bluuebunny/crossref_metadata_2025 huggingface dataset:
Identification of a Metalloprotease-Chemokine Signaling System in the Ovarian Cancer Microenvironment: Implications for Antiangiogenic Therapy
Authors: Agarwal Anika , Tressel Sarah L. , Kaimal Rajani , Balla Marianthi , Lam Francis H. , Covic Lidija , Kuliopulos Athan
Published: June 2010

Ovarian cancer is a lethal gynecologic malignancy that may benefit from new therapies that block key paracrine pathways involved in tumor-stromal interactions and tumor vascularity. It was recently shown that matrix metalloprotease-1 (MMP1) activation of the G protein–coupled receptor protease-activated receptor-1 (PAR1) is an important stimulator of angiogenesis and metastasis in peritoneal mouse models of ovarian cancer. In the present study, we tested the hypothesis that MMP1-PAR1 promotes angiogenesis through its paracrine control of angiogenic chemokine receptors. We found that MMP1-PAR1 activation induces the secretion of several angiogenic factors from ovarian carcinoma cells, most prominently interleukin (IL)-8, growth-regulated oncogene-α (GRO-α), and monocyte chemoattractant protein-1. The secreted IL-8 and GRO-α acts on endothelial CXCR1/2 receptors in a paracrine manner to cause robust endothelial cell proliferation, tube formation, and migration. A cell-penetrating pepducin, X1/2pal-i3, which targets the conserved third intracellular loop of both CXCR1 and CXCR2 receptors, significantly inhibited endothelial cell proliferation, tube formation, angiogenesis, and ovarian tumor growth in mice. Matrigel plugs mixed with MMP1-stimulated, OVCAR-4–conditioned media showed a dramatic 33-fold increase in blood vessel formation in mice. The X1/2pal-i3 pepducin completely inhibited MMP1-dependent angiogenesis compared with a negative control pepducin or vehicle. Conversely, a vascular endothelial growth factor–directed antibody, Avastin, suppressed angiogenesis in mice but, as expected, was unable to inhibit IL-8 and GRO-α–dependent endothelial tube formation in vitro. These studies identify a critical MMP1-PAR1-CXCR1/2 paracrine pathway that might be therapeutically targeted for ovarian cancer treatment. Cancer Res; 70(14); 5880–90. ©2010 AACR.
Mitogen-Activated Protein/Extracellular Signal-Regulated Kinase Kinase 1act/Tubulin Interaction Is an Important Determinant of Mitotic Stability in Cultured HT1080 Human Fibrosarcoma Cells
Authors: Cao Jia-ning , Shafee Norazizah , Vickery Larry , Kaluz Stefan , Ru Ning , Stanbridge Eric J.
Published: June 2010

Activation of the mitogen-activated protein kinase (MAPK) pathway plays a major role in neoplastic cell transformation. Using a proteomics approach, we identified α tubulin and β tubulin as proteins that interact with activated MAP/extracellular signal-regulated kinase kinase 1 (MEK1), a central MAPK regulatory kinase. Confocal analysis revealed spatiotemporal control of MEK1-tubulin colocalization that was most prominent in the mitotic spindle apparatus in variant HT1080 human fibrosarcoma cells. Peptide arrays identified the critical role of positively charged amino acids R108, R113, R160, and K157 on the surface of MEK1 for tubulin interaction. Overexpression of activated MEK1 caused defects in spindle arrangement, chromosome segregation, and ploidy. In contrast, chromosome polyploidy was reduced in the presence of an activated MEK1 mutant (R108A, R113A) that disrupted interactions with tubulin. Our findings indicate the importance of signaling by activated MEK1-tubulin in spindle organization and chromosomal instability. Cancer Res; 70(14); 6004–14. ©2010 AACR.
Inhibition of the Sodium-Potassium-Chloride Cotransporter Isoform-1 Reduces Glioma Invasion
Authors: Haas Brian R. , Sontheimer Harald
Published: June 2010

Malignant gliomas metastasize throughout the brain by infiltrative cell migration into peritumoral areas. Invading cells undergo profound changes in cell shape and volume as they navigate extracellular spaces along blood vessels and white matter tracts. Volume changes are aided by the concerted release of osmotically active ions, most notably K+ and Cl−. Their efflux through ion channels along with obligated water causes rapid cell shrinkage. Suitable ionic gradients must be established and maintained through the activity of ion transport systems. Here, we show that the Sodium-Potassium-Chloride Cotransporter Isoform-1 (NKCC1) provides the major pathway for Cl− accumulation in glioma cells. NKCC1 localizes to the leading edge of invading processes, and pharmacologic inhibition using the loop diuretic bumetanide inhibits in vitro Transwell migration by 25% to 50%. Short hairpin RNA knockdowns of NKCC1 yielded a similar inhibition and a loss of bumetanide-sensitive cell volume regulation. A loss of NKCC1 function did not affect cell motility in two-dimensional assays lacking spatial constraints but manifested only when cells had to undergo volume changes during migration. Intracranial implantation of human gliomas into severe combined immunodeficient mice showed a marked reduction in cell invasion when NKCC1 function was disrupted genetically or by twice daily injection of the Food and Drug Administration–approved NKCC1 inhibitor Bumex. These data support the consideration of Bumex as adjuvant therapy for patients with high-grade gliomas. Cancer Res; 70(13); 5597–606. ©2010 AACR.
Premetastatic Lung “Niche”: Is Vascular Endothelial Growth Factor Receptor 1 Activation Required?
Authors: Duda Dan G. , Jain Rakesh K.
Published: June 2010

