bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract LB-33: Selective inhibition of Histone Deacetylase 6 enhances transformed cell sensitivity to anti-cancer agents
Authors: Namdar Mandana , Venta-Perez Gisela , Ngo Lang , Marks Paul A
Published: February 2011

Histone deacetylase (HDAC) inhibitors have emerged as promising targeted anti-cancer agents when used both in monotherapies and in combination with other anti-cancer agents. Histone deacetylase 6 (HDAC6) is a structurally and functionally unique member of the histone deacetylase family. HDAC6 has two catalytic sites, a ubiquitin binding site, cytoplasmic localization and deacetylates a number of non-histone proteins such as tubulin, HSP90 and peroxiredoxins. This study aims to unravel HDAC6-mediated anti-cancer effects and explore the therapeutic potential of HDAC6-specific inhibition in combination with other anti-cancer therapies.

We found that chemical inhibition with the HDAC6 specific inhibitor tubacin, reduces cell proliferation but does not effect cell viability in transformed cells. Tubacin significantly enhances cell death induced by anti-cancer agents such as the topoisomerase II inhibitors, etoposide and doxorubicin, as well as the pan-HDAC inhibitor SAHA in transformed cells (LNCaP, MCF-7), an effect not observed in normal cells (HFS). The inactive analog of tubacin, nil-tubacin, does not sensitize transformed cells to these anti-cancer agents. Furthermore, downregulation of HDAC6 expression by shRNA in LNCaP cells enhances cell death induced by SAHA, etoposide and doxorubicin. To explore the mechanisms of tubacin sensitization of transformed cells to anti-cancer agents, we have demonstrated that the combination treatments increases PARP cleavage and that the pan-caspase inhibitor Z-VAD-fmk, partially inhibits cell death induced by combination therapy.

Thus, HDAC6 inhibition can significantly increase transformed cell sensitivity to anti-cancer agents and highlights the importance of HDAC6 as a target for cancer therapy.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr LB-33.
Abstract LB-335: Retinoic acid regulates TRAIL-R1 expression through a retinoic acid receptor-dependent mechanism and enhances death receptor-induced apoptosis
Authors: Dhandapani Latha , Yue Ping , Ramalingam Suresh S. , Khuri Fadlo R. , Sun Shi Yong
Published: February 2011

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) receptor 1 (TRAIL-R1) also known as death receptor 4 (DR4), is a death domain containing transmembrane receptor involved in TRAIL-mediated apoptosis. One biological function of retinoic acid (RA) among many others is to regulate apoptosis, in part through TRAIL induction. The current study reveals another novel mechanism by which RA modulates apoptosis. For the first time, we found that RA increased TRAIL-R1 expression in various types of human cancer cell lines; this effect could be abrogated by the transcriptional inhibitor actinomycin-D. Moreover, RA increased TRAIL-R1 mRNA level and transactivated its promoter. These data collectively indicate that RA induces TRAIL-R1 expression at the transcriptional level. We also found that RA-induced TRAIL-R1 expression could be abolished by some retinoic acid receptor (RAR) antagonists, whereas various RAR agonists upregulated TRAIL-R1 expression, suggesting that RA induces a RAR-dependent TRAIL-R1 expression. Importantly, we identified two putative RA responsive elements (RARE) named RARE-Pal17 (a palindrome separated by 17 bases) and RARE-DR11 (a direct repeat separated by 11 bases) in the 5′ flanking region of TRAIL-R1 gene. Deletion and mutation of RARE-DR11, but not RARE-Pal17, abrogated RA's effect on transactivation of TRAIL-R1 promoter. In agreement, ChIP assay detected only RARE-DR11 binding, but not RARE-Pal17 binding, in RA-treated cells. These data collectively indicate that the RARE-DR11 is an active one that is responsible for TRAIL-R1 gene transactivation by RA. Furthermore, RA, when combined with TRAIL or agonistic anti-TRAIL-R1 antibody, augmented apoptosis in cancer cells. Taken together, the current study provides compelling evidence that TRAIL-R1 is a RAR target gene and mediates modulation of death receptor-induced apoptosis by RA, thus highlighting a novel mechanism by which RA modulates apoptosis.(SSR, FRK and SYS are Georgia Cancer Coalition Distinguished Cancer Scholars. This study was supported by funds from the Georgia Cancer Coalition Distinguished Cancer Scholar, NIH Head and Neck SPORE P50 CA128613 and DOD VITAL awards)

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr LB-335.
Abstract LB-339: Claudin-7 increases chemosensitivity to cisplatin in human NCI-H522 lung cancer cells
Authors: Hoggard John E. , Lu Zhe , Lu Qun , Chen Yan-Hua
Published: February 2011

