Novel therapeutics in the treatment of bladder cancer

Association Between Serum Cadmium and Arsenic Levels with Bladder Cancer: A Case-control Study

Background: Bladder cancer is the second most common cancer of the genitourinary system and the eighth cause of cancer death. In addition to known risk factors such as smoking and urinary stones, trace elements are also effective in causing bladder cancer and other cancers. Objectives: This study was conducted to determine the association between bladder cancer and the carcinogens cadmium and arsenic. Methods: This case-control study was conducted on 40 patients with bladder cancer admitted to Shahid Bahonar Hospital and a control group of 40 healthy individuals in Kerman, Iran, in 2018. The serum levels of arsenic and cadmium were measured by atomic absorptiometry. The paired t-test and chi-square tests were employed to assess the difference between cases and controls groups. An unadjusted and 2 multivariable conditional regression models were separately adjusted on sex, family cancer history, residence, occupation, and smoking and were used to estimate odds ratios (OR) and 95% confidence intervals (95% CI) to assess the association between arsenic and cadmium levels and bladder cancer. The statistical software SPSS version 26 and R software version 3.6.3 were used to perform the statistical analyses. Results: The mean cadmium level was 2.99 ± 1.45 and 2.59 ± 0.46 in the case and control groups, respectively, with no statistically significant difference between the groups (P = 0.100). The mean arsenic level was 2.12 ± 1.04 and 1.43 ± 0.73 in the case and control groups, respectively, demonstrating a statistically significant difference between the groups (P = 0.001). Unadjusted and adjusted conditional logistic regression models indicated significant association between arsenic levels and bladder cancer (unadjusted: odds ratio (OR) (95% CI): 0.66 (0.46 - 0.94), P-value = 0.022; adjusted: OR (95% CI): 0.64 (0.44 - 0.92), P-value = 0.018). Conclusions: Overall, cadmium and arsenic levels are higher in patients with bladder cancer, with a statistically significant difference for arsenic. However, these elements are not interrelated and are not related to other factors.

Construction of a BALB/c-Nu Mouse Model of Invasive Bladder Carcinoma and Preliminary Studies on the Treatment of Bladder Tumors through Internal Iliac Arterial Infusion of Albumin-Bound Arsenic Trioxide (As2O3)

To establish a BALB/c-nu mouse model of invasive bladder carcinoma and to investigate the feasibility, efficacy, and side effects of treating the mouse xenografts with internal iliac arterial infusion of albumin-bound arsenic trioxide (As2O3). Bladder tumors were established by intravesicular injection. Color Doppler were used to monitor tumor growth. Albumin-bound As2O3 and bovine serum albumin (BSA) nanoparticles were synthesized by cross-linking. BALB/c-nu mice were randomly divided into four treatment groups: 1) normal saline, 2) BSA nanoparticles, 3) As2O3 injections, and 4) albumin-bound As2O3. In an attempt to replicate the treatment of bladder cancer in humans using internal iliac arterial infusion, the drugs were injected into the mouse abdominal aorta. Tumor xenografts were established successfully. Mice treated with As2O3 injections and with albumin-bound As2O3 had significantly smaller bladders (36.59% and 37.82% smaller, respectively) than mice given normal saline injections (P < 0.01). Mice receiving As2O3 injections had lower white blood cell (WBC) and platelet counts compared with mice receiving normal saline injections only (P < 0.05). However, mice treated with albumin-bound As2O3 did not experience a significant decrease in WBC or platelet counts compared with control mice. A model of intra-arterial bladder cancer treatment was successfully established in BALB/c-nu mice. In this model, albumin-bound As2O3 appeared to be an effective method for treating bladder tumors, with less severe hematologic side effects compared with As2O3 alone. The infusion of albumin-bound As2O3 through the internal iliac artery is a promising method of bladder cancer therapy.

