Richard L. Klemke, Ph.D. - US grants

[unreadable] DESCRIPTION (provided by applicant): Mechanisms of cancer cell metastasis are poorly understood and there are currently are no reliable biomarkers or treatments available for this deadly disease. This is a particular problem in pancreatic and colon cancer, where most patients already display advanced metastatic disease at the time of diagnosis. Studying the metastatic process has proven difficult, because metastatic cells represent only a rare population of cells that reside in the tumor proper and established metastatic cell lines have undergone significant genetic drift over the years due to extended passaging in culture. This has severally hindered the application and interpretation of gene and protein profiling technologies. Thus, there is a crucial need to design more physiologically relevant systems to identify true, functionally important, molecular signatures of this disease. In this regards, important recent work has shown that it is possible to isolate rare metastatic cells from various organs in vivo. These cells when placed back into animals show significantly increased ability to metastasize a second time. Using this enrichment approach and gene profiling technology, a few important metastatic signatures (e.g. Twist, RhoC) have been identified and validated functionally. However, it has been estimated that only 40-60% of genetic changes observed at the mRNA level are actually reflected at the protein level making the functional relevance of most genetic profiles of metastatic cells questionable and the selection of candidate genes for validation problematic. Thus, there is a crucial need to identify functionally relevant protein signatures that predict metastatic disease. Such proteins would not only serve as true biomarkers of metastatic cancer, but also as novel therapeutic targets. To address this important need, we will use invivo selection to enrich for pancreatic cancer cells that spontaneously metastasize to lymph nodes of mice. We will utilize the Kras/lnk4a/Arf transgenic mouse model of pancreatic cancer which closely recapitulates the human form of metastatic cancer. The protein and phosphoprptein profiles of highly metastatic cells will then be determine using large-scale quantitative proteomics for comparison to control non-metastatic cells isolated from the primary tumor site. Proteins that signify metastatic cells will then be functionally validated using a gene knockout/knockin approach and animal models of cell metastasis. Finally, our published and preliminary data indicate that the src/CAS/Crk/PEAK signaling pathway is upregulated in highly metastatic cells selected in vivo. We will mechanistically determine how this signaling pathway facilitates metastasis and determine at what step in the metastastic process it impacts using high resolution imaging of metastasizing cells in live animals. Therefore our overall goal is to identify and functionally validate novel biomarkers of metastatic cells and determine how the src/CAS/Crk/PEAK pathway contributes to pancreatic cancer progression and metastasis in vivo. [unreadable] The overall goal of this work is to determine how cancer cells leave the primary tumor and spread throughout the body. Work on this proposal will identify new protein markers that will aide the clinician in the diagnosis of the spread of cancer and determine how molecular signals within the cell control this process. [unreadable] [unreadable] [unreadable]

adhesions; intermolecular interaction; cell migration; cell growth regulation; biomedical resource;

