Receptor tyrosine kinases as a therapeutic target by natural compounds in cancer treatment

Background

Receptor tyrosine kinases (RTKs) are single-pass transmembrane proteins that play significant roles in regulating cellular processes, including cell division and growth. Overexpression and mutations of RTKs have been found in clinical manifestations of different forms of cancer. Therefore, RTKs have received considerable interest as a therapeutic biomarker in the treatment of cancer cells.

Main body of the abstract

Comprehensive data on RTKs, pharmacological and biological properties of natural compounds were systematically searched up to 2021 using relevant keywords from various databases, such as Google Scholar, PubMed, Web of Science, and Scopus. The scientific search by various standard electronic resources and databases unveils the effectiveness of medicinal plants in the treatment of various cancers. In vitro and in vivo studies suggested that bioactive compounds such as flavonoids, phenols, alkaloids, and many others can be used pharmacologically as RTKs inhibitors (RTKI) either by competing with ATP at the ATP binding site of the tyrosine kinase domain or competing for the receptor extracellular domain. Additionally, studies conducted on animal models indicated that inhibition of RTKs catalytic activity by natural compounds is one of the most effective ways to block the activation of RTKs signaling cascades, thereby hampering the proliferation of cancer cells. Furthermore, various pharmacological experiments, transcriptomic, and proteomic data also reported that cancer cells treated with different plants extracts or isolated phytochemicals exhibited better anticancer properties with minimal side effects than synthetic drugs. Clinically, natural compounds have demonstrated significant anti-proliferative effect via induction of cell apoptosis in cancer cell lines.

Short conclusion

An in-depth knowledge of the mechanism of inhibition and structural characterization of RTKs is important to the design of novel and selective RTKIs. This review focuses on the molecular mechanisms and structures of natural compounds RTKI targeting vascular endothelial growth factor, epidermal growth factor receptor, insulin receptor, and platelet-derived growth factor while also giving future directions to ameliorate the scientific burden of cancer.

Graphic abstract

Computational Evaluation of Bioactive Compounds from Colocasia affinis Schott as a Novel EGFR Inhibitor for Cancer Treatment

INTRODUCTION

Epidermal growth factor receptor (EGFR) is a transmembrane protein that belongs to the ErbB/HER-family of tyrosine kinase receptors. Somatic mutations and overexpression of EGFR have been reported to play a vital role in cancer cell development and progression, including cell proliferation, differentiation, angiogenesis, apoptosis, and metastatic spread. Hence, EGFR is an important therapeutic target for the treatment of various types of epithelial cancers. Somatic mutations have led to resistance to clinically approved synthetic EGFR inhibitors. Furthermore, synthetic EGFR inhibitors have been associated with several side effects. Thus, there is a need to develop novel EGFR inhibitors with an acceptable biosafety profile and high efficacy.

METHODS

Herein, we employed structural bioinformatics and theoretical chemistry techniques via molecular docking, molecular mechanics generalized Born surface area (MM-GBSA) calculation, density functional theory analysis (DFT), and pharmacokinetic study to identify novel EGFR inhibitors.

RESULTS

The stringent molecular docking and MM-GBSA calculations identified MET 793, LYS 745, PHE 723, ASP 855, ARG 411, and THR 854 as principal amino acid residues for EGFR-ligands interactions. Furthermore, Colocasia affinis Schott compounds exhibited higher binding energy and more stable interactions than the reference compound (gefitinib). DFT analysis also ascertains better bioactivity and chemical reactivity of C. affinis Schott with favorable intramolecular charge transfer between electron-donor and electron acceptor groups. The pharmacokinetic profile of C. affinis Schott bioactive compounds satisfies Lipinski's rule of five assessment.

CONCLUSION

Collectively, C. affinis Schott compounds demonstrated higher inhibitory potentials against EGFR and better pharmacological properties when compared with gefitinib. C. affinis Schott compounds are therefore suggested as promising therapeutic EGFR inhibitors for cancer treatment.