bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 473: CD4+ T cell help differentially influences anti-tumor immunity as a function of T cell avidity
Authors: Zhu Ziqiang , Singh Vinod , Bronte Vincenzo , Feigenbaum Lionel , Hurwitz Arthur
Published: June 2012

One of the major hurdles for cancer immunotherapy is that most tumors express self-antigens to which the immune system is unresponsive due to self-tolerance. Our lab and others have demonstrated that high-avidity tumor-specific CD8+ T cells are superior in anti-tumor activity to low avidity T cells. However, adoptive transfer of high-avidity, tumor-specific CTL populations may fail due to loss of CTL effector functions upon tumor infiltration. Therefore, strategies to maintain effector functions of high avidity CTL, or enhancement of low avidity CTL are desirable. To investigate whether provision of CD4+ T cell help will enhance the effectiveness of high-avidity CTLs in anti-tumor immunity as compared to lower avidity T cells, we utilized two transgenic mouse lines developed in our lab that bear different TCR transgenes specific for a common melanoma differentiation antigen, tyrosinase-related protein 2 (TRP-2(180-188)). T cells from clone 24 TCR Tg mice (TCRhi) show higher avidity than those from clone 37 (TCRlo) mice based on tetramer dissociation and in vitro effector function assays. Here we report that co-activation of CD4+ T cells (OVA323-339 specific, CD4-OVA) with TRP-2-specific CD8+ T cells can boost the in vitro function of TCRhi cells, including proliferation, IFN-γ secretion, Gr-B secretion as well as cell-mediated cytotoxicity, but had minimal effect on TCRlo cells. We observed that only adoptive co-transfer of CD4-OVA cells with TCRhi cells suppressed tumor growth of (5 day) established B16 melanoma tumors. Furthermore, those mice receiving co-transferred CD4-OVA cells with TCRhi cells developed autoimmune depigmentation at the sites of vaccination and tumor challenge. Our finding may have important implications for enhancement of cancer immunotherapy.

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 473. doi:10.1158/1538-7445.AM2011-473
Abstract 4739: Mesenchymal stem cells induce broad spectrum resistance to chemotherapy through the release of platinum-induced fatty acids
Authors: Roodhart Jeanine M.L , Daenen Laura G. , Stigter Edwin C. , Ishihara Kenji , Medema Rene H. , Brenkman Arjan B. , Voest Emile E.
Published: June 2012

Background The development of resistance to chemotherapy is a major obstacle for lasting effective treatment of cancer. It is becoming increasingly clear that the tumor micro-environment plays a key role in the development of drug resistance. Mesenchymal stem cells (MSCs), key players in tissue repair and wound healing, are recruited in large numbers to the stroma of developing tumors where they are known to support tumor growth and enhance metastasis formation.

Aim To determine whether MSCs confer resistance to chemotherapy, we established different murine tumor models in which we resembled the mobilization and recruitment of MSCs from the bone marrow to tumor.

Results Administration of 50,000 MSCs intravenously (iv), or as little as 1,000 MSCs subcutaneously (sc) together with chemotherapy almost completely abolished the anti-tumor effect of the chemotherapy in a dose-dependent matter. Notably, this was only observed with the platinum-based chemotherapeutics, namely cisplatin, oxaliplatin and carboplatin. To show that the MSCs induce resistance in a paracrine fashion, we incubated cultured MSCs with platinum-based chemotherapy and injected the conditioned medium (CM+) from these cells sc concomitantly with the chemotherapy. Strikingly, the CM+ induced an almost complete resistance to multiple types of chemotherapy, including non-platinum based chemotherapeutics like 5-FU and irinotecan. The CM from untreated MSCs (CM-), did not induce resistance. Through a metabolomics approach, we identified two unique platinum-induced polyunsaturated fatty acids (PIFAs), 12-oxo-5,8,10-heptadecatrienoic acid (KHT(n-6)) and hexadeca-4,7,10,13-tetraenoic acid (16:4(n-3)) in the CM+ responsible for the induction of resistance by the MSCs. We tested the purified PIFAs in our mouse models and confirmed that in minute quantities (2pmol) these PIFAs induce resistance to a broad spectrum of chemotherapy. In contrast, other related poly-unsaturated fatty acids had no effect.

Conclusion In summary, our study identifies a novel paracrine mechanism of resistance via activation of MSCs by platinum-based chemotherapy with the subsequent release of two specific resistance-inducing PIFAs. Our findings suggest that interventions directed against either MSC or the identified PIFAs may be explored to enhance the efficacy of chemotherapy and prevent the development of resistance.

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 4739. doi:10.1158/1538-7445.AM2011-4739
Abstract 4749: Aligned collagen is a prognostic signature for survival in human breast carcinoma
Authors: Conklin Matthew W. , Eickoff Jens C. , Riching Kristin M. , Pehlke Carolyn A. , Eliceiri Kevin W. , Provenzano Paolo P. , Andreas Friedl , Keely Patricia J.
Published: June 2012

Evidence for the potent influence of stromal organization and function on invasion and metastasis of breast tumors is ever growing. Here we have performed a rigorous examination of the relationship of a tumor-associated collagen signature (TACS-3), to the long term survival rate of human patients. TACS-3 is characterized by bundles of straightened and aligned collagen fibers that are oriented perpendicular to the tumor boundary. An evaluation of TACS-3 was performed in biopsied tissue sections from 196 patients by second harmonic generation (SHG) imaging of the backscattered signal generated by collagen. Univariate analysis of a Cox proportional hazard model demonstrated that the presence of TACS-3 was associated with poor disease-specific and disease free survival, resulting in hazard ratios between 3.0-3.9. Furthermore, TACS-3 was confirmed to be an independent prognostic indicator regardless of tumor grade and size, ER or PR status, HER-2 status, node status, and tumor subtype. Interestingly, TACS-3 was positively correlated to expression of stromal syndecan-1, a receptor for several extracellular matrix proteins including collagens. Because of the strong statistical evidence for poor survival in patients with TACS, and since the assessment can be performed in routine histopathologic samples imaged via SHG or using picrosirius, we propose that quantifying collagen alignment is a viable, novel paradigm for the prediction of human breast cancer survival.

