bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 1981: Tissue-engineered bone for longitudinal intravital microscopy of solid tumor growth and therapy response
Authors: Dondossola Eleonora , Alexander Stephanie , Holzapfel Boris , Logothetis Christopher J. , Hutmacher Dietmar W. , Friedl Peter
Published: July 2017

Bone metastases are the initial site of progression and account for many of the complications experienced by men with metastatic prostate cancer (PCa), including therapy resistance. Besides cell intrinsic mechanisms, the interaction between PCa cells and the bone microenvironment critically contributes to lesion expansion and drug sensitivity. We here developed a mouse model amenable to intravital multiphoton microscopy (iMPM) to longitudinally study PCa-stromal cell interactions and therapy response in a partially humanized neobone, established in the dermis of the mouse. Tissue engineered bone constructs, TEBCs, were generated by functionalizing polymeric polycaprolactone scaffolds with human mesenchymal stem cells (hMSCs) differentiated to osteoblasts followed by cell-derived calcification of the inter-scaffold space. 30 days after implantation of functionalized scaffolds under the skin of the mouse, bone and bone marrow maturation resulted in a 30mm3 cavity surrounded by optically transparent cortical bone of 50-60 μm thickness, as monitored by microCT and iMPM. Intra-bone tumor growth and osteolysis dynamics caused by human fluorescent PCa cells (PC3) were three-dimensionally reconstructed by multi-parameter detection through a body window, including collagen and bone matrix (SHG), calcified bone (fluorescent bisphosphonates), osteoclasts (cathepsin K), bone surface (THG), blood vessels and stromal phagocytes (fluorescent dextran), and PC3 cells (nuclear H2B/eGFP, cytoplasmatic DsRed2). As a proof of concept, the efficacy to halt bone remodeling during bisphosphonate therapy was detected, revealing the composition and kinetics of the bone-tumor interface. Combining engineered neobone with an optical window is suited to detail the 3D organization and dynamics of cancer lesions in bone and provides mechanistic insight and efficacy predictions for therapy response. Thus, this strategy will be implied to dissect the therapeutic effect of radium 223, a radioisotope with bone seeking properties, and the first agent that improves the duration and quality of life of advanced metastatic PCa patients. By using this model we will test the hypothesis that 223Ra alters stromal niches, structurally and molecularly, in a manner that accounts for the clinical observations in established macroscopic lesions.

Citation Format: Eleonora Dondossola, Stephanie Alexander, Boris Holzapfel, Christopher J. Logothetis, Dietmar W. Hutmacher, Peter Friedl. Tissue-engineered bone for longitudinal intravital microscopy of solid tumor growth and therapy response [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 1981. doi:10.1158/1538-7445.AM2017-1981
Abstract 1985: Tbk1 loss in pancreatic cancer leads to changes in epithelial plasticity
Authors: Burton Victoria Haley , Brekken Rolf A. , Gross Melissa , Bremauntz Alberto
Published: July 2017

Effective therapies are needed to enhance the long-term survival of patients with pancreatic ductal adenocarcinoma (PDA), which is the fourth leading cause of cancer-related deaths in the United States and eighth worldwide. Initial stages of PDA are commonly characterized by an activating mutation in K-RAS, yet direct inhibition of K-RAS through pharmacological means remains a challenge. Higher levels of TANK Binding Kinase 1 (TBK1) mRNA, a critical downstream effector of mutant active K-RAS in lung cancer, are associated with poorer overall survival in a cohort of human PDA patients. We hypothesize that TBK1 is also an effective mediator of K-RAS driven pancreatic cancer.

Here we report that TBK1 is expressed and more active in human PDA cell lines relative to immortalized pancreatic epithelial lines (HPNE) and fibroblasts. We found that human PDA cell lines are sensitive to a small molecule inhibitor of TBK1 in the low micromolar range. Further mice engineered to express a mutant kinase dead form of TBK1 (Tbk1Δ/Δ) are viable and fertile yet display smaller tumors at early time points in a genetically engineered mouse model of PDA. Interestingly, tumors from Tbk1Δ/Δ: PDA mice are more epithelial in gene expression and show significantly less collagen deposition compared to Tbk1+/+: PDA tumors. Additionally, cell lines isolated from Tbk1Δ/Δ: PDA tumors are more epithelial in morphology and less migratory and invasive relative to Tbk1+/+: PDA cell lines. Current work is focused on delineating the functional contribution of TBK1 to tumor cell motility in vivo as well as mechanistic understanding of the epithelial phenotype in Tbk1Δ/Δ: PDA tumors. These results will further our understanding of Ras signaling in pancreatic cancer and are critical for exploring a new avenue of targeted therapy.

