bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 1305: Fulvestrant induces the expression/activity of UGT1A4 in HepG2 cells: potential interactions with other therapeutic agents
Authors: Edavana Vineetha Koroth , Dhakal Ishwori B. , Yu Xinfeng , Williams Suzanne , Kadlubar Susan A.
Published: June 2012

Fulvestrant (Faslodex™) is a pure antiestrogen that has been shown to be effective in treating estrogen receptor (ER) positive tumors that are resistant to selective estrogen receptor modulators (SERMs) such as tamoxifen. Currently, clinical trials investigating the utility of adding fulvestrant to other therapeutics are being conducted. While co-administration of these drugs has not been shown to affect cytochrome P450-mediated metabolism of either drug, effects of co-administration on Phase II metabolism (i.e. glucuronidation) have not been explored.

We demonstrated that fulvestrant up-regulates expression of UDP glucuronosyltransferase (UGT) 1A4, the major enzyme responsible for the direct conjugation and subsequent elimination of many therapeutic drugs. Endogenous mRNA expression levels of UGT1A4 in HepG2 cells were induced 4.5-fold by fulvestrant treatment in this ERα-expressing cell line. Treatment with fulvestrant upregulated UGT1A4 in a time- (0-72 hours) and concentration-(0-250 nM) dependent manner and silencing ERα with specific siRNA abolished UGT1A4 up regulation. The role of a Sp1 binding site (−1906 to -1901 base pairs), known to be critical for the induction of UGT1A4 transcriptional activity by estradiol, was examined in relation to fulvestrant-mediated induction of UGT1A4. Electrophoretic mobility shift assays were performed using these nuclear extracts and UGT1A4/Sp1 probe. Fulvestrant-treated HepG2 nuclear extract formed multiple shifted bands that appear to represent homomultimeric complexes of Sp1 with UGT1A4/Sp1 probe. This binding ability was partially blocked by mithramycin, a known inhibitor of Sp1 binding to DNA.

While these in vitro assays indicate that fulvestrant administration could influence the disposition of other UGT1A4 substrates, the clinical significance of these findings is unclear. Further studies are needed to assess the effects of fulvestrant administration on the disposition of drugs that are substrates of UGT1A4, including anastrozole, clozapine, imipramine, irinotecanl, amotrigine, meperidine, midazolam, nicotine, olanzapine, SN-38 and tamoxifen.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1305. doi:10.1158/1538-7445.AM2011-1305
Abstract 1306: A Phase 1b/2a study of CRLX101, a novel nanopharmaceutical of camptothecin, in solid tumor cancer patients who have failed standard therapy
Authors: Weiss Glen , Yen Yun , Neidhart Jeffrey , Young Cissy S. , Weiss Sara , Ryan John
Published: June 2012

Results from a 24-patient dose-escalation safety and tolerability Phase 1 study of CRLX101 were presented at the 22nd EORTC-NCI-AACR symposium in November 2010. A Phase 2a expansion study of CRLX101 has been initiated to investigate the biological activity and tolerability in cancer patients with specific tumor types at the maximum-tolerated dose (MTD) of 15 mg/m2. Specifically, a focus of the Phase 2a expansion study is to evaluate CRLX101 biological activity in non-small cell lung carcinoma (NSCLC), amongst other target indications.

In this Phase 2a expansion study, thirty-six (36) patients will be enrolled from three (3) clinical sites in the United States. Fifteen (15) patients treated with CRLX101 thus far were patients with advanced NSCLC. Stable disease of greater than 6 months in multiple NSCLC patients treated with CRLX101 has been observed. Dose-limiting bone marrow toxicities of thrombocytopenia and neutropenia were addressed with the longer dosing interval of an every-other-week dosing schedule, which accommodates for the prolonged half-life of CRLX101. Hemorrhagic cystitis, the classic camptothecin toxicity, has not been observed. No other significant adverse events have been observed in the current study.

The Phase 2a study will be fully enrolled by the end of 2010 with extensive follow-up on most patients by April of 2011. All of the safety, tolerability, and biological activity data will be presented. At this time, twenty-one (21) of the thirty-six (36) patients have been enrolled. To date, three (3) NSCLC patients have received 4 cycles of therapy and are continuing on study. One (1) NSCLC patients is receiving the seventh cycle of therapy.

A controlled, randomized Phase 2 study of CRLX101 in NSCLC is planned and will be initiated in early 2011. CRLX101's favorable tolerability profile may enable combination therapy with other cytotoxic drugs including carboplatin and gemcitabine without added toxicities. Preclinical data on the efficacy and tolerability of such combinations will also be presented. In addition, the dual activity of CRLX101 against both topoisomerase-1 and HIF1α suggest that combination with VEGF antagonists could be synergistic. Similarly, pre-clinical data on the dual mechanism inhibition by CRLX101 based on its pharmacokinetics will be presented.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1306. doi:10.1158/1538-7445.AM2011-1306
Abstract 1322: Molecular mechanisms of high glucose-induced toxicity in human breast adenocarcinoma (Mcf-7) cells
Authors: Yedjou Clement G. , Tchounwou Christine K. , Tchounwou Paul B.
Published: June 2012

