Life and death partners: apoptosis, autophagy and the cross-talk between them. Cell Death Differ. 2009;16:966-975. [PMID: 19325568 DOI: 10.1038/cdd.2009.33]

Increased autophagy/mitophagy levels in primary tumours of patients with pancreatic neuroendocrine neoplasms

BACKGROUND/AIMS

We assessed the levels of autophagy and mitophagy, that are linked to cancer development and drug resistance, in well differentiated pancreatic neuroendocrine neoplasms (PanNENs) and correlated them with clinico-pathological parameters.

METHODS

Fluorescent immunostaining for the autophagy markers LC3Β and p62/or LAMP1 was performed on 22 PanNENs and 11 controls of normal pancreatic tissues and validated through Western blotting. Autophagy quantitative scoring was generated for LC3B-positive puncta and analysed in relation to clinico-pathological parameters. TOMM20/LC3B qualitative assessment of mitophagy levels was undertaken by fluorescent immunostaining. The presence of autophagy/mitophagy was validated by transmission electron microscopy.

RESULTS

Autophagy levels (LC3B-positive puncta/cell) were discriminative for normal vs. NEN pancreatic tissue (p = 0.007). A significant association was observed between autophagy levels and tumour grade (Ki67 < 3% vs. Ki67 ≥ 3%; p = 0.021), but not functionality (p = 0.266) size (cut-off of 20 mm; p = 0.808), local invasion (p = 0.481), lymph node- (p = 0.849) and distant metastases (p = 0.699). Qualitative assessment of TOMM20/LC3B demonstrated strong mitophagy levels in PanNENs by fluorescent immunostaining as compared with normal tissue. Transmission electron microscopy revealed enhanced autophagy and mitophagy in PanNEN tissue. Response to molecular targeted therapies in metastatic cases (n = 4) did not reveal any patterns of association to autophagy levels.

CONCLUSIONS

Increased autophagy levels are present in primary tumours of patients with PanNENs and are partially attributed to upregulated mitophagy. Grade was the only clinico-pathological parameter associated with autophagy scores.

ADAM12 silencing promotes cellular apoptosis by activating autophagy in choriocarcinoma cells

ADAM metallopeptidase domain 12 (ADAM12) has been demonstrated to mediate cell proliferation and apoptosis resistance in several types of cancer cells. However, the effect of ADAM12 silencing on the proliferation and apoptosis of choriocarcinoma cells remains unknown. The present study revealed that ADAM12 silencing significantly inhibited cellular activity and proliferation in the human choriocarcinoma JEG3 cell line and increased the rate of apoptosis. In addition, ADAM12 silencing significantly increased the expression levels of the autophagy proteins microtubule-associated protein-light-chain 3 (LC3B) and autophagy related 5 (ATG5) and the fluorescence density of LC3B in JEG-3 cells. However, the suppression of autophagy by 3-methyladenine could block ADAM12 silencing-induced cellular apoptosis. ADAM12 silencing reduced the levels of the inflammatory factors interleukin-1β, interferon-γ and TNF-α, and inactivated nuclear p65-NF-κB and p-mTOR in JEG-3 cells. The downregulation of p-mTOR expression by ADAM12 silencing was rescued in 3-methyladenine-treated JEG-3 cells, indicating that mTOR might participate in the autophagy-mediated pro-apoptotic effect of ADAM12 silencing. In conclusion, ADAM12 silencing promoted cellular apoptosis in human choriocarcinoma JEG3 cells, which might be associated with autophagy and the mTOR response. These findings indicate that ADAM12 silencing might be a potential novel therapeutic target for choriocarcinoma.

Gonadotrophins modulate cell death-related genes expression in human endometrium

Background Gonadotrophins exert their functions by binding follicle-stimulating hormone receptor (FSHR) or luteinizing hormone and human chorionic gonadotropin receptor (LHCGR) present on endometrium. Within ovaries, FSH induces autophagy and apoptosis of granulosa cells leading to atresia of non-growing follicles, whereas hCG and LH have anti-apoptotic functions. Endometrial cells express functioning gonadotrophin receptors. The objective of this study was to analyze the effect of gonadotrophins on physiology and endometrial cells survival. Materials and methods Collected endometria were incubated for 48 or 72 h with 100 ng/mL of recombinant human FSH (rhFSH), recombinant human LH (rhLH) or highly purified hCG (HPhCG) alone or combined. Controls omitted gonadotrophins. The effect of gonadotrophins on cytochrome P450 family 11 subfamily A polypeptide 1 (CYP11A1), hypoxia inducible factor 1α (HIF1A), and cell-death-related genes expression was evaluated by reverse transcription quantitative polymerase chain reaction (RT-qPCR). Immunohistochemistry for microtubule-associated proteins 1A/1B light chain 3B (MAP1LC3B) and apoptotic protease activating factor 1 (APAF-1) was performed. Results Gonadotrophins are able to modulate the endometrial cells survival. FSH induced autophagy and apoptosis by increasing the relative expression of MAP1LC3B and FAS receptor. In FSH-treated samples, expression of apoptosis marker APAF-1 was detected and co-localized on autophagic cells. hCG and LH does not modulate the expression of cell-death-related genes while the up-regulation of pro-proliferative epiregulin gene was observed. When combined with FSH, hCG and LH prevent autophagy and apoptosis FSH-induced. Conclusions Different gonadotrophins specifically affect endometrial cells viability differently: FSH promotes autophagy and apoptosis while LH and hCG alone or combined with rhFSH does not.

Slit2/Robo1 Mitigates DSS-induced Ulcerative Colitis by Activating Autophagy in Intestinal Stem Cell

Ulcerative colitis (UC) is a recurrent intestinal inflammatory disease. Slit2, a secreted protein, interacts with its receptor Robo1 to regulate the differentiation of intestinal stem cells and participate in inflammation and tumor development. However, whether Slit2/Robo1involved in the pathogenesis of UC is not known. We investigated Slit2/Robo1-mediated UC using a dextran sodium sulfate (DSS)-induced model. Eight-week-old male Slit2-Tg (Slit2 transgene) mice, Robo1/2+/- (Robo1+/- Robo2+/-) mice, and their WT littermates were allocated into two groups: (I) control group (n=10), of mice fed a normal diet and tap water and (II) DSS group (n=10), of mice fed a normal diet and drinking water with 2% DSS for 7 days. Colon tissues were collected and analyzed by qPCR, immunohistochemistry, western blot, and immunofluorescence. Slit2-Tg DSS mice showed less body weight loss, less blood in the stool, and less viscous stool compared to those of WTSlit DSS mice. Robo1/2+/- DSS mice displayed a heavier degree of blood in the stool and a more apparent viscosity of the stool compared to those of WTRobo1/2 DSS mice. Slit2 overexpression maintained Lgr5+ stem cell proliferation in the crypt after DSS treatment, significantly increased the LC3II/I ratio, and slightly stimulated p62 expression in the crypt compared to those of DSS-induced WTSlit mice. Robo1/2 partial knockout reduced the number of Lgr5+ stem cells, decreased the LC3II/I ratio, and markedly increased p62 expression in the crypt compare to those of DSS-treated WTRobo1/2 mice. Our findings suggest that Slit2/Robo1 mediates DSS-induced UC probably by activating the autophagy of Lgr5+ stem cells.

Downregulation of c‑FLIP and upregulation of DR‑5 by cantharidin sensitizes TRAIL‑mediated apoptosis in prostate cancer cells via autophagy flux

Tumor necrosis factor (TNF)-related apop-tosis-inducing ligand (TRAIL), a type II transmembrane protein, is a part of the TNF superfamily of cytokines. Cantharidin, a type of terpenoid, is extracted from the blister beetles (Mylabris genus) used in Traditional Chinese Medicine. Cantharidin elicits antibiotic, antiviral and antitumor effects, and can affect the immune response. The present study demonstrated that a cantharidin and TRAIL combination treatment regimen elicited a synergistic outcome in TRAIL-resistant DU145 cells. Notably, it was also identified that cantharidin treatment initiated the downregulation of cellular FLICE-like inhibitory protein (c-FLIP) and upregulation of death receptor 5 (DR-5), and sensitized cells to TRAIL-mediated apoptosis by initiating autophagy flux. In addition, cantharidin treatment increased lipid-modified microtubule-associated proteins 1A/1B light chain 3B expression and significantly attenuated sequestosome 1 expression. Attenuation of autophagy flux by a specific inhibitor such as chloroquine and genetic modification using ATG5 small interfering RNA abrogated the cantharidin-mediated TRAIL-induced apoptosis. Overall, the results of the present study revealed that cantharidin effectively sensitized cells to TRAIL-mediated apoptosis and its effects are likely to be mediated by autophagy, the downregulation of c-FLIP and the upregulation of DR-5. They also suggested that the combination of cantharidin and TRAIL may be a successful therapeutic strategy for TRAIL-resistant prostate cancer.

