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Ginsenoside CK (GCK), as a metabolite of ginsenoside Rb1, has been studied for its anti-cancer activity. However, its in-depth anti-cancer mechanism on cervical cancer (CC) HeLa cells has not been fully elucidated. This study found that GCK inhibited the proliferation of CC HeLa cells and caused alteration in cell morphology with an IC50 of 45.95 μM. At the same time, GCK treatment blocked the cell cycle in the G0/G1 phase, elevated the reactive oxygen species (ROS) level, decreased mitochondrial membrane potential (Δψm), contributed to Ca2+ leakage, inhibited HeLa cell metastasis, and stimulated the key markers related to apoptosis, mitochondrial and endoplasmic reticulum pathways. GCK altered the regulation of the Caspase family, Bak/Bcl-xl and down-regulated the endoplasmic reticulum pathways (PERK and IRE1α). Starting from flow cytometry and the protein level, we found that autophagy inhibitors inhibited autophagy while promoting apoptosis, and apoptosis inhibitors reduced the rate of apoptosis while promoting autophagy, which proved that GCK can be used as a suitable novel natural product for CC treatment.

Purpose: Our previous studies have indicated that non-muscle myosin heavy chain IIA (NMMHC IIA) is involved in H 2 O 2 -induced neuronal apoptosis, which is associated with the positive feedback loop of caspase-3/ROCK1/MLC pathway. However, the neuroprotective effect of NMMHC IIA inhibition with an adeno-associated virus (AAV) vector after transient middle cerebral artery occlusion (MCAO) and its role in caspases-3/ROCK1/MLC pathway remain blurred., Methods: Green fluorescent protein (GFP) and a small hairpin RNA targeting Myh9 (encoding NMMHC IIA) were cloned and packaged into the AAV9 vector. AAV-shMyh9 or control vector were injected into C57BL/6J mice four weeks prior to 60 min MCAO. Twenty-four hours after reperfusion, functional and histological analyses of the mice were performed., Results: In this study, AAV-shMyh9 was used to down-regulate NMMHC IIA expression in mice. We found that down-regulation of NMMHC IIA could improve neurological scores and histological injury in ischemic mice. Ischemic attack also activated neuronal apoptosis, and this effect was partially attenuated when NMMHC IIA was inhibited by AAV-shMyh9. In addition, AAV-shMyh9 significantly reduced cerebral ischemic/reperfusion (I/R)-induced NMMHC IIA-actin interaction, caspase-3 cleavage, Rho-associated kinase1 (ROCK1) activation and myosin light-chains (MLC) phosphorylation., Conclusion: Consequently, we showed that AAV-shMyh9 inhibits I/R-induced neuronal apoptosis linked with caspase-3/ROCK1/MLC/NMMHC IIA-actin cascade, which has also been confirmed to be a positive feedback loop. These findings put some insights into the neuroprotective effect of AAV-shMyh9 associated with the regulation of NMMHC IIA-related pathway under ischemic attack and provide a therapeutic strategy for ischemic stroke., Competing Interests: The authors declare no conflicts of interest in this work., (© 2020 Wang et al.)

Methyl protodioscin (MPD) is a steroid saponin which has been well known for its pharmacological properties. Herein, we evaluated the anti-cancer activity of MPD for proliferation inhibition and apoptosis induction in Hela cells. MPD was purified from the rhizoma of Polygonatum sibiricum primarily and identified by HPLC, UPLC-TOF-MS/MS and NMR analysis, respectively. Results showed that MPD repressed cell proliferation at IC 50 of 18.49 μM, altered cell morphology, arrested the cell cycle in G2/M phase, facilitated the generation of intracellular ROS and led to cell apoptosis in a concentration-dependent manner. Furthermore, MPD treatment promoted death receptor pathway and mitochondrial pathway efficiently. The inhibition of Caspase-8 and Caspase-9 proteins in these pathways abolished the apoptosis significantly, further demonstrated the mechanism of MPD-induced apoptosis. These findings offer novel information that MPD may be considered as a possible natural anti-cancerous agent in the form of functional foods or medicinal products., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

