Cell survival and apoptosis signaling as therapeutic target for cancer: marine bioactive compounds. Int J Mol Sci. 2013;14:2334-2354. [PMID: 23348928 PMCID: PMC3587990 DOI: 10.3390/ijms14022334]

Induction of Apoptosis and Inhibition of Epithelial Mesenchymal Transition by α-Mangostin in MG-63 Cell Lines

Osteosarcoma is the most common bone primary malignant tumor and nearly 30% of patients still die from osteosarcoma due to metastasis or recurrence. Thus, it is necessary to develop effective new chemotherapeutic agents for osteosarcoma treatment. α-Mangostin is a xanthone derivative shown to have antioxidant and anticarcinogen properties. However, the molecular mechanisms underlying the antimetastatic effects of osteosarcoma remain unclear. In metastasis progression, epithelial mesenchymal transition (EMT) is a process that plays important roles in development, cell polarity, and increased invasion and migration. This study focused on the induction of apoptosis and inhibition of EMT process by α-mangostin in human osteosarcoma cell line MG63. α-Mangostin treatments on MG63 cells not only showed the several lines of evidence of apoptotic cell death but also inhibited cell migration, invasion, and EMT-inducing transcription factor. In conclusion, we demonstrate that the α-mangostin induces apoptosis via mitochondrial pathway and suppresses metastasis of osteosarcoma cells by inhibiting EMT.

Dual Roles of Serine-Threonine Kinase Receptor-Associated Protein (STRAP) in Redox-Sensitive Signaling Pathways Related to Cancer Development

Serine-threonine kinase receptor-associated protein (STRAP) is a transforming growth factor β (TGF-β) receptor-interacting protein that has been implicated in both cell proliferation and cell death in response to various stresses. However, the precise roles of STRAP in these cellular processes are still unclear. The mechanisms by which STRAP controls both cell proliferation and cell death are now beginning to be unraveled. In addition to its biological roles, this review also focuses on the dual functions of STRAP in cancers displaying redox dysregulation, where it can behave as a tumor suppressor or an oncogene (i.e., it can either inhibit or promote tumor formation), depending on the cellular context. Further studies are needed to define the functions of STRAP and the redox-sensitive intracellular signaling pathways that enhance either cell proliferation or cell death in human cancer tissues, which may help in the development of effective treatments for cancer.

The tumor antagonistic steroidal alkaloid Solanidine prompts the intrinsic suicidal signal mediated DFF-40 nuclear import and nucleosomal disruption

Aim Deformity in the cellular homeostatic event associated with cell survival and apoptosis are committing factors for carcinogenesis. Interventions of these events by pharmacologically active agent gain predominance in cancer treatment. In current investigation Solanidine, a steroidal alkaloid was evaluated on tumorigenesis by targeting death signal using multiple tumor cells and model systems.

MAIN METHODS

Anti-proliferative effect was evaluated using cytotoxic studies. Prolonged cytotoxic effect of Solanidine was examined by colony formation assay. Exhibition of apoptotic hallmark induced by Solanidine was examined using FACS analysis, Annexin-V staining, Acridine orange staining, TUNEL assay. Altered gene expression was evaluated using Immunoblot, Immunofluorescence and Immunohistochemistry technique. In-vitro results were revalidated in EAC solid tumor and CAM xenograft model.

KEY FINDINGS

Solanidine exerts its potential effect in a target specific manner. The cytotoxic/anticlonogenic activity was due to induction of typical cellular apoptotic hallmarks and cell cycle blockage at S-G2/M phase. The molecular events underlying this effect is through activation of intrinsic pathway via Bax, Bad and Cytochrome c activation by neutralizing Bcl-2 expression, along with downregulated PI3K/Akt survival signal. As a consequence, downstream pro apoptogenic gene, active Caspase-3 was over expressed by Solanidine to cleave its substrate PARP and promotes nuclear import of DFF-40. Anti-carcinogenic aptitude was further confirmed by murine solid tumors and in-vivo CAM xenograft studies.

SIGNIFICANCE

Solanidine emerged as active molecule against tomorigenesis by activating nuclear import of DFF-40 mediated nucleosomal disruption and cell demise. It can be developed as a potential apoptogenic small molecule for cancer therapy.

Development of novel synthesized phthalazinone-based PARP-1 inhibitors with apoptosis inducing mechanism in lung cancer

Herein we report the synthesis of two series of 4-phenylphthalazin-1-ones 11a-i and 4- benzylphthalazin-1-ones 16a-h as anti-lung adenocarcinoma agents with potential inhibitory activity against PARP-1. All the newly synthesized phthalazinones were evaluated for their anti-proliferative activity against A549 lung carcinoma cell line. Phthalazinones 11c-i and 16b, c showed significant cytotoxic activity against A549 cells at different concentrations (0.1, 1 and 10 μM) for two time intervals (24 h and 48 h). These nine phthalazinones were further examined for their inhibitory activity towards PARP-1. Compound 11c emerged as the most potent PARP-1 inhibitor with IC₅₀ value of 97 nM, compared to that of Olaparib (IC₅₀ = 139 nM). Furthermore, all these nine phthalazinones passed the filters of Lipinski and Veber rules, and predicted to have good pharmacokinetics properties in a theoretical kinetic study. On the other hand, western blotting in A549 cells revealed the enhanced expression of the cleaved PARP-1, alongside, with the reduced expression of pro-caspase-3 and phosphorylated AKT. In addition, ELISA assay confirmed the up-regulation of active caspase-3 and caspase-9 levels compared to the control, suggesting the activation of the apoptotic machinery in the A549 cells. Finally, molecular docking of 11c into PARP-1 active site (PDB: 5WRZ) was performed to explore the probable binding mode.

