The cellular origin of prostaglandins in human tumors was investigated using cell fractionation procedures and high resolution gas chromatography. Additionally, the role of macrophages and prostaglandins on human tumor cloning in vitro was investigated. Spontaneous human tumors were prepared as single cell suspensions which were subsequently manipulated to yield macrophage-enriched, and tumor cell enriched (macrophage-depleted) subpopulations of cells. A fused silica capillary gas chromatographic analysis with electron capture detection was developed to measure derivatized prostaglandins in the supernatant of the cell subpopulation incubations. The derivative used for the analysis was the pentafluorobenzyl ester-methoxime-trimethyl-silyl ether. The assay showed a detection limit of 25 picograms of prostaglandins E₁, E₂, F₂ₐ, and I₂ (which was detected as 6-Keto-PGF₁ₐ). Analysis of cell subpopulations of seventeeen tumor samples showed that the macrophage-enriched cells were responsible for the large majority of prostaglandin production in vitro (p ≤ 0.02). It was found that the major prostaglandins were PGE₂ and PGI₂. The range of values measured for macrophage produced prostaglandin E₂ was 1.1 to 704.8 ng/ml after a 24 hour incubation of 10⁶ cells. Prostaglandin I₂ was also produced by the macrophage-enriched cell subpopulation with values ranging from 1.2 to 334.3 ng/ml. This is the first report of prostaglandin I₂ production by host macrophages infiltrating human tumors. Studies of the effect of macrophage depletion and reconstitution on the ability of tumor cells to form colonies in vitro were performed. A two layer soft agar assay was used to evaluate tumor cells clonogenicity. The results demonstrated that macrophages infiltrating human carcinoma samples function in a supportive role for tumor cell colony formation in vitro. Using a prostaglandin synthesis inhibitor, flurbiprofen, it was shown that this support was not the result of a direct effect of prostaglandins on the tumor cells. Possible roles for macrophage produced prostaglandins in cancer are discussed.
| Identifer | oai:union.ndltd.org:arizona.edu/oai:arizona.openrepository.com:10150/184348 |
| Date | January 1982 |
| Creators | BERENS, MICHAEL EDWARD. |
| Publisher | The University of Arizona. |
| Source Sets | University of Arizona |
| Language | English |
| Detected Language | English |
| Type | text, Dissertation-Reproduction (electronic) |
| Rights | Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author. |
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