Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P10415 (Bcl-2)
 33,771 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

During early pregnancy, the uterine endometrium responds to an implanting blastocyst with the extensive growth and differentiation of decidualization. This transformation of endometrial stromal cells begins in the antimesometrial side of the uterus to form a primary decidual zone, expands to form a secondary zone in the antimesometrium, and eventually transforms stromal cells in the mesometrial region. During pregnancy, both decidual zones regress by apoptosis, leaving decidual cells in the mesometrial region to form decidua basalis and the mature placenta. Molecular mechanisms controlling cell death during blastocyst implantation and decidualization are unknown. We examined the hypothesis that progesterone and estrogen control of endometrial differentiation and eventual apoptosis involves control of bcl-2 gene family expression. Ovariectomized rats were primed with estradiol and treated with progestin (medroxyprogesterone acetate, 3.5 mg) and estradiol (200 ng) before an intrauterine stimulus to initiate decidualization. Expression of the two bax messenger RNA transcripts, 1.0 and 1.5 kilobases, was examined by Northern blot analysis after hormone treatment and decidualization, and only the 1.0-kilobase transcript was induced. After the same treatments, the expression of bcl-2, a suppressor of apoptosis, decreased. In situ analysis revealed a cell type-specific increase in bax expression after the hormonal treatment and decidualization. This increase was first seen in luminal and glandular epithelial cells and then in the periluminal stroma 24 h after intrauterine stimulation, with eventual progressive expression throughout the stroma. Expression of bcl-2 decreased after hormone treatment and decidualization. Immunohistochemical studies of Bax showed that expression of Bax protein accompanied decidualization of the stroma. Bcl-2 protein was only seen in the luminal and glandular epithelia, and its level decreased as decidualization progressed. These data indicate that the balance between bax and bcl-2 expression is altered during stromal cell differentiation. Increased expression of bax precedes nucleosomal DNA fragmentation and eventual apoptosis, which plays a significant role in placental development.
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PMID:Effect of decidualization on the expression of bax and bcl-2 in the rat uterine endometrium. 877 Sep 38

Uterine leiomyoma is the most common benign smooth muscle cell tumor of the myometrium. Although Bcl-2 protein is known to be an apoptosis-inhibiting gene product and to prevent apoptotic cell death in a variety of cells, there are no published data regarding whether human leiomyomas express Bcl-2 protein. In the present study, we examined the expression of Bcl-2 protein in leiomyomas in comparison with that in the normal myometrium using an immunohistochemical method and immunoblot analysis with a monoclonal antibody to human Bcl-2 protein. Furthermore, we investigated whether sex steroid hormones could influence the levels of Bcl-2 protein expression in leiomyoma cells cultured in vitro under serum-free, phenol red-free conditions. Immunohistochemical staining for Bcl-2 protein was prominent in leiomyoma cells, but was scarcely present in normal myometrial smooth muscle cells. The expression of Bcl-2 protein in leiomyoma cells was most abundant in the secretory, progesterone-dominated, phase of the menstrual cycle, but was less abundant in the proliferative phase of the menstrual cycle. Western blot analyses of leiomyoma and myometrium tissue extracts revealed that Bcl-2 protein, with a molecular mass estimated at approximately 26 kDa, was abundantly present in leiomyoma tissue extracts, but was undetectable in normal myometrial tissue extracts. In monolayer cultures of uterine leiomyoma cells under a serum-free condition, the addition of progesterone (100 ng/mL) resulted in a striking increase in Bcl-2 protein expression in the cultured leiomyoma cells relative to that in control cultures, whereas the addition of 17 beta-estradiol (10 ng/mL) resulted in a reduction in Bcl-2 protein expression in the cells. The concentrations of sex steroids used were within the physiological tissue concentrations found in leiomyomas and myometrium. The present results suggest that the abundant expression of Bcl-2 protein may have a molecular basis characteristic of leiomyomas in the human uterus and that progesterone may play a vital role in the enhanced expression of Bcl-2 protein in human uterine leiomyoma cells.
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PMID:Increased expression of Bcl-2 protein in human uterine leiomyoma and its up-regulation by progesterone. 898 76