Inflammatory pathways may mediate preparation of the “metastatic soil” in the lungs. Some of these pathways—activation and/or the recruitment of certain inflammatory cells—might depend on vascular endothelial growth factor receptor 1 (VEGFR1) activity. Thus, blocking the activity of VEGFR1 (or the interaction with its ligands) has emerged as a potential antimetastasis strategy to target not only angiogenesis and cancer cell survival and migration, but also the recruitment of tumor growth–promoting bone marrow–derived cells (BMDC). However, inhibition of VEGFR1 activity by blocking antibodies or by genetic deletion of the tyrosine kinase domain neither prevented nor changed the rate of spontaneous metastasis formation after surgical removal of primary tumors. Thus, development of VEGFR1-targeted agents should be pursued in selected tumors (e.g., by identifying cancers that depend on VEGFR1 signaling for survival) or in specific combination therapies. Preventing metastasis will likely require identification and blockade of additional or alternative proinflammatory pathways that mediate the priming of the metastatic soil and the growth of micrometastases. Cancer Res; 70(14); 5670–3. ©2010 AACR.
Synthetic Lethality through Combined Notch–Epidermal Growth Factor Receptor Pathway Inhibition in Basal-Like Breast Cancer
Authors: Dong Yiyu , Li Aimin , Wang Jianbo , Weber Jason D. , Michel Loren S.
Published: June 2010

Basal-like breast cancers (BLBC) are highly aggressive, yet selective therapies targeting the specific oncoproteins driving these tumors have not been developed. These cancers frequently express epidermal growth factor receptor (EGFR), with resistance to its inhibition being well documented, albeit poorly understood. Notch pathway activation is also common in this breast cancer subtype and can be suppressed by γ-secretase inhibitors, which effectively block receptor cleavage and activation. Herein, we show that although inhibition of either EGFR or Notch signaling alone is insufficient to suppress basal-like breast tumor cell survival and proliferation, simultaneous inhibition uncovers a synthetic lethal relationship between these two oncogenic pathways. This lethality is due in part to significant decreases in AKT activation caused by combined EGFR and Notch inhibition. Expression of the activated form of Notch1 restores AKT activity and enables cells to overcome cell death after dual-pathway blockade. Combined pathway inhibition is also dramatically more effective at suppressing tumor growth in mice than blocking EGFR or Notch signaling alone. Thus, we show that Notch pathway activation contributes to resistance to EGFR inhibition, and provide a novel treatment strategy for BLBCs. Cancer Res; 70(13); 5465–74. ©2010 AACR.
Low Ascorbate Levels Are Associated with Increased Hypoxia-Inducible Factor-1 Activity and an Aggressive Tumor Phenotype in Endometrial Cancer
Authors: Kuiper Caroline , Molenaar Ilona G.M. , Dachs Gabi U. , Currie Margaret J. , Sykes Peter H. , Vissers Margreet C.M.
Published: June 2010

Activation of the transcription factor hypoxia-inducible factor (HIF)-1 allows solid tumors to thrive under conditions of metabolic stress. Because HIF-1 is switched off by hydroxylation reactions that require ascorbate, inadequate intracellular ascorbate levels could contribute to HIF-1 overactivation. In this study, we investigated whether the ascorbate content of human endometrial tumors [known to be driven by HIF-1 and vascular endothelial growth factor (VEGF)] influenced HIF-1 activity and tumor pathology. We measured protein levels of HIF-1α and three downstream gene products [glucose transporter 1 (GLUT-1), Bcl-2/adenovirus E1B 19 kDa interacting protein 3 (BNIP3), and VEGF], as well as the ascorbate content of tumor and patient-matched normal endometrial tissue samples. HIF-1α and its downstream gene products were upregulated in tumor tissue, with the highest levels being present in high-grade tumors. High-grade tumors also had reduced capacity to accumulate ascorbate compared with normal tissue; however, all grades contained tumors with low ascorbate content. Tumors with the highest HIF-1α protein content were ascorbate deficient. Low ascorbate levels were also associated with elevated VEGF, GLUT-1, and BNIP3 protein levels and with increased tumor size, and there was a significant association between low tissue ascorbate levels and increased activation of the HIF-1 pathway (P = 0.007). In contrast, tumors with high ascorbate levels had lesser levels of HIF-1 activation. This study shows for the first time a likely in vivo relationship between ascorbate and HIF-1, with low tumor tissue ascorbate levels being associated with high HIF-1 activation and tumor growth. Cancer Res; 70(14); 5749–58. ©2010 AACR.
Increased Expression of α6 Integrin in Endothelial Cells Unveils a Proangiogenic Role for Basement Membrane
Authors: Primo Luca , Seano Giorgio , Roca Cristina , Maione Federica , Gagliardi Paolo Armando , Sessa Roberto , Martinelli Marianna , Giraudo Enrico , di Blasio Laura , Bussolino Federico
Published: June 2010

The integrin α6 subunit is part of the α6β1 and α6β4 integrin complexes, which are known to be receptors for laminins and to mediate several biological activities such as embryogenesis, organogenesis, and invasion of carcinoma cells. However, the precise role of α6 integrin in angiogenesis has not yet been addressed. We observed that both vascular endothelial growth factor-A and fibroblast growth factor-2 strongly upregulate α6 integrin in human endothelial cells. Moreover, α6 integrin was positively modulated in angiogenic vessels in pancreatic neuroendocrine carcinoma. In this transgenic mouse model of spontaneous tumorigenesis, α6 integrin expression increased in the angiogenic stage, while being expressed at low levels in normal and hyperplastic tissue. We studied the functional role of α6 integrin during angiogenesis by lentivirus-mediated gene silencing and blocking antibody. Cell migration and morphogenesis on basement membrane extracts, a laminin-rich matrix, was reduced in endothelial cells expressing low levels of α6 integrin. However, we did not observe any differences in collagen matrices. Similar results were obtained in the aortic ring angiogenesis assay. α6 integrin was required for vessel sprouting on basement membrane gels but not on collagen gels, as shown by stably silencing this integrin in the murine aorta. Finally, a neutralizing anti-α6 integrin antibody inhibited in vivo angiogenesis in chicken chorioallantoic membrane and transgenic tumor mouse model. In summary, we showed that the α6 integrin participated in vascular endothelial growth factor-A and fibroblast growth factor-2–driven angiogenesis in vitro and in vivo, suggesting that it might be an attractive target for therapeutic approaches in angiogenesis-dependent diseases such as tumor growth. Cancer Res; 70(14); 5759–69. ©2010 AACR.
Potential for Targeting the Fibroblast Growth Factor Receptors in Breast Cancer
Authors: Hynes Nancy E. , Dey Julien H.
Published: June 2010

