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:2.7.10.1 (ERK)
95,504 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Current agents for the treatment of non-small-cell lung cancer include gemcitabine (Gemzar), paclitaxel (Taxol), docetaxel (Taxotere), vinorelbine (Navelbine), and irinotecan (CPT-11, Camptosar). Experimental agents include pemetrexed (LY231514, Alimta) and tirapazamine. Molecular and biological therapies include angiogenesis inhibitors, epidermal growth factor receptor inhibitors, HER2/neu inhibitors, and inhibitors of ras activation and function. Doublet chemotherapy is currently the standard treatment for advanced non-small-cell lung cancer. In the past 2 years, randomized trials have shown that many of the new two-drug combinations used to treat non-small-cell lung cancer have equivalent efficacy. These combinations produce 1-year survival rates of about 35% and 2-year survival rates of about 15%. Toxicity rates vary but are sufficiently low as to make the development of three-drug combinations feasible. Preliminary studies from several phase I and II trials suggest that triplet therapy can improve survival beyond that of double therapy regimens.
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PMID:Triplet combination chemotherapy and targeted therapy regimens. 1130 45

Epidermal growth factor receptor [EGFR (HER1, erbB1)] is a receptor with associated tyrosine kinase activity, and is expressed in colorectal cancers and many other solid tumors. We examined the effect of the selective EGFR tyrosine kinase inhibitor (EGFR-TKI) gefitinib ("Iressa") in combination with the DNA topoisomerase I inhibitor CPT-11 (irinotecan) on human colorectal cancer cells. EGFR mRNA and protein expression were detected by RT-PCR and immunoblotting in all 7 colorectal cancer cell lines studied. Gefitinib inhibited the cell growth of the cancer cell lines in vitro with an IC(50) range of 1.2-160 microM by 3,(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay. Lovo cells exhibited the highest level of protein and autophosphorylation of EGFR and were the most sensitive to gefitinib. The combination of gefitinib and CPT-11 induced supra-additive inhibitory effects in COLO320DM, WiDR and Lovo cells, assessed by an in vitro MTT assay. Administration of gefitinib and CPT-11 had a supra-additive inhibitory effect on WiDR cells and tumor shrinkage was observed in Lovo cell xenografts established in nude mice, whereas no additive effect of combination therapy was observed in COLO320DM cells. To elucidate the mechanisms of synergistic effects, the effect of CPT-11-exposure on phosphorylation of EGFR was examined by immunoprecipitation. CPT-11 increased phosphorylation of EGFR in Lovo and WiDR cells in time- and dose-dependent manners. This EGFR activation was completely inhibited by 5 microM gefitinib and gefitinib-induced apoptosis was enhanced by combination with CPT-11, measured by PARP activation although no PARP activation was induced by 5 microM CPT-11 alone. These results suggested that these modification of EGFR by CPT-11, in Lovo cells, is a possible mechanism for the synergistic effect of CPT-11 and gefitinib. These findings imply that the EGFR-TKI gefitinib and CPT-11 will be effective against colorectal tumor cells that express high levels of EGFR, and support clinical evaluation of gefitinib in combination with CPT-11, in the treatment of colorectal cancers.
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PMID:Synergistic interaction between the EGFR tyrosine kinase inhibitor gefitinib ("Iressa") and the DNA topoisomerase I inhibitor CPT-11 (irinotecan) in human colorectal cancer cells. 1464 15

