bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 5453: Drug transport in peritoneal tumors during intraperitoneal therapy – evaluation by computational model
Authors: Gao Yue , Guo Peng , Lu Ze , Tsai Max , Wientjes M. Guillaume , Au Jessie L-S.
Published: June 2012

Clinical studies have established that the efficacy of intraperitoneal paclitaxel therapy is dependent on the tumor size, producing survival advantage in patients with small tumors (<1 cm diameter) but not in patients with larger tumors. This study was to investigate the mechanisms of this observation. We developed computational models to examine the effects of tumor size, drug binding (to extracellular proteins), tumor heterogeneity, and drug absorption on drug interstitial transport. The required model parameters were obtained from the literature. The models were used to simulate the drug penetration in small (0.3 cm) and larger (1 cm) tumors. Model performance was evaluated by comparing the simulated results to lab-generated experimental data using paclitaxel in mice bearing peritoneal metastases of ovarian tumors. The experiments measured drug concentration vs tumor penetration depth using autoradiography. The validated models were then used to generate penetration kinetic data for tumors of different sizes. The simulated penetration kinetics was subsequently compared to the pharmacodynamic data obtained from the literature (i.e., the C×T50 that produced 50% inhibition of tumor growth). The penetration kinetic models described the interstitial paclitaxel transport by both diffusion and convection, and the drug absorption into tumor vasculature by diffusion. The model-predicted concentration-penetration depth profiles were in general agreement with the experimental profiles (average deviation of 13.7%), indicating good model performance. The simulated drug C×T exceeded the C×T50 value at depth of up to 3 mm (from all sides of the outer tumor perimeter), indicating that for a spherical tumor of 1 cm diameter, 6.4% of the tumor (volume) would receive less than the therapeutic exposure, C×T50. Additionally, doubling the tumor diameter to 2 cm increased the subtherapeutic tumor volume fraction by nearly 5-times (34.3%). We have developed computational models to depict interstitial drug transport in peritoneal tumors during intraperitoneal therapy. These models provide quantitative measures of the effect of tumor size on local drug exposure for the tumor, and have the potential of predicting the tumor pharmacokinetics-pharmacodynamics for a given treatment.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 5453. doi:10.1158/1538-7445.AM2011-5453
Abstract 5477: Multiple BH3 mimetics antagonize anti-apoptotic MCL1 by inducing the endoplasmic reticulum stress response and upregulating the BH3-only protein NOXA
Authors: Albershardt Tina C. , Salerni Bethany L. , Soderquist Ryan S. , Bates Darcy J P , Pletnev Alexandre A. , Eastman Alan R.
Published: June 2012

Many small molecules have been designed or discovered that mimic the binding of BH3-only proteins to the hydrophobic groove of anti-apoptotic BCL2 proteins and thus have potential as anticancer agents. For example, ABT-737 preferentially binds and inhibits BCL2 and BCL-XL but not MCL1. It is generally believed that specific inhibitors of anti-apoptotic BCL2 proteins should induce apoptosis in a BAX/BAK-dependent manner. While this is true for ABT-737, many other purported BH3 mimetics have been shown to kill cells in a BAX/BAK-independent manner leading to the conclusion that they function through alternative undefined targets. The selectivity of these BH3 mimetics for BCL2, BCL-XL, or MCL1 has been established in vitro; whether they inhibit these proteins in cells has not been rigorously investigated. In this study, we used a panel of leukemia cell lines to assess the ability of seven putative BH3 mimetics to affect the interaction of BCL2 family members in a cell-based system. We show that ABT-737 is the only BH3 mimetic that inhibits BCL2 in cells as assessed by displacement of BAD from BCL2. The other six BH3 mimetics activated the endoplasmic reticulum (ER) stress response and induced ATF3 resulting in induction of NOXA which binds to and inhibits the anti-apoptotic MCL1 protein. The fact that 6 different compounds, all of which are thought to be BH3 mimetics, can induce ER stress suggests that they may interact with a common target although whether this is a BCL2 family member remains to be established. In most cancer cells, inhibition of either BCL2/X or MCL1 does not acutely induce apoptosis. However, by combining two BH3 mimetics, one that inhibits BCL2 and one that induces NOXA, apoptosis is induced within 6 h in a BAX/BAK-dependent manner. As MCL1 is a major mechanism of resistance to ABT-737, these results suggest a novel strategy to overcome this resistance. In summary, these results identify a novel signaling pathway through which many BH3-mimetics inhibit MCL1 and suggest the potential use of these agents as adjuvants in combination with various chemotherapy strategies.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 5477. doi:10.1158/1538-7445.AM2011-5477
Abstract 5486: Combined targeting of the PI3K and MAPK pathways is required for efficacy in treating colorectal cancer of the wild and mutant types
Authors: Hong Seung-Woo , Shin Jae-Sik , Jin Dong-Hoon , Hong Yong-Sang , Lee Jae-Lyun , Ryu Min-Hee , Kim Tae-Won
Published: June 2012

