Jonathan A. Copp

Cancer Cell Membrane-Coated Nanoparticles for Anticancer Vaccination and Drug Delivery

Cell-derived nanoparticles have been garnering increased attention due to their ability to mimic many of the natural properties displayed by their source cells. This top-down engineering approach can be applied toward the development of novel therapeutic strategies owing to the unique interactions enabled through the retention of complex antigenic information. Herein, we report on the biological functionalization of polymeric nanoparticles with a layer of membrane coating derived from cancer cells. The resulting core–shell nanostructures, which carry the full array of cancer cell membrane antigens, offer a robust platform with applicability toward multiple modes of anticancer therapy. We demonstrate that by coupling the particles with an immunological adjuvant, the resulting formulation can be used to promote a tumor-specific immune response for use in vaccine applications. Moreover, we show that by taking advantage of the inherent homotypic binding phenomenon frequently observed among tumor cells the membrane functionalization allows for a unique cancer targeting strategy that can be utilized for drug delivery applications.

A biomimetic nanosponge that absorbs pore-forming toxins

Detoxification treatments such as toxin-targeted anti-virulence therapy1, 2 offer ways to cleanse the body of virulence factors that are caused by bacterial infections, venomous injuries, and biological weaponry. Because existing detoxification platforms such as antisera3, monoclonal antibodies4, small-molecule inhibitors5, 6, and molecularly imprinted polymers7 act by targeting the molecular structures of the toxins, customized treatments are required for different diseases. Here we show a biomimetic toxin nanosponge that functions as a toxin decoy in vivo. The nanosponge, which consists of a polymeric nanoparticle core surrounded by red blood cell membranes, absorbs membrane-damaging toxins and diverts them away from their cellular targets. In a mouse model, the nanosponges markedly reduce the toxicity of staphylococcal alpha-hemolysin (α-toxin) and thus improve the survival rate of toxin-challenged mice. This biologically inspired toxin nanosponge presents a detoxification treatment that can potentially treat a variety of injuries and diseases caused by pore-forming toxins.

Folate-targeted nanoparticle delivery of chemo- and radiotherapeutics for the treatment of ovarian cancer peritoneal metastasis

Peritoneal metastasis is a major cause of morbidity and mortality in ovarian cancer. While intraperitoneal chemotherapy and radiotherapy have shown favorable clinical results, both are limited by their non-targeted nature. We aimed to develop a biologically targeted nanoparticle therapeutic for the treatment of ovarian cancer peritoneal metastasis. Folate-targeted nanoparticles encapsulating chemotherapy and/or radiotherapy were engineered. Paclitaxel (Ptxl) was used as the chemotherapeutic and yittrium-90 ((90)Y) was employed as the therapeutic radioisotope. Folate was utilized as the targeting ligand as most ovarian cancers overexpress the folate receptor. Nanoparticle characterization studies showed monodispersed particles with controlled Ptxl release. Folate targeting ligand mediated the uptake of NPs into tumor cells. In vitro efficacy studies demonstrated folate-targeted NPs containing chemoradiotherapy was the most effective therapeutic compared to folate-targeted NPs containing a single therapeutic or any non-targeted NP therapeutics. In vivo efficacy studies using an ovarian peritoneal metastasis model showed that folate-targeted NP therapeutics were significantly more effective than non-targeted NP therapeutics. Among the folate-targeted therapeutics, the NP containing chemoradiotherapy appeared to be the most effective. Our results suggest that folate-targeted nanoparticles containing chemoradiotherapy have the potential as a treatment for ovarian peritoneal metastasis.

Folate-targeted Polymeric Nanoparticle Formulation of Docetaxel is an Effective Molecularly Targeted Radiosensitizer with Efficacy Dependent on the Timing of Radiotherapy

Nanoparticle (NP) chemotherapeutics hold great potential as radiosensitizers. Their unique properties, such as preferential accumulation in tumors and their ability to target tumors through molecular targeting ligands, are ideally suited for radiosensitization. We aimed to develop a molecularly targeted nanoparticle formulation of docetaxel (Dtxl) and evaluate its property as a radiosensitizer. Using a biodegradable and biocompatible lipid-polymer NP platform and folate as a molecular targeting ligand, we engineered a folate-targeted nanoparticle (FT-NP) formulation of Dtxl. These NPs have sizes of 72 ± 4 nm and surface charges of -42 ± 8 mV. Using folate receptor overexpressing KB cells and folate receptor low HTB-43 cells, we showed folate-mediated intracellular uptake of NPs. In vitro radiosensitization studies initially showed FT-NP is less effective than Dtxl as a radiosensitizer. However, the radiosensitization efficacy is dependent on the timing of radiotherapy. In vitro radiosensitization conducted with irradiation given at the optimal time (24 h) showed FT-NP Dtxl is as effective as Dtxl. When FT-NP Dtxl is compared to Dtxl and nontargeted nanoparticle (NT-NP) Dtxl in vivo, FT-NP was found to be significantly more effective than Dtxl or NT-NP Dtxl as a radiosensitizer. We also confirmed that radiosensitization is dependent on timing of irradiation in vivo. In summary, FT-NP Dtxl is an effective radiosensitizer in folate-receptor overexpressing tumor cells. Time of irradiation is critical in achieving maximal efficacy with this nanoparticle platform. To the best of our knowledge, our report is the first to demonstrate the potential of molecularly targeted NPs as a promising new class of radiosensitizers.

