1-2-dielaidoylphosphatidylethanolamine and Prostatic-Neoplasms

The present study was designed to demonstrate the therapeutic efficacy of a novel immunomodulatory oligonucleotide (IMO) for prostate cancer.. We evaluated the effects of the IMO in xenograft (PC-3) and syngeneic (TRAMP C1) models of prostate cancer, and in prostate cancer cells. The IMO was also evaluated in combination with chemotherapy, and the in vitro expression of TLR9 was examined.. The IMO had significant anti-tumor activity in both prostate cancer models and almost complete tumor regression was observed when the IMO was combined with taxotere or gemcitabine. TLR9 mRNA and protein were both expressed in prostate cancer cells. The IMO also induced apoptosis and decreased proliferation and survival of PC-3 cells in vitro in the presence of Lipofectin.. The IMO inhibits prostate cancer growth in vivo and in vitro, and potentiates the effects of conventional chemotherapeutic agents. This is the first report of TLR9 expression in prostate cancer cells.

Topics: Adenocarcinoma; Animals; Antineoplastic Combined Chemotherapy Protocols; Apoptosis; Cell Line, Tumor; Cell Proliferation; Cell Survival; Deoxycytidine; Docetaxel; Dose-Response Relationship, Drug; Drug Screening Assays, Antitumor; Gemcitabine; Humans; Immunologic Factors; Male; Mice; Mice, Inbred C57BL; Mice, Nude; Neoplasm Transplantation; Oligonucleotides; Phosphatidylethanolamines; Prostatic Neoplasms; RNA, Messenger; Taxoids; Toll-Like Receptor 9

Antisense oligonucleotides (oligos) directed against mRNA-encoding transforming growth factor-alpha (TGF-alpha) and the epidermal growth factor receptor (EGFR) have demonstrated in vitro and in vivo efficacy against prostate cancer tumor models. However, many therapeutic agents have increased effectiveness when given in combination with other more established agents. We evaluated the effectiveness of two oligos (3.32 and 6.64 microM/L) known to have significant activity against the PC-3 prostate cell line in combination therapy with the chemotherapeutic agent paclitaxel (Taxol) (2.5 and 5.0 nm). Therapy was evaluated when oligos and Taxol were administered either as (1) single agents, (2) simultaneously in a combined therapy, or (3) sequentially, a form of combination therapy with both agents being administered in a series. We found that when either of the two oligos were given simultaneously with Taxol, no synergistic activity was noted. However, when sequentially administered in a series 1 d apart, a pretreatment with the antisense directed against TGF-alpha (6.64 microM/L) followed by Taxol (5 nm) had significantly greater activity than these agents similarly administered in the reverse order or simultaneously.>

Topics: Antineoplastic Agents, Phytogenic; Antineoplastic Combined Chemotherapy Protocols; Combined Modality Therapy; Dose-Response Relationship, Drug; Drug Administration Schedule; Drug Synergism; ErbB Receptors; Gene Expression Regulation, Neoplastic; Humans; Male; Oligonucleotides, Antisense; Paclitaxel; Phosphatidylethanolamines; Prostatic Neoplasms; RNA, Neoplasm; Transforming Growth Factor alpha; Tumor Cells, Cultured

Biotinylation is a common modification made to pharmaceuticals, including antisense oligonucleotides (oligos), to enhance their specific delivery. Such agents bind to targets that have been previously labeled with conjugated avidin, or alternatively, heteroconjugate monoclonal antibodies that have dual biotin and tumor-specific antigen specificities may be employed. However, for a drug to be efficacious it must also be taken up by the targeted cells. This is frequently difficult for large molecular weight compounds and cationic lipids, like lipofectin, are often employed. However, the effect of biotinylation on oligo uptake has not been examined in the presence of lipofectin, particularly in prostate cancer cells. Oligos conjugated with biotin and FITC were incubated in vitro with LNCaP and PC-3 cells in the presence of a previously determined effective concentration of lipofectin. Fluorescent uptake and distribution was compared to similar oligos that were not biotinylated. The results demonstrate that biotinylation does not alter the uptake of oligos in LNCaP or PC-3 prostate cancer cells, nor does it alter their retention or cytoplasmic distribution in PC-3 cells when used with lipofectin.

Topics: Biotinylation; Humans; Male; Oligonucleotides, Antisense; Phosphatidylethanolamines; Prostatic Neoplasms; Tumor Cells, Cultured

Lipofectin, the commercially available cationic liposome, was used to introduce the purified prostatic acid phosphatase protein into the established human prostate carcinoma cells. The incorporated phosphatase protein which retained its enzymatic activity as demonstrated by the tartrate-sensitive acid phosphatase assay was localized in the cytoplasm by immunofluorescence staining. Further, cells that were treated with phosphatase/Lipofectin complexes expressed a decreased phosphotyrosine level, presumably due to the endogenous protein tyrosine phosphatase activity of the acid phosphatase protein. A cationic liposome such as lipofectin may thus be employed to mediate transport of other acidic proteins into cells, providing a way to examine their biological functions in vivo.

Topics: Acid Phosphatase; Cations; Fluorescent Antibody Technique; Humans; Male; Phosphatidylethanolamines; Phosphotyrosine; Prostatic Neoplasms; Time Factors; Transfection; Tumor Cells, Cultured; Tyrosine