bluuebunny/crossref_metadata_2025_split huggingface dataset:
Abstract B85: Structure and function of a novel Bag1-L derived peptide that inhibits prostate tumor cell growth
Authors: Neeb Antje , Maddalo Danilo , Muhle Claudia , Jehle Katja , Wenzel Wolfgang , Cato Andrew CB 
Published: June 2012

Abstract
Peptide ligands that specifically target tumor cells represent useful tools for cancer therapy. They can be used for the transport and specific delivery of cell death-inducing sequences or chemotoxic drugs to tumor cells. Here we describe a peptide from a conserved region of Bag-1 (Bcl-2 associated athanogene-1) proteins that induces cell death without the need for a pro-drug conjugate or fusion with a death-inducing sequence. Stable expression of the Bag-1 peptide in 22Rv.1 prostate tumor cells interferes with tumor cell growth and survival in vivo and in vitro and elevates the level of apoptosis in tumor cells treated with the topoisomerase inhibitor II etoposide. Structural analysis using NMR and circular dichronism (CD) show that this peptide is completely unstructured. Nevertheless it interacts with specific sequences of the glucose regulated proteins GRP75 and GRP78. Domain mapping studies identified the ATPase domain of GRP78 and the substrate-binding domain of GRP75 as interaction sites of the Bag1-peptide. Both GRP75 and GRP78 belong to the heat shock protein family and act as protective chaperones in the unfolded protein response. In addition both proteins are over expressed in many human tumors and are found exclusively on the surface of tumor cells. In particular, the GRP78 protein that is present on the surface of tumor cells is glycosylated. Using deglycosylation and GST-pull down analysis, we can show that the Bag1-peptide also binds to the glycosylated form of GRP78 indicating its ability to target tumor cells by binding to the cell surface. Thus we have identified a candidate peptide for a broad-based tumor therapy that function by interfering with the action of GRP75 and GRP78.
Citation Information: Mol Cancer Ther 2009;8(12 Suppl):B85.
Abstract B90: Understanding the effects of RAF inhibitors on RAF signaling in B-RAF V600E mutant versus wild type tumors
Authors: Yen Ivana , Song Kyung , Stokoe David , Brandhuber Barbara , Gloor Susan , Aliagas Ignacio , Anderson Daniel , Morales Tony , Vigers Guy , Ludlam Mary , Alvarado Ryan , Liu Bonnie , Sideris Steve , Ramaswamy Sreema , Heise Christopher , Belvin Marcia , Friedman Lori , Hatzivassiliou Georgia , Malek Shiva 
Published: June 2012

Abstract
Constitutive activation of the Ras, RAF, mitogen-activated protein kinase (MEK), and extracellular signal regulated kinase (ERK) pathway is a common finding in many human cancers. Activating mutations in K-Ras or B-RAF constitute over 30% of all mutations in human tumors. Therefore, identifying therapeutic strategies to downregulate this pathway could have broad therapeutic impact. It has been demonstrated that RAF inhibitors selectively inhibit B-RAFV600E tumors and not Ras mutant tumors, despite functioning as one of the key effector enzymes downstream of Ras and upstream of MEK. In this work we demonstrate that although RAF inhibitors effectively inhibit phospho-MEK and phospho-ERK levels in B-RAFV600E cells, pathway induction is observed for RAF inhibitors in B-RAF WT/K-Ras Mutant or B-RAF WT/K-Ras WT cell lines as evidenced by increases in phospho-MEK, phospho-ERK and phospho-p90RSK levels. We also show that with increasing concentrations of RAF inhibitors, the downstream pathway can be inhibited in WT B-RAF and mutant K-Ras cell lines. Stimulation of the pathway with growth factors or serum can attenuate phospho-MEK and phospho-ERK induction upon treatment with RAF inhibitors. Additionally, mechanistic studies demonstrate that RAF inhibitors can directly activate RAF kinase activity. Taken together, our data suggests that RAF inhibitors may have opposing functions as both activators and inhibitors of the MAPK pathway, depending on cellular context. These results provide new insight into the therapeutic utility of MAPK pathway inhibitors, and emphasize the importance of correlating target occupancy with pharmacodynamic markers of efficacy, and of targeting defined genetic backgrounds in cancer treatment.
Citation Information: Mol Cancer Ther 2009;8(12 Suppl):B90.
Abstract B91: RNAi knockdown of Mek2, but not Mek1, increases proliferation of malignant and non-malignant human breast cells
Authors: Jeffress Mara , Beliveau Alain , Campeau Eric , Gray Joe , Yaswen Paul 
Published: June 2012

