Nanoparticle-enhanced postbiotics: Revolutionizing cancer therapy through effective delivery.

AIM: Gastric cancer contributes to cancer-related fatalities. Conventional chemotherapy faces challenges due to severe adverse effects, prompting recent research to focus on postbiotics, which are safer biomolecules derived from nonviable probiotics. Despite promising in vitro results, efficient in vivo delivery systems remain a challenge. This study aimed to design a potential nanoparticle (NP) formulation encapsulating the Lacticaseibacillus paracasei GMNL-133 (SGMNL-133) isolate to enhance its therapeutic efficacy in treating gastric cancer. MAIN METHODS: We successfully isolated GMNL-133 (SGMNL-133) by optimizing the lysate extraction and column elution processes for L. paracasei GMNL-133, resulting in substantial enhancement of its capacity to inhibit the proliferation of gastric cancer cells. Additionally, we developed a potential NP utilizing arginine-chitosan and fucoidan encapsulating SGMNL-133. KEY FINDINGS: This innovative approach protected the SGMNL-133 from degradation by gastric acid, facilitated its penetration through the mucus layer, and enabled interaction with gastric cancer cells. Furthermore, in vivo experiments demonstrated that the encapsulation of SGMNL-133 in NPs significantly enhanced its efficacy in the treatment of orthotopic gastric tumors while simultaneously reducing tissue inflammation levels. SIGNIFICANCE: Recent research highlights postbiotics as a safe alternative, but in vivo delivery remains a challenge. Our study optimized the extraction of the lysate and column elution of GMNL-133, yielding SGMNL-133. We also developed NPs to protect SGMNL-133 from gastric acid, enhance mucus penetration, and improve the interaction with gastric cancer cells. This combination significantly enhanced drug delivery and anti-gastric tumor activity.

Regulatory effects of Lactobacillus plantarum-GMNL6 on human skin health by improving skin microbiome.

Bacteria response to their environment by producing some compounds which are used in cosmetic and pharmaceutical applications. Some probiotics can regulate immune response and modulate the symptoms of several diseases. Bacteria affect skin response to skin care products. Bacteria are thought to play an important role in acne incidence, skin moisture, and nutrient metabolism, but only a few studies have focused on the extracts of Lactobacillus plantarum in skin care. In this study, we identified that L. plantarum-GMNL6 enhanced collagen synthesis and the gene expression of serine palmitoyltransferase small subunit A. Meanwhile, L. plantarum-GMNL6 reduced the melanin synthesis, the biofilm of Staphylococcus aureus, and the proliferation of Cutibacterium acnes. Information from clinical observation during the ointment for external face use in people displayed that the syndromes of skin moisture, skin color, spots, wrinkles, UV spots, and porphyrins were improved. The diversification of human skin microbiomes was affected by smearing the face of volunteers with L. plantarum-GMNL6. Understanding the potential mechanisms of the action of L. plantarum-GMNL6 in dermatologic conditions promotes the development of care products.

Discoidin Domain Receptor-1 (DDR1) is Involved in Angiolymphatic Invasion in Oral Cancer.

The discoidin domain receptor-1 (DDR1) is a non-integrin collagen receptor recently implicated in the collective cell migration of other cancer types. Previously, we identified an elevated expression of DDR1 in oral squamous cell carcinoma (OSCC) cells. Through the data mining of a microarray dataset composed of matched tumor-normal tissues from forty OSCC patients, we distilled overexpressed genes statistically associated with angiolymphatic invasion, including DDR1, COL4A5, COL4A6 and PDPN. Dual immunohistochemical staining further confirmed the spatial locations of DDR1 and PDPN in OSCC tissues indicative of collective cancer cell invasion. An elevated DDR1 expression at both the transcription and protein level was observed by treating keratinocytes with collagen of fibrillar or basement membrane types. In addition, inhibition of DDR1 kinase activity in OSCC TW2.6 cells disrupted cell cohesiveness in a 2D culture, reduced spheroid invasion in a collagen gel matrix, and suppressed angiolymphatic invasion in xenograft tissues. Taken together, these results suggest that collagen deposition in the affected tissues followed by DDR1 overexpression could be central to OSCC tumor growth and angiolymphatic invasion. Thus, DDR1 inhibitors are potential therapeutic compounds in restraining oral cancer, which has not been previously explored.

