bluuebunny/crossref_metadata_2025_split huggingface dataset:
Abstract 2463: Side population cells have some stem-like properties in hepatocellular carcinoma
Authors: okabe Hirohisa , Beppu Toru , Ishiko Takatoshi , Chikamoto Akira , Masuda Toshiro , Otao Ryu , Hasita Horlad , Mima Kosuke , Takamori Hiroshi , Baba Hideo 
Published: June 2012

Abstract
Background: There are many problems to be solved in cancer stem cells (CSCs) in digestive organs. Liver cancer stem cells also have a major problem that we have to determine the cancer stem cell markers and clarify the function of CSCs. In this study, we tried to validate CSC markers that are previously reported using side population (SP) cells in hepatocellular carcinoma cell lines.
Methods: Side population cells in seven hepatocellular carcinoma (HCC) cell lines (PLC/PRF/5, HuH1, HuH7, HLE, HepG2, HLF, and SK-Hep1) were analyzed using Flow cytometry (FACS AriaII). The differences between SP cells and Non-SP cells in several markers relating to epithelial-mesenchymal transition and in several liver CSC markers were investigated using quantitative RT-PCR. The difference about intracellular signals between them was also studied using Western blot analysis. Using HuH7 cell, the ability of spheroid formation of SP cells and the difference between spheroid forming cells and 2-dimensional cultured cells were investigated.
Results: The range of percentage of SP cells was from 0 % to 4.1 %. We sorted SP cells from four HCC cell lines (PLC/PRF/5, HuH1, HuH7, and HLE). There were no remarkable difference of CDH1 and vimentin between SP cells and Non-SP cells. Previously reported liver cancer stem cell markers such as EpCAM, CD90, and CD44 were significantly increased in SP cells. However, the expression of CD133 and Bmi1 in SP cells was unexpectedly decreased or similar to non-SP cells. The ability of spheroid formation of SP cells was significantly higher than that of non-SP cells. Spheroid forming cells showed remarkably higher expression of EpCAM, CD90, and CD44 than 2-dimensional cultured cells. These were considered to be important markers regulating CSCs. The expression of cell cycle marker MIB1 in the SP cells was remarkably decreased compared to that of non-SP cells. This fact supports to the theory that normal or cancer stem cells maintain their cell cycle arrest. SP cells maintained specific signals activated such as sonic hedgehog and MAPK signals.
Conclusions: Liver cancer stem cell markers such as EpCAM, CD90, and CD44 were considered to be important for the maintenance of SP cells in hepatocellular carcinoma. The activation of specific intracellular signals was also seen in SP cells. We are now challenging to confirm the importance of those signals using HCC cells extracted from human liver tissues. The current study may be help of understanding the regulation of liver cancer stem cells.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 2463. doi:10.1158/1538-7445.AM2011-2463
Abstract 2482: Bat3 facilitates histone H3 lysine 79 dimethylation by DOT1L to promote ionizing radiation-induced 53BP1 foci formation during G1- and G2-phases of the cell cycle
Authors: Wakeman Timothy P. , Feng Junjie , Wang Xiao-fan 
Published: June 2012

