RESUMO
The activation of the nuclear factor-κB (NF-κB) pathway has been associated with the development and progression of colorectal cancer (CRC). Parthenolide (PTL), a well-known inhibitor of the NF-κB pathway, has emerged as an alternative treatment. However, whether PTL activity is tumor cell-specific and dependent on the mutational background has not been defined. This study investigated the antitumor role of PTL after tumor necrosis factor-α (TNF-α) stimulation in various CRC cell lines with different mutational statuses of TP53. We observed that CRC cells displayed different patterns of basal p-IκBα levels; PTL reduced cell viability according to p-IκBα levels and p-IκBα levels varied among the cell lines according to the time of TNF-α stimulation. High concentrations of PTL reduced more effectively p-IκBα levels than low doses of PTL. However, PTL increased total IκBα levels in Caco-2 and HT-29 cells. In addition, PTL treatment downregulated p-p65 levels in HT-29 and HCT-116 cells stimulated by TNF-α in a dose-dependent manner. Moreover, PTL induced cell death via apoptosis and reduced the proliferation rate of TNF-α-treated HT-29 cells. Finally, PTL downregulated the messenger RNA levels of interleukin-1ß, a downstream cytokine of NF-κB, reverted the E-cadherin-mediated disorganization of cell-cell contacts, and decreased the invasion of HT-29 cells. Together, these results suggest a differential antitumoral activity of PTL on CRC cells with different mutational statuses of TP53, modulating cell death, survival, and proliferation underlying the NF-κB pathway TNF-α-induced. Therefore, PTL has emerged as a potential treatment for CRC in an inflammatory NF-κB-dependent manner.
Assuntos
Neoplasias Colorretais , NF-kappa B , Humanos , NF-kappa B/metabolismo , Inibidor de NF-kappaB alfa/metabolismo , Fator de Necrose Tumoral alfa/metabolismo , Regulação para Baixo , Adesão Celular , Células CACO-2 , Apoptose , Proliferação de Células , Neoplasias Colorretais/tratamento farmacológicoRESUMO
Radiotherapy is one of the most common modalities for the treatment of a wide range of tumors, including colorectal cancer (CRC); however, radioresistance of cancer cells remains a major limitation for this treatment. Following radiotherapy, the activities of various cellular mechanisms and cell signaling pathways are altered, resulting in the development of radioresistance, which leads to therapeutic failure and poor prognosis in patients with cancer. Furthermore, even though several inhibitors have been developed to target tumor resistance, these molecules can induce side effects in nontumor cells due to low specificity and efficiency. However, the role of these mechanisms in CRC has not been extensively studied. This review discusses recent studies regarding the relationship between radioresistance and the alterations in a series of cellular mechanisms and cell signaling pathways that lead to therapeutic failure and tumor recurrence. Our review also presents recent advances in the in vitro/in vivo study models aimed at investigating the radioresistance mechanism in CRC. Furthermore, it provides a relevant biochemical basis in theory, which can be useful to improve radiotherapy sensitivity and prolong patient survival.
Assuntos
Neoplasias Colorretais , Transdução de Sinais , Humanos , Tolerância a Radiação , Neoplasias Colorretais/metabolismo , Linhagem Celular TumoralRESUMO
Transforming growth factor-ß (TGF-ß) plays a dual role acting as tumor promoter or suppressor. Along with cyclooxygenase-2 (COX-2) and oncogenic Ras, this multifunctional cytokine is deregulated in colorectal cancer. Despite their individual abilities to promote tumor growth and invasion, the mechanisms of cross regulation between these pathways is still unclear. Here, we investigate the effects of TGF-ß, Ras oncogene and COX-2 in the colorectal cancer context. We used colon adenocarcinoma cell line HT-29 and Ras-transformed IEC-6 cells, both treated with prostaglandin E2 (PGE2 ), TGF-ß or a combined treatment with these agents. We demonstrated that PGE2 alters the subcellular localization of E-cadherin and ß-catenin and enhanced the tumorigenic potential in HT-29 cells. This effect was inhibited by TGF-ß, indicating a tumor suppressor role. Conversely, in Ras-transformed IEC-6 cells, TGF-ß induced COX-2 expression and increased invasiveness, acting as a tumor promoter. In IEC-6 Ras-transformed cells, TGF-ß increased nuclear ß-catenin and Wnt/ß-catenin activation, opposite to what was seen in the PGE2 and TGF-ß joint treatment in HT-29 cells. Together, our findings show that TGF-ß increases COX-2 levels and induces invasiveness cooperating with Ras in a Wnt/ß-catenin activation-dependent manner. This shows TGF-ß dual regulation over COX-2/PGE2 tumor promotion depending on the H-Ras and Wnt/ß-catenin pathways activation status in intestinal cancer cells.