Breast cancer is the most common cancer of women, accounting yearly for approximately 30% of newly diagnosed cases and ranking second as a cause of death. Despite improvements in breast cancer detection and development of new therapeutic approaches, there are still tumors for which no targeted therapies are available. This review summarizes recent findings on the fibroblast growth factor receptors (FGFR) and the data supporting their role in breast cancer. We will describe the approaches being made to develop therapeutics targeting these receptors. Finally, to improve the chances for success with FGFR signal transduction inhibitors, strategies to choose appropriate breast cancer patients for treatment will be discussed. Cancer Res; 70(13); 5199–202. ©2010 AACR.
Epigenetic Inactivation of the Potential Tumor Suppressor Gene FOXF1 in Breast Cancer
Authors: Lo Pang-Kuo , Lee Ji Shin , Liang Xiaohui , Han Liangfeng , Mori Tsuyoshi , Fackler Mary Jo , Sadik Helen , Argani Pedram , Pandita Tej K. , Sukumar Saraswati
Published: June 2010

The expression of several members of the FOX gene family is known to be altered in a variety of cancers. We show that in breast cancer, FOXF1 gene is a target of epigenetic inactivation and that its gene product exhibits tumor-suppressive properties. Loss or downregulation of FOXF1 expression is associated with FOXF1 promoter hypermethylation in breast cancer cell lines and in invasive ductal carcinomas. Methylation of FOXF1 in invasive ductal carcinoma (37.6% of 117 cases) correlated with high tumor grade. Pharmacologic unmasking of epigenetic silencing in breast cancer cells restored FOXF1 expression. Re-expression of FOXF1 in breast cancer cells with epigenetically silenced FOXF1 genes led to G1 arrest concurrent with or without apoptosis to suppress both in vitro cell growth and in vivo tumor formation. FOXF1-induced G1 arrest resulted from a blockage at G1-S transition of the cell cycle through inhibition of the CDK2-RB-E2F cascade. Small interfering RNA–mediated depletion of FOXF1 in breast cancer cells led to increased DNA re-replication, suggesting that FOXF1 is required for maintaining the stringency of DNA replication and genomic stability. Furthermore, expression profiling of cell cycle regulatory genes showed that abrogation of FOXF1 function resulted in increased expression of E2F-induced genes involved in promoting the progression of S and G2 phases. Therefore, our studies have identified FOXF1 as a potential tumor suppressor gene that is epigenetically silenced in breast cancer, which plays an essential role in regulating cell cycle progression to maintain genomic stability. Cancer Res; 70(14); 6047–58. ©2010 AACR.
Induction of Anti-Glioma Natural Killer Cell Response following Multiple Low-Dose Intracerebral CpG Therapy
Authors: Alizadeh Darya , Zhang Leying , Brown Christine E. , Farrukh Omar , Jensen Michael C. , Badie Behnam
Published: June 2010

Purpose: Stimulation of toll-like receptor-9 by CpG oligodeoxynucleotides (CpG-ODN) has been shown to counteract the immunosuppressive microenvironment and to inhibit tumor growth in glioma models. These studies, however, have used high doses of CpG-ODN, which can induce toxicity in a clinical setting. The goal of this study was to evaluate the antitumor efficacy of multiple low-dose intratumoral CpG-ODN in a glioma model.

Experimental Design: Mice bearing 4-day-old intracranial GL261 gliomas received a single or multiple (two or four) intratumoral injections of CpG-ODN (3 μg) every 4 days. Tumor growth was measured by bioluminescent imaging, brain histology, and animal survival. Flow cytometry and cytotoxicity assays were used to assess anti-glioma immune response.

Results: Two and four intracranial injections of low-dose CpG-ODN, but not a single injection, eradicated gliomas in 70% of mice. Moreover, surviving animals exhibited durable tumor-free remission (> 3 months) and were protected from intracranial rechallenge with GL261 gliomas, showing the capacity for long-term antitumor immunity. Although most inflammatory cells seemed to increase, activated natural killer (NK) cells (i.e., NK+CD107a+) were more frequent than CD8+CD107a+ in the brains of rechallenged CpG-ODN–treated animals and showed a stronger in vitro cytotoxicity against GL261 target cells. Leukocyte depletion studies confirmed that NK cells played an important role in the initial CpG-ODN antitumor response, but both CD8 and NK cells were equally important in long-term immunity against gliomas.

Conclusions: These findings suggest that multiple low-dose intratumoral injections of CpG-ODN can eradicate intracranial gliomas possibly through mechanisms involving NK-mediated effector function. Clin Cancer Res; 16(13); 3399–408. ©2010 AACR.
Diverse Associations betweenESR1Polymorphism and Breast Cancer Development and Progression
Authors: Ding Shian-ling , Yu Jyh-Cherng , Chen Shou-Tung , Hsu Giu-Cheng , Hsu Huan-Ming , Ho Jar Yi , Lin Yu Hsin , Chang Chien-Ching , Fann Cathy S.J. , Cheng Chun-Wen , Wu Pei-Ei , Shen Chen-Yang
Published: June 2010

Purpose: To test the hypothesis that polymorphisms of ESR1, the gene encoding estrogen receptor α (ERα), are associated with susceptibility, clinical phenotype, and progression of breast cancer.

