[Effect of Erchen Decoction on liver mitochondrial function by inhibiting mTORC1/SREBP1/CAV1 pathway in mice with high-fat diet].

This study aims to investigate the effect of Erchen Decoction(ECD) on liver mitochondrial function in mice with a high-fat diet and its possible mechanism. A total of sixty C57BL/6J mice were randomly divided into a normal group, high-fat group, ECD group, mTORC1 activator(MHY) group, ECD+MHY group, and polyene phosphatidyl choline(PPC) group, with 10 rats in each group. The normal group was given a normal diet, and the other groups were fed a high-fat diet for 20 weeks. At the 17th week, the ECD group and ECD+MHY group were given ECD(8.7 g·kg~(-1)) daily, and the PPC group was given PPC(0.18 g·kg~(-1)) daily, while the remaining groups were given normal saline(0.01 mL·g~(-1)) daily for four weeks. In the 19th week, the MHY group and ECD+MHY group were injected intraperitoneally with MHY(5 mg·kg~(-1)) every other day for two weeks. During the experiment, the general conditions of the mice were observed. The contents of triglyceride(TG) and total cholesterol(TC) in serum were measured. Morphological changes in liver tissue were examined through HE and oil red O staining. The content of adenosine triphosphate(ATP) was determined using chemiluminescence, and mitochondrial membrane potential was assessed using a fluorescence probe(JC-1). Western blot was performed to detect the expression of rapamycin target protein complex 1(mTOR1), ribosomal protein S6 kinase B1(S6K), sterol regulatory element binding protein 1(SREBP1), and caveolin 1(CAV1). RESULTS:: revealed that compared with the normal group, the mice in the high-fat group exhibited significant increases in body weight and abdominal circumference(P<0.01). Additionally, there were significant increases in TG and TC levels(P<0.01). HE and oil red O staining showed that the boundaries of hepatic lobules were unclear; hepatocytes were enlarged, round, and irregularly arranged, with obvious lipid droplet deposition and inflammatory cell infiltration. The liver ATP content and mitochondrial membrane potential decreased significantly(P<0.01). The expression of p-mTOR, p-S6K, and n-SREBP1 increased significantly(P<0.01), while the expression of CAV1 decreased significantly(P<0.01). Compared with the high-fat group, the body weight and TG content of mice in the ECD group and PPC group decreased significantly(P<0.05). Improvements were observed in hepatocyte morphology, lipid deposition, and inflammatory cell infiltration. Furthermore, there were significant increases in ATP content and mitochondrial membrane potential(P<0.05 or P<0.01). The expression of p-mTOR, p-S6K, and n-SREBP1 decreased significantly in the ECD group(P<0.01), while CAV1 expression increased significantly(P<0.01). However, the indices mentioned above did not show improvement in the MHY group. When the ECD+MHY group was compared with the MHY group, there were significant reductions in body weight and TG contents(P<0.05). The morphological changes of hepatocytes, lipid deposition, and inflammatory cell infiltration were recovered. Moreover, there were significant increases in liver ATP content and mitochondrial membrane potential(P<0.05 or P<0.05). The expression of p-mTOR, p-S6K, and n-SREBP1 decreased significantly(P<0.01), while CAV1 expression increased significantly(P<0.01). In conclusion, ECD can improve mitochondrial function by regulating the mTORC1/SREBP1/CAV1 pathway. This mechanism may be involved in the resolution of phlegm syndrome and the regulation of lipid metabolism.

Regulation of Fatty Acid Metabolism and Inhibition of Colorectal Cancer Progression by Erchen Decoction.

