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1.
Lancet Reg Health Eur ; 39: 100881, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38803632

RESUMO

Background: Childhood cancer predisposition (ChiCaP) syndromes are increasingly recognized as contributing factors to childhood cancer development. Yet, due to variable availability of germline testing, many children with ChiCaP might go undetected today. We report results from the nationwide and prospective ChiCaP study that investigated diagnostic yield and clinical impact of integrating germline whole-genome sequencing (gWGS) with tumor sequencing and systematic phenotyping in children with solid tumors. Methods: gWGS was performed in 309 children at diagnosis of CNS (n = 123, 40%) or extracranial (n = 186, 60%) solid tumors and analyzed for disease-causing variants in 189 known cancer predisposing genes. Tumor sequencing data were available for 74% (227/309) of patients. In addition, a standardized clinical assessment for underlying predisposition was performed in 95% (293/309) of patients. Findings: The prevalence of ChiCaP diagnoses was 11% (35/309), of which 69% (24/35) were unknown at inclusion (diagnostic yield 8%, 24/298). A second-hit and/or relevant mutational signature was observed in 19/21 (90%) tumors with informative data. ChiCaP diagnoses were more prevalent among patients with retinoblastomas (50%, 6/12) and high-grade astrocytomas (37%, 6/16), and in those with non-cancer related features (23%, 20/88), and ≥2 positive ChiCaP criteria (28%, 22/79). ChiCaP diagnoses were autosomal dominant in 80% (28/35) of patients, yet confirmed de novo in 64% (18/28). The 35 ChiCaP findings resulted in tailored surveillance (86%, 30/35) and treatment recommendations (31%, 11/35). Interpretation: Overall, our results demonstrate that systematic phenotyping, combined with genomics-based diagnostics of ChiCaP in children with solid tumors is feasible in large-scale clinical practice and critically guides personalized care in a sizable proportion of patients. Funding: The study was supported by the Swedish Childhood Cancer Fund and the Ministry of Health and Social Affairs.

2.
Breast Cancer Res ; 15(5): R96, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-24131622

RESUMO

INTRODUCTION: mTOR and its downstream effectors the 4E-binding protein 1 (4EBP1) and the p70 ribosomal S6 kinases (S6K1 and S6K2) are frequently upregulated in breast cancer, and assumed to be driving forces in tumourigenesis, in close connection with oestrogen receptor (ER) networks. Here, we investigated these factors as clinical markers in five different cohorts of breast cancer patients. METHODS: The prognostic significance of 4EBP1, S6K1 and S6K2 mRNA expression was assessed with real-time PCR in 93 tumours from the treatment randomised Stockholm trials, encompassing postmenopausal patients enrolled between 1976 and 1990. Three publicly available breast cancer cohorts were used to confirm the results. Furthermore, the predictive values of 4EBP1 and p4EBP1_S65 protein expression for both prognosis and endocrine treatment benefit were assessed by immunohistochemical analysis of 912 node-negative breast cancers from the Stockholm trials. RESULTS: S6K2 and 4EBP1 mRNA expression levels showed significant correlation and were associated with a poor outcome in all cohorts investigated. 4EBP1 protein was confirmed as an independent prognostic factor, especially in progesterone receptor (PgR)-expressing cancers. 4EBP1 protein expression was also associated with a poor response to endocrine treatment in the ER/PgR positive group. Cross-talk to genomic as well as non-genomic ER/PgR signalling may be involved and the results further support a combination of ER and mTOR signalling targeted therapies. CONCLUSION: This study suggests S6K2 and 4EBP1 as important factors for breast tumourigenesis, interplaying with hormone receptor signalling. We propose S6K2 and 4EBP1 as new potential clinical markers for prognosis and endocrine therapy response in breast cancer.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal/genética , Neoplasias da Mama/genética , Neoplasias da Mama/metabolismo , Regulação Neoplásica da Expressão Gênica , Fosfoproteínas/genética , Proteínas Quinases S6 Ribossômicas 70-kDa/genética , Serina-Treonina Quinases TOR/metabolismo , Antineoplásicos Hormonais , Neoplasias da Mama/tratamento farmacológico , Neoplasias da Mama/mortalidade , Proteínas de Ciclo Celular , Resistencia a Medicamentos Antineoplásicos , Feminino , Amplificação de Genes , Humanos , Avaliação de Resultados da Assistência ao Paciente , Prognóstico , RNA Mensageiro/genética , Recidiva , Estudos Retrospectivos , Tamoxifeno/uso terapêutico
3.
Genes Chromosomes Cancer ; 50(10): 775-87, 2011 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-21748818