The molecular mechanism of Juglone-induced cell cycle arrest and apoptosis in human endometrial cancer cells was investigated. Juglone was purified from the green husk of Carya cathayensis Sarg and identified by HPLC, LC-MS/MS, and NMR. At an IC 50 of 20.81 μM, juglone significantly inhibited Ishikawa cell proliferation, as shown by S phase arrest mediated by inactivation of cyclin A protein ( p < 0.05). The ROS levels increased significantly after exposure to juglone, which paralleled increases in the mRNA and protein expression of p21 and decreases in the levels of CDK2, cdc25A, CHK1, and cyclin A. The expression of Bcl-2 and Bcl-xL was significantly down-regulated, whereas the expression of Bax, Bad and cyto c was up-regulated, and we later confirmed the involvement of the mitochondrial pathway in juglone-induced apoptosis. Our in vitro results stated that juglone can be studied further as an effective natural anticancer agent.

The global morbidity and mortality of colorectal cancer (CRC) are ranked the third among gastrointestinal tumors in the world. MiR-451a is associated with several types of cancer, including CRC. However, the roles and mechanisms of miR-451a in CRC have not been elucidated. BAP31 is a predicted target gene of miR-451a in our suppression subtractive hybridization library. Its relationship with miR-451a and function in CRC are unclear. We hypothesized that miR-451a could induce apoptosis through suppressing BAP31 in CRC. Immunohistochemistry and real-time PCR were used to measure BAP31 expressions in CRC tissues and pericarcinous tissues from 57 CRC patients and CRC cell lines. Dual-luciferase reporter assay was used to detect the binding of miR-451a to BAP31. The expression of BAP31 protein in CRC tissues was significantly higher than that in pericarcinous tissues, which was correlated with distant metastasis and advanced clinical stages of CRC patients. The expression of BAP31 was higher in HCT116, HT29, SW620, and DLD cells than that in the normal colonic epithelial cell line NCM460. The expression of BAP31 was absolutely down-regulated when over-expressing miR-451a in HCT116 and SW620 cells compared with control cells. Mir-451a inhibited the expression of BAP31 by binding to its 5'-UTR. Over-expressing miR-451a or silencing BAP31 suppressed the proliferation and apoptosis of CRC cells by increasing the expressions of endoplasmic reticulum stress (ERS)-associated proteins, including GRP78/BIP, BAX, and PERK/elF2α/ATF4/CHOP, which resulted in increased ERS, cytoplasmic calcium ion flowing, and apoptosis of CRC cells. These changes resulting from over-expressing miR-451a were reversed by over-expressing BAP31 with mutated miR-451a-binding sites. Over-expressing miR-451a or silencing BAP31 inhibited tumor growth by inducing ERS. The present study demonstrated that miR-451a can inhibit proliferation and increase apoptosis through inducing ERS by binding to the 5'-UTR of BAP31 in CRC.

The effect of MTH1 inhibition on cancer cell survival has been elusive. Here we report that although silencing of MTH1 does not affect survival of melanoma cells, TH588, one of the first-in-class MTH1 inhibitors, kills melanoma cells through apoptosis independently of its inhibitory effect on MTH1. Induction of apoptosis by TH588 was not alleviated by MTH1 overexpression or introduction of the bacterial homolog of MTH1 that has 8-oxodGTPase activity but cannot be inhibited by TH588, indicating that MTH1 inhibition is not the cause of TH588-induced killing of melanoma cells. Although knockdown of MTH1 did not impinge on the viability of melanoma cells, it rendered melanoma cells sensitive to apoptosis induced by the oxidative stress inducer elesclomol. Of note, treatment with elesclomol also enhanced TH588-induced apoptosis, whereas a reactive oxygen species scavenger or an antioxidant attenuated the apoptosis triggered by TH588. Indeed, the sensitivity of melanoma cells to TH588 was correlated with endogenous levels of reactive oxygen species. Collectively, these results indicate that the cytotoxicity of TH588 toward melanoma cells is not associated with its inhibitory effect on MTH1, although it is mediated by cellular production of ROS., (Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.)

