Matrix gel

The cell migration and invasion assays were performed as previously described.¹⁷, ¹⁸ For the migration assay, HT29 or SW480 cells in serum‐free medium were seeded into a 24‐well Insert System with an 8‐μm pore size polyethylene terephthalate membrane (BD Biosciences). Complete medium was placed in the lower chambers. For the cell invasion assay, HT29 or SW480 cells in serum‐free medium were seeded into the chambers precoated with a matrix gel (BD Biosciences). Cells that had migrated or invaded through the membrane were fixed using 10% methanol, stained with 0.1% crystal violet, and quantified using a light microscope (Olympus). Migrated and invasive cells were counted from 5 randomly selected fields of each sample.

We performed cell invasion and migration experiments using Transwell chambers with or without matrix gel (BD Biosciences, San Jose, CA, USA). After transfection, the cells were seeded in the upper chamber of the Transwell, and the lower chamber was filled with medium containing 20% FBS. After incubation for 48 h in the chamber, the cells on the upper and lower chambers were fixed with 4% paraformaldehyde solution, stained with 0.1% crystal violet staining solution, and photographed under a microscope. The number of migrated or invaded cells was calculated using ImageJ software.

For the wound healing assay, cells were seeded with 10% fetal bovine serum culture until 80% confluent in 6-well plates. Then A2780 and SKOV3 cells were transfected with pcDNA3.1 or pcDNA3.1-LINC00152 while CAOV3 and ES-2 cells with either siControl or siLINC00152 siRNAs for 24 h. Then Cells were scraped off using a pipette tip and washed softly with PBS twice to remove the floating cells and debris. After washed by PBS, the cells were incubated with serum-free culture for 24 h to minimize the interference of cell proliferation. Representative images of cells migrating into the wounds were captured at 0 and 24 h in the same wounded region.
The Transwell assay was used to assess cell invasion (Corning Co. Ltd., USA). The lower chambers were pre-coated with 100 μL Matrix gel (#354234, BD Bioscience, USA) for 30 min. 24 h after transfection, cells were seeded on the upper chamber at 3.0 × 10⁴/well in serum-free medium to minimize the interference of cell proliferation. Medium containing 20% fetal bovine serum medium was applied to the lower chamber as chemo-attractant. After 24 h incubation at 37° C, cells which invaded through the Matrix gel and adhered to the lower surface of the filter were fixed with ethanol, stained with 0.5% crystal violet, photographed at 200×, and counted at 400× in 10 different fields to determine the average number of cells (BX51, Olympus, Japan).