Citation Format: Victoria Haley Burton, Rolf A. Brekken, Melissa Gross, Alberto Bremauntz. Tbk1 loss in pancreatic cancer leads to changes in epithelial plasticity [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 1985. doi:10.1158/1538-7445.AM2017-1985
Abstract 1988: Exosome-mediated ovarian cancer tumorigenesis mediated by miR1246/Rb/Cav1 axis
Authors: Kanlikilicer Pinar , Bayraktar Recep , Rashed Mohammed , Aslan Burcu , Calin George A. , Sood Anil K. , Lopez-Berestein Gabriel
Published: July 2017

Exosomes are secreted from many cell types and play an important role in the tumor microenvironment. The most impressive breakthrough in exosomes research was that they contain the genetic material of the host cell. However, whether cancer cells use their exosomes to transfer their oncogenic material to recipient cells, or to get rid of their tumor suppressor material is not well understood. We previously identified that miR-1246 was hundreds of folds higher expressed in six different ovarian cancer exosomes compared to their originating cells. Here, we showed that miR-1246 co-localized in the exosomes in ovarian cancer cells. miR-1246 act as an oncogenic miRNA and the levels were elevated in ovarian cancer patients compared to health donors. We also demonstrated that miR-1246 inhibitor treatment in combination with paclitaxel was significantly inhibited tumor burden in SKOV3-ip1 orthotopic ovarian cancer model. Our results suggest that miR-1246 inhibited RB tumor suppressor protein and regulate Cav-1 and platelet-derived growth factor receptor beta precursor signaling in ovarian cancer. In addition Inhibiting miR-1246 led a significant decrease in exosome release. Together, our findings provide strong evidence that oncogenic miR-1246 can be targeted as a potential novel therapeutic approach in the treatment of ovarian cancer.

.

Note: This abstract was not presented at the meeting.

Citation Format: Pinar Kanlikilicer, Recep Bayraktar, Mohammed Rashed, Burcu Aslan, George A. Calin, Anil K. Sood, Gabriel Lopez-Berestein. Exosome-mediated ovarian cancer tumorigenesis mediated by miR1246/Rb/Cav1 axis [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 1988. doi:10.1158/1538-7445.AM2017-1988
Abstract 1990: Single cell co-expression profiles of immunotherapy targets in the tumor microenvironment of NSCLC samples
Authors: Kim Jeffrey , Su Nan , Ma Xiao-Jun , Park Emily
Published: July 2017

Cancer immunotherapies have made great strides in recent years, yet identifying key molecules in the tumor microenvironment is necessary to develop improved approaches to achieve more durable responses in a greater number of patients. Obstacles such as adaptive resistance to individual checkpoint marker blockade, such as PD1 and CTLA4, have led researchers down the path of pursuing multiple immune targets that may be upregulated on the same lymphocyte as a consequence of mono-antibody therapies. While several clinical trials taking a combinatorial approach are currently in progress, including targeting multiple checkpoint markers, it is clear that these new strategies may rely on the pre-existing immune system, regardless of being treatment naïve or previously treated. The challenge now is to identify the relevant biomarkers and to stratify patients to provide the most appropriate treatment. As a proof of concept, here we evaluate single cell co-expression profiles of key therapeutic targets in archived tissues of non-small cell lung cancer (NSCLC) samples using the RNAscope® Duplex Assay, an advanced in situ hybridization platform that allows for the visualization of single cell gene expression of mRNA targets directly in tissue.

In our investigation of 60 archived formalin-fixed paraffin embedded NSCLC tissues, co-expression profiles of PD1 or PD-L1 coupled with another therapeutic target (IDO1, LAG3, 4-1BB, GITR, and TIM3) were assessed, bringing to light substantial variations in the tumor microenvironment between tissue samples. These marked differences of co-expressed targets on tumor infiltrating lymphocytes were scrutinized through quantitative image analysis to further reveal both the diversity and degree of individuality between tissue samples. Quantitatively measuring the expression of multiple targets in single cells within intact tissues exposed the distinct milieu of targetable therapeutic molecules, leading to the potential identification of responsive tumors which could help guide in stratifying patients for different combinatorial approaches.

Citation Format: Jeffrey Kim, Nan Su, Xiao-Jun Ma, Emily Park. Single cell co-expression profiles of immunotherapy targets in the tumor microenvironment of NSCLC samples [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 1990. doi:10.1158/1538-7445.AM2017-1990
Abstract 2004: Epigenetic targeting of CD276 expression in medullolbastoma
Authors: Guda Maheedhara R. , Castellanos Jose R. , Labak Collin M. , Sanam Ramadevi , Daniels David J. , Martin Sarah E. , Lin Julian J. , Tsung Andrew J. , Velpula Kiran K. , Asuthkar Swapna
Published: July 2017

Medulloblastoma (MB) is the most common malignant brain tumor in children and accounts for 20% of pediatric CNS tumors. Following surgery and treatment with chemotherapy and radiation, MBs recur in a significant proportion of patients. Moreover, survivors experience comorbidities related to the tumor and/or its treatment. New insights into MB tumor pathogenesis are needed for improving the survivorship and outcome of MB. Epigenetic silencing, including histone modification and DNA methylation, is an important tumorigenic mechanism in MB. However, its role in cancer immunopathology is poorly understood. Using datamining and immunohistochemistry analysis, we show that B7-H3 (CD276), an important immune checkpoint member of the B7 and CD28 families, is highly upregulated in all four molecular subtypes of MB compared to normal tissue. Based on the clinical success of inhibitory immune checkpoint blockades (CTLA-4, PD-1, and PD-L1), CD276 appears to be a promising therapeutic target for cancer immunotherapy. Moreover, we observed that increased expression of CD276 correlates significantly with the expression of Enhancer of Zeste Homologue 2 (EZH2), a histone H3-methylating (H3K27me3) catalytic subunit in the human MB specimens. We hypothesize that combined targeting of CD276 and EZH2 may have greater impact on tumor progression and immune cell response in MB. Simultaneously, we performed LC/MS analysis to identify novel interaction partners of CD276 in MB tumor. These findings taken together suggest that CD276 is strongly associated with several epigenetic markers, indicating a strong relationship between cancer immune evasion and epigenetic mechanisms.

