Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: 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)

Focal adhesion kinase, FAK is a 125 kDa nonreceptor tyrosine kinase that localizes to focal adhesions. FAK is overexpressed in human tumors and regulates cellular adhesion and survival signaling. We have shown previously that the dominant-negative FAK, C-terminal FAK-CD, caused detachment and apoptosis in human breast cancer cells, and that overexpression of an activated form of Src tyrosine kinase or epidermal growth factor receptor, EGFR, suppressed FAK-CD induced apoptotic effects in breast cancer cells. In the present study, we studied the effect of a novel FAK inhibitor, TAE226 (Novartis, Inc.), on the breast cancer cell lines. We used stable breast cancer cell lines overexpressing Src (MCF-7-Src and BT474-Src) or overexpressing EGFR (BT474-EGFR), and control breast cancer cell lines for the treatment with different doses of TAE226 drug. The detachment and apoptosis caused by TAE226 was analyzed and compared with the effect of the dominant-negative adenoviral FAK-CD. The TAE226 drug caused a dose-dependent increase of detachment and apoptosis in both BT474 and MCF-7-Vector and Src cells and in BT474-EGFR and BT474-pcDNA3 cells. Additionally, TAE226 caused downregulation of Y397-FAK, FAK and activation of PARP or caspase-3 proteins. Both Src and EGFR-overexpressing cells were not resistant to the TAE226 treatment compared to FAK-CD treatment. In addition, normal breast MCF-10A cell line was resistant to both TAE226 drug and to the Ad-FAK-CD inhibitor. Thus, inhibition of autophosphorylation activity of FAK with the TAE226 inhibitor at 10-20 microM is effective in causing apoptosis in breast cancer cells, resistant to the Ad-FAK-CD inhibitor that can be used effectively in therapy.
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PMID:TAE226-induced apoptosis in breast cancer cells with overexpressed Src or EGFR. 1784 51

Oridonin, a diterpenoid isolated from the plant Rabdosia rubescens, induces human epidermoid carcinoma A431 cell death through apoptosis and tyrosine kinase pathway. To examine the pathway of oridonin-induced A431 cell death, morphologic observation, lactate dehydrogenase activity-based assay, DNA agarose gel electrophoresis and Western blot analysis were carried out. When A431 cells, which overexpress epidermal growth factor receptor (EGFR), were treated with oridonin, caspase-3 was activated followed by the degradation of caspase-3 substrates, inhibitor of caspase-activated DNase (ICAD) and poly(ADP-ribose) polymerase (PARP) in a time-dependent manner. Oridonin promoted the release of cytochrome c and the down-regulation of mitochondrial transmembrane potential (DeltaPsim). Oridonin up-regulated the expression ratio of mitochondrial proteins, Bax/Bcl-2. In addition, the total tyrosine kinase activity of A431 cellular proteins and the expression of EGFR were markedly reduced after oridonin treatment. Taken together, oridonin induced apoptosis in A431 cells via mitochondrial pathway, activation of caspase-3 and inhibition of tyrosine kinase activities.
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PMID:Oridonin induces human epidermoid carcinoma A431 cell apoptosis through tyrosine kinase and mitochondrial pathway. 1805 84

One of the mechanisms of the antitumor activity of green tea (-)-epigallocatechin-3-gallate (EGCG) is associated with its effect on epidermal growth factor receptor (EGFR)-mediated signaling transduction pathways. We investigated whether combining EGCG with the EGFR-tyrosine kinase inhibitor (EGFR-TKI) erlotinib may augment erlotinib-induced cell growth inhibition of squamous cell carcinoma of the head and neck (SCCHN) in a mouse xenograft model. In vitro studies with 5 head and neck cancer cell lines revealed that synergistic cell growth inhibition by the combination of EGCG and erlotinib was associated with significantly greater inhibition of pEGFR and pAKT, increased activation of caspases 9, 3 and PARP compared to the inhibition induced by EGCG or erlotinib alone. Erlotinib inhibited phosphorylation of EGFR, stabilizing EGFR at the plasma membrane, whereas EGCG induced EGFR internalization and ubiquitin-degradation, ultimately undermining EGFR signaling. The efficacy of the combination treatment was investigated with nude mice (n = 25) orally gavaged with vehicle control, EGCG, erlotinib or the combination at the same doses for 7 days, followed by subcutaneous injection with Tu212 cells. Animals were continuously administered the agents 5 days weekly for 7 weeks. The combined treatment resulted in significantly greater inhibition of tumor growth and delayed tumor progression as a result of increased apoptosis, decreased cell proliferation and reduced pEGFR and pAKT compared to the single agent treatment groups. Our results suggest a synergistic antitumor effect of a combined treatment with EGCG and erlotinib, and provide a promising regimen for future chemoprevention and treatment of SCCHN.
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PMID:Synergistic inhibition of head and neck tumor growth by green tea (-)-epigallocatechin-3-gallate and EGFR tyrosine kinase inhibitor. 1854 67

