bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 2892: Enhancing anti cancer activity of PI103, a dual PI3K/mTOR inhibitor, by designing a self assembled Nanoformulation
Authors: Roy Bhaskar , Sengupta Poulomi , Soni Shivani , Papa Anne Laure , Kopparam Jawahar , Sarangi Sasmit , Pandey Ambarish , Basu Sudipta , Sengupta Shiladitya
Published: August 2012

The phosphoinositide 3-kinase (PI3K)/ mammalian target of rapamycin (mTOR) pathway plays a pivotal role in the growth and survival of various cancers. Small molecule inhibitors targeting PI3K/AKT/mTOR pathway (eg. Wortmannin, LY294002, PI-103, PI828) are promising anti cancer agents. Major drawbacks of these drugs are their poor water solubility and off-target toxicity. Nanoscale drug delivery systems have been harnessed as drug carriers to target tumours through enhanced permeation and retention effect. In this study, we developed a nanoformulation of PI103, a potent dual PI3K/mTOR inhibitor, to improve delivery and reduce side effects. PI103 was encapsulated in a homogeneous self-assembled mixture of phosphatidylcholine and cholesterol. DSPE-PEG protective shell was introduced to increase its circulation time. Thin-film-hydration technique followed by extrusion through 200 nm porous membranes developed nanoparticles of 110-150 nm size with 0.15-0.20 mM drug loading. Release kinetics study confirmed the stability of this formulation in PBS for several days as well as a sustained release property in in-vitro Cell Lysate system. In-vitro cell proliferation assay demonstrated improved cytotoxicity of nanoformulated PI103 in murine breast cancer cell line 4T1 and K-ras upregulated and PTEN suppressed ovarian cancer model cells. Fluorescent Activated Cell Sorting (FACS) analysis with FITC tagged Annexin-V, an early apoptosis marker, showed increased apoptosis with the nanoformulation than the free drug. Western blot analysis expressed more potent inhibition of PI3 kinase/Akt pathway by the nanoformulated PI103. These results indicate that nanoformulation can enhance the potential of PI103.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 2892. doi:1538-7445.AM2012-2892
Abstract 3011: Correlation of PERK activation with increased GRP78-binding in UVB-irradiated HaCaT cells
Authors: Tong Lingying , Wu Shiyong
Published: August 2012

Ultraviolet (UV) light has been shown to be a potential human carcinogen, and it is widely accepted that UV exposure can impact protein expression via both transcriptional and translational regulation. PERK is one of the eIF2α kinases that is activated and inhibits protein synthesis upon UV irradiation. However, the mechanism for UV-induced PERK activation is not fully elucidated. In this study, we evaluated the role of GRP78/BiP, an inhibitory PERK-binding protein, in the regulation of PERK activity in UVB irradiated cells. Our data showed that while PERK expression was reduced in both human keratinocytes (HaCaT) and mouse embryonic fibroblasts (MEF) cells, GRP78/BiP expression remained steady in HaCaT and slightly increased in MEF cells after UVB irradiation. Our data also showed that the Tyr phosphorylation of PERK, an indication of activation, was increased after UVB irradiation, which confirmed the role of PERK in UV-induced translational regulation. Unexpectedly, a co-immunoprecipitation analysis indicated PERK activation was accompanied with an increase in PERK-bound GRP78/BiP in the irradiated HaCaT cells. Based on these results, we propose that UV-induced PERK activation might be GRP78/BiP-independent, and its activation pathway in HaCaT cells may be unique from other cell lines.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 3011. doi:1538-7445.AM2012-3011
Abstract 3012: The mechanism of UV-induced and prohibitin-mediated apoptosis
Authors: Wu Qiong , Wu Shiyong
Published: August 2012

Ultraviolet B (UVB) light is a potential environmental carcinogen, which has been shown to cause various skin cancers. Normally, UV-damaged cells are eliminated by the self-protective apoptosis response. UVB-induced apoptosis can be regulated by modification of major lipid raft components, such as cholesterol and ceramide. Upon UVB irradiation, an alteration of lipid raft composition leads to the recruitment/activation of raft-associated proteins and initiates downstream apoptotic signaling pathways. To identify potential regulators of UVB-induced apoptosis, we used 2D gel electrophoresis to identify the raft proteins that are altered after UVB-irradiation. Our data shows that levels of several raft proteins, including prohibitin (PHB), were changed after UVB-irradiation. PHB plays a critical role in many cell functions, such as cell-cycle control, cell proliferation, senescence, development, apoptosis, and tumor suppression. However, no reports implicate PHB-mediated apoptosis upon UVB irradiation. We now demonstrate that while the total PHB expression does not change, PHB is enriched in lipid rafts after UVB irradiation. Immunoprecipitation analysis shows that UVB alters the binding ability of PHB, Raf, and Akt, and decrease PHB phosphorylation. PHB siRNA knockdown cells exhibited an increased phosphorylation of Akt and ERK, and increased cell apoptosis after UVB irradiation. Based on these results, we propose that PHB regulates UVB-induced apoptosis through lipid raft translocation and alteration of Akt and Raf/ERK signaling pathways.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 3012. doi:1538-7445.AM2012-3012
Abstract 3025: CXCR4 is expressed in the nucleus of metastatic prostate cancer cells
Authors: Hewage Ayesha S. Don Salu , Hinton Cimona V.
Published: August 2012

