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Biomedical subjects

S Y Ying

Publications and source records attributed to S Y Ying.

At least 55 records · Page 3Linked to original sources
PubMed1998

Imbalanced expression of inhibin and activin subunits in primary epithelial ovarian cancer.

OBJECTIVES: Inhibins and activins are related gonadal peptides with opposing biologic actions on gonadotropin regulation, cell differentiation, and proliferation. The previous study of activin in ovarian cancer cell lines suggests that activin may promote growth of ovarian cancer. Elevated serum inhibin levels were also found in ovarian cancer patients; however, the source of elevated inhibin is unknown. This study is designed to examine the expression of inhibin and activin subunits as well as activin receptor in primary ovarian epithelial tumors to explore their role in the process of ovarian epithelial tumorigenesis. METHODS: The protein and mRNA expression of alpha and betaA subunits of inhibin/activin as well as of activin receptor mRNA were examined with immunohistochemistry (IHC) and reverse transcription-polymerase chain reaction (RT-PCR) in 112 ovarian carcinomas. Cases included 59 serous, 23 endometrioid, 16 mucinous, 9 clear cell, and 5 undifferentiated carcinomas. We also tested normal ovary and benign and borderline ovarian tumors for comparison. These included 17 ovarian surface epithelial samples, 6 serous and 5 mucinous cystadenomas, and 9 serous and 7 mucinous tumors of low malignant potential. A total of 139 ovarian tumors were analyzed by IHC and a total of 63 ovarian tumor samples were tested by RT-PCR. RESULTS: Inhibin alpha subunit expression was found in 47% of ovarian surface epithelia and focal alpha immunoreactivity was seen in tumor stroma, but was not found in the epithelial component of ovarian cystadenomas, tumors of low malignant potential (LMP), or carcinomas. Activin betaA subunit was expressed in 93% of surface epithelia, in the epithelial component of all cystadenomas, in 81% of LMP tumors, and in 72% of carcinomas, but not in tumor stroma. Activin expression did not correlate with histologic grades, tumor types, and surgical stages. Activin receptor type I and II mRNA-amplified products were found in virtually all the surface epithelial samples and ovarian tumors. CONCLUSIONS: The data suggest that imbalanced expression of inhibin and activin subunits in ovarian surface epithelium may represent an early event which leads to epithelial proliferation. Unopposed betaA and activin receptor expression in epithelial compartment of ovarian tumors suggest that activin may be available as autocrine and/or paracrine factors in ovarian epithelial tumors. But exact roles of inhibin and activin in ovarian epithelial tumors remain to be defined.

Activin Receptors↗
PubMed1997

Regulation of growth and prostatic marker expression by activin A in an androgen-sensitive prostate cancer cell line LNCAP.

Activin A, a homodimer of the betaA subunit of inhibin, is a member of the TGF-beta family. It is a multifunctional molecule regulating the growth, differentiation, and survival of a variety of cells. Treatment with activin A to an androgen-sensitive human prostatic cancer cell line LNCaP resulted in growth and morphological change and those were accompanied by up-regulation of prostatic differentiation markers prostate-specific antigen (PSA) and prostatic acid phosphatase (PAP). In addition, the expression of androgen receptor was also enhanced by activin treatment. These results suggest that activin has significant influence on LNCaP cells.

Acid Phosphatase↗
PubMed1997

Expression and localization of inhibin/activin subunits and activin receptors in the normal rat prostate.

Activin, a member of transforming growth factor beta (TGF beta), plays an important role during embryonic development, and defects of this growth factor results in degenerative disorders as demonstrated by gene knock out studies. TGF beta has been shown to have dual effects on the regulation of growth of prostate cancer cells. Recently, we have reported that activin was localized and messenger RNAs encoding activin and its receptors were expressed in human prostate cancer cells. To determine whether normal prostate cells produce inhibin and/or activin, immunohistochemistry was conducted on rat prostate glands using specific antibodies for inhibin and activin. The inhibin and activin were present in the cytoplasm and nuclei of epithelial cells whereas stromal cells were not stained. The expression of mRNA for the inhibin/activin subunits was determined using both in situ hybridization and the reverse transcription-polymerase chain reaction (RT-PCR) technique. In addition, the identity of the cDNA product of RT-PCR was verified with DNA sequencing. These findings suggest that inhibin is only produced and mRNA encoding the alpha-subunit for inhibin is only expressed in the normal rat prostate but activin and its receptors are produced and expressed in both normal rat prostate as well as human prostate cancer cells.

