PLGA nanoparticles codeliver paclitaxel and Stat3 siRNA to overcome cellular resistance in lung cancer cells.
BACKGROUND
Effective cancer chemotherapy remains an important issue in cancer treatment, and signal transducer and activator of transcription-3 (Stat3) activation leads to cellular resistance of anticancer agents. Polymers are ideal vectors to carry both chemotherapeutics and small interfering ribonucleic acid (siRNA) to enhance antitumor efficacy. In this paper, poly(lactic-co-glycolic acid) (PLGA) nanoparticles loaded with paclitaxel and Stat3 siRNA were successfully synthesized, and their applications in cancer cells were investigated.


METHODS
Firstly, paclitaxel was enclosed by PLGA nanoparticles through solvent evaporation. They were then coated with cationic polyethylenimine polymer (PLGA-PEI-TAX), enabling it to carry Stat3 siRNA on its surface through electrostatic interactions (PLGA-PEI-TAX-S3SI). The size, zeta potential, deliver efficacy, and release profile of the PLGA nanocomplexes were characterized in vitro. The cellular uptake, intracellular nanoparticle trajectory, and subsequent cellular events were evaluated after treatment with various PLGA nanocomplexes in human lung cancer A549 cells and A549-derived paclitaxel-resistant A549/T12 cell lines with α-tubulin mutation.


RESULTS
A549 and A549/T12 cells contain constitutively activated Stat3, and silencing Stat3 by siRNA made both cancer cells more sensitive to paclitaxel. Therefore, PLGA-PEI-TAX-S3SI was synthesized to test its therapeutic role in A549 and A549/T12 cells. Transmission electron microscopy showed the size of PLGA-PEI-TAX-S3SI to be around 250 nm. PLGA-PEI nanoparticles were nontoxic. PLGA-PEI-TAX was taken up by A549 and A549/T12 cells more than free paclitaxel, and they induced more condensed microtubule bundles and had higher cytotoxicity in these cancer cells. Moreover, the yellowish fluorescence observed in the cytoplasm of the cancer cells indicates that the PLGA-PEI nanoparticles were still simultaneously delivering Oregon Green paclitaxel and cyanine-5-labeled Stat3 siRNA 3 hours after treatment. Furthermore, after the cancer cells were incubated with the synthesized PLGA nanocomplexes, PLGA-PEI-TAX-S3SI suppressed Stat3 expression and induced more cellular apoptosis in A549 and A549/T12 cells compared with PLGA-PEI-TAX.


CONCLUSIONS
The PLGA-PEI-TAX-S3SI complex provides a new therapeutic strategy to control cancer cell growth.
Graduate Institute of Clinical Medicine, College of Medicine, National Cheng Kung University, 35 Xiaodong Rd., Tainan, Taiwan.
Wen-Pin
WP
Su
Fong-Yu
FY
Cheng
Dar-Bin
DB
Shieh
Chen-Sheng
CS
Yeh
Wu-Chou
WC
Su
D045744:Cell Line, Tumor; D019008:Drug Resistance, Neoplasm; D006801:Humans; D019344:Lactic Acid / Q000008:administration & dosage* / Q000737:chemistry; D008175:Lung Neoplasms / Q000188:drug therapy / Q000235:genetics / Q000378:metabolism / Q000628:therapy*; D053758:Nanoparticles / Q000008:administration & dosage* / Q000737:chemistry; D017239:Paclitaxel / Q000008:administration & dosage* / Q000737:chemistry / Q000493:pharmacokinetics; D011100:Polyglycolic Acid / Q000008:administration & dosage* / Q000737:chemistry; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D034741:RNA, Small Interfering / Q000008:administration & dosage* / Q000737:chemistry / Q000235:genetics / Q000493:pharmacokinetics; D050796:STAT3 Transcription Factor / Q000235:genetics*
D034741:RNA, Small Interfering; D050796:STAT3 Transcription Factor; C494086:STAT3 protein, human; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011100:Polyglycolic Acid; D019344:Lactic Acid; D017239:Paclitaxel