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See detailOsteopontin predicts radiotherapy response of glioblastoma patients : new role in DNA damage repair
Henry, Aurélie ULg; Nokin, Marie-Julie; Leroi, Natacha ULg et al

Conference (2016, March 22)

- Introduction: Glioblastoma (GBM) is the most aggressive and common solid human brain tumor. Because of GBM heterogeneity, location and aggressiveness, none of the available treatment is curative. These ... [more ▼]

- Introduction: Glioblastoma (GBM) is the most aggressive and common solid human brain tumor. Because of GBM heterogeneity, location and aggressiveness, none of the available treatment is curative. These treatments include maximal surgical resection, radiotherapy and concomitant or adjuvant chemotherapy with Temozolomide. However, the prognosis of adult patients with GBM remains poor and the survival outcome after treatment does not exceed 15 months. GBM-composing cells have developed many strategies to counteract these current therapies. Among the wide hallmarks acquired to survive, high osteopontin (OPN) expression correlates with lower overall and disease-free/relapse-free survival in all tumors combined, as well in brain cancer. Our recent study (Lamour V and Henry A, IJC 2015) has demonstrated the role of OPN in the tumorigenicity of glioblastoma cells and its importance in the maintenance of the stem characters. In the continuation of this work, our recent studies focused on the potential role of OPN in the resistance of GBM cells to radiotherapy and its potential implication in the initiation of Double Strand Breaks (DSBs) repair mechanisms. - Aims: In the context of this study, different GBM cell lines (U251-MG, U87-MG and U87 Viii) were used to assess the role of OPN in the initiation of the DSBs repair mechanism after an exposure to gamma-irradiation. - Methods and results: We performed the transient transfection of different GBM cell lines (U251-MG, U87-MG and U87-MG overexpressing EGFR VIII) with siRNAs specifically directed against OPN. After irradiation, all these OPN-depleted cells consistently showed a lower induction of γ–H2AX compared to control (irrelevant siRNA) as evidenced by western blot and immunofluorescence techniques. Thereafter, clonogenic assays allowed to prove that the survival of OPN-depleted cells was affected after an exposure to irradiation. To assess the importance of OPN expression in the response to radiotherapy, an heterotopic xenograft model was used. In brief, IPTG-inducible U87 shOPN clones were injected subcutaneously in NOD-SCID mice and were allowed to form a tumor. When average tumor volume reached a predetermined size range, mice were treated (or not) with IPTG by intraperitoneal injection during five days. At the end of the treatment, tumors were selectively exposed to gamma-irradiation by using a small animal irradiator X-RAD 225Cx (Precision X-Ray Inc., North Branford, CT). One week later, mice were sacrificed and tumors were measured. In this pilot study, we observed that mice in which the tumor was depleted in OPN displayed a slight regression in the tumor growth compared to mice that received radiotherapy alone (no IPTG), where the tumor volume remained constant. - Conclusions: Taken together, these preliminary data meet the fact that OPN is important in the response of GBM to radiotherapy. The in vitro results converge to the fact that OPN might be implicated in the initiation of the DSBs repair following irradiation. Currently, we would like to investigate this hypothesis in vivo but also to check the effect of OPN depletion combined to radiotherapy on the survival of mice in an orthotopic xenograft model. [less ▲]

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See detailHDAC7 inhibition resets STAT3 tumorigenic activity in human glioblastoma independently of EGFR and PTEN: new opportunities for selected targeted therapies
Peixoto, Paul; Blomme, Arnaud; Costanza, Brunella ULg et al

in Oncogene (2016)

To date, the mutational status of EGFR and PTEN has been shown as relevant for favoring pro- or anti-tumor functions of STAT3 in human glioblastoma multiforme (GBM). We have screened genomic data from 154 ... [more ▼]

