Mitoxantrone

The σ₂ receptor ligand A011 was prepared as previously reported (Feng et al., 2019 (link)). KO143 was purchased from MedChemExpress (Monmouth Junction, NJ, United States). Cisplatin (DDP), adriamycin (ADR), paclitaxel, verapamil, mitoxantrone and rhodamine 123 (Rh123) were acquired from Solarbio (Beijing, China). Cell Counting Kit-8 (CCK-8) was bought from Dojindo Laboratories (Japan). Pgp-Glo™ Assay Systems were purchased from Promega (Madison, USA). Anti-P Glycoprotein antibody, ABCG2, GAPDH, Goat Anti-Rabbit IgG H&L Secondary Antibody (Alexa Fluor 488), Goat Anti-Rabbit IgG H&L Secondary Antibody and Goat Anti-Mouse IgG H&L Secondary Antibody were purchased from Abcam (Cambridge, United Kingdom). SlowFade^TM Gold antifade reagent was purchased from Thermo Fisher (MA, United States).

Mitoxantrone (> 97%), IPTG (Isopropyl β-D–Thiogalactopyranoside), and dialysis membranes (MWCO: 3500D) were bought from Solarbio (Beijing, China). Urea was obtained from J&K. (Beijing, China). Ni–NTA–Sefinose TM Column was sourced from Sangon (Shanghai, China). Ultracel-10 regenerated cellulose membrane was provided by Merck KGaA (Darmstadt, Germany). Other reagents were all purchased from Aladdin (Shanghai, China).
Murine embryonic fibroblast cells NIH3T3, murine colon adenocarcinoma cells CT26 and MC38 cells obtained from the American Type Culture Collection (ATCC, Rockville, MD) were cultured in RPMI 1640 and DMEM, respectively, supplemented with 10% fetal bovine serum (FBS, Gbico, Massachusetts, USA), 100 μg/mL streptomycin sulfate, and 100 Unit/mL penicillin G sodium. All cells were cultured in humidified incubator containing 5% CO₂ at 37 °C.
Male C57BL/6 mice and male BALB/c mice (6 weeks, 18–22 g), provided by Guangdong Medical Laboratory Animal Center (Guangdong, China), were raised with sterile water and food in standard conditions. All ethical regulations relevant to animal research were approved by the Institutional Animal Care and Use Committee of Southern Medical University.