bluuebunny/crossref_metadata_2025 huggingface dataset:
Data from Combinations of DNA Methyltransferase and Histone Deacetylase Inhibitors Induce DNA Damage in Small Cell Lung Cancer Cells: Correlation of Resistance with IFN-Stimulated Gene Expression
Authors: Luszczek Wioleta , Cheriyath Venugopalan , Mekhail Tarek M. , Borden Ernest C.
Published: April 2023

Abstract
Because epigenetic inhibitors can reduce cancer cell proliferation, we tested the hypothesis that concurrent inhibition of histone acetylation and DNA methylation could synergistically reduce the viability of small cell lung cancer (SCLC) cells. Sub-IC50 concentrations of the DNA methyltransferase (DNMT) inhibitor decitabine (5-AZA-dC) and the histone deacetylase (HDAC) inhibitors (LBH589 or MGCD0103) synergistically reduced the proliferation of five of nine SCLC cell lines. Loss of viability of sensitive SCLC cells did not correlate with the inhibition of either DNMT1 or HDACs, suggesting nonepigenetic mechanisms for synergy between these two classes of epigenetic modulators. Because combinations of 5-AZA-dC and HDAC inhibitors had marginal effects on the apoptosis index, Comet assay was undertaken to assess DNA damage. MGCD0103 and 5AZA-dC cotreatment augmented DNA damage in SCLC cells, resulting in increased tail length and moment in Comet assays by 24 hours in sensitive cell lines (P < 0.01). Consistent with augmented DNA damage, combination of a DNMT and HDAC inhibitor markedly increased the levels of phospho-H2A.X in sensitive cells but not in resistant ones. Comparison of basal gene expression between resistant and sensitive cells identified markedly higher basal expression of IFN-stimulated genes in the resistant cell lines, suggesting that IFN-stimulated gene expression may determine SCLC cell sensitivity to epigenetic modulators or other DNA damaging agents. Mol Cancer Ther; 9(8); 2309–21. ©2010 AACR.
Data from Experimental cancer therapy using restoration of NAD+-linked 15-hydroxyprostaglandin dehydrogenase expression
Authors: Kaliberova Lyudmila N. , Kusmartsev Sergei A. , Krendelchtchikova Valentina , Stockard Cecil R. , Grizzle William E. , Buchsbaum Donald J. , Kaliberov Sergey A.
Published: April 2023

Abstract
Preclinical and clinical evidence shows that cyclooxygenase-2 (Cox-2)-mediated prostaglandin E2 (PGE2) overexpression plays an important role in tumor growth, metastasis, and immunosuppression. It has been shown that expression of NAD+-linked 15-hydroxyprostaglandin dehydrogenase (15-PGDH), a key enzyme responsible for PGE2 inactivation, is suppressed in the majority of cancers, including breast and colon carcinoma. We have developed adenoviral vectors (Ad) encoding the 15-PGDH gene under control of the vascular endothelial growth factor receptor 1 (VEGFR1/flt-1; Adflt-PGDH) and the Cox-2 (Adcox-PGDH) promoters. The purpose of this study was to investigate cytotoxicity in vitro and therapeutic efficacy in vivo of 15-PGDH–mediated cancer therapy. The levels of PGE2 and VEGF expression were correlated with PGE2 receptor and Cox-2 and flt-1 expression in cancer cells. The in vitro study showed that Ad-mediated 15-PGDH expression significantly decreased proliferation and migration of cancer cells. Animal breast and colon tumor therapy studies showed that 15-PGDH gene therapy produced a significant delay in 2LMP and LS174T tumor growth. Combined therapy using 15-PGDH and anti-VEGF antibody (bevacizumab) significantly increased inhibition of growth of LS174T tumor xenografts in comparison with agents alone. These results suggest that 15-PGDH–mediated regulation of PGE2 catabolism in the tumor microenvironment represents a novel approach for therapy of human breast and colon cancer. [Mol Cancer Ther 2009;8(11):3130–9]
Data from The Use of One-Bead One-Compound Combinatorial Library Technology to Discover High-Affinity αvβ3 Integrin and Cancer Targeting Arginine-Glycine-Aspartic Acid Ligands with a Built-in Handle
Authors: Xiao Wenwu , Wang Yan , Lau Edmond Y. , Luo Juntao , Yao Nianhuan , Shi Changying , Meza Leah , Tseng Harry , Maeda Yoshiko , Kumaresan Pappanaicken , Liu Ruiwu , Lightstone Felice C. , Takada Yoshikazu , Lam Kit S.
Published: April 2023

Abstract
The αvβ3 integrin, expressed on the surface of various normal and cancer cells, is involved in numerous physiologic processes such as angiogenesis, apoptosis, and bone resorption. Because this integrin plays a key role in angiogenesis and metastasis of human tumors, αvβ3 integrin ligands are of great interest to advances in targeted therapy and cancer imaging. In this report, one-bead one-compound (OBOC) combinatorial libraries containing the arginine-glycine-aspartic acid (RGD) motif were designed and screened against K562 myeloid leukemia cells that had been transfected with the human αvβ3 integrin gene. Cyclic peptide LXW7 was identified as a leading ligand with a built-in handle that binds specifically to αvβ3 and showed comparable binding affinity (IC50 = 0.68 ± 0.08 μmol/L) to some of the well-known RGD “head-to-tail” cyclic pentapeptide ligands reported in the literature. The biotinylated form of LXW7 ligand showed similar binding strength as LXW7 against αvβ3 integrin, whereas biotinylated RGD cyclopentapeptide ligands revealed a 2- to 8-fold weaker binding affinity than their free forms. LXW7 was able to bind to both U-87MG glioblastoma and A375M melanoma cell lines, both of which express high levels of αvβ3 integrin. In vivo and ex vivo optical imaging studies with the biotinylated ligand/streptavidin-Cy5.5 complex in nude mice bearing U-87MG or A375M xenografts revealed preferential uptake of biotinylated LXW7 in tumor. When compared with biotinylated RGD cyclopentapeptide ligands, biotinylated LXW7 showed higher tumor uptake but lower liver uptake. Mol Cancer Ther; 9(10); 2714–23. ©2010 AACR.
Data from Chk1 and Chk2 are differentially involved in homologous recombination repair and cell cycle arrest in response to DNA double-strand breaks induced by camptothecins
Authors: Huang Min , Miao Ze-Hong , Zhu Hong , Cai Yu-Jun , Lu Wei , Ding Jian
Published: April 2023

