Urothelial carcinogen resistance driven by stronger Toll-like receptor 2 (TLR2) and Uroplakin III (UP III) defense mechanisms: a new model

Castration immunoregulates toll-like receptor-4 in male bladder cancer

PURPOSE

Among diverse Pattern Recognition Receptors (PRRs), Toll-like receptor-4 (TLR-4) is a key urothelial trigger for innate immune response impacting urothelial bladder carcinoma (BC). Androgen activation promotes immunotolerance, playing an immunoregulatory role by unknown mechanisms. We explored the castration impact on urothelial TLR-4 modulation in carcinogenesis and immunotherapeutic scenario.

METHODS

Intact (SHAM) versus castrated male Fisher-344 rats were evaluated in 2 scenarios: (A) Carcinogenesis: After randomization to SHAM (n = 5) and Castration (n = 5), carcinogenesis was induced by four intravesical doses of 1.5 mg/kg n-methyl-n-nitrosourea (MNU) every 15 days. (B) Treatment: After ultrasonographic confirmed MNU-induced papillary BC on week 8, rats were randomized to SHAM (n = 5) and Castration (n = 5) and offered 6 weekly intravesical treatment of 10⁶ CFU of bacillus Calmette Guerin (BCG) in 0.2 ml saline. After 15 weeks the urinary bladders underwent histopathology. Urothelial cell proliferation was measured by Ki-67 immunohistochemistry (IHC), and TLR-4 expression was quantified by IHC and WB.

RESULTS

Castration induced higher TLR-4 urothelial expression (p = 0.007) and anticarcinogenic effect with fewer urothelial tumors (60 vs. 80%) and lower urothelial cell proliferation compared to intact animals (p = 0.008). In the intravesical BCG treatment setting, castration has potentialized the BCG activation of TLR-4 (p = 0.007) with no residual in situ carcinoma compared to intact animals, suggesting the potential to amplify the BCG immune response.

CONCLUSION

To our knowledge, this is the first description of TLR-4 urothelial expression hormonal modulation. The described castration-mediated immunomodulation will help to improve the knowledge of urothelial cancer gender diversities and PRRs modulations with treatment implications.

Carcinogenesis and Bacillus Calmette-Guérin (BCG) Intravesical Treatment of Non-Muscle-Invasive Bladder Cancer under Tryptophan and Thymine Supplementation

PURPOSE

Evaluate tryptophan and thymine (TT) impact on carcinogenesis and intravesical BCG bladder cancer treatment.

METHODS

After identification of TT in vitro inhibitory effect in multiple cancer cell cultures, bladder cancer animal model was induced by MNU intravesical instillations and randomized into four groups: Control (n = 9), BCG (n = 9), TT (n = 7), and BCG + TT (n = 8). BCG groups received intravesical 106 CFU BCG in 0.2 ml saline for 6 consecutive weeks and TT groups received 1 g/kg (1:1) of TT via daily gavage. After 15 wk of protocol, animals were euthanized and the urinary bladders submitted to histopathology, immunohistochemistry, and Western blotting.

RESULTS

Urothelial cancer was identified in 100%, 85.7%, 44.5%, and 37.5% of Control, TT, BCG, and BCG + TT groups, respectively. Cell proliferation marked by nuclear Ki-67 was higher in the Control compared to animals in the other groups (P = 0.03). BCG, TT, and BCG + TT groups showed proliferative cell decline and TLR4/5 labeling increase in the urothelium. BCG decreased the urothelial VEGF labeling, even in TT association.

CONCLUSION

TT inhibit urothelial carcinogenesis and potentiate the intravesical BCG in the treatment of bladder cancer by reducing cell proliferation and activating TLRs.

Boosting bladder cancer treatment by intravesical nitazoxanide and bacillus calmette-guérin association

PURPOSE

Nitazoxanide (NTZ) has shown a promising antitumoral effect, the current study compared the anti-neoplastic effects of intravesical NTZ and BCG plus NTZ in NMIBC animal model.

METHODS

30 rats, Fisher 344 were instilled with 4 intravesical doses of 1.5 mg/kg of N-methyl-N-nitrosourea (MNU) every 15 days for BC induction. The animals were divided into 3 groups (Group BCG 10⁶ UFC - 1 mg of BCG; Group NTZ - 300 mg/kg of NTZ; Group NTZ + BCG - simultaneous treatment of BCG and NTZ) and received weekly intravesical treatment for 6 consecutive weeks. Animals were submitted to ultrasound imaging and euthanasia, their bladders were collected and histopathological, immunohistochemical tests (ki67 e c-Myc) and Western Blotting (PI3K, mTOR, and p-4E-BP) were performed.

RESULTS

Histopathological tests showed 66.67%, 62.5% and 37.5% incidence of BC in animals treated with BCG, NTZ, and NTZ + BCG, respectively. Nuclear positivity for ki-67 in BC animals were 12.4% (IC 10.1-14.6%), 13.2% (IC 10.5-15.9%) and 8.8% (IC 6.0-11.6%) in BCG, NTZ and NTZ + BCG group, respectively (p = 0.063). Between animals with carcinoma, c-Myc strong positive was 40.10% in NTZ, 32.2% in BCG and 19.90% in the NTZ + BCG group (p < 0.001). Blotting has shown mTOR (p = 0.0473) and PI3K inhibition (p = 0.0349) in the presence of BCG, added to 4-EBP inhibition in the presence of NTZ (p = 0.0004).

CONCLUSIONS

Results show the possible synergy between the gold standard BC treatment BCG and NTZ, in which multiple targets inhibition such as c-Myc and downstream mTOR, p-4E-BP and PI3K might play a role.

Implantable orthotopic bladder cancer model in Wistar rats: A pilot and feasibility study

Purpose: The implantable bladder cancer (BC) models allow the researchers to perform rapid and useful experiments for BC. We investigated the implantation success of BC cells obtained from Wistar rats (grown in vitro), into bladders of syngeneic Wistar rats, which are commonly used in the laboratories.

Methods: The Nara Bladder Tumor No.2 (NBT-II) BC cells induced with 4-hydroxybutylnitrosamine were grown with passages in Kocaeli University Center for Stem-Cell and Gene-Therapies. After urothelial denudation, 2x106 NBT-II cells were then implanted into bladders of 24 female Wistar rats (aged 7-8 weeks). The rats were randomly divided into four experimental groups; three instillation groups (8 per group) and one sham-operated control group consisting of 6 rats. First, second and third instillation groups were sacrificed at days 7, 14, and 21, respectively, and, bladders were histopathologically evaluated for BC according to WHO / International Society of Urological Pathology.

Results: All tumors were pT1 (including 1 rat that prematurely died at 5th day), except one rat that died prematurely at 8th day had pT2 tumor. Implantation rates were 28.58% (2/7) in the first group, and 42.85% (3/7) in the second, for a cumulative rate of 35.71% (5/14) in these two-groups (until 14th day). Interestingly, there was no tumor in the third group, but there was an inflammatory granulation tissue.

Conclusion: Seeding NBT-II cells into bladders of Wistar rats was described, successfully tested and demonstrated in this study. This implantable BC model of Wistar rats may be improved to increase the success rate of BC cell implantation in new studies with higher number of animals.