Lung cancer is a leading cause of cancer death for both men and women worldwide. The 5-year survival rate for lung cancer is only 15%, and it accounts for approximately 1.4 million deaths every year. Recently, it has been reported that changes in expression level of claudin proteins, a family of tight junction integral membrane proteins, has been associated with several types of cancer tissues. Claudin proteins are vital components of the tight junction complex, playing a crucial role in maintaining cell polarity, adhesion, and paracellular permeability. Studies have illustrated that claudin-7 expression is lost in head, neck, invasive breast cancer, and certain types of lung cancer. The aim of this study is to investigate the role of claudin-7 in human lung adenocarcinoma cancer cells. We transfected claudin-7 cDNA tagged with myc into NCI-H522 cells, which have no detectable expression of claudin-7. H522 cells transfected with vector alone were used as a control. Claudin-7 expression in transfected cells was confirmed by western blot analysis and immunofluorescence microscopy probing for claudin-7 and myc tag. Flow cytometry analysis demonstrated that cells transfected with claudin-7 had a significantly higher percentage of cell apoptosis when compared to that of the vector transfected cells. Cell viability analyzed by MTT assays was significantly decreased, and cell apoptosis by Annexin V assays was significantly increased in claudin-7 transfected cells compared to that of vector transfected cells after cisplatin treatment. Cisplatin is an anti-cancer drug clinically used to treat tumors in several tissues including lung tumors. Furthermore, we found that claudin-7 transfected cells exhibited upregulation of caspase-3, -8, and -9. We propose that claudin-7 expression in H522 lung cancer cells increases chemosensitivity to cisplatin through increased activation of the caspase pathway. This work is supported by NIEHS.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr LB-339.
Abstract LB-340: Inhibition of autophagy enhances the anticancer activity of the retinoic acid derivative VN/12-1 in endocrine resistant human breast cancer cell lines
Authors: Godbole Abhijit M. , Purushottamachar Puranik , Gediya Lalji K. , Njar Vincent C. O.
Published: February 2011

Breast cancer is the most common cancer and the second leading cause of cancer related deaths among women in the United States. Although endocrine therapies such as anti-estrogens and aromatase inhibitors have improved the overall survival, resistance to this therapy remains a major concern. Autophagy is a unique, regulated mechanism of cell survival by catabolism of proteins under nutrient deprivation or chemotherapeutic stress. It is an important cause of resistance to chemotherapeutic agents. VN/12-1, a novel 4-imidazolyl methyl ester of retinoic acid synthesized in our laboratory, showed excellent anti-proliferative activity (as shown by MTT assay) in endocrine resistant human breast cancer cell lines SK-BR-3 and MDA-MB-231. Its IC50 in SK-BR-3 cells was 5.2 μM compared to 15.2 μM (all-trans retinoic acid-ATRA) and 45.6 μM (letrozole). For MDA-MB-231 cells, IC50 of VN/12-1 was 7.3 μM compared to 53.7 μM (ATRA) and 74.3 μM (letrozole). At low micromolar concentrations of VN/12-1 treatment on these cells, western blot analysis and imaging studies confirmed the presence of autophagosomes. This was associated with up-regulation of proteins involved in endoplasmic reticulum (ER) stress, markers for DNA damage and downregulation of cyclin D1 and phosphorylated Akt. Co-treatment with chloroquine (an autophagy inhibitor) resulted in increased sensitivity of cells to VN/12-1 as indicated by decrease in cell viability from 71.22% for VN/12-1 (3 μM) alone, 90.18% chloroquine (3 μM) alone to 34.31% for the combination of VN/12-1 (3 μM) and chloroquine (3 μM) in SK-BR-3 cells. It also resulted in induction of apoptosis which was caspase mediated.

In summary, ER stress and DNA damage induced by VN/12-1 resulted in cell cycle arrest and induction of autophagy. Inhibition of autophagy by chloroquine overwhelmed this cellular stress and resulted in apoptotic cell death in endocrine resistant breast cancer cell lines.

Significance: VN/12-1 and its combination with autophagy inhibitor chloroquine is a novel therapeutic alternative to treat endocrine resistant breast cancer and hence warrants further pre-clinical and clinical development. This is the first in vitro study which showed an enhancement of anti-cancer activity of a retinoic acid derivative by an autophagy inhibitor in endocrine resistant human breast cancer cell lines.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr LB-340.
Abstract LB-341: CD95/FAS promotes tumorigenesis
Authors: Chen Lina , Park Sun-Mi , Tumanov Alexei V. , Hau Annika , Sawada Kenjiro , Feig Christine , Turner Jerrold R. , Fu Yang-Xin , Romero Iris , Lengyel Ernst , Peter Marcus E.
Published: February 2011

