Review on marine collagen peptides induce cancer cell apoptosis,necrosis, and autophagy by reducing oxidized free radicals

Marine collagen peptides (MCPs) are natural products prepared by hydrolyzing marine collagen protein through a variety of chemical methods or enzymes. MCPs have a range of structures and biological activities and are widely present in marine species. MCPs also have a small molecular weight, are easily modified, and absorbed by the body. These properties have attracted great interest from researchers studying antioxidant, anti-tumor, and anti-aging activities. MCPs of specific molecular weights have significant anti-tumor activity and no toxic side effects. Thus, MCPs have the potential use as anti-cancer adjuvant drugs. Free radicals produced by oxidation are closely related to human aging, cancer, arteriosclerosis, and other diseases, but their relationship with cancer is not well known. In this review, we focus on the antioxidant properties of MCPs in the treatment of cancer, highlighting their antioxidant molecular structure and potential for clinical practice.     

Vitamin B3 inhibits apoptosis and promotes autophagy of islet β cells under high glucose stress

Background: Hyperglycemia is a typical symptom of diabetes. High glucose induces apoptosis of islet β cells. While autophagy functions in cytoprotection and autophagic cell death. The interaction between autophagy and apoptosis is important in the modulation of the function of islet β cells. Vitamin B3 can induce autophagy and inhibit islet β apoptosis.Method: The mechanism of vitamin B3-mediated protective effect on the function of islet β cells was explored by the method of western blot, immunofluorescence and flow cytometry.Results: In the present study, high glucose stress increased the apoptosis rate, while vitamin B3 reduced the apoptosis rate. The effect of vitamin B3 on autophagy flux under normal and high glucose stress was also investigated. Vitamin B3 increased the number of autophagosomes and increased the light chain (LC)3-II/LC3-I ratio. In contrast, vitamin B3 decreased sequestosome 1 (SQSTM1)/p62 protein expression and inhibited the phosphorylation of mammalian ribosomal protein S6 kinase β-1 (p70S6K/S6K1), which was a substrate of mammalian target of rapamycin (mTOR) under normal and high glucose stress. To further verify the protective effect of vitamin B3 on apoptosis, we treated islet β cell RIN-m5F with autophagy inhibitor 3-methyladenine (3-MA). Vitamin B3 decreased the apoptosis rate under high glucose stress, while the inhibition of apoptosis by vitamin B3 was blocked after adding 3-MA.Conclusion: Our data suggested that vitamin B3 reduced the apoptosis rate of β cells, possibly through inducing autophagy under high glucose stress.     

Hyperbaric oxygen protects against PC12 and H9C2 cell damage caused by oxygen–glucose deprivation/reperfusion via the inhibition of cell apoptosis and autophagy

In this study, we investigated the protective effect of hyperbaric oxygen (HBO) on PC12 and H9C2 cell damage caused by oxygen-glucose deprivation/reperfusion and its possible mechanism. PC12 and H9C2 cell oxygen-glucose deprivation/reperfusion model were established. Cells were divided into a control group, model group, hyperbaric air (HBA) group and HBO group. The cell viability was detected by the CCK8 assay. Hoechst 33342 and PI staining assays and mitochondrial membrane potential (MMP) assays were used to detect cell apoptosis. The ultrastructure of cells, including autophagosomes, lysosomes, and apoptosis, were examined using a transmission electron microscope. The expression of autophagy-related proteins was detected by cellular immunofluorescence and immunocytochemistry. Our results showed that HBO can significantly improve the vitality of damaged PC12 and H9C2 cells caused by oxygen–glucose deprivation/reperfusion. HBO can significantly inhibit apoptosis of PC12 and H9C2 cells caused by oxygen-glucose deprivation/reperfusion. Importantly, we found that the protective mechanism of PC12 and H9C2 cell damage caused by oxygen-glucose deprivation/reperfusion may be related to the inhibition of the autophagy pathway. In this study, the results of cellular immunofluorescence and immunocytochemistry experiments showed that the 4E-BP1, p-AKt and mTOR levels of PC12 and H9C2 cells in the model group decreased, while the levels of LC3B, Atg5 and p53 increased. However, after HBO treatment, these autophagy-related indexes were reversed. In addition, observation of the cell ultrastructure with transmission electron microscopy found that in the model group, a significant increase in the number of autophagic vesicles was observed. In the HBO group, a decrease in autophagic vesicles was observed. The study demonstrated that hyperbaric oxygen protects against PC12 and H9C2 cell damage caused by oxygen-glucose deprivation/reperfusion via the inhibition of cell apoptosis and autophagy.     

