bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 1965: A novel biocompatible fluorescent nanoparticle enables enhanced live cell tagging and tracking of cancer cells
Authors: Asbrock Nick , Chu Vi , Su Kevin , Tang Ben Zhong , Liu Bin
Published: July 2017

Metastasis is the leading cause of cancer mortality. Metastasis is a multi-step process which includes local tumor cell invasion, cell migration into the vasculature, exit of cells from the circulation and colonization at the distal tissue sites. Long-term noninvasive cell tracking by fluorescent probes is of great importance to life science and biomedical engineering. Current methods used to fluorescently tag cancer cells have been limited by short signal duration, high background auto-fluorescence or lengthy cell line generation using GFP. We have developed a biocompatible fluorescent nanoparticle which relies on Aggregation Induced Emission (AIE) technology that are highly resistant to fluorescent signal quenching. These particles enable highly efficient live cell fluorescent tagging while retaining fluorescent signal for up to 10 days in vitro and 21 days in vivo. These nanoparticles will open new avenues in the development of fluorescent probes for following biological processes such as carcinogenesis.

Citation Format: Nick Asbrock, Vi Chu, Kevin Su, Ben Zhong Tang, Bin Liu. A novel biocompatible fluorescent nanoparticle enables enhanced live cell tagging and tracking of 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 1965. doi:10.1158/1538-7445.AM2017-1965
Abstract 1968: A novel mechanism of metastasis: Extracellular ATP promotes invasion and metastasis independent of purinergic receptor signaling
Authors: Cao Yanyang , Wang Xuan , Chen Xiaozhuo
Published: July 2017

Cancer is one of the top deadliest diseases in the US and worldwide. Metastasis, the dissemination of cancer cells from the primary tumors to distant organs, is responsible for 90% of solid tumor-related deaths. Tumor invasion and metastasis is a multistep process in which loss of cell-cell adhesion, increased proteolysis, and cell motility has been shown to be critical steps. Extracellular ATP is potentially a very important factor involved in tumor invasion and metastasis because both cell detachment and migration require energy, which is known to be mainly provided by ATP. Recent studies have indicated that the extracellular microenvironment of tumors contains much higher concentrations of ATP than normal tissues of the same cell origins. Our recent studies demonstrated that extracellular ATP is taken up by cancer cells through macropinocytosis and other endocytosis and promotes cancer cell growth, survival, and drug resistance (1-3). Based on all these, we hypothesized that extracellular ATP (eATP) plays critical roles in the regulation of tumor cell detachment, motility, invasion and tumor metastasis initiation. It was previously shown that ATP-induced purinergic receptor (PR) signaling is involved in metastasis. Our hypothesis is different in that eATP also mediates invasion and metastasis independent of PR signaling. Various bioassays were used in human non-small cell lung cancer (NSCLC) A549 cells to test our hypothesis. Our results show that eATP treatment led to a substantially increased number of floating cancer cells, and these cells were viable and formed clones in a clonogenic assay. This indicates that eATP induces cancer cell detachment. Moreover, treatment of eATP also induces cell migration in cell wounding and Transwell migration assays. In vitro invasion assay showed that eATP induced a dose-and time-dependent increase in the invasive capacities of the A549 cells. Western blot analysis indicates that eATP treatment reduced the expression of cell-cell adhesion molecule E-cadherin. PR inhibitors only slightly attenuated these effects. All these suggest novel ATP mechanisms independent of the PR signaling that are unreported before and imply novel targets for inhibiting/preventing metastasis.

References

1. Qian et al. Cancer Letters 351; 242-251 (2014).

2. Chen, Qian, and Wu. Free Radical Biol Med 79; 253-263 (2015)

3. Qian et al. Mol Cancer Res 14(11); 1087-1096 (2016)

Citation Format: Yanyang Cao, Xuan Wang, Xiaozhuo Chen. A novel mechanism of metastasis: Extracellular ATP promotes invasion and metastasis independent of purinergic receptor signaling [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 1968. doi:10.1158/1538-7445.AM2017-1968
Abstract 1976: Dried blood imaging and immunoassay: Spot formation, particle migration, and tumor cell detection
Authors: Shen Quanxu , Hong Bin
Published: July 2017

Blood droplet, when dried, forms a structured sedimentation pattern with central flat, corona ring and peripheral rim. This pattern can be fine-tuned with the blood formula. Surfactant is critical to promote the gelation process, eliminate the film cracking and delamination, and hence, suppress the coffee-ring effect. Additionally, surfactant restrains the shrinkage of the dried film. Without surfactant, the contraction was 100~150µm for 20µL of blood; decreased with surfactant added; fully stopped at 10% of concentration. Drying at room temperature with surfactant formed a flat disc-shaped deposit, while at 37°C, volcanic protuberance was developed. The size of the protuberance depended on the concentration of the surfactant primarily, and the anticoagulant type, evaporation velocity, and blood volume. To monitor the dynamic desiccation process, video recording of the evaporating drop was employed. It revealed a quick dislocation of the leukocyte-resembling beads to the outer region of the blood spot, reportedly at velocity of 10µm/sec. The use of 1 and 10µm sized beads further demonstrated layered convective flow below the surface. Beads migrated outward primarily before gelation, inward slightly during solidification, and ultimately settled down across the spot. The movement of beads was found in the range of a few hundred microns to millimeters before and after desiccation for a 50µL drop. Notably, plasma proteins and saline have influenced the bead distribution more than the surfactant. After plasma removal and mixing with surfactant, the majority of beads were dragged to the periphery, compared with many beads for no plasma and surfactant, some for whole blood with surfactant, and none for whole blood without surfactant. For a thick blood film, detection of embedded cells and beads can be difficult. Experiments showed that beam of longer wavelength, 532nm, was capable of visualizing all fluorescent cells and beads. Dried blood spot (DBS) assay has been widely used for newborn metabolic testing and DNA analysis. To detect rare tumor cells in DBS, the dried pattern was optimized to eliminate the artifacts, stabilize the cells, and enrich the targeted cell. DBS assay holds greater potential for cancer detection when the medical resource is limited.

