Familial Von Hippel-Lindau Disease Research Articles

NIMG-110. FIRST CLINICAL EXPERIENCE WITH BELZUTIFAN IN VON HIPPEL-LINDAU DISEASE-ASSOCIATED CNS HEMANGIOBLASTOMA

Abstract The authors present two cases of von Hippel-Lindau (VHL) disease-associated hemangioblastomas in the central nervous system (CNS) treated with the newly-approved HIF-2α inhibitor, belzutifan. The first case is that of a 31-year-old female with confirmed pathogenic germline VHL mutation who presented with multiple hemangioblastomas diagnosed at 25 years of age. The patient was first managed surgically with resection of three posterior fossa hemangioblastomas but re-presented five years later with headaches and paresthesias of the fingers. She was found to have interval progression of an intramedullary cervical lesion that was monitored radiographically, as well as a new cerebellar lesion. A cerebellar lesion was resected, but the cervical hemangioblastoma was not. Four months after surgery, the patient was started on belzutifan, which she tolerated without issue, and a brisk reduction in peri-lesional edema was observed in the cervical spine and remaining intracranial foci after 2 months of treatment. The second patient is a 30-year-old male with familial VHL disease, initially diagnosed after the discovery of a retinal hemangioblastoma at age 10. He was found to have multiple cerebellar hemangioblastomas, treated with resection at age 24 and then with stereotactic radiosurgery (SRS) at age 25, complicated by radiation necrosis. Imaging surveillance revealed disease progression at age 29 for which he was started on belzutifan. Follow-up imaging after three one month cycles revealed a reduction in perilesional edema and reduced lesion mass effect. Both patients tolerated belzutifan well, with only anemia and fatigue. We highlight in this report our initial experience and early imaging findings associated with belzutifan used for VHL disease-associated CNS hemangioblastomas.

First clinical experience with belzutifan in von Hippel-Lindau diseaseassociated CNS hemangioblastoma.

We present two cases of von Hippel–Lindau (VHL) disease-associated hemangioblastomas in the CNS treated with the newly approved HIF-2α inhibitor, belzutifan. The first case is a 31-year-old female with confirmed pathogenic germline VHL mutation who presented with multiple hemangioblastomas. The patient was started on belzutifan, and a brisk reduction in perilesional edema was observed after 2 months of treatment. The second patient is a 30-year-old male with familial VHL disease. Imaging revealed multiple cerebellar hemangioblastomas, and follow-up imaging after three cycles of belzutifan revealed a reduction in perilesional edema. Both patients tolerated belzutifan well, with only anemia and fatigue. We highlight our initial experience and early imaging findings associated with belzutifan in VHL disease-associated CNS hemangioblastomas.

VHL Inactivation in Precancerous Kidney Cells Induces an Inflammatory Response via ER Stress-Activated IRE1α Signaling.

Mutations and epigenetic inactivation of the tumor suppressor gene von Hippel-Lindau (VHL) are major causes of clear-cell renal cell carcinoma (ccRCC) that may originate from chronic inflammation. However, the role of VHL loss of function in the development of ccRCC via inflammation remains poorly understood. VHL-mutant cells exhibit metabolic abnormalities that can cause chronic endoplasmic reticulum (ER) stress and unfolded protein response. We hypothesize that unresolved ER stress induces the inflammatory responses observed in ccRCC. ER stress markers including BiP and XBP1s were significantly increased in cultured and primary VHL loss-of-function kidney cells. In epithelial cells, the kinase activity of IRE1α was required for the induction of NF-κB and JNK and for the recruitment of macrophages. IRE1α kinase activity was also important for the development of fibrotic phenotype in conditional Vhlh knockout mice. Our results offer insights into the therapeutic potential against ccRCC development by relieving metabolic stress. Such cancer prevention strategy may be critical for high-risk cohorts such as the familial VHL disease patients. Cancer Res; 77(13); 3406-16. ©2017 AACR.

