Modulation of adenine phosphoribosyltransferase-mediated salvage pathway to accelerate diabetic wound healing.

Adenine phosphoribosyltransferase (APRT) is the key enzyme involved in purine salvage by the incorporation of adenine and phosphoribosyl pyrophosphate to provide adenylate nucleotides. To evaluate the role of APRT in the repair processes of cutaneous wounds in healthy skin and in diabetic patients, a diabetic mouse model (db/db) and age-matched wild-type mice were used. Moreover, the topical application of adenine was assessed. In vitro studies, analytical, histological, and immunohistochemical methods were used. Diabetic mice treated with adenine exhibited elevated ATP levels in organismic skin and accelerated wound healing. In vitro studies showed that APRT utilized adenine to rescue cellular ATP levels and proliferation from hydrogen peroxide-induced oxidative damage. HPLC-ESI-MS/MS-based analysis of total adenylate nucleotides in NIH-3T3 fibroblasts demonstrated that adenine addition enlarged the cellular adenylate pool, reduced the adenylate energy charge, and provided additional AMP for the further generation of ATP. These data indicate an upregulation of APRT in skin wounds, highlighting its role during the healing of diabetic wounds through regulation of the nucleotide pool after injury. Furthermore, topical adenine supplementation resulted in an enlargement of the adenylate pool needed for the generation of ATP, an important molecule for wound repair.

Adenine inhibits growth of hepatocellular carcinoma cells via AMPK-mediated S phase arrest and apoptotic cascade.

Background: Adenine exhibits potential anticancer activity against several types of malignancies. However, whether adenine has anticancer effects on hepatocellular carcinoma (HCC) cells is incompletely explored. Methods: Human HCC cell lines HepG2 and SK-Hep-1 (p53-wild type) and Hep3B (p53-deficient) were used as cell model. Cell growth and cell cycle distribution were determined using MTT assay and flow cytometric analysis, respectively. Protein expression and phosphorylation were assessed by Western blot. Involvement of AMP-activated protein kinase (AMPK) was evaluated using specific inhibitor and small inhibitory RNA (siRNA). Results: Adenine treatments (0.5 - 2 mM) clearly decreased the cell growth of Hep G2 and SK-Hep-1 cells to 72.5 ± 3.4% and 71.3 ± 4.6% of control, respectively. In parallel, adenine also induced sub-G1 and S phase accumulation in both HCC cells. However, adenine did not affect the cell growth and cell cycle distribution of Hep3B cell. Western blot analysis showed that adenine reduced expression of cyclin A/D1 and cyclin-dependent kinase (CDK)2 and upregulated p53, p21, Bax, PUMA, and NOXA in HepG2 cell. Moreover, adenine induced AMPK activation that was involved in the p53-associated apoptotic cascade in HepG2 cells. Inhibition of AMPK activation or knockdown of AMPK restored the decreased cell growth of HepG2 and SK-Hep-1 cells in response to adenine. Conclusions: These findings reveal that adenine reduces the cell growth of HepG2 and SK-Hep-1 but not Hep3B cells, attributing to the AMPK/p53-mediated S phase arrest and apoptosis. It suggests that adenine has anticancer potential against p53-wild type HCC cells and may be beneficial as an adjuvant for HCC treatment.

The anti-inflammatory function of adenine occurs through AMPK activation and its downstream transcriptional regulation in THP-1 cells.

Pathogenic bacteria induced sepsis is a risk factor for hospital mortality. Monocyte-derived inflammatory cytokines participate in the sepsis progression. The anti-inflammatory effect of adenine has been previously reported by our laboratory and others. However, the mechanism of action has different opinions and remains unclear in monocyte. Here, adenine was found to significantly inhibit the secretion of lipopolysaccharide-induced inflammatory cytokines such as TNF-α, IL-1ß and IL-6 in THP-1 cells. The bioinformatic analysis results showed that the anti-inflammatory function is possibly due to the inhibition of NF-κB signaling. And this result is confirmed by using immunocytochemistry. Moreover, this effect can be suppressed by the AMPK inhibitor. Results also showed that adenine can activate AMPK and its multiple downstream targets. Data from mass spectrometry showed that adenine promotes significant elevation of intracellular AMP. Our data indicate that the anti-inflammatory mechanism of adenine may involve adenine phosphoribosyltransferase-catalyzed intracellular AMP elevation, which stimulates AMPK activation.

