bluuebunny/crossref_metadata_2025 huggingface dataset:
Evolution and morphology of saucer-shaped sills in analogue experiments
Authors: Bunger Andrew P. , Jeffrey Robert G. , Detournay Emmanuel
Published: July 2008

The growth of shallow sills is studied in analogue experiments performed in polymethyl methacrylate (PMMA) and glass. The experimental fractures curve towards the surface to become saucer-shaped, which is consistent with many field observations of dolerite sills. The curvature of the saucer is shown to decrease as the
in situ
stress acting parallel to the surface increases relative to an estimate of the strength of the fracture-induced stress field. The initially circular fractures also elongate in plan view to become egg-shaped, a tendency that decreases with increasing importance of viscous dissipation in the growth process. Sill emplacement is further examined mathematically by considering a shallow, circular, fluid-driven fracture propagating in a homogeneous brittle elastic material. The fractures are shown to undergo three transitions related to the mechanics of sill growth. Each transition is associated with a characteristic time that is derived from analysis of the governing equations using scaling methods. These characteristic times provide an estimate of how long viscous flow is the dominant energy dissipation mechanism, how long significant lag between the fluid and fracture fronts is expected to persist, and how long the sill will take to attain an extent that is of the same order as its depth.
Charm Meson Decays
Authors: Artuso Marina , Meadows Brian , Petrov Alexey A.
Published: July 2008

We review some recent developments in charm meson physics. In particular, we discuss the theoretical predictions and experimental measurements of charmed meson decays to leptonic, semileptonic, and hadronic final states and the implications of such measurements to searches for new physics. We discuss [Formula: see text] mixing and CP violation in charm, as well as future experimental prospects and theoretical challenges in this area.
Therapeutic targeting of human hepatocyte growth factor with a single neutralizing monoclonal antibody reduces lung tumorigenesis
Authors: Stabile Laura P. , Rothstein Mary E. , Keohavong Phouthone , Jin Jide , Yin Jinling , Land Stephanie R. , Dacic Sanja , Luong The Minh , Kim K. Jin , Dulak Austin M. , Siegfried Jill M.
Published: July 2008

The hepatocyte growth factor (HGF)/c-Met signaling pathway is involved in lung tumor growth and progression, and agents that target this pathway have clinical potential for lung cancer treatment. L2G7, a single potent anti-human HGF neutralizing monoclonal antibody, showed profound inhibition of human HGF-induced phosphorylated mitogen-activated protein kinase induction, wound healing, and invasion in lung tumor cells in vitro. Transgenic mice that overexpress human HGF in the airways were used to study the therapeutic efficacy of L2G7 for lung cancer prevention. Mice were treated with the tobacco carcinogen, nitrosamine 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone, over 4 weeks. Beginning at week 3, i.p. treatment with 100 μg L2G7 or isotype-matched antibody control, 5G8, was initiated and continued through week 15. The mean number of tumors per mouse in the L2G7-treated group was significantly lower than in the control group (1.58 versus 3.19; P = 0.0005). Proliferative index was decreased by 48% (P = 0.013) in tumors from L2G7-treated mice versus 5G8-treated mice, whereas extent of apoptosis was increased in these same tumors by 5-fold (P = 0.0013). Phosphorylated mitogen-activated protein kinase expression was also significantly decreased by 84% in tumors from L2G7-treated mice versus 5G8-treated mice (P = 0.0003). Tumors that arose in HGF transgenic animals despite L2G7 treatment were more likely to contain mutant K-ras, suggesting that targeting the HGF/c-Met pathway may not be as effective if downstream signaling is activated by a K-ras mutation. These preclinical results show that blocking the HGF/c-Met interaction with a single monoclonal antibody delivered systemically can have profound inhibitory effects on development of lung tumors. [Mol Cancer Ther 2008;7(7):1913–22]
Single-chain antibody/activated BID chimeric protein effectively suppresses HER2-positive tumor growth
Authors: Qiu Xiu-Chun , Xu Yan-Ming , Wang Fang , Fan Qing-Yu , Wang Li-Feng , Ma Bao-An , Jia Lin-Tao , Zhao Jing , Meng Yan-Ling , Yao Li-Bo , Chen Si-Yi , Yang An-Gang
Published: July 2008

BH3-interacting domain death agonist (BID) is a crucial element in death signaling pathways and is recognized as an intracellular link connecting the intrinsic mitochondrial apoptotic and extrinsic death receptor–mediated apoptotic pathways. Herein, we describe experiments conducted with a fusion protein, which was generated by fusing a human epidermal growth factor receptor-2 (HER2)–specific single-chain antibody with domain II of Pseudomonas exotoxin A and the truncated active BID (tBID). These experiments extend our previous work on several other immuno-proapoptotic proteins. Specifically, by excluding cells with undetectable HER2, we showed that the secreted immuno-tBID molecule selectively recognized and killed HER2-overexpressing tumor cells in vitro by attacking their mitochondria and inducing their apoptotic death. This apoptosis could only be inhibited partially by caspase pan-inhibitor zVAD and mitochondrial protector TAT-BH4. Subsequently, we transferred the immuno-tbid gene into BALB/c athymic mice bearing HER2-positive tumors together with other immuno-proapoptotic proteins using i.m. injections of liposome-encapsulated vectors. The expression of the immuno-tbid gene suppressed tumor growth and prolonged animal survival significantly. We also shortened the translocation domain of Pseudomonas exotoxin A II to only 10–amino acid sequence, which were crucial for furin cleavage. The new recombinant molecule retained the translocation efficiency and the ability of specific killing HER2-positive tumor cells. Our data showed that, compared with the toxins employed before, the chimeric immuno-tBID molecule can not only specifically recognize HER2-positive tumor cells but also certainly induce apoptosis even in the presence of zVAD and TAT-BH4, thereby suggesting an alternative approach to treating HER2/neu-positive tumors. [Mol Cancer Ther 2008;7(7):1890–9]
Cyclooxygenase inhibitors block uterine tumorigenesis in HMGA1a transgenic mice and human xenografts
Authors: Di Cello Francescopaolo , Hillion Joelle , Kowalski Jeanne , Ronnett Brigitte M. , Aderinto Abimbola , Huso David L. , Resar Linda M.S.
Published: July 2008

