Molecular basis of the VHL hereditary cancer syndrome

The role of metabolic reprogramming in kidney cancer

Metabolic reprogramming is a cellular process in which cells modify their metabolic patterns to meet energy requirements, promote proliferation, and enhance resistance to external stressors. This process also introduces new functionalities to the cells. The 'Warburg effect' is a well-studied example of metabolic reprogramming observed during tumorigenesis. Recent studies have shown that kidney cells undergo various forms of metabolic reprogramming following injury. Moreover, metabolic reprogramming plays a crucial role in the progression, prognosis, and treatment of kidney cancer. This review offers a comprehensive examination of renal cancer, metabolic reprogramming, and its implications in kidney cancer. It also discusses recent advancements in the diagnosis and treatment of renal cancer.

Consensus Guidelines for Ocular Surveillance of von Hippel-Lindau Disease

PURPOSE

To develop guidelines for ocular surveillance and early intervention for individuals with von Hippel-Lindau (VHL) disease.

DESIGN

Systematic review of the literature.

PARTICIPANTS

Expert panel of retina specialists and ocular oncologists.

METHODS

A consortium of experts on clinical management of all-organ aspects of VHL disease was convened. Working groups with expertise in organ-specific features of VHL disease were tasked with development of evidence-based guidelines for each organ system. The ophthalmology subcommittee formulated questions for consideration and performed a systematic literature review. Evidence was graded for topic quality and relevance and the strength of each recommendation, and guideline recommendations were developed.

RESULTS

The quality of evidence was limited, and no controlled clinical trial data were available. Consensus guidelines included: (1) individuals with known or suspected VHL disease should undergo periodic ocular screening (evidence type, III; evidence strength, C; degree of consensus, 2A); (2) patients at risk of VHL disease, including first-degree relatives of patients with known VHL disease, or any patient with single or multifocal retinal hemangioblastomas (RHs), should undergo genetic testing for pathologic VHL disease gene variants as part of an appropriate medical evaluation (III/C/2A); (3) ocular screening should begin within 12 months after birth and continue throughout life (III/C/2A); (4) ocular screening should occur approximately every 6 to 12 months until 30 years of age and then at least yearly thereafter (III/C-D/2A); (5) ocular screening should be performed before a planned pregnancy and every 6 to 12 months during pregnancy (IV/D/2A); (6) ultra-widefield color fundus photography may be helpful in certain circumstances to monitor RHs, and ultra-widefield fluorescein angiography may be helpful in certain circumstances to detect small RHs (IV/D/2A); (7) patients should be managed, whenever possible, by those with subspecialty training, with experience with VHL disease or RHs, or with both and ideally within the context of a multidisciplinary center capable of providing multiorgan surveillance and access to genetic testing (IV/D/2A); (8) extramacular or extrapapillary RHs should be treated promptly (III/C/2A).

CONCLUSIONS

Based on available evidence from observational studies, broad agreement was reached for a strategy of lifelong surveillance and early treatment for ocular VHL disease. These guidelines were endorsed by the VHL Alliance and the International Society of Ocular Oncology and were approved by the American Academy of Ophthalmology Board of Trustees.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Von Hippel Lindau tumor suppressor controls m6A-dependent gene expression in renal tumorigenesis

N6-Methyladenosine (m6A) is the most abundant posttranscriptional modification, and its contribution to cancer evolution has recently been appreciated. Renal cancer is the most common adult genitourinary cancer, approximately 85% of which is accounted for by the clear cell renal cell carcinoma (ccRCC) subtype characterized by VHL loss. However, it is unclear whether VHL loss in ccRCC affects m6A patterns. In this study, we demonstrate that VHL binds and promotes METTL3/METTL14 complex formation while VHL depletion suppresses m6A modification, which is distinctive from its canonical E3 ligase role. m6A RNA immunoprecipitation sequencing (RIP-Seq) coupled with RNA-Seq allows us to identify a selection of genes whose expression may be regulated by VHL-m6A signaling. Specifically, PIK3R3 is identified to be a critical gene whose mRNA stability is regulated by VHL in a m6A-dependent but HIF-independent manner. Functionally, PIK3R3 depletion promotes renal cancer cell growth and orthotopic tumor growth while its overexpression leads to decreased tumorigenesis. Mechanistically, the VHL-m6A-regulated PIK3R3 suppresses tumor growth by restraining PI3K/AKT activity. Taken together, we propose a mechanism by which VHL regulates m6A through modulation of METTL3/METTL14 complex formation, thereby promoting PIK3R3 mRNA stability and protein levels that are critical for regulating ccRCC tumorigenesis.

Rationale for immune checkpoint inhibitors plus targeted therapy for advanced renal cell carcinoma

Renal cell carcinoma (RCC) is a frequent urological malignancy characterized by a high rate of metastasis and lethality. The treatment strategy for advanced RCC has moved through multiple iterations over the past three decades. Initially, cytokine treatment was the only systemic treatment option for patients with RCC. With the development of medicine, antiangiogenic agents targeting vascular endothelial growth factor and mammalian target of rapamycin and immunotherapy, immune checkpoint inhibitors (ICIs) have emerged and received several achievements in the therapeutics of advanced RCC. However, ICIs have still not brought completely satisfactory results due to drug resistance and undesirable side effects. For the past years, the interests form researchers have been attracted by the combination of ICIs and targeted therapy for advanced RCC and the angiogenesis and immunogenic tumor microenvironmental variations in RCC. Therefore, we emphasize the potential principle and the clinical progress of ICIs combined with targeted treatment of advanced RCC, and summarize the future direction.

Diagnostic, prognostic, and therapeutic potential of exosomal microRNAs in renal cancer

Renal cell carcinoma (RCC) arises from the tubular epithelial cells of the nephron. It has the highest mortality rate among urological cancers. There are no effective therapeutic approaches and no non-invasive biomarkers for diagnosis and follow-up. Thus, suitable novel biomarkers and therapeutic targets are essential for improving RCC diagnosis/prognosis and treatment. Circulating exosomes such as exosomal microRNAs (Exo-miRs) provide non-invasive prognostic/diagnostic biomarkers and valuable therapeutic targets, as they can be easily isolated and quantified and show high sensitivity and specificity. Exosomes secreted by an RCC can exhibit alterations in the miRs' profile that may reflect the cellular origin and (patho)physiological state, as a ''signature'' or ''fingerprint'' of the donor cell. It has been shown that the transportation of renal-specific miRs in exosomes can be rapidly detected and measured, holding great potential as biomarkers in RCC. The present review highlights the studies reporting tumor microenvironment-derived Exo-miRs with therapeutic potential as well as circulating Exo-miRs as potential diagnostic/prognostic biomarkers in patients with RCC.

