bluuebunny/crossref_metadata_2025_split huggingface dataset:
Abstract 2498: Tumorspheres cultured from circulating epithelial tumor cells (CETCs) overexpress stem cell markers in patients with solid cancers
Authors: Pachmann Katharina , Pizon Monika , Schott Dorothea , Pachmann Ulrich 
Published: July 2016

Abstract
Background: Solid malignancies continuously shed tumor cells which may enter the circulation, spread to other tissues and initiate metastases, but it is assumed that only a small subpopulation among CETCs is capable of metastasis formation, the subpopulation of CETCs capable of forming tumorspheres in vitro and carrying stem cells properties. The aim of this study was to characterize the pattern of expression of the tumorspheres as compared to CETCs. Methods: Blood samples were obtained from patients diagnosed with solid tumors. CETCs were enumerated with the maintrac method and subsequently cultivated in epithelial stem cell-selective medium. Immunofluorescence and qRT-PCR were performed to examine the metastatic ability of tumorspheres in vitro. Results: Analysis of surface markers in non-adherent tumorspheres forming from CETCs under stem cell- selective conditions after a period of 14 days showed typical phenotype for cancer stem cells depending on type of cancer. Furthermore, spheres had high enzymatic activity for ALDH 1. Array qRT-PCR analysis revealed that putative stem cell markers, such as Oct4, Sox2, Nanog, EpCAM, ALDH1 and CD133 are overexpressed in relation to house-keeping genes RPL13a and GAPDH in tumor spheres in contrast to the significantly lower expression level of these stem cell markers in individually isolated CETCs. High expression level of pluripotency genes in tumorspheres was associated with aggressive tumor behaviour in terms of tumor progression and type of cancer. Conclusion: Here we show that stem cell markers are overexpressed in tumorspheres as compared to CETCs. Obviously only a small population of CETCs can be grown into spheres which possess stem cell properties and most probably are responsible for recurrence and treatment failure. Precise characterization of CETCs and tumorspheres on the single cell and sphere level will contribute to a better understanding of metastasis formation and lead to development of cancer stem cell based cancer therapy.
Citation Format: Katharina Pachmann, Monika Pizon, Dorothea Schott, Ulrich Pachmann. Tumorspheres cultured from circulating epithelial tumor cells (CETCs) overexpress stem cell markers in patients with solid cancers. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 2498.
Abstract 2505: GNA13 induction of stemness and resistance to chemotherapy in breast and head and neck cancers
Authors: Leong Hui Sun , Rasheed Suhail Ahmed Kabber , Lakshmanan Manikandan , Raju Anandh Kumar , Tergaonkar Vinay , Tan Daniel shao-Weng , Casey Patrick , Iyer N.Gopalakrishna 
Published: July 2016

Abstract
Despite advancement in cancer therapy, the ability of cancer cells to evade therapy often leads to tumor recurrence and distant metastasis, and ultimately to the death of the patient. Increasing evidence shows that these properties of recurrence can be attributed to a small population of cells within the tumor termed cancer stem cells (CSCs). Understanding the mechanisms that support the growth of CSCs could provide new tools to target these cells and improve therapeutic outcomes. G12 proteins, comprised of Gα12 (GNA12) and Gα13 (GNA13) are mediators of G protein coupled receptor (GPCR) signaling. These proteins are highly expressed in several cancers, and blocking their signaling can significantly inhibit cancer cell invasion and metastasis. Recently, we have shown that loss of GNA13 alone can suppress invasion of breast and prostate cancer cells. Moreover, we have recently obtained evidence that enhanced expression of GNA13 is capable of inducing a stem cell phenotype in cancer cells. Specifically, enforced expression of GNA13 in cancer cells containing low levels of GNA13 protein significantly induced CSC population as shown by increased aldehyde dehydrogenase (ALDH1) activity, increased CD44+/CD24− cells, and enhancement of tumor sphere formation. In contrast, in cancer cells that express high levels of GNA13, knockdown of GNA13 suppressed ALDH1 activity, the CD44+/CD24− cell population, and the formation of spheres. Using reporter assays we have identified that GNA13 induced CSC phenotype most probably via activating Jun Kinase - AP1 signaling pathway and blocking this pathway could significantly inhibit CSC phenotype induced by GNA13. Most importantly we have identified that GNA13 expressing cells are resistant to most commonly used chemotherapeutic agents and ionizing radiations. Blocking GNA13 using shRNAs sensitized these cells to both chemo- and radiotherapy significantly. We therefore hypothesize that GNA13 plays a pivotal role in the induction of CSCs and drug resistance, and the suppression of GNA13 activity may provide therapeutic advantage to cancer therapy.
Citation Format: Hui Sun Leong, Suhail Ahmed Kabber Rasheed, Manikandan Lakshmanan, Anandh Kumar Raju, Vinay Tergaonkar, Daniel shao-Weng Tan, Patrick Casey, N.Gopalakrishna Iyer. GNA13 induction of stemness and resistance to chemotherapy in breast and head and neck cancers. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 2505.
Abstract 2514: Second generation HDAC inhibitor, Quisinostat reinstates RD3 in neuroblastoma CSCs and promotes stem cell differentiation
Authors: SOMASUNDARAM DINESH BABU , Aravindan Natarajan 
Published: July 2016

