Biomedical subjects

C C van Niekerk

Publications and source records attributed to C C van Niekerk.

15 recordsLinked to original sources

PubMed1999

Reduced expression of protein tyrosine phosphatase gamma in lung and ovarian tumors.

Based on LOH studies protein tyrosine phosphatasegamma (PTPgamma) has been suggested as a candidate tumor suppressor gene involved in the oncogenesis of lung and renal cancers. In order to assess the involvement of PTPgamma in tumor development we developed a PTPgamma-specific monoclonal antibody (gammaTL1) (IgM isotype) by immunization with a synthetic peptide of 15 amino acids corresponding to the amino acid sequence nos. 1423-1438 just outside the phosphatase domain-II. In line with the fact that the antibody was raised to an intracellular domain of the PTPgamma molecule the antibody labeled the cell membrane of fixed cells but did not stain the outside of the cell membrane in the immunofluorescence assay. The Mab gammaTL1 recognized a full-length baculovirus recombinant PTPgamma protein of 185 kDa, in addition to putative cleavage products of 120 kDa, 114/110 kDa and 80 kDa, on Western blots of lysates of PTPgamma-gene transfected Sf9 insect cells but not of tumor cell lysates. Based on immunoperoxidase and immunofluorescence assays on cryostat sections, however, PTPgamma was expressed in more than 90% of both normal, human tissue samples and in the (non-) tumor cells of carcinoma samples. However, PTPgamma was not found in 28% of the overall lung tumor samples, i.e. in 50% of the lung adenocarcinoma samples, while the expression was weak and heterogeneous in 71% of squamous lung cell carcinomas. PTPgamma was not suppressed in the normal cells between the lung carcinoma cells. The presence of PTPgamma, assayed by immunofluorescence in lung tumor cell lines (H69, H128, H82, C3) was confirmed by RT-PCR assay. Interestingly, the 90% expression score of PTPgamma protein in normal ovarian tissue samples was reduced dramatically to 44 and 38% in both the non-tumorous and tumorous cells, respectively, in ovarian tumor samples. PTPgamma was absent in the HT29 human colon carcinoma cell line both by immunofluorescence and RT-PCR assay. In summary, we have developed a PTPgamma-specific monoclonal antibody, that demonstrated that the expression of PTPgamma is severely reduced (>50%) in lung tumors and ovarian tumors.

Antibodies, Monoclonal↗

PubMed1997

Differentiation margins of ovarian tumor pathology: first incidences of epithelial ovarian tumors monitored by marker antibodies.

The first incidence of ovarian tumors in The Netherlands was analyzed during the PALGA data. The first incidences of benign epithelial ovarian tumors reach a plateau, at a level of 60 to 65 cases per 100,000 women beyond the age of 40 years. The borderline malignant epithelial ovarian tumors account for 10 per 100,000 women aged 30 to 85, while the ovarian carcinomas reach a plateau level of 25 to 35 per 100,000 women after the age of 50. Despite the long lag period (+/- 10 years) between benign and malignant ovarian tumors, the question of whether or not all epithelial ovarian cancers develop via an intermediate step of cystadenomas is still unanswered. Therefore, we examined whether the expression pattern of intermediate filaments and tumor antigens in normal, benign, and malignant ovarian tissues might contribute to this question. The following changes in expression pattern were observed: generally, all tumor cells retained the keratin profile of the corresponding original cell type. However, in a limited number of tumor samples ectopic keratin types, such as nos. 4, 10, 13, and 14, became expressed additionally. Most epithelial ovarian tumors and mesothelial cells coexpressed vimentin. The panepithelial marker BW495/36 clearly distinguished between negatively stained normal ovarian surface mesothelium and the positively stained (inclusion) cystic epithelium. TAG-72 as well as OV-632 marked a subsequent tumor stage by discriminating between negative serous adenomas and positive serious carcinomas. TAG-72, however, stained both mucinous adenomas and carcinomas. The ovarian tumor markers (OC125, OV-TL 33, OV-TL16, MOv18), all showed an increasing expression level in the sequence order from normal cells to benign and malignant ovarian tumors. Both our epidemiological and our immunohistochemical data have shown that in the Dutch population there is a lag period of at least 10 years between the plateau levels of benign and malignant ovarian tumors. The early transformation of mesothelial cells to benign and/or malignant tumors is clearly marked by a switch on of the BW495/36 marker. Although no general transformation or progression marker from adenomas to carcinomas emerged from this study, TAG-72 might be considered a (progression) marker between the subgroup of benign and malignant serous ovarian tumors.

Age Factors↗

PubMed1993

OV-TL 12/30 (keratin 7 antibody) is a marker of glandular differentiation in lung cancer.

