bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract A03: Formins stabilize cell-ECM adhesions during invasion onset
Authors: Fessenden Tim , Beckham Yvonne , Perez-Neut Mathew , Juan Guillermina Ramirez-San , Gardel Margaret L.
Published: March 2017

The onset of local invasion typically defines the transition from benign to malignant tumors. This pathological definition has clear implications for cell behaviors governing invasion onset, which nonetheless remain mysterious. Thus we asked whether established cytoskeletal regulators contributed specifically to invasion in multicellular ensembles.

We investigated roles of actin nucleators from the formin family and the Arp2/3 complex during collective invasion by two cell types: tumor explants from PyMT mice, and acini of Manin-Darby Canine Kidney (MDCK) cells, which initiate collective invasion in response to Hepatocyte Growth Factor (HGF). Contrary to our expectations, inhibition of Arp2/3 did not prevent invasion in either cell type. The pan-formin inhibitor SMIFH2, however, drastically reduced invasive fronts in both cell types. This phenotype was specific to 3D invasion, as formins were dispensable for 2D motility by single cells or cell collectives.

We identified Diaphanous 1 (Dia1) and FHOD1 as formin family members required for invasion by MDCK acini. Live imaging of Dia1 knockdown acini revealed that while they formed transient extensions into the collagen, these were too unstable to support invasion.

Despite these defects, Dia1 knockdown cells could deform the collagen matrix locally and exerted traction stresses equal to controls. Stiffer, bundled collagen gels potentiated invasion by control acini but could not rescue invasion by Dia1 knockdown acini.

We then imaged acini in which GFP-Lifeact and mCherry-Myosin Light Chain were coexpressed as they invaded into labelled collagen. During invasion onset, we observed formation of subcellular actomyosin puncta on minute timescales. These puncta could adhere stably and alter collagen even while the cell continued to change shape and migrate within the acinus. Such adhesions formed rarely and with unstable dynamics in Dia1 knockdown acini.

Thus formins may contribute to malignancy through molecular and physical mechanisms distinct from overall cell contractility. Rather, they mediate invasion in 3D contexts where competing cell-cell and cell-ECM interactions make stringent local requirements of adhesion stability. This work provides a bridge between cell motility in 3D and canonical models of 2D migration.

Citation Format: Tim Fessenden, Yvonne Beckham, Mathew Perez-Neut, Guillermina Ramirez-San Juan, Margaret L. Gardel. Formins stabilize cell-ECM adhesions during invasion onset. [abstract]. In: Proceedings of the AACR Special Conference on Engineering and Physical Sciences in Oncology; 2016 Jun 25-28; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2017;77(2 Suppl):Abstract nr A03.
Abstract A13: Predictive computational modeling to define effective treatment strategies for bone metastatic prostate cancer
Authors: Cook Leah , Araujo Arturo , Pow-Sang Julio , Budzevich Mikalai , Basanta David , Lynch Conor C.
Published: March 2017

The ability to rapidly assess the efficacy of therapeutic strategies for incurable bone metastatic prostate cancer is an important and urgent need. Pre-clinical in vivo models provide insights yet are limited in their capacity to interrogate temporal multi-cellular interactions occurring in the cancer-bone microenvironment. Computational and mathematical models that integrate and, are validated experimentally, can overcome this limitation and accelerate biological research. Here, we describe how a biologically driven discrete continuum hybrid cellular automaton (HCA) model approach can dissect the pleiotropic effects of inhibiting putative therapeutic targets such as, TGFβ. Using our HCA model, we tested five different therapeutic doses delivered in two therapeutic windows. In silico results predict that TGFβ inhibition, applied prior to tumor seeding acts by directly impacting prostate cancer cell viability but also by simultaneously restricting osteoclast formation and unexpectedly, promoting osteoblast differentiation. This effect was dependent on the prostate cancer cell expression of TGFβ receptors. In silico predictions were validated with two independent in vivo models of bone metastatic prostate cancer (PAIII and C4-2B). Using immunohistochemical information from human bone metastatic prostate cancer samples, we also demonstrate how the HCA can be used to predict the evolution of heterogeneous disease in response to applied therapies. Collectively, these data underscore the power of a combined HCA/biological approach in optimizing the efficacy of applied therapies and measuring their impact on bone metastatic prostate cancer.

Citation Format: Leah Cook, Arturo Araujo, Julio Pow-Sang, Mikalai Budzevich, David Basanta, Conor C. Lynch. Predictive computational modeling to define effective treatment strategies for bone metastatic prostate cancer. [abstract]. In: Proceedings of the AACR Special Conference on Engineering and Physical Sciences in Oncology; 2016 Jun 25-28; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2017;77(2 Suppl):Abstract nr A13.
Abstract A17: Genomic analysis and simulation for understanding heterogenous cancer evolution
Authors: Niida Atsushi , Takahashi Yusuke , Uchi Ryutaro , Mimori Koshi , Miyano Satoru
Published: March 2017

A malignant tumor harbors multiple clones generated by branching evolution. This phenomenon, called intratumor heterogeneity, could foster evolutionary adaptation and presumably causes therapeutic failure. To investigate intratumor heterogeneity in colorectal cancer, we performed whole exome sequencing of samples obtained from geographically separated regions in a single colorectal tumor. The multiregional sequencing showed early-acquired mutations, which was shared by all regions as well as late-acquired mutations, which shaped extensive intratumor heterogeneity. Next, to explore the principles underlying the intratumor heterogeneity, we built a cellular automaton model, termed the BEP model, which can simulate the branching evolution in silico. We then extensively searched for conditions that reproduce the multiregional sequencing data by performing simulations with various parameter settings on a supercomputer. The simulation analysis suggested that neutral evolution boosted by high mutation rate can extensive intratumor heterogeneity. Collectively, This study identified the possible principle underlying intratumor heterogeneity, which provides novel insights into the origin of cancer robustness and evolvability.

