SMARCB1 regulates the hypoxic stress response in sickle cell trait

Renal medullary carcinoma (RMC) is an aggressive kidney cancer that almost exclusively develops in individuals with sickle cell trait (SCT) and is always characterized by loss of the tumor suppressor SMARCB1. Because renal ischemia induced by red blood cell sickling exacerbates chronic renal medullary hypoxia in vivo, we investigated whether the loss of SMARCB1 confers a survival advantage under the setting of SCT. Hypoxic stress, which naturally occurs within the renal medulla, is elevated under the setting of SCT. Our findings showed that hypoxia-induced SMARCB1 degradation protected renal cells from hypoxic stress. SMARCB1 wild-type renal tumors exhibited lower levels of SMARCB1 and more aggressive growth in mice harboring the SCT mutation in human hemoglobin A (HbA) than in control mice harboring wild-type human HbA. Consistent with established clinical observations, SMARCB1-null renal tumors were refractory to hypoxia-inducing therapeutic inhibition of angiogenesis. Further, reconstitution of SMARCB1 restored renal tumor sensitivity to hypoxic stress in vitro and in vivo. Together, our results demonstrate a physiological role for SMARCB1 degradation in response to hypoxic stress, connect the renal medullary hypoxia induced by SCT with an increased risk of SMARCB1-negative RMC, and shed light into the mechanisms mediating the resistance of SMARCB1-null renal tumors against angiogenesis inhibition therapies.

Ether phospholipids are required for mitochondrial reactive oxygen species homeostasis

Mitochondria are hubs where bioenergetics, redox homeostasis, and anabolic metabolism pathways integrate through a tightly coordinated flux of metabolites. The contributions of mitochondrial metabolism to tumor growth and therapy resistance are evident, but drugs targeting mitochondrial metabolism have repeatedly failed in the clinic. Our study in pancreatic ductal adenocarcinoma (PDAC) finds that cellular and mitochondrial lipid composition influence cancer cell sensitivity to pharmacological inhibition of electron transport chain complex I. Profiling of patient-derived PDAC models revealed that monounsaturated fatty acids (MUFAs) and MUFA-linked ether phospholipids play a critical role in maintaining ROS homeostasis. We show that ether phospholipids support mitochondrial supercomplex assembly and ROS production; accordingly, blocking de novo ether phospholipid biosynthesis sensitized PDAC cells to complex I inhibition by inducing mitochondrial ROS and lipid peroxidation. These data identify ether phospholipids as a regulator of mitochondrial redox control that contributes to the sensitivity of PDAC cells to complex I inhibition.

Abstract 5868: Uncovering key microenvironmental features for immunotherapy response at the subclonal level in pancreatic cancer

The lack of suitable experimental approaches to investigate and model functional heterogeneity in vivo has had a profound negative impact on our understanding of how heterogeneity affects the response to immunotherapy. To bridge this technological gap, we leverage a new platform that visualizes the spatial architecture of subclones and microenvironments. To study heterogeneous populations of cells and their clonal dynamics in vivo, we performed barcode lineage tracing with next-generation sequencing analysis. It allows a quantitative evaluation of the spatial distribution and temporal clonal dynamic in vivo with multiple pharmacological perturbations, such as immune checkpoint blockade (ICB). We found that treatment with a PD1 inhibitor, despite a limited effect on tumor volume, induced dramatic changes in tumor clonal architecture. Furthermore, we revealed that subclones from well-defined geographical domains in vivo share differential behavior upon immune checkpoint blockade (ICB). By visualizing 40 different markers with multiplexed staining technology, we further identified that the microenvironment also exhibits a high level of spatial heterogeneity. Therefore, we coupled spatial barcode sequencing with high-content imaging and revealed the differential microenvironment feature of sensitive and resistant clones. We will further explore the mechanisms of immune evasion at the subclonal level. Through isolation and deep characterization of clonal lineages endowed with a distinct ability to engage the immune response, we hope to identify new vulnerabilities to overcome resistance to ICB.

Citation Format: Er-Yen Yen, I-Lin Ho, Chieh-Yuan Li, Charles Dyke, Shan Jiang, Francesca Citron, Sergio Attanasio, Rutvi Shah, Ko-Chien Chen, Giulio Draetta, Andrea Viale. Uncovering key microenvironmental features for immunotherapy response at the subclonal level in pancreatic cancer. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 5868.

Suppression of alias and replica noises in phase holograms using fractal topologies

Two-dimensional fractal topologies featuring (scaling) self-similarity, dense set of Bragg (diffraction) peaks, and inherent rotation symmetry, which are not achievable with regular grid-matrix geometries, exhibit optical robustness against structural damage and noise immunity of optical transmission paths. In this work, we numerically and experimentally demonstrate phase holograms using fractal plane-divisions. By taking advantage of the symmetries of the fractal topology, we propose numerical algorithms to design the fractal holograms. This algorithm solves the inapplicability of the conventional iterative Fourier transform algorithm (IFTA) method and enables efficient optimizations of millions of adjustable parameters in the optical element. Experimental samples show that the alias and replica noises in the image plane of fractal holograms are clearly suppressed, facilitating applications for high-accuracy and compact requirements.