As a single agent the ERBB1 inhibitor, gefitinib (Iressa; ZD1839) showed minimal activity against a panel of 10 pediatric tumor xenografts that do not express the ERBB1 receptor. However, combined with irinotecan (CPT-11), significantly greater than additive activity was observed in four of eight models (P < 0.05), and the combination showed enhanced activity against three additional tumor lines. Breast cancer resistance protein (ABCG2), a transporter that confers resistance to SN-38 (the active metabolite of irinotecan), was readily detected in six of nine xenograft models examined by immunohistochemistry. In vitro gefitinib potently reversed resistance to SN-38 only in a cell line that overexpressed functional ABCG2. However, overexpression of ABCG2 did not decrease accumulation nor increase the rate of efflux of [(14)C]gefitinib. On the basis of these results and the distribution of Abcg2 in mouse tissues, we assessed the ability of gefitinib to modulate irinotecan pharmacokinetics. Oral gefitinib coadministration resulted in no change in clearance of intravenously administered irinotecan. However, gefitinib treatment dramatically increased the oral bioavailability of irinotecan after simultaneous oral administration. It is concluded that gefitinib may modulate SN-38 activity at the cellular level to reverse tumor resistance mediated by ABCG2 through inhibiting drug efflux and may be used potentially in humans to modulate the oral bioavailability of a poorly absorbed camptothecin such as irinotecan.
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PMID:Gefitinib enhances the antitumor activity and oral bioavailability of irinotecan in mice. 1549 75

EGFR mutations are a major determinant of lung tumor response to gefitinib, an EGFR-specific tyrosine kinase inhibitor. Obtaining a response from lung tumors expressing wild-type EGFR is a major obstacle. The combination of gefitinib and cytotoxic drugs is one strategy against lung cancers expressing wild-type EGFR. The DNA topoisomerase inhibitor irinotecan sulfate (CPT-11) is active against lung cancer. We examined the sensitivity of lung cancers expressing wild- or mutant-type EGFR to the combination of gefitinib and CPT-11. The in vitro effect of gefitinib and SN-38 (the active metabolite of CPT-11) was examined in seven lung cancer cell lines using the dye formation assay with a combination index. When administered concurrently, gefitinib and SN-38 had a synergistic effect in five of the seven cell lines expressing wild-type EGFR, whereas the combination was antagonistic in PC-9 cells and a PC-9 subline resistant to gefitinib and expressing deletional mutant EGFR (PC-9/ZD). When administered sequentially, treatment with SN-38 followed by gefitinib had remarkable synergistic effects in the PC-9 and PC-9/ZD cells. In an in vivo tumor-bearing model, this combination had a schedule-dependent synergistic effect in the PC-9 and PC-9/ZD cells. An immunohistochemical analysis of the tumors in mice treated with CPT-11 and gefitinib demonstrated that the number of Ki-67 positive tumor cells induced by CPT-11 treatment was decreased when CPT-11 was administered in combination with gefitinib. In conclusion, the sequential combination of CPT-11 and gefitinib is considered to be active against lung cancer.
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PMID:Effects of different combinations of gefitinib and irinotecan in lung cancer cell lines expressing wild or deletional EGFR. 1671 12

Molecular markers predicting the efficacy of CPT-11 based chemotherapies in patients with colorectal cancer (CRC) are unknown. Therefore, we investigated whether mRNA levels of drug targets (Topoisomerase I, TS), enzymes involved in 5-FU metabolism (DPD), in angiogenesis (EGFR, IL-8, VEGF) and in DNA-repair/drug detoxification (ERCC1, GST-P1) are associated with the clinical outcome of patients with CRC treated with first-line CPT-11 based chemotherapy. Thirty three patients with metastatic CRC were included in the study. Intratumoral gene expression levels were assessed from paraffin-embedded tissue samples, using laser capture microdissection and quantitative Real-Time PCR. Complete response was observed in 1 patient, partial response in 12 patients, stable disease in 13 patients and progressive disease in 6 patients. Response was inevaluable for 1 patient. Patients with complete response or partial response were classified as responders, while patients with stable disease or progressive disease were classified as nonresponders. High intratumoral mRNA levels of EGFR, ERCC1 and GSPT-P1 were each significantly associated with response to CPT-11 based chemotherapy. Recursive partitioning analysis showed that mRNA levels of EGFR and ERCC1 are primarily responsible for delineating responders from nonresponders. Also, the combination of high intratumoral gene expression levels of both EGFR and ERCC1 was significantly associated with progression-free survival. The mRNA levels of EGFR had a significant correlation with expression levels of ERCC1, GST-P1 and VEGF. This small retrospective study suggests that gene expression levels of EGFR, ERCC1 and GST-P1 may be useful in predicting the clinical outcome of patients with metastatic CRC treated with first-line CPT-11 based chemotherapy.
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PMID:Molecular determinants of irinotecan efficacy. 1689 65

