A Comprehensive Study of the Association between LEPR Gene rs1137101 Variant and Risk of Digestive System Cancers.

Objective: The leptin receptor, encoded by the LEPR gene, is involved in tumorigenesis. A potential functional variant of LEPR, rs1137101 (Gln223Arg), has been extensively investigated for its contribution to the risk of digestive system (DS) cancers, but results remain conflicting rather than conclusive. Here, we performed a case-control study and subsequent meta-analysis to examine the association between rs1137101 and DS cancer risk. Methods: A total of 1,727 patients with cancer (gastric/liver/colorectal: 460/480/787) and 800 healthy controls were recruited. Genotyping of rs1137101 was conducted using a polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) assay and confirmed using Sanger sequencing. Twenty-four eligible studies were included in the meta-analysis. Results: After Bonferroni correction, the case-control study revealed that rs1137101 was significantly associated with the risk of liver cancer in the Hubei Chinese population. The meta-analysis suggested that rs1137101 is significantly associated with the risk of overall DS, gastric, and liver cancer in the Chinese population. Conclusion: The LEPR rs1137101 variant may be a genetic biomarker for susceptibility to DS cancers (especially liver and gastric cancer) in the Chinese population.

An Investigation of the Effects of B7-H4 Gene rs10754339 and miR-125a Gene rs12976445 on Cancer Susceptibility.

Objective: To investigate the effects of the B7-H4 gene rs10754339 and miR-125a gene rs12976445 on cancer susceptibility through a case-control study and meta-analysis. Methods: A total of 1,490 cancer patients (lung/gastric/liver/: 550/460/480) and 800 controls were recruited in this case-control study. The meta-analysis was performed by pooling the data from previous related studies and the present study. Results: The results of this study showed that in the Hubei Han Chinese population, the rs10754339 gene was significantly associated with the risk of lung and gastric cancer but not liver cancer, and the rs12976445 gene was significantly associated with the risk of lung cancer but not liver or gastric cancer. The meta-analysis results indicated that rs10754339 and rs12976445 contributed to cancer susceptibility in the Chinese population and also revealed a significant association between rs10754339 and breast cancer risk, as well as between rs12976445 and lung cancer risk. Conclusion: The B7-H4 gene rs10754339 and miR-125a gene rs12976445 may be the potential genetic markers for cancer susceptibility in the Chinese population, which should be validated in future studies with larger sample sizes in other ethnic populations.

Nanoparticle delivery of stable miR-199a-5p agomir improves the osteogenesis of human mesenchymal stem cells via the HIF1a pathway.

Elucidating the regulatory mechanisms of osteogenesis of human mesenchymal stem cell (hMSC) is important for the development of cell therapies for bone loss and regeneration. Here we showed that hsa-miR-199a-5p modulated osteogenic differentiation of hMSCs at both early and late stages through HIF1a pathway. hsa-miR-199a expression was up-regulated during osteogenesis for both of two mature forms, miR-199a-5p and -3p. Over-expression of miR-199a-5p but not -3p enhanced differentiation of hMSCs in vitro, whereas inhibition of miR-199a-5p reduced the expression of osteoblast-specific genes, alkaline phosphatase (ALP) activity, and mineralization. Furthermore, over-expression of miR-199a enhanced ectopic bone formation in vivo. Chitosan nanoparticles were used for delivery of stable modified hsa-miR-199a-5p (agomir) both in vitro and in vivo, as a proof-of-concept for stable agomir delivery on bone regeneration. The hsa-mir199a-5p agomir were mixed with Chitosan nanoparticles to form nanoparticle/hsa-mir199a-5p agomir plasmid (nanoparticle/agomir) complexes, and nanoparticle/agomir complexes could improve the in vivo regeneration of bone. Further mechanism studies revealed that hypoxia enhanced osteogenesis at early stage and inhibited osteogenesis maturation at late stage through HIF1a-Twist1 pathway. At early stage of differentiation, hypoxia induced HIF1a-Twist1 pathway to enhance osteogenesis by up-regulating miR-199a-5p, while at late stage of differentiation, miR-199a-5p enhanced osteogenesis maturation by inhibiting HIF1α-Twist1 pathway.