Animal Model; Animal Models and Related Studies; Antibodies; Assay; Bio-Informatics; Bioassay; Biochemical; Bioinformatics; Biologic Assays; Biological Assay; Biological Models; Brain; CCL26; CCL26 gene; CRISP; Cations; Cell Body; Cell Communication and Signaling; Cell Signaling; Cells; Chemoattractants; Chemotactic Factors; Chemotaxins; Complex; Computer Retrieval of Information on Scientific Projects Database; Computer Simulation; Computerized Models; Computers; Coupled; Degenerative Diseases, Nervous System; Degenerative Neurologic Disorders; Development; Digestion; Encephalon; Encephalons; Funding; Goals; Grant; Growth Cones; Human; Human, General; IMAC; Injury; Institution; Intracellular Communication and Signaling; Investigators; L-tyrosine, dihydrogen phosphate (ester); Laboratories; Location; MIP-4a; MIP-4alpha; Mammals, Mice; Man (Taxonomy); Man, Modern; Maps; Mathematical Model Simulation; Mathematical Models and Simulations; Methods; Mice; Model System; Models, Biologic; Models, Computer; Molecular; Murine; Mus; Mutagenesis, Site-Directed; Myelopathy, Traumatic; NCRR; NIH; National Center for Research Resources; National Institutes of Health; National Institutes of Health (U.S.); Nerve Cells; Nerve Degeneration; Nerve Unit; Nervous System, Brain; Neural Cell; Neurites; Neuroblastoma; Neuroblastoma (Schwannian Stroma-Poor); Neurocyte; Neurodegenerative Diseases; Neurodegenerative Disorders; Neurologic Degenerative Conditions; Neurologic Diseases, Degenerative; Neuron Degeneration; Neurons; Peptides; Phosphopeptides; Phosphoproteins; Phosphotyrosine; Process; Protein Analysis; Proteins; Proteomics; RNA, Small Interfering; Regulatory Protein; Research; Research Personnel; Research Resources; Researchers; Resolution; Resources; SCYA26; Sampling; Signal Transduction; Signal Transduction Systems; Signaling; Simulation, Computer based; Site; Site-Directed Mutagenesis; Site-Specific Mutagenesis; Small Interfering RNA; Source; Spinal Cord Trauma; Spinal Trauma; Spinal cord injured; Spinal cord injuries; Spinal cord injury; System; System, LOINC Axis 4; Targeted DNA Modification; Targeted Modification; Technology; Testing; Tyrosine Phosphorylation; Tyrosine Phosphorylation Site; Tyrosine-O-phosphate; United States National Institutes of Health; base; biological signal transduction; cell body (neuron); complement chemotactic factor; computational modeling; computational models; computational simulation; computer based models; computerized modeling; computerized simulation; experiment; experimental research; experimental study; gene product; genetic regulatory protein; imidazole-4-acetic acid; imidazolyl-4-acetic acid; in silico; model organism; neural cell body; neural degeneration; neurodegeneration; neurodegenerative illness; neuronal; neuronal cell body; neuronal degeneration; novel; regulatory gene product; research study; response; siRNA; soma; spinal cord regeneration; therapeutic target; virtual simulation

The overall goal of the Proteomics Initiative is to use mass spectrometry based proteomic[unreadable] methods to expand the current migration knowledge database by examining phosphorylation site utilization of[unreadable] proteins that regulate cell motility, by further developing methods for measuring differential phosphorylation of[unreadable] those proteins, and by using quantitative methods to assess positional and kinetic variation in phosphorylation[unreadable] site utilization in migration-related proteins. In addition, the Initiative will extend these proteomic methods to[unreadable] provide positional cartography of the proteins present in protein complexes formed by known migration-related[unreadable] proteins and protein products of novel migration genes identified in the unbiased screens of the Gene[unreadable] Discovery Initiative. These goals are enabled by several pivotal developments in technology, analysis, and[unreadable] methodology carried out during the first phase of funding. The Initiative focuses on two inter-related themes: 1.[unreadable] Phosphoproteomics of migration related proteins and 2. Positional proteomics of migration-related protein[unreadable] complexes and their phoshorylations.

[unreadable] DESCRIPTION (provided by applicant): Most of our mechanistic understanding of how human cancer cells migrate and invade has been obtained by observing cell behavior in an artificial 2 D environment. Although progress has been made using this approach, important new evidence indicates that cell migration in 2 D systems does not completely recapitulate events associated with locomotion in a more physiological environment using reconstituted 3 D matrices and tissue explants. Work by others and novel evidence provided in this research proposal demonstrate invasive cells can utilize either a mesenchymal type of cell invasion that involves formation of an elongated invadapodia and a spindle shaped morphology or a primitive amoeboid movement that involves membrane blebbing though small holes in the extracellular matrix. These breakthrough findings prompted the hypothesis that cells are armed with different invasive programs that allow them to traverse complex tissues and colonize foreign sites in the body. Most importantly though these findings indicate that therapeutic prevention of this process in patients will require a multifaceted approach that targets both modes of cell invasion. It is crucial then that we identify invasive mechanisms utilized by disseminating tumor cells in vivo so that the appropriate therapeutic agent(s) can be designed to completely eradicate the spread of cancer in patients. However, tumor cell invasion is a complex and dynamic process that involves the intricate interplay between the tumor cells and the remodeling vasculature and stroma. Understanding this process in vivo has been difficult because it has not been possible to visualize this process in high resolution in live animals. To address this problem, we have developed a novel model of cancer progression that utilizes human cancer cells growing in optical clear zebrafish genetically engineered to express green fluorescent protein in all blood vessels. Using this model and dual color high resolution confocal microscopy, we discovered that the metastatic gene RhoC induces a rapid cell invasion process that facilitates cell intravasation through vascular openings induced by VEGF secretion. In contrast, mesenchymal cell invasion involves formation of elongated invadopodia and membrane integration into the vascular wall, but not cell intravasation. Our goal in the proposed work is to understand the signaling mechanism that control amoeboid and mesenchymal invasion as cells intravasate and how the vascular pores form in response to VEGF secretion. Based on our preliminary findings and the work of others, we hypothesize that the metastatic gene RhoC mediates amoeboid invasion through Rho kinase activity (ROCK) and myosin II-mediated contractility. We also hypothesize that PI3K harboring activating mutations found in human cancers induces mesenchymal cell invasion through activation of the FAK-Src-CAS-Crk-Rac signaling module, which facilitates actin-mediated invadopodial protrusion. We hypothesize that the vascular pores form through disruption of cell-cell junctions, which is regulated by src phosphorylation of VE-cadherin. Therefore, our overall goal is to examine in detail how RhoC and mutated PI3K signaling pathways regulate cancer cell invasion and intravasation and the molecular signaling mechanisms that control vascular pore formation. PUBLIC HEALTH RELEVANCE: Cancer cells spread throughout the body by invading into blood vessels where they are carried to distant organs and form secondary tumors. Work in this proposal will determine the mechanism of how cancer cells invade through the vessel wall utilizing high resolution confocal imaging of optically transparent zebrafish harboring metastatic human cancer cells. [unreadable] [unreadable] [unreadable] [unreadable]

