Oncogene expression as detected by immunocytochemical staining in hormonally induced ovarian cell lines.

To understand the nature and extent of oncogene involvement in the development of neoplasia, an experimental model of goat ovarian granulosa cells stimulated by LH was chosen. In the course of these studies, several cell lines were developed which were essentially non-tumorigenic primary cell lines. One of them, however, was spontaneously transformed being immortalized and tumorigenic. These cell lines, transformed and non-transformed, should serve as contralateral cell lines to study differential oncogene expression in hormonally induced cell proliferation, and elucidate possible hormone-oncogene nexus which may be operative in the genesis of cancer. In the present report, we have studied expression of c-myc, c-ras, c-myb, c-fos and c-sis cellular oncogenes in the cell lines by immunocytochemistry using monoclonal antibodies. In the rest of our text we refer to these cellular oncogenes as oncogenes. The results reveal differential expression of the oncogenes. The striking difference between the non-transformed AIMS/GRXII cells and the transformed AIMS/GRXVIII cells was the absence of ras protein expression in the transformed AIMS/GRXVIII cells which intensely expressed the c-myc, c-myb, c-fos, and c-sis proteins. c-ras protein was expressed in the non-transformed AIMS/GRXVIII cell line and primary cultures. c-myc protein was expressed exclusively in the AIMS/GRXVIII transformed cells. The myc activity seen in the transformed cell line may be correlated to cell proliferation. These results show the variation of phenotype in cell lines derived from a single tissue source.

Morphological and functional characterization of a hormonally induced AIMS/GRXII cell line.

The AIMS/GRXII cell line is a product of the line of research our laboratory is pursuing to understand the response of target cells to sustained hormonal stimulation, a situation simulating the one that brings about in vivo tumorigenesis. The cell line was derived from goat ovarian granulosa cells subjected to luteinizing hormone stress (high doses repeated). It was found to be contact-inhibited, nontumorigenic and secreted progesterone. The majority of cells at any given passage showed hypodiploidy. The cell line required hormonal support till passage 8 after which it was hormone-independent. Thus, the system offers a phase-wise development of the cell line which might be useful in cancer research, particularly to understand the mechanisms of cell transformation at the cellular and molecular level and possible hormone (onco)gene nexus in cell proliferation.

The AIMS/GRXVIII cell line: 'spontaneous' transformation of hormonally induced primary cells derived from goat ovarian granulosa.

AIMS/GRXVIII is one of the cell lines developed in our laboratory from goat ovarian granulosa cells by luteinizing hormone (LH) stress. Unlike other cell lines in the AIMS/GR series which were contact-inhibited and non-tumorigenic, this one was 'spontaneously' transformed during passage 14 with a doubling time of 20 h. The morphology changed from a spindle shape to epithelial-like. Cultures lost contact inhibition and presented extensive mitotic and chromosomal abnormalities. The cultures secreted progesterone even without LH support after passage 8. The cells developed small tumours of luteal morphology in hamster cheek pouches, though they failed to form colonies in soft agar gel. This is a functional cell line and should be useful in understanding various processes in cell biology like function, signal transduction and mechanisms of cell transformation.

Alterations in lactate dehydrogenase isoenzymes and phosphofructokinase activity in the hormonally induced G-XII cell line.

G-XII cell line was earlier developed in our laboratory from the granulosa lutein cells of goat ovaries, subjected to sustained stimulation by ovine luteinizing hormone. It is a non-clonogenic and non-tumorigenic cell line which secretes progesterone. In the present paper, we report some biochemical findings on the cell line studied between passages 10 and 15. The cells exhibited a shift in the lactate dehydrogenase isoenzyme pattern from the heart form to muscle form and a 300% increase in the phosphofructokinase activity compared to fresh granulosa cells.

Use of in vitro method to predict response of human ovarian carcinoma cells to chemotherapeutic agents.

In vitro tissue culture and sensitivity tests were carried out on 16 cases of ovarian cancer to select the right anticancer drug(s) on an individual basis. The predictive accuracy of the in vitro drug sensitivity tests were 81.8%. The drug(s) suggested by in vitro tests did not reveal any correlation to the type of ovarian cancer. The drug sensitivity of cells from primary growth was different from that of secondary growth. The in vitro screening test also provided the choice of the next best drug(s), once the tumor had become resistant to a particular drug(s). Thus, the overall prognosis of patients at an advanced stage of malignancy could be improved with the help of in vitro predictive tests.

Effect of ovine luteinizing hormone and prolactin on progesterone secretion by goat granulose cells in culture.

Effects of LH and prolactin on cultures of granulosa cells from the goat were analysed in terms of the secretion of progesterone. The cultures were maintained for 120 h during which time they were treated at 24 and 72 h after explantation with LH and prolactin. Progesterone secreted in the culture medium was determined by radioimmunoassay. The secretion of progesterone by the cultures in response to LH and prolactin was significantly increased (P less than 0.01) compared with that by control cultures. The pattern of steroid secretion in the two cases (LH-treated and prolactin-treated cultures) was, however, different. The secretion dropped appreciably when the concentration of hormones was increased to 100 mu./ml.