Note: This abstract was not presented at the meeting.

Citation Format: Quanxu Shen, Bin Hong. Dried blood imaging and immunoassay: Spot formation, particle migration, and tumor cell detection [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 1976. doi:10.1158/1538-7445.AM2017-1976
Abstract 1982: β-arrestin 2 mediates tumor growth and metastasis in renal cell carcinoma cells
Authors: Masannat Jude , Zhang Yushan , Purayil Hamsa , Mahmud Iqbal , Daaka Yehia
Published: July 2017

Renal Cell Carcinoma (RCC) is one of the most lethal urological cancers worldwide, with incidence and mortality rates increasing in the past two decades. The disease does not present early clinical symptoms and is commonly diagnosed at the metastatic stage, leaving the 5-year survival rate at ≈ 10-20%. For a wide array of neoplasms, many key molecular determinants involved in mediating the process of tumor cell growth, invasion, and colonization at a secondary site (i.e. metastasis) have been reported. However, few molecular predictors have been identified for RCC, rendering the mechanism(s) underlying RCC metastases poorly understood. This results in the lack of effective treatment for patients with advanced RCC.

G protein-coupled receptors (GPCRs) and their effectors, such as the arrestin proteins, have been implicated in tumor growth, metastasis, and angiogenesis. Arrestin proteins are well known for their function in the desensitization and trafficking of GPCRs, but have also been implicated in unique signaling pathways to regulate fundamental cellular functions, including cell cycle progression, cell migration, and survival. Furthermore, arrestin involvement has been identified in a number of breast, colorectal, lung, and hematological malignancies. However, the role of arrestin proteins in RCC is yet to be determined. Our preliminary data show that β-arrestin 2 (βarr2) protein levels correlate with growth and metastatic potential in several RCC cell lines, including ACHN and SN12C. We hypothesize that βarr2 regulates RCC tumor progression, specifically through involvement in proliferation, invasion, and metastatic processes. To test our hypothesis, we used genetic-based loss of function approaches such as interfering RNA and CRISPR/Cas9. βarr2 knockdown results indicated a role in RCC malignancy as it significantly reduces the migration and invasion of RCC cell lines in vitro. βarr2 knockout (KO) impaired 3D spheroid formation of these cells and induced morphological changes compared to control cells as observed under confocal microscopy imaging. Moreover, epithelial marker E-cadherin expression levels were elevated while mesenchymal markers twist1, twist2 and vimentin levels were decreased in the βarr2 KO cells compared to control, indicating a mesenchymal to epithelial transition. In vivo data support our hypothesis that βarr2 plays a critical role in tumor growth and metastasis. Our data suggests a role for βarr2 in RCC malignancy and present a possible target in development of therapies for patients with advanced RCC.

Citation Format: Jude Masannat, Yushan Zhang, Hamsa Purayil, Iqbal Mahmud, Yehia Daaka. β-arrestin 2 mediates tumor growth and metastasis in renal cell carcinoma 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 1982. doi:10.1158/1538-7445.AM2017-1982
Abstract 1987: Inhibition of collagen receptor discoidin domain receptor-1 (DDR1) reduces gastric cancer cell motility and metastasis
Authors: Yuge Ryo , Kitadai Yasuhiko , Takigawa Hidehiko , Tanaka Shinji , Chayama Kazuaki , Yasui Wataru
Published: July 2017

Accumulating evidences suggest that a unique set of receptor tyrosine kinases, known as discoidin domain receptors (DDRs), play a role in cancer progression by interaction with their surrounding collagen matrix. Although abnormal expression of DDRs is reported in some human cancers, little is known about the expression and function of DDRs in gastric cancer progression. In this study, we investigated expression and the role of DDR1 in the tumor progression of human gastric cancer. The expression and distribution of DDR1 was analyzed by immunohistochemistry in 127 human gastric cancer cases, and the expression level of DDR1 in 7 human gastric cancer cell lines was analyzed by RT-PCR and western blotting. Proliferation, migration, invasion, and tube formation assays were conducted in DDR1 silenced gastric cancer cells. The effect of DDR1 on the tumor growth and metastasis were examined in orthotopically implanted nude mice model and a model of liver metastasis. DDR1 was expressed in human gastric cancer cell lines, and expression of DDR1 in human gastric tumor was associated with poor prognosis. Among 7 gastric cancer cell lines, MKN74 expressed DDR1 at highest level. DDR1-silenced MKN74 cells showed unaltered proliferation activity. In contrast, migration, invasion, and tube formation were significantly reduced. When examined in an orthotopic nude mouse model, DDR1-silenced implanted tumor significantly decreased angiogenesis and lymphangiogensesis, thereby leading to reduction of lymph node metastasis and liver metastasis. We showed that treatment of DDR1 inhibitor also inhibited lymph node metastasis in an orthotopic nude mouse model These results suggest that DDR1 is involved in GC tumor progression and metastasis. DDR1 could be not only an independent prognostic classifier, but also a promising therapeutic target in patients with GC.

