Hypoxia-inducible Factor Prolyl Hydroxylase Research Articles

A Prospective Randomized Controlled Clinical Study to Investigate the Efficacy and Safety of Hypoxia-Inducible Factor-Prolyl Hydroxylase Inhibitors in Non-Dialysis Patients with Chronic Heart Failure and Renal Anemia Switched from Continuous Erythropoietin Receptor Activator Treatment

Background/Objectives: Chronic kidney disease (CKD) and anemia are independent prognostic factors for heart failure. In recent years, hypoxia-inducible factor-prolyl hydroxylase (HIF-PH) inhibitors have become available for the treatment of renal anemia. This prospective randomized controlled study aimed to investigate the effects of switching from a continuous erythropoietin receptor activator (CERA) to one of four HIF-PH inhibitors in patients with chronic heart failure and renal anemia. Methods: Forty patients were randomized by the envelop method to receive treatment with roxadustat, daprodustat, vadadustat, or molidustat. The primary endpoint was the change in the hemoglobin (Hb) level. Secondary endpoints included changes in erythropoietin, changes in free T3, free T4, and thyroid-stimulating hormone (TSH), adverse effects, and drug dose increases and decreases. This study was preregistered in the University Hospital Medical Information Network Clinical Trials Registry (study ID: UMIN000041651). Results: We found no statistically significant difference between Hb levels with HIF-PH inhibitors and CERA, but at month 6, the Hb level was significantly higher with roxadustat than with vadadustat and daprodustat. Erythropoietin decreased significantly after switching to HIF-PH inhibitors. HIF-PH inhibitors had various significant effects on free T3, free T4, and TSH. No adverse events occurred. The doses of some drugs had to be increased or decreased. Conclusions: In patients with heart failure and renal anemia receiving CERA, Hb, NT-ProBNP, and renal function were similar after switching from CERA to HIF-PH inhibitors. The individual HIF-PH inhibitors appear to have different effects on anemia and thyroid function. However, because this was a single-center study with a limited sample size, the efficacy and potential limitations of HIF-PH inhibitors need to be further clarified.

Consensus commentary and position of the Italian Society of Nephrology on KDIGO controversies conference on novel anemia therapies in chronic kidney disease.

Hypoxia-inducible factor prolyl hydroxylase inhibitors (HIF-PHIs) are new drugs developed for the treatment of anemia associated with chronic kidney disease (CKD). This class of drugs stimulates endogenous erythropoietin production and, at the same time, improves iron absorption and mobilization of iron stores (less evident with daprodustat, vadadustat and enarodustat). Several studies have been published in the last few years showing that these agents are not inferior to standard therapy in correcting anemia associatedwith CKD. The efficacy of HIF-PHIs is coupled with a safety profile comparable to that of standard erythropoiesis stimulating agent (ESA) treatment. However, studies with HIF-PHIs were not long enough to definitively exclude the impact of new drugs on adverse events, such as cancer, death and possibly cardiovascular events, that usually occur after a long follow-up period. Kidney Disease: Improving Global Outcomes (KDIGO) recently reported the conclusions of the Controversies Conference on HIF-PHIs held in 2021. The goal of the present position paper endorsed by the Italian Society of Nephrology is to better adapt the conclusions of the latest KDIGO Conference on HIF-PHIs to the Italian context by reviewing the efficacy and safety of HIF-PHIs as well as their use in subpopulations of interest as emerged from more recent publications not discussed during the KDIGO Conference.

[Clinical application and future perspectives of HIF-PH inhibitors].

Anemia in chronic kidney disease (CKD) occurs due to insufficient production of erythropoietin to compensate for the decrease in hemoglobin. Anemia in CKD has traditionally been treated with periodic injections of erythropoiesis-stimulating agents (ESAs), which are recombinant human erythropoietin preparations. Although ESA improved anemia in CKD and dramatically improved the quality of life of patients, there are some patients who are hyporesponsive to ESA, and the use of large doses of ESA in these patients may have a negative impact on patient prognosis. Currently, HIF prolyl hydroxylase (HIF-PH) inhibitors have been approved in Japan as a new treatment for anemia in CKD. HIF-PH inhibitors activate HIF and promote the production of endogenous erythropoietin. The 2019 Nobel Prize in Physiology or Medicine was awarded for groundbreaking research that uncovered the HIF pathway. Because HIF-PH inhibitors improve both erythropoietin production and iron metabolism, they are expected to be effective in treating ESA hyporesponsiveness and solve the inconvenience of injectable preparations. On the other hand, its effects are systemic and multifaceted, and long-term effects must be closely monitored.

