Biomedical subjects

Jie Chen

Publications and source records attributed to Jie Chen.

At least 145 records · Page 8Linked to original sources

PubMed2005

Protective role of heat shock protein 27 in gastric mucosal injury.

Heat shock protein 27 (HSP27) mediates cytoprotective effects through its function as a molecular chaperone and through the phosphorylation-dependent stabilization of actin filaments. The role of HSP27 in gastric ulcer formation and healing is, however, unknown. The expression of HSP27 was studied in human gastric tissue specimens obtained from patients with gastric ulcers and from healthy Helicobacter pylori-negative individuals, who received low-dose aspirin, rofecoxib, and the combination in a prospective study. The susceptibility of the gastric mucosa to indomethacin-induced lesions was further studied in transgenic mice overexpressing human HSP27 (Tg(huHSP27)) and compared with wild-type mice (Wt). The expression of HSP27, COX-1, and COX-2 was investigated in Tg(huHSP27) mice and Wt mice by immunohistochemistry and western blot analysis. While no specific changes in HSP27 expression were found following exposure of healthy human gastric mucosa to oral administration of aspirin or refocoxib, chronic gastric ulcers showed strong HSP27 expression at the ulcer base and margins. Here it was expressed by granulation tissue and regenerating surface epithelium. In Tg(huHSP27) mice, overexpression of HSP27 led to a significant decrease of indomethacin-induced erosions and ulcers compared with Wt mice. COX-1 and COX-2 levels did not change. HSP27 is involved in chronic gastric ulcer repair mechanisms in humans, while overexpression of human HSP27 in gastric epithelial cells in mice reduces the susceptibility to non-steroidal anti-inflammatory drug (NSAID)-induced gastric ulceration. This indicates that HSP27 expression is critical for mucosal protection in the stomach.

Aged↗

PubMed2005

Overexpression of cathepsin B in gastric cancer identified by proteome analysis.

We aimed to validate an analytical approach based on proteomics on gastric cancer specimens for the identification of new putative diagnostic or prognostic markers. Primary screening was performed on gastrectomy specimens obtained from ten consecutive patients with gastric cancer. Gastric epithelial cells were obtained with an epithelial cell enrichment technique, homogenized and then separated by two-dimensional polyacrylamide gel electrophoresis (2-D PAGE). The differential protein expression pattern was verified stepwise by Western blotting and immunohistochemistry on samples from 28 and 46 cancer patients, respectively. The putative clinical applicability and prognostic use were tested by an enzyme-linked immunoabsorbent assay on serum samples obtained from 149 cancer patients. One hundred-ninety-one differentially expressed protein spots were found by 2-D PAGE and identified by mass spectrometry, including cathepsin B, which was over-expressed in six (60%) patients. Western blotting confirmed that the active form of cathepsin B is over-expressed, while immunohistochemistry showed strong cytoplasmic staining in cancer tissues of 45 (98%) patients. The serum level of cathepsin B was increased in patients with gastric cancer compared to healthy controls (P = 0.0026) and correlated with T-category and the presence of distant metastases (P < 0.05). Serum levels above 129 pmol x L(-1) were associated with a reduced survival rate (P = 0.0297). Proteome analysis is a valuable tool for the identification of prognostic markers in gastric cancer: Increased cathepsin B serum levels are associated with advanced tumor stages and progressive disease, which enables the classification of some gastric cancer patients into a subgroup that should undergo aggressive therapy.

Adult↗

PubMed2005

Antisense bcl-2 transfection up-regulates anti-apoptotic and anti-oxidant thioredoxin in neuroblastoma cells.

Antisense bcl-2 therapy combined with chemotherapy has been proved to be effective in various tumors. However, the role played by antisense bcl-2 therapy alone is not clear. In this study, we compared the apoptosis and the protein profiles of antisense bcl-2 transfected human neuroblastoma SK-N-MC cells to the control cells. Flow cytometric data indicated that antisense bcl-2 transfection did not lead to more extensive apoptosis in SK-N-MC cells (14.9 +/- 3.8%) than the control cells (10.3 +/- 2.3%). The above observation was confirmed by fluorescence microscopy using Hoechst 33258 staining. However, antisense bcl-2 induced changes in the expression of various proteins as shown by proteomic comparison, which included the up-regulation of the anti-apoptotic and anti-oxidant protein thioredoxin. By western blot validation, thioredoxin was found to be up-regulated by 2.9-folds with the corresponding down-regulation of Bcl-2 by 2.1-folds. The up-regulation of thioredoxin may be a compensating mechanism for cell survival in neuroblastoma when Bcl-2 expression is suppressed, and it may to some extent attenuate the effectiveness of antisense bcl-2 therapy.