Erlotinib (Tarceva, OSI-774) is a potent, orally available, small-molecule inhibitor of HER1/EGFR tyrosine-kinase activity. In this study, the antitumor activity of erlotinib was evaluated in two human colorectal tumor xenograft models (LoVo and HCT116) in athymic mice. When erlotinib was administered as monotherapy, significant tumor growth inhibition (TGI) was seen in the LoVo model at both 100 mg/kg [TGI > 100%, P < 0.001; 6/10 partial regressions (PRs)] and 25 mg/kg (TGI = 79%, P < 0.001) doses. However, the HCT116 xenograft model was not responsive to any dose of erlotinib tested. The differential response to erlotinib of these two tumor models was not a result of differences in HER1/EGFR expression levels since these were similar in both cell lines. However, it was demonstrated that resistance to erlotinib in the HCT116 model may be a result of persistent activation of ERK in these tumors. Based on the single agent activity of erlotinib in LoVo tumors, a combination study with CPT-11 (Camptosar, irinotecan) was performed. CPT-11 at the optimal dose of 60 mg/kg or a lower dose of 15 mg/kg resulted in significant TGI (TGI > 100%, P < 0.001, and TGI = 93%, P < 0.001, respectively) in LoVo-bearing mice. Combination treatment with erlotinib (25 mg/kg) and CPT-11 (15 mg/kg) produced significantly greater antitumor activity (TGI > 100%, P < 0.001; 10/10 PRs) than either agent alone (P < 0.05), with no increase in toxicity. These data indicate that erlotinib can enhance the antitumor activity of CPT-11, without enhanced toxicity, in the LoVo human colorectal tumor xenograft model.
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PMID:Antitumor activity of HER1/EGFR tyrosine kinase inhibitor erlotinib, alone and in combination with CPT-11 (irinotecan) in human colorectal cancer xenograft models. 1693 4

Resistance to chemotherapeutic agents is one of the distinct features of cancer cells. We evaluate the role of activated MEK-ERK signaling in Camptotecin/irinotecan (CPT-11)-induced cell death using constitutively activated MEK1-transfected normal rat intestinal epithelial cells (IEC-caMEK cells). A CPT-11-induced inhibitory concentration of 50% was determined by WST assay. Apoptosis was evaluated by DNA staining and fragmented DNA analysis. Protein expressions were analyzed by western blotting. We also examined the role of cyclooxygenase-2 in the cell systems. IEC-caMEK cells possessed survival advantages compared to control cells. Apoptosis was remarkably suppressed in IEC-caMEK cells. Western blot analysis revealed increased expression of Bcl-2, Bcl-xL, Mcl-1, and COX-2 and decreased expression of Bak in IEC-caMEK cells. The COX-2 selective inhibitor ameliorated the antiapoptotic nature of IEC-caMEK cells. MEK activation suppressed CPT-11-induced apoptosis in IEC-caMEK cells via a COX-2- dependent mechanism. Therefore, MEK-ERK signaling may contribute to the drug-resistant nature of cancer cells.
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PMID:MEK activation suppresses CPT11-induced apoptosis in rat intestinal epithelial cells through a COX-2-dependent mechanism. 1739 18

