bluuebunny/crossref_metadata_2025 huggingface dataset:
Tumor hypoxia: A target for selective cancer therapy
Authors: Kizaka‐Kondoh Shinae , Inoue Masahiro , Harada Hiroshi , Hiraoka Masahiro
Published: August 2005

Tumor hypoxia has been considered to be a potential therapeutic problem because it renders solid tumors more resistant to sparsely ionizing radiation (IR) and chemotherapeutic drugs. Moreover, recent laboratory and clinical data have shown that tumor hypoxia is also associated with a more malignant phenotype and poor survival in patients suffering from various solid tumors. Therefore, selective targeting of hypoxic tumor cells has been explored, and since severe hypoxia (pO2<0.33%, 2.5 mmHg) does not occur in normal tissue, tumor hypoxia could be exploited for therapeutic advantage. However, the following three characteristics of hypoxic tumor regions present obstacles in targeting hypoxic cells. First, it is difficult to deliver a sufficient amount of drug to a region that is remote from blood vessels. Second, one must specifically target hypoxic tumor cells while sparing normal well‐oxygenated tissue from damage. Finally, the severely hypoxic tumor cells to be attacked have often stopped dividing. Therefore, high delivery efficiency, high specificity and selective cytotoxicity are all necessary to target and combat hypoxic tumor cells. The current review describes progress on the biological aspects of tumor hypoxia and provides a compilation of the recent molecular approaches used to target hypoxic tumors. These approaches include our work with a unique hypoxia‐targeting protein drug, TOP3, with which we have sought to address the above three difficulties.
The role of Gab family scaffolding adapter proteins in the signal transduction of cytokine and growth factor receptors
Authors: Nishida Keigo , Hirano Toshio
Published: August 2005

The Grb2‐associated binder (Gab) family adapter proteins are scaffolding adapter molecules that display sequence similarity with Drosophila DOS (daughter of sevenless), which is a substrate for the protein tyrosine phosphatase Corkscrew. Gab proteins contain a pleckstrin homology (PH) domain and binding sites for SH2 and SH3 domains. A number of studies in multiple systems have implicated Gab in signaling via many different types of receptors, such as growth factor, cytokine, and antigen receptors, and via oncoproteins. Recent studies of Gab1 and Gab2 knockout mice have clearly indicated an important role for Gabs in vivo. Gab1‐deficient mice die as embryos with multiple defects in placental, heart, skin, and muscle development. Gab2‐deficient mice are viable, but have a defect in the mast cell lineages and in allergic reactions. Given the apparently central role played by Gab signaling via many receptors, delineating the precise mechanism(s) of Gab‐mediated signaling is critical to understanding how cytokines, growth factors, and oncoproteins mediate a variety of biological activities: cell growth, differentiation, survival and malignant transformation.
Generation of mature dendritic cells fully capable of T helper type 1 polarization using OK‐432 combined with prostaglandin E2
Authors: Sato Marimo , Takayama Takuya , Tanaka Hiroaki , Konishi Juichiro , Suzuki Toshihiro , Kaiga Teruo , Tahara Hideaki
Published: August 2005

Dendritic cell (DC) administration appears to be a very promising approach for the immunotherapy of cancer. The results of clinical studies have suggested that the nature and the magnitude of antitumor immune responses are critically affected by DC functions, including production of T helper type 1 (Th1)‐inducing cytokines, activation of T cell subsets and natural killer (NK) cells, and migration from peripheral tissues to the T cell area of the draining lymph nodes. Administration of immature DCs could fail to fully stimulate antigen‐specific immune responses and might induce tolerance under some conditions. In this study, we developed a method to obtain fully mature DCs, and we compared in detail the DCs thus obtained with those obtained using a maturation stimulus termed monocyte‐derived medium (MCM)‐mimic, which is a mixture of recombinant cytokines and prostaglandin E2 (PGE2) mimicking the components of monocyte‐conditioned medium. Using DCs derived from monocytes of advanced cancer patients in this study, we found that DCs stimulated with OK‐432 alone showed phenotypes similar to those of mature DCs induced using MCM‐mimic, though with better secretion of IL‐6 and IL‐12. However, these DCs were found to have poor migratory capacity associated with the marginal expression of CCR7. When OK‐432 was combined with PGE2, the CCR7 expression and migratory capacity of DCs were significantly improved without impairing other immuno‐stimulatory functions. These results suggest that stimulation with the combination of OK‐432 and PGE2 could be applicable as an alternative to MCM‐mimic in clinical trials which require fully matured DCs to induce Th1‐type immune responses against tumor cells even in patients with advanced cancer.
Stem cells and gastric cancer: Role of gastric and intestinal mixed intestinal metaplasia
Authors: Tatematsu Masae , Tsukamoto Tetsuya , Inada Kenichi
Published: August 2005

All of the different types of stomach epithelial cells are known to be derived from a single progenitor cell in each gland. Similarly, cancers develop from single cells, based on data from clonality analysis in C3H/HeN ↔ BALB/c chimeric mice. Using gastric and intestinal epithelial cell markers, intestinal metaplasia (IM) can be divided into two major types: a gastric and intestinal (GI) mixed type, and a solely intestinal (I) type. Ectopic expression of Cdx genes and down‐regulation of Sox2 in isolated single GI mixed IM glands suggests abnormal differentiation of stem cells that can produce both gastric (G) and I type cells. Similarly, phenotypic expression of gastric cancer cells of each histological type can be clearly classified into G and I type epithelial cells. The heterogeneity of phenotypic expression of gastric cancer cells in individual cancers is assumed to reflect this intrinsic potential for differentiation in two directions. Gastric cancers at early stages, independent of the histological type, mainly consist of G type cells, and phenotypic shift from G to I type expression is clearly observed with progression. The data thus suggest IM may not be a preneoplastic change in gastric carcinoma, but rather that cells of the I type may appear independently in the gastric mucosa in IM and in gastric cancers. Intestinalization of gastric mucosa and cancer cells may represent a kind of homeotic transformation. Whether disturbance of the regulation of Sox2 and Cdx genes may be of importance to the biological behavior of gastric cancers should therefore be clarified in future studies. (Cancer Sci 2003; 94: 135–141)
Effect of early eradication on Helicobacter pylori‐related gastric carcinogenesis in Mongolian gerbils
Authors: Nozaki Koji , Shimizu Nobuyuki , Ikehara Yuzuru , Inoue Manami , Tsukamoto Tetsuya , Inada Ken‐ichi , Tanaka Harunari , Kumagai Toshiko , Kaminishi Michio , Tatematsu Masae
Published: August 2005