In the Syrian hamster, neonatal diethylstilbestrol (DES) treatment and then postpubertal estrogen stimulation induces hyperplasia plus apoptosis (preneoplastic responses) and ultimately neoplasia in the endometrial epithelial cell compartment. As part of a project to investigate the molecular and cellular mechanisms responsible for this phenomenon, expression of several proto-oncogenes (c-jun, c-fos, c-myc, bax, bcl-2 and bcl-x) was compared in estrogen-stimulated uteri from control versus neonatally DES-treated hamsters. According to Northern blot analysis of total uterine RNA, levels of the 3.2-kb c-jun and 2.4-kb c-myc transcripts were not altered by neonatal DES treatment. However, the 1.0 kb bax and 2.7 kb bcl-x transcript levels were significantly increased in the neonatally DES-exposed uteri. According to immunohistochemical analysis of paraformaldehyde-fixed and paraffin-embedded tissue sections, levels of c-Jun, c-Fos, c-Myc, Bax, and Bcl-x proteins were enhanced dramatically in both the luminal and glandular epithelial cells of neonatally DES-exposed uteri. In contrast, the immunostaining signal for Bcl-2 protein was decreased consistently in the epithelial cells of neonatally DES-exposed uteri. In conclusion, neonatal DES treatment induced persistent and epithelial cell-specific imbalances in the estrogen-regulated uterine expression of c-jun, c-fos, c-myc, bax, bcl-2, and bcl-x proto-oncogenes. These imbalances likely play a role in the molecular mechanism by which neonatal DES treatment induces altered estrogen responsiveness including hyperplasia, apoptosis, and ultimately neoplasia in the epithelial compartment of the hamster uterus.
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PMID:Neonatal diethylstilbestrol treatment alters the estrogen-regulated expression of both cell proliferation and apoptosis-related proto-oncogenes (c-jun, c-fos, c-myc, bax, bcl-2, and bcl-x) in the hamster uterus. 910 Oct 88

In the intracellular death program, hetero- and homodimerization of different anti- and pro-apoptotic Bcl-2-related proteins are critical in the determination of cell fate. From a rat ovarian fusion cDNA library, we isolated a new pro-apoptotic Bcl-2 gene, Bcl-2-related ovarian killer (Bok). Bok had conserved Bcl-2 homology (BH) domains 1, 2, and 3 and a C-terminal transmembrane region present in other Bcl-2 proteins, but lacked the BH4 domain found only in anti-apoptotic Bcl-2 proteins. In the yeast two-hybrid system, Bok interacted strongly with some (Mcl-1, BHRF1, and Bfl-1) but not other (Bcl-2, Bcl-xL, and Bcl-w) anti-apoptotic members. This finding is in direct contrast to the ability of other pro-apoptotic members (Bax, Bak, and Bik) to interact with all of the anti-apoptotic proteins. In addition, negligible interaction was found between Bok and different pro-apoptotic members. In mammalian cells, overexpression of Bok induced apoptosis that was blocked by the baculoviral-derived cysteine protease inhibitor P35. Cell killing induced by Bok was also suppressed following coexpression with Mcl-1 and BHRF1 but not with Bcl-2, further indicating that Bok heterodimerized only with selective anti-apoptotic Bcl-2 proteins. Northern blot analysis indicated that Bok was highly expressed in the ovary, testis and uterus. In situ hybridization analysis localized Bok mRNA in granulosa cells, the cell type that underwent apoptosis during follicle atresia. Identification of Bok as a new pro-apoptotic Bcl-2 protein with restricted tissue distribution and heterodimerization properties could facilitate elucidation of apoptosis mechanisms in reproductive tissues undergoing hormone-regulated cyclic cell turnover.
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PMID:Bok is a pro-apoptotic Bcl-2 protein with restricted expression in reproductive tissues and heterodimerizes with selective anti-apoptotic Bcl-2 family members. 935 61

