FDA Approval Summary: Belzutifan for von Hippel-Lindau Disease-Associated Tumors

HIF-1 and HIF-2 in cancer: structure, regulation, and therapeutic prospects

Hypoxia, or a state of low tissue oxygenation, has been characterized as an important feature of solid tumors that is related to aggressive phenotypes. The cellular response to hypoxia is controlled by Hypoxia-inducible factors (HIFs), a family of transcription factors. HIFs promote the transcription of gene products that play a role in tumor progression including proliferation, angiogenesis, metastasis, and drug resistance. HIF-1 and HIF-2 are well known and widely described. Although these proteins share a high degree of homology, HIF-1 and HIF-2 have non-redundant roles in cancer. In this review, we summarize the similarities and differences between HIF-1α and HIF-2α in their structure, expression, and DNA binding. We also discuss the canonical and non-canonical regulation of HIF-1α and HIF-2α under hypoxic and normal conditions. Finally, we outline recent strategies aimed at targeting HIF-1α and/or HIF-2α.

Pediatric patients with von Hippel-Lindau and hemangioblastomas treated successfully with belzutifan

Hemangioblastoma is the most common tumor associated with von Hippel-Lindau (VHL), and are a leading cause of mortality. We present five pediatric patients with VHL-associated hemangioblastomas treated with belzutifan, a hypoxia-inducible factor 2a (HIF2a) inhibitor. Three patients were started on belzutifan due to vision loss from progressive retinal hemangioblastomas. Within one year of treatment, all three patients had improvement in hemangioblastoma size and visual acuity. For patients with intracranial lesions, belzutifan resulted in an improvement in neurologic symptoms and hemangioblastoma size. Four patients experienced grade 1-2 anemia and two patients required a dose reduction. Our report suggests that belzutifan can be an effective therapy for pediatric, adolescent, and young adult patients with VHL-associated hemangioblastomas.

Novel anticancer drug discovery strategies targeting hypoxia-inducible factors

INTRODUCTION

Hypoxia is a key feature of solid tumors, associated with aggressive behaviors such as radiation and chemotherapy resistance, increased metastasis, and poor prognosis. Hypoxia-inducible factors (HIFs) are essential transcription factors that help tumor cells adapt to hypoxic environments by promoting the expression of pro-oncogenic genes. Reducing HIF activity presents a promising strategy for advancing cancer treatment.

AREA COVERED

In this paper, the authors present an overview of recent studies on the development of HIF-1/2 inhibitors as potential anticancer drugs. The article offers a comprehensive analysis of the structural characteristics of these inhibitors and explores their relationship with anticancer activity, focusing on research conducted over the past decade, from 2015 to 2024.

EXPERT OPINION

Because they play a big role in medicinal chemistry and the discovery of anticancer drugs, HIF inhibitors have always gotten a lot of attention and have been used to make a lot of important molecules with different biological effects, especially in the field of cancer research. Several techniques and chemical scaffolds have successfully targeted HIF-1α. However, additional research is required to sustain HIF-1α inhibition while maintaining anticancer activity. The FDA approval of Belzutifan provided researchers with an opportunity to conduct broader HIF-2 studies.

The molecular code of kidney cancer: A path of discovery for gene mutation and precision therapy

Renal cell carcinoma (RCC) is a malignant tumor with highly heterogeneous and complex molecular mechanisms. Through systematic analysis of TCGA, COSMIC and other databases, 24 mutated genes closely related to RCC were screened, including VHL, PBRM1, BAP1 and SETD2, which play key roles in signaling pathway transduction, chromatin remodeling and DNA repair. The PI3K/AKT/mTOR signaling pathway is particularly important in the pathogenesis of RCC. Mutations in genes such as PIK3CA, MTOR and PTEN are closely associated with metabolic abnormalities and tumor cell proliferation. Clinically, mTOR inhibitors and VEGF-targeted drugs have shown significant efficacy in personalized therapy. Abnormal regulation of metabolic reprogramming, especially glycolysis and glutamine metabolic pathways, provides tumor cells with continuous energy supply and survival advantages, and GLS1 inhibitors have shown promising results in preclinical studies. This paper also explores the potential of immune checkpoint inhibitors in combination with other targeted drugs, as well as the promising application of nanotechnology in drug delivery and targeted therapy. In addition, unique molecular mechanisms are revealed and individualized therapeutic strategies are explored for specific subtypes such as TFE3, TFEB rearrangement type and SDHB mutant type. The review summarizes the common gene mutations in RCC and their molecular mechanisms, emphasizes their important roles in tumor diagnosis, treatment and prognosis, and looks forward to the application prospects of multi-pathway targeted therapy, metabolic targeted therapy, immunotherapy and nanotechnology in RCC treatment, providing theoretical support and clinical guidance for individualized treatment and new drug development.

Targeting HIF-2α: the role of belzutifan in clear cell renal carcinoma management

INTRODUCTION

Belzutifan is a first-in-class hypoxia-inducible factor-2 alpha (HIF-2α) inhibitor. It targets the von Hippel-Lindau protein (pVHL)-HIF-vascular endothelial growth factor (VEGF) pathway, which is crucial in cellular responses to hypoxia. By inhibiting HIF-2α, belzutifan disrupts the transcription of genes involved in tumor growth and angiogenesis.

AREAS COVERED

In this review, we describe the pVHL-HIF-VEGF pathway and how it led to the development of HIF inhibitors, including belzutifan. A search was conducted for trials involving Belzutifan, including phase I-III trials. We describe the relevant toxicity, with emphasis on hypoxia and anemia.

EXPERT OPINION

Belzutifan is a relatively safe drug, with manageable adverse events, including anemia and hypoxia as on-target toxicity. Ongoing trials are studying its benefit in overall survival for RCC in first-line treatment and its potential in other malignancies. The LITESPARK-005 trial reported the benefit of belzutifan in progression-free survival (PFS) compared to everolimus in later lines of treatment, with improvement in quality-of-life outcomes. Given its different mechanism of action to currently available treatments, belzutifan is expected to play a prominent role in the treatment of clear cell renal carcinoma and other cancers.

FDA Approval Summary: Belzutifan for Patients with Advanced Renal Cell Carcinoma

On December 14, 2023, the U.S. FDA approved belzutifan (Welireg, Merck & Co., Inc.) for patients with advanced renal cell carcinoma (RCC) following treatment with a PD-1/PD-L1 inhibitor and a VEGF tyrosine kinase inhibitor. The FDA granted traditional approval based on LITESPARK-005 (NCT04195750), an open-label, randomized, head-to-head trial of 746 patients with advanced RCC that progressed following treatment with both a PD-1/PD-L1 inhibitor and a VEGF tyrosine kinase inhibitor. Patients were randomized (1:1) to receive belzutifan or everolimus. The primary endpoints were progression-free survival (PFS) assessed by blinded independent central review and overall survival. A statistically significant improvement in PFS was demonstrated for belzutifan compared with everolimus [HR = 0.75; 95% confidence interval (CI), 0.63-0.90; one-sided P value = 0.0008]. Kaplan-Meier curves reflected nonproportional hazards with similar median PFS estimates of 5.6 months (95% CI, 3.9-7.0) in the belzutifan arm and 5.6 months (95% CI, 4.8-5.8) in the everolimus arm. Although not reaching full maturity, the overall survival results seemed to show a favorable trend in the belzutifan arm compared with the everolimus arm (HR, 0.88; 95% CI, 0.73-1.07). The confirmed objective response rate by blinded independent central review was 22% and 3.6% in the belzutifan and everolimus arms, respectively. Observed toxicities differed between treatment arms, but drug discontinuations and interruptions due to treatment-emergent adverse events were lower in the belzutifan arm compared with the everolimus arm, and a descriptive analysis of patient-reported symptom and functional outcomes was suggestive of favorable tolerability for belzutifan compared with everolimus.

