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1.
Ann Oncol ; 33(10): 1029-1040, 2022 10.
Artigo em Inglês | MEDLINE | ID: mdl-35872166

RESUMO

BACKGROUND: Allele-specific KRAS inhibitors are an emerging class of cancer therapies. KRAS-mutant (KRASMUT) non-small-cell lung cancers (NSCLCs) exhibit heterogeneous outcomes, driven by differences in underlying biology shaped by co-mutations. In contrast to KRASG12C NSCLC, KRASG12D NSCLC is associated with low/never-smoking status and is largely uncharacterized. PATIENTS AND METHODS: Clinicopathologic and genomic information were collected from patients with NSCLCs harboring a KRAS mutation at the Dana-Farber Cancer Institute (DFCI), Memorial Sloan Kettering Cancer Center, MD Anderson Cancer Center, and Imperial College of London. Multiplexed immunofluorescence for CK7, programmed cell death protein 1 (PD-1), programmed death-ligand 1 (PD-L1), Foxp3, and CD8 was carried out on a subset of samples with available tissue at the DFCI. Clinical outcomes to PD-(L)1 inhibition ± chemotherapy were analyzed according to KRAS mutation subtype. RESULTS: Of 2327 patients with KRAS-mutated (KRASMUT) NSCLC, 15% (n = 354) harbored KRASG12D. Compared to KRASnon-G12D NSCLC, KRASG12D NSCLC had a lower pack-year (py) smoking history (median 22.5 py versus 30.0 py, P < 0.0001) and was enriched in never smokers (22% versus 5%, P < 0.0001). KRASG12D had lower PD-L1 tumor proportion score (TPS) (median 1% versus 5%, P < 0.01) and lower tumor mutation burden (TMB) compared to KRASnon-G12D (median 8.4 versus 9.9 mt/Mb, P < 0.0001). Of the samples which underwent multiplexed immunofluorescence, KRASG12D had lower intratumoral and total CD8+PD1+ T cells (P < 0.05). Among 850 patients with advanced KRASMUT NSCLC who received PD-(L)1-based therapies, KRASG12D was associated with a worse objective response rate (ORR) (15.8% versus 28.4%, P = 0.03), progression-free survival (PFS) [hazard ratio (HR) 1.51, 95% confidence interval (CI) 1.45-2.00, P = 0.003], and overall survival (OS; HR 1.45, 1.05-1.99, P = 0.02) to PD-(L)1 inhibition alone but not to chemo-immunotherapy combinations [ORR 30.6% versus 35.7%, P = 0.51; PFS HR 1.28 (95%CI 0.92-1.77), P = 0.13; OS HR 1.36 (95%CI 0.95-1.96), P = 0.09] compared to KRASnon-G12D. CONCLUSIONS: KRASG12D lung cancers harbor distinct clinical, genomic, and immunologic features compared to other KRAS-mutated lung cancers and worse outcomes to PD-(L)1 blockade. Drug development for KRASG12D lung cancers will have to take these differences into account.


Assuntos
Carcinoma Pulmonar de Células não Pequenas , Neoplasias Pulmonares , Antígeno B7-H1 , Carcinoma Pulmonar de Células não Pequenas/tratamento farmacológico , Carcinoma Pulmonar de Células não Pequenas/genética , Carcinoma Pulmonar de Células não Pequenas/patologia , Fatores de Transcrição Forkhead , Genômica , Humanos , Neoplasias Pulmonares/tratamento farmacológico , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/patologia , Mutação , Receptor de Morte Celular Programada 1 , Proteínas Proto-Oncogênicas p21(ras)/genética
2.
Ann Oncol ; 31(6): 807-814, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32171752

