bluuebunny/crossref_metadata_2025_split huggingface dataset:
Abstract 4621: Rapamycin inhibits the phosphorylation of mSin1 by targeting a new mTOR complex
Authors: Huang Shile , Luo Yan , Liu Lei 
Published: July 2016

Abstract
Current knowledge indicates that mTOR functions as two complexes, mTORC1 and mTORC2, in mammalian cells. mTORC1 comprises mTOR, mLST8 and raptor, and is sensitive to acute rapamycin treatment, whereas mTORC2 consists of mTOR, mLST8, rictor, mSin1 and Protor, and is sensitive to chronic rapamycin treatment in some cases. It is well known that mTORC1 phosphorylates 4E-BP1 and S6K1, while mTORC2 phosphorylates Akt and SGK1. Recently, we and others have observed that rapamycin inhibits the phosphorylation of mSin1. However, little is known about the molecular mechanism by which rapamycin inhibits mSin1 phosphorylation. Here we show that rapamycin inhibits mSin1 phosphorylation in mTOR kinase dependent manner. This is strongly supported by the findings that expression of rapamycin-resistant mTOR (mTOR-T), but not rapamycin-resistant and kinase dead mTOR (mTOR-TE) prevented rapamycin from inhibiting mSin1 phosphorylation; Knockdown of mTOR inhibited mSin1 phosphorylation. However, surprisingly, disruption of either mTORC1 or mTORC2 (by silencing raptor and rictor, respectively) failed to inhibit the phosphorylation of mSin1 as rapamycin did. Similarly, downregulation of S6K1 or Akt did not inhibit mSin1 phosphorylation as rapamycin did either. Of interest, knockdown of mLST8, a component shared by mTORC1/2, inhibited mSin1 phosphorylation. Furthermore, rapamycin treatment reduced the physical interaction of mSin1 with mLST8 and mTOR, but not with rictor. The results suggest that rapamycin inhibits mSin1 phosphorylation, which is not by inhibiting mTORC1 or mTORC2, but via inhibiting a new mTOR complex, which contains at least mTOR and mLST8. (Supported by the FWCC, LSU Health Sciences Center)
Citation Format: Shile Huang, Yan Luo, Lei Liu. Rapamycin inhibits the phosphorylation of mSin1 by targeting a new mTOR complex. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4621.
Abstract 4640: Doxorubicin induced cardiomyopathy associated with natural reproductive hormone cycling in female tumor-bearing spontaneously hypertensive rats
Authors: Pokrzywinski Kaytee L. , Rosen Elliot T. , Bonnano Julia , Biel Thomas , Moshkelani Delaram , Aryal Baikuntha , Mog Steven , Rao V. Ashutosh 
Published: July 2016

Abstract
Doxorubicin (dox) is a widely used oncology agent known to induce dose-limiting cardiomyopathy, driven partially by the excess production of reactive oxygen species (ROS) in mitochondria. Cardiomyocytes are particularly sensitive to ROS due to higher densities of mitochondria and lower concentrations of antioxidants. The incidence of dox induced cardiomyopathy is lower in reproductively mature women compared to age matched men, while pre-pubescent and post-menopausal females are more sensitive. Previous studies have associated reproductive hormone levels with differences in cardiosensitivity based on gender and age. This is the second part of a two part study investigating the role that reproductive hormones play in dox induced cardiotoxicity in female, tumor-bearing spontaneously hypertensive rats (SHRs). In the current study, we investigated the impact of natural hormone cycling on dox induced cardiomyopathy. Before beginning the experiment, regular hormone cycling was established by monitoring daily changes in the estrous cycle by way of vaginal cytology. The animals were organized by phase (proestrus, estrus, metestrus, or diestrus) and implanted with SST-2 cells, a syngeneic breast cancer cell line derived from a SHR. Tumor-bearing animals were administered a single dose of saline, dox, the cardioprotectant dexrazoxane, or a combination thereof and monitored for 14 days. Daily vaginal cytologies were obtained throughout the experiment to monitor estrous cycling as a means of tracking hormone fluctuations. Serum was collected at various time points to correlate estrous cycling with circulating hormone levels (E2 and P4) and measure the cardiac health indicator cardiac troponin I (cTnI). In all hormone groups, dox treatment resulted in a net loss in bodyweight and significant anti-tumor activity, as measured by tumor volume, compared to respective saline controls. Interestingly, animals treated with saline in metestrus displayed increased tumor volumes compared to animals in different estrous phases. We are currently evaluating cardiac status by echocardiogram, histopathology, and cTnI. We are also measuring serum E2 and P4 hormone levels in an effort to understand the relationship between cardiomyopathy and circulating hormones.
