Enhancement of PD-L1-attenuated CAR-T cell function through breast cancer-associated fibroblasts-derived IL-6 signaling via STAT3/AKT pathways

• Published in: Breast cancer research : BCR 2023-07, Vol.25 (1), p.86-86, Article 86
• Main Authors: Chuangchot, Nisa, Jamjuntra, Pranisa, Yangngam, Supaporn, Luangwattananun, Piriya, Thongchot, Suyanee, Junking, Mutita, Thuwajit, Peti, Yenchitsomanus, Pa-Thai, Thuwajit, Chanitra
• Format: Article
• Language: English
• Subjects: AKT protein; Apoptosis; B7-H1 Antigen - genetics; Breast cancer; Cancer-associated fibroblast; Cancer-Associated Fibroblasts; CAR-T cell; Cell culture; Cell therapy; Chemotherapy; Cytotoxicity; Development and progression; Doxorubicin; Drug resistance; Enzyme-linked immunosorbent assay; Extracellular signal-regulated kinase; FDA approval; Fibroblasts; Flow cytometry; Folate receptor-α; Folic acid; Growth factors; Humans; IL-6; Interleukin 6; Interleukin-6 - genetics; Kinases; Ligands; Liver cancer; Lymphocytes; Lymphocytes T; Metastasis; Microscopy; PD-L1; PD-L1 protein; Phosphorylation; Proteins; Proto-Oncogene Proteins c-akt; Receptors, Chimeric Antigen; Software; Stat3 protein; STAT3 Transcription Factor - genetics; T cells; T-Lymphocytes; Triple Negative Breast Neoplasms - genetics
• ISSN: 1465-542X; 1465-5411; 1465-542X
• DOI: 10.1186/s13058-023-01684-7

Carcinoma-associated fibroblasts (CAFs) play a critical role in cancer progression and immune cell modulation. In this study, it was aimed to evaluate the roles of CAFs-derived IL-6 in doxorubicin (Dox) resistance and PD-L1-mediated chimeric antigenic receptor (CAR)-T cell resistance in breast cancer (BCA). CAF conditioned-media (CM) were collected, and the IL-6 level was measured by ELISA. CAF-CM were treated in MDA-MB-231 and HCC70 TNBC cell lines and siIL-6 receptor (IL-6R) knocked down (KD) cells to determine the effect of CAF-derived IL-6 on Dox resistance by flow cytometry and on increased PD-L1 through STAT3, AKT and ERK1/2 pathways by Western blot analysis. After pre-treating with CM, the folate receptor alpha (FRα)-CAR T cell cytotoxicity was evaluated in 2D and 3D spheroid culture assays. The results showed a significant level of IL-6 in CAF-CM compared to that of normal fibroblasts (NFs). The CM with high IL-6 level significantly induced Dox resistance; and PD-L1 expression through STAT3 and AKT pathways in MDA-MB-231 and HCC70 cells. These induction effects were attenuated in siIL-6R KD cells. Moreover, the TNBC cell lines that were CM-treated with STAT3 and an AKT inhibitor had a reduced effect of IL-6 on PD-L1 expression. BCA cells with high IL-6 containing-CM treatment had resistance to cancer cell killing by FRα CAR-T cells compared to untreated cells. These results highlight CAF-derived IL-6 in the resistance of chemotherapy and T cell therapy. Using inhibitors of IL6-STAT3/AKT-PD-L1 axis may provide a potential benefit of Dox and CAR-T cell therapies in BCA patients.