CD70-restricted specific activation of TRAILR1 or TRAILR2 using scFv-targeted TRAIL mutants

J Trebing,D Weisenberger,H Wajant,D Siegmund,V Schäfer,K Silence,M El-Mesery

doi:10.1038/cddis.2013.555

Abstract

To combine the CD27 stimulation inhibitory effect of blocking CD70 antibodies with an antibody-dependent cellular cytotoxicity (ADCC)-independent, cell death-inducing activity for targeting of CD70-expressing tumors, we evaluated here fusion proteins of the apoptosis-inducing TNF family member TRAIL and a single-chain variable fragment (scFv) derived from a high-affinity llama-derived anti-human CD70 antibody (lαhCD70). A fusion protein of scFv:lαhCD70 with TNC-TRAIL, a stabilized form of TRAIL, showed strongly enhanced apoptosis induction upon CD70 binding and furthermore efficiently interfered with CD70-CD27 interaction. Noteworthy, introduction of recently identified mutations that discriminate between TRAILR1 and TRAILR2 binding into the TRAIL part of scFv:lαhCD70-TNC-TRAIL resulted in TRAIL death receptor-specific fusion proteins with CD70-restricted activity.

Highlights

CD70 is strongly expressed with high frequency in a variety of hematologic malignancies and surprisingly often in solid tumors, especially in clear cell renal cell carcinoma and frequently (10–25%) in pancreatic, larynx, ovarian and colon cancer, glioblastoma and melanoma.[11,12,13,14] The reasons and functional relevance of CD70 expression in transformed cells are yet poorly understood and may differ from case to case
With respect to CD70 targeting in cancer, two conceptions are of particular relevance: first, the very well-established idea to exploit CD70 as a tumor marker to direct ADCC-inducing antibodies or antibody–drug conjugates to the malignant cells, which is already in clinical trials, and, second, the relatively new strategy to block the putative immune inhibitory effects of tumor cell-expressed CD70
Most data on CD70 expression are based on immunohistochemistry techniques that do not discriminate between cell surface and intracellularly expressed CD70

Summary

Introduction

CD70 is strongly expressed with high frequency in a variety of hematologic malignancies and surprisingly often in solid tumors, especially in clear cell renal cell carcinoma and frequently (10–25%) in pancreatic, larynx, ovarian and colon cancer, glioblastoma and melanoma.[11,12,13,14] The reasons and functional relevance of CD70 expression in transformed cells are yet poorly understood and may differ from case to case. With respect to CD70 targeting in cancer, two conceptions are of particular relevance: first, the very well-established idea to exploit CD70 as a tumor marker to direct ADCC-inducing antibodies or antibody–drug conjugates to the malignant cells, which is already in clinical trials, and, second, the relatively new strategy to block the putative immune inhibitory effects of tumor cell-expressed CD70. The latter aim could be achieved by ADCC-mediated tumor cell destruction, CD70-blocking antibodies may elicit these effects at lower concentrations insufficient to compensate for the Received 11.7.13; revised 10.12.13; accepted 13.12.13; Edited by M Agostini scFv-targeted receptor-specific TRAIL mutants J Trebing et al inhibitory effect of the endogenously present serum IgG or in the presence of ADCC inhibitory signals/molecules. These bifunctional proteins overcome the poor activity of soluble TRAIL in a CD70-restricted manner and interfere with CD70–CD27 interaction, which in CD70 þ -cancers may have protumoral activities

Methods

Results

Conclusion