bluuebunny/crossref_metadata_2025 huggingface dataset:
Cyclic AMP Signaling as a Mediator of Vasculogenic Mimicry in Aggressive Human Melanoma Cells In vitro
Authors: Lissitzky Jean-Claude , Parriaux Danielle , Ristorcelli Elodie , Vérine Alain , Lombardo Dominique , Verrando Patrick
Published: January 2009

Aggressive melanoma cells can engage in a process termed vasculogenic mimicry (VM) that reflects the ability of tumor cells to express a multipotent, stem cell–like phenotype. Melanoma cell plasticity contributes to the lack of efficient therapeutic strategies targeting metastatic tumors. This study reveals cyclic AMP as a mediator of VM in vitro. In uveal and cutaneous metastatic aggressive human melanoma cells, an increase in cyclic AMP by forskolin, dibutyryl cyclic AMP, or G protein–coupled receptor (GPCR) ligands such as adrenaline and vasoactive intestinal peptide inhibited VM to different extents. Although chemical modulators of protein kinase A (PKA) had no effect, a specific pharmacologic activator of Exchange protein directly activated by cyclic AMP (Epac) impaired VM. Ras-associated protein-1 (Rap1) activation assays revealed that cyclic AMP–elevating agents induce a PKA-independent activation of Epac/Rap1. Pharmacologic inhibition of extracellular signal-regulated kinase 1/2 (ERK1/2) activity abolished VM. Phosphorylation of ERK1/2 was PKA-independently inhibited by forskolin but not inhibited by Epac/Rap1 signaling, PKA modulation, or GPCR ligands. Furthermore, the forskolin also inhibited phosphatidyl inositol-3-kinase (PI3K)-mediated activation of protein kinase Akt, as monitored by Ser473 phosphorylation. The pharmacologic activation of Epac and GPCR ligands slightly stimulated Akt, a likely concomitant process of VM modulation. Collectively, these data show that forskolin strongly inhibits VM through PKA-independent activation of Epac/Rap1, PKA-, and Epac-independent inactivation of ERK1/2 and inhibition of PI3K/Akt. The data also show that VM inhibition by GPCR ligands involves mainly the Epac/Rap1-activated signal. Thus cyclic AMP inhibits VM through multiple signaling pathways. [Cancer Res 2009;69(3):802–9]
Hyaluronan, CD44, and Emmprin Regulate Lactate Efflux and Membrane Localization of Monocarboxylate Transporters in Human Breast Carcinoma Cells
Authors: Slomiany Mark G. , Grass G. Daniel , Robertson Angela D. , Yang Xiao Y. , Maria Bernard L. , Beeson Craig , Toole Bryan P.
Published: January 2009

Interactions of hyaluronan with CD44 in tumor cells play important cooperative roles in various aspects of malignancy and drug resistance. Emmprin (CD147; basigin) is a cell surface glycoprotein of the immunoglobulin superfamily that is highly up-regulated in malignant cancer cells and stimulates hyaluronan production, as well as several downstream signaling pathways. Emmprin also interacts with various monocarboxylate transporters (MCT). Malignant cancer cells use the glycolytic pathway and require MCTs to efflux lactate that results from glycolysis. Glycolysis and lactate secretion contribute to malignant cell behaviors and drug resistance in tumor cells. In the present study, we find that perturbation of endogenous hyaluronan, using small hyaluronan oligosaccharides, rapidly inhibits lactate efflux from breast carcinoma cells; down-regulation of emmprin, using emmprin small interfering RNA, also results in decreased efflux. In addition, we find that CD44 coimmunoprecipitates with MCT1, MCT4, and emmprin and colocalizes with these proteins at the plasma membrane. Moreover, after treatment of the cells with hyaluronan oligosaccharides, CD44, MCT1, and MCT4 become localized intracellularly whereas emmprin remains at the cell membrane. Together, these data indicate that constitutive interactions among hyaluronan, CD44, and emmprin contribute to regulation of MCT localization and function in the plasma membrane of breast carcinoma cells. [Cancer Res 2009;69(4):1293–301]
Transcriptional Switch of Dormant Tumors to Fast-Growing Angiogenic Phenotype
Authors: Almog Nava , Ma Lili , Raychowdhury Raktima , Schwager Christian , Erber Ralf , Short Sarah , Hlatky Lynn , Vajkoczy Peter , Huber Peter E. , Folkman Judah , Abdollahi Amir
Published: January 2009

Tumor dormancy has important implications for early detection and treatment of cancer. Lack of experimental models and limited clinical accessibility constitute major obstacles to the molecular characterization of dormant tumors. We have developed models in which human tumors remain dormant for a prolonged period of time (>120 days) until they switch to rapid growth and become strongly angiogenic. These angiogenic tumors retain their ability to grow fast once injected in new mice. We hypothesized that dormant tumors undergo a stable genetic reprogramming during their switch to the fast-growing phenotype. Genome-wide transcriptional analysis was done to dissect the molecular mechanisms underlying the switch of dormant breast carcinoma, glioblastoma, osteosarcoma, and liposarcoma tumors. A consensus expression signature distinguishing all four dormant versus switched fast-growing tumors was generated. In alignment with our phenotypic observation, the angiogenesis process was the most significantly affected functional gene category. The switch of dormant tumors was associated with down-regulation of angiogenesis inhibitor thrombospondin and decreased sensitivity of angiogenic tumors to angiostatin. The conversion of dormant tumors to exponentially growing tumors was also correlated with regulation and activation of pathways not hitherto linked to tumor dormancy process, such as endothelial cell–specific molecule-1, 5′-ecto-nucleotidase, tissue inhibitor of metalloproteinase-3, epidermal growth factor receptor, insulin-like growth factor receptor, and phosphatidylinositol 3-kinase signaling. Further, novel dormancy-specific biomarkers such as H2BK and Eph receptor A5 (EphA5) were discovered. EphA5 plasma levels in mice and mRNA levels in tumor specimens of glioma patients correlated with diseases stage. These data will be instrumental in identifying novel early cancer biomarkers and could provide a rationale for development of dormancy-promoting tumor therapy strategies. [Cancer Res 2009;69(3):836–44]
Inhibition of Class I Phosphoinositide 3-Kinase Activity Impairs Proliferation and Triggers Apoptosis in Acute Promyelocytic Leukemia without Affecting Atra-Induced Differentiation
Authors: Billottet Clotilde , Banerjee Lalita , Vanhaesebroeck Bart , Khwaja Asim
Published: January 2009

