Effect of oxymatrine on interferon-gamma and tumor necrosis factor-alpha serum levels in an experimental rat model of autoimmune encephalomyelitis

BACKGROUND： Studies have demonstrated that experimental autoimmune encephalomyelitis （EAE） onset correlates with increased interferon-v （IFN-γ） and tumor necrosis factor-α （TNF-α） expression. Oxymatrine （OM） has been shown to inhibit autoimmune responses, but there are no reports showing that it could prevent the development of EAE. OBJECTIVE： To observe the effect of OM on serum levels of IFN-γ and TNF-α in a rat model of EAE.DESIGN, TIME AND SETTING： A randomized, controlled, animal study was performed at the Experimental Animal Center of Henan Academy of Chinese Medicine and at the Key Disciplines Laboratory Clinical Medicine of Henan Province between July and December 2008. MATERIALS： OM was purchased from Chia-tai Tianqing Pharmaceutical, China; complete Freund＇s adjuvant was purchased from Sigma, USA. METHODS： Forty female Wistar rats were randomly assigned to four groups： EAE model （M）, low-dose OM treatment （OM-L）, high-dose OM treatment （OM-H）, and normal control （N, no immunization）, with 10 rats in each group. EAE was established in the M, OM-L, and OM-H groups following immunization with Guinea pig spinal cord homogenate and complete Freund＇s adjuvant. The M and N groups were intraperitoneally injected with normal saline （6.7 mL/kg per day）, the OM-L group received an intraperitoneal injection of OM （100 mg/kg per day）, and the OM-H group received OM （150 mg/kg per day）. MAIN OUTCOME MEASURES： At 16 days after immunization, the degree of histopathological changes in the spinal cord was assessed by hematoxylin-eosin stanining. Enzyme-linked immunosorbent assay was used to detect serum levels of IFN-γ, and radioimmunoassay was utilized to determine serum TNF-α level. Neurological scores were measured on a daily basis according to a 0-5 scale. RESULTS： Daily injections of OM, both high and low doses, resulted in decreased neurological scores in EAE rats （P〈0.01）, as well as reduced cellular infiltration in the spinal cord and decreased levels of serum IFN-γ and TNF-α （P〈 0.01）. CONCLUSION： OM reduced the onset and severity of EAE, which correlated with decreased IFN-γ and TNF-α expression.

RICTOR/mTORC2 affects tumorigenesis and therapeutic efficacy of mTOR inhibitors in esophageal squamous cell carcinoma

Dysregulation of mTORCl/mTORC2 pathway is observed in many cancers and mTORC1 inhibitors have been used clinically in many tumor types;however,the mechanism of mTORC2 in tumorigenesis is still obscure.Here,we mainly explored the potential role of mTORC2 in esophageal squamous cell carcinoma(ESCC)and its effects on the sensitivity of cells to mTOR inhibitors.We demonstrated that RICTOR,the key factor of mTORC2,and p-AKT(Ser473)were excessively activated in ESCC and their overexpression is related to lymph node metastasis and the tumor-node-metastasis(TNM)phase of ESCC patients.Furthermore,we found that mTORCl/mTORC2 inhibitor PP242 exhibited more efficacious anti-proliferative effect on ESCC cells than mTORC1 inhibitor RAD001 due to RAD001-triggered feedback activation of AKT signal.Another,we demonstrated that down-regulating expression of RICTOR in ECa109 and EC9706 cells inhibited proliferation and migration as well as induced cell cycle arrest and apoptosis.Noteworthy,knocking-down stably RICTOR significantly suppresses RAD001-induced feedback activation of AKT/PRAS40 signaling,and enhances inhibition efficacy of PP242 on the phosphorylation of AKT and PRAS40,thus potentiates the antitumor effect of RAD001 and PP242 both in vitro and in vivo.Our findings highlight that selective targeting mTORC2 could be a promising therapeutic strategy for future treatment of ESCC.

Inhibiting autophagy enhances sulforaphane-induced apoptosis via targeting NRF2 in esophageal squamous cell carcinoma

Sulforaphane(SFN), a natural anti-tumor compound from cruciferous vegetables, has been reported to induce protective autophagy to cancer cells, which might impair the anti-tumor efficiency of SFN. However, the accurate function and mechanism of SFN inducing autophagy in cancers are still obscure, especially in esophageal squamous cell carcinoma(ESCC), one of malignancies with high incidence in North China. Here, we mainly explored the potential function of autophagy upon SFN treatment in ESCC and molecular mechanism. We demonstrated that SFN could inhibit cell proliferation and induce apoptosis by activating caspase pathway. Moreover, we found activation of NRF2 pathway by SFN was responsible for the induction of autophagy and also a disadvantage element to the anti-tumor effects of SFN on ESCC, indicating that SFN might induce protective autophagy in ESCC. We, therefore,investigated effects of autophagy inhibition on sensitivity of ESCC cells to SFN and found that chloroquine(CQ) could neutralize the activation of SFN on NRF2 and enhance the activation of SFN on caspase pathway, thus improved the anti-tumor efficiency of SFN on ESCC in vitro and in vivo. Our study provides a preclinical rationale for development of SFN and its analogs to the future treatment of ESCC.