bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 2662: Pharmacokinetics, metabolism and tissue distribution of the nitric oxide-donating prodrug JS-K following administration in liposomes
Authors: Buhrow Sarah A. , Reid Joel M. , Walden Chad A. , Jia Lee , Davis Myrtle , Keefer Larry K. , Barazi Heba , Ames Matthew M.
Published: February 2011

The diazeniumdiolate O2-(2,4-dinitrophenyl)-1-[(4-ethoxycarbonyl)piperazin-1-yl]diazen-1-ium-1,2diolate (JS-K, NSC 724771) is a nitric oxide (NO)-donating prodrug that was designed to release NO upon reaction with glutathione-S-transferase which is overexpressed in some tumors. We demonstrated that JS-K reacts with nucleophiles in biological fluids and has an extremely short half-life in mice. The purpose of the study was to test the hypothesis that liposomal encapsulation improves the in vivo half-life, tissue distribution and acute toxicity profile of JS-K. We investigated the pharmacokinetics of [3H]JS-K in CD mice administered the drug in DMSO or DMPC (dimyristoylphosphatidylcholine) liposomes (20:1 molar ratio of DMPC: JS-K) and in tumor-bearing athymic nu/nu NCr mice administered the radiolabeled drug in DMPC liposomes. The terminal elimination half-life of total radioactivity (2 hours) was similar for both formulations. We did not detect [3H]JS-K in any plasma or red blood cell samples from mice administered 6 mg/kg JS-K in DMSO and only trace amounts of [3H]JS-K were detected in samples collected at the earliest time-points from mice administered 6 mg/kg JS-K in DMPC liposomes. Small amounts of radioactivity, presumably associated with JS-K metabolites, were detected at the solvent front of HPLC chromatograms. Very little radioactivity and no JS-K was detected in tumor samples. Finally, we developed an LC/MS/MS assay to investigate formation of JS-K metabolites in biological samples and used that method to measure concentrations of JS-K and its metabolites in plasma, red blood cells, liver tissue and tumor tissue collected from tumor-bearing mice administered 3 mg/kg or 6 mg/kg JS-K in DMPC liposomes. We confirmed extremely rapid in vivo degradation of JS-K in the systemic circulation following intravenous administration and rapid formation of several expected metabolites including high concentrations of the glutathione conjugate of the dinitrophenol moiety and piperazine. Supported by NCI Contract NO1-CM-52206.

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 2662.
Abstract 2670: CONFORMATIONAL PLASTICITY OF HUMAN THYMIDYLATE SYNTHASE
Authors: LUO BEIBEI , Berger Sondra H.
Published: February 2011

Thymidylate synthase (TS), catalyzes the reaction that forms dTMP from dUMP. Previous data suggested that human thymidylate synthase (hTS) exists in two major conformations, active and inactive. Two hTS mutants were created to mimic the active and inactive forms. The mutant, designated R163K, has an arginine to lysine substitution at residue 163 and crystallizes in an active conformation in the native state. The other one, A191K, has an alanine to lysine substitution at residue 191 and is stabilized in the inactive form. To further test whether the mutants exhibit different conformations in solution, circular dichroism was used to compare solution structures and detect the effects of ligand binding. Relative to hTS, the CD spectra of both R163K and A191K showed a decreased ellipticity. Upon ligation with dUMP, A191K exhibited a further decrease in ellipticity and showed no apparent response to phosphate. In contrast, the ellipticity of R163K was increased by phosphate and dUMP produced a further increase in ellipticity. Crystal structures suggested that the catalytic thiol of R163K is more susceptible to modification by oxidation compared to hTS. Thus, we postulated that the inactive form functions to sequester the catalytic thiol from oxidation. To test the hypothesis, we conducted studies of the rate of modification of purified enzymes with the thiol-reactive agent, 5, 5′-dithiobis(2-nitrobenzoic acid) (DTNB). Relative to hTS, a slight increase in oxidation rate was observed in the active-stabilized mutant; however, the rate of catalytic inactivation of hTS was faster. In vivo, TS-deficient transfectants expressing R163K were more sensitive to oxidative stress relative to cells expressing wt hTS. The data provide preliminary evidence of a protective role of the inactive form under the oxidative stress although the basis for this effect remains unclear.

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 2670.
Abstract 2687: Development of a new, highly sensitive assay for circulating tumor cell (CTC) detection based on the CellSearch® CTC Profile Kit enrichment and laser scanning cytometry analysis
Authors: Melnikova Vladislava O. , Liu Wen , Zhang Yujian , Hong David S. , Davis Darren W.
Published: February 2011