Citation Format: Atsushi Niida, Yusuke Takahashi, Ryutaro Uchi, Koshi Mimori, Satoru Miyano. Genomic analysis and simulation for understanding heterogenous cancer evolution. [abstract]. In: Proceedings of the AACR Special Conference on Engineering and Physical Sciences in Oncology; 2016 Jun 25-28; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2017;77(2 Suppl):Abstract nr A17.
Abstract A29: Heterogeneity of androgen receptor dynamics and drug response in prostate cancer cells
Authors: Patsch Katherin , Soundararajan Anjana , Engeln Mark , Gross Mitchell E. , Mumenthaler Shannon M. , Ruderman Daniel
Published: March 2017

Background: Recent studies suggest that the spatio-temporal dynamics of critical signaling molecules can mediate heterogeneous response to therapeutic intervention. Here, we set out to apply live cell imaging of single cells in high throughput to correlate the dynamics of androgen receptor (AR) with response to taxane chemotherapy in heterogeneous prostate cancer (PCa) cell populations.

Methods: We previously developed a 3-step high throughput imaging and data analysis workflow to improve measurements of the dynamic phenotype in heterogeneous populations. We treated PCa cells stably expressing GFP-AR with AR ligand and quantified nuclear/cytoplasmic GFP intensity to measure nuclear translocation of AR over a 30 min time course. Then we treated cells with paclitaxel and tracked cells' response for 24h.

Results: Applied to PCa cell lines stably expressing GFP-AR, we measured considerable heterogeneity of AR translocation in response to ligand stimulation. We quantified populations of non-responders and classified responding cells based on the dynamics of AR. Evaluation of cell morphology revealed a fraction of relatively large cells to be exclusively slow responders to AR ligand. We measured heterogeneous response to treatment with paclitaxel that correlated with cell phenotype.

Conclusion: We conclude that cell morphology features in heterogeneous PCa cell populations correlate with AR translocation dynamics and drug response. Future experiments will include expression of the constitutively active AR variant AR-v7 to analyze its effect on the dynamics of wild-type AR and on single cell response to paclitaxel chemotherapy.

Note: This abstract was not presented at the conference.

Citation Format: Katherin Patsch, Anjana Soundararajan, Mark Engeln, Mitchell E. Gross, Shannon M. Mumenthaler, Daniel Ruderman. Heterogeneity of androgen receptor dynamics and drug response in prostate cancer cells. [abstract]. In: Proceedings of the AACR Special Conference on Engineering and Physical Sciences in Oncology; 2016 Jun 25-28; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2017;77(2 Suppl):Abstract nr A29.
Abstract A31: Early signaling dynamics of the epidermal growth factor receptor
Authors: Reddy Raven J.
Published: March 2017

Despite extensive study of the EGF receptor (EGFR) signaling network, the immediate posttranslational changes that occur in response to growth factor stimulation remain poorly characterized; as a result, the biological mechanisms underlying signaling initiation remain obscured. To address this deficiency, we have used a mass spectrometry-based approach to measure system-wide phosphorylation changes throughout the network with 10-s resolution in the 80 s after stimulation in response to a range of eight growth factor concentrations. Significant changes were observed on proteins far downstream in the network as early as 10 s after stimulation, indicating a system capable of transmitting information quickly. Meanwhile, canonical members of the EGFR signaling network fall into clusters with distinct activation patterns. Src homology 2 domain containing transforming protein (Shc) and phosphoinositol 3-kinase (PI3K) phosphorylation levels increase rapidly, but equilibrate within 20 s, whereas proteins such as Grb2-associated binder-1 (Gab1) and SH2-containing tyrosine phosphatase (SHP2) show slower, sustained increases. Proximity ligation assays reveal that Shc and Gab1 phosphorylation patterns are representative of separate timescales for physical association with the receptor. Inhibition of phosphatases with vanadate reveals site-specific regulatory mechanisms and also uncovers primed activating components in the network, including Src family kinases, whose inhibition affects only a subset of proteins within the network. The results presented highlight the complexity of signaling initiation and provide a window into exploring mechanistic hypotheses about receptor tyrosine kinase (RTK) biology.

Note: This abstract was not presented at the conference.

