Event
James Shamul - PhD Dissertation
Tuesday, April 2, 2024
3:30 p.m.
AJC 5104 (5th floor conference room)
Rachel Chang
301-405-8268
rachel53@umd.edu
Title: Multiscale Biomaterials-Enabled Glioblastoma Stem Cell-Targeted Therapy with microRNA to Overcome Cancer Recurrence
Committee members:
Dr. Xiaoming He, Chair
Dr. Shuo Gu
Dr. Alfredo Quiñones-Hinojosa
Dr. Helim Aranda-Espinoza
Dr. Shaik O. Rahaman, Dean’s Representative
Abstract:
Glioblastoma (GBM) is one of the most lethal diseases in the world with a dismal ~7.2% 5-year survival rate and median survival time of ~15 months. More than 90% of GBM patients experience recurrence. This recurrence is primarily attributed to the presence of a rare population of cancer cells inside tumors called cancer stem cells (CSCs). These CSCs are highly drug-resistant and tumorigenic due to their ability to self-renew from only one, single cell. To address recurrence in GBM, it is crucial to isolate true glioblastoma stem cells (GSCs), which possess two main abilities of all classical stem cells: self-renewal and multilineage differentiation. Current isolation technologies for GSCs, and all CSCs, predominantly include 1) sorting based on the expression of putative markers for CSCs, and 2) 3D neurosphere suspension culture in defined, serum-free medium. However, these methods are unreliable because there is no definitive marker for CSCs and there is merging of cells in suspension culture, which makes it difficult to isolate all CSCs with high purity. As a result, no GSCs have been previously isolated that include the capabilities of both self-renewal and multi-lineage differentiation. By adapting the microfluidic-enabled 1-cell culture method that we recently developed for isolating breast CSCs, we isolated patient GSCs that are capable of self-renewal and multi-lineage differentiation. This has never been shown before. With microRNA (miR) sequencing, we identified novel miRs that are differentially expressed in the GSCs from our 1-cell culture compared to “GSCs” from conventional suspension culture. These miRs were encapsulated inside nanoparticles for efficient and specific delivery into the cytosol where they perform the RNA interference function. These nanoparticles generate gas and disassemble under low pH conditions, and are thus named “nanobombs” due to this explosive effect. The nanobombs demonstrate efficient blood-brain barrier (BBB) crossing in vitro and endosomal escape into the cytosol of GBM cells. After treatment with miR-laden nanobombs, GBM cells show diminished stemness expression and self-renewal capability. Moreover, miR-laden nanobomb and temozolomide co-treatment inhibits recurrence in vitro. However, there is recurrence in GBM cells treated with non-combinatorial treatments and combinations that do not include target miR-laden nanobombs with temozolomide. Using a multi-scale approach that includes 1) microfluidics for fabricating 1-cell-laden, core-shell hydrogel microcapsules which eventually encapsulate GSC clones, 2) miR target identification in GSCs, and 3) nanobombs, which are gas-generating, BBB-penetrating and endosome-escaping, for encapsulating the miR target for delivery, there is promise to target true GSCs and inhibit recurrence, the major cause of GBM patient mortality.
