Red ginseng polysaccharide exhibits anticancer activity through GPX4 downregulation-induced ferroptosis.

CONTEXT: Red ginseng polysaccharide (RGP) is an active component of the widely used medicinal plant Panax ginseng C. A. Meyer (Araliaceae), which has displayed promising activities against cancer cells. However, the detailed molecular mechanism of RGP in ferroptosis is still unknown. OBJECTIVE: This study evaluates the effects of RGP in cancer cells. MATERIALS AND METHODS: A549 and MDA-MB-231 cells were used. Cell proliferation was measured by CCK-8 assay after being treated with RGP at concentrations of 0, 50, 100, 200, 400, 800 and 1600 µg/mL at 0, 12, 24 and 48 h. Lipid reactive oxygen species (ROS) levels were assessed by C11-BODIPY assay. The control group was treated with PBS. RESULTS: RGP inhibited human A549 (IC50: 376.2 µg/mL) or MDA-MB-231(IC50: 311.3 µg/mL) proliferation and induced lactate dehydrogenase (LDH) release, promoted ferroptosis and suppressed the expression of GPX4. Moreover, the effects of RGP were enhanced by the ferroptosis inducer erastin, while abolished by ferroptosis inhibitor ferrostatin-1. DISCUSSION AND CONCLUSIONS: Our study is the first to demonstrate (1) the anticancer activity of RGP in human lung cancer and breast cancer. (2) RGP presented the anti-ferroptosis effects in lung and breast cancer cells via targeting GPX4.

Acupuncture reduces nicotine-induced norepinephrine release in the hypothalamus via the solitary NMDA receptor/NOS pathway.

Noradrenergic projections from the nucleus tractus solitarius (NTS) to the hypothalamic paraventricular nucleus (PVN) are involved in nicotine (Nic) dependence. Nic induces hypothalamic norepinephrine (NE) release through N-methyl-d-aspartate receptors (NMDARs) and nitric oxide in the NTS. However, acupuncture attenuates Nic withdrawal-induced anxiety. Therefore, this study investigated the effects of acupuncture on Nic-induced hypothalamic NE release. Rats received an intravenous infusion of Nic (90 µg/kg, over 60 s) and extracellular NE levels in the PVN were determined by in vivo microdialysis. Immediately after Nic administration, the rats were bilaterally treated with acupuncture at acupoint HT7 (Shen-Men) or PC6 (Nei-Guan), or a non-acupoint (tail) for 60 s. Acupuncture at HT7, but not at PC6 or the tail, significantly reduced Nic-induced NE release. However, this was abolished by a post-acupuncture infusion of either NMDA or sodium nitroprusside into the NTS. Additionally, acupuncture at HT7, but not the control points, prevented Nic-induced plasma corticosterone secretion and inhibited Nic-induced increases in the phosphorylation of neuronal nitric oxide synthase (nNOS) and endothelial NOS in the NTS. These findings suggest that acupuncture at HT7 reduces Nic-induced NE release in the PVN via inhibition of the solitary NMDAR/NOS pathway.

Blockade of nicotine sensitization by methanol extracts of Glycyrrhizae radix mediated via antagonism of accumbal oxidative stress.

BACKGROUND: We previously reported that a methanol extract of Glycyrrhizae radix (MEGR) blocked methamphetamine-induced locomotor sensitization and conditioned place preference in rats. In the present study, the effects of MEGR on repeated nicotine-induced locomotor sensitization and enhanced extracellular dopamine (DA) release in the nucleus accumbens (Nacc) were evaluated. METHODS: Male Sprague-Dawley rats received repeated administrations of nicotine (0.4 mg/kg, subcutaneous) or saline twice a day for 7 d and were challenged with nicotine 4 d after the last daily dosing. During the 4-d withdrawal period, the rats were treated once a day with MEGR (60 or 180 mg/kg/d). Extracellular DA levels were measured by in vivo microdialysis, the malondialdehyde levels and the activities of superoxide dismutase and catalase in the Nacc were biochemically evaluated, and the expression of antioxidant proteins was confirmed by Western blot assays. All data were assessed with analysis of variance tests followed by post-hoc comparison tests and p values <0.05 were considered statistically significant. RESULTS: The expression of repeated nicotine-induced locomotor sensitization was dose-dependently attenuated by MEGR, and 180 mg/kg/d MEGR significantly inhibited augmented accumbal DA release induced by a direct local challenge of nicotine. Moreover, 180 mg/kg/d MEGR reversed increases in malondialdehyde production, decreases in superoxide dismutase and catalase activities, and the reduced expression of nuclear factor erythroid 2-related factor 2 and heme oxygenase 1 in the nicotine-sensitized Nacc. CONCLUSIONS: These results suggest that MEGR inhibited nicotine-induced locomotion and dopaminergic sensitization via antioxidant action.