Citation Format: Maheedhara R. Guda, Jose R. Castellanos, Collin M. Labak, Ramadevi Sanam, David J. Daniels, Sarah E. Martin, Julian J. Lin, Andrew J. Tsung, Kiran K. Velpula, Swapna Asuthkar. Epigenetic targeting of CD276 expression in medullolbastoma [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 2004. doi:10.1158/1538-7445.AM2017-2004
Abstract 2014: Genitourinary cancer-derived cells produce microenvironment proteinases that regulate proteinase activated receptors (PARs) to drive oncogenic signaling
Authors: Gibson Stacy G. , Mihara Koichiro , Zijlstra Andries , Hyndman Matthew E. , Hollenberg Morley D.
Published: July 2017

Background:

Thrombin-triggered activation of proteinase-activated receptor-1 (PAR1) is recognized as a key stimulus for driving epithelial malignancies (IUBMB life.63:397, 2011; PMID:21557443). However, the enzymes for regulating PAR1 in the tumour microenvironment are not known.

Hypothesis:

We hypothesize that prostate (PC) and urinary bladder cancer (UBC) cells can regulate microenvironment signaling to drive cancer progression via the secretion of proteinases that cleave/regulate proteinase-activated receptors (PARs).

Aims:

1.) Visualize the cleavage status of N- and C-terminally-dual-labelled PARs in receptor-transfected UBC- and PC-derived cells.

2.) Measure PAR cleavage by UBC and PC-secreted proteinases.

3.) Identify the UBC & PC-derived proteinases that cleave/regulate PAR function.

Methods:

The cleavage status of dual-labeled PARs (N-terminus-mCherry/C-terminus-YFP) expressed in PC & UBC cells was determined by confocal image analysis as already described (JBC 288:32979, 2013; PMID: 26957205). Intact receptors look 'yellow' and cleaved receptors look 'green'. The cleavage of PARs in UBC and PC cells was studied for dual-tagged-PAR-expressing UBC and PC cells exposed or not to cell-derived culture supernatants, enzyme agonists for PAR1 and 2 (thrombin and trypsin, respectively), and proteinase inhibitors (e.g. for MMPs and other enzymes). The impact of CRISPR-mediated elimination of MMPs from PC3 cells on PAR1 cleavage status was also monitored.

Results:

UBC- and PC-produced enzymes can cleave PAR1 as efficiently as thrombin, an established PAR1 agonist. None of the UBC cell lines produce proteinases that cleave PAR2. Inhibition of MMP activity partially prevents PAR1 cleavage by UBC cells and completely prevents PAR1 cleavage in PC3-PC cells.

Conclusions:

We conclude that UBC and PC cells secrete PAR-regulating proteinases that can directly regulate PAR1 in the tumour microenvironment so as to drive cancer progression.

Funding:

Alberta Innovates CRIO Grant, Prostate Cancer Canada Discovery Grant, Motorcycle Ride for Dad, Johnson & Johnson Alberta Health Partnership and CIHR

Note: This abstract was not presented at the meeting.

Citation Format: Stacy G. Gibson, Koichiro Mihara, Andries Zijlstra, Matthew E. Hyndman, Morley D. Hollenberg. Genitourinary cancer-derived cells produce microenvironment proteinases that regulate proteinase activated receptors (PARs) to drive oncogenic 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 2014. doi:10.1158/1538-7445.AM2017-2014
Abstract 2015: Mesenchymal stem cell correlates oral leukoplakia malignant transformation through regulate T cell response
Authors: Chen Yichen , He Bailin , Ma Da , Song Jingjing , Wang Xi , Cheng Bin , Wang Zhi
Published: July 2017

Introduction

Leukoplakia is one of the most common clinically presented oral potential malignant disorders (OPMD). Detailed understanding of leukoplakia-associated molecular or cellular changes would help us better undertand about the progress of leukoplakia malignant transformation. In this study, we examined the potential involvement of MSC in this very progress, and demonstrated lesion resident MSCs may favour leukoplakia malignant transformation through its strong immunoregulation on T cell.

Methods

Eighteen six-week-old female Sprague-Dawley rats (180-220g) were given 0.05g/L 4NQO in drinking water for 22 weeks for development of lesions. Lesions classfied by histological HE stainnig. MSCs were obtained from single cell suspesion of lesions, and cultured with splenocyte to study its immunoregulate ability.

Results

1. MSC-like cells are enriched in carcinogen induced leukoplakia and cancers. Representative results showing the lesions on tongue of rats. And relative proportion of MSC phenotype marker (CD29+, CD31-, CD45-, CD90+) in oral lesions (OMSC) were counted by flow cytometry.

2. Leukoplakia-derived MSC (L-OMSC), cancer-derived MSC (C-OMSC), and the normal mucosa-derived MSC (N-OMSC) share the similar stemness properties.

3. Cancer lesion have less infiltrating T cells (quantified by IHC and FCM of CD3 ). Cancer-derived MSCs suppress T cell proliferation, but not promote T cell apoptosis and inhibit T cell migration to the lesions.

4. Higher number of lesion derived MSCs associates with higher celluar proliferation in the lesions.

Summary

Our study demonstrated MSCs could migrate to pre-malignant leukoplakia lesions prior to tumor establishment. Further, MSCs play an important role in leukoplakia malignant transformation induced by chemicals, which via its strong immunomodulatory activities.

