We are applying to establish a monoclonal antibody (mAb) and protein/tissue array facility that will allow us to accelerate the generation and characterization of mAbs generated against embryonic, normal adult tissue and tumor stem cells from a wide variety of tissues and developmental stages. MAbs are one of the most powerful tools we have for the study of stem cell biology. mAbs alone or more often in combination, can be used to isolate cell subsets, to identify cells in tissues in histological section as well as to therapeutically target specific cells. We have a long history of generating mAbs and using them to prospectively isolate and characterize stem and progenitor cells . Cancer stem cells are the cells within a tumor that are responsibly for initiating and maintaining the tumor. the generation of tools that recognize these cells specifically will facilitate the study of those cancers and the development of effective therapies to treat them. Tools that recognize tissue specific stem cells derived from embronic stem cells will facilitate the understanding of normal tissue and organ development and facilitate research that will lead to regenerative medicine therapies. There is a great need for additional tools such as these in stem cell research. By screening these mAb libraries against a wide variety of cells and tissue microarrays we can efficiently and cost effectively identify useful reagents that will help identify and quantify cancer stem cells and tissue derived or ESC derived stem cells in vivo and in vitro. The novel mAbs generated and characterized in this proposal, after filing for intellectual property protection, will be useful tools available to the entire CIRM community and can be further developed for research, diagnostic and therapeutic applications.
Statement of Benefit to California:
The principle objective of this proposal is to develop and screen antibodies, which, alone or more likely in combinations, can identify and isolate cancer stem cells, adult stem cells and tissue-regenerating stem cells derived from hESC lines. Antibodies are highly specific and powerful tools that can be used for research, diagnosis and therapeutic applications. We have also found that antibodies generated against stem cell antigens in one tissue often recognize the antigens present in other tissues as well. By screening the antibodies against dissociated cells as well as tissue microarrays of both normal and cancerous tissue we will be able to optimize the identification of useful clones. We have several libraries in development and propose to generate others. The antibodies and the cancer and other stem cells that they will allow to be identified and isolated from patients with specific diseases, will be invaluable tools that can be used to characterize their biology, to create model(s) for understanding the diseases and their progression, and to develop therapies.
In addition, the antibodies generated in these studies are entities that could be patented or protected by copyright, forming an intellectual property portfolio shared by the state and the state institutions wherein the research was carried out. The funds generated from the licensing of these technologies will help pay back the state, will help support increasing faculty and staff (many of whom bring in other, out of state funds for their research), and could be used to ameliorate the costs of clinical trials. Only California businesses are likely to be able to license these antibodies and cells, to develop them into diagnostic and therapeutic entities; such businesses are the heart of the CIRM strategy to enhance the California economy. The most important impact, however, is that this research will lead to cancer and tissue stem cell therapies. In the case of cancers, targeting the cancer stem cells specifically should be much more effective than nonspecific antiproliferative therapies that the cancer stem cells are often less sensitive to than the bulk of the tumor. In the case of tissue regenerating stem cells, such therapies will address chronic diseases that cause considerable disability and misery, currently have no cure, and therefore lead to huge medical expenses. Because tissue stem cells renew themselves for life, stem cell therapies are one-time therapies with curative intent. We expect that California hospitals and health care entities will be first in line for trials and therapies, and for CIRM to negotiate discounts on such therapies for California taxpayers, thus California will benefit both economically and with advanced novel medical care.
This application focuses on the establishment of monoclonal antibody (mAb) and protein/tissue array facilities to accelerate the pace of discovery and progress in stem cell biology. To achieve these objectives, the applicants propose to generate new antibodies to surface proteins from human embryonic stem cells (hESC) and their derivatives, from cancer stem cells and from normal tissue. The applicants will produce novel tissue arrays using samples from normal and tumor cells. The applicants propose to use these arrays, along with other existing arrays including arrays of known proteins, to screen and characterize the monoclonal antibodies and identify those that may be useful for the identification and isolation of several different types of stem cells. Finally, the resulting tools will be made available to members of the CIRM scientific community and the institution’s Regenerative Medicine program.
The reviewers were enthusiastic about the proposed potential for novel mAbs but were concerned that its overall impact would be lessened by not including the identification of unknown antibody targets within the project’s scope (except where antigen is present on protein array). The proposal was very diffuse and lacking in details, although the reviewers were confident in its underlying premise. A number of technical and conceptual deficiencies were noted, while several experiments were commended for their innovation. Finally, despite the outstanding research team and environment, it was not clear that the stated commitment of the investigators would be sufficient for this effort.
The impact that this technology would have on the field was considered to be high but somewhat limited. The proposed tools would undoubtedly be useful for pursuing anticipated paths of discovery and would potentially lead to advancements in the areas of basic research, diagnostics and therapeutics. However, some reviewers felt that limiting the scope of the effort to known antigens would prevent new, possibly groundbreaking avenues of investigation from being uncovered.
The reviewers found the proposal to be overly broad and lacking in details, but noted that the outstanding qualifications and experience of the research team spoke well to its merits. The research plan was straightforward and logical with modest and achievable milestones. Moreover, the applicants provided preliminary data that supported the rationale for the antibody approach and the applicant’s ability to execute. The reviewers cited as strengths the comprehensive screening and characterization experiments as well as the use of novel, targeted strategies for achieving the desired antibody populations. Beyond these strengths, several weaknesses were noted that diminished the overall enthusiasm of the reviewers. In general, the proposal seemed rather diffuse and lacked a central focus on any specific stem, progenitor, or cancer cell population. Concerns were also raised about the undefined purity of cell populations that are to be used as immunogens. One reviewer commented that the probability of identifying a rare stem cell marker from a heterogeneous pool would be remote. Furthermore, some reviewers expressed concerns about the limited throughput that could be achieved with these methodologies. The reviewers were also disappointed that only two cell lines were proposed for these studies. Finally, the applicants failed to provide a detailed discussion of the criteria that would be used to identify antibodies for follow up investigations.
The PI and co-investigators were described by the reviewers as eminently qualified, and experts in their respective fields. The only concern raised was that their commitment and the commitment of other project personnel might be insufficient given the ambitious scope of this effort and prior obligations of the PI and co-investigators to ongoing endeavors.
Overall, this was a promising proposal from an outstanding team, but the reviewers were uncertain of its potential to be successfully realized.