bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 260: Identification of the role of linker histone H1 in estrogen receptor binding and activity
Authors: Cato Laura , Brown Myles
Published: June 2012

The activity of estrogen receptor (ER) in the nucleus is a highly dynamic process, which is tightly regulated by many factors. Among the molecules proposed to facilitate ER activity are proteasome components, chromatin-remodeling complexes, heat shock proteins and histones. Particularly the linker histone H1 seems important, as it is essential to the stability of the higher-order chromatin structure and has been associated with the regulation of gene expression for many years. Eleven linker histones have been identified in humans to date, differing in their timing of expression, extent of post-translational modification and affinity to DNA in chromatin. However, their exact function and ability to differentially affect gene expression are not as clearly understood. It seems probable that linker histones need to be removed, reduced in amount or somehow modified during transcription in order to allow access to the transcription machinery and that these processes are different for the different linker histone subtypes. Here we show that removal of linker histone H1 is a prerequisite for the full activation of ER-regulated target genes in ER positive breast cancer cells. This process is mediated through the activity of the cyclin-dependent kinase 2 (CDK2), which phosphorylates H1 in a hormone-dependent manner, and thereby loosens the interaction of the linker histone with DNA in chromatin. The extent of phosphorylation differs significantly between the different subtypes, suggesting a differential involvement of the H1s in ER-mediated gene expression. Collectively, our results show that H1 dissociation is required for ER-mediated gene expression in breast cancer and that the H1 subtypes may play distinct functional roles in the transcriptional regulation of ER target genes.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 260. doi:10.1158/1538-7445.AM2011-260
Abstract 2602: FoxM1 is an attractive therapeutic target in a subset of papillary thyroid cancers
Authors: Ahmed Maqbool , Bavi Prashant , Hussain Azhar R. , Jehan Zeenath , Olyan Aishah S. , Bu Tiezheng R. , Al-Nuaim Abdulrehman , Al-Sobhi Saif , Amin Tarek , Uddin Shahab , Al-Kuraya Khawla S.
Published: June 2012

The FoxM1 transcription factor promotes the pathogenesis of several malignancies. However, little is known about its expression and function in papillary thyroid cancers (PTC). In the present study we investigated the role of FoxM1 in the pathogenesis of PTC in a large series of PTC in a tissue micro array (TMA) format followed by studies using PTC cell lines and nude mice. Our data showed that expression of FoxM1 was over expressed in 28.4 % (141/496) of PTC and significantly associated with activated AKT (p<0.0001) and matrix metalloproteinase-9 (MMP-9) expression (p=0.0004). FoxM1 over expression was also strongly associated with antiapoptotic markers, XIAP (p=0.0024), and Bcl-Xl (p=0.0014). In vitro data using PTC cell lines showed that inhibition of FoxM1 by thiostrepton resulted in inhibition of proliferation and induction of apoptosis in a dose dependent manner. In addition, thiostrepton treatment caused downregulation of SKP2, and consequent increase expression of p21 in PTC cell lines. We also found that down-regulation of FoxM1 reduced the expression of MMP-2, MMP-9 and vascular endothelial growth factor, resulting in the inhibition of migration, invasion, and angiogenesis in PTC cells. Furthermore, pharmacological inhibition of FoxM1 or siRNA targeted against FoxM1 triggered caspase dependent apoptosis in PTC cells. Finally, treatment of PTC cell line xenografts with thiostrepton resulted in growth inhibition of tumors in nude mice via downregulation of FoxM1 and MMP9. Altogether, our results suggest that FoxM1 and its associated signaling pathway may be a potential target for therapeutic intervention for treatment of PTC.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 2602. doi:10.1158/1538-7445.AM2011-2602
Abstract 2605: Identification and development of NVP-HSP990, a potent and orally active Hsp90 inhibitor for cancer treatment
Authors: Gao Zhenhai , Machajewski Timothy , Menezes Daniel , Jensen Michael Rugaard , Yu Karen , Guy Chantale
Published: June 2012

Hsp90 is recognized as a potential target for the treatment of cancer, due to its chaperone functions that are required for maintaining the stability and/or active conformation of signalling molecules essential for tumorigenesis. The development of small molecule Hsp90 inhibitors has become an extremely competitive field of research. Here for the first time we present biological and pharmacological properties of NVP-HSP990, a potent oral Hsp90 inhibitor discovered by Novartis. In vitro, NVP-HSP990 potently inhibits all 4 isoforms of Hsp90 (Hsp90α, Hsp90β, TRAP-1 and GRP94) and has no major activities in a safety pharmacology panel of kinases, receptors and enzymes evaluated. NVP-HSP990 demonstrates broad-spectrum anti-tumor activities in tumor cell lines (IC 50s ranging from 4-35 nM) and primary patient samples (mean IC50 =49 nM). In vivo, NVP-HSP990 is highly bioavailable across species and a single oral administration of 15 mg/kg induces sustained target inhibition up to 7 days as indicated by downregulation of client protein (c-Met) and upregulation of Hsp70 in a cMet overexpressing gastric GTL16 xenograft tumor model. Weekly administration of NVP-HSP990 was efficacious in a broad range of mouse and rat human tumor xenograft models driven by well defined oncogenic Hsp90 client proteins. In summary, NVP-HSP990 represents a novel class of oral Hsp90 inhibitors with unique and superior pharmacological and drug-like properties. NVP-HSP990 is currently being evaluated in Phase I clinical trial in advanced solid tumors. In addition, we will present multiple secreted biomarkers for Hsp90 that were identified through a novel in-silico data mining approach. Several of these biomarkers have been validated both in vitro and in vivo, and have the potential to be utilized as clinical pharmaco-dynamic markers in the development of Hsp90 inhibitors.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 2605. doi:10.1158/1538-7445.AM2011-2605
Abstract 261: Emerging roles for the CREB regulated transcription coactivators (CRTCs) in oncogenesis
Authors: Amelio Antonio L. , Dorsey Frank C. , Steeves Meredith A. , Southern Mark R. , Young Brandon M. , Lawani Mariam B. , Prater Stephanie M. , Alperstein Adam S. , Cleveland John L. , Conkright Michael D.
Published: June 2012

