Bioactive lipids and the control of Bax pro-apoptotic activity

Identification and functional characterization of the npc-2-like domain containing rust effector protein that suppresses cell death in plants

The MD-2-related lipid-recognition (ML/Md-2) domain is a lipid/sterol-binding domain that are involved in sterol transfer and innate immunity in eukaryotes. Here we report a genome-wide survey of this family, identifying 84 genes in 30 fungi including plant pathogens. All the studied species were found to have varied ML numbers, and expansion of the family was observed in Rhizophagus irregularis (RI) with 33 genes. The molecular docking studies of these proteins with cholesterol derivatives indicate lipid-binding functional conservation across the animal and fungi kingdom. The phylogenetic studies among eukaryotic ML proteins showed that Puccinia ML members are more closely associated with animal (insect) npc2 proteins than other fungal ML members. One of the candidates from leaf rust fungus Puccinia triticina, Pt5643 was PCR amplified and further characterized using various studies such as qRT-PCR, subcellular localization studies, yeast functional complementation, signal peptide validation, and expression studies. The Pt5643 exhibits the highest expression on the 5th day post-infection (dpi). The confocal microscopy of Pt5643 in onion epidermal cells and N. benthamiana shows its location in the cytoplasm and nucleus. The functional complementation studies of Pt5643 in npc2 mutant yeast showed its functional similarity to the eukaryotic/yeast npc2 gene. Furthermore, the overexpression of Pt5643 also suppressed the BAX, NEP1, and H₂O₂-induced program cell death in Nicotiana species and yeast. Altogether the present study reports the novel function of ML domain proteins in plant fungal pathogens and their possible role as effector molecules in host defense manipulation.

KLHDC7B as a novel diagnostic biomarker in urine exosomal mRNA promotes bladder urothelial carcinoma cell proliferation and migration, inhibits apoptosis

Bladder cancer is a common kind of urinary system cancer, in which bladder urothelial carcinoma (BLCA) comprises approximately 90% of all bladder cancer types. In our previous study, we discovered KLHDC7B in urine exosomal messenger RNA (mRNA) as a prospective molecular marker for bladder cancer detection. To systematically study the role and mechanism of KLHDC7B in BLCA, we focused on the most common type of BLCA in this study. First, we used RNA sequencing to discover that KLHDC7B was considerably increased in BLCA patients' urine exosomes compared to healthy controls. Then, we validated this result in an independent cohort and identified it as an effective tool for diagnosing and distinguishing high-grade and low-grade BLCA. Finally, we studied the role and mechanism of KLHDC7B in BLCA at the cellular level, providing a functional basis for its expression as a novel laboratory diagnostic biomarker for BLCA exosomal mRNA, which has important theoretical and clinical significance.

UPP1 enhances bladder cancer progression and gemcitabine resistance through AKT

UPP1, a crucial pyrimidine metabolism-related enzyme, catalyzes the reversible phosphorylation of uridine to uracil and ribose-1-phosphate. However, the effects of UPP1 in bladder cancer (BLCA) have not been elucidated. AKT, which is activated mainly through dual phosphorylation (Thr308 and Ser473), promotes tumorigenesis by phosphorylating downstream substrates. This study demonstrated that UPP1 promotes BLCA cell proliferation, migration, invasion, and gemcitabine resistance by activating the AKT signaling pathway in vitro and in vivo. Additionally, UPP1 promoted AKT activation by facilitating the binding of AKT to PDK1 and PDK2 and the recruitment of phosphatidylinositol 3,4,5-triphosphate to AKT. Moreover, the beneficial effects of UPP1 on BLCA tumorigenesis were mitigated upon UPP1 mutation with Arg94 or MK2206 treatment (AKT-specific inhibitor). AKT overexpression or SC79 (AKT-specific activator) treatment restored tumor malignancy and drug resistance. Thus, this study revealed that UPP1 is a crucial oncogene and a potential therapeutic target for BLCA and that UPP1 activates the AKT signaling pathway and enhances tumorigenesis and drug resistance to gemcitabine.

Ginger as an anticolorectal cancer spice: A systematic review of in vitro to clinical evidence

Ginger and its derivatives have been shown to be effective in the prevention and treatment of cancer. We undertook a systematic review to answer the question of whether ginger has a role in modifying the biomarkers of cancer in cell culture conditions and on colorectal cancer in randomized clinical trials. We performed a comprehensive search of the literature from Scopus, Embase, Web of Science, PubMed, Cochrane central register of controlled trials, and Cochrane database of systematic reviews. At first, all 12 papers studied the effect of ginger or its derivatives on cell culture conditions. The results of cell culture studies show that ginger has a powerful role in inducing apoptosis. In the second part, five studies of clinical trials were analyzed. By analyzing antitumor markers of clinical trials, ginger increased some anticancer markers but performed poorly in inducing some anticancer markers. This systematic review showed that the consumption of ginger extract has the potential to prevent and treat colorectal cancer but this ability is weak.

Diallyl trisulfide plays an antifibrotic role by inhibiting the expression of Bcl‐2 in hepatic stellate cells

Hepatic fibrosis is an important early stage in the evolution of liver cirrhosis, and specific medicine and therapeutic measures are unavailable to date. Hepatic stellate cells (HSCs) are the main cells involved in the formation of hepatic fibrosis, and induction of the apoptosis of HSCs is an important strategy for the treatment of hepatic fibrosis. Diallyl trisulfide (DATS) is a natural product and is the main active ingredient in garlic. However, the exact molecular mechanisms underlying HSC apoptosis induced by DATS are not well understood. This study aimed to analyze the efficiency and mechanism of DATS in hepatic fibrosis. Different concentrations (25, 50, 100, and 200 μM) of DATS were used to treat HSCs. Changes in cell morphology and formation of apoptotic bodies were observed under an inverted microscope and an electric microscope. Bcl‐2 signaling involving Bax, Caspase‐3, Caspase‐6, Caspase‐8, Caspase‐9, p53, Apaf‐1, and Cyto‐c in fibrosis were examined, which is a critical step in the evaluation of antihepatic fibrosis agents. We also evaluated the effect of DATS on the cellular morphology of HSCs and apoptosis‐related factors under different Bcl‐2 expression states. Our results suggest that DATS regulates hepatic fibrosis by blocking the Bcl‐2 signaling pathway and upregulating the Bax/Bcl‐2 ratio.

