Localized and locally advanced bladder cancer

Natural products as a means of overcoming cisplatin chemoresistance in bladder cancer

Cisplatin remains an integral part of the treatment for muscle invasive bladder cancer. A large number of patients do not respond to cisplatin-based chemotherapy and efficacious salvage regimens are limited. Immunotherapy has offered a second line of treatment; however, only approximately 20% of patients respond, and molecular subtyping of tumors indicates there may be significant overlap in those patients that respond to cisplatin and those patients that respond to immunotherapy. As such, restoring sensitivity to cisplatin remains a major hurdle to improving patient care. One potential source of compounds for enhancing cisplatin is naturally derived bioactive products such as phytochemicals, flavonoids and others. These compounds can activate a diverse array of different pathways, many of which can directly promote or inhibit cisplatin sensitivity. The purpose of this review is to understand current drug development in the area of natural products and to assess how these compounds may enhance cisplatin treatment in bladder cancer patients.

New agents for bacillus Calmette-Guérin-refractory nonmuscle invasive bladder cancer

PURPOSE OF REVIEW

Radical cystectomy is the standard of care for patients who fail intravesical bacillus Calmette-Guérin (BCG) for nonmuscle invasive bladder cancer (NMIBC). For patients unwilling or unable to undergo cystectomy, numerous local therapies exist, although few are approved by the Food and Drug Administration. This review describes available therapies for this challenging clinical entity.

RECENT FINDINGS

Combination intravesical chemotherapy, targeted therapy, and drug delivery enhancement have all been under recent investigation and are promising, although none has proven superior as of yet.

SUMMARY

While BCG is standard treatment for intermediate and high-risk NMIBC, many patients fail therapy with recurrence or progression. Early cystectomy is the standard of care for BCG failure; however, many patients are unwilling or unable to undergo cystectomy. Multiple intravesical therapies have been used in this BCG failure population with moderate success, and, recently, technologies to improve drug delivery or create novel drugs have also been applied. Comparing efficacy of these therapies remain challenging as study cohorts are heterogeneous and study designs are variable. However, there are an increasing number of novel treatment options that can be offered to patients faced with recurrent NMIBC after BCG who seek bladder-sparing therapy.

The src-family kinase inhibitor PP2 suppresses the in vitro invasive phenotype of bladder carcinoma cells via modulation of Akt

OBJECTIVE

To evaluate PP2 as a modulator of the cadherin/catenin complex in late-stage bladder carcinoma cells, and to assess its potential invasion-suppressor activity in this model.

MATERIALS AND METHODS

A panel of five human bladder carcinoma cells, characterizing late-stage disease, was used to determine the concentration for 50% inhibition of PP2 in cell-proliferation assays. Modulation of cadherin/catenin expression by PP2 was determined in Western blot analysis, with an assessment of the activation status of mitogen-activated protein kinase and Akt signalling pathways. Altered invasive capacity linked to these variables was determined in standard in vitro invasion assays.

RESULTS

PP2 elicited concentration-dependent growth inhibition in all bladder cell lines within the panel, with growth suppression recorded at 10-35 micromol/L PP2. Distinct morphological changes were recorded in cell lines exposed to PP2, accompanied by up-regulation of plakoglobin expression in a subset of lines. Exposure of cells to PP2 resulted in inactivation of Akt in all cells and a concomitant reduction in in vitro invasive capacity.

CONCLUSIONS

These results show that PP2 inhibits bladder carcinoma cell growth and can modulate plakoglobin expression in a subset of cell lines. In addition, PP2 can suppress the in vitro invasive capacity of bladder carcinoma cells by modulating the activation status of Akt.

Molecular detection of noninvasive and invasive bladder tumor tissues and exfoliated cells by aberrant promoter methylation of laminin-5 encoding genes

Laminin-5 (LN5) anchors epithelial cells to the underlying basement membrane, and it is encoded by three distinct genes: LAMA3, LAMB3, and LAMC2. To metastasize and grow, cancer cells must invade and destroy the basement membrane. Our previous work has shown that epigenetic inactivation is a major mechanism of silencing LN5 genes in lung cancers. We extended our methylation studies to resected bladder tumors (n = 128) and exfoliated cell samples (bladder washes and voided urine; n = 71) and correlated the data with clinicopathologic findings. Nonmalignant urothelium had uniform expression of LN5 genes and lacked methylation. The methylation frequencies for LN5 genes in tumors were 21-45%, and there was excellent concordance between methylation in tumors and corresponding exfoliated cells. Methylation of LAMA3 and LAMB3 and the methylation index were correlated significantly with several parameters of poor prognosis (tumor grade, growth pattern, muscle invasion, tumor stage, and ploidy pattern), whereas methylation of LAMC2 and methylation index were associated with shortened patient survival. Of particular interest, methylation frequencies of LAMA3 helped to distinguish invasive (72%) from noninvasive (12%) tumors. These results suggest that methylation of LN5 genes has potential clinical applications in bladder cancers.