Anti-tumor Effect of Ginkgo biloba Exocarp Extracts on B16 Melanoma Bearing Mice Involving P I3K/Akt/HIF-1α/VEGF Signaling Pathways.

The objective of this study is to investigate the anti-tumor effect of Ginkgo biloba exocarp extracts (GBEE) on B16 melanoma bearing mice and its related molecular mechanisms. The B16-F10 melanoma solid tumor model was established in C57BL/6J mice. The tumor-bearing mice were treated with GBEE (50, 100, 200 mg/kg), taking cis-Dichlorodiamineplatinum (Ⅱ) (DDP, 3 mg/kg) as positive control and normal saline (NS) as model control. After 17 days of administration, the transplanted tumors was stripped and weighed, and the inhibition rate was calculated. Quantitative Reverse Transcription Polymerase chain reaction (qRT-PCR), Western Blot and immunohistochemistry were applied to detect mRNA and protein levels of related factors in B16 transplanted tumor tissues. The results indicated that GBEE (50, 100, 200 mg/kg) inhibited the growth of B16 transplanted solid tumor in C57BL/6J mice. Meanwhile, it inhibited the expression of CD34 and reduced microvessel density (MVD) in a dose-dependent manner. Moreover, GBEE dose-dependently down-regulated the mRNA and protein levels of hypoxia inducible factor-1α (HIF-1α), vascular endothelial growth factor (VEGF), and vascular endothelial growth factor receptor 2 (VEGFR2). The phosphoinositide 3-kinase (PI3K) and protein kinase B (Akt) proteins were not changed obviously, but the protein levels of p-PI3K and p-Akt were down-regulated. Overall, the inhibitory effect of GBEE on the growth of B16 melanoma transplant tumor in mice is related to inhibiting angiogenesis, and the mechanism involves the regulation of PI3K/Akt/ HIF-lα/VEGF signaling pathway.

Increased Expression of PHGDH and Prognostic Significance in Colorectal Cancer.

Phosphoglycerate dehydrogenase (PHGDH) plays an essential role in cancer-specific metabolic reprogramming. It has been reported as a putative metabolic oncogene in several types of human malignant tumors, such as breast cancer and melanoma. To date, PHGDH expression in colorectal cancer (CRC) as well as its association with clinicopathological characteristics and prognostic implication remain undetermined. In this study, we determined the PHGDH protein expression using tissue microarray immunohistochemistry (TMA-IHC) on 193 pairs of formalin-fixed, paraffin-embedded specimens of CRC and adjacent tissues, 25 chronic colitis, 41 low-, and 19 high-grade intraepithelial neoplasia specimens, and we also determined PHGDH mRNA level using quantitative reverse transcription PCR (qRT-PCR) on additional 23 pairs of fresh CRC tissues and adjacent tissues. We found that both PHGDH mRNA and protein was highly expressed in tumor tissues in comparison with matched adjacent non-tumor tissues, and high PHGDH protein expression was correlated with advanced TNM stage (P = .038) and larger tumor (P = .001). Multivariate Cox regression analysis showed that PHGDH protein expression (HR = 2.285, 95% CI = 1.18 to 4.41, P = .014), tumor differentiation (HR = .307, 95% CI = .154 to 0.609, P = .001), and TNM stage (HR = 1.791, 95% CI = 1.125 to 2.85, P = .014) were independent prognostic factors in CRC. Kaplan-Meier survival curves and log rank test showed that high PHGDH protein expression contributed to poor outcome in CRC patients (P < .001). In conclusion, these results suggest that assessment of PHGDH expression could be useful in identifying a high-risk subgroup of CRC.

Insight into the Interaction of Graphene Oxide with Serum Proteins and the Impact of the Degree of Reduction and Concentration.

As novel applied nanomaterials, both graphene oxide (GO) and its reduced form (rGO) have attracted global attention, because of their excellent properties. However, the lack of comprehensive understanding of their interactions with biomacromolecules highly limits their biomedical applications. This work aims to initiate a systematic study on the property changes of GO/rGO upon interaction with serum proteins and on how their degree of reduction and exposure concentration affect this interaction, as well as to analyze the possible biomedical impacts of the interaction. We found that the adsorption of proteins on GO/rGO occurred spontaneously and rapidly, leading to significant changes in size, zeta potential, and morphology. Compared to rGO, GO showed a higher ability in quenching intrinsic fluorescence of serum proteins in a concentration-dependent manner. The protein adsorption efficiency and the types of associated proteins varied, depending on the degree of reduction and concentration of graphene. Our findings indicate the importance of evaluating the potential protein adsorption before making use of GO/rGO in drug delivery, because the changed physicochemical properties after protein adsorption will have significant impacts on safety and effectiveness of these delivery systems. On the other hand, this interaction can also be used for the separation, purification, or delivery of certain proteins.

Ilexgenin A induces B16-F10 melanoma cell G1/S arrest in vitro and reduces tumor growth in vivo.

