bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 1937: In-depth genomic analysis reveals complex functional consequence of driver mutations in breast cancers
Authors: Xu Yaomin , Guo Xingyi , Zhao Shilin , Torstenson Eric , Edwards Todd , Shyr Yu
Published: August 2015

Understanding the extensive functional consequences of molecular drivers of a cancer is challenging. We developed an in-depth genomic analytical framework to identify the gene and pathway targets dysregulated by somatic driver mutations. Using The Cancer Genome Atlas (TCGA) breast cancer data, we systemically analyzed all high frequent mutation events including amplification, deletion and point mutation across tumor tissues. Those include the known molecular driver genes such as PIK3CA, GATA3, PTEN and TP53. Utilizing bagging with distance-based regression for differential gene expression analysis, we identified several thousands gene targets associated with the somatic mutations. Integrating gene co-expression regulatory network and the association dependence structure among the somatic mutations, we explored a complex association network of molecular pathway modules or sub-modules that are specific to a mutational event or common to a set of events. Interestingly, we found those modules commonly associated with sets of mutation events were significantly enriched in well-known breast cancer related pathways such as ERBB2, PI3AK and TGFB1. Combined with the publicly available data of a genome-wide RNA-mediated interference screen in breast cancer, we further demonstrated that those modules enriched with cell proliferation essential genes. Our analysis strategy provides a novel view of complex functional mechanism driven by the driver mutation events and it has high potential to provide novel insights to the understanding of the tumorigenesis or the development of therapeutic targets.

Citation Format: Yaomin Xu, Xingyi Guo, Shilin Zhao, Eric Torstenson, Todd Edwards, Yu Shyr. In-depth genomic analysis reveals complex functional consequence of driver mutations in breast cancers. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 1937. doi:10.1158/1538-7445.AM2015-1937
Abstract 1942: Regulation of GRNMB transcription and cellular effects by chondroitin 4-sulfation
Authors: Tobacman Joanne Kramer , Feferman Leo , Bhattacharyya Sumit
Published: August 2015

Increased expression of glycoprotein (transmembrane) NMB (GPNMB; osteoactivin) has been identified in triple negative breast cancer, melanoma, glioma, and hepatocellular carcinoma, and followed decline in expression of the enzyme arylsulfatase B (ARSB; N-acetylgalactosamine 4-sulfatase). The expression and regulation of GPNMB was evaluated in HepG2 cells and in ARSB-deficient and control C57BL/6J mouse hepatic tissue. Increased expression of GPNMB was attributable to promoter activation by phospho(Ser)MITF (microphthalmia-associated transcription factor), the phosphorylation of which was activated by phospho(Ser)-p38 MAPK. When ARSB was reduced, nuclear phospho-MITF increased and GPNMB promoter activity increased, as detected by Renilla reniformis luciferase assay. Chromatin immunoprecipitation assay confirmed that phospho-MITF bound to a specific motif in the GPNMB promoter, and binding increased when ARSB was silenced. Up-regulation of promoter activity increased the expression of GPNMB message and the synthesis of GPNMB protein in the HepG2 cells and ARSB-null mouse liver. The tyrosine phosphatase SHP2 bound more tightly to C4S when ARSB was reduced, leading to inhibition of SHP2 activity and reduced removal of phosphate from Tyr182 of phospho-p38 MAPK. The increase in C4S stimulated phospho(Ser)-p38 MAPK by activation of RhoA, leading to MITF phosphorylation and increased GPNMB expression. Silencing GPNMB by siRNA reduced phosphorylation of ERK and expression of matrix metalloproteinase (MMP)-9, consistent with effects on hepatic cell invasiveness. These findings indicate that ARSB-induced changes in chondroitin 4-sulfation impact on critical phosphorylations mediated by SHP2 and p38 MAPK, leading to activation of MITF and increased expression of GPNMB. The interaction between chondroitin 4-sulfation and phosphorylations may regulate vital cell processes, including transcriptional events and cell-matrix interactions.

Citation Format: Joanne Kramer Tobacman, Leo Feferman, Sumit Bhattacharyya. Regulation of GRNMB transcription and cellular effects by chondroitin 4-sulfation. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 1942. doi:10.1158/1538-7445.AM2015-1942
Abstract 1950: Emerging role of CITED2 in hypoxia and TGF-beta mediated proliferation and invasion in lung cancer
Authors: Kuo Ming-Han , Hsieh Cheng-Han , Wang Yuan-Hung , Wu Cheng-Wen , Chou Yu-Ting
Published: August 2015

Lung cancer remains the leading cause of cancer mortality in the world. Metastatic property is one of the major reasons for treatment failure in lung cancer patients. Tumor microenvironment plays a key role in shaping tumor progression. In solid tumors, a decreased oxygen and nutrient supply creates a hypoxic microenvironment in the central region, which elicits a set of genes to endow cancer cells with increased survival or proliferation abilities. On the other hand, TGF-beta, which is often released by tumor stroma cells, attenuates cell proliferation but induces invasion of lung cancer. How cancer cells are shaped by tumor microenvironment with elevated proliferation and invasion abilities are elusive. Here, we report that CITED2, a MYC interacting transcriptional modulator, responds to hypoxia induction and TGF-beta suppression to orchestrate cellular proliferation and invasion, respectively. We observed that hypoxia induced CITED2 expression in a group of lung cancer cells, the proliferation and survival of which were dependent on CITED2 signaling. TGF-beta stimulation inhibited CITED2 expression, causing decreased cell proliferation. Nonetheless, hypoxia potentiated TGF-beta mediated invasion and rendered cell resistant to TGF-beta induced cell growth arrest by elevating CITED2 dependent signaling. Our findings provide that CITED2 functions as an oncogeneic switch for hypoxia and TGF-beta mediated proliferation and invasion in lung cancer, deserving additional evaluation as a biomarker for lung cancer progression.

