bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 436: Cell surface HSPA8/HSc70 influences invasive tumor cell phenotype
Authors: Watanabe Takafumi , Goodison Steve , Rosser Charles J. , Urquidi Virginia
Published: February 2011

The mechanisms involved in tumor dissemination and metastasis are potential targets for therapeutic intervention. In this study, we used a subtractive immunization approach to generate monoclonal antibodies (mAbs) against proteins preferentially expressed by the highly metastatic human cell line, M4A4. In vitro selection assays selected an antibody that significantly inhibited the migration of this cell line. This antibody was used to immunopurify, and identify the specific target as heat shock 70kDa protein 8 (HSPA8/ HSc70).

Protein expression levels of HSPA8 correlated with different cell clones metastatic ability. Fluorescent immunocytochemistry revealed a cell surface location of HSPA8. The migratory potential of M4A4 cells was similarly reduced by knocking down HSPA8 using siRNA technology, confirming a potential role for this protein in an aggressive tumor cell phenotype. Analysis of gene expression profiles of several clones with reduced HSPA8 expression revealed approximately 200 genes as being regulated by HSPA8, including several that code for putative metastatic factors.

Heat shock proteins are primarily implicated in a cytoprotective role when cells are exposed to stressful stimuli. They are intracellular molecular chaperones but are also found in the surface of embryonic stem cells and a variety of tumor cells.

HSPA8 is moderately induced by heat shock, in response to which it translocates from the cytosol to the nucleus. Immune modulators (like IFN-γ and IL-10) stimulate the release of intracellular HSPA8 from tumors. Extracellular heat shock proteins have recently been shown to mediate a range of powerful effects in inflammatory, neuronal and immune cells through a number of cell surface receptors. The mechanism by which blocking cell surface HSPA8 protein inhibits tumor cell migration and influences the invasive phenotype is currently under investigation.

Note: This abstract was not presented at the AACR 101st Annual Meeting 2010 because the presenter was unable to attend.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 436.
Abstract 4364: Mechanism of promotion effect of diphenylarsenic acid on rat liver carcinogenesis
Authors: Yamada Takanori , Wei Min , Suga Naoto , Wanibuchi Hideki
Published: February 2011

Diphenylarsinic acid (DPAA) is an enviromental degradation of product of diphenylarsine chloride or diphenylarsine cyanide, which were chemical warfare agents produced by Japan during the World War II. DPAA is now considered a dangerous environmental pollution in Kamisu, Japan, where it is suspected of inducing health effect that include articulation disorders, involuntary movements, and sleep disorders. We previously showed that GST-P (Glutathione S-transferase P) positive foci which is precancerous condition increased the number and the area at DPAA 20 ppm but not at below on rat liver carcinogenesis in medium-term bioassay (Ito test), suggesting that DPAA had promotion activities. However, the mechanism of its promotion activities is unclear. The purpose of present study is to clarify the mechanism of DPAA-induced promotion activity in rat liver carcinogenesis. We found that DPAA at 20 ppm but not at below increased significantly in oxidative DNA damage, mRNA expression of CYP1B1, cyclin D1, and c-Myc, and protein level and transcriptional activity of AhR (Arylhydrocarbon receptor) which is implicated in most of the biological responses to the environmental contaminant (e.g. TCDD). Proteome analysis showed that 69 proteins were differentially up or down-regulated in DEN-DPAA 20ppm group compared with DEN alone including 18 proteins of AhR pathway. These results suggested that activity of AhR pathway and oxidative DNA damage on rat liver carcinogenesis involved in promotion activity of DPAA.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 4364.
Abstract 437: A putative role of hypoxia in development of de novo chemoresistance
Authors: Silva Ariosto S. , Gatenby Robert A.
Published: February 2011

In this work we built a computational model that explores the concept of hypoxia induced de novo chemoresistance. We propose that the hypoxic regions of solid tumors not only protect tumor cells from chemotherapy (environmental resistance) but also are the birthplace of de novo multidrug phenotypically chemoresistant cells.

These phenotypically resistant cells would be rare in an untreated tumor due to hypoxia and low external pH (pHe) induced quiescence in the environment where they grow. These cells, however, would be subject to a selective pressure for survival by disruption of apoptotic pathways and overexpression of hypoxia-inducible factors which are known to activate multidrug resistance genes, among other pro-survival mechanisms.

Tumor cells under chronic hypoxic conditions are also subject to higher genetic instability than tumor cells in normoxia, due in part to the decrease in the expression of homologous recombination proteins, what could also increase the rate of evolution towards a multi-drug chemoresistant phenotype.

In the presence of therapy, the sensitive cells (environmentally or phenotypically) are removed from the tumor, reducing hypoxia, normalizing pHe and allowing the phenotypically chemoresistant subpopulation of cells to grow and re-populate the tumor.

This work extends our recent chemoresistance model by adding a representation of HIF-1alpha gene, whose response to hypoxia may change due to mutation from varying thresholds until constant activation or deactivation. The expression of this gene is linked to survival in low pHe, expression of multidrug resistance gene (MDR-1) and glycolysis.

Our simulations show that HIF-1alpha expression is selected towards constitutive activation due to its increase in glycolysis and low pHe resistance, which in turn increase tumor survival and invasion. Multi-drug resistance is also increased in such cells as a consequence of the selection for these two phenotypes.

