PARP1 activation increases expression of modified tumor suppressors and pathways underlying development of aggressive hepatoblastoma

Valanejad, Leila; Cast, Ashley; Wright, Mary Jo; Bissig, Karl‐Dimiter; Karns, Rebekah; Weirauch, Matthew T.; Timchenko, Nikolai A.

doi:10.1038/s42003-018-0077-8

Cited by 30 publications

(76 citation statements)

References 52 publications

(92 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Protein extracts were isolated from available 10 HBL and 5 NTCL samples as previously described. 27,28 This assay was performed in duplicate, where proteins (50 µg) were loaded onto a 4% to 20% gradient gel (BioRad, USA) and transferred to a nitrocellulose membrane (BioRad). The membranes were probed with anti-NNMT (OTI3D8; Abcam) and anti-beta-actin (ab8227; Abcam) antibodies.…”

Section: Methodsmentioning

confidence: 99%

Hepatoblastomas exhibit markedNNMTdownregulation driven by promoter DNA hypermethylation

et al. 2020

Self Cite

View full text Add to dashboard Cite

Hepatoblastomas exhibit the lowest mutational burden among pediatric tumors. We previously showed that epigenetic disruption is crucial for hepatoblastoma carcinogenesis. Our data revealed hypermethylation of nicotinamide N-methyltransferase, a highly expressed gene in adipocytes and hepatocytes. The expression pattern and the role of nicotinamide N-methyltransferase in pediatric liver tumors have not yet been explored, and this study aimed to evaluate the effect of nicotinamide N-methyltransferase hypermethylation in hepatoblastomas. We evaluated 45 hepatoblastomas and 26 non-tumoral liver samples. We examined in hepatoblastomas if the observed nicotinamide N-methyltransferase promoter hypermethylation could lead to dysregulation of expression by measuring mRNA and protein levels by real-time quantitative polymerase chain reaction, immunohistochemistry, and Western blot assays. The potential impact of nicotinamide N-methyltransferase changes was evaluated on the metabolic profile by high-resolution magic angle spinning nuclear magnetic resonance spectroscopy. Significant nicotinamide N-methyltransferase downregulation was revealed in hepatoblastomas, with two orders of magnitude lower nicotinamide N-methyltransferase expression in tumor samples and hepatoblastoma cell lines than in hepatocellular carcinoma cell lines. A specific TSS1500 CpG site (cg02094283) of nicotinamide N-methyltransferase was hypermethylated in tumors, with an inverse correlation between its methylation level and nicotinamide N-methyltransferase expression. A marked global reduction of the nicotinamide N-methyltransferase protein was validated in tumors, with strong correlation between gene and protein expression. Of note, higher nicotinamide N-methyltransferase expression was statistically associated with late hepatoblastoma diagnosis, a known clinical variable of worse prognosis. In addition, untargeted metabolomics analysis detected aberrant lipid metabolism in hepatoblastomas. Data presented here showed the first evidence that nicotinamide N-methyltransferase reduction occurs in hepatoblastomas, providing further support that the nicotinamide N-methyltransferase downregulation is a wide phenomenon in liver cancer. Furthermore, this study unraveled the role of DNA methylation in the regulation of nicotinamide N-methyltransferase expression in hepatoblastomas, in addition to evaluate the potential effect of nicotinamide N-methyltransferase reduction in the metabolism of these tumors. These preliminary findings also suggested that nicotinamide N-methyltransferase level may be a potential prognostic biomarker for hepatoblastoma.

show abstract

Section: Methodsmentioning

confidence: 99%

Hepatoblastomas exhibit markedNNMTdownregulation driven by promoter DNA hypermethylation

et al. 2020

Self Cite

View full text Add to dashboard Cite

show abstract

“…Increased expression of EPHA8 may be a prognostic marker for epithelial ovarian cancer [28]. The effect of increased expression of PARP1 in HCC has also been previously reported [29,30]. PARP1 has been shown to physically interact with hepatitis B virus X protein and to inhibit the activity of the DNA repair complex at damaged DNA sites, resulting in hepatocarcinogenesis [31].…”

Section: Discussionmentioning

confidence: 97%

Bioinformatics Analysis Identifies Protein Tyrosine Kinase 7 (PTK7) as a Potential Prognostic and Therapeutic Biomarker in Stages I to IV Hepatocellular Carcinoma

