scholarly journals Targeting ADT-Induced Activation of the E3 Ubiquitin Ligase Siah2 to Delay the Occurrence of Castration-Resistant Prostate Cancer

2021 ◽  
Vol 11 ◽  
Author(s):  
Tingmang Yan ◽  
Dapeng Zhou ◽  
Youwei Shi ◽  
Di Cui ◽  
Juntao Jiang ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Protein Expression ◽  
Ubiquitin Ligase ◽  
E3 Ubiquitin Ligase ◽  
E3 Ligase ◽  
Castration Resistant Prostate Cancer ◽  
Vitamin K3 ◽  
Protein Levels ◽  
Castration Resistant

Siah2 is an E3 ubiquitin ligase that targets androgen receptor (AR) and plays an important role in the development of castration-resistant prostate cancer (CRPC). However, the regulation of Siah2 in prostate cancer (PCa) is largely unknown. In this study, we used AR-dependent and -independent cells lines to investigate the cellular roles of AR and androgen deprivation therapy (ADT) on Siah2 protein levels and E3 ligase activity using Western blotting and co-immunoprecipitation. We also validated our findings using patient samples taken before and after ADT. Finally, we used xenograft tumor models to test the effects of ADT combined with vitamin K3 (Vit K3) on tumor growth in vivo. Our results showed that AR stabilizes Siah2 protein by attenuating its self-ubiquitination and auto-degradation, likely by blocking its E3 ubiquitin ligase activity. Conversely, ADT decreased Siah2 protein expression but enhanced its E3 ligase activity in PCa cells. Notably, the findings that ADT decreasing Siah2 protein expression were verified in a series of paired PCa samples from the same patient. Additionally, we found that ADT-induced Siah2 activation could be abolished by Vit K3. Strikingly, ADT combined with Vit K3 treatment delayed the occurrence of CRPC and dramatically inhibited the growth of tumor xenografts compared with ADT treatment alone. AR is an inhibitor of Siah2 in PCa, and ADT leads to the continuous activation of Siah2, which may contribute to CRPC. Finally, ADT+Vit K3 may be a potential approach to delay the occurrence of CRPC.

scholarly journals Crosstalk of NF-κB/P65 and LncRNA HOTAIR-Mediated Repression of MUC1 Expression Contribute to Synergistic Inhibition of Castration-Resistant Prostate Cancer by Polyphyllin 1–Enzalutamide Combination Treatment

2018 ◽  
Vol 47 (2) ◽  
pp. 759-773 ◽  
Author(s):  
SongTao Xiang ◽  
PeiLiang Zou ◽  
JingJing Wu ◽  
Fang Zheng ◽  
Qing Tang ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Cell Cycle ◽  
Protein Expression ◽  
Cell Cycle Distribution ◽  
Muc1 Expression ◽  
Castration Resistant Prostate Cancer ◽  
Antitumor Effects ◽  
Castration Resistant ◽  
Muc1 Gene

Background/Aims: Polyphyllin I (PPI), one of the steroidal saponins in Paris polyphylla, reportedly exhibits antitumor effects. However, the detailed mechanism underlying PPI, particularly in enhancing the effect of the androgen receptor inhibitor enzalutamide in controlling castration-resistant prostate cancer (CRPC) has not been explored. Methods: Cell viability and cell cycle distribution were measured using 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) and flow cytometry assays, respectively. Long non-coding RNA (lncRNA) HOX transcript antisense RNA (HOTAIR) expression was measured by quantitative real time-PCR (qRT-PCR). Western blot analysis was performed to determine the protein expression levels of MUC1, p65, and p50. Silencing of HOTAIR was evaluated using the siRNA procedure. The promoter activity of the MUC1 gene was determined using Secrete-Pair Dual Luminescence Assay Kit. Exogenous expression of HOTAIR, p65, and MUC1 was conducted by transient transfection assay. A xenograft tumor model in nude mice was used to further evaluate the effect of the combination of PPI and enzalutamide in vivo. Results: We showed that PPI significantly inhibited growth and induced cell cycle arrest in CRPC cells. PPI also decreased p65 and MUC1 protein expression and reduced HOTAIR expression. Exogenously expressed p65 resisted the PPI-inhibited expression of HOTAIR, whereas silenced HOTAIR reduced MUC1 protein but exerted no effect on the expression of p65 and p50 proteins. Conversely, exogenously expressed HOTAIR resisted the PPI-inhibited MUC1 protein expression, and excessive expression of MUC1 antagonized the PPI-inhibited cell growth. Notably, PPI combined with enzalutamide exerted a synergistic effect. Consistent with this finding, PPI inhibited tumor growth, HOTAIR expression, as well as p65 and MUC1 protein expressions in vivo. Conclusions: Our results indicate that PPI inhibits the growth of CRPC cells by inhibiting p65 protein and concomitantly reducing HOTAIR expression, thereby suppressing MUC1 gene expression. The novel regulatory interaction of p65 and HOTAIR converge in the inhibition of MUC1 expression and overall PPI response. The combination of PPI and enzalutamide exhibits synergy. This study reveals a novel mechanism underlying the synergistic inhibitory effect of PPI and enzalutamide on the growth of CRPC cells.

