Quinolone antibiotics: a potential adjunct to intravesical chemotherapy for bladder cancer

Host-pathogen interaction: Enterobacter cloacae exerts different adhesion and invasion capacities against different host cell types

New antibiotics are urgently needed due to the huge increase of multidrug-resistant bacteria. The underexplored gram-negative bacterium Enterobacter cloacae is known to cause severe urinary tract and lung infections (UTIs). The pathogenicity of E. cloacae in UTI has only been studied at the bioinformatic level, but until now not within systematic in vitro investigations. The present study assesses different human cell lines for monitoring the early steps of host-pathogen interaction regarding bacterial adhesion to and invasion into different host cells by flow cytometric adhesion assay, classical cell counting assay, gentamicin invasion assay, and confocal laser scanning microscopy. To our knowledge, this is the first report in which E. cloacae has been investigated for its interaction with human bladder, kidney, skin, and lung cell lines under in vitro conditions. Data indicate that E. cloacae exerts strong adhesion to urinary tract (bladder and kidney) and lung cells, a finding which correlates with the clinical relevance of the bacterium for induction of urinary tract and lung infections. Furthermore, E. cloacae ATCC 13047 barely adheres to skin cells (A-431) and shows no relevant interaction with intestinal cells (Caco-2, HT-29), even in the presence of mucin (HT29 MTX). In contrast, invasion assays and confocal laser scanning microscopy demonstrate that E. cloacae internalizes in all tested host cells, but to a different extent. Especially, bladder and kidney cells are being invaded to the highest extent. Defective mutants of fimH and fimA abolished the adhesion of E. cloacae to T24 cells, while csgA deletion had no influence on adhesion. These results indicate that E. cloacae has different pattern for adhesion and invasion depending on the target tissue, which again correlates with the clinical relevance of the pathogen. For detailed investigation of the early host-pathogen interaction T24 bladder cells comprise a suitable assay system for evaluation the bacterial adhesion and invasion.

Effect of four fluoroquinolones on the viability of bladder cancer cells in 2D and 3D cultures

Introduction

The anticancer properties of fluoroquinolones and the high concentrations they achieve in urine may help in bladder cancer therapy. This study aimed to analyze the properties of 4 fluoroquinolones as potential candidates for supportive treatment of bladder cancer.

Methods

Comparative analyses were performed on the cytotoxic effects of norfloxacin, enrofloxacin, moxifloxacin, and ofloxacin on normal and cancer urothelial cell lines. In 2D culture, the cytotoxic properties of fluoroquinolones were evaluated using MTT assay, real-time cell growth analysis, fluorescence and light microscopy, flow cytometry, and molecular analysis. In 3D culture, the properties of fluoroquinolones were tested using luminescence assays and confocal microscopy.

Results and Discussion

All tested fluoroquinolones in 2D culture decreased the viability of both tested cell lines in a dose- and timedependent manner. Lower concentrations did not influence cell morphology and cytoskeletal organization. In higher concentrations, destruction of the actin cytoskeleton and shrinkage of the nucleus was visible. Flow cytometry analysis showed cell cycle inhibition of bladder cancer cell lines in the G2/M phase. This influence was minimal in the case of normal urothelium cells. In both tested cell lines, increases in the number of late apoptotic cells were observed. Molecular analysis showed variable expression of studied genes depending on the drug and concentration. In 3D culture, tested drugs were effective only in the highest tested concentrations which was accompanied by caspase 3/7 activation and cytoskeleton degradation. This effect was hardly visible in non-cancer cell lines. According to the data, norfloxacin and enrofloxacin had the most promising properties. These two fluoroquinolones exhibited the highest cytotoxic properties against both tested cell lines. In the case of norfloxacin, almost all calculated LC values for bladder cancer cell lines were achievable in the urine. Enrofloxacin and norfloxacin can be used to support chemotherapy in bladder cancer patients.

Influence of Antibiotic Administration on the Urinary Bladder Cancer Early Recurrence Rate

Bladder cancer tends to recur, making treatment one of the most expensive in oncology. The limited efficacy and high cost of adjuvant therapies in the treatment of bladder cancer prompt research on new drugs which could replace them. In vitro studies have established that antibiotics can have a cytostatic and cytotoxic effect on urinary bladder cancer cells. The objective of the study was to investigate the influence of antibiotics on the recurrence rate of bladder cancer. In a retrospective study, we analyzed a group of 199 patients with urinary bladder cancer from four urological centers. The study groups consisted of 40 patients who received ciprofloxacin and 83 patients who received beta-lactams as perioperative antimicrobial prophylaxis. The control group included 76 patients who did not get perioperative antimicrobial prophylaxis. The groups were analyzed for risk stratification, degree of malignancy, and size of the primary tumor. The average follow-up time was 24 months. The main focus of the study was to investigate the early recurrence rate of bladder cancer among studied groups, which could correlate with the effectiveness of currently used intravesical instillations. Additionally, cancer’s early progression was examined. Regardless of the division used, the highest recurrence rate was found in the ciprofloxacin group. There were no statistical differences in the recurrence rate between patients who received beta-lactams and patients who did not receive any antibiotics. In addition, there were no differences due to the progression rate between the groups. Perioperative antibiotic administration does not influence the early recurrence rate in patients with nonmuscle invasive urothelial bladder cancer.

