Identification of GATA6 target genes in LS174T colorectal cancer cells using gene expression arrays

ABSTRACT: Aberrant activation of WNT signaling and loss of BMP signals represent the two main alterations leading to the initiation of colorectal cancer (CRC). Here we screen for genes required for maintaining the tumor stem cell phenotype and identify the zinc-finger transcription factor GATA6 as key regulator of the WNT and BMP pathways in CRC. GATA6 directly drives the expression of LGR5 in adenoma stem cells while it restricts BMP signaling to differentiated tumor cells. Genetic deletion of Gata6 in mouse colon adenomas increases the levels of BMP factors, which signal to block self-renewal of tumor stem cells. In human tumors, GATA6 competes with beta-catenin/TCF4 for binding to a distal regulatory region of the BMP4 locus that has been previously linked to increased susceptibility to develop CRC. Hence, GATA6 creates a permissive environment for tumor stem cell expansion by controlling the major signaling pathways that influence CRC initiation. Total RNA was collected from biological replicates of LS174T colorectal cancer cells transduced with either short hairpin against GATA6 (shGATA6) or non-silencing control (NS) grown in DMEM supplemented with 10% FBS in the presence of doxycycline (dox: 1 µg mL-1; Sigma Aldrich) or vehicle (70% ethanol) for a period of 72h. Short hairpins were designed and cloned into doxycycline inducible pTRIPZ lentiviral vector (Open Biosystems). Additionally a 4-hydoxy tamoxifen inducible system was used to inducibly block beta-catenin/TCF activity for a period of 36h. Briefly, the ERT2 domain from the pCMV-CRE-ERT2 (Feil et al., 1996) was amplified by PCR and cloned into a modified FUGW lentiviral vector backbone (Lois et al., 2002). NTCF was then amplified byPCR from the pCDNA3.1-NTCF-NLS (van de Wetering et al., 2002) and cloned in frame upstream of the ERT2 from the FUW-CMV-ERT2 (ET) to create the FUW-CMV-NTCF-ERT2 (NET). Total RNA was extracted using the TRIzol® Plus RNA Purification Kit (Life Technologies).

ORGANISM(S): Homo sapiens

SUBMITTER: Camille Stephan-Otto Attolini 

PROVIDER: E-GEOD-56895 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress