alpha-chymotrypsin and Uterine-Neoplasms

Human chorionic gonadotropin (hCG) contains five acidic N-linked sugar chains, which are derived from three neutral oligosaccharides by sialylation. Each of the two subunits (hCGalpha and hCGbeta) of hCG contain two glycosylated Asn residues. Glycopeptides, each containing a single glycosylated Asn, were obtained by digestion of hCGalpha with trypsin, and of hCGbeta with chymotrypsin and lysyl endopeptidase. Comparative study of the sugar chains of the four glycopeptides revealed the occurrence of site-directed glycosylation. Studies of the sugar chains of hCGs, purified from urine of patients with various trophoblastic diseases, revealed that choriocarcinoma hCGs contain sialylated or non-sialylated forms of eight neutral oligosaccharides. In contrast, hCGs from invasive mole patients contain sialyl derivatives of five neutral oligosaccharides. The structural characteristics of the five neutral oligosaccharides, detected in choriocarcinoma hCGs but not in normal placental hCGs, indicate that N-acetylglucosaminyltransferase IV (GnT-IV) is abnormally expressed in the malignant cells. This supposition was confirmed by molecular biological study of GnT-IV in placenta and choriocarcinoma cell lines. The appearance of tumor-specific sugar chains in hCG has been used to develop a diagnostic method of searching for malignant trophoblastic diseases. In addition, a summary of the current knowledge concerning the functional role of N-linked sugar chains in the expression of the hormonal activity of hCG has been presented.

Topics: Animals; Binding Sites; Carbohydrate Metabolism; Carbohydrate Sequence; Carbohydrates; Choriocarcinoma; Chorionic Gonadotropin; Chymotrypsin; Female; Glycopeptides; Glycosylation; Humans; Molecular Sequence Data; N-Acetylglucosaminyltransferases; Oligosaccharides; Pregnancy; Serine Endopeptidases; Trophoblastic Neoplasms; Trypsin; Tumor Cells, Cultured; Uterine Neoplasms

The pregnancy and tumor marker human chorionic gonadotropin (hCG) belongs to the family of the glycoprotein hormones. Information on epitope forming sequences of hCG and its subunits hCG alpha and hcg beta has significant impact on the examination of intra- and extracellular metabolism and the standardization of diagnostic assay systems. Variants of hCG appear in biological fluids with variable modifications on different parts of the molecule. These changes may influence the binding patterns of monoclonal antibodies (MCA), thereby causing erroneous results in hCG immunoassays. The aim of the present work was to investigate the influence of peptide bond cleavages and the loss of certain segments of the molecule, which were induced by proteases on the expression of the seven hCG alpha-(alpha 1-alpha 7), nine hCG beta- (beta 1-beta 9) and four hCG beta-core-fragment-epitopes (beta 10-beta 13), previously identified by us [1-10]. To this end, we digested hCG alpha and hCG beta with chymotrypsin. Hormone fragments were separated by high performance liquid chromatography (HPLC) and subsequently immunochemically examined by direct binding radioimmunoassay (DB-RIA), competitive RIA and immunoenzymometric assays (IEMA). Fractions containing hCG-like immunoreactivity were sequenced by Edman and carboxypeptidase-Y degradation. It appeared that: (I) Amino acids (AA) alpha 41-47 and the peptide bonds between AA alpha 40/41, alpha 47/48 and alpha 29/30 do not influence the expression of the 7 alpha-epitopes, (II) The absence of the hCG beta N-terminus plays a crucial role for the formation of epitopes beta 10 and beta 13. (III) Neither the presence nor the absence of the C-terminal peptide of hCG beta (hCG beta CTP, AA beta 114-145) has any importance for the expression of epitopes beta 1-beta 7 and beta 10-beta 13 (IV).(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Biomarkers, Tumor; Choriocarcinoma; Chorionic Gonadotropin; Chymotrypsin; Female; Humans; Infant, Newborn; Male; Peptide Fragments; Pregnancy; Pregnancy Tests, Immunologic; Structure-Activity Relationship; Testicular Neoplasms; Uterine Neoplasms

Fourteen cases of mixed müllerian tumour (MMT) of the endometrium, six stromal sarcomas, five uterine leiomyosarcomas, and five leiomyomas were examined, using an immunoperoxidase technique, for the presence of alpha-1-antitrypsin (A1AT), alpha-1-antichymotrypsin (A1ACT), actin, and myosin. In addition, six cases of endometrial adenocarcinoma were examined for the presence of A1AT and A1ACT. Eleven MMT were positive for A1AT and 13 for A1ACT. All stromal sarcomas, four adenocarcinomas, four leiomyomas, and three leiomyosarcomas were positive for both. All leiomyomas and leiomyosarcomas were positive for myosin as were seven. MMT and three stromal sarcomas. Four leiomyomas, four leiomyosarcomas, six MMT, and three stromal sarcomas were positive for actin. These findings are related to those in the normal uterus and their practical and theoretical significance discussed.

Topics: Actins; Adenocarcinoma; alpha 1-Antichymotrypsin; alpha 1-Antitrypsin; Chymotrypsin; Endometriosis; Female; Histocytochemistry; Humans; Leiomyoma; Leiomyosarcoma; Myosins; Sarcoma; Uterine Neoplasms

The immunologic reactivity of glycoprotein antigens extractable from individual, histologically different ovarian and uterine cancers was studied taking into account their relationship with carcinoembryonic antigen (CEA), nonspecific cross-reacting antigen (NCA), alpha-feto-protein (AFP), and alpha-1-antichymotrypsin. All studies were performed using specific immune sera against perchloric acid (PCA) extracts of ovarian mucinous cystadenocarcinoma (anti-PCA-CaOm) and cervical squamous cell carcinoma (anti-PCA-CaCx), and antisera against the reference antigens mentioned above. A considerable antigenic heterogeneity and the existence of several immunologically related antigenic systems were found: 1) CEA-like antigens; 2) NCA-type antigens; 3) an antigen different from CEA and NCA present in ovarian mucinous adenocarcinomas and often cross-reacting, but not identical with respective antigens of uterine body and cervical carcinomas; 4) an antigen reacting with anti-alpha-1-anti-chymotrypsin serum; and 5) an antigen reacting with anti-AFP serum.

Topics: Adenocarcinoma; alpha 1-Antichymotrypsin; alpha-Fetoproteins; Antigens, Neoplasm; Carcinoembryonic Antigen; Carcinoma, Squamous Cell; Cell Adhesion Molecules; Chymotrypsin; Cross Reactions; Cystadenocarcinoma; Female; Genital Neoplasms, Female; Glycoproteins; Humans; Immune Sera; Immunologic Techniques; Ovarian Neoplasms; Tissue Extracts; Uterine Cervical Neoplasms; Uterine Neoplasms