Citation Format: Yichen Chen, Bailin He, Da Ma, Jingjing Song, Xi Wang, Bin Cheng, Zhi Wang. Mesenchymal stem cell correlates oral leukoplakia malignant transformation through regulate T cell response [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2015. doi:10.1158/1538-7445.AM2017-2015
Abstract 2020: Synergistic induction of apoptosis of combined mesupron and auranofin treatment in human breast cancer cells
Authors: Lee Joo-Eun , Kwon Yeo-Jung , Oh Kyung-Soo , Chun Young-Jin
Published: July 2017

Urokinase-type plasminogen activator (uPA) system may play a crucial role in cancer cell invasion and metastasis. uPA has been validated as a predictive or prognostic biomarker protein and considered as a therapeutic target in human breast cancer. Mesupron is a uPA inhibitor blocking uPA enzymatic activity to reduce tumor cell invasion, migration and cell growth. Auranofin has been known as an antirheumatic drug and a thioredoxin reductase inhibitor and recently its anticancer activity in ovarian and breast cancers has also been identified. To study whether cotreatment with mesupron and auranofin shows a significant anticancer activity, the synergistic induction of apoptosis of mesupron with auranofin was determined. Auranofin or mesupron alone inhibited cancer cell growth in MCF-7 cells with IC50 of 0.25 μM or 25 μM, respectively. Flow cytometric analysis also showed an increased apoptosis. When cells were treated with mesupron (0.125 μM) in combination with auranofin (10 μM), we found a significant induction of apoptosis although the cytotoxic effects of mesupron or auranofin alone at those concentrations were not quite strong. Interestingly, combined mesupron and auranofin treatment significantly suppressed mitochondrial antiapoptotic proteins including Bcl-2 and Bcl-xL. We also found the increase of caspase-3 and PARP cleavages. The combination index (CI) also indicated the synergistic induction of apoptosis by auranofin and mesupron. Taken together, these data suggest that the use of mesupron and auranofin in combination can be valuable to achieve higher anticancer activity.

Note: This abstract was not presented at the meeting.

Citation Format: Joo-Eun Lee, Yeo-Jung Kwon, Kyung-Soo Oh, Young-Jin Chun. Synergistic induction of apoptosis of combined mesupron and auranofin treatment in human 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 2020. doi:10.1158/1538-7445.AM2017-2020
Abstract 2024: Reactivating apoptosis in BFL-1/A1 driven cancer with cysteine-reactive stapled peptide inhibitors
Authors: Guerra Rachel M. , Huhn Annissa J. , Harvey Edward P. , Bird Gregory H. , Walensky Loren D.
Published: July 2017

BFL-1/A1 is a BCL-2 family protein implicated in the progression and chemoresistance of melanoma, lymphoma, and other cancers, yet it remains undrugged. Anti-apoptotic BCL-2 family proteins block cell death by trapping the critical α-helical BH3 domains of pro-apoptotic members in a surface groove. Cancer cells hijack this survival mechanism by overexpressing a spectrum of anti-apoptotic members, mounting formidable apoptotic blockades that resist chemotherapeutic treatment. Drugging the BH3-binding pockets of anti-apoptotic proteins has become a highest-priority goal, fueled by the clinical success of venetoclax, a selective BCL-2 inhibitor, in reactivating apoptosis in BCL-2-dependent cancers. A natural juxtaposition of two unique cysteines at the binding interface of the NOXA BH3 helix and BFL-1/A1 pocket informed the development of stapled BH3 peptides bearing acrylamide warheads to irreversibly inhibit BFL-1/A1 by covalent targeting. Here, we describe the development and application of cysteine-reactive stapled peptides that, compared to their non-covalent analogs, trigger rapid mitochondrial cytochrome c release, caspase 3/7 activation, and apoptosis induction of BFL-1/A1 driven cancers such as melanoma. Mechanism of action studies demonstrated the exquisite BFL-1/A1 selectivity and mitochondrial localization of the in situ covalent reaction. Given the frequent proximity of native cysteines to regulatory binding surfaces, covalent stapled peptide inhibitors provide a new therapeutic strategy for targeting oncogenic protein interactions.

Citation Format: Rachel M. Guerra, Annissa J. Huhn, Edward P. Harvey, Gregory H. Bird, Loren D. Walensky. Reactivating apoptosis in BFL-1/A1 driven cancer with cysteine-reactive stapled peptide inhibitors [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 2024. doi:10.1158/1538-7445.AM2017-2024
Abstract 2034: LSD1 inhibition alone and in combination with chemotherapy in Ewing sarcoma cell lines
Authors: Welch Darcy , Kahen Elliot , Cubitt Christopher L. , Reed Damon R.
Published: July 2017

Background: Ewing Sarcoma (ES) is the second most common primary bone cancer affecting children and young adults. Despite advances in treatment that have led to survival rates of approximately 73% for localized disease, outcomes for patients with metastatic or recurrent ES remain poor. A distinguishing feature of ES is the presence of the EWS/FLI1 fusion in 85% of cases. The fusion has been shown to alter expression of a number of oncogenic genes. Mechanistic studies have demonstrated that the NuRD co-repressor complex interacts with EWS/FLI1. The associated protein LSD-1 contributes to the repressive function by histone modifications. While reversible LSD1 inhibitors demonstrate single agent activity, in preclinical models, a system to evaluate combinations may be needed for optimizing effect in clinical trials.

