A miRNA Signature of Chemoresistant Mesenchymal Phenotype Identifies Novel Molecular Targets Associated with Advanced Pancreatic Cancer

In this study a microRNA (miRNA) signature was identified in a gemcitabine resistant pancreatic ductal adenocarcinoma (PDAC) cell line model (BxPC3-GZR) and this signature was further examined in advanced PDAC tumor specimens from The Cancer Genome Atlas (TCGA) database. BxPC3-GZR showed a mesenchymal phenotype, expressed high levels of CD44 and showed a highly significant deregulation of 17 miRNAs. Based on relevance to cancer, a seven-miRNA signature (miR-100, miR-125b, miR-155, miR-21, miR-205, miR-27b and miR-455-3p) was selected for further studies. A strong correlation was observed for six of the seven miRNAs in 43 advanced tumor specimens compared to normal pancreas tissue. To assess the functional relevance we initially focused on miRNA-125b, which is over-expressed in both the BxPC3-GZR model and advanced PDAC tumor specimens. Knockdown of miRNA-125b in BxPC3-GZR and Panc-1 cells caused a partial reversal of the mesenchymal phenotype and enhanced response to gemcitabine. Moreover, RNA-seq data from each of 40 advanced PDAC tumor specimens from the TCGA data base indicate a negative correlation between expression of miRNA-125b and five of six potential target genes (BAP1, BBC3, NEU1, BCL2, STARD13). Thus far, two of these target genes, BBC3 and NEU1, that are tumor suppressor genes but not yet studied in PDAC, appear to be functional targets of miR-125b since knockdown of miR125b caused their up regulation. These miRNAs and their molecular targets may serve as targets to enhance sensitivity to chemotherapy and reduce metastatic spread.     

Expression of POTE protein in human testis detected by novel monoclonal antibodies

The POTE gene family is composed of 13 highly homologous paralogs preferentially expressed in prostate, ovary, testis, and placenta. We produced 10 monoclonal antibodies (MAbs) against three representative POTE paralogs: POTE-21, POTE-2γC, and POTE-22. One reacted with all three paralogs, six MAbs reacted with POTE-2γC and POTE-22, and three MAbs were specific to POTE-21. Epitopes of all 10 MAbs were located in the cysteine-rich repeats (CRRs) motifs located at the N-terminus of each POTE paralog. Testing the reactivity of each MAb with 12 different CRRs revealed slight differences among the antigenic determinants, which accounts for differences in cross-reactivity. Using MAbs HP8 and PG5 we were able to detect a POTE-actin fusion protein in human testis by immunoprecipitation followed by Western blotting. By immunohistochemistry we demonstrated that the POTE protein is expressed in primary spermatocytes, implying a role in spermatogenesis.     

Copper(II) promoted imidazolidine ring formation and complexation: A unique reaction course

The reaction of Cu(II) ions with a sodium salt of new Schiff base ligand NaL¹, sodium N-2-methyl pyridine-2-imine benzoate, in alkaline medium produced an imine bond coupled ligand and a novel complex, Na₂[Cu(L³)₂], L³ = 2,5-di(2-benzoic acid)-4-(2-pyridine)-1-(2-methyl-2-pyridine)-imidazolidine. When the reduced form of the sodium salt of the Schiff base ligand, NaL², is employed, a simple hexacoordinated copper(II) complex, [Cu(L²)₂], [L²]⁻ = bis(N-(2-methylpyridine)-2-aminomethylbenzoate), was isolated. The compounds were characterized by spectroscopic methods and the molecular structures of [Cu(L²)₂] and Na₂[Cu(L³)₂] were determined by single-crystal X-ray diffraction methods. Reaction mechanism for the synthesis of, Na₂[Cu(L³)₂], copper(II) promoted imine bond coupling is proposed and discussed. The redox behavior of [Cu(L²)₂] and Na₂[Cu(L³)₂], studied using cyclic voltammetry and electron paramagnetic resonance spectroscopic methods, are also discussed.     