Oncogenesis is a complex, multi-factorial process of cellular transformation that leads to the development of many types of cancers. The factors that contribute to this process reprogram normal cellular functions, including metabolic pathways, and allow uncontrolled cell growth. The CRTC family of CREB coactivators, in conjunction with CBP/p300, cooperate in the regulation of cAMP-inducible genes involved in cell survival, proliferation, glucose metabolism, and adaptive mitochondrial biogenesis. A subset of tumors share a common t(11;19)(q21;p13.1) translocation that forms a chimeric oncogene by fusing CRTC1 to the NOTCH coactivator MAML2. Consequently, the CRTC1/MAML2 translocation induces the aberrant expression of genes regulated by CREB and NOTCH and the deregulation of these target genes is believed to cause tumorigenesis. We demonstrate that a gain-of-function activity by the CRTC1/MAML2 oncoprotein promotes interactions with the MYC:MAX network. This interaction is specific as neither CRTC1 or MAML2 parental proteins activate MYC:MAX complexes. Specifically, RNA-seq analysis revealed that a significant proporation of genes involved in key aspects of cell growth, survival, and metabolism within the MYC:MAX and CREB transcription networks are induced by CRTC1/MAML2. Analysis of cellular transformation by RK3E foci formation assays identified a synergistic effect of MYC expression on CRTC1/MAML2-induced transformation and this can be blocked by a dominant negative MYC molecule. Furthermore, in-frame deletions of CRTC1/MAML2 that lack transforming activity are unable to induce the expression of MYC-responsive reporters revealing a critical role for MYC target genes in CRTC1/MAML2-induced cell growth and transformation. Collectively, these studies indicate that CRTC1/MAML2 promotes cellular transformation through cooperative activation of MYC and CREB pathways thereby challenging current paradigms which suggest that translocations function through aberrant activation of parental pathways.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 261. doi:10.1158/1538-7445.AM2011-261
Abstract 2617: MPC-3100, a synthetic Hsp90 inhibitor, induces biomarker changes in vitro and in vivo
Authors: Baichwal Vijay R. , Brown Brita , Robinson Rosann , Cimbora Daniel , Wettstein Daniel , Beelen Andrew P. , Mather Gary G. , Carlson Robert O.
Published: June 2012

Introduction: MPC-3100 is a fully synthetic, orally bioavailable, Hsp90 inhibitor in clinical development. It is broadly active in xenograft models with anti-tumor activity ranging from tumor regression to tumor growth inhibition in many cancer types including colon, gastric, ovarian, prostate, breast, lung and myeloid leukemia. Here we evaluate the effect of MPC-3100 on stability of client proteins in cells and xenograft tumors. We also determine the effect on Hsp70 protein levels, a biomarker of Hsp90 inhibition, in peripheral blood mononuclear cells (PBMCs) from cancer patients receiving MPC-3100.

Methods: Her2, Akt, Cdk4, c-Raf and Hsp70 client protein levels were monitored in cell culture with protein immunoblots. Formalin-fixed, paraffin-embedded sections of xenograft tumors from mice dosed orally with MPC-3100 were analyzed by immunohistochemistry (IHC) to monitor changes in Her2, Akt and Hsp70 protein levels. To monitor changes in Hsp70 in cancer patients treated with MPC-3100, PBMCs were collected prior to drug administration, 8 and 24 hours post-dose on Day 1 and 24 hours post-dose on Days 7 and 21 of the first treatment cycle. Hsp70 protein levels were determined by ELISA.

Results: Exposure of HCT-116, NCI-N87 and DU-145 cells to MPC-3100 in vitro resulted in a time-dependent reduction in client protein levels with maximal reduction by 24 hours. The IC50 values for client protein reduction ranged from 0.1 μM to 0.5 μM, comparable to the cellular cytotoxicity values of MPC-3100 at 72 hours for the various cell lines. IHC revealed reduction in Her2 and Akt protein in N87 xenografts in mice given a single oral dose of 200 mg/kg MPC-3100 relative to tumors from animals dosed with vehicle. Healthy volunteer PBMCs exposed to 1 μM MPC-3100 for 24 hours ex vivo revealed a reduction in Akt, c-Raf and Cdk4 protein levels ranging from 50% to 90%. PBMCs from cancer patients receiving MPC-3100 showed an increase of 28 to 589 ng of Hsp70 protein per mg total protein over baseline by Day 8. The increase in Hsp70 expression was seen as early as 8 hours after the first dose and sustained through at least Day 22.