Patients and Methods: A case-control study was done on 940 patients with incident breast cancer and 1,547 healthy female controls. Fifteen single-nucleotide polymorphisms (SNP) selected from chr6:152,170,379-152,466,100 (exons 1–8 of the ESR1 gene, excluding flanking sequences), reflecting major polymorphisms of this gene, were genotyped. Frequencies of SNPs were compared between cases and controls to identify SNPs associated with cancer susceptibility and between cases with different clinical phenotypes to determine the role of ESR1 polymorphism in cancer progression.

Results: SNPs located in one cluster in intron 1 and one haplotype, based on these SNPs, showed a significant association with breast cancer susceptibility. The tumorigenic contribution of these intron 1 SNPs was more obvious in combination with reproductive risk factors (P for interaction <0.05). One of these intron 1 SNPs was also significantly associated with low ERα expression in tumors. Interestingly, the same intron 1 SNPs showed a correlation with worse clinical phenotypes, including poor differentiation of tumor cells and a late stage. These intron 1 SNPs also showed a significant association with the 5-year breast cancer–specific survival rate of patients, but had opposite effects in ERα-negative and ERα-positive early-stage patients.

Conclusions: Our findings provide support for diverse roles of ESR1 polymorphism in determining susceptibility in different stages of breast cancer. The differences between the important ESR1 SNPs identified in Chinese women in this study and those identified in studies on Western women with breast cancer suggest different roles of ERα in these two populations. Clin Cancer Res; 16(13); 3473–84. ©2010 AACR.
Development of a Multiplexed Tumor-Associated Autoantibody-Based Blood Test for the Detection of Non–Small Cell Lung Cancer
Authors: Farlow Erin C. , Patel Kalpa , Basu Sanjib , Lee Bao-Shiang , Kim Anthony W. , Coon John S. , Faber L. Penfield , Bonomi Philip , Liptay Michael J. , Borgia Jeffrey A.
Published: June 2010

Purpose: Non–small cell lung cancer (NSCLC) has an overall 5-year survival of <15%; however, the 5-year survival for stage I disease is over 50%. Unfortunately, 75% of NSCLC is diagnosed at an advanced stage not amenable to surgery. A convenient serum assay capable of unambiguously identifying patients with NSCLC may provide an ideal diagnostic measure to complement computed tomography–based screening protocols.

Experimental Design: Standard immunoproteomic method was used to assess differences in circulating autoantibodies among lung adenocarcinoma patients relative to cancer-free controls. Candidate autoantibodies identified by these discovery phase studies were translated into Luminex-based “direct-capture” immunobead assays along with 10 autoantigens with previously reported diagnostic value. These assays were then used to evaluate a second patient cohort composed of four discrete populations, including: 117 NSCLC (81 T1-2N0M0 and 36 T1-2N1-2M0), 30 chronic obstructive pulmonary disorder (COPD)/asthma, 13 nonmalignant lung nodule, and 31 “normal” controls. Multivariate statistical methods were then used to identify the optimal combination of biomarkers for classifying patient disease status and develop a convenient algorithm for this purpose.

Results: Our immunoproteomic-based biomarker discovery efforts yielded 16 autoantibodies differentially expressed in NSCLC versus control serum. Thirteen of the 25 analytes tested showed statistical significance (Mann-Whitney P < 0.05 and a receiver operator characteristic “area under the curve” over 0.65) when evaluated against a second patient cohort. Multivariate statistical analyses identified a six-biomarker panel with only a 7% misclassification rate.

Conclusions: We developed a six-autoantibody algorithm for detecting cases of NSCLC among several high-risk populations. Population-based validation studies are now required to assign the true value of this tool for identifying early-stage NSCLC. Clin Cancer Res; 16(13); 3452–62. ©2010 AACR.
A Distinct Spectrum of Copy Number Aberrations in Pediatric High-Grade Gliomas
Authors: Bax Dorine A. , Mackay Alan , Little Suzanne E. , Carvalho Diana , Viana-Pereira Marta , Tamber Narinder , Grigoriadis Anita E. , Ashworth Alan , Reis Rui M. , Ellison David W. , Al-Sarraj Safa , Hargrave Darren , Jones Chris
Published: June 2010

Purpose: As genome-scale technologies begin to unravel the complexity of the equivalent tumors in adults, we can attempt detailed characterization of high-grade gliomas in children, that have until recently been lacking. Toward this end, we sought to validate and extend investigations of the differences between pediatric and adult tumors.

Experimental Design: We carried out copy number profiling by array comparative genomic hybridization using a 32K bacterial artificial chromosome platform on 63 formalin-fixed paraffin-embedded cases of high-grade glioma arising in children and young people (<23 years).

Results: The genomic profiles of these tumors could be subclassified into four categories: those with stable genomes, which were associated with a better prognosis; those with aneuploid and those with highly rearranged genomes; and those with an amplifier genotype, which had a significantly worse clinical outcome. Independent of this was a clear segregation of cases with 1q gain (more common in children) from those with concurrent 7 gain/10q loss (a defining feature of adults). Detailed mapping of all the amplification and deletion events revealed numerous low-frequency amplifications, including IGF1R, PDGFRB, PIK3CA, CDK6, CCND1, and CCNE1, and novel homozygous deletions encompassing unknown genes, including those at 5q35, 10q25, and 22q13. Despite this, aberrations targeting the “core signaling pathways” in adult glioblastomas are significantly underrepresented in the pediatric setting.

