HIF Inhibitors Research Articles

Marine-Derived Leads as Anticancer Candidates by Disrupting Hypoxic Signaling through Hypoxia-Inducible Factors Inhibition.

The inadequate vascularization seen in fast-growing solid tumors gives rise to hypoxic areas, fostering specific changes in gene expression that bolster tumor cell survival and metastasis, ultimately leading to unfavorable clinical prognoses across different cancer types. Hypoxia-inducible factors (HIF-1 and HIF-2) emerge as druggable pivotal players orchestrating tumor metastasis and angiogenesis, thus positioning them as prime targets for cancer treatment. A range of HIF inhibitors, notably natural compounds originating from marine organisms, exhibit encouraging anticancer properties, underscoring their significance as promising therapeutic options. Bioprospection of the marine environment is now a well-settled approach to the discovery and development of anticancer agents that might have their medicinal chemistry developed into clinical candidates. However, despite the massive increase in the number of marine natural products classified as 'anticancer leads,' most of which correspond to general cytotoxic agents, and only a few have been characterized regarding their molecular targets and mechanisms of action. The current review presents a critical analysis of inhibitors of HIF-1 and HIF-2 and hypoxia-selective compounds that have been sourced from marine organisms and that might act as new chemotherapeutic candidates or serve as templates for the development of structurally similar derivatives with improved anticancer efficacy.

Recent Advances in the Management of Diabetic Kidney Disease: Slowing Progression.

Diabetic kidney disease (DKD) is a major cause of chronic kidney disease (CKD), and it heightens the risk of cardiovascular incidents. The pathogenesis of DKD is thought to involve hemodynamic, inflammatory, and metabolic factors that converge on the fibrotic pathway. Genetic predisposition and unhealthy lifestyle practices both play a significant role in the development and progression of DKD. In spite of the recent emergence of angiotensin receptors blockers (ARBs)/angiotensin converting enzyme inhibitor (ACEI), sodium-glucose cotransporter 2 (SGLT2) inhibitors, and nonsteroidal mineralocorticoid receptors antagonists (NS-MRAs), current therapies still fail to effectively arrest the progression of DKD. Glucagon-like peptide 1 receptor agonists (GLP-1RAs), a promising class of agents, possess the potential to act as renal protectors, effectively slowing the progression of DKD. Other agents, including pentoxifylline (PTF), selonsertib, and baricitinib hold great promise as potential therapies for DKD due to their anti-inflammatory and antifibrotic properties. Multidisciplinary treatment, encompassing lifestyle modifications and drug therapy, can effectively decelerate the progression of DKD. Based on the treatment of heart failure, it is recommended to use multiple drugs in combination rather than a single-use drug for the treatment of DKD. Unearthing the mechanisms underlying DKD is urgent to optimize the management of DKD. Inflammatory and fibrotic factors (including IL-1, MCP-1, MMP-9, CTGF, TNF-a and TGF-β1), along with lncRNAs, not only serve as diagnostic biomarkers, but also hold promise as therapeutic targets. In this review, we delve into the potential mechanisms and the current therapies of DKD. We also explore the additional value of combing these therapies to develop novel treatment strategies. Drawing from the current understanding of DKD pathogenesis, we propose HIF inhibitors, AGE inhibitors, and epigenetic modifications as promising therapeutic targets for the future.

The Role of Hypoxia-Inducible Factor 1 Alpha in Acute-on-Chronic Liver Failure.

Acute-on-chronic liver failure (ACLF) is associated with increased mortality. Specific therapy options are limited. Hypoxia-inducible factor 1 alpha (HIF-1α) has been linked to the pathogenesis of chronic liver disease (CLD), but the role of HIF-1α in ACLF is poorly understood. In the current study, different etiologies of CLD and precipitating events triggering ACLF were used in four rodent models. HIF-1α expression and the intracellular pathway of HIF-1α induction were investigated using real-time quantitative PCR. The results were verified by Western blotting and immunohistochemistry for extrahepatic HIF-1α expression using transcriptome analysis. Exploratory immunohistochemical staining was performed to assess HIF-1α in human liver tissue. Intrahepatic HIF-1α expression was significantly increased in all animals with ACLF, regardless of the underlying etiology of CLD or the precipitating event. The induction of HIF-1α was accompanied by the increased mRNA expression of NFkB1 and STAT3 and resulted in a marked elevation of mRNA levels of its downstream genes. Extrahepatic HIF-1α expression was not elevated. In human liver tissue samples, HIF-1α expression was elevated in CLD and ACLF. Increased intrahepatic HIF-1α expression seems to play an important role in the pathogenesis of ACLF, and future studies are pending to investigate the role of therapeutic HIF inhibitors in ACLF.