The presence of CTCs in the peripheral blood, as detected by the FDA-approved CellSearch® CTC Kit, is associated with decreased overall and progression free survival in patients with metastatic breast, prostate and colorectal cancers. In addition to CTC enumeration, CellSearch® CTC Kit provides a unique tool for CTC biomarker analysis in cancers of epithelial origin (CD45—, EpCAM+, and cytokeratins (CK) 8,18-positive and/or 19-positive). Considerable cell loss is suspected to occur at many of the automated steps of the CellSearch® CTC process, resulting in undermined recovery of CTCs. Herein, we demonstrate an improved, highly sensitive approach for CTC enumeration, which is based on the CellSearch® CTC Profile Kit and immunofluorescent analysis using LSC. The initial blood processing was conducted using the CellSearch® CTC Profile Kit from Veridex and the CellTracks® AutoPrep® system, which allowed recovery of the EpCAM+ cells directly from the instrument. Next, EpCAM+ cell population was subjected to manual immunofluorescent labeling with antibodies against CK and CD45, and CTCs were enumerated by LSC, based on the standard CellSearch® CTC criteria. When we compared this new method to standard CTC enumeration in patients with various cancer types including head and neck, renal cell, basal cell, prostate, non-small cell lung, sebaceous gland and ovarian cancers, we consistently detected higher CTC counts in samples analyzed with the new method. Indeed, 88% of patients (79 out of 90) were CTC-negative based on the standard analysis, while only 37% of patients were CTC-negative based on the CTC Profile Kit/LSC data. We next conducted a side-by-side comparison of the two techniques in patients with hepatocellular carcinoma (HCC, EpCAM-low) and prostate cancer (EpCAM+). CTC Profile Kit/LSC method demonstrated up to a 470% increased CTC recovery in the prostate cancer samples. Remarkably, it also allowed isolation of CTCs from the CTC-negative (as detected by the standard kit) HCC and prostate cancer samples. Finally, the new CTC enumeration method consistently yielded higher CTC counts in patients enrolled in a Phase I clinical trial of Bevacizumab and Cediranib. Importantly, our preliminary analysis indicated that changes in CTC counts from baseline to 24 h post-therapy, as measured by the new method, may correlate with changes in tumor size. In conclusion, we developed a new CellSearch® CTC Profile Kit/LSC-based method that offers higher sensitivity of CTC recovery and thus provides a broader capability for downstream molecular characterization.

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 2687.
Abstract 2703: Loss of dependence on EGFR signaling by upregulation of Mig6 confers drug resistance to erlotinib
Authors: Chang Xiaofei , Chatterjee Aditi , Huang Shyhmin , Kim Myoung Sook , Shao Chunbo , Monitto Constance L. , Ha Patrick K. , Hidalgo Manuel , Harari Paul M. , Berman David M. , Bedi Atul , Sidransky David
Published: February 2011

We sought to elucidate mechanisms of resistance to epidermal growth factor receptor (EGFR)-targeted therapies and to identify markers that could better distinguish resistant from sensitive patients. Here we show that mitogen-inducible gene 6 (Mig6), a negative regulator of EGFR, was selectively upregulated during the evolution of resistance to the EGFR tyrosine kinase inhibitor (TKI) erlotinib in lung and head and neck cancer cell lines. Mig6 was a major determinant of EGFR activity in panels of cancer cell lines of different tissue origins, and in direct validation of approved human use, in a unique collection of directly xenografted human lung and pancreas tumors. Our work highlights the importance of cellular negative regulators of EGFR in predicting and subverting TKI responsiveness, and identifies the ratio of Mig6 to EGFR, rather than the absolute expression of either protein alone, to be a predictor of tumor cell response to erlotinib.

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 2703.
Abstract 2783: Mammotrophic hormone score and risk of postmenopausal breast cancer
Authors: Tworoger Shelley S. , Eliassen Heather , Rosner Bernard , Hankinson Susan E.
Published: February 2011

Sex hormones and prolactin have been positively associated with risk of breast cancer among postmenopausal women. However two small studies suggested that having multiple hormones above the age-adjusted mean level did not further increase the risk of breast cancer beyond having only one hormone above the mean. This suggests a possible threshold effect, such that these hormones may be permissive with respect to breast cancer growth and an evaluation of hormones levels at the low end of the distribution may be most informative. The goal of this study was to evaluate the combined effect of multiple hormones, including estradiol, estrone, estrone sulfate, testosterone, androstenedione, DHEA, DHEAS, and prolactin, in relation to postmenopausal breast cancer risk. We conducted a nested case-control study in the Nurses' Health Study including cases of postmenopausal breast cancer who were not using postmenopausal hormones at blood collection in 1990 and were diagnosed after blood collection but before June 1, 1998 and their matched controls. We examined the relationship between the number of hormones in which levels were above age- and batch-adjusted means (as determined in controls and referred to as the “hormone score”) and risk of breast cancer overall using conditional logistic regression adjusting for age at menopause, body mass index (BMI) at age 18, history of benign breast disease, and family history of breast cancer. We also examined estrogen receptor (ER) positive cases only using unconditional logistic regression. Overall, 265 cases (189 ER+) and 541 matched controls had measured levels for all eight hormones. The mean hormone score was 4.6 (SD=2.3) in cases and 3.9 (SD=2.4) in controls (p<0.001). There was a statistically significant 16% increase in risk for a one unit increase in the hormone score with risk of breast cancer overall (95% CI: 1.08-1.24, p-trend<0.001) and a 19% increase for ER+ tumors (95% CI: 1.10-1.28, p-trend<0.001). Women with a hormone score of 6-8 versus 0 had a significantly increased risk of breast cancer overall (RR=2.67, 95% CI: 1.26-5.62) and of ER+ disease (RR=5.30, 95% CI: 1.18-15.5). For ER+ tumors, women with a score of 3-5 versus 0 also had an increased risk (RR=3.12, 95% CI: 1.08-9.02). Despite the somewhat small number of cases, our data support that the risk of postmenopausal breast cancer increases linearly as the number of hormones with high levels rises. This suggests that proliferation and other carcinogenic processes may be sensitive to the influence of multiple mammotrophic hormones simultaneously. Further, this information could be used to develop improved risk prediction models.

