Apolipoprotein E2 inhibits mitochondrial apoptosis in pancreatic cancer cells through ERK1/2/CREB/BCL-2 signaling

Background: Apolipoprotein E2(ApoE2) is a pleiotropic protein that influences several aspects of cancer metabolism and development. Evading apoptosis is a vital factor for facilitating cancer cell growth. However, the role and mechanism of ApoE2 in regulating cell apoptosis of pancreatic cancer remain unclear. Methods: In this study, we firstly detected the m RNA and protein expressions of ApoE2 in PANC-1 and Capan-2 cells by real-time polymerase chain reaction and Western blotting. We then performed TUNEL and flow cytometric analyses to explore the role of recombinant human ApoE2, p CMV6-ApoE2 and si ApoE2 in the apoptosis of PANC-1 and Capan-2 cells. Furthermore, we investigated the molecular mechanism through which ApoE2 affected apoptosis in PANC-1 cells using immunofluorescence, immunoprecipitation, Western blotting and co-immunoprecipitation analysis. Results: ApoE2 phosphorylated ERK1/2 and inhibited pancreatic cancer cell apoptosis. In addition, our data showed that ApoE2/ERK1/2 altered the expression and mitochondrial localization of BCL-2 via activating CREB. ApoE2/ERK1/2/CREB also increased the total BCL-2/BAX ratio, inhibited the opening of the mitochondrial permeability transition pore and the depolarization of mitochondrial transmembrane potential, blocked the leakage of cytochrome-c and the formation of the apoptosome, and consequently, suppressed mitochondrial apoptosis. Conclusions: ApoE2 regulates the mitochondrial localization and expression of BCL-2 through the activation of the ERK1/2/CREB signaling cascade to evade the mitochondrial apoptosis of pancreatic cancer cells. ApoE2 may be a distinct prognostic marker and a potential therapeutic target for pancreatic cancer.

Apoptosis of colon cancer CT-26 cells induced polysaccharide from Cyclocarya paliurus and its phosphorylated derivative via intrinsic mitochondrial passway

In this study,the antitumor properties and the possible molecular mechanisms of Cyclocarya paliurus polysaccharide(CP)and its phosphorylated derivative(P-CP)on CT-26 mouse colon carcinoma cells were investigated.Results found that CP had high inhibition ratio against CT-26 cells.The flow cytometry results found that CP treatment could cause the intracellular acidification,arrest the cell cycle in the S phase and increase reactive oxygen species generation.Additionally,CP treatment triggered mitochondrial membrane potential depolarization and Ca^(2+)overloading,and broke down the balance of antioxidant system,Na^(+)/K^(+)-ATPase and Ca^(2+)-ATPase.Further analysis found CP induced cell apoptosis through improving the activities of caspase-3 and caspase-9,and increasing the level of cytochrome C.Furthermore,the comparative study of antitumor effect on CT-26 cells displayed that the phosphorylation enhanced antitumor activities of polysaccharides.These results suggest CP is a potential natural therapeutic agent for colon cancer and phosphorylation represents an effective method of enhancing the antitumor activity of CP.

Environmental hypoxia induces apoptosis in large yellow croaker Larimichthys crocea via both intrinsic and extrinsic pathways

Hypoxia has become an unfavorable factor affecting the sustainable development of the large yellow croaker Larimichthys crocea,an economically important mariculture fish in China.Apoptosis is a consequence of hypoxia on fish.However,the effects of hypoxia stress on apoptosis in L.crocea remain largely unknown.We investigated the effect of environmental hypoxia on apoptosis in L.crocea.Results show that hypoxia induced apoptosis in L.crocea both in vivo and in vitro.The mitochondrial membrane potential was significantly reduced in large yellow croaker fry(LYCF)cells.The expression levels of Bcell lymphoma/leukemia-2(Bcl-2)m RNA and protein were also significantly decreased in the liver and LYCF cells during 96 h and 48 h of hypoxia stress,respectively,whereas the expression level of Bcl-2 associated X(Bax)mRNA,Casp3 mRNA,and activity of caspase-3/7/9 were significantly increased,indicating that hypoxia induced caspase-dependent intrinsic apoptosis in L.crocea.The expression level of the apoptosis-inducing factor(AIF)protein was significantly increased in the liver and LYCF cells.The level of AIF protein was significantly decreased in the cytoplasm but increased in the nuclei of L.crocea,demonstrating that hypoxia induced the AIF-mediated caspase-independent intrinsic apoptosis.In addition,the activity of caspase-8 was significantly increased,indicating that hypoxia stress induced extrinsic apoptosis in L.crocea.Therefore,hypoxia induced apoptosis in L.crocea through both the intrinsic and extrinsic pathways.The present study accumulated basic biological information to help elucidate the mechanism of hypoxia response in marine fish.

