RESUMO
ß-catenin signaling, and angiogenesis are associated with colospheroid (CSC), development. CSCs, spheroids derived from colon cancer cells, are responsible for metastasis, drug resistance, and disease recurrence. Whether dysregulating ß-catenin and inhibiting angiogenesis reduce CSC growth is unknown. In this study, the molecular mechanism of CSC growth inhibition was evaluated using a novel combination of melatonin (MLT) and andrographolide (AGP). These drugs have anticarcinogenic, antioxidant, and antimetastatic properties. CSCs were obtained from two metastatic colon cancer cell lines (HT29 and HCT-15). The viability and stemness were monitored (FDA propidium iodide staining and immunoblot for CD44, CD133, Nanog, Sox2, and Oct4). The drug combination synergistically diminished stemness via increased reactive oxygen species (ROS) levels, reduced mitochondrial membrane potential and ATP level. MLT + AGP induced cell death by inhibiting ß-catenin expression and its downregulatory signals, Cyclin D1, c-Myc. MLT + AGP treated cells exhibited translocation of phospho-ß-catenin to the nucleus and dephosphorylated-ß-catenin. Downregulation of ß-catenin activation and its transcription factors (TCF4 and LEF1) and GTP binding/G-protein related activity were found in the dual therapy. Angiogenic inhibition is consistent with downregulation of VEGF messenger RNA transcripts (VEGF189), phosphorylated VEGF receptor protein expression, matrigel invasion, and capillary tube inhibition. In vivo, the intravenous injection of MLT + AGP slowed HT29 metastatic colon cancer. Histopathology indicated significant reduction in microvascular density and tumor index. Immunohistochemistry for caspase 7, and ß-catenin found increased apoptosis and downregulation of ß-catenin signals. The mechanism(s) of decreased colospheroids growth were the inhibition of the Wnt/ß-catenin pathway. Our results provide a rationale for using MLT in combination with AGP for the inhibition of CRCs.
Assuntos
Neoplasias do Colo , Melatonina , Linhagem Celular Tumoral , Proliferação de Células , Neoplasias do Colo/metabolismo , Diterpenos , Humanos , Melatonina/metabolismo , Melatonina/farmacologia , Células-Tronco Neoplásicas/metabolismo , Fenótipo , Via de Sinalização Wnt/genética , beta Catenina/genéticaRESUMO
Choline is an essential nutrient with many roles in brain development and function. Supplementation of choline in early development can have long-lasting benefits. Our experiments aimed to determine the efficacy of choline supplementation in a postnatal day (PND) 10 rat model of neonatal hypoxia ischemia (HI) at term using both male and female rat pups. Choline (100 mg/kg) or saline administration was initiated the day after birth and given daily for 10 or 14 consecutive days. We determined choline's effects on neurite outgrowth of sex-specific cultured cerebellar granule cells after HI with and without choline. The magnitude of tissue loss in the cerebrum was determined at 72 h after HI and in adult rats. The efficacy of choline supplementation in improving motor ability and learning, tested using eyeblink conditioning, were assessed in young adult male and female rats. Overall, we find that choline improves neurite outgrowth, short-term histological measures and learning ability in males. Surprisingly, choline did not benefit females, and appears to exacerbate HI-induced changes.