Abstract 1327: Epithelial memory of resolved inflammation cooperates with oncogenic KRAS to limit tissue damage while promoting pancreatic cancer

The association between tumors and inflammation is a long-established clinical observation. Although many studies demonstrated that the inflammatory microenvironment can promote tumor growth through the activation of survival and proliferation programs in cancer cells, the reason why inflammation, an evolutionarily conserved response to damage aimed at reestablishing tissue integrity upon injury, might be integral to tumorigenesis still remains unknown. Pancreatic ductal adenocarcinoma (PDAC), a tumor characterized by poor prognosis, represents a distinctive example of cooperation between inflammation and activated oncogenes. Frequently developed in a context of chronic pancreatitis, PDAC is always associated with an inflammatory microenvironment. As supported by a substantial body of evidence across a multitude of experimental models, when occurring in the context of pancreatitis, mutations of KRAS, the universal oncogenic driver of pancreatic cancer, lead to accelerated tumor development inducing the appearance of neoplastic precursor lesions, such as acinar-to-ductal metaplasia (ADM) and pancreatic intraepithelial neoplasia (PanIN), which can evolve into invasive tumors. Interestingly, preneoplastic pancreatic alterations, specifically ADM, have been previously identified in acute and chronic pancreatitis in the absence of oncogene activation. Investigating the effects of inflammation on normal pancreatic epithelial cells, we discovered that long after complete resolution a transient inflammatory event primes cells to cooperate with oncogenic KRAS. Indeed, upon recovery from a single acute inflammation, epithelial cells display an enduring adaptive response associated with sustained epigenetic and transcriptional reprogramming. Such adaptation facilitates the prompt reactivation of acinar-to-ductal metaplasia upon subsequent inflammatory events, representing a physiological mechanism for limiting tissue damage via rapid decrease of zymogen production. Because metaplastic lesions are mediated by the activation of MAPK signaling, we demonstrated that activating mutations of KRAS, maintaining an irreversible ADM, are protective against tissue damage in a contest of pancreatitis. Uncovering a new physiologic role of somatic oncogenic mutations in preserving tissue integrity during repeated damages, we propose that KRAS mutations represent a nearly universal event in pancreatic cancer because beneficial and under strong positive selection in the context of recurrent pancreatitis.

Citation Format: I-Lin Ho, Edoardo Del Poggetto, Chiara Balestrieri, Er-Yen Yen, Francesca Citron, Rutvi Shah, Shaojun Zhang, Shan Jiang, Wantong Yao, Haoqiang Ying, Giannicola Genovese, Timothy Heffernan, Anirban Maitra, Linghua Wang, Timothy Wang, Giulio Draetta, Alessandro Carugo, Gioacchino Natoli, Andrea Viale. Epithelial memory of resolved inflammation cooperates with oncogenic KRAS to limit tissue damage while promoting pancreatic cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 1327.

K-series approximation of vectorial optical fields for designing diffractive optical elements with subwavelength feature sizes

Diffractive optical elements (DOEs) are widely applied as compact solutions for desired light manipulations via wavefront shaping. Recent advanced chip applications further require their feature sizes to move down to the subwavelength, which inevitably brings forth vectorial effects of optical fields and makes the typical scalar-based theory invalid. However, simulating and optimizing their vectorial fields, which are associated with billions of adjustable parameters in the optical element, are difficult to do, because of the issues of numerical stability and the highly-demanding computational cost. To address this problem, this research proposes an applicable algorithm by means of a wave-vector (k) series approximation of vectorial optical fields. On the basis of the semi-analytical rigorous coupled wave analysis (RCWA), an adequate selection scheme on k-series enables computationally efficient yet still predictive calculations for DOEs. The performance estimations for exemplary designs by the finite difference time domain (FDTD) method show that the predicted intensity profiles by the proposed algorithm agree with the target by just a fractional error. Together with optimizing the geometrical degrees of freedom (e.g., DOE depth h) as compensation for errors from the truncation of k-series, the algorithm demonstrates its outperformance by one or two orders of magnitude in accuracy versus the scalar-based model, and demands only a reasonable computational resource.

Epithelial memory of inflammation limits tissue damage while promoting pancreatic tumorigenesis

Inflammation is a major risk factor for pancreatic ductal adenocarcinoma (PDAC). When occurring in the context of pancreatitis, KRAS mutations accelerate tumor development in mouse models. We report that long after its complete resolution, a transient inflammatory event primes pancreatic epithelial cells to subsequent transformation by oncogenic KRAS. Upon recovery from acute inflammation, pancreatic epithelial cells display an enduring adaptive response associated with sustained transcriptional and epigenetic reprogramming. Such adaptation enables the reactivation of acinar-to-ductal metaplasia (ADM) upon subsequent inflammatory events, thereby limiting tissue damage through a rapid decrease of zymogen production. We propose that because activating mutations of KRAS maintain an irreversible ADM, they may be beneficial and under strong positive selection in the context of recurrent pancreatitis.

ZNRF1 Mediates Epidermal Growth Factor Receptor Ubiquitination to Control Receptor Lysosomal Trafficking and Degradation

Activation of the epidermal growth factor receptor (EGFR) is crucial for development, tissue homeostasis, and immunity. Dysregulation of EGFR signaling is associated with numerous diseases. EGFR ubiquitination and endosomal trafficking are key events that regulate the termination of EGFR signaling, but their underlying mechanisms remain obscure. Here, we reveal that ZNRF1, an E3 ubiquitin ligase, controls ligand-induced EGFR signaling via mediating receptor ubiquitination. Deletion of ZNRF1 inhibits endosome-to-lysosome sorting of EGFR, resulting in delayed receptor degradation and prolonged downstream signaling. We further demonstrate that ZNRF1 and Casitas B-lineage lymphoma (CBL), another E3 ubiquitin ligase responsible for EGFR ubiquitination, mediate ubiquitination at distinct lysine residues on EGFR. Furthermore, loss of ZNRF1 results in increased susceptibility to herpes simplex virus 1 (HSV-1) infection due to enhanced EGFR-dependent viral entry. Our findings identify ZNRF1 as a novel regulator of EGFR signaling, which together with CBL controls ligand-induced EGFR ubiquitination and lysosomal trafficking.

