title: TLR9-mediated siRNA delivery for targeting of normal and malignant human hematopoietic cells in vivo.
abstract: STAT3 operates in both cancer cells and tumor-associated immune cells to promote cancer progression. As a transcription factor, it is a highly desirable but difficult target for pharmacologic inhibition. We have recently shown that the TLR9 agonists CpG oligonucleotides can be used for targeted siRNA delivery to mouse immune cells. In the present study, we demonstrate that a similar strategy allows for targeted gene silencing in both normal and malignant human TLR9(+) hematopoietic cells in vivo. We have developed new human cell-specific CpG(A)-STAT3 siRNA conjugates capable of inducing TLR9-dependent gene silencing and activation of primary immune cells such as myeloid dendritic cells, plasmacytoid dendritic cells, and B cells in vitro. TLR9 is also expressed by several human hematologic malignancies, including B-cell lymphoma, multiple myeloma, and acute myeloid leukemia. We further demonstrate that oncogenic proteins such as STAT3 or BCL-X(L) are effectively knocked down by specific CpG(A)-siRNAs in TLR9(+) hematologic tumor cells in vivo. Targeting survival signaling using CpG(A)-siRNAs inhibits the growth of several xenotransplanted multiple myeloma and acute myeloid leukemia tumors. CpG(A)-STAT3 siRNA is immunostimulatory and nontoxic for normal human leukocytes in vitro. The results of the present study show the potential of using tumoricidal/immunostimulatory CpG-siRNA oligonucleotides as a novel 2-pronged therapeutic strategy for hematologic malignancies.
authors.affiliation: Department of Cancer Immunotherapeutics and Tumor Immunology, Beckman Research Institute at City of Hope, Duarte, CA 91010, USA.
authors.forename: Qifang
authors.initials: Q
authors.lastname: Zhang
authors.forename: Dewan Md Sakib
authors.initials: DM
authors.lastname: Hossain
authors.forename: Sergey
authors.initials: S
authors.lastname: Nechaev
authors.forename: Anna
authors.initials: A
authors.lastname: Kozlowska
authors.forename: Wang
authors.initials: W
authors.lastname: Zhang
authors.forename: Yong
authors.initials: Y
authors.lastname: Liu
authors.forename: Claudia M
authors.initials: CM
authors.lastname: Kowolik
authors.forename: Piotr
authors.initials: P
authors.lastname: Swiderski
authors.forename: John J
authors.initials: JJ
authors.lastname: Rossi
authors.forename: Stephen
authors.initials: S
authors.lastname: Forman
authors.forename: Sumanta
authors.initials: S
authors.lastname: Pal
authors.forename: Ravi
authors.initials: R
authors.lastname: Bhatia
authors.forename: Andrew
authors.initials: A
authors.lastname: Raubitschek
authors.forename: Hua
authors.initials: H
authors.lastname: Yu
authors.forename: Marcin
authors.initials: M
authors.lastname: Kortylewski
mesh_terms: D000818:Animals; D045744:Cell Line, Tumor; D018014:Gene Transfer Techniques; D015316:Genetic Therapy / Q000379:methods*; D019337:Hematologic Neoplasms / Q000235:genetics / Q000628:therapy*; D006412:Hematopoietic Stem Cells / Q000473:pathology / Q000502:physiology*; D006801:Humans; D015470:Leukemia, Myeloid, Acute / Q000235:genetics / Q000628:therapy; D008223:Lymphoma / Q000235:genetics / Q000628:therapy; D051379:Mice; D008807:Mice, Inbred BALB C; D016688:Mice, Inbred NOD; D018345:Mice, Knockout; D016513:Mice, SCID; D009101:Multiple Myeloma / Q000235:genetics / Q000628:therapy; D009368:Neoplasm Transplantation; D009838:Oligodeoxyribonucleotides / Q000235:genetics; D034741:RNA, Small Interfering / Q000235:genetics / Q000493:pharmacokinetics*; D011878:Radiotherapy; D050796:STAT3 Transcription Factor / Q000235:genetics; D051217:Toll-Like Receptor 9 / Q000235:genetics* / Q000378:metabolism; D014183:Transplantation, Heterologous
chemical_list: C408982:CPG-oligonucleotide; D009838:Oligodeoxyribonucleotides; D034741:RNA, Small Interfering; D050796:STAT3 Transcription Factor; C494086:STAT3 protein, human; C495371:TLR9 protein, human; D051217:Toll-Like Receptor 9