A Cancer-Specific Monoclonal Antibody against Podocalyxin Exerted Antitumor Activities in Pancreatic Cancer Xenografts

Abstract

Podocalyxin (PODXL) overexpression is associated with poor clinical outcomes in various tumors. PODXL is involved in tumor malignant progression through the promotion of invasiveness and metastasis. Therefore, PODXL is considered a promising target of monoclonal antibody (mAb)-based therapy. However, PODXL also plays an essential role in normal cells, such as vascular and lymphatic endothelial cells. Therefore, cancer specificity or selectivity is required to reduce adverse effects on normal cells. Here, we developed an anti-PODXL cancer-specific mAb (CasMab), PcMab-6 (IgG1, kappa), by immunizing mice with a soluble PODXL ectodomain derived from a glioblastoma LN229 cell. PcMab-6 reacted with the PODXL-positive LN229 cells but not with PODXL-knockout LN229 cells in flow cytometry. Importantly, PcMab-6 recognized pancreatic ductal adenocarcinoma (PDAC) cell lines (MIA PaCa-2, Capan-2, and PK-45H) but did not react with normal lymphatic endothelial cells (LECs). In contrast, one of the non-CasMabs, PcMab-47, showed high reactivity to both the PDAC cell lines and LECs. Next, we engineered PcMab-6 into a mouse IgG2a-type (PcMab-6-mG2a) and a humanized IgG1-type (humPcMab-6) mAb and further produced the core fucose-deficient types (PcMab-6-mG2a-f and humPcMab-6-f, respectively) to potentiate the antibody-dependent cellular cytotoxicity (ADCC). Both PcMab-6-mG2a-f and humPcMab-6-f exerted ADCC and complement-dependent cellular cytotoxicity in the presence of effector cells and complements, respectively. In the PDAC xenograft model, both PcMab-6-mG2a-f and humPcMab-6-f exhibited potent antitumor effects. These results indicated that humPcMab-6-f could apply to antibody-based therapy against PODXL-expressing pancreatic cancers.

A Cancer-Specific Monoclonal Antibody against HER2 Exerts Antitumor Activities in Human Breast Cancer Xenograft Models

“…Therefore, tumor-selective or -specific mAbs would minimize the adverse effects. We developed CasMabs against podoplanin (LpMab-2 and LpMab-23 [30]), podocalyxin (PcMab-6 [31]), and HER2 (H2Mab-250 [22]) by evaluating the reactivity against cancer and normal cells in flow The BT-474 tumors from the H 2 Mab-250-hG 1 -and trastuzumab-treated mice weighed significantly less than those from the control human IgG-treated mice (59% and 57% reduction, respectively; p < 0.01, Figure 6C,E). The SK-BR-3 tumors from the H 2 Mab-250-hG 1 and trastuzumab-treated mice weighed significantly less than those from the control human IgG-treated mice (48% and 48% reduction, respectively; p < 0.01, Figure 6D,F).…”

“…Therefore, tumor-selective or -specific mAbs would minimize the adverse effects. We developed CasMabs against podoplanin (LpMab-2 and LpMab-23 [30]), podocalyxin (PcMab-6 [31]), and HER2 (H 2 Mab-250 [22]) by evaluating the reactivity against cancer and normal cells in flow cytometry. We also showed the in vivo antitumor effect of the recombinant mAbs (mouse IgG 2a or human IgG 1 types) derived from the abovementioned mAbs [30][31][32].…”

“…We developed CasMabs against podoplanin (LpMab-2 and LpMab-23 [30]), podocalyxin (PcMab-6 [31]), and HER2 (H 2 Mab-250 [22]) by evaluating the reactivity against cancer and normal cells in flow cytometry. We also showed the in vivo antitumor effect of the recombinant mAbs (mouse IgG 2a or human IgG 1 types) derived from the abovementioned mAbs [30][31][32]. In this study, we evaluated the antitumor effect of H 2 Mab-250-mG 2a and H 2 Mab-250-hG 1 , which exhibited a cancer specificity compared to tras-mG 2a and trastuzumab, respectively (Figure 1).…”

Defucosylated Anti-CD44 Monoclonal Antibodies Exert Antitumor Activities against Esophageal Tumor Xenograft

“…We have developed cancer-specific mAbs (CasMabs) against HER2 (H2Mab-214 [44] and H2Mab-250 [45]), podocalyxin (PcMab-6 [46] and PcMab-60 [47]), and podoplanin (LpMab-2 [48] and LpMab-23 [49]) and evaluated the reactivity to cancer and normal cells in flow cytometry. We also reported the antitumor effect in mouse xenograft models using the defucosylated mouse IgG2a or human IgG1 types recombinant mAbs [44,46,[48][49][50][51][52]. Some anti-CD44 mAbs which exhibit cancer specificity have been reported [53].…”

C₈Mab-21: A Novel Anti-human CCR8 Monoclonal Antibody for Flow Cytometry

“…[45] Furthermore, some of the developed mAbs by the CBIS method exhibited cancer specificity by recognizing unique cancer-specific epitopes. [46][47][48][49][50][51] Therefore, the CBIS method is an efficient and useful tactic for generating diverse antibodies targeting membrane proteins.…”