Atrazine promotes breast cancer development by suppressing immune function and upregulating MMP expression

Area of Science:

• Environmental toxicology
• Cancer biology
• Immunology

Background:

• Atrazine is a widely used triazine herbicide found in water sources.
• Previous studies suggest atrazine interferes with immune and endocrine systems and may promote tumors.

Purpose of the Study:

• To investigate the effects of atrazine on 4T1 breast cancer cell development in vitro and in vivo.
• To elucidate the mechanisms by which atrazine influences tumor growth and the immune microenvironment.

Main Methods:

• In vitro and in vivo studies using 4T1 breast cancer cells.
• Assessment of cell proliferation, tumor volume, MMP expression (MMP2, MMP7, MMP9).
• Analysis of immune cell populations (CD4+, CD8+, NK cells, Treg cells) and cytokine levels (IL-4, IFN-γ, TNF-α) in serum and tumor tissues.

Main Results:

• Atrazine exposure increased 4T1 cell proliferation and tumor volume.
• Upregulation of MMP2, MMP7, and MMP9 expression was observed.
• Decreased thymus and spleen indices, reduced CD4+ and CD3+ lymphocyte percentages, and altered CD4+/CD8+ ratios.
• Reduced tumor-infiltrating lymphocytes (CD4+, CD8+, NK cells) and increased Treg cells.
• Increased IL-4 and decreased IFN-γ and TNF-α in serum and tumor microenvironment.

Conclusions:

• Atrazine suppresses systemic and local anti-tumor immune responses.
• Atrazine promotes breast tumor development by upregulating MMPs and altering the immune microenvironment.
• These findings highlight the potential risks of atrazine exposure in the context of breast cancer.