The Recombinant Protein Based on Trypanosoma cruzi P21 Interacts With CXCR4 Receptor and Abrogates the Invasive Phenotype of Human Breast Cancer Cells.

Bruna Cristina Borges,Claudio Vieira Da Silva,Marcelo José Barbosa Silva,Patrícia De Castilhos,Samuel Cota Teixeira,Felipe Andrés Cordero Da Luz,Isadora Akemi Uehara,Mylla Spirandelli Da Costa,Flávia Alves Martins,Daiana Silva Lopes,Ana Flávia Oliveira Notário,Fernanda Carvalho De Souza,Marlus Alves Dos Santos,Álvaro Ferreira Junior,Thaise Lara Teixeira

doi:10.3389/fcell.2020.569729

Abstract

Trypanosoma cruzi P21 is a protein secreted by the parasite that plays biological roles directly involved in the progression of Chagas disease. The recombinant protein (rP21) demonstrates biological properties, such as binding to CXCR4 receptors in macrophages, chemotactic activity of immune cells, and inhibiting angiogenesis. This study aimed to verify the effects of rP21 interaction with CXCR4 from non-tumoral cells (MCF-10A) and triple-negative breast cancer cells (MDA-MB-231). Our data showed that the MDA-MB-231 cells expressed higher levels of CXCR4 than did the non-tumor cell lines. Besides, cytotoxicity assays using different concentrations of rP21 showed that the recombinant protein was non-toxic and was able to bind to the cell membranes of both cell lineages. In addition, rP21 reduced the migration and invasion of MDA-MB-231 cells by the downregulation of MMP-9 gene expression. In addition, treatment with rP21 blocked the cell cycle, arresting it in the G1 phase, mainly in MDA-MB-231 cells. Finally, rP21 prevents the chemotaxis and proliferation induced by CXCL12. Our data showed that rP21 binds to the CXCR4 receptors in both cells, downregulates CXCR4 gene expression, and decreases the receptors in the cytoplasm of MDA-MB-231 cells, suggesting CXCR4 internalization. This internalization may explain the desensitization of the receptors in these cells. Thus, rP21 prevents migration, invasion, and progression in MDA-MB-231 cells.

Highlights

Triple-negative breast cancer (TNBC) is characterized by a tumor subtype void of hormone receptors, such as the estrogen receptors (ER), progesterone receptors (PR), and human epidermal growth factor receptor 2 (HER2) (Zhou et al, 2018); this tumor is associated with poor prognosis (Den Brok et al, 2017)
As long as the cell lines expressed CXCR4, we addressed the ability of the rP21 protein to bind to the plasma membranes of these cell lineages
Calreticulin, is a calciumbinding protein from T. cruzi that can inhibit the activation of the complement cascade system favoring infection, besides the antiangiogenic activity and antitumor properties in vivo (Valck et al, 2010; Ramírez et al, 2012)

Summary

Introduction

Triple-negative breast cancer (TNBC) is characterized by a tumor subtype void of hormone receptors, such as the estrogen receptors (ER), progesterone receptors (PR), and human epidermal growth factor receptor 2 (HER2) (Zhou et al, 2018); this tumor is associated with poor prognosis (Den Brok et al, 2017). The CXCR4/CXCL12 axis can promote tumor metastasis by mediating cell invasion and proliferation and enhancing tumor-associated neoangiogenesis (Cojoc et al, 2013). It is involved in orientating cancer cell migration to metastasis sites, increased survival of cancer cells in suboptimal conditions, and the establishment of a tumor-promoting cytokine/chemokine network (Balkwill, 2004). This receptor is expressed constitutively in a wide variety of normal tissues, including lymphatic tissues, thymus, brain, spleen, stomach, and small intestine, but it is expressed in several types of tumor cells (Balkwill, 2004). Tumor cells increase the CXCR4 levels and CXCL12 production, transmitting autocrine and paracrine signals, leading to enhanced tumor growth and metastasis (Liekens et al, 2010)

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