Quinolones as a Potential Drug in Genitourinary Cancer Treatment-A Literature Review

Quinolones, broad-spectrum antibiotics, are frequently prescribed by urologists for many urological disorders. The mechanism of their bactericidal activity is based on the inhibition of topoisomerase II or IV complex with DNA, which consequently leads to cell death. It has been observed that these antibiotics also act against the analogous enzymes present in eukaryotic cells. Due to their higher accumulation in urine and prostate tissue than in serum, these drugs seem to be ideal candidates for application in genitourinary cancer treatment. In this study, an extensive literature review has been performed to collect information about concentrations achievable in urine and prostate tissue together with information about anticancer properties of 15 quinolones. Special attention was paid to the application of cytotoxic properties of quinolones for bladder and prostate cancer cell lines. Data available in the literature showed promising properties of quinolones, especially in the case of urinary bladder cancer treatment. In the case of prostate cancer, due to low concentrations of quinolones achievable in prostate tissue, combination therapy with other chemotherapeutics or another method of drug administration is necessary.

Ciprofloxacin and Levofloxacin as Potential Drugs in Genitourinary Cancer Treatment-The Effect of Dose-Response on 2D and 3D Cell Cultures

Introduction: Introducing new drugs for clinical application is a very difficult, long, drawn-out, and costly process, which is why drug repositioning is increasingly gaining in importance. The aim of this study was to analyze the cytotoxic properties of ciprofloxacin and levofloxacin on bladder and prostate cell lines in vitro. Methods: Bladder and prostate cancer cell lines together with their non-malignant counterparts were used in this study. In order to evaluate the cytotoxic effect of both drugs on tested cell lines, MTT assay, real-time cell growth analysis, apoptosis detection, cell cycle changes, molecular analysis, and 3D cultures were examined. Results: Both fluoroquinolones exhibited a toxic effect on all of the tested cell lines. In the case of non-malignant cell lines, the cytotoxic effect was weaker, which was especially pronounced in the bladder cell line. A comparison of both fluoroquinolones showed the advantage of ciprofloxacin (lower doses of drug caused a stronger cytotoxic effect). Both fluoroquinolones led to an increase in late apoptotic cells and an inhibition of cell cycle mainly in the S phase. Molecular analysis showed changes in BAX, BCL2, TP53, and CDKN1 expression in tested cell lines following incubation with ciprofloxacin and levofloxacin. The downregulation of topoisomerase II genes (TOP2A and TOP2B) was noticed. Three-dimensional (3D) cell culture analysis confirmed the higher cytotoxic effect of tested fluoroquinolone against cancer cell lines. Conclusions: Our results suggest that both ciprofloxacin and levofloxacin may have great potential, especially in the supportive therapy of bladder cancer treatment. Taking into account the low costs of such therapy, fluoroquinolones seem to be ideal candidates for repositioning into bladder cancer therapeutics.

Clinical Perspective of FDA Approved Drugs With P-Glycoprotein Inhibition Activities for Potential Cancer Therapeutics

P-glycoprotein (also known as multidrug resistance protein 1 (MDR1) or ATP-binding cassette sub-family B member 1 (ABCB1) plays a crucial role in determining response against medications, including cancer therapeutics. It is now well established that p-glycoprotein acts as an ATP dependent pump that pumps out small molecules from cells. Ample evidence exist that show p-glycoprotein expression levels correlate with drug efficacy, which suggests the rationale for developing p-glycoprotein inhibitors for treatment against cancer. Preclinical and clinical studies have investigated this possibility, but mostly were limited by substantial toxicities. Repurposing FDA-approved drugs that have p-glycoprotein inhibition activities is therefore a potential alternative approach. In this review, we searched the Drugbank Database (https://www.drugbank.ca/drugs) and identified 98 FDA-approved small molecules that possess p-glycoprotein inhibition properties. Focusing on the small molecules approved with indications against non-cancer diseases, we query the scientific literature for studies that specifically investigate these therapeutics as cancer treatment. In light of this analysis, potential development opportunities will then be thoroughly investigated for future efforts in repositioning of non-cancer p-glycoprotein inhibitors in single use or in combination therapy for clinical oncology treatment.