Ethylacetate extract of Tetrastigma hemsleyanum (EET) has a potent antitumor activity in vitro and in vivo. However, the molecular mechanism underlying EET-induced apoptosis remains elusive. As part of our continuing studies, we investigated the apoptosis mechanism of HepG2 cells exposed to different concentrations of EET in vitro. Confocal laser scanning was used to detect the apoptotic morphological changes. Flow cytometer and inverted fluorescence microscope were used to detect the mitochondrial membrane potential and cytosolic Ca(2+) level. Western blotting analysis was used to evaluate the expression of the apoptosis-related proteins. Annexin V/PI staining was used to investigate cell apoptosis. Spectrophotometry was used to detect the activity of caspase family. The results showed that distinct apoptotic morphological changes occurred in HepG2 cells treated by EET. EET caused collapse of mitochondrial membrane potential, elevation of cytosolic Ca(2+) level, and evoked release of cytochrome c from mitochondria in a concentration-dependent manner. The apoptosis was accompanied by a significant activation of caspase-3, caspase-9, and the cleavage of poly (ADP-ribose) polymerase, but there was no significant change in either the activity or the expression level of caspase-8. Furthermore, EET-induced apoptosis could be inhibited by caspase-9 inhibitor Z-LEHD-FMK but not by caspase-8 inhibitor Z-IETD-FMK. Taken together, these overall results demonstrated that EET-induced apoptosis of HepG2 cells was mediated by the mitochondrial caspase-dependent intrinsic pathway rather than the death receptor/caspase-8-mediated signaling route.

Background: Prolonged isolated thrombocytopenia (PT) is a frequent complication in patients who undergo allogeneic hematopoietic stem cell transplantation (allo-HSCT), and it is associated with an adverse prognosis. In this study, we hypothesized that desialylation on platelet surfaces was associated with PT after allo-HSCT. The mechanisms participating in this process may include NEU1 translocation, platelet apoptosis, and phagocytosis by macrophages., Methods: PT was defined as a peripheral platelet count less than 100 × 10(9)/L without sustained anemia or leukopenia for more than 3 months after allo-HSCT. 34 patients were identified consecutively from a cohort of 255 patients who underwent allo-HSCT for hematologic malignancies between May and October 2014 at Peking University Institute of Hematology. Desialylation, enzyme expression, and phagocytosis were detected using flow cytometry, immunofluorescence, RT-PCR, Western blot, and so on., Results: Platelets from the PT patients had significantly fewer sialic acids (P = .001) and increased β-galactose exposure indicative of desialylation on the surface (P = .042), and serum from the PT patients showed a higher sialic acid concentration (8.400 ± 0.2209 μmol/L, P < .001). The sialidase NEU1 was over-expressed from mRNA to protein levels, and its catalytic activity was increased in platelets from the PT patients. Desialylation of GPIbα in the PT patients was correlated with changes in 14-3-3ζ distribution, which, relative to Bad activation, modulated the expression of Bcl-2 family proteins, depolarized the inner membrane of the mitochondria, and initiated the intrinsic mitochondria-dependent pathway of apoptosis. Macrophages derived from the THP-1 cell line preferred to phagocytize desialylated platelets from the PT patients in vitro. We also revealed that oseltamivir (400 μmol/L) could inhibit 50 % of the sialidase activity on platelets and could protect 20 % of platelets from phagocytosis in vitro., Conclusions: Desialylation of platelets was associated with platelet apoptosis and phagocytosis, whereas oseltamivir could reduce platelet destruction in the periphery, indicating a potential novel treatment for PT after allo-HSCT.

