bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 3376: Cord blood stem cells revert EMT to MET in glioma stem cells by downregulating synergistic transcriptional activation of Sox2 and Twist1
Authors: Velpula Kiran Kumar , Dasari Venkata Ramesh , Tsung Andrew J. , Dinh Dzung H. , Rao Jasti S.
Published: August 2012

The dynamic nature of cancer stem cells that underlie metastasis or their ability to switch between different cellular identities, as in epithelial to mesenchymal transition and mesenchymal to epithelial transition has profound implications for cancer therapy. The functional relationship between molecules involved in cancer cell stemness and metastasis is not clear. In this regard, our studies on human glioblastoma tissue grade IV specimens showed significant expression of Twist1 and Sox2, known mesenchymal and stemness related markers, respectively, indicating their association with glial tumorigenesis and metastasis. The glioma stem cells obtained from CD133+ cells demonstrated increased expression of Twist1 and Sox2 accompanied by significant increase in the mesenchymal markers such as N-cadherin, vimentin and β-catenin. Our studies on glioma stem cells treatment with human umbilical cord blood derived mesenchymal stem cells, showed down regulation of Twist1 and Sox2 proteins, apart from other mesenchymal stem cell markers. Based on the in vitro experiments and in vivo intracranial xenograft mouse model studies we elucidated the potential therapeutic role of hUCBSC in suppressing glioma cancer stemness by the induction of mesenchymal to epithelial transition.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 3376. doi:1538-7445.AM2012-3376
Abstract 3377: Oncolytic herpes simplex virus treatment of malignant peripheral nerve sheath tumor (MPNST) cancer stem-like cell orthotopic tumor model
Authors: Antoszczyk Slawomir J. , Rabkin Samuel D.
Published: August 2012

Malignant peripheral nerve sheath tumors (MPNST) are highly aggressive soft tissue sarcomas arising in peripheral nerves that often occur in patients with neurofibromatosis type 1 (NF1) and have an extremely poor prognosis. Therapy consists of surgery followed by radiation and/or chemotherapy, which are generally of limited efficacy. Cancer stem cells are a subpopulation of tumor cells with stem cell like properties that are thought to be important in tumor progression, resistance to therapy, and metastasis. We have isolated MPNST cancer stem-like cells (MSLCs) from a human MPNST cell line by non-adherent sphere-culture in neurosphere media with EGF and bFGF (without serum). Implantation of the MSLCs in the sciatic nerve generates an orthotopic MPNST model in athymic mice. As the tumors grow, mice develop neurologic deficits that are quantified using a neurologic scoring system and externally measurable masses. As a novel therapeutic strategy we are using oncolytic herpes simplex virus (oHSV) vectors, which replicate in and kill tumor cells but not normal tissue. Tumor selectivity is engendered by mutating viral genes that make virus replication non-permissive in ‘normal’ cells, while retaining permissivity in cancer cells. For these studies, we used G47α, a multi-mutated oHSV with deletions in the α34.5 and ICP47 genes and an inactivating LacZ insertion in the ICP6 gene. G47α is very efficacious in many tumor models and is currently in clinical trial for glioblastoma. G47α was able to infect and spread in MSLCs in vitro and MSLC-derived tumors in vivo. Treatment of established MSLC-derived sciatic nerve tumors with a single intratumoral injection of G47α significantly prolonged survival of mice and reduced neurologic deficits. There was no difference in survival between mice treated with 2 x 10^5 pfu versus 2 x 10^6 pfu, although the mice receiving the higher virus dose had significantly higher neurologic score (less deficit). We describe a new preclinical MPNST model generated by implantation of human MSLCs into the sciatic nerve of immune-deficient mice. Treatment of established tumors by oHSV G47α is highly efficacious. These preclinical studies suggest that oHSV should be considered for the treatment of patients with MPNST.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 3377. doi:1538-7445.AM2012-3377
Abstract 3378: Metformin protects head and neck cancer stem cells against DNA damage induced apoptosis
Authors: Kuo Selena Z. , Honda Thomas K. , Abhold Eric L. , Wang-Rodriguez Jessica , Altuna Xabier , Ongkeko Weg M.
Published: August 2012