Helicobacter pylori (Hp) infection and gastric carcinogenesis are known to have a close relationship, but the effect of eradication of Hp on Hp‐related gastric carcinogenesis has not been fully studied experimentally. To evaluate the effect of eradication in gastric carcinogenesis, an experimental model with eradication in the early, middle or late period was studied using Hp‐infected and N‐methyl‐N‐nitrosourea (MNU)‐treated Mongolian gerbils. The animals were divided into seven groups: group A (MNU+Hp+ eradication at 15 w), group B (MNU+Hp+eradication at 35 w), group C (MNU+Hp+eradication at 55 w), group D (MNU+Hp), group E (MNU), group F (Hp) and group G (control). The tumor incidences at week 75 in the early (group A), middle (group B) and late (group C) eradicated groups were 6.7%, 27.3% and 38.2%, respectively. The incidence of 56.3% in the non‐eradicated group was the highest (group D). Incidences in group E, group F and group G were 6.3%, 0.0% and 0.0%, respectively. The tumor incidences were related to the period of inflammatory status induced by Hp infection. Hp infection strongly enhanced gastric carcinogenesis initiated with a chemical carcinogen, and following eradication at an early period this enhancing effect was effectively reduced. Eradication at an early stage of inflammation might be effective in preventing Hp‐related gastric carcinogenesis. (Cancer Sci 2003; 94: 235–239)
Heparanase and tumor invasion patterns in human oral squamous cell carcinoma xenografts
Authors: Kurokawa Hitoshi , Katsube Ken‐ichi , Podyma Katarzyna A. , Ikuta Minoru , Iseki Hachirou , Nakajima Motowo , Akashi Takumi , Omura Ken , Takagi Minoru , Yanagishita Masaki
Published: August 2005

The role of heparanase, an endo‐β‐glucuronidase specifically degrading heparan sulfate (HS) glycosaminoglycans, in the mechanism of cancer cell invasion was investigated. Three human oral squamous cell carcinoma (SCC) cell lines (i.e., HSC‐2, HSC‐3 and LMF4), exhibiting various degrees of invasiveness to their surrounding tissues, were xenografted to the tongue of SCID mice in order to establish experimental cancer foci. Cancer cells and their surrounding tissues were examined for the expression of heparanase mRNA by an in situ hybridization technique, and for various basement membrane (BM)‐associated molecules (i.e., perlecan, laminins and type IV collagen) by immunohistochemical procedures. BM structures surrounding cancer tissues were also examined by electron microscopy. Increasing levels of heparanase mRNA expression were observed with the progression of cancer invasiveness, as manifested by the destruction of BM structures. Enhanced heparanase enzyme activities in cancer tissues with more invasive properties were demonstrated by the disappearance of HS glycosaminoglycans in the face of retained HS pro‐teoglycan core proteins. These results demonstrated a positive correlation between the heparanase enzyme activities and the invasiveness of human oral SCC. The roles of heparanase in cancer cell invasion were not precisely clarified by the present morphological study, but the enhanced heparanase activity in an early phase of BM destruction by cancer cells suggested the participation of this enzyme from the early phase of cancer invasion. (Cancer Sci 2003; 94: 277–285)
Tumor regression by combined immunotherapy and hyperthermia using magnetic nanoparticles in an experimental subcutaneous murine melanoma
Authors: Ito Akira , Tanaka Kouji , Kondo Kazuyoshi , Shinkai Masashige , Honda Hiroyuki , Matsumoto Kazuhiko , Saida Toshiaki , Kobayashi Takeshi
Published: August 2005

Immunotherapy (IT) has become an accepted therapeutic modality. We previously reported that intracellular hyperthermia (IH) using magnetic nanoparticles induces antitumor immunity. We undertook these studies in order to study the combined effects of IT and IH on melanoma. Magnetite cationic liposomes (MCLs) have a positive surface charge and generate heat in an alternating magnetic field (AMF) due to hysteresis loss. MCLs were injected into a B16 melanoma nodule in C57BL/6 mice, which were subjected to AMF for 30 min. The temperature at the tumor reached 43°C and was maintained by controlling the magnetic field intensity. At 24 h after IH, interleukin‐2 (IL‐2) or granulocyte macrophage‐colony stimulating factor (GM‐CSF) was injected directly into the melanoma. Mice were divided into six groups: group I (control), group II (IH), group III (IL‐2), group IV (GM‐CSF), group V (IH+IL‐2), and group VI (IH+GM‐CSF). Complete regression of tumors was observed in mice of groups V and VI (75% (6/ 8) and 40% (4/10) of the mice, respectively), while no tumor regression was observed in mice of the other groups. This study supports the combined use of IT and IH using MCLs in patients with advanced malignancies. (Cancer Sci 2003; 94: 308–313)
NK4 (HGF‐antagonist/angiogenesis inhibitor) in cancer biology and therapeutics
Authors: Matsumoto Kunio , Nakamura Toshikazu
Published: August 2005

