Anti-tumor Activity of Curcumin against Androgen-independent Prostate Cancer Cells via Inhibition of NF-κB and AP-1 Pathway in vitro

The anti-tumor activity of curcumin against androgen-independent prostate cancer cells in vitro and the possible mechanism were investigated.After curcumin treatment,the effect of curcumin on the proliferation of prostate cancer PC-3 cells was assessed by CFSE staining.Flow cytometery（FCM） was performed to analyze the cell cycle and the induction of apoptosis of tumor cells.A luciferase reporter gene assay was used to determine the effects of curcumin on the activities of intracellular NF-κB and AP-1 signaling pathways.The results showed curcumin could effectively inhibit the proliferation of PC-3 cells in vitro（P0.05）.Cells were arrested at G2/M phase.After curcumin treatment,the percentage of apoptotic cells was significantly higher than in control group（P0.05）.The results of the luciferase assay revealed that curcumin selectively inhibited the activities of the NF-κB and AP-1 signaling pathways in PC-3 cells significantly.It was suggested that curcumin could exert anti-tumor activity against androgen-independent prostate cancer cells in vitro by inhibiting cellular proliferation and inducing apoptosis,which was probably contributed to the inhibition of transcription factors NF-κB and AP-1.

Identification of commonly regulated protein targets and molecular pathways in PC-3 and DU145 androgen-independent human prostate cancer cells treated with the curcumin analogue 1,5-bis(2-hydroxyphenyl)-1,4-pentadiene-3-one

Objective: To identify mutually regulated proteins in PC-3 and DU145 androgen-independent prostate cancer cell lines treated with 1,5-bis(2-hydroxyphenyl)-1,4-pentadiene-3-one(MS17), and to study the molecular pathways that contributed to the anticancer activity of MS17.Methods: PC-3 and DU145 cells were treated with 3 × EC_(50)(15 μM) concentration of MS17 for 24 h and were subjected to protein expression profiling using two-dimensional gel electrophoresis and protein identification by mass spectrometry.Selected differentially expressed proteins with significant P-value of P<0.05 and fold change over 1.5-folds were filtered through and ontologically classified.Mutually regulated proteins were ranked by fold change and identified as common protein targets of MS17.Results: Profiling data revealed that, the mutually down-regulated proteins included ACTB and ACTG associated with structural molecule activity, ACTN1 with cell cycle, ACTN4 with cell migration, HNRPK with apoptosis, PLST with morphogenesis and TERA with proteolysis.However, the expressions of CH60 and HS71 A respectively associated with response to unfolded protein demonstrated opposing regulation in PC-3 and DU145 cells.Pathway analysis of the differentially expressed proteins in PC-3 cells demonstrated the modulation of top pathways associated with cell-cell adhesion and cytoskeletal organization while in DU145 cells the pathways were associated with proteosomal degradation, regulation of electrolytes and water, regulation control of germ cells and organization of filament assembly/disassembly.Conclusions: The findings of the present study provide an understanding on the anti-tumorigenic activity of MS17 at the proteome level and warrant further research for its potential application for the management and treatment of androgen-independent prostate cancer.

Primary Research on Chinese Medicine Treatment of Androgen-Independent Prostate Cancer

Prostate cancer(PC) is a common malignant tumor in the male seniors,and its incidence has been ascending in China in recent years. Over 80%of the patients are diagnosed as being in the late stage and lose the opportunity of radical operation because of its early stage metastasis. Endocrinotherapy is regarded

The novel long noncoding RNA LOC283070 is involved in the transition of LNCaP cells into androgen-independent cells via its interaction with PHB2

We sought to investigate the underlying mechanism of action of the long noncoding RNA （IncRNA） LOC283070 in the development of androgen independence in prostate cancer. The interactions between LOC283070 and target proteins were investigated by RNA pull-down and RNA-binding protein immunoprecipitation （RIP） assays. Subceilular fractionation and quantitative reverse transcription-polymerase chain reaction （qRT-PCR） were used to detect the subcellular localization of LOC283070. Western blotting was performed to detect the expression of prohibitin 2 （PHB2）. Luciferase activity assays were performed to evaluate the effects of LOC283070 and PHB2 on the androgen receptor （AR） signaling pathway. A methyl thiazolyl tetrazolium （MTT） assay and a growth curve assay were used to test cell viability. Flow cytometry was performed to analyze cell cycles. A transwell assay was employed to test cell migration. We identified PHB2 as an interaction partner of LOC283070 in the pull-down and RIP experiments. Furthermore, we confirmed that the enrichment of L0C283070 with PHB2 in androgen-independent LNCaP （LNCaP-AI） cells was much greater than that in LNCaP cells. Moreover, the expression of PHB2 was not significantly different between the two cell lines, and the expression of LOC283070 in the nuclei of the LNCaP-AI cells was significantly greater than that in the LNCaP cells. In vitro data revealed that PHB2 overexpression significantly inhibited AR activity and cell proliferation and migration and induced accumulation of prostate cancer cells in GO/G1 phase. Moreover, the overexpression of LOC283070 fully abrogated the effects of PHB2 overexpression. In conclusion, we found that LOC283070 can bind to PHB2 located in the nucleus and inhibit its effect, and this is one of the mechanisms by which LOC283070 is involved in the transition of LNCaP cells into androgen-independent cells.