Methanolic extract of Euchelus asper exhibits in-ovo anti-angiogenic and in vitro anti-proliferative activities

Background

The marine environment is a rich source of bioactive natural products. Many of the marine bioactive compounds have been derived successfully from molluscs. Euchelus asper is a marine mollusc which is commonly found in the intertidal rocky regions of the Mumbai coast. The present study was focused on evaluating the anti-angiogenic and anti- proliferative activities of methanolic extract of Euchelus asper (EAME).

Methods

The anti-angiogenic activity of EAME (50–800 μg/mL) was assessed by chick chorio-allantoic membrane (CAM) model wherein multiple parameters in the CAM blood vessels were analysed through morphometric and histological investigations. In vitro testing of EAME (5–20 μg/mL) included its cytotoxicity against three different cancer cell lines, its effect on cell proliferation by wound healing assay as well as their relevant molecular mechanisms. Statistical analysis was carried out by two-tailed student’s t test for two unpaired groups.

Results

Analysis of CAM revealed that the extract is effective in reducing the branching points of the 1st order blood vessels or capillaries of CAM. Histological analysis of CAM showed significant decrease in capillary plexus and compartmentalization along with increase in mesodermal blood vessels, thus establishing its anti-angiogenicity. Further, EAME exhibited moderate but significant cytotoxicity against A549 non-small cell lung carcinoma cell line. We also demonstrated that the cytotoxicity of EAME in A549 was associated with its apoptotic activity by subG1 phase arrest. Lastly, EAME significantly reduced A549 proliferation by reducing the expression of Matrix metalloproteinase-2 (MMP-2) and Matrix metalloproteinase-9 (MMP-9).

Conclusion

Overall, our study suggested that EAME has potential to inhibit tumour angiogenic and proliferative activity and may be a potential source for development of new anti-cancer pharmaceuticals.

Ginsenoside Re Protects Trimethyltin-Induced Neurotoxicity via Activation of IL-6-Mediated Phosphoinositol 3-Kinase/Akt Signaling in Mice

Ginseng (Panax ginseng), an herbal medicine, has been used to prevent neurodegenerative disorders. Ginsenosides (e.g., Re, Rb1, or Rg1) were obtained from Korean mountain cultivated ginseng. The anticonvulsant activity of ginsenoside Re (20 mg/kg/day × 3) against trimethyltin (TMT) insult was the most pronounced out of ginsenosides (e.g., Re, Rb1, and Rg1). Re itself did not significantly alter tumor necrosis factor-α (TNF-α), interferon-ϒ (IFN-ϒ), and interleukin-1β (IL-1β) expression, however, it significantly increases the interleukin-6 (IL-6) expression. In addition, Re attenuated the TMT-induced decreases in IL-6 protein level. Therefore, IL-6 knockout (-/-) mice were employed to investigate whether Re requires IL-6-dependent neuroprotective activity against TMT toxicity. Re significantly attenuated TMT-induced lipid peroxidation, protein peroxidation, and reactive oxygen species in the hippocampus. Re-mediated antioxidant effects were more pronounced in IL-6 (-/-) mice than in WT mice. Consistently, TMT-induced increase in c-Fos-immunoreactivity (c-Fos-IR), TUNEL-positive cells, and nuclear chromatin clumping in the dentate gyrus of the hippocampus were significantly attenuated by Re. Furthermore, Re attenuated TMT-induced proapoptotic changes. Protective potentials by Re were comparable to those by recombinant IL-6 protein (rIL-6) against TMT-insult in IL-6 (-/-) mice. Moreover, treatment with a phosphoinositol 3-kinase (PI3K) inhibitor, LY294002 (1.6 µg, i.c.v) counteracted the protective potential mediated by Re or rIL-6 against TMT insult. The results suggest that ginsenoside Re requires IL-6-dependent PI3K/Akt signaling for its protective potential against TMT-induced neurotoxicity.

Development of 1,3,4-oxadiazole thione based novel anticancer agents: Design, synthesis and in-vitro studies

A series of new 1,3,4-oxadiazole-2(3H)-thione analogues (3a to 3o) have been designed, synthesized and evaluated for their anticancer activity. Four different cancerous cell lines viz. HeLa (cervical), U-87 (glioblastoma), Panc (pancreatic) and MCF-7 (breast) were used to assess the potency of the synthesized compounds as anticancer agents. Among them 3i and 3j showed promising cytotoxicity against HeLa cell line. Further, 3i and 3j successfully inhibited cell cycle progression and displayed cell death in HeLa cells via apoptosis as visualized by Annexin V APC and DNA fragmentation assay. 3i and 3j induced caspase-3 activation, PARP cleavage, increase in expression of proapoptotic protein Bax and decrease in the expression of antiapoptotic protein Bcl-2. Also, 3i and 3j induced overexpression of p21 and decreased expression of cyclin B1 indicating the arrest of cells in G₂-M phase of the cell cycle. Therefore, new lead compounds are being suggested having anticancer activity through cell cycle inhibition and apoptosis.

A comparative assessment of antiproliferative properties of resveratrol and ethanol leaf extract of Anogeissus leiocarpus (DC) Guill and Perr against HepG2 hepatocarcinoma cells

Background

Epidemiological and experimental evidences have shown cancer as a leading cause of death worldwide. Although the folklore use of plants as a reliable source of health-restoring principles is well-documented, the search for more of such plants that are active against diseases, such as cancer, continues. We report here a laboratory-based evidence of the relevance of an ethanol leaf extract of Anogeissus leiocarpus (A2L) in comparison with resveratrol, a natural polyphenol, in cancer therapy.

