scholarly journals hASH1 nuclear localization persists in neuroendocrine transdifferentiated prostate cancer cells, even upon reintroduction of androgen

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Jennifer A. Fraser ◽  
Joseph E. Sutton ◽  
Saba Tazayoni ◽  
Isla Bruce ◽  
Amy V. Poole

AbstractNeuroendocrine prostate cancer (NEPC) is thought to arise as prostate adenocarcinoma cells transdifferentiate into neuroendocrine (NE) cells to escape potent anti-androgen therapies however, the exact molecular events accompanying NE transdifferentiation and their plasticity remain poorly defined. Cell fate regulator ASCL1/hASH1’s expression was markedly induced in androgen deprived (AD) LNCaP cells and prominent nuclear localisation accompanied acquisition of the NE-like morphology and expression of NE markers (NSE). By contrast, androgen-insensitive PC3 and DU145 cells displayed clear nuclear hASH1 localisation under control conditions that was unchanged by AD, suggesting AR signalling negatively regulated hASH1 expression and localisation. Synthetic androgen (R1881) prevented NE transdifferentiation of AD LNCaP cells and markedly suppressed expression of key regulators of lineage commitment and neurogenesis (REST and ASCL1/hASH1). Post-AD, NE LNCaP cells rapidly lost NE-like morphology following R1881 treatment, yet ASCL1/hASH1 expression was resistant to R1881 treatment and hASH1 nuclear localisation remained evident in apparently dedifferentiated LNCaP cells. Consequently, NE cells may not fully revert to an epithelial state and retain key NE-like features, suggesting a “hybrid” phenotype. This could fuel greater NE transdifferentiation, therapeutic resistance and NEPC evolution upon subsequent androgen deprivation. Such knowledge could facilitate CRPC tumour stratification and identify targets for more effective NEPC management.

2006 ◽  
Vol 282 (7) ◽  
pp. 4943-4950 ◽  
Author(s):  
Hongzhe Li ◽  
Xiaojian Wang ◽  
Nan Li ◽  
Jianming Qiu ◽  
Yuanyuan Zhang ◽  
...  

The treatment options available for prostate cancer are limited because of its resistance to therapeutic agents. Thus, a better understanding of the underlying mechanisms of the resistance of prostate cancer will facilitate the discovery of more efficient treatment protocols. Human phosphatidylethanolamine-binding protein 4 (hPEBP4) is recently identified by us as an anti-apoptotic molecule and a potential candidate target for breast cancer treatment. Here we found the expression levels of hPEBP4 were positively correlated with the severity of clinical prostate cancer. Furthermore, hPEBP4 was not expressed in TRAIL-sensitive DU145 prostate cancer cells, but was highly expressed in TRAIL-resistant LNCaP cells, which show highly activated Akt. Interestingly, hPEBP4 overexpression in TRAIL-sensitive DU145 cells promoted Akt activation but inhibited ERK1/2 activation. The hPEBP4-overexpressing DU145 cells became resistant to TRAIL-induced apoptosis consequently, which could be reversed by PI3K inhibitors. In contrast, silencing of hPEBP4 in TRAIL-resistant LNCaP cells inhibited Akt activation but increased ERK1/2 activation, resulting in their sensitivity to TRAIL-induced apoptosis that was restored by the MEK1 inhibitor. Therefore, hPEBP4 expression in prostate cancer can activate Akt and deactivate ERK1/2 signaling, leading to TRAIL resistance. We also demonstrated that hPEBP4-mediated resistance to TRAIL-induced apoptosis occurred downstream of caspase-8 and at the level of BID cleavage via the regulation of Akt and ERK pathways, and that hPEBP4-regulated ERK deactivation was upstream of Akt activation in prostate cancer cells. Considering that hPEBP4 confers cellular resistance to TRAIL-induced apoptosis and is abundantly expressed in poorly differentiated prostate cancer, silencing of hPEBP4 suggests a promising approach for prostate cancer treatment.


Cancers ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 578
Author(s):  
Marc Wiesehöfer ◽  
Elena Dilara Czyrnik ◽  
Martin Spahn ◽  
Saskia Ting ◽  
Henning Reis ◽  
...  

