Raja Nur Firzanah Syaza Raja Sharin, Wan Nor I’zzah Wan Mohamad Zain*, Jesmine Khan and Mohamad Johari Ibahim
Keywords: Caco-2 cell line, intestinal monolayer, in vitro model, lapatinib, gut permeability
Abstract: Oral route is one of the best minimally invasive methods for drug administration since it allows incorporation of nutrients and other exogenous molecules. In oral route, the small intestine is the main organ where the drug absorption occurs. Lapatinib is an oral administered drug, effective for ErbB2-positive breast cancer treatment however it is associated with adverse effects, including diarrhoea. Although diarrhoea can be tolerated, it can cause treatment interruption as well as reduce patients’ compliance. The underlying mechanism of lapatinib-induced diarrhoea remains unclear. Understanding the pathophysiology of the drug or substances through systemic absorption will usually be followed by testing the intestinal permeability. However, acquiring human intestinal permeability data would be extremely complicated and ethical. Development of a reliable human in vitro model of gastrointestinal barrier will provide an opportunity to better understand the cellular and molecular aspects of drug treatment, which at the same time provide a faster and more economical alternative to animal model. In this innovation study, Caco-2, a colon adenocarcinoma cell line was selected to study the possible lapatinib-induced diarrhoea mechanism since it has the ability to differentiate into enterocytes-like phenotype and able to form high barrier integrity. Therefore, Caco-2 would serve as an excellent in vitro model to study the intestinal absorption of lapatinib. Caco-2 cells were seeded in a semipermeable insert for 21 days to form an intestinal epithelial monolayer. The formation and integrity of intestinal monolayer were evaluated by measuring transepithelial electrical resistance (TEER) and the monolayer morphology was confirmed by scanning electron microscopy (SEM). From the results, Caco-2 grown in the semipermeable insert until day-19 is able to differentiate into microvillus-like structure with established integrity. Besides, Caco-2 cell monolayer also showed optimum resistance on day-19 at 810.74 ± 243.16 ohms/cm² suggesting high barrier integrity. As such, establishment of Caco-2 monolayer can be a promising tool to investigate the underlying mechanism of diarrhoea induced by lapatinib.
