Selective cytotoxicity of gemcitabine in bladder cancer cell lines

Intravesical gemcitabine for non-muscle invasive bladder cancer

BACKGROUND

It remains unclear whether people with non-muscle invasive bladder cancer (NMIBC) benefit from intravesical gemcitabine compared to other agents in the primary or recurrent setting following transurethral resection of a bladder tumor. This is an update of a Cochrane Review first published in 2012. Since that time, several randomized controlled trials (RCTs) have been reported, making this update relevant.  OBJECTIVES: To assess the comparative effectiveness and toxicity of intravesical gemcitabine instillation for NMIBC.

SEARCH METHODS

We performed a comprehensive literature search of the Cochrane Library, MEDLINE, Embase, four other databases, trial registries, and conference proceedings to 11 September 2020, with no restrictions on the language or status of publication.

SELECTION CRITERIA

We included RCTs in which participants received intravesical gemcitabine for primary or recurrent NMIBC.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed the included studies and extracted data for the primary outcomes: time to recurrence, time to progression, grade III to V adverse events determined by the Common Terminology Criteria for Adverse Events version 5.0 (CTCAE v5.0), and the secondary outcomes: time to death from bladder cancer, time to death from any cause, grade I or II adverse events determined by the CTCAE v5.0 and disease-specific quality of life. We performed statistical analyses using a random-effects model and rated the certainty of the evidence using GRADE.

MAIN RESULTS

We included seven studies with 1222 participants with NMIBC across five comparisons. This abstract focuses on the primary outcomes of the three most clinically relevant comparisons. 1. Gemcitabine versus saline: based on two years' to four years' follow-up, gemcitabine may reduce the risk of recurrence over time compared to saline (39% versus 47% recurrence rate, hazard ratio [HR] 0.77, 95% confidence interval [CI] 0.54 to 1.09; studies = 2, participants = 734; I2 = 49%; low-certainty evidence), but the CI included the possibility of no effect.  Gemcitabine may result in little to no difference in the risk of progression over time compared to saline (4.6% versus 4.8% progression rate, HR 0.96, 95% CI 0.19 to 4.71; studies = 2, participants = 654; I2 = 53%; low-certainty evidence).  Gemcitabine may result in little to no difference in the CTCAE grade III to V adverse events compared to saline (5.9% versus 4.7% adverse events rate, risk ratio [RR] 1.26, 95% CI 0.58 to 2.75; studies = 2, participants = 668; I2 = 24%; low-certainty evidence).  2. Gemcitabine versus mitomycin: based on three years' follow-up (studies = 1, participants = 109), gemcitabine may reduce the risk of recurrence over time compared to mitomycin (17% versus 40% recurrence rate, HR 0.36, 95% CI 0.19 to 0.69; low-certainty evidence). Gemcitabine may reduce the risk of progression over time compared to mitomycin (11% versus  18% progression rate, HR 0.57, 95% CI 0.32 to 1.01; low-certainty evidence), but the CI included the possibility of no effect.  We are very uncertain about the effect of gemcitabine on the CTCAE grade III to V adverse events compared to mitomycin (RR 0.51, 95% CI 0.13 to 1.93; very low-certainty evidence). The analysis was only based on recurrent NMIBC. 3. Gemcitabine versus Bacillus Calmette-Guérin (BCG) for recurrent (one-course BCG failure) high-risk NMIBC: based on 6 months' to 22 months' follow-up (studies = 1, participants = 80), gemcitabine may reduce the risk of recurrence compared to BCG (41% versus 97% recurrence rate, HR 0.15, 95% CI 0.09 to 0.26; low-certainty evidence) and progression over time (16% versus 33% progression rate, HR 0.45, 95% CI 0.27 to 0.76; low-certainty evidence). We are very uncertain about the effect of gemcitabine on the CTCAE grade III to V adverse events compared to BCG (RR 1.00, 95% CI 0.21 to 4.66; very low-certainty evidence).  In addition, the review provides information on  the comparison of gemcitabine versus BCG and gemcitabine versus one-third dose BCG.  AUTHORS' CONCLUSIONS: Based on findings of this review, gemcitabine may have a more favorable impact on recurrence and progression-free survival than mitomycin but we are very uncertain as to how major adverse events compare. The same is true when comparing gemcitabine to BCG in individuals with high risk disease who have previously failed BCG. The underlying low- to very low-certainty evidence indicates that our confidence in these results is limited; the true effects may be substantially different from these findings; therefore, better quality studies are needed.

Oblongifolin C reverses GEM resistance via suppressing autophagy flux in bladder cancer cells

A number of previous studies have demonstrated that inhibiting autophagy can increase the cellular cytotoxicity of chemotherapeutic agents in urothelial cancer cells. However, the mechanistic roles of autophagy in gemcitabine (GEM) resistant bladder cancer cells have not been thoroughly investigated. In the present study, immunohistochemistry staining of autophagy marker LC3 was performed in bladder cancer and healthy control tissues and demonstrated an essential role of autophagy in cancer development. A GEM-resistant cell line was established to assess the effects of autophagy on the acquisition of GEM resistance. Western blotting of autophagy markers in GEM-resistant bladder cancer cells suggested that GEM resistance was caused, at least partially, by GEM-induced autophagy. GEM resistance was demonstrated to be reversed by the inhibition of autophagy by 3-methyladenine. In addition, oblongifolin C (OC), a novel autophagic flux inhibitor purified from traditional Chinese medicine, was found to enhance the efficiency of GEM in GEM-resistant bladder cancer cells by inhibiting autophagic flux. In conclusion, data from the present study suggest that autophagy serves an important role in bladder cancer development and GEM resistance. OC treatment has the ability to reverse GEM-resistance in bladder cancer cells by suppressing autophagic flux, thereby providing a potential adjunctive therapeutic option for bladder cancer GEM treatment.

