title: Knockdown of antiapoptotic genes in breast cancer cells by siRNA loaded into hybrid nanoparticles.
abstract: Tumorigenesis is related to an imbalance in controlling mechanisms of apoptosis. Expression of the genes BCL-2 and BCL-xL results in the promotion of cell survival by inhibiting apoptosis. Thus, a novel approach to suppress antiapoptotic genes is the use of small interfering RNA (siRNA) in cancer cells. However, there are some limitations for the application of siRNA such as the need for vectors to pass the cell membrane and deliver the nucleic acid. In this study CaP-siRNA-PEG-polyanion hybrid nanoparticles were developed to promote siRNA delivery to cultured human breast cancer cells (MCF-7) in order to evaluate whether the silencing of antiapoptotic genes BCL-2 and BCL-xL by siRNA would increase cancer cell death. After 48 h of incubation the expression of BCL-2 and BCL-xL genes decreased to 49% and 23%, respectively. The siRNA sequence used induced cancer cell death at a concentration of 200 nM siRNA after 72 h of incubation. As the targeted proteins are related to the resistance to chemotherapeutic drugs, the nanocarriers systems were also tested in the presence of doxorubicin (DOX). The results showed a significant reduction in the CC50of the DOX, after silencing the antiapoptotic genes. In addition, an increase in apoptotic cell counts for both incubations conditions was observed as well. In conclusion, silencing antiapoptotic genes such as BCL-2 and BCL-xL through the use of siRNA carried by hybrid nanoparticles showed to be effective in vitro, and presents a promising strategy for pre-clinical analysis, especially when combined with DOX against breast cancer.
authors.affiliation: Post-graduation Course in Biochemistry, Federal University of Santa Catarina, Rua Pio Duarte Silva, 241, 88037-000 Florianópolis-SC-, Brazil. Biology Department, Federal Institute of Education, Science and Technology, Rua Mauro Ramos, 89020-300 Florianópolis-SC, Brazil.
authors.forename: Leônidas João
authors.initials: LJ
authors.lastname: de Mello
authors.forename: Gabriela Regina Rosa
authors.initials: GR
authors.lastname: Souza
authors.forename: Evelyn
authors.initials: E
authors.lastname: Winter
authors.forename: Adny Henrique
authors.initials: AH
authors.lastname: Silva
authors.forename: Frederico
authors.initials: F
authors.lastname: Pittella
authors.forename: Tânia Beatriz
authors.initials: TB
authors.lastname: Creczynski-Pasa
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology; D017209:Apoptosis / Q000235:genetics*; D001943:Breast Neoplasms / Q000235:genetics / Q000473:pathology / Q000628:therapy*; D002470:Cell Survival / Q000235:genetics; D004317:Doxorubicin / Q000494:pharmacology; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D055785:Gene Knockdown Techniques; D006801:Humans; D061986:MCF-7 Cells; D053758:Nanoparticles / Q000008:administration & dosage / Q000737:chemistry / Q000627:therapeutic use*; D011092:Polyethylene Glycols / Q000737:chemistry; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000235:genetics / Q000378:metabolism; D034741:RNA, Small Interfering / Q000008:administration & dosage*; D051020:bcl-X Protein / Q000235:genetics / Q000378:metabolism
chemical_list: D000970:Antineoplastic Agents; C494811:BCL2L1 protein, human; D019253:Proto-Oncogene Proteins c-bcl-2; D034741:RNA, Small Interfering; D051020:bcl-X Protein; D011092:Polyethylene Glycols; D004317:Doxorubicin