bluuebunny/crossref_metadata_2025_split huggingface dataset:
Abstract 4313: Protein synthesis modulates paraptotic death induced by inhibition of cyclophilins in glioblastoma (GBM) cells
Authors: Wang Lin , Gundelach Justin , Bram Richard 
Published: July 2017

Abstract
In this study, we investigated the mechanisms underlying cell death induced by the small molecule cyclophilin inhibitor NIM811. NIM811 effectively killed GBM cells through a non-apoptotic pathway, as there was no nuclear shrinkage or caspase activation. Instead, death was preceded by dramatic cytosolic vacuolization, stemming from enlargement of the endoplasmic reticulum (ER). RNA-seq revealed upregulation of genes pertinent to the unfolded protein response (UPR) and autophagy. Western blotting for UPR and autophagy mediators also supported a transient UPR signaling and compromised autophagy during prolonged NIM811 treatment. By utilizing a bicistronic reporter plasmid, we independently quantitated Cap-dependent and Cap-independent translation. We further assessed the long-term effects mediated by different short-term paraptosis inhibitors via colony formation assay. We find that NIM811 initiates paraptosis in GBM cells, due to an abnormal upregulation of protein translation that caused accumulation of misfolded or unfolded proteins in ER. Transient activation of pro-survival autophagy and UPR signals were shutdown during prolonged treatment with NIM811, thus allowing cell death to occur. Cycloheximide was previously reported by others to suppress paraptosis. In our studies, we find instead that it temporarily delayed vacuole formation, but actually enhanced paraptotic cell death in the long term. The mTOR inhibitors rapamycin or torin-2 rescued cells from NIM811 induced paraptosis by sustaining autophagy and the UPR, and specifically restrained cap-dependent translation. We propose that ER vacuolization could be a protective response generated by cells to isolate defective proteins within the ER in order to prevent misfolded aggregates to interfere with cellular homeostasis. For that reason, simply inhibiting vacuole formation without clearing protein accumulation in the ER was insufficient to prevent cell death. These findings aid our understanding of cellular mechanisms that contribute to non-apopotic death. Moreover, this work underlines the importance of evaluating cellular responses in cell death experiments over multiple time frames to judge the true impact.
Citation Format: Lin Wang, Justin Gundelach, Richard Bram. Protein synthesis modulates paraptotic death induced by inhibition of cyclophilins in glioblastoma (GBM) cells [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 4313. doi:10.1158/1538-7445.AM2017-4313
Abstract 4314: Exclusive delivery of mazF in cancer cells by Listeria monocytogenes
Authors: Saffarian Maryam , Tzeng Jeremy 
Published: July 2017

Abstract
Programmed cell death (PCD), an active process that leads to cell suicide, is a critical mechanism in every organism. MazF, a bacterial ribonuclease protein, can trigger PCD in bacterial cells and also induce Bak-dependent apoptosis in mammalian cells. This bacterial ribonuclease cleaves mRNAs at ACA sequences leading to inhibition of protein synthesis in cells. Hence, we hypothesized that the overexpression of MazF proteins in cancer cells could result in the induction of apoptosis. In the present study, the ACA-less mazF gene was inserted downstream of the Internal Ribosome Entry Site (IRES) and under the control of T7 promoter. The plasmid was electroporated into Listeria monocytogenes harboring pCSA1 that encodes T7 RNA polymerase under the control of the listeria actA promoter. Subsequently, the bacteria were functionalized with Trastuzumab (Herceptin®) to deliver the mazF mRNA into HER2/neu breast cancer cells. The results showed that MazF protein has an ability to induce apoptosis in HER2/neu breast cancer cells. This finding is the first report of the application and delivery of MazF as an anti-cancer agent for the induction of apoptosis in HER2/neu breast cancer cell line. This research suggests cancer therapy that targets only cancer cells but not healthy cells and offers more advantages, e.g., inexpensiveness, target tissue specificity, easy and safe delivery, in comparison to other gene therapy vectors or direct protein administration.
Citation Format: Maryam Saffarian, Jeremy Tzeng. Exclusive delivery of mazF in cancer cells by Listeria monocytogenes [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 4314. doi:10.1158/1538-7445.AM2017-4314
Abstract 4315: PTBP1 modulation of MCL1 mRNA regulates sensitivity to antitubulin chemotherapeutics
Authors: Placzek William J. , Cui Jia 
Published: July 2017