Repositioning of fluoroquinolones from antibiotic to anti-cancer agents: An underestimated truth

Increasing development costs and higher failure rate in clinical trials has reduced the repertoire of newer drugs in the market for clinical use. The most appropriate approach to end the search for newer drugs is "Repositioning", as it requires less time and money to explore new indication of existing drug or failed drug. In the past, several drugs have been repositioned for different indication but the full potential remains unharnessed. With rise in cancer prevalence and treatment costs, it is imperative to search for newer drugs and the use of repositioning approach may help us. Fluoroquinolones has been used as antibiotics for over four decades now, but recent research highlighted their use as pharmacological compounds with multifaceted implication. Repositioning of fluoroquinolones into anti-cancer molecule seems to be a highly plausible option owing to their profound immunomodulatory, pro-apoptotic, anti-proliferative and anti-metastatic potential. The present review provides a comprehensive account of the recent and past explorations pertaining to the anti-cancer activity of fluoroquinolones and also discusses the various approaches that are being considered to remodel them for the treatment of cancer.

Intercalation of a Zn(II) complex containing ciprofloxacin drug between DNA base pairs

In this study, an attempt has been made to study the interaction of a Zn(II) complex containing an antibiotic drug, ciprofloxacin, with calf thymus DNA using spectroscopic methods. It was found that Zn(II) complex could bind with DNA via intercalation mode as evidenced by: hyperchromism in UV-Vis spectrum; these spectral characteristics suggest that the Zn(II) complex interacts with DNA most likely through a mode that involves a stacking interaction between the aromatic chromophore and the base pairs of DNA. DNA binding constant (K_b = 1.4 × 10⁴ M^-1) from spectrophotometric studies of the interaction of Zn(II) complex with DNA is comparable to those of some DNA intercalative polypyridyl Ru(II) complexes 1.0 -4.8 × 10⁴ M^-1. CD study showed stabilization of the right-handed B form of DNA in the presence of Zn(II) complex as observed for the classical intercalator methylene blue. Thermodynamic parameters (ΔH < 0 and ΔS < 0) indicated that hydrogen bond and Van der Waals play main roles in this binding prose. Competitive fluorimetric studies with methylene blue (MB) dye have shown that Zn(II) complex exhibits the ability of this complex to displace with DNA-MB, indicating that it binds to DNA in strong competition with MB for the intercalation.

Synthesis of novel tetrazole containing hybrid ciprofloxacin and pipemidic acid analogues and preliminary biological evaluation of their antibacterial and antiproliferative activity

A series of 1-substituted-1H-tetrazole-5-thiol building blocks were synthesized and introduced to the N-4 piperazinyl group at C-7 position of the quinolone core, and these novel compounds (5a-g and 8a-g) were screened for their antibacterial and antiproliferative activities. Bioactive assay studies manifested that most of new compounds exhibited significant antibacterial activity against the tested strains, including multi-drug-resistant MRSA in comparison with reference drugs ciprofloxacin, streptomycin B and pipemidic acid. Among the synthesized compounds, only ciprofloxacin (5a-g) derivatives displayed significant activity ([Formula: see text]) compared to reference drugs. In addition, these compounds were evaluated for their in vitro inhibition of human cancer cell lines viz human cervical carcinoma cell line (SiHA), breast adenocarcinoma (MDA-MB-235) and human pancreas carcinoma (PANC-1) cell lines by using the SRB assay method. Most of the target compounds showed broad potent growth inhibition activity ([Formula: see text]) against all the tested cancer cell lines compared with reference drug. The most promising active compounds in this series were 5c, 5d, 8c, 8d and 8f endowed with excellent antiproliferative activity. A new class of compounds was designed rationally by introducing tetrazole building block on N-4 piperazinyl group at C-7 position of quinolones core. The titled compounds were evaluated for their preliminary antibacterial and antiproliferative activities.

Synthesis of novel ethyl 1-ethyl-6-fluoro-7-(fatty amido)-1,4-dihydro-4-oxoquinoline-3-carboxylate derivatives and their biological evaluation

A series of novel ethyl 1-ethyl-6-fluoro-7-(fatty amido)-1,4-dihydro-4-oxoquinoline-3-carboxylate derivatives were prepared through multistep synthesis. The key step in the synthesis was to obtain the C-7 fatty amide derivative. The azide was selectively formed at C-7 position using sodium azide at 60°C. Subsequently, the azide was reduced under mild conditions using zinc and ammonium chloride to form the corresponding amine. The synthesized derivatives were further subjected to biological evaluation studies like cytotoxicity against a panel of cancer cell lines such as DU145, A549, SKOV3, MCF7 and normal lung cells, IMR-90 as well as with antimicrobial and antioxidant activities. It was observed that the carboxylated quinolone derivatives with hexanoic (8a), octanoic (8b), lauric (8d) and myristic (8e) moieties exhibited promising cytotoxicity against all the tested cancer cell lines. The results also suggested that hexanoic acid-based fatty amide carboxylated quinolone derivative (8a) exhibited promising activity against both bacterial and fungal strains and significant antibacterial activity was observed against Staphylococcus aureus MTCC 96 (MIC value of 3.9μg/mL). The compound 8a also showed excellent anti-biofilm activity against Staphylococcus aureus MTCC 96 and Bacillus subtilis MTCC 121 with MIC values of 2.1 and 4.6μg/mL, respectively.