An epigenetic regulator: methyl-CpG-binding domain protein 1 (MBD1).

DNA methylation is an important form of epigenetic regulation in both normal development and cancer. Methyl-CpG-binding domain protein 1 (MBD1) is highly related to DNA methylation. Its MBD domain recognizes and binds to methylated CpGs. This binding allows it to trigger methylation of H3K9 and results in transcriptional repression. The CXXC3 domain of MBD1 makes it a unique member of the MBD family due to its affinity to unmethylated DNA. MBD1 acts as an epigenetic regulator via different mechanisms, such as the formation of the MCAF1/MBD1/SETDB1 complex or the MBD1-HDAC3 complex. As methylation status always changes along with carcinogenesis or neurogenesis, MBD1 with its interacting partners, including proteins and non-coding RNAs, participates in normal or pathological processes and functions in different regulatory systems. Because of the important role of MBD1 in epigenetic regulation, it is a good candidate as a therapeutic target for diseases.

A miR-199a/miR-214 self-regulatory network via PSMD10, TP53 and DNMT1 in testicular germ cell tumor.

It was previously demonstrated that microRNA-199a (miR-199a) was down-regulated in testicular germ cell tumor (TGCT) partially caused by hypermethylation of its promoter. miR-199a is encoded by two loci in the human genome, miR-199a-1 on chromosome (Chr) 19 and miR-199a-2 on Chr 1. Both loci encode the same miR-199a. Another microRNA, microRNA-214 (miR-214), also locates on Chr 1. Previous study revealed that it is co-transcribed with miR-199a-2. However, the biological significance of the co-expression of miR-199a and miR-214 remains largely unknown. In this study, we determined that miR-199a and miR-214 were concordantly expressed in NT2 cells and TGCT patient tissues. After 5-aza treatment, miR-199-3p/5p and miR-214 expression was significantly increased. Silencing of DNMT1with siRNA restored the expression of miR-199a and miR-214, accompanied by de-methylation of the promoters of miR-199a-1/2. TP53 down-regulated the expression of DNMT1 in NT2 cells and overexpression of TP53 restored the expression of miR-199-3p/5p and miR-214. In addition, silencing of PSMD10 up-regulated the expression of TP53, while miR-214 over-expression resulted in PSMD10 down-regulation and TP53 up-regulation. Collectively, our findings highlighted a miR-199a/miR-214/PSMD10/TP53/DNMT1 self-regulatory network, which might be a potential therapeutic target in the treatment of TGCT.

The de novo DNA methyltransferase DNMT3A in development and cancer.

DNA methylation, one of the best-characterized epigenetic modifications, plays essential roles in development, aging and diseases. The de novo DNA methyltransferase DNMT3A is responsible for the establishment of de novo genomic DNA methylation patterns and, as such, involved in normal development as well as in many diseases including cancer. In recent years, our understanding of this important protein has made significant progress, which was facilitated by stunning development in the analysis of the DNA methylome of multiple organs and cell types. In this review, recent developments in the characterization of DNMT3A were discussed with special emphasis on the roles of DNMT3A in development and cancer.

microRNA-199a-3p, DNMT3A, and aberrant DNA methylation in testicular cancer.

