cyclic-gmp and Uterine-Neoplasms

The serotonin transporter (SERT) is an oligomeric glycoprotein with two sialic acid residues on each of two complex oligosaccharide molecules. In this study, we investigated the contribution of N-glycosyl modification to the structure and function of SERT in two model systems: wild-type SERT expressed in sialic acid-defective Lec4 Chinese hamster ovary (CHO) cells and a mutant form (after site-directed mutagenesis of Asn-208 and Asn-217 to Gln) of SERT, QQ, expressed in parental CHO cells. In both systems, SERT monomers required modification with both complex oligosaccharide residues to associate with each other and to function in homo-oligomeric forms. However, defects in sialylated N-glycans did not alter surface expression of the SERT protein. Furthermore, in heterologous (CHO and Lec4 cells) and endogenous (placental choriocarcinoma JAR cells) expression systems, we tested whether glycosyl modification also manipulates the hetero-oligomeric interactions of SERT, specifically with myosin IIA. SERT is phosphorylated by cGMP-dependent protein kinase G through interactions with anchoring proteins, and myosin is a protein kinase G-anchoring protein. A physical interaction between myosin and SERT was apparent; however, defects in sialylated N-glycans impaired association of SERT with myosin as well as the stimulation of the serotonin uptake function in the cGMP-dependent pathway. We propose that sialylated N-glycans provide a favorable conformation to SERT that allows the transporter to function most efficiently via its protein-protein interactions.

Topics: Animals; Carrier Proteins; CHO Cells; Choriocarcinoma; Cricetinae; Cyclic GMP; Cyclic GMP-Dependent Protein Kinases; Female; Gene Expression; Glycosylation; Macromolecular Substances; Membrane Glycoproteins; Membrane Transport Proteins; Mutagenesis, Site-Directed; N-Acetylneuraminic Acid; Nerve Tissue Proteins; Nonmuscle Myosin Type IIA; Peptide-N4-(N-acetyl-beta-glucosaminyl) Asparagine Amidase; Phosphorylation; Pregnancy; Protein Conformation; Rats; Serotonin; Serotonin Plasma Membrane Transport Proteins; Structure-Activity Relationship; Transfection; Tumor Cells, Cultured; Uterine Neoplasms

Changes in urinary cyclic nucleotide levels have been reported in patients with various types of cancers. The present study was conducted to relate changes in urinary levels of cyclic guanosine monophosphate (cGMP) and cyclic adenosine monophosphate (cAMP) to the clinical outcome of 11 patients treated for cancer of the uterine cervix. Urine was sampled for 24 h before and 3 months after primary treatment. The levels of cGMP increased in all the patients (n = 5) who relapsed within the observation period of 39 months. 4 of these patients showed an increased cGMP/cAMP ratio. In the patients without relapse (n = 6), the cGMP levels decreased, whereas the cGMP/cAMP ratios were unchanged. No marked changes in the levels of cAMP were observed for either of the groups. The measurement of urinary cGMP levels seems to be a valuable tool in the follow-up of patients with cancer of the uterine cervix.

Topics: Adult; Aged; Biomarkers, Tumor; Cyclic AMP; Cyclic GMP; Female; Humans; Middle Aged; Prognosis; Uterine Neoplasms

The serotonin transporter expressed in brain, platelets, and placenta is a primary target for antidepressants, cocaine, and amphetamines. Here we report that interleukin-1 beta is a potent regulator of the expression of this transporter. The activity of the serotonin transporter in human JAR choriocarcinoma cells is stimulated by this cytokine and the stimulation is accompanied by an increase in the steady state levels of the transporter mRNAs and in the transporter density. The increase in mRNA levels is effectively blocked by actinomycin D. The stimulatory effect of interleukin-1 beta is not associated with any change in the cellular levels of cAMP, indicating involvement of a cAMP-independent pathway. Even though cholera toxin, which is known to increase cAMP levels, also upregulates the serotonin transporter in JAR cells, the effects of interleukin-1 beta and cholera toxin on the transporter activity are additive. This constitutes the first report on the identification of a physiologically occurring hormone/cytokine which upregulates the expression of the human serotonin transporter gene.

Topics: Biological Transport; Carrier Proteins; Cell Line; Cell Membrane; Choriocarcinoma; Cocaine; Cyclic AMP; Cyclic GMP; Cycloheximide; Dactinomycin; Dose-Response Relationship, Drug; Female; Gene Expression Regulation, Neoplastic; Humans; Imipramine; Interleukin-1; Iodine Radioisotopes; Kinetics; Membrane Glycoproteins; Membrane Transport Proteins; Nerve Tissue Proteins; Pregnancy; RNA, Messenger; Serotonin; Serotonin Plasma Membrane Transport Proteins; Time Factors; Tumor Cells, Cultured; Uterine Neoplasms

Topics: Adult; Carcinoembryonic Antigen; Cyclic AMP; Cyclic GMP; Female; Growth Hormone; Humans; Middle Aged; Thyroid Gland; Thyrotropin; Thyroxine; Triiodothyronine; Uterine Neoplasms

The addition of molybdate to intact or homogenized cells of the endometrial adenocarcinoma line HEC-1 during incubation with [3H]estradiol ([3H]E2) at 4 C causes substantial increases in cytoplasmic E2 binding levels. A similar effect can be observed in homogenates of normal human endometrium. These effects of molybdate appear to involve activation of E2-binding sites. Fractionation of the homogenates and recombination of different fractions revealed that activation of specific E2-binding sites by by MoO4= requires cytosolic factors as well as factors associated with the cell membrane. In homogenates of neoplastic cells (HEC-1) and normal endometrium, the addition of ATP, GTP, or cGMP was also found to increase E2 binding to levels as high as those obtained by the addition of MoO4=. In contrast, the addition of cAMP was found to lower specific E2 binding levels and to counteract the effects of MoO4=, ATP, GTP, and cGMP. Levels of intracellular cAMP and cGMP can change rapidly in cells in culture. Since cGMP causes E2 binding levels to increase while cAMP causes them to decrease, changes in the levels of these two cyclic nucleotides may explain the fluctuation in concentrations of specific estrogen binders that we have previously reported to occur in cultured endometrial cells.

Topics: Adenocarcinoma; Adenosine Triphosphate; Cell Line; Cell Membrane; Cyclic AMP; Cyclic GMP; Cytosol; Endometrium; Estradiol; Female; Guanosine Triphosphate; Humans; Molybdenum; Uterine Neoplasms

The ability to synthesize DNA and the cell cycle of normal trophoblastic cells and the trophoblastic cells of hydatidiform moles and invasive moles were studied by the autoradiographic technique. Compared with normal trophoblast, hydatidiform moles or invasive moles had a higher ability to synthesize DNA. cAMP tended to inhibit DNA synthesis in normal and molar tissue, whereas cGMP tended to promote it. The cell cycle time for each type of trophoblastic tissue was roughly 15 h; however, as compared to normal trophoblast, the hydatidiform or invasive moles had a longer S phase and a shorter G1 phase.

Topics: Autoradiography; Cell Cycle; Cell Division; Cyclic AMP; Cyclic GMP; Female; Humans; Hydatidiform Mole; Hydatidiform Mole, Invasive; Interphase; Nucleotides, Cyclic; Pregnancy; Trophoblasts; Uterine Neoplasms