bluuebunny/crossref_metadata_2025_split huggingface dataset:
Abstract 2775: Development and characterization of a MEK1 inhibitor (AZD6244) sensitive childhood astrocytoma cell line
Authors: Studebaker Adam W. , Bid Hemant K. , Phelps Doris A. , Houghton Peter J. 
Published: May 2015

Abstract
We previously characterized the development and reversal of acquired resistance to the MEK1 inhibitor AZD6244 in an in vivo model of childhood astrocytoma. The BT-40 astrocytoma xenograft model expresses mutated BRAFV600E and is highly sensitive to AZD6244, but acquires resistance, which can be overcome with the addition of the STAT3 inhibitor LLL12. The purpose of this current study was to establish and characterize a cell line derived from the xenograft model as well as develop an orthotopic mouse model. Sensitivity to AZD6244 and LLL12, expression-profiling assessment of MEK signature and compensatory pathways, and cytokine levels were assessed in the newly developed BT-40 cell line. The BT-40 cell line exhibited sensitivity to AZD6244 and LLL12 with IC50 values of 350nM and 1µM, respectively. Combination treatment was additive. Treatment of the cells with AZD6244 inhibited p-Erk and the mTOR downstream signaling molecule p-S6, while p-Akt, p-STAT3, p-4E-BP1 increased. Kinase expression arrays performed on cells treated with AZD6244 displayed a decrease in IL-1α, G-CSF, and IL-6 and an increase in CXCL10. The decrease in IL-6 was restored to baseline levels with the addition of LLL12. Interestingly, the JAK2 inhibitor AZD1480 failed to restore the IL-6 levels. The IL-6 results observed in the expression arrays were confirmed by ELISA, where AZD6244 decreased soluble IL-6 levels and LLL12, but not AZD1480, restored IL-6 levels to baseline. The BT-40 cell line, along with a cell line stably expressing luciferase (BT-40Luc), were implanted into the caudate putamen using stereotaxic guidance. The BT-40Luc cells exhibited exponential growth over time as evaluated with bioluminescent imaging. In conclusion, a cell line derived from a previously described in vivo model of childhood astrocytoma was developed that closely recapitulated our original findings in the xenograft model following treatment with the MEK1 inhibitor AZD6244. Furthermore, an orthotopic model of these cells was developed, which will allow us to characterize response to established and novel therapeutic agents. Supported by PHS award CA169368.
Citation Format: Adam W. Studebaker, Hemant K. Bid, Doris A. Phelps, Peter J. Houghton. Development and characterization of a MEK1 inhibitor (AZD6244) sensitive childhood astrocytoma cell line. [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 2775. doi:10.1158/1538-7445.AM2014-2775
Abstract 2778: Lapatinib inhibits CIP2A/PP2A/p-Akt signaling and induces apoptosis in triple negative breast cancer cells
Authors: Tseng Ling-Min , Liu Chun-Yu , Hsu Chia-Jung , Wang Duen-Shian , Su Jung-Chen , Shiau Chung-Wai , Chen Kuen-Feng 
Published: May 2015

Abstract
Background: Triple-negative breast cancer (TNBC) is a subtype with aggressive behaviors and poor prognosis. Our previous study has shown that CIP2A, cancerous inhibitor of PP2A, may be a novel target in breast cancer cells (Breast Cancer Research 2012). Here, we tested efficacy of lapatinib, a dual tyrosine kinase inhibitor which interrupts the HER2/neu and epidermal growth factor receptor (EGFR) pathways, in a panel of TNBC cell lines and examined the drug mechanism.
Methods: TNBC cell lines (HCC-1937, MDA-MB-468, MDA-MB-231) were used for in vitro studies. Apoptosis was examined by both flow cytometry and Western blot. Signal transduction pathways in cells were assessed by Western Blot. Quantitative RT-PCR was used for assessing gene transcription. In vivo efficacy of lapatinib was tested in nude mice with breast cancer xenografts.