FAS/CD95 has been known as a typical death receptor that enhances cell apoptosis mainly in the immune system. Recent studies indicate that CD95 expression is rarely absent or down-regulated in solid tumors and CD95L, the cognate ligand that binds cell membrane CD95, is constantly shown to be elevated in patient serum as well as tumor microenviroment, raising the question whether CD95 acturally enhances tumorigenesis and through what mechanisms. By stably knocking down endogeneous CD95 expression level using lentivirus based shRNA in six different tumor cell lines that represent liver (HepG2), colon (HCT116), renal (CAKI-1), breast (MCF7), ovary (SKOV3ip1 and HeyA8), in all cases the CD95 knockdown tumor cell lines show a clear reduction in proliferation rate comparing with the corresponding vector control cells. Injection CD95 knockdown SKOV3ip1 cells i.p. into nude mice according to method of well established xenograft ovary cancer animal model again shows a reduced tumor load and this is also confirmed by using a early passage human ovary cancer cell line MONTY-1. Human neutralizing anti-CD95L mAb (NOK-1) rather than mouse anti-CD95 mAb (MFL3) injection into these xenografted nude mice significantly reduced the tumor load, indicating that it's the CD95L secreted by tumor cells rather than the mice microenviroment that stimulates the tumor proliferation. Knocking down FasL expression from the six tumor cell lines mentioned above reduced cell proliferation even more dramatically than knocking down Fas and some cell lines, like HepG2, CAKI-1, MCF7 and HeyA8, even stop growing with reduced FasL expression. The reduced tumor formation by losing FAS/CD95 was also confirmed in vivo in two animal models: DEN induced liver cancer model by using FAS/CD95 liver specific knockout mice and Ade-Cre induced ovary cancer mouse model by generating Fas knockout mice from a mice stain with background of mutated k-ras and deleted Pten expression (LSK-K-ras(G12D/+)Pten(loxP/loxP)). The tumorigenic activity of CD95 is further identified as mediated through the CD95L-CD95-JNK-c-Jun-Fos and EGR1 pathway. These results demonstrate that CD95 plays a major growth promoting role during tumorigenesis and suggest that efforts to inhibit its activity rather than to enhance its activation should be considered during cancer therapy.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr LB-341.
Abstract LB-358: Carcinogen-induced epigenetic silencing of miR-205 and miR-200 family promotes EMT and transformation of lung epithelial cells
Authors: Tellez Carmen S. , Juri Daniel , Do Kieu , Bernauer Amanda , Thomas Cindy , Leng Shuguang , Tessema Mathewos , Damiani Leah A. , Belinsky Steven A.
Published: February 2011

An in vitro carcinogen-induced transformation model was developed using immortalized bronchial epithelial cells (HBECs) to identify key molecular changes in preneoplastic lung epithelial cells that occur during the development of lung cancer in smokers. HBECs were treated for twelve weeks (one exposure per week) with low-doses of tobacco carcinogens (MNU and BPDE) that resulted in transformation from genotoxic stress (DNA damage). The HBECs displayed a morphological change consistent with an epithelial-to-mesenchymal transition (EMT) after 4 weeks of carcinogen treatment that persisted in colonies that were recovered and expanded from soft agar (transformed cell line). Expression of mesenchymal markers vimentin, fibronectin, and N-cadherin increased significantly, while the epithelial marker E-cadherin was significantly decreased. The most notable changes associated with EMT included 4 - 55 fold reduced expression of miR-200b, -200c, and -205 that correlated with 2-1500 fold increased expression of E-box binding transcription factors (SNAI1, ZEB1, ZEB2) and basic helix-loop-helix transcription factor (TWIST1). Restoring the expression of miR-200b, -200c or -205 in carcinogen transformed cells prevented growth in soft agar; meanwhile the cells maintained a fibroblast-like mesenchymal appearance. Levels of DNA methyltransferase 1 (DNMT1) protein also increased significantly during carcinogen treatment and stable knockdown of DNMT1, but not DNMT3A and DNMT3B prior to carcinogen prevented EMT and transformation. ChIP for H3K4me2 (indicative of active/open chromatin) revealed a progressive decrease of this mark at the promoters of miR-200b, -200c, and -205 over 12 weeks of carcinogen treatment and during transformation. A modest enrichment for H3K9me2 (inactive/closed chromatin mark) was observed at all time points. In contrast, H3K27me3 (indicative of inactive/closed chromatin) was enriched at the miR promoters after 4 weeks of carcinogen treatment and enrichment declined over time. Bisulfite sequencing revealed CpG DNA methylation increased from 3% to 42% in the miR-200 family and miR-205 promoters during transformation. To examine the clinical relevance of miR-200b, -200c, and -205 their expression was analyzed in lung tumors relative to distant normal lung tissue from 24 patients. Reduced expression of at least one miR was observed in 50% of lung adenocarcinomas. These findings implicate a major role for epigenetic regulation of EMT that extends beyond that of cancer metastasis to causality for development of premalignant lung cancer. Supported by ES008801.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr LB-358.
Abstract LB-365: Regulation of VEGFR-2 by leptin-Notch signaling crosstalk in mammary cancer cells
Authors: Guo Shanchun , Fuller Miles , Gonzalez-Perez Ruben R.
Published: February 2011

