Conventional (clear cell) renal carcinoma metastases have greater bcl-2 expression than high-risk primary tumors

Runx2 silencing sensitized human renal cell carcinoma cells to ABT-737 apoptosis

The prognostic value of Runt-related transcription factor 2 (Runx2) and its involvement in cell growth and motility have been reported in patients diagnosed with renal cell carcinoma (RCC). Since Runx2 may have the potential to be a target for the purpose of antitumor intervention, there is an urgent need to gain insight into its oncogenic properties. Using human 786-O, Caki-1 and ACHN RCC cells as models, the silencing of cellular Runx2 expression brought about a reduction in cyclin D1 and β-catenin expression, cell growth and migration without any significant cell death. Runx2-silenced cells turned into apoptosis vulnerable in the presence of ABT-737, a BH3 mimetic Bcl-2 inhibitor. Data from biochemical and molecular studies have revealed a positive correlation between Runx2 expression and Akt phosphorylation, Mcl-1 expression, and fibronectin expression. Results of genetic silencing studies have indicated the potential involvement of Mcl-1 and fibronectin in the decision of RCC cell ABT-737 resistance and sensitivity. The regulatory roles of the PI3K/Akt axis in the expression of Mcl-1 and fibronectin were suggested by means of the results taken from experiments involving pharmacological study of the PI3K/Akt. Since overexpression and prognostic roles of Runx2, activated Akt, Mcl-1, fibronectin, cyclin D1, and β-catenin have been revealed in RCC, it is important to explore the precise mechanisms underlying Runx2 oncogenic effects. Although the linking details between Runx2 and PI3K/Akt have yet to be identified, our findings suggest that Mcl-1 and fibronectin are downstream effectors of Runx2 via a regulatory axis of the PI3K/Akt and their promotion of cell growth, migration, and ABT-737 resistance in RCC cells.

Bayesian Hierarchical Varying-sparsity Regression Models with Application to Cancer Proteogenomics

Identifying patient-specific prognostic biomarkers is of critical importance in developing personalized treatment for clinically and molecularly heterogeneous diseases such as cancer. In this article, we propose a novel regression framework, Bayesian hierarchical varying-sparsity regression (BEHAVIOR) models to select clinically relevant disease markers by integrating proteogenomic (proteomic+genomic) and clinical data. Our methods allow flexible modeling of protein-gene relationships as well as induces sparsity in both protein-gene and protein-survival relationships, to select ge-nomically driven prognostic protein markers at the patient-level. Simulation studies demonstrate the superior performance of BEHAVIOR against competing method in terms of both protein marker selection and survival prediction. We apply BEHAV-IOR to The Cancer Genome Atlas (TCGA) proteogenomic pan-cancer data and find several interesting prognostic proteins and pathways that are shared across multiple cancers and some that exclusively pertain to specific cancers.

Aspirin restores ABT-737-mediated apoptosis in human renal carcinoma cells

Aspirin is a novel chemopreventive agent against malignancy. However, outcomes of aspirin monotherapy of renal cell carcinoma (RCC) are inconsistent across studies. ABT-737, an BH3 mimetic inhibitor, is also a promising antitumor drug. Cancer cells including those from RCC, that have high levels of Mcl-1, are refractory to ABT-737-induced apoptosis. We here investigated how aspirin treatment modulates the ABT-737-induced apoptosis. Using the in vitro model of human 786-O cells, we showed that aspirin had sensitized cells to ABT-737 induced apoptosis. Such aspirin-induced changes of ABT-737 resistance was accompanied by a host of biochemical events like protein phosphatase 2A (PP2A) activation, AKT dephosphorylation, Mcl-1/FLICE inhibiting protein (FLIP)/XIAP downregulation, and Bax mitochondrial redistribution. The PP2A inhibitor, okadaic acid, was able to reverse the apirin-induced apoptotic changes. Apart from the aspirin treatment, Mcl-1 silencing also rendered cells vulnerable to ABT-737 induced apoptosis. Since PP2A, Akt, and Mcl-1 play critical roles in RCC malignancy and treatment resistance, our present study showed that aspirin, an alternative adjuvant agent, had recalled ABT-737 sensitivity in the RCC cells through processes involving the PP2A/Akt/Mcl-1 axis.

Are primary renal cell carcinoma and metastases of renal cell carcinoma the same cancer?