Outcome of surgical resection of pulmonary metastasis from urinary tract transitional cell carcinoma

There is little information on pulmonary metastasectomy of urinary tract transitional cell carcinoma (TCC). In this study, we examined the long-term outcome and the factors associated with long-term survival after pulmonary metastasectomy of urinary tract TCC based on a 20-year single center experience. Between 1984 and 2005, 18 patients (12 men, six women) underwent pulmonary metastasectomy of the urinary tract TCC in our hospital. The clinicopathological and surgical data of these patients obtained from the medical records were analyzed in this retrospective study. The time interval between lung resection and death, or latest follow-up ranged from two to 200 months (median 52). Survival analysis was conducted by the Kaplan-Meier method and log-rank test. The cumulative three- and five-year survival rates were 59.8% and 46.5%, respectively. The number of resected metastatic tumors (solitary vs. multiple) was associated with long-term survival (P<0.05). The five-year survival rate of patients with solitary metastasis was 85.7% while that of patients with multiple metastases was 20.0%. Pulmonary metastasectomy of urinary tract TCC is associated with a favorable outcome, and solitary metastasis is associated with long-term survival. Aggressive management of solitary pulmonary metastasis from a urinary tract TCC is feasible in selected patients.

Intravesical delivery of rapamycin suppresses tumorigenesis in a mouse model of progressive bladder cancer

Early-stage bladder cancer occurs as two distinct forms: namely, low-grade superficial disease and high-grade carcinoma in situ (CIS), which is the major precursor of muscle-invasive bladder cancer. Although the low-grade form is readily treatable, few, if any, effective treatments are currently available for preventing progression of nonmuscle-invasive CIS to invasive bladder cancer. Based on our previous findings that the mammalian target of Rapamycin (mTOR) signaling pathway is activated in muscle-invasive bladder cancer, but not superficial disease, we reasoned that suppression of this pathway might block cancer progression. To test this idea, we performed in vivo preclinical studies using a genetically engineered mouse model that we now show recapitulates progression from nonmuscle-invasive CIS to muscle-invasive bladder tumors. We find that delivery of Rapamycin, an mTOR inhibitor, subsequent to the occurrence of CIS effectively prevents progression to invasive bladder cancer. Furthermore, we show that intravesical delivery of Rapamycin directly into the bladder lumen is highly effective for suppressing bladder tumorigenesis. Thus, our findings show the potential therapeutic benefit of inhibiting mTOR signaling for treatment of patients at high risk of developing invasive bladder cancer. More broadly, our findings support a more widespread use of intravesical delivery of therapeutic agents for treatment of high-risk bladder cancer patients, and provide a mouse model for effective preclinical testing of potential novel agents.

[Complete resection of urothelial cancer metastases with curative intent]

BACKGROUND

Recent publications suggest that a subgroup of patients can benefit from surgical removal of transitional cell carcinoma (TCC) metastases in addition to systemic chemotherapy. We report the combined experience and outcome of patients undergoing resection of TCC metastases at 15 uro-oncologic centers in Germany.

MATERIALS AND METHODS

Forty-four patients with distant metastatic TCC of the bladder or upper urinary tract underwent resection of all detectable metastases in 15 different German uro-oncological centers between 1991 and 2008 in an attempt to be rendered free of disease.

RESULTS

The resected metastatic sites consisted of retroperitoneal lymph nodes (56.8%), distant lymph nodes (11.3%), lung (18.2%), bone (4.5%), adrenal gland (2.3%), brain (2.3%), small intestine (2.3%), and skin (2.3%). The treatment sequence included systemic chemotherapy in 35/44 (79.5%) patients before and/or after surgery. Median survival times from initial diagnosis of metastatic TCC and subsequent resection were as follows: overall survival, 35 and 27 months, respectively; cancer-specific survival, 38 and 34 months, respectively; and progression-free survival, 19 and 15 months, respectively. Overall 5-year survival from metastasectomy for the entire cohort was 28%. Seventeen patients were still alive without progression at a median follow-up time of 8 months. Seven patients without disease progression survived for more than 2 years and remain free from tumor progression at a median of 63 months.

CONCLUSION

The results in this selected cohort confirm that long-term cancer control and possibly cure can be achieved in a subgroup of patients following surgical removal of TCC metastases. However, prospective data to identify patients most likely to benefit from this aggressive therapeutic approach are lacking. Therefore, metastasectomy in patients with disseminated TCC remains investigational and should be offered only to those with limited disease as a combined-modality approach with systemic chemotherapy.

The comparative study of serum iron, copper, and zinc levels between bladder cancer patients and a control group

OBJECTIVE

A relatively wide range of trace elements are known to play important roles in biological processes, including the oxidative processes. Oxidative processes are one of the mechanisms involved in both incidence and recurrence of bladder cancer. In the present study, the concentration of iron (Fe), copper (Cu) and zinc (Zn) were determined in the serum of patients with bladder cancer in comparison to healthy subjects.

