title: A nanoformulation of siRNA and its role in cancer therapy: in vitro and in vivo evaluation.
abstract: Overexpression of anti-apoptotic Bcl-2 is often observed in a wide variety of human cancers. It prevents the induction of apoptosis in neoplastic cells and contributes to resistance to chemotherapy. RNA interference has emerged as an efficient and selective technique for gene silencing. The potential to use small interfering RNA (siRNA) as a therapeutic agent for the treatment of cancer has elicited a great deal of interest. However, insufficient cellular uptake and poor stability have limited its therapeutic applications. The purpose of this study was to prepare chitosan nanoparticles via ionic gelation of chitosan by tripolyphosphate for effective delivery of siRNA to silence the anti-apoptotic Bcl-2 gene in neoplastic cells. Chitosan nanoparticles loaded with siRNA were in the size range 190 to 340 nm with a polydispersive index ranging from 0.04 to 0.2. They were able to completely bind with siRNA, provide protection against nuclease degradation, and enhance the transfection. Cell culture studies revealed that nanoparticles with entrapped siRNA could efficiently silence the antiapoptotic Bcl-2 gene. Studies on Swiss albino mice showed that siRNA could be effectively delivered through nanoparticles. There was significant decrease in the tumor volume. Blocking the expression of anti-apoptotic Bcl-2 can enhance the sensitivity of cancerous cells to anti-cancer drugs and the apoptosis rate. Therefore, nanoformulations with siRNA can be promoted as an adjuvant therapy in combination with anti-cancer drugs.
authors.affiliation: Department of Pharmaceutical Biotechnology, Manipal College of Pharmaceutical Sciences, Manipal University, Manipal, Karnataka, India-576104.
authors.forename: Hitesh
authors.initials: H
authors.lastname: Jagani
authors.forename: Josyula Venkata
authors.initials: JV
authors.lastname: Rao
authors.forename: Vasanth Raj
authors.initials: VR
authors.lastname: Palanimuthu
authors.forename: Raghu Chandrashekar
authors.initials: RC
authors.lastname: Hariharapura
authors.forename: Sagar
authors.initials: S
authors.lastname: Gang
mesh_terms: D017209:Apoptosis / Q000187:drug effects; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D048271:Chitosan / Q000737:chemistry*; D004339:Drug Compounding; D006801:Humans; D008855:Microscopy, Electron, Scanning; D053758:Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D010316:Particle Size; D011122:Polyphosphates / Q000737:chemistry; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism; D034622:RNA Interference; D020871:RNA Stability; D034741:RNA, Small Interfering / Q000235:genetics*; D014162:Transfection / Q000379:methods*; D047368:Tumor Burden / Q000187:drug effects
chemical_list: D011122:Polyphosphates; D019253:Proto-Oncogene Proteins c-bcl-2; D034741:RNA, Small Interfering; D048271:Chitosan; C005692:triphosphoric acid