Peri-weaning cholera toxin consumption suppresses chemically-induced carcinogenesis in mice.

Gastrointestinal bacteria are known to have an impact on local and systemic immunity, and consequently either promote or suppress cancer development. Following the notion that perinatal bacterial exposure might confer immune system competency for life, we investigated whether early-life administration of cholera-toxin (CT), a protein exotoxin of the small intestine pathogenic bacterium Vibrio cholerae, may shape local and systemic immunity to impart a protective effect against tumor development in epithelia distantly located from the gut. For that, newborn mice were orally treated with low non-pathogenic doses of CT and later challenged with the carcinogen 7,12-dimethylbenzanthracene (DMBA), known to cause mainly mammary, but also skin, lung and stomach cancer. Our results revealed that CT suppressed the overall incidence and multiplicity of tumors, with varying efficiencies among cancer types, and promoted survival. Harvesting mouse tissues at an earlier time-point (105 instead of 294 days), showed that CT does not prevent preneoplastic lesions per se but it rather hinders their evolution into tumors. CT pretreatment universally increased apoptosis in the cancer-prone mammary, lung and nonglandular stomach, and altered the expression of several cancer-related molecules. Moreover, CT had a long-term effect on immune system cells and factors, the most prominent being the systemic neutrophil decrease. Finally, CT treatment significantly affected gut bacterial flora composition, leading among others to a major shift from Clostridia to Bacilli class abundance. Overall, these results support the notion that early-life CT consumption is able to affect host's immune, microbiome and gene expression profiles toward the prevention of cancer.

Differences in the immunoglobulin gene repertoires of IgG versus IgA multiple myeloma allude to distinct immunopathogenetic trajectories.

The analysis of the immunogenetic background of multiple myeloma (MM) has proven key to understanding disease ontogeny. However, limited information is available regarding the immunoglobulin (IG) gene repertoire in MM cases carrying different heavy chain isotypes. Here, we studied the IG gene repertoire in a series of 523 MM patients, of whom 165 and 358 belonged to the IgA and IgG MM groups, respectively. IGHV3 subgroup genes predominated in both groups. However, at the individual gene level, significant (p<0.05) differences were identified regarding IGHV3-21 (frequent in IgG MM) and IGHV5-51 (frequent in IgA MM). Moreover, biased pairings were identified between certain IGHV genes and IGHD genes in IgA versus IgG MM. Turning to the imprints of somatic hypermutation (SHM), the bulk of rearrangements (IgA: 90.9%, IgG: 87.4%) were heavily mutated [exhibiting an IGHV germline identity (GI) <95%]. SHM topology analysis disclosed distinct patterns in IgA MM versus IgG MM cases expressing B cell receptor IG encoded by the same IGHV gene: the most pronounced examples concerned the IGHV3-23, IGHV3-30 and IGHV3-9 genes. Furthermore, differential SHM targeting was also identified between IgA MM versus IgG MM, particularly in cases utilizing certain IGHV genes, alluding to functional selection. Altogether, our detailed immunogenetic evaluation in the largest to-date series of IgA and IgG MM patients reveals certain distinct features in the IGH gene repertoires and SHM. These findings suggest distinct immune trajectories for IgA versus IgG MM, further underlining the role of external drive in the natural history of MM.

Alterations in Faecal Microbiota and Elevated Levels of Intestinal IgA Following Oral Administration of Lacticaseibacillus casei in mice.

The intestinal microbiota has been identified as a crucial regulator of the overall health, with studies describing its influence in a variety of disorders and developmental processes throughout the body. A widely accepted approach of influencing the microbiota and regulating its functionality in health or disease is the consumption of probiotics. In this study, we aimed to identify the impact of probiotic Lacticaseibacillus casei ATCC393 on the intestinal microbiota of mice and circulating soluble products of microbial origin or the immune system. Investigation of the gut microflora using next-generation sequencing analysis revealed alterations in the microbial populations following consumption of the probiotic. Abundance of taxa classified as Muribaculaceae was increased in lactobacilli-fed animals, while abundance of taxa classified as Lachnospiraceae and Oscillospiraceae was decreased. In addition, the composition of the intestinal microbiota was modified by the administration of L. casei, as evident by the clustering of test subjects when inspecting beta diversity, without however any significant effect on the alpha diversity of the animals. Finally, production of IgA in the intestinal lumen of mice that had received the microorganism was significantly increased, as was the concentration of lactic acid, while levels of acetic acid were noticeably lower in the L. casei group. The findings suggest that L. casei can be considered a potential candidate strain for the modulation of intestinal homeostasis and a component of dietary interventions aiming to improve overall health.

