Effects and mechanism of Qingke Pingchuan granules against influenza virus infection.

Qingke Pingchuan granules (QPGs), which contain Houttuynia cordata Thunb, Fritillaria cirrhosa, fired licorice, and fired bitter almonds, among other components, can clear heat and ventilate the lungs, relieving cough and asthma. Clinically, QPGs are mainly used to treat cough, asthma, fever and other discomforts caused by acute or chronic bronchitis. In this study, the antiviral activity of QPGs against respiratory syncytial virus (RSV), influenza A virus A/FM/1/47 (H1N1), oseltamivir-resistant H1N1, A/Beijing/32/92 (H3N2), Sendai virus, and human adenovirus type 3 in Hep-2 or MDCK cells was evaluated using the CCK-8 method, and the cytotoxicity of QPGs to these two cell lines was tested. The effect of QPGs on mice infected with influenza A virus A/FM/1/47 (H1N1) was evaluated by measuring body weight, survival time, and survival rate, as well as virus titers and lesions in the lungs and levels of inflammatory factors in serum. In addition, the expression of TLR-7-My88-NF-κB signaling pathway-related proteins in lung tissues was analyzed by Western blotting and qRT-PCR. The results showed that QPGs had a potent inhibitory effect on the six viruses tested in vitro. Interestingly, QPGs also displayed particularly pronounced antiviral activity against H1N1-OC, similar to that of oseltamivir, a well-known antiviral drug. QPGs effectively protected mice from infection by H1N1, as indicated by significantly increased body weights, survival times, and survival rates and reduced lung virus titers of inflammatory factors and lung tissue injury. The levels of TLR-7-MyD88-NF-κB-pathway-related proteins in the lung tissue of infected mice were found to be decreased after QPG treatment, thereby alleviating lung injury caused by excessive release of inflammatory factors. Taken together, these findings indicate that QPGs have satisfactory activity against influenza virus infection.

Inhibiting autophagy enhanced mitotic catastrophe-mediated anticancer immune responses by regulating the cGAS-STING pathway.

Given the limitations of the response rate and efficacy of immune checkpoint inhibitors (ICIs) in clinical applications, exploring new therapeutic strategies for cancer immunotherapy is necessary. We found that 5-(3,4,5-trimethoxybenzoyl)-4-methyl-2-(p-tolyl)imidazole (BZML), a microtubule-targeting agent, exhibited potent anticancer activity by inducing mitotic catastrophe in A549/Taxol and L929 cells. Nuclear membrane disruption and nuclease reduction provided favorable conditions for cGAS-STING pathway activation in cells with mitotic catastrophe. Similar results were obtained in paclitaxel-, docetaxel- and doxorubicin-induced mitotic catastrophe in various cancer cells. Notably, the surface localization of CALR and MHC-I and the release of HMGB1 were also significantly increased in cells with mitotic catastrophe, but not in apoptotic cells, suggesting that mitotic catastrophe is an immunogenic cell death. Furthermore, activated CD8+T cells enhanced the anticancer effects originating from mitotic catastrophe induced by BZML. Inhibiting the cGAS-STING pathway failed to affect BZML-induced mitotic catastrophe but could inhibit mitotic catastrophe-mediated anticancer immune effects. Interestingly, the expression of p-TBK1 first increased and then declined; however, autophagy inhibition reversed the decrease in p-TBK1 expression and enhanced mitotic catastrophe-mediated anticancer immune effects. Collectively, the inhibition of autophagy can potentiate mitotic catastrophe-mediated anticancer immune effects by regulating the cGAS-STING pathway, which explains why the anticancer immune effects induced by chemotherapeutics have not fully exerted their therapeutic efficacy in some patients and opens a new area of research in cancer immunotherapy.

hsdSA regulated extracellular vesicle-associated PLY to protect Streptococcus pneumoniae from macrophage killing via LAPosomes.

