Advances in Hypoxia-Inducible Factor Biology

Hypoxia-induced TRPM7 promotes glycolytic metabolism and progression in hepatocellular carcinoma

BACKGROUND

Hypoxia disrupts glucose metabolism in hepatocellular carcinoma (HCC). Transient receptor potential cation channel, subfamily M, member 7 (TRPM7) plays an ontogenetic role. Thus, we aimed to explore the regulation of TRPM7 by hypoxia-induced factor (HIF) and its underlying mechanisms in HCC.

METHODS

hypoxia was induced in multiple HCC cells using 1% O2 or CoCl2 treatment, and subsequently blocked using siRNAs targeting HIF-1α or HIF-2α as well as a HIF-1α protein synthesis inhibitor. The levels of HIF-1α and TRPM7 were assessed using quantitative PCR (qPCR) and Western blot analysis. Chromatin immunoprecipitation (ChIP) and luciferase assays were performed to observe the regulation of TRPM7 promoter regions by HIF-1α. A PCR array was utilized to screen glucose metabolism-related enzymes in HEK293 cells overexpressing TRPM7 induced by tetracycline, and then verified in TRPM7-overexpressed huh7 cells. Finally, CCK-8, transwell, scratch and tumor formation experiments in nude mice were conducted to examine the effect of TRPM7 on proliferation and metastasis in HCC.

RESULTS

Exposure to hypoxia led to increase the levels of TRPM7 and HIF-1α in HCC cells, which were inhibited by HIF-1α siRNA or enhanced by HIF-1α overexpression. HIF-1α directly bound to two hypoxia response elements (HREs) in the TRPM7 promoter. Several glycolytic metabolism-related enzymes, were simultaneously upregulated in HEK293 and huh7 cells overexpressing TRPM7 during hypoxia. In vitro and in vivo experiments demonstrated that TRPM7 promoted the proliferation and metastasis of HCC cells.

CONCLUSIONS

TRPM7 was directly transcriptionally regulated by HIF-1α, leading to glycolytic metabolic reprogramming and the promotion of HCC proliferation and metastasis in vitro and in vivo. Our findings suggest that TRPM7 might be a potential diagnostic indicator and therapeutic target for HCC.

Ganoderic acid D attenuates gemcitabine resistance of triple-negative breast cancer cells by inhibiting glycolysis via HIF-1α destabilization

BACKGROUND

Gemcitabine (GEM) resistance is the primary reason why combination chemotherapy is limited in triple-negative breast cancer (TNBC). Ganoderic acid D (GAD), a natural triterpenoid compound obtained from Ganoderma lucidum, has been shown to have antitumor activities. However, whether GAD can reverse GEM resistance in TNBC requires further investigation.

PURPOSE

This study investigated whether and how GAD could reverse GEM resistance in TNBC as an antitumor adjuvant.

METHODS

The effects of GAD on cell proliferation, cell cycle, and glycolysis were studied in vitro using a GEM-resistant (GEM-R) TNBC cell model. We enriched key pathways affected by GAD using proteomics techniques. Western blotting and qPCR were used to detect the expression of glycolysis-related genes after GAD treatment. A mouse resistance model was established using GEM-R TNBC cells, and hematoxylin-eosin staining and immunohistochemistry were used to assess the role of GAD in reversing resistance in vivo.

RESULTS

Cellular functional assays showed that GAD significantly inhibited proliferation and glucose uptake in GEM-R TNBC cells. GAD reduces HIF-1α accumulation in TNBC cells under hypoxic conditions through the ubiquitinated protease degradation pathway. Mechanistically, GAD activates the p53/MDM2 pathway, promoting HIF-1α ubiquitination and proteasomal degradation and downregulating HIF-1α-dependent glycolysis genes like GLUT1, HK2, and PKM2. Notably, GAD combined with gemcitabine significantly reduced the growth of GEM-R TNBC cells in a subcutaneous tumor model.

CONCLUSIONS

This study reveals a novel antitumor function of GAD, which inhibits glycolysis by promoting HIF-1α degradation in GEM-R TNBC cells, offering a promising therapeutic strategy for TNBC patients with GEM resistance.

The relativity analysis of hypoxia inducible factor-1α in pulmonary arterial hypertension (ascites syndrome) in broilers: a review

Ascites syndrome (AS) in broiler chickens, also known as pulmonary arterial hypertension (PAH), is a significant disease in the poultry industry. It is a nutritional metabolic disease that is closely associated with hypoxia-inducible factors and rapid growth. The rise in pulmonary artery pressure is a crucial characteristic of AS and is instrumental in its development. Hypoxia-inducible factor 1α (HIF-1α) is an active subunit of a key transcription factor in the oxygen-sensing pathway. HIF-1α plays a vital role in oxygen homeostasis and the development of pulmonary hypertension. Studying the effects of HIF-1α on pulmonary hypertension in humans or mammals, as well as ascites in broilers, can help us understand the pathogenesis of AS. Therefore, this review aims to (1) summarize the mechanism of HIF-1α in the development of pulmonary hypertension, (2) provide theoretical significance in explaining the mechanism of HIF-1α in the development of pulmonary arterial hypertension (ascites syndrome) in broilers, and (3) establish the correlation between HIF-1α and pulmonary arterial hypertension (ascites syndrome) in broilers. HIGHLIGHTSExplains the hypoxic mechanism of HIF-1α.Linking HIF-1α to pulmonary hypertension in broilers.Explains the role of microRNAs in pulmonary arterial hypertension in broilers.

A patent review on hypoxia-inducible factor (HIF) modulators (2021-2023)

INTRODUCTION

Hypoxia-inducible factor (HIF) is a central regulatory factor in detecting and adapting to cellular oxygen stress. Dysregulation of HIF is associated with various human diseases. Seven HIF modulators, including six prolyl hydroxylase (PHD) inhibitors and one HIF-2α inhibitor, have already been approved for the treatment of renal anemia and cancer, respectively.

AREAS COVERED

This review summarizes HIF modulators patented in the 2021-2023 period. This review provides an overview of HIF downregulators, including HIF-1α inhibitors, HIF-2α inhibitors, and HIF-2α degraders, as well as HIF upregulators, including PHD, FIH, and VHL inhibitors, and HIF-2α and HIF-3α agonists.

EXPERT OPINION

Efforts should be made to address the adverse clinical effects associated with approved HIF-modulating drugs, including PHD inhibitors and HIF-2α inhibitors. Identification of the specific buried cavity in the HIF-2α and an opened pocket in HIF-3α offer an avenue for designing novel modulators for HIF-2α or HIF-3α. Given the similarities observed in the binding cavities of HIF-2α and HIF-3α, it should be considered whether the approved HIF-2α inhibitors also inhibit HIF-3α. A comprehensive understanding of the HIF signaling pathway biology would lead to the development of novel small-molecule HIF modulators as innovative therapeutic approaches for a wide range of human diseases.

HIF-2α Inhibition Disrupts Leukemia Stem Cell Metabolism and Impairs Vascular Microenvironment to Enhance Chronic Myeloid Leukemia Treatment

Leukemic stem cells (LSCs) in chronic myeloid leukemia (CML) contribute to treatment resistance and disease recurrence. Metabolism regulates LSCs, but the mechanisms remain elusive. Here, we show that hypoxia-inducible factor 2α (HIF-2α) is highly expressed in LSCs in mouse and human CML and increases after tyrosine kinase inhibitor (TKI) treatment. Deletion of HIF-2α suppresses disease progression, reduces LSC numbers, and enhances the efficacy of TKI treatment in BCL-ABL-induced CML mice. Mechanistically, HIF-2α deletion reshapes the metabolic profile of LSCs, leading to increased production of reactive oxygen species (ROS) and apoptosis in CML. Moreover, HIF-2α deletion decreases vascular endothelial growth factor (VEGF) expression, thereby suppressing neovascularization in the bone marrow of CML mice. Furthermore, pharmaceutical inhibition of HIF-2α by PT2399 attenuates disease progression and improves the efficacy of TKI treatment in both mouse and human CML. Overall, our findings highlight the role of HIF-2α in controlling the metabolic state and vascular niche remodeling in CML, suggesting it is a potential therapeutic target to enhance TKI therapy.

An Overview of Cancer Biology, Pathophysiological Development and It's Treatment Modalities: Current Challenges of Cancer anti-Angiogenic Therapy

A number of conditions and factors can cause the transformation of normal cells in the body into malignant tissue by changing the normal functions of a wide range of regulatory, apoptotic, and signal transduction pathways. Despite the current deficiency in fully understanding the mechanism of cancer action accurately and clearly, numerous genes and proteins that are causally involved in the initiation, progression, and metastasis of cancer have been identified. But due to the lack of space and the abundance of details on this complex topic, we have emphasized here more recent advances in our understanding of the principles implied tumor cell transformation, development, invasion, angiogenesis, and metastasis. Inhibition of angiogenesis is a significant strategy for the treatment of various solid tumors, that essentially depend on cutting or at least limiting the supply of blood to micro-regions of tumors, leading to pan-hypoxia and pan-necrosis inside solid tumor tissues. Researchers have continued to enhance the efficiency of anti-angiogenic drugs over the past two decades, to identify their potential in the drug interaction, and to discover reasonable interpretations for possible resistance to treatment. In this review, we have discussed an overview of cancer history and recent methods use in cancer therapy, focusing on anti-angiogenic inhibitors targeting angiogenesis formation. Further, this review has explained the molecular mechanism of action of these anti-angiogenic inhibitors in various tumor types and their limitations use. In addition, we described the synergistic mechanisms of immunotherapy and anti-angiogenic therapy and summarizes current clinical trials of these combinations. Many phase III trials found that combining immunotherapy and anti-angiogenic therapy improved survival. Therefore, targeting the source supply of cancer cells to grow and spread with new anti-angiogenic agents in combination with different conventional therapy is a novel method to reduce cancer progression. The aim of this paper is to overview the varying concepts of cancer focusing on mechanisms involved in tumor angiogenesis and provide an overview of the recent trends in anti-angiogenic strategies for cancer therapy.

