Cross-talk between tumors can affect responses to therapy

Area of Science:

• Oncology
• Immunology
• Cancer Microenvironment Research

Background:

• Advanced cancers often present with multiple tumors.
• Tumor microenvironments significantly impact immunotherapy response.
• Interactions between distant tumors and their microenvironments in metastatic settings remain poorly understood.

Purpose of the Study:

• To investigate potential cross-talk between two tumors with distinct microenvironments.
• To determine if this cross-talk affects immunotherapy response in a preclinical model.
• To elucidate the mechanisms underlying distant tumor modulation.

Main Methods:

• Utilized a mouse model with two distinct tumors: visceral and subcutaneous (SC).
• Analyzed SC tumor microenvironment modifications in the presence of visceral tumors.
• Assessed immune cell infiltration (macrophages, T cells, NK cells) and chemokine profiles.
• Evaluated the impact of blocking CCL2 or depleting macrophages on immunotherapy efficacy.

Main Results:

• Immunosuppressive visceral tumors induced resistance to immunotherapy in distant SC tumors.
• SC tumors showed increased M2 macrophage infiltration and reduced effector immune cells (T cells, NK cells) when a kidney tumor was present.
• Blocking CCL2 or depleting macrophages restored SC tumor sensitivity to immunotherapy.

Conclusions:

• A strong immunosuppressive tumor microenvironment can negatively influence distant tumors, rendering them resistant to immunotherapy.
• Targeting M2 macrophages and associated chemokines like CCL2 can overcome this resistance.
• Findings suggest a need to consider inter-tumoral communication in advanced cancer treatment strategies.