Mechanistic Study of Triazole Based Aminodiol Derivatives in Leukemic Cells-Crosstalk between Mitochondrial Stress-Involved Apoptosis and Autophagy

Various derivatives that mimic ceramide structures by introducing a triazole to connect the aminodiol moiety and long alkyl chain have been synthesized and screened for their anti-leukemia activity. SPS8 stood out among the derivatives, showing cytotoxic selectivity between leukemic cell lines and human peripheral blood mononuclear cells (about ten times). DAPI nuclear staining and H&E staining revealed DNA fragmentation under the action of SPS8. SPS8 induced an increase in intracellular Ca²⁺ levels and mitochondrial stress in HL-60 cells identified by the loss of mitochondrial membrane potential, transmission electron microscopy (TEM) examination, and altered expressions of Bcl-2 family proteins. SPS8 also induced autophagy through the detection of Atg5, beclin-1, and LC3 II protein expression, as well as TEM examination. Chloroquine, an autophagy inhibitor, promoted SPS8-induced apoptosis, suggesting the cytoprotective role of autophagy in hindering SPS8 from apoptosis. Furthermore, SPS8 was shown to alter the expressions of a variety of genes using a microarray analysis and volcano plot filtering. A further cellular signaling pathways analysis suggested that SPS8 induced several cellular processes in HL-60, including the sterol biosynthesis process and cholesterol biosynthesis process, and inhibited some cellular pathways, in which STAT3 was the most critical nuclear factor. Further identification revealed that SPS8 inhibited the phosphorylation of STAT3, representing the loss of cytoprotective activity. In conclusion, the data suggest that SPS8 induces both apoptosis and autophagy in leukemic cells, in which autophagy plays a cytoprotective role in impeding apoptosis. Moreover, the inhibition of STAT3 phosphorylation may support SPS8-induced anti-leukemic activity.

Autophagy Induced by Simian Retrovirus Infection Controls Viral Replication and Apoptosis of Jurkat T Lymphocytes

Autophagy and apoptosis are two important evolutionarily conserved host defense mechanisms against viral invasion and pathogenesis. However, the association between the two pathways during the viral infection of T lymphocytes remains to be elucidated. Simian type D retrovirus (SRV) is an etiological agent of fatal simian acquired immunodeficiency syndrome (SAIDS), which can display disease features that are similar to acquired immunodeficiency syndrome in humans. In this study, we demonstrate that infection with SRV-8, a newly isolated subtype of SRV, triggered both autophagic and apoptotic pathways in Jurkat T lymphocytes. Following infection with SRV-8, the autophagic proteins LC3 and p62/SQSTM1 interacted with procaspase-8, which might be responsible for the activation of the caspase-8/-3 cascade and apoptosis in SRV-8-infected Jurkat cells. Our findings indicate that autophagic responses to SRV infection of T lymphocytes promote the apoptosis of T lymphocytes, which, in turn, might be a potential pathogenetic mechanism for the loss of T lymphocytes during SRV infection.

High cholesterol induces apoptosis and autophagy through the ROS-activated AKT/FOXO1 pathway in tendon-derived stem cells

BACKGROUND

Hypercholesterolemia increases the risk of tendon pain and tendon rupture. Tendon-derived stem cells (TDSCs) play a vital role in the development of tendinopathy. Our previous research found that high cholesterol inhibits tendon-related gene expression in TDSCs. Whether high cholesterol has other biological effects on TDSCs remains unknown.

METHODS

TDSCs isolated from female SD rats were exposed to 10 mg/dL cholesterol for 24 h. Then, cell apoptosis was assessed using flow cytometry and fluorescence microscope. RFP-GFP-LC3 adenovirus transfection was used for measuring autophagy. Signaling transduction was measured by immunofluorescence and immunoblotting. In addition, Achilles tendons from ApoE -/- mice fed with a high-fat diet were histologically assessed using HE staining and immunohistochemistry.

RESULTS

In this work, we verified that 10 mg/dL cholesterol suppressed cell proliferation and migration and induced G0/G1 phase arrest. Additionally, cholesterol induced apoptosis and autophagy simultaneously in TDSCs. Apoptosis induction was related to increased expression of cleaved caspase-3 and BAX and decreased expression of Bcl-xL. The occurrence of autophagic flux and accumulation of LC3-II demonstrated the induction of autophagy by cholesterol. Compared with the effects of cholesterol treatment alone, the autophagy inhibitor 3-methyladenine (3-MA) enhanced apoptosis, while the apoptosis inhibitor Z-VAD-FMK diminished cholesterol-induced autophagy. Moreover, cholesterol triggered reactive oxygen species (ROS) generation and activated the AKT/FOXO1 pathway, while the ROS scavenger NAC blocked cholesterol-induced activation of the AKT/FOXO1 pathway. NAC and the FOXO1 inhibitor AS1842856 rescued the apoptosis and autophagy induced by cholesterol. Finally, high cholesterol elevated the expression of cleaved caspase-3, Bax, LC3-II, and FOXO1 in vivo.

CONCLUSION

The present study indicated that high cholesterol induced apoptosis and autophagy through ROS-activated AKT/FOXO1 signaling in TDSCs, providing new insights into the mechanism of hypercholesterolemia-induced tendinopathy. High cholesterol induces apoptosis and autophagy through the ROS-activated AKT/FOXO1 pathway in tendon-derived stem cells.

Origanum majorana Essential Oil Triggers p38 MAPK-Mediated Protective Autophagy, Apoptosis, and Caspase-Dependent Cleavage of P70S6K in Colorectal Cancer Cells

Colorectal cancer (CRC) is the third most common type of cancer in terms of incidence and mortality worldwide. Here we have investigated the anti-colon cancer potential of Origanum majorana essential oil (OMEO) and its underlying mechanisms of action. We showed that OMEO significantly inhibited the cellular viability and colony growth of human HT-29 colorectal cancer cells. OMEO induced protective autophagy, associated with downregulation of the mTOR/p70S6K pathway, and activated caspase-8 and caspase-9-dependent apoptosis. Blockade of autophagy with 3-methyladenine (3-MA) and chloroquine (CQ), two autophagy inhibitors, potentiated the OMEO-induced apoptotic cell death. Inversely, inhibition of apoptosis with the pan-caspase inhibitor, Z-VAD-FMK, significantly reduced cell death, suggesting that apoptosis represents the main mechanism of OMEO-induced cell death. Mechanistically, we found that OMEO induces protective autophagy and apoptotic cells death via the activation of the p38 MAPK signaling pathway. Pharmacological inhibition of p38 MAPK by the p38 inhibitors SB 202190 and SB 203580 not only significantly decreased apoptotic cell death, but also reduced the autophagy level in OMEO treated HT-29 cells. Strikingly, we found that OMEO also induces p38 MAPK-mediated caspase-dependent cleavage of p70S6K, a protein reported to be overexpressed in colon cancer and associated with drug resistance. Our findings suggest that OMEO inhibits colon cancer through p38 MAPK-mediated protective autophagy and apoptosis associated with caspase-dependent cleavage of p70S6K. To the best of our knowledge, this study is the first to report on the implications of the p38 MAPK signaling pathway in targeting p70S6K to caspase cleavage.

Cordyceps sinensis polysaccharide inhibits colon cancer cells growth by inducing apoptosis and autophagy flux blockage via mTOR signaling

Cordyceps sinensis is thought to have anti-cancer effects, but its mechanisms remain elusive. In this study, we aimed to investigate the anti-cancer effect of Cordyceps sinensis polysaccharide (CSP) on human colon cancer cell line (HCT116) and its mechanism. Results indicated that CSP significantly inhibited the proliferation of HCT116 cells, increased autophagy and apoptosis, while blocked autophagy flux and lysosome formation. Further experiments showed that CSP decreased the expression of PI3K and phosphorylation level of AKT and mTOR, increased the expression of AMPKa and phosphorylation level of ULK1. In addition, repression of CSP-induced autophagy by bafilomycin (autophagy inhibitor) enhanced apoptosis and cell death of HCT116 cells. Hence, our findings suggested that CSP inhibited the proliferation of HCT116 cells by inducing apoptosis and autophagy flux blockage, which might be achieved through PI3K-AKT-mTOR and AMPK-mTOR-ULK1 signaling. CSP may be a potential therapeutic agent for colon cancer.

Modulation of autophagy for neuroprotection and functional recovery in traumatic spinal cord injury

Spinal cord injury (SCI) is a serious central nervous system trauma that leads to loss of motor and sensory functions in the SCI patients. One of the cell death mechanisms is autophagy, which is 'self-eating' of the damaged and misfolded proteins and nucleic acids, damaged mitochondria, and other impaired organelles for recycling of cellular building blocks. Autophagy is different from all other cell death mechanisms in one important aspect that it gives the cells an opportunity to survive or demise depending on the circumstances. Autophagy is a therapeutic target for alleviation of pathogenesis in traumatic SCI. However, functions of autophagy in traumatic SCI remain controversial. Spatial and temporal patterns of activation of autophagy after traumatic SCI have been reported to be contradictory. Formation of autophagosomes following therapeutic activation or inhibition of autophagy flux is ambiguous in traumatic SCI studies. Both beneficial and harmful outcomes due to enhancement autophagy have been reported in traumatic SCI studies in preclinical models. Only further studies will make it clear whether therapeutic activation or inhibition of autophagy is beneficial in overall outcomes in preclinical models of traumatic SCI. Therapeutic enhancement of autophagy flux may digest the damaged components of the central nervous system cells for recycling and thereby facilitating functional recovery. Many studies demonstrated activation of autophagy flux and inhibition of apoptosis for neuroprotective effects in traumatic SCI. Therapeutic induction of autophagy in traumatic SCI promotes axonal regeneration, supporting another beneficial role of autophagy in traumatic SCI. In contrast, some other studies demonstrated that disruption of autophagy flux in traumatic SCI strongly correlated with neuronal death at remote location and impaired functional recovery. This article describes our current understanding of roles of autophagy in acute and chronic traumatic SCI, cross-talk between autophagy and apoptosis, therapeutic activation or inhibition of autophagy for promoting functional recovery, and future of autophagy in traumatic SCI.