Excitation transport in quasi-one-dimensional quantum devices: a multiscale approach with analytical time-dependent non-equilibrium Green's function

Under the wide-band limit approximation for electrodes, this research proposes analytical time-dependent non-equilibrium Green's function (TD-NEGF) formulae to investigate dynamical functionalities of quasi-one-dimensional quantum devices, especially for (microwave) photon-assisted transports. Together with a multiscale approach by lumped element model, we also study the effects of transiently-transferring charges to reflect the non-conservation of charges in open quantum systems, and implement numerical calculations in hetero-junction systems composed of functional quantum devices and electrode-contacts (to the environment). The results show that (i) the current calculation by the analytical algorithms, versus those by conventional numerical integrals, presents superior numerical stability on a large-time scale, (ii) the correction of charge transfer effects can better clarify non-physical transport issues, e.g. the blocking of AC signaling under the assumption of conventional constant hamiltonian, (iii) the current in the long-time limit validly converges to the steady value obtained by standard time-independent density functional calculations, and (iv) the occurrence of the photon-assisted transport is well-identified.

Abstract C12: Lipids signaling contributes to glucose-independent metabolic adaptation in pancreatic ductal adenocarcinoma

Increasing researches verify that mitochondrial oxidase phosphorylation (OXPHOS) plays remarkable roles in cancer initiation, development, and drug resistance. Our previous study identified that preclinic OXPHOS inhibitor IACS-010759 significantly suppressed cancer cell growth in brain cancer and acute myeloid leukemia (AML) in vivo and in vitro with very low compound concentration. In pancreatic ductal adenocarcinoma (PDAC), there were actually different responses to OXPHOS inhibition in glucose-independent conditions. Using patient-derived xenograft (PDX) model, we identified sensitive and resistant groups to IACS-010759, and there were dramatic metabolic changes to feed-back compound resistance. By metabolomics analysis, we found a novel lipids-signaling activation mechanism that is responsible for the adaptive metabolic resistance. Furthermore, combination of OXPHOS inhibitor and specific lipids pathway inhibitor showed significant cancer cell growth suppression in resistant PDAC types. Our findings uncovered a novel adaptive metabolism in drug resistance and provide new thoughts on therapy strategy in PDAC.

Citation Format: Ziheng Chen, Jintan Liu, I-Lin Ho, Johnathan Rose, Liang Yan, Wantong Yao, Andrea Viale, Alessandro Carugo, Haoqiang Ying, Giulio Draetta. Lipids signaling contributes to glucose-independent metabolic adaptation in pancreatic ductal adenocarcinoma [abstract]. In: Proceedings of the AACR Special Conference on Pancreatic Cancer: Advances in Science and Clinical Care; 2019 Sept 6-9; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2019;79(24 Suppl):Abstract nr C12.

Pooled library screening with multiplexed Cpf1 library

Capitalizing on the inherent multiplexing capability of AsCpf1, we developed a multiplexed, high-throughput screening strategy that minimizes library size without sacrificing gene targeting efficiency. We demonstrated that AsCpf1 can be used for functional genomics screenings and that an AsCpf1-based multiplexed library performs similarly as compared to currently available monocistronic CRISPR/Cas9 libraries, with only one vector required for each gene. We construct the smallest whole-genome CRISPR knock-out library, Mini-human, for the human genome (n = 17,032 constructs targeting 16,977 protein-coding genes), which performs favorably compared to conventional Cas9 libraries.

Abstract 2900: Dissection of clonal heterogeneity unmasks pre-existing chemoresistance and new metabolic vulnerabilities in pancreatic cancer

Adaptive drug-resistance mechanisms allow human tumors to evade treatment through selection and expansion of treatment-resistant clones. Modeling the functional heterogeneity of tumors can unmask critical contributions of distinct tumor cell sub-populations toward identifying rational drug combinations. Here, studying clonal evolution of tumor cells derived from human pancreatic tumors, we demonstrate that in vitro adherent cultures and in vivo tumors are maintained by a common set of long term self-renewing tumorigenic cells that can be used to establish clonal replica tumors (CRTs), large cohorts of animals bearing human tumors with identical clonal composition. Using CRTs to conduct quantitative assessments of clonal dynamics and adaptive responses to therapeutic challenge over time, we uncovered that the tumorigenic compartment of pancreatic tumors maintains a multitude of functionally heterogeneous subpopulations of cells with differential degrees of sensitivity to therapeutics. High-throughput isolation and deep characterization of unique clonal lineages showed genetic and transcriptomic diversity underlying the functionally diverse subpopulations, positioning the origins of tumor heterogeneity within the long-term self-renewing compartment. Molecular annotation of gemcitabine-naïve clonal lineages with distinct responses to treatment in the context of CRTs generated signatures that can predict the response to chemotherapy and exposed pre-existing functional mechanisms of clonal resistance, primarily associated to DNA damage tolerance and mitochondrial respiration (OXPHOS). Further transcriptomic and metabolic characterization of residual tumor cells in patient derived xenograft models as well as in patients after chemoradiation showed that resistant cells that contribute to tumor relapse are metabolically rewired to upregulate OXPHOS. Combining a novel inhibitor of oxidative phosphorylation (IACS-10759) developed at the MD Anderson Institute for Applied Cancer Science, and currently in phase I clinical trial in acute myeloid leukemia and solid tumors, with standard of care drugs drastically reduces tumor clonal complexity, underscoring the promise of inhibiting mitochondrial respiration as a new therapeutic strategy to prolong patient survival by eradicating resistant clones that survive chemoradiation. Our study, correlating genomic and transcriptomic traits with specific functional phenotypes, uncovered new mechanisms that underlie intra-tumor sub-clonal heterogeneity, influence treatment response to drugs and sustain tumor relapse.