The cancer stem cell hypothesis posits that within a tumor exists a distinct subpopulation of cells responsible for tumor initiation, progression, and maintenance. These cancer stem cells (CSCs) tend to be resistant to conventional chemotherapy and, like normal stem cells, possess the ability to self-renew and differentiate, thereby effecting tumor recurrence. Metformin, the most widely prescribed drug for the treatment of diabetes, has received attention in recent years as a potential anticancer agent capable of targeting cancer stem cells through such means as inhibiting cell proliferation and abrogating chemo-resistance. In the current study, we sought to determine the effects of Metformin on a putative head and neck squamous cell carcinoma (HNSCC) cancer stem cell culture. In contrast to the findings of previous studies, our data suggests that Metformin promotes properties of a cancer stem cell phenotype in HNSCC in vitro. Treatment with Metformin resulted in a dose-dependent induction of the stem cell genes CD44, BMI-1, Oct-4, and Nanog, as measured by qPCR. These results were supported by immunofluorescence data. Metformin treatment promoted self-renewal capacity of HNSCC stem cells, as demonstrated by the increase in size and number of tumorspheres formed in non-adherent and non-differentiating conditions. At various doses, treatment with Metformin alone had no effect on cell proliferation, as measured by MTS assay. Furthermore, when administered in combination with cisplatin, Metformin significantly protected against cisplatin-induced cell death, as demonstrated by MTS and TUNEL assays. Immunoblot experiments demonstrating a decrease in Akt phosphorylation upon treatment with Metformin suggests Metformin-mediated cytoprotection is independent of the Akt pathway. Other possible mechanisms are currently under investigation, including Metformin's ability to regulate autophagy. Although further in vivo studies are necessary, taken together, our findings suggest that Metformin may not be an effective therapeutic option for patients with HNSCC.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 3378. doi:1538-7445.AM2012-3378
Abstract 3380: Comparison proteome analysis of scirrhous gastric carcinoma stem cell-like SP and hypoxia-resistant cell lines
Authors: Morisaki Tamami , Yashiro Masakazu , Kakehashi Anna , Okita Yoshihiro , Fukuoka Tatsunari , Aomatsu Naoki , Yoshii Mami , Hasegawa Tsuyoshi , Matsuoka Junko , Nagahara Hisashi , Kimura Kenjiro , Noda Eiji , Amano Ryosuke , Kubo Naoshi , Tanaka Hiroaki , Muguruma Kazuya , Yamada Nobuya , Maeda Kiyoshi , Nakata Bunzo , Ohira Masaichi , Wanibuchi Hideki , Hirakawa Kosei
Published: August 2012

Intro Cancer stem cells (CSCs) are considered to be responsible for cancer metastasis, and hypoxia is supposed to be an important regulator of CSCs differentiation. Furthermore, tumor hypoxia was reported to be associated with more aggressive tumor phenotypes such as high metastatic ability and resistance to various anti-cancer therapies which may lead to a poorer prognosis. This raises the question of whether there might be proteins representing similar alterations which are responsible for the correlation between hypoxic and CSCs phenotypes. We have established a diffuse-type of gastric carcinoma cell line (OCUM-12), and a hypoxia-resistant cancer cell line (OCUM-12/Hypo) cloned from parent OCUM-12 cells by continuous exposure to 1% oxygen. The side population (SP), as evaluated by a flow cytometric analysis using Hoechst 33342, has been known as CSC-rich population. To investigate and compare the proteomes of the hypoxic (OCUM-12/Hypo), stem cell (OCUM-12SP) and parent OCUM-12 diffuse-type gastric carcinoma cell lines, protein lysates from those cell lines were analyzed using QSTAR Elite LC MS/MS. Method Triplicate pooled samples (10 ug protein each) from stomach cancer cell lines were prepared and labeled with iTRAQ reagents. MS/MS data were searched against the Swiss Protein database (HUMAN) using ProteinPilot™ 2.0 software (AB Sciex). The Ingenuity Pathway analysis program was utilized, to assign biological significance, and to identify networks of interacting differentially expressed proteins, functional groups and pathways. Result In both OCUM-12SP and OCUM-12/Hypo cells, significant overexpression of Wnt signaling pathway was obvious. Furthermore, elevation of MTHFD1, a protein controlling histidine and purine nucleotide metabolism, cytokeratins 18 (CK18), and 19 (CK19) regulating cell cycle, apoptosis and angiogenesis, transcriptional regulator ANP32A, and cellular chaperones heat shock proteins A9 and STIP was observed as compared to the parent OCUM-12 cell line. Furthermore, anterior gradient homolog 2 (AGR2)was down-regulated in both cell lines. Conclusion Wnt signal, MTHFD1, CK18, CK19, ANP32A, HSPA9 and STIP, AGR2 might be responsible for the stem-like phenotype, hypoxia resistance and higher invasiveness of gastric cancer.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 3380. doi:1538-7445.AM2012-3380
Abstract 3841: HIF-143, a novel inhibitor of complex III, inhibits pancreatic cancer growth by suppressing reactive oxygen species production and epidermal growth factor signal
Authors: Kim Se Nyun , Han Youn Ho , Kang Dae Pill , Park Sung Ho , Kim Jung-Ho , Kim Se Won , Kim Jung Keun
Published: August 2012