Polo-like kinase 1,on the rise from cell cycle regulation to prostate cancer development

Polo-like kinase 1(Plk1),a well-characterized member of serine/threonine kinases Plk family,has been shown to play pivotal roles in mitosis and cytokinesis in eu-karyotic cells.Recent studies suggest that Plk1 not only controls the process of mitosis and cytokinesis,but also,going beyond those previously described functions,plays critical roles in DNA replication and Pten null prostate cancer initiation.In this review,we briefly summarize the functions of Plk1 in mitosis and cytokinesis,and then mainly focus on newly discov-ered functions of Plk1 in DNA replication and in Pten-null prostate cancer initiation.Furthermore,we briefly introduce the architectures of human and mouse pros-tate glands and the possible roles of Plk1 in human prostate cancer development.And finally,the newly chemotherapeutic development of small-molecule Plk1 inhibitors to target Plk1 in cancer treatment and their translational studies are also briefly reviewed.

Regulatory effects of antitumor agent matrine on FOXO and PI3K-AKT pathway in castration-resistant prostate cancer cells

We previously demonstrated that matrine could inhibit the proliferating, migrating, as well as invading processes of both PC-3 and DU145 cells. However, the underlying molecular mechanisms have not yet been clearly defined. In this study, using various techniques such as high throughput sequencing technology, bioinformatics, quantitative real-time PCR, and immunoblot analysis,we aimed to understand whether matrine serves as a novel regulator of FOXO and PI3K-AKT signaling pathway. DU145 and PC-3 cell lines were cultured for 24 h in vitro. Cells were treated with either matrine or control serum for 48 h, followed by extraction of total RNA. The RNA was sequenced using HiSeq 2500 high-throughput sequencing platform (Illumina). A gene library was established and quality analysis of read data carried out. Integrated database from the website DAVID was used to analyze Gene Ontology (GO), and Kyoto encyclopedia of genes and genomes (KEGG) pathway of differential genes was used for pathway analysis, screening for fold differences of more than two times. The FOXO and PI3K-AKT signaling pathways were screened, and expression levels of mRNA and core protein detected by real-time PCR and immunoblotting, respectively. High throughput sequencing and GO analysis revealed that differentially expressed genes before and after treatment played an important role in cell metabolic process, growth process, anatomical structure formation, cellular component organization, and biological regulation. KEGG signal pathway analysis revealed that FOXO and PI3K-AKT signal pathways had a significant difference between before and after matrine-treated androgen-independent prostate cancer cells PC-3 and DU145. Real-time PCR showed that matrine treatment led to a significant increase in the expression levels of FOXO1A, FOXO3A, FOXO4, and FOXO6 in DU145 and PC-3 cells (P<0.01 or P<0.05), whereas the PI3K expression levels decreased (P<0.01). Similarly, immunoblotting revealed a significant increase (P<0.05) in the expression levels of FOXO1A FOXO3A, FOXO4, and FOXO6 in both PC-3 and DU145 cells, whereas PI3K expression levels decreased (P<0.05). Matrine had a broad regulating effect on the mRNA expression profiles of both PC-3 and DU145 cells. Matrine may inhibit cell proliferation, migration, as well as invasion, and induce apoptosis in both PC-3 and DU145 cells through FOXO and PI3K-AKT signaling pathways. Matrine could therefore be used as a complementary drug to present chemotherapeutic agents, for treating androgen-independent prostate cancer.

Emerging role of transforming growth factor-β-regulated long non-coding RNAs in prostate cancer pathogenesis

Prostate cancer(PCa)is the most common malignancy in men.Despite aggressive therapy involving surgery and hormonal treatments,the recurrence and emergence of metastatic castration-resistant prostate cancer(CRPCa)remain a major challenge.Dysregulation of the transforming growth factor-β(TGF-β)signaling pathway is crucial to PCa development and progression.This also contributes to androgen receptor activation and the emergence of CRPC.In addition,TGF-β signaling regulates long non-coding RNA(lncRNA)expression in multiple cancers,including PCa.Here,we discuss the complex regulatory network of lncRNAs and TGF-β signaling in PCa and their potential applications in diagnosing,prognosis,and treating PCa.Further investigations on the role of lncRNAs in the TGF-β pathway will help to better understand PCa pathogenesis.

NES1/KLK10 and hNIS gene therapy enhanced iodine-131 internal radiation in PC3 proliferation inhibition

NES1 gene is thought to be a tumor-suppressor gene.Our previous study found that overexpression of NES1 gene in PC3 cell line could slow down the tumor proliferation rate,associated with a mild decrease in BCL-2 expression.The BCL-2 decrease could increase the sensitivity of radiotherapy to tumors.Thus,we supposed to have an“enhanced firepower”effect by combining overexpressed NES1 gene therapy and 131I radiation therapy uptake by overexpressed hNIS protein.We found a weak endogenous expression of hNIS protein in PC3 cells and demonstrated that the low expression of hNIS protein in PC3 cells might be the reason for the low iodine uptake.By overexpressing hNIS in PC3,the radioactive iodine uptake ability was significantly increased.Results of in vitro and in vivo tumor proliferation experiments and 18F-fluorothymidine(18F-FLT)micro-positron emission tomography/computed tomography(micro-PET/CT)imaging showed that the combined NES1 gene therapy and 131I radiation therapy mediated by overexpressed hNIS protein had the best tumor proliferative inhibition effect.Immunohistochemistry showed an obvious decrease of Ki-67 expression and the lowest BCL-2 expression.These data suggest that via inhibition of BCL-2 expression,overexpressed NES1 might enhance the effect of radiation therapy of 131I uptake in hNIS overexpressed PC3 cells.