bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 3459: Loss of p16INK4a gene renders mice more susceptible to DMBA-induced mammary carcinogenesis
Authors: Naseemuddin Mohammed , Nasti Tahseen H. , Yusuf Nabiha
Published: February 2011

Breast cancer is the most common type of cancer diagnosed in women. The incidence of breast cancer varies with environmental influences, including carcinogen exposure. Polyaromatic hydrocarbons (PAH), have been implicated as etiologic agents in breast cancer. Exposure occurs primarily through the smoking of tobacco, inhalation of polluted air, and ingestion of charred foods. One such example of a carcinogenic polyaromatic hydrocarbon is 7,12-dimethylbenz(a)anthracene (DMBA) which in animal models, induces mammary adenocarcinoma. p16, a low molecular weight tumor suppressor protein, and a major CDK inhibitor, is the product of a tumor suppressor p16/INK4a gene. It is frequently inactivated in the human tumors. In the present study, we were interested to evaluate the role of p16INK4a in DMBA-induced mammary carcinogenesis. Tumor latency was higher in p16INK4a−/− compared to WT (C3H/HeN) counterparts. Tumors from p16INK4a−/− mice were very aggressive as revealed by PCNA and Ki67 staining and qRT-PCR analysis. The levels of angiogeneic markers CD31 and VEGF were also higher in the tumors of p16INK4a−/− mice as compared to WT mice. These results indicate that restoration of p16INK4a−/− function can be helpful in reducing mammary tumors caused by environmental pollutants like DMBA.

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 3459.
Abstract 3460: Reactive oxygen species generated by cadmium play a role in the upregulation of aldo-keto reductase 1C3 in RPMI 2630 nasal carcinoma cells
Authors: Lee Yoon Jin , Hur Soo-Hark , Nam Hae Seon , Cho Moon Kyun , Lee Sang Han
Published: February 2011

Cadmium (Cd) is a carcinogenic metal which induces oxidative stress through the generation of reactive oxygen species (ROS). Therefore, the ability of cells to up-regulate their antioxidant enzymes is fundamental in the protection of cells and tissues from oxidative damage. In probing the possible survival mechanism of cancer cells to Cd-induced oxidative stress, we examined the ability of Cd to regulate the level of aldo-keto reductase 1C3 (AKR1C3), which has an anti-oxidative role that catalyzes the reductive detoxification of reactive aldehydes and ketones. Exposure of cells to Cd induced a dose- and time-dependent increase in the AKR1C3 expression in the RPMI 2640 nasal septum carcinoma cells, and this up-regulation was blocked by the free radical scavenger N-acetylcysteine (NAC). Additionally, we confirmed that Cd triggered a rapid increase in the intracellular ROS levels, and this increase was inhibited by pretreatment with NAC, which suggests that the up-regulation of AKR1C3 expression involves ROS signaling. Furthermore, pretreatment of cells with LY294002, a pharmacologic inhibitor of phosphatidylinositol-3-kinase (PI3K), suppressed the Cd-augmented AKR1C3 expression; however, inhibition of PKC or MEK1/2 signaling with Go6976 or PD98059, respectively, did not alter Cd-induced AKR1C3 expression. Collectively, these data suggest that Cd can modulate the expression of the AKR1C3 by activation of PI3K via the generation of ROS in RPMI2640 cells, which would contribute to adaptive response to oxidative stress.

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 3460.
Abstract 3466: Increased steady-state levels of microtubules in aberrant distributions in Ni+2 ion-/MCA-transformed C3H/10T1/2 mouse embryo cell lines
Authors: Pehl-De Silva Aruni T. , Samala Preethi , Lee Hongkyu , Landolph Joseph R.
Published: February 2011

We previously found amplification of the Ect-2 proto-oncogene, and higher steady-state levels of ect-2 mRNA and protein, in Ni+2 ion- and MCA-transformed C3H/10T1/2 (10T1/2) mouse embryo fibroblast cell lines. Here, we tested the hypotheses that there were 1) increased steady-state levels of microtubules in Ni+2/MCA-transformed 10T1/2 cell lines, 2) aberrant distributions of microtubules in transformed cell lines, and 3) increases in cross sectional areas of transformed cell lines. Log phase Ni+2 ion- and MCA-transformed and non-transformed 10T1/2 mouse embryo cells were stained separately with fluorescent antibodies to alpha tubulin or beta tubulin, then visualized using confocal microscopy (n=8). The number of microtubules/cell and cross sectional areas of stained cells were quantified using the volocity image analysis program, and ratios of (microtubules in transformed cell lines/microtubules in non-transformed 10T1/2 cells) were determined. In non-transformed 10T1/2 cells, microtubules were distributed homogeneously. In transformed cells, microtubules were often present as large aggregates in cells, and shapes of transformed cells were aberrant compared to shapes of non-transformed 10T1/2 cells. Compared to non-transformed 10T1/2 cells, MCA Cl 16, NiS3A1, NiS7A1 and NiO2C3 cell lines had a 2.1 (p < 0.001), 1.5 (p > 0.05), 1.8 (p > 0.05) and 1.9 (p < 0.05) fold higher fluorescent intensity for alpha tubulin, respectively. Compared to non-transformed 10T1/2 cells, MCA Cl 16, NiS3A1, NiS7A1 and NiO2C3 had 2.5 (p < 0.05) 1.7 (p<0.05), 1.8 (p>0.05) and 1.1 (p<0.05) fold-higher beta tubulin fluorescence intensity relative to 10T1/2 cells. Transformed cell lines showed 1.9 - 2.5 significant (p<0.1) fold-increases in cross-sectional area compared to non-transformed 10T1/2 cells (n = 8). We concluded MCA-/Ni+2 ion-transformed 10T1/2 cells had higher steady-sate levels of microtubules, present in aberrant distributions, and transformed cells were larger than non-transformed cells. Supported by Grant ES03341 from U. S. N. I. H., funding from the M. S. Program in the Dept. of Molecular Microbiology/Immunology at USC, and discretionary funding, to JRL.