Citation Format: Kaytee L. Pokrzywinski, Elliot T. Rosen, Julia Bonnano, Thomas Biel, Delaram Moshkelani, Baikuntha Aryal, Steven Mog, V. Ashutosh Rao. Doxorubicin induced cardiomyopathy associated with natural reproductive hormone cycling in female tumor-bearing spontaneously hypertensive rats. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4640.
Abstract 465: CD44 as a potential therapeutic target and prognosis marker for glioblastoma
Authors: Wang Fengfei , Shen Xin , Pruszynski Jessica , Huang Jason , Kirmani Batool , Wu Erxi , Fonkem Ekokobe 
Published: July 2016

Abstract
Glioblastoma (GBM) is a common and very aggressive primary brain tumor with no cure. The current diagnosis relying on magnetic resonance imagining, computed tomography, and biopsy is a very expensive and aggressive process. More effective therapeutic strategies such as target therapies and simplified early diagnosis tools are urgently needed for GBM management and prognosis. As recent reports suggest that GBM expresses CD44, a type-I transmembrane glycoprotein, is a marker of cancer stem cell and therapy resistance, with a goal of identifying a therapeutic target and a prognosis maker for GBM, we analyzed several data sets previously detected by microarrays using an online R2 Genomics analysis and visualization platform (http://r2.amc.nl). Through examining of the expression levels of CD44 in the tissues of normal cerebellum (without brain tumor) and in GBM tissues, we find that the expression level of CD44 in GBM is higher than that in non-brain tumor tissues. Comparing the expression levels of CD44 in Primary and recurrent GBMs, GBM cell lines, neuron stem cell lines, and normal cortex tissues, we observe that the expression levels of CD44 in recurrent GBMs are higher than primary GBMs; the CD44 levels in GBM cell lines are similar to neuron stem cell lines which are significantly higher than that in the normal cortex tissues. We further evaluated the correlation of CD44 levels with patients’ overall survival in 4 available complete data sets in the R2 database, including 2 from The Cancer Genome Atlas (TCGA) database. We show that an elevated level of CD44 in GBM is associated with a short overall survival time although variations exist from cohort to cohort. In addition, we studied the effect of p53 status on CD44 expression, we reveal that CD44 level is higher in the GBMs carrying p53 mutation compared to those with wild-type p53. Taken together, these results indicate that CD44 could be a potential therapeutic target of GBM and the expression level of CD44 in the GBM may be an indicator of poor outcome for patients with GBM.
Citation Format: Fengfei Wang, Xin Shen, Jessica Pruszynski, Jason Huang, Batool Kirmani, Erxi Wu, Ekokobe Fonkem. CD44 as a potential therapeutic target and prognosis marker for glioblastoma. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 465.
Abstract 4650: Effect of prescription CYP3A inducers and inhibitors on response to anti-androgen therapy in prostate cancer
Authors: Mitra Ranjana , Goodman Oscar B. 
Published: July 2016

Abstract
Purpose: Prostate cancer affects elderly men who typically have multiple comorbidities requiring concomitant prescription medications, many of which are CYP inducers or inhibitors. Androgen deprivation therapy (ADT) is the mainstay therapy for treating advanced prostate cancer. Recently we demonstrated that CYP3A5 facilitates the nuclear translocation of androgen receptor (AR), promoting prostate cancer growth. As the mechanisms by which intratumoral CYP3A5 regulates AR in prostate cancer are not well understood, the clinical impact of concomitant drugs on the efficacy of ADT is presently unknown. This work describes a platform for assessing the effects of commonly prescribed drugs known to be CYP3A5 inducers or inhibitors on AR signaling and prostate cancer growth.
