bluuebunny/crossref_metadata_2025 huggingface dataset:
The Monocarboxylate Transporter 8 Linked to Human Psychomotor Retardation Is Highly Expressed in Thyroid Hormone-Sensitive Neuron Populations
Authors: Heuer Heike , Maier Michael K. , Iden Sandra , Mittag Jens , Friesema Edith C. H. , Visser Theo J. , Bauer Karl
Published: January 2005

Recent genetic analysis in several patients presenting a severe form of X-linked psychomotor retardation combined with abnormal thyroid hormone (TH) levels have revealed mutations or deletions in the gene of the monocarboxylate transporter 8 (MCT8). Because in vitro MCT8 functions as a TH transporter, the complex clinical picture of these patients indicated an important role for MCT8 in TH-dependent processes of brain development. To provide a clue to the cellular function of MCT8 in brain, we studied the expression of MCT8 mRNA in the murine central nervous system by in situ hybridization histochemistry. In addition to the choroid plexus structures, the highest transcript levels were found in neo- and allocortical regions (e.g. olfactory bulb, cerebral cortex, hippocampus, and amygdala), moderate signal intensities in striatum and cerebellum, and low levels in a few neuroendocrine nuclei. Colocalization studies revealed that MCT8 is predominantly expressed in neurons. Together with the spatiotemporal expression pattern of MCT8 during the perinatal period, these results strongly indicate that MCT8 plays an important role for proper central nervous system development by transporting TH into neurons as its main target cells.
Kainate/Estrogen Receptor Involvement in Rapid Estradiol Effects in Vitro and Intracellular Signaling Pathways
Authors: Matagne V. , Lebrethon M.-C. , Gérard A. , Bourguignon J.-P.
Published: January 2005

Although the interactions between sex steroids and GnRH have been extensively studied, little is known about the mechanism of estradiol (E2) effects on GnRH secretion. In the present study, we used retrochiasmatic hypothalamic explants of 50-d-old male rats, and we observed that E2 significantly increased the glutamate-evoked GnRH secretion in vitro within 15 min in a dose-dependent manner. E2 also significantly increased the l-arginine-evoked GnRH secretion. E2 effects were time dependent because the initially ineffective 10−9m concentration became effective after 5 h of incubation. The E2 effects involved the estrogen receptor (ER) α because they were similarly obtained with the specific ERα agonist 1,3,5-tris(4-hydroxyphenyl)-4-propyl-1H-pyrazole. The use of glutamate receptor agonists and antagonists indicated that E2 effects on GnRH secretion evoked by both glutamate and l-arginine involved the 2-amino-3-hydroxy-5-methyl-4-isoxazol propionic acid/kainate receptors. Similar E2 effects on the kainate-evoked secretion were observed throughout development in both sexes. The observation of similar E2 effects using explants containing the median eminence alone indicated that the median eminence was a direct target for E2 rapid effects on the glutamate-evoked GnRH secretion. The signaling pathways involved in E2 effects included an increase in intracellular calcium and the activation of protein kinase A, protein kinase C, and MAPK. It is concluded that E2 can stimulate the glutamate- and nitric oxide-evoked GnRH secretion in vitro through a rapid pathway involving the ER and kainate receptor as well as through a slower mechanism responding to lower E2 concentrations.
Novel Gender-Related Regulation of CYP2C12 Gene Expression in Rats
Authors: Endo Megumi , Takahashi Yoshiki , Sasaki Yasumasa , Saito Tetsuya , Kamataki Tetsuya
Published: January 2005

The expression of CYP2C12 by GH occurs in female but not in male rat livers. Direct injection of the CYP2C12 promoter-luciferase gene into male rat livers showed that the CYP2C12 promoter was active in both male and female rats. Thus, to further examine one or more factors that regulate the gender-related expression of CYP2C12, male rats were treated with trichostatin A, a specific inhibitor of histone deacetylase capable of condensing the chromatin structure. Interestingly, the expression of CYP2C12 by GH was seen even in the livers of male rats, indicating that histone deacetylase contributes to the suppression of CYP2C12 expression in male rats. Deoxyribonuclease I hypersensitive assay using nuclei from the livers of male or female rats revealed that the chromatin structure of the CYP2C12 gene was gender specific: a hypersensitive site at a position −4.2 kb containing GH-responsive element that bound to signal transducer and activator of transcription 5 (STAT5), termed as HS (hypersensitive site) 1, was specific for female rat livers, whereas a hypersensitive site at a position −3 kb, designated as HSm (male-specific hypersensitive site), was characteristic of male rat livers. A −3425/−3275 region within HSm functioned as a negative regulatory region, when the region was inserted in front of simian virus 40 promoter. Gel shift assay demonstrated that both CCAAT/enhancer-binding protein α and β bound to the −3425/−3275 region. Based on these results, we conclude that the gender-related expression of the CYP2C12 gene results from the inaccessibility of to STAT5 to the GH-responsive element by chromatin condensation seen in male rat livers, and from the presence of the male-specific HSm that acts as a silencer.
Hypothalamic Growth Hormone-Releasing Hormone (GHRH) Deficiency: Targeted Ablation of GHRH Neurons in Mice Using a Viral Ion Channel Transgene
Authors: Le Tissier Paul R. , Carmignac Danielle F. , Lilley Sarah , Sesay Abdul K. , Phelps Carol J. , Houston Pamela , Mathers Kathleen , Magoulas Charalambos , Ogden David , Robinson Iain C. A. F.
Published: January 2005

