bluuebunny/crossref_metadata_2025_split huggingface dataset:
Concentrations of parabens in human breast tumours
Authors: Darbre P. D. , Aljarrah A. , Miller W. R. , Coldham N. G. , Sauer M. J. , Pope G. S. 
Published: January 2004

AbstractParabens are used as preservatives in many thousands of cosmetic, food and pharmaceutical products to which the human population is exposed. Although recent reports of the oestrogenic properties of parabens have challenged current concepts of their toxicity in these consumer products, the question remains as to whether any of the parabens can accumulate intact in the body from the long‐term, low‐dose levels to which humans are exposed. Initial studies reported here show that parabens can be extracted from human breast tissue and detected by thin‐layer chromatography. More detailed studies enabled identiﬁcation and measurement of mean concentrations of individual parabens in samples of 20 human breast tumours by high‐pressure liquid chromatography followed by tandem mass spectrometry. The mean concentration of parabens in these 20 human breast tumours was found to be 20.6 ± 4.2 ng g−1 tissue. Comparison of individual parabens showed that methylparaben was present at the highest level (with a mean value of 12.8 ± 2.2 ng g−1 tissue) and represents 62% of the total paraben recovered in the extractions. These studies demonstrate that parabens can be found intact in the human breast and this should open the way technically for more detailed information to be obtained on body burdens of parabens and in particular whether body burdens are different in cancer from those in normal tissues. Copyright © 2004 John Wiley & Sons, Ltd.
Colon cancer specific nuclear matrix protein alterations in human colonic adenomatous polyps
Authors: Brünagel Gisela , Schoen Robert E. , Getzenberg Robert H. 
Published: January 2004

AbstractMost colon cancers arise within preexisting adenomatous polyps or adenomas. The slow evolution from the non‐invasive premalignant lesion, the adenomatous polyp, to invasive cancer supports a strategy of early detection. Recently, we identified unique nuclear matrix proteins (NMPs) specific for colon cancer (CC2, CC3, CC4, CC5). Most of the NMPs identified are common to all cell types, but several identified NMPs are tissue and cell line specific. The objective of this study is to describe and characterize the NMP profile of premalignant adenomatous colon polyps. Specifically when in the adenoma‐carcinoma sequence four specific colon cancer NMPs, previously described, appear. Using two‐dimensional (2‐D) gel analysis 20 colon polyps (one juvenile polyp, six tubular adenoma (TA), seven tubulovillous adenoma (TVA), six TVA with focal high‐grade dysplasia (HGD), were analyzed for the presence of four (CC2, CC3, CC4, CC5) specific NMPs. CC2 was not seen in any of the premalignant polyps. CC5 was present in only two premalignant TVA with HGD and in one TA. CC3 and CC4 were present in most adenomas. None of the NMPs were seen in the juvenile polyp, which is not considered to be a precursor of colon cancer. CC2 and CC5 are NMPs expressed at the junction of an advanced adenoma and invasive colorectal cancer. CC3 and CC4 are expressed earlier in the evolution of adenomatous polyps. Development of an assay to these proteins may serve as a new method for early detection of colorectal cancer. © 2003 Wiley‐Liss, Inc.
Cell cycle checkpoints and their impact on anticancer therapeutic strategies
Authors: Eastman Alan 
Published: January 2004