HIF-1α Mediates Immunosuppression and Chemoresistance in Colorectal Cancer by Inhibiting CXCL9, -10 and -11

Uncertainty exists regarding the mechanisms by which hypoxia-inducible factors (HIFs) control CD8+T-cell migration into tumor microenvironments. Here, we found that HIF-1α knockdown or overexpression resulted in increased or decreased CXCL9, -10, and -11 expression in vitro, respectively. Gene Set Variation Analysis revealed that elevated HIF-1α levels correlated with a poor prognosis, severe pathological stage, and an absence of CD8+ T cells in the tumor microenvironment in colorectal cancer (CRC) patients. HIF-1α was inversely associated with pathways beneficial to anti-tumor immunotherapy and cytokine/chemokine function. In vivo, inhibiting HIF-1α or its upstream regulator BIRC2 significantly suppressed tumor growth and promoted CD8+ T-cell infiltration. CXCR3 neutralizing antibodies reversed these effects, implicating the involvement of CXCL9, -10, and -11/CXCR3 axis. The presence of HIF-1α weakened the upregulation of CXCL9, -10, and -11 by bleomycin and doxorubicin. Combining HIF-1α inhibition with bleomycin promoted CD8+ T-cell infiltration and tumor suppression in vivo. Moreover, doxorubicin could upregulate CXCL9, -10 and -11 by suppressing HIF-1α. Our findings highlight the potential of HIF-1α inhibition to improve CRC microenvironments and increase chemotherapy sensitivity.

The protein tyrosine phosphatase PPH-7 is required for fertility and embryonic development in C. elegans at elevated temperatures

Post-translational modifications are key in the regulation of activity, structure, localization, and stability of most proteins in eukaryotes. Phosphorylation is potentially the most studied post-translational modification, also due to its reversibility and thereby the regulatory role this modification often plays. While most research attention was focused on kinases in the past, phosphatases remain understudied, most probably because the addition and presence of the modification is more easily studied than its removal and absence. Here, we report the identification of an uncharacterized protein tyrosine phosphatase PPH-7 in C. elegans, a member of the evolutionary conserved PTPN family of phosphatases. Lack of PPH-7 function led to reduction of fertility and embryonic lethality at elevated temperatures. Proteomics revealed changes in the regulation of targets of the von Hippel-Lindau (VHL) E3 ligase, suggesting a potential role for PPH-7 in the regulation of VHL.

Kinome-wide siRNA screen identifies a DCLK2-TBK1 oncogenic signaling axis in clear cell renal cell carcinoma

TANK-binding kinase 1 (TBK1) is a potential therapeutic target in multiple cancers, including clear cell renal cell carcinoma (ccRCC). However, targeting TBK1 in clinical practice is challenging. One approach to overcome this challenge would be to identify an upstream TBK1 regulator that could be targeted therapeutically in cancer specifically. In this study, we perform a kinome-wide small interfering RNA (siRNA) screen and identify doublecortin-like kinase 2 (DCLK2) as a TBK1 regulator in ccRCC. DCLK2 binds to and directly phosphorylates TBK1 on Ser172. Depletion of DCLK2 inhibits anchorage-independent colony growth and kidney tumorigenesis in orthotopic xenograft models. Conversely, overexpression of DCLK2203, a short isoform that predominates in ccRCC, promotes ccRCC cell growth and tumorigenesis in vivo. Mechanistically, DCLK2203 elicits its oncogenic signaling via TBK1 phosphorylation and activation. Taken together, these results suggest that DCLK2 is a TBK1 activator and potential therapeutic target for ccRCC.

A serum panel of three microRNAs may serve as possible biomarkers for kidney renal clear cell carcinoma

BACKGROUND

Although non-invasive radiological techniques are widely applied in kidney renal clear cell carcinoma (KIRC) diagnosis, more than 50% of KIRCs are detected incidentally during the diagnostic procedures to identify renal cell carcinoma (RCC). Thus, sensitive and accurate KIRC diagnostic methods are required. Therefore, in this study, we aimed to identify KIRC-associated microRNAs (miRNAs).

METHODS

This three-phase study included 224 participants (112 each of patients with KIRC and healthy controls (NCs)). RT-qPCR was used to evaluate miRNA expression in KIRC and NC samples. Receiver operating characteristic (ROC) curves and the area under the ROC curve (AUC) were used to predict the usefulness of serum miRNAs in KIRC diagnosis. In addition, we performed survival and bioinformatics analyses.

RESULTS

We found that miR-1-3p, miR-129-5p, miR-146b-5p, miR-187-3p, and miR-200a-3p were significantly differentially expressed in patients with KIRC. A panel consisting of three miRNAs (miR-1-3p, miR-129-5p, and miR-146b-5p) had an AUC of 0.895, ranging from 0.848 to 0.942. In addition, using the GEPIA database, we found that the miRNAs were associated with CREB5. According to the survival analysis, miR-146b-5p overexpression was indicative of a poorer prognosis in patients with KIRC.

CONCLUSIONS

The identified three-miRNA panel could serve as a non-invasive indicator for KIRC and CREB5 as a potential target gene for KIRC treatment.

[The development of innovative therapeutic drugs targeting hypoxia responses]

The 2019 Nobel Prize in Physiology or Medicine was awarded to Dr. William G. Kaelin Jr, Dr. Peter J. Ratcliffe, and Dr. Gregg L. Semenza for their elucidation of new physiological mechanisms "How cells sense and adapt to oxygen availability". Moreover, two different drugs, HIF-PH inhibitors and HIF-2 inhibitors were also developed based on the discovery. Interestingly, those three doctors have different backgrounds as a medical oncologist, a nephrologist, and a pediatrician, respectively. They have started the research based on their own unique perspectives and eventually merged as "the elucidation of the response mechanism of living organisms to hypoxic environments". In this review, we will explain how the translational research that has begun to solve unmet clinical needs successfully contributed to the development of innovative therapeutic drugs.

A nonsense mutation in VHL causing Von Hippel-Lindau syndrome in a large Chinese family-a genetic study of familial neoplastic disease

Von Hippel-Lindau (VHL) syndrome is a multi-organ neoplastic disease characterized by highly vascular and cystic tumors in the central nervous system (CNS), retina, and visceral lesions, which are mainly caused by germline mutations in VHL. We aimed to detect novel mutations in VHL gene in families with VHL. Here, a large consanguineous four-generation family with variant phenotypes of VHL syndrome was recruited, and its molecular genetics were tested via Sanger sequencing. And various tools and databases were used to predict the variant pathogenicity, frequency, and protein function. Genetic investigation detected a c.351G > A nonsense mutation in VHL that altered the downstream reading frame and created a premature TGA stop signal, resulting in severely truncated pVHL (p.Trp117Ter). This mutation is absent from most public databases, and functional prediction bioinformatic tools demonstrated that this residue is conserved and that this variant is highly likely to be deleterious. The c.315G > A nonsense mutation in VHL is the causal mutation of this kindred that may lead to clear familial aggregation of VHL syndrome because of the dysfunction of the truncated pVHL.

