bluuebunny/crossref_metadata_2025 huggingface dataset:
Roles of Phosphatidylinositol 3′-Kinase and Mammalian Target of Rapamycin/p70 Ribosomal Protein S6 Kinase in K-Ras-Mediated Transformation of Intestinal Epithelial Cells
Authors: Shao Jinyi , Evers B. Mark , Sheng Hongmiao
Published: September 2005

Phosphatidylinositol 3′-kinase (PI3K) activity is required for Ras- mediated transformation of intestinal epithelial cells (IECs). The mammalian target of rapamycin (mTOR) and its downstream pathways control the translation of specific mRNAs that are required for cell proliferation and transformation. Here, we elucidated the roles of PI3K and mTOR in K-Ras-mediated transformation of IECs (IEC-6). Induction of K-Ras activated PI3K and mTOR in IECs. p70 ribosomal protein S6 kinase activity was induced by K-Ras in a PI3K- and mTOR-dependent manner. K-Ras did not significantly alter the phosphorylation of eukaryotic initiation factor 4E-binding protein 1. Treatment with either LY-294002 or rapamycin inhibited IEC proliferation and resulted in G1 growth arrest. However, it was noted that inhibition of mTOR enhanced K-Ras-mediated morphological transformation and increased invasiveness of IECs in a mitogen-activated protein/extracellular signal-regulated kinase-dependent manner. Furthermore, inhibition of PI3K or mTOR impaired the growth of an array of colon cancer cells. Spindle transformation, reduced E-cadherin, and increased invasiveness were observed in LY-294002-treated Moser cells. Thus, our results suggest that K-Ras-mediated transformation of IECs involves activation of the PI3K/mTOR pathway. Inhibition of PI3K/mTOR activity leads to G1 growth arrest of transformed IECs. On the other hand, inhibition of PI3K or mTOR may induce the epithelial to mesenchymal transdifferentiation of IECs under certain circumstances.
Apoptotic Signaling Pathways Induced by Nitric Oxide in Human Lymphoblastoid Cells Expressing Wild-Type or Mutant p53
Authors: Li Chun-Qi , Robles Ana I. , Hanigan Christin L. , Hofseth Lorne J. , Trudel Laura J. , Harris Curtis C. , Wogan Gerald N.
Published: September 2005

Loss of p53 function by inactivating mutations results in abrogation of NO·-induced apoptosis in human lymphoblastoid cells. Here we report characterization of apoptotic signaling pathways activated by NO· in these cells by cDNA microarray expression and immunoblotting. A p53-mediated transcriptional response to NO· was observed in p53-wild-type TK6, but not in closely related p53-mutant WTK1, cells. Several previously characterized p53 target genes were up-regulated transcriptionally in TK6 cells, including phosphatase PPM1D (WIP1), oxidoreductase homolog PIG3, death receptor TNFRSF6 (Fas/CD95), and BH3-only proteins BBC3 (PUMA) and PMAIP1 (NOXA). NO· also modulated levels of several gene products in the mitochondria-dependent and death-receptor-mediated apoptotic pathways. Inhibitors of apoptosis proteins X-chromosome-linked inhibitor of apoptosis, cellular inhibitor of apoptosis protein-1, and survivin were significantly down-regulated in TK6 cells, but not in WTK1 cells. Smac release from mitochondria was induced in both cell types, but release of apoptosis-inducing factor and endonuclease G was detected only in TK6 cells. Fas/CD95 was increased, and levels of the antiapoptotic proteins Bcl-2 and Bcl-x/L were reduced in TK6 cells. Activation of procaspases 3, 8, 9, and 10, as well as Bid and poly(ADP-ribose) polymerase cleavage, were observed only in TK6 cells. NO· treatment did not alter levels of death receptors 4 and 5, Fas-associated death domain or proapoptotic Bax and Bak proteins in either cell line. Collectively, these data show that NO· exposure activated a complex network of responses leading to p53-dependent apoptosis via both mitochondrial and Fas receptor pathways, which were abrogated in the presence of mutant p53.
Matrix Metalloproteinase-7 Facilitates Insulin-Like Growth Factor Bioavailability through Its Proteinase Activity on Insulin-Like Growth Factor Binding Protein 3
Authors: Miyamoto Shin’ichi , Yano Keiichi , Sugimoto Seiji , Ishii Genichiro , Hasebe Takahiro , Endoh Yasushi , Kodama Keiji , Goya Masato , Chiba Tsutomu , Ochiai Atsushi
Published: September 2005

Matrix metalloproteinase-7 (MMP-7) secreted by cancer cells has been implicated classically in the basement membrane destruction associated with tumor cell invasion and metastasis. Recent epidemiologic studies have established a correlation between high levels of circulating insulin-like growth factor (IGF) and low levels of IGF binding protein 3 (IGFBP-3), and relative risk of developing colon, breast, prostate, and lung cancer, which are known to produce MMP-7. In this study, IGFBP-3 was assessed as a candidate for the physiologic substrate of MMP-7. MMP-7 proteolysis generated four major fragments (26 kDa, 17 kDa, 15.5 kDa, and 15.5 kDa), and two cleavage sites were identified: one at the site of hydrolysis of the K144-I145 peptide bond and one at the R95-L96 peptide bond. The former site is different from the previously reported site of cleavage of IGFBP-3 by other proteases. Addition of IGFBP-3 inhibited IGF-I-mediated IGF type 1 receptor (IGF-IR) phosphorylation and activation of the downstream molecule Akt in BALB/c 3T3 fibroblasts overexpressing human IGF-IR (3T3-IGF-IR) and in two human colon cancer cell lines (COLO201 and HT29). Coincubation of the IGF-I/IGFBP-3 complex with MMP-7 restored IGF-I-mediated IGF-IR phosphorylation and activation of Akt in these cell lines. The IGF-I signal recovered by MMP-7 protected against apoptosis induced by anoikis in 3T3-IGF-IR cells. These results indicate that MMP-7 proteolysis of IGFBP-3 plays a crucial role in regulating IGF-I bioavailability, thereby promoting cell survival. This mechanism may contribute to the tumorigenesis of MMP-7-producing IGF-IR-expressing tumors in the primary site and to organ-specific metastasis in a paracrine manner.
Endometase/Matrilysin-2 in Human Breast Ductal Carcinoma
in Situ
and Its Inhibition by Tissue Inhibitors of Metalloproteinases-2 and -4
Authors: Zhao Yun-Ge , Xiao Ai-Zhen , Park Hyun I. , Newcomer Robert G. , Yan Mei , Man Yan-Gao , Heffelfinger Sue C. , Sang Qing-Xiang Amy
Published: September 2005

