Analytical Cellular Pathology - Volume 32, issue 4

Authors: van Houdt, Winan J. | de Bruijn, Menno T. | Emmink, Benjamin L. | Raats, Danielle | Hoogwater, Frederik J.H. | Rinkes, Inne H.M. Borel | Kranenburg, Onno

Article Type: Research Article

Abstract: Background: Colon carcinomas frequently contain activating mutations in the K-ras proto-oncogene. K-ras itself is a poor drug target and drug development efforts have mostly focused on components of the classical Ras-activated MEK/ERK pathway. Here we have studied whether endogenous oncogenic K-ras affects the dependency of colorectal tumor cells on MEK/ERK signaling. Methods: K-ras mutant colorectal tumor cell lines C26, HCT116 and L169 were used. K-ras or components of the MEK/ERK and p38 pathway were suppressed by RNA interference (RNAi). MEK was inhibited by U0126. p38 was inhibited by SB203850. Results: MEK inhibition, or suppression of MEK1/2 or ERK1/2 …by RNA interference, reduced the proliferation rate of all colorectal cancer cell lines. However, cell proliferation returned to normal after two weeks of chronic inhibition, despite the continued suppression of MEK or ERK. In contrast, K-ras-suppressed tumor cells entered an irreversible senescent-like state following ERK pathway inhibition. MEK inhibition or ERK1/2 suppression caused activation of p38α in a K-ras-dependent manner. Inhibition or suppression of p38α prevented the recovery of K-ras mutant tumor cells during prolonged MEK inhibition. Conclusion: Oncogenic K-ras activates p38α to maintain cell proliferation during MEK inhibition. MEK-targeting therapeutics can create an acquired tumor cell dependency on p38α. Show more

DOI: 10.3233/CLO-2010-0521

Citation: Analytical Cellular Pathology, vol. 32, no. 4, pp. 245-257, 2010

Authors: Xu, Ruodan | Povlsen, Gro Klitgaard | Soroka, Vladislav | Bock, Elisabeth | Berezin, Vladimir

Article Type: Research Article

Abstract: The epidermal growth factor family of receptor tyrosine kinases (ErbBs) plays essential roles in tumorigenesis and cancer disease progression, and therefore has become an attractive target for structure-based drug design. ErbB receptors are activated by ligand-induced homo- and heterodimerization. Structural studies have revealed that ErbB receptor dimers are stabilized by receptor–receptor interactions, primarily mediated by a region in the second extracellular domain, termed the “dimerization arm”. The present study is the first biological characterization of a peptide, termed Inherbin3, which constitutes part of the dimerization arm of ErbB3. Inherbin3 binds to the extracellular domains of all four ErbB receptors, with …the lowest peptide binding affinity for ErbB4. Inherbin3 functions as an antagonist of epidermal growth factor (EGF)-ErbB1 signaling. We show that Inherbin3 inhibits EGF-induced ErbB1 phosphorylation, cell growth, and migration in two human tumor cell lines, A549 and HN5, expressing moderate and high ErbB1 levels, respectively. Furthermore, we show that Inherbin3 inhibits tumor growth in vivo and induces apoptosis in a tumor xenograft model employing the human non-small cell lung cancer cell line A549. The Inherbin3 peptide may be a useful tool for investigating the mechanisms of ErbB receptor homo- and heterodimerization. Moreover, the here described biological effects of Inherbin3 suggest that peptide-based targeting of ErbB receptor dimerization is a promising anti-cancer therapeutic strategy. Show more

Keywords: ErbB receptor, peptide mimetics, tumor cell proliferation and migration, tumor growth, apoptosis

DOI: 10.3233/CLO-2010-0515

Citation: Analytical Cellular Pathology, vol. 32, no. 4, pp. 259-274, 2010

Authors: Hermsen, Mario A. | Sevilla, María A. | Llorente, José Luis | Weiss, Marjan M. | Grimbergen, Anneliese | Allonca, Eva | Garcia-Inclán, Cristina | Balbín, Milagros | Suárez, Carlos

Article Type: Research Article

Abstract: Background: Head and neck paraganglioma (PGL) are benign tumors that can cause important direct or surgery induced morbidity. Almost all familial and 11–29% of sporadic PGL are caused by inactivating germline mutations in succinate dehydrogenase (SDH) genes. Our aim was to screen for such mutations and to evaluate clinical parameters as predictors of germline mutation. Methods: Seventy-four PGL patients were analyzed for germline mutations and large deletions in SDH genes, VHL and RET. Results were correlated to clinical characteristics including gender, age, tumor localization and multifocality. The surgical approach was evaluated in terms of tumor origin, sequelae and subsequent …evolution. Results: Mutations in SDHB and SDHD were identified in equal proportion in 13/13 (100%) of familial and in 15/61 (25%) of sporadic cases. Familiarity, age ≤50 years and male gender were predictors of any germline mutation, while multifocality and carotid/vagal localization were indicative of SDHD mutation in particular. Conclusion: In contrast to other series, this cohort of Spanish patients showed many SDHB mutations. Sporadic cases with germline mutation are frequent and underline the importance of mutational screening of all PGL patients, allowing the identification of relatives at risk and the early diagnosis of the disease, reducing or avoiding morbidity. Show more

