ANAPLASTIC THYROID CANCER CELL-SECRETED TGFΒ1 CONTRIBUTES TO THE ACTIVATION OF MACROPHAGES THROUGH MODULATION OF SNAIL AND SLUG EXPRESSION

AGUSTINA JAROSZEWSKI; GEYSELS ROMINA; PELLIZAS, CLAUDIA GABRIELA; MOTRAN, CLAUDIA; STEMPIN, CINTHIA; NICOLA JUAN PABLO; SHEUE-YANN CHENG; FOZZATTI LAURA

San Luis

Congreso; LXXI Reunión Anual de la Sociedad Argentina de Inmunología 2023; 2023

Introduction: Anaplastic thyroid cancer (ATC) is a clinically aggressive form of undifferentiated thyroid cancer with limited treatment options. Tumor-associated macrophages (TAMs) constitute over 50% of ATC-infiltrating cells, and their presence is associated with a poor prognosis. The mechanisms of how TAMs promote ATC progression are not clear. We have previously shown that soluble factors secreted by ATC cells induced pro-tumor M2-like polarization of THP-1 cells. However, it remains to be identified which ATC cell-derived soluble factors drive macrophage activation. It has been previously reported that transforming growth factor β (TGFβ) induces M2-like macrophage phenotype. Therefore, we investigated the involvement of TGFβ1, its main member, on the phenotype of macrophage activation induced by ATC cell-derived conditioned media (CM).Methods: THP-1 cells (human monocytes) were treated with human ATC cell lines 8505C or C643-derived CM (ATC-CM) or recombinant human TGFβ1 protein. THP-1 cells exposed to ATC cell-derived CM, were also treated with a TGFβ receptor inhibitor (SB-431542) 20µM. THP-1 cell proliferation and polarization were assessed by flow cytometry, RT-qPCR and Western blot analysis. TGFβ1 levels in ATC-CM were quantified by ELISA. Gene expression profiles were obtained from the NCBI Gene Expression Omnibus database and analyzed using bioinformatics analysis.Results: Similar to our previous studies using ATC-CM, recombinant human TGFβ1 treatment significantly influenced the phenotype of THP-1 cells. The changes involved increased expression of Dectin1 and CD163, which are classic M2 phenotype markers of TAMs. In contrast, the levels of CCL13, another M2 marker, were decreased. In addition, TGFβ1 treatment decreased the proliferation of THP-1 cells. Moreover, we showed that TGFβ1 induced mRNA and protein levels of the transcription factors SNAIL and SLUG. Accordingly, TGFβ1 was detected in ATC-CM (DMEM, 10.42±5.4pg/mL; 8505C cell-derived CM, 3251±162.5pg/mL; C643 cell-derived CM, 2752±213.1pg/mL). SB-431542 significantly decreased the Dectin1, CD163, SNAIL and SLUG expression promoted by ATC-CM, whereas increased CCL13 expression in THP-1 cells. We validated the clinical significance of the expression of TGFβ ligands, its receptors as well as SNAIL and SLUG in human ATC by analyzing public microarray datasets, and found that the expression of the main TGFβ ligands, TGFβ1, TGFβ2 and TGFβ3, as well as their receptors were significantly higher in human ATC tissue samples than in normal thyroid tissues.Conclusions: Our findings indicate that ATC cell-secreted TGFβ1 may play a key role in M2-like macrophage polarization of human monocytes possible involving the up-regulation of SNAIL and SLUG transcription factors. Thus, ours results uncovered a novel mechanism involved in the activation of TAMs by soluble factors released by ATC cells. Our findings have provided novel rationale basis for the development of original therapies for ATC.