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 3466.
Abstract 3467: Repeated particulate chromate exposure induces chromosome instability and a DNA double strand break repair-deficient phenotype in human lung cells
Authors: Wise Sandra S. , Holmes Amie L. , Xie Hong , Pelsue Stephen , Thompson W. Douglas , Wise John P.
Published: February 2011

Particulate hexavalent chromium (Cr(VI)) is a potent respiratory carcinogen with widespread human exposure. The particulate form, for example lead chromate, has been determined to be the most toxic and carcinogenic form. These particles impact at bifurcation sites of the lung and persist in the respiratory tract. Chromosome instability (CIN) is a hallmark of lung cancer with cells exhibiting both translocations and severe aneuploidy. However, the ability of Cr(VI) to induce translocations is unknown. We exposed human lung cells to lead chromate for three sequential 24 h periods, each separated by about a month. After each treatment, cells were seeded at colony forming density, cloned, expanded and retreated. Each generation of clones were tested for their chromium sensitivity, chromosome complement and DNA repair capacity. We found that after the first treatment, lead chromate-treated cells exhibited a normal chromosome complement though a few clones showed an increase in relative survival. After the second exposure, more than half of the clones acquired an abnormal karyotype including numerical and structural alterations. The third treatment resulted in more abnormal clones as well as previously abnormal clones acquiring additional abnormalities. Clones were also treated with soluble Cr(VI) for 24 h followed by a 24 h recovery period to measure DNA double strand break repair. Abnormal clones showed little or no reduction in H2A. X foci formation after 24 h recovery suggesting that these clones had acquired a DNA double strand break repair- deficient phenotype. This work was supported by NIEHS grant ES016893 (J.P.W.).

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 3467.
Abstract 3471: Reciprocal roles of cytochromes P4501A1 and 1A2 in polycyclic aromatic hydrocarbon (PAH)-mediated tumorigenesis in mice: Implications for lung cancer in humans
Authors: Moorthy Bhagavatula , Wang Lihua , Jiang Weiwu
Published: February 2011

Humans are constantly exposed to environmental carcinogenic polycyclic aromatic hydrocarbons (PAHs) through cigarette smoke, diesel exhausts, charcoal-broiled meats, etc. Cytochrome P4501A (CYP1A) enzymes play important roles in the activation of PAHs such as 3-methylcholanthrene (MC) to carcinogenic DNA-binding metabolites. The resulting DNA adducts may lead to mutations of tumor suppressor genes such as p53, thereby leading to tumorigenesis. In this study, we tested the hypothesis that CYP1A1 and 1A2 have reciprocal roles in PAH-mediated tumorigenesis. Eight week-old female wild type (WT) (A/J) mice or mice lacking the gene for CYP1A1 or CYP1A2 on the A/J background were treated with a single dose of MC (40 µmol/kg), benzo[a]pyrene (BP), or vehicle (corn oil), and liver and lung tumors were studied after 28 weeks. While 100% of WT or Cyp1a2-null mice exposed to MC showed lung tumors after 28 weeks, about 80% of the Cyp1a1-null mice showed lung tumors. However, there were striking differences in the Cyp1a1-null and Cyp1a2-null in regard to lung tumor multiplicities and sizes of tumors. The WT mice treated with MC had about 15 lung tumors/animal. On the other hand, the Cyp1a2-null mice displayed about 40 lung tumors/animal, while the Cyp1a1-null mice showed about 2-3 tumors/mouse. Also, the tumor sizes were much larger in the Cyp1a2-null mice, compared to the much smaller sizes in the Cyp1a1-null mice. Although BP was less potent in inducing lung tumors in the WT mice compared to MC, it was similar to MC In that tumors were suppressed in the Cyp1a1-null mice and augmented in the Cyp1a2-null mice. Immunohistochemical studies showed that CYP1A1 was overexpressed in the tumorous portions of the lung in the Cyp1a2-null or WT mice, compared to non-tumorous regions, These results suggest that CYP1A1 contributes to the formation of tumorigenesis by PAHs, while CYP1A2 plays an important role in the protection against carcinogenesis mediated by PAHs, presumably through it role in PAH detoxification. In conclusion, our results strongly suggest that CYP1A1 and 1A2 could be novel candidates for cancer prevention and therapy though either inhibition of CYP1A1 or induction of CYP1A2. Thus, CYP1a1-null and Cyp1a2-null mice could be developed as novel animal models for future cancer prevention and/or therapeutic intervention in humans exposed to environmental PAHs. (Supported by NIH grant ES009132.)

