Serum CA72-4 is specifically elevated in gout patients and predicts flares.

OBJECTIVES: Serum CA72-4 levels are elevated in some gout patients but this has not been comprehensively described. The present study profiled serum CA72-4 expression in gout patients and verified the hypothesis that CA72-4 is a predictor of future flares in a prospective gout cohort. METHODS: To profile CA72-4 expression, a cross-sectional study was conducted in subjects with gouty arthritis, asymptomatic hyperuricaemia, four major arthritis types (OA, RA, SpA, septic arthritis) and healthy controls. A prospective gout cohort study was initiated to test the value of CA72-4 for predicting gout flares. During a 6-month follow-up, gout flares, CA72-4 levels and other gout-related clinical variables were observed at 1, 3 and 6 months. RESULTS: CA72-4 was highly expressed in patients with gouty arthritis [median (interquartile range) 4.55 (1.56, 32.64) U/ml] compared with hyperuricaemia patients [1.47 (0.87, 3.29) U/ml], healthy subjects [1.59 (0.99, 3.39) U/ml] and other arthritis patients [septic arthritis, 1.38 (0.99, 2.66) U/ml; RA, 1.58 (0.95, 3.37) U/ml; SpA, 1.56 (0.98, 2.85) U/ml; OA, 1.54 (0.94, 3.34) U/ml; P < 0.001, respectively]. Gout patients with frequent flares (twice or more in the last year) had higher CA72-4 levels than patients with fewer flares (fewer than twice in the last year). High CA72-4 level (>6.9 U/ml) was the strongest predictor of gout flares (hazard ratio = 3.889). Prophylactic colchicine was effective, especially for patients with high CA72-4 levels (P = 0.014). CONCLUSION: CA72-4 levels were upregulated in gout patients who experienced frequent flares and CA72-4 was a useful biomarker to predict future flares.

Baseline urate level and renal function predict outcomes of urate-lowering therapy using low doses of febuxostat and benzbromarone: a prospective, randomized controlled study in a Chinese primary gout cohort.

BACKGROUND: Low doses of febuxostat or benzbromarone are widely used in Asian countries, but lacking studies to compare the efficacy and safety of the two urate-lowering drugs. METHODS: To compare the efficacy and safety of low-dose febuxostat with low-dose benzbromarone in patients with primary gout, a randomized controlled, open-label trial was performed among male patients with primary gout for urate-lowering therapy (ULT) in a dedicated gout clinic in China. Randomization was carried out by a third-party institution according to random number table. Patients were randomly assigned 1:1 to febuxostat group (Feb group) (20 mg daily) or benzbromarone group (Ben group) (25 mg daily) and treated for 12 weeks. General information and biochemical data were collected at baseline and at every visit monthly. Clinical characteristics before and after the ULT were analyzed in the two groups by SPSS and EmpowerStats software. RESULTS: Two hundred forty patients were enrolled and randomized in the two groups, with 214 patients completing 12 weeks' ULT (105 in the Feb group and 109 in the Ben group). After 12 weeks, substantial percentages of patients in both Feb and Ben group achieved the target serum uric acid (sUA) (< 360 µmol/L) and serum urate levels were reduced significantly for both groups (Feb 39.5% and 156.83 µmol/L vs. Ben 35.7% and 163.99 µmol/L). Multivariate analysis suggests baseline sUA level and renal function were associated with the outcome of the rate of achieving target sUA (RAT). Sub-group analysis suggests low doses of febuxostat and benzbromarone rendered better RAT for patients with sUA < 540 µmol/L and creatinine clearance rate (Ccr) ≤ 110 mL min-1 1.73 m-2 at baseline. The drugs were well tolerated, and the incidence of gout flares in Feb group was similar with that in Ben group (22.85% vs. 33.94%). CONCLUSION: Overall, febuxostat 20 mg daily and benzbromarone 25 mg daily reduced sUA, and gout patients with sUA level < 540 µmol/L or Ccr ≤ 110 mL min-1 1.73 m-2 at baseline had better chance to achieve target uric acid levels. The current study suggests sUA level and renal function are key factors to consider when recommending low doses of febuxostat and benzbromarone to gout patients. TRIAL REGISTRATION: Registered with ChiCTR, No. ChiCTR1800019352 (retrospectively registered).