The immunoreactivity of OV-TL 12/30, a monoclonal antibody to keratin 7 was investigated on paraffin-embedded human lung cancer tissues of 61 patients. A modified AEC-immunoperoxidase method with pepsin pre-digestion was used. In normal lung tissue keratin 7 was found in bronchial and bronchiolar epithelium, pneumocytes and compound glands. Squamous metaplasia of the bronchial tree was negative. All 24 squamous cell carcinomas were negative irrespective of grade of differentiation. All differentiation grades of 20 adenocarcinomas including bronchioalveolar carcinomas were positive. Since six large cell anaplastic carcinomas did not react with keratin 7 antibody these tumours are considered to be of squamous cell rather than adenocarcinomatous origin. Small cell anaplastic carcinomas were negative in 10 of 11 cases. Our study demonstrates that this keratin 7 antibody is useful in differentiating between squamous cell carcinoma and adenocarcinoma of the lung and it may be particularly useful in making the correct diagnosis in small lung biopsy specimens.

Antibodies, Monoclonal↗

PubMed1991

Immunohistochemical demonstration of keratin 7 in routinely fixed paraffin-embedded human tissues.

The immunoreactivity of OV-TL 12/30, a monoclonal anti-keratin 7 antibody (Mab), was investigated on frozen as well as paraffin-embedded human tissues. Its reactivity patterns were compared with another well-characterized monoclonal antibody to keratin 7 (RCK 105), and with broadly cross-reacting monoclonal (OV-TL 12/5) as well as polyclonal (pKer) keratin antisera. In frozen sections of normal and malignant human tissues both keratin 7 Mabs gave similar staining patterns. The immunoreactivity for OV-TL 12/30 and the polyclonal antibody (pKer) in tissue sections fixed in 4 per cent formalin or Bouin solution, was completely restored when pretreated with 0.1 per cent pronase, 0.1 per cent trypsin in phosphate-buffered saline (PBS) or with 0.5 per cent pepsin in 0.01 N HCl. Except for loss of immunoreactivity on human normal stomach surface epithelium and glandular mucous cells, Mab OV-TL 12/30 reacted strongly positive with essentially all those formalin- or Bouin-fixed paraffin-embedded tissues that had been shown to stain in non-fixed, frozen sections. In addition to the good correlation in human tissues, a complete correlation between the reactivity on frozen and paraffin-embedded human carcinomas (n = 86) was found as well. While both RCK 105 (anti-keratin 7) and OV-TL 12/5 (anti-keratin 5, 7, 14, 19) did not stain on paraffin-embedded sections, the polyclonal control antiserum (pKer) lost immunoreactivity in some cell types (e.g. mucous cells in compound glands, hepatocytes, pancreatic acinar cells, and proximal and distal convoluted tubules of the kidney). Our study shows that the keratin 7 Mab OV-TL 12/30 is an excellent marker for tumour histopathology since it is reactive in paraffin-embedded formalin-fixed human tissues.

Antibodies, Monoclonal↗

PubMed1991

Comparative immunohistochemical study of four monoclonal antibodies directed against ovarian carcinoma-associated antigens.

The monoclonal antibodies OC 125, OV-TL 3, MOv 18, and OV-TL 23, which are directed against distinct ovarian carcinoma-associated antigens, are assessed in the present study for their diagnostic value. The expression of the antigens defined by these was studied in serial sections from 80 ovarian carcinomas and 103 nonovarian carcinomas obtained from 183 patients, using the immunoperoxidase technique. Immunoelectron microscopy demonstrated that the antigens were all localized on the tumor cell membrane. OC 125, OV-TL 3, and MOv 18 reacted positively with approximately 90% of the ovarian carcinoma samples (n = 80), whereas OV-TL 23 stained 76% of these samples. OC 125, OV-TL 3, and MOv 18 were also reactive with a majority of carcinomas derived from the cervix, endometrium and fallopian tube, while OV-TL 23 reactivity was primarily restricted to ovarian carcinomas. OC 125 and OV-TL 3 reacted respectively with 11% and 14% of the nongynecologic carcinomas tested (n = 64). Positive cases included breast, colon, and lung carcinomas. The antibodies MOv 18 and OV-TL 23 were found less reactive with nongynecologic carcinomas.

Antibodies, Monoclonal↗

PubMed1991

Marker profile of different phases in the transition of normal human ovarian epithelium to ovarian carcinomas.