Inhibitors of the epidermal growth factor receptor (EGFR) have generated considerable hope for cancer treatment, specifically for lung and breast cancers. Therefore, identification of a natural, nontoxic agent(s) as an inhibitor of EGFR is of considerable importance. Delphinidin, an anthocyanidin present in pigmented fruits and vegetables, possesses potent antioxidant and antiproliferative properties. In our study, employing EGFR positive breast cancer AU-565 cells and immortalized MCF-10A cells, we evaluated the effect of delphinidin on EGFR and its downstream signaling pathways. Delphinidin (5-40 microM; 3 hr) treatment of both AU-565 cells and MCF-10A cells inhibited the (i) phosphorylation of EGFR, (ii) activation of PI3K, (iii) phosphorylation of AKT and MAPK. Further, delphinidin treatment of AU-565 cells inhibited EGF-induced autophosphorylation of EGFR, AKT and MAPK, activation of PI3K and cell invasion. We then compared the growth inhibitory effects of delphinidin (5-40 microM; 48 hr), and found that it resulted in a decrease in cell growth of AU-565 and MCF-10A cells but had only minimal effects on normal mammary epithelial 184A1 cells. Treatment of AU-565 cells with delphinidin resulted in (i) induction of apoptosis, (ii) cleavage of PARP protein, (iii) activation of caspase-3 and (iv) downregulation of Bcl-2 with an increase in the expression of Bax. In summary, our study identifies a naturally occurring dietary agent delphinidin as an effective inhibitor of EGFR signaling in breast cancer cells. We suggest that delphinidin could be developed as an agent for the management of EGFR positive human cancers.
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PMID:Inhibition of epidermal growth factor receptor signaling pathway by delphinidin, an anthocyanidin in pigmented fruits and vegetables. 1862 29

Triple-negative breast cancer is a subtype of breast cancer that is clinically negative for expression of estrogen and progesterone receptors (ER/PR) and HER2 protein. It is characterized by its unique molecular profile, aggressive behavior, distinct patterns of metastasis, and lack of targeted therapies. Although not synonymous, the majority of triple-negative breast cancers carry the "basal-like" molecular profile on gene expression arrays. The majority of BRCA1-associated breast cancers are triple-negative and basal-like; the extent to which the BRCA1 pathway contributes to the behavior of sporadic basal-like breast cancers is an area of active research. Epidemiologic studies illustrate a high prevalence of triple-negative breast cancers among younger women and those of African descent. Increasing evidence suggests that the risk factor profile differs between this subtype and the more common luminal subtypes. Although sensitive to chemotherapy, early relapse is common and a predilection for visceral metastasis, including brain metastasis, is seen. Targeted agents, including epidermal growth factor receptor (EGFR), vascular endothelial growth factor (VEGF), and poly (ADP-ribose) polymerase (PARP) inhibitors, are currently in clinical trials and hold promise in the treatment of this aggressive disease.
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PMID:Understanding and treating triple-negative breast cancer. 1898 22