Activin Receptors↗
PubMed1997

Changes in the immunoreactivity for inhibin in mouse retina during development of photoreceptor cells.

Inhibin, a widely distributed, multifunctional member of the transforming growth factor beta superfamily, was originally isolated from ovarian follicular fluid. This molecule was recently localized in bovine and rat retina by immunohistochemistry and the mRNA encoding the alpha-subunit of inhibin was detected in the retina by in situ hybridization and the reverse transcription polymerase chain reaction. In this study we have examined, by immunohistochemical methods, the distribution pattern of inhibin in developing mouse eyes on days 10, 11, 14, 16, 18 of gestation (E0 = coitus) and postnatal days 0, 2, 4, 6, 8, 12, 16 and 18 of age (P0 = day of birth). Immunoreactivity for inhibin appeared on E10 (the earliest day of gestation examined) in the lens and in migrating large cells between the lens and the inner layer of the optic cup (future neurons of retina). On E16, cells located in the neuroblastic layer were stained. At birth (P0), the ganglion cells were heavily stained and some amacrine cells were weakly stained. By P4, the amacrine and bipolar cells were positively stained. The inner plexiform layer was heavily stained and the outer plexiform layer and horizontal cells were also apparent and stained. From P6 on, inhibin-immunoreactive staining was localized at the inner segment of the photoreceptor layer, and to ganglion cells in the inner nuclear layer (INL). By P12, ganglion cells, INL, and inner segments of the photoreceptor layer were heavily stained. The outer segments of the photoreceptor layer, presumably the interphotoreceptor matrix, were strongly stained with antibodies against the alpha-subunit, whereas the outer and inner plexiform layers were also moderately stained. The staining in the INL generally decreased with progressing age. We conclude that inhibin is expressed in the eye cup as early as day 10 of gestation, migrates toward the direction of pigmented epithelial layers and is concentrated in the interphotoreceptor matrix by P12, which showed a distribution pattern similar to that of the adult mouse. These findings suggest that inhibin may play a role in the development of the eye cup and the retina.

Animals↗
PubMed1997

Activins and activin receptors in cell growth.

Activin and inhibin, members of transforming growth factor-beta (TGFbeta) superfamily, have diverse and widespread effects within living organisms at many stages during growth and development. From the initial isolation of these growth factors based on their effects of FSH secretion, the study of these factors, as well as of the activin-binding protein follistatin, has progressed from the localization of the expression of the inhibin alpha subunit, activin betaA and betaB subunits, and activin receptors in the tissues of various organisms to the examination of activin and inhibin as autocrine and paracrine agents in cell proliferation and differentiation. The inhibitory effects on cell growth and differentiation that have been observed upon treatment of cells with activin suggest that further understanding of the bioactivity of this molecule and its characterization on a molecular level may aid in a more complete understanding of cell growth and differentiation. This minireview discusses the roles of activin, inhibin, and follistatin in the arenas of cell proliferation, differentiation, and embryogenesis, as well as the roles of these molecules in cancerous cells.

Activin Receptors↗
PubMed1996

Expression and localization of inhibin/activin subunits and activin receptors in MCF-7 cells, a human breast cancer cell line.

Inhibins and activins are members of the transforming growth factor-beta (TGF-beta) superfamily. Since TGF beta has been shown to be a potent proliferation-inhibiting agent for the breast cancer cell line MCF-7, we determined whether this cell line (a) transcribes messenger RNAs coding inhibin/activin alpha-, beta A-, and beta B-subunits and activin receptors, and (b) produces inhibin and/or activin proteins. Messenger RNAs for alpha- and beta-subunits of inhibin/activin and activin receptor II in MCF-7 cells were detected and localized using the reverse transcription-polymerase chain reaction (RT-PCR) analysis and in situ hybridization, respectively. The identity of the RT-PCR products was confirmed by DNA sequencing of PCR products. Immunocytochemically, inhibin and activin were localized in these cells. Our findings that messenger RNAs encoding inhibin alpha-subunit, inhibin/activin beta A-subunit, and activin receptor II were expressed, and inhibin/activin proteins were produced by MCF-7 cells, imply that these gonadal growth factors may have paracrine/autocrine functions in human breast cancer. Further, these observations suggest that these growth factors may be involved in regulating the growth and differentiation of human breast cancer cells.

