bluuebunny/crossref_metadata_2025 huggingface dataset:
Defective DNA Strand Break Repair after DNA Damage in Prostate Cancer Cells
Authors: Fan Rong , Kumaravel Tirukalikundram S. , Jalali Farid , Marrano Paula , Squire Jeremy A. , Bristow Robert G.
Published: September 2005

Together with cell cycle checkpoint control, DNA repair plays a pivotal role in protecting the genome from endogenous and exogenous DNA damage. Although increased genetic instability has been associated with prostate cancer progression, the relative role of DNA double-strand break repair in malignant versus normal prostate epithelial cells is not known. In this study, we determined the RNA and protein expression of a series of DNA double-strand break repair genes in both normal (PrEC-epithelial and PrSC-stromal) and malignant (LNCaP, DU-145, and PC-3) prostate cultures. Expression of genes downstream of ATM after ionizing radiation-induced DNA damage reflected the p53 status of the cell lines. In the malignant prostate cell lines, mRNA and protein levels of the Rad51, Xrcc3, Rad52, and Rad54 genes involved in homologous recombination were elevated ∼2- to 5-fold in comparison to normal PrEC cells. The XRCC1, DNA polymerase-β and -δ proteins were also elevated. There were no consistent differences in gene expression relating to the nonhomologous end-joining pathway. Despite increased expression of DNA repair genes, malignant prostate cancer cells had defective repair of DNA breaks, alkali-labile sites, and oxidative base damage. Furthermore, after ionizing radiation and mitomycin C treatment, chromosomal aberration assays confirmed that malignant prostate cells had defective DNA repair. This discordance between expression and function of DNA repair genes in malignant prostate cancer cells supports the hypothesis that prostate tumor progression may reflect aberrant DNA repair. Our findings support the development of novel treatment strategies designed to reinstate normal DNA repair in prostate cancer cells.
Selective Loss of AKR1C1 and AKR1C2 in Breast Cancer and Their Potential Effect on Progesterone Signaling
Authors: Ji Qing , Aoyama Chisa , Nien Yih-Dar , Liu Paul I. , Chen Peter K. , Chang Lilly , Stanczyk Frank Z. , Stolz Andrew
Published: September 2005

Progesterone plays an essential role in breast development and cancer formation. The local metabolism of progesterone may limit its interactions with the progesterone receptor (PR) and thereby act as a prereceptor regulator. Selective loss of AKR1C1, which encodes a 20α-hydroxysteroid dehydrogenase [20α-HSD (EC 1.1.1.149)], and AKR1C2, which encodes a 3α-hydroxysteroid dehydrogenase [3α-HSD (EC 1.1.1.52)], was found in 24 paired breast cancer samples as compared with paired normal tissues from the same individuals. In contrast, AKR1C3, which shares 84% sequence identity, and 5α-reductase type I (SRD5A1) were minimally affected. Breast cancer cell lines T-47D and MCF-7 also expressed reduced AKR1C1, whereas the breast epithelial cell line MCF-10A expressed AKR1C1 at levels comparable with those of normal breast tissues. Immunohistochemical staining confirmed loss of AKR1C1 expression in breast tumors. AKR1C3 and AKR1C1 were localized on the same myoepithelial and luminal epithelial cell layers. Suppression of ARK1C1 and AKR1C2 by selective small interfering RNAs inhibited production of 20α-dihydroprogesterone and was associated with increased progesterone in MCF-10A cells. Suppression of AKR1C1 alone or with AKR1C2 in T-47D cells led to decreased growth in the presence of progesterone. Overexpression of AKR1C1 and, to a lesser extent, AKR1C2 (but not AKR1C3) decreased progesterone-dependent PR activation of a mouse mammary tumor virus promoter in both prostate (PC-3) and breast (T-47D) cancer cell lines. We speculate that loss of AKR1C1 and AKR1C2 in breast cancer results in decreased progesterone catabolism, which, in combination with increased PR expression, may augment progesterone signaling by its nuclear receptors.
Phosphatidylinositol 3′-Kinase Activation Leads to Multidrug Resistance Protein-1 Expression and Subsequent Chemoresistance in Advanced Prostate Cancer Cells
Authors: Lee John T. , Steelman Linda S. , McCubrey James A.
Published: September 2005

The development of androgen-independent growth in advanced carcinoma of the prostate (CaP) is associated with poor prognosis and few therapeutic options. Chemotherapeutic drugs offer the afflicted patient palliative benefits, but these are short-lived because of the chemoresistant nature of hormone-refractory prostate cancer. Given the high percentage of CaP patients with mutations in the PTEN tumor suppressor gene, we sought to determine the involvement of the phosphatidylinositol 3′-kinase (PI3K) cascade in the development of CaP drug resistance. PTEN-negative PC3 cells were observed to have increased resistance to both doxorubicin and paclitaxel when compared with PTEN-positive DU145 cells. Furthermore, modulation of PI3K activity with the use of constitutively active and dominant-negative inhibitors was found to affect the ability to CaP cells to respond to chemotoxic treatments. Additionally, inhibition of PI3K with a small molecular weight inhibitor (LY294002) was able to potentiate the antineoplastic activity of both doxorubicin and paclitaxel in CaP cells. Interestingly, multidrug resistance protein-1 (MRP-1) expression, but not MDR-1 (p-glycoprotein), was observed to be induced as a consequence of PI3K activation in these cell types. Inhibition of MRP-1 expression via siRNA was observed to synergistically sensitize CaP cells to chemotoxic drugs while having no appreciable effect on cell growth in the absence of these compounds. Taken together, these data suggest that PI3K activation can lead to the development of chemoresistant cells in prostatic carcinomas through the up-regulation of MRP-1. Thus, inhibition of PI3K activity with concomitant administration of chemotoxic compounds may prove beneficial in preventing the development of drug resistance in patients with hormone-refractory prostate cancer.
Development of Gastric Carcinoma from Intestinal Metaplasia in Cdx2-transgenic Mice
Authors: Mutoh Hiroyuki , Sakurai Shinji , Satoh Kiichi , Tamada Kiichi , Kita Hiroto , Osawa Hiroyuki , Tomiyama Takeshi , Sato Yukihiro , Yamamoto Hironori , Isoda Norio , Yoshida Toru , Ido Kenichi , Sugano Kentaro
Published: September 2005

