bluuebunny/crossref_metadata_2025_split huggingface dataset:
Abstract 2842: 5-aza-2’-Deoxycytidine induces cellular senescence in non-small cell lung cancer
Authors: Furukawa Masashi , Mimura Yuka , Tao Hiroyuki , Mimura Yusuke , Okabe Kazunori 
Published: July 2016

Abstract
Background: Lung cancer is one of the refractory malignancies and the leading cause of cancer-related death worldwide. Although prognosis of lung cancer was improved by the anticancer drugs and molecular targeted therapies, the results are not sufficient. Cellular senescence is irreversible cell cycle arrest. The drug-dependent induction of cellular senescence in neoplastic cells is considered an important tumor suppressive mechanism. 5-aza-2’-deoxycytidine (5-aza-dC) causes cellular senescence in solid tumors. Hypermethylation of CpG islands is well known as a major inactivation mechanism of tumor suppressor genes such as E-cadherin. Loss of E-cadherin confers a poor prognosis in lung cancer patients and is associated with in vitro resistance to epidermal growth factor receptor inhibitors. This study was designed to assess the relationship of E-cadherin expression cellular senescence induced by 5-aza-dC in non-small cell lung cancer (NSCLC) cell lines.
Materials and Methods: We investigated two NSCLC cell lines; H1299 and A549 reported they have hypermethylation in promoter lesion of E-cadherin. There are two clinically approved DNA methyltransferase inhibitors (DNMTi), 5-aza-dC and 5-azacytidine (5-aza-CR). We also used Sodium Butyrate (NaB). We treated them with each drug for 120 hours. Flow cytometry analysis, immunofluorescence staining for E-cadherin and senescence associated beta-galactosidase assays and immunoblotting for senescence related proteins assessed NSCLC cell outgrowth and morphology.
Results: Both cell lines with 5-aza-dC or NaB treatment changed morphology and increased size but decreased cell numbers. 5-aza-CR causes apoptosis in both cell lines. In A549, E-cadherin expression increased after 5-aza-dC treatment. There is no E-cadherin expression in H1299 with or without treatment. Both cell lines with 5-aza-dC were positive for Senescence-associated beta-galactosidase staining, H3K9me3 and gamma-H2AX.
Conclusion: Taking together these findings strongly suggest the ability of 5-aza-dC to induce cellular senescence in NSCLC cells. The cellular senescence induced by a 5-aza-dC approach has to be considered a therapeutic option for NSCLC and an important phenomenon to further investigate in the next future.
Citation Format: Masashi Furukawa, Yuka Mimura, Hiroyuki Tao, Yusuke Mimura, Kazunori Okabe. 5-aza-2’-Deoxycytidine induces cellular senescence in non-small cell lung 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 2842.
Abstract 2843: TASC1, a selective anti-senescence therapeutic which potently and selectively counteract resistance to chemo- and radiotherapy
Authors: Baar Marjolein P. , Putavet Diana A. , Pothof Joris , Hoeijmakers Jan H.J. , de Keizer. Peter L.J. 
Published: July 2016

Abstract
Resistance to therapy is a major limitation towards the cure of irresectable cancer.
Cellular senescence, induced by chemotherapy and radiotherapy, can drive therapy resistance in vivo. Senescence is a tumor suppressive mechanism, but senescent cells can secrete a range of proteins that ironically promote tumor growth, migration and metastazation and therapy resistance. Recent evidence has shown that genetic removal of senescent cells indeed causes a strong reduction in tumor growth and metastasis formation. Unfortunately however, therapeutic options to remove senescent cells are currently lacking.
Here, we show the development and optimization of a biochemical compound, TASC1, that potently and selectively kills senescent cells in vitro and in vivo and lowers organ toxicity in a mouse model employed to address the off-target effects of cancer therapy. This encouraged us to test the effect of TASC1 against cancer therapy resistance. We focused on Glioblastoma multiforme (GBM), the most aggressive and lethal stage of glioma (III-IV) with a median survival of less than 15 months. Treatment of GBM involves a combination of surgery, radiotherapy and adjuvant chemotherapy (Temozolomide). Response to radiotherapy is generally strong, but resistance occurs rapidly, after which currently no successful follow-up treatment exists. We observed radiation therapy to induce senescence in astrocytes and senescence-like effects in GBM cells, without affecting their progression.
Strikingly, while both TASC1 and radiation at various doses independently failed to reduce growth of these GBM cells, the combination of TASC1 with radiation showed a potent synthetic lethal response. Similar effects were seen for other types of cancer and their respective therapies. Thus, TASC1 is a potent adjuvant to (re)sensitize therapy-resistance metastatic cancer cells to treatment.
Citation Format: Marjolein P. Baar, Diana A. Putavet, Joris Pothof, Jan H.J. Hoeijmakers, Peter L.J. de Keizer. TASC1, a selective anti-senescence therapeutic which potently and selectively counteract resistance to chemo- and radiotherapy. [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 2843.
Abstract 2846: Proliferative recovery after chemotherapy-induced senescence in non-small cell lung cancer (NSCLC) cells as a model of tumor dormancy and disease recurrence
Authors: Saleh Tareq , Thekkudan Theresa , Alotaibi Moureq R. , Gewirtz David A. 
Published: July 2016

