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1.
World J Surg ; 2024 Apr 22.
Artigo em Inglês | MEDLINE | ID: mdl-38647223

RESUMO

BACKGROUND: Gastrointestinal Stromal Tumors (GISTs) are the most common mesenchymal tumors of the GI tract. SEER is an extensive cancer database which proves useful in analyzing population trends. This analysis investigated GIST outcomes between geriatric & non-geriatric patients. METHODS: SEER*STAT 8.4.0.1 was used to extract relevant GIST data from 2000 to 2019. Geriatric age was defined as ≥70 years. Variables included age, sex, surgery, cancer-specific death, and overall survival. Statistical tests included univariate analysis using KM survival estimate (95% confidence interval) to calculate 5-year survival (5YS). Log-Rank tests determined statistical significance. Multivariable Cox's PH regression estimated the geriatric hazard death ratio adjusted for sex, stage, and surgery. RESULTS: The number of patients included was 13,579, yielding overall 5YS of 68.6% (95% CI 67.7-69.5). Cancer-specific death was 39.11% in 2000 & 3.33% in 2019. Non-geriatric & geriatric patient data yielded 5YS of 77.4% (76.4%-78.3%) and 53.3% (51.7%-54.8%) respectively (p < 0.0001). For no surgery/surgery, younger patient data yielded 5YS of 48.7% (45.8%-51.4%) and 83.7% (82.7%-84.7%) respectively (p < 0.0001); geriatric data yielded 5YS of 29.3% (26.5%-32.1%) and 62.8% (60.8%-64.6%) respectively (p < 0.0001). Multivariable analysis yielded a geriatric hazard death of 2.56 (2.42-2.70) (p < 0.0001). CONCLUSIONS: Cancer-specific death decreased since 2000, indicating an improvement in survival & treatment methods. Observed lower survival rates overall in the geriatric group. Surgery appeared to enhance survival rates in both groups, suggesting that surgery is an important factor in GIST survival regardless of age. Large prospective studies will help define clinical management for geriatric patients.

2.
Cancer J ; 30(2): 92-101, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38527262

RESUMO

ABSTRACT: Uveal melanoma (UM), arising from intraocular melanocytes, poses a complex clinical challenge with a substantial risk of distant metastasis, often to the liver. Molecular profiling, encompassing genetic, cytogenetic, gene expression, and immunological subsets, plays a pivotal role in determining prognoses. The evolving landscape includes promising systemic treatments, such as tebentafusp, a novel immune-modulating bispecific fusion protein, and targeted therapies. Combined regional and systemic approaches, including immune checkpoint inhibitors and innovative liver-directed therapy, are also under investigation. Although recent progress has improved outcomes, ongoing research aims to address the unique challenges of UM and develop effective therapies, particularly for HLA-A*02:01-negative patients who represent a significant unmet medical need. This review comprehensively discusses the molecular characteristics of UM, risk stratification methods, and the current and future spectrum of regional and systemic therapeutic modalities.


Assuntos
Melanoma , Neoplasias Uveais , Humanos , Melanoma/terapia , Melanoma/tratamento farmacológico , Neoplasias Uveais/diagnóstico , Neoplasias Uveais/genética , Neoplasias Uveais/terapia , Prognóstico
3.
Nat Med ; 30(2): 531-542, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38195752