In the progression of chronic gastritis, gastric mucosal cells deviate from the normal pathway of gastric differentiation to an intestinal phenotype. Many epidemiologic studies have found an association between the formation of intestinal metaplasia and the development of gastric carcinoma. However, there is no direct evidence that shows intestinal metaplasia is a precursor lesion of gastric carcinoma, to date. We periodically examined the intestinal metaplastic mucosa of Cdx2-transgenic mice we have previously generated. Gastric polyps developed from intestinal metaplastic mucosa in all stomachs of Cdx2-transgenic mice examined. These gastric polyps consisted of intestinal-type adenocarcinoma that invaded the submucosa and muscularis propria and occasionally spread into the subserosa. p53 and APC gene mutations were recognized in the adenocarcinomas. The participation of APC and p53 gene mutations in gastric carcinogenesis from the intestinal metaplasia was verified by the Cdx2-transgenic mice, carrying ApcMin mutation or p53 deficiency, that developed gastric polyps much earlier than Cdx2 alone. We successfully showed that long-term intestinal metaplasia induces invasive gastric carcinoma. These results indicate that intestinal metaplasia itself plays a significant role in the genesis and progression of gastric carcinoma.
RNA Interference Targeting Transforming Growth Factor-β Enhances NKG2D-Mediated Antiglioma Immune Response, Inhibits Glioma Cell Migration and Invasiveness, and Abrogates TumorigenicityIn vivo
Authors: Friese Manuel A. , Wischhusen Jörg , Wick Wolfgang , Weiler Markus , Eisele Günter , Steinle Alexander , Weller Michael
Published: September 2005

Transforming growth factor (TGF)-β is the key molecule implicated in impaired immune function in human patients with malignant gliomas. Here we report that patients with glioblastoma, the most common and lethal type of human glioma, show decreased expression of the activating immunoreceptor NKG2D in CD8+ T and natural killer (NK) cells. TGF-β is responsible for the down-regulation of NKG2D expression in CD8+ T and NK cells mediated by serum and cerebrospinal fluid of glioma patients in vitro. Moreover, TGF-β inhibits the transcription of the NKG2D ligand MICA. Interference with the synthesis of TGF-β1 and TGF-β2 by small interfering RNA technology prevents the down-regulation of NKG2D on immune cells mediated by LNT-229 glioma cell supernatant and strongly enhances MICA expression in the glioma cells and promotes their recognition and lysis by CD8+ T and NK cells. Furthermore, TGF-β silencing results in a less migratory and invasive glioma cell phenotype in vitro. LNT-229 glioma cells deficient in TGF-β exhibit a loss of subcutaneous and orthotopic tumorigenicity in nude mice, and NK cells isolated from these mice show an activated phenotype. RNA interference targeting TGF-β1,2 results in a glioma cell phenotype that is more sensitive to immune cell lysis and less motile in vitro and nontumorigenic in nude mice, strongly confirming TGF-β antagonism as a major therapeutic strategy for the future treatment of malignant gliomas.
Proteolytic Enzymes and Altered Glycosylation Modulate Dystroglycan Function in Carcinoma Cells
Authors: Singh Jarnail , Itahana Yoko , Knight-Krajewski Selena , Kanagawa Motoi , Campbell Kevin P. , Bissell Mina J. , Muschler John
Published: September 2005

Alterations in the basement membrane receptor dystroglycan (DG) are evident in muscular dystrophies and carcinoma cells and characterized by a selective loss or modification of the extracellular α-DG subunit. Defects in posttranslational modifications of DG have been identified in some muscular dystrophies, but the underlying modifications in carcinoma cells have not yet been defined. We reveal here multiple posttranslational modifications that modulate the composition and function of DG in normal epithelial cells and carcinoma cells. We show that α-DG is shed from the cell surface of normal and tumorigenic epithelial cells through a proteolytic mechanism that does not require direct cleavage of either α- or β-DG. Shedding is dependent on metalloprotease activity and the proprotein convertase furin. Surprisingly, furin is also found to directly process α-DG as a proprotein substrate, changing the existing model of DG composition. We also show that the glycosylation of α-DG is altered in invasive carcinoma cells, and this modification causes complete loss of laminin binding properties. Together, these data elucidate several novel events regulating the functional composition of DG and reveal defects that arise during cancer progression, providing direction for efforts to restore this link with the basement membrane in carcinoma cells.
Apoptosis Protease Activator Protein-1 Expression Is Dispensable for Response of Human Melanoma Cells to Distinct Proapoptotic Agents
Authors: Zanon Marina , Piris Adriano , Bersani Ilaria , Vegetti Claudia , Molla Alessandra , Scarito Alessia , Anichini Andrea
Published: September 2005