Inhibition of autophagy by chloroquine enhances the antitumor activity of gemcitabine for gallbladder cancer

Gemcitabine (GEM), as an anti-metabolic nucleoside analog, has been shown to have anticancer effects in various tumors, but its chemotherapy resistance is still an important factor leading to poor prognosis of cancer patient. A large number of studies in recent years have shown that autophagy plays an important role in the chemotherapy sensitivity of many tumors, including pancreatic, non-small cell lung, and bladder cancer. However, whether GEM causes autophagy in gallbladder cancer (GBC) and whether it is related to chemotherapy resistance is unknown. In the present study, we demonstrated that GEM induced apoptosis and protective autophagy in GBC cells, which may be related to the AKT/mTOR signaling pathway, and GEM in combination with autophagy inhibitor chloroquine can strengthen the cytotoxic effect of GEM on GBC in vitro and in vivo. These findings showed that both autophagy and AKT/mTOR signals were engaged in GBC cell death evoked by GEM, GBC patients might benefit from this new treatment strategy, and molecular targeted treatment in combination with autophagy inhibitors shows promise as a treatment improvement.

Apaziquone for Nonmuscle Invasive Bladder Cancer: Where Are We Now?

Apaziquone is an interesting drug for intravesical use in patients with nonmuscle invasive bladder cancer; however, more research is needed to prove its actual benefit. Although the apaziquone trials demonstrate the potential of this new drug, the singular phase 3 trials did not reach their primary endpoint. To date, no new trials are recruiting, so the development of apaziquone seems to have stopped.

Modeling human bladder cancer

INTRODUCTION

Bladder cancer is a major public health concern and the treatment options available are unable to significantly prevent disease recurrence and progression. The need for experimental tumor models to efficiently reproduce the pathology of human cancers has prompted researchers to attempt various approaches.

METHODS

A PubMed search combining the MeSH bladder cancer and models was executed in March 2017.

RESULTS

We review the advantages and limitations of currently available in vitro 2D and 3D bladder cancer models as well as in vivo rodent models. To date, despite the description of a variety of animal models (including transplantable, carcinogen-induced and genetically engineered models), the establishment of reliable, simple, practicable and reproducible animal models remains an ongoing challenge. Recently, sophisticated 3D culture systems have been designed to better recapitulate the phenotypic and cellular heterogeneity as well as microenvironmental aspects of in vivo tumor growth, while being more flexible to conduct repeated experiments.

CONCLUSION

Selecting the most appropriate model for a specific application will maximize the conversion of potential therapies from the laboratory to clinical practice and requires an understanding of the various models available.

Loss of tumor suppressor KDM6A amplifies PRC2-regulated transcriptional repression in bladder cancer and can be targeted through inhibition of EZH2

Trithorax-like group complex containing KDM6A acts antagonistically to Polycomb-repressive complex 2 (PRC2) containing EZH2 in maintaining the dynamics of the repression and activation of gene expression through H3K27 methylation. In urothelial bladder carcinoma, KDM6A (a H3K27 demethylase) is frequently mutated, but its functional consequences and therapeutic targetability remain unknown. About 70% of KDM6A mutations resulted in a total loss of expression and a consequent loss of demethylase function in this cancer type. Further transcriptome analysis found multiple deregulated pathways, especially PRC2/EZH2, in KDM6A-mutated urothelial bladder carcinoma. Chromatin immunoprecipitation sequencing analysis revealed enrichment of H3K27me3 at specific loci in KDM6A-null cells, including PRC2/EZH2 and their downstream targets. Consequently, we targeted EZH2 (an H3K27 methylase) and demonstrated that KDM6A-null urothelial bladder carcinoma cell lines were sensitive to EZH2 inhibition. Loss- and gain-of-function assays confirmed that cells with loss of KDM6A are vulnerable to EZH2. IGFBP3, a direct KDM6A/EZH2/H3K27me3 target, was up-regulated by EZH2 inhibition and contributed to the observed EZH2-dependent growth suppression in KDM6A-null cell lines. EZH2 inhibition delayed tumor onset in KDM6A-null cells and caused regression of KDM6A-null bladder tumors in both patient-derived and cell line xenograft models. In summary, our study demonstrates that inactivating mutations of KDM6A, which are common in urothelial bladder carcinoma, are potentially targetable by inhibiting EZH2.

Activation of a c-Jun N-terminal kinase-mediated autophagy pathway attenuates the anticancer activity of gemcitabine in human bladder cancer cells

The role of autophagy in the anticancer activity of gemcitabine (GEM) in bladder cancer is unclear. The aim of this study is to determine whether GEM activates autophagy, the role of autophagy in the anticancer activity of GEM, and the underlying mechanism by which GEM induces autophagy. Human bladder cancer cell lines T24 and BIU87 were treated with GEM in vitro. Cell viability was measured using the Cell Counting Kit-8 assay. Apoptosis was detected by annexin V assay and western blot. Autophagy was measured by western blot and transmission electron microscopy. c-Jun N-terminal kinase (JNK) activation was detected by western blot. Chemical inhibitors were used for intervention of JNK and autophagy. GEM killed bladder cancer cells, which was associated with apoptosis induction. Autophagy was effectively activated by GEM. Suppressing autophagy in GEM-treated cells significantly decreased cell viability, which was associated with increased apoptosis. GEM-induced JNK activation and suppressed B-cell lymphoma 2 expression. The JNK inhibitor SP600125 inhibited GEM-induced autophagy activation and increased GEM's cytotoxicity. GEM kills bladder cancer cells through apoptosis. Meanwhile, JNK-mediated autophagy was activated, which protects the cells against apoptosis. Therefore, inhibition of autophagy could be exploited to enhance the anticancer efficacy of GEM for treating bladder cancer.