Methods: Here, we seek to confirm promising single drug activity and evaluate combination therapies using active chemotherapies currently utilized in ES care (4-HC, etoposide, SN-38, vincristine and doxorubicin) along with the LSD1 Inhibitors SP2509 and SP2577 and romidepsin, an HDAC inhibitor. We evaluated these combinations in high-throughput screening platforms and well-established cell line models for ES (A-673, TC-32, RD-ES, TC-71). Taking into consideration past lessons learned from in vitro experiments, we designed stringent screening conditions that assess the candidate compounds and combinations at clinically-relevant concentrations and exposure times that mimic the in vivo pharmacokinetics in an effort to maximize the translational potential of these results to the clinical setting. All combinations of agents were studied in two-drug combinations to evaluate for synergy in addition to efficacy.

Results: IC50 for SP2509 was found to be in the submicromolar range across cell lines with SP2577 being more potent. A-673 and TC-71 were 5-10 fold less sensitive than RD-ES and TC-32. Agents currently utilized in clinic were universally active at clinically achievable concentrations and exposure times. Combinations showed additivity frequently and demonstrated promising activity that can be used to inform further decision making once LSD1 inhibition toxicities are better known. These findings suggest potentially promising opportunities for developing combination clinical trials to maximize development of LSD1 inhibitors.

Citation Format: Darcy Welch, Elliot Kahen, Christopher L. Cubitt, Damon R. Reed. LSD1 inhibition alone and in combination with chemotherapy in Ewing sarcoma cell lines [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 2034. doi:10.1158/1538-7445.AM2017-2034
Abstract 2037: Oral nitroxoline in combination with intravesical bacille calmette-guerin (BCG) shows synergistic antitumor efficacy in mouse bladder cancer orthotopic xenograft
Authors: Li Qiang , Pan Kevin , Li Xiezhao , Xu Naijin , Huang Peng
Published: July 2017

Nitroxoline, an antibiotic used to treat urinary tract infection, had previously been identified as a MetAP2 inhibitor and found to show antitumor efficacy in mouse models of human breast cancer xenograft and bladder cancer orthotopic xenograft [1]. Our purpose in this study was to evaluate the feasibility of combining oral nitroxoline with intravesical BCG, the first-line therapy for intermediate- and high-risk non-muscle invasive bladder cancer (NMIBC), in mouse bladder cancer orthotopic xenograft. The luciferase-expressing murine bladder cancer cell line MBT-2-Luc cells was transurethrally implanted in the bladder of syngeneic female C3H/He mice. The animals were randomly divided into groups and treated with phosphate-buffered saline (PBS), oral nitroxoline, intravesical BCG alone, and a combination as described in methods. The IVIS spectrum images analyses of luciferin-stained tumor at 21 days after inoculation revealed that combining oral nitroxoline with intravesical BCG showed synergistically enhanced antitumor efficacy and prolonged long-term survival, implicating the potential of combining bladder cancer treatment using oral nitroxoline with intravesical BCG in the clinical setting. The mechanism behind this observation is currently under investigated.

Citation Format: Qiang Li, Kevin Pan, Xiezhao Li, Naijin Xu, Peng Huang. Oral nitroxoline in combination with intravesical bacille calmette-guerin (BCG) shows synergistic antitumor efficacy in mouse bladder cancer orthotopic xenograft [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 2037. doi:10.1158/1538-7445.AM2017-2037
Abstract 2038: Reactive oxygen species-mediated synergism of fenretinide and romidepsin in preclinical models of T-cell lymphoid malignancies
Authors: Makena Monish Ram , Koneru Balakrishna , Kang Min H. , Reynolds C. Patrick
Published: July 2017

Introduction: T-cell lymphoid malignancies (TCLMs) are in need of novel and more effective therapies. Romidepsin is a histone deacetylase (HDAC) inhibitor that achieved FDA registration as 2nd line therapy for peripheral and cutaneous T-cell lymphomas. The cytotoxic retinoid fenretinide achieved durable complete responses against T-cell lymphomas in early-phase clinical trials and T-cell lymphoma patients who failed prior romidepsin treatment responded to fenretinide. Fenretinide is currently being evaluated in a Phase IIa clinical trial for relapsed/refractory PTCL patients (NCT02495415). We investigated the potential for using these two agents in combination in TCLMs. Methods and Results: Using the DIMSCAN assay, we demonstrated cytotoxic synergy between romidepsin and fenretinide in fifteen TCLM cell lines at clinically-achievable concentrations that lacked cytotoxicity for non-malignant cells (fibroblasts and blood mononuclear cells). In vivo, romidepsin + fenretinide + ketoconazole (enhances fenretinide exposures by inhibiting fenretinide metabolism) showed greater activity in subcutaneous (COG-LL-317m and TX-LY-183x PDX) and disseminated (COG-LL-317m Luc expressing the luciferase gene) TCLM xenograft models than single agent romidepsin or fenretinide + ketoconazole. Fenretinide + romidepsin caused a reactive oxygen species (ROS, measured by DCFDA dye)-dependent increase in pro-apoptotic proteins (Bim, tBid, Bax and Bad), apoptosis (via TUNEL assay), and inhibition of HDAC enzymatic activity, which achieved a synergistic increase in histone acetylation. The synergistic cytotoxicity, apoptosis, and histone acetylation of fenretinide + romidepsin was abrogated by antioxidants (vitamins C or E). Romidepsin + fenretinide activated p38 and JNK via ROS, and shRNA knockdown of p38 and JNK1 significantly decreased the synergistic cytotoxicity and apoptosis. Romidepsin + fenretinide also showed synergistic cytotoxicity for B-lymphoid malignancy cell lines, but did not increase ROS, acetylation of histones, activation of p38 + JNK, or cytotoxicity in fibroblasts and blood mononuclear cells. Conclusion: Romidepsin + fenretinide achieved synergistic activity in preclinical models of TCLMs, but not in non-malignant cells, via a novel molecular mechanism. These data support conducting clinical trials of romidepsin + fenretinide in relapsed and refractory TCLMs.