Invasion and subsequent establishment of metastasis are devastating events for patients with cancer, but past therapeutic approaches have paid relatively little attention to these important issues. Hepatocyte growth factor (HGF) and its receptor, the c‐Met tyrosine kinase, play roles in cancer invasion and metastasis in a wide variety of tumor cells. Activation of the c‐Met receptor integrates multiple signal transduction pathways involved in cell‐cell and cell‐matrix interactions, cellular migration, and breakdown of the extracellular scaffold. Paracrine activation of the c‐Met receptor by stromal‐derived HGF mediates tumor‐stromal interactions that facilitate invasion and metastasis. Likewise, aberrant expression of the c‐Met receptor and autocrine or mutational activation of c‐Met receptor tyrosine kinase are closely associated with the progression of malignant tumors. Based on this background, NK4, a competitive antagonist of HGF‐c‐Met association was prepared so as to block cancer invasion and metastasis. NK4, an internal fragment of HGF, binds to but does not activate the c‐Met receptor, thereby competitively antagonizing the biological activities of HGF. Unexpectedly, NK4 was subsequently shown to be an angiogenesis inhibitor as well, and this angioinhibitory activity is independent of its action as an HGF‐antagonist. Importantly, NK4 protein or NK4 gene therapy have been shown to inhibit tumor invasion, metastasis and angiogenesis, effectively converting malignant tumors into benign tumors. Targeting tumor invasion‐metastasis and angiogenesis with NK4 seems to have considerable therapeutic potential for cancer patients. (Cancer Sci 2003; 94: 321–327)
Predictive value of expression of P53, Bcl‐2 and lung resistance‐related protein for response to chemotherapy in non‐small cell lung cancers
Authors: Harada Toshiyuki , Ogura Shigeaki , Yamazaki Koichi , Kinoshita Ichiro , Itoh Tomoo , Isobe Hiroshi , Yamashiro Katsushige , Dosaka‐Akita Hirotoshi , Nishimura Masaharu
Published: August 2005

Chemoresistance is a major problem in the chemotherapy of non‐small cell lung cancers (NSCLCs). Several mechanisms are thought to be involved in drug resistance, including those associated with apoptosis, drug transport and detoxification. Here, we investigated the predictive value of P53, Bcl‐2 and lung resistance‐related protein (LRP) expression for response to platinum‐based chemotherapy, using transbronchial biopsy (TBB) specimens from patients with NSCLC. We evaluated TBB specimens from 57 patients with NSCLC who had not previously been treated with either chemotherapy or radiotherapy before TBB, and who were treated with systemic platinum‐based chemotherapy. The specimens included 33 adenocarcinomas, 22 squamous cell carcinomas and two large cell carcinomas. One to 6 courses of chemotherapy were administered. Expression of P53, Bcl‐2 and LRP was analyzed by immunohistochemistry using TBB specimens. Positive expression of P53, Bcl‐2 and LRP was observed in 28 (49%), 41 (71%) and 42 (73%) of the 57 NSCLCs, respectively. P53 expression correlated significantly with response to chemotherapy in nonsquamous cell carcinomas, including adenocarcinomas and large cell carcinomas (response rates, 38% and 6% for patients with P53‐positive and P53‐negative tumors, respectively, P=0.03). LRP expression significantly correlated inversely with response to chemotherapy in squamous cell carcinomas (response rates, 33% and 100% for patients with LRP‐positive and LRP‐negative tumors, respectively, P=0.02). Bcl‐2 expression did not correlate with response to chemotherapy. These findings indicate that im‐munostaining for P53 and LRP using TBB specimens may be useful for dividing patients with NSCLC into chemoresponsive and chemoresistant groups. (Cancer Sci 2003; 94: 394–399)
Loss of heterozygosity on chromosome 6q correlates with decreased thrombospondin‐2 expression in human salivary gland carcinomas
Authors: Kishi Munehiro , Nakamura Mitsutoshi , Nishimine Masayoshi , Ishida Eiwa , Shimada Keiji , Kirita Tadaaki , Konishi Noboru
Published: August 2005

Since loss of heterozygosity (LOH) on the long arm of chromosome 6q is frequently observed in salivary gland carcinomas, we examined 28 salivary gland carcinomas using 24 microsat‐ellite markers mapping to 6q15–27 to identify the commonly deleted region that we felt might contain one or more tumor suppressor genes. LOH was detected in at least one locus in 10 of 28 tumors (35.7%). The most frequently deleted regions occurred between D6S1581 and D6S305 (LOH cluster region 1 (LCR1) and between D6S297 and D6S1590 (LCR2). LOH was observed in 60% of adenoid cystic carcinomas (ACC) and in 57.1% of mucoepider‐moid carcinomas (MEC), but was not observed in any locus in any other histological subtypes studied. The gene encoding for thrombospondin‐2 (TSP‐2) is located in LCR2 and 8 of 9 tumors demonstrating LOH in this region also showed significantly decreased TSP‐2 expression by immunohistochemistry. As TSP‐2 is a potent inhibitor of tumor growth and angiogenesis, we examined whether TSP‐2 expression correlated to microvascular angiogenesis in these tumors and discovered that microvessel counts were significantly higher in lesions with decreased TSP‐2 expression (P=0.02). Our results suggest that 6q LOH may be a significant event in salivary gland carcinogenesis, particularly in ACC and MEC, and that the correlated decrease of TSP‐2 expression also plays a critical role.
Aberrant methylation of the vascular endothelial growth factor receptor‐1 gene in prostate cancer
Authors: Yamada Yasushi , Watanabe Masatoshi , Yamanaka Mikio , Hirokawa Yoshifumi , Suzuki Hiroyoshi , Takagi Akimitsu , Matsuzaki Takeshi , Sugimura Yoshiki , Yatani Ryuichi , Shiraishi Taizo
Published: August 2005