Montelukast ameliorates Concanavalin A-induced autoimmune hepatitis in mice via inhibiting TNF-α/JNK signaling pathway

BACKGROUND

Concanavalin A (ConA) is a well-established model to induce autoimmune hepatitis (AIH) in mice which mimics pathological alterations that occur in human. The pathogenesis of ConA-induced AIH involves many signaling pathways. Montelukast is a leukotriene receptor antagonist that is mainly used in the management of asthma. The antioxidant, anti-inflammatory and anti-apoptotic effects of montelukast have been reported in previous studies. Lately, montelukast has been documented to confer protection against various inflammatory diseases. Up to date, no study has explored the effect of montelukast on AIH induced by ConA.

AIM AND METHOD

This study aims to detect the protective effects of montelukast (10 mg/kg) on ConA (20 mg/kg)- induced AIH in mice and to demonstrate its hepatoprotective mechanisms. Hepatic function, histological changes, oxidative stress, inflammation, autophagy, and apoptotic markers were investigated.

RESULTS

Hepatic function and histological data revealed that treatment with montelukast significantly attenuated ConA-induced hepatic damage. Montelukast significantly reduced JNK level and NFκB p65 expression, and inhibited proinflammatory cytokines (TNF-α and IL-6) as well as oxidative stress (MDA, NO, and GSH). Moreover, inflammatory cells (CD4+ infiltration and the levels of apoptotic markers (Bax and caspase-3) besides autophagy biomarkers (Beclin1 and LC3) were reduced.

CONCLUSION

Our results suggest that montelukast could be a potential therapeutic drug against the ConA-induced AIH through its anti-oxidant, anti-inflammatory, anti- autophagy as well as anti-apoptotic properties.

Bruceine D induces lung cancer cell apoptosis and autophagy via the ROS/MAPK signaling pathway in vitro and in vivo

Worldwide, lung cancer remains a leading cause of cancer mortality. Bruceine D (BD) has been shown to induce pancreatic cancer cell death via several different mechanisms. In this study, we demonstrated that BD inhibited lung cancer cell proliferation. Apoptosis and autophagy were the most important mechanisms involved in BD-induced lung cancer cell death, and complete autophagic flux was observed in A549 and NCI-H292 cells. In addition, BD significantly improved intracellular reactive oxygen species (ROS) levels. BD-mediated cell apoptosis and autophagy were almost inhibited in cells pretreated with N-acetylcysteine (NAC), an ROS scavenger. Furthermore, MAPK signaling pathway activation contributed to BD-induced cell proliferation inhibition and NAC could eliminate p-ERK and p-JNK upregulation. Finally, an in vivo study indicated that BD inhibited the growth of lung cancer xenografts. Overall, BD is a promising candidate for the treatment of lung cancer owing to its multiple mechanisms and low toxicity.

Nobiletin Triggers Reactive Oxygen Species-Mediated Pyroptosis through Regulating Autophagy in Ovarian Cancer Cells

Ovarian cancer is one of the most serious female malignancies worldwide. Despite intensive efforts being made to overcome ovarian cancer, there still remain limited optional treatments for this disease. Nobiletin, a prospective food-derived phytochemical extracted from citrus fruits, has recently been reported to suppress ovarian cancer cells, but the role of pyroptosis in ovarian carcinoma with nobiletin still remains unknown. In this study, we aim to explore the effect of nobiletin on ovarian carcinoma and further expound the underlying mechanisms of nobiletin-induced ovarian cancer cell death. Our results showed that nobiletin could significantly inhibit cell proliferation, induce DNA damage, and also lead to apoptosis by increasing the cleaved poly (ADP-ribose) polymerase (PARP) level of human ovarian cancer cells (HOCCs) in a dose-dependent manner. Moreover, we revealed that nobiletin decreased mitochondrial membrane potential and induced reactive oxygen species (ROS) generation and autophagy of HOCCs, contributing to gasdermin D-/gasdermin E-mediated pyroptosis. Taken together, nobiletin as a functional food ingredient represents a promising new anti-ovarian cancer candidate that could induce apoptosis and trigger ROS-mediated pyroptosis through regulating autophagy in ovarian cancer cells.

Potential implications of hydrogen peroxide in the pathogenesis and therapeutic strategies of gliomas

Glioma is the most common type of primary brain tumor, and it has a high mortality rate. Currently, there are only a few therapeutic approaches for gliomas, and their effects are unsatisfactory. Therefore, uncovering the pathogenesis and exploring more therapeutic strategies for the treatment of gliomas are urgently needed to overcome the ongoing challenges. Cellular redox imbalance has been shown to be associated with the initiation and progression of gliomas. Among reactive oxygen species (ROS), hydrogen peroxide (H₂O₂) is considered the most suitable for redox signaling and is a potential candidate as a key molecule that determines the fate of cancer cells. In this review, we discuss the potential cellular and molecular roles of H₂O₂ in gliomagenesis and explore the potential implications of H₂O₂ in radiotherapy and chemotherapy and in the ongoing challenges of current glioma treatment. Moreover, we evaluate H₂O₂ as a potential redox sensor and potential driver molecule of nanocatalytic therapeutic strategies for glioma treatment.

The Preparation of Ginsenoside Rg5, Its Antitumor Activity against Breast Cancer Cells and Its Targeting of PI3K

Ginsenosides have been reported to possess various pharmacological effects, including anticancer effects. Nevertheless, there are few reports about the antitumor activity and mechanisms of ginsenoside Rg5 against breast cancer cells. In the present study, the major ginsenoside Rb1 was transformed into the rare ginsenoside Rg5 through enzymatic bioconversion and successive acid-assisted high temperature and pressure processing. Ginsenosides Rb1, Rg3, and Rg5 were investigated for their antitumor effects against five human cancer cell lines via the MTT assay. Among them, Rg5 exhibited the greatest cytotoxicity against breast cancer. Moreover, Rg5 remarkably suppressed breast cancer cell proliferation through mitochondria-mediated apoptosis and autophagic cell death. LC3B-GFP/Lysotracker and mRFP-EGFP-LC3B were utilized to show that Rg5 induced autophagosome-lysosome fusion. Western blot assays further illustrated that Rg5 decreased the phosphorylation levels of PI3K, Akt, mTOR, and Bad and suppressed the PI3K/Akt signaling pathway in breast cancer. Moreover, Rg5-induced apoptosis and autophagy could be dramatically strengthened by the PI3K/Akt inhibitor LY294002. Finally, a molecular docking study demonstrated that Rg5 could bind to the active pocket of PI3K. Collectively, our results revealed that Rg5 could be a potential therapeutic agent for breast cancer treatment.

Melatonin protects the mouse testis against heat-induced damage

Spermatogenesis, an intricate process occurring in the testis, is responsible for ongoing production of spermatozoa and thus the cornerstone of lifelong male fertility. In the testis, spermatogenesis occurs optimally at a temperature 2–4°C lower than that of the core body. Increased scrotal temperature generates testicular heat stress and later causes testicular atrophy and spermatogenic arrest, resulting in a lower sperm yield and therefore impaired male fertility. Melatonin (N-acetyl-5-methoxytryptamine), a small neuro-hormone synthesized and secreted by the pineal gland and the testis, is widely known as a potent free-radical scavenger; it has been reported that melatonin protects the testis against inflammation and reactive oxygen species generation thereby playing anti-inflammatory, -oxidative and -apoptotic roles in the testis. Nevertheless, the role of melatonin in the testicular response to heat stress has not been studied. Here, by employing a mouse model of testicular hyperthermia, we systematically investigated the testicular response to heat stress as well as the occurrence of autophagy, apoptosis and oxidative stress in the testis. Importantly, we found that pre-treatment with melatonin attenuated heat-induced apoptosis and oxidative stress in the testis. Also, post-treatment with melatonin promoted recovery of the testes from heat-induced damage, probably by maintaining the integrity of the Sertoli cell tight-junction. Thus, we for the first time provide the proof of concept that melatonin can protect the testis against heat-induced damage, supporting the potential future use of melatonin as a therapeutic drug in men for sub/infertility incurred by various testicular hyperthermia factors.