Local disruption of the integrity of both the myoepithelial cell layer and the basement membrane is an indispensable prerequisite for the initiation of invasion and the conversion of human breast ductal carcinoma in situ (DCIS) to infiltrating ductal carcinoma (IDC). We previously reported that human endometase/matrilysin-2/matrix metalloproteinase (MMP) 26-mediated pro-gelatinase B (MMP-9) activation promoted invasion of human prostate carcinoma cells by dissolving basement membrane proteins (Y. G. Zhao et al., J. Biol. Chem., 278: 15056–15064, 2003). Here we report that tissue inhibitor of metalloproteinases (TIMP)-2 and TIMP-4 are potent inhibitors of MMP-26, with apparent Ki values of 1.6 and 0.62 nm, respectively. TIMP-2 and TIMP-4 also inhibited the activation of pro-MMP-9 by MMP-26 in vitro. The expression levels of MMP-26, MMP-9, TIMP-2, and TIMP-4 proteins in DCIS were significantly higher than those in IDC, atypical intraductal hyperplasia, and normal breast epithelia adjacent to DCIS and IDC by immunohistochemistry and integrated morphometry analysis. Double immunofluorescence labeling and confocal laser scanning microscopy revealed that MMP-26 was colocalized with MMP-9, TIMP-2, and TIMP-4 in DCIS cells. Higher levels of MMP-26 mRNA were also detected in DCIS cells by in situ hybridization.
Dickkopf 3 Inhibits Invasion and Motility of Saos-2 Osteosarcoma Cells by Modulating the Wnt-β-Catenin Pathway
Authors: Hoang Bang H. , Kubo Tadahiko , Healey John H. , Yang Rui , Nathan Saminathan S. , Kolb E. Anders , Mazza BethAnne , Meyers Paul A. , Gorlick Richard
Published: September 2005

Osteosarcoma (OS) is a primary malignancy of bone with a tendency to metastasize early. Despite intensive chemotherapy and surgical resection, ∼30% of patients still develop distant metastasis. Our previous work using clinical OS samples suggested that expression of the Wnt receptor LRP5 might be associated with tumor metastasis. In the present study, we used a Dickkopf (Dkk) family member and a dominant-negative LRP5 receptor construct to modulate Wnt signaling in OS cells. Saos-2 cells, which ectopically express Dkk-3, do not undergo apoptosis and exhibit enhanced resistance to serum starvation and chemotherapy-induced cytotoxicity. Transfection of Dkk-3 and dominant-negative LRP5 into Saos-2 cells significantly reduces invasion capacity and cell motility. This blockade is associated with changes in cell morphology consistent with a less invasive phenotype. In addition, Dkk-3 and dominant-negative LRP5 also induce changes in β-catenin localization consistent with an increase in cell-cell adhesion. Taken together, these results support a possible role for Wnt signaling in the pathobiology and progression of human OS.
Myc-Transformed Epithelial Cells Down-Regulate Clusterin, Which Inhibits Their Growth
in Vitro
and Carcinogenesis
in Vivo
Authors: Thomas-Tikhonenko Andrei , Viard-Leveugle Isabelle , Dews Michael , Wehrli Philippe , Sevignani Cinzia , Yu Duonan , Ricci Stacey , el-Deiry Wafik , Aronow Bruce , Kaya Gürkan , Saurat Jean-Hilaire , French Lars E.
Published: September 2005

Effective treatment of malignant carcinomas requires identification of proteins regulating epithelial cell proliferation. To this end, we compared gene expression profiles in murine colonocytes and their c-Myc-transformed counterparts, which possess enhanced proliferative potential. A surprisingly short list of deregulated genes included the cDNA for clusterin, an extracellular glycoprotein without a firmly established function. We had previously demonstrated that in organs such as skin, clusterin expression is restricted to differentiating but not proliferating cell layers, suggesting a possible negative role in cell division. Indeed, its transient overexpression in Myc-transduced colonocytes decreased cell accumulation. Furthermore, clusterin was down-regulated in rapidly dividing human keratinocytes infected with a Myc-encoding adenovirus. Its knockdown via antisense RNA in neoplastic epidermoid cells enhanced proliferation. Finally, recombinant human clusterin suppressed, in a dose-dependent manner, DNA replication in keratinocytes and other cells of epithelial origin. Thus, clusterin appears to be an inhibitor of epithelial cell proliferation in vitro. To determine whether it also affects neoplastic growth in vivo, we compared wild-type and clusterin-null mice with respect to their sensitivity to 7, 12-dimethylbenz(a)anthracene /12-Otetradecanoylphorbol-13-acetate (DMBA/TPA)-induced skin carcinogenesis. We observed that the mean number of papillomas/mouse was higher in clusterin-null animals. Moreover, these papillomas did not regress as readily as in wild-type mice and persisted beyond week 35. The rate of progression toward squamous cell carcinoma was not altered, although those developing in clusterin-null mice were on average better differentiated. These data suggest that clusterin not only suppresses epithelial cell proliferation in vitro but also interferes with the promotion stage of skin carcinogenesis.
Overexpression of the Embryonic-Lethal Abnormal Vision-like Protein HuR in Ovarian Carcinoma Is a Prognostic Factor and Is Associated with Increased Cyclooxygenase 2 Expression
Authors: Denkert Carsten , Weichert Wilko , Pest Sören , Koch Ines , Licht Dirk , Köbel Martin , Reles Angela , Sehouli Jalid , Dietel Manfred , Hauptmann Steffen
Published: September 2005

