RESUMO
Colon cancer is the third most incident type of cancer worldwide. One of the most important risk factors for colon cancer development are inflammatory bowel diseases (IBD), thus therapies focusing on IBD treatment have great potential to be used in cancer prevention. Nature has been a source of new therapeutic and preventive agents and the racemic form of the styryl-lactone goniothalamin (GTN) has been shown to be a promising antiproliferative agent, with gastroprotective, antinociceptive and anti-inflammatory effects. As inflammation is a well-known tumor promoter, the major goal of this study was to evaluate the therapeutic and preventive potentials of GTN on chemically induced and spontaneous colitis, as well as the cytotoxic effects of GTN on a human colon tumor cell line (HT-29). GTN treatments inhibited TNBS-induced acute and chronic colitis development in Wistar rats, reducing myeloperoxidase levels and inflammatory cells infiltration in the mucosa. In spontaneous-colitis using IL-10 deficient mice (C57BL/6 background), GTN prevented colitis development through downregulation of TNF-α, upregulation of SIRT-1 and inhibition of proliferation (PCNA index), without signs of toxicity after three months of treatment. In HT-29 cells, treatment with 10µM of GTN induced apoptosis by increasing BAX/BCL2, p-JNK1/JNK1, p-P38/P38 ratios as well as through ROS generation. Caspase 8, 9 and 3 activation also occurred, suggesting caspase-dependent apoptotic pathway, culminating in PARP-1 cleavage. Together with previous data, these results show the importance of GTN as a pro-apoptotic, preventive and therapeutic agent for IBD and highlight its potential as a chemopreventive agent for colon cancer.
Assuntos
Apoptose/efeitos dos fármacos , Colite/tratamento farmacológico , Neoplasias do Colo/tratamento farmacológico , Pironas/farmacologia , Animais , Caspases/biossíntese , Ciclo Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Colite/induzido quimicamente , Colite/patologia , Neoplasias do Colo/patologia , Regulação para Baixo , Células HT29 , Humanos , Interleucina-10/metabolismo , Leucócitos/metabolismo , Masculino , Camundongos Endogâmicos C57BL , Peroxidase/biossíntese , Ratos , Ratos Wistar , Sirtuína 1/metabolismo , Ácido Trinitrobenzenossulfônico/farmacologia , Fator de Necrose Tumoral alfa/metabolismo , Regulação para CimaRESUMO
Riboflavin (vitamin B2) is a precursor for coenzymes involved in energy production, biosynthesis, detoxification, and electron scavenging. Previously, we demonstrated that irradiated riboflavin (IR) has potential antitumoral effects against human leukemia cells (HL60), human prostate cancer cells (PC3), and mouse melanoma cells (B16F10) through a common mechanism that leads to apoptosis. Hence, we here investigated the effect of IR on 786-O cells, a known model cell line for clear cell renal cell carcinoma (CCRCC), which is characterized by high-risk metastasis and chemotherapy resistance. IR also induced cell death in 786-O cells by apoptosis, which was not prevented by antioxidant agents. IR treatment was characterized by downregulation of Fas ligand (TNF superfamily, member 6)/Fas (TNF receptor superfamily member 6) (FasL/Fas) and tumor necrosis factor receptor superfamily, member 1a (TNFR1)/TNFRSF1A-associated via death domain (TRADD)/TNF receptor-associated factor 2 (TRAF) signaling pathways (the extrinsic apoptosis pathway), while the intrinsic apoptotic pathway was upregulated, as observed by an elevated Bcl-2 associated x protein/B-cell CLL/lymphoma 2 (Bax/Bcl-2) ratio, reduced cellular inhibitor of apoptosis 1 (c-IAP1) expression, and increased expression of apoptosis-inducing factor (AIF). The observed cell death was caspase-dependent as proven by caspase 3 activation and poly(ADP-ribose) polymerase-1 (PARP) cleavage. IR-induced cell death was also associated with downregulation of v-src sarcoma (Schmidt-Ruppin A-2) viral oncogene homologue (avian)/protein serine/threonine kinase B/extracellular signal-regulated protein kinase 1/2 (Src/AKT/ERK1/2) pathway and activation of p38 MAP kinase (p38) and Jun-amino-terminal kinase (JNK). Interestingly, IR treatment leads to inhibition of matrix metalloproteinase-2 (MMP-2) activity and reduced expression of renal cancer aggressiveness markers caveolin-1, low molecular weight phosphotyrosine protein phosphatase (LMWPTP), and kinase insert domain receptor (a type III receptor tyrosine kinase) (VEGFR-2). Together, these results show the potential of IR for treating cancer.