Abstract
We are using shRNAs against Mek1 and/or Mek2 to determine the individual contributions of Mek1 and Mek2 to proliferation, migration and Mek inhibitor sensitivity in malignant and non-malignant human breast epithelial cell lines. We found in both malignant (MCF7 and MDAMB231) and non-malignant immortalized (184vTERT and MCF10A) breast cell lines that, despite significant shRNA-mediated reductions (&gt;95%) in the expression of Mek1, Mek2, or both kinases, the cells maintained long-term growth. In fact, the shMek2 lines grew significantly faster and were more motile than controls, suggesting that in some breast cancers, drugs that specifically target Mek1 might be more effective than those which target both Mek1 and 2.
In MCF7 cells, levels of phosphorylated (P)-Erk1 and 2 were significantly decreased or undetectable in the presence of Mek shRNAs, indicating that Erk phosphorylation may be dispensable for cell proliferation in these cells. In contrast, in 184vTERT and MCF10A, phosphorylated Erk levels remained constant despite the knockdown of both Mek1 and Mek2. This latter result indicated that, in some breast cells, another kinase is likely to phosphorylate Erk1/2 in the absence of Mek1 and Mek2. The Mek5 kinase is genetically most similar to Mek1 and Mek2, making it an attractive candidate for further investigation. Mek5 is expressed in 184vTERT, and its total protein levels are not altered when Mek1 and 2 are knocked down. A preliminary experiment indicates that siRNA induced knockdown of Mek5 expression leads to decreased ERK1/2 phosphorylation in 184v-TERT cells independently of Mek1/2 expression. We are currently investigating whether this occurs in other breast cell lines.
Collectively, our data indicate that in at least some breast cells, both Mek1 and Mek2 are dispensable for proliferation and survival, and that parallel pathways are sufficient for relaying signals from cell surface receptors, independently of Mek1/2 and/or P-Erk1/2. This data may explain why Mek inhibitors, which target both Mek1 and Mek2, have not done well clinically.
Citation Information: Mol Cancer Ther 2009;8(12 Suppl):B91.
Abstract B97: Dichloroacetate (DCA) enhances activities of sorafenib against hepatocellular carcinoma (HCC) via modulation of aberrant cellular metabolism of HCC cells
Authors: Shen Ying-Chun , Fan Hsiang-Hsuan , Ou Da-Liang , Liao Sheng-Chieh , Hsu Chiun , Liu Shing-Hwa , Cheng Ann-Lii 
Published: June 2012

Abstract
To meet high energy demand for proliferation, cancer cells rely more on aerobic glycolysis than on oxidative phosphorylation (OXPHOS). This aberrant cellular metabolism of cancer, well-known as the “Warburg effect”, may confer survival advantages and drug resistance to cancer cells. Pyruvate dehydrogenase (PDH) is the gatekeeper of OXPHOS, and is inhibited by pyruvate dehyrogenase kinase (PDK) through phosphorylation. Dichloroacetate (DCA), a synthetic PDK inhibitor, can reverse glycosis to OXPHOS through PDH activation, and has been used for the treatment of congenital lactic acidosis for more than 30 years. The present study explored whether modulating the Warburg effect by DCA can improve the efficacy of sorafenib (a multi-kinase inhibitor of Raf, VEGFR and PDGFR), the current standard systemic therapy for HCC. Modulation of the Warburg effect was evaluated by measurement of lactate in culture medium and PDH activity. In vitro growth-inhibitory effects were measured by median-effect analyses in a panel of human HCC cell-lines (Hep3B, Huh-7, Sk-hep1, HCC36 and HA22T) cultured in normoxic condition. In vivo growth-inhibitory effects were measured in both subcutaneous and orthotopic murine HCC xenograft models. Apoptosis was evaluated by flow cytometry (annexin V staining and subG1 fraction analysis) and the terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay. Expression of apoptosis-related proteins was analyzed by Western blotting. We found that DCA reduced lactate production and increased PDH activity in HCC cells in a dose-dependent manner, indicating switching glucose metabolism from glycolysis to OXPHOS. DCA (10–60 mM) induced synergistic growth-inhibitory and apoptotic effects with sorafenib in most HCC cell-lines tested. Nude mice carrying subcutaneously or intrahepatically implanted Hep3B cells were treated with vehicle, DCA 100 mg/kg /day (equivalent to the dosage used to treat lactic acidosis in human), sorafenib 10 mg/kg /day, and DCA plus sorafenib, via gavage for 21 days. DCA-sorafenib combination synergistically suppressed the tumor growth without advertently affecting the body weight of mice. Synergistic induction of apoptosis was shown by TUNEL assay. Our data suggest that modulation of aberrant cellular metabolism of HCC cells by DCA may improve the clinical efficacy of sorafenib. (Supported by grants NSC97-3112-B-002-012, NSC98-3112-B-002-007, and NSC98-3112-B-002-037)
Citation Information: Mol Cancer Ther 2009;8(12 Suppl):B97.
Abstract B99: Dysregulation of HMGCR and the mevalonate pathway in human cancers
Authors: Penn Linda Z. , Clendening James W. , Pandyra Aleksandra , Boutros Paul C. , Trentin Grace A. , Martirosyan Anna , Trudel Suzanne , Jurisica Igor 
Published: June 2012