Results: Lapatinib showed anti-proliferative effect in HCC 1937, MDA-MB-468, and MDA-MB-231 cell lines. Lapatinib induced significant apoptosis in dose-dependent and time-dependent manners in the three tested TNBC cell lines. Importantly, lapatinib inhibited CIP2A and p-Akt in a dose-dependent manner in all sensitive TNBC cells. Overexpression of CIP2A protected MDA-MB-468 cells from lapatinib-induced apoptosis. In addition, lapatinib increased PP2A activity (in relation to CIP2A inhibition) in sensitive cells. Moreover, lapatinib-induced apoptosis as well as lapatinib-induced p-Akt downregulation, was attenuated by PP2A antagonist okadaic acid in sensitive cells. Lapatinib downregulated CIP2A mRNA. Importantly, lapatinib showed anti-tumor activity in mice bearing MDA-MB-468 xenograft tumors, and downregulated CIP2A as well as p-Akt in these xenografted tumors.
Conclusions: Inhibition of CIP2A determines the effects of lapatinib-induced apoptosis in TNBC cells. Our data suggest that in addition to a dual tyrosine kinase inhibitor of HER2/neu and EGFR, lapatinib can be a novel CIP2A inhibitor and that CIP2A can be a potential target for TNBC.
(Supported by Yen Tjing Ling Medical Foundation; NSC 101-2325-B-075-006, NSC-102-2325-B-075-006 and NSC 100-2325-B-010-007; and V100-D-005-4)
Citation Format: Ling-Min Tseng, Chun-Yu Liu, Chia-Jung Hsu, Duen-Shian Wang, Jung-Chen Su, Chung-Wai Shiau, Kuen-Feng Chen. Lapatinib inhibits CIP2A/PP2A/p-Akt signaling and induces apoptosis in triple negative 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 2778. doi:10.1158/1538-7445.AM2014-2778
Abstract 2781: Elimination of PanIn2/3 in a GEMM for pancreatic cancer with disrupted p16 and activated Kras
Authors: Dinnen Richard D. , Qiu Wanglong , Su Gloria H. , Petrylak Daniel P. , Fine Robert L. 
Published: May 2015

Abstract
When treated with clinically achievable concentrations of arsenic trioxide, ascorbic acid and antabuse (disulfiram) (AAA), we found that four human pancreatic cancer cell lines underwent robust cell death associated with ATP decline and ROS accumulation. In these cells, early apoptosis shifted to aponecrosis, and was dependent on VDAC since shRNA antagonistic to VDAC-1 abrogated the ROS accumulation and blocked cell death. In this study, assessment of AAA was performed in Pdx1-Cre transgenic mice with a conditional p16 knockout (p16flox/flox), and oncogenic KrasG12D. The KrasG12D, p16flox/flox; LSL-KrasG12D; Pdx1-Cre mice develop a full spectrum of pancreatic intraepithelial neoplasia (PanIN) lesions, pancreatic ductal adenocarcinoma (PDA), and frequent metastases. Eight week old mice were treated for 8 weeks, 3 times/week with AAA, sacrificed, and assessed for the development of pancreatic cancer. Little or no toxicity was observed in the AAA-treated mice. The development of frank pancreatic tumors was decreased from 37% in controls to 0% in AAA-treated mice. The mean number of PanIN 3 lesions/mouse declined from 14.2 in controls to 1.6 in AAA-treated mice (p=0.004); the mean number of PanIN 2 lesions declined from 5.8 in controls to 1.7 in AAA-treated mice (p=0.029), and the mean number of PanIN 1 lesions in control mice was 14.2 and in AAA-treated mice was 16.0 (p=0.82), indicating no difference in PanIN 1 occurrence between control and AAA-treated mice. The data also suggests that PanIN 2 and PanIN 3 lesions are killed after exposure to AAA, since mice prior to treatment had high levels of PanIN 2 (8.1 lesions/mouse) and PanIN 3 (11.4 lesions/mouse), similar to controls at 4 months of age. Therefore, AAA may have eliminated pre-existing PanINs rather than blocking their development. Results from immunohistochemical staining of the PanIN lesions for VDAC, indicated that PanIN 1 lesions have low, and PanIN 2 and 3 lesions have high, VDAC expression. This result parallels the in vitro human cell line data showing VDAC expression is critical to AAA sensitivity, and suggests a similar mechanism of action in the murine model, as we see in vitro. This is the first treatment that has shown potential to kill existing PanIN lesions and arrest the development of tumors in this pancreatic cancer murine model.