Abstract
Lung cancer is the leading cause of cancer-related death in both men and women in the United States. Most lung cancer cases are diagnosed in advanced, inoperable stages and are treated with chemoradiation; while chemoradiation is effective in suppressing tumor progression, recurrence following treatment is not infrequent. As there is no well-accepted preclinical model for tumor dormancy and disease recurrence, we hypothesize that the promotion of transient autophagy and senescence could be developed as a model of tumor growth and recovery following treatment. Studies were performed utilizing H460 NSCLC cells as well as a primary NSCLC cell line isolated and grown in our laboratory from a stage IV adenocarcinoma. After treatment with etoposide (1 uM), growth arrest was accompanied by the robust induction of autophagy and senescence. This growth arrest was transient and was followed by proliferative recovery in the course of several days. Genetic and pharmacological inhibition of autophagy failed to interfere with the ability of the cells to regrow, indicating a non-cytoprotective function of autophagy in response to etoposide (in contrast to the cytoprotective function of autophagy exhibited in response to radiation). Quantification of senescence over time based on C12FDG staining and flow cytometry demonstrated that the reversal of growth arrest coincided with a decline in the extent of senescence. To more precisely define the source of the recovered cells, senescent and non-senescent but growth arrested cells were separated by flow cytometry based on their relative β-galactosidase expression and replated. Both cell populations demonstrated the ability to re-emerge from the growth-arrested state and recover proliferative capacity. These observations suggest that senescence is ultimately a transient process in that at least a subpopulation of tumor cells can and will recover proliferative capacity. Furthermore, the reversibility of therapy-induced senescence (TIS) might prove to be a useful model both in cell culture and in vivo to study tumor dormancy and disease recurrence. Studies are currently in progress to determine the impact of senescence inhibition on tumor recovery as well as sensitivity to subsequent therapy given that recurrent disease tends to be relatively refractory to further treatment.
Citation Format: Tareq Saleh, Theresa Thekkudan, Moureq R. Alotaibi, David A. Gewirtz. Proliferative recovery after chemotherapy-induced senescence in non-small cell lung cancer (NSCLC) cells as a model of tumor dormancy and disease recurrence. [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 2846.
Abstract 2848: Autophagy, senescence and proliferative recovery subsequent to DNA damage in radiation sensitization by PARP inhibition
Authors: Alotaibi Moureq R. , Sharma Khushboo , Saleh Tareq , Povirk Lawrence , Hendrickson Eric , Gewirtz David 
Published: July 2016