Citation Format: Sahil Seth, Chieh-Yuan Li, Sara Loponte, I-Lin Ho, Denise Corti, Luigi Sapio, Edoardo Del Poggetto, Michael Peoples, Tatiana Karpinets, Frederick S. Robinson, Shan Jiang, Prasanta Dutta, Joseph Marszalek, Maria E. Di Francesco, Timothy P. Heffernan, Virginia Giuliani, Pratip K. Bhattacharya, Giannicola Genovese, Andrew Futreal, Giulio Draetta, Andrea Viale, Alessandro Carugo. Dissection of clonal heterogeneity unmasks pre-existing chemoresistance and new metabolic vulnerabilities in pancreatic cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2900.

Study of wide-spectrum and high-resolution diffraction optical elements by stacks of binary phase gratings

This work theoretically investigates wide-spectrum and high-resolution diffraction optical elements that are made of stacks of low-resolution binary phase gratings, whereby the two-dimensional grids in different grating layers are arranged with specified displacements. We remodel the common kinoform algorithm for this multi-scale architecture. Numerical computations show that, by increasing the number of stacking layers, the resolution of the far-field image can be improved and also that the optical elements are more insensitive to variations of incident wavelengths at the cost of part accuracy of the image reconstructions. Practical concern focuses on largely increasing the number of grating layers and efficiency of the optical designs in theory and on the manufacture of stacks of ultra-thin grating films.

Abstract 1177: Clonal dissection of pancreatic tumors unmasks functional and genomic heterogeneous long-term self-renewing compartments at the origin of treatment resistance

Intrinsic and adaptive drug-resistance mechanisms allow human tumors to evade treatment through the demonstrated expansion of treatment-resistant clones. Thus, tumors are complex, dynamic ecosystems wherein populations of cells harboring both founder clones and unique, subclonal mutations coexist and progressively evolve. Modeling this functional heterogeneity of tumors can uncover critical contributions of distinct tumor cell sub-populations toward identifying rational drug combinations. Here, studying clonal evolution of tumor cells derived from human pancreatic tumors, we demonstrate that in vitro adherent cultures and in vivo tumors are maintained by a common set of long-term self-renewing cells that can be used to establish Clonal Replica Tumors (CRTs), large cohorts of animals bearing human tumors with identical clonal composition. Using CRTs to conduct quantitative assessments of clonal dynamics and adaptive responses to therapeutic challenge across different animals over time, we uncovered that the long term self-renewing compartment of pancreatic cancer is represented by a multitude of functionally heterogeneous subpopulations of cells with differential degrees of sensitivity to therapeutics. Consistent with the stem cell hypothesis, although tumors respond to treatments and undergo a transient regression, their clonal complexity at the time of relapse is only partially compromised, implying that many tumorigenic cells survive the treatment and sustain tumor relapse. Moreover, our ability to track the same cell populations in different animals enabled us to demonstrate that the clonal composition of relapsed pancreatic tumors varied across the different drug treatment groups (gemcitabine, MEK1 inhibitor and dual PI3K/mTOR inhibitor), suggesting that the compartment of long-term self-renewing tumorigenic cells is highly functionally diverse in mediating drug resistance to different therapies. Notably, high-throughput isolation and deep characterization of unique clonal lineages isolated through CRTs demonstrated that individual self-renewing populations display a remarkable genetic and molecular heterogeneity that can account for the differential functional responses and adaptation to perturbations. So, our findings portend a model in which the genomic and functional heterogeneity within human tumors is maintained, propagated and recapitulated entirely by distinct pools of long-term self-renewing cells. This concept has important implications for the efficacy of pharmacological combinations, which has historically been ascribed to their synergistic effects to abrogate the emergence of resistance, may instead be linked to the ability of mechanistically unrelated drugs to delay relapse by targeting multiple populations of tumorigenic cells simultaneously.

Citation Format: Sahil Seth, Chieh-Yuan Li, I-Lin Ho, Denise Corti, Sara Loponte, Luigi Sapio, Edoardo Del Poggetto, Michael Peoples, Tatiana Karpinets, Giannicola Genovese, Andrew Futreal, Giulio Draetta, Alessandro Carugo, Andrea Viale. Clonal dissection of pancreatic tumors unmasks functional and genomic heterogeneous long-term self-renewing compartments at the origin of treatment resistance [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 1177.

