Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) exhibits potent antitumor activity via membrane receptors on cancer cells without deleterious side effects for normal tissue. Unfortunately, breast cancer cells, as many other cancer types, develop resistance to TRAIL; therefore, TRAIL sensitizing agents are currently being explored. 2-Tellurium-bridged β-cyclodextrin (2-TeCD) is a synthetic organotellurium compound, with both glutathione peroxidase-like catalytic ability and thioredoxin reductase inhibitor activity. In the present study, we reported that 2-TeCD sensitized TRAIL-resistant human breast cancer cells and xenograft tumors to undergo apoptosis. In vitro, 2-TeCD efficiently sensitized MDA-MB-468 and T47D cells, but not untransformed human mammary epithelial cells, to TRAIL-mediated apoptosis, as evidenced by enhanced caspase activity and poly (adenosine diphosphate-ribose) polymerase cleavage. From a mechanistic standpoint, we showed that 2-TeCD treatment of breast cancer cells significantly upregulated the messenger RNA and protein levels of TRAIL receptor, death receptor (DR) 5, in a transcription factor Sp1-dependent manner. 2-TeCD treatment also suppressed TRAIL-induced nuclear factor-κB (NF-κB) prosurvival pathways by preventing cytosolic IκBα degradation, as well as p65 nuclear translocation. Consequently, the combined administration suppressed anti-apoptotic molecules that are transcriptionally regulated by NF-κB. In vivo, 2-TeCD and TRAIL were well tolerated in mice and their combination significantly inhibited growth of MDA-MB-468 xenografts and promoted apoptosis. Upregulation of DR5 and downregulation of NF-κB by the dual treatment were also observed in tumor tissues. Overall, 2-TeCD sensitizes resistant breast cancer cells to TRAIL-based apoptosis in vitro and in vivo. These findings provide strong evidence for the therapeutic potential of this combination against breast cancers.
Interleukin‐7(IL‐7) can regulate proliferation and apoptosis of cell and also regulate tumor lymphangiogenesis, but whether it regulating autophagy of tumor cells is not well known. We study the relationship between IL‐7 and some autophagy‐related markers, Beclin 1 and mammalian target of rapamycin (mTOR) and the mechanism of IL‐7 in regulating autophagy of human lung cancer cells. We detected expression of Beclin 1 and mTOR in lung cancer cells and their impact on the prognosis of lung cancer patients. Using Western blot and Reverse Transcription PCR, we found that IL‐7 activates PI3 K/Akt/mTOR signaling pathway by downregulated the expression of Beclin 1 in lung cancer cell lines. In addition, the expressions of Beclin 1 and mTOR were well correlated with clinical stages and survival of human non‐small cell lung cancer (NSCLC) patients. IL‐7R, mTOR, and tumor stage were the independent prognosticators in lung cancer. Taken together, our results provided evidence that IL‐7 activates PI3 K/Akt/mTOR signaling pathway via Beclin 1 to regulate autophagy in lung cancer cells.