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 4749. doi:10.1158/1538-7445.AM2011-4749
Abstract 475: Delineation of a cellular hierarchy in lung cancer reveals an oncofetal antigen expressed on tumor-initiating cells
Authors: Damelin Marc I. , Geles Kenneth G. , Follettie Maximillian T. , Yuan Ping , Baxter Michelle , Golas Jonathon , Huang Shuguang , DiJoseph John , Diesl Veronica , Behrens Carmen , Choe Sung E. , Rios Carol , Gruzas Janet , Sridharan Latha , Dougher Maureen , Kunz Arthur , Hamann Philip R. , Evans Deborah , Armellino Douglas , Khandke Kiran , Marquette Kimberly , Tchistiakova Lioudmila , Boghaert Erwin , Abraham Robert T. , Wistuba Ignacio I. , Zhou Bin-Bing S.
Published: June 2012

Poorly differentiated tumors in non-small cell lung cancer (NSCLC) are refractory to chemotherapy and associated with short survival time. Here we integrate multiple experimental models with clinicopathological analysis of patient tumors to delineate a cellular hierarchy in NSCLC. We demonstrate that the oncofetal protein 5T4 is expressed on tumor-initiating cells and associated with worse clinical outcome in NSCLC. Coexpression of 5T4 and factors involved in the epithelial-to-mesenchymal transition was observed in undifferentiated but not in differentiated tumor cells. Despite heterogeneous expression of 5T4 in NSCLC patient-derived xenografts, treatment with an anti-5T4 antibody-drug conjugate resulted in complete and sustained tumor regression. Thus, the aggressive growth of heterogeneous solid tumors can be blocked by therapeutic agents that target a subpopulation of cells near the top of the cellular hierarchy.

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 475. doi:10.1158/1538-7445.AM2011-475
Abstract 4761: Regulation of TNFα-induced cell death of primary human brain microvessel endothelial cells by integrins
Authors: Rani M R Sandhya , Huang Ping , Prayson Richard , Hedayat Hirad , Sloan Andrew E. , Nowacki Amy , Weil Robert , Ahluwalia Manmeet S. , Tipps Russell , Gladson Candece L.
Published: June 2012

TNFα induces cell death of primary human brain microvessel endothelial cells (MvEC) in a dose-dependent manner through TNF-R1 activation. To determine whether TNF-R1 was available to be therapeutically manipulated on tumor-associated endothelial cells in glioblastoma tumors, we evaluated its expression on the endothelial cells in 50 human glioblastoma and 38 normal brain samples by immunohistochemistry. A significantly increased expression of TNF-R1 and TNFα was detected on the endothelial cells in the tumor biopsies as compared to the normal brain samples. We then investigated whether integrins regulate TNF-R1 pro-apoptotic signaling in MvEC isolated from normal brain; these cells proliferate in culture and resemble reactive endothelial cells. TNFα stimulation readily induced cell death of the brain MvEC when plated on collagen or fibronectin (attachment mediated by integrins α2β1 and α5β1, respectively), but the cells were protected from this pro-death signal when plated on laminin (mediated by integrin α6β1). In the cells plated on collagen (not on laminin) a time-dependent increase in the phosphorylation of p38 MAP kinase was detected with TNFα stimulation and knockdown of p38 MAP kinase blocked the TNFα-induced cell death suggesting p38 MAP kinase is a downstream effector for TNFα-induced apoptosis. We then examined whether engagement of a particular integrin signaled for expression of an anti-apoptotic protein and found expression of cFLIP when the MvEC were plated on laminin, but not when the cells were plated on collagen. Furthermore, down-regulation of cFLIP using siRNA restored the pro-apoptotic signal of TNFα in MvEC plated on laminin. To substantiate the clinical relevance of these findings, we examined the effect of TNFα stimulation on endothelial cells isolated from two different glioblastoma tumors, and found that TNFα induced cell death was similarly regulated by the ECM or integrins. Our data suggest that TNF-R1 on tumor-associated endothelial cells in glioblastoma tumors is available to be therapeutically manipulated as part of an anti-angiogenic therapy, and that the effectiveness of such a therapy maybe in part dependent on the activity of specific integrins expressed on the tumor endothelial cells.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 4761. doi:10.1158/1538-7445.AM2011-4761
Abstract 4764: The LTbR mediates immune cell-exerted anti-tumor cytotoxicity
Authors: Hu Xiaolin , Liu Kebin
Published: June 2012

