Avaliação da modulação quimiogenética de neurônios sensoriais nociceptivos NAv 1.8 na disseminação metastática espontânea do carcinoma mamário E0771 para o pulmão

Abstract

Breast cancer is the most common and deadliest neoplasm affecting women worldwide. The majority of cancer-related deaths are attributed to metastatic invasion, making metastasis a key focus of study in recent decades. One of the most frequent metastatic niches for breast cancer is the lung. Although the pulmonary microenvironment has been extensively studied regarding its constitutive circulatory structure, which may be more favorable for the adhesion of neoplastic cells detaching from the primary tumor mass and reaching circulation, resident immunologic cells and other structures within the pulmonary microenvironment have been characterized as potential communication targets between the primary tumor and the lung, even before neoplastic cells settle in this tissue, promoting the so-called pre-metastatic niche. Studies have characterized the presence of neuronal ramifications invading breast tumors; however, understanding the influence of sensory neurons in breast cancer and their role in metastatic dissemination remains incomplete. In this study, transgenic animals with red endogenous fluorescence (TdTomato) and a Designer Receptors Exclusively Activated by a Designer Drug (DREADD) technology were used to perform chemomodulation of Nav 1.8 sensory neurons using N-oxide clozapine (CNO). Animals carrying Nav 1.8 were crossed with DREADD animals harboring the cre recombinase enzyme linked to the G protein Hm3Dq, resulting in Nav 1.8 Cre+/Hm3Dq+ (neuromodulated group, n=7) and Nav 1.8 Cre-/Hm3Dq+ (control group, n=7) offspring. Thus, sensory neuron stimulation could be chemically induced by CNO administration. We characterized the presence of nociceptive terminations Nav1.8 in lung tissue through fluorescence microscopy. Additionally, we observed that chemogenetic modulation of these Nav1.8 neurons plays a crucial role in preserving ventilatory lung function, as evidenced by spirometry. Furthermore, animals with overstimulated sensory innervation (Nav 1.8 Cre+/Hm3Dq+) showed a significant reduction in inflammatory infiltrate foci associated with spontaneous lung metastasis and a decrease in the macrophage population in the pulmonary microenvironment, which is often associated with a worse metastatic prognosis in breast cancer. Moreover, it was characterized that modulation of sensory neurons Nav1.8 promotes a reduction in the population of immunoregulatory profile cells such as ILC3 Reg, Treg + CD4 + cells, and Tc2 + CD8 + cells in the tumor microenvironment, while increasing the population of cytotoxic effector cells with Tc1 + CD8 + profile. Therefore, our findings indicate an immunoprotective effect of sensory innervation, developed by modulation of sensory neurons Nav1.8, hindering tumor progression and pulmonary metastasis.