Milk exosomes - Natural nanoparticles for siRNA delivery

• Published in: Cancer letters 2019-05, Vol.449, p.186-195
• Main Authors: Aqil, Farrukh, Munagala, Radha, Jeyabalan, Jeyaprakash, Agrawal, Ashish K., Kyakulaga, Al-Hassan, Wilcher, Sarah A., Gupta, Ramesh C.
• Format: Article
• Language: English
• Subjects: A549 Cells; Acids; AKT protein; Animals; Biocompatibility; Cancer; Cell culture; Cell Proliferation - drug effects; Cow's milk; Dendritic cells; Dose-Response Relationship, Drug; Drug delivery systems; Epidermal growth factor receptors; ErbB Receptors - antagonists & inhibitors; Exosomes; Exosomes - chemistry; Female; Fibroblasts; Folic acid; Folic Acid - chemistry; Gene silencing; Humans; Lung cancer; Lung Neoplasms - drug therapy; Lung Neoplasms - genetics; MAP kinase; Mice; Milk; Milk - cytology; Milk exosomes; Nanoparticles; Ovarian cancer; Payloads; Proto-Oncogene Proteins p21(ras) - antagonists & inhibitors; RNA, Small Interfering - administration & dosage; RNA, Small Interfering - pharmacology; siRNA; Vascular endothelial growth factor; Vascular Endothelial Growth Factor A - antagonists & inhibitors; Xenograft Model Antitumor Assays; Xenografts
• ISSN: 0304-3835; 1872-7980
• DOI: 10.1016/j.canlet.2019.02.011

Gene-silencing with targeted siRNAs has great potential as a therapeutic approach for various diseases including cancer. However, intracellular delivery of siRNA is challenging. We used bovine milk exosomes as a novel system for siRNA delivery. First, we demonstrated that exosomes can deliver endogenous RNA payloads into recipient cells. Next, we loaded siRNA against specific genes including VEGF, EGFR, AKT, MAPK, and KRAS. We utilized 5′−32P-labeled siKRAS as a tracer and found exosome loading with siRNA could be variable. We demonstrated that the siRNA of loaded exosomes is stable and resist degradation. Our results indicated that siRNAs against target genes ranged from 2 to 10-fold knockdown in expression levels in various cancers. Since mutated KRAS has been implicated in the development of various cancers including lung cancer, we tested a mutant-allele specific siRNA against KRASG12S, in A549 cells. We observed a dose-dependent anti-proliferative activity against A549 cells treated with exosomes carrying siKRASG12S. We observed significant inhibition of A549 tumor xenografts in animals treated with folic acid-functionalized exosomes carrying siKRAS. In summary, milk-derived exosomes represent a viable natural nano-carrier for the delivery of siRNA for therapeutic application against cancer. [Display omitted] •Milk exosomes represent a viable natural nano-carrier for the delivery of siRNA.•Exosomes were loaded with siRNA using a chemical transfecting reagent, Exo-Fect.•siRNA loaded exosomes demonstrated 2–10-fold knockdown.•Exosome carrying siKRAS showed dose-dependent antiproliferative activity.•Folic acid-functionalized Exo-siKRAS significantly inhibited lung tumor xenograft.