Erchen decoction (ECD) is a traditional Chinese prescription widely used in the treatment of various diseases such as obesity, fatty liver, diabetes, and hypertension. In this study, we investigated the effect of ECD on fatty acid metabolism in a colorectal cancer (CRC) mouse model fed a high-fat (HF) diet. The HF-CRC mouse model was established by azoxymethane (AOM)/dextran sulphate sodium (DSS) combined with a high-fat diet. Mice were then gavaged with ECD. Change in the body weight was recorded every two weeks for 26 weeks. Changes in blood glucose (GLU), total cholesterol (TC), total triglycerides (TG), and C-reactive protein (CRP) were measured. Colorectal tissues were collected to observe changes in colorectal length and tumorigenesis. Hematoxylin-eosin (HE) staining and immunohistochemical staining were performed to observe changes in intestinal structure and inflammatory markers. Fatty acids and the expression of related genes in colorectal tissues were also studied. ECD gavage inhibited HF-induced weight gain. CRC induction and HF diet intake resulted in increased GLU, TC, TG, and CRP, where ECD gavage reduced these elevated indicators. ECD gavage also increased colorectal length and inhibited tumorigenesis. HE staining revealed that ECD gavage suppressed inflammatory infiltration of colorectal tissues. ECD gavage suppressed the fatty acid metabolism abnormalities caused by HF-CRC in colorectal tissues. Consistently, ECD gavage lowered ACSL4, ACSL1, CPT1A, and FASN levels in colorectal tissues. Conclusions. ECD inhibited HF-CRC progression through the regulation of fatty acid metabolism.

The involvement of Notch1 signaling pathway in mid-aged female rats under chronic restraint stress.

Women are vulnerable to adverse stress events, especially during perimenopause. Substantial evidence has associated the impaired neuronal plasticity with abnormal behaviors under stressful conditions in animals. The Notch signaling pathway is critical for neuronal plasticity in the structure and function of brain areas. In this study, the mid-aged female rats were subjected to chronic restraint stress(CRS) in combination with isolated rearing for 6 weeks. The behavior tests and HPA activity were conducted to evaluate the model. The mRNA and protein levels of Notch1 signaling related genes in the hippocampus(HIP) and prefrontal cortex(PFC) were analyzed by RT-qPCR and western blotting. The promoter methylation levels were measured by bisulfite sequencing PCR analysis. CRS induced depression-like and anxiety-like behaviors in mid-aged stressed females, as shown by decreased locomotor activity, sucrose consumption and increased HPA activity. Moreover, after CRS, the rats exhibited decreased mRNA and protein levels in Jagged1, Notch1 and Hes5 in the HIP and Notch1, Hes1 and Hes5 in the PFC. However, there were no significant promotor methylation changes between the stressed and control female rats. These findings suggest that Notch1 signaling pathway may contribute to the behavioral changes following CRS in mid-aged female rats and the upstream cause of the gene expression changes needs to be further investigated.

Clinically applicable 53-Gene prognostic assay predicts chemotherapy benefit in gastric cancer: A multicenter study.

BACKGROUND: We previously established a 53-gene prognostic signature for overall survival (OS) of gastric cancer patients. This retrospective multi-center study aimed to develop a clinically applicable gene expression detection assay and to investigate the prognostic value of this signature. METHODS: A TCGA gastric adenocarcinoma cohort (TCGA-STAD) was used for comparing 53-gene signature with other gene signatures. A high-throughput mRNA hybridization gene expression assay was developed to quantify the expression of 53-genes in formalin-fixed paraffin-embedded tissues of 540 patients enrolled from three hospitals. 180 patents were randomly selected from two hospitals to build a prognostic prediction model based on the 53-gene signature using leave-p-out (one-third out) cross-validation method together with Cox regression and Kaplan-Meier analysis, and the model was assessed on three validation cohorts. FINDINGS: In the evaluation phase, studies based on TCGA-STAD showed that the 53-gene signature was significantly superior to other three prognostic signatures and was independent of TCGA molecular subtypes and clinical factors. For clinical validation and utility, the prognostic scores were generated using the newly developed assay, which was reliable and sensitive, in 100 sampling training sets and were significantly associated with OS in 100 sampling validation sets. The scores were significantly associated with OS in three independent and combined validation cohorts, and in patients with stages II and III/IV. The multivariate Cox regression demonstrated that the prognostic power of the score was independent of clinical factors, consistent with those findings in the TCGA dataset. Finally, patients with good prognostic scores exhibited significantly a better 5-year OS rate from adjuvant FOLFOX chemotherapy after surgery than from other chemotherapies. INTERPRETATION: The 53-gene prognostic score system is clinically applicable for predicting the OS of patients independent of clinical factors in gastric cancers, which could also be a promising predictive biomarker for FOLFOX regimen. FUNDING: Chinese National Science and Technology, National Natural Science Foundation and Natural Science Foundation of Jiangsu Province.

