bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 1880: Bulk lung cancer cell migration is more common than single cell migration and regulated by different genes
Authors: Popper Helmut H. , Eidenhammer Sylvia
Published: July 2017

Introduction: There are two different forms how tumor cells migrate: single cell or small cell cluster movement as it is seen in small cell carcinoma, and movement by large clusters of organized cells as seen most often in adenocarcinoma or squamous cell carcinoma. This latter migration form is not understood. Drosophila border cells forming wings migrate in large cell complexes similar to what is seen in the carcinomas and the genes identified in these cells might regulate the same process in carcinomas. Methods: 30 cases of pulmonary squamous cell and adenocarcinomas were selected based on the identification of large tumor cell clusters visible within the stroma as well as in blood vessels. Immunohistochemistry was done for receptor of activated C kinase (Rack1), brinker (brk), mother against dpp (mad), and saxophone (sax), proteins shown to be responsible for bulk cell movement in drosophila development. In addition immunohistochemistry was also done for Src-kinase, Twist, Snail, and TGFβ1 Tyrosine kinase substrate 5 (Tks5), E-cadherin, SARI (suppressor of AP-1), and vimentin, all known to be associated with epithelial-to-mesenchymal transition (EMT) and formation of invadopodia. Results and Conclusion: Most well differentiated pulmonary carcinomas migrate in large cell clusters, for example acinar adenocarcinomas form nicely structured acini deep within the stroma and even within blood vessels. These carcinomas do not undergo classical EMT. Proteins expressed by the four genes (Rack1, brk, mad, and sax) associated with border cell movement in drosophila could also be identified in pulmonary carcinomas and might coordinate bulk cell movement. Other members of TGF-beta signaling cascade were identified. Inhibition of Src by Rack1 may be important for border cell migration and cluster cohesion maintenance. Proteins usually seen in single tumor cell migration, such as vimentin (a sign of EMT) could not be proven in the tumor cell clusters. Findings of this study show that similar mechanisms are working in pulmonary carcinomas and that bulk cell migration is probably another way of metastasis. Further investigation using cell culture system and genetically designed adenocarcinomas expressing these genes should prove our findings and contribute in understanding migration of carcinoma bulk complexes.

Citation Format: Helmut H. Popper, Sylvia Eidenhammer. Bulk lung cancer cell migration is more common than single cell migration and regulated by different genes [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 1880. doi:10.1158/1538-7445.AM2017-1880
Abstract 1882: Tankyrase-binding protein TNKS1BP1 regulates cancer cell invasion
Authors: Ohishi Tomokazu , Yoshida Haruka , Katori Masamichi , Migita Toshiro , Muramatsu Yukiko , Miyake Mao , Ishikawa Yuichi , Saiura Akio , Iemura Shun-ichiro , Natsume Tohru , Seimiya Hiroyuki
Published: July 2017

Tankyrase, a member of poly(ADP-ribose) polymerase (PARP) family, catalyzes addition of long PAR chains onto the acceptor proteins, such as TRF1, a telomere-binding protein, and Axin, a repressor of Wnt/β-catenin signaling. Tankyrase-mediated PARylation of TRF1 and Axin represses the biological functions of these proteins, leading to enhanced telomere elongation by telomerase and upregulation of Wnt/β-catenin signaling, respectively. Thus, tankyrase is a multifunctional protein that supports oncogenic properties of cancer cells. Given that tankyrase has a large protein-protein interaction platform called ANK repeat clusters, and is broadly distributed to various intracellular loci, including telomeres, nucleoplasm, nuclear pore complexes, cytoplasm, Golgi, and spindle poles, this protein seems to have a yet unidentified function. In the present study, we explored the function of a novel tankyrase-binding protein called TNKS1BP1 and elucidated its contribution to regulating cancer cell invasion. Since TNKS1BP1 co-localizes with the actin filaments, we first examined the effect of genetic manipulation of TNKS1BP1 expression on cell invasion. We found that TNKS1BP1 depletion by small interfering RNAs increased the invasive capacity of human fibrosarcoma cells, whereas its overexpression decreased the cell invasion. In TNKS1BP1-depleted cells, actin filament dynamics, focal adhesion and lamellipodia ruffling were increased with activation of the ROCK-LIMK-cofilin pathway, which promotes cell motility. Importantly, tankyrase overexpression reproduced the phenotype of TNKS1BP1-depleted cells and enhanced cell invasion in a PARP activity-dependent manner. Under approval by Institutional Review Board of Japanese Foundation for Cancer Research, we performed immunohistochemical analysis of clinical pancreatic cancer. We found that TNKS1BP1 protein expression is decreased in invasive regions of the tumors. Taken together, these observations suggest that the tankyrase-TNKS1BP1 axis constitutes a post-translational modulator of cell invasion and its aberration promotes cancer malignancy.