Gemcitabine: Selective cytotoxicity, induction of inflammation and effects on urothelial function

Intravesical gemcitabine has recently been introduced for the treatment of superficial bladder cancer and has a favourable efficacy and toxicity profile in comparison to mitomycin c (MMC), the most commonly used chemotherapeutic agent. The aim of this study was to assess the cytotoxic potency of gemcitabine in comparison to MMC in urothelial cell lines derived from non-malignant (UROtsa) and malignant (RT4 and T24) tissues to assess selectivity. Cells were treated with gemcitabine or mitomycin C at concentrations up to the clinical doses for 1 or 2h respectively (clinical duration). Treatment combined with hyperthermia was also examined. Cell viability, ROS formation, urothelial function (ATP, acetylcholine and PGE2 release) and secretion of inflammatory cytokines were assessed. Gemcitabine displayed a high cytotoxic selectivity for the two malignant cell lines (RT4, T24) compared to the non-malignant urothelial cells (UROtsa, proliferative and non-proliferative). In contrast, the cytotoxic effects of MMC were non-selective with equivalent potency in each of the cell lines. The cytotoxic effect of gemcitabine in the malignant cell lines was associated with an elevation in free radical formation and was significantly decreased in the presence of an equilibrative nucleoside transporter inhibitor. Transient changes in urothelial ATP and PGE₂ release were observed, with significant increase in release of interleukin-6, interleukin-8 and interleukin-1β from urothelial cells treated with gemcitabine. The selectivity of gemcitabine for malignant urothelial cells may account for the less frequent adverse urological effects with comparison to other commonly used chemotherapeutic agents.

In vitro models of medulloblastoma: Choosing the right tool for the job

The recently-defined four molecular subgroups of medulloblastoma have required updating of our understanding of in vitro models to include molecular classification and risk stratification features from clinical practice. This review seeks to build a more comprehensive picture of the in vitro systems available for modelling medulloblastoma. The subtype classification and molecular characterisation for over 40 medulloblastoma cell-lines has been compiled, making it possible to identify the strengths and weaknesses in current model systems. Less than half (18/44) of established medulloblastoma cell-lines have been subgrouped. The majority of the subgrouped cell-lines (11/18) are Group 3 with MYC-amplification. SHH cell-lines are the next most common (4/18), half of which exhibit TP53 mutation. WNT and Group 4 subgroups, accounting for 50% of patients, remain underrepresented with 1 and 2 cell-lines respectively. In vitro modelling relies not only on incorporating appropriate tumour cells, but also on using systems with the relevant tissue architecture and phenotype as well as normal tissues. Novel ways of improving the clinical relevance of in vitro models are reviewed, focusing on 3D cell culture, extracellular matrix, co-cultures with normal cells and organotypic slices. This paper champions the establishment of a collaborative online-database and linked cell-bank to catalyse preclinical medulloblastoma research.

In vitro co-culture model of medulloblastoma and human neural stem cells for drug delivery assessment

Physiologically relevant in vitro models can serve as biological analytical platforms for testing novel treatments and drug delivery systems. We describe the first steps in the development of a 3D human brain tumour co-culture model that includes the interplay between normal and tumour tissue along with nutrient gradients, cell-cell and cell-matrix interactions. The human medulloblastoma cell line UW228-3 and human foetal brain tissue were marked with two supravital fluorescent dyes (CDCFDASE, Celltrace Violet) and cultured together in ultra-low attachment 96-well plates to form reproducible single co-culture spheroids (d = 600 μm, CV% = 10%). Spheroids were treated with model cytotoxic drug etoposide (0.3-100 μM) and the viability of normal and tumour tissue quantified separately using flow cytometry and multiphoton microscopy. Etoposide levels of 10 μM were found to maximise toxicity to tumours (6.5% viability) while stem cells maintained a surviving fraction of 40%. The flexible cell marking procedure and high-throughput compatible protocol make this platform highly transferable to other cell types, primary tissues and personalised screening programs. The model's key anticipated use is for screening and assessment of drug delivery strategies to target brain tumours, and is ready for further developments, e.g. differentiation of stem cells to a range of cell types and more extensive biological validation.

Expert review: an update in current and developing intravesical therapies for non-muscle-invasive bladder cancer

Non-muscle-invasive bladder cancer is a highly prevalent disease and recurrences, after initial therapy, are common. Consequently, the healthcare costs for non-muscle-invasive bladder cancer are high. Despite a primary adequate response to adjuvant intravesical treatment, many patients suffer from recurrences, and some even from progression. To date, cystectomy remains the only option for those non-responding patients with high risk of recurrence and progression. Mainly because outcome after progression, in this group, is poor. Therefore, new intravesical therapies are needed. Moreover, new accurate and individual parameters, to distinguish responder from non-responders, will provide additional benefit in clinical decision-making. In this review, current diagnostics and therapies will be discussed. In addition, we will elucidate developing therapies in non-muscle-invasive bladder cancer.