Glucose is a simple sugar that your body relies on it to produce energy. It has been shown that high glucose is related to many long-term health problems including the kidneys, nerves, eyes and vision, risk of heart disease and stroke, erectile dysfunction in men and pregnancy complications in women. Epidemiological data have suggested an increased cancer rates in diabetic patients, for which the underlying mechanism is poorly understood. Hence, the aim of the present investigation was to evaluate the cell viability of human breast adenocarcinoma (MCF-7) cells exposed to different doses (0, 5, 10, 20, 40, 80 mg/mL) of D-glucose by the means of trypan blue exclusion test and MTT assay, respectively. The degree of DNA damage and early stage apoptosis were also tested by the means of alkaline single cell gel electrophoresis (Comet) assay, and flow cytometric analysis using Annexin V FITC/PI. The results of MTT assay indicated that low dose (5 mg/mL) of D-glucose slightly increase cell viability upon 2 h of exposure. On the other hand, high doses (10-80 mg/mL) of D-glucose significantly reduce the viability of MCF-7 cells in a dose and time-dependent manner. Similar trend was obtained with the trypan blue exclusion test. Data obtained from the comet assay indicated that D-glucose causes DNA damage in MCF-7 cells in a dose-dependent manner. The flow cytometric assessment (Annexin V FITC/PI) showed a strong dose-response relationship between high glucose exposure and annexin V positive cells undergoing early stage apoptosis in MCF-7 cells. Based on these direct in vitro findings, our study shows clear evidence that elevated level of D-glucose induced cytotoxic and genotoxic effects, and apoptosis in MCF-7 cells. This finding provides evidence that elevated level of glucose may be is associated with diabetic complications in vascular endothelium of the female breasts.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1322. doi:10.1158/1538-7445.AM2011-1322
Abstract 1332: Cigarette smoking attenuates TGF-β-mediated tumor suppression function through down-regulation of Smad3 in lung cancer
Authors: Samanta Debangshu , Gonzalez Adriana , Datta Pran K.
Published: June 2012

Cigarette smoking has been connected to an array of chronic lung diseases and one of the major causes of morbidity and mortality. Epidemiological studies have demonstrated the most cases of lung cancers (85-90%) are directly attributable to tobacco smoking. Although much information is gained about the effect of cigarette smoking on various signaling pathways causing lung cancer, no information is available about the effect cigarette smoking on the TGF-β-dependent initiation and progression of lung cancer. To address this issue, A549, a lung adenocarcinma cell line and HPL1A, an immortalized lung epithelial cell line were chronically treated with cigarette smoke condensate (CSC) to mimic the conditions of long-term cigarette smoking. Prolonged exposure of these cells to CSC resulted in a decrease in Smad3 and Smad4 complex formation and TGF-ß-mediated transcription due to reduced expression of Smad3. As a consequence, the cells were less apoptotic, were more viable, and lost TGF-β mediated growth inhibition. We found that the decrease in apoptosis is due to the up-regulation of Bcl2, which is a downstream target of Smad3. The repression of Smad3 expression is at the promoter level and is due to histone deacetylation. Withdrawal of CSC treatment resulted in the restoration of Smad3 expression, reduction in cell viability and increased TGF-β mediated growth inhibition. Rescue experiment with reintroduction of Smad3 in the 300 day CSC treated cells restored TGF-β signaling, increased apoptosis and decreased cell viability. Finally, three hundred days CSC exposure dramatically increased the tumorigenicity of cells in vivo, and Smad3 re-expression reverses this effect. In patient samples, there is a trend that expression of Smad3 goes down in smokers compared to non-smokers. Collectively, these data provide evidence that cigarette smoking promotes tumorigenicity partly by abrogating TGF-β mediated growth inhibition and apoptosis by reducing expression of Smad3.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1332. doi:10.1158/1538-7445.AM2011-1332
Abstract 1334: Benzo(a)pyrene concentration-dependent biotransformation and cytotoxicity in HT-29 colon cells
Authors: Myers Jeremy , Ramesh Aramandla
Published: June 2012

The majority of sporadic cancer deaths are attributed to environmental factors of which exposure to environmental toxicants is one. Benzo(a)pyrene (BaP), a member of the Polycyclic Aromatic Hydrocarbons (PAH) family of compounds is one such ubiquitous environmental toxicant; found in charcoal broiled/smoked meats, cigarette smoke, automobile exhaust, and industrial emissions. High levels of BaP have been detected in fat-rich foods such as dairy products, barbecued pork sausage, and beef meat. Since diet makes up a substantial amount of BaP intake (∼ 3 – 17 mg/person/day); ingested BaP contributing to gastrointestinal (GI) carcinogenesis deserves attention. Studies conducted using a mouse model in our laboratory has already shown that BaP contributes to colon cancer development. Through metabolic activation, BaP is biotransformed into an array of metabolites. Biotransformation of BaP proceeds through specific biochemical pathways (epoxide and quinone) each one producing specific reactive metabolites that bind with DNA, cause DNA damage and associated changes in cell cycle. The objective of this study was to determine the concentrations of BaP that are most toxic to HT-29 human colon cells and examine if any relationship exist between cellular toxicity and BaP biotransformation. Cells were cultured in Dulbecco's Modified Eagle Medium: Nutrient Mixture F-12 (DMEM/F12) supplemented with 10% FBS and antibiotics (penicillin/streptomycin). After revival of cells and growing them to confluence, cells were synchronized overnight by serum starvation method. The HT-29 cells were exposed to 1, 5, 10, 25, 50, and 100μM BaP over the course of 10 days and then counted using a Coulter Counter. Based on a concentration – response study 5, 10, and 25 μM BaP in DMSO (vehicle for BaP; 0.01%) were selected as optimal concentrations to analyze the effect of BaP on cell growth, viability, biochemical, and molecular endpoints 4 days after BaP exposure. The expression of both Phase I and II drug metabolizing enzymes were analyzed by western blot and RT-PCR. Analysis of cell cycle via FACS showed inhibition of the S and G2-phase in cells treated with increasing concentrations of BaP. An increase in CYP 1A1 and 1B1 expression also occurred in a BaP concentration-dependent manner. However, not much difference was seen in Phase II metabolizing enzyme expression levels regardless of the BaP concentrations tested. Our results suggest that BaP cytotoxicity is mediated by metabolic activation (funded by the NIH grants 5T32HL007735-12, 1RO1CA142845-01A1, 1S11ES014156-01A1 and Southern Regional Education Board).