Chemistry, Analysis, and Biological Aspects of Daprodustat, A New Hypoxia Inducible Factor Prolyl Hydroxylase Inhibitor: A Comprehensive Review.

The National Health and Nutrition Examination Survey (NHANES) carried out a survey between 2007-10 and found that as compared to the general population, the prevalence of anemia in chronic kidney disease (CKD) patients was twice high. Daprodustat is an investigational novel drug for the treatment of renal anemia. The objective of this study is to provide a comprehensive review of chemistry, synthesis, pharmacology, pharmacokinetic, and bioanalytical methods for the analysis of Daprodustat. To improve understanding, a review was carried out by creating a database of relevant prior research from electronic sources such as ScienceDirect and PubMed. The methodology is shown in the flowchart of the literature selection process. The drug was approved in 2020 for therapeutic purposes in Japan. It is a novel drug approved for the treatment of anemia in chronic kidney disease for oral administration. It is intended for adults who have undergone dialysis for a minimum of four months and are experiencing anemia as a result of chronic kidney disease. This review examines therapeutic, pharmacological, and analytical aspects related to the novel drug Daprodustat.

A retrospective study on the efficacy of Roxadustat in peritoneal dialysis patients with erythropoietin hyporesponsiveness.

Roxadustat, an oral medication for treating renal anemia, is a hypoxia-inducible factor prolyl hydroxylase inhibitor used for regulating iron metabolism and promoting erythropoiesis. To investigate the efficacy and safety of roxadustat in patients undergoing peritoneal dialysis (PD) with erythropoietin hyporesponsiveness. Single-center, retrospective study, 81 PD patients (with erythropoietin hyporesponsiveness) were divided into the roxadustat group (n = 61) and erythropoiesis-stimulating agents (ESAs) group (n = 20). Hemoglobin (Hb), total cholesterol, intact parathyroid hormone (iPTH), brain natriuretic peptide (BNP), related indicators of cardiac function and high-sensitivity C-reactive protein (hs-CRP) were collected. Additionally, adverse events were also recorded. The follow-up period was 16 weeks. The two groups exhibited similar baseline demographic and clinical characteristics. At baseline, the roxadustat group had a mean Hb level of 89.8 ± 18.9 g/L, while the ESAs group had a mean Hb level of 95.2 ± 16.0 g/L. By week 16, the Hb levels had increased to 118 ± 19.8 g/L (p < 0.05) in the roxadustat group and 101 ± 19.3 g/L (p > 0.05) in the ESAs group. The efficacy of roxadustat in improving anemia was not influenced by baseline levels of hs-CRP and iPTH. Cholesterol was decreased in the roxadustat group without statin use. An increase in left ventricular ejection fraction and stabilization of BNP were observed in the roxadustat group. For PD patients with erythropoietin hyporesponsiveness, roxadustat can significantly improve renal anemia. The efficacy of roxadustat in improving renal anemia was not affected by baseline levels of hs-CRP0 and iPTH.

The selective prolyl hydroxylase inhibitor IOX5 stabilizes HIF-1α and compromises development and progression of acute myeloid leukemia.

Acute myeloid leukemia (AML) is a largely incurable disease, for which new treatments are urgently needed. While leukemogenesis occurs in the hypoxic bone marrow, the therapeutic tractability of the hypoxia-inducible factor (HIF) system remains undefined. Given that inactivation of HIF-1α/HIF-2α promotes AML, a possible clinical strategy is to target the HIF-prolyl hydroxylases (PHDs), which promote HIF-1α/HIF-2α degradation. Here, we reveal that genetic inactivation of Phd1/Phd2 hinders AML initiation and progression, without impacting normal hematopoiesis. We investigated clinically used PHD inhibitors and a new selective PHD inhibitor (IOX5), to stabilize HIF-α in AML cells. PHD inhibition compromises AML in a HIF-1α-dependent manner to disable pro-leukemogenic pathways, re-program metabolism and induce apoptosis, in part via upregulation of BNIP3. Notably, concurrent inhibition of BCL-2 by venetoclax potentiates the anti-leukemic effect of PHD inhibition. Thus, PHD inhibition, with consequent HIF-1α stabilization, is a promising nontoxic strategy for AML, including in combination with venetoclax.

