這篇論文描述了向癌細(xì)胞供應(yīng)養(yǎng)分的一個(gè)以前沒(méi)有被識(shí)別出來(lái)的通道,。致癌的Ras蛋白已知促進(jìn)“巨胞飲”（macropinocytosis）。這是一個(gè)“內(nèi)吞”過(guò)程,，在其中,，細(xì)胞外流體及其成分通過(guò)名為“巨胞飲小體”（macropinosome）的小泡被內(nèi)化到細(xì)胞中。
現(xiàn)在,，Dafna Bar-Sagi及其同事發(fā)現(xiàn),，被Ras改變的細(xì)胞可利用這一過(guò)程來(lái)“吃”細(xì)胞外蛋白。被“巨胞飲”的蛋白發(fā)生降解,，產(chǎn)生支持腫瘤生長(zhǎng)所必需的自由氨基酸,。這一發(fā)現(xiàn)表明，“巨胞飲”的抑制對(duì)于治療一個(gè)亞組的癌癥可能會(huì)有效,。（生物谷Bioon.com）
生物谷推薦英文摘要：
Nature doi:10.1038/nature12138
Macropinocytosis of protein is an amino acid supply route in Ras-transformed cells
Cosimo Commisso, Shawn M. Davidson, Rengin G. Soydaner-Azeloglu, Seth J. Parker, Jurre J. Kamphorst, Sean Hackett, Elda Grabocka, Michel Nofal, Jeffrey A. Drebin, Craig B. Thompson, Joshua D. Rabinowitz, Christian M. Metallo, Matthew G. Vander Heiden & Dafna Bar-Sagi
Macropinocytosis is a highly conserved endocytic process by which extracellular fluid and its contents are internalized into cells through large, heterogeneous vesicles known as macropinosomes. Oncogenic Ras proteins have been shown to stimulate macropinocytosis but the functional contribution of this uptake mechanism to the transformed phenotype remains unknown. Here we show that Ras-transformed cells use macropinocytosis to transport extracellular protein into the cell. The internalized protein undergoes proteolytic degradation, yielding amino acids including glutamine that can enter central carbon metabolism. Accordingly, the dependence of Ras-transformed cells on free extracellular glutamine for growth can be suppressed by the macropinocytic uptake of protein. Consistent with macropinocytosis representing an important route of nutrient uptake in tumours, its pharmacological inhibition compromises the growth of Ras-transformed pancreatic tumour xenografts. These results identify macropinocytosis as a mechanism by which cancer cells support their unique metabolic needs and point to the possible exploitation of this process in the design of anticancer therapies.
