RESUMEN
Mitogen-activated protein kinase kinase 3 (MKK3) is a dual threonine/tyrosine protein kinase that regulates inflammation, proliferation and apoptosis through specific phosphorylation and activation of the p38 mitogen-activated protein kinase. However, the role of MKK3 beyond p38-signaling remains elusive. Recently, we reported a protein-protein interaction (PPI) network of cancer-associated genes, termed OncoPPi, as a resource for the scientific community to generate new biological models. Analysis of the OncoPPi connectivity identified MKK3 as one of the major hub proteins in the network. Here, we show that MKK3 interacts with a large number of proteins critical for cell growth and metabolism, including the major oncogenic driver MYC. Multiple complementary approaches were used to demonstrate the direct interaction of MKK3 with MYC in vitro and in vivo. Computational modeling and experimental studies mapped the interaction interface to the MYC helix-loop-helix domain and a novel 15-residue MYC-binding motif in MKK3 (MBM). The MBM in MKK3 is distinct from the known binding sites for p38 or upstream kinases. Functionally, MKK3 stabilized MYC protein, enhanced its transcriptional activity and increased expression of MYC-regulated genes. The defined MBM peptide mimicked the MKK3 effect in promoting MYC activity. Together, the exploration of OncoPPi led to a new biological model in which MKK3 operates by two distinct mechanisms in cellular regulation through its phosphorylation of p38 and its activation of MYC through PPI.
Asunto(s)
Proteínas de Unión al ADN/metabolismo , Neoplasias Pulmonares/metabolismo , MAP Quinasa Quinasa 3/metabolismo , Mapas de Interacción de Proteínas , Factores de Transcripción/metabolismo , Línea Celular Tumoral , Proteínas de Unión al ADN/química , Proteínas de Unión al ADN/genética , Bases de Datos de Proteínas , Activación Enzimática , Humanos , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/patología , MAP Quinasa Quinasa 3/genética , Fosforilación , Conformación Proteica , Transducción de Señal/genética , Factores de Transcripción/química , Factores de Transcripción/genética , Proteínas Quinasas p38 Activadas por Mitógenos/metabolismoRESUMEN
Metastases remain the major cause of death from cancer. Recent molecular advances have highlighted the importance of metabolic alterations in cancer cells, including the Warburg effect that describes an increased glycolysis in cancer cells. However, how this altered metabolism contributes to tumour metastasis remains elusive. Here, we report that phosphorylation-induced activation of lactate dehydrogenase A (LDHA), an enzyme that catalyses the interconversion of pyruvate and lactate, promotes cancer cell invasion, anoikis resistance and tumour metastasis. We demonstrate that LDHA is phosphorylated at tyrosine 10 by upstream kinases, HER2 and Src. Targeting HER2 or Src attenuated LDH activity as well as invasive potential in head and neck cancer and breast cancer cells. Inhibition of LDH activity by small hairpin ribonucleic acid or expression of phospho-deficient LDHA Y10F sensitized the cancer cells to anoikis induction and resulted in attenuated cell invasion and elevated reactive oxygen species, whereas such phenotypes were reversed by its product lactate or antioxidant N-acetylcysteine, suggesting that Y10 phosphorylation-mediated LDHA activity promotes cancer cell invasion and anoikis resistance through redox homeostasis. In addition, LDHA knockdown or LDHA Y10F rescue expression in human cancer cells resulted in decreased tumour metastasis in xenograft mice. Furthermore, LDHA phosphorylation at Y10 positively correlated with progression of metastatic breast cancer in clinical patient tumour samples. Our findings demonstrate that LDHA phosphorylation and activation provide pro-invasive, anti-anoikis and pro-metastatic advantages to cancer cells, suggesting that Y10 phosphorylation of LDHA may represent a promising therapeutic target and a prognostic marker for metastatic human cancers.
Asunto(s)
Neoplasias de la Mama/enzimología , L-Lactato Deshidrogenasa/metabolismo , Procesamiento Proteico-Postraduccional , Animales , Anoicis/efectos de los fármacos , Antineoplásicos/farmacología , Benzodioxoles/farmacología , Neoplasias de la Mama/patología , Línea Celular Tumoral , Proliferación Celular , Activación Enzimática , Femenino , Humanos , Isoenzimas/genética , Isoenzimas/metabolismo , L-Lactato Deshidrogenasa/genética , Lactato Deshidrogenasa 5 , Metástasis Linfática , Ratones Desnudos , Invasividad Neoplásica , Trasplante de Neoplasias , Fosforilación , Quinazolinas/farmacología , Especies Reactivas de Oxígeno , Receptor ErbB-2/metabolismo , Familia-src Quinasas/metabolismoRESUMEN
The oxidative pentose phosphate pathway (PPP) is crucial for cancer cell metabolism and tumor growth. We recently reported that targeting a key oxidative PPP enzyme, 6-phosphogluconate dehydrogenase (6PGD), using our novel small-molecule 6PGD inhibitors Physcion and its derivative S3, shows anticancer effects. Notably, humans with genetic deficiency of either 6PGD or another oxidative PPP enzyme, glucose-6-phosphate dehydrogenase, exhibit non-immune hemolytic anemia upon exposure to aspirin and various antimalarial drugs. Inspired by these clinical observations, we examined the anticancer potential of combined treatment with 6PGD inhibitors and antimalarial drugs. We found that stable knockdown of 6PGD sensitizes leukemia cells to antimalarial agent dihydroartemisinin (DHA). Combined treatment with DHA and Physcion activates AMP-activated protein kinase, leading to synergistic inhibition of human leukemia cell viability. Moreover, our combined therapy synergistically attenuates tumor growth in xenograft nude mice injected with human K562 leukemia cells and cell viability of primary leukemia cells from human patients, but shows minimal toxicity to normal hematopoietic cells in mice as well as red blood cells and mononucleocytes from healthy human donors. Our findings reveal the potential for combined therapy using optimized doses of Physcion and DHA as a novel antileukemia treatment without inducing hemolysis.