Hippocampus protection from apoptosis by Baicalin in a LiClpilocarpine-induced rat status epilepticus model through autophagy activation

BACKGROUND Autophagy is associated with hippocampal injury following status epilepticus(SE)and is considered a potential therapeutic mechanism.Baicalin,an emerging multitherapeutic drug,has shown neuroprotective effects in patients with nervous system diseases due to its antioxidant properties.AIM To investigate the potential role of autophagy in LiCl-pilocarpine-induced SE.METHODS The drugs were administered 30 min before SE.Nissl staining showed that Baicalin attenuated hippocampal injury and reduced neuronal death in the hippocampus.Western blotting and terminal deoxynucleotidyl transferase dUTP nick end labeling assay confirmed that Baicalin reversed the expression intensity of cleaved caspase-3 and apoptosis in hippocampal CA1 following SE.Furthermore,western blotting and immunofluorescence staining were used to measure the expression of autophagy markers(p62/SQSTM1,Beclin 1,and LC3)and apoptotic pathway markers(cleaved caspase-3 and Bcl-2).RESULTS Baicalin significantly upregulated autophagic activity and downregulated mitochondrial apoptotic pathway markers.Conversely,3-methyladenine,a commonly used autophagy inhibitor,was simultaneously administered to inhibit the Baicalin-induced autophagy,abrogating the protective effect of Baicalin on the mitochondrial apoptotic level.CONCLUSION We illustrated that Baicalin-induced activation of autophagy alleviates apoptotic death and protects the hippocampus of SE rats.

Essential Oil from Siegesbeckia pubescens Induces Apoptosis through the Mitochondrial Pathway in Human HepG2 Cells

Siegesbeckia pubescens（SP） has been used as a traditional medicine for the treatment of and inflammatory diseases. However, the activities of SP against hepatocellular carcinoma and the related mechanisms remain unclear. The present study aimed to examine the effects of the essential oil of SP（SPEO） on the proliferation of hepatocellular carcinoma cells and the possible mechanisms. The growth inhibition of Hep G2 cells was analyzed by MTT assay. Hoechst 33258 and fluorescence microscopy were utilized to observe the nuclear morphological changes of apoptotic cells. Flow cytometry was used to detect cell apoptosis and cell cycle. The expressions of the target proteins were detected by Western blotting. The results showed that SPEO obviously inhibited the proliferation of Hep G2 cells in a dose-dependent manner. SPEO activated a series of apoptotic proteins in Hep G2 cells, increasing expression levels of Bax, caspase-3 and caspase-9, and decreasing the bcl-2 expression level. SPEO displayed promising anti-hepatocellular carcinoma activities in vitro, partly by inducing apoptosis in Hep G2 cells through activating the mitochondrial pathway.

Time representation of mitochondrial morphology and function after acute spinal cord injury

Changes in mitochondrial morphology and function play an important role in secondary damage after acute spinal cord injury. We recorded the time representation of mitochondrial morphology and function in rats with acute spinal cord injury. Results showed that mitochondria had an irregular shape, and increased in size. Mitochondrial cristae were disordered and mitochondrial membrane rupture was visible at 2–24 hours after injury. Fusion protein mitofusin 1 expression gradually increased, peaked at 8 hours after injury, and then decreased to its lowest level at 24 hours. Expression of dynamin-related protein 1, amitochondrial fission protein, showed the opposite kinetics. At 2–24 hours after acute spinal cord injury, malondialdehyde content, cytochrome c levels and caspase-3 expression were increased, but glutathione content, adenosine triphosphate content, Na＋-K＋-ATPase activity and mitochondrial membrane potential were gradually reduced. Furthermore, mitochondrial morphology altered during the acute stage of spinal cord injury. Fusion was important within the first 8 hours, but fission played a key role at 24 hours. Oxidative stress was inhibited, biological productivity was diminished, and mitochondrial membrane potential and permeability were reduced in the acute stage of injury. In summary, mitochondrial apoptosis is activated when the time of spinal cord injury is prolonged.