We have investigated the role of phosphoinositide 3-kinases (PI3Ks) in the in vitro pathophysiology of acute promyelocytic leukemia (APL) and in the response to treatment with all-trans-retinoic-acid (ATRA), utilizing a range of novel inhibitors that target individual or all catalytic class I isoforms of PI3K (p110α, p110β, p110δ, and p110γ). ATRA-induced phosphorylation of the Akt kinase and ribosomal S6 protein in APL cells was sensitive to class I PI3K, and p110β or p110δ inhibitors, and to the mammalian target of rapamycin (mTOR) inhibitor rapamycin. In primary APL, inhibition of p110β or p110δ triggered apoptosis in the absence or presence of ATRA. Class I PI3K inhibition could also reverse ATRA-induced protection of these cells against doxorubicin and arsenic trioxide, correlating with impaired induction of the antiapoptotic MCL-1 protein. The differentiation-inducing effects of ATRA were not dependent on class I PI3K/mTOR. In summary, class I PI3K signaling, mediated by p110β and p110δ, plays an important role in basal and ATRA-induced cell survival mechanisms in APL. Addition of PI3K inhibitors to induction treatment regimens may provide therapeutic benefit. [Cancer Res 2009;69(3):1027–36]
Proteasome Inhibition Blocks Ligand-Induced Dynamic Processing and Internalization of Epidermal Growth Factor Receptor via Altered Receptor Ubiquitination and Phosphorylation
Authors: Kesarwala Aparna H. , Samrakandi Mustapha M. , Piwnica-Worms David
Published: January 2009

Epidermal growth factor (EGF) receptor (EGFR), a member of the EGF superfamily of receptor tyrosine kinases, is a critical regulator of cell growth and an important target for single agent and combination anticancer therapeutics. To further investigate the dynamics of ligand-induced EGFR processing and regulation noninvasively, we developed a chimeric EGFR-firefly luciferase (FLuc) fusion reporter to directly monitor processing of EGFR in real-time. In a stable HeLa cell line expressing the reporter at physiologically relevant levels, bioluminescence imaging continuously monitored reporter dynamics, correlating with the ligand-induced response of endogenous EGFR as determined by Western blot, subcellular localization of an EGFR-green fluorescent protein (GFP) fusion protein, and validated pharmacologic responses. The signaling competency of the reporter was confirmed by gene rescue experiments in EGFR-null cells. Bioluminescence analysis further showed that proteasome inhibition with bortezomib or MG132 attenuated overall ligand-induced degradation of EGFR. In cells expressing EGFR-GFP, pretreatment with proteasome inhibitors trapped essentially all of the receptor at the cell membrane both before and after ligand-induced activation with EGF. Furthermore, proteasome inhibition enhanced receptor ubiquitination in both the basal and ligand-activated states as well as delayed the processing of ligand-activated phosphorylation of the receptor, kinetically correlating with attenuated receptor degradation. These observations point to a potential mechanism for the synergistic therapeutic effects of combination EGFR- and proteasome-targeted therapies. [Cancer Res 2009;69(3):976–83]
p21/Cip1 and p27/Kip1 Are Essential Molecular Targets of Inositol Hexaphosphate for Its Antitumor Efficacy against Prostate Cancer
Authors: Roy Srirupa , Gu Mallikarjuna , Ramasamy Kumaraguruparan , Singh Rana P. , Agarwal Chapla , Siriwardana Sunitha , Sclafani Robert A. , Agarwal Rajesh
Published: January 2009

Inositol hexaphosphate (IP6) causes G1 arrest and increases cyclin-dependent kinase inhibitors p21/Cip1 and p27/Kip1 protein levels in human prostate cancer (PCa) DU145 cells lacking functional p53. However, whether cyclin-dependent kinase inhibitor I induction by IP6 plays any role in its antitumor efficacy is unknown. Herein, we observed that either p21 or p27 knockdown by small interfering RNA has no considerable effect on IP6-induced G1 arrest, growth inhibition, and death in DU145 cells; however, the simultaneous knockdown of both p21 and p27 reversed the effects of IP6. To further confirm these findings both in vitro and in vivo, we generated DU145 cell variants with knockdown levels of p21 (DU-p21), p27 (DU-p27), or both (DU-p21+p27) via retroviral transduction of respective short hairpin RNAs. Knocking down p21 or p27 individually did not alter IP6-caused cell growth inhibition and G1 arrest; however, their simultaneous ablation completely reversed the effects of IP6. In tumor xenograft studies, IP6 (2% w/v, in drinking water) caused a comparable reduction in tumor volume (40–46%) and tumor cell proliferation (26–28%) in DU-EV (control), DU-p21, and DU-p27 tumors but lost most of its effect in DU-p21+p27 tumors. IP6-caused apoptosis also occurred in a Cip/Kip-dependent manner because DU-p21+p27 cells were completely resistant to IP6-induced apoptosis both in cell culture and xenograft. Together, these results provide evidence, for the first time, of the critical role of p21 and p27 in mediating the anticancer efficacy of IP6, and suggest their redundant role in the antiproliferative and proapoptotic effects of IP6 in p53-lacking human PCa cells, both in vitro and in vivo. [Cancer Res 2009;69(3):1166–73]
Akt Activation Synergizes with Trp53 Loss in Oral Epithelium to Produce a Novel Mouse Model for Head and Neck Squamous Cell Carcinoma
Authors: Moral Marta , Segrelles Carmen , Lara M. Fernanda , Martínez-Cruz Ana Belén , Lorz Corina , Santos Mirentxu , García-Escudero Ramón , Lu Jerry , Kiguchi Kaoru , Buitrago Agueda , Costa Clotilde , Saiz Cristina , Rodriguez-Peralto Jose L. , Martinez-Tello Francisco J. , Rodriguez-Pinilla Maria , Sanchez-Cespedes Montserrat , Garín Marina , Grande Teresa , Bravo Ana , DiGiovanni John , Paramio Jesús M.
Published: January 2009