Exposure to extensive ultraviolet (UV) rays is a major cause of skin cancer, which is thought to be initiated by DNA mutations. Members of the epidermal growth factor receptor (EGFR) family are important in various pathophysiologic processes like cancer and are shown to be phosphorylated upon UV exposure. Here we show that EGFR phosphorylation by modest UV doses is dependent on metalloprotease activity and resultant epidermal growth factor (EGF) family proligand shedding. This proligand cleavage releases the mature ligand, which then binds to and activates EGFR. We show that UV induced EGFR phosphorylation in transformed cell lines of melanocyte and keratinocyte origin, which was reduced upon preincubation with a broad-spectrum metalloprotease inhibitor, BB94. UV also activated EGFR downstream signaling via Erk and Akt pathways in a BB94-sensitive manner. Furthermore, using neutralizing antibodies we found that proligand amphiregulin was required for UV-induced EGFR activation in SCC-9 cells. Using RNAi this EGFR activation was further shown to depend on the metalloproteases ADAM9 and ADAM17 in SCC-9 cells. cDNA array hybridization and RT-PCR analysis showed overexpression of a Disintegrin and a Metalloproteases (ADAMs) and EGF family proligands in melanoma cell lines. Additionally, blocking EGFR signal transactivation by BB94 led to increased apoptosis in UV-irradiated cells. EGFR signal transactivation also led to increased stability of the DNA repair protein, PARP, under UV stress. Thus, both antiapoptotic and DNA repair pathways are activated simultaneously by EGFR signal transactivation. Together, our data provide novel insights into the mechanism of UV-induced EGFR activation, suggesting broad relevance of the UV-ADAM-proligand-EGFR-Erk/Akt pathway and its significance in skin cancer.
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PMID:UV-induced EGFR signal transactivation is dependent on proligand shedding by activated metalloproteases in skin cancer cell lines. 1900 95

Honokiol is a naturally occurring neolignan abundant in Magnoliae Cortex and has showed anti-proliferative and pro-apoptotic effects in a wide range of human cancer cells. However, the molecular mechanisms on the anti-proliferative activity in cancer cells have been poorly elucidated. In this study, we evaluated the growth inhibitory activity of honokiol in cultured estrogen receptor (ER)-negative MDA-MB-231 human breast cancer cells. Honokiol exerted anti-proliferative activity with the cell cycle arrest at the G0/G1 phase and sequential induction of apoptotic cell death in a concentration-dependent manner. The honokiol-induced cell cycle arrest was well correlated with the suppressive expression of CDK4, cyclin D1, CDK2, cyclin E, c-Myc, and phosphorylated retinoblastoma protein (pRb) at Ser780. Apoptosis caused by honokiol was also concomitant with the cleavage of caspases (caspase-3, -8, and -9) and Bid along with the suppressive expression of Bcl-2, but it was independent on the expression of Bax and p53. In addition, honokiol-treated cells exhibited the cleavage of poly (ADP-ribose) polymerase (PARP) and DNA fragmentation. In the analysis of signal transduction pathway, honokiol down-regulated the expression and phosphorylation of c-Src, epidermal growth factor receptor (EGFR), and Akt, and consequently led to the inactivation of mTOR and its downstream signal molecules including 4E-binding protein (4E-BP) and p70 S6 kinase. These findings suggest that honokiol-mediated inhibitory activity of cancer cell growth might be related with the cell cycle arrest and induction of apoptosis via modulating signal transduction pathways.
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PMID:Down-regulation of c-Src/EGFR-mediated signaling activation is involved in the honokiol-induced cell cycle arrest and apoptosis in MDA-MB-231 human breast cancer cells. 1913 78

We observed that treatment of prostate cancer cells for 24 h with magnolol, a phenolic component extracted from the root and stem bark of the oriental herb Magnolia officinalis, induced apoptotic cell death in a dose- and time-dependent manner. A sustained inhibition of the major survival signal, Akt, occurred in magnolol-treated cells. Treatment of PC-3 cells with an apoptosis-inducing concentration of magnolol (60 microM) resulted in a rapid decrease in the level of phosphorylated Akt leading to inhibition of its kinase activity. Magnolol treatment (60 microM) also caused a decrease in Ser((136)) phosphorylation of Bad (a proapoptotic protein), which is a downstream target of Akt. Protein interaction assay revealed that Bcl-xL, an anti-apoptotic protein, was associated with Bad during treatment with magnolol. We also observed that during treatment with magnolol, translocation of Bax to the mitochondrial membrane occurred and the translocation was accompanied by cytochrome c release, and cleavage of procaspase-8, -9, -3, and poly(ADP-ribose) polymerase (PARP). Similar results were observed in human colon cancer HCT116Bax(+/-) cell line, but not HCT116Bax(-/-) cell line. Interestingly, at similar concentrations (60 microM), magnolol treatment did not affect the viability of normal human prostate epithelial cell (PrEC) line. We also observed that apoptotic cell death by magnolol was associated with significant inhibition of pEGFR, pPI3K, and pAkt. These results suggest that one of the mechanisms of the apoptotic activity of magnolol involves its effect on epidermal growth factor receptor (EGFR)-mediated signaling transduction pathways.
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PMID:Magnolol induces apoptosis via inhibiting the EGFR/PI3K/Akt signaling pathway in human prostate cancer cells. 1922 60