Methods: We have created a lentiviral LNCaP based reporter system for monitoring changes in AR signaling utilizing a construct comprising a promotor containing AR inducible transcriptional response elements (TREs), fused with firefly luciferase, whereas the negative control (NC) lacks the TREs. We used both a mixed transfected pool and individually selected clones to monitor changes in AR activity.
Results: We tested our assay system by inhibiting CYP3A5 gene expression in LNCaP cells using siRNA and then treating it with DHT. Our data indicate that CYP3A5 siRNA reduced DHT induced AR activity significantly as compared to non-target (NT) siRNA. We further tested our reporter system with rifampicin, phenytoin (both CYP3A inducers) and ritonavir, fluoxetine, amiodarone (CYP3A inhibitors). Rifampicin (antibiotic) and phenytoin (anticonvulsant) showed significant (P≤0.05) induction of AR activity as shown by increased luminescence units. Out of the three inhibitors which were tested amiodarone (antiarrhythmic) and ritonavir (antiretroviral) reduced the AR activity by 50% and 80% respectively whereas fluoxetine (antidepressant) did not result in any significant changes. Both amiodarone and ritonavir also inhibited R1881 (artificial androgen) induced AR activity as compared to control.
Conclusion: Concomitant medications can alter the AR activity thus modifying the response to ADT therapy in prostate cancer patients. These finding support the notion that an CYP3A inhibitor-rich concomitant medical regimen may provide additional clinical benefit for men undergoing ADT and further support the concept of targeting nuclear translocation as a therapeutic adjunct in ADT.
Citation Format: Ranjana Mitra, Oscar B. Goodman Jr. Effect of prescription CYP3A inducers and inhibitors on response to anti-androgen therapy in prostate cancer. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4650.
Abstract 4658: Activation mechanisms of Integrated Stress Response by inhibition of oncogenic BRAF in melanoma cell lines
Authors: Nagasawa Ikuko , Tsukahara Satomi , Kunimasa Kazuhiro , Tomida Akihiro 
Published: July 2016

Abstract
The eIF2α-ATF4 signaling pathway termed “Integrated stress response (ISR)” plays an important role in protecting cells against various cellular stresses such as deprivation of glucose and amino acids, virus infection, and deficiency of heme. Under such stress conditions, eIF2α kinases, including PERK, GCN2, PKR and HRI, phosphorylate eIF2α, resulting in reduction of general protein synthesis while facilitating selective translation of ATF4, a central transcription factor that upregulates expression of stress-induced genes for cellular adaptation. Recently, it was reported that BRAF inhibitor vemurafenib triggers activation of the eIF2α-ATF4 signaling in BRAF-mutant melanoma cell lines; however, activation mechanisms of vemurafenib-induced ISR signaling not fully understood.
In this study, we first compared vemurafenib-induced ISR activation in BRAF-mutant and -wild type melanoma cell lines. Consistent with previous studies, vemurafenib activated ISR signaling preferentially in BRAF-mutant cell lines, as determined by phosphorylation of eIF2α and ATF4 expression. We also found that the ISR activation by vemurafenib was impaired by knockdown of BRAF in BRAF-mutant cell lines. These results indicated that existence of mutated BRAF is important for vemurafenib to trigger activation of ISR signaling pathway. We next examined which eIF2α kinase is involved in the ISR signaling activation by vemurafenib. We found that knockdown of GCN2, an eIF2α kinase sensing depletion of amino acids, impaired phosphorylation of eIF2α and ATF4 induction by vemurafenib. In addition, we confirmed that vemurafenib induced phosphorylation of GCN2 on Thr899 that is known to occur in response to amino acids starvation. In agreement with these results, gene expression profiling with ontology analysis revealed that vemurafenib upregulated genes that are involved in amino acids biosynthesis via ISR signaling. Collectively, our results suggested that vemurafenib activated ISR signaling pathway possibly through mimicking amino acid deprivation in BRAF-mutant melanoma cell lines.