A kinetic fluorescence polarization ligand assay for monitoring BAX early activation

Developmental, homeostatic, and pharmacological pro-apoptotic signals converge by activating the BCL-2 family member BAX. Studies investigating molecular regulation of BAX are commonly limited to methodologies measuring endpoint phenotypes and do not assess activation of monomeric BAX. Here, we present FLAMBE, a fluorescence polarization ligand assay for monitoring BAX early activation, that measures activation-induced release of a peptide probe in real time. Using complementary parallel and tandem biochemical techniques, we validate, corroborate, and apply FLAMBE to a contemporary repertoire of BAX modulators, characterizing their contributions within the early steps of BAX activation. Additionally, we use FLAMBE to reveal that historically "dead" BAX mutants remain responsive to activation as quasi-functional monomers. We also identify data metrics for comparative analyses and demonstrate that FLAMBE data align with downstream functional observations. Collectively, FLAMBE advances our understanding of BAX activation and fills a methodological void for studying BAX with broad applications in cell biology and therapeutic development. MOTIVATION In vitro BAX activation studies are invaluable platforms for studying cellular and pharmacological modulators of apoptosis. The gold standard for studying BAX function relies on membrane permeabilization assays, which assess the pore-forming activity of oligomeric BAX. However, there are currently no rapid or kinetic assays to interrogate real-time activation of monomeric BAX in solution, thereby limiting any molecular insights that occur upstream of mitochondrial permeabilization. Furthermore, available methods to observe the activation of monomeric BAX suffer from low throughput and static observations. To address this methodological gap, we developed FLAMBE, a kinetic fluorescence polarization-based assay to measure monomeric BAX activation in solution via concomitant displacement of a labeled peptide. This approach maintains the benefits of rapid kinetic data generation in a low-cost microplate format without requiring specialized equipment or large quantities of protein. FLAMBE compliments available experimental strategies and expands the accessibility of investigators to monitor early steps within the BAX activation continuum.

Physiological and pharmacological modulation of BAX

Bcl-2-associated X protein (BAX) is a critical executioner of mitochondrial regulated cell death through its lethal activity of permeabilizing the mitochondrial outer membrane (MOM). While the physiological function of BAX ensures tissue homeostasis, dysregulation of BAX leads to aberrant cell death. Despite BAX being a promising therapeutic target for human diseases, historically the development of drugs has focused on antiapoptotic BCL-2 proteins, due to challenges in elucidating the mechanism of BAX activation and identifying druggable surfaces of BAX. Here, we discuss recent studies that have provided structure-function insights and identified regulatory surfaces that control BAX activation. Moreover, we emphasize the development of small molecule orthosteric, allosteric, and oligomerization modulators that provide novel opportunities for biological investigation and progress towards drugging BAX.

The Bak core dimer focuses triacylglycerides in the membrane

Apoptosis, the intrinsic programmed cell death process, is mediated by the Bcl-2 family members Bak and Bax. Activation via formation of symmetric core dimers and oligomerization on the mitochondrial outer membrane (MOM) leads to permeabilization and cell death. Although this process is linked to the MOM, the role of the membrane in facilitating such pores is poorly understood. We recently described Bak core domain dimers, revealing lipid binding sites and an initial role of lipids in oligomerization. Here we describe simulations that identified localized clustering and interaction of triacylglycerides (TAGs) with a minimized Bak dimer construct. Coalescence of TAGs occurred beneath this Bak dimer, mitigating dimer-induced local membrane thinning and curvature in representative coarse-grain MOM and model membrane systems. Furthermore, the effects observed as a result of coarse-grain TAG cluster formation was concentration dependent, scaling from low physiological MOM concentrations to those found in other organelles. We find that increasing the TAG concentration in liposomes mimicking the MOM decreased the ability of activated Bak to permeabilize these liposomes. These results suggest that the presence of TAGs within a Bak-lipid membrane preserves membrane integrity and is associated with reduced membrane stress, suggesting a possible role of TAGs in Bak-mediated apoptosis.

Epigenetic toxicity and cytotoxicity of perfluorooctanoic acid and its effects on gene expression in embryonic mouse hypothalamus cells

Even though the endocrine-disrupting potential of perfluorooctanoic acid (PFOA) is well known, the mechanisms underlying its cellular and epigenetic toxicity at the critical stage of hypothalamic development are poorly understood. This is why we studied its effects on the embryonic mouse hypothalamic cell line N46 (mHypoE-N46) with a hope to shed more light on the mechanisms through which PFOA causes embryonic hypothalamic cell damage. To do that, we studied cell viability, global DNA methylation, and gene expression in cells exposed to PFOA. As the PFOA dose increased, cell viability decreased, while global DNA methylation increased. PFOA also significantly altered the expression of genes related to the apoptosis and cell cycle, neurotrophic genes, and the Tet, Dnmt, and Mecp2 genes. Our findings suggest that exposure to PFOA affects cell survival through the reprogramming of embryonic hypothalamic DNA methylation patterns and altering cell homeostasis genes. DNA methylation and changes in the Mecp2 gene expression induced by PFOA also imply wider ramifications, as they alter genes of other major mechanisms of the embryonic hypothalamus. Our study may therefore serve as a good starting point for further research into the mechanisms of PFOA effect of hypothalamic development.