Yeni Sentezlenen Potansiyel HIF İnhibitörlerinin Hipoksik Koşullarda Küçük Hücre Dışı Akciğer Kanseri Üzerindeki İnhibitör Etkilerinin Belirlenmesi

According to global estimates, there are 2.3 million new cases and 1.8 million fatalities due to lung cancer each year. Despite recent progress in diagnosis and treatment, persistent challenges highlight the urgent need for novel therapeutics and innovative approaches to combat lung cancer effectively. Accordingly, in the present study, we aimed to investigate the anticancer properties of potential inhibitors of HIF-1α, compound 7a and 7b. In the study, HTB-54 and BEAS-2B cell lines were used. MTT cell viability experiments were performed to determine the effect of newly synthesized HIF inhibitors 7a and 7b on cell viability under normoxic and hypoxic conditions. Quantitative expression levels of HIF1A were determined by real-time PCR approach. While the half maximum inhibitory concentration (IC50) of compound 7a in HTB-54 cells was 10.37 µM under normoxic conditions, it was found to be 10.63 µM under hypoxic conditions. The IC50 value of another HIF inhibitor 7b in HTB-54 cells was found to be 8.80 µM under normoxic conditions and 9.54 µM under hypoxic conditions. The expression level of HIF1A was found to be lower in cells exposed to compounds 7a and 7b under hypoxia compared to the control group. Conversely, in normoxia, HIF1A expression level in cells exposed to compound 7a increased 6.5-fold (p<0.0001) compared to the control group, while it was found to increase approximately 9-fold (p<0.0001) when exposed to 7b. Consequently, both compound 7a and 7b holds great promise for future therapeutic interventions to lung cancer.

Mebendazole Treatment Disrupts the Transcriptional Activity of Hypoxia-Inducible Factors 1 and 2 in Breast Cancer Cells

Breast cancer is the most diagnosed cancer in women in the world. Mebendazole (MBZ) has been demonstrated to have preclinical efficacy across multiple cancers, including glioblastoma multiforme, medulloblastoma, colon, breast, pancreatic, and thyroid cancers. MBZ was also well tolerated in a recent phase I clinical trial of adults diagnosed with glioma. The mechanisms of action reported so far for MBZ include tubulin disruption, inhibiting angiogenesis, promoting apoptosis, and maintaining stemness. To elucidate additional mechanisms of action for mebendazole (MBZ), we performed RNA sequencing of three different breast cancer cell lines treated with either MBZ or vehicle control. We compared the top genes downregulated upon MBZ treatment with expression profiles of cells treated with over 15,000 perturbagens using the clue.io online analysis tool. In addition to tubulin inhibitors, the gene expression profile that correlated most with MBZ treatment matched the profile of cells treated with known hypoxia-inducible factor (HIF-1α and -2α) inhibitors. The HIF pathway is the main driver of the cellular response to hypoxia, which occurs in solid tumors. Preclinical data support using HIF inhibitors in combination with standard of care to treat solid tumors. Therefore, we tested the hypothesis that MBZ could inhibit the hypoxia response. Using RNA sequencing and HIF-reporter assays, we demonstrate that MBZ inhibits the transcriptional activity of HIFs in breast cancer cell lines and in mouse models of breast cancer by preventing the induction of HIF-1α, HIF-2α, and HIF-1β protein under hypoxia. Taken together, our results suggest that MBZ treatment has additional therapeutic efficacy in the setting of hypoxia and warrants further consideration as a cancer therapy.