AbstractCells contain numerous pathways designed to protect them from the genomic instability or toxicity that can result when their DNA is damaged. The p53 tumor suppressor is particularly important for regulating passage through G1 phase of the cell cycle, while other checkpoint regulators are important for arrest in S and G2 phase. Tumor cells often exhibit defects in these checkpoint proteins, which can lead to hypersensitivity; proteins in this class include ataxia–telangiectasia mutatated (ATM), Meiotic recanbination 11 (Mre11), Nijmegen breakage syndrome 1 (Nbs 1), breast cancer susceptibility genes 1 and 2 (BRCA1), and (BRCA2). Consequently, tumors should be assessed for these specific defects, and specific therapy prescribed that has high probability of inducing response. Tumors defective in p53 are frequently considered resistant to apoptosis, yet this defect also provides an opportunity for targeted therapy. When their DNA is damaged, p53‐defective tumor cells preferentially arrest in S or G2 phase where they are susceptible to checkpoint inhibitors such as caffeine and UCN‐01. These inhibitors preferentially abrogate cell cycle arrest in p53‐defective cells, driving them through a lethal mitosis. Wild type p53 can prevent abrogation of arrest by elevating levels of p21waf1 and decreasing levels of cyclins A and B. During tumorigenesis, tumor cells frequently loose checkpoint controls and this facilitates the development of the tumor. However, these defects also represent an Achilles heel that can be targeted to improve current therapeutic strategies. © 2003 Wiley‐Liss, Inc.
Platelet‐derived growth factor‐BB phosphorylates heat shock protein 27 in cardiac myocytes
Authors: Takenaka Motoki , Matsuno Hiroyuki , Ishisaki Akira , Nakajima Keiichi , Hirade Kouseki , Takei Mariko , Yasuda Eisuke , Akamatsu Shigeru , Yoshimi Naoki , Kato Kanefusa , Kozawa Osamu 
Published: January 2004

AbstractIt is recognized that heat shock protein 27 (HSP27) is highly expressed in heart. In the present study, we investigated whether platelet‐derived growth factor (PDGF) phosphorylates HSP27 in mouse myocytes, and the mechanism underlying the HSP27 phosphorylation. Administration of PDGF‐BB induced the phosphorylation of HSP27 at Ser‐15 and ‐85 in mouse cardiac muscle in vivo. In primary cultured myocytes, PDGF‐BB time dependently phosphorylated HSP27 at Ser‐15 and ‐85. PDGF‐BB stimulated the phosphorylation of p44/p42 mitogen‐activated protein (MAP) kinase, p38 MAP kinase, and stress‐activated protein kinase/c‐Jun N‐terminal kinase (SAPK/JNK) among the MAP kinase superfamily. SB203580, a specific inhibitor of p38 MAP kinase, reduced the PDGF‐BB‐stimulated phosphorylation of HSP27 at both Ser‐15 and ‐85, and phosphorylation of p38 MAP kinase. However, PD98059, a specific inhibitor of MEK, or SP600125, a specific inhibitor of SAPK/JNK, failed to affect the HSP27 phosphorylation. These results strongly suggest that PDGF‐BB phosphorylates HSP27 at Ser‐15 and ‐85 via p38 MAP kinase in cardiac myocytes. © 2003 Wiley‐Liss, Inc.
PPARγ1 synthesis and adipogenesis in C3H10T1/2 cells depends on S‐phase progression, but does not require mitotic clonal expansion
Authors: Cho Young C. , Jefcoate Colin R. 
Published: January 2004