Citation Format: Monish Ram Makena, Balakrishna Koneru, Min H. Kang, C. Patrick Reynolds. Reactive oxygen species-mediated synergism of fenretinide and romidepsin in preclinical models of T-cell lymphoid malignancies [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 2038. doi:10.1158/1538-7445.AM2017-2038
Abstract 2042: Nano-tetraiodothyroacetic acid (NDAT) potentiates gefitinib-induced antiproliferation in colorectal cancer cells by inhibiting EGFR sialylation and PI3K activation
Authors: Chin Yu-Tang , Lin Chi-Yu , Changou Chun A. , Whang-Peng Jacqueline , Davis Paul J. , Lin Hung-Yun
Published: July 2017

The resistance of gefitinib has been revealed to complicate cancer therapy. Tetraiodothyroacetic acid (tetrac) and its nanoparticulate derivative (NDAT, nano-tetrac) have been proved in vitro and in vivo xenograft demonstrating anti-proliferative and anti-angiogenetic activities. It also indicates that they potentiate anti-cancer agent-induced anti-proliferation in cancer cells. In this study, we investigated the effects of NDAT on gefitinib-induced anti-cancer activities in human colorectal cancer cells. Gefitinib inhibited cell proliferation at concentration 1 μM in K-ras wild type HT29 cell and NDAT enhanced the anti-proliferation-induced gefitinib significantly. Meanwhile, both inhibited proliferative and metastatic genes expression in HT29 cells. On the other hand, 10 μM gefitinib inhibited cell proliferation in K-ras mutant HCT116 cell which was further enhanced by NDAT. Different from results in HT-29 cells, only NDAT inhibited proliferative and metastatic genes expression significantly and enhanced the effect of gefitinib in HCT116 cells. ST6Gal-1 catalyzes sialylation of EGFR and induces gefitinib-resistant in colorectal cancers. In addition, NDAT did reduced not only ST6Gal-1 gene expression, but also its protein production. However, the inhibition of ST6Gal-1 expression may not be sufficient to induced anti-proliferation in colorectal cancer cells. PI3K inhibitor, LY294002, was able to potentiate the gefitinib-induced anti-proliferation in

HCT116 cells suggesting that constitutive activation of PI3K may play a key role on gefitinib-resistance in HCT116 cells. In summary, NDAT potentiated gefitinib-induced anti-proliferation via inhibiting the activity of ST6Gal-1 and PI3K activation in gefitinib-resistant colorectal cancer cells.

Citation Format: Yu-Tang Chin, Chi-Yu Lin, Chun A. Changou, Jacqueline Whang-Peng, Paul J. Davis, Hung-Yun Lin. Nano-tetraiodothyroacetic acid (NDAT) potentiates gefitinib-induced antiproliferation in colorectal cancer cells by inhibiting EGFR sialylation and PI3K activation [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 2042. doi:10.1158/1538-7445.AM2017-2042
Abstract 2043: Entinostat in combination with Cladribine synergistically induces apoptosis in multiple myeloma cells
Authors: Wang Bolun , Lyu Hui , Liu Bolin
Published: July 2017

Cladribine (2-CDA) is a well-known purine nucleoside analog against lymphoproliferative disorders. Entinostat, a selective class I histone deacetylase (HDAC) inhibitor, exerts anti-tumor activity in various cancers, including multiple myeloma (MM). We sought to determine whether cladribine and entinostat may exhibit synergistic anti-proliferative/anti-survival effects on MM cells. Here we showed that, in cell growth MTS assays, either cladribine or entinostat alone inhibited cell proliferation in a dose-dependent manner. The combinations of cladribine and entinostat significantly induced growth inhibition in MM cells tested. The combination index (CI) curves showed a synergistic effect between cladribine and entinostat. An apoptotic-ELISA and western blot analyses of caspase-3 and PARP revealed that entinostat in combination with cladribine exhibited a much more potent activity than either agent alone to promote the MM cells undergoing apoptosis in a dose and time-dependent manner. Collectively, our data suggest that combinations of entinostat and cladribine possess synergistic anti-proliferative/anti-survival activity in MM cells. Regimens consisting of entinostat and cladribine may represent novel therapeutic strategies against MM.

Citation Format: Bolun Wang, Hui Lyu, Bolin Liu. Entinostat in combination with Cladribine synergistically induces apoptosis in multiple myeloma 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 2043. doi:10.1158/1538-7445.AM2017-2043
Abstract 2045: Exploring the potential of cellular thermal shift assay (CETSA) to study drug resistance during cancer therapy
Authors: Sreekumar Lekshmy Kunjamma Usha , Lim Yan Ting , Veerappan Saranya , Nordlund Par
Published: July 2017

The aim of this project is to understand the various mechanisms contributing to drug resistance development in cancer therapy.

