HIF1α and HIF2α: sibling rivalry in hypoxic tumour growth and progression

Under (Genetic Selection) Pressure: Human Tumors and Human Populations in Hypoxia

Arenillas and colleagues report that pheochromocytomas and paragangliomas in the setting of chronic hypoxia due to cyanotic congenital heart disease harbor, at high frequency, somatic gain-of-function mutations in the EPAS1 gene, which encodes for one of the oxygen-labile subunits of the hypoxia-inducible factor complex. Interestingly, germline loss-of-function EPAS1 alleles are under natural selection in human populations subjected to a different chronic hypoxia condition, namely, high altitude. See related article by Arenillas et al., p. 1037.

The hypoxia signaling pathway in the development of acute myeloid leukemia

Acute myeloid leukemia (AML) is the most common acute leukemia in adults. Although advances in targeted agents have greatly improved the prognosis of patients with AML in recent years, those who fail to achieve remission or relapse after remission are still in urgent need of novel therapeutic strategies. The hypoxia signaling pathway is involved in various biological processes, and hypoxia-inducible factor alpha (HIF-α) is considered a potential therapeutic target in AML. The bone marrow microenvironment is known to be in a state of chronic hypoxia, which is important for hematopoietic stem cells to maintain quiescence, and provides leukemic stem cells with a refuge from immune defenses and chemotherapeutic agents. Therefore, this review aims to explore the role of the HIF-α signaling pathway in the development of AML.

The Potential Role of C4 MYH11+ Fibroblasts and the MDK-SDC2 Ligand-Receptor Pair in Lung Adenocarcinoma: Implications for Prognosis and Therapeutic Strategies

BACKGROUND

Lung adenocarcinoma (LUAD) posed a significant threat to global human health. This study employed single-cell RNA sequencing (scRNA-seq) to analyze transcriptomic data from nine LUAD patients at different stages of tumor infiltration, aiming to elucidate the tumor microenvironment and key biological processes of LUAD.

METHODS

In this study, we processed the scRNA-seq data using the Seurat package and sequentially applied principal component analysis followed by the Harmony package to effectively correct for batch effects, identifying 105,725 high-quality cells. Through cell clustering and gene expression profiling, we identified critical cell subpopulations and gene expression patterns in LUAD patients.

RESULTS

Our analysis revealed that the C4 MYH11+ Fibroblasts subtype was primarily involved in biological processes related to muscle function. Further investigations uncovered the MDK-SDC2 ligand-receptor pair as a critical regulator of tumor cell invasion, proliferation, and migration, driving LUAD progression. Additionally, we developed a gene-based prognostic model that effectively predicted patient survival, providing valuable clinical insights.

CONCLUSION

This study provided a comprehensive atlas of the LUAD tumor microenvironment, highlighted the role of the C4 MYH11+ Fibroblasts in tumor progression. It also proposed the MDK-SDC2 ligand-receptor pair as a novel mechanism, addressing a significant gap in this area of research. And presented a gene-based prognostic model as a novel perspective for research into immunotherapy and drug sensitivity in LUAD.

The deubiquitinase YOD1 suppresses tumor progression by stabilizing ZNF24 in clear cell renal carcinoma

Metastasis remains a significant challenge in the management of clear cell renal cell carcinoma (ccRCC), and a continued focus on its underlying mechanisms is crucial for improving patient outcomes and optimizing clinical therapies. The ovarian-tumor related protease (OTU) is involved in regulating critical cell signaling pathways, but the functions of most OTUs have yet to be explored. In this study, an unbiased RNAi screening revealed that ovarian tumor domain-containing 2 (YOD1) knockdown significantly promoted cell metastasis. YOD1 downregulation promoted ccRCC growth and metastasis both in vitro and in vivo. Notably, YOD1 knockdown stimulated the growth of organoids derived from ccRCC patients. Further investigation revealed that YOD1 directly interacted with and stabilized Zinc finger protein 24 (ZNF24) expression by deubiquitination in a manner dependent on its catalytic activity. YOD1 inhibition attenuated ZNF24 transcriptional repression of vascular endothelial growth factor A (VEGFA), thereby promoting VEGFA gene expression. Furthermore, ZNF24 was identified as a key mediator of YOD1 function. The expression of YOD1 and ZNF24 was significantly downregulated in tumor tissues, with a strong correlation between them. Importantly, reduced YOD1 and ZNF24 levels were strongly associated with poor clinical outcomes in ccRCC patients. Our results reveal the mechanism by which YOD1 regulates VEGFA transcription and suppresses tumorigenesis by deubiquitinating ZNF24, providing a therapeutic target in ccRCC.

Molecular landscape of clear cell renal cell carcinoma: targeting the Wnt/β-catenin signaling pathway

Clear cell renal cell carcinoma (ccRCC) is the most common subtype of renal cell carcinoma and is characterized by a complex molecular landscape driven by genetic and epigenetic alternations. Among the crucial signaling pathways implicated in ccRCC, the Wnt/β-catenin pathway plays a significant role in tumor progression and prognosis. This review delves into the molecular basis of ccRCC, highlighting the genetic and epigenetic modifications that contribute to its pathogenesis. We explore the significance of the Wnt/β-catenin pathway, focusing on its role in disease development, particularly the nuclear transport of β-catenin and its activation and downstream effects. Furthermore, we examine the role of antagonist genes in regulating this pathway within the context of ccRCC, providing insights into potential therapeutic targets. Dysregulation of this pathway, which is characterized by abnormal activation and nuclear translocation of β-catenin, plays a significant role in promoting tumor growth and metastasis. We explore the intricate molecular aspects of ccRCC, with a particular emphasis on this topic, underscoring the role of the pathway and emphasizing the importance and relevance of antagonist genes. Understanding the intricate interplay between these molecular mechanisms is crucial for developing innovative strategies to improve ccRCC treatment and patient outcomes.

Unraveling the role of hypoxia-inducible factors in cutaneous melanoma: from mechanisms to therapeutic opportunities

Hypoxia is a common feature of solid malignancies, including cutaneous melanoma (CM). Hypoxia-inducible factor (HIF)-1α and HIF-2α orchestrate cellular responses to hypoxia and coordinate a transcriptional program that promote several aggressive features in CM, such as angiogenesis, epithelial-mesenchymal transition, metastasis formation, metabolic rewiring, and immune escape. BRAFV600E, which is the most frequent mutation observed in CM patients, usually increases HIF-α signaling not only in hypoxia, but also in normoxic CM cells, enabling HIF-1α and HIF-2α to continuously activate downstream molecular pathways. In this review, we aim to provide a comprehensive overview of the intricate role and regulation of HIF-1α and HIF-2α in CM, with a brief focus on the complex interactions between HIF-α subunits and non-coding RNAs. We also discuss HIF-α-mediated cellular responses in normoxia along with the mechanisms that allow HIF-α subunits to maintain their stability under normal oxygen conditions. Finally, we resume available evidence on potential therapeutic approaches aimed at targeting HIF-1α and/or HIF-2α.

dFLASH; dual FLuorescent transcription factor activity sensor for histone integrated live-cell reporting and high-content screening

Live-cell transcription factor (TF) activity reporting is crucial for synthetic biology, drug discovery and functional genomics. Here we present dFLASH (dual FLuorescent transcription factor Activity Sensor for Histone-integrated live-cell reporting), a modular, genome-integrated TF sensor. dFLASH homogeneously and specifically detects endogenous Hypoxia Inducible Factor (HIF) and Progesterone Receptor (PGR) activities, as well as coactivator recruitment to synthetic TFs. The dFLASH system produces dual-color nuclear fluorescence, enabling normalized, dynamic, live-cell TF activity sensing with strong signal-to-noise ratios and robust screening performance (Z' = 0.61-0.74). We validate dFLASH for functional genomics and drug screening, demonstrating HIF regulation via CRISPRoff and application to whole-genome CRISPR KO screening. Additionally, we apply dFLASH for drug discovery, identifying HIF pathway modulators from a 1600-compound natural product library using high-content imaging. Together, this versatile platform provides a powerful tool for studying TF activity across diverse applications.