Citation Format: Raven J. Reddy. Early signaling dynamics of the epidermal growth factor receptor. [abstract]. In: Proceedings of the AACR Special Conference on Engineering and Physical Sciences in Oncology; 2016 Jun 25-28; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2017;77(2 Suppl):Abstract nr A31.
Abstract A33: An individualized predictive 3D model of tumor response to topotecan for a patient-derived orthotopic xenograft model of pediatric neuroblastoma
Authors: Shirinifard Abbas , Thiagarajan Suresh , Patel Yogesh T. , Davis Abigail D. , Jacus Megan O. , Roberts Jessica , Stewart Clinton F. , Sablauer András
Published: March 2017

Resistance to chemotherapeutics and targeted therapies in pediatric solid tumors including neuroblastoma is a common cause of poor clinical outcome. These failures in part stem from shortcomings in understanding inter- and intra-tumor heterogeneities of drug penetration due to heterogeneities in blood perfusion. Herein we present an individualized predictive three-dimensional (3D) model of tumor response to topotecan (TPT) for a patient-derived orthotopic xenograft model of pediatric NB5 neuroblastoma. This model is integrated with an individualized physiologically-based pharmacokinetic (PBPK) model of TPT and accounts for the effects of inter- and intra-tumor heterogeneities in blood perfusion on tumor response. This model uses a set of 3D reaction-diffusion equations to simulate transport of TPT from blood vessels into the tumor tissue and its flux in and out of intracellular space. The transport model takes inputs from three spatial scales (systemic, tissue and cells) to predict TPT exposure maps defined over the volume of an individual tumor: a) plasma concentration-time profiles from an individualized physiologically-based pharmacokinetic (PBPK) model of TPT, b) 3D blood perfusion map of the individual tumor from contrast enhanced ultrasound (CEUS) using VEVO 2100 imaging system, and c) in vitro TPT cellular uptake and efflux kinetics from two-photon imaging. The transport model also gives feedback to the PBPK model. We use in vitro pharmacodynamics (PD) experiments with NB5 cells exposed to TPT to derive probabilistic PD-rules for drug effects (γ-H2AX response). Based on these rules and exposure maps predicted by the transport model, we then compute probabilities of effects for the entire tumor volume. We validate the predicted drug effect maps by comparing them to observed effect data (from three dosage levels) measured by immunohistochemistry marker for γ-H2AX from the same tumor (location matched serial sections) using spatial correlation techniques.

Citation Format: Abbas Shirinifard, Suresh Thiagarajan, Yogesh T. Patel, Abigail D. Davis, Megan O. Jacus, Jessica Roberts, Clinton F. Stewart, András Sablauer. An individualized predictive 3D model of tumor response to topotecan for a patient-derived orthotopic xenograft model of pediatric neuroblastoma. [abstract]. In: Proceedings of the AACR Special Conference on Engineering and Physical Sciences in Oncology; 2016 Jun 25-28; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2017;77(2 Suppl):Abstract nr A33.
Abstract A36: Study of stromal mechanoregulation of tumor metabolism and growth dynamics
Authors: Anderson Michael , Celli Jonathan , El-Hamidi Hamid
Published: March 2017

As tumors develop and mature they are subjugated to compressive forces and a rigid stroma. This is particularly true in pancreatic cancer where its defining feature is a particularly rigid and fibrous stroma. The mechanical properties of the stroma can have a large influence on the growth behavior and invasiveness of tumors. An intriguing recent example of this is that the PI3K pathway is activated via integrin engagement on a rigid stroma and can affect some metabolic pathways. What makes this exciting is that both the stromal stiffness and reprogrammed metabolism have long been known to be features of cancer and this showed that these features may be intertwined in a feedback loop. From another angle, tumors are subjugated to high compressive forces and many have shown that this force can alter spheroid growth dynamics and shift cells to a more invasive phenotype. While compressive stress on spheroid growth certainly influences its growth dynamics, it is unclear whether it is due to stress or strain on the spheroid. Additionally, it implicates compressive force in altering the cellular metabolism as well. Going a step further, extracellular acidity is a well-known phenotype of solid tumors and is intrinsically linked to an altered metabolism. To study this feedback loop between stromal mechanical properties and metabolism/acidity we will utilize two different models alongside the pH dependent fluorophore, SNARF. The first is a hybrid gel model that is constructed of a base polyacrylamide (PA) layer that is covalently bound to select ECM proteins such as matrix gel and collagen. The second is a spheroid embedded in agarose model in which a base coat of agarose is applied to the bottom of each well in a multiwall plate and after setting, an ungelled mixture of spheroids, agarose and fluorescently labelled latex beads are poured over the base coat and allowed to set. The agarose is bio inert and cannot be broken down by cells. Thus it effectively acts like a compressible, non-integrin activating, isotropic media that completely surrounds the embedded spheroid. To study the cell packing density we will explore a model that predicts strain on an embedded spheroid due to compressive stress drives the cell density in spheroids. To experimentally explore this model, we will use the spheroid embedded in agarose model and vary starting implanted spheroid sizes, but remove them from the agarose at identical stress levels. All of this together will lead us to a better understanding of how the cell metabolism/pHe and tumor cell packing are mechanoregulated by the stroma.

Citation Format: Michael Anderson, Jonathan Celli, Hamid El-Hamidi. Study of stromal mechanoregulation of tumor metabolism and growth dynamics. [abstract]. In: Proceedings of the AACR Special Conference on Engineering and Physical Sciences in Oncology; 2016 Jun 25-28; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2017;77(2 Suppl):Abstract nr A36.
Abstract A48: Computational modeling of vessel growth and blood flow in the tumor microvasculature
Authors: Lee Tae-Rin , Yoo Sung Sic , Jo Junhong , Go Anna , Seo Hyung-Kwon
Published: March 2017

Tumor-induced angiogenesis is important to understand the mechanism of tumor growth. However, due to its heterogeneous microenvironment, it is challenging to elucidate the correlation between tumor growth and angiogenesis. In this talk, we develop a computational model of tumor-induced angiogenesis with blood flow. The complex steps of angiogenesis are expressed by mathematical models from diffusion of growth factor, sprouting from existing vessels, vessel growth and anastomosis. Furthermore, the blood flow in the new vessels is simulated by using one dimensional flow model with hematocrit redistribution. First of all, the computational model will be validated by comparing with experimental data. In addition, the developed model will be tested in predicting tumor-induced angiogenesis with different model parameters. Finally, the future perspectives of computational modeling in tumor-induced angiogenesis will be fully discussed.

