鴻喜菇蛋白質對小鼠大腸癌CT26細胞生長抑制機制 及對Balb/c鼠之該腫瘤轉移抑制效果

Abstract

鴻喜菇為低熱量、低脂肪且蛋白質含量高的食用菇，在日本培育多年，長期以來被視為高級食材且不斷推廣，目前是我國國內新興栽培的食用菇之ㄧ。文獻指出鴻喜菇具有抗腫瘤及抗真菌等之功效。本實驗中，將探討鴻喜菇40~80%硫酸銨沉澱物對小鼠大腸癌CT26腫瘤細胞株生長抑制及抗轉移之效果。細胞實驗中，利用鴻喜菇40~80%硫酸銨沉澱物與CT26細胞共同培養不同時間，以MTT法觀察其生長抑制率，並探討其對CT26細胞週期之變化。結果顯示，鴻喜菇40~80%硫酸銨沉澱物具較高的直接生長抑制效果，在濃度為600 μg/mL的生長抑制率可達67.90%以上，再經由流式細胞儀分析可知，鴻喜菇40~80%硫酸銨沉澱物可將CT26細胞週期停滯於G2/M期，並且使其走向細胞凋亡。在動物實驗中，於Balb/c鼠尾靜脈注射CT26腫瘤細胞株，建立腫瘤轉移肺臟之模式，並餵食不同劑量之鴻喜菇40~80%硫酸銨沉澱物，以探討其抗腫瘤轉移之效果。結果顯示，有餵食鴻喜菇40~80%硫酸銨沉澱物之小鼠，其腫瘤轉移至肺臟之小節結數，會隨濃度增加抑制效果愈明顯(P<0.05)。另外，於顯微鏡下觀察小鼠之肺臟及腎臟病理組織切片，於肺臟組織切片圖中，可看到腫瘤轉移後使組織間質增厚產生病變之情形；而腎臟組織切片圖顯示組織並未有病變。

Hypsizigus marmoreus (HM), one of popular dietary mushrooms, contains high protein, low calorie, and low fat and has long been consumed in Japan. Several researches indicate that HM has antitumor and antifungal activities. In the present study, HM was used to study its antitumor activity in vitro and in vivo. First, 40~80% ammonium sulfate precipitates of cold-salt water extracts from HM were prepared and incubated with mouse colon CT26 cells to observe the changes in growth inhibition (%) for 24, 48 and 72 hr by MTT assay, followed by the cell cycle arrest by a Flow Cytometry. Results showed that remarkable growth inhibition, higher than 68 %, was observed when CT26 cells were incubated with 600 μg/mL of 40~80 % ammonium sulfate precipitates of cold-salt water extracts from HM. In addition, cell cycle arrest of CT26 cells at G2/M phase and apoptosis were induced. In vivo, pulmonary metastasis of CT26 tumor on male Balb/c mice orally administrated for 13 days with doses (200, 400 and 600 mg/kg bw/day) of ammonium sulfate precipitates of cold-salt water extracts from HM and injected (iv) with 1×105 CT26 cells via a tail vein was established to observe the results. Metastasic lung nodules in experimental group fed with 200, 400 or 600 mg/kg bw/day decreased in a dose-dependent manner, revealing the significant (p<0.05) anti-metastatic effect of HM proteins. Histopathologic results in lung was consistent with the finding in vivo. Insignificant changes in renal and immunohistograph were observed in mice at those three dosages.