Zeyao Tang

SZC017, a novel oleanolic acid derivative, induces apoptosis and autophagy in human breast cancer cells.

Oleanolic acid (OA) and its derivatives such as 2-cyano-3,12-dioxoolean-1,9-dien-28-oic acid (CDDO), CDDO-Me, and CDDO-Im show potent anticancer function. In this study, we elucidated the anticancer effect of SZC017, a novel OA derivative and identified the mechanisms by which SZC017 induces MCF-7 cell death. We found that SZC017 effectively decreased the cell viability of these breast cancer cells, but was less toxic to MCF10A mammary epithelial cells. Mechanisms underlying the inhibition of cell viability are apoptosis, autophagy induction, and G0/G1 phase arrest. SZC017 treatment suppressed the levels of Akt, phosphorylated-Akt (p-Akt), p-IκBα, total p65, and total p-p65, in addition to p-p65 in both the cytoplasm and nucleus. Furthermore, the inhibition of p65 nuclear translocation was confirmed by immunofluorescence staining. Cell viability was increased after pretreatment with chloroquine, an inhibitor of autophagy, whereas the level of procaspase-3 was significantly decreased. A concentration-dependent increase in the intracellular reactive oxygen species (ROS) level was observed in both MCF-7 and MDA-MB-231 cells. Additionally, pretreatment with N-acetyl-l-cysteine (NAC), a ROS scavenger, increased cell viability and the expression of Akt and procaspase-3, but decreased the ratio of LC3-II/I. These data show that SZC017 is an effectively selective anticancer agent against breast cancer cells, highlighting the potential use of this derivative as a breast cancer therapeutic agent.

Phosphocreatine protects endothelial cells from Methylglyoxal induced oxidative stress and apoptosis via the regulation of PI3K/Akt/eNOS and NF-κB pathway.

Methylglyoxal (MGO), an active metabolite of glucose, can cause cellular injury which has an affinity for the progression of diabetes-associated atherosclerosis. Phosphocreatine (PCr) is a well-known high-energy phosphate compound. However, its protective effects and mechanism in the formation of a diabetes-associated atherosclerosis have not been clarified. In the present study, we investigated whether PCr could prevent MGO-induced apoptosis in human umbilical vascular endothelial cells (HUVECs) and explored the possible mechanisms. Cells were pre-treated with PCr and then stimulated with MGO. Cell morphology, cytotoxicity and apoptosis were assessed by light microscopy, MTT assay, and Annexin V-FITC respectively. Apoptotic-related proteins were evaluated by Western blotting. Reactive oxygen species (ROS) generation, intracellular calcium and mitochondrial membrane potential (MMP) were measured with fluorescent probes. Our results showed that PCr dose-dependently prevented MGO associated HUVEC cytotoxicity and suppressed MGO activated ROS generation as well as apoptotic biochemical changes such as lactate dehydrogenase, malondialdehyde leakage, loss of MMP, decreased Bcl-2/Bax protein ratio, levels of caspase-3 and 9. In addition, the antiapoptotic effect of PCr enhanced p-Akt/Akt protein ratio, NO synthase (eNOS) activation, NO production and cGMP levels and also was partially suppressed by a PI3K inhibitor (LY294002). Furthermore, PCr also inhibited MGO-induced transcriptional activity of Nuclear factor kappa B (NFκB). In conclusion, our data described that PCr exerts an antiapoptotic effect in HUVECs exposed to oxidative stress by MGO through the mitochondrial pathway and the modulation of PI3K/Akt/eNOS and NF-κB signaling pathway. Thus, it might be a candidate therapeutic agent for diabetic-associated cardiovascular diseases.