Strategies for Managing Anemia in Chronic Kidney Disease

Anemia is a common complication in chronic kidney disease (CKD) and is associated with decreased quality of life, deteriorating kidney function, increased illness, higher mortality rates, and elevated healthcare costs. Management of CKD-related anemia aims to enhance renal function (when feasible) and bolster red blood cell production. Anemia in chronic kidney disease (CKD) stems from a variety of factors, including reduced erythropoietin (EPO) production, inadequate iron availability or functionality, and inflammation leading to heightened levels of hepcidin, among other causes. Typical treatment for CKD-related anemia involves administering oral or intravenous iron supplements in conjunction with erythropoiesis-stimulating agents (ESAs). Over the past decade, erythropoiesis-stimulating agents (ESAs) have proven effective in boosting hemoglobin (Hb) levels for many patients. However, concerns about their safety, particularly regarding increased cardiovascular risk—especially at high doses and in hyporesponsive patients—have emerged. As a result, there's been a shift towards adopting more cautious Hb targets. Iron deficiency is widespread among CKD patients, particularly in those not undergoing dialysis. While iron supplementation has traditionally been used to support anemia management, there's growing recognition of the potential benefits of intravenous iron therapy, especially in the context of heart failure. HIF prolyl hydroxylase inhibitors are promising new drugs being clinically evaluated as alternatives to ESAs for anemia treatment in CKD patients. Initial data suggest they effectively boost endogenous erythropoietin production with potential benefits like lower peak concentrations, efficacy in inflamed patients, and improved iron utilization. However, further research is needed to confirm their safety and efficacy in the long term use.&#x0D; Keywords: anemia, chronic kidney disease, erythropoiesis-stimulating agents, iron, HIF-prolyl-hydroxylase inhibitors

Daprodustat: A Hypoxia-Inducible Factor-Prolyl Hydroxylase Inhibitor for Anemia of Chronic Kidney Disease.

The objective was to review the safety and efficacy of daprodustat, a hypoxia-inducible factor-prolyl hydroxylase inhibitor (HIF-PHI) in the treatment of anemia of chronic kidney disease (CKD). A literature search was conducted in MEDLINE, EMBASE, and ClinicalTrials.gov using the keywords "daprodustat," "GSK1278863," and "hypoxia-inducible factor-prolyl hydroxylase inhibitors" from January 2010 through November 2023. Literature was included if it evaluated pharmacology, pharmacokinetics, efficacy, and/or safety of daprodustat in human subjects and was reported in English. The manufacturer's product monograph was also utilized. Daprodustat significantly increased hemoglobin levels in CKD patients on dialysis (difference 0.18 g/dL) and not on dialysis (difference 0.08 g/dL) over 52-week treatment periods compared with erythropoiesis stimulating agents (ESA) in Anemia Studies in CKD: Erythropoiesis via a Novel PHI Daprodustat (ASCEND)-D and ASCEND-ND, respectively. First occurrence of major adverse cardiovascular events (MACEs) was similar between daprodustat and ESAs in both trials. Daprodustat can be used in patients with CKD on dialysis and already receiving an ESA for at least 6 weeks to further increase serum hemoglobin levels without increasing the risk of MACE. Adverse effects of daprodustat that may occur more than ESAs include headache, emesis, and thrombosis. Daprodustat is a novel oral, non-iron therapy for treatment of anemia of CKD. It was Food and Drug Administration approved in 2023 in patients already receiving dialysis for at least 4 months but not in non-dialysis patients. Long-term data for safety and additional benefits are pending.