Apoptosis↗

PubMed2005

Thermodynamics of the interaction of aluminum ions with DNA: implications for the biological function of aluminum.

Aluminum is a known neurotoxic agent and its neurotoxic effects may be due to its binding to DNA. However, the mechanism for the interaction of aluminum ions with DNA is not well understood. Here, we report the application of isothermal titration calorimetry (ITC), fluorescence spectroscopy, and UV spectroscopy to investigate the thermodynamics of the binding of aluminum ions to calf thymus DNA (CT DNA) under various pH and temperature conditions. The binding reaction is driven entirely by a large favorable entropy increase but with an unfavorable enthalpy increase in the pH range of 3.5-5.5 and at all temperatures examined. Aluminum ions show a strong and pH-dependent binding affinity to CT DNA, and a large positive molar heat capacity change for the binding, 1.57 kcal mol(-1) K(-1), demonstrates the burial of the polar surface of CT DNA upon groove binding. The fluorescence of ethidium bromide bound to CT DNA is quenched by aluminum ions in a dynamic way. Both Stern-Volmer quenching constant and the binding constant increase with the increase of the pH values, reaching a maximum at pH 4.5, and decline with further increasing the pH to 5.5. At pH 6.0 and 7.0, aluminum ions precipitate CT DNA completely and no binding of aluminum ions to CT DNA is observed by ITC. Combining the results from these three methods, we conclude that aluminum ions bind to CT DNA with high affinity through groove binding under aluminum toxicity pH conditions and precipitate CT DNA under physiological conditions.

Aluminum↗

PubMed2005

Congenital iodine deficiency and hypothyroidism impair LTP and decrease C-fos and C-jun expression in rat hippocampus.

Iodine is essential for the synthesis of triiodothyronine (T(3)) and thyroxine (T(4)). Iodine deficiency leads to inadequate thyroid hormone. Thyroid hormones deficiency during brain development affects cognitive functions, such as attention, learning, and memory. However, the mechanism underlying these deficits is unclear. To investigate the role of iodine deficiency and hypothyroidism in synaptic plasticity, this study examined the induction of long-term synaptic plasticity (LTP) and expression of immediate early (IEA) gene proteins in rat hippocampus following congenital iodine deficiency or hypothyroidism. Through gestation and lactation, iodine-deficient or hypothyroid dam rats were administered with either iodine-deficient diet or methimazole-added drinking water. Exposure was terminated on postnatal day (PN) 30. In hippocampus of pup rats, the induction of LTP in area CA1 was determined on PN60 and the expression of c-fos and c-jun proteins was examined on PN20, PN30 and PN60. Compared to control pups, both treated groups have shown: (1) significantly lower concentrations of serum FT(3) and FT(4), (2) much smaller population spike (PS) amplitude (p<0.01) and field-excitatory postsynaptic potential (f-EPSP) slope induced by high-frequency stimulation (HFS) (P<0.01), and (3) significantly lower integrated optical density (IOD) total of c-fos and c-jun expression (P<0.05 or P<0.01). In summary, iodine deficiency and hypothyroidism during critical periods of brain development impair LTP induction and decrease the expression of c-fos and c-jun proteins in hippocampus.

Aging↗

PubMed2005

Antioxidants and trichostatin A synergistically protect against in vitro cytotoxicity of Ni2+ in human hepatoma cells.

The objective of this study was to investigate the separate and combined effects of antioxidants, trichostatin A (TSA) and their combination on the in vitro cytotoxicity of Ni2+ in human hepatoma cells. Cell viability, lactate dehydrogenase (LDH) release, and DNA fragmentation were measured as indicators of cell damage. Reactive oxygen species (ROS) generation and histone acetylation were also measured. The cytotoxicity of Ni2+ increased in a time- and dose-dependent manner. In the presence of 2 mM Ni2+, ROS generation increased 365% (p<0.05), while histone acetylation decreased 37% (p<0.05). Although antioxidants, ascorbic acid (AA, 0.5 or 1 mM), reduced glutathione (GSH, 100 or 200 microM) and N-acetyl-cysteine (NAC, 0.5 or 1 mM) strongly inhibited ROS generation, their effect on Ni2+-caused histone hypoacetylation was not so obvious. On the contrary, TSA (100 nM) showed no inhibition on ROS generation but significantly increased histone acetylation in both control and Ni2+-exposed cells. As expected, the combination of antioxidants and TSA possessed the activity of both diminishing ROS generation and increasing histone hypoacetylation caused by Ni2+. Further studies found that both antioxidants and TSA could diminish the cytotoxicity of Ni2+, and their combined effects obviously improved each of their protection roles, indicating that both ROS generation and histone hypoacetylation are involved in the cytotoxicity of Ni2+, and the combination of antioxidants and TSA may act as a useful strategy to protect against this cytotoxicity.

