Detection of γ-OHPdG in Circulating Tumor Cells of Patients With Hepatocellular Carcinoma as a Potential Prognostic Biomarker of Recurrence.

Background And Aims: Blood-based biomarkers for hepatocellular carcinoma (HCC) and its recurrence are lacking. We previously showed that hepatic γ-hydroxy-1, -propano-2'-deoxyguanosine (γ-OHPdG), an endogenous DNA adduct derived from acrolein by lipid peroxidation, increased during hepatocarcinogenesis. Additionally, higher hepatic γ-OHPdG from HCC patients after surgery were strongly associated with poor survival ( < .

Adamantyl Isothiocyanates as Mutant p53 Rescuing Agents and Their Structure-Activity Relationships.

Mutant p53 rescue by small molecules is a promising therapeutic strategy. In this structure-activity relationship study, we examined a series of adamantyl isothiocyanates (Ad-ITCs) to discover novel agents as therapeutics by targeting mutant p53. We demonstrated that the alkyl chain connecting adamantane and ITC is a crucial determinant for Ad-ITC inhibitory potency.

Theaphenon E prevents fatty liver disease and increases CD4+ T cell survival in mice fed a high-fat diet.

Background & Aims: Obesity is a major cause of non-alcoholic fatty liver disease (NAFLD). NAFLD is an epidemic affecting nearly 34% of the adult population in the US. As a chronic inflammatory disease, NAFLD influences the immune system by dysregulating T-cell activity.

p53 mutant-type in human prostate cancer cells determines the sensitivity to phenethyl isothiocyanate induced growth inhibition.

Background: We reported previously that phenethyl isothiocyanate (PEITC), a dietary compound, can reactivate p53 mutant in vitro and in SK-BR-3 (p53) breast xenograft model resulting in tumor inhibition. Because of the diversity of human cancers with p53 mutations, these findings raise important questions whether this mechanism operates in different cancer types with same or different p53 mutations. In this study, we investigated whether PEITC recuses mutant p53 in prostate cancer cells harboring different types of p53 mutants, structural and contact, in vitro and in vivo.

Oxidative stress and hepatocarcinogenesis.

Hepatocellular carcinoma (HCC) is the second leading cause of cancer-related deaths worldwide. There are two major challenges for HCC, the first being that early detection is generally not applicable, and secondly, it is usually fatal within several months after diagnosis. HCC is an inflammation-induced cancer.

Prevention of Lipid Peroxidation-derived Cyclic DNA Adduct and Mutation in High-Fat Diet-induced Hepatocarcinogenesis by Theaphenon E.

Obesity is associated with cancer risk and its link with liver cancer is particularly strong. Obesity causes non-alcoholic fatty liver disease (NAFLD) that could progress to hepatocellular carcinoma (HCC). Chronic inflammation likely plays a key role.

Monoclonal Antibodies for the Detection of a Specific Cyclic DNA Adduct Derived from ω-6 Polyunsaturated Fatty Acids.

Lipid peroxidation of polyunsaturated fatty acids (PUFAs) is an endogenous source of α,β-unsaturated aldehydes that react with DNA producing a variety of cyclic adducts. The mutagenic cyclic adducts, specifically those derived from oxidation of ω-6 PUFAs, may contribute to the cancer promoting activities associated with ω-6 PUFAs. ( E)-4-Hydroxy-2-nonenal (HNE) is a unique product of ω-6 PUFAs oxidation.

Detection of a lipid peroxidation-induced DNA adduct across liver disease stages.

Background: Oxidative stress and chronic inflammation can increase cellular levels of reactive oxygen species and lipid peroxidation (LPO) when associated with the pathogenesis of hepatocellular carcinoma (HCC), which can develop following the progression of steatosis, fibrosis and cirrhosis. Using a monoclonal antibody for cyclic γ-hydroxy-1, -propanodeoxyguanosine (γ-OHPdG), a promutagenic DNA adduct formed endogenously by LPO, we examined its formation across liver disease stages to understand it's potential role in HCC development.

Methods: Formalin-fixed paraffin embedded (FFPE) liver tissue samples from 49 patients representing normal, steatosis, fibrosis, cirrhosis and HCC were stained for γ-OHPdG and 8-hydroxydeoxyguanosine (8-oxo-dG), an oxidative damage biomarker.

Isothiocyanates suppress the invasion and metastasis of tumors by targeting FAK/MMP-9 activity.

