Beas 2b

Human lung cancer cell lines (A549, H1299, PC9, H292, H1975) and human bronchial epithelial cell lines (Beas-2B) were purchased from the National Collection of Authenticated Cell Cultures (https://www.cellbank.org.cn, Shanghai, China). Cells were cultured in RPMI-1640 or F-12K medium (HyClone, Beijing, China) containing 10% fetal bovine serum (Ausbian, Australia) at 37 °C and 5% CO₂, according to manufacturer’s instructions.

Human normal lung epithelial cells (BEAS-2B) and LUAD cells A549 and H460 were purchased from the National Collection of Authenticated Cell Cultures. The above cells were cultured in RPMI-1640 medium supplemented with 10% fetal bovine serum (FBS; Gibco, USA) and 1% penicillin streptomycin (Gibco, USA) in a cell incubator at 37°C, 5% CO₂, and 95% humidity. Plasma cells were cultured to the logarithmic growth phase, then digested, and passaged.
A549 and H460 cells in the logarithmic growth phase were collected, resuspended, and then seeded in a 6-well plate. When cell confluence reached 80%, transfection was performed. Specifically, the transfection of A549 cells was divided into vector group, OE-circ_001042 group, control group, transforming growth factor β1 (TGF-β1) group, TGF-β1 + vector group, and TGF-β1 + circ_001042 group. The transfection of H460 cells was divided into vector group and OE-circ_001042 group. The foresaid vectors were transfected into the corresponding cells based on the transfection instructions of lipo2000 reagent, and after 48 h, transfected cells were collected.

BEAS-2B (human lung bronchial epithelial cells), A549, H1299, HCC827, and Calu-1 (NSCLC cells) were purchased from the National Collection of Authenticated Cell Cultures (Shanghai, China). Dulbecco’s modified Eagle medium (Thermo Fisher Scientific, Waltham, MA, USA) was used for culturing BEAS-2B cells, whereas Roswell Park Memorial Institute-1640 medium (Thermo Fisher Scientific) was used for culturing lung cancer cells. All media were supplemented with 1% penicillin–streptomycin and 10% fetal bovine serum (FBS). Cells were cultured in an incubator containing 5% CO₂ at 37 °C. All cell lines were cultured, maintained, and used in the range of 10 to 20 passages. The RS 2000 X-ray Biological Irradiator (Rad Source Technologies, Suwanee, GA, USA) was used to produce X-rays (225 kVp, 1.12 Gy/min). The Heavy Ion Medical Accelerator in Chiba (HIMAC) at the National Institute of Radiological Science was used to produce carbon ion beams (290 MeV/u, 1.22 Gy/min). The linear energy transfer (LET) of C290 at the entrance of the plateau was 13.3 keV/μm, whereas the LET in the spread-out Bragg peak was 80 keV/μm.

The following cell lines were purchased from the Cell Bank of Chinese Academy of Sciences (Shanghai, China): 293T cells, human lung epithelial cells (BEAS-2B), and human LUAD cell lines (A549, NCI-H1975, H1299, and HCC827). All cells were cultured in Roswell Park Memorial Institute-1640 medium (Gibco, NY, USA) supplemented with 10% fetal bovine serum (FBS; Gibco) and 1% penicillin/streptomycin (Invitrogen, CA, USA) in a humidified incubator (Thermo Scientific, CA, USA) at 37°C and 5% CO₂.

Six human lung cancer cell lines (A549, NCI-H358, NCI-H1650, NCI-H460, NCI-H1688, Calu-1), one human non-tumorigenic lung epithelial cell line (BEAS-2B), and HEK-293T cells were purchased from Cell Bank of Chinese Academy of Sciences (Shanghai, China). All the cell lines included in this study have been authenticated by STR profiling and tested for mycoplasma contamination. The cells were seeded and grown in Bronchial Epithelial Cell Growth Medium (BEGM, Lonza, Switzerland) containing 10% fetal bovine serum (FBS, Thermo Fisher Scientific, MA, USA) and 1% penicillin–streptomycin (Thermo Fisher Scientific). HEK-293T cells were cultured in Dulbecco’s modified eagle medium (DMEM, Thermo Fisher Scientific) supplemented with 10% FBS and 1% penicillin–streptomycin. The cells were cultured in the CO₂ incubator at 37 °C. For drug treatment, TGF-β1 (5 ng/mL, Sigma-Aldrich, CA, USA) and AG490 (25 μM, Sigma-Aldrich) were added to the culture medium to stimulate cancer cells.