BAP1 is a novel regulator of HIF-1α

Advances in plant oxygen sensing: endogenous and exogenous mechanisms

Oxygen is essential for the biochemical processes that sustain life in eukaryotic organisms. Although plants produce oxygen through photosynthesis, they often struggle to survive in low-oxygen environments, such as during flooding or submergence. To endure these conditions, they must reprogram their developmental and metabolic networks, and the adaptation process involves the continuous detection of both exogenous hypoxic signals and endogenous oxygen gradients. Recent research has significantly advanced our understanding of how plants respond to both endogenous and exogenous hypoxia signals. In this review, we explore advancements in both areas, comparing them to responses in animals, with a primary focus on how plants perceive and respond to exogenous hypoxic conditions, particularly those caused by flooding or submergence, as well as the hypoxia signaling pathways in different crops. Additionally, we discuss the interplay between endogenous and exogenous hypoxia signals in plants. Finally, we discuss future research directions aimed at improving crop resilience to flooding by integrating the perception and responses to both endogenous and exogenous signals. Through these efforts, we aspire to contribute to the development of crop varieties that are not only highly resistant but also experience minimal growth and yield penalties, thereby making substantial contributions to agricultural science.

Chromosomal 3p loss and 8q gain drive vasculogenic mimicry via HIF-2α and VE-cadherin activation in uveal melanoma

Uveal melanoma (UM) is the most common primary intraocular malignant tumor in adults and is where Vasculogenic Mimicry (VM) was first described. VM enables aggressive cancer cells to independently form blood networks, complicating treatment for patients exhibiting VM. Previous studies linked VE-Cadherin phosphorylation at Y658 to gene expression via Focal Adhesion Kinase (FAK), enhancing the Kaiso/β-catenin/TCF-4 complex associated with VE-Cadherin and thereby promoting VM. Recently, an allosteric HIF-2α inhibitor (Belzutifan) was FDA-approved for VHL-associated ccRCCs. In this research, we elucidate the primary causes of VM formation in UM patients with chromosome 3p loss and chromosome 8q gain, identifying VHL, BAP1, and FAK as important factors driving VM and worsening prognosis. These factors promote abnormal activation of HIF-2α and VE-Cadherin under basal hypoxic conditions, leading to VM formation. Cytoscan 750k experiments on the MUM 2B cell line reveal a loss of chromosome 3p, where the VHL, BAP1, and CTNNB1 genes are located, and a gain of chromosome 8q (FAK), whereas the MUM 2C cell line shows a gain of chromosome 3p. This provides an outstanding cross-sectional model from patient samples to established cell lines for VM studies. LC-MS experiments demonstrate that VE-Cad/ENG expression is related to FAK activity in UM cell lines. Finally, using a combination of Belzutifan (HIF-2α inhibitor) and FAK inhibitor (FAKi), we observed a significant reduction in UM xenografts. Our results lead us to propose combining Belzutifan and FAKi as a personalized treatment strategy for UM patients. This approach inhibits VM formation and counters the initial hypoxic conditions resulting from chromosome 3p loss and chromosome 8q gain in UM patients, instilling confidence in the potential of this treatment strategy.

Spring viremia of carp virus infection induces hypoxia response in zebrafish by stabilizing hif1α

The hypoxia signaling pathway controls hypoxia adaptation and tolerance of organisms, which is regulated by multiple mechanisms. Viral infection elicits various pathophysiological responses in the host. However, whether viral infection can affect the hypoxia response is not yet fully understood. In this study, we found that Spring viremia of carp virus (SVCV) infection in zebrafish caused symptoms similar to those in zebrafish under hypoxic conditions. Further assays indicated that SVCV infection activated the hypoxia signaling pathway in zebrafish. In addition, SVCV infection caused increased glycolysis and reactive oxygen species (ROS) levels in cells. Mechanistically, SVCV-G protein interacted with hif1α-a/b and attenuated their K48-linked polyubiquitination, leading to their stabilization and subsequent enhancement of target gene expression. Moreover, treatment with the HIF1α-specific inhibitor PX478 enhanced the antiviral ability against SVCV infection in zebrafish and zebrafish cells. This study reveals a relationship between SVCV infection and the hypoxia signaling pathway in fish and provides a strategy for reducing the damage of viral disease in the aquaculture industry.