Bcl-2-related anti- and proapoptotic proteins are important in the decision step of the intracellular death program upstream from the caspase proteases. Targeted overexpression of Bcl-2 in ovarian somatic cells of transgenic mice leads to decreased apoptosis of granulosa cells and is associated with higher ovulation rate, increased litter size, and ovarian teratoma formation. The ability of exogenous Bcl-2 proteins to promote follicle cell survival suggests that the transgene can bind to endogenous ovarian Bcl-2 family members and modulate the intracellular apoptosis process in favor of cell survival. We used the yeast two-hybrid system to search for ovarian Bcl-2 interacting proteins. The screening of an ovarian fusion complementary DNA library yielded several clones encoding for the death agonist Bcl-XL/Bcl-2-associated death promoter (BAD). Dimerization of Bcl-2-related proteins mediated by the consensus Bcl-2 homology (BH) domains is essential for their apoptosis-regulating function. Consistent with these observations, yeast two-hybrid assays indicated that the interaction of Bcl-2 with BAD is dependent on both BH4 and BH2 domains of Bcl-2. Northern blot analysis showed a wide distribution of BAD messenger RNA (mRNA) in diverse tissues with highest levels in the lung, ovary, uterus, and brain. In situ hybridization analysis indicated BAD mRNA expression in granulosa cells of different sizes of follicles and also in the theca and interstitial cells. BAD mRNA was expressed in the ovaries between postnatal 15-27 days and did not alter during the developmentally occurring apoptosis found about postnatal day 18 when the first group of early antral follicles were formed. Similarly, BAD mRNA levels did not change during follicle atresia induced by estrogen withdrawal in immature rats. To study the role of BAD in the ovary, BAD complementary DNA was transfected into primary cultures of granulosa cells and in a gonadal tumor cell line. Overexpression of BAD induced apoptosis in both cell types, and the effect of BAD was reversed by a membrane-permeable caspase inhibitor, indicating that BAD induces apoptosis via the activation of caspase cysteine proteases. In summary, the death agonist BAD was identified as a Bcl-2-interacting protein in the ovary, and BAD mRNA is constitutively expressed in granulosa cells, suggesting that BAD is an essential part of the ovarian cell death process. Because BAD overexpression in granulosa cells leads to apoptosis, future studies on ovarian BAD binding proteins and hormonal regulation of the interactions among different Bcl-2 family members could provide a better understanding of the cellular mechanism of ovarian follicle atresia.
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PMID:Expression and function of a proapoptotic Bcl-2 family member Bcl-XL/Bcl-2-associated death promoter (BAD) in rat ovary. 938 36

At the late secretory phase of the menstrual cycle and in early pregnancy, the uterine mucosa is infiltrated by large numbers of natural killer (NK) cells with a distinctive phenotype (CD56bright CD16- CD3-) and large granular lymphocyte (LGL) morphology. Circulating CD56bright NK cells generally proliferate in the presence of interleukin-2 (IL-2), but it is clear that cofactors besides IL-2 are required for optimal response. In the bone marrow, this co-stimulating signal is provided by stromal cells. In the present study we observe that uterine CD56+ cells from early pregnancy decidua similarly proliferate vigorously when cultured with decidual stromal cells and a suboptimal dose of IL-2. This response is dependent on cell-cell contact, as no proliferation of decidual NK cells was observed when they were separated from stromal cells by a permeable cyclopore membrane. In addition, we have studied the expression of Bcl-2 by decidual CD56+ cells. Our results show that the microenvironment of the uterus is likely to have a significant influence on the proliferation and survival of uterine CD56+ cells.
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PMID:Co-stimulation of human decidual natural killer cells by interleukin-2 and stromal cells. 1022 91