Selective Intratumoral Drug Release and Simultaneous Inhibition of Oxidative Stress by a Highly Reductive Nanosystem and Its Application as an Anti-tumor Agent

Excessive oxidative stress is always associated with the serious side effects of chemotherapy. In the current study, we developed a vitamin E based strongly reductive nanosystem to increase the loading efficiency of docetaxel (DTX, DTX-VNS), reduce its side toxicity and enhance the antitumor effect. Methods: We used Förster Resonance Energy Transfer (FRET) to reveal the in vivo and in vitro fate of DTX-VNS over time. All FRET images were observed using the Maestro imaging system (CRI, Inc., Woburn, MA) and Fluo-View software (Olympus LX83-FV3000). Results: Through FRET analyzing, we found that our nanosystem showed a selective rapider release of drugs in tumors compared to normal organs due to the higher levels of ROS in tumor cells than normal cells, and the accumulation of DTX at tumor sites in the DTX-VNS group was also notably more than that in the Taxotere group after 24 h injection. Meanwhile, DTX-VNS had a prominently stronger anti-tumor effect in various models than Taxotere, and had a synergistic effect of immunotherapy. Conclusions: Our work presented a useful reference for clinical exploration of the in vivo behavior of nanocarriers (DTX-VNS), inhibition oxidative stress and selective release of drugs at tumor sites, thus reducing the side effects and enhancing the anti-tumor effects.

Genipin increases oxaliplatin-induced cell death through autophagy in gastric cancer

Oxaliplatin is used for treatment in combination with many drugs. However, the survival rate is still low due to side effects and drug resistance. Therefore, the combination with natural products was required for increasing efficacy and reducing side effects. Genipin, a natural product derived from the Gardenia jasminoides, associated with anti-angiogenic, anti-proliferative, hypertension, inflammatory, and the Hedgehog pathway. It is not known that genipin increases the therapeutic effect of oxaliplatin in gastric cancer. In this study, we found that genipin sensitizes oxaliplatin-induced apoptosis for the first time using colony forming assay, FACS analysis, and western blotting in gastric cancer. Additionally, genipin induced p53 expression in AGS, MKN45, and MKN28 cells. Also, genipin induced autophagy and LC3 expression. Knockdown of LC3 decreased cell death enhanced by the combination of oxaliplatin and genipin. In summary, we showed that genipin increases the oxaliplatin-induced cell death via p53-DRAM autophagy. Based on this, we suggest that genipin is a sensitizer of oxaliplatin.

Ubenimex induces autophagy inhibition and EMT suppression to overcome cisplatin resistance in GC cells by perturbing the CD13/EMP3/PI3K/AKT/NF-κB axis

Cisplatin (CDDP)-based chemotherapy is a standard treatment for gastric cancer (GC). However, chemoresistance is a major obstacle for CDDP application. Exploring underlying mechanisms of CDDP resistance development in GC and selecting an effective strategy to overcome CDDP resistance remain a challenge. Here, we demonstrate that a transmembrane ectoenzyme, CD13, endows GC patients with insensitivity to CDDP and predicts an undesirable prognosis in GC patients with CDDP treatment. Similarly, CD13 expression is positively related with CDDP resistance in GC cells. A CD13 inhibitor, Ubenimex, reverses CDDP resistance and renders GC cells sensitivity to CDDP, for which CD13 reduction is essential, and epithelial membrane protein 3 (EMP3) is a putative target downstream of CD13. Furthermore, Ubenimex decreases EMP3 expression by boosting its CpG island hypermethylation for which CD13 down-regulation is required. In addition, EMP3 is a presumptive modifier by which CD13 exerts functions in the phosphoinositol 3-kinase/protein kinase B (PI3K/AKT) pathway. Ubenimex inhibits the activation of the CD13/EMP3/PI3K/AKT/NF-κB pathway to overcome CDDP resistance in GC cells by suppressing autophagy and epithelial-mesenchymal transition (EMT). Therefore, CD13 is a potential indicator of CDDP resistance formation, and Ubenimex may serve as a potent candidate for reversing CDDP resistance in GC.

Effect of autophagy induction and cathepsin B inhibition on developmental competence of poor quality bovine oocytes

The present study investigated the effect of autophagy induction and cathepsin B (CTSB) inhibition on developmental competence of poor quality oocytes. Bovine cumulus oocyte complexes (COCs) were classified as good or poor according to their morphology. Autophagy activity was detected in good and poor germinal vesicle (GV) oocytes. Then E-64, a CTSB inhibitor, rapamycin (Rapa), an autophagy inducer, and combined administration was achieved during in vitro maturation (IVM) of poor quality COCs followed by detection of autophagy activity. In the next experiment, E-64, Rapa, and E64 + Rapa, were added during IVM to good and poor quality COCs followed by in vitro fertilization and culture for 8 days to investigate whether inhibition of CTSB and/or induction of autophagy improve embryonic development and quality. Autophagy activity was significantly lower in poor quality GV oocytes than in good quality ones. E-64, Rapa and E-64 + Rapa treatment during IVM significantly increased autophagy activity in poor quality oocytes. Addition of Rapa in good quality COCs did not increase the blastocyst rate, whereas E-64 increased the blastocyst rate and total cell number (TCN) with decreasing TUNEL-positive cells. In contrast, Rapa treatment in poor quality COCs significantly increased the blastocyst rate and TCN with decreasing TUNEL-positive cells. These results indicate oocyte quality has different responses to intracellular autophagy induction and CTSB activity control by potential autophagy and catabolic status, however, synergetic effect of autophagy induction and CTSB inhibition can increase developmental competence of both good and poor quality COCs, especially rescue effect in poor quality COCs.

The effect of Yarrowia lipolytical-asparaginase on apoptosis induction and inhibition of growth in Burkitt's lymphoma Raji and acute lymphoblastic leukemia MOLT-4 cells

l-Asparaginase (l-asparagine amidohydrolase; E.C.3.5.1.1) as an anticancer agent is used to treat acute lymphocytic leukemia (ALL), Human Burkitt's lymphoma and non-Hodgkin's lymphoma. The commercial asparaginases are obtained from bacteria Erwinia chrysanthemi and Escherichia coli now which had many side effects. In this study, the effects of a novel l-asparaginase from yeast Yarrowia lipolytica was investigated on human ALL and Burkitt's lymphoma cell lines. The l-asparaginase causes metabolic stress, cytotoxicity, and apoptosis due to the arrest of the G0 cell cycle, the activation of caspase-3 and the modulation of mitochondrial membrane integrity. The RT-PCR analysis showed a significant increase in the pro-apoptosis genes such as Bax, Caspase-3, Caspase-8, Caspase-9 and p53 (P < 0.05) while the anti-apoptotic marker Bcl-2 was significantly decreased (P < 0.05). Furthermore, Y. lipolytical-asparaginase causes autophagy and increased ROS. The l-asparaginase has cytotoxic and anticancer effects higher than commercial asparaginase. In conclusion, Y. lipolytical-asparaginase shows interesting anticancer activity and it can be introduced as a new eukaryotic and therapeutic agent and strategy for ALL and Burkitt's lymphoma treatment after the in vivo and clinical experiments.

Multioside, an active ingredient from adonis amurensis, displays anti-cancer activity through autophagosome formation

BACKGROUND

Adonis amurensis Regel & Radde, commonly found in East Asia, has been traditionally used to treat cardiac insufficiency and edema. Although this plant extract has been shown to regulate cell growth and neovascularization, the anti-cancer mechanism of A. amurensis has not been fully investigated.

PURPOSE

In this study, we aimed to examine the anti-cancer activity of A. amurensis and identify its underlying mechanism.

METHODS

The growth of cancer cells was evaluated by MTT and hollow fiber assays. A cancer xenograft nude mouse model was used to assess the anti-cancer activities in vivo. Autophagic activity was measured by the detection of autophagosome formation and by performing a monodansylcadaverine (MDC) assay.

RESULT

A. amurensis extract showed potent anti-cancer activity both in vitro and in vivo. Importantly, the treatment of cancer cells with A. amurensis extract dramatically increased the formation of autophagosomes and was involved in the activation of multiple signaling components including AKT, ERK, and MAPK. Furthermore, we isolated an active ingredient, Multioside, which exhibited strong anti-cancer activity through autophagy.

CONCLUSION

A. amurensis displays anti-cancer activity that is mediated by the activation of autophagy, suggesting that A. amurensis could be a useful therapeutic anti-cancer agent.

T-cell-specific mTOR deletion in mice ameliorated CD4+ T-cell survival in lethal sepsis induced by severe invasive candidiasis

The mammalian target of rapamycin (mTOR) pathway can mediate T-cell survival; however, the role of this pathway in T-cell survival during fungal sepsis is unclear. Here, we investigated the role of the mTOR pathway in CD4+ T-cell survival in a mouse model of rapidly progressive lethal sepsis induced by severe invasive candidiasis and explored the possible mechanism. The decrease in CD4+ T-cell survival following fungal sepsis was ameliorated in mice with a T-cell-specific mTOR deletion, whereas it was exacerbated in mice with a T-cell-specific tuberous sclerosis complex (TSC)1 deletion. To explore the mechanism further, we measured expression of autophagy proteins light chain 3B and p62/sequestosome 1 in CD4+ T cells. Both proteins were increased in T-cell-specific mTOR knockout mice but lower in T-cell-specific TSC1 knockout mice. Transmission electron microscopy revealed that T-cell-specific mTOR knockout mice had more autophagosomes than wild-type mice following fungal sepsis. CD4+ T-cell mTOR knockout decreased CD4+ T-cell apoptosis in fungal sepsis. Most notably, the T-cell-specific mTOR deletion mice had an increased survival rate after fungal sepsis. These results suggest that the mTOR pathway plays a vital role in CD4+ T-cell survival during fungal sepsis, partly through the autophagy-apoptosis pathway.