IMPORTANCE

Viral infection triggers various pathophysiological responses in the host. The hypoxia signaling pathway controls hypoxia adaptation and tolerance of organisms. However, whether viral infection can affect the hypoxia response is not yet fully understood. This study showed that Spring viremia of carp virus (SVCV) infection activated the hypoxia signaling pathway and induced a hypoxia response. The SVCV-G protein interacted with hif1α-a/b and reduced their K48-linked polyubiquitination, leading to their stabilization and subsequent enhancement of target gene expression. Additionally, treatment with the HIF1α-specific inhibitor PX478 enhanced the antiviral ability against SVCV infection in zebrafish and zebrafish cells. Our findings not only reveal a relationship between SVCV infection and the hypoxia signaling pathway in fish but also provide a strategy for reducing the damage of viral disease in the aquaculture industry.

Modified Zuojin pill alleviates gastric precancerous lesions by inhibiting glycolysis through the HIF-1α pathway

BACKGROUND

Gastric precancerous lesions (GPL) typically originates from chronic gastritis (CG), and the changes in glycolysis mediated by the HIF-1α pathway during the progression from CG to GPL are unclear. Modified Zuojin pill (SQQT) is a traditional Chinese herbal formula used for treating GPL. However, the underlying mechanism has not been fully elucidated.

PURPOSE

To investigate the changes in glycolysis mediated by the HIF-1α pathway during the progression from CG to GPL and whether SQQT can alleviate GPL by attenuating glycolysis through the HIF-1α pathway.

METHODS

A rat model of GPL was established, and the changes of glycolysis mediated by the HIF-1α pathway during the progression from CG to GPL were detected in 12th, 18th, 24th, and 30th weeks. The therapeutic efficacy of SQQT was evaluated through pathological changes. In vitro, the GPL cell model (MC cell) originated from GES-1 cells intervened by MNNG. The effects of SQQT on glycolysis and the HIF-1α pathway were detected in vivo and in vitro. In vitro, HIF-1α overexpression was used to confirmed that SQQT attenuated glycolysis by targeting the HIF-1α pathway.

RESULTS

Our study revealed that glycolysis mediated by the HIF-1α pathway exhibited dynamic changes in the progression from CG to GPL, characterized by sequential activation, deactivation, and reactivation. SQQT ameliorated gastric mucosal pathology and inflammation in GPL rats. Mechanistic studies revealed that SQQT alleviated glycolysis by targeting the HIF-1α pathway, and improved abnormal cellular proliferation and apoptosis. Importantly, HIF-1α overexpression blocked the effect of SQQT on glycolysis.

CONCLUSION

In the progression from CG to GPL, the HIF-1α pathway-mediated glycolysis was characterized by sequential activation, deactivation, and reactivation. SQQT attenuated glycolysis by targeting the HIF-1α pathway and improved abnormal cellular proliferation and apoptosis in the gastric mucosa, thereby exerting therapeutic effects on GPL.

Dysregulation of ubiquitination modification in renal cell carcinoma

Renal cell carcinoma (RCC) is a malignant tumor of the renal tubular epithelial cells with a relatively high incidence rate worldwide. A large number of studies have indicated that dysregulation of the ubiquitination, including ubiquitination and dysregulation, is associated with the occurrence and development of RCC. This review focuses on several abnormal signaling pathways caused by E3 ligases and deubiquitinases. Additionally, we discuss research progress in RCC treatment by targeting key enzymes related to ubiquitination modifications.

A comprehensive review of PRAME and BAP1 in melanoma: Genomic instability and immunotherapy targets

In a thorough review of the literature, the complex roles of PRAME (preferentially expressed Antigen of Melanoma) and BAP1 (BRCA1-associated protein 1) have been investigated in uveal melanoma (UM) and cutaneous melanoma. High PRAME expression in UM is associated with poor outcomes and correlated with extraocular extension and chromosome 8q alterations. BAP1 mutations in the UM indicate genomic instability and a poor prognosis. Combining PRAME and BAP1 immunohistochemical staining facilitates effective risk stratification. Mechanistically, both genes are associated with genomic instability, making them promising targets for cancer immunotherapy. Hypomethylation of PRAME, specifically in its promoter regions, is critical for UM progression and contributes to epigenetic reprogramming. Additionally, miR-211 regulation is crucial in melanoma and has therapeutic potential. The way PRAME changes signaling pathways provides clues about the cause of cancer due to genomic instability related to modifications in DNA repair. Inhibition of poly(ADP-ribose) polymerase-1 (PARP-1) and PARP-2 in cells expressing PRAME could lead to potential therapeutic applications. Pathway enrichment analysis underscores the significance of PRAME and BAP1 in melanoma pathogenesis.

Prognostic implications of tenascin C in peripheral blood and primary tumours at the time of uveal melanoma diagnosis

OBJECTIVE

To examine the prognostic implication of tenascin C (TNC) in posterior uveal melanoma (UM).

DESIGN

Retrospective cohort study.

PARTICIPANTS

A total of 162 patients diagnosed with posterior UM.

