ABSTRACT
BACKGROUND High-risk human papillomaviruses (HR-HPVs) are the etiological agents of cervical cancer. Among them, types 16 and 18 are the most prevalent worldwide. The HPV genome encodes three oncoproteins (E5, E6, and E7) that possess a high transformation potential in culture cells when transduced simultaneously. In the present study, we analysed how these oncoproteins cooperate to boost key cancer cell features such as uncontrolled cell proliferation, invasion potential, and cellular redox state imbalance. Oxidative stress is known to contribute to the carcinogenic process, as reactive oxygen species (ROS) constitute a potentially harmful by-product of many cellular reactions, and an efficient clearance mechanism is therefore required. Cells infected with HR-HPVs can adapt to oxidative stress conditions by upregulating the formation of endogenous antioxidants such as catalase, glutathione (GSH), and peroxiredoxin (PRX). OBJECTIVES The primary aim of this work was to study how these oncoproteins cooperate to promote the development of certain cancer cell features such as uncontrolled cell proliferation, invasion potential, and oxidative stress that are known to aid in the carcinogenic process. METHODS To perform this study, we generated three different HaCaT cell lines using retroviral transduction that stably expressed combinations of HPV-18 oncogenes that included HaCaT E5-18, HaCaT E6/E7-18, and HaCaT E5/E6/E7-18. FINDINGS Our results revealed a statistically significant increment in cell viability as measured by MTT assay, cell proliferation, and invasion assays in the cell line containing the three viral oncogenes. Additionally, we observed that cells expressing HPV-18 E5/E6/E7 exhibited a decrease in catalase activity and a significant augmentation of GSH and PRX1 levels relative to those of E5, E6/E7, and HaCaT cells. MAIN CONCLUSIONS This study demonstrates for the first time that HPV-18 E5, E6, and E7 oncoproteins can cooperate to enhance malignant transformation.
Subject(s)
Humans , Cell Transformation, Viral/genetics , Oncogene Proteins, Viral/metabolism , DNA-Binding Proteins/metabolism , Human papillomavirus 18/metabolism , Oxidation-Reduction , Gene Expression Regulation, Neoplastic , Cell Survival , Cell Line, Tumor/virology , Cell ProliferationABSTRACT
ANTECEDENTES: Transformación celular es el mecanismo resultante de la potente acción generada por onco-genes transformantes sobre una célula normal, los cuales con la consiguiente expresión de oncoproteínas determinan drásticos cambios tanto en la morfología como en los volúmenes de los componentes celulares, generando una célula con diferente funcionalidad. OBJETIVO: Precisar las modificaciones que caracterizan al mecanismo transformante en células de epitelio mamario transfectado con el oncogén ras (HC1 Iras) en comparación con su tipo celular normal (HC11GM). MÉTODO: Se estudió con microscopía electrónica de transmisión aplicando técnicas morfométricas a estos tipos celulares con énfasis en los lisosomas, cuantificando variaciones del organelo responsable de la digestión celular. RESULTADOS: Todos los parámetros lisosomales evaluados en el tipo celular transformado presentan diferencias significativas con respecto a la célula normal. CONCLUSIÓN: Las drásticas modificaciones experimentadas por los lisosomas se reflejan en la adquisición de nuevas funcionalidades en la célula transformada.
BACKGROUND: Cellular transformation is the result mechanism of powerful action generated by transforming oncogene over a normal cell, which with the subsequent oncoprotein expression leads to drastic changes in morphology as well as in cell components volumes, generating a cell with a different function. OBJECTIVE: To specify the modifications that characterizes the transforming mechanism in mammary epithelial cells transfected with the ras oncogene comparing them with its normal cell type. METHOD: Transmission electronic microscopy using morphometric techniques was applied to this cell types, emphasizing lysosomes variations, trying to clarify its role in each cell type metabolism. RESULTS: Everyone lysosomal parameters examined in transformed cell type present significant differences regarding to the normal cells. CONCLUSION: The drastic changes in lysosomes reflected in the acquisition of new energy requirements and metabolism in the transformed cell.
Subject(s)
Humans , Female , Breast/cytology , Cell Transformation, Neoplastic , Lysosomes/metabolism , Transfection , Biomarkers , Genes, ras , Mammary Glands, Human/cytology , Microscopy, Electron, Transmission , Cell Proliferation , Epithelial Cells , Lysosomes/ultrastructureABSTRACT
Antecedentes: La adquisición del fenotipo metastático es el resultado de la potente acción generada por oncogenes transformantes sobre una célula normal los cuales con la consiguiente expresión de oncoproteínas determinan drásticos cambios tanto en la morfología como en los volúmenes de los componentes celulares, generando una célula con diferente funcionalidad. Este mecanismo corresponde a la transformación celular. Objetivo: Precisar las modificaciones que caracterizan al mecanismo transformante en células de epitelio mamario transfectado con el oncogén ras (HC11 ras) en comparación con su tipo celular normal (HC11GM). Método: Se estudió con microscopia electrónica de transmisión aplicando técnicas morfométricas a estos tipos celulares con énfasis en las mitocondrias, cuantificando variaciones del organelo generador de energía. Resultados: Todos los parámetros mitocondriales evaluados en el tipo celular transformado presentan diferencias significativas con respecto a la célula normal. Conclusión: Las drásticas modificaciones experimentadas por las mitocondrias se reflejan en la adquisición de nuevos requerimientos energéticos y metabólicos en la célula transformada.
Background: The acquisition of the metastatic phenotype is the result of the transforming oncogene powerful action over a normal cell which with the subsequent oncoprotein expression leads to drastic changes in morphology as well as in cell components volumes, generating a cell with a different function. This mechanism relates to the cell transformation. Objective: To specify the modifications that characterize the transforming mechanism in mammary epithelial cells transfected with the ras oncogene comparing them with its normal cell type. Method: Transmission electronic microscopy using morphometric techniques was applied to this cell types, emphasizing mitochondria variations, trying to clarify its role in each cell type metabolism. Results: Everyone mitochondrial parameters examined in transformed cell type present significant differences regarding to the normal cells. Conclusión: The drastic changes in mitochondria are reflected in the acquisition of new energy requirements and metabolism in the transformed cell.
Subject(s)
Humans , Female , Cell Transformation, Neoplastic , Epithelial Cells/ultrastructure , Genes, ras , Mitochondria , Breast Neoplasms/ultrastructure , Epithelium/ultrastructure , Microscopy, Electron, Transmission , Breast/ultrastructure , TransfectionABSTRACT
Objective:To establish a mouse fibroblastic cell line stably transfected with HMGA1 gene,and to use the cell line to investigate the role of HMGA1 in tumor development and progression.Methods:Eukaryotic expression vector pcDNA3.0-HMGA1 was transfected into NIH3T3 by lipofectamine-mediation.Stable transfectants were selected by G418.The expression of extraneous HMGA1 gene was analyzed by RT-PCR and DNA sequencing.Cell growth was measured through MTT and the cell cycle by FCM.Soft agar colony formation was employed to analyze the ability of anchorage-independent growth.The expression of the immune inhibition factors of VEGF and FasL mRNA was detected by RT-PCR.Results:NIH3T3 cell lines stably expressing HMGA1 gene were successfully established.Comparing with controls,the HMGA1 gene-transfected cells grew faster,acquired the ability of anchorage-independent growth and expressed the immune inhibition factors of VEGF and FasL mRNA.Conclusion:Extraneous expression of HMGA1 gene can induce malignant transformation of NIH3T3 and modulate mRNA expression of immune inhibition factors.HMGA1 gene plays a key role in tumor development,progression and immune escape.