Most prostate cancer-related deaths are due to the advancement of the tumor to a metastatic disease. The C-X-C Chemokine Receptor 4 (CXCR4) is a G-protein coupled receptor (GPCR) involved in the metastasis of various cancers, including the prostate. CXCR4 is generally regarded as a plasma membrane receptor; the canon concept of GPCR signaling holds that receptors located at the plasma membrane respond to secreted agonist stimulation. GPCRs, however, have also been observed at other intracellular organelles, including the nuclear membrane. Several cancer models have positively observed expression of a nuclear form of CXCR4 in advanced stage tissues and tumors with a poor prognosis. The significance of these receptors having a dualistic localization pattern is that nuclear receptors can escape from chemotherapy, since most therapeutics are hydrophobic small molecules targeted towards membrane bound receptors, which cannot pass through non-polar regions of the plasma membrane. An initial search of the CXCR4 sequence through the PredictNLS software program revealed a putative, nontraditional nuclear localization sequence, RPRK. We probed prostate cancer tissues for CXCR4 and observed a higher nuclear expression in high grade prostate tumors, compared to low grade, and no detectable CXCR4 in normal human prostate tissue by immunohistochemistry. Subcellular fractionations of prostate cancer cell lines (PC3, DU145 and 22RV1) and normal prostate epithelial cells (RWPE1) demonstrated positive expression of CXCR4 in both nuclear and cytoplasmic fractions, which were confirmed by immunocytochemistry analysis, independent of exogenous SDF1α stimulation. Based on our results, we suggest that CXCR4 is alternately expressed in the nucleus of advanced prostate cancer, which may enhance prostate cancer metastasis. To determine the origin of nuclear CXCR4, the a kinetic localization study confirmed that CXCR4 translocates to the nucleus from the plasma membrane at 37°C, which was inhibited when the same reaction was performed at 4°C. In conclusion, expression and localization of a nuclear CXCR4 may contribute to the advancement of prostate cancer to a metastatic disease, and aid tumors in escaping from therapy. Our studies will contribute to the development of therapeutics towards CXCR4, as current options are targeted towards membrane receptors, which may be ineffective if CXCR4 located and functional inside of the cell.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 3025. doi:1538-7445.AM2012-3025
Abstract 3028: Peroxisome proliferator-activated receptor ≤ (PPARδ) reveals a critical role in promoting the TGFβ-induced EMT and metastasis of non-small cell lung cancer cell (H460)
Authors: Lin Li-Chiung , Hsu Shih-Lan , Wu Chieh-Liang , Hsueh Chi-Mei
Published: August 2012

Although transforming growth factor ≤ (TGFβ) is anti-cancer identified, it was also known to promote tumor malignancy by enhancing the growth, epithelial to mesenchymal transition (EMT), tissue invasion and metastasis in a variety of cancer cells, including non-small cell lung cancers (NSCLCs). The aim of this study was to know the contribution of peroxisome proliferator-activated receptor ≤ (PPARδ) to TGFβ-promoted EMT and metastasis in NSCLCs. The degree of EMT, cell scattering, migration and invasion, and protein expression of PPARδ were first analyzed and compared between H460 and CH27 cells with or without TGFβ treatment (both are NSCLC cell lines). Chemical or shRNA blocking assay was also utilized to further confirm the importance of PPARδ in promoting TGFβ-induced tumor metastasis. Finally, signaling pathway(s) responsible for TGFβ/PPARδ-mediated metastasis was evaluated. The results demonstrated that TGFβ can effectively triggered the EMT, cell scattering, migration and invasion in H460 cell, but only a slight EMT was seen in TGFβ-treated CH27 cell. Meanwhile, PPARδ expression was induced by TGFβ in H460 cells but remained unchanged in CH27 cell. This indicated that PPARδ may involve in TGFβ-mediated metastasis. Co-treatment of TGFβ with GW9662 (a specific PPARδ inhibitor) significantly blocked TGFβ-promoted metastasis of H460 cell indicating the presence of PPARδ was indeed critical for TGFβ-attributed tumor metastasis. TGFβ appeared to act through P38 signaling pathway to trigger the expression of PPARδ and the subsequent activation of epidermal growth factor receptor (EGFR)/c-mesenchymal-epithelial transition factor (c-MET) signaling pathway and the reduction of E-cadherin that eventually led to the EMT and metastasis of H460 cell. Additionally, TGFβ also act through P38 to trigger the expression of β-catenin which could bind to and up-regulate the expression of PPARδ. Blocking of β-catenin activity, however, did not interfere with the metastasis indicating β-catenin may not play a direct role in promoting the metastasis of H460 cell. Nevertheless, we can not preclude the possibility that β-catenin may still act through PPARδ to regulate the metastasis of H460 cell, indirectly. In summary, TGFβ-induced EMT and metastasis in H460 cell was PPARδ-dependent and GW9662 revealed a therapeutical value in the control of NSCLCs (H460).

