Chemoprevention of bladder cancer

Exploring the role of natural bioactive molecules in genitourinary cancers: how far has research progressed?

The primary approaches to treat cancerous diseases include drug treatment, surgical procedures, biotherapy, and radiation therapy. Chemotherapy has been the primary treatment for cancer for a long time, but its main drawback is that it kills cancerous cells along with healthy ones, leading to deadly adverse health effects. However, genitourinary cancer has become a concern in recent years as it is more common in middle-aged people. So, researchers are trying to find possible therapeutic options from natural small molecules due to the many drawbacks associated with chemotherapy and other radiation-based therapies. Plenty of research was conducted regarding genitourinary cancer to determine the promising role of natural small molecules. So, this review focused on natural small molecules along with their potential therapeutic targets in the case of genitourinary cancers such as prostate cancer, renal cancer, bladder cancer, testicular cancer, and so on. Also, this review states some ongoing or completed clinical evidence in this regard.

Treatment of muscle-invasive and advanced bladder cancer in 2020

Bladder cancer accounts for nearly 170,000 deaths worldwide annually. For over 4 decades, the systemic management of muscle-invasive and advanced bladder cancer has primarily consisted of platinum-based chemotherapy. Over the past 10 years, innovations in sequencing technologies have led to rapid genomic characterization of bladder cancer, deepening our understanding of bladder cancer pathogenesis and exposing potential therapeutic vulnerabilities. On the basis of its high mutational burden, immune checkpoint inhibitors were investigated in advanced bladder cancer, revealing durable responses in a subset of patients. These agents are now approved for several indications and highlight the changing treatment landscape of advanced bladder cancer. In addition, commonly expressed molecular targets were leveraged to develop targeted therapies, such as fibroblast growth factor receptor inhibitors and antibody-drug conjugates. The molecular characterization of bladder cancer and the development of novel therapies also have stimulated investigations into optimizing treatment approaches for muscle-invasive bladder cancer. Herein, the authors review the history of muscle-invasive and advanced bladder cancer management, highlight the important molecular characteristics of bladder cancer, describe the major advances in treatment, and offer future directions for therapeutic development.

Sulforaphane for the chemoprevention of bladder cancer: molecular mechanism targeted approach

The clinical course for both early and late stage Bladder Cancer (BC) continues to be characterized by significant patient burden due to numerous occurrences and recurrences requiring frequent surveillance strategies, intravesical drug therapies, and even more aggressive treatments in patients with locally advanced or metastatic disease. For these reasons, BC is also the most expensive cancer to treat. Fortunately, BC offers an excellent platform for chemoprevention interventions with potential to optimize the systemic and local exposure of promising agents to the bladder mucosa. However, other than smoking cessation, there is a paucity of research that systematically examines agents for chemoprevention of bladder cancers. Adopting a systematic, molecular-mechanism based approach, the goal of this review is to summarize epidemiological, in vitro, and preclinical studies, including data regarding the safety, bioavailability, and efficacy of agents evaluated for bladder cancer chemoprevention. Based on the available studies, phytochemicals, specifically isothiocyanates such as sulforaphane, present in Brassicaceae or “cruciferous” vegetables in the precursor form of glucoraphanin are: (a) available in standardized formulations; (b) bioavailable- both systemically and in the bladder; (c) observed to be potent inhibitors of BC carcinogenesis through multiple mechanisms; and (d) without toxicities at these doses. Based on available evidence from epidemiological, in vitro, preclinical, and early phase trials, phytochemicals, specifically isothiocyanates (ITCs) such as sulforaphane (SFN) represent a promising potential chemopreventitive agent in bladder cancer.

Anthocyans as tertiary chemopreventive agents in bladder cancer: anti-oxidant mechanisms and interaction with mitomycin C

Bladder cancer is associated with high rates of recurrence making tertiary chemoprevention an attractive intervention strategy. Anthocyanins have been shown to possess chemopreventive properties and are detectable in urine after oral ingestion, with higher concentrations achievable via intravesical administration alongside current chemotherapeutic regimens. Yet their apparent ability to protect against certain DNA damage may in turn interfere with cancer treatments. Our aim was therefore to determine the potential of anthocyanins as chemopreventive agents in bladder cancer, their mode of action and effects, both alone and in combination with mitomycin C (MMC). In this study we showed that mirtoselect, a standardised mixture of anthocyanins, possesses significant anti-proliferative activity, causing growth inhibition and apoptosis in bladder cancer cell lines. The anti-oxidative potential of mirtoselect was examined and revealed significantly fewer H2O2-induced DNA strand breaks, as well as oxidised DNA bases in pre-treated cells. In contrast, endogenous levels of oxidised DNA bases were unaltered. Investigations into the possible protective mechanisms associated with these anti-oxidant properties revealed that mirtoselect chelates metal ions. In mirtoselect/MMC combination studies, no adverse effects on measures of DNA damage were observed compared to treatment with MMC alone and there was evidence of enhanced cell death. Consistent with this, significantly more DNA crosslinks were formed in cells treated with the combination. These results show that mirtoselect exerts effects consistent with chemopreventive properties in bladder cancer cell lines and most importantly does so without adversely affecting the effects of drugs used in current treatment regimens. We also provide evidence that mirtoselect's anti-oxidative mechanism of action is via metal ion chelation. Overall these results suggest that mirtoselect could be an effective chemopreventive agent in bladder cancer and provides the necessary pre-clinical data for future in vivo animal studies and clinical trials.