Animal and clinical models of GHRH excess suggest that GHRH provides an important trophic drive to pituitary somatotrophs. We have adopted a novel approach to silence or ablate GHRH neurons, using a modified H37A variant of the influenza virus M2 protein (H37AM2). In mammalian cells, H37AM2 forms a high conductance monovalent cation channel that can be blocked by the antiviral drug rimantadine. Transgenic mice with H37AM2 expression targeted to GHRH neurons developed postweaning dwarfism with hypothalamic GHRH transcripts detectable by RT-PCR but not by in situ hybridization and immunocytochemistry, suggesting that expression of H37AM2 had silenced or ablated virtually all the GHRH cells. GHRH-M2 mice showed marked anterior pituitary hypoplasia with GH deficiency, although GH cells were still present. GHRH-M2 mice were also deficient in prolactin but not TSH. Acute iv injections of GHRH in GHRH-M2 mice elicited a significant GH response, whereas injections of GHRP-6 did not. Twice daily injections of GHRH (100 μg/d) for 7 d in GHRH-M2 mice doubled their pituitary GH but not PRL contents. Rimantadine treatment failed to restore growth or pituitary GH contents. Our results show the importance of GHRH neurons for GH and prolactin production and normal growth.
U2AF binding selects for the high conservation of the C. elegans 3′ splice site
Authors: HOLLINS COURTNEY , ZORIO DIEGO A.R. , MACMORRIS MARGARET , BLUMENTHAL THOMAS
Published: January 2005

Caenorhabditis elegans is unusual among animals in having a highly conserved octamer sequence at the 3′ splice site: UUUU CAG/R. This sequence can bind to the essential heterodimeric splicing factor U2AF, with U2AF65 contacting the U tract and U2AF35 contacting the splice site itself (AG/R). Here we demonstrate a strong correspondence between binding to U2AF of RNA oligonucleotides with variant octamer sequences and the frequency with which such variations occur in splice sites. C. elegans U2AF has a strong preference for the octamer sequence and exerts much of the pressure for 3′ splice sites to have the precise UUUUCAG/R sequence. At two positions the splice site has a very strong preference for U even though alternative bases can also bind tightly to U2AF, suggesting that evolution can select against sequences that may have a relatively modest reduction in binding. Although pyrimidines are frequently present at the first base in the exon, U2AF has a very strong bias against them, arguing there is a mechanism to compensate for weakened U2AF binding at this position. Finally, the C in the consensus sequence must remain adjacent to the AG/R rather than to the stretch of U’s, suggesting this C is recognized by U2AF35.
Conserved spacing between the box C/D and C′/D′ RNPs of the archaeal box C/D sRNP complex is required for efficient 2′-O-methylation of target RNAs
Authors: TRAN ELIZABETH , ZHANG XINXIN , LACKEY LELA , MAXWELL E. STUART
Published: January 2005

RNA-guided nucleotide modification complexes direct the post-transcriptional nucleotide modification of both archaeal and eukaryotic RNAs. We have previously demonstrated that efficient 2′-O-methylation activity guided by an in vitro reconstituted archaeal box C/D sRNP requires juxtaposed box C/D and C′/D′ RNP complexes. In these experiments, we investigate the importance of spatially positioning the box C/D and C′/D′ RNPs within the sRNP complex for nucleotide modification. Initial sequence analysis of 245 archaeal box C/D sRNAs from both Eukyarchaeota and Crenarchaeota kingdoms revealed highly conserved spacing between the box C/D and C′/D′ RNA motifs. Distances between boxes C to D′ and C′ to D (D′ and D spacers, respectively) exhibit highly constrained lengths of 12 nucleotides (nt). Methanocaldococcus jannaschii sR8 sRNA, a model box C/D sRNA with D and D′ spacers of 12 nt, was mutated to alter the distance between the two RNA motifs. sRNAs with longer or shorter spacer regions could still form sRNPs by associating with box C/D core proteins, L7, Nop56/58, and fibrillarin, comparable to wild-type sR8. However, these reconstituted box C/D sRNP complexes were severely deficient in methylation activity. Alteration of the D and D′ spacer lengths disrupted the guided methylation activity of both the box C/D and C′/D′ RNP complexes. When only one spacer region was altered, methylation activity of the corresponding RNP was lost. Collectively, these results demonstrate the importance of box C/D and C′/D′ RNP positioning for preservation of critical inter-RNP interactions required for efficient box C/D sRNP-guided nucleotide methylation.
Small molecule control of pre-mRNA splicing
Authors: GRAVELEY BRENTON R.
Published: January 2005

SR proteins regulate alternative splicing by binding to exonic sequences where, via an arginine/serine-rich splicing activation domain, they enhance the binding of the spliceosome to the adjacent splice sites. Here, a system is described in which a nontoxic derivative of the small molecule rapamycin is used to control pre-mRNA splicing in vitro. This involves the rapamycin-dependent recruitment of a splicing activation domain located on one protein to a second protein bound to the pre-mRNA. These results provide a new approach to explore for regulating gene expression in vivo with small molecules by controlling pre-mRNA splicing.
The role of fibroblast growth factors and their receptors in prostate cancer
Authors: Kwabi-Addo B , Ozen M , Ittmann M
Published: January 2005