The KRAS oncogene is commonly mutated in human colon cancer. The downstream pathways of mutant KRAS, including the RAF/MEK/ERK, mitogen-activated protein kinase (MAPK), and phosphatidylinositol 3-kinase (PI3K)-AKT signaling are indispensible in order to understand how to pharmacologically target them when treating colon cancer with the KRAS mutant. However, the heterogeneous responses of these effector pathways remain unclear. Recent studies have indicated that mutational activation of PI3K (PIK3CA) in KRAS mutant tumor cells induces resistance to the inhibition of MEK, one of the MAPK signal cascades. Wild-type p53 also suppresses the oncogenic potential of the MAPK pathway. Our study shows that bortezomib inhibits the PI3K-AKT pathway and that nutlin-3A used as a p53-inducing agent blocks the MAPK pathway. The high doses of bortezomib induced apoptosis through complete suppression of AKT phosphorylation in KRAS and PI3K mutant colon cancer cells. Treating patients using high doses of nutlin-3A resulted in apoptosis by inducing p53 phosphorylation in colon cancer cells with wild-type p53. We also showed that the combination of bortezomib and nutlin-3A exhibited a synergistic effect on KRAS mutant colon cancer cells with PI3K mutant and wild-type p53, whereas there are no combined effect in KRAS mutant colon cancer cells with the p53 mutant. In addition, bortezomib and nutlin-3A exhibited combined effect in KRAS wild-type colon cancer cells with PI3K mutant and wild-type p53, although not in p53 mutant cells. We consistently noted that treatment with bortezomib and nutlin-3A after p53 silencing using small, interfering RNA (siRNA) in p53 wild-type colon cancer cells, resulted in a decrease of the populations of dead cells. Therefore, these results suggest that a combination of bortezomib and nutlin-3A can overcome the heterogeneous responses of the effector pathway in colon cancer with KRAS mutant; they also provide a new basis for the clinical testing of PI3K- and MAPK-targeted therapies.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 5486. doi:10.1158/1538-7445.AM2011-5486
Abstract 552: Targeting brain tumors with PLX3397, an inhibitor of the CSF-1 receptor kinase
Authors: West Brian L. , Tsai James , Nicolaides Theodore , Wong Bernice , Nguyen Hoa , Marimuthu Adhirai , Ibrahim Prabha , Hirth Peter , Bollag Gideon
Published: June 2012

Cancer growth in the brain incites a neuroinflammatory response that becomes a defining feature of the brain tumor microenvironment. Microglia and macrophages provide important functions that support the invasiveness of glioblastoma. Other cancer types that become metastatic to brain also rely on the microenvironment to support angiogenesis.

PLX3397 is a potent inhibitor of the transmembrane tyrosine kinase receptor for colony stimulating factor-1 (CSF-1R). The CSF-1R is required for the differentiation and activation of microglia and macrophages. Oral administration of PLX3397 to mice at 20 mg/kg qd significantly reduces the microglia/macrophage marker, Iba1, as determined by western blotting.

PLX3397 penetrates the blood-brain barrier, as determined through pharmacokinetic analysis, with brain levels reaching substantial fractions of the concurrent plasma levels. PLX3397 is highly bound to plasma albumin, and therefore the levels attained in the brain likely affect Iba1 levels through a local inhibition of brain microglia and macrophages, although a peripheral effect may also contribute.

Culture of glioblastoma cell lines including U87, and treatment with chemotherapeutic agents or radiation, was found to cause a 4-fold elevation of the two CSF-1R ligands, CSF-1 and IL-34, as quantified by QPCR. This indicates that glioma cells can recruit and stimulate microglia and macrophages, and that current standard therapies likely exacerbate this stimulation. Other cancer types that are known to form metastases to brain, including melanoma and breast cancer, show similar abilities to produce these cytokines in response to standard therapies.

The rat 9L glioblastoma line forms an aggressive tumor when tested as an orthotopic model in syngeneic Fisher rats. Seven days after implantation, PLX3397 was administered via rodent chow for 14 days, reducing the tumor growth by 44% as determined by MRI.

These results provide preclinical evidence that PLX3397 may show a clinical benefit in brain cancers, either as a single agent or in combination with standard chemo- or radiation therapies. PLX3397 is nearing completion of a successful Phase 1 dose-escalation safety trial in solid tumor cancer patients.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 552. doi:10.1158/1538-7445.AM2011-552
Abstract 5522: Increase of Th1/Treg ratio in peripheral blood of breast cancer patients with autologous formalin-fixed tumor vaccine
Authors: Kuranishi Fumito
Published: June 2012

Introduction: Autologous formalin-fixed tumor vaccine (AFTV) containing formalin-fixed and/or paraffin-embedded tumor fragments is able to induce tumor specific CTL and suppresses recurrence of hepatocellular carcinoma after resection (Clin Cancer Res 2004; 10: 1574-9). We have used delayed-type hypersensitivity (DTH) test as a parameter of cellular immune response. We also found that slight but consistent population change has occurred in peripheral blood T lymphocytes after AFTV treatment.

