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1.
Future Oncol ; : 1-13, 2024 May 02.
Artigo em Inglês | MEDLINE | ID: mdl-38695479

RESUMO

Treatment options for patients with advanced or metastatic esophageal squamous cell carcinoma (ESCC) are improving. Current guidelines recommend first-line pembrolizumab plus chemotherapy for patients with unresectable or metastatic ESCC, which has led to improvements in survival outcomes. Antiangiogenic therapy combined with immune checkpoint inhibitors can act synergistically to convert the immunosuppressive tumor microenvironment to an immune supportive microenvironment, thus enhancing antitumor immune responses. In preclinical models, the antiangiogenic agent lenvatinib combined with an anti-PD-1 agent showed synergistic antitumor activity. We describe the design and rationale for the randomized, open-label, phase III LEAP-014 study of lenvatinib in combination with pembrolizumab plus chemotherapy in patients with advanced or metastatic ESCC. Overall survival and progression-free survival are the dual primary end points.Clinical Trial Registration: NCT04949256 (ClinicalTrials.gov).


[Box: see text].

2.
J Surg Oncol ; 119(1): 64-70, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30481370

RESUMO

BACKGROUND: The three-delays model describes delays in seeking, reaching, and receiving care for vulnerable populations needing treatment. The dominant delay for patients with gastric adenocarcinoma (GAC) is unknown. We aimed to define patients with GAC who reached and received care at our regional safety-net hospital (Grady Memorial Hospital [GMH]) and our neighboring quaternary referral hospital (Emory University Hospital [EUH]). METHODS: Clinicopathologic data from National Cancer Database (NCDB) participating academic centers were compared with GMH from 2004 to 2014. Outcomes of patients undergoing surgery at GMH were compared to those at EUH. RESULTS: At presentation, compared to NCDB centers (n = 69 662), GMH patients (n = 154) were more often black (85.1 vs 17.2%; P < 0.001), uninsured (30.5 vs 4.7%; P < 0.001), have stage IV disease (43.5 vs 30.1%; P = 0.017), and received no treatment (40.3 vs 18.4%; P < 0.001). When only comparing patients who underwent curative-intent resection at GMH (n = 23) to EUH (n = 137), median overall survival was similar between both groups (GMH: median not reached; EUH: 59.8 mos; P = 0.785). CONCLUSION: Although vulnerable patients with GAC within a safety-net hospital present with later stages of the disease, those who received surgery have acceptable outcomes. Thus, efforts should be made to overcome barriers in seeking care.


Assuntos
Adenocarcinoma/cirurgia , Acessibilidade aos Serviços de Saúde/estatística & dados numéricos , Hospitais/estatística & dados numéricos , Padrões de Prática Médica/normas , Encaminhamento e Consulta , Provedores de Redes de Segurança/normas , Neoplasias Gástricas/cirurgia , Adenocarcinoma/epidemiologia , Adenocarcinoma/patologia , Feminino , Seguimentos , Disparidades em Assistência à Saúde , Humanos , Masculino , Pessoa de Meia-Idade , Prognóstico , Qualidade da Assistência à Saúde , Estudos Retrospectivos , Neoplasias Gástricas/epidemiologia , Neoplasias Gástricas/patologia , Taxa de Sobrevida , Estados Unidos/epidemiologia
3.
Ann Surg Oncol ; 22(7): 2295-301, 2015 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-25786743

RESUMO

BACKGROUND: Clinicians may order Octreoscan or positron emission tomography (PET) scan for staging patients with neuroendocrine tumors (NETs). (111)In-Octreoscan (Octreoscan) identifies tumors by radiolabeled targeting of somatostatin receptors, while 18F-fluorodeoxyglucose-positron emission tomography ((18)FDG-PET) measures differential tissue glucose transport. We assessed the sensitivity of both nuclear imaging modalities with pathologic correlation to define the best initial choice for NET staging after standard cross-sectional imaging. METHODS: We identified all patients diagnosed with NETs of gastrointestinal or pancreatic origin who underwent nuclear imaging staging by Octreoscan and/or PET from 2000 to 2013. Imaging results were correlated with tumor differentiation and grade of pathology specimens. RESULTS: Imaging and pathology results were identified for 153 patients. Of these, 131 underwent Octreoscan, 43 underwent PET, and 21 patients had both performed. Overall sensitivity of Octreoscan and PET for NET detection was similar (77 vs. 72 %; p = not significant). For well-differentiated NETs, Octreoscan (n = 124) demonstrated sensitivity of 80 vs. 60 % (p = 0.28) for PET (n = 30). For poorly-differentiated NETs, Octreoscan (n = 7) proved significantly less sensitive than PET (n = 13) (57 vs. 100 %; p = 0.02). The sensitivity of Octreoscan versus PET varied similarly when analyzed by WHO tumor grade: Grade 1 (79 vs. 52 %; p = 0.16), Grade 2 (85 vs. 86 %; p = not significant), and Grade 3 (57 vs. 100 %; p = 0.02). CONCLUSIONS: Tumor differentiation can be used to guide selection of nuclear imaging modalities for staging gastrointestinal and pancreatic NETs. Octreoscan appears more sensitive than (18)FDG-PET for well-differentiated NETs, whereas (18)FDG-PET demonstrates superior sensitivity for poorly-differentiated NETs.