Prostate cancer is the most common malignancy in men in the USA and the second leading cause of cancer deaths. Fibroblast growth factors (FGFs), including FGF1 (acidic FGF), FGF2 (basic FGF), FGF6 and FGF8 are all expressed at increased levels in prostate cancer as paracrine and/or autocrine growth factors for the prostate cancer cells. In addition, increased mobilization of FGFs from the extracellular matrix in cancer tissues can increase the availability of FGFs to cancer cells. Prostate cancer epithelial cells express all four types of FGF receptors (FGFR-1 to -4) at variable frequencies. Expression of FGFR-1 and FGFR-4 is most closely linked to prostate cancer progression, while the role of FGFR-2 remains controversial. Activation of FGF receptors can activate multiple signal transduction pathways including the phospholipase Cγ, phosphatidyl inositol 3-kinase, mitogen-activated protein kinase and signal transducers and activators of transcription (STAT) pathways, all of which play a role in prostate cancer progression. Sprouty proteins can negatively regulate FGF signal transduction, potentially limiting the impact of FGF signaling in prostate cancer, but in a significant fraction of prostate cancers there is decreased expression of Sprouty1 mRNA and protein. The effects of increased FGF receptor signaling are wide ranging and involve both the cancer cells and surrounding stroma, including the vasculature. The net result of increased FGF signaling includes enhanced proliferation, resistance to cell death, increased motility and invasiveness, increased angiogenesis, enhanced metastasis, resistance to chemotherapy and radiation and androgen independence, all of which can enhance tumor progression and clinical aggressiveness. For this reason, the FGF signaling system it is an attractive therapeutic target, particularly since therapies targeting FGF receptors and/or FGF signaling can affect both the tumor cells directly and tumor angiogenesis. A number of approaches that could target FGF receptors and/or FGF receptor signaling in prostate cancer are currently being developed.
Nutritional modulation of the cell cycle and breast cancer
Authors: Hilakivi-Clarke L , Wang C , Kalil M , Riggins R , Pestell R G
Published: January 2005

In the USA, breast cancer accounts for approximately 30% of all cancers diagnosed in women and is the second leading cause of cancer death in women. An understanding of the molecular genetic events governing breast cancer lead to both prevention and intervention strategies in an attempt to reduce mortality and morbidity from breast cancer. The last three decades of medical research examining the molecular pathogenesis of cancers have provided compelling evidence for the universal disruption of the cell cycle in human tumors. The importance of cell cycle control in human cancer was recognized by the recent award of the Nobel Prize to Drs Nurse and Hartwell for their discovery of the cyclins. More recent studies have demonstrated a critical interface between hormonal signaling and the cell cycle. In parallel, epidemiological studies have identified as being associated with breast cancer important dietary and environmental components that regulate hormonal signaling. This review describes the intersection of these two fields of study, which together imply a role for dietary prevention and intervention in human breast cancer perhaps through altering cell cycle components.
Identification and validation of cell surface antigens for antibody targeting in oncology
Authors: Carter Paul , Smith Leia , Ryan Maureen
Published: January 2005

Recent clinical successes with antibodies have reinvigorated interest in the identification and validation of new antigens for antibody therapy, including cell surface proteins for targeting in oncology, the focus of this review. Target identification commonly involves the search for differences between tumor and non-tumor cell lines and/or tissue at the DNA, mRNA, protein or antibody reactivity levels. The next stage, target validation, utilizes antibodies to profile the expression of antigen in normal and tumor tissue and to verify that the antigen is selectively expressed on the surface of tumor cells. Supportive evidence for protein expression is often sought by mRNA profiling and, sometimes, analysis for genomic defects. Unfortunately, concordance between mRNA and protein levels has been found in only about ~20% of cases and therefore must be evaluated for individual targets of interest. Antigens judged suitable for antibody targeting are then advanced to the next stage, namely, in vitro and then in vivo screening of antibodies for anti-tumor activities. Subsequent optimization of an antibody clinical lead for therapy is a desirable, if not obligatory, step to developing an antibody as an anti-cancer therapeutic. No single approach or even combination of methods has emerged as the preferred way to identify surface antigens suitable for targeting in oncology. Major options at each step in the process are reviewed here, including their strengths and limitations.
Osteoprotegerin and osteopontin serum values in postmenopausal advanced breast cancer patients treated with anastrozole
Authors: Martinetti A , Bajetta E , Ferrari L , Zilembo N , Seregni E , Del Vecchio M , Longarini R , La Torre I , Toffolatti L , Paleari D , Bombardieri E
Published: January 2005

Osteoprotegerin (OPG) is a potent antiresorptive molecule that binds NF-kappaB ligand, the final effector for osteoclastogenesis. OPG production is regulated by a number of cytokines and hormones. Osteopontin (OPN) is a secreted adhesive glycoprotein involved in tumour angiogenesis, and also a non-collagenous protein involved in bone turnover. OPN serum value is associated with tumour burden and survival in advanced breast cancer patients. The short-term effects of anastrozole on OPG and OPN serum values, and the usefulness of these analytes during follow-up were studied in 34 consecutive advanced breast cancer patients receiving anastrozole 1 mg/day. Blood samples were taken before treatment and at 2, 4, 8 and 12 weeks. OPG and OPN values were measured by ELISA. The results were analysed for all patients, and also separately for patients with (group A, 22 patients) and without (group B, 12 patients) bone metastasis. Whether the survival of all patients was related to their OPN serum values was also tested by placing patients into three groups (terciles) according to their baseline OPN values. No significant changes in OPG and OPN values were observed in the complete patient group. There was no difference in baseline OPG and OPN serum values between patients in groups A and B. In group A, a significant percentage increase in both OPG and OPN values from baseline was detected during treatment. No significant changes were reported for group B patients. Furthermore, in group A, a significant increase in both analytes was evident only for patients with progressive disease (PD). The Kaplan–Meier adjusted survival estimates for patients grouped according to tercile OPN values differed significantly (P = 0.001, log rank test). In conclusion, in the short term, anastrozole does not seem to affect OPG and OPN serum values in patients without bone disease. OPG and OPN appear to be useful predictors of the outcome of skeletal disease and elevated OPN values may be associated with short survival in advanced breast cancer patients.
Mechanisms of tamoxifen resistance
Authors: Ring Alistair , Dowsett Mitch
Published: January 2005

