The independence of and associations among apoptosis, autophagy, and necrosis

Renal tubular cell death and inflammation response are regulated by the MAPK-ERK-CREB signaling pathway under hypoxia-reoxygenation injury

Context: Cell death and inflammation response have been found to the primary features of acute kidney injury.Objective: The aim of our study is to figure out the molecular mechanism by which hypoxia-reoxygenation injury affects the viability of tubular cell death.Materials and methods: HK2 cells were treated with hypoxia-reoxygenation injury in vitro. Pathway agonist was added into the medium of HK2 cell to activate MAPK-EEK-CREB axis.Results: Hypoxia-reoxygenation injury reduced HK2 cell viability and increased cell apoptosis rate in vitro. Besides, inflammation response has been found to be induced by hypoxia-reoxygenation injury in HK2 cells in vitro. In addition, MAPK-ERK-CREB pathway was deactivated during hypoxia-reoxygenation injury. Interestingly, activation of MAPK-ERK-CREB pathway could attenuate hypoxia-reoxygenation injury-mediated HK2 cell apoptosis and inflammation. Mechanistically, MAPK-ERK-CREB pathway activation upregulated the transcription of anti-apoptotic genes and reduced the levels of pro-apoptotic factors under hypoxia-reoxygenation injury.Conclusions: Our results report a novel signaling pathway responsible for acute kidney injury-related tubular cell death. Activation of MAPK-ERK-CREB signaling could protect tubular cell against hypoxia-reoxygenation-related cell apoptosis and inflammation response.

Anti‑survival and pro‑apoptotic effects of meridianin C derivatives on MV4‑11 human acute myeloid leukemia cells

Meridianin C is a marine natural product with anticancer activity. Several meridianin C derivatives (compounds 7a‑j) were recently synthesized, and their inhibitory effects on pro‑viral integration site for Moloney murine leukemia virus (PIM) kinases, as well as their antiproliferative effects on human leukemia cells, were reported. However, the anti‑leukemic effects and mechanisms of action of meridianin C and its derivatives remain largely unknown. The aim of the present study was to investigate the effects of meridianin C and its derivatives on MV4‑11 human acute myeloid leukemia cell growth. The parent compound meridianin C did not markedly affect the viability and survival of MV4‑11 cells. By contrast, MV4‑11 cell viability and survival were reduced by meridianin C derivatives, with compound 7a achieving the most prominent reduction. Compound 7a notably inhibited the expression and activity of PIM kinases, as evidenced by reduced B‑cell lymphoma‑2 (Bcl‑2)‑associated death promoter phosphorylation at Ser112. However, meridianin C also suppressed PIM kinase expression and activity, and the pan‑PIM kinase inhibitor AZD1208 only slightly suppressed the survival of MV4‑11 cells. Thus, the anti‑survival effect of compound 7a on MV4‑11 cells was unrelated to PIM kinase inhibition. Moreover, compound 7a induced apoptosis, caspase‑9 and ‑3 activation and poly(ADP‑ribose) polymerase (PARP) cleavage, but did not affect death receptor (DR)‑4 or DR‑5 expression in MV4‑11 cells. Compound 7a also induced the generation of cleaved Bcl‑2, and the downregulation of myeloid cell leukemia (Mcl)‑1 and X‑linked inhibitor of apoptosis (XIAP) in MV4‑11 cells. Furthermore, compound 7a increased eukaryotic initiation factor (eIF)‑2α phosphorylation and decreased S6 phosphorylation, whereas GRP‑78 expression was unaffected. Importantly, treatment with a pan‑caspase inhibitor (z‑VAD‑fmk) significantly attenuated compound 7a‑induced apoptosis, caspase‑9 and ‑3 activation, PARP cleavage, generation of cleaved Bcl‑2 and downregulation of Mcl‑1 and XIAP in MV4‑11 cells. Collectively, these findings demonstrated the strong anti‑survival and pro‑apoptotic effects of compound 7a on MV4‑11 cells through regulation of caspase‑9 and ‑3, Bcl‑2, Mcl‑1, XIAP, eIF‑2α and S6 molecules.