scholarly journals The Steroidogenic Enzyme AKR1C3 Regulates Stability of the Ubiquitin Ligase Siah2 in Prostate Cancer Cells

2015 ◽  
Vol 290 (34) ◽  
pp. 20865-20879 ◽  
Author(s):  
Lingling Fan ◽  
Guihong Peng ◽  
Arif Hussain ◽  
Ladan Fazli ◽  
Emma Guns ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Cell Growth ◽  
Cancer Cells ◽  
Ubiquitin Ligase ◽  
Castration Resistant Prostate Cancer ◽  
Prostate Cancer Cells ◽  
Cancer Cell Growth ◽  
Protein Levels ◽  
Castration Resistant

Re-activation of androgen receptor (AR) activity is the main driver for development of castration-resistant prostate cancer. We previously reported that the ubiquitin ligase Siah2 enhanced AR transcriptional activity and prostate cancer cell growth. Among the genes we found to be regulated by Siah2 was AKR1C3, which encodes a key androgen biosynthetic enzyme implicated in castration-resistant prostate cancer development. Here, we found that Siah2 inhibition in CWR22Rv1 prostate cancer cells decreased AKR1C3 expression as well as intracellular androgen levels, concomitant with inhibition of cell growth in vitro and in orthotopic prostate tumors. Re-expression of either wild-type or catalytically inactive forms of AKR1C3 partially rescued AR activity and growth defects in Siah2 knockdown cells, suggesting a nonenzymatic role for AKR1C3 in these outcomes. Unexpectedly, AKR1C3 re-expression in Siah2 knockdown cells elevated Siah2 protein levels, whereas AKR1C3 knockdown had the opposite effect. We further found that AKR1C3 can bind Siah2 and inhibit its self-ubiquitination and degradation, thereby increasing Siah2 protein levels. We observed parallel expression of Siah2 and AKR1C3 in human prostate cancer tissues. Collectively, our findings identify a new role for AKR1C3 in regulating Siah2 stability and thus enhancing Siah2-dependent regulation of AR activity in prostate cancer cells.

scholarly journals Humanization, Radiolabeling and Biodistribution Studies of an IgG1-Type Antibody Targeting Uncomplexed PSA for Theranostic Applications

2021 ◽  
Vol 14 (12) ◽  
pp. 1251
Author(s):  
Joanna Strand ◽  
Kjell Sjöström ◽  
Urpo J. Lamminmaki ◽  
Oskar Vilhelmsson Timmermand ◽  
Sven-Erik Strand ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Specific Binding ◽  
Hek293 Cells ◽  
Castration Resistant Prostate Cancer ◽  
Castration Resistant ◽  
Biodistribution Studies ◽  
Indium 111 ◽  
Hormone Refractory ◽  
Theranostic Applications

Metastatic castration-resistant prostate cancer is today incurable. Conventional imaging methods have limited detection, affecting their ability to give an accurate outcome prognosis, and current therapies for metastatic prostate cancer are insufficient. This inevitably leads to patients relapsing with castration-resistant prostate cancer. Targeting prostate-specific antigens whose expression is closely linked to the activity in the androgen receptor pathway, and thus the pathogenesis of prostate cancer, is a possible way to increase specificity and reduce off-target effects. We have humanized and evaluated radioimmunoconjugates of a previously murine antibody, m5A10, targeting PSA intended for theranostics of hormone-refractory prostate cancer. The humanized antibody h5A10 was expressed in mammalian HEK293 cells transfected with the nucleotide sequences for the heavy and light chains of the antibody. Cell culture medium was filtered and purified by Protein G chromatography, and the buffer was changed to PBS pH 7.4 by dialysis. Murine and humanized 5A10 were conjugated with p-SCN-Bn-CHX-A”-DTPA. Surface plasmon resonance was used to characterize the binding to PSA of the immunoconjugates. Immunoconjugates were labeled with either indium-111 or lutetium-177. Biodistribution studies of murine and humanized 5A10 were performed in mice with LNCaP xenografts. 5A10 was successfully humanized, and in vivo targeting showed specific binding in xenografts. The results thus give an excellent platform for further theranostic development of humanized 5A10 for clinical applications.