Citation Format: Ming-Han Kuo, Cheng-Han Hsieh, Yuan-Hung Wang, Cheng-Wen Wu, Yu-Ting Chou. Emerging role of CITED2 in hypoxia and TGF-beta mediated proliferation and invasion in lung cancer. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 1950. doi:10.1158/1538-7445.AM2015-1950
Abstract 1953: Group I Paks as therapeutic targets in NF2-deficient meningioma
Authors: Chow Hoi Yee
Published: August 2015

Neurofibromatosis type 2 (NF2) is an autosomal dominant disorder characterized by the development of multiple tumors in the central nervous system, most notably schwannomas and meningiomas. Mutational inactivation of NF2 is found in 40-60% of sporadic meningiomas, but the molecular mechanisms underlying malignant changes of meningioma cells remain unclear. Because group I p21-activated kinases (Paks) bind to and are inhibited by the NF2-encoded protein Merlin, we assessed the signaling and anti-tumor effects of three group-I specific Pak inhibitors - Frax597, 716 and 1036 - in NF2-/- meningiomas in vitro and in an orthotopic mouse model. We found that these Pak inhibitors suppressed the proliferation and motility of both benign (Ben-Men1) and malignant (KT21-MG1) meningiomas cells. In addition, we found a strong reduction in phosphorylation of Mek and S6, and decreased cyclin D1 expression in both cell lines after treatment with Pak inhibitors. Using intracranial xenografts of luciferase-expressing KT21-MG1 cells, we found that treated mice showed significant tumor suppression for all three Pak inhibitors. Similar effects were observed in Ben-Men1 cells. Tumors dissected from treated animals exhibited an increase in apoptosis without notable change in proliferation. Collectively, these results suggest that Pak inhibitors might be useful agents in treating NF2-deficient meningiomas.

Citation Format: Hoi Yee Chow. Group I Paks as therapeutic targets in NF2-deficient meningioma. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 1953. doi:10.1158/1538-7445.AM2015-1953
Abstract 1966: Role of Wnt-Beta-Catenin signals in the control of vascular mimicry in TNBC
Authors: Leyland-Jones Brian , Carlson Jennifer H. , De Pradip , Dey Nandini
Published: August 2015

Background: TNBC or basal-like subtype of breast cancer confers poor clinical outcome mostly due to its inherent aggressive nature and its high frequency of metastasis. Malignancy in TNBC is associatedwith micro-vascular proliferations. Vascular Mimicry (VM) of solid tumor is an endothelium-independent matrix-embedded, blood-perfused non-angiogenic micro-circulatory phenomenon. VM of tumor cells refer to the characteristic plasticity of aggressive cancer cells forming de novo vascular networks which perfuse rapidly growing tumors, transporting fluid from leaky vessels and/or connect with the constitutional endothelial-lined vasculature. In a study comparing the VM in three subsets of BC, the presence of VM was more profoundly observed in TNBC than in luminal and HER2+ subtypes.

Hypothesis: Recently we have identified a differential activation of Wnt-b-Catenin pathway (WP) in TNBC (Dey et al., PLOSONE; 2014) and demonstrated that Wnt signaling in TNBC is association with metastasis (Dey et al., BMC Cancer 2013). Since TNBC is an aggressive form of BC and VM is associated with the aggressiveness / poor outcome in many solid tumors including BC, we hypothesized that the upregulation of WP in TNBC may have a functional relationship with VM.

Methods: Four strategies were used to study the role of WP in VM. They are (1) Wnt-receptor interaction by using WntC59, (2) Wnt cytosolic signaling by using XAV939, (3) Wnt nuclear signaling by using sulindac sulfide and beta-catenin SiRNA and (4) Wnt-regulating pathway by using pan-PI3K inhibitor (LY294002 and SF1126). The signaling of VM was characterized by bevacizumab (HUVEC cell cord formation used as positive control).

Results: Using pharmacological and genetic tools, we demonstrated that perturbation of WP (1) at its different nodes and (2) via its upstream regulatory pathway (PI3K) can regulate VM in TNBC cells. Data showed that (1) sulindac sulfide, (2) XAV939 and WntC59 and (3) LY294002 or SF1126 (which decreased pGSK3beta) caused an abrogation of VM in TNBC cell lines while bevacizumab failed to affect the vessel formation. Considering the involvement of VM in mediating the aggressive/metastatic nature of TNBC, we finally tested the effect of downregulation of WP on VM in brain metastasis specific EGFP-tagged MDA-MB231BR cells using a real time recording device (Incucyte) to demonstrate that VM in these cells is regulated by WP.

Significance: To our knowledge, this is the first report to demonstrate a direct functional role of WP in the regulation of VM in TNBC.