Abstract
Background: Myeloid Cell Leukemia 1 (MCL1), an anti-apoptotic Bcl-2 family protein, is a key regulator of intrinsic apoptosis. Normal cells require strict control over MCL1 expression and aberrant MCL1 expression has been shown linked to the emergence of various diseases and chemoresistance. Previous studies have detailed how MCL1 expression is regulated by multiple mechanisms both transcriptionally and translationally. However, characterization of the post-transcriptional regulators of MCL1 mRNA is limited. Polypyrimidine tract binding protein 1 (PTBP1) is a known regulator of post-transcriptional gene expression that can control mRNA splicing, translation, stability, and localization. In the described study we characterize the impact that PTBP1 has on MCL1 expression, its molecular mechanisms, and its roles on cellular apoptosis.
Methods: Cross-linking Immunoprecipitation (CLIP)-seq data analysis and RNA immunoprecipitation (RIP) were performed to analyze protein interactions with RNA and map the RNA binding sites on the genes of interests. RNA half-life was measured by treating cells with Actinomycin D and extracting total RNA at different time point. Cell viability was measured by the MTS assay and apoptosis was assessed by Annexin V/Propidium Iodide (PI) staining followed by flow cytometry analysis.
Results: Our studies demonstrate that PTBP1 binds to MCL1 mRNA and that knockdown of PTBP1 up-regulates MCL1 expression in cancer. Mechanistically, PTBP1 silencing stabilizes MCL1 mRNA and increases MCL1 mRNA accumulation in cytoplasm. We further identify that this post-transcriptional regulation is mediated by microRNAs and Argonaute2 (Ago2). Moreover, we show that PTBP1 down-regulation is anti-apoptotic to antitubulin chemotherapeutics in a MCL1-dependent manner.
Conclusions: Our findings suggest that PTBP1 is a novel post-transcriptional regulator of MCL1 mRNA by which it controls apoptotic response to antitubulin chemotherapeutics.
Note: This abstract was not presented at the meeting.
Citation Format: William J. Placzek, Jia Cui. PTBP1 modulation of MCL1 mRNA regulates sensitivity to antitubulin chemotherapeutics [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 4315. doi:10.1158/1538-7445.AM2017-4315
Abstract 4319: Analysis of Bcl-2 family members and protein-protein interactions using novel multiplex immunoassays
Authors: Maheshwari Reeti , Schluter Melissa , Pepin Danielle , Hwang Joseph 
Published: July 2017

