ABSTRACT
Objective:To explore the efficacy and mechanism of Guben Qingyuan prescription combined with androgen deprivation therapy （ADT） in the treatment of castration-resistant prostate cancer （CRPC）. Method:A CRPC-bearing mouse model was established. When the tumor volume reached about 100 mm<sup>3</sup>， 50 CRPC-bearing BALB/c nude mice were randomly divided into the model group， ADT group， and ADT+low-， medium-， high-dose Guben Qingyuan prescription groups， with 10 mice in each group. After grouping， it was ensured that there was no statistically significant difference in tumor volume between groups. The mice in the model group was treated with the same amount of normal saline （10 mL·kg<sup>-1</sup>） by gavage， twice a day， while those in the other groups were provided with bicalutamide （5 mg·kg<sup>-1</sup>） for intragastric administration， once a day， and then with goserelin （0.36 mg·kg<sup>-1</sup>） for intraperitoneal injection on the 10th day. On the basis of ADT， the ones in the ADT+Guben Qingyuan prescription groups further received Guben Qingyuan prescription at the low （2.5 g·kg<sup>-1</sup>）， medium （25 g·kg<sup>-1</sup>）， and high doses （50 g·kg<sup>-1</sup>） by gavage， twice a day. After 25 days of continuous administration， the tumor tissue was harvested for recording the tumor growth and calculating the tumor inhibition rate. The mRNA and protein expression levels of androgen receptor （AR）， androgen receptor splice variant-7 （AR-V7）， and prostate-specific antigen （PSA） were detected by real-time polymerase chain reaction （Real-time PCR） and Western blot assay. Result:The tumor inhibition rates of the ADT+low-， medium-， and high-dose Guben Qingyuan prescription groups were 27.95%， 46.71%， and 44.46%， respectively， and the inhibition rates in the ADT+medium- and high-dose Guben Qingyuan prescription groups were significantly increased as compared with that in the ADT group （<italic>P</italic><0.05）. As revealed by comparison with the ADT group， Guben Qingyuan prescription at the medium and high doses significantly down-regulated the mRNA and protein expression levels of AR， AR-V7， and PSA （<italic>P</italic><0.05）. Conclusion:Guben Qingyuan prescription combined with ADT is efficient in controlling the tumor growth in CRPC-bearing mice， which is related to the regulation of AR/AR-V7 signaling pathway.
ABSTRACT
Objective To solve the problem of castration resistant prostate cancer (castrationresistant prostate cancer,CRPC) the problem of drug resistance by studing the expression of the CUDC-101 inhibitor of castration resistant prostate cancer androgen receptor splice variant 7.Methods In this study,the expression of AR-V7 protein in prostate cancer cell lines PC-3,VCaP,22Rv1,LNCap was detected by imnmunoblotting between April 2015 and April 2016,and the highest expression level of cell lines was selected follow-up experiments.Through the cell proliferation and activity experiments,the epigenetic inhibitors:histone deacetylase inhibitor CUDC-101,histone methylation inhibitor DZNeP,DNA methylation inhibitor gemcitabine,histone acetyltransferase inhibitor MG149 to select an inhibitor that reduces the expression of AR-V7 protein in CRPC cells.22Rv1 cells were treated with 30 nmol and 300 nmol of CUDC101 and 1,10 and 20 μmol of Enzalutamide (MDV3100),respectively,and their inhibitory effects on the growth of 22Rv1 cells were examined.Results The results of immunoblotting showed that AR-V7 protein was only expressed in CRPC cell line 22Rv1 and negative in non-CRPC cell line.The expression of AR-V7 in 22Rv1 cells treated with CUDC-101 was significantly lower than that of negative control.While other inhibitors had no effect on the expression of AR-V7.In the cell proliferation and activity assay,the inhibitory rates of 30 nmol CUDC-101 and 1,10 and 20 μmol MDV3100 were 10％,35％ and 45％,respectively,higher than that of MDV3100 alone.28％ and 42％,the difference was statistically significant (P ＜ 0.05).The inhibitory rates of 300 nmol CUDC-101 and MDV3100 were 30％,60％ and 65％,respectively,which were significantly higher than those of MDV3100 alone (P ＜ 0.05).Conclusions CUDC-101 can inhibit the castration resistant prostate cancer androgen receptor splice variant 7 expression,and solved the resistance problem of CRPC.
ABSTRACT
Prostate cancer cells demonstrate a remarkable "addiction" to androgen receptor (AR) signaling in all stages of disease progression. As such, suppression of AR signaling remains the therapeutic goal in systemic treatment of prostate cancer. A number of molecular alterations arise in patients treated with AR-directed therapies. These molecular alterations may indicate the emergence of treatment resistance and may be targeted for the development of novel agents for prostate cancer. The presence of functional androgen receptor splice variants may represent a potential explanation for resistance to abiraterone and enzalutamide, newer AR-directed agents developed to treat metastatic castration-resistant prostate cancer (mCRPC). In the last 8 years, many androgen receptor splice variants have been identified and characterized. Among these, androgen receptor splice variant-7 (AR-V7) has been investigated extensively. In AR-V7, the entire COOH-terminal ligand-binding domain of the canonical AR is truncated and replaced with a variant-specific peptide of 16 amino acids. Functionally, AR-V7 is capable of mediating constitutive nuclear localization and androgen receptor signaling in the absence of androgens, or in the presence of enzalutamide. In this review, we will focus on clinical translational studies involving detection/measurement of AR-V7. Methods have been developed to detect AR-V7 in clinical mCRPC specimens. AR-V7 can be reliably measured in both tissue and circulating tumor cells derived from mCRPC patients, making it possible to conduct both cross-sectional and longitudinal clinical correlative studies. Current evidence derived from studies focusing on detection of AR-V7 in mCRPC support its potential clinical utility as a treatment selection marker.