bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 1679: Interference of PD-1 and PD-L1 interaction with small-molecule inhibitors enhances the efficacy of tumor-specific CTLs
Authors: Redd Priscilla S. , Lu Chunwan , Ostrov David , Lebedyeva Iryna , Liu Kebin
Published: August 2018

Programmed cell death-1 (PD-1) is an immunosuppressive receptor expressed on T cells upon activation. Once interacting with its ligands, programmed death ligand-1 (PD-L1), the PD-1:PD-L pathway curbs T cell activation and thereby serves as a natural protection mechanism against autoimmunity. However, this pathway has been hijacked by cancer cells in order to evade the immune system. In fact, PD-L1 is commonly overexpressed on the surface of tumor cells as well as other cells in the tumor microenvironment, such as myeloid-derived suppressor cells. This interface has already been recognized as an effective target for cancer therapy. Blocking the PD-1:PD-L axis would unleash T cells from suppression to maintain their effector function against tumor cells. At least two anti-PD-1 and three anti-PD-L1 blocking antibodies have been approved for human cancer immunotherapy. However, these drugs are only successful in a small number of cancers. Therefore, developing inhibitors that block this axis more effectively and have a wider scale of impact is necessary. We used a molecular docking model and performed virtual chemical library screening to identify small molecule inhibitors of PD-1 and PD-L1 interactions. To this end, we have identified 175 PD-L1 small molecule inhibitors. Functional assays were established with the 4T1 murine breast cancer cell line and a tumor-specific murine T cell line in the presence or absence of the PD-L1 small molecule inhibitors to test if these small molecule PD-L1 inhibitors can increase T cell killing of tumor cells. Cell viability assays were also done to test the toxicity of these inhibitors on tumor cells in the absence of T cells. From these studies, we have identified ten novel PD-L1 small molecule inhibitors that can significantly increase the lytic activity of the tumor-specific cytotoxic T lymphocytes (CTLs) to kill 4T1 tumor cells. These ten PD-L1 small molecule inhibitors show little to no cytotoxicity to 4T1 tumor cells in the absence of the antigen-specific T cells, suggesting that these small molecule inhibitors themselves are not cytotoxic, and therefore are potentially safe as therapeutic agents. These proof of concept studies indicate that these small molecule inhibitors are potentially potent agents for blocking PD-1 and PD-L1 interaction in cancer immunotherapy.

Citation Format: Priscilla S. Redd, Chunwan Lu, David Ostrov, Iryna Lebedyeva, Kebin Liu. Interference of PD-1 and PD-L1 interaction with small-molecule inhibitors enhances the efficacy of tumor-specific CTLs [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 1679.
Abstract 1709: Enhanced proliferation and effector functions of human immune cells in response to immune checkpoint therapy of MDA-MB-231 tumor bearing huNOG mice engrafted with human CD34+ cells
Authors: Bui Thi , Shinn Karyn McArtan , O'Koren Emily G. , Derrick Ashleigh , Godfrey Beverly , Belle Ian , Davis Jason , Synnott Aidan , Avrutskaya Anya , Marval Paula L. Miliani De
Published: August 2018

Given the recent success of cancer immunotherapies, well characterized pre-clinical models are needed to enable drug discovery efforts. The recently developed humanized mouse models composed of various types of immune cells offer a unique tool to evaluate aspects of the human immune system in response to immunotherapy. MDA-MB231 cells express high levels of the T-inhibitory molecule PD-L1 making this breast cancer line an ideal candidate for testing the efficacy of the immune-checkpoint inhibitors pembrolizumab (anti-PD-1) and ipilimumab (anti-CTLA-4) in the CD34+ huNOG humanized mouse strain. We analyzed the distribution of CD4 and CD8 T lymphocytes, Treg cells, NK cells and B cells in blood, spleen and tumor samples from MDA-MB231 tumor bearing huNOG humanized treated-mice via flow cytometry. We found that combination therapy enhanced the effector functions of CD4+ and CD8+ T cells associated with increased expression of IFN-gamma and Granzyme B. Supporting this data, we observed an increase in Ki-67+ cells which correlates with a decrease in PD-1 expression in response to pembrolizumab therapy associated with activation of T lymphocytes. In summary, these results demonstrate the potential of humanized mouse models to evaluate the anti-tumor activity of human immune cells in a preclinical setting in response to human specific immune checkpoint targeted therapies.

Citation Format: Thi Bui, Karyn McArtan Shinn, Emily G. O'Koren, Ashleigh Derrick, Beverly Godfrey, Ian Belle, Jason Davis, Aidan Synnott, Anya Avrutskaya, Paula L. Miliani De Marval. Enhanced proliferation and effector functions of human immune cells in response to immune checkpoint therapy of MDA-MB-231 tumor bearing huNOG mice engrafted with human CD34+ cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 1709.
Abstract 1720: Analysis of multiplexed immunotherapy targets and secreted ligands using computational tumor microenvironment profiling
Authors: Caldara Jenifer , Hirsch Brooke , Krueger Joseph , Bunker Chris , Kim Jeff , Laeremans Annelies , Qutaish Mohammed , Harney Allison
Published: August 2018