Abstract
Bcl-2 family members play a very important role in intrinsic apoptotic pathways. The family consists of more than 17 members that can be functionally separated into pro-apoptotic and anti-apoptotic subfamilies. Interactions between these family members determine cell fate, and dysregulation can lead to tumor growth and tumor cell survival. There are several investigational drugs for cancer treatment targeting Bcl-2 family members in clinical trials, driving the need for robust assays to measure Bcl-2 family members and their interactions. Though existing assays measure Bcl-2 family members, there is a lack of reliable assays to evaluate total proteins and protein-protein interactions simultaneously. To address this issue, we have developed two Luminex®-based multiplex immunoassay panels that allow for the simultaneous detection of multiple components of the Bcl-2 family in a single well, including Total Bcl-2, Bcl-xL, Mcl-1, BAD, BIM, and BAX as well as protein interactions like NOXA/Mcl-1, Mcl-1/BIM, and Bcl-xL/BAD. Using these panels, we analyzed changes in the expression and interactions of Bcl-2 family members in response to known apoptotic drugs, including Camptothecin (topoisomerase inhibitor), Anisomycin (protein translation inhibitor), and AT101 (BH3 mimetic drug). Camptothecin and Anisomycin each elicited a significant decrease in the levels of Mcl-1. Additionally, the Mcl-1/BIM interaction was disrupted by both Camptothecin and Anisomycin, perhaps a consequence of the reduced Mcl-1 levels. However, expression of the other anti-apoptotic proteins was unaffected by any of the three drugs. Interestingly, all three treatments had different effects on the Mcl-1/NOXA interaction. Mcl-1/NOXA signal was increased by AT101, decreased by Anisomycin, and showed a dose dependent effect with Camptothecin. In contrast to their disparate effects on the Mcl-1/NOXA interaction, all three drugs acted in a similar manner in blocking the Bcl-xL/BAD interaction without affecting the total levels of either protein. Overall, these results illustrate the dynamic responses of the Bcl-2 family to apoptosis-inducing drugs. The novel multiplex immunoassays described here provide a powerful tool for studying the underlying mechanisms regulating the Bcl-2 family of proteins.
Citation Format: Reeti Maheshwari, Melissa Schluter, Danielle Pepin, Joseph Hwang. Analysis of Bcl-2 family members and protein-protein interactions using novel multiplex immunoassays [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 4319. doi:10.1158/1538-7445.AM2017-4319
Abstract 432: xCT inhibition disrupts redox homeostasis in CD44v-expressing tumor cells showing glutaminolytic metabolism in head and neck squamous cell carcinoma
Authors: Okazaki Shogo , Tsuchihashi Kenji , Sampetrean Oltea , Saya Hideyuki , Nagano Osamu 
Published: July 2017

Abstract
Metabolic changes favoring aerobic glycolysis and glutaminolysis may influence the sensitivity of tumor cells to anticancer drugs. We previously showed that sulfasalazine, an inhibitor of xCT-dependent cystine transport, selectively induces oxidative damage in undifferentiated tumor cells that express CD44 variant (CD44v) at a high level, without affecting CD44v-negative differentiated tumor cells, in head and neck squamous cell carcinoma (HNSCC). However, whether metabolic changes contribute to the xCT dependency of CD44v-expressing HNSCC cells has remained unknown. Here we show that CD44v-expressing HNSCC cells manifest a highly glutaminolytic phenotype and constitutively generate reactive oxygen species through glutamine metabolism pathway, and that xCT plays a key role in maintaining redox homeostasis in these cells. Inhibition of xCT suppressed the consumption of glutamine without affecting that of glucose in these cells, indicating that CD44v-expressing HNSCC cells also rely on xCT for maintenance of glutaminolysis. Furthermore, administration of sulfasalazine, but not that of the anticancer drug cisplatin, selectively depleted CD44v-expressing undifferentiated tumor cells positive for the glutamine transporter ASCT2 in human HNSCC tumors formed in nude mice. Targeting of xCT is thus a potential therapeutic approach for ASCT2-expressing HNSCC tumors in which cellular metabolism is shifted toward enhanced glutaminolysis.
Citation Format: Shogo Okazaki, Kenji Tsuchihashi, Oltea Sampetrean, Hideyuki Saya, Osamu Nagano. xCT inhibition disrupts redox homeostasis in CD44v-expressing tumor cells showing glutaminolytic metabolism in head and neck 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 432. doi:10.1158/1538-7445.AM2017-432
Abstract 4320: The Survivin-targeting miR-542-3p overcomes erbB3 signaling-mediated chemo-resistance and enhances the antitumor activity of paclitaxel against erbB2-positive breast cancer
Authors: Lyu Hui , Wang Shuiliang , Huang Jingcao , Wang Bolun , Liu Bolin 
Published: July 2017

