Monoclonal Antibodies Directed against Cadherin RGD Exhibit Therapeutic Activity against Melanoma and Colorectal Cancer Metastasis

Abstract

New targets are required for the control of advanced metastatic disease. We investigated the use of cadherin RGD motifs, which activate the α2β1integrin pathway, as targets for the development of therapeutic monoclonal antibodies (mAb). Cadherin 17 (CDH17) fragments and peptides were prepared and used for immunization and antibody development. Antibodies were tested for inhibition of β1 integrin and cell adhesion, proliferation, and invasion assays using cell lines from different cancer types (colorectal, pancreatic, melanoma, and breast cancer). Effects of the mAbs on cell signaling were determined by Western blot analysis. Nude mice were used for survival analysis after treatment with RGD-specific mAbs and metastasis development. Antibodies against full-length CDH17 failed to block the binding to α2β1 integrin. However, CDH17 RGD peptides generated highly selective RGD mAbs that blocked CDH17 and vascular-endothelial (VE)-cadherin-mediated β1 integrin activation in melanoma and breast, pancreatic, and colorectal cancer cells. Antibodies provoked a significant reduction in cell adhesion and proliferation of metastatic cancer cells. Treatment with mAbs impaired the integrin signaling pathway activation of FAK in colorectal cancer, of JNK and ERK kinases in colorectal and pancreatic cancers, and of JNK, ERK, Src, and AKT in melanoma and breast cancer. , RGD-specific mAbs increased mouse survival after inoculation of melanoma and colorectal cancer cell lines to cause lung and liver metastasis, respectively. Blocking the interaction between RGD cadherins and α2β1 integrin with highly selective mAbs constitutes a promising therapy against advanced metastatic disease in colon cancer, melanoma, and, potentially, other cancers. .

RGD cadherins and α2β1 integrin in cancer metastasis: A dangerous liaison

“…integrin activation to different extents in all tested cancer cell lines (colorectal, breast and [99]. The only exception is the CDH16 RGD sequence, which did not induce any integrin activation.…”

“…A simultaneous increased expression of CDH17 and the α2 integrin subunit, but an unchanged level of expression of the β1 integrin subunit, was reported for metastatic colorectal cancer cells, suggesting that these two proteins need to be increased to promote metastasis [44]. Proteomic analysis of the CDH17 interactome showed that α2, β1, α6, β4 and αv were the most abundant integrin subunits in metastatic KM12SM colorectal cancer cells [45], although α1 and α3 were also detected by flow cytometry in KM12SM cells, but not α4 and α5 [99]. No role was observed for the α6β4 integrin or the α1, α3 or αv subunits in the prometastatic properties of CDH17 in colorectal cancer cells.…”

“…Recently, synthetic peptides containing the CDH17 RGD motif and their flanking sequences elicited highly specific and selective monoclonal antibodies that inhibited β1 integrin activation and showed anti-metastatic activity in different cancer cell types expressing CDH17 and VE-cadherin (Figure 3) [92]. In contrast, antibodies against fulllength CDH17 were ineffective [99]. Treatment of colorectal, pancreatic, breast and melanoma cancer cells with RGD-specific monoclonal antibodies inhibits signaling mediated by FAK, JNK, ERK, SRC and/or AKT to different extents depending on the cell line and the cancer type.…”

Using of keratin substrate for enrichment of HT29 colorectal cancer stem‐like cells

“…Particularly, adhesion, proliferation, invasion, and metastasis of colon cancer on collagen type I and IV and cadherin 17 were promoted through FAK‐mediated extracellular signal‐regulated kinase (ERK) activation (see Supporting Information Tables S3 and S4). Thus, same as collagen type I, it seems that induction of HT29 CSLCs on keratin substrate is mediated by FAK–ERK signaling pathway.…”

Cadherin-6 mediates thrombosisin vivo

“…Treatment of colorectal cancer or melanoma cells with an antibody targeting the cadherin-17 RGD motif reduced their metastatic potential in vivo. [23] Inhibiting tumor-platelet crosstalk is a promising strategy to limit tumor progression and metastasis; RGD cadherins may be promising molecular targets.…”