Assuntos
Apoptose/efeitos dos fármacos , Carcinoma de Células Renais/tratamento farmacológico , Riboflavina/administração & dosagem , Transdução de Sinais/efeitos dos fármacos , Animais , Fator de Indução de Apoptose/biossíntese , Carcinoma de Células Renais/genética , Carcinoma de Células Renais/patologia , Caspases/biossíntese , Linhagem Celular Tumoral , Proteína Ligante Fas/biossíntese , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Humanos , Camundongos , Peptídeos e Proteínas Associados a Receptores de Fatores de Necrose Tumoral/biossíntese , Proteínas Quinases p38 Ativadas por Mitógeno/biossínteseRESUMO
Pancreatic cancer ranks fourth among cancer-related causes of death in North America. Minimal progress has been made in the diagnosis and treatment of patients with late-stage tumors. Moreover, pancreatic cancer aggressiveness is closely related to high levels of pro-survival mediators, which can ultimately lead to rapid disease progression, resistance and metastasis. The main goal of this study was to define the mechanisms by which calix[6]arene, but not other calixarenes, efficiently decreases the aggressiveness of a drug resistant human pancreas carcinoma cell line (Panc-1). Calix[6]arene was more potent in reducing Panc-1 cell viability than gemcitabine and 5-fluorouracil. In relation to the underlying mechanisms of cytotoxic effects, it led to cell cycle arrest in the G0/G1 phase through downregulation of PIM1, CDK2, CDK4 and retinoblastoma proteins. Importantly, calix[6]arene abolished signal transduction of Mer and AXL tyrosine kinase receptors, both of which are usually overexpressed in pancreatic cancer. Accordingly, inhibition of PI3K and mTOR was also observed, and these proteins are positively modulated by Mer and AXL. Despite decreasing the phosphorylation of AKT at Thr308, calix[6]arene caused an increase in phosphorylation at Ser473. These findings in conjunction with increased BiP and IRE1-α provide a molecular basis explaining the capacity of calix[6]arene to trigger endoplasmic reticulum stress and autophagic cell death. Our findings highlight calix[6]arene as a potential candidate for overcoming pancreatic cancer aggressiveness. Importantly, we provide evidence that calix[6]arene affects a broad array of key targets that are usually dysfunctional in pancreatic cancer, a highly desirable characteristic for chemotherapeutics.
Assuntos
Apoptose/efeitos dos fármacos , Autofagia/efeitos dos fármacos , Calixarenos/farmacologia , Regulação para Baixo/efeitos dos fármacos , Estresse do Retículo Endoplasmático/efeitos dos fármacos , Neoplasias Pancreáticas/patologia , Fenóis/farmacologia , Receptores Proteína Tirosina Quinases/metabolismo , Calixarenos/química , Pontos de Checagem do Ciclo Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Cloroquina/farmacologia , Humanos , Invasividade Neoplásica , Neoplasias Pancreáticas/enzimologia , Neoplasias Pancreáticas/ultraestrutura , Fenóis/química , Fosfatidilinositol 3-Quinases/metabolismo , Transdução de Sinais/efeitos dos fármacos , Serina-Treonina Quinases TOR/metabolismoRESUMO
Glioblastoma is the most aggressive primary brain tumor. Surgical resection, radiotherapy and temozolomide (TMZ), an alkylating agent, is the standard of care. Glioma cells may synthetize the antioxidant glutathione by importing cystine through a cystine/glutamate antiporter, which is inhibited by sulfasalazine (SAS). C6 rat glioma cells are largely used in in vitro and in vivo models for developing new glioblastoma treatment strategies. We treated C6 cells with 25µM TMZ and/or 0.25mM or 0.5mM SAS for 1, 3 or 5days and evaluated viability, apoptosis, total glutathione levels and metalloproteinase MMP2 and MMP9 activities. TMZ treatment slightly reduced cell viability by 9.5% compared with vehicle treatment (0.1% dimethyl sulfoxide) only after 5days. In addition, TMZ did not modify apoptosis, glutathione content or MMP2/MMP9 activities. The 0.25mM SAS treatment reduced cell viability by 31.1% and 19.4% after the first and third days, respectively. This effect was not sustained after the fifth day of treatment. In contrast, 0.5mM SAS caused a reduction in cell viability by nearly 100%, total glutathione depletion and apoptosis induction. Moreover, the effect of 0.5mM SAS was greater than that of TMZ in terms of cell viability reduction, total glutathione depletion and apoptosis induction. MMP9 activity was reduced by 40% after 5days of 25µM TMZ and 0.5mM SAS co-administration. Considering previous data from our group, we verified that the cellular viability results differed between rat and human cells; C6 cells were more vulnerable to 0.5mM SAS than human A172 and T98G glioblastoma lineages. We propose that C6 cells may not be appropriate for studying human glioblastoma and that the results obtained using these cells should be interpreted with caution.