HIF regulates multiple translated endogenous retroviruses: Implications for cancer immunotherapy

Clear cell renal cell carcinoma (ccRCC), despite having a low mutational burden, is considered immunogenic because it occasionally undergoes spontaneous regressions and often responds to immunotherapies. The signature lesion in ccRCC is inactivation of the VHL tumor suppressor gene and consequent upregulation of the HIF transcription factor. An earlier case report described a ccRCC patient who was cured by an allogeneic stem cell transplant and later found to have donor-derived T cells that recognized a ccRCC-specific peptide encoded by a HIF-responsive endogenous retrovirus (ERV), ERVE-4. We report that ERVE-4 is one of many ERVs that are induced by HIF, translated into HLA-bound peptides in ccRCCs, and capable of generating antigen-specific T cell responses. Moreover, ERV expression can be induced in non-ccRCC tumors with clinical-grade HIF stabilizers. These findings have implications for leveraging ERVs for cancer immunotherapy.

Hypoxia-inducible factor 2α mediates nonesterified fatty acids and hypoxia-induced lipid accumulation in bovine hepatocytes

Ketosis is a metabolic disorder frequently occurring in the perinatal period, characterized by elevated circulating concentrations of nonesterified fatty acids (NEFA) due to negative energy balance, resulting in fatty liver in dairy cows. However, the mechanism of hepatic steatosis induced by high concentrations of NEFA in ketosis remains unclear. Hypoxia-inducible factor 2α (HIF-2α), which mediates adaptation to hypoxic stress, plays a critical role in regulating lipid metabolism. In this study, we investigate whether HIF-2α is involved in NEFA-driven hepatic lipid accumulation in dairy cows with ketosis. Liver and blood samples were collected from 10 healthy cows (blood BHB concentration <1.2 mM) and 10 ketotic cows (blood BHB concentration >3.0 mM with clinical symptoms) with similar lactation numbers (median = 3, range = 2-4) at 3 to 9 DIM (median = 6). In cows with ketosis, serum concentrations of NEFA and BHB were greater, but serum concentrations of glucose were lower. Moreover, hepatic triglyceride content increased significantly. In the liver of ketotic cows, which was accompanied by upregulated HIF-2α expression. To determine the potential association among hypoxia, HIF-2α, and the formation of hepatocellular steatosis in vitro, we isolated hepatocytes from healthy calves for the following experiments. First, hepatocytes were treated with 0, 0.6, 1.2, or 2.4 mM NEFA (52.7 mM stock NEFA solution was diluted in RPMI-1640 basic medium supplemented with 2% fatty acid-free BSA to achieve the specified concentrations) for 18 h, showing that HIF-2α expression and cellular hypoxia occurred in a dose-dependent manner. Next, hepatocytes were infected with HIF-2α (encoded by EPAS1) small interfering RNA (Si-HIF-2α) for 48 h and then treated with 1.2 mM NEFA for 18 h. Results indicated that silencing HIF-2α decreased NEFA-induced lipid accumulation in bovine hepatocytes. Subsequently, hepatocytes treated with or without NEFA were placed in an AnaeroPack System, mimicking a hypoxic condition, for 0, 12, 18, or 24 h. Results showed that hypoxia could induce and further exacerbate lipid accumulation in bovine hepatocytes. Meanwhile, normal or NEFA-treated hepatocytes were cocultured with or without PT2385, a specific HIF-2α inhibitor, showing that hypoxia promoted steatosis through HIF-2α. Activating transcription factor 4 (ATF4) is an endoplasmic reticulum (ER) stress and hypoxia-inducible transcription factor. Here, bovine hepatocytes were treated with NEFA or hypoxia following transfecting ATF4 small interfering RNA, which demonstrated that ATF4 knockdown alleviated the extent of lipid accumulation in bovine hepatocytes. In addition, we found that ATF4 expression was correlated with HIF-2α levels in both liver tissue and cultured hepatocyte models. Moreover, overexpression of ATF4 weakened the beneficial effects of HIF-2α inhibition. Overall, these data suggest that NEFA-induced hepatic hypoxia significantly contributes to the progression of hepatic steatosis which in turn, intensifies hypoxia and leads to a self-perpetuating cycle of reciprocal causation, further exacerbating hepatic lipid deposition. Additionally, accumulated HIF-2α plays a critical role in this complex-origin steatosis, potentially through ATF4.

Adaptation mechanisms in cancer: Lipid metabolism under hypoxia and nutrient deprivation as a target for novel therapeutic strategies (Review)

Tumor tissues generally exist in a relatively hypovascular state, and cancer cells must adapt to severe tissue conditions with a limited molecular oxygen and nutrient supply for their survival. Lipid metabolism serves a role in this adaptation. Lipids are supplied not only through the bloodstream but also through autonomous synthesis by cancer cells, and they function as sources of adenosine triphosphate and cell components. Although cancer‑associated lipid metabolism has been widely reviewed, how this metabolism responds to the tumor environment with poor molecular oxygen and nutrient supply remains to be fully discussed. The main aim of the present review was to summarize the findings on this issue and to provide insights into how cancer cells adapt to better cope with metabolic stresses within tumors. It may be suggested that diverse types of lipid metabolism have a role in enabling cancer cells to adapt to both hypoxia and nutrient‑poor conditions. Gaining a deeper understanding of these molecular mechanisms may reveal novel possibilities of exploration for cancer treatment.

CAR T cell-driven induction of iNOS in tumor-associated macrophages promotes CAR T cell resistance in B cell lymphoma

Chimeric antigen receptor (CAR) T cell therapies have revolutionized B cell malignancy treatment, but subsets of patients with large B cell lymphoma (LBCL) experience primary resistance or relapse after CAR T cell treatment. To uncover tumor microenvironment (TME)-induced resistance mechanisms, we examined patients' intratumoral immune infiltrates and observed that elevated levels of immunoregulatory macrophages in pre-infusion tumor biopsies are correlated with poor clinical responses. CAR T cell-produced interferon-gamma (IFN-γ) promotes the expression of inducible nitric oxide synthase (iNOS, NOS2) in immunoregulatory macrophages, impairing CAR T cell function. Mechanistically, iNOS-expressing macrophages upregulated the p53 pathway, mediating apoptosis and cell cycle arrest in CAR T cells, while downregulating the MYC pathway involved in ribosome biogenesis and protein synthesis. Furthermore, CAR T cell metabolism is compromised by depletion of glycolytic intermediates and rewiring of the TCA cycle. Pharmacological inhibition of iNOS enhances the CAR T cell treatment efficacy in B cell tumor-bearing mice. Notably, elevated levels of iNOS+CD14+ monocytes were observed in leukaphereses of patients with non-durable response to CAR T cell therapy. These findings suggest that mitigating iNOS in tumor-associated macrophages (TAMs) by blocking IFN-γ secretion from CAR T cells will improve outcomes for LBCL patients.

