scholarly journals Inactivation of Id-1 in prostate cancer cells: A potential therapeutic target in inducing chemosensitization to taxol through activation of JNK pathway

2005 ◽  
Vol 118 (8) ◽  
pp. 2072-2081 ◽  
Author(s):  
Xiaomeng Zhang ◽  
Ming-Tat Ling ◽  
Xianghong Wang ◽  
Y.C. Wong
Keyword(s):  
Prostate Cancer ◽  
Cancer Cells ◽  
Therapeutic Target ◽  
Prostate Cancer Cells ◽  
Potential Therapeutic Target ◽  
Jnk Pathway

Role of GADD45α as a potential therapeutic target for prostate cancer

2007 ◽  
Vol 25 (18_suppl) ◽  
pp. 10566-10566
Author(s):  
R. Singal ◽  
K. Ramachandran ◽  
G. Gopisetty ◽  
L. Navarro ◽  
E. Gordian ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Cell Proliferation ◽  
Cancer Cells ◽  
Therapeutic Target ◽  
Recombinant Expression ◽  
Proximal Promoter ◽  
Lncap Cells ◽  
Potential Therapeutic Target ◽  
Du145 Cells ◽  
Docetaxel Chemotherapy

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]

scholarly journals Upregulation of pERK and c-JUN by γ-tocotrienol and not α-tocopherol are essential to the differential effect on apoptosis in prostate cancer cells.

2020 ◽  
Author(s):  
Christine Moore ◽  
Victoria Palau ◽  
Rashid Mahboob ◽  
Janet Lightner ◽  
William Stone ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Cancer Cells ◽  
Prostate Cancer Cells ◽  
Cytotoxic Effects ◽  
Jnk Pathway ◽  
Androgen Sensitivity ◽  
Apoptotic Effect ◽  
Select Trial

Abstract Background: α-tocopherol (AT) and γ-tocotrienol (GT3) are vitamin E isoforms considered to have potential chemopreventive properties. AT has been widely studied in vitro and in clinical trials with mixed results. The latest clinical study (SELECT trial) tested AT in prostate cancer patients, determined that AT provided no benefit, and could promote cancer. Conversely, GT3 has shown antineoplastic properties in several in vitro studies, with no clinical studies published to date. GT3 causes apoptosis via upregulation of the JNK pathway; however, inhibition results in a partial block of cell death. We compared side by side the mechanistic differences in these cells in response to AT and GT3.Methods: The effects of GT3 and AT were studied on androgen sensitive LNCaP and androgen independent PC-3 prostate cancer cells. Their cytotoxic effects were analyzed via MTT and confirmed by metabolic assays measuring ATP. Cellular pathways were studied by immunoblot. Quantitative analysis and the determination of relationships between cell signaling events were analyzed for both agents tested. Non-cancerous prostate RWPE-1 cells were also included as a control. Results: The RAF/RAS/ERK pathway was significantly activated by GT3 in LNCaP and PC-3 cells but not by AT. This activation is essential for the apoptotic affect by GT3 as demonstrated the complete inhibition of apoptosis by MEK1 inhibitor U0126. Phospho-c-JUN was upregulated by GT3 but not AT. No changes were observed on AKT for either agent, and no release of cytochrome c into the cytoplasm was detected. Caspases 9 and 3 were efficiently activated by GT3 on both cell lines irrespective of androgen sensitivity, but not in cells dosed with AT. Cell viability of non-cancerous RWPE-1 cells was affected neither by GT3 nor AT. Conclusions: c-JUN is a recognized master regulator of apoptosis as shown previously in prostate cancer. However, the mechanism of action of GT3 in these cells also include a significant activation of ERK which is essential for the apoptotic effect of GT3. The activation of both, ERK and c-JUN, is required for apoptosis and may suggest a relevant step in ensuring circumvention of mechanisms of resistance related to the constitutive activation of MEK1.

scholarly journals LanCL1 protects prostate cancer cells from oxidative stress via suppression of JNK pathway

2018 ◽  
Vol 9 (2) ◽  
Author(s):  
Jianqing Wang ◽  
Qianyi Xiao ◽  
Xu Chen ◽  
Shijun Tong ◽  
Jianliang Sun ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Prostate Cancer ◽  
Cancer Cells ◽  
Prostate Cancer Cells ◽  
Jnk Pathway

scholarly journals Targeting the USP1 dependent KDM4A protein stability as a potential prostate cancer therapy

