Etienne Y. Lasfargues

A method for the continuous cultivation of mammary epithelium.

SummaryEstablished cell lines of mammary epithelium have been obtained from mice, rats, and hamsters. Maintenance and replication of the epithelium in serial subcultures were dependent on their periodic treatment with collagenase. Because collagenase is not cytotoxic and has maximum efficiency at neutral pH in isotonic saline solutions containing calcium and magnesium, this enzyme can be introduced directly into the culture medium; cells have been maintained for 3 days in such a medium with serous enrichment at no detriment to them. Up to 10% concentrations of serum have not interfered with enzymatic activity.

Hormonal influences on the differentiation and growth of embryonic mouse mammary glands in organ culture

Abstract The action of estradiol, progesterone, growth hormone, mammotropin, and cortisol has been tested on the differentiation and growth of the embryonic mouse mammary gland in organ cultures maintained on a synthetic nutrient. Estradiol and progesterone inhibit the growth of the mammary epithelium. Estradiol stimulates the adipose tissue, and ground substance and connective tissue are eliminated as an effect of progesterone. Growth hormone and mammotropin promote an active growth of the mammary epithelium. However, mammotropin acts more specifically on the adipose tissue. Cortisol conditions the gland for secretion, inducing the distension of ducts to form alveoli and a hyperactivity of the adipose tissue.

A serum substitute that can support the continuous growth of mammary tumor cells

SummaryA substitute for the serum enrichments usually added to commercial, chemically defined tissue culture media was prepared. This serum substitute (SSK) was an aqueous solution, in triple-distilled water, of 10% peptone, 1% dextrose, 5% lactalbumin hydrolysate, and 3.5% polyvinylpyrrolidone K90. The clear solution was sterilized in the autoclave at 10 psi for 20 min. and then used as 10% of the total medium, with insulin-supplemented (0.01 mg per ml) Eagles minimal essential medium for the mouse cells or RPMI-1640 for human cells.Both human and mouse mammary tumor cell lines have shown a net increase of the original seed 7 days after transfer in the SSK medium. Continuous growth in this medium was demonstrated by several subcultures over several, months of cultivation. Human or mouse cell lines derived from normal donors were comparatively tested in the same medium but did not survive.

A human breast tumor cell line (BT-474) that supports mouse mammary tumor virus replication

SummaryA human breast tumor cell line BT-474 derived from an invasive ductal carcinoma was experimentally infected in vitro with a mouse mammary tumor virus from the RIII strain (RIII-MuMTV). The virus that replicated in the human cells was characterized as a mouse virus by immunofluorescence, electron microscopy and the presence of a specific RNA-directed DNA polymerase. The cells themselves were human as per the karyotype and isoenzyme migration patterns. It is concluded that human cells are susceptible to the mouse mammary tumor virus and can, eventually, support its replication.

Some aspects of the search for a human mammary tumor virus.

Some aspects of the search for a human breast cancer virus are discussed. Milk from 3 groups of women were studied: 1) Parsis India women 2) American women with a family history of breast cancer and 3) controls which were American woman with no history of breast cancer in their families. Viruslike (Type B) particles structurally similar to or identical with those responsible for transmitting mammary tumors in mice were found in 39% of 46 Parsis milks 31% of 101 milks of high-risk American women and 12% of 181 controls. However the incidence of breast cancer in the Parsis of Bombay was not much different from that in the U.S. (50-55/year/100000 population). This study was subject to error because screening for B particles by electron microscopy is extremely difficult and dependent on chance and the recognition of a B particle is not always absolute. It would seem that possibly inbreeding has resulted in an unusually high incidence of virus carriers but other factors have conveyed a high resistance to other cancers in Parsis. Studies on the effect of being breast-fed and the risk of developing breast cancer may be helpful in finding a prophylaxis for virus-caused breast cancer.

Possible role of genetic cell variants in the viral induction of mouse mammary tumors

SummaryOut of three attempts to induce neoplasia in normal C57B1 mammary epithelial cells with the mouse mammary tumor virus (MuMTV) only one presented signs of tumorigenicity. Immunofluorescence showed that virus synthesis took place in all three sublines but tumorigenicity as detected by cell aggregation viability (CAV) and transplantation into syngeneic mice failed to occur in two of them. By comparison, cells from a BALB/c spontaneous mammary tumor that do not express MuMTV were 100% tumorigenic, whereas cells from a BALB/cfC3H tumor with a 95% virus-producing cell population had a normal CAV and were tumorigenic only in 60% of the test animals. This lack of correlation suggested that many of the virus-producing cells were not neoplastic and that neoplasia might occur under virus stimulation only if a restricted population of genetic cell variants existed. Accelerated tissue culture passages of virus-free C57B1 and BALB/c normal mammary cells resulted in their spontaneous neoplasia at Passages 23 and 50 respectively; when duplicated cells cryopreserved in early passages were revived and cultivated in the same manner, neoplasia occurred at Passages 27 and 58. The similarity of the passage numbers appears to confirm the existence of genetic cell variants among the normal cell population.

Introduction of Madame Emilienne Wolff and Professor Etienne Wolff.

It is indeed a great pleasure and a privilege for me to welcome today Madame Emilienne Wolff and Monsieur le Professeur Etienne Wolff, who so kindly agreed to cross the Atlantic to join us in this symposium organized in their honor. As you all know, Madame and Monsieur Wolff have been nominated Honorary Members of our Association not only in recognition of their innumerable contributions to the field of tissue culture, but more particularly for their pioneering studies in cancer research and on the mechanisms of differentiation. Such a distinction could not be conferred to more deserving scientists. Both of them are universally known, and their work is very familiar to all members of the H. B. Fell Division. Madame Wolff has a Doctor of Sciences degree, is a laureate from the French National Academy of Sciences and a Director of the Centre National de la Recherche Scientifique. For many years she dedicated herself, side by side with her husband, to the study of avian and mammalian sexual differentiation. Professor Etienne Wolff occupies the Chair of Experimental Embryology at the Coll6ge de France, one of the most prestigious institutions of higher learning in Europe; he is a Director of the Centre National de la Recherche Scientifique, a member of the Academy of Sciences and of many other foreign academies. As a philosopher and a writer, his literary successes won him a seat in the famed Acad6mie Fran~aise. Little did I know when I first met him in 1949 that one day I would be assigned the pleasant task of introducing him on such a happy occasion. I was then a young research fellow at the Institute for Cancer Research in Philadelphia, and Dr. Wolff was already an internationally known figure in the field of teratology. At that time the distance between a newly appointed assistant and a faculty professor was forbidding, and only the