VEGFR-2 (Flk-1 or KDR) is generally recognized as the major form that mediates VEGF-induced response and the earliest marker for endothelial cell development. More importantly, VEGFR-2 directly regulates tumor angiogenesis and cancer cell survival through autocrine/paracrine mechanisms. We have previously reported that leptin signaling induced the growth of breast cancer mainly through the up-regulation of pro-angiogenic and pro-proliferative molecules, i.e., VEGF/VEGFR-2. Disruption of leptin signaling markedly reduced the growth of tumors and the expression of VEGFR-2 in mouse models of syngeneic and human breast cancer xenografts (ER+ and ER-). On the other hand, Notch signaling is essential for tumor angiogenesis. We hypothesized that a crosstalk between Notch and leptin signaling could impact the expression of VEGFR-2 in breast cancer. To test this hypothesis, the 5′-end transcription region of mouse VEGFR-2 gene was cloned and used to establish VEGFR2-Luc assays in mouse mammary tumor (MT) cells. Leptin induced VEGFR-2-Luc activity through JAK2, JNK, p38 MAP kinase, as well as PKC signaling pathways and up-regulated several members of Notch family (Notch 1∼4) in MT. Interestingly, leptin-induced VEGFR-2 transcriptional activity was significantly inhibited by a gamma-secretase inhibitor which blocks Notch pathway activation. These results suggest that leptin and Notch signaling crosstalk could impact on angiogenesis and growth of MT. Furthermore, VEGFR-2 transcription and expression was heavily depending on VEGFR-2 gene methylation and histone acetylation that could be linked to leptin's effects. Our results provide novel evidence on how VEGFR-2 could be regulated in breast cancer. Present data reinforce the idea that disruption of leptin signaling could reduce tumor angiogenesis/growth by inhibiting leptin-mediated up-regulation of VEGFR-2 and/or by negatively impacting on signals from some key members of Notch family. This might help to design new pharmacological strategies aimed at controlling breast cancer growth and angiogenesis. [This work was supported in part by NIH/NCI 1SC1CA138658-02; NIH/ARRA/3SC1CA138658-02S1; NIH/UAB Breast SPORE Career Development Award and the Georgia Cancer Coalition Distinguished Cancer Scholar Award (to RRGP)].

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

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr LB-365.
Abstract LB-369: Sphingosine-1-phosphate (S1P) as a novel target in renal cancer (RCC)
Authors: Bhatt Rupal S. , Zhang Liang , Bullock Andrea , Wang Xiaoen , Moreno Kelli , Signoretti Sabina , Atkins Michael B. , Sabbadini Roger , Mier James W.
Published: February 2011

Although treatment of patients (pts) with metastatic RCC with VEGFR2 inhibitors induces disease regression, these responses tend to be short-lived. Mouse models of VEGFR TKI treatment of RCC were used to study the mechanisms of resistance and identify novel targets. Drug-induced growth arrest was associated with enhanced expression of sphingosine kinase (sphk) whose only product is the bioactive signaling lipid, S1P.

To explore the role of this pathway in mice bearing 786-O RCC were treated with a neutralizing antibody against S1P. Vehicle treated tumors increased by 2mm after 5.8 ± 4.1 days (n=6) and treatment with 10mg/kg or 50mg/kg anti-S1P led to growth after 15.3 ± 3.5 days (n=7) and 20.5 ± 3.9 days (n=6) respectively (P<0.01 for PBS vs. 10mg/kg or 50mg/kg), demonstrating that anti-S1P exhibits single agent activity in treatment naïve tumors.

To assess the activity of S1P ab in the setting of sunitinib resistance, mice whose tumors developed resistance to sunitinib, were switched to either an anti-isotype negative control antibody, or anti-S1P. Treatment with anti-S1P produced relative tumor stabilization: 23.0 ± 16.5 days (n=10) vs. isotype control 6.9 ± 2.1 days for switch to isotype (n=7, P=0.01). In an A498 RCC tumor xenograft model, vehicle and isotype treated tumors increased by 2mm after 5.0 ± 1.17 days (n=7) compared to15.3 ± 5.8 days (n=6) for mice treated with 50mg/kg anti-S1P (P<0.01) and time to reach sacrifice size of 20mm was 30.7 ± 3.8 days (n=7) in vehicle and isotype treated tumors and 45.0 ± 8.6 days (n=6) with 50mg/kg anti-S1P (P=0.01).

S1P levels in pts with RCC were found to be significantly higher than control pts (2.7 ± 0.032uM (n=23) vs 0.588 ± 0.057 M (n=20, P<0.0001). Thus, the S1P pathway is a novel target for the treatment of both treatment naïve and VEFGR TKI refractory RCC and anti-S1P therapy is an attractive new option for clinical investigation in RCC patients. The humanized anti-S1P mAb, ASONEPTM, has recently completed Phase I clinical trials in cancer and planning for Phase II efficacy trials is underway.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr LB-369.
Abstract LB-375: Development of new compounds specifically targeting prostate cancer bone metastases
Authors: Levine Alice C. , Weinstein Barrie , Liu XinHua , Regan Steven , Janout Vasek , Kirschenbaum Alexander
Published: February 2011

Introduction: Bone metastases are a major cause of morbidity for men with prostate cancer (PCa). Although PCa cells produce osteoblastic metastases, there is an initial and ongoing osteoclast (OC)-mediated osteolytic phase that is essential for PCa bone metastases. OC-mediated bone resorption is dependent upon OC secretion of bone acid phosphatase. PCa cells in bone secrete high levels of prostatic acid phosphatase (PAP) which differs from BAP in that PAP enzymatic activity is inhibited by tartrate and glyceric acid, whereas BAP is tartrate-resistant.

Hypothesis: PAP secreted by human PCa cells in bone acts similarly to OC-derived bone acid phosphatase to degrade bone matrix and enhance PCa bone-targeting and growth in bone. We developed new compounds consisting of glyceric acid or tartrate (known PAP inhibitors) conjugated to a bisphosphonate to inhibit PCa bone metastases.

