bluuebunny/crossref_metadata_2025 huggingface dataset:
Data from Combination of EGFR and MEK1/2 inhibitor shows synergistic effects by suppressing EGFR/HER3-dependent AKT activation in human gastric cancer cells
Authors: Yoon Young-Kwang , Kim Hwang-Phill , Han Sae-Won , Hur Hyung-Seok , Oh Do Youn , Im Seock-Ah , Bang Yung-Jue , Kim Tae-You
Published: April 2023

Abstract
EGFR tyrosine kinase inhibitors have shown promising efficacy in the treatment of tumors with EGFR mutations and amplifications. However, tyrosine kinase inhibitors have also proven ineffective against most tumors with EGFR wild-type (WT) alleles. Although some genetic changes, including the KRAS mutation, have been shown to confer resistance to tyrosine kinase inhibitors, novel strategies for the treatment of cancer patients with tumors harboring EGFR WT alleles have yet to be thoroughly delineated. The principal objective of this study was to improve our current understanding of drug interactions between EGFR and MAP/ERK kinase (MEK) inhibitors in an effort to gain insight into a novel therapeutic strategy against EGFR WT tumors. Using a panel of human EGFR WT gastric cancer cell lines, we showed that gastric cancer cells harboring the KRAS mutation were selectively sensitive to MEK inhibition as compared with those cells harboring KRAS and PI3K mutations and KRAS WT alleles. However, all cell lines were found to be resistant to EGFR inhibition. The results from Western blots and phosphoprotein arrays showed that, in MEK inhibitor resistant cell lines, AKT was activated through the EGFR/HER3/PI3K pathway following AZD6244 (ARRY-142886) treatment. Blockade of this feedback mechanism through the targeting of MEK and EGFR resulted in detectable synergistic effects in some cell lines in vitro and in vivo. Our results provide the basis for a rational combination strategy against human EGFR WT gastric cancers, predicated on the understanding of cross-talk between the MEK and EGFR pathways. [Mol Cancer Ther 2009;8(9):2526–36]
Data from Expression of a suicidal gene under control of the human secreted protein acidic and rich in cysteine (SPARC) promoter in tumor or stromal cells led to the inhibition of tumor cell growth
Authors: Lopez María V. , Blanco Patricia , Viale Diego L. , Cafferata Eduardo G. , Carbone Cecilia , Gould David , Chernajovsky Yuti , Podhajcer Osvaldo L.
Published: April 2023

Abstract
The successful use of transcriptional targeting for cancer therapy depends on the activity of a given promoter inside the malignant cell. Because solid human tumors evolve as a “cross-talk” between the different cell types within the tumor, we hypothesized that targeting the entire tumor mass might have better therapeutic effect. Secreted protein acidic and rich in cysteine (SPARC) is a matricellular protein overexpressed in different human cancers malignant melanomas both in the malignant cells compartment as in the stromal one (fibroblasts and endothelial cells). We have shown that expression of the herpes simplex virus–thymidine kinase (TK) gene driven by the SPARC promoter in combination with ganciclovir inhibited human melanoma cell growth in monolayer as well as in multicellular spheroids. This inhibitory effect was observed both in homotypic spheroids composed of melanoma cells alone as well as in spheroids made of melanoma cells and stromal cells. Expression of the TK gene was also efficient to inhibit the in vivo tumor growth of established melanomas when TK was expressed either by the malignant cells themselves or by coadministered endothelial cells. Our data suggest that the use of therapeutic genes driven by SPARC promoter could be a valuable strategy for cancer therapy aiming to target all the cellular components of the tumor mass. [Mol Cancer Ther 2006;5(10):2503–11]
Data from From NPC Therapeutic Target Identification to Potential Treatment Strategy
Authors: Lan Ming-Ying , Chen Chi-Long , Lin Kuan-Ting , Lee Sheng-An , Yang Wu-Lung R. , Hsu Chun-Nan , Wu Jaw-Ching , Ho Ching-Yin , Lin Jin-Ching , Huang Chi-Ying F.
Published: April 2023

Abstract
Nasopharyngeal carcinoma (NPC) is relatively rare in Western countries but is a common cancer in southern Asia. Many differentially expressed genes have been linked to NPC; however, how to prioritize therapeutic targets and potential drugs from unsorted gene lists remains largely unknown. We first collected 558 upregulated and 993 downregulated NPC genes from published microarray data and the primary literatures. We then postulated that conversion of gene signatures into the protein-protein interaction network and analyzing the network topologically could provide insight into key regulators involved in tumorigenesis of NPC. Of particular interest was the presence of cliques, called fully connected subgraphs, in the inferred NPC networks. These clique-based hubs, connecting with more than three queries and ranked higher than other nodes in the NPC protein-protein interaction network, were further narrowed down by pathway analysis to retrieve 24 upregulated and 6 downregulated bottleneck genes for predicting NPC carcinogenesis. Moreover, additional oncogenes, tumor suppressor genes, genes involved in protein complexes, and genes obtained after functional profiling were merged with the bottleneck genes to form the final gene signature of 38 upregulated and 10 downregulated genes. We used the initial and final NPC gene signatures to query the Connectivity Map, respectively, and found that target reduction through our pipeline could efficiently uncover potential drugs with cytotoxicity to NPC cancer cells. An integrative Web site (http://140.109.23.188:8080/NPC) was established to facilitate future NPC research. This in silico approach, from target prioritization to potential drugs identification, might be an effective method for various cancer researches. Mol Cancer Ther; 9(9); 2511–23. ©2010 AACR.
Data from Pharmacologic inhibitors of IκB kinase suppress growth and migration of mammary carcinosarcoma cells in vitro and prevent osteolytic bone metastasis in vivo
Authors: Idris Aymen I. , Libouban Hélène , Nyangoga Hervé , Landao-Bassonga Euphemie , Chappard Daniel , Ralston Stuart H.
Published: April 2023

