Immunohistochemical detection of acidic fibroblast growth factor in bladder transitional cell carcinoma

Molecularly Targeted Therapy towards Genetic Alterations in Advanced Bladder Cancer

Despite the introduction of immune checkpoint inhibitors and antibody-drug conjugates to the management of advanced urothelial carcinoma, the disease is generally incurable. The increasing incorporation of next-generation sequencing of tumor tissue into the characterization of bladder cancer has led to a better understanding of the somatic genetic aberrations potentially involved in its pathogenesis. Genetic alterations have been observed in kinases, such as FGFRs, ErbBs, PI3K/Akt/mTOR, and Ras-MAPK, and genetic alterations in critical cellular processes, such as chromatin remodeling, cell cycle regulation, and DNA damage repair. However, activating mutations or fusions of FGFR2 and FGFR3 remains the only validated therapeutically actionable alteration, with erdafitinib as the only targeted agent currently approved for this group. Bladder cancer is characterized by genomic heterogeneity and a high tumor mutation burden. This review highlights the potential relevance of aberrations and discusses the current status of targeted therapies directed at them.

A place for precision medicine in bladder cancer: targeting the FGFRs

Bladder tumors show diverse molecular features and clinical outcome. Muscle-invasive bladder cancer has poor prognosis and novel approaches to systemic therapy are urgently required. Non-muscle-invasive bladder cancer has good prognosis, but high recurrence rate and the requirement for life-long disease monitoring places a major burden on patients and healthcare providers. Studies of tumor tissues from both disease groups have identified frequent alterations of FGFRs, including mutations of FGFR3 and dysregulated expression of FGFR1 and FGFR3 that suggest that these may be valid therapeutic targets. We summarize current understanding of the molecular alterations affecting these receptors in bladder tumors, preclinical studies validating them as therapeutic targets, available FGFR-targeted agents and results from early clinical trials in bladder cancer patients.

A combination treatment with DNA methyltransferase inhibitors and suramin decreases invasiveness of breast cancer cells

The treatment of patients with invasive breast cancer remains a major issue because of the acquisition of drug resistance to conventional chemotherapy. Here we propose a new therapeutic strategy by combining DNA methyltransferase inhibitors (DMTIs) with suramin. Cytotoxic effects of suramin or combination treatment with DMTIs were determined in highly invasive breast cancer cell lines MDA-MB-231, BT-20 and HCC1954, or control cells. In addition, effects on cell invasion were determined in 3-dimensional cell culture assays. DMTI-mediated upregulation of Protein Kinase D1 (PKD1) expression was shown by Western blotting. Effects of suramin on PKD1 activity was determined in vitro and in cells. The importance of PKD1 in mediating the effects of such combination treatment in cell invasion was demonstrated using 3D cell culture assays. A proof of principal animal experiment was performed showing that PKD1 is critical for breast cancer growth. We show that when used in combination, suramin and DMTIs impair the invasive phenotype of breast cancer cells. We show that PKD1, a kinase that previously has been described as a suppressor of tumor cell invasion, is an interface for both FDA-approved drugs, since the additive effects observed are due to DMTI-mediated re-expression and suramin-induced activation of PKD1. Our data reveal a mechanism of how a combination treatment with non-toxic doses of suramin and DMTIs may be of therapeutic benefit for patients with aggressive, multi-drug resistant breast cancer.

