Yang Wan

Enhanced interaction between natural killer cells and lung cancer cells: involvement in gefitinib-mediated immunoregulation

BackgroundNatural killer (NK) cells can kill tumor cells in a non-MHC-restricted manner. However, cancer cells frequently escape from the attack of NK cells by multiple ways. In this study, we investigated the effect of gefitinib on the interaction between NK cells and lung cancer cells.Methods51Cr release assay, CD107a assay, and IFN-γ secretion assay were performed to detect the sensitivity of lung cancer cell lines A549 and H1975 to NK cells cytotoxicity in the presence of gefitinib. Human NK cells were co-cultured with A549 and H1975 cell lines in the presence of gefitinib. NKG2D ligands, ULBP1, ULBP2, MICA, and MHC-I on tumor cells, and NKG2D, NKp44 and NKp46 on NK cells were evaluated with flow cytometry. 51Cr release assay was performed when NKG2D antibody were added into the co-culture system. Expressions of stat3 and LC3 I/II on tumor cells were determined with western blot after co-cultured with NK cells. After treated with gefitinib, mannose-6-phosphate receptor (MPR) on H1975 cells was evaluated by flow cytometry. 51Cr release assay were performed when MPR antagonist were used.ResultsGefitinib increased cytotoxicity of NK cells to human lung cancer H1975 cells with EGFR L858R + T790M mutations, while not in A549 cells with wild type EGFR. Gefitinib could block the immune escape by up-regulating the expression of NKG2D ligands ULBP1, ULBP2 or MICA on tumor cells and NKG2D on NK cells in the co-culture system. Gefitinib and NK cells up-regulated MHC-I expression in A549 while not in H1975 cells. NKG2D antibody blocked the enhanced NK cytotoxicity by gefitinib. The combination of NK cells and gefitinib could significantly down-regulate stat3 expression. Furthermore, NK cells-mediated tumor cell autophagy was observed in A549 cells while not in H1975 cells. Notably, gefitinib increased autophagy and MPR expression in H1975 cells, which improved the sensitivity to NK cell-based immunotherapy.ConclusionsGefitinib greatly enhanced NK cell cytotoxicity to lung cancer cells with EGFR L858R + T790M resistance mutation. Combination of EGFR tyrokinase inhibitors and NK cells adoptive immunotherapy may represent a potentially effective strategy for patients with non-small cell lung cancer.

Inhibitory effect of liposomal quercetin on acute hepatitis and hepatic fibrosis induced by concanavalin A

Immune response plays an important role in the development of hepatic fibrosis. In the present study, we investigated the effects of quercetin on hepatitis and hepatic fibrosis induced by immunological mechanism. In the acute hepatitis model, quercetin (2.5 mg/kg) was injected iv into mice 30 min after concanavalin A (Con A) challenge. Mice were sacrificed 4 or 24 h after Con A injection, and aminotransferase tests and histopathological sections were performed. Treatment with quercetin significantly decreased the levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST). Consistent with this observation, treatment with quercetin markedly attenuated the pathologic changes in the liver. A hepatic fibrosis model was also generated in mice by Con A challenge once a week for 6 consecutive weeks. Mice in the experimental group were treated with daily iv injections of quercetin (0.5 mg/kg). Histopathological analyses revealed that treatment with quercetin markedly decreased collagen deposition, pseudolobuli development, and hepatic stellate cells activation. We also examined the effects of quercetin on the nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) and transforming growth factor beta (TGF-β) pathways by immunohistochemistry and real-time reverse transcriptase-polymerase chain reaction (RT-PCR). NF-κB and TGF-β production was decreased after treatment with quercetin, indicating that the antifibrotic effect of quercetin is associated with its ability to modulate NF-κB and TGF-β production. These results suggest that quercetin may be an effective therapeutic strategy in the treatment of patients with liver damage and fibrosis.

