Redirection of CAR-T Cell Cytotoxicity Using Metabolic Glycan Labeling with Unnatural Sugars.

Area of Science:

• Immunology
• Biochemistry
• Oncology

Background:

• Chimeric antigen receptor (CAR-T) cell therapy shows promise against hematological cancers but faces challenges in solid tumors due to antigen heterogeneity and escape variants.
• Limited efficacy of current CAR-T cell therapies in solid tumors necessitates novel strategies to broaden their applicability.
• Antigen-negative escape variants and high antigen heterogeneity in solid tumors represent significant hurdles for CAR-T cell therapy.

Purpose of the Study:

• To develop a novel cancer immunotherapy strategy by metabolically labeling cancer cell glycans.
• To redirect CAR-T cell cytotoxicity towards cancer cells irrespective of their endogenous antigen expression.
• To overcome challenges of antigen escape and heterogeneity in solid tumors using modified CAR-T cell therapy.

Main Methods:

• Metabolic labeling of cancer cell glycans using unnatural sugars like N-azidoacetylmannosamine.
• Utilizing click chemistry with bicyclo[6.1.0]non-4-yne-fluorescein isothiocyanate to create targetable glycan structures.
• Generating dinitrophenyl-conjugated sialic acid (Sia-DNP) for in situ modification of cancer cell glycans.
• Developing and testing anti-fluorescein isothiocyanate (anti-FITC) and anti-dinitrophenyl (anti-DNP) CAR-T cells for targeted cancer cell killing.
• Evaluating the efficacy of this approach in xenograft models of solid tumors.

Main Results:

• Metabolic glycan modification with N-azidoacetylmannosamine and bicyclo[6.1.0]non-4-yne-fluorescein isothiocyanate induced selective and durable cytotoxicity mediated by anti-FITC CAR-T cells.
• In situ generation of DNP-modified glycans using Sia-DNP enabled effective targeting by anti-DNP CAR-T cells.
• Established solid tumors in xenograft models were eradicated using the Sia-DNP and anti-DNP CAR-T cell strategy.
• Demonstrated proof-of-concept for metabolic glycan labeling as a universal targeting strategy for CAR-T cell therapy.

Conclusions:

• Metabolic glycan labeling with unnatural sugars offers a versatile platform for CAR-T cell therapy.
• This approach overcomes limitations of antigen-specific targeting in solid tumors, including antigen heterogeneity and escape.
• Metabolic glycan labeling combined with CAR-T cell therapy presents a promising new avenue for treating solid tumors lacking viable target antigens.