Abstract
The NF-κB signaling pathway is known to play an important role in the regulation of osteoclastic bone resorption and cancer cell growth. Previous studies have shown that genetic inactivation of IκB kinase (IKK), a key component of NF-κB signaling, inhibits osteoclastogenesis, but the effects of pharmacologic IKK inhibitors on osteolytic bone metastasis are unknown. Here, we studied the effects of the IKK inhibitors celastrol, BMS-345541, parthenolide, and wedelolactone on the proliferation and migration of W256 cells in vitro and osteolytic bone destruction in vivo. All compounds tested inhibited the growth and induced apoptosis of W256 cells as evidenced by caspase-3 activation and nuclear morphology. Celastrol, BMS-345541, and parthenolide abolished IL1β and tumor necrosis factor α–induced IκB phosphorylation and prevented nuclear translocation of NF-κB and DNA binding. Celastrol and parthenolide but not BMS-345541 prevented the activation of both IKKα and IKKβ, and celastrol inhibited IKKα/β activation by preventing the phosphorylation of TAK1, a key receptor–associated factor upstream of IKK. Celastrol and parthenolide markedly reduced the mRNA expression of matrix metalloproteinase 9 and urinary plasminogen activator, and inhibited W256 migration. Administration of celastrol or parthenolide at a dose of 1 mg/kg/day suppressed trabecular bone loss and reduced the number and size of osteolytic bone lesions following W256 injection in rats. Histomorphometric analysis showed that both compounds decreased osteoclast number and inhibited bone resorption. In conclusion, pharmacologic inhibitors of IKK are effective in preventing osteolytic bone metastasis in this model and might represent a promising class of agents to the prevention and treatment of metastatic bone disease associated with breast cancer. [Mol Cancer Ther 2009;8(8):2339–47]
Data from Antimitotic effect of the retinoid 4-oxo-fenretinide through inhibition of tubulin polymerization: a novel mechanism of retinoid growth–inhibitory activity
Authors: Appierto Valentina , Tiberio Paola , Cavadini Elena , Casalini Patrizia , Cappelletti Graziella , Formelli Franca
Published: April 2023

Abstract
The retinoid 4-oxo-N-(4-hydroxyphenyl)retinamide (4-oxo-4-HPR), a metabolite of fenretinide (4-HPR) present in plasma of 4-HPR–treated patients, is very effective in inducing growth inhibition and apoptosis in several cancer cell lines. 4-Oxo-4-HPR and 4-HPR have different mechanisms of action because 4-oxo-4-HPR, unlike 4-HPR, causes marked cell accumulation in G2-M phase. Here, we investigated the molecular events involving 4-oxo-4-HPR–induced cell cycle perturbation in ovarian (A2780 and IGROV-1) and breast (T47D, estrogen receptor+ and BT-20, estrogen receptor-) cancer cells. 4-Oxo-4-HPR induced a delay of mitosis (with mitotic index increasing 5- to 6-fold in all cell lines) without progression beyond the anaphase, as shown by cyclin B1 expression. 4-Oxo-4-HPR induced multipolar spindle formation and phosphorylation of BUBR1, resulting in activation of the spindle checkpoint. Multipolar spindles were not due to impairment of pole-focusing process, loss of centrosome integrity, or modulation of the expression levels of molecules associated with spindle aberrations (Kif 1C, Kif 2A, Eg5, Tara, tankyrase-1, centractin, and TOGp). We show here that 4-oxo-4-HPR targets microtubules because, in treated cells, it interfered with the reassembly of cold-depolymerized spindle microtubules and decreased the polymerized tubulin fraction. In cell-free assays, 4-oxo-4-HPR inhibited tubulin polymerization (50% inhibition of microtubule assembly at 5.9 μmol/L), suggesting a direct molecular interaction with tubulin. In conclusion, by showing that 4-oxo-4-HPR causes mitotic arrest through antimicrotubule activities, we delineate a new molecular mechanism for a retinoid. [Mol Cancer Ther 2009;8(12):3360–8]
Data from Sensitivity of Cancer Cells to Plk1 Inhibitor GSK461364A Is Associated with Loss of p53 Function and Chromosome Instability
Authors: Degenhardt Yan , Greshock Joel , Laquerre Sylvie , Gilmartin Aidan G. , Jing Junping , Richter Mark , Zhang Xiping , Bleam Maureen , Halsey Wendy , Hughes Ashley , Moy Christopher , Liu-Sullivan Nancy , Powers Scott , Bachman Kurtis , Jackson Jeffrey , Weber Barbara , Wooster Richard
Published: April 2023

Abstract
Polo-like kinases are a family of serine threonine kinases that are critical regulators of cell cycle progression and DNA damage response. Predictive biomarkers for the Plk1-selective inhibitor GSK461364A were identified by comparing the genomics and genetics of a panel of human cancer cell lines with their response to a drug washout followed by an outgrowth assay. In this assay, cell lines that have lost p53 expression or carry mutations in the TP53 gene tended to be more sensitive to GSK461364A. These more sensitive cell lines also had increased levels of chromosome instability, a characteristic associated with loss of p53 function. Further mechanistic studies showed that p53 wild-type (WT) and not mutant cells can activate a postmitotic tetraploidy checkpoint and arrest at pseudo-G1 state after GSK461364A treatment. RNA silencing of WT p53 increased the antiproliferative activity of GSK461364A. Furthermore, silencing of p53 or p21/CDKN1A weakened the tetraploidy checkpoint in cells that survived mitotic arrest and mitotic slippage. As many cancer therapies tend to be more effective in p53 WT patients, the higher sensitivity of p53-deficient tumors toward GSK461364A could potentially offer an opportunity to treat tumors that are refractory to other chemotherapies as well as early line therapy for these genotypes. Mol Cancer Ther; 9(7); 2079–89. ©2010 AACR.
Data from Phase I Safety, Pharmacokinetic, and Biomarker Study of BIBF 1120, an Oral Triple Tyrosine Kinase Inhibitor in Patients with Advanced Solid Tumors
Authors: Okamoto Isamu , Kaneda Hiroyasu , Satoh Taroh , Okamoto Wataru , Miyazaki Masaki , Morinaga Ryotaro , Ueda Shinya , Terashima Masaaki , Tsuya Asuka , Sarashina Akiko , Konishi Koichi , Arao Tokuzo , Nishio Kazuto , Kaiser Rolf , Nakagawa Kazuhiko
Published: April 2023