Reduced expression of proteolipid protein 2 increases ER stress-induced apoptosis and autophagy in glioblastoma

Proteolipid protein 2 (PLP2) is an integral ion channel membrane protein of the endoplasmic reticulum. The protein has been shown to be highly expressed in many cancer types, but its importance in glioma progression is poorly understood. Using publicly available datasets (Rembrandt, TCGA and CGGA), we found that the expression of PLP2 was significantly higher in high‐grade gliomas than in low‐grade gliomas. We confirmed these results at the protein level through IHC staining of high‐grade (n = 56) and low‐grade glioma biopsies (n = 16). Kaplan‐Meier analysis demonstrated that increased PLP2 expression was associated with poorer patient survival. In functional experiments, siRNA and shRNA PLP2 knockdown induced ER stress and increased apoptosis and autophagy in U87 and U251 glioma cell lines. Inhibition of autophagy with chloroquine augmented apoptotic cell death in U87‐ and U251‐siPLP2 cells. Finally, intracranial xenografts derived from U87‐ and U251‐shPLP2 cells revealed that loss of PLP2 reduced glioma growth in vivo. Our results therefore indicate that increased PLP2 expression promotes GBM growth and that PLP2 represents a potential future therapeutic target.

Diverse autophagy and apoptosis in myeloid leukemia cells induced by 20(s)-GRh2 and blue LED irradiation

Autophagy is an important mechanism for cell death regulation. To improve the anticancer effect during the treatment of leukemia and promote the apoptosis of leukemic cells, it is important to define the relationship between autophagy and apoptosis. A key bioactive compound in traditional Chinese medicine, 20(s)-Ginsenoside (GRh2), demonstrated an advancement in leukemia treatment. Blue LED therapy (BL) is a physical treatment method that can induce leukemic cell death. In this study, we tested the effect of 20(s)-GRh2, BL, and their combination (BL-GRh2) on the activation of leukemic cell apoptosis and autophagy. Both treatments, whether used individually or simultaneously, induce apoptosis through the induction of reactive oxygen species (ROS), disrupted mitochondrial membrane potential (MMP) and regulated the expression of apoptosis-related genes and proteins. Furthermore, using western blotting to analyze the autophagy markers LC3B and P62, we detected the activation of autophagy. In cells treated with autophagy inhibitor 3-MA, both autophagy and apoptosis were inhibited, either by BL alone or by BL-GRh2. However, apoptosis in 20(s)-GRh2-treated cells was enhanced. In cells treated with apoptosis suppressor Z-VAD-FMK, autophagy was inhibited in the BL and BL-GRh2-treated cells, although it was enhanced in cells treated with 20(s)-GRh2 alone. Moreover, we observed a stronger induction of apoptosis by BL-GRh2 in myeloid leukemia cells. Our data indicate that autophagy induced by different factors can play diverse roles on the same cells. Our results also indicate that the combination of traditional Chinese medicine with physical therapy may be a new strategy for anti-cancer therapy.

Synergistic Autophagy Effect of miR-212-3p in Zoledronic Acid-Treated In Vitro and Orthotopic In Vivo Models and in Patient-Derived Osteosarcoma Cells

Osteosarcoma (OS) originates from osteoid bone tissues and is prone to metastasis, resulting in a high mortality rate. Although several treatments are available for OS, an effective cure does not exist for most patients with advanced OS. Zoledronic acid (ZOL) is a third-generation bisphosphonate that inhibits osteoclast-mediated bone resorption and has shown efficacy in treating bone metastases in patients with various types of solid tumors. Here, we sought to clarify the mechanisms through which ZOL inhibits OS cell proliferation. ZOL treatment inhibited OS cell proliferation, viability, and colony formation. Autophagy inhibition by RNA interference against Beclin-1 or ATG5 inhibited ZOL-induced OS cell death. ZOL induced autophagy by repressing the protein kinase B/mammalian target of rapamycin/p70S6 kinase pathway and extracellular signal-regulated kinase signaling-dependent autophagy in OS cell lines and patient-derived OS cells. Microarrays of miRNA showed that ZOL increased the levels of miR-212-3p, which is known to play an important role in autophagy, in OS in vitro and in vivo systems. Collectively, our data provided mechanistic insight into how increased miR-212-3p through ZOL treatment induces autophagy synergistically in OS cells, providing a preclinical rationale for conducting a broad-scale clinical evaluation of ZOL + miR-212-3p in treating OS.

Apoptosis, Autophagy, and Pyroptosis: Immune Escape Strategies for Persistent Infection and Pathogenesis of Classical Swine Fever Virus

Classical swine fever (CSF) is a severe acute infectious disease that results from classical swine fever virus (CSFV) infection, which leads to serious economic losses in the porcine industry worldwide. In recent years, numerous studies related to the immune escape mechanism of the persistent infection and pathogenesis of CSFV have been performed. Remarkably, several independent groups have reported that apoptosis, autophagy, and pyroptosis play a significant role in the occurrence and development of CSF, as well as in the immunological process. Apoptosis, autophagy, and pyroptosis are the fundamental biological processes that maintain normal homeostatic and metabolic function in eukaryotic organisms. In general, these three cellular biological processes are always understood as an immune defense response initiated by the organism after perceiving a pathogen infection. Nevertheless, several viruses, including CSFV and other common pathogens such as hepatitis C and influenza A, have evolved strategies for infection and replication using these three cellular biological process mechanisms. In this review, we summarize the known roles of apoptosis, autophagy, and pyroptosis in CSFV infection and how viruses manipulate these three cellular biological processes to evade the immune response.

Hippophae rhamnoides polysaccharides protect IPEC-J2 cells from LPS-induced inflammation, apoptosis and barrier dysfunction in vitro via inhibiting TLR4/NF-κB signaling pathway

Inflammatory response caused by early weaning stress in piglets is associated with various diseases. The Hippophae rhamnoides polysaccharide (HRP) exhibits anti-inflammatory activity and immunomodulatory properties. The mechanisms for the protective effects of HRP on barrier function, inflammatory damage and apoptosis in intestinal porcine epithelial cells (IPEC-J2) induced by the lipopolysaccharide (LPS) are unknown. In this study, we first demonstrated the cytotoxicity of HRP-induced IPEC-J2 cells by reducing cell viability. IPEC-J2 cells were treated with 0-800 μg/mL doses of HRP, and 0-600 μg/mL doses were used in further experiments. Upon exposure to LPS, the viability of IPEC-J2 cells, ROS production, immunoglobulin levels (immunoglobulin M (IgM), immunoglobulin A (IgA) and immunoglobulin G (IgG)) and tight junction protein level (zonula occludens-1 (ZO-1), occluding, claudin-1) decreased. Inflammatory factors (interleukin-1beta (IL-1β), interleukin-6 (IL-6), interleukin-8 (IL-8) and tumor necrosis factor-alpha (TNF-α)) and apoptosis (Bcl-2, Bax, caspase-3, caspase-8 and caspase-9) were increased. Cell morphology and internal structure were damaged in the LPS treatment. Pre-treating cells with HRP (0-600 μg/mL) reduced inflammatory factors levels, apoptosis rate, increased immunoglobulins, tight junction protein levels and relieved cell surface morphology damage. Pre-treatment with HRP also reduced the levels of the Toll-like receptor 4 (TLR4) and Myeloid differentiation factor 88 (MyD88) and inhibited the phosphorylated NF-κB factor-kappa B (NF-κB) in cells induced by LPS. These results show that pre-treatment with HRP protected against LPS-induced IPEC-J2 cell damage through its anti-inflammatory activity.

Autophagy as a consequence of seasonal functions of testis and epididymis in adult male European bison (Bison bonasus, Linnaeus 1758)

The European bison is still an animal endangered with extinction, so by learning factors that regulate its reproduction, we can contribute to the survival of this species. On the other hand, autophagy is a dynamic, lisosomal, and evolutionary conserved process which is essential for animal cell survival, homeostasis, and differentiation. This process was demonstrated in many species and in many organs; however, information on the metabolic course of autophagy in the male reproductive system in seasonally reproducing species is lacking. Therefore, in this study, we examined for the first time several autophagy-related factors (mTOR, ULK1, Atg13, PI3K, beclin1, beclin2, Atg14, Atg5, Atg16L, LC3) in testicular and epididymal tissues obtained from adult male individuals of the European bison. We compared the level of gene expression, protein synthesis, and localization of autophagy-related factors between June, September, and December (before, during, and after reproductive activity, respectively). We confirmed that the induction of autophagy was at the highest level in the period after reproductive activity, i.e., in December, when a significant increase in the gene and protein expression was observed for the majority of these factors, probably to ensure cellular protection. However, autophagy was also clearly marked in September, during the intense spermatogenesis, and this may indicate a great demand for autophagy-related proteins required for the normal development of reproductive cells. Obtained results seem to confirm that autophagy pathway, as a consequence of seasonal reproduction, may control the normal course of spermatogenesis in the male European bison.