Citation Format: Tomokazu Ohishi, Haruka Yoshida, Masamichi Katori, Toshiro Migita, Yukiko Muramatsu, Mao Miyake, Yuichi Ishikawa, Akio Saiura, Shun-ichiro Iemura, Tohru Natsume, Hiroyuki Seimiya. Tankyrase-binding protein TNKS1BP1 regulates cancer cell invasion [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 1882. doi:10.1158/1538-7445.AM2017-1882
Abstract 1887: Untethering heterochromatin: how loss of HP1a enhances cell invasion by altering nuclear envelope integrity
Authors: Hale Tracy K. , Bond Sarah , Wheeler David
Published: July 2017

Malignant cell invasion is accompanied by complex changes in nuclear shape and organisation. The onset of invasion correlates with the loss of HP1a in many solid tumours including those of the thyroid, kidney, colon and breast, while in cancer cell lines HP1a suppresses invasive potential. In normal cells HP1a maintains the condensation of transcriptionally silent heterochromatin and sequesters it at the inner periphery of the nuclear envelope; an event critical for the maintenance of nuclear stability and envelope rigidity. This role for HP1a leads us to hypothesise that the un-tethering of heterochromatin from the nuclear periphery that would occur after loss of HP1 causes a remodelling of nuclear envelope that enhances cellular invasion. If true this would explain how the nucleus, the largest and most rigid cellular organelles, becomes malleable enough to squeeze through interstitial spaces in the surrounding tissue during metastatic invasion. In support of this hypothesis we observed a 44% increase in the invasive potential of the poorly invasive MCF7 breast cells when HP1a is knocked down. Lamin A staining and electron microscopy also confirmed that these HP1a knockdown cells had the expected alterations in nuclear morphology and loss of heterochromatin at the nuclear periphery. Furthermore the loss of HP1 was correlated with a decrease in the mechanical stability of the nuclei. The significant enrichment (p-val 6.7x10-8) of nuclear envelope proteins shown by RNAseq analysis of transcripts that are differentially expressed in the MCF7 versus HP1a knock-down cells, suggests this loss of nuclear envelope integrity is associated with alterations to its composition. The most striking change identified in the nuclear envelope of cells lacking HP1a was the loss of two Nesprin1 isoforms. While reintroduction of HP1a in highly invasive MDA-MB-231 cells shows the return of these isoforms to the nuclear envelope. As the Nesprin1 isoforms act as signalling scaffolds connecting to the cytoskeleton or reaching into the nucleus, they represent a means of modulating nuclear malleability. Together these findings suggest that when loss of HP1a increases invasive potential there is a corresponding disruption to the nuclear periphery that is a weakness of these cells that could be exploited.

Citation Format: Tracy K. Hale, Sarah Bond, David Wheeler. Untethering heterochromatin: how loss of HP1a enhances cell invasion by altering nuclear envelope integrity [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 1887. doi:10.1158/1538-7445.AM2017-1887
Abstract 1888: 3D matrix confinement triggers vascular mimicry through a conserved migratory and transcriptional response
Authors: Ortiz Daniel , Tsui Brian , Goshia Tyler , Ricker Colleen , Carter Hannah , Fraley Stephanie I.
Published: July 2017

An initial step in solid tumor metastasis involves the migration of tumor cells through extracellular matrix. Several cancer cell migration strategies exist in vivo, and the local properties of collagen fibers are implicated in modulating migration behaviors. Yet, individual tumor cells also display heterogeneity in their intrinsic ability to migrate and metastasize. It remains unclear to what extent intrinsic and extrinsic heterogeneity contribute to the emergence of distinct migration phenotypes and whether certain migration phenotypes contribute more to metastasis than others. To study this, we generated 3D collagen matrices of varying densities and monitored single cancer cell migration in these matrices with time-lapse microscopy. We observed a collagen density threshold at 2.5mg/ml, above which 86% of MDA-MB-231 breast cancer cells transition from single mesenchymal migration to collective cell migration, with a 50% increase in persistence after cell division. After seven days, these collectively migrating cells created networks coated with basement membrane molecules resembling a clinical phenotype known as vascular mimicry (VM).The remaining 14% of cells migrated randomly and eventually formed spheroids. HT-1080 fibrosarcoma cells also responded similarly, migrating persistently and forming cellular networks. Next we sought to identify the physical feature of high-density collagen driving VM. Neither hypoxia or matrix stiffness was sufficient to induce VM. However, PEG-induced matrix confinement triggered VM network formation. RNA sequencing revealed collectively migrating cells up-regulated a conserved transcriptional program significantly enriched for annotations of vascular development and motility regulation processes. This gene module predicted survival in human tumor transcriptome datasets. Our results suggest that the VM phenotype arises in a subpopulation of cells from a conserved transcriptional and migratory response to confinement in 3D collagen.

Note: This abstract was not presented at the meeting.