Transcriptional silencing of cancer‐related genes by DNA methylation is observed in various cancers. To identify genes controlled by methylation in prostate cancer, we used cDNA microarray analysis to investigate gene expression in prostate cancer cell lines LNCaP and DU145 treated with a methyltransferase inhibitor alone or together with a histone deacetylase inhibitor. We detected significant changes (3.4–5.7%) in gene expression in prostate cancer cell lines with the drug treatments. Among the affected genes, that for the vascular endothelial growth factor receptor 1 (VEGFR‐1) was re‐expressed in LNCaP and DU145 after the drug treatments. Bisulfite sequencing revealed the promoter and exon 1 of the VEGFR‐1 to be hypermethylated in the cell lines. These results support the idea that methylation is associated with loss of VEGFR‐1 mRNA expression in prostate cancer cell lines. Combined bisulfite restriction analysis (COBRA) showed the gene to be methylated in 24 (38.1%) of 63 primary local prostate cancer samples, while in all 13 benign prostate samples it was not. These findings indicate that methylation of VEGFR‐1 is related with prostatic carcinogenesis.
The gene expression of hepatic proteins responsible for DNA repair and cell proliferation in tamoxifen‐induced hepatocarcinogenesis
Authors: Kasahara Toshihiko , Kuwayama Chitose , Hashiba Masamichi , Harada Tsuyoshi , Kakinuma Chihaya , Miyauchi Makoto , Degawa Masakuni
Published: August 2005

Altered gene expression of the DNA repair‐ and cell proliferation‐associated proteins/enzymes was examined during the process of tamoxifen‐induced hepatocarcinogenesis in female Sprague‐Dawley rats. When rats were treated by gavage with a single dose of tamoxifen (20 mg/kg body weight) or with the same dose given at 24‐h intervals for 2, 12 or 52 weeks, no histopathological change was observed in the liver after 2 weeks. Pathologically altered cell foci and placental form of glutathione‐S‐transferase (GST‐P)‐positive foci were observed in the liver after 12 weeks of treatment. Treatment for 52 weeks resulted in the formation of liver hyperplastic nodules that strongly expressed GST‐P. During the process of carcinogenesis, changes in hepatic gene expression of DNA repair proteins/enzymes (XPA and XPC, xeroderma pigmentosum complementation groups A and C, respectively; APE, apurinic/apyrimidinic endonuclease) and of cell proliferation‐associated proteins (c‐myc; PCNA, proliferating cell nuclear antigen; cyclin D1, cyclin B, and p34cdc2) were examined by RT‐PCR. The gene expression ofXPAandAPEwas increased by the tamoxifen treatment for 2 or 12 weeks, but no increase was observed after the 52‐week treatment. In addition, no significant change inXPCgene expression occurred at any period examined. The gene expression ofc‐myc, PCNA, andcyclin D1was increased in a time‐dependent fashion up to 12 weeks of treatment, and this increase was maintained up to 52 weeks of treatment. The gene expression ofcyclin Bandp34cdc2was increased after the 1‐day treatment, reverted to the control level at 2 and 12 weeks of treatment, and was remarkably increased after the 52‐week treatment. In the present study, we demonstrate the altered gene expression of various proteins/enzymes involved in DNA repair, cell growth and the cell cycle during the process of tamoxifen‐induced hepatocarcinogenesis. We discuss the relationship between the altered gene expression and hepatocarcinogenesis.
Promoter hypermethylation of tumor suppressor and tumor‐related genes in non‐small cell lung cancers
Authors: Yanagawa Naoki , Tamura Gen , Oizumi Hiroyuki , Takahashi Nobumasa , Shimazaki Yasuhisa , Motoyama Teiichi
Published: August 2005

Aberrant methylation of promoter CpG islands is known to be a major inactivation mechanism of tumor suppressor and tumor‐related genes. To determine the clinicopathological significance of gene promoter methylation in non‐small cell lung cancer (NSCLC), we examined the promoter methylation status of the APC, DAP‐kinase, E‐cadherin, GSTP1, hMLH1, p16, RASSF1A and RUNX3 genes in 75 NSCLCs and corresponding non‐neoplastic lung tissues by methylation‐specific PCR (MSP). The frequencies of methylation in NSCLCs and corresponding non‐neoplastic lung tissues were: 37% (28 of 75) and 48% (36 of 75) for APC, 28% (21 of 75) and 13% (10 of 75) for DAP‐kinase, 29% (22 of 75) and 15% (11 of 75) for E‐cadherin, 1% (1 of 75) and 0% (0 of 75) for GSTP1, 7% (5 of 75) and 0% (0 of 75) for hMLH1, 31% (23 of 75) and 0% (0 of 75) for p16, 43% (32 of 75) and 4% (3 of 75) for RASSF1A, and 20% (15 of 75) and 3% (2 of 75) for RUNX3, respectively. Methylation of p16 was more frequent in squamous cell carcinomas than in adenocarcinomas (P<0.05), and was associated with tobacco smoking (P<0.05). On the contrary, methylation of APC and RUNX3 was more frequent in adenocarcinomas than in squamous cell carcinomas (P<0.05). Thus, a different set of genes is thought to undergo promoter methylation, which leads to the development of different histologies. In addition, methylation of p16, RASSF1A and RUNX3 was mostly cancer‐specific (P<0.05), and may be utilized as a molecular diagnostic marker of NSCLCs.
Vascular endothelial growth factor receptor‐2: Its unique signaling and specific ligand, VEGF‐E
Authors: Shibuya Masabumi
Published: August 2005

Vascular endothelial growth factor receptor‐2 (VEGFR‐2/KDR/Flk‐1) is a high‐affinity receptor for vascular endothelial growth factor‐A (VEGF‐A), and mediates most of the endothelial growth and survival signals from VEGF‐A. VEGFR‐2 has a typical tyrosine kinase receptor structure with seven immunoglobulin (Ig)‐like domains in the extracellular region, as well as a long kinase insert in the tyrosine kinase domain. It utilizes a unique signaling system for DNA synthesis in vascular endothelial cells, i.e. a phospholipase Cγ‐protein kinaseC‐Raf‐MAP kinase pathway. Although VEGF‐A binds two receptors, VEGFR‐1 and ‐2, a newly isolated ligand VEGF‐E (Orf‐virus‐derived VEGF) binds and activates only VEGFR‐2. Transgenic mice expressing VEGF‐ENZ‐7 showed a dramatic increase in angiogenesis with very few side effects (such as edema and hemorrhagic spots), suggesting strong angiogenic signaling and a potential clinical utility of VEGF‐E. VEGF family members bear three loops produced via three intramolecular disulfide bonds, and cooperation between loop‐1 and loop‐3 is necessary for the specific binding and activation of VEGFR‐2 for angiogenesis. As it directly upregulates tumor angiogenesis, VEGFR‐2 is an appropriate target for suppression of solid tumor growth using exogenous antibodies, small inhibitory molecules and in vivo stimulation of the immune system.
Induction of tube formation by angiopoietin‐1 in endothelial cell/fibroblast co‐culture is dependent on endogenous VEGF
Authors: Saito Momomi , Hamasaki Maho , Shibuya Masabumi
Published: August 2005