Hypoxia Primes Human ISCs for Interleukin-Dependent Rescue of Stem Cell Activity

Hypoxia in the intestinal epithelium can be caused by acute ischemic events or chronic inflammation in which immune cell infiltration produces inflammatory hypoxia starving the mucosa of oxygen. The epithelium has the capacity to regenerate after some ischemic and inflammatory conditions suggesting that intestinal stem cells (ISCs) are highly tolerant to acute and chronic hypoxia; however, the impact of hypoxia on human ISC (hISC) function has not been reported. Here we present a new microphysiological system (MPS) to investigate how hypoxia affects hISCs from healthy donors and test the hypothesis that prolonged hypoxia modulates how hISCs respond to inflammation-associated interleukins (ILs). hISCs were exposed to <1.0% oxygen in the MPS for 6, 24, 48, and 72 hours. Viability, hypoxia-inducible factor 1a (HIF1a) response, transcriptomics, cell cycle dynamics, and response to cytokines were evaluated in hISCs under hypoxia. HIF stabilizers and inhibitors were screened to evaluate HIF-dependent responses. The MPS enables precise, real-time control and monitoring of oxygen levels at the cell surface. Under hypoxia, hISCs maintain viability until 72 hours and exhibit peak HIF1a at 24 hours. hISC activity was reduced at 24 hours but recovered at 48 hours. Hypoxia induced increases in the proportion of hISCs in G1 and expression changes in 16 IL receptors. Prolyl hydroxylase inhibition failed to reproduce hypoxia-dependent IL-receptor expression patterns. hISC activity increased when treated IL1β, IL2, IL4, IL6, IL10, IL13, and IL25 and rescued hISC activity caused by 24 hours of hypoxia. Hypoxia pushes hISCs into a dormant but reversible proliferative state and primes hISCs to respond to a subset of ILs that preserves hISC activity. These findings have important implications for understanding intestinal epithelial regeneration mechanisms caused by inflammatory hypoxia.

Axl, Immune Checkpoint Molecules and HIF Inhibitors from the Culture Broth of Lepista luscina.

Two compounds 1 and 2 were isolated from the culture broth of Lepista luscina. This is the first time that compound 1 was isolated from a natural source. The structure of compound 1 was identified via 1D and 2D NMR and HRESIMS data. Compounds 1 and 2 along with 8-nitrotryptanthrin (4) were evaluated for their biological activities using the A549 lung cancer cell line. As a result, 1 and 2 inhibited the expression of Axl and immune checkpoint molecules. In addition, compounds 1, 2 and 4 were tested for HIF inhibitory activity. Compound 2 demonstrated statistically significant HIF inhibitory effects on NIH3T3 cells and 1 and 2 against ARPE19 cells.

Conducive target range of breast cancer: Hypoxic tumor microenvironment.

Breast cancer is a kind of malignant tumor disease that poses a serious threat to human health. Its biological characteristics of rapid proliferation and delayed angiogenesis, lead to intratumoral hypoxia as a common finding in breast cancer. HIF as a transcription factor, mediate a series of reactions in the hypoxic microenvironment, including metabolic reprogramming, tumor angiogenesis, tumor cell proliferation and metastasis and other important physiological and pathological processes, as well as gene instability under hypoxia. In addition, in the immune microenvironment of hypoxia, both innate and acquired immunity of tumor cells undergo subtle changes to support tumor and inhibit immune activity. Thus, the elucidation of tumor microenvironment hypoxia provides a promising target for the resistance and limited efficacy of current breast cancer therapies. We also summarize the hypoxic mechanisms of breast cancer treatment related drug resistance, as well as the current status and prospects of latest related drugs targeted HIF inhibitors.

Discovery of new chiral sulfonamides bearing benzoxadiazole as HIF inhibitors for non-small cell lung cancer therapy: design, microwave-assisted synthesis, binding affinity,in vitroantitumoral activities andin silicostudies

Thirty-four chiral compounds having benzoxadiazole and sulfonamide moieties on the skeleton have been synthesized. The in vitro cytotoxic activity and apoptotic effects of these compounds have been evaluated using the A549 lung cancer cell line.

HIF1 and ID1 Interplay Confers Adaptive Survival to HIF1α-Inhibition.

Hypoxia is a universal pathological feature of solid tumors. Hypoxic tumor cells acquire metastatic and lethal phenotypes primarily through the activities of hypoxia-inducible factor 1 alpha (HIF1α). Therefore, HIF1α is considered as a promising therapeutic target. However, HIF inhibitors have not proven to be effective in clinical testing. The underlying mechanism is unclear. We report that oncogenic protein ID1 is upregulated in hypoxia by HIF1α shRNA or pharmacological inhibitors. In turn, ID1 supports tumor growth in hypoxia in vitro and in xenografts in vivo, conferring adaptive survival response and resistance. Mechanistically, ID1 proteins interfere HIF1-mediated gene transcription activation, thus ID1 protein degradation is accelerated by HIF1α-dependent mechanisms in hypoxia. Inhibitions of HIF1α rescues ID1, which compensates the loss of HIF1α by the upregulation of GLS2 and glutamine metabolism, thereby switching the metabolic dependency of HIF1α -inhibited cells from glucose to glutamine.