Citation Format: Richard D. Dinnen, Wanglong Qiu, Gloria H. Su, Daniel P. Petrylak, Robert L. Fine. Elimination of PanIn2/3 in a GEMM for pancreatic cancer with disrupted p16 and activated Kras. [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 2781. doi:10.1158/1538-7445.AM2014-2781
Abstract 2789: Iron chelation inhibits mTOR activity in cancer cells
Authors: Shang Chaowei , Zhou Hongyu , Huang Shile 
Published: May 2015

Abstract
Mammalian target of rapamycin (mTOR) plays a critical role in regulating cell proliferation and survival through sensing environmental cues. mTOR functions as at least two complexes (mTORC1/2). In cancer cells, mTOR activity is often deregulated. Intracellular iron levels are higher in cancer cells than in normal cells mainly due to the increased requirement of iron for proliferation. Thus, cancer cells are more sensitive to iron chelation than normal cells. Iron chelators have been used as traditional treatment for iron overload diseases. Recent studies have shown that iron chelators possess potent anticancer activity. However, the underlying mechanism is not well understood. In this study, we found that ciclopirox olamine (CPX), an iron chelator and off-patent antifungal drug, inhibited cell proliferation and induced cell death in human head and neck cancer cells (PCI-13 and FaDu), breast adenocarcinoma (MDA-MB-231), human rhabdomyosarcoma (Rh30), and skin squamous cell carcinoma (SRB-M7) cells. Similar results were observed using Dp44mT, another iron chelator. Concurrently, CPX and Dp44mT inhibited mTORC1 signaling in the cells. This is evidenced by the findings that treatment with the iron chelators inhibited phosphorylation of 4E-BP1 and S6K1, two best known effector molecules of mTORC1, which could be blocked by addition of ferrous sulfate, but not cuprous sulfate. At the same time, the addition of ferrous sulfate prevented cancer cell death. The findings suggest that the inhibitory effect of CPX or Dp44mT on mTORC1 function was attributed to selective chelation of iron in the cells. Mechanistically, chelation of iron did not activate protein phosphatase 2A (PP2A), but induced raptor (S792) phosphorylation and disrupted mTORC1 integrity. Of note, the effect of iron chelation on mTORC2 was cell line dependent. Further research may enhance our understanding the role of iron in the regulation of mTOR signaling.
Citation Format: Chaowei Shang, Hongyu Zhou, Shile Huang. Iron chelation inhibits mTOR activity in 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 2789. doi:10.1158/1538-7445.AM2014-2789
Abstract 2792: Engineering T lymphocytes with protein nanogels for cancer immunotherapy
Authors: Tang Li , Zheng Yiran , Irvine Darrell J. 
Published: May 2015

Abstract
Adoptive cell transfer (ACT) with autologous tumor-reactive T-lymphocytes is a promising strategy in cancer immunotherapy, but treatment of solid tumors is limited by the rapid decline in function of the transplanted T cells. In order to maintain high numbers of viable tumor-specific cytotoxic T cells in tumors, co-administration of supporting immunostimulant agents together with transferred cells is typically necessary in clinical practice. When given systemically at high doses, these agents could enhance the in vivo viability of donor cells, improve their therapeutic function and lead to overall improved efficacy against cancer. However, high doses of such agents can also result in serious side effects. For example, the use of Interleukin-2 (IL-2) as an adjuvant drug significantly enhances the efficacy of ACT in melanoma, where IL-2 provides key adjuvant signals to donor T cells but also elicits severe dose-limiting inflammatory toxicity and expands regulatory T cells (Tregs). One approach to focus adjuvant drug action on the transferred cells and lower systemic toxicity is to genetically engineer donor cells to secrete their own supporting factors. However, the technical difficulty of engineering safe autocrine production of potent adjuvant molecules such as cytokines is a challenge. Thus, an inexpensive technology platform that would allow simple, safe and efficient delivery of adjuvant drugs specifically to therapeutic cells over a defined window of time could be broadly useful in ACT and other cell therapies for cancer. Here, we developed a novel strategy to deliver therapeutic proteins in T cell therapies, via the chemical conjugation of protein-polyethylene glycol (PEG) nanogels (NGs) directly onto the plasma membrane of donor cells, enabling continuous pseudoautocrine release of cargo proteins for stimulation of transferred T-cells. These PEG NGs loaded with IL-2 contained very high level of drug (∼80 wt% of NG was the protein cargo) and released native IL-2 in physiological conditions in a sustained manner through breakdown of a degradable linker between the IL-2 cargo and PEG chains of the NG. T-cells with optimized number of NGs conjugated per cell maintained their cellular functions and cancer targeting and killing capability. We demonstrated that this IL2-PEG NG-T cell conjugation strategy could augment T-cell expansion in vivo and result in markedly improved efficacy against metastatic B16F10 melanoma in mice. This approach provides a readily generalizable strategy to provide autocrine protein drug support to donor cells to enhance the safety and efficacy of ACT.
