Inactivation of the von Hippel–Lindau tumor suppressor leads to selective expression of a human endogenous retrovirus in kidney cancer

E Cherkasova, E Malinzak, S Rao, Y Takahashi… - Oncogene, 2011 - nature.com
E Cherkasova, E Malinzak, S Rao, Y Takahashi, VN Senchenko, AV Kudryavtseva…
Oncogene, 2011nature.com
A human endogenous retrovirus type E (HERV-E) was recently found to be selectively
expressed in most renal cell carcinomas (RCCs). Importantly, antigens derived from this
provirus are immunogenic, stimulating cytotoxic T cells that kill RCC cells in vitro and in vivo.
Here, we show HERV-E expression is restricted to the clear cell subtype of RCC (ccRCC)
characterized by an inactivation of the von Hippel–Lindau (VHL) tumor-suppressor gene
with subsequent stabilization of hypoxia-inducible transcription factors (HIFs)-1α and-2α …
Abstract
A human endogenous retrovirus type E (HERV-E) was recently found to be selectively expressed in most renal cell carcinomas (RCCs). Importantly, antigens derived from this provirus are immunogenic, stimulating cytotoxic T cells that kill RCC cells in vitro and in vivo. Here, we show HERV-E expression is restricted to the clear cell subtype of RCC (ccRCC) characterized by an inactivation of the von Hippel–Lindau (VHL) tumor-suppressor gene with subsequent stabilization of hypoxia-inducible transcription factors (HIFs)-1α and-2α. HERV-E expression in ccRCC linearly correlated with HIF-2α levels and could be silenced in tumor cells by either transfection of normal VHL or small interfering RNA inhibition of HIF-2α. Using chromatin immunoprecipitation, we demonstrated that HIF-2α can serve as transcriptional factor for HERV-E by binding with HIF response element (HRE) localized in the proviral 5′ long terminal repeat (LTR). Remarkably, the LTR was found to be hypomethylated only in HERV-E-expressing ccRCC while other tumors and normal tissues possessed a hypermethylated LTR preventing proviral expression. Taken altogether, these findings provide the first evidence that inactivation of a tumor suppressor gene can result in aberrant proviral expression in a human tumor and give insights needed for translational research aimed at boosting human immunity against antigenic components of this HERV-E.
nature.com