3D Viscoplastic Finite Element Modeling of Dislocation Generation in a Large Size Si Ingot of the Directional Solidification Stage.

Growing very large size silicon ingots with low dislocation density is a critical issue for the photovoltaic industry to reduce the production cost of the high-efficiency solar cell for affordable green energy. The thermal stresses, which are produced as the result of the non-uniform temperature field, would generate dislocation in the ingot. This is a complicated thermal viscoplasticity process during the cooling process of crystal growth. A nonlinear three-dimensional transient formulation derived from the Hassen-Sumino model (HAS) was applied to predict the number of dislocation densities, which couples the macroscopic viscoplastic deformation with the microscopic dislocation dynamics. A typical cooling process during the growth of very large size (G5 size: 0.84 m × 0.84 m × 0.3 m) Si ingot is used as an example to validate the developed HAS model and the results are compared with those obtained from qualitatively critical resolved shear stress model (CRSS). The result demonstrates that this finite element model not only predicts a similar pattern of dislocation generation with the CRSS model but also anticipate the dislocation density quantity generated in the Si ingot. A modified cooling process is also employed to study the effect of the cooling process on the generation of the dislocation. It clearly shows that dislocation density is drastically decreased by modifying the cooling process. The results obtained from this model can provide valuable information for engineers to design a better cooling process for reducing the dislocation density produced in the Si ingot under the crystal growth process.

Traditional versus Percutaneous Transforaminal Endoforaminal Discectomy Effect on the Nervous System Function and Serum LEK, GFAP and PGE-2 in Patients with Senile Lumbar Spinal Stenosis.

OBJECTIVE: To compare the influence of percutaneous transforaminal endoscopic discectomy (PTED) and traditional operation on the nervous system function and the serum leu-enkephalin (LEK), glial fibrillary acidic protein (GFAP) and prostaglandin E-2 (PGE-2) in patients with senile lumbar spinal stenosis. STUDY DESIGN: Experimental study. PLACE AND DURATION OF STUDY: Department of Orthopedics Two, Xinjiang Changji Hui Autonomous Prefecture People's Hospital, Xinjiang, China, from March 2017 to March 2018. METHODOLOGY: A total of 146 patients with senile lumbar spinal stenosis were randomly divided into control group and observation group, 73 in each group. Control group underwent traditional operation, while the observation group underwent PTED. General situation of operation, serum LEK, GFAP, PGE-2, American Spinal Injury Association (ASIA) score and Japanese Orthopaedic Association (JOA) score were compared. RESULTS: Intraoperative blood loss in observation group was less than that in control group (p<0.001). Both operation time and length of hospital stay in observation group were shorter than those in control group (both p<0.001). At 24 hours later after operation, both levels of serum LEK and ASIA score in observation group were higher than those in control group (p=0.006 and p<0.001, respectively), and levels of serum GFAP and PGE-2 and JOA score in observation group were all lower than those in control group (all p<0.001). CONCLUSION: Compared with traditional operation, PTED has the advantages of less intraoperative blood loss, shorter operation time and length of hospital stay, etc. Besides, PTED can effectively reduce serum LEK, BFGF and PGE-2 expression in patients; and dramatically improve their nervous system function and lumbar function.

Urate-lowering therapy alleviates atherosclerosis inflammatory response factors and neointimal lesions in a mouse model of induced carotid atherosclerosis.

