Ab215038

The patient-derived tumor xenograft (PDX) models were generated by direct transplantation of colon cancer patient tumor samples into immunocompromised NOD-scid IL2R gamma null (NSG) mouse, then the tumors were transplant to fifth to sixth-week-old BALB/c (nu/nu) mice. When the subcutaneous tumors attained a volume of 100 mm³ (day 0), the mice bearing tumor were divided into two groups, the mice in the treatment group were injected intraperitoneally (ip) tunicamycin 1 mg/kg (20 μg/mouse), three times a week, while the mice in the control group were received PBS only. The experiment was terminated and the tumor was removed after 3 weeks. Tumors were extracted for volume and weight measurement, and then fixed, embedded, and sectioned. Tumor sections were subjected to IHC staining for GRP78 (1:100, cat. 3177, CST), p73 (1:100, cat. Ab215038, Abcam), and Bim (1: 200, cat. 2933, CST). Written informed consent was obtained from the colon cancer patient and tumor specimens was approved by the Institutional Review Board at Chengdu Medical college. All animal experiments in this study were approved by the Animal Policy and Welfare Committee of Chengdu Medical College and the Institutional Animal Care and Use Committee (IACUC) of Sichuan University, and the procedures were performed according to the guidelines established by the China Council on Animal Care.

Coimmunoprecipitation (CoIP) was performed using the Minute™ Total Protein Extraction Kit for Animal Cultured Cells/Tissues (Invent Biotechnologies, United States). Cells for CoIP were treated with DMSO or PEITC for 24h. SN-002 buffer was used to lyse the cells, and a BCA protein assay kit (Solarbio, China) was used to measure protein concentrations. We incubated lysates with antibodies overnight at 4°C before incubating them with protein A agarose for 2 hours. We washed beads three times with 1× PBS and boiled them with SDS-PAGE Sample Loading Buffer (5×, with DTT) (Leagene Biotecnology, China). For the analysis of protein interactions between immunoprecipitated samples, immunoblotting was performed. The anti-p53 (Proteintech, #10442-1-AP), anti-PAb240 (Merck Millipore, #OP29L), anti-PAb1620 (Merck Millipore, #OP33) and anti-p73 (abcam, #ab215038) were used.