Methods

The quantitative assessment of flavonoid and phenolic contents involved quercetin and gallic acid as standards, respectively were determined using spectrophotometry. Cytotoxicity was determined fluorometrically using propidium-iodide-staining method. Antioxidant status, adenosine triphosphate (ATP) levels, caspase activities and mitochondrial integrity were assessed using fluorometry/luminometry.

Results

The antioxidant assay demonstrated that A2L possesses a strong antioxidant capacity as compared with the reference compounds, ascorbic acid and butylated hydroxytoluene. This is further buttressed by the significantly high level of phenolics obtained in the quantitative assessment of the extract. A 72-h post-treatment examination indicated that both A2L and resveratrol modulate the proliferation of HepG2 liver carcinoma cells in a time- and concentration-dependent manner. Determination of the total nuclei area, propidium-iodide negative and positive nuclei areas all further buttress the modulation of cell proliferation by A2L and resveratrol with the indication that the observed cell death is due to apoptosis and necrosis at lower and higher concentrations of treatments respectively. At lower concentrations (0.39–3.13 μg/mL), resveratrol possesses higher tendencies to activate caspases 3 and 7. Bioenergetically, both resveratrol and A2L do not adversely affect the cells at lower concentrations (0.39–6.25 μg/mL for resveratrol and 12.5–100.0 μg/mL for A2L) except at higher concentrations (12.5–25.0 μg/mL for resveratrol and 200–800 μg/mL for A2L) which are more pronounced in A2L-treated cells. Furthermore, the antioxidant status of HepG2 cells is not perturbed by resveratrol as compared with A2L. Assessment of 24-h post-treatment mitochondrial function shows that resveratrol is not mitotoxic as compared with A2L which exhibits mitotoxicity at its highest concentration.

Conclusions

Taken together, findings from this study showed that A2L possesses strong antiproliferative activity and its prospect in the management of hepatocellular carcinoma deserves further investigation.

The novel protein C9orf116 promotes rat liver cell line BRL-3A proliferation

Our previous study has proved that the chromosome 9 open reading frame 116 (C9orf116) (NM_001106564.1) was significantly up-regulated in the proliferation phase of liver regeneration. To study its possible physiological function, we analyzed the effect of C9orf116 on BRL-3A cells via over-expression and interference technique. MTT results showed that the cell viability of the interference group was significantly lower than the control group at 48h after transfection (P<0.05), whereas it was significantly higher in the over-expression group (P<0.05). The flow cytometry results showed that C9orf116 knockdown or over-expression had little effect on BRL-3A cell apoptosis. However, the number of cells in division phase (G2/M) was significantly reduced in the interference group (P<0.05), but significantly increased in the over-expression group (P<0.01). Furthermore, the expressions of cell proliferation-related genes CCNA2, CCND1 and MYC both at mRNA and protein levels were down-regulated in the interference group and up-regulated in the over-expression group. Therefore, we concluded that C9orf116 may promote cell proliferation by modulating cell cycle transition and the expression of key genes CCNA2, CCND1 and MYC in BRL-3A cells.

Biological evaluation of octahydropyrazin[2,1-a:5,4-a']diisoquinoline derivatives as potent anticancer agents

In this study, we evaluated the cytotoxic activity and antiproliferative potency of novel octahydropyrazin[2,1-a:5,4-a']diisoquinoline derivatives (1-7) in MCF-7 and MDA-MB-231 breast cancer cell lines. Annexin V binding assay and disruption of the mitochondrial potential were performed to determine apoptosis. The activity of caspases 3, 8, 9, and 10 was measured after 24 h of incubation with tested compounds to explain detailed molecular mechanism of induction of apoptosis. The results from experiments were compared with effects obtained after incubation in the presence of camptothecin and etoposide. Our study demonstrated that the most active compounds in both analyzed breast cancer cell lines were compounds 3 and 4. We also observed that all compounds induced apoptosis. We demonstrated the higher activity of caspases 3, 8, 9, and 10, which confirmed that induction of apoptosis is associated with external and internal cell death pathway. Our study revealed that the novel compounds in group of diisoquinoline derivatives are promising candidates in anticancer treatment by activation of both extrinsic and intrinsic apoptotic pathways.

Plant Sterol Esters in Extruded Food Model Inhibits Colon Carcinogenesis by Suppressing Inflammation and Stimulating Apoptosis

Plant sterols in their free forms are known to inhibit colon cancer. Whether these activities persist when compounds are incorporated into processed food is not reported yet. This study aimed to test the ability of plant sterol esters (PSE) incorporated into a nonpuffed extruded food (NPE) model to inhibit colon carcinogenesis. PSE was added into NPE at four concentrations (0.0%, 0.7%, 1.4%, and 2.1%). PSE-NPE activity was tested in azoxymethane/dextran sodium sulfate-induced Balb/c mice. The groups given PSE-NPE did not show any colon tumor formation. Immunohistochemistry results revealed that the group fed with 1.4% PSE had the lowest histoscore for cyclooxygenase-2 expression and the highest histoscore for cleaved caspase-3, cleaved caspase-8, and cleaved caspase-9expressions. The results of this study indicated that even after incorporation into a food system, which is processed using high pressure and temperature, PSE retained its chemopreventive activity. The proposed mechanisms are by suppressing inflammation and inducing apoptosis.

