Figure 1
From: Parathyroid-hormone-related protein signaling mechanisms in lung carcinoma growth inhibition
Effect of PTH1R knockdown on H1944 proliferation. a Stable transduction of PTHrP-positive cells with shRNA lentiviral particles directed against PTH1R (open bars) resulted in 55–70% knockdown of the protein compared to levels in cells transduced with NTC particles (closed grey bar). b The PTH1R knockdown clones demonstrated increased proliferation (open circles) measured by MTS assay compared to NTC clones (closed circles). N = 3 clones for each group. Error bars are smaller than the symbol for some points and may not be visible. **P < 0.01 vs. NTC cells at each time point. c Treatment with exogenous PTHrP 1–34 for 1–5 days decreased H1944 cell proliferation in a dose-dependent fashion. The six columns at each time point represent increasing PTHrP concentrations of 0, 10−11, 10−10, 10−9, 10−8, and 10−7 M. The reduction at the largest dose of 10−7 M was about 25%. Data are replicates of 8 cell wells per day and PTHrP concentration. Similar results were obtained in multiple independent experiments (§P < 0.001). d In PTHrP-null H1944 cells, stable shRNA transduction resulted in 75–90% knockdown of PTH1R (open bars) compared to levels in NTC control clones (grey bars). e When PTH1R was intact (NTC group), treatment with exogenous 100 nM PTHrP 1–34 (closed grey bars) inhibited proliferation of wild type H1944 cells by 25–50% compared to cells treated with the PTHrP vehicle (open bars) (§P < 0.001). However, exogenous PTHrP 1–34 had no effect on growth rate in clones after stable knockdown of PTH1R. Comparison of the open bars between PTH1R knockdown clones and NTC clones demonstrates that reduction in PTH1R expression increased proliferation even in the absence of exogenous PTHrP 1–34. §P < 0.001.