The Evolving Molecular Landscape and Actionable Alterations in Urologic Cancers

The genetic landscape of urologic cancers has evolved with the identification of actionable mutations that impact diagnosis, prognosis, and therapeutic strategies. This narrative review consolidates existing literature on genetic mutations across key urologic cancers, including bladder, renal, prostate, upper tract urothelial, testicular, and penile. The review highlights mutations in DNA damage repair genes, such as BRCA1/2 and PTEN, as well as pathway alterations like FGFR and PD-L1 overexpression. These mutations influence tumor behavior and therapeutic outcomes, emphasizing the need for precision oncology approaches. Molecular profiling, through tools like next-generation sequencing, has revolutionized patient care by enabling targeted treatment strategies, especially in cancers with distinct molecular subtypes such as luminal or basal bladder cancer and clear cell renal carcinoma. Emerging therapies, including FGFR inhibitors and immune checkpoint blockade, offer new treatment avenues, although resistance mechanisms remain a challenge. We also emphasize the importance of biomarker identification for personalized management, especially in metastatic settings where treatment intensification is often required. Future research is needed to further elucidate our understanding of the genetics affecting urologic cancers, which will help develop novel, individualized therapies to enhance oncologic outcomes.

Von Hippel-Lindau protein signalling in clear cell renal cell carcinoma

The distinct pathological and molecular features of kidney cancer in adaptation to oxygen homeostasis render this malignancy an attractive model for investigating hypoxia signalling and potentially developing potent targeted therapies. Hypoxia signalling has a pivotal role in kidney cancer, particularly within the most prevalent subtype, known as renal cell carcinoma (RCC). Hypoxia promotes various crucial pathological processes, such as hypoxia-inducible factor (HIF) activation, angiogenesis, proliferation, metabolic reprogramming and drug resistance, all of which contribute to kidney cancer development, growth or metastasis formation. A substantial portion of kidney cancers, in particular clear cell RCC (ccRCC), are characterized by a loss of function of Von Hippel-Lindau tumour suppressor (VHL), leading to the accumulation of HIF proteins, especially HIF2α, a crucial driver of ccRCC. Thus, therapeutic strategies targeting pVHL-HIF signalling have been explored in ccRCC, culminating in the successful development of HIF2α-specific antagonists such as belzutifan (PT2977), an FDA-approved drug to treat VHL-associated diseases including advanced-stage ccRCC. An increased understanding of hypoxia signalling in kidney cancer came from the discovery of novel VHL protein (pVHL) targets, and mechanisms of synthetic lethality with VHL mutations. These breakthroughs can pave the way for the development of innovative and potent combination therapies in kidney cancer.

Hypoxia-inducible transcription factors: architects of tumorigenesis and targets for anticancer drug discovery

Hypoxia-inducible factors (HIFs) play a pivotal role as master regulators of tumor survival and growth, controlling a wide array of cellular processes in response to hypoxic stress. Clinical data correlates upregulated HIF-1 and HIF-2 levels with an aggressive tumor phenotype and poor patient outcome. Despite extensive validation as a target in cancer, pharmaceutical targeting of HIFs, particularly the interaction between α and βsubunits that forms the active transcription factor, has proved challenging. Nonetheless, many indirect inhibitors of HIFs have been identified, targeting diverse parts of this pathway. Significant strides have also been made in the development of direct inhibitors of HIF-2, exemplified by the FDA approval of Belzutifan for the treatment of metastatic clear cell renal carcinoma. While efforts to target HIF-1 using various therapeutic modalities have shown promise, no clinical candidates have yet emerged. This review aims to provide insights into the intricate and extensive role played by HIFs in cancer, and the ongoing efforts to develop therapeutic agents against this target.

Targeting circadian transcriptional programs through a cis-regulatory mechanism in triple negative breast cancer

Circadian clock genes are emerging targets in many types of cancer, but their mechanistic contributions to tumor progression are still largely unknown. This makes it challenging to stratify patient populations and develop corresponding treatments. In this work, we show that in breast cancer, the disrupted expression of circadian genes has the potential to serve as biomarkers. We also show that the master circadian transcription factors (TFs) BMAL1 and CLOCK are required for the proliferation of metastatic mesenchymal stem-like (mMSL) triple-negative breast cancer (TNBC) cells. Using currently available small molecule modulators, we found that a stabilizer of cryptochrome 2 (CRY2), the direct repressor of BMAL1 and CLOCK transcriptional activity, synergizes with inhibitors of proteasome, which is required for BMAL1 and CLOCK function, to repress a transcriptional program comprising circadian cycling genes in mMSL TNBC cells. Omics analyses on drug-treated cells implied that this repression of transcription is mediated by the transcription factor binding sites (TFBSs) features in the cis-regulatory elements (CRE) of clock-controlled genes. Through a massive parallel reporter assay, we defined a set of CRE features that are potentially repressed by the specific drug combination. The identification of cis -element enrichment might serve as a new concept of defining and targeting tumor types through the modulation of cis -regulatory programs, and ultimately provide a new paradigm of therapy design for cancer types with unclear drivers like TNBC.

Spinal cord hemangioblastomas in von Hippel-Lindau disease

Background

von Hippel-Lindau disease (VHL) is an autosomal dominant familial neoplasia syndrome. The most common manifestation of VHL is central nervous system hemangioblastomas. VHL patients will often develop multiple hemangioblastomas along their craniospinal axis over their lifetime. Spinal cord hemangioblastomas account for nearly half of all nervous system hemangioblastomas in VHL.

Methods

The authors conducted a literature review and summation of available articles on spinal cord hemangioblastomas associated with VHL.

Results

The embryological origins, epidemiology, natural history, surgical outcomes, nonsurgical treatments, and future directions in spinal cord hemangioblastomas are discussed.

Conclusions

Hemangioblastomas in VHL are optimally managed with a multidisciplinary approach that includes surgical resection of symptomatic lesions. Novel treatments are gaining traction, but must be studied further for efficacy and safety.

Innovative solutions? Belzutifan therapy for hemangioblastomas in Von Hippel-Lindau disease: A systematic review and single-arm meta-analysis

BACKGROUND

Von Hippel-Lindau (VHL) disease is a rare autosomal dominant disorder that predisposes patients to develop multiple cysts and tumors, such as hemangioblastomas (HBs) and clear cell renal cell carcinoma (ccRCC), due to mutations in the VHL tumor suppressor gene. While treatment of HBs varies based on their characteristics and has improved patient survival, it still involves high morbidity and mortality, leading to ongoing debates and studies to refine therapy strategies. Recent developments include the emergence of Belzutifan, a novel inhibitor targeting hypoxia-inducible factor 2α (HIF-2α), which has shown promising results in ongoing trials, particularly for patients not immediately requiring surgery.

METHODS

This systematic review and meta-analysis aimed to comprehensively evaluate the efficacy and safety of Belzutifan for treating HBs associated with VHL disease. Search was conducted across Medline, Embase, Cochrane, and Web of Science databases. Statistical Analysis was performed, with proportions and 95 % confidence intervals. Statistical analyses were carried out using R Studio.

RESULTS

Ten studies were selected, comprising 553 patients. The population mean age was 40 (24-65), and 50 % of the population was formed by males. In terms of proportion, 6 analyses were performed: Disease Stability of 31 % [95 %CI:14 %-47 %; I2 = 2 %]; Disease Progression of 2 %[95 %CI:0 %-9 %; I2 = 0 %]; Partial Response of 75 % [95 %CI:54 %-96 %; I2 = 58 %]. Complete response of 1 % [95 %CI:0 %-7 %; I2 = 0 %];and Side effects, anemia 81 % rate [95 % CI:54 %-100 %; I2 = 94 %], and fatigue rate of 79 % [95 % CI:54 %-100 %;I2 = 94 %].