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 2783.
Abstract 2790: Prospective study of urinary prostaglandin E2 metabolite and lung cancer risk
Authors: Cai Qiuyin , Gao Yu-Tang , Wen Wanqing , Milne Ginger L. , Yang Gong , Ji Bu-Tian , Rothman Nathaniel , Li Hong-Lan , Shu Xiao-Ou , Chow Wong-Ho , Zheng Wei
Published: February 2011

Cumulative evidence from both in vitro and animal studies suggests that cyclooxygenase-2 (COX-2) may be involved in the development and progression of lung cancer. Overproduction of prostaglandin E synthase and prostaglandin E2 (PGE2), one of the end products of the COX-2 pathway, has been implicated in the pathogenesis of non-small cell lung cancer. It is believed that the pro-inflammation effects of COX-2 pathway are largely mediated through PGE2. PGE2 is quickly converted to 11α-hydroxy-9,15-dioxo-2,3,4,5-tetranor-prostane-1,20-dioic acid (PGE-M), a major PGE2 metabolite and excreted from urine. In this study, we evaluated the association of urinary PGE-M levels and lung cancer risk. A nested case-control study was conducted within the Shanghai Women's Health Study, in which 74,942 Chinese women aged 40-70 years were recruited from 1997 to 2000 and followed up for up to 10 years. Urinary PGE-M in 192 incident lung cancer patients were compared to 192 matched controls. The baseline level of urinary PGE-M was comparable between cases and controls. Excluding 20 case-control pairs who were diagnosed with lung cancer within one year of follow-up or excluding 22 case-control pairs who ever smoked did not change the null association. No interaction was found between PGE-M and smoking or passive smoking in relation to lung cancer risk. Our data suggest that the PGE2 pathway may not play a major role in lung cancer development in non-smoking women. Further studies are being conducted to evaluate whether genetic variations in the PGE2 pathway will modify the urinary PGE-M and lung cancer association. Given the substantial laboratory evidence, further evaluation of the COX-2 pathway in lung cancer pathogenesis, including other urinary biomarkers and genetic variations, may be warranted.

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 2790.
Abstract 2794: Urinary estrogen metabolites and prostate cancer risk: A case control analysis using healthy and biopsy controls
Authors: Kosti Ourania , Goldman Lenka , Bebu Ionut , Hsing Ann , Collins Sean , Dritschilo Anatoly , Lynch John , Xu Xia , Veenstra Timothy , Goldman Radoslav
Published: February 2011

Prostate gland is considered as an androgen-dependent organ, however it is now recognized that estrogens and their receptors are involved in the normal and abnormal growth of the prostate gland. The aim of this study was to evaluate urinary estrogens and estrogen metabolites (EMs) as a biomarker for prostate cancer risk and identify factors that affect EM levels in urine. Using a liquid chromatography-tandem mass spectrometry method, urinary concentration of 15 EMs was determined in 77 prostate cancer cases, 77 healthy controls and 37 subjects that underwent biopsy and confirmed to be cancer-free (biopsy controls). Multivariate Analysis of Variance (MANOVA) was used to identify the interactions among the EM levels and their association to case control status. Wilcoxon rank-sum test was used to compare urinary EM concentrations individually by case status. Results showed that the 3 groups were comparable when MANOVA testing was applied. Ranking of EM concentrations showed that the catechol estrogen 4-OHE1 was relatively more abundant in prostate cancer patients compared to participants without cancer. Univariate analysis showed a tendency for the metabolites with high estrogenic activity, namely16-KE2 and 17-epiE3 to be secreted in lower amounts among prostate cancer patients. Multivariate logistic regression analysis confirmed that having low 16-KE2 (based on median of healthy controls) increased risk of prostate cancer with an adjusted odds ratio (OR) of 1.97 (95% CI, 0.86-4.52). A significant trend of increasing risk with lower 16-KE2 levels was also observed (P-for-trend = 0.02), with OR for the highest quartile of 4.62 (95% CI =1.34-15.99) compared to the lowest quartile. To identify factors that affect EM levels, we performed analysis among the healthy controls; being a current smoker was associated with a significant increase in the 2-hydroxy products 2-OHE1 and 2-MeOE1 and a marginal increase in the 2-OHE1/16α-OHE1 ratio. Age, body Mass Index (BMI), presence of diabetes, family history of prostate cancer or presence of BPH did not affect estrogen levels in our population. Our study did not allow stratified analysis by race due to the small numbers of non-Caucasian subjects. To conclude, our findings encourage further investigation of urinary estrogens and EMs as biomarkers for prostate cancer risk assessment.