Marine Mollusk-Derived Agents with Antiproliferative Activity as Promising Anticancer Agents to Overcome Chemotherapy Resistance

The chemical investigation of marine mollusks has led to the isolation of a wide variety of bioactive metabolites, which evolved in marine organisms as favorable adaptations to survive in different environments. Most of them are derived from food sources, but they can be also biosynthesized de novo by the mollusks themselves, or produced by symbionts. Consequently, the isolated compounds cannot be strictly considered as "chemotaxonomic markers" for the different molluscan species. However, the chemical investigation of this phylum has provided many compounds of interest as potential anticancer drugs that assume particular importance in the light of the growing literature on cancer biology and chemotherapy. The current review highlights the diversity of chemical structures, mechanisms of action, and, most importantly, the potential of mollusk-derived metabolites as anticancer agents, including those biosynthesized by mollusks and those of dietary origin. After the discussion of dolastatins and kahalalides, compounds previously studied in clinical trials, the review covers potentially promising anticancer agents, which are grouped based on their structural type and include terpenes, steroids, peptides, polyketides and nitrogen-containing compounds. The "promise" of a mollusk-derived natural product as an anticancer agent is evaluated on the basis of its ability to target biological characteristics of cancer cells responsible for poor treatment outcomes. These characteristics include high antiproliferative potency against cancer cells in vitro, preferential inhibition of the proliferation of cancer cells over normal ones, mechanism of action via nonapoptotic signaling pathways, circumvention of multidrug resistance phenotype, and high activity in vivo, among others. The review also includes sections on the targeted delivery of mollusk-derived anticancer agents and solutions to their procurement in quantity.

Modulatory efficacy of dieckol on xenobiotic-metabolizing enzymes, cell proliferation, apoptosis, invasion and angiogenesis during NDEA-induced rat hepatocarcinogenesis

Dieckol (DEK) is a major polyphenol of marine brown seaweed Ecklonia cava which is a potential candidate for cancer therapy. However, the underlying mechanism of DEK as an anticancer drug remains to be elucidated. In this study, we evaluated the molecular mechanisms involved in the chemopreventive efficacy of DEK in N-nitrosodiethylamine (NDEA)-induced hepatocarcinogenesis rats by analyzing markers of xenobiotic-metabolizing enzymes (XMEs), apoptosis, invasion, and angiogenesis. Rats administered NDEA developed hepatocarcinogenesis that displayed apoptosis avoidance coupled to upregulation of pro-inflammatory, invasion, and angiogenesis markers. Treatment of DEK effectively suppressed the NDEA-initiated hepatocarcinogenesis by modulation of XMEs, inducing of apoptosis via the mitochondrial pathway as revealed by modulating the Bcl-2 family proteins, cytochrome C, caspases, and inhibiting invasion, and angiogenesis as evidenced by changes in the activities of MMPs (MMP2/9) and the expression of VEGF. In addition, DEK exerts its anticancer effects via inhibition of pro-inflammatory transcription factor NF-κB (nuclear factor κB) and COX2 in NDEA-induced hepatocarcinogenesis. Taken together, this study demonstrates that DEK modulates the expression of key molecules that regulate apoptosis, inflammation, invasion, and angiogenesis. These results strongly indicate that DEK from E. cava is an attractive candidate for chemoprevention.

Comprehensive CircRNA expression profile and selection of key CircRNAs during priming phase of rat liver regeneration

BACKGROUND

Rat liver regeneration (LR) proceeds along a process of highly organized and ordered tissue growth in response to the loss or injury of liver tissue, during which many physiological processes may play important roles. The molecular mechanism of hepatocyte proliferation, energy metabolism and substance metabolism during rat LR had been elucidated. Further, the correlation of circular RNA (circRNA) abundance with proliferation has recently been clarified. However, the regulatory capacity of circRNA in rat LR remains a fascinating topic.

RESULTS

To investigate the regulatory mechanism of circRNA during priming phase of rat LR, high-throughput RNA sequencing technology was performed to unbiasedly profile the expression of circRNA during priming phase of rat LR. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) biological pathway analysis was conducted to predict the functions of differentially expressed circRNAs and their host linear transcripts. Co-expression networks of circRNA-miRNA were constructed based on the correlation analysis between the differentially expressed LR-related circRNAs and the condition of their miRNA binding sites. To excavate the key circRNAs in the early phase of rat LR, we comprehensively evaluated and integrated the relationship of expression level between the circRNAs and the linear transcripts as well as the distribution of miRNA binding sites in circRNA sequences.

CONCLUSIONS

This paper is the first to employ the comprehensive circRNA expression profile and to investigate circRNA-miRNA interactions during priming phase of rat LR. Two thousand four hundred twelve circRNAs were detected, and 159 circRNAs deriving from 116 host linear transcripts differentially expressed (p < 0.05). Six significantly changed circRNAs during priming phase of rat LR were screened as key circle molecules, and then were validated by qRT-PCR. This study will lay the foundation for revealing the functional roles of circRNAs during rat LR and help solve the remaining clinical problems.

Inhibition of IKK-NFκB pathway sensitizes lung cancer cell lines to radiation

Objective

: Cancer cell radioresistance is a stumbling block in radiation therapy. The activity in the nuclear factor kappa B (NFκB) pathway correlates with anti-apoptotic mechanisms and increased radioresistance. The IKK complex plays a major role in NFκB activation upon numerous signals. In this study, we examined the interaction between ionizing radiation (IR) and different members of the IKK-NFκB pathway, as well as upstream activators, RAF1, ERK, and AKT1.

Methods

: The effect of 4 Gy of IR on the expression of the RAF1-ERK-IKK-NFκB pathway was examined in A549 and H1299 lung cancer cell lines using Western blot analysis and confocal microscopy. We examined changes in radiation sensitivity using gene silencing or pharmacological inhibitors of ERK and IKKβ.

Results

: IKKα, IKKγ, and IκBα increased upon exposure to IR, thereby affecting nuclear levels of NFκB (phospho-p65). ERK inhibition or siRNA-mediated down-regulation of RAF1 suppressed the post-irradiation survival of the examined lung cancer cell lines. A similar effect was detected on survival upon silencing IKKα/IKKγ or inhibiting IKKβ.

