发布: 2019年05月20日第9卷第10期 DOI: 10.21769/BioProtoc.3235 浏览次数: 6032
评审: Mauro Sbroggio'Anonymous reviewer(s)
Abstract
Macropinocytosis has emerged as an important mechanism for non-selective route to internalize extracellular fluids and dissolved molecules in eukaryotic cell. As fundamental cellular behavior, macropinocytosis plays specific and distinct roles in many physiological and pathological processes, such as nutrients uptake, antigen presentation, pathogen capture, and tumorigenesis. It supports tumorigenesis by providing metabolic needs to dividing cells in Ras driven cancer. In recent years, macropinocytosis has gained considerable interest in physiology and various diseases, including cancer, neurodegenerative diseases and atherosclerosis, which in turn has led to the discovery of new endocytic recycling systems. Approaches to assess macropinocytosis will provide insight into its underlying regulatory molecular mechanisms and enable the physiological control of macropinocytosis for controlled drug delivery and targeted cancer therapy. Macropinocytosis is an important phenomenon in Ras-expressing cancer cells and, recently, we have revealed a functional role for macropinocytosis in cancer associated fibroblasts (CAFs) fueling cancer cell growth. Here, we describe a protocol for detection of macropinocytosis in prostatic fibroblasts in vitro by utilizing fluorescently-labeled, lysine-fixable, 70 kDa high molecular weight dextran. Macropinosomes are visualized as fluorescent intracellular puncta either by confocal or fluorescent microscopy. To follow, subsequent intracellular events and their underlying mechanisms after macropinosomes formation, we perform co-localization of quenched BSA (DQTM-BSA) along with dextran labeling in cancer associated fibroblasts. Our protocol provides a consistent way to understand macropinocytosis in wild type or genetic manipulated prostatic fibroblast.
Keywords: Macropinosomes (巨胞饮)Background
Macropinocytosis or ‘cell drinking’ is a type of endocytosis that involves the nonspecific uptake of extracellular fluid into large intracellular vesicles known as macropinosomes (Swanson and Watts, 1995). The macropinosomes are heterogeneous in size and shape, with their diameters ranging between 0.2 and 5 micrometers (Lim and Gleeson, 2011). The Src and Ras are prominent oncogenes which stimulate macropinocytosis in various type of cancer (Bar-Sagi and Feramisco, 1986). Macropinocytosis has been prominently described in pancreatic cancer cells, recognized for having active Ras signaling (Commisso et al., 2013; Davidson et al., 2017). We determined that epigenetic activation of Ras signaling mediates macropinocytosis in prostatic cancer associated fibroblasts resulting in albumin uptake, lysosomal degradation, and release of constituent amino acids (Mishra et al., 2018). These amino acids, predominantly glutamine, were found to support the metabolism and differentiation of the prostate cancer epithelial cells. Therefore, macropinocytosis is an important nutrient processing pathway to support the energetic needs of cancer associated fibroblasts (CAFs) and may represent a predictive biomarker for cancer therapy. The quantification of macropinocytosis can be achieved through confocal laser scanning microscopy.
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版权信息
© 2019 The Authors; exclusive licensee Bio-protocol LLC.
如何引用
Mishra, R. and Bhowmick, N. A. (2019). Visualization of Macropinocytosis in Prostate Fibroblasts. Bio-protocol 9(10): e3235. DOI: 10.21769/BioProtoc.3235.
分类
癌症生物学 > 癌症生物化学 > 耐药性
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