Abstract
Camptothecins (CPT) activate S or G2-M arrest and the homologous recombination (HR) repair pathway in tumor cells. In this process, both checkpoint kinases 1 and 2 (Chk1 and Chk2, respectively) are activated, but their differential roles, especially in the coordination of checkpoint and repair control, and potential clinic relevance remain to be fully elucidated. In this study, the repairable double-strand breaks were induced in human colon cancer HCT116 cells by 1-h exposure to 25 or 100 nmol/L CPT and its novel derivative chimmitecan. The cellular disposal of double-strand breaks was reflected as the progressive dispersal of γ-H2AX foci, reduction of “comet” tails, dynamic activation of RAD51-mediated HR repair, and reversible G2-M arrest. In this model, the differential kinetics of Chk1 and Chk2 activation was characterized by the progressively increased phosphorylation of Chk2 until 72 h, the degradation of Chk1, and the disappearance of phosphorylated Chk1 48 h after drug removal. Using RNA interference, we further showed that Chk2 was essential to G2-M arrest, whereas Chk1 was mainly required for HR repair in CPT-treated HCT116 cells. Moreover, Chk2, rather than Chk1, predominated over the control of cell survival in this model. The differential roles of Chk1 and Chk2 in regulating HR repair and G2-M phase arrest were also confirmed in HT-29 colon cancer cells. Together, these findings systematically dissect the differential roles of Chk1 and Chk2 in a favorable model pursuing CPT-driven DNA damage responses, providing critical evidence to further explore checkpoint modulation, especially Chk2 inhibition as a therapeutic strategy in combination with CPT. [Mol Cancer Ther 2008;7(6):1440–9]
Data from Molecular Evolutionary Analysis of Cancer Cell Lines
Authors: Zhang Yan , Italia Michael J. , Auger Kurt R. , Halsey Wendy S. , Van Horn Stephanie F. , Sathe Ganesh M. , Magid-Slav Michal , Brown James R. , Holbrook Joanna D.
Published: April 2023

Abstract
With genome-wide cancer studies producing large DNA sequence data sets, novel computational approaches toward better understanding the role of mutations in tumor survival and proliferation are greatly needed. Tumors are widely viewed to be influenced by Darwinian processes, yet molecular evolutionary analysis, invaluable in other DNA sequence studies, has seen little application in cancer biology. Here, we describe the phylogenetic analysis of 353 cancer cell lines based on multiple sequence alignments of 3,252 nucleotides and 1,170 amino acids built from the concatenation of variant codons and residues across 494 and 523 genes, respectively. Reconstructed phylogenetic trees cluster cell lines by shared DNA variant patterns rather than cancer tissue type, suggesting that tumors originating from diverse histologies have similar oncogenic pathways. A well-supported clade of 91 cancer cell lines representing multiple tumor types also had significantly different gene expression profiles from the remaining cell lines according to statistical analyses of mRNA microarray data. This suggests that phylogenetic clustering of tumor cell lines based on DNA variants might reflect functional similarities in cellular pathways. Positive selection analysis revealed specific DNA variants that might be potential driver mutations. Our study shows the potential role of molecular evolutionary analyses in tumor classification and the development of novel anticancer strategies. Mol Cancer Ther; 9(2); 279–91
Data from WIF1, a Wnt pathway inhibitor, regulates SKP2 and c-myc expression leading to G1 arrest and growth inhibition of human invasive urinary bladder cancer cells
Authors: Tang Yaxiong , Simoneau Anne R. , Liao Wu-xiang , Yi Guo , Hope Christopher , Liu Feng , Li Shunqiang , Xie Jun , Holcombe Randall F. , Jurnak Frances A. , Mercola Dan , Hoang Bang H. , Zi Xiaolin
Published: April 2023

Abstract
Epigenetic silencing of secreted wingless-type (Wnt) antagonists through hypermethylation is associated with tobacco smoking and with invasive bladder cancer. The secreted Wnt inhibitory factor-1 (WIF1) has shown consistent growth-inhibitory effect on various cancer cell lines. Therefore, we assessed the mechanisms of action of WIF1 by either restoring WIF1 expression in invasive bladder cancer cell lines (T24 and TSU-PR1) or using a recombinant protein containing functional WIF1 domain. Both ectopic expression of WIF1 and treatment with WIF1 domain protein resulted in cell growth inhibition via G1 arrest. The G1 arrest induced by WIF1 is associated with down-regulation of SKP2 and c-myc and up-regulation of p21/WAF1 and p27/Kip1. Conversely, reexpression of SKP2 in WIF1-overexpressing TSU-PR1 cells attenuated the WIF1-induced G1 arrest. Furthermore, inhibition of nuclear Wnt signaling by either dominant-negative LEF1 or short hairpin RNA of TCF4 also reduced SKP2 expression. The human SKP2 gene contains two TCF/LEF1 consensus binding sites within the promoter. Chromatin immunoprecipitation/real-time PCR analysis revealed that both WIF1 and dominant-negative LEF1 expression decreased the in vivo binding of TCF4 and β-catenin to the SKP2 promoter. Together, our results suggest that mechanisms of WIF1-induced G1 arrest include (a) SKP2 down-regulation leading to p27/Kip1 accumulation and (b) c-myc down-regulation releasing p21/WAF1 transcription. Additionally, we show that WIF1 inhibits in vivo bladder tumor growth in nude mice. These observations suggest a mechanism for transformation of bladder epithelium on loss of WIF1 function and provide new targets such as SKP2 for intervention in WIF1-deficient bladder cancer. [Mol Cancer Ther 2009;8(2):458–68]
Data from Subcellular Distribution of a Fluorescence-Labeled Combi-Molecule Designed to Block Epidermal Growth Factor Receptor Tyrosine Kinase and Damage DNA with a Green Fluorescent Species
Authors: Todorova Margarita I. , Larroque Anne-Laure , Dauphin-Pierre Sabine , Fang You-Qiang , Jean-Claude Bertrand J.
Published: April 2023

