ABSTRACT
BACKGROUND: The aim of the RECCORD registry was to gather real-world UK data on the use of targeted therapies in renal cell carcinoma (RCC) and assess clinical outcomes. Here, demographic and outcome data are presented with the treatment patterns and demographic profile of patients on the registry. PATIENTS AND METHODS: Patients were retrospectively identified at seven UK hospitals with large cancer centres in England (5), Scotland (1) and Wales (1). Anonymised data were collected through an online registry covering demographics, treatments and outcomes. Five hundred and fourteen UK adult patients with metastatic RCC were included in the study for analysis. Patients were included if they were treated for metastatic RCC at one of the seven centres, and started systemic anti-cancer treatment from March 2009 to November 2012 inclusive. In addition to demographic factors, the principal outcome measures were overall survival (OS), time to disease progression and toxicity. RESULTS: The majority of first-line treatment was with sunitinib; first-line use of pazopanib increased as the study progressed. 15.8% of patients received second-line treatment, half of whom were prescribed everolimus. Median OS (from initiation of first-line treatment) was 23.9 months (95% confidence interval [CI] 18.6-29.1 months), similar to that reported for clinical trials of targeted RCC therapies [Ljungberg B, Campbell SC, Choi HY et al. The epidemiology of renal cell carcinoma. Eur Urol 2011; 60: 615-621; Abe H, Kamai T. Recent advances in the treatment of metastatic renal cell carcinoma. Int J Urol 2013; 20: 944-955; Motzer RJ, Hutson TE, Tomczak P et al. Overall survival and updated results for sunitinib compared with interferon alfa in patients with metastatic renal cell carcinoma. J Clin Oncol 2009; 27: 3584-3590]. OS was significantly longer for those who received second-line treatment after disease progression (33.0 months; 95% CI 30.8-35.2 months) than those who did not (20.9 months; 95% CI 16.4-25.3 months; P = 0.008). CONCLUSIONS: RECCORD is a large 'real-world' database assessing metastatic RCC treatment patterns and outcomes. Treatment patterns changed over time as targeted therapies were approved and became widely available; survival data in RECCORD are consistent with those reported for systemic treatments in clinical trials. Kaplan-Meier analysis of results demonstrated that receiving second-line therapy was a major prognostic factor for longer OS.
Subject(s)
Angiogenesis Inhibitors/therapeutic use , Carcinoma, Renal Cell/drug therapy , Indoles/therapeutic use , Interferon-alpha/therapeutic use , Kidney Neoplasms/drug therapy , Pyrimidines/therapeutic use , Pyrroles/therapeutic use , Sulfonamides/therapeutic use , Aged , Carcinoma, Renal Cell/mortality , Carcinoma, Renal Cell/secondary , Disease Progression , Female , Humans , Indazoles , Kaplan-Meier Estimate , Kidney Neoplasms/mortality , Kidney Neoplasms/pathology , Male , Middle Aged , Registries , Retrospective Studies , Sunitinib , Treatment Outcome , United KingdomABSTRACT
INTRODUCTION: Preliminary studies show that device assisted intravesical therapies appear more effective than passive diffusion intravesical therapy for the treatment of non-muscle invasive bladder cancer (NMIBC) in specific settings, and phase III studies are now being conducted. Consequently, we have undertaken a non-systematic review with the objective of describing the scientific basis and mechanisms of action of electromotive drug administration (EMDA) and chemohyperthermia (CHT). METHODS: PubMed, ClinicalTrials.gov and the Cochrane Library were searched to source evidence for this non-systematic review. Randomised controlled trials, systematic reviews and meta-analyses were evaluated. Publications regarding the scientific basis and mechanisms of action of EMDA and CHT were identified, as well as clinical studies to date. RESULTS: EMDA takes advantage of three phenomena: iontophoresis, electro-osmosis and electroporation. It has been found to reduce recurrence rates in NMIBC patients and has been proposed as an addition or alternative to bacillus Calmette-Guérin (BCG) therapy in the treatment of high risk NMIBC. CHT improves the efficacy of mitomycin C by three mechanisms: tumour cell cytotoxicity, altered tumour blood flow and localised immune responses. Fewer studies have been conducted with CHT than with EMDA but they have demonstrated utility for increasing disease-free survival, especially in patients who have previously failed BCG therapy. CONCLUSIONS: It is anticipated that EMDA and CHT will play important roles in the management of NMIBC in the future. Techniques of delivery should be standardised, and there is a need for more randomised controlled trials to evaluate the benefits of the treatments alongside quality of life and cost-effectiveness.
