Gv214

Overexpressing miR-499a and miR-con (Supplementary Table S3) was generated by plasmid transduction using GV214 (GeneChem Co., Ltd, Shanghai, China). MiR-449a antagomir (anti-miR-449a) and non-targeting sequence (negative control, anti-NC) (Supplementary Table S4) were synthesized (RiboBio, Guangzhou, China). SiRNA that target c-Myc and its negative control (NC) (Supplementary Tables S4) were purchased from Invitrogen (USA). For transfection, the cells were plated on an antibiotic free growth medium at 30–40% confluence approximately 24 h before transfection. Transfection was performed with Trans IT^®-2020 Transfection Reagent (Mirus Bio LLC, USA) according to manufacturer’s protocol. The medium was replaced with new culture medium 6 h after transfection.

Cells at the logarithmic phase of growth were trypsinized and then seeded in a six-well plate, at a density of 1 × 10⁵ cells per well. After routine culture for 24 h, the cells were transfected with miR-541-3p mimic, miR-NC, anti-miR-541-3p, and anti-NC (all synthesized by GenePhama, Shanghai, China) according to the instructions of Lipofectamine 2000 kits (Invitrogen, USA), and GV214 (GeneChem Co., Ltd, Shanghai, China). The full-length sequence of HSP27 or β-catenin was amplified by PCR and subcloned into the pcDNA3.1 vector (Invitrogen, USA) to generate oe-HSP27 or oe-β-catenin plasmid. The medium was replaced 6 h after transfection.