RESUMEN
BACKGROUND: Oral squamous cell carcinoma has high recurrence and cisplatin resistance. As cancer stem cells, autophagy, and sphingolipids have been appointed as associated with chemotherapy resistance, we tested combined treatments targeting autophagy and/or sphingolipid metabolism with paclitaxel using cisplatin-resistant oral squamous cell carcinoma cells. METHODS: Cisplatin-resistant oral squamous cell carcinoma cells were maintained under exposition to FTY720 and chloroquine combined with paclitaxel and submitted to viability, clonogenicity, and spheres formation assays. The xenograft tumor model using cisplatin-resistant CAL27 cells was adopted to examine the drug combinations' potential antitumoral efficacy. Using an animal model, sphingolipids profiles from plasma and tissue samples were obtained by liquid chromatography coupled to mass spectrometry to identify potential lipids associated with drug response. RESULTS AND DISCUSSION: Our results showed higher autophagic flux in cisplatin-resistant Ooral squamous cell carcinoma (CAL27 and SCC9) cells than in parental cells. The combinations of an autophagy inhibitor (chloroquine) or an autophagy inducer/sphingosine kinase 1 antagonist (FTY720) with paclitaxel (PTX) had a synergistic antitumor effect. Treated CisR cells lost clonogenicity and tumor sphere abilities and reduced proteins associated with proliferation, survival, and cancer stem cells. FTY720 plus PTX had higher antitumor efficacy than PTX against CAL27 CisR xenograft tumor formation. Additionally, increases in glucosylceramide, dehydroglucosylceramide, and sphingomyelin were presented in responsive tumors. CONCLUSION: FTY720 sensitizes cisplatin-resistant oral squamous cell carcinoma cells for paclitaxel.
Asunto(s)
Carcinoma de Células Escamosas , Neoplasias de Cabeza y Cuello , Neoplasias de la Boca , Animales , Humanos , Cisplatino/farmacología , Paclitaxel/farmacología , Clorhidrato de Fingolimod/farmacología , Clorhidrato de Fingolimod/uso terapéutico , Carcinoma de Células Escamosas/tratamiento farmacológico , Carcinoma de Células Escamosas de Cabeza y Cuello , Apoptosis , Neoplasias de la Boca/tratamiento farmacológico , Esfingolípidos/farmacología , Cloroquina/farmacología , Línea Celular Tumoral , Resistencia a AntineoplásicosRESUMEN
Tumor resistance remains an obstacle to successfully treating oral squamous cell carcinoma (OSCC). Cisplatin is widely used as a cytotoxic drug to treat solid tumors, including advanced OSCC, but with low efficacy due to chemoresistance. Therefore, identifying the pathways that contribute to chemoresistance may show new possibilities for improving the treatment. This work explored the role of the tumor necrosis factor-alpha (TNF-alpha)/NFkB signaling in driving the cisplatin resistance of OSCC and its potential as a pharmacological target to overcome chemoresistance. Differential accessibility analysis demonstrated the enrichment of opened chromatin regions in members of the TNF-alpha/NFkB signaling pathway, and RNA-Seq confirmed the upregulation of TNF-alpha/NFkB signaling in cisplatin-resistant cell lines. NFkB was accumulated in cisplatin-resistant cell lines and in cancer stem cells (CSC), and the administration of TNF-alpha increased the CSC, suggesting that TNF-alpha/NFkB signaling is involved in the accumulation of CSC. TNF-alpha stimulation also increased the histone deacetylases HDAC1 and SIRT1. Cisplatin-resistant cell lines were sensitive to the pharmacological inhibition of NFkB, and low doses of the NFkB inhibitors, CBL0137, and emetine, efficiently reduced the CSC and the levels of SIRT1, increasing histone acetylation. The NFkB inhibitors decreased stemness potential, clonogenicity, migration, and invasion of cisplatin-resistant cell lines. The administration of the emetine significantly reduced the tumor growth of cisplatin-resistant xenograft models, decreasing NFkB and SIRT1, increasing histone acetylation, and decreasing CSC. TNF-alpha/NFkB/SIRT1 signaling regulates the epigenetic machinery by modulating histone acetylation, CSC, and aggressiveness of cisplatin-resistant OSCC and the NFkB inhibition is a potential strategy to treat chemoresistant OSCC.