Conclusions: The changes in client proteins and biomarkers observed in cells and tumor xenografts exposed to MPC-3100 confirm that the cellular cytotoxic activity and anti-tumor activity in xenografts are a result of Hsp90 inhibition. The consistent increase in Hsp70 expression in PBMCs from cancer patients receiving MPC-3100 indicates that Hsp90 function is inhibited in patients at doses that have been well tolerated in the clinic.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 2617. doi:10.1158/1538-7445.AM2011-2617
Abstract 2638: Association between Adriamycin-induced autophagy and senescence in breast cancer cells
Authors: Di Xu , Bristol Molly L. , Valerie Kristoffer , Hawkins Amy J. , Gewirtz David A.
Published: June 2012

Previous studies from this laboratory demonstrated that the topoisomerase II poison, Doxorubicin, at a clinically relevant concentration of 1µM, induced a pronounced senescence response in breast cancer cells. Doxorubicin was also observed to generate a time-dependent increase of autophagy within 72 hrs by multiple approaches, including acridine orange staining (AOS), downregulation of p62 (indicative of autophagic flux), LC3 puncta formation and electron microscopy. The current studies were designed to investigate the potential relationship between senescence and autophagy in response to Doxorubicin in breast cancer cells.

Silencing of ATM by the pharmacological inhibitors, caffeine or KU55933, or by small interfering RNA abrogated doxorubicin-induced senescence, as demonstrated by decreased β -galactosidase staining as well as down-regulation of p21 expression. At the same time, silencing/attenuation of ATM suppressed autophagy, based on decreased conversion of LC3-I to LC3-II by Western blotting, and reduced acridine orange staining.

Free radicals are well-established to induce senescence, and Doxorubicin-induced senescence has been shown to be associated with free radical generation. We demonstrate that the antioxidants, glutathione (GSH) or N-acetyl cysteine (NAC), were able to collaterally suppress Doxorubicin-induced senescence and autophagy, based on reduced β-Gal staining, LC3-I to II conversion and activation of ATG5, respectively. Similarly, both senescence and autophagy induced by the topoisomerase I inhibitor, camptothecin, were suppressed by GSH or NAC.

Silencing of p53 or p21 expression inhibited both Doxorubicin-induced senescence and autophagy in both breast and colon cancer cells. In contrast, a blockade of autophagy either by the pharmacological inhibitors, 3-methyl adenine or chloroquine, or genetic silencing of ATG5 or ATG7 expression, only served to delay the onset of Doxorubicin-induced senescence. Similarly, a delayed senescence response was observed when autophagy induced by camptothecin or H2O2 was blocked by chloroquine or bafilomycin in MCF-7 cells.

Our studies suggest that: 1. Free radicals, ATM, p53 and p21 are involved in the signaling pathways that promote the autophagic and senescence responses to chemotherapeutic agents; 2. autophagy acts to accelerate senescence; and 3) while chemotherapy induced autophagy and senescence are closely associated, senescence can likely occur in the absence of autophagy.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 2638. doi:10.1158/1538-7445.AM2011-2638
Abstract 2649: Attenuation of JNK phosphorylation by 4-phenyl-3-butenoic acid in tumorigenic cells
Authors: Burns Timothy J. , Matesic Diane F.
Published: June 2012

The c-Jun N-terminal kinase (JNK) signaling pathway controls many cellular processes such as cell growth, differentiation, and apoptosis. Aberrant JNK activity has been implicated in various cancer types including but not limited to hepatocellular carcinoma, glioblastoma, leukemia, and lung cancer, presumably through activation of the transcription factor activator protein-1 (AP-1). When activated by JNKs, AP-1 is a positive regulator of cell proliferation and many tumorigenic cell types are found to have increased JNK activity. Phosphorylated mitogen-activated protein kinase kinase 4 (pMKK4) and phosphorylated mitogen-activated protein kinase kinase 7 (pMKK7) are known to activate JNKs via phosphorylation. The purpose of this study was to determine the effects of 4-phenyl-3-butenoic acid (PBA) on JNK pathway proteins. PBA is a small molecule anti-inflammatory agent which was previously shown to inhibit growth, increase gap junction intercellular communication, and increase phosphorylation of p38 mitogen activated protein kinase (p38 MAPK) in tumorigenic cells at concentrations that do not similarly affect non-tumorigenic cells. Our studies utilized tumorigenic ras-transformed rat liver epithelial cells (WB-ras) and human lung carcinoma (H2009) cells. Cells were grown to confluence and were subjected to treatment with PBA (0.1 mg/ml) or vehicle for 48 hours. Whole cell lysates were extracted and individual proteins were separated by SDS-PAGE, followed by western blotting using phosphorylation site-specific antibodies to JNK pathway proteins. Quantitative analysis of western blots was performed utilizing densitometry software. PBA attenuated phosphorylation of JNK approximately two-fold in both WB-ras and H2009 lung carcinoma cells. PBA also attenuated phosphorylation of the JNK downstream effector, activating transcription factor 2 (ATF-2). Phosphorylation of MKK4 was decreased following treatment with PBA, while phosphorylation of MKK7 was unaffected. This data suggests that PBA may inhibit growth of tumorigenic cells in part through decreased activation of the JNK pathway via a MKK4 mechanism.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 2649. doi:10.1158/1538-7445.AM2011-2649
Abstract 2650: KRIBB801 modulates STAT3 pathway via binding to JAK3
Authors: Kwon Byoung-Mog , Shin Dae-Seop , Han Dong Cho
Published: June 2012