Subject(s)
Antineoplastic Agents/administration & dosage , Electrochemotherapy/methods , Hyperthermia, Induced/methods , Urinary Bladder Neoplasms/therapy , Administration, Intravesical , Antineoplastic Agents/therapeutic use , Combined Modality Therapy , Humans , Neoplasm Invasiveness , Urinary Bladder Neoplasms/drug therapy , Urinary Bladder Neoplasms/pathologyABSTRACT
BACKGROUND: In the AXIS trial, axitinib prolonged progression-free survival (PFS) vs sorafenib in patients with advanced renal cell carcinoma (RCC) previously treated with sunitinib or cytokines. METHODS: In post hoc analyses, patients were grouped by objective response to prior therapy (yes vs no), prior therapy duration (< vs ⩾median), and tumour burden (baseline sum of the longest diameter < vs ⩾median). PFS and overall survival (OS), and safety by type and duration of prior therapy were evaluated. RESULTS: Response to prior therapy did not influence outcome with second-line axitinib or sorafenib. PFS was significantly longer in axitinib-treated patients who received longer prior cytokine treatment and sorafenib-treated patients with smaller tumour burden following sunitinib. Overall survival with the second-line therapy was longer in patients who received longer duration of prior therapy, although not significant in the sunitinib-to-axitinib sequence subgroup; OS was also longer in patients with smaller tumour burden, but not significant in the cytokine-to-axitinib sequence subgroup. Safety profiles differed modestly by type and duration of prior therapy. CONCLUSIONS: AXIS data suggest that longer duration of the first-line therapy generally yields better outcome with the second-line therapy and that lack of response to first-line therapy does not preclude positive clinical outcomes with a second-line vascular endothelial growth factor-targeted agent in patients with advanced RCC.
Subject(s)
Carcinoma, Renal Cell/drug therapy , Imidazoles/therapeutic use , Indazoles/therapeutic use , Kidney Neoplasms/drug therapy , Niacinamide/analogs & derivatives , Phenylurea Compounds/therapeutic use , Protein Kinase Inhibitors/therapeutic use , Antineoplastic Agents/adverse effects , Antineoplastic Agents/therapeutic use , Axitinib , Carcinoma, Renal Cell/mortality , Carcinoma, Renal Cell/pathology , Cytokines/therapeutic use , Disease-Free Survival , Humans , Imidazoles/adverse effects , Indazoles/adverse effects , Indoles/therapeutic use , Kidney Neoplasms/mortality , Kidney Neoplasms/pathology , Niacinamide/adverse effects , Niacinamide/therapeutic use , Phenylurea Compounds/adverse effects , Protein Kinase Inhibitors/adverse effects , Pyrroles/therapeutic use , Sorafenib , Sunitinib , Treatment Outcome , Tumor BurdenABSTRACT
AIMS: To determine whether primary care trusts' agreement or refusal to fund sorafenib or sunitinib affects outcomes for patients with metastatic renal cell carcinoma. MATERIALS AND METHODS: This retrospective audit was conducted in a tertiary referral centre for urological cancer. Requests to prescribe drugs not approved by the National Institute for Health and Clinical Excellence are recorded on a trust database. We obtained details of all requests made for sunitinib and sorafenib for patients with renal cell carcinoma since licence in 2006. Outcome measures analysed were overall survival measured from the date of request for funding and hospital resource use as measured from Payment by Results data. Known prognostic factors and the patient's Index of Multiple Deprivation score were assessed at baseline as potential confounders of survival difference. RESULTS: Seventy-nine patients were identified. The groups were similar with respect to prognostic factors and Index of Multiple Deprivation scores. Thirty-seven and eight patients had funding approved for sunitinib and sorafenib, respectively; 21 and 13 were turned down. Seven patients who were denied funding received one or other of these drugs by self-funding treatment. Survival was longer for patients who received treatment with a drug for which they had applied for funding than for those who did not (hazards ratio 0.46; 95% confidence interval 0.21-1.01; chi(2)=3.80; 1 d.f.; P=0.05); the advantage was similar for patients receiving sunitinib (hazards ratio=0.49; 95% confidence interval 0.18-1.36; chi(2)=1.86; 1 d.f.; P=0.17) and sorafenib (hazard ratio=0.44; 95% confidence interval 0.11-1.69; chi(2)=1.58; 1 d.f.; P=0.21). Overall National Health Service resource use apart from funding for the renal cancer drugs was similar for both groups. CONCLUSIONS: Compared with patients receiving treatment, patients denied access to sunitinib and sorafenib had substantially worse survival outcomes, despite receiving treatment from the same clinical team. Access to the new drugs did not have an effect on overall use of National Health Service resources by funded patients. Modern treatments for advanced renal cancer should be available to all National Health Service patients with the disease.
