This negated any effects from inherent SGS absorption as all the SGSs were contained at the bottom of the discarded well. Absorbance was interpreted at 450 nm for each well using a SPECTROstar Nano plate reader (BMG Labtech Inc.). LDH assay SNU449 and HEP3B cells PXD101 were exposed to various concentrations of SGSs (0.1, 1.0, 10.0, and 100 μg/ml) for 24, 48, and 72 h,
and the cell-free supernatant was removed. Maximum LDH selleck chemical release was obtained by exposing the cells to a 2% Triton-X 100 solution to permeabilize the membranes. LDH activity was determined by the use of a cytotoxicity detection kit purchased from Roche Applied Science (Indianapolis, IN, USA). Aliquots of the cell culture media from the SGS-exposed samples, untreated samples,
and the permeabilized samples were added to a 96-well plate, and an equal volume of LDH cytotoxicity detection reagent was added. The 96-well plates were read on a spectrophotometer, and the absorbance at 492 nm was measured. Calculations were performed as per the recommendations of the kit. To show that SGS does not interfere with the kit, cells were permeabilized with a 2% APO866 Triton-X 100 solution. The lysate was incubated with various concentrations of SGS for 24 h. No difference was observed for any of the control samples indicating that SGSs do not interfere with the assay. Flow cytometry Viability was measured with flow cytometry (LSRII, BD Biosciences, Franklin, NJ, USA) as described previously . Briefly, cell media was aspirated, and the adherent cells were collected after trypsinization. Each sample was washed and stained with annexin V-FITC and propidium iodide (PI) without fixation or permeabilization. Annexin V is a protein that binds to phosphatidylserine, which is externalized
in apoptotic cells. Propidium iodide fluoresces when it is bound to DNA in membrane-damaged cells. Cells that were negative for both markers were characterized as viable. Approximately 50,000 events were measured for each sample. Due to sample availability, only one time point (24 h) was measured on one cell line (SNU449) at two concentrations (10 and 100 μg/ml). As such, these VEGFR inhibitor data have been placed in the Additional file 1. Real-time optical bright-field microscopy Hep3B cells were cultured in glass bottom (no. 1.5) 24-well plates purchased from MatTek Corporation (Ashland, MA, USA). After overnight incubation, the cells formed non-confluent monolayers. The 24-well plate was placed in an incubator enclosing a 1X81 Olympus microscope (Center Valley, PA, USA) equipped with a DSU Confocal Attachment and a ×60 oil immersion objective. The cells were allowed to equilibrate with the incubator environment (37°C, 5% CO2) before adding pre-warmed SGSs and acquiring images. Eight Z-plane images were acquired with a gap of 1 μm every 15 min. A typical experiment comprised of 10 to 15 waypoints.