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 3028. doi:1538-7445.AM2012-3028
Abstract 303: Host-derived CCL2 plays a critical role in prostate cancer growth and skeletal metastasis
Authors: Fu Jiejun , Zhang Jian , Wang Jianhua , Lu Yi
Published: August 2012

We have previously reported that the presence of CC chemokine ligand 2 (CCL2) produced by prostate cancer (PCa) epithelial cells, stroma/osteoblasts, and bone marrow endothelial cells, is pro-tumorigenic for prostate cancer cells. CCL2 increases prostate cancer cell proliferation, migration, and survival and induces osteoclast formation. Moreover, the key role of CCL2 in the tumor growth and metastasis has been linked to its regulatory role in mediating monocyte/macrophage infiltration into the tumor microenvironment. Using a model of human PCa cells implanted in mice, Loberg R. et al. reported that anti-murine CCL2 neutralizing antibodies resulted in greater reduction of overall tumor burden compared to the use of anti-human antibody (anti-tumor cell-derived). This suggests that host-derived CCL2 may play a key role in prostate tumor growth and metastasis. Therefore, in this study, we have employed CCL2 knockouts which were interbred to SCID mice to generate colonies of homozygous SCID/CCL2−/− mice. PCa cells (PC3Luc) were injected into the left ventricle (Intracardiac-injection) of SCID/CCL2−/- and wild-type controls (n=20/group). The effects of deletion of CCL2 in the host on prostate cancer cell homing, growth in bone and bone destruction were evaluated for 4 weeks. In a parallel experiment, PC3Luc cells were subcutaneously implanted and tumor size was monitored weekly for 4 weeks. This parallel study addressed bone-specific vs. generalized influences of host-derived CCL2 on prostate cancer growth. We found that skeletal metastases occurred in 4/20 SCID/CCL2−/− mice vs 14/20 WT mice. In addition, X-ray photographs showed significantly fewer bone resorptive lesions in SCID/CCL2−/− mice vs. WT mice. Histology examinations confirmed x-ray findings. In the parallel experiment, PC3Luc tumor grew slower in SCID/CCL2−/- mice vs. WT mice. These results indicate that host-derived CCL2 production defines a permissive microenvironment for prostate cancer growth and skeletal metastasis. These findings may significantly impact the therapeutic field through targeting “the host” instead of “the tumor cells” in prostate cancer. Supported by U.S. Department of Defense PC061231 (J. Zhang), National Natural Sciences Foundation Key Project (81130046, J. Zhang) and National Natural Science Foundation Project (81171993, Y. Lu).

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 303. doi:1538-7445.AM2012-303
Abstract 3038: Delineating the role of Arid3B in normal and malignant differentiation of esophageal and cervical stratified squamous epithelia
Authors: Roy Lynn , Samyesudhas Serene , Dahl Karen Cowden
Published: August 2012

ARID3B is DNA binding protein overexpressed in neuroblastoma and ovarian cancer. We have determined that ARID3B expression is also upregulated during squamous epithelial differentiation (cervix, skin, and esophagus). Therefore, we wanted to assess the role of ARID3B in development of squamous cell carcinomas of the esophagus and cervix. In addition to examining the expression of ARID3B, we also wanted to determine the mechanism for ARID3B regulation in cancer and normal squamous cell epithelia. Recent evidence suggests that p63, specifically the ΔNp63α isoform, transcriptionally regulates Arid3B. p63 is a member of the p53 transcription factor family and is essential for the proliferative potential of stem cells in stratified squamous epithelia. p63 is also involved in various cancers including skin cancer and esophageal cancer. In esophageal squamous cell carcinoma, p63 is ubiquitously expressed and low levels are associated with a poor prognosis. We hypothesize that p63 regulates Arid3B in normal and malignant differentiation of stratified squamous epithelium. To evaluate ARID3B expression in cancer we performed immunohistochemistry on tissue microarrays using two independent Arid3B antibodies. Loss of nuclear Arid3B appears to be common in squamous cell carcinoma of cervix and esophagus. We also examined expression of ARID3B in a normal and a squamous cell carcinoma esophageal cell line. We are also examining the coordinate expression of p63 and Arid3B in serial sections of normal and malignant tissue sections of esophagus, cervix, and skin. We are also investigating the regulation of ARID3B in 3D cell culture models of esophagus differentiation. Our data suggests that misregulation of ARID3B may contribute to the development of cancer in stratified epithelia specifically of the cervix and esophagus.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 3038. doi:1538-7445.AM2012-3038
Abstract 3044: A new paradigm for ABCB6: Role in growth and proliferation
Authors: Polireddy Kishore K. , Chavan Hemant , Krishnamurthy Partha C.
Published: August 2012

