VHL suppresses autophagy and tumor growth through PHD1-dependent Beclin1 hydroxylation.

The Von Hippel-Lindau (VHL) protein, which is frequently mutated in clear-cell renal cell carcinoma (ccRCC), is a master regulator of hypoxia-inducible factor (HIF) that is involved in oxidative stresses. However, whether VHL possesses HIF-independent tumor-suppressing activity remains largely unclear. Here, we demonstrate that VHL suppresses nutrient stress-induced autophagy, and its deficiency in sporadic ccRCC specimens is linked to substantially elevated levels of autophagy and correlates with poorer patient prognosis. Mechanistically, VHL directly binds to the autophagy regulator Beclin1, after its PHD1-mediated hydroxylation on Pro54. This binding inhibits the association of Beclin1-VPS34 complexes with ATG14L, thereby inhibiting autophagy initiation in response to nutrient deficiency. Expression of non-hydroxylatable Beclin1 P54A abrogates VHL-mediated autophagy inhibition and significantly reduces the tumor-suppressing effect of VHL. In addition, Beclin1 P54-OH levels are inversely correlated with autophagy levels in wild-type VHL-expressing human ccRCC specimens, and with poor patient prognosis. Furthermore, combined treatment of VHL-deficient mouse tumors with autophagy inhibitors and HIF2α inhibitors suppresses tumor growth. These findings reveal an unexpected mechanism by which VHL suppresses tumor growth, and suggest a potential treatment for ccRCC through combined inhibition of both autophagy and HIF2α.

FBXL4 ubiquitin ligase deficiency promotes mitophagy by elevating NIX levels.

Selective autophagy of mitochondria, mitophagy, is linked to mitochondrial quality control and as such is critical to a healthy organism. We have used a CRISPR/Cas9 approach to screen human E3 ubiquitin ligases for influence on mitophagy under both basal cell culture conditions and upon acute mitochondrial depolarization. We identify two cullin-RING ligase substrate receptors, VHL and FBXL4, as the most profound negative regulators of basal mitophagy. We show that these converge, albeit via different mechanisms, on control of the mitophagy adaptors BNIP3 and BNIP3L/NIX. FBXL4 restricts NIX and BNIP3 levels via direct interaction and protein destabilization, while VHL acts through suppression of HIF1α-mediated transcription of BNIP3 and NIX. Depletion of NIX but not BNIP3 is sufficient to restore mitophagy levels. Our study contributes to an understanding of the aetiology of early-onset mitochondrial encephalomyopathy that is supported by analysis of a disease-associated mutation. We further show that the compound MLN4924, which globally interferes with cullin-RING ligase activity, is a strong inducer of mitophagy, thus providing a research tool in this context and a candidate therapeutic agent for conditions linked to mitochondrial dysfunction.

E3 Ligase VHL Promotes Group 2 Innate Lymphoid Cell Maturation and Function via Glycolysis Inhibition and Induction of Interleukin-33 Receptor.

Group 2 innate lymphoid cells (ILC2s) are a specialized subset of lymphoid effector cells that are critically involved in allergic responses; however, the mechanisms of their regulation remain unclear. We report that conditional deletion of the E3 ubiquitin ligase VHL in innate lymphoid progenitors minimally affected early-stage bone marrow ILC2s but caused a selective and intrinsic decrease in mature ILC2 numbers in peripheral non-lymphoid tissues, resulting in reduced type 2 immune responses. VHL deficiency caused the accumulation of hypoxia-inducible factor 1α (HIF1α) and attenuated interleukin-33 (IL-33) receptor ST2 expression, which was rectified by HIF1α ablation or inhibition. HIF1α-driven expression of the glycolytic enzyme pyruvate kinase M2 downmodulated ST2 expression via epigenetic modification and inhibited IL-33-induced ILC2 development. Our study indicates that the VHL-HIF-glycolysis axis is essential for the late-stage maturation and function of ILC2s via targeting IL-33-ST2 pathway.

Characterizing and predicting ccRCC-causing missense mutations in Von Hippel-Lindau disease.