Activin Receptors↗
PubMed1996

Expression and localization of inhibin/activin and activin receptors in GH3 cells, a rat pituitary adenocarcinoma cell line.

Inhibins and activins are members of the transforming growth factor beta (TGF beta) superfamily. Since TGF beta has been shown to be a potent proliferation-inhibiting agent for the pituitary adenocarcinoma cell line, GH3, we determined whether this cell line (a) transcribes mRNAs coding for inhibin/activin subunits (alpha and beta A) and activin receptors I, II, and IIB; and (b) produces inhibin and/or activin proteins. Messenger RNAs for the alpha- and beta A-subunits of inhibin and activin receptors I, II, and IIB in GH3 cells were detected and localized using the reverse transcription-polymerase chain reaction (RT-PCR) analysis and in situ hybridization, respectively. The identity of the RT-PCR products was confirmed by DNA sequencing of PCR products. Immunocytochemically, inhibin and activin were localized in these cells. Our findings indicate that messenger RNAs encoding inhibin alpha- and beta A-subunits and activin receptors I, II, and IIB were expressed, and inhibin/activin proteins were produced, by GH3 cells, imply that these gonadal growth factors may have paracrine/autocrine functions in rat pituitary adenocarcinoma. Further, these observation suggest that these growth factors may be involved in regulating the growth and differentiational of rat pituitary adenocarcinoma cells.

Activin Receptors↗
PubMed1996

Nasal foreign bodies in children.

This study investigates the pattern of pediatric nasal foreign body impaction and its management in a metropolitan area. Data was obtained from 147 children presenting to the Accident and Emergency Department over a 4-year period. The majority of foreign bodies were toys and household products. Complications which occurred, such as ingestion of the foreign body or epistaxis were usually related to attempts at removal. Fourteen cases of local complications resulted from button battery impaction. Most of these patients can successfully be managed without complication if correct procedures are adopted.

Child, Preschool↗
PubMed1995

Expression of activins and activin receptors in human retinoblastoma cell line Y-79.

Activin is a member of TGF beta family and is known to inhibit neuronal differentiation in certain tumor cell lines. In this study, the messenger RNA expression of activin subunits and activin receptors was characterized in retinoblastoma cell line Y-79 using the reverse transcription-polymerase chain reaction as well as in situ hybridization. The identity of the RT-PCR products was confirmed by DNA sequencing of PCR products. The activin protein production was determined by immunocytochemistry. We found that Y-79 cells transcribe mRNAs coding activin subunits and activin receptors and produce activin proteins. Our results imply that activin may have autocrine functions in these cells.

Activin Receptors↗
PubMed1995

Expression and localization of inhibin alpha-subunit in rat retinal photoreceptor cells.

To determine whether rat retinal photoreceptor cells produce inhibin, a molecule closely related to activin, a multifunctional growth factor in the transforming growth factor beta superfamily (TGF beta), we have conducted immunohistochemistry using specific antibodies for inhibin which were raised against a synthetic N-terminal fragment of the alpha-subunit of inhibin. The mature inhibin molecule was identified at both the inner and outer segments of photoreceptor cells. To determine if messenger RNA for the alpha-subunit of inhibin is expressed in the retinal cells, both in situ hybridization with a specific probe and the reverse transcription-polymerase chain reaction (RT-PCR) technique with primers specific for the alpha-subunit of inhibin were used. Messenger RNA expression of the alpha-subunit of inhibin was detected by RT-PCR and localized in the photoreceptor cells as determined by in situ hybridization. In addition, the identity of the cDNA product of RT-PCR was verified with Southern analysis and DNA sequencing. The localization of mature inhibin protein and its corresponding message to photoreceptor cells suggest that inhibin may have a paracrine function in the retina, perhaps in the photoreceptor cells themselves.

