bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 1898: The combination of gemcitabine/nab-paclitaxel and anti-DLL4 (demcizumab) produces synergistic growth inhibition, delays tumor recurrence and reduces tumor initiating cells in pancreatic cancer
Authors: Yen Wan-Ching , Fischer Marcus , Lewicki John , Gurney Austin , Hoey Timothy
Published: May 2015

Clinical management of pancreatic cancer is challenging and this disease remains the fourth most common cause of cancer-related death. Conventional chemotherapeutic agents, including gemcitabine, commonly used in the treatment of pancreatic cancer, have low response rates and limited effects on improving patient survival. A recent Phase III clinical trial has demonstrated that nab-paclitaxel (Abraxane, a protein-bound paclitaxel) in combination with gemcitabine significantly improved response rate and overall survival compared to patients receiving gemcitabine alone. We previously demonstrated that targeting Notch signaling by anti-DLL4 (demcizumab) inhibits tumor growth, reduces tumor initiating cell frequency and induces differentiation in patient-derived pancreatic xenograft tumors. To further explore the utility of demcizumab in the setting of pancreatic cancer, we evaluated anti-DLL4 combination with gemcitabine/ nab-paclitaxel in a panel of pancreatic xenograft models. We found that anti-DLL4 in combination with gemcitabine plus nab-paclitaxel resulted in striking tumor regression, whereas tumors treated with chemotherapeutic agents alone grew continuously. The effect of the triple combination in some tumors was quite durable and persisted after both antibody and chemotherapeutic treatments were discontinued. The significant growth inhibitory effect by the combination of anti-DLL4 with gemcitabine/nab-paclitaxel was associated with a decrease in cancer stem cell frequency and an increase in apoptosis and tumor cell differentiation. The triple combination of anti-DLL4, gemcitabine and nab-paclitaxel was generally more efficacious compared with anti-DLL4 plus gemcitabine alone. Notably, in a xenograft established from a patient that previously did not respond to demcizumab plus gemcitabine, the triple combination was highly effective. We are currently evaluating demcizumab in combination with gemcitabine plus nab-paclitaxel in a Phase 1b clinical trial in pancreatic cancer.

Citation Format: Wan-Ching Yen, Marcus Fischer, John Lewicki, Austin Gurney, Timothy Hoey. The combination of gemcitabine/nab-paclitaxel and anti-DLL4 (demcizumab) produces synergistic growth inhibition, delays tumor recurrence and reduces tumor initiating cells in pancreatic cancer. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1898. doi:10.1158/1538-7445.AM2014-1898
Abstract 1901: Detection of EML4-ALK fusion gene expression in circulating tumor cells (CTCs) captured from non-small cell lung cancer (NSCLC) patients
Authors: Park Joo Kyung , Ryu Ji Kon , Lee Se-Hoon , Kim Eun-Hye , Kim Byung-Chul
Published: May 2015

Background & Aims: Detection of unique genomic profile such as EML4-ALK rearrangement in CTCs can be directly implicated to the course of treatment in patients with NSCLC. The aims of this study were to determine 1) if CTC could reliably be identified using microfabricated porous filter platform in advanced NSCLC; 2) feasibility of RT-PCR as a useful tool in detection of EML4-ALK rearrangement from CTCs.

Method: Lung cancer cell lines with EML4-ALK rearrangement (NCI-H3122, NCI-H2228) were spiked into 5 ml of blood and were passed through the CTC platform. Twenty-five patients (19 FISH-proven ALK positive and 6 ALK negative in tissue) were prospectively enrolled in this study. Peripheral blood samples were drawn from the study patients and processed through CTC platform. Captured cells were characterized by IF staining; DAPI (nucleated cell marker), cancer cells by EpCAM and WBCs by CD45. RNA was extracted from the captured CTCs and RT-PCR was used to detect EML4-ALK fusion gene.

Results: EpCAM expression was evaluated qualitatively and quantitatively in NSCLC cell lines by FACS analysis. Surprisingly, 100% of NSCLC cells expressed EpCAM, most at very high levels (165,000 ∼ 215,274 EpCAM antigens/cell). EpCAM was uniformly expressed throughout the population. The capture yield of ALK positive lung cancer cells were varied in spiking experiments (41-59%). There were 25 stage IV NSCLC patients whose clinical situations were variable in the aspect of previous cytotoxic chemotherapies and ALK-targeted tyrosine kinase inhibitors. CTCs were detected in 41% and EML4-ALK expressions were detected by RT-PCR in 58% of initially EML4-ALK positive NSCLC patients. Sequencing of PCR products identified the expression of EML4-ALK fusion gene. The sensitivity and the specificity of RT-PCR in detection of EML4-ALK fusion gene expression from the CTCs of NSCLCs were 58% and 100%, respectively.

Conclusion

We have proved the existence of EML4-ALK positive CTCs using RT-PCR after the enrichment of CTCs from the peripheral blood of NSCLC patients. Being able to reliably capture and molecularly characterize CTC may not only allow us to characterize a patient's cancer from a simple blood draw but investigation of genomic profile from CTCs may give us insights into the genetics and biology of tumor cell dissemination with further investigation.