Conclusions: These data highlight that although there are overlaps in the genomic events driving gliomagenesis of all ages, the pediatric disease harbors a distinct spectrum of copy number aberrations compared with adults. Clin Cancer Res; 16(13); 3368–77. ©2010 AACR.
Phage Display–Derived Peptides for Osteosarcoma Imaging
Authors: Sun Xilin , Niu Gang , Yan Yongjun , Yang Min , Chen Kai , Ma Ying , Chan Nicholas , Shen Baozhong , Chen Xiaoyuan
Published: June 2010

Purpose: Osteosarcoma represents the most common malignant primary bone tumor in childhood; however, the survival rate has remained unchanged for the past 20 years. To improve existing diagnosis and treatment methods and broaden the spectrum of imaging agents that can be used for early detection and assessment of tumor response to therapy, we performed a phage display–based screening for peptide sequences that bind specifically to osteosarcoma cells.

Experimental Design: From the Ph.D.-12 phage display peptide library composed of 2.7 × 109 different displayed peptides, one peptide was enriched after four rounds of in vitro selection in 143B osteosarcoma tumor cells with 293T human embryonic kidney cells as a control. Both the peptide and the phage clone displaying the peptide were conjugated with fluorescent dyes for in vitro cell and ex vivo tumor tissue stainings. The peptide was further labeled with 18F for positron emission tomography imaging studies. Cell uptake and efflux and ex vivo biodistribution were also done with 18F-labeled osteosarcoma specific peptide.

Results: ASGALSPSRLDT was the dominant sequence isolated from biopanning and named as OSP-1. OSP-1 shares a significant homology with heparinase II/III family protein, which binds and reacts with heparan sulfate proteoglycans. The fluorescence staining showed that FITC-OSP-1-phage or Cy5.5-OSP-1 had high binding with a panel of osteosarcoma cell lines, much less binding with UM-SCC1 human head and neck squamous cell carcinoma cells, and almost no binding with 293T cells, whereas the scrambled peptide OSP-S had virtually no binding to all the cell lines. 18F-OSP-1 had significantly higher accumulation in 143B tumor cells both in vitro and in vivo than 18F-OSP-S. 18F-OSP-1 also had higher uptake in 143B tumors than in UM-SCC-1 tumors.

Conclusions: Our data suggest that OSP-1 peptide is osteosarcoma specific, and the binding site of OSP-1 might be related to heparan sulfate proteoglycans. Appropriately labeled OSP-1 peptide has the potential to serve as a novel probe for osteosarcoma imaging. Clin Cancer Res; 16(16); 4268–77. ©2010 AACR.
MK-2206, an Allosteric Akt Inhibitor, Enhances Antitumor Efficacy by Standard Chemotherapeutic Agents or Molecular Targeted DrugsIn vitroandIn vivo
Authors: Hirai Hiroshi , Sootome Hiroshi , Nakatsuru Yoko , Miyama Katsuyoshi , Taguchi Shunsuke , Tsujioka Kyoko , Ueno Yoko , Hatch Harold , Majumder Pradip K. , Pan Bo-Sheng , Kotani Hidehito
Published: June 2010

The serine/threonine kinase Akt lies at a critical signaling node downstream of phosphatidylinositol-3-kinase and is important in promoting cell survival and inhibiting apoptosis. An Akt inhibitor may be particularly useful for cancers in which increased Akt signaling is associated with reduced sensitivity to cytotoxic agents or receptor tyrosine kinase inhibitors. We evaluated the effect of a novel allosteric Akt inhibitor, MK-2206, in combination with several anticancer agents. In vitro, MK-2206 synergistically inhibited cell proliferation of human cancer cell lines in combination with molecular targeted agents such as erlotinib (an epidermal growth factor receptor inhibitor) or lapatinib (a dual epidermal growth factor receptor/human epidermal growth factor receptor 2 inhibitor). Complementary inhibition of erlotinib-insensitive Akt phosphorylation by MK-2206 was one mechanism of synergism, and a synergistic effect was found even in erlotinib-insensitive cell lines. MK-2206 also showed synergistic responses in combination with cytotoxic agents such as topoisomerase inhibitors (doxorubicin, camptothecin), antimetabolites (gemcitabine, 5-fluorouracil), anti-microtubule agents (docetaxel), and DNA cross-linkers (carboplatin) in lung NCI-H460 or ovarian A2780 tumor cells. The synergy with docetaxel depended on the treatment sequence; a schedule of MK-2206 dosed before docetaxel was not effective. MK-2206 suppressed the Akt phosphorylation that is induced by carboplatin and gemcitabine. In vivo, MK-2206 in combination with these agents exerted significantly more potent tumor inhibitory activities than each agent in the monotherapy setting. These findings suggest that Akt inhibition may augment the efficacy of existing cancer therapeutics; thus, MK-2206 is a promising agent to treat cancer patients who receive these cytotoxic and/or molecular targeted agents. Mol Cancer Ther; 9(7); 1956–67. ©2010 AACR.
Mcl-1 Stability Determines Mitotic Cell Fate of Human Multiple Myeloma Tumor Cells Treated with the Kinesin Spindle Protein Inhibitor ARRY-520
Authors: Tunquist Brian J. , Woessner Richard D. , Walker Duncan H.
Published: June 2010