CONCLUSION

Results indicate that Belzutifan effectively stabilizes disease, reduces tumor progression, and achieves significant therapeutic responses, although side effects like anemia and fatigue were noted.

Endolymphatic Sac Tumors Associated With von Hippel-Lindau: A Case Report Highlighting Opportunity for Novel Orphan Drug Therapy

OBJECTIVE

To discuss the potential benefit of belzutifan therapy in a patient with von Hippel-Lindau (VHL) disease-associated endolymphatic sac tumor (ELST).

PATIENTS

Case report.

INTERVENTIONS

Clinical details of a patient with residual ELST after hearing preservation surgery who initiated belzutifan therapy postoperatively for concurrent renal cell carcinoma, as well as literature review of belzutifan and ELST.

MAIN OUTCOME MEASURES

The patient remained without radiologic evidence of growth of her residual tumor at 17 months post-initiation of belzutifan. It is unknown whether this represents therapeutic drug effect, nonviability of residual tumor, or slow tumor growth not captured radiographically within the duration of follow-up.

CONCLUSIONS

Belzutifan could have direct therapeutic benefit in patients with VHL-associated ELST.

Gastroenteropancreatic neuroendocrine neoplasms: epidemiology, genetics, and treatment

The incidence of gastroenteropancreatic neuroendocrine neoplasms (GEP NEN) is increasing at a rapid pace and is becoming an increasingly important consideration in clinical care. Epidemiological data from multiple countries indicate that the incidence of gastroenteropancreatic neuroendocrine neoplasms (GEP NEN) exhibits regional, site-specific, and gender-based variations. While the genetics and pathogenesis of some GEP NEN, particularly pancreatic NENs, have been investigated, there are still many mechanisms that require further investigation. The management of GEP NEN is diverse, but surgery remains the primary option for most cases. Peptide receptor radionuclide therapy (PRRT) is an effective treatment, and several clinical trials are exploring the potential of immunotherapy and targeted therapy, as well as combination therapy.

Phenotypic and Genotypic Features of a Chinese Cohort with Retinal Hemangioblastoma

Purpose: To delineate the genotype and phenotype of RH in a Chinese cohort. Methods: A group of 51 Chinese probands with RH across 76 eyes was assembled and underwent complete retinal imaging examinations. Sanger sequencing and universal primer quantitative fluorescent multiplex-polymerase chain reaction (UPQFM-PCR) were employed for mutation detection in the coding region of the Von Hippel-Lindal (VHL) gene. For frequency calculation, our series was combined with three large cohorts of East Asian descent through a literature review. Results: The Von Hippel-Lindal (VHL) syndrome was excluded in fifteen patients (median age: 32.00 years) with unilateral solitary RH. Thirty-six patients of younger ages (median: 22.00 years, p = 0.008, Mann-Whitney test) conformed to the diagnostic criteria of the VHL syndrome, and thirty-four patients were genetically confirmed. There were four novel variants identified in the VHL gene. Codons 167, 161 and 86 exhibited a mutation occurrence of more than 5% after pooling with literature data, and the large genomic deletion demonstrated a frequency of 17.65%. The RHs were classified as "extrapapillary", "juxtapapillary" and "mixed" types in 53, 7 and 5 eyes, respectively. Almost all extrapapillary RH lesions were found in the peripheral retina. Hemangioblastomas in the central nervous system (CNS) were observed in 25 out of 31 kindreds (80.65%) with full systemic evaluation data. Conclusions: VHL-associated RH might exhibit earlier onset than non-VHL RH. Large genomic deletions were observed at a notably high frequency in the Chinese series with VHL-associated RH, which might be associated with East Asian ethnicity background. RH could potentially serve as an early indicator of CNS hemangioblastoma.

Targeting HIF-2α and anemia: A therapeutic breakthrough for clear-cell renal cell carcinoma

Renal cell carcinoma (RCC) is a heterogenous disease which the incidence is increasing worldwide. The identification and understanding of the role of the Von Hipple Lindau (VHP) in regulating the hypoxia-inducible factor signaling pathway has revolutionized the treatment of this disease. Belzutifan is an oral hypoxia-inducible factor (HIF)-2α inhibitor, which has demonstrated efficacy in treating von Hippel-Lindau (VHL) disease and for the treatment of adults with RCC who experienced disease progression after PD-1/PD-L1- and VEGFR-targeted therapies. One of the most common adverse effect of this drug is anemia; however, it is treatment is not well known. This review summarizes role of the VHL-HIF pathway in ccRCC aroused the interest of targeting HIF activity, the history of belzutifan development and their relationship to anemia as well as propose a management algorithm.

Belzutifan in Individuals with von Hippel-Lindau Retinal Hemangioblastomas: Institutional Experience and Review of the Literature

Introduction

The systemic HIF-2 alpha inhibitor, belzutifan, has been approved for use in patients with von Hippel-Lindau disease (VHL)-associated renal cell carcinoma, central nervous system (CNS) hemangioblastomas, and pancreatic neuroendocrine tumors. This drug has also shown promise in controlling VHL retinal hemangioblastomas (RHs), but little work has been published on the use of the drug in this setting.

Methods

We conducted a retrospective review of patients with VHL-associated RHs followed by the retina service at our institution who were treated with systemic belzutifan. Patient age, gender, genotype, presence of systemic tumors, indication for the drug, initial dose, adjusted dose, side effects, and tumor response were recorded. We also conducted a literature search for all manuscripts describing the effect of belzutifan on VHL-associated ocular tumors.

Results

We identified 12 eyes of 7 patients with VHL-associated ocular tumors who were treated with belzutifan at our institution. Of these, 5 eyes of 3 patients had progressing ocular tumors when belzutifan was started. Of the 7 total patients, 2 were treated for renal cell carcinoma, 2 for CNS hemangioblastomas, 2 for RHs, and one for pancreatic neuroendocrine tumors. Initial dose was 120 mg PO daily in 6 patients and 80 mg PO daily in 1 patient. The dose was reduced in all but 1 patient due to side effects. The ocular tumors were controlled in all patients with an average follow-up of 13 months (range 4-24 months). Literature review identified 7 manuscripts that described belzutifan-mediated control of ocular tumors in patients with VHL-associated RHs in 21 patients.

Conclusion

The drug belzutifan shows great promise for controlling RHs and preventing vision loss in patients with VHL. Further work needs to address the optimal dose, role of the drug as a neoadjuvant therapy, and long-term efficacy and tolerability of the drug in a larger cohort of patients with ocular tumors.

Pharmacologic HIF stabilization activates costimulatory receptor expression to increase antitumor efficacy of adoptive T cell therapy

Adoptive cell transfer (ACT) is a therapeutic strategy to augment antitumor immunity. Here, we report that ex vivo treatment of mouse CD8+ T cells with dimethyloxalylglycine (DMOG), a stabilizer of hypoxia-inducible factors (HIFs), induced HIF binding to the genes encoding the costimulatory receptors CD81, GITR, OX40, and 4-1BB, leading to increased expression. DMOG treatment increased T cell killing of melanoma cells, which was further augmented by agonist antibodies targeting each costimulatory receptor. In tumor-bearing mice, ACT using T cells treated ex vivo with DMOG and agonist antibodies resulted in decreased tumor growth compared to ACT using control T cells and increased intratumoral markers of CD8+ T cells (CD7, CD8A, and CD8B1), natural killer cells (NCR1 and KLRK1), and cytolytic activity (perforin-1 and tumor necrosis factor-α). Costimulatory receptor gene expression was also induced when CD8+ T cells were treated with three highly selective HIF stabilizers that are currently in clinical use.

