bluuebunny/crossref_metadata_2025_split huggingface dataset:
Antiproliferative effects of the histone deacetylase inhibitor FR901228 on small‐cell lung cancer lines and drug‐resistant sublines
Authors: Tsurutani Junji , Soda Hiroshi , Oka Mikio , Suenaga Mitsuhiro , Doi Seiji , Nakamura Yoichi , Nakatomi Katsumi , Shiozawa Ken , amada Yasuaki Y , Kamihira Shimeru , Kohno Shigeru 
Published: February 2003

AbstractFR901228 is a novel histone deacetylase (HDAC) inhibitor, and its antiproliferative effects on non‐small cell lung cancer cells have been shown in vitro. However, there have been no reports concerning the effects on small‐cell lung cancer (SCLC). We have recently demonstrated that the HDAC inhibitors trichostatin A and sodium butyrate inhibit expression of the catalytic subunit of telomerase (hTERT) mRNA and telomerase activity in prostate cancer cells. The present study was designed to evaluate the effects of FR901228 on proliferation and telomerase activity in SCLC cells in vitro. FR901228 at 5 to 10 nM increased the fraction of cells in the G2/M and sub‐G1 phases of the cell‐cycle, and inhibited the growth of H69, H526 and H82 cell lines. The expression of hTERT mRNA was inhibited 6 hr after treatment, prior to obvious inhibition of cell growth or cell‐cycle distribution shifts. The inhibition of hTERT mRNA expression and telomerase activity was not a consequence of cell‐growth arrest or apoptosis. Cycloheximide blocked the suppression of hTERT mRNA induced by FR901228, and the inhibition of hTERT mRNA by FR901228 required newly synthesized proteins. FR901228 also effectively inhibited growth of etoposide‐resistant UMCC‐1/VP‐16, irinotecan‐resistant PC‐6/SN2‐5H and cisplatin‐resistant H526/CDDP cells having decreased expression of hTERT mRNA and telomerase activity, as well as their parental cells. This implies that SCLC resistant to these key drugs are not cross‐resistant to FR901228. The present study suggests that FR901228 may be a promising drug for chemotherapy of cancers including SCLC, even for refractory or relapsing tumors after conventional chemotherapy. © 2003 Wiley‐Liss, Inc.
Reactive oxygen species‐mediated regulation of eNOS and iNOS expression in multicellular prostate tumor spheroids
Authors: Wartenberg Maria , Schallenberg Maurice , Hescheler Jürgen , Sauer Heinrich 
Published: February 2003

AbstractNitric oxide (NO) generated by either endothelial nitric oxide synthase (eNOS) or inducible nitric oxide synthase (iNOS) may be involved in prostate tumorigenesis through the inhibition of reactive oxygen species (ROS)‐induced apoptosis. Multicellular DU‐145 prostate tumor spheroids endogenously generated NO that paralleled the production of ROS. With increasing spheroid size, eNOS expression was downregulated, whereas an upregulation of iNOS expression was observed. In parallel, NO generation declined, as evaluated by the NO indicator diaminofluorescein‐2 diacetate (DAF‐2DA), suggesting that NO generation in DU‐145 tumor spheroids is mainly mediated by eNOS. Elevation of ROS by treatment of tumor spheroids with either buthionine sulfoximine (BSO) or hydrogen peroxide resulted in upregulation of eNOS, whereas iNOS was downregulated. Furthermore, eNOS expression was increased by epidermal growth factor (EGF) in a redox‐sensitive manner. Upregulation of eNOS after treatment with hydrogen peroxide was apparently transduced through receptor tyrosine kinase signaling pathways since it was abolished by the protein kinase C (PKC) inhibitor bisindolylmaleimide‐1 (BIM‐1), the p21ras inhibitor S‐trans‐trans‐farnesylthiosalicylic acid (FTS), the c‐Raf inhibitor ZM 336372 and PD98059, which inhibits ERK1/2 activation. Endogenous NO may serve to escape from oxidative stress‐induced apoptosis since treatment of tumor spheroids with the NO scavenger 2‐(4‐carboxyphenyl)‐4,4,5,5‐tetramethyl imidazoline‐1‐oxyl 3‐oxide (carboxy‐PTIO) as well as the NO synthase inhibitor N‐ω‐amino‐L‐arginine (L‐NAA) increased cleaved caspase‐3. Consequently, lowering intracellular NO levels with either L‐NAA or PTIO significantly raised ROS levels, indicating that endogenously generated NO may play a role as a ROS scavenger, thereby protecting exponentially growing tumor spheroids from ROS‐induced apoptosis. © 2003 Wiley‐Liss, Inc.
Overexpression of cadherins suppresses pulmonary metastasis of osteosarcoma in vivo
Authors: Kashima Takeshi , Nakamura Kazuya , Kawaguchi Jitsutaro , Takanashi Masakatsu , Ishida Tsuyoshi , Aburatani Hiroyuki , Kudo Akira , Fukayama Masashi , Grigoriadis Agamemnon E. 
Published: February 2003