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 3471.
Abstract 3473: Prolonged exposure to zinc chromate induces numerical chromosome instability via centrosome amplification in human lung cells
Authors: Holmes Amie L. , Wise Sandra S. , Pelsue Stephen , Lingle Wilma , Salisbury Jeffery , Gallagher Jamie , Wise John P.
Published: February 2011

Lung cancers are often characterized by numerical chromosome instability. Hexavalent chromium (Cr(VI)) is a well-known human lung carcinogen; however, its carcinogenic mechanism remains unknown. Studies show that solubility plays a key role in its carcinogenicity, with the particulate, or insoluble, compounds being the most potent carcinogens. Epidemiological and whole animal studies pinpoint particulate zinc chromate as the most potent Cr(VI) carcinogen; however, few studies have investigated its carcinogenic mechanism. Therefore, the goal of this study was to determine if zinc chromate induces numerical chromosome instability in human lung cells. We found that exposure to zinc chromate for 24 h did not induce aneuploidy but longer exposures induced both concentration- and time-dependent increases in aneuploid metaphases. For example, exposure to 0.1, 0.15 and 0.2 ug/cm2 zinc chromate for 120 h induced 28, 40 and 44 percent aneuploid metaphases, respectively, with increases in hypodiploid, hyperdiploid and tetraploid metaphases. Consistent with the aneuploidy data, a 24 h exposure to zinc chromate did not induce centrosome amplification but more chronic exposures induced concentration- and time-dependent increases in centrosome amplification in both interphase and mitotic cells. Exposure to 0.1, 0.15 and 0.2 ug/cm2 zinc chromate for 120 h induced centrosome amplification in 13.9, 18 and 21.3 percent of interphase cells and 21, 33 and 46 percent of mitotic cells. In order to determine the mechanism of centrosome amplification, we investigated the number of centrioles in each centrosome and found that cells with amplified centrosomes exhibited centrosomes with normal centriole pairs and centrosomes with centriolar defects indicating multiple mechanisms are involved in zinc chromate-induced centrosome amplification. Lastly, we found that chronic exposure to zinc chromate induced a prolonged G2 arrest. All together, these data indicate that chronic exposure to zinc chromate induces numerical chromosome instability via centrosome amplification in human lung cells. This work was supported by NIEHS grant ES016893 (J.P.W.), cooperative agreement #EP-08-01 through the Maine Space Grant Consortium (J.P.W.), EPA GRO Fellowship MA-91685401 (A.L.H.) and the Maine Center for Toxicology and Environmental Health at the University of Southern Maine.

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 3473.
Abstract 3476: Combined blockade of IGF-I receptor and VEGF for gastric cancer
Authors: Adachi Yasushi , Yamamoto Hiroyuki , Li Hua , Ohashhi Hirokazu , Ii Masanori , Arimura Yoshiaki , Endo Takao , Kato Yasuo , Carbone David P. , Imai Kohzoh , Shinomura Yasuhisa
Published: February 2011

Background Insulin-like growth factor-I receptor (IGF-IR) signaling is required for tumorigenicity and tumor progression of gastrointestinal (GI) cancers. We have shown successful therapy for GI cancers using adenoviruses expressing dominant negative IGF-IR (IGF-IR/dn). On the other hand, IGF-IR signaling affects on vascular endotherial growh factor (VEGF) expression in some tumors. Here, we sought to evaluate the roles of IGF-IR on tumor angiogenesis and lymphangiogenesis and to develop targeting therapy for gastric cancer. Methods The impact of IGF signals on VEGF-A/C expression in gastric cancer cell was assessed. The effects of IGF-IR/dn alone and with bevacizumab on angiogenesis / lymphangiogenesis in mouse xenogfarts were assessed. Results IGFs induced expressions of VEGFs and up-regulated in vitro vascular vessel formation. IGF-IR/dn reduced those expressions and vascular formation. IGF-IR/dn down-regulated tumor size on mice via inhibiting both angiogenesis and lymphangiogenesis. The combination of IGF-IR/dn and bevacizumab was highly effective against tumors on mice. This combination reduced the expression of VEGF and induced apoptosis in the murine tumors most of all. Conclusions IGF-IR is involved in angiogenesis and lymphangiogenesis in gastric cancer. Targeting IGF-IR alone and with blocking VEGF may have therapeutic utility of prevention for gastric cancer progression.

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 3476.
Abstract 3479: SMAC mimetic (JP1201) sensitizes non small cell lung cancers (NSCLCs) to multiple chemotherapy agents and erlotinib in an IAP dependent but TNFα independent manner
Authors: Greer Rachel M. , Peyton Michael , Girard Luc , Xie Yang , Gazdar Adi F. , Harran Patrick , Wang Lai , Brekken Rolf A. , Wang Xiaodong , Minna John D.
Published: February 2011