Reactive oxygen species have been considered as a therapeutic target for cancer treatment. In this study, we characterized the anticancer activity of novel small molecule inhibitor of cytochrome bc1, HIF-143, in pancreatic cancer. HIF-143 shares common structural moiety with known cytochrome bc1 Qo inhibitors including azoxystrobin and E-α-methoxyacrylate-stilbene. HIF-143 inhibits reduction of cytochrome c by purified mitochondria in the presence of rotenone and induction of reactive oxygen species by hypoxia or epidermal growth factor in cellular context. HIF-143 also suppresses activation of EGFR and downstream ERK and AKT induced by EGF treatment. EGF-induced transcription was also inhibited by HIF-143. Interestingly, these effects were synergistic when combined with EGFR inhibitor such as Erlotinib and Gefitinib. Cell proliferation, survival, and anchorage-independent growth were also synergistically inhibited by HIF-143 and Erlotinib. HIF-143 also inhibited pancreatic tumor growth in BxPC-3 human pancreatic cancer xenograft model. The inhibition of tumor growth was much higher when animals were treated with both HIF-143 and Erlotinib than individual treatment, suggesting synergistic anticancer activity in vivo. In addition, when HIF-143 was combined with Erlotinib and Gemcitabine, anticancer efficacy was increased without the increase of sign of toxicity, showing addition of HIF-143 can give clinical benefit to pancreatic cancer patients. Toxicological study showed that combination of HIF-143 and Erlotinib is safe enough with safety margin higher than 6-fold. These findings suggest that pharmacological targeting of complex III might be a promising approach to treat pancreatic cancer. These results provide scientific rational for testing of HIF-143 in the clinical trial to develop as a novel anticancer drug.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 3841. doi:1538-7445.AM2012-3841
Abstract 3843: Targeting FACT complex suppresses mammary tumorigenesis in Her2/neu transgenic mice
Authors: Gurova Katerina V. , Garcia Henry , Commane Mairead , Safina Alfiya
Published: August 2012

We have recently found that expression of Facilitates Chromatin Transcription (FACT) complex consisting of SSRP1 and SPT16 protein subunits is elevated in many types of cancer comparing with normal tissues. Moreover, survival of tumor cell, but not normal cells is significantly compromised upon genetic knockdown of any of the FACT subunits. In our recent studies we have shown that FACT is essential for the transcriptional activity of NF-κB and Heat Shock Factor 1 and identified small molecules that inhibit activity of both transcription factors by causing functional inactivation of FACT. Since both NF-kB and HSF1 are activated in the process of transformation, we proposed that FACT may be involved in tumor transformation and that inhibition of FACT activity may prevent or reduce tumorigenesis. Objectives of our study were: (i) to check if FACT level is changed in the process of oncogene-induced transformation in vitro and in vivo; and (ii) to test safety and efficacy of anti-FACT therapy with Curaxin-137 in prevention of tumor formation in mice prone to cancer due to oncogene overexpression. We used in vitro (Ha-ras12V) and in vivo (MMTV-neu transgenic mouse model) models of transformation to monitor changes in FACT subunits. We treated the MMTV-neu transgenic mice, in which mammary carcinomas are spontaneously developed due to estrogen receptor-regulated expression of the Her2 proto-oncogene, with Curaxin-137 to determine whether the drug has any toxic effect on normal tissues and/or impact on mammary carcinogenesis. Expression of FACT was elevated in the process of transformation in all models tested. Chronic administration of Curaxin-137 to MMTV-neu mice at doses not having any toxic effect, inhibited tumor onset, delayed tumor progression, and prolonged survival of mice in a dose-dependent manner. Curaxin-137 induced much stronger changes in FACT in tumors than in normal organs, expressing FACT (spleen). Thus, Curaxin-137 may be considered as a potential preventive and/or early stage therapeutic agent for breast cancer.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 3843. doi:1538-7445.AM2012-3843
Abstract 3846: Vitamin D3 potentiates the antitumor effects of arsenic trioxide in human leukemia (HL-60) cells
Authors: Rogers Christian , Yedjou Clement , Tchounwou Paul
Published: August 2012

Arsenic trioxide (ATO) is an innovative form of therapy that has recently been found to benefit acute promyelocytic leukemia (APL) patients. Our laboratory has demonstrated that ATO stimulates oxidative stress therefore causing ATO-induced cytotoxicity in human leukemia (HL-60) cells. Pro-oxidants have been known to play a role in free radical-mediated oxidative stress. Vitamin D3, an active metabolite of vitamin D, inhibits the growth of a number of cancer types such as prostate, breast, colorectal, leukemia, and skin cancers. The specific aim of this research was to determine whether co-exposure to vitamin D3 increases the efficacy of ATO through cytotoxicity, oxidative stress and apoptosis associated with increased ATO toxicity in human leukemia (HL-60) cells. In our current investigation, we performed the MTT assay and trypan blue exclusion test to measure cell viability. We also performed the lipid peroxidation assay to determine the levels of malondialdehyde (MDA) production in HL-60 cells co-exposed to ATO and vitamin D3 in combination. The results of trypan blue exclusion and MTT assay indicated that vitamin D3 exposure potentiates the toxic activity of ATO in HL-60 cells in a dose dependent manner. Co-administration of vitamin D3 and ATO resulted in a significant (P<0.05) increase in MDA level compared to ATO alone. A statistically significant and dose-dependent increase (p <0.05) was recorded in annexin V positive cells (apoptotic cells) with increasing doses of vitamin D3 in ATO-treated cells. This finding was confirmed by the result of DNA laddering assay showing clear evidence of DNA fragmentation in ATO and vitamin D3 treated HL-60 cells. Overall, the present study indicates that vitamin D3 potentiates the antitumor effects of ATO at least part, via cytotoxicity, oxidative stress, nucleosomal fragmentation and phosphatidylserine externalization.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 3846. doi:1538-7445.AM2012-3846
Abstract 3852: Improved coiled-coil design enhances interaction with Bcr-Abl and induces apoptosis
Authors: Miller Geoffrey D.
Published: August 2012

