Cytotoxic Effects of the Dual ErbB Tyrosine Kinase Inhibitor, Lapatinib, on Walker 256 Rat Breast Tumour and IEC-6 Rat Normal Small Intestinal Cell Lines

Abstract

Lapatinib is an orally administered, dual ErbB1/ErbB2 tyrosine kinase inhibitor (TKI). It is effective in ErbB2 + ve breast cancer treatment. However, lapatinib is associated with diarrhoea with an incidence of 47-75%. The mechanism of ErbB1 TKI-induced diarrhoea remains unclear. ErbB1 or epidermal growth factor receptor (EGFR) is expressed in gastrointestinal mucosa whereby the primary site for drug absorption is intestine. Thus, administration of ErbB1 oral TKI may disrupt gut homeostasis, leading to diarrhoea. Nevertheless, further investigations are required. We observed that lapatinib inhibited 50% Walker 256 breast tumour cells and IEC-6 small intestinal cell growth. Higher percentage of necrosis was observed in lapatinib-treated Walker 256. Lapatinib-treated IEC-6 showed higher percentage of late apoptosis. Only ErbB2 mRNA was detected in Walker 256 but both ErbB1 and ErbB2 mRNAs were detected in IEC-6, yet both protein staining were detected in both cells. Lapatinib exhibited cytotoxic properties on ErbB1/ErbB2 expressing cell lines, with intestinal cells being more sensitive to lapatinib compared to tumour cells. Lapatinib induced necrosis in tumour cells, while inducing late apoptosis in intestinal cells may explain lapatinib-induced diarrhoea in patients administered with the drug which could be due to apoptosis of intestinal epithelial cells leading to barrier disruption and consequently diarrhoea.

Mechanism and treatment of diarrhea associated with tyrosine kinase inhibitors

“…Direct inhibition of EGFR by TKIs may reduce the growth and healing of the intestinal epithelium, cause mucosal damage, and lead to diarrhea. This hypothesis was supported by an in vitro experiment showing that lapatinib inhibits growth and induces late apoptosis in normal intestinal epithelial cells (IEC-6), and has stronger toxicity in IEC-6 cells than in breast tumor cells [ 11 ]. Moreover, lapatinib is associated with diarrhea in rats; this is caused by a reduction in EGFR expression in jejunal crypts and dose-dependent changes in crypt length, mitotic rate, and goblet cell morphology [ 12 ].…”

Ai-Tong-An-Gao-Ji and Fisetin Inhibit Tumor Cell Growth in Rat CIBP Models by Inhibiting the AKT/HIF-1α Signaling Pathway

“…The Walker 256 breast cancer cell line was selected using 89% high glucose medium containing various amino acids and glucose (H-DMEM, High glucose Dulbecco's Modified Eagle Medium) + 10% fetal bovine serum (FBS) + 1% penicillin/streptomycin (P/S) [ 17 ].…”

Lapatinib-induced ErbB1 Inhibition Modulates Caco-2 Intestinal Permeability Through Tight Junction Alteration

“…Several hypotheses have been explored to understand LID. Prominent theories, based on research conducted in preclinical models, involve changes in chloride secretion, histopathological changes in the gastrointestinal tract (GIT), changes in gut micro ora, and, most notably, the inhibition of ErbB1 in the gastrointestinal (GI) mucosa [10][11][12][13][14] . As ErbB1 is primarily expressed in the GI mucosa 15 , it was hypothesised that ErbB1 inhibition by lapatinib might disrupt normal GI function, resulting in diarrhoea.…”