AbstractOsteosarcoma by nature shows aggressive pulmonary metastasis; however, the underlying molecular mechanisms remain unclear. We previously showed that N‐cadherin and cadherin‐11 (OB‐cadherin), which are highly expressed in normal osteoblasts, are anomalously expressed in human osteosarcoma (Kashima et al., Am J Pathol 1999;155:1549–55). In the present study, we examined the role of cadherins in osteosarcoma metastasis using the mouse osteosarcoma cell line Dunn and its highly metastatic subline LM8. Oligonucleotide array and RT‐PCR analyses demonstrated that Dunn and LM8 cells did not express appreciable levels of several members of the cadherin family, and Western blot analysis confirmed that Dunn and LM8 cells did not express P‐cadherin, E‐cadherin, N‐cadherin or cadherin‐11 protein. We therefore investigated the functional consequences of cadherin overexpression on cell migration and in vivo metastatic potential of LM8 cells. Several LM8 clones were isolated which expressed exogenous N‐cadherin and cadherin‐11 localized to the cell membrane and able to bind to β‐catenin. Overexpression of N‐cadherin or cadherin‐11 in LM8 cells did not affect cell proliferation but caused an inhibitory effect on cell migration in vitro. In vivo analysis showed that N‐cadherin‐ and cadherin‐11‐overexpressing cells exhibited a marked reduction in their ability to form pulmonary metastases, with significant decreases in lung weight and the number and weight of metastatic lesions, as well as the size and weight of primary lesions at the s.c.‐inoculated site. These observations demonstrate that disruption of N‐cadherin‐ and cadherin‐11‐mediated cell–cell adhesion is critical in the pulmonary metastasis of osteosarcoma. © 2002 Wiley‐Liss, Inc.
Differential expression of genes induced by resveratrol in LNCaP cells: P53‐mediated molecular targets
Authors: Narayanan Bhagavathi A. , Narayanan Narayanan K. , Re Gian G. , Nixon Daniel W. 
Published: February 2003

AbstractProstate cancer prevention by key elements present in human nutrients derived from plants and fruits has been confirmed in various cell cultures and tumor models. Resveratrol (RE), a phytoalexin, induces remarkable inhibitory effects in prostate carcinogenesis via diverse cellular mechanisms associated with tumor initiation, promotion and progression. Earlier studies have shown that RE alters the expression of genes involved in cell cycle regulation and apoptosis, including cyclins, cdks, p53 and cdk inhibitors. However, most of the p53‐controlled effects related to the role of RE in transcription either by activation or repression of a sizable number of primary and secondary target genes have not been investigated. Our study examined whether RE activates a cascade of p53‐directed genes that are involved in apoptosis mechanism(s) or whether it modifies the androgen receptor and its co‐activators directly or indirectly and induces cell growth inhibition. We demonstrate by DNA microarray, RT‐PCR, Western blot and immunofluorescence analyses that treatment of androgen‐sensitive prostate cancer cells (LNCaP) with 10−5 M RE for 48 hr downregulates prostate‐specific antigen (PSA), AR co‐activator ARA 24 and NF‐kB p65. Altered expression of these genes is associated with an activation of p53‐responsive genes such as p53, PIG 7, p21Waf1‐Cip1, p300/CBP and Apaf‐1. The effect of RE on p300/CBP plays a central role in its cancer preventive mechanisms in LNCaP cells. Our results implicate activation of more than one set of functionally related molecular targets. At this point we have identified some of the key molecular targets associated with AR and p53 target genes. These findings point to the need for further extensive studies on AR co‐activators, such as p300, its central role in post‐translational modifications such as acetylation of p53 and/or AR by RE in a time‐ and dose‐dependent manner at different stages of prostate cancer that will fully elucidate the role of RE as a chemopreventive agent for prostate cancer in humans. © 2003 Wiley‐Liss, Inc.
CYP enzyme polymorphisms and susceptibility to HCV‐related chronic liver disease and liver cancer
Authors: Silvestri Laura , Sonzogni Laura , De Silvestri Annalisa , Gritti Chiara , Foti Luciana , Zavaglia Claudio , Leveri Michela , Cividini Agostino , Mondelli Mario U. , Civardi Emilio , Silini Enrico M. 
Published: February 2003