Fetal origins of obesity: a novel pathway of regulating appetite neurons in the hypothalamus of growth-restricted rat offspring

PURPOSE

Fetal growth restriction causes a series of sequelae, some of which, such as hyperphagia, reduced satiety and postnatal obesity, are believed to be associated with embryonic hypothalamic neurons impairment. The mechanisms underlying the linkage of fetal brain injuries to break the energy homeostasis have not been elucidated completely. Here, we aim to investigate the effect of intrauterine energy restriction on remodeling appetite neurons in the hypothalamus of fetal and postnatal infant rats.

METHODS

Low-protein (8%) diet combined with 75% energy restriction was used to establish an animal model. Rats offspring brain tissues, harvested from embryo day 18 and postnatal infant day 1, were sampled for dependent regulator analyses and master neuron assessment.

RESULTS

Growth-restricted rats showed the increased expression of Bsx and NPY in the hypothalamus as well as remodeling hypothalamic neurons differentiation compared to controls. Intriguingly, in cells cultured in vitro test, we found that activated effects of Bsx and NPY could be exacerbated by DNMT1 inhibitor.

CONCLUSIONS

In embryonic and early postnatal stage of FGR rats, we detected high concentrations of orexigenic neurons in the hypothalamus. DNMT1 activity is correlated with early embryonic neurogenesis by mediating the expression of Bsx and NPY. It may be one of the reasons for the abnormal development of the appetite regulation pathway and higher susceptibility to obesity in FGR offspring.

Fibro-adipogenic progenitors in physiological adipogenesis and intermuscular adipose tissue remodeling

Excessive accumulation of intermuscular adipose tissue (IMAT) is a common pathological feature in various metabolic and health conditions and can cause muscle atrophy, reduced function, inflammation, insulin resistance, cardiovascular issues, and unhealthy aging. Although IMAT results from fat accumulation in muscle, the mechanisms underlying its onset, development, cellular components, and functions remain unclear. IMAT levels are influenced by several factors, such as changes in the tissue environment, muscle type and origin, extent and duration of trauma, and persistent activation of fibro-adipogenic progenitors (FAPs). FAPs are a diverse and transcriptionally heterogeneous population of stromal cells essential for tissue maintenance, neuromuscular stability, and tissue regeneration. However, in cases of chronic inflammation and pathological conditions, FAPs expand and differentiate into adipocytes, resulting in the development of abnormal and ectopic IMAT. This review discusses the role of FAPs in adipogenesis and how they remodel IMAT. It highlights evidence supporting FAPs and FAP-derived adipocytes as constituents of IMAT, emphasizing their significance in adipose tissue maintenance and development, as well as their involvement in metabolic disorders, chronic pathologies and diseases. We also investigated the intricate molecular pathways and cell interactions governing FAP behavior, adipogenesis, and IMAT accumulation in chronic diseases and muscle deconditioning. Finally, we hypothesize that impaired cellular metabolic flexibility in dysfunctional muscles impacts FAPs, leading to IMAT. A deeper understanding of the biology of IMAT accumulation and the mechanisms regulating FAP behavior and fate are essential for the development of new therapeutic strategies for several debilitating conditions.

Local delivery of stem cell spheroids with protein/polyphenol self-assembling armor to improve myocardial infarction treatment via immunoprotection and immunoregulation

Stem cell therapies have shown great potential for treating myocardial infarction (MI) but are limited by low cell survival and compromised functionality due to the harsh microenvironment at the disease site. Here, we presented a Mesenchymal stem cell (MSC) spheroid-based strategy for MI treatment by introducing a protein/polyphenol self-assembling armor coating on the surface of cell spheroids, which showed significantly enhanced therapeutic efficacy by actively manipulating the hostile pathological MI microenvironment and enabling versatile functionality, including protecting the donor cells from host immune clearance, remodeling the ROS microenvironment and stimulating MSC's pro-healing paracrine secretion. The underlying mechanism was elucidated, wherein the armor protected to prolong MSCs residence at MI site, and triggered paracrine stimulation of MSCs towards immunoregulation and angiogenesis through inducing hypoxia to provoke glycolysis in stem cells. Furthermore, local delivery of coated MSC spheroids in MI rat significantly alleviated local inflammation and subsequent fibrosis via mediation macrophage polarization towards pro-healing M2 phenotype and improved cardiac function. In general, this study provided critical insight into the enhanced therapeutic efficacy of stem cell spheroids coated with a multifunctional armor. It potentially opens up a new avenue for designing immunomodulatory treatment for MI via stem cell therapy empowered by functional biomaterials.

Havoc in harmony: Unravelling the intricacies of angiogenesis orchestrated by the tumor microenvironment

Cancer cells merely exist in isolation; rather, they exist in an intricate microenvironment composed of blood vessels, signalling molecules, immune cells, stroma, fibroblasts, and the ECM. The TME provides a setting that is favourable for the successful growth and survivance of tumors. Angiogenesis is a multifaceted process that is essential for the growth, invasion, and metastasis of tumors. TME can be visualized as a "concert hall," where various cellular and non-cellular factors perform in a "symphony" to orchestrate tumor angiogenesis and create "Havoc" instead of "Harmony". In this review, we comprehensively summarized the involvement of TME in regulating tumor angiogenesis. Especially, we have focused on immune cells and their secreted factors, inflammatory cytokines and chemokines, and their role in altering the TME. We have also deciphered the crosstalk among various cell types that further aids the process of tumor angiogenesis. Additionally, we have highlighted the limitations of existing anti-angiogenic therapy and discussed various potential strategies that could be used to overcome these challenges and improve the efficacy of anti-angiogenic therapy.

Hypoxic adipose stem cell-derived exosomes carrying high-abundant USP22 facilitate cutaneous wound healing through stabilizing HIF-1α and upregulating lncRNA H19

Hypoxic preconditioning has been recognized as a promotive factor for accelerating cutaneous wound healing. Our previous study uncovered that exosomal lncRNA H19, derived from adipose-derived stem cells (ADSCs), plays a crucial role in orchestrating cutaneous wound healing. Herein, we aimed to explore whether there is a connection between hypoxia and ADSC-derived exosomes (ADSCs-exos) in cutaneous wound healing. Exosomes extracted from ADSCs under normoxic and hypoxic conditions were identified using transmission electron microscope (TEM) and particle size analysis. The effects of ADSCs-exos on the proliferation, migration, and angiogenesis of human umbilical vein endothelial cells (HUVECs) were evaluated by CCK-8, EdU, wound healing, and tube formation assays. Expression patterns of H19, HIF-1α, and USP22 were measured. Co-immunoprecipitation, chromatin immunoprecipitation, ubiquitination, and luciferase reporter assays were conducted to confirm the USP22/HIF-1α/H19 axis, which was further validated in a mice model of skin wound. Exosomes extracted from hypoxia-treated ADSCs (termed as H-ADSCs-exos) significantly increased cell proliferation, migration, and angiogenesis in H2O2-exposed HUVECs, and promoted cutaneous wound healing in vivo. Moreover, H-ADSCs and H-ADSCs-exos, which exhibited higher levels of H19, were found to be transcriptionally activated by HIF-1α. Mechanically, H-ADSCs carrying USP22 accounted for deubiquitinating and stabilizing HIF-1α. Additionally, H-ADSCs-exos improved cell proliferation, migration, and angiogenesis in H2O2-triggered HUVECs by activating USP22/HIF-1α axis and promoting H19 expression, which may provide a new clue for the clinical treatment of cutaneous wound healing.

Characterization of HIF-1α Knockout Primary Human Natural Killer Cells Including Populations in Allogeneic Glioblastoma

Enhancing immune cell functions in tumors remains a major challenge in cancer immunotherapy. Natural killer cells (NK) are major innate effector cells with broad cytotoxicity against tumors. Accordingly, NK cells are ideal candidates for cancer immunotherapy, including glioblastoma (GBM). Hypoxia is a common feature of solid tumors, and tumor cells and normal cells adapt to the tumor microenvironment by upregulating the transcription factor hypoxia-inducible factor (HIF)-1α, which can be detrimental to anti-tumor effector immune cell function, including that of NK cells. We knocked out HIF-1α in human primary NK cells using clustered regularly interspaced short palindromic repeat (CRISPR)-associated protein 9 (Cas9). Then, cellular characterizations were conducted in normoxic and hypoxic conditions. Electroporating two HIF-1α-targeting guide RNA-Cas9 protein complexes inhibited HIF-1α expression in expanded NK cells. HIF-1α knockout human NK cells, including populations in hypoxic conditions, enhanced the growth inhibition of allogeneic GBM cells and induced apoptosis in GBM-cell-derived spheroids. RNA-sequencing revealed that the cytotoxicity of HIF-1α knockout NK cells could be related to increased perforin and TNF expression. The results demonstrated that HIF-1α knockout human NK cells, including populations, enhanced cytotoxicity in an environment mimicking the hypoxic conditions of GBM. CRISPR-Cas9-mediated HIF-1α knockout NK cells, including populations, could be a promising immunotherapeutic alternative in patients with GBM.

