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Östermalm, Sweden

Lazzari C.,Regina Elena Cancer Institute | Prodosmo A.,Regina Elena Cancer Institute | Siepi F.,Regina Elena Cancer Institute | Rinaldo C.,Regina Elena Cancer Institute | And 8 more authors.
Oncogene | Year: 2011

Homeodomain-interacting protein kinase 2 (HIPK2) is an emerging player in cell response to genotoxic agents that senses damage intensity and contributes to the cell's choice between cell cycle arrest and apoptosis. Phosphorylation of p53 at S46, an apoptosis-specific p53 posttranslational modification, is the most characterized HIPK2 function in response to lethal doses of ultraviolet (UV), ionizing radiation or different anticancer drugs, such as cisplatin, roscovitine and doxorubicin (DOX). Indeed, like p53, HIPK2 has been shown to contribute to the effectiveness of these treatments. Interestingly, p53-independent mechanisms of HIPK2-induced apoptosis were described for UV and tumor growth factor-Β treatments; however, it is unknown whether these mechanisms are relevant for the responses to anticancer drugs. Because of the importance of the so-called 'p53-independent apoptosis and drug response' in human cancer chemotherapy, we asked whether p53-independent factor(s) might be involved in HIPK2-mediated chemosensitivity. Here, we show that HIPK2 depletion by RNA interference induces resistance to different anticancer drugs even in p53-null cells, suggesting the involvement of HIPK2 targets other than p53 in response to chemotherapy. In particular, we found that HIPK2 phosphorylates and promotes proteasomal degradation of ΔNp63α, a prosurvival ΔN isoform of the p53 family member, p63. Indeed, effective cell response to different genotoxic agents was shown to require phosphorylation-induced proteasomal degradation of ΔNp63α. In DOX-treated cells, we show that HIPK2 depletion interferes with ΔNp63α degradation, and expression of a HIPK2-resistant ΔNp63α-Δ390 mutant induces chemoresistance. We identify T397 as the ΔNp63α residue phosphorylated by HIPK2, and show that the non-phosphorylatable ΔNp63α-T397A mutant is not degraded in the face of either HIPK2 overexpression or DOX treatment. These results indicate ΔNp63α as a novel target of HIPK2 in response to genotoxic drugs. © 2011 Macmillan Publishers Limited All rights reserved.

Rinaldo C.,Regina Elena Cancer Institute | Luciani E.,St Andrea Universitary Hospital | Giacomelli L.,University of Rome La Sapienza | Bellotti C.,University of Rome La Sapienza | And 6 more authors.
PLoS ONE | Year: 2011

Background: Galectin-3 (Gal-3) is an anti-apoptotic molecule involved in thyroid cells transformation. It is specifically overexpressed in thyroid tumour cells and is currently used as a preoperative diagnostic marker of thyroid malignancy. Gal-3 expression is downregulated by wt-p53 at the transcriptional level. In well-differentiated thyroid carcinomas (WDTCs) there is an unexplained paradoxical concomitant expression of Gal-3 and wt-p53. HIPK2 is a co-regulator of different transcription factors, and modulates basic cellular processes mainly through the activation of wt-p53. Since we demonstrated that HIPK2 is involved in p53-mediated Gal-3 downregulation, we asked whether HIPK2 deficiency might be responsible for such paradoxical Gal-3 overexpression in WDTC. Methodology/Principal Findings: We analyzed HIPK2 protein and mRNA levels, as well as loss of heterozygosity (LOH) at the HIPK2 locus (7q32-34), in thyroid tissue samples. HIPK2 protein levels were high in all follicular hyperplasias (FHs) analyzed. Conversely, HIPK2 was undetectable in 91.7% of papillary thyroid carcinomas (PTCs) and in 60.0% of follicular thyroid carcinomas (FTCs). HIPK2 mRNA levels were upregulated in FH compared to normal thyroid tissue (NTT), while PTC showed mean HIPK2 mRNA levels lower than FH and, in 61.5% of cases, also lower than NTT. We found LOH at HIPK-2 gene locus in 37.5% of PTCs, 14.3% of FTCs and 18.2% of follicular adenomas. To causally link these data with Gal-3 upregulation, we performed in vitro experiments, using the PTC-derived K1 cells, in which HIPK2 expression was manipulated by RNA interference (RNAi) or plasmid-mediated overexpression. HIPK2 RNAi was associated with Gal-3 upregulation, while HIPK2 overexpression with Gal-3 downregulation. Conclusions/Significance: Our results indicate that HIPK2 expression and function are impaired in WDTCs, in particular in PTCs, and that this event explains Gal-3 overexpression typically observed in these types of tumours. Therefore, HIPK2 can be considered as a new tumour suppressor gene for thyroid cancers. © 2011 Lavra et al.