The human embryonic-lethal abnormal vision-like protein HuR is involved in the regulation of mRNA turnover and serves as a shuttling protein between the nucleus and the cytoplasm that stabilizes mRNAs containing adenine- and uridine-rich elements in their 3′ untranslated region. We have shown recently that expression of cyclooxygenase (COX)-2 is related to poor prognosis in ovarian carcinoma. Other studies have shown that the COX-2 mRNA contains an adenine- and uridine-rich element and is stabilized by HuR. In this study, we investigated the expression and cellular distribution of HuR in 83 primary ovarian carcinomas, 16 borderline tumors of the ovary, 3 normal ovaries, and 9 ovarian carcinoma cell lines. Expression of HuR was detected in all cell lines on the mRNA and protein level and showed a predominantly nuclear staining in OVCAR-3 cells by confocal microscopy. In an immunohistochemical evaluation of human ovarian carcinomas, HuR showed a nuclear expression in 81% of tumors. In addition, a cytoplasmic expression of HuR was observed in a subgroup of 45% of ovarian carcinomas. Nuclear as well as cytoplasmic expression of HuR was significantly increased in ovarian carcinomas compared with borderline tumors or normal ovaries. In univariate analysis, a significant association between cytoplasmic HuR expression and increased COX-2 expression (P = 0.025) as well as between histological grade (P = 0.008) and mitotic activity (P = 0.002) was observed, although nuclear expression of HuR was not correlated with COX-2 expression or other clinicopathological parameters. In Kaplan-Meier survival analysis, increased cytoplasmic expression of HuR was a significant prognostic indicator for progression-free survival (P = 0.03) as well as overall survival (P = 0.007). In multivariate analysis using the Cox regression model, cytoplasmic expression of HuR was an independent prognostic parameter for reduced overall survival with a relative risk of 2.62 (95% confidence interval, 1.32–5.19). Our results suggest that there is a dysregulation of cellular distribution of the mRNA stability factor HuR in a subset of invasive ovarian carcinomas. This dysregulation appears to result in an increased expression of COX-2, an increased proliferative rate, and may lead to a reduced survival time. Additional studies are required to analyze the downstream effects of increased cytoplasmic expression of HuR. In addition, it would be interesting to investigate the prognostic role of increased cytoplasmic expression of HuR in prospective studies.
Dependence of Paclitaxel Sensitivity on a Functional Spindle Assembly Checkpoint
Authors: Sudo Tamotsu , Nitta Masayuki , Saya Hideyuki , Ueno Naoto T.
Published: September 2005

Paclitaxel stabilizes microtubules, causing mitotic arrest and activating the spindle assembly checkpoint. We determined whether suppression of the checkpoint genes Mad2 and BubR1 affects paclitaxel resistance and whether overexpression of Mad2 protein in checkpoint-defective cells enhances paclitaxel sensitivity. Suppression of Mad2 and BubR1 in paclitaxel-treated cancer cells abolished checkpoint function, resulting in paclitaxel resistance that correlated with suppression of cyclin-dependent kinase-1 activity. In contrast, overexpression of Mad2 in cells with a checkpoint defect attributable to low Mad2 expression restored checkpoint function, resulting in enhanced paclitaxel sensitivity that correlated with enhanced cyclin-dependent kinase-1 activity. However, overexpression of Mad2 failed to enhance paclitaxel sensitivity via checkpoint activation in Mad2-independent checkpoint-defective and -intact cells. Thus, checkpoint function is required for paclitaxel sensitivity. These findings show that any molecules that could interfere with the spindle assembly checkpoint could generate paclitaxel resistance in any patient.
Kallikrein 4 is a Predominantly Nuclear Protein and Is Overexpressed in Prostate Cancer
Authors: Xi Zhijun , Klokk Tove Irene , Korkmaz Kemal , Kurys Piotr , Elbi Cem , Risberg Bjørn , Danielsen Håvard , Loda Massimo , Saatcioglu Fahri
Published: September 2005

Kallikreins (KLKs) are highly conserved serine proteases that play key roles in a variety of physiological and pathological processes. KLKs are secreted proteins that have extracellular substrates and function. For example, prostate-specific antigen (or KLK3) is a secreted protein that is widely used as a diagnostic marker for prostate cancer. KLK4 is a recently identified member of the kallikrein family that is regulated by androgens and is highly specific to prostate for expression. Here, we show that the gene product of KLK4, hK4, is the first member of the KLK family that is intracellularly localized. We provide strong evidence that the previously assigned first exon that was predicted to code for a signal peptide that would target hK4 for secretion is not part of the physiologically relevant form of KLK4 mRNA. In addition to detailed mapping of the KLK4 mRNA 5′ end by RT-PCR, this conclusion is supported by predominantly nuclear localization of the hK4 protein in the cell, documented by both immunofluorescence and cell fractionation experiments. Furthermore, in addition to androgens, hK4 expression is regulated by estrogen and progesterone in prostate cancer cells. Finally, in situ hybridization on normal and hyperplastic prostate samples in tissue microarrays indicate that KLK4 is predominantly expressed in the basal cells of the normal prostate gland and overexpressed in prostate cancer. These data suggest that KLK4 has a unique structure and function compared with other members of the KLK family and may have a role in the biology and characterization of prostate cancer.
Pharmacogenomic Identification of Targets for Adjuvant Therapy with the Topoisomerase Poison Camptothecin
Authors: Carson Jonathan P. , Zhang Nianyi , Frampton Garrett M. , Gerry Norman P. , Lenburg Marc E. , Christman Michael F.
Published: September 2005