Hypoxia stabilizes SETDB1 to maintain genome stability

Von Hippel-Lindau (VHL) is a tumor suppressor that functions as the substrate recognition subunit of the CRL2VHL E3 complex. While substrates of VHL have been identified, its tumor suppressive role remains to be fully understood. For further determination of VHL substrates, we analyzed the physical interactome of VHL and identified the histone H3K9 methyltransferase SETBD1 as a novel target. SETDB1 undergoes oxygen-dependent hydroxylation by prolyl hydroxylase domain proteins and the CRL2VHL complex recognizes hydroxylated SETDB1 for ubiquitin-mediated degradation. Under hypoxic conditions, SETDB1 accumulates by escaping CRL2VHL activity. Loss of SETDB1 in hypoxia compared with that in normoxia escalates the production of transposable element-derived double-stranded RNAs, thereby hyperactivating the immune-inflammatory response. In addition, strong derepression of TEs in hypoxic cells lacking SETDB1 triggers DNA damage-induced death. Our collective results support a molecular mechanism of oxygen-dependent SETDB1 degradation by the CRL2VHL E3 complex and reveal a role of SETDB1 in genome stability under hypoxia.

The potential of targeting cuproptosis in the treatment of kidney renal clear cell carcinoma

Renal cell carcinoma (RCC) is one of the top ten malignancies and tumor-related causes of death worldwide. The most common histologic subtype is kidney renal clear cell carcinoma (KIRC), accounting for approximately 75% of all RCC cases. Early resection is considered the basic treatment for patients with KIRC. However, approximately 30% of these patients experience recurrence post-operation. Cuproptosis, an autonomous mechanism for controlling cell death, encompasses various molecular mechanisms and multiple cellular metabolic pathways. These pathways mainly include copper metabolic signaling pathways, mitochondrial metabolism signaling pathways, and lipoic acid pathway signaling pathways. Recent evidence shows that cuproptosis is identified as a key cell death modality that plays a meaningful role in tumor progression. However, there is no published systematic review that summarizes the correlation between cuproptosis and KIRC, despite the fact that investigations on cuproptosis and the pathogenesis of KIRC have increased in past years. Researchers have discovered that exogenous copper infusion accelerates the dysfunction of mitochondrial dysfunction and suppresses KIRC cells by inducing cuproptosis. The levels of tricarboxylic acid cycle proteins, lipoic acid protein, copper, and ferredoxin 1 (FDX1) were dysregulated in KIRC cells, and the prognosis of patients with high FDX1 expression is better than that of patients with low expression. Cuproptosis played an indispensable role in the regulation of tumor microenvironment features, tumor progression, and long-term prognosis of KIRC. In this review, we summarized the systemic and cellular metabolic processes of copper and the copper-related signaling pathways, highlighting the potential targets related to cuproptosis for KIRC treatment.

VHL-deficiency leads to reductive stress in renal cells

Heritable renal cancer syndromes (RCS) are associated with numerous chromosomal alterations including inactivating mutations in von Hippel-Lindau (VHL) gene. Here we identify a novel aspect of the phenotype in VHL-deficient human renal cells. We call it reductive stress as it is characterised by increased NADH/NAD+ ratio that is associated with impaired cellular respiration, impaired CAC activity, upregulation of reductive carboxylation of glutamine and accumulation of lipid droplets in VHL-deficient cells. Reductive stress was mitigated by glucose depletion and supplementation with pyruvate or resazurin, a redox-reactive agent. This study demonstrates for the first time that reductive stress is a part of the phenotype associated with VHL-deficiency in renal cells and indicates that the reversal of reductive stress can augment respiratory activity and CAC activity, suggesting a strategy for altering the metabolic profile of VHL-deficient tumours.

Neurofibromatosis type1, type 2, tuberous sclerosis and Von Hippel-Lindau disease

Neurocutaneous syndromes (also known as phakomatoses) are heterogenous group of disorders that involve derivatives of the neuroectoderm. Each disease has diagnostic and pathognomonic criteria, once identified, thorough clinical examination to the patient and the family members should be done. Magnetic resonance imaging (MRI) is used to study the pathognomonic findings withing the CNS (Evans et al. in Am J Med Genet A 152A:327-332, 2010). This chapter includes the 4 most common syndromes faced by neurosurgeons and neurologists; neurofibromatosis types 1 and 2, tuberous sclerosis and Von Hippel-Lindau disease. Each syndrome has specific genetic anomaly that involves a tumor suppressor gene and the loss of inhibition of specific pathways. The result is a spectrum of cutaneous manifestations and neoplasms.

Guidelines for surveillance of patients with von Hippel-Lindau disease: Consensus statement of the International VHL Surveillance Guidelines Consortium and VHL Alliance

Von Hippel‐Lindau disease is a rare inherited cancer‐predisposition syndrome. The authors report the updated recommendations for the multiorgan surveillance protocols.

Genomic profiles of renal cell carcinoma in a small Chinese cohort

Objectives

Our aim was to describe the molecular characteristics of Renal Cell Carcinoma (RCC) and develop a small panel of RCC-associated genes from a large panel of cancer-related genes.

Materials and methods

Clinical data of 55 patients with RCC diagnosed in four hospitals from September 2021 to August 2022 were collected. Among the 55 patients, 38 were diagnosed with clear cell RCC (ccRCC), and the other 17 were diagnosed with non-clear cell RCC (nccRCC), including 10 cases of papillary renal cell carcinoma, 2 cases of hereditary leiomyomatosis and RCC syndrome (HLRCC), 1 eosinophilic papillary RCC, 1 tubular cystic carcinoma, 1 TFE3 gene fusion RCC, and 2 RCC with sarcomatoid differentiation. For each patient, 1123 cancer-related genes and 79 RCC-associated genes were analyzed.

Results

The most frequent mutations in a large panel of 1123 cancer-related genes in the overall population of RCC patients were VHL (51%), PBRM1 (35%), BAP1 (16%), KMT2D (15%), PTPRD (15%), and SETD2 (15%). For ccRCC patients, mutations in VHL, PBRM1, BAP1, and SERD2 can reach 74%, 50%, 24%, and 18%, respectively, while for nccRCC patients, the most frequent mutation was FH (29%), MLH3 (24%), ARID1A (18%), KMT2D (18%), and CREBBP (18%). The germline mutation rate in all 55 patients reached 12.7% (five with FH, one with ATM, and one with RAD50). The small panel containing only 79 RCC-associated genes demonstrated that mutations of VHL, PBRM1, BAP1, and SETD2 in ccRCC patients were 74%, 50%, 24%, and 18% respectively, while for the nccRCC cohort, the most frequent mutations were FH (29%), ARID1A (18%), ATM (12%), MSH6 (12%), BRAF (12%), and KRAS (12%). For ccRCC patients, the spectrum of mutations by large and small panels was almost the same, while for nccRCC patients, the mutation spectrum showed some differences. Even though the most frequent mutations (FH and ARID1A) in nccRCC were both demonstrated by large panels and small panels, other less frequent mutations such as MLH3, KMT2D, and CREBBP were not shown by the small panel.

