CN-122011201-A - Bispecific T cell adapter targeting ICAM1 and CD3 and application thereof

Abstract

The invention discloses a dual-specificity T cell adapter targeting ICAM1 and CD3 and application thereof, belonging to the technical field of biological medicine. The dual-specificity T cell adapter HLE-BiIC disclosed by the invention does not depend on antigen presentation of MHC-I molecules, can overcome the problems of 'first signal' deletion and immune escape caused by MHC-I down regulation of undifferentiated thyroid cancer, and can reconstruct high-efficiency anti-tumor immune response in an 'immune pseudo-heat' tumor model. In addition, the anti-tumor activity is obvious in-vitro experiments, particularly in a humanized mouse model, the tumor can be induced to completely regress, and the anti-tumor activity has good biological safety, so that the anti-tumor activity has extremely high clinical transformation value.

Inventors

• GE MINGHUA
• LU BIN
• XU TONG
• HUANG PING

Assignees

• 浙江省人民医院

Dates

Publication Date

20260512

Application Date

20260413

Claims (10)

1. 1. A bispecific T cell engager targeting ICAM1 and CD3 comprising a scaffold comprising an IgG antibody constant region, said scaffold comprising an Fc domain comprising a hinge region, CH2, CH3, characterized in that said bispecific T cell engager is a heterodimer, in particular consisting of a first polypeptide chain and a second polypeptide chain: the first polypeptide chain comprises an ICAM1 specific single-chain variable region, a first flexible connecting peptide, a CD3 specific single-chain variable region, a second flexible connecting peptide and one chain of an Fc domain from the N end to the C end in sequence; the second polypeptide chain comprises, in order from the N-terminus to the C-terminus, the other chain of the Fc domain; The first polypeptide chain and the second polypeptide chain form a stable heterodimer via a Knob-into-Hole structure in the Fc domain; The ICAM 1-specific single-chain variable region in the first polypeptide chain consists of a heavy chain variable region and a light chain variable region derived from an R6.5 clone, and the CD 3-specific single-chain variable region consists of a heavy chain variable region and a light chain variable region derived from an OKT3 clone.
2. 2. The bispecific T cell adapter of claim 1, wherein the IgG antibody scaffold is a human IgG1 antibody scaffold; the CD 3-specific single chain variable region specifically binds to the CD3 epsilon chain; The amino acid sequence of the ICAM1 specific single-chain variable region is shown as SEQ ID NO.7, and the amino acid sequence of the CD3 specific single-chain variable region is shown as SEQ ID NO. 8; The first flexible connecting peptide and the second flexible connecting peptide are of a (Gly 4 Ser) n structure, wherein n is 3 or 4.
3. 3. The dual-specific T cell adaptor of claim 1, wherein the CH3 domains of the first and second polypeptide chains are designed to have a knob structure and a hole structure, respectively, using a knob-into-hole technique; The CH2 domains of the first and second polypeptide chains introduce LALA-PG mutations.
4. 4. A dual specificity T cell adaptor according to any one of claims 1 to 3 wherein the amino acid sequence of the first polypeptide chain is the amino acid sequence at positions 1 to 748 shown in SEQ ID No.4 and the amino acid sequence of the second polypeptide chain is the amino acid sequence at positions 1 to 231 shown in SEQ ID No. 5.
5. 5. An isolated nucleic acid molecule encoding the bispecific T cell adapter of any one of claims 1-3.
6. 6. The nucleic acid molecule of claim 5, wherein the nucleotide sequence encoding said first polypeptide chain is a 1-2244bp sequence as shown in SEQ ID No.1 and the nucleotide sequence encoding said second polypeptide chain is a 1-693bp sequence as shown in SEQ ID No. 2.
7. 7. A recombinant expression vector comprising the nucleic acid molecule of claim 6.
8. 8. A host cell comprising the nucleic acid molecule of claim 6 or transformed with the recombinant expression vector of claim 7.
9. 9. Use of the bispecific T cell adapter of any one of claims 1 to 3 or the nucleic acid molecule of claim 5 or 6 for the preparation of an antitumor drug.
10. 10. An antitumor drug characterized in that the active ingredient is the bispecific T cell adapter of any one of claims 1 to 3 or the nucleic acid molecule of claim 5 or 6, and a pharmaceutically acceptable carrier.

