A signal-based method for finding driver modules of breast cancer metastasis to the lung

Protein interaction networks characterizing the A549 cells Klotho transfected are associated with activated pro-apoptotic Bim and suppressed Wnt/β-catenin signaling pathway

Invasive assays and lung tumor-bearing mice models using a human lung adenocarcinoma cell line A549 cells transfected with the Klotho (KL) gene, A549/KL cells, have confirmed that KL suppresses invasive/metastatic potential. This study aimed to identify the co-expression protein networks and proteomic profiles associated with A549/KL cells to understand how Klotho protein expression affects molecular networks associated with lung carcinoma malignancy. A two-step application of a weighted network correlation analysis to the cells' quantitative proteome datasets of a total of 6,994 proteins, identified by mass spectrometry-based proteomic analysis with data-independent acquisition (DIA), identified one network module as most significantly associated with the A549/KL trait. Upstream analyses, confirmed by western blot, implicated the pro-apoptotic Bim (Bcl-2-like protein 11) as a master regulator of molecular networks affected by Klotho. GeneMANIA interaction networks and quantitative proteome data implicated that Klotho interacts with two signaling axes: negatively with the Wnt/β-catenin axis, and positively by activating Bim. Our findings might contribute to the development of future therapeutic strategies.

Bioinformatics analysis of the genes involved in the extension of prostate cancer to adjacent lymph nodes by supervised and unsupervised machine learning methods: The role of SPAG1 and PLEKHF2

The present study aimed to identify the genes associated with the involvement of adjunct lymph nodes of patients with prostate cancer (PCa) and to provide valuable information for the identification of potential diagnostic biomarkers and pathological genes in PCa metastasis. The most important candidate genes were identified through several machine learning approaches including K-means clustering, neural network, Naïve Bayesian classifications and PCA with or without downsampling. In total, 21 genes associated with lymph nodes involvement were identified. Among them, nine genes have been identified in metastatic prostate cancer, six have been found in the other metastatic cancers and four in other local cancers. The amplification of the candidate genes was evaluated in the other PCa datasets. Besides, we identified a validated set of genes involved in the PCa metastasis. The amplification of SPAG1 and PLEKHF2 genes were associated with decreased survival in patients with PCa.

IRSp53 coordinates AMPK and 14-3-3 signaling to regulate filopodia dynamics and directed cell migration

Filopodia are actin-filled membrane protrusions that play essential roles in cell motility and cell–cell communication and act as precursors of dendritic spines. IRSp53 is an essential regulator of filopodia formation, which couples Rho-GTPase signaling to actin cytoskeleton and membrane remodeling. IRSp53 has three major domains: an N-terminal inverse-BAR (I-BAR) domain, a Cdc42- and SH3-binding CRIB-PR domain, and an SH3 domain that binds downstream cytoskeletal effectors. Phosphorylation sites in the region between the CRIB-PR and SH3 domains mediate the binding of 14-3-3. Yet the mechanism by which 14-­3-3 regulates filopodia formation and dynamics and its role in cell migration are poorly understood. Here, we show that phosphorylation-dependent inhibition of IRSp53 by 14-3-3 counters activation by Cdc42 and cytoskeletal effectors, resulting in down-regulation of filopodia dynamics and cancer cell migration. In serum-starved cells, increased IRSp53 phosphorylation triggers 14-3-3 binding, which inhibits filopodia formation and dynamics, irrespective of whether IRSp53 is activated by Cdc42 or downstream effectors (Eps8, Ena/VASP). Pharmacological activation or inhibition of AMPK, respectively, increases or decreases the phosphorylation of two of three sites in IRSp53 implicated in 14-3-3 binding. Mutating these phosphorylation sites reverses 14-3-3-dependent inhibition of filopodia dynamics and cancer cell chemotaxis.

Activation of hepatocyte growth factor/MET signaling initiates oncogenic transformation and enhances tumor aggressiveness in the murine prostate

Emerging evidence has shown that the hepatocyte growth factor (HGF) and its receptor, MET proto-oncogene, receptor tyrosine kinase (MET), promote cell proliferation, motility, morphogenesis, and angiogenesis. Whereas up-regulation of MET expression has been observed in aggressive and metastatic prostate cancer, a clear understanding of MET function in prostate tumorigenesis remains elusive. Here, we developed a conditional Met transgenic mouse strain, H11 ^Met/+ :PB-Cre4, to mimic human prostate cancer cells with increased MET expression in the prostatic luminal epithelium. We found that these mice develop prostatic intraepithelial neoplasia after HGF administration. To further assess the biological role of MET in prostate cancer progression, we bred H11 ^Met/+ /Pten^LoxP/LoxP:PBCre4 compound mice, in which transgenic Met expression and deletion of the tumor suppressor gene Pten occurred simultaneously only in prostatic epithelial cells. These compound mice exhibited accelerated prostate tumor formation and invasion as well as increased metastasis compared with Pten^LoxP/LoxP:PB-Cre4 mice. Moreover, prostatic sarcomatoid carcinomas and lesions resembling the epithelial-to-mesenchymal transition developed in tumor lesions of the compound mice. RNA-Seq and qRT-PCR analyses revealed a robust enrichment of known tumor progression and metastasis-promoting genes in samples isolated from H11 ^Met/+ /Pten^LoxP/LoxP:PB-Cre4 compound mice compared with those from Pten^LoxP/LoxP:PB-Cre4 littermate controls. HGF-induced cell proliferation and migration also increased in mouse embryonic fibroblasts (MEFs) from animals with both Met transgene expression and Pten deletion compared with Pten-null MEFs. The results from these newly developed mouse models indicate a role for MET in hastening tumorigenesis and metastasis when combined with the loss of tumor suppressors.