The clinical significance of molecular markers to bladder cancer

Intervention of nicotine on MNU-induced bladder cancer in rats

This study examined the effect of nicotine on the expression of mutant p53 (mt-p53) in bladder cancer rats. The rat models of bladder cancer were established by infusing N-methyl-nitroso-urea (MNU, 10 mg/kg every 2 weeks for 8 weeks) into the bladder. Pathological examination on the bladder was conducted to confirm the establishment of the model. All the bladder cancer rats were randomly divided into an MNU group and 3 nicotine groups. In the nicotine groups, the rats were intragastrically administered nicotine at different concentrations (25, 15, 5 mg/kg respectively) 3 times per week for 8 weeks. The mt-p53 expression was detected by the immunohistochemical method. The results showed that rat bladder cancer models developed histopathological changes of bladder transitional cell carcinoma. The positive rate of mt-p53 expression in the 3 nicotine groups (25, 15, 5 mg/kg) was 75.00%, 58.33% and 41.67% by the 14th week, respectively, significantly higher than that in the MNU group (33.33%) (all P<0.05). The mt-p53 expression rate was positively correlated with the medication dose and time (P<0.05). It is concluded that nicotine may play an important role in the development of bladder cancer partially by increasing the expression of mt-p53.

Bladder cancer-associated protein, a potential prognostic biomarker in human bladder cancer

It is becoming increasingly clear that no single marker will have the sensitivity and specificity necessary to be used on its own for diagnosis/prognosis of tumors. Interpatient and intratumor heterogeneity provides overwhelming odds against the existence of such an ideal marker. With this in mind, our laboratory has been applying a long term systematic approach to identify multiple biomarkers that can be used for clinical purposes. As a result of these studies, we have identified and reported several candidate biomarker proteins that are deregulated in bladder cancer. Following the conceptual biomarker development phases proposed by the Early Detection Research Network, we have taken some of the most promising candidate proteins into postdiscovery validation studies, and here we report on the characterization of one such biomarker, the bladder cancer-associated protein (BLCAP), formerly termed Bc10. To characterize BLCAP protein expression and cellular localization patterns in benign bladder urothelium and urothelial carcinomas (UCs), we used two independent sets of samples from different patient cohorts: a reference set consisting of 120 bladder specimens (formalin-fixed as well as frozen biopsies) and a validation set consisting of 2,108 retrospectively collected UCs with long term clinical follow-up. We could categorize the UCs examined into four groups based on levels of expression and subcellular localization of BLCAP protein and showed that loss of BLCAP expression is associated with tumor progression. The results indicated that increased expression of this protein confers an adverse patient outcome, suggesting that categorization of staining patterns for this protein may have prognostic value. Finally, we applied a combinatorial two-marker discriminator using BLCAP and adipocyte-type fatty acid-binding protein, another UC biomarker previously reported by us, and found that the combination of the two markers correlated more closely with grade and/or stage of disease than the individual markers. The implications of these results in biomarker discovery are discussed.

Roles of estrogen receptor alpha and beta in modulating urothelial cell proliferation

We reported previously that both subtypes of estrogen receptors, ERalpha and ERbeta, are expressed by human urothelial cells and mediate estrogen-induced cell proliferation in these cells. The aim of this study was to determine the extent to which each ER subtype contributes to urothelial cell proliferation and their possible involvement in the regulation of the cell cycle. We compared the expression of ERalpha and ERbeta mRNAs and protein quantitatively in primarily cultured human bladder urothelial cells obtained from six individuals with three immortalized urothelial (E6, E7, and UROtsa) and two bladder cancer cell lines (HTB-9 and T24). We found that all these cells express similar levels of ERbeta, but immortalized and cancer cells express much higher amounts of ERalpha than primary cells. Higher levels of ERalpha mRNA were also observed in the biopsies of bladder transitional cell carcinoma compared with sample from the same bladder unaffected by tumor. Using the ERalpha-selective agonist PPT, the ERbeta-selective agonist DPN, and specific small interfering RNA against ERalpha or ERbeta, we found that ERbeta predominantly mediates estrogen-induced G1/S transition and cell proliferation in the primary urothelial cells. By contrast, ERalpha predominantly mediates estrogen-induced G1/S transition and cell proliferation in bladder cancer cell lines. Furthermore, we found that 17beta-estradiol (E(2)) rapidly induces phosphorylation of extracellular signal-regulated kinases, but U0126, a mitogen-activated protein kinase kinase (MEK) inhibitor, does not affect E(2)-induced urothelial cell proliferation. E(2) up-regulated cyclin D1 and cyclin E expression in both the primary and bladder cancer cells, and the cancer cells have higher cyclin D1 and cyclin E expression during G0/G1 phases. Our data suggest that estrogen exerts its effects through different ER subtypes in urothelial cells. Increased expression of ERalpha may contribute to early induction of cyclin D1 and cyclin E during the cell cycle in bladder cancer cells.