Assuntos
Antineoplásicos/farmacologia , Sulfassalazina/farmacologia , Animais , Apoptose/efeitos dos fármacos , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Dacarbazina/análogos & derivados , Dacarbazina/farmacologia , Glioma , Glutationa/metabolismo , Metaloproteinase 2 da Matriz/metabolismo , Metaloproteinase 9 da Matriz/metabolismo , Ratos , TemozolomidaRESUMO
BACKGROUND: Low-risk patients suffering from prostate cancer (PCa) are currently placed under active surveillance rather than undergoing radical prostatectomy. However, clear parameters for selecting the right patient for each strategy are not available, and new biomarkers and treatment modalities are needed. Low-molecular-weight protein tyrosine phosphatase (LMWPTP) could present such a target. OBJECTIVE: To correlate expression levels of LMWPTP in primary PCa to clinical outcome, and determine the role of LMWPTP in prostate tumor cell biology. DESIGN, SETTING, AND PARTICIPANTS: Acid phosphatase 1, soluble (ACP1) expression was analyzed on microarray data sets, which were subsequently used in Ingenuity Pathway Analysis. Immunohistochemistry was performed on a tissue microarray containing material of 481 PCa patients whose clinicopathologic data were recorded. PCa cell line models were used to investigate the role of LMWPTP in cell proliferation, migration, adhesion, and anoikis resistance. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: The association between LMWPTP expression and clinical and pathologic outcomes was calculated using chi-square correlations and multivariable Cox regression analysis. Functional consequences of LMWPTP overexpression or downregulation were determined using migration and adhesion assays, confocal microscopy, Western blotting, and proliferation assays. RESULTS AND LIMITATIONS: LMWPTP expression was significantly increased in human PCa and correlated with earlier recurrence of disease (hazard ratio [HR]:1.99; p<0.001) and reduced patient survival (HR: 1.53; p=0.04). Unbiased Ingenuity analysis comparing cancer and normal prostate suggests migratory propensities in PCa. Indeed, overexpression of LMWPTP increases PCa cell migration, anoikis resistance, and reduces activation of focal adhesion kinase/paxillin, corresponding to decreased adherence. CONCLUSIONS: Overexpression of LMWPTP in PCa confers a malignant phenotype with worse clinical outcome. Prospective follow-up should determine the clinical potential of LMWPTP overexpression. PATIENT SUMMARY: These findings implicate low-molecular-weight protein tyrosine phosphatase as a novel oncogene in prostate cancer and could offer the possibility of using this protein as biomarker or target for treatment of this disease.
Assuntos
Biomarcadores Tumorais/metabolismo , Movimento Celular , Neoplasias da Próstata/enzimologia , Proteínas Tirosina Fosfatases/metabolismo , Proteínas Proto-Oncogênicas/metabolismo , Idoso , Anoikis , Biomarcadores Tumorais/genética , Adesão Celular , Linhagem Celular Tumoral , Proliferação de Células , Distribuição de Qui-Quadrado , Quinase 1 de Adesão Focal/metabolismo , Humanos , Estimativa de Kaplan-Meier , Masculino , Pessoa de Meia-Idade , Peso Molecular , Análise Multivariada , Metástase Neoplásica , Recidiva Local de Neoplasia , Seleção de Pacientes , Paxilina/metabolismo , Valor Preditivo dos Testes , Prognóstico , Modelos de Riscos Proporcionais , Prostatectomia , Neoplasias da Próstata/genética , Neoplasias da Próstata/patologia , Neoplasias da Próstata/terapia , Proteínas Tirosina Fosfatases/genética , Proteínas Proto-Oncogênicas/genética , Medição de Risco , Fatores de Risco , Fatores de Tempo , Análise Serial de Tecidos , Transfecção , Regulação para Cima , Conduta ExpectanteRESUMO
Natural products containing the α,ß-unsaturated δ-lactone skeleton have been shown to possess a variety of biological activities. The natural product (-)-tarchonanthuslactone (1) possessing this privileged scaffold is a popular synthetic target, but its biological activity remains underexplored. Herein, the total syntheses of dihydropyran-2-ones modeled on the structure of 1 were undertaken. These compounds were obtained in overall yields of 17-21 % based on the Keck asymmetric allylation reaction and were evaluated inâ vitro against eight different cultured human tumor cell lines. We further conducted initial investigation into the mechanism of action of selected analogues. Dihydropyran-2-one 8 [(S,E)-(6-oxo-3,6-dihydro-2H-pyran-2-yl)methyl 3-(3,4-dihydroxyphenyl)acrylate], a simplified analogue of (-)-tarchonanthuslactone (1) bearing an additional electrophilic site and a catechol system, was the most cytotoxic and selective compound against six of the eight cancer cell lines analyzed, including the pancreatic cancer cell line. Preliminary studies on the mechanism of action of compound 8 on pancreatic cancer demonstrated that apoptotic cell death takes place mediated by an increase in the level of reactive oxygen species. It appears as though compound 8, possessing two Michael acceptors and a catechol system, may be a promising scaffold for the selective killing of cancer cells, and thus, it deserves further investigation to determine its potential for cancer therapy.
