ABSTRACT
Recent studies have indicated that ATRA inhibits chondrogenesis and can lead to congenital clubfoot (CCF). The molecular mechanism of ATRA-induced chondrogenesis is not clear. As RhoA/ROCK and SDF-1/CXCR4 signaling play important molecular roles for a variety of cellular processes, we hypothesized that RhoA/ROCK2 and SDF-1/CXCR4 signaling are involved in ATRA-induced chondrogenesis in rat embryo hind limb bud mesenchymal cells (rEHBMCs). We found that ATRA dose-dependently inhibits proliferation and expression of chondrogenic transcription factors (SOX9 and COL2A1) in rEHBMCs. In contrast, ATRA increases the expression of ROCK2, SDF-1 and CXCR4. Pharmacological inhibition of ROCK signaling and SDF-1/CXCR4 signaling by Y27632 and AMD3100, respectively, resulted in elevated expression of SOX9 and COL2A1. In addition, we found that disturbing SDF-1/CXCR4 signaling by AMD3100 decreases ATRA-induced ROCK2 expression. In vivo studies we also confirm that SOX9 expression of early-stage cartilage progenitors in the proliferative zone and COL2A1 expression in prehypertrophic chondrocytes are decreased in ATRA-treated rat embryo hind limb. Together, these results show that ATRA activates SDF-1/CXCR4/ROCK2 signaling to inhibit chondrogenesis to lead to CCF by suppressing differentiation through down-regulation of SOX9 and COL2A1 expression in rat embryo hind limb bud mesenchymal cells.
ABSTRACT
Naringin is an active compound extracted from Rhizoma Drynariae, and studies have revealed that naringin can promote proliferation and osteogenic differentiation of bone marrow stromal cells (BMSCs). In this study, we explored whether naringin could promote osteogenic differentiation of BMSCs by upregulating Foxc2 expression via the Indian hedgehog (IHH) signaling pathway. BMSCs were cultured in basal medium, basal medium with naringin, osteogenic induction medium, osteogenic induction medium with naringin and osteogenic induction medium with naringin in the presence of the IHH inhibitor cyclopamine (CPE). We examined cell proliferation by using a WST-8 assay, and differentiation by Alizarin Red S staining (for mineralization) and alkaline phosphatase (ALP) activity. In addition, we detected core-binding factor α1 (Cbfα1), osteocalcin (OCN), bone sialoprotein (BSP), peroxisome proliferation-activated receptor gamma 2 (PPARγ2) and Foxc2 expression by using RT-PCR. We also determined Foxc2 and IHH protein levels by western blotting. Naringin increased the mineralization of BMSCs, as shown by Alizarin red S assays, and induced ALP activity. In addition, naringin significantly increased the mRNA levels of Foxc2, Cbfα1, OCN, and BSP, while decreasing PPARγ2 mRNA levels. Furthermore, the IHH inhibitor CPE inhibited the osteogenesis-potentiating effects of naringin. Naringin increased Foxc2 and stimulated the activation of IHH, as evidenced by increased expression of proteins that were inhibited by CPE. Our findings indicate that naringin promotes osteogenic differentiation of BMSCs by up-regulating Foxc2 expression via the IHH signaling pathway.
ABSTRACT
Naringin is a major flavonoid found in grapefruit and is an active compound extracted from the Chinese herbal medicine Rhizoma Drynariae. Naringin is a potent stimulator of osteogenic differentiation and has potential application in preventing bone loss. However, the signaling pathway underlying its osteogenic effect remains unclear. We hypothesized that the osteogenic activity of naringin involves the Notch signaling pathway. Rat bone marrow stromal cells (BMSCs) were cultured in osteogenic medium containing-naringin, with or without DAPT (an inhibitor of Notch signaling), the effects on ALP activity, calcium deposits, osteogenic genes (ALP, BSP, and cbfa1), adipogenic maker gene PPARγ2 levels, and Notch expression were examined. We found that naringin dose-dependently increased ALP activity and Alizarin red S staining, and treatment at the optimal concentration (50 µg/mL) increased mRNA levels of osteogenic genes and Notch1 expression, while decreasing PPARγ2 mRNA levels. Furthermore, treatment with DAPT partly reversed effects of naringin on BMSCs, as judged by decreases in naringin-induced ALP activity, calcium deposits, and osteogenic genes expression, as well as upregulation of PPARγ2 mRNA levels. These results suggest that the osteogenic effect of naringin partly involves the Notch signaling pathway.
ABSTRACT
BACKGROUND: This study aimed to investigate the clinicopathological features and prognosis of operable breast cancers in young and elderly Chinese women. PATIENTS AND METHODS: This study included 209 patients aged ≤35 years and 213 patients aged ≥60 but <70 years, who received treatment between January 2000 and December 2004. The clinicopathological features, molecular subtypes, therapeutic strategies, and prognosis were evaluated. RESULTS: Tumor size was of significant difference between the 2 groups (p = 0.018), with more T2 and T3 tumors in the young group and more lymph node involvement in young patients with stage T1 tumors (p = 0.033). There were more triple-negative and less luminal A tumors in the young group (p = 0.018). 47.1% of tumors were not detected by mammography in the young group as compared to 5.5% in the elderly group (p < 0.001). More patients received chemotherapy in the young group (p < 0.001) and preferred breast-conserving surgery (p = 0.031). The 6-year disease-free survival (DFS) was 80 and 66% in the elderly and the young group, respectively (p = 0.001), but no difference was seen in overall survival. CONCLUSIONS: Compared with elderly women, young breast cancer patients have different clinicopathological features and molecular subtypes, and poorer DFS. Furthermore, the insidious onset of breast cancer in young women suggests that clinicians should pay more attention to young women with breast abnormalities.