A Novel Schiff Base Zinc Coordination Compound Inhibits Proliferation and Induces Apoptosis of Human Osteosarcoma Cells

Various kinds of schiff base metal complexes have been proven to induce apoptosis of tumor cells. However,it remains largely unknown whether schiff base zinc complexes induce apoptosis in human cancer cells. Here,we synthesized a novel schiff base zinc coordination compound（SBZCC） and investigated its effects on the growth,proliferation and apoptosis of human osteosarcoma MG-63 cells. A novel SBZCC was synthesized by chemical processes and used to treat MG-63 cells. The cell viability was determined by CCK-8 assay. The cell cycle progression,mitochondrial membrane potential and apoptotic cells were analyzed by flow cytometry. The apoptosis-related proteins levels were determined by immunoblotting. Treatment of MG-63 cells with SBZCC resulted in inhibition of cell proliferation and cell cycle arrest at G1 phase. Moreover,SBZCC significantly reduced the mitochondrial membrane potential and induced apoptosis,accompanied with increased Bax/Bcl-2 and Flas L/Fas expression as well as caspase-3/8/9 cleavage. Our results demonstrated that the synthesized novel SBZCC could inhibit the proliferation and induce apoptosis of MG-63 cells via activating both the mitochondrial and cell death receptor apoptosis pathways,suggesting that SBZCC is a promising agent for the development as anticancer drugs.

Chinese herbal medicine Yougui Pill reduces exogenous glucocorticoid-induced apoptosis in anterior pituitary cells

Long-term glucocorticoid use may result in sustained suppression of one or more secreted components from the hypothalamo-pituitary-adrenal axis, and often results in apoptosis. Yougui Pill（YGP）, a 10-component traditional Chinese herbal medicine, has been shown to be clinically effective for glucocorticoid-induced suppression of the hypothalamo-pituitary-adrenal axis. However, the pharmacological and molecular mechanisms remain unclear. We hypothesized that YGP would exert an anti-apoptosis effect on dexamethasone-treated anterior pituitary cells. In vivo experiments showed that YGP significantly reduced the number of apoptotic cells, down-regulated m RNA expression of cytochrome c, caspase-3, and caspase-9, and up-regulated m RNA expression of Bcl-2. These findings suggest that YGP reduced glucocorticoid-induced apoptosis in rat anterior pituitary cells by regulating the mitochondria-mediated apoptosis pathway.

HSP70 inhibitor combined with cisplatin suppresses the cervical cancer proliferation in vitro and transplanted tumor growth:An experimental study

Objective:To study the regulating effect of HSP70 inhibitor(PES) combined with cisplatin on cervical cancer proliferation in vitro and transplanted tumor growth.Methods:Cervical cancer Hela cell lines were cultured and divided into control group,cisplatin group,PES group and cisplatin+PES group that were treated with serum-free DMEM,cisplatin with final concentration of 10 μmol/L,PES 20 μmol/L and cisplatin 10 μmol/L combined with PES with 20 μmol/L,respectively;animal models with cervical cancer xenografts were established and divided into control group,cisplatin group,PES group and cisplatin+PES group who received intra-tumor injection of normal saline,10 μmol/L cisplatin,20 μmol/L PES as well as 10 μmol/L cisplatin+20 μmol/L PES,respectively.Cell proliferation activity,transplanted tumor volume and mitochondria apoptosis molecule expression were detected.Results:Cell viability value and Bcl-2 mRNA expression in cells of cisplatin group,PES group and cisplatin+PES group were significantly lower than those of control group while Bax,Caspase-3 and Caspase-9 mRNA expression in cells were significantly higher than those of control group;transplanted tumor volume and the Bcl-2 mRNA expression in transplanted tumor tissue of cisplatin group,PES group and cisplatin+PES group were significantly lower than those of control group while Bax,Caspase-3 and Caspase-9 m RNA expression in transplanted tumor tissue were significantly higher than those of control group.Conclusions:HSP70 inhibitor combined with cislatin can inhibit cervical cancer cell proliferation in vitro and transplanted tumor growth through mitochondrial apoptosis pathway.