Method: Thirty two breast cancers were operated in our hospital. AFTV was injected intradermally. DTH response to the tumor fragments without any adjuvant was determined if erythema was 10mm or more.

Results: After operation, standard chemotherapy, and enough time have passed to recover immunological function, we examined change of peripheral blood T-cell population in 32 cases with breast cancer. Among them, 27 cases turned DTH response from negative to positive after AFTV injection. In these patients, WBC counts increased 1.11 times; lymphocytes, 1.09 times; Th1 in CD4+ T cells, 1.07 times; regulatory T cells (Treg) in CD4+ T cells, 0.95 times, and Th1/Treg ratio, 1.17 times (statistically significant, 95%CI was 1.060-1.284).

Conclusion: AFTV probably strengthen the cellular immune response against cancer by improving Th1/Treg ratio in peripheral blood.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 5522. doi:10.1158/1538-7445.AM2011-5522
Abstract 5548: Comparison of gene expression profile in chromate transformed BEAS-2B cells
Authors: Hong Sun , Clancy Harriet A. , Kluz Thomas , Zavadil Jiri , Costa Max
Published: June 2012

Background: Hexavalent chromium [Cr(VI)] is a potent human carcinogen. Occupational exposure has been associated with increased risk of respiratory cancer. Multiple mechanisms have been shown to contribute to Cr(VI) induced carcinogenesis, including DNA damage, genomic instability, and epigenetic modulation, however, the molecular mechanism and downstream genes mediating chromium's carcinogenicity remain to be elucidated.

Methods/Results: We established chromate transformed cell lines by chronic exposure of normal human bronchial epithelial BEAS-2B cells to low doses of Cr(VI) followed by anchorage-independent growth. These transformed cell lines not only exhibited consistent morphological changes but also acquired the ability to form tumors in nude mice. Interestingly, the gene expression profiles of six Cr(VI) transformed cell lines were remarkably similar to each other yet differed significantly from that of either control cell lines or normal BEAS-2B cells. A total of 409 differentially expressed genes were identified in Cr(VI) transformed cells compared to control cells. Genes related to cell-to-cell junction were upregulated in all Cr(VI) transformed cells, while genes associated with the interaction between cells and their extracellular matrices were down-regulated. Additionally, expression of genes involved in cell proliferation and apoptosis were also changed.

Conclusion: This study is the first to report gene expression profiling of Cr(VI) transformed cells. The gene expression changes across individual chromate exposed clones were remarkably similar to each other but differed significantly from the gene expression found in anchorage-independent clones that arose spontaneously. Our analysis identified many novel gene expression changes that may contribute to chromate induced cell transformation, and collectively this type of information will provide a better understanding of the mechanism underlying chromate carcinogenicity.

(This work was supported by grant numbers ES000260, ES014454, ES005512, ES010344 from the National Institutes of Environmental Health Sciences, and grant number CA16087 from the National Cancer Institute)

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 5548. doi:10.1158/1538-7445.AM2011-5548
Abstract 5557: Steady DNA adduct accumulation by dibenzo[a,l]pyrene implants
Authors: Jeyabalan Jeyaprakash , Aqil Farrukh , Ravoori Srivani , Vadhanam Manicka V. , Gupta Ramesh C.
Published: June 2012

The past and current trends in determining the DNA-damaging and carcinogenicity potential of environmental toxicants rely largely on treatment of rodents with single or multiple bolus doses. To simulate the human scenario where the exposure is generally continuous to low doses, we have developed polymeric implants embedded with carcinogens. When grafted subcutaneously, polymeric implants provide continuous (“24/7”) low dose exposure. In this study we report the effects of sustained low doses of a highly potent environmental carcinogen, dibenzo[a,l]pyrene (DBP) on DNA adduct accumulation. Different size DBP implants (10 – 20 mm long, 1.4 – 2.4 mm dia; 5% DBP load) were tested first in a pilot study using female A/J mice to optimize the implant surface area. Two 20-mm implants (1.4 mm dia), which produced maximal lung DNA adducts, were used subsequently. Groups of female A/J mice (n = 4 – 6) were grafted with sham or DBP implants. For comparison, animals were also treated in parallel with a bolus carcinogenic dose of DBP intraperitoneally (6 mg/kg) or vehicle alone. Animals from both the treatment groups were euthanized at different time intervals and selected tissues were collected. Analysis of the target (lung) DNA adducts by 32P-postlabeling showed qualitative identical adduct patterns by the two routes of administration; the sham treatments showed no detectable adducts. As expected, the bolus dose treatment resulted in higher DNA adducts (in adducts /109 nucleotides) (72 ± 18) compared with the implant group (33 ± 17) one week post-treatment. However, 3 weeks later, adduct levels in the implant group increased (54 ± 17) but a significant declined occurred in the i.p treatment group (19 ± 13). The adduct levels after 4 weeks in the implant group (66 ± 19) were somewhat higher than the 3 week group, suggesting that the adduct levels plateaued. The steady accumulation of DNA adducts was consistent with continuous release of DBP from the implant (about 10 µg/day based on in vitro release). The study is ongoing to determine if the low-dose continuous exposure which provides steady accumulation of DNA adducts in the target tissue will be tumorigenic. In summary, the steady-state adduct level reflect human exposure scenario and this approach will be ideal to determine both carcinogenicity and biological/pathological changes due to low-dose exposure as well as for screening potential chemopreventive agents. This exposure system has been used to determine efficacy of chemopreventive agents (accompanying abstracts by Aqil et al.; Gupta et al.) (Supported from CA-118114, KLCRP and Agnes Brown Duggan Endowment).

