Sonia Rodriguez
Indiana University
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Featured researches published by Sonia Rodriguez.
Experimental Hematology | 2008
Luis Fernandez; Sonia Rodriguez; Hui Huang; Angelo Ferreira Chora; Jacquenilson Fernandes; Christin Mumaw; Eugenia Cruz; Karen E. Pollok; Filipa Cristina; Joanne E. Price; Michael J. Ferkowicz; David T. Scadden; Matthias Clauss; Angelo A. Cardoso; Nadia Carlesso
OBJECTIVE Homeostasis of the hematopoietic compartment is challenged and maintained during conditions of stress by mechanisms that are poorly defined. To understand how the bone marrow (BM) microenvironment influences hematopoiesis, we explored the role of Notch signaling and BM endothelial cells in providing microenvironmental cues to hematopoietic cells in the presence of inflammatory stimuli. MATERIALS AND METHODS The human BM endothelial cell line (BMEC) and primary human BM endothelial cells were analyzed for expression of Notch ligands and the ability to expand hematopoietic progenitors in an in vitro coculture system. In vivo experiments were carried out to identify modulation of Notch signaling in BM endothelial and hematopoietic cells in mice challenged with tumor necrosis factor-alpha (TNF-alpha) or lipopolysaccharide (LPS), or in Tie2-tmTNF-alpha transgenic mice characterized by constitutive TNF-alpha activation. RESULTS BM endothelial cells were found to express Jagged ligands and to greatly support progenitors colony-forming ability. This effect was markedly decreased by Notch antagonists and augmented by increasing levels of Jagged2. Physiologic upregulation of Jagged2 expression on BMEC was observed upon TNF-alpha activation. Injection of TNF-alpha or LPS upregulated three- to fourfold Jagged2 expression on murine BM endothelial cells in vivo and resulted in increased Notch activation on murine hematopoietic stem/progenitor cells. Similarly, constitutive activation of endothelial cells in Tie2-tmTNF-alpha mice was characterized by increased expression of Jagged2 and by augmented Notch activation on hematopoietic stem/progenitor cells. CONCLUSIONS Our results provide the first evidence that BM endothelial cells promote expansion of hematopoietic progenitor cells by a Notch-dependent mechanism and that TNF-alpha and LPS can modulate the levels of Notch ligand expression and Notch activation in the BM microenvironment in vivo.
Blood | 2011
Sonia Rodriguez; Lin Wang; Christen Mumaw; Edward F. Srour; Christina Lo Celso; Keiichi I. Nakayama; Nadia Carlesso
Exit from quiescence and reentry into cell cycle is essential for HSC self-renewal and regeneration. Skp2 is the F-box unit of the SCF E3-ligase that targets the CDK inhibitors (CKIs) p21(Cip1), p27(Kip1), p57(Kip2), and p130 for degradation. These CKIs inhibit the G(1) to S-phase transition of the cell cycle, and their deletion results in increased cell proliferation and decreased stem cell self-renewal. Skp2 deletion leads to CKIs stabilization inducing cell-cycle delay or arrest, and conversely, increased Skp2 expression is often found in cancers. Here, we show that SKP2 expression is increased in HSC and progenitors in response to hematopoietic stress from myelosuppression or after transplantation. At steady state, SKP2 deletion decreased the mitotic activity of HSC and progenitors resulting in enhanced HSC quiescence, increased HSC pool size, and maintenance. However, the inability to rapidly enter cell cycle greatly impaired the short-term repopulating potential of SKP2 null HSC and their ability to regenerate after myeloablative stress. Mechanistically, deletion of SKP2 in HSC and progenitors stabilized CKIs in vivo, particularly p27(Kip1), p57(Kip2), and p130. Our results demonstrate a previously unrecognized role for SKP2 in regulating HSC and progenitor expansion and hematopoietic regeneration after stress.
Stem cell reports | 2016
Huajia Zhang; Sonia Rodriguez; Lin Wang; Soujuan Wang; Henrique Serezani; Reuben Kapur; Angelo A. Cardoso; Nadia Carlesso
Summary Toll-like receptor 4 (TLR4) plays a central role in host responses to bacterial infection, but the precise mechanism(s) by which its downstream signaling components coordinate the bone marrow response to sepsis is poorly understood. Using mice deficient in TLR4 downstream adapters MYD88 or TRIF, we demonstrate that both cell-autonomous and non-cell-autonomous MYD88 activation are major causes of myelosuppression during sepsis, while having a modest impact on hematopoietic stem cell (HSC) functions. In contrast, cell-intrinsic TRIF activation severely compromises HSC self-renewal without directly affecting myeloid cells. Lipopolysaccharide-induced activation of MYD88 or TRIF contributes to cell-cycle activation of HSC and induces rapid and permanent changes in transcriptional programs, as indicated by persistent downregulation of Spi1 and CebpA expression after transplantation. Thus, distinct mechanisms downstream of TLR4 signaling mediate myelosuppression and HSC exhaustion during sepsis through unique effects of MyD88 and TRIF.
