Inhibition of α4β1 Integrin Activity by Small Tellurium Compounds Regulates PD-L1 Expression and Enhances Antitumor...

Area of Science:

• Oncology
• Immunology
• Pharmacology

Background:

• The programmed death-1/programmed death-ligand 1 (PD-1/PD-L1) axis is crucial for tumor immune evasion.
• Targeting the PD-1/PD-L1 axis is a key strategy in cancer immunotherapy.
• Novel approaches are needed to overcome resistance and enhance the efficacy of existing therapies.

Purpose of the Study:

• To investigate the effect of tellurium complexes AS101 and SAS on PD-L1 expression and their potential as cancer therapeutics.
• To elucidate the mechanism by which AS101 and SAS modulate tumor immune evasion.
• To evaluate the combination therapy of AS101 or SAS with αPD-1 antibodies in preclinical cancer models.

Main Methods:

• Assessed PD-L1 expression in human and mouse cancer cells treated with AS101 and SAS.
• Investigated the role of α4β1 very late antigen-4 (VLA-4) integrin activity in mediating the effects of tellurium compounds.
• Analyzed downstream signaling pathways including pAkt and pNFκB.
• Evaluated the impact of SAS on malignant cell death induced by immune cells.
• Assessed the chemosensitivity of cancer cells.
• Conducted in vivo studies using B16/F10 melanoma-bearing mice treated with AS101, SAS, and αPD-1 antibodies.

Main Results:

• AS101 and SAS suppressed PD-L1 expression in various cancer cells by modulating VLA-4 integrin activity.
• These tellurium compounds inhibited pAkt and pNFκB signaling.
• SAS promoted cancer cell death and potentially increased chemosensitivity by inhibiting the VLA-4/IL-10/PD-L1 pathway.
• In vivo, AS101/SAS treatment reduced tumor PD-L1, increased CD8+ T-cell infiltration, and caused tumor shrinkage.
• Combination therapy with αPD-1 antibodies significantly enhanced antitumor efficacy.

Conclusions:

• VLA-4 integrin signaling is critical for tumor immune evasion and represents a viable therapeutic target.
• AS101 and SAS are biologically active tellurium compounds that can enhance the efficacy of αPD-1-based cancer immunotherapy.
• These findings suggest a promising role for tellurium compounds in improving cancer treatment outcomes.