Abstract 3774: Regulation of the pro-invasive properties of neuroblastoma-stem cells by membrane type-1 matrix metalloproteinase

Neuroblastoma (NB) is an aggressive childhood cancer that represents the leading cause of cancer deaths in children. Despite aggressive therapy, more than half of the children with advanced NB usually die because of uncontrolled metastatic disease. In order to develop new therapeutic strategies to limit NB's metastatic potential, it is crucial to identify key molecular targets governing the invasive process. The study of Cancer stem cells (CSCs) may be of interest in this regard because after chemotherapy, CSCs persist in tumors and cause relapse and metastasis. We had recently demonstrated that CD133 allowed to detect CSCs in NB. Membrane type-1 matrix metalloproteinase (MT1-MMP) is important in the metastatic process and its expression was correlated with unfavourable outcome in NBs. Our preliminary data had indicated that MT1-MMP was highly expressed in CD133high NB.

The purpose of this study is to characterize the interaction between CD133 and MT1-MMP in NB and determinate the role of MT1-MMP in pro-invasive properties of CSCs. We constructed paraffin-embedded blocks of tissue microarrays (TMA) from 235 patients. In vitro experiments were performed on four established NB cell lines (SK-N-DZ, SK-N-FI and SK-N-SH and SJNB-10). We performed immunohistochemical studies on paraffin-embedded TMA sections with two antibodies (CD133, MT1-MMP). To verify correlation of expression of MT1-MMP and CD133, we realized western blot and immunofluorescence (IF) of both proteins in non treated versus treated NB cell lines. CD133high NB cells were isolated by flow cytometry. CD133high and CD133low NB cells were grown within a 3D collagen matrix and the cell migration assay was tested in collagen-coated transwells. All experiments were performed with or without an anti-MT1-MMP neutralizing antibody or GM6001, a broad-spectrum MMP inhibitor.

To assess the interaction between CD133 and MT1-MMP, lysates were subjected to immunoprecipitation (IP) using an anti-CD133 antibody, followed by immunodetection with an anti-MT1-MMP antibody. Finally, we determined which domain of MT1-MMP is involved in its interaction with CD133. Different dominant negative mutants of MT1-MMP (catalytically inactive E240A, cytoplasmic domain-deleted CΔ20 and non-phosphorylatable Y573F) were transfected into NB cells followed by an IP.

There is a correlation between MT1-MMP and CD133 expressions in tumors of patients and in cell lines. Cells selected after chemotherapy express both CD133 and MT1-MMP. CD133high cells presented higher migration and invasion properties than CD133low which were MT1-MMP dependent. IF and IP showed a colocalization and interaction between CD133 and MT1-MMP. The cytoplasmic domain of MT1-MMP seems to be responsible for the interaction with CD133.

These results contribute to a better understanding CSCs properties in NB and may be of great interest to improve new therapeutic strategies.

Citation Format: Assila Belounis, Carine Nyalendo, Sonia Cournoyer, Sarah Hadj-Mimoune, Alexandre Benoit, Elliot Lasalle, Jonathan Girard, Mona Beaunoyer, Pierre Teira, Hervé Sartelet. Regulation of the pro-invasive properties of neuroblastoma-stem cells by membrane type-1 matrix metalloproteinase. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 3774. doi:10.1158/1538-7445.AM2013-3774

Delta-9-tetrahydrocannabinol during pregnancy in the rat: I. Differential effects on maternal nutrition, embryotoxicity, and growth in the offspring

Either 15 or 50 mg/kg of delta-9-tetrahydrocannabinol (THC) in sesame oil was administered by gastric intubation to gravid rats during the last two weeks of gestation. A pair-fed control group was administered the vehicle alone and allowed to eat and drink only the amount consumed by the 50 mg/kg group on the same gestation days. A nontreated control group was left undisturbed during pregnancy. All treated and control litters were fostered at birth to untreated dams. Among the dams receiving 50 mg/kg of THC, food and water intake was initially reduced to 75-80% of nontreated controls but then recovered over 3-4 days to approximately a 15-20% reduction until term. Compared with the nontreated dams, both THC dose-level groups and pair-fed control dams gained significantly less body weight from conception to term. Offspring mortality did not differ between the nontreated and pair-fed controls but was significantly higher among both dose-level THC exposed groups. In addition, there was a dose-related increase in the sex-ratio of live male to female offspring as well as significant effects on rate of growth for both sexes. The results are discussed with respect to published animal and clinical studies of cannabinoid exposure during pregnancy.

Delta-9-tetrahydrocannabinol during pregnancy in the rat: II. Effects on ontogeny of locomotor activity and nipple attachment in the offspring

Either 15 or 50 mg/kg delta-9-tetrahydrocannabinol (THC) in sesame oil was administered by gastric intubation to gravid rats during the last two weeks of gestation. A pair-fed control group was administered the vehicle alone and allowed to eat and drink only the amount consumed by the 50 mg/kg group on the same gestation days. A nontreated control group was left undisturbed during pregnancy. All treated and control litters were fostered at birth to untreated dams. Intact litters from the two THC treated and the two control groups were tested at 3-day intervals from birth to 32 days of age for differences in locomotor activity. In addition, pups were tested for nipple attachment on days 2, 5, 8, 11, and 14 of age. There were no differences in locomotor activity among any of the groups although activity level varied during development. Pups from dams exposed to 50 mg/kg of THC, as well as the pair-fed controls, displayed significantly longer latencies to attach to a nipple. These results suggest that the impaired nipple attachment observed among the high-dose offspring was not a primary effect of THC, but rather was secondary to the significant reduction of food and water intake among the dams. The behavioral findings are discussed with respect to other animal and clinical reports of prenatal cannabinoid exposure.