RESUMO
BACKGROUND: The aim of this study was to determine the apoptotic activity of methanol extract of Ashwagandha (MEAG) and in human head and neck squamous cell carcinoma (HNSCC) cells and to investigate the underlying mechanisms. METHODS: We investigated the effects of MEAG on programmed cell death in HNSCC cells using a Live/Dead assay, detection of nuclear morphologic changes, Mitotracker, siRNA knockdown, and RT-PCR. RESULTS: Treatment with MEAG showed dose-dependent growth-inhibitory activity that attribute to caspase-dependent apoptosis. Loss of mitochondrial membrane potential, release of cytochrome c, and activation of caspase 9 suggested that MEAG leads to activation of mitochondria-mediated apoptosis. MEAG selectively upregulated the expression of Bim protein at the transcriptional level and induced the translocation of Bim into the mitochondria. Knockdown of Bim by siRNA partially blocked MEAG-mediated apoptosis. MEAG also caused an increase in truncated Bid (t-Bid), cleaved caspase-8, and death receptor 5 (DR5). Interestingly, withaferin A (WA), a bioactive component of MEAG, clearly induced apoptosis accompanied by upregulation of Bim, t-Bid, caspase-8, and DR5 similar to the effects of MEAG. CONCLUSIONS: These suggest that MEAG and WA may be potential natural materials for the treatment of HNSCC.
Assuntos
Carcinoma de Células Escamosas/tratamento farmacológico , Neoplasias de Cabeça e Pescoço/tratamento farmacológico , Extratos Vegetais/farmacologia , Antineoplásicos/farmacologia , Apoptose/efeitos dos fármacos , Proteínas Reguladoras de Apoptose/metabolismo , Proteína 11 Semelhante a Bcl-2/deficiência , Proteína 11 Semelhante a Bcl-2/genética , Proteína 11 Semelhante a Bcl-2/metabolismo , Carcinoma de Células Escamosas/metabolismo , Carcinoma de Células Escamosas/patologia , Caspase 8/metabolismo , Caspase 9/efeitos dos fármacos , Caspase 9/metabolismo , Linhagem Celular Tumoral , Citocromos c/metabolismo , Ativação Enzimática/efeitos dos fármacos , Neoplasias de Cabeça e Pescoço/metabolismo , Neoplasias de Cabeça e Pescoço/patologia , Humanos , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Membranas Mitocondriais/efeitos dos fármacos , Neoplasias Bucais/tratamento farmacológico , Receptores do Ligante Indutor de Apoptose Relacionado a TNF/metabolismo , Carcinoma de Células Escamosas de Cabeça e Pescoço , Regulação para Cima , Vitanolídeos/farmacologiaRESUMO
To date, many different chemotherapeutic agents have been widely used as common treatments for oral cancers. However, their therapeutic effects have been disappointing, and these agents may have unwanted side effects. Among the many regulatory factors, overexpression of pro-survival Bcl-2 family members may promote resistance to chemotherapeutic drugs in many tumors. The BH3 domain-only proteins effectively antagonize their apoptotic activities. Therefore, there is substantial interest in developing chemotherapeutic drugs that directly target pro-survival Bcl-2 proteins by mimicking the BH3 domain and unleashing pro-apoptotic molecules in tumor cells. Among the numerous available small molecule BH3 mimetics, ABT-737, a potent small molecule that binds to Bcl-2/Bcl-xL with high affinity, has anti-tumor activity in a wide variety of cancer cells. However, the effects of ABT-737 on human oral cancers and the underlying molecular mechanisms have not previously been elucidated. In the present study, we observed that inactivation of the ERK1/2 signaling pathway using ABT-737 dramatically increased the expression of pro-apoptotic protein Bim via transcriptional and/or posttranslational regulation, in a cell type-dependent manner, inducing mitochondria-mediated apoptosis of human oral cancer cells. To the best of our knowledge, this is the first demonstration of the antitumor effects of ABT-737 on human oral cancers.
Assuntos
Antineoplásicos/farmacologia , Compostos de Bifenilo/farmacologia , Carcinoma Mucoepidermoide/tratamento farmacológico , Carcinoma de Células Escamosas/tratamento farmacológico , Neoplasias Bucais/tratamento farmacológico , Nitrofenóis/farmacologia , Sulfonamidas/farmacologia , Apoptose/efeitos dos fármacos , Proteínas Reguladoras de Apoptose/genética , Proteínas Reguladoras de Apoptose/metabolismo , Proteína Agonista de Morte Celular de Domínio Interatuante com BH3/metabolismo , Proteína 11 Semelhante a Bcl-2 , Biomimética , Linhagem Celular Tumoral , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Humanos , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Proteínas de Membrana/genética , Proteínas de Membrana/metabolismo , Terapia de Alvo Molecular , Piperazinas/farmacologia , Proteínas Proto-Oncogênicas/genética , Proteínas Proto-Oncogênicas/metabolismo , Proteínas Proto-Oncogênicas c-bcl-2/antagonistas & inibidoresRESUMO
This study evaluated bacterial etiology and antibiotic susceptibility in patients diagnosed with community-acquired perforated appendicitis over a 12-year-period. We retrospectively reviewed records of adult patients diagnosed with perforated appendicitis at an 800-bed teaching hospital between January 2000 and December 2011. In total, 415 culture-positive perforated appendicitis cases were analyzed. Escherichia coli was the most common pathogen (277/415, 66.7%), followed by Streptococcus species (61/415, 14.7%). The susceptibility of E. coli to ampicillin, piperacillin/tazobactam, ceftriaxone, cefepime, amikacin, gentamicin, and imipenem was 35.1%, 97.1%, 97.0%, 98.2%, 98.9%, 81.8%, and 100%, respectively. The overall susceptibility of E. coli to quinolones (ciprofloxacin or levofloxacin) was 78.7%. During the study period, univariate logistic regression analysis showed a significant decrease in E. coli susceptibility to quinolones (ORâ=â0.91, 95% CI 0.84-0.99, Pâ=â0.040). We therefore do not recommend quinolones as empirical therapy for community-acquired perforated appendicitis.