Uterine cancer is a common cause for cancer death in women and there is no effective therapy for metastatic disease. Thus, research is urgently needed to identify new therapeutic agents. We showed previously that all female HMGA1a transgenic mice develop malignant uterine tumors, indicating that HMGA1a causes uterine cancer in vivo. We also demonstrated that HMGA1a up-regulates cyclooxygenase-2 (COX-2) during tumorigenesis in this model. Similarly, we found that HMGA1a and COX-2 are overexpressed in human leiomyosarcomas, a highly malignant uterine cancer. Although epidemiologic studies indicate that individuals who take COX inhibitors have a lower incidence of some tumors, these inhibitors have not been evaluated in uterine cancer. Here, we show that HMGA1a mice on sulindac (a COX-1/COX-2 inhibitor) have significantly smaller uterine tumors than controls. To determine if COX inhibitors are active in human uterine cancers that overexpress HMGA1a, we treated cultured cells with sulindac sulfide or celecoxib (a specific COX-2 inhibitor). Both drugs block anchorage-independent growth in high-grade human uterine cancer cells that overexpress HMGA1a (MES-SA cells). In contrast, neither inhibitor blocked transformation in cells that do not overexpress HMGA1a. Moreover, xenograft tumors from MES-SA cells were significantly inhibited in mice on sulindac. More strikingly, no tumors formed in mice on celecoxib. These preclinical studies suggest that COX inhibitors could play a role in preventing tumor onset or progression in uterine cancers with dysregulation of the HMGA1a-COX-2 pathway. Importantly, these drugs have lower toxicity than chemotherapeutic agents used to treat advanced-stage uterine cancers. [Mol Cancer Ther 2008;7(7):2090–5]
5,5′-Dibromo-bis(3′-indolyl)methane induces Krüppel-like factor 4 and p21 in colon cancer cells
Authors: Cho Sung Dae , Chintharlapalli Sudhakar , Abdelrahim Maen , Papineni Sabitha , Liu Shengxi , Guo Jingjing , Lei Ping , Abudayyeh Ala , Safe Stephen
Published: July 2008

Bis(3′-indolyl)methane (DIM) is a metabolite of the phytochemical indole-3-carbinol, and both compounds exhibit a broad spectrum of anticancer activities. We have developed a series of synthetic symmetrical ring-substituted DIM analogues, including 5,5′-dibromoDIM, which are more potent than DIM as inhibitors of cancer cell and tumor growth. In colon cancer cells, 5,5′-dibromoDIM decreased cell proliferation and inhibited G0-G1- to S-phase progression, and this was accompanied by induction of the cyclin-dependent kinase inhibitor p21 in HT-29 and RKO colon cancer cells. Mechanistic studies showed that induction of p21 in both RKO (p53 wild-type) and HT-29 (p53 mutant) cells by 5,5′-dibromoDIM was Krüppel-like factor 4 (KLF4) dependent, and induction of p53 in RKO cells was also KLF4 dependent. Analysis of the p21 promoter in p53-dependent RKO cells showed that 5,5′-dibromoDIM activated p21 gene expression through the proximal GC-rich sites 1 and 2, and chromatin immunoprecipitation assays showed that KLF4 and p53 bound to this region of the promoter, whereas in HT-29 cells unidentified upstream cis-elements were required for induction of p21. 5,5′-DibromoDIM (30 mg/kg/d) also inhibited tumor growth and induced p21 in athymic nude mice bearing RKO cells as xenografts, showing that ring-substituted DIM such as 5,5′-dibromoDIM represent a novel class of mechanism-based drugs for clinical treatment of colon cancer. [Mol Cancer Ther 2008;7(7):2109–20]
Apigenin inhibits antiestrogen-resistant breast cancer cell growth through estrogen receptor-α-dependent and estrogen receptor-α-independent mechanisms
Authors: Long Xinghua , Fan Meiyun , Bigsby Robert M. , Nephew Kenneth P.
Published: July 2008

Breast cancer resistance to the antiestrogens tamoxifen (OHT) and fulvestrant is accompanied by alterations in both estrogen-dependent and estrogen-independent signaling pathways. Consequently, effective inhibition of both pathways may be necessary to block proliferation of antiestrogen-resistant breast cancer cells. In this study, we examined the effects of apigenin, a dietary plant flavonoid with potential anticancer properties, on estrogen-responsive, antiestrogen-sensitive MCF7 breast cancer cells and two MCF7 sublines with acquired resistance to either OHT or fulvestrant. We found that apigenin can function as both an estrogen and an antiestrogen in a dose-dependent manner. At low concentrations (1 μmol/L), apigenin stimulated MCF7 cell growth but had no effect on the antiestrogen-resistant MCF7 sublines. In contrast, at high concentrations (>10 μmol/L), the drug inhibited growth of MCF7 cells and the antiestrogen-resistant sublines, and the combination of apigenin with either OHT or fulvestrant showed synergistic, growth-inhibitory effects on both antiestrogen-sensitive and antiestrogen-resistant breast cancer cells. To further elucidate the molecular mechanism of apigenin as either an estrogen or an antiestrogen, effects of the drug on estrogen receptor-α (ERα); transactivation activity, mobility, stability, and ERα-coactivator interactions were investigated. Low-dose apigenin enhanced receptor transcriptional activity by promoting interaction between ERα and its coactivator amplified in breast cancer-1. However, higher doses (>10 μmol/L) of apigenin inhibited ERα mobility (as determined by fluorescence recovery after photobleaching assays), down-regulated ERα and amplified in breast cancer-1 expression levels, and inhibited multiple protein kinases, including p38, protein kinase A, mitogen-activated protein kinase, and AKT. Collectively, these results show that apigenin can function as both an antiestrogen and a protein kinase inhibitor with activity against breast cancer cells with acquired resistance to OHT or fulvestrant. We conclude that apigenin, through its ability to target both ERα-dependent and ERα-independent pathways, holds promise as a new therapeutic agent against antiestrogen-resistant breast cancer. [Mol Cancer Ther 2008;7(7):2096–108]
Array-based analysis of the effects of trichostatin A and CG-1521 on cell cycle and cell death in LNCaP prostate cancer cells
Authors: Roy Somdutta , Jeffrey Randy , Tenniswood Martin
Published: July 2008

