miR-30a attenuates drug sensitivity to 5-FU by modulating cell proliferation possibly by downregulating cyclin E2 in oral squamous cell carcinoma

We aimed to determine the functional role of the miRNA, which affects drug sensitivity to 5-FU in oral squamous cell carcinoma (OSCC), using two types of 5-FU-resistant and parental OSCC cell lines. MiRNA microarray data showed that miR-30a was significantly upregulated in two resistant cell lines. Therefore, we investigated the effects and molecular mechanism of miR-30a on 5-FU sensitivity. Stable overexpression of miR-30a in parental OSCC cells decreased cell proliferation and attenuated drug sensitivity to 5-FU. Cell cycle analysis indicated that miR-30a overexpression increased the proportion of G1 phase cells and decreased the proportion of S phase cells. MiR-30a knockdown using siRNA reversed the effects of miR-30a overexpression. DNA microarray analysis using miR-30a-overexpressing cell lines and a TargetScan database search showed that cyclin E2 (CCNE2) is a target of miR-30a. A luciferase reporter assay confirmed that a miR-30a mimic interacted with the specific binding site in the 3' UTR of CCNE2. CCNE2 knockdown with siRNA in OSCC cells yielded decreased drug sensitivity to 5-FU, similar to miR-30a overexpressing cells. These findings suggest that miR-30a in OSCC may be a novel biomarker of 5-FU-resistant tumors, as well as a therapeutic target for combating resistance.     

TGF-β1 increases cellular invasion of colorectal neuroendocrine carcinoma cell line through partial epithelial-mesenchymal transition

Epithelial–mesenchymal transition (EMT) plays a pivotal role in cancer progression and metastasis in many types of malignancies, including colorectal cancer. Although the importance of EMT is also considered in colorectal neuroendocrine carcinoma (NEC), its regulatory mechanisms have not been elucidated. We recently established a human colorectal NEC cell line, SS-2. In this study, we aimed to clarify whether these cells were sensitive to transforming growth factor beta 1 (TGF-β1) and whether EMT could be induced through TGF-β1/Smad signaling, with the corresponding NEC cell-specific changes in invasiveness. In SS-2 cells, activation of TGF-β1 signaling, as indicated by phosphorylation of Smad2/3, was dose-dependent, demonstrating that SS-2 cells were responsive to TGF-β1. Analysis of EMT markers showed that mRNA levels changed with TGF-β1 treatment and that E-cadherin, an EMT marker, was expressed in cell-cell junctions even after TGF-β1 treatment. Invasion assays showed that TGF-β1-treated SS-2 cells invaded more rapidly than non-treated cells, and these cells demonstrated increased metalloproteinase activity and cell adhesion. Among integrins involved in cell-to-matrix adhesion, α2-integrin was exclusively upregulated in TGF-β1-treated SS-2 cells, but not in other colon cancer cell lines, and adhesion and invasion were inhibited by an anti-α2-integrin blocking antibody. Our findings suggest that α2-integrin may represent a novel therapeutic target for the metastasis of colorectal NEC cells.     

Sperm storage in male elasmobranchs: A description and survey

Two basic types of spermatozoan aggregates, spermatophores and spermatozeugmata, found in 14 different species of sharks, one species of skate, and one species of chimaera (holocephalan), were investigated using light and scanning electron microscopy. Spermatophores, aggregates (usually 1,000–6,000 μm in diameter and larger) of randomly clumped sperm embedded in and surrounded by an eosinophilic matrix, were found in Alopias superciliosus, Odontaspis taurus, Carcharodon carcharias, Isurus oxyrinchus, and Lamna nasus. Three types of spermatozeugmata, sperm structures without a surrounding capsule or matrix, are described. The first, clumps of 60–200 sperm unbound in a supporting matrix, are found in Squalus acanthias and Hydrolagus colliei. In the second type, single-layered spheres are formed of sperm clumps with the sperm heads bound in a common supporting matrix. These are found in Carcharhinus limbatus and Carcharhinus plumbeus. The third type of spermatozeugmata are large multilayered, compound structures formed by the accretion of several single-layered aggregates. These multilayered structures characteristically are found in Carcharhinus falciformis, C. limbatus, Carcharhinus obscurus, C. plumbeus, Carcharhinus porosus, Prionace gluaca, Rhizoprionodon terraenovae, and Sphyrna lewini. Sperm aggregates of all types are stored between the septa and in the lumen of the terminal ampulla of the epididymis. In their various forms they are the final product of the mature male elasmobranch reproductive tract. In a male with mature claspers, the presence of sperm aggregates is a more reliable indicator of maturity and sexual activity than is clasper condition alone. © 1994 Wiley-Liss, Inc.     

Biosynthetic gene cluster identification and biological activity of lucilactaene from Fusarium sp. RK97-94

ABSTRACT

We identified the biosynthetic gene cluster for lucilactaene, a cell cycle inhibitor from a filamentous fungus Fusarium sp. RK 97–94. The luc1 knockout strain accumulated demethylated analogs, indicating the involvement of Luc1 methyltransferase in lucilactaene biosynthesis. Lucilactaene showed potent antimalarial activity. Our data suggested that methylation and ether ring formation are essential for its potent antimalarial activity.     

Brazilian red propolis extract enhances expression of antioxidant enzyme genes in vitro and in vivo

ABSTRACT

Brazilian red propolis reportedly has reactive oxygen species (ROS) scavenging effects in vitro, but the cellular mechanisms remain unclear. In the present study, the effects of an ethanol extract of Brazilian red propolis (EERP) on the Nrf2-ARE intracellular antioxidant pathway were examined in vitro and in vivo. EERP and its constituents transactivated the reporter gene through the ARE sequence and enhanced the expression of Nrf2-regulated genes in HEK293 cells. It also increased Nrf2 protein in the nucleus, which was partially inhibited by kinase inhibitors. Furthermore, EERP suppressed ROS generation and cytotoxicity induced by tert-butyl hydroperoxide. In vivo, orally administered EERP increased the expression of Nrf2-regulated genes in mice liver. These results suggest that EERP is a potential resource for preventing oxidative stress-related diseases as an Nrf2 inducer.