Kinesin spindle protein (KSP/Eg5) inhibitors are novel anticancer agents that have thus far shown only modest activity in the clinic. Understanding how to identify patients who may be most sensitive to treatment is clearly needed to improve the development of these molecules. We studied four multiple myeloma cell lines treated with the KSP inhibitor ARRY-520 to identify factors important for initiating apoptosis while cells are arrested in mitosis. The majority (three of four) of cell lines underwent mitotic arrest, with apoptosis occurring in mitosis within 24 to 30 hours. The remaining line (NCI H929) is temporally refractory to ARRY-520 treatment, undergoing mitotic slippage and subsequently peaking in apoptotic markers after 72 hours of treatment, while most cells are in interphase. Interestingly, loss of the antiapoptotic protein myeloid cell leukemia 1 (Mcl-1) coincided with mitotic cell death. Stabilization of Mcl-1 resulted in a delayed onset of apoptosis, whereas enforced downregulation of Mcl-1 increased cell death in response to KSP inhibition. Thus, variation in responses to KSP inhibition is governed by a balance between survival proteins and spindle checkpoint integrity. Cells relying on short-lived survival proteins during mitosis are more likely to undergo apoptosis in response to KSP inhibition. We propose that patients with hematologic malignancies, which rely on Mcl-1, would therefore be good candidates for treatment with KSP inhibitors. Mol Cancer Ther; 9(7); 2046–56. ©2010 AACR.
Sensitivity of Cancer Cells to Plk1 Inhibitor GSK461364A Is Associated with Loss of p53 Function and Chromosome Instability
Authors: Degenhardt Yan , Greshock Joel , Laquerre Sylvie , Gilmartin Aidan G. , Jing Junping , Richter Mark , Zhang Xiping , Bleam Maureen , Halsey Wendy , Hughes Ashley , Moy Christopher , Liu-Sullivan Nancy , Powers Scott , Bachman Kurtis , Jackson Jeffrey , Weber Barbara , Wooster Richard
Published: June 2010

Polo-like kinases are a family of serine threonine kinases that are critical regulators of cell cycle progression and DNA damage response. Predictive biomarkers for the Plk1-selective inhibitor GSK461364A were identified by comparing the genomics and genetics of a panel of human cancer cell lines with their response to a drug washout followed by an outgrowth assay. In this assay, cell lines that have lost p53 expression or carry mutations in the TP53 gene tended to be more sensitive to GSK461364A. These more sensitive cell lines also had increased levels of chromosome instability, a characteristic associated with loss of p53 function. Further mechanistic studies showed that p53 wild-type (WT) and not mutant cells can activate a postmitotic tetraploidy checkpoint and arrest at pseudo-G1 state after GSK461364A treatment. RNA silencing of WT p53 increased the antiproliferative activity of GSK461364A. Furthermore, silencing of p53 or p21/CDKN1A weakened the tetraploidy checkpoint in cells that survived mitotic arrest and mitotic slippage. As many cancer therapies tend to be more effective in p53 WT patients, the higher sensitivity of p53-deficient tumors toward GSK461364A could potentially offer an opportunity to treat tumors that are refractory to other chemotherapies as well as early line therapy for these genotypes. Mol Cancer Ther; 9(7); 2079–89. ©2010 AACR.
PS-341 and Histone Deacetylase Inhibitor Synergistically Induce Apoptosis in Head and Neck Squamous Cell Carcinoma Cells
Authors: Kim JinKoo , Guan Jean , Chang Insoon , Chen Xiaohong , Han Demin , Wang Cun-Yu
Published: June 2010

Proteasome inhibitor PS-341 (also known as bortezomib) and histone deacetylase (HDAC) inhibitors have emerged as novel therapeutic agents for a variety of malignancies. In this study, we examined whether PS-341 and the HDAC inhibitor trichostatin A (TSA) induced apoptosis in head and neck squamous cell carcinoma (HNSCC), a common and lethal malignancy. We found that, although TSA treatment alone did not induce apoptosis in HNSCC cells, it significantly enhanced PS-341–induced apoptosis in HNSCC cells in vitro. Consistently, TSA significantly improved PS-341–mediated inhibition of HNSCC tumor growth in nude mice. Mechanistically, we found that TSA increased PS-341–induced Noxa expression and caspase activation in HNSCC cells. The knockdown of Noxa significantly reduced apoptosis induced by cotreatment of PS-341 and TSA. Taken together, our results provide new insight into the mechanisms of synergistic antitumor activity of the PS-341 and HDAC inhibitor regimen, offering a new therapeutic strategy for HNSCC patients. Mol Cancer Ther; 9(7); 1977–84. ©2010 AACR.
The Dynamin Inhibitors MiTMAB and OcTMAB Induce Cytokinesis Failure and Inhibit Cell Proliferation in Human Cancer Cells
Authors: Joshi Sanket , Perera Swetha , Gilbert Jayne , Smith Charlotte M. , Mariana Anna , Gordon Christopher P. , Sakoff Jennette A. , McCluskey Adam , Robinson Phillip J. , Braithwaite Antony W. , Chircop Megan
Published: June 2010

The endocytic protein dynamin II (dynII) participates in cell cycle progression and has roles in centrosome cohesion and cytokinesis. We have described a series of small-molecule inhibitors of dynamin [myristyl trimethyl ammonium bromides (MiTMAB)] that competitively interfere with the ability of dynamin to bind phospholipids and prevent receptor-mediated endocytosis. We now report that dynII functions specifically during the abscission phase of cytokinesis and that MiTMABs exclusively block this step in the cell cycle. Cells treated with MiTMABs (MiTMAB and octadecyltrimethyl ammonium bromide) and dyn-depleted cells remain connected via an intracellular bridge for a prolonged period with an intact midbody ring before membrane regression and binucleate formation. MiTMABs are the first compounds reported to exclusively block cytokinesis without affecting progression through any other stage of the cell cycle. Thus, MiTMABs represent a new class of antimitotic compounds. We show that MiTMABs are potent inhibitors of cancer cell growth and have minimal effect on nontumorigenic fibroblast cells. Thus, MiTMABs have toxicity and antiproliferative properties that preferentially target cancer cells. This suggests that dynII may be a novel target for pharmacologic intervention for the treatment of cancer. Mol Cancer Ther; 9(7); 1995–2006. ©2010 AACR.
Tissue Inhibitor of Metalloproteinase-2 Regulates Matrix Metalloproteinase-2–Mediated Endothelial Barrier Dysfunction and Breast Cancer Cell Transmigration through Lung Microvascular Endothelial Cells
Authors: Shen Qiang , Lee Eugene S. , Pitts Robert L. , Wu Mack H. , Yuan Sarah Y.
Published: June 2010

