Figure 2. Intracellular content of hypotaurine affects the growth of U251.

250μM homocysteic acid resulted in a 5% decrease in cell amount A., a 48% decrease in intracellular hypotaurine B. and a 25% decrease in intracellular taurine C. Media supplemented with 200μM cysteamine results in a 12% increase in cell amount D. a 7-fold intracellular hypotaurine increase E. and unappreciable intracellular taurine change F. 45μM taurine leads to a 13% decrease in cell amount G. a 52% decrease in intracellular hypotaurine H. and a 7% increase in intracellular taurine I. Cell amount was given as mean±s.d. (n=8) and were determined by OD₄₅₀ after incubated with WST-1. Intracellular hypotaurine and taurine concentrations were given as μg/ml/(g cell dry weight) obtained through at least 3 biological and 3 technical replicates. J. Relative ADO gene expression of ADO gene silenced cell line (ΔADO) and the vector control cell line (VCT). A 45% decrease of ADO gene expression in ΔADO cells was observed (n=4). K. Compared to VCT cells, intracellular hypotaurine of ΔADO cells decreased by approximately 38% (n=6). L. Growth properties of ΔADO cells with different hypotaurine content in the media. VCT cells cultured without additional hypotaurine were used as controls. 100 μM hypotaurine in media led to growth rescue in ΔADO cells (n=8). Data was processed by two-way ANOVA.