Chian-Feng Chen

Overlapping high-resolution copy number alterations in cancer genomes identified putative cancer genes in hepatocellular carcinoma.

Recurrent cancer genome aberrations are indicators of residing crucial cancer genes. Although recent advances in genomic technologies have led to a global view of cancer genome aberrations, the identification of target genes and biomarkers from the aberrant loci remains difficult. To facilitate searches of cancer genes in human hepatocellular carcinoma (HCC), we established a comprehensive protocol to analyze copy number alterations (CNAs) in cancer genomes using high‐density single nucleotide polymorphism arrays with unpaired reference genomes. We identified common HCC genes by overlapping the shared aberrant loci in multiple cell lines with functional validation and clinical implications. A total of 653 amplicons and 57 homozygous deletions (HDs) were revealed in 23 cell lines. To search for novel HCC genes, we overlapped aberrant loci to uncover 6 HDs and 126 amplicons shared by at least two cell lines. We selected two novel genes, fibronectin type III domain containing 3B (FNDC3B) at the 3q26.3 overlapped amplicon and solute carrier family 29 member 2 (SLC29A2) at the 11q13.2 overlapped amplicon, to investigate their aberrations in HCC tumorigenesis. Aberrant up‐regulation of FNDC3B and SLC29A2 occurred in multiple HCC data sets. Knockdown of these genes in amplified cells decreased cell proliferation, anchorage‐independent growth, and tumor formation in xenograft models. Importantly, up‐regulation of SLC29A2 in HCC tissues was significantly associated with advanced stages (P = 0.0031), vascular invasion (P = 0.0353), and poor patient survival (P = 0.0325). Overexpression of FNDC3B or SLC29A2 in unamplified HCC cells promoted cell proliferation through activation of the signal transducer and activator of transcription 3 signaling pathway. Conclusion: A standardized genome‐wide CNA analysis protocol using data from user‐generated or public domains normalized with unpaired reference genomes has been established to facilitate high‐throughput detection of cancer genes as significant target genes and biomarkers for cancer diagnosis and therapy. (HEPATOLOGY 2010)

IGDB.NSCLC: integrated genomic database of non-small cell lung cancer

Lung cancer is the most common cause of cancer-related mortality with more than 1.4 million deaths per year worldwide. To search for significant somatic alterations in lung cancer, we analyzed, integrated and manually curated various data sets and literatures to present an integrated genomic database of non-small cell lung cancer (IGDB.NSCLC, http://igdb.nsclc.ibms.sinica.edu.tw). We collected data sets derived from hundreds of human NSCLC (lung adenocarcinomas and/or squamous cell carcinomas) to illustrate genomic alterations [chromosomal regions with copy number alterations (CNAs), gain/loss and loss of heterozygosity], aberrant expressed genes and microRNAs, somatic mutations and experimental evidence and clinical information of alterations retrieved from literatures. IGDB.NSCLC provides user friendly interfaces and searching functions to display multiple layers of evidence especially emphasizing on concordant alterations of CNAs with co-localized altered gene expression, aberrant microRNAs expression, somatic mutations or genes with associated clinicopathological features. These significant concordant alterations in NSCLC are graphically or tabularly presented to facilitate and prioritize as the putative cancer targets for pathological and mechanistic studies of lung tumorigenesis and for developing new strategies in clinical interventions.

Association study of genetic polymorphisms of SLC2A10 gene and type 2 diabetes in the Taiwanese population

Aims/hypothesisThe gene encoding solute carrier family 2, facilitated glucose transporter, member 10 (SLC2A10, previously known as glucose transporter 10 [GLUT10]) is a promising candidate gene for type 2 diabetes since it is highly expressed in liver and pancreas and is located on human chromosome region 20q12–q13.1, a region previously shown to harbour type 2 diabetes susceptibility genes. We investigated whether the SLC2A10 gene could be a type 2 diabetes susceptibility gene in the Taiwanese population.Subjects and methodsSequencing of SLC2A10 gene from 48 diabetic subjects detected short tandem repeat polymorphisms in the promoter region, but did not detect any other sequence variants or new single-nucleotide polymorphisms (SNPs) other than those already in the SNPper database (http://snpper.chip.org) (30 June 2005).ResultsUsing these genetic polymorphisms, we divided the SLC2A10 gene into four distinct linkage disequilibrium blocks and performed a case-control association study in a group of type 2 diabetes subjects (n=375) and normoglycaemic individuals (n=377). The HapD (A-G-T-C) haplotype in block 3, a rare haplotype, which consisted of four SNPs (rs3092412, rs2235491, rs2425904 and rs1059217), was modestly associated with type 2 diabetes with a haplotype score of −2.95567 (p=0.012 with the haplotype-specific test).Conclusions/interpretationOur results suggest that SLC2A10 genetic variations do not appear to be major determinants for type 2 diabetes susceptibility in the Taiwanese population.