The angiopoietin‐1 (Ang1)/Tie2 receptor system is known to be important for angiogenesis and vascular remodeling. However, its contribution to the survival and morphogenesis of endothelial cells is still not well elucidated. In this study, we analyzed the role of the Ang1/Tie2 pathway in cell survival and tube formation using a human umbilical vein endothelial (HUVE) cell and fibroblast co‐culture system. In this system, which mimics angiogenesis in vivo, fibroblasts secrete a basal level of vascular endothelial growth factor (VEGF), and Ang1 stimulated tube formation. However, anti‐VEGF or anti‐VEGF receptor‐2 neutralizing antibody blocked the Ang1‐induced tube formation. Furthermore, other angiogenic factors such as hepatic growth factor (HGF) and basic fibroblast growth factor (bFGF) showed the same pheno‐type as Ang1, i.e., a stimulatory effect only in the presence of endogenous VEGF. The Ang1‐promoted tube formation was mainly due to suppression of HUVE cell apoptosis in a PI3‐kinase‐dependent manner. These findings suggest that Ang1 stimulates tube formation in vivo via the PI3‐kinase/Akt pathway, but this effect takes place only in a VEGF‐dependent manner.
What are the reasons for negative phase III trials of molecular‐target‐based drugs?
Authors: Saijo Nagahiro
Published: August 2005

The results of molecular‐biological studies of cancer are changing the way we diagnose and treat cancer. Target‐based drug discovery selects agents for development based on their mechanisms of action. The interaction between target‐based drugs and their targets can be described by classical drug‐receptor theory. Clinical trials have demonstrated that some effective target‐based drugs induce apoptosis, even though they are considered to be cyto‐static. Numerous phase III trials of target‐based drugs have been conducted. Although some have yielded strongly positive results, the majority of the results have been negative. This article seeks to clarify the value of molecular‐target‐based therapy and to discuss the reasons for negative results in phase III trials. The importance of proof‐of‐principle studies is stressed throughout preclinical and clinical trials of molecular‐target‐based drugs.
TRAIL and its receptors as targets for cancer therapy
Authors: Yagita Hideo , Takeda Kazuyoshi , Hayakawa Yoshihiro , Smyth Mark J. , Okumura Ko
Published: August 2005

Tumor necrosis factor (TNF)‐related apoptosis‐inducing ligand (TRAIL) is a member of the TNF family of cytokines, which can induce apoptotic cell death in a variety of tumor cells by engaging the death receptors DR4 and DR5, while sparing most normal cells. Preclinical studies in mice and non‐human primates have shown the potential utility of recombinant soluble TRAIL and agonistic anti‐DR5 or DR4 antibodies for cancer therapy. Moreover, we have recently revealed a vital role for endogenously expressed TRAIL in immunosurveillance of developing and meta‐static tumors. In this review, we summarize recent knowledge about TRAIL and its receptors as promising targets for cancer therapy.
Histological and immunohistochemical observations of mucin‐depleted foci (MDF) stained with Alcian blue, in rat colon carcinogenesis induced with 1,2‐dimethylhydrazine dihydrochloride
Authors: Yoshimi Naoki , Morioka Takamitsu , Kinjo Tatsuya , Inamine Morihiko , Kaneshiro Tatsuya , Shimizu Takahiro , Suzui Masumi , Yamada Yasuhiro , Mori Hideki
Published: August 2005

The usefulness of mucin‐depleted foci (MDF), which have recently been proposed as a new preneoplastic biomarker in rat colon carcinogenesis, was histologically investigated in rat colonic tissues treated with 1,2‐dimethylhydrazine dihydrochloride (DMH). The relationship among aberrant crypt foci (ACF), MDF and β‐catenin accumulated crypts (BCAC) was examined by comparing the corresponding computer‐captured images. Twelve male F344 rats were given DMH s.c. at a dose of 40 mg/kg body weight, once a week for 2 weeks, and randomly divided into two groups. Rats in group 1 were given normal drinking water, while those in group 2 were given drinking water containing indomethacin (IND) at 16 ppm for 6 weeks. All animals were sacrificed 8 weeks after the first DMH treatment. The resected colons were fixed in 10% formalin, and stained with Alcian blue for observation of ACF and MDF. Histological and immunohistochemical analysis revealed that the numbers of ACF, MDF and overlapping lesions in group 2 (treated with IND) were significantly decreased, compared with those in group 1. The number of BCAC in group 2 was also significantly lower than that in group 1. The reduction (61.5%) of MDF by IND was much greater than that (29.3%) of ACF. Analyses of the computer‐captured images indicated that MDF had more frequent dysplastic changes and overexpression of β‐catenin than did ACF. MDF having over 4 crypts or MDF with the appearance of ACF corresponded well to BCAC. These results suggest that MDF may be useful as an early biomarker in colon carcinogenesis.
Comparison of genetic aberrations in CD10+ diffused large B‐cell lymphoma and follicular lymphoma by comparative genomic hybridization and tissue‐fluorescence in situ hybridization
Authors: Zhang Xiaohua , Karnan Sivasundaram , Tagawa Hiroyuki , Suzuki Ritsuro , Tsuzuki Shinobu , Hosokawa Yoshitaka , Morishima Yasuo , Nakamura Shigeo , Seto Masao
Published: August 2005