Nidogen-1 suppresses cell proliferation, migration, and glycolysis via integrin β1-mediated HIF-1α downregulation in triple-negative breast cancer

Nidogen-1 (NID1) is a secreted glycoprotein widely distributed in basement membranes. NID1 interacts with extracellular matrix proteins such as collagen and laminin and has been implicated in the progression of various cancers. However, study on the role of NID1 in breast cancer is scarce and inconsistent. In this work, we found that the expression of NID1 is significantly lower in breast cancer tissue than in normal tissue. In addition, NID1 expression correlated negatively with a poor prognosis for breast cancer patients. Based on those findings, we speculated that NID1 might act as a cancer suppressor in breast cancer. To investigate the role of NID1 in breast cancer, we constructed NID1-overexpressing cell lines. NID1 overexpression decreased breast cancer cell proliferation, migration, and in vivo tumor growth. Moreover, glucose metabolism, which is known to enhance cancer cell proliferation and migration, was also decreased by NID1 overexpression. Mechanistically, NID1 overexpression downregulated hypoxia-inducible factor-1α (HIF-1α) expression at the transcription level. Furthermore, we found that NID1 reduced integrin β1 stability and downregulated the transcription of HIF-1α through the FAK/Src/NF-κB p65 signaling axis, which is downstream of integrin β1. Together, the results of this study demonstrate the tumor suppressive role of NID1 in triple-negative breast cancer.

Immunohistochemical analysis of smooth muscle actin and CD31 in feline post-injection site fibrosarcomas: association with tumour grade, vascular density, and multinucleated giant cells

BACKGROUND

Multinucleated giant cells are commonly observed in various malignancies; however their clinical and biological significance remains largely unexplored and it has been hypothesised that the cells may play a role in vascular mimicry, tumour progression and tumour survival. This study aimed to investigate the expression of smooth muscle actin and CD31 in feline post-injection site fibrosarcomas, focusing on relationships between multinucleated giant cells presence, tumour grade, and vascular density to elucidate their potential role in tumour progression.

RESULTS

A total of 61 feline post-injection site fibrosarcomas, histologically graded into grades I, II, and III, were examined immunohistochemically. Smooth muscle actin immunoreactivity was detected in 57/61 (93.4%) cases. Multinucleated giant cells expressing CD31 were identified in 39/61 (63.9%) cases, predominantly in high-grade tumours, with a correlation observed between multinucleated giant cell presence, tumour grade, and mitotic index. Vascular density differed across tumour grades. A negative correlation between vascular density, tumour grade and necrosis score was identified. Additionally, a negative correlation was observed between multinucleated giant cells presence and vascular density.

CONCLUSIONS

The findings suggest a complex tumour microenvironment in which multinucleated giant cells and vascular mimicry may facilitate tumour survival under hypoxic conditions, potentially contributing to an aggressive tumour phenotype.

Small-molecule RNA therapeutics to target prostate cancer

Tuning protein expression by targeting RNA structure using small molecules is an unexplored avenue for cancer treatment. To understand whether this vulnerability could be therapeutically targeted in the most lethal form of prostate cancer, castration-resistant prostate cancer (CRPC), we use a clinical small molecule, zotatifin, that targets the RNA helicase and translation factor eukaryotic initiation factor 4A (eIF4A). Zotatifin represses tumorigenesis in patient-derived and xenograft models and prolonged survival in vivo alongside hormone therapy. Genome-wide transcriptome, translatome, and proteomic analysis reveals two important translational targets: androgen receptor (AR), a key oncogene in CRPC, and hypoxia-inducible factor 1A (HIF1A), an essential cancer modulator in hypoxia. We solve the structure of the 5' UTRs of these oncogenic mRNAs and strikingly observe complex structural remodeling of these select mRNAs by this small molecule. Remarkably, tumors treated with zotatifin become more sensitive to anti-androgen therapy and radiotherapy. Therefore, "translatome therapy" provides additional strategies to treat the deadliest cancers.

Dynamic investigation of hypoxia-induced L-lactylation

The recently identified histone modification lysine lactylation can be stimulated by L-lactate and glycolysis. Although the chemical group added upon lysine lactylation was originally proposed to be the L-enantiomer of lactate (KL-la), two isomeric modifications, lysine D-lactylation (KD-la) and N-ε-(carboxyethyl) lysine (Kce), also exist in cells, with their precursors being metabolites of glycolysis. The dynamic regulation and differences among these three modifications in response to hypoxia remain poorly understood. In this study, we demonstrate that intracellular KL-la, but not KD-la or Kce, is up-regulated in response to hypoxia. Depletion of glyoxalase enzymes, GLO1 and GLO2, had minimal impact on KD-la, Kce, or hypoxia-induced KL-la. Conversely, blocking glycolytic flux to L-lactate under hypoxic conditions by knocking out lactate dehydrogenase A/B completely abolished the induction of KL-la but increased KD-la and Kce. We further observed a correlation between the level of KL-la and hypoxia-inducible factor 1 alpha (HIF-1α) expression under hypoxic conditions and when small molecules were used to stabilize HIF-1α in the normoxia condition. Our result demonstrated that there is a strong correlation between HIF-1α and KL-la in lung cancer tissues and that patient samples with higher grade tend to have higher KL-la levels. Using a proteomics approach, we quantified 66 KL-la sites that were up-regulated by hypoxia and demonstrated that p300/CBP contributes to hypoxia-induced KL-la. Collectively, our study demonstrates that KL-la, rather than KD-la or Kce, is the prevailing lysine lactylation in response to hypoxia. Our results therefore demonstrate a link between KL-la and the hypoxia-induced adaptation of tumor cells.

Unraveling the Microenvironment and the Pathogenic Axis of HIF-1α-Visfatin-Fibrosis in Autoimmune Pancreatitis Using a Single-Cell Atlas

Autoimmune pancreatitis (AIP) is identified as a severe chronic immune-related disorder in pancreas, including two subtypes. In this study, pancreatic lesions in patients diagnosed as either type 1 AIP or type 2 AIP are examined, and these patients' peripheral blood at single-cell level. Furthermore, flow cytometry, immunofluorescence, and functional assays are performed to verify the identified cell subtypes. In type 1 AIP, there is a notable increase in the amount of B cells and plasma cells, and IgG4+ plasma cells are key pathogenic cells of AIP. The differentiation path of naïve-stage B cells into IgG4+ produced plasma cells is observed, and an increased amount of T helper cells and T follicular helper (Tfh) cells. This study also reveals that HIF-1α, an activated transcriptional factor, can directly bind to promoter site of NAMPT, promoting higher levels of visfatin production in HIF1A+ classical monocytes. Pancreatic stellate cells can be activated by extracellular visfatin and promote the development of fibrotic response in pancreatic lesions across both AIP subtypes. The current findings shed light on the exploration of dynamic alterations in peripheral blood cells and cell subgroups in pancreatic lesions of AIP, while elucidating a pathogenic cell subset and potential fibrosis mechanism of AIP.

Cancer stem cells: Masters of all traits

Cancer is a heterogeneous disease, which contributes to its rapid progression and therapeutic failure. Besides interpatient tumor heterogeneity, tumors within a single patient can present with a heterogeneous mix of genetically and phenotypically distinct subclones. These unique subclones can significantly impact the traits of cancer. With the plasticity that intratumoral heterogeneity provides, cancers can easily adapt to changes in their microenvironment and therapeutic exposure. Indeed, tumor cells dynamically shift between a more differentiated, rapidly proliferating state with limited tumorigenic potential and a cancer stem cell (CSC)-like state that resembles undifferentiated cellular precursors and is associated with high tumorigenicity. In this context, CSCs are functionally located at the apex of the tumor hierarchy, contributing to the initiation, maintenance, and progression of tumors, as they also represent the subpopulation of tumor cells most resistant to conventional anti-cancer therapies. Although the CSC model is well established, it is constantly evolving and being reshaped by advancing knowledge on the roles of CSCs in different cancer types. Here, we review the current evidence of how CSCs play a pivotal role in providing the many traits of aggressive tumors while simultaneously evading immunosurveillance and anti-cancer therapy in several cancer types. We discuss the key traits and characteristics of CSCs to provide updated insights into CSC biology and highlight its implications for therapeutic development and improved treatment of aggressive cancers.

