Panagiotou S, Hatzoglou A, Calvo F, Martin PM, Castanas E. Modulation of the estrogen-regulated proteins cathepsin D and pS2 by opioid agonists in hormone-sensitive breast cancer cell lines (MCF7 and T47D): evidence for an interaction between the two systems.
J Cell Biochem 1998;
71:416-28. [PMID:
9831078 DOI:
10.1002/(sici)1097-4644(19981201)71:3<416::aid-jcb10>3.0.co;2-y]
[Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
In many cancer cell lines, including breast, prostate, lung, brain, head and neck, retina, and the gastrointestinal tract, opioids decrease cell proliferation in a dose-dependent and reversible manner. Opioid and/or other neuropeptide receptors mediate this decrease. We report that only the steroid-hormone-sensitive cell lines MCF7 and T47D respond to opioid growth inhibition in a dose-dependent manner. Therefore, an interaction of the opioid and steroid receptor system might exist, as is the case with insulin. To investigate this interaction, we have assayed two estrogen-inducible proteins (pS2 and the lysosomal enzyme cathepsin D) in MCF7 and T47D cells. When cells were grown in the presence of FBS (in which case a minimal quantity of estrogens and/or opioids is provided by the serum), we observed either no effect of etorphine or ethylketocyclazocine (EKC) or an increase of secretion and/or production of pS2 and cathepsin D. However, when cells were cultured in charcoal-stripped serum and in the absence of phenol red, the effect of the two opioids is different: EKC decreased the production and/or secretion of pS2 and cathepsin D, whereas etorphine increased their synthesis and/or secretion. The differential effect of the two general opioids was attributed to their different receptor selectivity. Furthermore, the variations of the ratio of secreted/produced protein and the use of cycloheximide indicate that opioids selectively modify the regulatory pathway of each protein discretely. In conclusion, through the interaction with opioid and perhaps other membrane-receptor sites, opioid agonists modify in a dose-dependent manner the production and the secretion of two estrogen-regulated proteins. Opioids may therefore disturb hormonal signals mediated by the estrogen receptors. Hence, these chemicals may have potential endocrine disrupting activities.
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