Anti-Tumor Effects of Second Generation β-Hydroxylase Inhibitors on Cholangiocarcinoma Development and Progression

Aspartate β-Hydroxylase Is Upregulated in Head and Neck Squamous Cell Carcinoma and Regulates Invasiveness in Cancer Cell Models

Aspartate β-hydroxylase (ASPH) is a protein associated with malignancy in a wide range of tumors. We hypothesize that inhibition of ASPH activity could have anti-tumor properties in patients with head and neck cancer. In this study, we screened tumor tissues of 155 head and neck squamous cell carcinoma (HNSCC) patients for the expression of ASPH using immunohistochemistry. We used an ASPH inhibitor, MO-I-1151, known to inhibit the catalytic activity of ASPH in the endoplasmic reticulum, to show its inhibitory effect on the migration of SCC35 head and neck cancer cells in cell monolayers and in matrix-embedded spheroid co-cultures with primary cancer-associated fibroblast (CAF) CAF 61137 of head and neck origin. We also studied a combined effect of MO-I-1151 and HfFucCS, an inhibitor of invasion-blocking heparan 6-O-endosulfatase activity. We found ASPH was upregulated in HNSCC tumors compared to the adjacent normal tissues. ASPH was uniformly high in expression, irrespective of tumor stage. High expression of ASPH in tumors led us to consider it as a therapeutic target in cell line models. ASPH inhibitor MO-I-1151 had significant effects on reducing migration and invasion of head and neck cancer cells, both in monolayers and matrix-embedded spheroids. The combination of the two enzyme inhibitors showed an additive effect on restricting invasion in the HNSCC cell monolayers and in the CAF-containing co-culture spheroids. We identify ASPH as an abundant protein in HNSCC tumors. Targeting ASPH with inhibitor MO-I-1151 effectively reduces CAF-mediated cellular invasion in cancer cell models. We propose that the additive effect of MO-I-1151 with HfFucCS, an inhibitor of heparan 6-O-endosulfatases, on HNSCC cells could improve interventions and needs to be further explored.

Heterogeneous Response of Tumor Cell Lines to Inhibition of Aspartate β-hydroxylase

Background: Cancer development involves alterations in key cellular pathways, with aspartate β-hydroxylase (ASPH) emerging as an important player in tumorigenesis. ASPH is upregulated in various cancer types, where it promotes cancer progression mainly by regulating the Notch1 and SRC pathways. Methods: This study explored the responses of various human cervical, pharyngeal, and breast tumor cell lines to second- and third-generation ASPH inhibitors (MO-I-1151 and MO-I-1182) using proliferation, migration, and invasion assays; western blotting; and cell cycle analysis. Results: ASPH inhibition significantly reduced cell proliferation, migration, and invasion and disrupted both the canonical and noncanonical Notch1 pathways. The noncanonical pathway was particularly mediated by AKT signaling. Cell cycle analysis revealed a marked reduction in cyclin D1 expression, further confirming the inhibitory effect of ASPH inhibitors on cell proliferation. Additional analysis revealed G0/G1 arrest and restricted progression into S phase, highlighting the regulatory impact of ASPH inhibitors on the cell cycle. Furthermore, ASPH inhibition induced distinctive alterations in nuclear morphology. The high heterogeneity in the responses of individual tumor cell lines to ASPH inhibitors, both quantitatively and qualitatively, underscores the complex network of mechanisms that are regulated by ASPH and influence the efficacy of ASPH inhibition. The effects of ASPH inhibitors on Notch1 pathway activity, cyclin D1 expression, and nuclear morphology contribute to the understanding of the multifaceted effects of these inhibitors on cancer cell behavior. Conclusion: This study not only suggests that ASPH inhibitors are effective against tumor cell progression, in part through the induction of cell cycle arrest, but also highlights the diverse and heterogeneous effects of these inhibitors on the behavior of tumor cells of different origins.

Elevated 2-oxoglutarate antagonizes DNA damage responses in cholangiocarcinoma chemotherapy through regulating aspartate beta-hydroxylase

Cholangiocarcinoma (CCA) is resistant to systemic chemotherapies that kill malignant cells mainly through DNA damage responses (DDRs). Recent studies suggest that the involvement of 2-oxoglutarate (2-OG) dependent dioxygenases in DDRs may be associated with chemoresistance in malignancy, but how 2-OG impacts DDRs in CCA chemotherapy remains elusive. We examined serum 2-OG levels in CCA patients before receiving chemotherapy. CCA patients are classified as progressive disease (PD), partial response (PR), and stable disease (SD) after receiving chemotherapy. CCA patients classified as PD showed significantly higher serum 2-OG levels than those defined as SD and PR. Treating CCA cells with 2-OG reduced DDRs. Overexpression of full-length aspartate beta-hydroxylase (ASPH) could mimic the effects of 2-OG on DDRs, suggesting the important role of ASPH in chemoresistance. Indeed, the knockdown of ASPH improved chemotherapy in CCA cells. Targeting ASPH with a specific small molecule inhibitor also enhanced the effects of chemotherapy. Mechanistically, ASPH modulates DDRs by affecting ATM and ATR, two of the major regulators finely controlling DDRs. More importantly, targeting ASPH improved the therapeutic potential of chemotherapy in two preclinical CCA models. Our data suggested the impacts of elevated 2-OG and ASPH on chemoresistance through antagonizing DDRs. Targeting ASPH may enhance DDRs, improving chemotherapy in CCA patients.