Taxanes (TX) were administered to 246 of 292 patients with recurrent/metastatic breast cancer (MBC) who were treated in Hiei Hospital between January 2001 and May 2006. Recently, TX has been increasingly prescribed for preoperative treatment and postoperative adjuvant therapy. To improve the prognosis of MBC, regimens effective for TX-resistant cancer patients should be developed. In this study, with respect to hormone receptor (HR) and Her 2/neu (HER 2), we retrospectively investigated whether our series responded to the regimens used after TX resistance was acquired. As post TX-resistance therapy (trastuzumab was combined in HER2-positive patients), 387 treatment regimens were administered to 166 patients. The following regimens achieved a response rate (patients achieving PR or CR/patients who could be evaluated) of 10% or more: combination therapy with TX and capecitabine (11/61, 18%), CPT-11 (10/57, 17.5%), vinorelbine (5/46, 10.9%), MFL-P (continuous treatment with MTX, 5-FU, LV, and CDDP) (12/47, 25.5%), and DMpC (5'-DFUR, MPA, CPA p.o.) (5/16, 31.2%). The latter 2 regimens achieved a high response rate,and some HR (-) and HER 2 (-) patients also responded to these regimens. In HR (+) or HER 2 (+) patients who responded to TX, survival was longer than that of non-responders. However, there was no difference in the treatment responsiveness of post-TX regimens between TX-responders and non-responders, suggesting the survival-prolonging effect of TX.
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PMID:[Evaluation of therapeutic regimens for taxane-resistant recurrent/metastatic breast cancer]. 1763 40

The purpose of our study was to determine whether the dual inhibition of epidermal growth factor receptor (EGFR) and vascular endothelial growth factor receptor (VEGFR) signaling pathways in tumor-associated endothelial cells can inhibit the progressive growth of human colon carcinoma in the cecum of nude mice. SW620CE2 human colon cancer cells growing in culture and orthotopically in the cecum of nude mice expressed a high level of transforming growth factor alpha (TGF-alpha) and vascular endothelial growth factor (VEGF) but were negative for EGFR, human epidermal growth factor receptor 2 (HER2), and VEGFR. Double immunofluorescence staining revealed that tumor-associated endothelial cells expressed EGFR, VEGFR2, phosphorylated EGFR (pEGFR), and phosphorylated VEGFR (pVEGFR). Treatment of mice with either 7H-pyrrolo [2,3-d]-pyrimidine lead scaffold (AEE788; an inhibitor of EGFR and VEGFR tyrosine kinase) or CPT-11 as single agents significantly inhibited the growth of cecal tumors (P < .01); this decrease was even more pronounced with AEE788 combined with CPT-11 (P < .001). AEE788 alone or combined with CPT-11 also inhibited the expression of pEGFR and pVEGFR on tumor-associated endothelial cells, significantly decreased vascularization and tumor cell proliferation, and increased the level of apoptosis in both tumor-associated endothelial cells and tumor cells. These data demonstrate that targeting EGFR and VEGFR signaling on tumor-associated endothelial cells provides a viable approach for the treatment of colon cancer.
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PMID:Inhibition of epidermal growth factor receptor and vascular endothelial growth factor receptor phosphorylation on tumor-associated endothelial cells leads to treatment of orthotopic human colon cancer in nude mice. 1808 14

Therapy for metastatic colorectal cancer has been improved in terms of response rate, time to progression and overall survival by the emergence of anti-EGFR monoclonal antibodies (cetuximab and panitumumab) in combination with standard cytotoxic chemotherapy (oxaliplatin or CPT-11-based combinations). However, the benefits of cetuximab and panitumumab are confined to KRAS wild-type (KRAS-wt) colorectal tumours; KRAS-mutated tumours rarely respond to these drugs. Of all colorectal tumours, 65% are KRAS-wt tumours, but anti-EGFR therapies are effective for only 60-70% of these. Therefore, other biomarkers and molecular pathways must be involved in the response to anti-EGFR therapies in KRASwt colorectal tumours. Factors that may explain the lack of response include EGFR ligands, EGFR phosphorylation levels, the number of EGFR copies, the status of the KRAS effector B-RAF and the alternative intracellular PIK3CA/ PTEN/AKT and JAK/STAT signalling pathways. A battery of biomarkers is needed to select the patients that will be most sensitive to anti-EGFR therapies. Such patterns may be a novel and cost-effective tool to develop tailored treatments. This manuscript will review biomarkers and molecular pathways that are involved in the tumour response to anti-EGFR therapies.
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PMID:Biomarkers and anti-EGFR therapies for KRAS wild-type metastatic colorectal cancer. 1991 37


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