Citation Format: Joo Kyung Park, Ji Kon Ryu, Se-Hoon Lee, Eun-Hye Kim, Byung-Chul Kim. Detection of EML4-ALK fusion gene expression in circulating tumor cells (CTCs) captured from non-small cell lung cancer (NSCLC) patients. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1901. doi:10.1158/1538-7445.AM2014-1901
Abstract 1907: Wnt pathway antagonist OMP-54F28 (FZD8-Fc) inhibits tumor growth and reduces tumor-initiating cell frequency in patient-derived hepatocellular carcinoma and ovarian cancer xenograft models
Authors: Yeung Pete , Beviglia Lucia , Cancilla Belinda , Dee-Hoskins Cristina , Evans James W. , Fischer Marcus M. , Yen Wan-Ching , Gurney Austin , Lewicki John , Hoey Timothy , Kapoun Ann M.
Published: May 2015

The Wnt/beta-catenin pathway, which signals through the Frizzled (FZD) receptor family and several co-receptors, has long been implicated in cancer. We have developed OMP-54F28, a recombinant fusion protein consisting of the ligand-binding domain of FZD8 and a human IgG1 Fc fragment. OMP-54F28 acts as a decoy receptor in sequestering Wnts and preventing them from binding to FZD receptors and thereby inhibiting Wnt signaling. The Wnt pathway is important for stem cell self renewal, differentiation, tumorigenicity, and epithelial-mesenchymal transition (EMT). Using minimally passaged human patient-derived xenograft tumors, we demonstrate that OMP-54F28 is efficacious as a single agent and in combination with standard of care in four hepatocellular carcinoma (HCC) and two ovarian cancer models. In the HCC models, OMP-54F28 shows tumor growth inhibition (TGI) as a single agent (average of 46%, p<0.05 vs. control) and displays additive TGI in combination with Sorafenib (average of 78%, p<0.05; 48% Sorafenib alone). Also, in the ovarian cancer models, treatment with OMP-54F28 results in TGI as a single agent (average of 32% vs. control) and shows additive TGI in combination with Paclitaxel (average of 78%, p<0.05; 48% with Paclitaxel alone). We also performed in vivo serial transplantation assays and found that OMP-54F28 as a single agent and in combination with standard of care reduces tumor-initiating cell frequency in both HCC and ovarian cancer xenografts. The anti-tumor effect was associated with a decrease in cell proliferation, induction of cell differentiation, and modulation of target Wnt pathway genes. Our data demonstrate the potential therapeutic benefit of targeting Wnt signaling in HCC and ovarian cancer. OMP-54F28 is being tested in Phase 1b clinical studies in these indications.

Citation Format: Pete Yeung, Lucia Beviglia, Belinda Cancilla, Cristina Dee-Hoskins, James W. Evans, Marcus M. Fischer, Wan-Ching Yen, Austin Gurney, John Lewicki, Timothy Hoey, Ann M. Kapoun. Wnt pathway antagonist OMP-54F28 (FZD8-Fc) inhibits tumor growth and reduces tumor-initiating cell frequency in patient-derived hepatocellular carcinoma and ovarian cancer xenograft models. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1907. doi:10.1158/1538-7445.AM2014-1907
Abstract 1909: Identification and characterization of microRNA-134 as a novel receptor tyrosine kinase-regulated tumor suppressive hub in glioblastoma
Authors: Zhang Ying , Kim Jungeun , Mueller Adam C. , Dey Bijan , Yang Yanzhi , Lee Daehee , Hachmann Jan , Finderle Sanjo , Park Deric M. , Christensen James , Schiff David , Purow Benjamin , Dutta Anindya , Abounader Roger
Published: May 2015

Receptor tyrosine kinases (RTKs) are co-deregulated in a majority of glioblastoma (GBM), the most common and most deadly brain tumor. In this study, we uncovered microRNA-134 (miR-134) as a novel tumor suppressive hub that is co-regulated by multiple RTKs via MAPK and KLF4 and that acts via regulation of KRAS and STAT5B expressions. Using microRNA microarrays and qRT-PCR, we screened for microRNAs that are co-regulated by multiple RTKs in GBM. We found that miR-134 was one such microRNA that is downregulated by the activation of MET, EGFR, and PDGFR, the three most commonly deregulated RTKs in GBM. Using a combination of pharmacology, promoter analysis, transcription factor functional and rescue approaches and ChIP/qPCR, we uncovered the MAPK pathway and the transcriptional repressor KLF4 as mediators of the effects of RTKs on miR-134 repression. We then measured the expression of miR-134 and found that it was downregulated in human GBM tumors and GBM stem cells (GSCs) and that it inversely correlated with the activation levels of MET, EGFR, and PDGFR in the tumors. We demonstrated that miR-134 inhibits GBM cell and GSC proliferation, survival, and in vivo xenograft growth, as well as GSC self-renewal and stemness. We uncovered the oncogenes KRAS and STAT5B as direct targets of miR-134 with immunoblots and 3′UTR reporter assays, and showed with rescue experiments that they mediate miR-134 tumor suppressive effects. Thereafter, using a series of molecular and functional assays we established direct links and dependencies between RTKs, KLF4, miR-134, KRAS/STAT5B and malignancy in vitro and in vivo. Importantly, we also found that miR-134 induction is required for the anti-tumor effects of small molecule RTK inhibitors. Altogether, our extensive study identified miR-134 as a novel RTK-regulated tumor-suppressive hub that mediates RTK and RTK-inhibitor effects on GBM malignancy by controlling KRAS and STAT5B. These findings shed new light onto the molecular and functional interactions between RTKs and microRNAs and uncover opportunities for exploiting these interactions for therapeutic purposes.