Head and neck squamous cell carcinoma (HNSCC) is a common human neoplasia with poor prognosis and survival that frequently displays Akt overactivation. Here we show that mice displaying constitutive Akt activity (myrAkt) in combination with Trp53 loss in stratified epithelia develop oral cavity tumors that phenocopy human HNSCC. The myrAkt mice develop oral lesions, making it a possible model of human oral dysplasia. The malignant conversion of these lesions, which is hampered due to the induction of premature senescence, is achieved by the subsequent ablation of Trp53 gene in the same cells in vivo. Importantly, mouse oral tumors can be followed by in vivo imaging, show metastatic spreading to regional lymph nodes, and display activation of nuclear factor-κB and signal transducer and activator of transcription-3 pathways and decreased transforming growth factor-β type II receptor expression, thus resembling human counterparts. In addition, malignant conversion is associated with increased number of putative tumor stem cells. These data identify activation of Akt and p53 loss as a major mechanism of oral tumorigenesis in vivo and suggest that blocking these signaling pathways could have therapeutic implications for the management of HNSCC. [Cancer Res 2009;69(3):1099–108]
Retinoblastoma Tumor Suppressor Gene Expression Determines the Response to Sequential Flavopiridol and Doxorubicin Treatment in Small-Cell Lung Carcinoma
Authors: Budak-Alpdogan Tulin , Chen Bobin , Warrier Anjali , Medina Daniel J. , Moore Dirk , Bertino Joseph R.
Published: January 2009

Purpose: Small-cell lung cancers (SCLC) are defective in many regulatory mechanisms that control cell cycle progression, i.e., functional retinoblastoma protein (pRb). Flavopiridol inhibits proliferation and induces apoptosis in SCLC cell lines. We hypothesized that the sequence flavopiridol followed by doxorubicin would be synergistic in pRb-deficient SCLC cells.

Experimental Design: A H69 pRb-deficient SCLC cell line, H865, with functional pRb and H865 pRb small interfering RNA (siRNA) knockdown cells were used for in vitro and in vivo experiments. The in vivo efficiencies of various sequential combinations were tested using nude/nude athymic mice and human SCLC xenograft models.

Results: Flavopiridol then doxorubicin sequential treatment was synergistic in the pRB-negative H69 cell line. By knocking down pRb with specific siRNA, H865 clones with complete pRb knockdown became sensitive to flavopiridol and doxorubicin combinations. pRb-deficient SCLC cell lines were highly sensitive to flavopiridol-induced apoptosis. pRb-positive H865 cells arrested in G0-G1 with flavopiridol exposure, whereas doxorubicin and all flavopiridol/doxorubicin combinations caused a G2-M block. In contrast, pRb-negative SCLC cells did not arrest in G0-G1 with flavopiridol exposure. Flavopiridol treatment alone did not have an in vivo antitumor effect, but sequential flavopiridol followed by doxorubicin treatment provided tumor growth control and a survival advantage in Rb-negative xenograft models, compared with the other sequential treatments.

Conclusions: Flavopiridol and doxorubicin sequential treatment induces potent in vitro and in vivo synergism in pRb-negative SCLC cells and should be clinically tested in tumors lacking functional pRB.
Inhibition of Poly(ADP-Ribose) Polymerase-1 Enhances Temozolomide and Topotecan Activity against Childhood Neuroblastoma
Authors: Daniel Rachel A. , Rozanska Agata L. , Thomas Huw D. , Mulligan Evan A. , Drew Yvette , Castelbuono Deborah J. , Hostomsky Zdenek , Plummer E. Ruth , Boddy Alan V. , Tweddle Deborah A. , Curtin Nicola J. , Clifford Steven C.
Published: January 2009

Purpose: High-risk neuroblastoma is characterized by poor survival rates, and the development of improved therapeutic approaches is a priority. Temozolomide and topotecan show promising clinical activity against neuroblastoma. Poly(ADP-ribose) polymerase-1 (PARP-1) promotes DNA repair and cell survival following genotoxic insult; we postulated that its inhibition may enhance the efficacy of these DNA-damaging drugs in pediatric cancers.

Experimental Design: We evaluated the chemosensitizing properties of the PARP inhibitor AG014699 (Pfizer, Inc.) in combination with temozolomide and topotecan, against human neuroblastoma cells and xenografts, alongside associated pharmacologic and toxicologic indices.

Results: Addition of PARP-inhibitory concentrations of AG014699 significantly potentiated growth inhibition by both topotecan (1.5- to 2.3-fold) and temozolomide (3- to 10-fold) in vitro, with equivalent effects confirmed in clonogenic assays. In two independent in vivo models (NB1691 and SHSY5Y xenografts), temozolomide caused a xenograft growth delay, which was enhanced by co-administration of AG014699, and resulted in complete and sustained tumor regression in the majority (6 of 10; 60%) of cases. Evidence of enhanced growth delay by topotecan/AG014699 co-administration was observed in NB1691 xenografts. AG014699 metabolites distributed rapidly into the plasma (Cmax, 1.2-1.9 nmol/L at 30 min) and accumulated in xenograft tissues (Cmax, 1-2 μmol/L at 120 min), associated with a sustained suppression of PARP-1 enzyme activity. Doses of AG014699 required for potentiation were not toxic per se.