WITHDRAWN: The Involvement of Notch1 Signaling Pathway in Mid-aged Female Rats under Chronic Restraint Stress.

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Erchen Decoction Ameliorates Lipid Metabolism by the Regulation of the Protein CAV-1 and the Receptors VLDLR, LDLR, ABCA1, and SRB1 in a High-Fat Diet Rat Model.

Lipid metabolism disorder is a common metabolic disorder characterized by abnormal lipid levels in blood. Erchen decoction (ECD) is a traditional Chinese medicine prescription, which is used for the treatment of diseases caused by retention of phlegm dampness. It has been reported to ameliorate the disorder of lipid metabolism. The aim of the present study was to investigate the effects and underlying mechanisms of ECD in lipid metabolism disorder induced by a high-fat diet (HFD) in rats. ECD (4.35g/kg/d) and atorvastatin (10mg/kg/d, positive control) were orally administered to HFD-fed rats for four weeks. The parameters, food, water consumption, body weight, body length, liver, and visceral fat weight and the content of serum lipids and lipid transporters were assessed. The effects of ECD on the mRNA and protein expression levels of lipid transport factors were measured by real-time PCR and western blotting. The present study demonstrated that ECD improved the disorders of serum lipid and lipid transporters in HFD-fed rats, TG (0.70±0.08 mmol/L, p<0.01), LDL-C (1.50±0.19 mmol/L, p<0.01), LDL (1.38±0.21 mmol/L, p<0.05), and oxLDL (1.77±0.39 ng/mL, p<0.05) were downregulated, while HDL-C (0.87±0.13 mmol/L, p<0.01), FFA (0.62±0.13 mmol/L, p<0.05), HDL (38.8±4.0 mg/dL, p<0.05), and CETP (903.6±120.0 ng/mL, p<0.05) were upregulated. But ECD obviously had no effects on the indices food/water/energy intake, body/tissue (liver and fat) weight, and BMI (p>0.05). Concomitantly, ECD reversed the abnormal expressions of those lipid transport factors in the liver and visceral fat.

The association of CYP2C9 gene polymorphisms with colorectal carcinoma in Han Chinese.

BACKGROUND: Cytochrome P450 (CYP) 2C9 is an important enzyme involved in xenobiotics metabolism. This study investigated the association of CYP2C9 gene coding region polymorphisms with colorectal cancer (CRC) in Chinese Han population. METHODS: Four hundred and eighty-three healthy controls and 286 sporadic CRC patients participated in this study. Direct sequencing was used to identify the sequence polymorphisms. RESULTS: We detected the significant association of 2 coding region SNPs, rs1057910 and rs1057911, of CYP2C9 with the risk of developing sporadic CRC for Han Chinese. These 2 SNPs showed a strong linkage disequilibrium (LD) (r(2)=0.97, D'=0.985). Significantly different minor allele frequencies were found for SNPs rs1057910 and rs1057911 between the cases (7% and 7.2%, respectively) and controls (3% and 2.9%, respectively) with adjusted P=0.0004 and 0.0002, respectively. Individuals heterozygous for rs1057910A/C or rs1057911A/T showed 2.589-fold (95% CI: 1.549-4.330) or 2.770-fold (95% CI 1.653-4.643) increased risk of developing sporadic CRC. We did not detect any homozygote minor allele carrier for either rs1057910 or rs1057911 in our study population. The CRC association appeared to be more evident for individuals over age 50 y, for men, and for rectum cancer site. CONCLUSION: There is an association of CYP2C9 coding region polymorphisms with the risk of developing CRC in Han Chinese after genotyping cases and controls recruited from different locations in China.

