Ellagitannin-rich cloudberry inhibits hepatocyte growth factor induced cell migration and phosphatidylinositol 3-kinase/AKT activation in colon carcinoma cells and tumors in Min mice.

Anne-Maria Pajari,Anne J Ridley,Tuuli Koivumäki,Ritu Garg,Lassi Paavolainen,Varpu Marjomäki,Elina Vaara,Anu Heiman-Lindh,Marja Mutanen,Essi Päivärinta

doi:10.18632/oncotarget.9724

Anne-Maria Pajari, Anne J Ridley + Show 8 more

Open Access

https://doi.org/10.18632/oncotarget.9724

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Abstract

Berries have been found to inhibit colon carcinogenesis in animal models, and thus represent a potential source of compounds for prevention and treatment of colorectal cancer. The mechanistic basis for their effects is not well understood. We used human colon carcinoma cells and Min mice to investigate the effects of ellagitannin-rich cloudberry (Rubus chamaemorus) extract on cancer cell migration and underlying cell signaling. Intrinsic and hepatocyte growth factor (HGF) -induced cell motility in human HT29 and HCA7 colon carcinoma cells was assessed carrying out cell scattering and scratch wound healing assays using time-lapse microscopy. Activation of Met, AKT, and ERK in cell lines and tumors of cloudberry-fed Min mice were determined using immunoprecipitation, Western blot and immunohistochemical analyses. Cloudberry extract significantly inhibited particularly HGF-induced cancer cell migration in both cell lines. Cloudberry extract inhibited the Met receptor tyrosine phosphorylation by HGF and strongly suppressed HGF-induced AKT and ERK activation in both HT29 and HCA7 cells. Consistently, cloudberry feeding (10% w/w freeze-dried berries in diet for 10 weeks) reduced the level of active AKT and prevented phosphoMet localization at the edges in tumors of Min mice. These results indicate that cloudberry reduces tumor growth and cancer cell motility by inhibiting Met signaling and consequent activation of phosphatidylinositol 3-kinase/AKT in vitro and in tumors in vivo. As the Met receptor is recognized to be a major target in cancer treatment, our results suggest that dietary phytochemicals may have therapeutic value in reducing cancer progression and metastasis.

Highlights

Hepatocyte growth factor (HGF) and its receptor the Met tyrosine kinase induce multiple cellular responses depending on the environmental context, including cell motility, survival, proliferation, morphogenesis and angiogenesis [1, 2]
We studied the effects of bilberry, lingonberry and cloudberry on intestinal tumorigenesis in the Male and female C57BL/6J-ApcMin/J (Min) mouse, an animal model carrying a heterozygous germline mutation in the Apc tumor suppressor gene, similar to human familial adenomatous polyposis (FAP) syndrome and the majority of sporadic colorectal cancer cases [21]
Densitometric analyses and quantification of band intensities from three independent experiments revealed a maximum of 77% reduction in the ratio of pAKT/ AKT levels (Figure 5B) and 79% reduction of pERK/ ERK (Figure 5C) in HT29 cells, and a maximum of 91% reduction of pAKT/AKT (Figure 5E) and 70% reduction of pERK/ERK (Figure 5F) in HCA7 cells. These results demonstrate that hepatocyte growth factor (HGF)-induced cell migration in HT29 and HCA7 cells is dependent on the activation of the phosphatidylinositol 3-kinase (PI3K)/AKT and Ras/ERK pathways, both of which contribute to HGF/Met-induced invasive growth program in cancer cells [4], and that inhibition of the activation of these pathways by cloudberry extract explains its restricting effects on cancer cell migration

Summary

Introduction

Hepatocyte growth factor (HGF) and its receptor the Met tyrosine kinase induce multiple cellular responses depending on the environmental context, including cell motility, survival, proliferation, morphogenesis and angiogenesis [1, 2]. Binding of HGF to Met leads to dimerization of the receptor and autophosphorylation of several tyrosine residues in the C-terminal tail, including two tyrosine residues (Y1349 and Y1356) that serve as www.impactjournals.com/oncotarget a docking site for adapter signaling molecules such as Grb-2, Gab-1 and Shc [5, 6]. These docking sites activate several key cell signaling pathways including Ras-ERK, phosphatidylinositol 3-kinase (PI3K)/AKT, phospholipase C, Src and STAT3 [4]. The unique ability of activated Met to induce cell motility and migration is considered to play an important role [1]

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