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1334. doi:10.1158/1538-7445.AM2011-1334
Abstract 1335: Phosphorylation of serine 9 is required for benzo(a)pyrene induced GNMT nuclear translocation
Authors: Lu Yao-Cheng , Yen Chia-Hung , Lai Xiu-Ting , Chen Yi-Ming A.
Published: June 2012

Glycine-N-methyltransferase (GNMT) is a protein with multiple functions. It can affect genetic stability by (1) regulating the ratio of S-adenosylmethionine to S-adenosylhomocystine and (2) binding to folate. In addition to act as a tumor suppressor for liver cancer, GNMT participated in the detoxification pathway by interacting with environmental carcinogens [such as benzo(a)pyrene (BaP), aflatoxin B1 (AFB1)] and decreasing subsequent DNA adducts formation and cytotoxicity. GNMT was primarily expressed in cytoplasm and partially translocated to cell nuclei after BaP treatment. Despite the mechanism of GNMT nuclear translocation remains unclear, it has been shown that the phosphorylation modification is important for GNMT nuclear translocation. The results from LC-MS/MS (liquid chromatography-tandem mass spectrometry) analysis showed that serine 9 of GNMT was phosphorylated after BaP treatment. The GNMTS9A mutant did not undergo nuclear translocation after BaP treatment by using indirect immunofluorescence assay. GNMT serine 9 was identified within an Akt1 consensus site by Scansite program. The co-immunoprecipitaion assay demonstrated that GNMT interacts with Akt. Akt phosphorylated GNMT only on serine 9 in vitro. Furthermore, BaP induced GNMT nuclear translocation was blocked by LY294002 treatment. In conclusion, the results suggested that the Serine 9, can be phosphorylated by Akt1, is an important phosphorylation site responsible for GNMT nuclear translocation after BaP treatment.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1335. doi:10.1158/1538-7445.AM2011-1335
Abstract 1350: Novel ABI analogs target the colchicine site in tubulin and overcome multidrug resistance in metastatic melanoma
Authors: Li Wei , Chen Jianjun , Wang Zhao , Li Chien-Ming , Lu Yan , Dalton James T. , Miller Duane
Published: June 2012

With rapidly rising incidences of metastatic melanoma and its high resistance to current therapeutic agents, developing more effective drugs is urgently needed. We recently discovered a novel class of 2-aryl-4-benzoyl-imidazoles (ABI) analogs. These compounds showed great antiproliferative activity on melanoma cells and the IC50 is as low as 8 nM. ABIs showed equal potency against multidrug resistant melanoma cells and the sensitive parent cells, suggesting that they can effectively overcome P-gp meditated multidrug resistance. ABIs inhibited capillary network formation which indicates high potential for anti-angiogenesis. Cell cycle analysis showed ABIs arrested cells in the G2/M phase and inhibited tubulin polymerization. ABIs bind to the colchicine binding site in the α/β-tubulin heterodimer as indicated by a number of evidences including competitive binding and molecular modeling studies. Immunofluorescence experiments revealed that microtubule modality was dramatically changed with ABIs treatment. In vivo studies using both B16-F1/C57BL model and A375/SHO model showed significant inhibition of melanoma tumor growth by ABIs. These novel analogs hold great promise as new selective agents for the improved treatment of malignant melanoma.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1350. doi:10.1158/1538-7445.AM2011-1350
Abstract 1352: Mechanism of action of AL622, a molecule rationally designed to release an EGFR and a Src kinase inhibitor
Authors: Ning Na , Larroque-Lombard Anne-Laure , Huang Ying , Rao Suman , Jean-Claude Bertrand J.
Published: June 2012