Lymphotoxin beta Receptor (LTβR) belongs to the Tumor Necrosis factor (TNF) receptor superfamily and was originally identified to be critical for the development and maintenance of secondary lymphoid architectures. However, it is increasingly appreciated that the LTβR signaling pathway is involved in induction of extrinsic apoptotic cell death in tumor cells. Strikingly, it was recently observed that sustained expression of LTβR ligands also promote tumor development via a NF-κB-dependent mechanism. Thus, LTβR could function as two-edged sword. There are two physiological ligands, LTα1LTβ2 and LIGHT, that engage the LTβR to initiate signaling transduction. These two ligands are known to be expressed in immune cells. However, whether immune cells use these two ligands to suppress tumor development is unknown. In this study, we observed that LTβR protein in expressed in all tumor cell lines examined and in human colon carcinoma and sarcoma specimens. Engagement of the LTβR with LTβR-specific agonist mAbs activated both the canonical and alternative NF-κB signaling pathways in tumor cells. However, these agonist mAbs at the same time also effectively suppressed the growth of colon carcinoma, melanoma, mammary carcinoma and sarcoma cells in vitro, suggesting that the LTβR-mediated apoptosis signaling pathway overpowers the LTβR-initiated NF-κB signaling pathways to yield an overall tumor suppressive effect. Furthermore, both LTα1LTβ2 and LIGHT were activated in tumor-infiltrating macrophage, NK and T cells. Chimera mice with LTα-, LIGHT- or both LTβ and LIGHT-deficient immune cells exhibited significantly high incidence of MCA-induced tumor and greater tumor growth than chimera mice with wt immune cells. Furthermore, double-deficiency of LTβ and LIGHT in the immune cells resulted in significantly higher tumor incidence and greater tumor growth than LTα-deficiency alone. Taken together, our data suggest that LTβR mediates an immune cell-exerted anti-tumor effector mechanism in vivo.

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 4764. doi:10.1158/1538-7445.AM2011-4764
Abstract 4767: C6 ceramide sensitizes multiple aggressive pancreatic cancer cell lines to gemcitabine, paclitaxel and cetuximab mediated anti tumor effects in vivo and in vitro
Authors: Wanebo Harold J. , Lu Shan , Cong Cao , Shrayer David , Wan Yinsheng , Bowen Wayne
Published: June 2012

Introduction: Pancreatic adenocarcinoma continues to be a highly lethal malignancy (5 yr survival 5%) poorly responsive to all chemo radiation therapies, with only modest improvement with Gemcitabine the current “main line” drug. We have previously demonstrated the C6 Ceramide chemo enhancement of Gemcitabine and other pancreatic chemo agents. The current study explores the mechanism of C6 Ceramide effects on pancreatic chemo resistance pathways – pro-survival and ras-signaling in pancreatic cancer cells. Methods: In vivo: 2-3 month SCID male mice with pancreatic (pan) tumor implants (2 × 106 L3.6 cells) received intraperitoneal (I.P.) injections (3x/wk) of Paclitaxel (Pax) (3.0mg/gm), Gemcitabine (Gem, 10mg/gm) with/without C6 ceramide (10mg/ml) and were observed 6 weeks and tumor response/survival recorded. In vitro: Drug dose Pax 3 ug/ml, Gem 3 ug/ml, C6 Ceramide 10 ug/ml. The MTT anti tumor response was measured in 3 pancreatic lines L3.6, PANC-1, and MIA (Kras mutated). Signaling activation by Western blot utilized antibodies: LY294002, and Wortmannin to block PI3K/AKT pathway, U0126 and PD 98059 to block ERK pathway and Rapamycin to block mTORC1 pathway. Results: Combined therapy with C6 Ceramide induced significant inhibition of exponential tumor growth and prolonged survival by Gem and Pax. Administration of Gem or Pax with C6 Ceramide induced a significant increase in cell death and apoptosis in pancreatic cancer cells (L3.6, PANC-1 and MIA PaCa-2) which were associated with inhibiting perturbations of cell signaling pathways including pro-survival PI3K/Akt/mTOR, and ERK/MAPK, Ras signaling pathways. Pharmacological inhibition with specific signaling pathway inhibitors enhanced cytotoxicity by Gem or Pax, suggesting that survival pathway inhibition might be the key mechanism contributing to C6 Ceramide synergism of Pax or Gem anti-tumor effects. We also showed C6 ceramide potentiation of Cetuximab anti tumor effects on Kras mutant MIA cells thus overcoming (EGFR mAb) resistance by inhibiting pro-survival PI3K/AKT/mTOR pathways and bypassing K-RAS mutant Ras-ERK pathways. Conclusion: C6 Ceramide an apoptosis signal potentiates the anti tumor effects of chemo agents Gemcitabine and Paclitaxel and the biologic EGFR Inhibitor Cetuximab against 3 aggressive pancreatic cancer cell lines by apparent inhibition of the pro-survival PI3K/AKT/mTOR pathways and the Kras mutated ERK/MAPK pathway.