The drug-specific properties of hypoxia-inducible factor-prolyl hydroxylase inhibitors in mice reveal a significant contribution of the kidney compared to the liver to erythropoietin induction

AimsKidney disease often leads to anemia due to a defect in the renal production of the erythroid growth factor erythropoietin (EPO), which is produced under the positive regulation of hypoxia-inducible transcription factors (HIFs). Chemical compounds that inhibit HIF-prolyl hydroxylases (HIF-PHs), which suppress HIFs, have been developed to reactivate renal EPO production in renal anemia patients. Currently, multiple HIF-PH inhibitors, in addition to conventional recombinant EPO reagents, are used for renal anemia treatment. This study aimed to elucidate the therapeutic mechanisms and drug-specific properties of HIF-PH inhibitors. Methods and key findingsGene expression analyses and mass spectrometry revealed that HIF-PH inhibitors (daprodustat, enarodustat, molidustat, and vadadustat) alter Epo gene expression levels in the kidney and liver in a drug-specific manner, with different pharmacokinetics in the plasma and urine after oral administration to mice. The drug specificity revealed the dominant contribution of EPO induction in the kidneys rather than in the liver to plasma EPO levels after HIF-PH inhibitor administration. We also found that several HIF-PH inhibitors directly induce duodenal gene expression related to iron intake, while these drugs indirectly suppress hepatic hepcidin expression to mobilize stored iron for hemoglobin synthesis through induction of the EPO-erythroferrone axis. SignificanceRenal EPO induction is the major target of HIF-PH inhibitors for their therapeutic effects on erythropoiesis. Additionally, the drug-specific properties of HIF-PH inhibitors in EPO induction and iron metabolism have been shown in mice, providing useful information for selecting the proper HIF-PH inhibitor for each renal anemia patient.

The role of hypoxia in chronic kidney disease: a nuanced perspective.

This review critically examines the role of hypoxia in chronic kidney disease (CKD). While traditionally viewed as detrimental, recent insights suggest a more nuanced understanding of hypoxia's role during renal disease. Emerging evidence challenges the traditional view that hypoxia is universally harmful in CKD context. We review here the recent evidence about hypoxia and HIF activation in CKD. We also discuss the effect of hypoxia on the renal tissue, and the relative inhibition of different HIF isoforms. Recent advancements in therapies, such as HIF prolyl hydroxylase inhibitors (HIF-PHIs) and sodium-glucose cotransporter 2 (SGLT2) inhibitors seem to target the HIF pathway. These drugs impact anemia associated with CKDbut also renoprotection, hinting at a more complex interplay between hypoxia, HIF activation, and renal health. A certain level of hypoxia and specific HIF pathway activation, especially HIF-α, can be beneficial in CKD progression. Therapeutic strategies targeting HIF stabilization, such as with HIF-PHIs and SGLT2 inhibitors, offer promising avenues for enhancing renal protection. Future investigations should aim at better understanding the precise effects on HIF pathway and optimize their clinical application to improve outcomes for CKD patients.

Hypoxia-inducible factor prolyl hydroxylase inhibitors for anaemia in chronic kidney disease: a document by the European Renal Best Practice board of the European Renal Association.

Anaemia is a common complication of chronic kidney disease (CKD) and is associated with poor long-term outcomes and quality of life. The use of supplemental iron, erythropoiesis stimulating agents (ESAs) and blood transfusions has been the mainstay of treatment of anaemia in CKD for more than three decades. Despite available treatments, CKD patients with anaemia are undertreated and moderate-to-severe anaemia remains prevalent in the CKD population. Anaemia has consistently been associated with greater mortality, hospitalisation, cardiovascular events, and CKD progression in patients with CKD, and the risk increases with anaemia severity. Hypoxia-inducible factor (HIF) prolyl hydroxylase (PH) inhibitors have a novel mechanism of action by mimicking the body's response to hypoxia and have emerged as an alternative to ESAs for the treatment of anaemia in CKD. Their efficacy in correcting and maintaining haemoglobin has been demonstrated in over 30 phase 3 clinical trials. Additionally, HIF activation results in various pleiotropic effects beyond erythropoiesis with cholesterol reduction and improved iron homeostasis and potential anti-inflammatory effects. The long-term safety of these agents, particularly with respect to cardiovascular and thromboembolic events, and their possible effect on tumor growth requires to be fully elucidated. This document presents in detail the effects of HIF-PH inhibitors, describes their mechanisms of action and pharmacologic properties, and discusses their place in the treatment of anaemia in CKD according to the available evidence.