This work proposes a mechanism for development of chemoresistance in absence of drug which is different from acquired resistance since the selection for this phenotype is not imposed by the drug itself but as side effect of the selection for survival in hypoxia and low pHe.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 437.
Abstract 4379: Involvement of phosphatidylserine externalization and DNA damage in arsenic-induced toxicity to hepatocellular carcinoma (HepG2) cells
Authors: Brown Erika , Yedjou Clement G. , Tchounwou Paul B.
Published: February 2011

Arsenic is a naturally occurring element that is widely distributed in nature, air, water and soil. A well-known toxic and carcinogenic agent, arsenic has been associated with various human malignancies, including skin, lung, liver, kidney and bladder cancers. It has been shown to induce apoptosis in a variety of malignant cell lines, but the precise mechanisms involved in arsenic toxicity and carcinogenicity are not well elucidated. In this study, we used hepatocellular carcinoma (HepG2) cells as a model to determine whether DNA damage and phosphatidylserine externalization are involved in arsenic trioxide (ATO) toxicity. The MTT, single cell gel electrophoresis and annexin-V assays were used to assess cell viability, DNA damage and apoptosis, respectively. The results of the MTT assay demonstrated that ATO significantly reduced the viability of HepG2 cells in a dose-dependent fashion, showing a LD50 value of about 8.5 μg/mL, upon 24 hours of exposure. Data generated from the comet assay showed a significant time and dose-dependent increase in DNA damage, with respect to comet tail-length, tail arm and tail moment, as a result of ATO exposure. In regard to annexin V assay experiment, we observed an increase in annexin V positive cells undergoing early apoptosis in ATO-treated cells compared to the control, upon 2 hr of exposure. However, there was not a detection of annnexin V positive cells in ATO-treated cells compared to the control at 24 hr exposure. Based on the 24 hr cytotoxic effect of ATO to HepG2 cells, further studies are needed to elucidate the apoptotic potential of ATO to HepG2 cells.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 4379.
Abstract 439: Evaluation of hypoxia in a feline model of head and neck squamous cell carcinoma using 64Cu-ATSM positron emission tomography
Authors: McNiel Elizabeth A. , Erfourth Todd M. , Madrill Nicole J. , Agnew Dalen W. , Nelson Nathan C. , Ballegeer Elizabeth A. , Berger Kevin L.
Published: February 2011

Tumor hypoxia substantially impacts the prognosis of cancer patients by impairing the response to therapy and by promoting the acquisition of a malignant cellular phenotype. A variety human tumors exhibit hypoxia including head and neck squamous cell carcinoma (HNSCC) where it is considered a barrier to successful management of these patients. In the feline, HNSCC is a common and aggressive malignancy that shares morphologic, clinical and molecular features with human HNSCC. Therefore, feline HNSCC may serve as an informative model. To date, there are no data concerning the occurrence of hypoxia in feline HNSCC. We hypothesized that like its human counter part, feline HNSCC would demonstrate regions of intratumoral hypoxia and that hypoxia would be a feature of malignant rather than benign oral tumors. To test this hypothesis, cats with spontaneously occurring oral tumors (N=7) were administered 2 mCi 64Cu- diacetyl-bis(N4-methylthiosemicarbazone) (ATSM) IV 20 minutes prior to PET-CT scan (Discovery ST, GE Healthcare). Histologically, 4 cats had invasive squamous cell carcinoma, 1 had osteosarcoma and 2 had inflammatory lesions (1 polyp and 1 granuloma). All four squamous cell carcinomas and both inflammatory lesions demonstrated strong diffuse uptake of 64Cu within the tumor. Two cats with metastases to regional lymph nodes also demonstrated significant 64Cu uptake. Tumor hypoxia was confirmed by fluorescent lifetime probe measurements (Oxylab pO2), Oxford Optronix) in 4 cats and pimonidazole (HypoxyporbeTM-1, Hypoxyprobe Inc) uptake in biopsy samples in 4 cats. These data indicate that HNSCC in the cat exhibits significant, diffuse hypoxia. Hypoxia was also significant in inflammatory lesions and thus was not a marker of malignancy, but could indicate that inflammatory disease may provide a selective microenvironement to promote tumorigenesis in the cat. The feline model may provide an important tool for studying clinical methods to modulate hypoxia and to study the role of hypoxia on oral carcinogenesis. We are currently evaluating the effect of vascular modulating agents on feline HNSCC and intratumoral hypoxia as a means to optimize this therapy for combination with irradiation.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 439.
Abstract 4392: Oxidative damage to placental DNA, air pollution, genetic polymorphisms and pregnancy outcomes
Authors: Rossner Pavel , Tabashidze Nana , Dostal Miroslav , Novakova Zuzana , Chvatalova Irena , Spatova Milada , Srám Radim J.
Published: February 2011