Asunto(s)
Antimaláricos/administración & dosificación , Protocolos de Quimioterapia Combinada Antineoplásica/administración & dosificación , Emodina/análogos & derivados , Leucemia/tratamiento farmacológico , Vía de Pentosa Fosfato/efectos de los fármacos , Fosfogluconato Deshidrogenasa/antagonistas & inhibidores , Animales , Antimaláricos/farmacología , Protocolos de Quimioterapia Combinada Antineoplásica/farmacología , Artemisininas/administración & dosificación , Artemisininas/farmacología , Línea Celular Tumoral , Supervivencia Celular/efectos de los fármacos , Sinergismo Farmacológico , Emodina/administración & dosificación , Emodina/farmacología , Femenino , Humanos , Células K562 , Leucemia/enzimología , Ratones , Ratones Desnudos , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
Metastasis is responsible for >90% of cancer-related deaths. Complex signaling in cancer cells orchestrates the progression from a primary to a metastatic cancer. However, the mechanisms of these cellular changes remain elusive. We previously demonstrated that p90 ribosomal S6 kinase 2 (RSK2) promotes tumor metastasis. Here we investigated the role of RSK2 in the regulation of microtubule dynamics and its potential implication in cancer cell invasion and tumor metastasis. Stable knockdown of RSK2 disrupted microtubule stability and decreased phosphorylation of stathmin, a microtubule-destabilizing protein, at serine 16 in metastatic human cancer cells. We found that RSK2 directly binds and phosphorylates stathmin at the leading edge of cancer cells. Phosphorylation of stathmin by RSK2 reduced stathmin-mediated microtubule depolymerization. Moreover, overexpression of phospho-mimetic mutant stathmin S16D significantly rescued the decreased invasive and metastatic potential mediated by RSK2 knockdown in vitro and in vivo. Furthermore, stathmin phosphorylation positively correlated with RSK2 expression and metastatic cancer progression in primary patient tumor samples. Our finding demonstrates that RSK2 directly phosphorylates stathmin and regulates microtubule polymerization to provide a pro-invasive and pro-metastatic advantage to cancer cells. Therefore, the RSK2-stathmin pathway represents a promising therapeutic target and a prognostic marker for metastatic human cancers.
Asunto(s)
Neoplasias Pulmonares/genética , Metástasis de la Neoplasia/genética , Proteínas Quinasas S6 Ribosómicas 90-kDa/genética , Estatmina/genética , Células A549 , Movimiento Celular/genética , Técnicas de Silenciamiento del Gen , Humanos , Neoplasias Pulmonares/patología , Microtúbulos/genética , Microtúbulos/patología , Invasividad Neoplásica/genética , Invasividad Neoplásica/patología , Metástasis de la Neoplasia/patología , Fosforilación , Proteínas Quinasas S6 Ribosómicas 90-kDa/metabolismo , Transducción de Señal , Estatmina/metabolismoRESUMEN
Cancer cells feature increased de novo lipogenesis. Sterol regulatory element-binding protein 1 (SREBP1), when presented in its mature form (mSREBP1), enhances lipogenesis by increasing transcription of several of its target genes. Mammalian target of rapamycin (mTOR) complexes, mTORC1 and mTORC2, are master regulators of cellular survival, growth and metabolism. A role for mTORC1 in the regulation of SREBP1 activity has been suggested; however, the connection between mTORC2 and SREBP1 has not been clearly established and hence is the focus of this study. mTOR kinase inhibitors (for example, INK128), which inhibit both mTORC1 and mTORC2, decreased mSREBP1 levels in various cancer cell lines. Knockdown of rictor, but not raptor, also decreased mSREBP1. Consistently, reduced mSREBP1 levels were detected in cells deficient in rictor or Sin1 compared with parent or rictor-deficient cells with re-expression of ectopic rictor. Hence it is mTORC2 inhibition that causes mSREBP1 reduction. As a result, expression of the mSREBP1 target genes acetyl-CoA carboxylase and fatty-acid synthase was suppressed, along with suppressed lipogenesis in cells exposed to INK128. Moreover, mSREBP1 stability was reduced in cells treated with INK128 or rictor knockdown. Inhibition of proteasome, GSK3 or the E3 ubiquitin ligase, FBXW7, prevented mSREBP1 reduction induced by mTORC2 inhibition. Thus mTORC2 inhibition clearly facilitates GSK3-dependent, FBXW7-mediated mSREBP1 degradation, leading to mSREBP1 reduction. Accordingly, we conclude that mTORC2 positively regulates mSREBP1 stability and lipogenesis. Our findings reveal a novel biological function of mTORC2 in the regulation of lipogenesis and warrant further study in this direction.