Metastasis is a process consisting of cells spreading from the primary site of the cancer to distant parts of the body. Our understanding of this spread is limited and molecular mechanisms causing particular characteristics of metastasis are still unknown. There is some evidence that primary renal cell carcinoma (RCC) and metastases of RCC exhibit molecular differences that may effect on the biological characteristics of the tumor. Some authors have detected differences in clear cell and nonclear cell component between these 2 groups of tumors. Investigators have also determined that primary RCC and metastases of RCC diverge in their range of renal-specific markers and other protein expression, gene expression pattern, and microRNA expression. There are also certain proteins that are variously expressed in primary RCCs and their metastases and have effect on clinical outcome, e.g., endothelin receptor type B, phos-S6, and CD44. However, further studies are needed on large cohorts of patients to identify differences representing promising targets for prognostic purposes predicting disease-free survival and the metastatic burden of a patient as well as their suitability as potential therapeutic targets. To sum up, in this review we have attempted to summarize studies connected with differences between primary RCC and its metastases and their influence on the biological characteristics of renal cancer.

The diagnostic accuracy of percutaneous renal needle core biopsy and its potential impact on the clinical management of renal cortical neoplasms

CONTEXT

While biopsies are now increasingly being performed for the diagnosis of renal cortical neoplasms, the influence of the rendered pathological diagnoses on the clinical management is only rarely documented.

OBJECTIVES

To report our experience with consecutively performed renal biopsies and the potential impact of the diagnosis on subsequent clinical management.

DESIGN

Material from needle biopsies performed consecutively at our institution between 2006 and 2011 was reviewed. The influence of the reported pathology results on the clinical management was determined from patient follow-up medical record review.

RESULTS

In total, 218 percutaneous biopsies for renal masses were performed during this period. Among them, 181 (83%) yielded neoplastic tissue, including 81 clear cell renal cell carcinomas, 29 low-grade oncocytic neoplasms, 7 papillary renal cell carcinomas, 5 clear cell papillary renal cell carcinomas, 5 angiomyolipomas, and 14 urothelial carcinomas. Fourteen additional cases (6%) contained lesional material from clinically known nonneoplastic processes, for a total diagnostic yield of 89%. Twenty-three (11%) were nonrepresentative of lesional tissue. In 10 of these, repeat biopsies or resections established the diagnosis of renal tumors. Biopsy diagnosis was confirmed in 29 of 30 cases (97%) on subsequent nephrectomy. Following the biopsy diagnosis, there were significant differences in the clinical management; overall, 79% of clear cell renal cell carcinomas received therapeutic interventions, and 17% were put on active surveillance. In contrast, 77% of the benign or low-grade lesions were put on active surveillance.

CONCLUSIONS

Accurate and specific diagnosis can be rendered on renal core biopsy in most renal tumors, and the biopsy diagnosis can have a definitive role in their clinical management.

Differential expression of prognostic proteomic markers in primary tumour, venous tumour thrombus and metastatic renal cell cancer tissue and correlation with patient outcome

Renal cell carcinoma (RCC) is the most deadly of urological malignancies. Metastatic disease affects one third of patients at diagnosis with a further third developing metastatic disease after extirpative surgery. Heterogeneity in the clinical course ensures predicting metastasis is notoriously difficult, despite the routine use of prognostic clinico-pathological parameters in risk stratification. With greater understanding of pathways involved in disease pathogenesis, a number of biomarkers have been shown to have prognostic significance, including Ki67, p53, vascular endothelial growth factor receptor 1 (VEGFR1) and ligand D (VEGFD), SNAIL and SLUG. Previous pathway analysis has been from study of the primary tumour, with little attention to the metastatic tumours which are the focus of targeted molecular therapies. As such, in this study a tissue microarray from 177 patients with primary renal tumour, renal vein tumour thrombus and/or RCC metastasis has been created and used with Automated Quantitative Analysis (AQUA) of immunofluorescence to study the prognostic significance of these markers in locally advanced and metastatic disease. Furthermore, this has allowed assessment of differential protein expression between the primary tumours, renal vein tumour thrombi and metastases. The results demonstrate that clinico-pathological parameters remain the most significant predictors of cancer specific survival; however, high VEGFR1 or VEGFD can predict poor cancer specific survival on univariate analysis for locally advanced and metastatic disease. There was significantly greater expression of Ki67, p53, VEGFR1, SLUG and SNAIL in the metastases compared with the primary tumours and renal vein tumour thrombi. With the exception of p53, these differences in protein expression have not been shown previously in RCC. This confirms the importance of proliferation, angiogenesis and epithelial to mesenchymal transition in the pathogenesis and metastasis of RCC. Importantly, this work highlights the need for further pathway analysis of metastatic tumours for overcoming drug resistance and developing new therapies.

