Alfred H. Handler

BIOLOGICAL STUDIES OF ACTINOMYCIN D

In the summer of 1954, after scientific discussions between Selman A. Waksman and Sidney Farber, a preparation of actinomycin D, made available through the kindness of S. Waksman,’ was subjected to preliminary trial in the Mouse Bioassay Unit of The Children’s Cancer Research Foundation. An evaluation of results soon indicated that this substance possessed activity of a high degree against many of the rodent tumors routinely utilized a t that time (TA-

Differentiation of normal and neoplastic cells maintained in tissue culture by implantation into normal hamsters.

Summary Quantitated inocula of 14 tissue culture cell lines which are remarkably similar in vitro were implanted into cheek pouches of unconditioned Syrian hamsters. All cell lines grew in the cheek pouch when 1 × 106 cells were implanted, but only those cell lines derived from neoplastic tissue produced tumors when inocula contained 1 × 104 cells. Other experiments indicated that this difference in the growth potential of cell lines deriving from neoplastic tissue also may be delineated in hamsters conditioned with cortisone acetate by implantation with 1 × 103 or fewer cells.

Chemotherapy studies on transplantable human and animal tumors in Syrian hamsters.

Experiments with human tumors grown in hamsters have been carried out in some detail in our laboratories in an attempt to formulate a methodology suitable for conducting chemotherapy studies. I t is hoped that the use of heterologously grown human tumors in animals will provide a screening method that may be a closer approximation of human neoplasia for screening purposes than is provided by the use of experimental animal tumors in a strictly homologous transplantation system. Although our present studies are based primarily on growth of human tumors in the hamster cheek pouch, they also incorporate homologously grown hamster tumors and heterologously grown animal tumors, in an effort to determine the influence of the host-transplant relationship on experimental chemotherapy. Eight years ago, in collaboration with Brenton R. Lutz and Donald I. Patt a t the Department of Biology, Boston University, Boston, Mass., I transplanted fragments of human tumor tissue to the cheek pouch of the Syrian hamster for the first time.lI Prior to this, Fulton et aL3 had used the hamster cheek pouch for microcirculatory studies. The cheek pouch was originally selected as a site for tumor transplantation because of its simple structure and the ease with which close observation and volumetric measurements of tumors implanted there can be made.4 Since that time we have repeatedly demonstrated the general excellence of these methods for the development of serially transplantable human tumors. Consequently, we now have a variety of tumors derived from children and adults5 in a state of readiness for experimental use. Although the cheek pouch of the hamster is highly suitable for the isolation and development of new tumors, its physical dimensions limit use of the preparation for the maintenance of large quantities of stock tumor. This problem has been met by transplanting cheek pouch tumors to intramuscular, intraperitoneal, and subcutaneous sites in the hamster. Intramuscular implants produce extraordinarily large tumors ideally suited for studies requiring tumor tissue in quantity (FIGURES 1 and 2), and they have the added advantage of re piring transplantation less frequentIy than do cheek pouch tumors. The present method of transplanting tissues to hamster cheek pouches is a modification of a technique described el~ewhere.~ Hamsters 5 to 8 weeks of age and of both sexes are used routinely for these studies. The hamster is anesthetized with Nembutalt administered intraperitoneally a t a dosage of 0.15 * The research for this paper was supported in part by Grant CY-3335 from the National Cancer Institute, Public Health Service, Bethesda, Md. t Veterinary Nembutal Sodium, 60 rng. per cc., was obtained from the Abbott Laboratories, North Chicago, 111.

Comparative effects of colchicine and vincaleukoblastine on bone marrow mitotic activity in Syrian hamster.

Summary The effect of Vincaleukoblastine and colchicine on mitotic activity of bone marrow cells was studied in the Syrian hamster. Vincaleukoblastine at a dosage of 1 mg/kg. administered intraperitoneally, caused metaphase arrest of all dividing cells. Colchicine, at a dosage of 1.2 mg/kg, which caused effective metaphase arrest of dividing cells in mice, rats, and other animals, did not demonstrate stathmokinetic effect in hamsters. A single injection of 2.4 mg/kg of colchicine caused partial metaphase arrest. There was no apparent increase in the stathmokinetic effect by increasing the dose of colchicine from 2.4 to 7.2 mg/kg. We are indebted to Miss A. Wagner for technical assistance, and to the Eli Lilly Co., Indianapolis, Ind., for a generous supply of Vincaleukoblastine.

Growth of Human Epidermoid Carcinomas (Strains KB and HeLa) in Hamsters from Tissue Culture Inocula.

