as-1411 and Leukemia--Myeloid--Acute

In development by Antisoma plc, AS-1411 is the first oligodeoxynucleotide aptamer to reach phase I and II clinical trials for the potential treatment of cancers, including acute myelogenous leukemia (AML). As an aptamer, AS-1411 does not appear to engage in hybridization-requiring pathways such as antisense effect, siRNA or triple helix formation. Instead, AS-1411 appears to bind to nucleolin specifically, and is subsequently internalized into the tumor cell. Nucleolin is an abundant protein, with expression that is correlated with the proliferative status of the cell: nucleolin levels are higher in tumors and actively dividing cells. Because of the multifunctional nature of nucleolin, it is probable that many secondary targets are affected following treatment with AS-1411. AS-1411 has demonstrated preclinical growth inhibition activity against a wide variety of tumor cell lines at concentrations in the micromolar range, and resulted in good efficacy in mice xenografted with tumor cells of human origin. In a phase I clinical trial in patients with advanced, refractory cancers with metastases at multiple sites, AS-1411 was safe and well tolerated; in addition, one complete response and one ongoing partial response were reported in two patients with renal cell carcinoma. A phase II trial of AS-1411 in combination with cytarabine in patients with AML demonstrated the combination to be superior to cytarabine alone. Thus, AS-1411 appears to be a promising candidate for cancer treatment in these pathologies. A greater understanding of the mechanism of action of this agent is essential to aid in future research.

Topics: Antineoplastic Agents; Aptamers, Nucleotide; Clinical Trials as Topic; Humans; Leukemia, Myeloid, Acute; Neoplasms; Nucleolin; Oligodeoxyribonucleotides; Phosphoproteins; RNA-Binding Proteins

Leukemia remains a fatal disease for most patients and novel therapeutic strategies are urgently needed. Aberrant DNA methylation is an epigenetic modification that is important in the initiation and progression of leukemia. Here, we demonstrated NCL/miR-221/NFκB/DNMT1 axis as a new molecular pathway promoting aggressive acute myeloid leukemia (AML) leukemogenesis and successfully designed and prepared a nuclear localization signal (NLS) peptide-targeted gold nanoparticles with co-loaded anti-221 and AS1411 (NPsN-AS1411/a221), which can specifically target NCL/miR-221/NFκB/DNMT1 signaling pathway in AML. NPsN-AS1411/a221 synergistically abrogate endogenous miR-221 promoting cancerous growth by inhibiting the expression of p27Kip1 suppressor gene, as well as effectively deregulate the DNMT1 expression through NFκB signaling which led to a reduction of global DNA methylation and the restoration of tumor suppressor p15INK4B via its promoter DNA hypomethylation. Functionally, NPsN-AS1411/a221 remarkably blockage leukemia proliferation and clonogenic potential in NCL/miR-221/NFκB/DNMT1 positive AML cell lines. More importantly, NPsN-AS1411/a221 cooperatively extend the overall survival, lower the white blood cells, reverse splenomegaly, inhibit blasts in bone marrow and metastatic to lung in a preclinical AML animal model. Altogether, our studies provide a proof of concept for multiple-functional drug delivery system that based on the specific gene network involved in tumor growth, and highlight the clinical potential of NCL/miR-221/NFκB/DNMT1-targeted AML nanotherapy.

Topics: Animals; Antagomirs; Aptamers, Nucleotide; Cell Line, Tumor; DNA Methylation; Drug Carriers; Epigenesis, Genetic; Genetic Therapy; Gold; Humans; Leukemia, Myeloid, Acute; Male; Metal Nanoparticles; Mice, Inbred C57BL; MicroRNAs; Nuclear Localization Signals; Oligodeoxyribonucleotides

AS1411 is a DNA aptamer that is in phase II clinical trials for relapsed or refractory acute myeloid leukemia and for renal cell carcinoma. AS1411 binds to nucleolin, a protein that is overexpressed in the cytoplasm and on the plasma membrane of some tumor cells compared with normal cells. Studies were performed to determine whether cell surface nucleolin is a receptor for AS1411 in the acute myeloid leukemia cell line MV4-11. Biotinylation of MV4-11 cell surface proteins followed by immunoblotting of the biotinylated proteins showed that full-length (106 kDa) and truncated forms of nucleolin were present on the cell surface. In contrast, K-562 cells, which are 4-fold less sensitive than MV4-11 cells to AS1411, showed no full-length nucleolin and lesser amounts of the truncated forms of nucleolin on the cell surface. Incubation of MV4-11 cells with [(32)P]AS1411 and immunoprecipitation of the plasma membrane fraction with anti-nucleolin antibody demonstrated the presence of [(32)P]AS1411-nucleolin complexes. Anti-nucleolin antibody inhibited binding of fluorescein isothiocyanate (FITC)-AS1411 to plasma membrane nucleolin 56 +/- 10% SE (P < 0.01) compared with cells incubated with FITC-AS1411 only. Cellular uptake of [(32)P]AS1411 into MV4-11 cells was blocked by a 20-fold excess of unlabeled AS1411 but not by a 20-fold excess of the biologically inactive oligonucleotide CRO-26. Uptake was approximately 3-fold faster into MV4-11 cells than into K-562 cells. Partial knockdown of plasma membrane and cytosolic nucleolin in MCF-7 cells resulted in a 3-fold decrease in AS1411 uptake. These results provide evidence that plasma membrane nucleolin is a functional receptor for AS1411 in MV4-11 cells.

Topics: Animals; Antineoplastic Agents; Aptamers, Nucleotide; Cell Line, Tumor; Humans; K562 Cells; Leukemia, Myeloid, Acute; Membrane Proteins; Mice; Nucleolin; Oligodeoxyribonucleotides; Phosphoproteins; Protein Binding; Receptors, Cell Surface; RNA-Binding Proteins