Note: This abstract was not presented at the conference.

Citation Format: Tae-Rin Lee, Sung Sic Yoo, Junhong Jo, Anna Go, Hyung-Kwon Seo. Computational modeling of vessel growth and blood flow in the tumor microvasculature. [abstract]. In: Proceedings of the AACR Special Conference on Engineering and Physical Sciences in Oncology; 2016 Jun 25-28; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2017;77(2 Suppl):Abstract nr A48.
Abstract A62: Unjamming and spreading of a cellular aggregate as a model of breast cancer migration
Authors: Wang Karin , Fredberg Jeffrey J.
Published: March 2017

Traditional understanding holds that metastasis begins as tumor cells undergo epithelial-to-mesenchymal transition (EMT) to migrate and escape. Recent studies suggest that EMT is not necessary for metastasis, however. Tumor cells may retain their epithelial phenotype to migrate collectively during metastasis. But if EMT is not the crucial permissive step, what is?

Our group recently discovered cellular jamming; a process by which an epithelial layer is dormant, non-migratory, and solid-like, corresponding to the jammed state, but in other circumstances becomes active, migratory, and fluid-like, corresponding to the unjammed state. Therefore, based on this phenomenon, do breast cancer cells unjam before they can collectively migrate and metastasize? Spheroidal aggregates of MCF10A and MDA-MB-231 cells spreading on collagen-coated polyacrylamide gels, modeling normal and malignant breast epithelium, respectively, were used to investigate cell jamming, cell-matrix adhesion, and associated traction forces.

Compared with MCF10A spheroids, MDA-MB-231 spheroids permeated more rapidly onto gels, generated largely localized traction forces, and dissociated to spread more rapidly outwards. These results suggest MDA-MB-231 cells are more susceptible to unjamming and collective migration. This work will provide a new framework by which to explain collective cellular behavior of normal and malignant breast epithelium.

Citation Format: Karin Wang, Jeffrey J. Fredberg. Unjamming and spreading of a cellular aggregate as a model of breast cancer migration. [abstract]. In: Proceedings of the AACR Special Conference on Engineering and Physical Sciences in Oncology; 2016 Jun 25-28; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2017;77(2 Suppl):Abstract nr A62.
Abstract B13: High-content imaging to quantitate colorectal cancer associated fibroblast heterogeneity
Authors: Garvey Colleen M. , Chen Oscar , Lau Roy , Mumenthaler Shannon M.
Published: March 2017

Cancer-associated fibroblasts (CAFs) are an important component of the tumor microenvironment known to influence various aspects of tumor progression, including response to therapy. However, this stromal cell subtype is extremely heterogeneous, both between and within individual tumors. Targeting of the CAF population has not been successful in the clinical setting, which could be due in part to the myriad of functions of different CAF subpopulations. In order to elucidate the overall implications of CAF heterogeneity, we gathered quantitative phenotypic data using a novel high-content imaging platform. Specifically, we calculated several morphological parameter values and estimated birth and death rates of individual populations of CAFs isolated from colorectal cancer patients. We also performed co-culture experiments with tumor cells and characterized the influence of different CAF populations on tumor evolutionary dynamics (i.e. birth and death rates) in response to drug treatment. Further, these features were correlated to molecular analyses (i.e. -smooth muscle actin and fibroblasts activated protein expression) and patient outcome (i.e. sites of metastasis). We observed high levels of heterogeneity in cell area and cell roundness as well as altered rates of growth in response to perturbations in oxygen levels. This quantitative method for investigating multiple cellular phenotypes provides novel insight into patient-level heterogeneity and its possible implications on response to drug.

Citation Format: Colleen M. Garvey, Oscar Chen, Roy Lau, Shannon M. Mumenthaler. High-content imaging to quantitate colorectal cancer associated fibroblast heterogeneity. [abstract]. In: Proceedings of the AACR Special Conference on Engineering and Physical Sciences in Oncology; 2016 Jun 25-28; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2017;77(2 Suppl):Abstract nr B13.
Abstract B14: The effect of sunitinib treatment in human melanoma xenografts: Associations with angiogenic profiles
Authors: Gaustad Jon-Vidar , Simonsen Trude G. , Andersen Lise Mari K. , Rofstad Einar K.
Published: March 2017

The effect of antiangiogenic agents targeting the vascular endothelial growth factor A (VEGF-A) pathway has been reported to vary substantially in preclinical studies. Treatments with these agents have induced substantial reductions in vessel density in some tumor models, and minor or no reductions in vessel density in others. Additionally, the treatments have improved vascular function and oxygenation in some tumor models, and induced hypoxia in others. The purpose of this study was to investigate the effect of sunitinib treatment on the morphology and function of tumor vasculature in melanoma xenografts with different angiogenic profiles.