Anemia in patients receiving anticancer treatments: focus on novel therapeutic approaches.

Anemia is common in cancer patients and impacts on quality of life and prognosis. It is typically multifactorial, often involving different pathophysiological mechanisms, making treatment a difficult task. In patients undergoing active anticancer treatments like chemotherapy, decreased red blood cell (RBC) production due to myelosuppression generally predominates, but absolute or functional iron deficiency frequently coexists. Current treatments for chemotherapy-related anemia include blood transfusions, erythropoiesis-stimulating agents, and iron supplementation. Each option has limitations, and there is an urgent need for novel approaches. After decades of relative immobilism, several promising anti-anemic drugs are now entering the clinical scenario. Emerging novel classes of anti-anemic drugs recently introduced or in development for other types of anemia include activin receptor ligand traps, hypoxia-inducible factor-prolyl hydroxylase inhibitors, and hepcidin antagonists. Here, we discuss their possible role in the treatment of anemia observed in patients receiving anticancer therapies.

The Efficacy and Safety of Roxadustat for the Treatment of Posttransplantation Anemia: A Randomized Study

IntroductionRoxadustat, an oral hypoxia-inducible factor prolyl hydroxylase inhibitor, can stimulate erythropoiesis. Our objective was to evaluate the efficacy and safety of roxadustat for the treatment of post-transplantation anemia (PTA). MethodsA total of 150 adult renal transplant recipients who underwent PTA were randomized to either the experimental group or the control group. During the 12-week randomized phase, the experimental group was randomized to oral iron and roxadustat treatment, and the control group was randomized to oral iron treatment only. The randomized phase was followed by a 12-week extended treatment period in which all participants were prescribed roxadustat treatment according to hemoglobin (Hb) levels. All the participants were followed up every 4 weeks. The primary endpoints were the change in Hb levels and response rate throughout the randomized period. ResultsA total of 128 participants completed the randomized treatment period (90 in the experimental group and 38 in the control group). The mean Hb concentration at week 12 was 12.20 g/dL in the experimental group and 11.19 g/dL in the control group. A significantly higher proportion of participants who achieved Hb responses were in the experimental group than in the control group. Differences in serum iron, total iron-binding capacity (TIBC) and transferrin from baseline to week 8-12 were significant between the two groups. The adverse event profiles were comparable between the two groups. ConclusionsRoxadustat increased Hb in adult renal transplant recipients who underwent PTA, with an adverse event profile comparable to that of the control group.

OATP1B-mediated hepatic uptake of low-molecular weight acid compounds: assessment of HIF prolyl-hydroxylase inhibitors (DUSTATS)

OATP1B-mediated hepatic uptake of low-molecular weight acid compounds: assessment of HIF prolyl-hydroxylase inhibitors (DUSTATS)

Roxadustat and transfusional iron overload induced hypothyroidism in a hemodialysis patient: a case report with a literature review

BackgroundAlthough roxadustat has been reported to cause central hypothyroidism, the details of the mechanisms and clinical characteristics of patients who are prone to developing hypothyroidism with roxadustat are uncertain.Case presentationA 53-year-old man with a 3-year history of hemodialysis due to diabetic kidney disease who had been treated with roxadustat, a hypoxia-inducible factor prolyl hydroxylase inhibitor, for 2 years was admitted to the hospital because of worsening gait disturbance and impaired consciousness. He had also acquired pure red cell aplasia associated with T-cell large granular lymphocytic leukemia and received multiple blood transfusions. Because his serum concentration of thyroid hormones was low, we diagnosed him with hypothyroidism, and his consciousness level recovered to normal with thyroid hormone replacement therapy. Computed tomography revealed a high-intensity atrophic thyroid gland, and magnetic resonance imaging showed diffusely reduced T2 and T1 signals of the pituitary anterior gland. These findings confirmed the accumulation of iron in the pituitary and thyroid glands. Combined pituitary stimulation tests with thyrotropin-releasing hormone, luteinizing hormone-releasing hormone, and corticotropin-releasing hormone revealed that the patient had pan-hypopituitarism. After discontinuation of roxadustat, the patient was treated with another hypoxia-inducible factor prolyl hydroxylase inhibitor, vadadustat. One month after switching medication, a stimulation test with thyrotropin-releasing hormone showed normal responses to thyroid-stimulating hormone. The patient was treated with levothyroxine 50 μg daily without any significant symptoms and is currently under follow-up observation as an outpatient.ConclusionsWe encountered a dialysis patient with roxadustat-induced hypothyroidism associated with transfusion iron overload. To our knowledge, this is the first case to clearly show that roxadustat can impair thyroid-stimulating hormone secretion in repeated thyrotropin-releasing hormone stimulation tests. Because the present patient had received roxadustat for more than 2 years before hypothyroidism became apparent, regular monitoring of the thyroid function may be needed in patients with renal anemia who have been treated with roxadustat, especially those at high risk of thyroid dysfunction.

