bluuebunny/crossref_metadata_2025_split huggingface dataset:
Abstract 2361: Pim kinase inhibition alters mRNA splicing in AML cell lines
Authors: Joglekar Tejashree A. , Li Xiang , Bieberich Charles J. 
Published: July 2017

Abstract
Oncogenic kinase activity is a common feature of nearly all cancers and kinases are major targets for therapeutic intervention. Pim kinases are deregulated in hematopoietic cancers including Acute Myeloid Leukemia (AML), as well as prostate cancer. While cancer cells can become dependent on Pim activity to sustain proliferation, in normal adult tissues, Pim kinase activity appears to be dispensable. These features make Pim kinases an attractive target for cancer therapy, however, their physiological roles have not been fully characterized. Using the reverse in-gel kinase assay (RIKA), we identified a battery of novel Pim substrates that are involved in mRNA splicing regulation. We hypothesized that Pim family kinases regulate mRNA splicing through phosphorylation of splicing factors. Microarray analysis revealed more than 10,000 splicing changes in AML cells treated with the highly selective small molecule Pim kinase inhibitor AZD1208. Using RT-PCR analysis, multiple AZD1208-induced splicing changes were validated. To discern the mechanisms whereby Pim kinases regulate splicing, we determined whether Pim inhibition alters phosphorylation of serine/arginine-rich (SR) proteins. Inhibition of serine arginine protein kinase (SRPK) activity using a small molecular inhibitor (SRPIN340) reduced SR protein phosphorylation, whereas Pim kinase inhibition did not, suggesting that Pim kinases regulate splicing through an SRPK independent pathway. Comparison of splicing changes in AZD1208 and SRPIN340 treated AML cells demonstrated distinct patterns, providing further evidence of SRPK-independent splicing regulation by Pim kinases. Biomarkers of kinase inhibitor efficacy are critical components of clinical trials. These data suggest that changes in mRNA splicing may serve as a biomarker for assessing patient responsiveness to Pim inhibition therapy.
Citation Format: Tejashree A. Joglekar, Xiang Li, Charles J. Bieberich. Pim kinase inhibition alters mRNA splicing in AML cell lines [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2361. doi:10.1158/1538-7445.AM2017-2361
Abstract 2365: Dual inhibition of the PI3k/Akt and MEK5/ERK5 pathways in tamoxifen resistant breast cancer
Authors: Wright Thomas D. , Hasan Mahmud , Witt-Enderby Paula , Cavanaugh Jane 
Published: July 2017

Abstract
Approximately 70% of breast cancers are considered estrogen receptor alpha (ER) and/or progesterone receptor (PR) positive, and their growth is primarily driven by the hormone estrogen. Initially these cancers are responsive to endocrine therapies such as tamoxifen. However, over time patients become resistant to conventional endocrine therapy and treatment becomes more difficult. Tamoxifen resistance occurs due to several mechanisms: loss of ER expression, gain of function mutations, pharmacological tolerance, alterations of co-activators, and ligand independent activation of ER by various kinase cascades. Aberrations in the Phosphoinositide-3-kinase (PI3K) and Mitogen Activated Protein Kinase (MAPK) pathways have been linked to increased breast cancer proliferation and survival. It has been proposed that these survival characteristics are enhanced through compensatory signaling and crosstalk mechanisms. The crosstalk between PI3K/Akt and MEK1/2/ERK1/2 has been characterized in several systems. However, new evidence suggests that MEK5/ERK5, a member of the MAPK family, is a key component in the proliferation and survival of therapy resistant cancers. MEK5/ERK5 has been shown to promote ER alpha driven transcription in ER+ breast cancers and actin reorganization and metastasis in ER- breast cancers. Furthermore, MEK5/ERK5 promotes hormone independent tumorigenesis in breast cancer. Our lab has previously investigated these pathways in hormone independent breast cancers, TNBC (triple negative breast cancer). Our previous results indicate that combinations of PI3k/Akt and MEK5/ERK5 blockade are promising because they inhibit both the pro-proliferative and pro-metastatic pathways in TNBC. Additionally, PI3k/Akt and MEK5/ERK5 inhibition was shown synergistically reduce viability in a diverse panel of cell lines (TNBC, ER+, and Triple Positive). Based on these initial results we hypothesize that PI3k/Akt and MEK5/ERK5 inhibition decreases viability via a hormone independent mechanism: perhaps by reducing the cytosolic sequestration of Bad. In this study we investigate the utility PI3k/Akt and MEK5/ERK5 inhibition in a MCF-7 TamR cell line. The goal of our study is to elucidate the roles of PI3k/Akt/mTOR and MEK5/ERK5 in endocrine resistant breast cancer and broaden the scope of a dual inhibition strategy.
Citation Format: Thomas D. Wright, Mahmud Hasan, Paula Witt-Enderby, Jane Cavanaugh. Dual inhibition of the PI3k/Akt and MEK5/ERK5 pathways in tamoxifen resistant breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2365. doi:10.1158/1538-7445.AM2017-2365
Abstract 2368: Differential role of Pik3caH1047R and Pten-/- mutations in thyroid cancer development
Authors: Ranieri Michela , Cristofano Antonio Di 
Published: July 2017