AbstractAdipogenesis is typically stimulated in mouse embryo fibroblast (MEF) lines by a standard hormonal combination of insulin (I), dexamethasone (D), and methylisobutylxanthine (M), administered with a fresh serum renewal. In C3H10T1/2 (10T1/2) cells, peroxisome proliferator‐activated receptor γ1 (PPARγ1) expression, an early phase key adipogenic regulator, is optimal after 36 h of IDM stimulation. Although previous studies provide evidence that mitotic clonal expansion of 3T3‐L1 cells is essential for adipogenesis, we show, here, that 10T1/2 cells do not require mitotic clonal expansion, but depend on cell cycle progression through S‐phase to commit to adipocyte differentiation. Exclusion of two major mitogenic stimuli (DM without insulin and fresh serum renewal) from standard IDM protocol removed mitotic clonal expansion, but sustained equivalent PPARγ1 synthesis and lipogenesis. Different S‐phase inhibitors (aphidicolin, hydroxyurea, l‐mimosine, and roscovitin) each arrested cells in S‐phase, under hormonal stimulation, and completely blocked PPARγ1 synthesis and lipogenesis. However, G2/M inhibitors effected G2/M accumulation of IDM stimulated cells and prevented mitosis, but fully sustained PPARγ1 synthesis and lipogenesis. DM stimulation with or without fresh serum renewal elevated DNA synthesis in a proportion of cells (measured by BrdU labeling) and accumulation of cell cycle progression in G2/M‐phase without complete mitosis. By contrast, standard IDM treatments with fresh serum renewal caused elevated DNA synthesis and mitotic clonal expansion while achieved equivalent level of adipogenesis. At most, one‐half of the 10T1/2 mixed cell population differentiated to mature adipocytes, even when clonally isolated. PPARγ was exclusively expressed in the cells that contained lipid droplets. IDM stimulated comparable PPARγ1 synthesis and lipogenesis in isolated cells at low cell density (LD) culture, but in about half of the cells and with sensitivity to G1/S, but not G2/M inhibitors. Importantly, growth arrest occurred in all differentiating cells, while continuous mitotic clonal expansion occurred in non‐differentiating cells. Irrespective of confluence level, 10T1/2 cells differentiate after progression through S‐phase, where adipogenic commitment induced by IDM stimulation is a prerequisite for PPARγ synthesis and subsequent adipocyte differentiation. © 2003 Wiley‐Liss, Inc.
Breast cancer cells induce osteoblast apoptosis: A possible contributor to bone degradation
Authors: Mastro Andrea M. , Gay Carol V. , Welch Danny R. , Donahue Henry J. , Jewell Jennifer , Mercer Robyn , DiGirolamo Douglas , Chislock Elizabeth M. , Guttridge Kristin 
Published: January 2004

AbstractBreast cancer cells exhibit a predilection for metastasis to bone. There, the metastases usually bring about bone loss with accompanying pain and loss of function. One way that breast cancer cells disrupt the normal pattern of bone remodeling is by activating osteoclasts, the bone degrading cells. Nevertheless, targeting the osteoclasts does not cure the disease or result in bone repair. These observations indicate that osteoblast function also may be compromised. The objective of this study was to investigate the interaction of metastatic breast cancer cells with osteoblasts. Human metastatic breast cancer cells, MDA‐MB‐435 or MDA‐MB‐231, or their conditioned media were co‐cultured with a human osteoblast line hFOB1.19. The breast cancer cells caused an increase in the prevalence of apoptotic osteoblasts. Apoptotic osteoblasts detected by the TUNEL assay or by caspase activity increased approximately two to fivefold. This increase was not seen with non‐metastatic MDA‐MB‐468 cells. In an investigation of the mechanism, it was determined that the hFOB1.19 cells expressed fas and that fas was functional. Likewise the hFOB1.19 cells were susceptible to TNF‐α, but this cytokine was not detected in the conditioned medium of the breast cancer cells. This study indicates that osteoblasts are the target of breast cancer cell‐induced apoptosis, but fas/fas‐ligand and TNF‐α, two common initiators of cell death, are probably not involved in this aspect of the metastases/bone cell axis. There are several mechanisms that remain to be explored in order to determine how breast cancer cells bring about osteoblast apoptosis. Even though the specific initiator of apoptosis remains to be identified, the results of this study suggest that the mechanism is likely to be novel. © 2003 Wiley‐Liss, Inc.
Regulatory factor X2 (RFX2) binds to the H1t/TE1 promoter element and activates transcription of the testis‐specific histone H1t gene
Authors: Wolfe Steven A. , Wilkerson Donald C. , Prado Susan , Grimes Sidney R. 
Published: January 2004