Factors affecting responsiveness of vadadustat in patients with anemia associated with chronic kidney disease: a post-hoc subgroup analysis of Japanese phase 3 randomized studies

BackgroundVadadustat is an oral hypoxia-inducible factor prolyl hydroxylase inhibitor developed for treating anemia in chronic kidney disease (CKD). The purpose of this post-hoc analysis was to investigate the factors affecting the responsiveness to vadadustat in anemia patients with nondialysis-dependent (NDD) or hemodialysis-dependent (HDD) CKD in two Japanese phase 3 studies.MethodsOf 151 and 162 patients enrolled in NDD-CKD and HDD-CKD studies, 136 and 140 patients, respectively, were included and divided into subgroups for the analysis. To assess vadadustat responsiveness, the resistance index was defined as the mean body weight-adjusted dose of vadadustat (mg/kg) at weeks 20–24 divided by the mean hemoglobin (g/dL) at weeks 20–24. Multivariate analysis was performed to identify the variables affecting the resistance index.ResultsIndependent factors identified as determinants for better response to vadadustat were as follows: high baseline hemoglobin, low baseline eGFR, high week-20–24 ferritin, and CKD not caused by autoimmune disease/glomerulonephritis/vasculitis in NDD-CKD; and male sex, high baseline C-reactive protein, and low baseline erythropoiesis-stimulating agent resistance index (ERI) in HDD-CKD.ConclusionsIn this post-hoc analysis, several factors were identified as affecting the response to vadadustat. These results may provide useful information leading to an appropriate dose modification for vadadustat.Clinical trial registrationNCT03329196 (MT-6548-J01) and NCT03439137 (MT-6548-J03).

Positive response of a hemodialysis patient with pure red cell aplasia on recombinant human erythropoietin therapy to cyclosporine and Roxadustat.

Recombinant human erythropoietin (rHuEPO) is commonly used to treat anemia associated with chronic kidney disease (CKD). EPO-induced Pure Red Cell Aplasia (PRCA) is a rare condition of profound anemia with EPO treatment. Upon finding the development of EPO-induced PRCA, the treatment requires immediate withdrawal of EPO therapy and initiate new treatments with immunosuppression or renal transplantation. Anti-EPO antibody assay is not always positive in EPO-induced PRCA. Here, we report a case on the sudden development of PRCA in a hemodialysis patient receiving EPO and how we treated the condition successfully with cyclosporine and subsequently maintained the hemoglobin with Roxadustat, a hypoxia-inducible factor prolyl hydroxylase inhibitor (HIF-PHI). Even though the anti-EPO antibody was negative by Enzyme Linked Immunosorbent Assay (ELISA) in our case, the clinical course, the markedly reduced reticulocyte count < 10,000/μL, the bone marrow (BM) biopsy revealing reduced erythroblasts, and its subsequent response to cyclosporine, were similar to EPO-induced PRCA. The clinical picture of EPO-induced PRCA, the limitation of the EPO-neutralizing antibody (Ab) assay, and treatment strategies were discussed.

