A V530I Mutation in c-KIT Exon 10 Is Associated to Imatinib Response in Extraabdominal Aggressive Fibromatosis

Aggressive fibromatosis (AF) or desmoid tumor is a rare condition, characterized by deep tissue invasion by a monoclonal fibroblastic neoplasm, developed from musculoaponeurotic structures. Surgery is the treatment of choice, but negative margins can hardly been achieved in large tumors, and can lead to major functional disability. AF medical therapy includes nonsteroids anti-inflammatory drugs, tamoxifen, with inconsistent results. Several reports of imatinib efficacy in AF appear in the literature. Here, we describe for the first time a V530I KIT exon 10 mutant that was associated to a dramatic imatinib response in an extraabdominal aggressive fibromatosis. The previously discovered V530I substitution was characterized in the core binding factor AML, but had never been reported in any other condition, so far. In this paper, we discuss the KIT exon 10 mutations or polymorphisms that have been described in a variety of KIT-related conditions, including acute myelogenous leukemia, mastocytosis, and aggressive fibromatosis

Les fibromatoses agressives ou tumeurs desmoïdes (recherche de facteurs cliniques, histologiques et moléculaires liés à la rechute et à la sensibilité thérapeutique. A propos d'une série de 77 cas.)

STRASBOURG-Medecine (674822101) / SudocSudocFranceF

Constitutively Active Androgen Receptor Variants Upregulate Expression of Mesenchymal Markers in Prostate Cancer Cells

<div><p>Androgen receptor (AR) signaling pathway remains the foremost target of novel therapeutics for castration-resistant prostate cancer (CRPC). However, the expression of constitutively active AR variants lacking the carboxy-terminal region in CRPC may lead to therapy inefficacy. These AR variants are supposed to support PCa cell growth in an androgen-depleted environment, but their mode of action still remains unresolved. Moreover, recent studies indicate that constitutively active AR variants are expressed in primary prostate tumors and may contribute to tumor progression. The aim of this study was to investigate the impact of constitutively active AR variants on the expression of tumor progression markers. N-cadherin expression was analyzed in LNCaP cells overexpressing the wild type AR or a constitutively active AR variant by qRT-PCR, Western blot and immunofluorescence. We showed here for the first time that N-cadherin expression was increased in the presence of constitutively active AR variants. These results were confirmed in C4-2B cells overexpressing these AR variants. Although N-cadherin expression is often associated with a downregulation of E-cadherin, this phenomenon was not observed in our model. Nevertheless, in addition to the increased expression of N-cadherin, an upregulation of other mesenchymal markers expression such as <i>VIMENTIN, SNAIL</i> and <i>ZEB1</i> was observed in the presence of constitutively active variants. In conclusion, our findings highlight novel consequences of constitutively active AR variants on the regulation of mesenchymal markers in prostate cancer.</p></div

N-cadherin expression is upregulated in the presence of constitutively active androgen receptor variants.

<p>A). N-cadherin expression was assessed by qRT-PCR in LNCaP cells overexpressing the constitutively active AR Q640X or AR-V7, or the AR-WT and in cells transfected with the empty plasmid (C3). Cells were grown in complete medium for 9 days after transfection. Parental LNCaP cells were used as control. y-Axis represents the relative fold change compared with control (parental LNCaP cells). <i>β-ACTIN</i> was used as the endogenous normalization control. Relative expression is presented as the mean ± SEM from three independent experiments. Each sample is compared one by one by two tail unpaired t test. <i>NS: Not significant * P<0.05, **P<0.01 and ***P<0.001</i>. B). Western Blot showing AR expression in transfected and non transfected LNCaP cells. C). Immunoblot analysis of N-cadherin expression in transfected LNCaP cells 4 and 9 days after transfection. D). Kinetic analysis of N-cadherin expression by Western Blot in LNCaP cells overexpressing AR Q640X from 2 to 9 days after transfection. β-actin was used as loading control.</p

List of primers used in qRT-PCR experiments.

<p>List of primers used in qRT-PCR experiments.</p

N-cadherin upregulation was restricted to LNCaP cells expressing constitutively active androgen receptor variants.

<p>LNCaP cells were transiently transfected with pEGFP-ARWT or pEGFP-ARQ640X plasmid and were sorted 4 days after. A). <i>N-CADHERIN</i> expression was analyzed by qRT-PCR in EGFP positive (transfected) and EGFP negative (non-transfected) fractions. B). Androgen receptor (AR) level was analyzed by Western Blot to verify the purity of each fraction after cell sorting. C). Immunofluorescence analysis of N-cadherin (red fluorescence) expression in LNCaP cells transfected with EGFP-tagged (green fluorescence) AR-WT, AR Q640X or AR Q670X expression plasmid. Magnification: ×20.</p

Androgens abrogate N-cadherin upregulation induced by constitutively active androgen receptor variants in LNCaP cells.

<p>A). LNCaP cells were grown in RPMI-1640 containing 5% DCC-FCS and 100 nM of DHT or vehicle (EtOH). N-cadherin expression was analyzed by qRT-PCR in LNCaP cells 4 days after transfection with AR-WT or the constitutively active AR Q640X or AR-V7 expression plasmid. B). N-cadherin expression level in LNCaP cells was investigated by qRT-PCR 4 days after transfection with AR Q640X expression plasmid in the presence of different DHT concentrations (10 nM, 25 nM and 50 nM) or vehicle. C). N-cadherin expression induced by constitutively active AR variants (AR variants) was negatively regulated when LNCaP cells were grown in the presence of DHT. We hypothesize that endogenous AR-FL present in LNCaP cells and AR variants could act differently. In this model, DHT-stimulated endogenous AR-FL represses N-cadherin expression whereas AR variants upregulate its expression. D). LNCaP cells overexpressing AR-WT, AR Q640X and AR-V7 were cultured in DCC-FCS medium supplemented with 100 nM of DHT and in the presence of 100 nM of MDV3100 or DMSO as control during 3 days. N-cadherin expression was analyzed by qRT-PCR 4 days after transfection, and was normalized to <i>β-ACTIN</i>. The ΔΔCt method was used to calculate relative expression and each value was reported as the mean of ΔΔCt ± SEM. <i>NS: Not Significant * P<0.05, **P<0.01 and ***P<0.001</i>.</p

Insulin-like growth factor type 1 receptor (IGF-1R) exclusive nuclear staining: a predictive biomarker for IGF-1R monoclonal antibody (Ab) therapy in sarcomas.