Citation Format: Ying Zhang, Jungeun Kim, Adam C. Mueller, Bijan Dey, Yanzhi Yang, Daehee Lee, Jan Hachmann, Sanjo Finderle, Deric M. Park, James Christensen, David Schiff, Benjamin Purow, Anindya Dutta, Roger Abounader. Identification and characterization of microRNA-134 as a novel receptor tyrosine kinase-regulated tumor suppressive hub in glioblastoma. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1909. doi:10.1158/1538-7445.AM2014-1909
Abstract 1916: β3 integrin/KRAS/RalB complex drives tumor stemness and resistance to EGFR inhibition
Authors: Seguin Laetitia Jocelyne , Kato Shumei , Franovic Aleksandra , Camargo Maria Fernanda , Elliott Katrhyn , Yebra Mayra , Lesperance Jacqueline , Mielgo Ainhoa , Desgrosellier Jay , Anand Sudarshan , Weis Sara , Cheresh David
Published: May 2015

Integrin αvβ3 expression is a marker of tumor progression for a wide range of histologically distinct cancers, yet the molecular mechanism by which αvβ3 influences the growth and malignancy of cancer is poorly understood. Here, we reveal that integrin αvβ3, in the unligated state on lung, breast and pancreatic cancer cells, recruits KRAS and RalB to the plasma membrane, leading to the activation of TBK-1/c-Rel. These events are both necessary and sufficient to promote tumor initiation, anchorage-independence, self-renewal, as well as resistance to nutrient deprivation and treatment with receptor tyrosine kinase (RTK) inhibitors such as erlotinib. Genetic or pharmacological inhibition of RalB or its effectors suppress tumor initiation, self-renewal, and re-sensitizes tumors to RTK inhibition. These findings not only identify ανβ3 as a marker/driver of tumor stemness but also provide a strategy to overcome tumor resistance to RTK Inhibition.

Citation Format: Laetitia Jocelyne Seguin, Shumei Kato, Aleksandra Franovic, Maria Fernanda Camargo, Katrhyn Elliott, Mayra Yebra, Jacqueline Lesperance, Ainhoa Mielgo, Jay Desgrosellier, Sudarshan Anand, Sara Weis, David Cheresh. β3 integrin/KRAS/RalB complex drives tumor stemness and resistance to EGFR inhibition. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1916. doi:10.1158/1538-7445.AM2014-1916
Abstract 1919: Profiling of cancer cell lines demonstrates a dynamic relationship between epithelial, mesenchymal and cancer stem states
Authors: Hernandez James R. , Mooney Steven M. , Shiraishi Takumi , Verdone James E. , Harberg Calvin A. , Vindivich Donald , Pienta Kenneth J.
Published: May 2015

Our previous work has demonstrated that exposure of M2 - Tumor Associated Macrophages M2-TAMs) to epithelial cancer cells can induce an Epithelial to Mesenchymal Transition (EMT). The resulting mesenchymal cancer cells exhibit a more aggressive phenotype, which places patients at a higher risk of relapse and death. Although most patients are cured by radical prostatectomy or radiation, it has been demonstrated that the majority of patients have disseminated tumor cells in their bone marrow at the time of primary treatment and approximately 10-15% of these men will eventually suffer a relapse after a period of dormancy. Further characterization of these disseminated cells both at the time of primary treatment and over time, is needed. It is unclear if these cells, especially those destined to eventually proliferate, are “mesenchymal”, “epithelial”, or “cancer stem” cells (CSCs). In this work, we investigate the CSC molecular and gene expression profile across multiple cancer cell lines and cell phenotypes. In part, this was done by utilizing various culturing conditions, such as 3D growth in stem cell media in order to generate sphere-like cultures known as tumorspheres. Flow cytometric analysis was performed based on ALDH, CD44 variant and CD133 expression. This was followed by gene expression analysis and characterization of the resulting tumorspheres and standard 2D cultures. The results demonstrate that there may be a level of plasticity that allows these cancer cells to alter gene expression and shift towards a CSC state and/or that there is a common CSC progenitor that exists within the population which can give rise to both epithelial and mesenchymal cell types. Therefore, furthering our understanding of the dynamic relationship between CSCs, EMT, and the converse mesenchymal to epithelial transition, is critical in developing novel therapeutics and prognostic tools in the field of cancer medicine.

Citation Format: James R. Hernandez, Steven M. Mooney, Takumi Shiraishi, James E. Verdone, Calvin A. Harberg, Donald Vindivich, Kenneth J. Pienta. Profiling of cancer cell lines demonstrates a dynamic relationship between epithelial, mesenchymal and cancer stem states. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1919. doi:10.1158/1538-7445.AM2014-1919
Abstract 1925: CK2 phosphorylates and inhibits tumor suppressor TAp73 function to promote cancer stem cell gene expression and phenotype in head and neck cancer
Authors: Lu Hai , Yan Carol H. , Bian Yansong , Chen Zhong , Waes Carter Van
Published: May 2015