Observing the development of the temporomandibular joint in embryonic and post-natal mice using various staining methods.

The temporomandibular joint (TMJ) is a specialized synovial joint that is essential for the movement and function of the mammalian jaw. The TMJ develops from two mesenchymal condensations, and is composed of the glenoid fossa that originates from the otic capsule by intramembranous ossification, the mandibular condyle of the temporal bone and a fibrocartilagenous articular disc derived from a secondary cartilaginous joint by endochondral ossification. However, the development of the TMJ remains unclear. In the present study, the formation and development of the mouse TMJ was investigated between embryonic day 13.5 and post-natal day 180 in order to elucidate the morphological and molecular alterations that occur during this period. TMJ formation appeared to proceed in three stages: Initiation or blastema stage; growth and cavitation stage; and the maturation or completion stage. In order to investigate the activity of certain transcription factors on TMJ formation and development, the expression of extracellular matrix (ECM), sex determining region Y-box 9, runt-related transcription factor 2, Indian hedgehog homolog, Osterix, collagen I, collagen II, aggrecan, total matrix metalloproteinase (MMP), MMP-9 and MMP-13 were detected in the TMJ using in situ and/or immunohistochemistry. The results indicate that the transcription factors, ECM and MMP serve critical functions in the formation and development of the mouse TMJ. In summary, the development of the mouse TMJ was investigated, and the molecular regulation of mouse TMJ formation was partially characterized. The results of the present study may aid the systematic understanding of the physiological processes underlying TMJ formation and development in mice.

Effect of serum from postmenopausal women with osteoporosis exhibiting the Kidney-Yang deficiency pattern on bone formation in an hFOB 1.19 human osteoblastic cell line.

The aim of the present study was to investigate the underlying mechanism of the Kidney-Yang deficiency (KYD) pattern of osteoporosis in postmenopausal women of a certain age range by comparing the effect of serum from postmenopausal women with osteoporosis exhibiting the KYD pattern with that of serum from postmenopausal women without osteoporosis on bone formation in an hFOB 1.19 human osteoblastic cell line. A random selection of 30 female, postmenopausal volunteers aged 60-70 years, including 15 cases without osteoporosis and 15 cases with the KYD pattern of osteoporosis, were enrolled at the Physical Examination Center of the Second Affiliated Hospital of Fujian University of Traditional Chinese Medicine. Venous blood was extracted and the serum was separated. The hFOB 1.19 cells were treated with 10% KYD pattern-serum or control serum from postmenopausal women of the same age range without osteoporosis. It was found that the KYD pattern-serum significantly decreased the cell viability, activity of alkaline phosphatase and number of calcified nodules, as well as downregulated the expression of osteocalcin and osteoprotegerin (OPG) and upregulated that of receptor activator of nuclear factor κB ligand (RANKL) in the hFOB 1.19 cells. In addition, the present results showed that the concentrations of estradiol (E2), OPG and insulin-like factor-1 (IGF-1) in the KYD pattern-serum were lower than those in the control serum. In combination, these findings suggest that the downregulation of E2, OPG and IGF-1 in the KYD pattern-serum inhibits the OPG/RANKL system, leading to a decrease in bone formation in the hFOB 1.19 cells. This indicates that the alterations in E2, OPG and IGF-1 may account for the susceptibility of certain postmenopausal women to the KYD pattern of osteoporosis.

Erchen Decoction Prevents High-Fat Diet Induced Metabolic Disorders in C57BL/6 Mice.