Assuntos
Carcinogênese/metabolismo , Carcinogênese/patologia , Neoplasias Colorretais/metabolismo , Ciclo-Oxigenase 2/metabolismo , Dinoprostona/metabolismo , Proteínas Proto-Oncogênicas p21(ras)/metabolismo , Fator de Crescimento Transformador beta/metabolismo , Via de Sinalização Wnt , Caderinas/metabolismo , Movimento Celular , Proliferação de Células , Neoplasias Colorretais/patologia , Células HT29 , Humanos , Invasividade Neoplásica , Fatores de Transcrição TCF/metabolismo , Transcrição Gênica , beta Catenina/metabolismoRESUMO
Changes in protein levels in different components of the apical junctional complex occur in colorectal cancer (CRC). Claudin3 is one of the main constituents of tight junctions, and its overexpression can increase the paracellular flux of macromolecules, as well as the malignant potential of CRC cells. The aim of this study was to investigate the molecular mechanisms involved in the regulation of claudin3 and its prognostic value in CRC. In silico evaluation in each of the CRC consensus molecular subtypes (CMSs) revealed that high expression levels of CLDN3 (gene encoding claudin3) in CMS2 and CMS3 worsened the patients' longterm survival, whereas a decrease in claudin3 levels concomitant with a reduction in phosphorylation levels of epidermal growth factor receptor (EGFR) and insulinlike growth factor 1 receptor (IGF1R) could be achieved by inhibiting Nglycan biosynthesis in CRC cells. We also observed that specific inactivation of these receptor tyrosine kinases (RTKs) led to a decrease in claudin3 levels, and this regulation seems to be mediated by phospholipase C (PLC) and signal transducer and activator of transcription 3 (STAT3) in CRC cells. RTKs are modulated by their Nlinked glycans, and inhibition of Nglycan biosynthesis decreased the claudin3 levels; therefore, we evaluated the correlation between Nglycogenes and CLDN3 expression levels in each of the CRC molecular subtypes. The CMS1 (MSI immune) subtype concomitantly exhibited low expression levels of CLDN3 and Nglycogenes (MGAT5, ST6GAL1, and B3GNT8), whereas CMS2 (canonical) exhibited high gene expression levels of CLDN3 and Nglycogenes (ST6GAL1 and B3GNT8). A robust positive correlation was also observed between CLDN3 and B3GNT8 expression levels in all CMSs. These results support the hypothesis of a mechanism integrating RTK signaling and Nglycosylation for the regulation of claudin3 levels in CRC, and they suggest that CLDN3 expression can be used to predict the prognosis of patients identified as CMS2 or CMS3.
Assuntos
Antígenos CD/genética , Claudina-3/genética , Neoplasias Colorretais/genética , N-Acetilglucosaminiltransferases/genética , Sialiltransferases/genética , Neoplasias Colorretais/patologia , Intervalo Livre de Doença , Receptores ErbB/genética , Feminino , Regulação Neoplásica da Expressão Gênica/genética , Glicosilação , Humanos , Masculino , Pessoa de Meia-Idade , Prognóstico , Receptor IGF Tipo 1/genética , Fator de Transcrição STAT3/genética , Transdução de Sinais/genéticaRESUMO
Aim: Colon cancer (CC) is the second cause of cancer death worldwide. The use of nanoparticles for drug delivery has been increasing in cancer clinical trials over recent years. Materials & methods: We evaluated cytotoxicity of citrate-capped gold nanoparticles (GNPs) and the role they play on cell-cell adhesion. We also used GNP for delivery of cetuximab into different CC cell lines. Results: CC cells with well-formed tight junctions impair GNP uptake. Noncytotoxic concentration of GNP increases paracellular permeability in Caco-2 cells in a reversible way, concomitantly to tight junctions proteins CLDN1 and ZO-1 redistribution. GNP functionalized with cetuximab increases death of invasive HCT-116 CC cells. Conclusion: GNP can be used for drug delivery and can improve efficiency of CC therapy.