Comparative Analysis of SARS-CoV-2 Variants of Concern, Including Omicron, Highlights Their Common and Distinctive Amino Acid Substitution Patterns, Especially at the Spike ORF.

In order to gain a deeper understanding of the recently emerged and highly divergent Omicron variant of concern (VoC), a study of amino acid substitution (AAS) patterns was performed and compared with those of the other four successful variants of concern (Alpha, Beta, Gamma, Delta) and one closely related variant of interest (VoI-Lambda). The Spike ORF consistently emerges as an AAS hotspot in all six lineages, but in Omicron this enrichment is significantly higher. The progenitors of each of these VoC/VoI lineages underwent positive selection in the Spike ORF. However, once they were established, their Spike ORFs have been undergoing purifying selection, despite the application of global vaccination schemes from 2021 onwards. Our analyses reject the hypothesis that the heavily mutated receptor binding domain (RBD) of the Omicron Spike was introduced via recombination from another closely related Sarbecovirus. Thus, successive point mutations appear as the most parsimonious scenario. Intriguingly, in each of the six lineages, we observed a significant number of AAS wherein the new residue is not present at any homologous site among the other known Sarbecoviruses. Such AAS should be further investigated as potential adaptations to the human host. By studying the phylogenetic distribution of AAS shared between the six lineages, we observed that the Omicron (BA.1) lineage had the highest number (8/10) of recurrent mutations.

Lactiplantibacillus plantarum inhibits colon cancer cell proliferation as function of its butyrogenic capability.

Lactobacilli have been shown to inhibit or suppress cancer cell growth through the release of strain-specific bioactive metabolites and their inclusion in functional foods could exert a health promoting activity on human health. Herein, we examined the antiproliferative activity of the Lactiplantibacillus plantarum strains S2T10D and O2T60C, which have been previously shown to exert different butyrogenic activities. Human HT-29 cells were employed as an in vitro colon cancer model and both bacterial strains were found to inhibit their growth. However, the strain S2T10D showed a greater antiproliferative activity which, interestingly, was correlated to its butyrogenic capability. Noteworthy, for the non-butyrogenic strain O2T60C, the growth inhibitory capability was rather limited. Furthermore, both the butyrate-containing supernatant of S2T10D and glucose-deprived cell culture medium supplemented with the same concentration of butyrate found in S2T10D supernatant, induced a pH-independent cancer cell growth inhibition accompanied by downregulation of cyclin D1 at mRNA level. The downregulation of cyclin D1 gene expression was accompanied by cell cycle arrest in G2/M phase and decrease of cyclin B1 and D1 protein levels. This in vitro study underlines the impact of Lpb. plantarum in the growth inhibition of cancer cells, and proposes butyrate-mediated cell cycle regulation as a potential involved mechanism. Since the production of butyric acid in Lpb. plantarum has been proven strain-dependent and differentially boosted by specific prebiotic compounds, our results open future research paths to determine whether this metabolic activity could be modulated in vivo by enhancing this antiproliferative effects on cancer cells.

The Remarkable Evolutionary Plasticity of Coronaviruses by Mutation and Recombination: Insights for the COVID-19 Pandemic and the Future Evolutionary Paths of SARS-CoV-2.