Incidental Sonographic Detection of Non–Muscle-Invasive Papillary Urothelial Carcinoma in a Low-Risk Patient

This case presentation describes the early diagnosis of an invasive urinary bladder cancer in a woman in her late 60s with no history of cancer, hematuria, dysuria, smoking, or hormone replacement therapy. This was confirmed on histopathology after tumor resection. The case report demonstrates the importance of including scanning the urinary bladder in all pelvic sonography examinations, even in the low-risk population. The following study also discusses the prevalence, etiology, diagnostic tools, prognosis, and treatment of bladder cancer. Different types of bladder tumors, staging, and grading criteria are also described.

Chemoprevention with green propolis green propolis extracted in L-lysine versus carcinogenesis promotion with L-lysine in N-Butyl-N-[4-hydroxybutyl] nitrosamine (BBN) induced rat bladder cancer

PURPOSE

To determine the effects of green propolis extracted in L-lysine (WSDP) and of L- lysine for 40 weeks on induced rat bladder carcinogenesis.

METHODS

The animals (groups I, II, III, IV, V and VI) received BBN during 14 weeks. Group I was treated with propolis 30 days prior received BBN, and then these animals were treated daily with propolis; Groups II and III was treated with subcutaneous and oral propolis (respectively) concurrently with BBN. The animals of Group IV were treated L-lysine; Group V received water subcutaneous; and Group VI received only to BBN. Among the animals not submitted to carcinogenesis induction, Group VII received propolis, Group VIII received L-lysine and Group IX received water.

RESULTS

The carcinoma incidence in Group I was lower than that of control (Group VI). The carcinoma multiplicity in Group IV was greater than in Group VI. All animals treated with L-lysine developed carcinomas, and they were also more invasive in Group IV than in controls. On the other hand, Group VIII showed no bladder lesions.

CONCLUSION

The WSDP is chemopreventive against rat bladder carcinogenesis, if administered 30 days prior to BBN , and that L-lysine causes promotion of bladder carcinogenesis.

Characteristic patterns of microRNA expression in human bladder cancer

MicroRNAs (miRNAs) are small, non-coding RNAs that post-transcriptionally regulate gene expression. Their altered expression and functional activity have been observed in many human cancers. miRNAs represent promising diagnostic and prognostic molecular biomarkers, and also serve as novel therapeutic targets. We performed a systematic analysis of scientific reports that link differences in miRNA expression with the pathogenesis of bladder cancer (BC). This literature review is the first comprehensive database of miRNA molecules with biased expression profiles in BC. Among the 95 differentially expressed miRNAs that we identified from the literature, we classify 48 as up-regulated in BC, 35 as down-regulated, and 12 as contradictory (contradictory data were reported in one or more studies on the gene). In addition, we discuss the possible roles of differentially expressed miRNAs in the regulation of intracellular signaling pathways in BC.

Functional and molecular characterization of kinin B1 and B 2 receptors in human bladder cancer: implication of the PI3Kγ pathway

Kinins and their receptors have been recently implicated in cancer. Using functional and molecular approaches, we investigated the relevance of kinin B1 and B2 receptors in bladder cancer. Functional studies were conducted using bladder cancer cell lines, and human biopsies were employed for molecular studies. Both B1 des-Arg(9)-BK and B2 BK receptor agonists stimulated the proliferation of grade 3-derived T24 bladder cancer cells. Furthermore, treatment with B1 and B2 receptor antagonists (SSR240612 and HOE140) markedly inhibited the proliferation of T24 cells. Only higher concentrations of BK increased the proliferation of the grade 1 bladder cancer cell line RT4, while des-Arg(9)-BK completely failed to induce its proliferation. Real-time PCR revealed that the mRNA expression of kinin receptors, particularly B1 receptors, was increased in T24 cells relative to RT4 cells. Data from bladder cancer human biopsies revealed that B1 receptor expression was increased in all tumor samples and under conditions of chronic inflammation. We also show novel evidence demonstrating that the pharmacological inhibition of PI3Kγ (phosphatidylinositol 3-kinase) with AS252424, concentration-dependently reduced T24 cell proliferation induced by BK or des-Arg(9)-BK. Finally, the incubation of T24 cells with kinin agonists led to a marked activation of the PI3K/AKT and ERK 1/2 signaling pathways, whereas p38 MAP kinase remained unaffected. Kinin receptors, especially B1 receptors, appear to be implicated in bladder cancer progression. It is tempting to suggest that selective kinin antagonists might represent potential alternative therapies for bladder cancer.

