AT-MSCs affect chemoresistance to 5FU in the direct cocultures with SKBR3 cells. A) AT-MSCs were directly cocultured with EGFP-SKBR3 in the presence or absence of 6.25 ng/ml - 1 μg/ml 5FU for 6 days. Relative viability of EGFP-SKBR3 was determined by fluorescence measurements. The presence of the AT-MSCs did not interfere with the fluorescence signal. AT-MSCs significantly decreased the resistance to 12.5 ng/ml and 50 ng/ml 5FU. IC50 shifted from IC50(SKBR3) = 70 ng/ml 5FU to IC50(SKBR3 in MSCs-CM) = 35 ng/ml 5FU, *p < 0.05. B) AT-MSCs significantly increased Caspase3/7 activation in SKBR3 cells in response to 5FU treatment for 48 hrs. No Caspase 3/7 activity was induced in AT-MSCs cell under these conditions due to their inherent chemoresistant nature, *p < 0.05. C) AT-MSCs did not significantly affect sensitivity of tumor cells to cis-platin treatment. Data were derived from the three independent experiments performed in quadruplicates. Values were expressed as means ± SD, p > 0.05.