Citation Format: Ryo Yuge, Yasuhiko Kitadai, Hidehiko Takigawa, Shinji Tanaka, Kazuaki Chayama, Wataru Yasui. Inhibition of collagen receptor discoidin domain receptor-1 (DDR1) reduces gastric cancer cell motility and metastasis [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 1987. doi:10.1158/1538-7445.AM2017-1987
Abstract 1999: Cofactor Paragon: a novel tool to analyze the tumor microenvironment using RNAseq
Authors: Bloom Ryan , Talwar Raman , Hiken Jeff , Armstrong Jon
Published: July 2017

The impact of cancer immunotherapy on clinical cancer care is growing rapidly. However, there are several mechanisms by which a tumor can avoid recognition and/or elimination by the immune system. Immune recognition, activation, and infiltration are each required for effective clearance of a tumor by the immune system. Impairment of any one of these mechanisms requires a different therapeutic strategy or combination of strategies to significantly address. The development of new multi-modal biomarker technologies that have the ability to provide insight into each of these factors in a cost-effective manner is essential to effectively guide treatment choice for patients and to discover new therapeutic targets.

We have developed Paragon, which is an RNA sequencing based panel that utilizes novel informatics technologies to provide a comprehensive picture of a tumor’s transcriptomic and immune micro-environment. There are three distinct outputs of Paragon: measurement of the expression levels of ten immune checkpoint genes, quantification of the total mutational burden of the tumor, and the levels of infiltration of 24 different immune cell subtypes within the tumor microenvironment. These outputs collectively inform the various mechanisms that tumors use to evade recognition and clearance by the immune system.

We show that Cofactor Paragon accurately reports on gene expression, mutational burden and infiltrating leukocytes compared to gold standard methods from just 20 ng of FFPE tumor RNA. We further analyze the data to show the correlation between mutational burden and infiltrating CD4+ and CD8+ T-cell levels. Finally, we show how Paragon can identify expression of genes involved in inhibitory tumor metabolism that correlate with resistance to PD-1 blockade therapy. These results position Cofactor Paragon as a novel tool that can help identify ideal therapeutic strategies in immuno-oncology.

Citation Format: Ryan Bloom, Raman Talwar, Jeff Hiken, Jon Armstrong. Cofactor Paragon: a novel tool to analyze the tumor microenvironment using RNAseq [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 1999. doi:10.1158/1538-7445.AM2017-1999
Abstract 2008: Intestinal microbiota may dynamically facilitate the anti-PD-L1 immunotherapy
Authors: Xue Jia , Wang Zhun , Guo Sheng , Cai Jie , Ouyang Davy , Cai Bin , Chen Gang , Liu Jie , Dong Xin , Li Henry
Published: July 2017

Cancer immunotherapies, e.g. the antibody against programmed death ligand 1 (PD-L1), a checkpoint inhibitor, have witnessed great successes in treating certain cancers in recent years. Recent data have also demonstrated that gut microbiota are important modulators on anticancer immunotherapy1,2. Heterogeneity in patient outcome seems to suggest complex communications between microbiota and host antitumor immunity. To this end, we tested an engineered chimeric MC38 mouse cell line, hPDL1-MC38-HuCELL™ via human PD-L1 knock-in procedure, where MC38 CRC syngeneic cell is derived from C57BL/6. After treatment of PD-L1 antibodies (cD7A8 and BMS PD-L1 of different dose regimens), we observed significantly different drug responses among the mice from three different Chinese rodent suppliers: the mice from Vendor 1 showed no tumor progression after treatment with a variety of doses while no favorable response was observed in mice from Vendor 2 and Vendor 3. To deeply study the gut microbiota of these mice, we performed 16S ribosomal RNA sequencing on untreated mice from three groups (5 replicates for each). Global diversity analysis by Quantitative Insights Into Microbial Ecology (QIIME) tool revealed a clear separation in the three sources of mice: the microbiota composition of Vendor 2 and Vendor 1 are relatively closer to each other whereas the Vendor 3 mice are different, suggesting that the main difference seen between Vendor 1/2 and 3 in the original composition of gut microbiota is not the key impact for the observed anti-PD-L1 efficacy, and there should be other complex dynamics impacted anti-PD-L1 treatment, which remains unknown. Moreover, a group of 27 taxa were identified with significant difference in abundance (Kruskal-Wallis test, p-value < 0.05) across the groups, such as Bacteroidaceae, Lachnospiraceae, and Ruminococcaceae, which confirmed the previous data1. In conclusion, intestinal microbiota dynamically facilitate anti-PD-L1 efficacy and reversely anti-PD-L1 treatment could influence reconstruction of gut microbiota.