Abstract
BIBF 1120 is an oral multitargeted tyrosine kinase inhibitor that blocks the activity of vascular endothelial growth factor (VEGF) and other growth factor receptors. We have done a phase I study to evaluate the safety, pharmacokinetics, and pharmacodynamic biomarkers of BIBF 1120. Patients with advanced refractory solid tumors were treated with BIBF 1120 at oral doses of 150 to 250 mg twice daily. Drug safety and pharmacokinetics were evaluated, as were baseline and post-treatment levels of circulating CD117-positive bone marrow–derived progenitor cells and plasma soluble VEGF receptor 2 as potential biomarkers for BIBF 1120. Twenty-one patients were treated at BIBF 1120 doses of 150 (n = 3), 200 (n = 12), or 250 mg twice daily (n = 6). Dose-limiting toxicities of reversible grade 3 or 4 elevations of liver enzymes occurred in 3 of 12 patients at 200 mg twice daily and 3 of 6 patients at 250 mg twice daily. Stable disease was achieved in 16 (76.2%) patients, and median progression-free survival was 113 days (95% confidence interval, 77-119 d). Pharmacokinetic analysis indicated that the maximum plasma concentration and area under the curve for BIBF 1120 increased with the dose within the dose range tested. Levels of CD117-positive bone marrow–derived progenitors and soluble VEGF receptor 2 decreased significantly during treatment over all BIBF 1120 dose cohorts. In conclusion, the maximum tolerated dose of BIBF 1120 in the current study was determined to be 200 mg twice daily, and our biomarker analysis indicated that this angiokinase inhibitor is biologically active. Mol Cancer Ther; 9(10); 2825–33. ©2010 AACR.
Data from Sorafenib Activates CD95 and Promotes Autophagy and Cell Death via Src Family Kinases in Gastrointestinal Tumor Cells
Authors: Park Margaret A. , Reinehr Roland , Häussinger Dieter , Voelkel-Johnson Christina , Ogretmen Besim , Yacoub Adly , Grant Steven , Dent Paul
Published: April 2023

Abstract
Sorafenib and vorinostat interact in a synergistic fashion to kill carcinoma cells by activating CD95; the present studies have determined how sorafenib and vorinostat individually contribute to CD95 activation. Sorafenib (3–6 μmol/L) promoted a dose-dependent increase in Src Y416, ERBB1 Y845 and CD95 Y232/Y291 phosphorylation, and Src Y527 dephosphorylation. Low levels of sorafenib-induced (3 μmol/L) CD95 tyrosine phosphorylation did not promote surface localization whereas sorafenib (6 μmol/L), or sorafenib (3 μmol/L) and vorinostat (500 nmol/L) treatment promoted higher levels of CD95 phosphorylation which correlated with DISC formation, receptor surface localization, and autophagy. CD95 (Y232F, Y291F) was not tyrosine phosphorylated and was unable to localize plasma membrane or induce autophagy. Knockdown/knockout of Src family kinases abolished sorafenib-induced CD95 tyrosine phosphorylation, DISC formation, and the induction of cell death and autophagy. Knockdown of platelet-ived growth factor receptor-β enhanced Src Y416 and CD95 tyrosine phosphorylation, which correlated with elevated CD95 plasma membrane levels and autophagy, and with a reduced ability of sorafenib to promote CD95 membrane localization. Vorinostat increased reactive oxygen species levels, and in a delayed NFκB-dependent fashion, those of FAS ligand and CD95. Neutralization of FAS-L did not alter the initial rapid drug-induced activation of CD95; however, neutralization of FAS-L reduced sorafenib + vorinostat toxicity by ∼50%. Thus, sorafenib contributes to CD95 activation by promoting receptor tyrosine phosphorylation, whereas vorinostat contributes to CD95 activation via the initial facilitation of reactive oxygen species generation and subsequently of FAS-L expression. Mol Cancer Ther; 9(8); 2220–31. ©2010 AACR.
Data from Imatinib blocks migration and invasion of medulloblastoma cells by concurrently inhibiting activation of platelet-derived growth factor receptor and transactivation of epidermal growth factor receptor
Authors: Abouantoun Thamara J. , MacDonald Tobey J.
Published: April 2023

