Funding opportunities

Embryonic stem cell-derived neural stem cells for brain tumor and ALS therapy.

Funding Type: 
Comprehensive Grant
Grant Number: 
RC1-00358
Funds requested: 
$1 930 972
Funding Recommendations: 
Not recommended
Grant approved: 
No
Public Abstract: 
Glioblastoma is the most common and aggressive brain tumor. Despite surgery, radiation and chemotherapy, the median survival remains approximately 12 months. ALS is a neurodegenerative disease that attacks motor neurons and causes degeneration of nerves of the brain and spinal cord. The diagnosis of ALS leads to unrelenting progressive weakness leading to inability to breath. This project proposes fundamental scientific and clinical goals that are intimately tied: to understand the biology of neural stem cells (NSCs) derived from embryonic stem cells and to manipulate these functions for therapy. The limitation of current therapies for glioblastoma and ALS stems from their inablility to target infiltrating tumor cells and degenerating motor neurons within the spinal cord, respectively. However, the obstacles to effective therapy match the known biological properties of neural stem cells (NSCs). NSCs display a dramatic property of attraction towards areas of both tumors and neurodegeneration in the adult central nervous system. We have demonstrated the safety and usefulness fetal NSCs as delivery vehicles as a means of delivering agents to kill infiltrating brain tumor cells and have demonstrated a mechanism of how they are attracted to glioblastoma cells. We also described a rapid culture process whereby neural stem cells can be obtained from bone marrow cells. We have also demonstrated the ability of NSCs to prevent the progression of ALS in a mouse model of the human disease. We have demonstrated functional improvement and increased survival in SOD1 transgenic mice treated with intraspinal injections of fetal neural stem cells. These findings – taken together with the desperate state-of-affairs in glioblastoma and ALS therapy -- underscore the importance of research that might accelerate the translation of NSC-based adjuvant treatment strategies. This strategy has garnered attention, in part, because of the pioneering efforts and seminal reports from the investigators on this proposal who now hope to advance it rationally towards clinical translation. More recently, our collaborators have derived NSCs from pluripotent embryonic stem cells (ESCs), termed “ESC-derived NSCs” using a human feeder layer. Culturing without an animal feeder layer enables the clinical development of these cells. The use of NSCs derived from embryonic stem cells have the advantage of being well-characterized and readily available in limitless quantities for the earliest phases of a disease or insult. Starting from this point of departure, we will: AIM 1: Determine the attraction toward gliomas and areas of neurodegeneration of hNSCs derived from ESCs. AIM 2: Determine efficacy & safety of hNSCs derived from ESCs in targeting tumor-killing agents to human gliomas in mice. AIM 3: Determine efficacy & safety hESC-derived hNSCs in treating motor neuron degeneration in the SOD1 mouse model of ALS.
Statement of Benefit to California: 
This research will benefit California and its citizens by exploiting the powerful properties of embryonic stem cells to be made into brain and spinal cord cells to treat two very devastating neurologic disorders- glioblastoma (brain tumors) and ALS (Lou Gehrig's disease). This proposal addresses the principle aspiration of CIRM: 'to use stem cells to cure a variety of diseases.' Our goal and that of CIRM is to advance therapies to early stage clinical trials. This project will have an impact on five of the ten listed goals of CIRM's Scientific Strategic Plan: Goal I, CIRM grantees will have six therapies based on stem cell research in pre-clinical development -- We will advance two novel therapies for two devastating neurological disorders, glioblastoma and ALS. Goal II: CIRM grantees will have developed new methods of making stem cell lines- We are and will continue to develop efficient means of differentiating ESCs to neural progenitor cells. Goal VII, CIRM will have increased the workforce of stem cell researchers in California-We will recruit two full time trainees to work on this grant. Goal IX and X: CIRM will have established effective partnerships in stem cell research between scientific teams in non-profit and commercial centers and between national and international collaborations in stem cell research- This grant proposal forges a strong collaboration between a large clinical and preclinical entity with investigators that have a proven track record in preclinical development and clinical research and basic embryonic stem cell research with a superb basic stem cell research institute with an investigator that has made seminal contributions in the stem cell therapy field. The ESC lines that will be used were developed in xenogen-free medium with a human feeder layer in collaboration with a non-profit component of a large commercial leader in embryonic stem cell development with laboratories in {REDACTED}. The development of stem cell therapies for these devastating neurological disorders would make California the leading state for stem cell therapies, attracting both scientific talent and, in the future, investment for commercialization of these therapies.
Review Summary: 