The fusion protein Bcr-Abl responsible for the oncogenic activity in chronic myelogenous leukemia (CML) depends heavily on oligomerization for function. Formation of Bcr-Abl oligomers occurs through a coiled-coil domain existing at the N-terminal portion of the Bcr segment. Previously, we have shown that disruption of this oligomerization utilizing a modified coiled-coil domain (CCmut2) both decreases the proliferation of CML cells and results in the induction of apoptosis. An important contributing factor to these results stems from the increased destabilization of CCmut2 homo-dimers. This phenomenon occurs due to the rationally mutated residues in the modified coiled-coil which allow for favorable interactions with the wild-type Bcr-Abl, but destabilizing interactions with other CCmut2 molecules, thus discouraging the formation of CCmut2 homo-dimers. In turn, this increases the availability and affinity for the modified coiled-coil to interact with and inhibit endogenous Bcr-Abl in CML cells. An additional mutation (K39E) was included that could potentially further destabilize the mutant homo-dimer. Added to the other mutations found in CCmut2 (C38A, S41R, L45N, E48R, Q60E), the new construct was termed CCmut3. To show that CCmut3 results in enhanced binding to a wild-type coiled-coil domain (representative of endogenous Bcr-Abl), 2 separate assays were performed. Colocalization studies were used to show the degree to which CCmut3 localizes intracellularly with Bcr-Abl. Additionally, a mammalian two-hybrid assay was conducted to show the relative selective dimerization between CCmut3 and the Bcr-Abl coiled-coil. Next, caspase 3/7 assays were performed and showed the ability of CCmut3 to induce apoptosis. The CCmut 3 also showed nuclear segmentation (a measurement of late-stage apoptosis) and decrease in oncogenic proliferation (via the colony forming assay). Taken together, these results provide strong evidence for using CCmut3 as a therapeutic for CML. Lastly, attempts to truncate the CCmut3 to find the smallest possible sequence needed (e.g., helix 2) to bind and kill cells effectively is currently underway.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 3852. doi:1538-7445.AM2012-3852
Abstract 3854: Gamma-linolenic Acid (GLA) sensitizes pancreatic cancer cells to gemcitabine
Authors: Lupu Ruth , Busby Robert , Cheol Park-Hong , Espinoza Ingrid
Published: August 2012

Pancreatic cancer is the fourth leading cause of cancer deaths in the United States and continues to be a disease with few options for treatment. Current therapeutic regimens for pancreatic cancer often include the nucleoside analog gemcitabine (GEM), but while it has been in use for many years, the overall five year survival rate continues to be about 5%. New therapies are urgently needed to treat this disease. The nutritional supplement gamma-linolenic acid (GLA) is a poly-unsaturated fatty acid (PUFA) of the n-6 PUFA family, and has garnered attention for its cytotoxic effects against tumor cell lines while not affecting normal cells. In this study we look at the effect GLA has on Panc-1 cells and its ability to increase the sensitivity of these cells to treatment with GEM. Through the use of cell viability assays, immunofluorescence, 3-D growth assays, and western blotting, our results show that GLA alone will inhibit growth and induce apoptosis in Panc-1 cells. When GLA is combined with GEM, the results are synergistically enhanced. In addition, our results show that GLA may act through disruption of lipid rafts in the cellular membrane and may activate the extrinsic apoptotic pathway causing cell death. These results suggest that the nutritional supplement GLA could be used in combination with GEM to increase the therapeutic effectiveness of GEM while treating pancreatic cancer.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 3854. doi:1538-7445.AM2012-3854
Abstract 3859: Multivalency of non-peptide integrin αVβ
3 antagonist slows tumor growth
Authors: Kim Yoo-Shin , Li Feng , O'neill Brian E. , Li King CP , Li Zheng
Published: August 2012

To date, more than 200 angiogenesis inhibitors have been reported. These include only a few antiangiogenic peptide drugs. In addition, many molecules upregulated on angiogenic endothelial cells have been explored in the past decades. One of these is integrin αvβ3, which recognizes RGD (Arg-Gly-Asp) motifs in extracellular protein components. Targeting the αvβ3 integrin with drugs may provide an opportunity to destroy tumor vessels without harmful effects on microvessels of normal tissues. Multivalency is a strategy for increasing the binding affinity of compounds ostensibly to increase their potency or imaging potential. Surprisingly, multivalent versions of successful drugs showing enhanced binding have not always demonstrated enhanced therapeutic efficacy. For example, multivalent RGDs have not generally shown better therapeutic efficacy. In our study, we prepared a multivalent nonpeptide integrin αvβ3 antagonist (multivalent IA, 4-[2-(3,4,5,6-tetrahydropyrimidine-2-ylamino)ethyloxy]benzoyl-2-(S)-aminoethylsulfonyl-amino-halanine monomer, dimer and trimer) for anti-tumor therapy. The anti-tumor efficacies of the IA multivalent compounds were evaluated in B16F10 melanoma tumor-bearing mice. Tumors were inoculated subcutaneously and allowed to progress before treating. IA compounds were given by intraperitoneal injection every 12 hours for 14 days. It was observed that 30 mg/kg of IA-trimer showed higher antitumor efficacy and lower toxicity compared to IA-Monomer and IA-Dimer, as shown by changes in tumor volume against control group (IA-Trimer, 32.05 % > IA-Dimer, 45.33 % > IA-Monomer 59.29 %). Based on these results, we conclude that the success of a multivalent strategy depends on the details of the individual components and how they are put together. This may be the first αvβ3 multivalent ligand showing clear enhancement in anti-tumor effectiveness.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 3859. doi:1538-7445.AM2012-3859
Abstract 386: Differential roles of uPAR in peritoneal ovarian carcinomatosis: the inflammatory link
Authors: Said Neveen A. , Al-Hassan Nada , Ivanova Vessela S. , Syed Viqar , Motamed Kouros
Published: August 2012