Constituent activation of STAT3 in human cancers causes abnormal proliferation and survival of cancer cell. Therefore, the small-molecules inhibiting STAT3 activity could be used for therapeutical drug in STAT3 dependent proliferating cancer cells. In this report, we screened small-molecules inhibiting STAT3 activity in chemical library containing 1,333 synthetic compounds obtained from “Korea Chemical Bank” through a cell-based luciferase assay system. KRIBB801 was selected as a novel inhibitor of STAT3 activation. KRIBB801 inhibits STAT3 phosphorylation at 1 hour and the expression of the STAT3-regulated genes at the same time point. Inhibition of STAT3 phosphorylation leads to apoptosis of MDA-MB-468. We postulated that inhibition of JAK family proteins or c-Src result in inhibition of STAT3 phosphorylation. Interestingly, phosphorylation of these kinases was mildly inhibited at 1 hr which phosphorylation of STAT3 was perfectly inhibitied. This result implies that inhibition of STAT3 phosphorylation by KRIBB801 is independent event with phosphorylation of upstream kinases. Co-immunoprecipitation shows that KRIBB101 inhibits the JAK3-STAT3 interaction. Moreover, JAK3 molecules were captured by biotylated KRIBB801. Finally, KRIBB801 inhibits kinase activity of JAK3 about 30% at 10 μM in vitro kinase assay. From these results, we suggest that KRIBB801 binds to JAK3 molecules and disturbs JAK3-STAT3 interaction which leads to inhibition of STAT3 phosphorylation.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 2650. doi:10.1158/1538-7445.AM2011-2650
Abstract 2652: Effect of selective serotonergic reuptake inhibitors on radiation therapy
Authors: Moran Nicci P. , Romano Michelle A. , Warren Graham W.
Published: June 2012

Introduction: Selective serotonergic reuptake inhibitors (SSRIs) are well-established antidepressants commonly used in cancer patients. Studies suggest that SSRIs may play a role in increased cell death in cancer cells; however, the use of SSRIs as adjunctive agents to be used in combination with conventional cancer treatment is not well established. The purpose of this study was to evaluate the effect of SSRIs on cell survival in combination with radiation therapy (XRT).

Methods: Human lung cancer lines (A-549 and H-460) and squamous oropharyngeal cancer cells (FaDu) were treated with several dose escalated SSRIs (fluoxetine, sertraline, paroxetine) alone or in combination with dose escalated XRT (0,2,4,6 Gy) to evaluate the cytotoxic effects of SSRIs using clonogenic survival assays. Western blot analysis was used to evaluate apoptosis (cleaved Caspase-3 and cleaved PARP) and autophagy (LC3-II) to assess potential mechanisms of the effects of SSRIs on XRT.

Results: Fluoxetine, paroxetine, or sertraline alone had a cytotoxic effect on cancer cells in a concentration dependent manner. Sertraline and paroxetine at 2.5-5uM appeared to have an additive effect on XRT with severe cytotoxicity noted at higher concentrations. In contrast, fluoxetine appeared to have a sensitizing effect on cells at 1-10uM in a tumor cell specific manor. Western blot analysis demonstrated that fluoxetine administration decreased cleaved Caspase-3 and cleaved PARP expression at 24 or 48 hours. Evaluation of autophagy using LC3-II demonstrated no change with XRT; however, treatment with fluoxetine increased the expression of LC3-II at 24 and 48 hours in the presence or absence of XRT.

Conclusions: Most SSRIs appear to have a cytotoxic effect alone or in combination with XRT. Fluoxetine appears to have a unique sensitizing effect on XRT in cancerous cells possibly through an increased induction of autophagy. Data supports further examination of fluoxetine as an adjunctive agent in combination with XRT.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 2652. doi:10.1158/1538-7445.AM2011-2652
Abstract 2654: 5-Fluorouracil increases and decreases proteins involved in oncogenic pathways
Authors: Wu Sherry Y. , Mori Noriko , Krishnamachary Balaji , Mironchik Yelena , Bhujwalla Zaver M.
Published: June 2012

