Role of α5β1 and αvβ3 integrins in relation to adhesion and spreading dynamics of prostate cancer cells interacting with fibronectin under in vitro conditions

Interaction of cell integrins with the ECM (extracellular matrix) proteins is commonly assumed to be associated with cell dissemination and tumour metastases. Since these processes depend on the mechanism of cell-protein interaction, we have attempted to show the contribution of α5β1 and αvβ3 integrins of the prostate cancer PC-3 cells in in vitro interaction with FN (fibronectin) adsorbed on defined polystyrene surfaces. Cell adhesion, spreading and cytoskeleton organization were studied using antibodies against integrins or a GRGDSP (Gly-Arg-Gly-Asp-Ser-Pro) peptide. The results show that blocking the α5β1 integrin causes: (i) a decrease in the number of the adherent cells in the early phase of adhesion and (ii) a decrease in the dynamics of cell spreading and cell shape changes, and weaker reorganization of cytoskeletal proteins than in the control cells. Conversely, the blocking of the αvβ3 integrin: (i) causes no observable effect on the number of the adhered cells; however, (ii) causes an increase in the dynamics of cell spreading and cell shape changes, and stronger reorganization of cytoskeletal proteins than in the control cells. Interestingly, the blocking of integrins with a GRGDSP peptide strongly decreases the number of the adhered cells, and a complete inhibition of cell spreading. Our results strongly suggest that the α5β1 integrin plays the main role in the adhesion and spreading of PC-3 cells interacting with FN, whereas the αvβ3 integrin seems to regulate other receptors in the spreading process. Moreover, integrin-FN interaction through the RGD sequence evidently curbed the cell adhesion and spreading.     

Synthesis of novel β-carboline based chalcones with high cytotoxic activity against breast cancer cells

A series of novel β-carboline based chalcones was synthesized and evaluated for their cytotoxic activity against a panel of human cancer cell lines. Among them we found that two of the compounds 7c and 7d, showed marked anti-proliferative activity in a panel of solid tumor cell lines with highest effect in breast cancer. The compounds 7c and 7d showed an IC₅₀ of 2.25 and 3.29 μM, respectively against human breast cancer MCF-7 cell line. Further, the compound 7c markedly induced DNA fragmentation and apoptosis in breast cancer cells.     

Enhancement of mycobactericidal activity of glutaraldehyde with α,β-unsaturated and aromatic aldehydes

Summary Several ,-unsaturated and aromatic aldehydes were evaluated for antimicrobial activity usingMycobacterium bovis as the test strain. Activity of most of the compounds was determined in the presence and absence of 2% glutaraldehyde. Several compounds highly active against this organism, e.g. 2-pentenal, benzaldehyde, ando-phthalaldehyde showed rapid kill of >10⁵ CFU ml^–1 in 5 min. Activity of ,-unsaturated compounds substituted in the ₁ position showed increasing activity with increasing chain length. Of the aromatic aldehydes tested, benzaldehyde andp-dimethylamino benzaldehyde showed little activity alone, but when combined with 2% glutaraldehyde showed increased activity. Substituents added to the benzaldehyde ring (nitro, chloro, methyl, and methoxy) all detracted from the synergism, but still showed increased activity over the activity of 2% glutaraldehyde. The same affect was noted with disubstituted benzaldehyde compounds but not with substitutedo-phthaladehyde (2-formylformaldehyde).     

The mechanism for thermal-enhanced chaperone-like activity of α-crystallin against UV irradiation-induced aggregation of γD-crystallin

Exposure to solar UV irradiation damages γ-crystallin, leading to cataract formation via aggregation. α-Crystallin, as a small heat shock protein, efficiently suppresses this irreversible aggregation by selectively binding the denatured γ-crystallin monomer. In this study, liquid chromatography tandem mass spectrometry was used to evaluate UV-325 nm irradiation-induced photodamage of human γD-crystallin in the presence of bovine α-crystallin, atomic force microscope (AFM) and dynamic light scattering (DLS) techniques were used to detect the quaternary structure changes of the α-crystallin oligomer, and Fourier transform infrared spectroscopy and temperature-jump nanosecond time-resolved IR absorbance difference spectroscopy were used to probe the secondary structure changes of bovine α-crystallin. We find that the thermal-induced subunit dissociation of the α-crystallin oligomer involves the breaking of hydrogen bonds at the dimeric interface, leading to three different spectral components at varied temperature regions as resolved from temperature-dependent IR spectra. Under UV-325 nm irradiation, unfolded γD-crystallin binds to the dissociated α-crystallin subunit to form an αγ-complex, then follows the reassociation of the αγ-complex to the partially dissociated α-crystallin oligomer. This prevents the aggregation of denatured γD-crystallin. The formation of the γD-bound α-crystallin oligomer is further confirmed by AFM and DLS analysis, which reveals an obvious size expansion in the reassociated αγ-oligomers. In addition, UV-325 nm irradiation causes a peptide bond cleavage of γD-crystallin at Ala158 in the presence of α-crystallin. Our results suggest a very effective protection mechanism for subunits dissociated from α-crystallin oligomers against UV irradiation-induced aggregation of γD-crystallin, at the expense of a loss of a short C-terminal peptide in γD-crystallin.     