Citation Format: Daniel Ortiz, Brian Tsui, Tyler Goshia, Colleen Ricker, Hannah Carter, Stephanie I. Fraley. 3D matrix confinement triggers vascular mimicry through a conserved migratory and transcriptional response [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 1888. doi:10.1158/1538-7445.AM2017-1888
Abstract 1890: PLEK2 contributes to lung cancer progression through upregulation of NDRG1 expression
Authors: Hsieh Yi-Pin , Liu Hui-Chia , Huang Hao-Yu , Tang Wan-Jiun , Lee Tai-Lin , Tsai Meng-Feng
Published: July 2017

PLEK2 is one of the pleckstrin homology domain (PH domain) proteins. Recently studies suggested that PLEK2 may play a critical role in T lymphocyte migration through by PI3K/AKT dependent and independent pathways. However, the biological functions of PLEK2 in lung cancer is not clear. We detected the expression of PLEK2 in various lung adenocarcinoma cell lines using quantitative RT-PCR methods. The results indicated that PLEK2 expression significantly positive correction with cancer cell migration and invasion ability. Forced expression of PLEK2 in lung cancer cells exhibited markedly promoting in the proliferation rate, anchorage independent growth, cell motility and invasion, whereas knockdown of PLEK2 was found to suppress lung cancer cell progression. In addition, we also reported that PLEK2 expression induce lung cancer cell epithelial-mesenchymal transition (EMT) phenomenon, and involve in chemotherapeutic drug resistance through upregulation NDRG1 gene expression. Overexpression of NDRG1 in PLEK2-knockdown cell line restored cancer cell proliferation, migration, and invasion. These results will provide information and help us to understand the roles of NDRG1 in lung cancer cells.

Citation Format: Yi-Pin Hsieh, Hui-Chia Liu, Hao-Yu Huang, Wan-Jiun Tang, Tai-Lin Lee, Meng-Feng Tsai. PLEK2 contributes to lung cancer progression through upregulation of NDRG1 expression [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 1890. doi:10.1158/1538-7445.AM2017-1890
Abstract 1893: Alpha-tubulin acetyltransferase, MEC-17, regulates cancer cell morphology and migration through epithelial-mesenchymal transition suppression and cell polarity disruption
Authors: Lee Cheng-Che , Chang Chi-Yen , Lin Chi-Min , Chang Jang-Yang
Published: July 2017

Acetylation of α-tubulin has characterized as a key process for microtubule stabilization, and it can regulate cell spreading and modulate the dynamics of focal adhesion. MEC-17, a newly identified alpha-tubulin-N-acetyltransferase 1, serves as the major α-tubulin acetyltransferase to promote α-tubulin acetylation in vitro and in vivo. However, the physiological function of MEC-17 in cancer cells and its effect on MT acetylation during cell morphogenesis and migration has remained elusive. In the present study, our results showed that overexpression of MEC-17 induced increment of cell focal adhesion area, suppressed pseudopods formation in three-dimension collagen-embedded cultured environment and inhibited cancer cell migratory and invasive abilities. These changes were further proved to be caused by epithelial-mensenchymal transition (EMT) repression, cell polarity disruption caused by alteration of Golgi orientation and cdc42 activity and the decrease in the phosphorylation of extracellular signal regulatedkinase1/2 (Erk1/2). On the contrary, silencing of endogenous MEC-17 by specific shRNA accelerated the pseudopods formation and EMT process, which lead to facilitating the cell migration. Taken together, these results demonstrated that the important role of MEC-17 in the modulation of intrinsic cellular morphogenesis and migratory and invasive functions through regulation of EMT and polarization. (The study was supported by the following grants: MOST 103-2320-B-006-036-MY3 and MOST 105-2325-B-400-001 from the Ministry of Science and Technology of Taiwan, ROC)

Citation Format: Cheng-Che Lee, Chi-Yen Chang, Chi-Min Lin, Jang-Yang Chang. Alpha-tubulin acetyltransferase, MEC-17, regulates cancer cell morphology and migration through epithelial-mesenchymal transition suppression and cell polarity disruption [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 1893. doi:10.1158/1538-7445.AM2017-1893
Abstract 190: Identification of compound isolated from Beilschmiedia tsangii as a liver cancer specific NRF2 inhibitor
Authors: Chen Yi Siao , Lai Chih Chung , Kuo Yi Ping , Chang Hsun Shuo , Chen Ih Sheng , Yen Chia-Hung
Published: July 2017

Drug resistance is the main cause of cancer recurrence and a major obstacle to the success of anticancer therapy. NRF2, a pivotal transcription factor regulates antioxidant response and detoxification, has been shown to participate in the development of cancer drug resistance. Functional suppression of NRF2 rendered cancer cell more susceptible to anticancer treatments. Beilschmiedia tsangii Merr. (Lauraceae) is a medium-sized evergreen tree. It has been reported that Beilschmiedia extract showed a strong antioxidant activity. In continuation of our bioactivity studies on this species, we tested the effects of 23 compounds isolated from the B. tsangii on NRF2 activity. We identified rel-(7R,8R,7′R,8′R)-3,4,3′,4′-dimethylene-dioxy-5,5′-dimethoxy-7,7′-epoxylignan (BT04) significantly inhibited NRF2 activity in liver cancer cell (Huh7) with an IC50 value of 17 μM, but not in keratinocyte (HacaT cell). By contrast, luteolin, a known NRF2 inhibitor, suppressed NRF2 activity in both Huh7 cell and HacaT cell. Moreover, the mRNA level of NRF2 target genes, NQO1 and HO1, were significantly decreased in Huh7 upon BT04 treatment, while those NRF2 target genes remained unchanged in BT04-treated HacaT cell. A moderate cytotoxic effect of BT04 on Huh7 cell was also observed. Accordingly, our result suggested that BT04 can specifically inhibit NRF2 activity in liver cancer, which in turn indicated that BT04 could be a potential adjuvant to improve chemoresistance.