Conclusion

Our study revealed that nccRCC is more heterogeneous than ccRCC. For nccRCC patients, the small panel shows a more clear profile of genetic characteristics by replacing MLH3, KMT2D, and CREBBP with ATM, MSH6, BRAF, and KRAS, which may help predict prognosis and make clinical decisions.

Pharmacologic targeting of Nedd8-activating enzyme reinvigorates T-cell responses in lymphoid neoplasia

Neddylation is a sequential enzyme-based process which regulates the function of E3 Cullin-RING ligase (CRL) and thus degradation of substrate proteins. Here we show that CD8+ T cells are a direct target for therapeutically relevant anti-lymphoma activity of pevonedistat, a Nedd8-activating enzyme (NAE) inhibitor. Pevonedistat-treated patient-derived CD8+ T cells upregulated TNFα and IFNγ and exhibited enhanced cytotoxicity. Pevonedistat induced CD8+ T-cell inflamed microenvironment and delayed tumor progression in A20 syngeneic lymphoma model. This anti-tumor effect lessened when CD8+ T cells lost the ability to engage tumors through MHC class I interactions, achieved either through CD8+ T-cell depletion or genetic knockout of B2M. Meanwhile, loss of UBE2M in tumor did not alter efficacy of pevonedistat. Concurrent blockade of NAE and PD-1 led to enhanced tumor immune infiltration, T-cell activation and chemokine expression and synergistically restricted tumor growth. shRNA-mediated knockdown of HIF-1α, a CRL substrate, abrogated the in vitro effects of pevonedistat, suggesting that NAE inhibition modulates T-cell function in HIF-1α-dependent manner. scRNA-Seq-based clinical analyses in lymphoma patients receiving pevonedistat therapy demonstrated upregulation of interferon response signatures in immune cells. Thus, targeting NAE enhances the inflammatory T-cell state, providing rationale for checkpoint blockade-based combination therapy.

On the Roles of the Nuclear Non-Coding RNA-Dependent Membrane-Less Organelles in the Cellular Stress Response

At the beginning of the 21st century, it became obvious that radical changes had taken place in the concept of living matter and, in particular, in the concept of the organization of intracellular space. The accumulated data testify to the essential importance of phase transitions of biopolymers (first of all, intrinsically disordered proteins and RNA) in the spatiotemporal organization of the intracellular space. Of particular interest is the stress-induced reorganization of the intracellular space. Examples of organelles formed in response to stress are nuclear A-bodies and nuclear stress bodies. The formation of these organelles is based on liquid-liquid phase separation (LLPS) of intrinsically disordered proteins (IDPs) and non-coding RNA. Despite their overlapping composition and similar mechanism of formation, these organelles have different functional activities and physical properties. In this review, we will focus our attention on these membrane-less organelles (MLOs) and describe their functions, structure, and mechanism of formation.

Radiogenomics in Renal Cancer Management-Current Evidence and Future Prospects

Renal cancer management is challenging from diagnosis to treatment and follow-up. In cases of small renal masses and cystic lesions the differential diagnosis of benign or malignant tissues has potential pitfalls when imaging or even renal biopsy is applied. The recent artificial intelligence, imaging techniques, and genomics advancements have the ability to help clinicians set the stratification risk, treatment selection, follow-up strategy, and prognosis of the disease. The combination of radiomics features and genomics data has achieved good results but is currently limited by the retrospective design and the small number of patients included in clinical trials. The road ahead for radiogenomics is open to new, well-designed prospective studies, with large cohorts of patients required to validate previously obtained results and enter clinical practice.

Two Single Nucleotide Polymorphisms in the Von Hippel-Lindau Tumor Suppressor Gene in Patients with Clear Cell Renal Cell Carcinoma

The most common subtype of renal cell carcinoma (RCC) is clear cell type (ccRCC), which accounts for approximately 75% of cases. von Hippel-Lindau (VHL) gene has been shown to be affected in more than half of ccRCC cases. Two single nucleotide polymorphisms (SNPs) located in VHL gene, rs779805 and rs1642742, are reported to be involved in the occurrence of ccRCC. The aim of this study was to assess their associations with clinicopathologic and immunohistochemical parameters, as well as risk and survival of ccRCC. The study population consisted of 129 patients. No significant differences in genotype or allele frequencies of VHL gene polymorphisms were observed between ccRCC cases and control population, and we have found that our results do not indicate a significant relationship of these SNPs with respect to ccRCC susceptibility. Additionally, we did not observe a significant association of these two SNPs with ccRCC survival. However, our results conclude that rs1642742 and rs779805 in the VHL gene are associated with increased tumor size, which is the most important prognostic indicator of renal cancer. Moreover, our analysis showed that patients with genotype AA of rs1642742 have a trend towards higher likelihood of developing ccRCC within their lifetime, while allele G of rs779805 can have a preventive effect against the development of renal cancer in stage 1. Therefore, these SNPs in VHL may be useful as genetic tumor markers for the molecular diagnostics for ccRCC patients.

Caveolin-1 suppresses hippocampal neuron apoptosis via the regulation of HIF1α in hypoxia in naked mole-rats

Naked mole-rats (NMRs) (Heterocephalus glaber) are highly social and subterranean rodents with large communal colonies in burrows containing low oxygen levels. The inhibition of severe hypoxic conditions is of particular interest to this study. To understand the mechanisms that facilitate neuronal preservation during hypoxia, we investigated the proteins regulating hypoxia tolerance in NMR hippocampal neurons. Caveolin-1 (Cav-1), a transmembrane scaffolding protein, confers prosurvival signalling in the central nervous system. The present study aimed to investigate the role of Cav-1 in hypoxia-induced neuronal injury. Western blotting analysis and immunocytochemistry showed that Cav-1 expression was significantly upregulated in NMR hippocampal neurons under 8% O₂ conditions for 8 h. Cav-1 alleviates apoptotic neuronal death from hypoxia. Downregulation of Cav-1 by lentiviral vectors suggested damage to NMR hippocampal neurons under hypoxic conditions in vitro and in vivo. Overexpression of Cav-1 by LV-Cav-1 enhanced hypoxic tolerance of NMR hippocampal neurons in vitro and in vivo. Mechanistically, the levels of hypoxia inducible factor-1α (HIF-1α) are also increased under hypoxic conditions. After inhibiting the binding of HIF-1α to hypoxia response elements in the DNA by echinomycin, Cav-1 levels were downregulated significantly. Furthermore, chromatin immunoprecipitation assays showed the direct role of HIF1α in regulating the expression levels of Cav-1 in NMR hippocampal neurons under hypoxic conditions. These findings suggest that Cav-1 plays a critical role in modulating the apoptosis of NMR hippocampal neurons and warrant further studies targeting Cav-1 to treat hypoxia-associated brain diseases.