Bcl-2 family of proteins as therapeutic targets in genitourinary neoplasms

INTRODUCTION

Overexpression of antiapoptotic B-cell lymphoma (Bcl-2) proteins confers the dysregulation of apoptosis and results in drug resistance in a variety of cancers, including those of the genitourinary tract. Inhibitors that target prosurvival Bcl-2 proteins are in preclinical and clinical development. The objective of this review is to assess the involvement of Bcl-2 proteins as well as the preclinical and clinical activity of Bcl-2 inhibitors under evaluation for genitourinary neoplasms.

MATERIALS AND METHODS

PubMed was used with both medical subject heading terms and free search to identify the relevant literature. Information on clinical trials was obtained using http://Clincaltrials.gov, EU Clinical Trials Register, and meeting abstracts of the American Society of Clinical Oncology.

RESULTS

To date, 2 Bcl-2 inhibitors have been evaluated in clinical trials for genitourinary tumors (oblimersen and AT-101 (R-(-)-gossypol)). Both agents demonstrated some success in early stages of development, but their clinical activity did not meet expectations. Preclinical studies are under way for other Bcl-2 inhibitors including ABT-737, HA14-1, and Bcl-2 homology 3 inhibitors.

CONCLUSION

Antiapoptotic Bcl-2 proteins are potential molecular targets in genitourinary cancers. Bcl-2 inhibitors might be effective as single agents or in combination with conventional therapies. However, the biology of the Bcl-2 family in genitourinary cancers remains poorly understood and robust preclinical studies are needed to inform clinical development. Such studies should aim to identify: (1) pharmacodynamic markers that could help guide patient selection for treatment with Bcl-2 inhibitors, and (2) optimal combinations of Bcl-2 inhibitors with other anticancer agents for future clinical investigation.

Multiple biomarker tissue arrays: A computational approach to identifying protein-protein interactions in the EGFR/ERK signalling pathway

Background

Many studies have demonstrated genetic and environmental factors that lead to renal cell carcinoma (RCC) and that occur during a protracted period of tumourigenesis. It appears suitable to identify and characterise potential molecular markers that appear during tumourigenesis and that might provide rapid and effective possibilities for the early detection of RCC. EGFR activation induces cell cycle progression, inhibition of apoptosis and angiogenesis, promotion of invasion/metastasis, and other tumour promoting activities. Over-expression of EGFR is thought to play an important role in tumour initiation and progression of RCC because up-regulation of EGFR has been associated with high grade cancers and a worse prognosis.

Methods

Characterisation of the protein profile interacting with EGFR was performed using the following: an immunohistochemical (IHC) study of EGFR, a comprehensive computational study of EGFR protein-protein interactions, an analysis correlating the expression levels of EGFR with other significant markers in the tumourigenicity of RCC, and finally, an analysis of the utility of EGFR for prognosis in a cohort of patients with renal cell carcinoma.

Results

The cases that showed a higher level of this protein fell within the clear cell histological subtype (p = 0.001). The EGFR significance statistic was found with respect to a worse prognosis. In vivo significant correlations were found with PDGFR-β, Flk-1, Hif1-α, proteins related to differentiation (such as DLL3 and DLL4 ligands), and certain metabolic proteins such as Glut5. In silico significant associations gave us a panel of 32 EGFR-interacting proteins (EIP) using the APID and STRING databases.

Conclusions

This work summarises the multifaceted role of EGFR in the pathology of RCC, and it identifies EIPs that could help to provide mechanistic explanations for the different behaviours observed in tumours.

Prognostic markers in renal cell carcinoma: A focus on the 'mammalian target of rapamycin' pathway

Objectives

Increased knowledge about the molecular pathways involved in tumorigenesis has led to the discovery of new prognostic molecular markers and development of novel targeted therapies for renal cell carcinoma (RCC). In this review we describe the prognostic markers of RCC and highlight the areas of recent discovery with a focus on the mammalian target of rapamycin (mTOR) pathway.