The efficacy of therapeutics is dependent on a drug binding to its target. We have developed a method that allows for the first time to directly evaluate drug binding to target proteins in cells and tissue samples the cellular thermal shift assay (CETSA) (Martinez Molina et al. Science, 341:84). CETSA is based on the biophysical principle of ligand-induced thermal stabilization of target proteins. By monitoring the drug occupancy in the target protein, CETSA can be used to study processes of drug transport and metabolism in cancer cells. We have used CETSA to study the acquired drug resistance of, antifolate and fluropyrimidine drugs in pairs of parental and resistant cell lines. CETSA shifts and isothermal dose response fingerprint (ITDRF) were used to study the relative drug target engagement in these cells. Quantitative mass spectrometry was used to monitor differences in protein expression levels across the cell lines.

Based on the CETSA measurements, resistant cells clearly showed a higher drug dose threshold as compared to the parent cell lines, typically requiring 8-50 times higher dose to establish similar target engagement. Several potential mechanism for drug resistant emerged - we, for example, observed up-regulation of thymidylate synthase and down regulation of reduced folate carrier (RFC) protein associated with antifolate transport, in some resistant cell lines.

The data supports that CETSA is a potential valuable tool to dissect various mechanisms those contribute to resistant development in cancer cells.

Citation Format: Lekshmy Kunjamma Usha Sreekumar, Yan Ting Lim, Saranya Veerappan, Par Nordlund. Exploring the potential of cellular thermal shift assay (CETSA) to study drug resistance during cancer therapy [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 2045. doi:10.1158/1538-7445.AM2017-2045
Abstract 2047: The muscarinic receptor antagonist, benztropine, blocks the expansion of a temozolomide resistant subpopulation of glioma cells
Authors: Bonnin Damian A. Almiron , Howard Joseph M. , Young Alison L. , Israel Mark A. , Havrda Matthew C.
Published: July 2017

Virtually all malignant gliomas become drug-resistant and recur after initial treatment, recurrent tumors are fatal within two-years, and no therapies exist that cure gliomas. The recognition that subpopulations of primitive cells with an oligodendrocyte precursor-like (OPC-like) phenotype capable of resisting standard therapy and contributing to recurrence, frames the question of whether adjuvant therapies designed to modify or eliminate OPC-like cells could slow the progression of glioma. Agents that force the differentiation of treatment-resistant OPC-like glioma cells, a phenomenon that requires cessation of proliferation, are compelling candidates for targeting OPC-like GSCs. Recently, it was observed that OPC proliferation was driven by activation of the M1, M3 and M4 muscarinic receptors. In another report, a large-scale drug screen designed to seek drugs to induce OPC differentiation in the context of multiple sclerosis identified a muscarinic receptor antagonist, benztropine (a.k.a. Cogentin), as a promoter of OPC differentiation and cell cycle exit. We have conducted studies in glioma cell lines supporting a role for benztropine in suppressing the development of drug-resistance to the standard glioma chemo-therapeutic temozolomide (TMZ). Upon treatment with TMZ, we identified the emergence of an OPC-like subpopulation of glioma cells identifiable by the co-expression of CD44, CD15 and PDGFRa. Treatment with pre-inhibitory doses of benztropine significantly reduced the TMZ IC50 in all glioma lines examined in association with blocking emergence of the CD44/CD15/PDGFR-positive subpopulation. Ongoing studies are designed to determine the tumor initiating potential of the CD44/CD15/PDGFR-positive subpopulation and whether benztropine will suppress the development of TMZ resistance in animal models of glioma.

Citation Format: Damian A. Almiron Bonnin, Joseph M. Howard, Alison L. Young, Mark A. Israel, Matthew C. Havrda. The muscarinic receptor antagonist, benztropine, blocks the expansion of a temozolomide resistant subpopulation of glioma 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 2047. doi:10.1158/1538-7445.AM2017-2047
Abstract 2051: LSTRA cell line as a model for large granular lymphocytic leukemia in drug screening
Authors: Chueh Fu-Shin , Chueh Fu-Yu , Yu Chao-Lan
Published: July 2017

Large granular lymphocytic (LGL) leukemia is a rare form of leukemia that is caused by the increase in cytotoxic T-lymphocytes or natural killer (NK) cells. A subcategory of T-LGL leukemia that co-expresses T and NK cell surface markers is very aggressive and has a very poor prognosis. Current treatment of aggressive T-LGL is based on non-specific immunosuppressive therapy. Lack of model cell lines contributes to slow progress in designing targeted therapy and clinical trials. Our recent studies demonstrate that the mouse T-leukemic cell line LSTRA reproduces some important characteristics of aggressive T-LGL leukemia. This is the first report of a cell line model mimicking the deadly human leukemia and has great potentials for drug screening in treating T-LGL leukemia.

Bortezomib is one of the drugs that show promising results in treating LGL leukemia patients in clinical trials. Bortezomib is the first FDA-approved reversible proteasome inhibitor in treating multiple myeloma and mantle cell lymphoma patients. One of the major concerns in using single-agent bortezomib is that patients develop resistance during the course of treatment and cancers relapse. Therefore, it is important to develop novel strategies in overcoming LGL leukemic cells’ resistance to bortezomib and its derivatives.