Conclusions: These data show enhancement of temozolomide and topotecan efficacy by PARP inhibition in neuroblastoma. Coupled with the acceptable pharmacokinetic, pharmacodynamic, and toxicity profiles of AG014699, our findings provide strong rationale for investigation of PARP inhibitors in pediatric early clinical studies.
Vorinostat and bortezomib exert synergistic antiproliferative and proapoptotic effects in colon cancer cell models
Authors: Pitts Todd M. , Morrow Mark , Kaufman Sara A. , Tentler John J. , Eckhardt S. Gail
Published: January 2009

Despite the availability of several Food and Drug Administration-approved drugs, advanced inoperable colorectal cancer remains incurable. In this study, we focused on the development of combined molecular targeted therapies against colon cancer by testing the efficacy of the combination of the histone deacetylase inhibitor vorinostat with the proteasome inhibitor bortezomib to determine if this resulted in synergistic antitumor effects against colorectal cancer. The effects of the histone deacetylase inhibitor vorinostat in combination with the proteasome inhibitor bortezomib on the growth of two colorectal cancer cell lines were assessed with regard to proliferation, cell cycle arrest, and apoptosis. Treatment with the combination of vorinostat and bortezomib resulted in a synergistic decrease in proliferation of both colorectal cancer cell lines compared with treatment with single agents alone. This inhibition was associated with a synergistic increase in apoptosis as measured by caspase-3/7 activity and cleaved poly(ADP-ribose) polymerase. In addition, we observed an increase in the proapoptotic protein BIM and in the number of cells arrested in the G2-M phase of the cell cycle. Although p21 levels were significantly increased, short hairpin RNA knockdown of p21 did not lead to changes in proliferation in response to the combination of drugs, indicating that although p21 is a target of these drugs, it is not required to mediate their antiproliferative effects. These data indicate that combination treatment with vorinostat and bortezomib result in synergistic antiproliferative and proapoptotic effects against colon cancer cell lines, providing a rational basis for the clinical use of this combination for the treatment of colorectal cancer. [Mol Cancer Ther 2009;8(2):342–9]
WIF1, a Wnt pathway inhibitor, regulates SKP2 and c-myc expression leading to G1 arrest and growth inhibition of human invasive urinary bladder cancer cells
Authors: Tang Yaxiong , Simoneau Anne R. , Liao Wu-xiang , Yi Guo , Hope Christopher , Liu Feng , Li Shunqiang , Xie Jun , Holcombe Randall F. , Jurnak Frances A. , Mercola Dan , Hoang Bang H. , Zi Xiaolin
Published: January 2009

Epigenetic silencing of secreted wingless-type (Wnt) antagonists through hypermethylation is associated with tobacco smoking and with invasive bladder cancer. The secreted Wnt inhibitory factor-1 (WIF1) has shown consistent growth-inhibitory effect on various cancer cell lines. Therefore, we assessed the mechanisms of action of WIF1 by either restoring WIF1 expression in invasive bladder cancer cell lines (T24 and TSU-PR1) or using a recombinant protein containing functional WIF1 domain. Both ectopic expression of WIF1 and treatment with WIF1 domain protein resulted in cell growth inhibition via G1 arrest. The G1 arrest induced by WIF1 is associated with down-regulation of SKP2 and c-myc and up-regulation of p21/WAF1 and p27/Kip1. Conversely, reexpression of SKP2 in WIF1-overexpressing TSU-PR1 cells attenuated the WIF1-induced G1 arrest. Furthermore, inhibition of nuclear Wnt signaling by either dominant-negative LEF1 or short hairpin RNA of TCF4 also reduced SKP2 expression. The human SKP2 gene contains two TCF/LEF1 consensus binding sites within the promoter. Chromatin immunoprecipitation/real-time PCR analysis revealed that both WIF1 and dominant-negative LEF1 expression decreased the in vivo binding of TCF4 and β-catenin to the SKP2 promoter. Together, our results suggest that mechanisms of WIF1-induced G1 arrest include (a) SKP2 down-regulation leading to p27/Kip1 accumulation and (b) c-myc down-regulation releasing p21/WAF1 transcription. Additionally, we show that WIF1 inhibits in vivo bladder tumor growth in nude mice. These observations suggest a mechanism for transformation of bladder epithelium on loss of WIF1 function and provide new targets such as SKP2 for intervention in WIF1-deficient bladder cancer. [Mol Cancer Ther 2009;8(2):458–68]
Discovery of Ixabepilone
Authors: Hunt John T.
Published: January 2009

The discovery of the antineoplastic agent paclitaxel and its unique activity as a microtubule-stabilizing agent resulted in dramatic improvements in the treatment of breast, ovarian, and non-small cell lung cancers. Despite the potent antitumor activity of taxanes such as paclitaxel, efficacy of these agents has been limited by development of taxane-resistant tumors in patients. This review describes, with some historical context, our successful efforts to discover a next-generation microtubule-stabilizing agent for the treatment of cancer. In collaboration with the Gesellschaft für Biotechnologische Forschung, we evaluated the epothilones, originally isolated from the myxobacterium Sorangium cellulosum, as potential anticancer agents. Experiments performed at Bristol-Myers Squibb confirmed the ability of these agents to induce tubulin polymerization, cell cycle arrest, and apoptosis. Epothilones A and B showed potent cytotoxic activity toward paclitaxel-sensitive and paclitaxel-resistant cells expressing P-glycoprotein or mutant tubulin. Because the parent epothilones were subject to inactivation via esterase cleavage, we used semisynthetic approaches to prepare analogues without this liability. BMS-247550 (ixabepilone), the lactam analogue of epothilone B, showed increased metabolic stability, potent tubulin polymerization activity, and retained activity against paclitaxel-resistant lines. Based on its shown efficacy in clinical trials, ixabepilone was approved by the Food and Drug Administration in 2007 for treatment of drug-resistant/refractory metastatic or locally advanced breast cancer. [Mol Cancer Ther 2009;8(2):275–81]
REV1 Is Implicated in the Development of Carcinogen-Induced Lung Cancer
Authors: Dumstorf Chad A. , Mukhopadhyay Suparna , Krishnan Elangovan , Haribabu Bodduluri , McGregor W. Glenn
Published: January 2009