Coronaviruses (CoVs) constitute a large and diverse subfamily of positive-sense single-stranded RNA viruses. They are found in many mammals and birds and have great importance for the health of humans and farm animals. The current SARS-CoV-2 pandemic, as well as many previous epidemics in humans that were of zoonotic origin, highlights the importance of studying the evolution of the entire CoV subfamily in order to understand how novel strains emerge and which molecular processes affect their adaptation, transmissibility, host/tissue tropism, and patho non-homologous genicity. In this review, we focus on studies over the last two years that reveal the impact of point mutations, insertions/deletions, and intratypic/intertypic homologous and non-homologous recombination events on the evolution of CoVs. We discuss whether the next generations of CoV vaccines should be directed against other CoV proteins in addition to or instead of spike. Based on the observed patterns of molecular evolution for the entire subfamily, we discuss five scenarios for the future evolutionary path of SARS-CoV-2 and the COVID-19 pandemic. Finally, within this evolutionary context, we discuss the recently emerged Omicron (B.1.1.529) VoC.

Adenoviral Infections in Bone Marrow Transplanted Adult Patients: A Review of the 44 Cases Reported in the Last 25 Years.

Adenoviral infections in immunocompromised individuals may be life-threatening conditions. The aim of this review is to document all the reported cases of adenoviral infection is patients having undergone bone marrow transplantation (BMT). A comprehensive literature search of the databases Pubmed, Science Direct, and Google Scholar was conducted to identify all the case reports of adenoviral infections in BMT patients. A total of 30 articles with 44 patients were included. The most common underlying condition was acute lymphocytic leukemia (23%) followed by acute myeloid leukemia (18%). The most common site of infection was disseminated (50%), followed by liver infection (8%) and hemorrhagic cystitis (8%). Cidofovir was administered in 40.9% of the cases, and death was reported in 34.4% of them. Ribavirin was administered as monotherapy in 15.9% of patients, with a mortality rate of 57.1%. We found that the antiviral drug option had no statistically significant effect on the mortality rate (p=0.242). Also, the absence of graft-versus-host disease (GVHD) was not associated with an improved outcome (p=0.523). There was, however, a statistically significant difference in the outcome based on the site of infection (p=0.005), with a higher rate of mortality in the disseminated and gastrointestinal cases. To the best of our knowledge, this is the first review documenting all the cases of adenoviral infections in BMT patients. Future randomized studies are needed to validate the results of the present study.

Anticancer Activity of Biogenic Selenium Nanoparticles: Apoptotic and Immunogenic Cell Death Markers in Colon Cancer Cells.

Colorectal cancer is a health problem with high mortality rates and prevalence. Thus, innovative treatment approaches need to be developed. Biogenic nanoparticles are nanomaterials that can be synthesised in biological systems and, compared to chemically synthesised nanoparticles, have better bioavailability while being more cost-effective, eco-friendlier, and less toxic. In our previous studies, the probiotic strain Lactobacillus casei ATCC 393 was used to synthesise selenium nanoparticles (SeNps), which were shown to inhibit colon cancer cell growth in vitro and in vivo. Herein, we have further investigated SeNps' pro-apoptotic activity and their ability to induce immunogenic cell death (ICD) in colon cancer cells. The SeNps' effect on Caco-2 cells growth was examined along with their potential to induce caspase activation. Moreover, the expression of typical pro-apoptotic and ICD markers were examined in SeNps-treated HT29 and CT26 cells by flow cytometry, Western blot, ELISA and fluorescence microscopy. Elevated caspase-3 activation and surface phosphatyldoserine, that subsided upon co-incubation with a pan-caspase inhibitor, were detected in SeNps-treated cells. Furthermore, nanoparticles induced modulation of the expression of various apoptosis-related proteins. We also report the detection of biomarkers involved in ICD, namely the translocation of calreticulin and ERp57, the release of HMGB1 and ATP, and the secretion of pro-inflammatory cytokines from SeNps-treated cells. Moreover, RAW246.7 macrophages exhibited a higher rate of phagocytosis against treated CT26 when compared to control cells. Taken together, our findings indicate that treatment with SeNps might be an efficient strategy to destroy tumour cells by inducing apoptotic cell death and triggering immune responses.

Antitumor Potential of Lippia citriodora Essential Oil in Breast Tumor-Bearing Mice.