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 4767. doi:10.1158/1538-7445.AM2011-4767
Abstract 4770: TNFα and IFN-γ cooperate to up-regulate Fas expression to sensitize human colon carcinoma cells to Fas mediated apoptosis
Authors: Bardhan Kankana , Liu Kebin
Published: June 2012

Fas (also known as CD95) is a member of the tumor necrosis factor (TNF) superfamily that mediates the extrinsic apoptosis signaling pathway when engaged by its physiological ligand FasL. Although the Fas death receptor has been shown to initiate cellular proliferation and survival signal pathways in certain tumor cells uder certain conditions, it is generally believed that under physiological conditions Fas functions as a guardian against not only autoimmunity but also other disease including cancer. Fas is highly expressed in normal human colon epithelial cells but is often down-regulated in human colorectal carcinoma, whereas complete loss of Fas expression is often observed in metastatic human colorectal carcinoma. These observations thus suggest that colon carcinoma cells might use loss of Fas expression and/or function to acquire an apoptosis resistant phenotype to advance the disease. Therefore, re-activating Fas expression might be an effective approach to sensitize the human colon carcinoma cells to apoptosis to suppress tumor development. In this study, we demonstrated that there exist CpG islands in the human Fas promoter region and inhibition of DNA methylation up-regulates Fas expression in metastatic human colon carcinoma cells, resulting in increased tumor cell sensitivity to Fas-mediated apoptosis. However, bisulfite DNA sequencing revealed that there are just a few methylated CpGs in the human Fas promoter region in metastatic human colon carcinoma cells, suggesting that DNA methylation mediates Fas expression indirectly. On the other hand, TNFα and IFN-γ, when used in combination, dramatically up-regulated Fas expression level in the metastatic human colon carcinoma cells. Up-regulation of Fas by TNFα and IFN-γ also resulted in sensitization of the metastatic colon carcinoma cells to Fas-mediated apoptosis. Our data thus suggest that re-activation of the death receptor Fas might be an effective approach to enhance the efficacy of Fas-based therapy against metastatic human colon 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 4770. doi:10.1158/1538-7445.AM2011-4770
Abstract 4781: XIAP expression is associated with poor prognosis and is a promising therapeutic target for the treatment of papillary thyroid carcinoma
Authors: Hussain Azhar R. , Bavi Prashant , Bu Rong , Ahmed Maqbool , Al-Nuaim Abdulrehman , Ahmed Mohammed , Al-Sobhi Saif , Amin Tarek , Uddin Shahab , Al-Kuraya Khawla S.
Published: June 2012

The inhibitor of apoptosis protein (IAP) family member, X-linked Inhibitor of Apoptosis Protein (XIAP) is essential for cell survival in variety of cancers. However, the role of XIAP overexpression in papillary thyroid carcinoma (PTC) is not fully elucidated. Therefore, we analyzed the expression of XIAP protein and its clinico-pathological correlation in a large cohort of Middle Eastern PTC by immuno-histochemistry in a tissue micro-array format followed by in vitro studies using PTC cell lines. XIAP was found to be over-expressed in 25% of PTC and directly associated with older age (p<0.0001) and presence of extra-thyroidal extension (p<0.0001). Interestingly, XIAP was also found to be significantly associated with tall-cell variant (p=0.0013), larger tumor size (p=0.0002) and advanced stage (III and IV) disease (p< 0.0001). XIAP over-expression was also significantly associated with over-expression of oncogenic c-Met (p=0.0010) and anti-apoptotic Bcl-Xl protein (p<0.0001). Finally, PTC with XIAP over-expression showed a significantly poor disease free survival (p=0.0476) of 63.1 months as compared to the PTC's with low XIAP expression (74.0 months). Our in vitro data showed that embelin, a selective inhibitor of XIAP, caused a dose dependent inhibition of cell proliferation in PTC cell lines. Furthermore, we found that embelin induced a dose dependent apoptosis as detected by cell cycle analysis and annexin V/PI dual staining in PTC cells. On further analysis, our data showed that embelin induced a caspase-dependent apoptosis of PTC cells via activation and cleavage of capsases-9 and -3 and cleavage of PARP. In summary, our clinical data highlights the fact that XIAP over-expression in PTC confer a aggressive phenotype with poor outcome. In vitro studies using XIAP inhibitor suggest that this sub-group of PTC with over-expression of XIAP can be therapeutically targeted to induce efficient apoptosis in these cancers.

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 4781. doi:10.1158/1538-7445.AM2011-4781
Abstract 4782: The NEDD8-activating enzyme inhibitor, MLN4924, cooperates with TRAIL to augment apoptosis through JNK-dependent downregulation of c-FLIP in head and neck cancer cells
Authors: Zhao Liqun , Yue Ping , Lonial Sagar , Khuri Fadlo R. , Sun Shi-Yong
Published: June 2012