References 1. Sivan A, et al. Commensal Bifidobacterium promotes antitumor immunity and facilitates anti-PD-L1 efficacy. Science 2015;350(6264):1084-9. 2. Vétizou M, et al., Anticancer immunotherapy by CTLA-4 blockade relies on the gut microbiota. Science 2015;350(6264):1079-84. 3. Caporaso JG, et al., QIIME allows analysis of high-throughput community sequencing data. Nat Methods. 2010;7(5):335-6.

Citation Format: Jia Xue, Zhun Wang, Sheng Guo, Jie Cai, Davy Ouyang, Bin Cai, Gang Chen, Jie Liu, Xin Dong, Henry Li. Intestinal microbiota may dynamically facilitate the anti-PD-L1 immunotherapy [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 2008. doi:10.1158/1538-7445.AM2017-2008
Abstract 2010: BTK inhibitor BGB-3111 demonstrates anti-tumor activity in solid tumor models
Authors: Hu Nan , Zhang Jiye , He Min , Zhang Shuo , Liu Yong , Wang Lai
Published: July 2017

Background BGB-3111 is a novel, irreversible, second generation BTK inhibitor with better selectivity profile and DMPK property compared to ibrutinib. It has demonstrated promising anti-tumor activities in patients with advanced B cell malignancies. Given BTK is expressed in all hematopoietic lineages except for T lymphocytes, it is reasonable to explore the immune modulatory effect of BGB-3111. In this study, we sought to investigate the anti-tumor activity of BGB-3111 in solid tumor models.

Methods Cell viability was assessed with Cell Titer Glo® assay and half maximal inhibitory concentrations (IC50) were estimated. In vivo activity was assessed in subcutaneous mouse xenograft models. Treatments were administered by oral gavage and individual body weight and tumor volume was recorded twice weekly.

Results In vitro studies showed that MDA-MB-436 cells are insensitive to BGB-3111, which do not expresse BTK. In both human breast cancer MDA-MB-436 and human A431 epidermoid carcinoma subcutaneous xenograft models, the tumor cells were co-injected with peripheral blood mononuclear cells (PBMCs) of healthy donors. In MDA-MB-436 model, BGB-3111 (15 mg/kg, BID) single agent significantly induced tumor growth inhibition (TGI) of 55%, whereas showed no anti-tumor effect if no PBMCs co-injected. Furthermore, co-treatment of BGB-3111 (15 mg/kg, BID) and anti-PD-1 antibody BGB-A317 (10 mg/kg, QW) demonstrated enhanced therapeutic effect in A431 allogeneic model. Interestingly, in BCLU200 and BCLU054 NSCLC primary tumor xenograft models (without PBMC co-injection), BGB-3111 (15 mg/kg, BID) also demonstrated significant anti-tumor activity.

Conclusions In summary, BGB-3111 showed interesting activity in solid tumor models, suggesting BTK inhibitor might have potential to be used beyond hematology malignancies. .

Citation Format: Nan Hu, Jiye Zhang, Min He, Shuo Zhang, Yong Liu, Lai Wang. BTK inhibitor BGB-3111 demonstrates anti-tumor activity in solid tumor models [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 2010. doi:10.1158/1538-7445.AM2017-2010
Abstract 2012: UVB-induced ULBP1 upregulation in melanocytes depends on HMGB1-mediated activation of NF-κB and IRF3
Authors: Wu Zhaohui , Wang Wei
Published: July 2017

Anti-tumor immune surveillance mediated by innate immunity cells such as NK cells plays a critical role in eliminating “damaged” cells at precancerous stage and preventing cancer progression. As a key epidemiological factor associated with melanoma, solar UV radiation also elicit immunosurveillance by upregulating ligands for NK cell activating receptor NKG2D. Nevertheless, how UVR upregulates NKG2DL in melanocytes is not completely understood. We found UVB exposure induced secretion of damage-associated molecular patterns molecule HMGB1 from skin cells. HMGB1 activates transcription factors NF-κB and IRF3 in melanocytes which synergistically enhances NKG2D ligand ULBP1 transcription. Moreover, RAGE is essential for HMGB1-induced activation of NF-κB and IRF3, which serves as the HMGB1 receptor and mediates activation of TBK1. Consistently, HMGB1 deficient melanoma cells are less susceptible to NK cells mediated cytotoxicity. Our study provides a mechanistic link between environmental UV radiation and antitumor immunosurveillance induced in melanocytes, which may play a critical role in the early stages of melanomagenesis.

Citation Format: Zhaohui Wu, Wei Wang. UVB-induced ULBP1 upregulation in melanocytes depends on HMGB1-mediated activation of NF-κB and IRF3 [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 2012. doi:10.1158/1538-7445.AM2017-2012
Abstract 2021: Ablation of caspase-7 promotes solar-simulated light-induced mouse skin carcinogenesis through upregulation of keratin-17
Authors: Lee Mee-Hyun , Lim Do Young , Lee Sung Young , Shim Jung Hyun , Liu Xuejiao , Zhao Ran , Huang Hai , Bowden G.Timothy , Surh Young-Joon , Cho Yong-Yeon , Bode Ann M. , Dong Zigang
Published: July 2017