In many solid tumors, including prostate and breast carcinomas, it has now been shown that Src synergizes with EGFR to promote cell proliferation and invasion. While molecules with EGFR and Src targeting functions have been designed, prodrugs capable of releasing optimized inhibitors of the two targets are scant. We designed AL622, which contains a quinazoline head targeted to EGFR and a hydrolysable linker that connects it to the PP2-like structure. HPLC analysis showed that this molecule is capable of releasing an EGFR inhibitor and intact PP2 inside the cells. The growth inhibition of AL622 in a panel of isogenic NIH3T3 cell lines (wt, Neu/ErbB2 and Her14/EGFR transfected) in comparison with Gefitinib (a clinically approved strong EGFR inhibitor) and PP2 (a Src-inhibitor) was assessed using the SRB assay. Like Gefitinib, AL622 blocked the proliferation of NIH3T3 cells transfected with the EGFR or Her2 gene. Although Gefitinib was twice as potent, AL622 showed a higher selectivity (fold selectivity = 1.77 for Neu-transfected and 1.63 for HER14-transfected cells). On the other hand, AL622 showed a 5-fold greater potency than PP2 in the EGFR and Her2 transfected cells. It was also much more selective than PP2 (fold selectivity = 35.9 for Neu-transfected and 37.8 for HER14-transfected cells). Western blot analysis in MDA-MB231 cells known to be characterized by Src-EGFR interaction showed that AL622 was capable of inducing a dose-dependent inhibition of EGFR and Src. In contrast, PP2 at an equidose was incapable of blocking EGFR but induced potent Src-inhibition. While Gefitinib induced some Src inhibition, it was less potent than AL622. Results from the wound healing assay showed that AL622 was capable of blocking the motility of 4T1 mouse breast cancer cells at doses comparable with those of PP2. However, a Boyden Chamber invasion assay showed that AL622 was capable of inducing more significant inhibition of invasion when compared with PP2 or the combination of PP2 and Gefitinib. The results in toto suggest that designing molecules to inhibit Src and EGFR can be an effective strategy to block aggressive proliferation and invasion in tumor cells.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1352. doi:10.1158/1538-7445.AM2011-1352
Abstract 1357: Inhibition of breast cancer cell growth by a synthetic ligand targeting the nuclear receptor, REV-ERB (NR1D1 and NR1D2)
Authors: Wang Yongjun , Kamenecka Theodore , Kojetin Douglas , Burris Thomas P.
Published: June 2012

Disruption of the circadian rhythm leads to increased risk for development of breast cancer in humans. The molecular mechanism underlying the link between circadian rhythm disruption and the increased risk of breast cancer in humans is not clear. The REV-ERBs are nuclear receptors that function as critical regulatory components of the circadian rhythm. We observed that REV-ERBbeta is highly overexpressed in multiple breast cancer cell lines, but not in the non-tumorigenic control breast cell line, MCF-10A. Furthermore, we show that a synthetic REV-ERB agonist that we discovered, SR9011, inhibits the proliferation of multiple breast cancer cell lines including triple negative breast cancers but has no effect on MCF10A cells. We discovered that the REV-ERBs directly regulates the expression of cyclin A2 gene suggesting a possible mechanism for inhibition of proliferation. Treatment of breast cancer cell lines with SR9011 repress the expression of cyclin A2 at both mRNA and protein levels. SR9011 treated SKBR3 cells display a reduced fraction of cells in S phase and in the G2/M phase. Administration SR9011 to synchronized SKBR3 cells results in about 8 hours delay of G2/M phase occurrence. Thus, our data suggests that REV-ERB is a valid target for development of anti-cancer agents and SR9011 holds promise for treatment of breast cancer.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1357. doi:10.1158/1538-7445.AM2011-1357
Abstract 1359: Identification of a novel class of compounds as proteasome inhibitors: Synthesis and structure activity relationship studies of PI-1833 library
Authors: Ozcan Sevil , Aslamuzzaman Kazi , Marsilio Frank , Daniel Kenyon , Brooks Wesley , Guida Wayne , Lawrence Harshani , Sebti Said
Published: June 2012

The ATP-dependent ubiquitin-proteosome pathway is responsible for the controlled degradation of proteins in eukaryotic cells. The 26S proteosome is a multifunctional complex, consisting of a 19S regulatory particle (RP) and a 20S core particle (CP). The three main catalytic activities of the proteasome; peptidylglutamyl peptide hydrolysing (PGPH), trypsin-like (T-L), and chymotrypsin-like (CT-L), are mediated by three distinct catalytic β-1, β-2, and β-5 subunits, respectively. Owing to the central role of proteosome in maintaining homeostasis and hence its key position in many cellular processes, the development of inhibitors for CT-L activity has been the subject of considerable interest in the treatment of cancer. Selective inhibition of the CT-L activity of 20S proteasome represents a successful strategy in cancer therapy as demonstrated by Bortezomib (Velcade), a clinically approved drug for multiple myeloma and mantle lymphoma. Toxicity and tumor cell resistance against Bortezomib demand the development of improved and selective proteasome inhibitors. The potent proteasome inhibitors reported to date have been developed as aldehydes, boronates, vinylsulfones and expoxyketones and these compounds function through covalent modification of the N-terminal threonine residue of β-5 subunit. Small, drug-like synthetic proteasome inhibitors that are selective for cancer over normal cells are rare, but clearly would have a potential advantage over the existing inhibitors. PI-1833 was identified in our program as a ‘hit’ with in-vitro CT-L proteasome activity (IC50 = 0.58 μM). PI-1833 is a small molecule with oxadiazole pharmacophore and presents 3 points of diversity amenable for focused library synthesis. Lack of a reactive chemical moiety (or electrophilic moiety) to form proteasome adducts is an important feature of PI-1833. The first generation analogs of PI-1833 have shown promising SAR (in-vitro and in-vivo) toward proteasome inhibition with the IC50 values ranging from 0.3-0.7 μM. In this work we will present in-vitro and in-vivo structure activity relationship (SAR) data, synthesis and selectivity of a PI-1833 library and discuss the mode of proteasome inhibition (co-valent vs non co-valent) by this class of compounds.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1359. doi:10.1158/1538-7445.AM2011-1359
Abstract 1361: Fragment based drug discovery of selective inhibitors of Fibroblast Growth Factor Receptor (FGFR)
Authors: Saxty Gordon , Akkari R , Angibaud P , Arts J , Benderitter P , Berdini V , Bonnet P , Cleasby A , Embrechts W , Freyne E , Gilissen R , King P , Lacrampe J , Ligny Y , Madin A , Mcclue S , Mevellec L , Murray C W. , Newell H , Page M , Papanikos A , Perera T , Querolle O , Rees D C. , Rich S J. , Saalau-Bethell S M. , Sement E , Simmonet Y , Squires M , Tronel V , Ward G A. , Willems M , B Wroblowski , Thompson N T.
Published: June 2012