Molecular Mechanisms Involved in the Antitumor Activity of Isolated Lectins from Marine Organisms: A Systematic Review

INTRODUCTION

Tumor cells may present several molecular alterations that favor their malignancy, among which there is the expression of tumor-related antigens, such as truncated T-glycans, Thomsen-nouvelle, sialyl-Lewis X and sialyl Tn, which may help in the diagnosis and treatment using specific target molecules. Lectins are ubiquitous proteins capable of interacting with specific carbohydrates. Lectins isolated from marine organisms have important characteristics such as low immunogenicity and can bind to complex glycans compared to plant lectins.

OBJECTIVE

This work evaluated, through a systematic review, the molecular mechanisms of antitumor activity of lectins isolated from marine organisms.

METHODOLOGY

The Pubmed, Lilacs, Science Direct, Wiley and Scopus databases were reviewed using the descriptors: marine lectin and cancer. Articles in English, published between January 2008 and December 2018, which proposed the molecular mechanisms of anticancer activity of lectins from marine organisms were eligible for the study.

RESULTS

17 articles were eligible. The lectins showed promising performance against cancer cells, presenting specific cytotoxicity for some types of malignant cells. The articles presented several lectins specific to different carbohydrates, modulating: pro and anti-apoptotic proteins, transcription factor E2F-1, via mitogen-activated protein kinase. In addition, exogenous lectin expression in cancer cells has been shown to be a promising way to treat cancer.

CONCLUSION

This review showed the various studies that described the molecular mechanisms caused by marine lectins with antineoplastic potential. This knowledge is relevant for the development and use of the next generations of lectins isolated from marine organisms, supporting their potential in cancer treatment.

A Novel Role for Necroptosis in the Pathogenesis of Necrotizing Enterocolitis

BACKGROUND & AIMS

Necrotizing enterocolitis (NEC) is a devastating disease of premature infants characterized by Toll-like receptor 4 (TLR4)-dependent intestinal inflammation and enterocyte death. Given that necroptosis is a proinflammatory cell death process that is linked to bacterial signaling, we investigated its potential role in NEC, and the mechanisms involved.

METHODS

Human and mouse NEC intestine were analyzed for necroptosis gene expression (ie, RIPK1, RIPK3, and MLKL), and protein activation (phosphorylated RIPK3). To evaluate a potential role for necroptosis in NEC, the effects of genetic (ie, Ripk3 knockout or Mlkl knockout) or pharmacologic (ie, Nec1s) inhibition of intestinal inflammation were assessed in a mouse NEC model, and a possible upstream role of TLR4 was assessed in Tlr4-deficient mice. The NEC-protective effects of human breast milk and its constituent milk oligosaccharides on necroptosis were assessed in a NEC-in-a-dish model, in which mouse intestinal organoids were cultured as either undifferentiated or differentiated epithelium in the presence of NEC bacteria and hypoxia.

RESULTS

Necroptosis was activated in the intestines of human and mouse NEC in a TLR4-dependent manner, and was up-regulated specifically in differentiated epithelium of the immature ileum. Inhibition of necroptosis genetically and pharmacologically reduced intestinal-epithelial cell death and mucosal inflammation in experimental NEC, and ex vivo in the NEC-in-a-dish system. Strikingly, the addition of human breast milk, or the human milk oligosaccharide 2 fucosyllactose in the ex vivo system, reduced necroptosis and inflammation.

CONCLUSIONS

Necroptosis is activated in the intestinal epithelium upon TLR4 signaling and is required for NEC development, and explains in part the protective effects of breast milk.

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.

Function of flavonoids on different types of programmed cell death and its mechanism: a review