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 2794.
Abstract 2796: Circulating 25-hydroxyvitamin D and prostate cancer risk in a large male cohort
Authors: Albanes Demetrius , Weinstein Stephanie J. , Snyder Kirk , Yu Kai , Horst Ronald , Virtamo Jarmo
Published: February 2011

Vitamin D compounds have been shown to inhibit prostate tumorigenesis experimentally, but based on the small number of epidemiological studies conducted to date, the relation between vitamin D status and prostate cancer risk remains unclear. We investigated the association between 25-hydroxyvitamin D [25(OH)D] and prostate cancer in a nested case-control study within the Alpha-Tocopherol, Beta-Carotene Cancer Prevention (ATBC) Study of 50-69 year old Finnish men. To 1,000 cases diagnosed during up to 20 years of follow-up, we matched 1,000 controls on age (within 1 year) and baseline blood collection date (within 30 days). Serum samples were assayed for 25(OH)D using the DiaSorin LIAISON 25(OH)D method (intra-batch and inter-batch CVs, 10.5% and 12.3%), and conditional multivariate logistic regression models estimated odds ratios (OR) and 95% confidence intervals (CI) for the prostate cancer-25(OH)D association, conditioned on the matching factors and adjusted for body mass index, residence, benign prostatic hyperplasia, and the trial supplements. 25(OH)D concentrations were categorized according to quintiles based on control cut-points of <18.6, −28.3, −39.7, >53.3 nmol/L. ORs (95% CIs) for Q1-Q5 were 1.00 (reference), 1.39 (1.04-1.86), 1.54 (1.14-2.08), 1.20 (0.88-1.62), and 1.41 (1.03-1.93)(p-trend=0.06). These findings were similar for subgroups of age, season of blood draw, time from blood draw to diagnosis, body mass index, vitamin D intake, and disease stage. Analyses of 25(OH)D based on clinically-defined categories, season-adjusted (by regression residual method), and season-specific cut-points yielded similar results. Our findings suggest that men with lower serum 25(OH)D levels may be at lower risk of developing prostate cancer compared to men with higher levels.

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 2796.
Abstract 2905: Is obesity the cause for the increasing incidence of CRC in patients under 50 years of age and can an anti-adenoma antibody identify those at risk
Authors: Hwang Allen , Elkin Daniel , Kaplan David , Antaki Fadi , Rambus Mary Ann , Leavell Bonita , Naumoff Joann , Rodriguez Rebecca , Hatfield James , Xu Yi , Patel Pragnesh , Guirguis Tatwig , Lawson Michael , Tobi Martin
Published: February 2011

CRC incidence in patients <50 years of age has increased by 17% in the last decade predominantly rectal cancer in Whites (Siegel et al, 2009). This age group is rarely screened. We determined the rectal binding Adnab-9 antibody in patients <50 years and a >50 year control at high clinical CRC risk of cancer. Methods: Adnab-9 is an adenoma-carcinoma sequence marker. We performed Adnab-9 immunohistocemistry on colonoscopic rectal biopsies. Results: Our study found that of 25 patients age <50 years, 48% had rectal binding of Adnab-9 versus 21.8% in 220 patients ≥50yrs (p<0.01) and with BMI was confirmed as an independent risk factor by multivariate analysis. Demographics are summarized (Table) and significant differences were seen for gender, ASA intake and BMI, however female gender was equally distributed 58.3 in the positive and 61.5% in the negative group. Hematochezia tended (p=0.23) to associate with positive rectal binding (50 versus 23%) and the colonoscopic finding was more likely to reveal adenomatous tissue in the positive group (58.3 versus 23.1%, p=0.11). Older patients were significantly more likely to take ASA which may have reduced the polyp number in this group and they also have an decreased BMI (p<0.02). In the entire group Adnab-9 positivity correlated with BMI as a continuous variable (U=0.03; p<0.01). Conclusions: Adnab-9 is an independent CRC risk marker in patients <50 years of age suggesting that they are more prone to development of neoplasia. The mechanism appears to be that of an adenoma-carcinoma sequence. ASA may be a factor but was not an independent mitigating marker in this study. BMI is also greater in the younger group and may be the underlying cause of the observed increase in neoplasia in the young. Adnab-9 staining of sigmoidoscopic rectal biopsies may be a convenient way of identifying a high-risk population of patients <50 years of age for CRC surveillance in this population hithertofore not afforded screening.Parameter (n)Patients <50 (25)Patients >50 (220)Age(mean+st.deviation[SD])44.8 (5.4)62.4 (9.3)% Non-Hispanic Whites4041.4% Female Gender60 (OR 11.0, CI 4.4-27.2; p<0.0001)10.9Any NSAID/Statin/ASA(%)30.4/44/41.18/4.6 (less ASA-p<0.02)37.6/46.6/30.5Symptom %/BMI(SD)60/31.6(6.1) (BMI p<0.02)*42.9/28.7(5.4)

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 2905.
Abstract 2909: ApoFLIP: A bioactive peptide that restarts the apoptotic machinery in cancer cells
Authors: Jin Taiguang , Kurakin Alexei , Song Keli , Wang Jun-Xia , Santos Tanya , Khosravi-Far Roya
Published: February 2011

The cellular factors inhibiting apoptosis are often employed by cancer cells to resist therapy. c-FLIP is an endogenous inhibitor of apoptosis upregulated in many drug resistant tumors. Herein, we show that a peptide derived from c-FLIP is a potent inducer of apoptosis in both in vitro and in vivo cancer models. Mechanistic studies suggest that the apoptogenic peptide of c-FLIP (ApoFLIP) removes the inhibition of pro-apoptotic signaling at the level of activated death receptors by competing c-FLIPL off receptor complexes and clearing the way for activation of the caspase cascade. At the same time, ApoFLIP impairs the pro-survival signaling along the PI3K/Akt pathway by blocking the interaction between the p85 subunit of PI3K and c-FLIPL. The selectivity and apoptogenic potency of ApoFLIP in killing cancer cells suggests that simultaneous targeting of two or more hallmark features of cancer may prove to be a winning therapeutic strategy.

