Biomarkers in monitoring for efficacy of immunotherapy and chemoprevention of bladder cancer with dimethylsulfoxide

Effect of an epidermal growth factor receptor tyrosine kinase inhibitor on actin remodeling in an in vitro bladder cancer carcinogenesis model

Alteration of actin remodeling is a marker of malignant-associated field defect and a potential surrogate biomarker for chemoprevention trials. We tested erlotinib, a specific tyrosine kinase inhibitor of epidermal growth factor receptor (EGFR), on actin remodeling in a bladder carcinogenic model consisting of untransformed HUC-PC cells and transformed MC-T11 cells, both derived from the same normal human urothelial clone immortalized by SV40. Erlotinib had a selective growth inhibitory and actin remodeling effect on MC-T11 cells over HUC-PC cells, as examined by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and immunofluorescence labeling with laser scan cytometer analysis, respectively. The IC(50) of untransformed HUC-PC cells was significantly higher than that of transformed MC-T11 cells (P < 0.05, t test). The actin remodeling effect was more prominent at lower dosage levels (1/8-1/4 of IC(50)), which was accompanied by an increased cell adhesion and decreased motility. At higher dosage levels (1/2 of IC(50)), erlotinib induced a decreased adhesion and anoikis (detachment-associated apoptosis). The transformed MC-T11, but not HUC-PC, showed a weak constitutive EGFR phosphorylation activity, which was inhibited by erlotinib in a dose-response manner. However, on epidermal growth factor stimulation, both cell lines showed a similar dose-response inhibitory effect on phosphorylated EGFR and mitogen-activated protein kinase (MAPK; P44/P42) activities, and MAPK inhibitor PD98059 showed no specific effect on erlotinib-induced actin remodeling, suggesting that pathways other than MAPK (P44/P42) may be responsible for erlotinib-induced actin remodeling. The findings provide evidence to support erlotinib-based bladder cancer chemoprevention and using actin remodeling as a marker for erlotinib-based intervention trials.

Biomarker analysis on breast ductal lavage cells in women with and without breast cancer

Recent studies show that morphology based analysis of ductal lavage specimens failed to detect many cancers in women with breast cancer. Such an observation raises doubts about the potential role of ductal lavage in an individual's risk assessment and early detection of breast cancer. We hypothesize that biomarker-based analysis using markers of malignancy field defects including DNA 5c exceeding rate (DNA 5cER) and G-actin might provide a more reliable test for breast cancer risk. The study was performed in 2 phases, the training and validation phase. For the training phase, 36 Chinese women were recruited (13 with breast cancer, 8 with intraductal papilloma and 15 with benign breast diseases). The validation phase included 10 women with cancer and 7 women without cancer. Ductal lavage samples were processed by the ThinPrep technique and evaluated by morphology followed by biomarker analysis using laser scan cytometry (LSC) for G-actin and DNA5cER. In the training phase, biomarker analysis was performed on the 67% (24 of 36) of samples that had over 100 epithelial cells. The sensitivity of DNA5cER was 90% with a specificity of 100%, and G-actin was 100% and 93%, respectively. By contrast, the sensitivity and specificity obtained by cytology alone were 67% and 93%, respectively. Similar results were obtained from the small validation study. Quantitative analysis of biomarkers for G-actin and DNA5cER is feasible and useful in distinguishing benign from malignant breast disease on archived ductal lavage slides. Further studies are warranted to determine the value of these biomarkers in prospective trials.

Ganoderma lucidum extracts inhibit growth and induce actin polymerization in bladder cancer cells in vitro

This study was conducted to investigate chemopreventive effects of Ganoderma lucidum using a unique in vitro human urothelial cell (HUC) model consisted of HUC-PC cells and MTC-11 cells. Ethanol and water extracts of fruiting bodies and spores of the G. lucidum were used to examine growth inhibition, actin polymerization status, and impact of actin remodeling on cell migration and adhesion. Results showed that ethanol extracts had a stronger growth inhibition effect than water extracts. Cell cycle analysis showed that the growth inhibition effect was associated with G2/M arrest. At non-cytotoxic concentrations (40-80 microg/ml), these extracts induced actin polymerization, which in turn inhibited carcinogen 4-aminobiphenyl induced migration in both cell lines. The increased actin polymerization was associated with increased stress fibers and focal adhesion complex formation, however, expression of matrix metalloproteinase-2 and focal adhesion kinase (total and phospholated) were unchanged, which suggests that other mechanisms may be involved.