Methods

We reviewed previous reports, using PubMed with the search terms ‘renal cell carcinoma’, ‘molecular markers’, ‘prognosis’, ‘outcomes’ and ‘mammalian target of rapamycin pathway’ published in the last two decades. We created a library of 100 references and focused on presenting the recent advances in the field.

Results

Growing evidence suggests that mTOR deregulation is associated with many types of human cancer, including RCC. Consequently, temsirolimus and everolimus, which target mTOR, are approved for treating advanced RCC. There is a demand to integrate clinical, pathological and molecular markers into accurate prognostic models to provide patients with the most personalised cancer care possible.

Conclusions

The mTOR pathway is highly implicated in RCC tumorigenesis and progression, and its constituents might represent a promising prognostic tool and target for treating RCC. Combining newly discovered molecular markers with classic clinicopathological prognostics might potentially improve the management of RCC.

Xp11 translocation renal cell carcinoma (RCC): extended immunohistochemical profile emphasizing novel RCC markers

Xp11 translocation renal cell carcinoma (RCC) harbor various TFE3 gene fusions, and are known to underexpress epithelial immunohistochemical (IHC) markers such as cytokeratin and EMA relative to usual adult type RCC; however, their profile in reference to other IHC markers that are differentially expressed in other subtypes of RCC has not been systematically assessed. Few therapeutic targets have been identified in these aggressive cancers. We created 2 tissue microarrays (TMA) containing five 1.4-mm cores from each of 21 Xp11 translocation RCC (all confirmed by TFE3 IHC, 6 further confirmed by genetics), 7 clear cell RCC (CCRCC), and 6 papillary RCC (PRCC). These TMA were labeled for a panel of IHC markers. In contrast to earlier published data, Xp11 translocation RCC frequently expressed renal transcription factors PAX8 (16/21 cases) and PAX2 (14/21 cases), whereas only 1 of 21 cases focally expressed MiTF and only 5 of 21 overexpressed p21. Although experimental data suggest otherwise, Xp11 translocation RCC did not express WT-1 (0/21 cases). Although 24% of Xp11 translocation RCC expressed HIF-1alpha (like CCRCC), unlike CCRCC CA IX expression was characteristically only focal (mean 6% cell labeling) in Xp11 translocation RCC. Other markers preferentially expressed in CCRCC or PRCC, such as HIG-2, claudin 7, and EpCAM, yielded inconsistent results in Xp11 translocation RCC. Xp11 translocation RCC infrequently expressed Ksp-cadherin (3/21 cases) and c-kit (0/21 cases), markers frequently expressed in chromophobe RCC. Using an H-score that is the product of intensity and percentage labeling, Xp11 translocation RCC expressed higher levels of phosphorylated S6, a measure of mTOR pathway activation (mean H score=88), than did CCRCC (mean H score=54) or PRCC (mean H score=44). In conclusion, in contrast to prior reports, Xp11 translocation RCC usually express PAX2 and PAX8 but do not usually express MiTF. Although they may express HIF-1alpha, they only focally express the downstream target CA IX. They inconsistently express markers associated with other RCC subtypes, further highlighting the lack of specificity of the latter markers. TFE3 and Cathepsin K remain the most sensitive and specific markers of these neoplasms. Elevated expression of phosphorylated S6 in Xp11 translocation RCC suggests the mTOR pathway as an attractive potential therapeutic target for these neoplasms.

Inhibition of nuclear factor kappa B transcription activity drives a synergistic effect of pyrrolidine dithiocarbamate and cisplatin for treatment of renal cell carcinoma

One of the impeding factors in the effective treatment of metastatic renal cell carcinoma (RCC) is their intrinsic and acquired resistance to chemotherapeutics. Many studies have shown that drug resistance, at least in part, is mediated by the upregulation of anti-apoptotic (Bcl-2) and multidrug resistance molecules (MDR-1 and MRP-1) by the transcription factor nuclear factor kappa B (NF-kappaB). Combining NF-kappaB inhibitors with conventional chemotherapeutics could overcome resistance of cancer cells. In this study, we examined the synergistic effect of pyrrolidine dithiocarbamate (PDTC), a NF-kappaB inhibitor, and cisplatin, on two human metastatic RCC cell lines ACHN and SN12K1. Individual non-toxic concentrations of PDTC and cisplatin, when combined, synergistically induced a significant increase in apoptosis of the two RCC cell lines. In ACHN cells, the groups with nuclear translocation of NF-kappaB showed resistance to apoptosis, but in SN12K1 cells, the groups with NF-kappaB translocation were susceptible to apoptosis. The combination treatment significantly decreased the transcription activity of all NF-kappaB subunits in both cell lines. Anti-apoptotic proteins Bcl-2 and Bcl-(XL) were significantly decreased in the combination therapy group of both cell lines, but MDR-1 was decreased only in the ACHN cells. No changes in MRP-1 were observed in any of the treatment groups. The results demonstrate the potential of PDTC to be an adjunct therapeutic agent. The major mechanism of the synergistic effect appears to be mediated by the inhibition of transcription activity of NF-kappaB rather than its expression, and the resultant decrease in the anti-apoptotic proteins Bcl-2 and Bcl-(XL).

