Inhibition of mouse bladder tumor proliferation by alpha difluoromethylornithine and interferon in vitro and in vivo

New agents in intravesical chemotherapy of superficial bladder cancer

Although intravesical chemotherapy has been used in the management of superficial bladder cancer for some decades, until recently there has been little or no progress in the search for new agents. However, in the past few years there have been developments of investigational drugs that may play a future role in this indication. This review highlights the mode of action, indications, dose and administration, efficacy, safety and significance of new chemotherapeutic agents such as intravesical valrubicin, gemcitabine, suramin, gamma-linolenic acid, eflornithine (DFMO), tipifarnib (R115777), fenritinide and celecoxib. Although the initial results achieved with these agents in clinical development seem encouraging, long-term data on the prevention of recurrence, disease progression and survival have yet to be obtained.

Effects of diethyl spermine analogues in human bladder cancer cell lines in culture

The biochemical and antiproliferative effects of two recently developed N-alkylated analogues of naturally-occurring polyamines, N1,N14-diethylhomospermine (DEHSPM) and N1,N11-diethylnorspermine (DENSPM), were investigated in two human transitional cell carcinoma (TCC) lines, T24 and J82. Parallel studies with the ornithine decarboxylase enzyme inhibitor alpha-difluoromethylornithine (DFMO) were included for comparison. DENSPM displayed greater antiproliferative activity than DEHSPM in both TCC cell lines. Both analogues were strikingly more potent than DFMO. DEHSPM and DENSPM suppressed the activity of the major biosynthetic enzymes, ornithine decarboxylase and S-adenosylmethionine decarboxylase. However, differences in the resulting polyamine depletion suggest that the substantial antiproliferative activity of these analogues may result from mechanisms other than polyamine depletion. The greater polyamine depletion seen with DENSPM is thought to result from its striking induction of spermidine/spermine N1-acetyltransferase. DENSPM is an attractive agent for further preclinical and clinical development, possibly as a chemopreventive agent, in TCC of the bladder.

Immunotherapy of murine transitional cell carcinoma of the bladder using alpha and gamma interferon in combination with other forms of immunotherapy

BCG immunotherapy is very effective in the treatment of superficial transitional cell carcinoma of the bladder, but its significant toxicity may limit its use in some patients. In an effort to find less toxic and potentially more effective treatments we investigated the possible immunotherapeutic potential of combinations of Alpha Interferon (1000 IU) and Gamma Interferon (500 IU) with bacillus Calmette Guerin (BCG) (10(7) cfu), Interleukin-2 (4000 IU), and Keyhole Limpet Hemocyanin (50 micrograms.) in the MBT2 murine bladder cancer model. Significant reductions (p less than 0.05) in tumor incidence relative to the saline control, 83%, Day 35) was observed in groups receiving alpha interferon (42%), Keyhole limpet hemocyanin (42%), interleukin-2 (25%), alpha interferon + Keyhole limpet hemocyanin (17%), alpha interferon + interleukin-2 (33%), gamma interferon + BCG (42%), and gamma interferon + interleukin-2 (17%). All treatment groups with the exception of the group receiving gamma interferon had significantly reduced tumor volume (p less than 0.05) relative to the saline control. Combination treatment groups were significantly more effective than single agent treatments (p = 0.0057). The exhibited anti-tumor effect of these immunotherapeutic agents alone and in combination suggest that they may prove to be effective forms of immunotherapy for transitional cell carcinoma of the bladder.

Experimental intravesical therapy for superficial transitional cell carcinoma in a rat bladder tumor model

A rodent bladder cancer model that is induced by intravesical instillation of N-methyl-N-nitrosourea (MNU) was characterized. Cohorts of four to five week old female Fisher 344 rats received four biweekly 1.5 mg. doses of intravesical MNU and were sacrificed at various intervals. By week 13 all animals had flat atypia and/or papillary transitional cell tumors, and 67% of the lesions were moderately (grade II) or poorly differentiated (grade III). By week 20, 83% had gross muscle invasive tumors that eventually killed the host. A cohort of 40 MNU treated animals was subsequently treated commencing at week 17 after initiation of MNU with one of three intravesical six week regimens: 1) saline; 2) BCG (Tice strain); or 3) recombinant human tumor necrosis factor (RTNF) plus adriamycin. There was no difference in animal survival or tumor growth in any group of animals commencing therapy at week 17. A second cohort of 107 animals commenced therapy at 13 weeks after initiation of MNU with one of five intravesical six week regimens: 1) intravesical BCG (Tice strain); 2) adriamycin; 3) recombinant human tumor necrosis factor (RTNF); 4) RTNF plus adriamycin; or 5) BCG plus adriamycin. BCG, RTNF or adriamycin alone had no effect on tumor growth; however, BCG plus adriamycin and RTNF plus adriamycin commencing at week 13 significantly inhibited tumor growth and progression. In conclusion, this autochthonous intravesical rodent transitional cell carcinoma model appears useful for the following reasons: 1) it closely resembles human transitional cell carcinoma histologically and biologically in that all animals develop neoplastic changes in-situ that progress to muscle invasion and kill the host; 2) as with human bladder cancer these tumors do not respond to intravesical therapy if treated when tumor burden is large; however, tumor growth is inhibited when treated early; and 3) this model appears appropriate for screening and developing new intravesical treatments for superficial bladder cancer.