Bartolazzi A.,Cancer Center Karolinska | Bartolazzi A.,St Andrea University Hospital | Sciacchitano S.,St Andrea University Hospital | Sciacchitano S.,St Pietro Fatebenefratelli Hospital Research Center
Applied Immunohistochemistry and Molecular Morphology | Year: 2012

In the last decade, the β-galactosyl binding protein galectin-3 has been the object of extensive molecular, structural, and functional studies aimed to clarify its biological role in cancer. Multicenter studies also contributed to discover the potential clinical value of galectin-3 expression analysis in distinguishing, preoperatively, benign from malignant thyroid nodules. As a consequence galectin-3 is receiving significant attention as tumor marker for thyroid cancer diagnosis, but some conflicting results mostly owing to methodological problems have been published. The possibility to apply preoperatively a reliable galectin-3 test method on fine needle aspiration biopsy (FNA)-derived thyroid cells represents an important achievement. When correctly applied, the method reduces consistently the gray area of thyroid FNA cytology, contributing to avoid unnecessary thyroid surgery. Although the efficacy and reliability of the galectin-3 test method have been extensively proved in several studies, its translation in the clinical setting requires well-standardized reagents and procedures. After a decade of experimental work on galectin-3-related basic and translational research projects, the major methodological problems that may potentially impair the diagnostic performance of galectin-3 immunotargeting are highlighted and discussed in detail. A standardized protocol for a reliable galectin-3 expression analysis is finally provided. The aim of this contribution is to improve the clinical management of patients with thyroid nodules, promoting the preoperative use of a reliable galectin-3 test method as ancillary technique to conventional thyroid FNA cytology. The final goal is to decrease unnecessary thyroid surgery and its related social costs. © 2011 by Lippincott Williams & Wilkins.

Wang X.,Cancer Center Karolinska | Albertioni F.,Cancer Center Karolinska
Nucleosides, Nucleotides and Nucleic Acids | Year: 2010

Clofarabine, a new-generation purine nucleoside analogue, was thought to work via three mechanisms: incorporation into DNA; induction of apoptosis; and inhibition of ribonucleotide reductase, and showed significant efficacy in pediatric relapsed/refractory acute lymphoblastic leukemia (ALL) and hematologic malignancies in adults. By way of its unique metabolic properties, clofarabine is being explored in lymphoproliferative disorders and solid tumors. In this study, the effect of clofarabine on the DNA synthesis of human colon carcinoma cells (HCT116) was investigated by LigandTracer White which provides a simple and accurate method for investigating the uptake, phosphorylation, retention and DNA incorporation of nucleosides in cells. Clofarabine enters into HCT116 cells in a clearly detectable manner. At 100 nM, the interaction is visible and at 10 M a high signal is achieved and approaches equilibrium after 1∼2 hours. The thymidine incorporation into the DNA synthesis was rapidly stopped by incubation with 10 M clofarabine and a 3-fold increase in apoptosis induction in HCT116 cells by clofarabine was detected. Copyright © 2010 Taylor and Francis Group, LLC.

Ligtenberg M.A.,Cancer Center Karolinska | Rojas-Colonelli N.,Laboratory of Gene Immunotherapy | Rojas-Colonelli N.,Andres Bello University | Kiessling R.,Cancer Center Karolinska | And 2 more authors.
Human Vaccines and Immunotherapeutics | Year: 2013

DNA vaccines have been shown to elicit tumor-protective cytotoxic T lymphocyte (CTL) immunity in preclinical models, but have shown limited efficacy in cancer patients. Plasmids used for DNA vaccines can stimulate several innate immune receptors, triggering the activation of master transcription factors, including interferon regulatory factor 3 (IRF3) and nuclear factor k B (NF-kB). These transcription factors drive the production of type I interferons (IFNs) and pro-inflammatory cytokines, which promote the induction of CTL responses. Understanding the innate immune signaling pathways triggered by DNA vaccines that control the generation of CTL responses will increase our ability to design more effective vaccines. To gain insight into the contribution of these pathways, we vaccinated mice lacking different signaling components with plasmids encoding tyrosinase-related protein 2 (TRP2) or ovalbumin (OVA) using intradermal electroporation. Antigenspecific CTL responses were detected by intracellular IFN-7 staining and in vivo cytotoxicity. Mice lacking IRF3, IFN-a receptor, IL-1 p/IL-18, TLR9 or MyD88 showed similar CTL responses to wild-type mice, arguing that none of these molecules were required for the immunogenicity of DNA vaccines. To elucidate the role of NF-kB activation we co-vaccinated mice with pkBa-SR, a plasmid encoding a mutant IκBα that blocks NF-κB activity. Mice vaccinated with plκBα-SR and the TRP2-encoding plasmid (pTRP2) drastically reduced the frequencies of TRP2-specific CTLs and were unable to suppress lung melanoma metastasis in vivo, as compared with mice vaccinated only with pTRP2. Taken together these results indicate that the activation of NF-kB is essential for the immunogenicity of intradermal DNA vaccines. © 2013 Landes Bioscience.

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