Reactivity of δ-substituted α,β-unsaturated cyclic lactones with antileishmanial activity

The present study examines a set of 43 compounds for their antileishmanial activities and cytotoxicities. Negative lowest unoccupied molecular orbitas and similar values for the electrophilic Fukui function condensed at the β-position for a subset of δ-substituted α,β-unsaturated cyclic lactones classify them as strong Michael acceptors. There was a well-defined trend of increasing antileishmanial activity with increasing cytotoxicity and large selectivity indices for the most active compounds. Softer compounds were more active than harder ones as observed from the experimental data and rationalised by calculated reactivity indices.     

Increased chaperone activity of human α‌B-crystallin with incomplete oxidation as a new defense mechanism against oxidative stress

Previous research has shown that production of the high levels of oxidants overwhelms the body's antioxidant defense system during diabetes mellitus. Under this circumstance, ocular lens proteins are one of the main molecular targets for oxidative damage. In the present study, the individual effect of partial and extensive oxidation on the structure and function of human αB-crystallin was investigated using electrophoresis and various spectroscopic methods. The results of our study suggested that widespread oxidation causes loss of the chaperone activity of this protein, while partial oxidation significantly enhances this activity. Our studies also suggested that partial and extensive oxidation induces the formation of different structures in this protein. In fact, the chaperone-active and chaperone-inactive states of this protein are respectively associated with a minor and extensive structural alteration. Moreover, the oligomeric size distribution shows an inverse relationship with the chaperone activity of this protein. Increasing the chaperone activity of this protein during partial oxidation may be a natural defense mechanism to overcome the damages caused by oxidative stress, especially in diabetes and other pathological diseases.     

The microbiological activity of α-keto-β,β-dimethyl-γ-butyrolactone

α-Keto-β,β-dimethyl-γ-butyrolactone is as active as pantoic acid in promoting growth of E. coli M-99-3, and is approximately three times as active as pantoic acid in promoting growth of E. coli M-99-4 and in reversing salicylate inhibition of E. coli; it is inactive in promoting growth of E. coli M-99-1 and only about 3% as effective as pantoic acid in promoting the growth of Acetobacter suboxydans.     

Synthesis,cytotoxicity against human oral cancer KB cells and structure–activity relationship studies of trienone analogues of curcuminoids

A general method for the synthesis of substituted (1E,4E,6E)-1,7-diphenylhepta-1,4,6-trien-3-ones, based on the aldol condensations of substituted 4-phenylbut-3-en-2-ones and substituted 3-phenylacrylaldehydes, was achieved. The natural trienones 4 and 5 have been synthesized by this method, together with the trienone analogues 9–20. These analogues were evaluated for their cytotoxic activity against human oral cancer KB cell line. The structure–activity relationship study has indicated that the analogues with the 1,4,6-trien-3-one function are more potent than the curcuminoid-type function. Analogues with meta-oxygen function on the aromatic rings are more potent than those in the ortho- and para-positions. Free phenolic hydroxy group is more potent than the corresponding methyl ether analogues. Among the potent trienones, compounds 11, 18 and 20 were more active than the anticancer drug ellipticine. All compounds were also evaluated against the non-cancerous Vero cells and it was found that compounds 11, 12 and 17 were much less toxic than curcumin (1); they showed high selectivity indices of 35.46, 33.46 and 31.68, respectively. These analogues are regarded as the potent trienones for anti-oral cancer study.     

Localization of α-tubulin immunoreactivity to cerebellar Bergmann glia with the TU 01 antibody

Summary The TU 01 antitubulin antibody specific for -tubulin was demonstrated, by light-and electron-microscopic immunocytochemistry, to stain selectively the Bergmann glia of rat cerebellum. Within the glial cells and their fibres the microtubules, the smooth endoplasmic reticulum, the outer mitochondrial membranes and the ribosomal rosettes of the cell body were decorated by the antibody. The high selectivity of this antibody is discussed in terms of tubulin microheterogeneity.     