Conclusions

: Exposure of lung cancer cells to IR results in NFκB activation via IKK. The genetic or pharmacological blockage of the RAF1-ERK-IKK-NFκB pathway sensitizes cells to therapeutic doses of radiation. Therefore, the IKK pathway is a promising target for therapeutic intervention in combination with radiotherapy.

EMODIN EFFICACY ON THE AKT, MAPK, ERK AND DNMT EXPRESSION PATTERN DURING DMBA-INDUCED ORAL CARCINOMA IN GOLDEN SYRIAN HAMSTERS

Background:

The present study has evaluated the Emodin efficacy on the Akt, MAPK, ERK and DNMT expression pattern during 7,12-dimethylbenz[a]anthracene (DMBA)-induced oral carcinoma in golden Syrian hamsters, in order to explore its antitumor potential.

Materials and methods:

Oral tumors were developed in the buccal pouches of golden Syrian hamsters using the carcinogen, DMBA.

Results:

While the incidence of tumor formation was 100% in hamsters treated with DMBA alone, the tumor formation was not noticed in DMBA+ Emodin treated hamsters. Also, Emodin reduced the severity of precancerous pathological lesions such as dysplasia, in the hamsters treated with DMBA. Emodin administration corrected the abnormalities in the expression pattern of Akt, MAPK, ERK and DNMT in the buccal mucosa of hamsters treated with DMBA.

Conclusions:

The present study thus suggests that the tumor preventive potential of Emodin is partly related to its modulating effect on the Akt, MAPK, ERK and DNMT expression pattern, as these molecular markers have a pivotal role in the process of cell proliferation, inflammation, invasion, and apoptosis.

Cardioprotective Effect of Electroacupuncture Pretreatment on Myocardial Ischemia/Reperfusion Injury via Antiapoptotic Signaling

Objectives. Our previous study has used RNA-seq technology to show that apoptotic molecules were involved in the myocardial protection of electroacupuncture pretreatment (EAP) on the ischemia/reperfusion (I/R) animal model. Therefore, this study was designed to investigate how EAP protects myocardium against myocardial I/R injury through antiapoptotic mechanism. Methods. By using rats with myocardial I/R, we ligated the left anterior descending artery (LAD) for 30 minutes followed by 4 hr of reperfusion after EAP at the Neiguan (PC6) acupoint for 12 days; we employed arrhythmia scores, serum myocardial enzymes, and cardiac troponin T (cTnT) to evaluate the cardioprotective effect. Heart tissues were harvested for western blot analyses for the expressions of pro- and antiapoptotic signaling molecules. Results. Our preliminary findings showed that EAP increased the survival of the animals along with declined arrhythmia scores and decreased CK, LDH, CK-Mb, and cTnT levels. Further analyses with the heart tissues detected reduced myocardial fiber damage, decreased number of apoptotic cells and the protein expressions of Cyt c and cleaved caspase 3, and the elevated level of Endo G and AIF after EAP intervention. At the same time, the protein expressions of antiapoptotic molecules, including Xiap, BclxL, and Bcl2, were obviously increased. Conclusions. The present study suggested that EAP protected the myocardium from I/R injury at least partially through the activation of endogenous antiapoptotic signaling.

Molecular mechanisms of cell death in intervertebral disc degeneration (Review)

Intervertebral discs (IVDs) are complex structures that consist of three parts, namely, nucleus pulposus, annulus fibrosus and cartilage endplates. With aging, IVDs gradually degenerate as a consequence of many factors, such as microenvironment changes and cell death. Human clinical trial and animal model studies have documented that cell death, particularly apoptosis and autophagy, significantly contribute to IVD degeneration. The mechanisms underlying this phenomenon include the activation of apoptotic pathways and the regulation of autophagy in response to nutrient deprivation and multiple stresses. In this review, we briefly summarize recent progress in understanding the function and regulation of apoptosis and autophagy signaling pathways. In particular, we focus on studies that reveal the functional mechanisms of these pathways in IVD degeneration.

Assessment of Radiation Induced Therapeutic Effect and Cytotoxicity in Cancer Patients Based on Transcriptomic Profiling

Toxicity induced by radiation therapy is a curse for cancer patients undergoing treatment. It is imperative to understand and define an ideal condition where the positive effects notably outweigh the negative. We used a microarray meta-analysis approach to measure global gene-expression before and after radiation exposure. Bioinformatic tools were used for pathways, network, gene ontology and toxicity related studies. We found 429 differentially expressed genes at fold change >2 and p-value <0.05. The most significantly upregulated genes were synuclein alpha (SNCA), carbonic anhydrase I (CA1), X-linked Kx blood group (XK), glycophorin A and B (GYPA and GYPB), and hemogen (HEMGN), while downregulated ones were membrane-spanning 4-domains, subfamily A member 1 (MS4A1), immunoglobulin heavy constant mu (IGHM), chemokine (C-C motif) receptor 7 (CCR7), BTB and CNC homology 1 transcription factor 2 (BACH2), and B-cell CLL/lymphoma 11B (BCL11B). Pathway analysis revealed calcium-induced T lymphocyte apoptosis and the role of nuclear factor of activated T-cells (NFAT) in regulation of the immune response as the most inhibited pathways, while apoptosis signaling was significantly activated. Most of the normal biofunctions were significantly decreased while cell death and survival process were activated. Gene ontology enrichment analysis revealed the immune system process as the most overrepresented group under the biological process category. Toxicity function analysis identified liver, kidney and heart to be the most affected organs during and after radiation therapy. The identified biomarkers and alterations in molecular pathways induced by radiation therapy should be further investigated to reduce the cytotoxicity and development of fatigue.

