Von Hippel-Lindau Disease Tumor Suppressor Research Articles

High VHL Expression Reverses Warburg Phenotype and Enhances Immunogenicity in Kidney Tumor Cells

Clear cell renal cell carcinoma (ccRCC) is a frequently occurring renal cancer. The Von Hippel-Lindau disease tumor suppressor VHL, a known tumor suppressor gene, is frequently mutated in about 50% of patients with ccRCC. However, it is unclear whether VHL influences the progression of ccRCC tumors expressing wild-type VHL. In the present study, we found that higher expression of VHL was correlated with the better disease-free survival (DFS) in ccRCC patients using The Cancer Genome Atlas (TCGA) datasets. We revealed that VHL overexpression in ccRCC cells inhibited epithelial-mesenchymal transition (EMT), sterol regulatory element-binding protein 1 (SREBP1)-regulated triglyceride synthesis, and cell proliferation. Proteomic analysis provided us a global view that VHL regulated four biological processes, including metabolism, immune regulation, apoptosis, and cell movement. Importantly, we found that VHL overexpression led to up-regulated expression of proteins associated with antigen processing and interferon-responsive proteins, thus rendering ccRCC cells more sensitive to interferon treatment. We defined an interferon-responsive signature (IRS) composed of ten interferon-responsive proteins, whose mRNA expression levels were positively correlated with DFS in ccRCC patients. Taken together, our results propose that the subset of ccRCC patients with high VHL expression benefit from immunotherapy.

Kinetic Detection of E3:PROTAC:Target Ternary Complexes Using NanoBRET Technology in Live Cells.

Heterobifunctional small-molecule degraders known as Proteolysis Targeting Chimeras (PROTACs) serve as a chemical bridge bringing into direct association a target protein with an active E3 ligase complex, called the ternary complex, to facilitate targeted protein degradation. This ternary complex formation is the first key mechanistic step in a cascade of events that results in ubiquitination and subsequent degradation of the target protein via the ubiquitin-proteasome pathway. The ternary complex, however, is a nonnative cellular complex; therefore, PROTAC compound design has many challenges to overcome to ensure successful formation, including achieving structural and electrostatic favorability among target and ligase. Due to these challenges, finding successful PROTACs typically requires testing of extensive libraries of heterobifunctional compounds with varying linkers and E3 handles. As PROTAC ternary complex formation is also critically dependent on cellular context, live cell assays and technologies for rapid and robust screening are highly enabling for triaging of early stage compounds. Here, we present cellular assays utilizing NanoBRET technology for the study of ternary complexes, showing examples with two most popular PROTAC E3 ligase components, VHL (von Hippel-Lindau disease tumor suppressor) and CRBN (Cereblon). These assays can be run in either endpoint or real-time kinetic formats, are compatible with high-throughput workflows, and provide insight into how altering the PROTAC chemical composition affects the formation and stability of the ternary complex in live cells.

High kinesin family member 11 expression predicts poor prognosis in patients with clear cell renal cell carcinoma

AimsKinesin family member 11 (Kif11) is a member of the kinesin family motor proteins, which is associated with spindle formation and tumour genesis. In this study, we investigated the relationship...

Epigenetics in renal cell cancer: mechanisms and clinical applications.

Renal cell carcinoma (RCC) is characterized by an infrequent number of somatic mutations. By contrast, epigenetic aberrations are commonly found in RCC, indicating that epigenetic reprogramming is an important event in RCC development. Epigenetic alterations comprise several different aberrations, such as changes in histone modifications, DNA methylation, and microRNA levels, and occur in the most important signalling pathways in RCC, such as the von Hippel-Lindau disease tumour suppressor (VHL)-hypoxia-inducible factor (HIF) pathway, the WNT-β-catenin pathway, and pathways involved in epithelial-mesenchymal transition. Owing to their involvement in these pathways and frequent occurrence in RCC, epigenetic alterations are regarded as potential biomarkers for the early detection of disease and for prediction of prognosis and treatment response. In addition, most of these alterations are potentially reversible, so they also provide new targets for therapy. At the moment, epigenetic biomarkers for RCC are not being used in clinical practice, but targeted epigenetic therapies are under investigation. Understanding the extent of epigenetic changes occurring in RCC and the mechanisms by which they influence disease progression and treatment response, as well as knowledge of current research on biomarkers and treatments, is crucial to successful clinical translation of epigenetics in RCC.

