Promoter identification and transcriptional regulation of the metastasis gene MACC1 in colorectal cancer

Abstract

MACC1, Metastasis associated in colon cancer 1, is a newly identified prognostic biomarker for colorectal cancer metastasis and patient survival, when determined in the primary tumor or patient blood. MACC1 induces cell motility and proliferation in cell culture and metastasis in mouse models. MACC1 acts as a transcriptional regulator of the receptor tyrosine kinase gene Met via binding to its promoter. However, no information about the promoter of the MACC1 gene and its transcriptional regulation has been reported so far. Here we report the identification of the MACC1 promoter using a promoter luciferase construct that directs transcription of MACC1. To gain insights into the essential domains within this promoter region, we constructed 5' truncated deletion constructs. Our results show that the region from -426 to -18 constitutes the core promoter and harbors functional motifs for the binding of AP-1, Sp1, and C/EBP transcription factors as validated by site directed mutagenesis study. Using electrophoretic mobility shift assay and chromatin immunoprecipitation assay, we demonstrated the physical interaction of these transcription factors to a minimal essential MACC1 core promoter sequence. Knock down of these transcription factors using RNAi strategy reduced MACC1 expression (P < 0.001), and resulted in decrease of cell migration (P < 0.01) which could be specifically rescued by ectopic overexpression of MACC1. In human colorectal tumors, expression levels of c-Jun and Sp1 correlated significantly to MACC1 (P = 0.0007 and P = 0.02, respectively). Importantly, levels of c-Jun and Sp1 also showed significant correlation to development of metachronous metastases (P = 0.01 and P = 0.001, respectively). This is the first study identifying the MACC1 promoter and its transcriptional regulation by AP-1 and Sp1. Knowledge of the transcriptional regulation of the MACC1 gene will implicate in enhanced understanding of its role in cancer progression and metastasis.

Statin and rottlerin small-molecule inhibitors restrict colon cancer progression and metastasis via MACC1

“…Therefore, we wanted to know if lovastatin influences c-Jun and Sp1 binding to the human MACC1 promoter. This was investigated by electrophoretic mobility shift assay (EMSA), using biotinylated oligonucleotides encompassing the c-Jun or Sp1 binding site of the MACC1 promoter as described earlier [27]. In solvent-treated HCT116 cells, a strong signal was observed because of the binding of c-Jun and Sp1 with their respective biotinylated oligonucleotides, consistent with our previous findings.…”

MACC1 expression levels as a novel prognostic marker for colorectal cancer

“…The present study is considered to be important as it has provided analyses of a large number of samples, which demonstrate that MACC1 expression levels may be used as a statistically significant marker for CRC metastasis following curative resection, along with other reported predictors ( 13 ). The present results support recent reports that a MACC1 -dependent signaling pathway is involved in the progression of CRC ( 12 , 14 , 15 ).…”

Identification of chicken FSHR gene promoter and the correlations between polymorphisms and egg production in Chinese native hens

“…Gene promoters play a key role in transcriptional regulation by controlling the transcription initiation site, time and expression level (Juneja, Ilm, Schlag, & Stein, ). Therefore, research on the regulation of gene expression can start from the structural function of its promoter.…”