Optimising Cancer Therapeutics: An In Vitro and In Silico Approach

Abstract

Cancer is a major global health challenge, causing millions of new cases and deaths each year. It's complex, influenced by genetics, environment, and lifestyle, with the tumour microenvironment playing a key role. Treatments like surgery, radiation, and chemotherapy have limitations and side effects, due to the complexity and influence of genetics, environment, and lifestyle, with the tumor microenvironment playing a key role. Moreover, addressing disparities in cancer rates among ethnic groups is crucial for equitable healthcare. There are two pharmacokinetics principles that were utilised in this project: “Top-down” and “Bottom up”. For the “Top-down”- physiologically based pharmacokinetic modelling (PBPK) work, two tyrosine kinase inhibitors (TKIs) were investigated based on clinical studies: gefitinib and imatinib. Gefitinib can inhibit the epidermal growth factor receptor (EGFR) to treat non-small cell lung cancer (NSCLC), and it is removed by CYP 2D6 and 3A4. The ethnic differences between Caucasian and Chinese cancer populations were assessed. To explore the impacts of CYP 2D6’s phenotypes on Chinese cancer population group, a virtual Chinese cancer population group was developed, and multiple dose regimens were conducted and compared with the Caucasian cancer population group. CYP 2D6 phenotypes' effects on gefitinib plasma concentrations in Chinese cancer population was evaluated and demonstrated that for the two most prominent CYP 2D6 phenotypes within the Chinese population, namely EM and IM, a dose increase to 500 mg once daily would better target a suggested target trough concentration. Imatinib can inhibit BCR-ABL activity to treat gastrointestinal stromal tumours (GIST) and chronic myeloid leukaemia (CML). The normal trough plasma concentrations for imatinib in cancer patients is 750-1500 ng/mL. Due to the CYP 2D6 polymorphism, to receive better clinical outcomes within Chinese cancer patients, therapeutic drug monitoring (TDM) strategy was utilised to adjust imatinib trough plasma concentrations to observe the application results post adjustment, through implementation of the developed virtual Chinese cancer population. The commonly used dosing regimen for imatinib is 400–600 mg daily, for advanced disease, it can be used as 600-800 mg daily. Unlike Caucasian patients, Chinese patients are recommended with lower doses (600 mg/day) in clinical treatment to achieve effective plasma concentrations. For the “Bottom up”- the research focused on improving brain cancer treatment at the cellular level, exploring the inhibition effects of flavonoids on human brain tumour cells. The blood brain barrier (BBB) has been seen as the main obstacle for the treatment of brain cancers, because of its ability to prevent the entry and accumulation of the chemotherapeutic drugs. Firstly, the cytotoxic properties of selected flavonoids as natural compounds were evaluated by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay. Secondly, the modulating ability of selected flavonoids were tested by the H33343 and mitoxantrone intracellular accumulation assay, and the inhibition effects on the invasion and migration LN 229 cells were assessed by cellular migration assay. Through accumulation assay, 7-aminoflavone, 5-methoxyflavone showed better inhibition effects than KO143; harmine, trihydroxyethylrutin and rotenone indicated similar inhibition effects with KO143. Based on the migration assay, the impacts of these flavonoids on reactive oxygen species (ROS) level and the activation of caspases in LN 229 cells were evaluated to observe the ability associated with apoptosis. The migration increase level of harmine, and rotenone is below 10%, and the migration increase level of 7-methoxyflavanone is over 20%. Furthermore, 100 μM rotenone and 100 μM harmine are detected as the largest detection through ROS assay. Harmine and rotenone are considered as the promising compounds among the selected eight flavonoids, they had demonstrated their potential in their inhibition effects on LN229 cells, ability to regulate BCRP efflux function, induce ROS level increasing and the apoptosis.