Genetics and molecular pathogenesis of pheochromocytoma and paraganglioma

Although most pheochromocytomas (PCCs) and paragangliomas (PGLs) are sporadic, molecular genetic medicine has revealed that a considerable number of patients with apparently sporadic PCC actually have a genetic predisposition to the development of these tumors. After decades of intensive research, several genes are now known to play an important role in the pathogenesis of PCC. At present, these are RET proto-oncogene, von Hippel-Lindau disease tumor suppressor gene (VHL), neurofibromatosis type 1 tumor suppressor gene (NF1), genes encoding the succinate dehydrogenase (SDH) complex subunits SDHB, SDHC, and SDHD, but also SDHA, the gene encoding the enzyme responsible for the flavination of SDHA (SDHAF2 or hSDH5), and the newly described TMEM127 and MAX tumor suppressor genes. In addition to these ten PCC susceptibility genes, two other genes, KIF1B and PHD2, have also been associated with PCC. Studying the pathogenesis and the molecular correlation of these mutations has revealed the existence of two main transcription signatures: a pseudohypoxic cluster (VHL and SDH mutations) and a cluster rich in kinase receptor signaling and their downstream pathways (RET, NF1, TMEM127, and MAX mutations). However, the general mechanism in the pathogenesis of a syndrome does not entirely apply in the particular pathogenesis of PCC as a manifestation of that syndrome. A better understanding of the complexity and high genetic diversity of PCC and PGL may lead to more efficient diagnosis and management of the disease.

Proteostasis Modulators Prolong Missense VHL Protein Activity and Halt Tumor Progression

Although missense mutations of the von Hippel-Lindau disease (VHL) gene are the most common germline mutation underlying this heritable cancer syndrome, the mechanism of tumorigenesis is unknown. We found a quantitative reduction of missense mutant VHL protein (pVHL) in tumors associated with physiologic mRNA expression. Although mutant pVHL is unstable and degraded contemporarily with translation, it retains its E3 ligase function, including hypoxia-inducible factor degradation. The premature pVHL degradation is due to misfolding and imbalance of chaperonin binding. Histone deacetylase inhibitors (HDACIs) can modulate this pathway by inhibiting the HDAC-Hsp90 chaperone axis, stabilizing pVHL, and restoring activity comparable to wild-type protein, both in vitro and in animal models. Furthermore, HDACI-mediated stabilization of missense pVHL significantly attenuates the growth of 786-O rodent tumor model. These findings provide direct biological insight into VHL-associated tumors and elucidate a treatment paradigm for VHL.

Tivozanib: Practical implications for renal cell carcinoma and other solid tumors

Tivozanib is a recently developed, small-molecule tyrosine kinase inhibitor with specific affinity for the vascular endothelial growth factor receptor (VEGFR) family of kinases. Given known relevance of VHL (Von Hippel-Lindau disease tumor suppressor) deregulation in the clear cell variant of renal cell carcinoma, renal cell carcinoma remains an area of interest and subject of recent registration trials with this approach. TIVO-1, a phase III study evaluating tivozanib versus sorafenib in the first-line setting, met its primary endpoint of progression-free survival (11.9 months for tivozanib vs. 9.1 months for sorafenib), with a manageable toxicity profile, leading to formal consideration of regulatory approval in this setting. This review focuses on the preclinical development, pharmacokinetics and early clinical activity of tivozanib in renal cell carcinoma and other solid tumors.