BackgroundHuperzine A (HupA) is a selective acetylcholinesterase inhibitor used to treat Alzheimer’s disease. The existing dosage of HupA lacks brain selectivity and can cause serious side effects in the gastrointestinal and peripheral cholinergic systems.PurposeThe aim of this study was to develop and characterize a HupA nanoemulsion (NE) and a targeted HupA-NE modified with lactoferrin (Lf) for intranasal administration.MethodsThe NE was formulated using pseudo-ternary phase diagrams and optimized with response surface methodology. Particle size distribution and zeta potential were evaluated, and transmission electron microscopy was performed. We investigated the transport mechanisms of HupA-NEs into hCMEC/D3 cells, an in vitro model of the blood-brain barrier. HupA-NE, Lf-HupA-NE, and HupA solution were intranasally administered to rats to investigate the brain-targeting effects of these formulations. A drug targeting index (DTI) was calculated to determine brain-targeting efficiency.ResultsOptimized HupA-NE had a particle size of 15.24±0.67 nm, polydispersity index (PDI) of 0.128±0.025, and zeta potential of −4.48±0.97 mV. The composition of the optimized HupA-NE was 3.00% isopropyl myristate (IPM), 3.81% Capryol 90, and 40% Cremophor EL + Labrasol. NEs, particularly Lf-HupA-NE, were taken up into hCMEC/D3 cells to a greater extent than pure drug alone. Western blot analysis showed that hCMEC/D3 cells contained P-glycoprotein (P-gp), breast cancer resistance protein (BCRP), and multidrug resistance associated protein 1 (MRP1) transporters. The likely mechanisms resulting in higher NE transport to the brain were uptake by specific transporters and transcytosis. In vivo, intranasal Lf-HupA-NE significantly enhanced drug delivery to the brain compared to HupA-NE, which was confirmed by differences in pharmacokinetic parameters. The DTI of Lf-HupA-NE (3.2±0.75) demonstrated brain targeting, and the area under the curve for Lf-HupA-NE was significantly higher than that for HupA-NE.ConclusionLf-HupA-NE is a promising nasal drug delivery carrier for facilitating delivery of HupA to the central nervous system.
Bletilla striata is widely used for stanching bleeding. In this study, polysaccharides from B. striata (BSP) were extracted by hot water. Four polysaccharides named BSP-1−BSP-4 were fractionated using DEAE-52 cellulose. BSP fractions contained sulfate, and the degrees of substitution of BSP-3 and BSP-4 were 1.59 and 1.70, respectively. Analysis of monosaccharide composition showed that four polysaccharides were mainly composed of mannan and glucose. The in vitro results showed that BSP-1−BSP-4 elicited pro-coagulant capacities by shortening the activating partial thromboplastin time, prothrombin time, and thrombin time and elevating the fibrinogen content. Immunomodulatory activity was evaluated by MTT assay, the pinocytic capacity and NO production. Although BSP fractions did not affect RAW 264.7 cell viability, they, especially BSP-2, enhanced the immunomodulatory activity by increasing the pinocytic capacity and NO production. Overall, BSP may be developed as a potential coagulant with immunomodulatory effects.
Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) induces cell death in various types of cancer cells but has little or no effects on normal cells. Unfortunately, not all cancer cells respond to TRAIL; therefore, TRAIL sensitizing agents are currently being explored. Here, we reported that 6-(4-N,N-Dimethylaminophenyltelluro)-6-deoxy-β-cyclodextrin (DTCD), a cyclodextrin-derived diorganyl telluride which has been identified as an excellent inhibitor of thioredoxin reductase (TrxR), could sensitize TRAIL resistant human ovarian cancer cells to undergo apoptosis. In vitro, DTCD enhanced TRAIL-induced cytotoxicity in human ovarian cancer cells through up-regulation of DR5. Luciferase analysis and CHIP assays showed that DTCD increased DR5 promoter activity via Sp1 activation. Additionally, DTCD stimulated extracellular signal-regulated kinase (ERK) activation, while the ERK inhibitor PD98059 blocked DTCD-induced DR5 expression and suppressed binding of Sp1 to the DR5 promoter. We further demonstrated that DTCD could induce the release of ASK1 from its complex with Trx-1, and recovered its kinase activity. Meanwhile, suppression of ASK1 by RNA interference led to decreased ERK phosphorylation induced by DTCD. The underlying mechanisms reveal that Trx-1 is heavily oxidized in response to DTCD treatment, in accordance with the fact that DTCD could inhibit the activity of TrxR that reduces oxidized Trx-1. Moreover, using an A2780 xenograft model, DTCD plus TRAIL significantly inhibited the growth of tumor in vivo. Our results suggest that Trx/TrxR system inhibition may play a critical role in apoptosis by combined treatment with DTCD and TRAIL, and raise the possibility that their combination may be a promising strategy for ovarian carcinoma treatment.
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