Summary 1. The KB and HeLa strains of human epidermoid carcinoma have been established in the cheek pouches of golden hamsters by means of quantitated suspensions prepared from tissue cultures in a medium providing the specific amino acid and vitamin requirements of these cell lines. 2. Strain KB, isolated directly from a biopsy specimen in these media, has been grown in LAFi mice bearing homologous ACTH secreting pituitary tumors. This strain also has been established in the cheek pouch of non-conditioned hamsters but thus far has failed to grow in non-conditioned mice. 3. The use of quantitated tissue culture inocula for the production of tumors in the hamster cheek pouch for chemotherapeutic studies is suggested.

Tongue Lesions Specific for Diagnosis of Myopathy in Inbred Syrian Hamsters

Spontaneous muscular dystrophy in Syrian hamsters was first reported by Homburger et al. in 1962 (1) in one of their inbred strains. This dystrophy-like myopathic disease was found to be hereditary and transmitted by an autosomal recessive gene (designated cm, 1974) (2, 3). By selective breeding, it was possible to establish new dystrophic lines. These lines have been widely investigated, mainly because they present animal models in which to study the biochemistry and physiology of cardiomyopathy which might ultimately lead to clinical application (4-8). In the present investigation, experiments have been designed to study the physiology and immunology of fetal heart transplants in cheek pouches of hamsters of the myopathic strains. These studies will be reported elsewhere. In the course of observing the buccal tissue of the BIO® 14.6 myopathic strain, careful oral examination revealed small (1-2 mm), indurated, white lesions embedded in the undersurface of the tongue, slightly anterior to the frenulum linguae. Following the first observation, the oral cavities of other male and female hamsters of the stock BIO 14.6 strain were examined in age groups ranging from weanling to 6 mo. All of the observed hamsters of this strain showed tongue lesions beginning at 55 days. The lesions were not limited to the undersurface of the tongue, but were also apparent on both lateral surfaces and on the dorsum as well. The lesions were solitary or multiple and seemed to be confined to the anterior portion of the tongue. The findings of tongue lesions in the stock hamsters of BIO 14.6 strain confirmed the spontaneity of the lesions and indicated that their occurrence was in no way related to the transplantation experimentation.

EFFECT OF COLCHICINE ON HUMAN TUMOURS TRANSPLANTED IN CHEEK POUCH OF SYRIAN HAMSTER.

THE human tumour transplanted in the cheek pouch of the Syrian hamster has proved to be a useful tool for the examination of potential anti-tumour agents1,2. What appears to be an obvious advantage in using transplantable human tumours over transplantable animal tumours in chemotherapy investigations lies in the fact that a given compound can be assayed on cells of human origin growing in an in vivo system. However, at least two conditions would have to be fulfilled prior to making such a comparison: (1) transplanted human tumours should not undergo profound changes in their biological properties; (2) the host should not alter the effect of the tested agents on the human cells.

Homotransplantation of larynxes of cigarette smoke-exposed Syrian hamster.

In 20% of BIO inbred Syrian hamsters, carcinoma of the laryngeal respiratory epithelium developed after 70-100 wk of daily exposure to smoke generated from IRI Kentucky Reference cigarettes. Even larger numbers of smoke-exposed animals developed less severe epithelial changes in the area of the larynx bordering the vocal cords and including the ventricle of Morgagni (1). Under similar experimental conditions in smaller numbers of BIO 87.20 hamsters, laryngeal carcinoma occurred in 4 % of the animals, epithelial changes lesser than carcinoma in 13%, and metaplasia in 16%. Similar rates for laryngeal epithelial changes and carcinoma had previously been observed by German investigators using German Reference cigarettes and noninbred hamsters (2). The earliest malignant lesion induced by cigarette smoke in the hamster larynx was observed 73 wk after the start of inhalation, when the aged animal was close to death from degenerative disease attendant upon old age; therefore, little time remained for growth of the neoplastic lesion and metasta-tic spread in this animal (1). Actually, no metastases of laryngeal cancer were found in these experiments, although metastases of a smoke-induced nasopharyngeal sarcoma did occur. It was postulated that transplantation of a cigarette smoke-induced early laryngeal carcinoma might lead to further growth of the tumor in a new host. BIO 15.16 inbred hamsters, which had proved to be the most receptive hosts for homo- and isotransplantation (3), were chosen for the present study. Because of the microscopic nature of the induced laryngeal cancers, it was impossible to select by previous microscopic study the best possible lesions for transplantation; rather, the largest possible number of smoke-exposed larynxes was taken for transplantation into as many BIO 15.16 cheek pouches as possible. At the end of our smoke inhalation experiments, 15 larynxes of smoke-exposed BIO 15.16 animals and 34 larynxes of BIO 87.20 smoke-exposed animals were available as starting material.