Diverse solid tumors expressing a restricted epitope of L1-CAM can be targeted by chimeric antigen receptor...

Adhesion molecule L1-CAM (CD171) was originally reported to be overexpressed on neuroblastoma and to play an important role during tumor progression. More recently, it has been shown to be overexpressed on many other solid tumors such as melanoma and carcinomas of the cervix, ovary, bladder, and others. Thus, there has been a growing interest in using this cell-surface molecule as a target for both antibody-based and cellular-based therapy-our group has previously examined the clinical utility of chimeric antigen receptor (CAR)-redirected cytolytic T cells that specifically target the CE7 epitope of L1-CAM on neuroblastoma patients. Here, we sought to determine whether this CE7 epitope is present on other recently identified L1-CAM tumors and whether it too can be targeted by CAR T cells. Our studies demonstrate that a diverse array of human tumor cell lines and primary solid tumors (ovarian, lung, and renal carcinoma, glioblastoma and neuroblastoma) do express the CE7 epitope and can efficiently stimulate CE7-specific CAR-redirected (CE7R) T-cell lytic activity and secretion of proinflamatory cytokines. L1-CAM was also detected on a limited number of normal tissues; however, L1-CAM expressed on normal human monocytes was not bound by the CE7 mAb nor was it targeted by CE7R T cells, suggesting that the CE7 epitope is more tumor restricted and not expressed on all L1-CAM tissues. Overall, the CE7 epitope of L1-CAM on a variety of tumors may be amenable to targeting by CE7R T cells, making it a promising target for adoptive immunotherapy.