As the number and diversity of cellular and signaling pathway therapeutic targets in immuno-oncology increases, more therapy combinations are aimed at multiple cell types in the tumor microenvironment (TME). To develop rational combinations of therapies that will be effective in any individual patient, multivariate biomarker assays will be required to understand each patient's specific tumor and immune profile. Understanding the mechanistic effects of immunotherapy includes the tissue context of direct immunotherapy targets and downstream effector molecules such as secreted cytokines. Although the content of tumor-infiltrating immune cells and gene expression of the total tumor can be ascertained through several methods, spatial arrangements and proximity of cells and co-localization of biomarkers can only be achieved with tissue-based assays. Duplex chromogenic in situ hybridization assays using the RNAscope platform allows for the visualization of gene expression of mRNA targets directly in tissue for multiple cell types or biomarkers. Computational Tissue Analysis (cTA™) was used to quantify cellular spatial distributions including regional density maps, proximity measurements, and colocalization of biomarkers in both the tumor nests and the surrounding stroma that would be challenging by visual inspection of duplex RNAscope assays in non-small cell lung cancer (NSCLC) tissue microarrays (TMAs). Often, neither immune effector cells nor the therapeutic target is sufficient in isolation to understand blocked anti-tumor immune responses and therefore the potential efficacy of a single or combination therapeutic strategy. Multiplex RNAscope assays and cTA™ in combination allow the assessment of end points that measure spatial relationships between cell types expressing certain biomarkers. As these are performed in the context of the tissue microarchitecture within and across multiple tissue sections, they are a significant advancement over traditional tissue-based manual end points.

Citation Format: Jenifer Caldara, Brooke Hirsch, Joseph Krueger, Chris Bunker, Jeff Kim, Annelies Laeremans, Mohammed Qutaish, Allison Harney. Analysis of multiplexed immunotherapy targets and secreted ligands using computational tumor microenvironment profiling [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 1720.
Abstract 173: Adipocytes-derived collagen reorganization in microenvironment promotes breast cancer progression
Authors: Xiaohui Wei , Jinyong He , Sijing Li , Shengtao Yuan , Li Sun
Published: August 2018

Purposes

Breast cancer cells recruit surrounding stromal cells, such as cancer-associated fibroblasts (CAFs), to reorganize collagen and promote tumor metastasis. Adipocytes are the most abundant stromal partners in breast tissue, whether cancer-associated adipocytes (CAAs) involve in the collagen reorganization and ultimately promoting metastasis of breast cancer is still unknown. In this study, we seek to understand whether adipocytes involve in the extracellular matrix collagen reorganization in breast cancer and its underline mechanism.

Methodology

In vitro mature adipocytes and breast cancer transwell co-culture model and orthotopic xenograft mouse model of human breast tumor formation in vivo were used to study the crosstalk between adipocytes and breast cancer cells, and then using a combination of proteomics, database analysis and clinical breast cancer samples analysis to study the mechanism mediated adipocytes-derived collagen reorganization.

Results

Here, we found that CAAs co-cultured with breast cancer cells increased the linearly aligned type I collagen fibers deposition in vitro and in vivo, which accompanied with increasing collagen lysyl hydroxylation 2 (LH2) and lysyl oxidase (LOX) expression. Breast cancer cells migrated orderly along the CAAs-derived collagen, while randomly migrated through the mature adipocyte-derived collagen. Simultaneously, clinical breast cancer samples analysis showed LH2 was high expression in the areas where cancer cells infiltrated into fatty tissue, which accompanied with poor prognosis. It is well-known that interaction between adipocytes and cancer altered the secretion of cytokines. In the present study, proteomics analysis showed that IL-6, MIF-1, TECK, MCP-1, PAI-1, IGFBP-1, TIMP1 and TIMP2 are highly secreted in adipocytes-breast cancer system. And using agonist or antagonist of these cytokines showed that these cytokines might involve in the reorganization of adipocyte-derived collagen. Mechanistic investigations demonstrated PI3K/AKT pathway and JAK/STAT3 signaling pathway involved in the rearrangement of adipocyte-derived collagen, which mediated by promoting forkhead-box(FOX) and phosphorylation STAT3(p-STAT3) translocate to the nucleus, respectively. Moreover, FOX and STAT3-dependent induction of LH2 expression further potentiated the adipocytes-derived collagen reorganization, which thus promoting breast cancer metastasis.

Conclusion

Collectively, our findings reveal new insights underlying increased breast cancer progression and offer new opportunities for stromal-targeted therapies in breast cancer.

Citation Format: Wei Xiaohui, He Jinyong, Li Sijing, Yuan Shengtao, Sun Li. Adipocytes-derived collagen reorganization in microenvironment promotes breast cancer progression [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 173.
Abstract 1739: Tumor extracellular vesicles are required for tumor-associated macrophage programming
Authors: Rabe Daniel C. , Lee Jiyoung , Rustandy Felicia , Rosner Marsha R.
Published: August 2018

Triple-negative breast cancers (TNBC) are highly infiltrated by tumor-associated macrophages (TAMs) that promote tumor growth, survival, metastasis and therapeutic resistance. Although cytokines such as CCL5 have been implicated in TAM recruitment to TNBC tumors, the mechanism by which tumor cells educate TAMs is not understood. Here we show that tumor extracellular vesicles (EVs) are both necessary and sufficient for programming TAMs toward a pro-metastatic phenotype. The mechanism involves CCL5 regulation of tumor EVs, which activate TLR2 and TLR3, leading to secretion of a common set of cytokines that further stimulate tumor cell invasion and metastasis as well as alter the tumor microenvironment. Cytokine expression is significantly correlated to CCL5 expression and up-regulated in TNBC patient tumors. These results demonstrate for the first time that tumor EVs are key mediators of TAM education, phenocopy the pro-metastatic and drug resistant state of the tumors to TAMs, and illustrate the potential clinical relevance of these findings to TNBC patients.