Celastrol inhibits mouse B16-F10 melanoma cell survival by regulating the PI3K/AKT/mTOR signaling pathway and repressing HIF-1α expression

OBJECTIVE

Melanoma, with its high degree of malignancy, stands as one of the most dangerous skin cancers and remains the primary cause of death from skin cancer. With studies demonstrating the potential of traditional Chinese medicine to intervene and treat melanoma, we turned our attention to celastrol. Celastrol is a triterpene compound extracted from the traditional Chinese medicine derived from Tripterygium wilfordii. Previous studies have shown that celastrol exerts inhibitory effects on various malignant tumors, including melanoma. Hence, our goal was to clarify the impact of celastrol on cell viability, apoptosis, and cell cycle progression by elucidating its effects on the PI3K/AKT/mTOR pathway.

METHODS

CCK-8 and wound healing assays were used to determine the effect of celastrol on the viability and migration of B16-F10 cells. Changes in cell apoptosis, cell cycle, reactive oxygen species (ROS), and mitochondrial membrane potential were detected by flow cytometry. PI3K/AKT/mTOR pathway proteins and HIF-α mRNA expression in B16-F10 cells were detected by western blotting and qPCR. Moreover, the addition of a PI3K activator demonstrated that celastrol could inhibit the function of B16-F10 cells via the PI3K/AKT/mTOR pathway.

RESULTS

Celastrol inhibited the viability and migration of B16-F10 cells. Through the inhibition of the PI3K/AKT/mTOR pathway down-regulates the expression of HIF-α mRNA, thereby causing an increase of ROS in cells and a decrease in the mitochondrial membrane potential to promote cell apoptosis and cell cycle arrest. The inhibitory effect of celastrol on B16-F10 cells was further demonstrated by co-culturing with a PI3K activator.

CONCLUSION

Celastrol inhibits the function of B16-F10 cells by inhibiting the PI3K/AKT/mTOR cellular pathway and regulating the expression of downstream HIF-α mRNA.

Global research landscape and trends of cancer stem cells from 1997 to 2023: A bibliometric analysis

Cancer stem cells (CSCs) are a subset of cells with self-renewal ability and tumor generating potential. Accumulated evidence has revealed that CSCs were shown to contribute to tumorigenesis, metastasis, recurrence and resistance to chemoradiotherapy. Therefore, CSCs were regarded as promising therapeutic targets in cancer. This study is the first to reveal the development process, research hotspots, and trends of entire CSCs research field through bibliometric methods. All relevant publications on CSCs with more than 100 citations (notable papers) and the 100 most cited papers (top papers) during 1997 to 2023 were extracted and analyzed. Cancer research published the largest number of papers (184 papers). The USA accounted for the most publications (1326 papers). Rich, JN was the author with the most publications (56 papers) and the highest M-index (3.111). The most contributive institution was the University of Texas System (164 papers). Before 2007, research mainly focused on the definition and recognition of CSCs. Between 2007 and 2016, with the emergence of the terms such as "sonic hedgehog," "metabolism," "oxidative phosphorylation," and "epithelial mesenchymal transition," research began to shift toward exploring the mechanisms of CSCs. In 2016, the focus transitioned to the tumor microenvironment and the ecological niches. The analysis of papers published in major journals since 2021 showed that "transcription," "inhibition," and "chemoresistance" emerged as new focused issues. In general, the research focus has gradually shifted from basic biology to clinical transformation. "Tumor microenvironment" and "chemo-resistance" should be given more attention in the future.

Circulating microRNA Analysis in a Prospective Co-clinical Trial Identifies MIR652-3p as a Response Biomarker and Driver of Regorafenib Resistance Mechanisms in Colorectal Cancer

PURPOSE

The multi-kinase inhibitor (mKi) regorafenib has demonstrated efficacy in chemorefractory patients with metastatic colorectal cancer (mCRC). However, lack of predictive biomarkers and concerns over significant toxicities hamper the use of regorafenib in clinical practice.

EXPERIMENTAL DESIGN

Serial liquid biopsies were obtained at baseline and monthly until disease progression in chemorefractory patients with mCRC treated with regorafenib in a phase II clinical trial (PROSPECT-R n = 40; NCT03010722) and in a multicentric validation cohort (n = 241). Tissue biopsies collected at baseline, after 2 months and at progression in the PROSPECT-R trial were used to establish patient-derived organoids (PDO) and for molecular analyses. MicroRNA profiling was performed on baseline bloods using the NanoString nCounter platform and results were validated by digital-droplet PCR and/or ISH in paired liquid and tissue biopsies. PDOs co-cultures and PDO-xenotransplants were generated for functional analyses.

RESULTS

Large-scale microRNA expression analysis in longitudinal matched liquid and tissue biopsies from the PROSPECT-R trial identified MIR652-3p as a biomarker of clinical benefit to regorafenib. These findings were confirmed in an independent validation cohort and in a "control" group of 100 patients treated with lonsurf. Using ex vivo co-culture assays paired with single-cell RNA-sequencing of PDO established pre- and post-treatment, we modeled regorafenib response observed in vivo and in patients, and showed that MIR652-3p controls resistance to regorafenib by impairing regorafenib-induced lethal autophagy and by orchestrating the switch from neo-angiogenesis to vessel co-option.

CONCLUSIONS

Our results identify MIR652-3p as a potential biomarker and as a driver of cell and non-cell-autonomous mechanisms of resistance to regorafenib.

Role of Hypoxia and Rac1 Inhibition in the Metastatic Cascade

The hypoxic condition has a pivotal role in solid tumors and was shown to correlate with the poor outcome of anticancer treatments. Hypoxia contributes to tumor progression and leads to therapy resistance. Two forms of a hypoxic environment might have relevance in tumor mass formation: chronic and cyclic hypoxia. The main regulators of hypoxia are hypoxia-inducible factors, which regulate the cell survival, proliferation, motility, metabolism, pH, extracellular matrix function, inflammatory cells recruitment and angiogenesis. The metastatic process consists of different steps in which hypoxia-inducible factors can play an important role. Rac1, belonging to small G-proteins, is involved in the metastasis process as one of the key molecules of migration, especially in a hypoxic environment. The effect of hypoxia on the tumor phenotype and the signaling pathways which may interfere with tumor progression are already quite well known. Although the role of Rac1, one of the small G-proteins, in hypoxia remains unclear, predominantly, in vitro studies performed so far confirm that Rac1 inhibition may represent a viable direction for tumor therapy.

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

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

The clinical manifestations and molecular pathogenesis of radiation fibrosis

Advances in radiation techniques have enabled the precise delivery of higher doses of radiotherapy to tumours, while sparing surrounding healthy tissues. Consequently, the incidence of radiation toxicities has declined, and will likely continue to improve as radiotherapy further evolves. Nonetheless, ionizing radiation elicits tissue-specific toxicities that gradually develop into radiation-induced fibrosis, a common long-term side-effect of radiotherapy. Radiation fibrosis is characterized by an aberrant wound repair process, which promotes the deposition of extensive scar tissue, clinically manifesting as a loss of elasticity, tissue thickening, and organ-specific functional consequences. In addition to improving the existing technologies and guidelines directing the administration of radiotherapy, understanding the pathogenesis underlying radiation fibrosis is essential for the success of cancer treatments. This review integrates the principles for radiotherapy dosimetry to minimize off-target effects, the tissue-specific clinical manifestations, the key cellular and molecular drivers of radiation fibrosis, and emerging therapeutic opportunities for both prevention and treatment.

Construction and validation of a hypoxia-related gene signature to predict the prognosis of breast cancer

BACKGROUND

Among the most common forms of cancer worldwide, breast cancer posed a serious threat to women. Recent research revealed a lack of oxygen, known as hypoxia, was crucial in forming breast cancer. This research aimed to create a robust signature with hypoxia-related genes to predict the prognosis of breast cancer patients. The function of hypoxia genes was further studied through cell line experiments.

MATERIALS AND METHODS

In the bioinformatic part, transcriptome and clinical information of breast cancer were obtained from The Cancer Genome Atlas(TCGA). Hypoxia-related genes were downloaded from the Genecards Platform. Differentially expressed hypoxia-related genes (DEHRGs) were identified. The TCGA filtered data was evenly split, ensuring a 1:1 distribution between the training and testing sets. Prognostic-related DEHRGs were identified through Cox regression. The signature was established through the training set. Then, it was validated using the test set and external validation set GSE131769 from Gene Expression Omnibus (GEO). The nomogram was created by incorporating the signature and clinicopathological characteristics. The predictive value of the nomogram was evaluated by C-index and receiver operating characteristiccurve. Immune microenvironment and mutation burden were also examined. In the experiment part, the function of the two most significant hypoxia-related genes were further explored by cell-line experiments.