A Decade of FGF Receptor Research in Bladder Cancer: Past, Present, and Future Challenges

Fibroblast growth factors (FGFs) orchestrate a variety of cellular functions by binding to their transmembrane tyrosine-kinase receptors (FGFRs) and activating downstream signalling pathways, including RAS/MAPK, PLCγ1, PI3K, and STATs. In the last ten years, it has become clear that FGF signalling is altered in a high proportion of bladder tumours. Activating mutations and/or overexpression of FGFR3 are common in urothelial tumours with low malignant potential and low-stage and -grade urothelial carcinomas (UCs) and are associated with a lower risk of progression and better survival in some subgroups. FGFR1 is not mutated in UC, but overexpression is frequent in all grades and stages and recent data indicate a role in urothelial epithelial-mesenchymal transition. In vitro and in vivo studies have shown that FGFR inhibition has cytotoxic and/or cytostatic effects in FGFR-dependent bladder cancer cells and FGFR-targeted agents are currently being investigated in clinical studies for the treatment of UC. Urine-based tests detecting common FGFR3 mutations are also under development for surveillance of low-grade and -stage tumours and for general population screening. Overall, FGFRs hold promise as therapeutic targets, diagnostic and prognostic markers, and screening tools for early detection and clinical management of UC.

Altered splicing of FGFR1 is associated with high tumor grade and stage and leads to increased sensitivity to FGF1 in bladder cancer

Fibroblast growth factor receptors (FGFRs) play key roles in proliferation, differentiation, and tumorigenesis. Previously, we demonstrated that FGFR1 expression is increased in urothelial carcinoma cell lines and tumors, which promotes proliferation and survival via activation of the mitogen-activated protein kinase (MAPK) pathway. Here we examined splice variants of FGFR1 in both urothelial carcinoma cell lines and tumors. Two known FGFR1 IIIc splice variants (FGFR1α and FGFR1β) were expressed. FGFR1β lacks exon 3 of FGFR1α, removing the first Ig loop of the extracellular domain. Both isoforms were expressed at similar levels in normal urothelial cells, but FGFR1β was expressed at higher levels in most tumor cell lines. In tumor tissues, expression levels were higher than in controls, and the FGFR1β:FGFR1α ratio was significantly increased in association with tumor stage and grade. When FGFR1α and FGFR1β were expressed in urothelial cells, no differences in signaling were observed. FGFR1-induced proliferation paralleled MAPK pathway activation. The relative activation of FGFR1β and FGFR1α by all known mammalian FGFs was examined. Both isoforms were activated by the same FGFs, but the level of activation differed. FGFR1β showed higher affinity for low concentrations of FGF1, leading to enhanced signaling and increased proliferation. An FGFR1α-to-FGFR1β isoform switch and increased FGF1-induced activation of FGFR1β may result in a proliferative advantage that plays a key role during bladder tumor progression.

Fibroblast growth factor receptor 1 promotes proliferation and survival via activation of the mitogen-activated protein kinase pathway in bladder cancer

Fibroblast growth factor receptors (FGFR) play key roles in proliferation, differentiation, and tumorigenesis. Many urothelial carcinomas contain activating point mutations or increased expression of FGFR3. However, little is known about the role of other FGFRs. We examined FGFR expression in telomerase-immortalized normal human urothelial cells, urothelial carcinoma cell lines, and tumor samples and showed that FGFR1 expression is increased in a high proportion of cell lines and tumors independent of stage and grade. To determine the role of FGFR1 in low-stage bladder cancer, we overexpressed FGFR1 in telomerase-immortalized normal human urothelial cells and examined changes in proliferation and cell survival in response to FGF2. FGFR1 stimulation increased proliferation and reduced apoptosis. To elucidate the mechanistic basis for these alterations, we examined the signaling cascades activated by FGFR1. FRS2alpha and PLCgamma were activated in response to FGF2, leading to activation of the mitogen-activated protein kinase pathway. The level of mitogen-activated protein kinase activation correlated with the level of cyclin D1, MCL1, and phospho-BAD, which also correlated with FGFR-induced proliferation and survival. Knockdown of FGFR1 in urothelial carcinoma cell lines revealed differential FGFR1 dependence. JMSU1 cells were dependent on FGFR1 expression for survival but three other cell lines were not. Two cell lines (JMSU1 and UMUC3) were dependent on FGFR1 for growth in soft agar. Only one of the cell lines tested (UMUC3) was frankly tumorigenic; here, FGFR1 knockdown inhibited tumor growth. Our results indicate that FGFR1 has significant effects on urothelial cell phenotype and may represent a useful therapeutic target in some cases of urothelial carcinoma.