Temsirolimus improves cytotoxic efficacy of cisplatin and gemcitabine against urinary bladder cancer cell lines

OBJECTIVES

To analyze the cytotoxic action of temsirolimus using 3 established human bladder cancer cell lines and to assess whether temsirolimus potentiates the anticancer activity of gemcitabine and cisplatin.

METHODS

Temsirolimus (500, 1,000, 2,000, and 4,000 nM), in isolation, and combined with gemcitabine (100 nM) and cisplatin (2.5 µg/ml), was given to 5637, T24, and HT1376 bladder cancer cell lines. Cell proliferation, autophagy, early apoptosis, and cell cycle distribution were analyzed after a 72-hour period. The expression of mammalian target of rapamycin baseline, Akt, and their phosphorylated forms, before and after treatment with temsirolimus, was evaluated by immunoblotting.

RESULTS

Temsirolimus slightly decreased the bladder cancer cell proliferation in all 3 cell lines. No significant differences in the expression of mammalian target of rapamycin, Akt, and their phosphorylated forms because of temsirolimus exposure were found in the 3 cell lines. As part of a combined regime along with gemcitabine, and especially with cisplatin, there was a more pronounced antiproliferative effect. This pattern of response was similar to the other parameters analyzed (increased autophagy and apoptosis). Also, in the combined regime, an enhanced cell cycle arrest in the G0/G1 phase was observed. The non-muscle invasive 5637 bladder cancer cell line was most sensitive to both combinations.

CONCLUSIONS

Temsirolimus makes a moderate contribution in terms of cell proliferation, apoptosis, and autophagy. However, it does potentiate the activity of gemcitabine and particularly cisplatin. Therefore, cisplatin- or gemcitabine-based chemotherapy regimen used in combination with temsirolimus to treat bladder cancer represents a novel and valuable treatment option, which should be tested for future studies in urinary bladder xenograft models.

MicroRNA Profile to Predict Gemcitabine Resistance in Bladder Carcinoma Cell Lines

MicroRNAs (miRNA) are small, noncoding RNAs with important regulatory roles in development, differentiation, cell proliferation, and death as well as the complex process of acquired drug resistance. The goal of this study was to identify specific miRNAs and their potential protein targets that confer acquired resistance to gemcitabine in urothelial carcinoma of the bladder (UCB) cell lines. Gemcitabine-resistant cells were established from 6 cell lines following exposure to escalating concentrations of the drug and by passaging cells in the presence of the drug over a 2- to 3-month period. Differential miRNA expression was identified in a microarray format comparing untreated controls with resistant cell lines, representing the maximum tolerated concentration, and results were validated via qRT-PCR. The involvement of specific miRNAs in chemoresistance was confirmed with transfection experiments, followed by clonogenic assays and Western blot analysis. Gemcitabine resistance was generated in 6 UCB cell lines. Microarray analysis comparing miRNA expression between gemcitabine-resistant and parental cells identified the differential expression of 66 miRNAs. Confirmation of differential expression was recorded via qRT-PCR in a subset of these miRNAs. Within this group, let-7b and let-7i exhibited decreased expression, while miR-1290 and miR-138 displayed increased expression levels in gemcitabine-resistant cells. Transfection of pre-miR-138 and pre-miR-1290 into parental cells attenuated cell death after exposure to gemcitabine, while transfection of pre-miR-let-7b and pre-miR-let-7i into the resistant cells augmented cell death. Mucin-4 was up-regulated in gemcitabine-resistant cells. Ectopic expression of let-7i and let-7b in the resistant cells resulted in the down-regulation of mucin-4. These results suggest a role for miRNAs 1290, 138, let-7i, and let-7b in imparting resistance to gemcitabine in UCB cell lines in part through the modulation of mucin-4. Alterations in these miRNAs and/or mucin-4 may constitute a potential therapeutic strategy for improving the efficacy of gemcitabine in UCB.

Perioperative chemotherapy: when to use it, what to use, and why

This article provides an overview of intravesical chemotherapy agents used for non-muscle invasive bladder cancer; summarizes the evidence on single-dose perioperative administration, induction therapy, and maintenance therapy; and briefly discusses ongoing research.

Isolation of mammary epithelial cells from three-dimensional mixed-cell spheroid co-culture

While enormous efforts have gone into identifying signaling pathways and molecules involved in normal and malignant cell behaviors(1-2), much of this work has been done using classical two-dimensional cell culture models, which allow for easy cell manipulation. It has become clear that intracellular signaling pathways are affected by extracellular forces, including dimensionality and cell surface tension(3-4). Multiple approaches have been taken to develop three-dimensional models that more accurately represent biologic tissue architecture(3). While these models incorporate multi-dimensionality and architectural stresses, study of the consequent effects on cells is less facile than in two-dimensional tissue culture due to the limitations of the models and the difficulty in extracting cells for subsequent analysis. The important role of the microenvironment around tumors in tumorigenesis and tumor behavior is becoming increasingly recognized(4). Tumor stroma is composed of multiple cell types and extracellular molecules. During tumor development there are bidirectional signals between tumor cells and stromal cells(5). Although some factors participating in tumor-stroma co-evolution have been identified, there is still a need to develop simple techniques to systematically identify and study the full array of these signals(6). Fibroblasts are the most abundant cell type in normal or tumor-associated stromal tissues, and contribute to deposition and maintenance of basement membrane and paracrine growth factors(7). Many groups have used three dimensional culture systems to study the role of fibroblasts on various cellular functions, including tumor response to therapies, recruitment of immune cells, signaling molecules, proliferation, apoptosis, angiogenesis, and invasion(8-15). We have optimized a simple method for assessing the effects of mammary fibroblasts on mammary epithelial cells using a commercially available extracellular matrix model to create three-dimensional cultures of mixed cell populations (co-cultures)(16-22). With continued co-culture the cells form spheroids with the fibroblasts clustering in the interior and the epithelial cells largely on the exterior of the spheroids and forming multi-cellular projections into the matrix. Manipulation of the fibroblasts that leads to altered epithelial cell invasiveness can be readily quantified by changes in numbers and length of epithelial projections(23). Furthermore, we have devised a method for isolating epithelial cells out of three-dimensional co-culture that facilitates analysis of the effects of fibroblast exposure on epithelial behavior. We have found that the effects of co-culture persist for weeks after epithelial cell isolation, permitting ample time to perform multiple assays. This method is adaptable to cells of varying malignant potential and requires no specialized equipment. This technique allows for rapid evaluation of in vitro cell models under multiple conditions, and the corresponding results can be compared to in vivo animal tissue models as well as human tissue samples.

