Phenotypic normalization of GN6TF rat liver tumor cells results from WT1 expression following transfection of human SYT13‐containing BACs

Abstract

We identified Synaptotagmin 13 (SYT13) as a putative liver tumor suppressor gene using a microcell hybrid model system and transfer of human 11p11.2 into GN6TF rat liver tumor cells. In the current study, bacterial artificial chromosomes (BACs) corresponding to various regions of human 11p11.2 (retrofitted with a G418 cassette) were transferred into GN6TF tumor cells to facilitate characterization of SYT13 tumor suppressor function under the control of its natural proximal and long-range cis controlling elements. Selected BAC clones contained SYT13 and different overlapping portions of surrounding genomic DNA (CTD-2255G20 and RP11-10C6). The control BAC (CTD-3154D11) contained proximal genes (LOC219638 and PRDM11), but not SYT13. G418-resistant BAC-transfected clones were identified that exhibited a normalized, flattened, contact-inhibited morphology, suggesting that SYT13 transfection normalizes GN6TF cells. In addition, the WT1 tumor suppressor gene was induced following transfection of SYT13-containing BACs. Transfer of human 11p11.2 into GN6TF cells results in a normalized cell phenotype in vitro and induction of WT1 gene expression. Thus, the results of the current study support our previous supposition that human SYT13 complements a molecular defect in GN6TF liver tumor cells and gives rise to tumor suppression through induction of rat WT1. Support: NIH CA78343.