Histone deacetylase inhibitors: mechanisms and clinical significance in cancer: HDAC inhibitor-induced apoptosis

Epigenic modifications, mainly DNA methylation and acetylation, are recognized as the main mechanisms contributing to the malignant phenotype. Acetylation and deacetylation are catalyzed by specific enzymes, histone acetyltransferases (HATs) and histone deacetylases (HDACs), respectively. While histones represent a primary target for the physiological function of HDACs, the antitumor effect of HDAC inhibitors might also be attributed to transcription-independent mechanisms by modulating the acetylation status of a series of non-histone proteins. HDAC inhibitors may act through the transcriptional reactivation of dormant tumor suppressor genes. They also modulate expression of several other genes related to cell cycle, apoptosis, and angiogenesis. Several HDAC inhibitors are currently in clinical trials both for solid and hematologic malignancies. Thus, HDAC inhibitors, in combination with DNA-demethylating agents, chemopreventive, or classical chemotherapeutic drugs, could be promising candidates for cancer therapy. Here, we review the molecular mechanisms and therapeutic potential of HDAC inhibitors for the treatment of cancer.

Aberrant fibroblast growth factor receptor signaling in bladder and other cancers

Fibroblast growth factors (FGFs) are potent mitogens, morphogens, and inducers of angiogenesis, and FGF signaling governs the genesis of diverse tissues and organs from the earliest stages. With such fundamental embryonic and homeostatic roles, it follows that aberrant FGF signaling underlies a variety of diseases. Pathological modifications to FGF expression are known to cause salivary gland aplasia and autosomal dominant hypophosphatemic rickets, while mutations in FGF receptors (FGFRs) result in a range of skeletal dysplasias. Anomalous FGF signaling is also associated with cancer development and progression. Examples include the overexpression of FGF2 and FGF6 in prostate cancer, and FGF8 overexpression in breast and prostate cancers. Alterations in FGF signaling regulators also impact tumorigenesis, which is exemplified by the down-regulation of Sprouty 1, a negative regulator of FGF signaling, in prostate cancer. In addition, several FGFRs are mutated in human cancers (including FGFR2 in gastric cancer and FGFR3 in bladder cancer). We recently identified intriguing alterations in the FGF pathway in a novel model of bladder carcinoma that consists of a parental cell line (TSU-Pr1/T24) and two sublines with increasing metastatic potential (TSU-Pr1-B1 and TSU-Pr1-B2), which were derived successively through in vivo cycling. It was found that the increasingly metastatic sublines (TSU-Pr1-B1 and TSU-Pr1-B2) had undergone a mesenchymal to epithelial transition. FGFR2IIIc expression, which is normally expressed in mesenchymal cells, was increased in the epithelial-like TSU-Pr1-B1 and TSU-Pr1-B2 sublines and FGFR2 knock-down was associated with the reversion of cells from an epithelial to a mesenchymal phenotype. These observations suggest that modified FGF pathway signaling should be considered when studying other cancer types.

The clinical significance of molecular markers to bladder cancer

Stage and grade of transitional cell carcinoma are currently the most useful tools for taking therapeutic decisions and evaluating the prognosis of bladder cancer patients. However, as there are remarkable differences in biological behavior and "biological potential" of tumors classified in the same stage, it is very difficult to predict which superficial tumors will recur and which tumors will give distant metastases. During the last two decades, the better understanding of the molecular mechanisms involved in carcinogenesis and tumor progression has provided a large number of molecular markers of bladder cancer, with a potential diagnostic and prognostic value. This article reviews comprehensively the molecular role and evaluates the clinical significance and the perspectives of these molecular markers. We concluded that, although at the moment there is not a single marker able to predict with accuracy the biological potential of bladder cancer, the most promising markers, at this point, are deletions of chromosome 9, and the tumor suppressor gene p53. Clinical studies are in progress for the assessment of other biological molecules with prognostic potential, such as the E-cadherin, the protein p120, and the telomerase.