Asunto(s)
Proteínas de Ciclo Celular/metabolismo , Proteínas F-Box/metabolismo , Glucógeno Sintasa Quinasa 3/metabolismo , Complejos Multiproteicos/antagonistas & inhibidores , Proteína 1 de Unión a los Elementos Reguladores de Esteroles/metabolismo , Serina-Treonina Quinasas TOR/antagonistas & inhibidores , Ubiquitina-Proteína Ligasas/metabolismo , Proteínas de Ciclo Celular/genética , Línea Celular Tumoral , Inhibidores Enzimáticos/farmacología , Proteínas F-Box/genética , Proteína 7 que Contiene Repeticiones F-Box-WD , Técnicas de Silenciamiento del Gen , Células HCT116 , Humanos , Indoles/farmacología , Lipogénesis , Maleimidas/farmacología , Diana Mecanicista del Complejo 2 de la Rapamicina , Complejos Multiproteicos/metabolismo , Neoplasias/tratamiento farmacológico , Neoplasias/metabolismo , Neoplasias/patología , Serina-Treonina Quinasas TOR/metabolismo , Transfección , Ubiquitina-Proteína Ligasas/genéticaRESUMEN
Inhibition of B-Raf/MEK/ERK signaling is an effective therapeutic strategy against certain types of cancers such as melanoma and thyroid cancer. While demonstrated to be effective anticancer agents, B-Raf or MEK inhibitors have also been associated with early tumor progression and development of secondary neoplasms. The ligation of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) with its receptor, death receptor 5 (DR5), leading to induction of apoptosis, offers a promising anticancer strategy. Importantly, this is also a natural immunosurveillance mechanism against cancer development. We previously demonstrated that activated B-Raf/MEK/ERK signaling positively regulates DR5 expression. Hence, our current work sought to address whether B-Raf/MEK/ERK inhibition and the consequent suppression of DR5 expression impede cancer cell response to DR5 activation-induced apoptosis and activated immune cell-induced killing. We found that both B-Raf (for example, PLX4032) and MEK inhibitors (for example, AZD6244 and PD0325901) effectively inhibited ERK1/2 phosphorylation and reduced DR5 levels in both human thyroid cancer and melanoma cells. Similar to the observed effect of genetic knockdown of the B-Raf gene, pre-treatment of cancer cell lines with either B-Raf or MEK inhibitors attenuated or abolished cellular apoptotic response induced by TRAIL or the DR5 agonistic antibody AMG655 or cell killing by activated T cells. Our findings clearly show that inhibition of B-Raf/MEK/ERK signaling suppresses DR5 expression and impairs DR5 activation-induced apoptosis and T cell-mediated killing of cancer cells. These findings suggest a potential negative impact of B-Raf or MEK inhibition on TRAIL- or DR5-mediated anticancer therapy and on TRAIL/DR5-mediated immune-clearance of cancer cells.
Asunto(s)
Inhibidores Enzimáticos/farmacología , Quinasas MAP Reguladas por Señal Extracelular/metabolismo , Quinasas Quinasa Quinasa PAM/metabolismo , Proteínas Proto-Oncogénicas B-raf/antagonistas & inhibidores , Receptores del Ligando Inductor de Apoptosis Relacionado con TNF/metabolismo , Apoptosis/efectos de los fármacos , Bencimidazoles/farmacología , Línea Celular Tumoral/efectos de los fármacos , Quinasas MAP Reguladas por Señal Extracelular/antagonistas & inhibidores , Humanos , Indoles/farmacología , Quinasas Quinasa Quinasa PAM/antagonistas & inhibidores , Proteínas Proto-Oncogénicas B-raf/genética , Proteínas Proto-Oncogénicas B-raf/metabolismo , ARN Interferente Pequeño , Receptores del Ligando Inductor de Apoptosis Relacionado con TNF/genética , Transducción de Señal/efectos de los fármacos , Sulfonamidas/farmacología , Linfocitos T/efectos de los fármacos , Linfocitos T/metabolismo , Ligando Inductor de Apoptosis Relacionado con TNF/metabolismo , VemurafenibRESUMEN
BACKGROUND: This trial was designed to evaluate the activity and safety of ganetespib in combination with docetaxel in advanced non-small cell lung cancer (NSCLC) and to identify patient populations most likely to benefit from the combination. PATIENTS AND METHODS: Patients with one prior systemic therapy for advanced disease were eligible. Docetaxel (75 mg/m(2) on day 1) was administered alone or with ganetespib (150 mg/m(2) on days 1 and 15) every 3 weeks. The primary end points were progression-free survival (PFS) in two subgroups of the adenocarcinoma population: patients with elevated lactate dehydrogenase (eLDH) and mutated KRAS (mKRAS). RESULTS: Of 385 patients enrolled, 381 were treated. Early in the trial, increased hemoptysis and lack of efficacy were observed in nonadenocarcinoma patients (n = 71); therefore, only patients with adenocarcinoma histology were subsequently enrolled. Neutropenia was the most common grade ≥3 adverse event: 41% in the combination arm versus 42% in docetaxel alone. There was no improvement in PFS for the combination arm in the eLDH (N = 114, adjusted hazard ratio (HR) = 0.77, P = 0.1134) or mKRAS (N = 89, adjusted HR = 1.11, P = 0.3384) subgroups. In the intent-to-treat adenocarcinoma population, there was a trend in favor of the combination, with PFS (N = 253, adjusted HR = 0.82, P = 0.0784) and overall survival (OS) (adjusted HR = 0.84, P = 0.1139). Exploratory analyses showed significant benefit of the ganetespib combination in the prespecified subgroup of adenocarcinoma patients diagnosed with advanced disease >6 months before study entry (N = 177): PFS (adjusted HR = 0.74, P = 0.0417); OS (adjusted HR = 0.69, P = 0.0191). CONCLUSION: Advanced lung adenocarcinoma patients treated with ganetespib in combination with docetaxel had an acceptable safety profile. While the study's primary end points were not met, significant prolongation of PFS and OS was observed in patients >6 months from diagnosis of advanced disease, a subgroup chosen as the target population for the phase III study.
