In vivo immune stimulation assays. For efficacy studies, defined humane end points were determined as a surrogate for survival. Kaplan-Meier plot of days to euthanization due to tumor burden. Cowan has authored more than papers for scientific journals and has been appointed by President Bush to a six-year term on the National Cancer Advisory Board to help shape cancer policy.
Here, we describe the preclinical development of chemically modified siRNA targeting the essential cell-cycle proteins polo-like kinase 1 PLK1 and kinesin spindle protein KSP in mice. These types of response are known to elicit antitumor effects, primarily through the actions of IFNs and inflammatory cytokines that exert antiangiogenic, proapoptotic, and adjuvant effects that enhance cellular immunity 78.
Positive cells included aberrant and typical mitotic and apoptotic figures. To expand the general utility of this technology in oncology, we determined whether the performance of this liver-targeting SNALP formulation 26 could be further improved for delivering siRNA to tumors outside of the liver.
The specificity and mechanism of action is confirmed using a combination of methodologies that demonstrate RNAi-mediated silencing of target mRNA causing mitotic disruption in tumor cells typical of target inhibition.
No tumor, livers from non—tumor-seeded mice. Dose-dependent inhibition of tumor growth was evident from 0. Taken together, this battery of tests provided conclusive evidence that the potent therapeutic effects of these SNALP-formulated siRNAs in the absence of a measurable immune response are the result of RNAi.
To date there are several clinical trials using RNAi, and we should expect the list of new applications to grow at a phenomenal rate.
There was also no induction of the IFN inducible gene IFIT1 either in the liver, representing the primary target organ for these delivery vehicles, or within secondary lymphoid tissues.
Bertino served as director of the Yale Comprehensive Cancer Center, including director of the center and associate director for clinical research.
For the last 20 years, Dr.
Baylin is professor of oncology and medicine, director of the cancer biology program at the oncology center, and the Virginia and D. Therefore, the maintenance of drug activity for an siRNA therapeutic is uncoupled from the requirement to maintain an effective drug concentration in the blood.
Induction of the innate immune response by nucleic acids can also have significant toxicologic consequences reviewed in ref. Hepatic Neuro2a tumor histology 24 hours after a single i.
It should be noted that this siRNA design is based on blunt-ended mer duplexes that, as naked molecules, are predicted not to activate TLR3 4. In vitro immune stimulation assays. Baylin has studied the role of epigenetic gene silencing in the initiation and progression of human cancer.
Common approaches to delivery include complexing the siRNA with polycations such as polyethyleneimine 2930 and cyclodextrin polymers 31 as well as incorporation into cationic lipid—based carriers 171826 This suggests that active RNAi continued to occur either within a subset of tumor cells at subcytotoxic levels or within an initially nonproliferative population that subsequently entered cell cycle and reexpressed PLK1 mRNA.
PLK1 represents a validated gene target in oncology whose inhibition is known to cause mitotic arrest and apoptosis in proliferating tumor-cell cultures This involved a combination of approaches: Figure 6 Duration of RNAi activity within hepatic tumors.
One of the primary barriers to realizing the potential of siRNA therapeutics is the requirement for drug-delivery vehicles to facilitate disease site targeting, cellular uptake, and cytoplasmic delivery of the siRNA 26 — For vehicles containing poly ethylene glycol-conjugated lipids PEG-lipids such as SNALP, increased blood residency time and tumor accumulation can be achieved by incorporating PEG-lipids with longer alkyl chains that associate more strongly with the lipid particle and provide greater shielding in the blood compartment This remains a valid concern for the burgeoning field of siRNA-based therapeutics See Supplemental Figure 6 for additional data.
Unlike other chemical modification strategies for siRNAs, enhancing nuclease resistance was not a primary design consideration, since SNALP, the intended delivery vehicle for in vivo studies, is known to protect unmodified siRNA from nuclease degradation for more than 24 hours in serum For the in vivo efficacy of siRNA molecules, the dosage of delivered siRNAs is a practical consideration, and selective delivery of siRNAs to specific tissues would potentially lower the effective dosage required.
The genomic landscape of schwannoma is complex and many of the molecules implicated in VS pathogenesis represent targets not amenable to antibody-based or small molecule therapeutics.
Tumor-targeted delivery of small interfering RNA (siRNA. RNA interference (RNAi) is an evolutionary regulatory mechanism of most cells that uses ∼21–25 long siRNA transcripts to effectively control the expression of desired genes.
By inhibiting the expression of mRNA transcripts through degrading or binding sequence specifically thus hindering translation into proteins.
Research Paper Multi-target siRNA: Therapeutic Strategy for Hepatocellular Carcinoma of each siRNA was evaluated by relative luciferase activity unit (RLU). All experiments were performed in triplicates and repeated three times.
Journal of CancerVol. 7. Mar 30, · I am doing siRNA transfection using RNAiMAX. i am doing it in 10cm plates. i am not sure about the ratio of RNAiMAX and siRNA to be added per plate. The concentration of siRNA. Mar 30, · Explore the latest articles, projects, and questions and answers in Gene Silencing by siRNA, and find Gene Silencing by siRNA experts.Download