Vav3, a Rho GTPase Guanine Nucleotide Exchange Factor, Increases during Progression to Androgen Independence in Prostate Cancer Cells and Potentiates Androgen Receptor Transcriptional Activity
The progression of prostate cancer from androgen dependence to androgen independence is often accompanied by enhanced androgen receptor (AR) transcriptional activity. We observed a marked increase in the expression of Vav3, a Rho GTPase guanine nucleotide exchange factor (GEF), during the progression of human prostate cancer LNCaP cells to the androgen-independent derivative, LNCaP-R1. GEFs activate Rho family GTPases by promoting the exchange of GDP for GTP. Reporter gene assays showed that Vav3 potentiated AR transcriptional activity, and knock down of Vav3 resulted in decreased AR transactivation. Vav3 also increased androgen-induced levels of prostate-specific antigen mRNA. Furthermore, Vav3 enhanced AR activity at subnanomolar concentrations of androgen. This finding is particularly relevant because low androgen levels may be present in prostate tissue of patients undergoing androgen deprivation therapy. Enhancement of AR activity by Vav3 required amino terminal activation function 1 (AF1) of AR; however, Vav3 did not interact with AR or increase AR levels. Neither GEF function nor the C-terminal domains of Vav3 were required for Vav3-mediated enhancement of AR activity; however, the pleckstrin homology domain was obligatory. These data show that Vav3 levels rise during progression to androgen independence and support continued AR signaling (even under conditions of low androgen) by a novel GEF-independent cross-talk mechanism.
This research output has an Altmetric Attention Score of 3. This is our high-level measure of the quality and quantity of online attention that it has received. This Attention Score, as well as the ranking and number of research outputs shown below, was calculated when the research output was last mentioned on 14 July 2018.
All research outputs
#12,345,312
of 34,365,356 outputs
Outputs from Endocrinology
#5,552
of 14,818 outputs
Outputs of similar age
#76,772
of 236,193 outputs
Outputs of similar age from Endocrinology
#41
of 89 outputs
Altmetric has tracked 34,365,356 research outputs across all sources so far. This one is in the 38th percentile – i.e., 38% of other outputs scored the same or lower than it.
So far Altmetric has tracked 14,818 research outputs from this source. They typically receive a little more attention than average, with a mean Attention Score of 5.9. This one is in the 19th percentile – i.e., 19% of its peers scored the same or lower than it.
Older research outputs will score higher simply because they've had more time to accumulate mentions. To account for age we can compare this Altmetric Attention Score to the 236,193 tracked outputs that were published within six weeks on either side of this one in any source. This one is in the 11th percentile – i.e., 11% of its contemporaries scored the same or lower than it.
We're also able to compare this research output to 89 others from the same source and published within six weeks on either side of this one. This one is in the 12th percentile – i.e., 12% of its contemporaries scored the same or lower than it.
