1-2-oleoylphosphatidylcholine and Carcinoma

We investigated the clinical and biological significance of p130cas, an important cell signaling molecule, in ovarian carcinoma.. Expression of p130cas in ovarian tumors, as assessed by immunohistochemistry, was associated with tumor characteristics and patient survival. The effects of p130cas gene silencing with small interfering RNAs incorporated into neutral nanoliposomes (siRNA-DOPC), alone and in combination with docetaxel, on in vivo tumor growth and on tumor cell proliferation (proliferating cell nuclear antigen) and apoptosis (terminal deoxynucleotidyl transferase dUTP nick-end labeling) were examined in mice bearing orthotopic taxane-sensitive (HeyA8 and SKOV3ip1) or taxane-resistant (HeyA8-MDR) ovarian tumors (n = 10 per group). To determine the specific mechanisms by which p130cas gene silencing abrogates tumor growth, we measured cell viability (MTT assay), apoptosis (fluorescence-activated cell sorting), autophagy (immunoblotting, fluorescence, and transmission electron microscopy), and cell signaling (immunoblotting) in vitro. All statistical tests were two-sided.. Of 91 ovarian cancer specimens, 70 (76%) had high p130cas expression; and 21 (24%) had low p130cas expression. High p130cas expression was associated with advanced tumor stage (P < .001) and higher residual disease (>1 cm) following primary cytoreduction surgery (P = .007) and inversely associated with overall survival and progression-free survival (median overall survival: high p130cas expression vs low expression, 2.14 vs 9.1 years, difference = 6.96 years, 95% confidence interval = 1.69 to 9.48 years, P < .001; median progression-free survival: high p130cas expression vs low expression, 1.04 vs 2.13 years, difference = 1.09 years, 95% confidence interval = 0.47 to 2.60 years, P = .01). In mice bearing orthotopically implanted HeyA8 or SKOV3ip1 ovarian tumors, treatment with p130cas siRNA-DOPC in combination with docetaxel chemotherapy resulted in the greatest reduction in tumor growth compared with control siRNA therapy (92%-95% reduction in tumor growth; P < .001 for all). Compared with control siRNA therapy, p130cas siRNA-DOPC reduced SKOV3ip1 cell proliferation (31% reduction, P < .001) and increased apoptosis (143% increase, P < .001) in vivo. Increased tumor cell apoptosis may have persisted despite pan-caspase inhibition by the induction of autophagy and related signaling pathways.. Increased p130cas expression is associated with poor clinical outcome in human ovarian carcinoma, and p130cas gene silencing decreases tumor growth through stimulation of apoptotic and autophagic cell death.

Topics: Adult; Aged; Animals; Antineoplastic Combined Chemotherapy Protocols; Apoptosis; Apoptosis Regulatory Proteins; Autophagy; Beclin-1; Carcinoma; Cell Survival; Crk-Associated Substrate Protein; Disease-Free Survival; Docetaxel; Down-Regulation; Electrophoresis, Polyacrylamide Gel; Female; Fluorescent Antibody Technique; Gene Expression Regulation, Neoplastic; Gene Silencing; Green Fluorescent Proteins; Humans; Immunoblotting; Immunohistochemistry; Kaplan-Meier Estimate; Membrane Proteins; Mice; Microscopy, Electron, Transmission; Microtubule-Associated Proteins; Middle Aged; Multivariate Analysis; Ovarian Neoplasms; Phosphatidylcholines; Phosphatidylinositol 3-Kinases; Proto-Oncogene Proteins c-akt; RNA, Small Interfering; Signal Transduction; Taxoids; Transfection; Transplantation, Heterologous; Up-Regulation

Discovery of RNA interference (RNAi) has been one of the most important findings in the last ten years. In recent years, small interfering RNA (siRNA)-mediated gene silencing is beginning to show substantial promise as a new treatment modality in preclinical studies because of its robust gene selective silencing. However, until recently, delivery of siRNA in vivo was a major impediment to its use as a therapeutic modality. We have used a neutral liposome, 1,2-dioleoyl-sn-glycero-3-phosphatidylcholine (DOPC), for highly efficient in vivo siRNA delivery. Using siRNA tagged with Alexa-555, incorporated in DOPC liposomes, we have demonstrated efficient intra-tumoral delivery following either intraperitoneal or intravenous injection. Furthermore, EphA2-targeted siRNA in DOPC liposomes showed significant target modulation and anti-tumor efficacy.

Topics: Animals; Carcinoma; Female; Fluorescent Dyes; Gene Silencing; Genetic Therapy; Humans; Liposomes; Mice; Mice, Nude; Ovarian Neoplasms; Phosphatidylcholines; Receptor, EphA2; RNA, Small Interfering