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 2909.
Abstract 2910: Mono- or double-site phosphorylation distinctly regulates the proapoptotic function of Bax
Authors: Wang Qinhong , Wang Ton , Gao Fengqin , Sun Shi-Yong , Khuri Fadlo R. , Curran Walter J. , Deng Xingming
Published: February 2011

Bax is the major multidomain proapoptotic molecule that is required for apoptosis. It has been reported that phosphorylation of Bax at serine(S) 163 or S184 activates or inactivates its proapoptotic function, respectively. To uncover the mechanisms by which phosphorylation at these two sites regulate the proapoptotic function of Bax, a series of serine (S)→ alanine/glutamate (A/E) mutants, including S163A, S184A, S163E, S184E, S163E/S184A (EA), S163A/S184E (AE), S163A/S184A (AA) and S163E/S184E (EE), were created to mimic or abrogate, respectively, either single or double-site phosphorylation. The compound Bax mutants (i.e. EA and AE) can flesh out the functional contribution of individual phosphorylation site(s). WT and each of these Bax mutants were overexpressed in Bax−/− MEF or human lung cancer H157 cells and the proapoptotic activities were compared. Intriguingly, expression of any of Bax mutants containing the mutation S→A at S184 (i.e. S184A, EA or AA) represents more potent proapoptotic activity as compared to WT Bax in association with conformational change, mitochondrial localization/insertion and prolonged half-life. In contrast, all Bax mutants containing the mutation S→E at S184 (i.e. S184E, AE or EE) have decreased protein stability and less apoptotic activity without conformational change and mitochondrial localization/insertion. Unexpectedly, mutation either S→A or S→E at S163 site does not significantly affect the proapoptotic activity of Bax. These findings indicate that S184 but not S163 is the major phosphorylation site for functional regulation of Bax's activity. Thus, manipulation of the phosphorylation status at S184 may represent a novel strategy for treatment of cancers that express Bax.

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 2910.
Abstract 2913: Autophagy resulting from specific ablation of the proapoptotic function of cytochrome c
Authors: Li Hua , Wang Peng , Yu Jian , Zhang Lin
Published: February 2011

Apoptosis and autophagy are two evolutionarily conserved and sometimes mutually exclusive cell death regulatory mechanisms. The balance and cross talk between these two processes determine cell fate and have an important role in therapeutic response to anticancer agents. It has been shown that apoptosis can cross talk with autophagy through the actions of the Bcl-2 family proteins. For example, Bcl-2 inhibits autophagy by interacting with Beclin-1, the master regulator of autophagy. However, the underlying mechanisms by which apoptosis and autophagy regulate each other remain unclear. In this study, we investigated whether cytochrome c (cyto c), a critical regulator of the mitochondrial apoptotic pathway, is involved in regulating autophagy. A cyto c mutant (K72A) that retains its normal electron transfer function but fails to bind to Apaf-1 was knocked into HCT116 colorectal cancer cells by homologous recombination. Although the mutant cyto c can still be released from the mitochondria into the cytosol in response to apoptosis induction, caspase activation and other execution steps of apoptosis were inhibited. Remarkably, a significant increase in autophagy was observed in the cyto c-knockin cells, as indicated by formation of GFP-LC3 puncta and increased conversion of LC3-I into LC3-II. Furthermore, knockdown of Beclin-1 by siRNA suppressed autophagy in the cyto c-knockin cells. These results indicate that the execution steps of apoptosis downstream of cytochrome c release, including formation of apoptosome and activation of caspases, can inhibit autophagy. Autophagy can be unleashed when apoptosis is initiated, but fails to be executed.

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 2913.
Abstract 2936: In situ antitumor immunotherapy with pharmacological blockade of MFG-E8 and chemotherapy against solid and hematological tumors
Authors: Jinushi Masahisa , Tahara Hideaki , Koyasu Shigeo , Dranoff Glenn
Published: February 2011

The conventional anticancer strategies, such as chemotherapy and radiotherapy, induce the tumor cell death, which would theoretically become the source of tumor antigens to be recognized in situ by the immune system. However, most of the cytotoxic therapies rarely induce the immunological responses potent enough to cause obvious tumor destruction in the actual clinical settings. This discrepancy might be caused by the tumor evasion systems, which restrain the induction of host immune responses. Thus, the therapeutic efficacy of various anticancer agents could be improved if the novel strategies are found to reverse molecular machineries of tumor-mediated immune evasion.

