Hideaki Shimada

Identification of Altered Protein Expression and Post-Translational Modifications in Primary Colorectal Cancer by Using Agarose Two-Dimensional Gel Electrophoresis

Purpose: Although numerous proteome studies have been performed recently to identify cancer-related changes in protein expression, only a limited display of relatively abundant proteins has been identified. The aim of this study is to identify novel proteins as potential tumor markers in primary colorectal cancer tissues using a high-resolution two-dimensional gel electrophoresis (2-DE). Experimental Design: 2-DE using an agarose gel for isoelectric focusing was used to compare protein profiling of 10 colorectal cancer tissues and adjacent normal mucosa. Altered expression and post-translational modification of several proteins were examined using Western blot analysis and immunohistochemistry. Results: Ninety-seven proteins of 107 spots (90.7%) that were differentially expressed between matched normal and tumor tissues were identified by mass spectrometry. Among them, 42 unique proteins (49 spots) significantly increased or decreased in the tumors. They include eukaryotic translation initiation factor 4H, inorganic pyrophosphatase, anterior gradient 2 homologue, aldolase A, and chloride intracellular channel 1, whose elevated expression in tumor tissues was confirmed by Western blot analysis and immunohistochemistry. Interestingly, only isoform 1 of two transcript variants of eukaryotic translation initiation factor 4H was greatly up-regulated in most of the tumor tissues. Moreover, post-translational modifications of the prolyl-4-hydroxylase β subunit and annexin A2 also were identified. Conclusions: We identified several novel proteins with altered expression in primary colorectal cancer using agarose 2-DE. This method is a powerful technique with which to search for not only quantitative but also qualitative changes in a biological process of interest and may contribute to the deeper understanding of underlying mechanisms of human cancer.

EFFECTS OF COMBINATION TREATMENT WITH FK506 AND CYCLOSPORINE ON SURVIVAL TIME AND VASCULAR CHANGES IN RENAL-ALLOGRAFT-RECIPIENT DOGS

In our previous experiments studying the effects of FK506 on renal allografting in the dog, we encountered two major problems. One problem was anorexia and the other problem was vascular changes mainly in the recipient heart. Anorexia was generally dose dependent, but the vascular changes were seen to be more prominent at lower doses rather than at higher immunosuppressive doses. The present study was undertaken to study these two problems. A nonanorexic, vascular change-related, nonimmunosuppressive dose of FK506 was combined with a low dose of cyclosporine or prednisolone in beagle dogs after renal allografting. Treatment with either FK506 alone at a dose of 0.32 mg/kg or cyclosporine alone at 2.5 mg/kg was not effective in prolonging renal recipient survival. The recipient dogs died of rejection, and a variety of vascular changes were observed in the hearts of both groups. Combined treatment with FK506 and cyclosporine at these same doses resulted in statistically significant prolongation of the survival time of the renal recipient (P less than 0.01), and histologic studies showed that the frequency and severity of the vascular changes were suppressed in the recipient receiving the combined treatment. The combination of FK506 and prednisolone at 0.5 mg/kg was not effective in prolonging survival. Furthermore, the extent of vascular changes was similar to those found in recipients receiving FK506 alone. The data suggest that combined treatment with low doses of both FK506 and cyclosporine acted synergistically in prolonging canine renal allografts and that the vascular changes frequently seen at low doses of FK506 were reduced by additional immunosuppression with a low dose of cyclosporine.

Inhibition of subgenomic hepatitis C virus RNA in Huh-7 cells: ribavirin induces mutagenesis in HCV RNA.

Summary.  Hepatitis C virus (HCV) infection is a major problem throughout the world. Combination therapy of interferon (IFN) and ribavirin is the best treatment for eradication at present, but the mechanism is not completely understood. We used the HCV replicon system to investigate this mechanism. The effects of six drugs (UDCA, glycyrrhizin, TJ‐9, bezafibrate, ribavirin, and alpha‐IFN 2b) on HCV subgenomic RNA (genotype 1b, NS5B 415Y) were examined by reverse transcription polymerase chain reaction, cloning and sequencing. The HCV replication was inhibited by alpha‐IFN 2b (7.39–13.2% at 10 U/mL, 3.29–6.12% at 100 U/mL, 1.3–4.86% at 1000 U/mL) and by ribavirin (4.36–13.9% at 100 μg/mL), but not by the other drugs at 24–72 h after treatment. Furthermore, the combination treatment was superior to IFN monotherapy and to ribavirin monotherapy at 72 h post‐treatment. Sequence analyses of the double‐stranded RNA‐activated protein kinase (PKR)‐binding domain and flanking regions within the HCV NS5A region revealed that the total numbers of substitutions caused by ribavirin (n = 36) or combination treatment (n = 57) were more than those of IFN alone (n = 5) and controls (n = 6). The HCV replicon system is the most efficient system for HCV replication and is an excellent choice for testing anti‐HCV drugs and disinfectants. Our results further suggested that the combination of alpha‐IFN 2b and ribavirin might induce mutations, and inhibit HCV RNA synthesis in hepatocytes to a greater extent than ribavirin monotherapy.