Using antimicrobial adjuvant therapy in cancer treatment: a review

Recent clinical and pre-clinical data demonstrate that adjuvant antimicrobial therapy is beneficial in cancer treatment. There could be several reasons for this effect, which include treating cancer associated bacteria and viruses, prophylaxis of post-chemotherapy infections due to immunosuppression, and antiproliferative effect of certain antimicrobials. Targeting cancer associated viruses and bacteria with antimicrobial agents is currently used for gastric, cervical, hematopoietic, liver and brain cancer. However this treatment is effective only in combination with conventional therapies. Antimicrobials can also have a direct antiproliferative and cytotoxic effect, and can cause apoptosis. Moreover, some antimicrobials are known to be helpful in overcoming side effects of drugs commonly used in cancer treatment. Chemotherapy related bacteremia and neutropenia can be overcome by the appropriately timed use of antimicrobials. This review summarizes the data on the effects of antivirals and antibiotics on cancer treatment and describes their mechanisms.

Piperonal ciprofloxacin hydrazone induces growth arrest and apoptosis of human hepatocarcinoma SMMC-7721 cells

AIM

To investigate the cytotoxic effects of piperonal ciprofloxacin hydrazone (QNT4), a novel antibacterial fluoroquinolone derivative, against human hepatocarcinoma SMMC-7721 cells.

METHODS

Human hepatocarcinoma cells (SMMC-7721), human breast adenocarcinoma cells (MCF-7) and human colon adenocarcinoma cells (HCT-8) were tested. The effects of QNT4 on cell proliferation were examined using MTT assay. Cell apoptosis was determined using Hoechst 33258 fluorescence staining, TUNEL assay and agarose gel electrophoresis. The topoisomerase II activity was measured using agarose gel electrophoresis with the DNA plasmid pBR322 as the substrate. Mitochondrial membrane potential (Δψm) was measured using a high content screening imaging system. Protein expression of caspase-9, caspase-8, caspase-3, p53, Bcl-2, Bax, and cytochrome c was detected with Western blot analysis.

RESULTS

Treatment with QNT4 (0.625-10 μmol/L) potently inhibited the proliferation of the cancer cells in time- and dose-dependent manners (the IC(50) value at 24 h in SMMC-7721 cells, MCF-7 cells and HCT-8 cells was 2.956±0.024, 3.710±0.027, and 3.694±0.030 μmol/L, respectively). Treatment of SMMC-7721 cells with QNT4 (0.2146, 2.964, and 4.600 μmol/L) for 24 h dose-dependently increased the percentage of apoptotic cells, elicited characteristic DNA "ladder" bands, and decreased the mitochondrial membrane potential. QNT4 dose-dependently increased topoisomerase II-mediated DNA breaks while inhibiting DNA relegation, thus keeping the DNA in fragments. Treatment of SMMC-7721 cells with QNT4 significantly increased cytochrome c in the cytosol, and decreased cytochrome c in the mitochondrial compartment. QNT4 (3-7.39 μmol/L) significantly increased the protein expression of p53, Bax, caspase-9, caspase-3, and the cleaved activated forms of caspase-9 and caspase-3 in SMMC-7721 cells. In contrast, the expression of Bcl-2 was decreased, while caspase-8 had no significant change.

CONCLUSION

QNT4 induced the apoptosis of SMMC-7721 cells via inhibiting topoisomerase II activity and modulating mitochondrial-dependent pathways.

Physicochemical Studies and Anticancer Potency of Ruthenium η-p-Cymene Complexes Containing Antibacterial Quinolones

With the aim of exploring the anticancer properties of organometallic compounds with bioactive ligands, Ru(arene) compounds of the antibacterial quinolones nalidixic acid (2) and cinoxacin (3) were synthesized, and their physicochemical properties were compared to those of chlorido(η⁶-p-cymene)(ofloxacinato-κ²O,O)ruthenium(II) (1). All compounds undergo a rapid ligand exchange reaction from chlorido to aqua species. 2 and 3 are significantly more stable than 1 and undergo minor conversion to an unreactive [(cym)Ru(μ-OH)₃Ru(cym)]⁺ species (cym = η⁶-p-cymene). In the presence of human serum albumin 1−3 form adducts with this transport protein within 20 min of incubation. With guanosine 5′-monophosphate (5′-GMP; as a simple model for reactions with DNA) very rapid reactions yielding adducts via its N7 atom were observed, illustrating that DNA is a possible target for this compound class. A moderate capacity of inhibiting tumor cell proliferation in vitro was observed for 1 in CH1 ovarian cancer cells, whereas 2 and 3 turned out to be inactive.

