Prevention of bladder tumor formation in mice by a novel bone marrow-derived factor, reptimed

Background: Reptimed is a novel, species-conserved bone marrow-derived mole cule which possesses anti-neoplastic activity. Previously, we established a n orthotopic murine bladder tumor (MBT-2) model and reported accurate docum entation of the presence and the extent of intravesical involvement of blad der tumor implants using magnetic resonance imaging (MRI) (1). Herein, we i nvestigated the activity of exogenously administered Reptimed in the MBT-2 model. Materials and Methods: Intravesicular and intraperitoneal administra tion of Reptimed concurrently with and following transurethral tumor cell i mplantation was performed and MBT-2 rumor response was assessed at several time points post tumor implant. Results: Serial MRI scans of Reptimed-treat ed mice at days 14 to 33 post tumor transplant revealed significant inhibit ion of bladder tumor growth with no significant tumor growth observed by MR I on day, 33 post-implant. The corresponding histological examination of th e whole mount bladder sections revealed similar inhibitory effects of Repti med with respect to the topography and depth of intravesical tumor involvem ent. In contrast, control, untreated bladders revealed extensive exophytic tumors with deeply invasive transitional cell carcinoma. Conclusions: These studies demonstrate the anti-tumor effect of Reptimed and highlight its im portance as a potential therapy for cancer.