The Role And Mechanism Of S100A11in Laryngeal And Hypopharyngeal Squamous Cell Carcinoma

Backgrounds: Head and neck squamous cell carcinoma (HNSCC) is an aggressivemalignancy and has a high metastatic potential. Worldwide, more than a half millionpatients receive a diagnosis of head and neck squamous cell carcinoma each year. In China,the incidence of laryngeal squamous cell carcinoma has been rising gradually, especially inthe Northeast. Early laryngeal cancer can usually be managed successfully with eitherradiotherapy or surgery. However, the advanced stages are still associated with devastatingprognosis and real progress in treatment has still not been achieved, despite advancedsurgical techniques, new chemotherapeutic drugs and improvements in radiotherapy withinthe last30years. About95%of the primary hypopharyngeal cancer is squamous cellcarcinoma. As hypopharynx anatomical location is hidden, malignant lesions are difficultto be found. And it is prone to invasion and metastasis to the surrounding. Important goalsfor cancer research are the identification of molecular signatures and the understanding ofthe mechanisms of tumor progression and metastasis, which might facilitate theidentification of new predictive and prognostic markers for the early detection, prognosis,and response to treatment of carcinoma.The S100proteins, which are small, acidic proteins of10-12kDa in size, are foundexclusively in vertebrates, are among the20members of the multigenic EF hand calciumbinding family of proteins and are each coded by separate genes. S100A11is a member ofthe S100proteins family and it is first identified in1991in chicken gizzard smooth muscle.The gene that codes S100A11, which is also called S100C or calgizzarin, is located onchromosome1q21. The involvement of S100A11has been suggested in a wide range ofbiological processes such as cell growth and motility, cell cycle progression, transcription,differentiation and smooth muscle cell migration. However, it appears to display uniqueproperties and have distinct roles depending on the tumor type. For instance, S100A11isoverexpressed in prostate cancer, uterine leiomyosarcoma, cholangiocarcinoma, colorectalcarcinoma and non small cell lung cancer. In contrast, recent studies have shown that lowS100A11expression was associated with poor survival rates in bladder cancer patients,which suggests a more complex role for S100A11in carcinogenesis. However, theexpression of S100A11and its exact function in laryngeal squamous cell carcinoma andhypopharyngeal squamous cell carcinoma have not been elucidated. Additionally, it appears that none of the previous studies of S100A11have been conducted in laryngealand hypopharyngeal squamous cell carcinoma.Objectives: The protein and mRNA expression levels of S100A11were analyzed inprimary tumors and matched tumor adjacent tissues of laryngeal and hypopharyngealsquamous cell carcinoma. We investigated the mechanisms that overexpression ofS100A11in squamous cell carcinoma of the larynx and hypopharynx influenced themetastasis and development. We silenced S100A11in human larynx epidermal carcinomacell line Hep-2cells and pharyngeal squamous cell carcinoma FaDu cells using smallinterfering RNA, and studied the influence of the proliferation and migration of Hep-2andFaDu cells when S100A11was inhibited.Methods: The protein and mRNA expression levels of S100A11were analyzed in primarytumors and matched tumor adjacent tissues of laryngeal and hypopharyngeal squamouscell carcinoma by western blotting and semi-quantitative reverse transcription polymerasechain reaction (RT-PCR) or quantitative real time PCR (Q-RT-PCR), respectively.S100A11knockdown experiments were performed by the transfection of S100A11smallinterfering RNA (siRNA) in human laryngeal carcinoma Hep-2cells and pharyngealsquamous cell carcinoma FaDu cells with Lipofectamine2000. Cell proliferation abilitywas determined by Cell Counting Kit-8assay (cck-8) and colony formation assay. And theinvasiveness ability was detected by the transwell migration assay and scratch migrationassay. These experiments were performed to assess whether knockdown of S100A11bysmall interfering RNA (siRNA) could influence the biological behavior of human laryngealcarcinoma Hep-2cells and pharyngeal squamous cell carcinoma FaDu cells in vitro.Results: We found that both protein and mRNA levels of S100A11were overexpressed inlaryngeal and hypopharyngeal tumor tissues when compared to the correspondingnoncancerous tissues (P<0.05). Further, transwell and scratch migration assays weredemonstrated that the expression of S100A11could induce migration but not proliferationof Hep-2and FaDu cells. Additionally, knockdown of S100A11altered a series ofintracellular events, including the down-regulation of epidermal growth factor receptor(EGFR), CD44, MMP2and MMP9.Conclusion: These results highlight the significance of S100A11in laryngeal andhypopharyngeal squamous cell carcinoma progression and suggest that S100A11might bean important regulatory protein in the promotion of migration of laryngeal andhypopharyngeal squamous cell carcinoma. Our study provided useful information toward an elucidation of the molecular mechanisms of tumor metastasis and the development ofclinically relevant biomarkers for metastasis prevention.