Identification of chlorprothixene as a potential drug that induces apoptosis and autophagic cell death in acute myeloid leukemia cells

Although acute myeloid leukemia (AML) is a highly heterogeneous malignance, the common molecular mechanisms shared by different AML subtypes play critical roles in AML development. It is possible to identify new drugs that are effective for various AML subtypes based on the common molecular mechanisms. Therefore, we developed a hypothesis-driven bioinformatic drug screening framework by integrating multiple omics data. In this study, we identified that chlorprothixene, a dopamine receptor antagonist, could effectively inhibit growth of AML cells from different subtypes. RNA-seq analysis suggested that chlorprothixene perturbed a series of crucial biological processes such as cell cycle, apoptosis, and autophagy in AML cells. Further investigations indicated that chlorprothixene could induce both apoptosis and autophagy in AML cells, and apoptosis and autophagy could act as partners to induce cell death cooperatively. Remarkably, chlorprothixene was found to inhibit tumor growth and induce in situ leukemic cell apoptosis in the murine xenograft model. Furthermore, chlorprothixene treatment could reduce the level of oncofusion proteins PML-RARα and AML1-ETO, thus elevate the expression of apoptosis-related genes, and lead to AML cell death. Our results provided new insights for drug repositioning of AML therapy and confirmed that chlorprothixene might be a potential candidate for treatment of different subtypes of AML by reducing expression of oncofusion proteins. DATABASE: RNA-seq data are available in GEO database under the accession number GSE124316.

Hydroxyl Group Difference between Anthraquinone Derivatives Regulate Different Cell Death Pathways via Nucleo-Cytoplasmic Shuttling of p53

BACKGROUND

Despite a number of measures having been taken for cancer management, it is still the second leading cause of death worldwide. p53 is the protein principally being targeted for cancer treatment. Targeting p53 localization may be an effective strategy in chemotherapy as it controls major cell death pathways based on its cellular localization. Anthraquinones are bioactive compounds widely being considered as potential anticancer agents but their mechanism of action is yet to be explored. It has been shown that the number and position of hydroxyl groups within the different anthraquinones like Emodin and Chrysophanol reflects the number of intermolecular hydrogen bonds which affect its activity. Emodin contains an additional OH group at C-3, in comparison to Chrysophanol and may differentially regulate different cell death pathways in cancer cell.

OBJECTIVE

The present study was aimed to investigate the effect of two anthraquinones Emodin and Chrysophanol on induction of different cell death pathways in human lung cancer cells (A549 cell line) and whether single OH group difference between these compounds differentially regulate cell death pathways.

METHODS

The cytotoxic effect of Emodin and Chrysophanol was determined by the MTT assay. The expression of autophagy and apoptosis marker genes at mRNA and protein level after treatment was checked by the RT-PCR and Western Blot, respectively. For cellular localization of p53 after treatment, we performed immunofluorescence microscopy.

RESULTS

We observed that both compounds depicted a dose-dependent cytotoxic response in A549 cells which was in concurrence with the markers associated with oxidative stress such as an increase in ROS generation, decrease in MMP and DNA damage. We also observed that both compounds up-regulated the p53 expression where Emodin causes nuclear p53 localization, which leads to down-regulation in mTOR expression and induces autophagy while Chrysophanol inhibits p53 translocation into nucleus, up-regulates mTOR expression and inhibits autophagy.

CONCLUSION

From this study, it may be concluded that the structural difference of single hydroxyl group may switch the mechanism from one pathway to another which could be useful in the future to improve anticancer treatment and help in the development of new selective therapies.

Abundances of autophagy-related protein LC3B in granulosa cells, cumulus cells, and oocytes during atresia of pig antral follicles

In mammals, apoptosis has been accepted as the type of programmed cell death (PCD) that occurs in ovarian follicles undergoing atresia. Results of recent studies, however, indicate autophagy may be an alternative mechanism involved in follicle depletion through independent or tandem actions with apoptosis. Western blotting and immunofluorescence procedures were used in the present study to investigate the abundances of LC3B protein in freshly collected granulosa cells (GCs), cumulus cells (CCs), and oocytes to evaluate whether autophagy is an important process of antral follicle atresia in sexually mature sows. Furthermore, apoptosis was analyzed using annexin V and TUNEL assays in the same cellular cohorts to evaluate the correlation between the two processes. Immunostaining results indicate autophagy was induced in the majority of GCs, CCs, and oocytes from early and advanced stage atretic follicles. The quantitative results of western blot analysis indicate there is a progressive increase (P <  0.05) in abundance of autophagy-related protein (LC3B-II) in these cells compared with cells in non-atretic follicles. Furthermore, there is confirmation that apoptosis occurs in the GCs of atretic follicles, thus indicating that in pigs apoptosis and autophagy are processes in GCs that regulate PCD and as a consequence antral follicle depletion. There was a greater abundance of LC3B-II in CCs and oocytes of atretic follicles, while apoptosis was not detected. It, therefore, is suggested that in these cells the two processes function independently, with autophagy having a cytoprotective rather than PCD mechanism of action.

WX20120108, a novel IAP antagonist, induces tumor cell autophagy via activating ROS-FOXO pathway

Recently, inhibitor of apoptosis proteins (IAPs) and some IAP antagonists were found to regulate autophagy, but the underlying mechanisms remain unclear. WX20120108 is an analogue of GDC-0152 (a known IAP antagonist) and displays more potent anti-tumor and autophagy-regulating activity in tumor cells, we investigated the regulatory mechanisms underlying WX20120108-induced autophagy. Using molecular docking and fluorescence polarization anisotropy (FPA) competitive assay, we first demonstrated that WX20120108, acting as an IAP antagonist, bound to the XIAP-BIR3, XIAP BIR2-BIR3, cIAP1 BIR3, and cIAP2 BIR3 domains with high affinities. In six cancer cell lines, WX20120108 inhibited the cell proliferation with potencies two to ten-fold higher than that of GDC-0152. In HeLa and MDA-MB-231 cells, WX20120108 induced caspase-dependent apoptosis and activated TNFα-dependent extrinsic apoptosis. On the other hand, WX20120108 induced autophagy in HeLa and MDA-MB-231 cells in dose- and time-dependent manners. We revealed that WX20120108 selectively activated Foxo3, evidenced by Foxo3 nuclear translocation in both gene modified cell line and HeLa cells, as well as the upregulated expression of Foxo3-targeted genes (Bnip3, Pik3c3, Atg5, and Atg4b), which played a key role in autophagy initiation. WX20120108-induced autophagy was significantly suppressed when Foxo3 gene was silenced. WX20120108 dose-dependently increased the generation of reactive oxygen species (ROS) in HeLa cells, and WX20120108-induced Foxo3 activation was completely blocked in the presence of catalase, a known ROS scavenger. However, WX20120108-induced ROS generation was not affected by cIAP1/2 or XIAP gene silencing. In conclusion, WX20120108-induced autophagy relies on activating ROS-Foxo3 pathway, which is independent of IAPs. This finding provides a new insight into the mechanism of IAP antagonist-mediated regulation of autophagy.

RCE‑4, a potential anti‑cervical cancer drug isolated from Reineckia carnea, induces autophagy via the dual blockade of PI3K and ERK pathways in cervical cancer CaSki cells