AbstractCancer risk can be influenced by the exposure to endogenous or environmental toxins. Polymorphic enzymes involved in the metabolic activation/detoxification of carcinogens may account for individual variations of risk. We studied the polymorphisms of five enzymes of the P450 superfamily, CYP1A1, CYP1A2, CYP2D6, CYP2E1 and CY3A4, as risk factors for liver disease progression and cancer in hepatitis C virus‐infected patients. CYP genotyping was performed by polymerase chain reaction (PCR) restriction fragment length polymorphism or allele‐specific PCR. Different stages of disease were considered, as follows: 90 asymptomatic carriers and 87 chronic hepatitis, 92 cirrhosis and 91 hepatocellular carcinoma (HCC) cases. Reference allele frequencies were obtained from 99 blood donors. Allele distributions among categories were compared using the χ2 test. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated to express relative risks. Independent associations were modeled by correspondence analysis and logistic regression. Frequencies of the CYP1A1 highly inducible alleles, MspI m2 and Val, were increased in liver disease patients compared with carriers; no specific association with HCC was found. The high‐activity CYP2E1 c2 allele was underrepresented among HCC patients with respect to other HCV categories, including cirrhosis. CYP2D6 poor metabolizer (PM) genotypes were significantly more frequent in healthy subjects (7.1%) and carriers (11.1%) than in hepatitis/cirrhosis (4.6%) and HCC (1.2%) patients. This was confirmed by multivariable analysis. PM genotypes protected against progressive disease as ORs reduced proportionally to stage. The age at diagnosis for HCC was anticipated in non‐PM individuals. No differences were seen for CYP1A2 and CYP3A4 genes. Polymorphic variants of CYP genes may contribute to the progression of liver disease and HCC risk in HCV‐infected subjects. © 2003 Wiley‐Liss, Inc.
Polyamine biosynthesis inhibition enhances HSV‐1 thymidine kinase/ganciclovir‐mediated cytotoxicity in tumor cells
Authors: Pasanen Tiina , Karppinen Anne , Alhonen Leena , Jänne Juhani , Wahlfors Jarmo 
Published: February 2003

AbstractCancer gene therapy with the aid of herpes simplex virus type 1 thymidine kinase gene (HSV‐TK) and anti‐herpes drug ganciclovir (GCV) has been widely used and its efficacy has been demonstrated in a variety of different malignant cells and animal tumor models. It is also commonly accepted, however, that this gene therapy regimen needs to be enhanced for a true clinical success. We studied whether polyamine biosynthesis inhibition by 2‐difluoromethylornithine (DFMO), a clinically tested and well‐tolerated chemotherapeutic drug, can increase the cytotoxicity of HSV‐TK/GCV in 9L rat glioma cells. Our initial experiments showed that polyamine depletion actually protected the cells from cytotoxicity if GCV treatment was started too early after removal of DFMO. Analyses of cell growth, intracellular polyamine pools and cell cycle phase distribution suggested that later initiation of GCV treatment would be more beneficial due to increased proportion of cells in the middle of the cell cycle S phase. When the cells were exposed to GCV 3 or 4 days after removal of DFMO from growth medium, the cytotoxicity was increased up to 2.5‐fold. We also verified whether cell cycle blockage per se could yield similar effect as DFMO. Our results from serum deprivation experiments showed that, despite of apparent cell growth and cell cycle phase distribution effects, serum starvation was weaker enhancer of HSV‐TK/GCV cytotoxicity than DFMO. Finally, the general utility of HSV‐TK/GCV + DFMO combination was tested in another tumor cell type, human prostate carcinoma cell line DU‐145. DFMO sensitized these cells to HSV‐TK/GCV cytotoxicity, but the effect was less prominent than in 9L cells. In conclusion, we have demonstrated that a correctly timed induction of DFMO‐mediated polyamine biosynthesis inhibition can enhance the efficiency of HSV‐TK/GCV gene therapy in vitro. The observed synergistic effect is potentially useful in clinical trials because, as opposed to use of other cell cycle‐altering drugs, DFMO has already been tested in the treatment of human tumors and used as chemo preventive regimen with excellent tolerability. © 2003 Wiley‐Liss, Inc.
Effects of granulocyte‐macrophage colony‐stimulating factor and foreign helper protein as immunologic adjuvants on the T‐cell response to vaccination with tyrosinase peptides
Authors: Scheibenbogen Carmen , Schadendorf Dirk , Bechrakis Nikolaos E. , Nagorsen Dirk , Hofmann Udo , Servetopoulou Fotini , Letsch Anne , Philipp Armin , Foerster Michael H. , Schmittel Alexander , Thiel Eckhard , Keilholz Ulrich 
Published: February 2003