Abstract
Recently, we characterized the adaptive stemness and extreme plasticity of neuroblastoma (NB) cancer stem cells (CSCs). Further, new to science, we defined the loss of retinal degeneration protein 3 (RD3) in high-risk NB and identified its novel tumor evolution stabilization function. Moreover our studies identified definitive contribution of HDACs in the evolution of progressive NB. Herein, we investigated the potential of pyrimidyl-hydroxamic acid HDAC inhibitor, Quisinostat in restoring RD3 and NB-CSCs differentiation. Well characterized CD133+-CD34+ human NB CSCs exposed to increasing concentrations (2.5, 5, 10, 100, 200nM, 1, 2, 4, 8μM) of quisinostat were examined for inhibition of HDACs (HDACs 1-11, QPCR analysis), transcriptional (QPCR) and translational (immunoblotting) restoration of RD3, CSCs cell viability (automated trypan exclusion assay) differentiation (real-time live cell imaging) and formation of organized tumorospheres (tumorosphere formation assay). Quisinostat inflicted complete inhibition of NB-CSCs cell viability at 100nM concentration and beyond. QPCR analysis revealed a dose-dependent inhibition of HDACs in NB CSCs with quisinostat. We observed a significant transcriptional/translational restoration of RD3 selectively at 100nM and above of quisinostat treatment. Live-cell imaging demonstrated a dose-dependent -loss of stemness behavior and -increased differentiation of NB CSCs with quisinostat treatment. Tumorosphere formation assay demonstrated complete inhibition of organized tumorospheres at/after 100nM treatment. These results imply that Quisinostat restores RD3 and promotes NB-CSCs differentiation. More importantly, selective dose-dependent specificity of HDAC inhibition by Quisinostatnt and, restoration of RD3 and regulation of stemness physiognomies at/above 100nM concentrations identifies that HDAC 7 could serve as a critical player in this setting. Taken together, these results for the first time identify the potential of quisinostat in the regulation of NB evolution and with further studies may serve as a potential drug deliverable in the treatment and cure of high-risk NB.
Acknowledgements: Stephenson Cancer Center - Experimental Therapeutics Program, NIH COBRE 1P20GM103639-01.
Citation Format: DINESH BABU SOMASUNDARAM, Natarajan Aravindan. Second generation HDAC inhibitor, Quisinostat reinstates RD3 in neuroblastoma CSCs and promotes stem cell differentiation. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 2514.
Abstract 2520: IRS-1/LC3 nuclear structures and glioblastoma drug resistance
Authors: Lassak Adam , Wyczechowska Dorota , Wilk Anna , Zapata Adriana , Dean Mathew , DelValle Luis , Sarkaria Jann N. , Ochoas Augusto , Peruzzi Francesca , Reiss Krzysztof 
Published: July 2016