Inhibition of nuclear factor kappa B attenuates tumour progression in an animal model of renal cell carcinoma

BACKGROUND

Renal cell carcinoma (RCC) is a highly metastatic and lethal disease with few efficacious treatments. Many studies have shown that the ubiquitous transcription factor nuclear factor kappa B (NF-kappaB) plays a key role in the development and progression of many cancers including RCC. The aim of this investigation was to evaluate the anti-cancer effect of pyrrolidine dithiocarbamate (PDTC), a NF-kappaB inhibitor, in a murine xenograft model of RCC.

METHODS

The metastatic human RCC cell line, SN12K1, was inoculated into the left kidneys of severe combined immunodeficiency mice and the effect of semi-continuous PDTC treatment (50 mg/kg) on RCC growth analysed 5 weeks later. The analyses carried out in three groups (no treatment, RCC alone and RCC + PDTC) at 5 weeks were: renal weight, protein expression by immunohistochemistry and Western immunoblot, apoptosis (TdT-mediated nick end labelling and morphology) and mitosis (morphology).

RESULTS

PDTC significantly decreased RCC growth and the expression of NF-kappaB subunits (p50, p52, c-Rel and RelB), upstream IKK-beta and IKK-gamma, but did not induce any changes in the expression of IkappaB-alpha and IkappaB-beta. RCC growth was associated with a significant decrease in the expression of the anti-apoptotic proteins Bcl-2 and Bcl-(XL) and increase in pro-apoptotic Bax, all of which were reversed by PDTC. Cell proliferation was significantly reduced by PDTC.

CONCLUSION

The results demonstrate the potential anti-cancer benefits of treating NF-kappaB positive RCCs with NF-kappaB inhibitors like PDTC.

Diagnostic and prognostic molecular markers in renal cell carcinoma

PURPOSE

We reviewed the contemporary literature on molecular biomarkers in renal cell carcinoma and their prognostic significance.

MATERIALS AND METHODS

Articles published during 1981 to 2007 in English on renal cell carcinoma were surveyed using the MEDLINE/PubMed database. The subject headings included were genetics, biomarkers, prognosis and risk models of renal cell carcinoma. We present a synthesis of currently known renal cell carcinoma biomarkers at various stages of development and their clinical significance, and prognostic nomograms incorporating biomarkers.

RESULTS

The beneficiary role of biomarkers in renal cell carcinoma is challenged by the relatively low prevalence of the disease. Even if a biomarker for renal cell carcinoma had 100% sensitivity and 99.4% specificity, the positive predictive value of the marker in men older than 65 years would be only 10%. Several biomarkers are being investigated in renal cell carcinoma, of which many relate to pathogenic molecular changes that are currently therapeutic targets. Carbonic anhydrase IX is a von Hippel-Lindau mediated enzyme that is expressed in most renal cell carcinoma cases. High (greater than 85%) expression of this marker indicates favorable prognosis and may predict the response to interleukin-2 therapy. B7-H1 expression in renal cell carcinoma cells/lymphocytes may indicate worse survival, possibly through impaired host antitumor immunity. Prognostic nomograms incorporating clinical variables and molecular markers to refine the prediction of treatment outcomes are in active development and await prospective clinical validation.

CONCLUSIONS

Several renal cell carcinoma molecular markers appear promising to refine the prognosis and prediction of localized, advanced or metastatic renal cell carcinoma. Currently carbonic anhydrase IX is the best studied and promising marker. Prospective, multicenter clinical validation aimed at the practical clinical usefulness of renal cell carcinoma biomarkers is warranted.

Bcl-2 protein and DNA ploidy in renal cell carcinoma: do they affect patient prognosis?