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 5557. doi:10.1158/1538-7445.AM2011-5557
Abstract 5564: Lack of efficacy of metformin in several standard prevention models: Methylnitrosourea rat mammary (ER+), MMTV-Neu/p53 mouse mammary (ER−) and the Min mouse colon
Authors: Lubet Ronald A. , Clapper Margie , Bode Ann , Steele Vernon , Grubbs Clinton
Published: June 2012

Metformin, an anti-diabetic drug, activates AMP-activated protein kinase (AMPK), and has generated considerable interest as a potential preventive agent for a variety of cancers. This interest is based both on epidemiologic studies showing that diabetics treated with metformin have a lower incidence of a variety of cancers, and on mechanistic considerations arguing that activation of AMPK is likely to be relevant to cancer treatment and prevention. The preventive efficacy of metformin was examined in three commonly employed in rodent prevention models of breast and intestinal cancers. Treatment of female Sprague-Dawley rats at 50 days of age with a single dose of MNU (75 mg/kg BW) resulted in the development of multiple ER+ mammary cancers. This model has been highly responsive to a wide variety of agents or hormonal alterations that affect ER+ tumors in humans (SERMs, aromatase inhibitors, pregnancy, and ovariectomy). Metformin was administered by gavage (7x/week) at either 150 or 50 mg/kg BW/day; beginning seven days after MNU treatment and continuing for the duration of the study. Metformin failed to decrease mammary cancer incidence and, in fact, increased tumor multiplicity in this model by approximately 35%. In addition, the ability of metformin to inhibit mammary cancer in MMTV-Neu/p53 KO mice (which spontaneously develop ER− cancers) was evaluated. In this study, metformin was administered in the diet at a dose level of 1500 mg/kg diet. Initial supplementation of the diet with this agent began when the mice were 60 days of age, and continued for 10 months. This study similarly showed no efficacy of metformin (average tumors/mouse: 2.7 in both controls and metformin-treated mice). Finally the effect of metformin was examined in the Min model of intestinal neoplasia, in which mice have a germline APC mutation. Again, we failed to observe any efficacy of metformin. In contrast, naproxen (a non-specific NSAID) was highly effective in this model when used as a positive control. Thus, these initial studies failed to detect any chemopreventive efficacy of metformin in three commonly employed prevention models. One major caveat to these studies is that the animals were not diabetic nor were they administered an altered diet containing high fat or carbohydrates. Supported by NCI contract number HHSN261200433001C.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 5564. doi:10.1158/1538-7445.AM2011-5564
Abstract 5574: mTOR is a target for omega-3 fatty acid modulation of prostate cancer progression
Authors: Apte Shruti A. , Cavazos David , Hursting Stephan , Nogueira Leticia , deGraffenried Linda A.
Published: June 2012

Prostate cancer is the second leading cause of cancer related deaths in men. The primary obstacle in effective treatment of prostate cancer is the progression of the disease from a hormone-dependent to a hormone-independent state. Previous studies indicate that activation of the mammalian Target of Rapamycin (mTOR) signaling pathway may be involved in progression of prostate cancer to androgen independence. Recent data indicate that the combination of androgen deprivation with mTOR inhibition provides an additive anti-tumor effect in vivo. mTOR activity is regulated by both growth factors and nutrients, suggesting that certain dietary interventions may have anti-cancer effects through regulation of mTOR. Epidemiological studies indicate an inverse relation between dietary intake of omega-3 fatty acids and prostate cancer risk. Omega-3 fatty acids have been shown to inhibit prostate cell growth both in vitro and in vivo. Preliminary data from our laboratory demonstrated that treatment of LNCaP prostate cancer cells with omega-3 fatty acids, specifically docosahexaonoic acid (DHA), delayed development of androgen independence in vitro. This delay correlated with a decrease in protein expression of downstream targets of mTOR regulation, including phosphorylated S6, Bcl-2, and cyclin D. We hypothesize that omega-3 fatty acids may prevent prostate cancer progression to a hormone independent phenotype in part through modulation of mTOR. To test this hypothesis, we established stable transfectant LNCaP cell lines that express a constitutively active mTOR. These clones displayed less sensitivity to hormone deprivation, resembling the response observed in our previously generated hormone refractory LNCaP cell line. Importantly, these clones with constitutively active mTOR also showed resistance to the inhibitory effects of DHA. Ongoing studies are using these clones to determine if omega-3 fatty acids mediate their effect on mTOR in an Akt-independent manner to delay progression of prostate cancer to a hormone refractory phenotype. We will investigate alternative pathways through which mTOR activity is modulated in prostate cancer signaling, These studies indicate that mTOR is critical for cellular response to hormone ablation, and that mTOR may be a viable target for delaying progression to a hormone refractory disease.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 5574. doi:10.1158/1538-7445.AM2011-5574
Abstract 561: Tumor-associated fibroblast-induced head and neck squamous cell carcinoma invasion can be abrogated by c-Src and c-Met inhibition
Authors: Shi Huifang , He Gouqing , Joyce Sonali , Thomas Sufi M.
Published: June 2012