IJU this issue

Mototsugu Oya M.D., Associate Editor In this issue, I would like to focus on “degenerative” and “regenerative” medicine. The degenerative issue is renal cell carcimoma (RCC) arising in end-stage kidneys. Whether RCC arising in patients under hemodialysis (HD) is the same as or different from non-HD RCC in terms of oncogenesis is an important issue to be resolved. The most important molecule related to RCC oncogenesis is von Hippel-Lindau disease tumor suppressor gene. The mutation of the gene is observed both in sporadic non-HD patients and HD patients. In contrast, in pathological aspects, RCC arising in HD patients occasionally have different types of cancer tissues (described by Tickoo SK et al. cited #25 in Takagi's paper). This suggests a distinctly different oncogenic pathway. The most different feature, I believe, is that HD-related RCC are multifocal in contrast to the non-HD, which is single (unifocal). Multifocal tumors can arise in susceptible, pre-oncogenic tissues. For example, liver cancer arises from hepatitis virus-infected tissues that are susceptible to cancer. Takagi et al. described the clinical characteristics of RCC in HD patients in a single institution. They showed that bilateral occurrence did not influence the likelihood of death from cancer, suggesting de novo primary events rather than the metastases of the contralateral primary. Interestingly, a longer duration before surgery was an unfavorable prognosis. This suggests that the accumulation of molecular alteration in end-stage kidneys is related to progression of the cancer as well as the initiation. Molecular pathogenesis needs to be elucidated in this malignant phenotype of long HD-associated RCC. Venous extension or tumor thrombus is a feature of RCC that is rarely observed in other cancers. The 7th edition of UICC changed the T3 classification. The cephalad extent of the tumor was divided into three parts, namely, renal vein, inferior vena cava (IVC) below the diaphragm and IVC above the diaphragm, and assigned T3a, T3b and T3c. Nagata et al. assessed the revision of UICC using the clinical data in their institution retrospectively. Their Kaplan–Meier curves were clearly separated accordingly. They concluded that the new classification could be valid in Japan. T category in RCC is complex, as compared with other cancers. For example, T factor in bladder cancer is simply the extent of the invasion. In determining the T of RCC, tumor size, perinephric invasion, adrenal invasion and venous involvement should be evaluated. The 7th edition of UICC is not perfect. Based on accumulating publications, T factor might be changed in the future. Regenerative medicine is one of the main topics at present. Obinata et al. used a unique cell transplantation system named adipocyte-derived dedifferentiated fat (DFAT) cells to treat stress urinary incontinence (SUI) in a rat model. DFAT cells are easily isolated from a small amount (approximately 1 g) of subcutaneous adipose tissue and differentiated to smooth muscle-like cells by adding transforming growth factor-β1. A cross-section of the urethra showed a marked difference in terms of the thickness of the muscle layers in the DFAT-injected rats. As mentioned in the Editorial Comment by Pastor-Navarro, this injured model is not a permanent model. SUI is a permanent injury as a result of labor during childbirth. She mentioned a need for a permanent injury model to validate the results. I believe DFAT is easy and can be applicable to clinical use. However, several issues should be clarified. How and how long are the dedifferentiated muscle-like cells maintained in the tissues? How is the injected DFAT distributed and how about the injured muscle cells? An easy method that is replicable by other researchers can survive in regenerative medicine. To explore an easy way is a short cut to clinical use. None declared.

Preimplantation genetic diagnosis of Von Hippel-Lindau disease cancer syndrome by combined mutation and segregation analysis

Von Hippel-Lindau (VHL) disease is an autosomal dominant cancer syndrome, associated with the development of tumors and cysts in multiple organ systems, whose expression and age of onset are highly variable. The VHL disease tumor suppressor gene (VHL) maps to 3p25-p26 and mutations ranging from a single base change to large deletions have been detected in patients with VHL disease. We developed a single cell PCR protocol for preimplantation genetic diagnosis (PGD) of VHL disease to select unaffected embryos on the basis of the detection of the specific mutation and segregation analysis of polymorphic linked markers. Multiplex-nested PCR using single buccal cells of an affected individual were performed in order to test the accuracy and reliability of this single-cell protocol. For each locus tested, amplification efficiency was 83% to 87% and allelic drop-out rates ranged from 12% to 8%. Three VHL disease PGD cycles were performed on cells from a couple with paternal transmission of a 436delC mutation in exon 2 of the VHL gene, leading to the identification of three unaffected embryos. Independent of the mutation present, this general PGD protocol for the diagnosis of VHL disease can be used in families informative for either the D3S1038 or D3S1317 microsatellite markers.

The Tumor Suppressor von Hippel-Lindau Gene Product and Metastasis: New Thoughts on an Old Molecule

In this issue of The American Journal of Pathology, long-time von Hippel-Lindau (VHL) pioneer William G. Kaelin with Nakamura and colleagues1 demonstrates that cells lacking wild-type VHL are defective in the expression and secretion of the glycoprotein clusterin. This phenomenon was observed in cells capable of ubiquitylating hypoxia-inducible factor (HIF) and possessing Type 2C VHL mutants. The authors also found that pVHL-defective renal carcinoma cells overexpress insulin-like growth factor binding protein-3 (IGBP3) and plasminogen activator inhibitor type-1 in a HIF-dependent manner. Previous reports have described pVHL modulating other genes in a HIF-independent manner to promote its tumor suppressor function; however, the overexpression of clusterin by pVHL raises several questions and requires further discussion.

VHL tumor suppressor gene alterations associated with good prognosis in sporadic clear-cell renal carcinoma.