The tipping point: Key oncologic imaging findings resulting in critical changes in the management of malignant genitourinary and gynecological tumors

OBJECTIVE

The purpose of this article is to review the staging systems for common malignant genitourinary and gynecological tumors, including renal cell carcinoma, urinary bladder carcinoma, as well as cervical, endometrial, and ovarian carcinoma, and to highlight the key imaging findings ("tipping points") that may alter patient management algorithms based on radiological staging.

CONCLUSION

There are identifiable imaging features for the common genitourinary and gynecological malignancies, including the size of the primary tumor, tumor extension, invasion of adjacent structures, lymph node involvement, and distant metastasis, which provide important prognostic information and determine patient management. Radiologists must be aware of these imaging findings ("tipping points") when interpreting staging examinations.

Management of metastatic pheochromocytomas and paragangliomas: when and what

Recently, the treatment landscape for metastatic pheochromocytomas and paragangliomas (MPPGL) has seen both progress and setbacks. We provide an up-to-date review of the multimodality management of MPPGL and discuss novel opportunities and current challenges in the treatment landscape. Given the unique clinical presentation of MPPGL, we discuss the management of hormone-related clinical sequelae and traditional modalities of therapy. Advances in the understanding of the molecular biology of these diverse tumors have enabled novel strategies such as augmenting DNA damage by targeted delivery of radionuclides such as 131I and 177Lu, abrogating tumor angiogenesis, hypoxia resistance, and DNA damage repair. Despite progress, we address the significant challenges still faced by patients and researchers engaged in efforts to improve outcomes in these rare cancers.

The marine-derived HIF-1α inhibitor, Yardenone 2, reduces prostate cancer cell proliferation by targeting HIF-1 target genes

BACKGROUND

Prostate cancer (PCa) ranks as the second most prevalent cancer in men, with advanced stages posing significant treatment challenges. Given its solid tumor nature, PCa is highly susceptible to hypoxia, a condition associated with resistance to radiation and chemotherapy, metastasis, and unfavorable patient outcomes. Hypoxia-inducible factors (HIFs) play a pivotal role in cancer cell adaptation to hypoxic environments, contributing to treatment resistance. Consequently, inhibitors targeting HIFs hold promise for cancer therapy.

METHODS

In this study, we aimed to characterize novel HIF-1α inhibitors including Sodwanones A (1), B (2), C (3), G (4) and Yardenone 2 (5) isolated from marine sponges belonging to the Axinella genus. Our investigation evaluated the impact of these compounds on various aspects of HIF-1α regulation, including stabilization, nuclear localization, expression of HIF-1 target genes (while sparing HIF-2 target genes), cellular metabolism, as well as cell proliferation and viability in prostate cells under hypoxic conditions.

RESULTS

Our findings revealed that among the compounds tested, Yardenone 2 exhibited notable effects in hypoxia: it destabilized HIF-1α at the protein level, decreased its nuclear localization, selectively altered the expression of HIF-1 target genes, and restrained cell proliferation in aggressive PC3 prostate cancer cells as well as in an MSK-PCa3 patient-derived organoid line. Moreover, it affected the morphology of these organoid. Yardenone 2 was also compared to Docetaxel, a specific microtubule inhibitor and a drug used in the treatment of prostate cancer. The comparison between the two compounds revealed notable differences, such as a lack of specificity to hypoxic cells of Docetaxel.

CONCLUSION

These results mark the first demonstration that Yardenone 2 functions as a cytostatic-like inhibitor impacting microtubules, specifically targeting hypoxic cancer cells. This discovery suggests a promising avenue for novel therapeutic interventions in prostate cancer.

Germline Testing Identifies Pathogenic/Likely Pathogenic Variants in Patients with Pancreatic Neuroendocrine Tumors

Ten percent of pancreatic neuroendocrine tumors (pNET) are related to inherited syndromes (MEN1, MEN4, VHL, NF1, and TSC). Growing evidence suggests that clinically sporadic pNETs can also harbor germline pathogenic variants. In this study, we report the prevalence of pathologic/likely pathologic (P/LP) germline variants in a high-risk cohort and an unselected cohort. We collected clinical data of patients with pNETs seen at MD Anderson Cancer Center and Johns Hopkins Hospital. The high-risk cohort included (n = 132) patients seen at MD Anderson Cancer Center who underwent germline testing for high-risk criteria (early onset, personal or family history of cancer, and syndromic features) between 2013 and 2019. The unselected cohort included (n = 106) patients seen at Johns Hopkins Hospital who underwent germline testing following their diagnosis of pNETs between 2020 and 2022. In the high-risk cohort (n = 132), 33% (n = 44) had P/LP variants. The majority of the patients had P/LP variants in MEN1 56% (n = 25), followed by DNA repair pathways 18% (n = 8), and 7% (n = 3) in MSH2 (Lynch syndrome). Patients with P/LP were younger (45 vs. 50 years; P = 0.002). In the unselected cohort (n = 106), 21% (n = 22) had P/LP. The majority were noted in DNA repair pathways 40% (n = 9) and MEN1 36% (n = 8). Multifocal tumors correlated with the presence of P/LP (P = 0.0035). MEN1 germline P/LP variants correlated with younger age (40 vs. 56 years; P = 0.0012), presence of multifocal tumors (P < 0.0001), and World Health Organization grade 1 histology (P = 0.0078). P/LP variants are prevalent in patients with clinically sporadic pNET irrespective of high-risk features. The findings support upfront universal germline testing in all patients with pNET. Prevention Relevance: Here, we present germline data from the largest reported cohort of patients with pNET (n = 238), comprising both a high-risk cohort and an unselected cohort. In both cohorts, we identify a high number of P/LPs, including those in the DNA repair pathway. Our findings support universal germline testing in patients with pNET.

Current and Emerging Treatment Paradigms in Colorectal Cancer: Integrating Hallmarks of Cancer

The treatment of unresectable metastatic colorectal cancer has evolved over the last two decades, as knowledge of cancer biology has broadened and new targets have emerged. 'The Hallmarks of Cancer' illustrate the crucial capabilities acquired by cells to become malignant and represent the evolution of knowledge of tumor biology. This review integrates these novel targets and therapies into selected hallmarks: sustaining proliferative signaling, inducing vasculature, avoiding immune destruction, genome instability and mutation, reprogramming cellular metabolism, and resisting cell death. The different strategies and combinations under study are based on treatments with anti-EGFR, anti-VEGF, and anti-HER2 agents, KRAS G12C inhibitors, BRAF and MEK inhibitors, and immune checkpoint inhibitors. However, new approaches are emerging, including vaccines, WEE1 inhibitors, and PARP inhibitors, among others. The further deciphering of cancer biology will unravel new targets, develop novel therapies, and improve patients' outcomes.

Hypoxia-Inducible Factor-Dependent and Independent Mechanisms Underlying Chemoresistance of Hypoxic Cancer Cells

In hypoxic regions of malignant solid tumors, cancer cells acquire resistance to conventional therapies, such as chemotherapy and radiotherapy, causing poor prognosis in patients with cancer. It is widely recognized that some of the key genes behind this are hypoxia-inducible transcription factors, e.g., hypoxia-inducible factor 1 (HIF-1). Since HIF-1 activity is suppressed by two representative 2-oxoglutarate-dependent dioxygenases (2-OGDDs), PHDs (prolyl-4-hydroxylases), and FIH-1 (factor inhibiting hypoxia-inducible factor 1), the inactivation of 2-OGDD has been associated with cancer therapy resistance by the activation of HIF-1. Recent studies have also revealed the importance of hypoxia-responsive mechanisms independent of HIF-1 and its isoforms (collectively, HIFs). In this article, we collate the accumulated knowledge of HIF-1-dependent and independent mechanisms responsible for resistance of hypoxic cancer cells to anticancer drugs and briefly discuss the interplay between hypoxia responses, like EMT and UPR, and chemoresistance. In addition, we introduce a novel HIF-independent mechanism, which is epigenetically mediated by an acetylated histone reader protein, ATAD2, which we recently clarified.