Cancer cells are remarkably adaptive to treatments. 5-Fluorouracil, 5-FU, is a pyrimidine analogue, that is widely used for treatment of solid tumors1. It interferes with nucleoside metabolism and is incorporated into RNA and DNA, leading to cell death1. Its use, however, has been associated with increased cyclooxygenase-2 (COX-2) levels in breast, ovarian, esophageal, and colon cancers2 that could lead to the emergence of a more aggressive phenotype3. Here we have determined the effect of 5-FU in the expression of oncogenic molecules that are involved in phospholipid metabolism (choline kinase (Chk) and phospholipase D1 (PLD1)), inflammation (cyclooxygenase (COX)-2), and hypoxia response (hypoxia inducible factor (HIF)-1α) in order to facilitate a rational therapeutic design. Two triple negative breast cancer cell lines, MDA-MB-231 and SUM-149, were investigated. Cells were treated with 5-FU at various concentrations (1-25 μg/mL) and protein levels were examined at 24 and 48 hrs post treatment. Both HIF-1α and PLD1 levels decreased in a dose dependent manner following 5-FU treatment. In contrast, COX-2 level increased in response to 5-FU treatment together with an increase in Chk. Increased expressions of HIF-1α, PLD1, COX-2, and Chk have been associated with increased invasion and metastasis3-6. Our data suggest that in addition to its ability to interfere with DNA/RNA synthesis, 5-FU inhibits HIF-1α and PLD1 but increases the expression of two enzymes associated with invasive metastatic cancers. Importantly, while the mechanism by which 5-FU elevates COX-2 and Chk levels in these cancer cells remains to be investigated, these results provide a molecular basis for the combinational treatment of 5-FU with COX-2 and/or Chk inhibitors in cancer therapy.

References

(1) Arias J. Molecules, 2008.

(2) Mercer S.J., et al. Anticancer Drugs, 2005.

(3) Stasinopoulos I, et al. Neoplasia, 2008.

(4) Pai J.K., et al. Anticancer Drug Des, 1994.

(5) Shah T., et al. NMR Biomed, 2010.

(6) Lu X and Kang Y. Clin Cancer Res, 2010

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 2654. doi:10.1158/1538-7445.AM2011-2654
Abstract 2655: Visualization of G1 arrest of cell cycle induced by inhibition of PI-3 kinase in cancer cells: in vitro evaluations
Authors: Mukai Yumiko , Dan Shingo , Okamura Mutsumi , Inoue Yasumichi , Hanyu Aki , Sakaue-Sawano Asako , Imamura Takeshi , Miyawaki Atsushi , Yamori Takao
Published: June 2012

The phosphoinositide 3-kinase (PI3K) pathway is frequently activated in cancer, and is considered as a promising therapeutic target of cancer therapy. Since PI3K pathway mediates growth- and anti-apoptotic signals, inhibition of PI3K is expected to induce apoptosis and/or growth arrest in cancer cells. We previously developed Fluorescent Ubiquitination-based Cell Cycle Indicator (Fucci) system to enable real-time visualization of cell cycle progression in live cells. Taking advantage of Fucci system, we examined cell cycle progression after treatment of various PI3K inhibitors by using a time-lapse fluorescent microscope. As a result, we could visualize the induction of G1 arrest of cell cycle in breast cancer MCF-7 cells within 24 h after treatment with ZSTK474, and the G1 arrest lasted at least 48 h. Similar results were obtained after treatment with other PI3K inhibitors such as NVP-BEZ235 and GDC-0941. These results clearly indicate that PI3K inhibitors exert antitumor activity via a cytostatic mechanism by inducing G1 arrest of cell cycle.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 2655. doi:10.1158/1538-7445.AM2011-2655
Abstract 2660: Downregulation of Bora gene expression in human tumor cells results in radioresistance by promoting repair of double strand breaks
Authors: Hou Junmei , Qin Bo , Lou Zhenkun , Wang Liewei
Published: June 2012

DNA double-strand breaks (DSBs) are highly cytotoxic lesions caused by genotoxin such as ionizing radiation (IR). Following DSB, cells activate the DNA-damage response pathway by activating protein kinases such as ATM, ATR and DNA-PK, which then trigger histone H2AX phosphorylation and the accumulation of proteins such as Mediator of DNA damage checkpoint protein 1 (MDC1), 53BP1, and BRCA1 into IR-induced foci. This process initiates the repair of DSB. Previously we have identified a novel biomarker for radiation response, Bora, by using a genome-wide association approach using data generated with 300 human lymphoblastoid cell liens. Bora is known as a cofactor of Aurora-A, which is involved in mitosis regulation. During G2, Aurora-A, in complex with Bora, phosphorylates Plk1 at Thr-210. Activated Plk1 phosphorylates Cdc25C and Wee1, which induces activation of cyclin B-cdk1 complexes and promotes mitotic entry. In this study, we want to determine the underlying mechanisms by which Bora regulates response to IR. We found that knockdown of Bora in human cancer cell lines including HupT3, MIAPaCa-2 and Hela (siBora) exhibit increased clonogenic survival rate in response to IR, an observation that is opposite from the effect of Plk1 knockdown, suggesting a different mechanism involved. Knockdown of Bora also desensitize cancer cells to chemotherapeutic agents including gemcitabine and oxiplatin. This enhanced resistance to genotoxin is primarily due to increased DNA DSB repair. More than 90% of DSBs were repaired in siBora cells compared with 60% in control cells 8 hours after cell exposure to 2 Gy IR. Upon IR, more cells with Bora knockdown retained in G2-M phase compared with control. Furthermore, Bora directly interacts with BRCT domain of MDC1 via its C terminus, and over expression of Bora can abolish MDC1 foci formation induced by IR. All of these observations suggested a role of Bora in DNA damage response pathway and in turn, in chemo-radio resistance. Indeed, overexpression of the full length or C-terminus of Bora sensitized cancer cells to IR treatment, while the N-terminal Bora did not have significant effect on IR response. In summary, we have identified a novel function of Bora involved in DNA damage and repair pathway, which indicates a broad role of Bora in both tumorgenesis and chemo-radio resistance.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 2660. doi:10.1158/1538-7445.AM2011-2660
Abstract 2678: Effect of amentoflavone on radiation response in neuronal cells
Authors: Wang Yi , Kong Xiangjuan , Tang Xiaobing , Zheng Xiaoke , Zhu Yanhui , Wang Shengqi , Wang Shengqi , Wang Huichen
Published: June 2012

