Moffitt Cancer Center PS-OP: Predict Radiation-Induced shifts in the Tumor Immune Ecosystem

Predict Radiation-Induced Shifts in Patient-Specific Tumor Immune Ecosystem Composition to Harness Immunological Consequences of Radiotherapy

Tumor-associated antigens, stress proteins, and danger-associated molecular patterns are endogenous immune adjuvants that can both initiate and continually stimulate an immune response against a tumor. In retaliation, tumors can hijack intrinsic immune regulatory programs, thereby facilitating continued growth despite an activated antitumor immune response. Clinically apparent tumors have co-evolved with the patient’s immune system and form a complex Tumor-Immune EcoSystem (TIES).

The success of radiotherapy (RT) may be the result of radiation shifting the relative proportions of tumor and immune cells such that surviving cancer cells are subject to elimination by the immune system. However, current RT fractionation has not specifically focused on enhancing immune responses, nor has immune cell infiltration into the tumor as biomarker been considered to predict treatment response.

We hypothesize that patients with a TIES such that radiation debulks the tumor and induces a robust immune response may be cured. A TIES with weak antitumor-immunity or strong immune suppression may not be sufficiently perturbed by current RT dose fractionation to fully harness radiation-immune synergy and provide tumor control.

The goal of the PS-OP is to combine experimental studies and clinical data to calibrate and rigorously validate the in silico framework that simulates the influence of different TIES compositions on the response to different radiation doses and dose fractionations.

PS-OP investigators are focusing on oropharyngeal cancer, one of the few cancer types increasing in incidence. In vivo tumors with and without tumor specific T cells provide radiation dose and fractionation-dependent changes in immune infiltration to derive in silico model parameters. For clinical analysis, the PS-OP is using a retrospective cohort of 51 oropharyngeal cancer (OPC) tissue samples as training cohort. It is prospectively collecting radiosensitivity and immune infiltration data from 105 OPC patients that undergo radiation therapy with different total doses, dependent on their intrinsic radiosensitivity index (RSI). These data serve as a test cohort to validate model outcome predictions against clinical assessment of complete response at 3 months.

Our overall aims of the PS-OP include:

These aims will motivate profound changes to how we conceive of and clinically prescribe RT. Radiation could be understood as immunotherapy. For patients with unfavorable TIES, RT fractionation protocols should focus on the radical perturbation of the TIES toward immune-modulated tumor control. For favorable TIES, dose could be de-escalated with focus on immune activation.

Integrating our interdisciplinary expertise allows PS-OP researchers to predict RT response and guide decision-making for individual patients, which holds the promise of leading to better outcomes. Successful project completion motivates an in silico model framework-aided clinical trial.

• Determine radiation dose and fractionation that optimize radiation-induced immunity
• Identify how to use RT to shift a patient-specific TIES toward immune-modulated tumor elimination.

These aims will motivate profound changes to how we conceive of and clinically prescribe RT. Radiation could be understood as immunotherapy. For patients with unfavorable TIES, RT fractionation protocols should focus on the radical perturbation of the TIES toward immune-modulated tumor control. For favorable TIES, dose could be de-escalated with focus on immune activation.

Integrating our interdisciplinary expertise allows PS-OP researchers to predict RT response and guide decision-making for individual patients, which holds the promise of leading to better outcomes. Successful project completion motivates an in silico model framework-aided clinical trial.

Investigators

Heiko Enderling, Ph.D.
Moffitt Cancer Center

Dr. Heiko Enderling is an Associate Member of Integrated Mathematical Oncology at Moffitt Cancer Center. He received his Ph.D. in Mathematical Biology from Dundee University, Scotland, in 2006.

Dr. Enderling is interested in quantitative personalized oncology, which is to use mathematical modeling to simulate patient-specific tumor growth dynamics and response to therapy. In particular, he works on radiotherapy modeling and how to personalize and adapt radiotherapy for individual patients based on pre-treatment biology and dynamic responses to intervention. His lab has developed novel dynamic biomarkers to prospectively predict optimal radiation protocols for individual patients.

Shari Pilon-Thomas, Ph.D.
Moffitt Cancer Center

Dr. Shari Pilon-Thomas is an Associate Member of Immunology at Moffitt Cancer Center. Dr. Pilon-Thomas’ primary research focus is on the enhancement of anti-tumor immune responses through the use of vaccines or adoptive cell therapy with tumor infiltrating lymphocytes (TIL) for the treatment of solid tumors.

The goal of the lab is to improve TIL-based therapies and translate findings into TIL-based clinical trials for the treatment of solid tumors, including melanoma, sarcoma, bladder and HPV+ tumors.