Abstract
DOT1L is a unique histone methyltransferase involved in normal cellular metabolism and in the initiation of certain leukemias. DOT1L specifically methylates histone H3 at K79, promoting the interaction of H3 with various binding partners. 53BP1, a component of the DNA damage response machinery, has been shown to interact with H3 K79-diMe following exposure to ionizing radiation; however, it remains unclear if this modification is required for 53BP1 foci formation as 53BP1 interacts with histone H4 K20-diMe with a much higher efficiency. Here, we clarify the role of H3 K79-diMe by demonstrating that this modification contributes to IR-induced 53BP1 foci formation during G1- and G2-phases of the cell cycle, but is negligible during S-phase. Further, we describe an essential role for HLA-B-associated transcript 3 (Bat3) in regulating this process. Bat3 co-localizes with DOT1L at histone H3, and Bat3 knockdown results in decreased DOT1L-H3 interaction and H3 K79-diMe, leading to a reduction in IR-induced 53BP1 foci formation. Bat3-depleted cells also exhibit defects in DNA repair and increased sensitivity to IR. We demonstrate that a conserved ubiquitin-like motif of Bat3 and a conserved DOT1L ubiquitin interacting motif are required for DOT1L-Bat3 interaction, which promotes efficient H3 K79-diMe and IR-induced 53BP1 foci formation. Taken together, our data identify a novel role for Bat3 in regulating DOT1L function.
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 2482. doi:10.1158/1538-7445.AM2011-2482
Abstract 2483: Molecular mechanisms underlying chemopreventive activities of glycyrrhizic acid against UVB-induced carcinogenesis in SKH-1 hairless mouse epidermis
Authors: Cherng Jaw-Ming , Tsai Kuen-Daw , Wei James C. , Perng Daw-Shyong , Yu Alice Y. , Lin Jung-Chung 
Published: June 2012

Abstract
Glycyrrhizic acid (GL) has been shown to possess anti-inflammation, antiviral, and chemoprotective activity against tumors. We assessed the protective effects of GL in UVB-induced skin tumor formation in SKH-1 hairless mice and the early molecular biomarkers. Mice irradiated at 180 mJ/cm2 twice per week elicited 100% tumor incidence in 20 weeks. Feeding of GL prior to UVB irradiation caused a strong protection against photocarcinogenesis in terms of delay in tumor appearance, multiplicity, and size. It took 24 weeks to get 100% tumor incidence in GL plus UVB treated-group; the first tumor appearance in UVB-treated animals occurred at 16th week, which was delayed by 3 weeks in GL plus UVB-treated group. Feeding of GL for 2 weeks before a single UVB (180mJ/cm2) irradiation resulted in a strong and significant decrease in UVB-induced thymine dimer-positive cells (p &lt; 0.004), proliferative cell nuclear antigen PCNA (p &lt; 0.01), terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling, and apoptotic sunburn cells (p &lt; 0.01) together with an increase in p53 and p21/Cip1-positive cell population in epidermis (p &lt; 0.02 ∼ 0.003). Simultaneously, GL also significantly inhibited NF-κB, cyclooxygenase-2 (COX-2), prostaglandin E2 (PGE2), and nitric oxide (NO) levels (p &lt; 0.01-0.004). Taken together, these results suggest that GL causes a strong protective effect against photocarcinogenesis via down-regulation of cell proliferative controls, involving thymine dimer, PCNA, apoptosis, transcription factors NF-kB and of inflammatory responses involving COX-2, PGE2, and NO, while up-regulation of p53, p21/Cip1 to prevent DNA damage. These results provide a focus for the rational development of GL as a novel chemopreventive agent against UV-induced human skin 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 2483. doi:10.1158/1538-7445.AM2011-2483
Abstract 2487: A multi-kinase inhibitor, XL228, enhanced human cancer cell radiosensitivity and suppressed cell invasion and migration
Authors: Matsumoto Fumihiko , Molkentine David , Clary Douglas O. , Milas Luka , Ang Kian K. , Raju Uma 
Published: June 2012