IMPORTANCE: S. pneumoniae is a major human pathogen that undergoes a spontaneous and reversible phase variation that allows it to survive in different host environments. Interestingly, we found hsdSA , a gene that manipulated the phase variation, promoted the survival and replication of S. pneumoniae in macrophages by regulating EV production and EV-associated PLY. More importantly, here we provided the first evidence that higher EV-associated PLY (produced by D39) could form LAPosomes that were single membrane compartments containing S. pneumoniae, which are induced by integrin ß1/NOX2/ROS pathway. At the same time, EV-associated PLY increased the permeability of lysosome membrane and induced an insufficient acidification to escape the host killing, and ultimately prolonged the survival of S. pneumoniae in macrophages. In contrast, lower EV-associated PLY (produced by D39ΔhsdSA ) activated ULK1 recruitment to form double-layered autophagosomes to eliminate bacteria.

Perspectives and mechanisms for targeting mitotic catastrophe in cancer treatment.

Mitotic catastrophe is distinct from other cell death modes due to unique nuclear alterations characterized as multi and/or micronucleation. Mitotic catastrophe is a common and virtually unavoidable consequence during cancer therapy. However, a comprehensive understanding of mitotic catastrophe remains lacking. Herein, we summarize the anticancer drugs that induce mitotic catastrophe, including microtubule-targeting agents, spindle assembly checkpoint kinase inhibitors, DNA damage agents and DNA damage response inhibitors. Based on the relationships between mitotic catastrophe and other cell death modes, we thoroughly evaluated the roles played by mitotic catastrophe in cancer treatment as well as its advantages and disadvantages. Some strategies for overcoming its shortcomings while fully utilizing its advantages are summarized and proposed in this review. We also review how mitotic catastrophe regulates cancer immunotherapy. These summarized findings suggest that the induction of mitotic catastrophe can serve as a promising new therapeutic approach for overcoming apoptosis resistance and strengthening cancer immunotherapy.

Peptide MSI-1 inhibited MCR-1 and regulated outer membrane vesicles to combat immune evasion of Escherichia coli.

Polymyxin resistance is conferred by MCR-1 (mobile colistin resistance 1)-induced lipopolysaccharide (LPS) modification of G- bacteria. However, the peptide MSI-1 exerts potent antimicrobial activity against mcr-1-carrying bacteria. To further investigate the potential role of MCR-1 in improving bacterial virulence and facilitating immune evasion, and the immunomodulatory effect of peptide MSI-1, we first explored outer membrane vesicle (OMV) alterations of mcr-1-carrying bacteria in the presence and absence of sub-MIC MSI-1, and host immune activation during bacterial infection and OMV stimulation. Our results demonstrated that LPS remodelling induced by MCR-1 negatively affected OMV formation and protein cargo by E. coli. In addition, MCR-1 diminished LPS-stimulated pyroptosis but facilitated mitochondrial dysfunction, further aggravating apoptosis in macrophages induced by OMVs of E. coli. Similarly, TLR4-mediated NF-κB activation was markedly alleviated once LPS was modified by MCR-1. However, peptide MSI-1 at the sub-MIC level inhibited the expression of MCR-1, further partly rescuing OMV alteration and attenuation of immune responses in the presence of MCR-1 during both infection and OMV stimulation, which can be exploited for anti-infective therapy.

Cbf-14, a cationic peptide derived from cathelin-domain, exhibits anti-inflammation activity via inhibiting PI3K- Akt /ROS/ NF-κB signaling pathway.

Cbf-14 with the sequence RLLRKFFRKLKKSV, is an effective antimicrobial peptide derived from a cathelin-like domain. Previous reports have demonstrated that Cbf-14 not only exerts antimicrobial activity against penicillin-resistant bacteria but also alleviates bacterial-induced inflammation in E. coli BL21 (DE3)-NDM-1-infected mice. In this article, we demonstrated that Cbf-14 can effectively reduce RAW 264.7 intracellular infection caused by clinical strain E. coli and alleviate the inflammatory response of cells and improve cell survival after infection. Therefore, we established the LPS-stimulated RAW 264.7 cell inflammation model to uncover the molecular mechanisms of the peptide Cbf-14 in anti-inflammatory activity. The results reveal that Cbf-14 can decrease LPS-induced ROS secretion by blocking the membrane translocation of p47-phox subunits and suppressing p47-phox protein phosphorylation. Meanwhile, this peptide can down-regulate the over-expression of iNOS, and finally inhibit the NO excessive secretion from RAW 264.7 macrophages stimulated by LPS. Moreover, Cbf-14 also down-regulates the expression levels of p-IκB and p-p65 and inhibits the nuclear translocation of NF-κB through blocking MAPK- and/or PI3K-Akt signaling pathways. Overall, Cbf-14 exhibits anti-inflammatory activity through inhibiting NF-κB activity and ROS production via PI3K- Akt signaling pathway.