MicroRNA profiling identifies VHL/HIF-2α dependent miR-2355-5p as a key modulator of clear cell Renal cell carcinoma tumor growth

Inactivation of the von Hippel-Lindau (VHL) tumor suppressor gene is one of the first truncal events in clear cell Renal Cell Carcinoma (ccRCC) tumorigenesis. The accumulation of Hypoxia Induced Factor (HIFα) resulting from VHL loss can promote ccRCC tumorigenesis by regulating microRNA (miRNA) expression. Here, we performed miRNA profiling and high-throughput analysis to identify a panel of VHL-dependent miRNAs in ccRCC. Validation of these miRNAs revealed the overexpression of miR-2355-5p in ccRCC cell models and primary tumors. Moreover, we showed a significant increase in circulating miR-2355-5p in plasma from patients with ccRCC. Mechanistically, miR-2355-5p overexpression was confirmed to be HIF-2α dependent. Targeting miR-2355-5p with the CRISPR/Cas9 system not only negatively disrupted the ability of ccRCC cells to stimulate angiogenesis but also decreased cell proliferation and drastically reduced tumor growth in mouse xenograft models. Finally, a miR-2355-5p pulldown assay identified five tumor suppressor genes, ACO1, BTG2, CMTM4, SLIT2, and WDFY2, as potential targets. All five genes were significantly downregulated in ccRCC tumors and mouse xenograft tumors. The results from this research demonstrate the oncogenic ability of miR-2355-5p and shed light on the possible mechanism by which this miRNA controls angiogenesis and tumor growth in VHL-deficient ccRCC.

Adaptation of Natural Killer Cells to Hypoxia: A Review of the Transcriptional, Translational, and Metabolic Processes

As important innate immune cells, natural killer (NK) cells play an essential role in resisting pathogen invasion and eliminating transformed cells. However, the hypoxic microenvironment caused by disease conditions is an important physicochemical factor that impairs NK cell function. With the increasing prominence of NK cells in immunotherapy, there has been a surge of interest in developing biological means through which NK cells may overcome the inhibition caused by hypoxia in disease conditions. Although the effects of hypoxic conditions in shaping the functions of NK cells have been increasingly recognized and investigated, reviews have been scantly. A comprehensive understanding of how NK cells adapt to hypoxia can provide valuable insights into how the functional capacity of NK cells may be restored. This review focuses on the functional alterations of NK cells in response to hypoxia. It delineates the mechanisms by which NK cells adapt to hypoxia at the transcriptional, metabolic, translational levels. Furthermore, given the complexity of the hypoxic microenvironment, we also elucidated the effects of key hypoxic metabolites on NK cells. Finally, this review discusses the current clinical therapies derived from targeting hypoxic NK cells. The study of NK cell adaptation to hypoxia has yielded new insights into immunotherapy. These insights may lead to development of novel strategies to improve the treatment of infectious diseases and cancer.

Multi-drug sequential release systems: Construction and application for synergistic tumor treatment

In tumor treatment, the sequence and timing of drug action have a large influence on therapeutic efficacy. Multi-drug sequential release systems (MDSRS) enable the sequential and/or on-demand release of multiple drugs following the single administration of a therapeutic agent. Several researchers have explored MDSRS, providing fresh strategies for synergistic cancer therapy. This review article first introduces the main characteristics of MDSRS. It then elaborates on the design principles of MDSRS. Subsequently, it summarizes the various structures of carriers used for constructing MDSRS, including core-shell structure, Layer-by-layer structure, Janus structure and hydrogel. Next, through specific examples, the article emphasizes the application of MDSRS in cancer treatment, focusing on their role in remodeling the tumor microenvironment (TME) and enhancing therapeutic effects through multiple mechanisms. Finally, the article discusses the current limitations and challenges of these systems and proposes potential future solutions. Overall, this review underscores the importance of the sequence and timing of drug therapy in cancer treatment, providing valuable theoretical and technical guidance for pharmaceutical research.

Clinical and Prognostic Value of VHL in Korean Patients with Rectal Cancer

Background and Objectives: Von Hippel-Lindau (VHL) disease is caused by mutations in the VHL gene and can develop various cancers. Hypoxia-inducible factors 1 and 2 alphas, regulated by the VHL gene, can increase the levels of vascular endothelial growth factor, thereby activating cancer progression. Here, we demonstrated clinical and prognostic values of VHL expression in rectal cancer (RC). Materials and Methods: Von Hippel-Lindau mRNA expression was examined in 60 patients with RC. Furthermore, we evaluated survival to determine the prognostic significance of VHL mRNA expression levels in RC using the Cancer Genome Atlas (TCGA) data. Results: Lower VHL expression was correlated with the recurrence (p = 0.058) and lymphatic invasion (p = 0.078), although it was not statistically significant. In TCGA data, VHL expression level was correlated with the M stage (p = 0.044); however, it had a possible association with lymphatic invasion (p = 0.068) and N stage (p = 0.104). Survival analysis showed that lower VHL gene expression predicted poorer survival in both patients with RC and TCGA data. Conclusions: This study identified a significant correlation between VHL gene expression and RC for the first time using patient tissues and TCGA data, suggesting that the VHL gene expression level could be a potential biomarker or candidate for the treatment of RC. Further studies are required to identify the molecular pathogenesis and clinical characteristics of VHL disease in RC.

Beyond immortality: Epstein-Barr virus and the intricate dance of programmed cell death in cancer development

This comprehensive review delves into the intricate role of programmed cell death in Epstein-Barr virus (EBV)-associated malignancies, focusing on the sophisticated interplay between viral mechanisms and the host's immune response. The central objective is to unravel how EBV exerts control over cell death pathways such as apoptosis, ferroptosis, and autophagy, thereby fostering its persistence and oncogenic potential. By dissecting these mechanisms, the review seeks to identify therapeutic strategies that could disrupt EBV's manipulation of these pathways, enhancing immune recognition and opening new avenues for targeted treatment. A deeper understanding of the molecular underpinnings of EBV's influence on cell death not only enriches the field of viral oncology but also pinpoints targets for drug development. Furthermore, the insights gleaned from this review could catalyze the design of vaccines aimed at preventing EBV infection or curtailing its oncogenic impact. Innovatively, the review synthesizes recent discoveries on the multifaceted roles of non-coding RNAs and cellular signaling pathways in modulating cell death within the context of EBV infection. By consolidating current knowledge and identifying areas where understanding is lacking, it lays the groundwork for future research that could lead to significant advancements in vaccine development and therapeutic interventions for EBV-related cancers. This review underscores the critical necessity for ongoing investigation into the complex interplay between EBV and host cell death mechanisms, with the ultimate goal of enhancing patient outcomes in EBV-associated diseases.

Nuclear speckles regulate functional programs in cancer

Nuclear speckles are dynamic nuclear bodies characterized by high concentrations of factors involved in RNA production. Although the contents of speckles suggest multifaceted roles in gene regulation, their biological functions are unclear. Here we investigate speckle variation in human cancer, finding two main signatures. One speckle signature was similar to healthy adjacent tissues, whereas the other was dissimilar, and considered an aberrant cancer speckle state. Aberrant speckles show altered positioning within the nucleus, higher levels of the TREX RNA export complex and correlate with poorer patient outcomes in clear cell renal cell carcinoma (ccRCC), a cancer typified by hyperactivation of the HIF-2α transcription factor. We demonstrate that HIF-2α promotes physical association of certain target genes with speckles depending on HIF-2α protein speckle-targeting motifs, defined in this study. We identify homologous speckle-targeting motifs within many transcription factors, suggesting that DNA-speckle targeting may be a general gene regulatory mechanism. Integrating functional, genomic and imaging studies, we show that HIF-2α gene regulatory programs are impacted by speckle state and by abrogation of HIF-2α-driven speckle targeting. These findings suggest that, in ccRCC, a key biological function of nuclear speckles is to modulate expression of select HIF-2α-regulated target genes that, in turn, influence patient outcomes. Beyond ccRCC, tumour speckle states broadly correlate with altered functional pathways and expression of speckle-associated gene neighbourhoods, exposing a general link between nuclear speckles and gene expression dysregulation in human 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.