Acetylation↗

PubMed2005

Evidence of an immune-mediated mechanism for an idiosyncratic nevirapine-induced reaction in the female Brown Norway rat.

Previously, we reported a new animal model of an idiosyncratic drug reaction in which nevirapine causes a skin rash in some rats that has characteristics similar to the reaction that occurs in humans. Strong evidence that the reaction is immune-mediated was found; specifically, low-dose pretreatment induced tolerance, while with rechallenge, the time to onset decreased and the severity increased. Furthermore, splenocytes from rechallenged rats transferred rash susceptibility to naïve recipients. We now report the results of studies to explore the immune aspects of this reaction. T cells were found to play an important role, as demonstrated by their ability to adoptively transfer susceptibility to the skin reaction. Of these T cells, CD4+ cells are the likely effectors because they were capable of transferring susceptibility and the reaction was delayed in rats partially depleted of CD4+ T cells. In contrast, it appears that CD8+ T cells are not essential, as CD8+ T cells were unable to transfer sensitivity to a naïve animal and rats depleted of CD8+ T cells still developed skin rash. Unlike the penicillamine model, where we have demonstrated that the tolerance induced by low-dose treatment is immune-mediated, tolerance induced by low-dose nevirapine appears to be largely due to induction of metabolism as it can be overcome by inhibition of cytochrome P450. Pretreatment with the immunosuppressants, cyclosporine and tacrolimus, prevented the rash and even led to resolution of the rash during nevirapine treatment. These studies reinforce the hypothesis that the reaction in this model is similar to that which occurs in humans. In particular, the finding that CD4+ T cells may play a central role in this model fits with the observation that the incidence of idiosyncratic reactions to nevirapine in humans appears to be lower in patients with low CD4+ counts.

Adoptive Transfer↗

PubMed2005

Calmodulin regulates the post-anaphase reposition of centrioles during cytokinesis.

A transient postanaphase repositioning of the centriole is found to control the completion of cytokinesis. Using a green fluorescent protein-calmodulin fusion protein as a living cell probe, we have previously found that calmodulin is associated with the initiation and progression of cytokinesis. In this study, we further studied the effect of calmodulin on the repositioning of the centriole and subsequent cell cycle progression. When activity of calmodulin is inhibited, the regression of the centriole from the intercellular bridge to the cell center is blocked, and thus the completion of cell division is repressed and two daughter cells are linked by longer cell bridge in perturbed cells. W7 treatment during cytokinesis also results in unfinished cytokinesis and stopped G1 phase. These results suggest that calmodulin activity is required for centriole repositioning and can affect the completion of cytokinesis and cell cycle progression.

Anaphase↗

PubMed2005

Treatment of Epstein-Barr virus--associated lymphoproliferative disorder (EBV-PTLD) and pure red cell aplasia (PRCA) with Rituximab following unrelated cord blood transplantation: a case report and literature review.

OBJECTIVE: We report the first case of EBV-PTLD and pure red cell aplasia (PRCA) after an unrelated cord blood transplant in China, who was successfully treated with Rituximab. METHODS: Case report and literature review. RESULTS: A 5-year-old girl with CML underwent a major ABO-incompatible HLA-identical unrelated cord blood transplantation (U-CBT) in January 2003. The post transplant course was complicated by PRCA. She presented on day +75 with fever, followed by rapid enlargement of tonsils, and a cluster of lymph nodes in the cervical and submandibular regions. A cervical lymph node biopsy revealed the histopathologic findings consistent with PTLD. The immunoblasts were shown to contain EBV viral genomic DNA by PCR, and immunocytochemistry study for the latent membrane protein 1 (LMP-1) and in situ hybridization for Epstein-Barr encoded RNAs1 (EBER1) were both positive. She responded rapidly to Rituximab and achieved complete resolution of clinical findings and symptoms of both EBV-PTLD and PRCA. CONCLUSION: EBV-PTLD may occur with increasing frequency due to the increasing numbers of transplant recipients, transplant physician should be aware of this life-threatening complication. Rituximab alone may be an effective therapeutic strategy for patients who develop EBV-PTLD and PRCA after U-CBT.