Abstract
Platelet-derived growth factor (PDGF) receptor (PDGFR) expression correlates with metastatic medulloblastoma. PDGF stimulation of medulloblastoma cells phosphorylates extracellular signal-regulated kinase (ERK) and promotes migration. We sought to determine whether blocking PDGFR activity effectively inhibits signaling required for medulloblastoma cell migration and invasion. DAOY and D556 human medulloblastoma cells were treated with imatinib mesylate (Gleevec), a PDGFR tyrosine kinase inhibitor, or transfected with small interfering RNA (siRNA) to PDGFRB to test the effects of blocking PDGFR phosphorylation and expression, respectively. PDGFR cell signaling, migration, invasion, survival, and proliferation following PDGF-BB stimulation, with and without PDGFR inhibition, were measured. PDGF-BB treatment of cells increased PDGFRB, Akt and ERK phosphorylation, and transactivated epidermal growth factor receptor (EGFR), which correlated with enhanced migration, survival, and proliferation. Imatinib (1 μmol/L) treatment of DAOY and D556 cells inhibited PDGF-BB- and serum-mediated migration and invasion at 24 and 48 h, respectively, and concomitantly inhibited PDGF-BB activation of PDGFRB, Akt, and ERK but increased PTEN expression and activity. Imatinib treatment also induced DAOY cell apoptosis at 72 h and inhibited DAOY and D556 cell proliferation at 48 h. siRNA silencing of PDGFRB similarly inhibited signaling, migration, and survival and both siRNA and imatinib treatment inhibited PDGF-BB-mediated EGFR transactivation, indicating that the effects of imatinib treatment are specific to PDGFRB target inhibition. These results indicate that PDGFRB tyrosine kinase activity is critical for migration and invasion of medulloblastoma cells possibly by transactivating EGFR; thus, imatinib may represent an important novel therapeutic agent for the treatment of medulloblastoma. [Mol Cancer Ther 2009;8(5):1137–47]
Data from The FLT3 Internal Tandem Duplication Mutation Is a Secondary Target of the Aurora B Kinase Inhibitor AZD1152-HQPA in Acute Myelogenous Leukemia Cells
Authors: Grundy Martin , Seedhouse Claire , Shang Shilli , Richardson Jaineeta , Russell Nigel , Pallis Monica
Published: April 2023

Abstract
Aurora kinases play an essential role in orchestrating chromosome alignment, segregation, and cytokinesis during mitotic progression and both aurora-A and B are frequently overexpressed in a variety of human malignancies. In this study, we report the effects of AZD1152-HQPA, a highly selective inhibitor of aurora-B kinase, in acute myeloid leukemia (AML) cell lines and primary samples. We show that AZD1152-HQPA inhibits the phosphorylation of Histone H3 (pHH3) on serine 10 resulting in polyploid cells, apoptosis, and loss of viability in a panel of AML cell lines. We also show that AZD1152-HQPA sensitivity in our cell lines is irrespective of p53 status and the FLT3-ITD–expressing MOLM-13 and MV4-11 cell lines are particularly sensitive to AZD1152-HQPA. Internal tandem duplications (ITD) within the FLT3 tyrosine kinase receptor are found in ∼25% of AML patients and are associated with a poor prognosis. Here, we report that AZD1152-HQPA directly targets phosphorylated FLT3 along with inhibiting its downstream target phospho–signal transducer and activator of transcription 5 (STAT5) in the FLT3-ITD cell lines. We show pHH3 expression in primary AML blasts and its inhibition by AZD1152-HQPA at low doses in all of our primary samples tested. AZD1152-HQPA inhibits the clonogenic potential of primary AML samples, with FLT3-ITD samples being the most sensitive (P = 0.029). FLT3-ITD primary samples are also more sensitive to pHH3 inhibition (P = 0.022) and are particularly sensitive to pSTAT5 downregulation after treatment with AZD1152-HQPA compared with FLT3 wild-type samples (P = 0.007). We conclude that mutant FLT3 is a secondary target of AZD1152-HQPA and that FLT3-ITD primary samples are particularly sensitive to the drug. Mol Cancer Ther; 9(3); 661–72
Data from Dehydrocostuslactone disrupts signal transducers and activators of transcription 3 through up-regulation of suppressor of cytokine signaling in breast cancer cells
Authors: Kuo Po-Lin , Ni Wen-Chiu , Tsai Eing-Mei , Hsu Ya-Ling
Published: April 2023

Abstract
This study investigates the anticancer effect of dehydrocostuslactone (DHE), a plant-derived sesquiterpene lactone, on human breast cancer cells. DHE inhibits cell proliferation by inducing cells to undergo cell cycle arrest and apoptosis. DHE suppresses the expression of cyclin D, cyclin A, cyclin-dependent kinase 2, and cdc25A and increases the amount of p53 and p21, resulting in G0/G1-S phase arrest in MCF-7 cells. In contrast, DHE caused S-G2/M arrest by increasing p21 expression and chk1 activation and inhibiting cyclin A, cyclin B, cdc25A, and cdc25C expression in MDA-MB-231 cells. DHE induces up-regulation of Bax and Bad, down-regulation of Bcl-2 and Bcl-XL, and nuclear relocation of the mitochondrial factors apoptosis-inducing factor and endonuclease G. We also found that DHE inhibits survival signaling through the Janus tyrosine kinase-signal transducer and activator of transcription-3 signaling by increasing the expression of suppressors of cytokine signaling (SOCS)-1 and SOCS-3. Reduction of SOCS-1 and SOCS-3 expression by small interfering RNA inhibits DHE-mediated signal transducer and activator of transcription-3 inhibition, p21 up-regulation, and cyclin-dependent kinase 2 blockade, supporting the hypothesis that DHE inhibits cell cycle progression and cell death through SOCS-1 and SOCS-3. Significantly, animal studies have revealed a 50% reduction in tumor volume after a 45-day treatment period. Taken together, this study provides new insights into the molecular mechanism of the DHE action that may contribute to the chemoprevention of breast cancer. [Mol Cancer Ther 2009;8(5):1328–39]
Data from Keratin down-regulation in vimentin-positive cancer cells is reversible by vimentin RNA interference, which inhibits growth and motility
Authors: Paccione Rachel J. , Miyazaki Hiroshi , Patel Vyomesh , Waseem Ahmad , Gutkind J. Silvio , Zehner Zendra E. , Yeudall W. Andrew
Published: April 2023

