Basic Study
Copyright ©The Author(s) 2017. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastrointest Pharmacol Ther. Feb 6, 2017; 8(1): 47-59
Published online Feb 6, 2017. doi: 10.4292/wjgpt.v8.i1.47
Plecanatide-mediated activation of guanylate cyclase-C suppresses inflammation-induced colorectal carcinogenesis in Apc+/Min-FCCC mice
Wen-Chi L Chang, Shet Masih, Anusha Thadi, Viren Patwa, Apoorva Joshi, Harry S Cooper, Vaseem A Palejwala, Margie L Clapper, Kunwar Shailubhai
Wen-Chi L Chang, Margie L Clapper, Cancer Prevention and Control Program, Fox Chase Cancer Center, Philadelphia, PA 19111, United States
Shet Masih, Anusha Thadi, Viren Patwa, Apoorva Joshi, Baruch S. Blumberg Institute, Doylestown, PA 18902, United States
Harry S Cooper, Department of Pathology, Fox Chase Cancer Center, Philadelphia, PA 19111, United States
Vaseem A Palejwala, Kunwar Shailubhai, R and D Center, Synergy Pharmaceuticals Inc., Doylestown, PA 18902, United States
Author contributions: Chang WCL, Masih S, Thadi A, Patwa V, Joshi A, Cooper HS, Palejwala VA, Clapper ML and Shailubhai K contributed to study concept, design, data acquisition, analysis and interpretation; Chang WCL, Cooper HS, Palejwala VA, Clapper ML and Shailubhai K contributed to manuscript preparation, critical revision and provided important intellectual content.
Supported by National Cancer Institute (CA133689 to Kunwar Shailubhai, CA006927 to Fox Chase Cancer Center); and an appropriation from the Commonwealth of Pennsylvania (Fox Chase Cancer Center).
Institutional review board statement: Experiments reported in this manuscript did not involve human samples and hence institutional review is not applicable.
Conflict-of-interest statement: Shailubhai K and Palejwala V are employees of Synergy Pharmaceuticals; remaining authors have no conflict of interest.
Data sharing statement: No additional data are available.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Correspondence to: Kunwar Shailubhai, Doctor of Philosophy, Chief Scientific Officer, R and D Center, Synergy Pharmaceuticals Inc., 3805 Old Easton Road, Doylestown, PA 18902, United States. shailu@synergypharma.com
Telephone: +1-215-5896308 Fax: +1-215-5896309
Received: June 21, 2016
Peer-review started: June 24, 2016
First decision: August 11, 2016
Revised: September 5, 2016
Accepted: October 25, 2016
Article in press: October 27, 2016
Published online: February 6, 2017
Processing time: 213 Days and 15.5 Hours
Abstract
AIM

To evaluate the effect of orally administered plecanatide on colorectal dysplasia in Apc+/Min-FCCC mice with dextran sodium sulfate (DSS)-induced inflammation.

METHODS

Inflammation driven colorectal carcinogenesis was induced in Apc+/Min-FCCC mice 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+/MinFCCC mice 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.

CONCLUSION

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.

Keywords: Guanylate cyclase-C; Uroguanylin; Plecanatide; Inflammation; Colorectal cancer

Core tip: Plecanatide, an analog of human uroguanylin, binds and activates guanylate cyclase-C signaling to produce its anti-tumorigenic activity. This study provides the first evidence that oral treatment with plecanatide inhibits inflammation-driven colorectal carcinogenesis. The potential mechanism in Apc+/MinFCCC mice appears to be agonist-mediated activation of guanylate cyclase-C signaling, resulting in inhibition of Wnt/β-catenin pathway and downregulation of pro-inflammatory cytokines and growth factors.