Cell death in the living system plays a vital role in maintaining the homeostasis and balancing the cell count in the body. Programmed cell death (PCD) is a crucial component of several development and defense mechanisms. PCD is also important in terms of aging which avoids the accumulation of cellular damage by maintaining cell division. Depending on the execution of cell death and its role in destruction, PCD is categorized into several subtypes. The major different forms of PCD in animals are apoptosis, autophagy and necrosis, which can be distinct in morphological terms. More intense investigations of cell death have given close insight showing other important types of cellular destruction and their pivotal roles in treating disease conditions like cancer. Flavonoids have been acquired a great interest for disease therapies and chemoprevention through activation of several PCD mechanisms. The significant potential of natural flavonoids in the induction of distinct signaling cascades is being a massive approach for targeting uncontrolled cell growth. For these reasons, understanding PCD mechanisms is a promising approach for the interventions in treating cancer. Thus, it is intriguing that understanding the different forms of PCD mechanism induced by flavonoids with more accurate descriptions on the biochemical and cellular processes are gaining more significance in cancer research. Here, we provide a brief overview on the different types of PCD and aim to discuss the functional role of flavonoids in promoting different types of cell death as well as an extensive brief review on their mechanism of action has been highlighted.

The Effect of Biotinylated PAMAM G3 Dendrimers Conjugated with COX-2 Inhibitor (celecoxib) and PPARγ Agonist (Fmoc-L-Leucine) on Human Normal Fibroblasts, Immortalized Keratinocytes and Glioma Cells in Vitro

Glioblastoma multiforme (GBM) is the most malignant type of central nervous system tumor that is resistant to all currently used forms of therapy. Thus, more effective GBM treatment strategies are being investigated, including combined therapies with drugs that may cross the blood brain barrier (BBB). Another important issue considers the decrease of deleterious side effects of therapy. It has been shown that nanocarrier conjugates with biotin can penetrate BBB. In this study, biotinylated PAMAM G3 dendrimers substituted with the recognized anticancer agents cyclooxygenase-2 (COX-2) inhibitor celecoxib and peroxisome proliferator-activated receptor γ (PPARγ) agonist Fmoc-L-Leucine (G3-BCL) were tested in vitro on human cell lines with different p53 status: glioblastoma (U-118 MG), normal fibroblasts (BJ) and immortalized keratinocytes (HaCaT). G3-BCL penetrated efficiently into the lysosomal and mitochondrial compartments of U-118 MG cells and induced death of U-118 MG cells via apoptosis and inhibited proliferation and migration at low IC₅₀ = 1.25 µM concentration, considerably lower than either drug applied alone. Comparison of the effects of G3-BCL on expression of COX-2 and PPARγ protein and PGE₂ production of three different investigated cell line phenotypes revealed that the anti-glioma effect of the conjugate was realized by other mechanisms other than influencing PPAR-γ expression and regardless of p53 cell status, it was dependent on COX-2 protein level and high PGE₂ production. Similar G3-BCL cytotoxicity was seen in normal fibroblasts (IC₅₀ = 1.29 µM) and higher resistance in HaCaT cells (IC₅₀ = 4.49 µM). Thus, G3-BCL might be a good candidate for the targeted, local glioma therapy with limited site effects.

MKP1 reduces neuroinflammation via inhibiting endoplasmic reticulum stress and mitochondrial dysfunction

MAP kinase phosphatase 1 (MKP1) has been identified as an antiapoptotic protein via sustaining mitochondrial function. However, the role of MKP1 in neuroinflammation has not been fully understood. The aim of this study is to figure out the influence of MKP1 in lipopolysaccharide (LPS)-treated microglia BV-2 cells and investigate whether MKP1 reduces BV-2 cell death via modulating endoplasmic reticulum (ER) stress and mitochondrial dysfunction. The results of this study demonstrated that MKP1 was rapidly downregulated after exposure to LPS. However, the transfection of MKP1 adenovirus could reverse cell viability and attenuate LPS-mediated BV-2 cell apoptosis. Mechanistically, MKP1 overexpression alleviated ER stress and corrected LPS-induced calcium overloading. Besides, MKP1 adenovirus transfection also reversed mitochondrial bioenergetics, maintained mitochondrial membrane potential, and blocked mitochondria-initiated apoptosis signals. Furthermore, we found that MKP1 overexpression is associated with inactivation of mitogen-activated protein kinase-c-Jun N-terminal kinase (MAPK-JNK) pathway. Interestingly, the activation of MAPK-JNK pathway could abolish the protective effects of MKP1 on BV-2 cells survival and mitochondrial function in the presence of LPS. Altogether, our results identified MKP1 as a primary defender of neuroinflammation via modulating ER stress and mitochondrial function in a manner dependent on MAPK-JNK pathway. These findings may open a new window for the treatment of neuroinflammation in the clinical setting.