Asunto(s)
Adenocarcinoma/tratamiento farmacológico , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Carcinoma de Pulmón de Células no Pequeñas/tratamiento farmacológico , Neoplasias Pulmonares/tratamiento farmacológico , Adenocarcinoma/genética , Adenocarcinoma/metabolismo , Adenocarcinoma/patología , Anciano , Carcinoma de Pulmón de Células no Pequeñas/metabolismo , Carcinoma de Pulmón de Células no Pequeñas/patología , Supervivencia sin Enfermedad , Docetaxel , Femenino , Proteínas HSP90 de Choque Térmico/antagonistas & inhibidores , Humanos , L-Lactato Deshidrogenasa/metabolismo , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/metabolismo , Neoplasias Pulmonares/patología , Masculino , Persona de Mediana Edad , Modelos de Riesgos Proporcionales , Proteínas Proto-Oncogénicas p21(ras)/genética , Taxoides/administración & dosificación , Resultado del Tratamiento , Triazoles/administración & dosificaciónRESUMEN
The cyclin-dependent kinase (CDK) inhibitor 1A, p21/Cip1, is a vital cell cycle regulator, dysregulation of which has been associated with a large number of human malignancies. One critical mechanism that controls p21 function is through its degradation, which allows the activation of its associated cell cycle-promoting kinases, CDK2 and CDK4. Thus delineating how p21 is stabilized and degraded will enhance our understanding of cell growth control and offer a basis for potential therapeutic interventions. Here we report a novel regulatory mechanism that controls the dynamic status of p21 through its interaction with Cdk5 and Abl enzyme substrate 1 (Cables1). Cables1 has a proposed role as a tumor suppressor. We found that upregulation of Cables1 protein was correlated with increased half-life of p21 protein, which was attributed to Cables1/p21 complex formation and supported by their co-localization in the nucleus. Mechanistically, Cables1 interferes with the proteasome (Prosome, Macropain) subunit alpha type 3 (PSMA3) binding to p21 and protects p21 from PSMA3-mediated proteasomal degradation. Moreover, silencing of p21 partially reverses the ability of Cables1 to induce cell death and inhibit cell proliferation. In further support of a potential pathophysiological role of Cables1, the expression level of Cables1 is tightly associated with p21 in both cancer cell lines and human lung cancer patient tumor samples. Together, these results suggest Cables1 as a novel p21 regulator through maintaining p21 stability and support the model that the tumor-suppressive function of Cables1 occurs at least in part through enhancing the tumor-suppressive activity of p21.
Asunto(s)
Proteínas Portadoras/metabolismo , Inhibidor p21 de las Quinasas Dependientes de la Ciclina/metabolismo , Ciclinas/metabolismo , Neoplasias Pulmonares/patología , Fosfoproteínas/metabolismo , Proteínas Supresoras de Tumor/metabolismo , Apoptosis/genética , Proteínas Portadoras/biosíntesis , Proteínas Portadoras/genética , Línea Celular Tumoral , Proliferación Celular/genética , Quinasa 2 Dependiente de la Ciclina/metabolismo , Quinasa 4 Dependiente de la Ciclina/metabolismo , Inhibidor p21 de las Quinasas Dependientes de la Ciclina/genética , Ciclinas/biosíntesis , Ciclinas/genética , Células HEK293 , Humanos , Neoplasias Pulmonares/genética , Fosfoproteínas/biosíntesis , Fosfoproteínas/genética , Complejo de la Endopetidasa Proteasomal/metabolismo , Unión Proteica , Proteolisis , Interferencia de ARN , ARN Interferente Pequeño , Proteínas Supresoras de Tumor/genéticaRESUMEN
Mcl-1 is a unique antiapoptotic Bcl2 family member with a short half-life due to its rapid turnover through ubiquitination. We discovered that Ku70, a DNA double-strand break repair protein, functions as a deubiquitinase to stabilize Mcl-1. Ku70 knockout in mouse embryonic fibroblast (MEF) cells or depletion from human lung cancer H1299 cells leads to the accumulation of polyubiquitinated Mcl-1 and a reduction in its half-life and protein expression. Conversely, expression of exogenous Ku70 in Ku70(-/-) MEF cells restores Mcl-1 expression. Subcellular fractionation indicates that Ku70 extensively colocalizes with Mcl-1 in mitochondria, endoplasmic reticulum and nucleus in H1299 cells. Ku70 directly interacts with Mcl-1 via its C terminus (that is, aa 536-609), which is required and sufficient for deubiquitination and stabilization of Mcl-1, leading to suppression of apoptosis. Purified Ku70 protein directly deubiquitinates Mcl-1 by removing K48-linked polyubiquitin chains. Ku70 knockdown not only promotes Mcl-1 turnover but also enhances antitumor efficacy of the BH3-mimetic ABT-737 in human lung cancer xenografts. These findings identify Ku70 as a novel Mcl-1 deubiquitinase that could be a potential target for cancer therapy by manipulating Mcl-1 deubiquitination.