Hyperuricemia (HU) is a cause of gout. Clinical studies show a link between HU and cardiovascular disease. However, the role of soluble serum urate (SU) on atherosclerosis development remains elusive. We aimed to use a new HU mouse model [Uricase/Uox knockout (KO)] to further investigate the relationship between HU and atherosclerosis. A mouse model by perivascular collar placement of induced carotid atherosclerosis was established in male Uox-KO mice. The Uox-KO mice had elevated SU levels and enhanced levels of atherosclerosis inflammatory response proteins. In contrast, Uox-KO mice with carotid atherosclerosis showed severe neointimal changes in histology staining consistent with increases in intimal area and increases in proliferating cell nuclear antigen (PCNA)- and F4/80-positive cells. Allopurinol reduced neointimal areas induced by the perivascular collar in hyperuricemic mice, accompanied by decreased expression of PCNA- and F4/80-positive cells. Urate-lowering treatment alleviated atherosclerosis inflammatory response factors and reactive oxygen species (ROS) intensities in both collar placement Uox-KO mice and urate-stimulated human umbilical vein endothelial cells (HUVECs). In vitro results using HUVECs showed ROS was induced by urate and ROS induction was abrogated using antioxidants. These data demonstrate that urate per se does not trigger atherosclerosis intima lesions in male mice. Urate worsens carotid neointimal lesions induced by the perivascular collar and urate-lowering therapy partially abrogates the effects. The current study warrants clinical studies on the possible benefits of urate-lowering therapy in atherosclerosis patients with HU.

IBI303, a biosimilar to adalimumab, for the treatment of patients with ankylosing spondylitis in China: a randomised, double-blind, phase 3 equivalence trial.

BACKGROUND: China approved adalimumab for the treatment of ankylosing spondylitis in 2013. However, the cost of the standard dose regimen exceeds ¥15 000 (around US$2250) per month, which is well beyond affordability for most Chinese patients. No biosimilars of adalimumab are available in China; IBI303 is a monoclonal antibody against TNFα that is currently in development. This study aimed to assess the clinical equivalence of IBI303 to adalimumab in patients with ankylosing spondylitis. METHODS: This phase 3, multicenter, double-blind, parallel, randomised controlled equivalence trial was done in 20 centers across China. Patients were randomly assigned in a 1:1 ratio to receive either 40 mg of IBI303 or 40 mg of adalimumab as a subcutaneous injection every 2 weeks until week 22. Patients were eligible for inclusion if they were between 18 and 65 years old, fulfilled the 1984 Modified New York Criteria for ankylosing spondylitis, were non-responders, inadequate responders, or intolerant to treatment with NSAIDs for 4 or more weeks, and had active ankylosing spondylitis defined by two or more indicators of disease severity. The investigators, site staff, patients, sponsors, and the contract research organisation were masked to treatment allocation. The primary outcome was the proportion of patients who met the Assessment of SpondyloArthritis international Society (ASAS) Response Criteria for a 20% improvement (ASAS20) at week 24 after treatment. Equivalence was established if the 95% CI of the difference in responses between groups was between -15% and 15%. Efficacy analyses were done in the full analysis population and in the per-protocol population. Safety analyses were done in all randomly assigned patients who received at least one drug dose. This trial is registered with ClinicalTrials.gov, number NCT02893254. FINDINGS: Between Sept 22, 2016, and May 11, 2018, 438 patients were randomly allocated either to the biosimilar IBI303 group (n=220) or the adalimumab group (n=218). In the full analysis population, 165 (75%) of 220 patients in the IBI303 group (95% CI 68·7-80·6) and 158 (72%) of 218 patients in the adalimumab group (66·0-78·3) reached the primary outcome of ASAS20 at week 24. The difference between the two groups was 2·3% with a 95% CI of -5·9 to 10·6, which fell within the pre-specified equivalence boundaries at week 24 (-15 to 15). In the per-protocol population, 163 (80%) of 203 patients in the IBI303 group reached ASAS20 at week 24 (95% CI 74·1-85·5), compared with 150 (80%) of 188 patients in the adalimumab group (73·3-85·3%). The difference between the groups was 0·6% with a 95% CI of -7·4 to 8·6%, which also fell within the pre-specified equivalence boundaries at week 24. Safety and tolerability profiles were similar between the two groups; 174 (79%) of 220 patients in the IBI303 group and 178 (82%) of 218 patients in the adalimumab group had treatment-emergent adverse events. INTERPRETATION: This trial showed therapeutic equivalence of IBI303 and adalimumab in the treatment of ankylosing spondylitis. The efficacy, safety, and immunogenicity of both drugs are highly similar. IBI303 could be an alternative treatment option for patients with ankylosing spondylitis in China. FUNDING: Innovent Biologics, National Major Scientific and Technological Special Project for "Significant New Drugs Development".