Abstract
The importance of cancer metabolism has been appreciated for many years, but the intricacies of how metabolic pathways and oncogenic events overlap remains unclear. By understanding how metabolism contributes to tumorigenesis, we will be able to target these fundamental biochemical pathways and impact patient care.
The mevalonate (MVA) pathway, paced by its rate-limiting enzyme, hydroxymethylglutaryl coenzyme A reductase (HMGCR), is a metabolic pathway required for the generation of a number of fundamental end-products including cholesterol and isoprenoids. Despite being subject to years of extensive research from the perspective of coronary artery disease, the contribution of the MBA pathway to human cancer remains largely unexplored.
Intriguingly, we show that high mRNA levels of 5/6 MVA pathway genes, including HMGCR, correlate with poor prognosis in a meta-analysis of six large expression microarray datasets of primary breast cancer. Indeed, we show that deregulated expression of HMGCR, full-length or splice-variant, increases anchorage-independent growth and tumorigenesis of transformed cells when plated in soft agar or grown as xenografts, respectively. Moreover, we also show that ectopic expression of deregulated HMGCR drives tumorigenesis of non-transformed breast cells a well as normal murine myeloid progenitors. Advancing these studies to an independent tumor-type (multiple-myeloma), shows that loss of the classic feedback response to the blockbuster drugs known as statins, which inhibit HMGCR, further defines dysregulation of the MVA pathway. In addition, we show that this loss of feedback regulation distinguishes the subset of tumor cells that are highly sensitive to statin-induced apoptosis.
Taken together, our results suggest that HMGCR is a candidate metabolic oncogene and provides molecular rationale for further exploring HMGCR inhibitors as anticancer agents.
Citation Information: Mol Cancer Ther 2009;8(12 Suppl):B99.
Abstract C101: Subcellular distribution study by means of the inherent fluorescence of the investigational drug Triapine and its zinc(II) complex
Authors: Trondl Robert , Kowol Christian R. , Arion Vladimir B. , Jakupec Michael A. , Lichtscheidl Irene , Keppler Bernhard K. 
Published: June 2012