2019 ◽  
Author(s):  
Shu-Zhong Cui ◽  
Ling-Ling Fan ◽  
You-Qiang Li ◽  
Xin-Yan Geng ◽  
De-Xue Fu ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Cell Survival ◽  
Cancer Cells ◽  
Real Time Pcr ◽  
Therapeutic Target ◽  
Knockout Mouse ◽  
Prostate Cancer Cell ◽  
Prostate Cancer Cells ◽  
Anti Cancer

Abstract Background: Prostate cancer is the most commonly diagnosed malignancy and second leading cause of cancer death in American men. The histone demethylase KDM4A is reported to be overexpressed and plays a vital in multiple cancers through controlling gene expression by epigenetic regulation of H3K9 or H3K36 methylation marks. The biological role and mechanism of KDM4A in regulating AR activity in prostate cancer, however, remain to be established. Methods: KDM4A expression in PTEN knockout mouse was determined using western blotting, Real-time PCR and immunohistochemical. Functional assays, such as cell survival, cell colony formation, anchorage-independent growth and a xenograft tumor model were used to determine the oncogenic role of KDM4A in prostate cancer cells. Association of KDM4A with USP1 and the deubiquitination assay were determined by co-immunoprecipitation, immunofluorescent staining and immunoblotting. USP1-KDM4A axis promotes AR-dependent c-Myc expression was further investigated using western blotting, chromatin immunoprecipitation and Real-time PCR. The specific USP1 inhibitor ML323 was used for assessing the role of USP1 in prostate cancer cell survival. Co-expression of KDM4A with USP1 was determined by immunohistochemical staining in 146 prostate cancer tissue samples. Results: Herein, we reported KDM4A expression was upregulation in PTEN knockout mouse prostate tissue. Depletion of KDM4A in prostate cancer cells inhibited their proliferation and survival in vivo and vitro. Further studies reveal that USP1 is a deubiquitinase that regulates KDM4A K48-linked deubiquitin and stability. Interestingly, we found c-Myc was a key downstream effector of USP1-KDM4A/AR axis in driving prostate cancer cell proliferation. Notably, upregulation of KDM4A expression with high USP1 expression were observed in 70% of prostate tumors and inhibition of USP1 promotes prostate cancer cells response to therapeutic agent_enzalutamide. Our studies propose USP1 may be an anti-cancer therapeutic target in prostate cancer. Conclusions: Our findings demonstrate that USP1 deubiquitinates and stabilizes KDM4A, which promotes recruitment of AR to the c-Myc gene enhancer and highlight USP1 potential as an anti-cancer therapeutic target in prostate cancer. Keywords: USP1; Prostate cancer; KDM4A; Deubiquitination; Tumorigenesis

scholarly journals BRG1 is a prognostic indicator and a potential therapeutic target for prostate cancer

2018 ◽  
Author(s):  
Rohini Muthuswami ◽  
LeeAnn Bailey ◽  
Radhakrishnan Rakesh ◽  
Anthony Imbalzano ◽  
Jeffrey Nickerson ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Patient Outcome ◽  
Cancer Cells ◽  
Therapeutic Target ◽  
Prognostic Indicator ◽  
The Cancer Genome Atlas ◽  
Prostate Cancer Cells ◽  
Prostate Tumors ◽  
Grade Group ◽  
Normal Prostate

BRG1 is one of two mutually exclusive ATPases that function as the catalytic subunit of human SWI/SNF chromatin remodeling enzymes. BRG1 has been identified as a tumor suppressor in some cancer types but has been shown to be expressed at elevated levels, relative to normal tissue, in other cancers. Using the TCGA (The Cancer Genome Atlas) prostate cancer database, we determined that BRG1 mRNA and protein expression is elevated in prostate tumors relative to normal prostate tissue. Only 3 of 491 (0.6%) sequenced tumors showed amplification of the locus or mutation in the protein coding sequence, arguing against the idea that elevated expression due to amplification or expression of a mutant BRG1 protein is associated with prostate cancer. Kaplan-Meier survival curves showed that BRG1 expression in prostate tumors inversely correlated with survival. However, BRG1 expression did not correlate with Gleason score/ISUP Grade Group, indicating it is an independent predictor of tumor progression/patient outcome. To experimentally assess BRG1 as a possible therapeutic target, we treated prostate cancer cells with a biologic inhibitor called ADAADi that targets the activity of the SNF2 family of ATPases in biochemical assays but showed specificity for BRG1 in prior tissue culture experiments. The inhibitor decreased prostate cancer cell proliferation and induced apoptosis. When directly injected into xenografts established by injection of prostate cancer cells in mouse flanks, the inhibitor decreased tumor growth and increased survival. These results indicate the efficacy of pursuing BRG1 as both an indicator of patient outcome and as a therapeutic target.

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