To investigate whether early changes in the transformation of normal ovarian epithelial cells into tumor cells can be detected with monoclonal antibodies, a comparative immunohistochemical study was performed on normal human ovarian mesothelial cells, cystomas, cystadenomas, ovarian carcinomas, as well as granulosa cell tumor. Using monoclonal antibodies against different keratin subtypes, it was shown that mesothelial cells, ovarian cysts, cystadenomas, and carcinomas all reacted positively with broad-spectrum anti-keratin monoclonal antibodies (MAbs), as well as with MAbs to keratins 7, 8, 18, and 19. Keratins 4 and 13 were not found in mesothelial cells, but positive groups of cells were identified in several cystomas, adenomas, and carcinomas. While mesothelial cells did not react with the pan-epithelial marker BW495/36, invaginating metaplastic mesothelial cells, inclusion cysts, cystomas, adenomas, and carcinomas showed an increasing reactivity with BW495/36, with an increasing degree of malignancy. The reactivity of MAbs against ovarian carcinoma-associated antigens (OV-TL 3, OC 125, MOv 18, and OV-TL 10) was limited to weak staining reaction in some mesothelial cells but were found to be positive on more than 50% of the ovarian cystadenomas and more than 90% of the ovarian carcinomas. Thecal and granulosa cells of primordial, primary, and secondary follicles all reacted positively with antibodies to the broad-spectrum keratins OV-TL 12/5 and RCK 102, and to keratins 8 and 18, but not with keratins 4, 7, 13, and 19. These keratins decreased or disappeared in granulosa cells of mature follicles (Graafian follicles), whereas granulosa cell tumors did not react with anti-keratin antibodies. The reactivity of BW 495/36 was negative or limited to traces in some granulosa cells. Ovarian carcinoma-associated antigens were not expressed in granulosa cells or granulosa cell tumors. The data indicate that mesothelial cells undergoing metaplastic changes finally resulting in ovarian cystadenomas (and carcinomas) initiate the synthesis of a 200-kd glycoprotein recognized by MAb (BW 495/36), the production of ovarian carcinoma associated antigens, in addition to focal production of keratin 4 and/or 13, as seen in several samples. The granulosa cell tumors decrease or switch off their keratin production and remain negative for the 200-kd glycoprotein and the ovarian carcinoma-associated antigens.

Adenoma↗

PubMed1989

Marker profile of mesothelial cells versus ovarian carcinoma cells.

We investigated the marker profile of human ascitic and cultured mesothelial cells, and compared it to that of ovarian carcinoma cells which are related in terms of their histogenesis, unrelated colon carcinomas being used as reference. Mesothelial and ovarian carcinoma cells could not be distinguished by (intermediate) filament typing, using monoclonal antibodies (MAbs) to keratins, vimentins and desmins. Colon carcinomas differed from mesothelial cells and ovarian carcinomas by the absence of keratin-7 filaments. The epithelial marker BW 495/36 was completely negative on mesothelial cells and positive on all ovarian and colon carcinoma cells. While CEA was found on about 85% of all colon carcinomas, CEA expression on mesothelial cells and ovarian carcinoma cells was below 20%. The ovarian carcinoma markers (OV-TL 3, OV-TL 10, OC 125, MOV 18) were strongly positive on ovarian carcinomas and negative on colon carcinomas (or limited to traces of immunofluorescence on some samples). Although the mesothelial cells showed weak or negative reactivity with these markers, OC 125 antigen was found by immunoelectron microscopy on the surface of cultured mesothelial cells, and was shed in the culture supernatant at concentrations of 50, 28, and 25 CA 125 U/ml/10(4) positive cells. This suggests that mesothelial cells may be responsible for the synthesis of CA 125 in ascitic fluid. The data indicate that ovarian carcinomas, mesothelial cells and colon carcinomas can be distinguished using a combination of anti-keratin antibodies with BW 495/36 and anti-ovarian carcinoma markers.

Antibodies, Monoclonal↗

PubMed1989

Changing tumour antigen expression in metastatic hepatocellular carcinoma cells of the guinea pig.

