Time filter

Source Type

Vanacker L.,Laboratory of Molecular Oncology | Smeets D.,Flemish Institute for Biotechnology | Smeets D.,Catholic University of Leuven | Teugels E.,Laboratory of Molecular Oncology | And 5 more authors.
Anticancer Research | Year: 2014

Background/Aim: We report a case of a mixed adenoneuroendocrine carcinoma developed in a colorectal adenocarcinoma with lymph node and liver metastases exclusively emanating from the neuroendocrine carcinoma component. The patient underwent right hemicolectomy and postoperatively received chemotherapy with cisplatin and etoposide and subsequent high-dose induction chemotherapy, followed by autologous stem cell transplantation. Following this treatment, there was a complete remission. Currently, thirthy months after treatment, the patient is in unmaintained complete remission. Comparative exome sequencing of germline DNA and DNA from the two separate malignant components revealed six somatic changes in cancer consensus genes. Both components shared somatic mutations in Adenomatous polyposis coli (APC), Kirsten rat sarcoma viral oncogene homolog (KRAS), B-cell CLL/lymphoma 9 (BCL9) and Forkhead Box P1 (FOXP1) genes. Mutation in SWI/SNF related, matrix associated, actin dependent regulator of chromatin, subfamily a, member 4 (SMARCA4 ) was only found in the neuroendocrine carcinoma component. The finding of several identical somatic mutations in both components supports a clonal relationship between the neuroendocrine carcinoma and the adenocarcinoma. We suggest that a mutation in SMARCA4 could be responsible for the transformation of the adenocarcinoma component into the neuroendocrine phenotype. © 2014, International Institute of Anticancer Research. All rights reserved.


Laine A.,Åbo Akademi University | Laine A.,University of Turku | Sihto H.,Laboratory of Molecular Oncology | Come C.,Åbo Akademi University | And 18 more authors.
Cancer Discovery | Year: 2013

Senescence induction contributes to cancer therapy responses and is crucial for p53-mediated tumor suppression. However, whether p53 inactivation actively suppresses senescence induction has been unclear. Here, we show that E2F1 overexpression, due to p53 or p21 inactivation, promotes expression of human oncoprotein CIP2A, which in turn, by inhibiting PP2A activity, increases stabilizing serine 364 phosphorylation of E2F1. Several lines of evidence show that increased activity of E2F1-CIP2A feedback renders breast cancer cells resistant to senescence induction. Importantly, mammary tumorigenesis is impaired in a CIP2A-defi cient mouse model, and CIP2A-defi cient tumors display markers of senescence induction. Moreover, high CIP2A expression predicts for poor prognosis in a subgroup of patients with breast cancer treated with senescence-inducing chemotherapy. Together, these results implicate the E2F1-CIP2A feedback loop as a key determinant of breast cancer cell sensitivity to senescence induction. This feedback loop also constitutes a promising prosenescence target for therapy of cancers with an inactivated p53-p21 pathway. SIGNIFICANCE: It has been recently realized that most currently used chemotherapies exert their therapeutic effect at least partly by induction of terminal cell arrest, senescence. However, the mechanisms by which cell-intrinsic senescence sensitivity is determined are poorly understood. Results of this study identify the E2F1-CIP2A positive feedback loop as a key determinant of breast cancer cell sensitivity to senescence and growth arrest induction. Our data also indicate that this newly characterized interplay between 2 frequently overexpressed oncoproteins constitutes a promising prosenescence target for therapy of cancers with inactivated p53 and p21. Finally, these results may also facilitate novel stratifi cation strategies for selection of patients to receive senescence-inducing cancer therapies. © 2013 American Association for Cancer Research.


Sihto H.,Laboratory of Molecular Oncology | Sihto H.,University of Helsinki | Kukko H.,University of Helsinki | Koljonen V.,University of Helsinki | And 4 more authors.
Clinical Cancer Research | Year: 2011