Asunto(s)
Antígenos Nucleares/fisiología , Apoptosis , Proteínas de Unión al ADN/fisiología , Proteína 1 de la Secuencia de Leucemia de Células Mieloides/metabolismo , Ubiquitinación , Animales , Antineoplásicos/farmacología , Compuestos de Bifenilo/farmacología , Supervivencia Celular , Células HCT116 , Células HEK293 , Semivida , Humanos , Autoantígeno Ku , Ratones , Ratones Desnudos , Nitrofenoles/farmacología , Piperazinas/farmacología , Dominios y Motivos de Interacción de Proteínas , Estabilidad Proteica , Transporte de Proteínas , Estaurosporina/farmacología , Sulfonamidas/farmacología , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
BACKGROUND: This phase 1 trial utilising a Bayesian continual reassessment method evaluated bortezomib and sunitinib to determine the maximum tolerated dose (MTD), dose-limiting toxicities (DLT), and recommended doses of the combination. METHODS: Patients with advanced solid organ malignancies were enrolled and received bortezomib weekly with sunitinib daily for 4 weeks, every 6 weeks. Initial doses were sunitinib 25 mg and bortezomib 1 mg m(-2). Cohort size and dose level estimation was performed utilising the Escalation with Overdose Control (EWOC) adaptive method. Seven dose levels were evaluated; initially, sunitinib was increased to a goal dose of 50 mg with fixed bortezomib, then bortezomib was increased. Efficacy assessment occurred after each cycle using RECIST criteria. RESULTS: Thirty patients were evaluable. During sunitinib escalation, DLTs of grade 4 thrombocytopenia (14%) and neutropenia (6%) at sunitinib 50 mg and bortezomib 1.3 mg m(-2) were seen. Subsequent experience showed tolerability and activity for sunitinib 37.5 mg and bortezomib 1.9 mg m(-2). Common grade 3/4 toxicities were neutropenia, thrombocytopenia, hypertension, and diarrhoea. The recommended doses for further study are bortezomib 1.9 mg m(-2) and sunitinib 37.5 mg. Four partial responses were seen. Stable disease >6 months was noted in an additional six patients. CONCLUSION: Bortezomib and sunitinib are well tolerated and have anticancer activity, particularly in thyroid cancer. A phase 2 study of this combination in thyroid cancer patients is planned.
Asunto(s)
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Ácidos Borónicos/administración & dosificación , Indoles/administración & dosificación , Pirazinas/administración & dosificación , Pirroles/administración & dosificación , Adulto , Anciano , Anciano de 80 o más Años , Protocolos de Quimioterapia Combinada Antineoplásica/efectos adversos , Teorema de Bayes , Bortezomib , Esquema de Medicación , Femenino , Humanos , Masculino , Dosis Máxima Tolerada , Persona de Mediana Edad , Neoplasias/tratamiento farmacológico , Sunitinib , Neoplasias de la Tiroides/tratamiento farmacológicoRESUMEN
Cancer progression involves multiple complex and interdependent steps, including progressive proliferation, angiogenesis and metastases. The complexity of these processes requires a comprehensive elucidation of the integrated signaling networks for better understanding. EAPII interacts with multiple cancer-related proteins, but its biological significance in cancer development remains unknown. In this report we identified the elevated level of EAPII protein in non-small-cell lung carcinoma (NSCLC) patients and NSCLC cell lines in culture. The oncogenic role of EAPII in lung cancer development was demonstrated using NSCLC cells with genetic manipulations that influence EAPII expression: EAPII overexpression increases proliferation of NSCLC cells with an accelerated transition of cell cycle and facilitates xenograft tumor growth in vivo; EAPII knockdown results in apoptosis of NSCLC cells and reduces xenograft tumor formation. To further explore the mechanism of EAPII's oncogenic role in lung cancer development and to elucidate the potential signaling pathway(s) that EAPII may impact, we employed antibody array to investigate the alternation of the major signaling pathways in NSCLC cells with altered EAPII level. We found that EAPII overexpression significantly activated Raf1 and ERK1/2, but not c-Jun N-terminal kinase and p38 pathways. Consistently, the protein and mRNA levels of MYC and cyclin D1, which are targets of the mitogen-activated protein kinase/extracellular signal-regulated kinase (MAPK-ERK) pathway, are significantly increased by EAPII overexpression. Taken together, we demonstrated that EAPII is an oncogenic factor and the activation of MAPK-ERK signaling pathway by EAPII may contribute to lung cancer development.
Asunto(s)
Carcinoma de Pulmón de Células no Pequeñas/metabolismo , Neoplasias Pulmonares/metabolismo , Quinasas de Proteína Quinasa Activadas por Mitógenos/biosíntesis , Proteínas Nucleares/fisiología , Oncogenes/fisiología , Factores de Transcripción/fisiología , Apoptosis/genética , Carcinoma de Pulmón de Células no Pequeñas/genética , Carcinoma de Pulmón de Células no Pequeñas/patología , Línea Celular Tumoral , Proliferación Celular , Proteínas de Unión al ADN , Activación Enzimática , Técnicas de Silenciamiento del Gen , Humanos , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/patología , Proteínas Nucleares/genética , Oncogenes/genética , Hidrolasas Diéster Fosfóricas , Factores de Transcripción/genéticaRESUMEN
Faithful and efficient transmission of biological signals through mitogen-activated protein kinase (MAPK) pathways requires engagement of highly regulated cellular machinery in response to diverse environmental cues. Here, we report a novel mechanism controlling signal relay between two MAP3Ks, apoptosis signal-regulating kinase (ASK) 1 and ASK2. We show that ASK2 specifically interacts with 14-3-3 proteins through phosphorylated S964. Although a 14-3-3-binding defective mutant of ASK1 (S967A) has no effect on the ASK2/14-3-3 interaction, both overexpression of the analogous ASK2 (S964A) mutant and knockdown of ASK2 dramatically reduced the amount of ASK1 complexed with 14-3-3. These data suggest a dominant role of ASK2 in 14-3-3 control of ASK1 function. Indeed, ASK2 S964A-induced dissociation of 14-3-3 from ASK1 correlated with enhanced phosphorylation of ASK1 at T838 and increased c-Jun N-terminal kinase phosphorylation, the two biological readouts of ASK1 activation. Our results suggest a model in which upstream signals couple ASK2 S964 phosphorylation to the ASK1 signalosome through dual engagement of 14-3-3.