Loss of expression of the apoptosis protease activator protein-1 (APAF-1) in human melanoma is thought to promote resistance to programmed cell death by preventing caspase-9 activation. However, the role of the APAF-1–dependent pathway in apoptosis activated by cellular stress and/or DNA damage has been recently questioned. We investigated APAF-1 expression in a large panel of human melanomas and assessed cellular response to several proapoptotic agents in tumors expressing or lacking APAF-1 protein. In two melanomas with wild-type p53 but with differential expression of APAF-1, treatment with camptothecin, celecoxib, or an nitric oxide synthase inhibitor (1400W) significantly modulated expression of 36 of 96 genes in an apoptosis-specific cDNA macroarray, but APAF-1 mRNA levels were not induced (in APAF-1− cells) nor up-regulated (in APAF-1+ cells), a finding confirmed at the protein level. Treatment with cisplatin, camptothecin, etoposide, betulinic acid, celecoxib, 1400W, and staurosporine promoted enzymatic activity not only of caspases -2, -8, and -3 but also of caspase-9 in both APAF-1+ and APAF-1− tumor cells. Moreover, drug-induced caspase-9 enzymatic activity could be not only partially but significantly reduced by caspase-2, -3, and -8 –specific inhibitors in both APAF-1+ and APAF-1− tumor cells. In response to 1 to 100 μmol/L of cisplatin, camptothecin, or celecoxib, APAF-1+ melanomas (n = 12) did not show significantly increased levels of apoptosis compared with APAF-1− tumors (n = 7), with the exception of enhanced apoptosis in response to a very high dose (100 μmol/L) of etoposide. These results suggest that the response of human melanoma cells to different proapoptotic agents may be independent of their APAF-1 phenotype.
Pancreatic Insulinomas in Multiple Endocrine Neoplasia, Type I Knockout Mice Can Develop in the Absence of Chromosome Instability or Microsatellite Instability
Authors: Scacheri Peter C. , Kennedy Alyssa L. , Chin Koei , Miller Meghan T. , Hodgson J. Graeme , Gray Joe W. , Marx Stephen J. , Spiegel Allen M. , Collins Francis S.
Published: September 2005

Multiple endocrine neoplasia, type I (MEN1) is an inherited cancer syndrome characterized by tumors arising primarily in endocrine tissues. The responsible gene acts as a tumor suppressor, and tumors in affected heterozygous individuals occur after inactivation of the wild-type allele. Previous studies have shown that Men1 knockout mice develop multiple pancreatic insulinomas, but this occurs many months after loss of both copies of the Men1 gene. These studies imply that loss of Men1 is not alone sufficient for tumor formation and that additional somatic genetic changes are most likely essential for tumorigenesis. The usual expectation is that such mutations would arise either by a chromosomal instability or microsatellite instability mechanism. In a study of more then a dozen such tumors, using the techniques of array-based comparative genomic hybridization, fluorescent in situ hybridization, loss of heterozygosity analysis using multiple microsatellite markers across the genome, and real time PCR to assess DNA copy number, it appears that many of these full-blown clonal adenomas remain remarkably euploid. Furthermore, the loss of the wild-type Men1 allele in heterozygous Men1 mice occurs by loss and reduplication of the entire mutant-bearing chromosome. Thus, the somatic genetic changes that are postulated to lead to tumorigenesis in a mouse model of MEN1 must be unusually subtle, occurring at either the nucleotide level or through epigenetic mechanisms.
SPRY2 Is an Inhibitor of the Ras/Extracellular Signal-Regulated Kinase Pathway in Melanocytes and Melanoma Cells with Wild-Type
BRAF
but Not with the V599E Mutant
Authors: Tsavachidou Dimitra , Coleman Mathew L. , Athanasiadis Galene , Li Shuixing , Licht Jonathan D. , Olson Michael F. , Weber Barbara L.
Published: September 2005

BRAF mutations result in constitutively active BRAF kinase activity and increased extracellular signal-regulated kinase (ERK) signaling and cell proliferation. Initial studies have shown that BRAF mutations occur at a high frequency in melanocytic nevi and metastatic lesions, but recent data have revealed much lower incidence of these mutations in early-stage melanoma, implying that other factors may contribute to melanoma pathogenesis in a wild-type (WT) BRAF context. To identify such contributing factors, we used microarray gene expression profiling to screen for differences in gene expression between a panel of melanocytic and melanoma cell lines with WT BRAF and a group of melanoma cell lines with the V599E BRAF mutation. We found that SPRY2, an inhibitor homologous to SPRY4, which was previously shown to suppress Ras/ERK signaling via direct binding to Raf-1, had reduced expression in WT BRAF cells. Using small interfering RNA-mediated SPRY2 knockdown, we showed that SPRY2 acts as an inhibitor of ERK signaling in melanocytes and WT BRAF melanoma cells, but not in cell lines with the V599E mutation. We also show that SPRY2 and SPRY4 directly bind WT BRAF but not the V599E and other exon 15 BRAF mutants. These data suggest that SPRY2, an inhibitor of ERK signaling, may be bypassed in melanoma cells either by down-regulation of its expression in WT BRAF cells, or by the presence of the BRAF mutation.
H2-EaDeficiency Is a Risk Factor for Bleomycin-Induced Lung Fibrosis in Mice
Authors: Du Min , Irani Roxanna A. , Stivers David N. , Lee Sang-Joon , Travis Elizabeth L.
Published: September 2005