The death ligand, tumor necrosis factor-related apoptosis-inducing ligand (TRAIL), is a tumor-selective cytokines with potential anticancer activity and is currently being tested in clinical trials. Like other types of cancers, head and neck squamous cell carcinoma (HNSCC) cells posses varied sensitivity to TRAIL. MLN4924 is a newly developed small molecule inhibitor of NEDD8-activating enzyme with potent anticancer activity. Elevated NEDD8 conjugation has been reported in HNSCC cells. However, the effects of MLN4924 on the growth of HNSCC cells and on TRAIL-induced apoptosis in HNSCC cells have not been evaluated. In this study, we showed that MLN4924 effectively inhibited the growth of HNSCC cells (IC50s < 0.4 μM) with potent apoptosis-inducing activity. Moreover, MLN4924 synergized with TRAIL to decrease the survival and to induce apoptosis of HNSCC cells. Interestingly, MLN4924 decreased c-FLIP levels with minimal effects on DR4 and DR5 expression. Enforced expression of c-FLIP substantially attenuated MLN4924/TRAIL-induced apoptosis. These data indicate that c-FLIP reduction plays an important role in mediating cooperative induction of apoptosis by the MLN4924 and TRAIL combination. Furthermore we found that MLN4924 decreased c-FLIP stability, increased c-FLIP ubiqutination and facilitated c-FLIP degradation, suggesting that MLN4924 decreases c-FLIP levels through promoting its degradation via an ubiqutination and proteasome-dependent mechanism. Additionally, MLN4924 potently activated JNK signaling evidenced by increased levels of phospho-c-Jun in MLN4924-treated cells. Blockage of the JNK activation with the JNK inhibitor SP600125 not only prevented MLN4924-induced c-FLIP reduction, but also inhibited MLN4924/TRAIL-induced apoptosis. These results suggest that JNK activation mediates c-FLIP downregulation and subsequent enhancement of TRAIL-induced apoptosis induced by MLN4924. Our findings thus warrant further evaluation of the efficacy of MLN4924 or its combination with TRAIL against the HNSCC in vivo and highlight a novel mechanism by which MLN4924 modulates apoptosis. (This study was supported by the Georgia Cancer Coalition Distinguished Cancer Scholar award, Department of Defense VITAL W81XWH-04-1-0142 and NIH/NCI Head and Neck Cancer SPORE CA128613 awards. FR Khuri and SY Sun are Georgia Cancer Coalition Distinguished Cancer Scholars)

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 4782. doi:10.1158/1538-7445.AM2011-4782
Abstract 4784: Targeting NF-kappaB pathway with Bay11-7085 leads to inhibition of cell viability and induces apoptosis in primary effusion lymphoma cells
Authors: Hussain Azhar R. , Ahmed Maqbool , Ahmed Saeeda O. , Bu Rong , Khan Omar S. , Platanias Leonidas , Al-Kuraya Khawla S. , Uddin Shahab
Published: June 2012

Primary effusion lymphoma (PEL) is a subtype of non-Hodgkin's B cell lymphoma that mainly grows as a lymphomatous effusion in body cavities and is infected with Kaposi sarcoma-associated herpesvirus (KSVH/HHV8). A number of constitutively activated signaling pathways play critical role in the survival and growth of PEL cells including NF-kB. NF-κB is constitutively activated in a number of cancers including multiple myeloma, burkitt's lymphoma and diffuse large B-cell lymphoma. However, its role in primary effusion lymphoma has not been fully explored. Therefore, in this study, we found that Bay11-7085, an inhibitor of NF-kB pathway inhibit cell viability and induce apoptosis in several PEL cell lines in a dose dependent manner. Such effects of Bay11-7085 result from its ability to in-activate p-IκBα leading to the inability of p65 subunit of NF-κB to enter the nucleus to assert its anti-apoptotic transcriptional activity. Our data demonstrate that Bay11-7085 treatment of PEL cell lines causes de-phosphorylation of Bad protein leading to conformational changes of Bax protein and subsequently translocation from cytosole to mitochondria causing loss of mitochondrial membrane potential with subsequent release of cytochrome c from the mitochondria. Released cytochrome c into the cytosole activates caspases-9 and -3, followed by polyadenosin-5’-diphosphate-ribose polymerase (PARP) cleavage. In addition, pretreatment of PEL cells with zVAD-fmk, a universal inhibitor of caspases prevents caspase-3 activation and abrogates cell death induced by Bay11-7085 treatment of PEL cells strongly suggesting that Bay11-7085-induced apoptosis is caspase dependent. Finally, treatment of PEL cells with Bay11-7085 down-regulates the expression of inhibitor of apoptosis proteins (IAP). Altogether, these data suggest that NF-κB plays an important role in PEL cell survival and targeting this pathway with Bay11-7085 induces caspase dependent apoptosis via disruption of mitochondrial pathway. This raises the possibility that this agent may have a future therapeutic role in PEL and possibly other malignancies with constitutive activation of the NF-κB pathway.

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 4784. doi:10.1158/1538-7445.AM2011-4784
Abstract 4785: Silver nanoparticles induce apoptosis in squamous lung cancer cell by regulation of cyclic AMP response element-binding protein: regulating its upstream oxidative stress-dependent Ras signaling pathways
Authors: Park Hee Sun , Jang Sunhyae , Cha Hye Rim , Jeong Sun Young , Lee Jeong Eun , Kim Ju Ock , Koo Ja Seok , Kim Sun Young
Published: June 2012

