Kallistatin as an inhibitory protein against colorectal cancer cells through binding to LRP6

Abstract

Kallistatin (KL) is a member of the serine proteinase inhibitor (serpin) family regulating oxidative stress, vascular relaxation, inflammation, angiogenesis, cell proliferation, and invasion. The heparin-binding site of Kallistatin has an important role in the interaction with LRP6 leading to the blockade of the Wnt signaling pathway. In this study, we aimed to explore the structural basis of the Kallistatin-LRP6E1E4 complex using in silico approaches and evaluating the anti-proliferative, apoptotic, and cell cycle arrest activities of Kallistatin in colon cancer lines. The molecular docking showed Kallistatin could bind to the LRP6E3E4 much stronger than LRP6E1E2. The Kallistatin-LRP6E1E2 and Kallistatin-LRP6E3E4 complexes were stable during Molecular Dynamics (MD) simulation. The Molecular Mechanics/Poisson-Boltzmann Surface Area (MM/PBSA) showed that the Kallistatin-LRP6E3E4 has a higher binding affinity compared to Kallistatin-LRP6E1E2. Kallistatin induced higher cytotoxicity and apoptosis in HCT116 compared to the SW480 cell line. This protein-induced cell-cycle arrest in both cell lines at the G1 phase. The B-catenin, cyclin D1, and c-Myc expression levels were decreased in response to treatment with Kallistatin in both cell lines while the LRP6 expression level was decreased in the HCT116 cell line. Kallistatin has a greater effect on the HCT116 cell line compared to the SW480 cell line. Kallistatin can be used as a cytotoxic and apoptotic-inducing agent in colorectal cancer cell lines.

Communicated by Ramaswamy H. Sarma

Keywords:

• Kallistatin
• LRP6 protein
• human
• molecular dynamics simulation
• molecular docking
• cell survival
• apoptosis
• cell cycle checkpoints
• gene expression
• colorectal neoplasms

Authors’ contributions

Behzad Shahbazi: Conceptualization, Data Curation, Formal Analysis, Methodology, Writing – Original Draft Preparation, investigation. Ladan Mafakher: Data Curation, Methodology. Seyed Shahriar Arab: Supervision, Software. Ladan Teimoori-Toolabi: Conceptualization, Funding Acquisition, Project Administration, Validation, Writing – Review & Editing.

Availability of data

All data is available in the manuscript and supplementary materials.

Disclosure statement

The authors declare that no competing interests exist.

Additional information

Funding

This study was supported by Pasteur Institute of Iran (Grant Number: BB-9469). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.