Isothiocyanates, which are present as glucosinolate precursors in cruciferous vegetables, have strong activity against various cancers. Here, we compared the anti-metastatic effects of isothiocyanates (benzyl isothiocyanate (BITC), phenethyl isothiocyanate (PEITC), and sulforaphane (SFN)) by examining how they regulate MMP-9 expression. Isothiocyanates, particularly PEITC, suppressed 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced MMP-9 activity and invasion in various cancer cell lines.

An endogenous DNA adduct as a prognostic biomarker for hepatocarcinogenesis and its prevention by Theaphenon E in mice.

Unlabelled: Hepatocellular carcinoma (HCC) is the third leading cause of cancer-related deaths worldwide, mainly because of its poor prognosis. A valid mechanism-based prognostic biomarker is urgently needed. γ-hydroxy-1,N -propanodeoxyguanosine (γ-OHPdG) is an endogenously formed mutagenic DNA adduct derived from lipid peroxidation.

Nucleotide excision repair deficiency increases levels of acrolein-derived cyclic DNA adduct and sensitizes cells to apoptosis induced by docosahexaenoic acid and acrolein.

The acrolein derived cyclic 1,N(2)-propanodeoxyguanosine adduct (Acr-dG), formed primarily from ω-3 polyunsaturated fatty acids such as docosahexaenoic acid (DHA) under oxidative conditions, while proven to be mutagenic, is potentially involved in DHA-induced apoptosis. The latter may contribute to the chemopreventive effects of DHA. Previous studies have shown that the levels of Acr-dG are correlated with apoptosis induction in HT29 cells treated with DHA.

Aldo-keto reductase 1B10 protects human colon cells from DNA damage induced by electrophilic carbonyl compounds.

Electrophilic carbonyl compounds are highly cytotoxic and genotoxic. Aldo-keto reductase 1B10 (AKR1B10) is an enzyme catalyzing reduction of carbonyl compounds to less toxic alcoholic forms. This study presents novel evidence that AKR1B10 protects colon cells from DNA damage induced by electrophilic carbonyl compounds.

In vivo detection of a novel endogenous etheno-DNA adduct derived from arachidonic acid and the effects of antioxidants on its formation.

Previous studies showed that 7-(1',2'-dihydroxyheptyl)-substituted etheno DNA adducts are products of reactions with the epoxide of (E)-4-hydroxy-2-nonenal, an oxidation product of ω-6 polyunsaturated fatty acids (PUFAs). In this work, we report the detection of 7-(1',2'-dihydroxyheptyl)-1,N(6)-ethenodeoxyadenosine (DHHedA) in rodent and human tissues by two independent methods: a (32)P-postlabeling/HPLC method and an isotope dilution liquid chromatography-electrospray ionization-tandem mass spectrometry method, demonstrating for the first time that DHHedA is a background DNA lesion in vivo. We showed that DHHedA can be formed upon incubation of arachidonic acid with deoxyadenosine, supporting the notion that ω-6 PUFAs are the endogenous source of DHHedA formation.

A Click Chemistry Approach to Identify Protein Targets of Cancer Chemopreventive Phenethyl Isothiocyanate.

Here we report the identification of protein targets of chemopreventive phenethyl isothiocyanate (PEITC) via "click" chemistry in the A549 human lung cancer cell line, using a novel alkyne-tagged PEITC which was also found to show potent anticancer activity.

Repair kinetics of acrolein- and (E)-4-hydroxy-2-nonenal-derived DNA adducts in human colon cell extracts.

ω-3 and ω-6 polyunsaturated fatty acids (PUFAs) play a role in the pathogenesis of colon cancer. Upon oxidation, PUFAs generate α,β-unsaturated aldehydes or enals, such as acrolein (Acr) and (E)-4-hydroxy-2-nonenal (HNE), which can form cyclic adducts of deoxyguanosine (Acr-dG and HNE-dG, respectively) in DNA. Both Acr-dG and HNE-dG adducts have been detected in human and animal tissues and are potentially mutagenic and carcinogenic.

Detection of acrolein-derived cyclic DNA adducts in human cells by monoclonal antibodies.

Acrolein (Acr) is a ubiquitous environmental pollutant found in cigarette smoke and automobile exhaust. It can also be produced endogenously by oxidation of polyunsaturated fatty acids. The Acr-derived 1,N(2)-propanodeoxyguanosine (Acr-dG) adducts in DNA are mutagenic lesions that are potentially involved in human cancers.

Effect of CpG methylation at different sequence context on acrolein- and BPDE-DNA binding and mutagenesis.