The anti-oestrogen tamoxifen is the most commonly used treatment for patients with oestrogen-receptor (ER)-positive breast cancer. Although many patients benefit from tamoxifen in the adjuvant and metastatic settings, resistance is an important clinical problem. The target of tamoxifen in vivo is the ER. Over the last decade many advances have been made in our understanding of the biology of the ER which may help to explain how resistance to tamoxifen develops. Such mechanisms may include changes in the expression of ERα or ERβ, alterations in co-regulatory proteins, and the influences of cellular kinase signal transduction pathways. The experimental and clinical evidence supporting these mechanisms of tamoxifen resistance are discussed in this review.
Growth factor-driven mechanisms associated with resistance to estrogen deprivation in breast cancer: new opportunities for therapy
Authors: Nicholson R I , Staka C , Boyns F , Hutcheson I R , Gee J M W
Published: January 2005

There is an increasing body of evidence demonstrating that elevated growth signaling in breast cancer cells can promote forms of endocrine resistance in either an estrogen receptor-dependent or -independent manner. The current article reviews what is known about such growth factor signaling networks and resistance to estrogen withdrawal and considers the many novel therapeutic opportunities that stem from this knowledge.
The impact of cancer therapy on the endocrine system in survivors of childhood brain tumours
Authors: Gleeson H K , Shalet S M
Published: January 2005

Survival rates are improving following cancer therapy for childhood brain tumours. There is therefore a growing cohort of survivors at risk of late effects of cancer therapy. Endocrine problems are very common in these patients. The recognition and prompt management of these are essential to prevent further morbidity and impairment of quality of life.

Cranial radiation can damage hypothalamic–pituitary function, most frequently affecting GH status; however, higher radiation doses may cause more widespread hypothalamic–pituitary damage. Early puberty secondary to cranial irradiation is now being managed with gonadotrophin-releasing hormone analogues to improve final height. Prompt diagnosis and management of GH deficiency may improve final height outcome; continued GH therapy beyond final height aids the achievement of adult body composition (lean body mass and bone mass) and GH therapy in adulthood improves quality of life. Both cranial irradiation alone and with spinal irradiation can result in radiation damage to the thyroid resulting in hypothyroidism and thyroid nodules, a high proportion of which are malignant. Gonadal damage secondary to spinal irradiation and adjuvant chemotherapy may have long-term consequences including infertility.
Insulin-like growth factor-I receptor signalling and acquired resistance to gefitinib (ZD1839; Iressa) in human breast and prostate cancer cells
Authors: Jones H E , Goddard L , Gee J M W , Hiscox S , Rubini M , Barrow D , Knowlden J M , Williams S , Wakeling A E , Nicholson R I
Published: January 2005

De novo and acquired resistance to the anti-tumour drug gefitinib (ZD1839; Iressa), a specific epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI) has been reported. We have determined whether signalling through the IGF-I receptor (IGF-1R) pathway plays a role in the gefitinib-acquired resistance phenotype. Continuous exposure of EGFR-positive MCF-7-derived tamoxifen resistant breast cancer cells (TAM-R) to 1 μM gefitinib resulted in a sustained growth inhibition (90%) for 4 months before the surviving cells resumed proliferation. A stable gefitinib-resistant subline (TAM/TKI-R) was established after a further 2 months and this showed no detectable basal phosphorylated EGFR activity. Compared with the parental TAM-R cells, the TAM/ TKI-R cells demonstrated (a) elevated levels of activated IGF-1R, AKT and protein kinase C (PKC)δ, (b) an increased sensitivity to growth inhibition by the IGF-1R TKI AG1024 and (c) an increased migratory capacity that was reduced by AG1024 treatment. Similarly, the EGFR-positive androgen-independent human prostate cancer cell line DU145 was also continuously challenged with 1 μM gefitinib and, although substantial growth inhibition (60%) was seen initially, a gefitinib-resistant variant (DU145/TKI-R) developed after 3 months. Like their breast cancer counterparts, the DU145/TKI-R cells showed increases in the levels of components of the IGF-1R signalling pathway and an elevated sensitivity to growth inhibition by AG1024 compared with the parent DU145 cell line. Additionally, DU145/TKI-R cell migration was also decreased by this inhibitor. We have therefore concluded that in breast and prostate cancer cells acquired resistance to gefitinib is associated with increased signalling via the IGF-1R pathway, which also plays a role in the invasive capacity of the gefitinib-resistant phenotype.
Expression of tyrosine kinases in human malignancies as potential targets for kinase-specific inhibitors
Authors: Singer Christian F , Hudelist Gernot , Lamm Wolfgang , Mueller Ruth , Czerwenka Klaus , Kubista Ernst
Published: January 2005