Cancer Research | 2017
Clara Mayo-de las Casas; Mónica Garzón; Nuria Jordana Ariza; Ariadna Balada; Jordi Bertran-Alamillo; Beatriz García; Sergio Villatoro; Erika Aldeguer; Sonia Rodriguez; Raquel Campos; Santiago Viteri Ramirez; María González-Cao; Niki Karachaliou; Rafael Rosell Costa; Miguel Angel Molina-Vila
Background: Stand alone tests such as PCR-derived techniques, FISH or IHC are usually employed to determine clinically relevant alterations in non-small cell lung cancer (NSCLC). However, they target single genes and proteins. Mutiplex techniques can reduce the turnaround time and quantity of sample in this setting, but require a careful validation. Methods: A total of 41 cfDNA samples from serum and plasma from advanced NSCLC p were analyzed with the Actionable Insights Tumor Panel, which covers mutations in 15 clinically relevant genes, using the Gene Reader platform (Qiagen). The samples had been previously genotyped for EGFR, KRAS and BRAF mutations by stand alone, PNA-Taqman assays. Paired biopsies were available in 37 cases. The remaining 4 corresponded to p.T790M-positive blood samples of p progressing to EGFR TKIs. Results: Of the 41 samples taken into the GeneReader workflow, some had a DNA input concentration below specifications, in spite of this limitation, good results were obtained. 14 mutations were fully concordant between tissue, Taqman and GeneReader and the four p.T790M mutations were concordant between Taqman and GeneReader. Five mutations present in tissue were detected by GeneReader and not by Taqman and 11 mutations detected by Taqman were below the 1% detection threshold of GeneReader. Finally, 12 mutations present in tissue were not detected in cfDNA by any of the assays. Concordance between the stand alone tests and the Gene Reader in cfDNA was 64%, raising to 84% if mutations Conclusions: Application of NGS to liquid biopsies is challenging and requires a careful validation. However, once fully validated, NGS will probably become the methodology of choice for cfDNA analysis in NSCLC patients at presentation and at progression. Citation Format: Clara Mayo de las Casas, Monica Garzon, Nuria Jordana Ariza, Ariadna Balada, Jordi Bertran-Alamillo, Beatriz Garcia, Sergio Villatoro, Erika Aldeguer, Sonia Rodriguez, Raquel Campos, Santiago Viteri Ramirez, Maria Gonzalez-Cao, Niki Karachaliou, Rafael Rosell Costa, Miguel Angel Molina-Vila. Next generation sequencing of circulating-free DNA from advanced non small cell lung cancer patients using Gene Reader® [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 5698. doi:10.1158/1538-7445.AM2017-5698
Cancer Research | 2017
Cristina Aguado; Cristina Teixidó; Ana Giménez-Capitán; Maria de los Llanos Gil; Sonia Rodriguez; Santiago Viteri; Niki Karachaliou; Erika Aldeguer; Vicente Peg; Lidia Alonso; Miguel Angel Molina-Vila; Rafael Rosell
Background: Rearrangements in anaplastic lymphoma kinase (ALK) gene can be detected in 5-7% of EGFR and KRAS wild-type advanced NSCLC patients (p). Fluorescent in situ hybridization (FISH) and immunohistochemistry (IHC) are currently used for screening but are unable to identify the specific fusion partner and are unpractical to monitor clinical responses due to difficulty of obtaining rebiopsies. The RT-PCR technique has the potential to overcome this pitfall and allow patient monitorization in blood. Methods: A total of 405 formalin-fixed paraffin-embedded (FFPE) samples from advanced NSCLC were analyzed by ALK IHC (Ventana D5F3) and FISH (Vysis). Positive patients were confirmed by RT-PCR and submitted to Sanger in order to identify the variant. In a subset of 36 patients with EML4-ALK-rearranged tumors who were treated with crizotinib, fusion