Sirtuin1 (SIRT1) is a nicotinamide adenine dinucleotide-dependent deacetylase. Recently, it is suggested that SIRT1 may be involved in the development of malignant tumors including mouse lymphoma. Therefore, we investigated the prevalence and the prognostic impact of SIRT1 expression in diffuse large B-cell lymphoma (DLBCL). Immunohistochemical expression of SIRT1, p53, bcl2, CD10, bcl6, and multiple myeloma-1 (MUM1) were evaluated by using a 2 mm core from 104 DLBCL patients for tissue microarray. Positive expression of SIRT1 was seen in 74% (77/104) of patients. In total DLBCL patients, SIRT1 and p53 expression were significantly associated with shorter overall survival (OS) by univariate analysis (P=0.001 and P=0.011, respectively). SIRT1 was also an independent prognostic factor by multivariate analysis (P=0.01). According to the expression patterns of CD10, bcl6, and MUM1, germinal center B cell (GCB) types were represented in 38 cases (37%) and non-GCB types were represented in 66 cases (63%). In the GCB type, only p53 expression was associated with a significantly shorter OS (P=0.032). In the non-GCB type, expression of SIRT1 correlated with shorter OS by univariate analyses (P=0.005) and multivariate analyses (P=0.049). In conclusion, we showed that SIRT1 expression is a clinically significant prognostic indicator for DLBCL patients.

Effects of the degree of deacetylation (DDA) and the molecular mass of chitosan oligosaccharides (CTS-OS), obtained from the enzymatic hydrolysis of high molecular weight chitosan (HMWC), on antitumor activity was explored. The DDA and molecular weights of CTS-OS were determined by matrix-assisted laser desorption/ionization-mass spectrometry (MALDI-TOF MS) analysis. The CTS-OS were found to be a mixture of mainly dimers (18.8%), trimers (24.8%), tetramers (24.9%), pentamers (17.7%), hexamers (7.1%), heptamers (3.3%), and octamers (3.4%). The CTS-OS were further fractionated by gel-filtration chromatography into two major fractions: (1) COS, consisting of glucosamine (GlcN)n, n = 3–5 with DDA 100%; and (2) HOS, consisting of (GlcN)5 as the minimum residues and varying number of N-acetylglucosamine (GlcNAc)n, n = 1–2 with DDA about 87.5% in random order. The cytotoxicities, expressed as the concentration needed for 50% cell death (CC50), of CTS-OS, COS, and HOS against PC3 (prostate cancer cell), A549 (lung cancer cell), and HepG2 (hepatoma cell), were determined to be 25 μg·mL−1, 25 μg·mL−1, and 50 μg·mL−1, respectively. The HMWC was approximately 50% less effective than both CTS-OS and COS. These results demonstrate that the molecular weight and DDA of chitosan oligosaccharides are important factors for suppressing cancer cell growth.

Abstract. The discoidin domain receptor (DDR) is a class of receptor tyrosine kinases that binds to several collagens. DDR1 is widely expressed in fast-growing invasive tumors of the breast, ovary, esophagus, brain and lung. However, there is little information on the expression of DDR1 in hepatocellular carcinoma (HCC) or its function in migration and invasion. Western blot analysis was performed to determine if four HCC cell lines (HLE, Huh-7, HepG2 and SH-J1) express DDR1. The HLE and Huh-7 cell lines were transfected with two isoforms of DDR1, DDR1a and DDR1b. Immunoprecipitation for DDR1 was then performed. Migration and invasion assays were carried out and the number of migrating cells was counted in 6 randomly selected fields per well under an optical microscope. Zymography was used to determine the level of the matrix metalloproteinase (MMP)-2 and -9 expression. DDR1 was expressed in all four cell lines. In the migration assay, the number of migrating cells was significantly higher in the DDR1a-or DDR1b-overexpressing HLE and Huh-7 cells, particularly after collagen type I stimulation (P<0.001). Collagen type I stimulation activated DDR1. In the invasion assay, there was a significantly higher number of invading cells in the DDR1a-or DDR1b-overexpressing HLE cells and DDR1a-overexpressing Huh-7 cells than in the control (P<0.01). The DDR1a-and DDR1b-overexpressing HLE cells showed a remarkable increase in the MMP-9 and -2 expression, particularly the active MMP-2. The DDR1a-and DDR1b-overexpressing Huh-7 cells showed a slight increase in the MMP-9 and -2 expression. The increased invasiveness of the HCC may be associated with the overexpression of either DDR1a or DDR1b mediated by MMP-2 and -9. Although this study provided one possible mechanism for the invasion of HCC cells, more studies are needed to understand the signal through which DDR1a and DDR1b act in invasion.

Tumor-infiltrating immune cells perform a crucial function in host immune reactions against diffuse large B-cell lymphoma (DLBCL). In this study, we have identified a subset of tumor-infiltrating FOXP3-positive regulatory T cells (Tregs) in the initial DLBCL biopsy specimens, and have evaluated their prognostic significance. Ninety six patients with DLBCL were evaluated retrospectively. The pattern of FOXP3 protein expression was evaluated using standard immunohistochemistry in paraffin-embedded tissue samples. Sixty seven of all 96 specimens were stained with antibodies for CD-10, bcl-6 and MUM1 via tissue microarray (TMA) to classify the cases into a germinal center B-cell like (GCB) group and a non-GCB group. The median overall survival (OS) was 28 months. As compared with the others, the patients with higher percentages of FOXP3-positive Tregs on initial tumor biopsy evidenced a significantly longer OS (p = 0.003). Patients classified into the GCB group evidenced a significantly longer OS as compared with the non-GCB group (p = 0.008). When the prognostic factors were evaluated via a multivariate model, the international prognostic index and the percentage of infiltrating FOXP3-positive Tregs in the initial biopsy were identified as independent predictors of OS. In conclusion, the presence of an increased percentage of FOXP3-positive Tregs in DLBCL is predictive of better prognoses.

The acquisition of a migratory and invasive phenotype by cells of epithelial origin is associated with a gain of mesenchymal characteristics concomitant with a loss of the epithelial phenotype, a phenomenon referred to as epithelial-mesenchymal transition (EMT). Vimentin, a cytoplasmic intermediate filament, is characteristic of mesenchymal cells and is usually not expressed in epithelial cells. Increased expression of vimentin in carcinomas correlates with parameters of malignant potential such as tumor grade and tumor invasion. Serum response factor (SRF) regulates transcription of immediate early genes and triggers proliferation, migration and differentiation in several types of cells. However, the role of SRF in hepatocellular carcinoma (HCC) has not been explored. The aims of this study were to evaluate the expression of SRF and to assess a functional role of SRF in HCC. First, we examined the expression of SRF in 55 human specimens of HCC and four different HCC cell lines, including a sarcomatoid HCC cell line. We also examined the role of SRF in HCC by transfection of an SRF expression plasmid into a HCC cell line. SRF was expressed in 13 of 55 cases of HCC. SRF was predominantly expressed in HCC cells, with intense labeling in the nucleus. No staining was observed in hepatocytes of normal and cirrhotic liver outside the tumor. SRF was significantly up-regulated in high grade HCC, especially in sarcomatoid HCC. Overexpression of SRF in hepatocellular carcinoma cells accelerates migration and invasion with subsequent acquisition of mesenchymal phenotype by expression of a mesenchymal marker (vimentin) and activation of immediate early genes. We propose for the first time that the expression of SRF in HCC cells associated with EMT may play an important role in HCC progression. Thus, functional antagonism of SRF will provide an additional therapeutic approach by controlling tumor cell invasion and metastasis.