Abstract
Radiotherapy continues to be a primary modality in the treatment of cancer. DNA damage induced by radiation can promote apoptosis as well as both autophagy and senescence, where autophagy and senescence can theoretically function to prolong tumor survival. A primary aim of this work was to investigate the hypothesis that autophagy and/or senescence could be permissive for DNA repair, thereby facilitating tumor cell recovery from radiation-induced growth arrest and/or cell death. In addition, studies were designed to elucidate the involvement of autophagy and senescence in radiation sensitization by PARP inhibitors and the re-emergence of a proliferating tumor cell population. In the context of this work, the relationship between radiation-induced autophagy and senescence was also determined. Studies were performed using DNA repair proficient HCT116 colon carcinoma cells and a repair deficient Ligase IV (-/-) isogenic cell line. Irradiation promoted a parallel induction of autophagy and senescence that was strongly correlated with the extent of persistent H2AX phosphorylation in both cell lines; however inhibition of autophagy failed to suppress senescence, indicating that the two responses were dissociable. Irradiation resulted in a transient arrest in the HCT116 cells while arrest was prolonged in the Ligase IV (-/-) cells; however, both cell lines ultimately recovered proliferative function, which may reflect maintenance of DNA repair capacity. The PARP inhibitors (Olaparib) and (Niraparib) increased the extent of persistent DNA damage induced by radiation as well as the extent of both autophagy and senescence; neither cell line underwent significant apoptosis by radiation alone or in the presence of the PARP inhibitors. Inhibition of autophagy failed to attenuate radiation sensitization, indicating that autophagy was not involved in the action of the PARP inhibitors. As with radiation alone, despite sensitization by PARP inhibition, proliferative recovery was evident within a period of 10-20 days. While inhibition of DNA repair via PARP inhibition may initially sensitize tumor cells to radiation via the promotion of senescence, this strategy does not appear to interfere with proliferative recovery, which could ultimately contribute to disease recurrence.
Citation Format: Moureq R. Alotaibi, Khushboo Sharma, Tareq Saleh, Lawrence Povirk, Eric Hendrickson, David Gewirtz. Autophagy, senescence and proliferative recovery subsequent to DNA damage in radiation sensitization by PARP inhibition. [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 2848.
Abstract 2849: RNA-binding protein FXR1 negatively regulates senescence by destabilizing mRNA CDKN1A and stabilizing noncoding RNA telomerase RNA component
Authors: Majumder Mrinmoyee , Palanisamy Nallasivam , Qie Shuo , Day Terry , Diehl Alan J. , Palanisamy Viswanathan 
Published: July 2016

Abstract
RNA-binding proteins (RBPs) regulate numerous aspects of co- and post-transcriptional gene expression. RBP fragile X-related protein 1 (FXR1) belongs to a family of RNA-binding proteins that includes functionally similar Fragile X mental retardation 1 (FMR1) and Fragile X-related 2 (FXR2). FMR1 is significantly studied in Fragile X Syndrome (FXS) where the gene is non-functional due to mutation or aberrant methylation. FXR1 protein is highly expressed in multiple cancers including lung and oral cancers. Here, we demonstrate that RBP FXR1 plays an essential role in the growth of head and neck squamous cell carcinomas (HNSCC) by blocking cellular senescence. FXR1 MEF cells were stained positive for senescence associated beta-galactosidase straining. We report a major function of FXR1 as it promotes the stability of Telomerase RNA Component (TERC), a non-coding RNA and simultaneously destabilizes CDKN1A mRNA, and blocks cellular senescence. FXR1-deficient HNSCC cells show an increase in different cyclin dependent kinase inhibitors (p21, p27), a decrease in p-AKT, and these cells also undergo a G0/G1 cell cycle arrest which are the early onsets of cellular senescence. FXR1 binds and stabilizes TERC RNA for telomere maintenance. On the contrary, FXR1 binds and destabilizes CDKN1A mRNA. By an independent assay we also show that the senescence phenomenon was only observed by a combined up and downregulation of CDKN1A and TERC, respectively which was only obtained by FXR1 knockdown. Thus, FXR1 forms a molecular link between CDKN1A and TERC for cell cycle control and telomere length, respectively, to repress cellular senescence in HNSCC.
Citation Format: Mrinmoyee Majumder, Nallasivam Palanisamy, Shuo Qie, Terry Day, Alan J. Diehl, Viswanathan Palanisamy. RNA-binding protein FXR1 negatively regulates senescence by destabilizing mRNA CDKN1A and stabilizing noncoding RNA telomerase RNA component. [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 2849.
Abstract 2857: The yeast homolog of the mammalian oncogene, Bax Inhibitor-1, regulates the unfolded protein response by altering the ER microenvironment
Authors: Benko Savannah , Brown Melissa , McCarthy Morgan , Sanborn Matthew , Cavedon William , Ritzer Lukas , Berry B. Michael , Austriaco Nicanor 
Published: July 2016