Abstract
To monitor the subcellular distribution of mixed epidermal growth factor (EGF) receptor (EGFR)–DNA targeting drugs termed combi-molecules, we designed AL237, a fluorescent prototype, to degrade into a green fluorescent DNA damaging species and FD105, a blue fluorescent EGFR inhibitor. Here we showed that AL237 damaged DNA in the 12.5 to 50 μmol/L range. Despite its size, it blocked EGFR phosphorylation in an enzyme assay (IC50 = 0.27 μmol/L) and in MDA-MB468 breast cancer cells in the same concentration range as for DNA damage. This translated into inhibition of extracellular signal-regulated kinase 1/2 or BAD phosphorylation and downregulation of DNA repair proteins (XRCC1, ERCC1). Having shown that AL237 was a balanced EGFR-DNA targeting molecule, it was used as an imaging probe to show that (a) green and blue colors were primarily colocalized in the perinuclear and partially in the nucleus in EGFR- or ErbB2-expressing cells, (b) the blue fluorescence associated with FD105, but not the green, was colocalized with anti-EGFR red-labeled antibody, (c) the green fluorescence of nuclei was significantly more intense in NIH 3T3 cells expressing EGFR or ErbB2 than in their wild-type counterparts (P < 0.05). Similarly, the growth inhibitory potency of AL237 was selectively stronger in the transfectants. In summary, the results suggest that AL237 diffuses into the cells and localizes abundantly in the perinuclear region and partially in the nucleus where it degrades into EGFR and DNA targeting species. This bystander-like effect translates into high levels of DNA damage in the nucleus. Sufficient quinazoline levels are released in the cells to block EGF-induced activation of downstream signaling. Mol Cancer Ther; 9(4); 869–82. ©2010 AACR.
Data from Gene expression profiles do not consistently predict the clinical treatment response in locally advanced breast cancer
Authors: Sørlie Therese , Perou Charles M. , Fan Cheng , Geisler Stephanie , Aas Turid , Nobel Andrew , Anker Gun , Akslen Lars A. , Botstein David , Børresen-Dale Anne-Lise , Lønning Per Eystein
Published: April 2023

Abstract
Neoadjuvant treatment offers an opportunity to correlate molecular variables to treatment response and to explore mechanisms of drug resistance in vivo. Here, we present a statistical analysis of large-scale gene expression patterns and their relationship to response following neoadjuvant chemotherapy in locally advanced breast cancers. We analyzed cDNA expression data from 81 tumors from two patient series, one treated with doxorubicin alone (51) and the other treated with 5-fluorouracil and mitomycin (30), and both were previously studied for correlations between TP53 status and response to therapy. We observed a low frequency of progressive disease within the luminal A subtype from both series (2 of 36 versus 13 of 45 patients; P = 0.0089) and a high frequency of progressive disease among patients with luminal B type tumors treated with doxorubicin (5 of 8 patients; P = 0.0078); however, aside from these two observations, no other consistent associations between response to chemotherapy and tumor subtype were observed. These specific associations could possibly be explained by covariance with TP53 mutation status, which also correlated with tumor subtype. Using supervised analysis, we could not uncover a gene profile that could reliably (>70% accuracy and specificity) predict response to either treatment regimen. [Mol Cancer Ther 2006;5(11):2914–8]
Data from Analysis of Food and Drug Administration–Approved Anticancer Agents in the NCI60 Panel of Human Tumor Cell Lines
Authors: Holbeck Susan L. , Collins Jerry M. , Doroshow James H.
Published: April 2023

Abstract
Since the early 1990s the Developmental Therapeutics Program of the National Cancer Institute (NCI) has utilized a panel of 60 human tumor cell lines (NCI60) representing 9 tissue types to screen for potential new anticancer agents. To date, about 100,000 compounds and 50,000 natural product extracts have been screened. Early in this program it was discovered that the pattern of growth inhibition in these cell lines was similar for compounds of similar mechanism. The development of the COMPARE algorithm provided a means by which investigators, starting with a compound of interest, could identify other compounds whose pattern of growth inhibition was similar. With extensive molecular characterization of these cell lines, COMPARE and other user-defined algorithms have been used to link patterns of molecular expression and drug sensitivity. We describe here the results of screening current Food and Drug Administration (FDA)-approved anticancer agents in the NCI60 screen, with an emphasis on those agents that target signal transduction. We analyzed results from agents with mechanisms of action presumed to be similar; we also carried out a hierarchical clustering of all of these agents. The addition of data from recently approved anticancer agents will increase the utility of the NCI60 databases to the cancer research community. These data are freely accessible to the public on the DTP website (http://dtp.cancer.gov/). The FDA-approved anticancer agents are themselves available from the NCI as a plated set of compounds for research use. Mol Cancer Ther; 9(5); 1451–60. ©2010 AACR.
Data from Antiangiogenic Activity of a Neutralizing Human Single-Chain Antibody Fragment against Fibroblast Growth Factor Receptor 1
Authors: Ronca Roberto , Benzoni Patrizia , Leali Daria , Urbinati Chiara , Belleri Mirella , Corsini Michela , Alessi Patrizia , Coltrini Daniela , Calza Stefano , Presta Marco , Dell'Era Patrizia
Published: April 2023