Abstract
At later stages of tumor progression, epithelial carcinogenesis is associated with transition to a mesenchymal phenotype, which may contribute to the more aggressive properties of cancer cells and may be stimulated by growth factors such as epidermal growth factor and transforming growth factor-β. Previously, we found that cells derived from a nodal metastatic squamous cell carcinoma are highly proliferative and motile in vitro and tumorigenic in vivo. In the current study, we have investigated the role of vimentin in proliferation and motility. Cells derived from nodal metastasis express high levels of vimentin, which is undetectable in tumor cells derived from a synchronous primary lesion of tongue. Vimentin expression was enhanced by epidermal growth factor and transforming growth factor-β both independently and in combination. Use of RNA interference resulted in the generation of stable cell lines that express constitutively low levels of vimentin. RNA interference-mediated vimentin knockdown reduced cellular proliferation, migration, and invasion through a basement membrane substitute by 3-fold compared with nontargeting controls. In addition, cells with reduced vimentin reexpressed differentiation-specific keratins K13, K14, and K15 as a result of increased gene transcription as judged by quantitative PCR and promoter-reporter assays. Furthermore, cells in which vimentin expression was reduced showed a greatly decreased tumorigenic potential, as tumors developing from these cells were 70% smaller than those from control cells. The data suggest that reversal of the mesenchymal phenotype by inhibiting vimentin expression results in reexpression of epithelial characteristics and reduced tumor aggressiveness. [Mol Cancer Ther 2008;7(9):2894–903]
Data from Inhibition of type I histone deacetylase increases resistance of checkpoint-deficient cells to genotoxic agents through mitotic delay
Authors: Alao John P. , Olesch Jeanette , Sunnerhagen Per
Published: April 2023

Abstract
Histone deacetylase (HDAC) inhibitors potently inhibit tumor growth and are currently being evaluated for their efficacy as chemosensitizers and radiosensitizers. This efficacy is likely to be limited by the fact that HDAC inhibitors also induce cell cycle arrest. Deletion of the class I HDAC Rpd3 has been shown to specifically suppress the sensitivity of Saccharomyces cerevisiae DNA damage checkpoint mutants to UV and hydroxyurea. We show that in the fission yeast Schizosaccharomyces pombe, inhibition of the homologous class I HDAC specifically suppresses the DNA damage sensitivity of checkpoint mutants. Importantly, the prototype HDAC inhibitor Trichostatin A also suppressed the sensitivity of DNA damage checkpoint but not of DNA repair mutants to UV and HU. TSA suppressed DNA damage activity independently of the mitogen-activated protein kinase–dependent and spindle checkpoint pathways. We show that TSA delays progression into mitosis and propose that this is the main mechanism for suppression of the DNA damage sensitivity of S. pombe checkpoint mutants, partially compensating for the loss of the G2 checkpoint pathway. Our studies also show that the ability of HDAC inhibitors to suppress DNA damage sensitivity is not species specific. Class I HDACs are the major target of HDAC inhibitors and cancer cells are often defective in checkpoint activation. Effective use of these agents as chemosensitizers and radiosensitizers may require specific treatment schedules that circumvent their inhibition of cell cycle progression. [Mol Cancer Ther 2009;8(9):2606–15]
Data from Mapatumumab and lexatumumab induce apoptosis in TRAIL-R1 and TRAIL-R2 antibody-resistant NSCLC cell lines when treated in combination with bortezomib
Authors: Luster Troy A. , Carrell Jeffrey A. , McCormick Kathy , Sun David , Humphreys Robin
Published: April 2023

Abstract
Mapatumumab and lexatumumab are fully human monoclonal antibodies that bind and activate human tumor necrosis factor-related apoptosis-inducing ligand receptors 1 and 2, respectively. These antibodies induce apoptosis in various tumor cell types, although the degree of sensitivity can vary from highly sensitive to completely resistant. Importantly, tumor cells that are partially or completely resistant to mapatumumab or lexatumumab can often be sensitized when treated in combination with chemotherapeutic drugs. In this regard, the proteasome inhibitor bortezomib has recently shown synergistic activity against established lymphoma cell lines and primary lymphomas when combined with mapatumumab and lexatumumab. Here, we report similar findings using a panel of human non-small cell lung cancer (NSCLC) cell lines. Specifically, we show that bortezomib rapidly induces sensitivity to mapatumumab and lexatumumab in NSCLC cell lines that are completely resistant to antibody alone and that bortezomib concentrations as low as 25 nmol/L sensitize NSCLC cells to the antibodies. Furthermore, bortezomib at the tested concentration has minimal effect on its own, indicating the combination generates synergistic cytotoxicity. Combination treatment induces activation of the caspase cascade and the effect of the combination is caspase dependent. Bortezomib treatment increases the intracellular levels of several important apoptosis regulators that may mediate enhanced sensitivity to mapatumumab and lexatumumab. These results suggest future evaluation of mapatumumab or lexatumumab in combination with bortezomib is warranted in NSCLC patients. [Mol Cancer Ther 2009;8(2):292–302]
Data from miR-192/miR-215 Influence 5-Fluorouracil Resistance through Cell Cycle-Mediated Mechanisms Complementary to Its Post-transcriptional Thymidilate Synthase Regulation
Authors: Boni Valentina , Bitarte Nerea , Cristobal Ion , Zarate Ruth , Rodriguez Javier , Maiello Evaristo , Garcia-Foncillas Jesus , Bandres Eva
Published: April 2023