CD10 is one of the hallmarks of germinal center B‐cells where follicular lymphomas (FL) originate. It has not been clearly established, however, whether CD10+ diffuse B‐cell lymphomas (DLBCL) are genetically similar to FL. We therefore examined 19 CD10+DLBCL and 40 FL by means of comparative genomic hybridization (CGH) and tissue‐fluorescence in situ hybridization (T‐FISH). Chromosomal imbalance was more frequently detected in CD10+DLBCLs (19/19) than in FLs (24/40). Significant differences were found in eight frequently imbalanced regions, namely those with gains of chromosomes 7q and 12 and those with losses of chromosomes 1p, 4p, 6q, 15q, 16p and 17. Amplification of the 3q region where BCL6 is located is reported to occur frequently in DLBCL, but it was only found in one of the 19 CD10+DLBCL cases we examined. The involvement of t(14;18) in CD10+DLBCL (31%) and in FL (73%) was significantly different (P=0.0064). The CGH pattern of CD10+DLBCL with t(14;18) was also different from that of FL with t(14;18). Taken together, our results indicate that CD10+DLBCL constitutes a unique subtype entity with genetic characteristics significantly different from those of FL and DLBCL.
Overexpression of the Wilms' tumor gene WT1 in primary astrocytic tumors
Authors: Oji Yusuke , Suzuki Tsuyoshi , Nakano Yoko , Maruno Motohiko , Nakatsuka Shin‐ichi , Jomgeow Tanyarat , Abeno Sakie , Tatsumi Naoya , Yokota Asumi , Aoyagi Sayaka , Nakazawa Tsutomu , Ito Ken , Kanato Keisuke , Shirakata Toshiaki , Nishida Sumiyuki , Hosen Naoki , Kawakami Manabu , Tsuboi Akihiro , Oka Yoshihiro , Aozasa Katsuyuki , Yoshimine Toshiki , Sugiyama Haruo
Published: August 2005

Expression of the Wilms' tumor gene WT1 in primary astrocytic tumors was examined using a quantitative real‐time reverse transcriptase‐polymerase chain reaction (RT‐PCR) or immunohistochemistry. Real‐time RT‐PCR showed that WT1 mRNA was expressed at various levels in all of the 25 astrocytic tumors examined. Immunohistochemical analysis showed that WT1 protein was expressed in 5 of 6 low‐grade astrocytic tumors (grade l‐ll) and all of 18 high‐grade ones (grade III‐IV), and that expression levels of WT1 protein in high‐grade tumors were significantly higher than those in low‐grade ones. WT1 protein was not detected in the normal glial cells contained in the tumor specimens. Furthermore, treatment with WT1 antisense oligomers specifically inhibited growth of glioblastoma cell lines, U87‐MG, A172, and T‐98G. These results may indicate that the WT1 gene plays an important role in tumorigenesis of primary astrocytic tumors.
Non‐steroidal anti‐inflammatory drugs inhibit cellular proliferation and upregulate cyclooxygenase‐2 protein expression in endometrial cancer cells
Authors: Gao Jingchun , Niwa Kenji , Sun Wenshu , Takemura Masao , Lian Zenglin , Onogi Kyoko , Seishima Mitsuru , Mori Hideki , Tamaya Teruhiko
Published: August 2005

We determined the effects of several non‐steroidal anti‐inflammatory drugs (NSAIDs), aspirin (acetylsalicylic acid, ASA), indomethacin and a cyclooxygenase‐2 (COX‐2)‐selective inhibitor (NS398), on cellular proliferation and regulation of COX‐2 protein expression in endometrial cancer cells in vitro, and investigated their modes of action. All three NSAIDs markedly inhibited the proliferation of Ishikawa, HEC‐1A and AN3CA endometrial cancer cell lines in a time‐ and concentration‐dependent manner. ASA and indomethacin triggered apoptosis in cells of all three lines through release of cytosolic cytochrome c, activation of caspase‐9 and ‐3, and cleavage of poly(ADP‐ribose) polymerase (PARP), but NS398 induced minimal apoptosis only in Ishikawa cells. ASA altered the cell cycle distribution, with G2/M phase accumulation of cells, and induced overexpression of Ki‐67 protein. Both ASA and indomethacin reduced the protein levels of Bcl‐2 and Bcl‐xl, but upregulated those of Bax and Bcl‐xs. COX‐2 protein expression and PGE2 production were upregulated by ASA and indomethacin in all three cell lines. However, NS398 did not alter COX‐2 protein expression or PGE2 production in these cells. These results indicate that NSAIDs inhibit proliferation of endometrial cancer cells independently of the reduction of COX‐2 protein expression. A cytochrome c‐dependent apoptotic pathway and/or cell cycle arrest may contribute to the inhibitory effects of these NSAIDs.
Phenotypic differences of proliferating fibroblasts in the stroma of lung adenocarcinoma and normal bronchus tissue
Authors: Nakamura Naoko , Iijima Tatsuo , Mase Kentaro , Furuya Shuichiroh , Kano Junko , Morishita Yukio , Noguchi Masayuki
Published: August 2005

Fibroblasts in tumor tissue are thought to interact with tumor cells directly and/or indirectly and to have important roles in tumor invasion and metastasis. To characterize the phenotype of proliferating fibroblasts in pulmonary adenocarcinoma, we established short‐term fibroblast cell lines from both normal bronchus and adenocarcinoma tissues obtained from the same patients and compared the gene expression profiles. Four sets of fibroblast cell lines (eight cell lines in total) were used in the analysis. Total RNA was extracted from each cell line and hybridized with 550 cancer‐related RNAs blotted on a cDNA filter array. Five up‐regulated genes and 12 down‐regulated genes (total of 17 genes) were detected in the fibroblast cell lines from the tumor tissues compared with those from normal bronchus. Using real‐time quantitative RT‐PCR methods, the expression profile of each gene was examined; five genes, one up‐regulated (MLH1) and four down‐regulated (Cox1, FGFR4, p120, and Smad3), were confirmed. Furthermore, the protein expression levels of the five genes in the cancerous and normal tissues were examined immunohistochemically, and the up‐regulation of MLH1 and the down‐regulation of Cox1 in cancerous tissue were confirmed in vivo. These results indicate that the proliferating fibroblasts in pulmonary adenocarcinomas are phenotypically different from fibroblasts in normal bronchus tissues.
Establishment of two cell lines from human gastric scirrhous carcinoma that possess the potential to metastasize spontaneously in nude mice
Authors: Yanagihara Kazuyoshi , Tanaka Hiromi , Takigahira Misato , Ino Yoshinori , Yamaguchi Yoshiyuki , Toge Tetsuya , Sugano Kokichi , Hirohashi Setsuo
Published: August 2005