The role of immunomodulatory metabolites in shaping the inflammatory response of macrophages

Macrophage activation has long been implicated in a myriad of human pathophysiology, particularly in the context of the dysregulated capacities of an unleashing intracellular or/and extracellular inflammatory response. A growing number of studies have functionally coupled the macrophages' inflammatory capacities with dynamic metabolic reprogramming which occurs during activation, albeit the results have been mostly interpreted through classic metabolism point of view; macrophages take advantage of the rewired metabolism as a source of energy and for biosynthetic precursors. However, a specific subset of metabolic products, namely immune-modulatory metabolites, has recently emerged as significant regulatory signals which control inflammatory responses in macrophages and the relevant extracellular milieu. In this review, we introduce recently highlighted immuno-modulatory metabolites, with the aim of understanding their physiological and pathological relevance in the macrophage inflammatory response. [BMB Reports 2022; 55(11): 519-527].

Characterization of Microscopic Multicellular Foci in Grossly Normal Renal Parenchyma of Von Hippel-Lindau Kidney

Background and Objectives: This study aims to describe the earliest renal lesions in patients with von Hippel-Lindau (VHL) disease, especially the multicellular microscopic pathologic events, to get information into the genesis of renal neoplasms in this condition. Materials and Methods: Multicellular events were identified, and 3dimensional reconstruction was performed in grossly normal kidney parenchyma from VHL disease patients by using H&E-stained slides previously prepared. Results: The lesions were measured and the volume of clusters was calculated. Immunohistochemistry was performed for downstream HIF-target protein carbonic anhydrase 9 (CAIX) as well as CD34 for assessment of angiogenesis. We divided lesions into four types according to lesion height/size. The number of lesions was markedly decreased from lesion 1 (smallest) to lesion 2, then from lesions 2 to 3, and again from lesion 3 to 4. Distribution was highly consistent in the four cases, and the same decrement pattern was seen in all blocks studied. The volumes of clusters were measured and divided into three categories according to their volume. The most frequent pathologic event in VHL kidneys was category 1 (smallest volume), then category 2, and then category 3. Conclusion: We demonstrate that tracking histologic and morphologic changes in 3 dimensions of multicellular microscopic pathologic events enabled us to confirm a protracted sequence of events from smaller to larger cellular amplification events in VHL kidney.

Diagnostic and Prognostic Biomarkers in Renal Clear Cell Carcinoma

Renal clear cell carcinoma (ccRCC) comprises over 75% of all renal tumors and arises in the epithelial cells of the proximal convoluted tubule. Molecularly ccRCC is characterized by copy number alterations (CNAs) such as the loss of chromosome 3p and VHL inactivation. Additional driver mutations (SETD2, PBRM1, BAP1, and others) promote genomic instability and tumor cell metastasis through the dysregulation of various metabolic and immune-response pathways. Many researchers identified mutation, gene expression, and proteomic signatures for early diagnosis and prognostics for ccRCC. Despite a tremendous influx of data regarding DNA alterations, gene expression, and protein expression, the incorporation of these analyses for diagnosis and prognosis of RCC into the clinical application has not been implemented yet. In this review, we focused on the molecular changes associated with ccRCC development, along with gene expression and protein signatures, to emphasize the utilization of these molecular profiles in clinical practice. These findings, in the context of machine learning and precision medicine, may help to overcome some of the barriers encountered for implementing molecular profiles of tumors into the diagnosis and treatment of ccRCC.

The role of immunomodulatory metabolites in shaping the inflammatory response of macrophages

Macrophage activation has long been implicated in a myriad of human pathophysiology, particularly in the context of the dysregulated capacities of an unleashing intracellular or/and extracellular inflammatory response. A growing number of studies have functionally coupled the macrophages' inflammatory capacities with dynamic metabolic reprogramming which occurs during activation, albeit the results have been mostly interpreted through classic metabolism point of view; macrophages take advantage of the rewired metabolism as a source of energy and for biosynthetic precursors. However, a specific subset of metabolic products, namely immune-modulatory metabolites, has recently emerged as significant regulatory signals which control inflammatory responses in macrophages and the relevant extracellular milieu. In this review, we introduce recently highlighted immuno-modulatory metabolites, with the aim of understanding their physiological and pathological relevance in the macrophage inflammatory response. [BMB Reports 2022; 55(11): 519-527].

The Clinical and Molecular Features in the VHL Renal Cancers; Close or Distant Relatives with Sporadic Clear Cell Renal Cell Carcinoma?

Von Hippel-Lindau (VHL) disease is an autosomal dominant inherited cancer syndrome caused by germline mutations in the VHL tumor suppressor gene, characterized by the susceptibility to a wide array of benign and malign neoplasms, including clear-cell renal cell carcinoma. Moreover, VHL somatic inactivation is a crucial molecular event also in sporadic ccRCCs tumorigenesis. While systemic biomarkers in the VHL syndrome do not currently play a role in clinical practice, a new promising class of predictive biomarkers, microRNAs, has been increasingly studied. Lots of pan-genomic studies have deeply investigated the possible biological role of microRNAs in the development and progression of sporadic ccRCC; however, few studies have investigated the miRNA profile in VHL patients. Our review summarize all the new insights related to clinical and molecular features in VHL renal cancers, with a particular focus on the overlap with sporadic ccRCC.

VHL syndrome without clear family history: A rare case report and literature review of Chinese patients

Objective

To analyze the clinical manifestations and imaging features of a hospitalized patient with intermittent headache who was finally diagnosed with von Hippel–Lindau (VHL) syndrome and to perform whole-exon gene detection to improve the understanding of the diagnosis and treatment strategies of the disease.

Methods

A case of suspected VHL syndrome in Shanxi Provincial People's Hospital was analyzed. Proband DNA was also extracted for whole exome sequencing and screened for causative mutation sites, which were validated by Sanger sequencing. The literature about VHL gene mutations in Chinese patients in the past 10 years were also reviewed.

Results

There is a heterozygous mutation site c.499C > G on the VHL gene on the short arm of chromosome 3 of the patient, which is a missense mutation. The mutation results in the substitution of arginine with glycine at amino acid 167 of the encoded protein, which may be primarily responsible for the disease in the patient with VHL syndrome. However, the mutation did not occur in other family members.

Conclusion

Early recognition and treatment of VHL syndrome can be available with genetic testing technology. Strengthening the understanding of this complex genetic disease and improving the diagnostic rate of VHL syndrome are helpful for the precise treatment of patients with this disease, which may help prolong the survival time of patients to a certain extent and improve their quality of life.

Genetics of Pancreatic Neuroendocrine Tumors

Pancreatic neuroendocrine tumors (pNETs) represent a relatively rare disease; however, the incidence has been increasing during the last 2 decades. Next generation sequencing has greatly increased our understanding of driver mutations in pNETs. Sporadic pNETs have consistently presented with mutations in MEN1, DAXX/ATRX, and genes related to the mammalian target of rapamycin pathway. Inherited pNETs have traditionally been associated with multiple endocrine neoplasia type 1, von Hippel-Lindau syndrome, neurofibromatosis type 1, and tuberous sclerosis complex. The current review expands on the existing knowledge and the relevant updates on the genetics of pNETs.