Intravesical gemcitabine for non-muscle invasive bladder cancer

BACKGROUND

Intravesical immunotherapy or chemotherapy for non-muscle invasive bladder cancer is a well established treatment for preventing or delaying tumour recurrence following tumour resection. However, up to 70% of patients may fail and new intravesical agents with improved effectiveness are needed. Gemcitabine is a relatively new anticancer drug that has shown activity against bladder cancer.

OBJECTIVES

To evaluate the effectiveness and toxicity of intravesical gemcitabine in preventing tumour recurrence and progression in non-muscle invasive bladder cancer (NMIBC).

SEARCH METHODS

A search strategy was developed for MEDLINE to identify randomised trials of intravesical gemcitabine for the treatment of non-muscle invasive bladder cancer. The searches were from 1947 to May 2011. Other databases searched included EMBASE, CINAHL, the Cochrane Central Register of Controlled Trials, LILACS, SCOPUS, BNI, Biomed Central, Web of Science and BIOSIS. Handsearching of meeting proceedings, international guidelines and trial registries was also carried out.

SELECTION CRITERIA

The titles and abstracts of the combined electronic and handsearching were manually screened by three authors independently to determine if they met the inclusion criteria for this review. Studies were selected if they were randomised, controlled trials or quasi-randomised clinical trials that included intravesical gemcitabine in at least one arm of a comparative study.

DATA COLLECTION AND ANALYSIS

Data extraction was carried out by three reviewers. The information retrieved included the author's details, the study design, the characteristics of the recruited patients, details of the interventions and data relating to the primary, and secondary outcome measures.

MAIN RESULTS

Six relevant randomised trials were identified with the number of patients randomised in each trial varying from 30 to 341 (total 704). All trials compared gemcitabine to active controls and varied in the reporting of outcomes. One study compared a single post-operative instillation of intravesical gemcitabine with a saline placebo in 341 patients and found no significant difference in the rates of tumour recurrence (28% versus 39%, respectively) or recurrence-free survival (HR (hazard ratio) 0.95, 95% CI 0.64 to1.39, P = 0.77). The rate of progression to invasive disease was greater with gemcitabine (2.4% versus 0.8%). A further trial compared gemcitabine with intravesical mitomycin C and demonstrated that the rates of recurrence (28% versus 39%) and progression (11% versus 18%) were lower with gemcitabine but did not reach statistical significance. The global incidence of adverse events was significantly less with gemcitabine (38.8% versus 72.2%, P = 0.02).Three trials compared gemcitabine with intravesical BCG but a meta-analysis was not possible due to clinical heterogeneity. In untreated patients at intermediate risk of recurrence (primary Ta-T1 no CIS) one trial showed that gemcitabine and BCG were similar with respective recurrence rates of 25% and 30% (P = 0.92) and overall progression equal (P = 1.0). Dysuria (12.5% versus 45%, P < 0.05) and frequency (10% versus 45%, P < 0.001) were significantly less with gemcitabine. In a second trial of high risk patients the recurrence rate was significantly greater with gemcitabine compared to BCG (53.1% and 28.1%, P = 0.04) and the time to recurrence significantly shorter with gemcitabine (25.5 versus 39.4 months, P = 0.042). Finally in a third trial of high risk patients who had failed previous intravesical BCG therapy, gemcitabine was associated with significantly fewer recurrences (52.5% versus 87.5%, P = 0.002) and a longer time to recurrence (3.9 versus 3.1 months, P = 0.9) compared to BCG. Progression rates were similar in both groups (33% versus 37.5%, P = 0.12) with no significant differences in grade 2 or 3 toxicities.The final trial was a marker lesion study which reported greater response rates when intravesical gemcitabine (2 g) was given as three bi-weekly doses (36%) or six weekly doses (40%) compared to a single dose (9%).

AUTHORS' CONCLUSIONS

A single dose immediately following surgery is ineffective based on one study. Gemcitabine may be more active than mitomycin C with a lower toxicity profile. Compared to intravesical BCG therapy, gemcitabine had similar effects in intermediate risk patients, less effective in high risk patient and superior in BCG refractory patients. However, each randomised trial identified represents a different clinical setting in NMIBC and therefore the evidence base is limited. Consequently these data should be interpreted with caution until further corroborative evidence becomes available. The aim of intravesical therapy in NMIBC is to prevent tumour recurrence and progression and to avoid the morbidity associated with cystectomy. Intravesical gemcitabine is a promising drug that may add to the urologist's options in achieving this goal.

