Targeting different cell surface receptors with nanoparticle (NP)-based platforms can result in d... more Targeting different cell surface receptors with nanoparticle (NP)-based platforms can result in differential particle binding properties that may impact their localization, bioavailability, and, ultimately, the therapeutic efficacy of an encapsulated payload. Conventional in vitro assays comparing the efficacy of targeted NPs often do not adequately control for these differences in particle-receptor binding, potentially confounding their therapeutic readouts and possibly even limiting their experimental value. In this work, we characterize the conditions under which NPs loaded with Bruton's Tyrosine Kinase (BTK) inhibitor differentially suppress primary B cell activation when targeting either CD19 (internalizing) or B220 (noninternalizing) surface receptors. Surface binding of fluorescently labeled CD19- and B220-targeted NPs was analyzed and quantitatively correlated with the number of bound particles at given treatment concentrations. Using this binding data, suppression of B cell activation was directly compared for differentially targeted (CD19 vs B220) NPs loaded with a BTK inhibitor at a range of particle drug loading concentrations. When NPs were loaded with lower amounts of drug, CD19-mediated internalization demonstrated increased inhibition of B cell proliferation compared with B220 NPs. However, these differences were mitigated when particles were loaded with higher concentrations of BTK inhibitor and B220-mediated "paracrine-like" delivery demonstrated superior suppression of cellular activation when cells were bound to lower overall numbers of NPs. Taken together, these results demonstrate that inhibition of B cell activation can be optimized for NPs targeting either internalizing or noninternalizing surface receptors and that particle internalization is likely not a requisite endpoint when designing particles for delivery of BTK inhibitor to B cells.
Nanomedicine: Nanotechnology, Biology and Medicine, 2021
Magnetic resonance is a key imaging tool for the detection of prostate cancer; however, better to... more Magnetic resonance is a key imaging tool for the detection of prostate cancer; however, better tools focusing on cancer specificity are required to distinguish benign from cancerous regions. We found higher expression of claudin-3 (CLDN-3) and-4 (CLDN-4) in higher grade than lower-grade human prostate cancer biopsies (n=174), leading to the design of functionalized nanoparticles (NPs) with a non-toxic truncated version of the natural ligand clostridium perfringens enterotoxin (C-CPE) that has a strong binding affinity to Cldn-3 and Cldn-4 receptors. We developed a first-of-its-type, C-CPE-NP-based MRI detection tool in a prostate tumor-bearing mouse model. NPs with an average diameter of 152.9±15.7nm (RS1) had a 2-fold enhancement of tumor specificity compared to larger (421.2±33.8nm) NPs (RS4). There was a 1.8-fold (p<0.01) and 1.6-fold (p<0.01) upregulation of the tumor-to-liver signal intensities of C-RS1 and C-RS4 (functionalized NPs) to controls, respectively. Also, tumor specificity was 3.1-fold higher (p<0.001) when comparing C-RS1 to C-RS4. This detection tool improved tumor localization of contrast-enhanced MRI, supporting potential clinical applicability.
Background: Patients with epithelial ovarian cancer have the best overall survival when maximal s... more Background: Patients with epithelial ovarian cancer have the best overall survival when maximal surgical effort is accomplished. While identification and removal of large metastases do not pose a challenge, micrometastases are impossible to distinguish intra-operatively and contribute to the high mortality. Our objective is to develop specific tumor-targeting optical enhancers that can aid surgeons in the performance of microscopic tumor debulking with the goal of minimizing microscopic residual disease. We hypothesize that we can utilize overexpressed αVβ3 integrins in the tumor-associated neovasculature. Specific targeting is achieved by encapsulating fluorescent probes in FDA-approved PLGA-based nanoparticle (NP) coated with the peptide sequence arginine-glycine-aspartate (RGD), which binds with high affinity to these integrins. Materials and methods: Ovarian cancer xenograft is established intra- peritoneally (i.p.) in nude mice using cancer cells that stably express mCherry flu...