Methods: PCa bone metastases derived from 7 patients were immunostained for androgen receptor (AR), prostate specific antigen (PSA) and PAP expression. The VCaP human PCa cell line derived from a vertebral metastases was inoculated intratibially into SCID mice (n=8) and bone lesions immunostained for AR, PSA, and PAP. Co-cultures of MC3T3 osteoblasts and VCaP cells were treated with tartrate and the effects on cell number, PAP and bone alkaline phosphatase (ALP) secretion measured by ELISA. Glyceric Acid and Tartaric acid were then conjugated with alendronate and the effects of these new conjugates on PAP enzymatic activity were compared to alendronate alone and tartrate alone.

Results: Human PCa bone lesions (7/7) had strongly positive expression of PAP, with little AR or PSA expression. 8/8 SCID mice inoculated with VCaP cells intratibially developed osteoblastic VCaP lesions and these similarly had high PAP expression and no PSA expression. Tartrate addition to co-cultures of VCaP and MC3T3 osteoblasts reduced MC3T3 cell numbers and ALP secretion. In vitro testing of the conjugates revealed that the glyceric acid-alendronate conjugate inhibited PAP enzymatic activity but the tartrate-alendronate conjugate and alendronate alone had no significant inhibitory activity.

Discussion: We have evidence that PAP secretion by PCa cells enhances their bone metastatic ability. We have developed new bone-targeting agents that consist of alendronate conjugated to PAP-inhibitory small molecules for further development as oral agents to prevent and treat PCa bone metastases.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr LB-375.
Abstract LB-403: Levels of nitric oxide and prostate cancer development in healthy US men enrolled in the Health Professionals Follow-up Study
Authors: Wu Tianying , Wang Yushan , Ho Shuk-Mei , Giovannucci Edward
Published: February 2011

Nitric oxide (NO) has a strong impact on cancer development. Experimental studies have reported that, depending on levels, NO has either tumoricidal or tumor-promoting effects. In addition, NO is strongly associated with oxidative and inflammatory pathways, which have been implicated in prostate cancer. In general, maintaining normal-range levels of NO is important for physiological function and may actually have tumoricidal effects. Furthermore, extremely high levels of NO have been found to stimulate prostate tumor growth in rats. However, the relationship between plasma NO level and risk of prostate cancer (PCa) development has not been assessed.

NO is difficult to measure directly in large epidemiologic studies. This barrier has hampered the identification of NO-related pathways in cancer development. We have found that plasma levels of nitrite/nitrate, measured as a surrogate marker of NO, are both stable and reproducible within individuals over time. Using a prospective nested case-control design, we identified 600 PCa cases and 600 matched controls from 2000-2004 among men who provided a blood sample in 1993-1995. This study is nested within a blood cohort in the Health Professionals Follow-up Study. We have already measured baseline plasma levels of nitrite/nitrate in 170 cases and 170 controls. The multivariate-adjusted odds ratio of nitrite/nitrate from quintile 2-quintile 4 as compared to quintile 1 are 0.71 (95%CI, 0.24-2.75), 0.20 (95%CI, 0.05-0.75), 0.81 (95%CI, 0.30-2.91), and 1.12 (95%CI, 0.65-2.78), respectively. Our preliminary data suggest that medium levels of nitrite/nitrate maximally reduce the risk of prostate cancer, and that men with high or low levels of nitrite/nitrate may be at elevated risk of prostate cancer. Confirming our results in our remaining samples and other populations may have important implications for prevention of prostate cancer.

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

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr LB-403.
Abstract LB-406: A genetic variant near the PMAIP1/Noxa gene is associated with increased bleomycin sensitivity and cancer risk
Authors: Gu Jian , Ye Yuanqing , Spitz Margaret , Lin Jie , Kiemeney Lambertus A. , Xing Jingliang , Hildebrandt Michelle AT , Hong Waun Ki , Amos Christopher I. , Wu Xfeng
Published: February 2011

Background: Mutagen sensitivity, a measurement of chromatid breaks induced by various mutagens in short-term cultures of peripheral blood lymphocytes, is an established risk factor for a number of cancers and is highly heritable. The purpose of this study is to identify genetic predictors of mutagen sensitivity.

Methods: We conducted a multi-stage genome wide association study (GWAS). The primary scan analyzed 539,437 autosomal SNPs in 673 healthy individuals, followed by validations in two independent sets of 575 and 259 healthy individuals, respectively.

Results: One SNP, rs8093763, on chromosome 18q21showed consistent association with bleomycin sensitivity (combined P = 2.64×10-8). We observed consistently lower bleomycin-induced chromotid breaks for genotypes containing wild type allele compared with the homozygous variant genotype in the discovery set (0.71 vs. 0.90, P=3.77×10-5), in replication phase one (0.61 vs. 0.84, P=7.00×10-5), and in replication phase two (0.65 vs. 0.68, P=0.44). This SNP is approximately 64 kb from the PMAIP1/Noxa gene, which is a radiation- and bleomycin-inducible gene and exhibits significantly higher expression in bleomycin-sensitive lymphoblastoid cell lines than insensitive cell lines upon bleomycin treatment. This SNP also appeared to increase the risk of lung cancer and bladder cancer in two large case control studies.