Clinical characteristics associated with subcutaneous tophi formation in Chinese gout patients: a retrospective study.

The objective of this study is to analyze clinical characteristics associated with the formation of subcutaneous tophi among Chinese gout patients. It was a retrospective outpatient cohort study. Five thousand six hundred ninety-three gout patients treated at the Affiliated Hospital of Qingdao University from March 2011 to February 2016 were included and divided into the tophus group and non-tophus group according to the presence of megascopic tophus. Relevant clinical information and biochemical parameters were analyzed to identify potential risk factors for the incidence of subcutaneous tophi. There are significant difference (P < 0.05) between the tophus and non-tophus groups in gender, family history, exercise, incidence of obesity, hypertension, renal dysfunction, kidney stone, coronary heart disease, and upper limb joint involvement. Between the two groups, significant difference (P < 0.01) was detected in the onset age (43.80 ± 13.82 years vs. 45.40 ± 13.77 years), duration of disease (10.28 ± 7.54 years vs. 5.11 ± 6.06 years), number of joint involved (3.11 ± 2.15 vs. 1.81 ± 1.35), systolic pressure (138.53 ± 19.46 mmHg vs. 133.87 ± 17.93 mmHg), diastolic pressure (89.55 ± 12.73 mmHg vs. 87.48 ± 11.77 mmHg), serum uric acid (487.15 ± 120.13 µmol/L vs. 458.89 ± 119.04 µmol/L), creatinine (93.87 ± 54.19 µmol/L vs. 85.51 ± 37.71 µmol/L), and creatinine clearance rate (Ccr) (93.05 ± 48.7 mL/min vs. 106.61 ± 51.76 mL/min). Logistic regression analysis suggests that duration of disease, number of joints involved, involvement of upper limb joints, kidney stones, diastolic pressure, and serum uric acid are associated with the subcutaneous tophi formation, while exercise and obesity are protective factors. The present study has identified several clinical parameters (such as duration of disease, involvement of upper limb joints, involved joints, kidney stone, hypertension) as risk factors for the incidence of subcutaneous tophi, which provides insights into the treatment and prevention of tophus.

MLL-AF9-induced leukemogenesis requires coexpression of the wild-type Mll allele.

Oncogenic fusion proteins are capable of initiating tumorigenesis, but the role of their wild-type counterparts in this process is poorly understood. The mixed lineage leukemia (MLL) gene undergoes chromosomal translocations, resulting in the formation of oncogenic MLL fusion proteins (MLL-FPs). Here, we show that menin recruits both wild-type MLL and oncogenic MLL-AF9 fusion protein to the loci of HOX genes to activate their transcription. Wild-type MLL not only catalyzes histone methylation at key target genes but also controls distinct MLL-AF9-induced histone methylation. Notably, the wild-type Mll allele is required for MLL-AF9-induced leukemogenesis and maintenance of MLL-AF9-transformed cells. These findings suggest an essential cooperation between an oncogene and its wild-type counterpart in MLL-AF9-induced leukemogenesis.

Apoptosis induction in human lung adenocarcinoma cells by oil-soluble allyl sulfides: triggers, pathways, and modulators.