Insight to drug delivery aspects for colorectal cancer

Colorectal cancer (CRC) is the third most common cancer diagnosed worldwide in human beings. Surgery, chemotherapy, radiotherapy and targeted therapies are the conventional four approaches which are currently used for the treatment of CRC. The site specific delivery of chemotherapeutics to their site of action would increase effectiveness with reducing side effects. Targeted oral drug delivery systems based on polysaccharides are being investigated to target and deliver chemotherapeutic and chemopreventive agents directly to colon and rectum. Site-specific drug delivery to colon increases its concentration at the target site, and thus requires a lower dose and hence abridged side effects. Some novel therapies are also briefly discussed in article such as receptor (epidermal growth factor receptor, folate receptor, wheat germ agglutinin, VEGF receptor, hyaluronic acid receptor) based targeting therapy; colon targeted proapoptotic anticancer drug delivery system, gene therapy. Even though good treatment options are available for CRC, the ultimate therapeutic approach is to avert the incidence of CRC. It was also found that CRCs could be prevented by diet and nutrition such as calcium, vitamin D, curcumin, quercetin and fish oil supplements. Immunotherapy and vaccination are used nowadays which are showing better results against CRC.

Apoptosis Markers in Breast Cancer Therapy

Cancer is a disease characterized by a very little apoptosis, ie, genetically programmed cell death. Aberrations in apoptotic pathways are central to tumorigenesis, tumor progression, and overall tumor growth and regression in response to chemotherapy. It is now increasingly accepted that chemotherapeutic drug efficacy is partially related to its ability to induce apoptosis. Apoptosis, therefore, represents not only a vital target in cancer therapy but also a unique biomarker opportunity that has thus far been largely unexploited. In response to therapy, tumor cells undergo apoptosis and release their cellular components in the circulation. As such, these materials may serve as biomarkers to assess response. Apoptosis markers in breast cancer include circulating soluble FasL, granzyme B, and cytochrome c that increase following chemotherapy. Unfortunately, there is a paucity of information in the literature with respect to this approach. As such, large-scale prospective studies are clearly needed to validate this approach and more fully elucidate clinical usefulness.

Sulforaphane Induces Cell Death Through G2/M Phase Arrest and Triggers Apoptosis in HCT 116 Human Colon Cancer Cells

Sulforaphane (SFN), an isothiocyanate, exists exclusively in cruciferous vegetables, and has been shown to possess potent antitumor and chemopreventive activity. However, there is no available information that shows SFN affecting human colon cancer HCT 116 cells. In the present study, we found that SFN induced cell morphological changes, which were photographed by contrast-phase microscopy, and decreased viability. SFN also induced G2/M phase arrest and cell apoptosis in HCT 116 cells, which were measured with flow cytometric assays. Western blotting indicated that SFN increased Cyclin A, cdk 2, Cyclin B and WEE1, but decreased Cdc 25C, cdk1 protein expressions that led to G2/M phase arrest. Apoptotic cell death was also confirmed by Annexin V/PI and DAPI staining and DNA gel electrophoresis in HCT 116 cells after exposure to SFN. The flow cytometric assay also showed that SFN induced the generation of reactive oxygen species (ROS) and Ca[Formula: see text] and decreased mitochondria membrane potential and increased caspase-8, -9 and -3 activities in HCT 116 cell. Western blotting also showed that SFN induced the release of cytochrome c, and AIF, which was confirmed by confocal microscopy examination. SFN induced ER stress-associated protein expression. Based on those observations, we suggest that SFN may be used as a novel anticancer agent for the treatment of human colon cancer in the future.

Killing cancer with platycodin D through multiple mechanisms

Cancer is a multi-faceted disease comprised of a combination of genetic, epigenetic, metabolic and signalling aberrations which severely disrupt the normal homoeostasis of cell growth and death. Rational developments of highly selective drugs which specifically block only one of the signalling pathways have been associated with limited therapeutic success. Multi-targeted prevention of cancer has emerged as a new paradigm for effective anti-cancer treatment. Platycodin D, a triterpenoid saponin, is one the major active components of the roots of Platycodon grandiflorum and possesses multiple biological and pharmacological properties including, anti-nociceptive, anti-atherosclerosis, antiviral, anti-inflammatory, anti-obesity, immunoregulatory, hepatoprotective and anti-tumour activities. Recently, the anti-cancer activity of platycodin D has been extensively studied. The purpose of this review was to give our perspectives on the current status of platycodin D and discuss its anti-cancer activity and molecular mechanisms which may help the further design and conduct of pre-clinical and clinical trials to develop it successfully into a potential lead drug for oncological therapy. Platycodin D has been shown to fight cancer by inducing apoptosis, cell cycle arrest, and autophagy and inhibiting angiogenesis, invasion and metastasis by targeting multiple signalling pathways which are frequently deregulated in cancers suggesting that this multi-target activity rather than a single effect may play an important role in developing platycodin D into potential anti-cancer drug.