Abstract 4953: Metabolic targeting of chemoresistance perturbs clonal complexity in pancreatic cancer

A major barrier to achieving durable remission and definitive cure in oncology patients is the emergence of tumor resistance, a common outcome of different disease types independent from the therapeutic approach undertaken. Patients with pancreatic ductal adenocarcinoma (PDAC) continue to have a poor prognosis despite concerted efforts to advance new drugs to the clinic. One reason for this, in PDAC and other tumors, is that tumors are constantly adapting and evolving in response to external perturbations. To better investigate tumor evolution in response to therapy we developed a new clonal tracking platform that enables the in vivo study of long term self-renewing compartments and the generation of cohorts of patient-derived xenografts in which tumors are virtually identical and maintained by the same clones (clonal replica tumors), representing a unique tool to address fundamental questions about clonal dynamics in response to pharmacological treatment. Using this novel approach we demonstrate that standard of care in pancreatic cancer, despite inducing tumor regression, has minimal effect on the clonal composition of tumors that eventually relapse. Transcriptomic and metabolic characterization of residual tumor cells in patient derived xenograft models as well as in patients after chemoradiation shows that resistant cells that contribute to tumor relapse are metabolically rewired to upregulate mitochondrial respiration (OXPHOS). Combining a novel inhibitor of oxidative phosphorylation (IACS-010759), developed at the MD Anderson Institute for Applied Cancer Science and currently in phase I clinical trial in relapsed/refractory acute myelogenous leukemia and advanced solid tumors, with standard of care drugs drastically reduces tumor clonal complexity, underscoring the promise of inhibiting mitochondrial respiration as a new therapeutic strategy to prolong patient survival by eradicating resistant clones that survive chemoradiation.

Citation Format: Sara Loponte, Denise Corti, Sahil Seth, Edoardo Del Poggetto, I-Lin Ho, Chieh-Yuan Li, Shan Jiang, Joseph R. Marszalek, Maria Emilia Di Francesco, Giannicola Genovese, Giulio Draetta, Alessandro Carugo, Andrea Viale. Metabolic targeting of chemoresistance perturbs clonal complexity in pancreatic cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 4953.

Abstract A15: Generation of clonal replica tumors to interrogate complexity of human cancer in vivo

Tumor evolution and adaptation, especially in response to therapy, are well-established concepts in clinical oncology and a major causes of treatment failure. The inability of current experimental models, including genetically engineered mouse models, to inform on the breadth of functional heterogeneity within human tumors has substantially limited our understanding of the evolution of tumor architecture under perturbations such as pharmacologic treatments with a profound negative impact on cancer drug discovery research, where drug efficacy continues to be measured in terms of tumor volume.

To address this technologic gap, we developed a new approach based on clonal tracking to model human tumors in vivo supporting the dissection of functional heterogeneity at the clonal level as well as the study of tumor evolution and clonal dynamics in response to external perturbations in real time. Lentivirus-based systems have been extensively used as a tool to investigate the clonal dynamics and tumor cell heterogeneities of solid tumors, but they have been limited by a lack of sensitivity and the impossibility of tracking identical clones in different animals. Using a revised strategy to barcode patient-derived pancreatic cancer cells coupled with deep-sequencing analysis, we created PDX cohorts harboring Clonal Replica Tumors (hereafter CRTs), in which all mice bear human tumors maintained by the same clones. Because they are maintained by thousands of common clones and are virtually identical, CRTs enable the evaluation of single- and combined-therapy approaches as well as mechanistic studies where the evolution and dynamics of single clones can be tracked with extremely high precision to monitor the contribution of even low-represented clones to tumor growth and relapse. Since functional heterogeneity in tumors can only be fully appreciated upon different perturbations, the availability of large cohorts of animals bearing clonally identical tumors makes CRTs a critical instrument to investigate tumor complexity in vivo. Further, another advancement supported by the CRT platform is the isolation and expansion of any clone of interest identified in vivo through bioinformatics analysis. High-throughput isolation and functional characterization of virtually every clonal population of cells within a CRT provides an invaluable tool to identify exploitable vulnerabilities of resistant clones.

In conclusion, CRTs represent an innovative approach to dissect the complexity of human tumors at an unprecedented level of resolution, enabling the investigation of mechanisms of tumor evolution and drug resistance. Understanding clonal dynamics, tumor composition, and adaptive mechanisms, and how these factors may influence treatment response, is essential to reach new horizons in cancer care.

Citation Format: Sahil Seth, Chieh-Yuan Li, Denise Corti, Sara Loponte, I-Lin Ho, Edoardo Del Poggetto, Michael Peoples, Christopher Bristow, Joseph Marszalek, Timothy Heffernan, Giannicola Genovese, Giulio Draetta, Alessandro Carugo, Andrea Viale. Generation of clonal replica tumors to interrogate complexity of human cancer in vivo [abstract]. In: Proceedings of the AACR Special Conference: Advances in Modeling Cancer in Mice: Technology, Biology, and Beyond; 2017 Sep 24-27; Orlando, Florida. Philadelphia (PA): AACR; Cancer Res 2018;78(10 Suppl):Abstract nr A15.

Small Artery Elastin Distribution and Architecture-Focus on Three Dimensional Organization

The distribution of ECM proteins within the walls of resistance vessels is complex both in variety of proteins and structural arrangement. In particular, elastin exists as discrete fibers varying in orientation across the adventitia and media as well as often resembling a sheet-like structure in the case of the IEL. Adding to the complexity is the tissue heterogeneity that exists in these structural arrangements. For example, small intracranial cerebral arteries lack adventitial elastin while similar sized arteries from skeletal muscle and intestinal mesentery exhibit a complex adventitial network of elastin fibers. With regard to the IEL, several vascular beds exhibit an elastin sheet with punctate holes/fenestrae while in others the IEL is discontinuous and fibrous in appearance. Importantly, these structural patterns likely sub-serve specific functional properties, including mechanosensing, control of external forces, mechanical properties of the vascular wall, cellular positioning, and communication between cells. Of further significance, these processes are altered in vascular disorders such as hypertension and diabetes mellitus where there is modification of ECM. This brief report focuses on the three-dimensional wall structure of small arteries and considers possible implications with regard to mechanosensing under physiological and pathophysiological conditions.