Cancer development, cell survival, and therapeutic resistance have recently been linked to a small sub-population of cells expressing stem cell genes, and capable of reproducing the cancer cell population, called cancer stem cells (CSC). CK2 (formerly casein kinase II) has emerged as a key signal serine/threonine kinase that modulates diverse signal cascades that regulate cell fate and growth. We previously showed that CK2 is aberrantly expressed and activated in head and neck squamous cell carcinomas (HNSCC). Concomitant inactivation of tumor suppressor TAp73, along with mutation of related family member TP53, is also often observed, but the relationship between CK2, TAp73 inactivation, and CSC is unknown. Here, we observed that classical stem cell genes NANOG, SOX2, and OCT4, are overexpressed in HNSCC with inactivated TAp73 and mtTP53. Inhibition of CK2 by pharmacologic inhibitors or siRNA increased TAp73 mRNA and protein expression, while inhibiting CSC gene expression and the SP. Conversely, knockdown of TAp73 increased CSC gene expression and the SP. Bioinformatic analysis identified a single predicted CK2 threonine phosphorylation site (T27) within the N-terminal transactivation domain of TAp73. Nuclear CK2 and TAp73 interaction, confirmed by co-immunoprecipitation, was attenuated by CK2 inhibitor, or a T27A point-mutation of the predicted CK2 threonine phospho-acceptor site of TAp73. Furthermore, T27A mutation attenuated TAp73 phosphorylation, while enhancing its function in repressing CSC gene expression, and SP cells. Novel CK2 inhibitor CX-4945 inhibited CSC related SP cells, clonogenic survival, and spheroid formation, identifying CK2 modulation of tumor suppressor TAp73 as a potential target for inhibition of CSCs. Our study reveals a novel regulatory mechanism whereby aberrant CK2-mediated inactivation of TAp73 tumor suppressor function promotes key CSC genes and phenotype.

Supported by NIDCD intramural project ZIA-DC-00073

Citation Format: Hai Lu, Carol H. Yan, Yansong Bian, Zhong Chen, Carter Van Waes. CK2 phosphorylates and inhibits tumor suppressor TAp73 function to promote cancer stem cell gene expression and phenotype in head and neck cancer. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1925. doi:10.1158/1538-7445.AM2014-1925
Abstract 193: Adipocytes, obesity and the multiple myeloma microenvironment
Authors: Henry Gervaise H. , Watson Nicholas J. , O'Neill Rebecca C. , Tabib Tracy , Bullwinkle Erika M. , DeCicco-Skinner Kathleen L.
Published: May 2015

Multiple myeloma (MM), a hematological malignancy characterized by monoclonal plasma cells in the bone marrow, affects nearly 23,000 Americans per year. Obesity contributes to the development and progression of multiple myeloma, yet the relationship between MM cells and adipocytes found in the tumor microenvironment has not been fully elucidated. To examine how adipocytes contribute to the growth and progression of MM, we co-cultured human myeloma cell lines with primary human adipocytes isolated from lipoaspirates. We found that MM cells directly co-cultured with adipocytes or exposed to their conditioned media had increased viability, angiogenic potential, invasion, colony formation, and production of inflammatory cytokines, when compared to MM cells alone. Moreover, adipocytes from obese individuals (BMI > 30) further compounded this. Thus, we demonstrate an important role for adipocytes in promoting myeloma pathologies.

Citation Format: Gervaise H. Henry, Nicholas J. Watson, Rebecca C. O'Neill, Tracy Tabib, Erika M. Bullwinkle, Kathleen L. DeCicco-Skinner. Adipocytes, obesity and the multiple myeloma microenvironment. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 193. doi:10.1158/1538-7445.AM2014-193
Abstract 1938: Inhibition of both physiological and aberrant Wnt/β-catenin signaling activities associated with stemness in nasopharyngeal carcinoma
Authors: Cheng Yue , Phoon Yee Peng , Lung Maria L.
Published: May 2015

We previously demonstrated that basic or physiological levels of β-catenin signaling and tissue context play decisional roles in the regulation of self-renewal networks in nasopharyngeal carcinoma (NPC) HONE1 cells. Introduction of physiological levels of β-catenin signaling in HONE1 hybrid cells plays a central role in the control of other pathway activities, such as TGF-β, Activin, and pluripotency maintenance (LIFR and IL6ST), during the stemness transition process. These results revealed novel regulatory relationships among Wnt signaling, stemness, epithelial-mesenchymal transition (EMT), tumor suppressive pathways and expression of common cancer stem cell surface markers, such as CD44 and CD133, in human tumor cells. In current studies, we found that several NPC cell lines, including CNE1, HK1, HNE1, SUNE1, and C666-1, have aberrant and significant up-regulation of β-catenin expression, when compared to HONE1 cells that have low levels endogenous β-catenin expression. In these NPC cells with aberrant β-catenin signaling activities, the Wnt pathway (Axin2, APC, TCF1 and TCF3), stemness factors (Nanog, and Oct4) and pluripotency markers (IFITM1 and GRB7) are strongly overexpressed, compared to HONE1 cells. Our findings suggest that aberrant Wnt/β-catenin signaling activities may play a prominent role in promoting tumor progression in NPC cells. To further verify the role of aberrant β-catenin signaling in NPC, we utilize shRNA to knock down β-catenin expression in these cells, including CNE1 and HK1. As found in HONE1 hybrids, the diminished expression of core stem cell factors (Nanog, Oct4, Klf4, and Sox2) is also detected in both CNE1 and HK1 cell lines. Concomitantly, the gene expression of EMT markers (E-cadherin and Zeb1) is also inhibited when β-catenin is knocked down by shRNA β-catenin infection. These preliminary results suggest that β-catenin signaling plays a dominant role in regulating both physiological and aberrant Wnt/β-catenin signaling activities as well as EMT events in NPC development.

