c-Met is a chimeric antigen receptor T-cell target for treating recurrent nasopharyngeal carcinoma

Radiation therapy is the standard treatment for patients with nasopharyngeal carcinoma (NPC), but relapse occurs in 10% to 20% of patients. The treatment of recurrent nasopharyngeal carcinoma (rNPC) remains challenging. Chimeric antigen receptors (CAR)-T-cell therapy has achieved good outcomes in the treatment of leukemia and seems to be a promising therapeutic strategy for solid tumors. c-Met has been found to be highly expressed in multiple cancer types, and the activation of c-Met leads to the proliferation and metastasis of cancer cells. However, the expression of c-Met in rNPC tissues and whether it can be used as a target for CAR-T therapy in rNPC remain to be investigated.

We detected the expression of c-Met in 24 primary human rNPC tissues and three NPC cell lines and constructed two different antibody-derived anti-c-Met CARs, namely, Ab928z and Ab1028z. To estimate the function of these two different c-Met-targeted CAR-T cells, CD69 expression, cytotoxicity and cytokine secretion of CAR-T cells were assessed after coculture with target cells. A cell line-derived xenograft mouse model also was used to evaluate these two anti-c-Met CAR-T cells. Furthermore, we determined whether combination with an anti-EGFR antibody could promote the antitumor effect of CAR-T cells in a patient-derived xenograft mouse model.

High c-Met expression was detected in 23 of 24 primary human rNPC tissues by immunohistochemistry staining and in three NPC cell lines by flow cytometry. Ab928z-T cells and Ab1028z-T cells showed significantly upregulated expression of CD69 after coculture with targeted cells. However, Ab1028z-T cells showed superior cytokine secretion and antitumor activity. Furthermore, Ab1028z-T cells effectively suppressed tumor growth compared with control CAR-T cells, and the combination with nimotuzumab further enhanced the tumor-clearing ability of Ab1028z-T cells.

We found that c-Met is highly expressed in rNPC tissues and confirmed its potential as a CAR-T target for rNPC. Our study provides a new idea for the clinical treatment of rNPC.