Glutathione (GSH) and GSH-related enzymes constitute the most important defense system that protects cells from free radical, radiotherapy, and chemotherapy attacks. In this study, we aim to explore the potential role and regulatory mechanism of the GSH redox cycle in drug resistance in glioblastoma multiforme (GBM) cells. We found that temozolomide (TMZ)-resistant glioma cells displayed lower levels of endogenous reactive oxygen species and higher levels of total antioxidant capacity and GSH than sensitive cells. Moreover, the expression of glutathione reductase (GSR), the key enzyme of the GSH redox cycle, was higher in TMZ-resistant cells than in sensitive cells. Furthermore, silencing GSR in drug-resistant cells improved the sensitivity of cells to TMZ or cisplatin. Conversely, the over-expression of GSR in sensitive cells resulted in resistance to chemotherapy. In addition, the GSR enzyme partially prevented the oxidative stress caused by pro-oxidant Lbuthionine -sulfoximine. The modulation of redox state by GSH or L-buthionine -sulfoximine regulated GSR-mediated drug resistance, suggesting that the action of GSR in drug resistance is associated with the modulation of redox homeostasis. Intriguingly, a trend toward shorter progress-free survival was observed among GBM patients with high GSR expression. These results indicated that GSR is involved in mediating drug resistance and is a potential target for improving GBM treatment.

Background: Ursolic acid is a promising anticancer agent. The current study aims to evaluate the single-and multiple-dose pharmacokinetics (PK) as well as the safety of ursolic acid nanoliposomes (UANL) in healthy volunteers and in patients with advanced solid tumors. Methods: Twenty-four healthy volunteers in the single-dose PK study were divided into three different groups, which received 37, 74, and 98 mg/m 2 of UANL. Eight patients in the multiple-dose PK study were administered with 74 mg/m 2 of UANL daily for 14 days. The UA plasma concentrations were determined using ultra-performance liquid chromatograph-tandem mass spectrometry. Results:The plasma concentration profiles of all subjects were characterized by a biexponential decline after infusion. The mean peak plasma concentration (C max ) increased linearly as a function of the dose (r = 0.999). The mean area under the plasma concentration-time curve (AUC) from 0 to 16 hours also increased proportionally with dose escalation (r = 0.998). However, the clearance was constant over the specific dose interval. In the multiple-dose PK study, the trough and average concentrations remained low. The mean AUC, half-life, C max , time to C max , and the volume of distribution on the first day were similar to those on the last day. All subjects tolerated the treatments well. Most UANL-associated adverse events varied from mild to moderate. Conclusions: UANL exhibits relatively linear PK behavior with dose levels from 37 mg/m 2 to 98 mg/m 2 . No drug accumulation was observed with repeated doses of UANL. The intravenous infusion of UANL was well tolerated by healthy volunteers and patients with advanced tumors.

Silkworm cocoon was recorded to cure carbuncle in the Compendium of Materia Medica. Previous studies have demonstrated that the supplemental silk protein sericin exhibits anticancer activity. In the present study, we investigated the effects of silk fibroin peptide (SFP) extracted from silkworm cocoons against human lung cancer cells in vitro and in vivo and its possible anticancer mechanisms. SFP that we prepared had high content of glycine (~ 30%) and showed a molecular weight of ~ 10 kDa. Intragastric administration of SFP (30 g/kg/d) for 14 days did not affect the weights, vital signs, routine blood indices, and blood biochemical parameters in mice. MTT assay showed that SFP dose-dependently inhibited the growth of human lung cancer A549 and H460 cells in vitro with IC values of 9.921 and 9.083 mg/mL, respectively. SFP also dose-dependently suppressed the clonogenic activity of the two cell lines. In lung cancer H460 xenograft mice, intraperitoneal injection of SFP (200 or 500 mg/kg/d) for 40 days significantly suppressed the tumor growth, but did not induce significant changes in the body weight. We further examined the effects of SFP on cell cycle and apoptosis in H460 cells using flow cytometry, which revealed that SFP-induced cell cycle arrest at the S phase, and then promoted cell apoptosis. We demonstrated that SFP (20-50 mg/mL) dose-dependently downregulates Bcl-2 protein expression and upregulates Bax protein in H460 cells during cell apoptosis. The results suggest that SFP should be studied further as a novel therapeutic agent for the treatment of lung cancer.

The novel pyrazoline derivative, BHX, has recently been shown to exhibit potent anti-tumour activity by blocking the Wnt/β-catenin signalling pathway. However, its effect on breast cancer growth and invasion are unknown. Our results show that BHX suppresses MDA-MB-231 cell viability and colony formation in a dose-dependent manner, and induces apoptosis and G0/G1 phase arrest. BHX-treated breast cancer cells showed morphological characteristics of cells undergoing apoptosis. Furthermore, BHX inhibited cell migration and invasion, which was associated with increased E-cadherin mRNA and protein expression, and down-regulation of SNAIL and vimentin. In addition, BHX induced the generation of intracellular ROS and decreased β-catenin protein and mRNA expression. We used a mouse xenograft model to investigate the effects of BHX in vivo, where the growth of MDA-MB-231 xenografted tumours was suppressed in nude mice treated continuously with BHX for 21 days. Finally, the rat plasma concentration of BHX was measured by ultra-performance liquid-chromatography tandem mass spectrometry and the pharmacokinetic parameters of BHX were processed by non-compartmental analysis. In conclusion, BHX merits further study as a novel therapeutic small molecule for the treatment of breast cancer.

BackgroundWnt/β-catenin signaling is a highly conserved pathway in organism evolution and is important in many biological processes. Overactivation of Wnt/β-catenin signaling is closely related to tumor development and progression. To identify potent small molecules that can fight aberrant Wnt/β-catenin-mediated cancer, we synthesized a novel pyrazoline derivative (N-(4-hydroxybenzyl)-1,3,4-triphenyl-4,5-dihydro-1H-pyrazole-5-carboxamide, BHX) to block Wnt signaling, and determined the absolute configuration of its precursor (ethyl 1,3,4-triphenyl-4,5-dihydro-1H-pyrazole-5-carboxylate). We then evaluated the inhibitory effect of BHX in vitro and in vivo.ResultsCell proliferation was assessed in three human cancer cell lines (A549, HT29, and MGC803) in the presence and absence of BHX using MTS assays. BHX effectively inhibited A549, HT29, and MGC803 cell proliferation with IC50 of 5.43 ± 1.99, 6.95 ± 0.24, and 7.62 ± 1.31 μM, respectively. BHX significantly induced apoptosis and G1 phase arrest in A549 and MGC803 cells. The β-catenin protein level was markedly reduced in A549 and MGC803 cells under BHX treatment. The inhibitory effect of BHX in vivo was investigated using a mouse xenograft model. A549 xenograft growth was suppressed by 50.96% in nude mice treated continuously with 100 mg/kg BHX for 21 d. Weight remained almost unchanged, which indicates the low toxicity of the compound.ConclusionsOur data suggest that BHX is a new drug candidate for cancer treatment because of its potent effect on the Wnt/β-catenin pathway and low toxicity.