Exploiting the immunogenic potential of standard of care radiation or cisplatin therapy in preclinical models of HPV-associated malignancies

Abstract

BackgroundWhile radiation and chemotherapy are primarily purposed for their cytotoxic effects, a growing body of preclinical and clinical evidence demonstrates an immunogenic potential for these standard therapies. Accordingly, we sought to characterize the immunogenic potential of radiation and cisplatin in human tumor models of HPV-associated malignancies. These studies may inform rational combination immuno-oncology (IO) strategies to be employed in the clinic on the backbone of standard of care, and in so doing exploit the immunogenic potential of standard of care to improve durable responses in HPV-associated malignancies.MethodsRetroviral transduction with HPV16 E7 established a novel HPV-associated sinonasal squamous cell carcinoma (SNSCC) cell line. Three established HPV16-positive cell lines were also studied (cervical carcinoma and head and neck squamous cell carcinoma). Following determination of sensitivities to standard therapies using MTT assays, flow cytometry was used to characterize induction of immunogenic cell stress following sublethal exposure to radiation or cisplatin, and the functional consequence of this induction was determined using impedance-based real time cell analysis cytotoxicity assays employing HPV16 E7-specific cytotoxic lymphocytes (CTLs) with or without N803 (IL-15/IL-15-Rα superagonist) or exogenous death receptor ligands. In vitro observations were translated using an in vivo xenograft NSG mouse model of human cervical carcinoma evaluating cisplatin in combination with CTL adoptive cell transfer.ResultsWe showed that subpopulations surviving clinically relevant doses of radiation or cisplatin therapy were more susceptible to CTL-mediated lysis in four of four tumor models of HPV-associated malignancies, serving as a model for HPV therapeutic vaccine or T-cell receptor adoptive cell transfer. This increased killing was further amplified by IL-15 agonism employing N803. We further characterized that radiation or cisplatin induced immunogenic cell stress in three of three cell lines, and consequently demonstrated that upregulated surface expression of Fas and TRAIL-R2 death receptors at least in part mediated enhanced CTL-mediated lysis. In vivo, cisplatin-induced immunogenic cell stress synergistically potentiated CTL-mediated tumor control in a human model of HPV-associated malignancy.ConclusionStandard of care radiation or cisplatin therapy induced immunogenic cell stress in preclinical models of HPV-associated malignancies, presenting an opportunity poised for exploitation by employing IO strategies in combination with standard of care.

Radiotherapy combined with docetaxel alters the immune phenotype of HNSCC cells and results in increased surface expression of CD137 and release of HMGB1 of specifically HPV-positive tumor cells

“…Kowalczyk et al. found that radiation or CT with cisplatin significantly enhanced CTL-mediated HPV-associated target cell lysis [11] . We revealed that only HPV-positive HNSCC cells release significant more HMGB1 in comparison to HPV-negative ones following RT plus docetaxcel.…”

“…Docetaxel, being a CTA that was proven to enhance overall survival of HNSCC patients in multimodal settings [3] , belongs to the group of taxanes with high immune stimulatory potential [10] . However, it is not known how combination of docetaxel with RT impact on the immune phenotype of HNSCC tumor cells, while the immunogenic potential of RT and cisplatin in human tumor models of HPV-associated malignancies was just recently analyzed [11] .…”

Exploiting an Interleukin-15 Heterodimeric Agonist (N803) for Effective Immunotherapy of Solid Malignancies

“…The proliferative effects of N803 appear more pronounced in NK cell populations and innate memory CD8 + T cells expressing NKG2D [ 39 ]. N803 has been shown to increase the lytic ability of the human herpes virus 16 (HPV16) E7-specific cytotoxic CD8 + T cells in vitro against HPV16 + carcinoma targets, including after target exposure to sublethal radiation [ 44 ].…”