DAS (diallyl sulfide), DADS (diallyl disulfide), and DATS (diallyl trisulfide) are major oil-soluble allyl sulfides (OAS) that represent major garlic constituents. The anticarcinogenic and antimutagenic effects of these substances have been extensively studied during the last decades. Previous reports suggest that induction of apoptosis by OASs might contribute to their chemopreventive effects. In this study, we report that OASs DADS and DATS induce significant apoptosis in human lung adenocarcinoma A549 cells, whereas DAS does not. Differential modulation of reactive oxygen intermediates (ROI) and mitochondria membrane potential (MMP) may account for the apoptotic effects of DADS and DATS. The underlying molecular mechanisms of apoptosis induction by both compounds include activation of C-Jun N-terminal kinase (JNK), up-regulation of p53, and down-regulation of bcl-2 expression. In our test series, up-regulation of extracellular signal-regulated protein kinase (ERK) was dispensable for apoptosis induction; DAS, DADS, or DATS did not modify expression of MAPK p38, bax, and bcl-xL. Further investigation revealed that the specific JNK inhibitor SP600125 and the antioxidant NAC blocked DADS and DATS-induced apoptosis, whereas ERK inhibitors did not. Additionally, our data provide the first evidence that Fas-mediated cell death pathway is partly involved in DADS but not DATS-mediated cell death. Taken together, our work has elucidated the triggers, important modulators, and signal transduction pathways in DADS and DATS-mediated apoptosis.

Menin, histone h3 methyltransferases, and regulation of cell proliferation: current knowledge and perspective.

Menin is a tumor suppressor encoded by the MEN1 gene that is mutated in patients with an inherited syndrome, multiple endocrine neoplasia type 1 (MEN1). Loss of menin has potent impact on proliferation of endocrine and non-endocrine cells. However, until recently little has been known as to how menin regulates cell proliferation. Rapid research progress in the past several years suggests that menin represses proliferation of endocrine cells yet promotes proliferation in certain types of leukemia cells via interacting with various transcriptional regulators. Menin interacts with histone H3 methyltransferases such as MLL (mixed lineage leukemia) protein. Increasing evidence has linked the biological function of menin to epigenetic histone modifications, control of the pattern of gene expression, and regulation of cell proliferation in a cell type-specific manner. In light of these recent findings, an emerging model suggests that menin is a crucial regulator of histone modifiers by acting as a scaffold protein to coordinate gene transcription and cell proliferation in a cell context-dependent manner. This recent progress unravels the coordinating role of menin in epigenetics and regulation of cell cycle, providing novel insights into understanding regulation of beta cell functions and diabetes, as well as the development and therapy of endocrine tumors and leukemia.

Glutathione- and thioredoxin-related enzymes are modulated by sulfur-containing chemopreventive agents.

We studied the effects of sulfur-containing chemopreventive agents, including allyl sulfides and isothiocyanates, on human redox networks. Isothiocyanates inhibited isolated redox-active enzymes in a time- and dose-dependent manner. As shown for the most active compound, benzyl isothiocyanate (BITC), on thioredoxin reductase, the inhibition has an initial competitive part (Ki=6.1+/-1.0 microM) followed by a time-dependent irreversible inhibition (k2=72.8+/-25.5 M(-1) s(-1)). Also, glutathione reductase and glutathione S-transferase were irreversibly modified by BITC. Sulforaphane led to irreversible inhibition of the studied redox enzymes, but with 5-10 times lower k2 values. In contrast, allyl sulfides had only moderate effects on the tested enzymes. However, diallyl disulfide was found to react directly with reduced glutathione (k2=100 M(-2) s(-1)). This reaction might contribute to enhanced oxidative stress and the induction of the selenoprotein glutathione peroxidase as determined on activity and transcript levels. All chemopreventive agents tested induced transcript levels of genes associated with cell cycle arrest and apoptosis. This upregulation was accompanied by a dose-dependent decrease in cell number. Our data indicate that modulation of cellular redox networks is likely to contribute to the effects of sulfur-containing chemopreventive agents.

Targeting ROS: selective killing of cancer cells by a cruciferous vegetable derived pro-oxidant compound.

Oncogenic transformation usually leads to increase of cellular reactive oxygen species (ROS) level that renders the cells vulnerable to additional ROS production. By targeting ROS, a naturally occurring ROS-inducing compound, beta-phenylethyl isothiocyanate (PEITC), selectively kills the transformed cells but not normal cells.

Regulation of Cbfa1 expression by total flavonoids of Herba epimedii.