transcripts were analyzed by RT-PCR in mRNA purified from plasma and platelets and correlated with clinical response. Results: ALK IHC was analyzed in 405 NSCLC patients and 37 tested positive (9.1%) whereas 25 (7.7%) were identify as translocated by FISH (n=323). ALK fusion transcripts were analyzed by RT-PCR and a new fusion variant of ALK was identified. A total of 36 p benefited from crizotinib treatment, including the p with the new variant. Monitoring of EML4-ALK fusion transcripts in the plasma ad platelets of 35 ALK positive patients revealed a good correlation with clinical outcome to crizotinib treatment, with the fusion transcripts becoming undetectable in p with good clinical responses. Conclusions: Analysis of ALK fusion transcripts in mRNA purified from plasma and platelets can have a value in patients with no biopsy available and to monitor the course of the disease. Citation Format: Cristina Aguado, Cristina Teixido, Ana Gimenez-Capitan, Maria de los Llanos Gil, Sonia Rodriguez, Santiago Viteri, Niki Karachaliou, Erika Aldeguer, Vicente Peg, Lidia Alonso, Miguel Angel Molina-Vila, Rafael Rosell. Analysis of EML4-ALK fusion transcripts in plasma and platelets to monitor response to crizotinib in EML4-ALK positive non-small cell lung cancer patients (NSCLC) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 1739. doi:10.1158/1538-7445.AM2017-1739
Cancer Research | 2017
Ana Giménez-Capitán; Cristina Teixidó; Cristina Aguado; Sonia Rodriguez; Jordi Bertran-Alamillo; Josep Castellví; Zaira Yeste; Ana Isabel Padilla Pérez; Rafael Rosell; Miguel Angel Molina-Vila
Background: Activating alterations of the mesenchymal epithelial transition (MET) oncogene in NSCLC are potentially actionable with targeted MET inhibitors. MET exon 14 skipping mutations have been described in 3% of patients (p) in NSCLC,.Fluorescent in situ hybridization (FISH) and immunohistochemistry (IHC) are currently used for detecting MET amplification and overexpression, respectively, but are not useful to detect MET splicing variants. On the other hand, the reverse transcription-polymerase chain reaction (RT-PCR) technique has the potential to detect this actionable alteration. Methods: We designed and validated a custom set of 5´and 3´ primers to detect the MET exon 14 splicing variant by RT-PCR. RNA isolation from FFPE samples was performed with Roche High Pure FFPET RNA isolation kit and M-MLV Reverse Transcriptase enzyme was used in the RT-PCR. A panel of cell lines was initially employed to assess the performance of the technique. Subsequently, a total of 232 formalin-fixed paraffin-embedded (FFPE) samples from advanced NSCLC patients were analyzed. Of them, 15 were positive by RT-PCR (n=209) for the MET exon 14 variant. The bands corresponding to the splicing variant were submitted to Sanger sequencing. Results were compared with FISH (ZytoVision Dual Color probe Z-2087-200) and IHC (Ventana CONFIRM anti-Total c-MET (SP44)). Results: A total of 232 EGFR-wt advanced NSCLC p were analyzed by IHC and 42 (18.1%) were considered as positive (cut-off 3+≥ 50%). Regarding FISH, MET amplification was detected in 13 out of 58 p (22.4%) evaluable while the MET exon 14 skipping variant was detected in 15 (7.2%) out of 209 p . Unexpectedly, only three (21.4%) of the positive MET exon 14 skipping p by RT-PCR were positive for IHC. Finally, of the 15 MET exon 14 positive p, 5 were evaluable for FISH and none of them were positive for MET amplification. Conclusion: In our cohort of 232 EGFR-wt, advanced NSCLC p, the MET exon 14 skipping mutation had an incidence of 7.2% No correlation was found between the presence of the MET exon 14 variant by RT-PCR and MET overexpression or amplification. Detection of MET exon 14 alterations poses a challenge for diagnostic testing. Citation Format: Ana Gimenez-Capitan, Cristina Teixido, Cristina Aguado, Sonia Rodriguez, Jordi Bertran-Alamillo, Josep Castellvi, Zaira Yeste, Ana Perez, Rafael Rosell, Miguel Angel Molina-Vila. MET exon 14 skipping mutations in advanced non-small cell lung cancer (NSCLC) are not associated with MET amplification and overexpression [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2723. doi:10.1158/1538-7445.AM2017-2723