Purpose: Mortality from head and neck squamous cell carcinoma (HNSCC) is usually associated with locoregional invasion of the tumor into vital organs including the airway. There are currently no treatments that abrogate HNSCC tumor invasion. HNSCC tumors are frequently associated with reactive fibroblasts. Our preliminary data demonstrate that stromal fibroblasts in the vicinity of the tumor induce phosphorylation of c-Src and induce HNSCC invasion. We reported that tumor-associated fibroblasts (TAF) secrete HGF that binds to the c-met receptor on HNSCC activating downstream signaling contributing to the invasive phenotype. In addition we have previously reported that c-Src plays an important role in mediating HNSCC invasion. We hypothesize that blocking c-Met and c-Src in HNSCC cells will abrogate TAF induced HNSCC invasion.

Experimental design: Inhibition of c-Met and c-Src was achieved by a combination of small molecule inhibitors and dominant negative approaches. The effect of inhibition of c-Met and c-Src on invasion of HNSCC cells was assessed in an in vitro Matrigel coated transwell invasion assay.

Results: We demonstrate that inhibition of c-Met or c-Src with inhibitors or using dominant-negative constructs attenuated TAF-stimulated HNSCC invasion. Combined inhibition of c-Met and c-Src resulted in further attenuation of HNSCC cell invasion in vitro.Conclusions: These cumulative results suggest that TAF-induced signaling through c-Met and c-Src contribute to HNSCC invasion and that targeting these pathways may be a novel strategy to prevent tumor invasion and metastasis in HNSCC.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 561. doi:10.1158/1538-7445.AM2011-561
Abstract 5615: Global DNA methylation by LUMA predicts breast cancer risk in a population-based study
Authors: Xu Xinran , Gammon Marilie D. , Wetmur James G. , Teiltelbaum Susan L. , Bradshaw Patrick T. , Neugut Alfred I. , Santella Regina M. , Chen Jia
Published: June 2012

Global methylation dysregulation is a hallmark of cancer cells. Global methylation measurement in peripheral blood may be a predictor of cancer risk and prognosis. In this study, we used two independent assays, LUminometric Methylation Assay (LUMA) and LINE-1 methylation by pyrosequencing, to assess the global methylation content in the peripheral blood DNA from the Long Island Breast Cancer Study Project, a population-based case-control study. We examined the association between global methylation levels and: 1) the risk of developing breast cancer among 1055 cases and 1101 controls using logistic regression models; 2) the risk of mortality among breast cancer cases using Cox proportional hazards models; and 3) one-carbon metabolism genetic polymorphisms and dietary intake among controls using ANOVA. LUMA methylation levels were higher among cases (mean: 57.3%) than among controls (mean: 52.4%; p<0.001). Compared to women in the lowest quintile of LUMA methylation, those in the highest quintile had a 2.41-fold increase in the risk of developing breast cancer (95% CI: 1.83-3.16; p for trend < 0.0001). Risk was strongest for in situ breast cancer (OR: 6.18; 95% CI: 3.34-11.43), although the estimate is based on small numbers; but the association did not vary by other tumor characteristics, life-style or several established breast cancer risk factors. Among cases, there was an indication that high LUMA levels were associated with reduced breast cancer-specific mortality. Among controls, LUMA levels were associated with two SNPs in the one-carbon metabolism pathway, MTHFR C677T (p=0.001) and MTRR A66G (p=0.018), but not with dietary intake of one-carbon related nutrients. No association was observed between LINE-1 methylation and breast cancer risk, breast cancer-specific mortality, one-carbon metabolism SNPs or nutrients, or LUMA methylation. Our results suggest that LUMA methylation levels in peripheral blood DNA are associated with breast cancer development and progression.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 5615. doi:10.1158/1538-7445.AM2011-5615
Abstract 587: B-Raf status predicts response to pharmacological activation of p53 in melanoma
Authors: Lee John T. , Brafford Patricia A. , Halloran Molly B. , Schultz David C. , Herlyn Meenhard
Published: June 2012