Patients with advanced prostate carcinoma are often treated with an androgen deprivation therapy but long-term treatment can result in a metastatic castration-resistant prostate cancer. This is a more aggressive, untreatable tumor recurrence often containing areas of neuroendocrine differentiated prostate cancer cells. Using an in vitro model of NE-like cancer cells, it could previously be shown that neuroendocrine differentiation of LNCaP cells leads to a strong deregulation of mRNA and miRNA expression. We observe elevated RNA and protein levels of AKT Serine/Threonine Kinase 3 (AKT3) in neuroendocrine-like LNCaP cells. We used prostate resections from patients with neuroendocrine prostate cancer to validate these results and detect a co-localization of neuroendocrine marker genes with AKT3. Analysis of downstream target genes FOXO3A and GSK3 strengthens the assumption AKT3 may play a role in neuroendocrine differentiation. Overexpression of AKT3 shows an increased survival rate of LNCaP cells after apoptosis induction, which in turn reflects the significance in vivo or for treatment. Furthermore, miR-17, −20b and −106b, which are decreased in neuroendocrine-like LNCaP cells, negatively regulate AKT3 biosynthesis. Our findings demonstrate AKT3 as a potential therapeutic target and diagnostic tool in advanced neuroendocrine prostate cancer and a new mRNA–miRNA interaction with a potential role in neuroendocrine differentiation of prostate cancer.


2021 ◽  
Vol 14 (2) ◽  
pp. 103
Author(s):  
Zohaib Rana ◽  
Joel D. A. Tyndall ◽  
Muhammad Hanif ◽  
Christian G. Hartinger ◽  
Rhonda J. Rosengren

Androgen receptor (AR)-null prostate tumors have been observed in 11–24% of patients. Histone deacetylases (HDACs) are overexpressed in prostate tumors. Therefore, HDAC inhibitors (Jazz90 and Jazz167) were examined in AR-null prostate cancer cell lines (PC3 and DU145). Both Jazz90 and Jazz167 inhibited the growth of PC3 and DU145 cells. Jazz90 and Jazz167 were more active in PC3 cells and DU145 cells in comparison to normal prostate cells (PNT1A) and showed a 2.45- and 1.30-fold selectivity and higher cytotoxicity toward DU145 cells, respectively. Jazz90 and Jazz167 reduced HDAC activity by ~60% at 50 nM in PC3 lysates. At 4 μM, Jazz90 and Jazz167 increased acetylation in PC3 cells by 6- to 8-fold. Flow cytometry studies on the cell phase distribution demonstrated that Jazz90 causes a G0/G1 arrest in AR-null cells, whereas Jazz167 leads to a G0/G1 arrest in DU145 cells. However, apoptosis only occurred at a maximum of 7% of the total cell population following compound treatments in PC3 and DU145 cells. There was a reduction in cyclin D1 and no significant changes in bcl-2 in DU145 and PC3 cells. Overall, the results showed that Jazz90 and Jazz167 function as cytostatic HDAC inhibitors in AR-null prostate cancer cells.


2008 ◽  
Vol 283 (28) ◽  
pp. 19872
Author(s):  
Florian Gackière ◽  
Gabriel Bidaux ◽  
Philippe Delcourt ◽  
Fabien Van Coppenolle ◽  
Maria Katsogiannou ◽  
...  

2020 ◽  
Vol 19 ◽  
pp. 153303382094806
Author(s):  
Guangxing Tan ◽  
Lin Jiang ◽  
Gangqin Li ◽  
Kuan Bai

Objective: To explore the effect and the related mechanism of STAT3 inhibitor AG-490 on inhibiting the proliferation of prostate cancer cells. Methods: PC3 cells and DU145 cells were cultured stably and treated with AG-490 to detect the changes in the activity of PC3 cells and DU145 cells. Thirty 6-8 weeks male BALB/c nude mouse were randomly divided into a control group, a DMSO group, and an AG-490 group to detect differences in various indexes . Results: The overexpression of miR-503-5p depends on the activation of STAT3. After treatment with AG-490, The proliferation and invasion of PC3 cells and DU145 cells and the expression of miR-503-5p were all reduced. Luciferase reporter assay demonstrated that the target proteins of miR-503-5p include PDCD4, TIMP-3, and PTEN. After treatment with AG-490, the expression of PDCD4, TIMP-3, and PTEN in cells was significantly up-regulated. IL-6-induced overexpression of miR-503-5p and restored the expression of STAT3, demonstrating the correlation between STAT3 and miR-503-5p. AG-490 can inhibit tumor growth and induce tumor cell apoptosis in the PC3 BALB/c nude mouse xenograft model. Western blotting and immunohistochemical staining showed that the expression levels of STAT3, Ki67, Bcl-2 and MMP-2 in the AG-490 group were significantly reduced, and the expression of PDCD4, TIMP-3 and PTEN increased. Conclusion: AG-490 can inhibit the growth of prostate cancer cells in a miR-503-5p-dependent manner by targeting STAT3. AG-490 is expected to become a new candidate drug for the treatment of prostate cancer.