Aspartate β-hydroxylase Regulates Expression of Ly6 Genes

Background: Overexpression of aspartate β-hydroxylase (ASPH) in human tumors contributes to their progression by stimulating cell proliferation, migration, and invasion. Several signaling pathways affected by ASPH have been identified, but the high number of potential targets of ASPH hydroxylation suggests that additional mechanisms may be involved. This study was performed to reveal new targets of ASPH signaling. Methods: The effect of ASPH on the oncogenicity of three mouse tumor cell lines was tested using proliferation assays, transwell assays, and spheroid invasion assays after inhibition of ASPH with the small molecule inhibitor MO-I-1151. ASPH was also deactivated with the CRISPR/Cas9 system. A transcriptomic analysis was then performed with bulk RNA sequencing and differential gene expression was evaluated. Expression data were verified by quantitative PCR and immunoblotting. Results: Inhibition or abrogation of ASPH reduced proliferation of the cell lines and their migration and invasiveness. Among the genes with differential expression in more than one cell line, two members of the lymphocyte antigen 6 (Ly6) family, Ly6a and Ly6c1, were found. Their downregulation was confirmed at the protein level by immunoblotting, which also showed their reduction after ASPH inhibition in other mouse cell lines. Reduced production of the Ly6D and Ly6K proteins was shown after ASPH inhibition in human tumor cell lines. Conclusions: Since increased expression of Ly6 genes is associated with the development and progression of both mouse and human tumors, these results suggest a novel mechanism of ASPH oncogenicity and support the utility of ASPH as a target for cancer therapy.

Molecular profiling reveals potential targets in cholangiocarcinoma

BACKGROUND

Cholangiocarcinoma (CCA) is a devastating malignancy and has a very poor prognosis if tumors spread outside the liver. Understanding the molecular mechanisms underlying the CCA progression will likely yield therapeutic approaches toward treating this deadly disease.

AIM

To determine the molecular pathogenesis in CCA progression.

METHODS

In silico analysis, in vitro cell culture, CCA transgenic animals, histological, and molecular assays were adopted to determine the molecular pathogenesis.

RESULTS

The transcriptomic data of human CCA samples were retrieved from The Cancer Genome Atlas (TGCA, CHOL), European Bioinformatics Institute (EBI, GAD00001001076), and Gene Expression Omnibus (GEO, GSE107943) databases. Using Gene set enrichment analysis, the cell cycle and Notch related pathways were demonstrated to be significantly activated in CCA in TCGA and GEO datasets. We, through differentially expressed genes, found several cell cycle and notch associated genes were significantly up-regulated in cancer tissues when compared with the non-cancerous control samples. The associated genes, via quantitative real-time PCR and western blotting assays, were further examined in normal human cholangiocytes, CCA cell lines, mouse normal bile ducts, and mouse CCA tumors established by specifically depleting P53 and expressing KrasG12D mutation in the liver. Consistently, we validated that the cell cycle and Notch pathways are up-regulated in CCA cell lines and mouse CCA tumors. Interestingly, targeting cell cycle and notch pathways using small molecules also exhibited significant beneficial effects in controlling tumor malignancy. More importantly, we demonstrated that several cell cycle and Notch associated genes are significantly associated with poor overall survival and disease-free survival using the Log-Rank test.

CONCLUSION

In summary, our study comprehensively analyzed the gene expression pattern of CCA samples using publicly available datasets and identified the cell cycle and Notch pathways are potential therapeutic targets in this deadly disease.

Development and Characterization of Human Primary Cholangiocarcinoma Cell Lines

Cholangiocarcinoma (CCA) is the second most common primary liver tumor and is associated with late diagnosis, limited treatment options, and a 5-year survival rate of around 30%. CCA cell lines were first established in 1971, and since then, only 70 to 80 CCA cell lines have been established. These cell lines have been essential in basic and translational research to understand and identify novel mechanistic pathways, biomarkers, and disease-specific genes. Each CCA cell line has unique characteristics, reflecting a specific genotype, sex-related properties, and patient-related signatures, making them scientifically and commercially valuable. CCA cell lines are crucial in the use of novel technologies, such as three-dimensional organoid models, which help to model the tumor microenvironment and cell-to-cell crosstalk between tumor-neighboring cells. This review highlights crucial information on CCA cell lines, including: i) type of CCA (eg, intra- or extrahepatic), ii) isolation source (eg, primary tumor or xenograft), iii) chemical digestion method (eg, trypsin or collagenase), iv) cell-sorting method (colony isolation or removal of fibroblasts), v) maintenance-medium choice (eg, RPMI or Dulbecco's modified Eagle's medium), vi) cell morphology (eg, spindle or polygonal shape), and vii) doubling time of cells.

Dietary Soy Prevents Alcohol-Mediated Neurocognitive Dysfunction and Associated Impairments in Brain Insulin Pathway Signaling in an Adolescent Rat Model

BACKGROUND

Alcohol-related brain degeneration is linked to cognitive-motor deficits and impaired signaling through insulin/insulin-like growth factor type 1 (IGF-1)-Akt pathways that regulate cell survival, plasticity, metabolism, and homeostasis. In addition, ethanol inhibits Aspartyl-asparaginyl-β-hydroxylase (ASPH), a downstream target of insulin/IGF-1-Akt signaling and an activator of Notch networks. Previous studies have suggested that early treatment with insulin sensitizers or dietary soy could reduce or prevent the long-term adverse effects of chronic ethanol feeding.

OBJECTIVE

The goal of this study was to assess the effects of substituting soy isolate for casein to prevent or reduce ethanol's adverse effects on brain structure and function.

METHODS

Young adolescent male and female Long Evans were used in a 4-way model as follows: Control + Casein; Ethanol + Casein; Control + Soy; Ethanol + Soy; Control = 0% ethanol; Ethanol = 26% ethanol (caloric). Rats were fed isocaloric diets from 4 to 11 weeks of age. During the final experimental week, the Morris Water maze test was used to assess spatial learning (4 consecutive days), after which the brains were harvested to measure the temporal lobe expression of the total phospho-Akt pathway and downstream target proteins using multiplex bead-based enzyme-linked immunosorbent assays (ELISAs) and duplex ELISAs.

RESULTS

Ethanol inhibited spatial learning and reduced brain weight, insulin signaling through Akt, and the expression of ASPH when standard casein was provided as the protein source. The substitution of soy isolate for casein largely abrogated the adverse effects of chronic ethanol feeding. In contrast, Notch signaling protein expression was minimally altered by ethanol or soy isolate.

CONCLUSIONS

These novel findings suggest that the insulin sensitizer properties of soy isolate may prevent some of the adverse effects that chronic ethanol exposure has on neurobehavioral function and insulin-regulated metabolic pathways in adolescent brains.

