Browsing by Author "Smiley, Shelby B."

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    Novel therapeutics and drug-delivery approaches in the modulation of glioblastoma stem cell resistance
    (T&F, 2022-04) Smiley, Shelby B.; Zarrinmayeh, Hamideh; Das, Sudip K.; Pollok , Karen E.; Vannier, Michael W.; Veronesi, Michael C.; Radiology and Imaging Sciences, School of Medicine
    Glioblastoma (GBM) is a deadly malignancy with a poor prognosis. An important factor contributing to GBM recurrence is high resistance of GBM cancer stem cells (GSCs). While temozolomide (TMZ), has been shown to consistently extend survival, GSCs grow resistant to TMZ through upregulation of DNA damage repair mechanisms and avoidance of apoptosis. Since a single-drug approach has failed to significantly alter prognosis in the past 15 years, unique approaches such as multidrug combination therapy together with distinctive targeted drug-delivery approaches against cancer stem cells are needed. In this review, a rationale for multidrug therapy using a targeted nanotechnology approach that preferentially target GSCs is proposed with discussion and examples of drugs, nanomedicine delivery systems, and targeting moieties.
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    Targetable Multi-Drug Nanoparticles for Treatment of Glioblastoma with Neuroimaging Assessment
    (2020-05) Smiley, Shelby B.; Lin, Chien-Chi; Veronesi, Michael; Agarwal, Mangilal
    Glioblastoma (GBM) is a deadly, malignant brain tumor with a poor long-term prognosis. The current median survival is approximately fifteen to seventeen months with the standard of care therapy which includes surgery, radiation, and chemotherapy. An important factor contributing to recurrence of GBM is high resistance of GBM cancer stem cells (CSCs), for which a systemically delivered single drug approach will be unlikely to produce a viable cure. Therefore, multi-drug therapies are needed. Currently, only temozolomide (TMZ), which is a DNA alkylator, affects overall survival in GBM patients. CSCs regenerate rapidly and over-express a methyl transferase which overrides the DNA-alkylating mechanism of TMZ, leading to drug resistance. Idasanutlin (RG7388, R05503781) is a potent, selective MDM2 antagonist that additively kills GBM CSCs when combined with TMZ. By harnessing the strengths of nanotechnology, therapy can be combined with diagnostics in a truly theranostic manner for enhancing personalized medicine against GBM. The goal of this thesis was to develop a multi-drug therapy using multi-functional nanoparticles (NPs) that preferentially target the GBM CSC subpopulation and provide in vivo preclinical imaging capability. Polymer-micellar NPs composed of poly(styrene-b-ethylene oxide) (PS-b-PEO) and poly(lactic-co-glycolic) acid (PLGA) were developed investigating both single and double emulsion fabrication techniques as well as combinations of TMZ and RG7388. The NPs were covalently bound to a 15 base-pair CD133 aptamer in order to target a specific epitope on the CD133 antigen expressed on the surface of GBM CSC subpopulation. For theranostic functionality, the NPs were also labelled with a positron emission tomography (PET) radiotracer, zirconium-89 (89Zr). The NPs maintained a small size of less than 100 nm, a relatively neutral charge and exhibited the ability to produce a cytotoxic effect on CSCs. There was a slight increase in killing with the aptamer-bound NPs compared to those without a targeting agent. This work has provided a potentially therapeutic option for GBM specific for CSC targeting and future in vivo biodistribution studies.