DU145 Prostate Cancer Cells Research Articles

MBTPS2 acts as a regulator of lipogenesis and cholesterol synthesis through SREBP signalling in prostate cancer

BackgroundProstate cancer is the most common cancer in men in the developed world, with most deaths caused by advanced and metastatic disease which has no curative options. Here, we identified Mbtps2 alteration to be associated with metastatic disease in an unbiased in vivo screen and demonstrated its regulation of fatty acid and cholesterol metabolism.MethodsThe Sleeping Beauty transposon system was used to randomly alter gene expression in the PtenNull murine prostate. MBTPS2 was knocked down by siRNA in LNCaP, DU145 and PC3 cell lines, which were then phenotypically investigated. RNA-Seq was performed on LNCaP cells lacking MBTPS2, and pathways validated by qPCR. Cholesterol metabolism was investigated by Filipin III staining.ResultsMbtps2 was identified in our transposon-mediated in vivo screen to be associated with metastatic prostate cancer. Silencing of MBTPS2 expression in LNCaP, DU145 and PC3 human prostate cancer cells reduced proliferation and colony forming growth in vitro. Knockdown of MBTPS2 expression in LNCaP cells impaired cholesterol synthesis and uptake along with reduced expression of key regulators of fatty acid synthesis, namely FASN and ACACA.ConclusionMBTPS2 is implicated in progressive prostate cancer and may mechanistically involve its effects on fatty acid and cholesterol metabolism.

A Multi-Level Systems Biology Analysis of Aldrin’s Metabolic Effects on Prostate Cancer Cells

Although numerous studies support a dose-effect relationship between Endocrine disruptors (EDs) and the progression and malignancy of tumors, the impact of a chronic exposure to non-lethal concentrations of EDs in cancer remains unknown. More specifically, a number of studies have reported the impact of Aldrin on a variety of cancer types, including prostate cancer. In previous studies, we demonstrated the induction of the malignant phenotype in DU145 prostate cancer (PCa) cells after a chronic exposure to Aldrin (an ED). Proteins are pivotal in the regulation and control of a variety of cellular processes. However, the mechanisms responsible for the impact of ED on PCa and the role of proteins in this process are not yet well understood. Here, two complementary computational approaches have been employed to investigate the molecular processes underlying the acquisition of malignancy in prostate cancer. First, the metabolic reprogramming associated with the chronic exposure to Aldrin in DU145 cells was studied by integrating transcriptomics and metabolomics via constraint-based metabolic modeling. Second, gene set enrichment analysis was applied to determine (i) altered regulatory pathways and (ii) the correlation between changes in the transcriptomic profile of Aldrin-exposed cells and tumor progression in various types of cancer. Experimental validation confirmed predictions revealing a disruption in metabolic and regulatory pathways. This alteration results in the modification of protein levels crucial in regulating triacylglyceride/cholesterol, linked to the malignant phenotype observed in Aldrin-exposed cells.

Adipocytes reprogram prostate cancer stem cell machinery.

It is now well-established that an obese condition correlates with a higher risk of prostate cancer (PCa). A crosstalk between adipose tissue and PCa has been observed but is still poorly characterized. Herein, we demonstrated that 3T3-L1 adipocyte conditioned media (CM) could endow PC3 and DU145 PCa cells with stemness properties, by stimulating their sphere formation ability and promoting CD133 and CD44 expression. Moreover, after exposure to adipocyte CM both PCa cell lines underwent partial epithelial-to-mesenchymal transition (EMT), with E-/N-cadherin switch and Snail upregulation. Specifically, these changes in PC3 and DU145 cell phenotype were accompanied by increased tumor clonogenic activity and survival, as well as by enhanced invasion, anoikis resistance and matrix metalloproteinase (MMP) production. Finally, adipocyte CM-treated PCa cells exhibited reduced responsiveness to both docetaxel and cabazitaxel, demonstrating greater chemoresistance. Overall, these data indicate that adipose tissue can effectively contribute to PCa aggressiveness by reprogramming the cancer stem cell (CSC) machinery. Adipocytes endow prostate cancer cells with stem-like properties and mesenchymal traits, increasing their tumorigenicity, invasion and chemoresistance.

New Bioactive β-Resorcylic Acid Derivatives from the Alga-Derived Fungus Penicillium antarcticum KMM 4685.

