Rhamnogalacturonan I containing homogalacturonan inhibits colon cancer cell proliferation by decreasing ICAM1 expression. (5th November 2015)

• Record Type: Journal Article
• Authors: Maxwell, Ellen G.; Colquhoun, Ian J.; Chau, Hoa K.; Hotchkiss, Arland T.; Waldron, Keith W.; Morris, Victor J.; Belshaw, Nigel J.
• Is Part Of: Carbohydrate polymers. Volume 132(2015)
• Page Start: 546
• Page End: 553
• Publication Date: 2015-11-05
• Subjects: Modified pectin -- Rhamnogalacturonan I -- Homogalacturonan -- Galactan -- Colon cancer -- ICAM1; Polysaccharides -- Periodicals; Polysaccharides -- Periodicals; Polysaccharides -- Périodiques; Electronic journals; 547.78
• DOI: 10.1016/j.carbpol.2015.06.082
• Languages: English
• ISSNs: 0144-8617

Abstract

Highlights: Pectin extracts representative of the structural components of whole pectin were characterised by HPAEC-PAD and NMR. RGI and galactan inhibited DLD1 and HCT116 colon cancer cell proliferation. RGI reduced ICAM1 gene expression in DLD1 cells. siRNA knockdown of ICAM1 expression in DLD1 cells significantly reduced cell viability. Hydrolysis of homogalacturonan in RGI abolished its effects on cancer cells. Abstract: Pectin modified with pH, heat or enzymes, has previously been shown to exhibit anti-cancer activity. However, the structural requirements for modified pectin bioactivity have rarely been addressed. In this study several pectin extracts representing different structural components of pectin were assessed for effects against colon cancer cells. Rhamnogalacturonan I (RGI) extracts reduced proliferation of DLD1 and HCT116 colon cancer cells in a dose- and time-dependent manner. RGI reduced ICAM1 gene expression and siRNA-mediated knockdown of ICAM1 expression decreased cell proliferation providing a potential novel mechanism for the anti-cancer activity of pectin. Structural analysis of bioactive and non-bioactive RGIs suggested that a homogalacturonan component is maybe essential for the anti-proliferative activity, furthering the understanding of the structural requirements for pectin bioactivity.