1640 medium 1640

Human liver cancer cell line SMMC-7721, Bel-7404, Huh7, HepG2 and normal liver cell HL-7702 cells were maintained in 1640 medium (1640; PAA Laboratories GmbH) supplemented with 10% FBS (PAA Laboratories GmbH). Forty paired hepatocellular carcinoma and adjacent nontumor liver tissues (located > 3 cm from the tumor) were collected from patients undergoing resection of hepatocellular carcinoma at our hospital. The relevant characteristics of the studied subjects were shown in Table S1. No systemic or local treatment had been received before operation. Both nontumor and tumor tissues were histologically confirmed. Informed consent was obtained from each patient and was approved by the Institute Research Ethics Committee at Cancer Center (The Fourth Hospital of Harbin Medical University).

Human breast cancer cell lines MCF-7 and ZR-75-1 were obtained from Genechem (Shanghai Genechem Co., Ltd., Shanghai, China). Both cell lines were identified by short tandem repeat analysis. MCF-7 cells were maintained in 1640 medium (1640; PAA Laboratories GmbH, Cölbe, Germany) supplemented with 10% FBS (Biological Industries, Cromwell, CT, USA), and ZR-75-1 cells were maintained in RPMI 1640 medium (PAA Laboratories GmbH) supplemented with 15% FBS (Biological Industries) and 1% Insulin, Transferrin, Selenium Solution (ITS-G; Gibco, Grand Island, NY, USA). The cells were cultured in a humidified 5% CO₂ incubator at 37 °C. To establish a stable MeCP2 knockdown cell line, MCF-7 cells were firstly transfected by Sh-MeCP2 or control lentivirus. After geneticin resistance screening, the two cell lines were additionally transfected by the luciferase reporter gene lentivirus to facilitate in vivo imaging experiments.

Paired GC and adjacent non-tumor gastric tissues were obtained from 36 patients who underwent surgical resection at the First Affiliated Hospital of Xi’an Jiaotong University and had not undergone previous surgery, radiotherapy, or chemotherapy. The tissue samples were immediately snap-frozen in liquid nitrogen until RNA extraction. Both tumor and non-tumor tissues were histologically confirmed. Informed consent was obtained from each patient, and the study was approved by the Institute Research Ethics Committee at Cancer Center, Xi’an Jiaotong University. Human GC AGS and MKN45 GC cell lines were obtained from the Cell Bank (Shanghai GeneChem Co., Ltd., Shanghai, China). The AGS and MKN45 cell lines were maintained in 1640 medium (1640; PAA Laboratories GmbH) supplemented with 10% fetal bovine serum (PAA Laboratories GmbH) and cultured in a humidified 5% CO₂ incubator at 37 °C. The cell lines were transfected with Lipofectamine 2000 (Invitrogen, Carlsbad, CA, USA) following the manufacturer’s protocol.