Evaluation of disulfide scrambling during the enzymatic digestion of bevacizumab at various pH values using mass spectrometry.

Disulfide linkages play an important role in protein stability and activity. Thus, it is critical to characterize disulfide bonds to ensure the quality and function of protein pharmaceuticals. There are, however, problems associated with maintaining disulfide linkages in the conventional procedures that are used to digest a protein. In order to preserve enzyme activity during the digestion of a protein, it is commonly carried out at neutral to basic environment which increases the possibilities of disulfide bond scrambling. However, it is not easy to differentiate whether the scrambled disulfide linkages are initiated by the sample itself or whether they are induced during the protease digestion process. In this study, the optimum pH for minimizing disulfide bond rearrangements during the digestion process was determined. Three sets of proteases, trypsin plus Glu-C, Lys-C and thermolysin were used, followed by dimethyl labeling and mass spectrometry for a bevacizumab (Avastin) disulfide linkage analysis. No disulfide linkage scrambling was detected at pH6 when Lys-C or trypsin plus Glu-C were used as enzymes. When thermolysin was applied, some scrambled disulfide bonds were identified at pH5, 6 and 7. Nevertheless, there was less disulfide bond scrambling at a lower pH. All correct disulfide bonds on bevacizumab could be identified using this approach. The results demonstrated that by choosing the proper enzymes, using a lower pH environment for the digestion could reduce the degree of artifact disulfide scrambling.

The neuroprotective role of metformin in advanced glycation end product treated human neural stem cells is AMPK-dependent.

Diabetic neuronal damage results from hyperglycemia followed by increased formation of advanced glycosylation end products (AGEs), which leads to neurodegeneration, although the molecular mechanisms are still not well understood. Metformin, one of the most widely used anti-diabetic drugs, exerts its effects in part by activation of AMP-activated protein kinase (AMPK). AMPK is a critical evolutionarily conserved enzyme expressed in the liver, skeletal muscle and brain, and promotes cellular energy homeostasis and biogenesis by regulating several metabolic processes. While the mechanisms of AMPK as a metabolic regulator are well established, the neuronal role for AMPK is still unknown. In the present study, human neural stem cells (hNSCs) exposed to AGEs had significantly reduced cell viability, which correlated with decreased AMPK and mitochondria associated gene/protein (PGC1α, NRF-1 and Tfam) expressions, as well as increased activation of caspase 3 and 9 activities. Metformin prevented AGEs induced cytochrome c release from mitochondria into cytosol in the hNSCs. Co-treatment with metformin significantly abrogated the AGE-mediated effects in hNSCs. Metformin also significantly rescued hNSCs from AGE-mediated mitochondrial deficiency (lower ATP, D-loop level, mitochondrial mass, maximal respiratory function, COX activity, and mitochondrial membrane potential). Furthermore, co-treatment of hNSCs with metformin significantly blocked AGE-mediated reductions in the expression levels of several neuroprotective genes (PPARγ, Bcl-2 and CREB). These findings extend our understanding of the molecular mechanisms of both AGE-induced neuronal toxicity, and AMPK-dependent neuroprotection by metformin. This study further suggests that AMPK may be a potential therapeutic target for treating diabetic neurodegeneration.

Comparative proteome analysis reveals proteins involved in salt adaptation in Photobacterium damselae subsp. piscicida.

Proteomic approaches were applied to investigate whether Photobacterium damselae subsp. piscicida (Phdp) can directly sense and respond to growth conditions under different salinities, 0.85% and 3.5% NaCl concentrations, mimicking the osmotic conditions in host and marine water bodies, respectively. Proteins significantly altered were analyzed by two-dimensional gel electrophoresis (2-DE), liquid chromatography-electrospray ionization-quadrupole-time-of-flight tandem mass spectrometry (LC-ESI-Q-TOF MS/MS) and bioinformatics analysis, thus resulting in 16 outer membrane proteins (OMPs), 12 inner membrane proteins (IMPs), and 20 cytoplasmic proteins (CPs). Quantitative real-time PCR was also applied to monitor the mRNA expression level of these target proteins. Cluster of orthologous groups of protein (COG) analysis revealed that when shifting from 3.5% to 0.85% salinity, the majority of the up-regulated proteins were involved in posttranslational modification, protein turnover, and chaperones, while the down-regulated proteins were mainly related to energy production and conversion, compatible solutes (carbohydrates, amino acids and their derivatives) biogenesis and transport. Differentially expressed proteins identified in the current study could be used to elucidate the salt adaptation mechanisms of Phdp during their transition between host cells and the marine habitats.