Abstract
Fibroblast growth factor receptor-1 (FGFR-1) transduces proangiogenic and proliferative signals in human cancers. Thus, FGFR-1 may represent a target for the development of antiangiogenic/antineoplastic therapies. We screened a human single-chain fragment variable (scFv) antibody phage display library against the extracellular domain of the FGFR-1-IIIc isoform that harbors the FGF binding site. Several phages were isolated and tested for specificity and sensitivity, and the most promising antibody fragment RR-C2 was characterized for its biochemical and biological properties. ScFv RR-C2 specifically recognizes FGFR-1α and FGFR-1β isoforms in ELISA, Western blotting, and surface plasmon resonance analysis with a Kd value of 300 and 144 nmol/L for the 2 receptor isoforms, respectively. The antibody fragment also recognizes FGFR-1 when the receptor is exposed on the cell surface, thus preventing the formation of the ternary complex among FGFR-1, its ligand FGF2, and cell surface heparan sulfate proteoglycans. Accordingly, scFv RR-C2 specifically inhibits FGF2-mediated mitogenic activity in endothelial cells of human, bovine, and murine origin in a nanomolar range of concentrations. Also, the antibody fragment prevents FGF2-triggered sprouting of both human umbilical vein endothelial cell spheroids and of murine endothelium from aortic rings. Finally, the antibody fragment hampers the angiogenic activity exerted both by FGF2 in the chick embryo chorioallantoic membrane assay and by S115 mouse mammary tumor cells in the Matrigel plug assay. Taken together, the data show that scFv RR-C2 recognizes and neutralizes FGFR-1 activity in different animal species, including humans, thus representing a novel tool for the development of antiangiogenic/antineoplastic therapies. Mol Cancer Ther; 9(12); 3244–53. ©2010 AACR.
Data from Identification of Common Predictive Markers of In vitro Response to the Mek Inhibitor Selumetinib (AZD6244; ARRY-142886) in Human Breast Cancer and Non–Small Cell Lung Cancer Cell Lines
Authors: Garon Edward B. , Finn Richard S. , Hosmer Wylie , Dering Judy , Ginther Charles , Adhami Shahriar , Kamranpour Naeimeh , Pitts Sharon , Desai Amrita , Elashoff David , French Tim , Smith Paul , Slamon Dennis J.
Published: April 2023

Abstract
Selumetinib (AZD6244; ARRY-142886) is a tight-binding, uncompetitive inhibitor of mitogen-activated protein kinase kinases (MEK) 1 and 2 currently in clinical development. We evaluated the effects of selumetinib in 31 human breast cancer cell lines and 43 human non–small cell lung cancer (NSCLC) cell lines to identify characteristics correlating with in vitro sensitivity to MEK inhibition. IC50 <1 μmol/L (considered sensitive) was seen in 5 of 31 breast cancer cell lines and 15 of 43 NSCLC cell lines, with a correlation between sensitivity and raf mutations in breast cancer cell lines (P = 0.022) and ras mutations in NSCLC cell lines (P = 0.045). Evaluation of 27 of the NSCLC cell lines with Western blots showed no clear association between MEK and phosphoinositide 3-kinase pathway activation and sensitivity to MEK inhibition. Baseline gene expression profiles were generated for each cell line using Agilent gene expression arrays to identify additional predictive markers. Genes associated with differential sensitivity to selumetinib were seen in both histologies, including a small number of genes in which differential expression was common to both histologies. In total, these results suggest that clinical trials of selumetinib in breast cancer and NSCLC might select patients whose tumors harbor raf and ras mutations, respectively. Mol Cancer Ther; 9(7); 1985–94. ©2010 AACR.
Data from Targeting both HIF-1 and HIF-2 in human colon cancer cells improves tumor response to sunitinib treatment
Authors: Burkitt Kyunghee , Chun Sang Y. , Dang Duyen T. , Dang Long H.
Published: April 2023

Abstract
Sunitinib is an oral small-molecule multitargeted receptor tyrosine kinase inhibitor that has recently been shown to have clinical benefit as a single agent in renal cell cancer and gastrointestinal stromal tumors, leading to its Food and Drug Administration approval for treatment of these cancers. However, the benefit is short-lived; and for the majority of cancers, sunitinib single-agent clinical activity is low. Therefore, combination strategies with sunitinib are currently in clinical development. The hypoxia-inducible transcription factors, HIF-1 and HIF-2, induce gene programs important for cancer cell growth and angiogenesis. We hypothesized that inhibiting HIF-1 and HIF-2 would further improve tumor response to sunitinib therapy. To test this hypothesis, HIF-1α and HIF-2α genes were disrupted in colon cancer cells. We found that disruption of HIF-1α, HIF-2α, or both HIF-1α and HIF-2α genes led to improved tumor response to sunitinib. For xenografts in which both HIF-1α and HIF-2α genes were disrupted, there was prolonged complete remission with sunitinib treatment in 50% of mice. This enhanced response was mediated by two potential mechanisms. First, tumor angiogenesis and perfusion were almost completely inhibited by sunitinib when both HIF-1α and HIF-2α genes were disrupted. The enhanced inhibitory effect on tumor angiogenesis was mediated by the inhibition of multiple proangiogenic factors, including vascular endothelial growth factor and angiopoietin-like protein 4, and the induction of the antiangiogenic factor, thrombospondin 1. Second, disruption of HIF-1α, HIF-2α, or both HIF-1α and HIF-2α genes directly inhibited tumor cell proliferation. These preclinical findings have clinical implications and suggest novel clinical trials. [Mol Cancer Ther 2009;8(5):OF1–9]
Data from Synthesis and biological analysis of new curcumin analogues bearing an enhanced potential for the medicinal treatment of cancer
Authors: Ohori Hisatsugu , Yamakoshi Hiroyuki , Tomizawa Masaki , Shibuya Masatoshi , Kakudo Yuichi , Takahashi Atsuko , Takahashi Shin , Kato Satoshi , Suzuki Takao , Ishioka Chikashi , Iwabuchi Yoshiharu , Shibata Hiroyuki
Published: April 2023

