Establishment and characterization of a human ovarian granulosa tumor cell line (HSOGT)

We successfully established a novel ovarian granulosa tumor cell line (HSOGT). The tumor tissue of the ovary was derived from a 25 year-old Japanese woman under her consent. The cell line was maintained for over 14 months, subcultured more than 73 times, and had a population doubling time of 18.9 hours. Phase contrast microscopy displayed a pavement-like arrangement without contact inhibition. The chromosome number showed a wide distribution of aneuploidy and the mode was 83; many marker chromosomes were observed. The HSOGT was also successfully xenotransplanted into nude mice. The cell line produced estradiol and has preserved some characters of granulosa cells with stable growth in vitro. We firmly believe that this cell line will be a most useful tool for endocrinological investigation of human granulosa cells.     

Application of laser scanning cytometry to the analysis of chromosomal aberrations induced by benzo[a]pyrene in CHO-WBLT cells

BACKGROUND: A recently developed laser scanning cytometry technique was applied to cytometric studies to detect rapidly stable chromosomal aberrations induced by a carcinogen in a Chinese hamster fibroblast cell line, CHO-WBLT. METHODS: Individual chromosomes were collected from metaphase cells by a syringe technique and spread on slides. The DNA content of each chromosome stained with propidium iodide was measured with a laser scanning cytometer (LSC). A characteristic DNA histogram, designated as the "laser scanning karyotype (LSK)," was obtained from about 20,000 chromosomes of CHO-WBLT cells. Each chromosome was confirmed morphologically under the microscope by using a "re-location" system built into the LSC. RESULTS: A total of 21 chromosomes, including marker chromosomes specific to the cell line, were assigned to 10 major peaks in the LSK, which was analogous to the karyotype demonstrated with the classical Q-banding technique. In contrast, clonal sublines isolated after exposure to the carcinogen benzo[a]pyrene showed LSKs different from those found in untreated control cells, and seven of 20 clones were found to be abnormal, with a small number of chromosomal translocations and/or deletions, which were confirmed by Q-banding. CONCLUSIONS: The laser scanning cytometry technique was employed to detect stable chromosomal aberrations in CHO-WBLT cells after treatment with benzo[a]pyrene. The results obtained with this technique were comparable to those obtained by Q-banding; therefore, this method may be useful for rapid primary screening to detect stable, abnormal karyotypes induced by environmental chemicals and/or radiation.     

One of the duplicated matrix metalloproteinase-9 genes is expressed in regressing tail during anuran metamorphosis

The drastic morphological changes of the tadpole are induced during the climax of anuran metamorphosis, when the concentration of endogenous thyroid hormone is maximal. The tadpole tail, which is twice as long as the body, shortens rapidly and disappears completely in several days. We isolated a cDNA clone, designated as Xl MMP-9TH, similar to the previously reported Xenopus laevis MMP-9 gene, and showed that their Xenopus tropicalis counterparts are located tandemly about 9 kb apart from each other in the genome. The Xenopus MMP-9TH gene was expressed in the regressing tail and gills and the remodeling intestine and central nervous system, and induced in thyroid hormone-treated tail-derived myoblastic cultured cells, while MMP-9 mRNA was detected in embryos. Three thyroid hormone response elements in the distal promoter and the first intron were involved in the upregulation of the Xl MMP-9TH gene by thyroid hormone in transient expression assays, and their relative positions are conserved between X. laevis and X. tropicalis promoters. These data strongly suggest that the MMP-9 gene was duplicated, and differentiated into two genes, one of which was specialized in a common ancestor of X. laevis and X. tropicalis to be expressed in degenerating and remodeling organs as a response to thyroid hormone during metamorphosis.     

Re-expression of estrogen receptor alpha using a tetracycline-regulated gene expression system induced estrogen-mediated growth inhibition of the MDA-MB-231 breast cancer cell line.

