A novel monoclonal antibody SMab-2 recognizes endogenous IDH2-R172S of chondrosarcoma
Xing Liu1, Satoshi Ogasawara2, Mika K Kaneko2
1Department of Regional Innovation, Tohoku University Graduate School of Medicine, 2-1 Seiryo-machi, Aoba-ku, Sendai, Miyagi 980-8575, Japan; Department of Orthopaedic Surgery, Yamagata University Faculty of Medicine, 2-2-2 Iida-nishi, Yamagata 990-9585, Japan.
Abstract:
Isocitrate dehydrogenase 2 (IDH2) mutations have been reported in gliomas, osteosarcomas, cartilaginous tumors, giant cell tumors of bone, and acute myeloid leukemias. Although IDH2 catalyzes the oxidative carboxylation of isocitrate to α-ketoglutarate (α-KG) in mitochondria, mutated IDH2 proteins possess the ability to change α-KG into the oncometabolite R(-)-2-hydroxyglutarate (2-HG). To date, several monoclonal antibodies (mAbs) specific for IDH2 mutations have been established, such as KMab-1 against IDH2-R172K, MMab-1 against IDH2-R172M, and WMab-1 against IDH2-R172W. Although a multi-specific mAb MsMab-1 reacted with IDH2-R172G and IDH2-R172S, a mono-specific mAb against IDH2-R172S has not been established. In this study, we established a novel mAb SMab-2, which recognizes IDH2-R172S but not with wild type IDH2 in ELISA. Although SMab-2 reacted with both IDH1-R132S and IDH2-R172S expressed in Escherichia coli, it reacted with only IDH2-R172S expressed in U-2 OS osteosarcoma cells. Furthermore, SMab-2 recognized endogenous IDH2-R172S protein expressed in SW1353 chondrosarcoma cells in Western blot and immunocytochemical analyses. SMab-2 is expected to be useful for diagnosis of IDH2-R172S-bearing tumors.
Insights
Researchers developed SMab-2, a novel monoclonal antibody targeting the IDH2-R172S mutation. This antibody shows promise for diagnosing tumors, including chondrosarcoma, that harbor this specific isocitrate dehydrogenase 2 mutation.
Area of Science:
- Biochemistry
- Oncology
- Immunology
Background:
- Isocitrate dehydrogenase 2 (IDH2) mutations are implicated in various cancers, including gliomas, osteosarcomas, and acute myeloid leukemias.
- Mutated IDH2 converts α-ketoglutarate (α-KG) to the oncometabolite R(-)-2-hydroxyglutarate (2-HG).
- Existing monoclonal antibodies (mAbs) target specific IDH2 mutations, but a mono-specific mAb for IDH2-R172S was lacking.
Purpose of the Study:
- To establish and characterize a novel monoclonal antibody (mAb) specifically targeting the IDH2-R172S mutation.
- To evaluate the diagnostic potential of the new mAb in various cellular and tissue contexts.
Main Methods:
- Enzyme-linked immunosorbent assay (ELISA) to assess antibody specificity.
- Expression of mutant IDH2 and IDH1 in Escherichia coli and U-2 OS osteosarcoma cells.
- Western blot and immunocytochemical analyses on SW1353 chondrosarcoma cells.
Main Results:
- A novel mAb, SMab-2, was successfully established, demonstrating high specificity for IDH2-R172S.
- SMab-2 recognized IDH2-R172S in both bacterial and cell-based expression systems.
- SMab-2 detected endogenous IDH2-R172S protein in chondrosarcoma cells via Western blot and immunocytochemistry.
Conclusions:
- SMab-2 is a highly specific monoclonal antibody for the IDH2-R172S mutation.
- This novel antibody is a valuable tool for the detection and diagnosis of IDH2-R172S-bearing tumors.
- SMab-2 facilitates the identification of specific IDH2 mutations in cancer diagnostics.