c-myc suppressor FBP-interacting repressor for cancer diagnosis and therapy

Based on the genetic background of cancer, we have been trying to develop novel diagnostic and therapeutic strategies against human cancers. c-myc gene activation has been detected in many human cancers, indicating a key role of c-myc in tumor development. Thus targeting c-myc gene suppression is a promising strategy for cancer treatment. Recently, an interaction between FIR (FUSE-Binding Protein-Interacting Repressor) and TFIIH/p89/XPB helicase was found to repress c-myc transcription and so might be important for suppressing tumor formation. Previously, we have shown that the expression of splicing variant of FIR is elevated in colorectal cancer tissues and promotes tumor development by disabling FIR-repression to sustain high levels of c-Myc, opposing apoptosis in cancer cells. In this study, FIR recombinant adenovirus vector induces tumor growth suppression against tumor xenografts in animal model experiment. Together, one clue to the development of cancer diagnosis and therapies directed against c-Myc may go through FIR and its splicing variant.

Adenovirus-mediated FIR demonstrated TP53-independent cell-killing effect and enhanced antitumor activity of carbon-ion beams

Combination therapy of carbon-ion beam with the far upstream element-binding protein (FBP)-interacting repressor, FIR, which interferes with DNA damage repair proteins, was proposed as an approach for esophageal cancer treatment with low side effects regardless of TP53 status. In vivo therapeutic antitumor efficacy of replication-defective adenovirus (E1 and E3 deleted adenovirus serotype 5) encoding human FIR cDNA (Ad-FIR) was demonstrated in the tumor xenograft model of human esophageal squamous cancer cells, TE-2. Bleomycin (BLM) is an anticancer agent that introduces DNA breaks. The authors reported that Ad-FIR involved in the BLM-induced DNA damage repair response and thus applicable for other DNA damaging agents. To examine the effect of Ad-FIR on DNA damage repair, BLM, X-ray and carbon-ion irradiation were used as DNA damaging agents. The biological effects of high linear energy transfer (LET) radiotherapy used with carbon-ion irradiation are more expansive than low-LET conventional radiotherapy, such as X-rays or γ rays. High LET radiotherapy is suitable for the local control of tumors because of its high relative biological effectiveness. Ad-FIR enhanced BLM-induced DNA damage indicated by γH2AX in vitro. BLM treatment increased endogenous nuclear FIR expression in TE-2 cells, and P27Kip1 expression was suppressed by TP53 siRNA and BLM treatment. Further, Ad-FIRΔexon2, a dominant-negative form of FIR that lacks exon2 transcriptional repression domain, decreased Ku86 expression. The combination of Ad-FIR and BLM in TP53 siRNA increased DNA damage. Additionally, Ad-FIR showed synergistic cell toxicity with X-ray in vitro and significantly increased the antitumor efficacy of carbon-ion irradiation in the xenograft mouse model of TE-2 cells (P=0.03, Mann–Whitney’s U-test) and was synergistic with the sensitization enhancement ratio (SER) value of 1.15. Therefore, Ad-FIR increased the cell-killing activity of the carbon-ion beam that avoids late-phase severe adverse effects independently of the TP53 status in vitro. Our findings indicated the feasibility of the combination of Ad-FIR with DNA damaging agents for future esophageal cancer treatment.

Serum SH3BP5-specific Antibody Level is a Biomarker of Atherosclerosis

Abstract Background: The discovery and development of novel biomarkers that could facilitate early diagnosis and thus prevent the progression of atherosclerosis-related diabetes mellitus (DM), cerebral infarction (CI), and cardiovascular disease (CVD) has garnered much research interest. Notably, recent reports have described a number of highly sensitive antibody markers. In this study, we aimed to identify additional antibody markers that would facilitate screening. Methods: The amplified luminescent proximity homogeneous assay (AlphaLISA) method, which incorporates glutathione- or streptavidin-donor beads and anti-human-IgG-acceptor beads, was used to evaluate serum antibody levels in serum samples. The protein array method was used for the initial screening, and peptide arrays were used to identify epitope sites. Results: The protein array identified SH3 domain-binding protein 5 (SH3BP5) as a target antigen of serum IgG antibodies in the sera of patients with atherosclerosis. We prepared recombinant glutathione S-transferase (GST)- fused SH3BP5 protein. Peptide arrays revealed that the epitope site recognized by serum antibodies is located within amino acids 161–174 of SH3BP5. AlphaLISA revealed significantly higher serum antibody levels against both the SH3BP5 protein and peptide in patients with DM, acute-phase CI, transient ischemic attack, CVD or chronic kidney disease (CKD), than in healthy donors. Furthermore, areas under the receiver operating characteristic curves of these antibodies were higher in patients with CKD and DM than in other patients. Spearman correlation analysis revealed associations between the serum antibody levels against SH3BP5 peptide and artery stenosis, hypertension, and smoking. Conclusions: The serum anti-SH3BP5 antibody marker appears to be useful for estimating the progress of atherosclerosis and may discriminate atherosclerosis associated with hypertension and/or habitual smoking.