bluuebunny/crossref_metadata_2025_split huggingface dataset:
K-Ras Promotes Growth Transformation and Invasion of Immortalized Human Pancreatic Cells by Raf and Phosphatidylinositol 3-Kinase Signaling
Authors: Campbell Paul M. , Groehler Angela L. , Lee Kwang M. , Ouellette Michel M. , Khazak Vladimir , Der Channing J. 
Published: March 2007

Abstract
Mutational activation of the K-Ras oncogene is well established as a key genetic step in the development and growth of pancreatic adenocarcinomas. However, the mechanism by which aberrant Ras signaling promotes uncontrolled pancreatic tumor cell growth remains to be fully elucidated. The recent use of primary human cells to study Ras-mediated oncogenesis provides important model cell systems to dissect this mechanism. We have used a model of telomerase-immortalized human pancreatic duct-derived cells (E6/E7/st) to study mechanisms of Ras growth transformation. First, we found that human papillomavirus E6 and E7 oncogenes, which block the function of the p53 and Rb tumor suppressors, respectively, and SV40 small t antigen were required to allow mutant K-Ras(12D) growth transformation. Second, K-Ras(12D) caused growth transformation in vitro, including enhanced growth rate and loss of density dependency for growth, anchorage independence, and invasion through reconstituted basement membrane proteins, and tumorigenic transformation in vivo. Third, we determined that the Raf, phosphatidylinositol 3-kinase (PI3K), and Ral guanine nucleotide exchange factor effector pathways were activated, although extracellular signal-regulated kinase (ERK) activity was not up-regulated persistently. Finally, pharmacologic inhibition of Raf/mitogen-activated protein kinase/ERK and PI3K signaling impaired K-Ras–induced anchorage-independent growth and invasion. In summary, our studies established, characterized, and validated E6/E7/st cells for the study of Ras-induced oncogenesis. [Cancer Res 2007;67(5):2098–106]
MG-132 Sensitizes TRAIL-Resistant Prostate Cancer Cells by Activating c-Fos/c-Jun Heterodimers and Repressing c-FLIP(L)
Authors: Li Wenhua , Zhang Xiaoping , Olumi Aria F. 
Published: March 2007

Abstract
Tumor necrosis factor–related apoptosis-inducing ligand (TRAIL) is a promising anticancer agent because it induces apoptosis in cancer cells but not in normal cells. Unfortunately, some cancer cells develop resistance to TRAIL-induced apoptosis. Therefore, it is clinically relevant to determine the molecular mechanisms that differentiate between TRAIL-sensitive and TRAIL-resistant tumors. Previously, we have shown that the antiapoptotic molecule cellular-FLICE-inhibitory protein long isoform [c-FLIP(L)] is necessary and sufficient to maintain resistance to TRAIL-induced apoptosis. We have found that c-FLIP(L) is transcriptionally regulated by the activator protein-1 (AP-1) family member protein c-Fos. Here, we report that MG-132, a small-molecule inhibitor of the proteasome, sensitizes TRAIL-resistant prostate cancer cells by inducing c-Fos and repressing c-FLIP(L). c-Fos, which is activated by MG-132, negatively regulates c-FLIP(L) by direct binding to the putative promoter region of the c-FLIP(L) gene. In addition to activating c-Fos, MG-132 activates another AP-1 family member, c-Jun. We show that c-Fos heterodimerizes with c-Jun to repress transcription of c-FLIP(L). Therefore, MG-132 sensitizes TRAIL-resistant prostate cancer cells by activating the AP-1 family members c-Fos and c-Jun, which, in turn, repress the antiapoptotic molecule c-FLIP(L). [Cancer Res 2007;67(5):2247–55]
High Levels of Heat Shock Protein Hsp72 in Cancer Cells Suppress Default Senescence Pathways
Authors: Yaglom Julia A. , Gabai Vladimir L. , Sherman Michael Y. 
Published: March 2007