ABO Blood-Group System↗

PubMed2005

Fabrication of nanoelectrodes for neurophysiology: cathodic electrophoretic paint insulation and focused ion beam milling.

The fabrication and characterization of tungsten nanoelectrodes insulated with cathodic electrophoretic paint is described together with their application within the field of neurophysiology. The tip of a 127 mum diameter tungsten wire was etched down to less than 100 nm and then insulated with cathodic electrophoretic paint. Focused ion beam (FIB) polishing was employed to remove the insulation at the electrode's apex, leaving a nanoscale sized conductive tip of 100-1000 nm. The nanoelectrodes were examined by scanning electron microscopy (SEM) and their electrochemical properties characterized by steady state linear sweep voltammetry. Electrode impedance at 1 kHz was measured too. The ability of a 700 nm tipped electrode to record well-isolated action potentials extracellularly from single visual neurons in vivo was demonstrated. Such electrodes have the potential to open new populations of neurons to study.

Journal Article↗

PubMed2005

Efficacy, tolerability and pharmacokinetics of two nelfinavir-based regimens in human immunodeficiency virus-infected children and adolescents: pediatric AIDS clinical trials group protocol 403.

INTRODUCTION: Few combinations of highly active antiretrovirals have been studied in nucleoside reverse transcription inhibitor (NRTI)-experienced, human immunodeficiency virus (HIV)-infected children. We tested the efficacy, tolerability and pharmacokinetics of 2 combination therapies containing an NRTI, protease inhibitors +/- a nonnucleoside reverse transcription inhibitor (NNRTI). METHODS: This was a phase II, randomized, multicenter study. Forty-one children and youths between 5 months and 21 years with prior NRTI and no prior NNRTI or protease inhibitor experience received either nelfinavir (NFV) 30 mg/kg twice daily (bid), ritonavir (RTV) 400 mg/m bid and buffered didanosine (ddI) 240 mg/m daily (arm A) or NFV 50-55 mg/kg bid, nevirapine (NVP) 120 mg/m bid and stavudine (d4T) 1 mg/kg bid (arm B). Patients were evaluated clinically for 48 weeks after initiation of therapy. Intensive pharmacokinetic sampling occurred after 4 weeks of therapy. RESULTS: : The proportion of children with HIV-1 RNA < or =400 copies/mL and on randomized treatment at 48 weeks was 65% among children assigned NFV + RTV + ddI versus 28% among those assigned NFV + NVP + d4T (P = 0.039). No significant difference in median CD4% change from baseline to week 48 was found (3% versus 1%). No significant differences in safety or tolerability between children randomized to NFV + RTV + ddI versus NFV + NVP + d4T were identified. However, a trend toward a higher rate of permanent discontinuation of study treatment was noted among children assigned to NFV + NVP + d4T compared with NFV + RTV + ddI [7 of 20 (35%) versus 2 of 21 (10%); P = 0.12]. NFV pharmacokinetic measurements were not statistically different between the treatment groups, yet exposure to the NFV metabolite, M8, was significantly higher in subjects receiving RTV. The pharmacokinetics for NVP, RTV and d4T were similar to those of previously reported data. CONCLUSION: : Combination therapy containing NFV + RTV + ddI appears more efficacious in NRTI-experienced children than a regimen containing NFV + NVP + d4T. Differences in tolerability between the 2 treatment groups were not identified. Systemic exposure of these drugs was similar to that reported in other HIV-infected children and adults.

Adolescent↗

PubMed2005

Inhibition of protein-tyrosine phosphatases stimulates insulin secretion in pancreatic islets of diabetic Goto-Kakizaki rats.

OBJECTIVES: Because increased expression of protein tyrosine phosphatases in the pancreatic islets may contribute to impaired insulin secretion in diabetes, we studied the effects of the phosphatase inhibitor peroxovanadate (pV) in islets of spontaneously diabetic Goto-Kakizaki (GK) and control Wistar rats. METHODS: Insulin release and glucose use were studied in isolated islets of GK and control rats. RESULTS: Insulin release from isolated GK rat islets at 3.3 and 16.7 mmol/L glucose was enhanced by pV in a dose-dependent manner (0.1-1 mmol/L). This was partly in contrast to the effect of pV in Wistar rat islets, where insulin response to 16.7 mmol/L glucose was inhibited by 0.01-0.1 mmol/L of the compound. In GK rat islets, pV was a strong initiator of insulin release and also had some potentiating effect on glucose-stimulated insulin secretion, whereas in Wistar rat islets, pV only had an initiating, and lacked potentiating, effect. The PI3K inhibitor wortmannin suppressed pV-induced insulin release at 3.3 mmol/L but not at 16.7 mmol/L glucose in both GK and Wistar rat islets. The modulatory effects by pV on insulin release were not related to effects by the compound on islet glucose metabolism. CONCLUSIONS: Our findings suggest that impaired insulin secretion in GK rat islets is accounted for, at least partly, by increased protein-tyrosine phosphatase activity in B cells.