Milk-fat globule EGF-8 (MFG-E8) has been known to maintain tissue homeostasis in multiple aspects; regulating the phagocytosis of apoptotic cells, breast tissue morphogenesis, intestinal epithelium homeostasis and angiogenesis. Here we have shown that the therapeutic interference of MFG-E8 synergistically potentiates antitumor activities of various cytotoxic and target therapies, and radiotherapy, against various murine tumors. These antitumor activities relied on the induction of the potent and specific antitumor immune responses in situ. The MFG-E8 blockade triggered infiltration and activation of dendritic cells at the tumor sites, where apoptotic cells were made available with cytotoxic treatments, resulting in the potent antitumor effector T cell activation and inhibition of Foxp3+Treg cell function. Furthermore, the administration of anti-MFG-E8 antibodies switches the receptor for MFG-E8-mediated tumor cell ingestion from integrins αvβ3 to activating FcγRI/III receptors in dendritic cell recognition of tumor cells, augmenting dendritic cell-mediated cross-priming of tumor-specific T cells.

These findings demonstrated that the blockade of MFG-E8, one of the key negative regulators to restrain immune responses against the dying cells, would be a novel strategy to improve durable antitumor responses by various anticancer therapeutic agents.

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 2936.
Abstract 2967: The p53 target gene TRIM22 colocalizes with the centrosome independently of cell cycle phase
Authors: Petersson Jessica , Lönnbro Per , Herr Anna-Maria , Mörgelin Matthias , Gullberg Urban , Drott Kristina
Published: February 2011

TRIM22 (Staf50) is an interferon (IFN)-inducible protein as well as a p53 target gene. The specific molecular function of TRIM22 is largely unknown, but TRIM22 is suggested to play a role in viral defense by restriction of viral replication. Furthermore, TRIM22 may function as an ubiquitin E3 ligase, targeting proteins for degradation. TRIM22 is highly expressed in lymphoid tissues as well as in peripheral blood leukocytes and in the ovary and lung. TRIM22 belongs to the TRIM family of proteins, named based on a characteristic tripartite-motif (TRIM), including a RING-finger, one or two B-boxes and a coiled-coil domain. The TRIM family consists of more than 70 proteins, implicated in diverse biological processes such as apoptosis, cell proliferation, viral defense and ubiquitylation. Several TRIM family members are involved in cancer. Interestingly, TRIM proteins have been suggested to identify specific cell compartments by means of multimerization. There have previously been conflicting reports regarding the subcellular localization of exogenous TRIM22. Utilizing immunoflourescence and subcellular fractionation, we show here that endogenous TRIM22 is localized to both nucleus and cytosol in the human osteosarcoma cell line U2OS. Furthermore, the same localization pattern is present in human peripheral blood mononuclear cells (PBMCs), an environment more relevant to its physiological function. Moreover, we demonstrate a colocalization of TRIM22 with the centrosomes in U2OS cells as well as in PBMCs, and show that this colocalization is independent of cell cycle phase, utilizing the centrosome markers gamma-tubulin, aurora A and pericentrin. The centrosomal localization was confirmed with electronic microscopy, suggesting TRIM22 to be localized in the pericentriolar material (PCM) and not at any specific site at the centrioles. Additionally, the colocalization with centrosomes appears to be independent on the microtubule network as shown by the microtubuli destabilizing agent nocodazole. Centrosomes are essential organelles, vital for mitosis and organization of the microtubule network as well as providing sites for viral replication, viral assembly and protein degradation. Our data suggest that centrosomal TRIM22 may have important functions in these processes. However, further studies are required to confirm this notion.

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 2967.
Abstract 2986: Melanocytes are deficient in repair of oxidative DNA damage and UVC induced photoproducts
Authors: Wang Hsiang-Tsui
Published: February 2011

Melanomas occur mainly in sunlight-exposed skin, xeroderma pigmentosum complementation (XP) patients, defective in nucleotide excision repair function, have 1000-fold higher incidence of melanoma. These findings indicate that sunlight induced “bulky” photoproducts are responsible for melanomagenesis. On the other hand, sunlight also induces a high level of reactive oxygen species (ROS) in melanoctes (MC), oxidative DNA damage (ODD) therefore may contribute to melanomagenesis and that the XP protein may participate in ODD repair. To address these questions we determined: 1) the effect of melanin on UVA (320-400 nm) irradiation induced ODD and UV photoproducts using formamidopyrimidine glycosylase (Fpg) and UvrABC incision assays, 2) the repair capacity for ODD and UV-induced photoproducts in MC and XPA cells using host cell reactivation and in vitro DNA repair synthesis assays. We found: 1) UVA irradiation-inducing a significantly higher amount of Fpg sensitive ODD in MC than in normal human skin fibroblasts (NHSF). In contrast, UVA irradiation induces an insignificant amount of UvrABC sensitive sites in either of these two types of cells. 2) Compared to NHSF, MC have a reduced repair capacity for ODD and photoproducts. 3) H2O2 modified DNA induces a higher mutation frequency in MC than in NHSF. 4) XPA cells are deficient in ODD repair and ODD induces a higher mutation frequency in XPA cells than in NHSF. Based on these results, we propose: 1) UVA is a major etiological agent for melanomagenesis and the mechanism is through melanin sensitizes UVA in induction of ODD and reduced repair capacity in MC; 2) the reduced repair capacity for ODD contributes to the high melanoma incidence in XPA patients.

