Lymphomas that recur after MYC suppression continue to exhibit oncogene addiction

ABSTRACT: The suppression of oncogenic levels of MYC is sufficient to induce sustained tumor regression associated with proliferative arrest, differentiation, cellular senescence and/or apoptosis, a phenomenon known as oncogene addiction. However, after prolonged inactivation of MYC in a conditional transgenic mouse model of Em-tTA/tetO-MYC T-acute lymphomablastic lymphoma (T-ALL), some of the tumors recur, recapitulating what is frequently observed in human tumors in response to targeted therapies. Here we report that these recurring lymphomas express high levels of either transgenic or endogenous Myc suggesting that tumors continue to be addicted to oncogenic levels of MYC. Many of the recurring lymphomas (76%) harbored mutations in the tetracycline transactivator (tTA) resulting in expression of the MYC transgene even in the presence of doxycycline. Many of the remaining recurring tumors expressed high levels of endogenous Myc which was in some cases associated with a genomic rearrangement of the endogenous Myc locus or overexpression of Notch1. Gene expression profiling confirmed that the primary and recurring tumors have highly similar transcriptomes. Importantly, shRNA-mediated suppression of the high levels of MYC in recurring tumors elicited both suppression of proliferation and increased apoptosis confirming that these tumors remain oncogene addicted. These results suggest that tumors caused by MYC overexpression remain addicted to high levels of expression of this oncogene.

ORGANISM(S): Mus musculus

PROVIDER: GSE32341 | GEO | 2011/09/24

SECONDARY ACCESSION(S): PRJNA147253

REPOSITORIES: GEO