In our current study, we showed that bortezomib inhibited cell proliferation and induced apoptosis in LSTRA leukemic cells. Partial reversion after 48-72 hr of bortezomib treatment suggested development of resistance to bortezomib. We further established bortezomib-resistant LSTRA cells that tolerated significantly higher levels of bortezomib. Both carfilzomib (FDA-approved second generation irreversible proteasome inhibitor) and MLN 4924 (proteasome pathway upstream inhibitor) failed to overcome bortezomib resistance. Only luteolin, a common flavonoid found in plants, can effectively overcome bortezomib resistance.

Metabolic reprogramming has been linked to drug resistance in cancer cells. Indeed, We found that bortezomib-resistant LSTRA cells had smaller cell size as well as reduced rate of glucose uptake, lactate secretion, and mitochondrial respiration. These results suggest that reduced mitochondrial activity may be an important molecular marker for LSTRA cell’s resistance to bortezomib. All together, we identified luteolin as a potential small molecule in overcoming LGL leukemia’s resistance to proteasome inhibitor therapy. Altered mitochondrial activity and cell metabolism in bortezomib-resistant cells provide additional targets in developing novel combined chemotherapy for cancer patients.

Citation Format: Fu-Shin Chueh, Fu-Yu Chueh, Chao-Lan Yu. LSTRA cell line as a model for large granular lymphocytic leukemia in drug screening [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 2051. doi:10.1158/1538-7445.AM2017-2051
Abstract 2059: Co-treatment of XL019, a selective Jak2 inhibitor, highly sensitizes drug-resistant cancer cells by increasing P-gp inhibition
Authors: Cheon Ji Hyun , Park Yu Jin , Son Ji Yeon , Yoon Sung Pil , Kim Hyung Sik
Published: July 2017

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Co-treatment of XL019, a selective Jak2 inhibitor, highly sensitizes drug-resistant cancer cells by increasing P-gp inhibition

Ji Hyun Cheon1, Yu Jin Park, Ji Yeon Son, Sung Pil Yoon, and Hyung Sik Kim

Lab of molecular of toxicology, School of Pharmacy, Sungkyunkwan University, Suwon, South Korea

A high expression of P-glycoprotein (P-gp) is consistently observed in multidrug resistance (MDR) cancer cells. The purpose of our study was to identify conditions that would increase the sensitivity of P-gp-overexpressing drug-resistant KBV20C cancer cell line. We used commercially available epigenetic library, which includes 128 compounds. Using cellular viability test, we identified that XL019 highly sensitized KBV20C-resistant cells to vincristine treatment. However, XL019-induced sensitization was not observed in vincristine-treated sensitive KB parent cells, suggesting that these effects are specific to resistant cancer cells. Using FACS analysis, western-blot, and annexin V staining, we identified that XL109 sensitized vincristine-treated KBV20C cells via apoptosis and G2 arrest. Furthermore, sensitization potency of XL109 in combination with vincristine was measured in KBV20C cells when comparing with P-gp inhibitor verapamil or another Jak2 inhibitor CEP-33779. We further investigated the mechanisms of XL109 against sensitization of vincristine-treated KBV20C cells. The sensitization mechanism of XL109 was mainly depends on the inhibition of P-gp. In addition, ATPase activity was also conducted to identify as potential role of XL019 in P-gp inhibition. In the docking modeling, XL019 and CEP-33779 showed high binding affinity docking score against ABCB1 receptor protein by -10.590 and -9.104, respectively. Collectively, inhibition of P-gp by XL109 can increase the vincristine-sensitivity in MDR cancer cells through increased apoptosis and G2 arrest. Our findings indicate that Jak2 inhibitor may be a promising target in the treatment of patients resistant to anti-mitotic drug.

Note: This abstract was not presented at the meeting.

Citation Format: Ji Hyun Cheon, Yu Jin Park, Ji Yeon Son, Sung Pil Yoon, Hyung Sik Kim. Co-treatment of XL019, a selective Jak2 inhibitor, highly sensitizes drug-resistant cancer cells by increasing P-gp 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 2059. doi:10.1158/1538-7445.AM2017-2059
Abstract 2062: Inhibition of STAT3 overcomes gemcitabine resistance in pancreatic cancer cells
Authors: Chen Chi-Wei , Wu Ruiqin , Meng Yunxiao , Zhu Wenge
Published: July 2017

Gemcitabine is used as the first line treatment of pancreatic ductal adenocarcinoma (PDAC), however, either innate or acquired resistance to gemcitabine limit its therapeutic efficacy. In this study, several DNA damage agents including DNA repair inhibitors, and kinase inhibitors were examined for suppression of cell growth of gemcitabine resistant cells. The results show that most of these compounds are cross-resistant to gemcitabine-resistant pancreatic cells. By using STRING protein network database, we found that STAT3 signaling pathway plays a connectional role to link targeted proteins we tested. Interestingly, gemcitabine-resistant pancreatic cells have higher level of phosphor-STAT3 (pSTAT3) and are more sensitive to STAT3 inhibitor, S3I-201. Furthermore, combined S3I-201 with gemcitabine synergically suppresses the growth of both cell lines in vitro. We also confirmed the therapeutic efficacy of combined treatments using xenografted model. Taken together, inhibition of STAT3 overcomes gemcitabine resistance in pancreatic cancer cells. This study may provide us with a new approach to treat pancreatic cancer as well as gemcitabine resistance of pancreatic cancer.

Citation Format: Chi-Wei Chen, Ruiqin Wu, Yunxiao Meng, Wenge Zhu. Inhibition of STAT3 overcomes gemcitabine resistance in pancreatic cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2062. doi:10.1158/1538-7445.AM2017-2062