Fig 2: IDO1 affects EMT through IL6/STAT3/PD-L1 in T24 and UMUC3 cells.(A) Expression of IL6 in T24 and UMUC3 cells after IDO1 knockdown detected by ELISA assays. (B) STAT3, P-STAT3, and PD-L1 were evaluated by Western blot analysis in T24 and UMUC3 cells after IDO1 knockdown. (C and D) T24 and UMUC3 cells after IDO1 knockdown were pretreated with 100 ng/ml of IL-6 for 48 hours. The protein levels of STAT3, P-STAT3, PD-L1, and EMT-associated markers were determined by Western blot analysis.

Fig 3: IDO immune microenvironment hypothesis. (Chemo)radiotherapy and CDA treatments activate STING to incite antitumour immunity but also boost immune regulation to enhance therapy resistance. Multiple STING-responsive pathways involving chronic inflammation and tumour progression and associated with immune checkpoints (PD-1/L, CTLA-4, IDO) result in therapy resistance. Blocking these pathways modulate the TME in favour of antitumour immunity. Immune, inflammatory and metabolic biomarkers in blood reflect changes in the TME caused by treatments and therapy resistance. Abbreviations: CDA, cyclic diadenyl monophosphate; PD-1, programmed cell death protein 1; PD-L1, programmed death ligand 1; CTLA-4, cytotoxic T-lymphocyte-associated antigen 4; IDO, indoleamine 2,3-dioxygenase; IFN-1, interferon-1; NFkB, nuclear factor kappa-light-chain-enhancer of activated B cells

Fig 4: IDO activity mediated ASC modulation on macrophages. (A) The mRNA level of immunoregulatory factors in ASCs and ASCs stimulated with LPS. (B) The protein level of IDO-1 was detected in ASCs and ASCs stimulated with LPS. (C) Schematic diagram of inhibition of IDO-1 activity in ASCs treated with 1-MT in the coculture system. (D, E) The mRNA expression and protein levels of M1 and M2 markers in 1-MT-pretreated ASCs cocultured with macrophages, and ASCs cocultured with macrophages. (F) ELISA analysis of the release of the inflammatory cytokines TNF-a and IL-1ß.

Fig 5: AG490 blocks the IL6/STAT3/PD-L1 signaling pathway and is more pronounced after knockdown of IDO1. (A) T24 and UMUC3 cells after IDO1 knockdown were treated with STAT3 specific inhibitor AG490. The protein levels of STAT3, P-STAT3, and PD-L1 were measured by Western blot analysis. (B) EMT-associated markers were measured after treatment with AG490 by Western blot analysis.