Citation Format: Brian Leyland-Jones, Jennifer H. Carlson, Pradip De, Nandini Dey. Role of Wnt-Beta-Catenin signals in the control of vascular mimicry in TNBC. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 1966. doi:10.1158/1538-7445.AM2015-1966
Abstract 1968: Activation of AKT negatively regulates the pro-apoptotic function of death-associated protein kinase 3 (DAPK3) in prostate cancer
Authors: Das Trinath P. , Papu John Arokya MS , Roy Ram V. , Rao Sandhya R. , Alatassi Houda , Damodaran Chendil , Ankhem Murali M.
Published: August 2015

Activation of AKT plays a central role by inducing pro-survival signaling pathways, promotes cell growth and inhibits apoptosis in human malignancies including prostate cancer. Higher expression of pAKT is correlated with aggressiveness of the prostate cancer. Published evidences suggest that inhibition of survival kinases may utilize the current therapeutic modalities to sensitize the prostate cancer cells more significantly. Indeed, numbers of small molecules or peptides are being developed to inhibit either AKT or its upstream kinase PI3K to inhibit the growth of human malignances. Death-associated protein kinase 3 (DAPK3), a serine/threonine kinase governs many signaling pathways including induction of apoptosis.

This lead the way to focus our research on small molecules which can inhibit AKT activation and induce DAPK mediated apoptosis in CaP cell lines. To begin with, we identified a small molecule which binds to AKT kinase domain with a predicted affinity of ∼11.0 Kcal/mol. The amino acid residues of AKT-1 within 4 Å of the best docking site of this small molecule, 6-dimethyl, dihydro pyranone (6ddp), includes ARG-4, SER-7, LEU-156, GLY-157, LYS-158, GLY-159, PHE-161, VAL-164, LYS -179, GLU-191, HIS-194, GLU-234, ASP-274, MET-281, ASP-292, GLY-294,LEU-295, and PHE-438. The hydroxyl group of 6ddp likely forms a hydrogen bond with the nitrogen on the side chain of HIS-194. 6ddp inhibited pAKT (ser473) expression which concomitantly induced DAPK1 expression resulting in the growth inhibition of CaP cell lines. Similar results were obtained when a pharmacological inhibitor of AKT was used which resulted in DAPK induced apoptosis of CaP cells. Subsequently, we examined the DAPK3 activation in prostate cancer samples, which significantly showed a higher expression in normal prostate samples. On the contrary, reduced expression with low level was observed with the progression of disease. Currently, our study focuses on the kinase and phosphatase interaction network by mass spectrometric analysis of protein complexes. Understanding the mechanism of DAPK3 mediated AKT inhibition, may strengthen the therapeutic window for prostate cancer without causing much or any toxicity

Citation Format: Trinath P. Das, Arokya MS Papu John, Ram V. Roy, Sandhya R. Rao, Houda Alatassi, Chendil Damodaran, Murali M. Ankhem. Activation of AKT negatively regulates the pro-apoptotic function of death-associated protein kinase 3 (DAPK3) in prostate cancer. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 1968. doi:10.1158/1538-7445.AM2015-1968
Abstract 1979: Regulation of the oncogene ZNF217 by localization in breast cancer
Authors: Messana Matthew J. , Littlepage Laurie E.
Published: August 2015

Poor prognosis in breast cancer patients occurs when malignant tumors adapt to environmental insults, become resistant to chemotherapy, evade immune surveillance and metastasize to other tissues. Tumors are thought to arise from individual cells with multiple mutations, including amplification of genomic regions that provide a growth advantage. A region on human chromosome 20 called 20q13 is increased in ∼25% of early stage human breast cancers and correlates with poor prognosis in patients. We have studied a novel oncogene ZNF217 within this region. ZNF217 is key in promoting breast cancer: it is not only a prognostic indicator of breast cancer progression in patients who have the worst prognosis but also is itself a drug target and/or marker of patient response to therapy. We find that ZNF217 protein is expressed most strongly in a small subset of cells within normal mammary epithelium and localizes predominantly in the nucleus of mammary epithelial cells. In contrast, the localization of ZNF217 is heterogeneous in breast tumors, with localization in both the nucleus and cytoplasm. Moreover, a truncated form of the protein localizes exclusively in the cytoplasm. We hypothesize that ZNF217 cytoplasmic localization affects ZNF217 function during cancer progression and can be used to predict poor prognosis in breast cancer patients. We have stained human breast tissue and human mammary epithelial cells for ZNF217 and find heterogeneous localization of ZNF217 across the samples. We now will identify the regions of ZNF217 that are required for ZNF217 localization in the nucleus and cytoplasm. We will utilize integrated biological approaches to determine the consequences of mis-localization of ZNF217 on cancer progression. Using our truncation mutants, we will determine which regions of ZNF217 are required for oncogenesis by overexpressing ZNF217 truncations in mammary epithelial cells and using these cells in a variety of assays that model steps in cancer progression assays that have previously shown that ZNF217 promotes cancer progression.

