Integrin-binding Protein Nischarin Interacts with Tumor Suppressor Liver Kinase B1 (LKB1) to Regulate Cell Migration of Breast Epithelial Cells

Biallelic inactivation of LKB1, a serine/threonine kinase, has been detected in 30% of lung adenocarcinomas, and inhibition of breast tumor growth has been demonstrated. We have identified the tumor suppressor, Nischarin, as a novel binding partner of LKB1. Our mapping analysis shows that the N terminus of Nischarin interacts with amino acids 44–436 of LKB1. Time lapse microscopy and Transwell migration data show that the absence of both Nischarin and LKB1 from an invasive breast cancer cell line (MDA-MB-231) enhances migration as measured by increased distance and speed of migrating cells. Our data suggest that this is a result of elevated PAK1 and LIMK1 phosphorylation. Moreover, the absence of Nischarin and LKB1 increased tumor growth in vivo. Consistent with this, the percentage of S phase cells was increased, as demonstrated by flow cytometry and enhanced cyclin D1. The absence of Nischarin and LKB1 also led to a dramatic increase in the formation of lung metastases. Our studies, for the first time, demonstrate functional interaction between LKB1 and Nischarin to inhibit cell migration and breast tumor progression. Mechanistically, we show that these two proteins together regulate PAK-LIMK-Cofilin and cyclin D1/CDK4 pathways.     

Synthesis and structure-activity relationship studies of cinnamic acid-based novel thiazolidinedione antihyperglycemic agents

A number of 2,4-thiazolidinedione derivatives of -phenyl substituted cinnamic acid were synthesized and studied for their PPAR agonist activity. The E-isomer of cinnamic acid, 11, showed moderate PPAR transactivation. The corresponding Z-isomer, 23, and double bond reduced derivative, 15, were found to be much less potent. Although the E-isomer showed a moderate PPAR gamma transactivation, it demonstrated a strong glucose-lowering effect in a genetic rodent model of diabetes. Results of pharmacokinetic, metabolism and permeability studies are consistent with 11 being an active prodrug with an active metabolite, 14, that has similar glucose lowering and PPAR gamma agonist properties.     

Sequence Analysis of 16S rRNA and secA Genes Confirms the Association of 16SrI‐B Subgroup Phytoplasma with Oil Palm (Elaeis guineensis Jacq.) Stunting Disease in India

During January 2010, severe stunting symptoms were observed in clonally propagated oil palm (Elaeis guineensis Jacq.) in West Godavari district, Andhra Pradesh, India. Leaf samples of symptomatic oil palms were collected, and the presence of phytoplasma was confirmed by nested polymerase chain reaction (PCR) using universal phytoplasma‐specific primer pairs P1/P7 followed by R16F2n/R16R2 for amplification of the 16S rRNA gene and semi‐nested PCR using universal phytoplasma‐specific primer pairs SecAfor1/SecArev3 followed by SecAfor2/SecArev3 for amplification of a part of the secA gene. Sequencing and BLAST analysis of the ～1.25 kb and ～480 bp of 16S rDNA and secA gene fragments indicated that the phytoplasma associated with oil palm stunting (OPS) disease was identical to 16SrI aster yellows group phytoplasma. Further characterization of the phytoplasma by in silico restriction enzyme digestion of 16S rDNA and virtual gel plotting of sequenced 16S rDNA of ～1.25 kb using iPhyClassifier online tool indicated that OPS phytoplasma is a member of 16SrI‐B subgroup and is a ‘Candidatus Phytoplasma asteris’‐related strain. Phylogenetic analysis of 16S rDNA and secA of OPS phytoplasma also grouped it with 16SrI‐B. This is the first report of association of phytoplasma of the 16SrI‐B subgroup phytoplasma with oil palm in the world.     

Antioxidant and cytotoxic activity of bioactive phenolic metabolites isolated from the yeast-extract treated cell culture of apple

Buds of in vitro-grown shoots of two purple-fleshed potato genotypes were successfully cryopreserved by encapsulation-vitrification (Encap-vitri) and droplet-vitrification (Drop-vitri). Optimal time durations of exposure to PVS2 for shoot regrowth of cryopreserved buds were 5–7 h and 6 h for ‘E03-2677’ and for ‘Blue Congo’, respectively, in Encap-vitri, and 30–50 min and 40 min for the former and the latter, respectively, in Drop-vitri. Higher rates of shoot regrowth were obtained in 1.5–2.0 mm-buds than in 1.0–1.4 mm-ones in Encap-vitri for ‘E03-2677’ and ‘Blue Congo’, while opposite results were found in Drop-vitri. In ‘Blue Congo’, only apical shoot tips survived and developed into shoots, with one shoot produced in one cryopreserved bud in Encap-vitri and Drop-vitri. In ‘E03-2677’, survival and shoot regrowth patterns were similar to those of ‘Blue Congo’ in Encap-vitri. However, both apical and axillary shoot tips survived and developed into two shoots in one bud in Drop-vitri. In ‘E03-2677’, histological observations revealed only apical shoot tips survived following Encap-vitri, while both apical and axillary shoot tips survived following Drop-vitri. Vegetative growth in shoots regenerated from Encap-vitri and Drop-vitri after 3 weeks of post-thaw culture was significantly lower than that from control, but markedly increased after 6 months of post-thaw culture. In both ‘E03-2677’ and ‘Blue Congo’, number of microtubers per shoot, per vessel and ≥3 mm in diameter were significantly greater in shoots regenerated from Encap-vitri than in those from the control. Assessments by ISSR and RAPD of genetic stability did not find any polymorphic bands in regenerants recovered from Encap-vitri and Drop-vitri. To the best of our knowledge, this is the first report on cryopreservation of purple-fleshed potato by vitrification-based procedures. Results reported here would provide valuable basic and technical information on cryopreservation of purple-fleshed potato.     

Immune responses to highly conserved influenza A virus matrix 1 peptides

Influenza vaccine development is considered to be complicated and challenging. Constantly evolving influenza viruses require continuous global monitoring and reformulation of the vaccine strains. Peptides that are conserved among different strains and subtypes of influenza A virus are strongly considered to be attractive targets for development of cross protective influenza vaccines that stimulate cellular responses. In this study, three highly conserved (>90%) matrix 1 peptides that contain multiple T cell epitopes, ILGFVFTLTVPSERGLQRRRF (P_M1), LIRHENRMVLASTTAKA (P_M2) and LQAYQKRMGVQMQR (P_M3), were assessed for their immunogenic potential in vitro by subjecting peripheral blood mononuclear cells from healthy volunteers to repetitive stimulation with these chemically synthesised peptides and measuring their IFN‐γ concentrations, proliferation by ELISA, and 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide assay, respectively. Seven samples were screened for immunogenicity of P_M1 and P_M2, and six for that of P_M3. All six samples had positive responses (IFN‐γ secretion) to P_M3 stimulation, as did five and three for P_M2 and P_M1 respectively. In contrast, seven (P_M1 and P_M2) and four (P_M3) samples showed proliferative response as compared with unstimulated cells. The encouraging immunogenic response generated by these highly conserved matrix 1 peptides indicates they are prospective candidates for development of broadly reactive influenza vaccines.