MLN4924 Synergistically Enhances Cisplatin-induced Cytotoxicity via JNK and Bcl-xL Pathways in Human Urothelial Carcinoma

Cisplatin-based chemotherapy is the primary treatment for metastatic bladder urothelial carcinoma. However, the response rate is only 40–65%. This study investigated the anti-tumor effect and underlying mechanisms of the combination of cisplatin and the NEDD8-activating enzyme inhibitor MLN4924 in human bladder urothelial carcinoma. The combination of cisplatin and MLN4924 exerted synergistic cytotoxicity on two high-grade bladder urothelial carcinoma cell lines, NTUB1 and T24 (combination index <1). MLN4924 also potentiated the cisplatin-induced apoptosis and activation of caspase-3 and -7, phospho-histone H2A.X and PARP. c-Jun N-terminal kinase (JNK) activation and a down-regulation of B-cell lymphoma-extra large (Bcl-xL) were also observed during cisplatin and MLN4924 treatment. Inhibition of JNK activation partially restored cell viability and Bcl-xL expression. Bcl-xL overexpression also rescued cell viability. MLN4924 significantly potentiated cisplatin-induced tumor suppression in urothelial carcinoma xenograft mice. In summary, MLN4924 synergistically enhanced the anti-tumor effect of cisplatin via an increase in DNA damage, JNK activation and down-regulation of Bcl-xL in urothelial carcinoma cells. These findings provide a new therapeutic strategy for the treatment of bladder cancer.

MLN4924, a Novel NEDD8-activating enzyme inhibitor, exhibits antitumor activity and enhances cisplatin-induced cytotoxicity in human cervical carcinoma: in vitro and in vivo study

MLN4924, an inhibitor of NEDD8 activating enzyme (NAE), has been reported to have activity against various malignancies. Here, we investigated the antitumor properties of MLN4924 and MLN4924 in combination with cisplatin on human cervical carcinoma (CC) in vitro and in vivo. Two human CC cell lines, ME-180 and HeLa, were used in this study. The cytotoxic effects of MLN4924 and/or cisplatin were measured by cell viability (MTT), proliferation (BrdU incorporation), apoptosis (flow cytometry with annexin V-FITC labeling), and the expression of cell apoptosis-related proteins (Western blotting). In vivo efficacy was determined in Nu/Nu nude mice with ME-180 and HeLa xenografts. The results showed that MLN4924 elicited viability inhibition, anti-proliferation and apoptosis in human CC cells, accompanied by activations of apoptosis-related molecules and Bid, Bcl-2 phosphorylation interruption, and interference with cell cycle regulators. Moreover, MLN4924 caused an endoplasmic reticulum stress response (caspase-4, ATF-4 and CHOP activations) and expression of other cellular stress molecules (JNK and c-Jun activations). Additionally, MLN4924 suppressed growth of CC xenografts in nude mice. Furthermore, we demonstrated that MLN4924 potentiated cisplatin-induced cytotoxicity in CC cells with activation of caspases. Consistently with this, MLN4924 significantly enhanced cisplatin-induced growth inhibition of CC xenografts. Together, these findings suggest that MLN4924 alone or in combination with cisplatin is of value in treating human CCs.

Abstract 2525: MLN4924 synergistically enhances cisplatin-induced cytotoxicity via JNK and Bcl-xL pathways in human urothelial carcinoma - In vitro and in vivo study

Introduction

Cisplatin-based chemotherapy is the main treatment for metastatic bladder urothelial carcinoma; however, the response rate is only approximately 40-65%. Many patients will encounter drug resistance to chemotherapy eventually. Therefore, combination therapies to enhance the efficacy of cisplatin and to overcome drug resistance are imperative for the treatment of urothelial carcinoma. The aim of this study was to investigate the antitumor effect and underlying mechanisms for the combination of cisplatin and MLN4924, a NEDD8-activating enzyme inhibitor, in human bladder urothelial carcinoma.

Materials & Methods

We used MTT assays and CalcuSyn software to calculate the combination index of cisplatin and MLN4924. The expression levels of DNA damage response regulators, apoptotic-related molecules, MAPK and Bcl-xL were revealed by western blot. c-Jun N-terminal kinase (JNK) inhibitor (SP600125) and overexpression of Bcl-xL were used to investigate the relationship between JNK and Bcl-xL. The in vitro findings were further confirmed in vivo via xenograft mouse model.

Results

The combination of cisplatin and MLN4924 exerted synergistic cytotoxicity on two high-grade bladder urothelial carcinoma cell lines, NTUB1 and T24 (combination index &lt;1). In addition, MLN4924 potentiated cisplatin-induced apoptosis and activation of caspase-3, 7, phospho-histone H2A.X and PARP. We also observed c-Jun N-terminal kinase (JNK) activation with down-regulation of Bcl-xL during cisplatin and MLN4924 treatment. The inhibition of JNK activation partially restored cell viability as well as the expression of B-cell lymphoma-extra large (Bcl-xL); moreover, the overexpression of Bcl-xL rescued cell viability. In the in vivo study, MLN4924 significantly potentiated cisplatin-induced tumor suppression in urothelial carcinoma xenograft mice.

Conclusion

In summary, MLN4924 synergistically enhanced the antitumor effect of cisplatin through increasing DNA damage, JNK activation and down-regulating Bcl-xL in urothelial carcinoma cells. These findings provide a new therapeutiuc strategy for bladder cancer.