The role of statins in lung cancer

Lung cancer is one of the most common causes of cancer-related mortality in the 21st century. Statins as inhibitors of 3-hydroxy-3-methylglutaryl coenzyme A reductase not only reduce the cholesterol levels in the blood and decrease the risk of cardiovascular disease but may also play an important role in the prevention and treatment of lung cancer. Statins have several antitumor properties including the ability to reduce cell proliferation and angiogenesis, decrease invasion and synergistic suppression of lung cancer progression. Statins induce tumor cell apoptosis by inhibition of downstream products such as small GTP-binding proteins, Rho, Ras and Rac, which are dependent on isoprenylation. Statins reduce angiogenesis in tumors by down-regulation of pro-angiogenic factors, such as vascular endothelial growth factor. In this review, the feasibility and efficacy of statins in the prevention and treatment of lung cancer are discussed.

SOX4 Serves an Oncogenic Role in the Tumourigenesis of Human Breast Adenocarcinoma by Promoting Cell Proliferation, Migration and Inhibiting Apoptosis

BACKGROUND

Breast cancer is among the most common malignant cancers worldwide, and breast adenocarcinoma in glandular tissue cells has excessive metastasis and invasion capability. However, little is known on the molecular process by which this disease develops and progresses.

OBJECTIVE

In this study, we explored the effects of sex-determining region Y-box 4 (SOX4) protein on proliferation, migration, apoptosis and tumourigenesis of breast adenocarcinoma and its possible mechanisms.

METHODS

The SOX4 overexpression or knockdown Michigan Cancer Foundation-7 (MCF-7) cell lines were established. Among the SOX4 overexpression or MCF-7 knockdown cell lines, proliferation, migration ability and apoptosis rate were detected. The expression levels of apoptosis-related proteins (Bax and Cleaved caspase-3) were analysed using Western blot. The effect of SOX4 on tumourigenesis was analysed using the clone formation assay in vitro and tumour xenograft experiment in nude mice.

RESULTS

Compared with the overexpression of control cells, proliferation and migration ability of SOX4 overexpression cells significantly increased, the apoptosis rate significantly decreased in addition to the expression levels of Bax and Cleaved caspase-3 (P < 0.05). Compared with the knockdown of control cells, proliferation and migration ability of SOX4 knockdown cells significantly decreased, and the apoptosis rate and expression levels of Bax and Cleaved caspase-3 significantly increased (P < 0.05). Clone formation and tumour growth abilities of SOX4 overexpression cells were significantly higher than those of the control cells (P < 0.05), whereas SOX4 knockdown cells had the opposite effect.

CONCLUSION

SOX4 plays an oncogenic role in breast adenocarcinoma tumourigenesis by promoting cell proliferation, migration and inhibiting apoptosis. It can be used as a potential molecular target for breast cancer gene therapy.

Linker Histone H1.2 Directly Activates BAK through the K/RVVKP Motif on the C-Terminal Domain

H1.2 is a key mediator of apoptosis following DNA double-strand breaks. The link between H1.2 and canonical apoptotic pathways is unclear. One study found that H1.2 stimulates cytochrome c (Cyt c) release; in contrast, apoptosis-inducing factor was found to be released in another study. The C-terminal domain (CTD) of H1.2 has been implicated in the latter pathway, but activation of the proapoptotic protein BCL-2 homologous antagonist/killer (BAK) is a common denominator in both pathways. This study aimed to determine whether the CTD of H1.2 is also responsible for mitochondrial Cyt c release and whether a previously identified K/RVVKP motif in the CTD mediates the response. This study investigated if H1.2 mediates apoptosis induction through direct interaction with BAK. We established that the CTD of H1.2 stimulates mitochondrial Cyt c release in vitro in a mitochondrial permeability transition-independent manner and that the substitution of a single valine with threonine in the K/RVVKP motif abolishes Cyt c release. Additionally, we showed that H1.2 directly interacts with BAK with weak affinity and that the CTD of H1.2 mediates this binding. Using two 20-amino acid peptides derived from the CTD of H1.2 and H1.1 (K/RVVKP motif inclusive), we determined the main residues involved in the direct interaction with BAK. We propose that H1.2 operates through the K/RVVKP motif by directly activating BAK through inter- and intramolecular interactions. These findings expand the view of H1.2 as a signal-transducing molecule that can activate apoptosis in a BAK-dependent manner.

Sphingolipid distribution at mitochondria-associated membranes (MAMs) upon induction of apoptosis

The levels and composition of sphingolipids and related metabolites are altered in aging and in common disorders such as diabetes and cancers, as well as in neurodegenerative, cardiovascular, and respiratory diseases. Changes in sphingolipids have been implicated as being an essential step in mitochondria-driven cell death. However, little is known about the precise sphingolipid composition and modulation in mitochondria or related organelles. Here, we used LC-MS/MS to analyze the presence of key components of the ceramide metabolic pathway in vivo and in vitro in purified ER, mitochondria-associated membranes (MAMs), and mitochondria. Specifically, we analyzed the sphingolipids in the three pathways that generate ceramide: sphinganine in the de novo ceramide pathway, SM in the breakdown pathway, and sphingosine in the salvage pathway. We observed sphingolipid profiles in mouse liver, mouse brain, and a human glioma cell line (U251). We analyzed the quantitative and qualitative changes of these sphingolipids during staurosporine-induced apoptosis in U251 cells. Ceramide (especially C16-ceramide) levels increased during early apoptosis possibly through a conversion from mitochondrial sphinganine and SM, but sphingosine and lactosyl- and glycosyl-ceramide levels were unaffected. We also found that ceramide generation is enhanced in mitochondria when SM levels are decreased in the MAM. This decrease was associated with an increase in acid sphingomyelinase activity in MAM. We conclude that meaningful sphingolipid modifications occur in MAM, the mitochondria, and the ER during the early steps of apoptosis.

