Marotta, Maria (2023) Novel immunogenic therapeutic combinations in anaplastic thyroid carcinoma. [Tesi di dottorato]

	Testo Maria_Marotta_35_COMPLETO.pdf Visibile a [TBR] Amministratori dell'archivio Download (1MB) | Richiedi una copia
Anteprima	Testo Maria_Marotta_35_PARZIALE.pdf Download (751kB) | Anteprima

Abstract

Anaplastic thyroid carcinoma (ATC) is a rare, undifferentiated, aggressive and therapy-resistant tumor of the thyroid follicular epithelium. Conventional chemo/radiotherapy, and targeted therapies directed against components of the Ras/MAPK pathway - a driver oncogenic cascade in thyroid carcinoma (TC) - have been used, but they have shown limited efficacy. Immunogenic cell death (ICD) is a form of apoptosis induced by specific stressors, able to evoke tumor regression through a durable antitumor immune response. Single compounds or combination therapies have been shown to induce ICD in distinct tumor types. Here, we wish to identify novel therapies capable of inducing ICD in ATC. To this aim, we used novel drug combinations against recently identified molecular targets to induce ICD in human ATC. One of the potential targets is represented by the immune checkpoint (IC) Programmed cell death-1 (PD-1). We found that ATC cells express both PD-1 and its ligands, PD-L1/2. The PD-1 intrinsic circuit promoted ATC cell proliferation, migration and tumorigenicity in immunocompromised mice. Accordingly, Nivolumab, a PD-1 neutralizing antibody, blocked these effects. PD-1-mediated activities in ATC cells required the SHP2 tyrosine phosphatase, that, upon membrane recruitment by PD-1, can activate Ras, thus triggering the MAPK pathway. Indeed, SHP099, a SHP2 inhibitor, could block PD-1-mediated mitogenic and migratory activities of ATC cells. Another potential target, previously identified by us in ATC, is represented by interleukin 8 (IL8), an inflammatory chemoattractant cytokine that, by binding its receptors CXCR1/CXCR2, induces proliferation, survival, stemness, motility, tumor formation and immunosuppressive features of ATC cells. The blockade of the IL8 circuits with Reparixin, a non-competitive CXCR1/2 inhibitor, repressed IL8-mediated activities in ATC cells. Furthermore, IL8 potentiated the immunosuppressive properties of TC cells by increasing the expression of IC molecules on their surface. Since PD-1/SHP2 and IL8/CXCR1/2 circuits play a critical role in the maintenance of aggressive ATC features, we tried different combinations of Reparixin, Nivolumab and SHP099, in order to test whether the simultaneous blockade of these circuits could kill murine and human ATC cells in an immunogenic fashion. We found that SHP099, in combination with Nivolumab or with Reparixin, and Nivolumab in combination with Reparixin, exerted cytotoxic/cytostatic effects on both murine and human ATC cell lines. Importantly the formers combinations were more efficient than the latter in inducing ICD hallmarks, including eIF2α phosphorylation, calreticulin (CRT) exposure on cell surface, ANXA1, ATP and HMGB-1 increase. Thus, SHP099, in combination with Nivolumab or Reparixin, will be tested in vivo in syngeneic mice models in order to assess their ability to induce tumor regression and to elicit durable immunity against ATC.

Downloads

Actions (login required)

Modifica documento