Journal: Cancer Chemotherapy and Pharmacology
Article Title: Preclinical pharmacokinetics, pharmacodynamics, and efficacy of RG7116: a novel humanized, glycoengineered anti-HER3 antibody
Figure Lengend Snippet: a Extended dosing study investigating seven i.v. weekly administrations of an efficacious dose (3 mg/kg) and a less-efficacious (0.3 mg/kg) dose of RG7116 in FaDu xenograft mice (FaDu_008). RG7116 given as a three-weekly cycle (two doses in total) was also investigated. b Dose-dependent efficacy up to Day 39 was seen as in the previous study and tumor growth inhibition with 3 mg/kg RG7116 given as a three-weekly cycle was similar to weekly dosing. Mice in the 0.3 mg/kg group were rechallenged ( black arrow ) with 5 mg/kg on Day 39 resulting in tumor growth inhibition for two further assessments; however, tumor regrowth was observed in all dosing groups from Day 50. c RG7116 trough concentrations from the first to third administrations again showed accumulation only with the higher dose. Inhibition of HER3 ( d ) and AKT ( e ) phosphorylation was also seen with weekly dosing at the efficacious dose (3 mg/kg) but not with the lower dose (0.3 mg/kg). Following a single 3 mg/kg dose (representing a three-weekly schedule), initial inhibition of HER3 phosphorylation was seen to diminish by Day 14 and 21. f Upregulation of HER1 (~2.1-fold) and HER2 (~1.3-fold) mRNA was seen 96 h after FaDu xenograft mice ( n = 5) were administered 1.0 mg/kg RG7116 in a separate study, and this was associated with upregulation of HER1 and HER2 protein. g To compare the single animals, 20 µg total protein lysate was loaded per lane (lanes 101–110 are vehicle and 201–210 are the RG7116-treated animals). At Day 52, inhibition of HER3 phosphorylation was maintained in RG7116-treated mice, and expressed HER1 was seen to be phosphorylated compared to vehicle control. HER2 and pHER2 were not changed (data not shown). SEM standard error of the mean, SD standard deviation
Article Snippet: Western Blot analyses Tissue was immediately lysed using Triton Lysis Buffer (1 % Triton-X-100; 10 µg/mL aprotinin; 0.4 mM orthovanadate; 1 mM phenylmethylsulfonyl fluoride), and lysates were denatured in NuPAGE Sample Reducing Agent at 70 °C for 10 min. SDS–PAGE and Western blotting were conducted as described previously [ ] using 20 μg protein per lane measured using a bicinchoninic acid assay and antibodies specific for HER1 (Upstate/Millipore, #06-847), HER2 (Dako, #A485), HER3 (clone C-17, Santa Cruz, #sc-285), phosphorylated HER1 (pHER1, clone ID Y39; Epitomics/Abcam, #ab32086), or pHER3 (clone 21D3 [Tyr1289 ], Cell Signaling Technologies, #4791).
Techniques: Mouse Assay, Inhibition, Standard Deviation