Time course of tumorigenesis of a newly developed sporadic hemangioblastoma in an elderly patient: illustrative case

BACKGROUND

von Hippel-Lindau disease-associated hemangioblastomas (HBs) account for 20%-30% of all HB cases, with the appearance of new lesions often observed in the natural course of the disease. By comparison, the development of new lesions is rare in patients with sporadic HB.

OBSERVATIONS

A 65-year-old man underwent clipping for an unruptured aneurysm of the anterior communicating artery. Fourteen years later, follow-up magnetic resonance imaging (MRI) revealed a strongly enhanced mass in the right cerebellar hemisphere, diagnosed as a sporadic HB. A retrospective review of MRI studies obtained over the follow-up period revealed the gradual development of peritumoral edema and vascularization before mass formation.

LESSONS

Newly appearing high-intensity T2 lesions in the cerebellum may represent a preliminary stage of tumorigenesis. Careful monitoring of these patients would be indicated, which could provide options for early treatment to improve patient outcomes.

4-Fluoro-benzyl (Z)-2-(2-oxoindolin-3-yl-idene)hydrazine-1-carbodi-thio-ate

The title compound, C16H12FN3OS, a fluorinated di-thio-carbazate imine derivative, was synthesized by the one-pot, multi-component condensation reaction of hydrazine hydrate, carbon di-sulfide, 4-fluoro-benzyl chloride and isatin. The compound demonstrates near-planarity across much of the mol-ecule in the solid state and a Z configuration for the azomethine C=N bond. The Z form is further stabilized by the presence of an intra-molecular N-H⋯O hydrogen bond. In the extended structure, mol-ecules are linked into dimers by N-H⋯O hydrogen bonds and further connected into chains along either [20] or [100] by weak C-H⋯S and C-H⋯F hydrogen bonds, which further link into corrugated sheets and in combination form the overall three-dimensional network.

Pathogenesis of diabetic complications: Exploring hypoxic niche formation and HIF-1α activation

Hypoxia is a common feature of diabetic tissues, which highly correlates to the progression of diabetes. The formation of hypoxic context is induced by disrupted oxygen homeostasis that is predominantly driven by vascular remodeling in diabetes. While different types of vascular impairments have been reported, the specific features and underlying mechanisms are yet to be fully understood. Under hypoxic condition, cells upregulate hypoxia-inducible factor-1α (HIF-1α), an oxygen sensor that coordinates oxygen concentration and cell metabolism under hypoxic conditions. However, diabetic context exploits this machinery for pathogenic functions. Although HIF-1α protects cells from diabetic insult in multiple tissues, it also jeopardizes cell function in the retina. To gain a deeper understanding of hypoxia in diabetic complications, we focus on the formation of tissue hypoxia and the outcomes of HIF-1α dysregulation under diabetic context. Hopefully, this review can provide a better understanding on hypoxia biology in diabetes.

Impact of tissue-agnostic approvals on management of primary brain tumors

Novel tissue-agnostic therapeutics targeting driver mutations in tumor cells have been recently approved by FDA, driven by basket trials that have demonstrated their efficacy and safety across diverse tumor histology. However, the relative rarity of primary brain tumors (PBTs) has limited their representation in early trials of tissue-agnostic medications. Thus, consensus continues to evolve regarding utility of tissue-agnostic medications in routine practice for PBTs, a diverse group of neoplasms characterized by limited treatment options and unfavorable prognoses. We describe current and potential impact of tissue-agnostic approvals on management of PBTs. We discuss data from clinical trials for PBTs regarding tissue-agnostic targets, including BRAFV600E, neurotrophic tyrosine receptor kinase (NTRK) fusions, microsatellite instability-high (MSI-High), mismatch repair deficiency (dMMR), and high tumor mutational burden (TMB-H), in context of challenges in managing PBTs. Described are additional tissue-agnostic targets that hold promise for benefiting patients with PBTs, including RET fusion, fibroblast growth factor receptor (FGFR), ERBB2/HER2, and KRASG12C, and TP53Y220C.

Spinal Cord Neoplasms

OBJECTIVE

This article discusses the diagnostic approach to patients with suspected neoplasms of the spinal cord and reviews the most common primary and metastatic spinal neoplasms and their presentations.

LATEST DEVELOPMENTS

Neoplasms of the spinal cord are rare entities that can involve the spinal cord parenchyma, the dura and leptomeninges, or the extradural space. The most common intramedullary spinal cord neoplasms are primary spinal cord tumors, including ependymomas, pilocytic astrocytomas, and diffuse midline gliomas. The most common primary neoplasms of the spine are intradural extramedullary spinal meningiomas, whereas primary neoplasms of the leptomeninges are rare. Advances in molecular characterization of spinal cord tumors and recent clinical trials of these rare entities are expanding the repertoire of systemic therapy options for primary spinal cord neoplasms. Metastases to the spine most often affect the extradural space. Metastatic epidural spinal cord compression is a neurologic emergency that requires a rapid, multidisciplinary response to preserve neurologic function.

ESSENTIAL POINTS

Neurologists should understand the diagnostic approach to neoplasms of the spinal cord. Knowledge of the most common spinal cord neoplasms will allow for appropriate management and optimal patient care.

Stem Cell Theory of Cancer: Clinical Implications for Cellular Metabolism and Anti-Cancer Metabolomics

Although Otto Warburg may be right about the role of glycolysis versus OXPHOS in cancer metabolism, it remains unclear whether an altered metabolism is causative or correlative and is the main driver or a mere passenger in the pathogenesis of cancer. Currently, most of our successful treatments are designed to eliminate non-cancer stem cells (non-CSCs) such as differentiated cancer cells. When the treatments also happen to control CSCs or the stem-ness niche, it is often unintended, unexpected, or undetected for lack of a pertinent theory about the origin of cancer that clarifies whether cancer is a metabolic, genetic, or stem cell disease. Perhaps cellular context matters. After all, metabolic activity may be different in different cell types and their respective microenvironments-whether it is in a normal progenitor stem cell vs. progeny differentiated cell and whether it is in a malignant CSC vs. non-CSC. In this perspective, we re-examine different types of cellular metabolism, e.g., glycolytic vs. mitochondrial, of glucose, glutamine, arginine, and fatty acids in CSCs and non-CSCs. We revisit the Warburg effect, an obesity epidemic, the aspartame story, and a ketogenic diet. We propose that a pertinent scientific theory about the origin of cancer and of cancer metabolism influences the direction of cancer research as well as the design of drug versus therapy development in cancer care.

Novel Approaches with HIF-2α Targeted Therapies in Metastatic Renal Cell Carcinoma

Germline inactivation of the Von Hippel-Lindau (VHL) tumor suppressor is the defining hallmark in hereditary VHL disease and VHL-associated renal cell carcinoma (RCC). However, somatic VHL mutations are also observed in patients with sporadic RCC. Loss of function VHL mutations result in constitutive activation of hypoxia-inducible factor-2 alpha (HIF-2α), which leads to increased expression of HIF target genes that promote angiogenesis and tumor growth. As of 2023, belzutifan is currently the only approved HIF-2α inhibitor for both VHL-associated and sporadic metastatic RCC (mRCC). However, there is potential for resistance with HIF-2α inhibitors which warrants novel HIF-2α-targeting strategies. In this review, we discuss the potential resistance mechanisms with belzutifan and current clinical trials evaluating novel combinations of belzutifan with other targeted therapies and immune checkpoint inhibitors which may enhance the efficacy of HIF-2α targeting. Lastly, we also discuss newer generation HIF-2α inhibitors that are currently under early investigation and outline future directions and challenges with HIF-2α inhibitors for mRCC.