Abstract 390: Direct interaction of Pin1 with HIF-prolyl hydroxylase 2: Implications for breast cancer cell growth and survival

Abstract Prolyl hydroxylase domain 2 (PHD2) is the main hypoxia-inducible factor (HIF)-prolyl hydroxylase. PHD2 in normoxia hydroxylates specific proline residues in HIF-1α and HIF-2α, which facilitates their ubiquitination and proteasomal degradation. Although the activity of PHD2 is reduced in hypoxia, significant levels of residual activity of this monooxygenase are still detected under hypoxic conditions. However, its role under hypoxia is poorly understood. Peptidyl-prolyl isomerase (Pin1) binds to target proteins containing phosphorylated serine or threonine residues followed by proline (pS/T-P). As PHD2 harbors several pS/T-P motifs, it may be a potential substrate of Pin1. We found for the first time interaction between Pin1 and PHD2 in human breast cancer MDA-MB-231 cells in normoxic and hypoxic conditions. Additionally, the breast cancer tissue array showed elevated expression of PHD2 as well as Pin1 in tumors compared to adjacent normal tissues. LC-MS/MS spectrometry identified three amino acid residues (S125, T168, and S174) of PHD2 undergoing phosphorylation. Among these, serine 125 was found to be the principal site required for Pin1 binding. As a novel binding partner of Pin1, oncogenic PHD2 can be explored as a therapeutic target for the treatment of breast cancer. Citation Format: Yanymee Nimesia Guillen Quispe, Su-Jung Kim, Soma Saeidi, Gyo-Jin Choi, Chaithanya Chelakkot, Tianchi Zhou, Sang-Beom Bang, Tae-Won Kim, Young-Kee Shin, Young-Joon Surh. Direct interaction of Pin1 with HIF-prolyl hydroxylase 2: Implications for breast cancer cell growth and survival [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 390.

Abstract 386: BACH1 is a key regulator of the tumor hypoxia response

Abstract Hypoxia is an important hallmark of aggressive solid tumors and a key driver of metastasis and resistance to therapy. Hypoxic stress induces the activation of various factors, such as hypoxia-inducible factors (HIFs), which facilitate cellular adaptation and promote tumorigenesis. Given the complexity of this mechanism, identifying novel targets that sensitize hypoxic tumors to therapy could have significant clinical impact. Here we show that the pro-metastatic BTB and CNC homology 1 (BACH1) transcription factor is prolyl-hydroxylated by the HIF Prolyl Hydroxylase (PHD), similar to HIFs, in an oxygen-dependent manner. We describe two major prolyl hydroxylation sites in BACH1 and demonstrate that prolyl hydroxylation increases protein turnover and decreases DNA binding in normoxia. We further demonstrate HIF-independent induction of BACH1 within multiple TNBC (Triple-Negative Breast Cancer) cell lines and patient-derived organoids under hypoxic conditions. Utilizing ChIP-seq, bulk, single-cell and spatial transcriptomics across diverse BACH1 knockout tumor models, our study revealed that BACH1 selectively and directly modulates the transcriptional response associated with hypoxia and stress in TNBC. Our findings identify BACH1 as a clinically relevant target for attenuating hypoxia induced, pro-metastatic signaling and therapeutic resistance in cancers. Citation Format: Long Chi Nguyen, Christopher Dann, Dongbo Yang, Madeline Henn, Emily Shi, Thomas Li, Letícia Stock, Wenchao Liu, Margarite Matossian, Andrea Valdespino, Yoo Jane Han, Jing Zhang, Geetha Priyanka Yerradoddi, Yan Li, Mitsuyo Matsumoto, Olufunmilayo I. Olopade, Kazuhiko Igarashi, Marsha R. Rosner. BACH1 is a key regulator of the tumor hypoxia response [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 386.

Efficacy and safety analysis of hypoxia-inducible factor prolyl hydroxylase inhibitors for anemia in low-risk myelodysplastic syndromes patients

Myelodysplastic syndromes is a heterogeneous group of myeloid neoplastic disorders originating from hematopoietic stem cells and manifesting as pathological bone marrow hematopoiesis and a high risk of transformation to acute myeloid leukemia. In low-risk patients, the therapeutic goal is to improve hematopoiesis and quality of life. Roxadustat is the world's first oral small-molecule hypoxia-inducible factor prolyl hydroxylase inhibitor, which, unlike conventional erythropoietin, corrects anemia through various mechanisms. In this study, we retrospectively analyzed the changes in anemia, iron metabolism, lipids and inflammatory indexes in patients with low-risk myelodysplastic syndromes to evaluate its therapeutic efficacy and safety, and to provide theoretical and practical data for the application of roxadustat in myelodysplastic syndromes.