DESCRIPTION (provided by applicant): Directed cell migration, or chemotaxis, in response to a chemokine gradient is involved in development, immune function, inflammation, and cancer cell metastasis. However, little is known about the molecular signaling mechanisms that cause a stationary cell to become directionally motile and metastatic. Ultimately, these signals must target the actin-myosin cytoskeleton of the cell to induce an asymmetrical polarized morphology with a leading pseudopodium (invadapodium) and a rear compartment. Pseudopodia growth is associated with actin polymerization, membrane ruffling, and formation of new focal adhesions and occurs independently from cell body translocation. Establishment of the rear component occurs after pseudopodium formation and is characterized by loss of focal adhesions and strong actin-myosin contraction. Although it is clear that these events are important for cell movement, it has been technically difficult to study the spatial signals that direct the front and rear compartments of polarized cells using large-scale biochemical methods. To address this limitation, our laboratory developed a novel method for the purification of the pseudopodia and rear compartments of cells polarized towards a chemoattractant gradient. Using this novel purification method and phosphotyrosine affinity purification combined with LC-MS/MS protein identification, we discovered a new tyrosine kinase (KIAA2002) which is necessary for cell spreading, pseudopodia formation and proper cell migration. The KIAA2002 protein is highly enriched in the pseudopodium and localizes to the tips of pseudopodial extensions, where it associates with actin-rich membrane ruffles. Integrin-mediated cell adhesion and exposure to cells to growth factors and chemoattractants (LPA, EGF) facilitate tyrosine phosphorylation of KIAA2002. Based on our preliminary data and informatics, KIAA2002 is predicated to be phosphorylated by src kinase and to be a member of the canonical integrin signaling pathway Src/CAS/Crk/DOCK180/Rac-actin. Interestingly, this protein is also amplified in highly metastatic cancer cells including 70% of colon cancer patients with metastatic disease. Structure-function studies outlined in aim 1 will determine the mechanism(s) of how KIAA2002 couples to the migration machinery. In aim 2 we will determine the role of KIAA2002 in mediating human cancer cell metastasis in vivo. PUBLIC HEALTH RELEVANCE: In this proposal, we will determine how the novel tyrosine kinase KIAA2002 mediates pseudopodia formation and cell migration. We will also determine whether KIAA2002 contributes to cancer progression by regulating cell invasion and metastasis.