Metastasis markers in bladder cancer: a review of the literature and clinical considerations

Cancer invasion and metastasis develop through a sequence of processes involving loss of cell-cell and cell-matrix adhesions, proteolysis and induction of angiogenesis. We reviewed the current literature on the molecules that have been shown to play a significant role in these three steps of metastatisation in bladder cancer (BC) cells and their host microenvironment. Particular emphasis was given to markers that are assessable through immunohistochemistry and for which an additional prognostic value over the TNM variables has been recognized, in order to identify a subset of tumour markers readily available for application in daily clinical practice. We conclude that markers such as E-cadherin, Sialosyl-LeX, laminin, collagen IV, TSP-1 and MVD are useful prognostic markers, alpha, beta, and gamma catenin, MMP-2 and -9, uPAR, PD-ECGF and Bfgf can be considered potentially useful, while research on CD44, MMP-1 and -3, uPA, cathepsin D and VEGF has proved inconclusive. Further research in this field should concentrate on the molecules listed in the first group.

Effects of sequential treatments with chemotherapeutic drugs followed by TRAIL on prostate cancer in vitro and in vivo

BACKGROUND

Tumor necrosis factor related apoptosis-inducing ligand/Apo2 ligand (TRAIL/Apo-2L) is a novel anticancer agent, capable of inducing apoptosis preferentially in tumor and transformed cells. TRAIL-R1/death receptor (DR)4 and TRAIL-R2/DR5 are members of the tumor necrosis factor (TNF) receptor family, and can be activated by the TRAIL. We examined the clinical potential of chemotherapeutic drugs and TRAIL for the treatment of prostate cancer.

METHODS

Prostate and bladder cancer cells were exposed to chemotherapeutic drugs (paclitaxel, vincristine, vinblastine, etoposide, doxorubicin, and camptothecin) and TRAIL. Cell viability was measured by sodium 3'[1-(phenylaminocarbonyl)-3,4-tetrazolium]-bis (4-methoxy-6-nitro) assay; expressions of death receptors and Bcl-2 family members were measured by Western blotting, ELISA and ribonuclease protection assay. PC-3 tumor cells xenografted athymic nude mice were exposed to chemotherapeutic drugs and TRAIL, either alone or in combination, to measure tumor growth and survival of mice. Apoptosis was measured by annexin V-FITC/propidium iodide staining, and terminal deoxynucleotidyltransferase-mediated nick end labeling assay. Caspase-3 activity was measured by the Western blotting and immunohistochemistry.

RESULTS

TRAIL induced apoptosis with varying sensitivity. Chemotherapeutic drugs (paclitaxel, vincristine, vinblastine, etoposide, doxorubicin, and camptothecin) significantly augmented TRAIL-induced apoptosis in cancer cells through up-regulation of DR4, DR5, Bax, and Bak, and induction of caspase activation. Mitochondrial pathway enhanced the synergistic interactions between drugs and TRAIL. The sequential treatment of mice with chemotherapeutic drugs followed by TRAIL induced caspase-3 activity, and apoptosis, inhibited angiogenesis, completely eradicated the established tumors, and enhanced survival of mice.

CONCLUSIONS

Chemotherapeutic drugs can be used to enhance the therapeutic potential of TRAIL in prostate cancer.