Acrolein (Acr), an α,β-unsaturated aldehyde, is abundant in tobacco smoke and cooking and exhaust fumes. Acr induces mutagenic α- and γ- hydroxy-1,N(2)-cyclic propano-deoxyguanosine adducts in normal human bronchial epithelial cells. Our earlier work has found that Acr-induced DNA damage preferentially occurs at lung cancer p53 mutational hotspots that contain CpG sites and that methylation at CpG sites enhances Acr-DNA binding at these sites.

High-throughput, quantitative analysis of acrolein-derived DNA adducts in human oral cells by immunohistochemistry.

Acrolein (Acr) is a ubiquitous environmental pollutant as well as an endogenous compound. Acrolein-derived 1,N(2)-propanodeoxyguanosines (Acr-dG) are exocyclic DNA adducts formed following exposure to cigarette smoke or from lipid peroxidation. Acr-dG is mutagenic and potentially carcinogenic and may represent a useful biomarker for the early detection of cancers related to smoking or other oxidative conditions, such as chronic inflammation.

Regioselective formation of acrolein-derived cyclic 1,N(2)-propanodeoxyguanosine adducts mediated by amino acids, proteins, and cell lysates.

Acrolein (Acr) is a major component in cigarette smoke and a ubiquitous environmental pollutant. It is also formed as a product of lipid peroxidation. Following ring closure via the Michael addition, Acr modifies deoxyguanosine (dG) in DNA by forming cyclic 1,N(2)-propanodeoxyguanosine adducts (OHPdG).

A six-month crossover chemoprevention clinical trial of tea in smokers and non-smokers: methodological issues in a feasibility study.

Background: Chemoprevention crossover trials of tea can be more efficient than parallel designs but the attrition and compliance rates with such trials are unknown.

Methods: Attrition (dropouts) and compliance with treatment were assessed in a 25-week randomized, placebo controlled, crossover, feasibility clinical trial of four tea treatments to investigate the effect of tea on oral cancer biomarkers. Each treatment lasted 4 weeks with 2 weeks of washout in between.

Proteomic analysis of covalent modifications of tubulins by isothiocyanates.

Although isothiocyanates (ITC), which are found in cruciferous vegetables, have been shown to inhibit carcinogenesis in animal models and induce apoptosis and cell cycle arrest in tumor cells, the biochemical mechanisms of cell growth inhibition by these compounds are not fully understood. Studies have reported that ITC binding to intracellular proteins may be an important event for initiating apoptosis. Specific protein target(s) and molecular mechanisms for ITC have been investigated in human lung cancer A549 cells using proteomic tools.

Effect of carcinogenic acrolein on DNA repair and mutagenic susceptibility.

Acrolein (Acr), a ubiquitous environmental contaminant, is a human carcinogen. Acr can react with DNA to form mutagenic α- and γ-hydroxy-1, N(2)-cyclic propano-2'-deoxyguanosine adducts (α-OH-Acr-dG and γ-OH-Acr-dG). We demonstrate here that Acr-dG adducts can be efficiently repaired by the nucleotide excision repair (NER) pathway in normal human bronchial epithelia (NHBE) and lung fibroblasts (NHLF).

Identification of potential protein targets of isothiocyanates by proteomics.

Isothiocyanates (ITCs), such as phenethyl isothiocyanate (PEITC) and sulforaphane (SFN), are effective cancer chemopreventive compounds. It is believed that the major mechanism for the cancer preventive activity of ITCs is through the induction of cell cycle arrest and apoptosis. However, the upstream molecular targets of ITCs have been underexplored until recently.

Sulforaphane prevents microcystin-LR-induced oxidative damage and apoptosis in BALB/c mice.

Microcystins (MCs), the products of blooming algae Microcystis, are waterborne environmental toxins that have been implicated in the development of liver cancer, necrosis, and even fatal intrahepatic bleeding. Alternative protective approaches in addition to complete removal of MCs in drinking water are urgently needed. In our previous work, we found that sulforaphane (SFN) protects against microcystin-LR (MC-LR)-induced cytotoxicity by activating the NF-E2-related factor 2 (Nrf2)-mediated defensive response in human hepatoma (HepG2) and NIH 3T3 cells.

Proteins as binding targets of isothiocyanates in cancer prevention.

Isothiocyanates are versatile cancer-preventive compounds. Evidence from animal studies indicates that the anticarcinogenic activities of ITCs involve all the major stages of tumor growth: initiation, promotion and progression. Epidemiological studies have also shown that dietary intake of ITCs is associated with reduced risk of certain human cancers.