Citation Format: Daniel C. Rabe, Jiyoung Lee, Felicia Rustandy, Marsha R. Rosner. Tumor extracellular vesicles are required for tumor-associated macrophage programming [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 1739.
Abstract 1755: PEGylated adenosine deaminase (ADA2) prevents adenosine-mediated increase in tumor growth and improves antitumor immune responses
Authors: Londoño-R Luz Marina , Cowell Jessica , Wang Lin , Zhao Qiping , Huang Lei , Thanos Chris , LaBarre Michael J. , Li Xiaoming , Cekic Caglar
Published: August 2018

Adenosine deaminase 2 (ADA2) is a human serum protein that catalyzes the reaction of deamination of adenosine to inosine. Besides catalytic activity, ADA2 has a heparin-binding domain and a growth factor-like domain. Adenosine accumulates in the tumor microenvironment and suppresses anti-tumor immune responses, while promoting tumor cell metastasis. Previously, we showed that treatment of mice with PEGylated forms of ADA2 (PEG ADA2) can decrease the accumulation of tumor-associated adenosine. Here, we analyzed the TCGA RNA-seq database using OncoLnc tool and observed that high expression of the ADA2 gene (CECR1) in certain immunotherapy responsive tumors correlated with increased survival of patients. We then tested different engineered ADA2 variants, using the inactive enzyme variant as a control, for the reversal of adenosine-mediated responses in human T cells, mouse peritoneal macrophages, and mouse and human tumor cell lines. ADA2 variants with higher catalytic activity were able to reverse adenosine-mediated suppression of human T-cell proliferation, cAMP accumulation in tumors and human T cells, and polarization of macrophages into an immunosuppressive, pro-tumor phenotype, whereas the inactive ADA2 variant failed to cause any of these effects. In addition, the variant that lacks the ability to bind to heparin but has improved catalytic activity (PEG NME8058) showed similar responses to those with the catalytically improved variant with intact heparin-binding domain (PEG NME8062). These results suggest that the improved immune cell activity with ADA2 in the presence of adenosine requires the enzyme activity of this molecule. Next, we assessed PEG NME8062 in MC38 and CT26 colon carcinoma syngeneic tumors in C57BL/6 and Balb/c mice, and observed delayed growth in both tumors. Using the inactive enzyme variant, we have shown that anti-tumor effect of PEG NME8062 depends on enzyme activity. Delayed tumor growth was also associated with increased density of key anti-tumor immune cell populations in both tumor models. These data suggest that PEG ADA2 can reduce tumor growth in an enzyme-activity-dependent manner and promote anti-tumor immune responses in vitro and in vivo. These findings have important implications for targeting purinergic signaling for cancer therapy.

Citation Format: Luz Marina Londoño-R, Jessica Cowell, Lin Wang, Qiping Zhao, Lei Huang, Chris Thanos, Michael J. LaBarre, Xiaoming Li, Caglar Cekic. PEGylated adenosine deaminase (ADA2) prevents adenosine-mediated increase in tumor growth and improves antitumor immune responses [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 1755.
Abstract 1764: Neurovascular-targeting antibodies discovered using yeast biopanning enhance drug delivery and improve survival for glioblastoma
Authors: Clark Paul A. , Umlauf Benjamin J. , Shusta Eric V. , Kuo John S.
Published: August 2018

INTRODUCTION: Median survival for newly diagnosed glioblastoma (GBM) patients remains less than two years despite aggressive clinical interventions. Antibody-based GBM-targeting could improve brain delivery and accumulation of therapies, but it has been challenging to identify universal tumor cell antigens due to intra-tumor and inter-patient GBM heterogeneity. We hypothesized that antigens of the neurovascular extracellular matrix (nvECM) within GBM-disrupted blood-brain barrier (BBB) may localize and enhance efficacy of therapeutic agents.

METHODS: Yeast surface display biopanning and high throughput screening identified Variable Lymphocyte Receptors (VLR, i.e. jawless vertebrate lamprey antibodies) that preferentially accumulate at nvECM. Lead VLR candidates were tested for tumor targeting via combination with chemotherapeutic doxorubicin (DOX) liposomes and assessed for anti-GBM effects in vitro and against orthotopic mouse xenografts in vivo.

RESULTS: VLR clones were enriched for binding to mouse brain endothelial cell (bEnd.3 line) ECM with two rounds of biopanning, then screened for preferential binding to brain-derived ECM. Lead VLR clone P1C10 was chosen for further testing for nvECM specificity vs. fibroblast (3T3 line) ECM in a high throughput screen, high affinity (Kd=48±6.1 nM), and immunolabeling of normal mouse and human brain, and GBM samples. Clone P1C10 demonstrated tumor-specific targeting in orthotopic U87 GBM xenografts, with 50% more DOX fluorescence detected at GBM after intravenous injection of P1C10-DOX liposomes compared to control, non-specific VLR-DOX. Finally, administration of P1C10-DOX liposomes (15 mg/kg, i.p., 1/week) significantly improved survival of mice bearing U87 xenografts, compared to non-targeted VLR-DOX (Kaplan-Meier, p<0.01).

CONCLUSIONS: We report combining yeast surface display biopanning and screening to identify VLRs that preferentially accumulate at disrupted nvECM of GBM-disrupted BBB, and demonstrate GBM-targeting specificity in vitro and in vivo with significant survival benefit. These results support the nvECM immune-targeting strategy to improve anti-GBM therapeutic efficacy, potentially improving survival and quality-of-life in brain cancer patients.