Overexpressed-eIF3I interacted and activated oncogenic Akt1 is a theranostic target in human hepatocellular carcinoma.

Eukaryotic translation initiation factor 3 subunit I (eIF3I) with transforming capability is often overexpressed in human hepatocellular carcinoma (HCC) but its oncogenic mechanisms remain unknown. We demonstrate that eIF3I is overexpressed in various cancers along with activated Akt1 phosphorylation and kinase activity in an eIF3I dose‐dependent manner. A novel eIF3I and Akt1 protein interaction was identified in HCC cell lines and tissues and was required for eIF3I‐mediated activation of Akt1 signaling. Expression of either antisense eIF3I or dominant negative Akt1 mutant suppressed eIF3I‐mediated Akt1 oncogenic signaling and various other tumorigenic effects. Oncogenic domain mapping of the eIF3I and Akt1 interaction suggested that the C‐terminal eIF3I interacted with the Akt1 kinase domain and conferred the majority of oncogenic functions. In addition, eIF3I interaction with Akt1 prevented PP2A dephosphorylation of Akt1 and resulted in constitutively active Akt1 oncogenic signaling. Importantly, concordant expression of endogenous eIF3I and phospho‐Akt1 was detected in HCC cell lines and tissues. Treatment of eIF3I overexpressing HCC cells with the Akt1 specific inhibitor API‐2 suppressed eIF3I‐mediated tumorigenesis in vitro and in vivo. Conclusion: We describe a constitutive Akt1 oncogenic mechanism resulting from interaction of overexpressed eIF3I with Akt1 that prevents PP2A‐mediated dephosphorylation. Overexpression of eIF3I in HCC is oncogenic and is a surrogate marker and therapeutic target for treatment with Akt1 inhibitors. (HEPATOLOGY 2013;)

Target genes discovery through copy number alteration analysis in human hepatocellular carcinoma

High-throughput short-read sequencing of exomes and whole cancer genomes in multiple human hepatocellular carcinoma (HCC) cohorts confirmed previously identified frequently mutated somatic genes, such as TP53, CTNNB1 and AXIN1, and identified several novel genes with moderate mutation frequencies, including ARID1A, ARID2, MLL, MLL2, MLL3, MLL4, IRF2, ATM, CDKN2A, FGF19, PIK3CA, RPS6KA3, JAK1, KEAP1, NFE2L2, C16orf62, LEPR, RAC2, and IL6ST. Functional classification of these mutated genes suggested that alterations in pathways participating in chromatin remodeling, Wnt/β-catenin signaling, JAK/STAT signaling, and oxidative stress play critical roles in HCC tumorigenesis. Nevertheless, because there are few druggable genes used in HCC therapy, the identification of new therapeutic targets through integrated genomic approaches remains an important task. Because a large amount of HCC genomic data genotyped by high density single nucleotide polymorphism arrays is deposited in the public domain, copy number alteration (CNA) analyses of these arrays is a cost-effective way to reveal target genes through profiling of recurrent and overlapping amplicons, homozygous deletions and potentially unbalanced chromosomal translocations accumulated during HCC progression. Moreover, integration of CNAs with other high-throughput genomic data, such as aberrantly coding transcriptomes and non-coding gene expression in human HCC tissues and rodent HCC models, provides lines of evidence that can be used to facilitate the identification of novel HCC target genes with the potential of improving the survival of HCC patients.