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 2986.
Abstract 2991: Glucose deprivation induces Chk1 degradation through the ubiquitin-proteasome pathway and defective checkpoint response to replication blocks
Authors: Kim Ae Jeong , Kim Hyun-Ju , Jee Hye Jin , Bae Yoe-Sik , Yun Jeanho
Published: February 2011

Chk1 is a key regulator for DNA replication checkpoint and preservation of genomic integrity. Previous studies showed that reduction of Chk1 function leads to defect in checkpoint response and closely associated to tumorigenesis. Here, we found that Chk1 protein is rapidly degraded upon glucose deprivation while its mRNA level is not changed. The glucose deprivation-induced Chk1 degradation is observed in various cancer cell lines as well as human normal fibroblast therefore appears to be a universal phenomenon in mammalian cells. Specific proteasome inhibitor blocks glucose deprivation-induced degradation of Chk1, and the ubiquitination of Chk1 is induced, indicating that the proteasome-ubiquitin pathway mediates the degradation of Chk1. Glucose deprivation-induced Chk1 degradation was not affected by AMPK inhibitor compound C or antioxidant NAC and GSH treatment. Instead, we found that Chk1 phosphorylation at Ser317 and Ser345 site were important step for degradation of Chk1 in response to glucose deprivation. In glucose deprivation condition, cells showed defective checkpoint response to replication stresses, camptothecin (CPT) and hydroxyurea (HU) treatment. Taken together, our results suggest that Chk1 function is suppressed through the ubiquitin-mediated proteolysis in glucose deprivation condition and thereby results in inactivation of proper checkpoint function. Glucose deprivation-induced Chk1 degradation could cause defect in maintaining DNA integrity and may contribute to tumor development in tumor microenvironment.

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 2991.
Abstract 3064: HPP1 tumor suppression and JAK-STAT signaling
Authors: Elahi Abul , Hernandez Jonathan M. , Shibata David
Published: February 2011

Introduction:

HPP1 is a putative tumor suppressor gene that is epigenetically silenced in various tumor types including colorectal cancer. We have previously reported that the ectopic expression of HPP1 results in the upregulation of STAT1, STAT2 and a number of interferon-inducible genes, and that activation of STAT1 is critical for HPP1's growth suppressive functions. We have sought to comprehensively evaluate alterations and the importance of the JAK-STAT signaling axis as they relate to HPP1 overexpression.

Methods:

Full-length HPP1 was amplified and cloned into the pcDNA3.1 expression vector which was then stably transfected into the HCT116 colon cancer cell line. Western Blot analyses were performed to assess both expression and activation for STAT1, STAT2, STAT3, JAK1, JAK2, JAK3 and TYK2 in HPP1 transfectants and empty vector controls. Functional STAT1 and STAT2 promoter binding were quantified using luciferase reporter plasmids containing ISRE-(Interferon Stimulated Regulatory Element) and GAS-(Gamma Activated Site) promoter elements.

Results:

The overexpression of HPP1 resulted in increased expression and activation of STAT1 and STAT2. Overexpression of HPP1 was associated with significant increases in both STAT1:STAT1 (p=0.007) and STAT1:STAT2 (p=0.036) binding, suggesting HPP1 mediates tumor suppression via association with Type II-like (gamma) and Type I-like (alpha) interferon pathways. Furthermore, additional corresponding dose-dependent inductions of STAT1 and STAT2 activation were achieved by treatment of HPP1 transfectants with interferon gamma and alpha. In contrast to STAT1 and 2, forced expression of HPP1 resulted in a downregulation of both STAT3 total expression and activation. HPP1 transfectants demonstrated increases in expression and activation of JAK1, JAK2 and JAK3, as well as a reduction in levels of TYK2 and phosphoTYK2.

Conclusion:

Activation of JAK1, 2 and 3 likely contribute to the upregulation and phosphorylation of STAT1 and STAT2 which in turn, result in the activation of Type I- and Type II-like interferon-inducible elements and their growth suppressive effects. Moreover, we demonstrate a reciprocal abrogation of the oncogenic STAT3 and its associated dominant kinase TYK2. HPP1 appears to mediate tumor suppression via modulation of JAK-STAT-interferon pathways.

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 3064.
Abstract 3079: Loss of β2-spectrin may lead to the activation of telomerase reverse transcriptase (TERT) and hepatocellular cancer formation
Authors: Jiao Zhongxian , Shukla Sanjeev , Kumar Gyanendra , Yao Wenguo , Cao Hong , Jogunoori Wilma SR , Yao Zhixing , Mishra Lopa , Mishra Bibhuti
Published: February 2011