We determined the effect of emodin on the lactate dehydrogenase (LDH) release, superoxide dismutase (SOD), glutathione (GSH), total antioxidant capacity (T-AOC), reactive oxygen species (ROS), mitochondria membrane potential (ΔΨm), and apoptosis in the hepatic cells of grass carp (Ctenopharyngodon idellus). Cultured cells were treated with different concentrations of emodin (0.04-25 μg/ml) for 24 h. We found that the cytotoxic effect of emodin was mediated by apoptosis, and that this apoptosis occurred in a dose-dependent manner. Emodin (1-25 μg/ml) significantly induced apoptosis accompanying by ΔΨm disruption and ROS generation and significantly reduced the SOD activities and T-AOC compared to the control. Thus, the oxidative effect of emodin may be attributed to the loss of the cell's ability to maintain the activity of its radical-scavenging enzymes. GSH was also significantly higher after 0.2-1 μg/ml emodin exposure, indicating that cells failed to maintain their redox balance when compensating for the increased oxidative stress. Our results suggest that emodin (1-25 μg/ml) exerts its cytotoxic effects via apoptosis by directly affecting the mitochondria., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

The hexokinase inhibitor 3-bromopyruvate (3-BrPA) can inhibit glycolysis in tumor cells to reduce ATP production, resulting in apoptosis. However, as 3-BrPA is an alkylating agent, its cytotoxic action may be induced by other molecular mechanisms. The results presented here reveal that 3-BrPA-induced apoptosis is caspase independent. Further, 3-BrPA induces the generation of reactive oxygen species in MDA-MB-231 cells, leading to mitochondria-mediated apoptosis. These results suggest that caspase-independent apoptosis may be induced by the generation of reactive oxygen species. In this study, we also demonstrated that 3-BrPA induces apoptosis through the downregulation of myeloid cell leukemia-1 (Mcl-1) in MDA-MB-231 breast cancer cells. The results of Mcl-1 knockdown indicate that Mcl-1 plays an important role in 3-BrPA-induced apoptosis. Further, the upregulation of Mcl-1 expression in 3-BrPA-treated MDA-MB-231 cells significantly increases cell viability. In addition, 3-BrPA treatment resulted in the downregulation of p-Akt, suggesting that 3-BrPA may downregulate Mcl-1 through the phosphoinositide-3-kinase/Akt pathway. These findings indicate that 3-BrPA induces apoptosis in breast cancer cells by downregulating Mcl-1 through the phosphoinositide-3-kinase/Akt signaling pathway.

Objective: Endothelial apoptosis plays an important role in the initiation of atherosclerosis. It would be useful to clarify whether activation of non-neuronal muscarinic receptor (NNMR) could prevent endothelial apoptosis and atherosclerosis. We investigated the effects of NNMR activation on regulating rat aortic endothelial cells (RAECs) apoptosis induced by homocysteine, an independent risk factor of atherosclerosis, and further studied its molecular mechanism., Methods: RAECs were incubated using homocysteine at the concentration of 2.7 mmol/L for 36 h. RAECs were also pre-treated with carbachol or arecoline to examine their effects. RT-PCR was used to assess changes in the gene expression related to cell apoptosis., Results: Incubation of RAECs with homocysteine at the concentration of 2.7 mmol/L resulted in morphologic changes, such as cellular shrinkage, membrane blebbing, chromatin condensation and margination. These could be attenuated by pretreatment with carbachol and arecoline at the concentration of 10 micromol/L for 12 h. Homocysteine induced apoptosis in RAECs and the molecular mechanisms were associated with the regulation of fas, fas-L and caspase-8 in the death receptor pathway, bcl-2, bcl-xL and bax in the mitochondrial pathway, caspase-12 in the endoplasmic reticulum pathway and caspase-3, caspase-6 and p53 as downstream effectors. Carbachol and arecoline attenuated the effects of homocysteine on genes in the death receptor pathway, in the mitochondrial pathway and in the downstream pathway. Atropine could reverse all of the effects of arecoline., Conclusion: Activation of NNMR by carbacol and arecoline inhibits homocysteine-induced endothelial cell apoptosis mainly through regulation of death receptor pathway, mitochondrial pathway and downstream effectors.