Hypoxic Signaling Pathways in Carotid Body Tumors

Carotid body tumors (CBTs) are rare tumors with a 1-2 incidence per 100,000 individuals. CBTs may initially present without apparent symptoms, and symptoms begin to arise since tumors grow bigger to compress surrounding tissue, such as recurrent laryngeal nerve and esophagus. Also, the etiology of CBTs remains unclear since it is more likely to occur in those who live in high-altitude areas or suffer from chronic hypoxic diseases such as COPD. SDH mutations and familial inheritance have been reported to be related to CBTs. SDH complexes play crucial roles in aerobic respiration, and SDH mutations in CBTs have been reported to be associated with hypoxia. Hypoxic signaling pathways, specifically hypoxic markers, have attracted more research attention in tumor exploration. However, the existing literature on these signaling and markers lacks a systematic review. Also, therapeutic approaches in CBTs based on hypoxic signaling are rarely used in clinics. In this review, we concluded the role of hypoxic signaling and markers and their potential implications in the initiation and progression of CBTs. Our findings underscore the involvement of the SDH family, the HIF family, VEGFs, and inflammatory cytokines (ICs) in tumorigenesis and treatment. Of particular interest is the role played by SDHx, which has recently been linked to oxygen sensing through mutations leading to hereditary CBTs. Among the SDH family, SDHB and SDHD exhibit remarkable characteristics associated with metastasis and multiple tumors. Besides SDH mutations in CBTs, the HIF family also plays crucial roles in CBTs via hypoxic signaling pathways. The HIF family regulates angiogenesis during mammalian development and tumor growth by gene expression in CBTs. HIF1α could induce the transcription of pyruvate dehydrogenase kinase 1 (PDK1) to inhibit pyruvate dehydrogenase kinase (PDH) by inhibiting the TCA cycle. Then, carotid body cells begin to hyperplasia and hypertrophy. At the same time, EPAS1 mutation, an activating mutation, could decrease the degradation of HIF2α and result in Pacak-Zhuang syndrome, which could result in paraganglioma. HIFs can also activate VEGF expression, and VEGFs act on Flk-1 to control the hyperplasia of type I cells and promote neovascularization. ICs also play a pivotal signaling role within the CB, as their expression is induced under hypoxic conditions to stimulate CB hyperplasia, ultimately leading to CBTs detecting hypoxic areas in tumors, and improving the hypoxic condition could enhance photon radiotherapy efficacy. Moreover, this review offers valuable insights for future research directions on understanding the relationship between hypoxic signaling pathways and CBTs.

HIF-1α: A potential therapeutic opportunity in renal fibrosis

Renal fibrosis is a common outcome of various renal injuries, leading to structural destruction and functional decline of the kidney, and is also a critical prognostic indicator and determinant in renal diseases therapy. Hypoxia is induced in different stress and injuries in kidney, and the hypoxia inducible factors (HIFs) are activated in the context of hypoxia in response and regulation the hypoxia in time. Under stress and hypoxia conditions, HIF-1α increases rapidly and regulates intracellular energy metabolism, cell proliferation, apoptosis, and inflammation. Through reprogramming cellular metabolism, HIF-1α can directly or indirectly induce abnormal accumulation of metabolites, changes in cellular epigenetic modifications, and activation of fibrotic signals. HIF-1α protein expression and activity are regulated by various posttranslational modifications. The drugs targeting HIF-1α can regulate the downstream cascade signals by inhibiting HIF-1α activity or promoting its degradation. As the renal fibrosis is affected by renal diseases, different diseases may trigger different mechanisms which will affect the therapy effect. Therefore, comprehensive analysis of the role and contribution of HIF-1α in occurrence and progression of renal fibrosis, and determination the appropriate intervention time of HIF-1α in the process of renal fibrosis are important ideas to explore effective treatment strategies. This study reviews the regulation of HIF-1α and its mediated complex cascade reactions in renal fibrosis, and lists some drugs targeting HIF-1α that used in preclinical studies, to provide new insight for the study of the renal fibrosis mechanism.

Total Synthesis of (+)-Discorhabdin V

The discorhabdin natural products are a large subset of pyrroloiminoquinone alkaloids with a myriad of biological activities. Despite garnering much synthetic attention, few members have thus far been completed, particularly those featuring a bridging carbon-nitrogen bond that is found in numerous discorhabdins, including discorhabdin V. Herein we report the first total synthesis and full stereochemical assignment of (+)-discorhabdin V. To access the pyrroloiminoquinone we developed a convergent N-alkylation/oxidative aminocyclization/bromination cascade that joins two key components, which are both made on multigram scale. An intramolecular Heck reaction then forms the quaternary carbon center in an intermediate containing the carbon-nitrogen bridge, and a reductive N,O-acetal cyclization sequence introduces the final piperidine ring. Furthermore, we have established the relative configuration of (+)-discorhabdin V through experimental NOESY data and DP4 NMR probability calculations. The absolute configuration of the natural product has also been determined by circular dichroism and the use of an amino acid derived chiral starting material. Our work represents one of only two reports of a total synthesis of a nitrogen-bridged discorhabdin and paves the way for future biological evaluation of such compounds.

Associations between HIFs and tumor immune checkpoints: mechanism and therapy

Hypoxia, which activates a variety of signaling pathways to enhance tumor cell growth and metabolism, is among the primary features of tumor cells. Hypoxia-inducible factors (HIFs) have a substantial impact on a variety of facets of tumor biology, such as epithelial-mesenchymal transition, metabolic reprogramming, angiogenesis, and improved radiation resistance. HIFs induce hypoxia-adaptive responses in tumor cells. Many academics have presented preclinical and clinical research targeting HIFs in tumor therapy, highlighting the potential applicability of targeted HIFs. In recent years, the discovery of numerous pharmacological drugs targeting the regulatory mechanisms of HIFs has garnered substantial attention. Additionally, HIF inhibitors have attained positive results when used in conjunction with traditional oncology radiation and/or chemotherapy, as well as with the very promising addition of tumor immunotherapy. Immune checkpoint inhibitors (CPIs), which are employed in a range of cancer treatments over the past decades, are essential in tumor immunotherapy. Nevertheless, the use of immunotherapy has been severely hampered by tumor resistance and treatment-related toxicity. According to research, HIF inhibitors paired with CPIs may be game changers for multiple malignancies, decreasing malignant cell plasticity and cancer therapy resistance, among other things, and opening up substantial new pathways for immunotherapy drug development. The structure, activation mechanisms, and pharmacological sites of action of the HIF family are briefly reviewed in this work. This review further explores the interactions between HIF inhibitors and other tumor immunotherapy components and covers the potential clinical use of HIF inhibitors in combination with CPIs.

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.