miR-362 knock-down promotes proliferation and inhibits apoptosis in porcine immature Sertoli cells by targeting the RMI1 gene

Immature Sertoli cell proliferation determines the total number of mature Sertoli cells and further regulates normal spermatogenesis. Accumulating evidence demonstrates that microRNAs (miRNAs) play regulatory roles in immature Sertoli cell proliferation, while the functions and mechanisms of the Sertoli cells of domestic animals are poorly understood. In the present study, we aimed to investigate the roles of miR-362 in cell proliferation and apoptosis of porcine immature Sertoli cells. The results showed that miR-362 inhibition promoted the entrance of cells into the S phase and increased the expressions of cell cycle-related genes c-MYC, CNNE1, CCND1 and CDK4. Knock-down of miR-362 also promoted cell proliferation and inhibited apoptosis, which was demonstrated by the results from cell counting kit-8 (CCK-8), 5-ethynyl-2'-deoxyuridine (EdU) and Annexin V-FITC/PI staining assays. The recQ-mediated genome instability protein 1 (RMI1) gene was identified as a potential target gene of miR-362 via luciferase reporter assay, and miR-362 repressed the protein expression of RMI1 in porcine immature Sertoli cells. siRNA-induced RMI1 knock-down further abolished the effects of miR-362 inhibition on porcine immature Sertoli cells. Collectively, we concluded that miR-362 knock-down promotes proliferation and inhibits apoptosis in porcine immature Sertoli cells by targeting the RMI1 gene, which indicates that miR-362 determines the fate of immature Sertoli cells.

Long noncoding RNA KCNQ1OT1 promotes apoptosis in neuroblastoma cells by regulating miR-296-5p/Bax axis

Long noncoding RNAs (lncRNAs) are emerging as important regulators of multiple cellular processes such as cell invasion, growth, apoptosis and differentiation. LncRNAs can function as competing endogenous RNAs (ceRNAs) which sponge and sequester microRNA (miRNA) to regulate specific targets. Previously, we found that the target genes of several miRNAs, including FADD, Fas, Casp and Bax, are related to neuronal apoptosis and form a regulatory network. Among several factors, microRNA-296-5p expression was found to be negatively correlated with caspase activity and apoptosis. Here, we aimed to investigate the role of miR-296-5p in neuroblastoma (NB) cells. By performing quantitative real-time PCR (qRT-PCR), western blot and flow cytometry assays we analysed the expression of apoptotic markers in NB cells transfected with miR-296-5p mimics or inhibitor. Pathway-specific PCR array allowed us to identify the target genes of miR-296-5p. Using LncBase online tool, we predicted lncRNA KCNQ1 opposite strand/antisense transcript 1 (KCNQ1OT1) as an upstream regulator of miR-296-5p. The binding of KCNQ1OT1 and miR-296-5p was validated via RNA immunoprecipitation and Biotin pull-down assays. We also demonstrate that miR-296-5p suppresses apoptosis of NB cells in vitro and in vivo. Mechanistically, miR-296-5p directly bound the 3'UTR of Bax mRNA, thus repressing Bax at the mRNA and protein level. Moreover, through bioinformatic analysis and molecular experiments, we showed that KCNQ1OT1 sponged miR-296-5p and impaired its effect on NB cell apoptosis. In summary, KCNQ1OT1 is a potent promoting factor of cell apoptosis, which acts by sponging miR-296-5p and upregulating Bax. Our findings identify a regulatory axis of cell fate in NB cells.

Lipid-modulation of membrane insertion and refolding of the apoptotic inhibitor Bcl-xL

Bcl-xL is a member of the Bcl-2 family of apoptotic regulators, responsible for inhibiting the permeabilization of the mitochondrial outer membrane, and a promising anti-cancer target. Bcl-xL exists in the following conformations, each believed to play a role in the inhibition of apoptosis: (a) a soluble folded conformation, (b) a membrane-anchored (by its C-terminal α8 helix) form, which retains the same fold as in solution and (c) refolded membrane-inserted conformations, for which no structural data are available. Previous studies established that in the cell Bcl-xL exists in a dynamic equilibrium between soluble and membranous states, however, no direct evidence exists in support of either anchored or inserted conformation of the membranous state in vivo. In this in vitro study, we employed a combination of fluorescence and EPR spectroscopy to characterize structural features of the bilayer-inserted conformation of Bcl-xL and the lipid modulation of its membrane insertion transition. Our results indicate that the core hydrophobic helix α6 inserts into the bilayer without adopting a transmembrane orientation. This insertion disrupts the packing of Bcl-xL and releases the regulatory N-terminal BH4 domain (α1) from the rest of the protein structure. Our data demonstrate that both insertion and refolding of Bcl-xL are modulated by lipid composition, which brings the apparent pK_a of insertion to the threshold of physiological pH. We hypothesize that conformational rearrangements associated with the bilayer insertion of Bcl-xL result in its switching to a so-called non-canonical mode of apoptotic inhibition. Presented results suggest that the alteration in lipid composition before and during apoptosis can serve as an additional factor regulating the permeabilization of the mitochondrial outer membrane.

miR-26a inhibits proliferation and promotes apoptosis in porcine immature Sertoli cells by targeting the PAK2 gene

Accumulating reports have demonstrated that microRNAs (miRNAs) participate in regulating the complex processes of animal testis development and spermatogenesis; yet, the mechanisms by which miRNAs regulate spermatogenesis are poorly understood. miR-26a was identified as a miRNA that is differentially expressed among different pig testicular tissue developmental stages in our previous study. In this study, p21 activated kinase 2 (PAK2) gene was determined as one target gene of miR-26a by luciferase reporter assay, and miR-26a repressed the PAK2 mRNA abundance in porcine Sertoli cells. The Cell Counting Kit-8 (CCK8) assay, 5-Ethynyl-2'-deoxyuridine (EdU) assay and annexin V-FITC/PI staining assay results showed that miR-26a overexpression inhibited proliferation and promoted apoptosis in porcine Sertoli cells. These phenomena were similar to the siRNA-mediated knockdown of the PAK2 gene. Taken together, our results demonstrate that miR-26a inhibits proliferation and promotes apoptosis in porcine Sertoli cells by targeting the PAK2 gene, which may be a regulator of porcine spermatogenesis.