Abstract
Anaplastic thyroid cancer (ATC) is one of the most lethal malignancies, with a median survival of less than 6 months from time of diagnosis.
Molecular changes that characterize ATC involve most often p53 loss or inactivation (up to 80%), activation of the PI3K cascade through PTEN loss (12%) and PIK3CA activating mutations (20%) or gene amplification (30-60%), RAS family members activation (6-50%), and BRAF activation (25-50%).
Studies performed in endometrial and breast cancer suggest that although PI3K activating mutations and PTEN loss of function both enhance PI3K signaling, these mutations are not equivalent.
We have tested whether Pik3caH1047R and Pten-/- mutations have the same impact on thyroid cancer development and if these two mutations differ in their ability to cooperate with additional genetic alterations, such as p53 deletion and the KrasG12D activating mutation.
We have generated a series of mouse models and cell lines carrying thyroid-restricted p53-/-, KrasG12D, Pten-/-, and Pik3caH1047R alleles.
Analysis of single and compound mutants has revealed important and striking differences between Pten and PI3K abilities to control the PI3K signaling pathway.
Tumor development analysis in Pten-/- and Pik3caH1047R mice has revealed that Pik3ca activation is less potent in inducing thyroid hyperplasia and subsequent transformation than Pten loss, even though the two mutations appear to have similar ability to induce AKT activation. This differential activity correlates with lower levels of PIP3 found in the thyroids of Pik3caH1047R mice, compared to that of Pten-/- mice.
We also observed that while Pten loss synergizes with Trp53 loss to induce anaplastic thyroid cancer, activation of Pik3ca leads to the development of a smaller and well differentiated tumors.
On the other hand, Pten loss and Pik3ca activation are equivalent in inducing poorly differentiated tumors in the presence of a Kras activating mutation.
However, KrasG12D, Pik3caH1047R cell lines are more sensitive to PI3K, MEK and combined PI3K/MEK inhibition than KrasG12D, Pten-/- cell lines.
Accordingly, tumors developing in mice carrying the KrasG12D, Pik3caH1047R alleles are more sensitive than KrasG12D, Pten-/- mice to a dual PI3K/mTor inhibitor as well as a MEK inhibitor.
All together these results suggest that Pten loss has a stronger impact than Pik3ca activation to thyroid cancer development and resistance to small molecule inhibitors.
Citation Format: Michela Ranieri, Antonio Di Cristofano. Differential role of Pik3caH1047R and Pten-/- mutations in thyroid cancer development [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2368. doi:10.1158/1538-7445.AM2017-2368
Abstract 2370: Depletion of p21-activated kinase 4, PAK4, inhibits cellular proliferation, motility and clonogenicity in oral squamous cell carcinoma
Authors: Chung Felicia F. , Tan Si-Hoey , Raja Vijay J. , Ng Pei Yuen , Paterson Ian C. , Tan Chye Ling , Leong Chee-Onn 
Published: July 2017