Tumor cells have acquired resistance to apoptotic stimuli, which is thought to contribute to chemotherapy resistance. Therefore strategies to re-engage apoptotic cascades have strong therapeutic potential. One family of proteins that is key in deregulating apoptosis are the Inhibitors of Apoptosis Proteins (IAPs), which function by binding to and inhibiting caspases, and are in turn inhibited by second mitochondrial activator of caspases (SMAC). One strategy to re-sensitize tumor cells to apoptosis is to create small molecule mimetics of SMAC, such as JP1201 (Joyant Pharmaceuticals). Initial tests of JP1201 in lung cancer identified ∼15% of NSCLCs that were sensitive to low concentrations of JP1201 as a single agent. In all cases sensitive NSCLCs expressed TNFα which was required for single agent drug sensitivity (Peterson et al., 2007). To extend these findings to the large majority of NSCLCs and prepare for clinical trials, we tested 15 NSCLC lines that are resistant to single agent JP1201 (IC50 ≥ 100 µM) in combination with cisplatin, doxorubicin, gemcitabine, erlotinib, paclitaxel, and vinorelbine in a 5 day MTS based microtiter assay. We find great heterogeneity among NSCLCs in tumor cell response phenotypes to combined JP1201 + chemotherapy agents and that for each NSCLC at least one chemotherapy was sensitized by JP1201 100 to 10,000 fold (significant combination indices). Of note we found no NSCLC where cisplatin was sensitized by JP1201. Surprisingly, we also found examples of antagonism when JP1201 is added. Using siRNAs targeted to cIAP1, cIAP2, and XIAP we found that for gemcitabine, XIAP is the key IAP whose inhibition by JP1201 leads to sensitization, while for paclitaxel and vinorelbine, knockdown of any of the three IAPs sensitizes NSCLCs. None of the treatments induce secretion of TNFα or TRAIL (detected by ELISA) in this panel of NSCLCs. NOD/SCID mice bearing NSCLC NCI-H1395 xenografts were randomized (8 mice per group) to 3 weeks of treatment with saline, 25 mg/kg gemcitabine, 2.4 mg/kg vinorelbine, 6 mg/kg JP1201, gemcitabine + JP1201, and vinorelbine + JP1201. Tumor burden was reduced 60% in mice treated with gemcitabine + JP1201 compared to gemcitabine alone, and 70% in mice treated with vinorelbine + JP1201 compared to vinorelbine alone. We conclude that preclinical studies show the combination of JP1201 with chemotherapy is a valid therapeutic strategy for NSCLC.

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 3479.
Abstract 3481: Establishment of preclinical models to identify clinically useful combinations of trifunctional antibodies with chemotherapy
Authors: Dettmar Kirsten , Atz Judith , Lindemann Carsten , Schroeder Petra , Eberhardt Andrea , Kluge Michael
Published: February 2011

The trifunctional bispecific antibodies catumaxomab (anti-EpCAM x anti-CD3) and ertumaxomab (anti-HER-2/neu x anti-CD3) exert their mechanism of action by simultaneous recruitment and activation of two different types of immune effector cells at the tumor site. The interaction of different immune effector cells results in efficient elimination of tumor cells by several killing mechanisms including T-cell cytotoxic responses and direct effects mediated by accessory cells.

Effective treatment of cancer is essentially based on cytotoxic drugs that kill tumor cells or inhibit their proliferation. However, the commonly observed hematotoxicity of chemotherapeutics is regularly associated with some degree of immunosuppression. On the other hand, some of these chemotherapeutic agents are reported to support or even enhance the anti-tumoral effect of immunotherapeutic drugs in certain doses.

A largely intact immune system is the key for trifunctional antibodies to exhibit their full mode of action. Since chemotherapy might impact the number and function of immune effector cells, we evaluated in different preclinical in vitro models whether the efficacy of trifunctional bispecific antibodies would be influenced when combined with chemotherapeutic drugs (5-FU and cisplatin).

The preclinical studies performed included in vitro cytotoxicity assays with established tumor cell lines evaluating potential synergy by using the method of Chou and Talalay. Furthermore, results from 3D tumor spheroids and from an autologous human ex vivo setting are presented.

In addition, immune cells from cancer patients were obtained at different time points during and after chemotherapy and were assessed for their in vitro cytotoxicity mediated by trifunctional antibodies.

So far the results from the different in vitro assay systems used indicate synergy for the combination of the trifunctional antibodies with 5-FU and cisplatin. Furthermore, no negative influence of these chemotherapeutic drugs was observed on the trifunctional mode of action in vitro. These results provide a basis for the possible combination of these drugs with trifunctional antibodies in the clinical setting.

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 3481.
Abstract 3487: Synergy with combined inhibition of upstream EGFR-HER2 and downstream RAF-MEK nodes in breast cancer cells with activating RAS and RAF mutations
Authors: Nagaria Teddy S. , Greer Peter A. , Sangrar Waheed
Published: February 2011