Citation Format: Yue Cheng, Yee Peng Phoon, Maria L. Lung. Inhibition of both physiological and aberrant Wnt/β-catenin signaling activities associated with stemness in nasopharyngeal carcinoma. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1938. doi:10.1158/1538-7445.AM2014-1938
Abstract 194: E-selectin mediates targeted delivery of mesenchymal stem cells to tumor
Authors: Yang Cuixia , Li Danjuan , Wang Bo , Velazquez Omaida C. , Liu Zhao-Jun
Published: May 2015

Objectives. Tumor tissue produces abundant stromal cell-derived factor-1α (SDF-1α/CXCL12) that promotes recruitment of circulating stem/progenitor cells. We have recently found that SDF-1α induces elevated expression of CD162 and CD44, both are E-selectin ligands, on luminal endothelial cells lining capillaries. We thus postulate that highly expressed E-selectin ligands on tumor endothelium can serve as docking molecules to mediate specific homing of E-selectin-expressing circulating stem cells to tumor tissues. Here, we tested the role of E-selectin in mediating and facilitating homing of mesenchymal stem cells (MSC), which are modified to overexpress E-selectin, to SDF-1α−rich melanoma tissue.

Methods. MSC from C57 BL6 and E-selectin-/- mice were enriched by culturing bone marrow cells in MesenCultTM medium. MSC were genetically labeled with luciferase (Luc2) or GFP in vitro. MSC from C57 BL6 mice were engineered to stably overexpress E-selectin (E-selectin+). Human melanoma cells were engineered to overexpress SDF-1α. 2 x 10^6 SDF-1α+/melanoma cells were pre-engrafted into NSG mice via tail-vein or subcu to form lung metastatic foci or skin melanoma, respectively. After 7-10 days, 1 x 10^6 E-selectin+ or E-selectin-/- MSC were injected into tumor-bearing mice through tail-vein or subcu, respectively. Homing of injected MSC to melanoma was assessed at various time points by IVIS (for Luc2+/MSC) and flow cytometry (for GFP+/MSC), respectively.

Results. There were significantly increased numbers of engineered E-selectin-overexpressing MSC homing to melanoma tissues via systemic and local approaches, compared to control MSC or E-selectin-/-/MSC (p<0.05).

Conclusions. E-selectin is an effective adhesion molecule in mediating tumor selective homing of MSC. Our study provides a useful method for targeted delivery of cells to tumor and may have therapeutic potential for developing stem cell-based cancer treatment.

Citation Format: Cuixia Yang, Danjuan Li, Bo Wang, Omaida C. Velazquez, Zhao-Jun Liu. E-selectin mediates targeted delivery of mesenchymal stem cells to tumor. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 194. doi:10.1158/1538-7445.AM2014-194
Abstract 1941: GSK3 signaling is critical to glioma stem cell growth and survival
Authors: Alvarez Angel , Ugolkov Andrey , Gaisina Irina , Kozikowski Alan P. , Joshi Kaushal , Kim Sunghak , Nakano Ichiro , Raizer Jeffrey J. , Mazar Andrew P. , Hu Bo , Cheng Shi-Yuan
Published: May 2015

GSK3 is an attractive therapeutic target in cancer, known for its role in regulating proliferation, differentiation, metabolism, and apoptosis. Previous studies demonstrate the effectiveness of GSK3 inhibition on established glioma cell lines and patient-derived glioma stem cell lines in vitro and in vivo. In glioma cell lines, GSK3 inhibition induces apoptosis through c-MYC activation, mitochondrial destabilization, and reduction of NF-κB activity. We have characterized a novel set of GSK3 inhibitors for their ability to inhibit glycogen synthase phosphorylation, reduce levels of XIAP, and induce cell death in cancer cells. However, it is uncertain if this mechanism is functional with respect to cancer stem cells and glioma tumor subtype. The need to investigate the mechanistic effects of GSK3 in cancer stem cells is important given their malignancy, innate resistance to therapy, and tumorigenicity. Moreover, the intracellular signaling and transcription networks may differ in glioma stem cells, particularly among cells with different subtypes. We have recently demonstrated that cancer stem cells isolated from glioma patients can be segregated into either a proneural or mesenchymal subtype based on their gene expression pattern. The oncogenic activity of genes like c-MYC in glioma stem cells and differences between glioma stem cell subtypes, such as NF-κB activation, raises questions as to whether GSK3 inhibition will be effective against both subtypes and if their effects utilize distinct mechanisms of inhibition. In this study, we examine the effects of two established and two novel GSK3 inhibitors on glioma stem cells with respect to tumor subtype and investigate their mechanisms of action. Our in vitro data shows that GSK3 inhibition significantly reduces growth and causes cell death in both proneural and mesenchymal glioma stem cells. Using a glioma stem cell xenograft model, we test the effectiveness of GSK3 inhibition as a single agent and in conjunction with clinically-approved chemotherapeutic agents. The characterization of cancer stem cell inhibitors and their effectiveness in different tumor subtypes has significant clinical implications. Our work supports the therapeutic potential of novel GSK3 inhibitors for the treatment of malignant gliomas.

Note: This abstract was not presented at the meeting.

