Yantao Han

Trend of histone deacetylase inhibitors in cancer therapy: isoform selectivity or multitargeted strategy.

Pharmacological inhibition of histone deacetylases (HDACs) has been successfully applied in the treatment of a wide range of disorders, including Parkinsons disease, infection, cardiac diseases, inflammation, and especially cancer. HDAC inhibitors (HDACIs) have been proved to be effective antitumor agents by various stages of investigation. At present, there are two opposite focuses of HDACI design in the cancer therapy, highly selective inhibitor strategy and dual‐ or multitargeted inhibitors. The former method, which is supposed to elucidate the function of individual HDAC and provide candidate inhibitors with fewer side effects, has been widely accepted by the inhibitor developer. The latter approach, though less practiced, has promising potential for the antitumor therapy based on HDACIs. Effective HDACIs, some of which are in clinic anticancer research, have been developed by both methods. In order to gain insight into HDACI design, the strategies and achievements of the two diverse methods are reviewed.

Protective effect of L-carnitine against H2O2-induced neurotoxicity in neuroblastoma (SH-SY5Y) cells

Abstract Objectives: 4-N-trimethylammonium-3-hydroxybutyric acid (L-carnitine) is an endogenous mitochondrial membrane compound and some studies have reported that L-carnitine could effectively protect various cells against oxidative injury both in vitro and in vivo. In the present study, we used the human neuroblastoma SH-SY5Y cell line as an in vitro model and assessed the effect of L-carnitine on hydrogen peroxide (H2O2)-mediated oxidative stress and neurotoxicity. Methods: Cells in culture were treated with different concentrations of H2O2 alone or pretreated with L-carnitine. 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assays, transmission electron microscopy, agarose gel electrophoresis, biochemical methods, and Western blotting were employed in the present study. Results: Pretreatment with L-carnitine for 3 hours inhibited H2O2-induced cell viability loss, morphological changes, intracellular reactive oxygen species generation, and lipid peroxidation in a concentration-dependent manner. Endogenous anti-oxidant defense components including total anti-oxidative capacity, glutathione peroxidase, catalase, and superoxide dismutase were also promoted by L-carnitine. Meanwhile, H2O2-induced down-regulation of Bcl-2, up-regulation of Bax, and DNA damage and apoptosis were also inhibited in the presence of L-carnitine. Discussion: Taken together, these results suggest that L-carnitine may function as an anti-oxidant to inhibit H2O2-induced oxidative stress as well as regulation of Bcl-2 family and prevent the apoptotic death of neuronal cells, which might be beneficial for the treatment of oxidative stress in neurodegenerative diseases.

Hispidulin inhibits proliferation and enhances chemosensitivity of gallbladder cancer cells by targeting HIF-1α.

Gallbladder cancer (GBC) is an aggressive malignancy of the bile duct, which is associated with a low (5-year) survival and poor prognosis. The transcription factor HIF-1α is implicated in the angiogenesis, cell survival, epithelial mesenchymal transition (EMT) and invasiveness of GBC. In this study, we have investigated the role of HIF-1α in the pathobilogy of GBC and effect of hispidulin on the molecular events controlled by this transcription factor. We observed that hispidulin caused induction of apoptosis, blockade of growth and cell cycle progression in GBC cells. Our results have demonstrated for the first time that hispidulin-exerted anti-tumor effect involved the suppression of HIF-1α signaling. Hispidulin was found to repress the expression of HIF-1α protein dose-dependently without affecting the HIF-1α mRNA expression. In addition, the inhibition of HIF-1α protein synthesis was revealed to be mediated through the activation of AMPK signaling. Hispidulin also sensitized the tumor cells to Gemcitabine and 5-Fluoroucil by down-regulating HIF-1α/P-gp signaling. Given the low cost and exceedingly safe profile, hispidulin appears to be a promising and novel chemosensitizer for GBC treatment.

L-carnitine attenuates H2O2-induced neuron apoptosis via inhibition of endoplasmic reticulum stress.

Both oxidative stress and endoplasmic reticulum stress (ER stress) have been linked to pathogenesis of neurodegenerative diseases. Our previous study has shown that L-carnitine may function as an antioxidant to inhibit H2O2-induced oxidative stress in neuroblastoma SH-SY5Y cells. To further explore the neuroprotection of L-carnitine, here we study the effects of L-carnitine on the ER stress response in H2O2-induced SH-SY5Y cell injury. Our results showed that L-carnitine pretreatment could increase cell viability; inhibit apoptosis and ROS accumulation caused by H2O2 or tunicamycin (TM). L-carnitine suppress the endoplasmic reticulum dilation and activation of ER stress-associated proteins including glucose-regulated protein 78 (GRP78), CCAAT/enhancer-binding protein-homologous protein (CHOP), JNK, Bax and Bim induced by H2O2 or TM. In addition, H2O2-induced cell apoptosis and activation of ER stress can also be attenuated by antioxidant N-acetylcysteine (NAC), CHOP siRNA and the inhibitor of ER stress 4-phenylbutyric acid (4-PBA). Taken together, our results demonstrated that H2O2 could trigger both oxidative stress and ER stress in SH-SY5Y cells, and ER stress participated in SH-SY5Y apoptosis mediated by H2O2-induced oxidative stress. CHOP/Bim or JNK/Bim-dependent ER stress signaling pathways maybe related to the neuroprotective effects of L-carnitine against H2O2-induced apoptosis and oxidative injury.