RESUMO

Pancreatic and colorectal cancers are often KRAS mutated and are incurable when tumor DNA or protein persists or recurs after curative intent therapy. Cancer vaccine ELI-002 2P enhances lymph node delivery and immune response using amphiphile (Amph) modification of G12D and G12R mutant KRAS (mKRAS) peptides (Amph-Peptides-2P) together with CpG oligonucleotide adjuvant (Amph-CpG-7909). We treated 25 patients (20 pancreatic and five colorectal) who were positive for minimal residual mKRAS disease (ctDNA and/or serum tumor antigen) after locoregional treatment in a phase 1 study of fixed-dose Amph-Peptides-2P and ascending-dose Amph-CpG-7909; study enrollment is complete with patient follow-up ongoing. Primary endpoints included safety and recommended phase 2 dose (RP2D). The secondary endpoint was tumor biomarker response (longitudinal ctDNA or tumor antigen), with exploratory endpoints including immunogenicity and relapse-free survival (RFS). No dose-limiting toxicities were observed, and the RP2D was 10.0 mg of Amph-CpG-7909. Direct ex vivo mKRAS-specific T cell responses were observed in 21 of 25 patients (84%; 59% both CD4+ and CD8+); tumor biomarker responses were observed in 21 of 25 patients (84%); biomarker clearance was observed in six of 25 patients (24%; three pancreatic and three colorectal); and the median RFS was 16.33 months. Efficacy correlated with T cell responses above or below the median fold increase over baseline (12.75-fold): median tumor biomarker reduction was -76.0% versus -10.2% (P < 0.0014), and the median RFS was not reached versus 4.01 months (hazard ratio = 0.14; P = 0.0167). ELI-002 2P was safe and induced considerable T cell responses in patients with immunotherapy-recalcitrant KRAS-mutated tumors. ClinicalTrials.gov identifier: NCT04853017 .


Assuntos
Neoplasias Colorretais , Vacinas , Humanos , Proteínas Proto-Oncogênicas p21(ras)/genética , Recidiva Local de Neoplasia/patologia , Biomarcadores Tumorais/genética , Vacinas/uso terapêutico , Neoplasias Colorretais/tratamento farmacológico , Neoplasias Colorretais/genética , Peptídeos , Antígenos de Neoplasias/uso terapêutico
4.
J Clin Oncol ; 41(23): 3895-3898, 2023 Aug 10.
Artigo em Inglês | MEDLINE | ID: mdl-37307516
5.
N Engl J Med ; 388(9): 813-823, 2023 Mar 02.
Artigo em Inglês | MEDLINE | ID: mdl-36856617

RESUMO

BACKGROUND: Whether pembrolizumab given both before surgery (neoadjuvant therapy) and after surgery (adjuvant therapy), as compared with pembrolizumab given as adjuvant therapy alone, would increase event-free survival among patients with resectable stage III or IV melanoma is unknown. METHODS: In a phase 2 trial, we randomly assigned patients with clinically detectable, measurable stage IIIB to IVC melanoma that was amenable to surgical resection to three doses of neoadjuvant pembrolizumab, surgery, and 15 doses of adjuvant pembrolizumab (neoadjuvant-adjuvant group) or to surgery followed by pembrolizumab (200 mg intravenously every 3 weeks for a total of 18 doses) for approximately 1 year or until disease recurred or unacceptable toxic effects developed (adjuvant-only group). The primary end point was event-free survival in the intention-to-treat population. Events were defined as disease progression or toxic effects that precluded surgery; the inability to resect all gross disease; disease progression, surgical complications, or toxic effects of treatment that precluded the initiation of adjuvant therapy within 84 days after surgery; recurrence of melanoma after surgery; or death from any cause. Safety was also evaluated. RESULTS: At a median follow-up of 14.7 months, the neoadjuvant-adjuvant group (154 patients) had significantly longer event-free survival than the adjuvant-only group (159 patients) (P = 0.004 by the log-rank test). In a landmark analysis, event-free survival at 2 years was 72% (95% confidence interval [CI], 64 to 80) in the neoadjuvant-adjuvant group and 49% (95% CI, 41 to 59) in the adjuvant-only group. The percentage of patients with treatment-related adverse events of grades 3 or higher during therapy was 12% in the neoadjuvant-adjuvant group and 14% in the adjuvant-only group. CONCLUSIONS: Among patients with resectable stage III or IV melanoma, event-free survival was significantly longer among those who received pembrolizumab both before and after surgery than among those who received adjuvant pembrolizumab alone. No new toxic effects were identified. (Funded by the National Cancer Institute and Merck Sharp and Dohme; S1801 ClinicalTrials.gov number, NCT03698019.).


