title: Plecanatide-mediated activation of guanylate cyclase-C suppresses inflammation-induced colorectal carcinogenesis in Apc+/Min-FCCCmice.
abstract: OBJECTIVE
  To evaluate the effect of orally administered plecanatide on colorectal dysplasia in Apc+/Min-FCCCmice with dextran sodium sulfate (DSS)-induced inflammation.
  
  
  METHODS
  Inflammation driven colorectal carcinogenesis was induced in Apc+/Min-FCCCmice by administering DSS in their drinking water. Mice were fed a diet supplemented with plecanatide (0-20 ppm) and its effect on the multiplicity of histopathologically confirmed polypoid, flat and indeterminate dysplasia was evaluated. Plecanatide-mediated activation of guanylate cyclase-C (GC-C) signaling was assessed in colon tissues by measuring cyclic guanosine monophosphate (cGMP) by ELISA, protein kinase G-II and vasodilator stimulated phosphoprotein by immunoblotting. Ki-67, c-myc and cyclin D1 were used as markers of proliferation. Cellular levels and localization of β-catenin in colon tissues were assessed by immunoblotting and immunohistochemistry, respectively. Uroguanylin (UG) and GC-C transcript levels were measured by quantitative reverse transcription polymerase chain reaction (RT-PCR). A mouse cytokine array panel was used to detect cytokines in the supernatant of colon explant cultures.
  
  
  RESULTS
  Oral treatment of Apc+/MinFCCCmice with plecanatide produced a statistically significant reduction in the formation of inflammation-driven polypoid, flat and indeterminate dysplasias. This anti-carcinogenic activity of plecanatide was accompanied by activation of cGMP/GC-C signaling mediated inhibition of Wnt/β-catenin signaling and reduced proliferation. Plecanatide also decreased secretion of pro-inflammatory cytokines (IL-6, IL1 TNF), chemokines (MIP-1, IP-10) and growth factors (GCSF and GMCSF) from colon explants derived from mice with acute DSS-induced inflammation. The effect of plecanatide-mediated inhibition of inflammation/dysplasia on endogenous expression of UG and GC-C transcripts was measured in intestinal tissues. Although GC-C expression was not altered appreciably, a statistically significant increase in the level of UG transcripts was detected in the proximal small intestine and colon, potentially due to a reduction in intestinal inflammation and/or neoplasia. Taken together, these results suggest that reductions in endogenous UG, accompanied by dysregulation in GC-C signaling, may be an early event in inflammation-promoted colorectal neoplasia; an event that can potentially be ameliorated by prophylactic intervention with plecanatide.
  
  
  CONCLUSIONS
  This study provides the first evidence that orally administered plecanatide reduces the multiplicity of inflammation-driven colonic dysplasia in mice, demonstrating the utility for developing GC-C agonists as chemopreventive agents.
authors.affiliation: Wen-Chi L Chang, Margie L Clapper, Cancer Prevention and Control Program, Fox Chase Cancer Center, Philadelphia, PA 19111, United States.
authors.forename: Wen-Chi L
authors.initials: WL
authors.lastname: Chang
authors.affiliation: Wen-Chi L Chang, Margie L Clapper, Cancer Prevention and Control Program, Fox Chase Cancer Center, Philadelphia, PA 19111, United States.
authors.forename: Shet
authors.initials: S
authors.lastname: Masih
authors.affiliation: Wen-Chi L Chang, Margie L Clapper, Cancer Prevention and Control Program, Fox Chase Cancer Center, Philadelphia, PA 19111, United States.
authors.forename: Anusha
authors.initials: A
authors.lastname: Thadi
authors.affiliation: Wen-Chi L Chang, Margie L Clapper, Cancer Prevention and Control Program, Fox Chase Cancer Center, Philadelphia, PA 19111, United States.
authors.forename: Viren
authors.initials: V
authors.lastname: Patwa
authors.affiliation: Wen-Chi L Chang, Margie L Clapper, Cancer Prevention and Control Program, Fox Chase Cancer Center, Philadelphia, PA 19111, United States.
authors.forename: Apoorva
authors.initials: A
authors.lastname: Joshi
authors.affiliation: Wen-Chi L Chang, Margie L Clapper, Cancer Prevention and Control Program, Fox Chase Cancer Center, Philadelphia, PA 19111, United States.
authors.forename: Harry S
authors.initials: HS
authors.lastname: Cooper
authors.affiliation: Wen-Chi L Chang, Margie L Clapper, Cancer Prevention and Control Program, Fox Chase Cancer Center, Philadelphia, PA 19111, United States.
authors.forename: Vaseem A
authors.initials: VA
authors.lastname: Palejwala
authors.affiliation: Wen-Chi L Chang, Margie L Clapper, Cancer Prevention and Control Program, Fox Chase Cancer Center, Philadelphia, PA 19111, United States.
authors.forename: Margie L
authors.initials: ML
authors.lastname: Clapper
authors.affiliation: Wen-Chi L Chang, Margie L Clapper, Cancer Prevention and Control Program, Fox Chase Cancer Center, Philadelphia, PA 19111, United States.
authors.forename: Kunwar
authors.initials: K
authors.lastname: Shailubhai
keywords: Colorectal cancer; Guanylate cyclase-C; Inflammation; Plecanatide; Uroguanylin