TY - JOUR
T1 - A Synthetic Lethality Screen Using a Focused siRNA Library to Identify Sensitizers to Dasatinib Therapy for the Treatment of Epithelial Ovarian Cancer
AU - Pathak, Harsh B.
AU - Zhou, Yan
AU - Sethi, Geetika
AU - Hirst, Jeff J.
AU - Schilder, Russell J.
AU - Golemis, Erica A.
AU - Godwin, Andrew K.
N1 - Publisher Copyright:
© 2015 Pathaket al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
PY - 2015/12/1
Y1 - 2015/12/1
N2 - Molecular targeted therapies have been the focus of recent clinical trials for the treatment of patients with recurrent epithelial ovarian cancer (EOC). The majority have not fared well as monotherapies for improving survival of these patients. Poor bioavailability, lack of predictive biomarkers, and the presence of multiple survival pathways can all diminish the success of a targeted agent. Dasatinib is a tyrosine kinase inhibitor of the Src-family kinases (SFK) and in preclinical studies shown to have substantial activity in EOC. However, when evaluated in a phase 2 clinical trial for patients with recurrent or persistent EOC, it was found to have minimal activity.We hypothesized that synthetic lethality screens performed using a cogently designed siRNA library would identify second-site molecular targets that could synergize with SFK inhibition and improve dasatinib efficacy. Using a systematic approach, we performed primary siRNA screening using a library focused on 638 genes corresponding to a network centered on EGFR, HER2, and the SFK-scaffolding proteins BCAR1, NEDD9, and EFS to screen EOC cells in combination with dasatinib. We followed up with validation studies including deconvolution screening, quantitative PCR to confirm effective gene silencing, correlation of gene expression with dasatinib sensitivity, and assessment of the clinical relevance of hits using TCGA ovarian cancer data. A refined list of five candidates (CSNK2A1, DAG1, GRB2, PRKCE, and VAV1) was identified as showing the greatest potential for improving sensitivity to dasatinib in EOC. Of these, CSNK2A1, which codes for the catalytic alpha subunit of protein kinase CK2, was selected for additional evaluation. Synergistic activity of the clinically relevant inhibitor of CK2, CX-4945, with dasatinib in reducing cell proliferation and increasing apoptosis was observed across multiple EOC cell lines. This overall approach to improving drug efficacy can be applied to other targeted agents that have similarly shown poor clinical activity.
AB - Molecular targeted therapies have been the focus of recent clinical trials for the treatment of patients with recurrent epithelial ovarian cancer (EOC). The majority have not fared well as monotherapies for improving survival of these patients. Poor bioavailability, lack of predictive biomarkers, and the presence of multiple survival pathways can all diminish the success of a targeted agent. Dasatinib is a tyrosine kinase inhibitor of the Src-family kinases (SFK) and in preclinical studies shown to have substantial activity in EOC. However, when evaluated in a phase 2 clinical trial for patients with recurrent or persistent EOC, it was found to have minimal activity.We hypothesized that synthetic lethality screens performed using a cogently designed siRNA library would identify second-site molecular targets that could synergize with SFK inhibition and improve dasatinib efficacy. Using a systematic approach, we performed primary siRNA screening using a library focused on 638 genes corresponding to a network centered on EGFR, HER2, and the SFK-scaffolding proteins BCAR1, NEDD9, and EFS to screen EOC cells in combination with dasatinib. We followed up with validation studies including deconvolution screening, quantitative PCR to confirm effective gene silencing, correlation of gene expression with dasatinib sensitivity, and assessment of the clinical relevance of hits using TCGA ovarian cancer data. A refined list of five candidates (CSNK2A1, DAG1, GRB2, PRKCE, and VAV1) was identified as showing the greatest potential for improving sensitivity to dasatinib in EOC. Of these, CSNK2A1, which codes for the catalytic alpha subunit of protein kinase CK2, was selected for additional evaluation. Synergistic activity of the clinically relevant inhibitor of CK2, CX-4945, with dasatinib in reducing cell proliferation and increasing apoptosis was observed across multiple EOC cell lines. This overall approach to improving drug efficacy can be applied to other targeted agents that have similarly shown poor clinical activity.
KW - Antineoplastic Agents/pharmacology
KW - Antineoplastic Combined Chemotherapy Protocols
KW - Apoptosis
KW - Carcinoma, Ovarian Epithelial
KW - Casein Kinase II/antagonists & inhibitors
KW - Cell Line, Tumor
KW - Cell Proliferation/drug effects
KW - Dasatinib/pharmacology
KW - Drug Synergism
KW - Dystroglycans/antagonists & inhibitors
KW - Female
KW - GRB2 Adaptor Protein/antagonists & inhibitors
KW - Gene Library
KW - Humans
KW - Naphthyridines/pharmacology
KW - Neoplasms, Glandular and Epithelial/drug therapy
KW - Ovarian Neoplasms/drug therapy
KW - Phenazines
KW - Protein Kinase C-epsilon/antagonists & inhibitors
KW - Proto-Oncogene Proteins c-vav/antagonists & inhibitors
KW - RNA, Small Interfering/metabolism
UR - http://www.scopus.com/inward/record.url?scp=84955605071&partnerID=8YFLogxK
UR - https://pubmed.ncbi.nlm.nih.gov/26637171/
U2 - 10.1371/journal.pone.0144126
DO - 10.1371/journal.pone.0144126
M3 - Article
C2 - 26637171
SN - 1932-6203
VL - 10
SP - e0144126
JO - PLoS ONE
JF - PLoS ONE
IS - 12
M1 - e0144126
ER -