Assuntos
Antineoplásicos Fitogênicos/farmacologia , Produtos Biológicos/farmacologia , Desenho de Fármacos , Pironas/farmacologia , Antineoplásicos Fitogênicos/síntese química , Antineoplásicos Fitogênicos/química , Produtos Biológicos/síntese química , Produtos Biológicos/química , Proliferação de Células/efeitos dos fármacos , Relação Dose-Resposta a Droga , Ensaios de Seleção de Medicamentos Antitumorais , Humanos , Estrutura Molecular , Pironas/síntese química , Pironas/química , Estereoisomerismo , Relação Estrutura-Atividade , Células Tumorais CultivadasRESUMO
Reversible phosphorylation of proteins, performed by kinases and phosphatases, is the major post translational protein modification in eukaryotic cells. This intracellular event represents a critical regulatory mechanism of several signaling pathways and can be related to a vast array of diseases, including cancer. Cancer research has produced increasing evidence that kinase and phosphatase activity can be compromised by mutations and also by miRNA silencing, performed by small non-coding and endogenously produced RNA molecules that lead to translational repression. miRNAs are believed to target about one-third of human mRNAs while a single miRNA may target about 200 transcripts simultaneously. Regulation of the phosphorylation balance by miRNAs has been a topic of intense research over the last years, spanning topics going as far as cancer aggressiveness and chemotherapy resistance. By addressing recent studies that have shown miRNA expression patterns as phenotypic signatures of cancers and how miRNA influence cellular processes such as apoptosis, cell cycle control, angiogenesis, inflammation and DNA repair, we discuss how kinases, phosphatases and miRNAs cooperatively act in cancer biology.
Assuntos
MicroRNAs , Neoplasias/enzimologia , Neoplasias/genética , Monoéster Fosfórico Hidrolases/metabolismo , Proteínas Quinases/metabolismo , Regulação Neoplásica da Expressão Gênica , Humanos , MicroRNAs/genética , MicroRNAs/metabolismo , Monoéster Fosfórico Hidrolases/genética , Proteínas Quinases/genética , Processamento de Proteína Pós-Traducional , Estabilidade de RNARESUMO
In this study, a novel concise series of molecules based on the structure of goniothalamin (1) was synthesized and evaluated against a highly metastatic human pancreatic cancer cell line (Panc-1). Among them, derivative 8 displayed a low IC50 value (2.7 µM) and its concentration for decreasing colony formation was 20-fold lower than goniothalamin (1). Both compounds reduced the levels of the receptor tyrosine kinase (AXL) and cyclin D1 which are known to be overexpressed in pancreatic cancer cells. Importantly, despite the fact that goniothalamin (1) and derivative 8 caused pancreatic cancer cell cycle arrest and cell death, only derivative 8 was able to downregulate pro-survival and proliferation pathways mediated by mitogen activated protein kinase ERK1/2. Another interesting finding was that Panc-1 cells treated with derivative 8 displayed a strong decrease in the transcription factor (c-Myc), hypoxia-inducible factor-1α (HIF-1α) and vascular endothelial growth factor (VEGF) protein levels. Notably, the molecular effects caused by derivative 8 might not be related to ROS generation, since no significant production of ROS was observed in low concentrations of this compound (from 1.5 up to 3 µM). Therefore, the downregulation of important mediators of pancreatic cancer aggressiveness by derivative 8 reveals its great potential for the development of new chemotherapeutic agents for pancreatic cancer treatment.