Citation Format: Matthew J. Messana, Laurie E. Littlepage. Regulation of the oncogene ZNF217 by localization in breast cancer. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 1979. doi:10.1158/1538-7445.AM2015-1979
Abstract 1983: Aryl hydrocarbon receptor activates NDRG1 transcription under hypoxia in breast cancer cells
Authors: Li En-Yu , Huang Wei-Yung , Tsai Mong-Hsun , Chuang Eric Y. , Lai Liang-Chuan
Published: August 2015

Hypoxia has been intensively investigated over past decades based on the observations that hypoxic tumors were more resistant to therapy and had a worse prognosis. Previously, we reported that N-myc downstream-regulated gene 1 (NDRG1) was strongly up-regulated under hypoxia and may play an important role in tumor adaptation to fluctuation of oxygen concentrations. However, the regulatory mechanism of NDRG1 under hypoxia remains elusive. Therefore, the purpose of this study is to identify the novel transcription factors that regulate NDRG1 and to investigate the functional roles of NDRG1 in hypoxia. In silico analysis predicted binding sites of aryl hydrocarbon receptor (AHR) existing in the NDRG1 promoter. Western blotting showed that nuclear AHR was up-regulated in the presence of cobalt and hypoxia. Immunofluorescence staining and chromatin immunoprecipitation assays showed that AHR translocated to nuclei and bound to NDRG1 promoter in hypoxia. Luciferase reporter assays further showed that the binding site of AHR at -412 ∼ -388 bp played a crucial role in regulating NDRG1 under hypoxia-mimicking conditions. Moreover, hypoxia-mimetic induction of NDRG1 by was attenuated by knockdown of AHR expression using short interfering RNA. Also, overexpression of AHR facilitated cell proliferation and migration via up-regulation of NDRG1, whereas shRNA knockdown of NDRG1 reduced cell growth and motility. In summary, these results showed for the first time that AHR positively regulates NDRG1 transcription through a AHR binding site by hypoxia-mimetic signaling, which may lead to development of a specific therapeutic regime to prevent tumor malignancy under hypoxia.

Citation Format: En-Yu Li, Wei-Yung Huang, Mong-Hsun Tsai, Eric Y. Chuang, Liang-Chuan Lai. Aryl hydrocarbon receptor activates NDRG1 transcription under hypoxia in breast cancer cells. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 1983. doi:10.1158/1538-7445.AM2015-1983
Abstract 1992: Evidence for modulation of FoxM1 by p21 in ovarian cancer
Authors: Madden Jill , Chien Jeremy
Published: August 2015

The oncogenic transcription factor forkhead box M1 (FoxM1) is overexpressed in many cancers, including 84% of ovarian cancer and plays a role in DNA repair, mitotic checkpoint, cell proliferation, and cancer drug resistance. Similar to Her2 in breast cancer, the constitutive expression of FoxM1 makes it a plausible gene target for novel anti-cancer therapies, but the regulation of FoxM1 has yet to be elucidated. Evidence suggests FoxM1 up-regulation is a result of TP53 mutations, however, no TP53 response element has been found within the FoxM1 promoter, thus there is likely another molecule mediating p53-induced FoxM1 overexpression. We hypothesize that cyclin-dependent kinase inhibitor 1a, p21, is involved in the regulation of FoxM1 by p53 in ovarian cancer. To test this hypothesis, we knocked down p21 expression with siRNA and shRNA in two wild-type p53 cancer cell lines, NCI-H23 and A2780. Knock down of p21 resulted in a mirrored increase in FoxM1 protein level in both cell lines as detected by Western blot. The addition of nutlin-3 (10 μM), a p53 stabilizer, to these p21 knocked down cell lines restored some p21 expression 24 hour post-treatment, which led to a subsequent decrease in FoxM1 levels compared to the corresponding DMSO-treated p21 knock down. These results suggest p21 is a negative regulator of FoxM1 in cancer cell lines. To further investigate this pathway, the same two cancer cell lines were treated with the FoxM1 inhibitor thiostrepton (10 μM) and protein levels were measured over a time course of 48 hours. FoxM1 protein levels were reduced following 8 hours, a time point where p21 protein levels peaked. This finding was further support by qRT-PCR analysis of A2780 ovarian cancer cell mRNA collected 0, 6, 8, 9, 10, 11, and 12 hours following thiostrepton (10 μM) treatment. In this experiment, p21 mRNA levels peaked 6 hours post-treatment, with FoxM1 mRNA levels reduced at 8 hours post-treatment, relative to control. Although thiostrepton has been shown to directly bind and inhibit the transcription of FoxM1, these results suggest that thiostrepton may also induce p21, potentiating FoxM1 inhibition. Thiostrepton has previously been shown to induce cancer cell death and reduce tumor burden, therefore further supporting FoxM1 as a potential drug target as well as encouraging the need to understand regulators involved in this pathway.

Citation Format: Jill Madden, Jeremy Chien. Evidence for modulation of FoxM1 by p21 in ovarian cancer. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 1992. doi:10.1158/1538-7445.AM2015-1992
Abstract 2001: Identification of lactate dehydrogenase A (LDHA) as a potential therapeutic target for prostate cancer radiotherapy
Authors: Hao Jingli , Graham Peter H. , Chang Lei , Ni Jie , Wasinger Valerie , Beretov Julia , Bucci Joseph , Cozzi Paul , Li Yong
Published: August 2015

Introduction: Radiation therapy (RT) is an important treatment option for prostate cancer (CaP) patients at both early and advanced-stage disease. Many CaP patients suffer from relapse and metastasis due to radio-resistance. In this study, we aimed to develop a radio-resistant CaP (CaP-RR) xenograft model, to identify potential protein markers associated with radio-resistance using proteomic approach, and to validate the identified biomarkers in CaP cell lines and animal xenografts.