Oxidative stress to placenta DNA may result in negative pregnancy outcomes, including intrauterine growth retardation (IUGR) and low birth weight (LBW). The aim of our study was to investigate the association between the levels of 8-oxodeoxuanosine (8-oxodG), a marker of oxidative DNA damage, in placenta DNA, exposure to particulate matter <2.5 µm (PM2.5) and benzo[a]pyrene (B[a]P) during pregnancy, genetic polymorphisms in 97 genes and pregnancy outcomes in a group of 891 newborns born between the years 1994 and 1999 in the Czech Republic in two districts with different levels of air pollution. We observed a borderline difference in oxidative stress levels between the IUGR and non-IUGR group (median 8-oxodG/105 dG (range): 2.03 (0.29-6.17) and 1.74 (0.20-6.50), p=0.055, for the IUGR and non-IUGR group, respectively) and higher oxidative stress in the LBW newborns (median 8-oxodG/105 dG (range): 2.25 (0.27-6.25) and 1.75 (0.20-6.50), p<0.05, for the LBW and non-LBW group, respectively). Univariate regression analysis revealed single nucleotide polymorphisms (SNPs) in 12 genes (ADH1B, ALDH2, BCL6, CCL2, CTLA4, CXCL10, CYP1A2, CYP2D6, GATA3, IL13, MGMT, XPC) to be associated with 8-oxodG levels; IUGR was associated with SNPs in 6 genes (AHR, C5, CCL24, CTLA4, TLR4, XRCC3), while LBW with SNPs in 18 genes (ADH1C, CCL7, CCL8, CCL18, CYP1A1, ERCC3, HMOX1, IL10, LIG1, LTA, MBL2, STAT4, TOLLIP, TLR2, XPC, TP53, XRCC1, XRCC3). 8-oxodG levels were increased by exposure to PM2.5 in the first four moths of pregnancy; exposure to B[a]P had no effect. Multivariate-adjusted logistic regression revealed that newborns with above-median levels of 8-oxodG (>1.80 8-oxodG/105 dG) had 64% higher probability of IUGR (OR (95% CI): 1.64 (1.12-2.42), p<0.05) than newborns with below-median levels of oxidative DNA damage. Genetic polymorphisms in ADH1B, C5 and TLR4, as well as body mass index and the length of education of the mother also significantly affected the risk of IUGR. Oxidative DNA damage was not confirmed by multivariate-adjusted logistic regression to be a risk factor of LBW. Variables affecting LBW include genetic polymorphisms in CCL7, HMOX1 and STAT4, gender, mother's smoking and the length of gestation. In summary, our results suggest that oxidative DNA damage increases the risk of IUGR; exposure to air pollution during pregnancy is not a significant independent factor affecting 8-oxodG-related IUGR. Supported by the Czech Ministry of the Environment (SP/1b3/50/07).

Note: This abstract was not presented at the AACR 101st Annual Meeting 2010 because the presenter was unable to attend.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 4392.
Abstract 4402: Fsn0503: A novel therapeutic antibody for the treatment of colorectal cancer
Authors: Gormley Julie A. , Olwill Shane A. , Hegarty Shauna M. , Scott Christopher J. , Burden Roberta E. , Johnston James A. , Kay Elaine W.
Published: February 2011

Local invasion and metastasis is the primary cause of death in many cancers. Extracellular matrix degradation by proteolytic enzymes facilitates tumour invasion into the surrounding tissue, eventually leading to metastatic spread of the disease. Cathepsin S (CTSS) is a lysosomal cysteine protease, which has been shown to play a role in promoting tumour invasion and angiogenesis. CTSS has been found to be overexpressed and secreted in a number of cancer tissues including astrocytoma and prostate. We have developed Fsn0503, a novel antibody that targets and inhibits the extracellular activity of CTSS. Fsn0503 specifically binds to and inhibits the activity of CTSS. It significantly attenuates invasion of a range of colorectal cancer cell (CRC) lines in vitro (e.g. HCT116 64% at 200nM). Fsn0503 also demonstrates anti-angiogenic effects; it significantly reduces microtubule formation by HUVEC cells in vitro and vessel outgrowth in the (ex vivo) rat aortic ring model. Fsn0503 also impairs tumour growth and vascularisaton in the HCT116 colorectal xenograft model and reduced metastatic burden in a 3LL metastatic model, with no signs of toxicity. As these data suggest a role for CTSS in CRC progression, we probed its expression pattern in a large-scale immunohistochemical study spanning five cohorts of patients (n=600). Greater than 90% of tumours show intense expression of CTSS compared with weak or undetectable expression in the normal colonic epithelium. Increased CTSS expression in lymph node metastatic tissue compared to normal tissue was also observed. These compelling results signify an important role for CTSS in malignant progression of CRC and accompanying metastases. Demonstration of in vivo efficacy highlights the therapeutic potential of targeting CTSS with an antibody. Overall, our data indicate that Fsn0503 is an exciting experimental therapeutic which has great clinical potential

Note: This abstract was not presented at the AACR 101st Annual Meeting 2010 because the presenter was unable to attend.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 4402.
Abstract 4406: A monoclonal antibody targeting PAUF inhibits metastasis of pancreatic cancer
Authors: Lee Yangsoon , Kim Su Jin , Min Hye Jin , Yu Kyung Sook , Park Eun Hye , Koh Sang Seok
Published: February 2011