Abstract
Thymidylate synthase (TYMS) is a target of the most widely used chemotherapeutic agents against gastrointestinal malignancies, the fluoropyrimidine-based therapy. TYMS expression levels have been identified as predictive biomarkers for 5-fluoruracil (FU) response in colorectal cancer, but their clinical utility remains controversial. The complexity of fluoropyrimidine response must require more mechanisms that currently have not been completely elucidated. In this context, microRNAs (miRNA) may play a role in modulating chemosensitivity. By carrying out an in silico analysis coupled to experimental validation, we detected that miR-192 and miR-215 target TYMS expression in colorectal cancer cell lines. However, downregulation of TYMS by these miRNAs does not sensitize colorectal cancer cell lines to FU treatment. The overexpression of miR-192/215 significantly reduces cell proliferation by targeting cell cycle progression. This effect was partially associated with p53 status, because reduction of cell proliferation and cell cycle arrest was associated with p21 and p27 induction. The decrease of S-phase cells by these miRNAs mitigates the effects of S phase–specific drugs and suggests that other mechanisms different from TYMS overexpression are essential to direct FU resistance. Finally, ectopic expression of miR-192/215 might have stronger impact to predict FU response than TYMS inhibition. Prospective studies to elucidate the role of these miRNAs as predictive biomarkers to FU are necessary. Mol Cancer Ther; 9(8); 2265–75. ©2010 AACR.
Data from Sorafenib, a Multikinase Inhibitor, Enhances the Response of Melanoma to Regional Chemotherapy
Authors: Augustine Christina K. , Toshimitsu Hiroaki , Jung Sin-Ho , Zipfel Patricia A. , Yoo Jin S. , Yoshimoto Yasunori , Selim M. Angelica , Burchette James , Beasley Georgia M. , McMahon Nicole , Padussis James , Pruitt Scott K. , Ali-Osman Francis , Tyler Douglas S.
Published: April 2023

Abstract
Melanoma responds poorly to standard chemotherapy due to its intrinsic chemoresistance. Multiple genetic and molecular defects, including an activating mutation in the BRaf kinase gene, are associated with melanoma, and the resulting alterations in signal transduction pathways regulating proliferation and apoptosis are thought to contribute to its chemoresistance. Sorafenib, a multikinase inhibitor that targets BRaf kinase, is Food and Drug Administration approved for use in advanced renal cell and hepatocellular carcinomas. Although sorafenib has shown little promise as a single agent in melanoma patients, recent clinical trials suggest that, when combined with chemotherapy, it may have more benefit. We evaluated the ability of sorafenib to augment the cytotoxic effects of melphalan, a regional chemotherapeutic agent, and temozolomide, used in systemic and regional treatment of melanoma, on a panel of 24 human melanoma-derived cell lines and in an animal model of melanoma. Marked differences in response to 10 μmol/L sorafenib alone were observed in vitro across cell lines. Response to sorafenib significantly correlated with extracellular signal-regulated kinase (ERK) downregulation and loss of Mcl-1 expression (P < 0.05). Experiments with the mitogen-activated protein kinase/ERK kinase inhibitor U0126 suggest a unique role for ERK downregulation in the observed effects. Sorafenib in combination with melphalan or temozolomide led to significantly improved responses in vitro (P < 0.05). In the animal model of melanoma, sorafenib in combination with regional melphalan or regional temozolomide was more effective than either treatment alone in slowing tumor growth. These results show that sorafenib in combination with chemotherapy provides a novel approach to enhance chemotherapeutic efficacy in the regional treatment of in-transit melanoma. Mol Cancer Ther; 9(7); 2090–101. ©2010 AACR.
Data from Increased AKT S473 phosphorylation after mTORC1 inhibition is rictor dependent and does not predict tumor cell response to PI3K/mTOR inhibition
Authors: Breuleux Madlaina , Klopfenstein Matthieu , Stephan Christine , Doughty Cheryl A. , Barys Louise , Maira Saveur-Michel , Kwiatkowski David , Lane Heidi A.
Published: April 2023

Abstract
Mammalian target of rapamycin (mTOR) regulates cellular processes important for progression of human cancer. RAD001 (everolimus), an mTORC1 (mTOR/raptor) inhibitor, has broad antitumor activity in preclinical models and cancer patients. Although most tumor lines are RAD001 sensitive, some are not. Selective mTORC1 inhibition can elicit increased AKT S473 phosphorylation, involving insulin receptor substrate 1, which is suggested to potentially attenuate effects on tumor cell proliferation and viability. Rictor may also play a role because rictor kinase complexes (including mTOR/rictor) regulate AKT S473 phosphorylation. The role of raptor and rictor in the in vitro response of human cancer cells to RAD001 was investigated. Using a large panel of cell lines representing different tumor histotypes, the basal phosphorylation of AKT S473 and some AKT substrates was found to correlate with the antiproliferative response to RAD001. In contrast, increased AKT S473 phosphorylation induced by RAD001 did not correlate. Similar increases in AKT phosphorylation occurred following raptor depletion using siRNA. Strikingly, rictor down-regulation attenuated AKT S473 phosphorylation induced by mTORC1 inhibition. Further analyses showed no relationship between modulation of AKT phosphorylation on S473 and T308 and AKT substrate phosphorylation patterns. Using a dual pan-class I phosphatidylinositol 3-kinase/mTOR catalytic inhibitor (NVP-BEZ235), currently in phase I trials, concomitant targeting of these kinases inhibited AKT S473 phosphorylation, eliciting more profound cellular responses than mTORC1 inhibition alone. However, reduced cell viability could not be predicted from biochemical or cellular responses to mTORC1 inhibitors. These data could have implications for the clinical application of phosphatidylinositol 3-kinase/mTOR inhibitors. [Mol Cancer Ther 2009;8(4):742–53]
Data from Doxorubicin Resistance in a Novel In vitro Model of Human Pleomorphic Liposarcoma Associated with Alternative Lengthening of Telomeres
Authors: Mitchell Marcy A. , Johnson Jay E. , Pascarelli Kara , Beeharry Neil , Chiourea Maria , Gagos Sarantis , Lev Dina , von Mehren Margaret , Kipling David , Broccoli Dominique
Published: April 2023