Erchen decoction (ECD) is a traditional Chinese medicine prescription, which is used in the treatment of obesity, hyperlipidemia, fatty liver, diabetes, hypertension, and other diseases caused by retention of phlegm dampness. In this study we investigated the potential mechanism of ECD, using metabolism-disabled mice induced by high-fat diet. Body weight and abdominal circumference were detected. OGTT was measured by means of collecting blood samples from the tail vein. Blood lipid levels and insulin were measured using biochemical assay kit. Real-time PCR was used to measure the CDKAL1 gene expression and western blot was used to measure the protein expression. Through the research, it was found that ECD showed markedly lower body weight and abdominal circumference than those in the HFD group. Consistently, we observed that ECD significantly improved glucose tolerance, promoted the secretion of insulin and decreased the level of TG, TC level. Meanwhile, we observed significantly increased CDKAL1 mRNA and protein level in the ECD group. Therefore, we speculate that the potential molecular mechanism of ECD is to promote the CDKAL1 expression, ameliorate islet cell function, and raise insulin levels to regulate the metabolic disorder.

Gallic acid induces apoptosis and inhibits cell migration by upregulating miR-518b in SW1353 human chondrosarcoma cells.

Gallic acid (GA), a natural agent, is widely distri-buted in plants with a range of biological effects and has been of potential interest as anticancer agent. However, its effects on chondrosarcoma cell apoptosis are still undefined. In the present study, the possible mechanisms of GA-induced apoptosis were explored in SW1353 cells, a human chondrosarcoma cell line. Our results showed that GA inhibited cell viability dose- and time-dependently. Morphological examination of GA-treated cells exhibited the typical features of cell death, such as rounding up of the cells and cell shrinkage. Wound-healing assay indicated that GA inhibited the migratory abilities of SW1353 cells. Hoechst 33258 staining assay and Annexin V/PI staining assay exhibited apoptosis induction by GA. To determine the molecular mechanism of GA-induced apoptosis, the expression levels Bcl-2, Bax, caspase-3 and caspase-9 were determined in SW1353 cells treated with GA. We found that GA downregulated the expression of the anti-apoptotic protein Bcl-2, and upregulated the expression of the pro-apoptotic protein Bax, and the activation of caspase-3 and caspase-9. To identify the possible mechanisms, the changes of microRNA expression were tested using the miRCURY™ LNA expression array. It was observed that the miR-518b gene was upregulated in treated cells. Taken together, these data show that GA induces apoptosis and inhibits cell migration by upregulating miR-518b in SW1353 cells.

Chaihu-Shugan-San administration ameliorates perimenopausal anxiety and depression in rats.

Chaihu-Shugan-San (CSS) is a traditional Chinese herbal formula that is widely used for treating perimenopausal symptoms in China; however, its mechanisms remain unknown. The present study was designed to investigate potential CSS mechanisms in rats with unpredicted chronic mild stress (UCMS) and normally aging rats (52 weeks of age). We performed the sucrose consumption test along with the forced swimming test to confirm depression-like behavior and the open field test (OFT) to confirm anxiety-like behavior in the animals. In addition, we used an enzyme-linked immunosorbent assay to measure serum and hippocampal estradiol (E2) levels and a quantitative real-time polymerase chain reaction to assess hippocampal mRNA levels of estrogen receptors (ERs) α and ß as well as G protein-coupled receptor 30 (GPR30). We found that CSS administration resulted in a significant increase in the ratio of hippocampal ERα and ERß mRNA (ERα/ERß ratio) in UCMS rats (p<0.001). However, no significant changes were observed in E2 levels, ERα mRNA expression, and GPR30 mRNA expression. In contrast, changes in ERα/ERß mRNA ratio were sensitively associated with changes in mood states in the animal models. These findings suggest that enhancement of ERα/ERß ratio may play a role in the pharmacological mechanisms of CSS. Furthermore, this ratio can be employed as a potential index for evaluating mood states in animal models and can be considered as a therapeutic target for perimenopausal anxiety and depression in the future.

Tongue coating microbiome regulates the changes in tongue texture and coating in patients with post-menopausal osteoporosis of Gan-shen deficiency syndrome type.