Triple negative (TN) breast cancer is more frequent in women who are obese or have type II diabetes, as well as young women of color. These cancers do not express receptors for the steroid hormones estrogen or progesterone, or the type II receptor tyrosine kinase (RTK) Her-2 but do have upregulation of basal cytokeratins and the epidermal growth factor receptor (EGFR). These data suggest that aberrations of glucose and fatty acid metabolism, signaling through EGFR and genetic factors may promote the development of TN cancers. The anti-type II diabetes drug metformin has been associated with a decreased incidence of breast cancer, although the specific molecular subtypes that may be reduced by metformin have not been reported. Our data indicates that metformin has unique anti-TN breast cancer effects both in vitro and in vivo. It inhibits cell proliferation (with partial S phase arrest), colony formation and induces apoptosis via activation of the intrinsic and extrinsic signaling pathways only in TN breast cancer cell lines. At the molecular level, metformin increases P-AMPK, reduces P-EGFR, EGFR, P-MAPK, P-Src, cyclin D1 and cyclin E (but not cyclin A or B, p27 or p21), and induces PARP cleavage in a dose- and time-dependent manner. These data are in stark contrast to our previously published biological and molecular effects of metformin on luminal A and B, or Her-2 type breast cancer cells. Nude mice bearing tumor xenografts of the TN line MDA-MB-231, treated with metformin, show significant reductions in tumor growth (p = 0.0066) and cell proliferation (p = 0.0021) as compared to untreated controls. Metformin pre-treatment, before injection of MDA-MB-231 cells, results in a significant decrease in tumor outgrowth and incidence. Given the unique anti-cancer activity of metformin against TN disease, both in vitro and in vivo, it should be explored as a therapeutic agent against this aggressive form of breast cancer.
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PMID:Metformin induces unique biological and molecular responses in triple negative breast cancer cells. 1971 81

Breast cancer is a heterogeneous disease characterised by a dysregulation of multiple pathways related to cell differentiation, cell cycle control, apoptosis, angiogenesis and development of metastasis. Acting against these pathways provides therapeutic targets for new targeted biologic therapies, which, in the future, might constitute a key for fighting cancer. The development of molecular technology in recent years has allowed a further comprehension of these mutations and dysregulated pathways leading to oncogenesis. New targeted biologic therapies will block essential functions of cancer cells and tumour stroma. A growing number of therapy options, alone or in combination with background treatments (chemotherapy, hormone therapy, radiotherapy), will allow oncologists a better adaptation of treatment to patients and disease characteristics. Examples of approved targeted agents in breast cancer include agents targeting the human epidermal growth factor receptor 2 (HER2), such as trastuzumab, lapatinib and the anti-VEGF bevacizumab. In addition, there are other therapy classes under evaluation, including novel antiEGFR or antiHER2 therapies; agents fighting other tyrosine kinases, including the Src and the insulinlike growth factor receptor; agents interfering critically relevant pathways, such as PI3K/AKT/mTOR inhibitors; and agents promoting apoptosis, such as PARP inhibitors (for particular breast cancer subtypes, such as basal-like, or breast cancer with BRCA mutations) and others. The better selectivity against malignant cells of these therapies, when compared to conventional chemotherapy, gives, a priori, at least two advantages to biologic treatments: fewer side effects and a more individualised treatment of cancer depending on the tumour's molecular characteristics. The ability to identify patients' subgroups and response predicting factors will be crucial in obtaining the greatest benefit with minimal toxicity levels. Unsolved questions remain, such as appropriate patient selection based on the expression of the therapeutic target in the tumour, the study of the efficacy of the drug in not so extensively pretreated populations and with a greater chance of response, the use of new pharmacodynamic models to help to define new response predicting factors for a specific new biologic therapy, the combined and rational use of different biologic therapies having different molecular targets and fighting the same target through a complementary mechanism of action that might improve clinical efficacy.
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PMID:Targeted therapy of metastatic breast cancer. 1982 6


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