Few experimental studies have been conducted to clarify the mechanism of development of metastasis in scirrhous carcinoma of the stomach. In the present study, we attempted to establish gastric carcinoma cell lines by incubation of cancer cells collected from the body fluids of patients with gastric cancer. At the same time, xenografting of these cells to nude mice was performed. It was found that, of the gastric carcinoma cell lines thus established, two cell lines, designated as HSC‐44PE and HSC‐58, formed s.c. tumors with a high infiltrative potential (often invading the lymphatics around the cancer tissue) when implanted. Metastasis to the lymph nodes and lungs was observed in 20–40% of all the animals, indicating that the two cell lines are also capable of metastasizing spontaneously. Through repeated selection, i.e., repeated cycles of removal, culture, and implantation of the HSC cancer cells from metastatic lesions, we obtained 5 subclones of HSC‐44PE and HSC‐58 (designated as m2509, m2615, m2792, m2917, and m2691), which, when implanted orthotopically, exhibited the following characteristics as compared to the parent cells: (1) a higher percentage take (survival), similar frequency of metastasis, shorter time to metastasis (less than 100 days), and consistent metastasizing potential; (2) a relatively high frequency of metastasis to lymph nodes, including distant metastasis to axillary lymph nodes; (3) the potential to cause occasional bloody ascites; (4) enhanced expression of dysadherin, CD44, and other molecules. This is the first report of cultured scirrhous gastric carcinoma cells showing the potential for spontaneous metastasis.
Survivin as a predictor of cis‐diamminedichloroplatinum sensitivity in gastric cancer patients
Authors: Nakamura Masashi , Tsuji Naoki , Asanuma Koichi , Kobayashi Daisuke , Yagihashi Atsuhito , Hirata Koichi , Torigoe Toshihiko , Sato Noriyuki , Watanabe Naoki
Published: August 2005

Survivin, a member of the inhibitor‐of‐apoptosis family, inhibits apoptosis by blocking caspase‐3 and ‐7 activation. Gastric cancer, which is among the most intractable of malignant tumors, is known for resistance to various drugs, including cis‐diamminedichloroplatinum (CDDP). Since this agent induces apoptosis via caspase‐3 activation, survivin may mediate the drug resistance. We investigated survivin messenger RNA (mRNA) expression in gastric cancers and the relationship between expression and sensitivity to CDDP. Expression of the survivin gene was significantly up‐regulated in gastric cancers compared to the tissues of normal mucosa, atrophic gastritis, and intestinal metaplasia (P<0.0001) as assessed by a quantitative reverse transcription‐polymerase chain reaction (RT‐PCR), and was negatively associated with overall survival of patients who received CDDP‐based chemotherapy. To investigate whether survivin is a resistance factor against CDDP‐induced apoptosis, we transfected wild‐type and dominant‐negative mutants of the survivin gene into gastric cancer cells using a lipofection method. Overexpression of survivin protected MKN45 cells from CDDP‐induced apoptosis. Expression of the dominant‐negative mutant of the survivin gene sensitized NUGC‐3 cells to drug‐induced apoptosis. These results indicate that survivin may be pivotal in the development of gastric cancer and resistance to CDDP, and therefore controlling expression of the survivin gene may be therapeutically useful. (Cancer Sci 2004; 95: 44–51)
Perspectives on cancer immuno‐epidemiology
Authors: Nakachi Kei , Hayashi Tomonori , Imai Kazue , Kusunoki Yoichiro
Published: August 2005

Estimating human cancer risk based on host‐environment interaction is one task of epidemiology, and it has provided indispensable knowledge for prevention of cancer. The recent development of gene‐engineered mice has also provided solid evidence about the relationship between cancer development and immunity. The aim of this review is to discuss the possible contribution of epidemiology to understanding the role of immunity in host defense against cancer, and also to assess the involvement of inflammation in the occurrence of selected cancers. Here we look at the concepts of cancer immunosurveillance and infection‐inflammation‐cancer, and include a brief introduction to recent studies in humans and experimental animal models. It has been postulated for many years that the immune system has the ability to recognize and eliminate nascent transformed cells in the body (so‐called cancer immunosurveillance hypothesis), and this idea has recently obtained strong support from animal experiments. In humans, follow‐up studies among immunosuppressed transplant recipients revealed a remarkably increased risk of not only selected malignancies, but also cancers with no known viral etiology. On the other hand, a prospective cohort study among the general population revealed that individuals with low natural cytotoxic activity of peripheral blood lymphocytes had an increased risk of cancer development. More studies are warranted to allow the construction of a model for the interaction between host immunity, aging, and the environment. The host immune system is also involved in inflammatory responses to pathogen infection: insufficient immune function of the host, or repeated infection, may result in persistent inflammation, where growth/ survival factors continuously act on initiated cells. The combined use of biomarkers will be necessary to define low‐grade persistent inflammation in future cohort studies; and, in addition to these phenotype marker‐based cohort studies, one plausible future direction will be a genomic approach that can be undertaken within cohort studies, looking at the genetic background underlying individual variations in phenotype markers.
Promoter methylation profiling of 30 genes in human malignant melanoma
Authors: Furuta Junichi , Umebayashi Yoshihiro , Miyamoto Kazuaki , Kikuchi Kanako , Otsuka Fujio , Sugimura Takashi , Ushijima Toshikazu
Published: August 2005