Targeted therapies have been developed to target a variety of oncogenic proteins implicated in breast cancer. These include epidermal growth factor receptor (EGFR), epidermal growth factor receptor type-2 (HER-2), as well as RAS, RAF and MEK, which together comprise the mitogen activated protein kinase (MAPK) cascade. Herein, we explored the therapeutic efficacy of tyrosine kinase inhibitors of EGFR and HER-2 by testing these inhibitors on a human metastatic breast cancer cell line MDA-MB-231. We also determined whether inhibiting tyrosine kinase receptors correlated with the activity of downstream nodes such as MEK and ERK. We report that EGFR inhibitors potently inhibited the phosphorylation of EGFR, but had no effect on MEK and ERK activity, which were observed to be constitutively active in this cell line. Interestingly, MEK/ERK insensitivity correlated with cytotoxic resistance of MDA-MB-231 cells to EGFR inhibitor treatment. In contrast, targeting both EGFR and HER-2 with a dual EGFR/HER-2 inhibitor Lapatinib resulted in significantly improved cytotoxic effects and a partial reduction in MEK and ERK activity. In comparison to the effects of Lapatinib, targeting RAF with Sorafenib resulted in almost complete abrogation of MEK/ERK signaling activity and enhanced cytotoxicity. Our results are consistent with earlier reports suggesting that MAPK signaling is required for MDA-MB-231 cell survival, consistent with the reported presence of activating RAS and RAF mutations in this cell line. Our data highlight the role of RAS and RAF mutations in the uncoupling of downstream nodes (MEK and ERK) from upstream receptor activation. Lastly, the MEK inhibitor U1026 fully inhibited ERK activity but exhibited poor cytotoxicity. This suggests that MDA-MB-231 cells may circumvent MEK inhibition through upstream survival pathways mediated by activated RAS or RAF. An apparent synergistic cytotoxic effect was noted when combining Sorafenib and U1026. Cytotoxic synergy was also observed when Sorafenib was combined with Lapatinib. These putative synergistic drug combinations show promise in that they could deliver significant cytotoxic effects with reduced doses. We find there is merit in targeting multiple oncogenic nodes concurrently to promote additional therapeutic benefits. This also shows potential use in targeting a broader variety of cancer cells that harbor constitutive MAPK signaling associated with oncogenic RAS or RAF mutations.

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 3487.
Abstract 3499: Nanoparticle formulation of SN-38 by the IVECT method results in a safer, more effective treatment for colorectal cancer
Authors: Carie Adam E. , Rios-Doria Jonathan , Cardoen Gregoire , Costich Tara Lee , Sill Kevin
Published: February 2011

Polymeric micelles represent an emerging class of nano-scale vehicles with unmatched potential for delivering potent, targeted chemotherapy. Intezyne's advanced tri-block copolymer system, the IVECT(TM) Method, has been proven to encapsulate a wide variety of therapeutic and diagnostic agents into a proprietary micelle with unique physiochemical properties. Conventional micelles become destabilized rapidly upon dilution into the bloodstream and release a significant portion of their drug payload systemically, harming healthy tissues and limiting therapeutic effects. Intezyne's IVECT Method utilizes a unique cross-linked stabilizer block that maintains micellar structure for a longer period of time post administration and is designed such that a downshift in pH at the tumor activates drug release by destroying the zinc cross-link, allowing for focused drug exposure. The IVECT Method's unmatched plasma stability allows for longer circulation times while protecting healthy tissues, and it maximizes tumor retention and efficacy through the enhanced permeability and retention (EPR) effect and pH-responsive cross-linker. Intezyne's lead product IT-141 encapsulates the extremely potent active metabolite of irinotecan, SN-38. Recently, IT-141 has demonstrated 14-fold greater plasma exposure and 8-fold greater tumor accumulation vs. irinotecan. This superior pharmacokinetic profile confers 500% greater anti-tumor activity at half the dose (30mg/kg, 3X Q4D, vs. 60mg/kg irinotecan). In xenograft models, IT-141 has demonstrated tumor regression of up to 88%, with 60% of tumors regressing completely. The IVECT copolymer is safe and well tolerated at up to 6 times the therapeutic doses, with no sick mouse syndrome, and can be lyophilized for long-term storage (>1 year). Intezyne is preparing its IND for IT-141. The Company has additional programs in development that focus on delivering best-in-class chemotherapies.

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 3499.
Abstract 3509: Design, synthesis and biological evaluation of a novel series of anthrapyrazoles linked with netropsin-like oligopyrrole carboxamides as anticancer agents
Authors: Zhang Rui , Wu Xing , Guziec Lynn , Guziec Frank , Yalowich Jack C. , Chee Gaik-Lean , Hasinoff Brian B.
Published: February 2011

Anticancer drugs that bind to DNA and inhibit DNA-processing enzymes represent an important class of anticancer drugs. Combilexin molecules, which combine DNA minor groove binder and intercalator functionalities, have the potential for increased DNA binding affinity and increased cytotoxicity due to their dual mode of DNA binding. In this study DNA minor groove binder netropsin analogs containing either a mono-N-methylpyrrole carboxamide or two units of N-methylpyrrole carboxamide linked to DNA intercalating anthrapyrazoles were synthesized. Two of the hybrid molecules which possessed bis-methylpyrrole moities and amine head groups displayed submicromolar cytotoxicity towards K562 human leukemia cells. The synthesized hybrids were also evaluated for DNA binding by measuring the increase in DNA melting temperature, for DNA topoisomerase IIα-mediated double strand cleavage of DNA, for inhibition of DNA topoisomerase IIα decatenation activity, and for inhibition DNA topoisomerase I relaxation of DNA. Several of the compounds stabilized the DNA-topoisomerase IIα covalent complex, indicating that they acted as topoisomerase IIα poisons. The results indicate that the hybrid agents have higher affinity for DNA than the parent compounds. In conclusion, a novel group of compounds combining DNA intercalating anthrapyrazoles and minor groove binding netropsin analogs have been designed, synthesized and biologically evaluated as possible novel anticancer agents. Support: CIHR, a Canada Research Chair in Drug Development, National Institutes of Health grant CA090787 to J.C.Y., the Dishman Foundation at Southwestern University and the Robert A. Welsh Foundation.