Notch signaling in the pathogenesis, progression and identification of potential targets for cholangiocarcinoma (Review)

Cholangiocarcinoma (CCA) is an aggressive type of bile duct cancer that is characterized by a high mortality rate due to its late diagnosis and ineffective treatment. The aim of the present systematic review was to analyze the association between Notch signaling and CCA in terms of its pathogenesis, progression and potential treatment targets. Relevant information was gathered from the PubMed, ScienceDirect and Scopus databases using the search terms 'cholangiocarcinoma' AND 'Notch signaling'. Of the 90 articles identified, 28 fulfilled the eligibility criteria and were included in the analysis. It was concluded that overexpression/upregulation of Notch ligands, such as Jagged1 and Notch receptors (Notch1, Notch2 and Notch3), as well as upregulation of the upstream Notch signaling pathway, promoted CCA development and progression. In addition, downregulation of Notch1 signaling through several possible interventions appears to be a promising strategy for inhibition of CCA development and progression. Therefore, the Notch signaling pathway may be considered as a potential target for CCA control.

Aspartate β-Hydroxylase (ASPH) Expression in Acute Myeloid Leukemia: A Potential Novel Therapeutic Target

Background

Aspartate β-hydroxylase (ASPH) is an embryonic transmembrane protein aberrantly upregulated in cancer cells, associated with malignant transformation and, in some reports, with poor clinical prognosis.

Objective

To report the expression patterns of ASPH in acute myeloid leukemia (AML).

Methods

Cell surface expression of ASPH was measured via 8-color multiparameter flow cytometry in 41 AML patient samples (31 bone marrow, 10 blood) using fluorescein isothiocyanate (FITC)-conjugated anti-ASPH antibody, SNS-622. A mean fluorescent intensity (MFI) of 10 was used as a cutoff for ASPH surface expression positivity. Data regarding patient and disease characteristics were collected.

Results

ASPH surface expression was found on AML blasts in 16 samples (39%). Higher ASPH expression was seen in myeloblasts of African American patients (p=0.02), but no correlation was found between ASPH expression and other patient or disease characteristics. No association was found between ASPH status and CR rate (p=0.53), EFS (p=0.87), or OS (p=0.17).

Conclusions

ASPH is expressed on blasts in approximately 40% of AML cases, and may serve as a new therapeutically targetable leukemia-associated antigen.

Multi-organ metastasis as destination for breast cancer cells guided by biomechanical architecture

A majority of breast cancer patients die of widespread aggressive multidrug-resistant tumors. Aspartate β-hydroxylase (ASPH) is an α-ketoglutarate-dependent dioxygenase and oncofetal antigen involved in embryogenesis. To illustrate if ASPH could be targeted for metastatic breast cancer, embedded and on-top three-dimensional (3-D) cultures, 3-D invasion, mammosphere formation, immunofluorescence, immunohistochemistry, Western blot, co-IP and microarray were conducted. In vitro metastasis was developed to imitate how cancer cells invade basement membrane at the primary site, transendothelially migrate, consequently colonize and outgrow at distant sites. Orthotopic and experimental pulmonary metastatic (tail vein injection) murine models were established using stable breast cancer cell lines. Cox proportional hazards regression models and Kaplan-Meier plots were applied to assess clinical outcome of breast cancer patients. In adult non-cancerous breast tissue, ASPH is undetectable. Pathologically, ASPH expression re-emerged at ductal carcinoma in situ (DCIS), and enhanced with disease progression, from early-stage invasive ductal carcinoma (IDC) to late-stage carcinoma. ASPH at moderate to high levels contribute to aggressive molecular subtypes, early relapse or more frequent progression and metastases, whereas substantially shortened overall survival and disease-free survival of breast cancer patients. Through direct physical interactions with A disintegrin and metalloproteinase domain-containing protein (ADAM)-12/ADAM-15, ASPH could activate SRC cascade, thus upregulating downstream components attributed to multifaceted metastasis. ASPH-SRC axis initiated pro-invasive invadopodium formation causing breakdown/disorganization of extracellular matrix (ECM), simultaneously potentiated epithelial-mesenchymal transition (EMT), induced cancer stem cell markers (CD44 and EpCAM), enhanced mammosphere formation and intensified 3-dimentional invasion. Oncogenic SRC upregulated matrix metallopeptidases (MMPs) were assembled by invadopodia, acting as executive effectors for multi-step metastasis. ASPH-SRC signal guided multi-organ metastases (to lungs, liver, bone, spleen, lymph nodes, mesentery or colon) in immunocompromised mice. Malignant phenotypes induced by ASPH-SRC axis were reversed by the third-generation small molecule inhibitor (SMI) specifically against β-hydroxylase activity of ASPH in pre-clinical models of metastatic breast cancer. Collectively, ASPH could activate ADAMs-SRC-MMPs cascades to promote breast cancer tumor progression and metastasis. ASPH could direct invadopodium construction as a biomechanical sensor and pro-metastatic outlet. ASPH-mediated cancer progression could be specifically/efficiently subverted by SMIs of β-hydroxylase activity. Therefore, ASPH emerges as a therapeutic target for breast cancer.

Targeting Aspartate Beta-Hydroxylase with the Small Molecule Inhibitor MO-I-1182 Suppresses Cholangiocarcinoma Metastasis

BACKGROUND

Cholangiocarcinoma is a devastating disease with a 2% 5-year survival if the disease has spread outside the liver. The enzyme aspartate beta-hydroxylase (ASPH) has been demonstrated to be highly expressed in cholangiocarcinoma but not in normal bile ducts and found to stimulate tumor cell migration. In addition, it was found that targeting ASPH inhibits cholangiocarcinoma malignant progression. However, it is not clear whether targeting ASPH with the small molecule inhibitor MO-I-1182 suppresses cholangiocarcinoma metastasis. The current study aims to study the efficacy of MO-I-1182 in suppressing cholangiocarcinoma metastasis.

METHODS

The analysis was performed in vitro and in vivo with a preclinical animal model by using molecular and biochemical strategies to regulate ASPH expression and function.