Evolution of the HIF targeted therapy in clear cell renal cell carcinoma

Clear cell renal cell carcinoma (ccRCC) is the most common type of kidney cancer, affecting hundreds of thousands of people worldwide and can affect people of any age. The pathogenesis of ccRCC is most commonly due to biallelic loss of the tumor suppressor gene VHL. VHL is the recognition subunit of an E3-ubiquitin-ligase-complex essential for degradation of the hypoxia-inducible factors (HIF) 1α and 2α. Dysfunctional degradation of HIF results in overaccumulation, which is particularly concerning with the HIF2α subunit. This leads to nuclear translocation, dimerization, and transactivation of numerous HIF-regulated genes responsible for cell survival and proliferation in ccRCC. FDA-approved therapies for RCC have primarily focused on targeting downstream effectors of HIF, then incorporated immunotherapeutics, and now, novel approaches are moving back to HIF with a focus on interfering with upstream targets. This review summarizes the role of HIF in the pathogenesis of ccRCC, novel HIF2α-focused therapeutic approaches, and opportunities for ccRCC treatment.

Congenital Cyanotic Heart Disease and the Association with Pheochromocytomas and Paragangliomas

PURPOSE OF REVIEW

Pheochromocytomas and paragangliomas (PPGLs) are rare neuroendocrine tumors that commonly produce excess catecholamines causing significant morbidity and mortality. Patients with cyanotic congenital heart disease (CCHD) develop PPGLs at a higher frequency than the general population. This review will summarize recent research in the association of PPGL and CCHD.

RECENT FINDINGS

Advances in molecular genetics have provided new insights into a variety of germline mutations and somatic mutations related to PPGLs. In the CCHD population, mutations can occur in the hypoxia signaling pathway with gain-of-function somatic mutations in EPAS1, which prevent degradation of hypoxia-inducible factor-2 alpha. These mutations are implicated in oncogenesis. PPGLs associated with CCHD develop as early as age 15 years and have predominantly noradrenergic secretion. Surgical removal is considered the first line of therapy, although belzutifan, a HIF-2α inhibitor, is currently being tested as a potential therapy. Early screening with plasma metanephrines may assist in identifying PPGLs in patients with CCHD.

Targeting intratumoral hypoxia to enhance anti-tumor immunity

Cancers express a large battery of genes by which they establish an immunosuppressive tumor microenvironment. Many of these genes are induced by intratumoral hypoxia through transcriptional activation mediated by hypoxia-inducible factors HIF-1 and HIF-2. This review summarizes several recent reports describing hypoxia-induced mechanisms of immune evasion in sarcoma and breast, colorectal, hepatocellular, prostate and uterine cancer. These studies point to several novel therapeutic approaches to improve anti-tumor immunity and increase responses to immunotherapy.

The outcome of central nervous system hemangioblastomas in Von Hippel-Lindau (VHL) disease treated with belzutifan: a single-institution retrospective experience

PURPOSE

Belzutifan is a Hypoxia Inducible Factor 2-alpha inhibitor approved in 2021 by the FDA for the treatment of renal cell carcinoma (RCC) in patients with Von-Hippel Landau (VHL) disease. These patients can also present with central nervous system (CNS) hemangioblastomas (HBs). We aim to study the effectiveness and adverse effects of belzutifan for CNS HBs, by reporting our preliminary institutional experience.

METHODS

We present a series of VHL patients with CNS HBs undergoing treatment with belzutifan for RCC. All the included patients met the RECIST inclusion criteria. The clinical and radiological outcome measures included: Objective response rate (ORR), time-to-response (TTR), adverse events (AE), and patient response. Patient response was classified as partial response (PR), complete response (CR), progressive disease (PD), or stable disease (SD).

RESULTS

Seven patients with 25 HBs were included in our study. A belzutifan dose of 120 mg/day PO was administered for a median of 13 months (range 10-17). Median follow up time was 15 months (range 10-24). An ORR of 71% was observed. The median TTR was 5 months (range: 1-10). None of the patients showed CR, while 5 patients (71.4%) showed PR and 2 (28.5%) showed SD. Among patients with SD the maximum tumor response was 20% [increase/decrease] of the lesion diameter. All the patients experienced decreased hemoglobin concentration, fatigue, and dizziness. None of the patients experienced severe anemia (grade 3-4 CTCAE).

CONCLUSION

Belzutifan appears to be an effective and safe treatment for CNS hemangioblastoma in VHL patients. Further clinical trials to assess the long-term effectiveness of the medication are required.

HIF1A-repressed PUS10 regulates NUDC/Cofilin1 dependent renal cell carcinoma migration by promoting the maturation of miR-194-5p

BACKGROUND

Renal cell carcinoma (RCC) is characterized by a high rate of distant metastasis, which leads to poor prognosis in patients with advanced RCC. PUS10 has been recognized as a member of the pseudouridine synthase family, and recently other functions beyond the synthesis of the RNA modification have been uncovered. However, little is known about its role in diseases such as cancer.

METHODS

RT-qPCR, western blot and immunohistochemistry were used to measure the expression of PUS10 in RCC tissues. Transwell assay, wound healing assay, and in vivo metastasis model were conducted to determine the function of PUS10 in RCC progression. MicroRNA sequencing and GEO database were used to screen for the downstream microRNAs of PUS10. RNA immunoprecipitation, dual luciferase reporter assay, immunostaining, and rescue experiments were employed to establish the PUS10/miR-194-5p/nuclear distribution protein C(NUDC)/Cofilin1 axis in RCC migration. Chromatin immunoprecipitation and dual luciferase reporter assay were used to verify its upstream transcriptional regulator.

RESULTS

The expression of PUS10 was significantly decreased in RCC tissues, and low expression predicted poor prognosis. In vitro and in vivo experiments showed that PUS10 suppressed RCC migration, which, however, was independent of its classical pseudouridine catalytic function. Mechanically, PUS10 promoted the maturation of miR-194-5p, which sequentially inhibited RCC migration via disrupting NUDC-dependent cytoskeleton. Furthermore, hypoxia and HIF-1 A were found involved in the downregulation of PUS10.

CONCLUSION

We unraveled PUS10 restrained RCC migration via the PUS10/miR-194-5p/NUDC/Cofilin1 pathway, which independent of its classical catalytic function. Furthermore, a linkage between the critical tumor microenvironment hallmark with malfunction of the forementioned metastasis inhibition mechanism was presented, as demonstrated by repressed expression of PUS10 due to hypoxia and HIF-1A.

Novel sights on therapeutic, prognostic, and diagnostics aspects of non-coding RNAs in glioblastoma multiforme

Glioblastoma Multiforme (GBM) is the primary brain tumor and accounts for 200,000 deaths each year worldwide. The standard therapy includes surgical resection followed by temozolomide (TMZ)-based chemotherapy and radiotherapy. The survival period of GBM patients is only 12-15 months. Therefore, novel treatment modalities for GBM treatment are urgently needed. Mounting evidence reveals that non-coding RNAs (ncRNAs) were involved in regulating gene expression, the pathophysiology of GBM, and enhancing therapeutic outcomes. The combinatory use of ncRNAs, chemotherapeutic drugs, and tumor suppressor gene expression induction might provide an innovative, alternative therapeutic approach for managing GBM. Studies have highlighted the role of Long non-coding RNAs (lncRNAs) and microRNAs (miRNAs) in prognosis and diagnosis. Dysregulation of ncRNAs is observed in virtually all tumor types, including GBMs. Studies have also indicated the blood-brain barrier (BBB) as a crucial factor that hinders chemotherapy. Although several nanoparticle-mediated drug deliveries were degrading effectively against GBM in vitro conditions. However, the potential to cross the BBB and optimum delivery of oligonucleotide RNA into GBM cells in the brain is currently under intense clinical trials. Despite several advances in molecular pathogenesis, GBM remains resistant to chemo and radiotherapy. Targeted therapies have less clinical benefit due to high genetic heterogeneity and activation of alternative pathways. Thus, identifying GBM-specific prognostic pathways, essential genes, and genomic aberrations provide several potential benefits as subtypes of GBM. Also, these approaches will provide insights into new strategies to overcome the heterogenous nature of GBM, which will eventually lead to successful therapeutic interventions toward precision medicine and precision oncology.