Citation Format: Angel Alvarez, Andrey Ugolkov, Irina Gaisina, Alan P. Kozikowski, Kaushal Joshi, Sunghak Kim, Ichiro Nakano, Jeffrey J. Raizer, Andrew P. Mazar, Bo Hu, Shi-Yuan Cheng. GSK3 signaling is critical to glioma stem cell growth and survival. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1941. doi:10.1158/1538-7445.AM2014-1941
Abstract 1942: Lgl1 loss promotes stemness and invasion in EGFRvIII-driven gliomas
Authors: Gomez-Lopez Sandra , Lerner Robin G. , Petritsch Claudia
Published: May 2015

Stem and progenitor cells may divide asymmetrically to self-renew and produce differentiating progeny in a single division. Usually, during an asymmetric cell division (ACD), determinants of self-renewal and differentiation segregate to opposite daughter cells during mitosis and thereby specify distinct cell fates.

Disruption of ACD is seen in many cancers with a stem or progenitor cell component, including malignant gliomas (Sugiarto et al., 2011, Cancer Cell 20:328-40). Yet, it is not clear whether this is a contributing factor or a consequence of neoplastic transformation. Lethal giant larvae 1 (Lgl1), a gene that was initially identified as a tumor suppressor in Drosophila, has been implicated in the asymmetric localization of cell fate determinants in neural progenitor cells (Klezovitch et al., 2004, Genes Dev 18:559-571). Here, we investigated the effects of Lgl1 depletion on distinct hallmarks of glioma.

In murine neural progenitor cells carrying conditional null alleles of Lgl1 (Klezovitch et al., 2004, Genes Dev 18:559-571), depletion of Lgl1 resulted in reduced rates of ACD, increased expression of progenitor markers and impaired differentiation. In an orthotopic model of glioma, driven by expression of EGFRvIII, a frequent and constitutively active mutant form of epidermal growth factor receptor (EGFR), Lgl1 inactivation led to increased tumor invasiveness.

Our data suggest that disruption of ACD in glioma precursor cells promotes maintenance of progenitor features and hampers differentiation. At later stages of gliomagenesis, loss of ACD and cell polarity controls may contribute to tumor invasiveness.

Citation Format: Sandra Gomez-Lopez, Robin G. Lerner, Claudia Petritsch. Lgl1 loss promotes stemness and invasion in EGFRvIII-driven gliomas. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1942. doi:10.1158/1538-7445.AM2014-1942
Abstract 1966: A unique cross-talk between HER2 and sonic hedgehog signaling promotes anoikis resistance in breast cancer cells
Authors: Gupta Parul , Srivastava Sanjay K.
Published: May 2015

Metastatic cancer cells possess a unique capacity to survive without appropriate signaling from the extracellular matrix (ECM). The epithelial cells surrounded by proper ECM within tissues are designed to grow and differentiate whereas epithelial cells lacking suitable EMC are destined to anoikis, a form of apoptosis. The metastatic cancer cells resist anoikis to survive under the absence of ECM. Current study identifies a novel interplay between HER2 and sonic hedgehog signaling in promoting anoikis resistance. MDA-MB-231 cells exhibited an up-regulation of HER2 expression in cells cultured under anchorage- independent conditions as compared to adherent cells. Similar phenomenon was also observed in 4T-1 cells. The survival of MDA-MB-231 cells with stable HER2 overexpression (HH) was significantly enhanced when cultured under anchorage-independent conditions. However, the enhanced survival of MDA-MB-231 (HH) was reduced when HER2 was silenced using shRNA. These observations indicate the obligatory role of HER2 in anoikis resistance. Furthermore cells grown under anchorage-independent conditions induced the expression of sonic hedgehog (SHH). Increase in SHH was accompanied with enhanced expressions of PTCH2 and GLI2, the receptor and subsequent transcription factors of the sonic hedgehog signaling. Our results further showed that the induction of SHH was significantly higher in MDA-MB-231 (HH) cells relative to parent cells when cultured under anchorage-independent conditions, suggesting a correlation between HER2 and SHH signaling. Treatment of MDA-MB-231 and 4T-1 cells with cyclopamine (SHH signaling inhibitor) reduced the survival of cells under anchorage-independent conditions. Interestingly, cyclopamine treatment also inhibited the induction of HER2 during anchorage-independent culture conditions. Taken together, our study suggests a SHH-mediated induction of HER2 to promote anoikis resistance in breast cancer cells. Further mechanistic and in vivo studies are under progress. [Supported in part by R01 grant CA129038 (to S.K.S) awarded by the National Cancer Institute].

Citation Format: Parul Gupta, Sanjay K. Srivastava. A unique cross-talk between HER2 and sonic hedgehog signaling promotes anoikis resistance in breast cancer cells. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1966. doi:10.1158/1538-7445.AM2014-1966
Abstract 1970: Co-culture of 3D tumor spheroids with fibroblasts as an in vitro model for drug resistance study
Authors: Kim Sun-Ah , Kuh Hyo-Jeong
Published: May 2015

Purpose. Chemotherapeutic failure of human solid tumor is attributed to tumor microenvironmental (TME) factors associated with drug resistance. Three dimensional (3D) tumor spheroid (TS) model is known to be in vivo mimic and has demonstrated its clinical relevancy. Fibroblasts in TME have been shown to play a significant role in drug resistance. The present study was to develop and characterize a co-culture of 3D TS with fibroblasts for human colorectal tumor model.

Methods. TS of human colorectal cancer cells (HT-29) was prepared by using liquid overlay method and co-cultured in collagen-coated 24-well plates with colon fibroblasts (CCD-18co) grown in Transwell® inserts. Differentail expression of extracellular matrix (ECM), growth signaling molecules, and microRNAs was analyzed using IHC, ELISA, western blot and qRT-PCR. For miRNA transfection study, changes in motility and drug sensitivity were measured by wound healing assays and APH or MTS assay, respectively.