RESULTS

In the bioinformatic part, 141 up-regulated and 157 down-regulated DEHRGs were screened out. A prognostic signature was constructed containing nine hypoxia genes (ALOX15B, CA9, CD24, CHEK1, FOXM1, HOTAIR, KCNJ11, NEDD9, PSME2) in the training set. Low-risk patients exhibited a much more favorable prognosis than higher-risk ones (P < 0.001). The signature was double-validated in the test set and GSE131769 (P = 0.006 and P = 0.001). The nomogram showed excellent predictive value with 1-year OS AUC: 0.788, 3-year OS AUC: 0.783, and 5-year OS AUC: 0.817. Patients in the high-risk group had a higher tumor mutation burden when compared to the low-risk group. In the experiment part, the down-regulation of PSME2 inhibited cell growth ability and clone formation capability of breast cancer cells, while the down-regulation of KCNJ11 did not have any functions.

CONCLUSION

Based on 9 DEHRGs, a reliable signature was established through the bioinformatic method. It could accurately predict the prognosis of breast cancer patients. Cell line experiment indicated that PSME2 played a protective role. Summarily, we provided a new insight to predict the prognosis of breast cancer by hypoxia-related genes.

Sirtuins in intervertebral disc degeneration: current understanding

BACKGROUND

Intervertebral disc degeneration (IVDD) is one of the etiologic factors of degenerative spinal diseases, which can lead to a variety of pathological spinal conditions such as disc herniation, spinal stenosis, and scoliosis. IVDD is a leading cause of lower back pain, the prevalence of which increases with age. Recently, Sirtuins/SIRTs and their related activators have received attention for their activity in the treatment of IVDD. In this paper, a comprehensive systematic review of the literature on the role of SIRTs and their activators on IVDD in recent years is presented. The molecular pathways involved in the regulation of IVDD by SIRTs are summarized, and the effects of SIRTs on senescence, inflammatory responses, oxidative stress, and mitochondrial dysfunction in myeloid cells are discussed with a view to suggesting possible solutions for the current treatment of IVDD.

PURPOSE

This paper focuses on the molecular mechanisms by which SIRTs and their activators act on IVDD.

METHODS

A literature search was conducted in Pubmed and Web of Science databases over a 13-year period from 2011 to 2024 for the terms "SIRT", "Sirtuin", "IVDD", "IDD", "IVD", "NP", "Intervertebral disc degeneration", "Intervertebral disc" and "Nucleus pulposus".

RESULTS

According to the results, SIRTs and a large number of activators showed positive effects against IVDD.SIRTs modulate autophagy, myeloid apoptosis, oxidative stress and extracellular matrix degradation. In addition, they attenuate inflammatory factor-induced disc damage and maintain homeostasis during disc degeneration. Several clinical studies have reported the protective effects of some SIRTs activators (e.g., resveratrol, melatonin, honokiol, and 1,4-dihydropyridine) against IVDD.

CONCLUSION

The fact that SIRTs and their activators play a hundred different roles in IVDD helps to better understand their potential to develop further treatments for IVDD.

NOVELTY

This review summarizes current information on the mechanisms of action of SIRTs in IVDD and the challenges and limitations of translating their basic research into therapy.

Emerging roles of prominin-1 (CD133) in the dynamics of plasma membrane architecture and cell signaling pathways in health and disease

Prominin-1 (CD133) is a cholesterol-binding membrane glycoprotein selectively associated with highly curved and prominent membrane structures. It is widely recognized as an antigenic marker of stem cells and cancer stem cells and is frequently used to isolate them from biological and clinical samples. Recent progress in understanding various aspects of CD133 biology in different cell types has revealed the involvement of CD133 in the architecture and dynamics of plasma membrane protrusions, such as microvilli and cilia, including the release of extracellular vesicles, as well as in various signaling pathways, which may be regulated in part by posttranslational modifications of CD133 and its interactions with a variety of proteins and lipids. Hence, CD133 appears to be a master regulator of cell signaling as its engagement in PI3K/Akt, Src-FAK, Wnt/β-catenin, TGF-β/Smad and MAPK/ERK pathways may explain its broad action in many cellular processes, including cell proliferation, differentiation, and migration or intercellular communication. Here, we summarize early studies on CD133, as they are essential to grasp its novel features, and describe recent evidence demonstrating that this unique molecule is involved in membrane dynamics and molecular signaling that affects various facets of tissue homeostasis and cancer development. We hope this review will provide an informative resource for future efforts to elucidate the details of CD133's molecular function in health and disease.

Dynamic, IPSC-derived hepatic tissue tri-culture system for the evaluation of liver physiologyin vitro

Availability of hepatic tissue for the investigation of metabolic processes is severely limited. While primary hepatocytes or animal models are widely used in pharmacological applications, a change in methodology towards more sustainable and ethical assays is highly desirable. Stem cell derived hepatic cells are generally regarded as a viable alternative for the above model systems, if current limitations in functionality and maturation can be overcome. By combining microfluidic organ-on-a-chip technology with individually differentiated, multicellular hepatic tissue fractions, we aim to improve overall functionality of hepatocyte-like cells, as well as evaluate cellular composition and interactions with non-parenchymal cell populations towards the formation of mature liver tissue. Utilizing a multi-omic approach, we show the improved maturation profiles of hepatocyte-like cells maintained in a dynamic microenvironment compared to standard tissue culture setups without continuous perfusion. In order to evaluate the resulting tissue, we employ single cell sequencing to distinguish formed subpopulations and spatial localization. While cellular input was strictly defined based on established differentiation protocols of parenchyma, endothelial and stellate cell fractions, resulting hepatic tissue was shown to comprise a complex mixture of epithelial and non-parenchymal fractions with specific local enrichment of phenotypes along the microchannel. Following this approach, we show the importance of passive, paracrine developmental processes in tissue formation. Using such complex tissue models is a crucial first step to develop stem cell-derivedin vitrosystems that can compare functionally with currently used pharmacological and toxicological applications.

Recent advances in the potential effects of natural products from traditional Chinese medicine against respiratory diseases targeting ferroptosis

Respiratory diseases, marked by structural changes in the airways and lung tissues, can lead to reduced respiratory function and, in severe cases, respiratory failure. The side effects of current treatments, such as hormone therapy, drugs, and radiotherapy, highlight the need for new therapeutic strategies. Traditional Chinese Medicine (TCM) offers a promising alternative, leveraging its ability to target multiple pathways and mechanisms. Active compounds from Chinese herbs and other natural sources exhibit anti-inflammatory, antioxidant, antitumor, and immunomodulatory effects, making them valuable in preventing and treating respiratory conditions. Ferroptosis, a unique form of programmed cell death (PCD) distinct from apoptosis, necrosis, and others, has emerged as a key area of interest. However, comprehensive reviews on how natural products influence ferroptosis in respiratory diseases are lacking. This review will explore the therapeutic potential and mechanisms of natural products from TCM in modulating ferroptosis for respiratory diseases like acute lung injury (ALI), asthma, pulmonary fibrosis (PF), chronic obstructive pulmonary disease (COPD), lung ischemia-reperfusion injury (LIRI), pulmonary hypertension (PH), and lung cancer, aiming to provide new insights for research and clinical application in TCM for respiratory health.

Hypoxia and low-glucose environments co-induced HGDILnc1 promote glycolysis and angiogenesis

Small bowel vascular malformation disease (SBVM) commonly causes obscure gastrointestinal bleeding (OGIB). However, the pathogenetic mechanism and the role of lncRNAs in SBVM remain largely unknown. Here, we found that hypoxia and low-glucose environments co-augment angiogenesis and existed in SBVM. Mechanistically, hypoxia and low-glucose environments supported angiogenesis via activation of hypoxia and glucose deprivation-induced lncRNA (HGDILnc1) transcription by increasing binding of the NeuroD1 transcription factor to the HGDILnc1 promoter. Raised HGDILnc1 acted as a suppressor of α-Enolase 1 (ENO1) small ubiquitin-like modifier modification (SUMOylation)-triggered ubiquitination, and an activator of transcription of Aldolase C (ALDOC) via upregulation of Histone H2B lysine 16 acetylation (H2BK16ac) level in the promoter of ALDOC, and consequently promoting glycolysis and angiogenesis. Moreover, HGDILnc1 was clinically positively correlated with Neurogenic differentiation 1 (NeuroD1), ENO1, and ALDOC in SBVM tissues, and could function as a biomarker for SBVM diagnosis and therapy. These findings suggest that hypoxia and low-glucose environments were present in SBVM tissues, and co-augmented angiogenesis. Hypoxia and low-glucose environments co-induced HGDILnc1, which is higher expressed in SBVM tissue compared with normal tissue, could promoted glycolysis and angiogenesis.