Chemical Probe to Identify the Cellular Targets of the Reactive Lipid Metabolite 2- trans-Hexadecenal

Lipid-derived electrophiles (LDEs) are reactive metabolites, which can covalently modify proteins and DNA and regulate diverse cellular processes. 2- trans-Hexadecenal (2-HD) is a byproduct of sphingolipid metabolism, involved in cytoskeletal reorganization, DNA damage, and apoptosis. In addition, the loss of ALDH3A2, an enzyme removing 2-HD in cells, is responsible for Sjörgen-Larsson Syndrome (SJS), suggesting that accumulation of 2-HD could lead to pathogenesis. However, the targets and the precise mechanisms of 2-HD are not well characterized. Herein, we report an alkyne-2-HD derivative as a bioorthogonal probe to explore the functions of 2-HD. We identified more than 500 potential cellular targets. Among them, the pro-apoptotic protein Bax can be covalently modified by 2-HD directly at the conserved Cys62 residue. Our work provided new chemical tools to explore the cellular functions of LDEs and revealed new mechanistic insights of the deregulation of lipid metabolism in diseases.

Decreased TRPM7 inhibits activities and induces apoptosis of bladder cancer cells via ERK1/2 pathway

Transient receptor potential melastatin 7 (TRPM7) functions as a Mg²⁺/Ca²⁺-permeable channel fused with a kinase domain and regulates various physical processes and diseases. However, its effects on pathogenesis of human bladder cancer (BCa) has not been clarified yet. Our microarray analysis has suggested that calcium signaling pathway is connected with bladder cancer via MAPK pathway. Therefore, we aim to investigate the mechanism of TRPM7 in BCa tumorigenesis by using BCa tissues compared with normal bladder epithelium tissues, as well as using distinct BCa cell lines (EJ, 5637 and T24). We observed increased TRPM7 expression and dysregulation of proteins involved in Epithelial-Mesenchymal Transition (EMT) in BCa tissues. Moreover, knockdown of TRPM7 in BCa cells reversed the EMT status, accompanied by increase of reactive oxygen species (ROS). Furthermore, TRPM7 deficiency could inhibit BCa cell proliferation, migration and invasion, as well as induce p-ERK1/2 and suppress PI3K/AKT at the protein level. Downregulation of TRPM7 promoted cell cycle arrest at G0/G1 phase and apoptosis in vitro, which could be recovered by pre-treatment with U0126 to deactivate ERK1/2, suggesting a close correlation between TRPM7 and the MAPK signaling pathway. Furthermore, a NOD/SCID mouse model transplanted using the BCa cells was established, revealing delayed tumor growth by reduced protein activity and mRNA transcription of TRPM7 in vivo. Our results suggested TRPM7 might be essential for BCa tumorigenesis by interfering BCa cell proliferation, motility and apoptosis.

Achyranthes bidentata polypeptide protects dopaminergic neurons from apoptosis in Parkinson's disease models both in vitro and in vivo

BACKGROUND AND PURPOSE

Parkinson's disease (PD) is a neurodegenerative disorder closely associated with dopaminergic neuron loss. It is well documented that Achyranthes bidentata polypeptides (ABPP) are potent neuroprotective agents in several kinds of neurons. Therefore, we proposed that ABPP might play a beneficial role against PD by protecting dopaminergic neurons from apoptosis.

EXPERIMENTAL APPROACH

SH-SY5Y cells and primary rat dopaminergic neurons were pretreated with ABPP fraction k (ABPPk), a purified fraction of ABPP, and then the cells were exposed to 1-methyl-4-phenylpyridinium iodide (MPP⁺ ) to induce apoptosis. Cell viability, LDH activity, a Tunel assay and protein levels of Bcl-2 and Bax were analysed. In an in vivo PD model induced by MPTP, ABPPk was intranasally delivered to mice. Behavioural tests, immunohistochemistry, immunostaining, Nissl staining, qRT-PCR and Western blot were employed to evaluate the potential effects of ABPPk on PD in mice.

KEY RESULTS

The application of ABPPk markedly enhanced the viability of SH-SY5Y cells and primary dopaminergic neurons treated with neurotoxic agent MPP⁺ . In an in vivo MPTP-induced PD model, ABPPk significantly improved behavioural performances and prevented tyrosine hydroxylase loss in the substantia nigra pars compacta and striatum. Furthermore, we showed that MPTP-induced astrocyte and microglia activation were largely attenuated by ABPPk, leading to low levels of neuroinflammation and a downregulation of the apoptotic signalling pathway.

CONCLUSION AND IMPLICATIONS

Taken together, our data show that ABPPk protects dopaminergic neurons from apoptosis, suggesting that ABPPk might be an effective intervention for treating the neuron loss associated with disorders such as PD.