Asunto(s)
Carcinoma de Células Escamosas , Neoplasias de Cabeza y Cuello , Neoplasias de la Boca , Humanos , Carcinoma de Células Escamosas/tratamiento farmacológico , Carcinoma de Células Escamosas/genética , Carcinoma de Células Escamosas/metabolismo , Línea Celular Tumoral , Cisplatino/farmacología , Cisplatino/uso terapéutico , Resistencia a Antineoplásicos , Emetina/metabolismo , Emetina/uso terapéutico , Neoplasias de Cabeza y Cuello/tratamiento farmacológico , Histonas/metabolismo , Neoplasias de la Boca/tratamiento farmacológico , Neoplasias de la Boca/genética , Neoplasias de la Boca/metabolismo , Células Madre Neoplásicas/patología , Sirtuina 1/metabolismo , Carcinoma de Células Escamosas de Cabeza y Cuello/metabolismo , Factor de Necrosis Tumoral alfa/metabolismo , Regulación hacia ArribaRESUMEN
The Wnt/ß-catenin signaling pathway is associated with the regulation of cancer stem cells, and it can be driven by epigenetic modifications. Here, we aim to identify epigenetic modifications involved in the control of the Wnt/ß-catenin signaling and investigate the role of this pathway in the accumulation of cancer stem cells (CSC) and chemoresistance of Head and Neck Squamous Cell Carcinoma (HNSCC). Quantitative-PCR, western blot, shRNA assay, viability assay, flow cytometry assay, spheres formation, xenograft model, and chromatin immunoprecipitation were employed to evaluate the Wnt/ß-catenin pathway and EZH2 in wild-type and chemoresistant oral carcinoma cell lines, and in the populations of CSC and non-stem cells. We demonstrated that ß-catenin and EZH2 were accumulated in cisplatin-resistant and CSC population. The upstream genes of the Wnt/ß-catenin signaling (APC and GSK3ß) were decreased, and the downstream gene MMP7 was increased in the chemoresistant cell lines. The inhibition of ß-catenin and EZH2 combined effectively decreased the CSC population in vitro and reduced the tumor volume and CSC population in vivo. EZH2 inhibition increased APC and GSK3ß, and the Wnt/ß-catenin inhibition reduced MMP7 levels. In contrast, EZH2 overexpression decreased APC and GSK3ß and increased MMP7. EZH2 and ß-catenin inhibitors sensitized chemoresistant cells to cisplatin. EZH2 and H3K27me3 bounded the promoter of APC, leading to its repression. These results suggest that EZH2 regulates ß-catenin by inhibiting the upstream gene APC contributing to the accumulation of cancer stem cells and chemoresistance. Moreover, the pharmacological inhibition of the Wnt/ß-catenin combined with EZH2 can be an effective strategy for treating HNSCC.
Asunto(s)
Cisplatino , Neoplasias de Cabeza y Cuello , Humanos , Carcinoma de Células Escamosas de Cabeza y Cuello/tratamiento farmacológico , Cisplatino/farmacología , Cisplatino/uso terapéutico , beta Catenina/metabolismo , Glucógeno Sintasa Quinasa 3 beta/metabolismo , Metaloproteinasa 7 de la Matriz/genética , Metaloproteinasa 7 de la Matriz/metabolismo , Metaloproteinasa 7 de la Matriz/farmacología , Línea Celular Tumoral , Vía de Señalización Wnt , Neoplasias de Cabeza y Cuello/tratamiento farmacológico , Neoplasias de Cabeza y Cuello/patología , Células Madre Neoplásicas/metabolismo , Regulación Neoplásica de la Expresión Génica , Proteína Potenciadora del Homólogo Zeste 2/metabolismoRESUMEN
BACKGROUND: Chemoresistance is associated with recurrence and metastasis in oral squamous cell carcinoma (OSCC). The cancer stem cell (CSC) subpopulation is highly resistant to therapy, and they are regulated by epigenetic mechanisms. HDACs are histone deacetylase enzymes that epigenetically regulate gene expression. HDAC6 acts on several physiological processes, including oxidative stress, autophagy and DNA damage response, and its accumulation is associated with cancer. Here, we investigate the role of HDAC6 in CSC-mediated chemoresistance in oral carcinoma in addition to its application as a therapeutic target to reverse chemoresistance. METHODS: Wild-type oral carcinoma cell lines (CAL27 WT and SCC9 WT), cisplatin-resistant (CAL27 CisR and SCC9 CisR), and the subpopulations of cancer stem cells (CSC+) and non-stem (CSC-) derived from CisR cells were investigated. HDAC6 accumulation was analyzed by Western blot and immunofluorescence; DNA damage was evaluated by immunofluorescence of phospho-H2A.X; the qPCR for PRDX2, PRDX6, SOD2, and TXN and ROS assay assessed oxidative stress. Apoptosis and CSC accumulation were investigated by flow cytometry. RESULTS: We identified the accumulation of HDAC6 in CisR cell lines and CSC. Cisplatin-resistant cell lines and CSC demonstrated a reduction in DNA damage and ROS and elevated expression of PRDX2. The administration of tubastatin A (a specific HDAC6 inhibitor) increased oxidative stress and DNA damage and decreased PRDX2. Tubastatin A as a monotherapy induced apoptosis in CisR and CSC and reduced the stemness phenotype. CONCLUSION: High levels of HDAC6 sustain CSC subpopulation and chemoresistance in OSCC, suggesting HDAC6 as a pharmacological target to overcome resistance and perhaps prevent recurrence in OSCC.