Frequency of Von Hippel‐Lindau germline mutations in classic and non‐classic Von Hippel‐Lindau disease identified by DNA sequencing, Southern blot analysis and multiplex ligation‐dependent probe amplification

The current clinical diagnosis of Von Hippel-Lindau (VHL) disease demands at least one specific [corrected] VHL manifestation in a patient with familial VHL disease, or, in a [corrected] sporadic patient, at least two or more hemangioblastomas or a single hemangioblastoma in combination with a typical visceral lesion. To evaluate this definition, we studied the frequency of germline VHL mutation in three patients groups: (i) multi-organ involvement (classic VHL), (ii) limited VHL manifestations meeting criteria (non-classic VHL) and (iii) patients with VHL-associated tumors not meeting current diagnostic VHL criteria. In addition, we validated multiplex ligation-dependent probe amplification (MLPA) as a rapid and reliable quantitative method for the identification of germline VHL deletions. The frequency of germline VHL mutations was very high in classic VHL cases with multi-organ involvement (95%), lower in non-classic cases that meet current diagnostic criteria but have limited VHL manifestations or single-organ involvement (24%) and low (3.3%), but tangible in cases not meeting current diagnostic VHL criteria. The detection of germline VHL mutations in patients or families with limited VHL manifestations, or single-organ involvement is relevant for follow-up of probands and early identification of at-risk relatives.

Associations between VHL genotype and clinical phenotype in familial von Hippel–Lindau disease

Von Hippel-Lindau (VHL) disease is an autosomal dominant hereditary disorder associated with tumours and cysts in the central nervous system (CNS) and other visceral organs. Germline mutations in the VHL gene on chromosome 3p25-26 are considered the cause of this disease. We studied six patients with VHL disease and their relatives. Loss of heterozygosity (LOH) was determined by five flanking microsatellite polymorphic markers in the VHL locus. Multiplex ligation-dependent probe amplification (MLPA) and quantitative real-time polymerase chain reaction (qPCR) amplification were used to detect the genomic deletions. Single-strand conformation polymorphism (SSCP) analysis was applied to test for sequence variations. Three germline deletions in the VHL gene (142.9, 53.3 and 3.3 kb) were found by MLPA. These deletions were defined clearly by qPCR analyses. The142.9 kb germline deletion was significantly associated with patients with CNS haemangioblastomas (P < 0.01 by Fisher's exact test), and one missense mutation (Gln209Arg) was detected from a patient with a pancreatic cyst in the same family. LOH was also detected from a patient with bilateral renal cell carcinomas. Diverse genetic conditions are associated with the clinical manifestations of VHL disease. Genomic deletions that can be detected by MLPA or qPCR are major causes for this syndrome. Missense mutations and LOH accompanying the disease lead to complex clinical symptoms and genotypic determination can facilitate a clinical diagnosis because of their strong association.

Expression of p53 in renal carcinoma cells is independent of pVHL

Renal clear-cell carcinoma (RCC) is the predominant form of kidney cancer and is highly refractory to conventional anti-cancer therapies. The status of p53 tumor suppressor gene has been correlated with the efficacy of radio- and chemotherapies, where presence of mutant p53 is associated with reduced responsiveness to treatment. However, p53 itself is rarely mutated in RCC, rather suggesting that the p53 pathway might be compromized in RCC cells. In support of this notion, the transactivation property of normal p53 was shown to be repressed in various transformed kidney epithelial cells via an unknown dominant-negative mechanism. Mutation of the von Hippel-Lindau ( VHL) gene causes familial VHL disease, which includes predisposition to RCC. Moreover, biallelic inactivation of VHL has been observed in the vast majority of sporadic RCC. Recently, the expression of pVHL in RCC cells was demonstrated to elevate the expression of p53 by inducing the binding of RNA-stabilizing protein HuR to the 3′untranslated region of p53 mRNA. Contrary to this finding, we report here that the reconstitution of a variety of VHL(−/−) RCC lines including 786-O, RCC4, and A498 or non-RCC cells with wild-type pVHL does not influence the expression of p53 and fails to induce p53-responsive gene p21 CIP1/WAF1 or p53-responsive reporters. These results suggest that the expression of p53 in RCC cells is independent of pVHL.

PVHL modification by NEDD8 is required for fibronectin matrix assembly and suppression of tumor development.

Functional inactivation of the von Hippel-Lindau (VHL) tumor suppressor gene is the cause of the familial VHL disease and most sporadic renal clear-cell carcinomas (RCC). pVHL has been shown to play a role in the destruction of hypoxia-inducible factor alpha (HIF-alpha) subunits via ubiquitin-mediated proteolysis and in the regulation of fibronectin matrix assembly. Although most disease-causing pVHL mutations hinder the regulation of the HIF pathway, every disease-causing pVHL mutant tested to date has failed to promote the assembly of the fibronectin matrix, underscoring its potential importance in VHL disease. Here, we report that a ubiquitin-like molecule called NEDD8 covalently modifies pVHL. A nonneddylateable pVHL mutant, while retaining its ability to ubiquitylate HIF, failed to bind to and promote the assembly of the fibronectin matrix. Expression of the neddylation-defective pVHL in RCC cells, while restoring the regulation of HIF, failed to promote the differentiated morphology in a three-dimensional growth assay and was insufficient to suppress the formation of tumors in SCID mice. These results suggest that NEDD8 modification of pVHL plays an important role in fibronectin matrix assembly and that in the absence of such regulation, an intact HIF pathway is insufficient to prevent VHL-associated tumorigenesis.

