Propidium iodide (PI) was purchased from BioLegend, USA. efficacy of local cancer chemotherapy, we hypothesized that the local delivery of chemotherapeutic plus autophagy-enhancing agents would enhance the promotive effects of ICD on the antitumor immune response. Here, we report that a low-dose chemotherapy/autophagy enhancing regimen (CAER) not only resulted in the increased death of B16F10 and 4T1 tumor cells, but also induced higher levels of autophagy inhibition of the mTOR pathway, thereby inhibiting tumor growth (24, 25). However, systemic rapamycin administration can also suppress the immune system by blocking mTOR on T cells, leading to reduced interleukin (IL-2) production and inhibition of T-cell proliferation, which impair antitumor immune responses (26, 27). These observations led us to speculate that local delivery of chemotherapeutic and autophagy-enhancing drugs (chemotherapy/autophagy-enhancing regimen, CAER) might enhance the efficacy of local cancer treatment. Here, we report that a low-dose local CAER could activate autophagy and enhance autophagy-associated death The local delivery of low-dose CAER drugs not only efficiently inhibit the growth of the treated malignant melanoma- and breast cancer-derived tumors, but also of the contralateral Cdh15 nontreated ones. Further analysis showed that the immune system was activated to target the cancer cells. This HA-100 dihydrochloride research provides a new therapeutic approach for the treatment of cancer the local delivery of CAER drugs with systemic antitumor T-cell responses and reduced side effects. Materials and Methods Reagents Rapamycin (Rap) (Sigma, USA) was dissolved in DMSO and then diluted with RPMI medium. Chemotherapeutic drugs paclitaxel (PTX) and adriamycin (ADM) were purchased from the First Affiliated Hospital of Jinan University (Guangzhou, China). PMA/Ionomycin (P/I) were purchased from Sigma, USA. The peptides for immunogenic B16F10 and 4T1 mutations were synthesized by Sangon Biotech (Shanghai, China) accordingly previous publication ( Figure S3A ). Propidium iodide (PI) was purchased from BioLegend, USA. LC3B antibody was from Cell Signaling, USA. Anti-CD3, anti-CD4, anti-CD8, and anti-FOXP3 antibodies were purchased from Abcam, Cambridge, UK. Antibodies used for flow cytometry assay were as follows: anti-CD16/32 mAb (BD Biosciences, USA), anti-CD3-PEcy5, anti-CD4-FITC, anti-CD8-FITC, anti-IFN–APC, anti-TNF–PE, and anti-FOXP3-PE (BioLegend, USA). Traditional (2D) and 3D Cell Culture and Cell Proliferation Assays Colony Formation Assay Cells were seeded in 12-well plates (300 cells/well) and cultured under normal culture conditions (2D). After five days of incubation, B16F10 and 4T1 cells were either vehicle-treated or treated with low-dose of single chemotherapy drugs (2.5 g/mL PTX or 0.05 g/mL ADM) for two days, or with combination of two HA-100 dihydrochloride drugs as following: the same low-dose of chemotherapeutic drugs for 12?h, followed by treatment with 0.014 g/mL rapamycin (15 nM) for another 36?h. The medium was changed every three to four days. After two weeks, cells were stained with 0.1% crystal violet in methanol for 15?min, and the number of colonies (containing 50 or more cells) was visualized and quantified by light microscopy (CKX31, OLYMPUS, Japan). Spheroid Formation and Autophagic Cell Death Staining Assay A total of 600 B16F10 and 4T1 cells/well were seeded in ultra-low attachment 96-well plates in RPMI 1640/DMEM to establish spheroid cultures (3D). After three days, the cells were treated with vehicle or chemotherapeutic drugs (5 g/mL PTX or 0.1 g/mL ADM) for 6C8 h followed by treatment with 0.023 g/mL rapamycin (25 nM) for another 16C24 h. Finally, the diameter of each spheroid was measured after one week. The HA-100 dihydrochloride spheroids were stained with PI to determine the level of autophagic cell death. Autophagy Assays Monodansylcadaverine (MDC) Staining for Autophagy The entire dynamic autophagic process (autophagic flux) can be measured using the autofluorescent?dye MDC, which specifically marks autophagic vacuoles. In brief, 2000 cells of B16F10 or 4T1 were seeded in a 96-well plate in RPMI 1640/DMEM culture medium and incubated for two days at 37C. Then, the cells were treated with vehicle or a low dose of chemotherapeutic drugs (5 g/mL PTX or 0.1 g/mL ADM) for 6C8 h, followed by treatment with rapamycin (25 nM) for another 16C24 h. The cells were then stained with MDC (Solarbio, USA) and observed using fluorescence microscopy. LC3 Immunofluorescence and WB Assay To measure the level of autophagy, cells were treated as described in section 2.3.1. The cells were then fixed in cold absolute methanol and blocked with 1% BSA in PBST buffer (PBS with 0.1% Tween 20) for 1?h and incubated with the primary antibody against LC3B overnight at 4C. The cells were subsequently incubated with a fluorochrome-conjugated secondary antibody diluted in blocking buffer for 1?h at room temperature in the HA-100 dihydrochloride dark. Finally, the stained samples were mounted.