Differential proteomics of monosodium urate crystals-induced inflammatory response in dissected murine air pouch membranes by iTRAQ technology.

The precipitation of monosodium urate crystals within joints triggers an acute inflammatory reaction that is the root cause of gout. The inflammation induced by the injection of MSU crystals into the murine air pouch for 1, 3, and 5 h was examined by iTRAQ-based proteomic profiling. The iTRAQ-labeled peptides were fractionated by SCX, basic-RP or solution-IEF, followed by LC-MS/MS analysis. A total of 951 proteins were quantified from the total combined fractions. Among them, 317 proteins exhibited a differential expression, compared to that of the controls at one time point or more. The majority of the differentially expressed proteins were found in the sample after a 5-h MSU treatment. Western blot revealed that the expression levels of cathelin-related antimicrobial peptide and S100A9 were positively correlated with the time-course treated with MSU. Further analysis of GeneGO pathway demonstrated that these differentially expressed proteins are primarily related to the immune-related complement system and the tricarboxylic acid cycle. Moreover, seven genes from the TCA cycle were found to be significantly downregulated at the transcriptional level and its correlation with gout and possible therapeutic applications are worth further investigation. Last, we found that pyruvate carboxylation could be potential targets for antigout treatment.

Quantitative analysis of prostate specific antigen isoforms using immunoprecipitation and stable isotope labeling mass spectrometry.

Prostate specific antigen (PSA) is a widely used serum marker for prostate cancer (PCa), but has limited specificity for distinguishing early PCa from benign prostatic hyperplasia (BPH). Recently, proPSAs, comprised of native proPSA, as well as truncated proPSA forms, [-2] proPSA, [-5] proPSA, and [-7] proPSA, have been shown to be better diagnostic targets than PSA for PCa. Stable isotope labeling-multiple reaction monitoring mass spectrometry (SIL/MRM-MS) has been frequently used to measure low-abundance biomarkers in tissues and biofluids, owing to its high sensitivity and specificity, simplicity, and multiplexing capability. In this study, we have developed and optimized a strategy using immunoprecipitation in conjunction with SIL/MRM-MS assay which is capable of sensitive and accurate quantification of proPSA in serum. Since serum and plasma are by far the most complex biological fluids, the immunoprecipitation workflow was optimized to achieve sufficient sensitivity, efficiencies of protein purification with immunoaffinity depletion were determined. The developed strategy can detect proPSA and PSA with a limit of detection (LOD) and limit of quantitation (LOQ) at nanogram per milliliter levels, corresponding to a concentration 6 orders-of-magnitude lower than the most abundant serum proteins. Furthermore, the simultaneous measurement of multiple biomarkers, including the mature and precursor forms of PSA, can be achieved in a single multiplexed analysis using LC/MRM-MS. The strategy demonstrated here provides an attractive alternative to ELISAs or RIAs for the reliably measurement of proPSA to improve the specificity of PCa diagnosis.

Lutein inhibits the migration of retinal pigment epithelial cells via cytosolic and mitochondrial Akt pathways (lutein inhibits RPE cells migration).

During the course of proliferative vitreoretinopathy (PVR), the retinal pigment epithelium (RPE) cells will de-differentiate, proliferate, and migrate onto the surfaces of the sensory retina. Several studies have shown that platelet-derived growth factor (PDGF) can induce migration of RPE cells via an Akt-related pathway. In this study, the effect of lutein on PDGF-BB-induced RPE cells migration was examined using transwell migration assays and Western blot analyses. We found that both phosphorylation of Akt and mitochondrial translocation of Akt in RPE cells induced by PDGF-BB stimulation were suppressed by lutein. Furthermore, the increased migration observed in RPE cells with overexpressed mitochondrial Akt could also be suppressed by lutein. Our results demonstrate that lutein can inhibit PDGF-BB induced RPE cells migration through the inhibition of both cytoplasmic and mitochondrial Akt activation.