Purpose: Merkel cell carcinoma (MCC) is rare skin cancer that is often associated with Merkel cell polyomavirus (MCPyV) infection. Polyomaviruses repress tumor suppressor proteins, thus influencing cell-cycle progression, but the effect of MCPyV on the key cell-cycle regulating proteins is poorly understood. Experimental Design: We evaluated expression of the MCPyV large T-antigen (LTA), Ki-67, and the key putative tumor suppressor proteins, the retinoblastoma protein (RB and phospho-RB) and p53, and their regulatory proteins (cyclin D1, cyclin E, p16, p21, p27, and MDM2) by using immunohistochemistry from tumors of 91 MCC patients identified from a population-based nationwide cohort. Tumor MCPyV DNA was measured by using quantitative PCR, and TP53 mutations were identified with sequencing. Results: MCPyV LTA expression was strongly associated with presence of MCPyV DNA in tumor, and it was almost invariably associated with tumor RB expression (P < 0.0001 for both comparisons). Both MCC LTA and RB expression were strongly associated with favorable MCC-specific and overall survival in univariable analyses (P ≤ 0.01 for all four analyses). Presence of MCPyV LTA was also associated with the female gender, the intermediate type of tumor histology, location of the tumor in a limb, cell proliferation rate, and absence of p53 expression. TP53 mutations were detected only in MCPyV DNA-negative tumors. Conclusions: MCPyV DNA-positive MCC has several clinical and molecular features that differ from MCPyV DNA-negative cancers. MCPyV-associated MCCs express RB, but may not harbor TP53 mutations. These findings provide further support that MCPyV causes the majority of MCCs. ©2011 AACR.


Waltari M.,Laboratory of Molecular Oncology | Waltari M.,University of Helsinki | Sihto H.,Laboratory of Molecular Oncology | Sihto H.,University of Helsinki | And 6 more authors.
International Journal of Cancer | Year: 2011

Most Merkel cell carcinomas (MCCs) contain Merkel cell polyomavirus (MCPyV) DNA, and the virus likely has a pivotal role in tumor pathogenesis. p53 and the KIT receptor tyrosine kinase have also been implicated in MCC pathogenesis, but little is known about their association with MCPyV infection. We identified 207 patients diagnosed with MCC in Finland in 1979-2004 and reviewed the histological diagnoses. Adequate clinical information, tumor tissue and DNA were available from 87 confirmed MCC cases. Presence of MCPyV DNA was assessed using quantitative PCR; p53, KIT, phospho-KIT, stem cell factor (SCF) and PDGFRα expression using immunohistochemistry and presence of mutations in KIT exons 9, 11, 13 and 17 and PDGFRA exons 10, 12, 14 and 18 using DNA sequencing. Most (77.0%) of the 87 tumors contained MCPyV DNA and 37 (42.5%) expressed KIT, whereas PDGFRα, p53, SCF and pKIT expression was less common (31.9, 22.8, 8.6 and 4.8%, respectively). No KIT or PFGFRA mutations were detected, but 10 (12.5%) of the 80 tumors studied harbored common PDGFRA exon 10 S478P substitution. Tumor p53 and KIT expression were associated with absence of MCPyV DNA (p = 0.01 and 0.009, respectively). Tumor p53 expression was associated with unfavorable MCC-specific survival (p = 0.021) and overall survival (p = 0.046), but tumor KIT expression only when stratified by presence of MCPyV DNA. The results suggest that p53 and KIT expression are associated with absence of MCPyV DNA in MCC, and that the molecular pathogenesis of MCC is multifactorial. Copyright © 2010 UICC.


PubMed | University of Lausanne, Laboratory of Cancer Genomics, Laboratory of Molecular Oncology and National Research Council Italy
Type: Journal Article | Journal: Oncotarget | Year: 2016

Adenocarcinomas of the prostate arise as multifocal heterogeneous lesions as the likely result of genetic and epigenetic alterations and deranged cell-cell communication. Notch signaling is an important form of intercellular communication with a role in growth/differentiation control and tumorigenesis. Contrasting reports exist in the literature on the role of this pathway in prostate cancer (PCa) development. We show here that i) compared to normal prostate tissue, Notch1 expression is significantly reduced in a substantial fraction of human PCas while it is unaffected or even increased in others; ii) acute Notch activation both inhibits and induces process networks associated with prostatic neoplasms; iii) down-modulation of Notch1 expression and activity in immortalized normal prostate epithelial cells increases their proliferation potential, while increased Notch1 activity in PCa cells suppresses growth and tumorigenicity through a Smad3-dependent mechanism involving p21WAF1/CIP1; iv) prostate cancer cells resistant to Notch growth inhibitory effects retain Notch1-induced upregulation of pro-oncogenic genes, like EPAS1 and CXCL6, also overexpressed in human PCas with high Notch1 levels. Taken together, these results reconcile conflicting data on the role of Notch1 in prostate cancer.