Recent data in a number of tumour types has implicated Fibroblast Growth Factor (FGF) and Fibroblast Growth Factor receptor (FGFR) signalling as being key to the molecular pathology of cancer.

A fragment screening campaign was conducted against the tyrosine kinase domain of FGFR1 to detect low molecular weight compounds that bound to the hinge region of the kinase. The screening produced several fragment inhibitors (molecular weight <250 Da) in the micromolar range and their binding modes were confirmed by X-ray crystallography. We selected an imidazo[1,2-a]pyridine fragment that was 120 uM versus FGFR3 in the kinase inhibition bioassay. Subsequently, in the fragments-to-leads stage a detailed structural understanding of the binding interactions between the fragment and its protein kinase target, using X-ray crystallography, led to the identification of a 0.003 uM inhibitor of FGFR3 in the kinase bioassay, with significant selectivity versus VEGFR2 and FLT3.

The poster will focus on the description of previously undescribed compounds bearing an imidazo[1,2-a]pyridine core scaffold where selectivity versus other protein kinases, for example FLT3, is obtained using the X-ray crystal structure and structure-based design. In summary we will illustrate how X-ray crystallography and fragment-based drug design (FBDD) can be used to discover compounds with activity in an FGFR driven xenograft model when dosed by the oral route.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1361. doi:10.1158/1538-7445.AM2011-1361
Abstract 1373: Identification of potential anti-tumor therapeutics targeting the Six1 transcriptional complex
Authors: Blevins Melanie , An Jianghong , Jones Steven , Swaroop Manju , Ferrer Marc , Ford Heide , Zhao Rui
Published: June 2012

Six1, a homeobox gene highly expressed during embryogenesis, is later down-regulated in most adult tissues. Six1 over-expression in adult tissues plays a causal role in the onset and progression of a significant proportion of breast and other cancers, as illustrated by its over-expression in 50% of primary breast tumors and 90% of metastatic sites. This selective over-expression establishes the Six1 gene as an attractive target for future anti-cancer therapeutics. To date, most breast cancer therapies do not specifically target cancerous cells and have considerable side effects. Therefore, it is important that new therapies are developed with specificity for cancerous cells and with fewer side effects. We hypothesize that molecules targeting the Six1 transcriptional complex can inhibit tumor cell proliferation and metastasis in breast cancer with limited side effects. Six1 requires the Eya family of co-activator proteins to activate transcription. Eya2 seems to be the most relevant Eya family member in breast tumorigenesis. Since single amino acid mutations have been shown to significantly reduce the Six1/Eya2 interaction, we hypothesize that this interaction can be disrupted by small molecules. We propose that disruption of the Six1/Eya2 interaction would greatly diminish the effects of Six1 activation in cancerous cells. Therefore, we developed a HTS assay to identify small molecule inhibitors of the Six1/Eya2 interaction. Additionally, screening of 33 compounds identified through an in silico screen in collaboration with the Michael Smith Genomics Center identified a promising lead compound that inhibits the Six1/Eya2 interaction. The lead compound is presently being evaluated for its efficacy, specificity, and mechanism of action using structural, biochemical, and cell-based assays. In addition, we have begun structure activity relationship studies to further optimize our lead compound.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1373. doi:10.1158/1538-7445.AM2011-1373
Abstract 1389: Cyr61 increases cell migration in human oral cancer cells through FAK, ERK and NF-κB pathways
Authors: Yu Nuo-Yi , Chuang Jing-Yuan , Hsieh Chin Hsuan , Tang Chih-Hsin
Published: June 2012