RESUMO

BACKGROUND: Programmed cell death ligand 1 (PD-L1) tumor proportion score (TPS) is the primary clinically-available biomarker of response to immunotherapy in non-small-cell lung cancer (NSCLC), but factors associated with PD-L1 expression are not well understood. MATERIALS AND METHODS: Consecutive nonsquamous NSCLCs with successful PD-L1 assessment and targeted next-generation sequencing were included in this retrospective study. Clinicopathological characteristics, gene mutations, and copy number changes in gene and chromosomal arms were compared among three PD-L1 expression groups: negative (TPS < 1%), low (TPS 1%-49%), and high (TPS ≥ 50%). A Q-value <0.25 was considered significant after multiple comparisons correction. RESULTS: A total of 909 nonsquamous NSCLCs were included. High PD-L1 expression compared with low and negative PD-L1 expression was associated with increased tobacco exposure (median pack-years: 25 versus 20 versus 20, respectively; P = 0.01), advanced stage at diagnosis (76% versus 67% versus 61% with advanced stage of disease, respectively; P < 0.001), and higher tumor mutational burden (TMB) (median 12.2 versus 10.6 versus 10.6 mutations/megabase, respectively; P < 0.001). Negative PD-L1 expression when compared with high PD-L1 expression was associated with: mutations in STK11 (19% versus 5%; Q < 0.001), EGFR (22% versus 11%; Q < 0.001), CTNNB1 (4.3% versus 0.4%; Q = 0.04), APC (5% versus 1%; Q = 0.17), and SMARCA4 (9% versus 4%; Q = 0.20); copy number loss of CD274 (PD-L1, 28% versus 6%; Q < 0.001), PDCD1LG2 (PD-L2, 28% versus 6%; Q < 0.001), and JAK2 genes (27% versus 7%; Q < 0.001), loss of chromosomal arm 9p (23% versus 10%; Q = 0.04), and gain of 1q (46% versus 21%; Q < 0.001). High PD-L1 expression compared with negative PD-L1 expression was associated with copy number gain of CD274 (11% versus 3%; Q = 0.01) and PDCD1LG2 (11% versus 3%; Q = 0.01). NSCLCs with CD274 loss, compared with those without loss, had a lower response rate (23% versus 9%; P = 0.006) and shorter progression-free survival (3.3 versus 2.0 months; P = 0.002) on immunotherapy. CONCLUSIONS: PD-L1 expression is associated with specific genomic alterations and clinicopathologic characteristics in nonsquamous NSCLC.


Assuntos
Carcinoma Pulmonar de Células não Pequenas , Neoplasias Pulmonares , Apoptose , Antígeno B7-H1/genética , Carcinoma Pulmonar de Células não Pequenas/genética , Genômica , Humanos , Ligantes , Neoplasias Pulmonares/genética , Estudos Retrospectivos
3.
Gynecol Oncol ; 134(3): 599-606, 2014 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-24995579

RESUMO

PURPOSE: Our previously reported 29-gene expression signature identified an aggressive subgroup of endometrial cancer patients with PI3K activation. We here wanted to validate these findings by independent patient series. PATIENTS AND METHODS: The 29-gene expression signature was assessed in fresh frozen tumor tissue from 280 primary endometrial carcinomas (three independent cohorts), 19 metastatic lesions and in 333 primary endometrial carcinomas using TCGA data, and expression was related to clinico-pathologic features and survival. The 29-gene signature was assessed by real-time quantitative PCR, DNA oligonucleotide microarrays, or RNA sequencing. PI3K alterations were assessed by immunohistochemistry, DNA microarrays, DNA sequencing, SNP arrays or fluorescence in situ hybridization. A panel of markers of epithelial-mesenchymal transition (EMT) was also correlated to the 29-gene signature score. RESULTS: High 29-gene Endometrial Carcinoma Recurrence Score (ECARS) values consistently validated to identify patients with aggressive clinico-pathologic phenotype and reduced survival. Within the presumed favorable subgroups of low grade, endometrioid tumors confined to the uterus, high ECARS still predicted a poor prognosis. The score was higher in metastatic compared to primary lesions (P<0.001) and was significantly associated with potential measures of PI3K activation, markers of EMT and vascular invasion as an indicator of metastatic spread (all P<0.001). CONCLUSIONS: ECARS validates to identify aggressive endometrial carcinomas in multiple, independent patients cohorts. The higher signature score in metastatic compared to primary lesions, and the potential link to PI3K activation and EMT, support further studies of ECARS in relation to response to PI3K and EMT inhibitors in clinical trials of metastatic endometrial carcinoma.


Assuntos
Neoplasias do Endométrio/genética , Neoplasias do Endométrio/patologia , Transição Epitelial-Mesenquimal , Recidiva Local de Neoplasia/genética , Recidiva Local de Neoplasia/patologia , Fosfatidilinositol 3-Quinases/genética , Biomarcadores Tumorais , Neoplasias do Endométrio/epidemiologia , Feminino , Humanos
4.
Nat Genet ; 19(2): 182-6, 1998 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-9620778

