| Summary: | 碩士 === 中國醫藥大學 === 營養學系碩士班 === 102 === Colon cancer, also known as colorectal cancer is a major cause of morbidity and mortality in Taiwan recent years. And colon cancer is also the third most commonly diagnosed cancer in the world, which is more common in developed countries. The major therapies for colon cancer are surgery, chemotherapy, and radiation. However, the conventional therapies have few side effects. Therefore, to minimise the adverse side effects, natural products or food componants derived chemotherapeutic agents are highly warrented.
The Wnt signaling pathway controls several cell processes, such as motility and proliferation during embryonic development. Wnt signaling is also involved in the maintenance of potency and the induction of differentiation in stem cells. Wnt/β-catenin activity depends on the amount of β-catenin located in the cytoplasm. In the absence of a Wnt ligand, a ‘destruction complex’ formed by APC, axis inhibitor (AXIN) and glycogen synthase kinase-3-β (GSK3-β) phosphorylates cytosolic b-catenin, which is subsequently degraded by the ubiquitin-proteasome system. EMT (Epithelial-to-mesenchymal transition) contributes to the complex architecture of the embryo by permitting the progression of embryogenesis from a simple single-cell layer epithelium to a complex three-dimensional organism composed of both epithelial and mesenchymal cells.
Antrodia camphorata (AC), a well known medical mushroom, native to Taiwan that has been used as Chinese folk medicine for many years. Most of the studies about AC focus on the effect on autophagy and apoptosis. However the ani-cancer potential of AC against colon cancer was poorly understood. Therefore, the goal of the present study was to address whether fermented culture broth extracts of A. camphorata (AC-10) and the pure comcound (AC-0) could inhibit the metastasis of colon cancer cell line.
The first part , we want to investigate if AC-10 can inhibits the metastasis of human colon cancer cells SW480 and SW620 through the down-regulation of Wnt/β-catenin signaling pathway or PI3K/Akt pathway. We observed AC-10 treatment decreased colon cancer cells viability with an IC90 value of (40、80、120 μg/mL). We also found that treatment with AC-10 significantly inhibited tumor cell invasion and colony formation in vitro. In addition, AC-10 treatment significantly increased epithelial cell protein expression, including E-cadherin, ZO-1 and occludin, and reduced mesenchymal cell proteins including ??-catenin, vimentin, MMP-2 and MMP-9 in human colon cancer cells SW620. Immunofluorescence analysis confirmed that treatment of AC-10 markedly reduced β-catenin translocation into the nucleus, and the cytosol and nuclear protein expression of β-catenin also decreased in a dose-dependant manner. Furthermore, the degradation of β-catenin can be reversed by MG-132, a proteasomal inhibitor. GSK3β inhibitor SB 216763, that the suppression of β-catenin degradation is dependant on by adding on GSK3β activity. The results indicated that AC-10 maybe the proteasomal degradation of β-catenin depend on the GSK3β mechanism. On the other side, we want to examine if AC-10 can inhibit colon cancer cell SW480 migration and invasion through PI3K/Akt pathway. We observed that treatment with AC-10 significantly decreased p-PI3K and p-Akt protein expression in dose- and time-dependant manner. Furthermore, the PI3K/Akt downstream protein expression: NFκB and ??-catenin also decreased. Immunofluorescence analysis confirmed that treatment of AC-10 markedly reduced NFκB translocation into the nucleus.
In the seconed part, AC-0, a pure compound derived from AC-10. It was also found to inhibit EMT related preoteins through the Wnt/??-catenin pathway, and suppress translocation of ??-catenin into nucleus. Like AC-10, AC-0 could inhibit the downstream protein expression of ??-catenin. Taken together, our data strongly suggest that AC-0 and AC-10 could inhibit metastasis of colon cancer cell SW620 via inhibition of Wnt/β-catenin signaling pathway, and AC-10 could inhibit metastasis of colon cancer cell SW480 via inhibition of PI3K/Akt signaling pathway. And they may be a promissing agent for the treatment of colon cancer.
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