Here we report on a "configuration-dependent" mechanism of action for IL-15:IL-15Rα (he... more Here we report on a "configuration-dependent" mechanism of action for IL-15:IL-15Rα (heterodimeric IL-15, or hetIL-15), where the manner by which IL-15:IL-15Rα molecules are presented to target cells significantly impacts its function as a vaccine adjuvant. While the cellular mechanism of IL-15 transpresentation via IL-15Rα and its importance for IL-15 function have been described, the full impact of IL-15:IL-15Rα configuration on responding cells is not yet known. We found that transpresenting IL-15:IL-15Rα in multivalent fashion on the surface of antigen-encapsulating nanoparticles enhanced the ability of NP-treated dendritic cells (DC) to stimulate antigen-specific CD8+ T cell responses. Localization of multivalent IL-15:IL-15Rα and encapsulated antigen to the same DC led to maximal T cell responses. Strikingly, DCs incubated with IL-15:IL-15Rα-coated nanoparticles displayed higher levels of functional IL-15 on the cell surface, implicating a mechanism for nanoparticle-...
Proceedings of the 48th Design Automation Conference, 2011
Abstract Semiconducting nanowires (NWs) have the potential to function as highly sensitive and se... more Abstract Semiconducting nanowires (NWs) have the potential to function as highly sensitive and selective sensors for label-free detection of minute concentrations of target molecules. We discuss here an approach to NW sensors using CMOS (complementary metal-oxide-...
Vaccines for many infectious diseases are poorly developed or simply unavailable. There are signi... more Vaccines for many infectious diseases are poorly developed or simply unavailable. There are significant technological and practical design issues that contribute to this problem; thus, a solution to the vaccine problem will require a systematic approach to test the multiple variables that are required to address each of the design challenges. Nanoparticle technology is an attractive methodology for optimizing vaccine development because design variables can be tested individually or in combination. The biology of individual components that constitute an effective vaccine is often well understood and may be integrated into particle design, affording optimal immune responses to specific pathogens. Here, we review technological variables and design parameters associated with creating modular nanoparticle vaccine systems that can be used as vectors to protect against disease. Variables, such as the material and size of the core matrix, surface modification for attaching targeting ligand...
Vaccines that activate humoral and cell-mediated immune responses are urgently needed for many in... more Vaccines that activate humoral and cell-mediated immune responses are urgently needed for many infectious agents, including the flaviviruses dengue and West Nile (WN) virus. Vaccine development would be greatly facilitated by a new approach, in which nanoscale modules (Ag, adjuvant, and carrier) are assembled into units that are optimized for stimulating immune responses to a specific pathogen. Toward that goal, we formulated biodegradable nanoparticles loaded with Ag and surface modified with the pathogen-associated molecular pattern CpG oligodeoxynucleotides. We chose to evaluate our construct using a recombinant envelope protein Ag from the WN virus and tested the efficiency of this system in eliciting humoral and cellular responses and providing protection against the live virus. Animals immunized with this system showed robust humoral responses polarized toward Th1 immune responses compared with predominately Th2-biased responses with the adjuvant aluminum hydroxide. Immunizati...
There is a real need to develop new therapeutic strategies for African trypanosomiasis infections... more There is a real need to develop new therapeutic strategies for African trypanosomiasis infections. In our study, we developed a new drug delivery system of diminazene (DMZ), a trypanocidal drug registered for veterinary use. This drug candidate presents a limited efficacy, a poor affinity for brain tissue and instability. The development of colloidal formulations based on a porous cationic nanoparticle with an oily core ((70)DGNP(+)), has potentially two advantages: stabilization of the drug and potential targeting of the parasite. We analyzed two processes of drug loading: in process (DMZ was added during the preparation of (70)DGNP(+) at 80 °C) and post-loading (DMZ was mixed with a (70)DGNP(+) solution at room temperature). Poor stability of the drug was observed using the in process technique. When using the post-loading technique over 80% drug entrapment efficiency was obtained at a ratio of DMZ:phospholipids (wt:wt) &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 5%. Moreover, DMZ loaded into (70)DGNP(+) was found to be protected against oxidation and was stable for at least six months at 4 °C. Finally, in vitro tests on T.b. brucei showed an increased efficacy of DMZ loaded in (70)DGNP(+).
