Identification of tyrosine-phosphorylated proteins associated with metastasis and functional analysis of FER in human hepatocellular carcinoma cells

Abstract

Background-Aberrant activity of tyrosine-phosphorylated proteins is commonly associated with HCC metastasis. Cell signaling events driven by these proteins are implicated in numerous processes that alter cancer cell behavior. Exploring the activities and signaling pathways of these proteins in HCC metastasis may help in identifying new candidate molecules for HCC-targeted therapy.Methods-Hep3B (a nonmetastatic HCC cell line) and MHCC97H (a highly metastatic HCC cell line) were used in this study, and the tyrosine-phosphorylated proteins expressed in these cell lines were profiled by a phosphoproteomics technique based on LC-MS/MS. Protein-protein interaction and functional clustering analyses were performed to determine the activities of the identified proteins and the signaling pathways closely related to HCC metastasis.Results-In both cell lines, a total of 247 phosphotyrosine (pTyr) proteins containing 281 pTyr sites were identified without any stimulation. The involvement of almost 30% of these in liver or liver cancer has not been reported previously. Biological process clustering analysis indicated that pTyr proteins involved in cell motility, migration, protein autophosphorylation, cell-cell communication, and antiapoptosis functions were overexpressed during metastasis. Pathway clustering analysis revealed that signaling pathways such as those involved in EGFR signaling, cytokine- and chemokine-mediated signal transduction, and the PI3K and JAK-STAT cascades were significantly activated during HCC metastasis. Moreover, noncanonical regulation of the JNK cascade might also provide new targets for HCC metastasis. After comparing the pTyr proteins that were differentially expressed during HCC cell metastasis, we selected FER, a nonreceptor tyrosine kinase, and validated its role in terms of both expression and function. The data confirmed that FER might play a critical role in the invasion and metastasis of HCC.Conclusion-The identification of pTyr proteins and signaling pathways associated with HCC metastasis could provide useful information for selecting new molecular intervention targets. Moreover, FER might serve as a novel drug target in future HCC therapy.

FER tyrosine kinase (FER) overexpression mediates resistance to quinacrine through EGF-dependent activation of NF-κB

“…FER is expressed ubiquitously in a variety of tissues and cells (16) and is expressed at a higher level in numerous malignant cell lines than the corresponding normal cells (34)(35)(36). FER expression has been linked to prostate cancer, with higher levels in extracts from cancers compared with normal or hyperplasic tissues (34,35).…”

Fer Protein-Tyrosine Kinase Promotes Lung Adenocarcinoma Cell Invasion and Tumor Metastasis

“…A number of studies have identified Fer activation or upregulation in a number of different cancers, including lung (14), hepatic (15), prostate (16), and triple-negative breast cancer (17). Overexpression of Fer was also linked to quinacrine resistance and enhanced activation of NFkB pathway (5).…”

Oncogenic Properties of a Spermatogenic Meiotic Variant of Fer Kinase Expressed in Somatic Cells

“…At the clinical level, high Fer expression levels have been linked to poor prognosis of hepatocellular carcinoma (HCC; ref. 28), clear cell renal cell carcinoma (29,30), postoperative NSCLC (25), and high-grade basal/triple-negative breast cancer (26).…”