The formulation of highly-potent and specific inhibitors of the MAPK pathway has yielded several promising candidates and these are currently under advanced clinical development; however, early data suggests that inhibition of the MAPK pathway will not be sufficient to elicit sustained tumor regression in malignant melanoma. Thus, other pathways likely need to be therapeutically exploited to achieve sustained responses in melanoma patients. Because the tumor suppressor protein p53 is functional, yet inactive, in nearly 100% of melanomas, we sought to identify novel pharmacological activators of p53 in melanoma. To accomplish this goal, we employed a high-throughput screening strategy that identified hycanthone, a compound previously characterized for anti-schistosomal activity, as a specific activator of p53 function. In vitro characterization of hycanthone demonstrated that it activates the p53-transcriptional response leading to cell cycle arrest and subsequent apoptosis in a panel of melanoma cell lines harboring wild-type p53; these effects are largely absent in isogenic cells expressing p53 shRNA or alternative lines expressing mutant p53. Screening of a substantial panel of cell lines revealed that activation of p53 initiated anti-melanoma effects exclusively in cells that expressed mutant Braf, indicating that activated MAPK signaling may serve as a correlate to predict response to pharmacological activators of p53 in melanoma. However, additional experimentation has demonstrated that, instead, it is the presence of mutations in Braf, rather than the resultant MAPK activity, that predicts response to p53 activation. Studies investigating the mechanistic details governing this biological phenomenon are ongoing. Collectively, our data indicate that reactivation of p53 in melanoma, like multiple other tumors, can elicit an anti-tumor phenotype; however, this response is negatively modulated by the expression of mutant Braf, which would suggest that patients should be prospectively genotyped to identify potential responders to p53 reactivators.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 587. doi:10.1158/1538-7445.AM2011-587
Abstract 594: MDM2 inhibition by MI-219 elicits differential molecular effects in wild-type p53 lymphoma cells
Authors: Sosin Angela M. , Yang Dajun , Mohammad Ramzi M. , Al-Katib Ayad
Published: June 2012

Mutations in TP53 occur in 50% of all cancers but are far less common in hematological malignancies. The activity of wild-type p53 (wt-p53) is frequently compromised in lymphomas by overexpression of MDM2. Small-molecule inhibitors (SMIs) that can disrupt the MDM2-p53 interaction and restore p53 function may be an attractive therapeutic strategy. Although response to MDM2 inhibition has previously been determined to greatly depend on p53 status, p53 functional consequences are not fully understood in the presence of MDM2 SMIs. We recently demonstrated striking growth inhibition of two different classes of MDM2 SMIs: Nutlin-3; a cis-imadiazole and MI-219; a spiro-oxindole. Growth inhibition was seen in wt-, but not mutant-, p53 lymphoma cells and did not affect MDM2 E3 ligase activity.

In this study, we report that MDM2 inhibition exerts differential molecular effects in wt-p53 lymphoma cells. We found that wt-p53 cell lines, FSCCL and KM-H2, are sensitive to MDM2 inhibition in a time- and dose-dependent manner. Moreover, MI-219 showed greater potency compared to analogous concentrations of Nutlin-3. MI-219 caused more pronounced cell cycle arrest of both cell lines in G0/G1 over a 72 hour time period. Treatment stabilized and activated p53 as well as upregulated p21 and MDM2 protein levels. MG132 and cycloheximide treatments were performed in the presence or absence of MI-219 to determine whether the increase in p53 was due to dissociation from MDM2 and not increased degradation or stabilization. Co-immunoprecipitation confirmed MDM2 SMI disruption of the MDM2-p53 interaction. There was clear evidence of apoptosis in FSCCL, but surprisingly not in KM-H2, as indicated by TUNEL/PI staining (54.39% ± 4.78 vs. 1.32% ± 0.52 after 24 hours). Additionally, apoptosis markers were induced at both mRNA (p53AIP1) and protein levels (caspase-3 and PARP cleavage) after exposure to MI-219 in FSCCL compared to KM-H2. The molecular mechanisms by which MDM2 SMIs exert this differential effect are currently under investigation.

Our data presents the preclinical structure for further exploration of MI-219 as a therapeutic approach in the treatment of wt-p53 lymphomas. However, based on our findings, we conclude that additional insights to p53 biology are necessary to maximize their therapeutic potential from preclinical to clinical development.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 594. doi:10.1158/1538-7445.AM2011-594
Abstract 609: Frondoside antagonizes the prostaglandin E receptor EP4 and inhibits breast tumor metastasis
Authors: Ma Xinrong , Kundu Namita , Collin Peter , Fulton Amy M.
Published: June 2012