METHODS

A peripheral blood sample was obtained from 82 patients at the time of UM diagnosis between 1996 and 1999. Samples were kept frozen at -80°C until the concentration of TNC was measured in 2021. Primary tumour TNC RNA sequencing data were collected from another 80 patients (The Cancer Genome Atlas cohort). Patients were separated based on median TNC values. Cumulative incidences of metastatic death (UM mortality) from competing risks data were calculated as well as Cox regression hazard ratios.

RESULTS

Patients with high and low TNC levels had tumours of similar size and American Joint Committee on Cancer stage at Bonferroni-corrected significance levels. The exception was a significantly smaller tumour diameter in patients with high serum TNC levels (p = 0.003). In competing risks analysis, patients with high serum TNC levels (≥7 ng/mL) had a higher UM mortality rate (44% vs 17% at 20 years; p = 0.008). Similarly, patients with higher primary tumour TNC RNA levels (≥1 transcripts per million) had higher UM mortality (83% vs 27% at 5 years; p = 0.003). In multivariate Cox regressions, TNC levels in peripheral blood and primary tumours were predictors of metastatic death independent of American Joint Committee on Cancer stage.

CONCLUSIONS

TNC is a prognostic biomarker in UM. At the time of primary tumour diagnosis, it is measured in higher levels in both peripheral blood and tumour tissue from patients who will eventually suffer from metastatic death.

Deubiquitinating enzyme mutagenesis screens identify a USP43-dependent HIF-1 transcriptional response

The ubiquitination and proteasome-mediated degradation of Hypoxia Inducible Factors (HIFs) is central to metazoan oxygen-sensing, but the involvement of deubiquitinating enzymes (DUBs) in HIF signalling is less clear. Here, using a bespoke DUBs sgRNA library we conduct CRISPR/Cas9 mutagenesis screens to determine how DUBs are involved in HIF signalling. Alongside defining DUBs involved in HIF activation or suppression, we identify USP43 as a DUB required for efficient activation of a HIF response. USP43 is hypoxia regulated and selectively associates with the HIF-1α isoform, and while USP43 does not alter HIF-1α stability, it facilitates HIF-1 nuclear accumulation and binding to its target genes. Mechanistically, USP43 associates with 14-3-3 proteins in a hypoxia and phosphorylation dependent manner to increase the nuclear pool of HIF-1. Together, our results highlight the multifunctionality of DUBs, illustrating that they can provide important signalling functions alongside their catalytic roles.

Understanding the intersection between placental development and cancer: Lessons from the tumor suppressor BAP1

The placenta, a pivotal organ in mammalian reproduction, allows nutrient exchange and hormonal signaling between the mother and the developing fetus. Understanding its molecular intricacies is essential for deciphering normal embryonic development and pathological conditions such as tumorigenesis. Here, we explore the multifaceted role of the tumor suppressor BRCA1-associated protein 1 (BAP1) in cancer and placentation. Initially recognized for its tumor-suppressive properties, BAP1 has emerged as a key regulator at the intersection of tumorigenesis and placental development. BAP1 influences crucial cellular processes such as cell death, proliferation, metabolism, and response to hypoxic conditions. By integrating insights from tumor and developmental biology, we illuminate the complex molecular pathways orchestrated by BAP1. This perspective highlights BAP1's significant impact on both cancer and placental development, and suggests novel therapeutic strategies that could improve outcomes for pregnancy disorders and cancer.

The Interplay Between the Immune System, Tumor Suppressor Genes, and Immune Senescence in Mesothelioma Development and Response to Immunotherapy

Despite efforts to ban asbestos mining and manufacturing, mesothelioma deaths in the United States have remained stable at approximately 2500 cases annually. This trend is not unique to the United States but is also a global phenomenon, associated with increased aging of populations worldwide. Although geoeconomic factors such as lack of regulations and continued asbestos manufacturing in resource-poor countries play a role, it is essential to consider biological factors such as immune senescence and increased genetic instability associated with aging. Recognizing that mesothelioma shares genetic instability and immune system effects with other age-related cancers is crucial because the impact of aging on mesothelioma is frequently assessed in the context of disease latency after asbestos exposure. Nevertheless, the long latency period, often cited as a reason for mesothelioma's elderly predominance, should not overshadow the shared mechanisms. This communication focuses on the role of immune surveillance in mesothelioma, particularly exploring the impact of immune escape resulting from altered TSG function during aging, contributing to the phylogenetic development of gene mutations and mesothelioma oncogenesis. The interplay between the immune system, TSGs, and aging not only shapes the immune landscape in mesothelioma but also contributes to the development of heterogeneous tumor microenvironments, significantly influencing responses to immunotherapy approaches and survival rates. By understanding the complex interplay between aging, TSG decline, and immune senescence, health care professionals can pave the way for more effective and personalized immunotherapies, ultimately offering hope for better outcomes in the fight against mesothelioma.