Previous studies comparing the effects of two histone deacetylase (HDAC) inhibitors, trichostatin A (TSA) and CG-1521, have shown that these compounds selectively inhibit HDAC and induce differentially acetylated p53 isoforms and assembly of mutually exclusive transcriptional complexes on the p21 promoter. To determine whether the differential transcriptional regulation seen in p21 gene is unique or whether it is representative of the genome-wide effects of these two HDAC inhibitors, we have used microarray and Ingenuity pathway analysis to compare the effects of TSA and CG-1521 on gene expression on LNCaP cells. Gene array analysis confirmed by quantitative real-time PCR shows that CG-1521 modulates the expression of a highly circumscribed group of genes involved in cell cycle progression and cell death. In contrast, TSA appears to induce widespread transrepression of many genes and does not modulate the expression of the same cohort as CG-1521. These data show that the selective effects of CG-1521 and TSA on the assembly of transcription complexes are not unique to the p21 gene and suggest that selective inhibition of HDAC can lead to significant changes in gene expression through the acetylation of transcription factors including but not limited to p53. [Mol Cancer Ther 2008;7(7):1931–9]
Proteomic characterization of cytoskeletal and mitochondrial class III β-tubulin
Authors: Cicchillitti Lucia , Penci Roberta , Di Michele Michela , Filippetti Flavia , Rotilio Domenico , Donati Maria Benedetta , Scambia Giovanni , Ferlini Cristiano
Published: July 2008

Class III β-tubulin (TUBB3) has been discovered as a marker of drug resistance in human cancer. To get insights into the mechanisms by which this protein is involved in drug resistance, we analyzed TUBB3 in a panel of drug-sensitive and drug-resistant cell lines. We identified two main different isoforms of TUBB3 having a specific electrophoretic profile. We showed that the apparently higher molecular weight isoform is glycosylated and phosphorylated and it is localized in the cytoskeleton. The apparently lower molecular weight isoform is instead found exclusively in mitochondria. We observed that levels of phosphorylation and glycosylation of TUBB3 are associated with the resistant phenotype and compartmentalization into cytoskeleton. By two-dimensional nonreduced/reduced SDS-PAGE analysis, we also found that TUBB3 protein in vivo forms protein complexes through intermolecular disulfide bridges. Through TUBB3 immunoprecipitation, we isolated protein species able to interact with TUBB3. Following trypsin digestion, these proteins were characterized by mass spectrometry analysis. Functional analysis revealed that these proteins are involved in adaptation to oxidative stress and glucose deprivation, thereby suggesting that TUBB3 is a survival factor able to directly contribute to drug resistance. Moreover, glycosylation of TUBB3 could represent an attractive pathway whose inhibition could hamper cytoskeletal compartmentalization and TUBB3 function. [Mol Cancer Ther 2008;7(7):2070–9]
Ritonavir induces endoplasmic reticulum stress and sensitizes sarcoma cells toward bortezomib-induced apoptosis
Authors: Kraus Marianne , Malenke Elke , Gogel Jeannette , Müller Holger , Rückrich Thomas , Overkleeft Herman , Ovaa Huib , Koscielniak Ewa , Hartmann Jörg Thomas , Driessen Christoph
Published: July 2008

The biosynthesis of immunoglobulin leads to constitutive endoplasmic reticulum (ER) stress in myeloma cells, which activates the unfolded protein response (UPR). The UPR promotes protein folding by chaperones and increases proteasomal degradation of misfolded protein. Excessive ER stress induces apoptosis and represents a molecular basis for the bortezomib sensitivity of myeloma. Most solid malignancies such as sarcoma, by contrast, are poorly bortezomib sensitive and display low levels of ER stress. We hypothesized that pharmacologic induction of ER stress might sensitize malignancies to bortezomib treatment. We show that the HIV protease inhibitor ritonavir induces ER stress in bortezomib-resistant sarcoma cells. Ritonavir triggered the UPR, decreased the degradation of newly synthesized protein, but did not directly inhibit proteasomal active sites in the therapeutic dose range in contrast to bortezomib. Whereas neither bortezomib nor ritonavir monotherapy translated into significant apoptosis at therapeutic drug levels, the combination strongly increased the level of ER stress and activated PERK, IRE1, and ATF6, synergistically induced CHOP, JNK, caspase-4, and caspase-9, and resulted in >90% apoptosis. In summary, ritonavir increases the level of ER stress induced by bortezomib, which sensitizes bortezomib-resistant cells to bortezomib-induced apoptosis. Ritonavir may therefore be tested clinically to improve the sensitivity of solid malignancies toward bortezomib treatment. [Mol Cancer Ther 2008;7(7):1940–8]
The natural product honokiol preferentially inhibits cellular FLICE-inhibitory protein and augments death receptor–induced apoptosis
Authors: Raja Shruti M. , Chen Shuzhen , Yue Ping , Acker Timothy M. , Lefkove Benjamin , Arbiser Jack L. , Khuri Fadlo R. , Sun Shi-Yong
Published: July 2008