RESUMO

Activation of telomerase, the enzyme that synthesizes the telomere ends of linear chromosomes, has been implicated in human cell immortalization and cancer cell pathogenesis. Enzyme activity is undetectable in most normal cells and tissues, but present in immortal cells and cancer tissues. While expression of TERC, the RNA component of telomerase, is widespread, the restricted expression pattern of TERT, the telomerase catalytic subunit gene, is correlated with telomerase activity, and its ectopic expression in telomerase-negative cells is sufficient to reconstitute telomerase activity and extend cellular lifespan. We have used in situ hybridization to study TERT expression at the single-cell level in normal tissues and in various stages of tumour progression. In normal tissues, including some that are known to be telomerase-negative, TERT mRNA was present in specific subsets of cells thought to have long-term proliferative capacity. This included mitotically inactive breast lobular epithelium in addition to some actively regenerating cells such as the stratum basale of the skin. TERT expression appeared early during tumorigenesis in vivo, beginning with early pre-invasive changes in human breast and colon tissues and increasing gradually during progression, both in the amount of TERT mRNA present within individual cells and in the number of expressing cells within a neoplastic lesion. The physiological expression of TERT within normal epithelial cells that retain proliferative potential and its presence at the earliest stages of tumorigenesis have implications for the regulation of telomerase expression and for the identification of cells that may be targets for malignant transformation.


Assuntos
Transformação Celular Neoplásica/metabolismo , Lesões Pré-Cancerosas/genética , Biossíntese de Proteínas , Proteínas/genética , RNA não Traduzido , Telomerase/metabolismo , Neoplasias da Mama/metabolismo , Neoplasias da Mama/patologia , Catálise , Neoplasias do Colo/enzimologia , Neoplasias do Colo/patologia , Proteínas de Ligação a DNA , Ativação Enzimática , Feminino , Expressão Gênica , Humanos , Hibridização In Situ , RNA/metabolismo , RNA Longo não Codificante , RNA Mensageiro/metabolismo , Células Tumorais Cultivadas
5.
Proc Natl Acad Sci U S A ; 106(12): 4834-9, 2009 Mar 24.
Artigo em Inglês | MEDLINE | ID: mdl-19261849

RESUMO

Although 75% of endometrial cancers are treated at an early stage, 15% to 20% of these recur. We performed an integrated analysis of genome-wide expression and copy-number data for primary endometrial carcinomas with extensive clinical and histopathological data to detect features predictive of recurrent disease. Unsupervised analysis of the expression data distinguished 2 major clusters with strikingly different phenotypes, including significant differences in disease-free survival. To identify possible mechanisms for these differences, we performed a global genomic survey of amplifications, deletions, and loss of heterozygosity, which identified 11 significantly amplified and 13 significantly deleted regions. Amplifications of 3q26.32 harboring the oncogene PIK3CA were associated with poor prognosis and segregated with the aggressive transcriptional cluster. Moreover, samples with PIK3CA amplification carried signatures associated with in vitro activation of PI3 kinase (PI3K), a signature that was shared by aggressive tumors without PIK3CA amplification. Tumors with loss of PTEN expression or PIK3CA overexpression that did not have PIK3CA amplification also shared the PI3K activation signature, high protein expression of the PI3K pathway member STMN1, and an aggressive phenotype in test and validation datasets. However, mutations of PTEN or PIK3CA were not associated with the same expression profile or aggressive phenotype. STMN1 expression had independent prognostic value. The results affirm the utility of systematic characterization of the cancer genome in clinically annotated specimens and suggest the particular importance of the PI3K pathway in patients who have aggressive endometrial cancer.


Assuntos
Neoplasias do Endométrio/enzimologia , Neoplasias do Endométrio/genética , Perfilação da Expressão Gênica , Regulação Neoplásica da Expressão Gênica , Genoma Humano/genética , Fosfatidilinositol 3-Quinases/metabolismo , Biomarcadores Tumorais/metabolismo , Classe I de Fosfatidilinositol 3-Quinases , Análise por Conglomerados , Neoplasias do Endométrio/diagnóstico , Neoplasias do Endométrio/patologia , Ativação Enzimática , Feminino , Dosagem de Genes , Humanos , Perda de Heterozigosidade/genética , Prognóstico , Proteínas Proto-Oncogênicas/metabolismo , Proteínas Proto-Oncogênicas p21(ras) , Estatmina/metabolismo , Análise de Sobrevida , Proteínas ras/metabolismo
6.
Nat Med ; 5(10): 1164-70, 1999 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-10502820

RESUMO

Telomerase is a ribonucleoprotein enzyme that maintains the protective structures at the ends of eukaryotic chromosomes, called telomeres. In most human somatic cells, telomerase expression is repressed, and telomeres shorten progressively with each cell division. In contrast, most human tumors express telomerase, resulting in stabilized telomere length. These observations indicate that telomere maintenance is essential to the proliferation of tumor cells. We show here that expression of a mutant catalytic subunit of human telomerase results in complete inhibition of telomerase activity, reduction in telomere length and death of tumor cells. Moreover, expression of this mutant telomerase eliminated tumorigenicity in vivo. These observations demonstrate that disruption of telomere maintenance limits cellular lifespan in human cancer cells, thus validating human telomerase reverse transcriptase as an important target for the development of anti-neoplastic therapies.