The anti-cancer effects of quinolone antibiotics?

A previous meta-analysis showed that quinolones administered for prophylaxis of infections among cancer patients reduced all-cause mortality. We extracted from the primary trials infection-related and all-cause mortality as reported and assessed the effect of quinolones on non-infection-related mortality through meta-analysis. Among trials comparing quinolones to placebo or no treatment, a significant reduction in non-infection-related mortality was observed (relative risk 0.54, 95% confidence interval 0.32-0.93, 15 trials, 3,320 patients). This finding might represent biased attribution of deaths to infection or might be compatible with an anti-cancer effect of quinolone antibiotics. We present further analyses addressing these possibilities.

Heterocycles [h]fused onto 4-oxoquinoline-3-carboxylic acid, part IV. Convenient synthesis of substituted hexahydro [1,4]thiazepino[2,3-h]quinoline-9-carboxylic acid and its tetrahydroquino[7,8-b]benzothiazepine homolog

Substituted [1,4]thiazepino[2,3-h]quinolinecarboxylic acid 3 is prepared by PPA-catalyzed thermal lactamization of the respective 8-amino-7-[(2-carboxyethyl)thio]-1,4-dihydroquinoline-3-carboxylic acid 9. The latter synthon is obtained by reduction of the 8-nitro-1,4-dihydroquinoline precursor 8 which, in turn, is made accessible via interaction of 3-mercaptopropionic acid with 7-chloro-1-cyclopropyl-6-fluoro-8-nitro-1,4-dihydroquinoline-3-carboxylic acid 7 in the presence of triethylamine. A benzo-homolog of 3, namely tetrahydroquino[7,8-b]benzothiazepine-3-carboxylic acid 6, is analogously prepared via the reaction of 2-mercaptobenzoic acid with 7, followed by reduction of the resulting 7-[(2-carboxyphenyl)thio]-8-nitro product 10 into the corresponding 8-amino derivative 11, and subsequent lactamization. The structures assigned to 3, 6 and 8-11 are based on microanalytical and spectral (IR, MS, NMR) data.

Moxifloxacin enhances antiproliferative and apoptotic effects of etoposide but inhibits its proinflammatory effects in THP-1 and Jurkat cells

Etoposide (VP-16) is a topoisomerase II (topo II) inhibitor chemotherapeutic agent. Studies indicate that VP-16 enhances proinflammatory cytokines secretion from tumour cells, including IL-8, a chemokine associated with proangiogenic effects. Fluoroquinolones inhibit topo II activity in eukaryotic cells by a mechanism different from that of VP-16. The fluoroquinolone moxifloxacin (MXF) has pronounced anti-inflammatory effects in vitro and in vivo. We studied the effects of MXF and VP-16 on purified human topo II activity and further analysed their combined activity on proliferation, apoptosis and caspase-3 activity in THP-1 and Jurkat cells. Moxifloxacin alone slightly inhibited the activity of human topo II; however, in combination with VP-16 it led to a 73% reduction in enzyme activity. VP-16 inhibited cell proliferation in a time and dose-dependent manner. The addition of moxifloxacin for 72 h to low-dose VP-16 doubled its cytotoxic effect in THP-1 and Jurkat cells (1.8- and 2.6-fold decrease in cell proliferation, respectively) (P<0.004). Moxifloxacin given alone did not induce apoptosis but enhanced VP-16-induced apoptosis in THP-1 and Jurkat cells (1.8- and two-fold increase in annexin V positive cells and caspase-3 activity, respectively) (P<0.04). VP-16 induced the release of IL-8 in a time and dose-dependent manner from THP-1 cells. Moxifloxacin completely blocked the enhanced release of IL-8 induced by 0.5 and 1 μg ml⁻¹ VP-16, and decreased IL-8 release from cells incubated for 72 h with 3 μg ml⁻¹ VP-16 (P<0.001). VP-16 enhanced the release of IL-1β and TNF-α from THP-1 cells, whereas the addition of MXF prevented the enhanced cytokine secretion (P<0.001). We conclude that MXF significantly enhances VP-16 cytotoxicity in tumour-derived cells while preventing VP-16-induced proinflammatory cytokine release. This unique combination may have clinical benefits and cytotoxic drug ‘sparing effect’ and should be further studied in vivo.