Keywords: Paraganglioma, SDH, mutation, large deletion, genetic screening

DOI: 10.3233/CLO-2009-0498

Citation: Analytical Cellular Pathology, vol. 32, no. 4, pp. 275-283, 2010

Authors: Di Fazio, Pietro | Schneider-Stock, Regine | Neureiter, Daniel | Okamoto, Kinya | Wissniowski, Till | Gahr, Susanne | Quint, Karl | Meissnitzer, Matthias | Alinger, Beate | Montalbano, Roberta | Sass, Gabriele | Hohenstein, Bernd | Hahn, Eckhart G. | Ocker, Matthias

Article Type: Research Article

Abstract: Inhibition of deacetylases represents a new treatment option for human cancer diseases. We applied the novel and potent pan-deacetylase inhibitor panobinostat (LBH589) to human hepatocellular carcinoma models and investigated by which pathways tumor cell survival is influenced. HepG2 (p53wt) and Hep3B (p53null) responded to panobinostat treatment with a reduction of cell proliferation and a significant increase in apoptotic cell death at low micromolar concentrations. Apoptosis was neither mediated by the extrinsic nor the intrinsic pathway but quantitative RT-PCR showed an upregulation of CHOP, a marker of the unfolded protein response and endoplasmic reticulum stress with subsequent activation of caspase …12. Dependent on the p53 status, a transcriptional upregulation of p21cip1/waf1 , an increased phosphorylation of H2AX, and an activation of the MAPK pathway were observed. In a subcutaneous xenograft model, daily i.p. injections of 10 mg/kg panobinostat lead to a significant growth delay with prolonged overall survival, mediated by reduced tumor cell proliferation, increased apoptosis and reduced angiogenesis in tumor xenografts. Panobinostat increased the acetylation of histones H3 and H4. Panobinostat is a well tolerated new treatment option for HCC that activates alternative pathways of apoptosis, also in p53-deficient tumors. Show more

Keywords: p21^cip1/waf1, unfolded protein response (UPR), endoplasmic reticulum stress, caspase 12, transcriptional regulation, xenograft model, HDAC, LBH589

DOI: 10.3233/CLO-2010-0511

Citation: Analytical Cellular Pathology, vol. 32, no. 4, pp. 285-300, 2010

Authors: Claessen, Marian M.H. | Schipper, Marguerite E.I. | Oldenburg, Bas | Siersema, Peter D. | Offerhaus, G. Johan A. | Vleggaar, Frank P.

Article Type: Research Article

Abstract: Objectives: The Wnt-pathway dominates the sporadic carcinogenesis whereas p53 plays a pivotal role in the colitis-associated counterpart. The expression of Wnt-signaling proteins and p53 during colitis-associated carcinogenesis was determined. Methods: A tissue microarray was constructed with colonic samples from 5 groups of patients: controls (C, n=10), IBD without neoplasia (IBD, n=12), non-dysplastic IBD with neoplasia elsewhere in the colon (IBD-NE, n=12), dysplastic lesion in IBD (IBD-DYS, n=12), and IBD-associated colorectal cancer (IBD-CRC, n=10). Immunohistochemistry was performed for β-catenin, cyclin D1 and p53. p53 sequence analysis was performed in some cases. Results: Nuclear β-catenin expression was found in 0%, …0%, 50%, 55% and 100% of the patients in the C-, IBD-, IBD-NE-, IBD-DYS- and IBD-CRC-groups, respectively. Non-dysplastic IBD mucosa with neoplasia detected elsewhere showed nuclear expression in 50% of the cases compared to 0% in IBD mucosa without neoplasia (p=0.02). Cyclin D1 staining had similar expression patterns. Overexpression of p53 was only detected in the IBD-DYS (66.7%) and IBD-CRC groups (50%). Conclusion: In contrast to previous findings, our results suggest activation of the Wnt-pathway in the early phase of colitis-associated carcinogenesis. Furthermore, as Wnt activation was observed in 50% of the IBD-NE cases, nuclear β-catenin may facilitate detection of neoplasia. Show more

Keywords: Colorectal cancer, inflammatory bowel disease, Wnt-pathway, surveillance, p53

DOI: 10.3233/CLO-2009-0503

Citation: Analytical Cellular Pathology, vol. 32, no. 4, pp. 303-310, 2010

Authors: Moelans, Cathy B. | de Weger, Roel A. | van Diest, P.J.

Article Type: Other

DOI: 10.3233/CLO-2009-0502

Citation: Analytical Cellular Pathology, vol. 32, no. 4, pp. 311-312, 2010