2019 ◽  
Vol 2019 ◽  
pp. 1-10 ◽  
Author(s):  
Peng Xie ◽  
Hongliang Yu ◽  
Feijiang Wang ◽  
Feng Yan ◽  
Xia He

Introduction. Radiotherapy is the mainstay in the treatment of prostate cancer. However, significant radioresistance of castration-resistant prostate cancer (CRPC) cells constitutes a main obstacle in the treatment of this disease. By using bioinformatic data mining methods, LOXL2 was found to be upregulated in both androgen-independent prostate cancer cell lines and radioresistant tumor samples collected from patients with prostate cancer. We speculate that LOXL2 may play an important role in the radioresistance of CRPC cells. Methods. The effect of LOXL2 knockdown on the radiosensitivity of androgen-independent prostate cancer cells lines was measured by the clonogenic assay and xenograft tumor experiments under in vitro and in vivo conditions, respectively. In studies on the mechanism, we focused on the EMT phenotype changes and cell apoptosis changes induced by LOXL2 knockdown in DU145 cells. The protein levels of three EMT biomarkers, namely, E-cadherin, vimentin, and N-cadherin, were measured by western blotting and immunohistochemical staining. Cell apoptosis after irradiation was measured by flow cytometry and caspase-3 activity assay. Salvage experiment was also conducted to confirm the possible role of EMT in the radiosensitization effect of LOXL2 knockdown in CRPC cells. Results. LOXL2 knockdown in CRPC cells enhanced cellular radiosensitivity under both in vitro and in vivo conditions. A significant reversal of EMT was observed in LOXL2-silenced DU145 cells. Cell apoptosis after irradiation was significantly enhanced by LOXL2 knockdown in DU145 cells. Results from the salvage experiment confirmed the key role of EMT process reversal in the radiosensitization effect of LOXL2 knockdown in DU145 cells. Conclusions. LOXL2 plays an important role in the development of cellular radioresistance in CRPC cells. Targeting LOXL2 may be a rational avenue to overcome radioresistance in CRPC cells. A LOXL2-targeting strategy for CRPC treatment warrants detailed investigation in the future.


2012 ◽  
Vol 109 (2) ◽  
pp. 210-222 ◽  
Author(s):  
So Young Park ◽  
Chu Won Nho ◽  
Dae Young Kwon ◽  
Young-Hee Kang ◽  
Ki Won Lee ◽  
...  

Maslinic acid is found in various natural sources, most notably in pomace olive oil, and exerts pro-apoptotic activities in various cancer cells in vitro. In the present study, DU145 human prostate cancer cells were cultured with 0–25 μm-maslinic acid to examine the effects of maslinic acid on the metastatic capacity of prostate cancer cells. Maslinic acid significantly (P <0·05) inhibited the basal and epidermal growth factor (EGF)-induced migration (27–64 %), invasion (23–60 %) and adhesion (8–40 %) of DU145 cells. Maslinic acid significantly (P <0·05) down-regulated both basal and EGF-stimulated secretion of matrix metalloproteinase (MMP)-9 (25–67 %), MMP-2 (50–86 %), urokinase-type plasminogen activator (uPA, about 100 %), vascular endothelial growth factor (VEGF, 98–100 %) and tissue inhibitors of metalloproteinases (TIMP)-1, as well as expression of uPA receptor (uPAR), intercellular adhesion molecules (22–33 %), vascular cell adhesion molecules (23–46 %) and E-cadherin, whereas it increased TIMP-2 secretion. Maslinic acid dramatically reduced the levels of hypoxia-inducible factor-1α (HIF-1α) protein and mRNA; the reduction was accompanied by reduced stability, nuclear levels and transcriptional activity of HIF-1α. The levels of phospho-Akt and phospho-extracellular signal-related kinase (ERK) were reduced in cells treated with maslinic acid, and the phosphoinositide 3-kinase inhibitor LY294002 and the mitogen-activated protein kinase kinase inhibitor PD98059 reduced HIF-1α levels and VEGF secretion. The results show that maslinic acid markedly inhibited the migration, invasion and adhesion of DU145 prostate cancer cells. Suppressing HIF-1α activation by inhibiting Akt and ERK activation may be part of the mechanism by which maslinic acid inhibited uPAR, E-cadherin, VEGF and MMP expression in DU145 cells.


Endocrinology ◽  
2006 ◽  
Vol 147 (10) ◽  
pp. 4883-4892 ◽  
Author(s):  
Rishu Guo ◽  
Elizabeth A. Kasbohm ◽  
Puneeta Arora ◽  
Christopher J. Sample ◽  
Babak Baban ◽  
...  

