Frequent mutations in the mitochondrial control region DNA in breast tissue.

It has been suggested that the extent of mitochondrial DNA mutations might be useful in the prognosis of cancer outcome and/or the response to certain therapies. In order to investigate whether a high incidence of mutations exists in mitochondrial DNA of breast cancer tissues, we screened three regions of the mitochondrial genome by PCR amplification followed by DNA sequence analysis. Laser capture microdissection was used to isolate pure populations of both tumor cells and normal cells from paraffin embedded specimens.

12-O-tetradecanoylphorbol-13-acetate induces apoptosis in renal epithelial cells through a growth signal conflict which is prevented by activated ras.

12-O-Tetradecanoylphorbol-13-acetate (TPA) induced apoptosis in the pig renal epithelial cell line LLC-PK1 after 24 h of treatment as assessed by caspase 3 activation. Cotreatment of the cells with bryostatin markedly reduced the apoptotic effects of TPA. Okadaic acid, another tumor promoter, also induced apoptosis.

Functional analysis of human ornithine decarboxylase alleles.

It has been known for > 10 years that there are two alleles of the human ornithine decarboxylase (ODC) gene, defined by a polymorphic PstI RFLP in intron 1. We have sequenced a large portion of each of the two alleles, including some of the 5' promoter region, exon 1, intron 1, and exon 2, and determined that a single nucleotide polymorphism at base +317 (relative to transcription start site) is responsible for the presence or absence of the PstI restriction site. We have developed two genotyping assays, a PCR-RFLP assay and a high-throughput TaqMan-based method, and determined the ODC genotype distribution in >900 North American DNA samples.

Overexpression of protein kinase C-delta increases tight junction permeability in LLC-PK1 epithelia.

The Ca2+-independent delta-isoform of protein kinase C (PKC-delta) was overexpressed in LLC-PK1 epithelia and placed under control of a tetracycline-responsive expression system. In the absence of tetracycline, the exogenous PKC-delta is expressed. Western immunoblots show that the overexpressed PKC-delta is found in the cytosolic, membrane-associated, and Triton-insoluble fractions.

AP-1 activity affects the levels of induced erythroid and megakaryocytic differentiation of K562 cells.

The effect of modulating AP-1 activity on the levels of induced erythroid and megakaryocytic differentiation of the erythroleukemia cell line K562 was examined. Cells were stably transfected with expression vectors encoding either a tetracycline-responsive dominant negative c-Jun (JunDN) or a hybrid Raf protein inducible by estrogen. Down-regulation of AP-1 activity by induction of JunDN enhanced erythroid differentiation by two agents, cytosine arabinoside and activin A.