The steroidal saponin RCE‑4 (1β, 3β, 5β, 25S)‑spirostan‑1, 3‑diol 1‑[α‑L‑rhamnopyranosyl‑(1→2)‑β‑D‑xylopyranoside], isolated from Reineckia carnea, exerts significant anti‑cervical cancer activity by inducing apoptosis. The potential effect of RCE‑4 on proliferation inhibition and autophagy induction has rarely been studied. Therefore, the focus of the present study was to investigate the effects of RCE‑4 on proliferation, and to elucidate the detailed mechanisms involved in autophagy induction in cervical cancer cells. CaSki cells were treated with RCE‑4 or/and autophagy inhibitors, and the effect of RCE‑4 on cellular proliferation was assessed by MTT assay. The pro‑autophagic properties of RCE‑4 were subsequently confirmed using monomeric red fluorescent protein‑green fluorescent protein‑microtubule‑associated proteins 1A/1B light chain 3B (LC3) adenoviruses and CYTO‑ID autophagy assays, and by assessing the accumulation of lipid‑modified LC3 (LC3II). The mechanisms of RCE‑4‑induced autophagy were investigated by western blot analysis. The results demonstrated that inhibiting autophagy significantly promoted RCE‑4‑induced cell death, indicating that autophagy served a protective role following RCE‑4 treatment. In addition, RCE‑4‑induced autophagy was reflected by increased expression levels of the serine/threonine‑protein kinase ULK1, phosphorylated (p)‑ULK1, p‑Beclin‑1 and LC3II, the formation of autophagosomes and autolysosomes, and sequestosome 1 (p62) degradation. Subsequent analysis indicated that RCE‑4 activated the AMP‑activated protein kinase (AMPK) pathway by upregulating AMPK and p‑AMPK, and also inhibited the PI3K and extracellular signal‑regulated kinase (ERK) signaling pathways by downregulating p‑PI3K, p‑Akt, p‑mTOR, Ras, c‑Raf, p‑c‑Raf, dual specificity mitogen‑activated protein kinase kinase (MEK)1/2, p‑MEK1/2 and p‑Erk1/2. Additionally, with increased treatment times RCE‑4 may impair lysosomal cathepsin activity and inhibit autophagy flux by suppressing the expression of AMPK, p‑AMPK, ULK1, p‑ULK1 and p‑Beclin‑1, and upregulating that of p62. These results indicated that the dual RCE‑4‑induced inhibition of the PI3K and ERK pathways may result in a more significant anti‑tumor effect and prevent chemoresistance, compared with the inhibition of either single pathway; furthermore, dual blockade of PI3K and ERK, and the AMPK pathway may be involved in the regulation of autophagy caused by RCE‑4. Taken together, RCE‑4 induced autophagy to protect cancer cells against apoptosis, but AMPK‑mediated autophagy was inhibited in the later stages of RCE‑4 treatment. In addition, autophagy inhibition improved the therapeutic effect of RCE‑4. These data highlight RCE‑4 as a potential candidate for cervical cancer treatment.

GSK343 induces programmed cell death through the inhibition of EZH2 and FBP1 in osteosarcoma cells

Enhancer of zeste homolog 2 (EZH2) is an important member of the epigenetic regulatory factor polycomb group proteins (PcG) and is abnormally expressed in a wide variety of tumors, including osteosarcoma. Scientists consider EZH2 as an attractive target for the treatment of osteosarcoma and have found many potential EZH inhibitors, such as GlaxoSmithKline 343 (GSK343). It has been reported that GSK343 can be used as an inhibitor in different types of cancer. This study demonstrated that GSK343 not only induced apoptosis by increasing cleaved Casp-3 and poly ADP-ribose polymerase (PARP) expression, but also induced autophagic cell death by inhibiting p62 expression. Apoptosis and autophagic cell death induced by GSK343 were confirmed by the high expression of cleaved caspase-3, LC3-II and transmission electron microscopy. GSK343 inhibited the expression of EZH2 and c-Myc. Additionally, GSK343 inhibited the expression of FUSE binding protein 1 (FBP1), which was identified by its regulatory effects on c-Myc expression. Since c-Myc is a common target of EZH2 and FBP1, and GSK343 inhibited the expression of these proliferation-promoting proteins, a mutual regulatory mechanism between EZH2 and FBP1 was proposed. The knockdown of EZH2 suppressed the expression of FBP1; similarly, the knockdown of FBP1 suppressed the expression of EZH2. These results suggest the mutual regulatory association between EZH2 and FBP1. The knockdown of either EZH2 or FBP1 accelerated the sensitivity of osteosarcoma cells to GSK343. Based on these results, this study clarified that GSK343, an EZH2 inhibitor, may have potential for use in the treatment of osteosarcoma. The underlying mechanisms of the effects of GSK343 are partly mediated by its inhibitory activity against c-Myc and its regulators (EZH2 and FBP1).

Methyloleanolate Induces Apoptotic And Autophagic Cell Death Via Reactive Oxygen Species Generation And c-Jun N-terminal Kinase Phosphorylation

Background

To develop a potent anticancer agent similar to oleanolate, the underlying mechanisms of its derivative, methyloleanolate, in the apoptosis and autophagy of A549 and H1299 cells were elucidated.

Purpose

The aim of the present study was to investigate the effect of methyloleanolate in inducing apoptotic and autophagic cell death in cancer cells.

Materials and methods

Flow cytometric analysis with Annexin V/PI staining, Western blot analysis, and immunofluorescence analysis were conducted in A549 and H1299 cells.

Results

Methyloleanolate increased the fraction of Annexin V/PI apoptotic cells and activated caspase-8, caspase-3, and death receptor 5 (DR5) more than oleanolate in A549 and H1299 cells pretreated with pancaspase inhibitor z-VAD-fmk and DR5 depletion. Also, methyloleanolate induced autophagic features of microtubule-associated protein light chain 3 3BII (LC3BII) conversion and puncta in A549 and H1299 cells, along with autophagosomes and vacuoles. Methyloleanolate blocked autophagy flux for impaired autophagy and chloroquine (CQ)-enhanced microtubule-associated protein LC3BII accumulation and cytotoxicity in A549 and H1299 cells, although 3-methyladenine (3-MA) did not. Interestingly, LC3BII accumulation was detected only in methyloleanolate-treated autophagy-related gene 5 (ATG5)^+/+ mouse embryonic fibroblast (MEF) cells but not in ATG5 ^-/- MEF cells. Methyloleanolate reduced p-mTOR but activated p-c-Jun N-terminal kinases and reactive oxygen species production in A549 and H1299 cells. Conversely, n-acetyl-l-cysteine and SP600125 blocked apoptotic and autophagic cascades caused by methyloleanolate in A549 and H1299 cells.

Conclusion

Overall, the findings suggest that methyloleanolate induces apoptotic and autophagic cell death in non-small cell lung cancers via reactive oxygen species generation and c-Jun N-terminal kinase phosphorylation.

Long Non-Coding RNAs (lncRNAs) Tumor-Suppressive Role of lncRNA on Chromosome 8p12 (TSLNC8) Inhibits Tumor Metastasis and Promotes Apoptosis by Regulating Interleukin 6 (IL-6)/Signal Transducer and Activator of Transcription 3 (STAT3)/Hypoxia-Inducible Factor 1-alpha (HIF-1α) Signaling Pathway in Non-Small Cell Lung Cancer

BACKGROUND Long non-coding RNAs (lncRNAs) exert various functions in human cancers. However, the biological functions of lncRNAs in non-small cell lung cancer (NSCLC) are unknown. In the present study we investigated the tumor-suppressive role of lncRNA on chromosome 8p12 (TSLNC8) in the pathogenesis and progression of NSCLC. MATERIAL AND METHODS qRT-PCR was carried out to evaluate the expression of TSLNC8 in lung cancer cell lines. The effects of TSLNC8 on A549 cells proliferation, migration, and invasion were analyzed using CCK-8 assay, wound healing assay, Transwell assay, and Western blot analysis. We used flow cytometry to assess cell apoptosis, and cell autophagy was assessed by Western blot analysis and immunofluorescence staining. Levels of proteins in the IL-6/STAT3/HIF-1alpha pathway were measured by Western blot analysis. RESULTS The results revealed that TSLNC8 was significantly downregulated in lung cancer cells compared to normal bronchial epithelial cells. Further experiments showed that overexpression of TSLNC8 in A549 cells significantly inhibited proliferation in a time-dependent manner and promoted cell apoptosis. We found that TSLNC8 overexpression suppressed cell migration and invasion, and upregulation of TSLNC8 regulated the protein levels of Beclin-1, p62, ATG14, and LC3-II and inhibited the IL-6/STAT3/HIF-1alpha signaling pathway. CONCLUSIONS lncRNA TSLNC8 remarkably inhibited the proliferation and migration and accelerated apoptosis of lung cancer cells by targeting the IL-6/STAT3/HIF-1alpha signaling pathway. TSLNC8 may be a potential therapeutic target for the diagnosis and treatment of NSCLC.

Contribution of Oxidative Stress and Impaired Biogenesis of Pancreatic β-Cells to Type 2 Diabetes

Significance: Type 2 diabetes development involves multiple changes in β-cells, related to the oxidative stress and impaired redox signaling, beginning frequently by sustained overfeeding due to the resulting lipotoxicity and glucotoxicity. Uncovering relationships among the dysregulated metabolism, impaired β-cell "well-being," biogenesis, or cross talk with peripheral insulin resistance is required for elucidation of type 2 diabetes etiology. Recent Advances: It has been recognized that the oxidative stress, lipotoxicity, and glucotoxicity cannot be separated from numerous other cell pathology events, such as the attempted compensation of β-cell for the increased insulin demand and dynamics of β-cell biogenesis and its "reversal" at dedifferentiation, that is, from the concomitantly decreasing islet β-cell mass (also due to transdifferentiation) and low-grade islet or systemic inflammation. Critical Issues: At prediabetes, the compensation responses of β-cells, attempting to delay the pathology progression-when exaggerated-set a new state, in which a self-checking redox signaling related to the expression of Ins gene expression is impaired. The resulting altered redox signaling, diminished insulin secretion responses to various secretagogues including glucose, may lead to excretion of cytokines or chemokines by β-cells or excretion of endosomes. They could substantiate putative stress signals to the periphery. Subsequent changes and lasting glucolipotoxicity promote islet inflammatory responses and further pathology spiral. Future Directions: Should bring an understanding of the β-cell self-checking and related redox signaling, including the putative stress signal to periphery. Strategies to cure or prevent type 2 diabetes could be based on the substitution of the "wrong" signal by the "correct" self-checking signal.