The bioactive phospholipid lysophosphatidic acid (LPA) promotes cell proliferation, survival, and migration by acting on cognate G protein-coupled receptors named LPA1, LPA2, and LPA3. We profiled gene expression of LPA receptors in androgen-dependent and androgen-insensitive prostate cancer cells and found that LPA1 gene is differentially expressed in androgen-insensitive and LPA-responsive but not androgen-dependent and LPA-resistant cells. In human prostate specimens, expression of LPA1 gene was significantly higher in the cancer compared with the benign tissues. The androgen-dependent LNCaP cells do not express LPA1 and do not proliferate in response to LPA stimulation, implying LPA1 transduces cell growth signals. Accordingly, stable expression of LPA1 in LNCaP cells rendered them responsive to LPA-induced cell proliferation and decreased their doubling time in serum. Implantation of LNCaP-LPA1 cells resulted in increased rate of tumor growth in animals compared with those tumors that developed from the wild-type cells. Growth of LNCaP cells depends on androgen receptor activation, and we show that LPA1 transduces Gαi-dependent signals to promote nuclear localization of androgen receptor and cell proliferation. In addition, treatment with bicalutamide inhibited LPA-induced cell cycle progression and proliferation of LNCaP-LPA1 cells. These results suggest the possible utility of LPA1 as a drug target to interfere with progression of prostate cancer.


2007 ◽  
Vol 25 (18_suppl) ◽  
pp. 10566-10566
Author(s):  
R. Singal ◽  
K. Ramachandran ◽  
G. Gopisetty ◽  
L. Navarro ◽  
E. Gordian ◽  
...  

10566 Background: Defects in the apoptotic pathway contribute to uncontrolled cell proliferation of cancer cells and confer resistance to chemotherapeutic drugs. Understanding the mechanisms of deregulation of apoptosis related genes would enable targeted treatment methods to improve the efficacy of chemotherapy. Growth Arrest and DNA Damage inducible, alpha (GADD45a) mediates cytotoxicity of docetaxel chemotherapy. We examined the mechanism of regulation of GADD45a in prostate cancer cells and the effect of its upregulation on sensitivity to docetaxel chemotherapy. Methods: Levels of GADD45a in Du145, LNCaP and PC3 were analyzed by real time reverse transcriptase PCR and western blotting. DNA methylation was studied by bisulfite sequencing. Chromatin immunoprecipitation was used to study interaction of methyl binding proteins to GADD45 5’ sequence. Cytotoxicity after drug treatment was measured by MTT cell proliferation assay. Apoptosis assays were done by Annexin V/propidium iodide staining followed by flow cytometry. Results: Levels of expression of GADD45a in Du145 and LNCaP cells were lower than that in PC3. A 4 CpG region upstream of the proximal promoter region was methylated in Du145 and LNCaP cells. Methylation was reversed by treatment of Du145 and LNCaP cells with DNA methyl transferase (DNMT) inhibitors such as 5- Azacytidine or 5- Aza deoxycytidine leading to reactivation of GADD45a expression in these cells. This region was also frequently methylated in prostate cancer tissues. Methyl binding protein, MeCP2 was associated with the methylated 4 CpGs in Du145 and knock down of MeCP2 by transfection of MeCP2 siRNA vector in Du145 cells (Du145-MeCP2-ve) led to increased expression of GADD45a, without affecting the methylation status of the gene. Enhanced sensitivity to docetaxel was observed by upregulation of GADD45a in Du145 cells by (a) recombinant expression of GADD45a (b) downregulation of MeCP2 and (c) pretreatment with 5-Azacytidine. Conclusions: GADD45a is frequently deregulated in prostate cancer by methylation of 5’ 4 CpG region and is a potential therapeutic target for treatment of prostate cancer. [Table: see text]


Endocrinology ◽  
2000 ◽  
Vol 141 (1) ◽  
pp. 10-17 ◽  
Author(s):  
Sarah E. Blutt ◽  
Timothy J. McDonnell ◽  
Tara C. Polek ◽  
Nancy L. Weigel

Abstract While the role of vitamin D in bone and mineral metabolism has been investigated extensively, the role of the vitamin D receptor in other tissues is less well understood. 1,25-dihydroxyvitamin D3 (calcitriol) can act as a differentiating agent in normal tissues and can inhibit the growth of many cancer cell lines including LNCaP prostate cancer cells. We have shown previously that calcitriol causes LNCaP cell accumulation in the G0/G1 phase of the cell cycle. In this study, we demonstrate that calcitriol also induces apoptosis of LNCaP cells. The calcitriol-induced apoptosis is accompanied by a down-regulation of Bcl-2 and Bcl-XL proteins, both of which protect cells from undergoing apoptosis. Other proteins important in apoptotic control, Bax, Mcl-1, and Bcl-Xs, are unaffected by calcitriol treatment. We find that overexpression of Bcl-2 blocks calcitriol-induced apoptosis and reduces, but does not eliminate, calcitriol-induced growth inhibition. We conclude that both regulation of cell cycle and the apoptotic pathway are involved in calcitriol action in prostate cancer cells.


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