Lippia citriodora is a flowering plant cultivated for its lemon-scented leaves and used in folk medicine for the preparation of tea for the alleviation of symptoms of gastrointestinal disorders, cold, and asthma. The oil extracted from the plant leaves was shown to possess antioxidant potential and to exert antiproliferative activity against breast cancer. The aim of this study was to further investigate potential antitumor effects of L. citriodora oil (LCO) on breast cancer. The in vitro antiproliferative activity of LCO was examined against murine DA3 breast cancer cells by the sulforhodamine B assay. We further explored the LCO's pro-apoptotic potential with the Annexin-PI method. The LCO's anti-migratory effect was assessed by the wound-healing assay. LCO was found to inhibit the growth of DA3 cells in vitro, attenuate their migration, and induce apoptosis. Finally, oral administration of LCO for 14 days in mice inhibited by 55% the size of developing tumors in the DA3 murine tumor model. Noteworthy, in the tumor tissue of LCO-treated mice the apoptotic marker cleaved caspase-3 was elevated, while a reduced protein expression of survivin was observed. These results indicate that LCO, as a source of bioactive compounds, has a very interesting nutraceutical potential.

Antioxidant and Cytoprotective Potential of the Essential Oil Pistacia lentiscus var. chia and Its Major Components Myrcene and α-Pinene.

The antioxidant, cytoprotective, and wound-healing potential of the essential oil from the resin of Pistacia lentiscus var. chia (mastic oil) was evaluated, along with that of its major components, myrcene and α-pinene. Antioxidant potential was monitored as: (i) direct antioxidant activity as assessed by 2,2-di-phenyl-1-picrylhydrazyl (DPPH), 2,2-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid), and ABTS assays; (ii) DNA damage protection activity; and (iii) cytoprotective activity as assessed via induction of transcription of genes related to the antioxidant response in human keratinocyte cells (HaCaT). The cytoprotective potential of the test substances was further evaluated against ultraviolet radiation B (UVB)- or H2O2-induced oxidative damage, whereas their regenerative capability was accessed by monitoring the wound closure rate in HaCaT. Μastic oil and major components did not show significant direct antioxidant activity, however they increased the mRNA levels of antioxidant response genes, suggesting indirect antioxidant activity. Treatment of HaCaT with the test substances before and after UVB irradiation resulted in increased cell viability in the cases of pre-treatment with mastic oil or post-treatment with myrcene. Increased cytoprotection was also observed in the case of cell treatment with mastic oil or its major components prior to H2O2 exposure. Finally, mastic oil and myrcene demonstrated a favorable dose-dependent effect for cell migration and wound closure. Collectively, mastic essential oil may exert its promising cytoprotective properties through indirect antioxidant mechanisms.

Biogenic selenium nanoparticles produced by Lactobacillus casei ATCC 393 inhibit colon cancer cell growth in vitro and in vivo.

Selenium compounds exhibit excellent anticancer properties but have a narrow therapeutic window. Selenium nanoparticles, however, are less toxic compared to other selenium forms, and their biogenic production leads to improved bioavailability. Herein, we used the probiotic strain Lactobacillus casei ATCC 393, previously shown to inhibit colon cancer cell growth, to synthesize biogenic selenium nanoparticles. We examined the anticancer activity of orally administered L. casei, L. casei-derived selenium nanoparticles and selenium nanoparticle-enriched L. casei, and investigated their antitumor potential in the CT26 syngeneic colorectal cancer model in BALB/c mice. Our results indicate that L. casei-derived selenium nanoparticles and selenium nanoparticle-enriched L. casei exert cancer-specific antiproliferative activity in vitro. Moreover, the nanoparticles were found to induce apoptosis and elevate reactive oxygen species levels in cancer cells. It is noteworthy that, when administered orally, selenium nanoparticle-enriched L. casei attenuated the growth of colon carcinoma in mice more effectively than the isolated nanoparticles or L. casei, suggesting a potential additive effect of the nanoparticles and the probiotic. To the best of our knowledge this is the first comparative study examining the anticancer effects of selenium nanoparticles synthesized by a microorganism, the selenium nanoparticle-enriched microorganism and the sole microorganism.

iNOS Expression by Tumor-Infiltrating Lymphocytes, PD-L1 and Prognosis in Non-Small-Cell Lung Cancer.