The somatic mutation hypothesis of cancer predicts that reducing the frequency of mutations induced by carcinogens will reduce the incidence of cancer. To examine this, we developed an antimutator strategy based on the manipulation of the level of a protein required for mutagenic bypass of DNA damage induced by the ubiquitous carcinogen benzo[a]pyrene. The expression of this protein, REV1, was reduced in mouse cells using a vector encoding a gene-specific targeting ribozyme. In the latter cells, mutagenesis induced by the activated form of benzo[a]pyrene was reduced by >90%. To examine if REV1 transcripts could be lowered in vivo, the plasmid was complexed with polyethyleneimine, a nonviral cationic polymer, and delivered to the lung via aerosol. The endogenous REV1 transcript in the bronchial epithelium as determined by quantitative real-time PCR in laser capture microdissected cells was reduced by 60%. There was a significant decrease in the multiplicity of carcinogen-induced lung tumors from 6.4 to 3.7 tumors per mouse. Additionally, REV1 inhibition completely abolished tumor formation in 27% of the carcinogen-exposed mice. These data support the central role of the translesion synthesis pathway in the development of lung cancer. Further, the selective modulation of members of this pathway presents novel potential targets for cancer prevention. The somatic mutation hypothesis of cancer predicts that the frequency of cancers will also be reduced. (Mol Cancer Res 2009;7(2):247–54)
High Prevalence of Preinvasive Lesions Adjacent to BRCA1/2-Associated Breast Cancers
Authors: Arun Banu , Vogel Kristen J. , Lopez Adriana , Hernandez Mike , Atchley Deann , Broglio Kristine R. , Amos Christopher I. , Meric-Bernstam Funda , Kuerer Henry , Hortobagyi Gabriel N. , Albarracin Constance T.
Published: January 2009

Mutations in BRCA1 and BRCA2 increase a woman's lifetime risk of developing breast cancer by 43% to 84%. It was originally postulated that BRCA1/2-associated breast cancers develop more rapidly than sporadic cancers and may lack preinvasive lesions. More recent studies have found preinvasive lesions in prophylactic mastectomy specimens from mutation carriers; however, there is little information on the presence of preinvasive lesions in tissue adjacent to breast cancers. Our aim is to investigate the role of preinvasive lesions in BRCA-associated breast carcinogenesis.

We retrospectively compared BRCA1/2-associated breast cancers and sporadic breast cancers for the prevalence of preinvasive lesions [ductal carcinoma in situ (DCIS), lobular carcinoma in situ, and atypical lobular hyperplasia] in tissue adjacent to invasive breast cancers.

Pathology was reviewed for 73 BRCA1/2-associated tumors from patients with breast cancer. We selected 146 patients with mutation-negative breast cancer as age-matched controls. Among the BRCA1/2-associated breast cancers, 59% had at least one associated preinvasive lesion compared with 75% of controls. Preinvasive lesions were more prevalent in BRCA2 mutation carriers than in BRCA1 mutation carriers (70% versus 52%, respectively). The most common preinvasive lesion in both groups was DCIS; 56% of BRCA1/2-associated breast cancers and 71% of the sporadic breast cancers had adjacent intraductal disease, respectively.

Preinvasive lesions, most notably DCIS, are common in BRCA1/2-associated breast cancers. These findings suggest that BRCA1/2-associated breast cancers progress through the same intermediate steps as sporadic breast cancers, and that DCIS should be considered as a part of the BRCA1/2 tumor spectrum.
Identification of Modulated Genes by Three Classes of Chemopreventive Agents at Preneoplastic Stages in a p53-Null Mouse Mammary Tumor Model
Authors: Abba Martín C. , Hu Yuhui , Levy Carla C. , Gaddis Sally , Kittrell Frances S. , Hill Jamal , Bissonnette Reid P. , Brown Powel H. , Medina Daniel , Aldaz C. Marcelo
Published: January 2009

Genetically engineered mouse cancer models are among the most useful tools for testing the in vivo effectiveness of the various chemopreventive approaches. The p53-null mouse model of mammary carcinogenesis was previously characterized by us at the cellular, molecular, and pathologic levels. In a companion article, Medina et al. analyzed the efficacy of bexarotene, gefitinib, and celecoxib as chemopreventive agents in the same model. Here we report the global gene expression effects on mammary epithelium of such compounds, analyzing the data in light of their effectiveness as chemopreventive agents. SAGE was used to profile the transcriptome of p53-null mammary epithelium obtained from mice treated with each compound versus controls. This information was also compared with SAGE data from p53-null mouse mammary tumors. Gene expression changes induced by the chemopreventive treatments revealed a common core of 87 affected genes across treatments (P < 0.05). The effective compounds, bexarotene and gefitinib, may exert their chemopreventive activity, at least in part, by affecting a set of 34 genes related to specific cellular pathways. The gene expression signature revealed various genes previously described to be associated with breast cancer, such as the activator protein-1 complex member Fos-like antigen 2 (Fosl2), early growth response 1 (Egr1), gelsolin (Gsn), and tumor protein translationally controlled 1 (Tpt1), among others. The concerted modulation of many of these transcripts before malignant transformation seems to be conducive to predominantly decrease cell proliferation. This study has revealed candidate key pathways that can be experimentally tested in the same model system and may constitute novel targets for future translational research.
Prevention of Tumorigenesis in p53-Null Mammary Epithelium by Rexinoid Bexarotene, Tyrosine Kinase Inhibitor Gefitinib, and Celecoxib
Authors: Medina Daniel , Kittrell Frances , Hill Jamal , Zhang Yun , Hilsenbeck Susan G. , Bissonette Reid , Brown Powel H.
Published: January 2009