An active domain SA-2 derived from cystatin-SA, and its antifungal activity.

Infections induced by fungi, especially the drug-resistant fungi, are difficult clinical problems. Conventional antifungal treatment is effective but due to resistance, treatment failure, and treatment-related toxicity, there is a need for new antifungal drugs. In this study, SA-2 (YYRRLLRVLRRRW) was derived from Cystatin-SA, a saliva protein with a molecular weight of 14 kDa. Meanwhile, the structure-activity of SA-2 and its mutants was also studied. We detected the antimicrobial activity and cytotoxicity of SA-2 and found that SA-2 had a low cytotoxicity toward mammalian cells but a good inhibitory effect on Candida albicans (C. albicans) and Cryptococcus neoformans (C. neoformans), with MIC values of 16-64 µg/mL and 8-32 µg/mL, respectively. Interestingly, SA-2 effectively killed fluconazole-resistant C. neoformans and C. albicans within 12 h. This antifungal activity against fluconazole-resistant fungi was comparable to that of amphotericin B. In addition, the C. neoformans-infected mice model was established to evaluate the anti-infective activity of SA-2 in vivo. Results showed that SA-2 significantly reduced the counts of fungi in lung and brain tissues to protect fluconazole-resistant C. neoformans-infected mice from death without changing mice body weights. Moreover, the dramatically increased pro-inflammatory cytokines TNF-α, IL-6 and IL-1ß induced by intranasal infection of C. neoformans could be obviously declined due to the treatment of SA-2, which may be attributed to the elimination of C. neoformans in time in the infected tissue. For the mode of actions underlying SA-2 against C. neoformans, we found that the cationic peptide SA-2 could adhere to the negatively charged fungal cell membrane to increase the surface potential of C. neoformans in a dose-dependent manner, and finally disrupted the integrity of fungal cell membrane, reflecting as a 60% positive rate of propidium iodide uptake of C. neoformans cells after SA-2 (4 × MIC) treatment. Our study indicated that SA-2 has the potential to develop as a new therapeutic agent against infection induced by drug-resistant fungi.

The multiple effects of REG1 deletion and SNF1 overexpression improved the production of S-adenosyl-L-methionine in Saccharomyces cerevisiae.

BACKGROUND: Saccharomyces cerevisiae is often used as a cell factory for the production of S-adenosyl-L-methionine (SAM) for diverse pharmaceutical applications. However, SAM production by S. cerevisiae is negatively influenced by glucose repression, which is regulated by a serine/threonine kinase SNF1 complex. Here, a strategy of alleviating glucose repression by deleting REG1 (encodes the regulatory subunit of protein phosphatase 1) and overexpressing SNF1 (encodes the catalytic subunit of the SNF1 complex) was applied to improve SAM production in S. cerevisiae. SAM production, growth conditions, glucose consumption, ethanol accumulation, lifespan, glycolysis and amino acid metabolism were analyzed in the mutant strains. RESULTS: The results showed that the multiple effects of REG1 deletion and/or SNF1 overexpression exhibited a great potential for improving the SAM production in yeast. Enhanced the expression levels of genes involved in glucose transport and glycolysis, which improved the glucose utilization and then elevated the levels of glycolytic intermediates. The expression levels of ACS1 (encoding acetyl-CoA synthase I) and ALD6 (encoding aldehyde dehydrogenase), and the activity of alcohol dehydrogenase II (ADH2) were enhanced especially in the presence of excessive glucose levels, which probably promoted the conversion of ethanol in fermentation broth into acetyl-CoA. The gene expressions involved in sulfur-containing amino acids were also enhanced for the precursor amino acid biosynthesis. In addition, the lifespan of yeast was extended by REG1 deletion and/or SNF1 overexpression. As expected, the final SAM yield of the mutant YREG1ΔPSNF1 reached 8.28 g/L in a 10-L fermenter, which was 51.6% higher than the yield of the parent strain S. cerevisiae CGMCC 2842. CONCLUSION: This study showed that the multiple effects of REG1 deletion and SNF1 overexpression improved SAM production in S. cerevisiae, providing new insight into the application of the SNF1 complex to abolish glucose repression and redirect carbon flux to nonethanol products in S. cerevisiae.