BACKGROUND: Inducible Nitric Oxygen Synthase (iNOS) promotes the generation of NO in tissues. Its role in tumor progression and immune response is unclear. METHODS: The immunohistochemical expression patterns of iNOS were studied in a series of 98 tissue samples of non-small-cell lung carcinoma (NSCLC), in parallel with the expression of hypoxia and anaerobic metabolism markers, PD-L1 and tumor-infiltrating lymphocytes (TILs). RESULTS: iNOS is expressed by cancer cells in 19/98 (19.4%), while extensive expression by cancer-associated fibroblasts occurs in 8/98 (8.2%) cases. None of these patterns relate to stage or prognosis. Extensive infiltration of the tumor stroma by iNOS-expressing TILs (iNOS+TILs) occurs in 47/98 (48%) cases. This is related to low Hypoxia-Inducible Factor 1α (HIF1α), high PD-L1 expression and a better overall survival (p = 0.002). Expression of PD-L1, however, mitigates the beneficial effect of the presence of iNOS+TIL. CONCLUSIONS: Extensive expression of iNOS by TILs occurs in approximately 50% of NSCLCs, and this is significantly related to an improved overall survival. This brings forward the role of iNOS in anti-neoplastic lymphocyte biology, supporting iNOS+TILs as a putative marker of immune response. The value of this biomarker as a predictive and treatment-guiding tool for tumor immunotherapy demands further investigation.

Modulation of Anti-Tumour Immune Responses by Probiotic Bacteria.

There is a growing amount of evidence to support the beneficial role of a balanced intestinal microbiota, or distinct members thereof, in the manifestation and progression of malignant tumours, not only in the gastrointestinal tract but also in distant tissues as well. Intriguingly, bacterial species have been demonstrated to be indispensable modulatory agents of widely-used immunotherapeutic or chemotherapeutic regiments. However, the exact contribution of commensal bacteria to immunity, as well as to neoplasia formation and response to treatment, has not been fully elucidated, and most of the current knowledge acquired from animal models has yet to be translated to human subjects. Here, recent advances in understanding the interaction of gut microbes with the immune system and the modulation of protective immune responses to cancer, either naturally or in the context of widely-used treatments, are reviewed, along with the implications of these observations for future therapeutic approaches. In this regard, bacterial species capable of facilitating optimal immune responses against cancer have been surveyed. According to the findings summarized here, we suggest that strategies incorporating probiotic bacteria and/or modulation of the intestinal microbiota can be used as immune adjuvants, aiming to optimize the efficacy of cancer immunotherapies and conventional anti-tumour treatments.

Immune Responses Raised in an Experimental Colon Carcinoma Model Following Oral Administration of Lactobacillus casei.

The role of dietary probiotic strains on host anticancer immune responses against experimental colon carcinoma was investigated. We have previously shown that Lactobacillus casei administration led to tumor growth suppression in an experimental colon cancer model. Here, we investigated the underlying immune mechanisms involved in this tumorgrowth inhibitory effect. BALB/c mice received daily live lactobacilli per os prior to the establishment of a syngeneic subcutaneous CT26 tumor. Tumor volume, cytokine production, T cell differentiation and migration, as well as tumor cell apoptosis were examined to outline potential immunomodulatory effects following L. casei oral intake. Probiotic administration in mice resulted in a significant increase in interferon gamma (IFNγ), Granzyme B and chemokine production in the tumor tissue as well as enhanced CD8+ T cell infiltration, accompanied by a suppression of tumor growth. Cytotoxic activity against cancer cells was enhanced in probioticfed compared to control mice, as evidenced by the elevation of apoptotic markers, such as cleaved caspase 3 and poly (ADPribose) polymerase 1 (PARP1), in tumor tissue. Oral administration of Lactobacillus casei induced potent Th1 immune responses and cytotoxic T cell infiltration in the tumor tissue of tumorbearing mice, resulting in tumor growth inhibition. Thus, the microorganism may hold promise as a novel dietary immunoadjuvant in raising protective anticancer immune responses.

Evaluation of Antioxidant and Antiproliferative Properties of Cornus mas L. Fruit Juice.

