Direct Tumor Killing and Immunotherapy through Anti-SerpinB9 Therapy

Area of Science:

• Oncology
• Immunology
• Molecular Biology

Background:

• Cancer therapies aim to eliminate tumors directly or via immune responses, with combined approaches showing variable success.
• Serine protease inhibitor SerpinB9 (Sb9) plays a role in tumor cell survival and immune modulation within the tumor microenvironment (TME).

Purpose of the Study:

• To investigate the therapeutic potential of genetic ablation of SerpinB9 (Sb9) for controlling cancer growth.
• To explore the combined effects of Sb9 deficiency on direct tumor killing and host anti-tumor immunity.

Main Methods:

• Genetic ablation of SerpinB9 (Sb9) in mouse models of cancer.
• Assessment of tumor cell death, T cell-mediated immunity, and immunosuppressive cell populations within the TME.
• Evaluation of tumor growth, survival rates, and therapeutic efficacy of Sb9 inhibition.

Main Results:

• Sb9 deficiency led to granzyme B (GrB)-dependent tumor cell death.
• Sb9-deficient mice displayed enhanced T cell-based anti-tumor immunity.
• A decline in GrB-expressing immunosuppressive cells was observed in the TME of Sb9-deficient mice.
• Maximal tumor growth control and increased survival were achieved when both tumor and host were Sb9-deficient.

Conclusions:

• Targeting SerpinB9 (Sb9) offers a novel therapeutic strategy for cancer by combining direct tumor killing with the potentiation of anti-tumor immunity.
• Sb9 inhibition represents a promising modality for interfering with the TME and enhancing immunotherapy efficacy.