Fhit loss‐associated initiation and progression of neoplasia in vitro. Issue 11 (3rd October 2016)

• Record Type: Journal Article
• Authors: Karras, Jenna R.; Schrock, Morgan S.; Batar, Bahadir; Zhang, Jie; La Perle, Krista; Druck, Teresa; Huebner, Kay
• Is Part Of: Cancer science. Volume 107:Issue 11(2016)
• Page Start: 1590
• Page End: 1598
• Publication Date: 2016-10-03
• Subjects: Cell transformation -- common fragile site -- genome instability -- kidney cell lines -- tumorigenicity; Cancer -- Periodicals; Neoplasms -- Periodicals; Research -- Periodicals; Electronic journals; 616.994005
• DOI: 10.1111/cas.13032
• Languages: English
• ISSNs: 1347-9032

Abstract

Abstract : The FHIT gene, encompassing an active common fragile site, FRA3B, is frequently silenced in preneoplasia and cancer, through gene rearrangement or methylation of regulatory sequences. Silencing of Fhit protein expression causes thymidine kinase 1 downregulation, resulting in dNTP imbalance, and spontaneous replication stress that leads to chromosomal aberrations, allele copy number variations, insertions/deletions, and single‐base substitutions. Thus, Fhit, which is reduced in expression in the majority of human cancers, is a genome "caretaker" whose loss initiates genome instability in preneoplastic lesions. To follow the early genetic alterations and functional changes induced by Fhit loss that may recapitulate the neoplastic process in vitro, we established epithelial cell lines from kidney tissues of Fhit−/− and +/+ mouse pups early after weaning, and subjected cell cultures to nutritional and carcinogen stress, which +/+ cells did not survive. Through transcriptome profiling and protein expression analysis, we observed changes in the Trp53/p21 and survivin apoptotic pathways in −/− cells, and in expression of proteins involved in epithelial–mesenchymal transition. Some Fhit‐deficient cell lines showed anchorage‐independent colony formation and increased invasive capacity in vitro . Furthermore, cells of stressed Fhit−/− cell lines formed s.c. and metastatic tumors in nude mice. Collectively, we show that Fhit loss and subsequent thymidine kinase 1 inactivation, combined with selective pressures, leads to neoplasia‐associated alterations in genes and gene expression patterns in vitro and in vivo . Abstract : We followed the early genetic alterations and functional changes induced by Fhit loss that may recapitulate the neoplastic process in vitro, by establishing epithelial cell lines from kidney tissues of Fhit−/− and +/+ mice. Some Fhit‐deficient cell lines demonstrated anchorage‐independent colony formation, increased invasive capacity in vitro, and formed subcutaneous and metastatic tumors in nude mice. Deregulation of the Fhit‐TK1 pathway, combined with selective pressures, leads to neoplasia‐associated alterations in gene expression patterns promoting transformation in vitro and in vivo.