Oncogene-induced replication stress characterizes many aggressive cancers. Several treatments are being developed that target replication stress, however, identification of tumors with high levels of replication stress remains challenging.
We describe a gene expression signature of oncogene-induced replication stress. A panel of triple-negative breast cancer (TNBC) and non-transformed cell lines were engineered to overexpress
CDC25A
,
CCNE1
or
MYC,
which resulted in slower replication kinetics. RNA sequencing analysis revealed a set of 52 commonly upregulated genes. In parallel, mRNA expression analysis of patient-derived tumor samples (TCGA, n=10,592) also revealed differential gene expression in tumors with amplification of oncogenes that trigger replication stress (
CDC25A
,
CCNE1
,
MYC
,
CCND1
,
MYB
,
MOS
,
KRAS
,
ERBB2
, and
E2F1
). Upon integration, we identified a six-gene signature of oncogene-induced replication stress (
NAT10
,
DDX27
,
ZNF48
,
C8ORF33
,
MOCS3,
and
MPP6)
. Immunohistochemical analysis of NAT10 in breast cancer samples (n=330) showed strong correlation with expression of phospho-RPA (R=0.451, p=1.82x10
-20
) and γH2AX (R=0.304, p=2.95x10
-9
). Finally, we applied our oncogene-induced replication stress signature to patient samples from TCGA (n=8,862) and GEO (n=13,912) to define the levels of replication stress across 27 tumor subtypes, identifying diffuse large B cell lymphoma, ovarian cancer, TNBC and colorectal carcinoma as cancer subtypes with high levels of oncogene-induced replication stress.