Citation Format: Ikuko Nagasawa, Satomi Tsukahara, Kazuhiro Kunimasa, Akihiro Tomida. Activation mechanisms of Integrated Stress Response by inhibition of oncogenic BRAF in melanoma cell lines. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4658.
Abstract 467: Immunohistochemical multiplex staining strategies with CD8, CD103, PD-1, FOXP3 and pan melanoma cocktail in tumor infiltrating lymphocytes in melanoma
Authors: Tacha David E. , Yuan Wei , Terrell Jillian 
Published: July 2016

Abstract
Introduction
Tumor-associated immune suppression can lead to defective T-cell mediated antitumor immunity. CD8 T-cells play a critical role in the host defense against cancers and infectious diseases. However, the presence of antigen-specific CD8 T-cells does not always imply that cancers and/or pathogens are efficiently eliminated in the body. In tumor infiltrating lymphocytes (TILS), other markers including CD103, PD-1 and FOXP3 are broadly expressed and have shown a wider range of immunoregulatory and important roles in T-cell activation, T- cell regulatory and programmed cell-death checkpoints. Existing methods can either deliver phenotypic information on homogenous samples such as flow cell cytometry or give immunohistochemical information on single biomarker. However, it would be of advantage to be able to visualize the distributions of multiple biomarkers in TILs that would discriminate stromal cells versus solid tumor. Therefore, a multiplex IHC stain utilizing a melanoma marker as a staining mask that separates the malignant tumor cells from stromal cells maybe a good strategy to facilitate better interpretation.
Materials and Methods
Monoclonal mouse antibodies to CD8, FOXP3 and PD-1 and rabbit monoclonal antibodies CD8, CD103 and PD-1 were optimally tittered for single, double and triple stains and visualized with HRP DAB/Black chromogens and/or alkaline phosphatase fast red/blue chromogens. A mouse monoclonal pan melanoma cocktail was visualized with a fast red chromogen and was used as a staining mask for melanoma tumors cells, but not stromal cells.
Results
Single, double and triple stains that included pan melanoma cocktail (mask) and CD8, CD103 FOXP3 and PD-1 were successfully established. All double and triple stains gave comparable results to single stains. The co-expression of TILs including CD8 and CD103 or CD8 or FOXP3 and PD-1 was easily identified with contrasting chromogens. TILs in stroma tissues and in malignant tumors cells were easily discriminated with the pan melanoma (mask) that stained only tumor cells with fast red chromogen, but did not stain TILS or stromal tissues.
Conclusion
The evaluation of TILS in malignant melanoma was enhanced with multiplex stains. TILs in stromal tissues and melanoma tumors cells were easily distinguished with the Pan Melanoma staining mask. These finding may help facilitate important prognostic information and thus may support the rationale for using immunotherapy strategies.
Citation Format: David E. Tacha, Wei Yuan, Jillian Terrell. Immunohistochemical multiplex staining strategies with CD8, CD103, PD-1, FOXP3 and pan melanoma cocktail in tumor infiltrating lymphocytes in melanoma. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 467.
Abstract 4683: Verapamil and tamoxifen modulate ABCB1 expression in multidrug-resistant cells and resensitize them to conventional chemotherapy
Authors: Limniatis Georgia , Georges Elias 
Published: July 2016

Abstract
Multidrug-resistant (MDR) tumors are an increasingly important obstacle in cancer treatment, wherein many cases are associated with the overexpression of P-glycoprotein 1 (P-gp1, ABCB1). Previous efforts to sensitize ABCB1-expressing tumor cells to anti-cancer drugs were associated with severe side effects, so interest in clinical trials using these drugs has dwindled.
Studies have shown P-glycoprotein-overexpressing cells to be hyper sensitive (or collaterally sensitive) to a diverse group of non-toxic compounds. Given earlier results demonstrating a significant increase in ABCB1 expression post-chemotherapeutic treatment of cancer patients (e.g., breast, ovarian, myeloma, and acute myeloid leukemia), and the role of ABCB1 in drug resistance, it was determined that targeting ABCB1-expressing tumor cells with effective collateral sensitivity drugs should increase the effectiveness of current chemotherapeutic treatments.