Methods: Subcutaneous (s.c) CaP animal model was established using PC3-RR and PC3-control CaP cells in NODSCID mice. Tumor xenografts were harvested 5 weeks post cell inoculation and the proteins were extracted. Using LC-MS/MS expression protein profiles from the two groups were created. Statistical analysis was performed using one-way ANOVA for all features. Mascot was employed for peptide identification. Differential protein expressions were identified by re-importing the Mascot data to Progenesis software. The protein pathways and the top KEGG terms were searched against KEGG database using ingenuity software. Selected pathway markers or modulators were validated in CaP-RR cell lines and xenograft tumors using western blotting and immunohistochemistry, respectively. Lactate dehydrogenase A (LDHA) was selected for functional studies including radio-sensitivity, apoptosis and autophagy assays.

Results: We found for the first time that higher levels of vascularity, proliferation, and proteins from the glycolysis pathway are associated with CaP-RR xenograft tumors and that more than two hundred proteins were differentially expressed between CaP-RR and CaP naïve tumor xenografts. In addition, we demonstrated that the increased expressions of glycolysis markers, including LDHA, were certified in both CaP- CaP-RR cell lines and xenograft tumors. Knock-down or inhibition of LDHA combined with RT increase the radiosensitivity in PC3-RR cells, induce more apoptosis and autophagy compared to each single treatment alone.

Conclusions: We have successfully identified protein signatures using a CaP-RR xenograft animal model. The glycolysis pathway protein LDHA is a promising candidate to develop combination therapy to overcome CaP radioresistance.

Citation Format: Jingli Hao, Peter H. Graham, Lei Chang, Jie Ni, Valerie Wasinger, Julia Beretov, Joseph Bucci, Paul Cozzi, Yong Li. Identification of lactate dehydrogenase A (LDHA) as a potential therapeutic target for prostate cancer radiotherapy. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 2001. doi:10.1158/1538-7445.AM2015-2001
Abstract 2023: MYC amplification and overexpression in metastatic anaplastic thyroid cancer dictates response to therapy
Authors: Yilmaz Emrullah , Russo Marika A. , Orlacchio Arturo , Forde Toni , Di Cristofano Antonio
Published: August 2015

Anaplastic thyroid cancer (ATC) is a very aggressive and lethal cancer with few months of survival from diagnosis. Although less than 2% of all thyroid carcinomas are ATC, it accounts for up to 40% of thyroid carcinoma deaths. TRP53 inactivating mutations and PI3K activation through loss of PTEN, or PIK3CA mutations and amplification are common in ATC. In fact, targeted deletion of Pten and Trp53 in the mouse thyroid results in ATC development.

Using this mouse model, we found that Myc is amplified in 38% (11/29) of [Pten,Trp53]thyr-/− ATCs with distant metastasis, but only in 10% (3/30) non-metastatic ATCs. Conversely Myc was not amplified in any of 15 metastatic follicular thyroid carcinomas developed by Ptenthyr-/− mice. Analysis of human ATCs showed Myc amplification in 17% (3/18) tumors and protein overexpression in 25% of samples in a tissue microarray.

Myc amplification has been shown to be associated with resistance to PI3K targeted therapies in different tumor types. We evaluated the role of Myc in ATC growth and response to therapy using cell lines derived from our [Pten,p53]thyr-/− mouse model.

Myc-amplified cell lines grew faster than cell lines from tumors without Myc amplification both in full medium and under serum deprivation. Myc knockdown resulted in a dramatic decrease in growth rate, especially under serum starvations, suggesting that tumors with Myc amplification are less dependent on growth factors present in the serum. Myc knockdown in Myc-amplified cells completely impaired tumor formation in syngeneic mice.

To evaluate the effect of Myc amplification on drug sensitivity, we screened a panel of drugs on cultured cells. Myc knockdown sensitized ATC cells to PLK1 inhibition with BI6727, PI3K inhibition with BKM120, as well as to doxorubicin and etoposide. Conversely, Myc-amplified cells were more sensitive to carboplatin.

Our results show that Myc amplification is a biomarker for more aggressive and resistant ATCs and that MYC-targeting strategies could be employed to sensitize these tumors to conventional and targeted therapy.

Citation Format: Emrullah Yilmaz, Marika A. Russo, Arturo Orlacchio, Toni Forde, Antonio Di Cristofano. MYC amplification and overexpression in metastatic anaplastic thyroid cancer dictates response to therapy. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 2023. doi:10.1158/1538-7445.AM2015-2023
Abstract 2029: Mcph1/Brit1 deficiency promotes genomic instability and tumor formation in a mouse model
Authors: Liang Yulong , Gao Hong , Lin Shiaw-Yih , Goss John A. , Du Chunying , Li Kaiyi
Published: August 2015

