LNP Applications Highlight: Avanti Lipids For Theranostic Medicine

Posted on August 18, 2021

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The term theranostic comes from the combination of two words: therapeutic and diagnostic. This rapidly developing field of research is dedicated to providing unique treatment opportunities that have improved efficacy, more targeted delivery, and reduced off-target effects. These combinatorial treatment strategies offer the ability to first diagnose and then treat a disease all in one. The theranostic approach relies heavily on lipid-based technology such as liposomal and lipid nanoparticle delivery systems. Lipid-based delivery technology offers the unique ability to functionalize the system to achieve desired delivery properties such as low renal clearance, reduced immunogenicity and antigenicity, and high loading capacities of therapeutic agents. Avanti is at the forefront of lipid-based delivery systems technology and our lipids are being used in research for various theranostic approaches.

In 2019, a research lab from Yonsei University and Kumamoto University published a study using anti-cancer siRNAs delivered by lipid nanocarriers for theranostics of triple-negative breast cancer. Aptamer-guided gene delivery, particularly for the delivery of siRNA, has been studied extensively in recent years. Aptamers are short DNA or RNA molecules that can selectively bind to a specific target. These targets can be proteins, peptides, carbohydrates, small molecule toxins, or even live cells. They are synthesized and screened using a large oligonucleotide library called SELEX (sequential evolution of ligands by exponential enrichment).

Aptamer-siRNA conjugates face many challenges despite the ability to specifically target. Nucleases easily degrade nucleic acid complexes in biological fluids and even if the genes are delivered to their desired destination, reaching the cytoplasm is difficult because they are easily degraded by endosomal enzymes. These challenges present a remarkable opportunity for the use of lipid-based delivery systems. Cationic lipid carrier systems have many advantageous properties that can be used to safely deliver siRNA therapeutics to their desired targets. Cationic lipid carrier systems have efficient cellular uptake, a high capacity for loading siRNA, and the ability to protect genetic material from nucleases and endosomal enzymes. Combining the targeting ability of aptamers and the protection and delivery abilities of lipid carriers could offer novel theranostics. So, the research teams at Yonsei University and Kumamoto University set out to make an aptamer-coated lipid nanocarrier and test their hypothesis.

The study demonstrated a combinatorial anti-cancer treatment using siRNA that interferes with cell proliferation and PKC-1 inhibiting tumor cell migration. The conjugated aptamer-lipid carrier system was prepared by using Avanti’s DSPE-mPEG2000-maleimide and a reactive aptamer. Then the conjugated aptamer-DSPE-mPEG2000 was added to DMKE (cationic lipid), cholesterol, and quantum dots (QD). Once the lipid nanocarriers were prepared they were mixed with siRNA. QDs are fluorescent and in this case, are being used as the “diagnostic” portion of theranostic medicine. The siRNA was efficiently delivered to the tumor tissues and reduced target gene expression which resulted in inhibition of tumor growth. These novel aptamer-lipid nanoparticle conjugates containing siRNA and QDs could be used to diagnose and treat cancers such as triple-negative breast cancer.

It is always exciting to see what research is being done with our lipids! If you are interested in conducting your research involving the preparation or use of lipid nanoparticles, please visit our brand new Lipid Nanoparticle (LNP) Technology page.

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