Identification of candidate liver tumor suppressor genes from human 11p11.2 by transcription mapping of microcell hybrid cell lines

Jahn, Jennifer E.; Ricketts, Sharon L.; Coleman, William B.

doi:10.3892/ijo.22.6.1303

Cited by 1 publication

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“…Microcell hybrid cell lines were established from GN6TF rat liver tumor cells (8,13) by microcellmediated chromosome transfer of human chromosome 11, using established methods (17,18). Clonal GN6TF-11 neo microcell hybrid cell lines used for chromosome deletion and transcription mapping have been described (11). In the current study, GN6TF-11 neo CX4 cells were transfected with shRNA expression constructs (as described below).…”

Section: Methodsmentioning

confidence: 99%

“…Successfully transfected cells were selected in 180 μg/ml Zeocin (InvivoGen), and individual cell lines (designated with the prefix SYT13-i and SYT13-s, respectively) were clonally isolated and maintained in culture as previously described (11). neo CX4 mRNA using the Comparative (2 ΔΔCt ) method described in User Bulletin #2: ABI Prism 7700 Sequence Detection System.…”

Section: Methodsmentioning

confidence: 99%

“…SYT13 mRNA was detected in 100% of suppressed microcell hybrid cell lines and was absent in all non-suppressed clones, including a non-suppressed microcell hybrid cell line that contains chromosome 11 with an interstitial deletion at the suppressive 11p11.2 locus (11,13). Finally, SYT13 expression was lost in all microcell hybrid-derived tumor cell lines examined, coordinate with reexpression of the tumorigenic phenotype (11). Based on its differential expression among microcell hybrid cell lines, SYT13 emerged as an excellent candidate for the human 11p11.2 liver tumor suppressor gene.…”

Section: Introductionmentioning

confidence: 99%

“…Subsequently, transcription mapping identified several candidate 11p11.2 tumor suppressor genes (including TP53I11, PRDM11, LOC219638 and SYT13) that were expressed in a panel of suppressed microcell hybrid cell lines (11,12). SYT13 mRNA was detected in 100% of suppressed microcell hybrid cell lines and was absent in all non-suppressed clones, including a non-suppressed microcell hybrid cell line that contains chromosome 11 with an interstitial deletion at the suppressive 11p11.2 locus (11,13). Finally, SYT13 expression was lost in all microcell hybrid-derived tumor cell lines examined, coordinate with reexpression of the tumorigenic phenotype (11).…”

Section: Introductionmentioning

confidence: 99%

“…Genomic mapping localized the liver tumor suppressor locus to a small (<1 Mbp) region of human chromosome 11p11.2 containing a number of candidate genes (9,10). Subsequently, transcription mapping identified several candidate 11p11.2 tumor suppressor genes (including TP53I11, PRDM11, LOC219638 and SYT13) that were expressed in a panel of suppressed microcell hybrid cell lines (11,12). SYT13 mRNA was detected in 100% of suppressed microcell hybrid cell lines and was absent in all non-suppressed clones, including a non-suppressed microcell hybrid cell line that contains chromosome 11 with an …”

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Re-expression of tumorigenicity after attenuation of human synaptotagmin 13 in a suppressed microcell hybrid cell line

Jahn

Coleman²

2008

Int J Oncol

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Abstract. Human chromosome 11p11.2 contains a putative liver tumor suppressor locus that was identified using a microcell hybrid cell line-based model of tumor suppression. Transcription mapping of suppressed microcell hybrid cell lines suggests that human SYT13 represents a strong candidate for the 11p11.2 tumor suppressor gene. Other evidence suggests that the putative 11p11.2 tumor suppressor gene (SYT13 or some other) may modulate the tumorigenic potential of neoplastic liver cell lines through direct or indirect regulation of the rat Wt1 tumor suppressor gene. To characterize a functional role for SYT13 in liver tumor suppression, we employed RNAi to attenuate SYT13 expression in a suppressed microcell hybrid cell line (GN6TF-11 neo CX4). SYT13-attenuated cells display aggressive phenotypic properties that are similar to or indistinguishable from the parental tumor cells (GN6TF), including altered cellular morphologies, disrupted contact inhibition, elevated saturation densities, restoration of anchorage-independent growth and increased tumorigenicity in vivo. Moreover, SYT13 attenuation and re-expression of tumorigenicity in GN6TF-11 neo CX4-derived cell lines was accompanied by a significant decrease of Wt1 expression. In contrast, the phenotypic properties of scrambled-control cells were similar to the suppressed microcell hybrid cells and Wt1 expression was unaffected. These observations combine to establish that: i) human SYT13 functions as a liver tumor suppressor gene that complements a molecular defect in GN6TF rat liver tumor cells resulting in a normalized cellular phenotype in vitro and suppression of tumorigenicity in vivo; ii) RNAi-mediated attenuation of SYT13 expression restores the neoplastic phenotype of GN6TF-11 neo CX4 microcell hybrid cells, consistent with the function of a liver tumor suppressor gene; and iii) loss of Wt1 expression is important for the re-establishment of tumorigenic potential by GN6TF-11 neo CX4 microcell hybrid cells after attenuation of SYT13. IntroductionHepatocellular carcinogenesis is a multi-step process that results from altered expression of multiple genes as a consequence of genetic mutations, epigenetic mechanisms, and/or chromosomal aberrations affecting a number of chromosome arms (1,2), including chromosome 11p (3-6).Comparative mapping studies suggest strongly that hepatocarcinogenesis in humans and rodents may be governed by orthologous tumor suppressor genes (7). We exploited this supposition to identify human liver tumor suppressor genes using a functional model for tumor suppression based on microcell-mediated transfer of human chromosome 11 into the aggressive rat liver tumor cell line GN6TF (8). The resulting microcell hybrid cell lines exhibit normalized cellular morphology, re-expression of contact inhibition, complete loss of anchorage-independent growth potential, and decreased tumorigenicity in vivo, suggesting that human chromosome 11 contains one or more liver tumor suppressor genes (8). Genomic mapping localized the liver tumor suppressor ...

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%