The present study aimed to investigate the anti-tumor activity of Ilexgenin A in B16-F10 murine melanoma and to evaluate its effect on the production of tumor-associated inflammatory cytokines. In vitro, our study showed that Ilexgenin A inhibited the proliferation of B16-F10 murine melanoma cells in a dose- and time-dependent manner, and this effect could be ascribed to the arrest of the cell cycle at G0/G1. In vivo, we evaluated the anti-tumor activity of Ilexgenin A in a tumor-bearing mouse model. The results showed that Ilexgenin A reduced the tumor weight by 51.13% (p<0.01). The Ilexgenin A treatment groups showed no apparent side effects during the treatment period. In addition, a histological analysis revealed that Ilexgenin A changed the cell morphology, and induced large areas of necrosis that correlated with a reduction in tumor size. The detection of inflammatory cytokines indicated that the IL-6 level decreased (p<0.001) and the TNF-α level increased (p<0.01) in mice treated with Ilexgenin A. Ilexgenin A also inhibited the IL-6 production of macrophages stimulated by melanoma conditioned medium (MCM) significantly (p<0.001). Importantly, Ilexgenin A dramatically prolonged survival time (p<0.001). In conclusion, Ilexgenin A could be regarded as a promising agent for the treatment of melanoma; it exerts anti-melanoma activity by arresting the cell cycle at G0/G1 and regulating IL-6 and TNF-α production.

[Construction of a yeast two-hybrid cDNA library from the human testis].

OBJECTIVE: To construct a human testis cDNA library for yeast two-hybrid screening. METHODS: Human normal testis mRNA was purified from total RNA, and ds cDNA was synthesized and amplified using primers SMART III and CDS III oligo (dT) as the base of recombination. The purified PCR products and linearized plasmid pGADT7-Rec were co-transformed into the competent yeast Y187 and recombined by yeast homologous recombinase in the yeast cells to form an active cyclic plasmid. All the clones growing on the SD/-Leu plates were harvested to constitute a human testis cDNA library. RESULTS: We constructed a human testis cDNA library with high multiplication and adequate capacity, from which 2.0 x 10(6) recombinants were obtained. The amplified PCR fragments were between 0.3 kb and 4.0 kb in length. CONCLUSION: The yeast two-hybrid cDNA library of human testis was successfully constructed by the Clontech SMART method, which has prepared a ground for further studies on the molecular mechanism of spermatogenesis.

Lentivirus-mediated overexpression of microRNA-199a inhibits cell proliferation of human hepatocellular carcinoma.

microRNA-199a (miR-199a) is a highly conserved miRNA, always deregulated in numerous human tumors. The results of microarray analysis indicated that miR-199a was frequently downregulated in hepatocellular carcinoma (HCC). The expression levels of miR-199a in 11 pairs of matched HCC neoplastic and adjacent non-neoplastic tissues, 5 HCC cell lines and liver cell line L02 were examined by quantitative real-time PCR analysis. We found miR-199a was significantly down-regulated in HCC tissues when compared with pair-matched adjacent non-tumor tissues. We also found the expression level of miR-199a was also substantially decreased in several human HCC cell lines including SMMC-7721, BEL-7402, BEL-7701, MHCC97H, and HepG2. To investigate the role of miR-199a in tumorigenesis, we developed a lentiviral vector for the expression of pre-miR-199a (Lenti-miR-199a). Lenti-miR-199a inhibited HCC cell proliferation in vitro and in vivo. Compared to parental cells or cells transfected with a control vector, the overexpression of microRNA-199a in the HCC cell lines HepG2 stably was showed to reduce cell proliferation in vitro and in vivo. Luciferase reporter assay revealed the regulation of miR-199a on 3'-UTR of HIF-1α. Further investigation confirmed that miR-199a significantly reduced the endogenous protein level of HIF-1α in hypoxia. MiR-199a inhibits cell proliferation in vitro and in vivo partly through down-regulation of HIF-1α in human HCC. Thus, these studies provide an important new insight into the pathogenesis of human HCC and it may open a new perspective for the development of effective gene therapy for human HCC.

Genetic polymorphism analysis of killer cell immunoglobulin-like receptor genes in the Chinese Uygur population.

Human killer cell immunoglobulin-like receptors are expressed in natural killer cells and subsets of T lymphocytes. They regulate these cells upon interaction with human leukocyte antigen class I molecules and other ligands presented by target cells. KIR gene frequencies and haplotype distributions have been shown to differ significantly between populations from different geographical regions and ethnic origins, which relates to functional variations in the immune response. We have investigated KIR gene frequencies and genotype diversities of 15 KIR genes (KIR2DL1, 2DL2, 2DL3, 2DL4, 2DL5, 2DS1, 2DS2, 2DS3, 2DS4, ID, 2DS5, 3DL1, 3DL2, 3DL3, 3DS1) and two pseudogenes (KIR3DP1 and 2DP1) in 120 unrelated healthy individuals of the Uygur population living in the Xinjiang autonomous region of China. All individuals were typed positive for the four framework loci KIR3DL3, 2DL4, 3DL2 and KIR3DP1, while activating genes (KIR2DS1, 2DS2, 2DS3, 2DS5 and KIR3DS1) indicated some variation in this population. KIR3DS1 was found in a higher frequency in the studied population than in other groups from China. Linkage disequilibrium among KIR genes displayed a wide range. χ(2) analysis, conducted among non-ubiquitous genes, based on the KIR gene frequency data from our study population and previously published population data, revealed significant differences in the KIR2DL1, 2DL2, 2DL3, 2DL5, 3DL1, 2DS1, 2DS2, 2DS3, 2DS5, and 3DS1 genes. A neighbor-joining phylogenic tree, built using the observed carrier frequencies data of 13 KIR loci (KIR2DL1, 2DL2, 2DL3, 2DL4, 2DL5, 3DL1, 3DL2, 3DL3, 2DS1, 2DS2, 2DS3, 2DS5, and 3DS1), showed relationships between the population studied and other previously reported populations. The present study can therefore be valuable for enriching the ethnical gene information resources of the KIR gene pool, for population origin studies and for KIR-related clinical practice.

