ABSTRACT
The significance of KDM2B in oncogenesis has been appreciated, but the mechanism behind is incompletely understood. In this work, we addressed its effects on the progression of non-small cell lung cancer (NSCLC). Overexpression of KDM2B was linked to dismal prognoses of NSCLC patients. Based on the expression levels of KDM2B in a panel of NSCLC cell lines, A549, showing lower level of expression, and SK-MES-1, showing higher levels of expression, were selected as model systems to evaluate the effect of KDM2B overexpression and KDM2B silencing, respectively. Knockdown of KDM2B hampered NSCLC cell proliferation, invasion, as well as migration, while enhanced apoptosis. Additionally, KDM2B repressed the expression of microRNA (miR)-let-7b-5p through demethylation modification of H3K36me2, thereby promoting the expression of zester homolog 2 (EZH2), the target gene of let-7b-5p in NSCLC. Moreover, EZH2 transcriptionally induced the expression of PKMYT1 to activate the Wnt/ß-catenin pathway. Sh-EZH2 and sh-PKMYT1 neutralized the supporting effects of KDM2B on cell proliferation, invasion and migration. Additionally, deletion of KDM2B reduced the xenograft volumes in nude mice. In conclusion, KDM2B induces the EZH2/PKMYT1/Wnt/ß-catenin axis by inhibiting the let-7b-5p expression, which promotes NSCLC growth. More investigations are essential to determine the oncogenic role of KDM2B in NSCLC.
Subject(s)
Carcinoma, Non-Small-Cell Lung , F-Box Proteins , Jumonji Domain-Containing Histone Demethylases , Lung Neoplasms , Membrane Proteins , Protein Serine-Threonine Kinases , Protein-Tyrosine Kinases , Animals , Carcinogenesis/genetics , Carcinoma, Non-Small-Cell Lung/genetics , Cell Line, Tumor , Cell Movement/genetics , Cell Proliferation/genetics , Enhancer of Zeste Homolog 2 Protein/genetics , Enhancer of Zeste Homolog 2 Protein/metabolism , F-Box Proteins/genetics , F-Box Proteins/metabolism , Gene Expression Regulation, Neoplastic/genetics , Humans , Jumonji Domain-Containing Histone Demethylases/genetics , Jumonji Domain-Containing Histone Demethylases/metabolism , Lung Neoplasms/genetics , Membrane Proteins/genetics , Membrane Proteins/metabolism , Mice , Mice, Nude , MicroRNAs/genetics , Protein Serine-Threonine Kinases/genetics , Protein Serine-Threonine Kinases/metabolism , Protein-Tyrosine Kinases/genetics , Protein-Tyrosine Kinases/metabolism , Transcriptional Activation , Wnt Signaling Pathway/genetics , beta Catenin/genetics , beta Catenin/metabolismABSTRACT
BACKGROUND/AIMS: The mineral-dust-induced gene mdig is a lung-cancer-associated oncogene. The focus of this study is to evaluate the expression status of mdig in lung cancer and to assess its influence in predicting the patient's overall survival. METHODS: Using high-density tissue microarrays and clinical samples of synchronous multiple primary lung cancer (SMPLC), we investigated the expression of mdig through immunohistochemistry and utilized the open-access lung cancer patient databases containing genomic and transcriptomic data from the UCSC Xena and TCGA web platforms to determine the prognostic values of mdig expression status among different subtypes of lung cancer. RESULTS: mdig is upregulated in smokers and in lung squamous cell carcinoma. High mdig expression predicted poor overall survival in lung squamous cell carcinoma and female smokers. Among tumor tissues from SMPLC patients, we not only unraveled the highest positive rate of mdig expression, but also revealed a unique cytoplasmic, rather than nuclear localization of mdig protein. Furthermore, by inspecting some pathological but not cancerous lung tissues, we believe that mdig is required for the transformation of non-cancerous lung cells to the fully-fledged cancer cells. CONCLUSION: These data suggested that mdig is involved in various stages of lung carcinogenesis, possibly through the epigenetic regulation on some critical cancer-associated genes, and increased mdig expression is an important prognostic factor for some types of lung cancer.