Krajc M.,Institute of Oncology Ljubljana | Zadnik V.,Institute of Oncology Ljubljana | Novakovic S.,Institute of Oncology Ljubljana | Stegel V.,Institute of Oncology Ljubljana | And 6 more authors.
Clinical Genetics | Year: 2014

Knowledge of the geographical distribution of highly recurrent mutations may be useful for efficient screening in cancer families. Since the cloning of the BRCA1/2 genes, it is known that the wide spectrum of deleterious mutations shows high ethnic and geographic heterogeneity. In this study, we have tested probands from 582 breast/ovarian cancer families and positioned all 156 BRCA1/2 families on the map according to the family origin. We observed that high-risk families with the same recurrent mutation present a typical geographical distribution and that different recurrent mutations may show different distribution patterns. We then evaluated the genetic screening implications of this heterogeneous prevalence of the most recurrent mutations found [300T>G(c.181T>G), 1806C>T(c.1687C>T), 969ins7(c.844_850dupTCATTAC), 5382insC(c.5266dupC), 235G>A(c.116G>A) in BRCA1 and IVS16-2A>G(c.7806-2A>G) in BRCA2]. On the basis of these results, specific testing procedures for new incident cases may be offered according to their family origins and, according to the information regarding clusters revealed in this study, the individuals (especially those at low risk), originating from regions with clusters, might be screened preferentially for cluster mutations and analysis may be simplified according to the family origin. © 2013 John Wiley & Sons A/S.


Zennaro D.,Center for Molecular Allergology | Scala E.,Center for Molecular Allergology | Pomponi D.,Center for Molecular Allergology | Caprini E.,Laboratory of Molecular Oncology | And 4 more authors.
Clinical and Experimental Immunology | Year: 2012

Immune dysregulation, polyendocrinopathy, enteropathy, X-linked (IPEX) is a rare syndrome due to a mutation in the forkhead box protein 3 gene (FOXP3) leading to an impaired regulatory T cell (T reg) activity associated both with skewed T helper type 2 (Th2) response and autoreactive phenomena. The purpose of this study was to describe a combined proteomics and genomics approach to comprehensively evaluate clinical and immunological phenotypes of patients affected by IPEX. T cell receptor (TCR)-Vβ repertoire and peripheral blood lymphocytes phenotype from three brothers affected by IPEX were studied by flow cytometry. Specific immunoglobulin (Ig)E were evaluated by means of an allergenic molecules microarray [immuno solid-phase allergen chip (ISAC)]. Total RNA was extracted and hybridized to Affymetrix oligonucleotide arrays to obtain quantitative gene-expression levels. No FOXP3 protein was detectable within CD127 -CD25 highCD4 + T cells from peripheral blood. A T cell-naive phenotype (CD62L +CD45R0 -) associated with a reduction of both CD26 and CD7 expression and a TCR-Vβ 8 and 22 family expansions were found. B lymphocytes were mainly CD5 + (B1) cells expressing a naive phenotype (tcl1 +CD27 -). The three IPEX patients had severe food allergy and specific IgE reactivity to cow's milk allergens, a hen's egg allergen and a wheat allergen. Gene expression profile analysis revealed a dysregulation associated mainly with Th1/Th2 pathways. The multiplexing evaluation reported in this study represents a comprehensive approach in the assessment of genetic conditions affecting the immune system such as the IPEX syndrome, paving the way for the development of diagnostic tools to improve the standard clinical and immunological profiling of the disease. © 2011 The Authors. Clinical and Experimental Immunology © 2011 British Society for Immunology.


Stegel V.,Institute of Oncology Ljubljana | Krajc M.,Institute of Oncology Ljubljana | Zgajnar J.,Institute of Oncology Ljubljana | Teugels E.,Laboratory of Molecular Oncology | And 3 more authors.
BMC Medical Genetics | Year: 2011

Background: The BRCA1 and BRCA2 mutation spectrum and mutation detection rates according to different family histories were investigated in 521 subjects from 322 unrelated Slovenian cancer families with breast and/or ovarian cancer.Methods: The BRCA1 and BRCA2 genes were screened using DGGE, PTT, HRM, MLPA and direct sequencing.Results: Eighteen different mutations were found in BRCA1 and 13 in BRCA2 gene. Mutations in one or other gene were found in 96 unrelated families. The mutation detection rates were the highest in the families with at least one breast and at least one ovarian cancer - 42% for BRCA1 and 8% for BRCA2. The mutation detection rate observed in the families with at least two breast cancers with disease onset before the age of 50 years and no ovarian cancer was 23% for BRCA1 and 13% for BRCA2. The mutation detection rate in the families with at least two breast cancers and only one with the disease onset before the age of 50 years was 11% for BRCA1 and 8% for BRCA2. In the families with at least two breast cancers, all of them with disease onset over the age of 50 years, the detection rate was 5% for BRCA2 and 0% for BRCA1.Conclusion: Among the mutations detected in Slovenian population, 5 mutations in BRCA1 and 4 mutations in BRCA2 have not been described in other populations until now. The most frequent mutations in our population were c.181T > G, c.1687C > T, c.5266dupC and c.844_850dupTCATTAC in BRCA1 gene and c.7806-2A > G, c.5291C > G and c.3978insTGCT in BRCA2 gene (detected in 69% of BRCA1 and BRCA2 positive families). © 2011 Stegel et al; licensee BioMed Central Ltd.