Citation Format: Paul A. Clark, Benjamin J. Umlauf, Eric V. Shusta, John S. Kuo. Neurovascular-targeting antibodies discovered using yeast biopanning enhance drug delivery and improve survival for glioblastoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 1764.
Abstract 1768: An anti-TGF-β1/2 antibody that spares TGF-β3 retains full anti-tumor efficacy and generates an improved metabolic profile
Authors: Yang Yu-an , Vasu Srividya , Yang Howard , Lee Maxwell P. , Rane Sushil , Mirza Amer M. , Wakefield Lalage M.
Published: August 2018

TGF-β family members are overexpressed in many advanced cancers and correlate with metastasis and poor prognosis. Based on encouraging preclinical data, therapeutics that target the TGF-β pathway are now in early phase clinical trials in oncology. While the three isoforms of TGF-β have essentially identical activities in vitro, there is relatively little known about how they might differ in vivo. Using a panel of twelve mouse allograft models of metastatic breast cancer, we showed that while TGF-β1 protein was consistently up-regulated in mammary tumors compared with normal mammary gland, the opposite was true for TGF-β3. Furthermore, in human breast cancer high TGF-β3 mRNA or protein expression was associated with better outcome, particularly in estrogen-receptor positive breast cancers. Collectively the data suggest that TGF-β1 and TGF-β3 may have opposing effects on breast cancer progression. Using an antibody that selectively neutralizes only TGF-β1 and TGF-β2, we explored the effect of sparing TGF-β3 on therapeutic outcome in the 4T1 and TSAE1 models of metastatic breast cancer. While the TGFβ1,2 antibody and two pan-TGF-β antibodies had similar efficacy against the metastasis endpoint in these very aggressive models, transcriptomic analysis of primary tumors after two weeks of antibody therapy suggested that sparing TGF-β3 might have positive effects on the metabolic profile of treated animals. To address this issue directly, we showed that mice without tumors had a significantly improved glucose tolerance following treatment with anti-TGF-β1/2 antibodies for 2-3 weeks when compared with mice treated with pan-TGF-β antibodies. Addressing potential human relevance, we showed that high expression of transcripts that were selectively upregulated in the primary tumors when TGF-β3 was spared correlated with good outcome in human breast cancer. The data suggest that use of isoform-selective TGF-β antagonists may offer advantages over the use of pan-TGF-β blocking agents for the treatment of breast cancer.

Citation Format: Yu-an Yang, Srividya Vasu, Howard Yang, Maxwell P. Lee, Sushil Rane, Amer M. Mirza, Lalage M. Wakefield. An anti-TGF-β1/2 antibody that spares TGF-β3 retains full anti-tumor efficacy and generates an improved metabolic profile [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 1768.
Abstract 1792: Upregulation of INSR/IGF1Rby C-myc promotes TSCC tumorigenesis and metastasis through the NF-κB pathway
Authors: Wang Anxun , Sun Jingjing , Yu Mei , Lu Zhiyuan , Wang Wei
Published: August 2018

INSR/IGF1R has been detected to be involved in tumorigenesis and metastasis in various malignancies. The aim of our study was to compare the function role and mechanism of INSR/IGF1R in the progression of tongue squamous cell carcinoma (TSCC). We found that INSR had the same up-regulated expression pattern as IGF1R in TSCC tissues. Up-regulation of INSR/IGF1R was correlated each other and associated with lymph node metastasis and poor prognosis. Functional studies established that INSR/IGF1R knockdown dramatically impeded TSCC in vitro cell growth, migration, invasion and in vivo tumorigenesis and tumor metastasis, whereas ectopic overexpression of INSR/IGF1R enhanced these parameters. INSR/IGF1R promoted TSCC tumorigenesis and metastasis by positively modulating the NF-κB pathway. Furthermore, the up-regulation of INSR and IGF1R in TSCC resulted directly from the binding of C-myc to their promoters. Collectively, our current data demonstrate that the INSR/IGF1R axis, directly targeted by C-myc, plays an important role in the development and progression of TSCC, through NF-κB pathway, and that INSR and IGF1R are potential prognostic factors for TSCC.

Citation Format: Anxun Wang, Jingjing Sun, Mei Yu, Zhiyuan Lu, Wei Wang. Upregulation of INSR/IGF1Rby C-myc promotes TSCC tumorigenesis and metastasis through the NF-κB pathway [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 1792.
Abstract 1793: Gastrin-releasing peptide causes transactivation of the EGFR and HER2 in non-small cell lung cancer cells
Authors: Moody Terry W. , Alvarez Irene Ramos , Jensen Robert T.
Published: August 2018