Cancer Research | 2017
Jordi Bertran-Alamillo; Miguel Angel Molina-Vila; Cristina Teixidó; Jordi Codony-Servat; Ana Giménez-Capitán; Carles Codony-Servat; Silvia García-Román; Erika Aldeguer; Sonia Rodriguez; Rafael Rosell
Background: Aberrant activity of the MET, FGFR1 and AXL receptors has been associated with the development of resistance to first, second and third generation EGFR tyrosine kinase inhibitors (TKI) in EGFR-mutated non-small cell lung cancer (NSCLC) patients. Methods: We obtained 6 resistant lines by treating EGFR-mutated (exon 19), TKI sensitive PC9 cells with increasing concentrations of gefitinib or erlotinib. The p.T790M resistance mutation emerged in two cell lines (GR1, GR4), which remained sensitive to osimertinib, a third generation EGFR TKI. Six new cell lines to resistant to “second line” osimertinib were generated from GR1 and GR4 by exposure to increasing concentrations of the inhibitor. Finally, six more cell lines resistant to “first line” osimertinib were derived from the PC9 parental cells. All resistant cell lines were genotyped for selected genes (including EGFR) and characterized for AXL, MET and FGFR1 expression and activation by Q-RT-PCR, immunohistochemistry and Western blotting. The effects of AXL (BGB324), MET (crizotinib, capmatinib) and FGFR1 (nindetanib) inhibitors on the parental and the 18 resistant cell lines were analyzed by MTT and, in some cases, by colony formation. AXL was stably silenced in some of the resistant cell lines. Results: All cell lines resistant to “first line” gefitinib, erlotinib and osimertinib maintained the exon 19 EGFR sensitizing mutation. In contrast, three of the resistant cell lines to “second line” osimertinib lost the exon 19 and the p.T790M mutations. In two more, the p.T790M dropped to low allelic fractions (1% and 0.03%). Regardless of the EGFR status, AXL overexpression was the most common event related to EGFR TKI resistance in our panel of 18 cell lines, with FGFR1 and MET overexpression or activation as less frequent events. In proliferation assays, the IC50 of the EGFR TKI resistant cell lines for BGB324 (AXL inhibitor) was indistinguishable from the IC50 of the parental, EGFR TKI sensitive cell line. Similar results were obtained in the case of capmatinib, crizotinib (MET inhibitors) and nintedanib (FGFR inhibitor). Stable silencing of AXL on some of the AXL-overexpressing resistant cell lines had no effects in terms of doubling times, morphology of cells or sensitivity to EGFR TKIs. In combination experiments, the effect of BGB and MET inhibitors was found to be additive. Conclusions: In tumor cell line models of acquired resistance to EGFR TKIs, overexpression or activation of AXL, MET and FGFR1 was not associated to sensitivity to single-agent treatment with AXL, MET or FGFR inhibitors. Multitargeted approaches might be more effective in this setting. Citation Format: Jordi Bertran-Alamillo, Miguel Angel Molina-VIla, Cristina Teixido, Jordi Codony-Servat, Ana Gimenez-Capitan, Carles Codony-Servat, Silvia Garcia-Roman, Erika Aldeguer, Sonia Rodriguez, Rafael Rosell. Tumor cells with acquired resistance to EGFR inhibitors and overexpression or activation of AXL, MET and FGFR1 are insensitive to single-agent treatment targeting AXL, MET or FGFR [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 3077. doi:10.1158/1538-7445.AM2017-3077