It was previously demonstrated that miR-199a was downregulated in testicular germ cell tumor (TGCT), probably due to hypermethylation of its promoter. Further study found that re-expression of miR-199a in testicular cancer cells (NT2) led to suppression of cell growth, cancer migration, invasion and metastasis. More detailed analyses showed that these properties of miR-199a could be assigned to miR-199a-5p, one of its two derivatives. The biological role of the other derivative, miR-199a-3p in TGCT, remains largely uncharacterized. In this report, we identified DNA (cytosine-5)-methyltransferase 3A (DNMT3A), the de novo methyltransferase, as a direct target of miR-199a-3p using a 3'-UTR reporter assay. Transient expression of miR-199a-3p in NT2 cells led to decrease, while knocking down of miR-199a-3p in a normal human testicular cell line (HT) led to elevation, of DNMT3A2 (DNMT3A gene isoform 2) mRNA and protein levels. In clinical samples, DNMT3A2 was significantly overexpressed in malignant testicular tumor, and the expression of DNMT3A2 was inversely correlated with the expression of miR-199a-3p. However, DNMT3A did not affect miR-199a expression in NT2 cells. Further characterization of miR-199a-3p revealed that it negatively regulated DNA methylation, partly through targeting DNMT3A. Overexpression of miR-199a-3p restored the expression of APC and MGMT tumor-suppressor genes in NT2 cells by affecting DNA methylation of their promoter regions. Our studies demonstrated the deregulation of miR-199a-3p expression in TGCT may provide novel mechanistic insights into TGCT carcinogenesis and suggested a potentially therapeutic use of synthetic miR-199a-3p oligonucleotides as effective hypomethylating compounds in the treatment of TGCT.

Aberrant DNA methylation in human cancers.

DNA methylation, one of the best-characterized epigenetic modifications, plays essential roles in diseases, including human cancers. In recent years, our understanding on DNA methylation with human cancers has made significant progress, which was facilitated by stunning development in the analysis of the human methylome of multiple cancer types. In this review, recent developments in the characterization of aberrant DNA methylation involved in human cancers development were discussed with special emphasis on the mechanisms of aberrant DNA methylation in human cancers. We also summarize the recent treatment strategy for human cancers with de-methylation drugs.

[Study on alternative methods for the acute oral toxicity in detection of chemicals].

OBJECTIVE: To evaluate three alternative methods for LD50 test-Fixed Dose Procedure (FDP), the Acute Toxic Class Method (ATC) and Up and Down Procedure (UDP). METHODS: Female SD rats (8-12 weeks of age, 160-200 g) were used. Three alternative methods from OECD were applied to assess 22 chemicals (10 cosmetic raw materials and 12 raw materials of personal and home care products). The toxicity ranking for tested chemicals was established according to Globally Harmonized System (GSH). The results LD50 test were compared for the consistency and correlation between alternative methods and traditional test. RESULTS: For cosmetic raw materials, the concordance rate of the three alternative methods was 80% (8/10); for raw material of personal and home care products, the concordance rates of FDP, ATC and UDP was 91.7% (11/12), 75.0% (9/12) and 83.0% (10/12), respectively. The number of animals required in three alternative methods was significantly lower than that in traditional test (P < 0.05), but the time required in three alternative methods was significantly higher than that in traditional test (P < 0.05). CONCLUSIONS: High consistency and correlation were found between each alternative method and LD50 test. FDP may be more potential when applied to assess acute oral toxicity of cosmetic raw materials.

The histone deacetylase 4/SP1/microrna-200a regulatory network contributes to aberrant histone acetylation in hepatocellular carcinoma.