Subject(s)
Angiogenesis Inhibitors/therapeutic use , Carcinoma, Renal Cell/drug therapy , Carcinoma, Renal Cell/pathology , Kidney Neoplasms/drug therapy , Kidney Neoplasms/pathology , Protein Kinase Inhibitors/therapeutic use , Benzenesulfonates/pharmacology , Carcinoma, Renal Cell/mortality , Female , Humans , Indoles/pharmacology , Kidney/pathology , Kidney Neoplasms/mortality , Male , Medical Audit , Neoplasm Metastasis , Niacinamide/analogs & derivatives , Phenylurea Compounds , Pyridines/pharmacology , Pyrroles/pharmacology , Sorafenib , Sunitinib , Survival Analysis , United KingdomSubject(s)
Antineoplastic Agents/therapeutic use , Carcinoma, Renal Cell/drug therapy , Kidney Neoplasms/drug therapy , Lung Neoplasms/drug therapy , Lung Neoplasms/secondary , Sirolimus/analogs & derivatives , Humans , Liver Neoplasms/drug therapy , Liver Neoplasms/secondary , Male , Middle Aged , Protein Kinase Inhibitors/therapeutic use , Sirolimus/therapeutic useABSTRACT
Subjects affected by hereditary non-polyposis colorectal cancer exhibit a high susceptibility to colon and extracolonic tumours, due to MMR gene defects. Revised Bethesda criteria are used to select patients as candidates for genetic tests. Recently, the CRCAPRO model has been developed, based on family history of colorectal and endometrial cancers. Our study aims to evaluate the reliability of CRCAPRO in identifying mutation carriers. We used the CRCAPRO program to evaluate carrier probability risk in 99 patients fulfilling Amsterdam or Bethesda guidelines. MLH1 and MSH2 were studied by direct sequencing in all the 99 patients, and the study of microsatellite instability and of MMR proteins expression was performed. Nine MLH1 and nine MSH2 germline mutations were identified. Five out of the nine patients with MLH1 mutation showed a CRCAPRO risk evaluation of less than 20%. The same happened for four out of nine patients with MSH2 mutation. Of the 17 patients with an estimated risk of more than 80%, only four harboured a mutation, all in the MSH2 gene. The highest risk calculated by the CRCAPRO system in the nine carriers of a MLH1 mutation has been 31.7%. In our experience, the CRCAPRO program sensitivity and specificity appears to be low but needs to be further evaluated in larger samples.
Subject(s)
Colorectal Neoplasms, Hereditary Nonpolyposis/genetics , Software , Adaptor Proteins, Signal Transducing , Adult , Aged , Carrier Proteins/genetics , Carrier Proteins/metabolism , Colorectal Neoplasms, Hereditary Nonpolyposis/diagnosis , Colorectal Neoplasms, Hereditary Nonpolyposis/metabolism , DNA Mismatch Repair , DNA Mutational Analysis , Diagnosis, Computer-Assisted , Female , Genetic Testing/statistics & numerical data , Humans , Male , Microsatellite Instability , Middle Aged , MutL Protein Homolog 1 , MutS Homolog 2 Protein/genetics , MutS Homolog 2 Protein/metabolism , Nuclear Proteins/genetics , Nuclear Proteins/metabolismABSTRACT
Hereditary nonpolyposis colorectal cancer (HNPCC) is an inherited syndrome of cancer susceptibility caused by germ line mutations of genes participating in mismatch repair (MMR). Carriers of MMR gene mutations have an increased risk of colorectal cancers and cancer of other organs. Tumors of the endometrium represent the most frequent extracolonic malignancies in HNPCC. It has been suggested that women harboring MMR gene mutations have a higher risk of endometrial cancer than of colon cancer. Here, we describe an HNPCC patient with early-onset endometrial cancer and a strong familial history of endometrial tumors who harbored a germ line MSH2 splice site mutation (IVS9_2A>G). This mutation was responsible for abnormal messenger RNA processing, leading to the introduction of a premature stop signal and to the expression of a truncated MSH2 protein. In addition, the same mutation was associated with loss of MSH2 protein expression, high microsatellite instability, and PTEN inactivation. Although a direct relationship between the endometrial cancer susceptibility and the MSH2 mutation we found cannot be established, our observations, consistent with the work of other authors, suggest the involvement of germ line MSH2 abnormalities in endometrial tumor development and support the case for endometrial cancer screening in women from HNPCC families.
