TDK conference 2015

Anticancer drug research requires suitable cell model systems to accurately screen and develop new treatment options capable of acting against tumour growth and metastasis. Currently the most suitable models are live animals, however nowadays, due to animal welfare and protection concerns, other potential replacement methods are being explored to minimise the use of live animals in pharmaceutical research. In 3D or multilayer in vitro cell cultures cells can produce their own extracellular matrix, which can influence the uptake and transport of drugs, thus better mimicking the in vivo conditions than the widely used monolayer cell culture systems.

Our goals in the experiments were to characterise the cells' viability using MTS assay, and the size and cell numbers of the spheroids. We used non-specific AEBSF and specific matriptase inhibitors such as MI-432, MI-453, MI-460 and MI-463 at a concentration of 50 uM, and a matriptase inducer, suramin, at concentrations of 50, 100 and 200 uM. During our research, we used three different cell lines- a porcine neonatal non-tumorigenic jejunal cell line, IPEC-J2, a murine colonic adenocarcinoma cell line, C-26 and a human colon adenocarcinoma cell line, HT-29.

It was found that matriptase inhibitors did not cause cell death to a significant degree. However, suramin treatments lead to a dose-dependent reduction of cell viability at 100 and 200 uM in C-26 and HT-29 spheroids, and in IPEC-J2 cell monolayers as well.

IPEC-J2 cells formed smaller sized loose cell aggregates. In contrast, the other two cell lines formed solid spheroids with diameters of approximately 200 um for C-26 and 250-300 um for HT-29 after a growth period of 3 days. We found the control spheroids (formed from the cell lines C-26 and HT-29) grew in an exponential rate during the total 7 day spheroid growth period. Matriptase inhibitors at a concentration of 50 uM did not alter the HT-29 spheroid growth rate within 7 days. In contrast, MI-432 caused a remarkable decrease in C-26 spheroid growth. Suramin induced cellular detachment from the 3D spheroids, which can be attributed to its cytotoxic cell properties.

In conclusion, we used spheroids as part of a scientific system to investigate and evaluate potential anticancer properties of matriptase modulating drug candidates as well as to monitor the cancer cells' growth tendency during tumour cell attachment and formation in vitro when the cells had altered matriptase activity.