T form tumors and spontaneously metastasize following injection. Female BALB/c mice (4-weeks old; Harlan, Gannat, France) were intramuscularly injected with 106 cells/20 ml of PBS in thigh muscles (one per leg; 9 mice per group). After 6 weeks, mice were euthanized, all tumors were dissected, and tumor size was determined using a calliper. Primary tumors and lungs were fixed in formalin and included in paraffin. Tissue sections (5 mm) were stained with hematoxylin/eosin or SC 1 immunostained with anti-Ki67 antibody (1/100; Abcam). All fields located outside of the necrotic center and without the remaining muscular fibers were microphotographed under an Olympus microscope. TUNEL assay was performed using the ApoptagH Peroxidase In Situ Apoptosis Detection Kit (Millipore, Billerica, MA, USA) according to the manufacturer’s recommendations.Statistical Analysis Immunoblot AnalysisCell lysates were prepared and resolved on 10 SDS-PAGE as previously described [19] were incubated with (-)-Indolactam V rabbit anti-FHL2 (1/1000; Abcam, Cambridge, UK), mouse anti-b-catenin (1/1000; Santa Cruz, Santa Cruz Biotechnology, CA, USA), rabbit anti-bThe in vitro data are the mean 6 s.d. and are representative of at least three experiments. The in vivo data are the mean 6 s.d. The data were analyzed by Student’s t-test with P,0.05 considered to be significant. The TMA scoring was expressed as the mean 6 s.e.m. and was analysed by Kruskal-Wallis test followed by Tukey test.FHL2 Silencing Reduces Osteosarcoma TumorigenesisAuthor ContributionsConceived and designed the experiments: JB FXD OF PJM. Performed the experiments: JB CM. Analyzed the data: JB OF PJM. Contributedreagents/materials/analysis tools: JM RS APG FL. Wrote the paper: JB OF PJM.
Cartilage Link Protein 1 (Crtl1; also known as Hyaluronan and Proteoglycan Binding Protein 1- Hapln1) is a glycoprotein found in the extracellular matrix (ECM) of multiple tissues, including cartilage, brain and heart [1?]. Crtl1 is involved in the formation and stabilization of proteoglycan and hyaluronan aggregates [4,5] and is important for preventing aggregate degradation by proteases such as members of the ADAMTS and MMP families [5?]. Loss of Crtl1 results in impairment of growth and development of several tissues, including the cartilage, heart, and central nervous system [1?]. Crtl1 null mice are characterized by craniofacial abnormalities and shortened long bones, abnormalities attributed to a reduction in aggrecan within the cartilage resulting in an inability of chondrocytes to differentiate and hypertrophy [3]. Cardiac malformations seen in Crtl1 knockout mice include muscular ventricular septal defects, atrioventricular septal defects, and thin myocardium [2]. Crtl1 knockout mice die perinatally which has been attributed to compromised lung development [3]. The mechanisms governing regulation of ECM protein expression are complex and involve many signaling pathways[8]. Recent studies have shown that similarities exist between the transcriptional programs that regulate bone formation and the formation of cardiac valves during development (reviewed in [9]). In the developing bone and the AV valves, Crtl1 has previously been shown to be directly regulated by the transcription factor, Sox9 [10,11]. Conditionally deleting Sox9 in the valves of the developing mouse heart does, however, not completely abolish Crtl1 expression, indicating that the expression of Crtl1 in the developing valves is not solely dependent on Sox9 [12]. Duri.T form tumors and spontaneously metastasize following injection. Female BALB/c mice (4-weeks old; Harlan, Gannat, France) were intramuscularly injected with 106 cells/20 ml of PBS in thigh muscles (one per leg; 9 mice per group). After 6 weeks, mice were euthanized, all tumors were dissected, and tumor size was determined using a calliper. Primary tumors and lungs were fixed in formalin and included in paraffin. Tissue sections (5 mm) were stained with hematoxylin/eosin or immunostained with anti-Ki67 antibody (1/100; Abcam). All fields located outside of the necrotic center and without the remaining muscular fibers were microphotographed under an Olympus microscope. TUNEL assay was performed using the ApoptagH Peroxidase In Situ Apoptosis Detection Kit (Millipore, Billerica, MA, USA) according to the manufacturer’s recommendations.Statistical Analysis Immunoblot AnalysisCell lysates were prepared and resolved on 10 SDS-PAGE as previously described [19] were incubated with rabbit anti-FHL2 (1/1000; Abcam, Cambridge, UK), mouse anti-b-catenin (1/1000; Santa Cruz, Santa Cruz Biotechnology, CA, USA), rabbit anti-bThe in vitro data are the mean 6 s.d. and are representative of at least three experiments. The in vivo data are the mean 6 s.d. The data were analyzed by Student’s t-test with P,0.05 considered to be significant. The TMA scoring was expressed as the mean 6 s.e.m. and was analysed by Kruskal-Wallis test followed by Tukey test.FHL2 Silencing Reduces Osteosarcoma TumorigenesisAuthor ContributionsConceived and designed the experiments: JB FXD OF PJM. Performed the experiments: JB CM. Analyzed the data: JB OF PJM. Contributedreagents/materials/analysis tools: JM RS APG FL. Wrote the paper: JB OF PJM.
Cartilage Link Protein 1 (Crtl1; also known as Hyaluronan and Proteoglycan Binding Protein 1- Hapln1) is a glycoprotein found in the extracellular matrix (ECM) of multiple tissues, including cartilage, brain and heart [1?]. Crtl1 is involved in the formation and stabilization of proteoglycan and hyaluronan aggregates [4,5] and is important for preventing aggregate degradation by proteases such as members of the ADAMTS and MMP families [5?]. Loss of Crtl1 results in impairment of growth and development of several tissues, including the cartilage, heart, and central nervous system [1?]. Crtl1 null mice are characterized by craniofacial abnormalities and shortened long bones, abnormalities attributed to a reduction in aggrecan within the cartilage resulting in an inability of chondrocytes to differentiate and hypertrophy [3]. Cardiac malformations seen in Crtl1 knockout mice include muscular ventricular septal defects, atrioventricular septal defects, and thin myocardium [2]. Crtl1 knockout mice die perinatally which has been attributed to compromised lung development [3]. The mechanisms governing regulation of ECM protein expression are complex and involve many signaling pathways[8]. Recent studies have shown that similarities exist between the transcriptional programs that regulate bone formation and the formation of cardiac valves during development (reviewed in [9]). In the developing bone and the AV valves, Crtl1 has previously been shown to be directly regulated by the transcription factor, Sox9 [10,11]. Conditionally deleting Sox9 in the valves of the developing mouse heart does, however, not completely abolish Crtl1 expression, indicating that the expression of Crtl1 in the developing valves is not solely dependent on Sox9 [12]. Duri.