Abstract
Drug resistance and frequent tumor relapses are the major obstacles in glioblastoma therapy, and recurrent tumors are practically incurable. We previously reported that insulin receptor substrate 1 (IRS-1), which is a typical signaling molecule for insulin and insulin-like growth factor 1 receptors, can translocate to nucleus, and that nuclear IRS-1 (nIRS-1) was found in different tumor cells, including glioblastomas. To unravel its function, we employed glioblastoma cell culture, animal models, and clinical samples. Using confocal imaging, molecular cloning, subcellular fractionation, mass spectrometry, gene expression analysis, and different approaches to verify protein-protein interactions, we demonstrate for the first time that nIRS-1 can form complex nuclear structures in a restricted number of cancer cells in glioblastoma biopsies and in intracranial glioblastoma xenografts. We also demonstrated the formation of highly organized ring-like structures in several cell lines, following ectopic expression of IRS-1 cloned in frame with nuclear localization signal (NLS-IRS-1). In these nuclear structures IRS-1 localizes at the periphery, and the core of the structure harbors a key autophagy protein, LC3; however, other autophagy proteins or biological membranes were not detected. In living cells expressing NLS-IRS-1-GFP fusion protein, IRS-1/LC3 structures are highly dynamic. They rapidly exchange IRS-1 molecules with nucleoplasm and interact with other nuclear complexes including BMI1-positive Polycomb bodies, PML bodies and Cajal bodies. Importantly, clones and mixed populations of cells expressing the NLS-IRS-1 and capable of forming the IRS-1/LC3 ring-like structures undergo extensive remodeling of gene expression, which suggests a transition to stem-like phenotype and associated resistance to several different anticancer drugs, including temozolomide. This is the first demonstration of IRS-1/LC3 nuclear complexes, which are highly dynamic and may play a role in epigenetic remodeling of glioblastoma cells towards stemness. Further studies are required to determine detailed molecular composition and to explain how these new nuclear structures function.
Citation Format: Adam Lassak, Dorota Wyczechowska, Anna Wilk, Adriana Zapata, Mathew Dean, Luis DelValle, Jann N. Sarkaria, Augusto Ochoas, Francesca Peruzzi, Krzysztof Reiss. IRS-1/LC3 nuclear structures and glioblastoma drug resistance. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 2520.
Abstract 2528: Mechanism and role of SOX2 repression in human germline specification
Authors: Ritu Kushwaha , Jagadish Nirmala , Bosl George , Chaganti Raju 
Published: July 2016

Abstract
The core pluripotency regulatory master transcription factor SOX2 is repressed in human primordial germ cells (PGCs) and in the seminoma (SEM) subset of human germ cell tumors (GCTs), which arises by transformation of PGCs. Neither the mechanism of this repression not its significance to GC and GCT development have so far been clarified. Here we show that SOX2 repression in TCam-2 SEM cells is mediated by the presence of the Polycomb repressive complex (PcG) and by the H3K27me3 chromatin mark at the SOX2 transcription start site. Moreover, repression can be abrogated by recruitment of the H3K27 demethylase UTX to the SOX2 promoter through retinoid signaling. SOX2-activated TCam-2 cells express neuronal and other lineage genes, consistent with the gene's function as a neurectodermal effector. Based on the recent discovery that SOX17 initiates human PGC specification, with its downstream target PRDM1 acting to suppress mesendodermal genes, we propose that SOX2 repression is required for PGC specification to suppress neuroectodermal genes. Overt pluripotency is initiated in latently pluripotent transformed PGCs presenting as the SOX2 upregulated embryonal carcinoma (EC) subset of GCTs; by gene expression profiling analysis we characterize the functional pathways that distinguish PGC-like unipotent SEM from blastocyst-like pluripotent EC.
Citation Format: Kushwaha Ritu, Nirmala Jagadish, George Bosl, Raju Chaganti. Mechanism and role of SOX2 repression in human germline specification. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 2528.
Abstract 2534: Low glucose and hypoxia environment promote the enrichment of liver cancer stem cells
Authors: Lai Chih Chung , Shia Tsu-Hsiang , Liu Yu-Peng , Yen Chia-Hung 
Published: July 2016

