Platelet P2Y12 Is Involved in Murine Pulmonary Metastasis

Yanhua Wang,Yueping Sun,Junling Liu,Lin Zhang,T Kent Gartner,Yong Zuo,Kemin Wang,Ding Li,Vladimir V Kalinichenko

doi:10.1371/journal.pone.0080780

Yanhua Wang, Yueping Sun + Show 7 more

Open Access

https://doi.org/10.1371/journal.pone.0080780

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Journal: PloS one	Publication Date: Nov 13, 2013
Citations: 83	License type: CC BY 3.0

Affiliation: Shanghai Jiao Tong University, University of Memphis

Abstract

The involvement of platelets in tumor progression is well recognized. The depletion of circulating platelets or pharmacologic inhibitors of platelet activation decreases the metastatic potential of circulating tumor cells in metastasis mouse models. The platelet ADP receptor P2Y12 amplifies the initial hemostatic responses activated by a variety of platelet agonists and stabilizes platelet aggregation, playing a crucial role in granule secretion, integrin activation and thrombus formation. However, the relationship between P2Y12 and tumor progression is not clear. In our study, the Lewis Lung Carcinoma (LLC) spontaneous metastatic mouse model was used to evaluate the role of P2Y12 in metastasis. The results demonstrated that P2Y12 deficiency significantly reduced pulmonary metastasis. Further studies indicated that P2Y12 deficiency diminished the ability of LLC cells to induce platelet shape change and release of active TGFβ1 by a non-contact dependent mechanism resulting in a diminished, platelet-induced EMT-like transformation of the LLC cells, and that transformation probably is a prerequisite of LLC cell metastasis. Immunohistochemical analyses indicated an obvious P2Y12 deficiency related attenuation of recruitment of VEGFR1+ bone marrow derived cell clusters, and extracellular matrix fibronectin deposition in lungs, which presumably are required for pre-metastatic niche formation. In contrast to the LLC cells, non-epithelial melanoma B16 cells induced platelet aggregation in a cell number and P2Y12-dependent manner. Also, a platelet induced EMT-like transformation of B16 cells is dependent on P2Y12. In agreement with the LLC cell model, platelet P2Y12 deficiency also results in significantly less lung metastasis in the B16 melanoma experimental metastasis model. These results demonstrate that P2Y12 is a safe drug target for anti-thrombotic therapy, and that P2Y12 may serve as a new target for inhibition of tumor metastasis.

Highlights

The involvement of platelets in tumor progression and metastasis in mouse models has been recognized for decades [1,2]
P2Y12−/− and littermate control WT mice were used for the evaluation the effects of P2Y12 on tumor progression in the spontaneous pulmonary metastasis mouse model
B16 melanoma cells could directly interact with WT platelets and cause them to aggregate in a manner that is dependent on both P2Y12 and the number of B16 cells

Summary

Introduction

The involvement of platelets in tumor progression and metastasis in mouse models has been recognized for decades [1,2]. The depletion of circulating platelets, or pharmacologic inhibitors of platelet activation decrease the metastatic potential of circulating tumor cells in mouse models of experimental metastasis [3,4,5]. Platelet receptors, such as GPIb/IX/V, Pselectin and integrin αIIbβ, can promote the progression and metastases of various types of tumors, and are potential targets for further clinical study [6,7,8]. Several studies suggested that thrombophilia caused by pro-coagulant mediators released in response to tumors may protect from external expansion and cancer dissemination [15], and deficiency of certain platelet surface receptors even resulted in enhanced experimental tumor metastasis [16]

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