The response of tumor cells to the unusual form of DNA damage caused by topoisomerase poisons such as camptothecin (CPT) is poorly understood, and knowledge regarding which drugs can be effectively combined with CPT is lacking. To better understand the response of tumor cells to CPT and to identify potential targets for adjuvant therapy, we examined global changes in mRNA abundance in HeLa cells after CPT treatment using Affymetrix U133A GeneChips, which include all annotated human genes (22,283 probe sets). Statistical analysis of the data using a Bayesian/Cyber t test and a modified Benjamini and Hochberg correction for multiple hypotheses testing identified 188 probe sets that are induced and 495 that are repressed 8 h after CPT treatment at a False Discovery Rate of <0.05 and a minimum 3-fold change. This pharmacogenomic approach led us to identify two pathways that are CPT induced: (a) the epidermal growth factor receptor; and (b) nuclear factor-κB-regulated antiapoptotic factors. Experiments using HeLa cells in our lab and prior animal model studies performed elsewhere confirm that inhibitors of these respective pathways super-additively enhance CPT’s cytotoxicity, suggesting their potential as targets for adjuvant therapy with CPT.
Selective Growth Inhibition of Tumor Cells by a Novel Histone Deacetylase Inhibitor, NVP-LAQ824
Authors: Atadja Peter , Gao Lin , Kwon Paul , Trogani Nancy , Walker Heather , Hsu Meier , Yeleswarapu Lakshmi , Chandramouli Nagarajan , Perez Larry , Versace Richard , Wu Arthur , Sambucetti Lidia , Lassota Peter , Cohen Dalia , Bair Kenneth , Wood Alexander , Remiszewski Stacy
Published: September 2005

We have synthesized a histone deacetylase inhibitor, NVP-LAQ824, a cinnamic hydroxamic acid, that inhibited in vitro enzymatic activities and transcriptionally activated the p21 promoter in reporter gene assays. NVP-LAQ824 selectively inhibited growth of cancer cell lines at submicromolar levels after 48–72 h of exposure, whereas higher concentrations and longer exposure times were required to retard the growth of normal dermal human fibroblasts. Flow cytometry studies revealed that both tumor and normal cells arrested in the G2-M phase of the cell cycle after compound treatment. However, an increased sub-G1 population at 48 h (reminiscent of apoptotic cells) was observed only in the cancer cell line. Annexin V staining data supported our hypothesis that NVP-LAQ824 induced apoptosis in tumor and transformed cells but not in normal cells. Western blotting experiments showed an increased histone H3 and H4 acetylation level in NVP-LAQ824-treated cancer cells, suggesting that the likely in vivo target of NVP-LAQ824 was histone deacetylase(s). Finally, NVP-LAQ824 exhibited antitumor effects in a xenograft animal model. Together, our data indicated that the activity of NVP-LAQ824 was consistent with its intended mechanism of action. This novel histone deacetylase inhibitor is currently in clinical trials as an anticancer agent.
Altered Metastatic Behavior of Human Breast Cancer Cells after Experimental Manipulation of Matrix Metalloproteinase 8 Gene Expression
Authors: Montel Valerie , Kleeman Jeanine , Agarwal Dianne , Spinella Dominic , Kawai Kanji , Tarin David
Published: September 2005

Previous work in our laboratory led to the cloning, from the same parent tumor cell line (MDA-MB-435), of two human breast cancer cell lines (M-4A4 and NM-2C5) with opposite metastatic phenotypes. Additional investigations revealed that the nonmetastatic cell line NM-2C5 overexpressed the neutrophil collagenase, matrix metalloproteinase (MMP)-8, relative to its partner. Because other studies have implicated the MMP family in promoting tumor metastasis, we investigated the apparently paradoxical expression of MMP-8 in these cell lines. By genetic engineering, we inverted its relative levels of expression in the two partners and studied the effects on the behavior of the tumors that they generated in athymic mice. Knock-down of expression in NM-2C5 cells by transduction with a sequence encoding a specific ribozyme and overexpression of MMP-8 in M-4A4 cells by retroviral transduction both strikingly changed metastatic performance in opposite directions, indicating that this gene plays a role in the regulation of tumor metastasis.
Quantitative Proteomic Analysis of Proteins Released by Neoplastic Prostate Epithelium
Authors: Martin Daniel B. , Gifford David R. , Wright Michael E. , Keller Andrew , Yi Eugene , Goodlett David R. , Aebersold Reudi , Nelson Peter S.
Published: September 2005

Prostate cancer is unusual among neoplasms in that it may be diagnosed at a curable stage through detection of a protein in serum, the serine protease prostate-specific antigen (PSA). PSA is secreted by both normal and neoplastic prostate epithelial cells in response to androgenic hormones and has found widespread use in cancer screening. Because PSA screening is controversial due to sensitivity and specificity issues, efforts continue to focus on the identification and characterization of additional markers that may be used for diagnostic and therapeutic purposes. In this study, we report the application of quantitative proteomic techniques that incorporate isotope coded affinity tag reagents and tandem mass spectrometry to comprehensively identify secreted and cell surface proteins from neoplastic prostate epithelium. LNCaP cells, a prostate tumor-derived cell line that secretes PSA in response to androgen exposure, were grown in a low protein-defined media under androgen-stimulated (A+) and -starved (A-) conditions. Proteomic analysis of the media identified in excess of 600 proteins, 524 of which could be quantified. Nine percent of the proteins had A+/A- ratios > 2.0, including PSA, and 2.5% had ratios < 0.5. A subset of these androgen-regulated proteins appeared to be expressed in abundance. Of these, selected mass spectrometry observations were confirmed by Western analysis. The findings suggest that androgen-mediated release of proteins may occur through the activation of proteolytic enzymes rather than exclusively through transcriptional or translational control mechanisms. On the basis of their known functional roles, several of the abundant androgen-regulated proteins may participate in the progression of neoplastic epithelial cell growth and should be considered as potential serum markers of neoplastic prostate diseases.
Defucosylated Chimeric Anti-CC Chemokine Receptor 4 IgG1 with Enhanced Antibody-Dependent Cellular Cytotoxicity Shows Potent Therapeutic Activity to T-Cell Leukemia and Lymphoma
Authors: Niwa Rinpei , Shoji-Hosaka Emi , Sakurada Mikiko , Shinkawa Toyohide , Uchida Kazuhisa , Nakamura Kazuyasu , Matsushima Kouji , Ueda Ryuzo , Hanai Nobuo , Shitara Kenya
Published: September 2005