In Vitro and In Vivo Activities of Antimicrobial Peptides Developed Using an Amino Acid-Based Activity Prediction Method

ABSTRACT To design and discover new antimicrobial peptides (AMPs) with high levels of antimicrobial activity, a number of machine-learning methods and prediction methods have been developed. Here, we present a new prediction method that can identify novel AMPs that are highly similar in sequence to known peptides but offer improved antimicrobial activity along with lower host cytotoxicity. Using previously generated AMP amino acid substitution data, we developed an amino acid activity contribution matrix that contained an activity contribution value for each amino acid in each position of the model peptide. A series of AMPs were designed with this method. After evaluating the antimicrobial activities of these novel AMPs against both Gram-positive and Gram-negative bacterial strains, DP7 was chosen for further analysis. Compared to the parent peptide HH2, this novel AMP showed broad-spectrum, improved antimicrobial activity, and in a cytotoxicity assay it showed lower toxicity against human cells. The in vivo antimicrobial activity of DP7 was tested in a Staphylococcus aureus infection murine model. When inoculated and treated via intraperitoneal injection, DP7 reduced the bacterial load in the peritoneal lavage solution. Electron microscope imaging and the results indicated disruption of the S. aureus outer membrane by DP7. Our new prediction method can therefore be employed to identify AMPs possessing minor amino acid differences with improved antimicrobial activities, potentially increasing the therapeutic agents available to combat multidrug-resistant infections.

PNAS-4, an Early DNA Damage Response Gene, Induces S Phase Arrest and Apoptosis by Activating Checkpoint Kinases in Lung Cancer Cells.

Background: Elevated PNAS-4 induces S phase arrest and apoptosis in vitro and inhibits tumor growth in vivo. Results: PNAS-4 activates Chk1/2 to cause inhibition of the Cdc25A-CDK2-cyclin E/A pathway, causing S phase arrest and apoptosis. Conclusion: Activation of Chk1/2 is a determinant of S phase arrest and apoptosis. Significance: We provide a novel action mechanism for PNAS-4 as a potential therapeutic target for lung cancer. PNAS-4, a novel pro-apoptotic gene, was activated during the early response to DNA damage. Our previous study has shown that PNAS-4 induces S phase arrest and apoptosis when overexpressed in A549 lung cancer cells. However, the underlying action mechanism remains far from clear. In this work, we found that PNAS-4 expression in lung tumor tissues is significantly lower than that in adjacent lung tissues; its expression is significantly increased in A549 cells after exposure to cisplatin, methyl methane sulfonate, and mitomycin; and its overexpression induces S phase arrest and apoptosis in A549 (p53 WT), NCI-H460 (p53 WT), H526 (p53 mutation), and Calu-1 (p53−/−) lung cancer cells, leading to proliferation inhibition irrespective of their p53 status. The S phase arrest is associated with up-regulation of p21Waf1/Cip1 and inhibition of the Cdc25A-CDK2-cyclin E/A pathway. Up-regulation of p21Waf1/Cip1 is p53-independent and correlates with activation of ERK. We further showed that the intra-S phase checkpoint, which occurs via DNA-dependent protein kinase-mediated activation of Chk1 and Chk2, is involved in the S phase arrest and apoptosis. Gene silencing of Chk1/2 rescues, whereas that of ATM or ATR does not affect, S phase arrest and apoptosis. Furthermore, human PNAS-4 induces DNA breaks in comet assays and γ-H2AX staining. Intriguingly, caspase-dependent cleavage of Chk1 has an additional role in enhancing apoptosis. Taken together, our findings suggest a novel mechanism by which elevated PNAS-4 first causes DNA-dependent protein kinase-mediated Chk1/2 activation and then results in inhibition of the Cdc25A-CDK2-cyclin E/A pathway, ultimately causing S phase arrest and apoptosis in lung cancer cells.