Abstract
Curcumin (diferuloylmethane) is a dietary phytochemical with low toxicity that exhibits growth-suppressive activity against a variety of cancer cells and possesses certain chemopreventive properties. Curcumin has already been the subject of several clinical trials for use as a treatment in human cancers. Synthetic chemical modifications of curcumin have been studied intensively in an attempt to find a molecule with similar but enhanced properties of curcumin. In this study, a series of novel curcumin analogues were synthesized and screened for anticancer activity. New analogues that exhibit growth-suppressive activity 30 times that of curcumin and other commonly used anticancer drugs were identified. Structurally, the new analogues are symmetrical 1,5-diarylpentadienone whose aromatic rings possess an alkoxy substitution at each of the positions 3 and 5. Analysis of the effects of the analogues on the expression of cancer-related genes usually affected by curcumin indicated that some induced the down-regulation of β-catenin, Ki-ras, cyclin D1, c-Myc, and ErbB-2 at as low as one eighth the concentration at which curcumin normally has an effect. The analogues, however, exhibited neither harmful nor growth-suppressive effects on normal hepatocytes where oncogene products are not activated. They also exhibited no toxicities in vivo that they may provide effective alternative therapies for the prevention and treatment of some human cancers. [Mol Cancer Ther 2006;5(10):2563–71]
Data from Sensitivity to the Aromatase Inhibitor Letrozole Is Prolonged After a “Break” in Treatment
Authors: Sabnis Gauri , Goloubeva Olga , Gilani Rabia , Macedo Luciana , Brodie Angela
Published: April 2023

Abstract
Using a hormone-dependent xenograft model, we established that loss of response to letrozole was accompanied by upregulation of the Her-2/mitogen-activated protein kinase (MAPK) pathway and downregulation of estrogen receptor α (ERα) and aromatase activity. In our previous study, we showed that stopping letrozole treatment or adding trastuzumab could reverse acquired resistance. In this study, we compared the effects of intermittent letrozole treatment and switching treatment between letrozole and trastuzumab on tumor growth in an attempt to optimize discontinuous letrozole treatment. The mice were treated with letrozole until the tumors developed resistance and then were divided into three groups: (a) letrozole, (b) trastuzumab, and (c) “off” (Δ4A supplement only); tumors were collected every week to examine changes in tumor protein expression and activity. In off group tumors, Her-2/p-MAPK activation gradually decreased and ERα and aromatase protein (and activity) increased. Within the first week of trastuzumab treatment, Her-2 and MAPK were downregulated and ERα was upregulated. When letrozole-resistant MCF-7Ca tumors were taken off treatment for 4 weeks, the second course of letrozole treatment provided a much longer duration of response (P = 0.02). However, switching treatment to trastuzumab for 4 weeks did not provide any inhibition of tumor growth. Our studies revealed that the adaptation of cells to a low-estrogen environment by upregulation of Her-2/MAPK and downregulation of ERα/aromatase was reversed on letrozole withdrawal. The tumors once again became responsive to letrozole for a significant period. These results suggest that response to letrozole can be prolonged by a short “break” in the treatment. Mol Cancer Ther; 9(1); 46–56
Data from A Bead-Based Activity Screen for Small-Molecule Inhibitors of Signal Transduction in Chronic Myelogenous Leukemia Cells
Authors: Sylvester Juliesta E. , Kron Stephen J.
Published: April 2023

Abstract
Chronic myelogenous leukemia is characterized by the presence of the chimeric BCR-ABL gene, which is expressed as the constitutively active Bcr-Abl kinase. Although kinase activity is directly responsible for the clinical phenotype, current diagnostic and prognostic methods focus on a genetic classification system in which molecularly distinct subcategories are used to predict patient responses to small-molecule inhibitors of the Bcr-Abl kinase. Point mutations in the kinase domain are a central factor regulating inhibitor resistance; however, compensatory signaling caused by the activation of unrelated kinases can influence inhibitor efficacy. Kinase activity profiling can be used as a complementary approach to genetic screening and allows direct screening of small-molecule inhibitors. We developed a quantitative assay to monitor tyrosine kinase activities and inhibitor sensitivities in a model of chronic myelogenous leukemia using peptide reporters covalently immobilized on Luminex beads. Kinase activity is quantified by nonlinear regression from well-specific internal standard curves. Using optimized synthetic substrates and peptides derived from native substrates as probes, we measured kinase inhibition in cell lysates by the signal transduction inhibitors imatinib and dasatinib. Taking advantage of a convenient 96-well plate format, this assay also allows a straightforward and quantitative analysis of the differential effects of ATP and inhibitors on kinase activity. This method for analyzing a focused signaling network benefits from rigorous statistical analysis and short processing times, thereby offering a powerful tool for drug discovery and clinical testing. Mol Cancer Ther; 9(5); 1469–81. ©2010 AACR.
Data from PF-03814735, an Orally Bioavailable Small Molecule Aurora Kinase Inhibitor for Cancer Therapy
Authors: Jani Jitesh P. , Arcari Joel , Bernardo Vincent , Bhattacharya Samit K. , Briere David , Cohen Bruce D. , Coleman Kevin , Christensen James G. , Emerson Erling O. , Jakowski Amy , Hook Kenneth , Los Gerrit , Moyer James D. , Pruimboom-Brees Ingrid , Pustilnik Leslie , Rossi Ann Marie , Steyn Stefan J. , Su Chunyan , Tsaparikos Konstantinos , Wishka Donn , Yoon Kwansik , Jakubczak John L.
Published: April 2023

