Emerging therapeutic modality enhancing the efficiency of chemotherapeutic agents against head and neck squamous cell carcinoma cell lines.

The current work aimed to evaluate bee venom (BV) cytotoxic effect and its synergistic action when combined with cisplatin (CIS) against four types of head and neck squamous cell carcinoma (HNSCC) cell lines. 3-(4,5-dimethylthiazol-2-Yl)-2,5-diphenyltetrazolium bromide (MTT) assay for cell viability, reverse transcription-polymerase chain reaction (RT-PCR) for expression of BCL2 associated X (BAX), B-cell lymphoma 2 (BCL2) and epidermal growth factor receptor (EGFR) genes and, flow cytometry for cell cycle analysis were performed. MTT assay revealed that BV caused an approximately 50% cell death for UMSCC12, UMSCC29, UMSCC38 and, UMSCC47 cell lines after 72 hr with 54.809 µg/ml, 61.287 µg/ml, 71.328 µg/ml and, 61.045 µg/ml, respectively. RT-PCR demonstrated a significant up-regulation of BAX gene and a significant down-regulation of BCL2 and EGFR genes among single or combined treatments with CIS and BV as compared to vehicle-treated. The cell lines treated with both BV and CIS showed marked elevation of BAX and a notable drop of BCL2 and EGFR expressions than single-treated groups. Cell cycle analysis via flow cytometry revealed significantly increased cells in the G2/M phase in single or combined-treated cell lines with CIS and BV when compared with vehicle-treated. Moreover, a significant decrease in cells in S phases among all single and combined treatments when matched with vehicle-treated. Briefly, the findings of the present study suggest that BV can exert an anti-cancer effect on HNSCC and may have the potentiality for potentiation of CIS cytotoxic effects and reduction of its adverse effects.

Periodontal pathogens promote cancer aggressivity via TLR/MyD88 triggered activation of Integrin/FAK signaling that is therapeutically reversible by a probiotic bacteriocin.

Epidemiological studies reveal significant associations between periodontitis and oral cancer. However, knowledge about the contribution of periodontal pathogens to oral cancer and potential regulatory mechanisms involved is limited. Previously, we showed that nisin, a bacteriocin and commonly used food preservative, reduced oral cancer tumorigenesis and extended the life expectancy in tumor-bearing mice. In addition, nisin has antimicrobial effects on key periodontal pathogens. Thus, the purpose of this study was to test the hypothesis that key periodontal pathogens (Porphyromonas gingivalis, Treponema denticola, and Fusobacterium nucleatum) promote oral cancer via specific host-bacterial interactions, and that bacteriocin/nisin therapy may modulate these responses. All three periodontal pathogens enhanced oral squamous cell carcinoma (OSCC) cell migration, invasion, tumorsphere formation, and tumorigenesis in vivo, without significantly affecting cell proliferation or apoptosis. In contrast, oral commensal bacteria did not affect OSCC cell migration. Pathogen-enhanced OSCC cell migration was mediated via integrin alpha V and FAK activation, since stably blocking alpha V or FAK expression abrogated these effects. Nisin inhibited these pathogen-mediated processes. Further, Treponema denticola induced TLR2 and 4 and MyD88 expression. Stable suppression of MyD88 significantly inhibited Treponema denticola-induced FAK activation and abrogated pathogen-induced migration. Together, these data demonstrate that periodontal pathogens contribute to a highly aggressive cancer phenotype via crosstalk between TLR/MyD88 and integrin/FAK signaling. Nisin can modulate these pathogen-mediated effects, and thus has therapeutic potential as an antimicrobial and anti-tumorigenic agent.

Evaluation of the osteogenic potential of rat adipose-derived stem cells with different polycaprolactone/alginate-based nanofibrous scaffolds: an in vitro study.