Assuntos
Cetuximab/farmacologia , Nanopartículas Metálicas/química , Células CACO-2 , Sobrevivência Celular/efeitos dos fármacos , Imunofluorescência , Ouro , Células HCT116 , Células HT29 , Humanos , Nanopartículas Metálicas/ultraestrutura , Microscopia Eletrônica de Transmissão , Junções Íntimas/efeitos dos fármacos , Junções Íntimas/metabolismo , Junções Íntimas/ultraestruturaRESUMO
Dysfunctional p53 formation and activity can result from aberrant expression and subcellular localization of distinct p53 isoforms or aggregates. Endometrial carcinoma (EC) is a cancer type in which p53 status is correlated with prognosis, and TP53 mutations are a frequent genetic modification. Here we aimed to evaluate the expression patterns of different p53 isoforms and their contributions to the formation and subcellular localization of p53 amyloid aggregates in both EC and endometrial nontumor cell lines. We found that full-length (fl) p53 and a truncated p53 isoform, Δ40p53, resulting from alternative splicing of exon 2 or alternative initiation of translation at ATG-40, are the predominantly expressed p53 variants in EC cells. However, Δ40p53 was the major p53 isoform in endometrial nontumor cells. Immunofluorescence assays revealed that Δ40p53 is mainly localized to cytoplasmic punctate structures of EC cells, resembling solid-phase structures similar to those found in neurodegenerative pathologies. Using light-scattering kinetics, CD, and transmission EM, we noted that the p53 N-terminal transactivation domain significantly reduces aggregation of the WT p53 DNA-binding domain, confirming the higher aggregation tendency of Δ40p53, which lacks this domain. This is the first report of cytoplasmic Δ40p53 in EC cells being a major component of amyloid aggregates. The differential aggregation properties of p53 isoforms in EC cells may open up new avenues in the development of therapeutic strategies that preferentially target specific p53 isoforms to prevent p53 amyloid aggregate formation.
Assuntos
Amiloide/química , Amiloidose , Neoplasias do Endométrio/patologia , Agregados Proteicos , Ativação Transcricional , Proteína Supressora de Tumor p53/química , Proteína Supressora de Tumor p53/metabolismo , Processamento Alternativo , Proteínas Amiloidogênicas/genética , Proteínas Amiloidogênicas/metabolismo , Neoplasias do Endométrio/genética , Neoplasias do Endométrio/metabolismo , Feminino , Humanos , Conformação Proteica , Isoformas de Proteínas , Células Tumorais Cultivadas , Proteína Supressora de Tumor p53/genéticaRESUMO
Annexin A2 (ANXA2) is upregulated in several malignancies, including colorectal cancer (CRC). However, there is little knowledge on the molecular mechanisms involved to its upregulation. The aim of this study was to identify the mechanism through which ANXA2 overexpression leads to CRC progression and evaluate its potential prognostic value. We used human CRC samples to analyse the correlation between ANXA2 levels and tumour staging. ANXA2 expression was increased in CRC tissues compared to normal colon tissues. In addition, we observe increased ANXA2 levels in stage IV tumours and metastasis, when compared to stage I-III. Whereas E-cadherin, an epithelial marker, decreased in stage II-IV and increased in metastasis. We've also shown that TGF-ß, a classic EMT inductor, caused upregulation of ANXA2, and internalization of both E-cadherin and ANXA2 in CRC cells. ANXA2 silencing hindered TGF-ß-induced invasiveness, and inhibitors of the Src/ANXA2/STAT3 pathway reversed the EMT. In silico analysis confirmed overexpression of ANXA2 and association to the consensus moleculars subtypes (CMS) with the worst prognosis. Therefore, ANXA2 overexpression play a pivotal role in CRC invasiveness through Src/ANXA2/STAT3 pathway activation. The association of ANXA2 to distinct CMSs suggests the possible use of ANXA2 as a prognostic marker or directed target therapy.
Assuntos
Anexina A2/metabolismo , Neoplasias Colorretais/patologia , Transição Epitelial-Mesenquimal , Invasividade Neoplásica , Fator de Transcrição STAT3/metabolismo , Quinases da Família src/metabolismo , Colo/patologia , Humanos , Estadiamento de Neoplasias , Fator de Crescimento Transformador beta/metabolismoRESUMO
OBJECTIVES: To analyse the antineoplastic activity of fractions derived from the hydroalcoholic extract of Euterpe oleracea Mart. seed in the MCF-7 cell line and to identify the compounds responsible for the antineoplastic action. METHODS: Cells were treated with 10, 20, 40 and 60 µg/ml with the hexane, chloroform and ethyl acetate fraction (EAF) of the hydroalcoholic extract of açaí seed, for 24 and 48 h. After treatment, cell viability was measured using MTT assay and cell death was assessed using the Annexin-Pi assay. The most cytotoxic fraction under study was analysed by mass spectrometry using an electrospray ionization source and a cyclotron analyser coupled to a Fourier transform. Data were analysed statistically by analysis of variance (ANOVA) or by Student's t-test, where appropriate. KEY FINDINGS: All fractions caused significant reduction in the cell viability, but the EAF was the most cytotoxic (P < 0.001). It was observed the absence of significant annexin staining but increase Pi staining (P < 0.001). The EAF is composed of epicatechin, proanthocyanidin A2 and trimeric and tetrameric procyanidins. CONCLUSIONS: In this study, we demonstrated that EAF was the most effective fraction in reducing cell viability and causing necroptosis in the MCF-7 cell.