Tyrosine kinase (TK) inhibition has been identified as a promising strategy in the treatment of human malignancies and several synthetic inhibitors have been developed. While the selective blockage of specific TKs is highly effective in vitro, clinical results have been less impressive. It has been suggested that the simultaneous inhibition of multiple TKs might lead to more favorable therapeutic results in vivo. We have therefore performed a systematic analysis of intratumoral TK expression in order to identify potential targets for a simultaneous kinase inhibition. To this end, we have analyzed the protein expression of membrane-associated epidermal growth factor receptor (EGF-R), Her-2/neu, platelet-derived growth factor receptor (PDGF-R), insulin-like growth factor receptor (IGF-R), c-Kit and of cytoplasmatic c-Abl in 500 human tumors of epithelial, stromal and mesenchymal origin by immunohistochemistry, and found a distinct pattern of kinase expression: EGF-R, PDGF-R and c-Abl were expressed in the majority of malignant tumors, whereas c-Kit, Her-2/neu and IGF-R protein expression was considerably less frequent. Overall, the EGF-R protein expression was correlated with PDGF-R, c-Kit and c-Abl immunoreactivity (P = 0.003, P = 0.001 and P < 0.001, respectively). c-Abl was co-expressed with IGF-R and PDGF-R (P = 0.003 and P < 0.001, respectively). Kinase co-expression was also seen in tumor subgroups and was particularly significant in breast cancer where IGF-R protein was expressed together with PDGF-R and c-Abl (P = 0.003 and P = 0.004, respectively), and in colon cancer where PDGF-R was correlated with EGF-R (P < 0.001). With the exception of Her-2/neu expression and age, intra-tumoral TK expression was not associated with parameters such as grading or histological subtypes. Taken together, we have found a specific pattern of kinase co-expression and have identified several potential targets for a tumor-specific multimodal TK inhibition.
Novel roles of the autocrine motility factor/phosphoglucose isomerase in tumor malignancy
Authors: Yanagawa T , Funasaka T , Tsutsumi S , Watanabe H , Raz A
Published: January 2005

Autocrine motility factor (AMF) stimulates cell motility in an autocrine manner and is related to tumor malignancy. AMF is a multifunctional molecule, also known as phosphoglucose isomerase and neuroleukin. Signal cascades of the AMF-stimulated motility and novel functions of this protein contributing to tumor malignancy have been presented recently. AMF stimulation activated small Rho-like GTPases and subsequently induced actin fiber rearrangement, which was removed by the C3 exoenzyme, a specific inhibitor of Rho. The expression of Jun N-terminal kinase (JNK)1, JNK2 and the Rho GDP dissociation inhibitor-β was upregulated by AMF. The addition of AMF to culture medium stimulated the motility of the endothelial cells and the formation of tube-like structures in collagen gels. Highly AMF-expressing HT1080 cells induced aggressive angiogenesis in vivo. The expression of fms-like tyrosine kinase (Flt)-1, a vascular endothelial growth factor (VEGF) receptor, was enhanced in AMF-expressing tumors dependent on protein kinase C and phosphatidylinositol 3 kinase (PI3K) activation; meanwhile kinase insert domain-containing receptor, another receptor of VEGF, was not. Permeability of mesothelial and endothelial cell monolayers was increased by AMF, and numerous gaps were observed in the monolayers after treatment with AMF. AMF gene transfection transformed NIH3T3 cells to proliferate quickly and acquire anti-apoptosis ability induced by serum deprivation in a PI3K-dependent manner. The anti-apoptotic effect of AMF has been described by other authors who have shown that the AMF over-expressing cells were resistant to mitomycin-C-induced apoptosis showing regression of Apaf-1 and caspase-9 dependent on PI3K and MAP kinase. These novel functions of AMF makes it a likely target for cancer therapy.
Comprehensive gene expression profiling of anaplastic thyroid cancers with cDNA microarray of 25 344 genes
Authors: Onda M , Emi M , Yoshida A , Miyamoto S , Akaishi J , Asaka S , Mizutani K , Shimizu K , Nagahama M , Ito K , Tanaka T , Tsunoda T
Published: January 2005

Little is known about the genetic mechanisms of anaplastic thyroid cancer (ATC). This is the most virulent of all human malignancies, and it is believed to result from transformation of differentiated thyroid cancers. To identify a set of genes involved in the development of ATC, we investigated expression profiles of 11 cell lines derived from ATC using a cDNA microarray representing 25 344 genes. Semi-quantitative RT-PCR experiments carried out for some genes that had shown altered expression on the microarray verified frequent over-expression of destrin, HSPA8, stathmin, LDH-A, ATP5A1, PSMB6, B23, HDP-1 and LDH-B, and frequent under-expression of thyroglobulin, PBP and c-FES/FPS genes among the cell lines and also among ten primary ATCs. In addition to mRNA expression studies, up-regulation of GDI2, destrin and stathmin were confirmed with immunohistochemical analysis. The extensive list of genes identified provides valuable information towards understanding the development of ATC, and provides a source of possible biomarkers for diagnosis and/or molecular targets for the development of novel drugs to treat ATC.
Prospective evaluation of estrogen receptor-β in predicting response to neoadjuvant antiestrogen therapy in elderly breast cancer patients
Authors: Cappelletti Vera , Celio Luigi , Bajetta Emilio , Allevi Arianna , Longarini Raffaella , Miodini Patrizia , Villa Raffaella , Fabbri Alessandra , Mariani Luigi , Giovanazzi Riccardo , Galante Emanuele , Greco Marco , Grazia Daidone Maria
Published: January 2005

