Jan Hein van Dierendonck

Bio: Jan Hein van Dierendonck is an academic researcher from Leiden University Medical Center. The author has contributed to research in topics: Programmed cell death & Apoptosis. The author has an hindex of 11, co-authored 11 publications receiving 554 citations. Previous affiliations of Jan Hein van Dierendonck include Leiden University.

Nuclear distribution of the Ki-67 antigen during the cell cycle: comparison with growth fraction in human breast cancer cells.

Abstract: It has been claimed that the commercially available Ki-67 monoclonal antibody recognizes a nuclear antigen which is solely expressed in cycling cells Therefore, at present, Ki-67 is increasingly used as a tool in evaluating growth fractions (GFs) of human tumors Here we describe specific patterns in the expression and topological distribution of this antigen during the cell cycle in MCF-7 human breast cancer cells Our results support earlier findings that the antigen belongs to a class of antigens associated with the structural organization of meta- and anaphase chromosomes, and proteins located near the cortical regions of prenucleolar bodies and nucleoli Using 5′-bromodeoxyuridine-labeling technology, we show that the expression may be undetectably low at the onset of DNA replication Comparison of Ki-67 fractions (KFs) and GFs as estimated from continuous 5′-bromodeoxyuridine-labeling curves revealed that KF was invariably higher than GF: in exponentially growing cov362c14 human ovary cancer cells, KF was only 35% higher than GF; in MCF-7 cells, 113 ± 46% In MCF-7 cultures either growing under suboptimal conditions or treated with 10-6m tamoxifen, the difference was more pronounced Furthermore, we evaluated the decrease of Ki-67-positive cells in nutritionally deprived and cell cycle-specific, drug-treated cultures Since the results indicate that nonproliferating cells may retain the antigen for a considerable period of time, KF may not always be a reliable indicator of GF

In situ detection of apoptosis during embryogenesis with annexin V: from whole mount to ultrastructure.

Abstract: Apoptosis is of paramount importance during embryonic development. This insight stems from early studies which correlated cell death to normal developmental processes and now has been confirmed by linking aberrant cell death patterns to aberrant development. Linking apoptosis to the phenotype of a developing organism requires spatial information on the localization of the dying cells, making in situ detection essential This prerequisite limits the tools available for such studies (1) to vital dyes, which can be detected at the whole mount level only; (2) to detection based upon apoptotic morphology by routine light microscopy and electron microscopy; and (3) to staining for apoptosis associated DNA fragmentation via, e.g., the TUNEL procedure, which marks cells in a relative late phase of apoptosis. New apoptosis markers need to be specific and should preferably detect cells early during this process. In the present study we show that the recently discovered in vitro marker of apoptosis, Annexin V meets these requirements for in vivo detection. Through intracardiac injections of biotin labeled Annexin V, a Ca2+ dependent phosphatidylserine binding protein, we were able to visualize apoptotic cells derived from each germ layer in the developing mouse embryo from the whole mount level up to the ultrastructural level. Double-labeling on paraffin sections for both this method and TUNEL revealed that cells become Annexin V-biotin labeled early during the process of apoptosis.

Bcl-2 and Bax proteins are present in interphase nuclei of mammalian cells.

Abstract: The Bcl-2 family of proteins comprises both cell death inhibiting and cell death promoting members, generally believed to be cytoplasmic and predominantly membrane-associated. Like Bcl-2, many Bcl-2-related proteins contain a C-terminal membrane insertion domain and much research is aimed at evaluating the functional role of their localization to the outer membranes of mitochondria, the endoplasmic reticulum, and perinuclear membranes. However, confocal fluorescence microscopy of human breast cancer cells and rat colon cancer cells immunostained with commercial antibodies raised against different epitopes of the anti-apoptotic Bcl-2 and the pro-apoptotic Bax protein revealed that these proteins are not only present in the cellular cytoplasm, but also within interphase nuclei. This was confirmed by Western blot analysis of isolated nuclei. In human cells, certain epitopes of Bcl-2, but not of Bax, were also found to be associated with mitotic chromatin. Anti-estrogen treatment of human breast cancer cells or transfection with antisense bcl-2 led to a reduction in both cytoplasmic and nuclear Bcl-2. Transfection of human bcl-2 and bax into rat cells resulted in cytoplasmic and nuclear Bcl-2 and Bax. This data seems in line with increasing evidence that the role of the Bcl-2 family of proteins should be extended to activities inside the nuclear compartment.

Mutations in exons 5-8 of the p53 gene, independent of their type and location, are associated with increased apoptosis and mitosis in invasive breast carcinoma

Abstract: In breast cancer, mutations located in the zinc-binding functional domains of the p53 gene have been reported to predict a worse prognosis and a worse response to treatment with doxorubicin, compared with mutations in other parts within exons 5–8 of the gene. Similarly, mutations in residues of p53 that directly contact DNA have been associated with a poor prognosis. To investigate whether these specific p53 mutations are associated with differences in the rate of apoptosis and/or mitosis, or expression of the anti-apoptotic Bcl-2 protein, these parameters were evaluated in 89 invasive breast cancers with a confirmed p53 mutation in exons 5–8 and in 99 tumours without a p53 mutation in exons 5–8. Neither mutations located in the zinc-binding functional domains nor mutations in residues that directly contact DNA were associated with alterations in mitotic or apoptotic activity. However, compared with the wild-type p53 tumours, both apoptotic and mitotic indices showed an approximately two-fold increase in the mutant p53 group ( p< 0·001). The presence of a p53 mutation was also associated with the presence of tumour necrosis ( p< 0·001), high tumour grade ( p< 0·001) and low expression of Bcl-2 ( p< 0·001). Our data support the concept that in invasive breast carcinoma, loss of p53 function is involved in enhanced proliferation rather than decreased apoptosis and that the resulting acceleration of cell turnover may enhance clonal evolution and tumour progression. Copyright © 1999 John Wiley & Sons, Ltd.