Targeting different cell surface receptors with nanoparticle (NP)-based platforms can result in d... more Targeting different cell surface receptors with nanoparticle (NP)-based platforms can result in differential particle binding properties that may impact their localization, bioavailability, and, ultimately, the therapeutic efficacy of an encapsulated payload. Conventional in vitro assays comparing the efficacy of targeted NPs often do not adequately control for these differences in particle-receptor binding, potentially confounding their therapeutic readouts and possibly even limiting their experimental value. In this work, we characterize the conditions under which NPs loaded with Bruton's Tyrosine Kinase (BTK) inhibitor differentially suppress primary B cell activation when targeting either CD19 (internalizing) or B220 (noninternalizing) surface receptors. Surface binding of fluorescently labeled CD19- and B220-targeted NPs was analyzed and quantitatively correlated with the number of bound particles at given treatment concentrations. Using this binding data, suppression of B cell activation was directly compared for differentially targeted (CD19 vs B220) NPs loaded with a BTK inhibitor at a range of particle drug loading concentrations. When NPs were loaded with lower amounts of drug, CD19-mediated internalization demonstrated increased inhibition of B cell proliferation compared with B220 NPs. However, these differences were mitigated when particles were loaded with higher concentrations of BTK inhibitor and B220-mediated "paracrine-like" delivery demonstrated superior suppression of cellular activation when cells were bound to lower overall numbers of NPs. Taken together, these results demonstrate that inhibition of B cell activation can be optimized for NPs targeting either internalizing or noninternalizing surface receptors and that particle internalization is likely not a requisite endpoint when designing particles for delivery of BTK inhibitor to B cells.
Nanomedicine: Nanotechnology, Biology and Medicine, 2021
Magnetic resonance is a key imaging tool for the detection of prostate cancer; however, better to... more Magnetic resonance is a key imaging tool for the detection of prostate cancer; however, better tools focusing on cancer specificity are required to distinguish benign from cancerous regions. We found higher expression of claudin-3 (CLDN-3) and-4 (CLDN-4) in higher grade than lower-grade human prostate cancer biopsies (n=174), leading to the design of functionalized nanoparticles (NPs) with a non-toxic truncated version of the natural ligand clostridium perfringens enterotoxin (C-CPE) that has a strong binding affinity to Cldn-3 and Cldn-4 receptors. We developed a first-of-its-type, C-CPE-NP-based MRI detection tool in a prostate tumor-bearing mouse model. NPs with an average diameter of 152.9±15.7nm (RS1) had a 2-fold enhancement of tumor specificity compared to larger (421.2±33.8nm) NPs (RS4). There was a 1.8-fold (p<0.01) and 1.6-fold (p<0.01) upregulation of the tumor-to-liver signal intensities of C-RS1 and C-RS4 (functionalized NPs) to controls, respectively. Also, tumor specificity was 3.1-fold higher (p<0.001) when comparing C-RS1 to C-RS4. This detection tool improved tumor localization of contrast-enhanced MRI, supporting potential clinical applicability.
Background: Patients with epithelial ovarian cancer have the best overall survival when maximal s... more Background: Patients with epithelial ovarian cancer have the best overall survival when maximal surgical effort is accomplished. While identification and removal of large metastases do not pose a challenge, micrometastases are impossible to distinguish intra-operatively and contribute to the high mortality. Our objective is to develop specific tumor-targeting optical enhancers that can aid surgeons in the performance of microscopic tumor debulking with the goal of minimizing microscopic residual disease. We hypothesize that we can utilize overexpressed αVβ3 integrins in the tumor-associated neovasculature. Specific targeting is achieved by encapsulating fluorescent probes in FDA-approved PLGA-based nanoparticle (NP) coated with the peptide sequence arginine-glycine-aspartate (RGD), which binds with high affinity to these integrins. Materials and methods: Ovarian cancer xenograft is established intra- peritoneally (i.p.) in nude mice using cancer cells that stably express mCherry flu...
