Monitoring the response of urothelial precancerous lesions to Bacillus Calmette-Guerin at the proteome level in an in vivo rat model

Recent animal models of bladder cancer and their application in drug discovery: an update of the literature

INTRODUCTION

Bladder cancer presents a significant health problem worldwide, with environmental and genetic factors contributing to its incidence. Histologically, it can be classified as carcinoma in situ, non-muscle invasive and muscle-invasive carcinoma, each one with distinct genetic alterations impacting prognosis and response to therapy. While traditional transurethral resection is commonly performed in carcinoma in situ and non-muscle invasive carcinoma, it often fails to prevent recurrence or progression to more aggressive phenotypes, leading to the frequent need for additional treatment such as intravesical chemotherapy or immunotherapy. Despite the advances made in recent years, treatment options for bladder cancer are still lacking due to the complex nature of this disease. So, animal models may hold potential for addressing these limitations, because they not only allow the study of disease progression but also the evaluation of therapies and the investigation of drug repositioning.

AREAS COVERED

This review discusses the use of animal models over the past decade, highlighting key discoveries and discussing advantages and disadvantages for new drug discovery.

EXPERT OPINION

Over the past decade animal models have been employed to evaluate new mechanisms underlying the responses to standard therapies, aiming to optimize bladder cancer treatment. The authors propose that molecular engineering techniques and AI may hold promise for the future development of more precise and effective targeted therapies in bladder cancer.

The role of ALDH2 in tumorigenesis and tumor progression: Targeting ALDH2 as a potential cancer treatment

A major mitochondrial enzyme for protecting cells from acetaldehyde toxicity is aldehyde dehydrogenase 2 (ALDH2). The correlation between ALDH2 dysfunction and tumorigenesis/growth/metastasis has been widely reported. Either low or high ALDH2 expression contributes to tumor progression and varies among different tumor types. Furthermore, the ALDH2∗2 polymorphism (rs671) is the most common single nucleotide polymorphism (SNP) in Asia. Epidemiological studies associate ALDH2∗2 with tumorigenesis and progression. This study summarizes the essential functions and potential ALDH2 mechanisms in the occurrence, progression, and treatment of tumors in various types of cancer. Our study indicates that ALDH2 is a potential therapeutic target for cancer therapy.

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.

Histopathologic and molecular comparative analyses of intravesical Aurora kinase-A inhibitor Alisertib with bacillus Calmette-Guérin on precancerous lesions of bladder in a rat model

PURPOSE

Recent studies have shown that Aurora-A expression is associated with bladder cancer initiation and progression. In this study, the effects of intravesical Aurora-A inhibitor Alisertib (ALS) and bacillus Calmette-Guérin (BCG) were compared on bladder carcinogenesis.

METHODS

Two mg N-Methyl-N-nitrosourea was administered intravesically to forty of Wistar-albino rats every other week for 8 weeks. At week 10, rats were divided into four groups (10/group): No-treatment (vehicle), ALS-alone, BCG-alone, and ALS + BCG. The intravesical treatment of ALS, BCG, and ALS plus BCG was performed once a week for 6 weeks. At week 16, bladders were collected for immunohistopathological and Western blot analysis. The cell cycle regulators p53, p21, Aurora-A, phosphorylated Aurora-A (p-Aurora-A), and apoptotic marker cleavage of poly [ADP-ribose] polymerase (c-PARP) were determined by Western blot.

RESULTS

Histopathologically relatively healthy urothelium was observed in ALS + BCG group (87.5%) compared to the ALS-alone (50%) and the BCG-alone (50%) groups. The lowest expression of p21 and p53 was detected in the BCG-alone, while the highest level of expression was evident in no-treatment group. The ALS treatment alone caused a slight decrease in Aurora-A while there was a dramatic decrease in p-Aurora-A in comparison to no-treatment group. In overall combined treatment with ALS + BCG significantly increased c-PARP compared to all mono-treatments, and decreased all cell cycle parameters compared to no-treatment group.

CONCLUSIONS

Although intravesical ALS treatment has similar antiproliferative effects like BCG, ALS + BCG combined treatment led to a best histopathologic and apoptotic response. Consequently, BCG combined with Aurora-A inhibition may provide a new intravesical treatment modality in the prevention of bladder carcinogenesis.