Preeclampsia is a serious pregnancy complication diagnosed by signs of widespread maternal endothelial dysfunction. In normal pregnancy, a subpopulation of placental cytotrophoblast stem cells executes an unusual differentiation program that leads to invasion of the uterus and its vasculature. This process attaches the conceptus to the uterine wall and starts the flow of maternal blood to the placenta. Preeclampsia is associated with abnormal cytotrophoblast differentiation, shallow invasion, and decreased blood flow to the placenta. To determine whether abnormal differentiation and/or hypoxia leads to cytotrophoblast apoptosis, we used the TUNEL (terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling) method to label DNA strand breaks in tissue sections of the placenta and the uterine wall to which it attaches. Control samples (n = 9) showed almost no apoptosis, but in samples from patients with preeclampsia, 15-50% of the cytotrophoblasts that invaded the uterine wall were labeled (8/9 samples). These same cells failed to stain for Bcl-2, a survival factor normally expressed by trophoblasts in both the placenta and the uterine wall. Our results show that preeclampsia is associated with widespread apoptosis of cytotrophoblasts that invade the uterus. The magnitude of programmed cell death in this population may account for the sudden onset of symptoms in some patients, as well as the associated coagulopathies.
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PMID:Preeclampsia is associated with widespread apoptosis of placental cytotrophoblasts within the uterine wall. 1039 61

Uterine leiomyomas appear during the reproductive years and regress after menopause, indicating the ovarian steroid-dependent growth potential. In order to characterize the molecular mechanism of sex steroidal regulation of leiomyoma growth, we examined whether sex steroids could influence the proliferation of leiomyoma cells. As epidermal growth factor (EGF) has been shown to mediate estrogen action and play a crucial role in regulating leiomyoma growth, we also investigated the effects of sex steroids on EGF and EGF receptor (EGF-R) expression in leiomyoma cells. In cultures of leiomyoma cells, the addition of either estradiol (E(2); 10 ng/ml) or progesterone (P(4); 100 ng/ml) resulted in an increase in proliferating cell nuclear antigen (PCNA) expression in the cells, whereas in cultures of normal myometrial cells, the addition of E(2) augmented PCNA expression in the cells, but P(4) did not. Immunoblot analysis revealed that leiomyoma cells contained immunoreactive EGF and that P(4) treatment resulted in an increase in EGF expression in the cells, whereas E(2) treatment resulted in a lower EGF expression in the cells. By contrast, E(2) treatment augmented EGF-R expression in cultured leiomyoma cells, but P(4) did not. These results indicate that P(4) upregulates the expression of PCNA and EGF in leiomyoma cells, whereas E(2) upregulates the expression of PCNA and EGF-R in those cells. It is, therefore, conceivable that P(4) and E(2) act in combination to stimulate the proliferative potential of leiomyoma cells through the induction of EGF and EGF-R expression. We also found that Bcl-2 protein, an apoptosis-inhibiting gene product, was abundantly expressed in leiomyoma relative to that in normal myometrium and that Bcl-2 protein expression in leiomyoma cells was upregulated by P(4), but downregulated by E(2). It seems, therefore, likely that P(4) may also participate in leiomyoma growth through the induction of Bcl-2 protein in leiomyoma cells. The abundant expression of Bcl-2 protein in leiomyoma cells may be one of the molecular bases for the enhanced growth of a leiomyoma relative to that of normal myometrium in the uterus.
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PMID:Molecular bases for the actions of ovarian sex steroids in the regulation of proliferation and apoptosis of human uterine leiomyoma. 1054 3