Estrogen receptor (ER)-negative breast carcinomas are often difficult to treat with antiestrogens. This work was performed to determine if the re-expression of the human ER alpha could restore the hormone response of these cells. We have transfected the human wild-type ER alpha to an ER-negative breast cancer cell line (MDA-MB-231) using a tetracycline-regulated gene expression system. We obtained a new cell line, MDA-A4-5/2. Cell count and flow cytometry "S" phase cell fraction showed that 17-beta-estradiol induced an inhibition on the proliferation of these cells; on the contrary, the antiestrogens ICI 182 780, and tamoxifen blocked this effect. Finally, we demonstrated an induction of the endogenous progesterone receptor gene when ER alpha was present. These results suggest that the re-expression of ER alpha in ER-negative breast cancer cells recreate, at least partially, a hormone-responsive phenotype and may be useful as a therapeutic approach to control this pathology.     

Molecular cloning of hepatic mRNAs in Rana catesbeiana responsive to thyroid hormone during induced and spontaneous metamorphosis

Amphibian metamorphosis affords a useful experimental system in which to study thyroid hormone regulation of gene expression during postembryonic vertebrate development. In order to isolate gene-specific cDNA probes which correspond to thyroid hormone-responsive mRNAs, we employed differential colony hybridization of a cDNA library constructed from poly(A)+ RNA of thyroxine-treated premetamorphic tadpole liver. From an initial screening of about 6000 transformants, 32 "potentially positive" colonies were obtained. The recombinant cDNA-plasmids from 13 of these colonies plus two "potentially negative" colonies were purified for further study. Southern blot analysis of the plasmid DNA was employed to determine whether different cDNAs encoded for the same mRNA. The effect of thyroid hormone on the relative levels of specific mRNA species was examined by Northern analysis of liver RNA from premetamorphic tadpoles, thyroxine-treated tadpoles, and adult bullfrogs. Three independent cDNA clones were obtained which encoded thyroid hormone-enhanced mRNAs. We also obtained two independent cDNA clones encoding thyroid hormone-inhibited mRNAs and three independent clones encoding thyroid hormone-unresponsive mRNAs. The levels of two thyroid hormone-enhanced mRNAs and one thyroid hormone-inhibited mRNA were essentially the same in the thyroid hormone-treated tadpole liver and adult liver, suggesting that thyroid hormone induces stable changes in liver gene expression during spontaneous metamorphosis. Using selected cDNAs, RNA dot blot analysis of liver mRNA from tadpoles at different stages of metamorphosis showed that the level of one thyroid hormone-enhanced mRNA increased during late prometamorphosis and metamorphic climax. Similarly, a mRNA which was strongly inhibited by thyroid hormone treatment was observed to decline during prometamorphosis and reach undetectable levels during metamorphic climax. One mRNA was detected which was reproducibly inhibited by thyroid hormone treatment but which remained essentially unchanged during spontaneous metamorphosis. These results provide the first direct evidence for the coordinate and selective pretranslational regulation by thyroid hormone of several liver genes during the developmental process of metamorphosis.     

Juvenile hormone and juvenile hormone mimics inhibit proliferation in a lepidopteran imaginal disc cell line

The action of juvenile hormone (JH) and JH mimics have been examined in vitro by utilizing the imaginal disc-derived cell line, IAL-PID2. We have discovered that the cell line was responsive to JH and a variety of JH mimics. The most consistent response obtained in our studies was inhibition of cell proliferation, in the absence of 20-hydroxyecdysone (20E), which characteristically reduces cell proliferation in its own right in this cell line. JH-I, JH-III, methoprene, fenoxycarb, and farnesol significantly inhibited cell proliferation after 3 days of exposure of the cells in vitro to each of the compounds. Linoleic acid controls had no effect on proliferation in the cultures. The cell proliferation assay demonstrates the JH responsiveness of this cell line, but the concentrations of JH required were high compared to the concentrations of 20E needed for inhibition of proliferation in these cells.     