Subject(s)
Adenocarcinoma/genetics , Endometrial Neoplasms/genetics , MutS Homolog 2 Protein/genetics , Point Mutation , RNA Splice Sites/genetics , Adenocarcinoma/complications , Adenocarcinoma/metabolism , Adult , Base Sequence , Colorectal Neoplasms, Hereditary Nonpolyposis/complications , Colorectal Neoplasms, Hereditary Nonpolyposis/genetics , DNA Mutational Analysis/methods , Endometrial Neoplasms/complications , Endometrial Neoplasms/metabolism , Female , Genomic Instability , Humans , Immunohistochemistry , Molecular Sequence Data , MutS Homolog 2 Protein/metabolism , Pedigree , RNA Processing, Post-TranscriptionalABSTRACT
The molecular mechanisms involved in the development of oral squamous cell carcinomas (OSCC) are not yet well understood. Evidence of recent studies suggests that aberrant beta-catenin signalling may participate in the neoplastic transformation and that it is implicated in the development of several tumours. Beta-catenin is a component of the catenin family and plays a crucial role in cadherin mediated cell adhesion. However, it has recently been shown that beta-catenin is also involved in other functions such as intracellular signalling and the regulation of gene transcription. The aim of this study is to evaluate the presence of mutation in exon 3 of the beta-catenin gene in 20 OSCC cell lines. DNA was extracted using Qiagen Qiamp DNA minikit and a region encompassing the exon 3 of beta-catenin gene was amplified using a single PCR assay. The PCR products were analysed by SSCP and direct sequencing to detect any mutation of the gene. Most of the cell lines examined showed, by immunofluorescence, a beta-catenin delocalization. SSCP and sequence analysis of the PCR products did not show any mutation of the beta-catenin gene in any of the cell lines. In conclusion, although aberrant expressions or abnormal localization of beta-catenin have been detected in several OSCC cells, it appears that this finding has no relationship with beta-catenin gene mutations.
Subject(s)
Carcinoma, Squamous Cell/genetics , Mouth Neoplasms/genetics , Mutation , beta Catenin/genetics , Cell Line, Tumor , Exons , HumansABSTRACT
OBJECTIVES: The incidence of non-small cell lung cancer (NSCLC) is increasing among the elderly. We studied the toxicity and efficacy of a weekly schedule of gemcitabine and cisplatin in elderly patients with advanced NSCLC. METHODS: Patients aged 70 years or above with advanced NSCLC were treated in a phase II prospective trial with gemcitabine 1,000 mg/m(2) and cisplatin 35 mg/m(2) on days 1, 8 and 15 every 28 days. RESULTS: Forty-eight patients with a median age of 74 years (range 70-78) participated in the study. We observed 14 cases with partial response, 14 with stable disease and 16 with progressive disease, whilst 4 patients were not evaluable. By intention-to-treat analysis, partial response rate was 31.8% whilst progressive disease was 33.3%. Median survival was 9 months; 1-year survival probability was 34.4% and median time to progression was 4 months. Grade III-IV leukopenia was observed in 5/48 patients (10.4%), 20/48 patients (41.7%) had grade III-IV thrombocytopenia and 7/48 patients (14.6%) had grade III-IV anemia. One patient experienced grade III emesis and 2 patients had grade III-IV fatigue. CONCLUSIONS: At this dose and schedule the combination of gemcitabine and cisplatin appears to be an active and well-tolerated regimen for elderly patients with advanced NSCLC.