International audienceAIMS: A minority of patients with advanced sarcoma achieve prolonged progression free survival (PFS) with insulin growth factor type 1 receptor (IGF-1R) monoclonal antibody (Ab) therapy. A biomarker identifying those patients beforehand would be useful to select patients for the development of these agents. METHODS: This single centre series includes patients with unresectable or metastatic soft tissue sarcomas (STS), Ewing sarcoma (ES) and osteosarcoma treated with IGF-1R Ab (R1507, IMC-A12, SCH 717454 and CP-751.871) in the Centre Léon Bérard. Tumour samples were analysed by immunohistochemistry for expression of IGF-1R, insulin-like growth factor binding protein type 3 (IGFBP-3), Ki67, epidermal growth factor receptor (HER1) and human epidermal growth factor receptor 2 (HER2). Predictive factors for PFS and overall survival (OS) were investigated. RESULTS: All tumour samples had a positive IGF-1R immunostaining on 60% to 100% of tumour cells. IGFBP-3 immunostaining was observed in 12 (75%) samples with 5% to 100% of positive cells. IGF-1R immunostaining was nuclear (n=9, 56%), cytoplasmic (n=4, 25%), or nuclear +cytoplasmic (n=3, 19%). Neither IGFBP-3 expression, nor Ki67 was correlated to PFS. HER2 and HER1 staining were positive in 0 and 2 samples respectively (both primary resistant to IGF-1R Ab therapy). Exclusive intra-nuclear immunoreactivity for IGF-1R was significantly associated with a better PFS (p=0.01) and OS (p=0.007). CONCLUSION: Exclusive nuclear localisation of IGF-1R is an easily testable biomarker associated with a better PFS and OS for patients treated with IGF-1R Ab therapy. Nuclear localisation of IGF-1R in tumour cells might be a hallmark of pathway activation

Bevacizumab plus microtubule targeting agents in heavily pre-treated ovarian cancer patients: a retrospective study.

International audienceOBJECTIVES. As vascular endothelial growth factor (VEGF) is expressed in ovarian cancer, we assessed the efficacy and safety of bevacizumab (a monoclonal antibody targeting VEGF) plus microtubule targeting agents for heavily pre-treated ovarian carcinoma patients. METHODS. We retrospectively reviewed 43 patients with recurrent epithelial ovarian carcinoma. Combined treatment included bevacizumab with paclitaxel in 32 (74%), docetaxel in 10 (23%), and vinorelbine in one (2.3%) patients, respectively. RESULTS. The median number of combined treatment was six cycles (range 1-29). On RECIST criteria, the objective response rate (ORR) was 40% (16% CR and 24% PR). Clinical benefit (complete response [CR] plus partial response [PR] and stable disease [SD] lasting ≥ 3 months) was 74% (CI95%: 46.7-77%). Median duration of treatment and overall survival were 3.9 months (range 0.2-14.4 months) and 20.1 months (CI95%: 13.8-20.1) respectively. No toxic death was reported. Grade 3-4 toxicity occurred in 30% of patients. Gastrointestinal perforations and fistula occurred in 3 (7%) and 6 (14%) patients, respectively. CONCLUSION. Although being active in terms of ORR, bevacizumab plus microtubule targeting agents - mainly taxanes - leads to a high rate of gastro-intestinal perforations and fistula in heavily pre-treated ovarian carcinoma patients

Safety of bevacizumab in clinical practice for recurrent ovarian cancer: A retrospective cohort study

International audienceThe poor outcome of patients with recurrent ovarian cancer constitutes a continuous challenge for decision-making in clinical practice. In this setting, molecular targets have recently been identified, and novel compounds are now available. Bevacizumab has been introduced for the treatment of patients with ovarian cancer and is, to date, the most extensively investigated targeted therapy in this setting. However, potential toxicities are associated with the use of this monoclonal antibody. These toxicities have been reported in clinical trials, and can also be observed outside of trials. As limited data is currently available regarding the safety of bevacizumab treatment in daily clinical practice, the current retrospective study was designed to evaluate this. Data from 156 patients with recurrent ovarian cancer who had received bevacizumab treatment between January 2006 and June 2009 were retrospectively identified from the institutional records of five French centers. In contrast to clinical trials, the patients in the present study were not selected and had a heterogeneous profile according to their prior medical history, lines of treatment prior to bevacizumab introduction and number of relapses. The results first confirm the effect of heavy pretreatment on the occurrence of serious and fatal adverse events in clinical practice, as previously reported for clinical trials and for other retrospective cohort studies. Importantly, the data also demonstrates, for the first time, that medical history of hypertension is an independent predictive risk factor for the development of high-grade hypertension during bevacizumab treatment. These results thus suggest that treating physicians must consider all risk factors for managing bevacizumab toxicity prior to its introduction. Such risk factors include the time of bevacizumab introduction, a patient's history of hypertension and a low incidence of pre-existing obstructive diseas