IGF1R- and ROR1-Specific CAR T Cells as a Potential Therapy for High Risk Sarcomas

Abstract

Patients with metastatic or recurrent and refractory sarcomas have a dismal prognosis. Therefore, new targeted therapies are urgently needed. This study was designed to evaluate chimeric antigen receptor (CAR) T cells targeting the type I insulin-like growth factor receptor (IGF1R) or tyrosine kinase-like orphan receptor 1 (ROR1) molecules for their therapeutic potential against sarcomas. Here, we report that IGF1R (15/15) and ROR1 (11/15) were highly expressed in sarcoma cell lines including Ewing sarcoma, osteosarcoma, alveolar or embryonal rhabdomyosarcoma, and fibrosarcoma. IGF1R and ROR1 CAR T cells derived from eight healthy donors using the Sleeping Beauty (SB) transposon system were cytotoxic against sarcoma cells and produced high levels of IFN-γ, TNF-α and IL-13 in an antigen-specific manner. IGF1R and ROR1 CAR T cells generated from three sarcoma patients released significant amounts of IFN-γ in response to sarcoma stimulation. The adoptive transfer of IGF1R and ROR1 CAR T cells derived from a sarcoma patient significantly reduced tumor growth in pre-established, systemically disseminated and localized osteosarcoma xenograft models in NSG mice. Infusion of IGF1R and ROR1 CAR T cells also prolonged animal survival in a localized sarcoma model using NOD/scid mice. Our data indicate that both IGF1R and ROR1 can be effectively targeted by SB modified CAR T cells and that such CAR T cells may be useful in the treatment of high risk sarcoma patients.

Receptor tyrosine kinase gene expression profiles of Ewing sarcomas reveal ROR1 as a potential therapeutic target in metastatic disease

“…Very recently, a first publication in pediatric sarcomas demonstrated activity of ROR1‐specific CAR T cells (X. Huang et al., 2015). Our data match their FACS‐based ROR1 expression analyses (Figure 5).…”

Engineered T cells: the promise and challenges of cancer immunotherapy

“…ROR1 expression appears to enhance cell survival and prevention of apoptosis, suggesting that tumor downregulation of ROR1 may confer a proliferative disadvantage 44,45 . ROR1-targeted T cells generate cytotoxicity against human ROR1 positive B cell malignancies and sarcoma in preclinical studies 43,46,47 . Importantly, despite low level ROR1 expression in non-tumor tissue, transfer of ROR1-CART cells into nonhuman primates did not cause overt toxicity 48 .…”

CAR T‐cell therapy of solid tumors

“…Examples of novel targets include the type 1 insulin‐like growth factor receptor (IGF1R) and receptor tyrosine kinase‐like orphan receptor 1 (ROR1) for sarcoma 57 as well as the L1‐cell adhesion molecule (L1‐CAM) for ovarian cancer 58 . However, in all cases low‐level expression is still present on non‐malignant tissue, and thus caution must be used before moving these CARs into clinical trials.…”