RESUMO
Human Papilloma Viruses (HPVs) are the causative agents of cervical cancer although other types of cancers are associated with HPV infection. Type I Interferons can interfere with HPV E6- and/or E7-dependent transformation and can affect microRNA (miRNA) expression. Cancer cells show a specific pattern of miRNA expression and HPVs are able to modulate miRNAs expressed in infected cells. Keratinocytes transduced with E6 and E7 from mucosal HPV-16 or cutaneous HPV-38 (K16 and K38) were studied to analyze the involvement of HPV oncoproteins in the anti-proliferative activity of IFN-ß. In view of our previous data showing senescence induction by the cytokine in K38 cells, we observe that IFN-ß treatment leads to p53-indipendent apoptosis in K16 cells whereas induces senescence in K16 cells if E6 is silenced and p53 expression is restored. The levels of selected miRNAs, deregulated in K16 and K38 cells, can be modulated by IFN-ß when E6 and E7 proteins of HPV-16, but not HPV-38, are expressed.
Assuntos
Apoptose/efeitos dos fármacos , Papillomavirus Humano 16/metabolismo , Interferon beta/farmacologia , Queratinócitos/metabolismo , MicroRNAs/metabolismo , Proteínas Oncogênicas Virais/metabolismo , Proteínas E7 de Papillomavirus/metabolismo , Proteínas Repressoras/metabolismo , Apoptose/genética , Linhagem Celular Transformada , Papillomavirus Humano 16/genética , Humanos , Queratinócitos/patologia , Queratinócitos/virologia , MicroRNAs/genética , Proteínas Oncogênicas Virais/genética , Proteínas E7 de Papillomavirus/genética , Proteínas Repressoras/genética , Proteína Supressora de Tumor p53/genética , Proteína Supressora de Tumor p53/metabolismoRESUMO
PURPOSE: Human papillomaviruses (HPVs) are the causative agents of cervical cancer and are also associated with other types of cancers. HPVs can modulate microRNAs (miRNAs) expressed by infected cells. The production of extracellular vesicles is deregulated in cancer, and their cargo delivered to the microenvironment can promote tumorigenesis. The involvement of HPV oncoproteins on miRNA expression in cells and exosomes was analyzed in keratinocytes transduced with E6 and E7 from mucosal HPV-16 or cutaneous HPV-38 (K16 and K38). METHODS: MiRNAs were investigated through the TaqMan Array Human MicroRNA Cards, followed by real-time RT-PCR assay for specific miRNAs. Selected miRNA targets were analyzed by Western blot and correlated to the HPV oncoproteins by specifically silencing E6 and E7 expression. Exosomes, isolated from K16 and K38 supernatants by differential centrifugations, were quantified through the vesicle-associated acetylcholinesterase activity. RESULTS: MiRNAs deregulated in K16 and K38 cells were identified. HPV-16 and/or HPV-38 E6 and E7 single proteins can modify the expression of selected miRNAs involved in the tumorigenesis, in particular miR-18a, -19a, -34a and -590-5p. The analysis of the content of exosomes isolated from HPV-positive cells revealed the presence of E6 and E7 mRNAs and few miRNAs. MiR-222, a key miRNA deregulated in many cancers, was identified in exosomes from K16 cells. CONCLUSIONS: HPV E6 and/or E7 oncoprotein expression can induce the deregulation of some miRNAs. Through the production and function of exosomes, HPV oncogenes as well as HPV-deregulated miRNAs can potentiate the virus oncogenic effects in the tumor cell microenvironment.