Abstract
Bax inhibitor-1 (BI-1) is an anti-apoptotic gene whose expression is upregulated in a wide range of human cancers. The yeast homolog of BI-1, yeast Bax inhibitor-1 (BXI1), encodes a protein that belongs to the Bax Inhibitor (TMBIM) family of proteins. The crystal structure of a prokaryotic member of the family, BsYetJ, has revealed that the Bax inhibitor proteins are pH sensitive calcium leaks. Our studies have shown that yeast Bxi1p is localized to the ER and is involved in the unfolded protein response (UPR) that is triggered by ER stress. We have recently found that Bxi1p regulates the UPR downstream of endonuclease Ire1p clustering but upstream of HAC1 mRNA splicing. Studies with an ER localized calcium reporter and an ER redox reporter suggest that Bxi1p accomplishes this by altering the ER microenvironment. [Our laboratory is supported by grant NIGMS R15 GM110578, awarded to N. Austriaco.]
Citation Format: Savannah Benko, Melissa Brown, Morgan McCarthy, Matthew Sanborn, William Cavedon, Lukas Ritzer, B. Michael Berry, Nicanor Austriaco. The yeast homolog of the mammalian oncogene, Bax Inhibitor-1, regulates the unfolded protein response by altering the ER microenvironment. [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 2857.
Abstract 2860: Loss of expression of the metastasis suppressor CREB3L1 is associated with high-grade metastatic breast cancer and poorer prognosis
Authors: Mellor Paul , Ward Alison , Anderson Deborah 
Published: July 2016

Abstract
The unfolded protein response (UPR) is required for proper protein folding in the endoplasmic reticulum under conditions of stress such as those encountered in the tumor microenvironment. Recently, a number of studies have suggested a role for the unfolded protein response in the development of cancer, more specifically in regulating the balance between cell death, dormancy and the growth of cancer cells in the tumor microenvironment. This study examined the role of CREB3L1 (cAMP-responsive element-binding protein 3-like protein 1), a member of the UPR, in breast cancer development and metastasis.
Initial experiments identified the loss of CREB3L1 expression in metastatic breast cancer cell lines compared to low- or non-metastatic cell lines. When metastatic cells were transfected with CREB3L1 they demonstrated reduced invasion and migration in vitro, as well as a significantly decreased ability to survive under non-adherent or hypoxic conditions. Interestingly, in an in vivo rat mammary tumor model, CREB3L1 expressing cells not only failed to form metastases compared to CREB3L1 null cells but regression of the primary tumors was seen in 70% of the animals as a result of impaired angiogenesis. Microarray and ChIP on Chip analyses identified changes in the expression of many genes involved in cancer development and metastasis, including a decrease in those involved in angiogenesis.
To determine if these findings translated to human breast cancer, real-time PCR analysis of CREB3L1 expression in human breast cancer tissues of differing grade (n = 213) was performed. Expression of CREB3L1 was elevated in low and medium grade tissue but substantially reduced in high grade tissue, compared to normal. Analysis of the on-line TCGA database of breast cancer samples identified a strong inverse relationship between CREB3L1 gene methylation and the loss of CREB3L1 mRNA expression. Low expression of CREB3L1 was associated with a poorer prognosis with a shorter relapse-free survival for luminal A and triple negative breast cancer patients.
These data suggest that CREB3L1 plays an important role in suppressing tumorgenesis and loss of expression is required for the development of a metastatic phenotype. In addition CREB3L1 expression may be a useful marker for determining patient prognosis.
Citation Format: Paul Mellor, Alison Ward, Deborah Anderson. Loss of expression of the metastasis suppressor CREB3L1 is associated with high-grade metastatic breast cancer and poorer prognosis. [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 2860.
Abstract 2862: The balance of divergent IRE1α signaling regulates pancreatic neuroendocrine tumor growth
Authors: Qi Jenny Y. , Moore Paul C. , Thamsen Maike , Ghosh Rajarshi , Gliedt Micah J. , Maly Dustin J. , Backes Bradley J. , Papa Feroz R. , Oakes Scott A. 
Published: July 2016