Pulmonary fibrosis is a significant complication in cancer patients when treated by radiation, e.g., thoracic malignant diseases, or chemotherapeutic agents. Bleomycin is one of the primary drugs used to treat testicular cancer, but the incidence of significant pulmonary fibrosis limits the dose. It is known that susceptibility to bleomycin-induced pulmonary fibrosis is a heritable trait controlled by multiple genes, none of which, however, are yet known. In this study, we used expression profiling and genetic analysis in mouse models of bleomycin-induced pulmonary fibrosis and identified MHC class II antigen Eα (H2-Ea) as a risk factor for this disease. We found that a loss-of-function deletion in the H2-Ea gene was linked to susceptibility. A functional test of H2-Ea in transgenic mice showed 100% survival in the transgenic mice compared with 53% in C57BL/10J mice and significantly decreased pulmonary fibrosis from 16.42% (C57BL/10J) to 5.76% (transgenic; P = 1.20e−8). These results show that H2-Ea expression protects mice from bleomycin-induced pulmonary fibrosis, which implicates H2-Ea as a candidate susceptibility gene for pulmonary fibrosis.
Liposome-Encapsulated CpG Oligodeoxynucleotides as a Potent Adjuvant for Inducing Type 1 Innate Immunity
Authors: Suzuki Yoshinori , Wakita Daiko , Chamoto Kenji , Narita Yoshinori , Tsuji Takemasa , Takeshima Tsuguhide , Gyobu Hiroshi , Kawarada You , Kondo Satoshi , Akira Shizuo , Katoh Hiroyuki , Ikeda Hiroaki , Nishimura Takashi
Published: September 2005

Unmethylated cytosine-phosphorothioate-guanine oligodeoxynucleotides (CpG-ODNs) exhibit potent immunostimulating activity by binding with Toll-like receptor 9 (TLR9) expressed on antigen-presenting cells. Here, we show that CpG-ODN encapsulated in cationic liposomes (CpG-liposomes) improves its incorporation into CD11c+ dendritic cells (DCs) and induces enhanced serum interleukin (IL)-12 levels compared with unmodified CpG-ODN. CpG-liposome potently activated natural killer (NK) cells (84.3%) and NKT cells (48.3%) to produce interferon-γ (IFN-γ), whereas the same dose of unmodified CpG-ODN induced only low numbers of IFN-γ–producing NK cells (12.7%) and NKT cells (1.6%) to produce IFN-γ. In contrast with the NKT cell agonist α-galactosylceramide, which induces both IFN-γ and IL-4 production by NKT cells, CpG-liposome only induced IFN-γ production by NKT cells. Such potent adjuvant activities of CpG-liposome were absent in TLR9-deficient mice, indicating that CpG-liposome was as effective as CpG-ODN in stimulating type 1 innate immunity through TLR9. In addition to TLR9, at least two other factors, IL-12 production by DCs and direct contact between DCs and NK or NKT cells, were essential for inducing type 1 innate immunity by CpG-liposome. Furthermore, ligation of TLR9 by CpG-liposome coencapsulated with ovalbumin (OVA) caused the induction of OVA-specific CTLs, which exhibited potent cytotoxicity against OVA-expressing tumor cells. These results indicate that CpG-liposome alone or combined with tumor antigen protein provides a promising approach for the prevention or therapy of tumors.
Reduced Immunoglobulin E and Allergy among Adults with Glioma Compared with Controls
Authors: Wiemels Joseph L. , Wiencke John K. , Patoka Joseph , Moghadassi Michelle , Chew Terri , McMillan Alex , Miike Rei , Barger Geoffrey , Wrensch Margaret
Published: September 2005

We and others have reported previously that adults with glioma are 1.5- to 4-fold less likely than controls to report a variety of allergic conditions. The consistent nature of this relationship calls for a biological explanation so that preventative or therapeutic modalities can be explored. We enrolled 403 newly diagnosed adult glioma cases in the San Francisco Bay Area over a 3-year period using a population-based cancer registry and 402 age/gender/ethnicity frequency-matched controls identified via random digit dialing. We assessed total, food-specific, and respiratory-specific IgE in available case (n = 228) and control (n = 289) serum samples. IgE levels were associated with gender, age, smoking status, and ethnicity among cases and/or controls. Among the cases, IgE levels were not associated with aspects of glioma therapy including radiation, chemotherapy, or tumor resection. Total IgE levels were lower in cases than controls: age/gender/ethnicity/education/smoking-adjusted odds ratio (OR) for elevated versus normal total IgE was 0.37 [95% confidence interval (CI), 0.22–0.64]. For the food panel, OR was 0.12 (95% CI, 0.04–0.41). For the respiratory panel, OR was 0.76 (95% CI, 0.52–1.1). Among respiratory allergies, late age of onset (>12 years) but not IgE levels defined a group with strong associations with risk (OR, 0.50; 95% CI, 0.33–0.75). These results corroborate and strengthen our findings of an inverse association between allergic reactions and glioma by showing a relationship with a biomarker for allergy and cancer for the first time. Furthermore, the results indicate a complex relationship between allergic disease and glioma risk that varies by allergen and allergic pathology.
Bone Marrow Contribution to Tumor-Associated Myofibroblasts and Fibroblasts
Authors: Direkze Natalie C. , Hodivala-Dilke Kairbaan , Jeffery Rosemary , Hunt Toby , Poulsom Richard , Oukrif Dahmane , Alison Malcolm R. , Wright Nicholas A.
Published: September 2005

The role of myofibroblasts in tissue repair and fibrosis is well documented, but the source of these myofibroblasts is unclear. There is evidence of a circulating population of fibrocytes that can home to areas of injury and contribute to myofibroblast populations. Previously, we have shown that the bone marrow is a source of myofibroblasts for many tissues including the gut, lung, and kidney and that this phenomenon is exacerbated by injury. We now show that the bone marrow can contribute to myofibroblast and fibroblast populations in tumor stroma in a mouse model of pancreatic insulinoma. Mice transgenic for the rat insulin promoter II gene linked to the large-T antigen of SV40 (RIPTag) develop solid β-cell tumors of the pancreas. Approximately 25% of myofibroblasts in these pancreatic tumors were donor-derived, and these were concentrated toward the edge of the tumor. Thus, the development of tumor stroma is at least in part a systemic response that may ultimately yield methods of targeting new therapy.
Tumor Cells Fail to
trans
-Induce Telomerase in Human Umbilical Vein Endothelial Cell Cultures
Authors: Pascale Esterina , Reale Graziella Cimino , D’Ambrosio Ettore
Published: September 2005

