1-Methyl-D-tryptophan potentiates TGF-?-induced epithelial-mesenchymal transition in T24 human bladder cancer cells.
Ontology highlight
ABSTRACT: Immune escape and metastasis are the hallmarks of several types of cancer including bladder cancer. One of the mechanisms involved in these processes has been linked to indoleamine 2,3-dioxygenase (IDO). Although IDO is classically recognized for its immunomodulatory property, it has presented nonimmunological effects in some tumors. TGF-?1 is believed to contribute to carcinoma development by modulating immunossupressive molecules, including IDO. In addition, TGF-?1 induces the epithelial-mesenchymal transition (EMT), which is a critical step in the tumor invasiveness and metastasis. We investigated the role of MT and IDO modulation in the induction of EMT by TGF-?1 in T24 human bladder carcinoma cells. When T24 cells were incubated with the IDO inhibitor (MT, 1-methyl-D-tryptophan), with TGF-?1, and with MT+TGF-?1, a significant decrease of IDO expression and activity was observed. In addition, downregulation of e-cadherin and upregulation of n-cadherin and EMT transcription factors were induced by the treatments, confirming the induction of EMT. siRNA-mediated knockdown of IDO decreased e-cadherin expression, but had no effect on EMT transcription factors. In the scratch-wound assay, the heightened migration process was intensified when the cells were incubated with MT+TGF-?1. These effects were associated with a robust inhibition of Akt activation. After inoculation of T24 cells under the kidney capsule of Balb/c nude, the cells were positive for IDO in the center of the cell infiltrate, being negative in the periphery, where EMT is high. In conclusion, inhibition of IDO by TGF-?1 and MT is associated with EMT in T24 human bladder carcinoma cells. MT has potentiating effect in TGF-?1-induced EMT, independently of IDO. This nonimmunological effect of MT should be considered if IDO is the target to avoid immune escape in bladder cancer.
SUBMITTER: Brito RB
PROVIDER: S-EPMC4534444 | biostudies-literature | 2015
REPOSITORIES: biostudies-literature
ACCESS DATA