Von Hippel–Lindau disease: insights into oxygen sensing, protein degradation, and cancer

Germline loss-of-function mutations of the VHL tumor suppressor gene cause von Hippel–Lindau disease, which is associated with an increased risk of hemangioblastomas, clear cell renal cell carcinomas (ccRCCs), and paragangliomas. This Review describes mechanisms involving the VHL gene product in oxygen sensing, protein degradation, and tumor development and current therapeutic strategies targeting these mechanisms. The VHL gene product is the substrate recognition subunit of a ubiquitin ligase that targets the α subunit of the heterodimeric hypoxia-inducible factor (HIF) transcription factor for proteasomal degradation when oxygen is present. This oxygen dependence stems from the requirement that HIFα be prolyl-hydroxylated on one (or both) of two conserved prolyl residues by members of the EglN (also called PHD) prolyl hydroxylase family. Deregulation of HIF, and particularly HIF2, drives the growth of VHL-defective ccRCCs. Drugs that inhibit the HIF-responsive gene product VEGF are now mainstays of ccRCC treatment. An allosteric HIF2 inhibitor was recently approved for the treatment of ccRCCs arising in the setting of VHL disease and has advanced to phase III testing for sporadic ccRCCs based on promising phase I/II data. Orally available EglN inhibitors are being tested for the treatment of anemia and ischemia. Five of these agents have been approved for the treatment of anemia in the setting of chronic kidney disease in various countries around the world.

Genotype–phenotype correlations and clinical outcomes of patients with von Hippel-Lindau disease with large deletions

Background

Approximately 20%–40% of patients with von Hippel-Lindau (VHL) disease, an autosomal dominant hereditary disease, exhibit large deletions (LDs). Few studies have focused on this population. Hence, we aimed to elucidate the genotype–phenotype correlations and clinical outcomes in VHL patients with LDs.

Methods

In this retrospective study, we included 119 patients with VHL disease from 50 unrelated families in whom LDs were detected using traditional and next-generation sequencing methods. Other germline mutations were confirmed by Sanger sequencing. Genotype–phenotype correlations and survival were analysed in different groups using Kaplan-Meier and Cox regression. We also evaluated therapeutic response to tyrosine kinase inhibitor (TKI) therapy.

Results

The overall penetrance of patients aged <60 was 95.2%. Two VHL patients with LDs also carried CHEK2 and FLCN germline mutations. An earlier age of onset of retinal haemangioblastoma was observed in the next generation. Patients with exon 2 deletion of VHL had an earlier onset age of renal cell carcinoma and pancreatic lesions. The risk of renal cell carcinoma was lower in VHL patients with LDs and a BRK1 deletion. The group with earlier age of onset received poorer prognosis. Four of eight (50%) patients showed partial response to TKI therapy.

Conclusion

The number of generations and the status of exon 2 could affect age of onset of VHL-related manifestations. Onset age was an independent risk factor for overall survival. TKI therapy was effective in VHL patients with LDs. Our findings would further support clinical surveillance and decision-making processes.

An oncogenic JMJD6-DGAT1 axis tunes the epigenetic regulation of lipid droplet formation in clear cell renal cell carcinoma

Characterized by intracellular lipid droplet accumulation, clear cell renal cell carcinoma (ccRCC) is resistant to cytotoxic chemotherapy and is a lethal disease. Through an unbiased siRNA screen of 2-oxoglutarate (2-OG)-dependent enzymes, which play a critical role in tumorigenesis, we identified Jumonji domain-containing 6 (JMJD6) as an essential gene for ccRCC tumor development. The downregulation of JMJD6 abolished ccRCC colony formation in vitro and inhibited orthotopic tumor growth in vivo. Integrated ChIP-seq and RNA-seq analyses uncovered diacylglycerol O-acyltransferase 1 (DGAT1) as a critical JMJD6 effector. Mechanistically, JMJD6 interacted with RBM39 and co-occupied DGAT1 gene promoter with H3K4me3 to induce DGAT1 expression. JMJD6 silencing reduced DGAT1, leading to decreased lipid droplet formation and tumorigenesis. The pharmacological inhibition (or depletion) of DGAT1 inhibited lipid droplet formation in vitro and ccRCC tumorigenesis in vivo. Thus, the JMJD6-DGAT1 axis represents a potential new therapeutic target for ccRCC.

Targeting HIF-1α by Natural and Synthetic Compounds: A Promising Approach for Anti-Cancer Therapeutics Development

Advancement in novel target detection using improved molecular cancer biology has opened up new avenues for promising anti-cancer drug development. In the past two decades, the mechanism of tumor hypoxia has become more understandable with the discovery of hypoxia-inducible factor-1α (HIF-1α). It is a major transcriptional regulator that coordinates the activity of various transcription factors and their downstream molecules involved in tumorigenesis. HIF-1α not only plays a crucial role in the adaptation of tumor cells to hypoxia but also regulates different biological processes, including cell proliferation, survival, cellular metabolism, angiogenesis, metastasis, cancer stem cell maintenance, and propagation. Therefore, HIF-1α overexpression is strongly associated with poor prognosis in patients with different solid cancers. Hence, pharmacological targeting of HIF-1α has been considered to be a novel cancer therapeutic strategy in recent years. In this review, we provide brief descriptions of natural and synthetic compounds as HIF-1α inhibitors that have the potential to accelerate anticancer drug discovery. This review also introduces the mode of action of these compounds for a better understanding of the chemical leads, which could be useful as cancer therapeutics in the future.

Diagnostic Strategies and Algorithms for Investigating Cancer Predisposition Syndromes in Children Presenting with Malignancy

Simple Summary

Here we provide an overview of several genetically determined conditions that predispose to the development of solid and hematologic malignancies in children. Diagnosing these conditions, whose prevalence is estimated around 10% in children with cancer, is useful to warrant personalized oncologic treatment and follow-up, as well as psychological and genetic counseling to these children and their families. We reviewed the most recent studies focusing on the prevalence of cancer predisposition syndromes in cancer-bearing children and the most-used clinical screening tools. Our work highlighted the value of clinical screening tools in the management of young cancer patients, especially in settings where genetic testing is not promptly accessible.

Abstract

In the past recent years, the expanding use of next-generation sequencing has led to the discovery of new cancer predisposition syndromes (CPSs), which are now known to be responsible for up to 10% of childhood cancers. As knowledge in the field is in constant evolution, except for a few “classic” CPSs, there is no consensus about when and how to perform germline genetic diagnostic studies in cancer-bearing children. Several clinical screening tools have been proposed to help identify the patients who carry higher risk, with heterogeneous strategies and results. After introducing the main clinical and molecular features of several CPSs predisposing to solid and hematological malignancies, we compare the available clinical evidence on CPS prevalence in pediatric cancer patients and on the most used decision-support tools in identifying the patients who could benefit from genetic counseling and/or direct genetic testing. This analysis highlighted that a personalized stepwise approach employing clinical screening tools followed by sequencing in high-risk patients might be a reasonable and cost-effective strategy in the care of children with cancer.