Characterization of a human follicular thyroid carcinoma cell line (UCLA RO 82 W-1)

A thyroid tumor cell line has been established from the metastases of a follicular carcinoma in a female patient. Although the primary tumor released thyroglobulin (Tg) into the circulation (greater than 10,000 ng/ml), the uptake of I131 was less than 2%. After 37 replications the doubling time was 4 days and confluency was reached after 7 days from inoculation of 3 x 10(7) cells. This human thyroid tumor cell line has now been growing in culture for several years. An aneuploid chromosomal pattern was observed (62-82 chromosomes). A pair of X chromosomes was present but no Y chromosome was found which is compatible with the female origin of the cell line. EM studies revealed the presence of microvilli. Immunoperoxidase staining using specific anti-human Tg antisera indicated the presence of Tg within the cells. Nude mice developed solid-cystic tumors within 6 months after injection of the cells. The basal release of immunodetectable Tg, as measured in a perifusion system, increased in response to thyroid stimulating hormone (TSH) (P less than 0.025) or TSH combined with theophylline (P less than 0.001). Unusual isoenzyme patterns for galactose-1-phosphate-uridyltransferase (GALT) and phosphoglucomutase1 (PGM1) were detected in the tumor, compared with normal human fibroblasts and blood cells and isoenzyme patterns from the patient's lymphocytes. Because this malignant human thyroid follicular cell line has retained the ability to synthesize Tg it represents a valuable model for the study of human follicular carcinomas.     

Effects of simulated microgravity on thyroid carcinoma cells

We aimed to investigate whether simulated microgravity on thyroid carcinoma cells could help to perform in vitro cancer studies such as antitumor drug tests more reliable and to spare animal experiments. We cultured cancer cells at 0 g to enable formation of three-dimensional multicellular tumor spheroids (MCTS), which will resemble the originating tumors. Under microgravity human follicular cells (ML-1 cell line) keep floating with-out stirring so that initial cell-cell interactions required for spheroid formation will be induced by forces due to biochemical components actually expressed on surfaces of cells, whereas gravity related push- or shear events will not influence MCTS formation. Within 12 hours of clinorotation the monolayer turned spontaneously into MCTS with remarkable features: An increase of extracellular matrix proteins and TGF-beta 1. Thyroglobulin, ft3 and ft4 secretion were markedly reduced. These data are in agreement with the observation that astronauts show low thyroid hormone levels after spaceflight.     

Establishment of a Ph1 chromosome-positive cell line from chronic myelogenous leukemia in blast crisis

A new hematopoietic cell line, designated KCL-22, was established in vitro by cultivation of pleural effusion cells obtained from a woman with chronic myelogenous leukemia in blast crisis. KCL-22 grew in suspension culture with a doubling time of 24 h and consisted of immature undifferentiated cells which were positive for periodic acid-Schiff and acid phosphatase staining. Chromosome analysis of the KCL-22 line showed a female karyotype with double Ph1 chromosomes and additional chromosome abnormalities. Its representative karyotype was 52,XX, + 1p-,+6,+8,+8,+8, t(9q+;22q-), +22q-. This cell line possessed receptors for the Fc portion of IgG, but lacked lymphoid cell characteristics and the Epstein-Barr virus-associated nuclear antigen. These results indicate that the KCL-22 cells were derived from chronic myelogenous leukemia cells. This cell line should prove useful for research involving various aspects of chronic myelogenous leukemia.     

Effects of retinoic acid on estrogen- and thyroid hormone-induced growth in a newly established rat pituitary tumor cell line.