Cysteine-rich 61 (Cyr61), from the CCN gene family, is a secreted and matrix-associated protein, which is involved in many cellular activities such as growth and differentiation. Most of CCN family can regulate the cell motility, division and adhesion. However, the effect of Cyr61 on migration activity in human oral squamous carcinoma cells is mostly unknown. Here, we found that Cyr61 increased the migration in human oral squamous carcinoma cells (SCC-4 cells). Activations of focal adhesion kinase (FAK), extracellular signal-regulated kinase (ERK) and NF-κB pathways after Cyr61 treatment was demonstrated, and Cyr61-induced migration activity was inhibited by specific inhibitor of ERK and NF-κB cascades. Transfection of cells with FAK, ERK, IKKα(IkappaB kinase alpha) and IKKβ mutant also reduced Cyr61-mediated cancer migration. Taken together, our results suggest that Cyr61 acts through FAK/ERK, which in turn activates NF-κB, contributing to the migration of human oral squamous carcinoma cells.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1389. doi:10.1158/1538-7445.AM2011-1389
Abstract 1390: Endothelin-1/ETBR axis promote COX-2 production and migration in human chondrosarcoma cells through MAPK and AP-1 pathways
Authors: Wu Min Huan , Lin James A , Huang Chih-Yang , Tang Chih-Hsin
Published: June 2012

Chondrosarcoma is a type of highly malignant tumor with a potent capacity to invade locally and cause distant metastasis. Endothelin-1 (ET-1) the most potent vasoconstrictor, plays a crucial role in migration and metastasis of human cancer cells. Cyclooxygenase (COX)-2 has been implicated in tumor metastasis. However, the effects of ET-1 in migration and COX-2 expression in chondrosarcoma cells are largely unknown. The aim of this study was to investigate whether ET-1 is associated with the motility of human chondrosarcoma cell. We found that treatment of human chondrosarcoma cells (JJ012 cells) with ET-1 increased migration and expression of COX-2. Activations of MAPK (p38, JNK and ERK) and activator protein-1 (AP-1) pathways after ET-1 treatment were demonstrated, and ET-1-induced expression of COX-2 and migration activity was inhibited by the specific inhibitor and mutant of Endothelin B receptor (ETBR), MAPK and AP-1 cascades. Moreover, ET-1 increased the binding of c-Jun to the AP-1 element on the COX-2 promoter. ETBR and MAPK inhibitor reduced ET-1 mediated binding activity and AP-1 luciferase activity. Taken together, our results indicated that ET-1 enhances the migration of chondrosarcoma cells by increasing COX-2 expression through the ETBR axis, MAPK and AP-1 signal transduction pathways.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1390. doi:10.1158/1538-7445.AM2011-1390
Abstract 1410: TIP-1 regulates Glioma invasion through small GTPases
Authors: Wang Hailun , Han Miaojun , Hallahan Dennis E. , Han Zhaozhong
Published: June 2012

Therapy resistance and invasion are two common features of malignant glioma. Our previous studies showed that TIP-1 regulates sensitivity of glioma cells to ionizing radiation. It was also found that TIP-1 protein level was elevated in human malignant glioma compared to the normal brain tissue counterparts, and correlated with the malignancy of gliomas. This observation was supported with a survival study within animal models, in which TIP-1 knockdown within glioma cell lines significantly retarded progression of the intracranially implanted tumors and extended survival time of the mice. In vitro and in vivo studies indicated that it is the reduced migration and invasion capability, but not the cell proliferation rate, that contributed to the retarded tumor progression of gliomas with TIP-1 knockdown. The glioma cells with TIP-1 knockdown also showed morphological changes with reorganized cytoskeleton and reduced efficiency of reorientation in directional migration. TIP-1 was reported to associate to beta-catenin and Rhotekin, two proteins that are involved in the cell skeleton reorganization and cell migration. Their interactions are through the single PDZ domain within TIP-1 and the classic Type I PDZ-binding motifs located at the carboxyl terminus of beta-catenin and Rhotekin respectively. It was found that TIP-1 knockdown altered intracellular location of Rhotekin. Mislocalization of Rhotekin at the cell migration leading edge resulted in irregular activation of RhoA, which generally regulates cell rear body retraction. Further, we identified that beta-PIX shares a similar PDZ-binding motif and associates to TIP-1 in vitro and in vivo. Beta-PIX is recruited to the leading edge by Scribble for Rac1 or Cdc42 activation and thus regulates cell front protrusion. Knockdown of TIP-1 within the invasive glioma cells disrupted the association of beta-PIX and Scribble, resulted in mislocalization of beta-PIX and reduced Rac1 activation. Taken together, these data illustrated that TIP-1 is one critical modulator in migration of the invasive glioma through regulating two small GTPases (RhoA and Rac1), and targeting TIP-1 might represent one novel approach to treat the highly invasive and mortal glioma tumors.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1410. doi:10.1158/1538-7445.AM2011-1410
Abstract 142: Novel tumor suppressor role of microRNA-205 in melanoma via regulation of E2F1
Authors: Dar Altaf A. , Majid Shahana , Nosrati Mehdi , de Semir David , Bezrookove Vladimir , Kashani-Sabet Mohammed
Published: June 2012

