22 research outputs found
Dendrimer Conjugation Enhances Tumor Penetration and Cell Kill of Doxorubicin in 3D Coculture Lung Cancer Models
Background: Doxorubicin (DOX) is a potent chemotherapeutic widely used for solid tumors (1). Despite high efficacy in 2D cell culture, DOX efficacy does not translate to in vivo lung cancer models (2). Major side effects such as cardiotoxicity may be alleviated with nano-based drug delivery systems (nanoDDS). However, tumor penetration of DOX and DOX-nanoDDS is largely unknown and is an additional barrier to effective clinical therapy (3). Here we describe a nanoDDS capable of enhancing the penetration of DOX.
Methods: DOX was conjugated to generation 4 poly(amido-amine) dendrimers through (GFLG) tumor- liable bond. G4SA-GFLG-DOX was synthesized/characterized. spheroids were formed of (A549) lung adenocarcinoma cells and (3T3) fibroblasts. Spheroids were characterized for ECM components with immunohistochemistry. Confocal microscopy was used to evaluate the penetration, internalization, and colocalization of DOX and G4SA-GFLG-DOX. MTT assay and Caspase 3/7 to assess 2D and 3D cytotoxicity. Flow cytometry to determine cells uptake.
Results: DOX conjugation to dendrimer resulted in G4SA-GFLG-DOX with ~5.5 DOX, 10±1 nm hydrodynamic diameter, and a -17±3 mV zeta-potential. Spheroids of (A549:3T3) were ECM- rich, developed ECM containing collagen-I, hyaluronan, laminin, and fibronectin. While DOX and G4SA-GFLG-DOX had similar toxicities in 2D model, G4SA-GFLG-DOX demonstrated a 3.1-fold greater penetration into spheroids compared to DOX and correlated to a greater efficacy as measured by caspase 3/7 activity. Also, flow cytometry showed higher uptake of G4SA- GFLG-DOX in cancer cells compared to fibroblasts.
Conclusion: The work demonstrates enhanced penetration of DOX, via dendrimer conjugation, into an ECM- rich 3D lung cancer model. The enhanced penetration of G4SA-GFLG-DOX correlated with greater antitumor efficacy.
Acknowledgements: We acknowledge partial financial support from the Center for Pharmaceutical Engineering and Sciences - School of Pharmacy at VCU. This study was supported by VCU Quest for Distinction and NSF (DRM #1508363). Microscopy was performed at the VCU Microscopy Facility, supported, in part, by funding from NIH-NCI Cancer Center Support Grant P30 CA016059. RA would like to acknowledge King Faisal University (KFU) and Saudi Arabian Cultural Mission (SACM) for a scholarship.https://scholarscompass.vcu.edu/gradposters/1091/thumbnail.jp
An atlas of over 90.000 conserved noncoding sequences provides insight into crucifer regulatory regions
Despite the central importance of noncoding DNA to gene regulation and evolution, understanding of the extent of selection on plant noncoding DNA remains limited compared to that of other organisms. Here we report sequencing of genomes from three Brassicaceae species (Leavenworthia alabamica, Sisymbrium irio and Aethionema arabicum) and their joint analysis with six previously sequenced crucifer genomes. Conservation across orthologous bases suggests that at least 17% of the Arabidopsis thaliana genome is under selection, with nearly one-quarter of the sequence under selection lying outside of coding regions. Much of this sequence can be localized to approximately 90,000 conserved noncoding sequences (CNSs) that show evidence of transcriptional and post-transcriptional regulation. Population genomics analyses of two crucifer species, A. thaliana and Capsella grandiflora, confirm that most of the identified CNSs are evolving under medium to strong purifying selection. Overall, these CNSs highlight both similarities and several key differences between the regulatory DNA of plants and other species
Quantitative Detection of PLGA Nanoparticle Degradation in Tissues following Intravenous Administration
The
biodegradable polymer polyÂ(lactic-<i>co</i>-glycolic)
acid (PLGA) has been extensively utilized and investigated as a drug
delivery system. Although <i>in vivo</i> biodegradation
(at specific administration sites only) of PLGA-based drug delivery
constructs, such as foams and microparticles, has been studied, quantitative <i>in vivo</i> biodegradation of distributed polymer nanoparticles
has not been accomplished and is quintessential for designing formulations
to achieve desired pharmacokinetic properties of a drug in a target
tissue. We determined the <i>in vivo</i> degradation kinetics
of PLGA nanoparticles, of two sizes, distributed in liver, spleen,
and lungs following intravenous administration. In addition, we simultaneously
determined the amount of polymer in tissues. Nanoparticle degradation <i>in vitro</i> and <i>in vivo</i> appears to be a first-order
process, and useful correlations were obtained between <i>in
vitro</i> and <i>in vivo</i> tissue degradation of
the nanoparticles. The ability to detect <i>in vivo</i> degradation
and biodistribution of polymer nanoparticles is a significant milestone
for the rational design of degradable nanoparticle-based drug delivery
systems capable of delivering the therapeutic agent in a closely predictable
manner to target tissue
Effect of the Route of Administration and PEGylation of Poly(amidoamine) Dendrimers on Their Systemic and Lung Cellular Biodistribution
There
are many opportunities in the development of oral inhalation
(oi) formulations for the delivery of small molecule therapeutics
and biologics to and through the lungs. Nanocarriers have the potential