A phase 2 cancer chemoprevention biomarker trial of isoflavone G-2535 (genistein) in presurgical bladder cancer patients

The soy compound genistein has been observed preclinically to inhibit bladder cancer growth with one potential mechanism being the inhibition of epidermal growth factor receptor phosphorylation (p-EGFR). A phase 2 randomized, placebo-controlled trial investigated whether daily, oral genistein (300 or 600 mg/d as the purified soy extract G-2535) for 14 to 21 days before surgery alters molecular pathways in bladder epithelial tissue in 59 subjects diagnosed with urothelial bladder cancer (median age, 71 years). G-2535 treatment was well tolerated; observed toxicities were primarily mild to moderate gastrointestinal or metabolic and usually not attributed to study drug. Genistein was detected in plasma and urine of subjects receiving G-2535 at concentrations greater than placebo subjects' but were not dose-dependent. Reduction in bladder cancer tissue p-EGFR staining between the placebo arm and the combined genistein arms was significant at the protocol-specified significance level of 0.10 (P = 0.07). This difference was most prominent when comparing the 300-mg group with placebo (P = 0.015), but there was no significant reduction in p-EGFR staining between the 600-mg group and placebo. No difference in normal bladder epithelium p-EGFR staining was observed between treatment groups. No significant differences in tumor tissue staining between treatment groups were observed for COX-2, Ki-67, activated caspase-3, Akt, p-Akt, mitogen-activated protein kinase (MAPK), or p-MAPK. No significant differences in urinary survivin or BLCA-4 levels between treatment groups were observed. Genistein displayed a possible bimodal effect (more effective at the lower dose) on bladder cancer tissue EGFR phosphorylation that should be evaluated further, possibly in combination with other agents.

Urothelial carcinoma of the bladder: definition, treatment and future efforts

The identification of patients with high-risk bladder cancer is important for the timely and appropriate treatment of this lethal disease. The understanding of the natural history of bladder cancer has improved; however, the criteria used to define high-risk disease and the relevant treatment strategies have remained the same for the past several decades, despite multiple large, randomized, prospective clinical trials that have evaluated the use of intravesical, surgical and systemic therapies. The genetic signature of high-risk bladder cancer has been a focus of investigation and has led to the discovery of potential molecular targets for disease identification, risk stratification and therapy. These advances, combined with a comprehensive risk assessment profile that incorporates available pathological and clinical characteristics, might improve the diagnosis and treatment of patients with bladder cancer.

A randomized controlled trial of celecoxib to prevent recurrence of nonmuscle-invasive bladder cancer

Significant morbidity and expense result from frequent recurrences of nonmuscle-invasive bladder cancer (NMIBC) after standard treatment, and carcinoma in situ (Tis) is a poor prognostic factor. Predicated on observational and preclinical data strongly supporting cyclooxygenase-2 (COX-2) in the pathogenesis, and the activity of COX-2 inhibitors, in bladder cancer, we conducted a randomized, double-blind, placebo-controlled trial to determine whether celecoxib could reduce the time-to-recurrence (TTR) in NMIBC patients at high risk for recurrence. A total of 146 patients were randomized to celecoxib (200 mg) or placebo orally twice daily for at least 12 months. The average treatment duration was 1.25 years. Primary intent-to-treat analysis revealed celecoxib did not statistically significantly prolong TTR compared with placebo (P = 0.17, log rank) with a median follow-up of 2.49 years. The recurrence-free rate at 12 months with celecoxib was 88% (95% CI: 0.81-0.96) versus 78% (95% CI: 0.69-0.89) with placebo. After controlling for covariates with Cox regression analysis, recurrence rates did not differ between the two study arms (HR = 0.69; 95% CI: 0.37-1.29). However, celecoxib had a marginally significant effect on reducing metachronous recurrences (vs. placebo) with HR of 0.56 (95% CI: 0.3-1.06; P = 0.075). Celecoxib was well tolerated, with similar adverse events and quality-of-life in both arms. Our clinical trial results do not show a clinical benefit for celecoxib in preventing NMIBC recurrence but further investigation of COX-2 inhibitors in this setting is warranted.