Lactobacillus pentosus GMNL-77 inhibits skin lesions in imiquimod-induced psoriasis-like mice.

Psoriasis, which is regarded as a T-cell-mediated chronic inflammatory skin disease, is characterized by hyperproliferation and poor differentiation of epidermal keratinocytes. In this study, we aimed to determine the in vivo effect of a potentially probiotic strain, Lactobacillus pentosus GMNL-77, in imiquimod-induced epidermal hyperplasia and psoriasis-like skin inflammation in BALB/c mice. Oral administration of L. pentosus GMNL-77 significantly decreased erythematous scaling lesions. Real-time polymerase chain reaction showed that treatment with L. pentosus GMNL-77 significantly decreased the mRNA levels of proinflammatory cytokines, including tumor necrosis factor-alpha, interleukin (IL)-6, and the IL-23/IL-17A axis-associated cytokines (IL-23, IL-17A/F, and IL-22) in the skin of imiquimod-treated mice. In addition, we found that L. pentosus GMNL-77 decreased the spleen weights of the imiquimod-treated group and reduced the numbers of IL-17- and IL-22-producing CD4+ T cells in the spleen. In conclusion, the present study provides insight into the potential use of L. pentosus GMNL-77 in the future treatment of psoriasis.

Inhibition of Epstein-Barr virus reactivation in nasopharyngeal carcinoma cells by dietary sulforaphane.

Epstein-Barr virus (EBV) has been associated with several human malignancies including nasopharyngeal carcinoma (NPC). Reactivation of latent EBV has been considered to contribute to the carcinogenesis of NPC. Blocking the EBV lytic cycle has been shown effective in the treatment of EBV-associated diseases. We have searched for natural dietary compounds inhibiting EBV reactivation in NPC cells. Among them, sulforaphane (SFN) was found to be effective in the inhibition of EBV reactivation in latent EBV-positive NPC cells, NA and HA. SFN is a histone deacetylase (HDAC) inhibitor and has been recognized as an antioxidant and antitumor compound for chemoprevention. However, its antiviral effect is less well elucidated. In this study, after determination of the cytotoxicity of SFN on various epithelial cells, we showed that SFN treatment inhibits EBV reactivation, rather than induction, by detection of EBV lytic gene expression in EBV-positive NPC cells. We also determined that the number of cells supporting the EBV lytic cycle is decreased using immunofluorescence and flow cytometric analysis. Moreover, we have found that this inhibitory effect decreases virus production. To elucidate the inhibitory mechanism of SFN on the EBV lytic cycle, luciferase reporter assays were carried out on the Zta and Rta promoters. The results show that SFN inhibits transactivation activity of the EBV immediate-early gene Rta but not Zta. Together, our results suggest that SFN has the capability to inhibit EBV lytic cycle and the potential to be taken as a dietary compound for prevention of EBV reactivation.

Suppressive regulation of KSHV RTA with O-GlcNAcylation.