Characterization of structurally related peptide impurities using HPLC-QTOF-MS/MS: application to Cbf-14, a novel antimicrobial peptide.

Cbf-14 (RLLRKFFRKLKKSV), a designed antimicrobial peptide derived from the cathelicidin family, is effective against drug-resistant bacteria. Structurally related peptide impurities in peptide medicines probably have side effects or even toxicity, thus impurity profiling research during the entire production process is indispensable. In this study, a simple liquid chromatography-high-resolution mass spectrometry (LC-HRMS) method using a quadrupole time-of-flight (Q-TOF) mass spectrometer was developed for separation, identification, and characterization of structurally related peptide impurities in Cbf-14. A total of one process-related impurity and thirty-two degradation products were identified, and seven of them have been synthesized and confirmed. These impurities have not been declared in custom synthetic peptides. The degradation products were divided into five categories: fifteen Cbf-14 hydrolysates, five Cbf-14 isomers, four acetyl-Cbf-14 isomers, two aldimine derivatives, and six oxidized impurities. Combined with the peptide synthesis and the stress-testing studies, the origins and the formation mechanisms of these impurities were elucidated, which provides a unique insight for the follow-up quality study of Cbf-14 and other peptide products.

Autophagy and cancer treatment: four functional forms of autophagy and their therapeutic applications.

Cancer is the leading cause of death worldwide. Drugs play a pivotal role in cancer treatment, but the complex biological processes of cancer cells seriously limit the efficacy of various anticancer drugs. Autophagy, a self-degradative system that maintains cellular homeostasis, universally operates under normal and stress conditions in cancer cells. The roles of autophagy in cancer treatment are still controversial because both stimulation and inhibition of autophagy have been reported to enhance the effects of anticancer drugs. Thus, the important question arises as to whether we should try to strengthen or suppress autophagy during cancer therapy. Currently, autophagy can be divided into four main forms according to its different functions during cancer treatment: cytoprotective (cell survival), cytotoxic (cell death), cytostatic (growth arrest), and nonprotective (no contribution to cell death or survival). In addition, various cell death modes, such as apoptosis, necrosis, ferroptosis, senescence, and mitotic catastrophe, all contribute to the anticancer effects of drugs. The interaction between autophagy and these cell death modes is complex and can lead to anticancer drugs having different or even completely opposite effects on treatment. Therefore, it is important to understand the underlying contexts in which autophagy inhibition or activation will be beneficial or detrimental. That is, appropriate therapeutic strategies should be adopted in light of the different functions of autophagy. This review provides an overview of recent insights into the evolving relationship between autophagy and cancer treatment.

Survivin suppression heightens BZML-induced mitotic catastrophe to overcome multidrug resistance by removing therapy-induced senescent A549/Taxol cells.

