ABSTRACT
The eukaryotic translation initiation factor 4E (eIF4E) is a potent oncogene that is found to be dysregulated in 30% of human cancer, including colorectal carcinogenesis (CRC). ISIS 183750 is a second-generation antisense oligonucleotide (ASO) designed to inhibit the production of the eIF4E protein. In preclinical studies we found that EIF4e ASOs reduced expression of EIF4e mRNA and inhibited proliferation of colorectal carcinoma cells. An additive antiproliferative effect was observed in combination with irinotecan. We then performed a clinical trial evaluating this combination in patients with refractory cancer. No dose-limiting toxicities were seen but based on pharmacokinetic data and tolerability the dose of irinotecan was reduced to 160 mg/m(2) biweekly. Efficacy was evaluated in 15 patients with irinotecan-refractory colorectal cancer. The median time of disease control was 22.1 weeks. After ISIS 183750 treatment, peripheral blood levels of eIF4E mRNA were decreased in 13 of 19 patients. Matched pre- and posttreatment tumor biopsies showed decreased eIF4E mRNA levels in five of nine patients. In tumor tissue, the intracellular and stromal presence of ISIS 183750 was detected by IHC in all biopsied patients. Although there were no objective responses stable disease was seen in seven of 15 (47%) patients who were progressing before study entry, six of whom were stable at the time of the week 16 CT scan. We were also able to confirm through mandatory pre- and posttherapy tumor biopsies penetration of the ASO into the site of metastasis.
Subject(s)
Camptothecin/analogs & derivatives , Colorectal Neoplasms/therapy , Eukaryotic Initiation Factor-4E/antagonists & inhibitors , Oligonucleotides, Antisense/therapeutic use , Oligoribonucleotides/therapeutic use , Adult , Aged , Camptothecin/adverse effects , Camptothecin/blood , Camptothecin/therapeutic use , Cell Line, Tumor , Colorectal Neoplasms/drug therapy , Colorectal Neoplasms/genetics , Combined Modality Therapy , Eukaryotic Initiation Factor-4E/genetics , Female , HCT116 Cells , Humans , Irinotecan , Male , Middle Aged , Oligonucleotides , Oligonucleotides, Antisense/genetics , Oligoribonucleotides/genetics , RNA, Messenger/blood , RNA, Messenger/geneticsABSTRACT
The cytoplasm status according to mitochondrial sequence tags was determined in agamospermous sugar beet progenies characterized by unstable manifestation of cytoplasmic male sterility. The detected variations in the ratios of homologous sequences related to the N and S mtDNA types did not correlate with pollen phenotypes of the plants. Polymerase chain reaction allowed semiquantitative evaluation of these variations and their detection. A cDNA corresponding to a hitherto unknown minor RNA and containing a consensus sequence of dicotyledonous plant promoters was detected by mtRNA display. Probable sources of CMS variability in agamospermous sugar beet progenies are discussed.
Subject(s)
Beta vulgaris/genetics , DNA, Mitochondrial/genetics , Genes, Plant/genetics , Genetic Variation , Plant Infertility , Pollen , Gene Expression Profiling , Gene Expression Regulation, Plant/genetics , RNA, Plant/genetics , Reverse Transcriptase Polymerase Chain Reaction/methodsABSTRACT
Several 5'-degenerate primers were selected by computer analysis and used for mtDNA typing in sugar beet cultivars with cytoplasms of the S (typical for cytoplasmic male sterility) or N (normal) type. A number of N- or S-specific markers were found to correspond to transcribed mitochondrial genes. One was from the orf215 region of the N-type mtDNA. A physical map of the corresponding region was constructed for the S-type mtDNA, and a substantial difference observed for the two genome types. One N-specific marker proved to contain a rearranged rps3 region and a truncated atp9 copy. With the known nucleotide sequence of this marker, three-primer PCR was designed and showed that both variants of the rps3 region simultaneously take place in the mtDNA pool, the new one occurring in a substochiometric proportion.