A simple method to induce hypoxia-induced vascular endothelial growth factor-A (VEGF-A) expression in T24 human bladder cancer cells.

Angiogenesis is an essential process for the establishment, development, and dissemination of several malignant tumors including bladder cancer. The hypoxic condition promotes the stabilization of hypoxia-inducible factor 1 alpha (HIF-1α), which translocates to the nucleus to mediate angiogenic factors including the vascular endothelial growth factor A (VEGF-A). AnaeroGen system was developed for microbiology area to create a low oxygen tension required to the growth of anaerobic bacteria. Here, we hypothesized the use of AnaeroGen system to induce hypoxia in T24 human bladder carcinoma cells, in order to promote the overexpression of VEGF-A. T24 cells were cultured in six-well plates containing McCoy medium. Exposures of T24 cells to hypoxia for 1, 8, 24, and 48 h were performed using the Oxoid AnaeroGen system, while T24 cells under normoxia were used as control. The expression of VEGF-A and HIF-1α was analyzed by real-time PCR. ELISA for HIF-1α was carried out. The VEGF-A expression increased significantly by Oxoid AnaeroGen-induced hypoxia in a time-depending manner, reaching the peak in 48 h of hypoxia. Although HIF-1α mRNA was not changed, HIF-1α protein was increased in the presence of hypoxia, reaching a peak at 8 h. These results demonstrated that the Oxoid AnaeroGen system is a simple method to expose T24 cells to hypoxia and efficiently to upregulate VEGF expression in T24 cells.

Renal Subcapsular Space of Balb/c Nude Mice as a Route for Evaluating Subpopulations of Human Bladder Carcinoma Cells.

BACKGROUND/AIM: Subpopulations of bladder cancer (BC) cells have been found in tumors, with different abilities for malignancy and chemotherapy resistance. The BC cell line T24 has frequently been used to evaluate this phenomenon. Since technical limits exist in orthotopic procedures, we evaluated the renal subcapsular space as an alternative route for analyzing subpopulations of T24 BC cells in vivo. MATERIALS AND METHODS: Balb/c nude mice underwent renal subcapsular inoculation with T24 cells, suspended in two different volumes of PBS. Four weeks post-inoculation, histology and immunohistochemistry were carried out. RESULTS: In all the animals inoculated with a 10 µl volume of suspended cells, a pseudo-bladder structure in the renal subcapsular space was observed, with differential expression of mesenchymal and epithelial markers. T24 cells infiltrating the renal parenchyma towards the medulla and vessels were also observed. The volume used for inoculation was an important factor for the success of this technique. CONCLUSION: Renal subcapsular inoculation is an effective route for analyzing subpopulations and differentiation of T24 cells.

1-Methyl-D-tryptophan potentiates TGF-ß-induced epithelial-mesenchymal transition in T24 human bladder cancer cells.

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-ß1 is believed to contribute to carcinoma development by modulating immunossupressive molecules, including IDO. In addition, TGF-ß1 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-ß1 in T24 human bladder carcinoma cells. When T24 cells were incubated with the IDO inhibitor (MT, 1-methyl-D-tryptophan), with TGF-ß1, and with MT+TGF-ß1, 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-ß1. 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-ß1 and MT is associated with EMT in T24 human bladder carcinoma cells. MT has potentiating effect in TGF-ß1-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.