Application of confocal scanning laser microscopy in experimental pathology

Confocal scanning laser microscopy (CSLM) represents an exciting new tool for scientific disciplines which focus on mechanistic studies such as experimental pathology. Enhanced resolution in the specimen plane and rejection of out-of-focus fluorescence flare allow analysis of specific nucleic acid sequences, enzymes, structural macromolecules, and cellular homeostasis utilizing fluorescent probes. Four different experimental applications are discussed which utilize CSLM to evaluate pathological processes at the subcellular, cellular, and tissue levels. Programmed cell death, or apoptosis, is a natural process of significance both during development and as a response to toxic stimuli. CSLM-imaging of nuclei of human B lymphoblastoid cells following exposure to a monofunctional alkylating agent suggests that the degradation of chromatin characteristic of apoptosis may occur in asymmetric patterns. Surfactant apoprotein-A is the major non-serum protein component of pulmonary surfactant and is essential for the extracellular function of surfactant. CSLM of alveolar type II cells suggests that apoprotein-A is present in both the cytoplasm, predominantly in lamellar bodies, and in the nucleus. The tumor promoter, phorbol myristate acetate, rapidly stimulated the formation of vacuoles in human neutrophils. CSLM using Lucifer Yellow as a probe suggests that cylindrical vacuoles are formed by fluid-phase pinocytosis. The blood-nerve barrier (BNB) in peripheral nerves may be an important target during toxin-induced neuropathies. Ricin-induced permeability of the BNB in the rat was rapidly visualized by CSLM as leakage of fluorescein isothiocynate (FITC)-dextran into the endoneurial compartment.     

The antitumor effects of Newcastle disease virus on glioma

Glioma is the most common primary malignant brain tumor with a poor survival rate. In recent years, no significant progress has been made in the treatment of gliomas in contrast to the development of improved diagnosis via molecular typing. Newcastle disease virus (NDV), a negative-stranded RNA virus that exhibits oncolytic activity, has been investigated for its capacity to elicit antitumor activity in many types of cancers, including glioma. Therefore, application of oncolytic viruses, such as NDV, as a new treatment strategy to specifically target aberrant signaling in glioblastomas has brought new hope. For many years, NDV has been investigated for its in vivo and in vitro efficacy in the treatment of various tumor cells. Based on its safety in humans, specificity for tumor cells, and immunostimulatory properties, NDV represents a promising antitumor agent. In this review, we summarize the background of NDV and the antitumor mechanisms of NDV-mediated oncolysis, discuss the potential value and role of NDV in gliomas, and describe new advances and perspectives for future research.     

Capsaicin exerts anti-benign prostatic hyperplasia effects via inhibiting androgen receptor signaling pathway

Background: Benign prostatic hyperplasia (BPH) is a common condition in middle-aged and elderly men. Enlargement of the prostate causes lower urinary tract symptoms. Capsaicin is a phytochemical extracted from chili peppers and exerts many pharmacological actions, such as anti-tumor and anti-inflammatory effects. Methods: Our study investigated the effect of capsaicin in vitro and in a mouse model in vivo. A prostatic stromal myofibroblast cell line (WPMY-1) was co-incubated with testosterone (1 µM) and different concentrations of capsaicin (10–100 µM) for 24 and 48 h. Capsaicin (10–100 µM) significantly inhibited testosterone-treated WPMY-1 cell growth at 48 h by MTT assay. The testosterone propionate (7.5 mg/kg)-induced BPH mouse model was used to examine the anti-proliferative effect of capsaicin. Treatment with capsaicin (10 mg/kg) for 14 days significantly attenuated prostatic hyperplasia. Finasteride was used as a positive control. Results: Capsaicin significantly decreased prostate weight and prostate index (prostate/body weight ratio) in BPH mice. The expression of 5α-reductase type II, androgen receptor (AR) and prostate specific antigen (PSA) protein expression and PSA serum were all significantly reduced in capsaicin-treated BPH mice. In addition, capsaicin also activated transient receptor potential vanilloid 1 mediated apoptosis and autophagy in BPH mice. Conclusion: These results demonstrate multiple positive effects of capsaicin in controlling prostate growth and suggest its therapeutic potential in the treatment of BPH.     