HIF-1-Independent Mechanisms Regulating Metabolic Adaptation in Hypoxic Cancer Cells.

In solid tumours, cancer cells exist within hypoxic microenvironments, and their metabolic adaptation to this hypoxia is driven by HIF-1 transcription factor, which is overexpressed in a broad range of human cancers. HIF inhibitors are under pre-clinical investigation and clinical trials, but there is evidence that hypoxic cancer cells can adapt metabolically to HIF-1 inhibition, which would provide a potential route for drug resistance. Here, we review accumulating evidence of such adaptions in carbohydrate and creatine metabolism and other HIF-1-independent mechanisms that might allow cancers to survive hypoxia despite anti-HIF-1 therapy. These include pathways in glucose, glutamine, and lipid metabolism; epigenetic mechanisms; post-translational protein modifications; spatial reorganization of enzymes; signalling pathways such as Myc, PI3K-Akt, 2-hyxdroxyglutarate and AMP-activated protein kinase (AMPK); and activation of the HIF-2 pathway. All of these should be investigated in future work on hypoxia bypass mechanisms in anti-HIF-1 cancer therapy. In principle, agents targeted toward HIF-1β rather than HIF-1α might be advantageous, as both HIF-1 and HIF-2 require HIF-1β for activation. However, HIF-1β is also the aryl hydrocarbon nuclear transporter (ARNT), which has functions in many tissues, so off-target effects should be expected. In general, cancer therapy by HIF inhibition will need careful attention to potential resistance mechanisms.

Highlights from Recent Cancer Literature

Highlights from Recent Cancer Literature

Abstract 4998: Integrative analyses in pediatric osteosarcomas to understand the role of GD2 associated to activated mTor for macrophage targeting

Abstract Osteosarcoma is the most common primary malignant bone tumor in children and young adults. Its immune environment was described as predominantly involving M2 macrophages or osteoclasts. Previous studies were observing ganglioside GD2 expression on the osteosarcoma cell surface. Even more and more publications are deciphering the role of hypoxic biomarkers and its metabolic cell impact. Nevertheless, no links were, for instance, described clearly between mTor-HIF1 pathway and the macrophages in osteosarcomas through GD2 targeting. The aim of the study was to understand the role of all those molecular partners in osteosarcoma models. Material and methods: A cohort of 35 patients was explored to determine the expression by immunohistochemistry, as well as semi-quantitative PCR of several hypoxic and macrophages' biomarkers. Additionally, in 2D and 3D in vitro osteosarcoma models, analyses using metabolomics, western blotting, immunofluorescent imaging and RNA sequencing were performed to understand functional interactions between patient-derived osteosarcoma cells and the M2 macrophages. Endly, drug screening studies were testing 3D models (integrating matrix and hypoxic microenvironment) to assess efficacy of combinations using dinutuximab, mTor and HIF inhibitors. Results: Osteosarcoma samples are highly expressing CD163 and CD68 macrophage markers, as well as activated mTORC1 and GD2. Hypoxic biomarkers, when overexpressed, were statistically linked to a worst patient outcome. For macrophages and GD2 markers, a low expression was mostly linked to metastatic disease or poor response to chemotherapy. Specific metabolomic changes through glutaminolysis were frequently present and associated to a transcriptomic signature combining metabolism changes and specific immune macrophage environment. The targeting by dinutuximab associated to hypoxia inhibition was having a clear effect on osteosarcoma cell proliferation decrease, when associated to macrophages in 3D models mimicking osteosarcoma tumors. Conclusion: Macrophage immune environment is a key component of pediatric osteosarcomas and can be targeted in association with hypoxia inhibitors in 3D models recreating the osteosarcoma immune environment and bone matrix. Citation Format: Marina Pierrevelcin, Isabelle Lelong-Rebel, Quentin Fuchs, Monique Dontenwill, Natacha Entz-Werle. Integrative analyses in pediatric osteosarcomas to understand the role of GD2 associated to activated mTor for macrophage targeting [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 4998.

