American Society for Clinical Investigation Acta Medica Okayama 0021-9738 119 10 2009 A simple biological imaging system for detecting viable human circulating tumor cells 3172 3181 EN Toru Kojima Yuuri Hashimoto Yuichi Watanabe Shunsuke Kagawa Futoshi Uno Shinji Kuroda Hiroshi Tazawa Satoru Kyo Hiroyuki Mizuguchi Yasuo Urata Noriaki Tanaka Toshiyoshi Fujiwara The presence of circulating tumor cells (CTCs) in the peripheral blood is associated with short survival, making the detection of CTCs clinically useful as a prognostic factor of disease outcome and/or a surrogate marker of treatment response. Recent technical advances in immunocytometric analysis and quantitative real-time PCR have made it possible to detect a few CTCs in the blood; however, there is no sensitive assay to specifically detect viable CTCs. Here, we report what we believe to be a new approach to visually detect live human CTCs among millions of peripheral blood leukocytes, using a telomerase-specific replication-selective adenovirus expressing GFP. First, we constructed a GFP-expressing attenuated adenovirus, in which the telomerase promoter regulates viral replication (OBP-401; TelomeScan). We then used OBP-401 to establish a simple ex vivo method that was able to detect viable human CTCs in the peripheral blood. The detection method involved a 3-step procedure, including the lysis of rbc, the subsequent addition of OBP-401 to the cell pellets, and an automated scan using fluorescence microscopy. OBP-401 infection increased the signal-to-background ratio as a tumor-specific probe, because the fluorescent signal was amplified only in viable, infected human tumor cells, by viral replication. This GFP-expressing virus-based method is remarkably simple and allows precise enumeration of CTCs. No potential conflict of interest relevant to this article was reported.

The American Society for Biochemistry and Molecular Biology, Inc. Acta Medica Okayama 0021-9258 284 21 2009 Overexpression of REIC/Dkk-3 in Normal Fibroblasts Suppresses Tumor Growth via Induction of Interleukin-7 14236 14244 EN Masakiyo Sakaguchi Ken Kataoka Fernando Abarzua Ryuta Tanimoto Masami Watanabe Hitoshi Murata Swe Swe Than Kaoru Kurose Yuji Kashiwakura Kazuhiko Ochiai Yasutomo Nasu Hiromi Kumon Nam-ho Huh We previously showed that the tumor suppressor gene REIC/Dkk-3, when overexpressed by an adenovirus (Ad-REIC), exhibited a dramatic therapeutic effect on human cancers through a mechanism triggered by endoplasmic reticulum stress. Adenovirus vectors show no target cell specificity and thus may elicit unfavorable side effects through infection of normal cells even upon intra-tumoral injection. In this study, we examined possible effects of Ad-REIC on normal cells. We found that infection of normal human fibroblasts (NHF) did not cause apoptosis but induced production of interleukin (IL)-7. The induction was triggered by endoplasmic reticulum stress and mediated through IRE1 alpha, ASK1, p38, and IRF-1. When Ad-REIC-infected NHF were transplanted in a mixture with untreated human prostate cancer cells, the growth of the cancer cells was significantly suppressed. Injection of an IL-7 antibody partially abrogated the suppressive effect of Ad-REIC-infected NHF. These results indicate that Ad-REIC has another arm against human cancer, an indirect host-mediated effect because of overproduction of IL-7 by mis-targeted NHF, in addition to its direct effect on cancer cells. No potential conflict of interest relevant to this article was reported.

Nature Publishing Group Acta Medica Okayama 0929-1903 17 7 2010 Potent antitumor effects of combined therapy with a telomerase-specific, replication-competent adenovirus (OBP-301) and IL-2 in a mouse model of renal cell carcinoma 484 491 EN P Huang H Kaku J Chen Y Kashiwakura T Saika Y Nasu Y Urata T Fujiwara M Watanabe H Kumon OBP-301 (a telomerase-specific, replication-competent adenovirus with hTERT promoter) was constructed in a previous study and it showed a strong anticancer effect by inducing cell lysis in human lung and prostate cancer cells. This study investigated the effectiveness of a combination therapy of OBP-301 and interleukin-2 (IL-2) in a mouse model of renal cell carcinoma (RCC). The cell-killing effect of OBP-301 was confirmed in vitro in the RENCA cancer cells. In in vivo experiment, luciferase-expressing RENCA cells were implanted in the left kidney and lung of BALB/c mice to prepare the RCC metastatic model. The animals were randomly divided into four treatment groups: PBS, IL-2 alone, OBP-301 alone and the combination. The analyses of orthotopic tumor weight, lung metastasis and luciferin-stained tumor images 14 days after each treatment showed significant tumor growth inhibition in the combination group in comparison with that in the OBP-301- or IL-2-treated groups. In addition, the percentage of regulatory T-cells (Tregs) in the combination group was significantly suppressed in comparison with that in the PBS and single-agent treatment groups. The outcomes of this study suggest that tumor-specific oncolytic immunovirotherapy may become an attractive strategy for the treatment of human RCC. No potential conflict of interest relevant to this article was reported.

Acta Medica Okayama 0020-7136 126 7 2010 Down-regulation of BiP/GRP78 sensitizes resistant prostate cancer cells to gene-therapeutic overexpression of REIC/Dkk-3 1562 1569 EN Ryuta Tanimoto Masakiyo Sakaguchi Fernando Abarzua Ken Kataoka Kaoru Kurose Hitoshi Murata Yasutomo Nasu Hiromi Kumon Nam-Ho Huh We have recently shown that an adenovirus carrying REIC/Dkk-3 (Ad-REIC) exhibits a potent tumor-specific cell-killing function for various human cancers. It has also become evident that some human cancers are resistant to Ad-REIC-induced apoptosis. The aim of the present study was to determine the molecular mechanisms of resistance to Ad-REIC. First, we isolated resistant clones from a human prostate cancer cell line, PC3, after repeated exposure to Ad-REIC. Infection efficiency of the adenovirus vector and expression level of REIC/Dkk-3 in the resistant clones were similar to those in the parental PC3 cells. By screening for alteration in levels and functional status of proteins involved in Ad-REIC-induced apoptosis, we found that BiP/GRP78, an ER-residing chaperone protein, was expressed at higher levels consistently among resistant cells. Expression levels of BiP and rates of apoptosis induced by Ad-REIC were inversely correlated. Down-regulation of BiP with siRNA sensitized the resistant cells to Ad-REIC in vivo as well as in culture. These results indicate that BiP is a major determinant of resistance to Ad-REIC-induced apoptosis. Thus BiP is useful for diagnosis of inherent and acquired resistance of cancers and also as a target molecule to overcome resistance to the gene therapeutic Ad-REIC. No potential conflict of interest relevant to this article was reported.