Hypoxia induced apoptosis of rat gastric mucosal cells by activating autophagy through HIF-1α/TERT/mTORC1 pathway

The pathogenesis of high altitude-related gastric mucosal injury remains poorly understood, this study aimed to investigate the role of autophagy in hypoxia-induced apoptosis of rat gastric mucosal cells. Rats were randomized into four groups which were maintained at an altitude of 400 m (P) or received no treatment (H), autophagy inducer rapamycin (H+AI) or autophagy inhibitor 3-MA (H+AB) at an altitude of 4,300 m for 1, 7, 14 and 21 days, respectively, and the morphology, ultrastructure, autophagy, and apoptosis of gastric mucosal tissues were examined. Gastric mucosal epithelial cells CC-R039 were cultured under conditions of normoxia, 2% O2 (hypoxia), or 2% O2+anti-mTORC1 for 0, 24, 48, and 72 h, respectively, and the autophagy and apoptosis were analyzed. CC-R039 cells were transfected with siHIF-1α, siTERT, or siRNA and the autophagy was examined. The results showed that the exposure to hypoxia increased the autophagy and apoptosis of gastric mucosal cells in rats, and apoptosis was aggravated by rapamycin treatment but alleviated by 3-MA treatment. Increased duration of hypoxia from 0 to 72 h could increase the autophagy and apoptosis but decrease the proliferation of gastric mucosal cells. Inhibition of mTORC1 with rapamycin led to further increase in apoptosis and even substantial cell death, and inhibition of HIF- 1α and TERT increased mTORC1 expression and reduced autophagy. Moreover, the inhibition of HIF-1α reduced TERT expression. In conclusion, hypoxia could induce apoptosis of rat gastric mucosal cells by activating autophagy through HIF-1α/TERT/mTORC1 pathway     

Role of granulosa and theca cell interactions in ovarian follicular maturation

We developed a culture system in which two types of ovarian follicular cells were allowed to attach to opposite sides of a collagen membrane. Using this in vitro cell culture system, we studied the effects of granulosa- and theca-cell interaction on the morphology, structure, and function of bovine ovarian follicular cells. In the first part of the study, we explored how the interaction between theca and granulosa cells affects the morphology and structure of the cells. This study was done using follicular cells collected from bovine ovarian follicles at the early developmental stage. Granulosa cells cultured alone were flattened, and formed a monolayer sheet. By contrast, granulosa cells cultured with theca cells were convex, and formed multilayer sheets. Theca cells cultured alone were thin, flat, and spindle-shaped. Theca cells cultured with granulosa cells were also spindle-shaped; however, they appeared convex and more densely packed when compared with theca cells cultured alone. In the second part of the study, the possible role of the cellular interaction in the control of differentiation and growth of granulosa and theca cells was investigated. When follicular cells were isolated from the early stage of follicular development, theca cells reduced progesterone and inhibin production by granulosa cells and augmented the growth of granulosa cells. When the cells were isolated from the late stage of follicular development, by contrast, theca cells augmented hormonal production by granulosa cells, and did not affect the growth of granulosa cells. The growth and androstenedione production by theca cells were increased by the presence of granulosa cells, irrespective of the origin of follicular cells. These results demonstrated that communication between two types of follicular cells results in reciprocal modulation of their morphology, structure, growth, and function. Cellular interactions seem to be one of the major factors controlling the differentiation and growth of the follicular cells during the follicular maturation process. In contrast to granulosa and theca cells cultured alone, cells in the coculture seemed to possess morphological and functional characteristics more similar to those of cells in the growing follicular wall in vivo. Thus, we speculate that the interaction between these two types of follicular cells is essential for the maintenance of original structure and function of the bovine follicular wall.     