Oral Submucous Fibrosis as an Overhealing Wound: Implications in Malignant Transformation.

Oral submucous fibrosis is an oral potentially malignant disorder with high incidence of malignant transformation and rising global prevalence. However, the genesis of oral submucous fibrosis is still unclear despite superfluity of literature. In the background of ineffective treatment, it is necessary to decode its onset and progression before designing customized treatment regimens. The objective of this article is to decipher the pathogenesis of oral submucous fibrosis in order to identify novel drug targets. A thorough literature review based on oral submucous fibrosis being an overhealing wound was conducted; several related patents were identified and herewith reviewed. Necessary pathways were elaborated and deliberated in the manuscript in the form of schemas, keeping our hypothesis in mind. Several novel molecular targets were identified and discussed in detail. Several patents demonstrating inhibition of fibrosis via chemokine ligand mimetics, anticonnexon antibodies, stem cell therapy, fibronectin blocking peptides, HIF inhibitors, recombinant erythropoietin, xanthine oxidase inhibitors, long non-coding RNAs, targeting inflammation, increasing TH-1/TH-2 cytokine ratio, t-box protein 4, chromium containing compositions, Iron-based nanocomposites, Lactate Dehydrogenase-5 inhibitors, Carbonic Anhdrase-9 inhibitors, proton pump inhibitors, liposomal encapsulated glutathione, monocarboxylate-4 inhibitors, autophagy inhibitors, Submucosal anti-IL-6 antibodies, fibrin degradation products for monitoring of malignancy and fibrosis, small molecule antagonists like vorapaxar, tiplaxtinin, and TM-5275, TGF-β signalling inhibitors were identified as future therapeutic avenues. Considering, oral submucous fibrosis as an overhealing wound explains both pathogenesis and malignant transformation. Certainly, abnormalities in coagulation and fibrinolytic system are a common denominator in the profibrotic milieu and associated malignancy.

Recent advances in the management of malignant pheochromocytoma and paraganglioma: focus on tyrosine kinase and hypoxia-inducible factor inhibitors.

Inactivating mutations of the succinate dehydrogenase subunit B ( SDHB) gene and the subsequent stabilization and activation of the hypoxia-inducible factor 2-alpha (HIF2α) unit are recognized hallmarks associated with the development of metastatic pheochromocytomas and paragangliomas (MPPG). Despite this discovery, the development of systemic therapies for patients with MPPG has been very slow. The rarity of the disease, the lack of preclinical animal models, and the impracticable development of large clinical trials has hindered the therapeutic progress for MPPG. Chemotherapy and low-specific activity 131meta-iodo-benzyl-guanidine (MIBG) (manufactured by simple isotope exchange methodology) led to positive clinical responses in about a third of patients. Molecular targeted therapies were introduced into oncological clinical practice at the beginning of the 21st century. These therapies have been demonstrated to be effective for patients with cancers that previously exhibited limited responses to systemic chemotherapy, such as kidney and thyroid carcinomas and pancreatic neuroendocrine tumors. The pathogenesis of MPPG overlaps in some way with the pathogenesis of kidney, medullary thyroid, and pancreatic neuroendocrine carcinomas, providing scientific support to explore molecular targeted therapies such as tyrosine kinase and HIF inhibitors.

Abstract 3066: Chemotherapy-induced GSTO1 interacts with ryanodine receptor RYR1 to trigger Ca2+-dependent breast cancer stem cell enrichment

Abstract Breast cancer stem cells (BCSCs) play a critical role in tumor recurrence and metastasis. Exposure of breast cancer cells to chemotherapy leads to an enrichment of BCSCs. Here, we demonstrate that chemotherapy induces the expression of glutathione S-transferase omega 1 (GSTO1), which is dependent on hypoxia-inducible factor 1 (HIF-1) and HIF-2. Knockdown of GSTO1 expression abrogates carboplatin-induced BCSC enrichment, decreases tumor initiation and metastatic capacity, and delays tumor recurrence after chemotherapy. GSTO1 interacts with ryanodine receptor RYR1 and promotes calcium release from endoplasmic reticulum. Increased cytosolic calcium levels activate PYK2 → SRC → STAT3 signaling, leading to increased expression of pluripotency factors and BCSC enrichment. HIF inhibition blocks chemotherapy-induced GSTO1 expression and BCSC enrichment. Combining HIF inhibitors with chemotherapy may improve clinical outcome in breast cancer. Citation Format: Haiquan Lu, Gregg Semenza. Chemotherapy-induced GSTO1 interacts with ryanodine receptor RYR1 to trigger Ca2+-dependent breast cancer stem cell enrichment [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 3066.