Hepatocellular carcinoma cells (Line-10), obtained from ascitic fluid after diethylnitrosamine treatment of Sewall Wright strain-2 guinea pigs, produce solid (primary) tumours, lymph-node and lung metastases and malignant ascites when reinjected into animals of the same strain. Monoclonal antibodies were raised against the tumour cells by immunizing BALB/c mice with viable ascitic hepatocellular Line-10 tumour cells. Three hybridomas producing anti-Line-10 monoclonal antibodies were selected for further studies (10TL1, 10TL40 and 10TL43) and compared with monoclonal antibodies against intermediate filament keratins. The anti-Line-10 monoclonal antibodies did not cross react with Line-1 hepatocellular carcinoma cells, nor with normal guinea pig hepatocytes. When ascitic Line-10 cells form high papillary projections on the peritoneal surface, they significantly reduced their antigen expression of 10TL40 and of 10TL43 defined antigens, while the expression of 10TL1 defined antigens remained unaltered. Invading Line-10 cells in the deep submesothelial stromal tissue, however, lost reactivity with MoAb 10TL43 but not with the MoAb's 10TL40 and 10TL1. The antigens on lung- and lymphnode metastases remained largely unaffected. The reactivity with MoAb's 10TL40 and with 10TL43 was also lost upon prolonged culturing of Line-10 cells. The reactivity of Line-10 and Line-1 cells with all monoclonal antibodies against keratin filaments remained unaltered. Line-1 cells could be distinguished from Line-10 cells by the absence of any reactivity with the MoAb's 10TL1, -40, -43, but also by the fact that 100% of the Line-1 cells were positive with antibodies against keratins 5/8, 18, and 7.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1988

Characterization of a human ovarian carcinoma cell line, OTN 14, derived from a mucinous cystadenocarcinoma.

A human ovarian carcinoma cell line, OTN 14, has been established from malignant ascitic fluid of a patient with a well-differentiated mucinous cystadenocarcinoma of the left ovary. The cell line has been maintained in vitro for 6 months through 23 passages, growing in monolayers as well as in 3-dimensional clusters, with a population doubling time of 28 1/2 hr. The number of chromosomes per cell varied from 67 to 88, with a modal number of 86. Two characteristic marker chromosomes were recognized, consisting of partially deleted chromosome I. With a DNA index of 1.934 the tumour cell line was near tetraploid. The epithelial character of the OTN 14 cells was confirmed by a positive immunofluorescence reaction with monoclonal antibodies (MAbs) against different keratins, and when (immuno)electron microscopy was used, keratin filaments and small junctional complexes were observed. Vimentin was also expressed in these cells, while desmin was not detected. Cultured tumour cells reacted (weakly) positive with MAb OV-TL 3 as a marker for ovarian carcinomas, while reactivity with the anti-ovarian carcinoma MAb OC 125 was limited to a few cells, not permitting the detection of shed CA 125 antigen in the culture supernatant. Cells stained heterogeneously positive for CEA marker BW 431/31, the presence of which was confirmed by detection of CEA shed into the culture medium. The cell line released estradiol at a concentration of 130,000 pmol/L in the culture medium, while no progesterone or dehydroepiandrosterone sulphate were found. Electron microscopical evidence for steroid production was suggested in some cells showing "dense-core" vesicles near the Golgi areas. The OTN 14 tumour cells formed poorly differentiated tumour nodules in nude mice, and metastatic cells were also found in blood capillaries. Cell types with mucinous as well as endocrine characteristics were found.

Animals↗

PubMed1986

Monoclonal antibody against human ovarian tumor-associated antigens.

Mouse monoclonal antibodies (OV-TL 3) were raised against human ovarian tumor-associated antigens for diagnostic purposes. A cloned hybridoma cell line was obtained by fusion of murine myeloma cells with spleen lymphocytes from BALB/c mice immunized with a tumor cell suspension prepared from an ovarian endometrioid carcinoma. The antibodies were initially screened for their ability to bind on frozen sections of human ovarian carcinoma tissue and a negative reaction on gastric carcinoma tissue by indirect immunofluorescence. The reactivity of the selected OV-TL 3 clone (IgG1 subclass) was studied on normal and neoplastic tissues as well as on a cell line derived from the original tumor cell suspension used for immunization. OV-TL 3 antibodies stained frozen sections of human ovarian carcinomas of the following histological types: serous, mucinous, endometrioid, and clear cell. No reaction was found with breast cancers or other nongynecological tumors. No differences in staining pattern were observed between primary and metastatic ovarian carcinomas. OV-TL 3 antibodies brightly stained ovarian carcinoma cell clusters in ascitic fluids and left unstained mesothelial cells and peripheral blood cells. The OV-TL 3-defined antigen also remained strongly expressed on a cell line derived from the endometrioid ovarian carcinoma originally used for generation of OV-TL 3 clone. Reactivity was weak and irregular in a few ovarian cysts, while traces of fluorescence were sometimes detected in epithelial cells lining the female genital tract. In only 3 specimens of 15 endometrium carcinomas was weak focal reactivity with OV-TL 3 antibodies observed. The results of the immunofluorescence study were confirmed by the more sensitive avidin-biotin method and by 125I-labeled OV-TL 3 antibodies. Thus OV-TL 3 recognizes a common antigen for most ovarian carcinomas and may be a useful tool for rapid diagnosis of ovarian carcinomas.

Animals↗

PubMed1980