RESULTS

Knockdown of ASPH substantially inhibited cell migration and invasion in two human cholangiocarcinoma cell lines. Targeting ASPH with a small molecule inhibitor suppressed cholangiocarcinoma progression. Molecular mechanism studies demonstrated that knockdown of ASPH subsequently suppressed protein levels of the matrix metalloproteinases. The ASPH knockdown experiments suggest that this enzyme may modulate cholangiocarcinoma metastasis by regulating matrix metalloproteinases expression. Furthermore, using an ASPH inhibitor in a rat cholangiocarcinoma intrahepatic model established with BED-Neu-CL#24 cholangiocarcinoma cells, it was found that targeting ASPH inhibited intrahepatic cholangiocarcinoma metastasis and downstream expression of the matrix metalloproteinases.

CONCLUSION

ASPH may modulate cholangiocarcinoma metastasis via matrix metalloproteinases expression. Taken together, targeting ASPH function may inhibit intrahepatic cholangiocarcinoma metastasis and improve survival.

Integrated omics and bioinformatics analyses for the toxic mechanism and material basis of Sophorae Tonkinensis radix et rhizome-induced hepatotoxicity

In traditional Chinese medicine theory, Sophorae Tonkinensis radix et rhizome (ST) has the effects of treating tonsillitis, sore throats, and heat-evil-induced diseases. However, the utilization of ST is relatively restricted owing to its toxicity. The previous studies have made some progress on the mechanism and material basis of ST-induced hepatotoxicity, but there is still no significant breakthrough. In this study, integrated omics and bioinformatics analyses were used to investigate the mechanism and material basis of ST-induced hepatotoxicity. Integrated omics were used to analyze the differentially expressed proteins and metabolites, based on which the significantly dysregulated pathways were analyzed by using MetaboAnalyst. Bioinformatics was applied to screen the toxic targets and material basis. Integrated omics revealed that 254 proteins and 42 metabolites were differentially expressed after the treatment with ST, out of which 7 proteins were significantly enriched in 3 pathways. Bioinformatics showed that 20 compounds may interfere with the expression of 7 toxic targets of ST. Multiple toxic targets of ST-induced hepatotoxicity were found in the study, whose dysregulation may trigger hepatocyte necrosis/apoptosis, liver metastasis, and liver cirrhosis. Multiple compounds may be the toxic material basis in response to these effects.

Small-molecule active pharmaceutical ingredients of approved cancer therapeutics inhibit human aspartate/asparagine-β-hydroxylase

Human aspartate/asparagine-β-hydroxylase (AspH) is a 2-oxoglutarate (2OG) dependent oxygenase that catalyses the hydroxylation of Asp/Asn-residues of epidermal growth factor-like domains (EGFDs). AspH is reported to be upregulated on the cell surface of invasive cancer cells in a manner distinguishing healthy from cancer cells. We report studies on the effect of small-molecule active pharmaceutical ingredients (APIs) of human cancer therapeutics on the catalytic activity of AspH using a high-throughput mass spectrometry (MS)-based inhibition assay. Human B-cell lymphoma-2 (Bcl-2)-protein inhibitors, including the (R)-enantiomer of the natural product gossypol, were observed to efficiently inhibit AspH, as does the antitumor antibiotic bleomycin A2. The results may help in the design of AspH inhibitors with the potential of increased selectivity compared to the previously identified Fe(II)-chelating or 2OG-competitive inhibitors. With regard to the clinical use of bleomycin A2 and of the Bcl-2 inhibitor venetoclax, the results suggest that possible side-effects mediated through the inhibition of AspH and other 2OG oxygenases should be considered.

Diverse molecular functions of aspartate β‑hydroxylase in cancer (Review)

Aspartate/asparagine β-hydroxylase (AspH) is a type II transmembrane protein that catalyzes the post-translational hydroxylation of definite aspartyl and asparaginyl residues in epidermal growth factor-like domains of substrates. In the last few decades, accumulating evidence has indicated that AspH expression is upregulated in numerous types of human malignant cancer and is associated with poor survival and prognosis. The AspH protein aggregates on the surface of tumor cells, which contributes to inducing tumor cell migration, infiltration and metastasis. However, small-molecule inhibitors targeting hydroxylase activity can markedly block these processes, both in vitro and in vivo. Immunization of tumor-bearing mice with a phage vaccine fused with the AspH protein can substantially delay tumor growth and progression. Additionally, AspH antigen-specific CD4⁺ and CD8⁺ T cells were identified in the spleen of tumor-bearing mice. Therefore, these agents may be used as novel strategies for cancer treatment. The present review summarizes the current progress on the underlying mechanisms of AspH expression in cancer development.

Aspartate β-hydroxylase targeting in castration-resistant prostate cancer modulates the NOTCH/HIF1α/GSK3β crosstalk

Castration-resistant prostate cancer (CRPC) is an incurable stage of the disease. A multivariate principal component analysis on CRPC in vitro models identified aspartyl (asparaginyl) β hydrolase (ASPH) as the most relevant molecule associated with the CRPC phenotype. ASPH is overexpressed in various malignant neoplasms and catalyzes the hydroxylation of aspartyl and asparaginyl residues in the epidermal growth factor (EGF)-like domains of proteins like NOTCH receptors and ligands, enhancing cell motility, invasion and metastatic spread. Bioinformatics analyses of ASPH in prostate cancer (PCa) and CRPC datasets indicate that ASPH gene alterations have prognostic value both in PCa and CRPC patients. In CRPC cells, inhibition of ASPH expression obtained through specific small interfering RNA or culturing cells in hypoxic conditions, reduced cell proliferation, invasion and cyclin D1 expression through modulation of the NOTCH signaling. ASPH and HIF1α crosstalk, within a hydroxylation-regulated signaling pathway, might be transiently driven by the oxidative stress evidenced inside CRPC cells. In addition, increased phosphorylation of GSK3β by ASPH silencing demonstrates that ASPH regulates GSK3β activity inhibiting its interactions with upstream kinases. These findings demonstrate the critical involvement of ASPH in CRPC development and may represent an attractive molecular target for therapy.

