Nucleotide-based therapies targeting clusterin chemosensitize human lung adenocarcinoma cells both in vitro and in vivo.
BACKGROUND
Lung cancer is highly lethal and resistant to most anticancer interventions. Treatment resistance is mediated, in part, by enhanced expression of cell survival proteins that help facilitate tumor progression. Clusterin is a stress-associated cytoprotective protein up-regulated by various apoptotic triggers in many cancers and confers treatment resistance when overexpressed. The objectives in this study were to evaluate clusterin expression levels in human lung cancer tissue, and to test effects of clusterin silencing using antisense oligonucleotides (ASOs) and short interfering double-stranded RNAs (siRNAs) on chemosensitivity in human lung cancer A549 cells.


METHODS
Clusterin immunostaining was evaluated in a tissue microarray of 149 spotted human lung cancers. The effects of clusterin ASO or siRNA treatment on clusterin expression and chemosensitivity to paclitaxel was examined in A549 cells in vitro while the ability of clusterin ASO to chemosensitize in vivo was evaluated in immunocompromised mice bearing A549 tumors.


RESULTS
More than 80% of human non-small cell lung cancers are immunoreactive for clusterin. Clusterin ASO or siRNA decreased clusterin mRNA expression in A549 cells >75% in a dose-dependent, sequence-specific manner, and significantly enhanced chemosensitivity to paclitaxel in vitro. Characteristic apoptotic DNA laddering was observed after combined treatment with ASO plus paclitaxel, but not with either agent alone. In vivo administration of clusterin ASO, compared to mismatch control oligonucleotide, synergistically enhanced the effects of paclitaxel or gemcitibine to significantly delay A549 tumor growth.


CONCLUSIONS
These findings identify clusterin as a valid therapeutic target in strategies employing novel multimodality therapy for advanced lung cancer.
July
Laura V
LV
The Prostate Centre, Department of Surgery (Divisions of Urology and Thoracic Surgery), Vancouver Hospital and Health Sciences Centre, University of British Columbia, Vancouver, BC, Canada.
Beraldi
Eliana
E
So
Alan
A
Fazli
Ladan
L
Evans
Kenneth
K
English
John C
JC
Gleave
Martin E
ME
D000230:Adenocarcinoma / Q000188:drug therapy* / Q000628:therapy*; D000818:Animals; D000964:Antimetabolites, Antineoplastic / Q000494:pharmacology; D000972:Antineoplastic Agents, Phytogenic / Q000494:pharmacology; D017209:Apoptosis; D015152:Blotting, Northern; D045744:Cell Line, Tumor; D051152:Clusterin; D004396:Coloring Agents / Q000494:pharmacology; D004247:DNA / Q000235:genetics; D053938:DNA Fragmentation; D003841:Deoxycytidine / Q000031:analogs & derivatives* / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D006023:Glycoproteins / Q000235:genetics / Q000378:metabolism / Q000627:therapeutic use*; D006801:Humans; D007150:Immunohistochemistry; D066298:In Vitro Techniques; D008175:Lung Neoplasms / Q000188:drug therapy* / Q000628:therapy*; D051379:Mice; D018832:Molecular Chaperones / Q000235:genetics / Q000378:metabolism / Q000627:therapeutic use*; D009711:Nucleotides / Q000627:therapeutic use*; D020411:Oligonucleotide Array Sequence Analysis; D017239:Paclitaxel / Q000494:pharmacology; D034622:RNA Interference; D012330:RNA, Double-Stranded / Q000235:genetics; D034741:RNA, Small Interfering / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013778:Tetrazolium Salts / Q000494:pharmacology; D013844:Thiazoles / Q000494:pharmacology; D013997:Time Factors; D000093542:Gemcitabine
D000964:Antimetabolites, Antineoplastic; D000972:Antineoplastic Agents, Phytogenic; C495242:CLU protein, human; C495243:Clu protein, mouse; D051152:Clusterin; D004396:Coloring Agents; D006023:Glycoproteins; D018832:Molecular Chaperones; D009711:Nucleotides; D012330:RNA, Double-Stranded; D034741:RNA, Small Interfering; D013778:Tetrazolium Salts; D013844:Thiazoles; D003841:Deoxycytidine; D004247:DNA; C022616:thiazolyl blue; D017239:Paclitaxel; D000093542:Gemcitabine