Cancer Research | 2016
Niki Karachaliou; Imane Chaib; Sara Pilotto; Jordi Codony; Xueting Cai; Xuefei Li; Ana Drozdowskyj; Carles Codony; Andrés Felipe Cardona; Guillermo Lopez-Vivanco; Alain Vergnenegre; Jose Miguel Sanchez; Mariano Provencio; Filippo De Marinis; Enric Carcereny; Noemi Reguart; Rosario García-Campelo; Silvia Marin; Cristina Teixidó; Isabella Sperduti; Sonia Rodriguez; Roger Estrada; Raimon Puig de la Bellacasa; Jose Luis Ramirez; Miguel Angel Molina-Vila; Caicun Zhou; Peng Cao; Patrick C. Ma; Trever G. Bivona; Rafael Rosell
Intrinsic or acquired resistance limits the clinical effectiveness of EGFR tyrosine kinase inhibitors (TKIs) for non-small cell lung cancer (NSCLC) patients (p) with EGFR mutations. One of the signaling mediators downstream of activated EGFR is signal transducer and activator of transcription 3 (STAT3). Not only does gefitinib not inhibit STAT3, but it also augments STAT3 tyrosine phosphorylation. EGFR blockade enriches lung cancer stem cells (CSCs) through NOTCH3-dependent signaling. A co-receptor of IL-6 (gp130) associates with Src and triggers activation of YAP and NOTCH. Our study is designed with three parallel objectives: firstly, to demonstrate that single EGFR TKI treatment cannot abrogate STAT3 and Src in EGFR mutant NSCLC cell lines; secondly, to examine whether the combination of gefitinib with compounds that target STAT3, (TPCA-1) and Src (saracatinib), suppresses the mechanisms of resistance; thirdly, to identify biomarkers in clinical tumor samples that may help us predict the outcome of EGFR TKIs and design effective combination therapies. Cell viability assay (MTT), western blotting, quantitative-real time PCR (qRT-PCR) and aldefluor assay-flow cytometry were used. We found that gefitinib increases pSTAT3 Y705 in PC-9 cells (that harbor the exon 19 deletion) in a time- and dose-dependent manner. Nine days after gefitinib treatment STAT3 mRNA level was significantly elevated. PC-9 cells showed dramatic increase in the fraction of ALDH+ cells upon treatment with gefitinib. TPCA-1 increased sensitivity to gefitinib in the PC-9 cells. Combination of gefitinib with TPCA-1 abrogated pSTAT3 Y705 but neither inhibited pPaxillin Y118 (Src induced) and pYAP S127 nor prevented the increment in the ALDH+ CSCs subpopulation. The triple combination of gefitinib, TPCA-1 and saracatinib was highly synergistic and abrogated pSTAT3 Y705, pPaxillin Y118 and pYAP S127. We performed qRT-PCR at baseline tumor samples of 64 EGFR mutant NSCLC p treated with first line EGFR TKIs and found that high expression of STAT3 and YAP were significantly correlated with shorter median progression-free survival (mPFS). mPFS was 9.6 months (m) (95% CI, 5.9 to 14.1) for p with low STAT3 and 18.4m (95% CI, 8.8 to 30.2) for p with high STAT3 mRNA expression (P Citation Format: Niki Karachaliou, Imane Chaib, Sara Pilotto, Jordi Codony, Xueting Cai, Xuefei Li, Ana Drozdowskyj, Carles Codony, Andres Felipe Cardona, Guillermo Lopez-Vivanco, Alain Vergnenegre, Jose Miguel Sanchez, Mariano Provencio, Filippo de Marinis, Enric Carcereny, Noemi Reguart, Rosario Garcia-Campelo, Silvia Marin, Cristina Teixido, Isabella Sperduti, Sonia Rodriguez, Roger Estrada, Raimon Puig de la Bellacasa, Jose Luis Ramirez, Miguel Angel Molina-Vila, Caicun Zhou, Peng Cao, Patrick Ma, Trever Bivona, Rafael Rosell. Cotargeting EGFR, STAT3 and Src-Notch pathways: a promising approach to improve the efficacy of EGFR-TKIs in the treatment of NSCLC patients. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 265.
