The effect of short-chain fatty acids butyrate, propionate, and acetate on urothelial cell kinetics in vitro: potential therapy in augmentation cystoplasty.

The intestinal element of enterocystoplasty is affected by chronic inflammatory changes, which lead to excess mucus production, urinary tract infections, and stone formation. There is also an increased risk of malignancy. These inflammatory changes may be due to diversion colitis, which affects colonic segments excluded from the faecal stream and likewise may respond to intraluminal short-chain fatty acid (SCFA) therapy. The SCFAs have interesting antiproliferative, differentiating, and pro-apoptotic effects, which are protective against colorectal cancer and may influence the risk of malignancy in enterocystoplasty. Before intravesical therapy can be considered, the effect on normal urothelium must be investigated. Primary urothelial cells cultured from biopsy specimens and transformed urothelial (RT112 and MGH-U1) and intestinal cell lines (HT29 and CaCo-2) were incubated with SCFAs. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay was used to measure the residual viable biomass to assess cell proliferation. Proliferation of primary and transformed urothelial cells in culture was inhibited by all SCFAs in a similar time- and dose-dependent manner. The concentration of SCFA required to inhibit growth of primary cells by 50% (IC50) was 20 mM of butyrate, 120 mM of propionate, and 240 mM of acetate after incubation for 1 h. After 72 h the IC50 was 2 mM of butyrate, 4 mM of propionate, and 20 mM of acetate. Transformed urothelial and colon cancer cell lines demonstrated similar growth inhibition. Butyrate was the most potent inhibitor of cell proliferation, followed by propionate and then acetate. Growth inhibition is not an immediate cytotoxic effect, and urothelial cells show a degree of adaptation to butyrate and growth recovery after incubation with butyrate. In conclusion, butyrate- and propionate-induced growth inhibition is potentially clinically significant and may have therapeutically beneficial implications in vivo.

Intravesical meglumine gamma-linolenic acid in superficial bladder cancer: an efficacy study.

OBJECTIVES: Gamma-linolenic acid (GLA) is known to be cytotoxic to malignant cells. We assessed the efficacy of the novel intravesical formulation, meglumine gamma-linolenic acid (MeGLA), in a phase II trial, in patients with recurrent, superficial bladder cancer. PATIENTS AND METHODS: Thirty patients with recurrent, superficial transitional cell carcinoma (TCC) were recruited. The tumour pattern was recorded at flexible cystoscopy. Patients received a single intravesical instillation of 50ml of either 50mg (1mg/ml) (15 patients), or 125mg (2.5mg/ml) (15 patients) of MeGLA in water, retained for one hour. At subsequent cystoscopy, the tumour patterns were recorded, prior to undertaking routine cystodiathermy. Biopsies were obtained for histological assessment. Responses were divided into complete, partial or none. RESULTS: All 30 patients retained the drug for 1 hour without significant local or systemic side effects. There were 4 (13%) complete responses, 9 (30%) partial responses, and 17 (57%) non-responders. Histology showed no evidence of damage to surrounding urothelium. CONCLUSIONS: Our data confirms the safety and tolerability of MeGLA, which is consistent with findings from a previous phase I trial. A response rate of 43% also indicates that MeGLA has a significant cytotoxic effect against TCC and the results are similar to those obtained using standard, single-dose, intravesical regimens.

The effects of meglumine gamma linolenic acid (MeGLA) on an organ culture model of superficial bladder cancer.

The objective of this research was to assess the effects of the novel intravesical drug MeGLA in a physiologically representative model of superficial bladder cancer. Petri dishes were used to culture 5 mm square explants of rat bladder in minimal volumes of supplemented culture medium. Parental and resistant MGH-U1 urothelial cancer cells were transfected with a green fluorescent protein (GFP) vector. Transfectants were purified by flow cytometry. Cells were seeded onto the prepared organ cultures and imaging was performed using confocal microscopy. Confirmation of the tumour colonies was done using scanning electron microscopy. MeGLA was added at various concentrations to the colonies and its effects noted over several days. Results showed that colonies of GFP-MGH-U1 cells established themselves on the explants and could be identified by confocal microscopy. The colonies could then be followed over several days. The colonies were able to survive high concentrations of the drug of up to 1 mg/ml, 400 times the IC > 90% for monolayers and equivalent to doses in clinical use. We conclude that MeGLA is less effective in this system than on monolayer cell lines. However, it showed cytotoxic effects which were comparable to those seen with conventional agents in the same system.