Exposure to tobacco products and the development of lung cancer: effects on macrophage polarization

• Grant number: 24/23612-6
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: April 01, 2025
• End date: March 31, 2026
• Field of knowledge: Health Sciences - Pharmacy - Toxicological Analysis
• Principal Investigator: Sandra Helena Poliselli Farsky
• Grantee: Guilherme Ponciano de Barros
• Host Institution: Faculdade de Ciências Farmacêuticas (FCF). Universidade de São Paulo (USP). São Paulo , SP, Brazil

Abstract

Smoking is a major public health challenge due to the harmful effects of compounds present in cigarette smoke derived from tobacco combustion. In an attempt to reduce cigarette toxicity, devices for exposure to heated nicotine via inhalation are available on the market, although their toxicity has not been properly established. The lungs, as organs directly exposed to inhaled products, are susceptible to the aggressions of smoking, manifested by inflammatory diseases and tumors. It is known that the development of solid tumors is influenced by the immune system surrounding the tumor, and macrophages play a fundamental role in the process. Macrophages are plastic cells that change their phenotype according to the microenvironment. In this sense, macrophages with a pro-inflammatory phenotype (M1) exert antitumor actions, and M2 or tumor-associated macrophages (TAM) are pro-tumor. The objective of this project is to evaluate the impact of exposure to conventional cigarettes (CC), nicotine inhaled by vapor released by electronically heated tobacco products (HTP) on the biology of lung tumor lineages and on macrophage polarization. For this purpose, A549 cells (lung tumor) and THP-1 (monocyte that differentiates into macrophages) will be cultured in supplemented RPMI 1640 medium and will be subjected to exposure to air (control), heated tobacco (HTP) or CC in an exposure chamber. The chamber allows intermittent exposure to air, HTP vapor and CC smoke mixed with the culture medium, mimicking the cell contact obtained in the lung. Cells will be assessed for viability by flow cytometry; A549 cells will be assessed for proliferation by flow cytometry, invasion into matrigel and colony/spheroid formation; macrophages will be analyzed for phenotype markers by flow cytometry. Inflammatory mediators, such as IL-10 and TGF-¿1, will be quantified in the tumor cell supernatant by enzyme-linked immunosorbent assay. Finally, polarization markers (arginase-1, CD163 and CD206) will be analyzed by flow cytometry in macrophages co-cultured with tumor cells previously exposed to air, HTP or CC. Together, the results will contribute to show the effects of exposure to HTP or CC on tumor cells and macrophages on lung cancer evolution.