Omentin-1, a new adipokine released from adipose tissue, is associated with several key aspects of metabolic syndrome such as insulin sensitivity. However, it is not known whether omentin-1 affects cancer cell growth. In this study, we studied the influence of omentin-1 on two types of human hepatocellular carcinoma cells: HepG2 and HuH-7 cells. Cell viability assay showed that omentin-1 (1 and 2 μg/ml) significantly inhibited the proliferation of HepG2 and HuH-7 cells. Both annexin+PI staining and TUNEL assay showed that omentin-1 induced apoptosis in these cells. Moreover, omentin-1 treatment upregulated protein levels of p53 and p21, a main transcriptional target of p53. Interestingly, omentin-1 did not affect p53 mRNA level. Further mechanism study showed that omentin-1 upregulated p53 protein level through decreasing p53 deacetylation and thereby increasing the stability of p53 protein. Using small interfering RNA (siRNA)-mediated knockdown, we found that Sirt1 deacetylase, but not histone deacetylase 1 (HDAC1), was required for the effect of omentin-1 on p53 deacetylation and cancer cell proliferation. In omentin-1 treated HepG2 cells, the bax/bcl-2 protein ratio was increased, while the caspase-3 signaling pathway was also activated. Omentin-1 triggered JNK signaling but not p38 and ERK1/2 signaling pathways. Collectively, our data suggests that the novel adipokine omentin-1 may contribute to the therapeutic strategy for hepatocellular carcinoma., (Copyright © 2012 Elsevier B.V. All rights reserved.)

Background: Myelodysplastic syndromes (MDS) are a group of heterogeneous myeloid clonal disorders characterized by ineffective haematopoiesis and immune deregulation. Emerging evidence has shown the effect of bone marrow (BM) endothelial progenitor cells (EPCs) in regulating haematopoiesis and immune balance. However, the number and functions of BM EPCs in patients with different stages of MDS remain largely unknown.Methods: Patients with MDS (N = 30), de novo acute myeloid leukaemia (AML) (N = 15), and healthy donors (HDs) (N = 15) were enrolled. MDS patients were divided into lower-risk MDS (N = 15) and higher-risk MDS (N = 15) groups according to the dichotomization of the Revised International Prognostic Scoring System. Flow cytometry was performed to analyse the number of BM EPCs. Tube formation and migration assays were performed to evaluate the functions of BM EPCs. In order to assess the gene expression profiles of BM EPCs, RNA sequencing (RNA-seq) were performed. BM EPC supporting abilities of haematopoietic stem cells (HSCs), leukaemia cells and T cells were assessed by in vitro coculture experiments.Results: Increased but dysfunctional BM EPCs were found in MDS patients compared with HDs, especially in patients with higher-risk MDS. RNA-seq indicated the progressive change and differences of haematopoiesis- and immune-related pathways and genes in MDS BM EPCs. In vitro coculture experiments verified that BM EPCs from HDs, lower-risk MDS, and higher-risk MDS to AML exhibited a progressively decreased ability to support HSCs, manifested as elevated apoptosis rates and intracellular reactive oxygen species (ROS) levels and decreased colony-forming unit plating efficiencies of HSCs. Moreover, BM EPCs from higher-risk MDS patients demonstrated an increased ability to support leukaemia cells, characterized by increased proliferation, leukaemia colony-forming unit plating efficiencies, decreased apoptosis rates and apoptosis-related genes. Furthermore, BM EPCs induced T cell differentiation towards more immune-tolerant cells in higher-risk MDS patients in vitro. In addition, the levels of intracellular ROS and the apoptosis ratios were increased in BM EPCs from MDS patients, especially in higher-risk MDS patients, which may be therapeutic candidates for MDS patients.Conclusion: Our results suggest that dysfunctional BM EPCs are involved in MDS patients, which indicates that improving haematopoiesis supporting ability and immuneregulation ability of BM EPCs may represent a promising therapeutic approach for MDS patients. [ABSTRACT FROM AUTHOR]

