FIGURE 2.

A minority subpopulation increases non-autonomous miR-21 activity in adenocarcinoma cells. a, BxPC3^miR21 (doxycycline-inducible miR-21) or irrelevant miRNA (BxPC3^miRN/S) controls were directly cocultured with miR-21 reporter cells (BxPC3^CkmiR21) at the indicated ratios (±1 μg/ml doxycycline). Renilla luciferase luminescence (levels decreased by miR-21) was normalized to firefly luciferase luminescence to allow quantitative comparison (relative luminescence units (RLU)). Doxycycline-induced BxPC3^miR21 activation increased miR-21 activity in BxPC3^CkmiR21 reporter cells. Coculture of BxPC3^CkmiR21 with BxPC3^miRN/S had no effect on normalized Renilla activity in BxPC3^CkmiR21. Indirect coculture was insufficient to induce non-autonomous miR-21 activity. The first white column indicates BxPC3^CkmiR21 in standard monoculture. *, p < 0.05 versus BxPC3^miR21 + BxPC3^CkmiR21, no doxycycline by multifactorial analysis of variance, n = 4. b, representative Western blot analysis of SIDT1 expression in pancreatic adenocarcinoma (BxPC3, MIAPaCa2, and Capan2) and immortalized normal ductal epithelial cells (HPDE4), demonstrating differential expression of SIDT1. Densitometric quantification (means ± S.D. (error bars)) of SIDT1 signal, normalized to that of β-actin. Shown are mean values ± S.D. (n = 3). AU, arbitrary absorbance units.