Mitotic catastrophe (MC) is a newly identified type of anticancer mechanism for multidrug resistance (MDR) prevention. However, the long cellular death process resulting from MC is not beneficial for anticancer treatment. BZML is a novel colchicine-binding site inhibitor which can overcome MDR by inducing MC; however, BZML-induced MC cells underwent a long cellular death process. Thus, to improve anticancer therapies based on drug-induced MC, BZML-induced MC was served as a model to further study the underlying molecular mechanisms in the process of MC. Here, BZML could induce p53-dependent senescence in A549/Taxol cells, a MDR cell line. This senescence was a secondary effect of MC in overcoming MDR. During MC, BZML-induced destruction of protein-degradation system contributed not only to an increase of p53 protein but also to the accumulation of survivin in nucleus of A549/Taxol cells. Importantly, the nuclear accumulation of survivin was not the inducer but the result of BZML-induced MC, and it promoted the survival of senescent cells. Moreover, it provided additional vulnerability and critical opportunities for sequentially applied therapies. Further, targeting survivin with YM155 accelerated the death of MC cells by timely eliminating therapy-induced senescent cells and strengthening the efficiency of BZML in overcoming MDR in A549/Taxol cells. Collectively, nuclear accumulation of survivin delayed cellular death during MC by promoting the survival of BZML-induced senescent A549/Taxol cells. Moreover, "one-two punch" approach to cancer treatment based on combination therapy with YM155 for survivin suppression might be a new strategy for potentiating MC to overcome MDR.

Structural analysis and binding sites of inhibitors targeting the CD47/SIRPα interaction in anticancer therapy.

Cluster of differentiation 47 (CD47)/signal regulatory protein alpha (SIRPα) is a negative innate immune checkpoint signaling pathway that restrains immunosurveillance and immune clearance, and thus has aroused wide interest in cancer immunotherapy. Blockade of the CD47/SIRPα signaling pathway shows remarkable antitumor effects in clinical trials. Currently, all inhibitors targeting CD47/SIRPα in clinical trials are biomacromolecules. The poor permeability and undesirable oral bioavailability of biomacromolecules have caused researchers to develop small-molecule CD47/SIRPα pathway inhibitors. This review will summarize the recent advances in CD47/SIRPα interactions, including crystal structures, peptides and small molecule inhibitors. In particular, we have employed computer-aided drug discovery (CADD) approaches to analyze all the published crystal structures and docking results of small molecule inhibitors of CD47/SIRPα, providing insight into the key interaction information to facilitate future development of small molecule CD47/SIRPα inhibitors.

QTMP, a Novel Thiourea Polymer, Causes DNA Damage to Exert Anticancer Activity and Overcome Multidrug Resistance in Colorectal Cancer Cells.

Colorectal cancer (CRC) is one of the most common malignancies, and multidrug resistance (MDR) severely restricts the effectiveness of various anticancer drugs. Therefore, the development of novel anticancer drugs for the treatment of CRC patients with MDR is necessary. Quaternized thiourea main-chain polymer (QTMP) is a self-assembled nanoparticle with good water solubility. Notably, QTMP is not a P-glycoprotein (P-gp) substrate, and it exhibits potent cytotoxic activity against CRC cells, including HCT116/DDP and P-gp-mediated multidrug-resistant Caco2 cells. QTMP also exhibits a strong anticancer activity against SW480 cells in vivo. Interestingly, reactive oxygen species (ROS) and reactive nitrogen species (RNS) production were increased in a concentration-dependent manner in QTMP-treated HCT116, SW480 and Caco2 cells. Importantly, QTMP causes DNA damage in these CRC cells via direct insertion into the DNA or regulation of ROS and/or RNS production. QTMP also induces caspase-dependent apoptosis via overproduction of ROS and RNS. Therefore, QTMP is a promising anticancer therapeutic agent for patients with CRC, including those cancer cells with P-gp-mediated MDR. The present study also indicates that the design and synthesis of anticancer drugs based on thiourea polymers is promising and valuable, thereby offering a new strategy to address MDR, and provides reference resources for further investigations of thiourea polymers.

Antifungal activity of peptide MSI-1 against Cryptococcus neoformans infection in vitro and in murine cryptococcal meningoencephalitis.