Abstract
The major heat shock protein Hsp72 is constitutively expressed in many tumor cell lines and biopsies, and its expression correlates with poor prognosis in several types of cancer. Hsp72 was suggested to play an important role in neoplastic transformation and tumor development. We addressed the role of Hsp72 in cancer cells by investigating the consequences of specific depletion of Hsp72 using small interfering RNA. Down-regulation of Hsp72 in certain cancer lines triggered cell senescence associated with activation and stabilization of p53 and induction of the cell cycle inhibitor p21. Effects of Hsp72 depletion on senescence and p53 did not result from a proteotoxic stress, DNA instability, or activation of ataxia-telangiectasia-mutated (ATM) and ATM- and Rad3-related pathways. Instead, depletion of Hsp72 reduced stability and activity of the p53 inhibitor Hdm2. In addition, Hsp72 depletion triggered a p53-independent senescence program through inhibitory phosphorylation and down-regulation of the cell cycle kinase Cdc2. Therefore, Hsp72 provides a selective advantage to cancer cells by suppressing default senescence via p53-dependent and p53-independent pathways. [Cancer Res 2007;67(5):2373–81]
New Soft Alkylating Agents with Enhanced Cytotoxicity against Cancer Cells Resistant to Chemotherapeutics and Hypoxia
Authors: Patenaude Alexandre , Deschesnes Réna G. , Rousseau Jean L.C. , Petitclerc Éric , Lacroix Jacques , Côté Marie-France , C.-Gaudreault René 
Published: March 2007

Abstract
Chloroethylureas (CEU) are soft alkylating agents that covalently bind to β-tubulin (βTAC) and affect microtubule polymerization dynamics. Herein, we report the identification of a CEU subset and its corresponding oxazolines, which induce cell growth inhibition, apoptosis, and microtubule disruption without alkylating β-tubulin (N-βTAC). Both βTAC and N-βTAC trigger the collapse of mitochondrial potential (ΔΨm) and modulate reactive oxygen species levels, following activation of intrinsic caspase-8 and caspase-9. Experiments using human fibrosarcoma HT1080 respiratory-deficient cells (ρ0) and uncoupler of the mitochondrial respiratory chain (MRC) showed that βTAC and N-βTAC impaired the MRC. ρ0 cells displayed an increased sensitivity toward N-βTAC as compared with ρ+ cells but, in contrast, were resistant to βTAC or classic chemotherapeutics, such as paclitaxel. Oxazoline-195 (OXA-195), an N-βTAC derivative, triggered massive swelling of isolated mitochondria. This effect was insensitive to cyclosporin A and to Bcl-2 addition. In contrast, adenine nucleotide translocator (ANT) antagonists, bongkrekic acid or atractyloside, diminished swelling induced by OXA-195. The antiproliferative activities of the N-βTACs CEU-025 and OXA-152 were markedly decreased in the presence of atractyloside. Conversely, pretreatment with cyclosporin A enhanced growth inhibition induced by βTAC and N-βTAC. One of the proteins alkylated by N-βTAC was identified as the voltage-dependent anion channel isoform-1, an ANT partner. Our results suggest that βTAC and N-βTAC, despite their common ability to affect the microtubule network, trigger different cytotoxic mechanisms in cancer cells. The role of mitochondria in these mechanisms and the potential of N-βTAC as a new therapeutic approach for targeting hypoxia-resistant cells are discussed. [Cancer Res 2007;67(5):2306–16]
Stable Overexpression of Smad7 in Human Melanoma Cells Impairs Bone Metastasis
Authors: Javelaud Delphine , Mohammad Khalid S. , McKenna Christopher R. , Fournier Pierrick , Luciani Flavie , Niewolna Maryla , André Jocelyne , Delmas Véronique , Larue Lionel , Guise Theresa A. , Mauviel Alain 
Published: March 2007