Hypoxia enhances IL-8 signaling through inhibiting miR-128-3p expression in glioblastomas

Glioblastoma multiforme (GBM) is an aggressive type of brain tumor known for its hypoxic microenvironment. Understanding the dysregulated mechanisms in hypoxic GBM is crucial for its effective treatment. Through data mining of The Cancer Genome Atlas (TCGA) with hypoxia enrichment scores and in vitro experiments, miR-128-3p was negatively correlated with hypoxia signaling and the epithelial-mesenchymal transition (EMT). Additionally, lower miR-128-3p levels existed in hypoxic GBM, leading to desensitizing temozolomide (TMZ)'s efficacy, a first-line therapeutic drug for GBM. Overexpressing miR-128-3p enhanced both the in vitro and in vivo sensitivity of hypoxic gliomas to TMZ treatment. Mechanistically, HIF-1α suppressed miR-128-3p expression in hypoxic GBM. Through establishing miR-128-3p-mediated transcriptomic profiles and data mining, interleukin (IL)-8 was selected. IL-8 respectively showed positive and negative correlations with hypoxia and miR-128-3p, and was associated with poor TMZ therapeutic results in GBM. Elevated miR-128-3p, which targets both the 3'-untranslated region (UTR) and 5'UTR of IL-8, resulted in suppression of IL-8 expression. Moreover, IL-8 was validated to be involved in HIF-1α/miR-128-3p-regulated TMZ sensitivity and the EMT in hypoxic GBM cells. Collectively, the HIF-1α/miR-128-3p/IL-8 signaling pathway plays a critical role in promoting the progression of hypoxic GBM. Targeting this signaling pathway holds promise as a potential therapeutic strategy.

Hypoxia as a critical player in extracellular vesicles-mediated intercellular communication between tumor cells and their surrounding microenvironment

In the past years, increasing attention has been paid to the role of extracellular vesicles (EVs) as mediators of intercellular communication in cancer. These small size particles mediate the intercellular transfer of important bioactive molecules involved in malignant initiation and progression. Hypoxia, or low partial pressure of oxygen, is recognized as a remarkable feature of solid tumors and has been demonstrated to exert a profound impact on tumor prognosis and therapeutic efficacy. Indeed, the high-pitched growth rate and chaotic neovascular architecture that embodies solid tumors results in a profound reduction in oxygen pressure within the tumor microenvironment (TME). In response to oxygen-deprived conditions, tumor cells and their surrounding milieu develop homeostatic adaptation mechanisms that contribute to the establishment of a pro-tumoral phenotype. Latest evidence suggests that the hypoxic microenvironment that surrounds the tumor bulk may be a clincher for the observed elevated levels of circulating EVs in cancer patients. Thus, it is proposed that EVs may play a role in mediating intercellular communication in response to hypoxic conditions. This review focuses on the EVs-mediated crosstalk that is established between tumor cells and their surrounding immune, endothelial, and stromal cell populations, within the hypoxic TME.

Role of Hypoxia-Associated Long Noncoding RNAs in Cancer Chemo-Therapy Resistance

Hypoxia is a well-known characteristic of the tumor microenvironment which significantly influences cancer development and is closely linked to unfavorable outcomes. Long noncoding RNAs (lncRNAs), which are part of the noncoding genome, have garnered increasing attention because of their varied functions in tumor metastasis. Long noncoding RNAs (lncRNAs) are defined as noncoding RNAs which are longer than 200 nucleotides, and they regulate diverse cellular processes by modulating gene expression at the transcriptional, post-transcriptional and epigenetic levels. Hypoxia is a well-established environmental factor which enhances the metastasis of solid tumors. Epithelial-mesenchymal transition (EMT) represents one of the key mechanisms triggered by hypoxia which contributes to metastasis. Numerous lncRNAs have been identified as being upregulated by hypoxia. These lncRNAs significantly contribute toward cancer cell migration, invasion and metastasis. Recent studies have identified a crucial role for these hypoxia-induced lncRNAs in chemotherapy resistance. These hypoxia-related lncRNAs can be plausible therapeutic targets for devising effective cancer therapies.

Discovery of paradoxical genes: reevaluating the prognostic impact of overexpressed genes in cancer

Oncogenes are typically overexpressed in tumor tissues and often linked to poor prognosis. However, recent advancements in bioinformatics have revealed that many highly expressed genes in tumors are associated with better patient outcomes. These genes, which act as tumor suppressors, are referred to as "paradoxical genes." Analyzing The Cancer Genome Atlas (TCGA) confirmed the widespread presence of paradoxical genes, and KEGG analysis revealed their role in regulating tumor metabolism. Mechanistically, discrepancies between gene and protein expression-affected by pre- and post-transcriptional modifications-may drive this phenomenon. Mechanisms like upstream open reading frames and alternative splicing contribute to these inconsistencies. Many paradoxical genes modulate the tumor immune microenvironment, exerting tumor-suppressive effects. Further analysis shows that the stage- and tumor-specific expression of these genes, along with their environmental sensitivity, influence their dual roles in various signaling pathways. These findings highlight the importance of paradoxical genes in resisting tumor progression and maintaining cellular homeostasis, offering new avenues for targeted cancer therapy.

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.

Hypoxia-triggered ERRα acetylation enhanced its oncogenic role and promoted progression of renal cell carcinoma by coordinating autophagosome-lysosome fusion

Estrogen-related receptor α (ERRα) is dysregulated in many types of cancer and exhibits oncogenic activity by promoting tumorigenesis and metastasis of cancer cells. However, its defined role in renal cell carcinoma (RCC) has not been fully elucidated. To reveal the biological function of ERRα and determine the underlying regulatory mechanism in RCC, the quantitative proteomics analysis and mechanism investigation were conducted. The results demonstrated that ERRα promoted the proliferation and tumorigenesis of RCC cells by maintaining lysosome-dependent autophagy flux. ERRα inhibition impaired the transcriptional expression of LAMP2 and VAMP8 and blocked the fusion of autophagosomes with lysosomes, causing the impairment of the autophagy-lysosome pathway and tumor repression in RCC. Moreover, VHL mutant-induced hyperactive hypoxia signaling in RCC triggered p300/CBP-mediated acetylation at the DNA-binding domain of ERRα, and this acetylation promoted its affinity toward targeting DNA and Parkin-mediated ubiquitination and proteasome-dependent degradation. This regulatory model enhanced ERRα transactivation on the expression of LAMP2 and VAMP8, which then maintained autophagy flux and RCC progression. Pharmaceutical inhibition on ERRα acetylation-mediated autophagy-lysosome pathway led to growth repression and sunitinib sensitivity of RCC cells. Taken together, this study uncovered a novel regulatory mechanism of acetylation contributing to the transcriptional performance and the oncogenic role of ERRα in RCC progression by modulating the autophagy-lysosome pathway. These findings might provide a novel approach for the clinical diagnosis and resolution of sunitinib resistance of RCC.

Ferroptosis and its relationship with cancer

Marked by iron buildup and lipid peroxidation, ferroptosis is a relatively new regulatory cell death (RCD) pathway. Many diseases like cancer, myocardial ischemia-reperfusion injury (MIRI), neurological disorders and acute renal failure (AKI) are corelated with ferroptosis. The main molecular processes of ferroptosis discovered yet will be presented here, along with the approaches in which it interacts with tumour-associated signaling pathways and its uses in systemic therapy, radiation therapy, and immunotherapy managing tumors.