Molecular pathways in bladder cancer

The aim of this review is to provide a contemporary outline of our current understanding of the molecular and genetic events associated with tumorigenesis and the progression of bladder cancer. A comprehensive review of the literature was performed on the molecular alterations associated with transitional cell carcinoma (TCC) of the bladder. Intense research efforts are being made to better identify and characterize various bladder cancers and their true biologic potential. The need to predict which superficial tumors will recur or progress, and which invasive tumors will metastasize has led to a much better understanding of the molecular pathways associated with bladder cancer. The molecular changes that occur in TCC of the bladder are numerous and can be categorized into: (1) chromosomal alterations leading to carcinogenesis, (2) loss of cell cycle regulation accounting for cellular proliferation, and (3) metastasis, guided by events such as angiogenesis. It is becoming apparent that the accumulation of genetic and molecular changes ultimately determines a tumors phenotype and subsequent clinical behavior. At the present time, conventional histopathologic evaluation of bladder cancer (tumor grade and stage) is inadequate to accurately predict the behavior of most bladder tumors. While new laboratory techniques have allowed us to better understand how bladder cancer develops and ultimately progresses, few of these techniques are currently available for use in the clinical setting. The ultimate goal is to develop reliable prognostic markers which will accurately predict not only the expected clinical course of an individual bladder tumor but also the response of that tumor to currently available therapies. More importantly, this information may be employed in the future to dictate altogether new treatments for the prevention and/or stabilization of the early molecular events that lead to the development of bladder cancer.

Fibroblast growth factors and their receptors in urological cancers: basic research and clinical implications

Because therapeutical options for advanced urological cancers are limited, the understanding of key elements responsible for invasion and metastasis is very important. It has been hypothesized that progression to malignant growth is associated with a dysregulation of growth factors and/or their receptors. In the last few years, signaling pathways of the fibroblast growth factor (FGF) family have been subject to intense investigation. Fibroblast growth factors constitute one of the largest families of growth and differentiation factors for cells of mesodermal and neuroectodermal origin. The family comprises two prototypic members, acidic FGF (aFGF) and the basic FGF (bFGF), as well as 21 additionally related polypeptide growth factors that have been identified to date. FGFs are involved in many biological processes during embryonic development, wound healing, hematopoesis, and angiogenesis. In prostate, bladder, and renal cancers, FGFs regulate the induction of metalloproteinases (MMP) that degrade extracellular matrix proteins, thus facilitating tumor metastasis. Probably due to their potent angiogenic properties, aFGF and bFGF have received the most attention. However, there is increasing evidence that other FGFs also play crucial roles in tumors of the prostate, bladder, kidney, and testis. This review will discuss the different elements involved in FGF signaling and summarize the present knowledge of their biological and clinical relevance in urological cancers.

Biomarkers for the detection of bladder cancer

In this subject review, a series of morphology-based and molecular markers were compared with urinary cytology for the detection of recurrent urothelial neoplasia. Among the various biomarkers reviewed, the average published sensitivity and specificity for the Bard BTA test was 60% and 77%; the NMP22 Test was 67% and 72%; the telomerase assay was 77% and 85%; and the microsatellite assay was 89% and 100%. DNA ploidy measurements and immunoassays designed to detect keratins, proteins, hyaluronidase, growth factors, cell adhesion molecules, fibrinogen degradation products, cell cycle regulators, and molecular markers were also included. Although the performance features of these biomarkers have varied and the cytologic methods to which they have been compared have not been standardized, several of the procedures have received considerable support from urologists as assisting them in the management of their patients.

A rat model with an isolated bladder in situ

This paper describes our method for producing a rat model with an isolated bladder in situ in which the bladder makes no contact with urine. First, the right kidney was removed, then an external catheter was placed in the right ureter for bladder infusions, and next the left ureter was anatomosed to the proximal part of the descending colon. The animals were treated with antibiotics, and saline was infused daily into the bladder in order to prevent atrophy. This in situ model is considered to be useful in studies investigating the influence of specific compounds, such as carcinogens, on the bladder and its urothelium.

Advances in angiogenesis research: relevance to urological oncology

PURPOSE

Important advances in angiogenesis research are reviewed along with recent data implicating angiogenesis in the pathogenesis of urological malignancies.