Asunto(s)
Proteínas 14-3-3/metabolismo , MAP Quinasa Quinasa Quinasa 5/metabolismo , Quinasas Quinasa Quinasa PAM/metabolismo , Transducción de Señal , Secuencias de Aminoácidos , Secuencia de Aminoácidos , Animales , Células COS , Chlorocebus aethiops , Células HeLa , Humanos , Quinasas Quinasa Quinasa PAM/química , Fosforilación , Especificidad por SustratoRESUMEN
Chronic myelomonocytic leukaemia (CMML) is a preleukaemic condition with myeloproliferative features, and classified as a part of myelodysplastic syndrome (MDS). Other than alkylating agents and topoisomerase II inhibitors, there is less evidence that chemotherapeutic drugs are associated with therapy-related CMML, acute leukaemia or MDS. We present a patient who developed CMML within 2 years of platinum-based chemotherapy for a metastatic non-small cell lung cancer. He received a cumulative dose of 240 mg/m(2) of cisplatin, and 1123 mg/m(2) of carboplatin before developing CMML. The cytogenetic study revealed trisomy 8. This is the first reported case that links platinum-based therapy with development of CMML with trisomy 8. Although the relationship between platinum therapy and the development of CMML is difficult to assess due to combinational nature of therapy in most cases, physicians should consider the possibility of CMML in patients with symptoms or signs suggestive of haematologic malignancy after platinum therapy.
Asunto(s)
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Carcinoma de Pulmón de Células no Pequeñas/tratamiento farmacológico , Cisplatino/efectos adversos , Leucemia Mielomonocítica Crónica/inducido químicamente , Neoplasias Pulmonares/tratamiento farmacológico , Etopósido/administración & dosificación , Resultado Fatal , Humanos , Leucemia Mielomonocítica Crónica/fisiopatología , Masculino , Persona de Mediana EdadRESUMEN
BACKGROUND: R115777 (tipifarnib, Zarnestra) is a farnesyl transferase inhibitor that blocks the farnesylation of proteins involved in signal transduction pathways critical for cell proliferation and survival. This multicenter phase II study was conducted to determine the efficacy, tolerability and pharmacokinetics of R115777 in patients with relapsed small-cell lung cancer (SCLC). PATIENTS AND METHODS: Patients who had a partial or complete response to their initial chemotherapy regimen, followed by at least 3 months off treatment before relapse (sensitive relapse) were eligible. R115777 was administered in 3-week cycles at a dose of 400 mg orally twice daily for 14 consecutive days followed by 7 days off treatment. RESULTS: Twenty-two patients were enrolled. The median progression-free survival was 1.4 months and median overall survival was 6.8 months. Non-hematological toxicities were predominantly grade 1-2 and included nausea (64%) and fatigue (60%). Grade 3-4 granulocytopenia and thrombocytopenia occurred in 27% and 23% of patients, respectively. Febrile neutropenia was not observed. Pharmacokinetic studies demonstrated peak plasma concentrations of R115777 2.6-4.5 h after oral dosing and no significant drug accumulation. The trial was terminated because no objective responses were observed in 20 patients evaluable for response. CONCLUSIONS: R115777 showed no significant antitumor activity as a single agent in sensitive-relapse SCLC.
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Carcinoma de Células Pequeñas/tratamiento farmacológico , Neoplasias Pulmonares/tratamiento farmacológico , Quinolonas/uso terapéutico , Adulto , Anciano , Anciano de 80 o más Años , Transferasas Alquil y Aril/antagonistas & inhibidores , Transferasas Alquil y Aril/farmacología , Carcinoma de Células Pequeñas/patología , Supervivencia sin Enfermedad , Farnesiltransferasa , Femenino , Humanos , Neoplasias Pulmonares/patología , Masculino , Persona de Mediana Edad , Quinolonas/efectos adversos , Quinolonas/farmacocinética , Recurrencia , Transducción de Señal , Resultado del TratamientoRESUMEN
The ras family of proto-oncogenes are upstream mediators of several essential cellular signal transduction pathways involved in cell proliferation and survival. Point mutations of ras oncogenes result in constitutively active Ras and have been shown to be oncogenic. However, ras activation can occur in the absence of ras mutations secondary to upstream receptor activation. The first important step in Ras activation is farnesylation by farnesyl transferase, and inhibitors of this enzyme have been demonstrated to inhibit Ras signaling, and have anti-tumor effects. However, it is now clear that farnesyl transferase inhibitors (FTIs) have activity independent of Ras, most likely due to effects on prenylated proteins downstream of Ras, which explains their activity in several malignancies, including breast cancer, where ras mutations are rare. Several FTIs are in clinical development for the treatment of solid tumors. Preclinical evidence suggests that FTIs can inhibit breast cancers in vitro and in vivo, and a phase II trial of the FTI, R115777, in patients with advanced breast cancer produced encouraging results. Based on prior successful outcomes with agents targeting the estrogen and epidermal growth factor receptor pathways in breast cancer, the FTIs, used alone or more likely with other agents, may be the next exciting targeted therapy in breast cancer.