Matrix metalloproteinases (MMP) have been implicated in multiple stages of cancer metastasis. Tissue inhibitor of metalloproteinase-2 (TIMP-2) plays an important role in regulating MMP-2 activity. By forming a ternary complex with pro-MMP-2 and its activator MMP-14 on the cell surface, TIMP-2 can either initiate or restrain the cleavage and subsequent activation of MMP-2. Our recent work has shown that breast cancer cell adhesion to vascular endothelial cells activates endothelial MMP-2, promoting tumor cell transendothelial migration (TEME). However, the mechanism of MMP-2 regulation during TEME remains unclear. In the current study, we present evidence that MMP-14 is expressed in both invasive breast cancer cells (MDA-MB-231 and MDA-MB-436) and lung microvascular endothelial cells (HBMVEC-L), whereas TIMP-2 is exclusively expressed and released from the cancer cells. The tumor cell–derived TIMP-2 was further identified as a major determinant of endothelial MMP-2 activity during tumor cell transmigration in the presence of MMP-14. This response was associated with endothelial barrier dysfunction because coculture of MDA-MB-231 or MDA-MB-436 with HBMVEC-L caused a significant decrease in transendothelial electrical resistance concomitantly with endothelial cell-cell junction disruption and tumor cell transmigration. Knockdown of TIMP-2 or inhibition of TIMP-2/MMP-14 attenuated MMP-2–dependent transendothelial electrical resistance response and TEME. These findings suggest a novel interactive role of breast cancer cells and vascular endothelial cells in regulating the TIMP-2/MMP-14/MMP-2 pathway during tumor metastasis. Mol Cancer Res; 8(7); 939–51. ©2010 AACR.
The Predominant WT1 Isoform (+KTS) Encodes a DNA-Binding Protein Targeting the Planar Cell Polarity Gene Scribble in Renal Podocytes
Authors: Wells Julie , Rivera Miguel N. , Kim Woo Jae , Starbuck Kristen , Haber Daniel A.
Published: June 2010

WT1 encodes a tumor suppressor first identified by its inactivation in Wilms' Tumor. Although one WT1 splicing variant encodes a well-characterized zinc finger transcription factor, little is known about the function of the most prevalent WT1 isoform, whose DNA binding domain is disrupted by a three–amino acid (KTS) insertion. Using cells that conditionally express WT1(+KTS), we undertook a genome-wide chromatin immunoprecipitation and cloning analysis to identify candidate WT1(+KTS)–regulated promoters. We identified the planar cell polarity gene Scribble (SCRB) as the first WT1(+KTS) target gene in podocytes of the kidney. WT1 and SCRB expression patterns overlap precisely in developing renal glomeruli of mice, and WT1(+KTS) binds to a 33-nucleotide region within the Scribble promoter in mouse and human cell lines and kidneys. Together, our results support a role for the predominant WT1(+KTS) isoform in transcriptional regulation and suggest a link between the WT1-dependent tumor suppressor pathway and a key component of the planar cell polarity pathway. Mol Cancer Res; 8(7); 975–85. ©2010 AACR.
Targeting Activating Transcription Factor 3 by Galectin-9 Induces Apoptosis and Overcomes Various Types of Treatment Resistance in Chronic Myelogenous Leukemia
Authors: Kuroda Junya , Yamamoto Mio , Nagoshi Hisao , Kobayashi Tsutomu , Sasaki Nana , Shimura Yuji , Horiike Shigeo , Kimura Shinya , Yamauchi Akira , Hirashima Mitsuomi , Taniwaki Masafumi
Published: June 2010

Tyrosine kinase inhibitors (TKI) against Bcr-Abl are the first-line therapeutics for chronic myelogenous leukemia (CML). However, the resistance to Bcr-Abl TKIs is induced in leukemic cells not only by loss of sensitivity to TKIs through Bcr-Abl–related molecular mechanisms but also by loss of addiction to Bcr-Abl TK activity by acquiring Bcr-Abl–unrelated additional oncogenic mutations. Therefore, the identification of an additional therapeutic target has been anticipated for achievement of a complete cure and to overcome resistance to treatment. We here showed that modified human Galectin-9 (hGal9), a lectin that show specific affinity for β-galactosides, inhibits the proliferation of five CML-derived cell lines by inducing apoptosis at their IC50s from 17.5 to 164.9 nmol/L. Our study revealed that activating transcription factor 3 (ATF3), a member of the ATF/cAMP-responsive element binding protein family transcription factors, is the critical mediator for cell killing by hGal9, and that Noxa is one of the downstream effector molecules of ATF3. Bim, on the other hand, the BH3-only protein essential for apoptosis by Bcr-Abl TKIs, was not associated with hGal9-induced cell death. ATF3-mediated cell death by hGal9 was not hampered by the absence of p53, the presence of mutant AblT315I, or by P-glycoprotein overexpression. In addition, hGal9 showed the additive growth-inhibitory effect with imatinib on CML cell lines. Collectively, hGal9 is a candidate agent that may overcome various kinds of resistance to treatment for CML and may suggest that ATF3 may be a new target molecule for the development of new treatment modalities that can overcome resistance to currently available chemotherapeutics. Mol Cancer Res; 8(7); 994–1001. ©2010 AACR.
Epidermal Growth Factor Receptor Expression and Gene Copy Number in the Risk of Oral Cancer
Authors: Taoudi Benchekroun Mohammed , Saintigny Pierre , Thomas Sufi M. , El-Naggar Adel K. , Papadimitrakopoulou Vassiliki , Ren Hening , Lang Wenhua , Fan You-Hong , Huang Jianhua , Feng Lei , Lee J. Jack , Kim Edward S. , Hong Waun Ki , Johnson Faye M. , Grandis Jennifer R. , Mao Li
Published: June 2010