Structure-Activity Relationship of Synthetic 2-Phenylnaphthalenes with Hydroxyl Groups that Inhibit Proliferation and Induce Apoptosis of MCF-7 Cancer Cells

In this study, six 2-phenylnaphthalenes with hydroxyl groups were synthesized in high yields by the demethylation of the corresponding methoxy-2-phenylnaphthalenes, and one 2-phenylnaphthalene with an amino group was obtained by hydrogenation. All of the 2-phenylnaphthalene derivatives were evaluated for cytotoxicity, and the structure-activity relationship (SAR) against human breast cancer (MCF-7) cells was also determined. The SAR results revealed that cytotoxicity was markedly promoted by the hydroxyl group at the C-7 position of the naphthalene ring. The introduction of hydroxyl groups at the C-6 position of the naphthalene ring and the C-4' position of the phenyl ring fairly enhanced cytotoxicity, but the introduction of a hydroxyl group at the C-3' position of the phenyl ring slightly decreased cytotoxicity. Overall, 6,7-dihydroxy-2-(4'-hydroxyphenyl)naphthalene (PNAP-6h) exhibited the best cytotoxicity, with an IC50 value of 4.8 μM against the MCF-7 cell line, and showed low toxicity toward normal human mammary epithelial cells (MCF-10A). PNAP-6h led to cell arrest at the S phase, most likely due to increasing levels of p21 and p27 and decreasing levels of cyclin D1, CDK4, cyclin E, and CDK2. In addition, PNAP-6h decreased CDK1 and cyclin B1 expression, most likely leading to G2/M arrest, and induced morphological changes, such as nuclear shrinkage, nuclear fragmentation, and nuclear hypercondensation, as observed by Hoechst 33342 staining. PNAP-6h induced apoptosis, most likely by the promotion of Fas expression, increased PARP activity, caspase-7, caspase-8, and caspase-9 expression, the Bax/Bcl-2 ratio, and the phosphorylation of p38, and decreased the phosphorylation of ERK. This study provides the first demonstration of the cytotoxicity of PNAPs against MCF-7 cells and elucidates the mechanism underlying PNAP-induced cytotoxicity.

Selenocystine-induced cell apoptosis and S-phase arrest inhibit human triple-negative breast cancer cell proliferation

Triple-negative breast cancer (TNBC) is an aggressive subtype of breast cancer with limited effective treatment options. New therapeutic approaches are urgently needed to improve the prognosis of TNBC. Here we demonstrated that a redox modulator, selenocystine (SeC), significantly inhibits TNBC cell proliferation in a dose- and time-dependent manner. Through cell apoptosis assays and cell cycle distribution analyses, we have shown that the in vitro inhibitory effect of SeC on TNBC cells can be attributed to the induction of apoptosis and the S-phase arrest in a dose-dependent manner. Therefore, this finding implies that SeC potentially is a novel therapeutic agent for TNBC.

Can Some Marine-Derived Fungal Metabolites Become Actual Anticancer Agents?

Marine fungi are known to produce structurally unique secondary metabolites, and more than 1000 marine fungal-derived metabolites have already been reported. Despite the absence of marine fungal-derived metabolites in the current clinical pipeline, dozens of them have been classified as potential chemotherapy candidates because of their anticancer activity. Over the last decade, several comprehensive reviews have covered the potential anticancer activity of marine fungal-derived metabolites. However, these reviews consider the term "cytotoxicity" to be synonymous with "anticancer agent", which is not actually true. Indeed, a cytotoxic compound is by definition a poisonous compound. To become a potential anticancer agent, a cytotoxic compound must at least display (i) selectivity between normal and cancer cells (ii) activity against multidrug-resistant (MDR) cancer cells; and (iii) a preferentially non-apoptotic cell death mechanism, as it is now well known that a high proportion of cancer cells that resist chemotherapy are in fact apoptosis-resistant cancer cells against which pro-apoptotic drugs have more than limited efficacy. The present review thus focuses on the cytotoxic marine fungal-derived metabolites whose ability to kill cancer cells has been reported in the literature. Particular attention is paid to the compounds that kill cancer cells through non-apoptotic cell death mechanisms.

Autophagy and senescence in fibrosing cholangiopathies

Fibrosing cholangiopathy such as primary sclerosing cholangitis (PSC) and biliary atresia (BA) is characterized by biliary epithelial injuries and concentric fibrous obliteration of the biliary tree together with inflammatory cell infiltration. In these diseases, inappropriate innate immunity is reported to contribute more to bile duct pathology as compared with various aspects of "classical" autoimmune diseases. Primary biliary cirrhosis (PBC) is characterized by chronic cholangitis with bile duct loss and classical autoimmune features. Cellular senescence of cholangiocytes and a senescence-associated secretory phenotype lead to the production of proinflammatory cytokines and chemokines that may modify the milieu of the bile duct and then trigger fibroinflammatory responses in PSC and PBC. Furthermore, deregulated autophagy might be involved in cholangiocyte senescence and possibly in the autoimmune process in PBC, and the deregulated innate immunity against enteric microbes or their products that is associated with cholangiocyte senescence might result in the fibrosing cholangitis that develops in PBC and PSC. In BA, innate immunity against double-stranded RNA viruses might be involved in cholangiocyte apoptosis and also in the development of the epithelial-mesenchymal transition of cholangiocytes that results in fibrous obliteration of bile ducts. These recent advances in the understanding of immune-mediated biliary diseases represent a paradigm shift: the cholangiocyte is no longer viewed merely as a passive victim of injury; it is now also considered to function as a potential effector in bile duct pathology.

Potential roles of Centipede Scolopendra extracts as a strategy against EGFR-dependent cancers

Centipede Scolopendra, a commonly used traditional Chinese medicine, has been shown to have anti-cancer effects. In this study, the inhibitory effect of alcohol extracts of Centipede Scolopendra (AECS) was more prominent when treating cells highly expressing epidermal growth factor receptor (EGFR) (A431 and HEK293/EGFR cells versus HEK293 cells). The elution profiles of AECS on cell membrane chromatography (CMC) column showed that AECS could bind to EGFR, and competition studies indicated that AECS and gefitinib may have direct competition at a single common binding site on EGFR. SiRNA knockdown of EGFR in A431 cells attenuated AECS effects, suggesting that EGFR was a target mediated by AECS. In a cell culture system, AECS dramatically induced apoptosis of A431 and HEK293/EGFR cells, which was associated with the effects on Bcl-2 family. Furthermore, AECS could alter EGFR kinase activity and reduce phosphorylation of EGFR and downstream signaling players AKT and Erk1/2. The mechanism of AECS to inhibit high-EGFR expression cell proliferation is due to its ability to induce apoptosis and modulate the EGFR pathway. This study might provide a novel therapy for cancer with high-EGFR expression.