Ionizing radiation induces DNA damage and oxidative stress, leading cell death during cancer therapy or genomic instability and carcinogenesis amentoflavone is a purified component extracted from medicine plants that are used to treat various diseases. Here we investigated the role of amentoflavone in radiation response in hippocampal neurons (HT22) and glioblastoma cells (U87 MG) following exposure to high linear transfer (LET) radiation and low LET radiation We found that Amentoflavone protects hippocampal neurons from radiation and enhances radiosensitivity of glioblastoma cells.Treatment of amentoflavone increased survival fractions in hippocampal neuronal cells following exposure to X-Ray radiation and 56Fe particles, though amentoflavone enhanced radiosensitivity of glioblastoma cells. Amentoflavone attenuated reactive oxygen species (ROS) and regulated DNA damage repair in irradiated hippocampal neurons through superoxide dismutase 1 (SOD1) and Foxkhead box O3 a (FOXO3a) pathways. Pretreament of amentoflavone also increased the survival rate of mice from whole body gamma irradiation. This suggests that amentoflavone may have a potential function on cancer chemo- radiotherapy and radiation protection from cancer risks. The mechanism needs to be further studied.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 2678. doi:10.1158/1538-7445.AM2011-2678
Abstract 2681: Identification of potential immunologic targets found in mice and man that are expressed in colon adenomas and colorectal cancer
Authors: Broussard Elizabeth K. , Pritchard David K. , Lubet Ronald A. , Disis Mary L.
Published: June 2012

Multiple recent studies have demonstrated that colorectal cancer (CRC) is immunogenic and that host adaptive immunity may play a role in inhibiting disease relapse. We have shown that overexpressed tumor associated proteins, those abundant in the cancer state but expressed at basal levels normal cells, can be immunogenic. The purpose of this study was to identify genes overexpressed in colorectal adenoma that maintain upregulation in CRC using publicly available microarray datasets in the Gene Expression Omnibus. Such genes may encode proteins that could be suitable as immunologic targets for a colon cancer vaccine. We identified 7 high-quality datasets (GSE 867, 4183, 1095, 5206, 15960) where human adenomatous or CRC tissue was directly compared to normal colon. Inclusion criteria for the datasets included: commercial platforms, primary tissue, normal colon expression included, data generated after 2005, and access to microarray data. We reanalyzed these datasets and identified 100 genes that were ≥ 2-fold up-regulated in both adenomas and CRC, relative to normal colon. We further characterized these genes using a scoring system using the following criteria: 1) strong expression in CRC as compared to normal colon (RNA and protein), 2) evidence that the gene is biologically important in CRC initiation or progression, 3) limited expression of the gene in normal tissues, and 4) proven immunogenicity of the encoded protein. We hypothesized that genes that were highly conserved across species would potentially have greater biologic relevance, so we identified relevant microarray studies in mouse CRC models. We identified 2 studies (GSE 422, 784) which were limited in their data set and performed a similar analysis. We identified 93 murine genes that were conserved from adenoma to carcinoma. Comparison of the human and rodent data set revealed an overlap of 11 genes. We conclude that there are a limited number of genes up-regulated in adenoma and carcinoma and conserved across disease in mouse and man. If these proteins are immunogenic, they may serve as novel immunologic targets to prevent the progression from normal colonic epithelium to adenoma or carcinoma.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 2681. doi:10.1158/1538-7445.AM2011-2681
Abstract 2687: Immunopotentiator, protein-bound polysaccharide K, is efficient for advanced gastric cancer with negative expression of MHC Class I
Authors: Gentaro Ito , Hiroaki Tanaka , Mami Yoshi , Takehiro Iwauchi , Kazuya Muguruma , Naoshi Kubo, , Hisashi Nagahara , Kenjiro Kimura , Ryosuke Amano , Eiji Noda , Nobuya Yamada , Masakazu Yashiro , Naoyoshi Onoda , Kiyoshi Maeda , Bunzo Nakata , Masaichi Ohira , Tetsuro Ishikawa , Kosei Hirakawa
Published: June 2012