BACKGROUND: The replication and transcription activator (RTA) of Kaposi's sarcoma-associated herpesvirus (KSHV) is a molecular switch that initiates a productive replication of latent KSHV genomes. KSHV RTA (K-RTA) is composed of 691 amino acids with high Ser and Thr content (17.7%), but to what extent these Ser and Thr are modified in vivo has not been explored. METHODS: By using tandem mass spectrometric analysis of affinity-purified FLAG tagged K-RTA, we sought to identify Ser and Thr residues that are post-translationally modified in K-RTA. RESULTS: We found that K-RTA is an O-GlcNAcylated protein and Thr-366/Thr-367 is the primary motif with O-GlcNAcylation in vivo. The biological significance of O-GlcNAc modified Thr-366 and Thr-367 was assessed by site-specific amino acid substitution. Replacement of Thr with Ala at amino acid 366 or 367 caused a modest enhancement of K-RTA transactivation activity in a luciferase reporter assay and a cell model for KSHV reactivation. By using co-immunoprecipitation coupled with western blot analysis, we showed that the capacity of K-RTA in associating with endogenous PARP1 was significantly reduced in the Thr-366/Thr-367 O-GlcNAc mutants. PARP1 is a documented negative regulator of K-RTA that can be ascribed by the attachment of large negatively charged polymer onto K-RTA via PARP1's poly (ADP-ribose) polymerase activity. In agreement, shRNA-mediated depletion of O-GlcNAc transferase (OGT) in KSHV infected cells augmented viral reactivation and virus production that was accompanied by diminished K-RTA and PARP1 complexes. CONCLUSIONS: KSHV latent-lytic switch K-RTA is modified by cellular O-GlcNAcylation, which imposes a negative effect on K-RTA transactivation activity. This inhibitory effect involves OGT and PARP1, two nutritional sensors recently emerging as chromatin modifiers. Thus, we speculate that the activity of K-RTA on its target genes is continuously checked and modulated by OGT and PARP1 in response to cellular metabolic state.

Ser-634 and Ser-636 of Kaposi's Sarcoma-Associated Herpesvirus RTA are Involved in Transactivation and are Potential Cdk9 Phosphorylation Sites.

The replication and transcription activator (RTA) of Kaposi's sarcoma-associated herpesvirus (KSHV), K-RTA, is a lytic switch protein that moderates the reactivation process of KSHV latency. By mass spectrometric analysis of affinity purified K-RTA, we showed that Thr-513 or Thr-514 was the primary in vivo phosphorylation site. Thr-513 and Thr-514 are proximal to the nuclear localization signal ((527)KKRK(530)) and were previously hypothesized to be target sites of Ser/Thr kinase hKFC. However, substitutions of Thr with Ala at 513 and 514 had no effect on K-RTA subcellular localization or transactivation activity. By contrast, replacement of Ser with Ala at Ser-634 and Ser-636 located in a Ser/Pro-rich region of K-RTA, designated as S634A/S636A, produced a polypeptide with ∼10 kDa shorter in molecular weight and reduced transactivation in a luciferase reporter assay relative to the wild type. In contrast to prediction, the decrease in molecular weight was not due to lack of phosphorylation because the overall Ser and Thr phosphorylation state in K-RTA and S634A/S636A were similar, excluding that Ser-634 or Ser-636 motif served as docking sites for consecutive phosphorylation. Interestingly, S634A/S636A lost ∼30% immuno-reactivity to MPM2, an antibody specific to pSer/pThr-Pro motif, indicating that (634)SPSP(637) motif was in vivo phosphorylated. By in vitro kinase assay, we showed that K-RTA is a substrate of CDK9, a Pro-directed Ser/Thr kinase central to transcriptional regulation. Importantly, the capability of K-RTA in associating with endogenous CDK9 was reduced in S634A/S636A, which suggested that Ser-634 and Ser-636 may be involved in CDK9 recruitment. In agreement, S634A/S636A mutant exhibited ∼25% reduction in KSHV lytic cycle reactivation relative to that by the wild type K-RTA. Taken together, our data propose that Ser-634 and Ser-636 of K-RTA are phosphorylated by host transcriptional kinase CDK9 and such a process contributes to a full transcriptional potency of K-RTA.

Epstein-Barr virus (EBV) Rta-mediated EBV and Kaposi's sarcoma-associated herpesvirus lytic reactivations in 293 cells.

