Multivalent Carbohydrate Nanocomposites for Tumor Microenvironment Remodeling to Enhance Antitumor Immunity

Current cancer immunotherapeutic strategies mainly focus on remodeling the tumor microenvironment (TME) to make it favorable for antitumor immunity. Increasing attention has been paid to developing innovative immunomodulatory adjuvants that can restore weakened antitumor immunity by conferring immunogenicity to inflamed tumor tissues. Here, a galactan-enriched nanocomposite (Gal-NC) is developed from native carbohydrate structures through an optimized enzymatic transformation for effective, stable, and biosafe innate immunomodulation. Gal-NC is characterized as a carbohydrate nanoadjuvant with a macrophage-targeting feature. It is composed of repeating galactan glycopatterns derived from heteropolysaccharide structures of plant origin. The galactan repeats of Gal-NC function as multivalent pattern-recognition sites for Toll-like receptor 4 (TLR4). Functionally, Gal-NC-mediated TLR activation induces the repolarization of tumor-associated macrophages (TAMs) toward immunostimulatory/tumoricidal M1-like phenotypes. Gal-NC increases the intratumoral population of cytotoxic T cells, the main effector cells of antitumor immunity, via re-educated TAMs. These TME alterations synergistically enhance the T-cell-mediated antitumor response induced by αPD-1 administration, suggesting that Gal-NC has potential value as an adjuvant for immune checkpoint blockade combination therapies. Thus, the Gal-NC model established herein suggests a glycoengineering strategy to design a carbohydrate-based nanocomposite for advanced cancer immunotherapies.

NAMPT mitigates colitis severity by supporting redox-sensitive activation of phagocytosis in inflammatory macrophages

Nicotinamide phosphoribosyltransferase (NAMPT) is the rate-limiting enzyme in the nicotinamide adenine dinucleotide (NAD+) salvage pathway and plays a crucial role in the maintenance of the NAD+ pool during inflammation. Considering that macrophages are essential for tissue homeostasis and inflammation, we sought to examine the functional impact of NAMPT in inflammatory macrophages, particularly in the context of inflammatory bowel disease (IBD). In this study, we show that mice with NAMPT deletion within the myeloid compartment (Namptf/fLysMCre+/-, Nampt mKO) have more pronounced colitis with lower survival rates, as well as numerous uncleared apoptotic corpses within the mucosal layer. Nampt-deficient macrophages exhibit reduced phagocytic activity due to insufficient NAD+ abundance, which is required to produce NADPH for the oxidative burst. Nicotinamide mononucleotide (NMN) treatment rescues NADPH levels in Nampt mKO macrophages and sustains superoxide generation via NADPH oxidase. Consequently, Nampt mKO mice fail to clear dead cells during tissue repair, leading to substantially prolonged chronic colitis. Moreover, systemic administration of NMN, to supply NAD+, effectively suppresses the disease severity of DSS-induced colitis. Collectively, our findings suggest that activation of the NAMPT-dependent NAD+ biosynthetic pathway, via NMN administration, is a potential therapeutic strategy for managing inflammatory diseases.

Low-level expression of necroptosis factors indicates a poor prognosis of the squamous cell carcinoma subtype of non-small-cell lung cancer

Background

The programmed cell death pathway necroptosis may synergize with the DNA damage response (DDR) in opposing tumor progression. While our basic mechanistic understanding of the necroptotic cell death advances rapidly, its prognostic implications have not been thoroughly examined in cancers.

Methods

We included 394 patients with stage I non-small-cell lung cancer (NSCLC) who underwent surgical tumor resection between 1 January 1997 and 31 December 2011 and measured expression levels of nine proteins involved in necroptosis and the DDR in primary samples from 394 patients using tissue microarray. Protein expression evaluated by using an H-score method was dichotomized by the median value. The overall survival as the endpoint was calculated from the time of diagnosis to the time of the last follow-up or death.

Results

We find that low-level expression of the necroptosis markers RIPK3 and PELI1 is associated with high risk of patient death. High-level expression of the key DDR factor p53 in combination with low-level expression of either RIPK3 or PELI1 increases the risk further. These gene expression effects appear to occur specifically in the squamous cell carcinoma (SCC) subtype of stage I NSCLC, while not observed in the non-SCC subtypes.

Conclusions

Low-level expression of such necroptosis factors as RIPK3 and PELI1 in combination with high-level expression of the DDR factor p53 can serve as a critical indicator in predicting survival of stage I NSCLC patients with the SCC subtype.