MCPH1, also known as BRIT1, has recently been identified as a novel key regulatory gene of the DNA damage response pathway. MCPH1 is located on human chromosome 8p23.1, where human cancers frequently show loss of heterozygosity. As such, MCPH1 is aberrantly expressed in many malignancies, including breast and ovarian cancers, and the function of MCPH1 has been implicated in tumor suppression. However, it remains poorly understood whether MCPH1 deficiency leads to tumorigenesis. Here, we generated and studied both Mcph1−/− and Mcph1−/−p53−/− mice; we showed that Mcph1−/− mice developed tumors with long latency, and that primary lymphoma developed significantly earlier in Mcph1−/−p53−/− mice than in Mcph11+/+p53−/− and Mcph1+/−p53−/- mice. The Mcph1−/−p53−/− lymphomas and derived murine embryonic fibroblasts (MEFs) were both more sensitive to irradiation. Mcph1 deficiency resulted in remarkably increased chromosome and chromatid breaks in Mcph1−/−p53−/− lymphomas and MEFs, as determined by metaphase spread assay and spectral karyotyping analysis. Additionally, Mcph1 deficiency significantly enhanced aneuploidy as well as abnormal centrosome multiplication in Mcph1−/−p53−/− cells. Meanwhile, Mcph1 deficiency impaired double strand break (DSB) repair in Mcph1−/−p53−/− MEFs as demonstrated by neutral Comet assay. Compared with Mcph1+/+p53−/− MEFs, homologous recombination and non-homologous end joining activities were significantly decreased in Mcph1−/−p53−/− MEFs. Notably, reconstituted MCPH1 rescued the defects of DSB repair and alleviated chromosomal aberrations in Mcph1−/−p53−/- MEFs. Taken together, our data demonstrate MCPH1 deficiency promotes genomic instability and increases cancer susceptibility. Our study using knockout mouse models provides convincing genetic evidence that MCPH1 is a bona fide tumor suppressor gene. Its deficiency leading to defective DNA repair in tumors can be utilized to develop novel targeted cancer therapies in the future.

Citation Format: Yulong Liang, Hong Gao, Shiaw-Yih Lin, John A. Goss, Chunying Du, Kaiyi Li. Mcph1/Brit1 deficiency promotes genomic instability and tumor formation in a mouse model. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 2029. doi:10.1158/1538-7445.AM2015-2029
Abstract 203: Visualization of drug delivery by using high resolution microscopic mass spectrometry
Authors: Yasunaga Masahiro , Furuta Masaru , Ogata Koretsugu , Koga Yoshikatsu , Matsumura Yasuhiro
Published: August 2015

Pharmacokinetic (PK) and pharmacodynamic (PD) studies are important to evaluate the efficacy and toxicity of the drugs. In these analyses, tissue homogenates are generally used for the quantification by high-performance liquid chromatography (HPLC) or liquid chromatography mass spectrometry (LC-MS). However, they lack the information regarding the drug distribution in a specific anatomical area. The information of the drug distribution allows us to optimize the drug design enabling more efficient targeted delivery. We studied the tissue distribution of paclitaxel (PTX) and its micellar formulation (NK105) using a microscopic mass spectroscopy (MMS). A MMS in which a microscope is coupled with an atmospheric pressure matrix-assisted laser desorption/ionization (MALDI) and quadruple ion trap time-of-flight (TOF) analyser was used. The matrix-coated drug sample is ionised and then separated on the basis of its mass-to-charge ratio (m/z). Images were acquired from imaging mass spectrometry (IMS) or tandem mass spectrometry (MS/MS) data. (1) We established the drug imaging system with enhanced resolution and sensitivity. In the analysis, MS and MS/MS were used for quantification and validation, respectively. (2) NK105 showed much stronger antitumor effects on a human pancreatic cancer BxPC3 xenograft than PTX. In the drug imaging, we demonstrated that NK105 delivered more PTX to the whole tumor tissue (including the center lesion). In the mouse model, PTX caused the peripheral neurotoxicity but NK105 did not. Multiple high drug-signal areas surrounding and inside the caudal nerve were observed in the case of PTX, whereas the signals after NK105 injection were significantly low. We succeeded in visualising the EPR (Enhanced Permeability and Retention) effect using MMS. The data obtained by the drug imaging may be useful for facilitating DDS-drug design.

The significance of microscopic mass spectrometry with high resolution in the visualisation of drug distribution. Sci Rep. 3:3050. 2013.

Citation Format: Masahiro Yasunaga, Masaru Furuta, Koretsugu Ogata, Yoshikatsu Koga, Yasuhiro Matsumura. Visualization of drug delivery by using high resolution microscopic mass spectrometry. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 203. doi:10.1158/1538-7445.AM2015-203
Abstract 2042: Low Slit2 expression is associated with the aggressiveness of papillary thyroid carcinoma
Authors: Jeon MinJi , Kim Won Gu , Lim Seonhee , Jang Eun Kyung , Kim Tae Yong , Shong Young Kee , Kim Won Bae
Published: August 2015

Context: Slits, representative axon guidance molecules, and their Roundabout (Robo) transmembrane receptors are identified as key regulators of many cancers. One genome-wide liknage analysis suggested Slit-Robo Rho GTPase activating protein 1 gene as a candidate gene in papillary thyroid carcinoma (PTC) susceptibility.

Objective: To identify the role of Slit-Robo signaling in PTC.

Results : Slits(Slit 1-3) and Robos (Robo 1-4) were expressed in all of thyroid cancer cells and Slit2, Slit3, Robo1 and Robo4 presented higher expression than others. The mRNA expression of Slits and Robos was higher in fresh frozen PTC tissues than matched normal tissues. When we conducted immunohistochemical staining of Slit2 and Robo1 in thyroid tissues, the positivity of Slit2 and Robo1 were higher in PTC tissues than benign or normal tissues. However, negative Slit2 expression was significantly associated with cervical lymph node (LN) metastasis, distant metastasis and cervical recurrence of PTC (P <.001) irrespective of BRAF mutation status. In cellular assays, Slit2 treatment inhibited proliferation of thyroid cancer cells as dose dependent manner and also significantly suppressed cell migration by inhibiting activation of beta-catenin and inducing E-cadherin. Slit2 treatment also significantly suppressed beta-catenin activation induced by Wnt3A in luciferase reporter assay.