Epstein-Barr virus (EBV) Rta belongs to a lytic switch gene family that is evolutionarily conserved in all gamma-herpesviruses. Emerging evidence indicates that cell cycle arrest is a common means by which herpesviral immediate-early protein hijacks the host cell to advance the virus's lytic cycle progression. To examine the role of Rta in cell cycle regulation, we recently established a doxycycline (Dox)-inducible Rta system in 293 cells. In this cell background, inducible Rta modulated the levels of signature G1 arrest proteins, followed by induction of the cellular senescence marker, SA-ß-Gal. To delineate the relationship between Rta-induced cell growth arrest and EBV reactivation, recombinant viral genomes were transferred into Rta-inducible 293 cells. Somewhat unexpectedly, we found that Dox-inducible Rta reactivated both EBV and Kaposi's sarcoma-associated herpesvirus (KSHV), to similar efficacy. As a consequence, the Rta-mediated EBV and KSHV lytic replication systems, designated as EREV8 and ERKV, respectively, were homogenous, robust, and concurrent with cell death likely due to permissive lytic replication. In addition, the expression kinetics of EBV lytic genes in Dox-treated EREV8 cells was similar to that of their KSHV counterparts in Dox-induced ERKV cells, suggesting that a common pathway is used to disrupt viral latency in both cell systems. When the time course was compared, cell cycle arrest was achieved between 6 and 48 h, EBV or KSHV reactivation was initiated abruptly at 48 h, and the cellular senescence marker was not detected until 120 h after Dox treatment. These results lead us to hypothesize that in 293 cells, Rta-induced G1 cell cycle arrest could provide (1) an ideal environment for virus reactivation if EBV or KSHV coexists and (2) a preparatory milieu for cell senescence if no viral genome is available. The latter is hypothetical in a transient-lytic situation.

Procaspase 8 and Bax are up-regulated by distinct pathways in Streptococcal pyrogenic exotoxin B-induced apoptosis.

We have previously identified integrin alpha(v)beta(3) and Fas as receptors for the streptococcal pyrogenic exotoxin B (SPE B), and G308S, a mutant of SPE B that binds to Fas only. In the current study we found that after binding to alpha(v)beta(3), SPE B stimulated the tyrosine phosphorylation of JAK2 and STAT1. STAT1 tyrosine phosphorylation was inhibited by a JAK2 inhibitor, AG490, short interfering RNA (siRNA) silencing of JAK2, and anti-alpha(V)beta(3) antibody. AG490 also decreased the binding of tyrosine-phosphorylated STAT1 to the procaspase 8 promoter, decreasing procaspase 8 expression, suggesting that SPE B up-regulates procaspase 8 expression via the JAK2/STAT1 pathway. Alternatively, both SPE B and G308S increased STAT1 phosphorylation at serine 727, which was inhibited by anti-Fas antibody, a p38 inhibitor, SB203580, and siRNA silencing of p38. In addition, SPE B and G308S increased binding of serine-phosphorylated STAT1 to the Bax promoter and Bax expression, which was decreased by SB203580. SPE B and G308S-stimulated Bax expression was also inhibited by anti-Fas antibody. These findings suggest that Fas mediate SPE B-induced Bax expression through p38. Silencing of JAK2 or p38 by siRNA blocked procaspase 8 expression, whereas only p38 siRNA decreased Bax expression. Furthermore, JAK2 inhibition and p38 inhibition reduced SPE B-induced apoptosis, but only p38 inhibition blocked G308S-induced apoptosis.

The Epstein-Barr virus replication and transcription activator, Rta/BRLF1, induces cellular senescence in epithelial cells.

Epstein-Barr Virus (EBV) replication and transcription activator (Rta/BRLF1) is an immediate-early transcription factor that controls the conversion of the latent viral genome into one undergoing lytic replication. By using a doxycycline-inducible expression system, the present study demonstrates that EBV Rta efficiently elicits growth arrest in the human epithelial cell line HEK293. In cells arrested by EBV Rta, the expression of p21 (CDKN1A), p27 (CDKN1B) and cyclin E were increased. In contrast, the levels of cyclin D1, CDK4 and CDK6 were sharply decreased. Activation of the host cell DNA damage response (DDR), indicated by the increasing phosphorylation of H2AX and p53 Ser15, was observed on day 3 and day 5 after EBV Rta expression, respectively. Finally, EBV Rta arrested cells exhibited strong senescence-associated beta-galactosidase staining on day 10 after doxycycline induction. Together, these results indicate that, in addition to triggering viral lytic replication in epithelial cells, EBV Rta concurrently initiates a cellular senescence program that was previously undocumented. This finding, showing Rta may be centrally involved in inducing a host cell state amenable to efficient viral reproduction, in addition to its previously characterized regulation of viral transcription, provides new perspectives in understanding EBV pathogenesis.