Subject(s)
Antineoplastic Combined Chemotherapy Protocols/therapeutic use , Carcinoma, Non-Small-Cell Lung/drug therapy , Deoxycytidine/analogs & derivatives , Lung Neoplasms/drug therapy , Adenocarcinoma/drug therapy , Adenocarcinoma/pathology , Aged , Antineoplastic Combined Chemotherapy Protocols/adverse effects , Carcinoma, Non-Small-Cell Lung/pathology , Carcinoma, Squamous Cell/drug therapy , Carcinoma, Squamous Cell/pathology , Cisplatin/administration & dosage , Deoxycytidine/administration & dosage , Dose-Response Relationship, Drug , Female , Humans , Lung Neoplasms/pathology , Male , Maximum Tolerated Dose , Neoplasm Staging , Prognosis , Prospective Studies , Treatment Outcome , GemcitabineABSTRACT
Pre-clinical data suggest a relationship between DNA MisMatch Repair (MMR) system failure, particularly the inactivation of genes hMLH1 and hMSH2, and resistance to drugs like cisplatin and carboplatin. We studied the correlation between loss of hMLH1 expression in tumour cells and clinical outcome in 38 patients with ovarian cancer, who underwent cisplatin-based chemotherapy. 19 patients (56%) showed loss of hMLH1 expression (Group A) while 15 patients (44%) showed normal hMLH1 expression (Group B). 4 patients were not evaluable for hMLH1 expression. The 2 groups of patients were similar for clinical characteristics, response to chemotherapy and time to progression. Group A patients showed a median survival of 55 months whereas Group B patients had a median survival of 12 months (P=0.014). Loss of hMLH1 expression was the only independent predictor of survival in the multivariate analysis. Our observations suggest a relationship between loss of hMLH1 and improved survival in advanced ovarian cancer.
Subject(s)
Neoplasm Proteins/genetics , Ovarian Neoplasms/genetics , Adaptor Proteins, Signal Transducing , Adult , Aged , Antineoplastic Agents/therapeutic use , Carrier Proteins , Cisplatin/therapeutic use , Disease Progression , Drug Resistance, Neoplasm , Female , Gene Expression Regulation, Neoplastic , Humans , Middle Aged , MutL Protein Homolog 1 , Nuclear Proteins , Ovarian Neoplasms/drug therapy , Regression Analysis , Survival AnalysisABSTRACT
BACKGROUND: The combination of gemcitabine and cisplatin has proven effective in the treatment of advanced non-small-cell lung cancer (NSCLC). However, the optimal schedule for administration of the two drugs has not yet been determined. In this study we evaluated the activity and toxicity of a weekly gemcitabine and cisplatin schedule. PATIENTS AND METHODS: Thirty-six untreated patients with stage IIIB IV NSCLC entered the study. Treatment consisted of gemcitabine 1000 mg/m2 i.v. and cisplatin 35 mg/m2 i.v., both given weekly on day 1,8, and 15, followed by one week of rest. RESULTS: Ninety-seven courses (273 weekly administrations) were delivered. The median dose-intensity was 612 mg/m2 per week for gemcitabine (82%) and 21 mg/m2 per week for cisplatin (80%). All 36 of the patients were evaluable for toxicity, and 30 for response. Partial remissions were observed in 12 patients, for an overall response rate of 40% (95% confidence interval (95% CI): 22.5%-57.5%). Most of the partial remissions were seen in IIIB patients (54% of the stage IIIB and 22% of the stage IV patients responded). According to the intent-to-treat principle, the response rate was 33.3% (12 of 36 patients). The median response duration was 9.9 months (range 4-23) and the median survival time 11.8 months (range 1-24). World Health Organization (WHO) grade 3-4 myelotoxicity was: thrombocytopenia in nine patients (25%), neutropenia in six (16.6%) and anemia in six (16.6%); there was very little additional major toxicity. CONCLUSIONS: This regimen appears to be active and to have a favourable toxicity profile.
Subject(s)
Antineoplastic Combined Chemotherapy Protocols/therapeutic use , Carcinoma, Non-Small-Cell Lung/drug therapy , Cisplatin/administration & dosage , Deoxycytidine/analogs & derivatives , Lung Neoplasms/drug therapy , Adult , Aged , Carcinoma, Non-Small-Cell Lung/mortality , Cisplatin/adverse effects , Deoxycytidine/administration & dosage , Deoxycytidine/adverse effects , Female , Humans , Lung Neoplasms/mortality , Male , Middle Aged , GemcitabineABSTRACT
The mutation cluster region in the APC gene defines a region of approximately 660 bp, in which the vast majority of its somatic mutations are found. These mutations disrupt the polypeptide chain, typically eliminating five of the seven repeated sequences of 20 amino acids (aa) each in the central region of the APC protein. To examine the relationship between loss of this structure and loss of function, we constructed APC deletion mutants that progressively truncated the protein across the mutation cluster region. The mutants were tested for their association with beta-catenin and their ability to down-regulate it in SW480 cells. The binding of beta-catenin to APC fragments required the inclusion of only a single 20-aa repeat sequence, whereas down-regulation required the presence of at least three of these repeat sequences, and those including the second repeat exhibited the highest activity. The mutation of three conserved serine residues in the second repeat greatly reduced the activity of an otherwise highly active APC fragment. Thus, the repeated 20-aa sequence is directly implicated in beta-catenin turnover. The elimination of at least five of these seven repeats due to somatic mutations suggests that loss of beta-catenin regulation by APC is selected for during tumor progression.