Solar UV irradiation is an environmental carcinogen that causes skin cancer. Caspase-7 is expressed at reduced levels in many cancers. The present study was designed to examine the role of caspase-7 in solar-simulated light (SSL)-induced skin cancerr and to elucidate its underlying molecular mechanisms. Our study revealed that mice with genetic ablation of caspase-7 are significantly susceptible to SSL-induced skin carcinogenesis. Epidermal hyperplasia, tumor volume and tumor numbers were increased in caspase-7 knockout (KO) mice compared with SKH1 wild-type mice irradiated with SSL. The expression of cell proliferation biomarkers, such as survivin and Ki-67, was elevated in SSL-irradiated skin of caspase-7 KO mice compared with those observed in SSL-exposed wild-type SKH1 mouse skin. Moreover, SSL-induced apoptosis was abolished in skin from caspase-7 KO mice. 2-DE gel electrophoresis, followed by matrix-assisted laser desorption/ionization-time-of-flight analysis of skin tissue lysates from SSL-irradiated SKH1 wild-type and caspase-7 KO mice revealed an aberrant induction of keratin-17 in caspase-7 KO mice. Immunohistochemical analysis of skin tumors also showed an increase of keratin-17 expression in caspase-7 KO mice compared with SKH1 wild-type mice. Furthermore the expression of keratin-17 was also elevated in SSL-irradiated caspase-7 KO keratinocytes as well as in human basal cell carcinomas. The in vitro caspase activity assay showed keratin-17 as a substrate of caspase-7, but not caspase-3. Overall, our study suggests that genetic loss of caspase-7 promotes SSL-induced skin carcinogenesis by blocking caspase-7-mediated cleavage of keratin-17.

Citation Format: Mee-Hyun Lee, Do Young Lim, Sung Young Lee, Jung Hyun Shim, Xuejiao Liu, Ran Zhao, Hai Huang, G.Timothy Bowden, Young-Joon Surh, Yong-Yeon Cho, Ann M. Bode, Zigang Dong. Ablation of caspase-7 promotes solar-simulated light-induced mouse skin carcinogenesis through upregulation of keratin-17 [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 2021. doi:10.1158/1538-7445.AM2017-2021
Abstract 2025: A distinct role of RhoB in simvastatin-induced cytotoxicity in breast cancer cells
Authors: Seah Serena , Wang Tingting , Lee Soo Chin
Published: July 2017

Purpose Statins, a class of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors, are initially developed as cholesterol-lowering drugs by inhibiting the mevalonate pathway. They have recently gained attention for their potential anticancer properties, but the mechanisms of their anticancer effects remain elusive. This study aims to investigate the antiproliferative effects of statins in breast cancer cell lines.

Methods We screened a panel of breast cancer cell lines (Estrogen receptor positive (ER+): CAMA1, MCF7, T47D, ZR-75-1 and Hcc1428; triple negative (TNBC): MDA MB231, MDA MB468, BT549, Hs578T and Hcc1806) and assessed the sensitivity of these cells to simvastatin in relation to their hormone receptor status using cell proliferation assay. Next, to elucidate the mechanisms underlying simvastatin sensitivity, we evaluated the (i) expression of key enzymes in the mevalonate pathway using qPCR and western blot analysis and (ii) the role of sterol biosynthesis metabolites by exogenously adding these compounds and testing their effects on simvastatin-induced cytotoxicity. Finally, we performed functional assays following siRNA knockout to identify the key small GTPase involved.

Results We found TNBC cell lines to be more susceptible to simvastatin compared to ER+ cell lines (mean IC50 of 7.98μM [95%CI 2.75-13.22] versus 41.74μM [95%CI 6.71-76.78]). Simvastatin treatment induced robust apoptosis in TNBC but not the ER+ cells. There was no significant difference in mRNA expression of HMGCR, HMGCS, MVK, MVD, IDI1 enzymes involved in the mevalonate pathway between TNBC and ER+ breast cancer cell lines. Supplementation with geranylgeranyl pyrophosphate but not farnesyl pyrophosphate, inhibited simvastatin-mediated cell death, suggesting the involvement of geranylgeranylated proteins such as Rho family of GTPases. Here, we identified RhoB to be a key player in simvastatin-mediated cytotoxicity. RhoB showed a significant increase in transcript and protein levels in response to simvastatin treatment in the TNBC cells. Interestingly, the increase in protein expression was not associated with an increase in its prenylation as the accumulation of RhoB was observed only in the cytosolic fraction. Finally, silencing RhoB was able to abrogate the cytotoxic effects mediated by simvastatin in TNBC cells.

Conclusions Taken together, our data reveals a critical role of RhoB in the anticancer activity of simvastatin, which appears to be exclusive to TNBC cells suggesting that HMG-CoA reductase inhibitors may provide new therapeutic strategies for TNBC treatment.

