Targeting Overexpressed IDO in Stromal Cells as a Potential Therapeutic Strategy in Multiple Myeloma.

ABSTRACT: Stromal cells are an essential component of the tumor microenvironment (TME) in multiple myeloma (MM). Indoleamine 2,3-dioxygenase 1 (IDO), an enzyme that metabolizes tryptophan (Trp) to kynurenine (Kyn), plays an immunosuppressive role in the TME. We previously reported that a high Kyn/Trp ratio was associated with poor prognosis in lenalidomide-treated refractory/relapsed MM patients and that IDO expression in stromal cells was upregulated by co-culture with MM cells. Here, we analyzed the mechanism through which MM cells upregulate IDO in stromal cells and aimed to identify compounds that inhibit IDO upregulation. Two MM cell lines, XG-7 and IM-9, upregulated IDO in stromal cells both directly and indirectly. These two MM cell lines also upregulated programmed cell death ligand 1 (PD-L1

SUBMITTER: Ebina T 

PROVIDER: S-EPMC12861097 | biostudies-literature | 2026 Feb

REPOSITORIES: biostudies-literature