It has been proposed that knowledge of estrogen receptor β (ER-β) expression may refine estrogen receptor α (ER-α) predictivity of response to endocrine therapy. We challenged this hypothesis in ERα-positive breast cancers subjected to preoperative antiestrogen treatment. Forty-seven elderly (≥65 years old) women with nonmetastatic, ER-α-positive (by immunohistochemistry) primary breast cancers (> 2 cm in diameter) entered a neoadjuvant hormone therapy protocol (60 mg/day toremifene for 3 months). ER-α and ER-β (ERs) mRNA was determined by semiquantitative RT-PCR, before (on core needle biopsy) and after (on surgical specimens) neoadjuvant treatment. Study end points included: (1) relation between treatment response and ER mRNA expression; and (2) changes in ER expression after treatment. The response was clinically assessed as tumor size change at the end of the preoperative treatment. ER mRNA expression was assessable before and after treatment in 38 and 20 cases respectively. ER-β was co-expressed with ER-α at variable levels and significantly correlated only with progesterone receptor (P = 0.0285). Objective clinical response, including patients with minor change (≥25–<50% tumor shrinkage after treatment), was documented in 68.4% of cases and was independent of ER-β levels or changes. ER-α levels were higher in tumors from patients in complete remission than in those from women achieving partial response or minor change compared with non-responsive patients (median expression values: 801 versus 516 versus 320 arbitrary units) and were consistently down-regulated by preoperative treatment. We conclude that in this elderly patient population with ER-α-positive tumors, ER-β mRNA was neither predictive of response to preoperative toremifene nor provided additional information to the knowledge of ER-α mRNA levels, which, conversely, were directly correlated with likelihood of response.
Differential expression of the CCN family members Cyr61, CTGF and Nov in human breast cancer
Authors: Jiang Wen G , Watkins Gareth , Fodstad Oystein , Douglas-Jones Anthony , Mokbel Kefah , Mansel Robert E
Published: January 2005

The CCN family members cysteine-rich 61 (Cyr61/CCN1), connective tissue growth factor (CTGF/CCN2) and nephroblastoma over-expressed (Nov/CCN3) play diverse roles in cells, are known to regulate cell growth, adhesion, matrix production and migration and are involved in endocrine-regulated pathways in various cell types. The role of these molecules in cancer remains controversial. In a cohort of 122 human breast tumours (together with 32 normal breast tissues) we have analysed the expression of all three CCN members at the mRNA and protein levels. Significantly higher levels of Cyr61 (P = 0.02), but low levels of CTGF and Nov, were seen in tumour tissues compared with normal tissues. Significantly raised levels of Cyr61 were associated with poor prognosis (P = 0.02), nodal involvement (P = 0.03) and metastatic disease (P = 0.016). Patients who died of breast cancer also had high levels of Cyr61. In contrast, CTGF in patients with poor prognosis (P = 0.021), metastasis (P = 0.012), local recurrence (P = 0.0024)and mortality (P = 0.0072)had markedly reduced levels. Similar to CTGF, low levels of Nov were also seen in patients with poor prognosis and mortality and with significantly decreased survival (P = 0.033 and P = 0.0146, respectively). This result was fully supported by immunohistochemical analysis of frozen sectioned tissues. While fibroblasts and endothelial cells generally expressed good levels of all three CCN proteins, highly invasive MDA MB 231 cells expressed lower levels of CTGF and Nov, but higher levels of Cyr61, than the less invasive MCF-7. It is concluded that members of the CCN family are differentially expressed and may play important but contrasting roles in the progressive nature of human breast cancer. While Cyr61 appears to act as a factor stimulating aggressiveness, CTGF and Nov may act as tumour suppressors.
Proteasome activity is altered in skeletal muscle tissue of tumour-bearing rats a leucine-rich diet
Authors: Ventrucci G , Mello M A R , Gomes-Marcondes M C C
Published: January 2005

Leucine can modulate skeletal muscle metabolism by enhancing protein synthesis and decreasing proteolysis. In this study, we investigated the effects of leucine on the ubiquitin–proteasome system in skeletal muscle of pregnant tumour-bearing rats fed a leucine-rich diet. Pregnant Wistar rats were distributed into three groups that were fed a semi-purified control diet (C, control; W, Walker tumour-bearing; P, pair-fed) and three other groups of pregnant rats fed a semi-purified leucine-rich diet (L, leucine; WL, Walker tumour-bearing; PL, pair-fed). The tumour-bearing rats were injected subcutaneously with a suspension of Walker 256 tumour cells. Protein synthesis and degradation were measured in gastrocnemius muscle; the total protein content and tissue chymotrypsin-like and alkaline phosphatase enzyme activities were also determined. Muscle protein extracts were run on SDS-PAGE to assess the expression of the myosin heavy chain (MHC), 20S α proteasome subunit, 19S MSSI ATPase regulator subunit and 11S α subunit. Although tumour growth decreased the incorporation of [3H]-Phe, the concomitant feeding of a leucine-rich diet increased the rate of protein synthesis. Muscle proteolysis in both tumour-bearing groups was increased more than in the respective control groups. Conversely, the leucine-rich diet caused less protein breakdown in the WL group than in the W group. Only the W group showed a significant reduction (71%) in the myosin content. In WL rats, the 20S proteasome content (32 kDa band) was reduced, while the expression of the 19S subunit was 3-fold less than in the W group and the 11S proteasome subunit reduced, to around 32% less than in the W group. These findings clearly indicate that leucine can stimulate protein synthesis and inhibit protein breakdown in pregnant rats, probably by modulating the activation of the ubiquitin–proteasome system during tumour growth.
Distinct gene expression profiles in norepinephrine- and epinephrine-producing hereditary and sporadic pheochromocytomas: activation of hypoxia-driven angiogenic pathways in von Hippel–Lindau syndrome
Authors: Eisenhofer G , Huynh T-T , Pacak K , Brouwers F M , Walther M M , Linehan W M , Munson P J , Mannelli M , Goldstein D S , Elkahloun A G
Published: January 2005

