Myeloid-derived suppressor cells induce multiple myeloma cell survival by activating the AMPK pathway

Area of Science:

• Oncology
• Immunology
• Cell Biology

Background:

• Multiple Myeloma (MM) is an incurable plasma cell malignancy.
• Myeloid-derived suppressor cells (MDSC) are known to promote MM progression via immunosuppression and angiogenesis.
• The direct role of MDSC in MM drug resistance and tumor survival remains unclear.

Purpose of the Study:

• To investigate the direct impact of MDSC on MM cell survival and proliferation.
• To elucidate the molecular mechanisms by which MDSC influence MM cells.
• To evaluate the therapeutic potential of targeting the identified pathways in MM.

Main Methods:

• In vitro co-culture experiments of MM cells with 5TMM-derived MDSC.
• Analysis of AMPK phosphorylation, anti-apoptotic factors (MCL-1, BCL-2), and autophagy markers (LC3II).
• In vivo studies using 5TMM cells in mice and treatment with AMPK inhibitor Compound C.

Main Results:

• Co-culture with MDSC increased MM cell survival and proliferation.
• MDSC induced AMPK phosphorylation in MM cells, correlating with increased MCL-1, BCL-2, and LC3II.
• AMPK activation was partially responsible for the tumor-promoting effect of MDSC.
• Compound C treatment induced apoptosis in various MM cell models.

Conclusions:

• MDSC directly enhance MM cell survival and proliferation.
• AMPK activation is a key mechanism mediating MDSC's pro-survival effect in MM.
• Targeting the AMPK pathway represents a promising therapeutic strategy for MM treatment.