The shortening of the telomeres that occurs in most somatic cells and untransformed cell cultures is considered a hallmark of cellular senescence. Re-activation of telomerase, which is usually present in immortal cells, avoids telomere shortening and considerably extends the culture life span. Normal human endothelial cells are characterized by an accelerated rate of telomere shortening and reach replicative senescence after a limited number of cell divisions. It has recently been reported that human telomerase reverse transcriptase expression may be strongly up-regulated in human endothelial cells cocultivated with tumor cells. Due to the important implications of this finding on tumor progression, we have extensively analyzed for the presence of telomerase in primary human endothelial cells either cocultivated with tumor cells or grown with tumor-conditioned medium. We found modest, but readily detectable, amounts of telomerase in all human endothelial cell cultures analyzed that disappeared as the cultures approached senescence. Quantitative reverse transcription-PCR also showed a direct correlation between human telomerase reverse transcriptase expression and the proliferative index of the cultures. Nevertheless, we did not find any evidence of induction of telomerase activity by tumor cells in any of the tested conditions. All data indicate that telomerase in human endothelial cells follows an activation program that is strictly associated to the culture growth rate.
The Combination of Genetic Instability and Clonal Expansion Predicts Progression to Esophageal Adenocarcinoma
Authors: Maley Carlo C. , Galipeau Patricia C. , Li Xiaohong , Sanchez Carissa A. , Paulson Thomas G. , Blount Patricia L. , Reid Brian J.
Published: September 2005

There is debate in the literature over the relative importance of genetic instability and clonal expansion during progression to cancer. Barrett’s esophagus is a uniquely suited model to investigate neoplastic progression prospectively because periodic endoscopic biopsy surveillance is recommended for early detection of esophageal adenocarcinoma. We hypothesized that expansion of clones with genetic instability would predict progression to esophageal adenocarcinoma. We measured p16 (CDKN2A/INK4A) lesions (loss of heterozygosity, mutations, and CpG island methylation), p53 (TP53) lesions (loss of heterozygosity, mutation) and ploidy abnormalities (aneuploidy, tetraploidy) within each Barrett’s esophagus segment of a cohort of 267 research participants, who were followed prospectively with cancer as an outcome. We defined the size of a lesion as the fraction of cells with the lesion multiplied by the length of the Barrett’s esophagus segment. A Cox proportional hazards regression indicates that the sizes of clones with p53 loss of heterozygosity (relative risk = 1.27x for an x cm clone; 95% confidence interval, 1.07–1.50) or ploidy abnormalities (relative risk = 1.31x for an x cm clone; 95% confidence interval, 1.07–1.60) predict progression to esophageal adenocarcinoma better than the mere presence of such clones (likelihood ratio test, P < 0.01). Controlling for length of the Barrett’s esophagus segment had little effect. The size of a clone with a p16 lesion is not a significant predictor of esophageal adenocarcinoma when we controlled for p53 loss of heterozygosity status. The combination of clonal expansion and genetic instability is a better predictor of cancer outcome than either alone. This implies that interventions that limit expansion of genetically unstable clones may reduce risk of progression to cancer.
Gene Expression Profiling in Uveal Melanoma Reveals Two Molecular Classes and Predicts Metastatic Death
Authors: Onken Michael D. , Worley Lori A. , Ehlers Justis P. , Harbour J. William
Published: September 2005

Melanomas are notoriously difficult to classify because of a lack of discrete clinical and pathological stages. Here, we show that primary uveal melanomas surprisingly cluster into two distinct molecular classes based on gene expression profile. Genes that discriminate class 1 (low-grade) from class 2 (high-grade) include highly significant clusters of down-regulated genes on chromosome 3 and up-regulated genes on chromosome 8q, which is consistent with previous cytogenetic studies. A three-gene signature allows biopsy-size tumor samples to be assigned accurately to tumor classes using either array or PCR platforms. Most importantly, this molecular classification strongly predicts metastatic death and outperforms other clinical and pathological prognostic indicators. These studies offer new insights into melanoma pathogenesis, and they provide a practical foundation for effective clinical predictive testing.
Human Polynucleotide Phosphorylase (
hPNPase

old-35
)
Authors: Sarkar Devanand , Lebedeva Irina V. , Emdad Luni , Kang Dong-chul , Baldwin Albert S. , Fisher Paul B.
Published: September 2005