The development of novel antifungal agents with high efficacy, low drug tolerance and few side effects is urgent. MSI-1 (GIWKFLKKAKKFWK-NH2), a cationic antimicrobial peptide, may be an attractive antifungal agent because of its structural characteristics, perfect stability against pH and high-temperature/salt, low toxicity towards mammalian cells and low potential for emergence of drug tolerance. In this study, the antifungal activity of MSI-1 in vitro and in a murine model of cryptococcal meningoencephalitis was evaluated. Zeta potential assay, flow cytometry, fluorescence microscope, transmission electron microscopy and microscale thermophoresis were performed to clarify the mechanisms underlying MSI-1 against C. neoformans. The results showed that MSI-1 exerted effective anti-cryptococcal activity in vitro, with MICs of 8-16 µg/mL and MFCs of 8-32 µg/mL, and in a C neoformans-infected mouse model, with significantly improved animal survival, decreased production of pro-inflammatory cytokines and alleviated lung injury, because the potent and rapid fungicidal activity of MSI-1 could effectively eliminate fungal counts in mouse organs. We confirmed that the positively charged peptide bound to C. neoformans by electrostatic attraction after interacting with glucuronoxylomannan (the primary component of C. neoformans capsule). Subsequently, MSI-1 increased the membrane fluidity of fungal cells and the cell membrane permeability, causing destabilized membrane integrity and leading to the final death of fungi. Collectively, MSI-1 possessed potent anti-cryptococcal activity via its notable membrane disruption effect and may be a potential candidate for use in antifungal infection induced by C. neoformans, especially azole-resistant cryptococcus.

Characterization of a polysaccharide from Eupolyphaga sinensis walker and its effective antitumor activity via lymphocyte activation.

A polysaccharide (ESPS) purified from Eupolyphaga sinensis Walker by ion exchange chromatography and gel chromatography was investigated, including its structure characterization and antitumor activity. The results showed that ESPS was composed of rhamnose, fucose, arabinose, xylose, glucose, and galactose in a molar ratio of 7.4: 3.1: 13.9: 9.3: 39.7: 26.5, with the mean weight (Mw) of 2.14 × 104Da; the main chain of ESPS was mainly composed of → 4) - α - D - Glcp - (1 â†’ and → 3) - ß - D - Galp - (1 →, and the side chains were connected to the main chain through the O-6 atom of glucose and O-4 and O-6 atom of galactose. In addition, ESPS promoted the lymphocyte proliferation and inhibited liver cancer cells growth through enhancing lymphocyte activity in vitro, mainly NK cells. Moreover, ESPS markedly stimulated immunity in H22-bearing mice by increasing the spleen and thymus indices and effectively inhibited H22 cell growth in vivo. These data indicated that ESPS was a polysaccharide component possessing high anti-hepatocellular carcinoma activity, representing a potential immunotherapy candidate for the treatment of liver cancer.

5-(3,4,5-trimethoxybenzoyl)-4-methyl-2-(p-tolyl) imidazol (BZML) targets tubulin and DNA to induce anticancer activity and overcome multidrug resistance in colorectal cancer cells.

Colorectal cancer (CRC) is one of the most common malignancies, and multidrug resistance (MDR) reduces the efficiency of anticancer drugs. Therefore, the development of novel anticancer drugs that are highly active against CRC with MDR is urgently needed. Our previous study showed that 5-(3,4,5-trimethoxybenzoyl)-4-methyl-2-(p-tolyl) imidazol (BZML) is not a P-glycoprotein (P-gp) substrate and has a potent anticancer effect against paclitaxel -sensitive or -resistant non-small-cell lung cancer (NSCLC) in vitro and in vivo. In the present study, we found that BZML exhibited strong anticancer activity not only in sensitive CRC cells (SW480 and HCT-116 cells) but also in intrinsically drug-resistant CRC cells (Caco2 cells). In addition, by targeting the colchicine binding site, BZML inhibited tubulin polymerization, which induced G2/M phase arrest, and it caused DNA damage by directly targeting DNA or producing ROS. Further, BZML induced apoptosis through the time-dependent ROS-mediated mitochondrial apoptotic pathway in the CRC cells. Additionally, BZML inhibited P-gp-mediated drug efflux and enhanced the inhibition of the cell growth that had been induced by paclitaxel or doxorubicin in Caco2 cells. In summary, BZML is a multi-targeted anticancer drug that targets tubulin and DNA, and the mechanisms underlying its potent anticancer activity involve disrupting microtubule assembly, causing DNA damage, inducing cell cycle arrest and eventually activating the ROS-mediated mitochondrial apoptotic pathway in SW480, HCT-116 and Caco2 cells. Therefore, the novel compound BZML is a promising anticancer drug that has tremendous potential for CRC treatment, especially for the treatment of drug-resistant CRC.