Everolimus enhances gemcitabine-induced cytotoxicity in bladder-cancer cell lines

The purpose of this study was to determine whether everolimus, a rapamycin derivative, might significantly enhance the cytotoxicity of gemcitabine, an antitumor drug, in two human bladder-cancer cell lines. Human bladder-cancer T24 and 5637 cells were incubated with gemcitabine and everolimus in a range of concentrations either alone or in combination for 72 h. Flow cytometry, comet assay, MTT method and optical microscopy were used to assess cell proliferation, cell cycle, DNA damage, and morphological alterations. Gemcitabine exerted an inhibitory effect on T24 and 5637 cell proliferation, in a concentration-dependent manner. Everolimus significantly reduced proliferation of 5637 bladder cancer cells (IC₃₀) at 1 μM), whereas T24 demonstrated marked resistance to everolimus treatment. A significant antiproliferative effect was obtained combining gemcitabine (100 nM) with everolimus (0.05-2 μM) with an arrest of cell cycle at S phase. Furthermore, an increase in frequency of DNA damage, apoptotic bodies, and apoptotic cells was observed when T24 and 5637 cancer cells were treated simultaneously with both drugs. Data show that in vitro combination produced a more potent antiproliferative effect when compared with single drugs.

Management of BCG non-responders with fixed dose intravesical gemcitabine in superficial transitional cell carcinoma of urinary bladder

Aims and Objectives:

The incidence of bladder malignancy is increasing worldwide and the projected rise is 28% by 2010 for both sexes (WHO). Though intravesical adjuvant therapy with BCG is superior to any other immunotherapeutic/chemotherapeutic agent in reducing tumor recurrences and disease progression, its real efficacy remains controversial as one-third of the patients will soon become BCG failure. Hence there is a need for an alternative intravesical agent for treatment of BCG failure. Our aim was to study the efficacy, tolerability and safety of intravesical Gemcitabine in managing BCG-refractory superficial bladder malignancy.

Materials and Methods:

Thirty-five BCG failure patients, 26 males and nine females between 20-72 years of age were instilled with 2000 mg of Gemcitabine in 50 ml of normal saline intravesically two weeks post tumor resection, for six consecutive weeks. Mean follow-up was for 18 months with cystoscopies.

Results:

Twenty-one patients (60%) showed no recurrences, 11 patients (31.4%) had superficial recurrences while three patients (8.6%) progressed to muscle invasiveness. Average time to first recurrence was 12 months and to disease progression was 16 months. Adverse event was low and mild. Therapy was well tolerated.

Conclusion:

Gemcitabine fulfils all requirements as an alternative agent, in treating BCG failure patients with low adverse events, is well tolerated and highly effective in reducing tumor recurrences.

Intravesicle gemcitabine in management of BCG refractory superficial TCC of urinary bladder-our experience

INTRODUCTION

The incidence of bladder malignancy is increasing worldwide and the projected rise is 28% by 2010 for both sexes (according to the WHO). Though intravesical adjuvant therapy with bacillus Calmette-Guérin (BCG) is superior to any other immunotherapeutic/chemotherapeutic agent in reducing tumor recurrences and disease progression, its real efficacy remains controversial as one-third of the patients will soon develop BCG failure. Hence, there is a need for an alternative intravesical agent for treatment of BCG failure. Our aim is to study the efficacy, tolerability, and safety of intravesical gemcitabine in managing BCG refractory superficial bladder malignancy.

MATERIAL AND METHODS

Thirty-five BCG failure patients, 26 males and 9 females between 20 and 72 years of age were instilled 2000 mg of gemcitabine in 50 ml of normal saline intravesically 2 weeks post-tumor resection, for 6 consecutive weeks. Mean follow-up for 18 months with cystoscopy was done.

RESULT

Twenty-one patients (60%) showed no recurrences, 11 patients (31.4%) had superficial recurrences, while 3 patients (8.75%) progressed to muscle invasiveness. Average time to first recurrence was 12 months and to disease progression was 16 months. Adverse event was low and mild. Therapy was well tolerated.

CONCLUSION

Gemcitabine fulfills all requirements as an alternative agent in treating BCG failure patients with low adverse events, well tolerated, and highly effective in reducing tumor recurrences.

Intravesical gemcitabine: an update of clinical results

PURPOSE OF REVIEW

Nonmuscle-invasive bladder cancer is a common malignancy, standardly treated by transurethral resection and adjuvant intravesical instillations of chemotherapy or immunotherapy. Adjuvant instillations are needed to reduce recurrence and/or progression. With currently existing adjuvant treatments, however, recurrences still occur, progression is hardly influenced and these treatments induce local or systemic side effects. In search for efficacy improvement and side effect reduction, we reviewed the promising properties of the relatively new intravesical drug, gemcitabine.

RECENT FINDINGS

The safety of gemcitabine is tested in different instillation schemes, drug concentrations and administered volumes. Its safety profile is excellent, with good tolerability and minimal toxicity up to 2000 mg/50 ml for 2-h instillations. In comparison with other drugs, the ablative efficacy of gemcitabine is good. The first studies on prophylactic efficacy in intermediate-risk, high-risk and bacillus Calmette-Guerin-refractory patients are promising but limited by the small number of patients studied.

SUMMARY

The available literature underlines the promising properties of gemcitabine for the intravesical use against nonmuscle-invasive bladder cancer. Exploring phase-II and comparative randomized phase-III studies should provide additional information on gemcitabine and its benefit to clinical practice.