BACKGROUND: Mutations within the Von Hippel-Lindau (VHL) tumor suppressor gene are known to cause VHL disease, which is characterized by the formation of cysts and tumors in multiple organs of the body, particularly clear cell renal cell carcinoma (ccRCC). A major challenge in clinical practice is determining tumor risk from a given mutation in the VHL gene. Previous efforts have been hindered by limited available clinical data and technological constraints. METHODS: To overcome this, we initially manually curated the largest set of clinically validated VHL mutations to date, enabling a robust assessment of existing predictive tools on an independent test set. Additionally, we comprehensively characterized the effects of mutations within VHL using in silico biophysical tools describing changes in protein stability, dynamics and affinity to binding partners to provide insights into the structure-phenotype relationship. These descriptive properties were used as molecular features for the construction of a machine learning model, designed to predict the risk of ccRCC development as a result of a VHL missense mutation. RESULTS: Analysis of our model showed an accuracy of 0.81 in the identification of ccRCC-causing missense mutations, and a Matthew's Correlation Coefficient of 0.44 on a non-redundant blind test, a significant improvement in comparison to the previous available approaches. CONCLUSION: This work highlights the power of using protein 3D structure to fully explore the range of molecular and functional consequences of genomic variants. We believe this optimized model will better enable its clinical implementation and assist guiding patient risk stratification and management.

FOXA2 activates HIF2α expression to promote tumor progression and is regulated by the E3 ubiquitin ligase VHL in renal cell carcinoma.

Renal cell carcinoma (RCC) is a frequent malignancy of the urinary system with high mortality and morbidity. However, the molecular mechanisms underlying RCC progression are still largely unknown. In this study, we identified FOXA2, a pioneer transcription factor, as a driver oncogene for RCC. We show that FOXA2 was commonly upregulated in human RCC samples and promoted RCC proliferation, as evidenced by assays of cell viability, colony formation, migratory and invasive capabilities, and stemness properties. Mechanistically, we found that FOXA2 promoted RCC cell proliferation by transcriptionally activating HIF2α expression in vitro and in vivo. Furthermore, we found that FOXA2 could interact with VHL (von Hippel‒Lindau), which ubiquitinated FOXA2 and controlled its protein stability in RCC cells. We showed that mutation of lysine at position 264 to arginine in FOXA2 could mostly abrogate its ubiquitination, augment its activation effect on HIF2α expression, and promote RCC proliferation in vitro and RCC progression in vivo. Importantly, elevated expression of FOXA2 in patients with RCC positively correlated with the expression of HIF2α and was associated with shorter overall and disease-free survival. Together, these findings reveal a novel role of FOXA2 in RCC development and provide insights into the underlying molecular mechanisms of FOXA2-driven pathological processes in RCC.

Induction of DEPP1 by HIF Mediates Multiple Hallmarks of Ischemic Cardiomyopathy.

BACKGROUND: HIF (hypoxia inducible factor) regulates many aspects of cardiac function. We and others previously showed that chronic HIF activation in the heart in mouse models phenocopies multiple features of ischemic cardiomyopathy in humans, including mitochondrial loss, lipid accumulation, and systolic cardiac dysfunction. In some settings, HIF also causes the loss of peroxisomes. How, mechanistically, HIF promotes cardiac dysfunction is an open question. METHODS: We used mice lacking cardiac pVHL (von Hippel-Lindau protein) to investigate how chronic HIF activation causes multiple features of ischemic cardiomyopathy, such as autophagy induction and lipid accumulation. We performed immunoblot assays, RNA sequencing, mitochondrial and peroxisomal autophagy flux measurements, and live cell imaging on hearts and isolated cardiomyocytes. We used CRISPR-Cas9 gene editing in mice to validate a novel mediator of cardiac dysfunction in the setting of chronic HIF activation. RESULTS: We identify a previously unknown pathway by which cardiac HIF activation promotes the loss of mitochondria and peroxisomes. We found that DEPP1 (decidual protein induced by progesterone 1) is induced under hypoxia in a HIF-dependent manner and localizes inside mitochondria. DEPP1 is both necessary and sufficient for hypoxia-induced autophagy and triglyceride accumulation in cardiomyocytes ex vivo. DEPP1 loss increases cardiomyocyte survival in the setting of chronic HIF activation ex vivo, and whole-body Depp1 loss decreases cardiac dysfunction in hearts with chronic HIF activation caused by VHL loss in vivo. CONCLUSIONS: Our findings identify DEPP1 as a key component in the cardiac remodeling that occurs with chronic ischemia.