A novel magnetic bead-based assay with high sensitivity and selectivity for analysis of telomerase in exfoliated cells from patients with bladder and colon cancer

Telomerase activity is elevated in more than 85% of cancer cells and absent in most of the normal cells and thus represents a potential cancer biomarker. We report its measurement in colon and bladder cancer cells captured using antibody-coated magnetic beads. The cells are lysed and telomerase activity is detected using a biosensor assay that employs an oligonucleotide containing the telomerase recognition sequence also covalently coupled to magnetic beads. Telomerase activity is measured by the incorporation of multiple biotinylated nucleotides at the 3'-end of the oligonucleotide strands during elongation which are then reacted with streptavidin-conjugated horseradish peroxidase. A luminescent signal is generated when hydrogen peroxidase is added in the presence of luminol and a signal enhancer. LOD experiments confirm sensitivity down to ten cancer cell equivalents. The telomerase assay reliably identified patient samples considered by an independent pathological review to contain cancer cells. Samples from normal healthy volunteers were all telomerase negative. The assay, which is amenable to automation, demonstrated high sensitivity and specificity in a small clinical cohort, making it of potential benefit as a first line assay for detection and monitoring of colon and bladder cancer.

The clinical significance of autoantibodies in gastrointestinal malignancies: an overview

Autoimmunity can be associated with cancer and one of the forms of its expression is the development of antibodies to autologous cellular antigens. The types of cellular proteins which induce autoantibody responses in gastrointestinal malignancies are quite varied and include cellular proteins encoded by mutated normal genes (p53), cellular proteins that are overexpressed and/or aberrantly expressed in malignant tissues (carcinoembryonic antigen), inhibitors of apoptosis (survivin and livin), major components of mucus (mucins), surface receptors of apoptosis (Fas) and nuclear-restricted proteins (double-stranded DNA, single-stranded DNA and Sm family proteins). In the past few years, due to the great clinical interest and the advancement in detection techniques, the above list has grown significantly and a large number of cancer-related antigens, which trigger a specific humoral immune response to the host, have also been identified. The authors review the autoantibodies associated with gastrointestinal malignancies and their clinical implications.

Additional Gene Therapy with rAAV-wt-p53 Enhanced the Efficacy of Cisplatin in Human Bladder Cancer Cells

OBJECTIVE

Gene therapy is defined as the treatment of an acquired or inherited disease by transfer of genetic material. The most common strategies in gene therapy of bladder cancer are corrective, inductive and cytotoxic gene therapy. Mutations in the p53 tumor suppressor gene are the most common molecular genetic abnormalities in bladder cancer and p53 gene transfer in the human bladder cancer cell line by adenoviral or other vectors was demonstrated to be cytotoxic. However, so far there has been no report of adeno-associated virus-2 vector-mediated p53 gene deliveries in bladder cancer. In this study, wild-type p53 cDNA was transfected into the bladder cancer cells, using the adeno-associated virus-2 vector, and the capability of rAAV-wt-p53 gene therapy in bladder cancer was evaluated in vitro.