Assuntos
Fluordesoxiglucose F18/farmacocinética , Radioisótopos de Índio/farmacocinética , Tumores Neuroendócrinos/diagnóstico por imagem , Tomografia por Emissão de Pósitrons/métodos , Compostos Radiofarmacêuticos/farmacocinética , Somatostatina/análogos & derivados , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Seguimentos , Humanos , Processamento de Imagem Assistida por Computador , Masculino , Pessoa de Meia-Idade , Gradação de Tumores , Tumores Neuroendócrinos/mortalidade , Tumores Neuroendócrinos/patologia , Prognóstico , Estudos Prospectivos , Sensibilidade e Especificidade , Somatostatina/farmacocinética , Taxa de Sobrevida , Tomografia Computadorizada por Raios X , Adulto Jovem
4.
J Clin Oncol ; 41(1): 75-85, 2023 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-35867951

RESUMO

PURPOSE: Effective treatments are needed for melanoma that progresses on inhibitors of programmed cell death protein-1 (PD-1) or its ligand (PD-L1). We conducted the phase II LEAP-004 study to evaluate the combination of the multikinase inhibitor lenvatinib and the PD-1 inhibitor pembrolizumab in this population (ClinicalTrials.gov identifier: NCT03776136). METHODS: Eligible patients with unresectable stage III-IV melanoma with confirmed progressive disease (PD) within 12 weeks of the last dose of a PD-1/L1 inhibitor given alone or with other therapies, including cytotoxic T-cell lymphocyte-associated antigen 4 (CTLA-4) inhibitors, received lenvatinib 20 mg orally once daily plus ≤ 35 doses of pembrolizumab 200 mg intravenously once every 3 weeks until PD or unacceptable toxicity. The primary end point was objective response rate (ORR) per RECIST, version 1.1, by independent central review. RESULTS: A total of 103 patients were enrolled and treated. The median study follow-up was 15.3 months. ORR in the total population was 21.4% (95% CI, 13.9 to 30.5), with three (2.9%) complete responses and 19 (18.4%) partial responses. The median duration of response was 8.3 months (range, 3.2-15.9+). ORR was 33.3% in the 30 patients with PD on prior anti-PD-1 plus anti-CTLA-4 therapy. The median progression-free survival and overall survival in the total population were 4.2 months (95% CI, 3.8 to 7.1) and 14.0 months (95% CI, 10.8 to not reached), respectively. Grade 3-5 treatment-related adverse events occurred in 47 (45.6%) patients, most commonly hypertension (21.4%); one patient died from a treatment-related event (decreased platelet count). CONCLUSION: Lenvatinib plus pembrolizumab provides clinically meaningful, durable responses in patients with advanced melanoma with confirmed PD on prior PD-1/L1 inhibitor-based therapy, including those with PD on anti-PD-1 plus anti-CTLA-4 therapy. The safety profile was as expected. These data support lenvatinib plus pembrolizumab as a potential regimen for this population of high unmet need.