Chemotherapy-Induced Ca2+ Release Stimulates Breast Cancer Stem Cell Enrichment

Breast cancer stem cells (BCSCs) play a critical role in tumor recurrence and metastasis. Exposure of breast cancer cells to chemotherapy leads to an enrichment of BCSCs. Here, we find that chemotherapy induces the expression of glutathione S-transferase omega 1 (GSTO1), which is dependent on hypoxia-inducible factor 1 (HIF-1) and HIF-2. Knockdown of GSTO1 expression abrogates carboplatin-induced BCSC enrichment, decreases tumor initiation and metastatic capacity, and delays tumor recurrence after chemotherapy. GSTO1 interacts with the ryanodine receptor RYR1 and promotes calcium release from the endoplasmic reticulum. Increased cytosolic calcium levels activate PYK2 → SRC → STAT3 signaling, leading to increased expression of pluripotency factors and BCSC enrichment. HIF inhibition blocks chemotherapy-induced GSTO1 expression and BCSC enrichment. Combining HIF inhibitors with chemotherapy may improve clinical outcome in breast cancer.

Abstract LB-310: NADH dehydrogenase (ubiquinone) 1 alpha subcomplex 4-like 2 (NDUFA4L2) reduces oxidative stress to promote hepatocellular carcinoma

Abstract Background &amp; Aims: Liver is a major metabolic organ, yet the detailed metabolic alterations driving hepatocellular carcinoma (HCC) remain elusive. The rapid growing nature of HCC results in oxygen deprivation or hypoxia in regions of tumors with insufficient blood supply. Hypoxia unbalances the electron flow through the electron transport chain (ETC) resulting in reactive oxygen species (ROS) accumulation. Here we aim at delineating the mechanisms by which HCC evades oxidative stress. Methods: We performed transcriptome sequencing to study the gene expression profile in both HCC patients and HCC cell line. The mRNA expression of 100 paired HCC and corresponding non-tumorous tissues were analyzed. Stable RNAi knockdown by shRNA and genetic knockout by TALEN were established in HCC cells for functional characterization. Results: We demonstrated that HCC cells specifically utilized the mitochondrial protein NADH dehydrogenase (ubiquinone) 1 alpha subcomplex 4-like 2 gene (NDUFA4L2), in the complex I of the ETC, to survive hypoxia. NDUFA4L2 was drastically over-expressed in human HCC and closely associated with poor clinical outcomes in HCC patients. We confirmed that NDUFA4L2 was regulated by HIF-1α in HCC cells. Inactivation of HIF-1α/NDUFA4L2 in different HCC cell lines increased mitochondrial activity and oxygen consumption, resulting in ROS accumulation and ROS-mediated apoptosis in HCC cells. Knockdown of NDUFA4L2 markedly suppressed HCC growth and metastasis in vitro and in vivo. In addition, HIF inhibitors, digoxin and sorafenib, significantly suppressed growth of tumors that expressed high level of NDUFA4L2 in orthotopic HCC model. Conclusions: Our results have unprecedentedly uncovered the clinical relevance and oncogenic roles of NDUFA4L2 in HCC. Citation Format: Robin Kit-Ho Lai, Irix Ming-Jing Xu, David Kung-Chun Chiu, Aki Pui-Wah Tse, Larry Lai Wei, Cheuk-Ting Law, Derek Lee, Chun-Ming Wong, Maria Pik Wong, Irene Oi-Lin Ng, Carmen Chak Lui Wong. NADH dehydrogenase (ubiquinone) 1 alpha subcomplex 4-like 2 (NDUFA4L2) reduces oxidative stress to promote hepatocellular carcinoma. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr LB-310.