The Antitumor Potential of Extract of the Oak Bracket Medicinal Mushroom Inonotus baumii in SMMC-7721 Tumor Cells

Inonotus baumii, a traditional medicinal mushroom, has been historically used in China and other countries of East Asia for the treatment of various diseases. The aim of this study is to investigate the antitumor activity of the extract of I. baumii (EIB) against hepatocellular carcinoma and the possible mechanism involved. The MTT assay was used to evaluate the proliferative activity of SMMC-7721 cells treated with EIB. Hoechst 33258 and JC-1 staining were used to determine nuclear morphological changes and mitochondrial membrane potential, respectively. Flow cytometry analysis indicated that EIB blocked the cell cycle at the S phase and induced significant apoptosis. EIB increased the protein expression of Bax, cytochrome c, cleaved caspase-3, and decreased Bcl-2 in SMMC-7721. Moreover, EIB induced autophagy, indicated by the increase of autophagy-related protein expression of LC3-II and decrease of p62, and the AMPK/mTOR/ULK1 pathway was involved in the autophagic cell death. In vivo, EIB was found to strongly inhibit the growth of tumors in BALB/c nude mice. Our results indicated that I. baumii might be a potential natural therapeutic agent for liver cancer, as it could induce apoptosis and autophagy in HCC cells.

Antipsychotic Drug Trifluoperazine Suppresses Colorectal Cancer by Inducing G0/G1 Arrest and Apoptosis

Repurposing existing drugs for cancer treatment is an effective strategy. An approved antipsychotic drug, trifluoperazine (TFP), has been reported to have potential anticancer effects against several cancer types. Here, we investigated the effect and molecular mechanism of TFP in colorectal cancer (CRC). In vitro studies showed that TFP induced G0/G1 cell cycle arrest to dramatically inhibit CRC cell proliferation through downregulating cyclin-dependent kinase (CDK) 2, CDK4, cyclin D1, and cyclin E and upregulating p27. TFP also induced apoptosis, decreased mitochondrial membrane potential, and increased reactive oxygen species levels in CRC cells, indicating that TFP induced mitochondria-mediated intrinsic apoptosis. Importantly, TFP significantly suppressed tumor growth in two CRC subcutaneous tumor models without side effects. Interestingly, TFP treatment increased the expression levels of programmed death-1 ligand 1 (PD-L1) in CRC cells and programmed death-1 (PD-1) in tumor-infiltrating CD4+ and CD8+ T cells, implying that the combination of TFP with an immune checkpoint inhibitor, such as an anti-PD-L1 or anti-PD-1 antibody, might have synergistic anticancer effects. Taken together, our study signifies that TFP is a novel treatment strategy for CRC and indicates the potential for using the combination treatment of TFP and immune checkpoint blockade to increase antitumor efficiency.

A Cyclic Pentamethinium Salt Induces Cancer Cell Cytotoxicity through Mitochondrial Disintegration and Metabolic Collapse

Cancer cells preferentially utilize glycolysis for ATP production even in aerobic conditions (the Warburg effect) and adapt mitochondrial processes to their specific needs. Recent studies indicate that altered mitochondrial activities in cancer represent an actionable target for therapy. We previously showed that salt 1-3C, a quinoxaline unit (with cytotoxic activity) incorporated into a meso-substituted pentamethinium salt (with mitochondrial selectivity and fluorescence properties), displayed potent cytotoxic effects in vitro and in vivo, without significant toxic effects to normal tissues. Here, we investigated the cytotoxic mechanism of salt 1-3C compared to its analogue, salt 1-8C, with an extended side carbon chain. Live cell imaging demonstrated that salt 1-3C, but not 1-8C, is rapidly incorporated into mitochondria, correlating with increased cytotoxicity of salt 1-3C. The accumulation in mitochondria led to their fragmentation and loss of function, accompanied by increased autophagy/mitophagy. Salt 1-3C preferentially activated AMP-activated kinase and inhibited mammalian target of rapamycin (mTOR) signaling pathways, sensors of cellular metabolism, but did not induce apoptosis. These data indicate that salt 1-3C cytotoxicity involves mitochondrial perturbation and disintegration, and such compounds are promising candidates for targeting mitochondria as a weak spot of cancer.

