TARGETED CHEMOTHERAPY STRATEGIES FOR THE ELIMINATION OF TUMOR STEM CELLS IN YOUNG PATIENTS WITH ORAL SQUAMOUS CELL CARCINOMA

• Grant number: 23/13797-6
• Support Opportunities: Scholarships in Brazil - Doctorate
• Start date: January 01, 2025
• End date: February 28, 2027
• Field of knowledge: Health Sciences - Dentistry
• Principal Investigator: Pablo Agustin Vargas
• Grantee: Sebastião Silvério de Sousa Neto
• Host Institution: Faculdade de Odontologia de Piracicaba (FOP). Universidade Estadual de Campinas (UNICAMP). Piracicaba , SP, Brazil
• Associated research grant: 16/05710-4 - Disrupting tumor resistance through therapy targeting depletion of cancer stem cells in head and neck cancer, AP.TEM

Abstract

It is well established in the literature that tumor stem cells (TSCs) play a significant role in the treatment failure of head and neck cancers, as they have shown to be less sensitive to conventional therapies and remain viable afterchemotherapy and radiotherapy, allowing for tumor recurrence and metastasis. Recent findings have demonstrated that the use of Emetine and SAHA(Suberoylanilide hydroxamic acid) reduces the TSC population in mucoepidermoid carcinomas, making the tumor susceptible to cisplatin. However, there are still no studies on the effect of these cli nically approved drugs in squamous cell carcinomas (SCC). Recent evidence has shown that oral tonguecarcinomas (OTC) in young patients have mutations in the reverse transcriptase enzyme of telomerase (hTERT), conferring TSC like characteristics. Thisasso ciation may benefit young patients who exhibit overexpression of hTERT through targeted TSC directed treatment. Objectives: To evaluate in vivo, using animal models, the effect of histonedeacetylase inhibitors (iHDACs) and IkB ± phosphorylation (NF º B super repressor) associated with cisplatin chemotherapy in OTC treatment, characterizing the TSC population and epigenetic modif ications. Methodology: This is an in vivo study using animal models, which will receive patient derived xenografts (PDXs) from young patients (18 40 years old) diagnosed with OTC and treated with surgery at the Head and Neck Service of the Cancer Institut e of the State of São Paulo. All in vivo experiments will be conducted at the Nuclear Medicine Center of the Faculty of Medicine at the University of São Paulo. The PDXs of SCC will be implanted in the dorsal region of NOD/SCID mice, which will be treated with SAHA (iHDAC) and Emetine (iIkB ±), in combination with cisplatin. The clinical response of the tumors will be monitored daily to track changes in tumor volume. After treatment, tumor removal, and euthanasia of the animals, the lesions will be evaluated by flow cytometry(ALDH and CD44) to assess TSC activity. Tumor cells will also be assessed by flow cytometry, by fixation with BrdU combined with propidium iodide total DNA staining, to evaluate the cell cycle phases in the tumor cells present. To assess the maintenance of TSCs through gene expression, histone modification (ac.H3) the maintenance of TSCs through gene expression, histone modification (ac.H3) will be used, with chromatin immunoprecipitation followed by sequencing. These will be used, with chromatin immunoprecipitation followed by sequencing. These tumors will be processed, and the chromatin will be isolated and prepared for tumors will be processed, and the chromatin will be isolated and prepared for ChIP. Previously valChIP. Previously validated ChIP antibodies will be used for chromatin idated ChIP antibodies will be used for chromatin immunoprecipitation. The immunoprecipitated chromatin will be subsequently immunoprecipitation. The immunoprecipitated chromatin will be subsequently sequenced using a statesequenced using a state--ofof--thethe--art sequencer.art sequencer. Expected Results:Expected Results: We hope to demonstrate that the suppression of tumor stem We hope to demonstrate that the suppression of tumor stem cells (Tcells (TSCs) and intervention in IkBSCs) and intervention in IkB± ± phosphorylation, through the prior use of phosphorylation, through the prior use of SAHA and Emetine before the application of the intercalating agent (Cisplatin), SAHA and Emetine before the application of the intercalating agent (Cisplatin), could prevent the development of chemotherapeutic resistance in SCC. By could prevent the development of chemotherapeutic resistance in SCC. By eliminating TSCs and interferingeliminating TSCs and interfering with IkBwith IkB± ± phosphorylation, we believe that the phosphorylation, we believe that the remaining tumor cells will become susceptible to the action of Cisplatin.remaining tumor cells