The Ki‐67 protein: From the known and the unknown

Abstract: The expression of the human Ki-67 protein is strictly associated with cell proliferation. During interphase, the antigen can be exclusively detected within the nucleus, whereas in mitosis most of the protein is relocated to the surface of the chromosomes. The fact that the Ki-67 protein is present during all active phases of the cell cycle (G(1), S, G(2), and mitosis), but is absent from resting cells (G(0)), makes it an excellent marker for determining the so-called growth fraction of a given cell population. In the first part of this study, the term proliferation marker is discussed and examples of the applications of anti-Ki-67 protein antibodies in diagnostics of human tumors are given. The fraction of Ki-67-positive tumor cells (the Ki-67 labeling index) is often correlated with the clinical course of the disease. The best-studied examples in this context are carcinomas of the prostate and the breast. For these types of tumors, the prognostic value for survival and tumor recurrence has repeatedly been proven in uni- and multivariate analysis. The preparation of new monoclonal antibodies that react with the Ki-67 equivalent protein from rodents now extends the use of the Ki-67 protein as a proliferation marker to laboratory animals that are routinely used in basic research. The second part of this review focuses on the biology of the Ki-67 protein. Our current knowledge of the Ki-67 gene and protein structure, mRNA splicing, expression, and cellular localization during the cell-division cycle is summarized and discussed. Although the Ki-67 protein is well characterized on the molecular level and extensively used as a proliferation marker, the functional significance still remains unclear. There are indications, however, that Ki-67 protein expression is an absolute requirement for progression through the cell-division cycle.

X-tile: a new bio-informatics tool for biomarker assessment and outcome-based cut-point optimization

Abstract: The ability to parse tumors into subsets based on biomarker expression has many clinical applications; however, there is no global way to visualize the best cut-points for creating such divisions. We have developed a graphical method, the X-tile plot that illustrates the presence of substantial tumor subpopulations and shows the robustness of the relationship between a biomarker and outcome by construction of a two dimensional projection of every possible subpopulation. We validate X-tile plots by examining the expression of several established prognostic markers (human epidermal growth factor receptor-2, estrogen receptor, p53 expression, patient age, tumor size, and node number) in cohorts of breast cancer patients and show how X-tile plots of each marker predict population subsets rooted in the known biology of their expression.

Glutathione in Cancer Biology and Therapy

Abstract: The glutathione (GSH) content of cancer cells is particularly relevant in regulating mutagenic mechanisms, DNA synthesis, growth, and multidrug and radiation resistance. In malignant tumors, as compared with normal tissues, that resistance associates in most cases with higher GSH levels within these cancer cells. Thus, approaches to cancer treatment based on modulation of GSH should control possible growth-associated changes in GSH content and synthesis in these cells. Despite the potential benefits for cancer therapy of a selective GSH-depleting strategy, such a methodology has remained elusive up to now.Metastatic spread, not primary tumor burden, is the leading cause of cancer death. For patient prognosis to improve, new systemic therapies capable of effectively inhibiting the outgrowth of seeded tumor cells are needed. Interaction of metastatic cells with the vascular endothelium activates local release of proinflammatory cytokines, which act as signals promoting cancer cell adhesion, extravasation, a...

Technical aspects of immunohistochemistry.

Abstract: Immunohistochemistry is an integral technique in many veterinary laboratories for diagnostic and research purposes. In the last decade, the ability to detect antigens (Ags) in tissue sections has improved dramatically, mainly by countering the deleterious effects of formaldehyde with antigen retrieval (AR) and increasing sensitivity of the detection systems. In this review, I address these topics and provide an overview of technical aspects of immunohistochemistry, including those related to antibodies (Abs) and Ags, fixation, AR, detection methods, background, and troubleshooting. Microarray technology and the use of rabbit monoclonal Abs in immunohistochemistry are also discussed.

Proliferation Marker Ki-67 in Early Breast Cancer

Abstract: Molecular markers have been extensively investigated with a view to providing early and accurate information on long-term outcome and prediction of response to treatment of early breast cancer Proliferation is a key feature of the progression of tumors and is now widely estimated by the immunohistochemical assessment of the nuclear antigen Ki-67 The expression of Ki-67 correlates with other measurements of proliferation, including S-phase and bromodeoxyuridine uptake High Ki-67 is a sign of poor prognosis associated with a good chance of clinical response to chemotherapy, but its independent significance is modest and does not merit measurements in most routine clinical scenarios However, its application as a pharmacodynamic intermediate marker of the effectiveness of medical therapy holds great promise for rapid evaluation of new drugs