Laminin isoform expression in breast tumors

Certain laminins of vascular basement membranes have been identified in human breast tumors and brain gliomas that share the same β1 chain. These laminins are new carcinoma angiogenic markers and might represent potential targets for antiangiogenic therapy

Nanobiopolymer for Direct Targeting and Inhibition of EGFR Expression in Triple Negative Breast Cancer

Treatment options for triple negative breast cancer (TNBC) are generally limited to cytotoxic chemotherapy. Recently, anti-epidermal growth factor receptor (EGFR) therapy has been introduced for TNBC patients. We engineered a novel nanobioconjugate based on a poly(β-L-malic acid) (PMLA) nanoplatform for TNBC treatment. The nanobioconjugate carries anti-tumor nucleosome-specific monoclonal antibody (mAb) 2C5 to target breast cancer cells, anti-mouse transferrin receptor (TfR) antibody for drug delivery through the host endothelial system, and Morpholino antisense oligonucleotide (AON) to inhibit EGFR synthesis. The nanobioconjugates variants were: (1) P (BioPolymer) with AON, 2C5 and anti-TfR for tumor endothelial and cancer cell targeting, and EGFR suppression (P/AON/2C5/TfR), and (2) P with AON and 2C5 (P/AON/2C5). Controls included (3) P with 2C5 but without AON (P/2C5), (4) PBS, and (5) P with PEG and leucine ester (LOEt) for endosomal escape (P/mPEG/LOEt). Drugs were injected intravenously to MDA-MB-468 TNBC bearing mice. Tissue accumulation of injected nanobioconjugates labeled with Alexa Fluor 680 was examined by Xenogen IVIS 200 (live imaging) and confocal microscopy of tissue sections. Levels of EGFR, phosphorylated and total Akt in tumor samples were detected by western blotting

Screening for β-poly(l-malate) binding proteins by affinity chromatography

Poly(β-l-malic acid) is a cell type-specific polymer of myxomycetes (true slime molds) with the physiological role to organize mobility of certain proteins over the giant multinucleated plasmodia. We have developed an affinity chromatography employing 1,6-diamino-n-hexane–Sepharose-coupled poly(malic acid) to identify such proteins in cellular extracts of Physarum polycephalum. Molecular masses were measured by SDS–PAGE and non-denaturing PAGE after silver staining and/or Western blotting. Protein complexes/subunits were detected by 2-dimensional non-denaturing PAGE/SDS–PAGE. A simplified gel shift experiment displayed binding to fragmented calf thymus DNA. Nuclei were richest in poly(malate) binding proteins followed by cytoplasm and membranes. A protein of 370 kDa dissociated into 11 subunits of 11–29 kDa, indicative of a highly complex protein. This and other proteins displayed binding to nucleic acid in gel shift experiments. Poly(malate) is considered a structural and functional equivalent of long contiguous aspartate repeats in proteins of eukaryotes

Investigations on the antiproliferative effects of amino acid antagonists targeting for aminoacyl-tRNA synthetases. Part I. The antibacterial effect

Amino acid antagonists with proven or potentially inhibitory activities on aminoacyl-tRNA synthetases were tested for their antiproliferative effect against Escherichia coli B. The compds. 4- and 6-fluorotryptophan, 5-methyltryptophan, selenocysteine, and beta -(2-thienyl)alanine gave strong growth inhibition in minimal medium, which disappeared after the addn. of structurally related natural amino acids or in an enriched broth. The inhibitory effect on aminoacyl-tRNA synthetases and the minimal inhibitory concn. for growth inhibition in minimal medium could not be correlated

Investigations on the antiproliferative effects of amino acid antagonists targeting for aminoacyl-tRNA synthetases. Part III. Combination experiments

The combined effects of amino acid antagonists with proven or potential inhibitory activities on aminoacyl-tRNA synthetases were investigated on the murine leukemic cell line P388 D1. As the best result a summation of the antiproliferative effects was obsd. Combinations with established cytostatic agents like platinum complexes or other antitumor compds. also yielded partly additive effects. In expts. performed with asparaginase, L-aspartic acid-beta -hydroxamate gave synergistic growth inhibition of P388 D1 cells in vitro, which was reflected by additive effects against murine leukemia P388 in vivo

Stage specific expression of poly(malic acid)-affiliated genes in the life cycle of Physarum polycephalum. Spherulin 3b and polymalatase

Polymalic acid is receiving interest as a unique biopolymer of the plasmodia of mycetozoa and recently as a biogenic matrix for the synthesis of devices for drug delivery. The acellular slime mold Physarum polycephalum is characterized by two distinctive growth phases: uninucleated amoebae and multinucleated plasmodia. In adverse conditions, plasmodia reversibly transform into spherules. Only plasmodia synthesize poly(malic acid) (PMLA) and PMLA-hydrolase (polymalatase). We have performed suppression subtractive hybridization (SSH) of cDNA from amoebae and plasmodia to identify plasmodium-specific genes involved in PMLA metabolism. We found cDNA encoding a plasmodium-specific, spherulin 3a-like polypeptide, NKA48 (spherulin 3b), but no evidence for a PMLA-synthetase encoding transcript. Inhibitory RNA (RNAi)-induced knockdown of NKA48-cDNA generated a severe reduction in the level of PMLA suggesting that spherulin 3b functioned in regulating the level of PMLA. Unexpectedly, cDNA of polymalatase was not SSH-selected, suggesting its presence also in amoebae. Quantitative PCR then revealed low levels of mRNA in amoebae, high levels in plasmodia, and also low levels in spherules, in agreement with the expression under transcriptional regulation in these cells