Androstadienes↗

PubMed2005

Development and psychometric testing of the EverCare Nurse Practitioner Role and Activity Scale (ENPRAS).

PURPOSE: To develop and test an instrument measuring the frequency of the performance of role activities by EverCare nurse practitioners (NPs), who provide primary care to nursing home residents. DATA SOURCES: One hundred thirty-one EverCare Nurse Practitioner Role and Activity Scale (ENPRAS) activities were identified through telephone interviews (n= 11), participant observation (n= 5), and a focus group (n= 4). CONCLUSIONS: Two content validity tests (n= 11; n= 15) (Content Validity Index > or = .78 for all retained items) and internal consistency reliability testing (n= 127; Cronbach's alpha = .78-.96) yielded 99 activities arranged in six role subscales-Collaborator, Clinician, Care Manager/Coordinator, Counselor, Communicator/Cheerleader, and Coach/Educator. IMPLICATIONS FOR PRACTICE: The ENPRAS can be used to measure similarities and differences in NP practice activities performed by EverCare NPs working at different EverCare program sites and to compare practice activities performed by EverCare NPs and other NPs. The EverCare program is sponsored by United Health Care, which leads the field in collaborative NP/MD primary care in nursing homes. Future studies should be directed toward testing the generalizability of the ENPRAS with NPs working in other collaborative models, as well as NPs in noncollaborative models of care delivery in the long-term care setting.

Adult↗

PubMed2005

Dietary arginine supplementation attenuates renal damage after relief of unilateral ureteral obstruction in rats.

BACKGROUND: Progression of renal injury after relief of unilateral ureteral obstruction (UUO) has been demonstrated. Nitric oxide (NO) may be an effective intervention due to its vasodilatory, antifibrotic, and anti-apoptotic effects. Herein, we used dietary L-arginine (ARG) supplementation in a UUO relief model. METHODS: This study comprised group 1, control (no treatment). All other rats were subject to 3-day UUO, which was then relieved, and the rats maintained for 7 additional days. Group 2, no additional treatment; group 3, L-ARG; group 4, L-NAME, NO synthase inhibitor; group 5, ARG and L-NAME. Urinary NO(2/3) was quantified. GFR and ERPF were measured at day 10. Interstitial fibrosis and fibroblast expression, macrophage infiltration, tubular apoptosis, and proliferation, NOS expression, and the levels of tissue TGF-beta were evaluated. RESULTS: Urinary NO(2/3) was significantly increased by ARG treatment and decreased by L-NAME. GFR and ERPF measured 7 days following relief were not significantly different in the previously obstructed kidneys (POK) of groups 2 and 3. L-NAME significantly reduced GFR and ERPF in the POK. ARG significantly reduced apoptosis, macrophage infiltration, and fibroblast expression in the POK. L-NAME exacerbated the effects on apoptosis and fibroblasts. Fibrosis was minimal in groups 1 through 3, but was significantly increased by L-NAME. ARG did not affect renal NOS expression and tissue TGF-beta1 levels. CONCLUSION: Dietary ARG supplementation during UUO relief did not improve ERPF or GFR. However, renal damage, including fibrosis, apoptosis, and macrophage infiltration was significantly improved by ARG treatment. This suggests that increasing NO availability could be beneficial in the setting of UUO relief.

Animals↗

PubMed2005

Synthesis of linoleoyl disaccharides through lipase-catalyzed condensation and their surface activities.

Monolinoleoyl trehalose, maltose and cellobiose were synthesized by Candida antarctica lipase-catalyzed condensation in an organic solvent with a low water content. The use of a mixture of pyridine and tert-butanol as the reaction medium resulted in a high product concentration on the order of mmol/l for the synthesis of linoleoyl trehalose and maltose. The highest product concentration was achieved with the 0.4 volumetric fraction of pyridine. Linoleoyl cellobiose was also synthesized although its concentration was approximately one tenth the concentrations of linoleoyl trehalose and maltose. The surfactant properties of linoleoyl trehalose, maltose and cellobiose were measured. Among the esters, linoleoyl trehalose showed the strongest surface activity.