Assuntos
Inibidores de Checkpoint Imunológico , Melanoma , Humanos , Inibidores de Checkpoint Imunológico/uso terapêutico , Antígeno B7-H1 , Melanoma/tratamento farmacológico , Proteínas Reguladoras de Apoptose/uso terapêutico , Melanoma Maligno Cutâneo
5.
Cancer Res ; 62(2): 386-90, 2002 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-11809685

RESUMO

The BCR protein is involved in the inhibition of oncogenic activity of the Bcr-Abl oncoprotein. This inhibition is believed to be the result of binding to the SH2 domain of Bcr-Abl in a non-phosphotyrosine-dependent manner. We showed that the Arg to Leu mutation in the Phe-Leu-Val-Arg-Glu-Ser (FLVRES) sequence of the SH2 domain, known to interfere with phosphotyrosine sequence binding, did not block the binding of Bcr first exon sequences to the Abl SH2 domain. We examined the structural-functional properties of a first exon mutant of BCR lacking the oligomerization domain, termed Bcr(64-413), that encodes the Ser-Thr protein kinase activity of Bcr. The autokinase product contained a M(r) 45,000-47,000 and 55,000 protein. Both species were detected by a Bcr phosphoserine 354 sequence-specific antibody. In contrast, the S354A mutant of Bcr(64-413), although maintaining autokinase activity, produced only the M(r) 45,000-47,000 kinase product. Abl SH2 binding experiments indicated that the M(r) 55,000 species of Bcr(64-413) but not the M(r) 45,000-47,000 species bound strongly to glutathime transferase-Abl SH2. The S354A mutant of Bcr(64-413) did not bind to glutathime transferase-Abl SH2. An adenovirus encoding Bcr(64-413) S354A did not induce cell death in CML cell lines in contrast to wild-type Bcr(64-413). Our findings indicate that Ser-354 of Bcr is part of a gating mechanism, which, after its phosphorylation, allows structural changes to occur in the Bcr protein. This altered phosphoserine form of the Bcr protein selectively binds to the Abl SH2 domain of the oncoprotein, which we propose down-regulates the activity of the Bcr-Abl tyrosine kinase.


Assuntos
Proteínas de Fusão bcr-abl/antagonistas & inibidores , Proteínas Oncogênicas/fisiologia , Fosfosserina/metabolismo , Proteínas Tirosina Quinases , Proteínas Proto-Oncogênicas , Sequência de Aminoácidos , Animais , Anticorpos/imunologia , Especificidade de Anticorpos , Células COS , Éxons , Proteínas de Fusão bcr-abl/genética , Proteínas de Fusão bcr-abl/metabolismo , Humanos , Células K562 , Peso Molecular , Mutação , Proteínas Oncogênicas/genética , Proteínas Oncogênicas/metabolismo , Fragmentos de Peptídeos/genética , Fragmentos de Peptídeos/imunologia , Fragmentos de Peptídeos/metabolismo , Fosfosserina/imunologia , Proteínas Proto-Oncogênicas c-bcr , Relação Estrutura-Atividade , Transfecção , Domínios de Homologia de src/genética , Domínios de Homologia de src/fisiologia
6.
Clin Colorectal Cancer ; 15(1): 67-73, 2016 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-26602596

RESUMO

INTRODUCTION/BACKGROUND: Rates of colorectal cancer screening are improving but remain suboptimal. Limited information is available regarding how patients are diagnosed with colorectal cancer (for example, asymptomatic screened patients or diagnostic workup because of the presence of symptoms). The purpose of this investigation was to determine how patients were diagnosed with colorectal cancer (screening colonoscopy, diagnostic colonoscopy, or emergent surgery) and tumor stage and size at diagnosis. PATIENTS AND METHODS: Adults evaluated between 2011 and 2014 with a diagnosis of colorectal cancer were identified. Clinical notes, endoscopy reports, surgical reports, radiology reports, and pathology reports were reviewed. Sex, race, ethnicity, age at the time of initial diagnosis, method of diagnosis, presenting symptom(s), and primary tumor size and stage at diagnosis were recorded. Colorectal cancer screening history was also recorded. RESULTS: The study population was 54% male (265 of 492) with a mean age of 58.9 years (range, 25-93 years). Initial tissue diagnosis was established at the time of screening colonoscopy in 10.7%, diagnostic colonoscopy in 79.2%, and during emergent surgery in 7.1%. Cancers diagnosed at the time of screening colonoscopy were more likely to be stage 1 than cancers diagnosed at the time of diagnostic colonoscopy or emergent surgery (38.5%, 7.2%, and 0%, respectively). Median tumor size was 3.0 cm for the screening colonoscopy group, 4.6 cm for the diagnostic colonoscopy group, and 5.0 cm for the emergent surgery group. At least 31% of patients diagnosed at the time of screening colonoscopy, 19% of patients diagnosed at the time of diagnostic colonoscopy, and 26% of patients diagnosed at the time of emergent surgery had never undergone a screening colonoscopy. CONCLUSION: Nearly 90% of colorectal cancer patients were diagnosed after development of symptoms and had more advanced disease than asymptomatic screening patients. Colorectal cancer outcomes will be improved by improving rates of colorectal cancer screening.