RESUMO

The chromosomal region 11q13 is amplified in 15-20% of breast cancers; an event not only associated with estrogen receptor (ER) expression but also implicated in resistance to endocrine therapy. Coamplifications of the 11q13 and 8p12 regions are common, suggesting synergy between the amplicons. The aim was to identify candidate oncogenes in the 11q13 region based on recurrent amplification patterns and correlations to mRNA expression levels. Furthermore, the 11q13/8p12 coamplification and its prognostic value, was evaluated at the DNA and the mRNA levels. Affymetrix 250K NspI arrays were used for whole-genome screening of DNA copy number changes in 29 breast tumors. To identify amplicon cores at 11q13 and 8p12, genomic identification of significant targets in cancer (GISTIC) was applied. The mRNA expression levels of candidate oncogenes in the amplicons [RAD9A, RPS6KB2 (S6K2), CCND1, FGF19, FGF4, FGF3, PAK1, GAB2 (11q13); EIF4EBP1 (4EBP1), PPAPDC1B, and FGFR1 (8p12)] were evaluated using real-time PCR. Resulting data revealed three main amplification cores at 11q13. ER expression was associated with the central 11q13 amplification core, encompassing CCND1, whereas 8p12 amplification/gene expression correlated to S6K2 in a proximal 11q13 core. Amplification of 8p12 and high expression of 4EBP1 or FGFR1 was associated with a poor outcome in the group. In conclusion, single nucleotide polymorphism arrays have enabled mapping of the 11q13 amplicon in breast tumors with high resolution. A proximal 11q13 core including S6K2 was identified as involved in the coamplification/coexpression with 8p12, suggesting synergy between the mTOR targets S6K2 and 4EBP1 in breast cancer development and progression.


Assuntos
Biomarcadores Tumorais/genética , Neoplasias da Mama/genética , Cromossomos Humanos Par 11/genética , Cromossomos Humanos Par 8/genética , Expressão Gênica , Genômica/métodos , Proteínas Adaptadoras de Transdução de Sinal/genética , Neoplasias da Mama/diagnóstico , Neoplasias da Mama/mortalidade , Neoplasias da Mama/patologia , Proteínas de Ciclo Celular , Mapeamento Cromossômico , Cromossomos Humanos Par 11/química , Cromossomos Humanos Par 8/química , Feminino , Amplificação de Genes , Genoma Humano , Estudo de Associação Genômica Ampla , Humanos , Análise de Sequência com Séries de Oligonucleotídeos , Fosfoproteínas/genética , Polimorfismo de Nucleotídeo Único , Prognóstico , Reação em Cadeia da Polimerase em Tempo Real , Proteínas Quinases S6 Ribossômicas 70-kDa/genética , Análise de Sobrevida , Serina-Treonina Quinases TOR/genética
4.
Front Oncol ; 12: 861324, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35982977

RESUMO

Introduction: Since its introduction in standard of care, trastuzumab has revolutionized the treatment of patients with early and late stages of HER2-positive breast cancer. While the initial clinical trials were convincing and lead to major changes in practice, more knowledge on the long-term outcome and tolerability is needed. The present study was designed to assess the survival, prognostic factors and relapse patterns after the implementation of trastuzumab in a real-world cohort. Methods: All cases of HER2-positive breast cancer diagnosed between 2006 and 2014 in the Southeast Healthcare Region of Sweden were retrospectively identified. Medical records were thoroughly reviewed with regard to clinicopathological parameters, treatments, relapse pattern and adverse events. Results: 643 patients were identified and 599 were eligible for analysis. Breast cancer specific survival, distant recurrence free survival and local recurrence free survival were 93.4%, 89.7% and 98.0% for trastuzumab treated patients and 87.4%, 81.6% and 87.4% in patients not treated with trastuzumab, respectively. ER status, nodal status and trastuzumab treatment were all independent prognostic factors in multivariable analysis. No new safety concerns were discovered. Conclusion: The real-world outcome of trastuzumab-treated patients with early HER2-positive breast cancer is similar to what has been previously reported in long-term follow up of prospective clinical trials. ER status, nodal status and trastuzumab treatment are independent prognostic factors for breast cancer specific mortality rate, distant recurrence rate and locoregional recurrence rate in HER2-positive patients in the trastuzumab era.