Abstract
Purpose:, Targeting signaling pathways that are implicated in cancer cell resistance to therapy is being investigated to improve outcome. XL228 is a small molecule inhibitor of IGF-1R, cSrc, BCR/Abl and aurora kinases, which are frequently overexpressed or hyperactive in many cancer types including head and neck squamous cell carcinomas (HNSCCs) and non small cell lung cancers (NSCLCs). This study investigated the potential of XL228 in enhancing cancer cell sensitivity to radiation.
Materials and Methods: Three HNSCC (HN-5, FaDu and UMSCC-1) and three NSCLC lines (H460, A549 and H1299) were used for this in vitro study. Cell viability assay was used to assess the single agent activity of 5-100 nM of XL228 for 1-3 d. In addition, the effects of XL228 (10 or 100 nM) on apoptosis (TUNEL assay), and cell cycle redistribution (flow cytometry), migration and invasion were evaluated. Clonogenic cell survival assayed (in HN-5, FaDu, A549 and H460) after exposing the cells to graded doses of γ-radiation, with or without XL228 (10, 50 or 100 nM) was used to quantify the effect on radiosensitivity.
Results: XL228, at 5-100 nM, reduced survival of all cell lines tested by 10-70% in a dose and time dependent manner and inhibited migration and invasion of two tumors with high propensity to metastasize, FaDu and H460. At 50 and 100 nM XL228 abolished the ability of H460, A549 and FaDu cells to form colony. At 10 nM XL228 significantly increased the radiosensitivity of H460, A549 and FaDu cells by enhancement factors (EF, at the survival fraction of 0.5) of 1.52, 1.31 and 1.67 respectively. But, sensitization of HN-5 cells occurred only at 100 nM (EF = 2.27). Flow cytometry analysis showed that 10 nM of XL228 (that enhanced radiosensitivity of three cell lines) had no effect on the cell cycle distribution and it did not induce apoptosis tested at 24 h after exposure to XL228. However, in HN-5 cells 100 nM of XL228 induced accumulation of cells at the radiation sensitive G2/M phase of the cell cycle and induced apoptosis in 32% of cells. Mechanistic studies including inhibition of DNA repair processes are ongoing.
Conclusions: This study demonstrated that XL228 as a single agent reduced viability, inhibited proliferation, migration and invasion of cells. In combination with radiation, XL228 enhanced HNSCC and NSCLC radiosensitivity. The underlying processes leading to enhanced radiosensitivity may be cell type specific. These data warrant in vivo investigations aiming at taking best regimens to the clinic testing.
(XL228 was provided by Exelixis, Inc. South San Francisco, CA.
Supported by P0-1 CA-06294)
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 2487. doi:10.1158/1538-7445.AM2011-2487
Abstract 249: Inhibition of protein phosphatase 2A supports androgen-independent growth of prostate cancer cells
Authors: Bhardwaj Arun , Singh Seema , Srivastava Sanjeev K. , Honkanen Richard E. , Reed Eddie , Singh Ajay P. 
Published: June 2012

Abstract
Clinical progression of prostate cancer (PCa) is characterized by a transition from androgen-dependent (AD) to androgen-independent (AI) stage. Once the PCa has recurred in AI form, it progresses to a highly aggressive disease and poses an increased risk of morbidity and death. Therefore, understanding the mechanisms involved in AI progression of PCa is a significant area of research. Earlier, we identified PPP2CA, which encodes for alpha-isoform of the protein phosphatase 2A catalytic subunit (PP2Acα), as one of the downregulated genes in AI PCa cells. PP2A is a ser/thr phosphatase and a potent tumor suppressor involved in broad cellular functions; however, its role in PCa has not yet been determined. Here, we have investigated the effect of PP2A downregulation on the growth of AD PCa (LNCaP) cells under steroid-deprived condition. Furthermore, we have examined the effect of PP2A inhibition on the signaling pathways and delineated their role in AI growth of LNCaP cells. Our data show that the downregulation of PP2A activity by pharmacological inhibition or siRNA-mediated PPP2CA silencing sustains the growth of AD PCa cells under androgen-deprived condition by relieving the androgen-deprivation-induced cell cycle arrest and preventing apoptosis. Immunoblot analysis revealed enhanced phosphorylation of Akt, ERK, BAD, increased expression of cyclins (cyclin A1 and cyclin D1) and decreased expression of cyclin inhibitor (p27) upon PP2A downregulation. Furthermore, our data show that PP2A inhibition partially maintains AR signaling through its increased expression and ligand-independent phosphorylation, which is also supported by AR transcriptional activity assay and its target gene, KLK3, expression. Pharmacological inhibition of Akt, ERK and AR confirmed a role of these signaling pathways in facilitating the AI growth of LNCaP cells. Altogether, our findings suggest that modulation of PP2A activity may represent an alternative therapeutic approach for the treatment of advanced androgen-independent prostate 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 249. doi:10.1158/1538-7445.AM2011-249
Abstract 2496: Inhibition of IL-6 signaling induces radiosensitivity in head and neck squamous cell carcinoma (HNSCC)
Authors: Skinner Heath D. , Su Ying-Wen , Ow Thomas J. , Myers Jeffery 
Published: June 2012