It has been reported that down-regulation of MHC class I in cancer cells was associated with poor prognosis of gastrointestinal cancer, because of immunological escape from the attack of antigen specific cytotoxic T lymphocytes. Protein-bound polysaccharide K (PSK), nonspecific immunopotentiator, is approved for adjuvant chemotherapy against Stage II/III gastric cancer in Japan. Several randomized studies have demonstrated the efficacy of immunochemotherapy using PSK for colon and gastric cancer. The aim of this study was to investigate whether expression of MHC class I was associated with prognosis of the patients who received PSK as postoperative adjuvant therapy. We retrospectively analyzed total of 349 gastric cancer patients who underwent curative gastric cancer surgery in Department of Surgical Oncology, Osaka City University from 1995 to 2008. We investigated the expression of MHC class I antigen in primary lesions using immunohistchemistry to compare the relapse-free survival (RFS) between the patients receiving only oral fluoropyrimidine agents (the control group) and plus PSK (the PSK group). 124 patients were assigned to the PSK group and 225 patients to the control group. There were no differences between two groups in background factors. In analysis of MHC class I expression, 193 patients were classified as MHC class I positive, and 156 patients as MHC class I negative. RFS was significantly better in MHC class I positive group. Combination of anti cancer agents with PSK did not improve the RFS among total patients. However, in patients with multiple lymph node metastasis and negative expression of MHC class I, the 5-year RFS of the PSK group was significantly better than the control group. These results suggested that the expression of MHC Class I in primary lesion could be one of the prognostic markers related to the efficiency of adjuvant immunochemotherapy for patients with gastric cancer.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 2687. doi:10.1158/1538-7445.AM2011-2687
Abstract 269: DACH1 (Dachshund homolog 1) attenuates forkhead signaling through recruiting transcription elongation regulator 1 (TCERG1)
Authors: Wang Chenguang , Zhou Jie , Wu Kongming , Tozeren Aydin , Zhao Keji , Pestell Richard G.
Published: June 2012

The Drosophila Dachshund (Dac) gene, cloned as a dominant inhibitor of the hyperactive growth factor mutant, ellipse, encodes a key component of the Retinal Determination Gene Network (RDGN) that governs cell fate. DACH1 (Dachshund homolog 1) regulates gene expression either indirectly as a co-integrator or through direct DNA binding. CAST identified a DACH1 DNA-binding sequence which resembles the FOX (Forkhead Box containing protein) binding site. Genome-wide in-silico promoter analysis of DACH1 binding sites identified gene clusters populating cellular pathways associated with the cell cycle and growth factor signaling. ChIP-Seq mapped DACH1 binding sites to corresponding gene clusters predicted in silico and identified as weight matrix resembling the CAST-defined sequence. DACH1 antagonized FOXM1 target gene expression, promoter occupancy in the context of local chromatin, and contact-independent growth. Further studies were conducted to understand, at a higher level of resolution, the mechanisms governing DACH1-mediated transcriptional repression via DNA-sequence specific binding. DACH1 repressed, while FOX proteins enhanced, both DRE and FOXA responsive element-driven gene expression. Reduced DACH1 expression using a shRNA approach enhanced FOX protein activity. As DACH1 antagonized FOX target gene expression and attenuated FOX signaling, we sought to identify limiting co-integrator proteins governing DACH1 signaling. Proteomic analysis identified transcription elongation regulator 1 (TCERG1) as the transcriptional co-regulator of DACH1 activity. The FF2 domain of TCERG1 was required for DACH1 binding, and the deletion of FF2 abolished DACH1 trans-repression function. The carboxyl terminus of DACH1 was necessary and sufficient for TCERG1 binding. Thus, DACH1 represses gene transcription through direct DNA binding to the promoter region of target genes by recruiting the transcriptional co-regulator, TCERG1. Attenuation of FOX function by the cell fate determination pathway has broad implications given the diverse role of FOX proteins in cellular biology and tumorigenesis.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 269. doi:10.1158/1538-7445.AM2011-269
Abstract 2695: Lactobacillus plantarum induces TRAIL production and facilitates natural killer activity against cancer cells
Authors: Horinaka Mano , Yoshida Tatsushi , Kishi Atsuko , Akatani Kaoru , Yasuda Takashi , Kouhara Junji , Wakada Miki , Sakai Toshiyuki
Published: June 2012

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is a promising anti-tumor agent due to its induction of apoptosis in various types of malignant tumor cells with little or no toxicity in normal cells. TRAIL is an endogeneous cytokine, and thus, it may be possible to develop agents that can induce endogeneous TRAIL production as an anti-tumor strategy. Here, we show for the first time that lactobacilli induce TRAIL production in normal human peripheral blood mononuclear cells (PBMC). Treatment with heat-killed Lactobacillus (L.) plantarum, a type of lactobacilli, induced TRAIL expression on the surface of PBMC. L. plantarum also enhanced the release of soluble TRAIL into the culture medium. Moreover, L. plantarum increased the level of TRAIL mRNA as well as TRAIL protein, indicating that L. plantarum up-regulates TRAIL gene expression. L. plantarum also increased the secretion of interferon-γ (IFN-γ) from PBMC. The release of soluble TRAIL from PBMC was partially blocked by IFN-γ neutralization antibody, indicating that the TRAIL production induced by L. plantarum at least partially depends on IFN-γ. To examine whether TRAIL production by L. plantarum leads to cytotoxicity in cancer cells, we co-cultured prostate cancer cells with L. plantarum-treated PBMC and measured natural killer (NK) activity. L. plantarum facilitated NK activity, and the dominant negative form of TRAIL receptor and TRAIL neutralization antibody efficiently prevented NK activity. Our results indicate that L. plantarum facilitates TRAIL-dependent NK activity through TRAIL production, and raise the possibility of a new strategy for TRAIL-based prevention or therapy against malignant tumors.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 2695. doi:10.1158/1538-7445.AM2011-2695
Abstract 2705: Glycoprotein 90K's antitumor effects through activation of the dendritic cells
Authors: Lee Ji Hee , Park Myong Suk , Park Mi Ra , Bae Woo Kyun , Hwang Jun Eul , Lee Jae Hyuk , Chung Ik Joo
Published: June 2012

The secreted glycoprotein, 90K is also known as Mac-2 binding protein belonging to the scavenger receptor cysteine-rich domain superfamily that is implicated in immune defense and immune regulation. We examined the relation between over-expressed 90K in tumor cells and immune activation.