Recently, much effort has been devoted to the development of biomedical applications (drug delivery system and as therapeutic drugs themselves) for nanoparticles (NPs). Silver NPs have been shown various therapeutic effects such as antimicrobial, antioxidant, and anti-inflammatory effects. Recently silver NPs have been shown to induce cytotoxicity in cancer cells. But exact mechanism is not yet established. We conducted this study to determine the mechanisms of silver NPs on cellular apoptosis in non-small cell lung cancer (NSCLC) cell lines using cyclic AMP response element-binding protein (CREB) activity which has been implicated to contribute an important pathobiologic role in lung carcinogenesis and is considered a potential therapeutic target for NSCLC. We hypothesized that constitutively increased CREB and its related signaling pathways can be blocked by silver NPs and it might be by regulation of oxidative stress in tumorigenesis. In H520 cell, human lung squamous cancer cell line, reactive oxygen species (ROS) were increased. In western blot analysis, Ras signaling molecule in which ROS is involved was constitutively overexpressed and the levels of pErk, pRsk, pAkt and pCREB were increased in H520 cell. Incubation of the H520 cells with silver NPs (at dose of 100 or 200 μM) substantially suppressed the ROS in H520 cell and Ras-Erk-Rsk-CREB and Ras-PI3K-Akt signaling pathway in a dose-dependent manner. We subsequently demonstrated that silver NPs inhibited the caspase-dependent pathway, determined by increased levels of PARP (poly (ADP-ribose) polymerase) cleavage. In this study, we suggest that silver NPs induce apoptosis in human lung cancer cells by attenuation of oxidative stress in lung cancer cell line and ROS-dependent Ras signaling which involves CREB signaling pathways and may be useful as a therapeutic strategy for 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 4785. doi:10.1158/1538-7445.AM2011-4785
Abstract 4787: MMP-2 RNA interference leads to decreased NF-κB activation and induced JNK-mediated apoptosis by modulating TRADD-TRAF2-FADD interactions in glioma
Authors: Kesanakurti Divya , Chetty Chandramu , Bhoopathi Praveen , Lakka Sajani S. , Gorantla Bharathi , Tsung Andrew J. , Rao Jasti S.
Published: June 2012

MMP-2 belongs to a family of extracellular matrix metalloproteinases (MMPs) that play a pivotal role in the degradation of the ECM, thereby enhancing the invasive and metastatic potential of cancer cells. Our study unveiled a new mechanism of how MMP-2 RNA interference inhibits NF-κB activation. Essentially, siRNA against MMP-2 (pM) modulated the interactions between the adaptor protein TRADD-TRAF2 and TRADD-FADD, which consequently hindered the nuclear localization and DNA binding activity of NF-κB. This, in turn, led to apoptosis. Furthermore, pM treatment led to RIP cleavage and remarkable increases in the expression levels of FADD and activated MAP kinases, p38 MAPK and JNK. The prolonged activation of JNK resulted in phosphorylation of c-Jun. Treatments with specific JNK1 inhibitor (SP600125) reduced and significantly reversed the pro-apoptotic effect of pM, thereby suggesting a role of JNK in pM-induced cell death. Supplementation of recombinant human MMP-2 to pM-transfected cells restored the inhibited DNA binding activity of NF-κB and rescued cells from the pro-apoptotic effect of pM. Here, we demonstrate that the simultaneous inhibition of NF-κB activation and sustained activation of JNK play significant roles in pM-mediated apoptosis in human xenograft glioma cells. In addition, our results show that the specific downregulation of MMP-2 diminished intracranial tumor growth in vivo. The inhibition of tumor growth after pM treatment was associated with decreased MMP-2 expression, inhibited NF-κB activation, and enhanced phospho-JNK levels. In conclusion, the present study elucidates an underlying mechanism of pM-induced cell death in vitro as well as decreased tumor development in vivo.

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 4787. doi:10.1158/1538-7445.AM2011-4787
Abstract 4788: Protein kinase CK2 modulates TAp73 phosphorylation and suppresses apoptosis in head and neck cancer
Authors: Lu Hai , Brown Matthew , Hu Michael , Unger Gretchen , Van Waes Carter , Chen Zhong
Published: June 2012

The TP53 family member TAp73 has been shown to be pro-apoptotic and enhance chemosensitivity, but is inactivated in head and neck squamous cell carcinoma (HNSCC). We recently found that the inflammatory cytokine, TNFα, induces NF-κB activation and TAp73 nuclear export, which contribute to the suppression of TAp73 pro-apoptotic function. However, the intermediate signaling involved in TNFα regulated TAp73 inactivation and modulation of apoptosis has not been defined. Here, we found that TAp73 exhibits varying levels of phosphorylation in a panel of HNSCC cell lines. An inverse association between phospho- and total TAp73 protein expression was observed, suggesting that signal phosphorylation could contribute to TAp73 turnover. In response to TNFα treatment, phosphorylated TAp73 decreased in the nucleus while increasing in the cytoplasm, consistent with nuclear-cytoplasmic translocation. As we previously showed that protein kinase CK2 subunits are aberrantly overexpressed and promote IKK-NF-κB activation in HNSCC, we examined CK2 as a potential upstream regulator of TAp73 phosphorylation. Both CK2 inhibitor DMAT (2-Dimethy-lamino-4,5,6,7-tetrabromo-1H-benzimidazole) and CK2α siRNA inhibited TAp73 phosphorylation, as well as increased TAp73 mRNA and protein expression. Consequently, DMAT treatment increased the expression of TAp73 downstream pro-apoptotic genes, p21, PUMA and NOXA through increased TAp73 binding to the promoters of these genes. DMAT treatment and mutation of TAp73 phosphorylation sites increased p21 reporter activity. Furthermore, DMAT blocked cell cycle progression and proliferation, and increased apoptosis of HNSCC in vitro. Delivery of anti-CK2α/α′ oligodeoxy-nucleotide nanocapsules into HNSCC xenograft models significantly suppressed tumor growth, concomitant with decreased TAp73 phosphorylation, increased expression of TAp73, and target apoptotic proteins PUMA and NOXA. These results suggest that the aberrant activation of protein kinase CK2 could be one of the upstream signaling molecules modulating phosphorylation of TAp73, TAp73 nuclear exportation, and suppression of apoptosis in HNSCC cells.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 4788. doi:10.1158/1538-7445.AM2011-4788
Abstract 479: Targeting tumor initiating cells inhibits tumor growth and serial transplantation ability in soft-tissue sarcomas
Authors: Wei Qingxia , Wang Chang Ye Yale , Zheng Feifei , Zhang Phil , Wang Weishi , Wunder Jay S. , Alman Benjamin A.
Published: June 2012