The chemopreventive effects of three agents, rexinoid bexarotene, tyrosine kinase inhibitor gefitinib, and celecoxib, were tested on mammary tumor development arising in p53-null mammary epithelium. The rexinoid bexarotene was the most efficacious inhibitor as it reduced mammary tumor development by 75% in virgin mice and significantly delayed mean tumor development by 98 days in hormone-stimulated mice. The tyrosine kinase inhibitor gefitinib reduced mammary tumor incidence by 50% in virgin mice but did not significantly delay mean tumor latency in hormone-stimulated mice. Celecoxib did not reduce tumor incidence or mean tumor latency in either of the two models. The high doses of the rexinoid and the tyrosine kinase inhibitor did not affect the progression of tumors arising from the premalignant mammary outgrowth line, PN8a. A comparison of these agents with tamoxifen shows the superiority of tamoxifen in preventing tumor development in p53-null mammary cells. Similarly, a comparison of the results of the p53 model with other transgenic models in their response to the chemopreventive agents showed that mammary tumors arising from different oncogenic events will respond differently to the different agents.
Screening for Oral Precancer with Noninvasive Genetic Cytology
Authors: Bremmer Jantine F. , Graveland A. Peggy , Brink Arjen , Braakhuis Boudewijn J.M. , Kuik Dirk J. , Leemans C. René , Bloemena Elisabeth , van der Waal Isaäc , Brakenhoff Ruud H.
Published: January 2009

Oral squamous cell carcinomas develop in precancerous fields consisting of genetically altered mucosal epithelial cells. These precancerous fields may appear as clinically visible lesions, in particular, oral leukoplakia, but the large majority remains clinically undetectable. The aim of this study was to assess the potential value of a noninvasive screening approach to detect precancerous fields. As a first step, we developed a suitable assay and investigated 25 leukoplakia patients and 20 noncancer control subjects. Exfoliated cells were removed by a brush from multiple small areas of the oral mucosa, including the leukoplakia. Brushed samples were investigated for allelic imbalance (AI) at chromosomes 3p, 9p, 11q, and 17p using microsatellite markers known to show frequent alterations in oral precancer. AI was absent in all (137) of the samples of the 20 control subjects, yielding a specificity of 100%. AI was detected in exfoliated cell samples of 40% (10 of 25) of the leukoplakia lesions studied. Genetic changes were also found outside the leukoplakia lesions. Most frequent was AI at 9p (9 of 10). The noninvasive assay was validated against the biopsy results of the leukoplakia lesions yielding an estimate of sensitivity of 78% (7 of 9) and a positive predictive value of 100% (7 of 7). Altogether, these results show the feasibility of a noninvasive genetic screening approach for the detection and monitoring of oral precancer. This assay could therefore contribute to the secondary prevention of oral squamous cell carcinoma. The assay also shows promise for the detection of precancerous changes that are not macroscopically visible.
Quality of Life and Psychological Problems of Patients with Oral Mucosal Disease in Dermatological Practice
Authors: Tabolli S. , Bergamo F. , Alessandroni L. , Di Pietro C. , Sampogna F. , Abeni D.
Published: January 2009

Background: Dermatologists see patients with oral mucosal conditions. Objectives: To evaluate oral health-related quality of life (OHRQoL) and the burden of disease of dermatological patients with oral mucosal diseases. Methods: All consecutive patients (April 2005 to November 2006) coming to the oral health care unit of the IDI-IRCCS in Rome were asked to complete oral health-specific (14-item Oral Health Impact Profile, OHIP-14), generic health status (12-item Short Form of Medical Outcome Study, SF-12) and general psychological (12-item General Health Questionnaire, GHQ-12) questionnaires. Physicians and patients gave a global assessment of severity of disease on a 5-point scale. Results: 206 patients participated. Recurrent aphthous stomatitis (RAS) had the highest impact on OHRQoL. Women had poorer OHRQoL both on physical and mental scales of the SF-12. 33.7% of patients were GHQ-positive with women showing a much higher prevalence than men (39.7 vs. 20.3%). OHIP-14 high scores were observed in RAS, followed by oral lichen planus and burning mouth syndrome. Patients whose condition was ‘underestimated’ by the physicians had the worst OHRQoL and psychological status. Conclusions: Administration of specific and generic questionnaires provides a detailed picture of the impact of oral diseases on patients, which adds information that may be useful in clinical practice. The possible contribution of such tools should be assessed in a randomized controlled trial.
Repigmentation by Outer-Root-Sheath-Derived Melanocytes: Proof of Concept in Vitiligo and Leucoderma
Authors: Vanscheidt Wolfgang , Hunziker Thomas
Published: January 2009

Background: Treatment of depigmented skin is an unmet medical need. Objective: Melanocytes or stem cells thereof residing in the outer root sheath (ORS) of hair follicles might be used to repigment skin. Methods: After de-epidermisation, autologous ORS cell solutions were applied to 5 patients with vitiligo and 1 with leucoderma. Results: Stable repigmentation in a variable percentage was documented in all the patients. Conclusion: Applying ORS-derived melanocytes is a promising technology to improve autologous melanocyte transplantation.
Body Mass Index and Body Composition in Adolescents Treated with Gonadotropin-Releasing Hormone Analogue Triptorelin Depot for Central Precocious Puberty: Data at Near Final Height
Authors: Chiocca Elena , Dati Eleonora , Baroncelli Giampiero I. , Mora Stefano , Parrini Donatella , Erba Paola , Bertelloni Silvano
Published: January 2009