AbstractTranscription of the mammalian testis‐specific linker histone H1t gene occurs only in pachytene primary spermatocytes during spermatogenesis. Studies of the wild type (Wt) and mutant H1t promoters in transgenic mice show that transcription of the H1t gene is dependent upon the TE promoter element. We purified an 85 kDa protein from rat testis nuclear extracts using the TE1 subelement as an affinity chromatography probe and analysis revealed that the protein was RFX2. The TE1 element is essentially an X‐box DNA consensus element and regulatory factor X (RFX) binds specifically to this element. Polyclonal antibodies directed against RFX2 supershift the low mobility testis nuclear protein complex formed in electrophoretic mobility shift assays (EMSA). RFX2 derived from primary spermatocytes, where the transcription factor is relatively abundant, binds with high affinity to the TE1 element. Coexpression of RFX2 together with an H1t promoter/reporter vector activates the H1t promoter in a cultured GC‐2spd germinal cell line, but mutation of either the TE1 subelement or the TE2 subelements represses activity. These observations lead us to conclude that the TE1 and TE2 subelements of the testis‐specific histone H1t promoter are targets of the transcription factor RFX2 and that this factor plays a key role in activating transcription of the H1t gene in primary spermatocytes. Published 2003 Wiley‐Liss, Inc.
Differentially up‐regulated genes in proliferating porcine neonatal pancreas cells caused by epidermal growth factor
Authors: Jeon Sung Yoon , Baek Kwang‐Hyun , Kim Yong‐Soo , Park Chung‐Gyu , Kwon Hyuk Sang , Ko Seung Hyun , Song Ki‐Ho , Yoo Soon Jib , Son Hyun Shik , Cha Bong Yun , Lee Kwang Woo , Son Ho Young , Kang Sung Koo , Yoon Kun‐Ho 
Published: January 2004

AbstractPancreatic duct cells are considered to be a major source for β‐cell regeneration or neogenesis. Although epidermal growth factor (EGF) is a well‐known important growth factor for pancreas development, the control of pancreatic duct cell growth and differentiation by EGF is poorly understood. In this study, we focused on identifying the genes that were differentially up‐regulated in response to EGF stimulation using monolayer cultured porcine neonatal pancreas cells. Cells were obtained from 1 to 3 day old pigs, dispersed and cultured for 8 days. Monolayer cultured porcine pancreas cells were comprised of duct cells and some endocrine and mesenchymal cells (75.2 ± 15.1, 19.6 ± 4.9, and 9.5 ± 3.1%, respectively). After 16 h in serum free media, cells were treated with 100 μg/L EGF for 24 h. Differentially expressed genes were screened by subtractive hybridization. 3H‐thymidine uptake was significantly increased by EGF with time (untreated vs. 24 h treated, untreated vs. 48 h treated: 305.5 ± 3.5 cpm vs. 380.3 ± 17.3 cpm (P < 0.05), 309.2 ± 4.51 vs. 929 ± 9.19 cpm, (P < 0.005), respectively). Three hundred and fify cDNA clones were obtained by subtractive hybridization and the inserts were confirmed in 161 colonies and then sequenced. Finally, we found increased mRNA expression of five unknown and five known genes, including cytochrome c oxidase subunit I (COI), cyclooxygenase‐2 (COX‐2), matrix metalloproteinase‐13 (MMP‐13), Wiskott–Aldrich syndrome protein interacting protein (WASPIP), and hyaluronan synthase‐2 (HAS‐2). We confirmed the up‐regulation of these genes by Northern blot and semi‐quantitative RT‐PCR at various time points. The present findings opened new targets for the research on the mechanisms of pancreatic duct cell proliferation by EGF. © 2003 Wiley‐Liss, Inc.
Constitutive and inducible expression of cytochromes P4501A (CYP1A1 and CYP1A2) in normal prostate and prostate cancer cells
Authors: Sterling Kenneth M. , Cutroneo Kenneth R. 
Published: January 2004