In order to elucidate the complex mechanism(s) of action of steroid hormones, thyroid hormone and retinoic acid in pituitary mammotrophs, a clonal cell line (G3) was isolated from the rat pituitary tumor MtT/F84. G3 cells were found to secrete prolactin constitutively and to contain receptors for estrogen, glucocorticoid, progesterone and thyroid hormone. Stimulation of G3 cells with thyroid hormone resulted in a modest but significant increase in estrogen and progesterone receptor levels, however, retinoic acid treatment had no effect. Simultaneous addition of thyroid hormone and estrogen showed an additive effect on progesterone receptor levels in G3 cells. Thyroid hormone as well as estrogen enhanced the growth of G3 cells. Interestingly, retinoic acid was also found to enhance their growth but its enhancement was less potent than thyroid hormone and estrogen. Low concentrations of estradiol and thyroid hormone showed additive effects, but G3 cells stimulated with high concentrations of thyroid hormone failed to elicit an additive effect with estrogen, suggesting the presence of a common pathway in the growth-stimulatory actions of these hormones. In addition, exposure of G3 cells to retinoic acid completely abolished the effects of estrogen or thyroid hormone in terms of cell growth. These results suggest that there are complex interactions in the signalling pathways for estrogen, thyroid hormone and retinoic acid action in G3 cells.     

Dexamethasone stimulates thyrotropin-releasing hormone production in a C cell line

The hypothalamic peptide hormone TRH is also found in other tissues, including the thyroid. While TRH may be regulated by T3 in the hypothalamus, other regulators of TRH have not been identified and the regulation of TRH in nonhypothalamic tissues is unknown. We recently demonstrated the biosynthesis of TRH in the CA77 neoplastic thyroidal C cell line. We studied the regulation of TRH by dexamethasone in this cell line because glucocorticoids have been postulated to inhibit TSH secretion by decreasing TRH in the hypothalamus. Furthermore, TRH in the thyroid inhibits thyroid hormone release. Thus by regulating thyroidal TRH, glucocorticoids could also directly affect thyroid hormone secretion. Treatment of CA77 cells for 4 days with dexamethasone produced dose-dependent increases in both TRH mRNA and cellular and secreted TRH. Increases in TRH mRNA and peptide levels could be seen with 10(-9) M dexamethasone. A 4.8-fold increase in TRH mRNA and a 4-fold increase in secreted peptide were seen with 10(-7) M dexamethasone. Dexamethasone treatment did not increase beta-actin mRNA levels or cell growth. These results suggest that glucocorticoids may be physiological regulators of TRH in normal C cells. In addition to their inhibitory effects on TSH, glucocorticoids may decrease thyroid hormone levels by increasing thyroidal TRH. Since the glucocorticoid effects on C cell TRH are the converse of what is expected for hypothalamic TRH, glucocorticoid effects in these two tissues may be mediated by different regulators.     

An alpha-subunit-secreting cell line derived from a mouse thyrotrope tumor.

The anterior pituitary contains multiple distinct endocrine cell types that secrete individual hormones. To derive a pure cell culture population in which to study the regulation of the alpha-subunit of TSH free of other hormones and cell types, we have developed a clonal continuous cell line from the transplantable thyrotrope tumor MGH101A. This cell line expresses alpha-subunit mRNA, secretes alpha-subunit protein, and has maintained a stable phenotype for over 3 yr in culture. However, as is the case for the transplantable tumor from which they are derived, these cells do not express the beta-subunit of TSH or respond to TRH or thyroid hormone. We have used this cell line to investigate regulation of the alpha-subunit mRNA by the second messengers, cAMP and phorbol esters, and by glucocorticoids. Phorbol esters increase alpha-subunit mRNA levels significantly (3.5-fold), as does cAMP (1.8-fold). In contrast, glucocorticoids decrease mRNA levels from cAMP-induced or basal levels (2-fold). These cells should prove valuable for study of alpha-subunit gene expression in an isolated renewable clonal cell culture system.     

