Epigenetic alterations leading to TMPRSS4 promoter hypomethylation and protein overexpression predict poor prognosis in squamous lung cancer patients

Non-small cell lung cancer (NSCLC) is the leading cause of cancer-related death worldwide, which highlights the need of innovative therapeutic options. Although targeted therapies can be successfully used in a subset of patients with lung adenocarcinomas (ADC), they are not appropriate for patients with squamous cell carcinomas (SCC). In addition, there is an unmet need for the identification of prognostic biomarkers that can select patients at risk of relapse in early stages. Here, we have used several cohorts of NSCLC patients to analyze the prognostic value of both protein expression and DNA promoter methylation status of the prometastatic serine protease TMPRSS4. Moreover, expression and promoter methylation was evaluated in a panel of 46 lung cancer cell lines. We have demonstrated that a high TMPRSS4 expression is an independent prognostic factor in SCC. Similarly, aberrant hypomethylation in tumors, which correlates with high TMPRSS4 expression, is an independent prognostic predictor in SCC. The inverse correlation between expression and methylation status was also observed in cell lines. In vitro studies showed that treatment of cells lacking TMPRSS4 expression with a demethylating agent significantly increased TMPRSS4 levels. In conclusion, TMPRSS4 is a novel independent prognostic biomarker regulated by epigenetic changes in SCC and a potential therapeutic target in this tumor type, where targeted therapy is still underdeveloped

Development of biological tools to assess the role of TMPRSS4 and identification of novel tumor types with high expression of this prometastatic protein

Metastatic spread is responsible for the majority of cancer deaths and identification of metastasisrelated therapeutic targets is compulsory. TMPRSS4 is a pro-metastatic druggable transmembrane type II serine protease whose expression has been associated with the development of several cancer types and poor prognosis. To study the role and expression of this protease in cancer, we have developed molecular tools (active recombinant proteins and a polyclonal antibody) that can be used for diagnostic purposes and for testing anti-TMPRSS4 drugs. In addition, we have evaluated TMPRSS4 protein expression in several cancer tissue microarrays (TMAs). Full length and truncated TMPRSS4 recombinant proteins maintained the catalytic activity in two different expression systems (baculovirus and E. coli). Sensitivity of the rabbit polyclonal antisera against TMPRSS4 (ING-pAb) outperformed the antibody most commonly used in clinical settings. Analysis by immunohistochemistry in the different TMAs identified a subset of adenocarcinomas, squamous carcinomas, large cell carcinomas and carcinoids of the lung, in which TMPRSS4 expression may define aggressive tumors. In conclusion, our biological tools will help the characterization of TMPRSS4 activity and protein expression, as well as the evaluation of anti-TMPRSS4 drugs. Future studies should determine the clinical value of assessing TMPRSS4 levels in different types of lung cancer

Epigenetic alterations leading to TMPRSS4 promoter hypomethylation and protein overexpression predict poor prognosis in squamous lung cancer patients

Non-small cell lung cancer (NSCLC) is the leading cause of cancer-related death worldwide, which highlights the need of innovative therapeutic options. Although targeted therapies can be successfully used in a subset of patients with lung adenocarcinomas (ADC), they are not appropriate for patients with squamous cell carcinomas (SCC). In addition, there is an unmet need for the identification of prognostic biomarkers that can select patients at risk of relapse in early stages. Here, we have used several cohorts of NSCLC patients to analyze the prognostic value of both protein expression and DNA promoter methylation status of the prometastatic serine protease TMPRSS4. Moreover, expression and promoter methylation was evaluated in a panel of 46 lung cancer cell lines. We have demonstrated that a high TMPRSS4 expression is an independent prognostic factor in SCC. Similarly, aberrant hypomethylation in tumors, which correlates with high TMPRSS4 expression, is an independent prognostic predictor in SCC. The inverse correlation between expression and methylation status was also observed in cell lines. In vitro studies showed that treatment of cells lacking TMPRSS4 expression with a demethylating agent significantly increased TMPRSS4 levels. In conclusion, TMPRSS4 is a novel independent prognostic biomarker regulated by epigenetic changes in SCC and a potential therapeutic target in this tumor type, where targeted therapy is still underdeveloped