Systematic and comprehensive insights into HIF-1 stabilization under normoxic conditions: implications for cellular adaptation and therapeutic strategies in cancer

Hypoxia-inducible factors (HIFs) are essential transcription factors that orchestrate cellular responses to oxygen deprivation. HIF-1α, as an unstable subunit of HIF-1, is usually hydroxylated by prolyl hydroxylase domain enzymes under normoxic conditions, leading to ubiquitination and proteasomal degradation, thereby keeping low levels. Instead of hypoxia, sometimes even in normoxia, HIF-1α translocates into the nucleus, dimerizes with HIF-1β to generate HIF-1, and then activates genes involved in adaptive responses such as angiogenesis, metabolic reprogramming, and cellular survival, which presents new challenges and insights into its role in cellular processes. Thus, the review delves into the mechanisms by which HIF-1 maintains its stability under normoxia including but not limited to giving insights into transcriptional, translational, as well as posttranslational regulation to underscore the pivotal role of HIF-1 in cellular adaptation and malignancy. Moreover, HIF-1 is extensively involved in cancer and cardiovascular diseases and potentially serves as a bridge between them. An overview of HIF-1-related drugs that are approved or in clinical trials is summarized, highlighting their potential capacity for targeting HIF-1 in cancer and cardiovascular toxicity related to cancer treatment. The review provides a comprehensive insight into HIF-1's regulatory mechanism and paves the way for future research and therapeutic 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.

Metabolic Reprogramming in Cancer: Implications for Immunosuppressive Microenvironment

Cancer is a complex and heterogeneous disease characterised by uncontrolled cell growth and proliferation. One hallmark of cancer cells is their ability to undergo metabolic reprogramming, which allows them to sustain their rapid growth and survival. This metabolic reprogramming creates an immunosuppressive microenvironment that facilitates tumour progression and evasion of the immune system. In this article, we review the mechanisms underlying metabolic reprogramming in cancer cells and discuss how these metabolic alterations contribute to the establishment of an immunosuppressive microenvironment. We also explore potential therapeutic strategies targeting metabolic vulnerabilities in cancer cells to enhance immune-mediated anti-tumour responses. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT02044861, NCT03163667, NCT04265534, NCT02071927, NCT02903914, NCT03314935, NCT03361228, NCT03048500, NCT03311308, NCT03800602, NCT04414540, NCT02771626, NCT03994744, NCT03229278, NCT04899921.

Belzutifan plus cabozantinib as first-line treatment for patients with advanced clear-cell renal cell carcinoma (LITESPARK-003): an open-label, single-arm, phase 2 study

BACKGROUND

Belzutifan, a first-in-class HIF-2α inhibitor, has shown antitumour activity as monotherapy and in combination with cabozantinib in patients with previously treated advanced kidney cancer. The phase 2 LITESPARK-003 study was designed to determine the antitumour activity and safety of belzutifan in combination with cabozantinib in patients with advanced clear-cell renal cell carcinoma that was previously untreated (cohort 1) or previously treated with immunotherapy (cohort 2). Here, we report results from cohort 1 of this clinical trial.

METHODS

LITESPARK-003 is an open-label, single-arm, phase 2 study at ten hospitals and cancer centres in the USA. In cohort 1, eligible patients were at least 18 years of age, had an Eastern Cooperative Oncology Group performance status of 0 or 1, and had received no previous systemic therapy for locally advanced or metastatic renal cell carcinoma. Patients received belzutifan 120 mg orally once daily and cabozantinib 60 mg orally once daily until unacceptable adverse events, disease progression, or patient withdrawal. The primary endpoint was investigator-assessed confirmed objective response according to Response Evaluation Criteria in Solid Tumors version 1.1. Antitumour activity and safety were assessed in all patients who received at least one dose of study treatment. This trial is registered with ClinicalTrials.gov, NCT03634540, and is ongoing.

FINDINGS

Between Sept 27, 2018, and Jan 10, 2023, we screened 138 patients for eligibility, and 50 (36%) were enrolled and assigned to cohort 1. The median age was 64 years (IQR 57-72). 40 (80%) of 50 patients were male and ten (20%) were female. 48 (96%) patients were White, one (2%) patient was Black or African American, and one (2%) was of a race in the other category. As of the data cutoff (May 15, 2023), median follow-up was 24·3 months (IQR 13·9-32·0). 35 (70%, 95% CI 55-82) of 50 patients had a confirmed objective response, including four (8%) who had a complete response and 31 (62%) who had a partial response. The most frequent grade 3-4 treatment-related adverse events were hypertension (six [12%] patients), anaemia (five [10%] patients), and fatigue (four [8%] patients). Seven (14%) of 50 patients had serious treatment-related adverse events. No treatment-related deaths occurred.

INTERPRETATION

Belzutifan plus cabozantinib has promising antitumour activity in treatment-naive patients with advanced clear-cell renal cell carcinoma and further investigation of an HIF-2α inhibitor in combination with a multitargeted tyrosine kinase inhibitor as a treatment option in this population is warranted.

FUNDING

Merck Sharp & Dohme LLC, a subsidiary of Merck & Co, Inc, Rahway, NJ, USA, and the National Cancer Institute.

Inhibitory effects of circR-127aa on gastric cancer progression and tumor growth

This study investigates the function of a newly identified 127-amino acid peptide, circR-127aa, encoded by hsa_circ_0075402 (circRACK1), in gastric cancer (GC), a condition with significant prevalence in China. Utilizing a comprehensive analysis of circular RNA (circRNA) ribosome profiling data alongside experimental validations through mass spectrometry, Western blot, and immunofluorescence, we demonstrate that circR-127aa Inhibits Malignant Phenotypes and suppresses tumor growth in nude mice models. Significantly, the interaction of circR-127aa with Vimentin, a crucial element in actin-actin-cytoskeletal remodeling, indicates that circR-127aa functions as a tumor suppressor by facilitating the ubiquitination of Vimentin. These findings advance our comprehension of gastric cancer (GC) progression and propose circR-127aa as a promising therapeutic target and biomarker in the management of GC.

Covalent assembly-based two-photon fluorescent probes for in situ visualizing nitroreductase activities: From cancer cells to human cancer tissues

Nitroreductase (NTR) is widely regarded as a biomarker whose enzymatic activity correlates with the degree of hypoxia in solid malignant tumors. Herein, we utilized 2-dimethylamino-7-hydroxynaphthalene as fluorophore linked diverse nitroaromatic groups to obtain four NTR-activatable two-photon fluorescent probes based on covalent assembly strategy. With the help of computer docking simulation and in vitro assay, the sulfonate-based probe XN3 was proved to be able to identify NTR activity with best performances in rapid response, outstanding specificity, and sensitivity in comparison with the other three probes. Furthermore, XN3 could detect the degree of hypoxia by monitoring NTR activity in kinds of cancer cells with remarkable signal-to-noise ratios. In cancer tissue sections of the breast and liver in mice, XN3 had the ability to differentiate between healthy and tumorous tissues, and possessed excellent fluorescence stability, high tissue penetration and low tissue autofluorescence. Finally, XN3 was successfully utilized for in situ visualizing NTR activities in human transverse colon and rectal cancer tissues, respectively. The findings suggested that XN3 could directly identify the boundary between cancer and normal tissues by monitoring NTR activities, which provides a new method for imaging diagnosis and intraoperative navigation of tumor tissue.

A novel lineage-tracing tool reveals that hypoxic tumor cells drive tumor relapse after radiotherapy

PURPOSE

Tumor hypoxia imposes a main obstacle to the efficacy of anti-cancer therapy. Understanding the cellular dynamics of individual hypoxic cells before, during and post-treatment has been hampered by the technical inability to identify and trace these cells over time.