Early feeding of rainbow trout (Oncorhynchus mykiss) with methionine-deficient diet over a 2 week period: consequences for liver mitochondria in juveniles

Methionine is a key factor in modulating the cellular availability of the main biological methyl donor S-adenosylmethionine (SAM), which is required for all biological methylation reactions including DNA and histone methylation. As such, it represents a potential critical factor in nutritional programming. Here, we investigated whether early methionine restriction at first feeding could have long-term programmed metabolic consequences in rainbow trout. For this purpose, trout fry were fed with either a control diet (C) or a methionine-deficient diet (MD) for 2 weeks from the first exogenous feeding. Next, fish were subjected to a 5 month growth trial with a standard diet followed by a 2 week challenge (with the MD or C diet) to test the programming effect of the early methionine restriction. The results showed that, whatever the dietary treatment of fry, the 2 week challenge with the MD diet led to a general mitochondrial defect associated with an increase in endoplasmic reticulum stress, mitophagy and apoptosis, highlighting the existence of complex cross-talk between these different functions. Moreover, for the first time, we also observed that fish fed the MD diet at the first meal later exhibited an increase in several critical factors of mitophagy, hinting that the early nutritional stimulus with methionine deficiency resulted in long-term programming of this cell function. Together, these data extend our understanding of the role of dietary methionine and emphasize the potential for this amino acid in the application of new feeding strategies, such as nutritional programming, to optimize the nutrition and health of farmed fish.

Prodigiosin stimulates endoplasmic reticulum stress and induces autophagic cell death in glioblastoma cells

Prodigiosin, a secondary metabolite isolated from marine Vibrio sp., has antimicrobial and anticancer properties. This study investigated the cell death mechanism of prodigiosin in glioblastoma. Glioblastoma multiforme (GBM) is an aggressive primary cancer of the central nervous system. Despite treatment, or standard therapy, the median survival of glioblastoma patients is about 14.6 month. The results of the present study clearly showed that prodigiosin significantly reduced the cell viability and neurosphere formation ability of U87MG and GBM8401 human glioblastoma cell lines. Moreover, prodigiosin with fluorescence signals was detected in the endoplasmic reticulum and found to induce excessive levels of autophagy. These findings were confirmed by observation of LC3 puncta formation and acridine orange staining. Furthermore, prodigiosin caused cell death by activating the JNK pathway and decreasing the AKT/mTOR pathway in glioblastoma cells. Moreover, we found that the autophagy inhibitor 3-methyladenine reversed prodigiosin induced autophagic cell death. These findings of this study suggest that prodigiosin induces autophagic cell death and apoptosis in glioblastoma cells.

Chlorogenic acid protects PC12 cells against corticosterone-induced neurotoxicity related to inhibition of autophagy and apoptosis

BACKGROUND

There are evidences that chlorogenic acid (CGA) has antidepressant effects, however the underlying molecular mechanism has not been well understood. The aim of the study was to explore the neuroprotective effect of CGA on corticosterone (CORT)-induced PC 12 cells and its mechanism, especially the autophagy pathway.

METHODS

PC12 cells were incubated with CORT (0, 100, 200, 400 or 800 μM) for 24 h, cell viability was measured by MTT assay. PC12 cells were cultured with 400 μM of CORT in the absence or presence of CGA (25 μg/ml) for 24 h, morphologies and specific marker of autophagosome were observed by transmission electron microscope (TEM) and confocal immunofluorescence microscopy, respectively. In addition, PC12 cells were treated with different doses of CGA (0, 6.25, 12.5, 25 or 50 μg/ml) with or without CORT (400 μM) for 24 h, cell viability and changes in the morphology were observed, and further analysis of apoptotic and autophagic proteins, and expression of AKT/mTOR signaling pathway were carried out by Western blot. Specific inhibitors of autophagy 3-Methyladenine (3-MA) and chloroquine (CQ) were added to the PC12 cells cultures to explore the potential role of autophagy in CORT-induced neuronal cell apoptosis.

RESULTS

Besides decreasing PC12 cell activity, CORT could also induce autophagy and apoptosis of PC12 cells, while CGA could reverse these effects. In addition, CGA treatment regulated AKT/mTOR signaling pathway in PC12 cells. CGA, similar to 3-MA and QC, significantly inhibited CORT-induced apoptosis in PC12 cells.

CONCLUSIONS

Our results provide a new molecular mechanism for the treatment of CORT-induced neurotoxicity by CGA, and suggest CGA may be a potential substance which is can alleviate depression.

Polyphyllin VI induces apoptosis and autophagy in human osteosarcoma cells by modulation of ROS/JNK activation

Purpose

Polyphyllin VI, a main active saponin isolated from traditional medicinal plant Paris polyphylla, has exhibited antitumor activities in several cancer cell lines. In the present study, we investigated the antitumor effect of Polyphyllin VI against human osteosarcoma cells (U2OS) and the underlying molecular mechanisms.

Methods

The U2OS cell lines were used to determine the antiproliferative effect of Polyphyllin VI by CCK8 assay. Cell cycle was analyzed by flow cytometry. The Polyphyllin VI-induced apoptosis was determined by Annexin V-APC/7-AAD apoptosis detection kit and JC-1 staining. Meanwhile, the autophagy was determined by acridine orange staining. The apoptosis and autophagy-related proteins were monitored by Western blot assay. Subsequently, intracellular hydrogen peroxide (H₂O₂) and the activation of ROS/JNK pathway were detected.

Results

Polyphyllin VI could potently inhibit cell proliferation by causing G2/M phase arrest. Polyphyllin VI induced mitochondria-mediated apoptosis with the upregulation of proapoptotic proteins Bax and poly ADP-ribose polymerase, and downregulation of antiapoptotic protein Bcl-2 in U2OS cells. Concomitantly, Polyphyllin VI provoked autophagy with the upregulation of critical Atg proteins and accumulation of LC3B-II. Intracellular H₂O₂ production was triggered upon exposure to Polyphyllin VI, which could be blocked by ROS scavenger. Polyphyllin VI dramatically promoted JNK phosphorylation, whereas it decreased the levels of phospho-p38 and ERK.

Conclusion

Our results reveal that Polyphyllin VI may effectively induce apoptosis and autophagy to suppress cell growth via ROS/JNK activation in U2OS cells, suggesting that Polyphyllin VI is a potential drug candidate for the treatment of osteosarcomas.

Origanum majorana Ethanolic Extract Promotes Colorectal Cancer Cell Death by Triggering Abortive Autophagy and Activation of the Extrinsic Apoptotic Pathway

Colorectal cancer is considered as the third leading cause of cancer death. In the present study, we investigated the potential anticancer effect and the molecular mechanism of Origanum majorana ethanolic extract (OME) against human colorectal cancer cells. We showed that OME exhibited strong anti-proliferative activity in a concentration- and time-dependent manner against two human colorectal cancer cell lines (HT-29 and Caco-2). OME inhibited cell viability, colony growth and induced mitotic arrest of HT-29 cells. Also, OME induced DNA damage, triggered abortive autophagy and activated a caspase 3 and 7-dependent extrinsic apoptotic pathway, most likely through activation of the TNFα pathway. Time-course analysis revealed that DNA damage occurred concomitantly with abortive autophagy after 4 h post-OME treatment while apoptosis was activated only 24 h later. Blockade of autophagy initiation, by 3-methyladenine, partially rescued OME-induced cell death. Cell viability arose from 37% in control group to 67% in group pre-treated with 3-MA before addition of OME. Inhibition of apoptosis, however, had a minimal effect on cell viability; it rose from 37% in control group to 43% in group pre-treated with Z-VAD-FMK. We also found that OME downregulated survivin in HT-29 cells. Our findings provide a strong evidence that O. majorana extract possesses strong anti-colon cancer potential, at least, through induction of autophagy and apoptosis. These finding provide the basis for therapeutic potential of O. majorana in the treatment of colon cancer.

Pristimerin induces apoptosis and autophagy via activation of ROS/ASK1/JNK pathway in human breast cancer in vitro and in vivo

Breast cancer is the most common malignant tumor in women, and progress toward long-term survival has stagnated. Pristimerin, a natural quinonemethide triterpenoid, exhibits potential anti-tumor effects on various cancers. However, the underlying mechanism remains poorly understood. In this study, we found that pristimerin reduced the viability of breast cancer cells in vitro and the growth of xenografts in vivo, and these reductions were accompanied by thioredoxin-1 (Trx-1) inhibition and ASK1 and JNK activation. The results showed that pristimerin inhibited cell cycle progression and triggered cell apoptosis and autophagy. Furthermore, we found that the generation of reactive oxygen species (ROS) was a critical mediator in pristimerin-induced cell death. Enhanced ROS generation by pristimerin activated the ASK1/JNK signaling pathway. Inhibition of ROS with N-acetyl cysteine (NAC) significantly decreased pristimerin-induced cell death by inhibiting the phosphorylation of ASK1 and JNK. Taken together, these results suggest a critical role for the ROS/ASK1/JNK pathway in the anticancer activity of pristimerin.