Epithelial Ovarian cancer is the 4th leading cause of death from gynecologic malignancies in the United States. More than 75% of patients are diagnosed at late stages, with the solid tumor masses growing either as peritoneal implants, or floating within the ascitic fluid, a condition known as “peritoneal ovarian carcinomatosis (POC)”. Despite aggressive surgical treatment “debulking” recurrence, with acquired chemo- and radio-resistance are frequent with poor 5-year survival rate. Efforts to improve survival rates are hindered by suboptimal compliance with strategies that can detect, and effectively treat ovarian cancer in its early stages. A number of factors have been implicated as mediators POC, including integrins, growth factors, and proteases. The urokinase plasminogen activator receptor (uPAR) which is multifunctional receptor involved in a myriad of tumor cell processes, including invasion, ECM remodeling, adhesion, migration, angiogenesis, and metastasis. However the role of uPAR in modulating the inflammatory ovarian cancer microenvironment is still elusive. To define the potential pro-inflammatory role of uPAR in ovarian cancer, first, we characterized its expression in human ovarian cancer tissue microarray and found the expression of tumor as well as stromal uPAR is significantly upregulated as a function of tumor grade and stage. Second, using a syngeneic murine model of POC injecting ID8 cells intraperitoneally in uPAR knockout mice, we found that genetic ablation of uPAR restrained tumor take, peritoneal implants and prolonged the survival of uPAR knockout mice compared to their wild type counterparts. Ascitic fluid accumulation was significantly decreased in uPAR knockout mice with significantly lower levels of soluble pro-inflammatory cytokines/chemokines and bioactive lipids (8-isoprostane and PGE2) compared to the wildtypes. In addition, absence of uPAR was associated with decreased tumor infiltrating and associated macrophages. Third, in vitro mechanistic studies revealed that both OvCa cell- and macrophage-uPAR contributed to OvCa cell invasiveness and secretion of inflammatory mediators. In summary, our studies indicated that uPAR plays a significant role in ovarian cancer cell-macrophage crosstalk and contributes to the inflammatory ovarian cancer microenvironment. This provides a rationale for targeting the uPAR with either specific neutralizing antibodies or targeting its downstream inflammatory effectors in patients with ovarian cancer.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 386. doi:1538-7445.AM2012-386
Abstract 3861: Fusion toxin BLyS-gelonin inhibits growth of B-NHL cell lines in vitro and in vivo
Authors: Luster Troy A. , Mukherjee Ipsita , Carrell Jeffrey A. , Cho Yun Hee , Gill Jeffrey , Garcia Andy , Ward Christopher , Ullrich Stephen , Migone Thi-Sau , Humphreys Robin
Published: August 2012

B lymphocyte stimulator (BLyS) is a member of the TNF superfamily of cytokines. BLyS is expressed by cells of myeloid origin and is one of many soluble factors that regulate human B-cell activation. The biological activity of BLyS is mediated by three cell surface receptors: B-cell-activating factor-receptor (BAFF-R/BR3), transmembrane activator and calcium modulator and cyclophilin ligand interactor (TACI) and B-cell maturation antigen (BCMA). These receptors are expressed by normal and malignant B-cells at various stages of development. To target malignant B cells expressing BLyS receptors, the recombinant plant-derived toxin gelonin was fused to the N-terminus of BLyS to generate the fusion toxin BLyS-gel. Gelonin is an N-glycosidase that removes a critical adenine from eukaryotic 28S rRNA, disrupting ribosome function and inhibiting protein synthesis. Importantly, gelonin is not toxic to cells unless coupled with a targeting moiety that can enter the cell. BLyS-gel was used to treat a panel of nearly 50 malignant non-Hodgkin lymphoma (NHL) cell lines expressing BLyS receptors. NHL subtypes mantle cell lymphoma (MCL), diffuse large B cell lymphoma (DLBCL) and B cell precursor-acute lymphocytic leukemia (BCP-ALL) were preferentially sensitive to BLyS-gel mediated cytotoxicity, with EC50 values in the low picomolar range. BLyS-gel cytotoxicity was mediated primarily by BR3 and TACI in sensitive cell lines; however, cell surface expression of these BLyS receptors did not necessarily confer sensitivity to BLyS-gel. The internalization of BLyS-gel was confirmed in both sensitive and resistant cell lines, indicating resistance was not due to a lack of internalization. As expected, BLyS-gel treatment inhibited protein synthesis in sensitive, but not resistant cell lines. In most cell lines, cell death seemed to be mediated by the “ribotoxic stress response.” This response involves activation of p38 MAPK and JNK/SAPK, and BLyS-gel mediated cytotoxicity was inhibited by the p38/JNK inhibitor SB203580. Finally, BLyS-gel treatment significantly prolonged survival in three distinct disseminated xenograft models (BCP-ALL, DLBCL & MCL) in SCID mice, and BLyS-gel was shown to specifically localize to sites of disease. Together, these findings suggest BLyS has potential as a targeting ligand for the therapeutic delivery of toxins and/or drugs directly to malignant B cells.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 3861. doi:1538-7445.AM2012-3861
Abstract 3862: The potential role of CD44 in liver regeneration
Authors: Lam CT , Yang ZF , Ng MN , Wan T , Lau J , Ho DW , Fan ST , Poon RT
Published: August 2012