Pancreatic cancer is one of the deadliest human tumors and, due to lack of effective therapeutic agents and diagnostic tools, has a poor prognosis with approximately a five-year survival rate of less than 5%. This disease is characterized by early metastatic spread but the process of tumor cell dissemination is largely unknown. Recently, we have shown that a novel soluble protein named PAUF (Pancreatic Adenocarcinoma Up-regulated Factor) plays an important role in the metastasis and progression of the disease. The expression of CXCR4 is induced by PAUF, implicating a role of PAUF in the organ specific metastasis of pancreatic cancer. The tumorigenic and metastatic activity of PAUF suggests that PAUF could be a target for pancreatic cancer immunotherapy. To examine the therapeutic potential of PAUF, a human monoclonal antibody against PAUF (8F3) has been generated. The 8F3 antibody exerted inhibition of migration, invasion, adhesion and proliferation of pancreatic cancer cells in vitro. In combination with gemcitabine, 8F3 showed additive effect on reduction of cell growth. In orthotopically xenografted mouse model, these anti-tumor activities of 8F3 converted to growth retardation and repression of metastasis. The level of PAUF in tumor and serum from 8F3 treated mouse was lower than that of control mouse. The immunohistochemical analysis revealed that the treatment of 8F3 inhibited the proliferation and CXCR4 expression in both primary and metastasized tumors. The 8F3 antibody also alters intracellular signaling which was induced by PAUF. We will also discuss about the effect of 8F3 in tumor microenvironment, especially recruitment of immune cells. Collectively, these findings indicate that PAUF has a therapeutic potential for treatment of human pancreatic cancer and the 8F3 antibody can be developed for therapeutic agent for this disease.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 4406.
Abstract 4410: Apoptosis in Ovarian Cancer Cells Induced by Polyclonal Antibodies to Secreted Frizzle-related Protein 2
Authors: Rossi Emma C. , Siamakpour-Reihani Sharerah , Ketelsen David , Van Le Linda , Patterson Cam , Klauber-DeMore Nancy
Published: February 2011

Objectives: We have previously discovered a novel angiogenesis factor, secreted frizzle-related protein 2 (SFRP2), that is strongly expressed in many human tumors including ovarian carcinoma. SFRP2 protects against endothelial cell apoptosis, and induces endothelial tube formation and migration. We hypothesize that in addition to its paracrine role in stimulating angiogenesis, SFRP2 also has a direct effect in tumor cells, and therefore blocking SFRP2 will induce ovarian cancer apoptosis.

Methods: Protein expression of SFRP2 in ovarian cancer cells: SKOV-3 and OVCA −3 ovarian cancer cells were cultured in McCoy's medium with 10% bovine serum albumin. Whole cell protein lysates were obtained and Western blot analysis was performed probing for SFRP2. Apoptosis assay: SKOV3 cells were plated in 96 well plates and allowed to attach overnight. Rabbit polyclonal antibody to SFRP2 (SFRP2 Ab) was run through a column with a saline buffer to remove the sodium azide preservative. Cells were treated with antibody in 1:10, 1:100, and 1:1000 concentrations. McCoy's culture medium with 1% saline was used as a negative control. Cells were incubated at 37°C for 48 hours. Apoptosis was measured by the activity of cleaved caspase-3 by using a caspase-specific fluorogenic substrate. Statistical analysis was performed with a two-tailed student's t-test.

Results: SKOV-3 and OVCA-3 ovarian cancer cells strongly express SFRP2 on Western Blot analysis. When SKOV-3 cells were treated with polyclonal antibody to SFRP2 (1:10) there was a 47% increase in apoptosis as compared with negative controls (control = 1509 RFU ± 50, SFRP2 Ab =2221 RFU ± 39, n=4 for both groups, p<0.0001).

Conclusions: SFRP2 is a protein endogenously expressed by ovarian carcinoma. Blocking SFRP2 with a polyclonal antibody induces apoptosis in SKOV-3 ovarian cancer cell line, suggesting that this protein may be a potential target in the treatment of ovarian cancers.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 4410.
Abstract 442: Down-regulation of MET/RON receptor tyrosine kinases in colon cancer cells under chronic hypoxia as a mechanism for resistance towards targeted therapy
Authors: Guin Sunny , Ma Qi , Padhye Snehal , Zhang Hong-Ying , Wang Ming-Hai
Published: February 2011

Hypoxia is a pathogenic factor observed in solid tumors, which plays a critical role in tumor malignancy and drug resistance. The MET and RON receptor tyrosine kinases belong to a unique proto-oncogene family and contribute to tumorigenic progression and malignant phenotypes in various epithelial cancers. To address their pathogenic significance under chronic hypoxic condition (1% O2, 5% CO2 for 5 days), functional analysis of MET and RON were conducted using colon cancer HCT116 and HT29 cells as models. Contrary to previous reports, we consistently observed that levels of MET and RON were significantly decreased over a period of 5 days under chronic hypoxic condition as documented by Western blot and cell-surface fluorescent analysis. The reduction was also accompanied with decreased in both spontaneous and ligand (HGF/MSP)-induced tyrosine phosphorylation manners, which affected the downstream signaling cascades. Moreover, we observed that hypoxia-induced HIF-1α expression (known as a positive regulator for both receptors) is unable to sustain MET or RON expression, suggesting that the receptor down-regulation is mediated through a HIF-1α-independent mechanism. RT-PCR analysis revealed that diminished MET and RON expression occurs at the mRNA transcription level. However, increase in protein degradation also contributed to the observed reduction. Functional studies further demonstrated that chronic hypoxia facilitates colon cancer cells to develop a unique pathogenic phenotype. This phenotype was featured by reduced cell migration, decreased cell proliferation, and lack of S phase in cell cycle profile. Tumor cells were also insensitive in response towards HGF or MSP-induced cell movement and replication. These cancer cells were resistant to cytotoxic effects induced by MET-RON duel small molecule inhibitors such as PHA665752 and compound I. As shown by cytotoxicity assay, the IC50 values of these inhibitors in cell survival were significantly increased in cancer cells under chronic hypoxic treatment compared to normoxic cells. In conclusion, our results demonstrate that under chronic hypoxia colon cancer cells developed a pathogenic phenotype characterized by diminished expression of MET and RON. Such a change contributes to the insensitivity of tumor cells towards cytotoxic activities of specifically targeted drugs. Thus, diminished expression of MET and RON under chronic hypoxia is a potential mechanism that affects the effectiveness of targeted therapy in the treatment colon cancer.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 442.
Abstract 4423: Novel therapeutic potential in targeting the microtubules by nanoparticle albumin-bound paclitaxel in hepatocellular carcinoma
Authors: Zhou Qian , Ching Arthur K-K , Leung Wilson K-C , Szeto Carol , Ho Shuk-Mei , Holmes Chris C. , Yuan Yun-fei , Lai Paul B-S , Yeo Winnie , Wong Nathalie
Published: February 2011

