NFAT transcriptional activity is associated with metastatic capacity in colon cancer

Colorectal carcinoma is the third leading cause of cancer-related death in the United States. In order to understand the mechanism/signaling pathways responsible for invasion, migration and metastasis in colorectal cancer, we developed an integrative and comparative genetic approach to infer transcriptional regulatory mechanisms underlying colon cancer progression. Accordingly, we filtered fourteen human colorectal cancer (CRC) microarray data sets, from an immune competent mouse model of metastasis to identify known and novel transcriptional regulators in CRC. Using this approach, Nuclear Factor of Activated T cells (NFAT) family of transcription factors were identified as metastasis driver of colon cancer. NFAT family of transcription factors is known to induce gene transcription in various disease processes, including carcinogenesis. We used parental and metastatic derivatives of MC38 mouse colon cancer cells (MC38Par and MC38Met, respectively) to evaluate the role of NFATc1 in cancer cell invasiveness. We found that high NFATc1 expression correlates with significantly increased (p<0.0001) Trans-Endothelial Invasion (TEI) in MC38Met cells. Conversely, RNAi-based inhibition of NFATc1 expression and functional inhibition with calcineurin inhibitor FK506 in MC38Met cells, both resulted in significant decreased TEI (p=0.0193 & p=0.0003). Furthermore, a set of predicted NFATc1 target mRNAs identified in our original analysis were downregulated by knock-down of NFATc1 or functional inhibition with FK506 in MC38Met cells. The expression level (mRNA) of predicted gene targets were high in human CRC specimens which had higher than median NFATc1 mRNA expression (n=11 out of total 22). The tumor-associated NFATc1 co-regulated gene signature is significantly correlated with both disease-specific and disease-free survival in Stage II and III CRC patients. We have successfully demonstrated a bioinformatics approach to identify a tumor promoter driver gene NFATc1. Our studies suggest a role of NFATc1 towards invasion and its co-regulated gene signature for poor outcomes in colorectal cancer.

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Tripathi MK, Deane NG, Zhu J, An H, Mima S, Wang X, Padmanabhan S, Shi Z, Prodduturi N, Ciombor KK, Chen X, Washington MK, Zhang B, Beauchamp RD