Asunto(s)
Carcinoma de Células Escamosas , Neoplasias de Cabeza y Cuello , Neoplasias de la Boca , Carcinoma de Células Escamosas de Cabeza y Cuello , Carcinoma de Células Escamosas/tratamiento farmacológico , Carcinoma de Células Escamosas/metabolismo , Línea Celular Tumoral , Cisplatino/farmacología , Cisplatino/uso terapéutico , Resistencia a Antineoplásicos/efectos de los fármacos , Neoplasias de Cabeza y Cuello/patología , Histona Desacetilasa 6/antagonistas & inhibidores , Histona Desacetilasa 6/metabolismo , Histona Desacetilasas/metabolismo , Humanos , Neoplasias de la Boca/patología , Células Madre Neoplásicas/efectos de los fármacos , Células Madre Neoplásicas/metabolismo , Células Madre Neoplásicas/patología , Especies Reactivas de Oxígeno/metabolismo , Carcinoma de Células Escamosas de Cabeza y Cuello/tratamiento farmacológico , Carcinoma de Células Escamosas de Cabeza y Cuello/patologíaRESUMEN
OBJECTIVES: The aims of this study were to investigate the epigenetic mechanisms and biological changes implicated in intrinsic and acquired resistance to cisplatin, a chemotherapy commonly used to treat head and neck squamous cell carcinoma. DESIGN: Intrinsic resistance (IR) was established in CAL-27 and acquired resistance (AR) in SCC-9 cell lines. Changes in the phenotype were evaluated by immunofluorescence, colony assay, invasion and spheres formation. Epigenetic regulation were assessed by quantitative PCR and western blot. RESULTS: Changes DNA damage accumulation, and a decrease of reactive oxygen species in cisplatin-resistant cell lines suggest a protection mechanism against cell death. Increases in aggressiveness, observed by clonogenic and invasive potentials, were more pronounced on the CAL-27 IR cell line. Cancer stem cells (CSC) were increased in cisplatin-resistant cells, and the administration of cisplatin increases CSC accumulation in CAL-27 IR. The loss of adhesion was noticed in CSC from IR cells. The upregulation of the genes HDAC2, HDAC9, SIRT1, KAT2B, KAT6A, KAT6B, and BRD4, the HDAC1 nuclear distribution and the decrease of the acetylated proteins H3K9, H3K36, H3K79, and H4K5 indicate that the IR mobilizes epigenetic modifications in acetylation levels, favoring the aggressiveness phenotype. Therefore, the treatment of CSC derived from CAL-27 IR with the histone deacetylase inhibitor, Vorinostat, partially recovered the CSC adhesion ability by up-regulating the levels of FAK, ß3 integrin, and Vinculin proteins. CONCLUSIONS: Our findings indicate that intrinsic-resistant cells are regulated by epigenetic modifications, which could be a potential target to treat resistant head and neck squamous cell carcinoma.
Asunto(s)
Antineoplásicos , Carcinoma de Células Escamosas , Neoplasias de Cabeza y Cuello , Antineoplásicos/farmacología , Antineoplásicos/uso terapéutico , Carcinoma de Células Escamosas/tratamiento farmacológico , Carcinoma de Células Escamosas/genética , Carcinoma de Células Escamosas/patología , Proteínas de Ciclo Celular/genética , Línea Celular Tumoral , Cisplatino/farmacología , Cisplatino/uso terapéutico , Epigénesis Genética , Neoplasias de Cabeza y Cuello/tratamiento farmacológico , Neoplasias de Cabeza y Cuello/genética , Neoplasias de Cabeza y Cuello/patología , Histona Acetiltransferasas/genética , Histona Acetiltransferasas/metabolismo , Histona Acetiltransferasas/uso terapéutico , Humanos , Células Madre Neoplásicas/metabolismo , Proteínas Nucleares/metabolismo , Carcinoma de Células Escamosas de Cabeza y Cuello/tratamiento farmacológico , Factores de Transcripción/genéticaRESUMEN
Aim: Histone acetylation and methylation control gene expression. We investigated the impact of SET knockdown on histone methylation status and the consequences for the miRNAs levels in oral squamous cell carcinoma (OSCC). Methods: OSCC cells with and without SET knockdown were analyzed by quantitative real-time PCR to determine miRNA levels, and by immunoreactions to histone modifications. Results: The knockdown of SET increased the levels of histone H4K20me2 and miR-137. Still, SET protein binds to the miR-137 promoter region. The transfection of miR-137 mimic reduced the KI67 and Rb proteins and proliferation of OSCC cells. Conclusion: Our results show for the first time a relationship between SET and histone methylation associated with the control of miRNA expression and KI67 and Rb as targets of miR-137 in OSCC.