AbstractImmunologic adjuvants are used to augment the immunogenicity of MHC class I–restricted peptide vaccines, but this effect has rarely been systematically evaluated in a clinical trial. We have investigated, in a phase I study, whether addition of the 2 adjuvants GM‐CSF and KLH can enhance the T‐cell response to MHC class I peptide vaccines. Forty‐three high‐risk melanoma patients who were clinically free of disease received 6 vaccinations with MHC class I–restricted tyrosinase peptides alone, with either GM‐CSF or KLH or with a combination of both adjuvants. The primary end point was induction of tyrosinase‐specific T cells, and serial T‐cell monitoring was performed in unstimulated peripheral blood samples before and after the second, fourth and sixth vaccinations by ELISPOT assay. Tyrosinase‐specific IFN‐γ‐producing T cells were detected as early as 2 weeks after the second vaccination in 5 of 9 patients vaccinated with tyrosinase peptides in combination with GM‐CSF and KLH but not in any patient vaccinated with tyrosinase peptides without adjuvants or in combination with either adjuvant alone. After 6 vaccinations, tyrosinase‐specific T cells were found in patients immunized with peptides either without adjuvants (3 of 9 patients) or in combination with the single adjuvant GM‐CSF (4 of 9 patients) but not with KLH (0 of 10 patients). Our results suggest that addition of either GM‐CSF or KLH as a single adjuvant has little impact on the immunogenicity of tyrosinase peptides. The combined application of GM‐CSF and KLH was associated with early induction of T‐cell responses. © 2003 Wiley‐Liss, Inc.
Frequent monoallelic deletion of PTEN and its reciprocal associatioin with PIK3CA amplification in gastric carcinoma
Authors: Byun Do‐Sun , Cho Kyucheol , Ryu Byung‐Kyu , Lee Min‐Goo , Park Jae‐Il , Chae Kwon‐Seok , Kim Hyo‐Jong , Chi Sung‐Gil 
Published: February 2003

AbstractMutational alterations of PTEN and PIK3CA, which negatively and positively regulate PI3‐kinase activity, respectively, have been observed in many types of human cancer. To explore the implication of PTEN and PIK3CA mutations in gastric tumorigenesis, we characterized the expression and mutation status of the genes in 126 gastric tissues and 15 cell lines. Expression of PTEN transcript was abnormally low in 5 of 15 (33%) cell lines and 20 of 55 (36%) primary carcinomas, whereas 0 of 71 noncancerous tissues including 16 benign tumors showed altered expression. Allelotyping analysis using an intragenic polymorphism (IVS4+109) revealed that 14 of 30 (47%) informative cases carried LOH of the gene, which is closely linked to low expression. The LOH rate was significantly higher in advanced tumors [12 of 19 (63%)] compared to early‐stage tumors [2 of 11 (18%)] and more frequent in poorly differentiated tumors [9 of 13 (69%)] than well‐ or moderately differentiated tumors [5 of 17 (29%)]. Interestingly, however, none of the LOH tumors carried mutational disruption of the remaining allele, suggesting haploinsufficiency of PTEN in gastric tumorigenesis. Methylation studies revealed that PTEN pseudogene, but not PTEN, is methylated in cell lines and primary tumors, indicating that PTEN is not a target of epigenetic silencing in gastric cancers and that the pseudogene should be considered more carefully in methylation analysis of the PTEN promoter. Genomic amplification of PIK3CA was found in 9 of 15 (60%) cell lines and 20 of 55 (36.4%) primary tumors but in no noncancerous tissues. Furthermore, PIK3CA amplification was predominantly detected in tumors with no PTEN alterations, suggesting that mutations of PTEN and PIK3CA are mutually exclusive events in gastric tumorigenesis. Amplification of PIK3CA was strongly associated with increased expression of PIK3CA transcript and elevated levels of phospho‐AKT. Collectively, our data reveal that 13 of 15 (87%) gastric cell lines and 31 of 55 (56%) primary carcinomas harbored either amplification of PIK3CA or abnormal reduction of PTEN. Mutually exclusive alterations of PTEN and PIK3CA also suggest that mutations of either gene could activate the PI3‐kinase/AKT signaling pathway, which is directly linked to the malignant progression of gastric tumor cells. © 2003 Wiley‐Liss, Inc.
Decreased DNA repair gene expression among individuals exposed to arsenic in United States drinking water
Authors: Andrew Angeline S. , Karagas Margaret R. , Hamilton Joshua W. 
Published: February 2003