Results. Significant resistance to 5-FU was shown in TS either with or without fibroblasts compared to monolayers. Compared to single culture of TS, co-culture with fibroblast showed 1.3-fold increased outgrowth on collagen gel, indicating increased motility. Cell-to-cell adhesion structures, expression of ECM and active form TGFβ1 were higher in TS-fibroblast co-culture. Expression of several growth- and TME-related factors, such as fibronectin, EGFR, β-catenin and CTGF, was higher in fibroblast co-culture up to the level of HT-29 xenograft tissues. Among miRNAs showing differential expressions, miR-96 showed down-regulation in TS. HT-29 cells transfected with miR-96 showed increase in cell motility, proliferation, and sensitivity to 5-FU, suggesting its potential role in regulation of genes associated with 5-FU resistance.

Conclusions. Co-culture of 3D TS-fibroblasts was successfully established and demonstrated in vivo mimic characteristics with respect to presence of adhesion microstructures, expression of ECM and growth signaling molecules, and resistance to 5-FU. MiR-96 showed its potential role in 3D drug resistance which warrants further studies.

Citation Format: Sun-Ah Kim, Hyo-Jeong Kuh. Co-culture of 3D tumor spheroids with fibroblasts as an in vitro model for drug resistance study. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1970. doi:10.1158/1538-7445.AM2014-1970
Abstract 1975: Real-time FUCCI imaging demonstrates targeting dormant cancer cells
Authors: Yano Shuya , Zhao Ming , Tazawa Hiroshi , Hoffman Robert M. , Fujiwara Toshiyoshi
Published: May 2015

Screening for agents that specifically kill quiescent cancer cells has not been possible due to the inability to readily identify these cells. Using cancer cells expressing a fluorescent ubiquitination-based cell cycle indicator (FUCCI), we describe here an approach to screening for agents against dormant tumor spheres consisting of cancer stem-like cells expressing CD133. In the FUCCI system, cycling cells have green fluorescent nuclei and quiescent cells contain nuclei which fluoresce red. FUCCI-expressing cancer cells in tumor spheres had predominantly red nuclei after more than 7 days without cell division. Conventional anticancer agents did not kill these quiescent cells. In contrast, the genetically-engineered oncolytic adenovirus OBP301 and Salmonella typhimurium A1-R induced quiescent cancer cells to cycle and become sensitive to DNA-damaging chemotherapy. This imaging technology provides a novel platform for visualizing trafficking candidate therapeutic agents that could decoy dormant cancer cells to cycle and become chemosensitive.

Citation Format: Shuya Yano, Ming Zhao, Hiroshi Tazawa, Robert M. Hoffman, Toshiyoshi Fujiwara. Real-time FUCCI imaging demonstrates targeting dormant cancer cells. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1975. doi:10.1158/1538-7445.AM2014-1975
Abstract 1982: Invading cancer cells are mostly in G0/G1 and resist chemotherapy demonstrated by real-time FUCCI imaging of cell-cycle kinetics in Gelfoam® histoculture
Authors: Yano Shuya , Miwa Shinji , Mii Sumiyuki , Hiroshima Yukihiko , Uehara Fuminari , Kishimoto Hiroyuki , Tazawa Hiroshi , Zhao Ming , Bouvet Michael , Fujiwara Toshiyoshi , Hoffman Robert M.
Published: May 2015

Invasive cancer cells are a critical target for chemotherapy in order to prevent metastasis. In the present report, we demonstrate real-time visualization of cell-cycle kinetics of invading cancer in three-dimensional (3D) Gelfoam® histoculture. A fluorescence ubiquitination cell cycle indicator (FUCCI) was used whereby G1/G0 cells express a red fluorescent protein and S/G2/M cells express a green fluorescent protein. With FUCCI imaging, we observed that cancer cells in G0/G1 phase in Gelfoam® histoculture migrated more rapidly and further than the cancer cells in S/G2/M phase. Cancer cells ceased migrating when they entered S/G2/M phases and restarted migrating after division and re-entry into G1/G0. Migrating cancer cells also were resistant to chemotherapy since they were preponderantly in G1/G2 and cytotoxic chemotherapy targets cells in S/G2/M phase. The results of the present report suggest that novel therapy targeting G1/G2 cancer cells is necessary to prevent metastasis.

Citation Format: Shuya Yano, Shinji Miwa, Sumiyuki Mii, Yukihiko Hiroshima, Fuminari Uehara, Hiroyuki Kishimoto, Hiroshi Tazawa, Ming Zhao, Michael Bouvet, Toshiyoshi Fujiwara, Robert M. Hoffman. Invading cancer cells are mostly in G0/G1 and resist chemotherapy demonstrated by real-time FUCCI imaging of cell-cycle kinetics in Gelfoam® histoculture. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1982. doi:10.1158/1538-7445.AM2014-1982
Abstract 1983: Real-time imaging of exosomes dynamic of cross-talking and cell trafficking in 3D Gelfoam® histoculture
Authors: Yamamoto Mako , Miwa Shinji , Hiroshima Yukihiko , Yano Shuya , Uehara Fuminari , Matsumoto Yasunori , Suetsugu Atsushi , Homma Kimi , Hoffman Robert M.
Published: May 2015