Physcion inhibits the metastatic potential of human colorectal cancer SW620 cells in vitro by suppressing the transcription factor SOX2

Aim:Physcion, an anthraquinone derivative, exhibits hepatoprotective, anti-inflammatory, anti-microbial and anti-cancer activities. In this study we examined whether and how physcion inhibited metastatic potential of human colorectal cancer cells in vitro.Methods:Human colorectal cancer cell line SW620 was tested. Cell migration and invasion were assessed using a wound healing and Transwell assay, respectively. The expression levels of transcription factor SOX2 in the cells were modulated with shRNA targeting SOX2 and SOX2 overexpressing plasmid. The expression of target molecules involved in epithelial-mesenchymal transition (EMT) process and the signaling pathways was determined with Western blots or qRT-PCR. ROS levels were measured using DCF-DA.Results:Physcion (2.5, 5 mol/L) did not affect the cell viability, but dose-dependently inhibited the cell adhesion, migration and invasion. Physcion also inhibited the EMT process in the cells, as evidenced by the increased epithelial marker E-cadherin expression, and by decreased expression of mesenchymal markers N-cadherin, vimentin, fibronectin and α-SMA, as well as transcriptional repressors Snail, Slug and Twist. Physcion suppressed the expression of SOX2, whereas overexpression of SOX2 abrogated the inhibition of physcion on metastatic behaviors. Physcion markedly increased ROS production and phosphorylation of AMPK and GSK3β in the cells, whereas the AMPK inhibitor compound C or the ROS inhibitor NAC abolished the inhibition of physcion on metastatic behaviors.Conclusion:Physcion inhibits the metastatic potential of human colorectal cancer cells in vitro via activating ROS/AMPK/GSK3β signaling pathways and suppressing SOX2.

Hispidulin Potentiates the Antitumor Effect of Sunitinib Against Human Renal Cell Carcinoma in Laboratory Models

The aim of the study was to evaluate the effect of the hispidulin, a naturally occurring flavonoid, in combination with a new multi-targeted oral medication, sunitinib on renal cell carcinoma (RCC) cell proliferation in vitro and on tumor growth in vivo. After treatment with hispidulin or sunitinib, either alone or in combination, MTT assay was used to examine cell viability and flow cytometry analysis was employed to examine cell cycle distribution and apoptosis of the RCC cell lines 786-0 and Caki-1. Western blotting was employed to examine the expression of proteins related to pStat3 signaling pathway. Furthermore, a xenograft mouse model was applied to study the antitumor efficacy of sunitinib or hispidulin alone or in combination, with immunohistochemistry to detect expression of proteins related to xenograft growth and angiogenesis. Hispidulin dose-dependently inhibited proliferation and induced apoptosis in both of the tested RCC cell lines when used alone; when combined with sunitinib, relatively low concentration of hispidulin enhanced the antitumor activity of the latter. The antitumor activity of hispidulin and its enhancement of the antitumor activity of sunitinib correlated with the suppression of pStat3 signaling and the consequent downregulation of Bcl-2 and survivin. Moreover, combination of hispidulin and sunitinib inhibited the growth and angiogenesis of xenografts generated from Caki-1 significantly. Immunohistochemistry indicated decreased expression of proteins promoting xenograft growth and angiogenesis after combination treatment of hispidulin and sunitinib. Our results showed that hispidulin, by inhibiting pStat3 signaling, exhibited antitumor activity and the joint use of hispidulin and sunitinib could provide greater antitumor efficacy compared to either drug alone. Therefore, combination treatment with hispidulin and sunitinib might offer a novel therapeutic option for patients with RCC.

Oral Hepatoprotective Ability Evaluation of Purple Sweet Potato Anthocyanins on Acute and Chronic Chemical Liver Injuries

In recent years, chemical liver injury cases increased significantly in Asian countries, and the imbalance in redox system was believed to be the main cause. Purple sweet potato anthocyanins (PSPA) have been shown to exert antioxidant activity and oxidative-stress-associated functional protein modulation through various signaling pathways, so it is considered to have the potential of liver injury preventive activity. In order to evaluate the hepatoprotective potency of PSPA according to its free radical scavenging and antioxidant effects, three acute chemical liver injury models were set up with ethanol, acetaminophen and carbon tetrachloride. PSPA at moderate and high doses obviously attenuated the tested serum biomarker levels and liver index in our experiments. Besides, one chronic liver injury model set up with carbon tetrachloride was also applied, in which PSPA was orally administrated after the liver damage had been formed. Both the serum biomarker levels and histopathological analysis showed that PSPA was able to attenuated chronic liver injury. Our experimental results demonstrated the potential of PSPA as an oral hepatoprotective agent against chemical liver injury from food plant.

