Glioblastoma (GBM) is the most common primary brain tumor in adults, and accounts for 20% of all primary brain tumors. GBM has a median survival rate of only 14.6 months despite current best treatment practices including surgery and chemoradiation. A significant reason for this morbidity and mortality is the ability of GBM to invade normal brain parenchyma, making localized treatment ineffective. There is increasing evidence of a small subset of cells, brain tumor initiating cells (BTICs) that are responsible for the disease's treatment resistance. In order for treatment to be effective, these invading cells need to be targeted. One promising approach involves the use of mesenchymal stem cells (MSCs), which have been found to migrate preferentially to and home in on cancer cells. Moreover, MSCs can be engineered to synthesize and release anti-tumor proteins, like bone morphogenic protein 4 (BMP4), which affects BTICs. MSCs can be obtained from bone marrow (BM- MSC) and adipose tissue (AMSCs). BM-MSCs are difficult to obtain, have limited ex vivo proliferation capacity, and decrease in effectiveness with donor age. Unlike BM-MSCs, AMSCs are more abundant in supply, easier to obtain from fat tissue, express higher levels of surface markers implicated in cell migration, and have been shown to resist oncogenic transformation. AMSCs may therefore be a better option. The viral gene delivery method, though commonly used to modify AMSCs, is associated with insertional mutagenesis and immunogenicity, and, therefore, has potentially limited translational ability for use in human patients. Biodegradable, polymeric nanoparticles enable effective non-viral gene delivery to multiple cell types, including human AMSCs (hAMSCs), while avoiding the problems typical of viruses. In this grant, we propose a novel technology to combine Freshly-extracted Adipose Tissue (F.A.T.) and nanoparticles to non-virally engineer the primary hAMSCs contained within F.A.T without prior culture to secrete anti-cancer proteins while maintaining the cells' ability to migrate toward tumo cells. Our overall hypothesis is that nanoparticle-modified hAMSCs obtained from F.A.T. retain their tumor suppressive characteristics in a clinically relevant in vivo human GBM model. To test this hypothesis, we will pursue the following specific aims: (1) To effectively deliver exogenous genes of interest to Freshly-extracted Adipose Tissue (F.A.T.) from patients via lyophilized biodegradable nanoparticles. (2) To determine if nanoparticle-modified BMP4-secreting hAMSCs retain an anti-glioma effect in vitro. (3) To determine the safety and efficacy of nanoparticle-modified BMP4-secreting hAMSC treatment in combination with targeted radiation therapy on human GBM in an in vivo murine model.
Aim 1 involves investigation and optimization of a unique technology of combining nanoparticles with F.A.T. from our patients.
For aims 2 and 3, using nanoparticles already tested in commercial hAMSCs, we will now investigate the modification of primary hAMSCs that have been isolated and cultured prior to adding the nanoparticles. The techniques to be used in vitro and in vivo in this proposal have been developed and further characterized by our teams. In vitro studies will be conducted using new advancements in the fields of microfluidics and nanobiotechnology. In vivo studies will employ a mammalian xenograft model that engrafts human GSC-derived GBM, which bests recapitulates human GBM. Further, in the in vivo studies, animal subjects will be treated with radiation using Small Animal Radiation Research Platform (SARRP), thus recreating traditional conformal beam radiotherapy for humans on the scale of a mouse. The results of this study will determine whether nanoparticle-modified hAMSCs can provide a treatment that is safe and effective for not only patients with GBM, but many types of primary and metastatic brain cancers. For future clinical application, the nanoparticles could be administered either to hAMSCs obtained from patient fat after culturing for a few days or then given IV as a treatment or to F.A.T. with the resulting engineered hAMSCs re- administered during surgery. This may lead to clinical trials, with a revolutionary new way of treating patients with brain cancer and facilitating personalized medicine.
Glioblastomas represent 54% of all gliomas and 17% of all primary brain tumors, according to the American Brain Tumor Association statistics. Moreover, metastatic brain tumors, most frequently from lung and breast cancers, are the most common type of brain tumor, with higher incidence than primary malignant brain tumors. The use of nanoparticles to engineer human adipose mesenchymal stem cells obtained from the fat tissue of our patients will lead to an effective translational technology for personalized medicine strategies to treat glioblastoma. Furthermore, these findings will likely lead to a new, more effective way to treat a currently incurable tumor that plagues many patients and families with the potential to translate into better treatments for other types of brain cancers including metastatic brain cancers.