Assuntos
Mutação , Neoplasias Experimentais/prevenção & controle , RNA , Telomerase/antagonistas & inibidores , Telomerase/genética , Apoptose , Neoplasias da Mama , Domínio Catalítico/genética , Divisão Celular , Neoplasias do Colo , Proteínas de Ligação a DNA , Desenho de Fármacos , Feminino , Vetores Genéticos , Humanos , Neoplasias Experimentais/enzimologia , Neoplasias Ovarianas , Retroviridae/genética , Inibidores da Transcriptase Reversa , Telômero/metabolismo , Células Tumorais Cultivadas
7.
J Pathol ; 217(1): 65-72, 2009 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-18932182

RESUMO

Acquired chromosomal aberrations play an important role in tumour development and progression. Such genetic alterations occur in a significant proportion of non-small cell lung carcinomas (NSCLCs) and include amplification of 14q13.3, which contains the TTF1 gene. We asked whether TTF1 amplification is associated with increased TTF1 protein expression in NSCLCs, and whether TTF1 is associated with clinicopathological features, including patient survival. We used a FISH assay and quantitative immunohistochemical staining to interrogate a population-based cohort of 538 NSCLCs from Swiss patients for TTF1 amplification and protein expression. We found TTF1 amplification in approximately 13% of adenocarcinomas (ACs) and in approximately 9% of squamous cell carcinomas (SCCs) and TTF1 amplification was associated with increased TTF1 protein expression. High-level TTF1 expression was significantly associated with smaller tumour size, female gender and longer overall survival only among ACs (median survival 82 versus 28 months; p = 0.002). On multivariate analysis, high TTF1 expression was an independent predictor of favourable prognosis in patients with AC [hazard ratio, 0.56 (95% CI 0.38-0.83); p = 0.008]. We conclude that TTF1 amplification is a mechanism of high-level TTF1 expression in a subset of NSCLCs. When expressed at high levels, this routinely used diagnostic marker is also an independent biomarker of favourable prognosis in AC.


Assuntos
Biomarcadores Tumorais/metabolismo , Carcinoma Pulmonar de Células não Pequenas/metabolismo , Proteínas de Ligação a DNA/metabolismo , Neoplasias Pulmonares/metabolismo , Adenocarcinoma/genética , Adenocarcinoma/metabolismo , Adenocarcinoma/patologia , Idoso , Biomarcadores Tumorais/genética , Carcinoma Pulmonar de Células não Pequenas/genética , Carcinoma Pulmonar de Células não Pequenas/patologia , Carcinoma de Células Escamosas/genética , Carcinoma de Células Escamosas/metabolismo , Carcinoma de Células Escamosas/patologia , Proteínas de Ligação a DNA/genética , Feminino , Amplificação de Genes , Humanos , Hibridização in Situ Fluorescente , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/patologia , Masculino , Pessoa de Meia-Idade , Estadiamento de Neoplasias , Prognóstico , Estudos Retrospectivos , Análise de Sobrevida , Neoplasias da Glândula Tireoide/genética , Neoplasias da Glândula Tireoide/metabolismo , Fatores de Transcrição
8.
Oncogene ; 26(34): 5023-7, 2007 Jul 26.
Artigo em Inglês | MEDLINE | ID: mdl-17311002

RESUMO

Mutations in the ERBB2 gene were recently found in approximately 2% of primary non-small cell lung cancer (NSCLC) specimens; however, little is known about the functional consequences and the relevance to responsiveness to targeted drugs for most of these mutations. Here, we show that the major lung cancer-derived ERBB2 mutants, including the most frequent mutation, A775insYVMA, lead to oncogenic transformation in a cellular assay. Murine cells transformed with these mutants were relatively resistant to the reversible epidermal growth factor receptor (EGFR) inhibitor erlotinib, resembling the resistant phenotype found in cells carrying the homologous mutations in exon 20 of EGFR. However, the same cells were highly sensitive to the irreversible dual-specificity EGFR/ERBB2 kinase inhibitor HKI-272, as were those overexpressing wild-type ERBB2. Finally, the NSCLC cell line, Calu-3, overexpressing wild-type ERBB2 owing to a high-level amplification of the ERBB2 gene were highly sensitive to HKI-272. These results provide a rationale for treatment of patients with ERBB2-mutant or ERBB2-amplified lung tumors with HKI-272.