Assuntos
Euterpe/química , Extratos Vegetais/química , Extratos Vegetais/farmacologia , Antineoplásicos/química , Antineoplásicos/farmacologia , Antioxidantes/química , Antioxidantes/farmacologia , Catequina/química , Catequina/farmacologia , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Humanos , Células MCF-7 , Proantocianidinas/química , Proantocianidinas/farmacologia , Sementes/químicaRESUMO
The metastatic process in breast cancer is related to the expression of the epithelial-to-mesenchymal transition transcription factors (EMT-TFs) SNAIL, SLUG, SIP1 and TWIST1. EMT-TFs and nuclear factor-κB (NF-κB) activation have been associated with aggressiveness and metastatic potential in carcinomas. Here, we sought to examine the role of NF-κB in the aggressive properties and regulation of EMT-TFs in human breast cancer cells. Blocking NF-κB/p65 activity by reducing its transcript and protein levels (through siRNA-strategy and dehydroxymethylepoxyquinomicin [DHMEQ] treatment) in the aggressive MDA-MB-231 and HCC-1954 cell lines resulted in decreased invasiveness and migration, a downregulation of SLUG, SIP1, TWIST1, MMP11 and N-cadherin transcripts and an upregulation of E-cadherin transcripts. No significant changes were observed in the less aggressive cell line MCF-7. Bioinformatics tools identified several NF-κB binding sites along the promoters of SNAIL, SLUG, SIP1 and TWIST1 genes. Through chromatin immunoprecipitation and luciferase reporter assays, the NF-κB/p65 binding on TWIST1, SLUG and SIP1 promoter regions was confirmed. Thus, we suggest that NF-κB directly regulates the transcription of EMT-TF genes in breast cancer. Our findings may contribute to a greater understanding of the metastatic process of this neoplasia and highlight NF-κB as a potential target for breast cancer treatment.
Assuntos
Neoplasias da Mama/genética , Transição Epitelial-Mesenquimal/genética , Regulação Neoplásica da Expressão Gênica , NF-kappa B/metabolismo , Neoplasias da Mama/patologia , Linhagem Celular Tumoral , Imunoprecipitação da Cromatina , Humanos , Regiões Promotoras Genéticas , Fatores de Transcrição/genéticaRESUMO
Lithium is a well-established non-competitive inhibitor of glycogen synthase kinase-3ß (GSK-3ß), a kinase that is involved in several cellular processes related to cancer progression. GSK-3ß is regulated upstream by PI3K/Akt, which is negatively modulated by PTEN. The role that lithium plays in cancer is controversial because lithium can activate or inhibit survival signaling pathways depending on the cell type. In this study, we analyzed the mechanisms by which lithium can modulate events related to colorectal cancer (CRC) progression and evaluated the role that survival signaling pathways such as PI3K/Akt and PTEN play in this context. We show that the administration of lithium decreased the proliferative potential of CRC cells in a GSK-3ß-independent manner but induced the accumulation of cells in G2/M phase. Furthermore, high doses of lithium increased apoptosis, which was accompanied by decreased proteins levels of Akt and PTEN. Then, cells that were induced to overexpress PTEN were treated with lithium; we observed that low doses of lithium strongly increased apoptosis. Additionally, PTEN overexpression reduced proliferation, but this effect was minor compared with that in cells treated with lithium alone. Furthermore, we demonstrated that PTEN overexpression and lithium treatment separately reduced cell migration, colony formation, and invasion, and these effects were enhanced when lithium treatment and PTEN overexpression were combined. In conclusion, our findings indicate that PTEN overexpression and lithium treatment cooperate to reduce the malignancy of CRC cells and highlight lithium and PTEN as potential candidates for studies to identify new therapeutic approaches for CRC treatment.