Description

Bispecific T cell adapter targeting ICAM1 and CD3 and application thereof Technical Field The invention belongs to the technical field of biological medicines, and particularly relates to an immunotherapeutic medicine and preparation and application thereof. More particularly, the invention relates to a bispecific antibody (T cell adaptor) which simultaneously targets intercellular adhesion molecule 1 (ICAM 1) and T cell surface antigen CD3, and the application of the antibody in preparing medicaments for treating thyroid cancer, in particular undifferentiated thyroid cancer. Background Undifferentiated thyroid carcinoma (ANAPLASTIC THYROID CANCER, ATC) is a highly malignant solid tumor that originates in the epithelium of thyroid follicles. Although its incidence is only a small percentage of the total incidence of thyroid cancer, it is extremely aggressive and fatal. The current clinical standard treatment regimen mainly includes surgical excision, chemoradiotherapy, and small molecule targeted drugs (e.g., inhibitors against BRAF mutations). However, since ATC progresses very rapidly, most patients lose surgical opportunities when they are diagnosed, and targeted therapy is limited by low frequency of driver mutations and secondary drug resistance which occurs rapidly after therapy, so that clinical benefit groups are very limited, and development of new therapeutic means is needed. In recent years, immunotherapy represented by immune checkpoint inhibitors (ICIs, such as PD-1/PD-L1 antibodies) has changed the treatment modalities of various solid tumors. Pathology studies have shown that ATC tumor tissue is often accompanied by massive infiltration of CD8 + T cells, exhibiting a so-called "immunocaloric tumor" profile. Theoretically, such tumors respond well to ICIs. However, clinical data showed that ATC patients received a lower Objective Remission Rate (ORR) of ICIs treatment and failed to significantly extend overall survival. This "hot and cold" immune Pseudo-heat (Pseudo-hot) phenomenon reveals that ATC has a special immune escape mechanism. Existing studies, including those of the present inventors, indicate that one key mechanism of ATC immune escape is the down-regulation or absence of expression of major histocompatibility complex class I molecules (MHC-I). In classical cellular immune responses, T Cell Receptor (TCR) recognition of tumor antigens must rely on presentation of MHC-I molecules, which are the "first signals" to activate T cells. Down-regulation of MHC-I directly results in structural disruption of the first signal link, such that even if effector T cells successfully infiltrate into the tumor microenvironment, they are in a "functional blindness" state due to the inability to recognize antigens, and the killing procedure cannot be initiated. This mechanism deficiency determines the natural limitations of conventional immunotherapy (e.g., ici, tumor vaccines) relying on endogenous antigen presentation systems in ATC treatment. Therefore, the development of a novel immunotherapeutic strategy which is independent of MHC-I restriction and can directly reconstruct the recognition connection between T cells and tumor cells is a key to breaking through the ATC treatment bottleneck. Intercellular adhesion molecule 1 (ICAM 1/CD 54) is a transmembrane glycoprotein that has been demonstrated to be abnormally high in a variety of malignant tumors. Both applicant's earlier and existing studies indicate that ICAM1 is significantly highly expressed in ATC tissues and that its high expression is positively correlated with poor prognosis, while its expression in normal thyroid and other important organs is relatively low. This differential expression profile makes ICAM1 an ideal therapeutic target. Currently, drugs under investigation for ICAM1 mainly include antibody-coupled drugs (ADCs) and chimeric antigen receptor T cells (CAR-T). However, ADC drugs face systemic toxicity challenges due to endocytic efficiency and toxin shedding, and CAR-T therapy has problems of difficult tissue infiltration, long preparation period, high cost, easy occurrence of T cell exhaustion and the like in solid tumors. T cell adapter (T CELL ENGAGERS, TCES) acts as a bispecific antibody technology, with one end specifically binding to tumor surface antigen and the other end binding to CD3 molecules on the surface of T cells. The biggest advantage of TCE is that its mechanism of action is completely independent of antigen presentation by MHC-I molecules. It can physically pull T cells to tumor cells and directly mimic the first signal to activate T cells, inducing them to release perforin and granzyme to lyse tumor cells. Given the ubiquitous pathological nature of MHC-I down-regulation by ATC, TCE is theoretically one of the best strategies to address ATC immune escape. However, by the present day, no technical solution or application of bispecific antibodies based on ICAM1 and CD3 dual targets in the treatment of und