Abstract
Melanoma has a propensity to metastasize to bone, where it is exposed to high concentrations of transforming growth factor-β (TGF-β). Because TGF-β promotes bone metastases from other solid tumors, such as breast cancer, we tested the role of TGF-β in melanoma metastases to bone. 1205Lu melanoma cells, stably transfected to overexpress the natural TGF-β/Smad signaling inhibitor Smad7, were studied in an experimental model of bone metastasis whereby tumor cells are inoculated into the left cardiac ventricle of nude mice. All mice bearing parental and mock-transfected 1205Lu cells developed osteolytic bone metastases 5 weeks post-tumor inoculation. Mice bearing 1205Lu-Smad7 tumors had significantly less osteolysis on radiographs and longer survival compared with parental and mock-transfected 1205Lu mice. To determine if the reduced bone metastases observed in mice bearing 1205Lu-Smad7 clones was due to reduced expression of TGF-β target genes known to enhance metastases to bone from breast cancer cells, we analyzed gene expression of osteolytic factors, parathyroid hormone-related protein (PTHrP) and interleukin-11 (IL-11), the chemotactic receptor CXCR4, and osteopontin in 1205Lu cells. Quantitative reverse transcription-PCR analysis indicated that PTHrP, IL-11, CXCR4, and osteopontin mRNA steady-state levels were robustly increased in response to TGF-β and that Smad7 and the TβRI small-molecule inhibitor, SB431542, prevented such induction. In addition, 1205Lu-Smad7 bone metastases expressed significantly lower levels of IL-11, connective tissue growth factor, and PTHrP. These data suggest that TGF-β promotes osteolytic bone metastases due to melanoma by stimulating the expression of prometastatic factors via the Smad pathway. Blockade of TGF-β signaling may be an effective treatment for melanoma metastasis to bone. [Cancer Res 2007;67(5):2317–24]
Histone Deacetylase Inhibitors Synergize p300 Autoacetylation that Regulates Its Transactivation Activity and Complex Formation
Authors: Stiehl Daniel P. , Fath Donna M. , Liang Dongming , Jiang Yubao , Sang Nianli 
Published: March 2007

Abstract
p300/cyclic AMP–responsive element binding protein–binding protein (CBP) are general coactivators for multiple transcription factors involved in various cellular processes. Several highly conserved domains of p300/CBP serve as interacting sites for transcription factors and regulatory proteins. Particularly, the intrinsic histone acetyltransferase (HAT) activity and transactivation domains (TAD) play essential roles for their coactivating function. Autoacetylation of p300/CBP is commonly observed in cell-free HAT assays and has been implicated in the regulation of their HAT activity. Here, we show that six lysine-rich regions in several highly conserved functional domains of p300 are targeted by p300HAT for acetylation in cell-free systems. We show that p300 is susceptible to acetylation in cultured tumor cells and that its acetylation status is affected by histone deacetylase inhibitor trichostatin A. We further show that either treatment with deacetylase inhibitors or coexpression of Gal4-p300HAT, which alone has no transactivation activity, stimulates the activity of the COOH-terminal TAD of p300 (p300C-TAD). We have defined the minimal p300C-TAD and show that it is sufficient to respond to deacetylase inhibitors and is a substrate for p300HAT. Finally, we show that acetylated p300 possesses enhanced ability to interact with p53. Taken together, our data suggest that acetylation regulates p300C-TAD and that acetylation of p300/CBP may contribute to the dynamic regulation of their complex formation with various interacting partners. [Cancer Res 2007;67(5):2256–64]
Epidermal Growth Factor Receptor Mutants from Human Lung Cancers Exhibit Enhanced Catalytic Activity and Increased Sensitivity to Gefitinib
Authors: Mulloy Roseann , Ferrand Audrey , Kim Youngjoo , Sordella Raffaella , Bell Daphne W. , Haber Daniel A. , Anderson Karen S. , Settleman Jeffrey 
Published: March 2007