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The overall goal of this project is to understand the molecular signaling mechanisms that control tumor cell migration, invasion, and metastasis to distinct sites in the body. Cell metastasis is the major cause of disease relapse and decreased patient survival. We have developed a unique biochemical method to purify he very leading front (lamellipodia) of migrating cells(2). This breakthrough technology allows us to identify the key regulatory proteins that facilitate lamellipodia formation which is responsible for mediating cell invasion and metastasis. We will use monkey kidney epithelial cells (COS-7) and metastatic human breast adenocarcinoma cells (commercially available) for these studies. Initial analysis of purified lamellipodia from these cells has revealed that phosphotyrosine (PY) proteins are highly activated in the leading lamellipodia. Pharmacological inhibition of tyrosine phosphorylation inhibits lamellipodia formation indicating that complex signaling cascades operate to control this process through modulation of tyrosine networks. Therefore, our major objective is to characterize the PY proteins (lamellipodia phosphoproteome) responsible for lamellipodia formation and cancer cell metastasis using immunoaffinity purification with anti-phosphotyrosine antibodies followed by proteome analysis to identify proteins of interest. Results from our study will provide valuable information on the signals that control cell migration and metastasis, and provide targets for therapeutic intervention of cancer progression. Our specific aims are: Specific Aim 1. To identify PY proteins and their specific sites of tyrosine phosphorylation in the leading front of migrating cells. Specific Aim 2. To functionally test identified PY proteins using siRNA protein knockdown and site directed mutagenesis of key phosphotyrosine sites identified by MS followed by cell-based assays and animal models of cell migration established in our laboratory. Specific Aim 3. To determine the temporal and spatial distribution of tyrosine-containing proteins, phosphorylated and non-phosphorylated, and their relative abundance in a time course investigation of dormant vs actively migrating cells applying a combination of pulsed stable isotopic labeling with subcellular fractionation of cell bodies and of enriched lamellipodia. Specific Aim 4. To map the putative signaling cascades and develop functional relationships among the PY proteins using bioinformatics and computer modeling systems.

DESCRIPTION (provided by applicant): Because metastatic pancreatic cancer cells can disseminate from the primary tumor during the earliest stages of cancer progression, long before (10 years) the patient becomes symptomatic, the majority of patients have advanced stage metastatic disease at the time of diagnosis. This and the fact that patients resist all forms of conventional chemotherapy, pancreatic cancer has a dismal 5 year survival rate of less than 5%, and a median survival of 4-6 months. Clearly, to combat this devastating disease new biomarkers for early detection and new therapeutic targets directed at eliminating metastatic cells are urgently needed. Therefore, the objective of work in this proposal is to identify new proteins that mediate pancreatic ductal adenocarcinoma (PDAC), which can be used as biomarkers at and therapeutic targets to treat metastatic PDAC. To achieve this goal, in Aim 1 we will generate highly metastatic genetically engineered mouse and patient-derived PDAC cell lines by serial passaging of isolated metastatic cells in the pancreas of athymic nude mice. We will then biochemically purify their invadopodia, which drive PDAC cell invasion and metastasis, for proteomic and phosphoproteomic analyses. To identify metastatic signatures, the invasive invadopodia membranes will be interrogated for changes in total protein profile as well as kinase activation networks using established phosphosite identification methods, quantitative MudPIT mass spectrometry, and bioinformatics. In Aim 2, we will functionally test selected key signature proteins identified in Aim 1 for their ability to mediate PDAC cell metastasis using RNAi knockdown technology and preclinical animal models of PDAC cell metastasis. Our unique approach of using in vivo selected metastatic variants combined with invadopodia purification and comprehensive proteomics will reveal important new metastatic signature proteins that serve as 'fingerprints' to identify and treat metastatic PDAC cells. The identification of novel metastatic proteins is the first, and critical step, in the process that drives development of new PDAC therapeutics and diagnostics, which are sorely needed to treat this devastating disease.