Leukoplakia is the most common premalignant lesion of the oral cavity. Epidermal growth factor receptor (EGFR) abnormalities are associated with oral tumorigenesis and progression. We hypothesized that EGFR expression and gene copy number changes are predictors of the risk of an oral premalignant lesion (OPL) progressing to oral squamous cell carcinoma (OSCC). A formalin-fixed, paraffin-embedded OPL biopsy specimen was collected from each of 162 patients in a randomized controlled clinical trial. We assessed EGFR expression by immunohistochemistry with two methods: a semiquantitative analysis (145 evaluable specimens) and an automated quantitative analysis (127 evaluable specimens). EGFR gene copy number was assessed by fluorescence in situ hybridization (FISH) in a subset of 49 OPLs with high EGFR expression defined by the semiquantitative analysis. We analyzed EGFR abnormalities for associations with OSCC development. High EGFR expression occurred in 103 (71%) of the 145 OPLs and was associated with a nonsignificantly higher risk of OSCC (P = 0.10). Twenty (41%) of 49 OPLs assessed by FISH had an increased EGFR gene copy number (FISH-positive). Patients with FISH-positive lesions had a significantly higher incidence of OSCC than did patients with FISH-negative (a normal copy number) lesions (P = 0.0007). Of note, 10 of 11 OSCCs that developed at the site of the examined OPL were in the FISH-positive group, leaving only one FISH-negative OPL that did so (P < 0.0001). Our data indicate that an increased EGFR gene copy number is common in and associated with OSCC development in patients with OPLs expressing high EGFR, particularly OSCC developing at the site of a high-expression OPL; they also suggest that EGFR inhibitors may prevent oral cancer in patients with OPLs having an increased EGFR gene copy number. Cancer Prev Res; 3(7); 800–9. ©2010 AACR.
The Epidermal Growth Factor Receptor Axis: Support for a New Target for Oral Premalignancy
Authors: Rosin Miriam P. , Califano Joseph A.
Published: June 2010

This perspective on the report by Benchekroun et al. in this issue of the journal (beginning on page 800) examines new studies of factors in the epidermal growth factor receptor (EGFR) axis (including copy number alterations at the EGFR locus) that potentially predict the development of oral cancer; this work was conducted in a chemoprevention trial cohort of patients with oral premalignant lesions. The new data raise the possibility that a subset of oral premalignant lesions may benefit from specific therapeutic targeting of the EGFR axis. Cancer Prev Res; 3(7); 797–9. ©2010 AACR.
Nutritional Management of Phenylketonuria
Authors: MacLeod Erin L. , Ney Denise M.
Published: June 2010

Phenylketonuria (PKU) is caused by deficient activity of the enzyme phenylalanine hydroxylase, needed to convert the essential amino acid (AA) phenylalanine (phe) to tyrosine. In order to prevent neurological damage, lifelong adherence to a low-phe diet that is restricted in natural foods and requires ingestion of a phe-free AA formula to meet protein needs is required. The goal of nutritional management for those with PKU is to maintain plasma phe concentrations that support optimal growth, development, and mental functioning while providing a nutritionally complete diet. This paper reviews developing a lifelong dietary prescription for those with PKU, outcomes of nutritional management, compliance with the low-phe diet across the life cycle, and new options for nutritional management. An individualized dietary prescription is needed to meet nutrient requirements, and the adequacy of phe intake is monitored with assessment of blood phe levels. Elevated phe concentrations may occur due to illness, excessive or inadequate phe intake, or inadequate intake of AA formula. Although normal growth and development occurs with adherence to the low-phe diet, it is important to monitor vitamin, mineral and essential fatty acid status, especially in those who do not consume sufficient AA formula. Given the growing population of adults with PKU, further research is needed to understand the risks for developing osteoporosis and cardiovascular disease. There are promising new options to liberalize the diet and improve metabolic control such as tetrahydrobiopterin therapy or supplementation with large neutral AAs. Moreover, foods made with glycomacropeptide, an intact protein that contains minimal phe, improves the PKU diet by offering a palatable alternative to AA formula. In summary, continued efforts are needed to overcome the biggest challenge to living with PKU – lifelong adherence to the low-phe diet.
Novel Approaches to the Therapy of Phenylketonuria
Authors: Eavri Ronen , Lorberboum-Galski Haya
Published: June 2010

Since its discovery by Følling in 1934, phenylketonuria (PKU) has been the subject of numerous research studies spanning many disciplines including human genetics, biochemistry, development, neurobiology and others. During the last 75 years, different mutations in the genes responsible for the disease have been mapped, the biochemical basis has been elucidated and the flawed mechanisms leading to the clinical outcome have been revealed. Moreover, the newborn screening programs based on the Guthrie test and the subsequent biochemical analysis in newborn children, in addition to the low-protein diet, have all made a tremendous impact on the way inherited inborn errors of metabolism have been looked upon in these modern times. In fact, this simple yet most effective treatment for PKU – the low-protein diet – is considered a breakthrough in treatment of the disease enabling the retention of low levels of phenylalanine in the blood, thus preventing the high and persistent phenylalanine levels from damaging normal brain development. However, despite the simplicity and high effectiveness of the low-protein diet treatment, the incompliance of some PKU patients and the consequences that are associated with it have led scientists to constantly seek new and alternative methods for treatment. In this review, we discuss major advances in PKU therapy, including suggested new cures. We remain optimistic that one or more of the potential cures reviewed here will evolve into future medications for PKU patients.