Citation Format: Serena Seah, Tingting Wang, Soo Chin Lee. A distinct role of RhoB in simvastatin-induced cytotoxicity in breast 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 2025. doi:10.1158/1538-7445.AM2017-2025
Abstract 2028A: Glutamine deprivation-elicited sensitization of multiple myeloma to venetoclax is associated with electron transport chain inhibition
Authors: Bajpai Richa , Wei Changyong , Shanmugam Mala
Published: July 2017

Cancer cells exhibit altered glucose and glutamine metabolism to sustain survival and proliferation. Altered nutrient utilization also contributes to the development of resistance to apoptosis via regulation of pro and anti-apoptotic BCL-2 family members. We previously reported that glutamine deprivation enhanced binding of BIM to BCL-2 thereby sensitizing myeloma cell lines and patient samples to Venetoclax (ABT-199). In this study we investigated the metabolites regulated by glutamine withdrawal that contribute to enhanced BIM-BCL-2 association and ABT-199 sensitivity. Metabolite profiling and isotope tracing flux analyses of glutamine deprived myeloma cell lines revealed specific reduction of TCA cycle metabolites including succinate, that were not maintained by glucose present in the medium. Cellular bioenergetics end points i.e. OCR and ATP were also suppressed upon glutamine withdrawal correlating with a suppression of the TCA cycle and oxidative phosphorylation. Supplementation of cell permeant dimethyl-α-ketoglutarate (DMK), a TCA cycle metabolite derived from glutaminolysis, to glutamine deprived cells reversed sensitivity to ABT-199. This ability of DMK to reverse ABT-199 sensitization in glutamine deprived cells was associated with a replenishment of TCA cycle intermediates without restoration of ATP levels. Therefore, we sought to further interrogate the TCA cycle and electron transport chain (ETC) in facilitating glutamine withdrawal-associated ABT-199 sensitization. TCA cycle metabolites are linked to mitochondrial respiration through ETC complexes. Inhibition of ETC complexes I, II, III or V in myeloma cell lines enforced similar effects as glutamine deprivation and sensitized cells to ABT-199. Among all five complexes, complex II is more explicitly linked with the TCA cycle through succinate dehydrogenase (SDH). SDH facilitates the oxidation of succinate to fumarate in the TCA cycle through its subunit SDHA, and transfers the released electrons to ubiquinone via its SDHB, C and D subunits supporting the ETC activity of complex II. Competitive inhibition of succinate dehydrogenase by 3-nitro propionic acid (3NPA) induced BIM expression and sensitized myeloma cells to ABT-199, similar to that detected upon glutamine deprivation. Our observations thus narrow down a role for ETC inhibition in facilitating ABT-199 sensitivity and underscore the importance of further interrogation of ways to metabolically perturb and sensitize cancer cells to the highly potent BH3 mimetic ABT-199.

Citation Format: Richa Bajpai, Changyong Wei, Mala Shanmugam. Glutamine deprivation-elicited sensitization of multiple myeloma to venetoclax is associated with electron transport chain inhibition [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 2028A. doi:10.1158/1538-7445.AM2017-2028A
Abstract 2033: Testing the combined effects of low dose olaparib plus ibrutinib on MCL cytotoxicity
Authors: Curtis Adam D. , Hoffert Todd A. , Rajan Sheila S. , Rueter Jens , Shopland Lindsay S.
Published: July 2017

Mantle cell lymphoma (MCL) presents a therapeutic challenge, with frequent relapses after therapy due to high levels of DNA damage and disease evolution. One currently approved MCL therapeutic, ibrutinib, is a tissue-specific agent with relatively few adverse effects. However, ibrutinib is administered at high dose for MCL and provides only a short progression-free survival time. To potentially improve ibrutinib therapy for MCL, we tested the effects of combining ibrutinib with the DNA damage response inhibitor, olaparib, on MCL cells in vitro. We confirmed that ibrutinib monotherapy is cytotoxic to MCL cell lines only at high doses (> 25 μM). In contrast, single-agent olaparib treatment is cytotoxic at lower concentrations (10 μM). Importantly, the addition of low dose olaparib to ibrutinib has an additive cytotoxic effect. Notably, the effects of ibrutinib alone and in combination are dependent on cell medium composition. Our findings support clinical testing of ibrutinib plus olaparib therapy to reduce MCL cell burden initially and to potentially slow MCL cell evolution in the longer term. Our data also suggest the possibility for more effective ibrutinib-based therapy via manipulation of the MCL cell niche.

Citation Format: Adam D. Curtis, Todd A. Hoffert, Sheila S. Rajan, Jens Rueter, Lindsay S. Shopland. Testing the combined effects of low dose olaparib plus ibrutinib on MCL cytotoxicity [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 2033. doi:10.1158/1538-7445.AM2017-2033
Abstract 204: In vitro metabolomics of mesothelioma: Challenges and outcomes
Authors: Lagniau Sabrina , Lamote Kevin , Vandermeersch Lore , Langenhove Herman Van , Meerbeeck Jan P. van , Vermaelen Karim Y.
Published: July 2017

Introduction

Early detection of malignant pleural mesothelioma (MPM) is likely to improve outcome in affected patients. From our previous studies (MesoBreath 1 & 2) we developed a screening tool in which volatile organic compounds (VOCs) in breath allowed discrimination of MPM patients from at risk controls. However it is not yet clear which VOCs arise from the neoplastic cells themselves or from the host response. Identifying the cancer cell-specific compounds should increase the specificity of our breathomic signature model. Therefore, we set up an in vitro experimental setup model for VOC analysis from the headspace of mesothelioma cell lines.

Methods

Standard polystyrene culture flasks (NunclonTM Delta Surface, Thermo Scientific) were mounted with an adapted cap accommodating teflon inlet and outlet tubes. The inlet tube provides environmental air while an external pump (Gilian GilAir Plus, Sensidyne) draws headspace air from the outlet tube over an adsorption column (Tenax GR, Markes International, UK). The adsorption columns were further processed on a GC-MS platform (GC: Focus GC, Thermo Finnigan, Milan, Italy; DSQII Single Quadrupole MS, Thermo Finnigan, Austin, TX, USA). VOC profiles were processed using supervised clustering algorithms and principal component analysis.