HEC-1 cells

HEC-1 cell line was the first in vitro cell line of a human endometrial adenocarcinoma which enabled us to perform research work on the endometrium and endometrial carcinoma at a simplified cellular system, contributing cell and molecular biological studies on endometrial carcinoma. Once a cell line is established, it provides a stable experimental system that facilitates and progresses in the study of the tissues and/or neoplasias from which they are derived. In this article we report how HEC-1 cells have been established and cleared the proposed requirements to characterize the established cell line. Also to show the usefulness of the cell line for research work, once it was established, we illustrate these concepts by recalling results obtained with HEC-1 cells and reviewing the literature on what has been achieved by using these cells.     

Characteristics of cytotoxic thyroglobulin-specific T cell hybridomas

Clones of cytotoxic thyroid-specific T cell hybridomas were generated by fusion of thyroglobulin-primed, "in vitro"-boosted CBA lymph node cells with the AKR-derived lymphoma cell line BW 5147. One hundred and thirty one clones were obtained. Among them, 15 were able to induce the lysis of 51Cr-labeled syngeneic thyroid epithelial cells after 5 h of incubation at 37 degrees C. Two T cell clones, HTC1 and HTC2, were further studied. These clones, which exhibit cell surface characteristics of cytotoxic cells, were specific for only syngeneic thyroid cells (allogeneic thyroid cells or syngeneic epithelial cells were never lysed by these hybridomas). Moreover, by using Ag-pulsed syngeneic macrophages as targets, syngeneic cytotoxicity was shown to be specific for thyroglobulin and not for a nonrelated Ag. The lysis obtained with these autoreactive thyroid-specific T cell clones is restricted to class I major histocompatibility Ag. This property is assessed by both the blocking of syngeneic cytotoxicity toward thyroid epithelial cells or thyroglobulin-pulsed macrophages only by anti-class I mAb and by the detection of specific lysis of target cells exclusively when effector hybrid cells and target thyroid epithelial cells or thyroglobulin-pulsed macrophages shared at least class I major histocompatibility Ag.     

利用基因捕获技术建立稳定表达HBV的细胞模型

pGEM-HBV1.3质粒经HindIII限制性内切酶消化,将HBV1.3全长DNA切下,与同样经HindIII限制性内切酶降解过的PU21连接,得到PU21-HBV重组质粒。将该重组质粒采用电击转染方法导入HepG2细胞中,G418筛选阳性克隆并以X-gal染色,RT-PCR、Southern blot等方法验证HBV DNA的插入和表达。 PU21-HBV重组质粒经测序证明HBV1.3全长DNA正确与PU21载体连接,该重组质粒转染HepG2细胞后经G418筛选,得到一系列阳性克隆, Southern blot证实HepG2细胞基因组中含HBV DNA,RT-PCR结果表明HBV DNA在HepG2细胞中有功能基因的转录。HBV1.3已被整合在HepG2细胞染色体中并能稳定表达其RNA。稳定的HBV表达细胞模型构建成功。HBV表达细胞模型的建立,为进一步研究相关基因对HBV的转录、复制、转录后调节以及HBV各种蛋白的表达机理研究提供实验材料。     

Proliferation of bone marrow pro-B cells is dependent on stimulation by the pituitary/thyroid axis

The frequency and absolute number of pro-B, pre-B, and B cells in the bone marrow of the hypothyroid strain of mice are significantly reduced compared with those of their normal littermates. To investigate why this is the case, various B cell developmental processes were examined in the thyroid hormone-deficient mice. These studies revealed that the frequency of pro-B cells in the S-G2/M phase of the cell cycle was significantly reduced in hypothyroid mice. That thyroid hormone deficiency was responsible for this proliferation defect was established by demonstrating that treatment of hypothyroid mice with thyroxine resulted in a specific increase in the frequency and total number of cycling pro-B cells. The latter effect was paralleled by increases in the frequency and number of bone marrow B lineage cells. Additional in vitro experiments revealed that at least some thyroid hormone effects were directly mediated on the bone marrow. Taken together, these data demonstrate that thyroid hormones are required for normal B cell production in the bone marrow through regulation of pro-B cell proliferation and establish a role for the pituitary/thyroid axis in B cell development.