Vascular-Associated Mononuclear Phagocytes: First-Line Soldiers Ambushing Metastasis

Area of Science:

• Immunology
• Cell Biology
• Oncology

Background:

• Mononuclear phagocytes (MPs) maintain tissue homeostasis by eliminating abnormal cells.
• Vascular-associated mononuclear phagocytes (VaMPs) are crucial sentinels against disseminated tumor cells.
• VaMPs exhibit diverse lifespans and phenotypes influenced by their microenvironment.

Purpose of the Study:

• To review the roles of patrolling monocytes, Kupffer cells, and perivascular macrophages in immunosurveillance during incipient metastasis.
• To explore the molecular mechanisms, including transcription factors and cell surface receptors, underlying VaMP anti-tumor activity.
• To summarize strategies for targeting VaMPs in overt metastasis.

Main Methods:

• Literature review of existing research on mononuclear phagocytes and metastasis.
• Analysis of molecular and cellular mechanisms driving VaMP phenotypic plasticity.
• Synthesis of current knowledge on VaMP roles in immunosurveillance.

Main Results:

• Identified three key VaMP types: patrolling monocytes, Kupffer cells, and perivascular macrophages.
• Highlighted the importance of lineage-determining transcription factors and cell surface receptors in VaMP anti-tumor functions.
• Discussed the phenotypic plasticity of VaMPs in response to the microenvironment.

Conclusions:

• VaMPs play a critical role in immunosurveillance against early-stage cancer metastasis.
• Targeting VaMPs presents a promising therapeutic strategy for managing overt metastasis.
• Further research into VaMP plasticity can optimize anti-cancer treatments.