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Principal Investigator: CYRUS R SAFINYA
Organization: UNIVERSITY OF CALIFORNIA SANTA BARBARA
Fiscal Year: 2020
Award: $197,966
Funding agency: National Institute of General Medical Sciences
ABSTRACT (PUBLICLY RELEASABLE)
The current level of research activity involving gene therapy with either synthetic vectors
(carriers) or engineered viruses is unprecedented. Liposomes are the most widely studied
nonviral carriers worldwide for nucleic acid (NA) and drug delivery applications. Cationic
liposomes (CLs) are relatively safe nonviral vectors used in ongoing clinical trials. CLs may
either be complexed via electrostatic interactions with therapeutic NAs (anionic DNA or short
interfering RNA) for gene delivery and silencing, or used as vectors of potent cytotoxic
hydrophobic drugs, encapsulated within their lipid bilayer, in cancer therapeutics. Among the
biggest advantages of nonviral vectors (over viral vectors which are currently more efficient in in
vivo settings) are their safety, their low immunogenicity and their ability to transfer entire genes
(containing coding and noncoding sequences) and regulatory sequences into cells (currently not
feasible with engineered viruses because of capsid size limitations). The development of nonviral
lipid-based vectors with efficacy competitive with viral vectors in vivo will require a mechanistic
understanding of how synthetic vectors may be functionalized to overcome the major
intracellular hurdle of endosomal escape. Successful endosomal escape is required for release of
therapeutic nucleic acid within the cell cytosol and therefore maximum efficacy.
The first aim of our current award is to employ modern biophysical and synthetic
approaches to the rational design of functionalized CL–NA nanoparticles (NPs) with synergistic,
complementary dual-function PEG-lipid and fusogenic components for optimized endosomal
escape. Modern methods of organic and solid phase chemistry will be employed to synthesize
dual-function PEG-lipids with cell targeting and endosome escaping properties. The second aim
of our current award is to optimize efficacy of a new class of CL-based carriers of
the hydrophobic drug paclitaxel (PTX) for cancer therapeutics. (PTX is among the most widely
used cancer chemotherapy drugs to treat ovarian, breast, lung, pancreatic, and other cancers and
is included in the World Health Organization’s List of Essential Medicines.) This will be
achieved by developing a mechanistic understanding of the relation between physical and
chemical properties of the carrier (i.e. size of the functionalized CL carrier, membrane
spontaneous curvature, and lipid tail structure) and functional efficacy (i.e. PTX membrane
solubility, cell uptake of vector and PTX delivery leading to cytotoxicity against human cancer
cells). The broad, long-term objective of our research is to develop a fundamental science base
through mechanistic studies that will lead to the design and synthesis of nonviral vectors of
nucleic acids and hydrophobic drugs for gene and cancer therapeutics.
We use fluorescence live-cell imaging with quantitative particle tracking to visualize
complex pathways and interactions with cells, and established assays in low and high serum
conditions to measure transfection efficiencies (for CL-NA vectors) and NP antitumor efficacy
(for CL-hydrophobic drug based vectors). Synchrotron X-ray diffraction (and when required
cryo-TEM) is used for structure determination. Our capabilities in custom synthesis via modern
methods of organic chemistry are essential for the success of both goals.
Successful outcomes in our fundamental mechanistic studies (major aims 1 and 2) will have a
major impact on the creation of efficient and safe CL vectors of nucleic acids and hydrophobic
drugs with anti-tumor activity.
Terms: <Anzatax><Asotax><Assay><Award><Bioassay><Biologic Assays><Biological Assay><Biophysics><Blood Serum><Breast><Bristaxol><Cancers><Capsid><Cations><Cell Body><Cells><Chemistry><Chemotherapy Protocol><Chemotherapy Regimen><Chemotherapy, Cancer, General><Chemotherapy-Oncologic Procedure><Clinical Trials><Code><Coding System><Combination Chemotherapy Regimen><Complex><Custom><Cytosol><DNA><DNA Therapy><Deoxyribonucleic Acid><Development><Drug Delivery><Drug Delivery Systems><Drugs><Electrostatics><Encapsulated><Endosomes><Engineering><Fluorescence><Functional RNA><Gene Delivery><Gene Inactivation><Gene Silencing><Gene Transfer Clinical><Genes><Genetic Intervention><Goals><Grant><Human><Hydrophobicity><Lipid Bilayers><Lipids><Liposomal><Liposomes><Lung><Lung Respiratory System><Lytotoxicity><Malignant Cell><Malignant Neoplasms><Malignant Tumor><Measures><Medication><Medicine><Membrane><Methods><Modern Man><Modernization><Non-Coding><Non-Coding RNA><Non-Viral Vector><Non-translated RNA><Noncoding RNA><Nontranslated RNA><Nucleic Acids><Organic Chemistry><Outcome><Ovarian><Paclitaxel><Paclitaxel (Taxol)><Pancreas><Pancreatic><Pathway interactions><Pharmaceutic Preparations><Pharmaceutical Preparations><Phase><Praxel><Property><Quimioterapia><Receptosomes><Research><Research Activity><Safety><Science><Serum><Short interfering RNA><Small Interfering RNA><Solid><Solubility><Structure><Synchrotrons><Tail><Taxol><Taxol A><Taxol Konzentrat><Therapeutic><Transfection><Untranslated RNA><Viral Vector><Virus><World Health Organization><X ray diffraction><X ray diffraction analysis><Xray diffraction><base><biophysical foundation><biophysical principles><biophysical sciences><cancer cell><cancer chemotherapy><chemical property><cytotoxic><cytotoxicity><design><designing><developmental><drug/agent><gene therapy><gene-based therapy><genetic therapy><genomic therapy><immunogenicity><in vivo><lipid bilayer membrane><liposomal carrier><liposomal nanocarrier><liposomal vehicle><liposome vector><live cell image><live cell imaging><live cellular image><live cellular imaging><malignancy><membrane structure><nano particle><nano-sized particle><nanoparticle><nanosized particle><neoplasm/cancer><noncoding><nonviral vector><nucleic acid-based therapeutics><parent project><particle><pathway><physical property><pulmonary><siRNA><success><therapeutic nucleic acids><transcriptional silencing><tumor><uptake><vector>