Belzutifan in adults with VHL-associated central nervous system hemangioblastoma: a single-center experience

PURPOSE

Belzutifan is a selective inhibitor of hypoxia-inducible factor 2 alpha (HIF-2a) that has emerged as a targeted therapy option for Von Hippel-Lindau (VHL) syndrome-associated tumors with recent FDA approval. There is limited real-world evidence regarding safety and efficacy in CNS hemangioblastoma. Our objective was to report on our clinical experience with belzutifan in adult patients with VHL-associated CNS hemangioblastoma.

METHODS

We retrospectively reviewed our institutional experience of belzutifan in adult patients (> 18 years of age at time of therapy) with VHL and craniospinal CNS hemangioblastomas not amenable to surgical resection. The period for study review was October 2021 to March 2023.

RESULTS

4 patients (all female) with a median age of 36 years at time of belzutifan initiation were included. Median duration of therapy at last follow-up was 11 months (6-17 months). All patients had radiographic response to therapy after a median of 3 months (2-5 months), with maximal response to therapy after a median of 8 months (3-17 months). Therapy was well tolerated, with the most common adverse effect being anemia. No patients had treatment pauses or dose adjustments due to belzutifan-related toxicity. No patients experienced hypoxia.

CONCLUSION

We showed that belzutifan is safe and well-tolerated with strong disease response for CNS hemangioblastoma in adults with VHL, supporting continued use of belzutifan in this patient population. Future studies should assess duration of treatment, effects of cessation after long-term use, and markers of therapeutic response.

HIF2α, Hepcidin and their crosstalk as tumour-promoting signalling

Not all aspects of the disruption of iron homeostasis in cancer have been fully elucidated. Iron accumulation in cancer cells is frequent for many solid tumours, and this is often accompanied by the contemporary rise of two key iron regulators, HIF2α and Hepcidin. This scenario is different from what happens under physiological conditions, where Hepcidin parallels systemic iron concentrations while HIF2α levels are inversely associated to Hepcidin. The present review highlights the increasing body of evidence for the pro-tumoral effect of HIF2α and Hepcidin, discusses the possible imbalance in HIF2α, Hepcidin and iron homeostasis during cancer, and explores therapeutic options relying on these pathways as anticancer strategies.

Targeting Cancer Metabolism to Improve Outcomes with Immune Checkpoint Inhibitors

Immune checkpoint inhibitors have revolutionized the treatment paradigm of several cancers. However, not all patients respond to treatment. Tumor cells reprogram metabolic pathways to facilitate growth and proliferation. This shift in metabolic pathways creates fierce competition with immune cells for nutrients in the tumor microenvironment and generates by-products harmful for immune cell differentiation and growth. In this review, we discuss these metabolic alterations and the current therapeutic strategies to mitigate these alterations to metabolic pathways that can be used in combination with checkpoint blockade to offer a new path forward in cancer management.

Inflammatory Networks in Renal Cell Carcinoma

Cancer-associated inflammation has been established as a hallmark feature of almost all solid cancers. Tumor-extrinsic and intrinsic signaling pathways regulate the process of cancer-associated inflammation. Tumor-extrinsic inflammation is triggered by many factors, including infection, obesity, autoimmune disorders, and exposure to toxic and radioactive substances. Intrinsic inflammation can be induced by genomic mutation, genome instability and epigenetic remodeling in cancer cells that promote immunosuppressive traits, inducing the recruitment and activation of inflammatory immune cells. In RCC, many cancer cell-intrinsic alterations are assembled, upregulating inflammatory pathways, which enhance chemokine release and neoantigen expression. Furthermore, immune cells activate the endothelium and induce metabolic shifts, thereby amplifying both the paracrine and autocrine inflammatory loops to promote RCC tumor growth and progression. Together with tumor-extrinsic inflammatory factors, tumor-intrinsic signaling pathways trigger a Janus-faced tumor microenvironment, thereby simultaneously promoting or inhibiting tumor growth. For therapeutic success, it is important to understand the pathomechanisms of cancer-associated inflammation, which promote cancer progression. In this review, we describe the molecular mechanisms of cancer-associated inflammation that influence cancer and immune cell functions, thereby increasing tumor malignancy and anti-cancer resistance. We also discuss the potential of anti-inflammatory treatments, which may provide clinical benefits in RCCs and possible avenues for therapy and future research.

Hypercapnic Tissue Gene Expression and Survival in Early-Stage Pancreatic Ductal Adenocarcinoma

BACKGROUND

Pancreatic ductal adenocarcinoma (PDAC) is an aggressive and lethal cancer. Hypercapnic tumor microenvironments were previously shown to promote cancer chemoresistance. In this study, we aimed to investigate the impact of tissue hypercapnia on PDAC prognosis.

STUDY DESIGN

PDAC cancer-cell lines were cultured in normocapnic (5% CO 2 ) and hypercapnic conditions (10% CO 2 ). RNA was extracted, and whole-exome transcriptome was sequenced. Differentially expressed genes were identified and used to construct a "hypercapnic gene set." PDAC transcriptomic patient data from the Tumor Cancer Genome Atlas was used to calculate single-sample gene set enrichment scores based on each patient's tissue expression of the hypercapnic gene set. Tissue hypercapnic scores (HSs) in PDAC patients (TMN stages Ia-IIb) were determined and correlated with clinicopathological parameters and overall survival.

RESULTS

A cohort of 135 resected stage I-II PDAC patients were assessed in this study. The average age was 65 ± 11.0 years, and the male:female ratio was 74:61. Median overall survival was 19.5 ± 1.4 months. High HSs were associated with increased tumor stage (p < 0.05) and higher lymph-node ratio (p < 0.05). In active smokers, high HS also correlated with smoking pack-years (p < 0.05). Cox regression analysis revealed high HS to be an independent prognostic factor for overall survival (hazard ratio [HR] 2.66, p = 0.004), along with lymph-node ratio (HR 4.2, p = 0.002) and age at diagnosis (HR 2.63, p = 0.01).

CONCLUSIONS

The pancreatic tumor microenvironment plays an integral role in tumor aggressiveness, and our previous in vitro data suggest that hypercapnia promotes an aggressive, more resistant phenotype. Herein, we show that in early-stage pancreatic cancer, hypercapnic tissue signatures corresponded with a worse overall survival.

Hypoxia-Inducible Factor-2α Signaling in the Skeletal System

Hypoxia-inducible factors (HIFs) are oxygen-dependent heterodimeric transcription factors that mediate molecular responses to reductions in cellular oxygen (hypoxia). HIF signaling involves stable HIF-β subunits and labile, oxygen-sensitive HIF-α subunits. Under hypoxic conditions, the HIF-α subunit is stabilized, complexes with nucleus-confined HIF-β subunit, and transcriptionally regulates hypoxia-adaptive genes. Transcriptional responses to hypoxia include altered energy metabolism, angiogenesis, erythropoiesis, and cell fate. Three isoforms of HIF-α-HIF-1α, HIF-2α, and HIF-3α-are found in diverse cell types. HIF-1α and HIF-2α serve as transcriptional activators, whereas HIF-3α restricts HIF-1α and HIF-2α. The structure and isoform-specific functions of HIF-1α in mediating molecular responses to hypoxia are well established across a wide range of cell and tissue types. The contributions of HIF-2α to hypoxic adaptation are often unconsidered if not outrightly attributed to HIF-1α. This review establishes what is currently known about the diverse roles of HIF-2α in mediating the hypoxic response in skeletal tissues, with specific focus on development and maintenance of skeletal fitness. © 2023 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.