Abstract
Somatic mutations within the epidermal growth factor receptor (EGFR) kinase domain are detected in 10% to 30% of human non–small cell lung cancers and are correlated with striking clinical responses in a subset of patients treated with EGFR kinase inhibitors, such as gefitinib and erlotinib. Cell-based studies suggest that these mutant EGFRs promote increased autophosphorylating activity on a subset of EGFR COOH-terminal tyrosines and the consequent engagement of a subset of downstream effectors. Because EGFR function is regulated at multiple levels in vivo, and it is therefore difficult to assess the direct consequences of these mutations on EGFR enzyme function, we measured EGFR catalytic activity in in vitro kinase assays using purified recombinant proteins corresponding to the cytoplasmic domain of wild-type and two frequently detected EGFR mutants (DelL747-P753insS and L858R). Both mutants exhibit substantially increased autophosphorylating activity relative to wild-type EGFR, and they exhibit distinct reaction kinetics. In addition, the mutant kinases are more sensitive to kinase inhibition by gefitinib, which seems to reflect their increased drug affinity. These findings suggest that the altered signaling properties and drug sensitivity of these EGFR mutants that have been observed in vivo largely result from differences in the catalytic properties of the kinase. In addition, we find that the T790M secondary “drug resistance mutation” of EGFR, which frequently arises in relapsed patients that initially responded to treatment, confers enhanced kinase activity to primary activating EGFR alleles and may, therefore, be oncogenic in some contexts. [Cancer Res 2007;67(5):2325–30]
Overexpression of Hedgehog Signaling Molecules and Its Involvement in the Proliferation of Endometrial Carcinoma Cells
Authors: Feng Yu-Zhen , Shiozawa Tanri , Miyamoto Tsutomu , Kashima Hiroyasu , Kurai Miyuki , Suzuki Akihisa , Ying-Song Jiang , Konishi Ikuo 
Published: March 2007

Abstract
Purpose: Research has revealed abnormal activation of the hedgehog pathway in human malignancies. The present study was undertaken to examine the expression and functional involvement of the hedgehog pathway in endometrial tissues.
Experimental Design: The expression of sonic hedgehog (Shh), patched (Ptch), Smoothened (Smo), and Gli1 was examined in various endometrial tissues and endometrial carcinoma cell lines. The effect of hedgehog signaling on the proliferation of endometrial carcinoma cell lines was also examined.
Results: The expression of Shh, Ptch, Smo, and Gli1 was very weak in normal endometrium, but was increased in endometrial hyperplasia and carcinoma stepwisely with significant differences. There was no marked difference in the expression of these molecules in carcinomas according to stages and histologic grades. Treatment with cyclopamine, a specific inhibitor of the hedgehog pathway, for endometrial carcinoma Ishikawa and HHUA cells suppressed growth by 56% and 67%, respectively, compared with the control. The addition of recombinant Shh peptide to HHUA cells enhanced their proliferation by 41%. The silencing of Gli1 using small interfering RNA (siGli1) resulted in the growth suppression and down-regulation of Ptch expression. In addition, the cyclopamine/siGli1-induced growth suppression was associated with the down-regulation of cyclins D1 and A and N-myc. No somatic mutations for ptch and smo genes were detected in the endometrial carcinoma cases examined.
Conclusions: The abnormal activation of this pathway is involved in the proliferation of endometrial carcinoma cells possibly in an auto-/paracrine fashion, suggesting the possibility of the hedgehog pathway being a novel candidate for molecular targeting.
Long-term Idiotype Vaccination Combined with Interleukin-12 (IL-12), or IL-12 and Granulocyte Macrophage Colony-Stimulating Factor, in Early-Stage Multiple Myeloma Patients
Authors: Hansson Lotta , Abdalla Amir Osman , Moshfegh Ali , Choudhury Aniruddha , Rabbani Hodjattallah , Nilsson Bo , Osterborg Anders , Mellstedt Håkan 
Published: March 2007

