The shape and size distribution of crystalline nanoparticles prepared by acid hydrolysis of native cellulose

The shape and size distribution of crystalline nanoparticles resulting from the sulfuric acid hydrolysis of cellulose from cotton, Avicel, and tunicate were investigated using transmission electron microscopy (TEM) and atomic force microscopy (AFM) as well as small- and wide-angle X-ray scattering (SAXS and WAXS). Images of negatively stained and cryo-TEM specimens showed that the majority of cellulose particles were flat objects constituted by elementary crystallites whose lateral adhesion was resistant against hydrolysis and sonication treatments. Moreover, tunicin whiskers were described as twisted ribbons with an estimated pitch of 2.4-3.2 microm. Length and width distributions of all samples were generally well described by log-normal functions, with the exception of tunicin, which had less lateral aggregation. AFM observation confirmed that the thickness of the nanocrystals was almost constant for a given origin and corresponded to the crystallite size measured from peak broadening in WAXS spectra. Experimental SAXS profiles were numerically simulated, combining the dimensions and size distribution functions determined by the various techniques.     

miR-483-3p suppresses the proliferation and progression of human triple negative breast cancer cells by targeting the HDAC8>oncogene

Triple negative breast cancer (TNBC) is a heterogeneous subclass of breast cancer (BC) distinguished by lack of hormone receptor expression. It is highly aggressive and difficult to treat with traditional chemotherapeutic regimens. Targeted-therapy using microRNAs (miR) has recently been proposed to improve the treatment of TNBC in the early stages. Here, we explore the roles of miR-483-3p/HDAC8 HDAC8 premiR-vector on tumorigenicity in TNBC patients. Clinical TNBC specimens and three BC cell lines were prepared. miR-483-3p and expression levels were measured using quantitative real-time polymerase chain reaction. Cell cycle progression was assessed by a flow-cytometry method. We also investigated cell proliferation by 3-2, 5-diphenyl tetrazolium bromide assay and colony formation assay. We used a to overexpress miR-483-3p, and a HDAC8-KO-vector for knocking out the endogenous production of HDAC8. Our data showed significant downregulation of miR-483-3p expression in TNBC clinical and cell line samples. The HDAC8 was also upregulated in both tissue specimens and BC cell lines. We found that increased levels of endogenous miR-483-3p affects tumorigenecity of MDA-MB-231. Downregulation of HDAC8 using the KO-vector showed the same pattern. Our results revealed that the miR-483-3p suppresses cellular proliferation and progression in TNBC cell lines via targeting HDAC8. Overall, our outcomes demonstrated the role of miR-483-3p as a tumor suppressor in TNBC and showed the possible mechanism via HDAC8. In addition, targeted treatment of TNBC with miR-483-3p might be considered in the future.     

Global microRNA expression profiling identifies MiR-210 associated with tumor proliferation, invasion and poor clinical outcome in breast cancer

Purpose

Aberrant microRNA (miRNA) expression is associated with cancer and has potential diagnostic and prognostic value in various malignancies. In this study, we investigated miRNA profiling as a complementary tool to improve our understanding of breast cancer (BC) biology and to assess whether miRNA expression could predict clinical outcome of BC patients.

Experimental Design

Global miRNA expression profiling using microarray technology was conducted in 56 systemically untreated BC patients who had corresponding mRNA expression profiles available. Results were further confirmed using qRT-PCR in an independent dataset of 89 ER-positive BC patients homogeneously treated with tamoxifen only. MiR-210 functional analyses were performed in MCF7 and MDA-MB-231 BC cell lines using lentiviral transduction.

Results

Estrogen receptor (ER) status, tumor grade and our previously developed gene expression grade index (GGI) were associated with distinct miRNA profiles. Several miRNAs were found to be clinically relevant, including miR-210, its expression being associated with tumor proliferation and differentiation. Furthermore, miR-210 was associated with poor clinical outcome in ER-positive, tamoxifen-treated BC patients. Interestingly, the prognostic performance of miR-210 was similar to several reported multi-gene signatures, highlighting its important role in BC differentiation and tumor progression. Functional analyses in BC cell lines revealed that miR-210 is involved in cell proliferation, migration and invasion.

Conclusions

This integrated analysis combining miRNA and mRNA expression demonstrates that miRNA expression provides additional biological information beyond mRNA expression. Expression of miR-210 is linked to tumor proliferation and appears to be a strong potential biomarker of clinical outcome in BC.     

The acid tolerant and cold-active β-galactosidase from Lactococcus lactis strain is an attractive biocatalyst for lactose hydrolysis

The gene encoding the β-galactosidase from the dairy Lactococcus lactis IL1403 strain was cloned, sequenced and overexpressed in Escherichia coli. The purified enzyme has a tetrameric arrangement composed of four identical 120 kDa subunits. Biochemical characterization showed that it is optimally active within a wide range of temperatures from 15 to 55 °C and of pH from 6.0 to 7.5. For its maximal activity this enzyme requires only 0.8 mM Fe²⁺ and 1.6 mM Mg²⁺. Purified protein displayed a high catalytic efficiency of 102 s^?1 mM^?1 for lactose. The enzyme stability was increased by immobilization mainly at low pH (from 4.0 to 5.5) and high temperatures (55 and 60 °C). The bioconversion of lactose using the L. lactis β-galactosidase allows the production of lactose with a high bioconversion rate (98 %) within a wide range of pH and temperature.     

MNK1 expression increases during cellular senescence and modulates the subcellular localization of hnRNP A1

Heterogeneous nuclear ribonucleoprotein A1 (hnRNP A1) is an RNA-binding protein that modulates splice site usage, polyadenylation, and cleavage efficiency. This protein has also been implicated in mRNA stability and transport from the nucleus. We have previously demonstrated that hnRNP A1 had diminished protein levels and showed cytoplasmic accumulation in senescent human diploid fibroblasts. Furthermore, we have shown that inhibition of p38 MAPK, a key regulator of cellular senescence, elevated hnRNP A1 protein levels and inhibited hnRNP A1 cytoplasmic localization. In this study, we have explored the possible involvement of MNK1, one of the downstream effector of p38 MAPK, in the regulation of hnRNP A1. We have demonstrated that pharmacological inhibition of MNK1 by CGP 57380 decreased the phosphorylation levels of hnRNP A1 in young and senescent fibroblast cells and blocked the cytoplasmic accumulation of hnRNP A1 in senescent cells. In addition, MNK1 formed a complex with hnRNP A1 in vivo. The expression levels of MNK1, phospho-MNK1, and phospho-eIF4E proteins were found to be elevated in senescent cells. These data suggest that MNK1 regulates the phosphorylation and the subcellular distribution of hnRNP A1 and that MNK1 may play a role in the induction of senescence.