Assuntos
Antineoplásicos/farmacologia , Carcinoma Pulmonar de Células não Pequenas/genética , Genes erbB-2 , Neoplasias Pulmonares/genética , Mutação , Inibidores de Proteínas Quinases/farmacologia , Quinolinas/farmacologia , Receptor ErbB-2/antagonistas & inibidores , Carcinoma Pulmonar de Células não Pequenas/enzimologia , Linhagem Celular Tumoral , Transformação Celular Neoplásica/genética , Receptores ErbB/antagonistas & inibidores , Amplificação de Genes , Humanos , Neoplasias Pulmonares/enzimologia
9.
Br J Cancer ; 99(2): 245-52, 2008 Jul 22.
Artigo em Inglês | MEDLINE | ID: mdl-18594528

RESUMO

Somatic mutations of LKB1 tumour suppressor gene have been detected in human cancers including non-small cell lung cancer (NSCLC). The relationship between LKB1 mutations and clinicopathological characteristics and other common oncogene mutations in NSCLC is inadequately described. In this study we evaluated tumour specimens from 310 patients with NSCLC including those with adenocarcinoma, adenosquamous carcinoma, and squamous cell carcinoma histologies. Tumours were obtained from patients of US (n=143) and Korean (n=167) origin and screened for LKB1, KRAS, BRAF, and EGFR mutations using RT-PCR-based SURVEYOR-WAVE method followed by Sanger sequencing. We detected mutations in the LKB1 gene in 34 tumours (11%). LKB1 mutation frequency was higher in NSCLC tumours of US origin (17%) compared with 5% in NSCLCs of Korean origin (P=0.001). They tended to occur more commonly in adenocarcinomas (13%) than in squamous cell carcinomas (5%) (P=0.066). LKB1 mutations associated with smoking history (P=0.007) and KRAS mutations (P=0.042) were almost mutually exclusive with EGFR mutations (P=0.002). The outcome of stages I and II NSCLC patients treated with surgery alone did not significantly differ based on LKB1 mutation status. Our study provides clinical and molecular characteristics of NSCLC, which harbour LKB1 mutations.


Assuntos
Povo Asiático/genética , Carcinoma Pulmonar de Células não Pequenas/genética , Genes Supressores de Tumor , Neoplasias Pulmonares/genética , Mutação , Proteínas Serina-Treonina Quinases/genética , População Branca/genética , Quinases Proteína-Quinases Ativadas por AMP , Carcinoma Pulmonar de Células não Pequenas/enzimologia , Carcinoma Pulmonar de Células não Pequenas/etnologia , Carcinoma Pulmonar de Células não Pequenas/patologia , Linhagem Celular Tumoral , Receptores ErbB/genética , Genes ras , Predisposição Genética para Doença , Humanos , Neoplasias Pulmonares/enzimologia , Neoplasias Pulmonares/etnologia , Neoplasias Pulmonares/patologia , Proteínas Proto-Oncogênicas B-raf/genética
10.
Mol Cell Biol ; 14(3): 2077-86, 1994 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-8114739

RESUMO

A family of vertebrate cdc2-related kinases has been identified, and these kinases are candidates for roles in cell cycle regulation. Here, we show that the human PLSTIRE gene product is a novel cyclin-dependent kinase, cdk6. The cdk6 kinase is associated with cyclins D1, D2, and D3 in lysates of human cells and is activated by coexpression with D-type cyclins in Sf9 insect cells. Furthermore, we demonstrate that endogenous cdk6 from human cell extracts is an active kinase which can phosphorylate pRB, the product of the retinoblastoma tumor suppressor gene. The activation of cdk6 kinase occurs during mid-G1 in phytohemagglutinin-stimulated T cells, well prior to the activation of cdk2 kinase. This timing suggests that cdk6, and by analogy its homolog cdk4, links growth factor stimulation with the onset of cell cycle progression.