Tissue microarray analysis of cytoskeletal actin-associated biomarkers gelsolin and E-cadherin in urothelial carcinoma

BACKGROUND

Alterations of expression of the cytoskeletal proteins Gelsolin and E-cadherin have been implicated in urothelial carcinoma tumorigenesis. However, it is not clear how these altered expressions associate with tumor progression, nor is it clear how these protein markers provide prognostic value for urothelial carcinomas.

METHODS

Primary urothelial carcinoma tissue microarrays were constructed for 146 patients with urothelial carcinoma. Where available, four replicate tissue samples of invasive tumor, adjacent dysplastic and in situ lesions, and benign tumors were arrayed for each case, resulting in a total of 1208 tissue spots. Immunohistochemical staining for Gelsolin, E-cadherin, p53, and Ki67 (MIB-1) was performed on the arrays. For each marker, the maximum staining intensity (Max), the percentage of positive staining (Pos), and the product of both Max and Pos (MaxPos) were analyzed.

RESULTS

Compared with the benign fields, the expression of both cytoskeletal proteins decreased in premalignant and malignant lesions. For Gelsolin, decreased MaxPos was seen in premalignant and preinvasive lesions. However, with an increase in tumor grade and stage, there was a gradual increase in Gelsolin (P < 0.05 for both). E-cadherin expression decreases mainly in high-grade lesions (carcinoma in situ and Grade 3 tumors). Univariate and multivariate analyses showed that Gelsolin Max was a strong independent predictor for the probability of tumor recurrence and for early tumor recurrence in high-grade or high-stage tumors, as well as a strong indicator for tumor progression.

CONCLUSIONS

Gelsolin and E-cadherin have distinctive expression patterns. Gelsolin, but not E-cadherin, provides independent prognostic information for high-grade urothelial carcinomas.

Use of markers in defining urothelial premalignant and malignant conditions

Markers have revealed the presence of phenotypically abnormal areas in histologically benign urothelium in bladders containing transitional cell carcinomas. This finding strongly suggests that at least some bladder cancers are associated with changes in the field and that markers can detect these lesions before they reach a grossly malignant stage. Markers have been used clinically for the detection of cancer in patients who are under regular surveillance for recurrence of bladder cancer. Much less information is available regarding the use of markers to detect bladder cancer without a prior history of the disease and for the prediction of which tumors are biologically more aggressive. However, ongoing clinical trials are addressing the latter issue. The type of specimen and its preparation will determine what type of markers can be analyzed. Although marker performance is based upon sensitivity and specificity, the prevalence of bladder cancer in the population being tested will dramatically affect the positive predictive value of an assay. Markers with high positive predictive value are indicators for interventions, such as biopsy, while markers with high negative specific values are useful for avoiding interventions. Cytology is used to detect occult high-grade neoplasms such as carcinoma in situ. While not yet clinically validated, tests with high negative predictive value could be used to decrease the frequency of cystoscopic evaluation. Markers must be validated by testing them prospectively using previously defined cut-off values. Furthermore, markers that will be used to alter treatment should be tested prospectively to determine the safety and cost-effectiveness of this strategy. Recommendations for future work include: (1) evaluation of markers in patients with dysplasia defined by the current pathologic classification; (2) evaluation of markers as indicators of tumor recurrence; (3) evaluation of markers as indicators of tumor progression; and (4) evaluation of markers in chemoprevention studies.

Biomarker risk assessment and bladder cancer detection in a cohort exposed to benzidine

BACKGROUND

Cancer screening with highly sensitive, specific biomarkers that reflect molecular phenotypic alterations is an attractive strategy for cancer control. We examined whether biomarker profiles could be used for risk assessment and cancer detection in a cohort of Chinese workers occupationally exposed to benzidine and at risk for bladder cancer.

METHODS

The cohort consisted of 1788 exposed and 373 nonexposed workers, followed from 1991 through 1997. We assayed urothelial cells from voided urine samples for DNA ploidy (expressed as the 5C-exceeding rate [DNA 5CER]), the bladder tumor-associated antigen p300, and a cytoskeletal protein (G-actin). Workers were stratified into different risk groups (high, moderate, and low risk) at each examination based on a predefined biomarker profile. For workers who developed bladder cancer, tumor risk assessment was analyzed from samples collected 6-12 months before the cancer diagnosis. The associations between risk group and subsequent development of bladder cancer were analyzed by Cox proportional hazards regression analysis and logistic analysis, after adjustment. All statistical tests were two-sided.