Intravesical mitomycin C for superficial transitional cell carcinoma

Intravesical instillation of mitomycin C after a transurethral resection of a bladder tumor constitutes a standard treatment modality in the management of superficial transitional cell carcinoma in the urinary bladder. An immediate instillation of mitomycin C after transurethral resection has been shown to reduce the recurrence rate of superficial transitional cell carcinoma. Intravesical mitomycin C is generally considered to be a safe treatment option, but the past few years have seen the publication of a number of case reports on severe complications following mitomycin C instillation. This article reports on the mode of action, as well as the intravesical effects and current indications for mitomycin C instillation. This review will summarize the oncological benefits of mitomycin C in comparison with other intravesical treatments, such as bacillus Calmette-Guérin, and elucidate the incidence and types of possible complications associated with intravesical mitomycin C chemotherapy.

Short-schedule intravesical gemcitabine with ablative intent in recurrent Ta-T1, G1-G2, low- or intermediate-risk, transitional cell carcinoma of the bladder

OBJECTIVES

PRIMARY OBJECTIVE

to assess ablative efficacy and tolerability of short-schedule intravesical gemcitabine for intact, low- and intermediate-risk, recurrent superficial bladder tumours.

SECONDARY OBJECTIVE

to assess effect on prophylaxis.

METHODS

Patients with a diagnosis of recurrence and a history of previous superficial, low- or intermediate-risk bladder tumours were selected for the study. They received 2000 mg gemcitabine in 50 ml, that is 40 mg/ml, intravesically, weekly for 4 wk, followed by resection of any residual lesions. Complete responses consisted of absence of any macroscopic, histologically confirmed, residual lesion, and no response in the presence of residual lesions. The effect on prophylaxis was measured in months as disease-free interval to first recurrence, and as percentage of patients recurring within the first 12 mo. Toxicity was assessed as local and systemic.

RESULTS

Of 34 recruited patients, 28 consecutive patients were evaluable, with complete responses observed in 13 of 28 (46.4%) and no response in 15 (53.6%). Median time to first recurrence was 9.1 mo (range: 2.9-26.5) for 19 of 28 (67.8%) patients experiencing recurrence during the first year. Local or systemic toxicity was observed in 9 of 34 (26.4%) patients, resulting in protocol interruption in 6 patients.

CONCLUSIONS

Intravesical gemcitabine alone showed ablative efficacy in nearly one half of the patients under study. Drug tolerability was good, both locally and systemically.

Gemcitabine in intravesical treatment of Ta-T1 transitional cell carcinoma of bladder: Phase I-II study on marker lesions

OBJECTIVES

To study the ablative activity of intravesical gemcitabine against superficial transitional cell carcinoma of the bladder at different doses and concentrations.

METHODS

A total of 27 patients were treated with intravesical gemcitabine after transurethral resection during which one to three papillary marker lesions were left unresected. Starting 14 days after transurethral resection, six instillations of gemcitabine were given at weekly intervals. Gemcitabine, diluted in 50 mL of saline solution and maintained for 2 hours, was given at the dose of 500 mg, 1000 mg, and 2000 mg in groups of 9 patients each. A complete response (CR) was defined as negative cytology, cystoscopy, and biopsy findings. Patients achieving a CR received monthly maintenance for up to 1 year and underwent cytology and cystoscopy at 3-month intervals.

RESULTS

Of the 27 patients, 1 was lost to follow-up, and of the remaining 26 patients, 6 (23%) achieved a CR. A CR was achieved in 1 patient (12.5%), 2 patients (22.2%), and 3 patients (33.3%) at a dose of 500, 1000, and 2000 mg, respectively. A partial response was obtained in 2 additional patients (22%) at a dose of 500 and 1000 mg. Bladder Tis was diagnosed in 2 patients with a CR at 3 and 8 months after treatment. The remaining 4 patients were disease free at a follow-up of up to 22 months. Systemic and local tolerability was excellent, and no treatment interruption was required.

CONCLUSIONS

Our experience has shown the good tolerability and potential efficacy of intravesical gemcitabine against recurrent transitional cell carcinoma of the bladder. Gemcitabine might be proposed, if our results are confirmed by larger studies, as a second-line therapy in patients who cannot tolerate more aggressive intravesical therapy.

Schedule-dependent cytotoxic interaction between epidoxorubicin and gemcitabine in human bladder cancer cells in vitro

PURPOSE

The aim of the study was to evaluate the activity of epidoxorubicin (EPI) and gemcitabine (GEM) and to define the most effective schedule in human bladder cancer cells.

EXPERIMENTAL DESIGN

The study was performed on HT1376 and MCR cell lines. Cells were exposed for 1 and 24 h to drugs used in different schemes. Cytotoxic activity was evaluated by the sulforhodamine B assay, potential clinical activity was estimated by relative antitumor activity, and the type of drug interaction was assessed using the method of Chou and Talalay. Cell cycle perturbations and apoptosis were assessed by flow cytometry; BAX, BCL-2, and P53 expression was evaluated by Western blot; and DNA damage was assessed using the alkaline Comet assay.

RESULTS

EPI and GEM produced a cytotoxic effect in both cell lines, with 50% inhibitory concentration and relative antitumor activity values suggestive of a high clinical activity. Simultaneous treatment with EPI and GEM and the sequence GEM-->EPI caused an antagonistic interaction (combination index > 1) after both 1- and 24-h treatments. Conversely, the inverse sequence, EPI-->GEM, produced a synergistic interaction that was more pronounced in MCR cells than in HT1376 cells. The increase in DNA-damaged cells from 10% to 20% after single-drug exposure to 40-60% at the end of EPI-->GEM treatment may explain the synergistic interaction produced by the anthracycline-antimetabolite sequence.