Chronic inflammation is a characteristic feature of aging, and the relationship between cellular senescence and inflammation, although extensively studied, is not well understood. An overlapping pathway screen identified human polynucleotide phosphorylase (hPNPaseold-35), an evolutionary conserved 3′,5′-exoribonuclease, as a gene up-regulated during both terminal differentiation and cellular senescence. Enhanced expression of hPNPaseold-35 via a replication-incompetent adenovirus (Ad.hPNPaseold-35) in human melanoma cells and normal human melanocytes results in a characteristic senescence-like phenotype. Reactive oxygen species (ROS) play a key role in the induction of both in vitro and in vivo senescence. We now document that overexpression of hPNPaseold-35 results in increased production of ROS, leading to activation of the nuclear factor (NF)-κB pathway. Ad.hPNPaseold-35 infection promotes degradation of IκBα and nuclear translocation of NF-κB and markedly increases binding of the transcriptional activator p50/p65. The generation of ROS and activation of NF-κB by hPNPaseold-35 are prevented by treatment with a cell-permeable antioxidant, N-acetyl-l-cysteine. Infection with Ad.hPNPaseold-35 enhances the production of interleukin (IL)-6 and IL-8, two classical NF-κB-responsive cytokines, and this induction is inhibited by N-acetyl-l-cysteine. A cytokine array reveals that Ad.hPNPaseold-35 infection specifically induces the expression of proinflammatory cytokines, such as IL-6, IL-8, RANTES, and matrix metalloproteinase (MMP)-3. We hypothesize that hPNPaseold-35 might play a significant role in producing pathological changes associated with aging by generating proinflammatory cytokines via ROS and NF-κB. Understanding the relationship between hPNPaseold-35 and inflammation and aging provides a unique opportunity to mechanistically comprehend and potentially intervene in these physiologically important processes.
Proinvasive Properties of Ovarian Cancer Ascites-Derived Membrane Vesicles
Authors: Graves Laura E. , Ariztia Edgardo V. , Navari Jason R. , Matzel Heather J. , Stack M. Sharon , Fishman David A.
Published: September 2005

Malignant ovarian ascites are rich in cellular components, membrane-bound vesicles, and soluble proteins. This study focused on the structure of membrane-bound vesicles and their ability to promote invasion in cultured malignant ovarian epithelium. Membrane vesicles were derived from women with stage I–IV malignant ovarian ascites and from nonmalignant gynecologic ascites. Isolated vesicles were characterized by immunofluorescence and Western blot analysis. Using gel zymography for matrix metalloproteinase (MMP) detection and a colorimetric assay for urokinase-type plasminogen activator (uPA) analysis, we analyzed the proteinase activities of MMP-2, MMP-9, and uPA from the prepared vesicles, whole cells isolated from ascites, and the cell-free ultracentrifuged supernatant. The invasiveness of established cultured malignant ovarian epithelium on addition of ascites-derived vesicles was tested using a Matrigel-based invasion assay. Fractionation of malignant ascites revealed that extracellular matrix-degrading proteinases including MMPs and uPA are localized preferentially in membrane vesicles. All malignant vesicles tested, regardless of cancer stage, stimulated invasion. Furthermore, the combination of ovarian cancer cells and membrane vesicles resulted in greater uPA activation than that of cells or vesicles alone. Membrane vesicles from malignant ascites were also found to contain activated MMP-2, MMP-9, and uPA. Our data suggest that vesicle-stimulated proteinase activation leads to increased extracellular matrix degradation, which may facilitate tumor cell invasion and metastasis.
A Novel RARβ Isoform Directed by a Distinct Promoter P3 and Mediated by Retinoic Acid in Breast Cancer Cells
Authors: Peng Xinjian , Maruo Takeshi , Cao Yanxia , Punj Vasu , Mehta Rajeshwari , Das Gupta Tapas K. , Christov Konstantin
Published: September 2005

Retinoids regulate gene transcription through activating retinoic acid receptors (RARs)/retinoic X receptors (RXRs). Of the three RAR receptors (α, β, and γ), RARβ has been considered a tumor suppressor gene. Here, we identified a novel RARβ isoform-RARβ5 in breast epithelial cells, which could play a negative role in RARβ signaling. Similar to RARβ2, the first exon (59 bp) of RARβ5 is RARβ5 isoform specific, whereas the other exons are common to all of the RARβ isoforms. The first exon of RARβ5 does not contain any translation start codon, and therefore its protein translation begins at an internal methionine codon of RARβ2, lacking the A, B, and part of C domain of RARβ2. RARβ5 protein was preferentially expressed in estrogen receptor-negative breast cancer cells and normal breast epithelial cells that are relatively resistant to retinoids, whereas estrogen receptor-positive cells that did not express detectable RARβ5 protein were sensitive to retinoid treatment, suggesting that this isoform may affect the cellular response to retinoids. RARβ5 isoform is unique among all of the RARs, because a corresponding isoform was not detectable for either RARα or RARγ. RARβ5 mRNA was variably expressed in normal and cancerous breast epithelial cells. Its transcription was under the control of a distinct promoter P3, which can be activated by all-trans-retinoic acid (atRA) and other RAR/RXR selective retinoids in MCF-7 and T47D breast cancer cells. We mapped the RARβ5 promoter and found a region -302/-99 to be the target region of atRA. In conclusion, we identified and initially characterized RARβ5 in normal, premalignant, and malignant breast epithelial cells. RARβ5 may serve as a potential target of retinoids in prevention and therapy studies.
From Mice to Humans
Authors: Hu Yuhui , Sun Hongxia , Drake Jeffrey , Kittrell Frances , Abba Martin C. , Deng Li , Gaddis Sally , Sahin Aysegul , Baggerly Keith , Medina Daniel , Aldaz C. Marcelo
Published: September 2005