Conclusions : Low expression of Slit2 was associated with poor prognostic factors in PTC. This present study demonstrated the potential of Slit2 as a novel prognostic and therapeutic factor in PTC.

Citation Format: MinJi Jeon, Won Gu Kim, Seonhee Lim, Eun Kyung Jang, Tae Yong Kim, Young Kee Shong, Won Bae Kim. Low Slit2 expression is associated with the aggressiveness of papillary thyroid carcinoma. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 2042. doi:10.1158/1538-7445.AM2015-2042
Abstract 2049: Characterization of a novel BRCA1-EGR1 interaction
Authors: Dickson Naomi A. , Crawford Nyree T. , Mullan Paul B.
Published: August 2015

The tumor suppressor protein BRCA1 orchestrates DNA repair and cell cycle arrest following DNA damage, with transcriptional regulation integral to these processes. We have identified a novel, DNA-damage responsive, interaction between BRCA1 and the zinc-finger transcription factor EGR1. EGR1 is rapidly and transiently expressed in response to a wide variety of stress stimuli and growth factors, and like BRCA1, decreased expression of EGR1 correlates with tumor formation in mammary cell lines and tissues.

The stress response gene, NDRG1, was identified as a transcriptional target of BRCA1 by microarray analysis and subsequent RQ-PCR validation. NDRG1 is a known suppressor of breast cancer metastasis and we have observed a significant reduction of NDRG1 expression in breast cancer cell lines (relative to normal cell lines). Promoter analyses identified EGR1 binding motifs within the NDRG1 proximal promoter region, and EGR1 was confirmed as the transcription factor of interest by promoter assays. Downregulation of either BRCA1 or EGR1 (using a siRNA approach) resulted in a reduction in both basal and DNA-damage induced NDRG1 promoter activity, suggesting a co-regulatory mechanism. Indeed, recruitment of BRCA1 and EGR1 to the NDRG1 promoter was confirmed by ChIP assays.

GST-fused BRCA1 deletion constructs showed that EGR1 specifically interacts with a C-terminal region of BRCA1 (which contains both BRCT domains). However, following DNA damage, we observed EGR1 interaction along the entire length of the BRCA1 protein, suggesting that both BRCA1 and EGR1 reside within a larger transcriptional complex upon DNA damage. In agreement with this, siRNA knockdown of either BRCA1 or EGR1 in breast cell lines (i) induced endogenous DNA damage signalling, (ii) increased intracellular ROS generation and (iii) upregulated numerous stress-response genes.

To investigate transcriptional regulation downstream of this interaction we performed analyses of publically available ChIP-Seq data for both BRCA1 and EGR1, and identified a list of genomic locations (corresponding to gene promoters) at which both proteins localise. We will use these findings, in combination with our own ChIP-Seq experiments performed in the non-tumorigenic mammary cell line, 184A1, to investigate the roles of this novel complex in the maintenance of genomic stability and within normal breast biology.

Citation Format: Naomi A. Dickson, Nyree T. Crawford, Paul B. Mullan. Characterization of a novel BRCA1-EGR1 interaction. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 2049. doi:10.1158/1538-7445.AM2015-2049
Abstract 2058: RHOA inactivation enhances Wnt signaling and promotes colorectal cancer
Authors: Rodrigues Paulo , Macaya Irati , Bazzocco Sarah , Andretta Elena , Mazzolini Rocco , Dopeso Higinio , Mateo-Lozano Silvia , Bilic Josipa , Cartón-García Fernando , Nieto Rocio , Suárez-López Lucia , Afonso Elsa , Landolfi Stefania , Hernandez-Losa Javier , Kobayashi Kazuto , Ramón y Cajal Santiago , Tabernero Josep , Tebbutt Niall C. , Mariadason John M. , Schwartz Jr Simo , Arango Diego
Published: August 2015

Activation of the small GTPase RHOA has strong oncogenic effects in many tumor types, although its role in colorectal cancer remains unclear. We show that RHOA inactivation contributes to colorectal cancer progression/metastasis, largely through the activation of Wnt/β-catenin signaling. RhoA inactivation in the murine intestine accelerates the tumorigenic process and in human colon cancer cells leads to the redistribution of β-catenin from the membrane to the nucleus and enhanced Wnt/β-catenin signaling, resulting in increased proliferation, invasion and de-differentiation. In mice, RHOA inactivation contributes to colon cancer metastasis and reduced RHOA levels were observed at metastatic sites compared to primary human colon tumors. Therefore, we have identified a new mechanism of activation of Wnt/β-catenin signaling and characterized the role of RHOA as a novel gene with tumor suppressor activity in colorectal cancer. These results constitute a shift from the current paradigm and demonstrate that RHO GTPases can suppress tumor progression and metastasis.