Revival of the abandoned therapeutic wortmannin by nanoparticle drug delivery

One of the promises of nanoparticle (NP) carriers is the reformulation of promising therapeutics that have failed clinical development due to pharmacologic challenges. However, current nanomedicine research has been focused on the delivery of established and novel therapeutics. Here we demonstrate proof of the principle of using NPs to revive the clinical potential of abandoned compounds using wortmannin (Wtmn) as a model drug. Wtmn is a potent inhibitor of phosphatidylinositol 3′ kinase-related kinases but failed clinical translation due to drug-delivery challenges. We engineered a NP formulation of Wtmn and demonstrated that NP Wtmn has higher solubility and lower toxicity compared with Wtmn. To establish the clinical translation potential of NP Wtmn, we evaluated the therapeutic as a radiosensitizer in vitro and in vivo. NP Wtmn was found to be a potent radiosensitizer and was significantly more effective than the commonly used radiosensitizer cisplatin in vitro in three cancer cell lines. The mechanism of action of NP Wtmn radiosensitization was found to be through the inhibition of DNA-dependent protein kinase phosphorylation. Finally, NP Wtmn was shown to be an effective radiosensitizer in vivo using two murine xenograft models of cancer. Our results demonstrate that NP drug-delivery systems can promote the readoption of abandoned drugs such as Wtmn by overcoming drug-delivery challenges.

Clearance of pathological antibodies using biomimetic nanoparticles

Significance The selective depletion of disease-causing antibodies using nanoparticles offers a new model in the management of type II immune hypersensitivity reactions. The demonstration of pathophysiologically inspired nanoengineering serves as a valuable prototype for additional therapeutic improvements with the goal of minimizing therapy-related adverse effects. Through the use of cell membrane-cloaked nanoparticles, nanoscale decoys with strong affinity to pathological antibodies can be administered to disrupt disease processes in a minimally toxic manner. These biomimetic nanoparticles enable indiscriminate absorption of pathological antibodies regardless of their epitope specificities. This particular approach offers much promise in treating antibody-mediated autoimmune diseases, in which target antigens on susceptible cells can vary from patient to patient. Pathological antibodies have been demonstrated to play a key role in type II immune hypersensitivity reactions, resulting in the destruction of healthy tissues and leading to considerable morbidity for the patient. Unfortunately, current treatments present significant iatrogenic risk while still falling short for many patients in achieving clinical remission. In the present work, we explored the capability of target cell membrane-coated nanoparticles to abrogate the effect of pathological antibodies in an effort to minimize disease burden, without the need for drug-based immune suppression. Inspired by antibody-driven pathology, we used intact RBC membranes stabilized by biodegradable polymeric nanoparticle cores to serve as an alternative target for pathological antibodies in an antibody-induced anemia disease model. Through both in vitro and in vivo studies, we demonstrated efficacy of RBC membrane-cloaked nanoparticles to bind and neutralize anti-RBC polyclonal IgG effectively, and thus preserve circulating RBCs.

Safe and immunocompatible nanocarriers cloaked in RBC membranes for drug delivery to treat solid tumors

The therapeutic potential of nanoparticle-based drug carriers depends largely on their ability to evade the host immune system while delivering their cargo safely to the site of action. Of particular interest are simple strategies for the functionalization of nanoparticle surfaces that are both inherently safe and can also bestow immunoevasive properties, allowing for extended blood circulation times. Here, we evaluated a recently reported cell membrane-coated nanoparticle platform as a drug delivery vehicle for the treatment of a murine model of lymphoma. These biomimetic nanoparticles, consisting of a biodegradable polymeric material cloaked with natural red blood cell membrane, were shown to efficiently deliver a model chemotherapeutic, doxorubicin, to solid tumor sites for significantly increased tumor growth inhibition compared with conventional free drug treatment. Importantly, the nanoparticles also showed excellent immunocompatibility as well as an advantageous safety profile compared with the free drug, making them attractive for potential translation. This study demonstrates the promise of using a biomembrane-coating approach as the basis for the design of functional, safe, and immunocompatible nanocarriers for cancer drug delivery.