Results

Using this setup, we have investigated the impact of flow and total sampled volume on the concentration and range of VOCs detected. For a constant flow, VOCs were detected in higher concentrations with increasing sample volume. For a constant volume, a lower sampling flow yielded a higher concentration of detected VOCs. Most of the VOCs obtained were alkanes and ketones. We will show data illustrating the differential VOC profiles of container plastic, cell culture medium and growing mesothelioma cancer cells, as well as the differential VOC output of epithelioid vs sarcomatoid mesothelioma cell lines.

Conclusions

We have succesfully developed an in vitro experimental setup allowing collection and analysis of VOCs emanating from mesothelioma cancer cell line cultures. This platform will allow us to investigate how VOC profiles are impacted in different experimental conditions (e.g. hypoxia, nutrient deprivation, cytostatics, co-culture with leukocytes). The data collected will help us to pinpoint the cancer cell-derived VOCs from patient exhaled breath, and increase the robustness of our mesothelioma breathomic signature.

Note: This abstract was not presented at the meeting.

Citation Format: Sabrina Lagniau, Kevin Lamote, Lore Vandermeersch, Herman Van Langenhove, Jan P. van Meerbeeck, Karim Y. Vermaelen. In vitro metabolomics of mesothelioma: Challenges and outcomes [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 204. doi:10.1158/1538-7445.AM2017-204
Abstract 2041: High-throughput chemical screening for sensitization of bladder cancer to gemcitabine and cisplatin chemotherapy
Authors: Kita Yuki , Kobayashi Takashi , Saito Ryouichi , Yamasaki Toshinari , Inoue Takahiro , Ogawa Osamu
Published: July 2017

Introduction and Objectives Gemcitabine and cisplatin chemotherapy (GC) is the current standard regimen for locally advanced and metastatic bladder cancer (BC). Despite a relatively high initial response rate, some cases do not regress (intrinsic resistance) and the remaining cases often show regrowth after initial shrinkage (acquired resistance). To identify novel therapeutic agents for overcoming these resistances, we applied a high-throughput screening of chemicals administered in combination with GC.

Methods As a high-throughput screening, 2100 compounds were administered alone or in combination with GC to human BC cell lines (J82, UMUC-3). Cell viability was determined after 3-day incubation and chemicals that enhanced inhibitory effect of GC were screened. The in vivo effect of disulfiram (DSF) was studied in UMUC-3 cell xenografts, and western blot, immunofluorescence, induced coupled plasma spectrometry and measurement of reactive oxygen species (ROS) were done in vitro for mechanistic exploration.

Results The initial screening identified 26 compounds and further validation narrowed them into the most synergistic agent DSF, an FDA-approved drug for alcoholism. Combination index assay showed synergistic effects of DSF with cisplatin but not with gemcitabine in J82, UMUC-3, T24, HT1197 and HT1376 cells. Co-administration of DSF significantly increased DNA-platinum adducts by regulating cisplatin efflux transporter ATP7A and enhanced apoptosis by GC treatment in UMUC-3 cells, with significant increase of ROS production. Use of DSF in combination with GC (GCD) significantly inhibited tumor growth of UMUC-3 subcutaneous xenograft on athymic mice (by 39% compared with GC alone, p = 0.02). GCD regimen was as tolerable as GC and no significant differences were observed in body weight of treated mice between the two regimens.

Conclusions Repositioning of DSF to a chemotherapy sensitizer is a promising treatment strategy, which can be translated rapidly in the future.

Citation Format: Yuki Kita, Takashi Kobayashi, Ryouichi Saito, Toshinari Yamasaki, Takahiro Inoue, Osamu Ogawa. High-throughput chemical screening for sensitization of bladder cancer to gemcitabine and cisplatin chemotherapy [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 2041. doi:10.1158/1538-7445.AM2017-2041
Abstract 2060: Characterizing acquired resistance to palbociclib in breast cancer
Authors: Vijayaraghavan Smruthi , Doostan Iman , Carey Jason P.W. , Keyomarsi Khandan
Published: July 2017

The CDK4/6 inhibitor palbociclib is currently being used in combination with endocrine therapy to treat advanced ER positive breast cancer patients. While this treatment has shown great promise in the clinic, about 25% of the patients do not respond, and almost all patients eventually acquire resistance to palbociclib treatment. Hence, understanding the mechanism(s) of acquired resistance to CDK4/6 inhibition is crucial to devise alternate treatment strategies. To interrogate this, we developed MCF7 and T47D resistant cells by treating them with increasing doses of palbociclib over a 6-month period. After confirming that these cells were resistant to palbociclib, we performed genome-wide expression analysis via RNA-seq, in comparison with the parental (sensitive) cells. RNA- seq analysis revealed 2888 differentially expressed genes (p<0.05) in the resistant cells when compared to parental. Further, gene set enrichment analysis (GSEA) revealed enrichment of immune pathways (interferon alpha and gamma response, immune response) and pathways known to regulate EMT and cancer stem cells (IL-6/Stat3, IL-2/STAT-5, Notch, Wnt) in the resistant cells. Additionally, GSEA analysis revealed downregulation of G2/M checkpoint, estrogen response and DNA repair pathways (double strand break repair). Thus, this data suggests that combined targeting of two or more pathways that are altered in the resistant cells can provide a novel therapeutic strategy to combat CDK4/6 inhibitor resistance.

