<p><b>A.</b> Protein expression of the sulfatase modifying factor (SUMF)-1 was not reduced by hypoxia (10% O<sub>2</sub>×4 h) in the BEC or the NCM460 cells. <b>B.</b> Knockdown by siRNA for SUMF-1 effectively reduced the protein expression measured by ELISA in the NCM460 cells. <b>C.</b> ARSB activity was significantly reduced by siRNA for SUMF-1 (p<0.001), and additional reduction occurred in association with hypoxia (10% O<sub>2</sub>×4 h) (p<0.001) in the NCM460 cells, consistent with a requirement for both SUMF-1 and molecular oxygen for maximum ARSB activity. [ARSB = arylsulfatase B; BEC = bronchial epithelial cell].</p