Abstract
Squamous cell carcinoma of the head and neck (HNSCC) is the sixth most common cancer worldwide. One of the primary modalities used to treat HNSCC is external radiotherapy, however many tumors are resistant to this treatment. Several studies have noted increased expression of IL-6 and IL-6 receptor in a variety of tumors. Furthermore, inhibition of IL-6 using a monoclonal antibody, tocilizumab, as a monotherapy has been shown to decrease tumor growth of HNSCC in pre-clinical models. However the effect of IL-6 signaling on radiosensitivity has not been well characterized. In this study we have found that baseline radioresistance, determined using a standard clonogenic assay, was significantly higher in HNSCC cell lines expressing high levels of IL-6 receptor (IL-6R) compared to those expressing low levels or IL6R as measured by RT-PCR (Surviving fraction at 2Gy (SF2) 65%% vs. 45%, p=0.028). In HN 31 and PCI 15B cell lines, which express high levels of IL-6 receptor, the addition of tocilizumab potentiated radiosensitivity, with a decrease in SF2 of 15% (p&lt;0.05) in both cell lines. This finding was not observed in normal human fibroblasts. Also, the addition of tocilizumab inhibited radiation-induced survival signaling in a dose dependent fashion. Finally, we used immunohistochemistry to show that clinical samples of HNSCC from a variety of sites express IL-6 receptor, compared to little to no staining in surrounding normal tissue. Thus, the addition of tocilizumab to radiotherapy has the potential to enhance the radiosensitivity of HNSCC while minimizing the effect on normal tissue.
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 2496. doi:10.1158/1538-7445.AM2011-2496
Abstract 2498: Resveratrol administration increases SOD2 and reduces oxidative stress to DNA
Authors: Miller Richard C. , Murley Jeffrey S. , Baker Kenneth L. , Miller Kristin L. , Sullivan Joseph T. , Wardak Hamid , Murley Tyler S. , Grdina David J. 
Published: June 2012

Abstract
Mitochondrial manganese superoxide dismutase (SOD2) activation is a downstream product after stimulation via a variety of signaling pathways from a diversity stimulating agents. Thiols including amifostine (S-2-[3-aminopropylamino]ethylphosphorothioic acid) mesna (sodium-2-mercaptoethanesulfonate), NAC (N-acetyl-L-cysteine) and captopril ([S]-1-[3-mercapto-2-methyl-1-oxo-propyl]-L-proline), are effective inducers of SOD2. Non-thiols including estrogen, cerium oxide, low doses of x-rays, and resveratrol (3,4’,5-trihydroxystilbene) have been shown to induce SOD2 under specific treatment conditions. Studies with resveratrol typically involve continuous exposure of cells for several days before determining the effectiveness of the agent as a radioprotector. In studies reported here, SA-NH murine sarcoma tumor cells established for growth in culture were exposed to a single dose of 50μM resveratrol and analyzed for SOD2 activity from 2hr to 28hr post exposure. Early indications suggest that cells induce SOD2 earlier than typically seen for thiols and other oxidative stress modifiers. Resveratrol increases levels of SOD2 by a factor of 3 compared to controls which is similar to levels observed with thiol exposure. While thiols induce SOD2 via the NFκB pathway, resveratrol acts through the FOXO3a pathway. Studies continue to examine SOD2 activity after exposure to acute exposures resveratrol, amifostine, and x-rays.
This work was supported by DOE grant DE-SC0001271 (D.J.G.) and NIH grant RO1-CA132998 (D.J.G.).
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 2498. doi:10.1158/1538-7445.AM2011-2498
Abstract 2499: Sulfasalazine sensitizes glioblastoma cells to radiation treatment
Authors: Sleire Linda , Wang Jian , Heggdal Jan , Pedersen Paal-Henning , Enger Per Øyvind 
Published: June 2012