Rhodiola rosea extracts and salidroside decrease the growth of bladder cancer cell lines via inhibition of the mTOR pathway and induction of autophagy

The incidence of human urinary bladder cancer increases markedly with age, suggesting a mechanistic connection between aging and bladder carcinogenesis and a potential use of anti-aging agents in bladder cancer chemoprevention. Rhodiola rosea, growing in high altitude or cold regions of the world, has been reported to have anti-aging effects in Drosophila. We demonstrated that a R. rosea extract and one of its bioactive components, salidroside, inhibited the growth of bladder cancer cell lines with a minimal effect on nonmalignant bladder epithelial cells TEU-2. Interestingly, the R. rosea extract and salidroside component exhibited a selective ability to inhibit the growth of p53 knockout primary mouse embryo fibroblasts (p53-/- MEFs) compared to their wild-type counterparts. The growth inhibitory effects of the R. rosea extract and salidroside were, however, attenuated in TSC2 and p53 double knock MEFs (TSC2-/-, p53-/- MEFs), suggesting that TSC2 protein is, at least in part, required for the growth inhibitory effects of the R. rosea extract and salidroside. The R. rosea extract and salidroside treatment of UMUC3 cells resulted in an increase of AMP-activated protein kinase (AMPK)-α phosphorylation and a decrease of 4E-BP1 phosphorylation, leading to increased binding of 4E-BP1 to m7 GTP. These results indicate that the R. rosea extract and salidroside inhibit translation initiation. Furthermore, both the R. rosea extract and salidroside treatment of UMUC3 cells caused a significant percentage of cells undergoing autophagy. Therefore, the R. rosea extract and salidroside deserve further study as novel agents for chemoprevention of bladder carcinogenesis.

Personalized therapy for urothelial cancer: review of the clinical evidence

Despite a detailed understanding of the molecular aberrations driving the development of urothelial cancers, this knowledge has not translated into advances for the treatment of this disease. Urothelial cancers are chemosensitive, and platinum-based combination chemotherapy remains the standard of care for advanced disease, as well as neoadjuvant and adjuvant therapy for locally advanced disease. However, nearly half of patients who undergo resection of locally advanced urothelial cancer will relapse and eventually develop platinum-resistant disease. Clinical trials of targeted agents against angiogenesis and growth factors, as well as novel chemotheraputics, have generally been unsuccessful in urothelial cancers. Improvements in the theraputic arsenal for urothelial cancer depend upon identification of new targets and strategies to overcome platinum resistance.

BCAN Think Tank session 3: Prevention of bladder cancer

The Bladder Cancer Think Tank III brought together a multidisciplinary group of clinician scientists, patient advocates, representatives from the National Cancer Institute, and Industry leaders to discuss the current state of the field in urothelial cancer and to develop strategies to move forward. This paper summarizes the session devoted to prevention. Experts sought to define primary, secondary, and tertiary prevention and discussed clinical trials performed to date testing retinoids, difluoromethylornithine, celecoxib, and other oral agents in a tertiary prevention setting following transurethral resection with or without intravesical therapy. Urologists practice tertiary prevention in the form of intravesical therapy, and strategies were discussed to identify biomarkers, including urinary cytokines and pathway single nucleotide polymorphism analysis associated with response to treatment. Optimizing delivery of intravesical chemotherapy to the target tissue with simple pharmacologic manipulations or packaging drugs in nanoparticles may improve treatment outcome. Defining a premalignant lesion should be a focus of future research as a strategy for early detection and secondary prevention. Cigarette smoking is the most prevalent risk factor for urothelial cancer, and emphasis was placed on smoking cessation as a powerful tool to reduce the burden of urothelial cancer, and the central role physicians must play in educating patients and providing resources. There is a strong need for research to develop markers of disease initiation and progression. These markers, combined with histories of environmental exposure to bladder carcinogens, may provide a tool to identify patients who will benefit from primary prevention.

Loss of 15-hydroxyprostaglandin dehydrogenase expression contributes to bladder cancer progression

Prostaglandin E2, which is known to contribute to cancer progression, is inactivated by the catabolic enzyme, 15-hydroxyprostaglandin dehydrogenase (PGDH), which has tumor-suppressor activity in lung, colon, breast, and gastric cancers. Therefore, we evaluated the expression of PGDH in human bladder cancer tissue specimens and cell lines. Immunoperoxidase staining of bladder cancer tissues demonstrated that (1) PGDH is highly expressed by normal urothelial cells but (2) reduced in many low stage (Ta/Tis) bladder cancers, and (3) PGDH is completely lost in most invasive bladder cancers. Of eight cancer cell lines tested, only two relatively well-differentiated bladder cancer cell lines, RT4 and UM-UC9, expressed PGDH. Moreover, inhibition of PGDH expression in well-differentiated RT4 cells using small inhibitory RNA or short hairpin RNA resulted in a more aggressive phenotype with increased motility and anchorage-independent growth. Additionally, PGDH knockdown affected prostaglandin E2 signaling as measured by cAMP generation. These data indicate that loss of PGDH expression contributes to a more malignant bladder cancer phenotype and may be necessary for bladder cancer development and/or progression.