HIF Inhibitors: New Hope for Cancer Therapy

Cancer remains a critical study since long period. Inspite of remarkable development in science, still suitable cure and treatment is not available. In humans, Hypoxia-inducible factor-1 (HIF-1) is available in good amount in tumors and is associated in various mechanisms such as metabolism of anaerobic energy, angiogenesis, drug resistance, cell subsistence and incursion etc. Hence, for the treatment of cancer, HIF-1 inhibition may be considered as an obvious strategy. Recent studies illustrate many advances in cancer biology and biotechnology for targeting new HIF-1 agents. Numerous heterocyclic compounds are available as anticancer agents and countless struggles have been placed to discover unique agents in the coming years, which can be considered as an important tool for the diagnosis of cancer. This review provides a vision for novel anticancer targets and highlights rationally designed drugs in clinical advancement, and also the budding molecules that can influence clinical care in the coming future. Although several anticancer treatments have been familiarized in the recent years, however, none of them stand up for a better cure and because of which a new and advanced treatment becomes obligatory. Keywords: Anticancer agents, cancer, heterocyclic compounds, HIF, synthesis, treatment.

Abstract 1188: HIF-1α/NDUFA4L2 promotes hepatocellular carcinoma progression through reducing oxidative stress

Abstract Background: Liver is well characterized as a major metabolic organ, the metabolic machineries driving liver cancer (hepatocellular carcinoma, HCC) progression remains poorly understood. Oxygen deprivation, hypoxia, is frequently found in regions of tumors with insufficient blood supply. Hypoxia stabilizes hypoxia-inducible factor-1α (HIF-1α) which transcriptionally activates genes that utilize glycolysis over oxidative phosphorylation for ATP production. This metabolic switch reduces mitochondrial reactive oxygen species (ROS) production that would otherwise occur due to electron imbalance through the electron transport chain (ETC) in hypoxic condition. In our transcriptome sequence analysis, among all the mitochondrial subunits in the complex I of the electron transport chain (ETC), only NADH dehydrogenase (ubiquinone) 1 alpha subcomplex 4-like 2 gene (NDUFA4L2) was distinctly and significantly induced by hypoxia and over-expressed in human HCC. However, the clinical implications and functions of this gene in HCC progression remain unknown. Methods: The mRNA expression of NDUFA4L2 in an expanded cohort of 100 HCC patients was evaluated by qRT-PCR. ChIP assay was performed to study the interaction of HIF-1α with NDUFA4L2. Stable knockdown by shRNA or knockout by TALEN of HIF-1α/NDUFA4L2 was established in HCC cells to explore the roles of NDUFA4L2 in HCC. ROS, mitochondrial membrane potential, and oxygen consumption rate were measured in the HIF-1α/NDUFA4L2 knockdown or knockout HCC cells. Orthotopic implantation model was employed to evaluate the in vivo effect of NDUFA4L2 and the efficiency of HIF inhibitors. Results: NDUFA4L2 was significantly overexpressed in human HCC and was markedly induced by hypoxia. Overexpression of NDUFA4L2 in human HCC was significantly correlated with aggressive HCC clinicopathological parameters including absence of tumor encapsulation, formation of tumor microsatellite, and poorer overall survival. ChIP assay confirmed the binding of HIF-1α with hypoxia response elements (HREs) in NDUFA4L2 promoter and expression study showed that hypoxia-induced NDUFA4L2 was abolished in HIF-1αknockdown or knockout HCC cells. Genetic ablation of HIF-1α/NDUFA4L2 increased the mitochondrial activity that coupled with higher intracellular reactive oxygen species (ROS) and ROS-induced apoptosis. Knockdown of NDUFA4L2 markedly suppressed tumor growth in vitro and in vivo. HIF inhibitors, digoxin and Sorafenib, profoundly inhibited the growth of HCC that expressed high levels of NDUFA4L2. Conclusion: Over-expression of NDUFA4L2 is associated with poor clinical outcome in HCC patients. Hypoxia-induced NDUFA4L2 reduced the mitochondrial ROS production and ROS-triggered apoptosis, thereby conferring HCC cells growth advantage in hypoxic environment. Targeting HIF-1α/NDUFA4L2 pathway by HIF inhibitors represent a new therapeutic strategy for HCC. Citation Format: Kit Ho Lai, Ming Jing Xu, Pui Wah Tse, Kung Chun Chiu, Wei Lai, Chun Ming Wong, Pik Wong, Oi Lin Ng, Chak Lui Wong. HIF-1α/NDUFA4L2 promotes hepatocellular carcinoma progression through reducing oxidative stress. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 1188. doi:10.1158/1538-7445.AM2015-1188