Investigation of the effect of hyperglycemia on intracerebral hemorrhage by proteomic approaches.

Intracerebral hemorrhage (ICH) is associated with high mortality and disability, and hyperglycemia worsens the clinical and neurological outcomes of patients with ICH. In this study, we utilized proteomic approaches to investigate the role of hyperglycemia in ICH. Hyperglycemia was induced by intraperitoneal injection of streptozotocin (STZ) in adult Sprague-Dawley male rats; ICH was induced by stereotaxic infusion of collagenase/heparin into the right striatum. It was observed that the size of induced hemorrhage was significantly larger in the hyperglycemic group (n=6 in each group). On the first day after ICH, an apparent decrease in the bilateral grasp was also observed for the lesioned hyperglycemic rats compared with normoglycemic ones. When employing 2-DE and MS to examine the proteomes of perihematomal and control regions in individual hyperglycemic and normoglycemic rats, eight differentially expressed protein targets were identified. Most noteworthy, in response to ICH significant increase of albumin was ubiquitously observed in the brains of normoglycemic rats but not in the brains of hyperglycemic rats. Coincidentally, more significant neuronal apoptosis were found in the perihematomal regions of hyperglycemic rats. These observations described suggest the protection role of albumin in acute stage of ICH, which may be dependent on different blood sugar levels.

IL-6 augmented motility of airway epithelial cell BEAS-2B via Akt/GSK-3ß signaling pathway.

Cell migration plays a pivotal role in airway repair and remodeling involved in respiratory diseases such as asthma. Interleukin-6 (IL-6) and fascin-1 are involved in cell migration upon stimulation; however, the roles of IL-6 and fascin-1 in migration of airway epithelial cell remain sketchy. The present study was aimed to investigate influence of IL-6 on cell motility with emphasis on the association with fascin-1. Wound healing assay and transmigration assay were performed to examine effect of IL-6 on migration and invasiveness of human bronchial epithelial cell BEAS-2B. Level of mRNA expression was determined by RT-PCR and quantitative real-time RT-PCR (Q-PCR). Involvement of kinase and transcription factor signaling in IL-6-induced cell migration was investigated using immunoblot and specific inhibitors. IL-6 significantly augmented cell migration and invasiveness in parallel with elevated fascin-1 expression. Further investigation showed that IL-6 dose-dependently upregulated fascin-1 expression in both mRNA and protein levels. We showed that IL-6 activated Akt and inhibited glycogen synthase kinase-3ß (GSK-3ß), highly associating with fascin-1 mRNA expression. Additionally, IL-6-induced migration was significantly diminished by phosphatidyl inositol 3-phosphate kinase (PI3K) inhibitor (wortamannin) and ß-catenin inhibitor FH535. Moreover, LiCl and SB216763, inhibitors of GSK-3ß augmented cell migration as well as fascin-1 mRNA expression. Conclusively, these findings reveal that IL-6-induced migration of BEAS-2B cell may be attributed to activation of Akt, inhibition of GSK-3ß, and the associated increase of ß-catenin and fascin-1 expression, indicating an important role of Akt/GSK-3ß signaling and ß-catenin/fascin-1 in IL-6 associated airway remodeling.

The effects of gold nanoparticles in wound healing with antioxidant epigallocatechin gallate and α-lipoic acid.

Topical applications of antioxidant agents in cutaneous wounds have attracted much attention. Gold nanoparticles (AuNPs), epigallocatechin gallate (EGCG), and α-lipoic acid (ALA) were shown to have antioxidative effects and could be helpful in wound healing. Their effects in Hs68 and HaCaT cell proliferation and in mouse cutaneous wound healing were studied. Both the mixture of EGCG + ALA (EA) and AuNPs + EGCG + ALA (AuEA) significantly increased Hs68 and HaCaT proliferation and migration. Topical AuEA application accelerated wound healing on mouse skin. Immunoblotting of wound tissue showed significant increase of vascular endothelial cell growth factor and angiopoietin-1 protein expression, but no change of angiopoietin-2 or CD31 after 7 days. After AuEA treatment, CD68 protein expression decreased and Cu/Zn superoxide dismutase increased significantly in the wound area. In conclusion, AuEA significantly accelerated mouse cutaneous wound healing through anti-inflammatory and antioxidation effects. This study may support future studies using other antioxidant agents in the treatment of cutaneous wounds. FROM THE CLINICAL EDITOR: In this study, topically applied gold nanoparticles with epigallocatechin gallate and alpha-lipoic acid were studied regarding their effects in wound healing in cell cultures. Significant acceleration was demonstrated in wound healing in a murine model.