An in vitro study to explore the role of prolylcarboxypeptidase in non-small cell lung cancer

Prolylcarboxypeptidase (PRCP) belongs to the S28 family of proteases, which is also a dipeptidyl peptidase. In this study, we demonstrate the expression pattern of PRCP in Non-small cell lung cancer (NSCLC). We found that the repression of PRCP expression by small interfering RNA successfully inhibited cell proliferation, migration, and invasion. Further, we explored the involvement of PRCP in the regulation of epithelial-mesenchymal transition (EMT). The epithelial marker E-cadherin was significantly increased, meanwhile mesenchymal markers MUC1, vimentin, and SNAIL were markedly decreased in PRCP knockdown cells. Moreover, the downregulation of PRCP in the NSCLC cells induced the expression of apoptosis-related proteins in vitro. We performed RT-PCR in 30 pairs of clinical NSCLC tissues and adjacent non-cancerous tissues, which revealed significantly higher PRCP expression levels in cancer tissues than in adjacent non-cancerous tissues. Collectively the results from our study suggest a possible cancer promotion role of PRCP in NSCLC.     

KRT4 suppresses oral squamous cell carcinoma development by reducing ATG4B-mediated autophagy

Head and neck squamous cell carcinoma is the sixth most common tumor worldwide, and half of head and neck squamous cell carcinoma patients are with oral squamous cell carcinoma (OSCC). 300,000 new cases of OSCC were reported annually. Even with multi-modality treatment, the prognosis of OSCC remains unsatisfactory. Thus, it is urgent to discover novel therapeutic targets for OSCC. Some microarray studies have revealed that Keratin 4 (KRT4) is downregulated in OSCC, whereas its role in OSCC development remains unknown. The present study revealed that KRT4 suppressed OSCC progression by inducing cell apoptosis and inhibiting cell invasion. In addition, KRT4 over-expression inhibited autophagy by blocking the interaction of autophagy-related 4B cysteine peptidase (ATG4B) and microtubule-associated protein 1A/1B light chain 3 (LC3) to regulate apoptosis and invasion of OSCC. In conclusion, KRT4 played an important role in OSCC development through regulating ATG4B-mediated autophagy and may be a novel therapeutic drug target of OSCC.     

Dual-color fluorescence lifetime correlation spectroscopy to quantify protein-protein interactions in live cell

Dual-color fluorescence correlation spectroscopy is an interesting method to quantify protein interaction in living cells. But, when performing these experiments, one must compensate for a known spectral bleed through artifact that corrupts cross-correlation data. In this article, problems with crosstalk were overcome with an approach based on fluorescence lifetime correlation spectroscopy (FLCS). We show that FLCS applied to dual-color EGFP and mCherry cross-correlation allows the determination of protein-protein interactions in living cells without the need of spectral bleed through calibration. The methodology was validated by using EGFP-mCherry tandem in comparison with coexpressed EGFP and mCherry in live cell. The dual-color FLCS experimental procedure where the different laser intensities do not have to be controlled during experiment is really very helpful to study quantitatively protein interactions in live sample.     

