Doxorubicin hydrochloride

Both human lung cancer cell lines (NCI-H23, and NCI-H2126) and HEK-293 cell line were procured from CAS-China and Microbix Biosystems Inc. respectively (Beijing, China). HEK-293 contains adenovirus (Adv) E1A-region for the replication of CRAd.
Cisplatin-resistant sublines, H23/CPR and H2126/CPR, were developed in our lab as described previously [24 (link)]. Afterward, all cancer cells were maintained in DMEM with 10% FBS and 2% of penicillin-streptomycin (HyCloneTM, Thermo Fisher Scientific, Waltham, MA USA USA). Doxorubicin (hydrochloride), cisplatin, elacridar, palbociclib, novobiocin, and probenecid were purchased from MedChemExpress (Shanghai, China) while puromycin was from Sigma-Aldrich. CRAd (incorporated with survivin promoter to regulate E1A region of Adv) was developed in our laboratory as described previously [35 (link)]. Ad-Luc expressing the firefly luciferase gene was used as a control.

The MCF7 and doxorubicin-resistant MCF7 (MCF7-DR) cell lines originally obtained from the Cell Bank of the Type Culture Collection of the Chinese Academy of Sciences Committee (Shanghai, China), were kindly provided by the key laboratory of breast cancer in Shanghai, Fudan University. All cells were cultured in DMEM medium (KEL Biotech, China), supplemented with 2 mM L-glutamine (Gibco, United States), 10% fetal bovine serum (KEL Biotech, China), 0.1 M sodium pyruvate (Gibco, United States), 50 units/mL penicillin and 50 μg/mL streptomycin (Sangon Biotech, China). The MCF7 and MCF7-DR cells were grown in 10-cm culture dishes at 37°C in a humidified 5% CO₂ atmosphere, and the medium was renewed every 2–3 days. Whereas parental MCF7 cells were grown in a drug-free medium, resistant-derived cells were maintained in doxorubicin hydrochloride (MedChem Express, United States) at a concentration of 1 μM. doxorubicin hydrochloride was stored at a concentration of 2 mM (2,000×) in DMSO (Sigma-Aldrich, United States) at −20°C.
Before any further experiments, the MCF7-DR cells were maintained in doxorubicin free medium for 3 days. Parental MCF7 cells were cultured in parallel with the MCF7-DR cells for comparison.

A CCK8 kit, doxorubicin hydrochloride, and the (6-maleimidocaproyl) hydrazone of DOX (DOXO-EMCH) were purchased from Med Chem Express LLC Co., Ltd. (Shanghai, China). DMEM/high glucose medium and trypsin were procured from GE Healthcare Life Sciences, while female BALB/c nude mice (8 weeks old) were obtained from Vital River Laboratory Animal Technology Co., Ltd. (Beijing, China). All other chemicals utilized in this study were purchased from J&K Scientific Ltd.

(−)‐epigallocatechin‐3‐O‐gallate (EGCG), dimethylformamide (DMF), dichloromethane (DCM), and methanol (CH₃OH) were purchased from Energy Chemical (Shanghai, China). 2,2‐Diphenyl‐1‐picrylhydrazyl (DPPH) and 2,2,3,3,4,4,5,5,6,6,7,7‐dodecafluoro‐1,8‐octanediol (12F) were purchased from Macklin Biochemical Co., Ltd. (Shanghai, China). Sorafenib, gemcitabine, and doxorubicin hydrochloride were purchased from MedChemExpress (New Jersey, USA). Oxalyl chloride solution was purchased from Aladdin Bio‐Chem Technology Co., Ltd. (Shanghai, China). FAM‐, Cy3‐, and Cy5‐labeled siRNA and siNC (sense strand, 5′‐UUC UCC GAA CGU GUC ACG UTT‐3′), siPD‐L1 (sense strand, 5′‐ AGG AUG GUU CUU AGA CUU UTT‐3′) were purchased from GenePharma Co., Ltd. (Shanghai, China). RNase enzyme and DAPI were purchased from Beyotime Biotechnology (Shanghai, China). Mouse TNF‐α and IFN‐γ ELISA kit were purchased from Wuhan Boster Biological Technology Co. Ltd. All other reagents were obtained from Beyotime Biotechnology Co., Ltd. (Shanghai, China) unless otherwise stated.

CME was obtained from UNIAL Co., Ltd. (Tokyo, Japan). Chrysanthemum morifolium was extracted with hot water, then drying it into a powder. This extract is a standardized product including chlorogenic acid (420 mg/100 g), delphinidin (690 mg/100 g), luteolin (32 mg/100 g), and total polyphenol (4.75 g/100 g) derived from Chrysanthemum morifolium Ramat. CME is available on UNIAL’s website (http://www.unial.info/materials/beauty.html (accessed on 28. January 2022). Doxorubicin hydrochloride was purchased from MedChemExpress (Monmouth Junction, NJ, USA) and stored at −20 °C until use.