Human IgG1 antibodies with low fucose contents in their asparagine-linked oligosaccharides have been shown recently to exhibit potent antibody-dependent cellular cytotoxicity (ADCC) in vitro. To additionally investigate the efficacy of the human IgG1 with enhanced ADCC, we generated the defucosylated chimeric anti-CC chemokine receptor 4 (CCR4) IgG1 antibody KM2760. KM2760 exhibited much higher ADCC using human peripheral blood mononuclear cells (PBMCs) as effector cells compared with the highly fucosylated, but otherwise identical IgG1, KM3060. In addition, KM2760 also exhibited potent ADCC in the presence of lower concentrations of human PBMCs than KM3060. Because CCR4 is a selective marker of T-cell leukemia/lymphoma, the effectiveness of KM2760 for T-cell malignancy was evaluated in several mouse models. First, to compare the antitumor activity of KM2760 and KM3060, we constructed a human PBMC-engrafted mouse model to determine ADCC efficacy with human effector cells. In this model, KM2760 showed significantly higher antitumor efficacy than KM3060, indicating that KM2760 retains its high potency in vivo. Second, KM2760 suppressed tumor growth in both syngeneic and xenograft mouse models in which human PBMCs were not engrafted. Although murine effector cells exhibited marginal ADCC mediated by KM2760 and KM3060, KM2760 unexpectedly showed higher efficacy than KM3060 in a syngeneic mouse model, suggesting that KM2760 functions in murine effector system in vivo via an unknown mechanism that differs from that in human. These results indicate that defucosylated antibodies with enhanced ADCC as well as potent antitumor activity in vivo are promising candidates for the novel antibody-based therapy.
Differential Repair of the Two Major UV-Induced Photolesions in Trichothiodystrophy Fibroblasts
Authors: Riou Lydia , Eveno Eric , van Hoffen Anneke , van Zeeland Albert A. , Sarasin Alain , Mullenders Leon H. F.
Published: September 2005

Defects in nucleotide excision repair have been shown to be associated with the photosensitive form of the disorder trichothiodystrophy (TTD). Most repair-deficient TTD patients are mutated in the XPD gene, a subunit of the transcription factor TFIIH. Knowledge of the kinetics and efficiency of repair of the two major UV-induced photolesions in TTD is critical to understand the role of unrepaired lesions in the process of carcinogenesis and explain the absence of enhanced skin cancer incidence in TTD patients contrarily to the xeroderma pigmentosum D patients. In this study, we used different approaches to quantify repair of UV-induced cyclobutane pyrimidine dimers (CPD) and pyrimidine (6–4) pyrimidone photoproducts (6–4PP) at the gene and the genome overall level. In cells of two TTD patients, repair of CPD and 6–4PP was reduced compared with normal human cells, but the reduction was more severe in confluent cells than in exponentially growing cells. Moreover, the impairment of repair was more drastic for CPD than 6–4PP. Most notably, exponentially growing TTD cells displayed complete repair 6–4PP over a broad dose range, albeit at a reduced rate compared with normal cells. Strand-specific analysis of CPD repair in a transcriptional active gene revealed that TTD cells were capable to perform transcription-coupled repair. Taken together, the data suggest that efficient repair of 6–4PP in dividing TTD cells in concert with transcription-coupled repair might account for the absence of increased skin carcinogenesis in TTD patients.
Potent Antitumor Activity of Interleukin-27
Authors: Hisada Masayuki , Kamiya Sadahiro , Fujita Koji , Belladonna Maria Laura , Aoki Tatuya , Koyanagi Yasuhisa , Mizuguchi Junichiro , Yoshimoto Takayuki
Published: September 2005

Although much promising data that interleukin (IL)-12 could be a powerful therapeutic agent against cancer were reported in animal models, its excessive toxicity has become a problem for its clinical application. IL-27 is a novel IL-12 family member that plays a role in the early regulation of T helper cell 1 initiation, including induction of T-bet and IL-12 receptor β2 expression. In the present study, we have evaluated the antitumor activity of IL-27 against a murine tumor model of colon carcinoma C26. C26 cells, which were transduced with the single-chain IL-27 cDNA and became secreting IL-27 (C26-IL-27), exhibited minimal tumor growth in vivo, and all of the mice inoculated with these cells survived healthily with complete tumor remission. Inoculation of mice with C26-IL-27 induced enhanced IFN-γ production and cytotoxic T-lymphocyte activity against C26 tumor in spleen cells. Recovered mice from the inoculation showed a tumor-specific protective immunity to the following challenge with parental C26 tumor. The antitumor activity of IL-27 was almost diminished in nude mice, and depletion of CD8+ T cells and neutralization of IFN-γ in immunocompetent mice reduced greatly the antitumor activity. Moreover, the antitumor activity was abolished in T-bet-deficient mice, whereas it was observed unexpectedly in mice deficient of signal transducer and activator of transcription (STAT) 4. These results suggest that IL-27 has potent abilities to induce tumor-specific antitumor activity and protective immunity and that the antitumor activity is mediated mainly through CD8+ T cells, IFN-γ, and T-bet but not through STAT4.
A Pivotal Role of Cyclic AMP-Responsive Element Binding Protein in Tumor Progression
Authors: Abramovitch Rinat , Tavor Einat , Jacob-Hirsch Jasmine , Zeira Evelyne , Amariglio Ninette , Pappo Orit , Rechavi Gideon , Galun Eithan , Honigman Alik
Published: September 2005