Somatic alteration of the von Hippel-Lindau disease tumor suppressor gene (VHL) is one of the most common genetic changes observed in the sporadic, clear-cell subtype of renal cell carcinoma (RCC). However, the prognostic utility of VHL mutations has not been examined. The purpose of this study was to explore the association between VHL mutations and the risk of death from sporadic clear-cell RCC. A total of 187 Japanese patients with clear-cell RCC who underwent nephrectomy from October 1986 through December 1995 were examined for somatic VHL gene alteration. Clinicopathologic and survival data were also collected. Kaplan-Meier analyses and Cox proportional hazards models were used to explore associations. All statistical tests were two-sided. A VHL alteration (mutation or hypermethylation) was detected in 108 RCC tumor samples: intragenic mutations in 98 (52%) and hypermethylation in 10 (5.3%). VHL alterations were strongly associated with better cancer-free survival and cancer-specific survival for the 134 patients with stage I-III clear-cell RCC treated by radical nephrectomy (log-rank P =.024 and.023, respectively). These associations were more statistically significant among patients with relatively advanced disease (stage III [P =.014 and.010, respectively] or stage II + III [P =.002 and.009]) or higher grade tumors (G3 or higher [P =.013 and.032] or G2 or higher [P =.013 and.018]) and among patients who presented with symptoms (P =.005 and.012). VHL alterations remained an independent prognostic factor for patients with stage I-III tumors after adjustment for sex, age, stage, grading, and symptomatic presentation. VHL alterations were not associated with cancer-specific survival for the 53 patients with stage IV tumors treated with palliative or adjunctive nephrectomy (log-rank P =.760). The VHL alteration status may provide useful prognostic information, as a biomolecular marker, for patients with stage I-III clear-cell RCC who have undergone nephrectomy.

Germline mutations detected in the von Hippel-Lindau disease tumor suppressor gene by southern blot and direct genomic DNA sequencing

Germline mutations detected in the von Hippel Lindau diseasetumor suppressor gene by southern blot and direct genomic DNA sequencing

Alterations of tumor suppressor genes and the H-ras oncogene in oral squamous cell carcinoma.

The frequencies of mutations in the adenomatous polyposis coli (APC). p53, and p16 (MTS1; multiple tumor suppressor 1/CDK4I; cyclin-dependent kinase 4 inhibitor) tumor suppressor genes were investigated in 23 oral squamous cell carcinomas (SCCs). Loss of heterozygosity (LOH) at the retinoblastoma (Rb) gene locus and on chromosomes 3p (VHL; von Hippel-Lindau disease tumor suppressor gene locus), 5q (APC) and 9p (p16), and H-ras oncogene mutations were also studied in the same samples. Techniques employed were polymerase chain reaction single-strand conformation polymorphism (PCR-SSCP), DNA sequencing and PCR-microsatellite analyses. Mutations of the p53 gene were detected in 26% (6/23) of the tumor specimens. APC and p16 were not mutated in any of the 23 oral SCCs studied. LOH was detected in 17% (2/12 informative cases) at the Rb, in 33% (4/12) on 3p, in 17% (4/ 23) on 5q and in 30% (3/10) on 9p. Mutations of the H-ras gene were detected in 9% (2/23). The only correlation between these genetic alterations and clinicopathologic characteristics was that mutations of the p53 gene were detected more frequently in oral SCCs with lymph node metastasis than in those without it (P < 0.05). These results demonstrate that mutations of the p53 gene and LOH on 3p and 9p frequently occur in oral SCC and play important roles in the development and/or progression of this common malignancy.

Expression of the von Hippel-Lindau disease tumour suppressor gene during human embryogenesis.

The von Hippel-Lindau (VHL) disease product is thought to down-regulate transcription by antagonizing elongin-enhanced transcriptional elongation. Germline VHL gene mutations predispose to the development of retinal, cerebellar and spinal haemangioblastomas, renal cell carcinoma and phaeochromocytoma. In addition, somatic Inactivation of the VHL gene is frequent in sporadic renal cell carcinoma and haemangioblastoma. Regulation of transcript elongation is an important control mechanism for gene expression and the VHL gene might modify the expression of proto-oncogenes and growth suppressor genes during embryogenesis. We therefore investigated the expression of VHL mRNA during human embryogenesis by in situ hybridization studies at 4, 6 and 10 weeks post conception. Although VHL mRNA was expressed in all three germ layers, strong expression was noted in the central nervous system, kidneys, testis and lung. Within the kidney, VHL mRNA was differentially expressed within renal tubules suggesting that the VHL gene product may have a specific role in kidney development. Two alternatively spliced VHL mRNAs characterized by inclusion (isoform I) or exclusion (isoform II) of exon 2 are transcribed in adult tissues. To investigate if the two isoforms are differentially expressed during embryogenesis, VHL mRNA was reverse transcribed from 13 fetal tissues (8-10 weeks gestation). The quantitative distribution of VHL mRNA within fetal tissues reflected that seen by in situ hybridization and the ratio of the two VHL isoforms was similar between tissues. Although the genes regulated by the VHL gene product have not yet been identified, our findings are compatible with the hypothesis that VHL-mediated control of transcriptional elongation may have a role in normal human development.