Abstract
The Unfolded Protein Response (UPR) is an intracellular signaling pathway that communicates the protein folding status of the endoplasmic reticulum (ER) to the nucleus to maintain ER homeostasis. Hypoxia, nutrient deprivation, proteasome dysfunction, or sustained demands on the secretory pathway–conditions often encountered by solid tumor cells–lead to the accumulation of misfolded proteins in the ER and cause “ER stress.” However, the precise role of UPR signaling in the development and maintenance of cancer remains controversial. We reasoned that pancreatic neuroendocrine tumors (PanNETs) might be one class of solid tumor that may be particularly sensitive to protein folding stress due to their high secretory activity.
The Master UPR regulator IRE1α is an ER transmembrane kinase/endoribonuclease (RNase) that acts as a critical life-death switch depending on the level of ER stress. We analyzed primary human PanNET samples for activation of UPR components and found strong evidence of ER stress and IRE1α hyperactivation in this tumor type. We used a variety of chemical-genetic tools to selectively manipulate IRE1α's homeostatic and apoptotic outputs in a PanNET xenograft model and found that the precise balance of IRE1α signaling is critical for tumor growth in vivo. Disrupting this balance by pushing the pathway in either direction is detrimental to PanNET survival. Moreover, targeting IRE1α with highly selective small molecules in a preclinical mouse model phenocopied the results of genetic manipulation. Our results indicate that IRE1α is an important regulator of PanNET cell survival and growth, and provide a strong rationale for therapeutically targeting this kinase in PanNETs and other cancers that experience high levels of ER stress.
Citation Format: Jenny Y. Qi, Paul C. Moore, Maike Thamsen, Rajarshi Ghosh, Micah J. Gliedt, Dustin J. Maly, Bradley J. Backes, Feroz R. Papa, Scott A. Oakes. The balance of divergent IRE1α signaling regulates pancreatic neuroendocrine tumor growth. [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 2862.
Abstract 2864: Role of ribosomal protein, Rpl22 in regulation of acute lymphoblastic leukemia
Authors: Solanki-Patel Nehal R. , Greenberg Noa , Rao Shu , Peri Suraj , Slifker Michael , Mullighan Charles , Wiest David 
Published: July 2016

Abstract
Inactivation of ribosomal proteins (RP) is known to cause diseases called ribosomopathies, which are often associated with abnormal hematopoiesis and an increased risk for development of leukemia. Our laboratory has recently reported an important link between inactivation of one such ribosomal protein, Rpl22, and poor survival in T cell acute lymphoblastic leukemia (T-ALL) patients. Preliminary bioinformatic analysis shows that RPL22 is lost in ∼10% of pediatric T-ALL patients, who exhibit a more aggressive disease course. Deletion of the RPL22 locus is also enriched in the early T-cell precursor (ETP-ALL) subset of T-ALL patients, which exhibit a more aggressive disease course. Thus, RPL22 loss appears to be a marker for poor outcome in pediatric T-ALL patients. While RP inactivation has previously been linked to increased cancer risk, the mechanistic basis for this linkage remained unclear. We have recently demonstrated that inactivation of Rpl22 promotes leukemic transformation by activating NF-κB and inducing the stem cell gene, LIN28B. Nevertheless, the molecular link between Rpl22 inactivation and the induction of NF-κB activity remained unclear. We have now determined that inactivation of Rpl22 activates NF-κB signaling by exacerbating ER stress responses. Indeed, Rpl22 loss results in hyperactivation of the PERK-EIF2α-ATF4 stress pathway, which is known to activate NF-κB. We have demonstrated that knockdown of PERK using shRNA abrogates the activation of NF-κB in Rpl22 mutant cells and returns Lin28B expression levels to baseline. This reduction in Lin28B eliminates the predisposition to transformation exhibited by Rpl22 mutant cells, as evidenced by decreased formation of colonies in soft agar. Taken together, these data suggest that RPL22 inactivation may serve as a negative prognostic indicator in T-ALL and that pharmacologic targeting of ER stress pathways may represent a novel therapeutic alternative in this molecularly-defined subclass of T-ALL.
Citation Format: Nehal R. Solanki-Patel, Noa Greenberg, Shu Rao, Suraj Peri, Michael Slifker, Charles Mullighan, David Wiest. Role of ribosomal protein, Rpl22 in regulation of acute lymphoblastic leukemia. [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 2864.