Blocking podoplanin suppresses growth and pulmonary metastasis of human malignant melanoma

Abstract

Background Podoplanin (PDPN), a transmembrane O -glycoprotein, is up-regulated in many tumors and is involved in tumor metastasis and malignant progression. In previous studies, we generated a functional blocking monoclonal antibody (mAb, SZ168) against the extracellular domain of human PDPN. This study is aimed to investigate whether blocking PDPN by SZ168 inhibits tumor growth and metastasis. Methods Malignant melanoma xenograft model by inoculating subcutaneously human malignant melanoma cell line C8161 into the back of BALB/c nude mice was used. Endogenous PDPN expression in C8161 cells and nasopharyngeal cancer cell line CNE-2 was detected using western blot and flow cytometry. Results SZ168 significantly inhibited C8161 or CNE-2 cell-induced platelet aggregation in a dose-dependent manner with a maximal inhibition of 73.9 ± 3.0% in C8161 cells or 77.1 ± 2.7% in CNE-2 cells. Moreover, SZ168 inhibited the growth and pulmonary metastasis of C8161cells in vivo. The number of lung metastatic foci in the SZ168-treated group was significantly decreased compared with that in the control mouse IgG group (1.61 ± 0.44 vs.3.83 ± 0.60, P < 0.01). Subcutaneous tumor volume, weight, and incidence were also significantly reduced in the SZ168-treated group compared to the control group ( P < 0.05). Additionally, SZ168 recognized PDPN in immunohistochemical analyses of tumor tissue sections. Conclusions SZ168 blocks growth and pulmonary metastasis of human malignant melanoma by inhibiting the interaction between tumor PDPN and platelet CLEC-2 and therefore is a promising antibody for therapeutic development against malignant melanoma.

Phase I/II Clinical Trial of the Anti-Podoplanin Monoclonal Antibody Therapy in Dogs with Malignant Melanoma

“…Recently, PDPN has attracted attention as a novel target antigen for the development of antibody therapy because PDPN is expressed on various refractory tumors. As a blocking antibody, the anti-PDPN neutralizing antibodies MS-1 and SZ168, which inhibit the binding of PDPN expressed on tumor cells and C-type lectin-like receptor 2 expressed on platelets, decreased tumor growth and metastasis in PDPN-overexpressed Chinese hamster ovary (CHO)-K1 cells and human melanoma cell lines xenografted onto mouse models [ 28 , 29 ]. Furthermore, the anti-human PDPN antibody, NZ-12, showed an obvious anti-tumor effect against human malignant pleural mesothelioma in an orthotopic xenograft model by inducing ADCC activity [ 30 ].…”

The Detection of Plasma Soluble Podoplanin of Patients with Breast Cancer and Its Clinical Signification

“…11,12 To date, many studies have shown that the expression of PDPN is related to the malignancy, invasiveness, and metastasis of tumor. 7,13,14 Recently, we developed two monoclonal antibodies (mAb) against human PDPN, SZ-163, and SZ-168, and established an enzyme-linked immunosorbent assay (ELISA) to quantitate plasma soluble PDPN utilizing these two mAbs. 15 In this study, we examined plasma sPDPN levels in controls (CTL, 100 cases), patients with fibroadenomas of breast (FOB, 50 cases), and breast cancer patients (pathological type: invasive ductal carcinoma, IDC, 159 cases) were measured with the newly established ELISA method to evaluate the correlation between sPDPN and tumor occurrence and metastasis status of breast cancer.…”

“…Podoplanin (PDPN), a mucin-type transmembrane glycoprotein known as the marker of lymphatic endothelial cells, 3 is highly expressed in many types of cancer tissue and cells, 4 such as lung cancer, 5 , 6 malignant melanoma, 7 osteosarcoma 8 and brain gliomas. 9 PDPN is the only known endogenous ligand of the C-type lectin-like receptor 2 (CLEC-2) expressed on platelets.…”

“… 11 , 12 To date, many studies have shown that the expression of PDPN is related to the malignancy, invasiveness, and metastasis of tumor. 7 , 13 , 14 …”

PDPN Is Expressed in Various Types of Canine Tumors and Its Silencing Induces Apoptosis and Cell Cycle Arrest in Canine Malignant Melanoma

“…In human SCC and malignant pleural mesothelioma cell lines, PDPN induces EMT and promotes tumor cell invasion and distant metastasis by binding with platelets [21]. Furthermore, anti-PDPN antibodies, which neutralize PDPN-platelet interaction, suppress the tumor growth and pulmonary metastasis of human melanoma and mesothelioma in a mouse model [22,23]. Therefore, it is considered that PDPN enhances tumor malignancy and thus could be used as a therapeutic target for some types of tumors.…”