Conclusions: We identified a biologically plausible genetic variation on 18q21 near PMAIP1/Noxa gene that is associated with bleomycin sensitivity. The homozygous variant genotype exhibited higher bleomycin sensitivity and increased risks of lung cancer and bladder cancer.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr LB-406.
Abstract LB-409: Opposing effect of CHEK2 mutations for lung and kidney cancer: a meta analysis
Authors: Maria Timofeeva N. , McKay James , Scelo Ghislaine , Zaridze David , Brennan Paul ,   on behalf of the IARC Central European Lung CancerStudy.
Published: February 2011

Rare variants in CHEK2, checkpoint kinase 2, cell cycle control gene have been associated with various cancer sites including breast, prostate and colon cancer. Previously, two independent studies indicated a strong protective effect of CHEK2 mutations on the risk of lung and aero-digestive cancer but not kidney cancers (Brennan et al., 2007; Cybulski et al., 2008). We have conducted an independent case-control study to replicate these observed effects. 1202 cancer free controls, 481 individuals with primary lung cancer and 252 primary kidney cancer cases, all of Russian origin, were included in the study. All individuals were genotyped for the I157T variant (rs17879961) using Taqman. We also genotyped samples from the study published by Brennan et al. (2007) for three additional rare mutations found to be present in the central and eastern European population (1100delC, IVS2+1G>A and the deletion of 5Kb (across exons 12 and 14)). We used logistic regression techniques to calculate odds ratios (ORs) and 95% confidence interval (95%CIs), adjusted for age, gender and pack-years of tobacco smoking. We additionally performed a meta-analysis of central and eastern European studies investigating lung and kidney cancer and CHEK2 mutations.

Based on new data, the I157T rare variant showed a similar trend as in previous studies (OR = 0.78, 95%CI 0.43-1.40 for lung cancer and OR= 1.30, 95%CI 0.75-2.26 for kidney cancer). The combined OR for all three studies based on a fixed effects model indicated a strong protective effect of the CHEK2 I157T rare variant on the risk of lung cancer with OR of 0.43 (95%CI 0.35-0.53). The effect was stronger for squamous cell carcinoma (OR=0.21, 95%CI 0.12-0.37) and non significant for adenocarcinoma (OR=0.90, 95%CI 0.61-1.34). Results of meta-analysis on kidney cancer confirmed the previously observed increased risk effect of the CHEK2 I157T mutation with an OR of 1.38 (95%CI 1.04-1.82). Similar effects were observed for the combination of all mutations. Furthermore, haplotype analysis indicates that each mutation is characterized by unique extended haplotype consistent with the notion of a founder effect. The present study and performed meta-analysis confirmed previous opposing results for the effects of CHEK2 mutations on the risk of lung and kidney cancer. The mechanism for these inverse effects is unknown.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr LB-409.
Abstract LB-416: Genetic variants in the 53BP1 gene and risk of skin cancer
Authors: He Chunyan
Published: February 2011

TP53-binding protein 1 (53BP1) is a central mediator of the DNA damage checkpoint and plays an important role in DNA double-strand break repair. Genetic variation of the 53BP1 gene may interfere the proper repair that would result in genomic instability, leading to cell death or tumorigenesis. We conducted a skin cancer case-control study of Caucasians nested within the Nurses’ Health Study to evaluate whether common genetic variants of the 53BP1 gene are associated with skin cancer risk. We selected and genotyped 8 single nucleotide polymorphisms (SNPs) including potentially functional SNPs and tagging SNPs in the 53BP1 gene region in 218 incident melanoma, 285 incident squamous cell carcinoma (SCC) cases, 300 incident basal cell carcinoma (BCC) cases, and 870 age-matched controls. We found that three tagging SNPs (rs999047, rs2242069, and rs689647) were associated with a significantly decreased risk of BCC (additive multivariate ORs (95% CIs): 0.65(0.46-0.91), 0.67(0.49-0.90), and 0.68(0.48-0.96), respectively). The heterozygous variant of a putatively functional SNP, rs2602141, was significantly associated with an increased risk of melanoma (OR, 1.39; 95% CI, 1.01-1.90). The other two SNPs (rs1869258 and rs560191) highly correlated with rs260214 showed similar associations with melanoma risk. These SNPs (rs2602141, rs1869258 and rs560191) were also associated with lighter hair color and more moles among controls (p for trend, 0.003-0.07). The results suggest that the common genetic variants of 53BP1 are associated with pigmentary phenotypes and different types of skin cancer.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr LB-416.
Abstract LB-417: Polymorphisms and haplotypes in XRCC1 and risk of advanced non-small cell lung cancer
Authors: Kim In-Suk , Lee Gyeong-Won
Published: February 2011

Background: Base excision repair (BER) is the primary DNA damage repair mechanism for repairing small base lesions resulting from oxidation and alkylation damage. Genetic variants in XRCC1, one of the BER genes, may be associated with smoking-related cancers. We tested the hypothesis that single nucleotide polymorphisms (SNPs) and/or hyplotypes in XRCC1 are related with the risk of non-small-cell lung cancer (NSCLC).