Citation Format: Yi Siao Chen, Chih Chung Lai, Yi Ping Kuo, Hsun Shuo Chang, Ih Sheng Chen, Chia-Hung Yen. Identification of compound isolated from Beilschmiedia tsangii as a liver cancer specific NRF2 inhibitor [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 190. doi:10.1158/1538-7445.AM2017-190
Abstract 1901: DNMT1 is involved in esophageal squamous cell carcinoma (ESCC) and self-renewal ability of ESCC-cancer stem cells
Authors: Teng Ying , Yu Xiying , Yuan Hui , Guo Liping , Jiang Wei , Lu Shih-Hsin
Published: July 2017

DNA methylation mediated by DNA methyltransferase 1 (DNMT1) plays an important role in carcinogenesis and self-renewal ability of cancer stem cells (CSCs). However, the function of DNMT1 in esophageal squamous cell carcinoma (ESCC) carcinogenesis, especially self-renewal ability of ESCC-CSCs remains unclear. In this study, we found a high expression of DNMT1 in both side population (SP) cells and sphere formation cells that represented as substitutes for CSCs in KYSE150 and EC109 ESCC cell lines. In addition, the expression of DNMT1 was decreased during the differentiation from SP to None-SP (NSP) in these ESCC cells. These results suggested that DNMT1 might have a role in regulating self-renewal and/or differentiation of ESCC-CSCs. To further investigate DNMT1 in ESCC carcinogenesis and self-renewal ability of ESCC-CSCs, we silenced the expression of DNMT1 in KYSE150 and EC109 ESCC cells using lentivirus-mediated RNA interference (RNAi). Our results showed that ablation of DNMT1 expression in KYSE150 and EC109 ESCC cells resulted in decreased their CSCs by SP analysis and sphere formation assay. Meanwhile, ablation of DNMT1 expression inhibited malignant phenotypes in KYSE150 and EC109 cells, including cell proliferation, colony formation, migration and drug resistance abilities. Treatment of 5-aza-2'-deoxycytidine (5-aza-dC), a DNMT inhibitor that led to the degradation of DNMT1 protein by proteasome, revealed that numbers of CSCs and the malignant phenotypes of KYSE150 and EC109 ESCC cells were refrained significantly, including a dramatic inhibition of self-renewal ability of these ESCC-CSCs. Thus, our results indicated that DNMT1 was involved in ESCC carcinogenesis, especially in the maintenance of ESCC-CSCs, suggesting that DNMT1 could be a potential target for ESCC, especially ESCC-CSCs, therapy.

Citation Format: Ying Teng, Xiying Yu, Hui Yuan, Liping Guo, Wei Jiang, Shih-Hsin Lu. DNMT1 is involved in esophageal squamous cell carcinoma (ESCC) and self-renewal ability of ESCC-cancer stem 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 1901. doi:10.1158/1538-7445.AM2017-1901
Abstract 191: Double blockade of interacting CK2 and EGFR pathways by tumor-targeting nanobioconjugates increases therapeutic efficacy against glioblastoma multiforme
Authors: Ljubimova Julia Y.
Published: July 2017

Introduction: Glioblastoma multiforme (GBM) remains the deadliest brain tumor in adults, and is notorious for drug and radiation resistance. To inhibit GBMs more effectively, polymalic acid-based blood-brain barrier crossing nanobioconjugates were synthesized that are delivered to the cytoplasm of cancer cells and specifically inhibit the master regulator serine/threonine protein kinase CK2 and the wild-type/mutated epidermal growth factor receptor (EGFR/EGFRvIII), which are overexpressed in gliomas according to The Cancer Genome Atlas (TCGA) GBM database.

Methods and Results: The used nanobioconjugates are novel nanotherapeutics where all moieties are covalently connected to poly(β-L-malic acid) (PMLA). Our biodegradable and non-toxic nanodrugs bind to the receptors enriched on tumor vasculature and cross the BBB by transcytosis. They specifically bind to cancer cells and after internalization exit to the tumor cell cytoplasm using pH-sensitive endosomal disruption unit. Two xenogeneic mouse models bearing intracranial human GBMs from cell lines LN229 and U87MG that expressed both CK2 and EGFR were used. The knockdown of CK2α and EGFR/EGFRvIII suppressed their downstream prosurvival signaling. Treatment also markedly reduced the expression of programmed death-ligand 1 (PD-L1), a negative regulator of cytotoxic lymphocytes. Downregulation of CK2 and EGFR also caused suppression of heat shock protein 90 (Hsp90) co-chaperone Cdc37, which may inhibit the activity of key cellular kinases. Inhibition of either target was associated with downregulation of the other target as well, which may underlie efficacy of the dual nanobioconjugate that is directed against both CK2 and EGFR. Importantly, the single nanodrugs, and especially the dual nanodrug, markedly suppressed the expression of cancer stem cell markers c-Myc, CD133, and nestin, which could contribute to the efficacy of these nanodrugs. In both tumor models, the dually targeting nanobioconjugate significantly increased (up to 2-fold) animal survival compared with the control group.