5.
Biochem Biophys Res Commun ; 410(3): 422-7, 2011 Jul 08.
Artigo em Inglês | MEDLINE | ID: mdl-21669187

RESUMO

Canertinib is a novel ErbB-receptor inhibitor currently in clinical development for the treatment of solid tumors overexpressing ErbB-receptors. We have recently demonstrated that canertinib displays anti-proliferative and pro-apoptotic effects in human myeloid leukemia cells devoid of ErbB-receptors. The mechanism mediating these effects are however unknown. In this study, we show that canertinib is able to act as a multi-kinase inhibitor by inhibition of several intracellular kinases involved in T-cell signaling such as Akt, Erk1/2 and Zap-70, and reduced Lck protein expression in the human T-cell leukemia cell line Jurkat. Treatment with canertinib at a concentration of 2 µM caused accumulation of Jurkat cells in the G(1) cell cycle phase and increased doses induced apoptosis in a time-dependent manner. Apoptotic signs of treated cells were detected by Annexin V staining and cleavage of PARP, caspase-3, -8, -9, -10 and Bid. A subset of the pro-apoptotic signals mediated by canertinib could be significantly reduced by specific caspase inhibitors. Taken together, these results demonstrate the dual ability of canertinib to downregulate important signaling pathways and to activate caspase-mediated intrinsic apoptosis pathway in human T-cell leukemia cells.


Assuntos
Apoptose , Caspases/metabolismo , Leucemia de Células T/enzimologia , Morfolinas/farmacologia , Inibidores de Proteínas Quinases/farmacologia , Humanos , Células Jurkat , Proteína Tirosina Quinase p56(lck) Linfócito-Específica/metabolismo , Proteína Quinase 1 Ativada por Mitógeno/metabolismo , Proteína Quinase 3 Ativada por Mitógeno/metabolismo , Fosforilação/efeitos dos fármacos , Poli(ADP-Ribose) Polimerases/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Receptores Proteína Tirosina Quinases/antagonistas & inibidores , Receptores de Antígenos de Linfócitos T/metabolismo , Proteína-Tirosina Quinase ZAP-70/metabolismo
6.
Biochem Biophys Res Commun ; 414(3): 563-8, 2011 Oct 28.
Artigo em Inglês | MEDLINE | ID: mdl-21982771

RESUMO

The ErbB receptor family has been suggested to constitute a therapeutic target for tumor-specific treatment of malignant melanoma. Here we investigate the effect of the pan-ErbB tyrosine kinase inhibitor canertinib on cell growth and survival in human melanoma cells in vitro and in vivo. Canertinib significantly inhibited growth of cultured melanoma cells, RaH3 and RaH5, in a dose-dependent manner as determined by cell counting. Half-maximum growth inhibitory dose (IC(50)) was approximately 0.8 µM and by 5 µM both cell lines were completely growth-arrested within 72 h of treatment. Incubation of exponentially growing RaH3 and RaH5 with 1 µM canertinib accumulated the cells in the G(1)-phase of the cell cycle within 24h of treatment without induction of apoptosis as determined by flow cytometry. Immunoblot analysis showed that 1 µM canertinib inhibited ErbB1-3 receptor phosphorylation with a concomitant decrease of Akt-, Erk1/2- and Stat3 activity in both cell lines. In contrast to the cytostatic effect observed at doses ≤ 5µM canertinib, higher concentrations induced apoptosis as demonstrated by the Annexin V method and Western blot analysis of PARP cleavage. Furthermore, canertinib significantly inhibited growth of RaH3 and RaH5 melanoma xenografts in nude mice. Pharmacological targeting of the ErbB receptors may prove successful in the treatment of patients with metastatic melanoma.


Assuntos
Antineoplásicos/uso terapêutico , Apoptose/efeitos dos fármacos , Melanoma/tratamento farmacológico , Morfolinas/uso terapêutico , Inibidores de Proteínas Quinases/uso terapêutico , Proteínas Tirosina Quinases/antagonistas & inibidores , Receptor ErbB-2/antagonistas & inibidores , Animais , Proliferação de Células/efeitos dos fármacos , Feminino , Humanos , Melanoma/patologia , Camundongos , Camundongos Nus , Proteína Quinase 1 Ativada por Mitógeno/antagonistas & inibidores , Proteína Quinase 3 Ativada por Mitógeno/antagonistas & inibidores , Fosforilação/efeitos dos fármacos , Proteínas Proto-Oncogênicas c-akt/antagonistas & inibidores , Receptor ErbB-3/antagonistas & inibidores , Fator de Transcrição STAT3/metabolismo
7.
Biochem Biophys Res Commun ; 393(1): 6-10, 2010 Feb 26.
Artigo em Inglês | MEDLINE | ID: mdl-20096663