Mosaicism in Tumor Suppressor Gene Syndromes: Prevalence, Diagnostic Strategies, and Transmission Risk.

A mosaic state arises when pathogenic variants are acquired in certain cell lineages during postzygotic development, and mosaic individuals may present with a generalized or localized phenotype. Here, we review the current state of knowledge regarding mosaicism for eight common tumor suppressor genes-NF1, NF2, TSC1, TSC2, PTEN, VHL, RB1, and TP53-and their related genetic syndromes/entities. We compare and discuss approaches for comprehensive diagnostic genetic testing, the spectrum of variant allele frequency, and disease severity. We also review affected individuals who have no mutation identified after conventional genetic analysis, as well as genotype-phenotype correlations and transmission risk for each tumor suppressor gene in full heterozygous and mosaic patients. This review provides new insight into similarities as well as marked differences regarding the appreciation of mosaicism in these tumor suppressor syndromes.

Sensitivity of VHL mutant kidney cancers to HIF2 inhibitors does not require an intact p53 pathway.

Inactivation of the VHL tumor suppressor gene is the signature initiating event in clear cell renal cell carcinoma (ccRCC), which is the most common form of kidney cancer. The VHL tumor suppressor protein marks hypoxia-inducible factor 1 (HIF1) and HIF2 for proteasomal degradation when oxygen is present. The inappropriate accumulation of HIF2 drives tumor formation by VHL tumor suppressor protein (pVHL)­defective ccRCC. Belzutifan, a first-in-class allosteric HIF2 inhibitor, has advanced to phase 3 testing for advanced ccRCC and is approved for ccRCCs arising in patients with VHL disease, which is caused by germline VHL mutations. HIF2 can suppress p53 function in some settings and preliminary data suggested that an intact p53 pathway, as measured by activation in response to DNA damage, was necessary for HIF2 dependence. Here, we correlated HIF2 dependence and p53 status across a broader collection of ccRCC cell lines. We also genetically manipulated p53 function in ccRCC lines that were or were not previously HIF2-dependent and then assessed their subsequent sensitivity to HIF2 ablation using CRISPR-Cas9 or the HIF2 inhibitor PT2399, which is closely related to belzutifan. From these studies, we conclude that p53 status does not dictate HIF2 dependence, at least in preclinical models, and thus is unlikely to be a useful biomarker for predicting which ccRCC patients will respond to HIF2 inhibitors.

Radiogenomics and Texture Analysis to Detect von Hippel-Lindau (VHL) Mutation in Clear Cell Renal Cell Carcinoma.

Radiogenomics, a burgeoning field in biomedical research, explores the correlation between imaging features and genomic data, aiming to link macroscopic manifestations with molecular characteristics. In this review, we examine existing radiogenomics literature in clear cell renal cell carcinoma (ccRCC), the predominant renal cancer, and von Hippel-Lindau (VHL) gene mutation, the most frequent genetic mutation in ccRCC. A thorough examination of the literature was conducted through searches on the PubMed, Medline, Cochrane Library, Google Scholar, and Web of Science databases. Inclusion criteria encompassed articles published in English between 2014 and 2022, resulting in 10 articles meeting the criteria out of 39 initially retrieved articles. Most of these studies applied computed tomography (CT) images obtained from open source and institutional databases. This literature review investigates the role of radiogenomics, with and without texture analysis, in predicting VHL gene mutation in ccRCC patients. Radiogenomics leverages imaging modalities such as CT and magnetic resonance imaging (MRI), to analyze macroscopic features and establish connections with molecular elements, providing insights into tumor heterogeneity and biological behavior. The investigations explored diverse mutations, with a specific focus on VHL mutation, and applied CT imaging features for radiogenomic analysis. Moreover, radiomics and machine learning techniques were employed to predict VHL gene mutations based on CT features, demonstrating promising results. Additional studies delved into the relationship between VHL mutation and body composition, revealing significant associations with adipose tissue distribution. The review concludes by highlighting the potential role of radiogenomics in guiding targeted and selective therapies.