Detecting subtle transcriptomic perturbations induced by lncRNAs knock-down in single-cell CRISPRi screening using a new sparse supervised autoencoder neural network

Single-cell CRISPR-based transcriptome screens are potent genetic tools for concomitantly assessing the expression profiles of cells targeted by a set of guides RNA (gRNA), and inferring target gene functions from the observed perturbations. However, due to various limitations, this approach lacks sensitivity in detecting weak perturbations and is essentially reliable when studying master regulators such as transcription factors. To overcome the challenge of detecting subtle gRNA induced transcriptomic perturbations and classifying the most responsive cells, we developed a new supervised autoencoder neural network method. Our Sparse supervised autoencoder (SSAE) neural network provides selection of both relevant features (genes) and actual perturbed cells. We applied this method on an in-house single-cell CRISPR-interference-based (CRISPRi) transcriptome screening (CROP-Seq) focusing on a subset of long non-coding RNAs (lncRNAs) regulated by hypoxia, a condition that promote tumor aggressiveness and drug resistance, in the context of lung adenocarcinoma (LUAD). The CROP-seq library of validated gRNA against a subset of lncRNAs and, as positive controls, HIF1A and HIF2A, the 2 main transcription factors of the hypoxic response, was transduced in A549 LUAD cells cultured in normoxia or exposed to hypoxic conditions during 3, 6 or 24 h. We first validated the SSAE approach on HIF1A and HIF2 by confirming the specific effect of their knock-down during the temporal switch of the hypoxic response. Next, the SSAE method was able to detect stable short hypoxia-dependent transcriptomic signatures induced by the knock-down of some lncRNAs candidates, outperforming previously published machine learning approaches. This proof of concept demonstrates the relevance of the SSAE approach for deciphering weak perturbations in single-cell transcriptomic data readout as part of CRISPR-based screening.

Targeting hypoxia-inducible factors: therapeutic opportunities and challenges

Hypoxia-inducible factors (HIFs) are highly conserved transcription factors that are crucial for adaptation of metazoans to limited oxygen availability. Recently, HIF activation and inhibition have emerged as therapeutic targets in various human diseases. Pharmacologically desirable effects of HIF activation include erythropoiesis stimulation, cellular metabolism optimization during hypoxia and adaptive responses during ischaemia and inflammation. By contrast, HIF inhibition has been explored as a therapy for various cancers, retinal neovascularization and pulmonary hypertension. This Review discusses the biochemical mechanisms that control HIF stabilization and the molecular strategies that can be exploited pharmacologically to activate or inhibit HIFs. In addition, we examine medical conditions that benefit from targeting HIFs, the potential side effects of HIF activation or inhibition and future challenges in this field.

The Effect of High-Altitude Hypoxia on Neuropsychiatric Functions

Liu, Bo, Minlan Yuan, Mei Yang, Hongru Zhu, and Wei Zhang. The effect of high-altitude hypoxia on neuropsychiatric functions. High Alt Med Biol. 25:26-41, 2024. Background: In recent years, there has been a growing popularity in engaging in activities at high altitudes, such as hiking and work. However, these high-altitude environments pose risks of hypoxia, which can lead to various acute or chronic cerebral diseases. These conditions include common neurological diseases such as acute mountain sickness (AMS), high-altitude cerebral edema, and altitude-related cerebrovascular diseases, as well as psychiatric disorders such as anxiety, depression, and psychosis. However, reviews of altitude-related neuropsychiatric conditions and their potential mechanisms are rare. Methods: We conducted searches on PubMed and Google Scholar, exploring existing literature encompassing preclinical and clinical studies. Our aim was to summarize the prevalent neuropsychiatric diseases induced by altitude hypoxia, the potential pathophysiological mechanisms, as well as the available pharmacological and nonpharmacological strategies for prevention and intervention. Results: The development of altitude-related cerebral diseases may arise from various pathogenic processes, including neurovascular alterations associated with hypoxia, cytotoxic responses, activation of reactive oxygen species, and dysregulation of the expression of hypoxia inducible factor-1 and nuclear factor erythroid 2-related factor 2. Furthermore, the interplay between hypoxia-induced neurological and psychiatric changes is believed to play a role in the progression of brain damage. Conclusions: While there is some evidence pointing to pathophysiological changes in hypoxia-induced brain damage, the precise mechanisms responsible for neuropsychiatric alterations remain elusive. Currently, the range of prevention and intervention strategies available is primarily focused on addressing AMS, with a preference for prevention rather than treatment.

Signaling Pathways Triggering Therapeutic Hydrogels in Promoting Chronic Wound Healing

In recent years, there has been a significant increase in the prevalence of chronic wounds, such as pressure ulcers, diabetic foot ulcers, and venous ulcers of the lower extremities. The main contributors to chronic wound formation are bacterial infection, prolonged inflammation, and peripheral vascular disease. However, effectively treating these chronic wounds remains a global challenge. Hydrogels have extensively explored as wound healing dressing because of their excellent biocompatibility and structural similarity to extracellular matrix (ECM). Nonetheless, much is still unknown how the hydrogels promote wound repair and regeneration. Signaling pathways play critical roles in wound healing process by controlling and coordinating cells and biomolecules. Hydrogels, along with their therapeutic ingredients that impact signaling pathways, have the potential to significantly enhance the wound healing process and its ultimate outcomes. Understanding this interaction will undoubtedly provide new insights into developing advanced hydrogels for wound repair and regeneration. This paper reviews the latest studies on classical signaling pathways and potential targets influenced by hydrogel scaffolds in chronic wound healing. This work hopes that it will offer a different perspective in developing more efficient hydrogels for treating chronic wounds.

The role of oxygen tension in cell fate and regenerative medicine: implications of hypoxia/hyperoxia and free radicals

Oxygen pressure plays an integral role in regulating various aspects of cellular biology. Cell metabolism, proliferation, morphology, senescence, metastasis, and angiogenesis are some instances that are affected by different tensions of oxygen. Hyperoxia or high oxygen concentration, enforces the production of reactive oxygen species (ROS) that disturbs physiological homeostasis, and consequently, in the absence of antioxidants, cells and tissues are directed to an undesired fate. On the other side, hypoxia or low oxygen concentration, impacts cell metabolism and fate strongly through inducing changes in the expression level of specific genes. Thus, understanding the precise mechanism and the extent of the implication of oxygen tension and ROS in biological events is crucial to maintaining the desired cell and tissue function for application in regenerative medicine strategies. Herein, a comprehensive literature review has been performed to find out the impacts of oxygen tensions on the various behaviors of cells or tissues.

Expression and clinical significance of hypoxia-induced long non-coding RNA TCONS_I2_00001955 in breast cancer

BACKGROUND

Long non-coding RNAs (lncRNAs) have been found to play important roles in occurrence, development, and metastasis of various tumors. We aimed to screen long non-coding RNAs (lncRNAs) that promote invasion and metastasis of breast cancer cells under hypoxia, and investigate the relationship between lncRNA expression and clinicopathological features and prognosis in invasive breast cancer.

METHODS

LncRNA microarray was used to screen the differentially expressed lncRNAs in MCF7, MDA-MB-231, and SKBR3 breast cancer cell lines cultured under normoxia and hypoxia, respectively. Quantitative reverse transcription-polymerase chain reaction (qRT-PCR) was used to verify the microarray results. CCK8 and Transwell experiments were performed to identify the lncRNA that promote proliferation, migration, and invasion of breast cancer cells. Expression of the lncRNA and HIF-1α in invasive breast cancer was detected by RNAscope and immunohistochemistry, respectively. Correlation between the lncRNA expression and baseline characteristics was analyzed. Prognostic value of the lncRNA was evaluated using univariate and multivariate Cox regression.

RESULTS

Expression of lncRNA TCONS_I2_00001955 in all the three breast cancer cells was increased under hypoxia. Overexpression of TCONS_I2_00001955 significantly enhanced proliferation, migration, and invasion of SKBR3 cells. Positive expression of TCONS_I2_00001955 was associated with recurrence, metastasis, and high expression of HIF-1α (P < 0.05), and it was an independent risk factor for poor disease-free survival of breast cancer.

CONCLUSION

Hypoxia-induced lncRNA TCONS_I2_00001955 was associated with aggressive feature and poor prognosis of breast cancer.

Acetyl-CoA synthetase 2 contributes to a better prognosis for liver cancer by switching acetate-glucose metabolism

Acetyl-CoA synthetase 2 (ACSS2)-dependent acetate usage has generally been associated with tumorigenesis and increased malignancy in cancers under nutrient-depleted conditions. However, the nutrient usage and metabolic characteristics of the liver differ from those of other organs; therefore, the mechanism of ACSS2-mediated acetate metabolism may also differ in liver cancer. To elucidate the underlying mechanisms of ACSS2 in liver cancer and acetate metabolism, the relationships between patient acetate uptake and metabolic characteristics and between ACSS2 and tumor malignancies were comprehensively studied in vitro, in vivo and in humans. Clinically, we initially found that ACSS2 expression was decreased in liver cancer patients. Moreover, PET-CT imaging confirmed that lower-grade cancer cells take up more 11C-acetate but less 18F-fluorodeoxyglucose (18F-FDG); however, this trend was reversed in higher-grade cancer. Among liver cancer cells, those with high ACSS2 expression avidly absorbed acetate even in a glucose-sufficient environment, whereas those with low ACSS2 expression did not, thereby showing correlations with their respective ACSS2 expression. Metabolomic isotope tracing in vitro and in vivo revealed greater acetate incorporation, greater lipid anabolic metabolism, and less malignancy in high-ACSS2 tumors. Notably, ACSS2 downregulation in liver cancer cells was associated with increased tumor occurrence in vivo. In human patient cohorts, patients in the low-ACSS2 subgroup exhibited reduced anabolism, increased glycolysis/hypoxia, and poorer prognosis. We demonstrated that acetate uptake by ACSS2 in liver cancer is independent of glucose depletion and contributes to lipid anabolic metabolism and reduced malignancy, thereby leading to a better prognosis for liver cancer patients.