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 3509.
Abstract 3511: Modulation of HIF-1α by topotecan is related to topoisomerase I-associated with HIF-1α mRNA in ovarian cancer
Authors: Parmakhtiar Basmina , Han Ernest , Fruehauf John P.
Published: February 2011

Topotecan (TPT) is an agent which targets topoisomerase I (Topo I) and is used in the treatment of platinum-resistant and/or recurrent ovarian cancer. We have previously reported that topotecan inhibits hypoxia inducible factor 1α (HIF1α) stabilization, leading to decreased HIF-1α protein and depression of vascular endothelial growth factor (VEGF) levels in ovarian cancer cell lines. Furthermore, we have shown a Topo I: HIF-1α mRNA association using RNA-immunoprecipitation. The aim of this study was to further elucidate the mechanism by which topotecan knocks down HIF-1 alpha and the nature of its dependence on Topoisomerase I. CAOV3 (high Topo I expressing) ovarian cancer cells were used to carry out Topo I knockdown studies using Topo I siRNA in both normoxic and hypoxic (0.5% O2) conditions. Topo I and HIF-1α transcript levels were determined by quantitative PCR and protein expression was evaluated via western blot analysis. Topo I and HIF-1α protein levels were normalized to B-Actin controls. RT-PCR analysis did not show a significant decrease in HIF-1α transcript levels with Topo I siRNA treatment compared to untreated and negative control siRNA treated cells. An 80% decrease in Topo I protein expression was obtained using 30nM Topo I siRNA for both normoxic and hypoxic conditions. An ∼2.30 fold increase in HIF-1α protein expression was seen in Topo I knockdown cells compared to negative control siRNA treated cells after 800nM topotecan treatment under hypoxic conditions. 800nM TPT yielded an 80% decrease in Topo I protein expression with negative control siRNA treated cells under both normoxic and hypoxic conditions. However, 800nM TPT showed complete inhibition of Topo I protein stabilization in Topo I siRNA treated cells. Our results suggest that Topo I is required for Topotecan to inhibit HIF-1α protein stabilization. Furthermore, they also suggest that Topo I may be modulating its own transcript levels. Further studies are being carried out to verify these findings and will be reported at the AACR conference.

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 3511.
Abstract 3512: Novel DNA alkylating agent BO-1090 is a potential candidate for oral cavity cancer therapy
Authors: Sanjiv Kumar , Su Tsann-Long , Lee Te-Chang
Published: February 2011

Human death from oral cancer is the 4th most common in male and over all 6th most common cause of cancer death in Taiwan. Surgery, radiotherapy in combination with chemotherapy is the most common line of treatment for oral cavity cancer. Although cisplain, 5FU, Docetexal, Pinyangmycin etc are the common drugs being used in clinic, there is no any specific drug for oral cavity cancer. In that direction BO-1090 a newly synthesized alkylating agent has potential to be more specific drug for oral cancer based on its potent in vitro cytotoxicty to oral cancer cells, such are OECM-1, SAS, OC3 and CAL-27 in comparison to other cancer cell lines, including lung cancer H1299, prostate cancer cell PC3 and neuronal cell line U87. BO-1090 target DNA for its cytotoxic effects that have been confirmed by alkaline gel shift assay, BrdU based DNA synthesis inhibition assay, Comet assay and γH2x detection. BO-1090 has been tested for its therapeutic potential in SAS cell xenograft mouse. At a dose of 60 mg/Kg i.v five times, it significantly delays the tumor growth in comparison to the control group of mice. Its tumor efficacy in SAS cell xenograft is better than the cisplatin at dose of 4 mg/kg i.v three times. Based on these preliminary results it suggests that B0-1090 can be a useful drug either alone or in combination with other knows drugs in oral cavity cancer therapy. As to the modes of actions of BO-1090, here is activation of CHK-2 check point in response to DNA damage by BO-1090 as well as late activation of p53 and p21. The late activation of P53 may be due to DNA replication blocked by BO1090. During propidium iodide staining based cell cycle analysis, BO-1090 induces G1/ S phase arrest in SAS cell that further confirmed by BrdU incorporation based pulse chase experiment. G1/S phase arrest may be due to combined effects of CDC 25A degradation and activation of p53 and p21 in response to BO-1090 induced DNA damage. G1/S phase arrest in cell by BO-1090 is not a common feature of a DNA alkylating agent, most of DNA alkylating agent induce G2/M phase arrest. In Annexin V based apoptosis assay, our results show that BO-1090 induces apoptosis in SAS and OECM-1 cell by time and dose dependent manner through caspase dependent pathway. By using bioinformatic approach and preliminary experiments suggest that PIM-1 may be also one of its molecular targets.