CONCLUSIONS

Our findings show that the efficacy of the EPI and GEM combination is highly schedule dependent and indicate that the most active scheme is EPI followed by GEM, which is currently being validated in an ongoing intravesical Phase I-II clinical protocol.

Phase II Study to Investigate the Ablative Efficacy of Intravesical Administration of Gemcitabine in Intermediate-Risk Superficial Bladder Cancer (SBC)

OBJECTIVE

Phase I studies have so far demonstrated that intravesical Gemcitabine up to a 40 mg/ml concentration is well tolerated and has a substantial ablative activity on high-risk BCG refractory SBC. New treatment options are needed for intermediate-risk SBC recurring after conventional intravesical treatments. The purpose of the present study was to investigate the ablative efficacy of intravesical Gemcitabine on intermediate-risk SBC.

METHODS

The study was designed as a two-stage phase II trial, with a sample size of 39 patients. The efficacy of intravesical Gemcitabine at a concentration of 40 mg/ml (2000 mg in 50 ml saline solution) administered weekly for 6 weeks was assessed on a single marker tumour left in the bladder after a complete TUR of all other lesions. Patients underwent TUR or biopsy at the site of the marker lesion 2 weeks after completion of the treatment.

RESULTS

Complete response was observed in 22 out of 39 patients (56%). No progression was observed among the 17 non-responders. Neither systemic nor local side effects generally exceeded grade I toxicity.

CONCLUSION

The ablative effect of Gemcitabine produced a higher number of responses than the minimum required by the protocol to indicate a significant probability of drug efficacy. It is worth testing the drug in phase III trials to assess for durability of response.

The current status of intravesical therapy for superficial bladder cancer

PURPOSE OF REVIEW

To analyse recent advances in intravesical instillation therapy for superficial bladder cancer.

RECENT FINDINGS

Although intravesical bacillus Calmette-Guérin has been used for many years in the treatment of superficial bladder cancer, its mechanism of action remains unclear, its poor tolerance remains a problem, the prediction of its efficacy has still to be validated, and its long-term effects on progression and survival are controversial. The exact timing and place of intravesical chemotherapy needs to be better defined, as well as the place of some new molecules. Finally, new approaches need to be explored for overcoming the limitations of the usual intravesical agents.

SUMMARY

No dramatic advances have been made in understanding the mechanisms of action of bacillus Calmette-Guérin during the past year. However, a careful dissection of this complex immunological pathway continues and immunological criteria are promising for predicting the response to bacillus Calmette-Guérin. Evidence has been accumulating to suggest that a dose reduction during the initial treatment remains effective and reduces side-effects. In addition, bacillus Calmette-Guérin maintenance therapy is useful for high-risk patients. However, long-term tolerance remains an important issue, and the optimal protocol has not yet been defined. On the other hand, it has been proved that intravesical chemotherapy, when administered early after transurethral resection, is effective in preventing frequent recurrences, whereas maintenance chemotherapy is ineffective. Finally, new approaches, including instillations of activated immune cells or targeted gene therapy, are being explored.

Five new cassane diterpenes from Myrospermum frutescens with activity against Trypanosoma cruzi

Five novel cassane diterpenes (1-5) with activity against Trypanosoma cruzi were isolated from leaves of Myrospermum frutescens. The structures were determined as 18-hydroxycassan-13,15-diene (1), 6beta,18-dihydroxycassan-13,15-diene (2), 6beta-hydroxy-18-acetoxycassan-13,15-diene (3), 18-acetoxy-13,15-diene-19-cassanoic acid (4), and 6beta,13beta-dihydroxy-18-acetoxycassan-14(17),15-diene (5). Structures were elucidated by spectroscopic analysis (NMR and HRCIMS) and by the synthesis of derivatives 2a and 2b. Compounds 3 and 5 were more active against the extracellular form of the parasite (11 and 16 microM, respectively) than the intracellular forms, while compounds 1 and 2 were more active against the more clinically relevant intracellular forms of the parasite (17 microM). Compounds 1 and 2 were approximately 9-fold more toxic toward T. cruzi than toward human fibroblasts, the cell type that serves as the parasite's mammalian host cell.

Selective reovirus killing of bladder cancer in a co-culture spheroid model

Up to 50% of the transitional cell carcinomas (TCC) express an activated EGF pathway involving MAP/MEK and RAF kinase thus providing a novel means to selectively eliminate transformed cells expressing such proteins. This EGF pathway expression phenotype was also confirmed in our MGH-U3 and room temperature-112 human TCC cell lines, which makes them a suitable model target for the reovirus oncolysis. We report here on an in vitro assay of co-culture spheroids using either human or rat TCC cells with their corresponding fibroblasts to examine the potential of viral selective lysis for TCC. Reovirus, a respiratory enteric orphan virus, which mammals are exposed to early in life, was used in this study. Selective killing of transformed versus normal cells was assayed by time-lapse photography, vital dye staining, immunohistochemistry, and MTT assay. In this in vitro bladder cancer model, reovirus selectively destroyed the transformed cells by lysis or induction of apoptosis. Based on these findings we have initiated an in vivo pre-clinical study on intravesical administration of reovirus in an animal model to further explore the effect of reovirus-mediated oncolysis of TCC.