UNLABELLED: As an important epigenetic mechanism, histone acetylation modulates the transcription of many genes and plays important roles in hepatocellular carcinoma (HCC). Aberrations in histone acetylation have been observed in HCC, but the factors that contribute to the aberrations have not been fully elucidated. MicroRNAs (miRNAs), which are noncoding RNAs that regulate gene expression, are involved in important epigenetic mechanisms. In this study, we determined that miR-200a and the level of histone H3 acetylation at its promoter were reduced in human HCC tissues in comparison with adjacent noncancerous hepatic tissues. Furthermore, our results suggested that the histone deacetylase 4 (HDAC4) inhibited the expression of miR-200a and its promoter activity and reduced the histone H3 acetylation level at the mir-200a promoter through a Sp1-dependent pathway. Interestingly, we observed that the miR-200a directly targeted the 3'-untranslated region of the HDAC4 messenger RNA and repressed expression of HDAC4. Therefore, miR-200a ultimately induced its own transcription and increased the histone H3 acetylation level at its own promoter. Through targeting HDAC4, miR-200a also induced the up-regulation of total acetyl-histone H3 levels and increased the histone H3 acetylation level at the p21(WAF/Cip1) promoter. Finally, we determined that miR-200a inhibited the proliferation and migration of HCC cells in vivo and in vitro. CONCLUSION: Our findings suggest that the HDAC4/Sp1/miR-200a regulatory network induces the down-regulation of miR-200a and the up-regulation of HDAC4 in HCC. As a result, down-regulation of miR-200a enhances the proliferation and migration of HCC cells and induces aberrant histone acetylation in HCC. These findings highlight a potential therapeutic approach in targeting the HDAC4/Sp1/miR-200a regulatory network for the treatment of HCC.

[Application of flow cytometry on functional assessment of health food].

OBJECTIVE: To establish flow cytometry (FCM) methods and evaluate their application value for measuring the index for enhancing immune function of health food. METHODS: In mice experiment model, the dosage groups were respectively oral fed with three test substances according to 5, 10, 30 times of the recommended dose for human body; both the negative and positive control groups were fed with equivalence purified water once a day. The positive control was fed with 25 mg/kg body weight levamisole for 3 days before finishing the administration, and the immune two percent of sheep erythrocytes were administrated at the last day. In rats experiment model, the test substance was given by mixing feed according to 25 and 50 times of the recommended dose for human body. At the end of the experiment, indices below were simultaneously detected. (1) The classical indices included: spleen lymphocyte transformation test by using ConA (MTT assay); spleen NK cell activity test (LDH assay); delayed-type hypersensitivity test by using sheep erythrocyte (foot palm thickening) method and phagocytosis activity tested by mice peritoneal macrophages. (2) FCM indices included: T and B lymphocytes quantitating in mice peripheral blood, activated antigen expression level in the surface of T lymphocytes and NK cells and phagocytosis activity for fluospheres in mice peritoneal macrophages. RESULTS: (1) Compared with the negative control group, there were no significant differences in T and B lymphocytes proportion and the number of lymphocytes in mice peripheral blood after given 0.83, 1.67, 5.01 g/kg protein powder; (2) mice peripheral blood T lymphocyte sub-cluster CD(69)(+)/CD(3)(+) of 3.75, 7.50, 15.0 ml/kg bw Cen-Rong Cream groups were all significantly increased (P < 0.05), which were shown a good coherence with the classic test index; (3) mice peripheral blood NK cell sub-cluster CD(69)(+)/NKG2D(+) of 0.83, 1.67 g/kg protein powder groups were both significantly increased (P < 0.05), which was kept in good coherence with those of NK cell activity test (LDH assay); rats peripheral blood NK cell sub-cluster CD(161a+)/CD(25)(+) of 1.50 g/kg ganoderma lucidum and cordycepicmycelia group was significantly increased (P < 0.05); (4) the phagocytosis activity in mice peritoneal macrophages: there were no significant difference found between the controls and the dosage groups in the classic test. However, in the FCM test, the percentage of phagocytic cells of 0.15, 0.30, 0.90 g/kg ganoderma lucidum and cordycepicmycelia groups and the phagocytic index of 0.30, 0.90 g/kg were enhanced. CONCLUSION: It suggests that was shown in detecting and assessing enhancing immune function of health food the results tested by FCM were fairly consistent with those by using traditional methods, most of them would have higher sensitivity. It should be valuable to applying FCM in the measurement and assessment of enhancing immune function of health food and worth while to further study as to enlarging its application.