Abstract
Oral squamous cell carcinoma (OSCC) accounts for 90% of all malignancies in the oral cavity, and is often associated with low survival and poor prognosis. While considerable progress in OSCC treatment has been made, options for targeted therapy remain limited. Thus, it is imperative that new druggable targets are identified and characterized. p21-activated kinase 4 (PAK4) is a member of the PAK family of serine/threonine kinases, which are known modulators of a diverse range of oncogenic pathways including cell proliferation, escape from apoptosis, and anchorage-independent growth. Previous reports have indicated that PAK4 is overexpressed in a subset of invasive OSCC, and is highly associated with poor prognosis. However, the specific role of PAK4 in OSCC has yet to be elucidated. Here, we show that RNAi-mediated depletion of PAK4 conferred reduced clonogenicity, cell motility, and cell proliferation in OSCC cell lines in a cell line-dependent manner. Global proteomic profiling of PAK4-depleted H103 and H357 cells was conducted to identify the molecules and signaling pathways responsive to PAK4 depletion. In addition to reported targets of PAK4 such as CFL1, ACTB, and TUBB6, we observed that p16INK4a, pre-mRNA splicing factors (SRSF2, SRSF5, SRSF6, SLU7), and proteasome activator subunits (PSME1-4) were dysregulated as a result of PAK4 depletion. These results indicate that PAK4 plays a role in promoting OSCC progression by regulating multiple signaling pathways. Of note, there have yet to be any reports describing interactions between PAK4 signaling and mRNA splicing or proteasome activation. Further investigation is thus warranted to further delineate the potential role of PAK4 in regulating these targets.
Citation Format: Felicia F. Chung, Si-Hoey Tan, Vijay J. Raja, Pei Yuen Ng, Ian C. Paterson, Chye Ling Tan, Chee-Onn Leong. Depletion of p21-activated kinase 4, PAK4, inhibits cellular proliferation, motility and clonogenicity in oral squamous cell carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2370. doi:10.1158/1538-7445.AM2017-2370
Abstract 2372: Xkr5 negatively regulates KIT/D816V signaling
Authors: Sun Jianmin , Thingholm Tine , Li Tianfeng , Kazi Julhash U. , Zhao Hui , Rönnstrand Lars 
Published: July 2017

Abstract
D816V is the most often occurred mutation of type III receptor tyrosine kinase KIT in mastocytosis and CBF-AML. In attempting to identify specific downstream signaling pathways of KIT/D816V, we found that KIT/D816V but not wild-type KIT can bind to Xkr5 that was not studied previously. In addition to the association with KIT/D816V, Xkr5 is phosphorylated at Tyr 369, Tyr487 and Tyr 543 by KIT/D816V, and the phosphorylation is mediated by only mutations of Asp 816 in KIT but not by other KIT mutations that occurred in gastrointestinal stromal tumors and melanoma. Furthermore, the tyrosine phosphorylation of Xkr5 is not dependent on Src family kinases that play a crucial role in the activation of wild-type KIT. In KIT/D816V expressing mast cells, phosphorylation of Xkr5 inhibits KIT/D816V downstream signaling molecules Akt, Erk and p38. As a consequence, cell proliferation and colony formation are inhibited by the tyrosine phosphorylation of Xkr5 as well, indicating that Xkr5 is a negative regulator of KIT/D816V signaling.
Citation Format: Jianmin Sun, Tine Thingholm, Tianfeng Li, Julhash U. Kazi, Hui Zhao, Lars Rönnstrand. Xkr5 negatively regulates KIT/D816V signaling [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2372. doi:10.1158/1538-7445.AM2017-2372
Abstract 2383: Nicotinamide N-methyltransferase inhibits Protein Phosphatase 2A activity by promoting Y307 phosphorylation
Authors: Jacob John R. , Chakravarti Arnab , Palanichamy Kamalakannan 
Published: July 2017

