Anaplastic Thyroid Cancer Cell-Secreted TGF-b1 Induces M2-like Macrophage Polarization of Human Monocytes

GEYSELS ROMINA; BRAICA, MARIA VICTORIA; BRUGO, MARIA BELEN; PELLIZAS, CLAUDIA GABRIELA; NICOLA, JUAN PABLO; CHENG SHEUE-YANN; FOZZATTI, LAURA

Curitiba

Congreso; XIX Latin American Thyroid Congress; 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 (human monocytes). However, it remains to be identified which ATC cell-derived soluble factors drive macrophage activation.Aim: To investigate the effect of ATC cell-derived transforming growth factor β1 (TGF-1) on macrophage phenotype.Methods: THP-1 cells (human monocytes) were treated with human ATC cell lines 8505C or C643-derived conditioned media (ATC-CM) or recombinant human TGF-β1 protein. THP-1 cell proliferation and polarization were assessed by flow cytometry, RT-qPCR and Western blot analysis. TGF-β1 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, TGF-β1 treatment significantly influenced the phenotype of THP-1 cells. The changes involved increased expression of CD163 and CLEC7A, which are classic M2 phenotype markers of TAMs. In contrast, the levels of CCL13, another M2 marker, were decreased. TGF-β1 treatment decreased the proliferation of THP-1 cells and increased the mRNA expression of the pro-inflammatory cytokine IL-6. Moreover, we showed that TGF-β1 induced mRNA and protein levels of the transcription factors SNAIL and SLUG. Accordingly, TGF-β1 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). We validated the clinical significance of the expression of TGF-β ligands and its receptors in human ATC by analyzing public microarray datasets, and found that the expression of TGF-β ligands 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 TGF-1 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.