Background and Aim: Liver regeneration occurs after liver damage by ischaemia, hepatitis, or in hepatocellular carcinoma (HCC) patients receiving hepatic resection or liver transplantation. Understanding the molecular bases of this process will provide novel therapeutic approaches for patients with various liver diseases. Previous studies suggested the linkage between CD44, a multifunctional cell surface receptor, and liver regeneration. The detailed role of this receptor in liver regeneration, however, remained unclear. The present study aimed at elucidating the role of CD44 in liver regeneration. Materials and Methods: A mouse model of liver regeneration induced by partial hepatectomy (PH) was employed. Serum and liver tissues were collected at different time points after PH. ELISA was performed to measure hyaluronic acid (ligand for CD44) level in serum. Flow cytometry was done to characterize liver cell populations after PH. Liver regeneration was quantified by measurement of liver mass and by immunohistochemical staining for PCNA (a proliferation marker). Quantitative PCR was performed to compare gene expression pattern of 46 genes between CD45− CD44+ cells and their CD44− counterparts. Results: Firstly, serum hyaluronic acid level was elevated at the early stage of liver regeneration. Secondly, by flow cytometry, an increase in CD45− CD44+ cell population was found. Thirdly, immunohistochemical analysis revealed active hepatocyte proliferation during this period. Interestingly, the hepatectomy-induced cell proliferation was suppressed after treating mice with anti-CD44 antibody, suggesting a functional role of CD44 in liver regeneration. Lastly, dysregulation of genes involving in cell proliferation, angiogenesis, and metabolism of hyaluronic acid was disclosed in CD45− CD44+ cells. Conclusion: The present study indicated that CD44-mediated pathways are required for liver regeneration, which may have therapeutic implications in treating liver diseases, including HCC.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 3862. doi:1538-7445.AM2012-3862
Abstract 3865: The rGel/BLyS fusion toxin enhances the therapeutic effects of bortezomib in in vitro and in vivo models of mantle cell lymphoma.
Authors: Lyu Mi-Ae , Pham Lan V. , Sung Bokyung , Tamayo Archito T. , Ahn Kwang Seok , Cheung Lawrence H. , Marks John W. , Ford Richard J. , Aggarwal Bharat B. , Rosenblum Michael G.
Published: August 2012

Mantle cell lymphoma (MCL) is an incurable, aggressive histo-type of B-cell non-Hodgkin lymphoma associated with both high relapse rates and relatively short survival. MCL is a therapeutic challenge and presents an opportunity for the application of novel, targeted agents. Because MCL over-expresses receptors for B lymphocyte stimulator (BLyS) and displays constitutively active NF-κB, agents targeting these pathways may be of therapeutic relevance in this disease. To explore the potential clinical use of the rGel/BLyS fusion toxin in combination with bortezomib in MCL, we evaluated this fusion toxin for its ability to inhibit MCL growth in a severe combined immunodeficiency (SCID) xenograft model. Compared with PBS-treated mice, mice treated with rGel/BLyS showed both prolonged median (84 d vs. 125 d) and overall survival (40%) (p=0.0027). Compared with bortezomib alone-treated mice, mice treated with rGel/BLyS plus bortezomib showed significant median (91d vs. 158d) and overall survival (20%) (p=0.0127). Histopathologic analysis of peritoneal intestinal mesentery from MCL-SCID mice showed no demonstrable microscopic lymphomatous involvement at 225 days after treatment with rGel/BLyS. Followup in vitro mechanistic studies demonstrated that the rGel/BLyS plus bortezomib combination resulted in an additive or a synergistic growth inhibition, reduction of NF-κB DNA-binding activity, inhibition of cyclin D1, Bcl-xL, p-Akt, and Akt and up-regulation of Bax. We additionally found that combination treatment caused induction of apoptosis associated with caspase-9, caspase-3 activation and PARP cleavage. rGel/BLyS is an effective therapeutic agent for both primary and savage treatment of aggressive MCL and may be an excellent candidate for clinical development. This research was conducted, in part, by the Clayton Foundation for Research and by a Translational Research Award (LLS 6234-07) from the Leukemia and Lymphoma Society.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 3865. doi:1538-7445.AM2012-3865
Abstract 3869: Proteomics highlights which G-protein coupled receptors are candidates for ADC development
Authors: Kast Juergen , Boyd Robert , Ackroyd James , Allen Jason , Anderson Amanda , Barnes Martin , Bozhenok Ludmila , Dusanjh Palminder , Hudson Lindsey , Yu Xiaohong , Aud Dee , Awdew Rahel , Bisht Arnima , Pandya Deepal , Trang Michael , Terrett Jonathan , Rohlff Christian
Published: August 2012