Tongue inspection is a unique and important method of diagnosis in traditional Chinese medicine (TCM). It is a diagnostic approach which involves observing the changes in the tongue proper and tongue coating in order to understand the physiological functions and pathological changes of the body. However, the biological basis of TCM tongue diagnosis remains to be poorly understood and lacks systematic investigation at the molecular level. In this study, we evaluated the effects of tongue coating microbiome on changes in the tongue texture and coating in patients with post-menopausal osteoporosis (PMO) of Gan­shen deficiency syndrome type. Our aim was to delineate the mechanisms of tongue coating microbiome-induced changes in the tongue texture and coating by investigating the histomorphological changes and performing a bacterial analysis of the tongue coating. We found that the number of intermediate cells in the red tongue with a thin coating was higher, while the number of superficial cells in the red tongue with a thin coating was lower. The maturation value (MV) of tongue exfoliated cells in the red tongue with a thin coating decreased, compared with that in the pale red tongue with a thin white coating. Furthermore, the total bacterial count, oral streptococcus, Gram­positive (G+) and Gram­negative (G-) anaerobic bacteria in the red tongue with a thin coating was significantly decreased compared with the pale red tongue with a thin white coating. The results of ultrastructural examination demonstrated that the number of epithelial cells and bacteria in the red tongue with a thin coating decreased compared with that in the pale red tongue with a thin white coating. These observations indicate that the tongue coating microbiome may be an important factor contributing to changes in the tongue in patients with PMO of Gan­shen deficiency syndrome type.

Icariin promotes bone formation via the BMP-2/Smad4 signal transduction pathway in the hFOB 1.19 human osteoblastic cell line.

Icariin, the main active compound of the traditional Chinese medicine, Epimedium, is commonly used for the clinical treatment of osteoporosis. However, the precise molecular mechanism of the therapeutic effect of icariin has not been elucidated. The aim of this study was to examine the effect of icariin on cell viability, alkaline phosphatase (ALP) activity, the amount of calcified nodules, and to delineate the molecular mechanism of icariin-enhanced bone formation by investigating the expression of bone morphogenic protein-2 (BMP-2), Smad4, Cbfa1/Runx2, osteoprotegerin (OPG), receptor activator of nuclear factor κ-B ligand (RANKL) and the OPG/RANKL ratio in the hFOB 1.19 human osteoblastic cell line. We found that icariin significantly increased the cell viability, the activity of ALP and the amount of calcified nodules in the hFOB 1.19 cells. Furthermore, we observed that icariin upregulated the expression of BMP-2, Smad4, Cbfa1/Runx2, OPG, RANKL and the OPG/RANKL ratio. Our results indicate that icariin can modulate the process of bone formation via the BMP-2/Smad4 signal transduction pathway in hFOB 1.19 cells.

Single-nucleotide polymorphisms and haplotype of CYP2E1 gene associated with systemic lupus erythematosus in Chinese population.

INTRODUCTION: Cytochrome P-450 2E1 (CYP2E1) is an important member of the CYP superfamily, which is involved in the metabolism and activation of many low molecular weight toxic compounds. We tried to investigate the possible association of CYP2E1 tag single nucleotide polymorphisms (SNPs) with susceptibility to systemic lupus erythematosus (SLE) in a Chinese Han population. METHODS: The coding and flanking regions of the CYP2E1 gene were scanned for polymorphisms and tag SNPs were selected. A two-stage case-control study was performed to genotype a total of 876 SLE patients and 680 geographically matched healthy controls (265 cases and 288 controls in stage I and 611 cases and 392 controls in stage II). SLE associations of alleles, genotypes and haplotypes were tested by age and sex adjusted logistic regression. The gene transcription quantitation was carried out for peripheral blood mononuclear cell (PBMC) samples from 120 healthy controls. RESULTS: Tag SNP rs2480256 was found significantly associated with SLE in both stages of the study. The "A" allele was associated with slightly higher risk (odds ratio (OR) = 1.165, 95% confidence interval (CI) 1.073 to 1.265, P = 2.75E-4) and "A/A" genotype carriers were with even higher SLE risk (OR = 1.464 95% CI 1.259 to 1.702, P = 7.48E-7). When combined with another tag SNP rs8192772, we identified haplotype "rs8192772-rs2480256/TA" over presented in SLE patients (OR 1.407, 95% CI 1.182 to 1.675, P = 0.0001) and haplotype "TG" over presented in the controls (OR 0.771, 95% CI 0.667 to 0.890, P = 0.0004). The gene transcription quantitation analysis further proved the dominant effect of rs2480256 as the "A/A" genotype showed highest transcription. CONCLUSIONS: Our results suggest the involvement of CYP2E1 as a susceptibility gene for SLE in the Chinese population.

