Purpose: Epigenetic silencing via aberrant promoter DNA hypermethylation of normal genes has been described as a leukemogenic mechanism in myelodysplastic syndromes (MDS) and acute myeloid leukemias (AML). We hypothesized that MG98, an oligonucleotide antisense to DNA methyltransferase 1 (DNMT1), could reverse malignant phenotypes by down-regulating DNMT1 and inducing reexpression of hypermethylated genes. This phase I study was conducted to determine a biologically effective dose and describe the safety of MG98 in MDS/AML.
View Article and Find Full Text PDFUveal melanoma (UM) is a highly malignant primary intraocular tumour in adults that has a high mortality rate due to haematogenous dissemination. The migration of UM cells through the basement membrane requires the presence of proteolytic enzymes, such as matrix metalloproteinases (MMPs). The expression of MMP-2, MMP-9 and membrane type-1/MMP (MT-1/MMP) in UM cells is a known risk factor for metastatic disease.
View Article and Find Full Text PDFPurposes: Pharmacologic downregulation of Bcl-2, an antiapoptotic protein overexpressed in cancer, might increase chemosensitivity in acute myeloid leukemia (AML). Herein, we investigated the feasibility of this approach in untreated elderly AML patients by administering oblimersen sodium (G3139), an 18-mer phosphorothioate antisense to Bcl-2, during induction and consolidation treatments.
Patients And Methods: Untreated patients with primary or secondary AML (stratified to cohort 1 or 2, respectively) who were > or = 60 years received induction with G3139, cytarabine, and daunorubicin at one of two different dose levels (45 and 60 mg/m2) and, on achievement of complete remission (CR), consolidation with G3139 and high-dose cytarabine.
MLL (ALL-1) chimeric fusions and MLL partial tandem duplications (PTD) may have mechanistically distinct contributions to leukemogenesis. Acute myeloid leukemia (AML) blasts with the t(9;11)(p22; q23) express MLL-AF9 and MLL wild-type (WT) transcripts, while normal karyotype AML blasts with the MLL(PTD/WT) genotype express MLL PTD but not the MLL WT. Silencing of MLL WT in MLL(PTD/WT) blasts was reversed by DNA methyltransferase (DNMT) and histone deacetylase (HDAC) inhibitors, and MLL WT induction was associated with selective sensitivity to cell death.
View Article and Find Full Text PDFThe translocation t(8;21)(q22;q22) in acute myeloid leukemia (AML) results in the expression of the fusion protein RUNX1/MTG8, which in turn recruits histone deacetylases (HDAC) to silence RUNX1 target genes [e.g., interleukin-3 (IL-3)].
View Article and Find Full Text PDFThe post-translational modification of the core histones is critical to the regulation of chromatin structure. Traditional methods for the determination of histone modification utilize immunoassay techniques to determine the extent and site of post-translational modification. These methods, though sensitive, require site-specific antibodies.
View Article and Find Full Text PDFPurpose: Uveal melanoma (UM) is the most common primary malignant ocular tumor in adults. No effective chemotherapy regimens are available for either intraocular or metastatic uveal melanoma. Therefore, the ability of the histone deacetylase inhibitors (HDACIs), depsipeptide, sodium butyrate (NaB) and trichostatin A (TSA), to induce apoptosis and inhibit cell growth of UM cell lines in vitro was examined.
View Article and Find Full Text PDFOverexpression of Bcl-2 is a potential mechanism for chemoresistance in acute leukemia and has been associated with unfavorable clinical outcome. We hypothesized that down-regulation of Bcl-2 would restore chemosensitivity in leukemic cells. To test this hypothesis, we performed a phase 1 study of G3139 (Genasense, Genta, Berkeley Heights, NJ), an 18-mer phosphorothioate Bcl-2 antisense, with fludarabine (FL), cytarabine (ARA-C), and granulocyte colony-stimulating factor (G-CSF) (FLAG) salvage chemotherapy in patients with refractory or relapsed acute leukemia.
View Article and Find Full Text PDF