A-07, U-25, D-12, and R-18 melanoma xenografts grown in dorsal window chambers were used as preclinical tumor models. Tumor-bearing mice were treated with sunitinib (40 mg/kg/day) or vehicle. Morphologic parameters of tumor vascular networks were assessed from high-resolution transillumination images, and tumor blood supply times were assessed from first-pass imaging movies recorded after a bolus of 155 kD tetramethylrhodamine isothiocyanate-labeled dextran was injected intravenously. Tumor hypoxia was assessed in immunohistochemical preparations by using pimonidazole as hypoxia marker, and the gene expression and the protein secretion rate of angiogenic factors were assessed by quantitative PCR and ELISA, respectively.

The melanoma lines differed substantially in the expression of VEGF-A, VEGF-C, and platelet-derived growth factor A. Sunitinib treatment reduced vessel densities and induced hypoxia in all melanoma lines, and the magnitude of the effect was associated with the gene expression and protein secretion rate of VEGF-A. Sunitinib treatment also increased vessel segment lengths, reduced the number of small-diameter vessels, and inhibited growth-induced increases in the diameter of surviving vessels, but did not affect blood supply times.

In conclusion, sunitinib treatment did not improve vascular function but reduced vessel density and induced hypoxia in human melanoma xenografts. The magnitude of the treatment-induced effect was associated with the angiogenic profiles of the melanoma lines.

Citation Format: Jon-Vidar Gaustad, Trude G. Simonsen, Lise Mari K. Andersen, Einar K. Rofstad. The effect of sunitinib treatment in human melanoma xenografts: Associations with angiogenic profiles. [abstract]. In: Proceedings of the AACR Special Conference on Engineering and Physical Sciences in Oncology; 2016 Jun 25-28; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2017;77(2 Suppl):Abstract nr B14.
Abstract B37: Photothermal therapy of glioblastoma multiforme using multiwalled carbon nanotubes optimized for diffusion in extracellular space
Authors: Eldridge Brittany , Bernish Brian , Fahrenholtz Cale , Singh Ravi
Published: March 2017

Glioblastoma multiforme (GBM) is the most common and most lethal primary brain tumor with a 5 year overall survival rate of approximately 5%. Currently, no therapy is curative and all have significant side effects. Focal thermal ablative therapies that heat malignant tissue to ablative temperatures (>55°C) to induce tumor cell death are being investigated as a novel treatment modality. Such thermal ablative therapies can be enhanced by using nanotechnology, with the addition of nanoparticles. Carbon nanotube mediated thermal therapy (CNMTT) uses lasers that emit near infrared radiation to excite carbon nanotubes (CNTs) localized to the tumor volume to generate localized heat needed for thermal ablation. Clinical translation of CNMTT for GBM will require development of effective strategies to deliver CNTs to tumors, clear structure-activity and structure-toxicity evaluation, and an understanding of the effects of inherent and acquired thermotolerance on the efficacy of treatment. In our studies, we look at the effects of different coatings on multiwalled CNT (MWCNTs) diffusion and show that a dense coating of phospholipid-poly(ethylene glycol) on MWCNTs allows for better diffusion through brain ECM-mimicking hydrogels, while maintaining the ability to achieve ablative temperatures after laser exposure. We investigate the effects of phospholipid-poly(ethylene glycol) coated MWCNTs on the heat shock response in GBM and show that they do not induce a HSR in GBM cell lines. Activation of the HSR in GBM cells via exposure to sub-ablative temperatures or short term treatment with an inhibitor of heat shock protein 90 (17-(dimethylaminoethylamino)-17-demethoxygeldanamycin (17-DMAG)), induces a protective heat shock response that results in thermotolerance and protects against CNMTT. Finally, we evaluate the potential for CNMTT to selectively heat GBM multicellular spheroids comparing different methods of heat generation in a three dimensional spheroid model. These data provide pre-clinical insight into key parameters needed for translation of CNMTT including nanoparticle delivery through a three-dimensional volume, cytotoxicity, and efficacy for treatment of thermotolerant GBM.

Citation Format: Brittany Eldridge, Brian Bernish, Cale Fahrenholtz, Ravi Singh. Photothermal therapy of glioblastoma multiforme using multiwalled carbon nanotubes optimized for diffusion in extracellular space. [abstract]. In: Proceedings of the AACR Special Conference on Engineering and Physical Sciences in Oncology; 2016 Jun 25-28; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2017;77(2 Suppl):Abstract nr B37.
Abstract B57: RNAi Nanotechnology for Cancer Target Validation and Therapy
Authors: Shi Jinjun
Published: March 2017

RNA interference (RNAi) represents a promising strategy for identification and validation of putative therapeutic targets, and for treatment of a myriad of important human diseases including cancer. The ubiquitous application of RNAi in cancer research and therapy is nevertheless hindered by the challenge of effective systemic in vivo delivery of RNAi agents (e.g., siRNA) to solid tumors, which requires overcoming of multiple physiological barriers, such as enzymatic degradation, rapid elimination by renal excretion or by the mononuclear phagocyte system (MPS), poor tumor penetration, and insufficient cellular uptake and endosomal escape. Here we will describe the rational design and development of unique nanoparticle platforms to address these obstacles. These siRNA nanoparticles have been successfully applied to evaluate the therapeutic role of different targets (e.g., prohibitin1) in treating solid tumors, and have demonstrated significant potential for the clinical development of novel cancer therapies.

Note: This abstract was not presented at the conference.