Abstract
Elevated expression of erbB3 interacts with erbB2 in breast cancer cells to confer chemo-resistance via induction of Survivin. However, the underlying mechanism of erbB3 signaling-induced upregulation of Survivin remains elusive. Ectopic expression or downregulation of erbB3 in erbB2-positive breast cancer cells did not alter Survivin mRNA levels and had no significant effect on Survivin protein stability. We thus hypothesize that the erbB3 signaling modulates certain miRNAs that target Survivin to influence its protein translation. Here we showed that overexpression of erbB3 decreased and specific knockdown of erbB3 enhanced expression of two Survivin-targeting miRNAs, miR-203 and miR-542-3p in breast cancer cells. While the specific inhibitor of either miR-203 or miR-542-3p clearly attenuated an anti-erbB3 antibody (Ab)-mediated reduction of Survivin, a more profound effect on Survivin expression was observed with inhibition of miR-542-3p than miR-203 inhibition. Consistently, miR-542-3p mimic was much more effective than miR-203 mimic not only to downregulate Survivin, but also to enhance paclitaxel-induced apoptosis in the otherwise paclitaxel-resistant breast cancer cells. Moreover, using a murine tumor xenografts model established from a human breast cancer cell line expressing both erbB2 and erbB3, we discovered that the combinations of miR-542-3p mimic and paclitaxel, as compared to either agent alone, significantly inhibited tumor growth in vivo. Collectively, these data demonstrate that the erbB3 signaling upregulates Survivin via inhibition of miR-203 and miR-542-3p in erbB2-positive breast cancer cells. Since miR-542-3p has three binding sites on the 3’UTR of erbB3 mRNA, the miR-542-3p mimic serves as an excellent replacement therapeutic agent to downregulate Survivin, and thereby significantly enhances the antitumor activity of paclitaxel against erbB2-positive breast cancer.
Citation Format: Hui Lyu, Shuiliang Wang, Jingcao Huang, Bolun Wang, Bolin Liu. The Survivin-targeting miR-542-3p overcomes erbB3 signaling-mediated chemo-resistance and enhances the antitumor activity of paclitaxel against erbB2-positive 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 4320. doi:10.1158/1538-7445.AM2017-4320
Abstract 4333: The role of cancer-associated fibroblast-induced chemokine ligand 11 in tumor microenvironment contributes to the progression of oral cancer
Authors: Nieh Shin 
Published: July 2017

Abstract
Oral squamous cell carcinoma (OSCC) is one of the leading causes of cancer-related death in Taiwan and worldwide. The prognosis of OSCC is usually poor because of its propensity of extensive invasion, local recurrence and frequent regional lymph node metastasis, even at initial diagnosis. Recent studies showed carcinoma-associated fibroblasts (CAFs), a major type of tumor-surrounding stromal cell, generate certain mediators through which CAFs interact with tumors and contribute to cancer progression in numerous cancers. The orchestration between CAFs and cancer cells is complex and its underlying mechanism needs to be explored. In the present study, we used organotypic culture to investigate CAFs that promote aggressive behavior of cancer cells. Using microarray analysis, we detected abundant expression of chemokine (C-C motif) ligand 11(CCL11), also named Eotaxin, secreted by CAFs and further be identified as a critical mediator in CAF-induced invasiveness. We planned to validate that CCL11 played a major role in the crosstalk between fibroblasts and OSCC cells via the paracrine manner. CCL11was found upregulated in CAFs than in normal fibroblasts via Western blot analysis. Cells lines of OSCC, Fadu and TW204, treated with recombinant CCL11 increased capabilities of sphere formation in ten days. Administration of CCL11 promoted migration and invasion abilities through induction of the epithelial-to-mesenchymal transdifferentiation with corresponding morphological alterations of cancer cells. Counteracting CCL11 activity diminished the aggressive phenotype of cancer cells induced by CAFs. We further studied the relationship between the expression of CCL11 in both CAFs and OSCC cells and clinical outcome in the patients with OSCC. As a result, a high CCL11 expression level was associated with poor prognosis in terms of nodal metastasis and survival. These results indicate that CAFs promote cancer invasiveness via a paracrine effect on microenvironmental CCL11 signaling and suggest that CCL11 is a potential prognostic biomarker that may be considered in therapeutic strategies for the treatment of patients with OSCC.
Citation Format: Shin Nieh. The role of cancer-associated fibroblast-induced chemokine ligand 11 in tumor microenvironment contributes to the progression of oral 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 4333. doi:10.1158/1538-7445.AM2017-4333
Abstract 4341: Mesenchymal stem cells promote epithelial-mesenchymal transition of colon cancer cells via direct cell-to-cell contact
Authors: Takigawa Hidehiko , Kitadai Yasuhiko , Kuwai Toshio , Yuge Ryo , Tanaka Shinji , Chayama Kazuaki 
Published: July 2017