Genetically engineered mouse mammary cancer models have been used over the years as systems to study human breast cancer. However, much controversy exists on the utility of such models as valid equivalents to the human cancer condition. To perform an interspecies gene expression comparative study in breast cancer we used a mouse model that most closely resembles human breast carcinogenesis. This system relies on the transplant of p53 null mouse mammary epithelial cells into the cleared mammary fat pads of syngeneic hosts. Serial analysis of gene expression (SAGE) was used to obtain gene expression profiles of normal and tumor samples from this mouse mammary cancer model (>300,000 mouse mammary-specific tags). The resulting mouse data were compared with 25 of our human breast cancer SAGE libraries (>2.5 million human breast-specific tags). We observed significant similarities in the deregulation of specific genes and gene families when comparing mouse with human breast cancer SAGE data. A total of 72 transcripts were identified as commonly deregulated in both species. We observed a systematic and significant down-regulation in all of the tumors from both species of various cytokines, including CXCL1 (GRO1), LIF, interleukin 6, and CCL2. All of the mouse and most human mammary tumors also displayed decreased expression of genes known to inhibit cell proliferation, including NFKBIA (IKBα), GADD45B, and CDKN1A (p21); transcription-related genes such as CEBP, JUN, JUNB, and ELF1; and apoptosis-related transcripts such as IER3 and GADD34/PPP1R15A. Examples of overexpressed transcripts in tumors from both species include proliferation-related genes such as CCND1, CKS1B, and STMN1 (oncoprotein 18); and genes related to other functions such as SEPW1, SDFR1, DNCI2, and SP110. Importantly, abnormal expression of several of these genes has not been associated previously with breast cancer. The consistency of these observations was validated in independent mouse and human mammary cancer sets.

This is the first interspecies comparison of mammary cancer gene expression profiles. The comparative analysis of mouse and human SAGE mammary cancer data validates this p53 null mouse tumor model as a useful system closely resembling human breast cancer development and progression. More importantly, these studies are allowing us to identify relevant biomarkers of potential use in human studies while leading to a better understanding of specific mechanisms of human breast carcinogenesis.
Caspase-Independent Cell Death by Arsenic Trioxide in Human Cervical Cancer Cells
Authors: Kang Young-Hee , Yi Min-Jung , Kim Min-Jung , Park Moon-Taek , Bae Sangwoo , Kang Chang-Mo , Cho Chul-Koo , Park In-Chul , Park Myung-Jin , Rhee Chang Hun , Hong Seok-Il , Chung Hee Yong , Lee Yun-Sil , Lee Su-Jae
Published: September 2005

Although mechanisms of arsenic trioxide (As2O3)-induced cell death have been studied extensively in hematologic cancers, those in solid cancers have yet to be clearly defined. In this study, we showed that the translocation of apoptosis-inducing factor (AIF) from mitochondria to the nucleus is required for As2O3-induced cell death in human cervical cancer cells. We also showed that reactive oxygen species (ROS)-mediated poly(ADP-ribose) polymerase-1 (PARP-1) activation is necessary for AIF release from mitochondria. The treatment of human cervical cancer cells with As2O3 induces dissipation of mitochondrial membrane potential (Δψm), translocation of AIF from mitochondria to the nucleus, and subsequent cell death. Small interfering RNA targeting of AIF effectively protects cervical cancer cells against As2O3-induced cell death. As2O3 also induces an increase of intracellular ROS level and a marked activation of PARP-1. N-acetyl-l-cystein, a thiol-containing antioxidant, completely blocks As2O3-induced PARP-1 activation, Δψm loss, nuclear translocation of AIF from mitochondria, and the consequent cell death. Furthermore, pretreatment of 1,5-dihydroxyisoquinoline or 3,4-dihydro-5-[4-(1-piperidinyl)butoxy]-1(2H)-isoquinolinone, PARP-1 inhibitors, effectively attenuates the loss of Δψm, AIF release, and cell death. These data support a notion that ROS-mediated PARP-1 activation signals AIF release from mitochondria, resulting in activation of a caspase-independent pathway of cell death in solid tumor cells by As2O3 treatment.
Myeloperoxidase Genotype, Fruit and Vegetable Consumption, and Breast Cancer Risk
Authors: Ahn Jiyoung , Gammon Marilie D. , Santella Regina M. , Gaudet Mia M. , Britton Julie A. , Teitelbaum Susan L. , Terry Mary Beth , Neugut Alfred I. , Josephy P. David , Ambrosone Christine B.
Published: September 2005

Myeloperoxidase (MPO), an antimicrobial enzyme in the breast, generates reactive oxygen species (ROS) endogenously. An MPO G463A polymorphism exists in the promoter region, with the variant A allele conferring lower transcription activity than the common G allele. Because oxidative stress may play a role in breast carcinogenesis, we evaluated MPO genotypes in relation to breast cancer risk among 1,011 cases and 1,067 controls from the Long Island Breast Cancer Study Project (1996–1997). We also assessed the potential modifying effects of dietary antioxidants and hormonally related risk factors on these relationships. Women over 20 years with incident breast cancer who were residents of Nassau and Suffolk Counties, NY, were identified as potential cases. Population-based controls were frequency matched by 5-year age groups. Genotyping was performed with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF) technology, and suspected breast cancer risk factors and usual dietary intake were assessed during an in-person interview. Unconditional logistic regression was used to estimate odds ratios and 95% confidence intervals. Having at least one A allele was associated with an overall 13% reduction in breast cancer risk. When consumption of fruits and vegetables and specific dietary antioxidants were dichotomized at the median, inverse associations with either GA or AA genotypes were most pronounced among women who consumed higher amounts of total fruits and vegetables (odds ratio, 0.75; 95% confidence interval, 0.58–0.97); this association was not noted among the low-consumption group (P for interaction = 0.04). Relationships were strongest among premenopausal women. Results from this first study of MPO genotypes and breast cancer risk indicate that MPO variants, related to reduced generation of ROS, are associated with decreased breast cancer risk, and emphasize the importance of fruit and vegetable consumption in reduction of breast cancer risk.
Proliferation of Transformed Somatotroph Cells Related to Low or Absent Expression of Protein Kinase A Regulatory Subunit 1A Protein
Authors: Lania Andrea G. , Mantovani Giovanna , Ferrero Stefano , Pellegrini Caterina , Bondioni Sara , Peverelli Erika , Braidotti Paola , Locatelli Marco , Zavanone Mario L. , Ferrante Emanuela , Bosari Silvano , Beck-Peccoz Paolo , Spada Anna
Published: September 2005