Cornus mas L. (Cornelian cherry) is a flowering plant indigenous to Europe and parts of Asia, mostly studied for the antimicrobial activity of its juice. In this report, we investigated the composition and the in vitro antioxidant capacity of Cornus mas L. fruit juice from Greece, as well as its antiproliferative properties in vitro and in vivo. The fruits showed a high content of citric, malic, and succinic acid, in contrast to their juice, which had a low concentration of organic acids. The juice demonstrated significant antioxidant activity against the free radical 2,2-diphenyl-1-picrylhydrazyl (DPPH) and modest antiproliferative potential against four human cancer cells lines and one murine: mammary adenocarcinoma MCF-7, hepatocellular carcinoma HepG2 and colon adenocarcinomas Caco2, HT-29, as well as murine colon carcinoma CT26. Cell viability was reduced by 40-50% following incubation of the cells with the highest concentration of the juice. Although Cornelian cherry juice exhibited in vitro growth inhibitory effects against colon carcinoma cells, no tumor growth inhibition was observed in an in vivo experimental colon carcinoma model in mice following prophylactic oral administration of a daily dose of 100 L juice for a period of 10 days. Thus, our findings raise interesting questions for further research on Cornus mas L. fruit juice, and in parallel, the strong antioxidant potential implies that the plant could be further explored and exploited for its protective effect against oxidative damage.

Extraction, Chemical Composition, and Anticancer Potential of Origanum onites L. Essential Oil.

Origanum species are plants rich in volatile oils that are mainly used for culinary purposes. In recent years, there has been a growing interest in the biological activities of their essential oils. Origanum onites L. is a plant mainly found in Greece, Turkey, and Sicily, whose oil is rich in carvacrol, a highly bioactive phytochemical. The aim of this study was to analyze the chemical composition of Origanum onites essential oil (OOEO), and investigate its potential anticancer effects in vitro and in vivo. GC/MS analysis identified carvacrol as OOEO's main constituent. In vitro antiproliferative activity was assayed with the sulforhodamine B (SRB) assay against human cancer cell lines from four tumor types. HT-29, a colorectal cancer cell line, was the most sensitive to the antiproliferative activity of OOEO. Wound-healing assay and Annexin V-PI staining were employed to investigate the antimigratory and the pro-apoptotic potential of OOEO, respectively, against human (HT-29) and murine (CT26) colon cancer cells. Notably, OOEO attenuated migration and induced apoptosis-related morphological changes in both cell lines. Prophylactic oral administration of the oil in a BALB/c experimental mouse model inhibited the growth of syngeneic CT26 colon tumors. As far as we know, this is the first report on the antitumor potential of orally administered OOEO.

Hyperthermia Suppresses Post - In Vitro Proliferation and Tumor Growth in Murine Malignant Melanoma and Colon Carcinoma.

BACKGROUND: Several studies have highlighted hyperthermia's ability to enhance the effectiveness of radiation and chemotherapy in various in vitro and in vivo cancer models. MATERIALS AND METHODS: In vivo murine models of malignant melanoma and colon carcinoma were utilized for demonstrating hyperthermia's therapeutic effectiveness by examining levels of caspase 3, COX-2 and phospho-H2A.X (Ser139) as endpoints of apoptosis, proliferation and DNA damage respectively. RESULTS: Hyperthermia induced in vitro cytotoxicity in malignant melanoma (B16-F10) and colon carcinoma (CT26) cell lines. In addition, it reduced post-in vitro proliferation and suppression of tumor growth by inducing the expression of caspase-3 and phospho-H2A.X (Ser139) while reducing the expression of COX-2 in both murine cancer models. CONCLUSION: Hyperthermia can exert therapeutic effectiveness against melanoma and colon carcinoma by inhibiting a number of critical cellular cascades including apoptosis, proliferation and DNA damage.

Improving the Subcutaneous Mouse Tumor Model by Effective Manipulation of Magnetic Nanoparticles-Treated Implanted Cancer Cells.

