Poster abstracts

Poster number 40 submitted by Sara Rasouli

A Senescent Whole-Cell Vaccine Derived from Conditionally Reprogrammed (CR), Overcome Resistance in Breast Cancer

Sara Rasouli ( 1.Comprehensive Cancer Center 2.Biomedical Science Graduate Program 3.Department of Pathology, College of Medicine, The Ohio State University, Columbus, OH, USA.), Haichang Li (1.Comprehensive Cancer Center), Bei Liu (1.Comprehensive Cancer Center 3.Department of Pathology, College of Medicine, The Ohio State University, Columbus, OH, USA.), Vincenzo Coppola (1.Comprehensive Cancer Center 3.Department of Pathology, College of Medicine, The Ohio State University, Columbus, OH, USA.), Anna Vilgelm (1.Comprehensive Cancer Center 3.Department of Pathology, College of Medicine, The Ohio State University, Columbus, OH, USA.), Jenny L (1.Comprehensive Cancer Center 3.Department of Pathology, College of Medicine, The Ohio State University, Columbus, OH, USA.)

Abstract:
Aggressive cancers, including breast cancer, face challenges of therapeutic resistance and recurrence. Autologous cancer vaccines are limited by difficulties in obtaining sufficient primary tumor material. Our lab uses the Conditional Reprogramming Cell (CRC) method to enable long-term in vitro expansion of primary tumor cells. We are developing a novel vaccine strategy based on cellular senescence, a highly immunogenic state. We hypothesize that irradiated, senescent whole-tumor cells (SWCs) generated via CRC will function as potent, poly-antigenic vaccines to prime robust anti-tumor T-cell responses, synergize with immune checkpoint inhibitors (ICIs), and establish long-term immune memory.
Senescence was induced in murine breast cancer lines by γ-irradiation or Doxorubicin treatment. Immune priming was assessed by injecting SWCs into naïve syngeneic mice, quantifying systemic T-cell activation (CD4⁺, CD8⁺, CD69⁺, PD-1⁺) in spleens and lymph nodes via flow cytometry. Therapeutic efficacy will be evaluated in orthotopic, tumor-bearing mice treated with SWC vaccine + CpG adjuvant, +/- dual ICI blockade (anti–PD-L1/anti–CTLA-4). Endpoints include tumor regression and survival. Vaccine efficacy will also be tested in prophylactic models.
In vivo immune-priming experiments (four weekly injections) demonstrated that senescent tumor cells elicited a robust, systemic adaptive immune response. Compared to controls, SWC-treated mice showed a marked expansion of both CD8α⁺ and CD4⁺ T-cell populations in spleens and lymph nodes. Flow cytometry revealed an activated effector phenotype with elevated CD69 and cytotoxic markers in CD8⁺ T cells. These findings confirm SWCs are highly immunogenic and induce systemic T-cell activation.
Senescent whole-tumor cells derived via the CRC method are a feasible and potent poly-antigenic vaccine platform. Our preliminary data demonstrate this strategy breaks immune tolerance, inducing robust T-cell activation. This provides a strong rationale for advancing this personalized, autologous vaccine to overcome immune resistance and prevent recurrence in aggressive solid tumors.

References:
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Keywords: Cancer Vaccine, Senescence, Immune Checkpoint Inhibitors