Methods: We genotyped 3 known coding SNPs (Arg280His (rs25489), Arg399Gln (rs25487), and Gln632Gln (rs3547)) and 6 haplotype-tagging SNPs (htSNP) by Sequenom's (San Diego, CA, USA) high-throughput matrix-assisted laser desorption/ionization time-of-flight mass spectrometry in 140 NSCLC patients and 217 controls from Korea. Analyses of individual SNPs and hyplotypes were performed using unconditional logistic regression adjusted for age, sex, and smoking status. Haplotypes were reconstructed according to the genotyping data and linkage disequilibrium status of these 9 SNPs using the Haploview version 4.1 software (Broad Institute of MIT and Harvard, Cambridge, MA, USA).

Results: Minor allele heterozygotes of htSNP rs1799778 was increased risk of advanced NSCLC (adjusted OR, 2.118, 95% CI, 1.175-3.818, P= 0.013) and minor allele homozygote of htSNP rs2293036 was decreased risk of advanced NSCLC (adjusted OR, 0.363, 95% CI, 0.254-0.854, P = 0.020). Seven possible haplotypes were demonstrated in this study (Haplotype frequency >1%). The frequency of GGGGGGGGG haplotype composed of major alleles among selected all SNPs, was 0.109 and this haplotype showed protective effect of NSCLC risk (OR, 0.433; 95% CI, 0.246-0.740; P = 0.002). The association between the GGGGGGGGG haplotype and decreased risk of NSCLC was stable on permutation testing (P = 0.021). According to the smoking status, statistically significant associations between the rs1001581 polymorphisms and increased risk of NSCLC and the GGGGGGGGG haplotype and decreased risk of NSCLC risk were observed among never smokers (Adjusted P for trend = 0.005, P = 0.016), however, no association was noted among ever smokers.

Conclusions: These findings suggest that the GGGGGGGGG haplotype composed of major alleles in all selected SNPs showed protective role against development of NSCLC and the rs1001581 polymorphisms showed increased risk of NSCLC in Koreans, especially nonsmokers, and smoking status modifies the associations between the XRCC1 genetic variants and NSCLC risk. Thus, this study presents several novel aspects on genetic susceptibility to NSCLC and larger studies of the role of the rs1001581 and haplotypes for NSCLC risk would be needed.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr LB-417.
Abstract LB-433: A new method of colorectal cancer screening using microRNA expression profiles of colonocytes isolated from feces
Authors: Koga Yoshikatsu , Yasunaga Masahiro , Takahashi Amane , Kuroda Junichiro , Baba Hideo , Matsumura Yasuhiro
Published: February 2011

Background and Aims: Early detection of colorectal cancer (CRC) is desirable because this cancer can be cured surgically if it is diagnosed at an early stage. To reduce the mortality rate of CRC, the development of a screening test by which the cancer can be diagnosed early is needed. To date, we have reported several CRC screening methods using colonocytes isolated from feces. Recently, expression analysis of oncogenic microRNA (miRNA) in serum was reported for CRC detection. Here, we conducted miRNA expression analysis in exfoliated colonocytes isolated from feces for CRC screening.

Methods: First, oncogenic miRNA expression profiles were analyzed in CRC tissue and normal tissue. Next, 206 patients with CRC and 134 healthy volunteers were enrolled in the study, and oncogenic miRNA expression in colonocytes isolated from feces was analyzed by quantitative real-time PCR.

Results: In the CRC tissue, oncogenic miRNA expression was significantly higher than in normal tissue. There was sufficient miRNA to analyze the exfoliated colonocytes of 197 CRC patients and 119 healthy volunteers. The overall sensitivity of miRNA expression analysis was 74.1% (146/197, 95% CI; 67.4-80.1) and the specificity was 79.0% (94/119, 95% CI; 70.6-85.9). The sensitivity was significantly higher for cancers in the left side of the colon (P= 0.0001).

Conclusions: miRNA was well conserved in exfoliated colonocytes. miRNA expression analysis of colonocytes isolated from feces may be useful for CRC screening. Further investigation of oncogenic miRNA highly expressed in CRC is needed for future CRC screening test.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr LB-433.
Abstract LB-53: Paclitaxel inhibits microtubule detachment from centrosomes
Authors: Ganguly Anutosh , Yang Hailing , Cabral Fernando
Published: February 2011

Paclitaxel has been reported to inhibit cell division by suppressing microtubule dynamics at low concentrations that do not alter microtubule polymer levels. Although our studies confirm that paclitaxel suppresses microtubule dynamics at low concentrations, we show that suppression of dynamics is insufficient to inhibit cell proliferation. Wild-type CHO cells exhibited a dose-dependent decrease in microtubule dynamicity that reached a minimum at concentrations that had no observable effect on the ability of the cells to divide. Moreover, paclitaxel-dependent mutant cells that assemble reduced amounts of microtubule polymer and require paclitaxel for proliferation, exhibited a similar dose response for suppression of dynamics but much higher drug concentrations were needed to restore cell division. Thus, maximal suppression of microtubule dynamics neither inhibited the proliferation of wild-type cells, nor rescued cell division in paclitaxel-dependent cells. Instead, the higher concentrations of drug needed to restore mutant cell division caused the disappearance of microtubule fragments commonly seen in these cell lines. Using live cell imaging, we found that microtubule fragments are generated by detachment from microtubule organizing centers, and that paclitaxel acts to prevent this detachment, thereby raising microtubule polymer levels. We conclude that low paclitaxel concentrations act at microtubule plus ends to inhibit dynamics, but that higher concentrations are needed to inhibit cell division and prevent microtubule detachment from organizing centers.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr LB-53.
Abstract LB-69: Targeting CK2 with small molecule CX-4945 modulates NF-kappaB, TP53 and cell survival in head and neck squamous cell carcinoma
Authors: Kannabiran Vishnu , Friedman Jay , Lu Hai , Anderes Kenna , Chen Zhong , Van Waes Carter
Published: February 2011

