MUC1-C drives stemness in progression of colitis to colorectal cancer
Wei Li, … , Song Liu, Donald Kufe
Wei Li, … , Song Liu, Donald Kufe
Published May 19, 2020
Citation Information: JCI Insight. 2020;5(12):e137112. https://doi.org/10.1172/jci.insight.137112.
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Research Article Oncology Therapeutics

MUC1-C drives stemness in progression of colitis to colorectal cancer

Abstract

Colitis is associated with the development of colorectal cancer (CRC) by largely undefined mechanisms that are critical for understanding the link between inflammation and cancer. Intestinal stem cells (ISCs) marked by leucine-rich repeat–containing G protein–coupled receptor 5 (LGR5) expression are of importance in both the inflammatory response to colitis and progression to colitis-associated colon cancer (CACC). Here, we report in human mucin 1–transgenic (MUC1-transgenic) mouse models of CACC, targeting the MUC1-C oncogenic protein suppresses the (a) Lgr5+ ISC population, (b) induction of Myc and core pluripotency stem cell factors, and (c) severity and progression of colitis to dysplasia and cancer. By extension to human colon cancer cells, we demonstrate that MUC1-C drives MYC, forms a complex with MYC on the LGR5 promoter, and activates LGR5 expression. We also show in CRC cells that MUC1-C induces cancer stem cell (CSC) markers (BMI1, ALDH1, FOXA1, LIN28B) and the OCT4, SOX2, and NANOG pluripotency factors. Consistent with conferring the CSC state, targeting MUC1-C suppresses the capacity of CRC cells to promote wound healing, invasion, self-renewal, and tumorigenicity. In analysis of human tissues, MUC1 expression associates with activation of inflammatory pathways, development of colitis, and aggressiveness of CRCs. These results collectively indicate that MUC1-C is of importance for integrating stemness and pluripotency in colitis and CRC. Of clinical relevance, the findings further indicate that MUC1-C represents a potentially previously unrecognized target that is druggable for treating progression of colitis and CRC.

Authors

Wei Li, Ning Zhang, Caining Jin, Mark D. Long, Hasan Rajabi, Yota Yasumizu, Atsushi Fushimi, Nami Yamashita, Masayuki Hagiwara, Rongbin Zheng, Jin Wang, Ling Kui, Harpal Singh, Surender Kharbanda, Qiang Hu, Song Liu, Donald Kufe

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Figure 6

MUC1-C/MYC signaling induces LGR5 and BMI1 expression.

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MUC1-C/MYC signaling induces LGR5 and BMI1 expression. (A) Amino acid se...
(A) Amino acid sequence of the MUC1-C cytoplasmic domain with the SAGNGGSSLS motif that binds directly to β-catenin (44). The MUC1-C CQC motif binds directly to the TCF4 E-tail C-clamp region (45). MUC1-C thereby forms a ternary complex with β-catenin and TCF4 on WNT target genes, such as CCND1 and MYC, to activate their transcription (45, 46). The MUC1-C CQC motif is targeted by the GO-203 inhibitor, which disrupts the interaction with TCF4 and thereby activation of the WNT pathway (45, 46). RNA-Seq was performed in triplicate on SW620 MUC1shRNA cells treated with vehicle or 500 ng/mL DOX for 7 days. Silencing MUC1-C expression was significantly associated with suppression of the indicated HALLMARK gene set. (B) SW620 tet-CshRNA and SW620 tet-MUC1shRNA cells were treated with vehicle or 500 ng/mL DOX for 7 days. (C) Nuclear lysates from SW620 cells were precipitated with anti–MUC1-C and an IgG control antibody. Input proteins and the precipitates were immunoblotted with antibodies against MUC1-C and MYC. (D) SW620 cells expressing a tet-MYCshRNA were treated with vehicle or 500 ng/mL DOX for 7 days. (E) Schema of the LGR5 promoter region. Soluble chromatin from SW620 cells was precipitated with a control IgG, anti–MUC1-C, or anti-MYC (left). Soluble chromatin was precipitated with anti–MUC1-C (ChIP) and then reprecipitated with anti-MYC or a control IgG (re-ChIP) (right). (F) Soluble chromatin from SW620 tet-CshRNA and SW620 tet-MUC1shRNA cells treated with 500 ng/mL DOX for 7 days was precipitated with anti-MYC or a control IgG. The DNA samples were amplified by quantitative PCR (qPCR) with primers for the LGR5 promoter. (G) Schema of the BMI1 promoter region (9). Soluble chromatin from SW620 cells was precipitated with a control IgG, anti-MUC1-C or anti-MYC (left). Soluble chromatin was precipitated with anti-MUC1-C (ChIP) and then reprecipitated with anti-MYC or a control IgG (re-ChIP) (right). (H) Soluble chromatin from SW620 tet-CshRNA and SW620 tet-MUC1shRNA cells treated with 500 ng/mL DOX for 7 days was precipitated with anti-MYC or a control IgG. The DNA samples were amplified by qPCR with primers for the BMI1 promoter. The results (mean ± SD of 3 determinations) are expressed as the relative fold enrichment compared with that obtained with the IgG control (assigned a value of 1).