MATERIALS AND METHODS

This cross-sectional study was conducted on 51 patients with bladder cancer and 58 healthy volunteers after age, sex, and smoking habits were matched. After overnight fasting, samples were collected. The concentrations of Fe, Cu, and Zn were measured by flame atomic absorption spectroscopy and comparisons were made using Student's t-test.

RESULTS

There was a significant increase in mean Cu and Cu/Zn serum level in bladder cancer patients compared to the control group (P < 0.001). In contrast, the serum zinc level in patients having bladder cancer was significantly lower than in the control group (P < 0.05). Moreover, the serum iron level was significantly lower in the patients than the control group (P < 0.001).

CONCLUSIONS

In the present study, a relationship was seen between the level of trace elements and the occurrence of bladder cancer, suggesting that an increase in the serum level of Cu and a decrease in the levels of Zn and Fe might be important causes of bladder cancer occurrence; however, defining such a cause-and-effect relationship needs several prospective studies to be done, which seems necessary with regard to the high prevalence of this cancer.

Inactivation of p53 and Pten promotes invasive bladder cancer

Although bladder cancer represents a serious health problem worldwide, relevant mouse models for investigating disease progression or therapeutic targets have been lacking. We show that combined deletion of p53 and Pten in bladder epithelium leads to invasive cancer in a novel mouse model. Inactivation of p53 and PTEN promotes tumorigenesis in human bladder cells and is correlated with poor survival in human tumors. Furthermore, the synergistic effects of p53 and Pten deletion are mediated by deregulation of mammalian target of rapamycin (mTOR) signaling, consistent with the ability of rapamycin to block bladder tumorigenesis in preclinical studies. Our integrated analyses of mouse and human bladder cancer provide a rationale for investigating mTOR inhibition for treatment of patients with invasive disease.

Improving Efficacy of Intravesical Chemotherapy

OBJECTIVE

This paper reviews the most relevant findings published recently on intravesical chemotherapy for superficial bladder tumours and provides recommendations based on documented research.

METHODS

The evidence was categorised according to the North of England Evidence Based Guideline Development Project. Levels of evidence were based on the source of the information, meta-analyses, systematic reviews, well-designed randomised or nonrandomised controlled clinical trials, and uncontrolled studies or consensus. Three levels of recommendations were assigned to the evidence obtained.

RESULTS

Despite intravesical chemotherapy being used prophylactically after endoscopic resection of superficial bladder tumours, the recurrence rate is still 36-44%. Researchers have focused on improving the effectiveness of intravesical chemotherapy, each adopting a different strategy. Some have aimed to identify the optimum timing for instillations and others to improve the pharmacokinetics of agents by avoiding their dilution, increasing their stability, or improving the absorption of the drug by bladder mucosa. Some researchers are looking into new, single chemotherapeutic agents or combinations for intravesical use and others into avoiding chemoresistance with resistance-reverting agents (modulating agents) or by using in vitro chemosensitivity tests to identify the most sensitive drug.

CONCLUSION

Progress has been made in optimising intravesical chemotherapy for timing of instillations and pharmacokinetic interventions. Simple and inexpensive approaches may have a widespread, practical acceptance by urologists, but it is more difficult to extend new techniques requiring more complex and sometimes expensive instrumentation to the urologic community. Further research into finding more effective cytotoxic drugs, combinations, or modulating agents should be encouraged.

Antisense oligodeoxynucleotide therapy for bladder cancer: recent advances and future prospects

Despite remarkable progress in therapeutic options for the management of bladder cancer, it remains a challenge for urologists to achieve successful outcomes in the treatment of both superficial and invasive bladder cancers. In this review, recent advances in the field of antisense oligodeoxynucleotide therapy targeting several genes playing functionally important roles in the progression and recurrence of bladder cancer are summarized. Data showing the synergistic antitumor activities of antisense oligodeoxynucleotide therapy, combined with several treatments, including cytotoxic chemotherapy, radiation and other molecular targeting therapies, are also presented. Finally, the future direction of antisense oligodeoxynucleotide therapy in the therapeutic strategy of bladder cancer is discussed. These findings may help clarify the significance of antisense oligodeoxynucleotide therapy as an attractive alternative to conventional strategies.