Estrogen mitogenic action. I. Demonstration of estrogen-dependent MTW9/PL2 carcinogen-induced rat mammary tumor cell growth in serum-supplemented culture and technical implications

Jorge E. Moreno-Cuevas, David A. Sirbasku*

*Corresponding author for this work

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6 Citations (Scopus)


The MTW9/PL cell line was established by our laboratory in culture from the carcinogen-induced hormone-responsive MT-W9A rat mammary tumor of a Wistar-Furth (W/Fu) rat. This tumor formed estrogen, androgen, and progesterone responsive tumors in W/Fu rats (Sirbasku, D. A., Cancer Res. 38:1154-1165; 1978). It was later used to derive the MTW9/PL2 cell population which was also estrogen-responsive in vivo (Danielpour, D., et al., In Vitro Cell. Dev. Biol. 24:42-52; 1988). In the study presented here, we describe serum-supplemented culture conditions in which the MTW9/PL2 cells demonstrate ≥80-fold steroid hormone growth responses. All sera used were steroid hormone-depleted by charcoal-dextran treatment at 34°C. The studies were done with horse serum as well as serum from other mammalian species. The growth of the MTW9/PL2 cells was biphasic in response to hormone-depleted serum. Concentrations of ≤5% (v/v) promoted optimum growth. Above this concentration, serum was inhibitory. Concentrations ≥40% (v/v) inhibited growth altogether. Addition of 1.0 x 10-13-1.0 x 10-8 M 17β-estradiol (E2) reversed the inhibition completely. At 1.0 x 10-8 M, estrone, estriol and diethylstilbestrol promoted growth as well as E2. Testosterone and dihydrotestosterone promoted growth only at ≥10-7 M. Progesterone was effective only at ≥10-6 M. Cortisol was ineffective. Labeled-hormone-binding analysis and Western immunoblotting documented that MTW9/PL2 cells had estrogen and progesterone receptors but not androgen or cortisol receptors. Estrogen treatment of MTW9/PL2 cells induced a concentration and time dependent increase in progesterone receptors. We conclude (1) the MTW9/PL2 population is the first highly steroid hormone-responsive rat mammary tumor cell line to be established in culture from a carcinogen-induced tumor, and (2) sera from a number of species including horse, rat and human contain an inhibitor which mediates estrogen sensitive MTW9/PL2 cell growth in culture.

Original languageEnglish
Pages (from-to)410-427
Number of pages18
JournalIn Vitro Cellular and Developmental Biology - Animal
Issue number7
Publication statusPublished - 1 Jan 2000
Externally publishedYes

Bibliographical note

Funding Information:
We gratefully acknowledge the many helpful comments of our former colleagues Dr. Hidetaka Sato and Dr. John E. Eby and the earlier technical efforts of Ms. Judy Roscoe to develop an effective charcoal extraction method. This research was supported by grants DAMD17-94-J-4473, DAMD17-98-1-8337, and DAMD17-99-1-9405 from the Defense Department, US A,any Medical Research and Materiel Command, Breast Cancer Research Program, a grant-in-aid from the Cancer Federation, Banning, California, grants-in-aid from the Women's Fund for Health Education and Research, Houston, Texas, and a grant-in-aid from the Houston Texas Chapter of the Susan G. Komen Breast Cancer Foundation.

Copyright 2017 Elsevier B.V., All rights reserved.

All Science Journal Classification (ASJC) codes

  • Developmental Biology
  • Cell Biology


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