Activated platelets in the tumor microenvironment for targeting of antibody-drug conjugates to tumors and metastases

May Lin Yap; James D McFadyen; Xiaowei Wang; Melanie Ziegler; Yung-Chih Chen; Abbey Willcox; Cameron J Nowell; Andrew M Scott; Erica K Sloan; P Mark Hogarth; Geoffrey A Pietersz; Karlheinz Peter

doi:10.7150/thno.29146

Activated platelets in the tumor microenvironment for targeting of antibody-drug conjugates to tumors and metastases

Theranostics. 2019 Feb 7;9(4):1154-1169. doi: 10.7150/thno.29146. eCollection 2019.

Authors

May Lin Yap^{1

2}, James D McFadyen^{1

3

4}, Xiaowei Wang^{1

3}, Melanie Ziegler¹, Yung-Chih Chen¹, Abbey Willcox^{1

3

4}, Cameron J Nowell⁵, Andrew M Scott^{6

7}, Erica K Sloan⁵, P Mark Hogarth^{2

8

9}, Geoffrey A Pietersz^{1

2

8

9

10}, Karlheinz Peter^{1

3

9}

Affiliations

¹ Baker Heart and Diabetes Institute, Melbourne, 3004, Australia.
² Department of Clinical Pathology, The University of Melbourne, Melbourne, 3010, Australia.
³ Department of Medicine, Monash University, Melbourne, 3800, Australia.
⁴ Department of Hematology, The Alfred Hospital, Melbourne, 3004, Australia.
⁵ Drug Discovery Biology Theme, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria 3052, Australia.
⁶ Olivia Newton-John Cancer Research Institute, and School of Cancer Medicine, La Trobe University, Melbourne, Victoria, Australia.
⁷ Department of Molecular Imaging and Therapy, Austin Health, and University of Melbourne, Melbourne, Victoria, Australia.
⁸ Burnet Institute, Melbourne, 3004, Australia.
⁹ Department of Immunology, Monash University, Melbourne, 3800, Australia.
¹⁰ College of Health and Biomedicine, Victoria University, Melbourne, 3021, Australia.

Abstract

Rationale: Platelets are increasingly recognized as mediators of tumor growth and metastasis. Hypothesizing that activated platelets in the tumor microenvironment provide a targeting epitope for tumor-directed chemotherapy, we developed an antibody-drug conjugate (ADC), comprised of a single-chain antibody (scFv) against the platelet integrin GPIIb/IIIa (scFv_GPIIb/IIIa) linked to the potent chemotherapeutic microtubule inhibitor, monomethyl auristatin E (MMAE). Methods: We developed an ADC comprised of three components: 1) A scFv which specifically binds to the high affinity, activated integrin GPIIb/IIIa on activated platelets. 2) A highly potent microtubule inhibitor, monomethyl auristatin E. 3) A drug activation/release mechanism using a linker cleavable by cathepsin B, which we demonstrate to be abundant in the tumor microenvironment. The scFv_GPIIb/IIIa-MMAE was first conjugated with Cyanine7 for in vivo imaging. The therapeutic efficacy of the scFv_GPIIb/IIIa-MMAE was then tested in a mouse metastasis model of triple negative breast cancer. Results: In vitro studies confirmed that this ADC specifically binds to activated GPIIb/IIIa, and cathepsin B-mediated drug release/activation resulted in tumor cytotoxicity. In vivo fluorescence imaging demonstrated that the newly generated ADC localized to primary tumors and metastases in a mouse xenograft model of triple negative breast cancer, a difficult to treat tumor for which a selective tumor-targeting therapy remains to be clinically established. Importantly, we demonstrated that the scFv_GPIIb/IIIa-MMAE displays marked efficacy as an anti-cancer agent, reducing tumor growth and preventing metastatic disease, without any discernible toxic effects. Conclusion: Here, we demonstrate the utility of a novel ADC that targets a potent cytotoxic drug to activated platelets and specifically releases the cytotoxic agent within the confines of the tumor. This unique targeting mechanism, specific to the tumor microenvironment, holds promise as a novel therapeutic approach for the treatment of a broad range of primary tumors and metastatic disease, particularly for tumors that lack specific molecular epitopes for drug targeting.

Keywords: Activated platelets; Antibody-drug conjugate; Cancer; GPIIb/IIIa.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Animals
Antineoplastic Agents / administration & dosage*
Antineoplastic Agents / metabolism
Blood Platelets / metabolism*
Disease Models, Animal
Immunoconjugates / administration & dosage*
Immunoconjugates / metabolism
Mice
Molecular Targeted Therapy / methods*
Neoplasm Metastasis / drug therapy
Neoplasm Transplantation
Oligopeptides / administration & dosage*
Oligopeptides / metabolism
Platelet Glycoprotein GPIIb-IIIa Complex / immunology
Platelet Glycoprotein GPIb-IX Complex / immunology
Single-Chain Antibodies / immunology
Transplantation, Heterologous
Treatment Outcome
Triple Negative Breast Neoplasms / drug therapy*
Tumor Microenvironment*

Substances

Antineoplastic Agents
Immunoconjugates
Oligopeptides
Platelet Glycoprotein GPIIb-IIIa Complex
Platelet Glycoprotein GPIb-IX Complex
Single-Chain Antibodies
glycoprotein receptor GPIb-IX
monomethyl auristatin E