Background and Aims: Telomerase is a specialized reverse transcriptase (TERT) that synthesizes repeat DNA sequences at telomeres- the specialized ends of chromosomes is suppressed in normal cells by multiple proteins that include TGF-β and Smad3 resulting in the progressive shortening of telomeres with each cell division, ultimately leading to chromosomal instability and cellular replicative senescence or growth arrest. Emerging evidence indicates that β2-spectrin (β2SP), a Smad3/Smad4 adaptor protein required for TGF-β signaling, is a powerful tumor suppressor. β2SP+/−, β2SP+/−/Smad3+/− and β2SP+/−/Smad4+/− mice dramatically develop Hepatic cancers. Because TERT is markedly activated in β2SP+/−/Smad3+/− hepatocellular cancer tissues compared to Smad3−/− tissues, we hypothesized that β2SP interaction could be involved in the interaction with Smad3 to suppress TERT expression in normal tissues, and the loss of β2SP may lead to telomerase gene activation resulting in HCC. Results: We tested human TERT (hTERT) expression levels in several HCC cell lines that have different levels of β2SP. hTERT expression levels negatively correlate with β2SP by Western Blot analysis. Loss of β2SP in β2SP+/− and β2SP−/− mouse embryonic fibroblasts (MEFs) significantly activated mTERT expression. Co-transfection of a β2SP expression plasmid and hTERT promoter-luciferase construct significantly inhibited the hTERT promoter in β2SP-deficient SNU-398 cells. Depletion of Smad3 by in vitro RNAi and the expression of hTERT-luciferase in Smad3 depleted cells upon co-transfection with Smad3 and/or β2SP expression plasmids suggest that both Smad3 and β2SP are required for the suppression of hTERT. Furthermore, chromatin immunoprecipitation (ChIP) assay suggests binding of Smad3/β2SP protein to hTERT promoter. Conclusions: Taken together our data suggest that divergent pathways converge on β2SP and Smad3 for the regulation of TERT. Activation of the TGF-β signaling pathway with suppression of TERT provides a strong strategy for generating targeted therapeutics to these lethal human cancers.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 3079.
Abstract 3080: Functional studies of a cell cycle and angiogenesis-related candidate tumor suppressor gene, Mirror image polydactyly 1, in nasopharyngeal carcinoma
Authors: Cheung Arthur Kwok Leung , Lung Hong Lok , Ko Josephine Mun Yee , Lung Maria Li
Published: February 2011

Background and aims: Nasopharyngeal carcinoma (NPC) is a cancer with an especially high incidence in Southern China. We performed functional complementation studies to confirm and map critical regions on chromosome 14 associated with its tumor-suppressive ability. An interesting candidate tumor suppressor gene (TSG), Mirror image polydactyly 1 (MIPOL1) was identified. Previously this gene has only been reported to be associated with a genetic developmental disorder. Its contribution to cancer and its functional role in NPC was, therefore, investigated. Methods: A tetracycline-inducible system was used to obtain MIPOL1-expressing clones. A wild-type MIPOL1 gene was transferred into a NPC cell line, HONE1-2. Functional studies such as in vivo nude mouse tumorigenicity, HUVEC tube formation, and cell cycle analysis assays were used to investigate the function of MIPOL1. Results: MIPOL1 re-expression can suppress tumor growth in vivo and induce cell cycle arrest through increasing p21(WAF1/CIP1) and p27(KIP1) expression. Furthermore, expression of MIPOL1 can inhibit angiogenesis in the tube formation assay. Functional pathways were studied by detection of change in expression levels of different angiogenesis-related proteins in cell lysates and conditional medium of those stable clones. Conclusions: An interesting candidate TSG, MIPOL1, was identified. Functional studies confirm that MIPOL1 can suppress tumor growth in vivo. It can induce cell cycle arrest through the p21(WAF1/CIP1) and p27(KIP1) pathways. MIPOL1 can also inhibit angiogenesis, and this further confirms its importance in tumor suppression. Changes in expression of different angiogenesis-related proteins were observed. MIPOL1 is a good candidate tumor suppressor gene in NPC and warrants further study.

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 3080.
Abstract 3089: Heterogenous high level HER-2 amplification in a small subset of colorectal cancers
Authors: Marx Andreas Holger , Simon Ronald , Sauter Guido
Published: February 2011

HER-2 is the molecular target for antibody-based treatment of breast cancer (trastuzumab). The potential benefit of anti-HER-2 therapy is currently investigated in several other HER-2 amplified cancers. For example, trastuzumab was recently shown to be effective in HER-2 positive gastric cancer. To address the potential applicability of anti-HER-2 therapy in CRC, tissue microarray (TMA) sections and colorectal resection specimens of 1851 CRC were analyzed for HER-2 overexpression and amplification using FDA approved reagents for immunohistochemistry and fluorescence in situ hybridization. HER-2 amplification was seen in 2.5% and HER-2 overexpression in 2.7 % of 1439 interpretable CRC. Amplification was often high level with HER-2 copies ranging from 4 to 60 per tumor cell and was strongly related to protein overexpression. HER-2 amplification and overexpression were unrelated to histological tumor type, tumor localization, grading, pT, pN, pM or survival. As heterogeneity of drug target expression could represent a major drawback for targeted cancer therapy we next studied HER-2 heterogeneity in selected cases. Extensive evaluation of all available large sections from patients with HER-2 positive CRC revealed heterogenous findings in 3 of 4 cases.

In summary, high level HER-2 amplification occurs in a small fraction of CRCs. Heterogeneity of amplification may limit the utility of anti HER-2 therapy in some of these tumors and therefore, adequate clinical trials are needed to further evaluate this approach.

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 3089.