Assuntos
Ciclo Celular , Quinases Ciclina-Dependentes , Ciclinas/metabolismo , Proteínas Oncogênicas/metabolismo , Proteínas Quinases/metabolismo , Proteínas Proto-Oncogênicas , Sequência de Aminoácidos , Complexo Antígeno-Anticorpo , Linhagem Celular , Ciclina D1 , Ciclina D2 , Ciclina D3 , Quinase 4 Dependente de Ciclina , Quinase 6 Dependente de Ciclina , Ativação Enzimática , Humanos , Ativação Linfocitária , Substâncias Macromoleculares , Dados de Sequência Molecular , Mapeamento de Peptídeos , Peptídeos/química , Peptídeos/imunologia , Ligação Proteica , Proteínas Recombinantes , Proteína do Retinoblastoma/metabolismo , Linfócitos T/citologia
11.
Nat Biotechnol ; 18(9): 1001-5, 2000 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-10973224

RESUMO

Human cancers arise by a combination of discrete mutations and chromosomal alterations. Loss of heterozygosity (LOH) of chromosomal regions bearing mutated tumor suppressor genes is a key event in the evolution of epithelial and mesenchymal tumors. Global patterns of LOH can be understood through allelotyping of tumors with polymorphic genetic markers. Simple sequence length polymorphisms (SSLPs, or microsatellites) are reliable genetic markers for studying LOH, but only a modest number of SSLPs are used in LOH studies because the genotyping procedure is rather tedious. Here, we report the use of a highly parallel approach to genotype large numbers of single-nucleotide polymorphisms (SNPs) for LOH, in which samples are genotyped for nearly 1,500 loci by performing 24 polymerase chain reactions (PCR), pooling the resulting amplification products and hybridizing the mixture to a high-density oligonucleotide array. We characterize the results of LOH analyses on human small-cell lung cancer (SCLC) and control DNA samples by hybridization. We show that the patterns of LOH are consistent with those obtained by analysis with both SSLPs and comparative genomic hybridization (CGH), whereas amplifications rarely are detected by the SNP array. The results validate the use of SNP array hybridization for tumor studies.


Assuntos
Carcinoma de Células Pequenas/genética , Perda de Heterozigosidade , Neoplasias Pulmonares/genética , Análise de Sequência com Séries de Oligonucleotídeos/métodos , Polimorfismo Genético , Análise de Sequência de DNA/métodos , Alelos , Cromossomos Humanos Par 20 , Cromossomos Humanos Par 3 , Genótipo , Heterozigoto , Humanos , Hibridização de Ácido Nucleico/métodos , Ploidias , Polimorfismo de Nucleotídeo Único
13.
Oncogene ; 16(9): 1217-22, 1998 Mar 05.
Artigo em Inglês | MEDLINE | ID: mdl-9528864

RESUMO

The expression of telomerase, the enzyme that synthesizes telomeric DNA de novo, is suppressed in normal somatic human cells but is reactivated during tumorigenesis. This reactivation appears to arrest the normal loss of telomeric DNA incurred as human cells divide. Since continual loss of telomeric DNA is predicted to eventually limit cell proliferation, activation of telomerase in cancer cells may represent an important step in the acquisition of the cell immortalization which occurs during tumor progression. The telomerase holoenzyme is composed of both RNA and protein subunits. In humans, mRNA expression of hTERT (hEST2), the candidate telomerase catalytic subunit gene, appears to parallel the levels of telomerase enzyme activity, suggesting that induction of hTERT is necessary and perhaps sufficient for expression of telomerase activity in tumor cells. To test this model directly, we ectopically expressed an epitope-tagged version of hTERT in telomerase-negative cells and show that telomerase activity was induced to levels comparable to those seen in immortal telomerase-positive cells and that the expressed hTERT protein was physically associated with the cellular telomerase activity. We conclude that synthesis of the hTERT telomerase subunit represents the rate-limiting determinant of telomerase activity in these cells and that this protein, once expressed, becomes part of the functional telomerase holoenzyme.


Assuntos
Biossíntese de Proteínas , RNA , Telomerase/metabolismo , Linhagem Celular , Proteínas de Ligação a DNA , Células HL-60 , Humanos , Substâncias Macromoleculares , Proteínas/metabolismo , Proteínas Recombinantes/biossíntese , Proteínas Recombinantes/metabolismo , Telomerase/biossíntese , Transfecção , Células Tumorais Cultivadas
14.
J Clin Oncol ; 18(13): 2626-34, 2000 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-10893296

RESUMO

Shortening of the telomeric DNA at chromosome ends is postulated to limit the lifespan of human cells. In contrast, activation of telomerase, the enzyme that synthesizes telomeric DNA, is proposed to be an essential step in cancer cell immortalization and cancer progression. This review discusses the structure and function of telomeres and telomerase, the role of telomerase in cell immortalization, and the effects of telomerase inactivation on normal and cancer cells. Moreover, data on the experimental use of telomerase assays for cancer detection and diagnosis are reviewed. Finally, the review considers the evidence regarding whether telomerase inhibitors could be used to treat human cancers.