Citation Format: Jinjun Shi. RNAi Nanotechnology for Cancer Target Validation and Therapy. [abstract]. In: Proceedings of the AACR Special Conference on Engineering and Physical Sciences in Oncology; 2016 Jun 25-28; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2017;77(2 Suppl):Abstract nr B57.
Abstract B61: Intratumoral oxygen gradients mediate sarcoma cell invasion
Authors: Lewis Daniel M. , Park Kyung Min , Eisinger-Mathason T.S. Karin , Simon Celeste , Gerecht Sharon
Published: March 2017

Hypoxia is a critical factor in the progression and metastasis of many cancers including soft tissue sarcomas. Frequently, oxygen (O2) gradients develop in tumors as they grow beyond their vascular supply leading to heterogeneous areas of O2 depletion. Here we report the impact of hypoxic O2 gradients on sarcoma cell invasion and migration. O2 gradient measurements showed that large sarcoms mouse tumors (>300mm3) contain a severely hypoxic core (≤0.1% pO2) whereas smaller tumors possessed hypoxic gradients throughout the tumor mass (0.1%-6% pO2). To analyze tumor invasion, we utilized O2-controllable hydrogels to recreate the physio-pathological O2 levels in vitro. Small tumor grafts encapsulated in the hydrogels revealed increased invasion that was both faster and extended over a longer-distance in the hypoxic hydrogels compared to nonhypoxic hydrogels. To accurately model the effect of the O2 gradient, we examined individual sarcoma cells embedded in the O2-controllable hydrogel. We observed that hypoxic gradients guide sarcoma cell motility and matrix remodeling through HIF1α activation. We further found that in the hypoxic gradient, individual cells migrate more quickly, across longer distances, and in the direction of increasing O2 tension. Treatment with minoxidil, inhibitor of hypoxia-induced sarcoma metastasis, abrogated cell migration and matrix remodeling in the hypoxic gradient. Overall, we show that O2 acts as a 3D physico-tactic agent during sarcoma tumor invasion and propose the O2-controllable hydrogels as a predictive system to study early stages of the metastatic process and therapeutic targets.

Citation Format: Daniel M. Lewis, Kyung Min Park, T.S. Karin Eisinger-Mathason, Celeste Simon, Sharon Gerecht. Intratumoral oxygen gradients mediate sarcoma cell invasion. [abstract]. In: Proceedings of the AACR Special Conference on Engineering and Physical Sciences in Oncology; 2016 Jun 25-28; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2017;77(2 Suppl):Abstract nr B61.
Abstract B62: Role of the blood microenvironment in the upregulation of oncoproteins in circulating pancreatic cancer cells
Authors: Mitrugno Annachiara , Pelz Katherine , Sears Rosalie , McCarty Owen
Published: March 2017

Background: Platelets are promoters of cancer cell proliferation at the metastatic niche, however the exact mechanism(s) by which platelets drive cancer cell proliferation remain ill-defined. The oncoprotein c-MYC, which governs neoplastic proliferation, is overexpressed in pancreatic tumors at the metastatic site as compared to primary tumors, with the overexpression of c-MYC indicative of a poor clinical outcome for patients with cancer. At present, the oncogenic pathways mediating c-MYC upregulation in metastatic cancer cells are largely unknown. Our exciting preliminary data demonstrate for the first time that platelets upregulate c-MYC protein levels in PANC-1 pancreatic cancer cells, suggesting a novel prometastatic role for platelets in pancreatic cancer.

Aims: To define the mechanisms by which platelets upregulate c-MYC protein levels in PANC-1 pancreatic cancer cells.

Methods: We utilized a co-culture platform to examine the effect of resting and thrombin-stimulated human platelets as well as platelet fractions (platelet-derived membrane bound molecules and soluble molecules) on c-MYC expression in PANC-1 cancer cells. Platelet inhibitors, including the GPIIbIIIa blocker Integrilin, were used to study the molecular mechanisms by which platelets upregulate c-MYC expression in cancer cells. Changes in c-MYC oncoprotein were detected by Western Blotting. The physical association between platelets and PANC-1 cancer cells was quantified by immunoblotting with an anti-GPIIb antibody against the platelet-specific integrin GPIIbIIIa.

Results: Resting and activated platelets as well as platelet fractions induced an upregulation of c-MYC expression in PANC-1 cancer cells. The effect of platelets on c-MYC expression was largely dependent on direct contact with the cancer cells, as the preincubation of platelets with Integrilin reduced platelet-induced c-MYC expression.

Conclusion: We show that the expression of c-MYC in PANC-1 cancer cells can be upregulated by platelets, revealing a novel mechanism of platelet action in the progression of cancer and suggesting that the overexpression of c-MYC at the metastatic niche may be inhibited through the use of platelet inhibitors. We are currently characterizing the molecular underpinnings of platelet-mediated c-MYC regulation with respect to the contribution of platelets to cancer cell proliferation and growth.

