Arginine-Glycine-Aspartic (RGD), is the specific recognition site of integrins with theirs ligands, and regulates cell-cell and cell-extracellular matrix interactions. The RGD motif can be combined with integrins overexpressed on the tumor neovasculature and tumor cells with a certain affinity, becoming the new target for imaging agents, and drugs, and gene delivery for tumor treatment. Further, RGD as a biomimetic peptide can also promote cell adherence to the matrix, prevent cell apoptosis and accelerate new tissue regeneration. Functionalizing material surfaces with RGD can improve cell/biomaterial interactions, which facilitates the generation of tissue-engineered constructs. This paper reviews the main functions and advantages of RGD, describes the applications of RGD in imaging agents, drugs, gene delivery for tumor therapy, and highlights the role of RGD in promoting the development of tissue engineering (bone regeneration, cornea repair, artificial neovascularization) in recent years.

Gastric carcinoma is one of the most common malignancies and the second most lethal cancer worldwide. The mechanisms underlying aggressiveness of gastric cancer still remain obscure. c-Myc promoter binding protein 1 (MBP-1) is a negative regulator of c-myc expression and ubiquitously expressed in normal human tissues. It is produced by alternative translation initiation of α-enolase gene. Both MBP-1 and α-enolase are involved in the control of tumorigenesis including gastric cancer. MicroRNAs (miRNAs) are involved in tumorigenesis and could have diagnostic, prognostic and therapeutic potential. In this study, whether miRNAs modulate tumorigenesis of gastric cancer cells through targeting MBP-1 was evaluated. We found that miR-363 targets 3'-untranslated region of human MBP-1/α-enolase messenger RNA. The exogenous miR-363 promotes growth, viability, progression, epithelial-mesenchymal transition and tumorsphere formation of SC-M1 gastric cancer cells through downregulation of MBP-1, whereas the knockdown of endogenous miR-363 suppresses tumorigenesis and progression of SC-M1 cells via upregulation of MBP-1. The miR-363/MBP-1 axis is also involved in the control of carcinogenesis in KATO III and SNU-16 gastric cancer cells. Furthermore, miR-363 induces the xenografted tumor growth and lung metastasis of SC-M1 cells through MBP-1 in vivo. Taken together, these results suggest that miR-363 plays an important role in the increment of gastric carcinogenesis via targeting MBP-1.

The 4-quinolones and their analogs are a heterogeneous group of biologically active compounds that have evolved in modern days to provide utilities at the forefront of antibiotic research. They have been used to combat Gram-negative or Gram-positive bacteria, suppress tumor growth, and treat many serious infections. These antimicrobial agents have also been used to promote apoptosis and DNA repair for the treatment of cancer. This review summarizes the experimental progress made in the synthetic development of various catalytic routes to preparing 4-quinolones and their analogs; discusses our current understanding of the reaction mechanisms involving biocatalytic synthesis, general catalytic synthesis, and asymmetric synthesis; and finally presents the future prospects of the emerging field.

To obtain robust and thermo-stable enzyme aggregates, p-benzoquinone was used as cross-linker and bovine serum albumin (BSA) as crowding macromolecules to prepare cross-linked enzyme aggregates (CLEAs) of lipase. Effects of cross-linking time and cross-linker content on the activity, thermal stability and characteristics of enzyme aggregates were examined carefully. It was observed that when the content of p-benzoquinone was 5 mM and amount of BSA was 125% of that of lipase (w/w), the specific activity of cross-linked co-aggregates of lipase and BSA was 79.8 U mg −1 , 2.44-fold of that of cross-linked enzyme aggregates of lipase without BSA. Moreover, after heat treatment for 96 h at 50 o C, the CLEAs prepared with this facile routine kept 75.18% of their initial activity, 5.01-fold more than that of the just CLEAs using glutaraldehyde. Furthermore, BSA macromolecules in lipase CLEAs enhanced the catalytic efficiency of free and just lipase CLEAs without BSA by 1.45 and 2.83 times, respectively. The proposed crosslinking technique would rank among the potential strategies for efficiently preparing robust and thermo-stable enzyme aggregates.

DNA family shuffling is a powerful method for enzyme engineering, which utilizes recombination of naturally occurring functional diversity to accelerate laboratory-directed evolution. However, the use of this technique has been hindered by the scarcity of family genes with the required level of sequence identity in the genome database. We describe here a strategy for collecting metagenomic homologous genes for DNA shuffling from environmental samples by truncated metagenomic gene-specific PCR (TMGS-PCR). Using identified metagenomic gene-specific primers, twenty-three 921-bp truncated lipase gene fragments, which shared 64 -99% identity with each other and formed a distinct subfamily of lipases, were retrieved from 60 metagenomic samples. These lipase genes were shuffled, and selected active clones were characterized. The chimeric clones show extensive functional and genetic diversity, as demonstrated by functional characterization and sequence analysis. Our results indicate that homologous sequences of genes captured by TMGS-PCR can be used as suitable genetic material for DNA family shuffling with broad applications in enzyme engineering.Many excellent examples of the application of directed evolution to a wide range of enzymes have clearly demonstrated its critical role in tailoring enzymes for industrial applications (1-4). Directed evolution mimics the processes of Darwinian evolution in a test tube, combining random mutagenesis and/or recombination with screening or selection for enzyme variants that have the desired properties (1). Directed evolution through random mutagenesis of a single starting sequence can result in significant improvement toward the required function. However, this strategy has the disadvantage of having to screen an extremely high number of candidates to find the rare positive mutants that are needed as the genetic material for DNA shuffling (5). A more potent directed evolution strategy is known as DNA family shuffling; it refers to the recombination of equivalent genes from natural homologous families rather than random mutagenesis of a single gene (6). This approach takes advantage of the fact that most of the deleterious mutations have long ago been removed by natural selection, while diverse function has been created by the positive mutation interchange. The reassortment of proven mutations yields a higher frequency of functional progeny sequences, and because multi-gene shuffling starts with more than one parental sequence, it accesses a broader range of progenitor combinations. These attributes make the approach more efficient, reducing loss-of-function mutations dramatically so that fewer progeny molecules need to be screened to discover superior performers (7-9).Although DNA family shuffling has the above-mentioned advantages over random mutagenesis, there are only dozens of published reports using it, unlike the thousands published that use random mutagenesis. The modest number of published cases of DNA family shuffling is indicative of its limitation: reliance on natural ...