DESCRIPTION (provided by applicant): Breast cancer cells commonly metastasize to the brain using mechanisms that are not fully understood. Because there are no effective therapeutics and surgical treatments are often problematic, the survival rate of breast cancer patients that develop brain metastases is dismal (<10 months). Recent work indicates that only metastatic breast cancer cells that attach to the vascular surface in the brain survive to form microtumors. Cells that invade deep into the brain parenchyma do not survive. These findings indicate the brain microvasculature provides a unique niche for breast cancer cell survival and propagation. However, it is not known how breast cancer cells attach to the vessel wall and communicate with the endothelium. Our recent published findings and preliminary results presented in this proposal demonstrate that Cx43-mediated gap junction (GJ) adhesion and communication with the brain vasculature is required for brain metastasis. Furthermore, we find that brain homing, metastatic cells, represent a subpopulation of tumor cells with stem cell-like properties (referred to as breast cancer stem cells, BCSCs). Importantly, BCSCs specifically express Cx43, which facilitates robust formation of Cx43-GJs with the Cx43-enriched brain vasculature. These findings are important because it provides a plausible explanation for why breast cancer cells commonly home to the brain and grow in association with the brain vasculature. Our findings also provide a unique mechanism to target metastatic cells in the brain with established GJ therapeutics such as carbenoxolone (CBX) and function blocking, cell-permeable peptides, which are currently being evaluated in clinical trials. Therefore, work i this proposal will determine precisely how heterocellular GJ communication and signal transduction regulates BCSC olonization of the brain vasculature. For these studies, we will use powerful fluorescent stem cell reporter constructs and specific gain or loss of function cx43 gene mutants in combination with unique preclinical animal models that facilitate intravital tracking and analysis of BCSC metastasis in the brain. Our work will provide a fundamental understanding of how BCSCs colonize the brain using GJ communication and determine if perturbation of this communication network can be used to treat metastatic disease in the brain.

There is a major need for new therapeutic strategies that target Kras in pancreatic ductal adenocarcinoma (PDAC) which has a dismal 5% survival rate. However, over 3 decades of work has failed to develop effective therapeutics against Kras or other mutant Ras isoforms (Hras, Nras), which account for approximately 30% of all human cancers. Recent published work in our laboratory revealed that mutationally activated Kras drives its own protein synthesis using a positive feedforward mechanism and the unique translation elongation factors eIF5A1. In fact, Kras drives increased eIF5A1 expression which in turns drives increased in Kras translation and downstream signaling, leading to increased cell proliferation and migration. More recently, we tested the ability of the highly related isoform eIF5A2 to regulate this pathway. Surprisingly, we discovered that eIF5A2 does not regulated Kras expression nor does it regulate PDAC cell growth, but rather it plays a unique role in regulating invadopodia formation and metastasis, which operates independent of eIF5A1. The identification that eIF5A2 mediates invadopodium formation and metastasis is an important breakthrough because it provides a new therapeutic strategy to target metastatic PDAC, which is sorely needed. In fact, unlike eIF5A1, which is ubiquitously expressed in tissues, eIF5A2 expression is restricted to brain and testis, but is selectively upregulated in malignant PDAC tissues and metastases making it an ideal biomarker and therapeutic target. Therefore, work outlined in this proposal will test the hypothesis that eIF5A2 regulates localized translation of mRNAs encoding key metastatic proteins that drive PDAC cell invasion and metastasis using the clinically relevant, immune competent, KCP mouse model of PDAC metastasis. The proposed work is important because the mechanisms that regulate mRNA translation in the invadopodium are poorly understood in general and have not been investigated in PDAC. A detailed understanding of this process could reveal new strategies and targets to modulate eIF5A2 protein expression, invadopodium formation, and PDAC metastasis. Such an approach is sorely needed for development of new and existing therapeutics to fight this deadly disease. Specific Aim 1. To determine the role of 5A2 in mediating 5A2, erbB2, PDGFR-b, and PEAK1 mRNA localization, translation, and signaling in invadopodium formation and cancer cell invasion. Specific Aim 2. To determine the role of 5A2 in mediating PDAC tumor formation and metastasis.