OTUB1 augments hypoxia signaling via its non-canonical ubiquitination inhibition of HIF-1α during hypoxia adaptation

As a main regulator of cellular responses to hypoxia, the protein stability of hypoxia-inducible factor (HIF)-1α is strictly controlled by oxygen tension dependent of PHDs-catalyzed protein hydroxylation and pVHL complex-mediated proteasomal degradation. Whether HIF-1α protein stability as well as its activity can be further regulated under hypoxia is not well understood. In this study, we found that OTUB1 augments hypoxia signaling independent of PHDs/VHL and FIH. OTUB1 binds to HIF-1α and depletion of OTUB1 reduces endogenous HIF-1α protein under hypoxia. In addition, OTUB1 inhibits K48-linked polyubiquitination of HIF-1α via its non-canonical inhibition of ubiquitination activity. Furthermore, OTUB1 promotes hypoxia-induced glycolytic reprogramming for cellular metabolic adaptation. These findings define a novel regulation of HIF-1α under hypoxia and demonstrate that OTUB1-mediated HIF-1α stabilization positively regulates HIF-1α transcriptional activity and benefits cellular hypoxia adaptation.

The Role of Propranolol as a Repurposed Drug in Rare Vascular Diseases

Rare Diseases (RD) are defined by their prevalence in less than 5 in 10,000 of the general population. Considered individually, each RD may seem insignificant, but together they add up to more than 7000 different diseases. Research in RD is not attractive for pharmaceutical companies since it is unlikely to recover development costs for medicines aimed to small numbers of patients. Since most of these diseases are life threatening, this fact underscores the urgent need for treatments. Drug repurposing consists of identifying new uses for approved drugs outside the scope of the original medical indication. It is an alternative option in drug development and represents a viable and risk-managed strategy to develop for RDs. In 2008, the “off label” therapeutic benefits of propranolol were described in the benign tumor Infantile Hemangioma. Propranolol, initially prescribed for high blood pressure, irregular heart rate, essential tremor, and anxiety, has, in the last decade, shown increasing evidence of its antiangiogenic, pro-apoptotic, vasoconstrictor and anti-inflammatory properties in different RDs, including vascular or oncological pathologies. This review highlights the finished and ongoing trials in which propranolol has arisen as a good repurposing drug for improving the health condition in RDs.

Role of mitochondrial reactive oxygen species in homeostasis regulation

Mitochondria are the main source of reactive oxygen species (ROS) in cells. Early studies have shown that mitochondrial reactive oxygen species (mROS) are related to the occurrence and adverse outcomes of many diseases, and are thus regarded as an important risk factor that threaten human health. Recently, increasing evidence has shown that mROS are very important for an organism’s homeostasis. mROS can regulate a variety of signaling pathways and activate the adaptation and protection behaviors of an organism under stress. In addition, mROS also regulate important physiological processes, such as cell proliferation, differentiation, aging, and apoptosis. Herein, we review the mechanisms of production, transformation, and clearance of mROS and their biological roles in different physiological processes.

The Role of VHL in the Development of von Hippel-Lindau Disease and Erythrocytosis

Von Hippel-Lindau disease (VHL disease or VHL syndrome) is a familial multisystem neoplastic syndrome stemming from germline disease-associated variants of the VHL tumor suppressor gene on chromosome 3. VHL is involved, through the EPO-VHL-HIF signaling axis, in oxygen sensing and adaptive response to hypoxia, as well as in numerous HIF-independent pathways. The diverse roles of VHL confirm its implication in several crucial cellular processes. VHL variations have been associated with the development of VHL disease and erythrocytosis. The association between genotypes and phenotypes still remains ambiguous for the majority of mutations. It appears that there is a distinction between erythrocytosis-causing VHL variations and VHL variations causing VHL disease with tumor development. Understanding the pathogenic effects of VHL variants might better predict the prognosis and optimize management of the patient.

Biostatistics of VHL-Gene Transfection in the Health Informatics Analysis of Renal Cell Carcinoma

Objective

In this paper, we study the role of the VHL gene in regulating the proliferation and apoptosis of renal cell carcinoma, as well as the safety and transfection efficiency of ultrasound microbubble gene transfection technology.

Method

We use kidney cancer cell lines as an in vitro research object and apply ultrasound microbubble gene transfection technology to transfect the VHL gene into kidney cancer cell line (786-0). The proliferation and apoptosis of cells were measured to clarify the inhibitory effect of the VHL gene in renal cell carcinoma. After that, pEGFP-VHL was transfected using ultrasonic microbubble and liposome gene transfection techniques, respectively, and the transfection efficiency was measured by immunofluorescence.

Results

Compared with untreated and 786-0 cells that are transfected with empty vector, the expression level of VHL gene mRNA in 786-0 cells that are transfected with pcDNA3.1-VHL was significantly increased, and the cell growth inhibition rate was significantly higher. The rate of apoptosis increased significantly. Transfection efficiency of the pEGFP-VHL gene after transfection of 786-0 cells for 48 h: control group 0, liposome group (35.55 ± 2.77) %, ultrasound microbubble group (18.27 ± 2.83) %, and two transfection methods on cells. There is no significant difference in the impact of vitality.

Conclusion

VHL gene expression can significantly inhibit the proliferation ability of renal cancer cell line 786-0 and promote its apoptosis. VHL gene is a potential target for gene therapy of kidney cancer.

Ubiquitin-specific peptidase 37: an important cog in the oncogenic machinery of cancerous cells

Protein ubiquitination is one of the most crucial posttranslational modifications responsible for regulating the stability and activity of proteins involved in homeostatic cellular function. Inconsistencies in the ubiquitination process may lead to tumorigenesis. Ubiquitin-specific peptidases are attractive therapeutic targets in different cancers and are being evaluated for clinical development. Ubiquitin-specific peptidase 37 (USP37) is one of the least studied members of the USP family. USP37 controls numerous aspects of oncogenesis, including stabilizing many different oncoproteins. Recent work highlights the role of USP37 in stimulating the epithelial-mesenchymal transition and metastasis in lung and breast cancer by stabilizing SNAI1 and stimulating the sonic hedgehog pathway, respectively. Several aspects of USP37 biology in cancer cells are yet unclear and are an active area of research. This review emphasizes the importance of USP37 in cancer and how identifying its molecular targets and signalling networks in various cancer types can help advance cancer therapeutics.

Lactate in the tumour microenvironment: From immune modulation to therapy

Disordered metabolic states, which are characterised by hypoxia and elevated levels of metabolites, particularly lactate, contribute to the immunosuppression in the tumour microenvironment (TME). Excessive lactate secreted by metabolism-reprogrammed cancer cells regulates immune responses via causing extracellular acidification, acting as an energy source by shuttling between different cell populations, and inhibiting the mechanistic (previously ‘mammalian’) target of rapamycin (mTOR) pathway in immune cells. This review focuses on recent advances in the regulation of immune responses by lactate, as well as therapeutic strategies targeting lactate anabolism and transport in the TME, such as those involving glycolytic enzymes and monocarboxylate transporter inhibitors. Considering the multifaceted roles of lactate in cancer metabolism, a comprehensive understanding of how lactate and lactate-targeting therapies regulate immune responses in the TME will provide insights into the complex relationships between metabolism and antitumour immunity.