Hepatocellular carcinoma (HCC) shows low responses to most conventional chemotherapies. To facilitate target identifications for novel therapeutic developments, we deployed gene expression profiling on 43 paired HCC tumors and adjacent non-tumoral liver. Coupled with ontology analysis, the major functional process suggested in the malignant transformation of HCC was microtubule-related cellular assembly. We further examined the potential use of microtubule targeting Taxane drugs, including Paclitaxel and Docetaxel, and compared findings to the results obtained from Doxorubicin, a common chemotherapeutic agent used in the treatment of a number of neoplasms. Recent studies showed that drug delivery by nanoparticles have enhanced efficacy with reduced side effects. In this regard, the nanoparticle albumin-bound (nab)-Paclitaxel was also examined. In a panel of HCC cell lines studied, a high sensitivity towards Taxane drugs was generally found, although the effect from nab-Paclitaxel was most profound. The nab-Paclitaxel showed an effective IC50 dose at 15-fold lower than Paclitaxel alone or the derivative analogue Docetaxel, and approx.450-fold less compared to Doxorubicin. Flow cytometric analysis confirmed a cell cycle blockade at the G2/M phase and increased apoptosis following treatment with nab-Paclitaxel. In-vivo animal study also showed that nab-Paclitaxel readily inhibited xenograft growth with less toxicity compared to other anti-microtubule drugs and Doxorubicin. Silencing of a major microtubule regulatory gene STMN1 suggested a distinct synergistic effect in the combined treatment with nab-Paclitaxel. Our findings in this study would suggest the microtubule organizations to represent a promising target for treatment developments in HCC.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 4423.
Abstract 4425: Oral efficacy and preclinical ADME evaluation of CKD-516, a novel tubulin polymerization inhibitor
Authors: Kim Soo Jin , Kim Se-Mi , Choi Jae-Hoon , Lee Do Hyung , Lee Dong Wook , Park Gyu-Tae , Lim In-Taek , Jeon Deok-Jin , Lee Seonwoo , Kim Dal-Hyun , Lee Kyung Joo , Lee Sungsook , Hong Chung Il
Published: February 2011

CKD-516 is a potent anticancer agent that inhibits microtubule assembly and disrupts tumor vasculature (VDA). CKD-516 is an amino acid prodrug of S516 releasing S516 in vivo. Previously we reported the discovery and its antitumor efficacy of CKD-516 as well as various in vitro studies (Abstract 5561, 2009 AACR). As a continuation of the investigation, a detailed ADME evaluation of CKD-516 in both rats and dogs and its potential as an oral agent is described in this report.

Following intravenous administration to rats and dogs, CKD-516 rapidly became the active metabolite S516 in plasma and the half-lives of S516 were 1.5 hrs in rats, and 8 hrs in dogs. Protein binding was high with an unbound fraction less than or equal to 20% in all species tested. In distribution studies in rats dosed intravenously, S516 was mainly distributed in thymus, lung and stomach and had a short half-life less than 2 hrs in all tissues tested. In rats, the excretion of CKD-516 in urine, bile and feces amounted to 0.22%, 8.22% and 4.92%, respectively.

S516 was found to have comparable metabolic stabilities both in dog and human liver microsomes where there was no difference between male and female microsomes. However, the rate of metabolism in rats from male and female liver microsomes were markedly different.

In general, S516 is expected to have low drug-drug interaction with IC50 values of >10 μM against most CYP450 enzymes but had a moderate inhibition against CYP450 1A2 and 2C8.

The intestinal absorption of CKD-516 was predicted to be moderate to high as the apparent permeabilities (×106 cm/sec) of CKD-516 and its active metabolite S516 in Caco-2 permeability assay were 15.1 and 35.4, respectively. Thus, CKD-516 was found to have an acceptable oral bioavailability in rats, supporting its potential efficacy as an oral agent.

In vivo antitumor experiments were performed in the HCT116 human tumor xenograft model. When the established tumor reached the size of 150 mm3, CKD-516 was administered to mice orally. Groups of animals were received CKD-516 with doses of 10 mg/kg or 20 mg/kg (Q4d × 5). The treated group showed a tumor growth suppression (IR = 50∼60%). Drug related toxicity and body weight decrease were not detected at doses tested.

