Construction and evaluation of a novel humanized HER2-specific chimeric receptor

Abstract

IntroductionThe human epidermal growth factor receptor 2 (HER2) represents one of the most studied tumor-associated antigens (TAAs) for cancer immunotherapy. The monoclonal antibody (mAb) trastuzumab has improved the outcomes of patients with HER2+ breast cancer. However, a large number of HER2+ tumors are not responsive to, or become resistant to, trastuzumab-based therapy, and thus more effective therapies targeting HER2 are needed.MethodsHER2-specific T cells were generated by the transfer of genes that encode chimeric antigen receptor (CAR). Using a multistep overlap extension PCR method, we constructed a novel, humanized HER2 CAR-containing, chA21 single-chain variable fragment (scFv) region of antigen-specific mAb and T-cell intracellular signaling chains made up of CD28 and CD3ζ. An interferon γ and interleukin 2 enzyme-linked immunosorbent assay and a chromium-51 release assay were used to evaluate the antitumor immune response of CAR T cells in coculture with tumor cells. Furthermore, SKBR3 tumor–bearing nonobese diabetic/severe combined immunodeficiency (NOD/SCID) mice were treated with HER2 CAR T cells to evaluate antitumor activity. Human CD3+ T cell accumulation in tumor xenograft was detected by immunohistochemistry.ResultschA21-28z CAR was successfully constructed, and both CD4+ and CD8+ T cells were transduced. The expanded HER2 CAR T cells expressed a central memory phenotype and specifically reacted against HER2+ tumor cell lines. Furthermore, the SKBR3 tumor xenograft model revealed that HER2 CAR T cells significantly inhibited tumor growth in vivo. Immunohistochemical analysis showed robust accumulation of human CD3+ T cells in regressing SKBR3 lesions.ConclusionsThe results of this study show that novel chA21 scFv-based, HER2-specific CAR T cells not only recognized and killed HER2+ breast and ovarian cancer cells ex vivo but also induced regression of experimental breast cancer in vivo. Our data support further exploration of the HER2 CAR T-cell therapy for HER2-expressing cancers.

Regional Delivery of Chimeric Antigen Receptor–Engineered T Cells Effectively Targets HER2+ Breast Cancer Metastasis to the Brain

“…In addition to the regional delivery route, our proposed HER2-CAR T-cell immunotherapy also addresses potential toxicity issues by the choice of intracellular costimulatory signaling domain (8)(9)(10)(25)(26)(27). Our data show significant dampening of cytokine production, along with a tendency to require higher HER2 expression for cytokine production by HER2-BBz compared with HER2-28z CAR T cells.…”

Chimeric antigen receptor T cells: a novel therapy for solid tumors

“…Simultaneously, abundant IFN-γ and IL-2 secretion were also detected. In xenograft model, the HER2-specific CAR-T cells also significantly restricted tumor growth [72]. Another study demonstrated that oligoclonal camelid single-domain antibodies (VHHs) could target a range of different epitopes on HER2 antigen.…”

Biodistribution of Novel 68Ga-Radiolabelled HER2 Aptamers in Mice

“…Although xenografting of SKBR3 cells has been established previously in other mouse models [32][33][34], no tumour growth of the SKRB3 xenografts could be observed in the SCID hairless NOD mice. We noticed faster tumour growth for the SKOV3 xenografts versus the MDA-MB-231 xenografts (data not shown).…”