Caspase-14 expression impairs retinal pigment epithelium barrier function: potential role in diabetic macular edema

We recently showed that caspase-14 is a novel molecule in retina with potential role in accelerated vascular cell death during diabetic retinopathy (DR). Here, we evaluated whether caspase-14 is implicated in retinal pigment epithelial cells (RPE) dysfunction under hyperglycemia. The impact of high glucose (HG, 30 mM D-glucose) on caspase-14 expression in human RPE (ARPE-19) cells was tested, which showed significant increase in caspase-14 expression compared with normal glucose (5 mM D-glucose + 25 mM L-glucose). We also evaluated the impact of modulating caspase-14 expression on RPE cells barrier function, phagocytosis, and activation of other caspases using ARPE-19 cells transfected with caspase-14 plasmid or caspase-14 siRNA. We used FITC-dextran flux assay and electric cell substrate impedance sensing (ECIS) to test the changes in RPE cell barrier function. Similar to HG, caspase-14 expression in ARPE-19 cells increased FITC-dextran leakage through the confluent monolayer and decreased the transcellular electrical resistance (TER). These effects of HG were prevented by caspase-14 knockdown. Furthermore, caspase-14 knockdown prevented the HG-induced activation of caspase-1 and caspase-9, the only activated caspases by HG. Phagocytic activity was unaffected by caspase-14 expression. Our results suggest that caspase-14 contributes to RPE cell barrier disruption under hyperglycemic conditions and thus plays a role in the development of diabetic macular edema.

The effects of bioactive compounds from plant foods on mitochondrial function: a focus on apoptotic mechanisms

Mitochondria are essential organelles for cellular integrity and functionality maintenance and their imparement is implicated in the development of a wide range of diseases, including metabolic, cardiovascular, degenerative and hyperproliferative pathologies. The identification of different compounds able to interact with mitochondria for therapeutic purposes is currently becoming of primary importance. Indeed, it is well known that foods, particularly those of vegetable origin, present several constituents with beneficial effects on health. This review summarizes and updates the most recent findings concerning the mechanisms through which different dietary compounds from plant foods affect mitochondria functionality in healthy and pathological in vitro and in vivo models, paying particular attention to the pathways involved in mitochondrial biogenesis and apoptosis.

Cell death paradigms in the pathogenesis of Mycobacterium tuberculosis infection

Cell death or senescence is a fundamental event that helps maintain cellular homeostasis, shapes the growth of organism, and provides protective immunity against invading pathogens. Decreased or increased cell death is detrimental both in infectious and non-infectious diseases. Cell death is executed both by regulated enzymic reactions and non-enzymic sudden collapse. In this brief review we have tried to summarize various cell death modalities and their impact on the pathogenesis of Mycobacterium tuberculosis.

Marine invertebrate natural products for anti-inflammatory and chronic diseases

The marine environment represents a relatively available source of functional ingredients that can be applied to various aspects of food processing, storage, and fortification. Moreover, numerous marine invertebrates based compounds have biological activities and also interfere with the pathogenesis of diseases. Isolated compounds from marine invertebrates have been shown to pharmacological activities and are helpful for the invention and discovery of bioactive compounds, primarily for deadly diseases like cancer, acquired immunodeficiency syndrome (AIDS), osteoporosis, and so forth. Extensive research within the last decade has revealed that most chronic illnesses such as cancer, neurological diseases, diabetes, and autoimmune diseases exhibit dysregulation of multiple cell signaling pathways that have been linked to inflammation. On the basis of their bioactive properties, this review focuses on the potential use of marine invertebrate derived compounds on anti-inflammatory and some chronic diseases such as cardiovascular disease, osteoporosis, diabetes, HIV, and cancer.

Induction of apoptosis by total flavonoids from Scutellaria barbata D. Don in human hepatocarcinoma MHCC97-H cells via the mitochondrial pathway

Scutellaria barbata D. Don, a traditional Chinese medicine, reportedly possesses antitumor activity against a variety of tumors. In the present study, we investigated the cytotoxic effect of total flavonoids from S. barbata (TF-SB) on human hepatocarcinoma cells and the underlying molecular mechanisms regarding the effect were explored. TF-SB treatment significantly reduced the cell viability of human HCC MHCC97-H cells in a dose-dependent manner. Further flow cytometric analysis showed that the apoptosis rate of MHCC97-H cells increased and the mitochondrial membrane potential (∆ψm) of MHCC97-H cells decreased after TF-SB treatment. DNA ladder showed that TF-SB induced a significant increase in DNA fragmentation in MHCC97-H cells. Reverse transcription PCR and Western blot analysis revealed that the expression levels of Smac, Apaf-1, Cytochrome c, Caspase-9, and Caspase-3 were upregulated in a dose-dependent manner and after treatment with different concentrations of TF-SB for 48 h. These results suggest that TF-SB induces apoptosis in MHCC97-H cells through the mitochondrial pathway.

Editorial of the special issue: signaling molecules and signal transduction in cells

In the special issue “Signaling Molecules and Signal Transduction in Cells” authors were invited to submit papers regarding important and novel aspects of extra- and intracellular signaling which have implications on physiological and pathophysiological processes. These aspects included compounds which are involved in these processes, elucidation of signaling pathways, as well as novel techniques for the analysis of signaling pathways. In response, various novel and important topics are elucidated in this special issue.