Assuntos
Antineoplásicos Imunológicos , Melanoma , Terapia Neoadjuvante , Neoplasias Cutâneas , Humanos , Adjuvantes Imunológicos , Progressão da Doença , Melanoma/tratamento farmacológico , Melanoma/patologia , Melanoma/cirurgia , Neoplasias Cutâneas/tratamento farmacológico , Neoplasias Cutâneas/patologia , Neoplasias Cutâneas/cirurgia , Antineoplásicos Imunológicos/administração & dosagem , Antineoplásicos Imunológicos/efeitos adversos , Antineoplásicos Imunológicos/uso terapêutico , Quimioterapia Adjuvante
6.
Oncoimmunology ; 10(1): 1898105, 2021 03 26.
Artigo em Inglês | MEDLINE | ID: mdl-33796406

RESUMO

Ipilimumab (IPI) can enhance immunity to the cancer-testis antigen NY-ESO-1. A clinical trial was designed to assess safety, immunogenicity, and clinical responses with IPI + NY-ESO-1 vaccines and effects on the tumor microenvironment (TME). Patients with measurable NY-ESO-1+ tumors were enrolled among three arms: A) IPI + NY-ESO-1 protein + poly-ICLC (pICLC) + incomplete Freund's adjuvant (IFA); B) IPI + NY-ESO-1 overlapping long peptides (OLP) + pICLC + IFA; and C) IPI + NY-ESO-1 OLP + pICLC. Clinical responses were assessed by irRC. T cell and Ab responses were assessed by ex vivo IFN-gamma ELIspot and ELISA. Tumor biopsies pre- and post-treatment were evaluated for immune infiltrates. Eight patients were enrolled: 5, 2, and 1 in Arms A-C, respectively. There were no DLTs. Best clinical responses were SD (4) and PD (4). T-cell and antibody (Ab) responses to NY-ESO-1 were detected in 6 (75%) and 7 (88%) patients, respectively, and were associated with SD. The breadth of Ab responses was greater for patients with SD than PD (p = .036). For five patients evaluable in the TME, treatment was associated with increases in proliferating (Ki67+) CD8+ T cells and decreases in RORγt+ CD4+ T cells. T cell densities increased for those with SD. Detection of T cell responses to NY-ESO-1 ex vivo in most patients suggests that IPI may have enhanced those responses. Proliferating intratumoral CD8+ T cells increased after vaccination plus IPI suggesting favorable impact of IPI plus NY-ESO-1 vaccines on the TME. List of Abbreviations: Ab = antibody; CTCAE = NCI Common Terminology Criteria for Adverse Events; DHFR/DHRP = dihydrofolate reductase; DLT = Dose-limiting toxicity; ELISA = enzyme-linked immunosorbent assay; IFA = incomplete Freund's adjuvant (Montanide ISA-51); IFNγ = Interferon gamma; IPI = Ipilimumab; irRC = immune-related response criteria; mIFH = multispectral immunofluorescence histology; OLP = NY-ESO-1 overlapping long peptides; PBMC = peripheral blood mononuclear cells; PD = Progressive disease; pICLC = poly-ICLC (Hiltonol), a TLR3/MDA-5 agonist; RLT = Regimen-limiting Toxicity; ROI = regions of interest; RT = room temperature; SAE = serious adverse event; SD = stable disease; TEAE = treatment-emergent adverse events; TLR = toll-like receptor; TME = tumor microenvironment; TRAE = treatment-related adverse events.