Animals↗
PubMed1995

Activin and activin receptors in the normal urinary bladder: immunohistochemistry, in situ hybridization, and RT-PCR.

To determine whether rat urinary bladder produces activin-A, a multifunctional growth factor in the transforming growth factor beta superfamily (TGF beta), we have conducted immunohistochemistry using specific antibodies for activin beta A-subunit which were raised against a synthetic cyclic fragment of the beta A-subunit of activin. The mature activin-A molecule was identified at transitional epithelial cells, smooth muscle, and endothelial cells. To determine if messenger RNAs for the beta A-subunits of activin-A and activin receptors are expressed in these cells, both in situ hybridization with specific probes and the reverse transcription-polymerase chain reaction (RT-PCR) technique with primers specific for the beta A-subunit of activin and activin receptors, respectively, were used. Messenger RNA expression of the beta A-subunit of activin-A and activin receptors were detected by RT-PCR and localized in the transitional epithelial, smooth muscle, and endothelial cells as determined by in situ hybridization. In addition, the identity of the cDNA product of RT-PCR was verified with DNA sequencing. The localization of mature activin-A protein and its corresponding message as well as that of activin receptors to urinary bladder cells suggest that activin-A may have an autocrine function in the urinary bladder, perhaps in the transitional epithelial, smooth muscle, and endothelial cells themselves.

Activin Receptors↗
PubMed1995

Expression and localization of activin beta A-subunit and activin receptors in TM3, a mouse Leydig cell line.

We have determined whether TM3 cells, a cell line derived from a murine Leydig cell tumor, (a) transcribe messenger RNAs encoding the beta A-subunits of inhibin/activin, and activin receptors I, II, and IIB, and (b) produce activin-A protein. Messenger RNAs for inhibin/activin beta A-subunits and activin receptors II, and IIB in TM3 cells were localized and expressed using in situ hybridization and the reverse transcription-polymerase chain reaction (RT-PCR) analysis, respectively. The identify of the RT-PCR products was confirmed by DNA sequencing of PCR products. Immunocytochemically, activin-A was localized in these cells. We observed that messenger RNAs encoding activin beta A-subunit as well as activin receptors II, and IIB were expressed and activin protein was produced by TM3 cells. These findings suggest that activin-A may have autocrine functions in TM3 cells and that activin-A may be involved in regulating the growth and differentiation of mouse Leydig cells.

Activin Receptors↗
PubMed1993

Activin enhances chondrogenesis of limb bud cells: stimulation of precartilaginous mesenchymal condensations and expression of NCAM.

The roles of activin action in chicken limb development were analyzed. Activin enhanced chondrogenesis up to five-fold in a concentration-dependent manner in limb bud micromass cultures, with a half-maximal dose around 30 ng/ml (1.25 nM). The response of limb bud cells (stage 22/23) to activin appeared higher within 24 hr after culture. Activin increased the size of precartilaginous condensations. No corresponding increase in cell number was observed with total DNA or [3H]thymidine incorporation. Activin treatment resulted in increased expression of NCAM in precartilaginous condensations and tenascin in cartilage nodules, suggesting that the mechanism of activin is mediated by increased cell adhesion and recruitment of mesenchymal cells into condensations. Our results demonstrate a novel function of activin and imply that activin, together with other TGF beta superfamily members, is involved in the induction of limb chondrogenesis.

Activins↗
PubMed1992

Inhibin production and secretion in human placental cells cultured in vitro.