Tumor microenvironment controls the selection of malignant cells capable of surviving in stressful and hypoxic conditions. The transcription factor, cyclic AMP-responsive element binding (CREB) protein, activated by multiple extracellular signals, modulates cellular response by regulating the expression of a multitude of genes. Previously, we have demonstrated that two cystein residues, at the DNA binding domain of CREB, mediate activation of CREB-dependent gene expression at normoxia and hypoxia. The construction of a dominant-positive CREB mutant, insensitive to hypoxia cue (substitution of two cystein residues at position 300 and 310 with serine in the DNA binding domain) and of a dominant negative CREB mutant (addition of a mutation in serine133), enabled a direct assessment, in vitro and in vivo, of the role of CREB in tumor progression. In this work, we demonstrate both in vitro and in vivo that CREB controls hepatocellular carcinoma growth, supports angiogenesis, and renders resistance to apoptosis. Along with the identification, by DNA microarray, of the CREB-regulated genes in normoxia and hypoxia, this work demonstrates for the first time that in parallel to other hypoxia responsive mechanisms, CREB plays an important role in hepatocellular carcinoma tumor progression.
Glycine-Extended Gastrin Promotes the Growth of Lung Cancer
Authors: Koh Theodore J. , Field John K. , Varro Andrea , Liloglou Triantafillos , Fielding Pat , Cui Guanglin , Houghton JeanMarie , Dockray Graham J. , Wang Timothy C.
Published: September 2005

The less processed forms of gastrin have recently been shown to act as trophic factors for both normal and malignant colonic cells. Although incompletely processed forms of gastrin such as glycine-extended gastrin and progastrin are also expressed in human lung cancers, the clinical significance of this expression has not been addressed. Consequently, we investigated the effects of overexpression of glycine-extended gastrin in a mouse strain that is prone to developing lung cancer and also examined the expression of incompletely processed gastrins in primary human lung cancers. We found that transgenic overexpression of glycine-extended gastrin in FVB/N mice resulted in a significant increase in the prevalence and growth of bronchoalveolar carcinoma. In addition, a substantial subset of human lung cancers was found to express progastrin and/or glycine-extended gastrin. Overexpression of glycine-extended gastrin by human lung cancers was associated with a significantly decreased survival. Taken together, these results suggest that glycine-extended gastrin may play a role in the growth and progression of some human lung cancers.
Hepatocarcinogenesis in Mice with β-Catenin and Ha-Ras Gene Mutations
Authors: Harada Naomoto , Oshima Hiroko , Katoh Masahiro , Tamai Yositaka , Oshima Masanobu , Taketo Makoto M.
Published: September 2005

We have established previously a mouse strain containing a mutant β-catenin allele of which exon 3 was sandwiched by loxP sequences [Catnblox(ex3)]. In this mouse strain, a Wnt-activating β-catenin mutation alone is insufficient for hepatocarcinogenesis, but additional mutations or epigenetic changes may be required. Here we report that hepatocellular carcinoma develops at the 100% incidence in mice with simultaneous mutations in the β-catenin and H-ras genes that are introduced by adenovirus-mediated Cre expression. Although H-ras mutation alone rapidly causes large cell dysplasia in the hepatocytes, these cells show no autonomous growth within 1 week after infection of the Cre-adenovirus. However, simultaneous induction of an additional mutation in the β-catenin gene causes a clonal expansion of such dysplastic cells, followed by nodular formation and development of hepatocellular carcinoma. These results indicate that β-catenin mutations play a critical role in hepatocarcinogenesis in cooperation with another oncogene and that these mice provide a convenient model to investigate early steps of hepatocarcinogenesis.
Tumor-Specific Inhibition of Membrane-Bound Complement Regulatory Protein Crry with Bispecific Monoclonal Antibodies Prevents Tumor Outgrowth in a Rat Colorectal Cancer Lung Metastases Model
Authors: Gelderman Kyra A. , Kuppen Peter J. K. , Okada Noriko , Fleuren Gert Jan , Gorter Arko
Published: September 2005

Membrane-bound complement regulatory proteins (mCRP) inhibit complement-mediated tumor cell eradication in vitro and in vivo. Immunotherapy of cancer with monoclonal antibodies (mAbs) that activate complement might be hampered by expression of mCRP on tumor cells. An important strategy to improve mAb immunotherapy can be blocking or overwhelming mCRP at the tumor cells surface in a tumor-specific manner. In our study, we investigated the feasibility of this approach in vivo using bispecific mAbs (bi-mAbs). This study, performed in a syngeneic lung metastases model of rat (WAG/Rij) colorectal cancer, showed that modulation of mCRP on tumor cells resulted in significantly decreased tumor outgrowth. Opsonization of tumor cells with a bi-mAb directed against a tumor-associated antigen and rat mCRP Crry (MG42a*5I2) almost completely prevented the outgrowth of lung tumors (0–7 tumors/rat; n = 17). Opsonization with mAb-cobra venom factor conjugates significantly reduced the number of lung tumors (23–59 tumors; n = 12) compared with the unconjugated MG42a (175–246 tumors; n = 17; P = 0.008 and 0.014, respectively). The effect of MG42a*5I2 was shown to be caused by increased complement activation due to inhibition of Crry. Moreover, prophylactic treatment with MG42a*5I2 or MG42a showed comparable results (3–24 and 215–472 tumors, P = 0.02; n = 6) as observed with pre-opsonized tumor cells without noticeable side effects, despite binding of MG42a*5I2 to endothelium and leukocytes. These results demonstrate that Crry inhibits complement-mediated tumor cell eradication by immunotherapeutic mAbs and show that tumor-specific inhibition of complement regulatory proteins using bi-mAbs can significantly improve mAb-mediated immunotherapy.
Cyclooxygenase-2 Is Essential for HER2/
neu
to Suppress
N
- (4-Hydroxyphenyl)retinamide Apoptotic Effects in Breast Cancer Cells
Authors: Simeone Ann-Marie , Li Yu-Jiang , Broemeling Lyle D. , Johnson Marcella M. , Tuna Musaffe , Tari Ana M.
Published: September 2005