Notch signalling pathway in development of cholangiocarcinoma

Cholangiocarcinoma (CCA) comprises of extra-hepatic cholangiocarcinoma and intrahepatic cholangiocarcinoma cancers as a result of inflammation of epithelium cell lining of the bile duct. The incidence rate is increasing dramatically worldwide with highest rates in Eastern and South Asian regions. Major risk factors involve chronic damage and inflammation of bile duct epithelium from primary sclerosing cholangitis, chronic hepatitis virus infection, gallstones and liver fluke infection. Various genetic variants have also been identified and as CCA develops on the background of biliary inflammation, diverse range of molecular mechanisms are involved in its progression. Among these, the Notch signalling pathway acts as a major driver of cholangiocarcinogenesis and its components (receptors, ligands and downstream signalling molecules) represent a promising therapeutic targets. Gamma-Secretase Inhibitors have been recognized in inhibiting the Notch pathway efficiently. A comprehensive knowledge of the molecular pathways activated by the Notch signalling cascade as well as its functional crosstalk with other signalling pathways provide better approach in developing innovative therapies against CCA.

Aspartate β-hydroxylase as a target for cancer therapy

As metastasis is a major cause of death in cancer patients, new anti-metastatic strategies are needed to improve cancer therapy outcomes. Numerous pathways have been shown to contribute to migration and invasion of malignant tumors. Aspartate β-hydroxylase (ASPH) is a key player in the malignant transformation of solid tumors by enhancing cell proliferation, migration, and invasion. ASPH also promotes tumor growth by stimulation of angiogenesis and immunosuppression. These effects are mainly achieved via the activation of Notch and SRC signaling pathways. ASPH expression is upregulated by growth factors and hypoxia in different human tumors and its inactivation may have broad clinical impact. Therefore, small molecule inhibitors of ASPH enzymatic activity have been developed and their anti-metastatic effect confirmed in preclinical mouse models. ASPH can also be targeted by monoclonal antibodies and has also been used as a tumor-associated antigen to induce both cluster of differentiation (CD) 8+ and CD4+ T cells in mice. The PAN-301-1 vaccine against ASPH has already been tested in a phase 1 clinical trial in patients with prostate cancer. In summary, ASPH is a promising target for anti-tumor and anti-metastatic therapy based on inactivation of catalytic activity and/or immunotherapy.

Prometastatic secretome trafficking via exosomes initiates pancreatic cancer pulmonary metastasis

To demonstrate multifaceted contribution of aspartate β-hydroxylase (ASPH) to pancreatic ductal adenocarcinoma (PDAC) pathogenesis, in vitro metastasis assay and patient derived xenograft (PDX) murine models were established. ASPH propagates aggressive phenotypes characterized by enhanced epithelial-mesenchymal transition (EMT), 2-D/3-D invasion, extracellular matrix (ECM) degradation/remodeling, angiogenesis, stemness, transendothelial migration and metastatic colonization/outgrowth at distant sites. Mechanistically, ASPH activates Notch cascade through direct physical interactions with Notch1/JAGs and ADAMs. The ASPH-Notch axis enables prometastatic secretome trafficking via exosomes, subsequently initiates MMPs mediated ECM degradation/remodeling as an effector for invasiveness. Consequently, ASPH fosters primary tumor development and pulmonary metastasis in PDX models, which was blocked by a newly developed small molecule inhibitor (SMI) specifically against ASPH's β-hydroxylase activity. Clinically, ASPH is silenced in normal pancreas, progressively upregulated from pre-malignant lesions to invasive/advanced stage PDAC. Relatively high levels of ASPH-Notch network components independently/jointly predict curtailed overall survival (OS) in PDAC patients (log-rank test, Ps < 0.001; Cox proportional hazards regression, P < 0.001). Therefore, ASPH-Notch axis is essential for propagating multiple-steps of metastasis and predicts prognosis of PDAC patients. A specific SMI targeting ASPH offers a novel therapeutic approach to substantially retard PDAC development/progression.

Kinetic parameters of human aspartate/asparagine-β-hydroxylase suggest that it has a possible function in oxygen sensing

Human aspartate/asparagine-β-hydroxylase (AspH) is a 2-oxoglutarate (2OG)-dependent oxygenase that catalyzes the post-translational hydroxylation of Asp and Asn residues in epidermal growth factor-like domains (EGFDs). Despite its biomedical significance, studies on AspH have long been limited by a lack of assays for its isolated form. Recent structural work has revealed that AspH accepts substrates with a noncanonical EGFD disulfide connectivity (i.e. the Cys 1-2, 3-4, 5-6 disulfide pattern). We developed stable cyclic thioether analogues of the noncanonical EGFD AspH substrates to avoid disulfide shuffling. We monitored their hydroxylation by solid-phase extraction coupled to MS. The extent of recombinant AspH-catalyzed cyclic peptide hydroxylation appears to reflect levels of EGFD hydroxylation observed in vivo, which vary considerably. We applied the assay to determine the kinetic parameters of human AspH with respect to 2OG, Fe(II), l-ascorbic acid, and substrate and found that these parameters are in the typical ranges for 2OG oxygenases. Of note, a relatively high Km for O2 suggested that O2 availability may regulate AspH activity in a biologically relevant manner. We anticipate that the assay will enable the development of selective small-molecule inhibitors for AspH and other human 2OG oxygenases.

Aspartate/asparagine-β-hydroxylase: a high-throughput mass spectrometric assay for discovery of small molecule inhibitors

The human 2-oxoglutarate dependent oxygenase aspartate/asparagine-β-hydroxylase (AspH) catalyses the hydroxylation of Asp/Asn-residues in epidermal growth factor-like domains (EGFDs). AspH is upregulated on the surface of malign cancer cells; increased AspH levels correlate with tumour invasiveness. Due to a lack of efficient assays to monitor the activity of isolated AspH, there are few reports of studies aimed at identifying small-molecule AspH inhibitors. Recently, it was reported that AspH substrates have a non-canonical EGFD disulfide pattern. Here we report that a stable synthetic thioether mimic of AspH substrates can be employed in solid phase extraction mass spectrometry based high-throughput AspH inhibition assays which are of excellent robustness, as indicated by high Z'-factors and good signal-to-noise/background ratios. The AspH inhibition assay was applied to screen approximately 1500 bioactive small-molecules, including natural products and active pharmaceutical ingredients of approved human therapeutics. Potent AspH inhibitors were identified from both compound classes. Our AspH inhibition assay should enable the development of potent and selective small-molecule AspH inhibitors and contribute towards the development of safer inhibitors for other 2OG oxygenases, e.g. screens of the hypoxia-inducible factor prolyl-hydroxylase inhibitors revealed that vadadustat inhibits AspH with moderate potency.