Gastrin releasing peptide (GRP) is a 27 amino acid peptide which is present in many lung cancer cell lines (Moody et al., Science 1981; 214: 1246). High expression of the GRP receptor (R) is associated with advanced non-small cell lung cancer (NSCLC) (Mattei et al., Arch Pathol Lab Med 2014; 138: 98). GRP stimulates but the GRPR antagonist PD176252 inhibits the proliferation of NSCLC cells (Moody et al., Eur J Pharmacol 2003; 474: 21). Here the effects of GRP on the transactivation of the EGFR and HER2 were investigated in NSCLC cells. Six of 8 NSCLC tested had GRP-R mRNA whereas all the NSCLC cells had EGFR and HER2 mRNA. Addition of GRP to NCI-H1299 cells elevated cytosolic Ca2+, increased tyrosine phosphorylation of the ERK, EGFR and HER2 and increased colony number. The effects of GRP were blocked by PD176252. The transactivation of the EGFR and HER2 was inhibited by gefitinib (EGFR tyrosine kinase inhibitor (TKI)), lapatinib (EGFR and HER2 TKI), GM6001 (matrix metalloprotease inhibitor), PP2 (Src inhibitor), N-acetylcysteine (anti-oxidant) and transforming growth factor TGF) α antibody. By ELISA, GRP increased secretion of TGFα from lung cancer cells. PD176252, gefitinib, lapatinib and trastuzumab inhibited NSCLC growth. Activation of the GRPR in NSCLC cells may facilitate the formation of EGFR homodimers and EGFR/HER2 heterodimers.

Citation Format: Terry W. Moody, Irene Ramos Alvarez, Robert T. Jensen. Gastrin-releasing peptide causes transactivation of the EGFR and HER2 in non-small cell lung cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 1793.
Abstract 1794: The FES-related tyrosine kinase associates with and activates the insulin-like growth factor 1 receptor at sites of cell adhesion
Authors: Stanicka Joanna , Rieger Leonie , Cox Orla T. , O'Shea Sandra , Coleman Michael , O'Flanagan Ciara , Addario Barbara , McCabe Nuala , Kennedy Richard , O'Connor Rosemary
Published: August 2018

Insulin-like Growth Factor-1 signaling has a well-described function in facilitating tumourigenesis and promoting tumour growth. Attempts to suppress IGF signals at the level of the IGF-1 Receptor have been disappointing, with kinase inhibitors and blocking antibodies generally showing poor efficacy in clinical trials. To address the mechanisms for this lack of efficacy we sought to identify proteins that modulate the cytotoxic response to IGF-1R tyrosine kinase inhibition using a functional siRNA screen. We identified the non-receptor tyrosine FES-related (FER) kinase as a mediator of sensitivity to the IGF-1R tyrosine kinase inhibitor in MCF-7 cells. We found that FER and the IGF-1R co-locate and can be co-immunoprecipitated from different cell types. Ectopic expression of FER strongly enhanced IGF-1R expression and phosphorylation on the atuophosphorylation sites at tyrosines 950 and 1131. FER phosphorylated these sites in an IGF-1R kinase-independent manner and also enhanced IGF-1-mediated phosphorylation of SHC, and activation of either the AKT or MAPK signaling pathways in breast cancer cell lines. The IGF-1R, β1 Integrin, FER and its substrate cortactin were all observed to be co-located in cell adhesion complexes, the disruption of which reduced IGF-1R expression and activity. High FER expression correlates with phosphorylation of SHC in breast cancer cell lines and with a poor prognosis in patient cohorts. FER and SHC phosphorylation and IGF-1R expression could be suppressed with a known ALK inhibitor that shows high specificity for FER kinase. Overall, we conclude that FER-enhances IGF-1R expression, phosphorylation and signaling to promote cooperative growth and adhesion signaling that may facilitate cancer progression and resistance to IGF-1R inhibition.

Citation Format: Joanna Stanicka, Leonie Rieger, Orla T. Cox, Sandra O'Shea, Michael Coleman, Ciara O'Flanagan, Barbara Addario, Nuala McCabe, Richard Kennedy, Rosemary O'Connor. The FES-related tyrosine kinase associates with and activates the insulin-like growth factor 1 receptor at sites of cell adhesion [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 1794.
Abstract 1803: Dynamic pro-survival signaling mediates resistance to androgen receptor targeted therapy in AR-v7 splice variant expressing prostate cancer models
Authors: Pilling Amanda , Hwang Clara
Published: August 2018

Patient survival rates for metastatic prostate cancer are limited by therapeutic failure and disease progression. Treatment of castrate resistant prostate cancer (CRPC) remains a clinical challenge as current treatment options offer modest benefit and are not curative. Second generation androgen axis inhibitors such as enzalutamide and abiraterone acetate provide initial clinical benefit for patients. However, responses are not durable and disease progression is inevitable, resulting in limited patient survival. Several mechanisms of resistance have been identified that relate to persistent AR signaling including AR splice variants (ARVs) which encode an AR protein lacking the ligand binding domain (LBD). Since we have demonstrated that enzalutamide induces an apoptotic response in sensitive prostate tumor cells, we hypothesized that anti-apoptotic signaling is a critical mechanism of resistance to AR-targeted therapy in resistant tumor cell populations. Using 22Rv1 cells, a cell line model that expresses high levels of AR-v7, and cell lines that express low or no ARVs, we demonstrate differential activation of intrinsic/Bcl2-mediated apoptosis signaling in response to enzalutamide. Specifically, in 22Rv1 cells we demonstrate robust induction of anti-apoptotic signaling including increased Bcl-2 and Mcl-1 expression and inactivation of the apoptosis sensitizer Bad in response to enzalutamide, where this signaling is opposed in enzalutamide-sensitive cells. Analysis of potential upstream regulators revealed phosphorylation and activation of Akt through PI3K signaling in the ARV-expressing 22Rv1 cells in response to AR antagonism. Pharmacological inhibition of PI3K/Akt signaling in combination with enzalutamide prevented upregulation of Mcl-1 and inactivation of Bad, thus lowering the apoptotic threshold and sensitizing 22Rv1 cells to enzalutamide. In conclusion, this data demonstrates active engagement of pro-survival kinase signaling that mediates an increased apoptotic threshold in response to AR-directed therapy. Therefore, resistance to AR-directed therapy in ARV-expressing tumors may extend beyond the recognized mechanisms of treatment failure (i.e. lack of LBD for drug binding, constitutive AR transcriptional activity) and involve dynamic anti-apoptosis signaling. We demonstrate that strategies that lower the apoptotic threshold can increase sensitivity to AR antagonist in ARV-expressing cells and represents a novel therapeutic approach with potential to manage or overcome therapy resistance in this lethal form of prostate cancer.