Subject(s)
Cytoskeletal Proteins/biosynthesis , Cytoskeletal Proteins/metabolism , Gene Expression Regulation, Neoplastic , Genes, APC , Mutation , Trans-Activators , Adenomatous Polyposis Coli Protein , Amino Acid Sequence , Amino Acid Substitution , Cadherins/biosynthesis , Cloning, Molecular , Colorectal Neoplasms , Cytoskeletal Proteins/chemistry , Humans , Molecular Sequence Data , Mutagenesis, Site-Directed , Peptide Fragments/pharmacology , Recombinant Proteins/biosynthesis , Recombinant Proteins/chemistry , Recombinant Proteins/metabolism , Repetitive Sequences, Nucleic Acid , Serine , Transfection , Tumor Cells, Cultured , beta CateninABSTRACT
Signal transduction by beta-catenin involves its posttranslational stabilization and downstream coupling to the Lef and Tcf transcription factors. Abnormally high amounts of beta-catenin were detected in 7 of 26 human melanoma cell lines. Unusual messenger RNA splicing and missense mutations in the beta-catenin gene (CTNNB1) that result in stabilization of the protein were identified in six of the lines, and the adenomatous polyposis coli tumor suppressor protein (APC) was altered or missing in two others. In the APC-deficient cells, ectopic expression of wild-type APC eliminated the excess beta-catenin. Cells with stabilized beta-catenin contained a constitutive beta-catenin-Lef-1 complex. Thus, genetic defects that result in up-regulation of beta-catenin may play a role in melanoma progression.
Subject(s)
Cytoskeletal Proteins/genetics , Gene Expression Regulation, Neoplastic , Genes, APC , Melanoma/genetics , Trans-Activators , Adenomatous Polyposis Coli Protein , Animals , Cell Line , Cytoskeletal Proteins/chemistry , Cytoskeletal Proteins/metabolism , DNA-Binding Proteins/metabolism , Humans , Lymphoid Enhancer-Binding Factor 1 , Melanoma/metabolism , Mice , Mutation , Point Mutation , RNA Splicing , RNA, Messenger/genetics , RNA, Neoplasm/genetics , Transcription Factors/metabolism , Transfection , Tumor Cells, Cultured , Up-Regulation , beta CateninABSTRACT
Signal transduction by beta-catenin involves its posttranslational stabilization and import to the nucleus where it interacts with transcription factors. Recent implications for beta-catenin signaling in cancer prompted us to examine colon cancer cell lines for the expression of LEF-1, a transcription factor that binds to beta-catenin. The analysis of several cell lines revealed the expression of LEF1 mRNA and a constitutive association of the LEF-1 protein with beta-catenin. In contrast to the colon cells, PC12 and 293 cells did not contain a beta-catenin-LEF-1 complex, even though both proteins were detected in cell lysates. In these cells, the association of endogenous LEF1 and beta-catenin was induced by stimulation with the wnt-1 proto-oncogene. The complex formed following transient stimulation with wnt-1 and also persisted in cells stably expressing wnt-1. Ectopic overexpression of beta-catenin in 293 cells also induced the assembly of the beta-catenin-LEF-1 complex and activated gene transcription from a LEF-1-dependent promotor. Expression of mutant oncogenic forms of beta-catenin identified in cancer cells resulted in higher levels of transcriptional activity. The results suggest that a cancer pathway driven by wnt-1, or mutant forms of beta-catenin, may involve the formation of a persistent transcriptionally active complex of beta-catenin and LEF1.