Citation Format: Li Tang, Yiran Zheng, Darrell J. Irvine. Engineering T lymphocytes with protein nanogels for cancer immunotherapy. [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 2792. doi:10.1158/1538-7445.AM2014-2792
Abstract 2798: Targeting IL13R alpha2 heterogeneity in malignant glioma with engineered T cells
Authors: Sengupta Sadhak , Balyasnikova Irina , Naheed Seema , Lesniak Maciej S. , Junghans Richard P. , Sampath Prakash 
Published: May 2015

Abstract
A majority of malignant glioma exclusively expresses Interleukin 13 receptor alpha chain variant 2 (IL13Rα2), making it an ideal candidate for targeted immunotherapy. A number of immunotherapeutic molecules have been developed against IL13Rα2 with varied levels of therapeutic efficacy. However, the importance of IL13Rα2 as a successful immunotherapy candidate is under scrutiny due to its heterogeneous expression on the tumor. We have used an IL13-chimeric antigen receptor (IL13CAR) expressing T cells to target the IL13Rα2 heterogeneity on malignant glioma. IL13Rα2 was over-expressed on U251MG human glioma cell line by stable transfection (IL13Rα2Hi) to evaluate the effects of its increased expression in tumor progression and immunotherapeutic efficacy, compared to the regular U251 cells (IL13Rα2Lo) and IL13Rα2-knocked down U251 cells (IL13Rα2KD). Tumor cells readily formed neurospheres under established culture conditions. Increased expression of IL13Rα2 was observed in IL13Rα2Hi-neurosphere derived tumor cells when compared to those derived from IL13Rα2Lo neurospheres, as well as the parental IL13Rα2Hi cells. IL13Rα2Hi-neurosphere derived tumor cells were also resistant to radiation therapy and temozolomide chemotherapy when compared to those IL13Rα2Lo neurospheres-derived tumor cells, as well as parental cell lines. Higher levels of IFN gamma and TNF alpha in the culture supernatants, increased T cell proliferation, and CAR+ TCR enrichment were observed when IL13CAR T cells were co-cultured with IL13Rα2Hi-neurosphere derived tumor cells, in comparison to co-culture with IL13Rα2Lo -neurosphere derived tumor cells, as well as the parental cells. IL13CAR T cells, upon co-culture with IL13Rα2Hi-neurosphere derived tumor cells exerted highest levels of cytotoxicity. Together, these results predict that IL13Rα2 heterogeneity can be addressed by a combination of established therapeutic regimen and targeted immunotherapy. While those cells expressing lower levels of IL13Rα2 are susceptible to radiation and chemotherapy, the high IL13Rα2-expressing tumor cells that escape these treatments can be candidates for IL13Rα2-targeted immunotherapy.
Note: This abstract was not presented at the meeting.
