Bcl-2 hijacks the arsenic trioxide resistance in SH-SY5Y cells.

Aresenic trioxide (ATO) is proven to be active against leukaemia cells by inducing apoptosis and differentiation. Even though ATO could effectively induce remissions of leukaemia cells, the drug resistance was observed occasionally. To further dissect the mechanism of ATO resistance, we selected the ATO-resistant SH-SY5Y cells and found that Bcl-2 controlled the sensitivity of ATO in SH-SY5Y cells. We report that necroptosis, autophagy, NF-ƘB and MAPK signalling pathway are not involved in ATO-induced apoptosis. Moreover, the ATO-resistant cells showed distinct mitochondrial morphology compared with that of ATO-sensitive cells. Intriguingly, nude mice-bearing ATO-sensitive cells derived xenograft tumours are more sensitive to ATO treatment compared with that of ATO-resistant cells. These data demonstrate that cancer cells can acquire the ATO-resistance ability by increasing the Bcl-2 expression.

O­GlcNAcylation contributes to intermittent hypoxia­associated vascular dysfunction via modulation of MAPKs but not CaMKII pathways.

Intermittent hypoxia (IH) leads to vascular dysfunction, and O­linked­ß­N­acetylglucosamine (O­GlcNAc)ylation may regulate vascular reactivity through the modulation of intracellular signaling. The present study hypothesized that O­GlcNAc modifications contributed to the vascular effects of acute IH (AIH) and chronic IH (CIH) through the MAPK and Ca2+/calmodulin­dependent kinase II (CaMKII) pathways. Rat aortic and mesenteric segments were incubated with DMSO, O­GlcNAcase (OGA) or O­GlcNAc transferase (OGT) inhibitor under either normoxic or AIH conditions for 3 h, and arterial function was then assessed. Meanwhile, arteries isolated from control and CIH rats were exposed to 3 h of incubation under normoxic conditions using DMSO, OGA or OGT as an inhibitor, before assessing arterial reactivity. CIH was found to increase the expression of vascular O­GlcNAc protein and OGT, phosphorylate p38 MAPK and ERK1/2, and decrease OGA levels, but it had no effects on phosphorylated CaMKII levels. OGA inhibition increased global O­GlcNAcylation and the phosphorylation of p38 MAPK, ERK1/2 and CaMKII, whereas OGT blockade had the opposite effects. OGA inhibition preserved acetylcholine­induced relaxation in AIH arteries, whereas OGT blockade attenuated the relaxation responses of arteries under normoxic conditions or undergoing AIH treatments. However, the impairment of acetylcholine dilation in CIH mesenteric arteries was improved. CIH artery contraction was increased following angiotensin II (Ang II) exposure. Blockade of p38 MAPK and ERK1/2, but not CaMKII, attenuated Ang II­induced contractile responses in CIH arteries isolated from the non­OGT inhibitor­treated groups. OGT inhibition significantly blocked contractile responses to Ang II and abolished the inhibitory effects of MAPK inhibitors. These findings indicated that O­GlcNAcylation regulates IH­induced vascular dysfunction, at least partly by modulating MAPK, but not CaMKII, signaling pathways.

Arsenic trioxide induces gasdermin E mediated pyroptosis in astroglioma cells.

BACKGROUND: Arsenic trioxide (ATO) has been proved useful for the treatment of acute promyelocytic leukemia (APL). Apoptosis is the result of the cytotoxic effect of ATO, apoptotic mediated cell death confirmed by DNA fragmentation and Annexin V staining. Although signaling associated with ATO-induced apoptosis has been well defined, it is still unknown whether other forms of cell death are involved in ATO-induced cell death. METHODS: Western blotting, cytotoxicity assay, transmission electron microscopy were used to evaluate other forms of cell death in U251 cells. RESULTS: We found that pyroptotic mediated cell death was observed in U251 cells after ATO treatment, which was confirmed by observing the increased gasdermin E (GSDME) cleavage, lactate dehydrogenase (LDH) release and transmission electron microscopy imaging. Consistent with previous results, caspase-3 was activated by ATO, which was also important for GSDME cleavage and subsequent pyroptosis. CONCLUSIONS: We reported that GSDME mediated pyroptosis involved in ATO induced cell death in astroglioma cells.

A cellular delivery system fabricated with autologous BMSCs and collagen scaffold enhances angiogenesis and perfusion in ischemic hind limb.

Although therapeutic cellular angiogenesis is effective for chronic ischemia, the optimal mode of cellular administration is still under exploration. This study aimed to develop a cellular delivery system to enhance the perfusion and angiogenesis in the ischemic hind limb. Collagen scaffold (CS) was prepared, and for morphology and toxicity analysis, bone marrow-derived mesenchymal stem cells (BMSCs) were isolated, expanded, filtrated, and seeded onto CS to construct BMSCs-CS. The ischemic hind limbs of rabbit models were implanted with autologous BMSCs-CS, CS, and autologous BMSCs; the untreated ischemic or normal animals were considered as the ischemic or normal control groups. Oxygen saturation parameters were regularly measured to determine the perfusion in the extremities. Histological examinations with hematoxylin and eosin immunostaining against von Willebrand factor and smooth muscle (SM) α-actin were performed for capillary and mature vessel evaluation. CS was a multiporous structure without cytotoxicity. At several intervals, the oxygen saturation ratio (OSR) in normal control was the highest. The OSRs in BMSCs-CS and CS were higher than that in BMSCs and ischemic control (p < 0.05); the OSR in BMSCs-CS group was higher than that in CS at 6 and 8 weeks (p < 0.05). The capillaries in BMSCs-CS and CS were higher than that in CS, BMSCs, and the ischemic or normal control (p < 0.05). The mature vessels in BMSCs-CS were higher than that in CS, BMSCs, and the ischemic or normal control (p < 0.05). The autologous cellular delivery system proved to be an effective approach for improving higher ischemic hind limb perfusion and angiogenesis as opposed to cellular therapy alone.