RESUMO

Epidermal growth factor (EGF) receptor tyrosine kinase inhibitors have recently been shown to display anti-neoplastic effects in human malignant myeloid cells. Our study was initiated in order to determine the effect of the pan-ErbB receptor tyrosine kinase inhibitor, canertinib (CI-1033), on growth and survival of human leukemia (HL-60 and U-937) cells. We show that treatment of HL-60 and U-937 cells with canertinib significantly inhibits growth of both cell lines in a dose-dependent manner; half maximal effective dose (IC(50)) in HL-60 and U-937 cells was approximately 2.5 microM and 1.0 microM, respectively. Treatment with 2 microM canertinib promoted a G(1) cell cycle arrest, whereas doses of 5 microM or more induced apoptosis as determined by the Annexin V method and cleavage of poly-(ADP-ribose) polymerase (PARP). HL-60 and U-937 cells lacked EGF-receptor transcript but expressed ErbB2-4 mRNA as determined by RT-PCR. However, none of the corresponding ErbB-receptor proteins could be detected by Western blot analysis. We conclude that canertinib induces apoptosis in HL-60 and U-937 cells devoid of functional ErbB1-4 receptors. Our results suggest that canertinib could be of potential clinical interest in the treatment of acute myeloid leukemia.


Assuntos
Antineoplásicos/farmacologia , Apoptose , Leucemia Mieloide Aguda/enzimologia , Morfolinas/farmacologia , Inibidores de Proteínas Quinases/farmacologia , Receptor ErbB-2/antagonistas & inibidores , Fase G1/efeitos dos fármacos , Células HL-60 , Humanos , Poli(ADP-Ribose) Polimerases/metabolismo
10.
Oncol Lett ; 17(3): 3371-3381, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30867772

RESUMO

Trastuzumab has markedly improved the treatment and long-term prognosis of patients with HER2-positive breast cancer. A frequent clinical challenge in patients with relapsing and/or metastatic disease is de novo or acquired trastuzumab resistance, and to date no predictive biomarkers for palliative trastuzumab have been established. In the present study, the prognostic values of factors involved in the HER2-associated PI3K/Akt signalling pathway were explored. The first 46 consecutive patients treated at the Department of Oncology, Linköping University Hospital between 2000 and 2007 with trastuzumab for HER2-positive metastatic breast cancer were retrospectively included. The gene copy number variation and protein expression of several components of the PI3K/Akt pathway were assessed in the tumour tissue and biopsy samples using droplet digital polymerase chain reaction and immunohistochemistry. Patients with tumours displaying a high-grade ERBB2 (HER2) amplification level of ≥6 copies had a significantly improved overall survival hazard ratio [(HR)=0.4; 95%, confidence interval (CI): 0.2-0.9] and progression-free survival (HR=0.3; 95% CI: 0.1-0.7) compared with patients with tumours harbouring fewer ERBB2 copies. High-grade ERBB2 amplification was significantly associated with the development of central nervous system metastases during palliative treatment. Copy gain (≥3 copies) of the gene encoding the tyrosine phosphatase PTPN2 was associated with a shorter overall survival (HR=2.0; 95% CI: 1.0-4.0) and shorter progression-free survival (HR=2.1; 95% CI: 1.0-4.1). In conclusion, high ERBB2 amplification level is a potential positive prognostic factor in trastuzumab-treated HER2-positive metastatic breast cancer, whereas PTPN2 gain is a potential negative prognostic factor. Further studies are warranted on the role of PTPN2 in HER2 signalling.

11.
Oncotarget ; 6(12): 10134-45, 2015 Apr 30.
Artigo em Inglês | MEDLINE | ID: mdl-25912307

RESUMO

Salinomycin has been used as treatment for malignant tumors in a small number of humans, causing far less side effects than standard chemotherapy. Several studies show that Salinomycin targets cancer-initiating cells (cancer stem cells, or CSC) resistant to conventional therapies. Numerous studies show that Salinomycin not only reduces tumor volume, but also decreases tumor recurrence when used as an adjuvant to standard treatments. In this study we show that starvation triggered different stress responses in cancer cells and primary normal cells, which further improved the preferential targeting of cancer cells by Salinomycin. Our in vitro studies further demonstrate that the combined use of 2-Fluoro 2-deoxy D-glucose, or 2-deoxy D-glucose with Salinomycin is lethal in cancer cells while the use of Oxamate does not improve cell death-inducing properties of Salinomycin. Furthermore, we show that treatment of cancer cells with Salinomycin under starvation conditions not only increases the apoptotic caspase activity, but also diminishes the protective autophagy normally triggered by the treatment with Salinomycin alone. Thus, this study underlines the potential use of Salinomycin as a cancer treatment, possibly in combination with short-term starvation or starvation-mimicking pharmacologic intervention.