SYNOPSIS: The studies proposed here will continue work begun by the PI to use NSCs as potential cell therapies for malignant glioma and ALS. hES cells will be studied for their ability to turn into NSCs that can track and deliver therapeutic molecules to glioma cells that have metastasized from a primary mass, and also differentiate into spinal cord cells that are at-risk in ALS. IMPACT AND SIGNIFICANCE: This PI proposes to utilize human embryonic stem cell (hESC)-derived neural stem cells (hNSC) in animal models to look at the migration of cells post-implantation to gliomas in rodents, and to determine if there are any effects in SOD1 mutant mice. This proposal focuses stem cells for two very challenging neurological disorders – glioma and ALS. Therefore, the potential impact and significance is extremely high. The idea of using NSC to seek out areas of tissue remodeling, including sites of motor neuron loss and sites of remote gliomagenic cells, is extremely significant. However, there are major questions as to whether this proposal will add significant information. QUALITY OF THE RESEARCH PLAN: The studies proposed here have the potential to increase our understanding of the cellular reagents for treating brain cancer and movement disorders. Three Specific Aims are proposed to: 1) determine whether ESC-derived hNSC will demonstrate tropism toward glioma and areas of neurodegeneration after transplantation; 2) determine whether human NSCs derived from ESCs are safe and effective in an experimental rodent glioma model; and, 3) determine whether human NSCs derived from ESCs transplanted into the spinal cords of SOD1[G93A] mice will alter pathophysiology by forestalling disease onset, slowing progression, preserving motor function, and prolonging life in these mice. The research proposal does not provide sufficient detail for the experiments or either disease model. The research plan does not address mechanisms, and the statistical analyses are not clear. For example, the investigator hopes to define the migration of cells (e.g., distance from injection) as well as differentiation of cells in the engraftment in animals with ALS/glioma; however, this is not clearly defined. STRENGHTS: This is an interesting problem. The PI’s recent work on generating NSCs for brain tumor and ALS studies has provided preliminary data and some proof of principle for the studies proposed here. For example, they have shown some functional improvement and longer survivals in SOD1 transgenic mice that were treated with cells derived from fetal NSCs. If it were possible to produce the “deliverable” of an hESC-derived “...NSC source that safely migrates to intracranial tumors and degenerating anterior horn motor neuron cells and continues to express a transgene in juxtaposition…” it would be important. The other goal to develop a method for “... deriving, maintaining, and differentiating hESCs under conditions that would be suitable for clinical use if grown under GMP...” would also be a strength if it could be accomplished. WEAKNESSES: In this proposal, which is rather poorly-written, there is insufficient justification for the experiments. The connection between glioma and ALS is slim at best, and both projects would require a huge effort to be able to generate the correct cellular reagents from ES cells, not to mention to be able to engineer them to release oncolytic or other molecular medicines to affect the survival or differentiation of “cancer stem cells”. To be able to generate bona fide motor neurons from ES cells has already been described by Zhang, Jessell, and others, and should therefore not be as challenging. Nonetheless, a huge number of experiments are proposed here that for the two disease models of choice would seem to each require their own dedicated series of studies. The deliverable of ESC-derived hNSC that are efficacious and safe for delivering enzyme or cytotoxic proteins to an intracranial tumor is noteworthy, but a major problem is the cells that have infiltrated the brain and left the tumor mass; the PI is well aware of this, and the challenge of course is getting NSCs to hunt out these discrete cells and deliver factors to these most dangerous cells. The IL-12 and TRAIL pilot studies are encouraging for finding such “tumor satellites”, but refining this methodology to be near proof-of-principle is enough work for this entire team for many years to come. Finally, the U87 glioma “model” in nude mice is not an unreasonable “model” to use, but there are better rodent models of intracranial glioma now, including the transgenics introduced by Holland and others, and newer “lines” made up of some of the best examples of glioblastoma-initiating cells. DISCUSSION: This proposal is based on the finding that stem cells will track to tumor cells, and can repopulate the ventral horn with motor neurons. The PI wants to test whether hESC will also track, and if so, use them as a method for delivering drugs that can help the motor neurons affected in ALS. The question to be addressed is whether the hESC can be loaded with molecular medicines and delivered to the affected site. The PI will use TRAIL and cytosine deaminases as the molecular medicines. There is good reason to think that this would work, but someone has to test the idea. Unfortunately, this grant wanders all over, and there is only a limited discussion of the experimental methods and how the research will be performed. The PI suggests studying two diseases (ALS and cancer). Reviewers feel that there is no connection between brain cancer and ALS, and the PI should focus on just one of these two very daunting diseases since the over-ambitious nature of studying both detracts from their enthusiasm. Also, since no mechanism is being studied the work is purely empirical in simply putting the cells in and seeing if they migrate. Finally, there was some concern over the budget relative to the work proposed. If the applicant is only looking at migration then the study should last less than a year.
Conflicts: 

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