Five new β-resorcylic acid derivatives, 14-hydroxyasperentin B (1), β-resoantarctines A-C (3, 5, 6) and 8-dehydro-β-resoantarctine A (4), together with known 14-hydroxyasperentin (5'-hydroxyasperentin) (2), were isolated from the ethyl acetate extract of the fungus Penicillium antarcticum KMM 4685 associated with the brown alga Sargassum miyabei. The structures of the compounds were elucidated by spectroscopic analyses and modified Mosher's method, and the biogenetic pathways for compounds 3-6 were proposed. For the very first time, the relative configuration of the C-14 center of a known compound 2 was assigned via analyses of magnitudes of the vicinal coupling constants. The new metabolites 3-6 were biogenically related to resorcylic acid lactones (RALs); however, they did not possess lactonized macrolide elements in their structures. Compounds 3, 4 and 5 exhibited moderate cytotoxic activity in LNCaP, DU145 and 22Rv1 human prostate cancer cells. Moreover, these metabolites could inhibit the activity of p-glycoprotein at their noncytotoxic concentrations and consequently synergize with docetaxel in p-glycoprotein-overexpressing drug-resistant cancer cells.

Metabolic Disruption of Gold Nanospheres, Nanostars and Nanorods in Human Metastatic Prostate Cancer Cells.

Nanomaterials offer a broad spectrum of applications in biomedicine. The shapes of gold nanoparticles could modulate tumor cell behavior. Spherical (AuNPsp), stars (AuNPst) and rods (AuNPr) shapes of polyethylene glycol coated-gold nanoparticles (AuNPs-PEG) were synthesized. Metabolic activity, cellular proliferation, and reactive oxygen species (ROS) were measured and the impact of AuNPs-PEG in metabolic enzymes function was evaluated by RT-qPCR in PC3, DU145, and LNCaP prostate cancer cells. All AuNPs were internalized, and the different morphologies of AuNPs showed to be an essential modulator of metabolic activity. For PC3 and DU145, the metabolic activity of AuNPs was found to rank in the following order from lowest to highest: AuNPsp-PEG, AuNPst-PEG, and AuNPr-PEG. Regarding LNCaP cells, the AuNPst-PEG were less toxic, followed by AuNPsp-PEG and AuNPr-PEG, but it seems not to be dose-dependent. The proliferation was lower in AuNPr-PEG in PC3 and DU145 cells but was stimulated around 10% in most conditions (0.001-0.1 mM) in LNCaP cells (not statistically significant). For 1 mM, LNCaP cells showed a significant decrease in proliferation only for AuNPr-PEG. The outcomes of the current study demonstrated that different AuNPs conformations influence cell behavior, and the correct size and shape must be chosen considering its final application in the field of nanomedicine.

Development of Highly Efficient Estrogen Receptor β-Targeted Near-Infrared Fluorescence Probes Triggered by Endogenous Hydrogen Peroxide for Diagnostic Imaging of Prostate Cancer

Hydrogen peroxide is one of the most important reactive oxygen species, which plays a vital role in many physiological and pathological processes. A dramatic increase in H2O2 levels is a prominent feature of cancer. Therefore, rapid and sensitive detection of H2O2 in vivo is quite conducive to an early cancer diagnosis. On the other hand, the therapeutic potential of estrogen receptor beta (ERβ) has been implicated in many diseases including prostate cancer, and this target has attracted intensive attention recently. In this work, we report the development of the first H2O2-triggered ERβ-targeted near-infrared fluorescence (NIR) probe and its application in imaging of prostate cancer both in vitro and in vivo. The probe showed good ERβ selective binding affinity, excellent H2O2 responsiveness and near infrared imaging potential. Moreover, in vivo and ex vivo imaging studies indicated that the probe could selectively bind to DU-145 prostate cancer cells and rapidly visualizes H2O2 in DU-145 xenograft tumors. Mechanistic studies such as high-resolution mass spectrometry (HRMS) and density functional theory (DFT) calculations indicated that the borate ester group is vital for the H2O2 response turn-on fluorescence of the probe. Therefore, this probe might be a promising imaging tool for monitoring the H2O2 levels and early diagnosis studies in prostate cancer research.

Atezolizumab Retains Cellular Binding to Programmed Death Ligand 1 Following Aerosolization via Mesh Nebulizer.

