Carcinogenesis and tumour development
Fig. 1: Multi-step concept of chemical carcinogenesis (from: Hengstler et al., Annu Rev Pharmacol Toxicol, 43, 485-520, 2003
Cell fate decisions: proliferation, apoptosis and senescence
In order to study the mechanisms responsible for cell fate decisions, cell and mouse systems are used where expression of oncogenes can be switched-on or -off by tetracycline-inducible systems.
Fig. 2: Induction of senescence by tetracycline-induced over expression of the oncogenic variant of the receptor tyrosine kinase erbB2 (NeuT) in MCF-7 breast cancer cells. An initially unexpected observation was that erbB2 did not induce the malignant properties of the cells but induced senescence which is characterised by cell cycle arrest, positive beta-glalactosidase staining and altered morphology with increased cell size and formation of granules. In contrast to apoptosis, senescent cells do not die but can be kept in culture for several months. A. Induction of NeuT expression by the TET-on system at various exposure periods with doxycycline. B. Native MCF-7 cells. C. Senescent MCF-7 cells after induced expression of NeuT. Induction of senescence is induced by a mechanism that involves P38 and P21. (Trost et al., 2005; Spangenberg et al., 2006). Oncogene-induced senescence can be interpreted as a fail-safe mechanism which protects cells from malignant transformation. Only when this fail-safe mechanism is bypassed cells can form tumors.
It is important to study whether mechanisms observed in cell culture are also relevant in vivo. This can be achieved in mouse systems or in human tumour tissue. Together with our cooperation partners Dr. Marcus Schmidt (Department of Gynaecology, University of Mainz) and Dr. Mathias Gehrmann (Siemens Medical Solutions, Köln), we have established a tumour bank including a set of Affymetrix gene expression data of 766 patients with node-negative breast cancer patients (Fig. 3).
Fig.
3: The B-cell metagene is associated with prognosis in node-negative breast
cancer patients. The aim of this study was to validate the hypothesis
that B-cell infiltration into breast cancer tissue antagonises formation of
metastasis. The applied clinical cohort contains a relatively high number of
patients (n=766) and consists of three subcohorts recruited from different hospitals
(Mainz, n=200; Rotterdam, n=286; Transbig, n=280). This gives us the opportunity
to study whether similar results can be obtained in three independent subcohorts.
In the case of the B-cell metagene, very similar results were obtained in all
three subcohorts (Schmidt et al., 2008; 2009).
Individual susceptibility to cancer /genome wide association studies
It is well known that genetic predisposition contributes to cancer risk. We have recruited blood samples from more than 1000 urinary bladder cancer cases and controls and have documented occupational exposure of these individuals to bladder carcinogens, particularly to aromatic amines and polycyclic aromatic hydrocarbons. Using SNP chips we have identified several SNPs and copy number variations that are associated with bladder cancer risk in a discovery cohort. Presently, these SNPs are validated in independent follow-up cohorts. We have contributed to a large genome wide association study with more than 4,000 urinary bladder cancer cases and 30,000 controls in which a sequence variant on 8q24 has been indentified that confers susceptibility to urinary bladder cancer (Kiemeney et al., 2009; Golka et al., 2009).
Selected publications
Schmidt M, Hengstler JG, von Törne C, Koelbl H, Gehrmann MC. Coordinates in the universe of node-negative breast cancer revisited. Cancer Res. 2009 Apr 1;69(7):2695-8.
Schmidt M, Böhm D, von Törne C, Steiner E, Puhl A, Pilch H, Lehr H-A, Hengstler JG, Kölbl H, Gehrmann M. The humoral immune system has a key prognostic impact in node-negative breast cancer. Cancer Res 2008;68:5405-13.
Tanner B, Hasenclever D, Stern K, Schormann W, Bezler M, Hermes M, Brulport M, Bauer A, Schiffer IB, Gebhard S, Schmidt M, Steiner E, Sehouli J, Edelmann J, Lauter J, Lessig R, Krishnamurthi K, Ullrich A, Hengstler JG. ErbB-3 predicts survival in ovarian cancer. J Clin Oncol. 2006 Sep 10;24(26):4317-23.
Spangenberg C, Lausch EU, Trost TM, Prawitt D, May A, Keppler R, Fees SA, Reutzel D, Bell C, Schmitt S, Schiffer IB, Weber A, Brenner W, Hermes M, Sahin U, Tureci O, Koelbl H, Hengstler JG, Zabel BU. ERBB2-mediated transcriptional up-regulation of the alpha5beta1 integrin fibronectin receptor promotes tumor cell survival under adverse conditions. Cancer Res. 2006;66(7):3715-25.
Trost TM, Lausch EU, Fees SA, Schmitt S, Enklaar T, Reutzel D, Brixel LR, Schmidtke P, Maringer M, Schiffer IB, Heimerdinger CK, Hengstler JG, Fritz G, Bockamp EO, Prawitt D, Zabel BU, Spangenberg C. Premature senescence is a primary fail-safe mechanism of ERBB2-driven tumorigenesis in breast carcinoma cells. Cancer Res. 65:840-9, 2005.
Hengstler JG, Bogdanffy MS, Bolt HM and Oesch F, Challenging Dogma: Thresholds for Genotoxic Carcinogens? The case of Vinyl Acetate, Annu Rev Pharmacol Toxicol, 43, 485-520, 2003.
Schiffer IB, Gebhard S, Heimerdinger CK, Heling A, Hast J, Wollscheid U, Seliger B, Tanner B, Gilbert S, Beckers T, Baasner S, Brenner W, Spangenberg C, Prawitt D, Trost T, Schreiber WG, Zabel B, Thelen M, Lehr HA, Oesch F, Hengstler JG. Switching off her-2/neu in a tetracycline-controlled mouse tumor model leads to apoptosis and tumor-size-dependent remission. Cancer Res. 63, 7221-31, 2003.
Schmidt M, Hasenclever D, Schaeffer M, Boehm D, Cotarelo C, Steiner E, Lebrecht A, Siggelkolw W, Weikel W, Schiffer-Petry I, Gebhard S, Pilch H, Gehrmann M, Lehr HA, Koelbl H, Hengstler JG, Schuler M. Prognostic effect of epithelial cell adhesion molecule overexpression in untreated node-negative breast cancer. Clin Cancer Res 2008;14:5849-55.
Golka K, Hermes M, Selinski S, Blaszkewicz M, Bolt HM, Roth G, Dietrich H, Prager HM, Ickstadt K, Hengstler JG. Susceptibility to urinary bladder cancer: relevance of rs9642880[T], GSTM1 0/0 and occupational exposure. Pharmacogenet Genomics. 2009 Oct 1. [Epub ahead of print]
Kiemeney LA,…, Golka K,…, Stefansson K. Sequence variant on 8q24 confers susceptibility to urinary bladder cancer. Nat Genet. 2008 Nov;40(11):1307-12.