Assuntos
Compostos Aza/química , Regulação para Baixo/efeitos dos fármacos , Neoplasias Pancreáticas/patologia , Pironas/farmacologia , Transdução de Sinais/efeitos dos fármacos , Acilação , Animais , Linhagem Celular , Neoplasias Pancreáticas/metabolismo , Pironas/químicaRESUMO
The aim of this work was to study the interaction between the local anesthetic benzocaine and p-sulfonic acid calix[n]arenes using NMR and theoretical calculations and to assess the effects of complexation on cytotoxicity of benzocaine. The architectures of the complexes were proposed according to (1) H NMR data (Job plot, binding constants, and ROESY) indicating details on the insertion of benzocaine in the cavity of the calix[n]arenes. The proposed inclusion compounds were optimized using the PM3 semiempirical method, and the electronic plus nuclear repulsion energy contributions were performed at the DFT level using the PBE exchange/correlation functional and the 6-311G(d) basis set. The remarkable agreement between experimental and theoretical approaches adds support to their use in the structural characterization of the inclusion complexes. In vitro cytotoxic tests showed that complexation intensifies the intrinsic toxicity of benzocaine, possibly by increasing the water solubility of the anesthetic and favoring its partitioning inside of biomembranes.
Assuntos
Benzocaína/química , Calixarenos/química , Espectroscopia de Ressonância Magnética , Animais , Calixarenos/toxicidade , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Camundongos , Modelos Teóricos , Conformação Molecular , Ácidos Sulfônicos/químicaRESUMO
Because of its severe side effects and variable efficacy, the current treatment for Chagas disease is unsatisfactory. Natural compounds are good alternative chemotherapeutic agents for the treatment of this infection. Recently, our group reported the antiproliferative activity and morphological alterations in epimastigotes and intracellular amastigotes of Trypanosoma cruzi treated with eupomatenoid-5, a neolignan isolated from leaves of Piper regnellii var. pallescens. Here, we demonstrate that eupomatenoid-5 exhibited activity against trypomastigotes, the infective form of T. cruzi (EC50 40.5 µM), leading to ultrastructural alteration and lipoperoxidation in the cell membrane. Additionally, eupomatenoid-5 induced depolarization of the mitochondrial membrane, lipoperoxidation and increased G6PD activity in epimastigotes of T. cruzi. These findings support the possibility that different mechanisms may be targeted, according to the form of the parasite, and that the plasma membrane and mitochondria are the structures that are most affected in trypomastigotes and epimastigotes, respectively. Thus, the trypanocidal action of eupomatenoid-5 may be associated with mitochondrial dysfunction and oxidative damage, which can trigger destructive effects on biological molecules of T. cruzi, leading to parasite death.
Assuntos
Benzofuranos/farmacologia , Mitocôndrias/metabolismo , Fenóis/farmacologia , Piper/química , Extratos Vegetais/química , Tripanossomicidas/farmacologia , Trypanosoma cruzi/efeitos dos fármacos , Benzofuranos/química , Benzofuranos/isolamento & purificação , Doença de Chagas/tratamento farmacológico , Doença de Chagas/parasitologia , Glucose-6-Fosfato/metabolismo , Humanos , Peróxido de Hidrogênio/metabolismo , Lignanas/química , Lignanas/isolamento & purificação , Lignanas/farmacologia , Peroxidação de Lipídeos/efeitos dos fármacos , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Mitocôndrias/efeitos dos fármacos , Membranas Mitocondriais/efeitos dos fármacos , Membranas Mitocondriais/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Fenóis/química , Fenóis/isolamento & purificação , Fosfogluconato Desidrogenase/efeitos dos fármacos , Fosfogluconato Desidrogenase/metabolismo , Folhas de Planta/química , Tripanossomicidas/química , Tripanossomicidas/isolamento & purificação , Trypanosoma cruzi/metabolismo , Trypanosoma cruzi/ultraestruturaRESUMO
Parthenolide previously isolated from Tanacetum vulgare was tested for its in vitro combinatory effect with benznidazole against Trypanosoma cruzi. Parthenolide showed a strong synergistic activity against epimastigote forms, reducing 23-fold the concentration of benznidazole necessary to inhibit 50% of cell growth (IC(50) of 1.6 to 0.07 µg/ml) when in combination with parthenolide. In addition, an additive effect against trypomastigote forms (FIC 1.06), followed by an antagonistic effect on the cytotoxicity (FIC 2.36), was observed for the combination of both drugs. Parthenolide induced morphological alterations in the body shape of trypomastigote forms, causing rounding and shortening of the parasite and loss of integrity of the plasma membrane, as previously described by other workers.