The thyroid status reprograms T cell lymphoma growth and modulates immune cell frequencies

E VALLI; ADA G. BLIDNER; A J KLECHA; GABRIEL A RABINOVICH; ML BARREIRO ARCOS; SANTIAGO P. MÉNDEZ-HUERGO; MC DIAZ FLAQUE; L COLOMBO; HELENA ANDREA STERLE; MA PAULAZO; F CAYROL; V MEDINA; GA CREMASCHI

JOURNAL OF MOLECULAR MEDICINE (BERLIN, GERMANY)

SPRINGER

Lugar: Berlin; Año: 2016 vol. 94 p. 417 - 429

0946-2716

In spite of considerable evidence on the regulation of immunity by thyroid hormones, the impact of the thyroid status in tumor immunity is poorly understood. Here we evaluated the antitumor immune responses evoked in mice with different thyroid status (euthyroid, hyperthyroid and hypothyroid) that developed solid tumors or metastases after inoculation of syngeneic T lymphoma cells. Hyperthyroid mice showed increased tumor growth along with increased expression of cell cycle regulators compared to hypothyroid and control tumor-bearing mice. However, hypothyroid mice showed a higher frequency of metastases than the other groups. Hyperthyroid mice bearing tumors displayed a lower number of tumor-infiltrating T lymphocytes, lower percentage of functional IFN--producing CD8+ T cells and higher percentage of CD19+ B cells than euthyroid tumor-bearing mice. However, no differences were found in the distribution of lymphocyte subpopulations in tumor-draining lymph nodes (TDLNs) or spleens among different experimental groups. Interestingly, hypothyroid TDLN showed an increased percentage of Treg cells, while hyperthyroid mice displayed increased number and activity of splenic NK cells, which frequency declined in spleens from hypothyroid mice. Moreover, a decreased number of splenic MDSCs was found in tumor-bearing hyperthyroid mice as compared to hypothyroid or euthyroid mice. Moreover, hyperthyroid mice showed increased cytotoxic activity, which declined in hypothyroid mice. Thus, low levels of intratumoral cytotoxic activity would favor tumor local growth in hyperthyroid mice, while regional and systemic antitumor response may contribute to tumor dissemination in hypothyroid animals. Our results highlight the importance of monitoring the thyroid status in patients with T cell lymphomas.