ABCB6 is a mitochondrial ATP binding cassette (ABC) transporter whose expression is upregulated in a broad spectrum of primary human cancers, including hepatocellular carcinoma (HCC). We recently demonstrated that in hepatoma cells ABCB6 expression promotes growth and proliferation. In contrast, loss of ABCB6 expression in these hepatomas precipitates a delay in progression through G2/M phase of the cell cycle. As histone H3 is specifically phopshorylated during mitosis, we took advantage of the H3 phosphorylated antibody to separate G2 phase of the cell cycle from the M-phase. Using this approach, we demonstrate that loss of ABCB6 expression leads to a delay in M phase and not the G2 phase of the cell cycle. However, it is not clear how a mitochondrial transporter, originally characterized as a transporter of porphyrins, regulates cell growth. We have proposed two broad hypotheses to evaluate the mechanism by which ABCB6 regulates growth and proliferation; 1) ABCB6 functionally interacts with one or more of the cell cycle regulatory components, thus precipitating M phase delay; 2) ABCB6s’ location and function as a mitochondrial membrane transporter alters mitochondrial dynamics leading to some level of control over cellular proliferation. To test our proposed first hypothesis we have begun a systematic evaluation of the expression and function of cell cycle regulatory components in response to ABCB6 expression. Results from these studies demonstrate that ABCB6 expression alters the expression of cyclin-dependent kinase inhibitors p16, p21 and p27. In addition, yeast two-hybrid screening and protein interaction studies reveal that ABCB6 interacts with p21 and a novel tumor susceptibility protein-101 (TSG-101). TSG 101 co-localizes with microtubule organizing centers and mitotic spindles during mitosis and its deficiency is associated with abnormalities in microtubules, genetic instability and carcinogenesis. In this report, we provide evidence of the physical and functional interactions between ABCB6 and cell cycle regulatory components and explore the significance of these interactions to growth and proliferation.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 3044. doi:1538-7445.AM2012-3044
Abstract 3046: Cathepsin B and uPAR downregulation sensitizes glioma initiating cells to radiation induced cell cycle arrest
Authors: Gopinath Sreelatha , Malla Rama Rao , Alapati Kiranmai , Tsung Andrew J. , Rao Jasti S.
Published: August 2012

Ionizing radiation is the standard treatment for glioblastoma multiforme (GBM). Radiation and chemoresistance have been attributed to a small population of cells known as glioma stem cells (GSCs) or glioma initiating cells (GICs). In the present study, we studied the effect of ionizing radiation on the progression of cell cycle of glioma initiating cells, non glioma initiating cells (non-GICs), and the respective parental cell lines (U251 and U87). Initial experiments showed that GICs were resistant to lower doses of radiation (3 and 5 Gy) as compared to parental and non-GICs. Radiation dosage of 10 Gy induced significant G2/M arrest as early as 12 and 24 hours in non-GICs (U251 and U87) and parental cell lines (U251 and U87), respectively and a low percentage of GICs were observed in the G2/M phase 48 hours after radiation. Apart from cathepsin B and uPAR, expression levels of cyclin B1, pcdc2, pchk2 and pERK were also elevated when cells were exposed to radiation. shRNA-mediated simultaneous knockdown of cathepsin B and uPAR (pCU) decreased radiation-induced expression of cyclin B1, pcdc2, pchk2 and pERK and induced apoptosis. Further, immunoblot analysis indicated that cathepsin B and uPAR downregulation reduced the expression of neural stem cell markers, such as CD133, Sox-2 and Bmi-1. Activation of pERK played an important role in inducing the G2/M arrest of GICs of both cell lines as its inhibition induced cell differentiation and sensitized the cells to radiation. Irradiation induced aggressive tumors in vivo and the knockdown of uPAR and cathepsin B significantly decreased radiation-induced tumor growth. Thus, these results indicate that uPAR and cathepsin B downregulation sensitized GICs to ionizing radiation and targeting these proteins could be an efficient approach to eradicate tumors, particularly GICs in the tumor bulk.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 3046. doi:1538-7445.AM2012-3046
Abstract 3048: High frequencies of centrosome amplification in MMTV-Her2/Neu pre-malignant mammary lesions and in Her2+ breast cancer cells suggest that centrosome amplification is involved in Her2-dependent breast cancer biogenesis
Authors: Harrison Mary Kathryn , Saavedra Harold I.
Published: August 2012