The HIF transcription network exerts innate antiviral activity in neurons and limits brain inflammation

Pattern recognition receptors (PRRs) induce host defense but can also induce exacerbated inflammatory responses. This raises the question of whether other mechanisms are also involved in early host defense. Using transcriptome analysis of disrupted transcripts in herpes simplex virus (HSV)-infected cells, we find that HSV infection disrupts the hypoxia-inducible factor (HIF) transcription network in neurons and epithelial cells. Importantly, HIF activation leads to control of HSV replication. Mechanistically, HIF activation induces autophagy, which is essential for antiviral activity. HSV-2 infection in vivo leads to hypoxia in CNS neurons, and mice with neuron-specific HIF1/2α deficiency exhibit elevated viral load and augmented PRR signaling and inflammatory gene expression in the CNS after HSV-2 infection. Data from human stem cell-derived neuron and microglia cultures show that HIF also exerts antiviral and inflammation-restricting activity in human CNS cells. Collectively, the HIF transcription factor system senses virus-induced hypoxic stress to induce cell-intrinsic antiviral responses and limit inflammation.

TFRC, associated with hypoxia and immune, is a prognostic factor and potential therapeutic target for bladder cancer

BACKGROUND

Bladder cancer is a common malignancy of the urinary system, and the survival rate and recurrence rate of patients with muscular aggressive (MIBC) bladder cancer are not ideal. Hypoxia is a pathological process in which cells acquire special characteristics to adapt to anoxic environment, which can directly affect the proliferation, invasion and immune response of bladder cancer cells. Understanding the exact effects of hypoxia and immune-related genes in BLCA is helpful for early assessment of the prognosis of BLCA. However, the prognostic model of BLCA based on hypoxia and immune-related genes has not been reported.

PURPOSE

Hypoxia and immune cell have important role in the prognosis of bladder cancer (BLCA). The aim of this study was to investigate whether hypoxia and immune related genes could be a novel tools to predict the overall survival and immunotherapy of BLCA patients.

METHODS

First, we downloaded transcriptomic data and clinical information of BLCA patients from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) databases. A combined hypoxia and immune signature was then constructed on the basis of the training cohort via least absolute shrinkage and selection operator (LASSO) analysis and validated in test cohort. Afterwards, Kaplan-Meier curves, univariate and multivariate Cox and subgroup analysis were employed to assess the accuracy of our signature. Immune cell infiltration, checkpoint and the Tumor Immune Dysfunction and Exclusion (TIDE) algorithm were used to investigate the immune environment and immunotherapy of BLCA patients. Furthermore, we confirmed the role of TFRC in bladder cancer cell lines T24 and UMUC-3 through cell experiments.

RESULTS

A combined hypoxia and immune signature containing 8 genes were successfully established. High-risk group in both training and test cohorts had significantly poorer OS than low-risk group. Univariate and multivariate Cox analysis indicated our signature could be regarded as an independent prognostic factor. Different checkpoint was differently expressed between two groups, including CTLA4, HAVCR2, LAG3, PD-L1 and PDCD1. TIDE analysis indicated high-risk patients had poor response to immunotherapy and easier to have immune escape. The drug sensitivity analysis showed that high-risk group patients were more potentially sensitive to many drugs. Meanwhile, TFRC could inhibit the proliferation and invasion ability of T24 and UMUC-3 cells.

CONCLUSION

A combined hypoxia and immune-related gene could be a novel predictive model for OS and immunotherapy estimation of BLCA patients and TFRC could be used as a potential therapeutic target in the future.

Diphenyl Diselenide Attenuates Mitochondrial Damage During Initial Hypoxia and Enhances Resistance to Recurrent Hypoxia

Hypoxia plays a significant role in the development of various cerebral diseases, many of which are associated with the potential risk of recurrence due to mitochondrial damage. Conventional drug treatments are not always effective for hypoxia-related brain diseases, necessitating the exploration of alternative compounds. In this study, we investigated the potential of diphenyl diselenide [(PhSe)2] to ameliorate locomotor impairments and mitigate brain mitochondrial dysfunction in zebrafish subjected to hypoxia. Additionally, we explored whether these improvements could confer resistance to recurrent hypoxia. Through a screening process, an appropriate dose of (PhSe)2 was determined, and animals exposed to hypoxia received a single intraperitoneal injection of 100 mg/kg of the compound or vehicle. After 1 h from the injection, evaluations were conducted on locomotor deficits, (PhSe)2 content, mitochondrial electron transport system, and mitochondrial viability in the brain. The animals were subsequently exposed to recurrent hypoxia to assess the latency time to hypoxia symptoms. The findings revealed that (PhSe)2 effectively crossed the blood-brain barrier, attenuated locomotor deficits induced by hypoxia, and improved brain mitochondrial respiration by modulating complex III. Furthermore, it enhanced mitochondrial viability in the telencephalon, contributing to greater resistance to recurrent hypoxia. These results demonstrate the beneficial effects of (PhSe)2 on both hypoxia and recurrent hypoxia, with cerebral mitochondria being a critical target of its action. Considering the involvement of brain hypoxia in numerous pathologies, (PhSe)2 should be further tested to determine its effectiveness as a potential treatment for hypoxia-related brain diseases.

Male histone deacetylase 6 (HDAC6) knockout mice have enhanced ventilatory responses to hypoxic challenge

Histone deacetylase 6 (HDAC6) is a class II histone deacetylase that is predominantly localized in the cytoplasm of cells. HDAC6 associates with microtubules and regulates acetylation of tubulin and other proteins. The possibility that HDAC6 participates in hypoxic signaling is supported by evidence that 1) hypoxic gas challenges cause microtubule depolymerization, 2) expression of hypoxia inducible factor alpha (HIF-1α) is regulated by microtubule alterations in response to hypoxia, and 3) inhibition of HDAC6 prevents HIF-1α expression and protects tissue from hypoxic/ischemic insults. The aim of this study was to address whether the absence of HDAC6 alters ventilatory responses during and/or after hypoxic gas challenge (10% O2, 90% N2 for 15 min) in adult male wildtype (WT) C57BL/6 mice and HDAC6 knock-out (KO) mice. Key findings were that 1) baseline values for frequency of breathing, tidal volume, inspiratory and expiratory times, and end expiratory pause were different between knock-out mice and wildtype mice, 2) ventilatory responses during hypoxic challenge were more robust in KO mice than WT mice for recorded parameters including, frequency of breathing, minute ventilation, inspiratory and expiratory durations, peak inspiratory and expiratory flows, and inspiratory and expiratory drives, and 3) responses upon return to room-air were markedly different in KO compared to WT mice for frequency of breathing, minute ventilation, inspiratory and expiratory durations, end expiratory pause (but not end inspiratory pause), peak inspiratory and expiratory flows, and inspiratory and expiratory drives. These data suggest that HDAC6 may have a fundamentally important role in regulating the hypoxic ventilatory response in mice.

The involvement of RNA N6-methyladenosine and histone methylation modification in decidualization and endometriosis-associated infertility

Defective decidualization of endometrial stromal cells (ESCs) in endometriosis (EM) patients leads to inadequate endometrial receptivity and EM-associated infertility. Hypoxia is an inevitable pathological process of EM and participates in deficient decidualization of the eutopic secretory endometrium. Enhancer of zeste homology 2 (EZH2) is a methyltransferase which catalyses H3K27Me3, leading to decreased expression levels of target genes. Although EZH2 expression is low under normal decidualization, it is abundantly increased in the eutopic secretory endometrium of EM and is induced by hypoxia. Chromatin immunoprecipitation-PCR results revealed that decidua marker IGFBP1 is a direct target of EZH2, partially explaining the increased levels of histone methylation modification in defected decidualization of EM. To mechanism controlling this, we examined the effects of hypoxia on EZH2 and decidualization. EZH2 mRNA showed decreased m6 A modification and increased expression levels under hypoxia and decidualization combined treatment. Increased EZH2 expression was due to the increased expression of m6 A demethylase ALKBH5 and decreased expression of the m6 A reader protein YTHDF2. YTHDF2 directly bind to the m6 A modification site of EZH2 to promote EZH2 mRNA degradation in ESCs. Moreover, selective Ezh2 depletion in mouse ESCs increased endometrial receptivity and improved mouse fertility by up-regulating decidua marker IGFBP1 expression. This is the first report showing that YTHDF2 can act as a m6 A reader to promote decidualization by decreasing the stability of EZH2 mRNA and further increasing the expression of IGFBP1 in ESCs. Taken together, our findings highlight the critical role of EZH2/H3K27Me3 in decidualization and reveal a novel epigenetic mechanism by which hypoxia can suppress EM decidualization by decreasing the m6 A modification of EZH2 mRNA.