Ursolic acid attenuates lipopolysaccharide-induced acute lung injury in a mouse model

AIM To assess whether ursolic acid (UA) can attenuate lipopolysachharide (LPS)-induced acute lung injury and improve the survival time in a mouse model. MATERIALS & METHODS The mice were challenged with LPS and survival time was monitored from 0-96 h after LPS treatment. TNF-α, IL-6, IL-1β, HMGB1, nitric oxide (NO) and IL-10 concentration in serum were measured by ELISA. Myeloperoxidase activity, malondialdehyde, lung wet:dry weight ratio and lung permeability in lung tissues were detected. NF-κB, HMGB1 and inducible NO synthase in the lungs were detected by western blot. RESULTS UA markedly rescued lethality, improved survival time and lung pathological changes, inhibited TNF-α, IL-6, IL-1β, HMGB1 and NO, and increased IL-10 expression. In addition, UA can also decrease myeloperoxidase, malondialdehyde, lung wet:dry weight ratio and lung permeability. UA attenuated NF-κB, HMGB1 and inducible NO synthase protein expression in the lungs. CONCLUSION The results suggest that UA is capable of improving survival time and LPS-induced acute lung injury. UA has a potentially therapeutic role in septic shock.

Genetically modified human placenta‑derived mesenchymal stem cells with FGF‑2 and PDGF‑BB enhance neovascularization in a model of hindlimb ischemia.

Ischemic diseases represent a challenging worldwide health burden. The current study investigated the therapeutic potential of genetically modified human placenta-derived mesenchymal stem cells (hPDMSCs) with basic fibroblast growth factor (FGF2) and platelet-derived growth factor-BB (PDGF-BB) genes in hindlimb ischemia. Mesenchymal stem cells obtained from human term placenta were transfected ex vivo with adenoviral bicistronic vectors carrying the FGF2 and PDGF-BB genes (Ad-F-P). Unilateral hindlimb ischemia was surgically induced by excision of the right femoral artery in New Zealand White rabbits. Ad-F-P genetically modified hPDMSCs, Ad-null (control vector)-modified hPDMSCs, unmodified hPDMSCs or media were intramuscularly implanted into the ischemic limbs 7 days subsequent to the induction of ischemia. Four weeks after cell therapy, angiographic analysis revealed significantly increased collateral vessel formation in the Ad-F-P-hPDMSC group compared with the control group. Histological examination revealed markedly increased capillary and arteriole density in the Ad-F-P-hPDMSC group. The xenografted hPDMSCs survived in the ischemic tissue for at least 4 weeks subsequent to cell therapy. The current study demonstrated that the combination of hPDMSC therapy with FGF2 and PDGF-BB gene therapy effectively induced collateral vessel formation and angiogenesis, suggesting a novel strategy for therapeutic angiogenesis.

Antiangiogenic Therapy Using Sunitinib Combined with Rapamycin Retards Tumor Growth But Promotes Metastasis

BACKGROUND: This study investigated the synergistic effect of sunitinib and rapamycin on tumor growth and metastasis in murine breast cancer model. METHODS: The synergistic antitumor effect of sunitinib and rapamycin on tumor growth and metastasis was investigated. Myeloid-derived suppressor cells (MDSCs) in spleens and lungs were assessed. Tumor hypoxia, vessel density and micrometastasis were evaluated. Versican, indoleamine 2,3-dioxygenase (IDO), arginase 1, interleukin-6 (IL-6), IL-10, and transforming growth factor β (TGF-β) in the lungs and tumors were examined. IL-6 and TGF-β in the blood were evaluated. RESULTS: Synergism between sunitinib and rapamycin on tumor growth was observed. Sunitinib plus rapamycin reduced splenomegaly, MDSCs in spleens and lungs, and microvessel density in tumor microenvironment, while exacerbated hypoxia and promoted cancer lung metastasis. Sunitinib plus rapamycin markedly induced versican, IDO, arginase 1, IL-6, and TGF-β expression in the lungs, whereas it reduced IDO and IL-10 expression in the primary tumor tissues. IL-6 levels in the circulation were increased after rapamycin and combination therapies. CONCLUSIONS: The combination of sunitinib plus rapamycin reduced the tumor growth but promoted tumor metastasis. This study warrants that further mTOR inhibition treatment should be closely watched in clinical setting, especially combined with antiangiogenic therapy.

Suppression of peritoneal tumorigenesis by placenta-derived mesenchymal stem cells expressing endostatin on colorectal cancer.