Abstract
The Aurora family of highly related serine/threonine kinases plays a key role in the regulation of mitosis. Aurora1 and Aurora2 play important but distinct roles in the G2 and M phases of the cell cycle and are essential for proper chromosome segregation and cell division. Overexpression and amplification of Aurora2 have been reported in different tumor types, including breast, colon, pancreatic, ovarian, and gastric cancer. PF-03814735 is a novel, potent, orally bioavailable, reversible inhibitor of both Aurora1 and Aurora2 kinases that is currently in phase I clinical trials for the treatment of advanced solid tumors. In intact cells, the inhibitory activity of PF-03814735 on the Aurora1 and Aurora2 kinases reduces levels of phospho-Aurora1, phosphohistone H3, and phospho-Aurora2. PF-03814735 produces a block in cytokinesis, resulting in inhibition of cell proliferation and the formation of polyploid multinucleated cells. Although PF-03814735 produces significant inhibition of several other protein kinases, the predominant biochemical effects in cellular assays are consistent with inhibition of Aurora kinases. Once-daily oral administration of PF-03814735 to mice bearing human xenograft tumors produces a reduction in phosphohistone H3 in tumors at doses that are tolerable and that result in significant inhibition of tumor growth. The combination of PF-03814735 and docetaxel in xenograft mouse tumor models shows additive tumor growth inhibition. These results support the clinical evaluation of PF-03814735 in cancer patients. Mol Cancer Ther; 9(4); 883–94. ©2010 AACR.
Data from A MicroRNA Screen to Identify Modulators of Sensitivity to BCL2 Inhibitor ABT-263 (Navitoclax)
Authors: Lam Lloyd T. , Lu Xin , Zhang Haichao , Lesniewski Rick , Rosenberg Saul , Semizarov Dimitri
Published: April 2023

Abstract
Evasion of apoptosis is a known feature of cancer cells. One mechanism of deregulating the apoptotic pathway is through overexpression of antiapoptotic BCL2 family members. ABT-263 (navitoclax) is a first-in-class BCL2 family inhibitor that restores the ability of cancer cells to undergo apoptosis. However, many cancer cells are resistant to ABT-263 due to high levels of a BCL2 family member, MCL1, which is not targeted by the drug. MCL1 expression is regulated transcriptionally, translationally, and through proteasome-mediated degradation. Recently, MCL1 expression was shown to be affected by microRNAs (miRNA). To identify miRNAs that modulate the sensitivity of cancer cells to ABT-263, we screened a library of 810 human miRNA mimics in HCT-116 cells in the presence of ABT-263. The screen revealed 19 miRNAs that sensitize HCT-116 cells to ABT-263. Fifteen of these miRNAs were also shown to sensitize CHL1 melanoma cells to the same agent. We further evaluated 12 of the strongest sensitizers in these cell lines. We found that these sensitizers induced apoptosis only in the presence of ABT-263. In addition, whereas all 12 of these miRNAs reduced MCL1 protein expression, only 10 of them targeted MCL1 through direct binding to the 3′-untranslated region of the gene, raising the possibility that other resistance regulators of MCL1 expression may be identified using our method. Finally, because sensitizing miRNA expression is lower in tumors compared with normal tissues, our data can facilitate the design of miRNA replacement therapies to increase sensitivity to BCL2 antagonists. Mol Cancer Ther; 9(11); 2943–50. ©2010 AACR.
Data from Correction for chromosome-17 is critical for the determination of true Her-2/neu gene amplification status in breast cancer
Authors: Dal Lago Lissandra , Durbecq Virginie , Desmedt Christine , Salgado Roberto , Verjat Thibault , Lespagnard Laurence , Ma Yan , Veys Isabelle , Di Leo Angelo , Sotiriou Christos , Piccart Martine , Larsimont Denis
Published: April 2023

Abstract
Purpose: Trastuzumab is the cornerstone for treatment of women with HER2-overexpressing breast cancer, both in the adjuvant and in the metastatic settings. The accurate assessment of HER2 is, therefore, critical to identifying patients who may benefit from trastuzumab-based therapy. This project aimed to determine the optimal scoring method for fluorescence in situ hybridization (FISH) assay. Methods: FISH assay was done on 893 samples of breast cancer. Three scoring methods were evaluated: Her2/CEP17≥2, Her2>4, or Her2>6. Protein and gene expression were evaluated by immunohistochemistry (n = 584) and mRNA/assay/nucleic acid sequence–based amplification (NASBA; n = 90). Results: Samples were divided into five groups based on FISH results: disomic amplified and nonamplified, polysomic amplified, nonamplified, and discordant (10.8% of cases, mostly positive with Her2>4 scoring, but negative with the others). Her2/CEP17≥2 and Her2>6 scoring methods showed the best association (a) with regard to FISH scoring (κ = 0.906, P < 10−6) and (b) between FISH and immunohistochemistry (3+ as positive; κ > 0.650, P < 10−6) or NASBA (κ > 0.536, P < 10−6). Polysomy had an effect on Her2 copy number (P < 10−6), but had no effect on protein and mRNA content. Therefore, within the discordant subgroup, for which additive Her-2 gene copies are due to high polysomy, protein and mRNA levels were similar to those of the nonamplified samples. For this subgroup, the best concordance between FISH/immunohistochemistry/NASBA was observed with the Her2/CEP17 ratio and Her-2>6 scoring (68% and 58% perfect matches, respectively). No perfect matches were observed using the Her2>4 scoring method. Conclusion: Correction for chromosome-17 is the method of choice for clinical practice; Her-2>6, but not Her-2>4, could be used as an alternative. [Mol Cancer Ther 2006;5(10):2572–9]
Data from ARC Synergizes with ABT-737 to Induce Apoptosis in Human Cancer Cells
Authors: Bhat Uppoor G. , Pandit Bulbul , Gartel Andrei L.
Published: April 2023