PATE gene clusters code for multiple, secreted TFP/Ly-6/uPAR proteins that are expressed in reproductive and neuron-rich tissues and possess neuromodulatory activity

We report here syntenic loci in humans and mice incorporating gene clusters coding for secreted proteins each comprising 10 cysteine residues. These conform to three-fingered protein/Ly-6/urokinase-type plasminogen activator receptor (uPAR) domains that shape three-fingered proteins (TFPs). The founding gene is PATE, expressed primarily in prostate and less in testis. We have identified additional human PATE-like genes (PATE-M, PATE-DJ, and PATE-B) that co-localize with the PATE locus, code for novel secreted PATE-like proteins, and show selective expression in prostate and/or testis. Anti-PATE-B-specific antibodies demonstrated the presence of PATE-B in the region of the sperm acrosome and at high levels on malignant prostatic epithelial cells. The syntenic mouse Pate-like locus encompasses 14 active genes coding for secreted proteins, which are all, except for Pate-P and Pate-Q, expressed primarily in prostate and/or testis. Pate-P and Pate-Q are expressed solely in placental tissue. Castration up-regulates prostate expression of mouse Pate-B and Pate-E, whereas testosterone ablates this induced expression. The sequence similarity between TFP/Ly-6/uPAR proteins that modulate activity of nicotinic acetylcholine receptors and the PATE (Pate)-like proteins stimulated us to see whether these proteins possess analogous activity. Pharmacological studies showed significant modulation of the nicotinic acetylcholines by the PATE-B, Pate-C, and Pate-P proteins. In concert with these findings, certain PATE (Pate)-like genes were extensively expressed in neuron-rich tissues. Taken together, our findings indicate that in addition to participation of the PATE (Pate)-like genes in functions related to fertility and reproduction, some of them likely act as important modulators of neural transmission.     

Molecular modeling of the ternary complex of Rusticyanin-cytochrome c4-cytochrome oxidase: an insight to possible H-bond mediated recognition and electron transfer reaction in T. ferrooxidans

The metabolism of Thiobacillus ferrooxidans involves electron transfer from the Fe+2 ions in the extracellular environment to the terminal oxygen in the bacterial cytoplasm through a series of periplasmic proteins like Rusticyanin (RCy), Cytochrome (Cyt c4), and Cytochrome oxidase (CcO). The energy minimization and MD studies reveal the stabilization of the three redox proteins in their ternary complex through the direct and water mediated H-bonds and electrostatic interaction. The surface exposed polar residues of the three proteins, i.e., RCy (His 143, Thr 146, Lys 81, Glu 20), Cyt c4 (Asp 5, 15, 52, Ser 14, Glu 61), and CcO (Asp 135, Glu 126, 140, 142, Thr 177) formed the intermolecular hydrogen bonds and stabilized the ternary complex. The oxygen (Oepsilon1) of Glu 126, 140, and 142 on subunit II of the CcO interact to the exposed side-chain and Ob atoms of the Asp 52 of Cyt c4 and Glu 20 and Leu 12 of RCy. The Asp 135 of subunit II also forms H-bond with the Nepsilon atom of Lys 81 of RCy. The Oepsilon1 of Glu 61 of Cyt c4 is also H-bonded to Ogamma atom of Thr 177 of CcO. Solvation followed by MD studies of the ternary protein complex revealed the presence of seven water molecules in the interfacial region of the interacting proteins. Three of the seven water molecules (W 79, W 437, and W 606) bridged the three proteins by forming the hydrogen bonded network (with the distances approximately 2.10-2.95 A) between the Lys 81 (RCy), Glu 61 (Cyt c4), and Asp 135 (CcO). Another water molecule W 603 was H-bonded to Tyr 122 (CcO) and interconnected the Lys 81 (RCy) and Asp 135 (CcO) through the water molecules W 606 and W 437. The other two water molecules (W 21 and W 455) bridged the RCy to Cyt c4 through H-bonds, whereas the remaining W 76 interconnected the His 53 (Cytc4) to Glu 126 (CcO) with distances approximately 2.95-3.0 A.     

Progressive decrease of phosphocreatine, creatine and creatine kinase in skeletal muscle upon transformation to sarcoma