Citation Format: Sadhak Sengupta, Irina Balyasnikova, Seema Naheed, Maciej S. Lesniak, Richard P. Junghans, Prakash Sampath. Targeting IL13R alpha2 heterogeneity in malignant glioma with engineered T 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 2798. doi:10.1158/1538-7445.AM2014-2798
Abstract 28: The influence of PDGF and VEGF on tumor proliferation in colon cancer
Authors: Mönch Romana , Grimmig Tanja , Kannen Vinicius , Germer Christoph T. , Waaga-Gasser Ana Maria , Gasser Martin 
Published: May 2015

Abstract
Background: The platelet derived growth factor (PDGF) and Vascular Endothelial Growth Factor (VEGF) are known to play a crucial role in different tumor entities. Involved in cell migration and proliferation of stromal cells and tumor cells they represent key targets in cancer therapy. The aim of the study was to analyse the specific role of PDGF and VEGF stimulation on tumor cell proliferation and metabolism in colorectal cancer (CRC).
Methods: The human colon cancer cell line HT-29 and Caco-2 were cultured and stimulated with PDGF and VEGF in a time-dependent manner. Whole cell extracts and RNA extracts were analyzed by Western Blot and RT-q-PCR for PDGF- and VEGF receptors and for components of cellular metabolism. To discover effects of PDGF and VEGF on proliferation MTS proliferation assays were performed.
Results: Western Blot analysis and RT-qPCR showed no relevant PDGF-receptor α and β expression in HT-29 cells but varying expression in Caco-2 cells. Stimulation with PDGF or VEGF resulted in increased proliferation compared to untreated controls while simultaneous stimulation with both growth factors did not result in intensified proliferation. Additionally, under stimulation altered expression of various metabolic components was detected.
Conclusion: Our results demonstrate a promoting effect on tumor cell proliferation of both growth factors VEGF and PDGF. Simultaneous stimulation did not show synergistic effects. PDGF in HT-29 cells resulted in proliferation in the absence of PDGF receptors with changes in tumor cell metabolism after stimulation. Moreover in HT-29 cells glucose metabolism changed during stimulation. In conclusion, our data give evidence for direct receptor/ligand signalling of PDGF not only on stromal cells but also on colon cancer cells even in the absence of the PDGF receptor.
Citation Format: Romana Mönch, Tanja Grimmig, Vinicius Kannen, Christoph T. Germer, Ana Maria Waaga-Gasser, Martin Gasser. The influence of PDGF and VEGF on tumor proliferation in colon 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 28. doi:10.1158/1538-7445.AM2014-28
Abstract 2802: Fine-tuning T cell receptors for adoptive T cell therapy
Authors: Jakobsen Bent 
Published: May 2015

Abstract
Adoptive T cell therapy (ACT) with gene-modified T cells is emerging as a highly promising strategy for the treatment of many types of cancer. Therapies associated with the induction of anti-tumor immunity, such as the administration of vaccines or the ex-vivo expansion of patient-derived TILs, have historically had limited success. This lack of efficacy is almost certainly brought about as a consequence of thymic selection, leading to a paucity of T cells, and T cell receptors, in the circulating repertoire, with a sufficient degree of sensitivity towards tumor-associated antigens. An alternative approach, which has generated promising results, relies on the adoptive transfer of patient-derived T cells that have been first modified to express a chimeric antigen receptor (CAR). Nevertheless, a lack of tumor-specific antibody targets limits the wider applicability of CAR T cells.
To overcome these issues we have developed a strategy that involves the transfer of T cells expressing engineered TCRs with optimised affinity for a defined tumor antigen. Since TCRs recognize peptide antigens presented on the cell surface in complex with human leukocyte antigen (HLA), they give access to the large pool of intracellular proteins. Furthermore, the use of TCRs means that the natural interaction between a T cell and the corresponding antigen presenting cell is preserved. Importantly, for any given antigen, engineered TCRs require individual optimization, to ensure the appropriate balance between potency and specificity.
Recent and emerging clinical data using engineered TCRs for ACT are beginning to corroborate promising pre-clinical findings, with evidence of both potent and durable responses in vivo. However, experiences have also highlighted the dangers of this approach. The main risks associated with TCR adoptive therapy are target presentation on healthy tissue and TCR cross-reactivity to a look-alike peptide. Understanding these risks and ensuring comprehensive and robust safety testing mechanisms are in place is pivotal to mitigate these risks.
Citation Format: Bent Jakobsen. Fine-tuning T cell receptors for adoptive T cell therapy. [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 2802. doi:10.1158/1538-7445.AM2014-2802