Medicinal Plants from Brazilian Cerrado: Antioxidant and Anticancer Potential and Protection against Chemotherapy Toxicity

The use of natural antioxidants in cancer therapy has increased: first, due to the potential of natural antioxidants to kill tumour cells and second, because of their capacity to protect healthy cells from the damage caused by chemotherapy. This review article discusses the antioxidant properties of extracts obtained from medicinal plants from the Brazilian Cerrado and the cell death profile induced by each of these extracts in malignant cells. Next, we describe the capacity of other medicinal plants from the Cerrado to protect against chemotherapy-induced cell toxicity. Finally, we focus on recent insights into the cell death profile induced by extracts from Cerrado plants and perspectives for future therapeutic approaches.

Inhibitor of apoptosis proteins are potential targets for treatment of granulosa cell tumors - implications from studies in KGN

Background

Granulosa cell tumors (GCTs) are derived from proliferating granulosa cells of the ovarian follicle. They are known for their late recurrence and most patients with an aggressive form die from their disease. There are no treatment options for this slowly proliferating tumor besides surgery and chemotherapy. In a number of tumors, analogs of the second mitochondria-derived activator of caspases (SMAC), alone or in combination with other molecules, such as TNFα, are evolving as new treatment options. SMAC mimetics block inhibitor of apoptosis proteins (IAPs), which bind caspases (e.g. XIAP), or activate the pro-survival NF-κB pathway (e.g. cIAP1/2). Expression of IAPs by GCTs is yet not fully elucidated but recently XIAP and its inhibition by SMAC mimetics in a combination therapy was described to induce apoptosis in a GCT cell line, KGN. We evaluated the expression of cIAP1 in GCTs and elucidated the effects of the SMAC mimetic BV-6 using KGN as a model.

Results

Employing immunohistochemistry, we observed cIAP1 expression in a tissue microarray (TMA) of 42 GCT samples. RT-PCR confirmed expression of cIAP1/2, as well as XIAP, in primary, patient-derived GCTs and in KGN. We therefore tested the ability of the bivalent SMAC mimetic BV-6, which is known to inhibit cIAP1/2 and XIAP, to induce cell death in KGN. A dose response study indicated an EC₅₀ ≈ 8 μM for both, early (< 8) and advanced (> 80) passages, which differ in growth rate and presumably aggressiveness. Quantitative RT-PCR showed upregulation of NF-κB regulated genes in BV-6 stimulated cells. Blocking experiments with the pan-caspase inhibitor Z-VAD-FMK indicated caspase-dependence. A concentration of 20 μM Z-VAD-FMK was sufficient to significantly reduce apoptosis. This cell death was further substantiated by results of Western Blot studies. Cleaved caspase 3 and cleaved PARP became evident in the BV-6 treated group.

Conclusions

Taken together, the results show that BV-6 is able to induce apoptosis in KGN cells. This approach may therefore offer a promising therapeutic avenue to treat GCTs.

Electronic supplementary material

The online version of this article (10.1186/s13048-019-0549-6) contains supplementary material, which is available to authorized users.

Ripk3 mediates cardiomyocyte necrosis through targeting mitochondria and the JNK-Bnip3 pathway under hypoxia-reoxygenation injury