[Screening PIAS2-interacting proteins in the mouse using the yeast two-hybrid system].

OBJECTIVE: To screen and identify PIAS2-interacting proteins from the mouse spermatogonial cDNA library using the yeast two-hybrid system, and to investigate the action mechanism of PIAS2 in spermatogenesis. METHODS: With pGBKT7-PIAS2 as a bait plasmid, the positive clones interacting with pGBKT7-PIAS2 were screened from the mouse spermatogonial cDNA library, the inserted fragments were sequenced and underwent bioinformatic analysis, and their interaction was verified using the yeast two-hybrid system. RESULTS: Through screening, sequencing, homology analysis and yeast two-hybrid verification, we obtained 8 different candidate proteins interacting with PIAS2, including Cyfip2, Psmb3, Nmel, nischarin, Ints10, Nsun5, Gnb211 and Ndufaf3. CONCLUSION: Eight different genes were successfully obtained using the yeast two-hybrid system, and their encoding proteins interacted with PIAS2, which might be related with male fertility regulation. Our findings have offered some new clues to the action mechanism of PIAS2 in spermatogenesis.

Inhibition of connective tissue growth factor overexpression decreases growth of hepatocellular carcinoma cells in vitro and in vivo.

BACKGROUND: We have previously found that connective tissue growth factor (CTGF) is highly expressed in a rat model of liver cancer. Here, we examined expression of CTGF in human hepatocellular carcinoma (HCC) cells and its effect on cell growth. METHODS: Real-time PCR was used to observe expression of CTGF in human HCC cell lines HepG2, SMMC-7721, MHCC-97H and LO2. siRNA for the CTGF gene was designed, synthesized and cloned into a Plk0.1-GFP-SP6 vector to construct a lentivirus-mediated shRNA/CTGF. CTGF mRNA and protein expression in HepG2 cells treated by CTGF-specific shRNA was evaluated by real-time PCR and Western blotting. 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay was utilized to evaluate the growth effect, and a colony formation assay was used for observing clonogenic growth. In vivo, tumor cell proliferation was evaluated in a nude mouse model of xenotransplantation. Statistical significance was determined by t test for comparison between two groups, or analysis of variance (ANOVA) for multiple groups. RESULTS: Immunohistochemical staining of CTGF was seen in 35 of 40 HCC samples (87.5%). CTGF was overexpressed 5-fold in 20 HCC tissues, compared with surrounding non-tumor liver tissue. CTGF mRNA level was 5 - 8-fold higher in HepG2, SMMC-7721 and MHCC-97H than in LO2 cells. This indicated that the inhibition rate of cell growth was 43% after knockdown of CTGF expression (P < 0.05). Soft agar colony formation assay showed that siRNA mediated knockdown of CTGF inhibited colony formation in soft agar of HepG2 cells (P < 0.05). The volume of tumors from CTGF-shRNA-expressing cells only accounted for 35% of the tumors from the scrambled control-infected HepG2 cells (P < 0.05). CONCLUSIONS: CTGF was overexpressed in human HCC cells and downregulation of CTGF inhibited HCC growth in vitro and in vivo. Knockdown of CTGF may be a potential therapeutic strategy for treatment of HCC.

Elimination of the mycotoxin citrinin production in the industrial important strain Monascus purpureus SM001.

The application of the high-producing pigments industrial strain Monascus purpureus SM001 has been greatly limited by the synchronous production of mycotoxin citrinin. Here we have tried both traditional mutagenesis and metabolic engineering methods to eliminate the production of citrinin. Traditional chemical and physical mutagens were applied to induce mutagenesis, and a bio-screening method based on the antibacterial activity of citrinin against Bacillus subtilis was designed to select mutants. Among the resulting four citrinin-free mutants, only mutant MU2411 can maintain the similar pigments yield. A binary vector system was constructed and successfully disrupted the polyketide synthase gene pksCT in M. purpureus SM001 through the Agrobacterium tumefaciens-mediated transformation. The resulting citrinin-free DeltapksCT mutants maintained the same level of pigments yield. The established Monascus genetic system was comprehensively evaluated and showed high efficiency and specificity, which provides us a potential approach to manipulate and improve industrial Monascus strains.