Bladder cancer immunomodulatory effects of intravesical Nitazoxanide, Rapamycin, Thalidomide and Bacillus Calmette-Guérin (BCG).

PURPOSE: To understand the effect of Nitazoxanide (NTZ), Rapamycin, Thalidomide, alone and in combination with BCG on bladder cancer (BC) histopathology and programmed death-ligand 1 (PD-L1) and anti-cytotoxic T lymphocyte antigen 4 (CTLA4) expression. METHODS: Female Fisher-344 rats underwent intravesical N-methyl-N-nitrosourea (MNU) followed by weekly intravesical treatment with saline (controls, n = 10), BCG (n = 10), NTZ (n = 8), BCG plus NTZ (n = 8), Rapamycin (n = 10) BCG plus Rapamycin (n = 10), Thalidomide (n = 10), and BCG plus Thalidomide (n = 10), and euthanized after 8 weeks and their bladders were investigated for BC and PD-L1 and CTLA4 expression. RESULTS: Rapamicyn alone and in combination with BCG had the lowest number of bladder neoplasias in the histopathology exam (1/10). Neoplastic lesions were found in 4/10 BCG recipients, 5/10 Thalidomide recipients, 4/10 Thalidomide plus BCG recipients, 5/8 NTZ and 3/8 NTZ plus BCG recipients. Adding NTZ to BCG increased the expression of PD-L1 and adding Rapamycin or Thalidomide decreased PD-L1 and CTLA4 expression compared to BCG alone. Rapamycin alone significantly increased CTLA4 and slightly increased PD-L1 expression but its combination with BCG significantly decreased both markers. Thalidomide had a similar effect; however, it was only slightly different from the control and BCG alone groups. CONCLUSION: Intravesical BCG combination treatment seems to effectively prevent BC development in an immunecompetent clinically relevant animal model, introducing Thalidomide, Nitazoxanide, and specially Rapamycin as candidates in the intravesical immunotherapy advancement. Our study contributes in understanding the mechanism of cancer immunotherapy.

Autochthonous male urothelial carcinoma immune competent model: from induction to BCG transurethral treatment.

OBJECTIVE: To describe a new animal model of autochthonous urothelial cancer (UC) accessible by transurethral catheter in males, from induction to treatment. Seven-week-old male Fischer 344 rats were used. The first 10 animals were used to overcome and standardize the technical challenges of safe transurethral catheterization of male rats. The remaining 14 animals underwent intravesical N-Methyl-Nitrosourea (MNU) instillation for UC induction, of which six were randomized to undergo intravesical BCG treatment. The stretched male rat urethra travels 35 mm in a tortuous "S" shaped trajectory with a 180° angle behind the pubic bone, safely traversed by a 20G 36" 0.8 mm epidural catheter in a stretched, straightened urethra inserted after anterior dilation of the penile urethra with a 24G IV catheter. Histopathologic analysis of the urinary bladder demonstrated Stage pT1, pTa, and pTis lesions in the 8 controls, all with increased cell proliferation by Ki-67 expression and no pT1 or pTis in the animals 6 treated with BCG. This pioneering study describes an autochthonous, effective, and accessible transurethral animal model of immune-competent UC in males, and may help with understanding of the biology, immunology, and treatment of UC, which predominates in males.