Conclusion: The versatile nanobioconjugates developed in this study, with the ability of anti-cancer drug delivery across biobarriers and inhibition of key tumor regulators, offer a promising nanotherapeutic approach to treat GBMs and to potentially prevent drug resistance and retard the brain tumor recurrence.

Support: NIH grants U01 CA151815, R01 CA136841, R01 CA188743, R01 CA209921, R01 EY013431

Citation Format: Julia Y. Ljubimova. Double blockade of interacting CK2 and EGFR pathways by tumor-targeting nanobioconjugates increases therapeutic efficacy against glioblastoma multiforme [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 191. doi:10.1158/1538-7445.AM2017-191
Abstract 1910: NF-kappaB classical versus alternative pathways support distinct populations of ovarian cancer tumor-initiating cells
Authors: House Carrie D. , Annunziata Christina M.
Published: July 2017

Ovarian cancer is the most lethal gynecological malignancy in the United States with high morbidity and mortality due to recurrence and chemoresistance. Our data suggest tumor-initiating cells (TICs) play an important role in disease biology. We previously showed that a subset of ovarian cancer cells depends on NF-kappaB signaling, and that expression of NF-kappaB proteins is associated with poor survival. Given that NF-kappaB expression correlates with a poor outcome in ovarian cancer, and NF-kappaB activity supports drug resistance and tumorigenicity, we hypothesize that NF-kappaB supports a TIC program responsible for ovarian cancer relapse. To investigate this pathway in TICs, we designed a novel method to enrich for TICs from cell lines and patient samples by culturing non-adherent, floating cells in stem cell conditions defined by low attachment flasks and serum free media. Preliminary data confirm that these cells have higher stem cell marker expression, are chemoresistant, and are more tumorigenic in nude mice compared to their adherent counterparts. These TIC-enriched culture conditions enhance NF-kappaB expression and activity. More specifically, alternative NF-kappaB signaling through the RelB transcription factor supports TIC populations by regulating aldehyde dehydrogenase (ALDH), an enzyme with high activity in TICs. Using an inducible shRNA targeting RelB we show that spheroid formation, ALDH expression and activity, chemoresistance, and tumorigenesis in both subcutaneous and intrabursal xenograft models, significantly decreased in the absence of RelB. Interestingly, loss of classical NF-kappaB signaling, through an shRNA targeting the RelA transcription factor, was less effective in targeting TICs, but more effective at targeting a proliferative subpopulation with high Ki67 staining. We conclude that classical and alternative NF-kappaB signaling support ovarian tumor cells with distinct phenotypes and the collaboration of these pathways may be critical for supporting tumor repopulation following chemotherapy. Current studies will measure system level changes induced by these shRNAs, and identify a gene signature specific to each NF-kappaB pathway in ovarian TICs. Clarifying the nuances of NF-kappaB signaling in TICs will increase our understanding of ovarian cancer recurrence and further focus therapeutic strategies to prevent relapse.

Citation Format: Carrie D. House, Christina M. Annunziata. NF-kappaB classical versus alternative pathways support distinct populations of ovarian cancer tumor-initiating 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 1910. doi:10.1158/1538-7445.AM2017-1910
Abstract 1912: Actn4, a novel therapeutic target of dietary ellagic acid, promotes breast cancer metastasis via mediating cancer stem cells
Authors: Wang Neng , Wang Zhiyu , Xie Xiaoming
Published: July 2017

Purpose: Pharmacology-based target identification has become a novel stratey leading to the discovery of novel pathological biomarkers. Ellagic acid (EA), a dietary polyphenol compound, exhibits potent anticancer activities, whereas the underlying mechanisms remain unclear. This study sought to determine the role and regulation of ACTN4 expression in human breast cancer metastasis and EA-based therapy.

Experimental Design: The anti-metastasis ability of EA was validated by MMTV-PyMT mice and in vitro cell models. Drug affiity responsive target stability (DARTS) was utilized to identify ACTN4 as the direct target of EA in breast breast cancer stem cells (CSCs). The metastatic regulated mechanisms of ACTN4 were assessed by CSC-related assays including mammosphere formation, tumorigenic ability, reattachment differentiation and signaling pathway analysis. The clinical significance of ACTN4 was based on human tissue microarray analysis and TCGA database exploration.

Results: EA inhibited breast cancer growth and metastasis via directly targeting ACTN4 in vitro and in vivo, accompanied with limited CSCs population. ACTN4 knockdown resulted in blockage of malignant cell proliferation, colony formation and ameliorated metastasis potency. ACTN4 positive CSCs exhibited higher ESA+ proportion, increased mammosphere-formation ability, as well as enhanced in vivo tumorigenesis ability. Increased ACTN4 expression was directly associated with later cancer stage, increased incidence of metastasis, and poor overall survival period.

Conclusions: ACTN4 plays an important role in breast CSCs-related metastasis and is a novel therapeutic target of EA treatment.

Note: This abstract was not presented at the meeting.