MicroRNAs (miRNAs) regulate gene expression by repressing translation or directing sequence-specific degradation of complementary mRNA. Altered miRNA expression has been demonstrated in several human cancers. Limited information is available concerning the expression and role of miRNAs in melanoma. Here, we report that expression of miR-205 is significantly suppressed in melanoma tumor samples when compared with nevi, and is correlated inversely with melanoma progression. miR-205 expression was also significantly downregulated in a panel of melanoma cell lines when compared to a normal melanocyte line. miRNA target databases predicted a conserved target site for miRNA-205 in the 3’ untranslated region (UTR) of E2F1 and E2F5. The expression levels of E2F1 and E2F5 were inversely correlated with that of miR-205 in melanoma cell lines. miR-205 significantly suppressed the luciferase activity of reporter plasmids containing the 3’UTR sequences complementary to either E2F1 or E2F5, which was abolished by mutations in these 3’UTR regions. Overexpression of miR-205 in melanoma cells reduced E2F1 and E2F5 protein levels without alteration of mRNA expression. The proliferative ability of melanoma cells was suppressed by miR-205, mediated by E2F-regulated AKT phosphorylation. Transient overexpression of miR-205 in melanoma cells resulted in induction of apoptosis, as indicated by increases in cleaved caspase-3, poly-(ADP-ribose) polymerase (PARP) and release of cytochrome-c. Stable overexpression of miR-205 suppressed cell proliferation and colony formation, and resulted in inhibition of tumor cell growth in vivo and induction of a senescence phenotype accompanied by elevated p16INK4A expression and other markers for senescence. These results demonstrate a novel role for miR-205 as a tumor suppressor in melanoma.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 142. doi:10.1158/1538-7445.AM2011-142
Abstract 1434: Invasion of melanoma cells resistant to BRAF inhibition involves RHO-family GTPases
Authors: Klein Richard M. , Higgins Paul J.
Published: June 2012

Resistance to targeted therapies constitutes a major clinical obstacle that likely contributes to cancer recurrence following initial successful treatment. This study focused on the cellular responses associated with resistance to BRAF inhibition in an invasive melanoma cell line harboring a BRAFV600E mutation. Pharmacologic inhibitors targeting total or mutant-specific BRAF resulted in a dose-dependent reduction in phospho-MEK1/2 levels. Despite reduced ERK1/2 activation, viable melanoma cell subpopulations were present in cultures treated with BRAF inhibitors. Drug resistant cells were elongated and displayed prominent actin stress fibers. Melanoma cells resistant to BRAF inhibition were identified in both 2-D and 3-D cell cultures. Cells resistant to BRAF inhibition displayed reduced expression of RND3, an antagonist of RHOA activation. Restoration of RND3 expression or RHOA knockdown prevented actin cytoskeletal reorganization and attenuated the migratory ability of drug-insensitive cells without affecting cell survival. Additionally, the invasive ability of BRAF inhibitor resistance cells embedded in 3-D collagen gels was diminished following RND3 re-expression or RHOA depletion. Overall, these results describe previously uncharacterized roles for RND3 and RHOA in the ability of melanoma cells, treated with pharmaceutical BRAF inhibitors, to invade a dermal-like microenvironment. The molecular mechanisms learned from this information may assist in the development of strategies to improve overall therapeutic efficacy.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1434. doi:10.1158/1538-7445.AM2011-1434
Abstract 1436: The Cdk5 activator p39 specifically links muskelin to myosin and regulates stress fiber organization and contraction
Authors: Tripathi Brajendra K. , Lowy Douglas R. , Zelenka Peggy S.
Published: June 2012

Cyclin-dependent kinase 5 (Cdk5), a proline-directed serine/threonine protein kinase, regulates signaling pathways implicated in the adhesion and migration of various cell types. Activation of Cdk5 requires its association with its activators p35 or p39. We have recently shown, in lens epithelial cells, that Cdk5 kinase activity regulates rho-dependent myosin phosphorylation, cytoskeletal contraction, and cell migration by controlling Src-p190RhoGAP signaling. In a separate line of investigation, we demonstrated that the N-terminus of p39 binds myosin essential light chain (MLC), while the C-terminus of p39 binds muskelin, a multi-domain scaffolding protein. As both muskelin and MLC have been associated with cytoskeletal organization, the present study seeks to determine whether p39 might serve as an adaptor that links muskelin to myosin and to investigate the possible biological relevance of such an interaction. Immunoprecipitation studies demonstrated that muskelin forms a protein complex with p39, MLC, myosin regulatory light chain (MRLC), and myosin heavy chain II (MHC II). Suppressing expression of p39 abrogated the interaction between muskelin and the myosin subunits, demonstrating that p39 is required to link muskelin to myosin. Immunofluorescence staining showed that muskelin colocalized with MRLC and actin-containing stress fibers. Suppressing muskelin expression with either of two different siRNAs significantly reduced MRLC phosphorylation and disrupted stress fiber organization. Similar effects were observed when Cdk5 activity was inhibited or suppressed. Moreover, suppressing muskelin expression prevented any further reduction of MRLC phosphorylation when Cdk5 activity was blocked, indicating that muskelin plays an important role in Cdk5-dependent regulation of MRLC phosphorylation. The Cdk5 activating protein p39 was necessary and sufficient for Cdk5-dependent regulation of myosin phosphorylation, as suppression of p39, but not p35, significantly reduced MRLC phosphorylation. Together, these results demonstrate that the Cdk5 activating protein p39 specifically links muskelin to myosin and thus, to stress fibers. Therefore, p39 has a dual role in cytoskeletal regulation: on one hand, it is an integral subunit of Cdk5 kinase; on the other, it acts as an adaptor protein to recruit muskelin to stress fibers. Each of these p39 functions is required for myosin phosphorylation, cytoskeletal contraction, and efficient cell migration.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1436. doi:10.1158/1538-7445.AM2011-1436
Abstract 1438: Breast cancer metastasis suppressor 1 (BRMS1) suppresses attachment and spreading of breast cancer cells on 2D and 3D extracellular matrix components by altering focal adhesion-associated signaling
Authors: Khotskaya Yekaterina B. , Beck Benjamin H. , Hurst Douglas R. , Hung Mien-Chie , Welch Danny R.
Published: June 2012