Fine structure and function of kupffer cells

Kupffer cells are macrophages that are attached to the luminal surface or inserted in the endothelial lining of hepatic sinusoids. In this site, Kupffer cells play a key role in host defense by removing foreign, toxic and infective substances from the portal blood and by releasing beneficial mediators. Under some conditions, toxic and vasoactive substances also are released from Kupffer cells which are thought to play a role in a variety of liver diseases. Many of these activities may be modulated by the levels of gut derived endotoxin normally present in the portal blood. The ultrastructural aspects of Kupffer cell structure function in situ are best studied using perfused-fixed livers. In fixed livers, transmission and scanning electron microscopy reveal Kupffer cells during health to be irregular in shape with their exposed surfaces presenting numerous microvilli, filopodia, and lamellopodia. Long filopodia penetrate endothelial fenestrae to secure Kupffer cells to the sinusoid lining. Specific membrane invaginations known as worm-like bodies or vermiform processes are seen in the cytoplasm of Kupffer cells as are numerous endocytotic vesicles and lysosomes which vary in density, shape and size. Sometimes, annulate lamellae connected to the rough endoplasmic reticulum also are found. The principal endocytic mechanisms of Kupffer cells are phagocytosis of particulates and cells, and bristle-coated micropinocytosis for fluid-phase endocytosis of smaller substances. Many of these events are mediated by specific receptors. In some species, Kupffer cells can be distinguished from other sinusoidal lining cells and monocytes by specific cytoplasmic staining or monoclonal antibodies. Kupffer cells have been shown to be of monocytic origin as well as having the capacity for self-replication.     

Having a swell time--mitochondrial morphology and plant cell death programmes

Cell death is a vital process in multi-cellular eukaryotes. Rather than being a contradiction in terms, this statement highlights the importance of limited and localized cell killing to the health and normal development of complex organisms. The main focus of this article is the role of mitochondrial morphological changes during cell death programmes, and the conserved role of mitochondrial permeability transition (increased permeability of either the outer or inner membrane) as an early mechanistic event preceding cell death in both plant and non-plant eukaryotes. A second focus of this article is a review of the terminology and fundamental paradigms underpinning cell death research. Because of the importance of the process of cell death, there has been an enormous quantity of research performed to try to understand the underlying biological mechanisms. One result of such a large and varied research effort, and a result that is perhaps particularly evident to investigators coming into the field anew, is that some of the basic tenets of cell death research appear to have become confused. In this short article, I make an attempt to clarify the subject, focussing on the role of mitochondria, and the difficulties in comprehensibility arising from the sometimes-erroneous, or at least unnecessarily confusing use of specific terminology; there are several key terms in the cell death literature that appear interchangeable when they are not, or are interchanged when they should not be.     

Alveolar macrophage-T cell interactions during Th1-type sarcoid inflammation

Sarcoidosis is an immunomediated, multisystem disorder of unknown cause(s) characterized by a heightened Th1 immune response that leads to an uncontrolled granuloma formation at sites of disease activity. The past few years have seen outstanding advances in the understanding of immunological and molecular events involved in the pathogenesis of this disease. The idea is that several cytokines and chemokines, which are secreted at sites of disease activity, participate in granuloma formation. This paper describes recent data that have clarified some of the events that govern the development of the hypersensitivity reaction during sarcoidosis. In particular, we will review recent evidence indicating that a complex relationship exists between the macrophage/lymphocyte cellular axis and the tissue networks of cytokines.     

Interference microscopic studies on wood plastic and cell wall—liquid interactions in beech

A method is described to measure the content of methylmethacrylate-polymer (poly-MMA) in wood-plastic composites and the influence of MMA on water and ethanol accessibility of beech wood fibre walls using interference microscopy. Although the S₂-layer of the fibre wall is capable of containing about 12% volume of plastic, the effect of treatment on ultimate water absorption of the cell wall is negligible. The ultimate absorption of ethanol is, however, completely reduced to zero. Increased dimensional stability of wood-poly-MMA composites is probably due to hindrance by the plastic in the lumina of the wood elements. The interference microscopic method is also shown to be suitable for determination of the fibre saturation point of cell wall areas.     