Achyranthes bidentata polypeptide protects dopaminergic neurons from apoptosis induced by rotenone and 6-hydroxydopamine

It has been well documented that Achyranthes bidentata polypeptides (ABPPs) are potent neuroprotective agents in several types of neurons. However, whether ABPPs protect dopaminergic neurons from apoptosis induced by neurotoxins is still unknown. This study was designed to observe the effect of ABPPk, a purified fraction of ABPPs, on apoptosis of dopaminergic neurons. SH-5YHY cells and primary dopaminergic neurons were pre-treated with ABPPk (25, 50, or 100 ng/mL) for 12 hours. Cells were then exposed to 6-hydroxydopamine (50 or 150 μM) or rotenone (50 or 200 μM) for 36 hours to induce cell apoptosis. Our results demonstrate that ABPPk markedly increased viability in SH-SY5Y cells and primary dopaminergic neurons, decreased lactate dehydrogenase activity and number of apoptotic dopaminergic neurons, elevated mitochondrial membrane potential, and increased Bcl-2/Bax ratio. These findings suggest that ABPPk protects dopaminergic neurons from apoptosis, and that ABPPk treatment might be an effective intervention for treating dopaminergic neuronal loss associated with disorders such as Parkinson's disease.

Activin A induces apoptosis of mouse myeloma cells via the mitochondrial pathway

Activin A is a pleiotropic cytokine belonging to the transforming growth factor β superfamily. Abnormal expression of activin A is associated with tumorigenesis. Multiple myeloma is characterized by the development of osteolytic disease, which ultimately leads to cachexia. However, the involvement of activin A in myeloma cell viability and apoptosis remains to be fully elucidated. For this purpose, mouse myeloma NS-1 cells were treated with activin A, and subsequently subjected to 5-bromo-2'-deoxyuridine analysis, Hoechst 33342 staining, flow cytometry and western blot analysis. The results revealed that activin A significantly suppressed NS-1 cell viability, and induced NS-1 cell apoptosis. In addition, activin A-induced promotion of NS-1 cell apoptosis was accompanied by upregulated expression of BCL2 associated X, apoptosis regulator (Bax), but downregulated expression of B cell lymphoma-2 (Bcl-2), resulting in an increase of the Bax/Bcl-2 ratio. Furthermore, cytochrome c and caspase-3 protein expression also increased following treatment with activin A. These data suggest that activin A induces apoptosis in mouse myeloma NS-1 cells via the mitochondrial pathway, providing a novel insight into multiple myeloma treatment.

TM4SF1 regulates apoptosis, cell cycle and ROS metabolism via the PPARγ-SIRT1 feedback loop in human bladder cancer cells

Transmembrane-4-L-Six-Family-1 (TM4SF1) is a member of the L6 family and functions as a signal transducer to regulate cell development, growth and motility. Here we show that TM4SF1 is strongly upregulated in human muscle invasive bladder cancer (MIBC) tissues, corroborating the bioinformatical results of transcriptome analysis. Moreover, tissue microarray (TMA) shows significant correlations (p < 0.05) between high expression of TM4SF1 and T stage, TNM stage, lymph node metastasis status and survival rate of MIBC patients, indicating a positive association between TM4SF1 expression and poorer prognosis. Furthermore, in vitro and in vivo studies indicate that the proliferation of human bladder cancer (BCa) cells is significantly suppressed by knockdown of TM4SF1 (p < 0.05). Functionally, the reduction of TM4SF1 could induce cell cycle arrest and apoptosis possibly via the upregulation of reactive oxygen species (ROS) in BCa cells. In addition, these observations could be recovered by treatment with GW9662 (antagonist of PPARγ) and resveratrol (activator of SIRT1). Taken together, our results suggest that high expression of TM4SF1 predicts poor prognosis of MIBC.

Orchestrating Role of Apoptosis Inhibitor of Macrophage in the Resolution of Acute Lung Injury

Appropriate resolution of inflammation is known to be essential in tissue homeostasis. In this study, we evaluated the significance of a macrophage-derived soluble protein, apoptosis inhibitor of macrophage (AIM), in LPS-induced lung injury in mice. After oropharyngeal administration of LPS, the level of free-form serum AIM increased on days 2-4, accompanied by the resolution of inflammation, which was observed in the cellular profile of bronchoalveolar lavage fluid. In an experiment using wild-type (WT) and AIM^-/- mice, the resolution of inflammation was accelerated in AIM^-/- mice when compared with the WT mice, which was reversed when recombinant AIM protein was administered. The changes in the histopathological findings and inflammatory mediators followed similar trends, and the ratio of apoptotic cells was increased in AIM^-/- mice when compared with the WT mice. In vitro analysis showed that macrophage phagocytosis of apoptotic neutrophils was suppressed in the presence of AIM, indicating that anti-resolution property of AIM involves efferocytosis inhibition. In lipidomic analysis of lung tissues, the levels of several lipid mediators increased markedly when LPS was given to WT mice. However, in AIM^-/- mice, the concentrations of these lipid mediators were not significantly upregulated by LPS. These data reflect the significant role of AIM in lipid metabolism; it may suppress lipid metabolites at baseline, and then produce an inflammatory/pathologic pattern in the event of LPS-induced lung injury. Taken together, AIM may play an orchestrating role in the resolution process of inflammation by altering the profile of pulmonary lipid mediators in mice.

Ceramide-C16 Is a Versatile Modulator of Phosphatidylethanolamine Polymorphism

Ceramide-C16 (CerC16) is a sphingolipid associated with several diseases like diabetes, obesity, Parkinson disease, and certain types of cancers. As a consequence, research efforts are devoted to identify the impact of CerC16 on the behavior of membranes, and to understand how it is involved in these diseases. In this work, we investigated the impacts of CerC16 (up to 20 mol %) on the lipid polymorphism of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoethanolamine (POPE), using differential scanning calorimetry, and sequential ²H and ³¹P solid-state nuclear magnetic resonance spectroscopy. A partial phase diagram is proposed. The results indicate that the presence of CerC16 leads to an upshift of the temperature of the gel-to-liquid crystalline (L_β - L_α) phase transition, leading to a large L_β/L_α phase coexistence region where gel-phase domains contain ∼35 mol % CerC16. It also leads to a downshift of the temperature of the lamellar-to-inverted hexagonal (L - H_II) phase transition of POPE. The opposite influence on the two-phase transitions of POPE brings a three-phase coexistence line when the two transitions overlap. The resulting H_II phase can be ceramide enriched, coexisting with a L_α phase, or ceramide depleted, coexisting with a L_β phase, depending on the CerC16 proportions. The uncommon capability of CerC16 to modulate the membrane fluidity, its curvature propensity, and the membrane interface properties highlights its potential as a versatile messenger in cell membrane events.