Pheochromocytomas in von Hippel–Lindau (VHL) syndrome produce exclusively norepinephrine, whereas those in multiple endocrine neoplasia type 2 (MEN 2) produce epinephrine. This study examined the pathways activated in VHL-associated pheochromocytomas by comparing gene expression profiles in VHL and MEN 2 tumors in relationship to profiles in sporadic norepinephrine- and epinephrine-producing tumors. Larger and more distinct differences in gene expression among hereditary than sporadic tumors indicated the importance of the underlying mutation to gene expression profiles. Many of the genes over-expressed in VHL compared with MEN 2 tumors were clearly linked to the hypoxia-driven angiogenic pathways that are activated in VHL-associated tumorigenesis. Such genes included those for the glucose transporter, vascular endothelial growth factor (VEGF), placental growth factor, angiopoietin 2, tie-1, VEGF receptor 2 and its coreceptor, neuropilin-1. Other up-regulated genes, such as connective tissue growth factor, cysteine-rich 61, matrix metalloproteinase 1, vascular endothelial cadherin, tenascin C, stanniocalcin 1, and cyclooxygenases 1 and 2 are known to be involved in VEGF-regulated angiogenesis. Shared differences in expression of subsets of genes in norepinephrine- versus epinephrine-producing hereditary and sporadic pheochromocytomas indicated other differences in gene expression that may underlie the biochemical phenotype. Over-expression of the hypoxia-inducible transcription factor, HIF-2α, in norepinephrine-predominant sporadic and VHL tumors compared with epinephrine-producing tumors indicates that expression of this gene depends on the noradrenergic biochemical phenotype. The findings fit with the known expression of HIF-2α in norepinephrine-producing cells of the sympathetic nervous system and might explain both the development and noradrenergic biochemical phenotype of pheochromocytomas in VHL syndrome.
BRAF and endocrine tumors: mutations are frequent in papillary thyroid carcinomas, rare in endocrine tumors of the gastrointestinal tract and not detected in other endocrine tumors
Authors: Perren A , Schmid S , Locher T , Saremaslani P , Bonvin C , Heitz P U , Komminoth P
Published: January 2005

The tumorigenesis of sporadic endocrine tumors is still not fully understood. Activating point mutations of the serine/threonine kinase gene BRAF located on 7q34 are found in a wide range of malignancies, with the highest frequency (66%) occurring in malignant melanomas. Melanomas are tumors of neural-crest-derived cells as are medullary thyroid carcinomas, pheochromocytomas and paragangliomas. BRAF has not been examined in endocrine tumors of the diffuse neuroendocrine system or of neural-crest-derived cells.

We examined 130 endocrine tumors of the pancreas, parathyroid gland, adrenal medulla, paraganglia, lung and gastrointestinal tract as well as follicular and c-cell-derived thyroid tumors. We found a high rate of V559E mutations in papillary thyroid carcinomas (47%), one V599E mutation in a well-differentiated gastric endocrine carcinoma (malignant carcinoid), but no activating BRAF mutations in all other endocrine tumors examined. These results point towards different pathways in tumorigenesis of endocrine tumors of various localizations and only rare involvement of the MAP kinase (MAPK) pathway in a subset of malignant neuroendocrine tumors.
Tamoxifen exerts agonistic effects on clusterin and complement C3 gene expression in RUCA-I primary xenografts and metastases but not normal uterus
Authors: Zierau Oliver , O’Sullivan Jacintha , Morrissey Colm , McDonald Dana , Wünsche Winfried , Schneider Martin R , Tenniswood Martin P , Vollmer Günter
Published: January 2005

Tamoxifen is the most widely prescribed anti-neoplastic drug for the treatment of both localized and metastatic breast cancer. It is also the prototype for a class of drugs that are referred to as selective estrogen receptor modifiers (SERMs), most of which have both estrogenic and anti-estrogenic activity in estrogen target tissues including the breast and endometrium. The underlying mechanisms of action of SERMs in the breast and endometrium that lead to profound differences in the tissue-specific effects of tamoxifen have not yet been elucidated.

We have compared the effects of tamoxifen and the pure anti-estrogen ICI 182,780 (Faslodex) in the RUCA-I hormone-responsive rat endometrial cell line in vitro and in vivo. In cell culture, RUCA-I cells responded to both estrogens and anti-estrogens, and the expression of clusterin and complement C3 mRNAs required the presence of estradiol and was repressed in the absence of estradiol or in the presence of the pure anti-estrogen ICI 182,780. Tamoxifen, on the other hand, induced both complement C3 and clusterin mRNA in the absence of estradiol and failed to repress their expression in the presence of estradiol. When grown as subcutaneous xenografts in syngeneic Da/Han rats for 5 weeks, the RUCA-I cells retained their sensitivity to estradiol, as demonstrated by significantly enhanced tumor growth in intact female rats compared with the growth in ovariectomized rats. But neither ICI 182,780 nor tamoxifen had a significant impact on tumor growth in cycling or ovariectomized animals. On the other hand, tamoxifen was potently estrogenic in metastatic lymph nodes, increasing the size of the lymph node tumors almost 6-fold over that seen in the intact cycling animals. In primary tumors, the expression of complement C3 mirrored that seen in vitro, although tamoxifen showed some agonist activity in ovariectomized animals. Tamoxifen also displayed marked agonist activity with respect to clusterin expression and enhanced clusterin mRNA levels and protein in both the primary tumors and lymph metastases in intact and ovariectomized animals.