Citation Format: Amanda Pilling, Clara Hwang. Dynamic pro-survival signaling mediates resistance to androgen receptor targeted therapy in AR-v7 splice variant expressing prostate cancer models [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 1803.
Abstract 1816: Mechanism of resistance to single treatment with MET inhibitor in EGFR-mutant lung cancer cell secondarily acquiring c-MET amplification
Authors: Lee Youngjoo , Choi Yu-Ra
Published: August 2018

Amplification in c-MET is the second most common mechanism of resistance to EGFR tyrosine kinase inhibitors (TKI) in lung cancer harboring activated EGFR mutations. An acquired resistance mechanism to single treatment with MET kinase inhibitor remains unknown. In this study, we modeled acquired resistance to experimental type I MET kinase inhibitor PHA66572 in MET-amplified HCC827 lung cancer cell line, which was established under chronic exposure to gefitinib in our lab. We found that reactivation of the EGFR pathway emerges as a resistance mechanism in MET secondarily amplified EGFR-mutant lung cancer cells after prolonged exposure to PHA66572. Any gene alteration influencing sensitivity to the drugs was not observed. Long treatment with only MET inhibitor resulted in partial resensitization to EGFR-TKI in these resistant lung cancer cells. Thus, the combination of gefitinib and PHA66572 could completely suppress the cell growth. Our findings support an intimate relationship between the EGFR and MET signaling pathways in HCC827 lung cancer cell line.

Citation Format: Youngjoo Lee, Yu-Ra Choi. Mechanism of resistance to single treatment with MET inhibitor in EGFR-mutant lung cancer cell secondarily acquiring c-MET amplification [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 1816.
Abstract 1820: Overcoming drug resistance in NSCLC with SRC inhibitor
Authors: Mukherjee Soumavo , Suresh Dhananjay , Zambre Ajit P. , Upendran Anandhi , Kannan Raghuraman
Published: August 2018

Lung cancer accounts for about 27 percent of all cancer deaths in the United States. Approximately 85 percent of lung cancers are non-small cell type (NSCLC) and, when treated with both chemotherapy and targeted therapies, have a five-year overall survival rate of approximately 16 percent. These statistics clearly emphasize the need for developing treatment methodologies more effective than the current standard of care. Here, we evaluated the efficacy of combined inhibition of SRC and AXL in NSCLC.Dasatinib, a BCR/abl and src family tyrosine kinase inhibitor (TKI) is a drug that has a potential to be used against both EGFR and KRAS mutated lung cancer patients, alone (phase II clinical trial) and in combination with cetuximab (in phase III clinical trial), osimertinib and erlotinib (both in phase II clinical trials) by exploiting its SRC inhibition capabilities. However, NSCLC patients treated with dasatinib often develop resistance and is the major reason for the low median survival in stage IV patients. Recently, AXL pathway has been shown to be upregulated in Dasatinib resistant cells causing activation of EMT, AKT and survival pathways. It has been suggested that auto-phosphorylation of DDR2 and subsequent activation of SHP2/RAS/AKT pathway as a result of AXL upregulation is one of the major reasons for failure to induce apoptosis in cells during dasatinib resistance. Therefore, we examined whether inhibition of AXL resensitized TKI resistant NSCLC to dasatinib. Our results show that AXL knockdown can resensitize cells to dasatinib. IC50 values decreased significantly following AXL inhibition. We have also demonstrated that nanoparticle-mediated AXL knockdown also produces similar resensitization. The details of the study will be presented.

Citation Format: Soumavo Mukherjee, Dhananjay Suresh, Ajit P. Zambre, Anandhi Upendran, Raghuraman Kannan. Overcoming drug resistance in NSCLC with SRC inhibitor [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 1820.
Abstract 1831: PKCδ as a novel target for HER2-positive, trastuzumab resistant breast cancer
Authors: Wyatt Debra L. , Zlobin Andrei , Ma Emily , Denning Mitchell F. , Osipo Clodia
Published: August 2018