Centrosome amplification (CA) is a major force in cancer initiation and progression, as it generates aneuploidy and chromosome instability. Observations in breast tumors show that adenocarcinomas have a higher frequency of centrosome defects when compared to normal breast tissue. Similar phenotypes are also found in pre-malignant lesions and in pre-invasive in situ ductal carcinoma, suggesting that these aberrations occur early in breast carcinogenesis. Identification of the pathways and regulatory molecules involved in the generation of CA is essential to understanding the role of CA in breast tumorigenesis. Our published results showed that CA is specific to the Her2 effector Ras at mammary pre-malignancy and in tumorigenesis. Due to the strong association between Her2 over-expression and CA in human breast cancers, our goal is to identify cell and centrosome cycle regulators that are de-regulated by aberrant Her2 signaling in human and mouse mammary epithelial cells. Our results show breast cancer cells over-expressing Her2 and pre-malignant mouse mammary hyperplasias expressing Her2/Neu harbor CA. In Her2+ cells that display a plethora of genetic alterations, this process is dependent on Her2, as revealed by shRNA and shRNA downregulation of Her2. Human breast cancer cells expressing Her2 show up-regulation of cyclin D1 and other important centrosome regulatory molecules. In fact, abrogation of Cdk4 or Cdk6, catalytic partners of cyclin D1 reduced the frequencies of CA in Her2+ cells. In contrast, downregulation of Cdk2 did not affect CA. We want to elucidate the mechanism responsible for CA in Her2+ breast cancers. Cells overexpressing Her2 also display increased frequencies of binucleation, suggesting a defect in cytokinesis. We propose that in Her2+ cells, Cdk4 signals CA through either by hyperphosphorylation of NPM at Thr199, a site that negatively regulates centrosome duplication, and/or through the Rb/E2F pathway.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 3048. doi:1538-7445.AM2012-3048
Abstract 3055: PD-0332991, a selective cyclin-dependent-kinase 4/6 Inhibitor, upregulates multiple genes promoting invasion and metastasis in pancreatic ductal adenocarcinoma
Authors: Liu Fang , Korc Murray
Published: August 2012

Deregulation of the Cyclin D-CDK4/6-Rb-E2F signaling pathway is among the most commonly found aberrations in human pancreatic ductal adenocarcinoma (PDAC). PD-0332991 is an orally available, highly specific and reversible inhibitor for Cdk4 and Cdk6, and demonstrates in vitro and in vivo growth inhibitory effects in multiple tumor types. However, the potential usefulness of PD-0332991 in PDAC is currently unknown. In this study, we examined the effects of PD-0332991 on multiple human pancreatic cancer cell lines, and we found that this agent inhibited Rb phosphorylation and E2F target gene expression, and induced G0/G1 cell cycle arrest. However, the growth inhibitory effect was only transient, due to the rapidly emerging compensatory changes of the G1/S machinery components, including upregulation of CyclinD1, Cdk4, and Cdk6, and downregulation of Rb, p107, and p130. Microarray analysis revealed that incubation with PD-0332991 upregulated multiple genes which promote pancreatic cancer invasion, metastasis, angiogenesis, and chemoresistance, including LAMC2, CYR61, SERPINE1, F3, ABCA1, ASNS, and DUSP1. In addition, using matrigel-coated transwell invasion chambers, we demonstrated that incubation with PD-0332991 enhanced the invasiveness of human pancreatic cancer cells. These observations suggest that PD-0332991 may have the potential to cause deleterious effects in PDAC by modulating gene expression in a manner that could promote cancer spread, metastasis, and chemoresistance.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 3055. doi:1538-7445.AM2012-3055
Abstract 3122: The DNA-PK inhibitor NU7441 inhibits non-homologous end joining, enhances radio- and chemosensitivity and increases dependence on homologous recombination in hepatocellular carcinoma cell lines
Authors: Cornell Liam , Munck Joanne M. , Reeves Helen L. , Curtin Nicola J.
Published: August 2012

Background DNA double-strand breaks (DSBs), the most cytotoxic lesions induced by ionizing radiation (IR) and anticancer drugs such as topoisomerase II poisons (e.g., doxorubicin), are repaired by non-homologous end joining (NHEJ) and homologous recombination (HR). DNA-dependent protein kinase (DNA-PK), which initiates NHEJ, is up-regulated in hepatocellular carcinoma (HCC) (GEO profiles), possibly contributing to anticancer therapy resistance. To assess DNA-PK as a potential therapeutic target for chemo- and radio-sensitisation in HCC we determined the effect of the DNA-PK inhibitor, NU7441, on DSB repair and cytotoxicity in HCC cells. Methods DNA-PK protein levels and activation by IR (Western blot), DSB levels (y-H2AX foci), HR (RAD51 foci), cell growth (DAPI fluorescence) and cytotoxicity (colony formation) following exposure to IR or doxorubicin was determined in a panel of 6 hepatoma cell lines (HepG2, Hep3B, Huh7, SNU-182, SNU475 and PLC/PRF/5). Results DNA-PK protein concentration and activity did not vary significantly across the panel (±24% and ±37%, respectively) but there were cell-specific sensitivities to IR and doxorubicin (e.g. HepG2 2-fold more resistant than Hep3B). NU7441 significantly sensitised all cells to both doxorubicin (average PF50 4.3±3.0) and IR (average PF50 3.9±1.1) in growth inhibition assays and significantly reduced survival (4.8 to 3.3-fold) in colony forming assays. Following exposure to IR, NU7441 significantly delayed yH2AX focus clearance in all cell lines (e.g. only 13% cleared at 4 hr compared to 50% in control), but increased RAD51 focus formation (3-fold). Conclusion While chemo- and radio-sensitivity in HCC cells was not dependent on DNA-PK expression or activity, NU7441 causes greater than 2-fold chemo- and radiosensitisation in all cells. This was accompanied by a substantial reduction in the rapid phase of DNA repair (NHEJ-dependent) and a shift to a greater reliance on the slower HR repair. DNA-PK inhibitors may have potential as chemo- and radio-sensitisors in hepatoma patients.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 3122. doi:1538-7445.AM2012-3122
Abstract 3148: Frequent epigenetic inactivation of keap1 gene in non small cell lung cancer
Authors: Muscarella Lucia Anna , Parrella Paola , la Torre Annamaria , D'Alessandro Vito , Barbano Raffaela , Pellegrini Fabio , Tancredi Antonio , Guarnieri Vito , Coco Michelina , Balsamo Teresa , Vendemiale Gianluigi , Maiello Evaristo , Fazio Vito Michele
Published: August 2012