Targeting death receptor–mediated apoptosis has emerged as an effective strategy for cancer therapy. However, certain types of cancer cells are intrinsically resistant to death receptor–mediated apoptosis. In an effort to identify agents that can sensitize cancer cells to death receptor–induced apoptosis, we have identified honokiol, a natural product with anticancer activity, as shown in various preclinical studies, as an effective sensitizer of death receptor–mediated apoptosis. Honokiol alone moderately inhibited the growth of human lung cancer cells; however, when combined with tumor necrosis factor–related apoptosis-inducing ligand (TRAIL), greater effects on decreasing cell survival and inducing apoptosis than TRAIL alone were observed, indicating that honokiol cooperates with TRAIL to enhance apoptosis. This was also true to Fas-induced apoptosis when combined with Fas ligand or an agonistic anti-Fas antibody. Among several apoptosis-associated proteins tested, cellular FLICE-inhibitory protein (c-FLIP) was the only one that was rapidly down-regulated by honokiol in all of the tested cell lines. The down-regulation of c-FLIP by honokiol could be prevented by the proteasome inhibitor MG132. Moreover, honokiol increased c-FLIP ubiquitination. These results indicate that honokiol down-regulates c-FLIP by facilitating its degradation through a ubiquitin/proteasome-mediated mechanism. Enforced expression of ectopic c-FLIP abolished the ability of honokiol to enhance TRAIL-induced apoptosis. Several honokiol derivatives, which exhibited more potent effects on down-regulation of c-FLIP than honokiol, showed better efficacy than honokiol in inhibiting the growth and enhancing TRAIL-induced apoptosis as well. Collectively, we conclude that c-FLIP down-regulation is a key event for honokiol to modulate the death receptor–induced apoptosis. [Mol Cancer Ther 2008;7(7):2212–23]
Prostate-specific membrane antigen associates with anaphase-promoting complex and induces chromosomal instability
Authors: Rajasekaran Sigrid A. , Christiansen Jason J. , Schmid Ingrid , Oshima Eri , Sakamoto Kathleen , Weinstein Jasminder , Rao Nagesh P. , Rajasekaran Ayyappan K.
Published: July 2008

Prostate-specific membrane antigen (PSMA) is a transmembrane protein highly expressed in advanced and metastatic prostate cancers. The pathologic consequence of elevated PSMA expression in not known. Here, we report that PSMA is localized to a membrane compartment in the vicinity of mitotic spindle poles and associates with the anaphase-promoting complex (APC). PSMA-expressing cells prematurely degrade cyclin B and exit mitosis due to increased APC activity and incomplete inactivation of APC by the spindle assembly checkpoint. Further, expression of PSMA in a karyotypically stable cell line induces aneuploidy. Thus, these findings provide the first evidence that PSMA has a causal role in the induction of aneuploidy and might play an etiologic role in the progression of prostate cancer. [Mol Cancer Ther 2008;7(7):2142–51]
Nordihydroguaiaretic acid, a cytotoxic insulin-like growth factor-I receptor/HER2 inhibitor in trastuzumab-resistant breast cancer
Authors: Rowe Danica L. , Ozbay Tuba , Bender Laura M. , Nahta Rita
Published: July 2008

The majority of patients with HER2-overexpressing metastatic breast cancer who initially respond to the HER2-targeted antibody trastuzumab show disease progression within 1 year. The identification of novel agents that effectively inhibit survival of cancer cells that have progressed on trastuzumab is critical for improving outcome for this patient population. In the current study, we show that the phenolic compound nordihydroguaiaretic acid (NDGA) promoted cell death of trastuzumab-naive and trastuzumab-refractory HER2-overexpressing breast cancer cells. NDGA induced DNA fragmentation, cleavage of poly(ADP-ribose) polymerase and caspase-3, and inhibition of colony formation. In addition, NDGA inhibited insulin-like growth factor-I and HER2 signaling in trastuzumab-refractory cells, with reduced downstream phosphatidylinositol-3 kinase/Akt signaling. Importantly, combination treatment with NDGA and trastuzumab suppressed proliferation and survival of trastuzumab-refractory cells to a greater degree than either agent alone, suggesting that NDGA increases the sensitivity of refractory cells to trastuzumab. Derivatives of NDGA are currently in clinical trial for other solid tumors. Our data strongly support further study of NDGA as a potential therapeutic against breast cancers that have progressed on trastuzumab. [Mol Cancer Ther 2008;7(7):1900–8]
Involvement of microRNA-451 in resistance of the MCF-7 breast cancer cells to chemotherapeutic drug doxorubicin
Authors: Kovalchuk Olga , Filkowski Jody , Meservy James , Ilnytskyy Yaroslav , Tryndyak Volodymyr P. , Chekhun Vasyl' F. , Pogribny Igor P.
Published: July 2008

Many chemotherapy regiments are successfully used to treat breast cancer; however, often breast cancer cells develop drug resistance that usually leads to a relapse and worsening of prognosis. We have shown recently that epigenetic changes such as DNA methylation and histone modifications play an important role in breast cancer cell resistance to chemotherapeutic agents. Another mechanism of gene expression control is mediated via the function of small regulatory RNA, particularly microRNA (miRNA); its role in cancer cell drug resistance still remains unexplored. In the present study, we investigated the role of miRNA in the resistance of human MCF-7 breast adenocarcinoma cells to doxorubicin (DOX). Here, we for the first time show that DOX-resistant MCF-7 cells (MCF-7/DOX) exhibit a considerable dysregulation of the miRNAome profile and altered expression of miRNA processing enzymes Dicer and Argonaute 2. The mechanistic link of miRNAome deregulation and the multidrug-resistant phenotype of MCF-7/DOX cells was evidenced by a remarkable correlation between specific miRNA expression and corresponding changes in protein levels of their targets, specifically those ones that have a documented role in cancer drug resistance. Furthermore, we show that microRNA-451 regulates the expression of multidrug resistance 1 gene. More importantly, transfection of the MCF-7/DOX-resistant cells with microRNA-451 resulted in the increased sensitivity of cells to DOX, indicating that correction of altered expression of miRNA may have significant implications for therapeutic strategies aiming to overcome cancer cell resistance. [Mol Cancer Ther 2008;7(7):2152–9]
Thymoquinone inhibits tumor angiogenesis and tumor growth through suppressing AKT and extracellular signal-regulated kinase signaling pathways
Authors: Yi Tingfang , Cho Sung-Gook , Yi Zhengfang , Pang Xiufeng , Rodriguez Melissa , Wang Ying , Sethi Gautam , Aggarwal Bharat B. , Liu Mingyao
Published: July 2008