Sahi H.,University of Helsinki | Sahi H.,Toolo Hospital | Koljonen V.,University of Helsinki | Kavola H.,University of Helsinki | And 4 more authors.
Virchows Archiv | Year: 2012

Merkel cell carcinoma (MCC) is an aggressive dermal tumour of neuroendocrine origin. The recently found Merkel cell polyomavirus (MCV) integrates clonally in the tumour genome, which suggests an important role in the pathogenesis of the disease. Previous small-scale studies have detected anti-apoptotic protein bcl-2 in 80% of MCC tumours, but its correlation to the prognosis of MCC remains controversial. Our aim was to clarify the correlation of immunohistochemical expression of bcl-2 to MCV presence and MCC prognosis. We analyzed 116 primary MCC specimens with corresponding clinical data by immunohistochemistry for bcl-2. The presence of MCV DNA had been analyzed by quantitative PCR for 108 tumours. The correlations were analyzed statistically. Of the primary MCC samples, 85% were bcl-2 positive. No significant differences in MCV DNA occurred between the bcl-2-positive and bcl-2-negative tumours. Local and systemic metastasis was more common in patients with bcl-2 negative tumours (33%) than in patients with bcl-2-positive tumours (12%; p=0.04) at the time of diagnosis. The mean overall survival was higher in patients with bcl-2-positive tumours than of those with negative tumours (mean survival 1,814 days (5.0 years) vs. 769 days (2.1 years), p=0.01). Bcl-2 positivity indicates better clinical stage at the time of diagnosis and a longer survival in MCC. © Springer-Verlag 2012.


Shi Y.,Laboratory of Molecular Oncology | Felley-Bosco E.,Laboratory of Molecular Oncology | Marti T.M.,Laboratory of Molecular Oncology | Orlowski K.,University of Zürich | And 2 more authors.
BMC Cancer | Year: 2012

Background: Optimizing the safety and efficacy of standard chemotherapeutic agents such as cisplatin (CDDP) is of clinical relevance. Serum starvation in vitro and short-term food starvation in vivo both stress cells by the sudden depletion of paracrine growth stimulation.Methods: The effects of serum starvation on CDDP toxicity were investigated in normal and cancer cells by assessing proliferation, cell cycle distribution and activation of DNA-damage response and of AMPK, and were compared to effects observed in cells grown in serum-containing medium. The effects of short-term food starvation on CDDP chemotherapy were assessed in xenografts-bearing mice and were compared to effects on tumor growth and/or regression determined in mice with no diet alteration.Results: We observed that serum starvation in vitro sensitizes cancer cells to CDDP while protecting normal cells. In detail, in normal cells, serum starvation resulted in a complete arrest of cellular proliferation, i.e. depletion of BrdU-incorporation during S-phase and accumulation of the cells in the G0/G1-phase of the cell cycle. Further analysis revealed that proliferation arrest in normal cells is due to p53/p21 activation, which is AMPK-dependent and ATM-independent. In cancer cells, serum starvation also decreased the fraction of S-phase cells but to a minor extent. In contrast to normal cells, serum starvation-induced p53 activation in cancer cells is both AMPK- and ATM-dependent. Combination of CDDP with serum starvation in vitro increased the activation of ATM/Chk2/p53 signaling pathway compared to either treatment alone resulting in an enhanced sensitization of cancer cells to CDDP. Finally, short-term food starvation dramatically increased the sensitivity of human tumor xenografts to cisplatin as indicated not only by a significant growth delay, but also by the induction of complete remission in 60% of the animals bearing mesothelioma xenografts, and in 40% of the animals with lung carcinoma xenografts.Conclusion: In normal cells, serum starvation in vitro induces a cell cycle arrest and protects from CDDP induced toxicity. In contrast, proliferation of cancer cells is only moderately reduced by serum starvation whereas CDDP toxicity is enhanced. The combination of CDDP treatment with short term food starvation improved outcome in vivo. Therefore, starvation has the potential to enhance the therapeutic index of cisplatin-based therapy. © 2012 Shi et al.; licensee BioMed Central Ltd.

Loading Laboratory of Molecular Oncology collaborators
Loading Laboratory of Molecular Oncology collaborators