The KEAP1/NRF2 pathway is a master regulator of several redox-sensitive genes implicated in resistance of tumour cells against chemotherapeutic drugs. Recent data suggest that epigenetic mechanisms may play a pivotal role in the regulation of KEAP1 expression. We performed a comprehensive genetic and epigenetic analysis of the KEAP1 gene in 47 Non Small Cell Lung Cancer tissues and 12 normal lung specimens. Promoter methylation analysis was performed using a quantitative methylation specific PCR assay in real time. Methylation at the KEAP1 promoter region was detected in 22 out of the 47 NSCLCs (47%) and in none of the normal tissues analyzed. Somatic mutations were detected in 7 out of the 47 tumours (15%), and loss of heterozygosity (LOH) in 10 out of the 47 (21%) of the cases. Overall, we found at least one molecular alteration in 57% of the cases. Approximately one third of the tumours had two alterations and this feature was associated with higher risk of disease progression in univariate COX regression analysis (HR=3.62; 95% CI 1.24-10.65, p=0.02). This result was confirmed by Kaplan-Meier analysis which demonstrated an association between worst outcome and KEAP1 double alterations (p=0.01, Log rank test). Our results further suggest that deregulation of the NRF2/KEAP1 system could play a pivotal role in the cancerogenesis of NSCLC. In addition identifying patients with KEAP1 genetic and epigenetic abnormalities may contribute to disease progression prediction and response to therapy in lung cancer patients.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 3148. doi:1538-7445.AM2012-3148
Abstract 3153: H. pylori infection enhances the degradation of Drosha through regulating its acetylation-ubiquitination switches
Authors: Tang Xiaoli
Published: August 2012

microRNAs are a class of short non-protein coding RNAs with length of ∼22nt which play important regulatory roles in the cell functions by inhibiting their target protein expression. The biogenesis of microRNAs is a multistep process which is initiated in the nucleus by the RNase III enzyme Drosha. Our previous work and the work from others showed that Drosha protein level affected the biogenesis of microRNAs. Accumulating evidence shows that overall microRNA levels in the stomachs of H. pylori-infected patients are decreased and that this may relate to the promotion of gastric cancer by this bacterium. But the underlying mechanisms largely remain unknown. Here we show that H. pylori infection enhances the ubiquitin-proteosome pathway of Drosha degradation which is constitutively active in cells. Of the microRNA regulatory proteins, Drosha is more sensitive to ubiquitin-proteasome pathway-induced degradation than Dicer, DGCR8 or exportin-5. Activated ubiquitin molecules are ligated to the N-terminal lysines of Drosha leading to its degradation. There are 13 lysine residues on the N-terminus of Drosha. Truncation or site-directed mutagenesis showed multiple lysines involved in the ubiquitination-induced degradation of Drosha. Those lysine residues are also the acetylation sites by multiple acetyl transferases such as p300, CBP. Acetylation of Drosha on those N-terminal lysine sites prevents Drosha from ubiquitination and thereby prevents its degradation. Our data indicate that H. pylori infection enhances the degradation of Drosha through regulating the acetylation-ubiquitination switches on Drosha. Our findings provide a potential therapeutic target for mitigating the effects of H.pylori infection, including gastric cancer.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 3153. doi:1538-7445.AM2012-3153
Abstract 316: Peritoneal carcinomatosis depends for growth and spreading on endogenous inflammatory cues generated by infiltrating macrophages
Authors: Cottone Lucia , Valtorta Silvia , Capobianco Annalisa , Monno Antonella , Belloli Sara , Fazio Ferruccio , Moresco Rosa Maria , Rovere-Querini Patrizia , Manfredi Angelo A.
Published: August 2012