Background/Aim: In children with central precocious puberty (CPP), gonadotropin-releasing hormone (GnRH) analogue treatment has been associated with an increase in body mass index (BMI). We evaluated BMI and body composition in adolescents treated with GnRH analogue at their near final height to assess the long-term effects of therapy on these parameters. Patients and Methods: We studied 20 patients (14.8 ± 1.6 years; 17 females) previously treated with triptorelin depot for CPP (3.75 mg/28 days) from 8.1 ± 0.8 to 11.5 ± 0.8 years. 23 healthy adolescents with normal onset of puberty (14.7 ± 2.1 years, 19 females) were the controls. BMI and body composition (dual-energy x-ray absorptiometry) were assessed. Results: Patients reached their near adult height (–0.5 ± 1.1 standard deviation score (SDS)); the girls were menstruating and the majority (15/17) had regular cycles, the boys showed normal testicular function. BMI was unchanged from the start of GnRH analogue therapy (0.4 ± 1.0 SDS) to near adult height (0.2 ± 1.0 SDS, p = NS vs. 0). Total fat mass (TFM) was significantly increased (16,144 ± 8,065 g; controls 10,712.1 ± 4,120.4 g, p < 0.02); glucose homeostasis and lipid profile corresponded to reference ranges. Conclusions: GnRH analogue therapy did not show long-term detrimental effects on BMI, but it may increase TFM, suggesting that body composition should be monitored till adulthood.
The Effect of Reporting Methods for Dosing Times on the Estimation of Pharmacokinetic Parameters of Escitalopram
Authors: Jin Yuyan , Pollock Bruce G. , Frank Ellen , Florian Jeff , Kirshner Margaret , Fagiolini Andrea , Kupfer David J. , Gastonguay Marc R. , Kepple Gail , Feng Yan , Bies Robert R.
Published: January 2009

The objective of this study was to compare population pharmacokinetic models of escitalopram developed from dosage times recorded by a medication event monitoring system (MEMS) versus the reported times from patients with diagnosed depression. Seventy‐three patients were prescribed doses of 10, 15, or 20 mg escitalopram daily. Sparse blood samples were collected at weeks 4, 12, 24, and 36 with 185 blood samples obtained from the 73 patients. NONMEM was used to develop a population pharmacokinetic model based on dosing records obtained from MEMS prior to each blood sample time. A separate population pharmacokinetic analysis using NONMEM was performed for the same population using the patient‐reported last dosing time and assuming a steady‐state condition as the model input. Objective function values and goodness‐of‐fit plots were used as model selection criteria. The absolute mean difference in the last dosing time between MEMS and patient‐reported times was 4.48 ± 10.12 hours. A 1‐compartment model with first‐order absorption and elimination was sufficient for describing the data. Estimated oral clearance (CL/F) to escitalopram was statistically insensitive to reported dosing methods (MEMS vs patient reported: 25.5 [7.0%] vs 26.9 [6.6%] L/h). However, different dosing report methods resulted in significantly different estimates on the volume of distribution (V/F; MEMS vs patient reported: 1000 [17.3%] vs 767 [17.5%] L) and the absorption rate constant Ka (MEMS vs patient reported: 0.74 [45.7%] vs 0.51 [35.4%] h−1) for escitalopram. Furthermore, the parameters estimated from the MEMS method were similar to literature reported values for V/F (∼1100 L) and Ka (∼0.8–0.9 h−1) arising from traditional pharmacokinetic approaches.
A Regulatory Science Perspective on Warfarin Therapy: A Pharmacogenetic Opportunity
Authors: Kim Myong‐Jin , Huang Shiew‐Mei , Meyer Urs A. , Rahman Atiqur , Lesko Lawrence J.
Published: January 2009

Warfarin is a challenging drug to accurately dose, both initially and for maintenance, because of its narrow therapeutic range, wide interpatient variability, and long list of factors that can influence dosing. Two million people in the United States are initiated on warfarin therapy annually, and this number is steadily increasing because of the increase in number of eligible patients. Recently, warfarin was reported to be the fourth leading cause of adverse events. The U.S. Food and Drug Administration recognizes that the adverse event rate of warfarin can be improved through better initial dosing, because many of the serious adverse events of warfarin occur soon after starting treatment. A substantial number of studies demonstrate that common variants of two genes, VKORC1 and CYP2C9, along with other nongenetic factors, correlate significantly with warfarin dosing. The genotypes of VKORC1 and CYP2C9 alone account for nearly 3 times more of the variability (∼30%) in warfarin dosing than do age, weight, gender, and other clinical factors combined (∼12%). Therefore, the purpose of this report is to review the current recommendations for warfarin therapy that involve genetic testing.
Lopinavir/Ritonavir Pharmacokinetics in a Substitution of High‐Dose Soft‐Gelatin Capsule to Tablet Formulation
Authors: Hull Mark W. , Harris Marianne , Lima Viviane , Guillemi Silvia , Harrigan P. Richard , Montaner Julio S. G.
Published: January 2009