Marsdeniae tenacissima extract-induced growth inhibition and apoptosis in hepatoma carcinoma cells is mediated through the p53/nuclear factor-κB signaling pathway

An extract from a traditional Chinese herb, Marsdeniae tenacissima (trade name, Xiao-Ai-Ping) has been approved for use on the Chinese market as a cancer chemotherapeutic agent for decades. Previous studies have demonstrated the cytostatic and pro-apoptotic effects of M. tenacissima extract (MTE) in multiple cancer cells. However, the contributions of MTE to the proliferation and apoptosis of hepatoma carcinoma cells and the underlying mechanisms remain unclear. In the present study, Bel-7402 cells were incubated with increasing concentrations of MTE ranging from 0–320 µl/ml to explore the effects and potential mechanisms of MTE on the proliferation and apoptosis of Bel-7402 cells. 3-(4,5-dimethylthiazol-2-yl)-5(3-carboxymethoxyphenyl)-2-(4-sulfopheny)-2H-tetrazolium, inner salt and propidium iodide (PI)-stained flow cytometry assays demonstrated that MTE significantly suppressed the proliferation of Bel-7402 cells in a dose-dependent manner by arresting the cell cycle at S phase (P<0.05). Annexin V-fluorescein isothiocyanate PI-stained flow cytometry confirmed the significantly pro-apoptotic effect of MTE at both 160 and 240 µl/ml (P<0.001). Reverse transcription-quantitative polymerase chain reaction and western blot analysis demonstrated that MTE (both 160 and 240 µl/ml) induced a significant downregulation of B-cell lymphoma (Bcl)-2 (P<0.01), upregulation of Bcl-2-associated X protein (P<0.01) and activation of caspase-3 (P<0.05). Furthermore, a significant downregulation of murine double minute-2 (MDM2) (P<0.001) and activation of p53 (P<0.001) in Bel-7402 cells following treatment with 160 or 240 µl/ml MTE was observed, accompanied by the inhibition of the nuclear factor (NF)-κB pathway (P<0.001). These results suggested that MTE inhibited growth and exhibited pro-apoptotic effects in Bel-7402 cells, which was mediated by downregulation of the MDM2-induced p53-dependent mitochondrial apoptosis pathway and blocking the NF-κB pathway. Overall, these data serve as preliminary identification of the significant roles of MTE in hepatic carcinoma cells, and suggest that MTE may be a promising candidate for hepatocellular carcinoma therapy.

Silencing of HJURP induces dysregulation of cell cycle and ROS metabolism in bladder cancer cells via PPARγ-SIRT1 feedback loop

Holliday Junction Recognition Protein (HJURP) is a centromeric histone chaperone involving in de novo histone H3 variant CenH3 (CENP-A) recruitment. Our transcriptome and in vivo study revealed that HJURP is significantly upregulated in bladder cancer (BCa) tissues at both mRNA and protein levels. Knockdown of HJURP inhibited proliferation and viability of BCa cell lines revealed by CCK-8, colony formation and Ki-67-staining assays, and induced apoptosis and reactive oxygen species (ROS) production, as well as triggered cell cycle arrest at G0/G1 phase possibly via loss of CENP-A. Interestingly, in the HJURP-reduced BCa cells the levels of PPARγ and acetylated-p53 were increased, while the ratio of phosphorylated/total SIRT1 protein was decreased. Moreover, after treatment of the BCa cells using PPARγ antagonist (GW9662) and SIRT1 agonist (resveratrol, RSV) respectively, thee phenotypes of cell cycle arrest, increased ROS production and inhibited proliferation rate were all rescued. Taken together, our results suggested that HJURP might regulate proliferation and apoptosis via the PPARγ-SIRT1 negative feedback loop in BCa cells.

Current Insights into Long Non-Coding RNAs (LncRNAs) in Prostate Cancer

The importance of long non-coding RNAs (lncRNAs) in the pathogenesis of various malignancies has been uncovered over the last few years. Their dysregulation often contributes to or is a result of tumour progression. In prostate cancer, the most common malignancy in men, lncRNAs can promote castration resistance, cell proliferation, invasion, and metastatic spread. Expression patterns of lncRNAs often change during tumour progression; their expression levels may constantly rise (e.g., HOX transcript antisense RNA, HOTAIR), or steadily decrease (e.g., downregulated RNA in cancer, DRAIC). In prostate cancer, lncRNAs likewise have diagnostic (e.g., prostate cancer antigen 3, PCA3), prognostic (e.g., second chromosome locus associated with prostate-1, SChLAP1), and predictive (e.g., metastasis-associated lung adenocarcinoma transcript-1, MALAT-1) functions. Considering their dynamic role in prostate cancer, lncRNAs may also serve as therapeutic targets, helping to prevent development of castration resistance, maintain stable disease, and prohibit metastatic spread.