Core binding factor alpha1 (Cbfa1) is a member of the runt family of transcription factors, which appears to play a pivotal role in regulating the differentiation of osteoblastic precursors and the activity of mature osteoblasts. Total flavonoids of Herba epimedii (HEF) is a recognized bone anabolic agent, but there is lack of reports on the modulation of Cbfa1 expression by HEF. Here we investigated the effect of HEF on Cbfa1 expression in the bone of ovariectomized (OVX) rats. HEF could increase the expression of Cbfa1 mRNA in the bone of ovariectomized rats in a dose-dependent manner. Furthermore, the high dose HEF (160 mg/kg) administered for 12 weeks in vivo stimulated osteocalcin expression. These findings suggest that Cbfa1 is required for mediating the anabolic effects of HEF.

The production of reactive oxygen species and the mitochondrial membrane potential are modulated during onion oil-induced cell cycle arrest and apoptosis in A549 cells.

Protective effects of Allium vegetables against cancers have been shown extensively in experimental animals and epidemiologic studies. We investigated cell proliferation and the induction of apoptosis by onion oil extracted from Allium cepa, a widely consumed Allium vegetable, in human lung cancer A549 cells. GC/MS analysis suggested that propyl sulfides but not allyl sulfides are major sulfur-containing constituents of onion oil. Onion oil at 12.5 mg/L significantly induced apoptosis (13% increase of apoptotic cells) as indicated by sub-G1 DNA content. It also caused cell cycle arrest at the G2/M phase; 25 mg/L onion oil increased the percentage of G2/M cells almost 6-fold compared with the dimethyl sulfoxide control. The action of onion oil may occur via a reactive oxygen species-dependent pathway because cell cycle arrest and apoptosis were blocked by the antioxidants N-acetylcysteine and exogenous glutathione. Marked collapse of the mitochondrial membrane potential suggested that dysfunction of the mitochondria may be involved in the oxidative burst and apoptosis induced by onion oil. Expression of phospho-cdc2 and phospho-cyclin B1 were downregulated by onion oil, perhaps accounting for the G2/M arrest. Overall, these results suggest that onion oil may exert chemopreventive action by inducing cell cycle arrest and apoptosis in tumor cells.

Chlorinated river and lake water extract caused oxidative damage, DNA migration and cytotoxicity in human cells.

Consumption of chlorinated drinking water is suspected to be associated with adverse health effects, including mutations and cancer. In the present study, the genotoxic potential of water from Donghu lake, Yangtze river and Hanjiang river in Wuhan, an 8-million metropolis in China, was investigated using HepG2 cells and the alkaline version of the comet assay. It could be shown that all water extracts caused dose-dependent DNA migration in concentrations corresponding to dried extracts of 0.167-167 ml chlorinated drinking water per ml medium. To explore whether the intracellular redox status is regulated by chlorinated drinking water, we determined lipid peroxidation (LPO) and depletion of reduced glutathione (GSH). The malondialdehyde (thiobarbituric acid (TBA)-reactive aldehydes) concentration increased after chlorinated drinking water treatment of HepG2 cells in a dose-dependent manner, the GSH content decreased. The activity of lactate dehydrogenase (LDH) increased in chlorinated drinking water treated HepG2 cells indicating cytotoxicity. In accordance with former studies which dealt with in vivo and in vitro micronucleus induction the present study shows that chlorinated drinking water from polluted raw water may entail genetic risks.

The role of reactive oxygen species (ROS) production on diallyl disulfide (DADS) induced apoptosis and cell cycle arrest in human A549 lung carcinoma cells.

Diallyl disulfide (DADS), an oil soluble constituent of garlic (Allium sativum), has been reported to cause antimutagentic and anticarcinogenic effects in vitro and in vivo by modulating phases I and II enzyme activities. In recent years, several studies suggested that the chemopreventive effects of DADS can also be attributed to induction of cell cycle arrest and apoptosis in cancer cells. In the present study, we reported that DADS-induced cell cycle arrest at G2/M and apoptosis in human A549 lung cancer cells in a time- and dose-dependent manner. Additionally, a significant increase of intracellular reactive oxygen species (ROS) was induced in A549 cells less than 0.5h after DADS treatment, indicating that ROS may be an early event in DADS-modulated apoptosis. Treatment of A549 cells with N-acetyl cysteine (NAC) completely abrogated DADS-induced cell cycle arrest and apoptosis. The result indicated that oxidative stress modulates cell proliferation and cell death induced by DADS.

