Finally, we showed that cells formed tumors when re-introduced into mice, providing an authentic in vitro-in vivo preclinical model of a subtype of prostate cancer with a hypermutator phenotype and an SPOP mutation.
IQGAP2 (5q13.3) genomic alterations were observed in SPOP-marked PCs and co-occurred with deletion in the RN7SK (16p12.2), SNORA50A (16q21), and SNORA50C (17q23.3) genes; the co-occurrence associated with reductions in DFS (P=4.14e-4).
Importantly, cancer-derived mutations in SPOP or at the Nanog-degron (S68Y) disrupt SPOP-mediated destruction of Nanog, leading to elevated cancer stem cell traits and PrCa progression.
We show that recurrent PC-driver mutations in speckle-type POZ protein (SPOP) stabilize the TRIM24 protein, which promotes proliferation under low androgen conditions.
SPOP was found to be strongly down-regulated in PCa (median=0.24; range=0.04-9.98) and its expression was associated with both, biochemical (p=0.003) and clinical progression free survival (p=0.023), the very low SPOP expression levels being associated to the worst prognosis.
Using next-generation sequencing to analyze the mutations in PC, the main molecular PC subtypes were identified, which depended on the presence of fusion genes and FOXA1, CHD1, and SPOP point mutations; other driver mutations responsible for the progression of PC subclones were also characterized.
Altogether, we have revealed a novel mechanism for SPOP in suppressing prostate cancer and provided evidence to show SPOP has dual functions in prostate cancer and CCRC.
Our data show that resistance to BET inhibitors in SPOP-mutant prostate cancer can be overcome by combination with AKT inhibitors and further support the evaluation of SPOP mutations as biomarkers to guide BET-inhibitor-oriented therapy in patients with prostate cancer.
Our structural and biophysical data confirm the suggested loss-of-function in prostate cancer-associated SPOP mutants and provide mechanistic explanation.
The aim of this study was to compare the frequency of ERG rearrangement, PTEN deletion, SPINK1 overexpression, and SPOP mutation in prostate cancer in African American and Caucasian men.
Class-1 activating mutations originate in early prostate cancer without alterations in ETS or SPOP, selectively recur within the wing-2 region of the DNA-binding forkhead domain, enable enhanced chromatin mobility and binding frequency, and strongly transactivate a luminal androgen-receptor program of prostate oncogenesis.