Assuntos
Vacinas Anticâncer , Melanoma , Antígenos de Neoplasias , Linfócitos T CD4-Positivos , Linfócitos T CD8-Positivos , Vacinas Anticâncer/efeitos adversos , Humanos , Ipilimumab/uso terapêutico , Leucócitos Mononucleares , Masculino , Melanoma/tratamento farmacológico , Microambiente Tumoral
7.
Kidney Int ; 100(1): 196-205, 2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-33359528

RESUMO

Immune checkpoint inhibitors (ICIs) are widely used for various malignancies. However, their safety and efficacy in patients with a kidney transplant have not been defined. To delineate this, we conducted a multicenter retrospective study of 69 patients with a kidney transplant receiving ICIs between January 2010 and May 2020. For safety, we assessed the incidence, timing, and risk factors of acute graft rejection. For efficacy, objective response rate and overall survival were assessed in cutaneous squamous cell carcinoma and melanoma, the most common cancers in our cohort, and compared with stage-matched 23 patients with squamous cell carcinoma and 14 with melanoma with a kidney transplant not receiving ICIs. Following ICI treatment, 29 out of 69 (42%) patients developed acute rejection, 19 of whom lost their allograft, compared with an acute rejection rate of 5.4% in the non-ICI cohort. Median time from ICI initiation to rejection was 24 days. Factors associated with a lower risk of rejection were mTOR inhibitor use (odds ratio 0.26; 95% confidence interval, 0.09-0.72) and triple-agent immunosuppression (0.67, 0.48-0.92). The objective response ratio was 36.4% and 40% in the squamous cell carcinoma and melanoma subgroups, respectively. In the squamous cell carcinoma subgroup, overall survival was significantly longer in patients treated with ICIs (median overall survival 19.8 months vs. 10.6 months), whereas in the melanoma subgroup, overall survival did not differ between groups. Thus, ICIs were associated with a high risk of rejection in patients with kidney transplants but may lead to improved cancer outcomes. Prospective studies are needed to determine optimal immunosuppression strategies to improve patient outcomes.


Assuntos
Carcinoma de Células Escamosas , Transplante de Rim , Neoplasias Cutâneas , Carcinoma de Células Escamosas/tratamento farmacológico , Humanos , Inibidores de Checkpoint Imunológico , Transplante de Rim/efeitos adversos , Estudos Prospectivos , Estudos Retrospectivos , Neoplasias Cutâneas/tratamento farmacológico
8.
Lung Cancer Manag ; 9(2): LMT31, 2020 Apr 24.
Artigo em Inglês | MEDLINE | ID: mdl-32346405

RESUMO

BACKGROUND: Checkpoint inhibitors are integral to non-small-cell lung cancer treatment. Existing data suggests that nutritional status may play a role in antitumor immunity. MATERIALS & METHODS: This retrospective study of 106 non-small-cell lung cancer patients who started checkpoint inhibitors between 2014 and 2017 at our institution assessed relationship of nutritional parameters to overall survival (OS) and progression-free survival. RESULTS: Mean age was 68.7 ± 9.2 years and 59.4% patients were male. On multivariate analysis for OS, hypoalbuminemia and significant weight loss were prognostic at p-values of 0.0005 and 0.0052, respectively. We noted a parabolic association between age and OS (p = 0.026, 0.0025). CONCLUSION: In our study, some malnutrition parameters were associated with decreased OS. U-shape relationship between age and OS noted here warrants further evaluation.