Context: Cardiomyocyte necrosis following myocardial infarction drastically the progression of heart failure.Objective: In the current study, we explored the upstream mediator for cardiomyocytes necrosis induced by hypoxia-reoxygenation (HR) injury with a focus on mitochondrial function and JNK-Bnip3 pathway.Materials and methods: Cell necrosis was determined via MTT assay, TUNEL staining and PI staining. siRNA transfection was performed to inhibit Ripk3 activation in response to HR injury. Pathway blocker was applied to prevent JNK activation.Results: Ripk3 was rapidly increased in HR-treated cardiomyocytes and correlated with the necrosis of cardiomyocytes. Interestingly, silencing of Ripk3 attenuated HR-mediated cardiomyocytes necrosis. At the molecular levels, Ripk3 deletion sustained mitochondrial bioenergetics and stabilized mitochondrial glucose metabolism. Besides, Ripk3 deletion also reduced mitochondrial oxidative stress and inhibited mPTP opening. To the end, we found Ripk3 activation was along with JNK pathway activation and Bnip3 upregulation. Interestingly, blockade of JNK pathway abolished the harmful effects of HR injury on mitochondrial function, energy metabolism and redox balance. Moreover, overexpression of Bnip3 abrogated the protection action played by Ripk3 deletion on cardiomyocytes survival.Conclusions: Taken together, these data may identify Ripk3 upregulation, mitochondrial dysfunction and JNK-Bnip3 axis activation as the novel mechanisms underlying cardiomyocytes necrosis achieved by HR injury. Thereby, approaches targeted to the Ripk3-JNK-Bnip3-mitochondria cascade have the potential to ameliorate the progression of HR-related cardiomyocytes necrosis in the clinical practice.

Development of a novel method for the purification of C-phycocyanin pigment from a local cyanobacterial strain Limnothrix sp. NS01 and evaluation of its anticancer properties

C-phycocyanin (C-PC) pigment, as a natural blue dye, has particular applications in various fields. It is a water-soluble protein which has anticancer, antioxidant and anti-inflammatory properties. Here, we introduce an efficient procedure for the purification of C-PC pigment, followed by conducting a comprehensive investigation of its cytotoxic effects on human breast cancer (MCF-7) cells and the underlying mechanisms. A novel four-step purification procedure including the adsorption of impurities with chitosan, activated charcoal, ammonium sulfate precipitation, and ion exchange chromatography was employed, achieving a high purity form of C-PC with purity index (PI) of 5.26. SDS-PAGE analysis showed the purified C-PC with two discrete bands, subunit α (17 kD) and β (20 kD), as confirmed its identity by Native-PAGE. A highly purified C-PC was employed to evaluate its anticancer activity and underlying molecular mechanisms of action. The inhibitory effects of highly purified C-PC on the proliferation of human breast cancer cells (MCF-7) have detected by MTT assay. The IC50 values for 24, 48, and 72 hours of exposure to C-PC were determined to be 5.92, 5.66, and 4.52 μg/μl, respectively. Flow cytometric analysis of cells treated with C-PC, by Annexin V/PI double staining, demonstrated to induce MCF-7 cells apoptosis. Also, the results obtained from propidium iodide (PI) staining showed that MCF-7 cells treated with 5.92 μg/μl C-PC for 24 h would arrest at the G2 phase and 5.66 and 4.52 μg/μl C-PC for 48 and 72 h could induce cell cycle arrest at both G2 and S phases. The oxidative damage and mitochondrial dysfunction were evaluated to determine the possible pathways involved in C-PC-induced apoptosis in MCF-7 cells. Our findings clearly indicated that the treatment of MCF-7 cells with C-PC (IC50 for 24 h) increased the production of reactive oxygen species (ROS). Consequently, an increase in the lipid peroxidation (LPO) level and a reduction in the ATP level, mitochondrial membrane potential (MMP), glutathione (GSH) and its oxidized form (GSSG), occurred over time. The reduced expression levels of anti-apoptotic proteins, Bcl2 and Stat3, plus cell cycle regulator protein, Cyclin D1, using Real-Time PCR confirm that the C-PC-induced death of MCF-7 human breast cancer cells occurred through the mitochondrial pathway of apoptosis. Collectively, the analyses presented here suggest that C-PC has the potential so that to develop it as a chemotherapeutic anticancer drug.