Abstract
Previously, we reported that the nucleoside analogue/transcriptional inhibitor ARC (4-amino-6-hydrazino-7-β-d-ribofuranosyl-7H-pyrrolo(2,3-d)-pyrimidine-5-carboxamide) was able to induce p53-independent apoptosis in multiple cancer cell lines of different origins. This occurred, at least in part, by the suppression of short-lived, prosurvival member of the Bcl-2 family, Mcl-1. In contrast, we show here that treatment of human cancer cells with the pan-Bcl-2 inhibitor ABT-737 alone led to upregulation of Mcl-1 protein expression. Combination of subapoptotic concentrations of ABT-737 and ARC induced mitochondrial injury and potent caspase-3/caspase-9–dependent apoptosis in a wide variety of human cancer cell lines. These data suggest that the ABT-737/ARC combination, which simultaneously targets Bcl-2 and Mcl-1, may be efficient against human cancer. Mol Cancer Ther; 9(6); 1688–96. ©2010 AACR.
Data from Antixenograft tumor activity of a humanized anti-insulin-like growth factor-I receptor monoclonal antibody is associated with decreased AKT activation and glucose uptake
Authors: Shang Yonglei , Mao Yifan , Batson Jennifer , Scales Suzie J. , Phillips Gail , Lackner Mark R. , Totpal Klara , Williams Simon , Yang Jihong , Tang Zhijun , Modrusan Zora , Tan Christine , Liang Wei-Ching , Tsai Siao Ping , Vanderbilt Alexander , Kozuka Kenji , Hoeflich Klaus , Tien Janet , Ross Sarajane , Li Congfen , Lee Sang Hoon , Song An , Wu Yan , Stephan Jean-Philippe , Ashkenazi Avi , Zha Jiping
Published: April 2023

Abstract
The insulin-like growth factor (IGF) system consists of two ligands (IGF-I and IGF-II), which both signal through IGF-I receptor (IGF-IR) to stimulate proliferation and inhibit apoptosis, with activity contributing to malignant growth of many types of human cancers. We have developed a humanized, affinity-matured anti-human IGF-IR monoclonal antibody (h10H5), which binds with high affinity and specificity to the extracellular domain. h10H5 inhibits IGF-IR-mediated signaling by blocking IGF-I and IGF-II binding and by inducing cell surface receptor down-regulation via internalization and degradation, with the extracellular and intracellular domains of IGF-IR being differentially affected by the proteasomal and lysosomal inhibitors. In vitro, h10H5 exhibits antiproliferative effects on cancer cell lines. In vivo, h10H5 shows single-agent antitumor efficacy in human SK-N-AS neuroblastoma and SW527 breast cancer xenograft models and even greater efficacy in combination with the chemotherapeutic agent docetaxel or an anti–vascular endothelial growth factor antibody. Antitumor activity of h10H5 is associated with decreased AKT activation and glucose uptake and a 316-gene transcription profile with significant changes involving DNA metabolic and cell cycle machineries. These data support the clinical testing of h10H5 as a biotherapeutic for IGF-IR-dependent human tumors and furthermore illustrate a new method of monitoring its activity noninvasively in vivo via 2-fluoro-2-deoxy-d-glucose-positron emission tomography imaging. [Mol Cancer Ther 2008;7(9):2599–608]
Data from Epigenetic reversal of acquired resistance to 5-fluorouracil treatment
Authors: Humeniuk Rita , Mishra Prasun J. , Bertino Joseph R. , Banerjee Debabrata
Published: April 2023

Abstract
Acquired and intrinsic resistance still remains a limitation to the clinical use of 5-fluorouracil (5-FU). The contribution of epigenetic changes to the development of drug resistance remains to be elucidated. Several genes that are hypermethylated and silenced have been identified in colorectal cancer. Based on the findings described in the accompanying article, we hypothesized that acquired resistance to “pulse” 5-FU has an epigenetic origin and might be reversed. Here, we present a novel therapeutic approach to circumvent clinical resistance to bolus 5-FU, that is, treatment of bolus 5-FU-resistant colorectal cancer cells with low-dose 5-azadeoxycytidine (DAC), an inhibitor of DNA hypermethylation, restored sensitivity to 5-FU as well as 5-fluorouridine. Moreover, treatment of nude mice bearing a 5-FU-resistant tumor, characterized by decreased levels of UMP kinase (UMPK), with DAC overcame resistance to bolus 5-FU. DAC-mediated restoration of 5-FU sensitivity was associated with increases in UMPK levels. An increase in UMPK protein and mRNA levels following treatment with low-dose DAC was observed in cultured bolus 5-FU-resistant colorectal cancer cells (HCT-8) and in mice bearing these tumors. We conclude that DAC-mediated restoration of sensitivity to bolus 5-FU is mediated at least in part by increased UMPK levels and clinical resistance to 5-FU due to decreased UMPK in colorectal cancer may be overcome by including methylation inhibitors such as DAC. [Mol Cancer Ther 2009;8(5):1045–54]
Data from The Mismatch Repair System Modulates Curcumin Sensitivity through Induction of DNA Strand Breaks and Activation of G2-M Checkpoint
Authors: Jiang Zhihua , Jin ShunQian , Yalowich Jack C. , Brown Kevin D. , Rajasekaran Baskaran
Published: April 2023

Abstract
The highly conserved mismatch (MMR) repair system corrects postreplicative errors and modulates cellular responses to genotoxic agents. Here, we show that the MMR system strongly influences cellular sensitivity to curcumin. Compared with MMR-proficient cells, isogenically matched MMR-deficient cells displayed enhanced sensitivity to curcumin. Similarly, cells suppressed for MLH1 or MSH2 expression by RNA interference displayed increased curcumin sensitivity. Curcumin treatment generated comparable levels of reactive oxygen species and the mutagenic adduct 8-oxo-guanine in MMR-proficient and MMR-deficient cells; however, accumulation of γH2AX foci, a marker for DNA double-strand breaks (DSB), occurred only in MMR-positive cells in response to curcumin treatment. Additionally, MMR-positive cells showed activation of Chk1 and induction of G2-M cell cycle checkpoint following curcumin treatment and inhibition of Chk1 by UCN-01 abrogated Chk1 activation and heightened apoptosis in MMR-proficient cells. These results indicate that curcumin triggers the accumulation of DNA DSB and induction of a checkpoint response through a MMR-dependent mechanism. Conversely, in MMR-compromised cells, curcumin-induced DSB is significantly blunted, and as a result, cells fail to undergo cell cycle arrest, enter mitosis, and die through mitotic catastrophe. The results have potential therapeutic value, especially in the treatment of tumors with compromised MMR function. Mol Cancer Ther; 9(3); 558–68
Data from Combination of Two Insulin-Like Growth Factor-I Receptor Inhibitory Antibodies Targeting Distinct Epitopes Leads to an Enhanced Antitumor Response
Authors: Dong Jianying , Demarest Stephen J. , Sereno Arlene , Tamraz Susan , Langley Emma , Doern Adam , Snipas Tracey , Perron Keli , Joseph Ingrid , Glaser Scott M. , Ho Steffan N. , Reff Mitchell E. , Hariharan Kandasamy
Published: April 2023