We reported that HER2/neu reduces the sensitivity of breast cancer cells to N-(4-hydroxyphenyl)retinamide (4-HPR) by suppressing nitric oxide production. We show that HER2/neu uses Akt to induce cyclooxygenase-2 (COX-2) expression and that inhibition of Akt or COX-2 increases 4-HPR-induced apoptosis and nitric oxide production. Apoptosis induced by the 4-HPR and COX-2 inhibitor combination, although unaffected by an anti-HER2/neu antibody, was reversed by the COX-2 product prostaglandin E2, indicating that COX-2 is a major mechanism by which HER2/neu suppresses 4-HPR apoptosis in breast cancer cells. Combining 4-HPR with COX-2 inhibitors may be a novel chemopreventive strategy against HER2/neu-overexpressing breast tumors.
Identification of Soluble NH2-Terminal Fragment of Glypican-3 as a Serological Marker for Early-Stage Hepatocellular Carcinoma
Authors: Hippo Yoshitaka , Watanabe Kiyotaka , Watanabe Akira , Midorikawa Yutaka , Yamamoto Shogo , Ihara Sigeo , Tokita Susumu , Iwanari Hiroko , Ito Yukio , Nakano Kiyotaka , Nezu Jun-ichi , Tsunoda Hiroyuki , Yoshino Takeshi , Ohizumi Iwao , Tsuchiya Masayuki , Ohnishi Shin , Makuuchi Masatoshi , Hamakubo Takao , Kodama Tatsuhiko , Aburatani Hiroyuki
Published: September 2005

For detection of hepatocellular carcinoma (HCC) in patients with liver cirrhosis, serum α-fetoprotein has been widely used, but its sensitivity has not been satisfactory, especially in small, well-differentiated HCC, and complementary serum marker has been clinically required. Glypican-3 (GPC3), a heparan sulfate proteoglycan anchored to the plasma membrane, is a good candidate marker of HCC because it is an oncofetal protein overexpressed in HCC at both the mRNA and protein levels. In this study, we demonstrated that its NH2-terminal portion [soluble GPC3 (sGPC3)] is cleaved between Arg358 and Ser359 of GPC3 and that sGPC3 can be specifically detected in the sera of patients with HCC. Serum levels of sGPC3 were 4.84 ± 8.91 ng/ml in HCC, significantly higher than the levels seen in liver cirrhosis (1.09 ± 0.74 ng/ml; P < 0.01) and healthy controls (0.65 ± 0.32 ng/ml; P < 0.001). In well- or moderately-differentiated HCC, sGPC3 was superior to α-fetoprotein in sensitivity, and a combination measurement of both markers improved overall sensitivity from 50% to 72%. These results indicate that sGPC3 is a novel serological marker essential for the early detection of HCC.
Role of Carbonic Anhydrase IX in Human Tumor Cell Growth, Survival, and Invasion
Authors: Robertson Naomi , Potter Christian , Harris Adrian L.
Published: September 2005

Carbonic anhydrase IX (CAIX) is a membrane-associated carbonic anhydrase (CA), strongly induced by hypoxia. CAIX is overexpressed in a variety of tumor types and associated with increased metastasis and poor prognosis. An inhibitor of CAs, acetazolamide has been reported to inhibit invasion. We used RNA interference (RNAi) to examine the function of CAIX in MDA468 and MDA231 breast carcinoma cells, which express high levels of CAIX under hypoxia. Hypoxia-induced CA activity was completely blocked by specific RNAi (P < 0.01). RNAi-treated cells showed growth delay in dense monolayer culture and a 50% reduction in clonogenic survival under hypoxia. In the MDA468 cells, there was no effect of RNAi treatment on invasion. In a cell line that did not induce CAIX under hypoxia, RT112, we found no effect on the ability of cells transfected with CAIX to invade or migrate. Thus, CAIX plays an important role in the growth and survival of tumor cells under normoxia and hypoxia, making it a potential target for cancer therapy, but is not involved in invasion.
Systemic Retinoic Acid Treatment Induces Sodium/Iodide Symporter Expression and Radioiodide Uptake in Mouse Breast Cancer Models
Authors: Kogai Takahiko , Kanamoto Yoko , Che Lisa H. , Taki Katsumi , Moatamed Farhad , Schultz James J. , Brent Gregory A.
Published: September 2005