scholarly journals MicroRNA-1205 Regulation of FRYL in Prostate Cancer

2021 ◽  
Vol 9 ◽  
Author(s):  
Michelle Naidoo ◽  
Fayola Levine ◽  
Tamara Gillot ◽  
Akintunde T. Orunmuyi ◽  
E. Oluwabunmi Olapade-Olaopa ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Neuroendocrine Differentiation ◽  
Castration Resistant Prostate Cancer ◽  
Chromosomal Locus ◽  
Protein Coding ◽  
Castration Resistant ◽  
Dendritic Branching ◽  
Very High

High mortality rates of prostate cancer (PCa) are associated with metastatic castration-resistant prostate cancer (CRPC) due to the maintenance of androgen receptor (AR) signaling despite androgen deprivation therapies (ADTs). The 8q24 chromosomal locus is a region of very high PCa susceptibility that carries genetic variants associated with high risk of PCa incidence. This region also carries frequent amplifications of the PVT1 gene, a non-protein coding gene that encodes a cluster of microRNAs including, microRNA-1205 (miR-1205), which are largely understudied. Herein, we demonstrate that miR-1205 is underexpressed in PCa cells and tissues and suppresses CRPC tumors in vivo. To characterize the molecular pathway, we identified and validated fry-like (FRYL) as a direct molecular target of miR-1205 and observed its overexpression in PCa cells and tissues. FRYL is predicted to regulate dendritic branching, which led to the investigation of FRYL in neuroendocrine PCa (NEPC). Resistance toward ADT leads to the progression of treatment related NEPC often characterized by PCa neuroendocrine differentiation (NED), however, this mechanism is poorly understood. Underexpression of miR-1205 is observed when NED is induced in vitro and inhibition of miR-1205 leads to increased expression of NED markers. However, while FRYL is overexpressed during NED, FRYL knockdown did not reduce NED, therefore revealing that miR-1205 induces NED independently of FRYL.

scholarly journals Anti-Proliferative, Anti-Angiogenic and Safety Profiles of Novel HDAC Inhibitors for the Treatment of Metastatic Castration-Resistant Prostate Cancer

2021 ◽  
Vol 14 (10) ◽  
pp. 1020
Author(s):  
Zohaib Rana ◽  
Sarah Diermeier ◽  
Fearghal P. Walsh ◽  
Muhammad Hanif ◽  
Christian G. Hartinger ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Histone Deacetylases ◽  
Hdac Inhibitors ◽  
Tube Formation ◽  
In Vivo Studies ◽  
Efficacy And Safety ◽  
Castration Resistant Prostate Cancer ◽  
Castration Resistant ◽  
Pc3 Cells

Metastatic castration-resistant prostate cancer (CRPC) has a five-year survival rate of 28%. As histone deacetylases (HDACs) are overexpressed in CRPC, the HDAC inhibitor suberoylanilide hydroxamic acid (SAHA) was trialled in CRPC patients but found to be toxic and inefficacious. Previously, we showed that novel HDAC inhibitors (Jazz90 (N1-hydroxy-N8-(4-(pyridine-2-carbothioamido)phenyl)octanediamide) and Jazz167 ([chlorido(η5-pentamethylcyclopentadieny[1–4](N1-hydroxy-N8-(4-(pyridine-2-carbothioamido-κ2N,S)phenyl)octanediamide)rhodium(III)] chloride) had a higher cancer-to-normal-cell selectivity and superior anti-angiogenic effects in CRPC (PC3) cells than SAHA. Thus, this study aimed to further investigate the efficacy and toxicity of these compounds. HUVEC tube formation assays revealed that Jazz90 and Jazz167 significantly reduced meshes and segment lengths in the range of 55–88 and 43–64%, respectively. However, Jazz90 and Jazz167 did not affect the expression of epithelial-to-mesenchymal transitioning markers E-cadherin and vimentin. Jazz90 and Jazz167 significantly inhibited the growth of PC3 and DU145 spheroids and reduced PC3 spheroid branching. Jazz90 and Jazz167 (25, 50 and 75 mg/kg/day orally for 21 days) were non-toxic in male BALB/c mice. The efficacy and safety of these compounds demonstrate their potential for further in vivo studies in CRPC models.

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