Modulation of oxidized-LDL receptor-1 (LOX1) contributes to the antiatherosclerosis effect of oleanolic acid.

Oleanolic acid (OA) is a bioactive pentacyclic triterpenoid. The current work studied the effects and possible mechanisms of OA in atherosclerosis. Quails (Coturnix coturnix) were treated with high fat diet with or without OA. Atherosclerosis was assessed by examining lipid profile, antioxidant status and histology in serum and aorta. Human umbilical vein endothelial cells (HUVECs) were exposed to 200μg/mL ox-LDL for 24h, then cell viability was assessed with MTT assay; reactive oxygen species (ROS) was assessed with DCFDA staining. Expression levels of LOX-1, NADPH oxidase subunits, nrf2 and ho-1 were measured with real time PCR and western blotting. Furthermore, LOX-1 was silenced with lentivirus and the expression levels assessment was repeated. OA treatment improved the lipid profile and antioxidant status in quails fed with high fat diet. Histology showed decreased atherosclerosis in OA treated animals. Ox-LDL exposure decreased viability and induced ROS generation in HUVECs, and this progression was alleviated by OA pretreatment. Moreover, elevated expression of LOX-1, NADPH oxidase subunits, nrf2 and ho-1 were observed in ox-LDL exposed HUVECs. OA pretreatment prevented ox-LDL induced increase of LOX-1 and NADPH oxidase subunits expression, while further increased nrf2 and ho-1 expression. Silencing of LOX-1 abolished ox-LDL induced effects in cell viability, ROS generation and gene expression. OA could alleviate high fat diet induced atherosclerosis in quail and ox-LDL induced cytotoxicity in HUVECs; the potential mechanism involves modulation of LOX-1 activity, including inhibition of expression of NADPH oxidase subunits and increase of the expression of nrf2 and ho-1.

Molecular mechanism of polypeptides from Chlamys farreri (PCF)’s anti-apoptotic effect in UVA-exposed HaCaT cells involves HSF1/HSP70, JNK, XO, iNOS and NO/ROS

This study investigated the molecular mechanisms of polypeptides from Chlamys farreri (PCF)s anti-apoptotic effects in ultraviolet A-rays (UVA) exposed HaCaT cells. UVA-induced apoptosis in HaCaT cells was confirmed with Hoechst 33258 fluorescent staining; PCF treatment inhibited UVA-induced apoptosis in HaCaT cells, increased transcriptional activities of heat shock factor protein 1 (HSF1) and the expression of heat shock protein 70 (HSP70), whereas inhibited activation of c-Jun N-terminal kinases (JNK), expression of xanthine oxidese (XO), inducible nitric oxide synthase (iNOS) and release of nitric oxide (NO)/reactive oxygen species (ROS). Meanwhile, the HSF1 transcription inhibitor quercetin increased UVA-induced apoptosis, activation of JNK, expression of XO and iNOS and release of NO/ROS. Among the two NO release peaks we found in UVA exposed HaCaT cells, XO inhibitor oxypurinol was found to be able to inhibit NO release at 3h post UVA exposure but not 18h, while iNOS inhibitor S-methylisothiourea sulfate (SMT) was found to inhibit iNOS expression and NO release at 18h but not 3h. PCFs protection against UVA-induced apoptosis in HaCaT cells involves increased transcriptional activity of HSF1, increased expression of HSP70, and the subsequential inhibition of JNK pathway, XO and iNOS expression and ROS/NO release.

Polypeptide from Chlamys farreri suppresses ultraviolet-B irradiation-induced apoptosis through restoring ER redox homeostasis, scavenging ROS generation, and suppressing the PERK-eIF2a-CHOP pathway in HaCaT cells

OBJECTIVE The aim of this study was to investigate the effect of polypeptide from Chlamys farreri (PCF) on ultraviolet B (UVB) irradiation-induced apoptosis in human keratinocyte HaCaT cells. METHODS HaCaT cells were treated with 20 mJ/cm(2) UVB irradiation for 18 h. The cell viability was measured by MTT assay, and apoptosis was detected with Hoechst 33258 staining and caspase-3 activity detection. Protein expression levels were assessed by Western blot analysis, and the intracellular ROS levels were also measured. RESULTS Our results from the MTT assay showed that UVB irradiation significantly declined the viability of HaCaT cells, which could be restored by PCF treatment. PCF decreased the apoptosis rate in HaCaT cells treated with UVB irradiation. Moreover, PCF increased the expression levels of PDI and Ero-1a, and scavenged the intracellular ROS. Furthermore, PCF inhibited the expressions of GRP78, p-PERK, p-eIF2a, and CHOP, and suppressed the ER stress-induced apoptosis, in UVB-irradiated HaCaT cells. In addition, the ROS scavenging effect of 4-PBA was less potent than PCF, indicating that ER stress-related ROS production contribute partially to the total ROS level, and ER was not the only target of PCF treatment. CONCLUSIONS Our results indicate that PCF inhibits UVB irradiation-induced apoptosis through restoring ER redox homeostasis and suppressing the PERK-eIF2a-CHOP pathway. These findings provide evidence for the application of PCF in the protection of skin from UV irradiation.