Abstract
Recent evidence indicates that suppression of protein phosphatase 2A (PP2A) activity plays an essential role in malignant transformation and cancer cell maintenance. Despite the importance of PP2A as a tumor suppressor in cancer, the mechanisms by which other enzymes regulate PP2A remain largely unknown. We recently identified Nicotinamide N-methyltransferase (NNMT) as a novel regulator of PP2A activity in glioblastoma (GBM). NNMT is a cytosolic N-methyl transferase which utilizes methyl groups from S-Adenosyl methionine (SAM), forming the by-product S-Adenosyl Homocysteine (SAH). PP2A becomes activated following the trimer formation of the three PP2A subunits, which requires the methylation of the catalytic subunit of PP2A (PP2A C) at L309.In cancer, NNMT has been reported to decrease the cellular methylation potential (SAM:SAH) and correspond with decreased PP2A activity. It was hypothesized that the decrease in methylation potential accounts for the decrease in PP2A activity by kinetically disfavoring the methylation of PP2A C. Interestingly, when we overexpressed NNMT in GBM cell lines and used LC-MS/MS (LC-MS Quadrupole Time-of-Flight and LC-MS Triple Quad) to monitor the methylation potential, we discovered that overexpression of NNMT increased methylation potential, however, still lead to a decrease in PP2A activity. As a result, we hypothesized that NNMT suppresses PP2A activity in a methylation-independent manner. In an effort to identify an alternative mechanism by which NNMT decreases PP2A activity, we found that NNMT expression was required for the phosphorylation of PP2A C at residue T307, which inhibits PP2A trimer formation and activation. Further, we found that NNMT expression leads to the constitutive activation of the PP2A target serine/threonine kinases (STKs): Akt, MAPK, and SAPK/JNK. NNMT silencing resulted in the deactivation of these STKs and radiation-induced cellular stress was not sufficient to rescue their activation. This suggests that NNMT-induced PP2A suppression is essential for the activation of these kinases. Overall, this study demonstrates a novel mechanism independent of methylation by which NNMT represses the activity of tumor suppressor PP2A.
Citation Format: John R. Jacob, Arnab Chakravarti, Kamalakannan Palanichamy. Nicotinamide N-methyltransferase inhibits Protein Phosphatase 2A activity by promoting Y307 phosphorylation [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2383. doi:10.1158/1538-7445.AM2017-2383
Abstract 2385: Systematic characterization of kinase inhibitors reveals heterogeneity in responses by class and cell line
Authors: Mills Caitlin E. , Hafner Marc , Juric Dejan , Sorger Peter K. 
Published: July 2017

Abstract
Several publications have addressed concerns surrounding drug response screens by pointing out sources of variability and by presenting recommendations for better experimental methods and more robust analytical approaches. In the presented profiling effort, we integrated the latest advances in drug response measurement and focused on data diversity and quality rather than on breadth. We selected 32 breast cancer cell lines with a strong bias towards triple negative lines as well as 4 cell lines established from relevant patient-derived xenografts. We evaluated a panel of clinically relevant kinase inhibitors using a microscopy-based drug response assay to measure drug potency, and to quantify drug efficacy in terms of growth inhibition (GR metrics) and cell death. The use of the GR metrics to quantify drug sensitivity enabled us to identify and study differences between cytostatic and cytotoxic responses. This systematic dose response dataset is complemented by measurements of baseline mRNA expression levels by RNAseq and endogenous protein levels by shotgun mass spectrometry across all cell lines. The completeness and controlled conditions under which these data sets were collected provide confidence in their integration. The baseline RNA and protein expression levels were used to build predictors of the measured drug responses with the goal of identifying the biological processes responsible for the differences in sensitivity across drugs and cell lines. Differences in the phenotypic responses of cell lines to kinase inhibitors with the same nominal targets have been investigated, and associated with variable inhibitor polypharmacology.
Citation Format: Caitlin E. Mills, Marc Hafner, Dejan Juric, Peter K. Sorger. Systematic characterization of kinase inhibitors reveals heterogeneity in responses by class and cell line [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2385. doi:10.1158/1538-7445.AM2017-2385
Abstract 2391: Integrated analysis of methylation and expression profile of telomere-related genes in breast cancer patients
Authors: Heng Jianfu , Guo Xinwu , Tang Lili , Zhang Fan , Peng Limin , Chen Ming , Luo Xipeng , Xu Xunxun , Wang Shouman , Wang Jun 
Published: July 2017