MATERIALS AND METHODS

The current understanding of angiogenesis and its importance in tumor biology is summarized. The rationale for anti-angiogenic therapy is reviewed and the clinical experience with these agents is discussed. An extensive literature search of angiogenesis in urological malignancies was performed.

RESULTS

Quantitative immunohistochemistry for endothelial antigens suggests that, as is the case with many other tumors, induction of angiogenesis contributes to the malignant phenotype of prostate and bladder carcinomas. Anti-angiogenic agents have demonstrated efficacy against urological tumors in experimental systems, and recent data suggest that these agents may also be useful for chemoprophylactic purposes. Putative angiogenesis inducers specific for each of the major urological malignancies have been identified. Quantitation of the expression of angiogenesis inducers and estimation of microvessel density have demonstrated prognostic value for urological malignancies.

CONCLUSIONS

The available data indicate that angiogenesis has an important role in the progression and metastasis of urological malignancies. Preclinical data coupled with experience in other cancers indicate that combining anti-angiogenic therapy with conventional treatment modalities has the potential to improve dramatically our management of these malignancies. Further research will be needed to define the mechanisms controlling angiogenesis in urological malignancies and to determine if any of the angiogenic correlates will be of genuine clinical use. The rapid pace of research in this field suggests that this aspect of tumor biology will soon have an increasingly important role in the evaluation and treatment of urological cancers.

Modulation of intra-epithelial expansion of human T24 bladder-carcinoma cells in murine urothelium by growth factors and extracellular-matrix components

The high recurrence rate of bladder cancer is probably due to an efficient repopulation of the bladder by residual transformed cells after resection of the tumour. However, the regenerating capacity of the normal urothelial cells is very high. To study the balance between regenerating normal urothelium and out-growth of transformed urothelial cells, we recently developed an in vitro co-cultivation model. With this model system we studied the effects of growth factors and extracellular-matrix components on the intra-epithelial expansion of human T24 bladder-carcinoma cells in primary mouse-bladder explants. Exposure of the cultures to acidic fibroblast growth factor (aFGF) and laminin led to a dramatic increase in the number of invasive T24 cells into the primary urothelium. Epidermal growth factor (EGF) and collagen types I and IV counteracted the infiltration of individual T24 cells. EGF, aFGF, laminin and collagen types I and IV did not directly affect the migration and proliferation of T24 cells. Apparently, the efficacy of invasion of transformed urothelial cells into primary urothelium is not only dependent on the intrinsic characteristics of the transformed cells, but can be influenced to a considerable extent by exogenous components exerting their influence on the normal urothelium. The clinical relevance of this observation needs to be studied further.

Clinical prognostic significance of tumour angiogenesis

BACKGROUND

The importance of tumour angiogenesis in the process of tumour growth and metastasis has recently gained wide acceptance. This has lead to intense investigation into the biology of tumour angiogenesis and its clinical significance. An understanding of angiogenesis may allow therapeutic modulation in order to interrupt the progression from tumourigenesis to metastatic disease and control growth of distant metastases.

DESIGN

A review was undertaken of studies relating clinical outcome to the assessment of tumour angiogenesis in patients with cancer.

RESULTS

Studies have been recently reported in a variety of tumours, particularly early breast cancer and melanoma. Quantitative pathology, using microvessel counting, has been the main method applied. However assessment of angiogenic growth factors may provide an alternative. In early breast cancer many studies have shown a worse prognosis for those patients with highly vascular tumours. The prognostic influence of tumour angiogenesis is independent of conventional prognostic indicators. Similar, although more varied results, have been obtained in studies of melanoma and other tumour types.

CONCLUSION

Tumour angiogenesis, as assessed with quantitative pathology, is an important prognostic indicator in early breast cancer and possibly in other tumour types. Further confirmatory studies are required before this indicator is routinely used to guide treatment selection. Assessment of tumour angiogenesis will be increasingly important in the investigation of new therapies aimed at inhibiting angiogenesis or targeting tumour vasculature.