In summary, a complete ADME characterization of CKD-516, a novel tubulin polymerization inhibitor and VDA, both in vitro and in vivo was described. Moreover, CKD-516 was found to have a good potential as an oral agent.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 4425.
Abstract 4431: A novel derivative of the Cdk inhibitor roscovitine that induces apoptosis in CLL and overcomes stromal cell-mediated protection
Authors: Chen Rong , Chen Yuling , Green Simon R. , Wierda William G. , Plunkett William
Published: February 2011

Cmpd 5 is a derivative of R-roscovitine (CYC-202, seliciclib) with increased potency that selectively inhibits Cdk2, Cdk5 and Cdk9. In chronic lymphocytic leukemia (CLL) a disease that is addicted to the over-expression of anti-apoptotic proteins for survival, inhibition of Cdk9 by Cmpd 5 reduced phosphorylation of the C-terminal domain of RNA polymerase II and blocked transcription. These actions depleted the intrinsically short-lived anti-apoptotic protein Mcl-1, and induced apoptosis in CLL cells in vitro. Cmpd 5 was about 30 times more potent than its parent compound R-roscovitine with an IC50 of 0.86 µM after a 24-hr incubation. Although cell death was initiated after a 4-hr incubation in a time course study of Cmpd 5-induced apoptosis, the maximum cell death was not reached until 10-12 hr. In addition, it was known that co-culture of CLL cells with the marrow and lymphoid stromal cells may be responsible for resistance to fludarabine therapy. We evaluated Cmpd 5 in overcoming such stromal cell-mediated protection. Cmpd 5 killed the CLL cells similarly in the presence or absence of the human stromal cell line StromaNKtert without toxicity to the stromal cells, whereas the stromal cells clearly protected the CLL cells from the toxicity of fludarabine. Since Mcl-1 is the major target of Cmpd 5 in CLL, and the action of Cmpd 5 relies on the intrinsically rapid turn-over rate of Mcl-1, we compared the protein levels and the half-life of Mcl-1 in CLL cells in the presence or absence of the stromal cell layer. After an overnight incubation of CLL cells with the StromaNKtert cells, there was a 3-4 fold induction of Mcl-1 transcript and protein. However, there was no difference in the Cmpd 5-induced decay rate of either the Mcl-1 mRNA or protein, indicating that stromal cells did not alter the stability of Mcl-1. Therefore, the elevated Mcl-1 level likely indicated increased biosynthesis, rather than enhanced stability. Thus, the activation of the survival pathways and induction of the biosynthesis of Mcl-1 by the stromal cells may protect CLL cells from fludarabine-induced apoptosis but loss of the short-lived anti-apoptotic proteins was not affected, explaining the lack of stromal cell protection for CLL cells from Cmpd 5. Similar time-dependence of cell death induction as well as stromal cell response was also observed with other inhibitors of transcription including flavopiridol, R-roscovitine and Actinomycin D, implying a class effect. Taken together, our data suggested that Cmpd 5 is a promising candidate for clinical development for CLL.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 4431.
Abstract 4446: Targeted proteasome inhibition by Velcade induces apoptosis in human mesothelioma and breast cancer cell lines
Authors: Wang Ying , Rishi Arun K. , Puliappadamba Vineshkumar T. , Sharma Sunita , Yang Huanjie , Tarca Adi , Dou Q. Ping , Lonardo Fulvio , Ruckdeschel John C. , Pass Harvey I. , Wali Anil
Published: February 2011

Thoracic malignancies and human breast cancers (HBC) continue to be aggressive solid tumors that are poor responders to the existing chemotherapeutic approaches. Malignant Pleural Mesothelioma (MPM) is an asbestos-related tumor of the thoracic pleura that lacks effective treatment options. Altered ubiquitin proteasome pathway is frequently encountered in many malignancies including HBC and MPM and thus serves as an important target for therapeutic intervention strategies. Although proteasome inhibitor Velcade (Bortezomib) has been under clinical investigation for a number of cancers, limited preclinical studies with this agent have thus far been conducted in HBC and MPM malignancies. Here, we studied the role of Velcade mediated changes in cellular, morphological, and molecular patterns in five MPM (H2595, H2373, H2452, H2461, and H2714) and two HBC (MDA MB-468, SKBR-3) cell lines. Our data revealed significant reduction in cell growth properties that were dose and time dependent. Velcade treatment resulted in G2M phase arrest, increased expression of cyclin-dependent kinase inhibitor p21 and pro-apoptotic protein Bax. Pretreatment of MPM cells with Velcade showed synergistic effect with cisplatin combination regimens. High-throughput gene expression profiling among Velcade treated and untreated MPM cells resulted in identification of novel transducers of apoptosis such as CARP-1, XAF1, and Troy proteins. Thus, Velcade targets cell cycle and apoptosis signaling to suppress MPM and HBC growth in part by activating novel transducers of apoptosis. This pilot study has paved way for further in-depth analysis of the downstream target molecules associated with presensitization of mesothelioma cells in finding effective therapeutic treatment options for both mesothelioma and recalcitrant breast cancers.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 4446.
Abstract 4451: The effects of anthocyanins from the fruit of Vitis coignetiae Pulliat on NF-κB and NF-κB-regulated gene expressions in human lung cancer cells
Authors: Lee Won Sup , Kim Min Jeong , Yun Jeong Won , Lu Jing Nan , Kang Myung Hee , Kim Hun Gu , Kim Dong Chul , Kim Hae Gyeong , Lee Yun Koung , Jeong Jae-Hoon , Choi Yung Hyun , Kim GonSup , Ryu Chung Ho , Park Ok Jin , Shin Sung Chul
Published: February 2011

