Development of anti-PAX3 immune responses; a target for cancer immunotherapy

Area of Science:

• Oncology
• Immunology
• Molecular Biology

Background:

• PAX3 is overexpressed in various human cancers and absent in normal tissues.
• PAX3 has an oncogenic function, making it a potential target for cancer immunotherapy.

Purpose of the Study:

• To investigate the potential of PAX3 as a target for cancer immunotherapy.
• To develop and evaluate a PAX3-specific T cell-based therapy.

Main Methods:

• Screening of PAX3 amino acid sequences for peptides binding to MHC class I.
• Immunization of mice with PAX3 peptides or DNA vectors to elicit anti-PAX3 immune responses.
• Establishment and characterization of anti-PAX3 T cell lines from mice and human blood donors.
• Evaluation of anti-PAX3 T cell therapy in mouse tumor models and assessment of anti-PAX3 responses in a patient.

Main Results:

• Identified specific murine and human PAX3 peptides (GVFINGRPL and KLTEARVQV).
• PAX3-specific immune responses in mice inhibited tumor growth, with enhanced responses using peptide-pulsed dendritic cells.
• Intravenous administration of anti-PAX3 T cells led to regression of established tumors in mice.
• Human PAX3 peptide stimulated T cell growth from healthy donors, showing cytotoxicity against PAX3+ cancer cells.
• Anti-PAX3 immune response detected in a patient receiving dendritic cell vaccination.

Conclusions:

• PAX3 is a promising target for cancer immunotherapy due to its overexpression in cancer and immunogenicity.
• PAX3-specific T cell therapy demonstrates potential for clinical application in treating various cancers.
• The study highlights the feasibility of generating robust and specific anti-PAX3 immune responses in both mice and humans.