Citation Format: Paulo Rodrigues, Irati Macaya, Sarah Bazzocco, Elena Andretta, Rocco Mazzolini, Higinio Dopeso, Silvia Mateo-Lozano, Josipa Bilic, Fernando Cartón-García, Rocio Nieto, Lucia Suárez-López, Elsa Afonso, Stefania Landolfi, Javier Hernandez-Losa, Kazuto Kobayashi, Santiago Ramón y Cajal, Josep Tabernero, Niall C. Tebbutt, John M. Mariadason, Simo Schwartz Jr, Diego Arango. RHOA inactivation enhances Wnt signaling and promotes colorectal cancer. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 2058. doi:10.1158/1538-7445.AM2015-2058
Abstract 2064: GSK3 regulation of Mcl1 and beta catenin involves I kappa B alpha
Authors: Thidil Puliyappadamba Vineshkumar , Thudi Nanda Kumar , Bredel Markus
Published: August 2015

Recently we demonstrated that the gene NFKBIA is deleted in most of the nonclassic sub types of Glioma. We have also shown that the over-expression of NFKBIA causes sensitization of the cancer cells towards various chemotherapeutic agents. We further extended our study to investigate the mechanism behind this chemo-sensitization by using temazolamide and and BAY 11-7082. We used two glioma cell lines U251, LN229 and one breast cancer cell line MDAMB231. Very interestingly we found that over expression of NFKBIA itself results in the down regulation of two major anti apoptotic proteins Mcl1 and Bcl-XL respectively. Next we treated the cells with Temozolamide and BAY 11-7082 separately and analysed the protein profile by western blotting. We have seen a strong down regulation of Mcl1 in all the cell lines and BCL-xl in two cell lines. But we didn't see any difference in the abundance of another related anti apoptotic protein Bcl2. We have seen enhanced apoptotic signal corresponding with the Mcl1 degradation. So it is clear from the study that the down regulation of Mcl1 by NFKBIA makes cells more susceptible towards the chemotherapeutic drugs.

Interestingly we also found that the protein beta-catetnine, a major component of a Wnt signaling pathway, is up regulated with the IκBα over expression and remain unchanged with the chemotherapeutic drugs in all the cell lines. Mcl1 degradation was mediated by the phosphorylation of GSK3 and the phosphorylated GSK3 prevent the usual proteasomal degradation of the beta-catetnine leading to it's accumulation in the cell. Thus we can conclude that NFKBIA paly an important role in the phosphorylation of GSK3 and results in the regulation of Mcl-1 and beta catenine.

Citation Format: Vineshkumar Thidil Puliyappadamba, Nanda Kumar Thudi, Markus Bredel. GSK3 regulation of Mcl1 and beta catenin involves I kappa B alpha. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 2064. doi:10.1158/1538-7445.AM2015-2064
Abstract 2069: Stromal-epithelial crosstalk of Mig-6 has an important role for tumor suppression via progesterone in endometrial cancer
Authors: Kim Tae Hoon , Kim Byung Gak , Yoo Jung-Yoon , Lee Jae Hee , Castrillon Diego H. , Jeong Jae-Wook
Published: August 2015

Endometrial cancer is the most common malignancy of the female genital tract. This disease is commonly caused by an imbalance of progesterone (P4) and estrogen (E2) action that E2 stimulates proliferation of uterine epithelial cells while P4 is inhibitory to estrogen-mediated proliferation of the epithelium. Endometrial hyperplasia is also associated with endometrial cancer, which is a proliferative process in epithelium by E2. Responsiveness of progesterone is required to treat endometrial cancer and preserve the fertility of patients. Furthermore, PR expression in the uteri of patients with endometrial cancer has been used as an indicator for a first-rate prognosis. However, more than 30% of patients do not respond to progesterone treatment as a result of progesterone resistance and the mechanism of progesterone resistance is still unknown. Thus, identifying the mechanism of progesterone in endometrial cancer is essential to improve the therapy of this disease. Mitogen-inducible gene 6 (Mig-6) is an important mediator of progesterone receptor (PR) action in the murine uterus. As P4 achieves the inhibition of proliferation by coordinating stromal-epithelial cross-talk, we generated a mouse model in which we specifically ablate epithelial endometrial Mig-6 using Sprr2f-cre mice (Sprr2fcre+ Mig-6f/f) to understand the role of epithelial Mig-6 in the uterus. Sprr2fcre+ Mig-6f/f mice displayed endometrial hyperplasia upon 10 weeks of age and develop endometrial cancer by E2 treatment for 3 months. Interestingly, the hyperplasia exhibited by Sprr2fcre+ Mig-6f/f mice was prevented by P4 treatment for 1 week in morphological and histological analysis. Proliferation decreased in the glandular epithelium of Sprr2fcre+ Mig-6f/f mice by P4, and apoptotic signal was also reduced. The expressions of stromal PR and its target genes were induced in Sprr2fcre+ Mig-6f/f mice after P4 treatment, indicating that P4-induced stromal Mig-6 can prevent the hyperplasia via regulating steroid hormonal signaling. This study suggested that stromal-epithelial communication of Mig-6 is critical in tumor suppressor function via regulating steroid hormonal signaling by progesterone. (This work was supported by American Cancer Society Research Grant, RSG-12-084-01-TBG to J.W.J.)

Citation Format: Tae Hoon Kim, Byung Gak Kim, Jung-Yoon Yoo, Jae Hee Lee, Diego H. Castrillon, Jae-Wook Jeong. Stromal-epithelial crosstalk of Mig-6 has an important role for tumor suppression via progesterone in endometrial cancer. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 2069. doi:10.1158/1538-7445.AM2015-2069