A chemosensitivity test for superficial bladder cancer based on three-dimensional culture of tumour spheroids

OBJECTIVES

Three-dimensional (3D) spheroids are a good model for studying in vitro chemosensitivity because they reproduce unicellular and multicellular mechanisms of drug resistance. We aimed to develop a chemosensitivity test for intravesical drugs and to also verify the effects of verapamil (VPM) and ciprofloxacin (CIPRO).

METHODS

Cold cup biopsies from 40 superficial bladder tumours were taken, fragmented, and left in culture. 3D-spheroids were obtained and transferred into a 24 multiwell dish containing (1) wells 1-3: 1 mg/ml epirubicin (EPI); (2) 4-6: 1 mg/ml EPI+0.5 mg/ml VPM; (3) 7-9: 1 mg/ml adriamycin (ADR); (4) 10-12: 1 mg/ml thiotepa (THIO); (5) 13-15: 1 mg/ml mitomycin C (MMC); (6) 16-18: 1mg/ml EPI+0.2 mg/ml CIPRO; (7) 19-21: 0.2 mg/ml CIPRO; (8) 22-24: controls. Sensitivity was calculated by using the trypan blue assay.

RESULTS

Evaluability of clinically relevant tests (G1-G2 lesions) was 84% (21 of 25 patients). MMC was the best agent (p<0.001) with mean sensitivity being 50%, followed by THIO (37%), EPI (7%), and ADR (3%). We found no significant difference (p=0.370) between CIPRO and the control, or between EPI+CIPRO and EPI alone (p=0.550). VPM markedly enhanced sensitivity to EPI compared with EPI alone (97% vs. 7%, p<0.001).

CONCLUSIONS

Our assay allows determining sensitivity to several drugs in superficial bladder tumours. It might be used in clinical practice to select the best drug for each patient. It also has experimental utility in investigating the effect of new drugs or combinations. VPM reverted resistance to EPI. CIPRO showed no effect on bladder tumour spheroids.

Effects of a complex mixture of therapeutic drugs at environmental levels on human embryonic cells

The potential risk associated with the presence of low levels of pharmaceuticals in aquatic environments is currently under debate. In this study we investigated the effects of 13 drugs merged to mimic both the association and low concentration (ng/L) profiles detected in the environment. The mixture comprised atenolol, bezafibrate, carbamazepine, cyclophosphamide, ciprofloxacin, furosemide, hydrochlorothiazide, ibuprofen, lincomycin, ofloxacin, ranitidine, salbutamol, and sulfamethoxazole. At environmental exposure levels, the drug mix inhibited the growth of human embryonic cells HEK293, with the highest effect observed as a 30% decrease in cell proliferation compared to controls. Pharmaceuticals activated stress-response signaling protein kinases (ERK1/2), and induced overexpression of glutathione-S-transferase P1 gene. No evidence was found for apoptosis or necrosis in HEK293 cells, although morphological changes were observed. The drug mixture effectively stimulated the expression of cell-cycle progression-mediating genes p16 and p21, with a slight accumulation of cells in the G2/M phase of the cell-cycle. Our results suggest that a mixture of drugs at ng/L levels can inhibit cells proliferation by affecting their physiology and morphology. This also suggests that water-borne pharmaceuticals can be potential effectors on aquatic life.

Implants of noninvasive papillary urothelial carcinoma in peritoneum and ileocolonic neobladder: Support for “seed and soil” hypothesis of bladder recurrence

OBJECTIVES

To explore the underlying mechanism of tumor regrowth in cases of noninvasive urothelial carcinoma that recur in unusual anatomic locations.

METHODS

The pathology files of our institution and the consult service of one of us were searched for cases of noninvasive nonmetastatic urothelial carcinoma with involvement of unusual anatomic sites. Cases in which the mode of spread included direct spread to the adjacent tissue and lymphovascular metastases were excluded. Medical history, including presenting symptoms, and follow-up data were obtained.

RESULTS

Two cases of noninvasive urothelial carcinoma were identified. One had presented as an implant in the peritoneal investment of the bladder dome and the other as multiple implants growing on the benign surface of the colonic mucosa of an orthotopic neobladder distant from the anastomosis site. Both cases had initially presented as noninvasive papillary urothelial carcinoma of the renal pelvis. Although the urinary bladder was free of neoplastic changes at nephroureterectomy, both patients also developed several papillary tumors within the bladder shortly after the removal of the kidney.

CONCLUSIONS

After clinicopathologic correlation, the mode of tumor spread in these cases was best explained by the "seeding/implantation" theory. The urothelial tumor cells in each of these cases demonstrated the ability to implant themselves not only in the urothelium of the bladder but also in the colonic mucosa of a constructed neobladder and on the peritoneal surface.