METHOD

Bladder cancer cell lines 5637 were transduced with adeno-associated virus-2 vectors containing wild-type human p53 gene (rAAV-wt-p53). Gene expression and transcriptional activation of p53 was determined by Western blot analysis. The cellular growth inhibition and apoptosis of rAAV-mediated p53 transfection were assessed by flow cytometry. The combination effect of rAAV-wt-p53 and cisplatin was measured by MTT assay.

RESULTS

The virus rAAV efficiently enters the cells and expresses its gene products. The gene product of rAAV-wt-p53 is cytotoxic to bladder cancer cells. The bladder cell line 5637 was found to experience a synergistic killing effect when rAAV-wt-p53 was used in combination with cisplatin.

CONCLUSION

rAAV-mediated p53 gene transfer could offer a powerful novel therapeutic approach in bladder cancer.

Raf1, Aurora-A/STK15 and E-cadherin biomarkers expression in patients with pTa/pT1 urothelial bladder carcinoma; a retrospective TMA study of 246 patients with long-term follow-up

AIMS

The study was designed to evaluate Raf1, Aurora-A/STK15 and E-cadherin (E-CD) protein expression and their prognostic value in patients with pTa/pT1 tumours.

MATERIALS AND METHODS

A tissue microarray of 105 pTa, and 141 pT1 tumours was constructed and sections were immunostained with these three antibodies.

RESULTS

There were significant associations between Raf1 overexpression and tumour grade (p = 0.03), between Aurora-A overexpression/alterations of E-CD and tumour grade and stage (p < 0.001 and p < 0.001). In multiple Cox regression analysis, moderate/strong expression of E-CD seemed to be an independent factor in predicting slower tumour progression (p = 0.003) and Aurora-A overexpression (p = 0.022) displays an independent value in predicting tumour recurrences.

CONCLUSION

Evaluation of E-CD and Aurora-A expressions in tissue of patients with pTa/pT1 UC have been proven to be useful in predicting tumours behavior and Raf1 protein expression seemed to have no potential use in this regard.

C-terminal binding proteins: Emerging roles in cell survival and tumorigenesis

Within a cell, the levels and activity of multiple pro- and anti-apoptotic molecules act in concert to regulate commitment to apoptosis. Whilst the balance between survival and death can be tipped by the effects of single molecules, cellular apoptosis control pathways very often incorporate key transcription factors that co-ordinately regulate the expression of multiple apoptosis control genes. C-terminal binding proteins (CtBPs), which were originally identified through their binding to the Adenovirus E1A oncoprotein, have been described as such transcriptional regulators of the apoptosis program. Specifically, CtBPs function as transcriptional co-repressors, and have been demonstrated to promote cell survival by suppressing the expression of several pro-apoptotic genes. In this review we summarize the evidence supporting a key role for CtBP proteins in cell survival. We also describe the known mechanisms of transcriptional control by CtBPs, and review the multiplicity of intracellular signaling and transcriptional control pathways with which they are known to be involved. Finally we consider these findings in the context of additional known roles of CtBP molecules, and the potential implications that this combined knowledge may have for our comprehension of diseases of cell survival, notably cancer.

Biochemical and molecular markers in renal cell carcinoma: an update and future prospects

Cancer is a big problem in the developed world as well as in developing countries. Renal cell carcinoma (RCC) accounts for approximately 3% of adult malignancies and 90-95% of neoplasms arising from the kidney. RCC is more common in men than in women (2:1), and it most often occurs in patients between the ages of 50-70 years. In all cancers the cancerous cells release particular kind of proteins (called tumour markers) and blood tests are used to detect the presence of these markers. These tumour markers nowadays are an area of interest for oncologists who search for a possible solution in the detection and treatment of RCC. Different kinds of biochemical and molecular markers such as ferritin, MN/CA9, apoptotic index, p53, IL-2, gamma-enolase, CD44, CD95, chromosome instability and loss of heterozygosity have been tested in RCC, but so far no marker fulfils one or the other criteria to be considered as an ideal marker for RCC. This review gives basic and updated information about the different kinds of biomarkers studied in RCC and about the role implementation of genomics and proteomics in RCC.