AbstractPurpose and Experimental Design: Twenty-eight patients with immunoglobulin G myeloma stages I to II were immunized i.d. over 110 weeks with autologous M protein combined with interleukin-12 (IL-12; n = 15) or with IL-12 and granulocyte macrophage colony-stimulating factor (GM-CSF; n = 13). Idiotype-specific T-cell responses were assessed by [3H]thymidine incorporation, enzyme-linked immunospot assay, and delayed-type hypersensitivity reaction.Results: Based on these three assays, idiotype-specific immune responses were noted in 5 of 15 (33%) patients in the IL-12 group and in 11 of 13 (85%) patients in the GM-CSF/IL-12 group (P &lt; 0.01). Immune response was seen only in patients with M-component concentration of &lt;50 g/L. Three of 16 (19%) responders showed a gradually increasing idiotype-specific T-cell response, whereas 11 of 16 (69%) patients showed initial response, which then disappeared rapidly; the latter pattern was frequently associated with subsequent progressive disease. Immune nonresponse was associated with an increase in the numbers of CD4+/CD25+ cells (regulatory T cells), which was absent in responding patients. Median time to progression for immune responders (n = 16) was 108 weeks compared with 26 weeks for nonresponders (n = 12; P = 0.03).Conclusions: These results indicate that idiotype immunization of myeloma patients with GM-CSF and IL-12 may induce specific T-cell response more frequently than with IL-12 alone and that immune response may correlate with time to progression and nonresponse with increased numbers of regulatory T cells.
Combined Inhibitory Effects of Green Tea Polyphenols and Selective Cyclooxygenase-2 Inhibitors on the Growth of Human Prostate Cancer Cells Both In vitro and In vivo
Authors: Adhami Vaqar Mustafa , Malik Arshi , Zaman Najia , Sarfaraz Sami , Siddiqui Imtiaz Ahmad , Syed Deeba Nadeem , Afaq Farrukh , Pasha Farrukh Sierre , Saleem Mohammad , Mukhtar Hasan 
Published: March 2007

Abstract
Purpose: Cyclooxygenase-2 (COX-2) inhibitors hold promise for cancer chemoprevention; however, recent toxicity concerns suggest that new strategies are needed. One approach to overcome this limitation is to use lower doses of COX-2 inhibitors in combination with other established agents with complementary mechanisms. In this study, the effect of (−)epigallocatechin-3-gallate (EGCG), a promising chemopreventive agent from green tea, was tested alone and in combination with specific COX-2 inhibitors on the growth of human prostate cancer cells both in vitro and in vivo.
Experimental Design: Human prostate cancer cells LNCaP, PC-3, and CWR22Rν1 were treated with EGCG and NS398 alone and in combination, and their effect on growth and apoptosis was evaluated. In vivo, athymic nude mice implanted with androgen-sensitive CWR22Rν1 cells were given green tea polyphenols (0.1% in drinking water) and celecoxib (5 mg/kg, i.p., daily, 5 days per week), alone and in combination, and their effect on tumor growth was evaluated.
Results: Combination of EGCG (10-40 μmol/L) and NS-398 (10 μmol/L) resulted in enhanced (a) cell growth inhibition; (b) apoptosis induction; (c) expression of Bax, pro-caspase-6, and pro-caspase-9, and poly(ADP)ribose polymerase cleavage; (d) inhibition of peroxisome proliferator activated receptor γ; and (e) inhibition of nuclear factor-κB compared with the additive effects of the two agents alone, suggesting a possible synergism. In vivo, combination treatment with green tea polyphenols and celecoxib resulted in enhanced (a) tumor growth inhibition, (b) lowering of prostate-specific antigen levels, (c) lowering of insulin-like growth factor-I levels, and (d) circulating levels of serum insulin-like growth factor binding protein-3 compared with results of single-agent treatment.
Conclusions: These data suggest synergistic and/or additive effects of combinatorial chemopreventive agents and underscore the need for rational design of human clinical trials.
Approval Summary: Sunitinib for the Treatment of Imatinib Refractory or Intolerant Gastrointestinal Stromal Tumors and Advanced Renal Cell Carcinoma
Authors: Goodman Vicki L. , Rock Edwin P. , Dagher Ramzi , Ramchandani Roshni P. , Abraham Sophia , Gobburu Jogarao V.S. , Booth Brian P. , Verbois S. Leigh , Morse David E. , Liang Cheng Yi , Chidambaram Nallaperumal , Jiang Janet X. , Tang Shenghui , Mahjoob Kooros , Justice Robert , Pazdur Richard 
Published: March 2007