Subject(s)
Cell Transformation, Neoplastic/genetics , Cytoskeletal Proteins/biosynthesis , DNA-Binding Proteins/biosynthesis , Mutation , Proto-Oncogene Proteins/physiology , Trans-Activators , Transcription Factors/biosynthesis , Zebrafish Proteins , Animals , Cadherins/genetics , Cadherins/physiology , Cell Transformation, Neoplastic/metabolism , Colonic Neoplasms , Cytoskeletal Proteins/analysis , Cytoskeletal Proteins/genetics , DNA-Binding Proteins/analysis , DNA-Binding Proteins/genetics , Humans , Immunoblotting , Lymphoid Enhancer-Binding Factor 1 , Melanoma , Mice , PC12 Cells , Precipitin Tests , Proto-Oncogene Mas , Rats , Signal Transduction/genetics , Transcription Factors/analysis , Transcription Factors/genetics , Tumor Cells, Cultured , Wnt Proteins , Wnt1 Protein , beta CateninABSTRACT
The adenomatous polyposis coli gene (APC) is mutated in most colon cancers. The APC protein binds to the cellular adhesion molecule beta-catenin, which is a mammalian homolog of ARMADILLO, a component of the WINGLESS signaling pathway in Drosophila development. Here it is shown that when beta-catenin is present in excess, APC binds to another component of the WINGLESS pathway, glycogen synthase kinase 3beta (GSK3beta), a mammalian homolog of Drosophila ZESTE WHITE 3. APC was a good substrate for GSK3 beta in vitro, and the phosphorylation sites were mapped to the central region of APC. Binding of beta-catenin to this region was dependent on phosphorylation by GSK3 beta.
Subject(s)
Calcium-Calmodulin-Dependent Protein Kinases/metabolism , Cytoskeletal Proteins/metabolism , Trans-Activators , Adenomatous Polyposis Coli Protein , Animals , Cell Line , Glycogen Synthase Kinase 3 , Glycogen Synthase Kinases , Humans , Mice , Mutation , Phosphorylation , Protein Binding , Tumor Cells, Cultured , beta CateninABSTRACT
In response to stimulation with epidermal growth factor (EGF), the guanine nucleotide exchange factor human SOS1 (hSOS1) promotes the activation of Ras by forming a complex with Grb2 and the human EGF receptor (hEGFR). hSOS1 was phosphorylated in cells stimulated with EGF or phorbol 12-myristate 13-acetate or following co-transfection with activated Ras or Raf. Co-transfection with dominant negative Ras resulted in a decrease of EGF-induced hSOS1 phosphorylation. The mitogen-activated protein kinase (MAPK) phosphorylated hSOS1 in vitro within the carboxyl-terminal proline-rich domain. The same region of hSOS1 was phosphorylated in vivo, in cells stimulated with EGF. Tryptic phosphopeptide mapping showed that MAPK phosphorylated hSOS1 in vitro on sites which were also phosphorylated in vivo. Phosphorylation by MAPK did not affect hSOS1 binding to Grb2 in vitro. However, reconstitution of the hSOS1-Grb2-hEGFR complex showed that phosphorylation by MAPK markedly reduced the ability of hSOS1 to associate with the hEGFR through Grb2. Similarly, phosphorylated hSOS1 was unable to form a complex with Shc through Grb2. Thus phosphorylation of hSOS1, by affecting its interaction with the hEGFR or Shc, down-regulates signal transduction from the hEGFR to the Ras pathway.