Thymoquinone, a component derived from the medial plant Nigella sativa, has been used for medical purposes for more than 2,000 years. Recent studies reported that thymoquinone exhibited inhibitory effects on cell proliferation of many cancer cell lines and hormone-refractory prostate cancer by suppressing androgen receptor and E2F-1. Whether thymoquinone inhibits tumor angiogenesis, the critical step of tumor growth and metastasis, is still unknown. In this study, we found that thymoquinone effectively inhibited human umbilical vein endothelial cell migration, invasion, and tube formation. Thymoquinone inhibited cell proliferation and suppressed the activation of AKT and extracellular signal-regulated kinase. Thymoquinone blocked angiogenesis in vitro and in vivo, prevented tumor angiogenesis in a xenograft human prostate cancer (PC3) model in mouse, and inhibited human prostate tumor growth at low dosage with almost no chemotoxic side effects. Furthermore, we observed that endothelial cells were more sensitive to thymoquinone-induced cell apoptosis, cell proliferation, and migration inhibition compared with PC3 cancer cells. Thymoquinone inhibited vascular endothelial growth factor–induced extracellular signal-regulated kinase activation but showed no inhibitory effects on vascular endothelial growth factor receptor 2 activation. Overall, our results indicate that thymoquinone inhibits tumor angiogenesis and tumor growth and could be used as a potential drug candidate for cancer therapy. [Mol Cancer Ther 2008;7(7):1789–96]
Antiangiogenic vinflunine affects EB1 localization and microtubule targeting to adhesion sites
Authors: Honoré Stéphane , Pagano Alessandra , Gauthier Géraldine , Bourgarel-Rey Véronique , Verdier-Pinard Pascal , Civiletti Karine , Kruczynski Anna , Braguer Diane
Published: July 2008

The motile behavior of endothelial cells is a crucial event for neoangiogenesis. We previously showed that noncytotoxic concentrations of vinflunine inhibit capillary-like tube formation on Matrigel and endothelial cell migration with a concomitant increase in interphase microtubule dynamic instability. In this article, we further investigated the effects of vinflunine on migration and cytoskeleton interaction dynamics in HMEC-1 endothelial cells. We confirmed that vinflunine, at low and noncytotoxic concentrations (0.01–1 nmol/L), inhibited endothelial cell random motility by 54%. This effect was associated with a decrease in the percentage of stable microtubules and in the mean duration of pauses for dynamic ones. Moreover, we found that vinflunine altered adhesion site targeting by microtubules and suppressed the microtubule (+) end pause that occurs at adhesion sites during cell migration (from 151 ± 20 seconds in control cells to 38 ± 7 seconds in vinflunine-treated cells, P < 0.001). This effect was associated with the inhibition of adhesion site dynamics and the formation of long-lived stress fibers. Importantly, we found that vinflunine altered EB1 localization at microtubule (+) ends. These results highlight a new mechanism of action of vinflunine, which act by disrupting the mutual control between microtubule and adhesion site dynamics and strengthen the role of +TIPs proteins such as EB1 as key regulators of endothelial cell motility. [Mol Cancer Ther 2008;7(7):2080–9]
Hypoxia-induced resistance to anticancer drugs is associated with decreased senescence and requires hypoxia-inducible factor-1 activity
Authors: Sullivan Richard , Paré Geneviève C. , Frederiksen Lisa J. , Semenza Gregg L. , Graham Charles H.
Published: July 2008

Hypoxia in solid tumors is associated with the development of chemoresistance. Although many studies have focused on the effect of hypoxia on drug-induced apoptosis, the effect of nonapoptotic pathways on hypoxia-induced drug resistance has not been previously investigated. Here, we determined the effects of hypoxia on multiple forms of drug-induced death in human MDA-MB-231 breast carcinoma cells. Clonogenic assays showed that preexposure to hypoxia leads to resistance to various classes of chemotherapeutic agents, including anthracyclines (daunorubicin and doxorubicin), epipodophyllotoxins (etoposide), and anthracenediones (mitoxantrone). Results revealed a high degree of heterogeneity in nuclear and cytoplasmic alterations in response to acute drug exposure; however, the majority of exposed cells displayed morphologic and biochemical changes consistent with drug-induced senescence. Hypoxia decreased only the proportion of cells in the senescent population, whereas the small proportion of cells exhibiting features of apoptosis or mitotic catastrophe were unaffected. Similar results were obtained with human HCT116 colon carcinoma cells, indicating that the protective effect of hypoxia on drug-induced senescence is not unique to MDA-MB-231 cells. Treatment of MDA-MB-231 cells with small interfering RNA targeting the α-subunit of hypoxia-inducible factor-1 (HIF-1), a key regulator of cellular adaptations to hypoxia, prevented hypoxia-induced resistance. HIF-1α small interfering RNA also selectively abolished the hypoxia-induced changes in the senescent population, indicating that the increased survival was due to protection against drug-induced senescence. These results support a requirement for HIF-1 in the adaptations leading to drug resistance and reveal that decreased drug-induced senescence is also an important contributor to the development of hypoxia-induced resistance. [Mol Cancer Ther 2008;7(7):1961–73]
Preclinical profile of antitumor activity of a novel hydrophilic camptothecin, ST1968
Authors: Pisano Claudio , De Cesare Michelandrea , Beretta Giovanni Luca , Zuco Valentina , Pratesi Graziella , Penco Sergio , Vesci Loredana , Foderà Rosanna , Ferrara Fabiana Fosca , Guglielmi Mario Berardino , Carminati Paolo , Dallavalle Sabrina , Morini Gabriella , Merlini Lucio , Orlandi Augusto , Zunino Franco
Published: July 2008