Assuntos
Colonoscopia , Neoplasias Colorretais/diagnóstico , Detecção Precoce de Câncer , Emergências , Adulto , Idoso , Idoso de 80 Anos ou mais , Estudos de Coortes , Neoplasias Colorretais/patologia , Procedimentos Cirúrgicos do Sistema Digestório , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estadiamento de Neoplasias , Estudos Retrospectivos , Carga Tumoral
7.
Int J Radiat Oncol Biol Phys ; 96(2): 296-303, 2016 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-27475674

RESUMO

PURPOSE: A challenge in borderline resectable pancreatic cancer (BRPC) management is the high rate of positive posterior margins (PM). Stereotactic body radiation therapy (SBRT) allows for higher radiation delivery dose with conformity. This study evaluated the maximal tolerated dose with a dose escalation plan level up to 45 Gy using SBRT in BRPC. METHODS AND MATERIALS: A single-institution, 3 + 3 phase 1 clinical trial design was used to evaluate 4 dose levels of SBRT delivered in 3 fractions to the planning target volume (PTV) with a simultaneous in-field boost (SIB) to the PM. Dose level (DL) 1 was 30 Gy to the PTV, and for dose levels 2 through 4 (DL2-DL4) the dose was 36 Gy. The SIB dose to the PM was 6, 6, 7.5, and 9 Gy for DL-1, DL-2, DL-3, and DL-4, respectively. All patients received 4 treatments of modified FOLFIRINOX (fluorouracil, leucovorin, irinotecan, oxaliplatin) before SBRT. RESULTS: Thirteen patients with a median age of 64 years were enrolled. The median follow-up time was 18 months. The locations of the cancer were head (n=12) and uncinate/neck (n=1). One patient did not undergo SBRT. There were no grade 3 or 4 toxicities. Five patients did not undergo resection because of disease progression (1 local, 4 distant); 8 had R0 resection in the PM, and 5 of 8 had vessel reconstruction. Two patients had disease downstaged to T1 and T2 from T3 disease. Four patients are still alive, and 3 are disease free. The median overall survival for resected patients was not reached (9.3: not reached). CONCLUSION: The SBRT dose of 36 Gy with a 9-Gy SIB to the PM (total 45 Gy) delivered in 3 fractions is safe and well tolerated. The dose-limiting toxicity for a 45-Gy dose was not reached, and further dose escalations are needed in future trials.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/administração & dosagem , Fracionamento da Dose de Radiação , Neoplasias Pancreáticas/terapia , Lesões por Radiação/etiologia , Radiocirurgia/efeitos adversos , Radiocirurgia/métodos , Idoso , Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Camptotecina/administração & dosagem , Camptotecina/efeitos adversos , Camptotecina/análogos & derivados , Quimiorradioterapia/efeitos adversos , Quimiorradioterapia/métodos , Feminino , Fluoruracila/administração & dosagem , Fluoruracila/efeitos adversos , Humanos , Irinotecano , Leucovorina/administração & dosagem , Leucovorina/efeitos adversos , Estudos Longitudinais , Masculino , Pessoa de Meia-Idade , Compostos Organoplatínicos/administração & dosagem , Compostos Organoplatínicos/efeitos adversos , Oxaliplatina , Pancreatectomia , Neoplasias Pancreáticas/diagnóstico , Lesões por Radiação/diagnóstico , Radioterapia Adjuvante/métodos , Resultado do Tratamento
8.
Am J Clin Oncol ; 38(6): 543-9, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-24662267

RESUMO

PURPOSE: Colorectal cancer has a distinct clinicopathologic presentation in younger patients. The aim of this paper was to evaluate the outcome of younger (age below 50 y) and older patients with stage IV (advanced) colorectal cancer in the modern era of combination chemotherapy. METHODS: Cases of metastatic colorectal cancer reported in Surveillance, Epidemiology, and End Results registry (1973 to 2008) were reviewed. Demographics, tumor characteristics, and overall and cancer-specific survivals in patients below 50 and above 50 years of age were compared by Cox proportional hazard analyses. Joinpoint regression analysis was used to evaluate secular trends in 2-year survival. RESULTS: Younger patients had a greater proportion of negative clinicopathologic features (male sex, African American ethnicity, and signet ring or mucinous histology). In multivariate analysis, older age, male sex, African American ethnicity, right-sided tumors, and signet ring histology were associated with higher mortality risk. Younger patients had improved survival (hazard ratio 0.72; 95% confidence interval: 0.70-0.75) compared with older patients, whereas all patients experienced increased 2-year survival by joinpoint analysis beginning in 1999-2000. CONCLUSIONS: The results confirm decreased mortality from advanced colorectal cancer in the era of modern combination chemotherapy in younger and older patients. Younger age, non-right-sided tumors, and absence of signet ring histology significantly associate with better survival.


