Evaluation of Inflammasome activation in the context of HPV infection and HPV-associated cervical cancer

Author(s)

Fernanda Pereira Fernandes

• Document type: Master's Dissertation
• Press: São Paulo.
• Institution: Universidade de São Paulo (USP). Faculdade de Medicina (FM/SBD)
• Defense date: 2020-12-07

Examining board members

Alessandra Pontillo; Mariane Tami Amano; Maria Notomi Sato; Lara Termini

• Advisor: Alessandra Pontillo

Abstract

Introduction: The contribution of inflammasoma and its cytokines (IL-1beta, IL-18) to Human Papillomavirus (HPV) infection and HPV-associated cervical cancer (CC) (HPV-CC) is not yet fully understood. In vitro HPV infection leads to inhibition of IL-1beta production in primary keratinocytes. On the other hand, studies of genetic association and the production of IL-1beta and / or IL-18 show a positive correlation with the progression of CC. Based on the data obtained in a study of genetic association in a cohort of women with HPV-CC that pointed to IL-1beta as a risk factor for the development of CC, we propose to deepen this finding here. Objective: To investigate the contribution of inflammasome in the tumor microenvironment of HPV-CC. Materials and methods: A genetic association study for inflammasome variants was replicated in a new cohort of 107 women with HPV-CC using allele-specific probes and qPCR. A gene expression analysis was performed using tumor and normal uterine cervix tissue data from public databases (TCGA, GTEX). Cervical tumor cell lines (C33-A, SiHa and HeLa) and monocytes derived from peripheral blood from 39 healthy donors were cultured alone and together (co-culture assay). The activation of the inflammasome was evaluated indirectly through the production of IL-1beta and IL-18 measured in the culture supernatant by ELISA. Specific inflammasome inhibitors have been used in some trials. Results: Genetic analysis demonstrated once again the association between the rs16944 variant (which leads to an increase in IL-1beta) as well as a greater expression of the IL1B gene and a greater risk of developing HPV-CC and a worse prognosis, respectively. The data obtained in the co-culture assays revealed that, only in the spheroid CC cell culture model (not in monolayer), tumor cells do not produce IL-1beta, but induce the activation of the inflammasome and the release of IL -1beta in monocytes. This activation is at least partially dependent on the NLRP3 inflammasome receptor. Conclusion: For the first time, to our knowledge, we demonstrated that the increase in IL-1beta observed in the progression of CC is possibly due to the induction of NLRP3 activation of inflammasome tumor cells in the monocytes of the microenvironment. Therefore, both NLRP3 and IL-1beta can be considered as possible targets for new therapeutic approaches (AU)

• FAPESP's process: 18/04361-1 - Evaluation of the activation of inflammasome in the context of HPV and cervical cancer associated with HPV
• Grantee: Fernanda Pereira Fernandes
• Support Opportunities: Scholarships in Brazil - Master