In vertebrates, phosphocreatine and ATP are continuously interconverted by the reversible reaction of creatine kinase in accordance with cellular energy needs. Sarcoma tissue and its normal counterpart, creatine-rich skeletal muscle, are good source materials to study the status of creatine and creatine kinase with the progression of malignancy. We experimentally induced sarcoma in mouse leg muscle by injecting either 3-methylcholanthrene or live sarcoma 180 cells into one hind leg. Creatine, phosphocreatine and creatine kinase isoform levels decreased as malignancy progressed and reached very low levels in the final stage of sarcoma development; all these parameters remained unaltered in the unaffected contralateral leg muscle of the same animal. Creatine and creatine kinase levels were also reduced significantly in frank malignant portions of human sarcoma and gastric and colonic adenocarcinoma compared with the distal nonmalignant portions of the same samples. In mice, immunoblotting with antibodies against cytosolic muscle-type creatine kinase and sarcomeric mitochondrial creatine kinase showed that both of these isoforms decreased as malignancy progressed. Expressions of mRNA of muscle-type creatine kinase and sarcomeric mitochondrial creatine kinase were also severely downregulated. In human sarcoma these two isoforms were undetectable also. In human gastric and colonic adenocarcinoma, brain-type creatine kinase was found to be downregulated, whereas ubiquitous mitochondrial creatine kinase was upregulated. These significantly decreased levels of creatine and creatine kinase isoforms in sarcoma suggest that: (a) the genuine muscle phenotype is lost during sarcoma progression, and (b) these parameters may be used as diagnostic marker and prognostic indicator of malignancy in this tissue.     

A minimalistic tetrapeptide amphiphile scaffold for transmembrane pores with a preference for sodium

Synthetic channels or pores that are easy to synthesize, stable and cation-selective are extremely attractive for the development of therapeutics and materials. Herein, we report a pore developed from a small tetrapeptide scaffold that shows a preference for sodium over lithium/potassium. The sodium selectivity is attributed to the appended oligoether tail at the C-terminus. A peptide dimer is proposed as the predominant cation-transporting pore. Such pyridine containing stable pores can be potentially utilized for the pH modulated ion transport.     

Specific killing of HIV-infected lymphocytes by a recombinant immunotoxin directed against the HIV-1 envelope glycoprotein

BACKGROUND: 3B3 is a high-affinity anti-gp120 antibody that neutralizes a wide range of primary and laboratory isolates of HIV-1. The parental antibody was isolated from a combinatorial phage display library constructed from bone marrow RNA of an HIV-infected individual. We have generated a highly active immunotoxin using the 3B3 single-chain Fv (scFv) which can specifically kill lymphocytes infected by HIV-1. MATERIALS AND METHODS: We used recombinant DNA technology to clone the Fv fragment of 3B3 and produce a single-chain Fv (scFv). 3B3 scFv was then fused to a truncated version of Pseudomonas exotoxin A (PE38), giving rise to a recombinant immunotoxin 3B3(Fv)-PE38 that was expressed in E. coli and purified to near homogeneity. RESULTS: 3B3(Fv)-PE38 binds with the same affinity as the parental Fab antibody to the MN strain of gp120. The immunotoxin specifically kills a gp120-expressing transfected cell line and a chronically HIV-infected lymphocytic cell line. The immunotoxin is very stable at 37 degrees C, retaining 80% of its original activity after 24 hr. CONCLUSIONS: Potent immunotoxins such as 3B3(Fv)-PE38 could be utilized in combination with multidrug cocktails that limit viral replication to help reduce viral reservoirs in patients with AIDS.     

Subcellular compartmentalization of glutathione peroxidase 1 allelic isoforms differentially impact parameters of energy metabolism

Specific genetic variations in the gene for the selenium-containing antioxidant protein glutathione peroxidase 1 (GPX1) are associated with the risk of a variety of common diseases, including cancer, diabetes, and cardiovascular disorders. Two common variations have been focused upon, one resulting in leucine or proline at codon 198 and another resulting in 5, 6, or 7 alanine repeats were previously shown to affect the distribution of GPX1 between the cytoplasm and mitochondria. Human MCF7 cells engineered to exclusively express GPX1 with five alanine repeats at amino terminus and proline at codon 198 (A5P) and seven alanine repeats at amino terminus and leucine at codon 198 (A7L), as well as derivatives targeted to the mitochondria by the addition of a mitochondrial localization sequence (mA5P and mA7L) were used to assess the consequences of the expression of these proteins on the cellular redox state and bioenergetics. Ectopic expression of A5P and A7L reduced the levels of reactive oxygen species, and the mitochondrially targeted derivatives exhibited better activity in these assays. Bioenergetics and mitochondrial integrity were assessed by measuring mitochondrial membrane potential, oxygen consumption, adenosine triphosphate (ATP) levels, and the levels of lactate dehydrogenase. The results of these assays indicated distinctively, and sometimes opposing, patterns with regard to differences between the consequences of the expression of A5P, A7L, mA5P, and mA7L. These data provide new information on the consequences of differences in the primary structure and cellular location of GPX1 proteins and contribute to the understanding of how these effects might contribute to human disease.