Synthesis of Novel Pyridine-Carboxylates as Small-Molecule Inhibitors of Human Aspartate/Asparagine-β-Hydroxylase

The human 2‐oxoglutarate (2OG)‐dependent oxygenase aspartate/asparagine‐β‐hydroxylase (AspH) is a potential medicinal chemistry target for anticancer therapy. AspH is present on the cell surface of invasive cancer cells and accepts epidermal growth factor‐like domain (EGFD) substrates with a noncanonical (i. e., Cys 1–2, 3–4, 5–6) disulfide pattern. We report a concise synthesis of C‐3‐substituted derivatives of pyridine‐2,4‐dicarboxylic acid (2,4‐PDCA) as 2OG competitors for use in SAR studies on AspH inhibition. AspH inhibition was assayed by using a mass spectrometry‐based assay with a stable thioether analogue of a natural EGFD AspH substrate. Certain C‐3‐substituted 2,4‐PDCA derivatives were potent AspH inhibitors, manifesting selectivity over some, but not all, other tested human 2OG oxygenases. The results raise questions about the use of pyridine‐carboxylate‐related 2OG analogues as selective functional probes for specific 2OG oxygenases, and should aid in the development of AspH inhibitors suitable for in vivo use.

Aspartate-β-Hydroxylase: A Promising Target to Limit the Local Invasiveness of Colorectal Cancer

Colorectal cancer's (CRC) ability to invade local tissues and lymph nodes and generate distant metastases is the key for TNM classification. Aspartate-β-hydroxylase (ASPH), a transmembrane protein that catalyzes Notch receptors and ligand activation, is involved in tumor invasion. Because Notch is involved in gut homeostasis, it could be a target for CRC therapy. ASPH mRNA and protein expression, promoter methylation and gene copy numbers were evaluated using the TCGA and CPTAC human CRC datasets. Using digital pathology, ASPH was scored in the luminal area (LM), center tumor (CT) and invasive margin (IM) of 100 human CRCs. The effect of ASPH targeting on invasiveness and viability was tested by siRNA knockdown and small molecule inhibitors (SMI). Bioinformatics analysis showed increased expression of ASPH mRNA and protein in CRC, paired with a decreased methylation profile. ASPH genetic gain or amplification was frequent (56%), while deletion was rare (0.03%). Digital pathology analysis showed that ASPH exerted its pathological activity in the invasive margin of the tumor, affecting invasive front morphology, tumor budding and patients' overall survival. In vitro, ASPH targeting by siRNA or SMI reduced cell invasion and growth and caused Notch-1 downregulation. This study demonstrates that ASPH targeting by specific inhibitors could improve CRC treatment strategies.

Aspartate β-hydroxylase promotes pancreatic ductal adenocarcinoma metastasis through activation of SRC signaling pathway

BACKGROUND

Signaling pathways critical for embryonic development re-emerge in adult pancreas during tumorigenesis. Aspartate β-hydroxylase (ASPH) drives embryonic cell motility/invasion in pancreatic development/differentiation. We explored if dysregulated ASPH is critically involved in pancreatic cancer pathogenesis.

METHODS

To demonstrate if/how ASPH mediates malignant phenotypes, proliferation, migration, 2-D/3-D invasion, pancreatosphere formation, immunofluorescence, Western blot, co-immunoprecipitation, invadopodia formation/maturation/function, qRT-PCR, immunohistochemistry (IHC), and self-developed in vitro metastasis assays were performed. Patient-derived xenograft (PDX) models of human pancreatic ductal adenocarcinoma (PDAC) were established to illustrate in vivo antitumor effects of the third-generation small molecule inhibitor specifically against ASPH's β-hydroxylase activity. Prognostic values of ASPH network components were evaluated with Kaplan-Meier plots, log-rank tests, and Cox proportional hazards regression models.

RESULTS

ASPH renders pancreatic cancer cells more aggressive phenotypes characterized by epithelial-mesenchymal transition (EMT), 2-D/3-D invasion, invadopodia formation/function as demonstrated by extracellular matrix (ECM) degradation, stemness (cancer stem cell marker upregulation and pancreatosphere formation), transendothelial migration (mimicking intravasation/extravasation), and sphere formation (mimicking metastatic colonization/outgrowth at distant sites). Mechanistically, ASPH activates SRC cascade through direct physical interaction with ADAM12/ADAM15 independent of FAK. The ASPH-SRC axis enables invadopodia construction and initiates MMP-mediated ECM degradation/remodeling as executors for invasiveness. Pharmacologic inhibition of invadopodia attenuates in vitro metastasis. ASPH fosters primary tumor development and pulmonary metastasis in PDX models of PDAC, which is blocked by a leading compound specifically against ASPH enzymatic activity. ASPH is silenced in normal pancreas, progressively upregulated from pre-malignant lesions to invasive/advanced stages of PDAC. Expression profiling of ASPH-SRC network components independently/jointly predicts clinical outcome of PDAC patients. Compared to a negative-low level, a moderate-very high level of ASPH, ADAM12, activated SRC, and MMPs correlated with curtailed overall survival (OS) of pancreatic cancer patients (log-rank test, ps < 0.001). The more unfavorable molecules patients carry, the more deleterious prognosis is destinated. Patients with 0-2 (n = 4), 3-5 (n = 8), 6-8 (n = 24), and 9-12 (n = 73) unfavorable expression scores of the 5 molecules had median survival time of 55.4, 15.9, 9.7, and 5.0 months, respectively (p < 0.001).

CONCLUSION

Targeting the ASPH-SRC axis, which is essential for propagating multi-step PDAC metastasis, may specifically/substantially retard development/progression and thus improve prognosis of PDAC.