9.
JAMA Oncol ; 3(11): 1546-1553, 2017 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-28617917

RESUMO

IMPORTANCE: Small-bowel adenocarcinomas (SBAs) are rare cancers with a significantly lower incidence, later stage at diagnosis, and worse overall survival than other intestinal-derived cancers. To date, comprehensive genomic analysis of SBA is lacking. OBJECTIVE: To perform in-depth genomic characterization of a large series of SBAs and other gastrointestinal tumors to draw comparisons and identify potentially clinically actionable alterations. DESIGN, SETTING, AND PARTICIPANTS: Prospective analysis was performed of clinical samples from patients with SBA (n = 317), colorectal cancer (n = 6353), and gastric carcinoma (n = 889) collected between August 24, 2012, and February 3, 2016, using hybrid-capture-based genomic profiling, at the request of the individual treating physicians in the course of clinical care for the purpose of making therapy decisions. RESULTS: Of the 7559 patients included in analysis, 4138 (54.7%) were male; the median age was 56 (range, 12-101) years. The frequency of genomic alterations seen in SBA demonstrated distinct differences in comparison with either colorectal cancer (APC: 26.8% [85 of 317] vs 75.9% [4823 of 6353], P < .001; and CDKN2A: 14.5% [46 of 317] vs 2.6% [165 of 6353], P < .001) or gastric carcinoma (KRAS: 53.6% [170 of 317] vs 14.2% [126 of 889], P < .001; APC: 26.8% [85 of 317] vs 7.8% [69 of 889], P < .001; and SMAD4: 17.4% [55 of 317] vs 5.2% [46 of 889], P < .001). BRAF was mutated in 7.6% (484 of 6353) of colorectal cancer and 9.1% (29 of 317) of SBA samples, but V600E mutations were much less common in SBA, representing only 10.3% (3 of 29) of BRAF-mutated cases. The ERBB2/HER2 point mutations (8.2% [26 of 317]), microsatellite instability (7.6% [13 of 170]), and high tumor mutational burden (9.5% [30 of 317]) were all enriched in SBA. Significant differences were noted in the molecular profile of unspecified SBA compared with duodenal adenocarcinoma, as well as in inflammatory bowel disease-associated SBAs. Targetable alterations in several additional genes, including PIK3CA and MEK1, and receptor tyrosine kinase fusions, were also identified in all 3 series. CONCLUSIONS AND RELEVANCE: This study presents to our knowledge the first large-scale genomic comparison of SBA with colorectal cancer and gastric carcinoma. The distinct genomic differences establish SBA as a molecularly unique intestinal cancer. In addition, genomic profiling can identify potentially targetable genomic alterations in the majority of SBA cases (91%), and the higher incidence of microsatellite instability and tumor mutational burden in SBA suggests a potential role for immunotherapy.


Assuntos
Adenocarcinoma/genética , Biomarcadores Tumorais/genética , Perfilação da Expressão Gênica/métodos , Neoplasias Intestinais/genética , Intestino Delgado , Transcriptoma , Adenocarcinoma/patologia , Adenocarcinoma/terapia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Criança , Neoplasias Colorretais/genética , Neoplasias Colorretais/patologia , Neoplasias Duodenais/genética , Neoplasias Duodenais/patologia , Neoplasias Duodenais/terapia , Feminino , Predisposição Genética para Doença , Humanos , Neoplasias Intestinais/patologia , Neoplasias Intestinais/terapia , Intestino Delgado/patologia , Masculino , Instabilidade de Microssatélites , Pessoa de Meia-Idade , Mutação , Fenótipo , Medicina de Precisão , Valor Preditivo dos Testes , Estudos Prospectivos , Neoplasias Gástricas/genética , Neoplasias Gástricas/patologia , Adulto Jovem
10.
Cancer ; 122(15): 2379-88, 2016 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-27171984