to play a key role in advancing oi technologies and pushing the boundary
of the pulmonary delivery market. In this work we investigate the
effect of the route of administration and PEGylation on the systemic
and lung cellular biodistribution of generation 3, amino-terminated
polyÂ(amidoamine) (PAMAM) dendrimers (G3NH2). Pharmacokinetic profiles
show that the dendrimers reach their peak concentration in systemic
circulation within a few hours after pulmonary delivery, independent
of their chemistry (PEGylated or not), charge (+24 mV for G3NH2 vs
â3.7 mV for G3NH2-24PEG1000), or size (5.1 nm for G3NH2 and
9.9 nm for G3NH2-24PEG1000). However, high density of surface modification
with PEG enhances pulmonary absorption and the peak plasma concentration
upon pulmonary delivery. The route of administration and PEGylation
also significantly impact the whole body and local (lung cellular)
distribution of the dendrimers. While ca. 83% of G3NH2 is found in
the lungs upon pulmonary delivery at 6.5 h post administration, only
2% reached the lungs upon intravenous (iv) delivery. Moreover, no
measurable concentration of either G3NH2 or G3NH2-24PEG1000 is found
in the lymph nodes upon iv administration, while these are the tissues
with the second highest mass distribution of dendrimers post pulmonary
delivery. Dendrimer chemistry also significantly impacts the (cellular)
distribution of the nanocarriers in the lung tissue. Upon pulmonary
delivery, approximately 20% of the lung endothelial cells are seen
to internalize G3NH2-24PEG1000, compared to only 6% for G3NH2. Conversely,
G3NH2 is more readily taken up by lung epithelial cells (35%) when
compared to its PEGylated counterpart (24%). The results shown here
suggest that both the pulmonary route of administration and dendrimer
chemistry combined can be used to passively target tissues and cell
populations of great interest, and can thus be used as guiding principles
in the development of dendrimer-based drug delivery strategies in
the treatment of medically relevant diseases including lung ailments
as well as systemic disorders
Unique insights into the intestinal absorption, transit, and subsequent biodistribution of polymer-derived microspheres
Physicochemical and In Vitro Evaluation of Drug Delivery of an Antibacterial Synthetic Benzophenone in Biodegradable PLGA Nanoparticles
Due to the increasing incidents of antimicrobial-resistant pathogens, the development of new antibiotics and their efficient formulation for suitable administration is crucial. Currently, one group of promising antimicrobial compounds are the benzophenone tetra-amides which show good activity even against gram-positive, drug-resistant pathogens. These compounds suffer from poor water solubility and bioavailability. It is therefore important to develop dosage forms which can address this disadvantage while also maintaining efficacy and potentially generating long-term exposures to minimize frequent dosing. Biodegradable nanoparticles provide one solution, and we describe here the encapsulation of the experimental benzophenone-based antibiotic, SV7. Poly-lactic-co-glycolic-acid (PLGA) nanoparticles were optimized for their physicochemical properties, their encapsulation efficiency, sustained drug release as well as antimicrobial activity. The optimized formulation contained particles smaller than 200Â nm with a slightly negative zeta potential which released 39% of their drug load over 30Â days. This formulation maintains the antibacterial activity of SV7 while minimizing the impact on mammalian cells
Conjugation to Poly(amidoamine) Dendrimers and Pulmonary Delivery Reduce Cardiac Accumulation and Enhance Antitumor Activity of Doxorubicin in Lung Metastasis
Lung
is one of the most common sites to which almost all other
primary tumors metastasize. The major challenges in the chemotherapy
of lung metastases include the low drug concentration found in the
tumors and high systemic toxicity upon systemic administration. In
this study, we combine local lung delivery and the use of nanocarrier-based
systems for improving pharmacokinetics and biodistribution of the
therapeutics to fight lung metastases. We investigate the impact of
the conjugation of doxorubicin (DOX) to carboxyl-terminated polyÂ(amidoamine)
dendrimers (PAMAM) through a bond that allows for intracellular-triggered
release, and the effect of pulmonary delivery of the dendrimerâDOX
conjugate in decreasing tumor burden in a lung metastasis model. The
results show a dramatic increase in efficacy of DOX treatment of the
melanoma (B16-F10) lung metastasis mouse model upon pulmonary administration
of the drug, as indicated by decreased tumor burden (lung weight)
and increased survival rates of the animals (male C57BL/6) when compared
to iv delivery. Conjugation of DOX further increased the therapeutic
efficacy upon lung delivery as indicated by the smaller number of
nodules observed in the lungs when compared to free DOX. These results
are in agreement with the biodistribution characteristics of the DOX
upon pulmonary delivery, which showed a longer lung accumulation/retention
compared to iv administration. The distribution of DOX to the heart
tissue is also significantly decreased upon pulmonary administration,
and further decreased upon conjugation. The results show, therefore,
that pulmonary administration of DOX combined to conjugation to PAMAM
dendrimer through an intracellular labile bond is a potential strategy
to enhance the therapeutic efficacy and decrease systemic toxicity
of DOX