Exosomes are small membrane vesicles (30-100 nm) released by many types of cells during normal physiological processes and are thought to play an important role in cell-to-cell communication to promote tumor metastasis. Exosomes contain diffusible factors, such as cytokines, growth factors and extracellular matrix molecules and also mediate local and systemic cell communication through the horizontal transfer of information, such as mRNAs, microRNAs and proteins. However, the exosome dynamics and trafficking between cancer cells and tumor stromal cells in a metastatic niche are still unclear. In this study, in order to image the movement of cancer cell-derived exosomes, we developed a confocal time lapse imaging system to use green fluorescent protein (GFP)-tagged CD63, which is a general marker of exosomes, expressed in breast cancer cells cultured on 3-dimentional Gelfoam® histoculture. We demonstrated that 3D Gelfoam® culture enabled imaging of structural cell-to-cell contact between neighboring cells and exosome behavior in real-time. This system makes it possible to monitor real-time exosome dynamics and cross-talking between cancer cells and other cells and to identify the mechanism of exosome release and uptake such as in a metastatic niche.

Citation Format: Mako Yamamoto, Shinji Miwa, Yukihiko Hiroshima, Shuya Yano, Fuminari Uehara, Yasunori Matsumoto, Atsushi Suetsugu, Kimi Homma, Robert M. Hoffman. Real-time imaging of exosomes dynamic of cross-talking and cell trafficking in 3D Gelfoam® histoculture. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1983. doi:10.1158/1538-7445.AM2014-1983
Abstract 2002: A novel candidate metastasis-associated protein, MAP40, differentially expressed in highly metastatic breast cancer cells reveals an essential role in tumor metastasis
Authors: Kim Mijin , Kim Seong-Jin
Published: May 2015

Metastasis is the underlying cause of death in the majority of patients with breast cancer who succumb to their disease, but the fundamental mechanisms remain poorly understood. Here we have found a novel candidate of metastasis-associated protein, MAP40, which is highly expressed membrane protein in the metastatic breast cancer cell lines. Using the public microarray datasets, we also found that MAP40 is significantly increased in the basal type of breast tumors compared to the luminal subtype. We undertook the lentivirus-based system to functionally silence MAP40 gene in basal-like breast cancer cell lines. Knockdown of MAP40 results in a significant reduction of cell migration and invasiveness as well as suppression of anchorage-independent growth in basal-like breast cancer cells. Additionally, depletion of MAP40 induces E-cadherin expression, while integrin β1 protein level is suppressed. Together with results from studies in animal models suggest that MAP40 may promote tumor formation and direct metastasis of breast cancer in vivo. Ongoing studies to find interacting partners and downstream genes will allow us to further understand its mechanism in metastasis.

This work was supported by a National Research Foundation grant of Korea (2009-0081756) funded by the Korea government.

Citation Format: Mijin Kim, Seong-Jin Kim. A novel candidate metastasis-associated protein, MAP40, differentially expressed in highly metastatic breast cancer cells reveals an essential role in tumor metastasis. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 2002. doi:10.1158/1538-7445.AM2014-2002
Abstract 2007: Hypoxia induced TGF-β regulates Semaphorin7A to promote a pro-tumorigenic mesenchymal phenotype in mammary cells
Authors: Garcia-Areas Ramon A. , Libreros Stephania , Amat Samantha , Castro-Silva Camila , Schilling Kathy , Iragavarapu-Charyulu Vijaya
Published: May 2015

The study of breast cancer relies heavily upon the identification of tumor-associated proteins that are involved with tumor growth and development. Our lab has discovered that mammary tumor cells express high levels of a novel protein known as Semaphorin7A (SEMA7A). After analyzing breast tissue samples collected at Boca Raton Regional Hospital, we have found that normal human mammary epithelial cells express negligible mRNA levels of SEMA7A, while the malignant mammary tumor cells express elevated levels of SEMA7A. Additionally, our laboratory has established a murine model of mammary cell lines that parallels our human findings. Currently, we have correlated high levels of SEMA7A with increasing tumor malignancy and metastasis. However, it is still unknown what factors could induce the production of SEMA7A in mammary tumors. Recent studies have proven that the expression and induction of SEMA7A in normal endothelial cells is regulated under a hypoxic-response element in the promoter of its gene. Although hypoxia is an established tumorigenic factor, it is unknown if the increased hypoxic conditions in breast tumors could induce SEMA7A. In this study we have investigated if exposing mammary cells to hypoxia induces the expression of pro-tumorgenic SEMA7A. Our results show that SEMA7A is up-regulated in 4T07 and 4T1 mammary tumor cells after hypoxic exposure via TGF-β activation of the PI3/AKT pathway. Furthermore, we have found that shRNA silencing of the SEMA7A in 4T1 mammary cells attenuates the activation of pro-angiogenic and mesenchymal genes even after hypoxic stimuli. In vivo, these cells show a reduced proliferation and metastatic potential. We therefore postulate an exciting new role for SEMA7A as a TGF-β effector that promotes tumorigenesis during breast cancer progression.

Citation Format: Ramon A. Garcia-Areas, Stephania Libreros, Samantha Amat, Camila Castro-Silva, Kathy Schilling, Vijaya Iragavarapu-Charyulu. Hypoxia induced TGF-β regulates Semaphorin7A to promote a pro-tumorigenic mesenchymal phenotype in mammary cells. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 2007. doi:10.1158/1538-7445.AM2014-2007