Streptococcal pyrogenic exotoxin B-induced apoptosis in A549 cells is mediated through alpha(v)beta(3) integrin and Fas.

Our previous work suggested that streptococcal pyrogenic exotoxin (SPE) B-induced apoptosis is mediated through a receptor-like mechanism. In this study, we have identified alpha(v)beta(3) and Fas as the SPE B receptors for this function. The SPE B fragment without the RGD motif and G308S, a SPE B mutant with the RSD motif, induced less apoptosis than did native SPE B, suggesting that the RGD motif is critical for SPE B-induced apoptosis. Fluorescein isothiocyanate-SPE B binding assays and immunoprecipitation analysis showed that SPE B specifically interacted with alpha(v)beta(3). Anti-alpha(v)beta(3) antibody partially inhibited SPE B-induced apoptosis but had no effect on G308S-induced apoptosis. In addition, Fas binding to SPE B was verified in an affinity column and an immunoprecipitation analysis. Anti-Fas antibody inhibited SPE B- and G308S-induced apoptosis in a dose-dependent manner, suggesting that Fas-mediated SPE B-induced apoptosis also occurs RGD independently. Both anti-alpha(v)beta(3) and anti-Fas antibodies synergistically inhibited SPE B-induced apoptosis. The apoptotic cascades were activated by SPE B and G308S, with a little delay by the latter. After SPE B binding, the cell surface level of alpha(v)beta(3), but not of Fas, was decreased. The decreased alpha(v)beta(3) level was restored by treatment with the proteasome inhibitor MG132, suggesting a SPE B-mediated endocytosis of integrin alpha(v)beta(3) via the ubiquitin-proteasome system. Taken together, our results demonstrate that SPE B-induced apoptosis is mediated through alpha(v)beta(3) integrin and Fas in a synergistic manner.

The induction and possible subsequent effect of human antibodies against porcine enamel matrix derivative.

BACKGROUND: The amino acid sequence of porcine amelogenin, the major component of enamel matrix derivative (EMD), is approximately 91% identical to that of its human counterpart. Whether porcine EMD (pEMD) can elicit neutralizing antibodies after the first surgery, thereby reducing the clinical effect of secondary surgery, has not been established. METHODS: The sera of patients receiving periodontal surgery with or without pEMD were collected before and after surgery. The pEMD product was subjected to electrophoresis and transferred for a Western blot using the purified antibodies from patients as the primary antibodies. To clarify whether the antibodies in patients could inhibit the production of transforming growth factor-beta1 (TGF-beta1), we added different amounts of purified antibodies from pEMD patients (before versus after surgery) into the cell cultures of periodontal ligament fibroblasts. The conditioned media were then collected for an immunoassay of TGF-beta1. RESULTS: The result of the Western blot demonstrated that human antibodies against pEMD were elicited 10 days after surgery. Using mass spectrometry, a non-specific band on the Western blot appeared to be porcine immunoglobulin G (IgG). The results of the immunoassay showed the antibodies from pEMD-treated patients did not hinder the subsequent production of TGF-beta1. CONCLUSIONS: The pEMD product was contaminated with porcine IgG. The application of the product could induce antibodies against different isoforms of porcine amelogenin in humans. However, the increased antibodies did not hinder the production of TGF-beta1, one of the established in vitro functions of pEMD on periodontal ligament fibroblasts.

Streptococcal pyrogenic exotoxin B cleaves properdin and inhibits complement-mediated opsonophagocytosis.