Abstract
The antineoplastic activity of α-N-heterocyclic thiosemicarbazones was discovered several decades ago. Currently the most promising drug candidate of this class of compounds is Triapine (3-aminopyridine-2-carboxaldehyde thiosemicarbazone, 3-AP), which entered several phase I and II clinical trials as an antitumor agent. We discovered that Triapine possesses intrinsic fluorescence properties. This enabled us to monitor for the first time the uptake and intracellular distribution of an α-N-heterocyclic thiosemicarbazone in living human cancer cells by fluorescence microscopy. In addition we synthesized the first zinc(II) complex [Zn(Triapine)Cl2]•HCl of Triapine, which shows fluorescence as well, compared its cytotoxicity in human cancer cells with that of the parental compound and studied the influence of metal complexation on intracellular distribution.
Triapine and its zinc complex were characterized spectroscopically. The UV-Vis spectrum of Triapine in water shows a maximum absorbtion band at 359 nm, whereas the maximum absorbtion of [Zn(Triapine)Cl2]•HCl is slightly shifted to 365 nm. The maxima of the emission spectra of both compounds are at 457 nm when irradiated at ex = 360 nm.
Fluorescence microscopy of living SW480 (colon carcinoma) cells treated with Triapine or [Zn(Triapine)Cl2]•HCl showed that both compounds have a striking affinity to the nuclear membrane and to an organelle structure in the cytoplasm, whereas the localization in the nucleus was strongly different. The zinc complex binds to substructures within the nucleus, which could be verified as nucleoli by immunostaining of the nucleolar protein fibrillarin and co-staining with [Zn(Triapine)Cl2]•HCl. On the contrary, a strong affinity of Triapine to the nucleoli was not detected.
The cytotoxic potencies of Triapine and [Zn(Triapine)Cl2]•HCl were determined in SW480 (colon carcinoma) and 41M (ovarian carcinoma) cells by means of the colorimetric MTT assay. The IC50 value of Triapine is 0.55±0.2 µM in SW480 cells and 0.45±0.03 µM in the 41M cell line. [Zn(Triapine)Cl2]•HCl showed IC50 values of 0.54±0.02 µM in SW480 and 0.52±0.02 µM in 41M cells. Comparing the two substances, no remarkable differences were observed.
Our results demonstrate that Triapine can be visualized with fluorescence microscopy in living cells without any conjugation of fluorophores. Furthermore our findings indicate that metal complexation leads to a different subcellular distribution. Additional studies are ongoing to clearify the influence of metal complexation on the mode of action.
Citation Information: Mol Cancer Ther 2009;8(12 Suppl):C101.
Abstract C103: In vitro and in vivo anticancer activity of the new ruthenium compound KP1339 against human liver cancer models
Authors: Heffeter Petra , Atil Bihter , Jungwirth Ute , Koerner Wilfried , Micksche Michael , Keppler Bernhard K. , Berger Walter 
Published: June 2012

Abstract
KP1339 is a promising ruthenium based anti-cancer compound. Aim of this study was to test the in vitro and in vivo activity of KP1339 against human liver cancer. As a first step, the cytotoxic potential of KP1339 against a panel of hepatoma cell lines was determined by MTT assay. After 72 h treatment, the mean IC50 value was 124.4 µM with HCC1.2, and HCC3 being most sensitive (IC50 values of 62.9 µM and 67.5 µM, respectively). Notably, the IC50 values did not correlate with intracellular KP1339 levels determined by inductively-coupled plasma mass spectrometry (ICP-MS) measurements. All tested cell lines revealed similar Ru contents (∼5 ng Ru/105 cells) after 1 h drug exposure. To evaluate the mechanisms underlying KP1339 activity, apoptosis induction as well as impact on cell cycle distribution and proliferation of Hep3B cells was evaluated. KP1339 treatment led to typical morphological signs of programmed cell death like cell shrinkage, chromatin condensation and formation of apoptotic bodies. Apoptotic cell death induced by KP1339 was further characterized by PARP cleavage. An increase of cells with mitochondrial membrane depolarization (measured by JC-1 staining and FACS analysis) suggested that at least part of the observed apoptotic cell death is induced via the mitochondrial pathway. Furthermore, KP1339 treatment was found to significantly reduced DNA synthesis rate measured by 3H-thymidine incorporation. With regard to cell cycle distribution, 24 h treatment led to increase of cells in G2/M phase (detected by PI-staining followed by FACS analyses). This was accompanied by strong phosphorylation of the stress kinase P38 and the extracellular signal-regulated kinase (ERK), suggesting that P38 might be involved in delayed apoptosis entry. Currently the activity of KP1339 against several hepatoma cells is evaluated in xenograft experiments using female SCID mice (30 mg/kg i.v.; once a week for two weeks) as compared to the standard therapy Sorafenib (25mg/kg p.o.; five times a week for two weeks). Preliminary results indicate that KP1339 is well tolerated. In the Hep3B model, KP1339 led to a 2.4-fold increase in life span (mean survival of 80 days as compared to 33 days) and thus was superior to Sorafenib monotherapy (1.9-fold survival increase; 60 days as compared to the control). Taken together, KP1339 is a very promising anticancer drug with significant activity against human hepatoma cell lines in vitro and in vivo.
Citation Information: Mol Cancer Ther 2009;8(12 Suppl):C103.
Abstract C108: A novel mitotic kinesin Eg5 inhibitor exerts the growth-inhibitory effect in cancer cells in a manner independent of induction of monoastral formation but dependent of KRAS mutation status
Authors: Tanaka Toshimitsu 
Published: June 2012