Assuntos
Adenocarcinoma Mucinoso/mortalidade , Adenocarcinoma/mortalidade , Negro ou Afro-Americano/estatística & dados numéricos , Carcinoma de Células em Anel de Sinete/mortalidade , Neoplasias Colorretais/mortalidade , População Branca/estatística & dados numéricos , Adenocarcinoma/patologia , Adenocarcinoma Mucinoso/patologia , Adulto , Fatores Etários , Carcinoma de Células em Anel de Sinete/patologia , Neoplasias Colorretais/patologia , Humanos , Pessoa de Meia-Idade , Análise Multivariada , Estadiamento de Neoplasias , Prognóstico , Modelos de Riscos Proporcionais , Fatores de Risco , Programa de SEER , Fatores Sexuais , Resultado do Tratamento
9.
J Gastrointest Oncol ; 4(2): E1-4, 2013 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-23730521

RESUMO

Small cell carcinoma of the anus is a rare tumor that has been infrequently described in the literature. In contrast to squamous cell carcinoma, which is known to be associated with high-risk subtypes of human papillomavirus (HPV), the etiology of small cell carcinoma of the anal canal is not established. We present a case of a patient with small cell carcinoma of the anal canal in the setting of prior squamous dysplasia and carcinoma in situ. In conjunction with recently published data demonstrating the presence of HPV in tumor specimens from patients with small cell carcinoma of the anal canal, our patient's clinical course suggests a possible link between HPV and this rare malignancy.

10.
Pancreas ; 42(8): 1311-5, 2013 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-24152956

RESUMO

OBJECTIVES: FOLFIRINOX (5-fluorouracil [5-FU], oxaliplatin, and irinotecan) as compared with gemcitabine in pancreatic cancer (PC) has superior activity and increased toxicity. The bolus 5-FU contributes to the toxicity. We hypothesized that the elimination of bolus 5-FU and use of hematopoietic growth factor will improve the safety profile without compromising the activity of FOLFIRINOX. METHODS: Sixty patients with PC treated with modified FOLFIRINOX (no bolus 5-FU) were reviewed. Patients were divided into metastatic or nonmetastatic (locally advanced or borderline resectable) disease. Toxicity, response rate, progression-free survival, and overall survival were evaluated. RESULTS: Nonmetastatic and metastatic disease were present in 24 (40%) and 36 (60%) patients, respectively. The incidence of grade 4 neutropenia, grade 3/4 diarrhea, and fatigue were 3%, 13%, and 13%, respectively. Response rate was 30%. The median progression-free survival for nonmetastatic disease was 13.7 months (95% confidence interval [CI], 9.6-24.6 months), and that for metastatic disease was 8.5 months (95% CI, 3.7-11.0 months), respectively. The median overall survival for nonmetastatic disease was 17.8 months (95% CI, 9.9 months to not estimable), and that for metastatic disease was and 9.0 months (95% CI, 7.1 months to not estimable), respectively. CONCLUSIONS: Modified FOLFIRINOX has an improved safety profile with maintained efficacy in metastatic PC. Modified FOLFIRINOX has promising activity in nonmetastatic disease.


Assuntos
Adenocarcinoma/tratamento farmacológico , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Neoplasias Pancreáticas/tratamento farmacológico , Adenocarcinoma/metabolismo , Adulto , Idoso , Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Antígeno CA-19-9/metabolismo , Camptotecina/administração & dosagem , Camptotecina/efeitos adversos , Camptotecina/análogos & derivados , Diarreia/induzido quimicamente , Intervalo Livre de Doença , Relação Dose-Resposta a Droga , Fadiga/induzido quimicamente , Feminino , Filgrastim , Fluoruracila/administração & dosagem , Fluoruracila/efeitos adversos , Seguimentos , Fator Estimulador de Colônias de Granulócitos/administração & dosagem , Fator Estimulador de Colônias de Granulócitos/efeitos adversos , Humanos , Irinotecano , Leucovorina/administração & dosagem , Leucovorina/efeitos adversos , Masculino , Pessoa de Meia-Idade , Neutropenia/induzido quimicamente , Compostos Organoplatínicos/administração & dosagem , Compostos Organoplatínicos/efeitos adversos , Oxaliplatina , Neoplasias Pancreáticas/metabolismo , Polietilenoglicóis , Proteínas Recombinantes/administração & dosagem , Proteínas Recombinantes/efeitos adversos , Estudos Retrospectivos , Resultado do Tratamento
11.
Expert Opin Ther Targets ; 15(7): 859-72, 2011 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-21476875