MSCs-based therapy for cancer is a relatively new but rapidly growing area of research. Human term placenta, an attractive source of MSCs (PMSCs), appears to have great advantage due to its easy access without invasive procedures, its lack of ethical issues and its high-throughput and young age. In the present study, we isolated MSCs from placenta and characterized their morphology and differentiation capacities. We next investigated the underlying antitumor effects and the potential mechanism of PMSCs to express endostatin using adenoviral transduction (Ad-Endo) in a colorectal peritoneal carcinomatosis (CRPC) mouse model. For in vitro experiments, the migratory potential of Ad-Endo-PMSCs towards tumor cells was demonstrated using a double-chamber assay, and the anti-angiogenesis ability of endostatin from engineered PMSCs was evaluated using the tube formation assay. For the in vivo study, mice harboring CT26 colorectal cancer indicated a significant reduction in tumor nodules and a prolongation of survival following Ad-Endo-PMSCs therapy. These observations were associated with significantly decreased tumor cell proliferation and blood vessel counts as well as increased tumor cell apoptosis. These data suggested the potential of PMSCs-based gene therapy for the targeted delivery of therapeutic proteins in cancer.

NOXA-Induced Alterations in the Bax/Smac Axis Enhance Sensitivity of Ovarian Cancer Cells to Cisplatin

Ovarian cancer is the most common cause of death from gynecologic malignancy. Deregulation of p53 and/or p73-associated apoptotic pathways contribute to the platinum-based resistance in ovarian cancer. NOXA, a pro-apoptotic BH3-only protein, is identified as a transcription target of p53 and/or p73. In this study, we found that genetic variants of Bcl-2 proteins exist among cisplatin-sensitive and -resistant ovarian cancer cells, and the responses of NOXA and Bax to cisplatin are regulated mainly by p53. We further evaluated the effect of NOXA on cisplatin. NOXA induced apoptosis and sensitized A2780s and SKOV3 cells to cisplatin in vitro and in vivo. The effects were mediated by elevated Bax expression, enhanced caspase activation, release of Cyt C and Smac into the cytosol. Furthermore, gene silencing of Bax or Smac significantly attenuated NOXA and/or cisplatin-induced apoptosis in chemosensitive A2780s cells, whereas overexpression of Bax or addition of Smac-N7 peptide significantly increased NOXA and/or cisplatin-induced apoptosis in chemoresistant SKOV3 cells. To our knowledge, these data suggest a new mechanism by which NOXA chemosensitized ovarian cancer cells to cisplatin by inducing alterations in the Bax/Smac axis. Taken together, our findings show that NOXA is potentially useful as a chemosensitizer in ovarian cancer therapy.

Effective inhibition of melanoma tumorigenesis and growth via a new complex vaccine based on NY-ESO-1-alum-polysaccharide-HH2.

BackgroundA safe and effective adjuvant plays an important role in the development of a vaccine. However, adjuvants licensed for administration in humans remain limited. Here, for the first time, we developed a novel combination adjuvant alum-polysaccharide-HH2 (APH) with potent immunomodulating activities, consisting of alum, polysaccharide of Escherichia coli and the synthetic cationic innate defense regulator peptide HH2.MethodsThe adjuvant effects of APH were examined using NY-ESO-1 protein-based vaccines in prophylactic and therapeutic models. We further determined the immunogenicity and anti-tumor effect of NY-ESO-1-APH (NAPH) vaccine using adoptive cellular/serum therapy in C57/B6 and nude mice. Cell-mediated and antibody-mediated immune responses were evaluated.ResultsThe APH complex significantly promoted antigen uptake, maturation and cross-presentation of dendritic cells and enhanced the secretion of TNF-α, MCP-1 and IFN-γ by human peripheral blood mononuclear cells compared with individual components. Vaccination of NAPH resulted in significant tumor regression or delayed tumor progression in prophylactic and therapeutic models. In addition, passive serum/cellular therapy potently inhibited tumor growth of NY-ESO-1-B16. Mice treated with NAPH vaccine produced higher antibody titers and greater antibody-dependent/independent cellular cytotoxicity. Therefore, NAPH vaccination effectively stimulated innate immunity, and boosted both arms of the adaptive humoral and cellular immune responses to suppress tumorigenesis and growth of melanoma.ConclusionsOur study revealed the potential application of APH complex as a novel immunomodulatory agent for vaccines against tumor refractory and growth.