Dual regulation effect and mechanism of human myeloid-derived suppressor cells on anticolorectal cancer cells activity of Vγ9Vδ2 T cells

Myeloid-derived suppressor cells (MDSC) are a group of immature inhibitory cells of bone marrow origin. Human γδ T cells (mainly Vγ9Vδ2 T cells) have emerged as dominant candidates for cancer immunotherapy because of their unique recognition pattern and broad killing activity against tumor cells. Intestinal mucosal intraepithelial lymphocytes are almost exclusively γδ T cells, so it plays an important role in inhibiting the development of colorectal cancer. In this study, we investigated the effects and molecular mechanism of human MDSC on anticolorectal cancer cells activity of Vγ9Vδ2 T cells. Our results suggested that MDSC can reduce the NKG2D expression of Vγ9Vδ2 T cells through direct cell–cell contact, which is associated with membrane-type transforming growth factor-β. In contrast, MDSC can increase Vγ9Vδ2 T cells activation and production of IFN-γ, perforin, Granzyme B through direct cell–cell contact. This may be related to the upregulation of T-bet in Vγ9Vδ2 T cells by MDSC. However, MDSC had a dominant negative regulatory effect on the anticolorectal cancer cells activity of Vγ9Vδ2 T cells. Our study provides a theoretical basis for the immune regulatory function of human MDSC on γδ T cells. This will be conducive to the clinical development of a new antitumor therapy strategy.     

Synthesis,characterization and antineoplastic activity of bis-aziridinyl dimeric naphthoquinone – A novel class of compounds with potent activity against acute myeloid leukemia cells

The synthesis, characterization and antileukemic activity of rationally designed amino dimeric naphthoquinone (BiQ) possessing aziridine as alkylating moiety is described. Bis-aziridinyl BiQ decreased proliferation of acute myeloid leukemia (AML) cell lines and primary cells from patients, and exhibited potent (nanomolar) inhibition of colony formation and overall cell survival in AML cells. Effective production of reactive oxygen species (ROS) and double stranded DNA breaks (DSB) induced by bis-aziridinyl BiQ is reported. Bis-dimethylamine BiQ, as the isostere of bis-aziridinyl BiQ but without the alkylating moiety did not show as potent anti-AML activity. Systemic administration of bis-aziridinyl BiQ was well tolerated in NSG mice.     

Characterization of α-amylase inhibitor from rice bean with inhibitory activity against midgut α-amylases from Spodoptera litura

The α-amylase inhibitor (α-AI) activity varied from 7.529 to 10.766 (IU/g) in 13 rice bean with different genotypes. BRS-2 exhibited the highest α-AI activity (55.3%). Rice bean α-AI was purified to homogeneity by 80% ammonium sulfate precipitation, dialysis, ion exchange chromatography on DEAE-Sepharose and gel filtration through Superdex-75. Its homogeneity was confirmed by SDS-PAGE under reducing conditions showing a single band protein of molecular weight 25 kDa. The inhibitor was purified to 75.9 fold with final yield of 28.0% with specific activity of 660.2 IU. Inhibition studies carried out at pH from 2.2 to 9.0 revealed pH optimum at pH 6.9 (69.3%). The maximum α-AI activity was found at 37°C (68.8 %) and the lowest was revealed at 100°C (37.0%). Optimum inhibitory activity was expressed during pre-incubation of enzyme with inhibitor at pH 6.9 and 37°C. Isoelectric focusing of purified inhibitor showed a single band near pH 4.7. The first 6 amino acids in the N-terminus were recorded as Ala-Ser-Ser-Arg-Phe-Cys (ASSRFC). The purified inhibitor inhibited the α-amylase from the larval midgut of Spodoptera litura up to 86.6%. The α-amylase inhibitors are important seed storage proteins because of their potentiality for exploitation in pest control and crop defense against insect infestation. Their expression at high levels can confer resistance in transgenic legumes, which could be exploited for crop improvement.     

Tyrosinated, but not detyrosinated, α-tubulin is present in root tip cells

Summary The distribution of tyrosinated and detyrosinated tubulin in microtubule arrays of pine and onion cells was investigated by immunofluorescence techniques. Staining of isolated cells and methacrylate sections ofPinus radiata andAllium cepa root tips indicated that all microtubule structures contained tyrosinated tubulin but not the posttranslationally modified detyrosinated tubulin. The detyrosinated tubulin epitope was, however, created in vitro by treating both sections and fixed whole cells with carboxypeptidase A.