To date, the mutational status of EGFR and PTEN has been shown as relevant for favoring pro- or anti-tumor functions of STAT3 in human glioblastoma multiforme (GBM). We have screened genomic data from 154 patients and have identified a strong positive correlation between STAT3 and HDAC7 expression. In the current work we show the existence of a subpopulation of patients overexpressing HDAC7 and STAT3 that has particularly poor clinical outcome. Surprisingly, the somatic mutation rate of both STAT3 and HDAC7 was insignificant in GBM comparing with EGFR, PTEN or TP53. Depletion of HDAC7 in a range of GBM cells induced the expression of tyrosine kinase JAK1 and the tumor suppressor AKAP12. Both proteins synergistically sustained the activity of STAT3 by inducing its phosphorylation (JAK1) and protein expression (AKAP12). In absence of HDAC7, activated STAT3 was responsible for significant imbalance of secreted pro-/anti-angiogenic factors. This inhibited the migration and sprouting of endothelial cells in paracrine fashion in vitro as well as angiogenesis in vivo. In a murine model of GBM, induced HDAC7-silencing decreased the tumor burden by threefold. The current data show for the first time that silencing HDAC7 can reset the tumor suppressor activity of STAT3, independently of the EGFR/PTEN/TP53 background of the GBM. This effect could be exploited to overcome tumor heterogeneity and provide a new rationale behind the development of specific HDAC7 inhibitors for clinical use. [less ▲]

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See detailMyoferlin Regulates Endosomal Trafficking and Tunes Cancer Cell Metabolism
Blomme, Arnaud; Costanza, Brunella; Thiry, Marc ULg et al

Poster (2015, January 31)

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See detailMyoferlin regulates endosomal trafficking and tunes cancer cell metabolism
Blomme, Arnaud; Costanza, Brunella; Thiry, Marc ULg et al

Poster (2015, January 27)

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See detailAsporin Is a Fibroblast-Derived TGF-beta1 Inhibitor and a Tumor Suppressor Associated with Good Prognosis in Breast Cancer.
Maris, Pamela; Blomme, Arnaud; Palacios, Ana Perez et al

in PLoS medicine (2015), 12(9), 1001871

BACKGROUND: Breast cancer is a leading malignancy affecting the female population worldwide. Most morbidity is caused by metastases that remain incurable to date. TGF-beta1 has been identified as a key ... [more ▼]

BACKGROUND: Breast cancer is a leading malignancy affecting the female population worldwide. Most morbidity is caused by metastases that remain incurable to date. TGF-beta1 has been identified as a key driving force behind metastatic breast cancer, with promising therapeutic implications. METHODS AND FINDINGS: Employing immunohistochemistry (IHC) analysis, we report, to our knowledge for the first time, that asporin is overexpressed in the stroma of most human breast cancers and is not expressed in normal breast tissue. In vitro, asporin is secreted by breast fibroblasts upon exposure to conditioned medium from some but not all human breast cancer cells. While hormone receptor (HR) positive cells cause strong asporin expression, triple-negative breast cancer (TNBC) cells suppress it. Further, our findings show that soluble IL-1beta, secreted by TNBC cells, is responsible for inhibiting asporin in normal and cancer-associated fibroblasts. Using recombinant protein, as well as a synthetic peptide fragment, we demonstrate the ability of asporin to inhibit TGF-beta1-mediated SMAD2 phosphorylation, epithelial to mesenchymal transition, and stemness in breast cancer cells. In two in vivo murine models of TNBC, we observed that tumors expressing asporin exhibit significantly reduced growth (2-fold; p = 0.01) and metastatic properties (3-fold; p = 0.045). A retrospective IHC study performed on human breast carcinoma (n = 180) demonstrates that asporin expression is lowest in TNBC and HER2+ tumors, while HR+ tumors have significantly higher asporin expression (4-fold; p = 0.001). Assessment of asporin expression and patient outcome (n = 60; 10-y follow-up) shows that low protein levels in the primary breast lesion significantly delineate patients with bad outcome regardless of the tumor HR status (area under the curve = 0.87; 95% CI 0.78-0.96; p = 0.0001). Survival analysis, based on gene expression (n = 375; 25-y follow-up), confirmed that low asporin levels are associated with a reduced likelihood of survival (hazard ratio = 0.58; 95% CI 0.37-0.91; p = 0.017). Although these data highlight the potential of asporin to serve as a prognostic marker, confirmation of the clinical value would require a prospective study on a much larger patient cohort. CONCLUSIONS: Our data show that asporin is a stroma-derived inhibitor of TGF-beta1 and a tumor suppressor in breast cancer. High asporin expression is significantly associated with less aggressive tumors, stratifying patients according to the clinical outcome. Future pre-clinical studies should consider options for increasing asporin expression in TNBC as a promising strategy for targeted therapy. [less ▲]

