Lamellipodin-Deficient Mice: A Model of Rectal Carcinoma

• Main Authors: Chen, Xiaowei (Author), Nagar, Karan K. (Author), Wang, Timothy C. (Author), Miller, Cassandra L. (Contributor), Muthupalani, Sureshkumar (Contributor), Shen, Zeli (Contributor), Drees, Frauke (Contributor), Ge, Zhongming (Contributor), Feng, Yan (Contributor), Gong, Guanyu (Contributor), Gertler, Frank (Contributor), Fox, James G (Contributor)
• Other Authors: Massachusetts Institute of Technology. Department of Biological Engineering (Contributor), Massachusetts Institute of Technology. Division of Comparative Medicine (Contributor), Koch Institute for Integrative Cancer Research at MIT (Contributor)
• Format: Article
• Language: English
• Published: Public Library of Science, 2017-05-31T13:20:47Z.
• Subjects: Article
• Online Access: Get fulltext

 During a survey of clinical rectal prolapse (RP) cases in the mouse population at MIT animal research facilities, a high incidence of RP in the lamellipodin knock-out strain, C57BL/6-Raph1[superscript tm1Fbg] (Lpd[superscript -/-]) was documented. Upon further investigation, the Lpd[superscript -/-] colony was found to be infected with multiple endemic enterohepatic Helicobacter species (EHS). Lpd[superscript -/-] mice, a transgenic mouse strain produced at MIT, have not previously shown a distinct immune phenotype and are not highly susceptible to other opportunistic infections. Predominantly male Lpd[superscript -/-] mice with RP exhibited lesions consistent with invasive rectal carcinoma concomitant to clinically evident RP. Multiple inflammatory cytokines, CD11b+Gr1+ myeloid-derived suppressor cell (MDSC) populations, and epithelial cells positive for a DNA damage biomarker, H2AX, were elevated in affected tissue, supporting their role in the neoplastic process. An evaluation of Lpd[superscript -/-] mice with RP compared to EHS-infected, but clinically normal (CN) Lpd[superscript -/-] animals indicated that all of these mice exhibit some degree of lower bowel inflammation; however, mice with prolapses had significantly higher degree of focal lesions at the colo-rectal junction. When Helicobacter spp. infections were eliminated in Lpd[superscript -/-] mice by embryo transfer rederivation, the disease phenotype was abrogated, implicating EHS as a contributing factor in the development of rectal carcinoma. Here we describe lesions in Lpd[superscript -/-] male mice consistent with a focal inflammation-induced neoplastic transformation and propose this strain as a mouse model of rectal carcinoma.