ChLpMab-23: Cancer-Specific Human–Mouse Chimeric Anti-Podoplanin Antibody Exhibits Antitumor Activity via Antibody-Dependent Cellular Cytotoxicity

Abstract

Podoplanin is expressed in many cancers, including oral cancers and brain tumors. The interaction between podoplanin and its receptor C-type lectin-like receptor 2 (CLEC-2) has been reported to be involved in cancer metastasis and tumor malignancy. We previously established many monoclonal antibodies (mAbs) against human podoplanin using the cancer-specific mAb (CasMab) technology. LpMab-23 (IgG, kappa), one of the mouse anti-podoplanin mAbs, was shown to be a CasMab. However, we have not shown the usefulness of LpMab-23 for antibody therapy against podoplanin-expressing cancers. In this study, we first determined the minimum epitope of LpMab-23 and revealed that Gly54-Leu64 peptide, especially Gly54, Thr55, Ser56, Glu57, Asp58, Arg59, Tyr60, and Leu64 of podoplanin, is a critical epitope of LpMab-23. We further produced human-mouse chimeric LpMab-23 (chLpMab-23) and investigated whether chLpMab-23 exerts antibody-dependent cellular cytotoxicity (ADCC) and antitumor activity. In flow cytometry, chLpMab-23 showed high sensitivity against a podoplanin-expressing glioblastoma cell line, LN319, and an oral cancer cell line, HSC-2. chLpMab-23 also showed ADCC activity against podoplanin-expressing CHO cells (CHO/podoplanin). In xenograft models with HSC-2 and CHO/podoplanin, chLpMab-23 exerts antitumor activity using human natural killer cells, indicating that chLpMab-23 could be useful for antibody therapy against podoplanin-expressing cancers.

Epitope Mapping of Monoclonal Antibody PMab-48 Against Dog Podoplanin

“…(7) We further showed that Gly54-Leu64 peptide of hPDPN is a critical epitope of LpMab-23. (15) The epitope of PMab-38 for dPDPN is similar to those of LpMab-2 and LpMab-23 for hPDPN. Therefore, this kind of epitope mapping provides important evidence for clinical application of anti-PDPN mAbs.…”

“…(12) In contrast, PMab-38 showed cancer specificity in immunohistochemistry using canine tissues (2) in the same pattern with anti-human PDPN (hPDPN) cancer-specific mAbs, such as LpMab-2 (7,13) and LpMab-23. (6,14,15) We previously showed that Thr55-Leu64 peptide of hPDPN, especially O-glycan attached in Thr55 and Ser56 of hPDPN, is a critical epitope of LpMab-2. (7) We further showed that Gly54-Leu64 peptide of hPDPN is a critical epitope of LpMab-23.…”

Establishment of a monoclonal antibody PMab-225 against alpaca podoplanin for immunohistochemical analyses

“…Those CasMabs against hPDPN can detect only hPDPN-expressing cancer cells, not normal cells, including lymphatic endothelial cells and pulmonary type I alveolar cells. Although LpMab-2 might bind to both a peptide and glycans of hPDPN [ 17 ], LpMab-23 could detect the conformational change of hPDPN peptides, which might be induced by cancer-specific glycans [ 38 ]. Both LpMab-2 and LpMab-23 possess high antitumor activities by those antibody-dependent cellular cytotoxicities (ADCC) [ 38 , 39 ].…”

“…Although LpMab-2 might bind to both a peptide and glycans of hPDPN [ 17 ], LpMab-23 could detect the conformational change of hPDPN peptides, which might be induced by cancer-specific glycans [ 38 ]. Both LpMab-2 and LpMab-23 possess high antitumor activities by those antibody-dependent cellular cytotoxicities (ADCC) [ 38 , 39 ]. Furthermore, LpMab-23-recognizing cancer-type podoplanin could be a novel predictor for a poor prognosis of early stage tongue cancer [ 40 ].…”

Expression and Dynamics of Podoplanin in Cultured Osteoblasts with Mechanostress and Mineralization Stimulus

“…When mineralized nodules contact collagen fibers around mineralized nodules, collagen mineralization is propagated from collagen, fiber to fiber [ 4 , 6 , 12 , 25 , 27 ]. Podoplanin is a sialoprotein containing sialic acid with high binding activity such as for platelet aggregation as described above [ 14 – 16 ]. In this study, the anti-podoplanin inhibited the mRNA and protein production of podoplanin, osteopontin, and osteocalcin in osteoblasts under the condition of mineralization (Figs.…”