ST1968 is a novel hydrophilic camptothecin (CPT) derivative of the 7-oxyiminomethyl series. Because ST1968 retained ability to form remarkably stable cleavable complexes, this study was done to investigate its preclinical profile of antitumor activity in a large panel of human tumor models, including irinotecan-resistant tumors. Although less potent than SN38 in vitro, i.v. administered ST1968 caused a marked tumor inhibition, superior to that of irinotecan, in most tested models. ST1968 exhibited an impressive activity against several tumors including models of ovarian and colon carcinoma in which a high rate of cures was observed. In the most responsive tumors, complete and persistent tumor regressions were achieved even with low suboptimal doses. Even tumors derived from intrinsically resistant cells exhibited a significant responsiveness. Histologic analysis of treated tumors supports a contribution of both proapoptotic and antiangiogenic effects to ST1968 antitumor efficacy. A study done in yeast cells transformed with CPT-resistant mutant forms of topoisomerase I documented that, in contrast to other tested CPT, ST1968 was active against yeasts expressing the mutant K720E enzyme. Based on its outstanding efficacy superior to that of irinotecan and of its good therapeutic index, ST1968 has been selected for clinical development. [Mol Cancer Ther 2008;7(7):2051–9]
Synergistic tumoricidal effect of combined hMUC1 vaccination and hNIS radioiodine gene therapy
Authors: Jeon Yong Hyun , Choi Yun , Yoon Sun Och , Kim Chul Woo , Chung June-Key
Published: July 2008

We examined the merits of combinatorial hMUC1 vaccination and hNIS radioiodine gene therapy and evaluated its tumoricidal effects in an animal tumor model. CMNF (CT26 expressing hMUC1, hNIS, and firefly luciferase) cells were transplanted into 28 mice, and 4 and 11 days after tumor challenge, tumor-bearing mice were immunized i.m. with pcDNA3.1 or pcDNA-hMUC1 vaccine and subsequently administered PBS or 131I i.p. [four groups (7 mice per group): pcDNA3.1 + PBS, phMUC1 + PBS, pcDNA3.1 + 131I, and phMUC1 + 131I groups]. Thirty-two days after tumor challenge, we rechallenged mice in the pcDNA3.1 + 131I and phMUC1 + 131I groups with CMNF cells. Tumor progression and tumor-free mice (%) were monitored by bioluminescence. We investigated hMUC1-associated immune response generated by combination therapy. Marked tumor growth inhibition was observed in the phMUC1 + 131I group by bioluminescence at 32 days after tumor challenge. Mice in phMUC1 + 131I group showed complete hMUC1-expressing tumor suppression after tumor rechallenge, whereas mice in the pcDNA3.1 + 131I group did not. The tumor-free mice (%) were much higher in the phMUC1 + 131I group than in the other three groups. Levels of hMUC1-associated CD8+IFN-γ+ T cells were higher in the phMUC1 + 131I group than in the other three groups. hMUC1-loaded CD11+ cells in the phMUC1 + 131I group were found to be most effective at generating hMUC1-associated CD8+IFN-γ+ T cells. The activities of hMUC1-associated cytotoxic T cells in the phMUC1 + 131I group were higher than in the other three groups. Our data suggest that phMUC1 + 131I combination therapy synergistically generates marked tumoricidal effects against established hMUC1-expressing cancers. [Mol Cancer Ther 2008;7(7):2252–60]
Arsenic trioxide enhances the therapeutic efficacy of radiation treatment of oral squamous carcinoma while protecting bone
Authors: Kumar Pawan , Gao Qinghong , Ning Yu , Wang Zhuo , Krebsbach Paul H. , Polverini Peter J.
Published: July 2008

Therapeutic radiation is commonly used in the treatment of squamous cell carcinoma of the oral cavity and pharynx. Despite the proven efficacy of this form of anticancer therapy, high-dose radiation treatment is invariably associated with numerous unwanted side effects. This is particularly true for bone, in which radiation treatment often leads to osteoradionecrosis. The aim of this study was to investigate if treatment with arsenic trioxide (As2O3) could enhance the antitumor effect of radiotherapy whereas minimizing the destructive effects of radiation on bone. As2O3 treatment induced a dose-dependent (1–20 μmol/L) inhibition of endothelial and tumor cell (OSCC-3 and UM-SCC-74A) survival and significantly enhanced radiation-induced endothelial cell and tumor cell death. In contrast, As2O3 treatment (0.5–7.5 μmol/L) induced the proliferation of osteoblasts and also protected osteoblasts against radiation-induced cell death. Furthermore, As2O3 treatment was able to significantly enhance radiation-induced inhibition of endothelial cell tube formation and tumor cell colony formation. To test the effectiveness of As2O3 and radiation treatment in vivo, we used a severe combined immunodeficiency mouse model that has a bone ossicle and tumor growing side by side subcutaneously. Animals treated with As2O3 and radiation showed a significant inhibition of tumor growth, tumor angiogenesis, and tumor metastasis to the lungs as compared with As2O3 treatment or radiation treatment alone. In contrast, As2O3 treatment protected bone ossicles from radiation-induced bone loss. These results suggest a novel strategy to enhance the therapeutic efficacy of radiation treatment while protecting bone from the adverse effects of therapeutic radiation. [Mol Cancer Ther 2008;7(7):2060–9]
Down-regulation of X-linked inhibitor of apoptosis synergistically enhanced peroxisome proliferator-activated receptor γ ligand-induced growth inhibition in colon cancer
Authors: Qiao Liang , Dai Yun , Gu Qing , Chan Kwok Wah , Zou Bing , Ma Juan , Wang Jide , Lan Hui Y. , Wong Benjamin C.Y.
Published: July 2008