Anti-tumor activity of antibody drug conjugate targeting aspartate-β-hydroxylase in pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is an extremely aggressive malignancy with very limited treatment options. Antibody drug conjugates (ADCs) are promising cytotoxic agents capable of highly selective delivery. Aspartate-β-hydroxylase (ASPH) is a type II transmembrane protein highly expressed in PDACs (97.1%) but not normal pancreas. We investigated anti-tumor effects of an ADC guided by a human monoclonal antibody (SNS-622) against ASPH in human PDAC cell lines and derived subcutaneous (s.c.) xenograft as well as a patient-derived xenograft (PDX) murine model with spontaneous pulmonary metastasis. The cytotoxic effects exhibited by several candidate payloads linked to SNS-622 antibody targeting ASPH⁺ PDACs were analyzed. After i.v. administration of SNS-622-emtansine (DM1) ADC, the primary PDAC tumor growth and progression (number and size of pulmonary metastases) were determined. The PDAC cell lines, s.c. and PDX tumors treated with ADC were tested for cell proliferation, cytotoxicity and apoptosis by MTS and immunohistochemistry (IHC) assays. SNS-622-DM1 construct has demonstrated optimal anti-tumor effects in vitro. In the PDX model of human PDAC, SNS-622-DM1 ADC exerted substantially inhibitory effects on tumor growth and pulmonary metastasis through attenuating proliferation and promoting apoptosis.

Hydroxylase Activity of ASPH Promotes Hepatocellular Carcinoma Metastasis Through Epithelial-to-Mesenchymal Transition Pathway

Over-expression of aspartyl (asparagynal)-β-hydroxylase (ASPH) contributes to hepatocellular carcinoma (HCC) invasiveness, but the role of ASPH hydroxylase activity in this process remains to be defined. As such, the current study investigated the role of ASPH hydroxylase activity in downstream signalling of HCC tumorgenesis and, specifically, metastasis development. Over-expression of wild-type ASPH, but not a hydroxylase mutant, promoted HCC cell migration in vitro, as well as intrahepatic and distant metastases in vivo. The enhanced migration and epithelial to mesenchymal transition (EMT) activation was notably absent in response to hydroxylase activity blockade. Vimentin, a regulator of EMT, interacted with ASPH and likely mediated the effect of ASPH hydroxylase activity with cell migration. The enhanced hydroxylase activity in tumor tissues predicted worse prognoses of HCC patients. Collectively, the hydroxylase activity of ASPH affected HCC metastasis through interacting with vimentin and regulating EMT. As such, ASPH might be a promising therapeutic target of HCC.

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Over-expression of ASPH promoted HCC intrahepatic and distant metastases in vivo.

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ASPH interacts with vimentin to promote HCC cell migration.

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Enhanced hydroxylase activity in tumor predicted worse prognoses of HCC patients.

Hepatocellular carcinoma has aggressive invasiveness and high metastatic rate. The reason for metastasis is largely unknown and the effective treatment is still lacking. Although over-expression of ASPH has been demonstrated to enhance hepatocellular carcinoma invasiveness, whether its hydroxylase activity is necessary remains uncharacterized. Here, we found the hydroxylase activity was critical to promote hepatocellular carcinoma invasiveness in vitro and metastasis in vivo, and associated with post-surgery survival. ASPH hydroxylase activity play an important role in epithelial-to-mesenchymal transition through interacting with vimentin. Our findings imply that ASPH antagonists might be promising in developing novel therapy.

Aspartate beta-hydroxylase promotes cholangiocarcinoma progression by modulating RB1 phosphorylation

Cholangiocarcinoma (CCA) is a highly lethal and aggressive disease. Recently, IDH1/2 mutations have been identified in approximately 20% of CCAs which suggests an involvement of 2-oxoglutarate (2-OG) -dependent dioxygenases in oncogenesis. We investigated if the 2-OG dependent dioxygenase, aspartate beta-hydroxylase (ASPH) was important in tumor development and growth. Immunoassays were used to clarify how ASPH modulates CCA progression by promoting phosphorylation of the retinoblastoma protein (RB1). A xenograft model was employed to determine the role of ASPH on CCA growth. Knockdown of ASPH expression inhibited CCA development and growth by reducing RB1 phosphorylation. Expression of ASPH promoted direct protein interaction between RB1, cyclin-dependent kinases, and cyclins. Treatment with 2-OG-dependent dioxygenase and ASPH inhibitors suppressed the interaction between RB1 and CDK4 as well as RB1 phosphorylation. Knockdown of ASPH expression inhibited CCA progression and RB1 phosphorylation in vivo and they were found to be highly expressed in human CCAs. Knockdown of ASPH expression altered CCA development by modulating RB1 phosphorylation, as one of the major factors regulating the growth of these tumors.

Molecular Mechanisms Driving Cholangiocarcinoma Invasiveness: An Overview

The acquisition of invasive functions by tumor cells is a first and crucial step toward the development of metastasis, which nowadays represents the main cause of cancer-related death. Cholangiocarcinoma (CCA), a primary liver cancer originating from the biliary epithelium, typically develops intrahepatic or lymph node metastases at early stages, thus preventing the majority of patients from undergoing curative treatments, consistent with their very poor prognosis. As in most carcinomas, CCA cells gradually adopt a motile, mesenchymal-like phenotype, enabling them to cross the basement membrane, detach from the primary tumor, and invade the surrounding stroma. Unfortunately, little is known about the molecular mechanisms that synergistically orchestrate this proinvasive phenotypic switch. Autocrine and paracrine signals (cyto/chemokines, growth factors, and morphogens) permeating the tumor microenvironment undoubtedly play a prominent role in this context. Moreover, a number of recently identified signaling systems are currently drawing attention as putative mechanistic determinants of CCA cell invasion. They encompass transcription factors, protein kinases and phosphatases, ubiquitin ligases, adaptor proteins, and miRNAs, whose aberrant expression may result from either stochastic mutations or the abnormal activation of upstream pro-oncogenic pathways. Herein we sought to summarize the most relevant molecules in this field and to discuss their mechanism of action and potential prognostic relevance in CCA. Hopefully, a deeper knowledge of the molecular determinants of CCA invasiveness will help to identify clinically useful biomarkers and novel druggable targets, with the ultimate goal to develop innovative approaches to the management of this devastating malignancy.

Lambda phage-based vaccine induces antitumor immunity in hepatocellular carcinoma

BACKGROUND AND AIMS

Hepatocellular carcinoma (HCC) is a difficult to treat tumor with a poor prognosis. Aspartate β-hydroxylase (ASPH) is a highly conserved enzyme overexpressed on the cell surface of both murine and human HCC cells.