Characterization of hypoxia-responsive states in ovarian cancer to identify hot tumors and aid adjuvant therapy

BACKGROUNDS

The hypoxia-responsive state of cancer is a complex pathophysiological process involving numerous genes playing different roles. Due to the rapid proliferation of cancer cells and chaotic angiogenesis, the clinical features of hypoxia-responsive states are not yet clear in patients with ovarian cancer.

METHODS

Based on the RNA expression levels of 14 hypoxic markers, our study screened out hypoxia-related genes and construct a hypoxic score pattern to quantify the hypoxia-responsive states of a single tumor. Combining clinical prognosis, tumor mutation burden, microsatellite instability, the expression level of the immune checkpoint, IC50, and other indicators to evaluate the impact of different hypoxia-responsive states on clinical prognosis and therapeutic sensitivity.

RESULTS

Our study identified a subgroup with an active hypoxia-responsive state and they have a worse clinical prognosis but exhibit higher immunogenicity and higher sensitivity to immunotherapy.

CONCLUSIONS

This work revealed that hypoxia-responsive states played an important role in formation of tumor immunogenicity. Evaluating the hypoxia-responsive state will contribute to guiding more effective immunotherapy strategies.

HIF-1α/METTL1/m7G axis is involved in CRC response to hypoxia

BACKGROUND

In recent years, many studies have confirmed that hypoxia and hypoxia inducible factor (HIF)-1α drive the development of colorectal cancer (CRC). HIF-1α also modulates epitranscriptomic remodeling to regulate cancer development. However, the mechanism by which RNA methylation is altered under hypoxic conditions and the underlying regulatory mechanisms in CRC remain unclear.

METHODS

Here, seven common types of modifications of mRNA and tRNA were quantitated using liquid chromatography-tandem mass spectrometry. To validate the robustness of the profiling data, modifications that were consistently altered across the three CRC cell lines under hypoxia were validated via dot blot analysis. Then, 10 enzymes that could regulate the abundance of three RNA modifications in tRNA were measured in CRC cells after hypoxia treatment using quantitative real-time polymerase chain reaction. Furthermore, the regulatory role of HIF-1α in the expression of methyltransferase 1 (METTL1) under hypoxic conditions was confirmed using METTL1 promoter activity assays and HIF-1α small interfering RNA (siRNA). The binding capacity of HIF-1α to each hypoxia response element (HRE) in the promoter of METTL1 was investigated by performing Chromatin immunoprecipitation assay (ChIP).

RESULTS

Abundance of RNA modifications was altered more consistently and significantly in tRNA than in mRNA under hypoxic conditions. In addition, the abundance of N7-methyleguanosine (m7G) modification in tRNA decreased significantly under hypoxic conditions. As a methyltransferase of the m7G modification in tRNA, the expression of METTL1 mRNA was drastically downregulated under hypoxic conditions. Mechanistically, suppression of HIF-1α by siRNA upregulated the METTL1 promoter activity. Furthermore, ChIP showed that HIF-1α could bind with an HRE in the promoter region of METTL1, indicating that METTL1 is a direct target of HIF-1α in CRC cells under hypoxic conditions.

CONCLUSIONS

Our study revealed that the abundance of the m7G modification in tRNA was drastically reduced in CRC cells dependent on the HIF-1α-mediated inhibition of METTL1 transcription under hypoxic conditions.

The regulation of plasma gelsolin by DNA methylation in ovarian cancer chemo-resistance

BACKGROUND

Ovarian cancer (OVCA) is the most lethal gynecologic cancer and chemoresistance remains a major hurdle to successful therapy and survival of OVCA patients. Plasma gelsolin (pGSN) is highly expressed in chemoresistant OVCA compared with their chemosensitive counterparts, although the mechanism underlying the differential expression is not known. Also, its overexpression significantly correlates with shortened survival of OVCA patients. In this study, we investigated the methylation role of Ten eleven translocation isoform-1 (TET1) in the regulation of differential pGSN expression and chemosensitivity in OVCA cells.

METHODS

Chemosensitive and resistant OVCA cell lines of different histological subtypes were used in this study to measure pGSN and TET1 mRNA abundance (qPCR) as well as protein contents (Western blotting). To investigate the role of DNA methylation specifically in pGSN regulation and pGSN-induced chemoresistance, DNMTs and TETs were pharmacologically inhibited in sensitive and resistant OVCA cells using specific inhibitors. DNA methylation was quantified using EpiTYPER MassARRAY system. Gain-and-loss-of-function assays were used to investigate the relationship between TET1 and pGSN in OVCA chemoresponsiveness.

RESULTS

We observed differential protein and mRNA expressions of pGSN and TET1 between sensitive and resistant OVCA cells and cisplatin reduced their expression in sensitive but not in resistant cells. We observed hypomethylation at pGSN promoter upstream region in resistant cells compared to sensitive cells. Pharmacological inhibition of DNMTs increased pGSN protein levels in sensitive OVCA cells and decreased their responsiveness to cisplatin, however we did not observe any difference in methylation level at pGSN promoter region. TETs inhibition resulted in hypermethylation at multiple CpG sites and decreased pGSN protein level in resistant OVCA cells which was also associated with enhanced response to cisplatin, findings that suggested the methylation role of TETs in the regulation of pGSN expression in OVCA cells. Further, we found that TET1 is inversely related to pGSN but positively related to chemoresponsiveness of OVCA cells.

CONCLUSION

Our findings broaden our knowledge about the epigenetic regulation of pGSN in OVCA chemoresistance and reveal a novel potential target to re-sensitize resistant OVCA cells. This may provide a future therapeutic strategy to improve the overall OVCA patient survival.

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

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

Perfluorocarbon Nanoparticles Incorporating Ginkgolide B: Artificial O2 Carriers with Antioxidant Activity and Antithrombotic Effect

Ischemic stroke primarily leads to insufficient oxygen delivery in ischemic area. Prompt reperfusion treatment for restoration of oxygen is clinically suggested but mediates more surging reactive oxygen species (ROS) generation and oxidative damage, known as ischemia-reperfusion injury (IRI). Therefore, the regulation of oxygen content is a critical point to prevent cerebral ischemia induced pathological responses and simultaneously alleviate IRI triggered by the sudden oxygen restoration. In this work, we constructed a perfluorocarbon (PFC)-based artificial oxygen nanocarrier (PFTBA-L@GB), using an ultrasound-assisted emulsification method, alleviates the intracerebral hypoxic state in ischemia stage and IRI after reperfusion. The high oxygen solubility of PFC allows high oxygen efficacy. Furthermore, PFC has the adhesion affinity to platelets and prevents the overactivation of platelet. The encapsulated payload, ginkgolide B (GB) exerts its anti-thrombosis by antagonism on platelet activating factor and antioxidant effect by upregulation of antioxidant molecular pathway. The versatility of the present strategy provides a practical approach to build a simple, safe, and relatively effective oxygen delivery agent to alleviate hypoxia, promote intracerebral oxygenation, anti-inflammatory, reduce intracerebral oxidative stress damage and thrombosis and caused by stroke.

Prognostic value of hypoxia-responsive gene expression profile in patients diagnosed with head and neck squamous cell carcinoma

Head and neck squamous cell carcinoma (HNSCC) is a disease associated with a severe mortality and high risk of distant metastasis and local recurrence. Currently, surgery and radiotherapy are the main treatment modes, however, therapeutic efficacy of radiotherapy is linked to tumor resistance. Hypoxia has been shown to affect outcome of radiotherapy in HNSCC patients. The aim of this study was to verify the expression of the previously identified hypoxia-responsive genes (CA9, CASP14, LOX, GLUT3, SERPINE1, AREG, EREG, CCNB1 and KIF14) in HNSCC patient material as well as assess their prognostic potential. Tumor biopsies obtained before start of radiotherapy from 32 HNSCC patients classified as responders or non-responders were investigated in this study. The mRNA expression was quantified using RT-qPCR. The mRNA expression of CA9, SERPINE1 and KIF14 was significantly higher in the analyzed patient material compared with the non-cancerous oral tissue. Moreover, the KIF14 mRNA expression was significantly higher in the responder group compared to non-responders. Further studies demonstrated that knockdown of KIF14 reverses its radiosensitizing capability. Additionally, low expression of KIF14 mRNA correlated with significantly shorter OS (overall survival). In conclusion, our results suggest that KIF14 might be a useful prognostic and predictive marker in HNSCC.

Hypoxia Induces Tumor-Derived Exosome SNHG16 to Mediate Nasopharyngeal Carcinoma Progression through the miR-23b-5p/MCM6 Pathway

This study aims to investigate the mechanism of tumor-derived exosomal (EVs) SNHG16 in promoting the progression of nasopharyngeal carcinoma (NPC). QRT-PCR was used to detect the expression of SNHG16, miR-23b-5p and MCM6 in NPC. MTT, flow cytometry and transwell were used to detect the effects of them on the proliferation, cycle, apoptosis and invasion ability of NPC. Transmission electron microscopy, Western blotting and BCA were used to verify the regulation of exosome secretion under different oxygen environments. Our results showed that hypoxia induces tumor-derived exosome SNHG16 to mediate NPC progression through the miR-23b-5p/MCM6 pathway.