AbstractArsenic is well established as a human carcinogen, but its precise mechanism of action remains unknown. Arsenic does not directly damage DNA, but may act as a carcinogen through inhibition of DNA repair mechanisms, leading indirectly to increased mutations from other DNA damaging agents. The molecular mechanism underlying arsenic inhibition of nucleotide excision repair after UV irradiation (Hartwig et al., Carcinogenesis 1997;18:399–405) is unknown, but could be due to decreased expression of critical genes involved in nucleotide excision repair of damaged DNA. This hypothesis was tested by analyzing expression of repair genes and arsenic exposure in a subset of 16 individuals enrolled in a population based case‐control study investigating arsenic exposure and cancer risk in New Hampshire. Toenail arsenic levels were inversely correlated with expression of critical members of the nucleotide excision repair complex, ERCC1 (r2 = 0.82, p < 0.0001), XPF (r2 = 0.56, p < 0.002), and XPB (r2 = 0.75, p < 0.0001). The internal dose marker, toenail arsenic level, was more strongly associated with changes in expression of these genes than drinking water arsenic concentration. Our findings, based on human exposure to arsenic in a US population, show an association between biomarkers of arsenic exposure and expression of DNA repair genes. Although our findings need verification in a larger study group, they are consistent with the hypothesis that inhibition of DNA repair capacity is a potential mechanism for the co‐carcinogenic activity of arsenic. © 2003 Wiley‐Liss, Inc.
Recirculating and germinal center B cells differentiate into cells responsive to polysaccharide antigens
Authors: Vinuesa Carola G. , Sze Daniel M‐Y. , Cook Matthew C. , Toellner Kai‐Michael , Klaus Gerry G. B. , Ball Jennifer , MacLennan Ian C. M. 
Published: February 2003

AbstractAntibodies against bacterial capsular polysaccharides play a critical protective role. Responses to these antigens can occur without the help or control of T cells and are associated with marginal zone (MZ) B cells. Capsular antigens are diverse and some cross‐react with self‐carbohydrate epitopes. This diversity may explain the recruitment of non‐autoreactive recirculating B cells and memory B cells to the MZ in addition to other B cells, some of which are weakly autoreactive cells, that are recruited to the MZ without entering the recirculating pool. To test whether memory B cells respond to polysaccharide‐based antigens, mice with hapten‐specific memory B cells were challenged with hapten‐polysaccharide. Hapten‐specific plasma cells producing high affinity antibody with IgV‐region mutations were induced. To test whether naive recirculating B cells can form MZ cells that respond to polysaccharide, recirculating B cells from lymph nodes were transferred into Rag‐1‐deficient mice. MZ cells differentiated from the donor cells without proliferation or T cell help and responded to polysaccharide‐based antigen. The differentiation of B cells both from germinal centers and the recirculating pool to the MZ phenotype is likely to make an important contribution to the repertoire of B cells that respond to polysaccharide antigens.
TRANCE together with IL‐7 induces pre‐B cells to proliferate
Authors: Kato Ibuki , Sato Hiromu , Kudo Akira 
Published: February 2003

AbstractTRANCE (TNF‐related activation‐induced cytokine)‐deficient mice completely lack osteoclasts, and develop severe osteopetrosis. These mice also show a defect in their pre‐B cell differentiation. In the present study, the expression of TRANCE was examined in pre‐B cell lines using flow cytometry and reverse transcription‐PCR. Three pre‐B cell lines, 18‐81, B3P816‐1, and 38B9, expressed TRANCE on their surface, and two pre‐B cell lines, 70Z/3 and NFS5, at the late pre‐B cell stage, expressed it at low levels, although their mRNA expression was normal. Another pre‐B cell line, 38‐C‐13, at the intermediate stage between pre‐B and immature B cells, did not express TRANCE. The IL‐7‐dependent pre‐B cell line PreBR, which expresses the pre‐B cell receptor on the cellsurface, also expressed TRANCE. When differentiation of PreBR cells was induced in vitro by removing IL‐7 from cultures, TRANCE expression dropped; it was restored by the addition of IL‐7, suggesting that TRANCE functions in cooperation with IL‐7. To examine the function of TRANCE, we introduced the TRANCE gene into PreBR cells and established two transfectants that constitutively expressed TRANCE, even in the absence of IL‐7. In these transfectants, after removal of IL‐7, the number of cells that succeeded in κ chain rearrangement was decreased to one third; and CD40 expression decreased to less than one tenth. Moreover, the percentage of cells in the S/G2/M phase was increased by 50% over the mock transfectant. These findings indicate that, before κ chain rearrangement occurs, TRANCE together with IL‐7 induces pre‐B cells to proliferate and makes this rearrangement more efficient.