Tumors contain heterogeneous cell populations. There is a subpopulation of cells enriched for tumor initiating potential in sarcomas, which excludes Hoechst dye, and resides in the “side population” when subjected to flow cytometry (SP cells). These cells possess multi-potent differentiation potential, and as such they behave as “cancer stem cells” (CSCs), while the remainder of tumor cells act as “transient amplifying” cells. Because traditional cancer therapies may not target these tumor initiating cells, the persistence of SP cells could be responsible for relapse or a failed response to therapy. To detect signaling pathways that are differentially regulated in SP cells versus the remainder (non-SP) of the cells, we used gene profiling by microarray to compare their differences. RNA expressions were compared between these two cell populations from six malignant fibrous histiocytoma (MFH) samples using microarray. Differentially regulated genes were then analyzed by compiling a list of genes that showed a fold change greater than 1.25 in at least five of the six samples all in the same direction, and identifying if the list is enriched for genes involved in common molecular pathways, using Genespring® analysis tool. Two of the differentially regulated pathways detected were the Hedgehog signaling pathway and the Notch signaling pathway. Differential target gene expression for both pathways was verified using quantitative PCR. Triparanol (an agent that inhibits hedgehog signaling) and DAPT (an agent that inhibits Notch signaling) were used to treat eight primary MFH xenografts established in NOD-SCID mice. The xenografts produced visible tumors six weeks after subcutaneous transplantation, after which the mice were treated with one of the agents or a carrier as a control. At the end of the treatment, the tumors were harvested; their growth and SP% were assessed and compared; and the cells harvested from the treated xenografts were again implanted into mice to study the rate of re-growth upon secondary transplantation. Both triparanol and the Notch blocker DAPT treatment suppressed these pathways in tumor cells, depleted the abundance of SP cells, and reduced tumour growth. Intriguingly, treatment substantially inhibited the tumour-initiating potential of the treated sarcoma cells upon secondary transplantation. The data provides support that SP cells act as tumour initiating cells in sarcomas and shows that targeting the SP (in this case by targeting the Hh and Notch pathways) is an enticing approach for sarcoma therapy.

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 479. doi:10.1158/1538-7445.AM2011-479
Abstract 4793: Aberrant methylation of CDH1 correlates with poor prognosis in patients with head and neck squamous cell carcinoma
Authors: Rivera-Peña Bianca L. , Baez Adriana
Published: June 2012

Objective: CDH1 codes for E-cadherin, a key adhesion molecule of epithelial cells, whose loss of expression has been associated with carcinogenesis in several types of cancer. Promoter hypermethylation of CDH1 results in loss of expression of E-cadherin and may be involved in the development of metastasis and a poorer prognosis. The purpose of this study was to determine the methylation profile of CDH1 in a cohort of HNSCC patients and evaluated its association with clinicopathological parameters.

Methods: CDH1 methylation status was determined using the Methylight assay in a cohort of 59 patients that had CDKNA (p16) methylation status assessed previously. Correlations between clinical parameters and methylation profiles were statistically analyzed using Fisher's exact test and chi-square test when appropriate.

Results: Aberrant methylation of CDH1 was detected in 78% of the cases analyzed. In 33% of the patients had also CDKN2A aberrantly methylated. Most patients (69%) with CDH1 aberrantly methylated were in advanced stages of the disease (III/IV). They also had a poorer survival rate. No statistically significant association was found between CDH1 hypermethylation and gender, age, risk factors and staging.

Conclusion: CDH1 aberrantly methylated was detected at early and late stages of the disease. These results suggest that CDH1 hypermethylation may have a role in the initiation and in progression of HNSCC and potentially reduce the survival of HNSCC 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 4793. doi:10.1158/1538-7445.AM2011-4793
Abstract 4795: The epigenetic regulation of HPP1 expression in colon cancer
Authors: Wang Jian , Elahi Abul , Hernandez Jonathan , Clark Whalen , Achille Alex , ED Seto , Shibata David
Published: June 2012

Background: Tumors often are associated with aberrant epigenetic gene silencing. HPP1, a tumor suppressor gene, is epigenetically silenced by promoter methylation in a number of tumor types including colon cancer however, the contribution of histone acetylation is not clear. Moreover, c-myc interaction with the HPP1 promoter is thought to suppress expression. The purpose of this study is to examine the interplay between c-myc, DNA methylation and histone acetylation in the epigenetic regulation of HPP1 expression.

Methods: The HPP1-negative cell line, HCT-116, was treated with the DNA methylation inhibitor 5-aza-2’-deoxycitidine (5-aza-DC) and/or HDAC inhibitors, including sodium butyrate (SB), Vorinostat (SAHA), trichostatin A (TSA), and valproic acid (VPA). Knockdowns of c-Myc and HDAC-3 were performed using siRNA. Protein and mRNA expression of HPP1 were determined by Western Blot and RT-PCR respectively. HPP1 promoter methylation was assessed by real-time methylation-specific PCR. Furthermore, Chromatin immunoprecipitation (ChIP) experiments were used to demonstrate the binding of c-Myc to the HPP1 promoter.