Biotechnology↗

PubMed2005

Comparative proteome analysis of breast cancer and normal breast.

Breast cancer is a leading cause of death for women. The underlying molecular mechanism is still not well understood. In this study, two-dimensional gel electrophoresis combined with mass spectrometry was used to analyze changes in the proteome of infiltrating ductal carcinoma compared to normal breast tissue. Ten sets of two-dimensional gels per experimental condition were analyzed and more than 500 spots each were detected. This revealed 39 spots for which expression in breast cancer cells were reproducibly altered more than twofold compared to normal controls (p < 0.01). These spots represented 25 different proteins after identification using the database search after mass spectrometry, comprising cell defense proteins, enzymes involved in glycolytic energy metabolism and homeostasis, protein folding and structural proteins, proteins involved in cytoskeleton and cell motility, and proteins involved in other functions. In addition, 28 nondifferentially expressed proteins with different functions were also mapped and identified, which might help to establish a two-dimensional gel electrophoresis reference map of human breast cancer. Our study shows that proteomics offers a powerful methodology to detect the proteins that show different expression patterns in breast cancer tissue and may provide an accurate molecular classification. The differentially expressed proteins may be used as potential candidate markers for diagnostic purposes or for determination of tumor sensitivity to therapy. The functional implications of the identified proteins are discussed.

Biomarkers, Tumor↗

PubMed2005

Environmental mycological study and allergic respiratory disease among tobacco processing workers.

This study presents the results of an investigation of respiratory symptoms, lung function, chest X-ray examinations, analysis of specific IgE antibodies and skin prick tests to fungi on 130 tobacco-processing workers and 112 control workers. Industrial hygiene survey and environmental mycological studies were also performed. The average dust concentrations ranged from 13.76 to 29.55 mg/m(3) in the tobacco processing workshops. Also, the numbers of fungi colonies in the processing environments were much higher than those in the control environments. The prevalences of chronic respiratory or nasal symptoms in exposed workers were significantly higher than those in control workers (p<0.05 or p<0.01). The prevalences of lung function abnormalities in the exposed workers were significantly higher than those in control workers (p<0.05). The positive prevalences of specific IgE reactions to fungi (26.92% for A.fumigatus and 51.54% for Rhizopus nigricans) in exposed workers were also significantly higher than those in control workers (p<0.01). The positive prevalences of the skin prick test showed that 18.46% of the exposed workers were positive to A. fumigatus and 23.85% were positive to Rhizopus nigricans. Our results suggested that tobacco processing workers may develop respiratory diseases related to tobacco dust and we consider that fungi might be one of the allergens causing allergic respiratory or nasal diseases in tobacco processing workers.

Adult↗

PubMed2005

Hypermethylation of the TPEF/HPP1 gene in primary and metastatic colorectal cancers.

The role of promoter methylation in the process of cancer cell metastasis has, however, not yet been studied. Recently, methylation of the TPEF (transmembrane protein containing epidermal growth factor and follistatin domain) gene was reported in human colon, gastric, and bladder cancer cells. Using the Methylight assay, TPEF/HPP1 gene methylation was assessed in primary colorectal cancers (n = 47), matched normal colon mucosa, as well as in the liver metastasis of 24 patients with colorectal cancer, and compared to the methylation status of the TIMP-3, APC, DAPK, caveolin-2, and p16 genes. TPEF was frequently methylated in primary colorectal cancers (36 of 47) compared to the normal colon mucosa (1 of 21) (P < .0001), and TPEF mRNA expression in colon cancer cell lines was restored after treatment with 5-aza-2'-deoxycytidine. The p16 and APC genes were also frequently methylated in primary colorectal cancers (P < .02) compared to the normal colon mucosa. Interestingly, promoter methylation was significantly more frequent in proximal, nonrectal cancers (P < .05). Furthermore, a high degree of methylation of the TPEF gene was also observed in liver metastasis (19 of 24). In summary, we observed frequent TPEF methylation in primary colorectal cancers and liver metastases, indicating that epigenetic alterations are not only present in the early phases of carcinogenesis, but are also common in metastatic lesions. The high frequency of TPEF methylation in this series of colorectal cancers underscores the importance of epigenetic changes as targets for the development of molecular tests for cancer diagnosis.

Adult↗