Combination of Total Astragalus Extract and Total Panax Notoginseng Saponins Strengthened the Protective Effects on Brain Damage through Improving Energy Metabolism and Inhibiting Apoptosis after Cerebral Ischemia-Reperfusion in Mice

Objective： To explore the effects and molecular mechanisms of the combination between total Astragalus extract （TAE） and total Panax notoginseng saponins （TPNS） against cerebral ischemia- reperfusion injury. Methods： C57BL/6 mice were randomly divided into sham-operated group, model group, TAE （110 mg/kg） group, TPNS （115 mg/kg） group, TAE-TPNS combination group and Edaravone （4 mg/kg） group, treated for 4 days, then, cerebral ischemia-repeffusion injury was established by bilateral common carotid artery （CCA） ligation for 20 min followed by reperfusion for 1 and 24 h. Results： TPNS could increase adenosine triphosphate （ATP） level, TAE and TAE-TPNS combination increased ATP, adenosine diphosphate （ADP） contents and Na＋-K＋-ATPase activity, and the effects of TAE-TPNS combination were stronger than those of TAE or TPNS alone after reperfusion for 1 h. After reperfusion for 24 h, TAE, TPNS and TAE-TPNS combination significantly increased neurocyte survival rate and decreased the apoptosis rate as well as down-regulated the expression of phosphorylated c-June N-terminal kinasel/2 （p-JNK1/2）, cytochrome C （Cyt C）, cysteine aspartic acid-specific protease （Caspase）-9 and Caspase-3. Furthermore, the effects in TAE-TPNS combination were better than those in TAE or TPNS alone. Conclusion： The combination of TAE 110 mg/kg and TPNS 115 mg/kg could strengthen protective effects on cerebral ischemia injury, the mechanism underlying might be related to improving jointly the early energy metabolism, and relieving the delayed apoptosis via inhibiting the mitochondrial apoptosis pathway of JNK signal transduction.

Upconversion nano-photosensitizer targeting into mitochondria for cancer apoptosis induction and cyt c fluorescence monitoring

Disruption of mitochondrial reactive oxygen species （mitoROS） plays a major role in cancer cell apoptosis. Here, we designed a core/shell-structured mitochondriatargeting upconversion-based nano-photosensitizer （TPP-UC（PS）） with a lanthanidedoped upconversion nanoparticle （UCNP） core coated by a photosensitizer （PS）-incorporated dense silica shell. Following irradiation with external nearinfrared laser （NIR）, TPP-UC（PS） in mitochondria caused serious mitochondrial matrix swelling for the activated upconversion-based photodynamic therapy （UC-PDT）, and the mobilization of cytochrome c （cyt c） was amplified in response to the increased mitoROS. Specifically, this heme-containing cyt c could be monitored by varying TPP-UC（PS）＇s upconversion luminescence signal （UCL）, which may facilitate the in situ detection of cyt c for apoptosis research. As a proof of concept, our designed TPP-UC（PS） may provide significant opportunities for controlling cancer cell apoptosis under NIR stimulation and for studying apoptosis using the dynamic UCL, which is influenced by local cyt c.