Vitis coignetiae Pulliat (Meoru in Korea) has been used as a remedy for inflammatory diseases and various cancers. We isolated anthocyanins from Meoru. We previously suggested that anthocyanins from fruits of Vitis coignetiae Pulliat (Meoru in Korea) should have anti-invasive effects through suppression of NF-κB activation. Here, we investigated their effects on NF-κB-regulated gene products and cellular responses in human lung cancer cells. The anthocyanins inhibited NF-κB activation in a dose-dependent manner. TNF-α augmented proliferation, migration and invasion of A549 cells. The anthocyanins inhibited the augmented proliferation, migration and invasion of the cancer cells by TNF-α. We also found that the anthocyanins suppressed NF-κB-regulated proteins involved in caner proliferation, metastasis and anti-apoptosis. The anthocyanins inhibit NF-κB activity by inhibiting IκBα phosphorylation. Taken together, this study suggested that the anthocyanins isolated from fruits of Vitis coignetiae Pulliat inhibit the NF-κB activation and downstream proteins, which may be a factor in their anticancer activities of fruit of Vitis coignetiae Pulliat.

Keywords: anthocyanins, Vitis coignetiae Pulliat, NF-κB, cancer

* This study was supported by a grant from the National R&D Program for Cancer Control, Ministry for Health, Welfare and Family affairs, Republic of Korea (0820050)

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 4451.
Abstract 4456: Molecular events required for the induction of lethal iron deprivation in malignant hematopoietic cells via an antibody-avidin fusion protein specific for human transferrin receptor 1
Authors: Rodríguez José A. , López-Valdes Héctor E. , Helguera Gustavo F. , So Sokuntheavy , Luria-Pérez Rosendo , Daniels Tracy R. , Charles Andrew C. , Penichet Manuel L.
Published: February 2011

Iron is an essential nutrient for cell growth and division. The transferrin receptor 1 (TfR1 or CD71) is a major gateway for iron import, and as such is expressed on a variety of cells; it is over-expressed in a number of tumors including hematopoietic malignancies. We have previously shown that an antibody-avidin fusion protein (ch128.1Av) specific for TfR1 is toxic to cancer cells, capable of inducing lethal iron deprivation in some malignant B-cells such as IM-9, but not in others such as U266. Importantly, ch128.1Av induces iron deprivation without directly preventing the binding of transferrin (Tf) to TfR1. In an attempt to identify the molecular events behind the iron deprivation induced by ch128.1Av, we have found that like Tf, internalization of ch128.1Av bound to TfR1 is clathrin, dynamin, and temperature dependent. Additionally, recycling of TfR1-bound ch128.1Av at short timescales (30min) is also similar to that of Tf and does not significantly alter the rate of Tf uptake. Long-term incubation (>6h) of IM-9 cells with ch128.1Av precludes their uptake of Tf and induces degradation of TfR1. This is not the case with U266 cells, in which Tf uptake remains unaffected and degradation of TfR1 is negligible in the presence of ch128.1Av. Clustering of cell surface TfR1 by ch128.1Av, given its multivalent nature, was previously thought to cause degradation of the receptor in sensitive cells such as IM-9. We now show that clustering of TfR1 occurs both in cells that are sensitive and resistant to treatment with the antibody (IM-9 and U266), indicating that clustering of TfR1 induced by ch128.1Av is not sufficient to induce receptor degradation and subsequent iron deprivation. Instead, resistance to treatment with ch128.1Av may be attributed to elements downstream of receptor binding/clustering; possibly related to those involved with TfR1 recycling and degradation. Further studies are needed to identify these resistance factors and potentially enhance the efficacy of ch128.1Av as well as other antibodies and/or small molecules that similarly target TfR1 for the treatment of hematologic malignancies.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 4456.
Abstract 4472: NVP-BKM120, a pan class I PI3K inhibitor impairs microvascular permeability and tumor growth as detected by DCE-MRI and IFP measurements via radio-telemetry: Comparison with NVP-BEZ235
Authors: Schnell Christian R. , Arnal Samuel , Becquet Mike , Allegrini Peter , Voliva Charles , Cozens Robert , Garcia-Echeverria Carlos , Maira Sauveur Michel
Published: February 2011

Tumor blood vessels are distinctly abnormal in structure and function. When compared to normal vessels, they are enlarged and tortuous and leaky, poorly covered by pericytes and with a defective basement membrane. VEGF is a prominent cytokine responsible for the hyperpermeable state of tumor microvasculature to plasma macromolecules. The phosphatidylinositol 3-kinase (PI3K)-Akt signaling pathway functions downstream of VEGF and can activate the production of the free radical gas nitric oxide (NO) through the enzyme endothelial NO synthase (eNOS), a key player for the in vivo biological activity of VEGF.