Antitumor activity of common antibiotics against superficial bladder cancer

OBJECTIVES

The recurrence rate for superficial bladder tumors treated with complete resection averages 88%. Intravesical chemotherapy decreases the recurrence rate by only 14%; thus, new chemotherapeutic agents are needed. Antibiotics are often used to prevent infections after transurethral resection of bladder tumors. Oral intake of antibiotics results in significantly greater concentrations in the urine than in the serum. Our objective was to evaluate four commonly used urinary antibiotics for their cytotoxic activity against bladder cancer cells at clinically relevant concentrations.

METHODS

Three human transitional cell carcinoma lines--HTB9 (grade 2), T24 (grade 3), and TccSup (grade 4)--were exposed to ciprofloxacin, trimethoprim-sulfamethoxazole, cefazolin, or nitrofurantoin at concentrations from 0 (control) to 1000, 1000, 5000, and 2000 microg/mL, respectively, for 96 hours. Cytotoxicity was evaluated using the MTT colorimetric assay. Six replicates were used for each data point, and the results are reported as the mean +/- standard deviation.

RESULTS

Significant cytotoxicity (P <0.001) was seen, starting at 12.5 microg/mL (HTB9, TccSup) and 50 microg/mL (T24) for ciprofloxacin, 31.25 microg/mL (HTB9, TccSup) and 62.5 microg/mL (T24) for trimethoprim-sulfamethoxazole, 19.5 microg/mL (HTB9) and 156.3 microg/mL (T24, TccSup) for cefazolin, and 7.8 microg/mL (HTB9, T24, TccSup) for nitrofurantoin. Cytotoxicity was dose dependent for all four antibiotics, and the maximal effect did not differ among antibiotics.

CONCLUSIONS

Commonly used antibiotics exhibit significant dose-dependent cytotoxicity against bladder cancer cells at concentrations achievable in the urine after oral administration. The administration of antibiotics after transurethral resection of bladder tumors might prevent seeding of cancer cells and thereby decrease the recurrence rate. Preclinical data such as these must be considered in the design of clinical trials addressing recurrence after transurethral resection of bladder tumors.

Human DNA topoisomerase-IIalpha expression as a prognostic factor for transitional cell carcinoma of the urinary bladder

OBJECTIVE

To investigate the immunohistochemical expression of topoisomerase II-alpha (TII-alpha, a nuclear enzyme, the expression of which increases rapidly at the end of the S to G2/M phase and declines when mitosis ends) in bladder urothelial neoplasms (transitional cell carcinoma), and its correlation with grade, stage and survival.

PATIENTS AND METHODS

Histological sections from 57 urothelial neoplasms were stained immunohistochemically for TII-alpha expression; the percentage of positive cells in the area of greatest staining was recorded as the TII-alpha index.

RESULTS

TII-alpha nuclear staining was positive in all the samples except one. The mean (sd) TII-alpha index was 10.7 (5.9) in urothelial neoplasms of low malignant potential (grade 1), 15.5 (5.0) in low-grade (grade 2) and 42.1 (13.4) in high-grade urothelial carcinoma (grade 3). The mean TII-alpha index was 10.7 (5.9), 26.3 (14.8) and 44 (19) in stages pTa, pT1 and pT2, respectively. The TII-alpha index was significant for predicting death from cancer, independently of the stage or grade of the disease (P = 0.019, hazard ratio 1.1).

CONCLUSIONS

A higher TII-alpha index indicates a greater probability of recurrence of disease and lower overall survival. Therefore TII-alpha expression has prognostic value in bladder carcinoma.

Optimal treatment of systemic bacillus Calmette-Guérin infection: investigations in an animal model

PURPOSE

Hematogenous spread of bacillus Calmette-Guerin (BCG) after intravesical instillation for bladder cancer is rare but it may result in systemic infection and hypersensitivity reaction. We investigated fluoroquinolones and steroids in an animal model to improve the therapeutic options in local and systemic BCG infection. Furthermore, the antitumor effectiveness of intravesical BCG with simultaneous application of fluoroquinolones and/or steroids was tested.

MATERIALS AND METHODS

Oral antimicrobial therapy with and without steroids was started immediately after intraperitoneal injection using fluoroquinolones or trimethoprim-sulfamethoxazole. To evaluate the therapeutic options against a hyperergic reaction after repeat systemic BCG infection re-challenge was performed with intraperitoneal BCG 7 days after primary infection and oral therapy was given with fluoroquinolones or trimethoprim-sulfamethoxazole with and without steroids. The influence of continuous oral fluoroquinolone therapy on the antitumor effect of BCG was also tested in the MB 49 orthotopic murine bladder tumor model.

