Intercellular transfer of P-glycoprotein from the drug resistant human bladder cancer cell line BIU-87 does not require cell-to-cell contact.

PURPOSE: The efflux activity of transmembrane P-glycoprotein prevents various therapeutic drugs from reaching lethal concentrations in cancer cells, resulting in multidrug resistance. We investigated whether drug resistant bladder cancer cells could transfer functional P-glycoprotein to sensitive parental cells. MATERIALS AND METHODS: Drug sensitive BIU-87 bladder cancer cells were co-cultured for 48 hours with BIU-87/ADM, a doxorubicin resistant derivative of the same cell line, in a Transwell® system that prevented cell-to-cell contact. The presence of P-glycoprotein in recipient cell membranes was established using fluorescein isothiocyanate, laser scanning confocal microscopy and Western blot. P-glycoprotein mRNA levels were compared between cell types. Rhodamine 123 efflux assay was done to confirm that P-glycoprotein was biologically active. RESULTS: The amount of P-glycoprotein protein in BIU-87 cells co-cultured with BIU-87/ADM was significantly higher than in BIU-87 cells (0.44 vs 0.25) and BIU-87/H33342 cells (0.44 vs 0.26, each p <0.001), indicating P-glycoprotein transfer. P-glycoprotein mRNA expression was significantly higher in BIU-87/ADM cells than in co-cultured BIU-87 cells (1.28 vs 0.30), BIU-87/H33342 (0.28) and BIU-87 cells (0.25, each p <0.001), ruling out a genetic mechanism. After 30 minutes of efflux, rhodamine 123 fluorescence intensity was significantly lower in BIU-87/ADM cells (5.55 vs 51.45, p = 0.004) and co-cultured BIU-87 cells than in BIU-87 cells (14.22 vs 51.45, p <0.001), indicating that P-glycoprotein was functional. CONCLUSIONS: Bladder cancer cells can acquire functional P-glycoprotein through a nongenetic mechanism that does not require direct cell contact. This mechanism is consistent with a microparticle mediated process.

Intravesical hyaluronic acid and alkalinized lidocaine for the treatment of severe painful bladder syndrome/interstitial cystitis.

INTRODUCTION AND HYPOTHESIS: Intravesical instillation of hyaluronic acid (HA) may restore the integrity of glycosaminoglycan layer in patients with painful bladder syndrome/interstitial cystitis (PBS/IC), and the benefit may be improved with addition of alkalinized lidocaine (AL). METHODS: 48 women with severe PBS/IC who failed oral medications were enrolled and divided into one trial and two control groups. The trial group received intravesical 40 mg HA, 10 ml of 2 % lidocaine and 5 ml of 8.4 % sodium bicarbonate on a weekly basis for 8 weeks and then monthly for 4 months with a subsequent follow-up of 24 weeks, while the two control groups received 40 mg HA and mixture of 10 ml of 2 % lidocaine and 5 ml of 8.4%sodium bicarbonate respectively following the same procedure. Response to therapy was evaluated by Global Response Assessment, voids per day, Visual Analogue Scale for pain, frequency and urgency, O'leary-Sant Interstitial Cystitis Symptom Index and Problem Index, cystoscopy and bladder capacity. RESULTS: Overall 45 patients finished this study protocol. The HA + AL group and the AL group showed significant improvement at week 2 (P < 0.01), while the HA group began to show effect at week 4 (P < 0.01). There was no improvement in the AL group at week 24 and these patients quitted the study without follow up. Contrarily, the HA + AL and HA group kept on improving till the end of the study without significant difference between the two groups. CONCLUSIONS: Intravesical instillation of HA and AL may provide both immediate and sustained relief of symptoms in severe PBS/IC in this preliminary study.

The role of TSG-6 and uroplakin III in bladder pain syndrome/ interstitial cystitis in rats and humans.

OBJECTIVES: We investigated the relationship between the expression of tumor necrosis factor-inducible gene 6 (TSG-6) with inflammation and integrity of the bladder epithelium in the bladder tissues of patients with bladder pain syndrome/interstitial cystitis (BPS/IC) and the mechanism of action using a rat model of BPS/IC. MATERIALS AND METHODS: Expression of TSG-6 and uroplakin III was determined by immuno- histochemistry of bladder biopsy samples from control human subjects and patients with verified BPS/IC. Our rat model of BPS/IC was employed to measure the perfusion of bladders with hyaluronidase, and assessment of the effect of TSG-6 administration on disease progression. Treatment effects were assessed by measurement of metabolic characteristics, RT-PCR of TGR-6 and interleukin-6, bladder histomorphology, and immunohistochemistry of TGR-6 and uroplakin III. RESULTS: The bladders of patients with BPS/IC had lower expression of uroplakin III and higher expression of TSG-6 than controls. Rats treated with hyaluronidase for 1 week developed the typical signs and symptoms of BPS/IC, and rats treated with hyaluronidase for 4 weeks had more serious disease. Administration of TSG-6 reversed the effects of hyaluronidase and protected against disease progression. CONCLUSION: Our results indicate that TSG-6 plays an important role in maintaining the integrity of the bladder epithelial barrier.