2,3',4,4',5-Pentachlorobiphenyl induced autophagy of the thyrocytes via DAPK2/PKD/VPS34 pathway

2,3',4,4',5-Pentachlorobiphenyl (PCB118) has been shown to cause thyroidal ultrastructure lesions, but the underlying mechanism remains elusive. This study aimed to elucidate the mechanism by which PCB118 induces the abnormalities of the thyrocytes. Wistar rats were injected intraperitoneally with PCB118 (0, 10, 100 and 1000 μg/kg/d) for 13 weeks, and FRTL-5 cells were treated with PCB118 (0, 0.25, 2.5 and 25 nM). Transmission electron microscopy showed typical autophagosomes in the thyroid of PCB118-treated rats. Immunofluorescence staining showed dose-dependent increase of autophagy in FRTL-5 cells exposed to PCB118. In vivo and vitro studies found that Tubulin beta 3 class III (Tubb3) mRNA and protein levels decreased significantly, while Death-associated protein kinase 2 (DAPK2) increased after PCB118 exposure, and the binding between Tubb3 and DAPK2 was enhanced by PCB118 in a dose-dependent manner. Moreover, PCB118 resulted in the upregulation of Protein kinase D (PKD) and downregulation of Phosphatidylinositol 3-kinase (VPS34) in mRNA levels, and the activation of PKD and VPS34 phosphorylation. Additionally, Tubb3 small interfering RNA (siTubb3) suppressed DAPK2 protein expression and PKD phosphorylation in FRTL-5 cells, while VPS34 phosphorylation was inhibited by siPKD. Furthermore, DAPK2, PKD and VPS34 were upregulated by Tubb3 overexpression following PCB118 exposure. Our results demonstrate that low concentrations of PCB118 could promote thyroid autophagy formation and cause the abnormalities in thyroidal ultrastructure, and these effects are likely to be mediated by DAPK2/PKD/VPS34 dependent pathway.

Macrophage Death as a Pharmacological Target in Atherosclerosis

Atherosclerosis is a chronic inflammatory disorder characterized by the gradual build-up of plaques within the vessel wall of middle-sized and large arteries. Over the past decades, treatment of atherosclerosis mainly focused on lowering lipid levels, which can be accomplished by the use of statins. However, some patients do not respond sufficiently to statin therapy and therefore still have a residual cardiovascular risk. This issue highlights the need for novel therapeutic strategies. As macrophages are implicated in all stages of atherosclerotic lesion development, they represent an important alternative drug target. A variety of anti-inflammatory strategies have recently emerged to treat or prevent atherosclerosis. Here, we review the canonical mechanisms of macrophage death and their impact on atherogenesis and plaque stability. Macrophage death is a prominent feature of advanced plaques and is a major contributor to necrotic core formation and plaque destabilization. Mechanisms of macrophage death in atherosclerosis include apoptosis, passive or accidental necrosis as well as secondary necrosis, a type of death that typically occurs when apoptotic cells are insufficiently cleared by neighboring cells via a phagocytic process termed efferocytosis. In addition, less-well characterized types of regulated necrosis in macrophages such as necroptosis, pyroptosis, ferroptosis, and parthanatos may occur in advanced plaques and are also discussed. Autophagy in plaque macrophages is an important survival pathway that protects against cell death, yet massive stimulation of autophagy promotes another type of death, usually referred to as autosis. Multiple lines of evidence indicate that a better insight into the different mechanisms of macrophage death, and how they mutually interact, will provide novel pharmacological strategies to resolve atherosclerosis and stabilize vulnerable, rupture-prone plaques.

A novel triazole, NMK-T-057, induces autophagic cell death in breast cancer cells by inhibiting γ-secretase-mediated activation of Notch signaling

Notch signaling is reported to be deregulated in several malignancies, including breast, and the enzyme γ-secretase plays an important role in the activation and nuclear translocation of Notch intracellular domain (NICD). Hence, pharmacological inhibition of γ-secretase might lead to the subsequent inhibition of Notch signaling in cancer cells. In search of novel γ-secretase inhibitors (GSIs), we screened a series of triazole-based compounds for their potential to bind γ-secretase and observed that 3-(3'4',5'-trimethoxyphenyl)-5-(N-methyl-3'-indolyl)-1,2,4-triazole compound (also known as NMK-T-057) can bind to γ-secretase complex. Very interestingly, NMK-T-057 was found to inhibit proliferation, colony-forming ability, and motility in various breast cancer (BC) cells such as MDA-MB-231, MDA-MB-468, 4T1 (triple-negative cells), and MCF-7 (estrogen receptor (ER)/progesterone receptor (PR)-positive cell line) with negligible cytotoxicity against noncancerous cells (MCF-10A and peripheral blood mononuclear cells). Furthermore, significant induction of apoptosis and inhibition of epithelial-to-mesenchymal transition (EMT) and stemness were also observed in NMK-T-057-treated BC cells. The in silico study revealing the affinity of NMK-T-057 toward γ-secretase was further validated by a fluorescence-based γ-secretase activity assay, which confirmed inhibition of γ-secretase activity in NMK-T-057-treated BC cells. Interestingly, it was observed that NMK-T-057 induced significant autophagic responses in BC cells, which led to apoptosis. Moreover, NMK-T-057 was found to inhibit tumor progression in a 4T1-BALB/c mouse model. Hence, it may be concluded that NMK-T-057 could be a potential drug candidate against BC that can trigger autophagy-mediated cell death by inhibiting γ-secretase-mediated activation of Notch signaling.