Quercetin-mediated apoptosis via activation of the mitochondrial-dependent pathway in MG-63 osteosarcoma cells.

Quercetin (a natural polyphenolic compound) is a polyphenolic flavonoid compound found in a variety of plants. It has been demonstrated to exert cytostatic activity against a variety of human cancer cell lines, including the human osteosarcoma cell line, MG-63. However, its effects on osteosarcoma cell apoptosis are still undefined. The present study was undertaken to examine the effect of quercetin on cell viability, apoptosis and mitochondrial membrane potential, and to determine the molecular mechanism of quercetin-induced apoptosis by investigating the expression of Bcl-2 family proteins (Bcl-2, Bax), cytochrome C, caspase-9 and caspase-3 in MG-63 cells. We found that quercetin suppressed the viability of MG-63 cells in a dose- and time- dependent manner. Furthermore, we observed that quercetin induced the loss of mitochondrial membrane potential, upregulated the expression of the proapoptotic proteins, Bax and cytochrome C, and activated caspase-9 and caspase-3, and downregulated the expression of antiapoptotic protein, Bcl-2. These data suggest that quercetin may induce apoptosis via the mitochondrial-dependent pathway in MG-63 cells.

Microsomal glutathione S-transferase gene polymorphisms and colorectal cancer risk in a Han Chinese population.

BACKGROUND AND AIMS: Glutathione S-transferases (GSTs) are phase II detoxification enzymes. Human GSTs have been classified into cytosolic, mitochondrial, and microsomal families. Several studies reported the association of colorectal cancer (CRC) risk with the genetic polymorphisms of cytosolic GSTs. The microsomal GSTs are structurally distinct but functionally similar to cytosolic GSTs; their association with CRC has not been reported. In this report, we summarized the result of a case-control study aimed at investigating the association of MGST1 gene locus polymorphisms with CRC risk among Han Chinese. PATIENT/METHODS: Three hundred and seventy-two healthy controls and 238 sporadic CRC patients participated in this study. DNA resequencing was conducted for the 3.4 kb genomic DNA region containing the promoter, exons, exon-intron junctions, and the 5' and 3' untranslated regions. RESULTS: We detected 13 single nucleotide polymorphisms (SNPs) including four novel SNPs not reported in database/literature. The gene shows a much higher nucleotide diversity than most human genes. The linkage and recombination analysis revealed 24 common haplotypes (13% > or = freq > or = 1%) and identified extensive intragenic recombination throughout the MGST1 locus (R = 81.8). Significant CRC association (P < or = 0.005) was not detected for each individual SNP. However, SNPs 102G>A and 16416G>A reached a marginal level of statistical significance with P values of 0.016 and 0.078, respectively. A combined genotype analysis detected a statistically significant CRC association for individuals carrying 102G>A/16416G>A (GG/GG) genotype (adjusted OR, 1.682; 95% confidence interval (CI), 1.177-2.404; P = 0.004). Consistent with the results of genotype analysis, the GG haplotype (102G>A/16416G>A) with two risk alleles was associated with a significantly higher CRC risk comparing with the haplotypes with one or no risk allele (adjusted OR 1.744; 95% CI 1.309-2.322; P = 0.0001). CONCLUSION: The results suggest that MGST1 polymorphisms may contribute to CRC risk among Han Chinese.