumor activity and mechanisms of aspernolide A on human laryngeal cancer Hep-2 and TU212 cells were studied by MTT (3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay, morphological observation and Western blotting. The results showed that aspernolide A significantly inhibited the proliferation of Hep-2 and TU212 cells in dose- and time-dependent manners. Morphological changes of apoptotic cells could be observed under an inverted microscope, such as irregular margins, decreased adherence ability and chromatin condensation. The expressions of Bax, Caspase-9, Caspase-3 and PARP (poly ADP-ribose polymerase) increased with the increase of dosage while Bcl-2 decreased, suggesting that the apoptotic mechanism might be related to the mitochondrial apoptotic pathway. Moreover, the expression of the phosphorylation of STAT3 decreased with the increase of dosage, suggesting that the apoptotic mechanism might be related to the STAT3 signaling pathway. All these conclusions indicated that aspernolide A has the potential anti-laryngocarcinoma effects.
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PMID:Aspernolide A Inhibits the Proliferation of Human Laryngeal Carcinoma Cells through the Mitochondrial Apoptotic and STAT3 Signaling Pathways. 3089 85

Andrographolide is a natural diterpenoid from Andrographis paniculata that has been proposed as an anticancer agent as well as a chemosensitizer for use in combination with anticancer drugs. Carboplatin is the first-line chemotherapeutic agent for advanced laryngeal carcinoma. However, the clinical efficacy of carboplatin is limited by drug resistance and side effects. The aim of this study was to investigate whether andrographolide has a synergistic antitumor effect with carboplatin on human laryngeal cancer cells. Hep-2 cells were exposed to andrographolide with or without carboplatin. The effects of indicated therapies were examined using the Cell Counting Kit-8 assay, the colony-forming assay, the Hoechst 33342/PI double staining, and flow cytometry analysis. The molecular mechanism was assessed by reactive oxygen species (ROS) detection and western blot. At the sublethal concentration, andrographolide increased carboplatin sensitivity of Hep-2 cells by increasing carboplatin-induced apoptosis and inhibiting cell viability. Moreover, we found that andrographolide sensitized carboplatin mainly through the induction of ROS generation and apoptotic signaling. Taken together, these results indicate that andrographolide, along with carboplatin, synergistically inhibited cell proliferation and induced mitochondrial apoptosis of Hep-2 cells by increasing the intracellular ROS, regulating the mitogen-activated protein kinase and phosphatidylinositol 3-kinase (PI3K/AKT) pathways, altering the BCL2/BAX ratio, and ultimately activating the cleavage of Caspase-3 and PARP. These results suggest that andrographolide sensitizes human laryngeal cancer cells to carboplatin-induced apoptosis by increasing ROS levels.
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PMID:Andrographolide sensitizes Hep-2 human laryngeal cancer cells to carboplatin-induced apoptosis by increasing reactive oxygen species levels. 3130 53