Peritoneal carcinomatosis is the most common terminal feature of abdominal cancers. Interfering with the peritoneal immune microenvironment is a promising tool for combinational therapy. Preclinical studies on peritoneal carcinomatosis have been hampered by the limited availability of models as well as non-invasive methods to follow tumor growth. We set up ad hoc models via the orthotopic injection of murine cells lines in immuno-competent mice and followed tumor growth by imaging with [18F]2-fluoro-2-deoxy-D-glucose-PET ([18F]-FDG-PET). Colon carcinoma (MC38), Mouse Ovarian Surface Epithelial Carcinoma cell line (MOSEC) of C57BL/6 origin and adenocarcinoma cells (TS/A) of Balb/C origin were injected intraperitoneally in syngeneic mice. The models nicely recapitulated the histological features of the human disease: carcinoma cells distributed along the cavity and yielded several masses attached to the peritoneal lining. Animals were longitudinally followed by imaging with [18F]-FDG-PET: tumor lesions selectively up-took the radioactive tracer and we observed a significant correlation between lesion dimension and metabolic radioactive volume. We characterized leukocyte composition of the peritoneal liquid of tumor bearing mice by multicolor flow cytometry, performing peritoneal lavage on live animals at various time points during tumor growth. Tumor spreading induced the recruitment of leukocytes, among which the most relevant population was represented by CD45+CD11b+F4/80+ monocytes/macrophages. The depletion of peritoneal monocytes/macrophages, via administration of clodronate encapsulated in liposomes, lead to a substantial reduction of tumor burden as well as leukocyte recruitment, and was paralleled by a decrement in the extent of radioactivity distribution when imaging mice with [18F]-FDG-PET. Moreover we found out that colon carcinoma cells upon in-vitro treatment with stress-inducing stimuli, such as starvation and chemotherapeutic agents exposure, produced factors involved in leukocytes recruitment: this behavior was directly linked to the activation of autophagic and apoptotic intracellular pathways. In conclusion, [18F]-FDG-PET imaging allowed the non-invasive detection of peritoneal adenocarcinoma lesions which spreading and growth was dependent on the production of factors involved in leukocytes recruitment, specifically on peritoneal monocytes/macrophages.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 316. doi:1538-7445.AM2012-316
Abstract 3163: Exploration of microRNA-34a effects in human glioma cell lines
Authors: Kofman Alexander , Guessous Fadila , diPierro Charles G. , Dupart Evan , Bao Yongde , Dhamala Susan , Letson Christopher , Letson Christopher , Park So Yeon , Marcinkiewicz Lukasz , Abounader Roger
Published: August 2012

We have previously demonstrated that miR34a targets and downregulates multiple oncogenes, and therefore it may be considered as a potent tumor suppressor factor. In this report we show that miR34a expression is strictly dependent on the ability of major tumor suppressor protein TP53 to bind to miR34a transcriptional regulatory elements. In order to further investigate the effects of miR34a we generated a panel of human glioma cell lines where both miR34a and copGFP gene reporter are expressed in a tet-inducible manner. The constitutive expression of cyan fluorescent protein, the mutant GFP derived from Aequorea Victoria, and tet-inducible expression of copGFP derived from Anthozoa allows co-localizing and tracking both tet-induced and non-induced cells in vivo. We present data indicating that miR34a-caused inhibition of cell proliferation both in vitro and in vivo is due to the down-regulation of cyclin D1 and transcriptional factors E2F3 and E2F5. We show that miR199a, which targets other cyclins and cyclin-dependent kinases and therefore complements the action of miR34a, is up-regulated upon miR34a overexpression. miR199a-5P and miR199a-3P, but not miR34a, target E2F6 and USP7 correspondingly. Overexpression of miR34a using tet-inducible cell lines and lentiviral vectors downregulated E2F6 and USP7 on the 5th day after induction/transduction. However, at 48-72 hours after p53 overexpression accompanied by the modest upregulation of miR34a no changes in miR199a levels were observed. The results indicate that miR34a induces miR199a overexpression indirectly, most probably at the transcriptional level, thus eliciting the synergistic anti-tumor effects. We have also found that overexpression of miR34a in tet-inducible manner significantly inhibits the growth of brain tumors and prolongs the survival of immunodeficient animals. Finally, we show that miR34a targets and downregulates phosphoprotein enriched in astrocytes-15, which has been reported to promote autophagy and contribute to the resistance to radiation therapy.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 3163. doi:1538-7445.AM2012-3163
Abstract 3164: MiR-134 expression is oncogenic for oral cancer
Authors: Liu Chung-Ji , Lin Shu Chuan , Chang Kuo-Wei , Tsai Meng-Miao Tsai
Published: August 2012