Citation Format: Neng Wang, Zhiyu Wang, Xiaoming Xie. Actn4, a novel therapeutic target of dietary ellagic acid, promotes breast cancer metastasis via mediating cancer stem 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 1912. doi:10.1158/1538-7445.AM2017-1912
Abstract 1919: Twist1 modulates paclitaxel-induced cancer stem cell enrichment in triple-negative breast cancer
Authors: Yang Aimin , He Xiaoyuan , Schulte Bradley A. , Carroll Steven L. , Ethier Stephen P. , Wang Gavin Y.
Published: July 2017

Triple-negative breast cancer (TNBC), the most aggressive subtype of breast cancers, is highly refractory to chemotherapy and has a high incidence of metastasis and tumor relapse. Targeted therapies for TNBC do not exist because this subtype lacks druggable hormone receptors and HER2 amplification or overexpression. Although Taxane-based chemotherapy is a standard of care for TNBC treatment, paclitaxel (Taxol)-induced cancer stem cell (CSC) enrichment presents a significant challenge to the success of breast cancer treatment. Thus, there is a critical need to understand the mechanisms by which chemotherapy induces CSC enrichment in residual tumors following anticancer therapies. Here we report that Taxol-induced enrichment for CSCs correlates well with a marked upregulation of Twist1 expression in human TNBC cells. Knockdown of Twist1 inhibits the clonogenic capacity of TNBC cells in vitro and TNBC tumorigenesis in vivo. Mammosphere formation assays indicate that silencing of Twist1 greatly diminishes the tumor sphere-forming potential of breast CSCs. Furthermore, limited dilution assays and stem cell xenotransplantation reveal that knockdown of Twist1 expression decreases the frequency of CSCs by 72-fold in human TNBC cells. More importantly, we show that silencing of Twist1 blocks Taxol-induced CSC enrichment in residual tumor cells that have survived drug treatment. Together, these results demonstrate a previously unrecognized role for Twist1 in mediating Taxol-induced CSC enrichment in residual tumors of human TNBC and suggest that targeted inhibition of the Twist1 signaling pathway may represent a novel therapeutic strategy to tackle therapy-induced CSC enrichment in breast cancer treatment.

Citation Format: Aimin Yang, Xiaoyuan He, Bradley A. Schulte, Steven L. Carroll, Stephen P. Ethier, Gavin Y. Wang. Twist1 modulates paclitaxel-induced cancer stem cell enrichment in triple-negative 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 1919. doi:10.1158/1538-7445.AM2017-1919
Abstract 1923: Paired isolation and expansion of CSC and CTC from primary small cell lung cancer patient tissue and blood using the 3DKUBE bioreactor platform
Authors: Millard Melissa , Lotstein Alina , Holmes Lillia , Schammel David , Chung Ki , Edenfield Jeff , Crosswell Hal E. , DesRochers Tessa
Published: July 2017

Surgical resection is rarely an option for small cell lung cancer (SCLC) patients as the majority present with extensive disease at diagnosis. This scarcity of patient samples suitable for research presents a significant road block for the development of SCLC targeted-therapeutics. To address the problem of tissue scarcity, we have developed a method for the isolation and expansion of cancer stem cells (CSC) and circulating tumor cells (CTC) from primary tissues and blood of SCLC patients using the 3DKUBE™ perfusion microbioreactor. We have established a label-free, combined chemical and functional selection method for the isolation of CSCs from SCLC samples, solid tumor as well as blood, that does not rely upon the bias imposed by marker-based selection. Cells enriched in this manner were further purified and expanded under optimized conditions (growth factors, ECM, scaffolding and oxygen tension) within the 3DKUBE™ perfusion microbioreactor. These isolated and expanded CSCs have maintained resistance to cisplatin and etoposide, stabilized the expression of traditional CSC markers, and been validated in vitro through serial spheroid formation assays. These CSCs are currently being characterized and compared to parental tissue through correlative genomic and phenomic analysis and validated through in vivo tumorigenesis models. These cells will be utilized to generate 3D microtumors to accurately predict SCLC drug response in vitro, a determination that is not accurately performed in conventional 2D cell culture and is inhibited by both cost and time in patient-derived xenografts (PDX)

Citation Format: Melissa Millard, Alina Lotstein, Lillia Holmes, David Schammel, Ki Chung, Jeff Edenfield, Hal E. Crosswell, Tessa DesRochers. Paired isolation and expansion of CSC and CTC from primary small cell lung cancer patient tissue and blood using the 3DKUBE bioreactor platform [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 1923. doi:10.1158/1538-7445.AM2017-1923
Abstract 1941: Cell surface vimentin is a novel marker for CTC detection in neuroblastoma
Authors: Batth Izhar S. , Li Heming , Sholler Giselle Saulnier , Li Shulin
Published: July 2017

