An Asparagus polysaccharide fraction inhibits MDSCs by inducing apoptosis through toll-like receptor 4

Area of Science:

• Immunology
• Oncology
• Pharmacology

Background:

• Malignant tumors are challenging to treat with conventional methods, necessitating innovative therapeutic strategies.
• Myeloid-derived suppressor cells (MDSCs) are key inhibitors of antitumor immune responses, making them significant targets in cancer therapy.
• Existing cancer treatments often have severe side effects, highlighting the need for safer, more effective approaches.

Purpose of the Study:

• To investigate the anti-MDSC function of Asparagus polysaccharide (AP), a compound derived from the traditional Chinese herb asparagus.
• To evaluate the efficacy of AP in reducing MDSC proliferation and inducing apoptosis in an in vitro colon cancer model.

Main Methods:

• Isolation of MDSCs from the spleens of mice with colon cancer to establish an in vitro model.
• Treatment of isolated MDSCs with AP to assess its effects on cell proliferation and death.
• Analysis of apoptosis pathways, including toll-like receptor 4 (TLR4) dependency and the intrinsic apoptotic pathway (Bax, Caspase-9, Bcl-2 expression).

Main Results:

• AP treatment significantly decreased the proliferation of MDSCs.
• AP induced apoptotic cell death in MDSCs via a TLR4-dependent mechanism.
• AP modulated the expression of key apoptosis-related proteins (Bax, Caspase-9, Bcl-2), indicating activation of the intrinsic apoptotic pathway.

Conclusions:

• Asparagus polysaccharide (AP) demonstrates significant anti-MDSC activity.
• AP attenuates the immunosuppressive function of MDSCs, potentially restoring antitumor immune responses.
• AP shows promise as a novel therapeutic agent for cancer treatment.