Vinclozolin, a widely used fungizide, enhanced BaP-induced micronucleus formation in human derived hepatoma cells by increasing CYP1A1 expression.

Vinclozolin, a widely used fungicide, can be identified as a residue in numerous vegetable and fruit samples. To get insight in its genetic toxicity, we investigated the genotoxic effect of vinclozolin in the human derived hepatoma cell line HepG2 using the micronucleus (MN) assay. Additionally, to evaluate the co- or anti-mutagenic potency of vinclozolin, we treated HepG2 cells with different concentrations of vinclozolin for 24 h. Subsequently, the cells were exposed to benzo[a]pyrene (BaP) for 1h. Exposure of HepG2 cells to 50-400 microM vinclozolin alone did not cause any induction of micronuclei. However, a pronounced co-mutagenic effect was observed. MN frequencies caused by BaP increased by 30.6%, 52.8% and 65.3% after pretreatment of the cell cultures with 50, 100 and 200 microM vinclozolin, respectively. The highest concentration (400 microM) of vinclozolin tested caused cytotoxicity. Therefore, micronuclei were not considered for that concentration. To clarify the mechanism of cogenotoxicity, we assayed cytochrome P450 1A1 (CYP1A1), which plays a pivotal role in activation of BaP. Cells exposed to vinclozolin led to significant increase of CYP1A1 expression in Western blot. The result suggested that induction of CYP1A1 by vinclozolin account for its enhancing effect on genotoxicity caused by BaP.

Induction of apoptosis in tumor cells by naturally occurring sulfur-containing compounds.

Chemoprevention is regarded as one of the most promising and realistic approaches in the prevention of human cancer. Among naturally occurring products, sulfur-containing compounds (OSCs), especially garlic compounds (GCs) and isothiocyanates (ITCs), represent two important and promising chemopreventive families because of their potent chemopreventive effects in various in vivo and in vitro models. In recent years, numerous investigations have shown that sulfur-containing compounds induce apoptosis in multiple cell lines and experimental animals. In the course of apoptosis induction by GCs and ITCs, multiple signal-transduction pathways and apoptosis intermediates are modulated. In particular, modulation of MAPKs and production of reactive oxygen species (ROS) seem to play pivotal roles in apoptosis induction by most GCs and ITCs. However, the role of P53 is still controversial. Based on present knowledge, GCs and ITCs may target not only the metabolism of carcinogens but also apoptosis signaling molecules. The effects of ITCs and GCs at multiple points of cancer development make these compounds highly promising candidates in cancer chemoprevention. However, the mechanisms of their anticancer effects are not fully understood, and further studies are required, especially to elucidate the role of cell-death receptors (the extrinsic pathway) and whether these agents induce apoptotic effects in non-tumor cells.

Use of a human-derived liver cell line for the detection of cytoprotective, antigenotoxic and cogenotoxic agents.

In this paper, we reviewed the data on the use of HepG2 cells to detect cytoprotective, antigenotoxic and cogenotoxic agents. Owing to their intact and inducible phase I and phase II enzymes, HepG2 cells are able to activate and detoxify xenobiotics and therefore reflect the metabolism of xenobiotics in the human body better than other metabolically incompetent cells used in conventional in vitro assays. Several dietary and non-dietary agents were found to be protective against different groups of cytotoxic and DNA-damaging xenobiotics in HepG2 cells and the mechanism of protection includes scavenging of electrophiles, reactive oxygen species and peroxides, inhibition of phase I activating enzymes, induction of phase II detoxifying enzymes and interactions with DNA-repair and/or replication processes. Additionally, certain non-mutagenic substances were found to enhance the effect of genotoxic agents in HepG2 cells by increasing the metabolic activation of the latter. In conclusion, HepG2 cells are of great relevance to detect cytotoxic and genotoxic substances and by extension cytoprotective, antigenotoxic and cogenotoxic agents.