ErbB Receptor Stimulation Is Required for Mouse Colon Adenoma Organoids to Form Crypts
Abstract The majority of colon adenomas harbor genetic mutations in the APC gene. APC mutation leads to changes in Wnt signalling and cell-cell adhesion: as a consequence, intestinal crypt budding increases and the excess crypts accumulate to form adenomas that progress to colon cancer. When cultured with Wnt, R-spondin, EGF, Noggin, myofibroblast conditioned medium and Matrigel, crypts from normal mouse colon mucosa form crypt-producing organoids and can be passaged continuously. Under the same culture and passage conditions, crypts isolated from colon adenomas derived from Apcmin/+ mice typically grow as spheroidal cysts and do not produce crypts. The adenoma organoid growth requires EGF, but not Wnt, R-spondin or Noggin. However, when mouse colon adenoma spheroids are grown for more than 10 days in the presence of EGF, crypt formation occurs. EGF, EREG, β-cellulin, Neuregulin-1 or AREG are sufficient for initiating crypt formation, however, neuregulin-1 is more potent than the other EGF-family members. EGFR and ErbB2 inhibitors both prevent crypt formation in adenoma cultures. Either EGFR:ErbB2 or ErbB3:ErbB2 signalling is sufficient to initiate adenoma crypt budding and elongation. ErbB2 inhibitors may provide a therapeutic avenue for controlling and ablating colon adenomas.