The two regulatory subunits (R1 and R2) of protein kinase A (PKA) are differentially expressed in cancer cell lines and exert diverse roles in growth control. Recently, mutations of the PKA regulatory subunit 1A gene (PRKAR1A) have been identified in patients with Carney complex. The aim of this study was to evaluate the expression of the PKA regulatory subunits R1A, R2A, and R2B in a series of 30 pituitary adenomas and the effects of subunit activation on cell proliferation. In these tumors, neither mutation of PRKAR1A nor loss of heterozygosity was identified. By real-time PCR, mRNA of the three subunits was detected in all of the tumors, R1A being the most represented in the majority of samples. By contrast, immunohistochemistry documented low or absent R1A levels in all tumors, whereas R2A and R2B were highly expressed, thus resulting in an unbalanced R1/R2 ratio. The low levels of R1A were, at least in part, due to proteasome-mediated degradation. The effect of the R1/R2 ratio on proliferation was assessed in GH3 cells, which showed a similar unbalanced pattern of R subunits expression, and in growth hormone-secreting adenomas. The R2-selective cAMP analog 8-Cl cAMP and R1A RNA silencing, stimulated cell proliferation and increased Cyclin D1 expression, respectively, in human and rat adenomatous somatotrophs. These data show that a low R1/R2 ratio promoted proliferation of transformed somatotrophs and are consistent with the Carney complex model in which R1A inactivating mutations further unbalance this ratio in favor of R2 subunits. These results suggest that low expression of R1A protein may favor cAMP-dependent proliferation of transformed somatotrophs.
Failed Adoptive Immunotherapy with Tumor-Specific T Cells
Authors: Roychowdhury Sameek , May Kenneth F. , Tzou Katherine S. , Lin Teresa , Bhatt Darshna , Freud Aharon G. , Guimond Martin , Ferketich Amy K. , Liu Yang , Caligiuri Michael A.
Published: September 2005

Adoptive immunotherapy with tumor-specific T cells has emerged as a valid approach for prevention or treatment of diseases, such as melanoma and EBV-associated lymphoma. As interleukin (IL) 15 promotes survival of CD8+ memory CTLs, we hypothesized that it could be used to enhance antitumor immunity in vivo through the maintenance of adoptively transferred memory CTL. To test this, we treated mice bearing P1A+ tumors with adoptively transferred T cells possessing a transgenic Vα8+ T-cell receptor specific for the P1A tumor antigen (called P1CTL). Mice were then randomized to receive daily low-dose IL-15 (0.5 μg/day) or PBS. Mice receiving the transgenic P1CTL and IL-15 experienced a significantly delayed tumor relapse or complete tumor regression (P < 0.002 compared with PBS), with a striking persistence of the CD8+ Vα8+ P1CTL compared with mice receiving the CD8+ Vα8+ P1CTL and PBS vehicle (26.3 versus 5.1% P < 10−5). Animals exhibiting complete tumor regression had a significant population of CD8+ Vα8+ P1CTL (46%) that persisted with IL-15 treatment until 140 days after adoptive transfer and successfully defended them against tumor rechallenge without IL-15. Low-dose IL-2 afforded no protection over vehicle and resulted in lower percentages of T cells with an activated memory phenotype, lower Bcl-2 expression, and lower ex vivo antitumor cytotoxicity compared with mice treated with IL-15. Collectively, the data support the notion that exogenous low-dose IL-15 therapy can enhance and even reverse the limited efficacy of adoptively transferred tumor-specific T-cell therapy and may do so in a fashion that is superior and distinct from exogenous IL-2 therapy.
STAT1
Authors: Thomas Michelle , Finnegan Clodagh E. , Rogers Katherine M.-A. , Purcell James W. , Trimble Anne , Johnston Patrick G. , Boland Marion P.
Published: September 2005

The anthracyclines, such as doxorubicin, are widely used in the treatment of breast cancer. Previously, we showed that these drugs could activate the transcription factor, nuclear factor κB, in a DNA damage-dependent manner. We now show that these drugs can potentiate the activation of signal transducer and activator of transcription 1 (STAT1) in MDA-MB 435 breast cancer cells treated with IFN-γ. We observed that key markers of STAT1 activation, including tyrosine 701 and serine 727 phosphorylation, were enhanced in the presence of doxorubicin. This potentiation resulted in enhanced nuclear localization of activated STAT1 and led to an increase in the nuclear binding of activated STAT complexes. The observed potentiation was specific for STAT1 and IFN-γ, as no effects were observed with either STAT3 or STAT5. Furthermore, the type I IFNs (α and β) had little or no effect. The observed effects on STAT1 phosphorylation have previously been linked with maximal transcriptional activation and apoptosis. Cell viability was assessed by crystal violet staining followed by analysis with CalcuSyn to determine combination index values, a measure of synergy. We confirmed that significant synergy existed between IFN-γ and doxorubicin (combination index = 0.34) at doses lower than IC50 values for this drug (0.67 μmol/L). In support of this, we observed that apoptotic cell death was also enhanced by measuring poly(ADP-ribose) polymerase and caspase-3 cleavage. Finally, suppression of STAT1 expression by small-interfering RNA resulted in a loss of synergistic apoptotic cell death compared with cells, where no suppression of STAT1 expression was attained with scrambled small-interfering RNA control. We conclude that doxorubicin potentiates STAT1 activation in response to IFN-γ, and that this combination results in enhanced apoptosis in breast cancer cells.