RESULTS

Twenty-eight bladder cancers were diagnosed in exposed workers and two in nonexposed workers. For risk assessment, DNA 5CER had 87.5% sensitivity, 86.5% specificity, an odds ratio (OR) of 46.2 (95% confidence interval [CI] = 8.1 to 867.0), and a risk ratio (RR) of 16.2 (95% CI = 7.1 to 37.0); p300 had 50.0% sensitivity, 97.9% specificity, an OR of 40.0 (95% CI = 9.0 to 177.8), and an RR of 37.9 (95% CI = 16.8 to 85.3). The risk of developing bladder cancer was 19.6 (95% CI = 8.0 to 47.9) times higher in workers positive for either the DNA 5CER or p300 biomarkers than in workers negative for both biomarkers and 81.4 (95% CI = 33.3 to 199.3) times higher in workers positive for both biomarkers. G-actin was a poor marker of individual risk.

CONCLUSIONS

Occupationally exposed workers at risk for bladder cancer can be individually stratified, screened, monitored, and diagnosed based on predefined molecular biomarker profiles.

Complexity, Retinoid-Responsive Gene Networks, and Bladder Carcinogenesis

Carcinogenesis involves inactivation or subversion of the normal controls of proliferation, differentiation, and apoptosis. However, these controls are robust, redundant, and interlinked at the gene expression levels, regulation of mRNA lifetimes, transcription, and recycling of proteins. One of the central systems of control of proliferation, differentiation and apoptosis is retinoid signaling. The hRAR alpha nuclear receptor occupies a central position with respect to induction of gene transcription in that when bound to appropriate retinoid ligands, its homodimers and heterodimers with hRXR alpha regulate the transcription of a number of retinoid-responsive genes. These include genes in other signaling pathways, so that the whole forms a complex network. In this study we showed that simple, cause-effect interpretations in terms of hRAR alpha gene transcription being the central regulatory event would not describe the retinoid-responsive gene network. A set of cultured bladder-derived cells representing different stages of bladder tumorigenesis formed a model system. It consisted of 2 immortalized bladder cell lines (HUC-BC and HUC-PC), one squamous cell carcinoma cell line (SCaBER), one papilloma line (RT4), and 4 transitional cell carcinomas (TCC-Sup, 5637, T24, J82) of varying stages and grades. This set of cells were used to model the range of behaviors of bladder cancers. Relative gene expression before (constitutive) and after treatment with 10 microM all-trans-retinoic acid (aTRA) was measured for androgen and estrogen receptor; a set of genes involved with retinoid metabolism and action, hRAR alpha nd beta, hRXR alpha and beta CRBP, CRABP I and II; and for signaling genes that are known to be sensitive to retinoic acid, EGFR, cytokine MK, ICAM I and transglutaminase. The phenotype for inhibition of proliferation and for apoptotic response to both aTRA and the synthetic retinoid 4-HPR was determined. Transfection with a CAT-containing plasmid containing an aTRA-sensitive promoter was used to determine if the common retinoic acid responsive element (RARE)-dependent pathway for retinoid regulation of gene expression was active. Each of the genes selected is known from previous studies to react to aTRA in a certain way, either by up- or down-regulation of the message and protein. A complex data set not readily interpretable by simple cause and effect was observed. While all cell lines expressed high levels of the mRNAs for hRXR alpha and beta that were not altered by treatment with exogenous aTRA, constitutive and stimulated responses of the other genes varied widely among the cell lines. For example, CRABP I was not expressed by J82, T24, 5637 and RT4, but was expressed at low levels that did not change in SCaBER and at moderate levels that decreased, increased, or decreased sharply in HUC-BC, TCC-Sup and HUC-PC, respectively. The expression of hRAR alpha, which governs the expression of many retinoid-sensitive genes, was expressed at moderate to high levels in all cell lines, but in some it was sharply upregulated (TCC-Sup, HUC-PC and J82), remained constant (5637 and HUC-BC), or was down-regulated (SCaBER, T24 and RT4). The phenotypes for inhibition of proliferation showed no obvious relationship to the expression of any single gene, but cell lines that were inhibited by aTRA (HUC-BC and TCC-Sup) were not sensitive to 4-HPR, and vice versa. One line (RT4) was insensitive to either retinoid. Transfection showed very little retinoid-stimulated transfection of the CAT reporter gene with RT4 or HUC-PC. About 2-fold enhancement transactivation was observed with SCaBER, HUC-BC, J82 and T24 cells and 3-8 fold with 5637, TCC-Sup cells. In HUC-BC, a G to T point mutation was found at position 606 of the hRAR alpha gene. This mutation would substitute tyrosine for asparagine in a highly conserved domain. These data indicate that retinoid signaling is probably a frequent target of inactivation in bladder carcinogenesis. (ABSTRAC