TRIM24-RIP3 axis perturbation accelerates osteoarthritis pathogenesis

OBJECTIVES

Recently, necroptosis has attracted increasing attention in arthritis research; however, it remains unclear whether its regulation is involved in osteoarthritis (OA) pathogenesis. Since receptor-interacting protein kinase-3 (RIP3) plays a pivotal role in necroptosis and its dysregulation is involved in various pathological processes, we investigated the role of the RIP3 axis in OA pathogenesis.

METHODS

Experimental OA was induced in wild-type or Rip3 knockout mice by surgery to destabilise the medial meniscus (DMM) or the intra-articular injection of adenovirus carrying a target gene (Ad-Rip3 and Ad-Trim24 shRNA). RIP3 expression was examined in OA cartilage from human patients; Trim24, a negative regulator of RIP3, was identified by microarray and in silico analysis. Connectivity map (CMap) and in silico binding approaches were used to identify RIP3 inhibitors and to examine their direct regulation of RIP3 activation in OA pathogenesis.

RESULTS

RIP3 expression was markedly higher in damaged cartilage from patients with OA than in undamaged cartilage. In the mouse model, adenoviral RIP3 overexpression accelerated cartilage disruption, whereas Rip3 depletion reduced DMM-induced OA pathogenesis. Additionally, TRIM24 knockdown upregulated RIP3 expression; its downregulation promoted OA pathogenesis in knee joint tissues. The CMap approach and in silico binding assay identified AZ-628 as a potent RIP3 inhibitor and demonstrated that it abolished RIP3-mediated OA pathogenesis by inhibiting RIP3 kinase activity.

CONCLUSIONS

TRIM24-RIP3 axis perturbation promotes OA chronicity by activating RIP3 kinase, suggesting that the therapeutic manipulation of this pathway could provide new avenues for treating OA.

A formulated red ginseng extract inhibits autophagic flux and sensitizes to doxorubicin-induced cell death

Background

Ginseng is believed to have antitumor activity. Autophagy is largely a prosurvival cellular process that is activated in response to cellular stressors, including cytotoxic chemotherapy; therefore, agents that inhibit autophagy can be used as chemosensitizers in cancer treatment. We examined the ability of Korean Red Ginseng extract (RGE) to prevent autophagic flux and to make hepatocellular carcinoma (HCC) cells become more sensitive to doxorubicin.

Methods

The cytotoxic effects of total RGE or its saponin fraction (RGS) on HCC cells were examined by the lactate dehydrogenase assay in a dose- or time-dependent manner. The effect of RGE or RGS on autophagy was measured by analyzing microtubule-associated protein 1A/1B-light chain (LC)3-II expression and LC3 puncta formation in HCC cells. Late-stage autophagy suppression was tested using tandem-labeled green fluorescent protein (GFP)-monomeric red fluorescent protein (mRFP)-LC3.

Results

RGE markedly increased the amount of LC3-II, but green and red puncta in tandem-labeled GFP-mRFP-LC3 remained colocalized over time, indicating that RGE inhibited autophagy at a late stage. Suppression of autophagy through knockdown of key ATG genes increased doxorubicin-induced cell death, suggesting that autophagy induced by doxorubicin has a protective function in HCC. Finally, RGE and RGS markedly sensitized HCC cells, (but not normal liver cells), to doxorubicin-induced cell death.

Conclusion

Our data suggest that inhibition of late-stage autophagic flux by RGE is important for its potentiation of doxorubicin-induced cancer cell death. Therapy combining RGE with doxorubicin could serve as an effective strategy in the treatment of HCC.

Oral immunization with Helicobacter pylori-loaded poly(D, L-lactide-co-glycolide) nanoparticles

BACKGROUND

Helicobacter pylori is a major cause of chronic antral gastritis and peptic ulcer diseases. Many researchers have examined the possibility of immunologically-mediated prevention of H. pylori infection using an oral vaccine. The purpose of this study is to investigate whether mucosal and systemic immune responses are induced by oral immunization with H. pylori lysate-loaded poly(D, L-lactide-coglycolide)[PLG] nanoparticles, and if so, how the distribution of serum IgG subclasses are produced.

METHODS

PLG nanoparticles (H. pylori-PLG) with encapsulated H. pylori lysates were prepared by the solvent evaporation method, and the physical properties of the nanoparticles were investigated. Following the oral immunization of the H. pylori-PLG nanoparticles into mice, antibody induction was assayed in serum and gut washings, and the pattern of serum IgG subclasses was determined by ELISA.

RESULTS

The prepared H. pylori-PLG nanoparticles were spherical, nonporous particles with a mean diameter of less than 1 microm. The multiple oral immunization with H. pylori-PLG nanoparticles induced significantly H. pylori-specific mucosal IgA response as well as serum IgG responses. The serum antibody subclasses elicited were predominantly IgG1 and IgG2b.