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 3512.
Abstract 3528: Mutational analysis of threonine 402 adjacent to the GXXXG dimerization motif in TM1 of ABCG2
Authors: Ierano Caterina , Polgar Orsolya , Tamaki Akina , Stanley Bradford , Ward Yvona , Xia Di , Tarasova Nadya , Robey Robert W. , Bates Susan E,
Published: February 2011

ABCG2 is an ATP-binding cassette half-transporter important in normal tissue protection, drug distribution and excretion. ABCG2 requires homodimerization for function, though the mechanism for dimerization has not been worked out. We carried out mutational analysis of threonine 402, three residues away from the GXXXG motif in TM1, to study its potential role in ABCG2 dimerization (TXXXGXXXG). Single mutations to leucine (T402L) or arginine (T402R) did not have significant impact on the ABCG2 protein. On the other hand, combining the T402 mutations with the GXXXG glycine to leucine mutations (T402L/G406L/G410L and T402R/G406L/G410L) resulted in substantially reduced expression, altered glycosylation, degradation by a proteosome independent pathway and partial retention in the endoplasmic reticulum as suggested by immunostaining, Endoglycosidase H sensitivity and MG132 and bafilomycin failed effect. The T402L/G406L/G410L mutant when incubated with the ABCG2-substrate mitoxantrone showed a shift on immunoblot analysis to the band representing the fully matured glycoprotein. The T402R/G406L/G410L mutant carrying the more drastic substitution failed to shift to the surface with mitoxantrone. The same set of mutations also displayed impaired dimerization in the TOXCAT assay for TM1 compared to the wild type. Homology modeling of ABCG2 places the TXXXGXXXG motif at the dimer interface. These studies are consistent with a role for the extended TXXXGXXXG motif in ABCG2 folding, processing, and/or dimerization.

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 3528.
Abstract 3531: Different isoforms of drug-resistant genes may influence breast cancer survival
Authors: Elshimali Yayha , Chen Daniel , Wu Yanyuan , Vadgama Jaydutt V.
Published: February 2011

One major impediment to the success of chemotherapy in cancer patients is the risk of developing drug resistance. One mechanism leading to multidrug resistance in cancer therapy is through the ABC transporters. The eukaryotic ABC genes are organized as transporters containing two transmembrane and two ATP binding domains. Alternative splicing is one major mechanism in which a single gene generates functional diversity by producing different spliced isoforms. To determine the variability of ABC transporters, we performed exhaustive search of the NCBI database for ABC transporter genes, in addition to using the Alternative Splicing Annotation Project (ASAP) and the Alternative Splicing Database (ASD). We conducted immunostaining for MRP1 and MDR1 on tissue micro array of 23 breast cancer patients and RNA mediated annealing, selection, extension and ligation (RASL) assay for analysis of mRNA splicing isoforms which was performed on exon/exon target. Tumor cells from chemotherapy resistant patients show specific expression patterns of drug-resistant ATP-binding cassette transporter. Our data showed alternative splicing in 3 and 4 exon/exon borders in MDR1 and PGP genes. Two splicing events in MDR1 and one in PGP transcripts were predicted to be alternatively spliced in ASAP database. Interestingly, exon11/12 border in MDR1 is found to be alternatively spliced. In summary, protein microarray analysis demonstrated significant correlation between MRP1 expression and survival rate within 5 years. In contrast, MDRI protein expression did not correlate with 5 year survival rate. This may be due to variations in the MDR1 isoforms.

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 3531.
Abstract 3533: Resistance is useless: Development of the MDR1-selective agent NSC73306
Authors: Hall Matthew D. , Handley Misty D. , Pluchino Kristen , Brimacombe Kyle R. , Gottesman Michael M.
Published: February 2011

The thiosemicarbazone NSC73306 is one of several agents identified in a screen for agents that selectively kill cells expressing the multidrug resistance transporter P-glycoprotein (MDR1, ABCB1, P-gp). Prolonged exposure of P-gp expressing cells to NSC73306 down-regulates P-gp, re-sensitizing the cells to conventional chemotherapeutics. Given the exciting potential for NSC73306 as a potential therapy for previously intractable multidrug resistant cancer cells, in vitro and in vivo validation is underway. A series of NSC73306 analogs have been synthesized in order to examine the structural requirements for MDR1-selectivity of this family of compounds, and a proposed pharmacophore for MDR1-selectivity has been generated. In parallel, new MDR1-selective chemotypes are being discovered and validated through a number of strategies, including bioinformatic, high throughput screening and drug design approaches.

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 3533.
Abstract 3536: The biphasic mechanism of TNF-alpha mediated modulation of mdr1 expression and chemosensitization of colon cancer cells is linked to the NFkappaB pathway
Authors: Walther Wolfgang , Bauer Lisa , Aumann Jutta , Stein Ulrike
Published: February 2011

Multidrug resistance (MDR) is one major cause for cancer chemotherapy failure. Therefore, numerous overcoming strategies have been tested for tumor chemosensitization. Among these, persistent action of proinflammatory cytokines, such as tumor necrosis factor-alpha (TNF) showed great potential for downregulation of MDR-associated genes, particularly for the ABC-transporter P-glycoprotein Pgp, encoded by the mdr1 gene. These cytokine-mediated effects are still under controversial discussion, since transient action of TNF was shown to increase mdr1 expression, whereas persistent TNF action reduces mdr1 expression. Key mediator for this is the transcription factor NFkappaB/p65. This factor is acting via binding to NFkappaB/p65 consensus sequences within the mdr1 promoter. To determine the cellular mechanisms of TNF mediated modulation of mdr1 expression, we analyzed transient and persistent effects in regard to biphasic NFkappaB signaling in colon carcinoma cells.

The mdr1 overexpressing, multidrug resistant human HCT15 colon carcinoma cells were treated for transient 30 to 120 min or long-term, 24 to 96 h incubations with TNF. The TNF mediated modulation of mdr1 expression was analyzed by real-time RT-PCR and Western-blot. Involvement of TNF-receptor I or II and time-dependent analysis of NFkappaB/p65 signaling was determined by Western blot, luciferase cell signaling reporter assay and EMSA.

