hTERT may promote CRC by recruiting β-catenin/TCF-4 complex to transactivate CCL2 expression, which is a novel crosstalk mechanism likely involved in the pathogenesis of CRC.
In the present study, we investigated whether CRNDE was involved in the development of colorectal cancer via the binding of microRNA (miR)-217 with transcription factor 7-like 2 (TCF7L2) to enhance the Wnt signaling pathway.
The results indicated that the TCF7L2rs11196172 polymorphism increases the risk of CRC independently, with no evidence of an interaction with diabetes or obesity.
To better characterize the causal relationship between β-catenin and MUCDHL expression, we performed various experiments in which CRC cell lines and normal colonic organoids were subjected to culture conditions inhibiting (FH535 treatment, transcription factor 7-like 2 siRNA inactivation, Wnt withdrawal) or stimulating (LiCl treatment) β-catenin activity.
The results demonstrate that patients with the T/T genotype for the rs12255372 polymorphism of the TCF7L2 gene present an increased colorectal cancer risk (OR=2.64, P=0.0236).
T-cell factor-4 (TCF4) is a member of the TCF/LEF (lymphoid enhancer factor) family of transcription factors, and dysregulation of β-catenin is decisive for the initiation and progression of colorectal cancer.
The intestine-specific transcription factor CDX2 and Wnt effector TCF7L2 bound near rs16969681, with significantly higher affinity for the risk allele, and CDX2 overexpression in CDX2/GREM1-negative cells caused re-expression of GREM1. rs16969681 influences CRC risk through effects on Wnt-driven GREM1 expression in colorectal tumors.
In conclusion, we have identified novel variants of VTI1A-TCF7L2 fusion transcripts, including a novel fusion partner gene, RP11-57H14.3, and demonstrated detectable levels in a large fraction of CRC samples, as well as in normal colonic mucosa and other tissue types.
The single nucleotide polymorphism (SNP) rs6983267 on chromosome 8q24 is a CRC susceptibility locus that affects binding activity of transcription factor 7 like-2 (TCF7L2) to CTNNB1, thereby altering expression of target oncogenes, including MYC.
The results showed that TCF7L2 polymorphism was associated with breast cancer (Homogeneous model: OR=1.17, 95%CI=1.02-1.35, I (2) =21.8%, p for heterogeneity=0.276; Heterogeneous model: OR=1.11, 95%CI=1.03-1.20, I (2) =0.0%, p for heterogeneity=0.543), prostate cancer (Homogeneous model: OR=0.89, 95%CI=0.84-0.96, I (2) =0.0%, p for heterogeneity=0.640; Heterogeneous model: OR=0.89, 95%CI=0.84-0.95, I (2) =0.0%, p for heterogeneity=0.871), and colon cancer (Heterogeneous model: OR=1.15, 95%CI=1.01-1.31, I (2) =0.0%, p for heterogeneity=0.658), but not with colorectal cancer, lung cancer, and ovarian cancer.
A further analysis revealed gender-specific effects: the TCF7L2_rs7903146_T allele was associated with an increased risk of CRC in women (P(trend) = 0.003) but not in men (P(interaction) = 0.06); the LTA_rs1041981_A allele was associated with a decreased risk for CRC in women (P(trend) = 0.02), with an opposite effect in men (P(trend) = 0.05; P(interaction) = 0.002); the CDKAL1_rs7754840_C allele was associated with a decreased risk for CRC in men (P(trend) = 0.03), with no effect in women (P(interaction) = 0.03).