Targeting Autophagy to Overcome Human Diseases

Autophagy is an evolutionarily conserved cellular process, through which damaged organelles and superfluous proteins are degraded, for maintaining the correct cellular balance during stress insult. It involves formation of double-membrane vesicles, named autophagosomes, that capture cytosolic cargo and deliver it to lysosomes, where the breakdown products are recycled back to cytoplasm. On the basis of degraded cell components, some selective types of autophagy can be identified (mitophagy, ribophagy, reticulophagy, lysophagy, pexophagy, lipophagy, and glycophagy). Dysregulation of autophagy can induce various disease manifestations, such as inflammation, aging, metabolic diseases, neurodegenerative disorders and cancer. The understanding of the molecular mechanism that regulates the different phases of the autophagic process and the role in the development of diseases are only in an early stage. There are still questions that must be answered concerning the functions of the autophagy-related proteins. In this review, we describe the principal cellular and molecular autophagic functions, selective types of autophagy and the main in vitro methods to detect the role of autophagy in the cellular physiology. We also summarize the importance of the autophagic behavior in some diseases to provide a novel insight for target therapies.

Human Luteinized Granulosa Cells-A Cellular Model for the Human Corpus Luteum

In the ovary, the corpus luteum (CL) forms a temporal structure. Luteinized mural granulosa cells (GCs), which stem from the ruptured follicle, are the main cells of the CL. They can be isolated from follicular fluid of woman undergoing in vitro fertilization. In culture, human GCs are viable for several days and produce progesterone, yet eventually steroid production stops and GCs with increasing time in culture undergo changes reminiscent of the ones observed during the demise of the CL in vivo. This short review summarizes the general use of human GCs as a model for the primate CL and some of the data from our lab, which indicate that viability, functionality, survival and death of GCs can be regulated by local signal molecules (e.g., oxytocin and PEDF) and the extracellular matrix (e.g., via the proteoglycan decorin). We further summarize studies, which identified autophagocytotic events in human GCs linked to the activation of an ion channel. More recent studies identified a form of regulated cell death, namely necroptosis. This form of cell death may, in addition to apoptosis, contribute to the demise of the human CL. We believe that human GCs are a unique window into the human CL. Studies employing these cells may lead to the identification of molecular events and novel targets, which may allow to interfere with CL functions.

Long non-coding RNAs in esophageal cancer: molecular mechanisms, functions, and potential applications

Esophageal cancer (EC) is the sixth leading cause of cancer-related death worldwide. The lack of early diagnostic biomarkers and effective prognostic indicators for metastasis and recurrence has resulted in the poor prognosis of EC. In addition, the underlying molecular mechanisms of EC development have yet to be elucidated. Accumulating evidence has demonstrated that lncRNAs play a vital role in the pathological progression of EC. LncRNAs may regulate gene expression through the recruitment of histone-modifying complexes to the chromatin and through interactions with RNAs or proteins. Recent evidence has demonstrated that the dysregulation of lncRNAs plays important roles in the proliferation, metastasis, invasion, angiogenesis, apoptosis, chemoradiotherapy resistance, and stemness of EC, which suggests potential clinical implications. In this review, we highlight the emerging roles and regulatory mechanisms of lncRNAs in the context of EC and discuss their potential clinical applications as diagnostic and prognostic biomarkers.