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.

Vascular, adipose tissue, and/or calyceal invasion in clear cell tubulopapillary renal cell tumour: potentially problematic diagnostic scenarios.

AIMS: The 2022 WHO classification for kidney tumours recently downgraded clear cell tubulopapillary (also known as clear cell papillary) renal cell carcinoma (RCC) to a benign neoplasm (i.e. clear cell tubulopapillary renal cell tumour) based on the overwhelmingly banal nature of this neoplasm. However, it has been recognized that some clear cell tubulopapillary renal cell tumours demonstrate vascular, adipose or pelvicalyceal invasion, raising the possibility of more aggressive behaviour. The goal of this study was to determine if these 'high stage' features have an effect on tumour prognosis, warranting a carcinoma designation. METHODS AND RESULTS: After excluding cases with tissue artefact (i.e. prior core biopsy track changes) and other RCC subtypes with next-generation sequencing, nine clear cell tubulopapillary renal cell tumours with these so-called 'high stage' features, and otherwise classic morphologic and immunophenotypic findings, including low-grade cytology and 'cup-like' CA9 expression, were evaluated. Median tumour size was 2.2 cm with a range of 0.8 to 6.7 cm. Eight cases (89%) demonstrated perinephric or hilar adipose tissue invasion, although most of these cases showed a bulging (in contrast to an infiltrative) growth pattern. One case demonstrated renal vascular invasion in addition to hilar adipose tissue invasion, and one case demonstrated extension into the pelvicalyceal system. There were no recurrences or evidence of metastatic disease. CONCLUSION: These overall findings continue to support the benign designation for clear cell tubulopapillary renal cell tumours, despite morphologic features that might raise the possibility of a 'higher stage' neoplasm.

Stereochemical inversion at a 1,4-cyclohexyl PROTAC linker fine-tunes conformation and binding affinity.

Proteolysis targeting chimeras (PROTACs) are heterobifunctional small-molecule degraders made of a linker connecting a target-binding moiety to a ubiquitin E3 ligase-binding moiety. The linker unit is known to influence the physicochemical and pharmacokinetic properties of PROTACs, as well as the properties of ternary complexes, in turn impacting on their degradation activity in cells and in vivo. Our LRRK2 PROTAC XL01126, bearing a trans-cyclohexyl group in the linker, is a better and more cooperative degrader than its corresponding cis- analogue despite its much weaker binary binding affinities. Here, we investigate how this subtle stereocenter alteration in the linker affects the ligand binding affinity to the E3 ligase VHL. We designed a series of molecular matched pairs, truncating from the full PROTACs down to the VHL ligand, and find that across the series the trans-cyclohexyl compounds showed consistently weaker VHL-binding affinity compared to the cis- counterparts. High-resolution co-crystal structures revealed that the trans linker exhibits a rigid stick-out conformation, while the cis linker collapses into a folded-back conformation featuring a network of intramolecular contacts and long-range interactions with VHL. These observations are noteworthy as they reveal how a single stereochemical inversion within a PROTAC linker impacts conformational rigidity and binding mode, in turn fine-tuning differentiated propensity to binary and ternary complex formation, and ultimately cellular degradation activity.

Expanding the ligand spaces for E3 ligases for the design of protein degraders.