RESUMO

BACKGROUND: Outcomes among older patients with acute lymphoblastic leukemia remain poor. This study sought to determine the efficacy of an intensified, multi-agent approach derived from a Dana-Farber consortium trial in younger adults for patients older than 50 years (trial identifier NCT00973752). METHODS: The primary endpoint was overall survival (OS) at 1 year. Patients received induction chemotherapy with vincristine, prednisone, doxorubicin, and pegylated asparaginase. Imatinib was incorporated for Philadelphia chromosome-positive disease. After induction, the first consolidation incorporated clofarabine. Patients in remission could proceed to allogeneic hematopoietic cell transplantation (HCT) after induction and consolidation I. Those not receiving HCT went on to receive central nervous system, consolidation II, and continuation phases of treatment. RESULTS: Thirty patients were enrolled: 19 achieved a complete remission (CR) after induction and 1 achieved CR after consolidation I for a CR rate of 67%. Sixteen patients underwent HCT. The proportion surviving at 1 year was 63%, and this met the primary endpoint. The 2-year OS rate was 52% (n = 30), and the 2-year disease-free survival rate was 52% for patients achieving CR (n = 20). There was no survival advantage among those undergoing HCT. Therapy-related hyperbilirubinemia prompted adjustments and limitations to asparaginase dosing. CONCLUSIONS: Intensified chemotherapy can result in improved outcomes in comparison with historical data. Additional studies of similarly intensive regimens are warranted in this population. Cancer 2016;122:2379-2388. © 2016 American Cancer Society.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Transplante de Células-Tronco Hematopoéticas , Leucemia-Linfoma Linfoblástico de Células Precursoras/terapia , Fatores Etários , Idoso , Idoso de 80 Anos ou mais , Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Biomarcadores , Terapia Combinada , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Leucemia-Linfoma Linfoblástico de Células Precursoras/diagnóstico , Leucemia-Linfoma Linfoblástico de Células Precursoras/mortalidade , Indução de Remissão , Análise de Sobrevida , Transplante Homólogo
11.
Clin Cancer Res ; 22(12): 2848-54, 2016 06 15.
Artigo em Inglês | MEDLINE | ID: mdl-26813359

RESUMO

PURPOSE: This phase Ib study evaluated the safety and tolerability of PEGylated human recombinant hyaluronidase (PEGPH20) in combination with gemcitabine (Gem), and established a phase II dose for patients with untreated stage IV metastatic pancreatic ductal adenocarcinoma (PDA). Objective response rate and treatment efficacy using biomarker and imaging measurements were also evaluated. EXPERIMENTAL DESIGN: Patients received escalating intravenous doses of PEGPH20 in combination with Gem using a standard 3+3 dose-escalation design. In cycle 1 (8 weeks), PEGPH20 was administrated twice weekly for 4 weeks, then once weekly for 3 weeks; Gem was administrated once weekly for 7 weeks, followed by 1 week off treatment. In each subsequent 4-week cycle, PEGPH20 and Gem were administered once weekly for 3 weeks, followed by 1 week off. Dexamethasone (8 mg) was given pre- and post-PEGPH20 administration. Several safety parameters were evaluated. RESULTS: Twenty-eight patients were enrolled and received PEGPH20 at 1.0 (n = 4), 1.6 (n = 4), or 3.0 µg/kg (n = 20), respectively. The most common PEGPH20-related adverse events were musculoskeletal and extremity pain, peripheral edema, and fatigue. The incidence of thromboembolic events was 29%. Median progression-free survival (PFS) and overall survival (OS) rates were 5.0 and 6.6 months, respectively. In 17 patients evaluated for pretreatment tissue hyaluronan (HA) levels, median PFS and OS rates were 7.2 and 13.0 months for "high"-HA patients (n = 6), and 3.5 and 5.7 months for "low"-HA patients (n = 11), respectively. CONCLUSIONS: PEGPH20 in combination with Gem was well tolerated and may have therapeutic benefit in patients with advanced PDA, especially in those with high HA tumors. Clin Cancer Res; 22(12); 2848-54. ©2016 AACR.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Carcinoma Ductal Pancreático/tratamento farmacológico , Desoxicitidina/análogos & derivados , Hialuronoglucosaminidase/uso terapêutico , Neoplasias Pancreáticas/tratamento farmacológico , Adulto , Idoso , Idoso de 80 Anos ou mais , Carcinoma Ductal Pancreático/patologia , Desoxicitidina/uso terapêutico , Dexametasona/uso terapêutico , Intervalo Livre de Doença , Feminino , Humanos , Hialuronoglucosaminidase/efeitos adversos , Hialuronoglucosaminidase/química , Hialuronoglucosaminidase/genética , Neoplasias Hepáticas/secundário , Neoplasias Pulmonares/secundário , Metástase Linfática/patologia , Masculino , Pessoa de Meia-Idade , Pâncreas/patologia , Neoplasias Pancreáticas/patologia , Polietilenoglicóis/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/uso terapêutico , Federação Russa , Resultado do Tratamento , Estados Unidos , Gencitabina
12.
J Oncol Pharm Pract ; 22(2): 357-60, 2016 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-25591868