Diffuse Pleural Mesothelioma: Advances in Molecular Pathogenesis, Diagnosis, and Treatment

Diffuse pleural mesothelioma (DPM) is a highly aggressive malignant neoplasm arising from the mesothelial cells lining the pleural surfaces. While DPM is a well-recognized disease linked to asbestos exposure, recent advances have expanded our understanding of molecular pathogenesis and transformed our clinical practice. This comprehensive review explores the current concepts and emerging trends in DPM, including risk factors, pathobiology, histologic subtyping, and therapeutic management, with an emphasis on a multidisciplinary approach to this complex disease.

USP38 promotes deubiquitination of K11-linked polyubiquitination of HIF1α at Lys769 to enhance hypoxia signaling

HIF1α is one of the master regulators of the hypoxia signaling pathway and its activation is regulated by multiple post-translational modifications (PTMs). Deubiquitination mediated by deubiquitylating enzymes (DUBs) is an essential PTM that mainly modulates the stability of target proteins. USP38 belongs to the ubiquitin-specific proteases (USPs). However, whether USP38 can affect hypoxia signaling is still unknown. In this study, we used quantitative real-time PCR assays to identify USPs that can influence hypoxia-responsive gene expression. We found that overexpression of USP38 increased hypoxia-responsive gene expression, but knockout of USP38 suppressed hypoxia-responsive gene expression under hypoxia. Mechanistically, USP38 interacts with HIF1α to deubiquitinate K11-linked polyubiquitination of HIF1α at Lys769, resulting in stabilization and subsequent activation of HIF1α. In addition, we show that USP38 attenuates cellular ROS and suppresses cell apoptosis under hypoxia. Thus, we reveal a novel role for USP38 in the regulation of hypoxia signaling.

Preventive and therapeutic opportunities: targeting BAP1 and/or HMGB1 pathways to diminish the burden of mesothelioma

Mesothelioma is a cancer typically caused by asbestos. Mechanistically, asbestos carcinogenesis has been linked to the asbestos-induced release of HMGB1 from the nucleus to the cytoplasm, where HMGB1 promotes autophagy and cell survival, and to the extracellular space where HMGB1 promotes chronic inflammation and mesothelioma growth. Targeting HMGB1 inhibited asbestos carcinogenesis and the growth of mesothelioma. It is hoped that targeting HMGB1 will be a novel therapeutic strategy that benefits mesothelioma patients. Severe restrictions and/or a complete ban on the use of asbestos were introduced in the 80 and early 90s in the Western world. These measures have proven effective as the incidence of mesothelioma/per 100,000 persons is decreasing in these countries. However, the overall number of mesotheliomas in the Western world has not significantly decreased. There are several reasons for that which are discussed here: (1) the presence of asbestos in old constructions; (2) the development of rural areas containing asbestos or other carcinogenic mineral fibers in the terrain; (3) the discovery of an increasing fraction of mesotheliomas caused by germline genetic mutations of BAP1 and other tumor suppressor genes; (4) mesotheliomas caused by radiation therapy; (5) the overall increase in the population and of the fraction of older people who are much more susceptible to develop all types of cancers, including mesothelioma. In summary, the epidemiology of mesothelioma is changing, the ban on asbestos worked, there are opportunities to help mesothelioma patients especially those who develop in a background of germline mutations and there is the opportunity to prevent a mesothelioma epidemic in the developing world, where the use of asbestos is increasing exponentially. We hope that restrictive measures similar to those introduced in the Western world will soon be introduced in developing countries to prevent a mesothelioma epidemic.

The Role of Germline Mutations in Thoracic Malignancies: Between Myth and Reality

Considering the established contribution of environmental factors to the development of thoracic malignancies, the inherited susceptibility of these tumors has rarely been explored. However, the recent introduction of next-generation sequencing-based tumor molecular profiling in the real-word setting enabled us to deeply characterize the genomic background of patients with lung cancer with or without smoking-related history, increasing the likelihood of detecting germline mutations with potential prevention and treatment implications. Pathogenic germline variants have been detected in 2% to 3% of patients with NSCLC undergoing next-generation sequencing analysis, whereas the proportion of germline mutations associated with the development of pleural mesothelioma widely varies across different studies, ranging between 5% and 10%. This review provides an updated summary of emerging evidence about germline mutations in thoracic malignancies, focusing on pathogenetic mechanisms, clinical features, therapeutic implications, and screening recommendations for high-risk individuals.