Zou

Liang

et al. 2019

Med Sci Monit

View full text Add to dashboard Cite

Background: Worldwide, hepatocellular carcinoma (HCC) accounts for 80-90% of all cases of primary liver cancer, and is one of the ten most common malignancies. This study used bioinformatics analysis to identify genes associated with patient outcome in stages I-IV HCC and the gene pathways that distinguished between normal liver and liver cells and HCC and human HCC cell lines. Material/Methods: Target genes were defined as those that had marketed drugs or drugs under development targeting a specific gene and acquired from the Clarivate Analytics Integrity Database. Differential expression gene analysis, co-expression network analysis, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis, survival analysis and receiver operating characteristic (ROC) curve analysis were used to explore the similarities and differences in gene expression profiles, functional associations, and survival in stage I-IV HCC. Normal liver cells (HL-7702) and HCC cell lines (HepaRG, HepG2, SK-Hep1, and Huh7) were studied using Western blot and quantitative reverse transcription PCR (RT-qPCR). Results: Hierarchical gene clustering identified target genes that distinguished between HCC and normal liver tissue. For stages I-IV HCC, there were seven commonly upregulated target genes EPHB1, LTK, NTRK2, PTK7, TBK1, TIE1, and TLR3, which were mainly involved in immune and signaling transduction pathways. PTK7 was highly expressed in stage I-IV HCC and was an independent prognostic marker for reduced overall survival (OS). Conclusions: Bioinformatics analysis, combined with patient survival analysis, identified PTK7 gene expression as a potential therapeutic target and prognostic biomarker for all stages of HCC.

show abstract

“…PARPs are multifunctional enzymes involved in epigenetic modifications, signal transduction, stress sensing, and DNA repair ( 60 – 62 ). Interestingly, in a context of aggressive HB, PARP1 was recently shown to be aberrantly activated, promoting expression of nonfunctional tumor suppressor proteins ( 63 ). Herein, we demonstrated decreases in PARP1 and PARP2 expression in HB cells both at mRNA and protein level after CQ treatment.…”

Section: Discussionmentioning

confidence: 99%

Chloroquine Triggers Cell Death and Inhibits PARPs in Cell Models of Aggressive Hepatoblastoma

Eloranta

Cairo²,

Liljeström

et al. 2020

Front. Oncol.

View full text Add to dashboard Cite

Background: Hepatoblastoma (HB) is the most common pediatric liver malignancy. Despite advances in chemotherapeutic regimens and surgical techniques, the survival of patients with advanced HB remains poor, underscoring the need for new therapeutic approaches. Chloroquine (CQ), a drug used to treat malaria and rheumatologic diseases, has been shown to inhibit the growth and survival of various cancer types. We examined the antineoplastic activity of CQ in cell models of aggressive HB. Methods: Seven human HB cell models, all derived from chemoresistant tumors, were cultured as spheroids in the presence of relevant concentrations of CQ. Morphology, viability, and induction of apoptosis were assessed after 48 and 96 h of CQ treatment. Metabolomic analysis and RT-qPCR based Death Pathway Finder array were used to elucidate the molecular mechanisms underlying the CQ effect in a 2-dimensional cell culture format. Quantitative western blotting was performed to validate findings at the protein level. Results: CQ had a significant dose and time dependent effect on HB cell viability both in spheroids and in 2-dimensional cell cultures. Following CQ treatment HB spheroids exhibited increased caspase 3/7 activity indicating the induction of apoptotic cell death. Metabolomic profiling demonstrated significant decreases in the concentrations of NAD + and aspartate in CQ treated cells. In further investigations, oxidation of NAD + decreased as consequence of CQ treatment and NAD + /NADH balance shifted toward NADH. Aspartate supplementation rescued cells from CQ induced cell death. Additionally, downregulated expression of PARP1 and PARP2 was observed. Conclusions: CQ treatment inhibits cell survival in cell models of aggressive HB, presumably by perturbing NAD + levels, impairing aspartate bioavailability, and inhibiting PARP expression. CQ thus holds potential as a new agent in the management of HB.

show abstract

PARP1 activation increases expression of modified tumor suppressors and pathways underlying development of aggressive hepatoblastoma

Cited by 30 publications

References 52 publications

Hepatoblastomas exhibit markedNNMTdownregulation driven by promoter DNA hypermethylation

Hepatoblastomas exhibit markedNNMTdownregulation driven by promoter DNA hypermethylation

Bioinformatics Analysis Identifies Protein Tyrosine Kinase 7 (PTK7) as a Potential Prognostic and Therapeutic Biomarker in Stages I to IV Hepatocellular Carcinoma

Chloroquine Triggers Cell Death and Inhibits PARPs in Cell Models of Aggressive Hepatoblastoma

Contact Info

Product

Resources

About