Novel Antiangiogenic Therapies for Renal Cell Cancer

Evaluation of plasma and tissue S100A4 protein and mRNA levels as potential markers of metastasis and prognosis in clear cell renal cell carcinoma

OBJECTIVES

To investigate levels of S100A4 protein in plasma and S100A4 mRNA in tumours from patients with clear cell renal cell carcinoma (CCRCC), and correlate these with metastasis, survival and levels of vascular endothelial growth factor (VEGF).

METHODS

Plasma S100A4 and VEGF protein concentrations were measured using enzyme-linked immuno sorbent assays in 39 healthy subjects and 68 consecutive patients with untreated CCRCC. Levels of S100A4 and VEGF mRNA in tumour and matched control (healthy) tissue samples were measured using realtime quantitative reverse transcription- polymerase chain reaction. Findings were analysed with respect to clinico pathological characteristics.

RESULTS

Plasma VEGF concentrations were higher in patients with CCRCC than in healthy subjects. S100A4 and VEGF mRNA levels were up-regulated in CCRCC tumour tissue compared with control tissue samples. Logistic regression analysis revealed that up-regulated tumour S100A4 and VEGF mRNA levels were independent risk factors for the presence of invasion and/or metastasis.

CONCLUSIONS

S100A4 and VEGF are associated with tumour invasion and metastasis, and may be useful prognostic markers in patients with CCRCC. S100A4 and VEGF may represent potential targets for therapeutic intervention.

Promoter methylation of DAPK1, E-cadherin and thrombospondin-1 in de novo and therapy-related myeloid neoplasms

DNA methylation is one of the major epigenetic changes in human cancers, leading to silencing of tumor suppressor genes, with a pathogenetic role in tumor development and progression in myelodysplastic syndromes (MDS) and acute myeloid leukemia (AML). Methylation of key promoter regions, induced by cytotoxic therapy together with complex genetic changes, is important in the biology of therapy-related myeloid neoplasms (t-MN). We were interested in the characterization of the methylation pattern of AML and MDS de novo and therapy-related. We studied 385 patients (179 females, 206 males), of a median age of 66 years (range 16-98 years). There were 105 MDS, 208 de novo AML and 72 t-MN (45 MDS and 27 AML). Using a methylation-specific PCR, we studied the promoter methylation status of E-cadherin (CDH1), TSP1 and DAP-Kinase 1. These genes have been shown to be involved in the malignant transformation, interfering with angiogenesis, interaction with micro-environment, apoptosis and xenobiotic detoxification. We found no associations between promoter hypermethylation and gender or age at the time of initial diagnosis. In patients with MDS, there were no associations between hypermethylation and clinical characteristics, including IPSS score, WHO classification and cytogenetics. DAPK1 was more frequently methylated in t-MDS/AML when compared to de novo MDS and AML (39% vs 15.3% and 24.4%, p=0.0001), while methylation of CDH1 was similar in t-MDS/AML and AML (51% and 53.4%), but less frequent in de novo MDS (29%) (p=0.003). In the t-MDS/AML group, we found that the methylation pattern appeared to be related to the primary tumor, with DAPK1 more frequently methylated in patients with a previous lymphoproliferative disease (75% vs 32%, p=0.006). On the other hand, methylation of CDH1 was associated to radiotherapy for the primary malignancy (84.5% vs 38%, p=0.003). TSP1 hypermethylation was rare and not characteristic of t-MDS/AML. In 177 patients studied for concurrent methylation of several promoters, t-MN and AML de novo were significantly more frequently hypermethylated in 2 or more promoter regions than de novo MDS (20% vs 12.4%, p<0.001). Chemotherapy and individual genetic predisposition have a role in t-MDS/AML development, the identification of specific epigenetic modifications may explain complexity and genomic instability of these diseases and give the basis for targeted-therapy. The significant association with previous malignancy subtypes may underlie a likely susceptibility to methylation of specific targets and a role for constitutional epimutations as predisposing factors for the development of therapy-related myeloid neoplasm.

The expression of thrombospondin-1 and p53 in clear cell renal cell carcinoma: its relationship to angiogenesis, cell proliferation and cancer specific survival

PURPOSE

We evaluated possible associations among thrombospondin-1, p53 expression, microvessel density, cell proliferation index, nuclear grade, tumor stage and continuously coded tumor size in clear cell renal cell carcinoma. The value of thrombospondin-1 as a prognostic marker in clear cell renal cell carcinoma was examined.

MATERIALS AND METHODS

A total of 172 consecutive patients with clear cell renal cell carcinoma treated with radical nephrectomy were initially enrolled in the study. However, due to technical problems and lack of material 12 cases were excluded from analysis. A total of 68 patients (43%) died of renal cell carcinoma and 46 (29%) died of other diseases. Median followup for the surviving 42 patients (29%) was 13.8 years. The expression of thrombospondin-1, Ki-67 (proliferation index), p53 and microvessel density were analyzed without knowledge of the clinical outcome on formalin fixed, paraffin embedded tissues.