Abstract
Glioblastomas (GBMs) are lethal cancers with a limited response to ionizing radiation. Recent studies suggest that Sulfasalazine (SAS), a drug used to treat inflammatory bowel disease, inhibits the xCT antiporter system in glioma cells, thereby blocking their uptake of cystein. Since the availability of cystein is a rate limiting step in intracellular antioxidant production, we wanted to investigate whether sulfasalazine sensitizes glioma cells to radiation.
SAS effect on glioma cell growth was investigated using an electric cell substrate impedance sensing (ECIS) instrument. All cell lines showed altered growth curves in response to SAS treatment. To assess the effect of blocking the xCT antiporter, intracellular levels of the antioxidant glutathione were measured. With increasing doses of SAS, glutathione levels decreased in a dose response manner. Further, U251 glioma cells were treated with escalating doses of SAS, alone or in combination with radiation (8 Gy). Nuclear integrity was evaluated to estimate cell death following treatment. In addition, cell death and viability were investigated using live/dead staining and MTS assay respectively.
All treatment groups exhibited increased rates of cell death compared to untreated controls. However, a combination of SAS and radiation resulted in higher levels of cell death, than radiation or SAS administered alone. In order to assess whether this can be exploited therapeutically, we are currently preparing to treat nude rats harbouring gliblastoma biopsy xenografts with SAS, alone or in combination with radiation.
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 2499. doi:10.1158/1538-7445.AM2011-2499
Abstract 252: Evaluating the role of STK33 kinase in mutant KRAS cells
Authors: Babij Carol , Shehabeldin Amro , Fernando Manory , Quon Kim , Kassner Paul , Ruefli-Brasse Astrid , Watson Vivienne , Fajardo Flordeliza , Zhang Yihong , Zondlo James , Sun Yu , Ellison Aaron R. , Plewa Cherylene , Dussault Isabelle , Carnahan Josette 
Published: June 2012

Abstract
Tumors harboring KRAS mutations remain an elusive target for oncology therapeutics. A recent publication (Scholl et al 2009) described a high throughput cellular RNAi screen which suggested a synthetic lethal relationship between STK33 and mutant KRAS. STK33 is a member of the calcium/calmodulin kinase family with a poorly characterized function. Although no genetic alterations in the STK33 gene have been reported in cancer, inhibiting STK33 kinase activity could offer a novel therapeutic approach to target mutant KRAS tumors. Thus, we sought to validate whether the survival of cancer cell lines with mutant KRAS is dependent on STK33, in parallel with a program to identify small molecule inhibitors of STK33 (Zhang Y et al AACR 2011). We focused on mutant KRAS leukemia cells because of their reported dependence on STK33. Using a panel of siRNA, 50-80% knockdown of STK33 at the RNA and protein level was achieved in NOMO-1KRASG13D and SKM-1KRASK117N cells. However we did not observe any alteration in cell viability. In addition, putative STK33 downstream signaling, (phosphorylation of p70 S6K thr389 and RPS6 ser235/236) was unaltered by modulation of STK33 expression. In contrast, knockdown of KRAS caused a significant reduction in both viability and signaling in these cell lines, confirming their dependence on KRAS. A panel of 27 cancer cell lines was screened with an siRNA library representing 1500 druggable genes. STK33 siRNA had no significant effect on viability regardless of KRAS mutational status. As expected, knockdown of KRAS significantly reduced cell viability, especially in mutant KRAS cells. A kinase dead mutant STK33 was used to test the dependence on STK33 kinase activity in mutant KRAS cell lines. Transient over-expression of kinase dead STK33 in PANC-1KRASG12D and DLD-1KRASG13D cells had no effect on viability, nor on the phosphorylation of p70 S6K thr389 and RPS6 ser235/236. In summary we have been unable to confirm a synthetic lethal relationship between STK33 and KRAS. Our data do not support inhibition of STK33 as a promising therapeutic approach for targeting mutant KRAS 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 252. doi:10.1158/1538-7445.AM2011-252