Citation Format: Smruthi Vijayaraghavan, Iman Doostan, Jason P.W. Carey, Khandan Keyomarsi. Characterizing acquired resistance to palbociclib 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 2060. doi:10.1158/1538-7445.AM2017-2060
Abstract 2066: Delivery of 2`F-PS2 PTGER3 siRNA-DOPC enhances anti-tumoral activity in cisplatin resistant ovarian cancer model
Authors: Bayraktar Emine , Rodriguez-Aguayo Cristian , Siddik Zahid , Lopez-Berestein Gabriel
Published: July 2017

RNAi-based therapeutics approaches holds a big promise for clinical translation. However, siRNAs are very weak and highly susceptible to degradation by nucleases. Nanoparticle delivery systems and chemical modifications of small interfering RNA (siRNA) can enhance efficient intracellular delivery and resistance to degradation for various siRNAs resulting in an increase in their clinical therapeutic potential. Here, we hypothesized that DOPC nanoparticles incorporated with a chemically fluoro phosphorodithioate (2`F-PS2) modified-PTGER3 siRNA will enhance the stability, prolong the silencing effect in vitro and increase the anti-tumoral effect when is combined with cisplatin in vivo. We screened 51 different chemically modified PTGER3-siRNAs which have 2'-F-PS2 or 2'-O-methyl modification on selectively protected nuclease-sensitive sites. We determined PTGER3 gene expression after siRNA-2'-F-PS2 or 2'-O-methyl modified mediated silencing, stability, time-response silencing effect and the therapeutic effect in xenograft OC in vivo model. We demonstrated that siRNA-2'-F-PS2 prolong the stability for more than 24 hours and enhance the silencing for more than 96 hours. Moreover, we found that PTGER3-silencing effect can control the expression of CFTR multidrug resistant pump by regulating ERK-ELK1-ETS1-CFTR axis, resulting in an increase of the cisplatin uptake, decreased the tumor-associated angiogenesis and tumor growth in xenograft OC in vivo model. SiRNA-PTGER3-2'-F-PS2 modification increase the stability and time-response silencing effect, leading to a synergistic anti-tumor in combination with cisplatin in ovarian cancer models.

Citation Format: Emine Bayraktar, Cristian Rodriguez-Aguayo, Zahid Siddik, Gabriel Lopez-Berestein. Delivery of 2`F-PS2 PTGER3 siRNA-DOPC enhances anti-tumoral activity in cisplatin resistant ovarian cancer model [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 2066. doi:10.1158/1538-7445.AM2017-2066
Abstract 2068: Development of a rational triple combination therapy for castration-resistant prostate cancer
Authors: Qiao Yuanyuan , Morgan Todd M. , Chinnaiyan Arul M.
Published: July 2017

Background The androgen receptor (AR) signaling pathway drives prostate cancer development and progression, making it a major target for drug development. However, resistance to AR targeted therapies invariably develops and eventually leads to an aggressive, castrate-resistant prostate cancer (CRPC). Although CRPC often remains dependent on AR signaling, anti-androgen therapies can lead to the development of AR independent disease and metastatic CRPC. Understanding the molecular basis of this transition and resistance to current anti-androgen therapy will provide important insight and reveal novel therapeutic strategies for both AR-positive and -negative disease pathways.

Methods and Results We analyzed in silico data of AR (signaling)-positive or -negative human CRPC tissue samples and discovered that MET expression is specifically increased only in AR-negative CRPC samples. When AR-positive CRPC models are subjected to AR signaling inhibition (by the AR antagonist enzalutamide or androgen deprivation), MET is increased and susceptible to activation by its ligand HGF. Therefore, we postulate that dual targeting of AR and MET signaling pathways may be a better approach to prevent and overcome resistance-related disease progression. Our preliminary AR ChIP-seq data suggested that MET transcription is not affected by AR directly rather, MET protein is modulated by AR signaling at the post-translational level. Therefore, we hypothesize that a combination therapy of a proteasome inhibitor and MET inhibitor may have potential therapeutic benefit for some CRPC patients. By using in vitro and in vivo models of AR-dependent CRPC, we have showed that combination of the dual MET/VEGFR2 inhibitor cabozantinib and enzalutamide treatment is more efficacious than either inhibitor alone. In addition, Bortezomib, an FDA-approved proteasome inhibitor, showed significant synergistic effect when paired with cabozantinib in our preliminary data using in vitro and in vivo CRPC models. In vitro results suggest that triple combination of anti-androgen, MET inhibitor and proteasome inhibitor therapies will maximize inhibition in CRPC.

Conclusion MET is a compensatory survival pathway in AR+ CRPC upon anti-androgen therapy. The rational for triple combination of anti-androgen, MET inhibitor and proteasome inhibitor therapies is a feasible approach to maximize inhibition in CRPC while minimizing development of drug resistance to any single agent.

Citation Format: Yuanyuan Qiao, Todd M. Morgan, Arul M. Chinnaiyan. Development of a rational triple combination therapy for castration-resistant prostate 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 2068. doi:10.1158/1538-7445.AM2017-2068