Trabectedin Reduces Skeletal Prostate Cancer Tumor Size in Association with Effects on M2 Macrophages and...

Area of Science:

• Immunology
• Oncology
• Pharmacology

Background:

• Macrophages exhibit dual roles in tumor progression, potentially promoting or inhibiting tumor growth.
• Prostate cancer (PCa) skeletal metastasis is a significant clinical challenge.
• Understanding the specific macrophage populations involved in PCa bone metastasis is crucial for developing targeted therapies.

Purpose of the Study:

• To characterize monocyte/macrophage populations in skeletal tumors.
• To elucidate mechanisms by which macrophages support prostate cancer skeletal metastasis.
• To evaluate trabectedin as a potential therapeutic target for PCa bone metastasis.

Main Methods:

• Analysis of CD68+ cells and M2-like macrophages (F4/80+CD206+) in human PCa samples and mouse models.
• In vitro assessment of M1-like versus M2-like macrophage efferocytosis and their impact on cancer cell proliferation.
• In vivo studies evaluating the effect of trabectedin on M2-like macrophages and skeletal tumor growth following PCa cell inoculation.

Main Results:

• Phagocytic CD68+ cells correlated with Gleason score in human PCa.
• M2-like macrophages were identified in PCa bone tumors and demonstrated enhanced efferocytosis of apoptotic tumor cells.
• Soluble factors from efferocytic macrophages promoted PCa cell proliferation in vitro.
• Trabectedin reduced M2-like macrophages in vivo and significantly inhibited skeletal metastatic tumor growth.
• Preventative trabectedin treatment reduced M2-like macrophages and skeletal tumor burden.

Conclusions:

• M2-like monocytes and macrophages play a key role in promoting prostate cancer skeletal metastasis.
• Trabectedin effectively targets M2-like macrophages, reducing PCa skeletal metastasis.
• Trabectedin is a promising therapeutic candidate for treating or preventing prostate cancer bone metastasis.