Among the 1.7 million new cases of breast cancer diagnosed globally each year, 15-20% are triple-negative breast cancer (TNBC), which has an aggressive phenotype with high metastatic capability and poor prognosis. However, current therapeutics for TNBC have unpredictable efficacy, poor biomarker availability, serious side effects, and the development of treatment resistance. The goal of this proposal is to develop our Cargocyte' technology (patents pending) to improve immune-oncology treatment in patients with TNBC by achieving the safe, non-toxic, targeted, and transient delivery of interleukin 12 (IL-12). IL-12 is a potent inflammatory cytokine and immune activator that attracted significant clinical interest because of its ability to induce a durable anti-tumor response in pre-clinical studies. However, initial clinical development was halted because systemic administration of IL-12 was associated with high levels of systemic toxicity, low response rates, and a narrow therapeutic window. Cargocytes possess unique advantages that facilitate delivery of IL-12 to the tumor microenvironment. They are transfected with IL-12 mRNAs that transform Cargocytes into cell-like factories producing high levels of secreted, bioactive, heterodimeric IL-12 cytokine (CA-IL-12). Compared with passive mechanisms of IL-12 delivery (purified IL-12 cytokine or mRNA, nanoparticles, exosomes etc.), Cargocytes deliver CA-IL-12 to the tumor microenvironment using multiple active cellular mechanisms that uniquely transform the tumor microenvironment from immunologically cold to hot. Furthermore, Cargocytes are tumor trophic and adhere to extracellular matrix (ECM) proteins within the tumor environment, which improves tumor retention and local CA-IL-12 delivery following IT administration. The proposed research in phase I will focus on (Aim 1) evaluating the ability of IT CA-IL-12 in combination with PD-1/PD-Ll immune checkpoint inhibition to target cancer progression using a stringent 4Tl murine orthotopic model of metastatic TNBC. Aim 2 will evaluate CA-IL-12/PD-Ll safety and toxicity in preparation for a type C pre-IND meeting using the 4Tl orthotopic model of metastatic TNBC. Following completion of these studies and guidance discussions with FDA regulatory personnel, further IND enabling work will be pursued by a phase II STTR proposal to develop CA-IL-12 for clinical applications.

There is critical need for therapeutic delivery devices that can be administered intravenously (IV), and effectively home to and deliver therapeutic agents to diseased tissues, while maintaining patient safety. Cytonus Therapeutics, in collaboration with UC San Diego's Moores Cancer Center, has pioneered a unique, drug transporter system with potential to treat to a wide range of cancers including advanced-stage metastatic tumors. Our novel platform for therapeutic delivery is to genetically engineer mesenchymal stem cells (MSCs) with specific tumor trophic proteins and then gently remove the nucleus, thereby providing a highly unique, viable, and safe drug delivery vehicle (CargocytesTM). Cargocytes are viable for at least 3-5 days and show dramatically reduced lung trapping after IV administration resulting in substantially improved homing to inflamed tissues in vivo. Moreover, Cargocytes can be engineered to express chemoattractant receptors CXCR4, CCR2, and the endothelial adhesion molecule PSGL-1, to enhance therapeutic delivery to tumors in response to their cognate ligands SDF-1, CCL2, and P-selectin, commonly upregulate in tumors and metastatic tissues, respectively. Therefore, feasibility studies will be performed to determine if cargocytes genetically engineered to simultaneously express chemoattractant receptors (CXCR4, CCR2) and PSGL-1 (endothelial adhesion molecule) facilitate improved homing to tumors (Aim 1) and lung metastases (Aim 2) in the MMTV-PyMT preclinical animal model of metastatic breast cancer. This work is important because bioengineered cargocytes could serve as a new biotransporter device to deliver therapeutics to malignant tumors and systemic metastases and maintain a clinically-relevant safety profile. Such innovative drug delivery platforms like Cargocytes are sorely needed to advance treatments for cancer patients with metastatic disease.

While the brain blood barrier (BBB) is an important physiological barrier that protects the brain, it is also represents a formable barrier to therapeutic delivery. Therefore, there is a critical need for therapeutic transporters that can be injected intravenously (i.v.), and effectively traverse the BBB and deliver therapeutic agents to the brain [1-8]. Cytonus Therapeutics has pioneered the development of a new bioinspired delivery agent (CargocytesTM) with potential to meet this critical need. Cargocytes are bioengineered enucleated mesenchymal stromal cells (MSCs) that specifically home to diseased tissues such as the brain and deliver therapeutic payloads following i.v. administration. Substantial work in our laboratory indicates that Cargocytes have potential to treat brain disorders as they readily extravasate through vascular barriers, invade endothelial basement membranes, and chemotax though complex extracellular matrices to target tissues deep within disease foci. Cargocytes can also be engineered to produce, secrete, and/or deliver a range of powerful therapeutics within the brain milieu including cytokines, neurotrophic factors, antibodies, nanobodies, RNAs, and even small molecule drugs. Overall, our findings demonstrate that Cargocytes are a new breakthrough technology platform for maximum local bioprotein delivery and production while minimizing systemic distribution. Cargocyte technology improves efficacy and reduces off-target toxicity, the ?holy grail? of therapeutic delivery. The primary objective of this phase I application is to develop brain homing Cargocytes that cross the BBB using an established model of ischemic brain injury.