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Transferasas Alquil y Aril/antagonistas & inhibidores , Antineoplásicos/farmacología , Neoplasias de la Mama/tratamiento farmacológico , Inhibidores Enzimáticos/farmacología , Transferasas Alquil y Aril/metabolismo , Animales , Neoplasias de la Mama/enzimología , Farnesiltransferasa , Femenino , HumanosRESUMEN
The findings presented contribute to quality of life (QOL) research by highlighting the significance of factors affecting the communication by patients with primary-stage squamous cell carcinoma of the head and neck cancer (SCCHN) of their experiences of suffering after treatment to their clinicians. Qualitative research methodology based on open-ended interviews with 18 survivors of American Joint Committee on Cancer primary stage I and II SCCHN were used. The interviews were transcribed verbatim and thematically analyzed. Three important themes emerged: (1). a diminished self (2). fears of addiction, and (3). hopelessness and the loss of meaning in life after SCCHN. The findings indicate that SCCHN patients under-report their experiences mainly due to fear. As a consequence, and perhaps due to a failure on the part of clinicians and patients to adequately address such fears, SCCHN patients may experience greater psychological morbidity, becoming increasingly fatalistic about biomedicine's ability to restore them to health after cancer despite being "cured", or to relieve related symptoms. This qualitative study provides a perspective as to why such under-reporting occurs, thereby potentially enhancing clinician-patient communication and the QOL of SCCHN patients who present with curable disease.
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Carcinoma de Células Escamosas/fisiopatología , Neoplasias de Cabeza y Cuello/fisiopatología , Carcinoma de Células Escamosas/terapia , Femenino , Neoplasias de Cabeza y Cuello/terapia , Humanos , Masculino , Dolor/fisiopatología , Investigación Cualitativa , TexasRESUMEN
The findings presented in this discussion seek to make a contribution to quality of life (QOL) research, by highlighting the import of factors affecting the communication of primary stage head and neck cancer patient's experiences of suffering after treatments by their clinicians. Qualitative research methodology based on open-ended interviews with 18 survivors of American Joint Committee on Cancer (AJCC) Stage I and Stage II, squamous cell carcinoma of the head and neck (SCCHN) were used. The interviews were transcribed verbatim and thematically analysed. In this preliminary analysis, three important themes emerged: (1) a self diminished by cancer; (2) the fear of addiction to pain medications; and (3) hopelessness and the loss of meaning in life after SCCHN. Our present findings indicate that SCCHN patients understand their experiences of cancer and under-report their experiences of suffering mainly because of fear. These include fears of: being further diminished by SCCHN, fears of addiction, and an inability to cope with the additional losses associated with SCCHN. As a consequence, and perhaps, because of a failure the part of clinicians and patients to adequately address these fears, SCCHN patients may also experience greater psychological morbidity, becoming fatalistic about biomedicine's ability to restore them to health after cancer, or related symptoms, including pain, despite being 'cured.' This study provides a perspective on why this under-reporting occurs, thereby potentially enhancing clinician-patient communication and the QOL of SCCHN patients who present with curable disease.
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Carcinoma de Células Escamosas/psicología , Neoplasias de Cabeza y Cuello/psicología , Calidad de Vida , Adulto , Anciano , Anciano de 80 o más Años , Comunicación , Miedo/psicología , Femenino , Humanos , Masculino , Persona de Mediana Edad , Dolor/etiología , Satisfacción del Paciente , Relaciones Médico-Paciente , Grupos de AutoayudaRESUMEN
A prospective randomized study was conducted to determine whether amifostine (Ethyol) reduces the rate of severe esophagitis and hematologic and pulmonary toxicity associated with chemoradiation or improves control of non-small cell lung cancer (NSCLC). Sixty patients with inoperable stage II or III NSCLC were treated with concurrent chemoradiotherapy. Both groups received thoracic radiation therapy (TRT) with 1.2 Gy/fraction, 2 fraction per day, 5 days per week for a total dose 69.6 Gy. All patients received oral etoposide (VP-16), 50 mg Bid, 30 minutes before TRT beginning day 1 for 10 days, repeated on day 29, and cisplatin 50 mg/m(2) intravenously on days 1, 8, 29, and 36. Patients in the study group received amifostine, 500 mg intravenously, twice weekly before chemoradiation (arm 1); patients in the control group received chemoradiation without amifostine (arm 2). Patient and tumor characteristics were distributed equally in both groups. Of the 60 patients enrolled, 53 were evaluable (27 in arm 1, 26 in arm 2) with a median follow-up of 6 months. Median survival times were 26 months for arm 1 and 15 months for arm 2, not statistically significantly different. Morphine intake to reduce severe esophagitis was significantly lower in arm 1 (2 of 27, 7.4%) than arm 2 (8 of 26, 31%; P =.03). Acute pneumonitis was significantly lower in arm 1 (1 of 27, 3.7%) than in arm 2 (6 of 26, 23%; P =.037). Hypotension (20 mm Hg decrease from baseline blood pressure) was significantly more frequent in arm 1 (19 of 27, 70%) than arm 2 (1 of 26, 3.8%; P =.0001). Only 1 patient discontinued treatment because of hypotension. These preliminary results showed that amifostine significantly reduced acute severe esophagitis and pneumonitis. Further observation is required to assess long-term efficacy.
