Salivary glands defensin

Transduction of salivary glands with antimicrobial peptide genes has great potential for oral infection control. Our ultimate goal is to introduce antimicrobial peptide genes into salivary glands that secrete these peptides into saliva to control bacterial/fungal infection in the oral cavity. However, an animal study model to test this potential has not been established. Therefore, we determined to test (i) whether the potent antimicrobial peptide human beta-defensin-2 (hBD-2) can be overexpressed in saliva after transduction of salivary glands and (ii) whether oral fungal infection can be developed in a NOD/SCID murine model. Lentiviral vector SIN18cPPTRhMLV bearing hBD-2 cDNA was introduced into SCID mouse submandibular glands via cannulation. Reverse transcription polymerase chain reaction (RT-PCR), immunohistochemistry or enzyme-linked immunosorbent assay (ELISA) were performed to detect hBD-2 expression in glands or in saliva. Candida albicans 613p was inoculated orally into SCID mice to establish oral candidiasis. Whilst expression of hBD-2 was detected in mouse salivary glands by RT-PCR and immunohistochemistry 1 day or 1 week following delivery of lentivirus, hBD-2 was not detected in saliva. There was recoverable C. albicans from the oral cavity and gastrointestinal tract 4 days to 4 weeks after infection, but there was no establishment of observable oral candidiasis in SCID mice under a stereomicroscope. Our data indicate that lentiviral vectors transduce mouse salivary glands, but not at a sufficient level to allow hBD-2 detection in saliva. Other vectors for gene transduction and additional treatment of SCID mice to establish oral candidiasis are needed in order to utilise mouse salivary glands to test antimicrobial gene therapy.

There is increasing evidence for an association between periodontitis/tooth loss and oral, gastrointestinal, and pancreatic cancers. Periodontal disease, which is characterized by chronic inflammation and microbial dysbiosis, is a significant risk factor for orodigestive carcinogenesis. Porphyromonas gingivalis is proposed as a keystone pathogen in chronic periodontitis causing both dysbiosis and discordant immune response. The present review focuses on the growing recognition of a relationship between P. gingivalis and orodigestive cancers. Porphyromonas gingivalis has been recovered in abundance from oral squamous cell carcinoma (OSCC). Recently established tumorigenesis models have indicated a direct relationship between P. gingivalis and carcinogenesis. The bacterium upregulates specific receptors on OSCC cells and keratinocytes, induces epithelial-to-mesenchymal (EMT) transition of normal oral epithelial cells and activates metalloproteinase-9 and interleukin-8 in cultures of the carcinoma cells. In addition, P. gingivalis accelerates cell cycling and suppresses apoptosis in cultures of primary oral epithelial cells. In oral cancer cells, the cell cycle is arrested and there is no effect on apoptosis, but macro autophagy is increased. Porphyromonas gingivalis promotes distant metastasis and chemoresistance to anti-cancer agents and accelerates proliferation of oral tumor cells by affecting gene expression of defensins, by peptidyl-arginine deiminase and noncanonical activation of β-catenin. The pathogen also converts ethanol to the carcinogenic intermediate acetaldehyde. In addition, P. gingivalis can be implicated in precancerous gastric and colon lesions, esophageal squamous cell carcinoma, head and neck (larynx, throat, lip, mouth and salivary glands) carcinoma, and pancreatic cancer. The fact that distant organs can be involved clearly emphasizes that P. gingivalis has systemic tumorigenic effects in addition to the local effects in its native territory, the oral cavity. Although coinfection with other bacteria, viruses, and fungi occurs in periodontitis, P. gingivalis relates to cancer even in absence of periodontitis. Thus, there may be a direct relationship between P. gingivalis and orodigestive cancers.

Oral cancers are the sixth most frequent cancer with a high mortality rate. Oral squamous cell carcinoma accounts for more than 90% of all oral cancers. Standard methods used to detect oral cancers remain comprehensive clinical examination, expensive biochemical investigations, and invasive biopsy. The identification of biomarkers from biological fluids (blood, urine, saliva) has the potential of early diagnosis. The use of saliva for early cancer detection in the search for new clinical markers is a promising approach because of its noninvasive sampling and easy collection methods. Human whole-mouth saliva contains proteins, peptides, electrolytes, organic, and inorganic salts secreted by salivary glands and complimentary contributions from gingival crevicular fluids and mucosal transudates. This diagnostic modality in the field of molecular biology has led to the discovery and potential of salivary biomarkers for the detection of oral cancers. Biomarkers are the molecular signatures and indicators of normal biological, pathological process, and pharmacological response to treatment hence may provide useful information for detection, diagnosis, and prognosis of the disease. Saliva's direct contact with oral cancer lesions makes it more specific and potentially sensitive screening tool, whereas more than 100 salivary biomarkers (DNA, RNA, mRNA, protein markers) have already been identified, including cytokines (IL-8, IL-1b, TNF-α), defensin-1, P53, Cyfra 21-1, tissue polypeptide-specific antigen, dual specificity phosphatase, spermidine/spermineN1-acetyltransferase , profilin, cofilin-1, transferrin, and many more. However, further research is still required for the reliability and validation of salivary biomarkers for clinical applications. This chapter provides the latest up-to-date list of known and emerging potential salivary biomarkers for early diagnosis of oral premalignant and cancerous lesions and monitoring of disease activity.