Inhibitory Monoclonal Antibodies and Their Recombinant Derivatives Targeting Surface-Exposed Carbonic Anhydrase XII on Cancer Cells

Dovile Stravinskiene,Lina Baranauskiene,Aurelija Zvirbliene,Aiste Sliziene,Vilma Petrikaite

doi:10.3390/ijms21249411

Abstract

Monoclonal and recombinant antibodies are widely used for the diagnostics and therapy of cancer. They are generated to interact with cell surface proteins which are usually involved in the development and progression of cancer. Carbonic anhydrase XII (CA XII) contributes to the survival of tumors under hypoxic conditions thus is considered a candidate target for antibody-based therapy. In this study, we have generated a novel collection of monoclonal antibodies (MAbs) against the recombinant extracellular domain of CA XII produced in HEK-293 cells. Eighteen out of 24 MAbs were reactive with cellular CA XII on the surface of live kidney and lung cancer cells as determined by flow cytometry. One MAb 14D6 also inhibited the enzymatic activity of recombinant CA XII as measured by the stopped-flow assay. MAb 14D6 showed the migrastatic effect on human lung carcinoma A549 and renal carcinoma A498 cell lines in a ‘wound healing’ assay. It did not reduce the growth of multicellular lung and renal cancer spheroids but reduced the cell viability by the ATP Bioluminescence assay. Epitope mapping revealed the surface-exposed amino acid sequence (35-FGPDGENS-42) close to the catalytic center of CA XII recognized by the MAb 14D6. The variable regions of the heavy and light chains of MAb 14D6 were sequenced and their complementarity-determining regions were defined. The obtained variable sequences were used to generate recombinant antibodies in two formats: single-chain fragment variable (scFv) expressed in E. coli and scFv fused to human IgG1 Fc fragment (scFv-Fc) expressed in Chinese Hamster Ovary (CHO) cells. Both recombinant antibodies maintained the same specificity for CA XII as the parental MAb 14D6. The novel antibodies may represent promising tools for CA XII-related cancer research and immunotherapy.

Highlights

Antibodies, or immunoglobulins (Ig), are components of the humoral adaptive immune response, produced by B lymphocytes [1,2]
To generate monoclonal antibodies (MAbs) against human Carbonic anhydrase XII (CA XII), mice were immunized with the recombinant extracellular domain of human carbonic anhydrase (CA) XII expressed in human cell line HEK-293
The collection of seven high-affinity MAbs against human CA XII was generated using an extracellular catalytic domain of human CA XII expressed in E. coli as an immunogen [49]

Summary

Introduction

Antibodies, or immunoglobulins (Ig), are components of the humoral adaptive immune response, produced by B lymphocytes [1,2]. Recombinant intact immunoglobulin G (IgG) molecules have long half-life; they can accumulate at high concentration in the site of the targeted tumor despite their weak penetration. They can initiate antibody-dependent cellular cytotoxicity (ADCC) providing an additional mechanism for tumor eradication [4,5]. Smaller antibody formats, such as single-chain fragment variable (scFv), may be used for diagnostic and cancer therapy because they maintain the same antigen-binding activities as the intact IgG and have better tumor penetration [3]

Methods

Results

Conclusion