The impact of siRNA and GHS-R-specific peptide antagonist on early apoptosis of canine mammary carcinoma cells. (A) The effect of knock-down of growth hormone secretagogue receptor by siRNA and (B) GHS-R-specific peptide antagonist [D-Lys3]-GHRP6 (Peptides International) (1000 μM) on early apoptosis of CMT-W1M cell line assessed by the Annexin V/PI test (BD Bioscience, USA). The number of early apoptotic cells represented as a percentages of Annexin V stained cells (±SD) with intact cell membrane obtained with FACS Aria II (Becton Dickinson) highly significantly increased after a ghrelin inhibitor treatment (p < 0.01 marked as **) and significantly increased after siRNA treatment (p < 0.05 marked as *). The experiment has been conducted in three replicates. The statistical analysis was performed using Prism version 5.00 software (GraphPad Software, USA). One-way ANOVA followed by Tukey HSD post-hoc test and t-test were applied.