AIM

The aim of the present study was to correlate bcl-2 protein expression and DNA-ploidy status with established prognostic parameters in renal cell carcinoma (RCC) and to examine their impact on disease progression and patient survival.

METHODS

Both parameters were prospectively measured in 50 consecutive radical nephrectomy specimens using flow cytometry. They were correlated with the tumor grade, stage and histological type. Kaplan-Meier survival analysis for all parameters was performed.

RESULTS

Bcl-2 protein expression was higher in RCC compared to normal renal tissue (P < 0.0001). Aneuploid tumors had higher bcl-2 expression compared to diploid tumors (P = 0.015). Bcl-2 expression and DNA content were not correlated with tumor histological types (P = 0.277/P = 0.419), grades (P = 0.690/P = 0.449), T categories (P = 0.637/P = 0.585) or stages (P = 0.726/P = 0.800). Median follow-up time was 46 months (range, 5-84) with a mean overall survival of 61.8 months (95% confidence interval, 53.7-69.9). Tumor stage was the only statistically important prognostic factor (P = 0.0045).

CONCLUSION

Although Bcl-2 expression was correlated with tumor DNA content, the prognostic value of these two parameters following radical nephrectomy was not established.

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.

Cyclooxygenase-2 regulates the degree of apoptosis by modulating bcl-2 protein in pleomorphic adenoma and mucoepidermoid carcinoma of the parotid gland

CONCLUSION

These results suggest that COX-2 and bcl-2 protein were overexpressed and that apoptosis was reduced in MEC compared to PMA, and that COX-2 may regulate the degree of apoptosis by modulating bcl-2 protein in PMA and MEC.

OBJECTIVE

Cyclooxygenase (COX)-2 plays a crucial role in tumorigenesis and overexpression of COX-2 in vitro accompanied by overexpression of bcl-2 protein has been shown to reduce apoptosis. The purpose of this study was to verify that COX-2 regulates the degree of apoptosis by modulating bcl-2 protein in benign and malignant parotid gland tumors. : We examined archival formalin-fixed, paraffin-embedded tissue sections of 10 pleomorphic adenomas (PMAs) and 10 mucoepidermoid carcinomas (MECs) by immunostaining with anti-COX-2, anti-bcl-2 and anti-single-stranded DNA (ssDNA) antibodies. Labeling indices of the three antibodies were calculated using computer-assisted image analysis.

RESULTS

Labeling indices (mean+/-SD) of anti-COX-2 antibody in PMA and MEC were 2.05+/-1.30 and 11.2+/-2.95, respectively (p < 0.001), those of anti-bcl-2 antibody were 2.00+/-1.28 and 9.68+/-4.05, respectively (p < 0.001) and those of anti-ssDNA antibody were 8.06+/-2.54 and 2.08+/-1.47; respectively (p <0.001). Correlation coefficients between the labeling indices of anti-COX-2 antibody and anti-bcl-2 antibody, anti-bcl-2 antibody and anti-ssDNA antibody and anti-COX-2 antibody and anti-ssDNA antibody were 0.88, -0.75 and -0.76, respectively (p <0.001).

Inhibition of bcl-2 enhances the efficacy of chemotherapy in renal cell carcinoma

OBJECTIVES

Renal cell cancer (RCC) is highly resistant to chemotherapy. Increased expression of the antiapoptotic gene bcl-2 in tumors is known to be associated with poor responses to systemic treatment of cancer. Down-regulation of bcl-2 expression using antisense oligonucleotides (asON) has been shown to increase chemosensitivity in clinical phase I-III studies with various cancers. However, no studies on the efficacy of this approach in RCC have been reported so far. This study aimed to evaluate whether bcl-2 asON could enhance efficacy of chemotherapy in human RCC.

MATERIAL AND METHODS

Expression of bcl-2 mRNA and protein was analyzed in different RCC cell lines by RT-PCR and Western blot. Cells with high or low bcl-2 mRNA and protein expression were treated with different concentrations of bcl-2 asON in combination with cisplatin. AsON-induced down-regulation of bcl-2 mRNA and protein was documented by RT-PCR and Western blot. Treatment effects on cell viability were analyzed by colorimetric tetrazolium (MTT) assay. Immunohistochemical staining of M30-positive cells was performed for quantification of apoptotic cells.