Assuntos
Hipóxia Celular/fisiologia , Glucose/administração & dosagem , Neoplasias/tratamento farmacológico , Células-Tronco Neoplásicas/metabolismo , Piranos/antagonistas & inibidores , Piranos/farmacologia , Autofagia/efeitos dos fármacos , Morte Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Ensaios de Seleção de Medicamentos Antitumorais , Glucose/metabolismo , Humanos , Neoplasias/metabolismo , Neoplasias/patologia , Células-Tronco Neoplásicas/efeitos dos fármacos , Células-Tronco Neoplásicas/patologia
12.
Oncotarget ; 6(18): 16663-73, 2015 Jun 30.
Artigo em Inglês | MEDLINE | ID: mdl-26143636

RESUMO

Telomerase reverse transcriptase (TERT) activity is up-regulated in several types of tumors including glioblastoma (GBM). In the present study, 128 primary glioblastoma patients were examined for single nucleotide polymorphisms of TERT in blood and in 92 cases for TERT promoter mutations in tumors. TERT promoter mutations were observed in 86% of the tumors and of these, C228T (-124 bp upstream start codon) was detected in 75% and C250T (-146 bp) in 25% of cases. TERT promoter mutations were associated with shorter overall survival (11 vs. 20 months p = 0.002 and 12 vs. 20, p = 0.04 for C228T and C250T, respectively). The minor alleles of rs2736100 and rs10069690 SNP's, located in intron 2 and the promotor regions, respectively, were associated with an increased risk of developing GBM (p = 0.004 and 0.001). GBM patients having both TERT promoter mutations and being homozygous carriers of the rs2853669 C-allele displayed significantly shorter overall survival than those with the wild type allele. The rs2853669 SNP is located in a putative Ets2 binding site in the promoter (-246 bp upstream start codon) close to the C228T and C250T mutation hot spots. Interleukin-6 (IL-6) expression regulated by TERT promoter status and polymorphism, what leads us to think that TERT and IL-6 plays a significant role in GBM, where specific SNPs increase the risk of developing GBM while the rs2853669 SNP and specific mutations in the TERT promoter of the tumor lead to shorter survival.


Assuntos
Biomarcadores Tumorais/genética , Glioblastoma/genética , Regiões Promotoras Genéticas/genética , Telomerase/genética , Sítios de Ligação/genética , Feminino , Glioblastoma/mortalidade , Glioblastoma/patologia , Humanos , Interleucina-1beta/genética , Interleucina-6/genética , Isocitrato Desidrogenase/genética , Masculino , Pessoa de Meia-Idade , Polimorfismo de Nucleotídeo Único/genética , Prognóstico , RNA Mensageiro/biossíntese , Complexo Shelterina , Proteínas de Ligação a Telômeros/genética , Fator de Necrose Tumoral alfa/genética
13.
PLoS One ; 10(12): e0145013, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26698305

RESUMO

BACKGROUND: The AKT/mTORC1/S6K pathway is frequently overstimulated in breast cancer, constituting a promising therapeutic target. The benefit from mTOR inhibitors varies, likely as a consequence of tumour heterogeneity, and upregulation of several compensatory feed-back mechanisms. The mTORC1 downstream effectors S6K1, S6K2, and 4EBP1 are amplified and overexpressed in breast cancer, associated with a poor outcome and divergent endocrine treatment benefit. S6K1 and S6K2 share high sequence homology, but evidence of partly distinct biological functions is emerging. The aim of this work was to explore possible different roles and treatment target potentials of S6K1 and S6K2 in breast cancer. MATERIALS AND METHODS: Whole-genome expression profiles were compared for breast tumours expressing high levels of S6K1, S6K2 or 4EBP1, using public datasets, as well as after in vitro siRNA downregulation of S6K1 and/or S6K2 in ZR751 breast cancer cells. In silico homology modelling of the S6K2 kinase domain was used to evaluate its possible structural divergences to S6K1. RESULTS: Genome expression profiles were highly different in S6K1 and S6K2 high tumours, whereas S6K2 and 4EBP1 profiles showed significant overlaps, both correlated to genes involved in cell cycle progression, among these the master regulator E2F1. S6K2 and 4EBP1 were inversely associated with IGF1 levels, and their prognostic value was shown to be restricted to tumours positive for IGFR and/or HER2. In vitro, S6K1 and S6K2 silencing resulted in upregulation of genes in the mTORC1 and mTORC2 complexes. Isoform-specific silencing also showed distinct patterns, e.g. S6K2 downregulation lead to upregulation of several cell cycle associated genes. Structural analyses of the S6K2 kinase domain showed unique structure patterns, deviating from those of S6K1, facilitating the development of isoform-specific inhibitors. Our data support emerging proposals of distinct biological features of S6K1 and S6K2, suggesting their importance as separate oncogenes and clinical markers, where specific targeting in different breast cancer subtypes could facilitate further individualised therapies.