IGRhCellID: integrated genomic resources of human cell lines for identification

Cell line identification is emerging as an essential method for every cell line user in research community to avoid using misidentified cell lines for experiments and publications. IGRhCellID (http://igrcid.ibms.sinica.edu.tw) is designed to integrate eight cell identification methods including seven methods (STR profile, gender, immunotypes, karyotype, isoenzyme profile, TP53 mutation and mutations of cancer genes) available in various public databases and our method of profiling genome alterations of human cell lines. With data validation of 11 small deleted genes in human cancer cell lines, profiles of genomic alterations further allow users to search for human cell lines with deleted gene to serve as indigenous knock-out cell model (such as SMAD4 in gene view), with amplified gene to be the cell models for testing therapeutic efficacy (such as ERBB2 in gene view) and with overlapped aberrant chromosomal loci for revealing common cancer genes (such as 9p21.3 homozygous deletion with co-deleted CDKN2A, CDKN2B and MTAP in chromosome view). IGRhCellID provides not only available methods for cell identification to help eradicating concerns of using misidentified cells but also designated genetic features of human cell lines for experiments.

FNDC3B promotes cell migration and tumor metastasis in hepatocellular carcinoma

Recurrence and metastasis are common in hepatocellular carcinoma (HCC) and correlate with poor prognosis. We investigated the role of fibronectin type III domain containing 3B (FNDC3B) in HCC metastasis. Overexpression of FNDC3B in HCC cell lines enhanced cell migration and invasion. On the other hand, knockdown of FNDC3B using short-hairpin RNA reduced tumor nodule formation in both intra- and extra-hepatic metastasis. High levels of FNDC3B were observed in metastatic HCCs and correlated with poor patient survival and shorter recurrence time. Mutagenesis and LC-MS/MS analyses showed that FNDC3B promotes cell migration by cooperating with annexin A2 (ANXA2). Furthermore, FNDC3B and ANXA2 expression correlated negatively with patient survival. Our results indicate that FNDC3B behaves like an oncogene by promoting cell migration. This suggests FNDC3B could serve as a biomarker and therapeutic target for HCC metastasis.

Loss of PTPRM Associates with the Pathogenic Development of Colorectal Adenoma-Carcinoma Sequence

Identification and functional analysis of genes from genetically altered chromosomal regions would suggest new molecular targets for cancer diagnosis and treatment. Here we performed a genome-wide analysis of chromosomal copy number alterations (CNAs) in matching sets of colon mucosa-adenoma-carcinoma samples using high-throughput oligonucleotide microarray analysis. In silico analysis of NCBI GEO and TCGA datasets allowed us to uncover the significantly altered genes (p ≤ 0.001) associated with the identified CNAs. We performed quantitative PCR analysis of the genomic and complementary DNA derived from primary mucosa, adenoma, and carcinoma samples, and confirmed the recurrent loss and down-regulation of PTPRM in colon adenomas and carcinomas. Functional characterization demonstrated that PTPRM negatively regulates cell growth and colony formation, whereas loss of PTPRM promotes oncogenic cell growth. We further showed that, in accordance to Knudsons two-hit hypothesis, inactivation of PTPRM in colon cancer was mainly attributed to loss of heterozygosity and promoter hypermethylation. Taken together, this study demonstrates a putative tumor suppressive role for PTPRM and that genetic and epigenetic alterations of PTPRM may contribute to early step of colorectal tumorigenesis.

PSPC1 mediates TGF-β1 autocrine signalling and Smad2/3 target switching to promote EMT, stemness and metastasis

Activation of metastatic reprogramming is critical for tumour metastasis. However, more detailed knowledge of the underlying mechanism is needed to enable targeted intervention. Here, we show that paraspeckle component 1 (PSPC1), identified in an aberrant 13q12.11 locus, is upregulated and associated with poor survival in patients with cancer. PSPC1 promotes tumorigenesis, epithelial-to-mesenchymal transition (EMT), stemness and metastasis in multiple cell types and in spontaneous mouse cancer models. PSPC1 is the master activator for transcription factors of EMT and stemness and accompanies c-Myc activation to facilitate tumour growth. PSPC1 increases transforming growth factor-β1 (TGF-β1) secretion through an interaction with phosphorylated and nuclear Smad2/3 to potentiate TGF-β1 autocrine signalling. Moreover, PSPC1 acts as a contextual determinant of the TGF-β1 pro-metastatic switch to alter Smad2/3 binding preference from tumour-suppressor to pro-metastatic genes. Having validated the PSPC1–Smads–TGF-β1 axis in various cancers, we conclude that PSPC1 is a master activator of pro-metastatic switches and a potential target for anti-metastasis drugs.Yeh et al. find that PSPC1 is upregulated in cancer and interacts with Smad2/3 to induce TGF-β1. This leads to increased autocrine TGF-β1 signalling and a switch to pro-metastatic TGF-β1-dependent gene expression.