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Proteínas de Unión al ADN/fisiología , Chaperonas de Histonas/fisiología , Histonas/metabolismo , MicroARNs/genética , Neoplasias de la Boca/genética , Neoplasias de la Boca/metabolismo , Carcinoma de Células Escamosas de Cabeza y Cuello/genética , Carcinoma de Células Escamosas de Cabeza y Cuello/metabolismo , Línea Celular Tumoral , Proliferación Celular , Proteínas de Unión al ADN/metabolismo , Regulación Neoplásica de la Expresión Génica , Chaperonas de Histonas/metabolismo , Humanos , Ácidos Hidroxámicos/farmacología , Antígeno Ki-67/metabolismo , Metilación , MicroARNs/metabolismo , Neoplasias de la Boca/patología , Proteína de Retinoblastoma/metabolismo , Carcinoma de Células Escamosas de Cabeza y Cuello/patologíaRESUMEN
Laser phototherapy (LPT) is widely used in clinical practice to accelerate healing. Although the use of LPT has advantages, the molecular mechanisms involved in the process of accelerated healing and the safety concerns associated with LPT are still poorly understood. We investigated the physiological effects of LPT irradiation on the production and accumulation of reactive oxygen species (ROS), genomic instability, and deoxyribose nucleic acid (DNA) damage in human epithelial cells. In contrast to a high energy density (20 J/cm²), laser administered at a low energy density (4 J/cm²) resulted in the accumulation of ROS. Interestingly, 4 J/cm² of LPT did not induce DNA damage, genomic instability, or nuclear influx of the BRCA1 DNA damage repair protein, a known genome protective molecule that actively participates in DNA repair. Our results suggest that administration of low energy densities of LPT induces the accumulation of safe levels of ROS, which may explain the accelerated healing results observed in patients. These findings indicate that epithelial cells have an endowed molecular circuitry that responds to LPT by physiologically inducing accumulation of ROS, which triggers accelerated healing. Importantly, our results suggest that low energy densities of LPT can serve as a safe therapy to accelerate epithelial healing.
Asunto(s)
Roturas del ADN de Doble Cadena/efectos de la radiación , Células Epiteliales/efectos de la radiación , Terapia por Luz de Baja Intensidad , Especies Reactivas de Oxígeno/metabolismo , Proteína BRCA1/análisis , Proteína BRCA1/metabolismo , Línea Celular , Reparación del ADN , Células Epiteliales/metabolismo , Histonas/análisis , Histonas/metabolismo , Humanos , Especies Reactivas de Oxígeno/análisis , Especies Reactivas de Oxígeno/efectos de la radiaciónRESUMEN
Epidermal growth factor can activate several signaling pathways, leading to proliferation, differentiation, and tumorigenesis of epithelial tissues by binding with its receptor. The EGF protein is involved in nervous system development, and polymorphisms in the EGF gene on chromosome band 4q25 are associated with brain cancers. The purpose of this study was to investigate the association between the single-nucleotide polymorphism of EGF+61G/A and extraaxial brain tumors in a population of the southeast of Brazil. We analyzed the genotype distribution of this polymorphism in 90 patients and 100 healthy subjects, using the polymerase chain reaction-restriction fragment length polymorphism technique. Comparison of genotype distribution revealed a significant difference between patients and control subjects (P < 0.001). The variant genotypes of A/G and G/G were associated with a significant increase of the risk of tumor development, compared with the homozygote A/A (P < 0.0001). When the analyses were stratified, we observed that the genotype G/G was more frequent in female patients (P=0.021). The same genotype was observed more frequently in patients with low-grade tumors (P=0.001). Overall survival rates did not show statistically significant differences. Our data suggest that the EGF A61G polymorphism can be associated with susceptibility to development of these tumors.