EGCG protects against homocysteine-induced human umbilical vein endothelial cells apoptosis by modulating mitochondrial-dependent apoptotic signaling and PI3K/Akt/eNOS signaling pathways

Homocysteine (Hcy) induced vascular endothelial injury leads to the progression of endothelial dysfunction in atherosclerosis. Epigallocatechin gallate (EGCG), a natural dietary antioxidant, has been applied to protect against atherosclerosis. However, the underlying protective mechanism of EGCG has not been clarified. The present study investigated the mechanism of EGCG protected against Hcy-induced human umbilical vein endothelial cells (HUVECs) apoptosis. Methyl thiazolyl tetrazolium assay (MTT), transmission electron microscope, fluorescent staining, flow cytometry, western blot were used in this study. The study has demonstrated that EGCG suppressed Hcy-induced endothelial cell morphological changes and reactive oxygen species (ROS) generation. Moreover, EGCG dose-dependently prevented Hcy-induced HUVECs cytotoxicity and apoptotic biochemical changes such as reducing mitochondrial membrane potential (MMP), decreasing Bcl-2/Bax protein ratio and activating caspase-9 and 3. In addition, EGCG enhanced the protein ratio of p-Akt/Akt, endothelial nitric oxide synthase (eNOS) activation and nitric oxide (NO) formation in injured cells. In conclusion, the present study shows that EGCG prevents Hcy-induced HUVECs apoptosis via modulating mitochondrial apoptotic and PI3K/Akt/eNOS signaling pathways. Furthermore, the results indicate that EGCG is likely to represent a potential therapeutic strategy for atherosclerosis associated with Hyperhomocysteinemia (HHcy).

Anticancer effect of SZC015 on lung cancer cells through ROS-dependent apoptosis and autophagy induction mechanisms in vitro.

Oleanolic acid (OA) and its several derivatives possess various pharmacological activities, such as antitumor and anti-inflammation. In present study, anticancer effect of SZC015, an OA derivative, and its underlying mechanisms were investigated. We demonstrated that cell viability was significantly decreased in SZC015-treated lung cancer cells, but has less cytotoxicity in human bronchial epithelial cell line. Further investigation verified that apoptosis and autophagy induction and G0/G1 phase arrest were observed in SZC015-treated H322 cells. Mechanically, the level of Akt, p-Akt, p-IκBα, and total p65, the p-p65 in the cytoplasm and nucleus were suppressed by SZC015 in H322 cells, respectively. Inhibition of p65 nuclear translocation was also confirmed by immunofluorescence staining. In addition, co-treatment with chloroquine, an autophagy inhibitor, significantly inhibited SZC015-induced autophagy and enhanced SZC015-induced apoptotic cell death. Intracellular ROS was increased in a concentration-dependent manner, which could be prevented by N-Acetyl l-Cysteine, an ROS scavenger. Moreover, the level of Akt and procaspase-3 were increased, while the ratio of LC3 II/I was decreased. Taken together, our study demonstrates that the inhibitory effect of SZC015 against H322 cells is mediated by excessive ROS generation that could suppress Akt/NF-κB signaling pathway, which thereby leads to apoptotic and autophagic cell death.

Erratum to: Phosphocreatine protects against LPS-induced human umbilical vein endothelial cell apoptosis by regulating mitochondrial oxidative phosphorylation.

The original version of this article unfortunately contained a mistake. The arrow marks in Fig. 5 were incorrect. It is now corrected with this erratum. The correct version of Fig. 5 is given below. The authors apologise for this error and the inconvenience it has caused to the readers.

Anticancer effect of SZC017, a novel derivative of oleanolic acid, on human gastric cancer cells

Oleanolic acid (OA) and its several derivatives possess chemopreventive and chemotherapeutic functions against a series of cancer types. Many chemotherapeutic compounds are effective in improving the quality of life and prolonging the survival of patients with gastric cancer, therefore progress in the treatment of gastric cancer, especially the anticancer effects of OA derivatives must be achieved. The inhibitory effect of SZC017, a newly synthesized derivative of OA, on cell viability was determined by MTT assay. Furthermore, flow cytometry, transmission electron microscopy, and western blot analysis revealed that the inhibition of cell viability by OA was mediated by triggering the intrinsic apoptosis of gastric cancer cells, and inducing S phase arrest of SGC7901 cells. Mechanistically, SZC017 was effective against gastric cancer cells via inhibiting Akt/NF‑κB signaling and topoisomerase I and IIα proteins. Taken together, our data indicate that SZC017 may be a potential chemotherapeutic agent against gastric cancer cells.