Abstract
Cancer stem cells (CSCs), a subpopulation possess tumor initiation and self-renewal capacity, are responsible for recurrence, metastases and drug resistance. Thus, it is important to understand their biology for identification of new therapeutic approaches. Liver surgery and/or transarterial (chemo) embolization (TAE/TACE) therapy usually generate a microenvironment that fosters aggressive tumor recurrence. These areas are characterized by chronic hypoxia and possibly low glucose concentration. Here, we tested the hypothesis that whether hypoxia along with low glucose environment promote the expansion of CSC population in HCC cells. We cultured human liver cancer cell line-Huh7 cells in normoxia or hypoxia condition with high or low glucose medium. The EMT markers (N-cadherin and Vimentin) but not stemness genes (CD44 and CD133) were upregulated in hypoxia condition. However, all genes were significantly induced under low glucose/hypoxia condition. In addition, results from sphere assay showed that low glucose/hypoxia condition dramatically improved the sphere formation ability of Huh7 cells, while low glucose or hypoxia along cannot promote sphere formation. Moreover, Huh7 cells cultured in low glucose/hypoxia condition displayed a lower sensitivity to cisplatin and doxorubicin treatment compared to cells maintained in high glucose/normoxia condition. Therefore, our findings suggested that low glucose concentration and hypoxia environment remarkably promote the enrichment of liver CSCs which could be useful for developing novel therapeutic modalities.
Citation Format: Chih Chung Lai, Tsu-Hsiang Shia, Yu-Peng Liu, Chia-Hung Yen. Low glucose and hypoxia environment promote the enrichment of liver cancer stem cells. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 2534.
Abstract 2537: Role of N-cadherin in connexin 43 mediated gap junctional formation between dormant breast cancer cells and bone marrow mesenchymal and stromal cells
Authors: Sinha Garima 
Published: July 2016

Abstract
Breast cancer (BC) remains a clinical problem. This is partly due to the existence of dormant BC cells (BCCs) in the bone marrow (BM) that could resurge decades after cancer remission. Cancer stem cells (CSCs) establish themselves in cycling quiescence within the BM microenvironment by forming gap junctional intercellular communication (GJIC) with mesenchymal stem cells (MSCs) and the hematopoietic supporting stroma. MiRNAs can be exchanged between the CSCs and other BM cells through the gap junction to impart cycling quiescence of the CSCs. Although the CSCs express several members of the connexin (Cx) family of proteins, GJIC between CSCs and BM cells requires Cx43. Preventing the formation of GJIC between CSCs and endogenous BM cells enhanced cycle of the BCCs with enhanced chemosensitivity. Since Cx43 is also involved in hematopoietic regulation, in order to identify targets to reverse dormancy, this study investigated the molecular mechanisms by which Cx43 is regulated, including the role of N-cadherin as a facilitator of GJIC between CSCs and BM cells. CSCs are epithelial-mesenchymal cells (EMT) and therefore express N-cadherin. In other studies Cx43 has been shown to interact with N-cadherin to facilitate the movement of Cx43 to the cell membrane. To this end, we hypothesize that the intracellular complex formed by N-cadherin and Cx43 in CSCs is regulated by the chemokine CXCL-12. MDA-MB-231, MDA-MB-468 and T47D were stimulated with different levels of CXCL12. At different times, the expression of N-cadherin was studied by real time PCR, confocal microscopy and flow cytometry. The results showed CXCL12 regulated both N-cadherin and Cx43. However, the outcome on their expression depended on the invasiveness of the tumor. Direct interaction between N-cadherin and Cx43 was demonstrated by time-line tracking for co-localization, molecular modeling and immunoprecipitation. In summary, this study showed that co-localization of N-cadherin and Cx43 is controlled by low level of CXC12. Ongoing studies are investigating how these findings affect GJIC between CSCs and BM stroma/MSCs.
Citation Format: Garima Sinha. Role of N-cadherin in connexin 43 mediated gap junctional formation between dormant breast cancer cells and bone marrow mesenchymal and stromal cells. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 2537.
Abstract 2538: The emerging role of SOX2 in cancer cell plasticity and EGFR-TKI resistance
Authors: Chiu Yu-Fan , Kuo Ming-Han , Lee An-Chun , Chou Yu-Ting 
Published: July 2016