Antibody-drug conjugates (ADCs) are a recent and exciting development for targeted therapy of cancer. Their efficacy is governed by ADC-intrinsic characteristics such as avidity, drug load and linker chemistry, and mechanisms of activation and action, which can be controlled or clarified in the early stages of ADC development. In contrast, the properties that define a promising ADC target are still somewhat unclear. OGAP is a unique proteomic database that integrates information at the tissue, disease and protein isoform level across diseases, indications, and normal tissues to clarify protein expression levels and profiles. Specifically, it currently holds information on ∼2,000,000 human protein peptide sequences, ∼16,000 human proteins sequenced, ∼7,000 cancer membrane proteins, ∼50 tissues/organs, and ∼60 diseases. Building on OGAP and a proprietary sample preparation and processing workflow that relies on state-of-the-art high-throughput mass spectrometry and data processing to provide quantitative information on over 4,000 membrane-enriched proteins from ∼ 15,000 unique peptide sequences per analysis, we have established a novel predictive tool to establish each protein's potential to serve as a target for ADC development. The tool considers proteomic and target-specific information on antigenicity, structure, function, expression level, regulation, and tissue distribution in order to highlight the most suitable candidates for ADC development. We will demonstrate the utility of this process for the protein family of G-protein coupled receptors (GPCRs), which according to a recent bioinformatics prediction encompasses 899 distinct members in the human genome. These cell surface receptors are the target of more than one third of conventional drugs, yet their potential for ADCs is largely unexplored. Here we show that proteomics in the context of the OGAP database can highlight which of this large family of receptors have the potential to become true ADC targets.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 3869. doi:1538-7445.AM2012-3869
Abstract 387: PEDF binds to IL- 10 receptor in the absence of IL-10 and inhibits melanoma tumor growth
Authors: Khan Aslam A.
Published: August 2012

Macrophages exist within the tumor microenvironment and play an important role in influencing tumor cell growth, angiogenesis and cancer progression. The interaction between macrophages, tumor cells, and endothelial cells occurs largely through cytokine secretion and detection by tumor associated macrophages (TAM). In this study, we investigate the role of interleukin-10 (IL-10) and pigment epithelial derived factor (PEDF) in the macrophage-tumor interaction. In an explant model of melanoma, tumor growth was significantly reduced in IL-10 knockout mice. Media from IL-10 deficient macrophages significantly inhibited tumor cell proliferation when compared to media from wild-type macrophages. Interestingly, expression of the anti-tumor and anti-angiogenic cytokine PEDF was increased in IL-10 knockout macrophages. Media of IL-10 KO macrophages treated with recombinant IL-10 (rIL-10) and anti-PEDF failed to inhibit tumor cell proliferation. Neutralization of PEDF in IL-10 KO mice restored tumor growth in these mice. To further explore the molecular mechanisms of the interaction between PEDF, IL-10 and IL-10 receptor, IL-10 receptor binding of PEDF was evaluated in presence or absence of rIL-10. PEDF binds to IL-10 receptor only in the absence of competing rIL-10. Taken together these studies show a novel interaction between PEDF and the IL-10 receptor and suggest that the anti-tumor activity of PEDF can be significantly enhanced by reducing IL-10 levels.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 387. doi:1538-7445.AM2012-387
Abstract 3870: Construction and characterization of completely human serine protease therapeutics targeting Her2/neu
Authors: Cao Yu , Mohamedali Khalid A. , Chueng Lawrence H. , Hittelman Walter N. , Rosenblum Michael G.
Published: August 2012

The serine protease granzyme B (GrB) is a powerful enzymatic inducer of apoptosis via a multi-modal intracellular mechanism including direct activation of the caspase cascade, damaging mitochondria resulting in the release of cytochrome C, and damaging nuclear matrix. We developed a novel recombinant immunotoxin linking GrB to a humanized Herceptin-derived scFv (4D5) specific for the Her2/neu cell-surface domain. The GrB/4D5 fusion constructs were efficiently expressed in HEK 293T mammalian cells as active glycosylated molecules and purified by immobilized cobalt affinity chromatography. In vitro studies demonstrated that GrB/4D5 retained the affinity and specificity of the original Herceptin antibody with a Kd of 0.24nM, as well as the biological activity of GrB (BAADT assay, enzymatic activity of 2.08×105U/µM, vs 1.39×105U/µM for free GrB). Target cell-specific activity was observed with IC50 of 10 to 50nM against a panel of Her2/neu positive tumor cells. In addition, the rapid induction of apoptosis in cells was confirmed by Annexin V staining and detection of activated caspase-3 in the cytosol. GrB/4D5 was active against BT474 M1 parental cells as well as Herceptin-resistant cells, despite the fact that these cells were more than 150 fold resistant to Herceptin. Addition of EGF or NRG-1 had no inhibitory effect on the cytotoxicity of the fusion construct against BT474 M1 cells. This is the first report of GrB-based immunotoxins having the potential to overcome Herceptin resistance arising in breast tumor cells. Further in vitro characterization against Her2/neu positive cancer cells expressing MDR or MRP-related proteins and in vivo xenograft model studies are ongoing. Research conducted, in part, by the Clayton Foundation for Research.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 3870. doi:1538-7445.AM2012-3870
Abstract 3874: A novel human fusion protein composed of the serine protease Granzyme B and VEGF121 to target the vasculature of solid tumors
Authors: Mohamedali Khalid A. , Cheung Lawrence H. , Cao Yu , Rosenblum Michael G.
Published: August 2012

