A novel bispecific antibody targeting CD3 and prolactin receptor (PRLR) against PRLR-expression breast cancer

Abstract

Background: Prolactin receptor (PRLR) is highly expressed in a subset of human breast cancer and prostate cancer, which makes it a potential target for cancer treatment. In clinical trials, the blockade of PRLR was shown to be safe but with poor efficacy. It is therefore urgent to develop new therapies against PRLR target. Bispecific antibodies (BsAbs) could guide immune cells toward tumor cells, and produced remarkable effects in some cancers. Methods: In this study, a bispecific antibody targeting both tumor antigen PRLR and T cell surface CD3 antigen (PRLR-DbsAb) was constructed by split intein mediated protein transsplicing (BAPTS) system for the first time. Its binding activity was determined by Biacore and Flow cytometry, and target-dependent T cell mediated cytotoxicity was detected using LDH release assay. ELISA was utilized to study the secretion of cytokines by immune cells. Subcutaneous tumor mouse models were used to analyze the in vivo anti-tumor effects of PRLR-DbsAb. Results: PRLR-DbsAb in vitro could recruit and activate T cells to promote the release of Th1 cytokines IFN-γ and TNF-α, which could kill PRLR expressed breast cancer cells. In xenograft models with breast cancer cell line T47D, NOD/SCID mice intraperitoneally injected with PRLR-DbsAb exhibited significant inhibition of tumor growth and a longer survival compared to mice treated with PRLR monoclonal antibody (PRLR mAb). Conclusions: Both in vitro and in vivo experiments showed PRLR-DbsAb had a potential therapy of cancer treatment potential therapy for cancer. Immunotherapy may be a promising treatment against the tumor target of PRLR.

Overcoming Challenges for CD3-Bispecific Antibody Therapy in Solid Tumors

“…Furthermore, this table also includes CD3-BsAb formats based on affinity-enhanced TCR-like domains that recognize peptide–human leukocyte antigen (HLA) complexes (immune mobilizing monoclonal T-cell receptors against cancer (ImmTACs)) [ 42 ]. Multiple other TAAs are currently pursued in preclinical studies hoping to make their way to the clinic, including B7-H4, CD133, CD155, claudin 6 (CLDN6), cellular mesenchymal to epithelial transcription factor (C-MET), ephrin receptor A10 (EphA10), folate receptor 1 (FOLR1), HLA-A*24:survivin 2B 80-88 , integrin β4 (ITGB4), P-cadherin, prolactin receptor (PRLR), receptor tyrosine kinase-like orphan receptor 1 (ROR1), TNF-related apoptosis-inducing ligand receptor (TRAIL-R2), transferrin receptor (TfR) and tumor-associated calcium signal transducer 2 (Trop-2) [ 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 , 52 , 53 , 54 , 55 , 56 , 57 , 58 , 59 , 60 , 61 , 62 , 63 , 64 , 65 , 66 , 67 , 68 , 69 ].…”

Emerging Immunotherapies against Novel Molecular Targets in Breast Cancer

“…Prolactin receptor’s ligand, prolactin, is an important hormone generated by the pituitary gland and functions to produce milk and further develop the mammary glands by binding to PRLR within breast tissue [ 69 ]. Prolactin receptor is highly expressed in certain breast cancer subtypes [ 70 ]. In comparison to normal breast epithelium, PRLR is expressed slightly more in the MDA-MB-231 TNBC cell line and is significantly more expressed in SKBR-3 and T47D HER2+ cell lines [ 70 ].…”

“…Prolactin receptor is highly expressed in certain breast cancer subtypes [ 70 ]. In comparison to normal breast epithelium, PRLR is expressed slightly more in the MDA-MB-231 TNBC cell line and is significantly more expressed in SKBR-3 and T47D HER2+ cell lines [ 70 ]. Previous reports utilized a bispecific antibody against HER2 and PRLR to enhance cytotoxicity when combined with HER2 antibody drug conjugate and when the bispecific antibody itself was conjugated to drug [ 71 ].…”

Greatest Hits—Innovative Technologies for High Throughput Identification of Bispecific Antibodies

“…Han et al first described in vitro bioconjugation of a full-length bispecific antibody via intein fusions to precursor antibody fragments within the hinge region and successfully demonstrated in vivo activity of a reconstituted CD3xHer2 T-cell engager mediated by Npu DnaE [28]. A similar approach yielded a CD3xPRLR bispecific antibody for T-cell activation and cytokine release towards PRLR expressing breast cancer cells [104]. In addition to Fc-based bispecifics, also non-Fc, circularly connected VHH fragments (cyclobody) have been developed via SICLOPPS (Split Intein Circular Ligation of Peptides and Proteins) reaction between both C-and N-termini, forming a cyclic conformation after PTS [105].…”