Raloxifene-loaded and aptamer-bonded exosomes induce autophagic and apoptotic death in HeLa cells by enhancing the lysosomotropic effect

Background: Raloxifene, a selective estrogen receptor modulator, is also known to be a lysosomotropic agent. The bioavailability of raloxifene is around 2% due to extensive hepatic transport. Exosomes are nanosized vesicles that are naturally released from cells. Method: In this study, exosomes released from HeLa cervical cancer cells were loaded with raloxifene to increase its bioavailability, and an aptamer was attached to the exosome membrane for targeting only HeLa cells. Characterization of exosomes isolated from HeLa cells was performed by transmission electron microscopy, zeta sizer, and western blotting. In addition, the cytotoxic, apoptotic, autophagic, and lysosomotropic effects of the prepared Exo-Apt-Ral formulation on HeLa cervical cancer cells were investigated. Results: According to zeta analysis, the sizes of the empty exosome and Exo-Apt-Ral formulation were measured as 66 ± 12 and 120 ± 21 nm, respectively. There was a rise in the lysosomal permeability of HeLa cells after the Exo-Apt-Ral application. In addition, both apoptotic and autophagic death mechanisms were triggered in HeLa cells after the Exo-Apt-Ral application. Conclusion: This study showed that raloxifene functionalized by loading into aptamer-bound exosomes can be a new targeted drug carrier system for cervical cancer.     

Regulatory cell interactions between retinal ganglion cells and radial glia during axonal and dendritic outgrowth

Neuronal differentiation and the formation of cell polarity are crucial events during the development of the nervous system. Cell polarity is a prerequisite for directed information flux within neuronal networks. In this article, we focus on neuro-glial cell interactions that influence the establishment of neural cell polarity and the directed outgrowth of axons versus dendrites. The cellular model discussed in detail is the retinal ganglion cell (RGC) of the chick retina, which is investigated by a comprehensive set of in vitro assays. The experiments demonstrate that retinal microenvironment determines axon vs. dendrite formation of RGCs. The instructive differences in different retinal microenvironments are substantially influenced by radial glia. Different glial domains support or inhibit axon vs. dendrite outgrowth. The data support the notion that neuro-glial interactions are crucial for directed neurite outgrowth.     

Probing molecular interactions and mechanical properties of microbial cell surfaces by atomic force microscopy

Knowledge of the surface properties of microbial cells is a key to gain a detailed understanding of their functions in the natural environment and to efficiently exploit them in biotechnological processes. In this paper, we present force-distance curves recorded, by atomic force microscopy (AFM) in aqueous solutions, on various microbial samples: reconstituted S-layers, whole fungal spores and several bacterial strains. The approach and retraction curves exhibited important differences--depending on the type of microorganism, on the physiological state (dormancy versus germination) and on the environmental conditions (ionic strength)--which were shown to reflect differences in long-range surface forces, adhesion forces and mechanical properties. These data illustrate the great potential of AFM force measurements to elucidate the physical properties of microbial cells and to understand, at the molecular level, biointerfacial phenomena such as cell adhesion and cell aggregation.     

Lysosomal movements during heterophagy and autophagy: With special reference to nematolysosome and wrapping lysosome

Recent studies on lysosomal movements during heterophagy and autophagy performed in our laboratory for the past several years were reviewed; methods for the investigation of lysosomes and the cytoskeleton in these studies mainly involved electron microscopic cytochemistry. Lysosomal movements during heterophagy were observed in cultured rat alveolar macrophages taking up horseradish peroxidase (HRP) and rat peroxidase-antiperoxidase (PAP) by fluid-phase pinocytosis and adsorptive pinocytosis, respectively. A characteristic lysosomal change which was induced by the pinocytosis was the appearance of long, threadlike lysosomes (nematolysosomes) in the cytoplasm. The effects of actin filament destabilizer and antimicrotubular drug on lysosomal changes revealed that the appearance of nematolysosomes was dependent on the presence of both actin filaments and microtubules. The close morphological relationship between lysosomes and cytoskeletal elements, such as actin filaments and microtubules in the alveolar macrophages, supports the participation of the cytoskeletal system in the regulatory mechanism of lysosomal movements. In the study of the lysosomal wrapping mechanism (LWM), which is one type of lysosomal movement that occurs during autophagy, it was found that the occurrence of LWM was dependent on energy—namely, the supply of ATP—and on the presence of actin filaments. However, deconstruction of microtubules induced or favored the occurrence of LWM. It is conceivable that the LWM is also related to the cytoskeletal system. We conclude that intracellular dynamics of lysosomes during heterophagy and autophagy are largely a consequence of complicated modulation by the cytoskeletal system.