RESULTS

Transfection of high bcl-2 expressing cells with bcl-2 asON alone induced no reduction of cell viability at a concentration range from 100-1000 nM. In combination therapy, pretreatment with asON significantly enhanced MTT reduction after cisplatin treatment. IC50 concentrations of cisplatin were 1 microg/ml with and 2.7 microg/ml without prior incubation. The marked reduction of cell viability correlated with an 8-fold increase of apoptotic cells after combination treatment. Only a minor increase of cisplatin effectivity was noted after asON preincubation of cells with lower bcl-2 expression.

CONCLUSIONS

The combination of cisplatin and bcl-2 antisense ON exerts significantly greater effects on cell viability and apoptosis than either agent used alone on human RCC cells. These data indicate that inhibition of bcl-2 expression may be an attractive therapeutic strategy in RCC tumors with high bcl-2 expression.

Downregulation of Bcl-2 sensitises interferon-resistant renal cancer cells to Fas

Interferon α (IFNα) is used to treat patients with advanced renal cell carcinoma (RCC) despite limited clinical benefit. IFNα can induce Fas receptor-mediated apoptosis by direct activation of pro-caspase-8 followed by activation of caspase-3. Alternative, indirect activation of caspase-3 via mitochondrial release of cytochrome c can occur and may explain the rescue from Fas-activated cell death by the antiapoptotic members of the Bcl-2 family. In this study, we examined G3139, a novel antisense compound targeting Bcl-2, in combination with IFNα. Human RCC lines (SK-RC-44 and SK-RC-07) were treated with IFNα, G3139 or a combination of the two. Fas-mediated cytotoxicity was induced by anti-Fas mAb, CH11. An analysis of Bcl-2, Fas and the cleavage of PARP was performed. IFNα induced Fas and Bcl-2 in SK-RC-44 and SK-RC-07. IFNα sensitised SK-RC-44 to anti-Fas and induced PARP cleavage confirming that IFNα has a cytotoxic effect on RCC lines by induction of the Fas antigen. Cytotoxicity was not evident in SK-RC-07 cells treated with IFNα. G3139 induced a specific downregulation of Bcl-2 in SK-RC-07 cells, which were then sensitised to anti-Fas after treatment with IFNα. Taken together, these results suggest that Fas-dependent pathways as well as alternative pathways, which can be inhibited by Bcl-2, exist in renal cell carcinoma. G3139 in combination with IFNα is a potential therapy in patients with metastatic renal cell carcinoma.

Evaluation of P-glycoprotein, HER-2/ErbB-2, p53, and Bcl-2 in primary tumor and metachronous lung metastases in patients with high-grade osteosarcoma

BACKGROUND

Investigation of the relation between primary tumor and metastatic disease is necessary for the identification of predictive factors for postrecurrence survival (PRS) in patients with recurrent osteosarcoma.

METHODS

Cellular levels of P-glycoprotein, ErbB-2, p53, and Bcl-2 expression were evaluated in primary tumor biopsy and metachronous pulmonary metastasis specimens from 19 patients with high-grade osteosarcoma. Results were analyzed for differences between primary tumor and pulmonary metastases and for correlations between expression patterns and survival.

RESULTS

Positive staining in lung metastases was noted in 68%, 53%, 32%, and 84% of patients for P-glycoprotein, ErbB-2, p53, and Bcl-2, respectively. These percentages were higher than those observed in primary tumor specimens for all genetic markers evaluated, with a significant difference in the percentage of patients with positive staining for P-glycoprotein (68% vs. 32%; P = 0.05) and a near-significant difference in the percentage of patients with positive staining for Bcl-2 (84% vs. 53%; P = 0.08). Patients with ErbB-2 expression in the primary tumor were more likely to have multiple metastases and shorter recurrence-free intervals compared with patients in whom ErbB-2 expression was not observed, whereas differences in P-glycoprotein, p53, and Bcl-2 expression were not related to differences in metastatic pattern. PRS was influenced by p53 expression levels in pulmonary metastases, with patients who had negative staining for p53 having a significantly better PRS rate relative to patients with positive staining for p53 (3-year PRS rate: p53-negative, 64%; p53-positive, 17%; P = 0.008).

CONCLUSIONS

In the current study of patients with high-grade osteosarcoma, most patients exhibited increased cellular expression of P-glycoprotein, ErbB-2, and Bcl-2 in recurrent pulmonary metastases compared with primary tumor. Further studies aimed at investigating the relation between altered p53 expression in lung metastases and postrecurrence survival are recommended.