Targeted protein degradation (TPD) has recently emerged as an exciting new drug modality. However, the strategy of developing small molecule-based protein degraders has evolved over the past two decades and has now established molecular tags that are already in clinical use, as well as chimeric molecules, PROteolysis TArgeting Chimeras (PROTACs), based mainly on ligand systems developed for the two E3 ligases CRBN and VHL. The large size of the human E3 ligase family suggests that PROTACs can be developed by targeting a large diversity of E3 ligases, some of which have restricted expression patterns with the potential to design disease- or tissue-specific degraders. Indeed, many new E3 ligands have been published recently, confirming the druggability of E3 ligases. This review summarises recent data on E3 ligases and highlights the challenges in developing these molecules into efficient PROTACs rivalling the established degrader systems.

Percutaneous microwave ablation on management of hereditary renal cell carcinoma in Von Hippel-Lindau disease.

BACKGROUND: The effect of microwave ablation (MWA) for the renal cell carcinoma (RCC) in Von Hippel-Lindau (VHL) disease is unclear. OBJECTIVE: To assess the safety, Technique efficacy, renal function and oncological outcome of MWA for RCC in VHL patients. METHODS: Consecutive patients with RCCs in VHL disease treated by MWA were retrospectively collected from November 2009 to October 2020. The technical efficacy rate and complications were assessed. The outcomes of pre- and post-ablative eGFR were compared. The local recurrent-free survival (LRFS), renal-cancer-free survival (RCFS), cancer-specific survival (CSS), overall survival (OS) and complications were presented. RESULTS: A total of 10 patients (mean age, 39.0 years ± 10.7 [SD]; 3 women) with 28 RCCs (mean tumor size, 3.0 cm ± 0.34; mean tumor volume, 20.7 mL ± 43.3) treated with MWA were included. Th median follow-up time was 52 months(IQR:27-80). The overall technical efficacy rate was 100% with no major complications occurred. No significant statistical difference between pre-ablative and postablative creatinine level (102.0 µmol/L ± 30.4 vs 112.3 µmol/L ± 38.7, p = 0.06), but the pre-ablative eGFR level was significantly higher than the post-ablative eGFR (78.0 mL/(min*1.73m2) ± 28.6 vs 72 mL/(min*1.73m2) ± 31.4, p = 0.04), with the mean decrease of 5.86 ml/(min*1.73m2). The local recurrent-free survival(LRFS) and renal-cancer-free survival (RCFS) were 100% and 60%, respectively. The cancer specifical survival (CSS) and overall survival (OS) were 95.5% and 100%, respectively. CONCLUSION: Microwave ablation is a safe and feasible method for the treatment of RCC in VHL disease, preserving renal function and yielding satisfactory oncological outcomes.

Development of VHL-recruiting STING PROTACs that suppress innate immunity.

STING acts as a cytosolic nucleotide sensor to trigger host defense upon viral or bacterial infection. While STING hyperactivation can exert anti-tumor effects by increasing T cell filtrates, in other contexts hyperactivation of STING can contribute to autoimmune and neuroinflammatory diseases. Several STING targeting agonists and a smaller subset of antagonists have been developed, yet STING targeted degraders, or PROTACs, remain largely underexplored. Here, we report a series of STING-agonist derived PROTACs that promote STING degradation in renal cell carcinoma (RCC) cells. We show that our STING PROTACs activate STING and target activated/phospho-STING for degradation. Locking STING on the endoplasmic reticulum via site-directed mutagenesis disables STING translocation to the proteasome and resultingly blocks STING degradation. We also demonstrate that PROTAC treatment blocks downstream innate immune signaling events and attenuates the anti-viral response. Interestingly, we find that VHL acts as a bona fide E3 ligase for STING in RCC; thus, VHL-recruiting STING PROTACs further promote VHL-dependent STING degradation. Our study reveals the design and biological assessment of VHL-recruiting agonist-derived STING PROTACs, as well as demonstrates an example of hijacking a physiological E3 ligase to enhance target protein degradation via distinct mechanisms.

The genetic differences between types 1 and 2 in von Hippel-Lindau syndrome: comprehensive meta-analysis.

