In vitro and in vivo anti-tumor effect of Trichobakin fused with urokinase-type plasminogen activator ATF-TBK.

BACKGROUND: Trichobakin (TBK), a member of type I ribosome-inactivating proteins (RIPs), was first successfully cloned from Trichosanthes sp Bac Kan 8-98 in Vietnam. Previous study has shown that TBK acts as a potential protein synthesis inhibitor; however, the inhibition efficiency and specificity of TBK on cancer cells remain to be fully elucidated. METHODS AND RESULTS: In this work, we employed TBK and TBK conjugated with a part of the amino-terminal fragment (ATF) of the urokinase-type plasminogen activator (uPA), which contains the Ω-loop that primarily interacts with urokinase-type plasminogen activator receptor, and can be a powerful carrier in the drug delivery to cancer cells. Four different human tumor cell lines and BALB/c mice bearing Lewis lung carcinoma cells (LLC) were used to evaluate the role of TBK and ATF-TBK in the inhibition of tumor growth. Here we showed that the obtained ligand fused RIP (ATF-TBK) reduced the growth of four human cancer cell lines in vitro in the uPA receptor level-dependent manner, including the breast adenocarcinoma MDA-MB 231 cells and MCF7 cells, the prostate carcinoma LNCaP cells and the hepatocellular carcinoma HepG2 cells. Furthermore, the conjugate showed anti-tumor activity and prolonged the survival time of tumor-bearing mice. The ATF-TBK also did not cause the death of mice with doses up to 48 mg/kg, and they were not significantly distinct on parameters of hematology and serum biochemistry between the control and experiment groups. CONCLUSIONS: In conclusion, ATF-TBK reduced the growth of four different human tumor cell lines and inhibited lung tumor growth in a mouse model with little side effects. Hence, the ATF-TBK may be a target to consider as an anti-cancer agent for clinical trials.

Nanodiamond Solid-Phase Extraction and Triton X-114 Cloud Point Separation for Robust Fractionation and Shotgun Proteomics Analysis of the Human Serum Proteome.

Human serum is one of the most attractive specimens in biomarker research. However, its overcomplicated properties have hindered the analysis of low-abundance proteins by conventional mass spectrometry techniques. This work proposes an innovative strategy for utilizing nanodiamonds (NDs) in combination with Triton X-114 protein extraction to fractionate the crude serum to six pH-tuned fractions, simplifying the overall proteome and facilitating protein profiling with high efficiency. A total of 663 proteins are identified and evenly distributed among the fractions along with 39 FDA-approved biomarkers─a remarkable increase from the 230 proteins found in unfractionated crude serum. In the low-abundance protein section, 88 proteins with 7 FDA-approved biomarkers are detected─a marked increase from the 15 proteins (2 biomarkers) observed in the untreated sample. Notably, fractions at pH 11, derived from the aqueous phase of detergent separation, suggest potential applications in rapid and robust serum proteome analysis. Notably, by outlining the excellent properties of NDs for proteomic research, this work suggests a promising extraction protocol utilizing the great compatibility of NDs with streamlined serum proteomics and identifies potential avenues for future developments. Finally, we believe that this work not just improves shotgun proteomics but also opens up studies on the interaction between NDs and the human proteome. Data are available via ProteomeXchange with the identifier PXD029710.

The phosphoproteome of human Jurkat T cell clones upon costimulation with anti-CD3/anti-CD28 antibodies.

Phosphorylation is a reversible post-translational modification, playing a vital role in protein function. In T cells, protein phosphorylation is the key mechanism regulating T cell receptor-driven signaling pathways. In order to gain insights into the phosphoproteome evolution of T cell activation, we performed a large-scale quantitative phosphoproteomics study of Jurkat E6.1 (wild type) and Jurkat gamma1 (Phospholipase gamma1 null) cell clones upon costimulation with anti-CD3 and anti-CD28 antibodies at times ranging from 15min to as long as 120min. In total, we identified 5585 phosphopeptides belonging to 2008 phosphoproteins from both cell clones. We detected 130 and 114 novel phosphopeptides in Jurkat E6.1 and Jurkat gamma1 clones, respectively. A significantly lower number of proteins containing regulated phosphorylation sites were identified in Jurkat gamma1 in comparison to Jurkat E6.1, reflecting the vital role of Phospholipase gamma1 in T cell signaling. Several new phosphorylation sites from lymphocyte-specific protein tyrosine kinase (Lck) were identified. Of these, serine-121 showed significant changes in JE6.1 while only small changes in the Jgamma1 clone. Our data may contribute to the current human T cell phosphoproteome and provide a better understanding on T cell receptor signaling. Data are available via ProteomeXchange with identifier PXD002871.

Molecular cloning and characterization of a group II chaperonin delta-subunit from soybean.

Molecular characterization of plant group II chaperonin (CCT, c-cpn, or TriC) still remains elusive. By PCR-based cloning techniques using soybeans, we have made a successful attempt to clone a delta-subunit homologue of CCT (CCTdelta). This subunit is responsible for the binding of an in vivo substrate, alpha-actin, by assisting the correct folding of the cytoskeletal protein in mouse, and the occurrence of the subunit homologue in plant CCT was unclear. As the cloning strategy, a putative amino acid segment, NH(2)-Gly-Gly-Gly-Ala-Pro-Glu-COOH, which is tightly conserved in all known animal and yeast CCTdelta subunits, was chosen for designing a degenerate primer of the PCR-cloning. The resultant 1881-bp cDNA was found to have an open-reading frame of 533 amino acids with a calculated molecular mass of 57,677 Da and to share about 58-65% identity overall at the amino acid level with the corresponding subunits known to date. Using antibodies raised against Escherichia coli-produced soybean insoluble CCTdelta as a monitoring tool, we purified soybean CCT from the extract of its immature seeds. STEM images demonstrated that the molecular shape of soybean CCT is a double eight-membered ring, which resembles the known group II chaperonins. The CCT also reactivated a denatured firefly luciferase with a significant, but limited level of the native enzymic activity in an in vitro system. Northern blot analysis showed that soybean CCTdelta gene, which is intronless and composed of a small family, was only expressed at a very early stage of seed development of soybean.