Cytotoxic inhalable drugs were shown to be advantageous in treating malignancies of the respiratory tract. However, these drugs have not always presented a safe profile and were reported to induce local adverse events. Protein-based anticancer drugs, such as immune checkpoint and vascular endothelial growth factor inhibitors, do not induce tissue injury, nor do they exhibit vesicant properties upon direct contact with tissues. Protein drugs are susceptible to the heat and stress encountered during droplet generation for delivery by nebulization. The aim of this study was to investigate the capacity of atezolizumab, an antibody to programmed death ligand 1, to bind target cells after nebulization with a vibrating mesh (VM) nebulizer. We compared Fourier-transformed infrared (FTIR) and Raman spectra of native atezolizumab (60 mg/ml) and its nebulized form following 10-min nebulization in a piezoceramic VM nebulizer. The binding of atezolizumab to DU-145 prostate cancer cells was evaluated using competitive blocking of anti-CD274 staining. Nebulization did not induce Raman or FTIR spectral modification nor did it affect the binding capacity of atezolizumab. Conversely, heat-inactivated atezolizumab lost its cell-binding capacity and did not reduce anti-CD274 immunostaining. Native and nebulized atezolizumab displayed identical spectra, whereas the FTIR spectra of the heat-inactivated drug was significantly altered. VM nebulization does not obliterate the functionality of the drug atezolizumab. The integrity of a nebulized form can be rapidly assessed by FTIR and Raman spectrometry.

Discovery of SI 1/20 and SI 1/22 as Mutual Prodrugs of 5-Fluorouracil and Imidazole-Based Heme Oxygenase 1 Inhibitor with Improved Cytotoxicity in DU145 Prostate Cancer Cells.

In this work, we extend the concept of 5-fluorouracil/heme oxygenase 1 (5-FU/HO-1) inhibitor hybrid as an effective strategy for enhancing 5-FU-based anticancer therapies. For this purpose, we designed and synthesized new mutual prodrugs, named SI 1/20 and SI 1/22, in which the two active parent drugs (i. e., 5-FU and an imidazole-based HO-1 inhibitor) were connected through an easily cleavable succinic linker. Experimental hydrolysis rate, and in silico ADMET predictions were indicative of good drug-likeness and pharmacokinetic properties. Novel hybrids significantly reduced the viability of prostate DU145 cancer cells compared to the parent compounds 5-FU and HO-1 inhibitor administered alone or in combination. Interestingly, both compounds showed statistically significant lower toxicity, than 5-FU at the same dose, against non-tumorigenic human benign prostatic hyperplasia (BPH-1) cell line. Moreover, the newly synthesized mutual prodrugs inhibited the HO-1 activity both in a cell-free model and in vitro, as well as downregulated the HO-1 expression and increased the reactive oxygen species (ROS) levels.

Euchromatic histone lysine methyltransferase 2 facilitates radioresistance in prostate cancer by repressing endoplasmic reticulum protein 29 transcription.

Prostate cancer is one of the most common cancers in men. This study was conducted to investigate the role of euchromatic histone lysine methyltransferase 2 (EHMT2) and endoplasmic reticulum protein 29 (ERP29) in the progression of radioresistance in prostate cancer. The expression of EHMT2 and ERP29 in prostate cancer cells and during the progression of radioresistance was detected using quantitative reverse transcription-polymerase chain reaction and western blotting, and the interaction between EHMT2 and ERP29 was investigated. The proliferation of transfected cells under x-ray irradiation was determined using the methyl thiazolyl tetrazolium and colony formation assays. Flow cytometry was used to analyze the apoptosis of the transfected cells under x-ray irradiation. Nude mice were subcutaneously injected with prostate cancer (DU145) cells stably transfected with sh-ERP29 or sh-NC. The effect of ERP29 expression on radioresistance in nude mice was assessed by x-ray irradiation. The expression of EHMT2 was upregulated and that of ERP29 was downregulated in prostate cancer cells during radioresistance progression. EHMT2 downregulation suppressed radioresistance in DU145 and androgen-sensitive prostate cancer (LNCaP) cells. In irradiated DU145 cells, EHMT2 inhibition decreased the number of colonies and accelerated apoptosis. The transcription of ERP29 was suppressed by EHMT2 by upregulating H3K9me2 and downregulating H3K4me3, thereby regulating radioresistance in prostate cancer cells. In addition, the downregulation of ERP29 promoted the progression of radioresistance in prostate cancer cells in nude mice. EHMT2 promotes radioresistance in prostate cancer cells by repressing ERP29 transcription.

