ABSTRACT
To investigate the effects of gastrodin (GAS) on methamphetamine (MA)-induced conditioned place preference (CPP) in rats and explore its potential mechanisms. MA (10 mg/kg) was initially injected intraperitoneally (i.p.) in rats, after which they were administered either MA or saline alternately from day 4 to 13 (D4-13) for 10 days, followed by treatment with GAS (10 or 20 mg/kg, i.p.) on D15-21 for 7 days. The rats underwent CPP testing after MA and GAS treatment. In vitro, SH-SY5Y cells were exposed to MA (2.0 mM) for 24 h, followed by treatment with GAS (2.0 or 4.0 mM) for 24 h. The expression levels of PKA, P-PKA, CREB, and P-CREB proteins in the prefrontal cortex, nucleus accumbens, and ventral tegmental area of MA-induced CPP rats and in SH-SY5Y cells were detected by Western blot analysis. The MA-induced CPP rat model was successfully established. The administration of MA stimulated a significant alteration in behavior, as measured by the CPP protocol. After treatment with GAS, the amount of time rats spent in the MA-paired chamber was significantly reduced. Results also showed that MA increased the expression levels of PKA, P-PKA, CREB, and p-CREB proteins in the prefrontal cortex, nucleus accumbens, and ventral tegmental area of CPP rats and in SH-SY5Y cells (p < 0.05). GAS attenuated the effect of MA-induced CPP in rats and decreased the expression levels of proteins in vivo and in vitro. Our study suggests that GAS can attenuate the effects of MA-induced CPP in rats by regulating the PKA/CREB signaling pathway.
Subject(s)
Benzyl Alcohols/pharmacology , Central Nervous System Stimulants/toxicity , Conditioning, Psychological/physiology , Cyclic AMP Response Element-Binding Protein/metabolism , Cyclic AMP-Dependent Protein Kinases/metabolism , Glucosides/pharmacology , Methamphetamine/toxicity , Animals , Cell Line, Tumor , Conditioning, Psychological/drug effects , Humans , Male , Prefrontal Cortex/drug effects , Prefrontal Cortex/metabolism , Random Allocation , Rats , Rats, Sprague-DawleyABSTRACT
Directional migration is a cost-effective movement allowing invasion and metastatic spread of cancer cells. Although migration related to cytoskeletal assembly and microenvironmental chemotaxis has been elucidated, little is known about interaction between extracellular and intracellular molecules for controlling the migrational directionality. A polarized expression of prohibitin (PHB) in the front ends of CRC cells favors metastasis and is correlated with poor prognosis for 545 CRC patients. A high level of vascular endothelial growth factor (VEGF) in the interstitial tissue of CRC patients is associated with metastasis. VEGF bound to its receptor, neuropilin-1, can stimulate the activation of cell division cycle 42, which recruits intra-mitochondrial PHB to the front end of a CRC cell. This intracellular relocation of PHB results in the polymerization and reorganization of filament actin extending to the front end of the cell. As a result, the migration directionality of CRC cells is targeted towards VEGF. Together, these findings identify PHB as a key modulator of directional migration of CRC cells and a target for metastasis.
ABSTRACT
Growth and invasion of metastatic colorectal cancer (CRC) cells in the liver depend on microenvironment. Here, we showed that human hepatic sinusoidal endothelial cells (HHSECs) induce chemotaxis and outgrowth of CRC cells. Macrophage migration inhibitory factor (MIF), released by HHSECs, stimulated chemotaxis of CRC cells. MIF secreted by HHSECs, but not by CRC cells themselves, promoted migration and epithelial-mesenchymal transition (EMT) and facilitated proliferation and apoptotic resistance of CRC cells. In orthotopic implantation models in nude mice, exogenous MIF stimulated growth of CRC cells and metastasis. Furthermore, MIF accelerated mobility of CRC cells by suppressing F-actin depolymerization and phosphorylating cofilin. Noteworthy, MIF levels were correlated with the size of hepatic metastases. We suggest that HHSECs and paracrine MIF promote initial migration and proliferation of CRC cells in the hepatic sinusoids to generate liver metastases.