Aberrant methylation and demethylation of promoter CpG islands lead to silencing of tumor‐suppressor genes and abnormal expression of normally methylated genes, respectively. Here, we analyzed human melanomas for their methylation and demethylation profiles. Methylation status of core regions in promoter CpG islands was examined for 20 (candidate) tumor‐suppressor genes, 4 genes that are not considered as tumor‐suppressors, but are frequently silenced in human cancers, and 6 normally methylated melanoma antigen genes (MAGEs). Analysis of 13 melanoma cell lines and 2 cultured normal human epidermal melanocytes (HEMs) showed that 9 tumor‐suppressor genes and all 4 non‐tumor‐suppressor genes were methylated in at least 1 cell line, but never in HEMs, and that all 6 MAGE genes were demethylated in 3 to 13 cell lines. Interestingly, we detected no methylation of MGMT, PTEN, MTAP and p27, which were previously reported as silenced in melanomas. Furthermore, 3 genes that were frequently methylated in the cell lines and 6 MAGE genes were analyzed in 25 surgical melanoma samples. RARB, RASSF1A and 3‐OST‐2 were methylated in 5 (20%), 9 (36%) and 14 (56%) samples, respectively. MAGE‐A1, A2, A3, B2, C1 and C2 were demethylated in 9 (36%), 22 (88%), 20 (80%), 7 (28%), 21 (84%) and 16 (64%) samples, respectively. At least 1 gene was methylated in 18 (72%) samples and at least 1 was demethylated in 24 (96%) samples. No correlation between frequent methylation and frequent demethylation was observed. These profiles showed that both aberrant methylation and demethylation occur widely in human melanomas.
Reduced HGF expression in subcutaneous CT26 tumor genetically modified to secrete NK4 and its possible relation with antitumor effects
Authors: Kubota Takeshi , Fujiwara Hitoshi , Amaike Hisashi , Takashima Kazuhiro , Inada Satoshi , Atsuji Kiyoto , Yoshimura Mamoru , Matsumoto Kunio , Nakamura Toshikazu , Yamagishi Hisakazu
Published: August 2005

Tumor‐stromal interactions, which are regulated by stromal‐derived HGF and tumor‐derived HGF inducers, are essential for tumor cell acquisition of such malignant properties as invasion and metastasis. NK4, a proteolytic cleavage product of HGF, has anti‐tumor activities as both an HGF antagonist and an angiogenesis inhibitor. In this study, we examined the in vitro and in vivo behaviors of mouse colon adenocarcinoma CT26 cells modified by gene transfer to secrete NK4, and investigated the influence of NK4 on expression of HGF and HGF inducers associated with tumor‐stromal interactions. In vitro cell proliferation rates of NK4 transfectant (CT26‐NK4) and mock transfectant (CT26‐NEO) were essentially the same, and scattering and invasion were stimulated by HGF in CT26‐NEO, but not in CT26‐NK4. In syngeneic BALB/c female mice, subcutaneous tumor growth of CT26‐NK4 was potently suppressed, and the survival was prolonged significantly. Immunohistochemistry showed significantly decreased micro vessels and increased apoptotic cells in CT26‐NK4 tumor compared with control. Interestingly, HGF, strongly expressed in CT26‐NEO tumor stroma, was reduced in CT26‐NK4. In vitro, conditioned medium of CT26‐NK4 inhibited fibroblast‐derived HGF production, which was increased by that of CT26‐NEO. Moreover, although similar constitutive expression levels of PDGF and TGF‐α (both HGF inducers) were detected in CT26‐NK4 and CT26‐NEO in semiquantitative RT‐PCR analyses, the expression was up‐regulated by HGF in CT26‐NEO, but not CT26‐NK4. These results suggest that NK4 may exert antitumor activities not only by antagonizing HGF, but also by inhibiting HGF amplification via tumor‐stromal interactions. Continuous, abundant NK4 production induced at a tumor site by gene transfer should show multiple antitumor activities with potential therapeutic benefit.
Search for new biomarkers of gastric cancer through serial analysis of gene expression and its clinical implications
Authors: Yasui Wataru , Oue Naohide , Ito Reiko , Kuraoka Kazuya , Nakayama Hirofumi
Published: August 2005

Gastric cancer is one of the most common human cancers and is the second most frequent cause of cancer‐related death in the world. Serial analysis of gene expression (SAGE) is a powerful technique to allow genome‐wide analysis of gene expression in a quantitative manner without prior knowledge of the gene sequences. SAGE on 5 samples of gastric cancer with different histology and clinical stages have created large SAGE libraries of gastric cancer that enable us to identify new cancer biomarkers. Commonly up‐regulated genes in gastric cancer in comparison with normal gastric epithelia included CEACAM6, APOC1 and YF13H12. By comparing gene expression profiles of gastric cancers at early and advanced stages, several genes differentially expressed by tumor stage were also identified, including FUS, CDH17, COL1A1 and COL1A2, which should be novel genetic markers for high‐grade malignancy. Regenerating gene type IV (REGIV) is one of the most up‐regulated genes in a SAGE library of a scirrhous‐type gastric cancer. In vitro studies using RegIV‐transfected cells revealed that RegIV is secreted by cancer cells and inhibits apoptosis, suggesting that RegIV may serve as a novel biomarker and therapeutic target for gastric cancer. Production of RNA aptamers could be a useful approach to establish a detection system in blood. A custom‐made array, named Ex‐STO‐MACHIP, consisting of 395 genes, including highly differentially expressed genes identified by our SAGE and other known genes related to carcinogenesis and chemosensitivity, is useful to study the molecular pathogenesis of gastric cancer and to obtain information about biological behavior and sensitivity to therapy in the clinical setting. Combined analyses of gene expression profile, genetic polymorphism and genetic instability will aid not only cancer detection, but also characterization of individual cancers and patients, leading to personalized medicine and cancer prevention.