Hypoxia and Hypoxia Mimetic Agents As Potential Priming Approaches to Empower Mesenchymal Stem Cells

Mesenchymal stem cells (MSC) exhibit self-renewal capacity and multilineage differentiation potential, making them attractive for research and clinical application. The properties of MSC can vary depending on specific micro-environmental factors. MSC resides in specific niches with low oxygen concentrations, where oxygen functions as a metabolic substrate and a signaling molecule. Conventional physical incubators or chemically hypoxia mimetic agents are applied in cultures to mimic the original low oxygen tension settings where MSC originated. This review aims to focus on the current knowledge of the effects of various physical hypoxic conditions and widely used hypoxia-mimetic agents-PHD inhibitors on mesenchymal stem cells at a cellular and molecular level, including proliferation, stemness, differentiation, viability, apoptosis, senescence, migration, immunomodulation behaviors, as well as epigenetic changes.

Identification of hypoxia-related gene signatures based on multi-omics analysis in lung adenocarcinoma

Lung adenocarcinoma (LUAD) is the most common type of lung cancer and one of the malignancies with the highest incidence rate and mortality worldwide. Hypoxia is a typical feature of tumour microenvironment (TME), which affects the progression of LUAD from multiple molecular levels. However, the underlying molecular mechanisms behind LUAD hypoxia are not fully understood. In this study, we estimated the level of hypoxia by calculating a score based on 15 hypoxia genes. The hypoxia scores were relatively high in LUAD patients with poor prognosis and were bound up with tumour node metastasis (TNM) stage, tumour size, lymph node, age and gender. By comparison of high hypoxia score group and low hypoxia score group, 1820 differentially expressed genes were identified, among which up-regulated genes were mainly about cell division and proliferation while down-regulated genes were primarily involved in cilium-related biological processes. Besides, LUAD patients with high hypoxia scores had higher frequencies of gene mutations, among which TP53, TTN and MUC16 had the highest mutation rates. As for DNA methylation, 1015 differentially methylated probes-related genes were found and may play potential roles in tumour-related neurobiological processes and cell signal transduction. Finally, a prognostic model with 25 multi-omics features was constructed and showed good predictive performance. The area under curve (AUC) values of 1-, 3- and 5-year survival reached 0.863, 0.826 and 0.846, respectively. Above all, our findings are helpful in understanding the impact and molecular mechanisms of hypoxia in LUAD.

Effect and mechanism of hypoxia on differentiation of porcine-induced pluripotent stem cells into vascular endothelial cells

Pigs are similar to humans in organ size and physiological function, and are considered as good models for studying cardiovascular diseases. The study of porcine-induced pluripotent stem cells (piPSC) differentiating into vascular endothelial cells (EC) is expected to open up a new way of obtaining high-quality seed cells. Given that the hypoxic environment has an important role in the differentiation process of vascular EC, this work intends to establish a hypoxia-induced differentiation system of piPSC into vascular EC. There is evidence that the hypoxia microenvironment in the initial stage could significantly improve differentiation efficiency. Further study suggests that the hypoxia culture system supports a combined effect of hypoxia inducible factors and their associated regulatory molecules, such as HIF-1α, VEGFA, FGF2, LDH-A, and PDK1, which can efficiently promote the lineage-specific differentiation of piPSC into EC. Most notably, the high level of ETV2 after 4 d of hypoxic treatment indicates that it possibly plays an important role in the promoting process of EC differentiation. The research is expected to help the establishment of new platforms for piPSC directional induction research, so as to obtain adequate seed cells with ideal phenotype and functionality.

Deciphering the Mechanism of Siwu Decoction Inhibiting Liver Metastasis by Integrating Network Pharmacology and In Vivo Experimental Validation

BACKGROUND

Siwu Decoction (SWD) is a well-known classical TCM formula that has been shown to be effective as a basis for preventing and reducing liver metastases (LM). However, the active ingredients and potential molecular mechanisms remain unclear.

OBJECTIVE

This study aimed to systematically analyze the active ingredients and potential molecular mechanisms of SWD on LM and validate mechanisms involved.

MATERIALS AND METHODS

The active ingredients in SWD were extracted by UHPLC-MS/MS in a latest study. Protox II was retrieved to obtain toxicological parameters to detect safety. Swiss Target Prediction database was exploited to harvest SWD targets. Five databases, Gene Cards, DisGeNET, Drugbank, OMIM, and TTD, were employed to filter pathogenic targets of LM. STRING database was utilized to construct the protein-protein interaction network for therapeutic targets, followed by Gene Ontology and the Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis. GEPIA database and the Human Protein Atlas were taken to observe the expression of core genes and proteins. ImmuCellAI algorithm was applied to analyze the immune microenvironment and survival relevant to core genes. Molecular docking was performed to verify the affinity of SWD effective ingredients to core targets. In vivo experiments were carried out to validate the anti-LM efficacy of SWD and verify the pivotal mechanisms of action.

RESULTS

Eighteen main bioactive phytochemicals identified were all non-hepatotoxic. PPI network acquired 118 therapeutic targets, of which VEGFA, CASP3, STAT3, etc. were identified as core targets. KEGG analysis revealed that HIF-1 pathway and others were critical. After tandem targets and pathways, HIF-1/VEGF was regarded as the greatest potential pathway. VEGFA and HIF-1 were expressed differently in various stages of cancer and normal tissues. There was a negative regulation of immunoreactive cells by VEGFA, which was influential for prognosis. Molecular docking confirmed the tight binding to VEGFA. This study revealed the exact effect of SWD against LM, and identified significant inhibition the expression of HIF-1α, VEGF, and CD31 in the liver microenvironment.

CONCLUSION

This study clarified the active ingredients of SWD, the therapeutic targets of LM and potential molecular mechanisms. SWD may protect against LM through suppressing HIF-1/VEGF pathway.

Hypoxia-Responsive Golgi-Targeted Prodrug Assembled with Anthracycline for Improved Antitumor and Antimetastasis Efficacy

Tumor metastasis is an intricate multistep process regulated via various proteins and enzymes modified and secreted by swollen Golgi apparatus in tumor cells. Thus, Golgi complex is considered as an important target for the remedy of metastasis. Currently, Golgi targeting technologies are mostly employed in Golgi-specific fluorescent probes for diagnosis, but their applications in therapy are rarely reported. Herein, we proposed a prodrug (INR) that can target and destroy the Golgi apparatus, which consisted of indomethacin (IMC) as the Golgi targeting moiety and retinoic acid (RA), a Golgi disrupting agent. The linker between IMC and RA was designed as a hypoxia-responsive nitroaromatic structure, which ensured the release of the prototype drugs in the hypoxic tumor microenvironment. Furthermore, INR could be assembled with pirarubicin (THP), an anthracycline, to form a carrier-free nanoparticle (NP) by emulsion-solvent evaporation method. A small amount of mPEG2000-DSPE was added to shield the positive charges and improve the stability of the nanoparticle to obtain PEG-modified nanoparticle (PNP). It was proved that INR released the prototype drugs in tumor cells and hypoxia promoted the release. The Golgi destructive effect of RA in INR was amplified owing to the Golgi targeting ability of IMC, and IMC also inhibited the protumor COX-2/PGE2 signaling. Finally, PNP exhibited excellent curative efficacy on 4T1 primary tumor and its pulmonary and hepatic metastasis. The small molecular therapeutic prodrug targeting Golgi apparatus could be adapted to multifarious drug delivery systems and disease models, which expanded the application of Golgi targeting tactics in disease treatment.

Acetylation and Phosphorylation in the Regulation of Hypoxia-Inducible Factor Activities: Additional Options to Modulate Adaptations to Changes in Oxygen Levels

O2 is essential for the life of eukaryotic cells. The ability to sense oxygen availability and initiate a response to adapt the cell to changes in O2 levels is a fundamental achievement of evolution. The key switch for adaptation consists of the transcription factors HIF1A, HIF2A and HIF3A. Their levels are tightly controlled by O2 through the involvement of the oxygen-dependent prolyl hydroxylase domain-containing enzymes (PHDs/EGNLs), the von Hippel-Lindau tumour suppressor protein (pVHL) and the ubiquitin-proteasome system. Furthermore, HIF1A and HIF2A are also under the control of additional post-translational modifications (PTMs) that positively or negatively regulate the activities of these transcription factors. This review focuses mainly on two PTMs of HIF1A and HIF2A: phosphorylation and acetylation.

Renal Cell Carcinoma in End-Stage Kidney Disease and the Role of Transplantation

Kidney transplant patients have a higher risk of renal cell carcinoma (RCC) compared to non-transplanted end-stage kidney disease (ESKD) patients. This increased risk has largely been associated with the use of immunosuppression; however, recent genetic research highlights the significance of tissue specificity in cancer driver genes. The implication of tissue specificity becomes more obscure when addressing transplant patients, as two distinct metabolic environments are present within one individual. The oncogenic potential of donor renal tissue is largely unknown but assumed to pose minimal risk to the kidney transplant recipient (KTR). Our review challenges this notion by examining how donor and recipient microenvironments impact a transplant recipient's associated risk of renal cell carcinoma. In doing so, we attempt to encapsulate how ESKD-RCC and KTR-RCC differ in their incidence, pathogenesis, outcome, and approach to management.