We found previously that X-linked inhibitor of apoptosis protein (XIAP), a potent endogenous inhibitor of apoptosis, is overexpressed in colon cancer. Ligand-induced activation of peroxisome proliferator-activated receptor γ (PPARγ) has been shown to exert proapoptotic and antiproliferative effects in many cancer cell types. However, neither XIAP down-regulation alone nor monotherapy using PPARγ ligands is potent enough to control colon cancer. We explored whether XIAP inhibition and PPARγ activation offer a synergistic anticancer effect in colon cancer. HCT116-XIAP+/+ and HCT116-XIAP-/- cells were treated with troglitazone or 15-deoxy-Δ12,14-prostaglandin J2 (15-PGJ2). Cell growth and apoptosis were measured. Nude mice were s.c. inoculated with HCT116 cells with or without oral troglitazone. Tumor growth, angiogenesis, and apoptosis were measured. Troglitazone- and 15-PGJ2-induced growth inhibition and apoptosis were more prominent in HCT116-XIAP-/- cells. Troglitazone- and 15-PGJ2-induced apoptosis correlated with enhanced cleavage of caspases and poly(ADP-ribose) polymerase, which were more profound in HCT116-XIAP-/- cells. Pretreatment of cells with XIAP inhibitor 1396-12 also sensitized HCT116-XIAP+/+ cells to PPARγ ligand-induced apoptosis. Troglitazone significantly retarded the growth of xenograft tumors, more significantly so in HCT116-XIAP-/- cell-derived tumors. Reduction of tumor size was associated with reduced expression of Ki-67, vascular endothelial growth factor, and CD31 as well as increased apoptosis. Loss of XIAP significantly sensitized colorectal cancer cells to PPARγ ligand-induced apoptosis and inhibition of cell proliferation. Thus, simultaneous inhibition of XIAP and activation of PPARγ may have a synergistic antitumor effect against colon cancer. [Mol Cancer Ther 2008;7(7):2203–11]
Signal Transducer and Activator of Transcription 3 Is Required for Hypoxia-Inducible Factor-1α RNA Expression in Both Tumor Cells and Tumor-Associated Myeloid Cells
Authors: Niu Guilian , Briggs Jon , Deng Jiehui , Ma Yihong , Lee Heehyoung , Kortylewski Marcin , Kujawski Maciej , Kay Heidi , Cress W. Douglas , Jove Richard , Yu Hua
Published: July 2008

Hypoxia-inducible factor 1 (HIF-1) is a potent tumorigenic factor. Its α subunit (HIF-1α), which is tightly regulated in normal tissues, is elevated in tumors due to hypoxia and overactive growth signaling pathways. Although much is known about HIF-1α regulation in cancer cells, crucial molecular targets that affect HIF-1α levels modulated by both hypoxia and oncogenic signaling pathways remain to be identified. Additionally, whether and how the tumor microenvironment contributes to HIF-1α accumulation is unclear. This study shows a novel mechanism by which HIF-1α availability is regulated in both cancer cells and in myeloid cells in the tumor microenvironment. We show a requirement of signal transducer and activator of transcription 3 (Stat3) for HIF-1α RNA expression under both hypoxia and growth signaling conditions. Furthermore, tumor-derived myeloid cells express elevated levels of HIF-1α mRNA relative to their counterparts from normal tissues in a Stat3-dependent manner. Additionally, Stat3 activity in the nontransformed cells in the tumor milieu affects HIF-1α RNA expression of the entire growing tumor. Consistent with a role of Stat3 in regulating HIF-1α RNA transcription, elevated Stat3 activity increases HIF-1α promoter activity, and Stat3 protein binds to the HIF-1α promoter in both transformed cells and in growing tumors. Taken together, these findings show a novel mode by which HIF-1α is regulated not only in cancer cells but also in the tumor-associated inflammatory cells, suggesting Stat3 as an important molecular target for inhibiting the oncogenic potential of HIF-1 induced by both hypoxia and overactive growth signaling pathways prevalent in cancer. (Mol Cancer Res 2008;6(7):1099–105)
Gain-of-Function Mutations in the Extracellular Domain of KIT Are Common in Canine Mast Cell Tumors
Authors: Letard Sébastien , Yang Ying , Hanssens Katia , Palmérini Fabienne , Leventhal Phillip S. , Guéry Stéphanie , Moussy Alain , Kinet Jean-Pierre , Hermine Olivier , Dubreuil Patrice
Published: July 2008

In the current study, we examined the types and frequency of KIT mutations in mast cell tumors from 191 dogs. Sequencing of reverse transcription-PCR products revealed alterations in 50 (26.2%) of the dogs. Most mutations were in exon 11 (n = 32), and of these, most were internal tandem duplications (n = 25) between residues 571 and 590. Within exon 11, there were two hotspots for mutations at codons 555-559 and 571-590. In addition, nine dogs had mutations in exon 8 and eight had mutations in exon 9. We selected the two most common mutants and two representative exon 11 mutants for further analysis. When expressed in Ba/F3 cells, they were constitutively tyrosine phosphorylated and induced growth factor–independent cell proliferation. AG1296, a tyrosine kinase inhibitor, dose dependently inhibited both the tyrosine phosphorylation of these mutants and their induction of growth factor–independent proliferation. This study shows that activating mutations in not only exon 11 but also exons 8 and 9 are common in canine mast cell tumors. These results also show that Ba/F3 cells can be used for the direct characterization of canine KIT mutants, eliminating the need to make equivalent mutations in the mouse or human genes. (Mol Cancer Res 2008;6(7):1137–45)
‘Preemptive Hydrocelectomy’ in Subinguinal Varicocelectomy
Authors: Castagnetti Marco , Cimador Marcello , DiPace Maria Rita , Catalano Pieralba , DeGrazia Enrico
Published: July 2008