Sea cucumber has been used as a folk medicine for many conditions and recently antitumor activities have been described. Frondoside A, a triterpenoid glycoside isolated from the sea cucumber Cucumaria frondosa, as well as the related compound Frondanol A5 inhibit growth of pancreatic, colon and breast tumor cell lines in vitro and show activity in a primary prevention model of colon cancer. The cyclooxygenase 2 pathway contributes to growth and progression of many solid tumors by multiple mechanisms. The COX-2 product, prostaglandin E2 (PGE2) contributes to malignancy by acting on a family of four G-protein-coupled receptors (EP1, EP2, EP3, EP4). We have shown that both human and murine breast tumor cell lines express all EP receptors and that EP4 contributes to metastatic potential in a syngeneic murine model of metastatic breast cancer. Other laboratories have also provided evidence that EP4 promotes malignancy but a paucity of effective EP4 antagonists has slowed the development of clinically evaluable EP-targeted compounds. Based on the reported anti-inflammatory properties of Frondoside A, we asked if this compound has EP antagonist properties. We now report the novel finding that Frondoside A is a potent antagonist of EP4 and, to a lesser degree, antagonizes EP2. Frondoside A inhibits the binding of radio-labeled PGE2 to Chem-1 cells expressing EP4 or HEK cells transduced to express EP2. Using EP4-expressing MDA-MD-231 human breast cancer or murine mammary tumor cell line 66.1, we show that EP4-mediated activation of adenylate cyclase is also blocked by Frondoside A indicating both pharmacologic and functional EP4 receptor antagonism. We determined the effect of Frondoside A on metastatic potential of line 66.1 tumor cells. Treatment of 66.1 cells with non-cytotoxic concentrations of Frondoside A prior to i.v. administration of tumor cells into syngeneic Balb/cByJ female mice reduced lung colonizing capacity by 58%. These studies describe a potent metastasis inhibitory activity of Frondoside A and show, for the first time, that this compound may be a potent novel EP4/EP2 antagonist with activity in a model of metastatic breast cancer.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 609. doi:10.1158/1538-7445.AM2011-609
Abstract 61: Integrated analysis of genetic and epigenetic alterations reveals CpG island methylator phenotype associated with clinical outcome of lung adenocarcinoma
Authors: Shinjo Keiko , Kondo Yutaka , Okamoto Yasuyuki , Yokoyama Toshihiko , Usami Noriyasu , Fujii Makiko , Murakami Hideki , Osada Hirotaka , Sekido Yoshitaka
Published: June 2012

Background: Lung cancer is the leading cause of cancer-related death worldwide. While targeted therapy, such as tyrosine kinase inhibitors (TKIs), has been used against the non small cell lung cancers (NSCLCs) patients with epidermal growth factor receptor (EGFR) mutation, not all the patients received benefit from TKIs. Epigenetic alterations have been recognized as one of the important mechanism of NSCLCs. The aim of this study is to clarify the significance of DNA methylation, especially the clinical impacts of CpG island methylator phenotype (CIMP), in NSCLCs. Methods: Using methylated CpG island amplification-microarray (MCAM), a genome-wide DNA methylation analysis, 41 lung adenocarcinomas (AdCas) were analyzed. DNA methylation of newly identified genes from MCAM analysis was further examined in another cohort of 86 AdCas with bisulfate pyrosequencing method. Results: Unsupervised hierarchical cluster analysis revealed that DNA methylation was extensively accumulated in one subgroup (n=4, 9.8%), which may represent CIMP tumors (651 genes vs. 354 genes, P=0.0004). DNA methylation status of newly identified 7 CIMP markers revealed that 8 (9.3%), 12 (14%), and 66 (76.7%) were classified into CIMP-high, CIMP-low, and CIMP-negative tumors, respectively. CIMP-high tumors showed no EGFR mutations and frequent exposure to smoking. In addition, these tumors had worse prognosis than the other tumors (P=0.035), suggesting that CIMP-high tumors have characteristic clinical features, which may represent an alternative mechanism to the EGFR mutation. Treatments of NSCLC cell lines showed that CIMP positive AdCa cell lines are sensitive to DNA demethylating agent regardless of EGFR status. Conclusions: Our data suggest that CIMP in AdCas appears to be a unique subgroup, which has distinguished clinical traits from the other AdCas. Applying DNA demethylating agent to CIMP-high tumors might be a new strategy for the treatment of NSCLCs without EGFR mutation.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 61. doi:10.1158/1538-7445.AM2011-61
Abstract 620: Development of a dual protein farnesyltransferase -geranylgeranyltransferase-I inhibitor with antitumor activity against human cancer cells
Authors: Kazi Aslamuzzaman , Luo Yunting , Berndt Norbert , Fletcher Steven , Cummings Christopher , Lawrence Harshani , Hamilton Andrew D. , Sebti Said M.
Published: June 2012

Many low molecular weight GTPases such as Ras, Ral and Rho require posttranslational farnestylation or geranylgeranylation for mediating malignant transformation. This prompted the development of farnesyltransferase (FT) inhibitors (FTI) and geranylgeranyltransferase-I (GGT-1) inhibitors (GGTI) as potential anticancer agents. However, when cancer cells are treated with FTIs, K-Ras becomes geranylgeranylated suggesting that inhibition of both FT and GGT-1 may be required to inhibit tumors harboring K-Ras mutations. Recently our group has developed a series of dual FT and GGT-1 inhibitors based on an ethylenediamine scaffold. Among these dual inhibitors FGTI-2734 was most potent in vitro (FT IC50 = 250±190 nM and GGT-1 IC50 = 520±90 nM). In human cancer cells FGTI-2734 inhibits potently HDJ-2 farnesylation, Rap 1A geranylgeranylation and K-Ras prenylation. Furthermore, FGTI-2734 inhibits the phosphorylation of Erk1/2, Akt and S6K, induces p27 accumulation and inhibits potently tumor cell growth. Finally, FGTI-2734 significantly reduces survivin protein levels, and reduction of survivin levels is associated with induction of apoptosis. Thus, this single molecule with dual FT and GGT-1 inhibitory activities may have distinct advantage over selective FTIs and GGTIs and warrants further advanced pre-clinical studies.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 620. doi:10.1158/1538-7445.AM2011-620
Abstract 626: Specific targeting of cancer cells with RNA aptamers
Authors: Cerchia Laura , Esposito Carla Lucia , Catuogno Silvia , Iaboni Margherita , Draetta Giulio , Condorelli Gerolama , de Franciscis Vittorio
Published: June 2012