In the present study, we investigated the effect of NVP-BKM120, a novel, synthetic low molecular mass compound, which potently inhibits class I PI3K activity, on vascular leakage in tumors and its impact on tumor progression in an orthotopic breast cancer model (BN472) in syngeneic rats. Effects on the vasculature were investigated in normal and tumor tissues with a variety of technologies: dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI), tumor interstitial fluid pressure (IFP) measurements in conscious animals via radio-telemetry and a modified Miles assay, representing non invasive, minimally invasive and invasive methods, respectively. Tumor histology and western blots were used to confirm pathway inhibition.

For comparison, the effect of NVP-BEZ235, a potent pan class I PI3K and mTOR activity inhibitor, was assessed head-to-head in the same experiments.

BKM120 induced significant decreases in VEGF-induced vascular leakage in normal and tumor tissues. These effects were similar to those obtained following BEZ235 treatment. Western blot of total ear lysates from treated mice clearly demonstrated pathway inhibition. The inhibition of vessel permeability observed with BEZ235 and BKM120 correlated with their respective anti-tumor activities, IFP change and Ktrans (vascular permeability transfer constant measured by DCE-MRI) decrease.

In conclusion, our data demonstrate that in BN472 tumors, BKM120 significantly decreases tumor microvascular leakage similar to BEZ235 at equipotent antitumor dose. Changes in Ktrans may be a useful independent clinical surrogate biomarker for NVP-BKM120 efficacy.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 4472.
Abstract 4513: IND-enabling studies for CEQ508 targeting β-catenin of GI polyps: First oral RNAi drug
Authors: Bodyak Natalya , Borrelli Alex , Fruehauf Johannes H. , Harborth Jens , Laroux F. Stephen , Vaze Moru , Grillot-Courvalin Catherine , Silva Alison D.
Published: February 2011

Targeted delivery remains one of the biggest challenges in the development of RNAi-based therapeutics. Cequent has developed a proprietary delivery technique for RNA interference, transkingdom RNAi (tkRNAi), in which non-pathogenic bacteria are engineered to invade specific target cells, produce and release short hairpin RNA (shRNA). We have previously shown tkRNAi to be successful in cell culture assays, in a mouse model for human colon cancer (APCmin), and in non-human primates (cynomolgus monkeys), by suppressing the oncogene, β-catenin. β-catenin is the key oncogene implicated in Colorectal Cancer (CRC) and Familial Adenomatous Polyposis (FAP); the latter being an orphan hereditary disease resulting in the formation of hundreds of polyps in the gastrointestinal tract and ultimately leads to the development of colon cancer without surgical intervention. No pharmaceutical treatment is available for patients with FAP. The non-human primate studies designed to evaluate on-target toxicities were conducted with a precursor (CEQ501) to our clinical candidate, CEQ508. Following optimization, which most importantly included platform engineering to improve hairpin production and processing, we conducted a large GLP mouse bridging toxicity study comparing off-target effects of CEQ508 and CEQ501. No CEQ508 or CEQ501-related adverse responses were identified in the following study parameters analyzed: clinical observations, body weights, serum chemistry, hematology, cytokines, gross or histopathology. As no test article-related changes were identified under the conditions of this study at the highest dose evaluated, the No Observed Effect Level (NOEL) for daily oral administration of either CEQ508 or CEQ501 was 5×109 cfu/day, or 2×1011 cfu/kg/day. (CEQ501 in non-human primates showed a similar safety profile with the No Observed Adverse Effect Level (NOAEL) determined to be 1×1012 cfu/day, or 2×1011 cfu/kg/day). Together with multiple internally conducted pharmacology and pharmacokinetic experiments, Cequent used this data in the nonclinical section of an IND filed in late 2009. In addition to presenting detailed in vivo data from our filing, an update on further development will be presented on CEQ508 for the proposed daily dosing of FAP patients with this oral tkRNAi therapeutic targeting β-catenin.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 4513.
Abstract 4528: Small molecules inhibitory for MDMX expression activate p53 and induce apoptosis
Authors: Wang Hongbo , Ma Xujun , Ren Shumei , Yan Chunhong
Published: February 2011

P53 inactivation caused by aberrant expression of its major regulators(e.g, MDM2 and MDMX) contributes to 50% of human cancers. Recent studies have demonstrated that restoration of p53 activity by counteracting p53 repression is a promising anti-cancer strategy. Although agents(e.g., Nutlin-3a) disrupting the MDM2-p53 interaction can inhibit tumor growth, they are less effective in cancer cells with high MDMX expression levels. MDMX binds to p53 and serves as a major p53 antagonist by mainly repressing its transcriptional activity. Here we reported the identification of two samll molecules inhibitory for MDMX expression through high-throughput screening. Treatments of MCF-7 cells with these MDMX inhibitors dramatically increased the stability of p53, leading to elevated expression of proapoptotic genes(e.g., PUMA, Bax, and PIG3). These results argue for a recent notion that MDMX is a major regulator of the p53 stability. While they exerted limited effects on cell cycle progression, this new class of small-molecule p53 activitors induced MCF7 cells to undergo apoptosis. However, the MDMX inhibitors only modestly enhanced p53 activition induced by Nutlin-3a. We conclue that small molecules targeting MDMX expression would be of therapeutic benefits and be useful in dissecting the p53 network through chemical biological approaches.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 4528.