RESULTS

Low expression of thrombospondin-1 was significantly associated with advanced stage (p <0.001), high nuclear grade (p = 0.001), positive p53 status (p <0.001), high proliferation index (p = 0.001), high microvessel density (p = 0.036) and tumor progression (p = 0.006). On univariate analysis thrombospondin-1, microvessel density, proliferation index, p53 over expression, TNM stage, Fuhrman nuclear grade (p <0.001) and continuously coded tumor size (p = 0.002) had a significant impact on survival. Multivariate analysis revealed TNM stage, thrombospondin-1, p53, Ki-67 (proliferation index) and microvessel density were independent predictors of cancer specific survival.

CONCLUSIONS

Thrombospondin-1 expression is strongly associated with prognostic tumor features in clear cell renal cell carcinoma and is an independent prognostic factor for cancer specific survival. Our findings revealed a significant correlation among p53, proliferation index, microvessel density and thrombospondin-1 expression, and indicate that thrombospondin-1 may have an impact on angiogenesis, proliferation and tumor aggressiveness in clear cell renal cell carcinoma.

Molecular Pathology of the Genitourinary Tract: Molecular Pathology of Kidney and Testes

With the advent of newer molecular technologies, our knowledge of cellular mechanisms with tumors of the kidney and testis has grown exponentially. Molecular technologies have led to better understanding of interplay between the von Hippel-Lindau gene and angiogenic cytokines in renal cancer and isochromosome 12p in testicular neoplasms. The result has been development of antiangiogenic-targeted therapy within recent years that has become the mainstay treatment for metastatic renal cell cancer. In the near future, classification and diagnosis of renal and testicular tumors through morphologic analysis will be supplemented by molecular information correlating to prognosis and targeted therapy. This article outlines tumor molecular pathology of the kidney and testis encompassing current genomic, epigenomic, and proteonomic findings.

Human matrix metalloproteinases: characteristics and pathologic role in altering mesangial homeostasis

Matrix metalloproteinases are zinc dependent endopeptidases belonging to the M10 family of the metalloproteinase superfamily. They are ubiquitous enzymes, structurally and functionally related, with a high degree of sequence homology. They are primarily involved in extracellular matrix (ECM) turn-over and cell migration through their expanding repertoire of substrate affinities. Twenty three different forms of human MMPs have been described to be arranged in eight distinct structural classes. Their interactions with tissue inhibitors of metalloproteinases (TIMPs), and other indigenous inhibitors have been well documented. This manuscript reviews pertinent information available on matrix metalloproteinases and TIMPs in the literature. Light chain-mediated glomerular injury represents an excellent example of how metalloproteinases participate in altering mesangial homeostasis. Investigations regarding these conditions have shown that the physico-chemical characteristics of the light chains govern the pattern of renal damage that will ensue with the mesangium representing the critical site where pathological alterations are centered. The mesangium is either replaced or expanded depending on the light chains involved in the pathologic process.

Evaluation of interferon alpha-2B and thalidomide in patients with disseminated malignant melanoma, phase 2, SWOG 0026

BACKGROUND

Southwest Oncology Group protocol 0026 evaluated interferon alpha-2b plus thalidomide in patients with disseminated melanoma. Endpoints were 6-month progression-free survival rate, response rate, and toxicity.

METHODS

Twenty-six patients with Stage IV melanoma, measurable or nonmeasurable disease, performance status of 0-2, and adequate renal and hepatic functions were registered. One prior systemic therapy for Stage IV disease was required. Interferon was administered subcutaneously (1 million U) twice daily; thalidomide was orally administered (200-400 mg) each evening in a dose-escalating manner. Response evaluations using Response Evaluation Criteria in Solid Tumors were performed every 8 weeks.

RESULTS

After 2 sudden deaths and 1 grade 4 treatment-related pulmonary embolism, this study was temporarily closed. One patient with deep-vein thrombosis and 2 with grade 3 cardiac arrhythmias were reported. The relationship of these events to the treatment was worrisome but not definitive. Grade 3 treatment-related adverse events occurred in 14 of 26 patients. Because of concern for patient safety the study was permanently closed. No treatment responses were seen in the 22 evaluable patients. Estimated 6-month progression-free survival rate was 15% (95% confidence interval [CI], 2%-29%), estimated 6-month overall survival was 58% (95% CI, 39%-77%), and estimated response probability was 0 of 22 (95% CI, 0%-15%).

CONCLUSIONS

This regimen demonstrated a lack of response and was associated with multiple severe toxicities. Further investigation of interferon alpha-2b and thalidomide in this dose and schedule is not warranted.