Background: Docetaxel (DTX) exhibits antitumor effects against breast cancer by stabilizing microtubules and increasing the accumulation of reactive oxygen species (ROS). DTX extravasation during infusion often causes skin injury. The present study aimed to investigate the effects and mechanisms of icaritin (ICT) on DTX‐induced skin injury. Methods: The effects of ICT on the viability and apoptosis of HaCaT cells were measured by SRB assay and flow cytometry, respectively. Endogenous LC3 puncta and microtubules were determined by immunofluorescence. The number of mitochondria was measured by MitoTracker orange staining. ROS were determined by dihydroethidium staining. The expression of markers of ROS and autophagy were measured by western blotting. Chloroquine, compound D, and tamoxifen were employed as the inhibitor for autophagy and AMPK, estrogen receptors (ERs) modulator, respectively. Results: DTX inhibited the viability and decreased apoptosis of HaCaT cells, which can be rescued by ICT. ICT decreased microtubule bundles, increased the number of mitochondria, and attenuated ROS of HaCaT cells induced by DTX. ICT blocks autophagy and the autophagic flux. Compound C or tamoxifen diminished the protection effects of ICT on DTX‐treated HaCaT cells. Conclusion: ICT alleviates DTX‐induced skin injury by suppressing ROS, reducing microtubule bundles, and blocking autophagy via ERs. Our study indicated that ICT may be a potential candidate for DTX‐induced skin injury. [ABSTRACT FROM AUTHOR]

Bistability (coexistence of two stable steady states in a dynamical system) is a key mechanism of cellular decision‐making and has been observed in many biochemical reaction networks such as mitogen‐activated protein kinase (MAPK) signaling pathways. Theoretical studies have shown that bistability can arise in a single two‐site MAPK phosphorylation and dephosphorylation cycle. However, the bistable behavior mostly relies on the kinetic mechanisms and parameters of this two‐site modification. In exploring the system‐level properties of MAPK regulation, most models to date focus on two limiting reaction regimes, distributive and processive, and are characterized by high levels of parametric uncertainty. Here, we developed a combined kinetic method which applies a continuous spectrophotometric enzyme‐coupled assay incorporated with the viscosity approach, to perform detailed kinetic analyses of p38α MAPK dual phosphorylation by MKK6. Almost all kinetic rate constants for the first and second phosphorylation steps in p38α activation have been quantitatively determined, supporting that the phosphorylation occurs randomly in the first step, albeit preferring the tyrosine residue. The release rates of monophosphorylated p38α from MKK6, either as the product in the first modification or as the substrate in the second step, were comparable to the respective adjacent phosphoryl transfer steps. These results indicated that dual phosphorylation of p38α by MKK6 involves a random, partially processive mechanism. Based on the experimentally determined models and parameters, dynamics of the p38α‐MKK6‐MKP5 system were explored, demonstrating for the first time that bistability can arise with this model at biologically feasible parameter values. Enzymes: p38α (EC 2.7.11.24); MKK6 (EC 2.7.12.2). Almost all kinetic rate constants for the first and second phosphorylation steps in p38α activation have been quantitatively determined. Dynamics of the p38α‐MKK6‐MKP5 system were explored based on these experimentally determined models and parameters, demonstrating for the first time that bistability (coexistence of two stable steady states in a dynamical system) can arise with this model at biologically feasible parameter values. [ABSTRACT FROM AUTHOR]

Ethylacetate extract of Tetrastigma hemsleyanum (EET) has a potent antitumor activity in vitro and in vivo. However, the molecular mechanism underlying EET-induced apoptosis remains elusive. As part of our continuing studies, we investigated the apoptosis mechanism of HepG cells exposed to different concentrations of EET in vitro. Confocal laser scanning was used to detect the apoptotic morphological changes. Flow cytometer and inverted fluorescence microscope were used to detect the mitochondrial membrane potential and cytosolic Ca level. Western blotting analysis was used to evaluate the expression of the apoptosis-related proteins. Annexin V/PI staining was used to investigate cell apoptosis. Spectrophotometry was used to detect the activity of caspase family. The results showed that distinct apoptotic morphological changes occurred in HepG cells treated by EET. EET caused collapse of mitochondrial membrane potential, elevation of cytosolic Ca level, and evoked release of cytochrome c from mitochondria in a concentration-dependent manner. The apoptosis was accompanied by a significant activation of caspase-3, caspase-9, and the cleavage of poly (ADP-ribose) polymerase, but there was no significant change in either the activity or the expression level of caspase-8. Furthermore, EET-induced apoptosis could be inhibited by caspase-9 inhibitor Z-LEHD-FMK but not by caspase-8 inhibitor Z-IETD-FMK. Taken together, these overall results demonstrated that EET-induced apoptosis of HepG cells was mediated by the mitochondrial caspase-dependent intrinsic pathway rather than the death receptor/caspase-8-mediated signaling route. [ABSTRACT FROM AUTHOR]