Abstract
We previously reported that in an orthotopic nude mouse model of human colon cancer, bone marrow-derived mesenchymal stem cells (MSCs) migrated to tumor stroma and promoted tumor growth and metastasis. We evaluated the proliferation and migration ability in directly and indirectly co-culture assay to clarify the mechanism of interaction between cancer cells and MSCs. Proliferation and migration ability of cancer cells were increased by direct co-culture with MSCs but not by indirect co-culture of MSCs. Thus, we thought that direct contact between cancer cells and MSCs is important to their interaction. We performed microarray analysis of gene expression in KM12SM colon cancer cells directly co-cultured with MSCs. Expression of epithelial-mesenchymal transition (EMT) related genes such as fibronectin (FN), SPARC and Galectin 1 was increased by direct co-culture with MSCs. We also confirmed the upregulation of these genes with real time PCR, and these genes were not increased in cancer cells indirectly co-cultured with MSCs. Among these EMT related genes upregulated by direct co-culture with MSCs, we examined immune localization of FN, well-known EMT marker. In co-culture assay in chamber slides, expression of FN in cancer cluster was seen only at the edge where cancer cells directly contacted with MSCs. FN expression by cancer cells was increased at the tumor periphery and invasive edge in orthotopic nude mice tumors and human colon cancer tissues, respectively. These results suggest that mesenchymal stem cells induce epithelial-mesenchymal transition of colon cancer cells via direct cell-to-cell contact and may play an important role of colon cancer metastasis.
Citation Format: Hidehiko Takigawa, Yasuhiko Kitadai, Toshio Kuwai, Ryo Yuge, Shinji Tanaka, Kazuaki Chayama. Mesenchymal stem cells promote epithelial-mesenchymal transition of colon cancer cells via direct cell-to-cell contact [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 4341. doi:10.1158/1538-7445.AM2017-4341
Abstract 435: Regulation of macropinocytosis-dependent cell survival in pancreatic cancer cells
Authors: Kim Sung Eun , Wang Man-Tzu , McCormick Frank 
Published: July 2017

Abstract
Cancer cells utilize multiple scavenging mechanisms to support growth in nutrient-poor, hypoxic environments. Signaling pathways to accommodate these mechanisms may not be required for oncogenesis per se but are crucial for cancer cell survival. These processes, known as non-oncogene addiction, can be conferred by specific oncogenes that reprogram metabolism or by the tumor microenvironment. Understanding how these pathways are regulated can provide novel opportunities for therapeutic intervention.
Studies showed that KRAS-mutant cancer cells, including pancreatic ductal adenocarcinoma (PDAC), upregulate macropinocytosis, a caveolin- and clathrin-independent endocytic process, to import extracellular protein to support growth upon nutrient depletion. Similarly, high levels of macropinocytic uptake are observed in PDAC murine models and also in human PDAC specimens. This process serves as a scavenging mechanism for cancer cells to survive and proliferate in nutrient-deprived tumor microenvironments. Thus, uncovering the key players of this pathway and the mechanisms underlying their regulation will be important to find potential therapeutic targets.
Here, we used the Informer set of small molecules to screen regulators of survival in culture conditions supplemented with either glutamine or extracellular protein. The Informer set drug library consists of small molecules including FDA-approved drugs and clinical candidates that have high selectivity for their targets and regulate many cellular pathways. We find that survival of cells grown in conditions supplemented with glutamine or exogenous protein is differentially regulated by distinct drug subsets. This suggests that different pathways of nutrient uptake, processing, and utilization are used in cells depending on the nutrient source. Further examination to determine the mechanism of pathway inhibition and applicability may unravel potential uses for therapeutics.
Citation Format: Sung Eun Kim, Man-Tzu Wang, Frank McCormick. Regulation of macropinocytosis-dependent cell survival in pancreatic cancer cells [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 435. doi:10.1158/1538-7445.AM2017-435