Breast cancer is the most common cancer diagnosis and second leading cause of cancer related deaths among women in the United States. This poor prognosis is in part due to the high rates of resistance. In particular, resistance to anti-HER2-based therapy remains a clinical challenge for women with breast cancer suggesting that better treatment strategies are needed. Results demonstrate that resistance to trastuzumab correlates with lower PKC activity compared to trastuzumab sensitive breast cancer cells, suggesting that downregulation of PKC activity may contribute to trastuzumab resistance. The exact mechanism by which PKCs contribute to trastuzumab resistance is not well understood. Here, we hypothesized that activation of PKCs could prevent trastuzumab resistance and thus inhibit the survival and recurrence of HER2+ breast cancer. Our results show that in two distinct trastuzumab-resistant cell lines (HCC1954 and BT474), activation of PKC by the phorbol ester TPA inhibits both proliferation of bulk cells and survival of cancer stem cells (CSC) as assessed by mammosphere formation. Further, treatment using a pharmacological PKC inhibitor (GF109203X) almost completely rescued the anti-proliferative and anti-CSC survival effects of TPA in two distinct trastuzumab-resistant cell lines. Measurement of PKC isoforms at the transcript and protein levels showed that PKCδ was overexpressed in the resistant cell line compared to the sensitive cell line. PKCδ depletion using a siRNA prevented the anti-proliferative and anti-CSC survival effects of TPA, suggesting that PKCδ was the target of TPA activation in trastuzumab resistant cells. TPA-mediated activation of PKCδ was found to cause G2/M cell cycle arrest, almost complete inhibition of AKT phosphorylation at serine 473, and decreased expression of the CSC marker, ALDH1A1. These results suggest that phorbol ester-mediated activation of PKCδ could be a novel therapeutic strategy for HER2+ breast cancer that is resistant to trastuzumab-based therapy.

Citation Format: Debra L. Wyatt, Andrei Zlobin, Emily Ma, Mitchell F. Denning, Clodia Osipo. PKCδ as a novel target for HER2-positive, trastuzumab resistant breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 1831.
Abstract 1837: Overcoming trastuzumab resistance in HER2-overexpressing breast cancer by utilizing PHB2, a tumor suppressor of multiple resistance pathways
Authors: Yoshimaru Tetsuro , Matsushita Yosuke , Sasa Mitsunori , Miyoshi Yasuo , Katagiri Toyomasa
Published: August 2018

Overexpression of the human epidermal growth factor receptor 2 (HER2) is associated with aggressive tumor behavior and poor prognosis in breast cancer. Although anti-HER2 monoclonal antibody, trastuzumab shows considerable efficacy and extends the overall survival of patients with HER2 overexpressing breast cancer, about half of individuals with HER2-overexpressing breast cancer do not respond to trastuzumab-based therapies due to multiple resistance mechanisms. Therefore, acquired and de novo resistance to trastuzumab remains an important issue in the clinical treatment of HER2-overexpressing breast cancer. Our previous studies demonstrated that Brefeldin A-Inhibited Guanine nucleotide-exchange protein 3 (BIG3), which is exclusively overexpressed in the majority of breast cancers, functions as an A-kinase anchoring protein that binds protein kinase A (PKA) and protein phosphatase 1 (PP1Cα), thereby inactivating prohibitin2 (PHB2) suppressive activity through its dephosphorylation on Ser39. We further developed the stapled dominant-negative peptide (stERAP; stapled ERAP), which is designed to specifically inhibit the BIG3-PHB2 interaction and improve duration of their anti-tumor effects. Here we newly report that stERAP has significant suppressive effects on the HER2 signaling network by activating the tumor suppressive ability of PHB2. Intrinsic PHB2 released from BIG3 by stERAP was rapidly serine- and threonine-phosphorylated via PKCα and/or TTK, which are essential for its tumor suppressive activity, and effectively disrupted the HER2-HER3 interaction associated with acquired resistance to trastuzumab, resulting in significant reduction of proliferation of HER2-overexpressing breast cancer cells (IC50 = 54 nM in SK-BR-3 cells). We also confirm that stERAP inhibited HER2 phosphorylation on Thr488, HER2-HER3 interaction, and NF-κB pathway, which are associated with trastuzumab-resistance, respectively, resulting in significant suppression of growth of trastuzumab-resistant breast cancer cells. More importantly, stERAP treatment led to the enhancement of trastuzumab-sensitivity, resulting in a synergistic growth suppression of HER2-overexpressing and trastuzumab-resistant breast cancer cells, respectively. Our findings strongly suggest that stERAP is a novel promising anti-cancer drug to suppress the growth of trastuzumab-resistant breast cancer in clinical use.

Citation Format: Tetsuro Yoshimaru, Yosuke Matsushita, Mitsunori Sasa, Yasuo Miyoshi, Toyomasa Katagiri. Overcoming trastuzumab resistance in HER2-overexpressing breast cancer by utilizing PHB2, a tumor suppressor of multiple resistance pathways [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 1837.
Abstract 1844: Centriole amplification sensitizes cells to paclitaxel
Authors: Lasek Amber L. , Britigan Eric M. , Weaver Beth A.
Published: August 2018

Paclitaxel (Taxol) is a widely utilized treatment for primary and metastatic breast cancer. However, only about 50% of patients respond and no predictive biomarker for paclitaxel efficacy is currently available. Identification of a clinically validated predictive biomarker would substantially improve patient outcomes. Aneuploidy, an aberrant chromosome number, was recognized in the late 1800s as a hallmark of tumor cells. This led to the hypothesis that aneuploidy drives tumorigenesis. However, experiments in animal models have shown that the effect of aneuploidy on tumors depends on the rate of ongoing chromosome missegregation, also known as chromosomal instability (CIN). Low rates of CIN are weakly tumor promoting, while high rates of CIN lead to cell death and tumor suppression due to loss of one or more essential chromosomes. Combining two independent insults that each cause low CIN results in high CIN, cell death, and tumor suppression. We have recently shown that, in primary breast cancer patients, paclitaxel does not reach sufficiently high concentrations to cause mitotic arrest, as it does at typically used concentrations in cell culture. Instead, low clinically relevant doses of paclitaxel cause CIN due to multipolar spindles. We hypothesize that a preexisting low rate of chromosomal instability (CIN), which occurs in about 50% of breast tumors, sensitizes cells to paclitaxel treatment, since paclitaxel increases their rate of CIN over a maximally tolerated threshold. Centrosome amplification is common in breast cancer and can cause CIN through induction of multipolar spindles. To test whether CIN induced by centrosome amplification sensitizes cells to low, clinically relevant doses of paclitaxel, we inducibly overexpressed Polo-like kinase 4 (Plk4), the master regulator of centriole duplication, to generate supernumerary centrioles. Plk4 overexpression induced centriole amplification and increased the incidence of multipolar divisions, even in subclinical levels of paclitaxel. Consistent with our hypothesis, CIN induced by supernumerary centrosomes potentiates the decrease in cell viability caused by paclitaxel treatment. Decreased cell viability is accompanied by an increase in mitotic errors, CIN, and cell death and a reduction in the percentage of cycling cells. This data suggests that the subset of patients whose tumors exhibit centrosome amplification prior to treatment may be more likely to benefit from paclitaxel therapy.