A great promise in developing specific molecular probes for disease biomarker discovery and for diagnostic and therapeutic applications is recently represented by the intact cell-based SELEX (Systematic Evolution of Ligands by EXponential enrichment) strategy that allow to select nucleic acid aptamers against living cells. Indeed, using cell-SELEX to target proteins expressed on the cell surface permits to develop aptamers that are able to discriminate between even closely related target cells. This strategy has the advantage of a direct selection of ligands without prior knowledge of the target molecules and enables the identification of aptamers that bind large cell surface-specific markers, in their native conformation.

Recently, by coupling a differential whole-cell SELEX protocol to human glioma and NSCLC cell lines we addressed the possibility to isolate aptamer molecules that may target cancer specific cell surface bound proteins.

We isolated a set of 2’fluoro-pyrimidines modified RNA aptamers that are specific for different targets that are highly expressed on the tumor cell type used and underepresented on other cancer cell types tested.

Remarkably, two of these aptamers bind at high affinity and high specificity to the extracellular domain of two human receptor tyrosine kinases (RTKs), EGFR and Axl respectively. Following binding, both aptamers hamper ligand-dependent receptor dimerization and autophosphorylation. Further, depending on the targeted RTK, the selected aptamers cause inhibition of cell proliferation and selective cell death in vitro and in vivo.

Since an obvious advantage of RNA-based aptamers that bind cell surface receptors is the possibility to be conjugated to a siRNA and used as cargoes for tissue specific internalization, we thus developed a cell SELEX based protocol to enrich for aptamers that following binding to cell surface are rapidly internalized in a receptor-mediated manner.

The whole-cell SELEX strategy holds a great promise in developing specific molecular probes for cancer biomarker discovery and for cancer diagnostic and therapeutic applications.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 626. doi:10.1158/1538-7445.AM2011-626
Abstract 629: MEK inhibition by selumetinib (AZD6244) inhibits progression with a multicentric antiangiogenic effect and enhances the efficacy of cediranib in orthotopic human lung cancer models
Authors: Takahashi Osamu , Komaki Ritsuko , Smith Paul D. , Jürgensmeier Julian M. , Ryan Anderson J. , Bekele Benjamin N. , Wistuba Ignacio I. , Jacoby Jörg J. , Korshunova Maria V. , Biernacka Anna , Erez Baruch , Hosho Keiko , Herbst Roy S. , O'Reilly Michael S.
Published: June 2012

Background: Selumetinib is a potent orally available MEK 1/2 inhibitor now in clinical development. We evaluated the therapeutic efficacy of selumetinib alone or with cediranib (RECENTIN™), an orally available inhibitor of all 3 VEGFR tyrosine kinases, in distinct K-ras mutant orthotopic human non-small cell lung cancer models.

Methods: NCI-H441 or NCI-H460 cells were injected into the lungs of mice. Mice were randomized to treatment with selumetinib (12.5 or 25 mg/kg/BID po), cediranib (3 mg/kg/qd po), paclitaxel (200 µg/week ip), selumetinib + cediranib, or vehicle. When controls became moribund, all mice were sacrificed and assessed and lung tumors subjected to immunohistochemical analyses.

Results: In both models, selumetinib or cediranib were well tolerated and inhibited tumor growth and metastasis with efficacy superior to paclitaxel. The combined antitumor effects of selumetinib and cediranib were markedly enhanced with near complete metastasis suppression. Immunohistochemistry revealed that cediranib or selumetinib reduced microvessel density and tumor cell proliferation and increased apoptosis, with no effect on VEGFR2 expression. The effects were substantially enhanced when they were combined. Cediranib blocked VEGFR2 activation. Selumetinib's antiangiogenic effect, but not cediranib's, was associated with reduced VEGF expression, particularly in the H441 model. Surprisingly, selumetinib reduced tumor and endothelial VEGFR2 activation, which may in part be due to the offset of VEGF expression.

Conclusions: The combination of selumetinib and cediranib enhances their antitumor, antimetastatic, and antiangiogenic effects. Selumetinib decreased VEGF and suppressed VEGFR activation, suggesting that MEK inhibition targets VEGF-driven angiogenesis at multiple levels. These data provide a strong basis for clinical trials of selumetinib and cediranib in lung cancer.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 629. doi:10.1158/1538-7445.AM2011-629