The intratumoral injection of anti-miR-221 and anti-miR-222 antagomirs into PC3-derived tumors reduces tumor growth and has long lasting effects on miR-221 and miR-222 endogenous expression.

<p>A Tumor growth curves depicting the average±SEM values of PC3 derived tumors injected either with a negative control antagomir (ctrl) or with a mixture of anti-miR-221 and anti-miR-222 antagomirs (anti-miR221/222). Each tumor was treated with three injections of 1 µg of each antagomir at days 0, 5, and 9 (arrows). Day 0 is the day of the first antagomir injection. Each mouse (n = 8) was bearing a negative control injected tumor on one flank, and an antagomir treated one on the controlateral flank. Data are presented as the means±SEM of two independent experiments. *, P = 0.009. B Average volume fold increase of the same tumors as in A. The data presented are the means±SEM, and represent the ratio between the volumes at the sacrifice (33 days from the first antagomir injection) and the volumes measured at the day of the first antagomir injection. *, P = 0.009. C Quantitative real-time PCR of miR-221 (upper panel) or miR-222 (lower panel) in tumors excised from four representative mice (A10, D3, D10, E3) at the day of sacrifice, 24 days after the last antagomir injection. The data are presented as the means±SD of three independent experiments, each performed in triplicate. *, P<0.05. The values presented are the miRNA expression fold changes, as compared to the expression detected in negative control tumors grown in each mouse, set as = 1. D Representative p27 Western blot analysis on total proteins extracted from the same tumors as in c. For each mouse, the proteins from the negative control tumor and the antagomir-treated tumor are shown. β-actin immunoreactivity is shown as a loading control. Under each lane, the numerical values represent p27 relative amount, that was set = 1 in each control tumor (ctrl), and the p27 expression in the respective controlateral anti-miR221/222 tumor was calculated.