• Dysregulated transcripts of irradiated human skin keratinocytes were identified by Microarray-based expression profiling. • These dysregulated transcripts were implicated in multiple pathways including type I interferon-mediated pathways. • Interferon α inducible protein 6 (IFI6) is induced by radiation in human skin cells and confers radio protection. • IFI6 is translocated into nucleus and regulating the transcriptional activity of HSF1. 5. A certain amount of potential HSF1-targeted genes upregulated by IFI6 overexpression post radiation is involved. Radiation-induced skin injury is one of the main adverse effects and a dose-limiting factor of radiotherapy without feasible treatment. The underlying mechanism of this disease is still limited. To investigate the potential molecular pathways and mechanisms of radiation-induced skin injury. mRNA expression profiles were determined by Affymetrix Human HTA2.0 microarray. IFI6 overexpression and knockdown were mediated by lentivirus. The functional changes of skin cells were measured by flow cytometry, ROS probe and Edu probe. Protein distribution was detected by immunofluorescence experiment, and IFI6-interacting proteins were detected by immunoprecipitation (IP) combined with mass spectrometry. The global gene changes in IFI6-overexpressed skin cells after irradiation were detected by RNA-seq. mRNA expression profiling showed 50 upregulated and 13 down regulated genes and interferon alpha inducible protein 6 (IFI6) was top upregulated. Overexpression of IFI6 promoted cell proliferation and reduced cell apoptosis as well as ROS production following radiation, and conversely, increased the radiosensitivity of HaCaT and human skin fibroblast (WS1). IFI6 was translocated into nucleus in irradiated skin cells and the interacting relationship with mitochondrial single-stranded DNA-binding protein 1 (SSBP1), which could enhance the transcriptional activity of heat shock transcription factor 1 (HSF1). IFI6 augmented HSF1 activity following radiation in HaCaT and WS1 cells. RNA-seq analysis showed IFI6 modulated virus infection and cellular response to stress pathways, which may help to further explore how IFI6 regulate the transcriptional activity of HSF1. This study reveals that IFI6 is induced by ionizing radiation and confers radioprotection in skin cells. [ABSTRACT FROM AUTHOR]

Three iridium(III) complexes were synthesized. The anticancer activity in vitro was investigated by cytotoxicity, apoptosis, ROS and mitochondrial membrane potential. • Three iridium(III) complexes were synthesized and characterized. • The stability of the complexes was determined by UV–Vis spectra. • The anticancer activity of the complexes was studied by cytotoxicity in vitro, apoptosis and western blot. • Intracellular ROS levels were assayed. Three new iridium(III) complexes [Ir(ppy) 2 (DBDPPZ)](PF 6) (1), [Ir(bzq) 2 (DBDPPZ)](PF 6) (2) and [Ir(piq) 2 (DBDPPZ)](PF 6) (3) were synthesized and characterization. The cytotoxicity in vitro of the complexes against several cancer cells was evaluated by MTT method. The complexes show high anticancer activity against MDA-DB231, SGC-7901, A549 and HeLa cells. In particular, complexes 1 , 2 and 3 exhibit very high cytotoxic effect on SGC-7901 cells with a very low IC 50 value of 1.53 ± 0.10, 0.17 ± 0.05 and 0.30 ± 0.03 μM, respectively. The cell colonies formation, intracellular ROS, mitochondrial membrane potential, intracellular Ca2+ levels were investigated under fluorescence microscope. Studies show that the complexes can inhibit cell colonies formation, increase intracellular ROS and Ca2+ levels, induce a decrease in the mitochondrial membrane potential. The apoptosis and cell cycle arrest were also studied by flow cytometry. Additionally, the complexes can regulate the expression of caspase 3 and Bcl-2 family proteins. Taken together, the complexes induce apoptosis in SGC-7901 cells through a ROS-mediated mitochondrial dysfunction pathway. [ABSTRACT FROM AUTHOR]