RESULTS

After primary systemic infection fluoroquinolone therapy alone led to significantly prolonged survival in mice (log rank test p = 0.041), whereas trimethoprim-sulfamethoxazole was ineffective. There was no additional effect of steroid administration. Steroids alone led to premature death (log rank test p = 0.022). After secondary BCG infection only steroid treated animals had prolonged survival (log rank test p = 0.032), whereas antimicrobials alone had no effect. The therapeutic efficacy of BCG in the orthotopic bladder tumor model was not affected by continuous oral fluoroquinolones in terms of survival (log rank test p = 0.001) or bladder weight (Wilcoxon test p = 0.001) compared with untreated controls.

CONCLUSIONS

In a mouse model fluoroquinolones had a beneficial effect for primary systemic BCG infections, whereas the hyperergic reaction after repeat BCG infection was susceptible only to steroids. Administering fluoroquinolones during an intravesical treatment course does not affect the antitumor efficacy of BCG.

Chemoprevention of bladder cancer

The data presented herein, although highly supportive for a protective role of various nutrients against bladder cancer, are far from definitive. Many authorities question the validity of current recommendations for nutritional chemoprevention against bladder cancer. The reason for the wide variations reported in epidemiologic studies lies in the nature of observational studies. Dietary studies are limited in their conclusions because the protection afforded by the consumption of a particular nutrient may be multifactorial, with different components of the food exerting potential chemopreventive effects. Furthermore, measuring levels of nutrients in the food intake of populations is confounded by factors that might affect these levels and also the incidence of cancer. For example, vitamin A can come from animal or vegetarian sources. Because animal fat has been identified as a potential carcinogen in man, depending on the source of the vitamin, varying levels of protection might be deduced. In addition, chemoprevention studies using dietary supplements are expected to have mild effects, and large studies would be required to confirm statistical significance. Even with agents such as intravesical chemotherapy, only half the studies achieve statistical significance [29]. Prospective randomized trials with a large sample size, longer follow-up, and an extended duration of treatment are needed to clarify the association between micronutrients and cancer protection. With these caveats in mind, several recommendations can be made. Simple measures, such as drinking more fluids (especially water), can have a profound impact on the incidence of bladder cancer. Vitamins are being extensively studied in chemopreventive trials for different cancers. There is strong evidence for a chemoprotective effect of vitamin A in bladder cancer. The authors recommend 32,000 IU/day of vitamin A initially, with lower doses (24,000 IU) for persons less than 50 kg. Because liver toxicity is a possibility with long-term administration, the dose should be decreased to 16,000 IU after 3 years. High doses of beta-carotene should be avoided based on a large clinical trial reporting a 25% increase in the number of cases of prostate cancer and a statistically significant increase in the incidence of lung cancer. Vitamin B6 has been studied in several clinical trials in bladder cancer. The US-based Veterans Administration cooperative study found benefit for vitamin B6 when given as a single agent. Data for vitamins C and E are insufficient to recommend either agent as stand-alone treatment. Nonetheless, each of these vitamins is known to have beneficial effects, including improved function of the immune system. It is possible that only a small percentage of patients with bladder cancer respond to vitamins B6, C, or E, yet each is safe, nontoxic, and inexpensive. In an effort to pool the efficacy of individual agents and to increase the power of study, the authors evaluated the combination of vitamins A, B6, C, and E in a double-blind trial. The observed 50% 5-year reduction in tumor recurrence was highly significant and greater than would be expected for any of the individual ingredients and suggests that combinations of nutritional agents may be most appropriate. A large-volume study along similar lines is being conducted. Among the numerous other compounds and dietary substances purported to have chemopreventive effect, soybeans, garlic, and green tea stand out as having the greatest promise and can freely be recommended to patients. For synthetically synthesized agents such as celecoxib, piroxicam, or DFMO, recommendations must be deferred until the results of clinical trials are conclusively in favor of their use. Many of the dietary factors found to be protective against bladder cancer are being investigated in other cancers and are beneficial to general health. Although naturally occurring nutrients are ideal, especially because the delicate balance of various micronutrients might be impossible to synthesize in the laboratory, the general population finds it easier to take vitamin supplements. Unfortunately, dietary changes such as decreasing fat and increasing fruit and vegetable intake are more difficult to initiate. There is a mistaken notion that simply because an agent is naturally occurring, it cannot be as beneficial as taking a substance synthesized in the laboratory. Even in a high-risk group such as nuclear-bomb survivors in Japan, high consumption of vegetables and fruit is protective against bladder cancer [44]. Encouraging patients to follow an essentially healthy food habit lifestyle will be a significant contribution in the fight against cancer.