In this report, it was of interest to determine the effect of the collateral sensitivity drugs verapamil and tamoxifen on P-glycoprotein 1 expression at the level of cells and individual cell clones. Clones from P-gp1-overexpressing Chinese hamster ovarian cell lines (CHRC5) or triple negative breast cancer cells (MDA-MB-231/400 nM doxo) were treated with varying levels of collateral sensitivity drugs and ABCB1 expression was determined by Western blots and ELISAs. The sensitivity of each cell clone to anti-cancer or collateral sensitivity drugs was determined using cytotoxicity assays.
Our results demonstrate a drop in ABCB1 expression in each clone, together with decreased collateral sensitivity and overall increased sensitivity to anti-cancer drugs in cell lines selected with verapamil and tamoxifen. Work is in progress to study the various mechanisms responsible for this drop in ABCB1 expression and its impact on treatment outcome.
Citation Format: Georgia Limniatis, Elias Georges. Verapamil and tamoxifen modulate ABCB1 expression in multidrug-resistant cells and resensitize them to conventional chemotherapy. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4683.
Abstract 4689: Successfully targeting triple negative breast cancer using combination therapy of Didox and Doxorubicin with reduced cardiotoxicity
Authors: Wilson Elizabeth A. , Elford Howard L. , Faridi Jesika S. 
Published: July 2016

Abstract
Triple-negative breast cancer (TNBC) is an aggressive histological subtype that has limited treatment options with chemotherapy being the only systemic therapy for these patients. The most common chemotherapy regimen used includes the anthracycline Doxorubicin (DOXO). Although DOXO is a highly effective agent, its efficacy is limited due to acquired drug resistance and cardiotoxicity. We have previously identified that ribonucleotide reductase M2 (RRM2) is upregulated in TNBC cells and is a key contributor to acquired drug resistance. The ribonucleotide reductase inhibitor Didox has been shown to be a powerful free radical scavenger and iron chelator that provides the capabilities to alleviate the cytotoxic profile of DOXO especially the cardiotoxicity as well as enhance the DOXO efficacy. In this current study, MDA-MB-468 and MDA-MB-231 TNBC cells were treated with DOXO alone or DOXO plus Didox. Synergy assays were performed and IC50 values were determined. Here we report that Didox worked synergistically with DOXO and reduced the DOXO IC50 values by more than one-half in each cell line. In order to determine the in vivo benefit of adding Didox to DOXO therapy, ncr-nude mice implanted with MDA-MB-468 xenografts were treated with (1) vehicle, (2) daily Didox alone (425 mg/kg), (3) DOXO alone (10 mg/kg/week for 2 doses and 2 mg/kg/week for 3 additional doses), or (4) the combination of DOXO and Didox. Tumor volumes over time were determined for each of the treatment groups. At endpoint, we performed necropsy, collected serum, and dried and weighed the hearts. Treatment with DOXO alone prevented tumor growth and provided about a 70% lower tumor volume as compared to vehicle treatment. Treatment with Didox alone yielded about 50% lower tumor volume as compared to vehicle treatment. However, adding Didox in combination with DOXO significantly inhibited the tumor size and resulted in a 90% lower final tumor volume as compared to vehicle treatment. One indicator of DOXO cardiotoxicity is increased heart weight. We found that the heart weight of DOXO alone treated animals was significantly increased and the inclusion of Didox in the treatment prevented this increase. Collectively, these results identify that adding the ribonucleotide reductase inhibitor Didox in combination with DOXO may be used to treat TNBC by enhancing the efficacy on tumor inhibition and by alleviating the cardiotoxic effects of DOXO.
Citation Format: Elizabeth A. Wilson, Howard L. Elford, Jesika S. Faridi. Successfully targeting triple negative breast cancer using combination therapy of Didox and Doxorubicin with reduced cardiotoxicity. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4689.