Abstract
Soft tissue sarcomas are a diverse set of fatal human tumors where few agents have demonstrable clinical efficacy, with the standard therapeutic combination of doxorubicin and ifosfamide showing only a 25% to 30% response rate in large multi-institutional trials. Although liposarcomas are the most common histologic form of adult soft tissue sarcomas, research in this area is severely hampered by the lack of experimentally tractable in vitro model systems. To this end, here we describe a novel in vitro model for human pleomorphic liposarcoma. The cell line (LS2) is derived from a pleomorphic liposarcoma that uses the alternative lengthening of telomeres (ALT) mechanism of telomere maintenance, which may be important in modulating the response of this tumor type to DNA-damaging agents. We present detailed baseline molecular and genomic data, including genome-wide copy number and transcriptome profiles, for this model compared with its parental tumor and a panel of liposarcomas covering multiple histologies. The model has retained essentially all of the detectable alterations in copy number that are seen in the parental tumor, and shows molecular karyotypic and expression profiles consistent with pleomorphic liposarcomas. We also show the utility of this model, together with two additional human liposarcoma cell lines, to investigate the relationship between topoisomerase 2A expression and the sensitivity of ALT-positive liposarcomas to doxorubicin. This model, together with its associated baseline data, provides a powerful new tool to develop treatments for this clinically poorly tractable tumor and to investigate the contribution that ALT makes to modulating sensitivity to doxorubicin. Mol Cancer Ther; 9(3); 682–92
Data from Dual silencing of insulin-like growth factor-I receptor and epidermal growth factor receptor in colorectal cancer cells is associated with decreased proliferation and enhanced apoptosis
Authors: Kaulfuβ Silke , Burfeind Peter , Gaedcke Jochen , Scharf Jens-Gerd
Published: April 2023

Abstract
Overexpression and activation of tyrosine kinase receptors are common features of colorectal cancer. Using the human colorectal cancer cell lines DLD-1 and Caco-2, we evaluated the role of the insulin-like growth factor-I (IGF-I) receptor (IGF-IR) and epidermal growth factor receptor (EGFR) in cellular functions of these cells. We used the small interfering RNA (siRNA) technology to specifically down-regulate IGF-IR and EGFR expression. Knockdown of IGF-IR and EGFR resulted in inhibition of cell proliferation of DLD-1 and Caco-2 cells. An increased rate of apoptosis was associated with siRNA-mediated silencing of IGF-IR and EGFR as assessed by activation of caspase-3/caspase-7. The combined knockdown of both EGFR and IGF-IR decreased cell proliferation and induced cell apoptosis more effectively than did silencing of either receptor alone. Comparable effects on cell proliferation and apoptosis were observed after single and combinational treatment of cells by the IGF-IR tyrosine kinase inhibitor NVP-AEW541 and/or the EGFR tyrosine kinase inhibitor erlotinib. Combined IGF-IR and EGFR silencing by either siRNAs or tyrosine kinase inhibitors diminished the phosphorylation of downstream signaling pathways AKT and extracellular signal–regulated kinase (ERK)-1/2 more effectively than did the single receptor knockdown. Single IGF-IR knockdown inhibited IGF-I–dependent phosphorylation of AKT but had no effect on IGF-I– or EGF-dependent phosphorylation of ERK1/2, indicating a role of EGFR in ligand-dependent ERK1/2 phosphorylation. The present data show that inhibition of the IGF-IR transduction cascade augments the antipoliferative and proapoptotic effects of EGFR inhibition in colorectal cancer cells. A clinical application of combination therapy targeting both EGFR and IGF-IR could be a promising therapeutic strategy.[Mol Cancer Ther 2009;8(4):821–33]
Data from Profiling SLCO and SLC22 genes in the NCI-60 cancer cell lines to identify drug uptake transporters
Authors: Okabe Mitsunori , Szakács Gergely , Reimers Mark A. , Suzuki Toshihiro , Hall Matthew D. , Abe Takaaki , Weinstein John N. , Gottesman Michael M.
Published: April 2023

Abstract
Molecular and pharmacologic profiling of the NCI-60 cell panel offers the possibility of identifying pathways involved in drug resistance or sensitivity. Of these, decreased uptake of anticancer drugs mediated by efflux transporters represents one of the best studied mechanisms. Previous studies have also shown that uptake transporters can influence cytotoxicity by altering the cellular uptake of anticancer drugs. Using quantitative real-time PCR, we measured the mRNA expression of two solute carrier (SLC) families, the organic cation/zwitterion transporters (SLC22 family) and the organic anion transporters (SLCO family), totaling 23 genes in normal tissues and the NCI-60 cell panel. By correlating the mRNA expression pattern of the SLCO and SLC22 family member gene products with the growth-inhibitory profiles of 1,429 anticancer drugs and drug candidate compounds tested on the NCI-60 cell lines, we identified SLC proteins that are likely to play a dominant role in drug sensitivity. To substantiate some of the SLC-drug pairs for which the SLC member was predicted to be sensitizing, follow-up experiments were performed using engineered and characterized cell lines overexpressing SLC22A4 (OCTN1). As predicted by the statistical correlations, expression of SLC22A4 resulted in increased cellular uptake and heightened sensitivity to mitoxantrone and doxorubicin. Our results indicate that the gene expression database can be used to identify SLCO and SLC22 family members that confer sensitivity to cancer cells. [Mol Cancer Ther 2008;7(9):3081–91]
Data from The role of vascular endothelial growth factor SNPs as predictive and prognostic markers for major solid tumors
Authors: Jain Lokesh , Vargo Craig A. , Danesi Romano , Sissung Tristan M. , Price Douglas K. , Venzon David , Venitz Jürgen , Figg William D.
Published: April 2023