AbstractConstitutive and benzo[a]pyrene (B[a]P) inducible expression of CYP1A1 and CYP1A2 in prostate cancer and normal prostate epithelial cells were examined by immunoblotting. Androgen independent prostate cancer cell lines DU145 and PC3 have constitutive expression of CYP1A and CYP1A1 and CYP1A2, respectively. Four micromolar B[a]P did not appear to induce CYP1A1 or CYP1A2 expression in DU145 or PC3 cells. The androgen dependent prostate cancer cell line, LnCap, also has constitutive expression of CYP1A1 and CYP1A2. However, both CYP1A1 and CYP1A2 are induced by treatment of LnCap cells with 4 μM B[a]P. Untreated normal prostate and primary prostate tumor cells have no detectable CYP1A1 expression. Treatment with 4 μM B[a]P induced CYP1A1 expression in both normal and primary tumor prostate cells. Constitutive CYP1A2 expression was detected in normal prostate cells with little or no induction by exposure to 4 μM B[a]P. Primary prostate tumor cells did not show constitutive expression of CYP1A2. However, CYP1A2 was induced by 4 μM B[a]P in primary prostate tumor cells. These observations indicate that hormonal and cancer specific factors affect the expression and induction of the phase I metabolic enzymes, CYP1A1 and CYP1A2 in prostate cells. These observations may be related to the potential smoking‐linked higher risk of prostate cancer development and morbidity of prostate cancer patients who smoke. © 2003 Wiley‐Liss, Inc.
Cleavage of p130Cas in anoikis
Authors: Wei Lin , Yang Yu , Zhang Xing , Yu Qiang 
Published: January 2004

Abstractp130Cas is a multifunctional signaling adaptor protein. It integrates and relays signals generated from a variety of extracellular stimuli and regulates a number of cellular activities including cell death. In this study, we analyzed the regulation and function of p130Cas in anoikis, a type of apoptosis caused by disruption of cell‐matrix interactions. We found that p130Cas was specifically cleaved during anoikis in anoikis‐sensitive epithelial cells, but not in anoikis‐resistant tumor cells. There is a close correlation between p130Cas cleavage and anoikis. Furthermore, we found that the cleavage of p130Cas, as well as another focal adhesion component FAK, is different from that of caspase substrate PARP and spectrin. Although caspases and calpain were found to be involved in the cleavage of p130Cas, there appear to be other unidentified proteases that are mainly responsible for the cleavage of p130Cas, particularly at the early stage of anoikis. Overexpression of the p130Cas cleavage product induced apoptosis. Taken together, these data suggest that there are novel proteases involved in the cleavage of p130Cas during anoikis, which may be functionally involved in the onset of anoikis. p130Cas may have a dual role in the regulation of anoikis. On one hand, it mediates a survival signal from cell‐matrix interactions when cells are attached to the extracellular matrix. On the other hand, it participates in executing cell death when cell‐matrix interactions are disrupted. These observations provide new insights into the understanding of the function of p130Cas and the molecular mechanism of anoikis. © 2003 Wiley‐Liss, Inc.
Mediating of caspase‐independent apoptosis by cadmium through the mitochondria‐ROS pathway in MRC‐5 fibroblasts
Authors: Shih Chwen‐Ming , Ko Wun‐Chang , Wu Jui‐Sheng , Wei Yau‐Huei , Wang Leng‐Fang , Chang E‐E. , Lo Tsui‐Yun , Cheng Huey‐Hwa , Chen Chien‐Tsu 
Published: January 2004