Citation Format: I-Lin Ho, Kuan-Lin Kuo, Chien-Tso Chou, Chen-Hsun Hsu, Yeong-Shiau Pu, Ju-Ton Hsieh, Kuo-How Huang. MLN4924 synergistically enhances cisplatin-induced cytotoxicity via JNK and Bcl-xL pathways in human urothelial carcinoma - In vitro and in vivo study. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 2525. doi:10.1158/1538-7445.AM2015-2525

Abstract 3770: MLN4924, a neddylation inhibitor, abolishes chemoresistance of bladder cancer stem-like cells through suppression of stemness

Introduction:

Bladder urothelial carcinoma (UC) ranks fourth in incidence among cancers in men and eighth in women in the United States, however, the chemotherapy response rate is only about half. The cancer stem cells (CSCs), which are believed as the driving force of tumor progression, have related to chemoresistance. Here we present the finding of CSC-like cells from human UC cell line NTUB1, and investigate the effect of MLN4924, a neddylation inhibitor on conquering chemoresistance in human UC.

Materials & methods:

The CSC-like cells were enriched from its parental cell line NTUB1 by cisplatin selection consecutively for at least one year. The properties of CSC-like cells were demonstrated by colony formation assay, side population assay, and cell viability assay. The expression levels of specific stemness-related markers, EMT-related markers and cell death-related molecules were revealed by western blot. The ability of migration was analyzed by wound-healing assay and transwell assay. The MLN4924-induced apoptosis on CSC-like cells were determined by flow cytometry with annexin V and propidium iodide (PI) staining. Gene knockdown was performed with gene-specific siRNA. The in vitro findings were further confirmed in vivo via xenograft mouse model.

Results:

The CSC-like cells exhibited multiple drug resistance, highly expression level of stemness markers as well as EMT markers, and highly mobility. The treatment of MLN4924 repressed the expression of stemness markers and EMT markers and reduced cell mobility; meanwhile, it caused significant cell death in CSC-like cells. The knockdown of stemness markers diminished the drug resistance of CSC-like cells. And in the end, MLN4924 significantly inhibit tumor growth in xenograft models bladder cancer stem-like cells.

Conclusion:

Our data suggested that the drug resistance in UC may conferred by CSC-like cells via up-regulation of stemness markers, and the treatment of MLN4924 could abolish drug resistance through repression of stemness markers. This could provide a new remedy for bladder cancer treatment.

Citation Format: Kuan-Lin Kuo, I-Lin Ho, Yeong-Shiau Pu, Yu-Chieh Tsai, Tsung-Hsien Shih, Kuo-How Huang. MLN4924, a neddylation inhibitor, abolishes chemoresistance of bladder cancer stem-like cells through suppression of stemness. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 3770. doi:10.1158/1538-7445.AM2014-3770

Abstract 1028: Anti-angiogenic activity of MLN4924 suppresses the growth of urothelial carcinoma via enhancing vascular normalization

Introduction:

Cullin-RING ligases (CRLs), the cullin-scaffold RING-finger domain containing E3, needs Nedd8 modification, neddylation, for the complete E3 activity, which promote the ubiquitination of specific substrate's degradation and regulate numerous biological processes. MLN4924, a neddylation inhibitor, was repoted to interfere in the neddylation of cullins and subsequently inactivate CRLs, leading to cell cycle arrest and apoptosis of tumors. Thus, we hereby present the detailed mechanism regarding the anti-angiogenesis of MLN4924 on suppressing the growth of urothelial carcinoma (UC) via inducing vascular normalization.

Materials & methods:

Human umbilical vein endothelial cells (HUVECs) were used to investigate the anti-angiogenic functions of MLN4924 in vitro, including WST-1 assay for evaluating proliferation, Transwell with or without Matrigel-coating for testing invasion and migration, gelatin zymography for assaying the matrix metalloproteinase activity, propidium iodide (PI) staining for investigating cell cycle progression, PI and annexin V co-staining for exploring cell death, Matrigel tube formation for examining angiogenic activity, and Western blotting for checking protein levels in cell cycle, apoptosis, and angiogenesis-associated signaling pathways. Besides, Matrigel plug assay was used to studying angiogenesis in vivo, and UC xenograft model was applied to research the tumor growth and tumor vascularity.

Results:

Our results showed that MLN4924 suppressed HUVEC's proliferation, migration, invasion, MMP 2 activation, and angiogenic tube formation. MLN4924 decreased angiogenic receptor VEGFR 2 and Tie2 expressions and inhibited VEGFR 2, ERK1/2, STAT 1 and 3, and AKT phosphorylations. MLN4924 induced the G2/M cell cycle arrest, which increased p21 and p27 accumulations and p53 phosphorylation but diminished histone 3 phosphorylation. Additionally, MLN4924 enhanced PARP, caspase -3, and -7 cleavages, which caused apoptosis. Furthermore, MLN4924 inhibited VEGF-induced angiogenesis in Matrigel-plug assay and repressed UC growth. CD31 and α-SMA immuno-staining was used for revealing the tumor vascularity, which showed that the microvessel density had no significantly difference between MLN4924-treated tumors and control tumors. However, the higher maturation vasculatures were found in MLN4924-treated tumors than control tumors.

