The co-induction of sister chromatid exchanges and virus synthesis in mammalian cells.
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Biomedical subjects
Publications and source records attributed to C Dougherty.
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We have previously reported on two patients with acute promyelocytic leukemia (APL) who had what appeared to be a deletion of chromosome No. 17. We now describe a third patient with APL. All three patients had a structural rearrangement involving No. 15 and No. 17. Our current interpretation of the chromosomal abnormality is that it is a reciprocal translocation, t (15;17) (q22; q21). Evidence that this is a consistent rearrangement associated with APL comes not only from our three patients, but also from two other published cases of APL, studied with banding, who also had an identical abnormality.
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Cultured human breast epithelial cells from reduction mammoplasty specimens were transduced using an adeno-associated virus vector encoding the marker gene E. coli -galactosidase. Subconfluent, growing, breast epithelial cells were more easily transduced than confluent, quiescent, cells. Transduction of non-dividing confluent cells could be greatly increased by ultraviolet light-induced DNA damage or by prior exposure to the DNA synthesis inhibitor hydroxyurea. The effects of ultraviolet light and hydroxyurea on transduction were additive when these agents were applied together.
The estrogen and progesterone receptor expression was determined in breast epithelial cells from reduction mammoplasty specimens. Only a subset of the luminal epithelial cell population was found to be positive for these receptors. When these cells were subsequently cultured in 3-dimensional collagen gel system (in vitro model) or transplanted into nude mice (in vivo model), the cells retained their ability to express both receptors in these experimental systems. The maintenance of primary normal human breast epithelial cells expressing the estrogen and progesterone receptors in experimental systems has not been reported previously.
Human tumor xenografts in nude mice are widely utilized model system for the transplantation of human surgical specimens and human established cell lines. Gene expression studies are often carried out in these model systems. With an increasing use of PCR based analyses, the extreme sensitivity of this technique poses a serious challenge with regards to the extent of contaminating host mouse cells in the human tumor xenografts. These xenografts are never free of host cell contamination. We detected mouse estrogen receptor expression in several human tumor xenografts using RT-PCR demonstrating that precaution is necessary when utilizing PCR based analyses in human tumor xenografts. A cytologically based methodology which distinguishes human versus mouse cells will be more suitable for ER expression studies using human xenograft models. Both (1) in situ hybridization using human probe and (2) immunocytochemistry using a monoclonal antibody directed against human cytokeratin have been used successfully to distinguish human cells versus host mouse cells in human xenografts in nude mice. Immunostaining of ER can then be utilized to determine the expression pattern of ER in the transplanted human cells.