Abstract
Telomeres at the ends of chromosomes are critical in maintaining the integrity and stability of the genome. Aberrant telomere or telomerase dysfunction participates in tumorgenesis. A majority of human cancers exhibit critically aberrant telomere length, suggesting that tumors can arise from genetically instable cells with dysfunctional telomeres. Many genes are involved in the complex regulatory mechanisms of telomere length and telomerase activity. In addition, the methylation and expression pattern for most of telomere related genes in breast cancer are still unknown. Using microfluidic-PCR based target enrichment and next-generation bisulfite sequencing technology, we explored the promoter methylation profile of 29 telomere-related genes in 184 breast cancer patients with paired tumor and matched normal tissues. The average methylation level was significantly higher in tumor (8.13%) than that in matched normal tissues (7.08%) (P = 4.30E-21). Four genes showed significant hyper-methylation in the breast tumor tissues. All of these 4 genes are annotated with potential TFBSs in the promoter regions. In subtype analysis, RAD51D showed significant methylation difference among four subtypes. In analysis of the association between methylation and clinicopathologic characteristics, TERC showed significant difference between ER+/ER- tumors. The expression profile of the 4 significant hyper-methylated genes was explored in the same cohort using qPCR method. All of them showed significantly lower expression in breast tumor tissues compared with the matched normal tissues. Two genes showed significant and negative cis correlation between methylation and gene expression. These results were also validated in the TCGA database. The 4 genes panel showed a good performance in predicting breast cancer with ROC analysis. In summary, our results revealed the methylation pattern of telomere related genes in breast cancer and illustrated the epigenetic regulatory mechanism on expression of aberrant methylated genes. Our study provides a novel panel of telomere related genes which may be a valuable diagnostic biomarker for breast cancer prediction.
Note: This abstract was not presented at the meeting.
Citation Format: Jianfu Heng, Xinwu Guo, Lili Tang, Fan Zhang, Limin Peng, Ming Chen, Xipeng Luo, Xunxun Xu, Shouman Wang, Jun Wang. Integrated analysis of methylation and expression profile of telomere-related genes in breast cancer patients [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2391. doi:10.1158/1538-7445.AM2017-2391
Abstract 2394: Subpopulation of infiltrating lymphocyte and MGMT methylation in brain tumor prognosis
Authors: Castaneda Carlos , Castillo Miluska , Belmar-Lopez Carolina , Casavilca Sandro , Bernabe Luis Angel , Vidaurre Tatiana 
Published: July 2017

Abstract
Background: Clinicopathological features including MGMT methylation have been correlated to prognosis in Glioblastoma (GBM). Tumor infiltrating lymphocytes (TILs) are predictive of clinical outcome in different malignancies. We evaluated association between clinicopathological features including MGMT methylation and IHC infiltrating immune cell subpopulations in 43 resected GBM cases who came from 2008 to 2013.
Methods: A prospective evaluation of TIL (CD3, CD4, CD8 and CD20) and macrophages (CD68 and CD163) through H&E was performed by a pathologist and evaluated Immune cell subpopulations was evaluated through scanning, and software analysis (BX63 Olympus and TissueMorph-Visionpharm) with pathologist support. MGMT evaluation was prospectively performed by bisulphyte PCR test in paraffin samples.
Results: Median age was 47.9 y, men (51.2%), Karnofsky scale 90% (62.8%), median tumor size of 5.1 cm, and partial/ complete tumor resection (22/21). Methylation MGMT test was performed in 31 cases and 17 showed un- methylated, 4 partial methylated and 10 methylated. TILs evaluation by HE showed low- intensity (29 cases), middle- intensity (1) and high- intensity level (9). Pattern of distribution was focal (9 cases), multi- focal (13) and diffuse (17). Median CD3, CD4, CD8, CD20, CD68 and CD163 were 1.6%, 0.032%, 1.6%, 0.03%, 9.1% and 2.2% (regarding total cells), respectively. Higher CD163 level was associated to male (p=0.03) and larger size (p=0.05). Higher levels of CD8 was associated to larger size (p=0.05). Higher CD8 and CD20 was associated to unmethylated MGMT (p=0.041 and 0.013). Median follow- up was 14 months. Only total resection (p&lt;0.05) and MGMT methylation (p&lt;0.05) was associated to outcome. Lymphocyte infiltration (H&E) was not associated to outcome: Lymphocyte intensity (p=0.703), distribution (p=0.61). Longer OS was associated to lower CD4 levels (p=0.01).
Conclusion: Tumor Infiltrating immune cell are not common in GBM, CD8 and CD20 was associated to unmethylation, and CD4 and MGMT methylation were associated to prognosis.
Citation Format: Carlos Castaneda, Miluska Castillo, Carolina Belmar-Lopez, Sandro Casavilca, Luis Angel Bernabe, Tatiana Vidaurre. Subpopulation of infiltrating lymphocyte and MGMT methylation in brain tumor prognosis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2394. doi:10.1158/1538-7445.AM2017-2394