Hypothalamic Norepinephrine Mediates Acupunctural Effects on Hypothalamic-Pituitary-Adrenal Axis During Ethanol Withdrawal.

A previous study demonstrated that acupuncture at ST36 (Zu-San-Li) attenuates ethanol withdrawal (EW)-induced hyperactivation of the hypothalamic-pituitary-adrenal axis in rats. The current study investigated the involvement of hypothalamic norepinephrine (NE) in that process. Rats were intraperitoneally treated with 3 g/kg/d of ethanol or saline for 28 days. After 24 hours of EW, acupuncture was applied to rats at bilateral ST36 points or at nonacupoints (tail) for 1 minute. A high-performance liquid chromatography analysis showed that EW significantly increased both the NE and the 3-methoxy-4-hydroxy-phenylglycol (MHPG) levels in the hypothalamic paraventricular nucleus (PVN). Western blot analysis also revealed that EW markedly elevated the phosphorylation rates of tyrosine hydroxylase (TH), but spared TH protein expression in the PVN. However, acupuncture at ST36, but not at nonacupoints, greatly inhibited the increase in the hypothalamic NE, MHPG, and phosphorylation rates of TH. Additionally, postacupuncture infusion of NE into the PVN significantly attenuated the inhibitory effects of acupuncture at ST36 on the oversecretion of plasma corticosterone during EW. These results suggest that acupuncture at ST36 inhibits EW-induced hyperactivation of the hypothalamic NEergic system to produce therapeutic effects on the hypothalamic-pituitary-adrenal axis.

Acupuncture Attenuates Anxiety-Like Behavior by Normalizing Amygdaloid Catecholamines during Ethanol Withdrawal in Rats.

Previously, we demonstrated acupuncture at acupoint HT7 (Shen-Men) attenuated ethanol withdrawal syndrome by normalizing the dopamine release in nucleus accumbens shell. In the present study, we investigated the effect of acupuncture on anxiety-like behavior in rats and its relevant mechanism by studying neuro-endocrine parameters during ethanol withdrawal. Rats were treated with 3 g kg(-1)day(-1) of ethanol (20%, w/v) or saline by intraperitoneal injections for 28 days. The rats undergoing ethanol withdrawal exhibited anxiety-like behavior 72 h after the last dose of ethanol characterized by the decrease of time spent in the open arms of the elevated plus maze compared with the saline-treated rats (P < .05). Radioimmunoassay exhibited there were notably increased concentrations of plasma corticosterone in ethanol-withdrawn rats compared with saline-treated rats (P < .05). Additionally, high performance liquid chromatography analysis also showed the levels of norepinephrine and 3-methoxy-4-hydroxy-phenylglycol were markedly increased while the levels of dopamine and 3,4-dihydroxyphenylacetic acid were significantly decreased in the central nucleus of the amygdala of ethanol-withdrawn rats compared with saline-treated rats (P < .01). Acupuncture groups were treated with acupuncture at acupoint HT7 or PC6 (Nei-Guan). Acupuncture at HT7 but not PC6 greatly attenuated the anxiety-like behavior during ethanol withdrawal as evidenced by significant increases in the percentage of time spent in open arms (P < .05). In the meantime, acupuncture at HT7 also markedly inhibited the alterations of neuro-endocrine parameters induced by ethanol withdrawal (P < .05). These results suggest that acupuncture may attenuate anxiety-like behavior during ethanol withdrawal through regulation of neuro-endocrine system.