Background/Aims: The hydrocele rate is very low after microsurgical subinguinal varicocelectomy, but microsurgical expertise is not always available in pediatric centers. We describe a modified technique to reduce the hydrocele rate after subinguinal varicocelectomy performed without an operating microscope. Methods: A retrospective review was performed of 142 non-microsurgical subinguinal varicocelectomies performed at a single pediatric center. In 96 patients, varicocelectomy was combined with the excision and eversion of the tunica vaginalis (‘pre-emptive hydrocelectomy’) while in the remaining 46 cases the vaginalis was left untouched. Results: Pre-emptive hydrocelectomy allowed a significant reduction in the hydrocele rate in comparison to cases in whom the vaginalis was left untouched, hydrocele rate 4.3 vs. 13% (p = 0.04). In patients undergoing preemptive hydrocelectomy, hydrocele occurred in 3 of 54 (5.5%) cases in whom the vaginalis was only excised and only 1 of 42 (2.4%) in whom it was also everted. No testicular complications were observed. Conclusions: In centers performing subinguinal varicocelectomy without the aid of an operating microscope, preemptive hydrocelectomy with eversion of the vaginalis might be offered as an adjunctive treatment with limited associated morbidity that might be able to reduce the incidence of postoperative hydrocele.
Value of Immediate Anastomotic Biopsy following Biochemical Failure after Radical Prostatectomy
Authors: Anagnostou Theodore , Sofras Frank , Melekos Michael D. , Pantazopoulos Demetrios , Lykourinas Michael , Giannopoulos Aristeides , Djavan Bob
Published: July 2008

Aims: To study the value, in diagnostic terms, of performing transrectal ultrasound (TRUS)-guided anastomotic biopsy immediately following the diagnosis of biochemical failure in patients treated by radical retropubic prostatectomy. Methods: We report on 50 sessions of TRUS-guided biopsy obtained during post-radical retropubic prostatectomy follow-up, immediately after the diagnosis of biochemical failure. No patient had received either adjuvant or further treatment due to biochemical failure status prior to the biopsy session. In each case, tissue sampling involved cores taken by a standard protocol (random) as well as TRUS-guided biopsy to sonographically suspicious areas. Statistical analysis focused on identifying the statistical importance of various pre- and post-treatment variables in predicting biopsy outcome. Results: 10/50 cases with local evidence of malignancy (1 case harboring both benign and malignant glands) were identified and in another 10/50 cases benign prostatic tissue was diagnosed. The remaining (30) cases have shown fibromuscular tissue only. Statistical analysis of various parameters has demonstrated a significant correlation between local evidence of cancer and the finding of sonographically remarkable areas. Conclusion: Performing TRUS-guided anastomotic biopsy close to the onset of biochemical failure can frequently identify but also may easily miss the suspected local presence of prostate tissue. We believe that, with minimal risks of morbidity, there is merit in exploring its possibilities to trace local prostatic tissue, since it may provide useful information for further treatment actions also in an earlier time.
Is There Any Clinical Parameter Able to Predict Prostate Cancer after Initial Diagnosis of Atypical Small Acinar Proliferation?
Authors: Mearini Luigi , Costantini Elisabetta , Bellezza Guido , Cavaliere Antonio , Zucchi Alessandro , Bini Vittorio , Porena Massimo
Published: July 2008

Introduction: Tissue samples from prostate biopsy may contain atypical small acinar proliferation (ASAP): present guidelines recommend a repeat biopsy policy. This study attempted to identify clinical patterns that help predict cancer detection at second biopsy. Materials and Methods: From 1999 to 2005, 1,274 patients underwent a prostate biopsy: in 5.9% ASAP was found, and patients underwent a second biopsy. Uni- and multivariate analysis compared the clinical patterns of cancer patients with the no cancer group at second biopsy. Results: Univariate analysis showed significant differences in PSA ratio density, prostate volume, final PSA values and ΔPSA; at multivariate logistic regression analysis, only PSA ratio (OR = 0.743, 95% CI 0.620–0.891) and prostate volume (OR = 0.960, 95% CI 0.924–0.998) were predictive of malignancy. Conclusions: In our experience, PSA ratio and prostate volume seem to be independent predictors of prostate cancer at re-biopsy.
Prevalence and Associated Factors of Day Wetting and Combined Day and Night Wetting
Authors: Toktamis Aydın , Demirel Yeltekin , Ozkan Keramettin Ugur , Garipardıç Mesut , Gözüküçük Ali , Nur Naim
Published: July 2008

Background: This study was conducted to determine the prevalence of diurnal enuresis (DE) and its association with background variables among children aged 5–15 years living in Sivas and Kahramanmaraş, Turkey. Methods: The parents of 1,760 children voluntarily completed a questionnaire consisting of 42 items under supervision of a researcher. Results: Overall, the reported prevalence of DE was 4.2%, with a tendency to decrease with increasing age and with no difference between genders. Smoking during pregnancy, delayed initiation and dealing with the child by punishment in toilet training, urination frequency, urgency, soiling, arousal difficulty, urinary infection history, lower school performance, poor social adaptation, wetting history in the family, were all significantly prevalent among diurnal enuretics (p < 0.05). Socioeconomic or sociodemographic factors based on families and stressful life events were not associated with DE (p > 0.05). 63.9% of all parents reported some level of concern about the wetting problem and 51.7% of the diurnal enuretics had previously visited a physician. Conclusions: The prevalence of DE in our sample is not too different from the prevalence rates reported previously from Turkey and other countries. This type of enuresis seems to be more associated with an organic neurological or urological disorder than is nocturnal enuresis.