A novel gammaretroviral shuttle vector insertional mutagenesis screen identifies SHARPIN as a breast cancer metastasis gene and prognostic biomarker.
Breast cancer (BC) is the second leading cause of malignancy among U.S. women. Metastasis results in a poor prognosis and increased mortality, but the molecular mechanisms by which metastatic tumors occur are not well understood. Identifying the genes that drive the metastatic process could provide targets for improved therapy and biomarkers to improve BC patient outcomes. Using a forward mutagenesis screen, BC cells mutagenized with a replication-incompetent gammaretroviral vector (γRV) were xenotransplanted into the mammary fat pad of immunodeficient mice. In this approach the vector provirus dysregulates nearby genes, providing a selective advantage to transduced cells to form metastases. Metastatic tumors were analyzed for proviral integration sites to identify nearby candidate metastasis genes. The γRV has a transgene cassette that allows for rescue in bacteria and rapid identification of vector integration sites. Using this approach, we identified the previously described metastasis gene WWTR1 (TAZ), and three other novel candidate metastasis genes including SHARPIN. SHARPIN was independently validated in vivo as a BC metastasis gene. Analysis of patient data showed that SHARPIN expression predicts metastasis-free survival after adjuvant therapy. Our approach has broad potential to identify genes involved in oncogenic processes for BC and other cancers. We show here it can identify both known (WWTR1) and novel (SHARPIN) BC metastasis genes.
Washington State University College of Pharmacy, WSU Spokane, Spokane, WA, USA.
Victor M
VM
Bii
Washington State University College of Pharmacy, WSU Spokane, Spokane, WA, USA.
Dustin T
DT
Rae
Washington State University College of Pharmacy, WSU Spokane, Spokane, WA, USA.|School of Molecular Biosciences, Washington State University, Pullman, Washington, USA.
Grant D
GD
Trobridge
D000818:Animals; D001483:Base Sequence; D014408:Biomarkers, Tumor / Q000235:genetics*; D001943:Breast Neoplasms / Q000235:genetics* / Q000473:pathology; D045744:Cell Line, Tumor; D017988:Gammaretrovirus / Q000235:genetics*; D015972:Gene Expression Regulation, Neoplastic; D005822:Genetic Vectors / Q000235:genetics; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics; D053208:Kaplan-Meier Estimate; D008969:Molecular Sequence Data; D016254:Mutagenesis, Insertional; D009362:Neoplasm Metastasis; D011379:Prognosis; D034622:RNA Interference; D000067492:RNAi Therapeutics / Q000379:methods; D015534:Trans-Activators; D014157:Transcription Factors; D000091364:Transcriptional Coactivator with PDZ-Binding Motif Proteins; D014452:Ubiquitins / Q000235:genetics*; D023041:Xenograft Model Antitumor Assays / Q000379:methods
D014408:Biomarkers, Tumor; D047908:Intracellular Signaling Peptides and Proteins; C575183:SHARPIN protein, human; D015534:Trans-Activators; D014157:Transcription Factors; D000091364:Transcriptional Coactivator with PDZ-Binding Motif Proteins; D014452:Ubiquitins; C551991:WWTR1 protein, human
Chromosome Section; breast cancer; gammaretroviral vector (γRV); insertional mutagenesis screen; metastasis; prognostic biomarker