Xuezhikang(血脂康) Reduced Renal Cell Apoptosis in Streptozocin-Induced Diabetic Rats through Regulation of Bcl-2 Family

Objective： To investigate the effect of Xuezhikang（血脂康, XZK） on renal cell apoptosis in diabetic rats and the possible mechanism. Methods： Sixty-six rats were randomly divided into 3 groups： the normal, model and XZK groups. In each group, the rats were further randomly divided into 3-month and 6-month subgroups, respectively. Diabetes of rats was induced by a single intraperitoneal injection of 1% streptozocin at 60 mg/kg body weight. Rats in the XZK group received gastric perfusion of XZK（1200 mg/kg body weight） everyday for 3 or 6 months, while rats in the normal and model groups received equal volume of saline. Twenty-four hours＇ urine was collected for urinary albumin excretion（UAE） measurement. Periodic acid-Schiff（PAS） and Masson＇s trichrome staining were used for saccharides and collagen detection. Cell apoptosis of renal cortex was investigated by Td T-mediated d UTP nick end labeling（TUNEL） staining. Bax and Bcl-2 expressions were detected by immunohistochemistry and Western blot, respectively. Cytochrome C（Cyt C） and caspase-9 concentration were detected by Western blot. Results： Compared with the model group, XZK treatment could significantly decrease the kidney hypertrophy index, 24 h UAE, renal cell apoptosis, cytoplasmic Cyt C level and active caspase-9 level, as well as suppress the increment of Bax and up-regulate the expression of Bcl-2, leading to the suppression of Bax/Bcl-2 ratio at 3 and 6 months（P〈0.05 or P〈0.01）. Moreover, XZK treatment could alleviate the deposition of PAS-stained saccharides and Masson＇s trichromestained collagen to different extent. Conclusions： Renal cell apoptosis was observed in diabetic kidney, in which mitochondrial apoptotic pathway might be involved. XZK treatment could attenuate pathological changes in diabetic kidney and reduce renal cell apoptosis, probably via the suppression of Bax/Bcl-2 ratio, which lead to inhibition of Cyt C release and following caspase-9 activation.

Mitochondrial dysfunction,oxidative stress and apoptotic induction in microglial BV-2 cells treated with sodium arsenate

The treatment of microglial BV-2 cells with sodium arsenate（As（V）：0.1-400 μmol/L — 48 hr）induces a dose-dependent response.The neurotoxic effects of high concentrations of As（V）（100,200 and 400 μmol/L） are characterized by increased levels of mitochondrial complexesⅠ,Ⅱ,and Ⅳ followed by increased superoxide anion generation.Moreover,As（V） triggers an apoptotic mode of cell death,demonstrated by an apoptotic SubG1 peak,associated with an alteration of plasma membrane integrity.There is also a decrease in transmembrane mitochondrial potential and mitochondrial adenosine triphosphate ATP.It is therefore tempting to speculate that As（V） triggers mitochondrial dysfunction,which may lead to defective oxidative phosphorylation subsequently causing mitochondrial oxidative damage,which in turn induces an apoptotic mode of cell death.

Sheng-Mai-San attenuates contractile dysfunction and structural damage induced by chronic intermittent hypoxia in mice

Sheng-Mai-San(SMS), a well-known Chinese medicinal plant formula, is widely used for the treatment of cardiac diseases characterized by deficiency of Qi and Yin syndrome. A mouse chronic intermittent hypoxia(CIH) model was established to mimic the primary clinical features of deficiency of Qi and Yin syndrome. Mice experienced CIH for 28 days(nadir 7% to peak 8% oxygen, 20 min per day), resulting in left ventricle(LV) dysfunction and structure abnormalities. After administration of SMS(0.55, 1.1, and 5.5 g·kg-1·d-1) for four weeks, improved cardiac function was observed, as indicated by the increase in the ejection fraction from the LV on echocardiography. SMS also preserved the structural integrity of the LV against eccentric hypotrophy, tissue vacuolization, and mitochondrial injury as measured by histology, electron microscopy, and ultrasound assessments. Mechanistically, the antioxidant effects of SMS were demonstrated; SMS was able to suppress mitochondrial apoptosis as indicated by the reduction of several pro-apoptotic factors(Bax, cytochrome c, and cleaved caspase-3) and up-regulation of the anti-apoptosis factor Bcl-2. In conclusion, these results demonstrate that SMS treatment can protect the structure and function of the LV and that the protective effects of this formula are associated with the regulation of the mitochondrial apoptosis pathway.