Cancer Research | 2016
Cristina Teixidó; Noemi Reguart; Ana Giménez-Capitán; Miguel Angel Molina-Vila; Patricia Galván; Sonia Rodriguez; Laia Paré; Santiago Viteri; Vicente Peg; Zaira Yeste; Nuria Viñolas; Rafael Rosell; Aleix Prat
Background: Targetable rearrangements in anaplastic lymphoma kinase (ALK), ROS1, and RET genes are present in approximately 7% of patients (p) with advanced NSCLC. Current methods for detecting gene fusions are based on FISH (FDA-approved companion diagnostic test for ALK), immunohistochemistry (IHC) or RT-PCR. However, these tests have disadvantages in terms of sensitivity, cost and throughput, and often show discrepancies. The nCounter platform allows simultaneous detection with no enzymatic reaction, within 72 hours, of several fusion genes in formalin-fixed paraffin-embedded (FFPE) samples using a transcript-based method. Methods: A custom set of 5′and 3′ probes and fusion-specific probes to detect ALK, ROS1 and RET fusion transcripts was designed and evaluated. A panel of ALK-ROS1-RET positive cell lines (H2228, H3122 [EML4-ALK], SUDHL-1 [NPM-ALK], HCC78 [SLC34A2-ROS1], BaF3 pBABE [CD74-ROS1], LC2/ad [RET]) and negative cell lines (PC9, H1975 [EGFR mut], H460, H23 [KRAS mut]) was used to validate the technique. Then, a total of 70 FFPE samples was analyzed, 49 of them positive by FISH, IHC and/or qRT-PCR for ALK (n = 30), ROS1 (n = 17) and RET (n = 2). Total RNA was isolated from cell lines and FFPE and 2.0 and ≤ 2.0 respectively or/and (2) a signal for a fusion-specific probe above background. Response to crizotinib by RECIST criteria was retrospectively collected in p with ALK-positive NSCLC by any technique. Results: nCounter sensitivity to detect fusion transcripts ALK, ROS1 and RET in cell lines was 100% using the two criteria (3’/5’ and direct probes) and specificity was also 100%. Among 20 ALK-FISH-positive p, ALK 3’-5’ scoring was positive in 18 (95%). One p was non-evaluable (NE) by ALK 3’-5’ scoring. Among 48 ALK-FISH-negative p, nCounter score was positive in 13 (27%). All p positive for ALK by nCounter were either positive or NE for ALK by IHC. A total of 17 p were treated with crizotinib, 16 of whom responded to treatment and were positive by nCounter. Regarding FISH, five p responding to crizotinib were negative and one was NE. Finally, one p not responding to crizotinib was positive by RT-PCR but negative by nCounter. Conclusion: The ALK/ROS1/RET nCounter-based assay is a highly sensitive screening assay that identifies ALK-FISH-negative/NE NSCLC patients who could benefit from treatment with ALK inhibitors. Citation Format: Cristina Teixido, Noemi Reguart, Ana Gimenez-Capitan, Miguel Angel Molina-Vila, Patricia Galvan, Sonia Rodriguez, Laia Pare, Santiago Viteri, Vicente Peg, Zaira Yeste, Nuria Vinolas, Rafael Rosell, Aleix Prat. Comparison of nCounter, immunohistochemistry, RT-PCR and FISH to detect ALK, ROS1 and RET rearrangements in advanced non-small cell lung cancer (NSCLC). [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4344.
Cancer Research | 2015
Rossella Rota; Laura Adesso; Beatrice Conti; Roberta Ciarapica; Lavinia Raimondi; Maria De Salvo; Sonia Rodriguez; Nadia Carlesso; Lucio Miele; Franco Locatelli
Background: Rhabdomyosarcoma (RMS) in a pediatric tumor of myogenic origin. It includes two subtypes: embryonal and alveolar. Embryonal RMS (ERMS) cells express key myogenic factors such as MyoD and Myogenin, but proliferate indefinitely and have lost the ability to terminally differentiate into skeletal myofibers. Differently from the alveolar tumors bearing specific chromosomal translocations, ERMS has cytogenetic aberrations and molecular deregulations of pathways regulating senescence, proliferation and differentiation. It has been shown that SKP2, an F-box protein and a component of the ubiquitin protein ligase complex SCFs (SKP1-cullin-F-box), is over-expressed in RMS primary samples and correlates with a dismal outcome. Therefore, we sought here to investigate the regulation of SKP2 and its role in ERMS. Methods: We modulated SKP2 expression through silencing, by using a siRNA validated in the literature, and forcing its expression through retroviral infection. In parallel, we investigate the effect of Notch signaling modulation on SKP2 expression. Results: SKP2 silencing resulted in cell cycle slowdown in both normal myoblasts and ERMS cells. Down-regulation of Notch1 led to SKP2 reduction while that of Notch3 supported SKP2 expression. Cosilencing SKP2 and Notch3 gave raise to myoblast-like structure formation in ERMS and facilitated myoblasts fusion. Finally, using a SKP2 inhibitor ERMS cell proliferation was completely blocked. Conclusion: Altogether, these preliminary experiments suggest that SKP2 could be regulated by Notch signaling in ERMS and that its inhibition hampers tumor cell proliferative capability. Note: This abstract was not presented at the meeting. Citation Format: Rossella Rota, Laura Adesso, Beatrice Conti, Roberta Ciarapica, Lavinia Raimondi, Maria De Salvo, Sonia Rodriguez, Nadia Carlesso, Lucio Miele, Franco Locatelli. SKP2 supports cell proliferation and is regulated by Notch signaling in myoblasts and embryonal rhabdomyosarcoma. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 3792. doi:10.1158/1538-7445.AM2015-3792