DESIGN AND ACTIVITY STUDY OF XANTHINE DERIVATIVES AS DRUG CANDIDATE OF NON-SMALL CELL LUNG CANCER (NSCLC)

• Main Author: Amelia, Tasia
• Format: Dissertations
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/72694
• Institution: Institut Teknologi Bandung

Lung cancer has the highest prevalence among all cancers, and the incidence and death cases continue to rise every year, reaching 2.2 million and 1.8 million in 2020, respectively. Approximately 85% of the cases are Non-Small Cell Lung Cancer (NSCLC), and the majority are diagnosed at an advanced stage, and therefore survival rate for NSCLC patients remains quite low. According to epidemiological studies performed by the Surveillance, Epidemiology, and End Results (SEER) program, only 17.4% of lung cancer patients live for 5 years or more. Conventional therapy in the form of the inhibitor of Epidermal Growth Factor Receptor (EGFR), which are overexpressed in NSCLC, has been used clinically, but has no significant impact on increasing the patient survival. This is due to the lack of effectiveness of tyrosine kinase inhibitors caused by resistance of lung cancer patients with mutated EGFR tyrosine kinase domain (EGFR-TK), especially in exon 19 and 21. This occurrence of resistance becomes an urgency for the development of new tyrosine kinase inhibitors with good effectiveness on wildtype and mutated EGFRs to be able to replace the previous inhibitors and improve the success of treatment of lung cancer patients. The use of compounds with non-quinazoline heterocyclic ring is expected to overcome the problems of quinazoline inhibitors in interacting with mutated receptors, inhibiting the EGFR-TK, inhibiting cell proliferation and cell growth, and stimulating apoptosis of the cancer cell. Caffeine is known to inhibit estrogen receptors, which have a comparable structure to EGFR, so developing substances with xanthine nuclei has the potential to provide receptor inhibitory activity. The purpose of this study is to study the interaction of xantin compounds against EGFR-TK to obtain potential to be used as the inhibitor of EGFR-TK in wild-type form by in silico method, followed by the in vitro assay to obtain IC50 data against lung cancer cells, to obtain interaction data of the compounds against EGFR with well-known mutations using in silico method, and to predict the novel mutations that may cause resistance to the inhibitor. The research was carried out in several stages, starting with the selection of molecules with xanthine scaffold that may have the ability to become inhibitors of EGFR-TK using in silico method. This research employed a total of 40 xanthine derivatives. An interaction analysis was performed on wild-type EGFR-TK by comparing the results with clinically used tyrosine kinase inhibitors, namely gefitinib, erlotinib, and afatinib. According to the result, compounds 8, 12, 17, 20, and 37 have the best affinity as measured by the most negative binding free energy and the most chemical interaction occurred when compared to the others, whereas compound 20 was designed based on the compound 12 structure. Compound 8, 17, and 37 interacted with the residues in ATP binding site with hydrogen bond with Met793 as the primary chemical interaction, while 12 and 20 bind to the allosteric site of the receptor and formed hydrogen bond to Asp855, the same interaction found in EAI001, the fourth-generation allosteric inhibitor. This result was confirmed by cytotoxicity assay on A549 lung cancer cells to determine the IC50 value of several test compounds. Compound 17 showed the best result with an IC50 value of 317.7 ?M, which was 2.4 times higher than gefitinib as the reference compound. Compound 8, 37, and 38 showed IC50 values of 447.6, 1,763, and 2,446 ?M, correspondingly. The following interaction study against EGFR-TK with mutations commonly found in lung cancer patients (L858R/T790M/C797S) was performed to determine the ability of the compounds to bind to both receptors. The three reference compounds showed good binding ability, with compounds 8, 12, 17, and 20, providing the best results with more negative differences in the binding free energy value when compared to the wildtype EGFR-TK with comparable binding modes to the inhibitors. As a result, the four compounds can be considered as potential candidates for EGFR-TK inhibitors in both wildtype and mutated forms. Mutation prediction studies were also performed to identify mutations in the EGFR-TK binding site that have the potential to induce resistance to widely used inhibitors using molecular dynamics simulations for 200 ns. In this study, two types of ligands were used: ATP analogue as a native ligand of EGFR-TK and erlotinib as a tyrosine kinase inhibitor. The findings indicate that substituting Gly779, Glu791, Ile853, and Asp855 with alanine can improve the ATP affinity while decreasing erlotinib binding ability. Furthermore, replacing Glu762, the amino acid that forms salt bridges with Lys745, with alanine can eliminate the ability of ATP to bind to the receptor, enabling receptor deactivation.