Personalized First-Line Treatment of Metastatic Pancreatic Neuroendocrine Carcinoma Facilitated by Liquid Biopsy and Computational Decision Support

BACKGROUND

We present the case of a 50-year-old female whose metastatic pancreatic neuroendocrine tumor (pNET) diagnosis was delayed by the COVID-19 pandemic. The patient was in critical condition at the time of diagnosis due to the extensive tumor burden and failing liver functions. The clinical dilemma was to choose between two registered first-line molecularly-targeted agents (MTAs), sunitinib or everolimus, or to use chemotherapy to quickly reduce tumor burden.

METHODS

Cell-free DNA (cfDNA) from liquid biopsy was analyzed by next generation sequencing (NGS) using a comprehensive 591-gene panel. Next, a computational method, digital drug-assignment (DDA) was deployed for rapid clinical decision support.

RESULTS

NGS analysis identified 38 genetic alterations. DDA identified 6 potential drivers, 24 targets, and 79 MTAs. Everolimus was chosen for first-line therapy based on supporting molecular evidence and the highest DDA ranking among therapies registered in this tumor type. The patient's general condition and liver functions rapidly improved, and CT control revealed partial response in the lymph nodes and stable disease elsewhere.

CONCLUSION

Deployment of precision oncology using liquid biopsy, comprehensive molecular profiling, and DDA make personalized first-line therapy of advanced pNET feasible in clinical settings.

Roxadustat (FG-4592) prevents Ang II hypertension by targeting angiotensin receptors and eNOS

The prevalence of hypertension is increasing globally, while strategies for prevention and treatment of hypertension remain limited. FG-4592 (Roxadustat) is a potentially novel, orally active small-molecule hypoxia-inducible factor (HIF) stabilizer and is being used clinically to treat chronic kidney disease (CKD) anemia. In the present study, we evaluate the effects of FG-4592 on hypertension. In an angiotensin II (Ang II) hypertension model, FG-4592 abolished hypertensive responses; prevented vascular thickening, cardiac hypertrophy, and kidney injury; downregulated AGTR1 expression; and enhanced AGTR2, endothelial NO synthase (eNOS), and HIF1α protein levels in the aortas of mice. Additionally, the levels of thiobarbituric acid reactive substances (TBARs) in blood and urine were diminished by FG-4592 treatment. In vascular smooth muscle cells, FG-4592 treatment reduced angiotensin receptor type 1 (AGTR1) and increased AGTR2 levels, while preventing Ang II–induced oxidative stress. In vascular endothelial cells, FG-4592 upregulated total and phosphorylated eNOS. Moreover, FG-4592 treatment was hypotensive in L-NAME–induced hypertension. In summary, FG-4592 treatment remarkably ameliorated hypertension and organ injury, possibly through stabilizing HIF1α and subsequently targeting eNOS, AGTR1, AGTR2, and oxidative stress. Therefore, in addition to its role in treating CKD anemia, FG-4592 could be explored as a treatment for hypertension associated with high renin angiotensin system (RAS) activity or eNOS defects.

Von Hippel-Lindau tumor suppressor pathways & corresponding therapeutics in kidney cancer

The identification and application of the Von Hippel-Lindau (VHL) gene is a seminal breakthrough in kidney cancer research. VHL and its protein pVHL are the root cause of most kidney cancers, and the cascading pathway below them is crucial for understanding hypoxia, in addition to the aforementioned tumorigenesis routes and treatments. We reviewed the history and functions of VHL/pVHL and Hypoxia-inducible factor (HIF), their well-known activities under low-oxygen environments as an E3 ubiquitin ligase and as a transcription factor, respectively, as well as their non-canonical functions revealed recently. Additionally, we discussed how their dysregulation promotes tumorigenesis: beginning with chromosome 3 p-arm (3p) loss/epigenetic methylation, followed by two-allele knockout, before the loss of complimentary tumor suppressor genes leads cells down predictable oncological paths. These different pathways can ultimately determine the grade, outcome, and severity of the deadliest genitourinary cancer. We finished by investigating current and proposed schemes to therapeutically treat clear cell renal cell carcinoma (ccRCC) by manipulating the hypoxic pathway utilizing Vascular Endothelial Growth Factor (VEGF) inhibitors, mammalian target of rapamycin complex 1 (mTORC1) inhibitors, small molecule HIF inhibitors, immune checkpoint blockade therapy, and synthetic lethality.

INTRAVITREAL INJECTION OF PROPRANOLOL FOR THE TREATMENT OF RETINAL CAPILLARY HEMANGIOMA IN A CASE OF VON HIPPEL-LINDAU

PURPOSE

The purpose of this study was to evaluate the safety and efficacy of intravitreal propranolol for the management of retinal capillary hemangioma in a patient with Von Hippel-Lindau.

METHODS

Two intravitreal injections of 50 μg/0.05 mL propranolol were administered 6 weeks apart in the left eye of a 26-year-old patient with bilateral multiple retinal capillary hemangiomas. Safety and response to therapy were evaluated using electroretinogram, fluorescein angiography, and measurement of visual acuity. Laser photocoagulation was performed in the right eye.

RESULTS

One month after the second intravitreal injection of propranolol, fluorescein leakage decreased from the tumors located on the optic nerve head and in the inferonasal retinal periphery. Reduction of the retinal capillary hemangioma vascularity and enhancement of its fibrosis associated with the attenuation of the feeder vessel were also observed. Ophthalmic examination showed no adverse effect except for a mild transient vitreous haziness after each injection. Electroretinogram performed 4 weeks after the first injection revealed no retinal toxicity.

CONCLUSION

Intravitreal propranolol showed a therapeutic effect on retinal capillary hemangioma with no short-term adverse effects except a mild transient inflammatory response in a patient with Von Hippel-Lindau.

Ubiquitin ligases in cancer: Functions and clinical potentials

Ubiquitylation, a highly regulated post-translational modification, controls many cellular pathways that are critical to cell homeostasis. Ubiquitin ligases recruit substrates and promote ubiquitin transfer onto targets, inducing proteasomal degradation or non-degradative signaling. Accumulating evidence highlights the critical role of dysregulated ubiquitin ligases in processes associated with the initiation and progression of cancer. Depending on the substrate specificity and biological context, a ubiquitin ligase can act either as a tumor promoter or as a tumor suppressor. In this review, we focus on the regulatory roles of ubiquitin ligases and how perturbations of their functions contribute to cancer pathogenesis. We also briefly discuss current strategies for targeting or exploiting ubiquitin ligases for cancer therapy.