Streptococcal pyrogenic exotoxin B (SPE B), a cysteine protease, is an important virulence factor in group A streptococcal (GAS) infection. The reduction of phagocytic activity by SPE B may help prevent bacteria from being ingested. In this study, we investigated the mechanism SPE B uses to enable bacteria to resist opsonophagocytosis. Using Western blotting and an affinity column immobilized with SPE B, we found that both SPE B and C192S, an SPE B mutant lacking protease activity, bound to serum properdin, and that SPE B, but not C192S, degraded serum properdin. Further study showed that SPE B-treated, but not C192S-treated, serum blocked the alternative complement pathway. Reconstitution of properdin into SPE B-treated serum unblocked the alternative pathway. GAS opsonized with SPE B-treated serum was more resistant to neutrophil killing than GAS opsonized with C192S-treated or normal serum. These results suggest that a novel SPE B mechanism, one which degrades serum properdin, enables GAS to resist opsonophagocytosis.

Streptococcal pyrogenic exotoxin B-induced apoptosis in a549 cells is mediated by a receptor- and mitochondrion-dependent pathway.

It has been shown that streptococcal pyrogenic exotoxin B (SPE B) can induce cells to undergo apoptosis. The present study is to dissect the role of SPE B protease and SPE B protein in the apoptotic process of A549 cells and to elucidate the SPE B-induced apoptotic pathway. Recombinant SPE B (rSPE B) and C192S, a mutant of SPE B without protease activity, were expressed in Escherichia coli and purified by using an affinity column. The apoptosis of A549 cells was assayed by propidium iodide staining, followed by flow cytometry analysis. Our results showed that SPE B induced apoptosis in a dose-dependent manner, whereas C192S did not. When cells were pretreated with rSPE B (2 mug/ml) for as briefly as 5 min and then incubated with C192S of 28 kDa, an apoptosis that is proportional to the period of pretreatment was observed but not with C192S of 42 kDa. These results suggest that the extracellular protease activity of rSPE B is required for the initiation of apoptosis and that the size of SPE B is important for an effective induction of apoptosis. The time course analysis revealed that molecules activated in apoptosis were in the following order: caspase-8 (1.5 h), t-Bid (2.5 h), Bax (3 h), cytochrome c release (6 h), caspase-9 (7 h), and caspase-3 (8 h). The overexpression of Bcl-2 inhibited depolarization of mitochondrial membrane, cytochrome c release, and apoptosis. The results of the present study suggest that SPE B-induced apoptosis is mediated through a receptor-like mechanism and a mitochondrion-dependent pathway.

Syndecan-1 up-regulated by ephrinB2/EphB4 plays dual roles in inflammatory angiogenesis.

EphrinB2 and EphB4, its cognate receptor, are important in the vascular development of the mouse embryo. Their roles in human inflammatory angiogenesis, however, are not well understood. By examining hyperinflammatory lesions, we saw that ephrinB2 was predominantly expressed in macrophage-like cells and EphB4 in small venules. Because macrophages usually transmigrate through postcapillary venules during inflammation, we wanted to explore the downstream effects of EphB4 after binding to ephrinB2. By using cDNA microarray technique and following reverse transcriptase-polymerase chain reaction (RT-PCR), we found that syntenin and syndecan-1 were up-regulated in EphB4-positive endothelial cells dose dependently and time dependently after stimulation with preclustered ephrinB2. In vitro, ephrinB2 suppressed the angiogenic effects of basic fibroblast growth factor (bFGF) on EphB4-positive endothelial cells, partially due to syndecan-1's competition with fibroblast growth factor receptor (FGFR) for bFGF. However, ephrinB2 exhibited angiogenic effects in vivo, possibly due to an inflammation-associated enzyme-heparanase. The enzymes could convert the inhibitory effect of ephrinB2 on EphB4-positive endothelial cells to an activating effect by removing poorly sulfated side chains of up-regulated syndecan-1 ectodomain. Depending on the presence of heparanases, the roles of syndecan-1 may be opposite in different physiological settings.