Murine tumor models have played a fundamental role in the development of novel therapeutic interventions and are currently widely used in translational research. Specifically, strategies that aim at reducing inter-animal variability of tumor size in transplantable mouse tumor models are of particular importance. In our approach, we used magnetic nanoparticles to label and manipulate colon cancer cells for the improvement of the standard syngeneic subcutaneous mouse tumor model. Following subcutaneous injection on the scruff of the neck, magnetically-tagged implanted cancer cells were manipulated by applying an external magnetic field towards localized tumor formation. Our data provide evidence that this approach can facilitate the formation of localized tumors of similar shape, reducing thereby the tumor size's variability. For validating the proof-of-principle, a low-dose of 5-FU was administered in small animal groups as a representative anticancer therapy. Under these experimental conditions, the 5-FU-induced tumor growth inhibition was statistically significant only after the implementation of the proposed method. The presented approach is a promising strategy for studying accurately therapeutic interventions in subcutaneous experimental solid tumor models allowing for the detection of statistically significant differences between smaller experimental groups.

Pharmacodynamic and Immunomodulatory Effects of Micafungin on Host Responses against Biofilms of Candida parapsilosis in Comparison to Those of Candida albicans.

Micafungin (MFG) demonstrates potent activity against biofilms of Candida albicans and Candida parapsilosis, the most frequent opportunistic fungal pathogens. Little is known about its immunopharmacologic effect on antibiofilm activity of phagocytic cells following exposure to Candida biofilms. In this study, we investigated the effects of MFG on human neutrophil-mediated damage of C. albicans and C. parapsilosis biofilms by XTT [2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide] and the potential mechanisms underlying the immunomodulatory MFG activities on cultured monocyte-derived THP-1 cells in response to these biofilms by reverse transcription-PCR and sandwich and multiplex enzyme-linked immunosorbent assay. Preexposure of C. albicans to subinhibitory MFG concentrations significantly enhanced neutrophil-mediated biofilm damage, an effect that appears to be species specific since a comparable effect was not observed with drug-pretreated C. parapsilosis biofilms. Human THP-1 cells responded to both Candida biofilms through Toll-like receptor 2 (TLR2) and TLR4 upregulation, modest TLR6 involvement, and enhanced NLRP3 activation, whereas the signal was relayed to the nucleus via NF-κB p65 activation. MFG caused 2- to 3-fold lower TLR2 and TLR4 mRNA levels than those caused by either organism. C. albicans biofilms induced a robust proinflammatory response, whereas C. parapsilosis biofilms either alone or in the presence of MFG caused increased interleukin-1ß (IL-1ß) production, but small amounts of IL-8, IL-23, and tumor necrosis factor alpha. In conclusion, MFG may condition THP-1 cells toward an inflammatory response through TLR2/TLR4 recruitment. Inflammatory signals observed with C. albicans biofilms are considerably reduced upon exposure of THP-1 cells to C. parapsilosis biofilms, possibly enhancing fungal survival and increasing biofilm pathogenicity.

Chemical Composition and Evaluation of the Biological Properties of the Essential Oil of the Dietary Phytochemical Lippia citriodora.

The aim of the study was to characterize the chemical composition and biological properties of the essential oil from the plant Lippia citriodora grown in Greece. The essential oil volatiles were analyzed by gas chromatography-mass spectrometry GC-MS indicating citral as the major component. Τhe antimicrobial properties were assayed using the disk diffusion method and the minimum inhibitory and non-inhibitory concentration values were determined. Listeria monocytogenes, Staphylococcus epidermidis, Staphylococcus aureus, Saccharomyces cerevisiae, and Aspergillus niger were sensitive to Lippia citriodora oil, but not Escherichia coli, Salmonella Enteritidis, Salmonella typhimurium, and Pseudomonas fragi. Adversely, all microbes tested were sensitive to citral. 2,2-Diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) assays were used to assess direct antioxidant activity, which proved to be weak for both agents, while comet assay was utilized to study the cytoprotective effects against H2O2-induced oxidative damage in Jurkat cells. Interestingly, the oil showed a more profound cytoprotective effect compared to citral. The antiproliferative activity was evaluated in a panel of cancer cell lines using the sulforhodamine B (SRB) and 2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)-S-(phenylamino) carbonyl-2-tetrazolium hydroxide (XTT) assays and both agents demonstrated potent antiproliferative activity with citral being more cytotoxic than the oil. Taken together, the essential oil of Lippia citriodora and its major component, citral, exert diverse biological properties worthy of further investigation.