Here we report on a "configuration-dependent" mechanism of action for IL-15:IL-15Rα (he... more Here we report on a "configuration-dependent" mechanism of action for IL-15:IL-15Rα (heterodimeric IL-15, or hetIL-15), where the manner by which IL-15:IL-15Rα molecules are presented to target cells significantly impacts its function as a vaccine adjuvant. While the cellular mechanism of IL-15 transpresentation via IL-15Rα and its importance for IL-15 function have been described, the full impact of IL-15:IL-15Rα configuration on responding cells is not yet known. We found that transpresenting IL-15:IL-15Rα in multivalent fashion on the surface of antigen-encapsulating nanoparticles enhanced the ability of NP-treated dendritic cells (DC) to stimulate antigen-specific CD8+ T cell responses. Localization of multivalent IL-15:IL-15Rα and encapsulated antigen to the same DC led to maximal T cell responses. Strikingly, DCs incubated with IL-15:IL-15Rα-coated nanoparticles displayed higher levels of functional IL-15 on the cell surface, implicating a mechanism for nanoparticle-...
Proceedings of the 48th Design Automation Conference, 2011
Abstract Semiconducting nanowires (NWs) have the potential to function as highly sensitive and se... more Abstract Semiconducting nanowires (NWs) have the potential to function as highly sensitive and selective sensors for label-free detection of minute concentrations of target molecules. We discuss here an approach to NW sensors using CMOS (complementary metal-oxide-...
Vaccines for many infectious diseases are poorly developed or simply unavailable. There are signi... more Vaccines for many infectious diseases are poorly developed or simply unavailable. There are significant technological and practical design issues that contribute to this problem; thus, a solution to the vaccine problem will require a systematic approach to test the multiple variables that are required to address each of the design challenges. Nanoparticle technology is an attractive methodology for optimizing vaccine development because design variables can be tested individually or in combination. The biology of individual components that constitute an effective vaccine is often well understood and may be integrated into particle design, affording optimal immune responses to specific pathogens. Here, we review technological variables and design parameters associated with creating modular nanoparticle vaccine systems that can be used as vectors to protect against disease. Variables, such as the material and size of the core matrix, surface modification for attaching targeting ligand...
Vaccines that activate humoral and cell-mediated immune responses are urgently needed for many in... more Vaccines that activate humoral and cell-mediated immune responses are urgently needed for many infectious agents, including the flaviviruses dengue and West Nile (WN) virus. Vaccine development would be greatly facilitated by a new approach, in which nanoscale modules (Ag, adjuvant, and carrier) are assembled into units that are optimized for stimulating immune responses to a specific pathogen. Toward that goal, we formulated biodegradable nanoparticles loaded with Ag and surface modified with the pathogen-associated molecular pattern CpG oligodeoxynucleotides. We chose to evaluate our construct using a recombinant envelope protein Ag from the WN virus and tested the efficiency of this system in eliciting humoral and cellular responses and providing protection against the live virus. Animals immunized with this system showed robust humoral responses polarized toward Th1 immune responses compared with predominately Th2-biased responses with the adjuvant aluminum hydroxide. Immunizati...
There is a real need to develop new therapeutic strategies for African trypanosomiasis infections... more There is a real need to develop new therapeutic strategies for African trypanosomiasis infections. In our study, we developed a new drug delivery system of diminazene (DMZ), a trypanocidal drug registered for veterinary use. This drug candidate presents a limited efficacy, a poor affinity for brain tissue and instability. The development of colloidal formulations based on a porous cationic nanoparticle with an oily core ((70)DGNP(+)), has potentially two advantages: stabilization of the drug and potential targeting of the parasite. We analyzed two processes of drug loading: in process (DMZ was added during the preparation of (70)DGNP(+) at 80 °C) and post-loading (DMZ was mixed with a (70)DGNP(+) solution at room temperature). Poor stability of the drug was observed using the in process technique. When using the post-loading technique over 80% drug entrapment efficiency was obtained at a ratio of DMZ:phospholipids (wt:wt) &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 5%. Moreover, DMZ loaded into (70)DGNP(+) was found to be protected against oxidation and was stable for at least six months at 4 °C. Finally, in vitro tests on T.b. brucei showed an increased efficacy of DMZ loaded in (70)DGNP(+).
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Papers by Tarek Fahmy