17βHSD1 expression and activity in NSCLC cell lines. (a) mRNA expression of 17βHSD1 and (b) 17βHSD2 enzymes. Positive control, MCF-7 cells. (c) E2 production via intratumoral 17βHSD1 activity and intratumoral aromatase activity on 24hrs of treatment with either E1 or testosterone, respectively. (d) Expression of 17βHSD1 following aromatase inhibitor treatment. (e) 17βHSD1 siRNA assisted 17βHSD1 knockdown after 72hrs of siRNA treatment. siRNA-C: scramble siRNA; siRNA1: 17βHSD1 specific siRNA1 and siRNA2: 17βHSD1 specific siRNA2. (f) Proliferation after 72hrs of treatment with either with E1 and/or 17βHSD1 specific siRNA. Data represent 3 independent experiments, each performed in triplicate. Results are represented as mean ± SD. All immunoblots are representative of 3 independent experiments.