Table 3 Biological functions of the 10 most up- and down-regulated genes

APCDD1

• Directly regulated by the β-catenin/T-cell factor signaling complex

• Increased expression in colon cancer cells and potential roles in colorectal tumorigenesis [75].

TWIST2

• A basic helix-loop-helix transcription factor

• Inhibits both p21WAF1/Cip1 (cyclin dependent kinase inhibitor) and muscle creatinine kinase (MCK)

• Functional association with cellular growth arrest and myogenesis specific expression [76]

• Possibly alternate regulatory factor involved in the lowered expression of p21WAF1/Cip1 in DF-1 cells that in turn would support the faster growth rate that is characteristic of the DF-1 cell line [19].

TMEM116

• Unknown functions

• A single nucleotide polymorphisms are associated with insulin-dependent diabetes mellitus in human [77]

MYH6

• Alpha subunit of cardiac muscle myosin

• Association cytoskeletal or muscle architecture [78]

• Taken together with MYL10 (myosin light chain 10), which is up-regulated in DF-1 cells (Additional file 2), mutations are associated with cardiomyopathy or cardiac hypertrophy [79]

CARD11

• Known as Carma1 belonging to the membrane-associated guanylate kinase (MAGUK) family that is essential in antigen receptor-induced nuclear factor κB (NF- κB) activity in T-cell activation [80]

PLEK2

• A membrane associated protein containing PH (pleckstrin homology) motifs that bind polyphosphoinositides

• Roles in orchestrating cytoskeletal structural arrangement [81]

OSGIN1

• Known as BDGI [BMSC (bone marrow stromal cell)- derived growth inhibitor] or OKL38 (pregnancy-induced growth inhibitor)

• Suppression of the growth of MCF7 human breast cancer cell by inducing cell cycle arrest and apoptosis when OSGIN1 was ectopically expressed exogenously [82]

COLEC10

• Known as CLL1 (colletin liver 1), a member of the C-lectin family

• Roles in initial host defense by binding sugars on the cell surface of microorganisms through their carbohydrate recognition domain [83].

• Essential host factor for early replication of influenza virus in cultured cells revealed by genome wide siRNA screening [84]

• Its mRNA down-regulated in human liver hepatocellular carcinoma by microarray analysis [85].

SOCS1

• Suppression of many cytokine-signaling pathways by inhibiting JAK tyrosine kinase activity and functions as antioncogene by antagonizing tumor cell growth [86].

VPS13B

• Known as COH1, involved in intracellular vesicle-mediated sorting and transport of proteins and with Cohen syndrome, which is an autosomal recessive disorder in human caused by the genetic mutation in COH1 gene [87].

Down-regulation

Symbol

Functions

NOV

• Known as CCN3, a member of the secreting insulin like growth factor binding protein family with antiprolifereative effects on tumor cells [88, 89].

SLC25A4

• Known as ANT1 (adenine nucleotide translocator 1)

• Localized to the inner mitochondrial membrane, exchanges cytosolic ADP for mitochondrial ATP, and induces apoptosis by the mitochondrial recruitment of NF-κB [90].

• Decrease in ANT1 might play in a role in immortalization characteristics by suppressing the induction of apoptosis in DF-1 cells.

CDKN2B

• Known as p15INK4B, CDK4/6 inhibitor

• Arrest cell cycle and induce cellular senescence [91].

• The down-regulation in DF-1 cells caused by hyper-methylation

• Functional roles both in the progression of cellular senescence and in brain development were reported previously [92, 93].

ST3GAL1

• Type II membrane protein that catalyzes the transfer of sialic acid from CMP-sialic acid to galactose-containing substrates

• A knock-out mutation increases apoptosis of mouse T lymphocytes expressing the CD8 complex, indicating a homeostatic function of STGAL1 in T lymphocyte [94].

PTGS2

• Known as COX2 (cyclooxygenase 2), the key rate-limiting enzyme in prostaglandin biosynthesis with both dioxygenase and peroxidase activity

• Inhibition of apoptosis by suppressing caspase pathways and the increase of survival mechanisms through Akt activation [95].

CTHRC1

• A secreted protein in injured and diseases arteries that inhibits collagen expression and promotes cell migration [96].

EPHA3

• A unique member of the receptor tyrosine kinase family

• Roles in regulating cell shape and cell movement [97].

MANSC1

• A protein containing a MANSC (motif at N terminus with seven cysteines) domain that presents certain membrane- and extracellular proteins such as LPR11 (low-density lipoprotein receptor-related protein 11) and HAI1 (hepatocyte growth factor activator inhibitor 1) [98]

• Unknown the functions

CCK

• A gastrointestinal and neuronal peptide with important regulatory roles in the digestive tract and nervous system, including both acute and more chronic trophic effects

• Binding its receptor triggers the activation of multiple signal transduction pathways that relay the mitogenic signal to the nucleus and promote cell proliferation [99].

MAB21L1

• A knock-out mutation led to the defects in eye and perputial gland formation [100]