Adenine Combined with Cisplatin Promotes Anticancer Activity against Hepatocellular Cancer Cells through AMPK-Mediated p53/p21 and p38 MAPK Cascades.

Cisplatin has been widely used in cancer treatments. Recent evidence indicates that adenine has potential anticancer activities against various types of cancers. However, the effects of the combination of adenine and cisplatin on hepatocellular carcinoma (HCC) cells remain sketchy. Here, our objective was to elucidate the anticancer activity of adenine in combination with cisplatin in HCC cells and its mechanistic pathways. Cell viability and cell cycle progression were assessed by the SRB assay and flow cytometry, respectively. Apoptosis was demonstrated by PI/annexin V staining and flow cytometric analysis. Protein expression, signaling cascade, and mRNA expression were analyzed by Western blotting and quantitative RT-PCR, respectively. Our results showed that adenine jointly potentiated the inhibitory effects of cisplatin on the cell viability of SK-Hep1 and Huh7 cells. Further investigation showed that adenine combined with cisplatin induced higher S phase arrest and apoptosis in HCC cells. Mechanically, adenine induced AMPK activation, reduced mTOR phosphorylation, and increased p53 and p21 levels. The combination of adenine and cisplatin synergistically reduced Bcl-2 and increased PUMA, cleaved caspase-3, and PARP in HCC cells. Adenine also upregulated the mRNA expression of p53, p21, PUMA, and PARP, while knockdown of AMPK reduced the increased expression of these genes. Furthermore, adenine also induced the activation of p38 MAPK through AMPK signaling, and the inhibition of p38 MAPK reduced the apoptosis of HCC cells with exposure to adenine combined with cisplatin. Collectively, these findings reveal that the combination of adenine and cisplatin synergistically enhances apoptosis of HCC cells, which may be attributed to the AMPK-mediated p53/p21 and p38 MAPK cascades. It suggests that adenine may be a potential adjuvant for the treatment of HCC in combination with cisplatin.

Rosmarinic Acid Attenuates the Lipopolysaccharide-Provoked Inflammatory Response of Vascular Smooth Muscle Cell via Inhibition of MAPK/NF-κB Cascade.

Rosmarinic acid (RA) is a phenolic compound that has several bioactivities, such as anti-inflammatory and antioxidant activities. Here, we further investigate the anti-inflammatory effect of RA on rat A7r5 aortic smooth muscle cells with exposure to lipopolysaccharide (LPS). Our findings showed that low-dose RA (10-25 µM) did not influence the cell viability and morphology of A7r5 cells and significantly inhibited LPS-induced mRNA expression of the pro-inflammatory mediators TNFα, IL-8, and inducible NO synthase (iNOS). Consistently, RA reduced the production of TNFα, IL-8, and NO by A7r5 cells with exposure to LPS. Signaling cascade analysis showed that LPS induced activation of Erk, JNK, p38 mitogen-activated protein kinase (MAPK), and NF-κB, and RA treatments attenuated the activation of the three MAPKs and NF-κB. Moreover, cotreatment with RA and Erk, JNK, p38 MAPK, or NF-κB inhibitors further downregulated the mRNA expression of TNFα, IL-8, and iNOS, and decreased the production of TNFα, IL-8, and NO by A7r5 cells. Taken together, these findings indicate that RA may ameliorate the LPS-provoked inflammatory response of vascular smooth muscle cells by inhibition of MAPK/NF-κB signaling.

ENERGI-F703 gel, as a new topical treatment for diabetic foot and leg ulcers: A multicenter, randomized, double-blind, phase II trial.

