title: Combined Use of Gene Expression Modeling and siRNA Screening Identifies Genes and Pathways Which Enhance the Activity of Cisplatin When Added at No Effect Levels to Non-Small Cell Lung Cancer Cells In Vitro.
abstract: Platinum-based combination chemotherapy is the standard treatment for advanced non-small cell lung cancer (NSCLC). While cisplatin is effective, its use is not curative and resistance often emerges. As a consequence of microenvironmental heterogeneity, many tumour cells are exposed to sub-lethal doses of cisplatin. Further, genomic heterogeneity and unique tumor cell sub-populations with reduced sensitivities to cisplatin play a role in its effectiveness within a site of tumor growth. Being exposed to sub-lethal doses will induce changes in gene expression that contribute to the tumour cell's ability to survive and eventually contribute to the selective pressures leading to cisplatin resistance. Such changes in gene expression, therefore, may contribute to cytoprotective mechanisms. Here, we report on studies designed to uncover how tumour cells respond to sub-lethal doses of cisplatin. A microarray study revealed changes in gene expressions that occurred when A549 cells were exposed to a no-observed-effect level (NOEL) of cisplatin (e.g. the IC10). These data were integrated with results from a genome-wide siRNA screen looking for novel therapeutic targets that when inhibited transformed a NOEL of cisplatin into one that induced significant increases in lethality. Pathway analyses were performed to identify pathways that could be targeted to enhance cisplatin activity. We found that over 100 genes were differentially expressed when A549 cells were exposed to a NOEL of cisplatin. Pathways associated with apoptosis and DNA repair were activated. The siRNA screen revealed the importance of the hedgehog, cell cycle regulation, and insulin action pathways in A549 cell survival and response to cisplatin treatment. Results from both datasets suggest that RRM2B, CABYR, ALDH3A1, and FHL2 could be further explored as cisplatin-enhancing gene targets. Finally, pathways involved in repairing double-strand DNA breaks and INO80 chromatin remodeling were enriched in both datasets, warranting further research into combinations of cisplatin and therapeutics targeting these pathways.
authors.affiliation: Experimental Therapeutics, BC Cancer Research Centre, Vancouver, BC, Canada.|Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, BC, Canada.
authors.forename: Ada W Y
authors.initials: AW
authors.lastname: Leung
authors.affiliation: Centre for Lymphoid Cancers, BC Cancer Agency, Vancouver, BC, Canada.
authors.forename: Stacy S
authors.initials: SS
authors.lastname: Hung
authors.affiliation: Experimental Therapeutics, BC Cancer Research Centre, Vancouver, BC, Canada.
authors.forename: Ian
authors.initials: I
authors.lastname: Backstrom
authors.affiliation: Experimental Therapeutics, BC Cancer Research Centre, Vancouver, BC, Canada.
authors.forename: Daniel
authors.initials: D
authors.lastname: Ricaurte
authors.affiliation: Experimental Therapeutics, BC Cancer Research Centre, Vancouver, BC, Canada.
authors.forename: Brian
authors.initials: B
authors.lastname: Kwok
authors.affiliation: Molecular Oncology, BC Cancer Research Centre, Vancouver, BC, Canada.
authors.forename: Steven
authors.initials: S
authors.lastname: Poon
authors.affiliation: Molecular Oncology, BC Cancer Research Centre, Vancouver, BC, Canada.
authors.forename: Steven
authors.initials: S
authors.lastname: McKinney
authors.affiliation: Terry Fox Laboratory, BC Cancer Agency, Vancouver, BC, Canada.
authors.forename: Romulo
authors.initials: R
authors.lastname: Segovia
authors.affiliation: Experimental Therapeutics, BC Cancer Research Centre, Vancouver, BC, Canada.
authors.forename: Jenna
authors.initials: J
authors.lastname: Rawji
authors.affiliation: Experimental Therapeutics, BC Cancer Research Centre, Vancouver, BC, Canada.
authors.forename: Mohammed A
authors.initials: MA
authors.lastname: Qadir
authors.affiliation: Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, BC, Canada.|Molecular Oncology, BC Cancer Research Centre, Vancouver, BC, Canada.
authors.forename: Samuel
authors.initials: S
authors.lastname: Aparicio
authors.affiliation: Terry Fox Laboratory, BC Cancer Agency, Vancouver, BC, Canada.
authors.forename: Peter C
authors.initials: PC
authors.lastname: Stirling
authors.affiliation: Centre for Lymphoid Cancers, BC Cancer Agency, Vancouver, BC, Canada.
authors.forename: Christian
authors.initials: C
authors.lastname: Steidl
authors.affiliation: Experimental Therapeutics, BC Cancer Research Centre, Vancouver, BC, Canada.|Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, BC, Canada.|Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, BC, Canada.|Centre for Drug Research and Development, Vancouver, BC, Canada.
authors.forename: Marcel B
authors.initials: MB
authors.lastname: Bally
mesh_terms: D000970:Antineoplastic Agents / Q000737:chemistry*; D002135:Calcium-Binding Proteins / Q000235:genetics; D002289:Carcinoma, Non-Small-Cell Lung / Q000378:metabolism*; D018797:Cell Cycle Proteins / Q000235:genetics; D045744:Cell Line, Tumor / Q000187:drug effects; D002843:Chromatin / Q000378:metabolism; D002945:Cisplatin / Q000737:chemistry*; D053903:DNA Breaks, Double-Stranded; D004260:DNA Repair; D019008:Drug Resistance, Neoplasm; D004354:Drug Screening Assays, Antitumor; D020869:Gene Expression Profiling; D015972:Gene Expression Regulation, Neoplastic; D020868:Gene Silencing; D006801:Humans; D008175:Lung Neoplasms / Q000378:metabolism*; D010750:Phosphoproteins / Q000235:genetics; D034741:RNA, Small Interfering / Q000378:metabolism*; D012264:Ribonucleotide Reductases / Q000235:genetics
chemical_list: D000970:Antineoplastic Agents; C448922:CABYR protein, human; D002135:Calcium-Binding Proteins; D018797:Cell Cycle Proteins; D002843:Chromatin; D010750:Phosphoproteins; D034741:RNA, Small Interfering; C405947:RRM2B protein, human; D012264:Ribonucleotide Reductases; D002945:Cisplatin