METHODS AND MATERIALS

Here, we present a novel lineage-tracing reporter for hypoxic cells based on the conditional expression of a HIF1a-CreERT2-UnaG biosensor that can visualize hypoxic cells in a time-dependent manner and trace the fate of hypoxic cells over time. We combine this system with multiphoton microscopy, flow cytometry, and immunofluorescence to characterize the role of hypoxic cells in tumor relapse after irradiation in H1299 tumor spheroids and in vivo xenografts.

RESULTS

We validate the reporter in monolayer cultures and we show that tagged cells colocalize in spheroids and human tumor xenografts with the hypoxic marker pimonidazole. We found that irradiation of H1299-HIFcreUnaG spheroids leads to preferential outgrowth of cells from the hypoxic core. Similarly, in xenografts tumors, although initially UnaG-positive-cells coincide with pimonidazole-positive tumor areas and they are merely quiescent, upon irradiation UnaG-positive cells enrich in regrowing tumors and are mainly proliferative.

CONCLUSIONS

Collectively, our data provide clear evidence that the hypoxic cells drive tumor relapse after irradiation.

Crosstalk between pancreatic cancer and adipose tissue: Molecular mechanisms and therapeutic implications

The incidence rate of pancreatic cancer, a fatal illness with a meager 5-year survival rate, has been on the rise in recent times. When individuals accumulate excessive amounts of adipose tissue, the adipose organ becomes dysfunctional due to alterations in the adipose tissue microenvironment associated with inflammation and metabolism. This phenomenon may potentially contribute to the aberrant accumulation of fat that initiates pancreatic carcinogenesis, thereby influencing the disease's progression, resistance to treatment, and metastasis. This review presents a summary of the impact of pancreatic steatosis, visceral fat, cancer-associated adipocytes and lipid diets on the advancement of pancreatic cancer, as well as the reciprocal effects of pancreatic cancer on adipose tissue. Understanding the molecular mechanisms underlying the relationship between dysfunctional adipose tissue and pancreatic cancer better may lead to the discovery of new therapeutic targets for the disease's prevention and individualized treatment. This is especially important given the rising global incidence of obesity, which will improve the pancreatic cancer treatment options that are currently insufficient.

PLGA-Nano-Encapsulated Disulfiram Inhibits Cancer Stem Cells and Targets Non-Small Cell Lung Cancer In Vitro and In Vivo

Cancer stem cells (CSCs) play a key role in non-small cell lung cancer (NSCLC) chemoresistance and metastasis. In this study, we used two NSCLC cell lines to investigate the regulating effect of hypoxia in the induction and maintenance of CSC traits. Our study demonstrated hypoxia-induced stemness and chemoresistance at levels comparable to those in typical CSC sphere culture. Activation of the NF-κB pathway (by transfection of NF-κB-p65) plays a key role in NSCLC CSCs and chemoresistance. Disulfiram (DS), an anti-alcoholism drug, showed a strong in vitro anti-CSC effect. It blocked cancer cell sphere reformation and clonogenicity, synergistically enhanced the cytotoxicity of four anti-NSCLC drugs (doxorubicin, gemcitabine, oxaliplatin and paclitaxel) and reversed hypoxia-induced resistance. The effect of DS on CSCs is copper-dependent. A very short half-life in the bloodstream is the major limitation for the translation of DS into a cancer treatment. Our team previously developed a poly lactic-co-glycolic acid (PLGA) nanoparticle encapsulated DS (DS-PLGA) with a long half-life in the bloodstream. Intra venous injection of DS-PLGA in combination with the oral application of copper gluconate has strong anticancer efficacy in a metastatic NSCLC mouse model. Further study may be able to translate DS-PLGA into cancer applications.

The efficacy and safety of belzutifan inhibitor in patients with advanced or metastatic clear cell renal cell carcinoma: a meta-analysis

BACKGROUND

The belzutifan is a hypoxia inducible factor-2 alpha (HIF-2α) inhibitor for the treatment of advanced or metastatic clear cell renal cell carcinoma (mccRCC) and has exhibited good safety and efficacy in clinical trials. We conducted a meta-analysis of relevant studies to further clarify the efficacy and safety of belzutifan for the treatment of mccRCC.

METHODS

Multiple databases and abstracts from major scientific meetings were systematically reviewed for eligible articles published before June 1, 2024. The following outcomes were analyzed: objective response rate (ORR), disease control rate (DCR), median duration of response (mDOR), median progression-free survival (mPFS), median overall survival (mOS), and treatment-related adverse events (TRAes). 426 records were reviewed, and data were extracted by at least two individuals.

RESULTS

Seven studies involving 715 patients were included in this meta-analysis. The pooled ORR was 34% (95% confidence interval [CI]: 23-46%), the DCR was 79% (95% CI: 66-90%), the mDOR was 21.8 months (95% CI: 14.82-28.78), and the mPFS time was 8.8 months (95% CI: 6.15-11.44). The pooled incidence of grade 3-5 TRAes was 46%, and the most common TRAe was anemia. Further subgroup analysis revealed that, compared with belzutifan monotherapy, the combination of belzutifan with tyrosine kinase inhibitors (TKIs) as second- or later-line therapy was associated with a statistically significant increase in the ORR. Toxicity was also greater with combined inhibition therapy.

CONCLUSIONS

Our meta-analysis revealed moderate antitumor activity and a manageable safety profile of the inhibitor belzutifan in patients with mccRCC.

Deciphering ferroptosis in critical care: mechanisms, consequences, and therapeutic opportunities

Ischemia-reperfusion injuries (IRI) across various organs and tissues, along with sepsis, significantly contribute to the progression of critical illnesses. These conditions disrupt the balance of inflammatory mediators and signaling pathways, resulting in impaired physiological functions in human tissues and organs. Ferroptosis, a distinct form of programmed cell death, plays a pivotal role in regulating tissue damage and modulating inflammatory responses, thereby influencing the onset and progression of severe illnesses. Recent studies highlight that pharmacological agents targeting ferroptosis-related proteins can effectively mitigate oxidative stress caused by IRI in multiple organs, alleviating associated symptoms. This manuscript delves into the mechanisms and signaling pathways underlying ferroptosis, its role in critical illnesses, and its therapeutic potential in mitigating disease progression. We aim to offer a novel perspective for advancing clinical treatments for critical illnesses.

Pharmacological inhibition of HIF2 protects against bone loss in an experimental model of estrogen deficiency

Estrogen deficiency, which is linked to various pathological conditions such as primary ovarian insufficiency and postmenopausal osteoporosis, disrupts the delicate balance between bone formation and resorption. This imbalance leads to bone loss and an increased risk of fractures, primarily due to a significant reduction in trabecular bone mass. Trabecular osteoblasts, the cells responsible for bone formation within the trabecular compartment, originate from skeletal progenitors located in the bone marrow. The microenvironment of the bone marrow contains hypoxic (low oxygen) regions, and the hypoxia-inducible factor-2α (HIF2) plays a crucial role in cellular responses to these low-oxygen conditions. This study demonstrates that the loss of HIF2 in skeletal progenitors and their derivatives during development enhances trabecular bone mass by promoting bone formation. More importantly, PT2399, a small molecule that specifically inhibits HIF2, effectively prevents trabecular bone loss in ovariectomized adult mice, a model for estrogen-deficient bone loss. Both the genetic and pharmacological approaches result in an increase in osteoblast number, which is linked to the expansion of the pool of skeletal progenitor cells. This expansion either by loss or inhibition of HIF2 uncovers a pivotal mechanism for increasing osteoblast numbers and bone formation, resulting in greater trabecular bone mass.