Results: 5-aza-DC (0.4uM) as well as the HDAC inhibitors, SB (5mM), TSA (200nM), SAHA (5uM) and VPA (2mM), increased the expression of HPP1 in HCT-116 cells. The treatment of 5-aza-DC in combination with individual HDAC inhibitors resulted in a synergistic effect on increasing HPP1 expression as detected by both RT-PCR and Western blotting. We found that SAHA reduced the expression of HDAC-3 and c-Myc. Concordantly, knockdown of c-Myc and HDAC-3 by siRNA significantly enhanced HPP1 expression. We have also confirmed that c-Myc binds to the HPP1 promoter and its knockdown results in a reduction of HPP1 promoter methylation.

Conclusions: These results indicate that c-Myc- and HDAC-3-associated promoter methylation and histone deacetylation contribute to HPP1 epigenetic silencing. Colon cancer cells treated with DNA methylation and HDAC inhibitors can re-express the cancer suppressor gene HPP1. This study supports the conept that 5-aza-DC and HDAC inhibitors represent potentially promising classes of anticancer drugs for the future treatment of colon 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 4795. doi:10.1158/1538-7445.AM2011-4795
Abstract 48: Detecting and controlling for physical contamination in next-generation sequencing cancer studies
Authors: Cibulskis Kristian , McKenna Aaron , Fennell Tim , Getz Gad
Published: June 2012

All large-scale cancer genome characterization efforts rely on the unprecedented throughput of massively parallel sequencing technologies, such as Illumina/Solexa, ABI/SOLiD, Roche/454, and others to generate short sequence reads. In turn, this has spurred the development of novel algorithms for sequence alignment and detection of DNA alterations. Particularly in cancer genome studies, these detection algorithms must be exceedingly sensitive since the events of interest are present in just a fraction of the observed data due to stromal contamination and tumor ploidy. At the same time they must be very specific, since the events are also extremely rare.

Little has been published on tools to measure and control the quality of such data and in particular tools for identifying contamination of the sequenced DNA with DNA originating from different individuals than intended. In the case of cancer genome studies, contamination of this kind can lead to seemingly somatic events.

We have developed and made available a novel tool, called ContEst, for estimating the level of contamination in next generation sequencing data of human samples. We demonstrate ContEst's accuracy across a range of contamination levels, sources and read depths using sequencing data that were mixed in-silico at known concentrations.

Finally, we will show the effect of physical contamination by different individuals with regard to somatic mutation detection, and present strategies for compensating in the contaminated data.

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 48. doi:10.1158/1538-7445.AM2011-48
Abstract 4802: Cat eye syndrome chromosome region, candidate 1 (CECR1) is overexpressed and hypomethylated in salivary gland adenoid cystic carcinoma
Authors: Shao Chunbo , Tan Marietta , Glazer Chad A. , Bhan Sheetal , Chang Xiaofei , Uemura Mamoru , Kim Myoung S. , Moskaluk Christopher , Sidransky David , Califano Joseph A. , Ha Patrick K.
Published: June 2012

BACKGROUND and PURPOSE: Salivary gland adenoid cystic carcinoma (ACC) is the second most common malignancy of the salivary glands. It is characterized by a heterogeneous morphology, perineural invasion, and a variable clinical course. The molecular mechanisms underlying ACC are still unknown. We previously developed a high-throughput integrative epigenomic screening method to discover novel proto-oncogene candidates in ACC. With this screening method, we found that cat eye syndrome chromosome region, candidate 1 (CECR1) was a promising oncogene candidate for ACC. CECR1 encodes a member of a subfamily of the adenosine deaminase protein family and acts as a growth factor through its adenosine deaminase activity. No previous studies have correlated CECR1 in human cancers. In the current study, we validated several features of CECR1 in primary ACC samples, including promoter methylation status and expression levels.

METHODS and RESULTS: Bisulfite genomic sequencing was first employed to analyze the DNA methylation levels in the promoter of CECR1 in four ACC samples and four normal salivary gland tissues. Decreased methylation in CECR1 was found in three out of four ACC samples compared to zero out of four normal tissues. Secondly, quantitative methylation specific PCR (qMSP) was performed in a larger ACC cohort including 15 ACCs and 18 normal tissues. Consistent with the bisulfite genomic sequencing results, significant demethylation of CECR1 was detected in ACC samples (methylation levels ranged from 0.1 to 300.1; median, 19.8) compared to normal tissues (range from 10.2 to 600.0; median, 235.6), p < 0.05. Thirdly, we induced global demethylation in an ACC cell line, ACC83, by 5-aza-2′-deoxycytidine/ trichostatin A (5 Aza dC/TSA) treatment. Quantitative reverse transcription PCR (qRT-PCR) showed that CECR1 was significantly re-expressed in 5 Aza dC/TSA treated cell lines. Lastly, we analyzed the expression levels of CECR1 by qRT-PCR in the same ACC cohort. We found significant overexpression of CECR1 in ACCs compared to normal salivary tissue, p < 0.05.

CONCLUSIONS: This is the first study to associate elevated CECR1 levels with salivary gland ACC. The transcription of CECR1 appears to be upregulated by promoter demethylation. Both overexpression and promoter hypomethylation of CECR1 are hallmarks of ACC. CECR1 might play an important role in salivary gland ACC.

FUTURE DIRECTIONS: Functional studies of CECR1's role(s) in the carcinogenesis of salivary gland ACC are underway.

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 4802. doi:10.1158/1538-7445.AM2011-4802