CD133+ renal progenitor cells contribute to tumor angiogenesis.

In the present study, we tested the hypothesis that resident progenitor cells may contribute to tumor vascularization and growth. CD133+ cells were isolated from 30 human renal carcinomas and characterized as renal resident progenitor cells on the basis of the expression of renal embryonic and mesenchymal stem cell markers. CD133+ progenitors differentiated into endothelial and epithelial cells as the normal CD133+ counterpart present in renal tissue. In the presence of tumor-derived growth factors, these cells were committed to differentiate into endothelial cells able to form vessels in vivo in SCID mice. Undifferentiated CD133+ progenitors were unable to form tumors when transplanted alone in SCID mice. When co-transplanted with renal carcinoma cells, CD133+ progenitors significantly enhanced tumor development and growth. This effect was not attributable to the tumorigenic nature of CD133+ progenitor cells because the same results were obtained with CD133+ cells from normal kidney. CD133+ progenitors contributed to tumor vascularization as the majority of neoformed vessels present within the transplanted tumors were of human origin and derived from the co-transplanted CD133+ progenitors. In conclusion, these results indicate the presence of a renal progenitor cell population in renal carcinomas that may differentiate in endothelial cells and favor vascularization and tumor growth.

Multicenter study on the use of gemcitabine to prevent recurrence of multiple-recurring superficial bladder tumors following intravesical antiblastic agents and/or BCG: evaluation of tolerance.

OBJECTIVES: The treatment of choice for superficial bladder TCC is endoscopic resection, followed or not by intravesical immuno/chemotherapy. Some patients are not responders to common intravesical therapy and are more exposed to disease progression. In this case the suitable treatment is radical cystectomy. Because gemcitabine is effective against advanced bladder cancer, we have initiated a study to evaluate the efficacy of its intravesical use to prevent relapse and disease progression, and tolerance and safety of this drug in patients with multi-treated bladders. In this preliminary study, we cite only data on tolerance. MATERIALS AND METHODS: 64 patients were selected, and 61 were evaluable (age range 39-84 years), with multiple-recurrent bladder TCC. All patients were previously treated with intravesical chemotherapy and/or immunotherapy. The protocol provided for intravesical instillation of gemcitabine (2000 mg) once per week for 8 weeks. We collected data regarding problems noted by the patients (both local and systemic). RESULTS: 53 patients out of 61 (86.9%) completed the cycle. Side effects appeared in 14 patients, 8 of these had to suspend the treatment. Severe side effects were systemic in 4 patients (1 systemic edema, 1 malaise and dysgeusia, 1 hyperthermia and severe strangury, 1 elevated transaminases and asthenia), and local in 4 patients (1 severe urinary urgency, 1 hematuria, 1 urinary incontinence, and 1 case of pelvic pain). In 6 patients we observed pelvic pain, hematuria, strangury and UTI of medium magnitude that did not require treatment interruption. CONCLUSIONS: We believe that the severe side effects requiring treatment interruption are attributable primarily to increased sensitivity in patients with multi-treated bladders. In our experience, the side effects responsible for suspension occurred at the start of treatment in 7 cases out of 8. Our study demonstrates the safety of intravesical gemcitabine in patients with recurrent and multi-treated superficial TCC of the bladder.