AbstractCadmium (Cd) is an environmental pollutant of global concern with a 10–30‐year biological half‐life in humans. Accumulating evidence suggests that the lung is one of the major target organs of inhaled Cd compounds. Our previous report demonstrated that 100 μM Cd induces MRC‐5 cells, normal human lung fibroblasts, to undergo caspase‐independent apoptosis mediated by mitochondrial membrane depolarization and translocation of apoptosis‐inducing factor (AIF) from mitochondria into the nucleus. Here, using benzyloxycarbonyl‐Val‐Ala‐Asp‐(ome) fluoromethyl ketone (Z‐VAD.fmk) as a tool, we further demonstrated that Cd could induce caspase‐independent apoptosis at concentrations varied from 25 to 150 μM, which was modulated by reactive oxygen species (ROS) scavengers, such as N‐acetylcysteine (NAC), mannitol, and tiron, indicating that ROS play a crucial role in the apoptogenic activity of Cd. Consistent with this notion, the intracellular hydrogen peroxide (H2O2) was 2.9‐fold elevated after 3 h of Cd treatment and diminished rapidly within 1 h as detected by flow cytometry with 2′,7′‐dichlorodihydrofluorescein diacetate (DCFH‐DA) staining. Using inhibitors of the mitochondrial electron transport chain (ETC) (oligomycin A and rotenone for complex I and V, respectively) and mitochondrial permeability transition pore (MPTP) (cyclosporin A and aristolochic acid), we coincidently found the ROS production, mitochondrial membrane depolarization, and apoptotic content were almost completely or partially abolished. As revealed by confocal microscopy staining with chloromethyl‐X‐rosamine (CMXRos) and an anti‐AIF antibody, the collapse of mitochondrial membrane potential induced by Cd (3 h‐treatment) was a prelude to the translocation of caspase‐independent pro‐apoptotic factor, AIF, into the nucleus (after 4 h of Cd treatment). In summary, this study demonstrated that, in MRC‐5 fibroblasts, Cd induced caspase‐independent apoptosis through a mitochondria‐ROS pathway. More importantly, we provide several lines of evidence supporting a role of mitochondrial ETC and MPTP in the regulation of caspase‐independent cell death triggered by Cd. © 2003 Wiley‐Liss, Inc.
Angiostatin‐induced inhibition of endothelial cell proliferation/apoptosis is associated with the down‐regulation of cell cycle regulatory protein cdk5
Authors: Sharma Meena R. , Tuszynski George P. , Sharma Mahesh C. 
Published: January 2004

AbstractEndothelial cells (ECs) are quiescent in normal blood vessels, but undergo rapid bursts of proliferation after vascular injury, hypoxia or induced by powerful angiogenic cytokines like fibroblast growth factor (bFGF) and vascular endothelial growth factor (VEGF). Deregulated proliferation of ECs facilitates angiogenic processes and promotes tumor growth. In dividing cells, cell cycle‐associated protein kinases, which are referred as cyclin‐dependent kinases (cdks), regulate proliferation, differentiation, senescence, and apoptosis. Cyclin‐dependent kinase‐5 (cdk5) is expressed in neuronal cells and plays an important role in neurite outgrowth, of neuronal migration and neurogenesis, its functions in non‐neuronal cells are unclear. Here, we show for the first time that the cdk5 is expressed at high levels in proliferating bovine aortic endothelial (BAE) cells, by contrast insignificant low levels of cdk5 expression in quiescent BAE cells. In addition, bFGF up‐regulates cdk5 expression in a dose‐dependent fashion. Interestingly, temporal expression data suggests that cdk5 expression is very low between 24–48 h, but high level of cdk5 expression was detected during 60–72 h. This later time corresponds to the time of completion of one cell cycle (doubling of cell population) of BAE cell culture. Angiostatin (AS), a powerful inhibitor of angiogenesis inhibits ECs proliferation in dose‐dependent manner with concomitant down‐regulation of cdk5 expression. The role of cdk5 in ECs, proliferation and apoptosis was confirmed by selective inhibition of cdk5 expression by the purine derivative roscovitine, which inhibits bFGF‐stimulated BAE cells proliferation and induces apoptosis in dose‐specific manner. By contrast, the roscovitine analog olomoucine, which is a specific inhibitor of cdk4, but not of cdk5 failed to affect ECs proliferation and apoptosis. These data suggest for the first time that neuron specific protein cdk5 may have significant role in the regulation of ECs proliferation, apoptosis, and angiogenesis and extends beyond its role in neurogenesis. © 2003 Wiley‐Liss, Inc.