Among children in the United States, brain cancers now account for most number of cancer-related deaths. Neuroblastomas (NB) and sarcomas account for 13% of all childhood cancers in the United States. Despite significant progress yielding increased 5-year survival, 1250 deaths are expected this year from childhood cancers and cancer incidence has been steadily increasing. One of the key contributors to cancer mortality is tumor metastasis. It is generally believed that CTCs are shed into the circulation from primary tumors and contain unique driver mutations enabling their aggressive phenotype. However, detection of CTCs from NB is difficult as there is no direct method. Our lab has developed a monoclonal antibody targeting vimentin on the cells’ surface. Cell surface vimentin (CSV) is only observed in tumor cells; it remains intracellular in normal cells. We have published data demonstrating the superior specificity and sensitivity of our approach in breast, colon, and prostate cancer. Here, we report direct CTC detection in NB using our CSV mAb. As part of our collaborative effort analyzing NB blood samples from a multicenter Phase II trial, we present novel discoveries regarding treatment of NB with difluoromethylornithine (DFMO) and its effects on CTC release into the circulation in patients under remission. Among our observations, approximately ~1/3 patients have low or no CTCs while ~1/4 with high numbers of CTC are responding to DFMO treatment. Remaining patients show oscillating CTC numbers. Further, treatment with DFMO showed a statistically significant decline in CTCs after the beginning of therapy. Ongoing work including whole genome analysis can possibly reveal new insight into CTCs’ entering the circulation. These data demonstrate that our CTC capture using CSV is a novel and unique approach for detection in NB.

Citation Format: Izhar S. Batth, Heming Li, Giselle Saulnier Sholler, Shulin Li. Cell surface vimentin is a novel marker for CTC detection in neuroblastoma [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 1941. doi:10.1158/1538-7445.AM2017-1941
Abstract 1957: Molecular pathogenesis and drug synergism in a zebrafish model of high risk neuroblastoma
Authors: He Shuning , Mansour Marc R. , Zimmerman Mark W. , Layden Hillary M. , Look A. Thomas
Published: July 2017

We have developed a transgenic zebrafish model that overexpresses MYCN and harbors loss-of-function mutations of the nf1 tumor suppressor. In this model, loss of nf1 leads to aberrant activation of RAS-MAPK signaling, promoting both increased tumor cell survival and rapid tumor cell proliferation. These neuroblastomas are very aggressive in that almost all of the fish develop neuroblastoma by 3 weeks of age. Three-week old juvenile fish are very small, making it feasible to test the effectiveness of many drugs and drug combinations in vivo for activity against the primary tumors. We demonstrate these advantages of the model by showing marked synergistic anti-tumor effects of a MEK inhibitor (trametinib) and a retinoid (isotretinoin) in vivo at several different dosage combinations by in vivo isobologram analysis. Thus, inhibition of RAS-MAPK signaling can significantly improve the treatment of this very aggressive form of neuroblastoma when it is combined with the inhibition of other key pathways. Because of the very high penetrance and rapid onset of neuroblastoma in our nf1-deficient, MYCN-transgenic zebrafish model, it is one of the only model systems in which extensive analysis of the synergistic activity of two or more drugs can be evaluated in primary tumors in vivo. This capability is especially valuable given that mutations causing RAS-MAPK pathway hyperactivation have been shown to arise frequently at the time of relapse of childhood neuroblastomas, indicating the need to eliminate these mutated tumor cells as a component of the primary treatment.

Note: This abstract was not presented at the meeting.

Citation Format: Shuning He, Marc R. Mansour, Mark W. Zimmerman, Hillary M. Layden, A. Thomas Look. Molecular pathogenesis and drug synergism in a zebrafish model of high risk neuroblastoma [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 1957. doi:10.1158/1538-7445.AM2017-1957
Abstract 197: Anti-cancer activity of extract from the Jamaican round-leaf yellow yam (RLY2) (Dioscorea cayenensis)
Authors: Wright Sasha-Gay A. , Gray Wesley G. , Asemota Helen
Published: July 2017

The Jamaican Round-Leaf yellow yams (RLY2), Dioscorea cayenensis, are edible tubers, bulbils or rhizomes that are of considerable economic value and possess several health benefits. These RLY2 are a rich source of anti-oxidants, vitamins and phytochemicals. In addition to its nutritional value, the Jamaican populace regards RLY2 as an herbal medicine useful in treatment of diabetes mellitus, hypertension and certain kind of cancers. Chemical analysis of RLY2 revealed the presence of a myriad of bioactive ingredients that are likely to be lost due to the method of preparation for consumption. Thus, we hypothesized that mild extraction of RLY2 will preserved the bioactive analytes that give RLY2 its anti-cancer property. To test this hypothesis, different ethanolic extracts of RLY2 were prepared, and their bioactivity demonstrated in two models of prostate cancer. The present study demonstrates dosage and time-dependence inhibition in both the androgen sensitive LNCaP and androgen insensitive DU-145 prostate cancer cell lines. We observed that DU-145 was three-times more sensitive to RLY2 ethanol extract than LNCaP. Growth of LNCaP for 3-days with varying concentration of RLY2 ethanol extract resulted in an IC50 of 750 ppm (95% C.I. 726-791ppm), whereas DU-145 resulted in an IC 50 of 250 ppm (95% C.I. 236-281ppm). The maximum growth inhibition by RLY2 extract occurs within twenty-four hours for both LNCaP and DU-145 with no significant changes after 5-days. To determine the mechanism of toxicity by RLY2, we induced both LNCaP and DU-145 with RLY2 for 0-24h and prepared cells for flow cytometer analysis. The effect of RLY2 on cell cycle and degree of apoptosis will be discussed. Our data indicated that the ethanol extract of RLY2 was more sensitive toward androgen-insensitive prostate cancer. Thus, this study suggests that RLY2 contain bioactive chemical that may be used in grade II prostate adenocarcinoma represented by the DU-145 phenotype.