BACKGROUND: Bone tissue engineering is a widely growing field that requires the combination of cells, scaffolds and signaling molecules. Adipose derived stem cells (ADSCs) are an accessible and abundant source of mesenchymal stem cells with high plasticity. Polycaprolactone/alginate (PCL/Alg) composite scaffolds have been used in bone regeneration and nano-hydroxyapatite (n-HA) is used as a reinforcing, osteoconductive component in scaffold fabrication. This study was conducted to assess the ability of three different PCL/Alg based scaffolds to induce osteogenic differentiation of ADSCs and to compare between them. METHODS: The study comprised 5 groups; negative control group with ADSCs cultured in complete culture media, positive control group with ADSCs cultured in osteogenic differentiation media, and 3 experimental groups with ADSCs seeded onto 3 scaffolds: S1 (PCL/Alg), S2 (PCL/Alg/Ca) and S3 (PCL/Alg/Ca/n-HA) respectively and cultured in osteogenic media. Mineralization and gene expression were assessed by Alizarin red S (ARS) staining and real time quantitative polymerase chain reaction (RT-qPCR). Evaluation was done at 7, 14 and 21 days. RESULTS: ARS staining reflected a time dependent increase through days 7, 14 and 21, with S3 (PCL/Alg/Ca/n-HA) group showing the highest mineralization levels. RT-qPCR detected upregulation of ALP gene expression at day 7 and decline thereafter. S2 (PCL/Alg/Ca) and S3 (PCL/Alg/Ca/n-HA) groups showed significantly higher gene expression levels than S1 (PCL/Alg). CONCLUSIONS: ADSCs and PCL/Alg-based scaffolds compose a good tissue engineering complex for bone regeneration. Addition of n-HA to PCL/Alg scaffolds and crosslinking with CaCl2 efficiently improve the osteogenic potential of ADSCs.

Treponema denticola increases MMP-2 expression and activation in the periodontium via reversible DNA and histone modifications.

Host-derived matrix metalloproteinases (MMPs) and bacterial proteases mediate destruction of extracellular matrices and supporting alveolar bone in periodontitis. The Treponema denticola dentilisin protease induces MMP-2 expression and activation in periodontal ligament (PDL) cells, and dentilisin-mediated activation of pro-MMP-2 is required for cellular fibronectin degradation. Here, we report that T. denticola regulates MMP-2 expression through epigenetic modifications in the periodontium. PDL cells were treated with epigenetic enzyme inhibitors before or after T. denticola challenge. Fibronectin fragmentation, MMP-2 expression, and activation were assessed by immunoblot, zymography, and qRT-PCR, respectively. Chromatin modification enzyme expression in T. denticola-challenged PDL cells and periodontal tissues were evaluated using gene arrays. Several classes of epigenetic enzymes showed significant alterations in transcription in diseased tissue and T. denticola-challenged PDL cells. T. denticola-mediated MMP-2 expression and activation were significantly reduced in PDL cells treated with inhibitors of aurora kinases and histone deacetylases. In contrast, DNA methyltransferase inhibitors had little effect, and inhibitors of histone acetyltransferases, methyltransferases, and demethylases exacerbated T. denticola-mediated MMP-2 expression and activation. Chronic epigenetic changes in periodontal tissues mediated by T. denticola or other oral microbes may contribute to the limited success of conventional treatment of chronic periodontitis and may be amenable to therapeutic reversal.

Antimicrobial nisin acts against saliva derived multi-species biofilms without cytotoxicity to human oral cells.

OBJECTIVES: Nisin is a lantibiotic widely used for the preservation of food and beverages. Recently, investigators have reported that nisin may have clinical applications for treating bacterial infections. The aim of this study was to investigate the effects of ultra pure food grade Nisin ZP (>95% purity) on taxonomically diverse bacteria common to the human oral cavity and saliva derived multi-species oral biofilms, and to discern the toxicity of nisin against human cells relevant to the oral cavity. METHODS: The minimum inhibitory concentrations and minimum bactericidal concentrations of taxonomically distinct oral bacteria were determined using agar and broth dilution methods. To assess the effects of nisin on biofilms, two model systems were utilized: a static and a controlled flow microfluidic system. Biofilms were inoculated with pooled human saliva and fed filter-sterilized saliva for 20-22 h at 37°C. Nisin effects on cellular apoptosis and proliferation were evaluated using acridine orange/ethidium bromide fluorescent nuclear staining and lactate dehydrogenase activity assays. RESULTS: Nisin inhibited planktonic growth of oral bacteria at low concentrations (2.5-50 µg/ml). Nisin also retarded development of multi-species biofilms at concentrations ≥1 µg/ml. Specifically, under biofilm model conditions, nisin interfered with biofilm development and reduced biofilm biomass and thickness in a dose-dependent manner. The treatment of pre-formed biofilms with nisin resulted in dose- and time-dependent disruption of the biofilm architecture along with decreased bacterial viability. Human cells relevant to the oral cavity were unaffected by the treatment of nisin at anti-biofilm concentrations and showed no signs of apoptotic changes unless treated with much higher concentrations (>200 µg/ml). CONCLUSION: This work highlights the potential therapeutic value of high purity food grade nisin to inhibit the growth of oral bacteria and the development of biofilms relevant to oral diseases.