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See detailTGF-B induced protein IG-H3 is essential for the growth of human liver metastases
Castronovo, Vincenzo ULg; Blomme, Arnaud; Delvenne, Philippe ULg et al

in Acta Gastro-Enterologica Belgica (2014, March), 77(1), 05

Introduction : Transforming growth factor-beta-induced protein ig-h3 (TGFBI) is extracellular matrix component known to be important for cell-collagen interaction. We and others have reported elevated ... [more ▼]

Introduction : Transforming growth factor-beta-induced protein ig-h3 (TGFBI) is extracellular matrix component known to be important for cell-collagen interaction. We and others have reported elevated expression of TGFBI in sev- eral human cancers, where its role remains controversial. Aim Current study aims at clarifying the function of TGFBI to date. Methods &Results : CRC-LM and in liver metastases originating from breast, lung and pancreatic tumors. We have next focused on func- tional aspects and have silenced TGFBI expression in SW1222 human colorectal carcinoma cells. The suppression of TGFBI protein led to a marked decrease in cell migration (-70%) and proliferation (-30%) in vitro. To study the effects in vivo we have developed a novel animal model of colorectal carcinoma based on chicken chorioallantoic membrane (CAM) that mimics human CRC-LM. TGFBI silencing resulted in 50% reduction of tumor volume in the CAM tumor model. Notably, the tumors displayed a marked inhibition of vascularization, suggesting an additional anti-angiogenic effect. Indeed, SW1222 cells silenced for TGFBI expression secreted lower levels of VEGFA in vitro. Finally, we have investigated if TGFBI can be used as systemically reachable target for antibody-drug delivery. For this purpose we have The in vivo data demonstrated that TGFBI is an accessible tumor target. Conclusions : Taken together, the present study shows that TGFBI is essential for promoting the development of CRC- LM and therefore represents a promising target for designing novel therapeutic approaches. [less ▲]

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See detailOrganized Proteomic Heterogeneity in Colorectal Cancer Liver Metastases and Implications for Therapies
Turtoi, Andrei ULg; Blomme, Arnaud; Debois, Delphine et al

in Hepatology (Baltimore, Md.) (2013)

Tumor heterogeneity is a major obstacle for developing effective anticancer treatments. Recent studies have pointed to large stochastic genetic heterogeneity within cancer lesions, where no pattern seems ... [more ▼]

Tumor heterogeneity is a major obstacle for developing effective anticancer treatments. Recent studies have pointed to large stochastic genetic heterogeneity within cancer lesions, where no pattern seems to exist that would enable a more structured targeted therapy approach. Because to date no similar information is available at the protein (phenotype) level, we employed matrix assisted laser desorption ionization (MALDI) image-guided proteomics and explored the heterogeneity of extracellular and membrane subproteome in a unique collection of eight fresh human colorectal carcinoma (CRC) liver metastases. Monitoring the spatial distribution of over 1,000 proteins, we found unexpectedly that all liver metastasis lesions displayed a reproducible, zonally delineated pattern of functional and therapeutic biomarker heterogeneity. The peritumoral region featured elevated lipid metabolism and protein synthesis, the rim of the metastasis dis- played increased cellular growth, movement, and drug metabolism, whereas the center of the lesion was characterized by elevated carbohydrate metabolism and DNA-repair activity. From the aspect of therapeutic targeting, zonal expression of known and novel biomarkers was evident, reinforcing the need to select several targets in order to achieve optimal coverage of the lesion. Finally, we highlight two novel antigens, LTBP2 and TGFBI, whose expression is a consistent feature of CRC liver metastasis. We demon- strate their in vivo antibody-based targeting and highlight their potential usefulness for clinical applications. Conclusion: The proteome heterogeneity of human CRC liver metastases has a distinct, organized pattern. This particular hallmark can now be used as part of the strategy for developing rational therapies based on multiple sets of target- able antigens. [less ▲]

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See detailImaging Guided Proteomics Unveils Heterogeniety in Colorectal Carcinoma Liver Metastases – Implications for Targeted Therapies.
blomme, Arnaud; Turtoi, Andrei ULg; Delvaux, David ULg et al

in Proceedings Giga Day 2012 (2012, May 04)

Detailed reference viewed: 47 (22 ULg)