RESUMO

INTRODUCTION: The mammalian target of rapamycin (mTOR)/PI3K/Akt pathway is altered in breast cancer cells, as demonstrated by mutations in both the upstream and downstream regulators of mTOR, including phosphatase and tensin homolog deleted in chromosome 10 (PTEN) loss or Akt/PI3K activation, and potentially in the mTOR protein itself. This contributes to increased cell proliferation, as well as growth-factor independence and endocrine resistance. Thus, mTOR inhibition holds considerable promise as a rational therapeutic strategy in breast cancer. AREAS COVERED: This review describes how dysregulation of the mTOR pathway in breast cancer may contribute to breast cancer pathogenesis, as well as discussing preclinical and clinical data that support mTOR inhibitor therapy. EXPERT OPINION: Direct blockade of the mTOR pathway is a new and intriguing area in breast cancer therapy, with the potential to modulate growth-factor and estrogen-dependent and -independent pathways, that contribute to the pathogenesis and progression of breast tumors. mTOR inhibitors demonstrate significant biologic activity with manageable toxicities, in combination with hormonal therapy and chemotherapy, in both the neoadjuvant and metastatic breast cancer settings.


Assuntos
Antineoplásicos/farmacologia , Neoplasias da Mama/tratamento farmacológico , Transdução de Sinais , Serina-Treonina Quinases TOR/antagonistas & inibidores , Antineoplásicos/uso terapêutico , Neoplasias da Mama/enzimologia , Neoplasias da Mama/metabolismo , Feminino , Humanos , Fosfatidilinositol 3-Quinases/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo
12.
Cancer Biol Ther ; 7(12): 1952-8, 2008 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-18981735

RESUMO

The mammalian target of rapamycin (mTOR) has emerged as an important cancer therapeutic target. Several mTOR inhibitors are currently being tested in cancer clinical trials. Both PI3K/Akt and MEK/ERK signaling regulate mTOR axis. However, inhibition of mTOR activates Akt survival signaling, which in turn attenuates mTOR inhibitors' anticancer efficacy. We are interested in developing strategies for enhancing mTOR-targeted cancer therapy. In this study, we report that mTOR inhibition also induced activations of the MEK/ERK signaling pathway in some cancer cell lines after a prolonged treatment. The combination of rapamycin with the MEK inhibitor U0126 significantly enhanced growth inhibitory effects of cancer cells, suggesting that MEK/ERK activation may counteract mTOR inhibitors' anticancer efficacy. Similarly, the combination of an mTOR inhibitor with the EGF receptor inhibitor erlotinib synergistically inhibited the growth of both human cancer cells in cell cultures and xenografts in nude mice. Moreover, the presence of erlotinib suppressed rapamycin-induced phosphorylation of Akt, ERK and eIF4E as well, implying that erlotinib can suppress mTOR inhibition-induced feedback activation of several survival signaling pathways including Akt, ERK and eIF4E. Thus, we suggest a therapeutic strategy for enhancing mTOR-targeted cancer therapy by preventing mTOR inhibition-induced feedback activation of several survival mechanisms.


Assuntos
Antineoplásicos/uso terapêutico , Neoplasias/tratamento farmacológico , Proteínas Quinases/metabolismo , Sirolimo/análogos & derivados , Antibióticos Antineoplásicos/uso terapêutico , Antineoplásicos/metabolismo , Carcinoma de Células Renais/tratamento farmacológico , Linhagem Celular Tumoral , Sobrevivência Celular , Inibidores Enzimáticos/farmacologia , Cloridrato de Erlotinib , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Humanos , Neoplasias Renais/tratamento farmacológico , Inibidores de Proteínas Quinases/uso terapêutico , Proteínas Quinases/uso terapêutico , Quinazolinas/uso terapêutico , Transdução de Sinais , Sirolimo/uso terapêutico , Serina-Treonina Quinases TOR
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