In this study, human trophoblast cells were isolated from term placentas by trypsin-DNase digestion and Percoll gradient centrifugation. After the cells were cultured in vitro, bioactive inhibin and immunoreactive inhibin were measured in the culture medium and cellular lysate by an ovine pituitary cell culture system and an immunoenzymatic assay. The trophoblast cells were capable of producing inhibin, as indicated by the observation that enhancement of inhibin content and secretion was dependent upon the cell number and time in culture. High levels of inhibin were observed in the culture medium and the cellular lysate with cell numbers of over 1 x 10(6) cells/well, whereas the inhibin levels decreased until they were nearly undetectable when the cell number was less than 0.25 x 10(6) cells/well. In the culture medium, a sharp increase of inhibin levels was observed after 2 days of culture. Bio-inhibin and immuno-inhibin concentrations in the culture medium increased tenfold and fourfold, respectively, from day 2 to day 4. The peak level of bio-inhibin (3.5 U/mL) occurred on day 4 and that of immuno-inhibin (3.55 U/mL) on day 6. In contrast, the maximal level of bio-inhibin (4.45 U/mL) and immuno-inhibin (4.25 U/mL) in the cellular lysate was observed on day 2.(ABSTRACT TRUNCATED AT 250 WORDS)

Cell Separation↗
PubMed1991

Effects of interleukin-1 beta on secretion of follicle-stimulating hormone (FSH) and luteinizing hormone (LH) by cultured rat anterior pituitary cells.

Interleukin-1 beta (IL-1 beta) at doses of 0.15 and 1.5 nM significantly inhibited FSH secretion and stimulated LH secretion by cultured rat pituitary cells after 24-72 hr incubation whereas 15 pM of IL-1 beta was not effective. Treatment with IL-1 beta for 12-48 hr did not affect intracellular content of FSH. However, treatment with 0.15 and 1.5 nM of IL-1 beta for 72 hr significantly suppressed intracellular content of FSH whereas various doses of IL-1 beta incubated with the cells for 12-72 hr showed no effect on the intracellular content of LH. Pretreatment with IL-1 beta for 48 hr inhibited both GnRH-mediated LH and FSH secretions by the pituitary. The secretion of FSH and LH mediated by an activator of protein kinase C, phorbol 12-myristate 13-acetate, was also significantly suppressed by pretreatment with IL-1 beta for 48 hr. These results suggest that (a) IL-1 beta has opposite effects on the secretion of LH and FSH and (b) pretreatment with IL-1 beta suppresses GnRH-mediated stimulation of LH and FSH by the pituitary and this suppressive effect of IL-1 beta may involve the suppression of a protein kinase C-dependent mechanism.

Animals↗
PubMed1991

Transforming growth factor-beta and activin inhibit basal secretion of prolactin in a pituitary monolayer culture system.

Incubations of rat anterior pituitary cells with transforming growth factor (TGF)-beta 1 for 48 hr suppressed the secretion of basal prolactin (PRL) in a dose-dependent manner (ED50, 100 pg/ml). Activin, a gonadal hormone processing cysteine distribution similar to TGF beta, also suppressed basal PRL secretion, but it was less effective (ED50, 4 mg/ml). Treatment with TGF beta 1 significantly suppressed basal PRL secretion from the pituitary after 24 hr and up to 72 hr of incubation. TGF beta 1 also inhibited thyrotropin-releasing hormone-mediated PRL secretion and activin inhibited thyrotropin-releasing hormone-mediated PRL secretion slightly, but significantly. In addition, we also measured the secretion of growth hormone by cultured pituitary cells treated with TGF beta 1 or activin for 24 to 72 hr. TGF beta 1 and activin showed an opposite effect on growth hormone secretion; TGF beta stimulated and activin inhibited basal secretion of growth hormone. These results suggest that TGF beta 1 is a potent inhibitor of basal secretion of PRL by the pituitary, and both TGF beta 1 and activin play a multifunctional role in basal secretion of pituitary hormones.

Activins↗
PubMed1990

Isolation and characterization of human thyrotropin-releasing hormone (TRH) from an endocrine pancreatic tumor.

An extract of a pancreatic carcinoid tumor obtained at autopsy from a patient who had suffered from Cushing's syndrome was found to have the ability to release thyrotropin (but not any other pituitary hormones) from cultured rat anterior pituitary cells, and to bind to a specific thyrotropin-releasing hormone (TRH) antiserum. The tumor contained 2.2 and 3.9 nmol/g of TRH bio- and immunoreactivity, respectively. The active material was purified and its amino acid composition and chromatographic properties were found to be identical with those of synthetic ovine/porcine TRH. This represents the first isolation of human TRH and the first established case of a 'TRHoma', a TRH-producing tumor.

Adult↗