Publications by authors named "Derek Reichel"

Host-guest interactions represent a growing research area with recent work demonstrating the ability to chemically manipulate both host molecules as well as guest molecules to vary the type and strength of bonding. Much less is known about the interactions of the guest molecules and hybrid materials containing similar chemical features to typical macrocyclic hosts. This work uses in vitro and in vivo kinetic analyses to investigate the interaction of -dodecahydrododecaborate derivatives with ferumoxytol, an iron oxide nanoparticle with a carboxylated dextran coating.

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Successful visualization of prostate cancer (PCa) tumor margins during surgery remains a major challenge. The visualization of these tumors during surgery via near infrared fluorescence (NIRF) imaging would greatly enhance surgical resection, minimizing tumor recurrence and improving outcome. Furthermore, chemotherapy is typically administered to patients after surgery to treat any missed tumor tissue around the surgical area, minimizing metastasis and increasing patient survival.

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Background: There is a high incidence of posttraumatic osteoarthritis (PTOA) after anterior cruciate ligament (ACL) injury, and these injuries represent an enormous health care economic burden. In an effort to address this unmet clinical need, there has been increasing interest in cell-based therapies.

Purpose: To establish a translational large animal model of PTOA and demonstrate the feasibility of intra-articular human cell-based interventions.

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Article Synopsis
  • - Glioblastoma multiforme (GBM) is a highly aggressive cancer with limited treatment options due to its infiltrative nature and challenges in detecting tumors during surgery.
  • - Current treatments struggle with drug delivery, as most chemotherapeutic agents cannot effectively cross the blood-brain barrier (BBB) to reach GBM tumors.
  • - A new approach using HMC-FMX nanoparticles, which can visualize tumor boundaries and deliver drugs directly into GBM, shows promise in reducing tumor size and improving survival rates in preclinical models.
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A successful cancer surgery requires the complete removal of cancerous tissue, while also sparing as much healthy, non-cancerous tissue as possible. To achieve this, an accurate identification of tumor boundaries during surgery is critical, but intra-operative tumor visualization remains challenging. Fluorescence imaging is a promising method to improve tumor detection and delineate tumor boundaries during surgery, but the lack of stable, long-circulating, clinically-translatable fluorescent probes that can identify tumors with high signal-to-noise ratios and low background fluorescence signals have prevented its widespread application.

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Biological interactions between tumor-associated macrophages (TAMs), cancer cells and other cells within the tumor microenvironment contribute to tumorigenesis, tumor growth, metastasis and therapeutic resistance. TAMs can remodel the tumor microenvironment to reduce growth barriers such as the dense extracellular matrix and shift tumors towards an immunosuppressive microenvironment that protects cancer cells from targeted immune responses. Nanoparticles can interrupt these biological interactions within tumors by altering TAM phenotypes through a process called polarization.

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Cancer stem cells (CSCs) play pivotal roles in cancer metastasis, and strategies targeting cancer stemness may greatly reduce cancer metastasis and improve patients' survival. The canonical Wnt/β-catenin pathway plays critical roles in CSC generation and maintenance as well as in normal stem cells. Non-specifically suppressing the Wnt/β-catenin pathway for cancer therapy could be deleterious to normal cells.

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Colorectal cancer (CRC) is the second leading cause of cancer deaths in the United States; the predominant cause for mortality is metastasis to distant organs (e.g., lung).

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Purpose: To synthesize and assess the in vitro biological activity of nanoparticles containing leukemia inhibitory factor (LIF). These NanoLIF particles are designed to prolong the neuroprotective and anti-inflammatory actions of LIF in future preclinical studies of ischemic stroke.

Methods: LIF was packaged in nanoparticles made of poly(ethylene glycol)-poly(lactic acid) (PEG-PLA) polymer to form LIF-loaded nanoparticles (NanoLIF).

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Purpose: To develop polymer nanoassemblies (PNAs) modified with halofluorochromic dyes to allow for the detection of liver metastatic colorectal cancer (CRC) to improve therapeutic outcomes.