RESUMO

Pomalidomide is an analog of thalidomide with immunomodulatory, anti-angiogenic, and anti-neoplastic activity indicated for the treatment of multiple myeloma refractory to at least two prior therapies. The incidence for renal failure was <5% in a single phase II study of pomalidomide and dexamethasone in patients with multiple myeloma that failed both lenalidomide and bortezomib therapy. We report a case suggesting crystal nephropathy as the mechanism for acute kidney injury in pomalidomide and fluoroquinolone use.


Assuntos
Injúria Renal Aguda/induzido quimicamente , Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Levofloxacino/efeitos adversos , Talidomida/análogos & derivados , Injúria Renal Aguda/diagnóstico , Idoso , Protocolos de Quimioterapia Combinada Antineoplásica/administração & dosagem , Feminino , Humanos , Levofloxacino/administração & dosagem , Mieloma Múltiplo/diagnóstico , Mieloma Múltiplo/tratamento farmacológico , Talidomida/administração & dosagem , Talidomida/efeitos adversos
14.
Blood ; 101(8): 3021-8, 2003 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-12515716

RESUMO

Human blood platelets are anucleate cells whose response to extracellular stimuli results in actin cytoskeleton rearrangements, thereby providing the critical initial step in the regulation of hemostasis. The serine protease alpha-thrombin, known to activate platelets by cleavage of a family of protease-activated receptors (PARs), is the most potent physiologic activator of human platelets, though downstream effector proteins uniquely linked to platelet cytoskeletal actin polymerization remain largely uncharacterized. The gene encoding the putative rac1/cdc42 effector protein IQGAP2 was identified within the PAR gene cluster at 5q13, flanked telomeric by PAR1 and encompassing PAR3. Immunofluorescence microscopy demonstrated IQGAP2 expression in filopodial extensions of activated platelets and colocalized with F-actin in lamellipodia and filopodia of IQGAP2-transfected COS1 cells. Platelet activation by alpha-thrombin, but not saturating concentrations of fibrillar collagen or adenosine 5'-diphosphate, uniquely assemble an IQGAP2/arp2/3-actin cytoplasmic complex, an association regulated by guanosine triphosphate rac1 ([GTP]rac1) but not by [GTP]cdc42. Likewise, only thrombin-activated platelets resulted in rapid translocation of IQGAP2 to the platelet cytoskeleton. These observations identify a physiologic scaffolding function for IQGAP2 and establish the presence of a functional genomic unit in humans uniquely evolved to regulate thrombin-induced platelet cytoskeletal actin reorganization.


Assuntos
Plaquetas/ultraestrutura , Proteínas de Transporte/fisiologia , Cromossomos Humanos Par 5/genética , Citoesqueleto/ultraestrutura , Ativação Plaquetária/efeitos dos fármacos , Trombina/farmacologia , Proteínas Ativadoras de ras GTPase , Proteína 2 Relacionada a Actina , Proteína 3 Relacionada a Actina , Actinas/metabolismo , Difosfato de Adenosina/farmacologia , Adulto , Animais , Plaquetas/efeitos dos fármacos , Células COS/química , Células COS/ultraestrutura , Proteínas de Transporte/genética , Chlorocebus aethiops , Colágeno/farmacologia , Proteínas do Citoesqueleto/metabolismo , Citoesqueleto/efeitos dos fármacos , Guanosina Trifosfato/metabolismo , Humanos , Substâncias Macromoleculares , Microscopia de Fluorescência , Mapeamento Físico do Cromossomo , Pseudópodes/química , Transfecção , Proteína cdc42 de Ligação ao GTP/fisiologia , Proteínas rac1 de Ligação ao GTP/fisiologia
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