Hydrogel Retaining Toxin‐Absorbing Nanosponges for Local Treatment of Methicillin‐Resistant Staphylococcus aureus Infection

Targeting virulence factors such as bacterial toxins represents an attractive antimicrobial approach with potential advantages of expanding the repertoire of bacterial targets, preserving the host endogenous microbiome, and lowering selective pressure for resistance development.[1, 2] Among various toxins, pore-forming toxins (PFTs) are the most common class of bacterial protein toxins and constitute important bacterial virulence factors.[3] These toxins disrupt cells by forming pores on cellular membranes and altering their permeability for bioactivity.[4] However, the majority of current toxin targeting strategies, such as antisera,[5] monoclonal antibodies,[6, 7] small-molecule inhibitors,[8, 9] and molecularly imprinted polymers,[10] relies primarily on structure-specific epitopic binding and custom synthesis is required to match specific toxins. As a result, the enormous diversity of PFTs presents a serious challenge to devise an effective detoxification platform against bacterial infections. To address this challenge, a unique red blood cell (RBC) membrane-coated nanoparticle system has been recently developed by wrapping intact RBC membrane onto polymeric nanoparticles (denoted ‘nanosponges’) for broad detoxification applications.[11, 12] The term ‘nanosponges’ is used to describe the unique capability of the RBC membrane-coated nanoparticles for non-specifically ‘soaking up’ a broad spectrum of PFTs. Different from existing detoxification strategies, the nanosponges target the membrane-disrupting mechanism common to PFTs; thereby offering an all-purpose toxin decoy strategy to absorb various types of PFTs regardless of their molecular structures.[12]

Alkalotics anonymous: severe metabolic alkalosis.

Patients may exclude vital details from the medical history,complicating the diagnostic process. This was certainly truewhen a 64-year-old man was brought to the emergencydepartment by his sister after 3 weeks of decreased oralintake, worsening confusion, and difficulty walking.The patient was a poor historian; most information wasobtained from his sister. He had a history of hypertension,gastroesophageal reflux disease, post-traumatic stress dis-order, and alcohol abuse. His sister noted that he had beenmore withdrawn in the previous several weeks; his recentdiet consisted of only Pepsi and alcohol. He took no pre-scription medications, had lost approximately 30 poundsover the preceding month, and had been vomiting severaltimes per week during this period.

Organ-specific metastases obtained by culturing colorectal cancer cells on tissue-specific decellularized scaffolds

Metastatic disease remains the primary cause of mortality in cancer patients. Yet the number of available in vitro models to study metastasis is limited by challenges in the recapitulation of the metastatic microenvironment in vitro, and by difficulties in maintaining colonized-tissue specificity in the expansion and maintenance of metastatic cells. Here, we show that decellularized scaffolds that retain tissue-specific extracellular-matrix components and bound signalling molecules enable, when seeded with colorectal cancer cells, the spontaneous formation of three-dimensional cell colonies that histologically, molecularly and phenotypically resemble in vivo metastases. Lung and liver metastases obtained by culturing colorectal cancer cells on, respectively, lung and liver decellularized scaffolds retained their tissue-specific tropism when injected in mice. We also found that the engineered metastases contained signet ring cells, which has not previously been observed ex vivo. A culture system with tissue-specific decellularized scaffolds represents a simple and powerful approach for the study of organ-specific cancer metastases.Metastatic disease remains the primary cause of mortality in cancer patients. Yet the number of available in vitro models to study metastasis is limited by challenges in the recapitulation of the metastatic microenvironment in vitro, and by difficulties in maintaining colonized-tissue specificity in the expansion and maintenance of metastatic cells. Here, we show that decellularized scaffolds that retain tissue-specific extracellular-matrix components and bound signalling molecules enable, when seeded with colorectal cancer cells, the spontaneous formation of three-dimensional cell colonies that histologically, molecularly and phenotypically resemble in vivo metastases. Lung and liver metastases obtained by culturing colorectal cancer cells on, respectively, lung and liver decellularized scaffolds retained their tissue-specific tropism when injected in mice. We also found that the engineered metastases contained signet ring cells, which has not previously been observed ex vivo. A culture system with tissue-specific decellularized scaffolds represents a simple and powerful approach for the study of organ-specific cancer metastases.A cell-culture method involving decellularized tissue scaffolds enables the spontaneous formation of cell colonies that phenotypically recapitulate in vivo organ-specific cancer metastases.