Objective: We previously identified CK2 as an upstream kinase activating NF-kappaB and modulating TP53 mediated signaling pathways. Up regulated CK2 activity is implicated in promoting the malignant phenotype and progression of head and neck squamous cell carcinoma (HNSCC). Here, we investigate the antitumor effects of CX-4945, a selective small molecule inhibitor of CK2.

Design: The effects of CX-4945 on cell proliferation were measured by MTT assay in a panel of 9 University of Michigan squamous cell carcinoma (UM-SCC) cell lines. The half maximal inhibitory concentration (IC50) was determined in vitro. CX-4945 inhibition of cell cycle and induction of cell death were measured by DNA flow cytometry. The effects of CX-4945 on the activity of NF-kappaB, BCL-XL, and TP53 promoters were tested by the chemiluminescent reporter gene assay. The anti-tumor activity of orally administered CX-4945 was evaluated in SCID mice bearing UM-SCC-11A xenografts.

Results: The IC50 in 9 UM-SCC cell lines ranged from 3.4 µM to 11.7 µM. The UM-SCC-11A cell line used for in vivo studies had an IC50 of 4.07 µM in vitro. CX-4945 showed a concentration and time dependent cell cycle arrest in G1 and G2/M phases accompanied by a significant induction of sub-G0 cells indicating cell death. CK2 inhibition with CX-4945 downregulated the reporter activities of survival-promoting genes such as NF-kappaB and BCL-XL and up regulated the reporter activity of apoptosis-promoting gene TP53 in a concentration and time dependent manner. Furthermore, CX-4945 (75 mg/kg) showed significant tumor growth inhibition (31% (p<0.05)) in UM-SCC-11A xenografts compared to the control group.

Conclusions: Inhibition of CK2 via CX-4945 reveals anti-proliferative activity and modulation of NF-kappaB activation in HNSCC cell lines. In vivo studies show significant antitumor activity in a bortezomib-resistant HNSCC xenograft model. CK2 is an unexploited target in HNSCC and CX-4945 demonstrates the potential of a therapeutic agent with this novel mechanism of action for the treatment of head and neck cancers. (Supported by NIDCD intramural project ZIA DC-000016)

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr LB-69.
Abstract LB-71: Stage Ia vs. Ib endometrial stromal sarcoma: Does the new staging system predict survival
Authors: Garg Gunjal , Shah Jay P. , Morris Robert T.
Published: February 2011

Background: In 2008, a new FIGO staging system was specifically designed and approved for endometrial stromal sarcoma. Our objective was to determine the impact of this new staging system on survival in patients with stage I endometrial stromal sarcoma (ESS).

Methods: Data were extracted from the Surveillance, Epidemiology, and End Results database between 1988 and 2005. Kaplan-Meier log rank and Cox proportional hazards models were used for survival analysis and to identify possible predictors for survival.

Results: The identified cohort included 464 women, with 310 (67%) low-grade endometrial stromal sarcoma (LGESS), 96 (21%) high-grade endometrial stromal sarcoma (HGESS), and 58 (12%) unclassified ESS. LGESS compared to HGESS differed significantly with regards to the patient age (48 vs. 60 years, p<0.001), tumor size (5.6 cm vs. 8.0 cm, p<0.001), cervical involvement (5.2% vs. 18.8%, p<0.001), myometrial invasion (62% vs. 66.6%, p=0.01), and stage IB disease (44% vs. 76%, p<0.001). Similarly, compared with LGESS, a greater percentage of HGESS patients underwent lymphadenectomy (29.0% vs. 60.4%; P <0.001), salpingo-oophorectomy (78.4% vs. 93.7%, p=0.001), and administration of radiotherapy (14.8% vs 50.0%; P<0.001). There was no significant difference between stages IA and IB with regards to the above-mentioned demographic and clinico-pathologic variables, in both LGESS and HGESS. The 5-year overall survival was worse in HGESS than LGESS (45.4% vs. 97.2%, p<0.001). The difference in 5-year overall survival between stages IA and IB was significant in LGESS (100% vs. 93.5%, p=0.003), but not in HGESS (51.4% vs. 43.5%, p=0.2). Although age (p=0.001), race (p= 0.005), stage (p=0.004) were all significant prognostic factors in LGESS, only cervical involvement (p=0.02) was a significant predictor in HGESS.

Conclusion: The new staging system is appropriate for risk stratification in LGESS. The prognosis in HGESS seems to be most influenced by the presence of cervical involvement and not by tumor size as the staging criteria would suggest.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr LB-71.