Polysaccharide enhanced NK cell cytotoxicity against pancreatic cancer via TLR4/MAPKs/NF-κB pathway in vitro/vivo.

A polysaccharide isolated from Strongylocentrotus nudus eggs (SEP) reportedly displays immune activity in vivo. Here, its effect and underlying mechanism in the treatment of pancreatic cancer were investigated. SEP obviously inhibited pancreatic cancer growth by activating NK cells in vitro/vivo via TLR4/MAPKs/NF-κB signaling pathway, The tumor inhibitory rate achieved to 44.5% and 50.8% at a dose of 40 mg/kg in Bxpc-3 and SW1990 nude mice, respectively. Moreover, SEP obviously augmented the Gemcitabine (GEM) antitumor effect by upregulating NKG2D, which improved the sensitivity of NK cells targeting to its ligand MICA; meanwhile, the antitumor inhibitory rate was 68.6% in BxPC-3 tumor-bearing mice. Moreover, SEP reversed GEM-induced apoptosis and atrophy in both spleen and bone marrow via suppressing ROS secretion in vivo. These results suggested that pancreatic cancer was effectively inhibited by SEP-enhanced NK cytotoxicity mediated primarily through TLR4/MAPKs/NF-κB signaling pathway, representing a potential immunotherapy candidate for the treatment of pancreatic cancer.

Decrease of AIM2 mediated by luteolin contributes to non-small cell lung cancer treatment.

Non-small cell lung cancer (NSCLC) is one of the most common malignancies in the world. Although extensive studies showed that luteolin exhibited antitumor effects against NSCLC, the mechanism has not been fully established. In the present study, we found that luteolin significantly reduced the expression of absent in melanoma 2 (AIM2) at both mRNA and protein levels leading to the suppression of AIM2 inflammasome activation, which induced G2/M phase arrest and inhibited epithelial-mesenchymal transition (EMT) in NSCLC. Furthermore, the inhibitory effects of luteolin on NSCLC cells were abolished by the knockdown of AIM2. On the contrary, the antitumor effects of luteolin could be notably reversed by the overexpression of AIM2. In addition, luteolin reduced poly(dA:dT)-induced caspase-1 activation and IL-1ß cleavage in NSCLC cells. These findings suggested that AIM2 was essential to luteolin-mediated antitumor effects. The antitumor effects of luteolin, which were closely associated with AIM2, were also confirmed in the A549 and H460 xenograft mouse models. Collectively, our study displayed that the antitumor effects of luteolin on NSCLC were AIM2 dependent and the downregulation of AIM2 might be an effective way for NSCLC treatment.

Inhibition of peptide BF-30 on influenza A virus infection in vitro/vivo by causing virion membrane fusion.

Influenza A virus is a leading cause of mortality in humans and poses a global health emergency due to its newly adapted and resistant strains. Thus, there is an urgency to develop novel anti-influenza drugs. Peptides are a type of biological molecule having a wide range of inhibitory effects against bacteria, fungi, viruses and cancer cells. The prospects of several peptides and their mechanisms of action have received significant attention. BF-30, a 30 amino acid residue peptide isolated from the venom of the snake, Bungarus fasciatus, is reported to have antibacterial and antitumor activities. Here, we demonstrated that the 50% cytotoxic concentration (CC50) of the peptide to MDCK cells is 67.7 µM. While BF-30 could inhibit the influenza virus strains H1N1, H3N2 and the oseltamivir-resistant strain H1N1, in vitro, with 50% effective concentration (EC50) of 5.2, 7.4 and 18.9 µM, respectively. In animal experiments, mice treated with BF-30 showed 50% survival at a dosage of 4 µM, with an approximately 2 log viral titer decrease in the lung. However, further studies showed that BF-30 worked on only the virus invasion stage, and inhibited the influenza virus infection by causing virion membrane fusion rather than interacting with hemagglutinin or neuraminidase. These results demonstrated that the peptide BF-30 exhibited an effective inhibitory activity against the influenza A virus and could be a promising candidate for influenza virus therapy.