Histologic criteria defining malignancy in smooth muscle tumors are currently site specific. This study was undertaken to determine whether, in leiomyosarcomas (LMS) occurring in different anatomic locations, there were differences in patterns of expression of molecules that have been demonstrated to be associated with biologically aggressive behavior in malignant neoplasms, and also to determine their diagnostic utility. Formalin-fixed paraffin-embedded tissue blocks were selected from 16 extrauterine leiomyosarcomas (EULMS), 14 cases of uterine leiomyosarcomas (ULMS) and from five cases each of uterine and extrauterine leiomyomas (LM). Utilizing immunohistochemical (ABC) techniques with antigen retrieval, we assessed serial sections of each tumor for immunoreactivity with Glut1, CD44s, bcl2, cyclin D1, and estrogen receptor. Molecular genotyping for detecting k-ras-2 point mutation, p53 gene loss, and mdm2 gene amplification was performed on microdissected tumor samples from the same histologic sections. All of the uterine and extrauterine LM were diffusely positive for CD44s, bcl2, and cyclin D1, and uniformly negative for Glut1. In contrast, 50% of the ULMS and 25% of EULMS were Glutl positive. Moreover, Glut1 positivity closely correlated with aggressive biologic behavior reflected by distant metastatic spread. Eighty-percent of LM and 70% of the ULMS were estrogen receptor positive, whereas only one retroperitoneal tumor had focal weak positivity. Over 80% of the extrauterine and 50% of the uterine sarcomas showed absence of CD44s immunoreactivity. Percentage of cyclin D1 immunoreactivity was independent of tumor grade and inversely proportional to the percent of bcl2 positivity. An LMS of the male breast contained k-ras-2 exon 1 point mutation (codon 12 aspartate substitution of glycine). P53 allelic imbalance was present in 29% of ULMS and 57% EULMS. Mdm2 amplification was present in three of six EULMS but not in ULMS. In addition to clinical staging, Glut1 positivity together with patterns of immunoreactivity of CD44 and bcl2 may be helpful in identifying aggressive smooth muscle tumors of the uterus and some EULMS. The presence of estrogen receptor staining may be helpful in identifying uterine versus nonuterine LMS. Although sample numbers are too small for definite conclusions, this study suggests that there are differences in glucose transport, expression of adhesion molecules, and estrogen receptors in ULMS and EULMS, which in part may be due to the estrogen dependency of the ULMS. P53 mutations and mdm2 amplifications appear to be more frequent in EULMS.
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PMID:Comparative immunohistochemical and molecular analysis of uterine and extrauterine leiomyosarcomas. 1057 96

Pre-eclampsia is a serious pregnancy complication diagnosed by signs of widespread maternal endothelial dysfunction. In normal pregnancy, a subpopulation of placental cytotrophoblast stem cells executes a differentiation programme that leads to invasion of the uterus and its vasculature. This process attaches the conceptus to the uterine wall and starts the flow of maternal blood to the placenta. In pre-eclampsia, cytotrophoblasts fail to differentiate along the invasive pathway. The functional consequences of this abnormality negatively affect interstitial and endovascular invasion, thereby compromising blood flow to the maternal-fetal interface. To determine whether abnormal differentiation and/or hypoxia leads to apoptosis of invasive cytotrophoblasts, we used the TUNEL (terminal deoxynucleotidyl transferase-mediated dUTP nick end labelling) method to label DNA strand breaks in tissue sections of the placenta and the uterine wall to which it attaches. Control samples (n = 9) showed little or no apoptosis in any location, but in samples from patients with pre-eclampsia, 15-50% of the cytotrophoblast subpopulation that invaded the uterine wall was labelled (8/9 samples). These same cells failed to stain for Bcl-2, a survival factor normally expressed by trophoblasts in both the placenta and the uterine wall. Our results show that pre-eclampsia is associated with widespread apoptosis of cytotrophoblasts that invade the uterus. The magnitude of programmed cell death in this population may account for the sudden onset of symptoms in some patients, as well as the associated coagulopathies.
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PMID:Invasive cytotrophoblast apoptosis in pre-eclampsia. 1069 Aug 1


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