Targeting solid tumors and their metastases continue to be viewed as an essential aspect of therapeutic success to achieve long-term tumor control. Targeted therapy is a promising approach in this regard and the utilization of human proteins assures the potential for long-term therapy without immunological restrictions. VEGF121 is a naturally-occurring splice variant that binds to both VEGFR-1 and VEGFR-2 receptors over-expressed on the endothelium of tumor vasculature but not normal vasculature. The serine protease granzyme B (GrB) is capable of inducing intense cellular apoptosis through both caspase-dependent and caspase-independent multiple-cascade mechanisms. We expressed pro-GrB/VEGF121 in HEK293T cells and harvested the fusion protein under serum-free conditions. The purified protein expressed as a homodimer and Western blotting confirmed incorporation of both VEGF121 and GrB components into the construct. Comparison of GrB/VEGF121 with its expected molecular weight by SDS-PAGE suggests minimal (1-2 kDa) glycosylation. The enzymatic activity of GrB in GrB/VEGF121 was comparable to that of human GrB. The cytotoxicity of GrB/VEGF121 confirmed specific targeting and internalization into PAE/hVEGFR-2 (IC50 ∼ 10 nM), but not PAE/hVEGFR-1 cells (IC50 > 300 nM). GrB/VEGF121 induced apoptosis in PAE/VEGFR-2, but not PAE/VEGFR-1 cells, as determined by Annexin V staining. The targeting efficacy of GrB/VEGF121 against a panel of cells expressing a range of VEGFR receptor levels is under study. Studies investigating GrB/VEGF121 signaling events and in vivo efficacy against various tumor models are currently ongoing and will be presented. Research conducted, in part, by the Clayton Foundation for Research.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 3874. doi:1538-7445.AM2012-3874
Abstract 3876: Role of Stat3 transcriptional activation in a preclinical mouse model of prostate cancer and potential as a therapeutic target
Authors: De Velasco Marco A. , Tanaka Motoyoshi , Fujimoto-Ouchi Kaori , Moriya Yoichiro , Kura Yurie , Kobayashi Yasuki , Yamamoto Yutaka , Hatanaka Yuji , Kato Hiroyuki , Yoshikawa Kazuhiro , Nishio Kazuto , Uemura Hirotsugu
Published: August 2012

The transcription factor, Stat3, has been implicated in the growth and progression of several cancer types including lung skin, liver, ovarian, kidney, colon cancer and prostate. Stat3 has also been shown to induce the metastatic behavior of prostate cancer cells in vitro and in vivo. Activation of Stat3 occurs by the binding of various cytokines to its receptors leading to the activation of the JAK/Stat3 signaling pathway. Of these cytokines, interleukin-6 (IL-6) has been implicated in regulating growth of various malignant tumors and activated IL-6 has been shown to be elevated in the sera from patients with metastatic prostate cancer. In the present study we examined the IL6-induced Stat3 transcriptional activation in the development and progression of prostate cancer and its possible role as a target for the treatment of prostate cancer using the prostate-specific conditional targeting PTEN knockout mouse model. Homozygous PTEN-mutants develop prostate cancer in a stage-specific manner and have the ability to grow and develop castration-resistant prostate cancer after total androgen ablation by castration. ELISA assays revealed increased expression of soluble IL-6 receptor (IL-6R) in tissue lysates from prostate tumors in non-castrated and castrated mice (77.0 ± 6.17 vs 23.75 ± 5.17 ng/g of tissue, p<0.001, respectively) at 32 wks of age. Immunohistochemical analysis revealed correlated expression of with Stat3 transcriptional activation, proliferation and androgen receptor in tumors from castrated mice. To determine the role of IL-6R induced transcriptional activation of Stat3, non-castrated and castrated tumor bearing mice were treated with an anti-mouse IL-6R antibody (MR-16). Mice treated with MR-16 showed downregulation of phosphorylated Stat3, however, treatment failed to inhibit tumor development and cellular proliferation. However, it was discovered that therapeutic doses of MR16 treatment resulted in increased phosphorylation of Erk1/2. Our data suggests that inhibition of IL-6R-induced Stat3 activation is insufficient to suppress tumor growth; however, further studies need to be conducted to evaluate the efficacy of horizontal combination strategies targeting Stat3 and MAP kinase signaling cascades.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 3876. doi:1538-7445.AM2012-3876