Head and neck cancer comprises predominantly squamous cell carcinomas and affects the oral cavity, larynx, and pharynx. Head and neck squamous cell carcinoma (HNSCC) is the sixth most common cancer worldwide with 550.000 new cases every year. Matriptase, a type II transmembrane serine protease, induces malignant transformation when expressed in epithelial stem cells. It has been recently shown that PI3K-Akt-mTor signaling, elicited by proteolytic activation of pro-hepatocyte growth factor, is one molecular pathway by which matriptase promotes malignant transformation. Another essential component of matriptase-mediated oncogenesis is the upregulation of NFkB-induced inflammatory cytokines that are dependent on the PAR-2 proteolytic cleavage by matriptase. Moreover, it has been demonstrated that matriptase-dependent activation of kallikreins 5 and 7, during terminal differentiation of keratinocytes, is inhibited by the serine protease inhibitor LEKTI. Preliminary data from our laboratory show that LEKTI is predominantly expressed by well differentiated cells, in human oral squamous cell carcinomas. Moreover, other preliminary results from our group suggest that LEKTI expression is upregulated in the epithelia, when matriptase is expressed in epithelial stem cells. Therefore, we aim on testing the hypothesis in which matriptase-dependent proteolytic pathway is inhibited by LEKTI in carcinomas. In order to test this hypothesis, we have been using transgenic mice that express LEKTI and matriptase, under the control of keratin 5 promoter (K5-LEKTI and K5-Mat mice, respectively). Preliminary data has been very promising and shows a 100% rescue of K5-Mat premalignant phenotype in double transgenic mice (K5-LEKTI/K5-Mat), when K5-LEKTI mice are bred to K5-Mat mice. Since LEKTI is unable to directly inhibit matriptase, we hypothesized that there is a third matriptase target, in addition to pro-HGF and PAR-2, in malignant epithelial neoplasia. In this respect, LEKTI inhibition of matriptase-dependent proteolytic pathway could occur, for instance, through the inhibition of epithelial kallikreins. Using in vivo genetic manipulation, accompanied by histological evaluation and molecular signature analysis of murine biopsies, in addition to in vitro cell-based assays; we aim to uncover the genetic and cellular mechanisms involved in matriptase-dependent malignant transformation, with emphasis on the inhibitory role of LEKTI. The results obtained in this study will be associated with results of other current project of our group where the expression of LEKTI and epithelial kallikreins are being immunohistochemically evaluated in biopsies of human oral squamous cell carcinomas.
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(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)
ALVES, MARCIA GAIAO;
KODAMA, MARCIO HIDEKI;
MARCELINO DA SILVA, ELAINE ZAYAS;
MARTINELLI GOMES, BRUNO BELMONTE;
ALVES DA SILVA, RODRIGO ALBERTO;
VIEIRA, GABRIEL VILIOD;
ALVES, VANI MARIA;
DA FONSECA, CAROL KOBORI;
SANTANA, ANA CAROLINA;
CECILIO, NERRY TATIANA;
ALEXANDRE COSTA, MARA SILVIA;
JAMUR, MARIA CELIA;
CUNHA, THIAGO MATTAR;
BUGGE, THOMAS H.;
BRAZ-SILVA, PAULO HENRIQUE;
COLLI, LEANDRO M.;
SALES, KATIUCHIA UZZUN.
Relative expression of KLK5 to LEKTI is associated with aggressiveness of oral squamous cell carcinoma.
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