Assuntos
Neoplasias/fisiopatologia , Telomerase/fisiologia , Animais , Humanos , Neoplasias/diagnóstico , Neoplasias/genética , Neoplasias/terapia , Telomerase/genética
15.
AIDS ; 6(6): 557-61, 1992 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-1388877

RESUMO

OBJECTIVE: Difficulties involved in diagnosis and response to antimicrobial therapy are described in detail for two cases of biopsy-proven osteomyelitis caused by Mycobacterium haemophilum in AIDS patients. SETTING: Two large, private teaching hospitals in New York City, New York, USA. PATIENTS, PARTICIPANTS: A 31-year-old woman with previous diagnoses of candida esophagitis and peripheral neuropathy (patient 1), and a 37-year-old man with Kaposi's sarcoma (patient 2). INTERVENTIONS: One patient was treated with a combination of rifampin, ethambutol, clofazimine, and ciprofloxacin, while the other received rifampin, ciprofloxacin and doxycycline. Both patients also received a short course of intravenous amikacin. MAIN OUTCOME MEASURES: Disease activity was monitored clinically by observing resolution of skin ulcers, lymphadenopathy, and pain and swelling in areas affected by osteomyelitis. RESULTS: Both patients experienced complete resolution of signs and symptoms of M. haemophilum infection. Patient 1 was treated for 17 months and remains well after 10 months without therapy. Patient 2 shows no evidence of infection after 14 months of therapy. CONCLUSIONS: M. haemophilum infection must be considered in the differential diagnosis of osteomyelitis in AIDS patients, although specialized culture techniques are required to isolate and identify this pathogen. Excellent clinical response can be achieved with oral antimicrobial therapy.


Assuntos
Síndrome da Imunodeficiência Adquirida/complicações , Infecções por Mycobacterium/complicações , Infecções Oportunistas/complicações , Osteomielite/complicações , Adulto , Antibacterianos , Quimioterapia Combinada/uso terapêutico , Feminino , Humanos , Masculino , Infecções por Mycobacterium/diagnóstico , Infecções por Mycobacterium/tratamento farmacológico , Infecções Oportunistas/diagnóstico , Infecções Oportunistas/tratamento farmacológico , Osteomielite/tratamento farmacológico , Osteomielite/etiologia
17.
Int J Radiat Oncol Biol Phys ; 58(3): 698-704, 2004 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-14967423

RESUMO

PURPOSE: To evaluate efficacy and toxicity of the Duke University chemoirradiation regimen for locally advanced head-and-neck cancer in a regional community cancer center. METHODS AND MATERIALS: Between June 1998 and June 2002, 50 patients with Stage III or IVA squamous cell carcinoma of the head and neck were treated definitively with concurrent combined modality therapy (CMT). Patients received accelerated, hyperfractionated radiotherapy (AFRT), 1.2-1.25 Gy b.i.d., to a median prescribed dose of 70 Gy. Chemotherapy consisted of cisplatin 12 mg and fluorouracil 600 mg/m(2) daily for 5 consecutive days during Weeks 1 and 6, followed by two cycles after AFRT. Patients with N2-N3 neck disease (n = 21; 42%) were considered for neck dissection depending on their response to AFRT and chemotherapy. Twenty-nine patients with Stage III and IVA disease treated between 1991 and 1997 with definitive RT alone served as historical controls. RESULTS: Forty-nine patients (98%) in the CMT group completed the prescribed AFRT and 38 (76%) completed four cycles of chemotherapy. Three of 8 patients who underwent neck dissection had a pathologically complete response. The median follow-up for all patients was 23 months. The actuarial progression-free survival rate at 2 years was 75% for the CMT group vs. 40% (p <0.01) for the RT group. The overall survival rate was 80% and 43% (p <0.01), respectively, for the CMT and RT groups. Acute Radiation Therapy Oncology Group Grade 3 toxicities for the CMT group were mucosal (n = 50; 100%), skin (n = 9; 18%), and hematologic (n = 3; 6%). Late Grade 3-4 toxicities consisted of pharyngeal stricture (n = 7; 14%), laryngeal chondritis (n = 3; 6%), osteoradionecrosis (n = 2; 4%), and peripheral neuropathy (n = 1; 2%). CONCLUSION: This aggressive regimen of AFRT with concurrent cisplatin and fluorouracil with or without neck dissection is feasible in the community setting for patients with Stage III and IVA head-and-neck cancer. Early results indicated excellent survival, albeit with universal acute mucosal, and considerable, although acceptable, late toxicity.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Carcinoma de Células Escamosas/tratamento farmacológico , Carcinoma de Células Escamosas/radioterapia , Neoplasias de Cabeça e Pescoço/tratamento farmacológico , Neoplasias de Cabeça e Pescoço/radioterapia , Carcinoma de Células Escamosas/patologia , Cisplatino/administração & dosagem , Terapia Combinada , Fracionamento da Dose de Radiação , Feminino , Fluoruracila/administração & dosagem , Neoplasias de Cabeça e Pescoço/patologia , Humanos , Masculino , Pessoa de Meia-Idade , Estadiamento de Neoplasias
18.
Mayo Clin Proc ; 69(12): 1159-62, 1994 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-7967777