Guidelines recommend that when soft‐gelatin capsules of lopinavir/ritonavir are co‐administered with CYP3A4‐inducing agents, doses should be increased to 4 capsules (533 mg/133 mg) twice daily. No evidence is available to guide dosing of lopinavir/ritonavir in tablet formulation in this setting. A single‐center study is conducted to compare the pharmacokinetics of high‐dose lopinavir/ritonavir in 34 patients on stable HAART regimens including 4 soft‐gelatin capsules twice daily who then switch to 3 tablets (600 mg/150 mg) twice daily. Median Cmin on soft‐gelatin capsule and tablets is 4700 ng/mL (interquartile range [IQR] 2310, 6000 ng/mL) and 5640 ng/mL (IQR 4290, 8080 ng/mL), respectively, for those on inducing agents (n = 17). For patients not on inducing agents (n = 17), median Cmin on soft‐gelatin capsule and tablets is 5170 ng/mL (IQR 3640, 6210 ng/mL) and 5640 ng/mL (IQR 4290, 8080 ng/mL), respectively. Among treatment‐experienced patients on lopinavir/ritonavir capsules 533/133 mg twice daily, a switch to tablets 600/150 mg twice daily produces comparable pharmacokinetics, regardless of whether they receive concomitant CYP3A4‐inducing antiretroviral agents.
Population Pharmacokinetic Modeling of Ustekinumab, a Human Monoclonal Antibody Targeting IL‐12/23p40, in Patients With Moderate to Severe Plaque Psoriasis
Authors: Zhu Yaowei , Hu Chuanpu , Lu Ming , Liao Sam , Marini Joseph C. , Yohrling Jennifer , Yeilding Newman , Davis Hugh M. , Zhou Honghui
Published: January 2009

The population pharmacokinetics of ustekinumab are characterized in patients with moderate to severe plaque psoriasis in 2 Phase 3 studies (PHOENIX 1 and PHOENIX 2). Serum concentration data from 1937 patients are analyzed to determine pharmacokinetic characteristics of ustekinumab and to assess factors that may contribute to their variability. The population typical mean (percentage relative standard error) values for apparent clearance, apparent volume of distribution, and absorption rate constant from the final covariate model are 0.465 L·day−1 (2.0%), 15.7 L (2.0%), and 0.354 day−1 (16.2%), respectively. The interindividual variabilities for apparent clearance and apparent volume of distribution are 41.0% and 33.2%, respectively. Of the factors evaluated in this analysis, body weight, diabetes, and positive immune response (antibodies to ustekinumab) are important covariates affecting the apparent clearance and/or apparent volume of distribution of ustekinumab. To fully understand the clinical relevance of these results, the covariate findings need to be evaluated concurrently with the efficacy and safety data.
Ghrelin Does Not Predict Adaptive Hyperphagia in Patients With Short Bowel Syndrome
Authors: Compher Charlene W. , Kinosian Bruce P. , Metz David C.
Published: January 2009

Background: Adaptive hyperphagia is associated with reduced dependence on parenteral nutrition in patients with short bowel syndrome, but mechanisms have not been described. Ghrelin (GHR) has orexigenic effects, whereas peptide YY (PYY) reduces intake. GHR also acts as a hormone to control body fat stores. The authors evaluated whether GHR or PYY was related to caloric intake or absorption in patients with short bowel syndrome and whether GHR was associated with body mass index. Methods: Patients were admitted twice for nutrient balance. Height and body weight were obtained using standardized protocols. Energy intake >40 kcal/kg/day was defined as adaptive hyperphagia. Fasting plasma PYY and GHR were assayed in duplicate with Linco enzyme‐linked immunosorbent assay kits. Results: The median age of the 7 study participants was 62 (range, 45‐66) years, time with short bowel syndrome was 6.6 (range, 2‐29) years, and body mass index was 21.2 kg/m2 (range, 19‐27.7). Five patients had adaptive hyperphagia. Neither GHR nor PYY was significantly related to energy intake or absorption (GHR: R = 0.22 and R = –0.233, PYY: R = 0.10 and R = –0.13). Body mass index trended toward an inverse association with GHR (GHR: R = –0.540, P = .211). Conclusion: The rigorous adaptive hyperphagia seen in these patients with short bowel syndrome was not related to fasting GHR or PYY, suggesting the need to explore other mechanisms.
Nurse Faculty Perceptions of Simulation Use in Nursing Education
Authors: Akhtar-Danesh Noori , Baxter Pamela , Valaitis Ruta K. , Stanyon Wendy , Sproul Susan
Published: January 2009

In this study nursing faculty perceptions of the implementation of simulation in schools of nursing across Ontario, Canada, were explored using the Q-methodology technique. Following Q-methodology guidelines, 104 statements were collected from faculty and students with exposure to simulation to determine the concourse (what people say about the issue). The statements were classified into six domains, including teaching and learning, access/reach, communication, technical features, technology set-up and training, and comfort/ease of use with technology. They were then refined into 43 final statements for the Q-sample. Next, 28 faculty from 17 nursing schools participated in the Q-sorting process. A by-person factor analysis of the Q-sort was conducted to identify groups of participants with similar viewpoints. Results revealed four major viewpoints held by faculty including: (a) Positive Enthusiasts, (b) Traditionalists, (c) Help Seekers, and (d) Supporters. In conclusion, simulation was perceived to be an important element in nursing education. Overall, there was a belief that clinical simulation requires (a) additional support in terms of the time required to engage in teaching using this modality, (b) additional human resources to support its use, and (c) other types of support such as a repository of clinical simulations to reduce the time from development of a scenario to implementation. Few negative voices were heard. It was evident that with correct support (human resources) and training, many faculty members would embrace clinical simulation because it could support and enhance nursing education.
Corresponding Affections: Emotional Exchange Among Siblings in the Nassau Family
Authors: Broomhall Susan , Van Gent Jacqueline
Published: January 2009

This article examines the nature of emotional exchange among the siblings who were the children of William the Silent, the leader of the nascent Dutch Republic. Using evidence from extensive familial correspondence, it asks how the language of emotions could constitute forms of power within the family, by analyzing how actions and expressions of emotion were presented, discussed, and interpreted in epistolary form, to whom, and with what intention and impact. The article studies social, geographic, linguistic, and other distinctions between siblings in their use of affective discourses in correspondence and argues that attention to affective language can help to elucidate the agentive force of emotions in both reflecting and informing notions of power within the family.