Metastatic dissemination of cancer cells from primary tumor to secondary sites is a multi-step process that depends heavily on the ability of cancer cells to respond to the microenvironmental cues, such as changes in composition of surrounding extracellular matrix (ECM), by adapting their adhesion abilities and undergoing cytoskeletal rearrangement. Many of these interactions between cancer cells and ECM are mediated by signaling cascades initiated at the cell surface through activation of integrins and growth factor receptors. BRMS1, or Breast cancer Metastasis Suppressor 1, belongs to a family of metastasis suppressor genes and has been shown to affect several steps of the metastatic cascade. BRMS1-expressing cells shed by the primary tumor can enter the circulation and reach secondary sites, where they remain largely as single cells. Moreover, ectopic expression of BRMS1 results in a significant decrease in survival of tumor cells within blood stream, increased susceptibility to anoikis and inability to form colonies at secondary organ sites, all events that could be attributed to failure of BRMS1 expressing cells to activate integrins and strongly adhere to ECM components. Here, we show that BRMS1 expression in MDA-MB-231 and MDA-MB-435 cells did not significantly alter expression levels of the integrin monomers tested. However, after short-term (15-30 minutes) plating of cells onto mixed ECM or individual ECM components (collagen I, collagen IV, or fibronectin) under 2D conditions, BRMS1-expressing cells exhibited reduced activation of β1 integrin, focal adhesion kinase (FAK), and scaffolding protein Talin1, as well as a decrease in their localization to focal adhesions. Furthermore, short-term plating of BRMS1-expressing cells on collagens I or IV or fibronectin resulted in marked inhibition of cytoskeletal rearrangement and failure to form cellular adhesion projections, as compared to cells vector-transfected cells. In addition, under 3D conditions, BRMS1-expressing cells remained rounded and failed to reorganize their cytoskeleton even after 24-hour stimulation with serum. Taken together, we believe that these findings demonstrate that BRMS1-expressing breast cancer cells are inherently unable to respond to microenvironment changes, which may explain why they exhibit reduced survival in circulation, increased susceptibility to anoikis, and decreased colonization of secondary sites.

YBK was supported in part by NIH T32 (AR047512-09) and DOD CDMRP BCRP Postdoctoral Fellowship (BC096855)

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1438. doi:10.1158/1538-7445.AM2011-1438
Abstract 144: microRNA-107 regulates PKCepsilon and functions as a tumor suppressor miR in head and neck squamous cell carcinoma
Authors: Datta Jharna , Smith Ashley , Lang James , Islam Mozaffarul , Teknos Theodoros N. , Pan Quintin
Published: June 2012

Head and neck squamous cell carcinoma (HNSCC) is the sixth most prevalent cancer worldwide with about 600,000 new cases diagnosed in the last year. The 5-year survival rate of HNSCC has remained stagnant despite advances in the clinical management of this disease. Understanding the molecular pathways that lead to aggressive HNSCC is crucial to identify new “druggable” targets for anti-cancer drug development. Protein kinase Cepsilon (PKCε) is elevated in HNSCC and regulates cell invasion and motility thorough activation of Rho GTPases. Our laboratory and others provide evidence that PKCε is a transforming oncogene that phosphorylates and modulates a cascade of signal transduction pathways, including Akt, EGFR, Rho GTPases, and Stat3. Thus, targeting PKCε may be an attractive therapeutic approach to dampen multiple hyper-active signaling pathways in concert. At this time, the molecular mechanism of PKCε dysregulation in HNSCC remains to be elucidated. In silico analysis with TargetScan, MiRBase, and miRanda identified numerous putative microRNA (miR) binding sites in the 3’-UTR region of PKCε. We screened a panel of miRs using qPCR and miR-107 was identified to have an inverse association with PKCε in HNSCC cell lines with high endogenous PKCε. Ectopic expression of miR-107 in several HNSCC cell lines significantly reduced PKCε mRNA expression and protein levels. The expression of a luciferase reporter construct containing the 3’-UTR of PKCε was down-regulated by miR-107 and deletion/mutation of the three cognate miR-107 binding sites completely abolished the regulation by miR-107. These observations confirm PKCε as a validated target of miR-107. Ectopic expression of miR-107 in HNSCC cell lines significantly inhibited cell proliferation, DNA replication, clonogenic survival, invasion and migration. Tumor take and tumor growth of HNSCC cells was suppressed by miR-107 in a pre-clinical nude mouse model of HNSCC. Lastly, miR-107 was significantly reduced and showed an inverse expression relationship with PKCε in human primary HNSCC tumors. These results indicate that miR-107 regulates PKCε levels to control the tumorigenicity of HNSCC cells. Taken together, our data substantiate the potential application of miR-107 as a novel anti-cancer therapeutic for HNSCC.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 144. doi:10.1158/1538-7445.AM2011-144