Purpose: Recombinant nematode anticoagulant protein c2 (rNAPc2) is a specific inhibitor of tissue factor (TF)/factor VIIa complex with novel antithrombotic activity. TF is highly expressed in human colorectal tumors, and levels are positively correlated with disease progression. Experimental Design: To explore the therapeutic potential and mechanism of action of rNAPc2 during tumor growth and metastasis, we tested rNAPc2 in several experimental colorectal cancer models in mice. Results: Administration of rNAPc2 inhibited pulmonary metastasis in mice systemically disseminated with CT26 murine colon carcinoma cells in a dose-dependent fashion. Combining rNAPc2 with the cytotoxic agent 5-fluorouracil or bevacizumab (humanized anti-vascular endothelial growth factor monoclonal antibody) resulted in additive growth inhibition and simultaneous reduction of microvessel density in HCT116 human colorectal tumor xenografts in nude mice. Furthermore, rNAPc2 potentiated CPT-11 in inhibiting hepatic metastasis in nude mice with portal vein injection of HCT116 tumor cells. Long-term administration of rNAPc2 significantly suppressed spontaneous formation of intestinal tumors in Apc Min/+ mice. Using a RNA interference approach, we showed thatTF expression is necessary for rNAPc2-mediated inhibition of HCT116 human colorectal tumor xenograft growth in nude mice, indicating that the antitumor effect of rNAPc2 may be transduced throughTF that is expressed on tumor cells. Conclusions: rNAPc2 is a potent anticancer agent when used in combination with chemotherapy or antiangiogenic therapy in mouse models of colorectal cancer, and TF positivity appears to be required for its activity.

Summary NTB‐A is a CD2‐related cell surface protein expressed primarily on lymphoid cells including B‐lymphocytes from chronic lymphocytic leukaemia (CLL) and lymphoma patients. We have generated a series of monoclonal antibodies (mAbs) against NTB‐A and assessed their therapeutic potential for CLL. Selective mAbs to NTB‐A were further tested in functional complement‐dependent cytotoxicity (CDC) and antibody‐dependent cellular cytotoxicty (ADCC) assays in cell lines and B lymphocytes freshly isolated from CLL patients. While lower levels of NTB‐A were detected in T and natural killer (NK) cells, CDC activity was demonstrated primarily in B cells isolated from CLL patients and B lymphoma cell lines. Knockdown of NTB‐A by small interfering RNA in target cells results in lower cytotoxicity, demonstrating the specificity of the mAbs. Furthermore, anti NTB‐A mAbs demonstrated anti‐tumour activity against CA46 human lymphoma xenografts in nude mice and against systemically disseminated Raji human lymphoma cells in severe combined immunodeficient mice. Taken together, these results demonstrate NTB‐A as a potential new target for immunotherapy of leukaemia and lymphomas.

Supplementary Data from rNAPc2 Inhibits Colorectal Cancer in Mice through Tissue Factor

<div>Abstract<p><b>Purpose:</b> Recombinant nematode anticoagulant protein c2 (rNAPc2) is a specific inhibitor of tissue factor (TF)/factor VIIa complex with novel antithrombotic activity. TF is highly expressed in human colorectal tumors, and levels are positively correlated with disease progression.</p><p><b>Experimental Design:</b> To explore the therapeutic potential and mechanism of action of rNAPc2 during tumor growth and metastasis, we tested rNAPc2 in several experimental colorectal cancer models in mice.</p><p><b>Results:</b> Administration of rNAPc2 inhibited pulmonary metastasis in mice systemically disseminated with CT26 murine colon carcinoma cells in a dose-dependent fashion. Combining rNAPc2 with the cytotoxic agent 5-fluorouracil or bevacizumab (humanized anti-vascular endothelial growth factor monoclonal antibody) resulted in additive growth inhibition and simultaneous reduction of microvessel density in HCT116 human colorectal tumor xenografts in nude mice. Furthermore, rNAPc2 potentiated CPT-11 in inhibiting hepatic metastasis in nude mice with portal vein injection of HCT116 tumor cells. Long-term administration of rNAPc2 significantly suppressed spontaneous formation of intestinal tumors in Apc^Min/+ mice. Using a RNA interference approach, we showed that TF expression is necessary for rNAPc2-mediated inhibition of HCT116 human colorectal tumor xenograft growth in nude mice, indicating that the antitumor effect of rNAPc2 may be transduced through TF that is expressed on tumor cells.</p><p><b>Conclusions:</b> rNAPc2 is a potent anticancer agent when used in combination with chemotherapy or antiangiogenic therapy in mouse models of colorectal cancer, and TF positivity appears to be required for its activity.</p></div>

Supplementary Data from rNAPc2 Inhibits Colorectal Cancer in Mice through Tissue Factor