Assuntos
Biomarcadores Tumorais/genética , Neoplasias da Mama/genética , Perfilação da Expressão Gênica , Proteínas Quinases S6 Ribossômicas 70-kDa/genética , Proteínas Quinases S6 Ribossômicas 90-kDa/genética , Serina-Treonina Quinases TOR/genética , Neoplasias da Mama/mortalidade , Neoplasias da Mama/patologia , Feminino , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Modelos Moleculares , Conformação Proteica , RNA Mensageiro/genética , Reação em Cadeia da Polimerase em Tempo Real , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Proteínas Quinases S6 Ribossômicas 70-kDa/química , Proteínas Quinases S6 Ribossômicas 90-kDa/química , Taxa de Sobrevida , Células Tumorais Cultivadas
14.
Melanoma Res ; 19(3): 156-66, 2009 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-19434003

RESUMO

Members of the epidermal growth factor (EGF) family of structurally related tyrosine kinase receptors, known as the ErbB receptors (EGFR/ErbB1/HER1, ErbB2/HER2/neu, ErbB3/HER3 and ErbB4/HER4) and their respective ligands, have been suggested to be involved in the development and progression of malignant melanoma. Here we investigate the effects of the ErbB1 tyrosine kinase inhibitor gefitinib (ZD1839, Iressa) on human malignant melanoma cells (RaH3 and RaH5) in vitro. ZD1839 inhibited proliferation of exponentially growing RaH3 and RaH5 cells in a dose-dependent manner with a half-maximally effective dose of 3.5 and 2.0 micromol/l, respectively. Cell growth was inhibited at 0.1 micromol/l ZD1839 in both cell lines. Maximal inhibition was accomplished at 10 micromol/l ZD1839; however, the effect was not complete as both cell lines showed a continuous slow growth during the treatment period. Flow cytometry analysis of cell-cycle distribution showed that ZD1839 treatment caused accumulation of RaH3 and RaH5 cells in the G1 phase. The growth arrest induced by ZD1839 coincided with upregulation of the cyclin-dependent kinase inhibitor p27 KIP 1. There was no increase in apoptosis as determined by analysis of plasma phosphatidyl serine redistribution. Western blot analysis revealed that ZD1839 substantially reduced tyrosine phosphorylation of ErbB1 as well as ErbB2 and ErbB3. This was accompanied by a concomitant decrease in Akt-phosphorylation, Erk1/2-phosphorylation, and Stat3-phosphorylation. Our results show that ZD1839 interferes with the growth of human malignant melanoma cells by cytostatic effects. These findings indicate the possible use of ErbB receptor kinase inhibitors as a novel treatment strategy in malignant melanoma.


Assuntos
Antineoplásicos/farmacologia , Melanoma/enzimologia , Inibidores de Proteínas Quinases/farmacologia , Quinazolinas/farmacologia , Receptor ErbB-2/antagonistas & inibidores , Neoplasias Cutâneas/enzimologia , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Inibidor de Quinase Dependente de Ciclina p27/agonistas , Inibidor de Quinase Dependente de Ciclina p27/metabolismo , MAP Quinases Reguladas por Sinal Extracelular/antagonistas & inibidores , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Gefitinibe , Humanos , Melanoma/patologia , Fosforilação/efeitos dos fármacos , Proteínas Proto-Oncogênicas c-akt/antagonistas & inibidores , Proteínas Proto-Oncogênicas c-akt/metabolismo , Receptor ErbB-2/metabolismo , Fator de Transcrição STAT3/antagonistas & inibidores , Fator de Transcrição STAT3/metabolismo , Neoplasias Cutâneas/patologia
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