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Cisplatin (CDDP) is a useful drug for the treatment of malignant solid tumors of the head and neck. Because CDDP includes the heavy metal platinum as a component, it is thought metallothionein (MT) may be involved in CDDP-resistance. However, functional differences between the four MT isoforms (MT-I, II, III and IV) remain unclear. The aim of this study was to investigate the relationship between MT isoform expression and CDDP-resistance. Two human tongue squamous cell carcinoma cell lines not exposed to anticancer chemotherapy were studied. The cell lines were subjected to reverse transcriptase-polymerase chain reaction (RT-PCR) analysis before and after CDDP-treatment. Both cell lines expressed MT-I/II and MT-IV isoforms but not the MT-III isoform. Following CDDP treatment, MT-I/II mRNA levels were induced only in the CDDP-resistant cell line. Our results showed that expression of the MT I/II isoform was induced by CDDP treatment, and may play an important role in CDDP-resistance in squamous cell carcinoma of the human tongue.

The purpose of this study was to demonstrate the immunohistochemical localization and distribution of human alpha- and beta-defensins, peptides with antimicrobial activity, in oral mucoepidermoid carcinoma tissue. Tissue samples were embedded in paraffin and alpha- and beta-defensins were immunostained by the streptavidin-biotin coupled peroxidase method. Cancer cells that constituted the ducts, as well as neutrophils, were positively immunostained with the anti-alpha-defensin antibody (HNPs). On the other hand, epidermoid cells and intermediate cells were intensely stained with the anti-beta-defensin-2 (HBD-2) antibody. Mucous-secreting cells were clearly not immunostained with the anti-HBD-2 antibody. The epithelial hyperplasia region adjacent to the tumor tissues was also positively immunostained with the anti-HBD-2 antibody.

The purpose of this study was to demonstrate immunohistochemically the localization and distribution of human beta-defensin-2 (HBD-2), a peptide with antimicrobial activity, in oral carcinoma tissues. Tissue samples were embedded in paraffin, and HBD-2 was immunostained by the streptavidin-biotin coupled peroxidase method. Cancer cells in the cornified region of well differentiated squamous cell carcinomas were stained intensely. Stained cancer cells detected by anti-HBD-2 antibody were scattered among the cells of the non-cornified region.

The purpose of this study was the immunohistochemical localization and distribution of HNP-1 in the submandibular glands of patients with oral carcinomas. Tissue sections were embedded in paraffin, and HNP-1 was immunostained by the streptavidin-biotin coupled peroxidase method. Striated duct cells in the submandibular glands were stained with anti-defensin antibody. Neutrophils and capillary intimal cells were also stained. Defensins (HNPs) are peptides that occur in neutrophils and protect against bacteria and tumor cells. Human alpha-defensin-1 (HNP-1) is such a peptide, possessing both antimicrobial and cytotoxic activities. The presence of HNP-1 in striated duct cells in the submandibular glands of oral cancer patients, suggests a likely role in tumor immunity, for this peptide.

The saliva of patients with oral squamous cell carcinoma was subjected to reversed-phase HPLC, and a peak (P 14) was eluted with a linear gradient of acetonitrile. The molecular weight of P14 was 3,442 daltons by mass spectrometry. The results of amino acid sequencing by Edman degradation and homology studies indicated that P14 was consistent with a peptide, human alpha-defensin 1 (HNP-1) which belongs to the defensin family. The concentration of HNP-1 in the saliva of 6 squamous cell carcinoma patients before surgery and 11 after surgery was 12.3 +/- 8.6 and 6.5 +/- 5.9 micrograms/ml (mean +/- S.D.), respectively. In contrast, minimal amounts of HNP-1 were found in the saliva of adenocarcinoma patients and healthy volunteers. The concentration of salivary HNP-1 correlated positively with serum squamous cell carcinoma related antigen (SCC-Ag)level (r = 0.879, p < 0.01).