Renal epithelial neoplasms: diagnostic applications of gene expression profiling

Renal cell carcinoma (RCC) is the most common form of kidney cancer in adults. RCC is a significant challenge for pathologic diagnosis and clinical management. The primary approach to diagnosis is by light microscopy, using the World Health Organization (WHO) classification system, which defines histopathologic tumor subtypes with distinct clinical behavior and underlying genetic mutations. However, light microscopic diagnosis of RCC subtypes can be difficult due to variable histology, morphologic features shared by tumor subtypes, and a growing frequency of small tumor biopsies with limited morphologic information. In addition to these diagnostic problems, the clinical behavior of RCC is highly variable, and therapeutic response rates are poor. Few clinical assays are available to predict outcome in RCC or correlate behavior with histology. Therefore, novel RCC classification systems based on gene expression should be useful for diagnosis, prognosis, and treatment. Recent microarray studies have shown that renal tumors are characterized by distinct gene expression profiles, which can be used to discover novel diagnostic and prognostic biomarkers. Here, we review clinical features of kidney cancer, the WHO classification system, and the growing role of molecular classification for diagnosis, prognosis, and therapy of this disease.

Nanomolecular histopathology for renal tumor classification

Renal tumors are classified into histopathologic subtypes based on light microscopy. Classification is important because subtypes have distinct genetic abnormalities and clinical behavior, yet is difficult because many cases have heterogeneous morphology. Thus, several molecular assays have been developed for tumor classification. Immunohistochemistry (IHC) permits correlation of molecular data with tissue morphology, but is difficult to quantify or perform in multiplex. Quantitative RT-PCR and gene expression microarrays are more quantitative, but lose morphologic information. We hypothesize that direct integration of histopathology with nanomolecular expression profiling will provide sensitive and specific data for renal tumor classification. Thus, we are developing novel IHC assays using antibodies conjugated to nanoparticle tags with surface-enhanced Raman scattering properties (SERS). Our preliminary data suggests that SERS-IHC can be performed using standard microscopic equipment, with potential for sensitive, quantitative multiplex assays on fixed tissues.

Endogenous stimulators and inhibitors of angiogenesis in gastrointestinal cancers: basic science to clinical application

Progression of cancer is dependent on acquisition of vascular networks within the tumor. Tumor angiogenesis is dependent on up-regulation of angiogenesis stimulators to overcome the endogenous anti-angiogenic barrier. Such disruption of angiogenesis balance to favor neovascularization is a key step for progression of tumor growth and metastasis. In this regard, the vascular basement membrane and the extracellular matrix have been found to be rich sources of angiogenesis stimulators and inhibitors that become bioavailable on proteolysis of the matrix by tumor microenvironment-related enzymes. In this review the subgroup of endogenous angiogenesis stimulators and inhibitors is discussed, and their mechanism of action during tumor angiogenesis is evaluated. The role in regulating tumor growth and the possibility of using them as prognostic markers for human gastrointestinal cancers is discussed. Furthermore, we specifically address the role of vascular endothelial growth factor in human gastrointestinal cancers and discuss the development and use of bevacizumab (Avastin; anti-vascular endothelial growth factor antibody [Genentech, CA]) in the treatment of colorectal and other gastrointestinal cancers.

Effect of thalidomide affecting VEGF secretion, cell migration, adhesion and capillary tube formation of human endothelial EA.hy 926 cells

Angiogenesis, new blood vessel formation, is a multistep process, precisely regulated by pro-angiogenic cytokines, which stimulate endothelial cells to migrate, proliferate and differentiate to form new capillary microvessels. Excessive vascular development and blood vessel remodeling appears in psoriasis, rheumatoid arthritis, diabetic retinopathy and solid tumors formation. Thalidomide [alpha-(N-phthalimido)-glutarimide] is known to be a potent inhibitor of angiogenesis, but the mechanism of its inhibitory action remains unclear. The aim of the study was to investigate the potential influence of thalidomide on the several steps of angiogenesis, using in vitro models. We have evaluated the effect of thalidomide on VEGF secretion, cell migration, adhesion as well as in capillary formation of human endothelial cell line EA.hy 926. Thalidomide at the concentrations of 0.01 microM and 10 microM inhibited VEGF secretion into supernatants, decreased the number of formed capillary tubes and increased cell adhesion to collagen. Administration of thalidomide at the concentration of 0.01 microM increased cell migration, while at 10 microM, it decreased cell migration. Thalidomide in concentrations from 0.1 microM to 10 microM did not change cell proliferation of 72-h cell cultures. We conclude that anti-angiogenic action of thalidomide is due to direct inhibitory action on VEGF secretion and capillary microvessel formation as well as immunomodulatory influence on EA.hy 926 cells migration and adhesion.

[Search for new anti-angiogenic agents with structural analogy with thalidomide]

Despite its teratogenic effects, thalidomide has been reintroduced in human anticancer treatment for its anti-angiogenic activity, especially observed in patients with multiple myeloma. Here, we report the synthesis of new analogues designed to increase the thalidomide anti-tumour properties. The anti-angiogenic activity of the compounds was tested on EA.hy 926 endothelial cell lines. In this model, that is easier to manipulate than HUVEC cells, thalidomide is active in a similar dose range as reported on HUVEC cells and one of our compounds is more efficient.