Our studies revealed that the persistent long-term action of TNF leads to down-regulation of mdr1 at mRNA and protein level. We showed, that this effect is mediated by TNF-receptor I, which is known to trigger the NFkappaB/p65 pathway. More importantly, the persistent TNF action on the colon cancer cells abolishes TNF mediated induction of the NFkappaB/p65 signaling, associated with reduced nuclear accumulation of NFkappaB/p65 and also its impaired binding to the consensus sequence of the mdr1 promoter. This study supports the biphasic nature of TNF action and points to the contrary effects of transient or persistent action of this cytokine. It provides insights into mechanism of MDR overcoming in colon cancer and potential clues for effects associated with chronic inflammation of the intestine

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 3536.
Abstract 3543: Activation of the ERK pathways overcome the cisplatin-resistance in ovarian carcinoma cells
Authors: Nonaka Michiko , Itamochi Hiroaki , Kawaguchi Wakae , Uegaki Kazunori , Naniwa Jun , Sato Shinya , Shimada Muneaki , Oishi Tetsuro , Terakawa Naoki , Kigawa Junzo , Harada Tasuku
Published: February 2011

Objective: Cisplatin (CDDP) is a key drug used to treat ovarian carcinoma that activates the mitogen-activated protein kinase kinase (MEK)-extracellular signal-regulated kinase (ERK) signaling cascade and a phosphatidylinositol 3′-kinase (PI3K)-Akt pathway, both of which are considered pathways for cell proliferation and survival. The present study aimed to elucidate the roles of the MEK-ERK and PI3K-Akt pathways in regulating cytotoxicity in ovarian carcinoma cells induced by CDDP.

Methods: Seven human ovarian serous adenocarcinoma cell lines were used in this study (KF, KFr, KOC-2S, SK-OV-3, SHIN-3, TU-OS-3, and TU-OS-4). We treated the cell lines with CDDP combined with PI3K inhibitor (LY294002 [LY]), MEK inhibitor (PD98059 [PD]), or ERK activator (phorbol 12-myristate 13-acetate [PMA]), then assessed cell viability by a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The levels at which proteins expressed MEK, phosphorylated (p)MEK, ERK, pERK, Akt, pAkt, and cleaved caspase-9 were detected by western blotting. Cell cycle distribution and apoptotic cells were determined by flow cytometry, 5-bromo-2-deoxyuridine (BrdU) incorporation, and staining with Annexin V.

Results: The range of IC50 to CDDP was 2.4 to 26.9 μM for those cell lines. KFr, a CDDP-resistant cell line, was established from KF cells, and the IC50 to CDDP was 9.6 μM. We defined the cell lines which had 9.6 μM or higher IC50 value as CDDP-resistance. Proteins MEK, pMEK, Akt, pAkt, ERK and pERK were expressed in all cell lines. CDDP combined with LY had an additive effect on inhibiting growth of cells in all lines. In contrast, we observed an antagonism for all cell lines when CDDP was combined with PD. Interestingly, growth of cells was dramatically suppressed when CDDP was combined with PMA in the CDDP-resistant cells (KFr, SK-OV-3, SHIN-3, TU-OS-3, TU-OS-4). Treatment with PMA upregulated protein expression levels of pERK and cleaved caspase-9 only in the CDDP-resistant cells. CDDP combined with PMA increased the S-phase fraction and apoptotic cells in the CDDP-resistant cells. Conclusion: ERK activated by PMA may overcome resistance to CDDP in ovarian carcinoma cells.

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 3543.
Abstract 3551: Role of proteasome in the development of multidrug resistance in childhood rhabdomyosarcoma
Authors: Armeanu Sorin , Laizer Natalie , Brücher Björn , Fuchs Jörg , Seitz Guido
Published: February 2011

Multidrug resistance (MDR) is a common problem in the treatment of childhood rhabdomyosarcoma (RMS). The aim of this study was to investigate different mechanism of MDR in childhood RMS and to analyze possible reversal strategies.

Female athymic mice underwent xenotransplantation with embryonal (A204) or alveolar (Rh30) RMS cells and were treated with vincristine (0.75 mg/kg/d i.p.). Gene expression analysis with Affymetrix oligonucleotide microarrays HU-Gene 1.0 revealed 2314 differentially expressed genes between the groups in alveolar RMS and 1387 in embryonal RMS. Ingenuity Pathways Analysis of biological pathways and functions of these genes revealed a cluster 21 genes related to the ubiquitin pathway. Among them 4 genes shown an up-regulation and 17 a 0.5 lower expression in vincristine treated samples. Furthermore, among of 45 genes of the proteasome cluster with 35 being down-regulated in RMS from animals treated with vincristine, putative mediating the development of MDR. Changes of gene expression were confirmed by qRT-PCR for selected proteasome components, such as PSMB1, PSMB6 and PSMD14. Specific inhibition of proteasome activity with bortezomib and MG132 inhibits proliferation of RMS cells, but reduces the cytotoxic activity of vincristine in a cell vitality assay. Our results emphasize the role of proteasome in the development of MDR in rhabdomyosarcoma treated with vincristine.

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 3551.