Background: Diabetic foot and leg ulcers are a major cause of disability among patients with diabetes mellitus. A topical gel called ENERGI-F703, applied twice daily and with adenine as its active pharmaceutical ingredient, accelerated wound healing in diabetic mice. The current study evaluated the safety and efficacy of ENERGI-F703 for patients with diabetic foot and leg ulcers. Methods: This randomized, double-blind, multicenter, phase II trial recruited patients from eight medical centers in Taiwan. Patients with intractable diabetic foot and leg ulcers (Wagner Grade 1-3 without active osteomyelitis) were randomly assigned (2:1) to receive topical ENERGI-F703 gel or vehicle gel twice daily for 12 weeks or until complete ulcer closure. The investigator, enrolled patients and site personnel were masked to treatment allocation. Intention to treat (ITT) population and safety population were patient to primary analyses and safety analyses, respectively. Primary outcome was complete ulcer closure rate at the end of treatment. This trial is registered with ClinicalTrials.gov, number NCT02672436. Findings: Starting from March 15th, 2017 to December 26th, 2019, 141 patients were enrolled as safety population and randomized into ENERGI-F703 gel (n = 95) group or vehicle gel (n = 46) group. In ITT population, ENERGI-F703 (n = 90) and vehicle group showed ulcer closure rates of 36.7% (95% CI = 26.75% - 47.49%) and 26.2% (95% CI = 13.86% - 42.04%) with difference of 9.74 % (95 % CI = -6.74% - 26.23%) and 25% quartiles of the time to complete ulcer closure of 69 days and 84 days, respectively. There were 25 (26.3%) patients in ENERGI-F703 group and 11 (23.9%) patients in vehicle group experiencing serious adverse events and five deaths occurred during the study period, none of them related to the treatment. Interpretation: Our study suggests that ENERGI-F703 gel is a safe and well-tolerated treatment for chronic diabetic foot and leg ulcers. Further studies are needed to corroborate our findings in light of limitations. Funding: Energenesis Biomedical Co., Ltd.

Non-proteolytic house dust mite allergen, Der p 2, upregulated expression of tight junction molecule claudin-2 associated with Akt/GSK-3ß/ß-catenin signaling pathway.

Non-proteolytic group 2 allergen, Der p 2 (DP2) is known as a major allergen derived from house dust mite Dermatophagoides pteronyssinus.Paracellular epithelial barrier, being composed of a number of tight junction (TJ) molecules, plays pivotal roles in resistance of pathogen invading. However, whether DP2 affects epithelial TJ molecules is unclear. Therefore, we aimed to investigate the effects of DP2 on epithelial TJ molecules, and the mechanism by which expression of junction molecules is regulated by DP2. Cell cycle and mRNA expression of TJ proteins of lung alveolar cell A549 were analyzed by RT-PCR and flow cytometry. Level of claudin-2, subcellular distribution of b-catenin and kinase activation was determined using immunoblot. Our findings revealed that DP2 had no significant influence on cell cycle distribution but affected mRNA expression of TJ molecules including claudin-2, occludin, and ZO-1 in A549 cells. Our results showed that DP2 significantly elevated level of claudin-2 and increased expression and nuclear translocation of b-catenin. Moreover, DP2 enhanced the phosphorylation of glycogen synthase kinase-3b (GSK-3b) and its potential upstream regulator Akt. The DP2-induced claudin-2 expression was also suppressed by GSK-3b inhibitor (lithium chloride) and phosphatidyl inositol 3-phosphate kinase (PI3K) inhibitor (wortamannin). Taken together, these findings showed that DP2 increased claudin-2 expression and its cell surface distribution in A549 cells, which may attribute to phosphorylation of GSK-3b and Akt and the consequent increase and nuclear translocation of b-catenin. It is suggested that presence of DP2 may alter epithelial junction by regulating expression of TJ molecules.

Ocimum gratissimum Aqueous Extract Induces Apoptotic Signalling in Lung Adenocarcinoma Cell A549.