Abstract
Activating mutations in the epidermal growth factor receptor (EGFR) lead to the aberrant growth of lung adenocarcinoma while endowing cancer cells with sensitivity to EGFR-tyrosine kinase inhibitors (TKIs). Nonetheless, EGFR-TKI resistance often occurs in less than one year. The intriguing phenomenon that cancer cells have biological features similar to stem cells suggests that cancer and stem cells may share the same regulatory signaling pathway, but the involvement of stem cell signaling in EGFR-TKI resistance is not clear. Herein, we observed that SOX2, a master transcriptional factor controlling self-renewal of lung stem cells, was highly expressed in lung adenocarcinoma and inversely correlated with epithelial-to-mesenchymal transition (EMT). Clonogenic analysis showed that SOX2-silenecing attenuated cell growth in EGFR-mutated lung cancer cells. The selection of EGFR-TKI resistant HCC827 (delE746_A750) cells induced EMT while attenuating the expression of SOX2 and spheroid forming ability. Preselection of HCC827 (delE746_A750) cells with EMT features endowed cells with TKI resistance but suppressed SOX2 expression. Pharmacological inhibition of HDACs in EGFR-mutated lung cancer cells attenuated SOX2 expression but induced EMT, thus enhancing the development of EGFR-TKI resistance. Our findings support the notion that the switching expression between SOX2 and EMT plays a critical role in EGFR-TKI resistance, with the potential as biomarkers for lung cancer prediction.
Citation Format: Yu-Fan Chiu, Ming-Han Kuo, An-Chun Lee, Yu-Ting Chou. The emerging role of SOX2 in cancer cell plasticity and EGFR-TKI resistance. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 2538.
Abstract 2539: Cell cycle regulation influences the phenotype of breast and prostate cancer stem cells in vitro
Authors: Feduska Joseph , Lee Carnellia , Ponnazhagan Selvarangan 
Published: July 2016

Abstract
The dissemination of metastases from the primary tumor accounts for over 90% of cancer-associated mortality. Despite advances on treatment modalities involving chemotherapeutic drugs, radiotherapy, and surgery, metastasis almost invariably arises by persistence of unresolved cancer cells following initial treatment. One intriguing explanation for this resiliency is the cancer stem-cell (CSC) hypothesis. According to the CSC model, phenotypic heterogeneity exists within the tumor, and a minority fraction of cells are able to reconstitute the tumor following ablation by current treatments. In like manner to their “normal” stem-cell counterparts, CSCs are capable of unlimited self-renewal, and the ability to “differentiate” to reconstitute the phenotypic heterogeneity of the initial tumor. Recent studies have sought to identify cancer stem cells in numerous types of solid tumors, including breast and prostate. Among the cell surface antigens utilized to identify the CSC subpopulations are CD24, CD44, CD133, and other factors associated with epithelial-to-mesenchymal transition (EMT).
In this study, we sought to investigate the phenotypic changes associated with cell-cycle in breast (BCa-SC) and prostate (PCa-SC) cancer. We characterized in vitro the malignant and osteolytic human breast cancer cell line MDA-MB-231 and human prostate cancer cell line PC3, with the goal of identifying an optimal checkpoint where the CSC subpopulation would be most vulnerable to subsequent targeted chemotherapy. We found that common CSC markers are expressed in a time-dependent manner due to changes in the cell cycle. Our hypothesis is that temporal inhibition of the cell cycle when the CSC phenotype is least prominent will circumvent the chemo-resistance inherent to CSC.
Citation Format: Joseph Feduska, Carnellia Lee, Selvarangan Ponnazhagan. Cell cycle regulation influences the phenotype of breast and prostate cancer stem cells in vitro. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 2539.