Cell Specific Matrix Metalloproteinase-1 Regulates Lung Metastasis Synergistically with Smoke Exposure

Area of Science:

• Oncology
• Immunology
• Biochemistry

Background:

• Matrix metalloproteinase-1 (MMP1) degrades extracellular matrix during cancer progression.
• The role of MMP1 from host cells, particularly macrophages and lung cells, in tumorigenesis and metastasis is not fully understood.

Purpose of the Study:

• To investigate the function of MMP1 expressed by tumor-associated macrophages (TAMs) and lung cells in primary tumor development and lung metastasis.
• To determine the impact of cigarette smoke exposure on MMP1 expression and its role in metastasis.

Main Methods:

• Co-culture of macrophages with tumor cells in vitro.
• Exposure to cigarette smoke in vitro and in vivo.
• Generation of transgenic mice expressing human MMP1 specifically in macrophages (Mac-MMP1) or lung cells (Lung-MMP1).

Main Results:

• Macrophage MMP1 expression is enhanced by co-culture with tumor cells and cigarette smoke.
• Macrophage-specific MMP1 (Mac-MMP1) drives primary tumor development and lung metastasis, exacerbated by smoke.
• Lung cell-specific MMP1 (Lung-MMP1) reduced lung colonization, despite decreased collagen deposition in tumors.

Conclusions:

• The cellular origin of MMP1 significantly influences the tumor microenvironment and metastatic potential.
• Macrophage-derived MMP1 plays a critical role in promoting lung metastasis.
• Targeting macrophage MMP1 secretion may represent a therapeutic strategy to reduce lung metastasis.