Citation Format: Sasha-Gay A. Wright, Wesley G. Gray, Helen Asemota. Anti-cancer activity of extract from the Jamaican round-leaf yellow yam (RLY2) (Dioscorea cayenensis) [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 197. doi:10.1158/1538-7445.AM2017-197
Abstract 1975: FAM83B: A novel regulator of cell plasticity in breast cancer
Authors: Bartel Courtney A. , Junk Damian J. , Jackson Mark W.
Published: July 2017

Epithelial to mesenchymal transition (EMT) is an important process in both metastasis and cancer stem cell (CSC) enrichment. Recent studies suggest that instead of simply transitioning from one cell state to another, cancer cells exist along a continuum of epithelial and mesenchymal cell states. Identifying novel regulators of tumor cell plasticity will be critical to fully understand this continuum and to target metastasis and CSC phenotypes in the future. FAM83B is a novel oncogene identified by the Jackson Laboratory in a forward genetic screen for drivers of Human Mammary Epithelial Cell (HMEC) transformation. Previous work showed that FAM83B expression is elevated in triple negative breast cancers and that FAM83B also activates key cell signaling pathways (EGFR, MAPK, and PI3K) in breast cancers. Here, we implicate FAM83B as a novel regulator of epithelial-mesenchymal plasticity using a HMEC transformation model. Transformation of primary HMEC by expressing shp16, shp53, c-Myc, and RAS results in the generation of two distinct transformed cell populations. One population retains epithelial characteristics, while an emergent population spontaneously acquires a mesenchymal morphology and a CD24LOCD44HI (CSC) cell surface marker profile. Moreover, isolation of epithelial, CD24HICD44LO cells (non-CSC) and exposure to Oncostatin M (OSM), an EMT-inducing cytokine, can also generate cells with a mesenchymal/CSC phenotype. Interestingly, FAM83B expression was significantly elevated in the epithelial/non-CSC population compared to the mesenchymal/CSC population. Moreover, treatment of purified epithelial/non-CSC cells with OSM resulted in decreased FAM83B expression levels, indicating FAM83B expression is suppressed as the cells move through EMT. FAM83B expression also correlated with an epithelial phenotype in a panel of breast cancer cell lines. shRNA-mediated knock-down of FAM83B from epithelial/non-CSC resulted in increased spontaneous EMT, concomitant with elevated expression of the mesenchymal marker Vimentin and master EMT transcription factor Zeb1. Following treatment with OSM, sh83B cells maintain prolonged, elevated p-Stat3 and p-ERK signaling, known contributors to the mesenchymal/CSC phenotype. Conversely, OSM-induced EMT was blunted in epithelial/non-CSC expressing exogenous FAM83B. Thus, FAM83B expression is a determinant in maintaining an epithelial phenotype, while suppression of FAM83B is important during EMT. Future work will seek to define novel FAM83B-mediated signaling pathways important for regulating cellular plasticity.

Citation Format: Courtney A. Bartel, Damian J. Junk, Mark W. Jackson. FAM83B: A novel regulator of cell plasticity in 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 1975. doi:10.1158/1538-7445.AM2017-1975
Abstract 1978: Identification of the metastatic cell populations in a spontaneous mouse model of melanoma
Authors: Li Xiaoshuang , Torres Raul , Kos Lidia
Published: July 2017

Melanoma is the deadliest form of skin cancer due to its high propensity to metastasize and resistance to current therapies. We have created a spontaneous mouse model of metastatic melanoma (Dct-Grm1/K5-Edn3) where metastasis to the lungs is 80% penetrant. The primary tumors of these mice present cellular heterogeneity with cells at varying levels of differentiation. The main goal of this study is to determine the metastatic potential of the primary tumor resident Tyrosinase positive cells and evaluate the dynamic pattern of gene expression as those cells move from the primary tumors to the sites of metastasis. To accomplish this aim we crossed the Dct-Grm1/K5-Edn3 mice to CreERT2/ ROSAmT/mG mice to indelibly label Tyrosinase cell populations within the primary tumor by topical application of 4-hydroxytamoxifen at the tumor site. In vivo lineage tracing and characterization of those labeled cells was performed in the metastatic lesions. We found that Tyrosinase positive cells enter the circulation before the appearance of any noticeable tumor or nevus and establish close interactions with the vasculature as single cells. Metastatic cells in close association with the inner wall of the vasculature lose pigmentation and do not express melanocytic markers. Interestingly, those intravascular cells mimic endothelial cell properties with the expression of platelet endothelial cell adhesion molecule (PECAM-1, also known as CD31). In the lung tissue, the primary tumor derived Tyrosinase positive cells or their progeny can survive and establish successful metastases with pigmentation. This in vivo lineage tracing system in mouse will be a powerful model to evaluate and help us understand the etiology and pathogenesis of melanoma metastasis. Further characterization of those more aggressive cells in melanoma will allow for the development of new prognostic tests and novel therapeutic strategies to eliminate metastasis.

Citation Format: Xiaoshuang Li, Raul Torres, Lidia Kos. Identification of the metastatic cell populations in a spontaneous mouse model of melanoma [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 1978. doi:10.1158/1538-7445.AM2017-1978