Cellular uptake and intracellular trafficking of PEG-b-PLA polymeric micelles.
Besides as an inert carrier for hydrophobic anticancer agents, polymeric micelles composed of di-block copolymer poly(ethylene glycol)-poly(lactic acid) (PEG-b-PLA) function as biological response modifiers including reversal of multidrug resistance in cancer. However, the uptake mechanisms and the subsequent intracellular trafficking remain to be elucidated. In this paper, we found that the uptake of PEG-b-PLA polymeric micelles incorporating nile red (M-NR) was significantly inhibited by both dynamin inhibitor dynasore and dynamin-2 dominant negative mutant (dynamin-2 K44A). Exogenously expressed caveolin-1 colocalized with M-NR and upregulated M-NR internalization in HepG2 cells expressing low level of endogenous caveolin-1, while caveolin-1 dominant negative mutant (caveolin-1 Y14F) significantly downregulated M-NR internalization in C6 cells expressing high level of endogenous caveolin-1. Exogenously expressed clathrin light chain A (clathrin LCa) did not mainly colocalize with the internalized M-NR and had no effect on M-NR uptake. These results suggested that dynamin- and caveolin-dependent but clathrin-independent endocytosis was involved in M-NR cellular uptake. We further found that M-NR colocalized with lysosome and microtubulin after internalization.
National Engineering Research Center for Nanomedicine, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China.
Zhen
Z
Zhang
Xiaoqin
X
Xiong
Jiangling
J
Wan
Ling
L
Xiao
Lu
L
Gan
Youmei
Y
Feng
Huibi
H
Xu
Xiangliang
X
Yang
D000818:Animals; D045744:Cell Line, Tumor; D002966:Clathrin / Q000737:chemistry; D004305:Dose-Response Relationship, Drug; D018432:Drug Resistance, Multiple; D019008:Drug Resistance, Neoplasm; D034285:Dynamin II / Q000235:genetics; D004705:Endocytosis; D006367:HeLa Cells; D056945:Hep G2 Cells; D006801:Humans; D006835:Hydrazones / Q000737:chemistry; D007773:Lactates / Q000737:chemistry*; D008247:Lysosomes / Q000737:chemistry; D051379:Mice; D008823:Micelles; D010078:Oxazines / Q000494:pharmacology; D011092:Polyethylene Glycols / Q000737:chemistry*; D011108:Polymers / Q000737:chemistry*; D021381:Protein Transport; D051381:Rats
D002966:Clathrin; D006835:Hydrazones; D007773:Lactates; D008823:Micelles; C511794:N'-(3,4-dihydroxybenzylidene)-3-hydroxy-2-naphthahydrazide; D010078:Oxazines; D011108:Polymers; C088513:poly(lactic acid-ethylene glycol); D011092:Polyethylene Glycols; D034285:Dynamin II; C044808:nile red