Priority Research Paper Volume 14, Issue 5 pp 2025—2046

Depletion of transmembrane mucin 4 (Muc4) alters intestinal homeostasis in a genetically engineered mouse model of colorectal cancer

Ramesh Pothuraju1, , Priya Pai1, *, , Sanjib Chaudhary1, *, , Jawed A. Siddiqui1, , Jesse L. Cox2, , Sukhwinder Kaur1, , Satyanarayana Rachagani1, , Hemant K. Roy3, , Michael Bouvet4,5, , Surinder K. Batra1,6,7, ,

  • 1 Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE 68198, USA
  • 2 Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE 68198, USA
  • 3 Department of Medicine, Baylor College of Medicine, Houston, TX 77030, USA
  • 4 Division of Surgical Oncology, Department of Surgery, University of California San Diego, La Jolla, CA 92093, USA
  • 5 VA San Diego Healthcare System, San Diego, CA 92161, USA
  • 6 Fred and Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, NE 68198, USA
  • 7 Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE 68198, USA
* Equal contribution

Received: November 4, 2021       Accepted: February 21, 2022       Published: March 7, 2022
How to Cite

Copyright: © 2022 Pothuraju et al. This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.


Mucins are components of the mucus layer overlying the intestinal epithelial cells, which maintains physiological homeostasis. Altered mucin expression is associated with disease progression. Expression of MUC4 decreases in colorectal cancer (CRC); however, its functional role and implications in the intestinal pathology in CRC are not studied well. Therefore, we generated a genetically engineered Muc4 knockout (Muc4-/-) CRC mouse model by crossing with Muc4-/- and Apcflox/flox mice in the presence of colon-specific inducible Cre. We observed that deficiency of Muc4 results in an increased number of macroscopic tumors in the colon and rectal region and leads to poor survival. Further, the absence of Muc4 was associated with goblet cell dysfunction where the expression of intestinal homeostasis molecules (Muc2 and Fam3D) was downregulated. Next, we also observed that loss of Muc4 showed reduced thickness of mucus layer, leading to infiltration of bacteria, reduction in anti-microbial peptides, and upregulation of pro-inflammatory cytokines. Further, Apc gene mutation results in activation of the Wnt/β-catenin signaling pathway that corroborated with an increased nuclear accumulation of β-catenin and activation of its target genes: cyclin D1 and c-Myc in Muc4-/- mice was observed. We conclude that the presence of Muc4 is essential for intestinal homeostasis, reduces tumor burden, and improves overall survival.


CRC: Colorectal cancer; MUC4: mucin 4; APC: adenomatous polyposis coli; GEM: genetically engineered mouse; Cdx-2: caudal type homeobox transcription factor 2; MUC2: mucin 2; DAPI: 4′,6-diamidino-2-phenylindole; FBS: fetal bovine serum; KD: knockdown; PBS: phosphate buffered saline; PAS: Periodic acid-Schiff; FISH: Fluorescence in situ hybridization; HEPES: 4-(2-hydroxyethyl)-1-piperazine-ethanesulfonic acid; KCl: potassium chloride; EDTA: Ethylenediaminetetraacetic acid; MgCl2: Magnesium chloride; DTT: Dithiothreitol; PMSF: Phenylmethanesulfonyl fluoride; Na3VO4: Sodium orthovanadate; NaF: Sodium fluoride: RIPA: Radioimmunoprecipitation assay buffer: TCGA: The Cancer Genome Atlas; KD: Knockdown; PCR: Polymerase Chain Reaction; AC: Apc-/-;Cdx2P-creERT2; AMC: Apc-/-;Muc4-/-;Cdx2P-creERT2; AKC: Apc-/-;KrasG12D/+;Cdx2P-creERT2; AKMC: Apc-/-;KrasG12D/+;Muc4-/-;Cdx2P-creERT2.