Citation Format: Amber L. Lasek, Eric M. Britigan, Beth A. Weaver. Centriole amplification sensitizes cells to paclitaxel [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 1844.
Abstract 1873: Preclinical activity of tipifarnib in cutaneous T-cell lymphoma
Authors: Kohnken Rebecca , McNeil Betina , Wen Jing , McConnell Kathleen , Burrows Francis , Porcu Pierluigi , Mishra Anjali
Published: August 2018

Cutaneous T-cell lymphoma (CTCL) is a rare form of non-Hodgkin lymphoma characterized by malignant infiltration of skin-homing CD4+ T-cells, manifesting clinically as patches and plaques on the skin (Wong HK, et al. Br J Haematol 2011). The disease will often progress from an indolent skin-limited form, Mycosis Fungoides (MF), to an aggressive leukemic variant, Sezary Syndrome (SS) (Kohnken R, et al. Curr Hematol Malig Rep 2016). As there are few effective therapies available for advanced-stage CTCL, we sought to explore potential novel therapeutic modalities. Farnesyl transferase inhibitors (FTIs) are a relatively new class of anticancer drugs, the exact mechanism of which is unknown. Tipifarnib is one such FTI, which has demonstrated clinical activity as a single agent in patients with relapsed and refractory lymphomas (Witzig, TE, et al. Blood 2011). We utilized CTCL patient-derived cell lines to evaluate the potential efficacy of tipifarnib in vitro. EC50 doses ranged from 7.5nM for HuT78 to 50nM for SeAx. Importantly, there was no cytotoxic effect on normal donor CD4+ T-cells in vitro. Based on these promising findings, we evaluated tipifarnib in vivo using a recently described interleukin-15 (IL-15) transgenic mouse model of CTCL (Mishra A, et al. Can Discov 2016). Following two weeks of dosing in 5-week old mice, we found a significant decrease in gross lesion severity in tipifarnib-treated mice (0.5±1.22 out of a possible score of 5) compared to vehicle-treated mice (3.33±0.57, p=0.0076). Histologically, IL-15 transgenic mice develop characteristic malignant CD4+ T-cell infiltrates in the dermis and epidermis. Tipifarnib-treated mice, however, have minimal lesions in the skin. These dramatic changes are reflected in a significantly decreased histologic severity score in tipifarnib-treated mice (3.8±0.75 out of a possible score of 7 compared to vehicle-treated mice (7±0, p=0.0002). These findings demonstrate that tipifarnib is active in patient-derived cell lines and the mouse model of cutaneous T-cell lymphoma. Further studies to elucidate the mechanism of antitumor activity of farnesyl transferase inhibition in this cell type are in progress.

Citation Format: Rebecca Kohnken, Betina McNeil, Jing Wen, Kathleen McConnell, Francis Burrows, Pierluigi Porcu, Anjali Mishra. Preclinical activity of tipifarnib in cutaneous T-cell lymphoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 1873.
Abstract 1895: Landmark development of PI3K delta specific inhibitors for hematologic cancer therapeutics by data-driven drug design
Authors: Hong Suji , Kim Jong Woo , Lee Chi Woo
Published: August 2018

PI3K δ is hyper activated primarily in B cell malignancy and plays a central role in the malignant cell retention in proliferation, survival and homing at the lymphoid tissue and bone marrow in a variety of signaling pathways. Our BW compounds(BW-101, BW-108) are highly potent and selective PI3K δ inhibitors with marked selectivity over the other PI3K isoforms(α, β, γ). BW compounds are designed for the purpose of advancing the PI3K δ inhibition activity and overcoming the toxicities in which are hepatotoxicity and immunotoxicity due to small ratio of PI3K γ/PI3K δ. BW compounds are proven to be best-in-class in PI3K δ inhibition activity and to possess a bigger ratio of PI3K γ/PI3K δ related to the immunotoxicity than that of Idelalisib As small molecules, they inhibit PI3Kδ in the way of competing with ATP strongly at PI3Kδ binding site that issues in apoptosis of malignant B and T cell through blocking AKT down pathway. BW compounds have shown the good PK profiles in rat so that their in vivo efficacies were superior to those of Idelalisib in xenograft studies. Such a result demonstrated the therapeutic potential of these compounds in acute leukemia mediated via the PI3Kδpathway. In the side of toxicity, BW compounds also are showing desirable properties.

Citation Format: Suji Hong, Jong Woo Kim, Chi Woo Lee. Landmark development of PI3K delta specific inhibitors for hematologic cancer therapeutics by data-driven drug design [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 1895.