Citation Format: Annachiara Mitrugno, Katherine Pelz, Rosalie Sears, Owen McCarty. Role of the blood microenvironment in the upregulation of oncoproteins in circulating pancreatic cancer cells. [abstract]. In: Proceedings of the AACR Special Conference on Engineering and Physical Sciences in Oncology; 2016 Jun 25-28; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2017;77(2 Suppl):Abstract nr B62.
Abstract IA02: Advances in drug delivery
Authors: Langer Robert S.
Published: March 2017

Advanced drug delivery systems are having an enormous impact on human health. We start by discussing our early research on developing the first controlled release systems for macromolecules and the isolation of angiogenesis inhibitors and how these led to numerous new cancer therapies. New drug delivery technologies including nanoparticles and nanotechnology are now being studied for use treating cancer and other illnesses. We will also discuss novel super long acting oral drug delivery systems as well as ways of developing novel microchips for drug delivery and how they also can be used for designing personalized cancer drug regimens. Finally, we will discuss new approaches for cell therapy based on a novel method of “squeezing” materials into cells.

Citation Format: Robert S. Langer. Advances in drug delivery. [abstract]. In: Proceedings of the AACR Special Conference on Engineering and Physical Sciences in Oncology; 2016 Jun 25-28; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2017;77(2 Suppl):Abstract nr IA02.
Abstract IA04: Game theory and personalized cancer treatment
Authors: Austin Robert H.
Published: March 2017

The presence of driver mutations and subsequent clonal expansion by Darwinian evolution does not explain dormancy and re-emergence of cancer from a community of cancer and host cells (including stromal and immune cells). Dormancy appears to be a slow-driven, interaction-dominated, threshold system which is poorly prognosed. At the simplest level, we view cancer cells interacting with host cells via complex, non-linear population dynamics, which can lead to very non-intuitive but perhaps deterministic and understandable progression dynamics of cancer. We explore here the dynamics of host-cancer cell populations in the presence of (1) payoffs gradients and (2) perturbation due to cell migration to determine to what extent the time-dependence of the populations can be quantitatively understood in spite of the underlying complexity of the individual agents. The population dynamics presented here provide a model system for the clinic to map the payoffs matrices and suggest new avenues to predict drug dosages.

Citation Format: Robert H. Austin. Game theory and personalized cancer treatment. [abstract]. In: Proceedings of the AACR Special Conference on Engineering and Physical Sciences in Oncology; 2016 Jun 25-28; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2017;77(2 Suppl):Abstract nr IA04.
Abstract IA13: Imaging drug delivery and nanotherapeutics
Authors: Weissleder Ralph
Published: March 2017

Over 180 chemically distinct cancer drugs are currently in clinical use while new nanomaterials, small molecule inhibitors and newer immunotherapeutics are entering clinical trials. Preclinical testing usually involves measuring tumor sizes, survival endpoints, the use of histopathology and measurement of serum biomarkers. Yet, despite all of these advances, preciously little is known on how many of these compounds actually work (or fail) at the single cell level in vivo, what the spatial and temporal heterogeneity is and how efficacy can be improved. The latter is particularly vexing as the majority of patients show suboptimal responses and tumors often relapse within months-years. With the recent development of i) single cell in vivo imaging technology (Nat Commun 2013;4,1504), ii) fluorescent nanoparticles and encapsulated therapeutics (Science Transl Med, 2015;7:314; Nat Commun. 2015;6:8692), iii) in vivo reporters of host response, cell death or DNA damage (ChemMedChem, 2014;9:1131), iv) new computational analysis (Nat Methods, 2015;12:577), and v) armed with new biological insight from feasibility studies we are now able to address important cancer therapeutics questions in ways that were not previously possible. In this presentation I will review imaging approaches for the functional assessment of new therapeutics at the single cell level in vivo, addressing key questions on distribution (pharmacokinetics, PK) and specific cellular response (pharmacodynamics, PD).

Citation Format: Ralph Weissleder. Imaging drug delivery and nanotherapeutics. [abstract]. In: Proceedings of the AACR Special Conference on Engineering and Physical Sciences in Oncology; 2016 Jun 25-28; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2017;77(2 Suppl):Abstract nr IA13.
Abstract IA14: Imaging tumor metabolism with hyperpolarized 13C-labeled cell substrates
Authors: Brindle Kevin M.
Published: March 2017

Molecular imaging can play an important role in predicting and detecting tumor responses to treatment and thus in guiding treatment in individual patients [1]. Nuclear spin hyperpolarization can increase sensitivity in the magnetic resonance experiment by >10,000x. This has allowed imaging of injected hyperpolarized 13C labelled cell substrates in vivo and, more importantly, their metabolic conversion into other metabolites. We have been using this metabolic imaging technique both to detect treatment response and to investigate the tumor microenvironment. A recent perspective on this field of research is given in [2]. Exchange of hyperpolarized 13C label between lactate and pyruvate and net flux of label between glucose and lactate have been shown to decrease post-treatment and hyperpolarized [1,4-13C]fumarate has been shown to detect subsequent cell necrosis. Tumor pH can be imaged using hyperpolarized H13CO3- and redox state can be determined by monitoring the oxidation and reduction of [1-13C]ascorbate and [1-13C]dehydroascorbate respectively. In this talk I will discuss more recent work in which we have used hyperpolarized [1-13C]pyruvate to investigate metabolism in PDX models of glioblastoma. These measurements have shown significant heterogeneity between tumors derived from different patients, which we believe is related to underlying oncogenic mutations. I will also show how hyperpolarized [1-13C]pyruvate can be used to follow the progression of pancreatic precursor lesions, in a genetically engineered mouse model of the disease, which potentially could be used clinically to guide earlier intervention [3]. Finally I will discuss how we have used hyperpolarized [U-2H, U-13C]glucose [4] to investigate flux in the pentose phosphate pathway (PPP) and the relationship between PPP flux and the rate of reduction of hyperpolarized [1-13C]dehydroascorbate.

