The effect of the acid-sensitivity of 4-(N)-stearoyl gemcitabine-loaded micelles on drug resistance caused by RRM1 overexpression

Saijie Zhu, Piyanuch Wonganan, Dharmika S.P. Lansakara-P., Hannah L. O'Mary, Yue Li, Zhengrong Cui

Research output: Contribution to journalArticlepeer-review

49 Scopus citations


Chemoresistance is a major issue for most gemcitabine-related chemotherapies. The overexpression of ribonucleotide reductase subunit M1 (RRM1) plays a key role in gemcitabine resistance. In this study, we synthesized a new highly acid-sensitive amphiphilic micelle material by conjugating hydrophilic polyethylene glycol with a hydrophobic stearic acid derivative (C18) using a hydrazone bond, which was named as PHC-2. A lipophilic prodrug of gemcitabine, 4-(N)-stearoyl gemcitabine (GemC18), was loaded into micelles prepared with PHC-2, a previously synthesized less acid-sensitive PHC-1, and their acid-insensitive counterpart, PAC. GemC18 loaded in acid-sensitive micelles can overcome gemcitabine resistance, and GemC18 in the highly acid-sensitive PHC-2 micelles was more cytotoxic than in the less acid-sensitive PHC-1 micelles. Mechanistic studies revealed that upon cellular uptake and lysosomal delivery, GemC18 in the acid-sensitive micelles was released and hydrolyzed more efficiently. Furthermore, GemC18 loaded in the highly acid-sensitive PHC-2 micelles inhibited the expression of RRM1 and increased the level of gemcitabine triphosphate (dFdCTP) in gemcitabine resistant tumor cells. The strategy of delivering lipophilized nucleoside analogs using highly acid-sensitive micelles may represent a new platform technology to increase the antitumor activity of nucleoside analogs and to overcome tumor cell resistance to them.

Original languageEnglish (US)
Pages (from-to)2327-2339
Number of pages13
Issue number9
StatePublished - Mar 2013
Externally publishedYes


  • Cell uptake
  • DFdCTP/dNTP ratio
  • Hydrazone
  • Intracellular metabolism
  • Lysosomes
  • Nucleoside analogs

ASJC Scopus subject areas

  • Mechanics of Materials
  • Ceramics and Composites
  • Bioengineering
  • Biophysics
  • Biomaterials


Dive into the research topics of 'The effect of the acid-sensitivity of 4-(N)-stearoyl gemcitabine-loaded micelles on drug resistance caused by RRM1 overexpression'. Together they form a unique fingerprint.

Cite this