Here, we investigated whether over-expressed 90K enable the activation of signal transduction pathways and subsequent modulation of DC-maturation status. In vitro cell functional assay, transduction of 90K to dendritic cells was achieved by adenoviral system. Also, we tried to make a mouse model with cancer overexpressing 90K and cancer knockdowned 90K. Then, we analyzed the infiltrated immune cell into tumor region and splenocytes of tumor bearing mice. Dendritic cells transfected with 90K showed IL12p70 and IFN-gamma incensement in DC-cytokine profile and induction of Th1 responses. Tumor infiltrating cells (TIL) into splenocytes were increased in tumor bearing mice knockdowned 90K. Our data indicate that 90K can induce robust maturation of dendritic cells and tumor regression through recruiting TIL. We suggest that 90K may play role in a new target for the treatment of cancer by immune modulation.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 2705. doi:10.1158/1538-7445.AM2011-2705
Abstract 271: Rapid regulation of ion channel KCNK5 by ERα in breast cancer cell lines MCF-7 and T47D promotes cell proliferation
Authors: Alvarez-Baron Claudia P. , Jonsson Philip , Dryer Stuart , Williams Cecilia
Published: June 2012

Many human breast tumors rely on the proliferative effect of estrogen to propagate. Estrogenic compounds, such as the endogenous ligand 17β-estradiol, signals in various manners, most prominently through the estrogen receptors (ERs). The ERs – alpha and beta, respectively – are transcription factors belonging to the superfamily of nuclear receptors. They act by genomical and non-genomical mechanisms in a ligand-dependent as well as -independent manner, exerting ligand-, promoter- and tissue-specific transcriptional programs. Due to the proliferative effect of ERα in breast it is an important factor in tumor progression. ERα is used clinically as a biomarker and is therapeutically targeted by treatment with antagonistic compounds, for instance tamoxifen. Although extensively studied, the mechanism by which ERα promotes proliferation remains to be fully established. Here we present the finding that ERα rapidly upregulates the potassium ion channel KCNK5 (TASK-2, K2P5.1) in human breast cancer cell lines MCF-7 and T47D. ERα binds at the enhancer of the KCNK5 gene upon estrogen stimulation, subsequently inducing increases in transcript and protein levels of KCNK5. The observed upregulation was strikingly quick, with a sharp peak within one to two hours, before leveling off. Protein levels, however, did not increase until after 12 hours. Treatment with compounds antagonizing ERα transactivation efficiently suppressed this upregulation, further supporting the notion of direct ERα regulation, as compared to non-genomic signaling. Estrogen treatment also increased KCNK5 currents in both cell lines. Various roles for potassium channels in cancer cells have previously been suggested, as for example proliferative, metastatic and anti-apoptotic factors. Knockdown of KCNK5 by siRNA in MCF-7 and T47D cells decreased their proliferation. Additionally, in T47D cells, the estrogen-induced proliferation was repressed when KCNK5 was silenced. This prompts further studies to understand the role of KCNK5 in the proliferation of breast cancer cells and clinical relevance.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 271. doi:10.1158/1538-7445.AM2011-271
Abstract 2710: KSHV-induced PDGF signaling dyregulation drives a Rac1 and ROS-mediated paracrine tumorigenic mechanism necessary for Kaposi's sarcoma
Authors: Cavallin Lucas E. , Ma Qi , Goldschmidt-Clermont Pascal J. , Mesri Enrique A.
Published: June 2012

Kaposi's sarcoma (KS), caused by the Kaposi's sarcoma-associated herpesvirus (KSHV), is a major AIDS-associated malignancy characterized by angiogenesis and proliferation of spindle cells. KSHV-infected KS lesions are composed of latently-infected cells and a minority of cells expressing lytic genes such as vGPCR, which are implicated the development of KS angioproliferative phenotype via a paracrine mechanism. A key unsolved question is how this minor population of lytically-infected cells expressing vGPCR transduce an angio-proliferative phenotype to latently-infected cells. Here, we describe a Rac1 and ROS driven mechanism of paracrine amplification of viral oncogenesis in the KSHV-induced tumor model mECK36. It is triggered by vGPCR-induced PDGF secretion, which in the presence of high expression of PDGF receptors and NADPH oxidase family members caused by latent KSHV infection, leads to STAT3-mediated transcriptional activation of c-Myc, VEGF and KSHV latent genes. This paracrine loop, driven by PDGF signaling and regulated by Rac1 and ROS, amplifies vGPCR oncogenesis by driving proliferation and angiogenesis in latently-infected cells. Inhibtion of this molecular pathway by either the antioxidant N-acetylcysteine (NAC) or PDGF receptor tyrosine kinase inhibitors impair KSHV-induced tumorigenesis, angiogenesis and lymphangiogenesis, further validating this paracrine oncogenesis mechanism and its components as anti-KS tumor targets.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 2710. doi:10.1158/1538-7445.AM2011-2710