Abstract
Purpose: To describe the Food and Drug Administration (FDA) review and approval of sunitinib malate (Sutent). Sunitinib received regular approval for the treatment of gastrointestinal stromal tumor (GIST) after disease progression or intolerance to imatinib mesylate (Gleevec). Additionally, sunitinib received accelerated approval for the treatment of advanced renal cell carcinoma.
Experimental Design: For the GIST indication, FDA reviewed data from a randomized, placebo-controlled trial with supportive evidence from a single-arm study. For the advanced renal cell carcinoma indication, FDA reviewed data from two single-arm studies of patients with cytokine-refractory metastatic renal cell carcinoma.
Results: In patients with imatinib refractory or intolerant GIST, time-to-tumor progression of sunitinib-treated patients was superior to that of placebo-treated patients. Median time-to-tumor progression of sunitinib-treated patients was 27.3 weeks, compared with 6.4 weeks for placebo-treated patients (P &lt; 0.0001). Partial responses were observed in 6.8% of sunitinib-treated patients. In patients with metastatic renal cell carcinoma, partial responses were observed in 25.5% (95% confidence interval, 17.5, 34.9) and 36.5% (95% confidence interval, 24.7, 49.6) of patients treated with sunitinib. Median response durations were 27.1 and 54 weeks. The most common adverse events attributed to sunitinib included diarrhea, mucositis, skin abnormalities, and altered taste. Reductions in left ventricular ejection fraction and severe hypertension were also more common in sunitinib-treated patients.
Conclusions: On January 26, 2006, the FDA approved sunitinib for the treatment of patients with imatinib refractory or intolerant GIST. Accelerated approval was granted for the treatment of advanced renal cell carcinoma.
Seeing Fearful Body Language Overcomes Attentional Deficits in Patients with Neglect
Authors: Tamietto Marco , Geminiani Giuliano , Genero Rosanna , de Gelder Beatrice 
Published: March 2007

Abstract
Survival depends to some extent on the ability to detect salient signals and prepare an appropriate response even when attention is engaged elsewhere. Fearful body language is a salient signal of imminent danger, easily observable from a distance and indicating to the observer which adaptive action to prepare for. Here we investigated for the first time whether fearful body language modulates the spatial distribution of attention and enhances visual awareness in neurological patients with severe attentional disorders. Patients with visual extinction and hemispatial neglect following right parietal injury have a rightward attentional bias accompanied by loss of awareness for contralesional left stimuli, especially when competing stimuli appear to the right. Three such patients were tested with pictures of fearful, happy, and neutral bodily expressions briefly presented either unilaterally in the left or right visual field, or to both fields simultaneously. On bilateral trials, unattended and task-irrelevant fearful bodily expressions modulated attentional selection and visual awareness. Fearful bodily expressions presented in the contralesional unattended visual field simultaneously with neutral bodies in the ipsilesional field were detected more often than left-side neutral or happy bodies. This demonstrates that despite pathological inattention and parietal damage, emotion and action-related information in fearful body language may be extracted automatically, biasing attentional selection and visual awareness. Our findings open new perspectives on the role of bodily expressions in attentional selection and suggest that a neural network in intact fronto-limbic and visual areas may still mediate reorienting of attention and preparation for action upon perceiving fear in others.