Abstract
The insulin-like growth factor-I receptor (IGF-IR) is a cell surface receptor tyrosine kinase that mediates cell survival signaling and supports tumor progression in multiple tumor types. We identified a spectrum of inhibitory IGF-IR antibodies with diverse binding epitopes and ligand-blocking properties. By binding distinct inhibitory epitopes, two of these antibodies, BIIB4 and BIIB5, block both IGF-I and IGF-II binding to IGF-IR using competitive and allosteric mechanisms, respectively. Here, we explored the inhibitory effects of combining BIIB4 and BIIB5. In biochemical assays, the combination of BIIB4 and BIIB5 improved both the potency and extent of IGF-I and IGF-II blockade compared with either antibody alone. In tumor cells, the combination of BIIB4 and BIIB5 accelerated IGF-IR downregulation and more efficiently inhibited IGF-IR activation as well as downstream signaling, particularly AKT phosphorylation. In several carcinoma cell lines, the antibody combination more effectively inhibited ligand-driven cell growth than either BIIB4 or BIIB5 alone. Notably, the enhanced tumor growth–inhibitory activity of the BIIB4 and BIIB5 combination was much more pronounced at high ligand concentrations, where the individual antibodies exhibited substantially reduced activity. Compared with single antibodies, the BIIB4 and BIIB5 combination also significantly further enhanced the antitumor activity of the epidermal growth factor receptor inhibitor erlotinib and the mTOR inhibitor rapamycin. Moreover, in osteosarcoma and hepatocellular carcinoma xenograft models, the BIIB4 and BIIB5 combination significantly reduced tumor growth to a greater degree than each single antibody. Taken together, our results suggest that targeting multiple distinct inhibitory epitopes on IGF-IR may be a more effective strategy of affecting the IGF-IR pathway in cancer. Mol Cancer Ther; 9(9); 2593–604. ©2010 AACR.
Data from Hypoxia prevents etoposide-induced DNA damage in cancer cells through a mechanism involving hypoxia-inducible factor 1
Authors: Sullivan Richard , Graham Charles H.
Published: April 2023

Abstract
Intratumoral hypoxia is associated with resistance to therapy in many human cancers, and preexposure of tumor cells to hypoxia confers multidrug resistance. Whereas most anticancer drugs kill proliferating tumor cells by causing DNA damage, a role for hypoxia in the prevention and/or repair of drug-induced DNA damage has not been clear. Using the alkaline comet assay, we provide direct evidence that hypoxia-induced resistance to etoposide in human tumor cells (MDA-MB-231 breast carcinoma and DU-145 prostatic adenocarcinoma) is mainly due to prevention of drug-induced DNA damage (i.e., strand breaks) and that the amount of DNA damage present immediately after etoposide exposure is a good independent predictor of clonogenic survival. Our results also revealed that preexposure to hypoxia did not affect the apparent DNA repair capacity of cells. These findings indicate that the extent of DNA damage resulting from etoposide exposure is a more important determinant of survival than subsequent events after DNA damage. Furthermore, immunofluorescence analysis showed that, in a subpopulation of cells, preexposure to hypoxia decreased the levels of topoisomerase IIα, an enzyme that generates DNA strand breaks when poisoned with etoposide. Treatment of cells with small interfering RNA targeting hypoxia-inducible factor 1 prevented the hypoxia-induced decreases in topoisomerase IIα levels, abolished the protective effect of hypoxia against etoposide-induced DNA damage, and inhibited hypoxia-induced etoposide resistance. These findings support a model of hypoxia-induced drug resistance in which etoposide-induced DNA damage is prevented by HIF-1–dependent adaptations to hypoxia. [Mol Cancer Ther 2009;8(6):1702–13]
Data from Effective gene-viral therapy of leukemia by a new fiber chimeric oncolytic adenovirus expressing TRAIL: in vitro and in vivo evaluation
Authors: Jin Jie , Liu Hui , Yang Chunmei , Li Gongchu , Liu Xinyuan , Qian Qijun , Qian Wenbin
Published: April 2023

Abstract
Conditionally replicating adenoviruses (CRAd) have been under extensive investigations as anticancer agents. Previously, we found that ZD55, an adenovirus serotype 5-based CRAd, infected and killed the leukemia cells expressing coxsackie adenovirus receptor (CAR). However, majority of leukemic cells lack CAR expression on their cell surface, resulting in resistance to CRAd infection. In this study, we showed that SG235, a novel fiber chimeric CRAd that has Ad35 tropism, permitted CAR-independent cell entry, and this in turn produced selective cytopathic effects in a variety of human leukemic cells in vitro and in vivo. Moreover, SG235 expressing exogenous tumor necrosis factor-related apoptosis-inducing ligand (SG235-TRAIL) effectively induced apoptosis of leukemic cells via the activation of extrinsic and intrinsic apoptotic pathway and elicited a superior antileukemia activity compared with SG235. In addition, normal hematopoietic progenitors were resistant to the inhibitory activity of SG235 and SG235-TRAIL. Our data suggest that these novel oncolytic agents may serve as useful tools for the treatment of leukemia. [Mol Cancer Ther 2009;8(5):1387–97]