Ocimum gratissimum (OG) is widely used as a traditional herb for its antibacterial activity in Taiwan. Recently, antitumor effect of OG on breast cancer cell is also reported; however, the effects of OG on human pulmonary adenocarcinoma cell A549 remain unclear. Therefore, we aimed to investigate whether aqueous OG extract (OGE) affects viability of A549 cells and the signals induced by OGE in A549 cells. Cell viability assays revealed that OGE significantly and dose-dependently decreased the viability of A549 cell but not that of BEAS-2B cell. Morphological examination and DAPI staining indicated that OGE induced cell shrinkage and DNA condensation for A549 cells. Further investigation showed that OGE enhanced activation of caspase-3, caspase-9 and caspase-8 and increased protein level of Apaf-1 and Bak, but diminished the level of Bcl-2. Additionally, OGE inhibited the phosphorylation of extracellular signal-regulated kinase (ERK) yet enhanced the phosphorylation of c-Jun N-terminal kinase (JNK) and p38 MAP kinase (p38). In conclusion, our findings indicate that OGE suppressed the cell viability of A549 cells, which may result from the activation of apoptotic signaling and the inhibition of anti-apoptotic signaling, suggesting that OGE might be beneficial to lung carcinoma treatment.

Ocimum gratissimum Aqueous Extract Protects H9c2 Myocardiac Cells from H(2)O(2)-Induced Cell Apoptosis through Akt Signalling.

Increased cell death of cardiomyocyte by oxidative stress is known to cause dysfunction of the heart. O. gratissimum is one of the more well-known medicinal plants among the Ocimum species and widely used in treatment of inflammatory diseases. In this study, we hypothesized that aqueous extract of O. gratissimum leaf (OGE) may protect myocardiac cell H9c2 from oxidative injury by hydrogen peroxide (H(2)O(2)). Our results revealed that OGE pretreatment dose-dependently protects H9c2 cells from cell death when exposed to H(2)O(2). Additionally, DNA condensation induced by H(2)O(2) was also reduced by OGE pretreatment, suggesting that Ocimum gratissimum extract may attenuate H(2)O(2)-induced chromosome damage. Further investigation showed that OGE pretreatment inhibited H(2)O(2)-induced activation of caspase-3 and caspase-9, as well as H(2)O(2)-induced upregulation of proapoptotic Apaf-1 and the release of cytosolic cytochrome c, but has little effect on the activation of caspase-8. Additionally, OGE pretreatment significantly upregulated Bcl-2 expression and Akt phosphorylation, and slightly affected the phosphorylation of mitogen-activated protein kinases including p38 MAPK and JNK. Taken together, our findings revealed that Ocimum gratissimum extract effectively inhibited the mitochondrial pathway and upregulated Bcl-2 expression, which may be important in protecting H9c2 cells from H(2)O(2)-induced cell death.

Adenine Inhibits the Invasive Potential of DLD-1 Human Colorectal Cancer Cell via the AMPK/FAK Axis.

Tumor metastasis is a major cause of death of patients with colorectal cancer (CRC). Our previous findings show that adenine has antiproliferation activity against tumor cells. However, whether adenine reduces the invasiveness of DLD-1 and SW480 CRC cells has not been thoroughly explored. In this study, we aimed to explore the effects of adenine on the invasion potential of DLD-1 cells. Our findings showed that adenine at concentrations of ≤200 µM did not influence the cell viability of DLD-1 and SW480 CRC cells. By contrast, adenine reduced the migratory potential of the CRC cells. Moreover, it decreased the invasion capacity of the CRC cells in a dose-dependent manner. We further observed that adenine downregulated the protein levels of tissue plasminogen activator, matrix metalloproteinase-9, Snail, TWIST, and vimentin, but upregulated the tissue inhibitor of metalloproteinase-1 expression in DLD-1 cells. Adenine decreased the integrin αV level and reduced the activation of integrin-associated signaling components, including focal adhesion kinase (FAK), paxillin, and Src in DLD-1 cells. Further observations showed that adenine induced AMP-activated protein kinase (AMPK) activation and inhibited mTOR phosphorylation in DLD-1 cells. The knockdown of AMPK restored the reduced integrin αV level and FAK/paxillin/Src signaling inhibited by adenine in DLD-1 cells. Collectively, these findings reveal that adenine reduces the invasion potential of DLD-1 cells through the AMPK/integrin/FAK axis, suggesting that adenine may have anti-metastatic potential in CRC cells.