BACKGROUND: Patients with von Hippel-Lindau (VHL) disease are at risk of developing tumors in the eye, brain, kidney, adrenal gland, and other organs based on their gene mutations. The VHL tumor suppressor gene contains pathogenic variants responsible for these events. This meta-analysis aims to investigate the genetic differences among the various types of VHL syndrome and their correlation with the location of mutations (exons and domains) in the VHL gene. METHOD: Papers eligible for publication until September 2023 were identified using the electronic databases of PubMed, Google Scholar, Scopus, and EMBASE. The Random Effect model was utilized to evaluate the genetic differences between type 1 and type 2 VHL syndromes. RESULTS: The prevalence of missense mutations (MSs) was found to be 58.9% in type 1, while it was 88.1% in type 2. Interestingly, the probability of observing MSs in type 1 was 0.42 times lower compared to type 2. The mutation hotspots of the VHL gene were R167Q/W, Y98H, R238W, and S65L, respectively. Although type 2 had a high presentation of Y98H and R238W, it did not have a higher S65L than type 1. The analysis demonstrated a statistically significant higher prevalence of truncated mutations (PTMs) in type 1. Among type 1, large/complete deletions (L/C DELs) were found in 16.9% of cases, whereas in type 2 only 3.7%. This difference was statistically significant with a p-value < 0.001. Overall, the probability of identifying mutations in domain 2 compared to domain 1 was found to be 2.13 times higher in type 1 (p-value < 0.001). Furthermore, the probability of detecting exon 1 in comparison with observing exon 2 in type 1 was 2.11 times higher than type 2 and revealed a statistically significant result (p-value < 0.001). The detection of exon 2 was 2.18 times higher in type 1 (p-value < 0.001). In addition, the likelihood of discovering exon 2 compared with others was significantly lower in type 1 compared with type 2 VHL (OR = 0.63, p-value = 0.015). CONCLUSIONS: We have revealed a comprehensive genetic difference between types 1 and 2 of VHL syndrome. The significant differences in MS, PTMs, L/C DELs, and the location of the mutations between type 1 and type 2 VHL patients in the Asian, European, and American populations emphasize the genetic heterogeneity of the syndrome. These findings may pave the way for the diagnosis, treatment, and further investigation of the mechanisms behind this complex genetic disorder.

von Hippel-Lindau disease-related neoplasia with an emphasis on renal manifestations.

von Hippel-Lindau (VHL) disease is characterized by biallelic inactivation of the VHL gene leading to abnormal or absent VHL protein function, and constitutive activation of hypoxia-inducible factors (HIF) that leads to pro-tumorigenic signaling. Individuals with VHL disease develop numerous cysts and tumors involving multiple organs including the kidneys, central nervous system, endolymphatic sac, lungs, pancreatobiliary system, adrenal glands, epididymis, and/or broad ligament. On histologic examination, these lesions show morphologic overlap as they are frequently characterized by cells with clear cytoplasm and prominent vascularity. In addition to distinguishing non-renal tumors from metastatic clear cell renal cell carcinoma, understanding site-specific histopathologic and immunophenotypic features of these tumors has several applications. This includes distinguishing VHL-related tumors from those that arise sporadically and lack VHL gene alterations, guiding further genetic workup, and helping distinguish between different genetic predisposition syndromes. In this context, immunohistochemical studies for markers such as paired box 8 (PAX-8), carbonic anhydrase 9 (CA9), and glucose transporter 1 (GLUT-1) have an important role in routine clinical practice and represent cost-effective diagnostic tools. The recent development of targeted therapeutics directed against HIF-mediated signaling represents a significant milestone in the management of VHL disease and highlights the importance of accurately diagnosing and characterizing the wide spectrum of VHL disease-associated lesions.

Evaluation of the diagnostic utility of NCOA3, Maspin and VHL protein expression in pancreatic ductal adenocarcinoma: An immunohistochemical study.