Lactating breast tissue and some breast cancers express the sodium/iodide symporter (NIS) and concentrate iodide. We recently demonstrated that all-trans retinoic acid (tRA) induces both NIS gene expression and iodide accumulation in vitro in well-differentiated human breast cancer cells (MCF-7). In the present study, we investigated the in vivo efficacy and specificity of tRA-stimulated iodide accumulation in mouse breast cancer models. Immunodeficient mice with MCF-7 xenograft tumors were treated with systemic tRA for 5 days. Iodide accumulation in the xenograft tumors was markedly increased, ∼15-fold greater than levels without treatment, and the effects were tRA dose dependent. Iodide accumulation in other organs was not significantly influenced by tRA treatment. Significant induction of NIS mRNA and protein in the xenograft tumors was observed after tRA treatment. Iodide accumulation and NIS mRNA expression were also selectively induced in breast cancer tissues in transgenic mice expressing the oncogene, polyoma virus middle T antigen. These data demonstrate selective induction of functional NIS in breast cancer by tRA. Treatment with short-term systemic retinoic acid, followed by radioiodide administration, is a potential tool in the diagnosis and treatment of some differentiated breast cancer.
Clustering of Minimal Deleted Regions Reveals Distinct Genetic Pathways of Human Hepatocellular Carcinoma
Authors: Jou Yuh-Shan , Lee Chih-Shia , Chang Ya-Hui , Hsiao Chin-Fu , Chen Chian-Feng , Chao Chuan-Chuan , Wu Lawrence S.H. , Yeh Shiou-Hwei , Chen Ding-Shinn , Chen Pei-Jer
Published: September 2005

Systematic scan and statistical analysis of loss of heterozygosity (LOH) has been widely used to define chromosomal aberrations in various cancers for cloning of tumor suppressor genes and for development of prognostic markers. However, the establishment of novel strategies is needed, so that the nonrandom but heterogeneous chromosomal aberration data could provide significant insights into our understanding of molecular pathogenesis of cancers. After comprehensive allelotyping of recurrent allelic losses with 441 highly informative microsatellite markers and overlapping LOH regions on human hepatocellular carcinoma (HCC) chromosomes, 33 minimal deleted regions (MDRs) were revealed. Five and 15 of the 33 MDRs have physical intervals in less than 5 and 10 Mb, respectively, with the smallest MDR9p1 of 2.2 Mb located at 9p21.3-p21.2. Statistical and Kaplan-Meier survival analysis revealed a significant association between the loss of MDR15q1 (15q21.1-q22.2) and the HCC patient survival (adjusted P = 0.033). After cluster analysis of 33 MDRs that represented LOH profiles of each HCC tissue based on clinicopathological features and p53 mutations, two major genetic pathways, low-stage and advanced-stage HCC, were uncovered based on high concordance of MDR clusters. We propose that the definition of genome-wide MDRs on the cancer genome not only narrows down the location of existing tumor suppressor genes to facilitate positional candidate cloning and develop potential prognostic markers after statistical association of MDRs with clinicopathological features but also dissects genetic interactions and pathways of chromosomal aberrations in tumorigenesis.
Differential Response of Human Ovarian Cancer Cells to Induction of Apoptosis by Vitamin E Succinate and Vitamin E Analogue, α-TEA
Authors: Anderson Kristen , Simmons-Menchaca Marla , Lawson Karla A. , Atkinson Jeffrey , Sanders Bob G. , Kline Kimberly
Published: September 2005

A vitamin E derivative, vitamin E succinate (VES; RRR-α-tocopheryl succinate), and a vitamin E analogue, 2,5,7,8-tetramethyl-2R-(4R,8R,12-trimethyltridecyl)chroman-6-yloxy acetic acid (α-TEA), induce human breast, prostate, colon, lung, cervical, and endometrial tumor cells in culture to undergo apoptosis but not normal human mammary epithelial cells, immortalized, nontumorigenic breast cells, or normal human prostate epithelial cells. Human ovarian and cervical cancer cell lines are exceptions, with α-TEA exhibiting greater proapoptotic effects. Although both VES and α-TEA can induce A2780 and subline A2780/cp70 ovarian cancer cells to undergo DNA synthesis arrest within 24 h of treatment, only α-TEA is an effective inducer of apoptosis. VES or α-TEA treatment of cp70 cells with 5, 10, or 20 μg/ml for 3 days induced 5, 6, and 19% versus 9, 36, and 71% apoptosis, respectively. Colony formation data provide additional evidence that cp70 cells are more sensitive to growth inhibition by α-TEA than VES. Differences in stability of the ester-linked succinate moiety of VES versus the ether-linked acetic acid moiety of α-TEA were demonstrated by high-performance liquid chromatography analyses that showed α-TEA to remain intact, whereas VES was hydrolyzed to the free phenol, RRR-α-tocopherol. Pretreatment of cp70 cells with bis-(p-nitrophenyl) phosphate, an esterase inhibitor, before VES treatment, resulted in increased levels of intact VES and apoptosis. Taken together, these data show α-TEA to be a potent and stable proapoptotic agent for human ovarian tumor cells and suggest that endogenous ovarian esterases can hydrolyze the succinate moiety of VES, yielding RRR-α-tocopherol, an ineffective apoptotic-inducing agent.
Sigma Receptors and Cancer
Authors: Aydar Ebru , Palmer Christopher P. , Djamgoz Mustafa B. A.
Published: September 2005

The sigma (σ) receptor and its agonists have been implicated in a myriad of cellular functions, biological processes and diseases. Whereas the precise molecular mechanism(s) of σ receptors and their involvement in cancer cell biology have not been elucidated, recent work has started to shed some light on these issues. A molecular model has been proposed for the cloned σ1 receptor; the precise molecular nature of the σ2 receptor remains unknown. σ receptors have been found to be frequently up-regulated in human cancer cells and tissues. σ2 receptor drugs particularly have been shown to have antiproliferative effects. An interesting possibility is that σ and/or σ1 drugs could produce anticancerous effects by modulating ion channels. As well as proliferation, a variety of other metastatic cellular behaviors such as adhesion, motility, and secretion may also be affected. Other mechanisms of σ receptor action may involve interaction with ankyrin and modulation of intracellular Ca2+ and sphingolipid levels. Although more research is needed to further define the molecular physiology of σ receptors, their involvement in the cellular pathophysiology of cancer raises the possibility that σ drugs could be useful as novel therapeutic agents.