Metabolic imaging with hyperpolarized 13C-labelled cell substrates has recently translated to the clinic with a study in prostate cancer [5] and we have conducted our first clinical study in Cambridge using this technique earlier this year.

1. Brindle, K. Nature Rev Cancer 8, 94-107 (2008).

2. Brindle, K.M. J. Amer. Chem. Soc. 137, 6418-6427 (2015).

3. Serrao, E.M., et al. Gut 65, 465-475 (2016).

4. Rodrigues, T.B., et al. Nat Med 20, 93-97 (2014).

5. Nelson, S.J., et al. Science Translational Medicine 5, 198ra108 (2013).

Citation Format: Kevin M. Brindle. Imaging tumor metabolism with hyperpolarized 13C-labeled cell substrates. [abstract]. In: Proceedings of the AACR Special Conference on Engineering and Physical Sciences in Oncology; 2016 Jun 25-28; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2017;77(2 Suppl):Abstract nr IA14.
Abstract IA22: Non-coding RNA from discovery to therapy
Authors: Sharp Phillip
Published: March 2017

The central roles of non-coding RNAs in both normal and malignant cells offer new approaches to detection and treatment of cancer. Changes in microRNA levels have illuminated epigenetic processes that appear to maintain an embryonic malignant state in some adult cancer cells. This epigenetic network involves a small set of oncofetal genes, also expressed in early embryos, conferring malignant properties. This same set is also part of a larger network that integrates nutrient level data according to the size of the vertebrates where it is found. Further, the existence of the biosynthetic pathway for microRNAs in all adult cells allows introduction of small interfering RNAs to silence genes. This is now highly effective for silencing genes in the liver of patients and may become a general new therapeutic modality. Finally, many long non-coding RNAs are synthetized from promoters and enhancers by divergent transcription. The importance of these non-coding RNAs in regulation of nearby genes is being investigated but there is no question that enhancers stimulate promoters through processes involving the action of RNA polymerase. It is critical to understand the mechanism of enhancer action because many new drug agents preferentially target super-enhancer associated genes. This type of enhancer is frequently associated with oncogenes in cancer cells.

Citation Format: Phillip Sharp. Non-coding RNA from discovery to therapy. [abstract]. In: Proceedings of the AACR Special Conference on Engineering and Physical Sciences in Oncology; 2016 Jun 25-28; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2017;77(2 Suppl):Abstract nr IA22.
Abstract PR05: Glycoprotein-mediated tissue mechanics regulate glioblastoma aggression
Authors: Barnes J. Matthew , Woods Elliot C. , Bainer Russell O. , Miroshnikova Yekaterina A. , Lu Kan , Bergers Gabriele , Bertozzi Carolyn , Weaver Valerie M.
Published: March 2017

Glioblastoma multiforme (GBM) is a malignant glioma whose progression is associated with rampant extracellular matrix (ECM) remodeling. We recently found that GBM ECM stiffness predicts reduced survival in human patients. Instead of collagen fibrosis, which is common in many solid tumors, we showed that GBM stiffening involves increased production of extracellular glycoproteins, glycosaminoglycans, and sugar-binding proteins. Using bioinformatics, we revealed that genes of the glycocalyx (transmembrane glycoproteins and their interacting partners) are disproportionately upregulated in GBM relative to lower grade gliomas. Further, these genes are overexpressed within GBM in the mesenchymal (MES) relative to the proneural (PRO) subtype, the former of which is associated with treatment resistance and relapse. Using mouse models of human GBM, we showed that MES tumors are more lethal than PRO, and present with elevated ECM stiffness and mechanical signaling. To test our hypothesis that mechanical signaling can drive the MES phenotype, we engineered PRO GBM cells with constitutively-elevated integrin signaling. Compared to control PRO cells, these undergo a robust MES-like transition, upregulate bulky glycoprotein expression, and result in stiffer and more lethal tumors. This phenotype was reversed by the inhibition of focal adhesion kinase in MES cells. To test whether an enhanced glycocalyx can directly elevate mechanical signaling, we decorated GBM cells with synthetic glycoprotein polymers. Indeed, this resulted in enhanced integrin-focal adhesion signaling and more aggressive tumor progression. The invasive properties and therapy resistance observed in mesenchymal tumor cells are often associated with elevated stem cell-like features. To investigate a link between the glycocalyx, tissue mechanics, and the mesenchymal-stem cell phenotype, we interfered with components of the gylcocalyx or mechanical signaling machinery and found a reduction in stem cell genes and surface proteins, as well as increased sensitivity to chemotherapy. These data support a model in which glycoprotein-mediated tissue stiffening drives GBM aggression through promotion of a mesenchymal phenotype.

This abstract is also being presented as Poster A39.

Citation Format: J. Matthew Barnes, Elliot C. Woods, Russell O. Bainer, Yekaterina A. Miroshnikova, Kan Lu, Gabriele Bergers, Carolyn Bertozzi, Valerie M. Weaver. Glycoprotein-mediated tissue mechanics regulate glioblastoma aggression. [abstract]. In: Proceedings of the AACR Special Conference on Engineering and Physical Sciences in Oncology; 2016 Jun 25-28; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2017;77(2 Suppl):Abstract nr PR05.