CONCLUSION

Our results suggested that oral immunization of H. pylori-PLG nanoparticles induced the H. pylori-specific mucosal and systemic responses in mice and enhanced Th2-type responses.

Induction of mucosal and systemic immune response by oral immunization with H. pylori lysates encapsulated in poly(D,L-lactide-co-glycolide) microparticles

Helicobacter pylori is a major cause of chronic antral gastritis and peptic ulcer diseases. Several kinds of poly(D,L-lactide-coglycolide) microparticles containing H. pylori whole-cell lysate (PLG-HP) were prepared by the solvent evaporation method using double emulsion. Physical properties, such as particle size, protein content, and morphology were investigated. All prepared microparticles showed a smooth surface morphology from 0.5-0.86 microm in diameter and high degree of encapsulation efficiency from 62-75%. SDS-PAGE and immunoblotting of extracted antigen confirmed that the molecular weight and antigenicity of the antigen remained unaltered by the encapsulation procedure. Following the oral immunization of the microparticles to mice, antibody production was assayed in serum and gut washings by ELISA and antibody secreting cells were determined in intestinal lamina propria lymphocytes (LPL) by ELISPOT. Multiple oral immunizations induced significant H. pylori-specific intestinal IgA response as well as serum IgG response than those detected with soluble antigen (P < 0.001). The presence of antibody-secreting cell in intestinal lamina propria lymphocytes (LPL) was correlated with IgA level in gut washing fluids. After boosting at week-8, the antibody induction levels were highly increased irrespective of microparticles prepared with different PLG molecular weights. These data suggested that PLG-HP could stimulate the H. pylori-specific mucosal and systemic response in vivo and might be useful adjuvant in future H. pylori vaccine development.

Synthesis and evaluation of 2 beta-oxyimino and alkenylpenicillanic acid sulfone derivatives as beta-lactamase inhibitors

The synthesis and in vitro synergies of 2 beta-alkenyl and oxyiminopenam sulfone derivatives are described. Most of the compounds synthesized exhibited good inhibitory activities and synergistic antibacterial activities with piperacillin and ceftriaxone, respectively, against several beta-lactamase producing strains. Particularly the 2 beta-alkenylpenam sulfone derivatives. 1e and 1g, showed good synergistic activity with ceftriaxone against Citrobacter freundi NIH 10018-68 and Proteus vulgaris 20. Also the compounds 2a, 2c, and 2f, 2 beta-oxyiminopenam sulfone derivatives, exhibited improved synergistic activity with piperacillin against Citrobacter freundi NIH 10018-68.

Serodiagnosis of Helicobacter pylori infection in Korean patients using enzyme-linked immunosorbent assay

Helicobacter pylori (H. pylori) is a gram-negative spiral bacteria that are associated with gastritis, peptic ulcer and gastric cancer. We have developed enzyme-linked immunosorbent assay (ELISA) that detects serum anti-H. pylori immunoglobulin G antibodies using H. pylori strains isolated from Korean patients. To assess the sensitivity and specificity of our assay system with different commercial kits, serum samples from 249 Korean patients with a variety of gastrointestinal diseases were tested. Among 249 Korean patients, 178 (71.5%) were positive in culture and/or urease test. The sensitivity and specificity between our assay system and four other commercial kits (Bio-Rad, DAKO, ROCHE, and IPR) were as follows: 97.8% and 92%, 94.3% and 53%, 56.5% and 92%, 83.3% and 96%, 58.2% and 92%, respectively. All sera showing discordant immunoassay results between different ELISA kits were confirmed by immunoblot analysis. These results indicate that our assay system showed a highly accurate and reliable results in diagnosis of H. pylori infection in Korean patients.

Identification of immunodominant epitopes in the core and non-structural region of hepatitis C virus by enzyme immunoassay using synthetic peptides

Thirty-two synthetic peptides, components of the core and non-structural protein of Hepatitis C virus (HCV), were tested for their reactivities against antibodies in sera of healthy, HCV antibody positive of chronic liver disease patients. Among them, 8 of the core peptides, 4 of the NS4 peptides and 3 of the NS5 peptides reacted with the HCV infected sera. In particular, C22 (core peptide) and NS4-1924 (NS4 peptide) were most reactive with the serum samples giving a positive signal with commercially available enzyme-linked immunosorbent assay (ELISA) kit. Our results indicate that the immunodominant regions of the HCV-derived proteins are located at three regions in the core protein, three regions in the NS4 protein, and one region in the NS5 protein. These results indicate that the selected peptides are useful antigens in detecting antibodies in the sera from individuals infected with HCV.