RNAi-mediated knockdown of MCM7 gene on CML cells and its therapeutic potential for leukemia

MCM7 is one of the subunits of MCM2-7 complex, which is essential to DNA replication licensing and the control of cell cycle progression. It has been demonstrated that MCM7 participates in mRNA transcription and DNA damage regulation as well. MCM7 gene is found to be over-expressed in multiple cancers, but there are few reports about its effect in leukemia. Recent studies have proven that MCM7 expression has a relationship with diagnosis and prognosis, which has led to their potential clinical application as a marker for cancer screening. RNA interference (RNAi) is a biological process in which RNA molecules inhibit gene expression, typically by causing the destruction of specific mRNA molecules. It is a valuable research tool, which is widely used in cell culture and living organisms as well as in medicine recent years. It is indicated that RNAi application for targeting functional carcinogenic molecules, tumor resistance to chemotherapy and radiotherapy is required in cancer treatment. Gene products knockdown by RNAi technology exerts anti-proliferative and pro-apoptotic effects upon cell culture systems, animal models and in clinical trials in the most studies. In the present study, we found that MCM7 highly expressed in K562 cells rather than that in normal neutrophils. Thus, lentivirus-mediated shRNA targeting MCM7 was used to suppress its endogenous expression in K562 cells and develop a novel therapeutic strategy for leukemia.

Enhanced therapeutic efficacy of LHRHa-targeted brucea javanica oil liposomes for ovarian cancer

Background

Although brucea javanica oil liposomes (BJOLs) have been used clinically to treat ovarian cancer, its clinical efficacy is often limited by systemic side effects due to non-specific distribution. Luteinizing hormone releasing hormone receptor (LHRHR) is overexpressed in most ovarian cancers but negligibly expressed in most of the other visceral organs. In this study, we aimed to develop a novel LHRHa targeted and BJO-loaded liposomes (LHRHa-BJOLs), and investigate its characteristics, targeting ability and anti-ovarian cancer efficiency both in vitro and in vivo.

Methods

The LHRHa-BJOLs were prepared by film-dispersion and biotin-streptavidin linkage methods, and characterized in terms of its morphology, particle size, zeta potential, ligand conjugation, encapsulation efficiency and stability. The targeting nature and antitumor effects of the liposomes were evaluated in vitro using cultured human ovarian cancer A2780/DDP cells, and in vivo using ovarian cancer-bearing nude mice.

Results

The LHRHa-BJOLs were successfully synthesized, with a uniformly spherical shape, appropriate particle size and zeta potential, as well as a high encapsulation efficiency. Compared to non-targeted liposomes and BJO emulsion, the LHRHa-BJOLs could significantly increase specific intracellular uptaking rate, enhance cell inhibitory effect and induce cell apoptosis in A2780/DDP cells in vitro. Meanwhile, LHRHa-BJOLs also had a significantly stronger activity of targeting tumor tissue, inhibiting tumor growth, inducing tumor apoptosis and prolonging survival time in ovarian cancer-bearing mice in vivo.

Conclusions

Our experiment suggests that LHRHa-BJOLs may be a useful targeted drug for the treatment of ovarian cancer.

Hyperlipidemia and the development of diabetic retinopathy: Comparison between type 1 and type 2 animal models

AIM

In the pathogenesis of diabetic retinopathy, reactive oxygen species (ROS) are elevated in the retina and the mitochondria are damaged, resulting in accelerated apoptosis. Dyslipidemia is also considered as one of the major factors in its development, and our aim is to investigate the compounding effect of hyperlipidemia in retinopathy.

METHODS

Retinal ROS, mitochondrial damage and vascular pathology were investigated in Zucker diabetic fatty rats (ZDF, type 2 diabetes model), during the age that spans from hyperlipidemia/pre-hyperglycemia (6weeks), to severe hyperglycemia/moderate hyperlipidemia (~12weeks), and ultimately to severe hyperglycemia/hyperlipidemia (20-40weeks). For comparison, retina from streptozotocin-induced Wistar rats (type 1 diabetic for 10-40weeks) was analyzed.

RESULTS

Compared to age-matched lean rats, despite increased retinal cytosolic ROS in 6-week-old ZDF rats, mitochondrial dysfunction and DNA damage were not detected, and in 12-week-old ZDF rats, retinal mitochondria were dysfunctional, but mtDNA damage and vascular pathology (cell apoptosis and degenerative capillaries) were not detectable. Retina from 20-week-old ZDF rats (hyperglycemic for 14weeks or less) had significant mitochondrial dysfunction, mtDNA damage and vascular pathology, and similar abnormalities were observed in 40-week-old ZDF rats. Although retinal mitochondrial dysfunction was observed in Wistar rats diabetic for 20weeks, mtDNA damage and vascular pathology were not detectable till the duration of diabetes was further extended.

CONCLUSIONS

Hyperlipidemia, in a hyperglycemic milieu, potentiates mitochondrial damage and augments the development of retinopathy. Control of dyslipidemia in pre-diabetic patients may prevent/delay the development and the progression of this devastating disease.

Prostate tumor attenuation in the nu/nu murine model due to anti-sarcosine antibodies in folate-targeted liposomes

Herein, we describe the preparation of liposomes with folate-targeting properties for the encapsulation of anti-sarcosine antibodies (antisarAbs@LIP) and sarcosine (sar@LIP). The competitive inhibitory effects of exogenously added folic acid supported the role of folate targeting in liposome internalization. We examined the effects of repeated administration on mice PC-3 xenografts. Sar@LIP treatment significantly increased tumor volume and weight compared to controls treated with empty liposomes. Moreover, antisarAbs@LIP administration exhibited a mild antitumor effect. We also identified differences in gene expression patterns post-treatment. Furthermore, Sar@LIP treatment resulted in decreased amounts of tumor zinc ions and total metallothioneins. Examination of the spatial distribution across the tumor sections revealed a sarcosine-related decline of the MT1X isoform within the marginal regions but an elevation after antisarAbs@LIP administration. Our exploratory results demonstrate the importance of sarcosine as an oncometabolite in PCa. Moreover, we have shown that sarcosine can be a potential target for anticancer strategies in management of PCa.