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Amifostina/uso terapéutico , Antineoplásicos Fitogénicos/uso terapéutico , Carcinoma de Pulmón de Células no Pequeñas/radioterapia , Etopósido/uso terapéutico , Neoplasias Pulmonares/radioterapia , Traumatismos por Radiación/prevención & control , Protectores contra Radiación/uso terapéutico , Adulto , Anciano , Carcinoma de Pulmón de Células no Pequeñas/tratamiento farmacológico , Carcinoma de Pulmón de Células no Pequeñas/mortalidad , Terapia Combinada , Esofagitis/etiología , Esofagitis/prevención & control , Femenino , Humanos , Neoplasias Pulmonares/tratamiento farmacológico , Neoplasias Pulmonares/mortalidad , Masculino , Persona de Mediana Edad , Neumonitis por Radiación/prevención & controlRESUMEN
BACKGROUND: Thalidomide has been shown to have antiangiogenic effects in preclinical models as well as a significant antitumor effect in hematologic tumors such as multiple myeloma. The authors performed this Phase II study to determine the activity, toxicity profile, and antiangiogenic effect of thalidomide in patients with locoregionally recurrent or metastatic squamous cell carcinoma of the head and neck. METHODS: Twenty-one patients with recurrent or metastatic squamous cell carcinoma of the head and neck were treated with single-agent thalidomide. All patients had received radiation therapy, and most had undergone surgery (95%) and/or chemotherapy (90%). Thalidomide was initiated at 200 mg;3>daily and increased to a target dose of 1000 mg daily. Patients continued treatment until disease progression, unacceptable toxicity, or death occurred. RESULTS: All 21 patients eventually developed progressive disease. Median time to progression was 50 days (95% confidence interval, 28-70), with median overall survival time of 194 days (95% lower confidence boundary, 151), similar to the progression and survival times reported for this patient group with other agents. Thalidomide was generally well tolerated, with few patients experiencing Grades 3 to 4 toxicities. Serum vascular endothelial growth factor and basic fibroblast growth factor levels increased in six of seven patients, for whom paired serum samples were available and all of whom had progressive disease. CONCLUSIONS: In this heavily pretreated population of patients with advanced squamous cell carcinoma of the head and neck, thalidomide does not appear to have single-agent antitumor activity. Further evaluation of the mechanism of action of thalidomide is indicated. Potentially, future evaluations of thalidomide may be performed in combination with other antiangiogenic or cytotoxic agents in patients with earlier stage disease or in patients with minimal residual disease.
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Inhibidores de la Angiogénesis/farmacología , Carcinoma de Células Escamosas/tratamiento farmacológico , Neoplasias de Cabeza y Cuello/tratamiento farmacológico , Recurrencia Local de Neoplasia/tratamiento farmacológico , Talidomida/farmacología , Administración Oral , Adulto , Anciano , Anciano de 80 o más Años , Inhibidores de la Angiogénesis/efectos adversos , Carcinoma de Células Escamosas/patología , Progresión de la Enfermedad , Femenino , Neoplasias de Cabeza y Cuello/patología , Humanos , Masculino , Persona de Mediana Edad , Análisis de Supervivencia , Talidomida/efectos adversos , Resultado del TratamientoRESUMEN
BACKGROUND: This study was designed to determine if race and age are independent prognostic factors for survival in patients treated for squamous cell carcinoma of the oral cavity and pharynx. METHODS: Retrospective study. RESULTS: Out of 909 patients registered, 815 (90%) were white and 94 (10%) were African-American. The median age was 60 years (range 19-93). The African-American patients had a significantly lower 5 year survival rate of 27.6% (95% CI 19.9-38.3) compared with white patients with a survival rate of 52.0% (95% CI 48.7-55.6) (P < 0.001). The greatest racial disparities in survival were observed in patients under 60 years of age [29.2% (95% CI 19.5-43.6) vs 60.9% (95% CI 56.3-66.0) for African-American and white patients, respectively, P < 0.001], and in African-American men compared with white men [20.2% (95% CI 12.6-30.2) vs 51.0% (95% CI 46.7-53.0), P < 0.001]. A multivariate Cox model, stratified according to stage of disease, indicated that race, age, and type of treatment were statistically significant predictors of survival. After adjusting for race and treatment received, African-American patients had a relative risk of dying of 1.61 (95% CI 1.23-2.10) compared with white patients. All patients 60 years of age and older had a higher risk of dying 1.59 (95% CI 1.31-1.92). Compared with surgical treatment alone, radiotherapy and other treatments were both associated with increased risk of dying with respective relative risks of 1.34 (95% CI 1.01-1.76) and 1.94 (95% CI 1.52-1.48). CONCLUSIONS: African-American patients had poorer survival outcomes, with race and age emerging as significant independent predictors of survival after treatment for oral and pharyngeal cancer, compared with their white counterparts. Primary and secondary prevention programs that target younger patients at high risk might reduce environmental risk factors such as smoking and alcohol consumption, which may play a greater role in the acquired susceptibility for oral and pharyngeal cancer in African-American males.