Given the recent demonstration that over-expression of clusterin increases the metastatic potential of breast cancer cells, these data may provide a mechanistic explanation for the increased incidence of endometrial cancer in postmenopausal patients treated with tamoxifen.
Progesterone receptor A and B expression and progestagen treatment in growth and spread of endometrial cancer cells in nude mice
Authors: Hanekamp Eline E , Kühne Liesbeth M , Grootegoed J Anton , Burger Curt W , Blok Leen J
Published: January 2005

In endometrial cancer, decreased expression of progesterone receptor (PR) isotypes A and B (PRA and PRB) is a feature of poorly differentiated tumours. In distant metastases, PRB is the predominantly expressed isotype and endometrial cancer cells that express PRB have been observed to be more invasive. Furthermore, PRB-associated in vitro invasion is markedly inhibited by progestagens.

In the present study, ovariectomized mice were injected intraperitoneally with Ishikawa endometrial cancer cells that express only PRA, only PRB, both PRA and PRB, or no PR. Half of the mice were substituted with medroxyprogesterone acetate (MPA). After ten weeks, growth and spread of the cancer cells were examined macroscopically, microscopically, and by PCR detection. Without MPA substitution, cells that express only PRB were found to be the most proliferative and migrative, while cells that express only PRA, both receptor isotypes, or no PR, showed minimal growth and spread. MPA appeared to inhibit growth and spread of PR-positive cells. Surprisingly, when mice that were inoculated with PR-negative cells were substituted with MPA, this resulted in massive abdominal tumour growth.

These results provide further evidence that over-expression of PRB in endometrial cancer contributes to the development of a more aggressive phenotype. MPA inhibits tumour growth and spread of PR-positive cells, but can also have an indirectly stimulating effect on PR-negative tumour cells, probably through a host-mediated response.
The TRPS1 transcription factor: androgenic regulation in prostate cancer and high expression in breast cancer
Authors: Chang Glenn T G , Jhamai Mila , van Weerden Wytske M , Jenster Guido , Brinkmann Albert O
Published: January 2005

TRPS1 mRNA is more highly expressed in androgen-dependent lymph node carcinoma of prostate-fast growing colony (LNCaP-FGC) compared with androgen-independent lymph node carcinoma of prostate-lymph node original (LNCaP-LNO) prostate cancer cell lines. Furthermore, TRPS1 mRNA expression is down-regulated by androgens in LNCaP-FGC cells, a process mediated by the androgen receptor (AR). Here, we present TRPS1 protein expression in human prostate cancer material derived from a panel of six androgen-dependent and eight androgen-independent human prostate cancer xenografts. TRPS1 protein is expressed in all androgen-dependent xenografts, which also express AR and prostate-specific antigen (PSA). Androgen withdrawal by castration resulted in an increase in TRPS1 protein in two androgen-dependent xenografts, indicating relieved repression by action of AR. TRPS1 protein is expressed in four androgen-independent xenografts and is low or absent in the other four androgen-independent xenografts. Androgen withdrawal by castration demonstrates that TRPS1 protein levels remain the same in 1 androgen-independent xenograft, most likely due to the lack of AR expression. These data show that TRPS1 protein expression is regulated by androgens via the AR in human prostate cancer xenografts.

Analysis of TRPS1 mRNA expression in normal and tumour tissue of the prostate and 18 other human tissues, showed that TRPS1 had the highest mRNA expression levels in normal and tumour tissues of breast. In addition, high TRPS1 mRNA and protein expression levels were observed in four out of five human breast cancer cell lines.

In conclusion, TRPS1 protein expression is down-regulated by androgens in human prostate cancer, and analysis of TRPS1 mRNA expression levels in several human tissues showed that the highest levels were observed in normal and tumour breast tissue.
Rapid regulation of thyroid sodium–iodide symporter activity by thyrotrophin and iodine
Authors: Ferreira Andrea C F , Lima Lívia P , Araújo Renata L , Müller Glaucia , Rocha Renata P , Rosenthal Doris , Carvalho Denise P
Published: January 2005

Transport of iodide into thyrocytes, a fundamental step in thyroid hormone biosynthesis, depends on the presence of the sodium–iodide symporter (NIS). The importance of the NIS for diagnosis and treatment of diseases has raised several questions about its physiological control. The goal of this study was to evaluate the influence of thyroid iodine content on NIS regulation by thyrotrophin (TSH) in vivo. We showed that 15-min thyroid radioiodine uptake can be a reliable measurement of NIS activity in vivo. The effect of TSH on the NIS was evaluated in rats treated with 1-methyl-2-mercaptoimidazole (MMI; hypothyroid with high serum TSH concentrations) for 21 days, and after 1 (R1d), 2 (R2d), or 5 (R5d) days of withdrawal of MMI. NIS activity was significantly greater in both MMI and R1d rats. In R2d and R5d groups, thyroid iodide uptake returned to normal values, despite continuing high serum TSH, possibly as a result of the re-establishment of iodine organification after withdrawal of MMI. Excess iodine (0.05% NaI for 6 days) promoted a significant reduction in thyroid radioiodide uptake, an effect that was blocked by concomitant administration of MMI, confirming previous findings that iodine organification is essential for the iodide transport blockade seen during iodine overload. Therefore, our data show that modulation of the thyroid NIS by TSH depends primarily on thyroid iodine content and, further, that the regulation of NIS activity is rapid.