Protective effects of dioscin against fructose-induced renal damage via adjusting Sirt3-mediated oxidative stress, fibrosis, lipid metabolism and inflammation

In the present work, the effects and possible mechanisms of dioscin, one natural product from the famous vegetable Dioscoreae rhizoma (Shanyao in Chinese), against high fructose-induced renal injury in rats were tested. The results showed that dioscin significantly restored fructose-induced renal injury by decreasing the levels of Cr, BUN, and rehabilitating histopathological changes. In addition, dioscin markedly adjusted the levels of MDA, SOD and GSH-Px, reduced ROS level in renal tissue, and decreased the levels of TG, FFA, α-SMA and COL1A. Mechanistic study showed that dioscin significantly up-regulated the expression levels of Sirt3, SOD2, and then suppressed inflammation by decreasing the expression levels of NF-kB, HMGB1, c-Jun, c-Fos, COX2, TNF-α, IL-1β and IL-6. Furthermore, dioscin-caused high levels of Sirt3 and SOD2 attenuated oxidative stress by regulating the expression levels of Nrf2, GST, Keap1, regulated lipid metabolism by controlling the expression levels of SREBP-1c, SCD-1, FASn, ACC, CPT1, and adjusted TGF-β1/Smad signal to inhibit renal fibrosis. In summary, dioscin showed protective effects against fructose-induced renal damage via adjusting Sirt3-mediated oxidative stress, renal fibrosis, lipid metabolism and inflammation, which should be considered as one candidate to treat renal injury in the future. We also suggest that the patients with renal injury can take more Shanyao for the therapy and treatment.

Induction of autophagy by an oleanolic acid derivative, SZC017, promotes ROS-dependent apoptosis through Akt and JAK2/STAT3 signaling pathway in human lung cancer cells.

The signal transducers and activators of transcription 3 (STAT3) signaling pathway is a common feature in many solid tumors including non‐small cell lung cancer, whereas current therapies usually fail to treat this disease in majority of cases. In the present study, we aimed to investigate the cytotoxic effect and the underlying mechanisms of SZC017, an oleanolic acid derivative, on human lung cancer cells. Cell viability was significantly decreased in SZC017‐treated lung cancer cells. Mechanistically, SZC017 reduced A549 cell viability by activating both apoptosis and autophagy pathways. SZC017 was able to inhibit the phosphorylation of Akt, JAK2, and STAT3 in A549 cells, resulting in the inactivation of Akt and JAK2/STAT3 signaling pathways. In addition, SZC017 could induce ROS generation and Ca2+ release. Pretreatment with N‐Acetyl L‐Cysteine, a ROS scavenger, could fully reverse SZC017‐induced ROS and increase the expression of Akt, p‐STAT3, and procaspase‐3, while decrease the ratio of LC3‐II/I and the expression of Beclin‐1. In summary, our study provides pharmacological evidence that SZC017 exhibits potential use in the treatment of lung cancer.

Anticancer effect of SZC015 on pancreatic cancer via mitochondria-dependent apoptosis and the constitutive suppression of activated nuclear factor κB and STAT3 in vitro and in vivo: SONG et al.

Pancreatic cancer is the fourth leading cause of cancer‐related death worldwide. Advances in therapeutic strategies such as chemotherapy have improved the clinical outcomes for pancreatic cancer patients. However, developing new therapeutic compounds against pancreatic cancer is still urgent due to the poor prognosis. Here, we show that SZC015, an oleanolic acid derivative, exhibits potent inhibitory effect on both pancreatic cancer cells in vitro and the corresponding xenograft tumors in vivo. Mechanistically, the activation of intrinsic apoptosis and G1 phase arrest resulting from mitochondria damage caused by SZC015 contribute significantly to the anticancer effects of SZC015. SZC015 also has remarkably inhibitory effects on the transcription factors that are extensively activated in pancreatic cancer tissues. As a constitutively activated transcription factor in pancreatic cancer, the nuclear factor κB is highly suppressed after SZC015 treatment in vitro or administration in vivo. Based on the bioinformatics analysis of microarray data, we validate that JAK2/STAT3 signaling is indeed activated in the human pancreatic cancer tissues and SZC015 also shows inhibitory effect on this signaling both in vitro and in vivo. These data suggest the potent effects of SZC015 on pancreatic cancer and also provided novel insights into the mechanisms of SZC015 as a new potent candidate for treating pancreatic cancer.