Anti‐tumour effect of lapatinib in canine transitional cell carcinoma cell lines

Abstract

Transitional cell carcinoma (TCC) accounts for >90% of canine malignant tumours occurring in urinary bladder, and the prognosis is poor. Our previous study, using RNA sequencing, showed that human epidermal growth factor 2 (HER2) was the most activated upstream regulator related to carcinogenesis in canine TCC. The aim of this study was to examine the anti‐tumour effect of lapatinib, a tyrosine kinase inhibitor of HER2, on canine TCC cell lines in vitro and in vivo. Five canine TCC cell lines (TCCUB, Love, Sora, LCTCC, and MCTCC) were used. Western blotting showed that HER2 protein expression was observed in all of the canine TCC cell lines. Lapatinib inhibited phosphorylation of HER2 and cell growth in a dose‐dependent manner. Cell cycle analyses using flow cytometry showed that lapatinib significantly increased the sub‐G1 and G0/G1 phase fractions and significantly decreased the S and G2/M phase fractions in the cell lines (Sora and TCCUB). For the in vivo experiments, the canine TCC cells (Sora) were subcutaneously injected into nude mice. Six days after inoculation, lapatinib (100 mg/kg) or vehicle was administered daily via intraperitoneal administration for 14 days. Tumour volume was significantly smaller in the lapatinib group compared with the vehicle control group. Histologically, lapatinib significantly increased necrotic areas in the tumour tissues. These findings suggest that lapatinib exerts anti‐tumour effects on canine TCC cells by inhibiting HER2 signalling and inducing cell cycle arrest.

Aberrant expression of the COX2/PGE2 axis is induced by activation of the RAF/MEK/ERK pathway in BRAFV595E canine urothelial carcinoma

“…www.nature.com/scientificreports www.nature.com/scientificreports/ Methods Cell culture. Eight cUC cell lines, TCCUB, Sora, Love, Nene (originally established in our laboratory), NMTCC, LTCC, MCTCC and OMTCC (kindly provided by Hokkaido University) were used in this study 13,51,52 . Each cell line was maintained in RPMI-1640 supplemented with 10% heat-inactivated foetal bovine serum (FBS) and 5 mg/L gentamicin at 37 °C in a humidified atmosphere with 5% CO 2 .…”

Anti-tumor effects of the histone deacetylase inhibitor vorinostat on canine urothelial carcinoma cells

“…Three cUC cell lines, Sora, TCCUB, and Love were previously established in our laboratory and another three, NMTCC, MCTCC, and OMTCC, were kindly provided by Dr. Hoshino, Iwate University [24, 25]. The information of cell lines used in this study described in S1 Table.…”

Quantitative analysis of HER2 mRNA expression by RNA in situ hybridization in canine mammary gland tumors: Comparison with immunohistochemistry analysis

“…Recently, HER2-targeted cancer immunotherapy using recombinant Listeria monocytogenes, which expresses a chimeric human HER2/neu construct, was shown to prolong the overall survival and reduce metastasis rates in canine models of pediatric osteosarcomas [43]. Additionally, small-molecule tyrosine kinase inhibitor (lapatinib) of HER2, which may cross-react between species, exerted anti-tumor effects in canine transitional cell carcinoma cell lines [44]. Such comparative studies using canine models may not only facilitate individual therapeutic methods for dogs but are also applicable in understanding the pathogenesis of human cancers.…”