Conclusion:

Our data suggest that MLN4924 inhibits the angiogenic phenotype of endothelial cells for enhancing tumor vascular normalization, which alleviates the hypoxic stress for slowing tumor growth. In addition, due to MLN4924 resulting in vascular normalization, MLN4924 may be able to synergize with conventional chemotherapies for treating UC. Therefore, exploring the function of MLN4924 in angiogenesis may result in a new perspective on targeting tumors and angiogenesis-dependent diseases.

Note: This abstract was not presented at the meeting.

Citation Format: Kuo-How Huang, Yeong-Shiau Pu, Yu-Chieh Tsai, Kuan-Lin Kuo, I-Lin Ho, Ju-Ton Hsieh, Tsung-Hsien Shih. Anti-angiogenic activity of MLN4924 suppresses the growth of urothelial carcinoma via enhancing vascular normalization. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1028. doi:10.1158/1538-7445.AM2014-1028

Celecoxib-induced cytotoxic effect is potentiated by inhibition of autophagy in human urothelial carcinoma cells

Celecoxib, a cyclooxygenase-2 (COX-2) inhibitor, can elicit anti-tumor effects in various malignancies. Here, we sought to clarify the role of autophagy in celecoxib-induced cytotoxicity in human urothelial carcinoma (UC) cells. The results shows celecoxib induced cellular stress response such as endoplasmic reticulum (ER) stress, phosopho-SAPK/JNK, and phosopho-c-Jun as well as autophagosome formation in UC cells. Inhibition of autophagy by 3-methyladenine (3-MA), bafilomycin A1 or ATG7 knockdown potentiated celecoxib-induced apoptosis. Up-regulation of autophagy by rapamycin or GFP-LC3B-transfection alleviated celecoxib-induced cytotoxicity in UC cells. Taken together, the inhibition of autophagy enhances therapeutic efficacy of celecoxib in UC cells, suggesting a novel therapeutic strategy against UC.

2-methoxyestradiol induces mitotic arrest, apoptosis, and synergistic cytotoxicity with arsenic trioxide in human urothelial carcinoma cells

2-Methoxyestradiol (2-ME), an endogenous derivative of 17β-estradiol, has been reported to elicit antiproliferative responses in various tumors. In this study, we investigated the effects of 2-ME on cell viability, proliferation, cell cycle, and apoptosis in human urothelial carcinoma (UC) cell lines. We used two high-grade human bladder UC cell lines (NTUB1 and T24). After treatment with 2-ME, the cell viability and apoptosis were measured by MTT assay and flow cytometry (fluorescence-activated cell sorting), with annexin V-FITC staining and propidium iodide (PI) labeling. DNA fragmentation was analyzed by agarose gel electrophoresis. Flow cytometry with PI labeling was used for the cell cycle analyses. The protein levels of caspase activations, poly (ADP-ribose) polymerase (PARP) cleavage, phospho-histone H2A.X, phospho-Bad, and cell cycle regulatory molecules were measured by Western blot. The effects of the drug combinations were analyzed using the computer software, CalcuSyn. We demonstrated that 2-ME effectively induces dose-dependent cytotoxicity and apoptosis in human UC cells after 24 h exposure. DNA fragmentation, PARP cleavage, and caspase-3, 7, 8, 9 activations can be observed with 2-ME-induced apoptosis. The decreased phospho-Bad (Ser136 and Ser155) and mitotic arrest of the cell cycle in the process of apoptosis after 2-ME treatment was remarkable. In response to mitotic arrest, the mitotic forms of cdc25C, phospho-cdc2, cyclin B1, and phospho-histone H3 (Ser10) were activated. In combination with arsenic trioxide (As2O3), 2-ME elicited synergistic cytotoxicity (combination index <1) in UC cells. We concluded that 2-ME significantly induces apoptosis through decreased phospho-Bad and arrests bladder UC cells at the mitotic phase. The synergistic antitumor effect with As2O3 provides a novel implication in clinical treatment of UC.

Approximate scheme by the coupled-wave theory to efficiently analyze the influences of moiré phenomena in liquid-crystal devices

This work studies an approximate scheme by coupled-wave theory to analyze quickly the large-scale moiré phenomena as seen in common liquid-crystal devices. The moiré phenomena are considered to be caused by two periodic structures (with lattice vectors γ[combininb arrow](1) and γ[combininb arrow](2) and show an interference pattern spanning over a length γ(m)=|γ[combininb arrow](1)|·|γ[combininb arrow](2)|/|γ[combininb arrow](1)-γ[combininb arrow](2)| (with γ[combininb arrow](1)=/~γ[combininb arrow](2)). With the coupled-wave theory, the complete analysis of the moiré optics includes at least 2γ(m)/λ (λ: wavelength in vacuum) Fourier components and presents an ineffective computation. This work applies a cos(τ) type approximation for the openings of unpatterned liquid-crystal pixels, and considers the first-order coupling between the Fourier components of pixels and other (periodic) optical structures. We hence arrive at an effective evaluation, including 4τ|γ[combininb arrow](1)|/λ (or 4τ|γ[combininb arrow](2)|/λ) Fourier components, and are able to go back to a complete analysis when considering higher-order couplings at an appropriate τ integer value.

Magnetic field enhanced resonant tunneling in a silicon nanowire single-electron-transistor

We report fabrication, measurement and simulation of silicon single-electron-transistors made on silicon-on-insulator wafers. At T-2 K, these devices showed clear Coulomb blockade structures. An external perpendicular magnetic field was found to enhance the resonant tunneling peak and was used to predict the presence of two laterally coupled quantum dots in the narrow constriction between the source-drain electrodes. The proposed model and measured experimental data were consistently explained using numerical simulations.