Maternal-fetal mechanisms underlying adaptation to hypoxia during early pregnancy

During the process of implantation, the embryo first attaches to the uterine epithelium and then invades the underlying stroma, resulting in the transformation of the stroma into a secretory tissue that surrounds the embryo. An intricate dialogue allows the developing embryo and the maternal tissue to be in constant communication with each other. In many mammals, including humans, embryo implantation and early pregnancy events take place in a low-oxygen environment regulated by hypoxia-inducible transcription factors. The mechanisms by which maternal and embryonic tissue compartments adapt to hypoxia are essential for the success of pregnancy outcomes. In this review we highlight recent work describing signaling pathways that operate in the hypoxic uterus to facilitate embryo implantation and promote the successful establishment of pregnancy.

YAP1 Overexpression Enhances the Aerobic Glycolysis Process via Suppression of EGLN2 in Pancreatic Ductal Adenocarcinoma

BACKGROUND

Pancreatic ductal adenocarcinoma (PDAC) is one of the most aggressive diseases and has remarkably high mortality rates. In recent years, altered metabolism has been shown to contribute to the maintenance of pancreatic cancer malignancies. However, the molecular mechanism underlying glucose metabolism reprogramming remains elusive. The aim of this study was to elucidate the role of Yes-associated protein (YAP1), an important effector of the Hippo pathway, in the regulation of aerobic glycolysis in pancreatic cancer. Moreover, the contributions of YAP1 and its associated glycolytic enzymes to prognosis were assessed via The Cancer Genome Atlas (TCGA) dataset.

METHODS

YAP1 expression was silenced by short hairpin RNA (shRNA), and its effects on glycolytic activity and mitochondrial respiration were analysed via Agilent Seahorse XF Analysers. The effects of YAP1 on hypoxia-inducible factor-1α (HIF-1α) and its transcriptional activity on glycolytic genes were examined via shRNA-mediated silencing of YAP1. The underlying mechanism by which YAP1 controls the HIF-1α protein level was analysed by exploring the interaction between YAP1 and egg-laying-defective nine family (EGLN) members, which are well-established regulators of the HIF-1α protein level. Finally, the effects of YAP1, EGLN and glycolytic genes on prognosis were analysed via TCGA dataset.

RESULTS

We found that silencing YAP1 expression inhibited anabolic glycolysis in pancreatic cancer cells. YAP1 was demonstrated to regulate the HIF-1α protein level, transcriptional activity and the expression of HIF-1α-targeted glycolytic genes. In-depth analysis demonstrated that EGLN2, a modulator of the HIF-1α protein level, was a direct target of YAP1. Low EGLN2 expression was associated with a poor prognosis. By analysing TCGA dataset and performing immunohistochemical staining, we demonstrated that YAP1 expression was negatively correlated with EGLN2 expression at the mRNA level and protein levels.

CONCLUSIONS

The present study demonstrated that YAP1 positively regulates aerobic glycolysis by inhibiting EGLN2 expression, which results in an increased HIF-1α protein level and transcriptional activity. YAP1 was positively regulated and significantly correlated with HIF-1α-targeted glycolytic genes, including glucose transporter type 1(GLUT1), hexokinase2 (HK2) and lactate dehydrogenase A (LDHA). Elevated YAP1 expression and concomitant downregulation of EGLN2 contributed to poor survival in patients with pancreatic cancer. Our results suggest that YAP1 may be a promising predictive marker and treatment target for human pancreatic cancer.

Role of Interleukins in Pancreatic Cancer: A Literature Review

PURPOSE

This review article summarizes the pathophysiological aspects of interleukins (ILs) including IL-1, IL-2, IL-3, IL-4, IL-5, IL-6, IL-7, IL-8, IL-9, and IL-10 in pancreatic cancer (PC).

METHODS

Science Direct, PubMed, and Google Scholar were used for the literature review. The search was conducted until August 12, 2024, and particular keywords such as "Pancreatic Cancer," "Interleukins," "Pathophysiological Aspects," "Immunosuppression," "Invasiveness," and "Metastasis" were used. Focusing on interleukins related to pancreatic cancer, 61 original studies were included: 32 studies for human patients, 16 studies for animal models, and 13 studies for both animal models and human patients. All types of PC were considered. The timeframe of 1991 to 2024 was chosen for clinical studies.

RESULTS

In epithelial pancreatic tumors, IL-1 is a major inflammation factor. Serum concentrations of soluble interleukin-2-receptor were considerably greater in patients with PC and chronic pancreatitis than in healthy individuals. In comparison to controls, pancreatic cancer patients had considerably greater levels of macrophage colony-stimulating factor and significantly lower levels of stem cell factor and IL-3. The tissues and cells of pancreatic cancer have higher concentrations of IL-4 receptors. IL-5 has a role in the accumulation of pancreatic fibrosis. For individuals with pancreatic ductal adenocarcinoma (PDAC), a high serum level of IL-6 may be a separate risk factor for the development of widespread liver metastases. PDAC patients' peripheral blood mononuclear cells exhibit a substantial upregulation of IL-7 receptor. The role of IL-8 in the growth and spread of PC in humans. The miR-200a/β-catenin axis may be the mechanism by which IL-9 stimulates the proliferation and metastasis of PC cells. Blocking IL-10 in the local microenvironment appears to result in a significant reversal of tumor-induced immunosuppression.

CONCLUSION

The article concludes that interleukins 1, 2, 3, 4, 5, 6, 7, 8, 9, and 10 played significant roles in the pathogenesis of PC.

Non-Susceptibility Gene Variants in Head and Neck Paragangliomas

Head and neck paragangliomas (HNPGLs) are rare neoplasms that, along with pheochromocytomas and extra-adrenal paragangliomas, are associated with inherited mutations in at least 12 susceptibility genes in approximately 40% of cases. However, due to the rarity of HNPGLs, only a series of small-scale studies and individual cases have reported mutations in additional genes that may be involved in tumorigenesis. Consequently, numerous disease-causing mutations and genes responsible for the pathogenesis of HNPGLs remain poorly investigated. The aim of this study was to gain a deeper understanding of the genetic basis of HNPGLs by focusing on variants in genes that were not previously identified as well-known drivers. A whole-exome data analysis was conducted on a representative set of 152 HNPGLs. In 30% of the tumors examined, 53 potentially deleterious variants were identified in 36 different genes. The analysis identified pathogenic or likely pathogenic variants in the ARNT, IDH2, L2HGDH, MYH3, PIK3CA, and TERT genes. A functional network analysis of the mutated genes revealed numerous associations and a list of metabolic pathways (e.g., the TCA cycle, carbon metabolism, pyruvate metabolism, etc.) and signaling pathways (e.g., HIF1, PI3K-Akt, FoxO, AMPK, MAPK, etc.) that may play an important role in the development of HNPGLs. The identified range of genetic alterations affecting multiple genes and, potentially, influencing diverse cellular pathways provides an enhanced molecular genetic characterization of HNPGLs.

EHD1 promotes breast cancer metastasis through upregulating HIF2a expression via activating mTOR pathway

The multistep dynamic process of metastasis is the primary cause of breast cancer deaths. C-terminal Eps15-homology domain-containing protein 1 (EHD1), a translocator associated with endocytic recycling, has been implicated in various oncogenic processes. However, the precise molecular mechanisms of EHD1-induced breast cancer metastases remain largely unexplored. Here we found that the upregulation of EHD1 in breast cancer was positively associated with distant lymph node metastasis in patients. Meanwhile, EHD1 promoted epithelial-mesenchymal transition (EMT), invasion, and metastasis of breast cancer cells in both two-dimensional (2D) and three-dimensional (3D) culture models in vitro, as well as in vivo. Remarkably, EHD1 can activate the AKT-mTOR pathway to upregulate the protein expression of hypoxia-inducible factor 2α (HIF2α) under normoxic conditions and subsequently enhance the invasive and metastatic breast cancer. Our findings indicated EHD1 as a new regulator of HIF2α and a potential therapeutic target for inhibiting breast cancer metastasis.