Oncogene database

332

BIRC5

baculoviral IAP repeat containing 5;BIRC5;baculoviral IAP repeat containing 5

apoptosis inhibitor 4|apoptosis inhibitor survivin|baculoviral IAP repeat-containing protein 5|survivin variant 3 alpha

17q25

protein-coding

Gain of chromosome 17q correlates with high-stage disease, an adverse clinical outcome and leads to the overexpression of the antiapoptotic protein BIRC5/Survivin in neuroblastoma (NB). We have shown before that Survivin defines a threshold for the sensitivity of NB cells to DNA-damaging chemotherapeutic agents that require FOXO3 activation for apoptosis induction. To investigate the molecular basis of apoptosis inhibition we analyzed the function of Survivin at mitochondria and uncovered that Survivin induces mitochondrial fragmentation, reduces mitochondrial respiration and represses BCL2L11/Bim. Mitochondrial fission depends on Survivin-induced recruitment of the fission regulator DNM1L/Drp1 to mitochondria. In parallel, Survivin expression inhibits the respiratory complex-I, thereby preventing reactive oxygen species accumulation and, as a consequence, FOXO3-induced apoptosis. The loss of energy production via oxidative phosphorylation is compensated by increased glycolysis in Survivin-overexpressing NB tumor cells. Glycolysis inhibitors neutralize the antiapoptotic effect of Survivin and sensitize high-stage NB to DNA-damaging drugs. This suggests that glycolysis inhibitors target an archilles heel of Survivin-overexpressing NB and may be highly useful as chemosensitizers in the treatment of high-stage NB.

The oncogenes MYCN and survivin (BIRC5) maintain aggressiveness of diverse cancers including sarcomas. To investigate whether these oncogenes cooperate in initial malignant transformation, we transduced them into Rat-1 fibroblasts. Indeed, survivin enhanced MYCN-driven contact-uninhibited and anchorage-independent growth in vitro. Importantly, upon subcutaneous transplantation into mice, cells overexpressing both instead of either one of the oncogenes generated tumors with shortened latency, marked anaplasia and an increased proliferation-to-apoptosis ratio resulting in accelerated growth. Mechanistically, the increased tumorigenicity was associated with an enhanced Warburg effect and a hypoxia inducible factor 1α linked vascular remodeling. This cooperation between MYCN and survivin may be important in the genesis of several cancers.

Baculoviral inhibitor of apoptosis repeat-containing 5 (BIRC5)/survivin genetic microRNA (miRNA) binding site variants in the 3 untranslated region (3 UTR) are known to be significantly associated with cancer risk. However, the roles of genetic variants in BIRC5/survivin gene 3 UTRs and post-transcriptional regulation have not been elucidated. In the present study, we revealed that rs1042489, rs1042542, rs17882360, rs2239680, rs2661694 and rs4789560 in the BIRC5/survivin 3 UTR have potential miRNA binding sites using bioinformatics analysis. However, only rs1042489 was significantly associated with BIRC5/survivin mRNA expression in lymphoblastoid cell lines (P=0.030); rs1042489 may be a putative variant mediating the post-transcriptional regulation of the target BIRC5/survivin gene. An in-depth understanding of how 3 UTR variants regulate BIRC5/survivin activity is expected to pave the way to targeting the BIRC5/survivin pathway in cancer therapy.