Multiple Splice Variants of the Human HIF-3α Locus Are Targets of the von Hippel-Lindau E3 Ubiquitin Ligase Complex

Functional inactivation of the von Hippel-Lindau (VHL) tumor suppressor protein is the cause of familial VHL disease and sporadic kidney cancer. The VHL gene product (pVHL) is a component of an E3 ubiquitin ligase complex that targets the hypoxia-inducible factor (HIF) 1 and 2 alpha subunits for polyubiquitylation. This process is dependent on the hydroxylation of conserved proline residues on the alpha subunits of HIF-1/2 in the presence of oxygen. In our effort to identify orphan HIF-like proteins in the data base that are potential targets of the pVHL complex, we report multiple splice variants of the human HIF-3 alpha locus as follows: hHIF-3 alpha 1, hHIF-3 alpha 2 (also referred to as hIPAS; human inhibitory PAS domain protein), hHIF-3 alpha 3, hHIF-3 alpha 4, hHIF-3 alpha 5, and hHIF-3 alpha 6. We demonstrate that the common oxygen-dependent degradation domain of hHIF-3 alpha 1-3 splice variants is targeted for ubiquitylation by the pVHL complex in vitro and in vivo. This activity is enhanced in the presence of prolyl hydroxylase and is dependent on a proline residue at position 490. Furthermore, the ubiquitin conjugation occurs on lysine residues at position 465 and 568 within the oxygen-dependent degradation domain. These results demonstrate additional targets of the pVHL complex and suggest a growing complexity in the regulation of hypoxia-inducible genes by the HIF family of transcription factors.

Clinicopathological study of vascular endothelial growth factor (VEGF), p53, and proliferative potential in familial von Hippel-Lindau disease and sporadic hemangioblastomas.

We examined the clinical characteristics and prognosis in six patients with familial von Hippel-Lindau (VHL) disease and seven with sporadic hemangioblastomas. The expression of vascular endothelial growth factor (VEGF), p53 protein, and proliferative potential with Ki67 monoclonal antibody (MIB-1) was compared using immunohistochemical methods between sporadic and VHL disease-associated hemangioblastomas. Patients with sporadic CNS hemangioblastomas were treated by total removal of the tumors, and they had a good long-term prognosis without neurological deficits on recurrence. However, patients with familial VHL disease often had multiple hemangioblastomas in the CNS and visceral tumors. Even if total removal of CNS hemangioblastomas in patients with VHL disease was performed initially, small multiple hemangioblastomas recurred during long-term follow-up in areas remote from the primary region resected by surgery. All of the hemangioblastomas displayed extensive overexpression of VEGF protein, with moderate to marked proliferation of blood vessels. The MIB-1 indices showed low values of 0.8% as the mean, with a range of 0.03%-2.1% for all the hemangioblastomas. None of the hemangioblastomas expressed p53 protein. The hemangioblastomas in patients with VHL disease were multiple in the CNS and were combined with visceral tumors. Patients with VHL disease had a poor long-term prognosis, in contrast to those with sporadic hemangioblastomas. The immunohistochemical findings for VEGF protein, p53 protein, and MIB-1 did not differ significantly between the sporadic and VHL disease-associated hemangioblastomas.

Inheritance of Hippel-Lindau Disease: A Rare Case of Maxillary Bone Metastasis

A rare case of familial Hippel-Lindau disease, which is an autosomal dominant disorder with inherited susceptibility to various forms of cancer, is reported in a 46-year-old father and his sons. The father complained of a malignant hypernephroma, which metastasized in the upper jaw 6 months later. As in this patient, renal cell carcinomas are fatal and are exhibited at an early age. Consequentially, patients with familial von Hippel-Lindau disease exhibiting cases of renal cell carcinoma should be examined very carefully in the head and neck region to detect and treat metastases as early as possible.