Introduction Oral squamous cell carcinoma (OSCC) is one of the most prevalent malignant diseases around the worldwide. Understanding the pathogenetic basis of these tumors will bestow profound benefits in resolution of this disease, to validate individualized therapy and reduction in medical resources consumption. MicroRNA (miRNA) is a short, non-coding RNA that regulates gene expression by controlling mRNA translation. Which can affect biological and pathological processes. Dysregulation of miRNA function might lead to human disease including human cancers. Upregulation of miR-134 in OSCC was observed in a our previous study. However, the clinical implications and functions of miR-134 in oral tumorigenesis remain unclear. Methods Quantitative RT-PCR was used to analyze the miR-134 expression in OSCC tissue pairs. The oncogenic phenotypes including proliferation, migration and anchorage-independent colony formation were assayed in cells with miR-134 expression or miR-134 blockage. The xenografic tumorigenecity was assayed on nude mice model. TargetScan predicted WW domain-containing oxidoreductase (WWOX) a tumor suppressor gene to be putative targets of miR-134. To test the targeting activity of miR-134, antisense sequences complementary to miR-134 sequences and the 3β untranslatedregion (UTR) of WWOX containing predictive miR-134 target sites were cloned into the pCMV-LacZ plasmid at the 3α-end of the lacZ coding sequence; these reporter plasmids were designated miR-134-asR and pCMV-LacZ-WWOX3αUTR, respectively. Results miR-134 was found to be markedly upregulated in cancerous tissues than in non-cancerous matched tissues in OSCC tissue pairs. Higher miR-134 was associated with the more advanced tumor size and vascular invasion. Transfection of miR-134 precursor transiently upregulated miR-134 expression in OSCC cells. It increased oncogenic potential of OSCC cells. Conversely, the in vitro oncogenic potential of OSCC cells was attenuated after blocking of miR-134 expression. Stable SAS OSCC cell subclone with ectopic miR-134 expression was established by lentiviral delivery. Ectopic miR-134 expression increased the tumorigenicity of SAS subclone. Downregulation of WWOX mRNA expression and protein expression was found in SAS-miR-134 cells compared with controls. Conversely, upregulation of WWOX mRNA expression and protein on miR-134 LNA treatment relative to controls was found. Conclusion This identified for the first time that miR-134 is oncogenic to oral epithelium and its expression level could be validated as a diagnostic marker of OSCC. Our findings suggest that miR-134 contributes to the development of OSCC by targeting WWOX.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 3164. doi:1538-7445.AM2012-3164
Abstract 3172: Role of miRNA-211in melanocytes and melanoma
Authors: Maddodi Nityanand , Madhavan Shajil , Devi Sulochana , Jayanthy Ashika , Setaluri Vijayasaradhi
Published: August 2012

MicroRNAs (miRNAs) are small non-coding regulatory RNAs that regulate gene expression. Evidence is accumulating that miRNAs are involved in almost all aspects of tumor biology including tumor cell survival, proliferation and migration. Here, we report that miRNA-211, which maps to the sixth intron of TRPM1 gene (a suppressor of melanoma metastasis), is highly expressed in primary melanocytes and its expression is reduced in primary and metastatic melanoma cell lines. Expression of miRNA-211 correlates with expression of TRPM1, a transient receptor potential family member calcium channel protein that we showed to be involved in regulation of melanocyte calcium homeostasis and melanin pigmentation. Inhibition of miRNA-211 expression by anti-miR211 inhibited intercellular Ca+2 update and the growth of rapidly growing melanocytes. Ectopic expression of miRNA-211in melanoma cells inhibit growth and reduced their migration. Regulation of miRNA-211 and its function in melanocytes and melanoma have not been well understood. We show that ectopic expression of p53 (a tumor suppressor) in melanocytes increase miRNA-211 expression and decrease TRPM1 expression. Inhibition of miRNA-211 did not change TPRM1 expression in melanocytes. Additionally, we show that 1.4 kb intron 6 genomic region of TRPM1 which contain miRNA-211 region is sufficient to activate miRNA-211 expression. And 1.4 kb of 6th intron luciferase reporter plasmid transfection followed by luciferase assay showed increase in promoter driven luciferase activity. These data suggests that the presence of putative promoter region of miRNA-211 in the sixth intron of TRPM1 gene. We propose that activation of endogenous miRNA-211 expression or targeted delivery of miR-211 in melanoma is a potential therapeutic option for treatment of cutaneous melanoma.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 3172. doi:1538-7445.AM2012-3172
Abstract 3226: PKM2 metabolic activator slows lung cancer xenograft growth
Authors: Parnell Mark , Foulks Jason M. , Nix Rebecca , Luo Bai , Senina Anna , Xu Yong , Saunders Michael , Ho Koc-Kan , McCullar Michael V. , Kanner Steven B.
Published: August 2012

Tumor cells primarily utilize aerobic glycolysis, rather than oxidative phosphorylation, to metabolize glucose (the Warburg effect). The M2 splice form of pyruvate kinase (PKM2), the enzyme catalyzing the rate-limiting final step of glycolysis, is highly upregulated in tumors. Unlike the M1 splice form (PKM1), a constitutively active tetramer found predominantly in non-cancerous tissues, PKM2 is an inactive dimer under normal physiological conditions. Tetramerization of PKM2 requires binding of the allosteric activator fructose-1,6-bisphosphate (FBP), an upstream glycolytic intermediate, resulting in a fully active enzyme. Inactivation of PKM2 by cancer cells may allow glycolytic intermediates to be diverted into other biosynthetic pathways necessary for biomass production. The finding that PKM2 rather than PKM1 expression enhances tumorigenicity suggests that activators of PKM2 may have anti-tumor properties. We have identified and developed a series of small molecule PKM2 activators that exhibit low nM activation activity in biochemical and cell-based assays that measure pyruvate and ATP production. The extent of activation of these compounds is equal to or greater than that of FBP in biochemical assays. In addition, preliminary studies show that PKM2 activators inhibit the growth of lung cancer cell lines in vitro. The current lead compound was tested in established subcutaneously implanted A549 lung adenocarcinoma xenografts, where we observed a statistically significant decrease in tumor growth, with no observable toxicity. These data suggest that this class of PKM2 activators is effective as tumor cell metabolic regulators with anti-tumor activity for lung cancer and potentially other malignancies.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 3226. doi:1538-7445.AM2012-3226