Methods: We combine experimental and computational approaches to evaluate macroscopic and microscopic PNA distributions in patient-derived xenograft primary and orthotropic liver metastatic CRC tumors. Halofluorochromic and non-halofluorochromic PNAs (hfPNAs and n-hfPNAs) were prepared from poly(ethylene glycol), fluorescent dyes (Nile blue, Alexa546, and IR820), and hydrophobic groups (palmitate), all of which were covalently tethered to a cationic polymer scaffold [poly(ethylene imine) or poly(lysine)] forming particles with an average diameter < 30 nm.

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Poly(ethylene glycol)-conjugated polyethylenimine (PEG-PEI) is a widely studied cationic polymer used to develop non-viral vectors for siRNA therapy of genetic disorders including cancer. Cell lines stably expressing luciferase reporter protein typically evaluate the transfection efficacy of siRNA/PEG-PEI complexes, however recent findings revealed that PEG-PEI can reduce luciferase expression independent of siRNA. This study elucidates a cause of the false positive effect in luciferase assays by using polymer nanoassemblies (PNAs) made from PEG, PEI, poly-(l-lysine) (PLL), palmitate (PAL), and deoxycholate (DOC): PEG-PEI (2P), PEG-PEI-PAL (3P), PEG-PLL (2P'), PEG-PLL-PAL (3P'), and PEG-PEI-DOC (2PD).

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Carfilzomib (CFZ) is a peptide epoxyketone proteasome inhibitor approved for the treatment of multiple myeloma (MM). Despite the remarkable efficacy of CFZ against MM, the clinical trials in patients with solid cancers yielded rather disappointing results with minimal clinical benefits. Rapid degradation of CFZ in vivo and its poor penetration to tumor sites are considered to be major factors limiting its efficacy against solid cancers.

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Purpose: To compare traditional dialysis- and novel solvatofluorochromism (SFC)-based methods for accurate determination of drug release profiles for nanoparticle drug carriers.

Methods: Polymer nanoassemblies (PNAs) varying in drug release patterns were prepared using poly(ethylene glycol), poly(ethylenimine), hydrophobic excipients (palmitate and deoxycholate), and model hydrophobic anticancer drugs with clinical relevance (carfilzomib and docetaxel). Nile blue (NB) was used as a model SFC dye quenching fluorescence in water yet emitting strong fluorescence in the presence of hydrophobic drugs within PNAs.

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Aim: Proteasome inhibitors, such as carfilzomib (CFZ), have shown potential to treat various types of cancers in preclinical models, but clinical applications are limited likely due to formulation and delivery issues. Results & methodology: Tethered polymer nanoassemblies (TNAs) were synthesized by tethering hydrophilic polymers and hydrophobic groups to charged polymer scaffolds, and then end-capping remaining amines on scaffold. Drug entrapment and drug release half-lives increased as charge was removed from scaffold.

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Background: Theranostics, an emerging technique that combines therapeutic and diagnostic modalities for various diseases, holds promise to detect cancer in early stages, eradicate metastatic tumors and ultimately reduce cancer mortality.

Methods & Results: This study reports unique polymer nanoassemblies that increase fluorescence intensity upon addition of hydrophobic drugs and either increase or decrease fluorescence intensity in acidic environments, depending on nanoparticle core environment properties. Extensive spectroscopic analyses were performed to determine optimal excitation and emission wavelengths, which enabled real time measurement of drugs releasing from the nanoassemblies and ex vivo imaging of acidic liver metastatic tumors from mice.

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Carfilzomib (CFZ) is a second-generation proteasome inhibitor drug approved for the treatment of multiple myeloma. Contrary to its excellent antimyeloma activity, CFZ has shown only limited efficacy in patients with solid malignancies. This lack of efficacy has been attributed in part to rapid degradation of CFZ in the body, possibly hindering the ability of CFZ to access the proteasome target in solid tumors.

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