Abstract
Angiogenesis is crucial for development and metastasis of tumors, and vascular endothelial growth factor (VEGF) is a key mediator of this process. The importance of VEGF in tumorigenesis and tumor progression makes it an attractive target for the development of anticancer therapies. Inhibition of angiogenesis has shown promising clinical efficacy; however, not all patients treated with antiangiogenic agents derive benefit from them. Some patients are predisposed to refractory disease, whereas others develop resistance after initial response. Patients may also have different severity of drug-related adverse events. Optimization of drug administration based on disease status and individual responsiveness is important in limiting the treatment failure and minimization of side-effects. Single nucleotide polymorphisms (SNP) in VEGF may alter VEGF protein concentrations, influence the process of angiogenesis, and may relate to interindividual variation in the risk and progression of selected tumors, and their resistance to treatments. This review examines the role of SNPs in the VEGF gene as predictive and prognostic markers for major solid tumors, including the breast, non-small cell lung, colorectal, and prostate cancers. Selected VEGF SNPs seem to be associated with risk of these cancers; however, there is lack of unanimity in findings, in part influenced by differences in study design and analysis. [Mol Cancer Ther 2009;8(9):2496–508]
Data from Efficacy and pharmacodynamic effects of bosutinib (SKI-606), a Src/Abl inhibitor, in freshly generated human pancreas cancer xenografts
Authors: Messersmith Wells A. , Rajeshkumar N.V. , Tan Aik Choon , Wang Xiao Fei , Diesl Veronica , Choe Sung E. , Follettie Max , Coughlin Christina , Boschelli Frank , Garcia-Garcia Elena , Lopez-Rios Fernando , Jimeno Antonio , Hidalgo Manuel
Published: April 2023

Abstract
Recently, Src tyrosine kinase has emerged as an attractive target for anticancer therapy, and Src is overexpressed in pancreatic cancer. The purpose of the study was to investigate the in vivo efficacy and pharmacodynamic effects of bosutinib (SKI-606), a Src/Abl inhibitor, using a panel of human pancreatic tumor xenografts. Surgically resected human pancreatic tumors were implanted into female nude mice and randomized to bosutinib versus control. Src and other pathways were analyzed by Western Blot, IHC, and Affymetrix U133 Plus 2.0 gene arrays. Of 15 patient tumors, 3 patient tumors were found to be sensitive to bosutinib, defined as tumor growth of <45% than that of control tumors. There were no definite differences between sensitive and resistant tumors in the baseline Src kinase pathway protein expression assessed by Western Blot. Caveolin-1 expression, as assessed by reverse transcription-PCR and immunohistochemistry, was frequently higher in sensitive cases. In sensitive tumors, bosutinib resulted in increased apoptosis. Phosphorylation of key signaling molecules downstream of Src, signal transducers and activators of transcription 3, and signal transducers and activators of transcription 3, were significantly inhibited by bosutinib. K-Top Scoring Pairs analysis of gene arrays gave a six-gene classifier that predicted resistance versus sensitivity in six validation cases. These results may aid the clinical development of bosutinib and other Src inhibitors in pancreas cancer. [Mol Cancer Ther 2009;8(6):1484–93]
Data from Trabectedin (ET-743) promotes differentiation in myxoid liposarcoma tumors
Authors: Forni Claudia , Minuzzo Mario , Virdis Emanuela , Tamborini Elena , Simone Matteo , Tavecchio Michele , Erba Eugenio , Grosso Federica , Gronchi Alessandro , Aman Pierre , Casali Paolo , D'Incalci Maurizio , Pilotti Silvana , Mantovani Roberto
Published: April 2023

Abstract
Differentiation is a complex set of events that can be blocked by rearrangements of regulatory genes producing fusion proteins with altered properties. In the case of myxoid liposarcoma (MLS) tumors, the causative abnormality is a fusion between the CHOP transcription factor and the FUS or EWS genes. CHOP belongs to and is a negative regulator of the large CAAT/enhancer binding protein family whose α, β,and δ members are master genes of adipogenesis. Recent clinical data indicate a peculiar sensitivity of these tumors to the natural marine compound trabectedin. One hypothesis is that the activity of trabectedin is related to the inactivation of the FUS-CHOP oncogene. We find that trabectedin causes detachment of the FUS-CHOP chimera from targeted promoters. Reverse transcription-PCR and chromatin immunoprecipitation analysis in a MLS line and surgical specimens of MLS patients in vivo show activation of the CAAT/enhancer binding protein–mediated transcriptional program that leads to morphologic changes of terminal adipogenesis. The activity is observed in cells with type 1 but not type 8 fusions. Hence, the drug induces maturation of MLS lipoblasts in vivo by targeting the FUS-CHOP–mediated transcriptional block. These data provide a rationale for the specific activity of trabectedin and open the perspective of combinatorial treatments with drugs acting on lipogenic pathways. [Mol Cancer Ther 2009;8(2):449–57]
Data from Influence of small interfering RNA corresponding to ets homologous factor on senescence-associated modulation of prostate carcinogenesis
Authors: Park Chaehwa , Lee Inkyoung , Kang Won Ki
Published: April 2023

Abstract
Senescence is thought to be an inherent tumor-suppressive mechanism. In the process of identifying senescence-associated genes, we found significant suppression of the ets homologous factor (EHF) in cancer cells in a state of DNA damage–induced senescence. In this study, we show that EHF provides substantial drug resistance in PC-3 prostate cancer cells by inhibiting senescence and cell cycle arrest. Knockdown of EHF by small interfering RNA inhibited cell proliferation and induced a premature cellular senescence characterized by hypophosphorylation of Rb and increased level of p27, with concomitant decreases of cyclin A, cdc2, and E2F1. Telomeric repeat amplification protocol analysis showed that transient EHF knockdown significantly decreased telomerase activity, whereas this activity was increased by overexpression of EHF. In vivo tumorigenesis analyses revealed that tumors derived from EHF knockdown cells were significantly smaller than those derived from control cells (P < 0.0001). Further, the preestablished tumors were reduced after the injection of small interfering RNA corresponding to EHF (P = 0.0122). Collectively, these observations indicate that aberrant expression of EHF and the subsequent disruption of p27-mediated senescence and telomerase activity is likely to contribute significantly to tumor progression, and furthermore that EHF might be a promising target for future cancer therapeutics. [Mol Cancer Ther 2006;5(12):3191–6]