Pancreatic ductal adenocarcinoma (PDAC) is a lethal tumor with a high mortality rate. The distinction between PDAC and chronic pancreatitis is sometimes challenging on routine histopathological examination, highlighting the need to identify biomarkers that can facilitate this distinction. This retrospective study was conducted to evaluate the diagnostic utility of nuclear receptor co-activator 3 (NCOA3), Maspin and Von Hippel-Lindau protein (VHL) immunostaining in PDAC. Eighty cases of PDAC, 46 cases of chronic pancreatitis and 53 normal pancreatic tissue were immunohistochemically assessed using NCOA3, Maspin and VHL antibodies on sections from a tissue microarray. NCOA3, Maspin and VHL were positive in 90 %, 100 % and 35 %, of PDAC cases respectively, whereas NCOA3, Maspin and VHL expressions were positive in 3.8 %, 0 and 100 % of normal pancreatic tissue and in 15.2 %, 21.7 % and 97.8 % of chronic pancreatitis cases respectively. Significant differences were observed between PDAC and other groups regarding NCOA3, Maspin and VHL expression (p < 0.001). The H scores of NCOA3, Maspin and VHL could significantly distinguish between PDAC and normal cases with high sensitivity (90 %, 100 % and 98.75 % respectively) and specificity (100 %, 100 % and 96.23 % respectively). Similar findings were found in the distinction between PDAC and chronic pancreatitis (Sensitivity: 90 %, 95.25 % and 98.75 %; specificity: 100 %, 100 % and 93.48 % for NCOA3, Maspin and VHL respectively). In conclusion, NCOA3 and Maspin were found to be significantly expressed in PDAC compared to non-tumorous tissue while VHL was significantly expressed in non-tumorous tissue. A panel of NCOA3, Maspin and VHL could potentially distinguish PDAC from non-tumorous pancreatic tissue.

The Role of the PAX Genes in Renal Cell Carcinoma.

Renal cell carcinoma (RCC) is a significant oncological challenge due to its heterogeneous nature and limited treatment options. The PAX developmental gene family encodes nine highly conserved transcription factors that play crucial roles in embryonic development and organogenesis, which have been implicated in the occurrence and development of RCC. This review explores the molecular landscape of RCC, with a specific focus on the role of the PAX gene family in RCC tumorigenesis and disease progression. Of the various RCC subtypes, clear cell renal cell carcinoma (ccRCC) is the most prevalent, characterized by the loss of the von Hippel-Lindau (VHL) tumor suppressor gene. Here, we review the published literature on the expression patterns and functional implications of PAX genes, particularly PAX2 and PAX8, in the three most common RCC subtypes, including ccRCC, papillary RCC (PRCC), and chromophobe RCC (ChRCC). Further, we review the interactions and potential biological mechanisms involving PAX genes and VHL loss in driving the pathogenesis of RCC, including the key signaling pathways mediated by VHL in ccRCC and associated mechanisms implicating PAX. Lastly, concurrent with our update regarding PAX gene research in RCC, we review and comment on the targeting of PAX towards the development of novel RCC therapies.

Integrating Proteomics and Transcriptomics Reveals the Potential Pathways of Hippocampal Neuron Apoptosis in Dravet Syndrome Model Mice.

An important component contributing to the onset of epilepsy is the death of hippocampal neurons. Several studies have shown that Dravet syndrome model mice: Scn1a KO mice have a high number of apoptotic neurons following seizures, but the precise mechanism underlying this remains unclear. The aim of this research was to elucidate the potential molecular mechanism of neuronal apoptosis in Scn1a KO mice by integrating proteomics and transcriptomics, with the ultimate goal of offering better neuroprotection. We found that apoptotic processes were enriched in both proteomic and transcriptomic GO analyses, and KEGG results also indicated that differential proteins and genes play a role in neurotransmission, the cell cycle, apoptosis, and neuroinflammation. Then, we examined the upstream and downstream KGML interactions of the pathways to determine the relationship between the two omics, and we found that the HIF-1 signaling pathway plays a significant role in the onset and apoptosis of epilepsy. Meanwhile, the expression of the apoptosis-related protein VHL decreased in this pathway, and the expression of p21 was upregulated. Therefore, this study suggests that VHL/HIF-1α/p21 might be involved in the apoptosis of hippocampal neurons in Scn1a KO mice.