Germline mutations in the von Hippel-Lindau disease tumor suppressor gene: correlations with phenotype.

von Hippel-Lindau disease (VHL) is an inherited neoplastic disease characterized by a predisposition to develop retinal angiomas, central nervous system hemangioblastomas, renal cell carcinomas, pancreatic cysts, and pheochromocytomas. The VHL gene was recently isolated by positional cloning. The cDNA encodes 852 nucleotides in 3 exons. The VHL gene is unrelated to any known gene families. We identified germline mutations in 85/114 (75%) of VHL families. Clinical heterogeneity is a well-known feature of VHL. VHL families were classified into 2 types based on the presence or absence of pheochromocytoma. The types of mutations responsible for VHL without pheochromocytoma (VHL type 1) differed from those responsible for VHL with pheochromocytoma (VHL type 2). Fifty-six % of the mutations responsible for VHL type 1 were microdeletions/insertions, nonsense mutations, or deletions; 96% of the mutations responsible for VHL type 2 were missense mutations. Specific mutations in codon 238 accounted for 43% of the mutations responsible for VHL type 2. The mutations identified in these families will be useful in presymptomatic diagnosis. The identification of mutations associated with phenotypes contributes to the understanding of fundamental genetic mechanisms of VHL disease.

Detailed mapping of germline deletions of the von Hippel-Lindau disease tumour suppressor gene.

Von Hippel-Lindau disease is a dominantly inherited familial cancer syndrome characterised by the development of retinal angiomatosis, cerebellar and spinal hemangioblastoma, renal cell carcinoma, phaeochromocytoma and pancreatic tumours. A cDNA (g7) which detects frequent genomic rearrangements in VHL disease patients on Southern analysis, and contains the partial coding sequence of the VHL gene has been isolated recently. To characterise the nature of the genomic rearrangements in VHL disease we initially screened 116 patients with VHL disease and identified 22 patients (19%) with abnormal fragments in EcoR1 digested DNA probes with g7. We then established that the coding sequence contained within g7 is represented in 3 exons, and design exon specific probes to investigate the 22 patients with genomic rearrangements. All 22 patients were demonstrated to have germline deletions, but the deletions were heterogeneous with 7 patients having deletions confined to the 5' exon 1, and 8 with nonoverlapping deletions of exon 3. In 7 unrelated patients, including 2 new mutations, the germline deletions were similar in size and position. There was no relationship between the clinical phenotype and the deletion of individual exons. Although phaeochromocytoma was less frequent in kindreds with germline deletions than those without detectable deletions, the difference was not statistically significant (1/19 versus 16/72 respectively, chi 2 = 1.84 p > 0.1).

Medical genetics: advances in brief: Identification of the von Hippel-Lindau disease tumour suppressor gene

Medical genetics: advances in brief: Identification of the von Hippel-Lindau disease tumour suppressor gene

Mapping the Von Hippel-Lindau disease tumour suppressor gene: identification of germline deletions by pulsed field gel electrophoresis.

Von Hippel-Lindau (VHL) disease is a dominantly inherited familial cancer syndrome in which affected individuals have a greatly increased predisposition to the development of haemangioblastomas of the central nervous system and retina, renal cell carcinoma and phaeochromocytoma. The VHL gene has been mapped to chromosome 3p25-p26 by genetic linkage studies and we have previously demonstrated that the VHL gene is tightly linked to the D3S601 locus (Zmax = 18.86 at theta = 0.0) suggesting that D3S601 maps close to the VHL disease gene. We have constructed a long range physical map around D3S601 and screened 91 VHL patients from 80 kindreds for germline rearrangements using pulsed field gel electrophoresis. Two patients showed abnormal fragments in Mlul digested DNA probed with D3S601. Further analysis was consistent with both patients having germline deletions (approximately 120 kb and 50 kb) telomeric to D3S601. These results have (i) established the position of the VHL disease gene with respect to D3S601, (ii) refined the localisation of the VHL disease gene to a small region (approximately 50 kb) of chromosome 3p25-p26 and (iii) excluded the plasma membrane Ca(+)+-transporting ATPase isoform 2 (PMCA-2) gene as a candidate gene for VHL disease.