Involvement of NFkB signaling in CSC accumulation of head and neck carcinoma cell lines resistant to chemotherapy

Author(s)

Letícia Rodrigues de Castro

• Document type: Master's Dissertation
• Press: Ribeirão Preto.
• Institution: Universidade de São Paulo (USP). Faculdade de Odontologia de Ribeirão Preto (PCARP/BC)
• Defense date: 2021-07-22

Examining board members

Luciana Oliveira de Almeida; Manoela Domingues Martins; Ana Carolina Fragoso Motta; Lucas Novaes Teixeira

• Advisor: Luciana Oliveira de Almeida

Abstract

Head and neck squamous cell carcinoma is a high mortality and malignancy disease due to cancer stem cell (CSC) resistance to antineoplastic treatments. NFkB is a transcription factor associated with chemoresistance through activation of importante genes in carcinogenesis. The objective of this study was to evaluate the role of NFkB in the accumulation of CSC in Cisplatin-resistant tongue squamous cell carcinoma cell lines and whether inhibition of the NFkB pathway could reverse the phenomenon of chemoresistance to this drug. In vitro assays were performed with the wild-type CAL-27 and SCC-9 cell lines resistant to Cisplatin (CisR). TNFα was used as an inducer and CBL0137 and Emetine as NFkB inhibitors. An accumulation of NFkB was found in CisR cells and in the CTT + population; further, wild-type cells with TNFα and CisR additionally increased CTT, suggesting involvement of NFkB in accumulating these cells. As IC50 and drug inhibition doses for each strain were established. Administration of CBL0137 decreased NFkB expression in CAL-27 and CXCL8 and TNF in both strains. Emetine reduced NFkB expression in SCC-9. Inhibitors reduced p-NFkB in both cell lines. The inhibitors caused increased gene expression of HDAC1, 2, 9 and SIRT 1 in CAL-27 and of HDAC9 and SIRT1 in SCC9. CBL0137 increased HDAC1 and HDAC11 in SCC9. The treatments reduce the levels of acetylation of histones H3K9, H3K36, H3K79, H4K5 and H4K12 in CAL-27 and of H3K79, H3K79, H4K5 and H4K12 in SCC9; further, CBL0137 reduced H3K36 in SCC9. The combined treatment of Emetine + Cisplatin and CBL0137 + Cisplatin and monotherapy with Emetine reduced the number of CSC in CAL-27, while CBL0137 alone or combined treatment with Cisplatin were more efficient in SCC9. The isolated Emetine treatment was more efficient in reducing CSC in both strains. Both drugs inhibited the colony formation potential and Emetine + Cisplatin and Emetine reduced the number of invasive cells in CAL-27 and SCC-9, respectively. Emetine + Cisplatin was the most efficient treatment in inhibiting the migration potential. With the results obtained, it is suggested that NFkB is related to the accumulation of CSC in CisR cell lines and that its inhibition increases the sensivity to treatment with Cisplatin by reducing the population of CSC and tumor aggressiveness markers. (AU)

• FAPESP's process: 19/05782-3 - Involvement of NFkB signaling in CSC accumulation of head and neck carcinoma cell lines resistant to chemotherapy
• Grantee: Letícia Rodrigues de Castro
• Support Opportunities: Scholarships in Brazil - Master