RESUMO

Aplastic anemia developed in a black woman who was receiving dapsone therapy for bullous systemic lupus erythematosus. Aplastic anemia is an uncommon adverse hematologic effect in patients treated with dapsone, the pathogenesis of which remains unknown. To our knowledge, dapsone-induced aplastic anemia has been previously reported in only four patients; the characteristics of their cases are described herein. Conservative monitoring of hematologic variables may alert clinicians to the early stages of this rare drug reaction.


Assuntos
Anemia Aplástica/induzido quimicamente , Dapsona/efeitos adversos , Lúpus Eritematoso Sistêmico/tratamento farmacológico , Dermatopatias Vesiculobolhosas/tratamento farmacológico , Adolescente , Adulto , Dapsona/uso terapêutico , Feminino , Humanos , Masculino , Pessoa de Meia-Idade
19.
Toxicol Lett ; 102-103: 41-5, 1998 Dec 28.
Artigo em Inglês | MEDLINE | ID: mdl-10022230

RESUMO

Activity of telomerase, the enzyme that synthesizes the telomere ends of linear eukaryotic chromosomes, is repressed in most normal human somatic cells but induced in most human cancers. Normal human cells that lack telomerase activity progressively lose telomere sequences. In contrast, most immortalized cell lines and malignant human tumors appear to maintain constant telomere length via telomerase activity. Telomerase is composed of at least two subunits, an RNA subunit that templates telomere synthesis, and a catalytic protein subunit. The gene encoding the catalytic protein subunit of telomerase has recently been identified, first in yeast and ciliates and then in humans. This catalytic subunit belongs to the reverse transcriptase family. Studies of telomerase subunits further define a role for telomerase in the control of mammalian cell lifespan. The expression of the human telomerase catalytic subunit gene, hTERT, is induced in immortalized cells and primary tumors. When hTERT is ectopically expressed in hitherto telomerase-negative cells, telomerase enzyme activity appears, and an extended lifespan has been observed in some cells. In contrast, disruption of the mouse telomerase RNA subunit gene, mTERC, results in a delayed failure of cell proliferation. Telomerase activity therefore appears to be necessary for the prolonged survival of mammalian cells.


Assuntos
Sobrevivência Celular , RNA , Telomerase/fisiologia , Animais , Domínio Catalítico , Proteínas de Ligação a DNA , Ativação Enzimática , Humanos , Camundongos , Proteínas/genética
20.
J Natl Med Assoc ; 78(5): 409-19, 1986 May.
Artigo em Inglês | MEDLINE | ID: mdl-3712479

RESUMO

Birth defects increase the risk of speech, language, and hearing disorders in childhood. The prevalence of particular congenital anomalies varies from one racial and ethnic group to another. Some conditions such as the hemoglobinopathies, polydactyly, and external ear malformations are more common among black people. Other birth defects are rarer among black children, notably cleft lip and palate, neural tube defects, and phenylketonuria. The more common defects of Down's syndrome, neurofibromatosis, and cerebral palsy appear to occur in equal frequency in black and white Americans.Speech-language pathologists, audiologists, and other health professionals who work with black children with birth defects must be familiar with the special problems and the positive features reflected in this population. Difficulties in obtaining adequate medical care, poor health and nutrition, and inadequate financial support are problems plaguing the poor. However, the shared responsibility assumed by the church, the community, and the extended family often results in positive acceptance of the handicapped child. Many families rely on folk medicine whose remedies can often be combined with traditional therapies for the ultimate benefit of the patient.Health professionals must assume a managerial role to ensure that services reach the child with syndrome-related speech, language, and hearing problems.


Assuntos
População Negra , Anormalidades Congênitas/diagnóstico , Transtornos da Audição/diagnóstico , Transtornos do Desenvolvimento da Linguagem/diagnóstico , Distúrbios da Fala/diagnóstico , Criança , Humanos , Síndrome
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