Abstract
Mitotic kinesin Eg5 plays an important role in mitosis, as it is critical for proper bipolar spindle assembly. After the discovery of the first Eg5 inhibitor monastrol, a number of Eg5 inhibitors have been developed as anticancer drugs. We have previously synthesized a series of S-trityl-L-cysteine (STLC) derivatives as Eg5 inhibitors and demonstrated potent inhibitory effect on Eg5 ATPase activity and induction of mitotic arrest with characteristic monoastral spindles in HeLa cells. In this study, we evaluated the growth-inhibitory acitivities of novel STLC derivatives, Compound1, Compound2, and Compound3 by MTT assay in a wide range of human cancer cell lines derived from gastric (MKN1, MKN45, MKN74, NUGC3, NUGC4, NCI-N87), colon (C170, DLD1, HCT15, COLO205), pancreatic (AsPC1, BxPC3, SUIT2) and lung (PC-9, PC-14, H1975, H441, A549) cancers and investigated possible predictive biomarkers. Among the derivatives, Compound3 showed the most potent growth-inhibitory effect and sensitivity between cell lines showed marked differences, with IC50 values ranging from 0.134 to 7.14 M. Pancreatic cancer cell line AsPC1 and non-small cell lung cancer (NSCLC) cell lines H441 and A549 which harbor KRAS mutation showed relatively high IC50 values compared to other cell lines without KRAS mutation. Compound3 induced G2/M arrest in all cell lines as early as 8 hours after the treatment by flowcytometry, while the increase of the apoptotic sub-G1 fraction was not observed in these AsPC1, H441 and A549 cells harboring KRAS mutation. These results suggested that differential sensitivity to Compound3 and attenuated induction of apoptosis by Compound3 were attributed to KRAS mutation. Induction of monoastral spindles formation by Compound3 was observed as early as 8 hours after the treatment not only in sensitive cell lines but in refractory cell lines such as AsPC1 and H441 cells by immunocytochemistry, suggesting the induction of monoastral spindles formation does not work as a predictive biomarker for clinical development. There was no correlation observed between the growth-inhibitory effect and the basal Eg5 expression level of each cell line by western blot analysis. No significant difference was observed in the induction of a spindle checkpoint kinase BubR1 phosphorylation among the cells, a possible predictive biomarker in response to the Eg5 inhibitor treatment by western blot analysis.
Taken together, a novel mitotic kinesin Eg5 inhibitor Compound3 should be considered for further exploration and development and KRAS mutation status was suggested to be a candidate for a predictive biomarker of poor response to Eg5 inhibitors.
Citation Information: Mol Cancer Ther 2009;8(12 Suppl):C108.
Abstract C113: p21 downregulation is an important component of PAX3/FKHR oncogenicity and its reactivation by histone deacetylase inhibitors enhances combination treatment
Authors: Hecker Regina , Amstutz Ralf A. , Wachtel Marco , Walter Dagmar , Niggli Felix K. , Schafer Beat W. 
Published: June 2012

Abstract
A number of drugs developed against cancer-specific molecular targets have been shown to offer survival benefits alone or in combination with standard treatments, especially for those cases where tumor pathogenesis is dominated by a single molecular abnormality. One example for such a tumor type is alveolar rhabdomyosarcoma (aRMS) which is characterized by a specific translocation creating the oncogenic PAX3/FKHR transcription factor, believed to be the main molecular basis of the disease. Recently, we were able to demonstrate that the small molecule inhibitor PKC412 exhibits strong antitumor activity against aRMS by reducing the transcriptional activity of PAX3/FKHR.
In the present study, we screened for combination strategies that are superior to PKC412 treatment alone. Interestingly, we found that the combination of PKC412 with histone deacetylase (HDAC) inhibitors like valproic acid (VPA) synergistically induced apoptosis resulting in suppressed aRMS tumor growth in vivo.
We provide evidence that the enhanced antitumor effect upon combination treatment is achieved by VPA-induced reactivation of p21 which is downregulated in aRMS tumor cells via destabilization of its transcriptional regulator EGR1 by PAX3/FKHR. This identifies downregulation of p21 as a crucial event in PAX3/FKHR oncogenicity. Our study not only highlights a possible mechanism behind the increased efficacy of combination treatment but also indicates that different levels of PAX3/FKHR oncogenicity can be exploited therapeutically by a specific combination of anticancer drugs to increase their therapeutic potential.
Citation Information: Mol Cancer Ther 2009;8(12 Suppl):C113.