Subject(s)
Adaptor Proteins, Signal Transducing , Epidermal Growth Factor/pharmacology , ErbB Receptors/physiology , GTP-Binding Proteins/physiology , Proteins/metabolism , Signal Transduction , Animals , Calcium-Calmodulin-Dependent Protein Kinases/metabolism , Cell Line , Chlorocebus aethiops , Electrophoresis, Polyacrylamide Gel , ErbB Receptors/biosynthesis , GRB2 Adaptor Protein , GTP-Binding Proteins/biosynthesis , Guanine Nucleotide Exchange Factors , Humans , Kinetics , Mice , Mutagenesis , Peptide Mapping , Phosphopeptides/chemistry , Phosphopeptides/isolation & purification , Phosphorylation , Phosphoserine/analysis , Phosphothreonine/analysis , Protein Biosynthesis , Proteins/chemistry , Recombinant Fusion Proteins/biosynthesis , Recombinant Proteins/biosynthesis , Recombinant Proteins/chemistry , Recombinant Proteins/metabolism , Sequence Deletion , Sequence Tagged Sites , Tetradecanoylphorbol Acetate/pharmacology , Transfection , ras Guanine Nucleotide Exchange FactorsABSTRACT
Mitogen-activated protein (MAP) kinases mediate the phosphorylation and activation of nuclear transcription factors that regulate cell growth. MAP kinase activation may result from stimulation of either tyrosine-kinase (RTK) receptors, which possess intrinsic tyrosine kinase activity, or G-protein-coupled receptors (GPCR). RTK-mediated mitogenic signalling involves a series of SH2- and SH3-dependent protein-protein interactions between tyrosine-phosphorylated receptor, Shc, Grb2 and Sos, resulting in Ras-dependent MAP kinase activation. The beta gamma subunits of heterotrimeric G proteins (G beta gamma) also mediate Ras-dependent MAP kinase activation by an as-yet unknown mechanism. Here we demonstrate that activation of MAP kinase by Gi-coupled receptors is preceded by the G beta gamma-mediated tyrosine phosphorylation of Shc, leading to an increased functional association between Shc, Grb2 and Sos. Moreover, disruption of the Shc-Grb2-Sos complex blocks G beta gamma-mediated MAP kinase activation, indicating that G beta gamma does not mediate MAP kinase activation by a direct interaction with Sos. These results indicate that G beta gamma-mediated MAP kinase activation is initiated by a tyrosine phosphorylation event and proceeds by a pathway common to both GPCRs and RTKs.
Subject(s)
Adaptor Proteins, Signal Transducing , Adaptor Proteins, Vesicular Transport , GTP-Binding Proteins/metabolism , Protein Kinases/metabolism , Receptor Protein-Tyrosine Kinases/metabolism , Signal Transduction , Cell Line , Enzyme Activation , Epidermal Growth Factor/metabolism , GRB2 Adaptor Protein , Membrane Proteins/metabolism , Phosphorylation , Proteins/metabolism , Recombinant Proteins/metabolism , Shc Signaling Adaptor Proteins , Son of Sevenless Proteins , Tyrosine/metabolismABSTRACT
Cellular Ras proteins are activated primarily by specific guanine-nucleotide releasing factors such as the Son of Sevenless (Sos) proteins. This activation event is thought to occur in response to plasma membrane localization of a complex containing Sos and a small adapter protein Grb2. We have isolated a dominant mutant allele of mSos1 which transforms Rat1 cells, yet is no longer able to bind Grb2. Biochemical experiments reveal that the subcellular distribution of this truncated Sos protein is not altered with respect to the wild type Sos protein. These data argue against a role for Grb2 in the direct recruitment of Sos proteins to the plasma membrane and suggest that Grb2 may function to overcome negative regulation of Sos by its C terminus.
Subject(s)
Adaptor Proteins, Signal Transducing , Proteins/genetics , Proteins/metabolism , Alleles , Amino Acid Sequence , Animals , Base Sequence , Binding Sites , Cell Line , DNA/genetics , Frameshift Mutation , GRB2 Adaptor Protein , Guanine Nucleotide Exchange Factors , Models, Biological , Molecular Sequence Data , Polymerase Chain Reaction , Protein Binding , Rats , Signal Transduction , Transformation, Genetic , ras Guanine Nucleotide Exchange FactorsABSTRACT
DCC (Deleted in Colorectal Cancer) is a putative tumor suppressor gene located on chromosome band 18q21. Allelic deletions of one DCC locus have been found in more than 70% of colorectal carcinomas. Loss of DCC expression has been detected in 80% of all colorectal cancers and in many other types of tumor. DCC is expressed in normal bone marrow and peripheral lymphocytes, nevertheless DCC expression was absent or greatly reduced in 30% of acute leukemias and in 25% of Chronic Myelogenous Leukemias (CML). DCC encodes a transmembrane glycoprotein closely related to the adhesion molecules of the Neural Cell Adhesion Molecule (N-CAM) family. Glycoproteins of this family function like cell surface receptors and are involved in the regulation of many functions including cell recognition and cell differentiation. Highly specialized adhesion molecules participate in the regulation of hemopoiesis by mediating the interactions of hemopoietic cells with the components of the bone marrow microenvironment. Therefore, loss of DCC, as well as loss or alteration of other adhesion receptors, could contribute to leukemogenesis by impairing the interactions of the hemopoietic cells with the bone marrow microenvironment.