METHODS

We evaluated therapeutic effects of nanoparticle lambda (λ) phage vaccine constructs against ASPH expressing murine liver tumors. Mice were immunized before and after subcutaneous implantation of a syngeneic BNL HCC cell line. Antitumor actively was assessed by generation of antigen specific cellular immune responses and the identification of tumor infiltrating lymphocytes.

RESULTS

Prophylactic and therapeutic immunization significantly delayed HCC growth and progression. ASPH-antigen specific CD4+ and CD8+ lymphocytes were identified in the spleen of tumor bearing mice and cytotoxicity was directed against ASPH expressing BNL HCC cells. Furthermore, vaccination generated antigen specific Th1 and Th2 cytokine secretion by immune cells. There was widespread necrosis with infiltration of CD3+ and CD8+ T cells in HCC tumors of λ phage vaccinated mice compared to controls. Moreover, further confirmation of anti-tumor effects on ASPH expressing tumor cell growth were obtained in another murine syngeneic vaccine model with pulmonary metastases.

CONCLUSIONS

These observations suggest that ASPH may serve as a highly antigenic target for immunotherapy.

Ethanol-Induced White Matter Atrophy Is Associated with Impaired Expression of Aspartyl-Asparaginyl-β-Hydroxylase (ASPH) and Notch Signaling in an Experimental Rat Model

Alcohol-induced white matter (WM) degeneration is linked to cognitive-motor deficits and impairs insulin/insulin-like growth factor (IGF) and Notch networks regulating oligodendrocyte function. Ethanol downregulates Aspartyl-Asparaginyl-β-Hydroxylase (ASPH) which drives Notch. These experiments determined if alcohol-related WM degeneration was linked to inhibition of ASPH and Notch. Adult Long Evans rats were fed for 3, 6 or 8 weeks with liquid diets containing 26% ethanol (caloric) and in the last two weeks prior to each endpoint they were binged with 2 g/kg ethanol, 3×/week. Controls were studied in parallel. Histological sections of the frontal lobe and cerebellar vermis were used for image analysis. Frontal WM proteins were used for Western blotting and duplex ELISAs. The ethanol exposures caused progressive reductions in frontal and cerebellar WM. Ethanol-mediated frontal WM atrophy was associated with reduced expression of ASPH, Jagged 1, HES-1, and HIF-1α. These findings link ethanol-induced WM atrophy to inhibition of ASPH expression and signaling through Notch networks, including HIF-1α.

Role of the Notch signaling in cholangiocarcinoma

INTRODUCTION

Cholangiocarcinoma (CCA) is an emerging cancer entity of the liver, associated with poor outcome and characterized by resistance to conventional chemotherapeutic treatments. In the last decade, many signaling pathways associated with CCA development and progression have been identified and are currently under intense investigation. Cumulating evidence indicates that the Notch cascade, a highly-conserved pathway in most multicellular organisms, is a critical player both in liver malignant transformation and tumor aggressiveness, thus representing a potential therapeutic target in this pernicious disease. Areas covered: In the present review article, we comprehensively summarize and critically discuss the current knowledge on the Notch pathway, its specific and key roles in cholangiocarcinogenesis, the treatment strategies aimed at suppressing this signaling cascade in cancer, and the encouraging results coming from preclinical trials. Expert opinion: The Notch pathway represents a major driver of carcinogenesis and a promising therapeutic target in human CCA. A better understanding of the molecular mechanisms triggered by the Notch pathway as well as its functional crosstalk with other signaling cascade will be highly helpful for the design of innovative therapies against human CCA.

Role of Notch signaling pathway in pancreatic cancer

Pancreatic cancer (PC) is one of the highly aggressive malignancies in the United States. It has been shown that multiple signaling pathways are involved in the pathogenesis of PC, such as JNK, PI3K/AKT, Rho GTPase, Hedgehog (Hh) and Skp2. In recent years, accumulated evidence has demonstrated that Notch signaling pathway plays critical roles in the development and progression of PC. Therefore, in this review we discuss the recent literature regarding the function and regulation of Notch in the pathogenesis of PC. Moreover, we describe that Notch signaling pathway could be down-regulated by its inhibitors or natural compounds, which could be a novel approach for the treatment of PC patients.

Aspartate-β-hydroxylase (ASPH): A potential therapeutic target in human malignant gliomas

BACKGROUND

Despite therapeutic advances, survival with glioblastoma multiforme (GBM) remains below 15 months from diagnosis due to GBM's highly infiltrative nature which precludes complete surgical resection. Patient outcomes could potentially be improved by targeting genes and pathways that drive neoplastic cell motility and invasiveness, including hypoxia-inducible factor-1 (HIF-1α), NOTCH, and aspartate-β-hydroxylase (ASPH).

METHODS

Human astrocytoma biopsy specimens (n = 37), WHO Grades II-IV, were analyzed for levels and distributions of ASPH and HIF-1α immunoreactivity by immunohistochemical staining, and ASPH, Notch, JAG, HES1, HEY1 and HIF1α mRNA expression by quantigene multiplex analysis. The effects of small molecule inhibitors on ASPH's catalytic activity, cell viability and directional motility were examined in vitro in established GBM cell lines and primary tumor cells from an invasive mouse model of GBM.

RESULTS

The highest grade astrocytoma, i.e. GBM was associated with the highest levels of ASPH and HIF1α, and both proteins were more abundantly distributed in hypoxic compared with normoxic regions of tumor. Furthermore, mining of the TCGA database revealed higher levels of ASPH expression in the mesenchymal subtype of GBM, which is associated with more aggressive and invasive behavior. In contrast, lower grade astrocytomas had low expression levels of ASPH and HIF1α. In vitro experiments demonstrated that small molecule inhibitors targeting ASPH's catalytic activity significantly reduced GBM viability and directional motility. Similar effects occurred in GBM cells that were transduced with a lentiviral sh-ASPH construct.

CONCLUSION

This study demonstrates that increased ASPH expression could serve as a prognostic biomarker of gliomas and may assist in assigning tumor grade when biopsy specimens are scant. In addition, the findings suggest that GBM treatment strategies could be made more effective by including small molecule inhibitors of ASPH.