Investigation of immune response in C57Bl/6 and Balb/c athymic mice in oral carcinoma heterotopic xenograft models: the influence of GALR2 functional inhibition

• Grant number: 22/00890-5
• Support Opportunities: Scholarships in Brazil - Post-Doctorate
• Effective date (Start): March 01, 2022
• Effective date (End): January 31, 2023
• Field of knowledge: Health Sciences - Dentistry
• Principal Investigator: Debora Aparecida Pires de Campos Zuccari
• Grantee: Guilherme Henrique Tamarindo
• Host Institution: Faculdade de Medicina de São José do Rio Preto (FAMERP). Secretaria de Desenvolvimento Econômico (São Paulo - Estado). São José do Rio Preto , SP, Brazil
• Associated research grant: 20/00394-2 - Head and neck squamous cell carcinoma (HNSCC) invasion and distant metastasis: relevance and crosstalk between GALR2 and efferocytosis in the tumor microenvironment and hematogenic dissemination, AP.TEM

Abstract

Galanin, originally assigned as neuropeptide, has been associated in several physiologic and pathologic processes, being its activity regulated by GALR1, GALR2 and GALR3 receptors. Specifically, GALR2 exhibits pro-tumoral property in head and neck squamous cells carcinoma (HNSCC) and is the only one among the others expressed in peripheral mononuclear cells. In rodents, HNSSC cells invasion was induced by GALR2 and subsequent COX-2 transcription which leads to tumoral progression via PGE2. In addition, GALR2 may modulate Rap1/p38/MAPK causing the increase in IL-6 and MMP-9. Macrophages are the primary source of PGE2, IL-6 and MMP-9, both relevant mediators of tumor invasion considering an inflammatory microenvironment. Moreover, evidence of the crosstalk between neoplastic cells and macrophages has been reported, being the increase in IL-10 secretion related with macrophage polarization towards a pro-tumoral phenotype, increase in efferocytosis and immunosuppression, facilitating the immune scape as well as invasion/metastasis. HNSCC is remarkably a immunosuppressive disease and recent studies from our research group indicate the galanin immunomodulatory function. However, the influence of GALR2 in the tumor microenvironment, mainly its role in the immune scape, is no clear yet. Therefore, the aim of this proposal is to evaluate the therapeutic potential of GALR2 inhibition with regard to efferocytosis modulation in HNSSC. The central hypothesis of this proposal is that GALR2 inhibition decreases tumor invasion, metastasis and the invasive potential of circulating tumor cells (CTCs). Considering the HNSSC immunosuppressive nature and that the immune response varies according to the xenograft host, firstly we will test both Balb/c and C57bL/6 mice with T cells deficiency to determine which has the less pro-inflammatory profile after LPS injection (100µg i.p.) and arthritis induction with collagen II injection (200µg, tail). For this purpose, the phenotype will be determined based on the peripheric mononuclear cells (PMCs), macrophages and dendritic cells, either in localized or systemic manner, in addition to cytokines profile at the end of stimuli (24h for LPS; 3 weeks for arthritis). Then, we will test which HNSSC cell line is the most suitable to our goal in a bilateral model based on its growth curve and tumor symmetry. This approach will provide evidence of the baseline (control tumor) and the most appropriate timepoint for experimental intervention. Lastly, we will evaluate the GALR2 inhibition on HNSSC with regard to tumor invasion, metastasis and hematogenic dissemination.