Antitumoral activity of Caralluma europaea on colorectal and prostate cancer cell lines

ABSTRACT Caralluma europaea is a medicinal plant used in Moroccan popular medicine, which has been employed as a remedy attributed to its anti-inflammatory, antipyretic, antinociceptive, antidiabetic, neuroprotective, and antiparasitic properties. The aim of the present study was to investigate the antitumor activity of both the methanolic and aqueous extract of C. europaea. The effects of increasing concentrations of aqueous and methanolic extracts on human colorectal cancer HT-29 and HCT116 cell lines and human prostate cancer PC3 and DU145 cell lines were examined on cell proliferation using MTT assay and cell cycle analysis. The induction of apoptosis was also assessed by determining protein expression of caspase-3 and poly-ADP-ribose polymerase (PARP) cleavage by western blot. The methanolic extract of C. europaea exerted significant antiproliferative effects on HT-29 (IC50 values 73 µg/ml), HCT116 (IC50 values 67 µg/ml), PC3 (IC50 values 63 µg/ml) and DU145 cells (IC50 values 65 µg/ml) after 48 hr treatment. Further, incubation with methanolic extract of C. europaea induced cell cycle arrest in G1 phase and an apoptotic process for all treated cell lines. In conclusion, the present results suggest that C. europaea, exhibited that these natural compounds are significant apoptosis inducers which may have considerable potential for development of effective natural product anticancer agents.

Combination Modality Using Quercetin to Enhance the Efficacy of Docetaxel in Prostate Cancer Cells.

The standard of care chemotherapy drug presently used to treat castration-resistant prostate cancer (CRPC), docetaxel (Doc), also develops chemoresistance, thereby reducing its clinical utility. Since resistance to chemotherapy drugs can be overcome by co-treatment with plant-based bio-active compounds we undertook the present study to evaluate if quercetin (Que), a flavonoid present in plants such as onions, apples, olives, and grapes can enhance the efficacy of Doc. We studied the separate and combined effects of Que and Doc at different doses and different combination approaches in two different prostate cancer cell lines, DU-145 (moderately aggressive) and PC-3 (very aggressive), and assessed the effects of these combinations on viability, proliferation, and apoptosis. Monotherapy with these drugs showed dose-dependent cytotoxicity; however, only Doc monotherapy showed a statistically significant difference in IC50 levels (IC50 = 4.05 ± 0.52 nM for PC-3 and IC50 = 2.26 ± 0.22 nM for DU-145). In combination treatment, we used three different treatment approaches (TAP). The concentrations and range analyzed were chosen based on the approximate cytotoxicity of 30-50% when the drugs were used individually. Our observations indicate that the most beneficial effect of the Que and Doc combination was obtained with the TAP-2 approach, which is pre-treatment with all doses of Que for 24 h followed by low doses of Doc for another 24 h. Using this approach, we observed synergism at low concentrations of Doc (0.5 and 1.0 nM) and all concentrations of Que. An additive effect was observed at moderate and high concentrations of Doc (1.5, 2.0, and 2.5 nM) and all concentrations of Que in both cell lines. The TAP-2 strategy was also helpful in overcoming Doc resistance in resistant CaP cells. In summary, Que improved the therapeutic effect of Doc in CRPC, and it is proposed that this improvement is mediated through multiple mechanisms. This study provides a novel therapeutic modality for an effective combination using Doc and Que to enhance the efficacy of Doc in an innocuous manner for Doc resistance and CRPC treatment.

Expression of the Low-density Lipoprotein Receptor (LDLR) Gene Family in CD133+/CD44+ Prostate Cancer Stem Cells

Aim: The low-density lipoprotein receptor gene (LDLR) family plays a fundamental role in many malignancies and may have a putative cancer-boosting function. In our study, we have attempted to comparatively investigate the differential gene expressions of LDLR family in normal prostate epithelial cell line (RWPE-1), prostate cancer cell line (DU145 cell line), prostate cancer stem cells (DU145 CSCs) and non-CSCs (DU145 non-CSCs, bulk population). 
 Materials and Methods: Cancer stem cells in DU-145 prostate cancer cell line were isolated by flow cytometry according to CD133 and CD44 cell surface properties. Whole transcriptome sequencing data was comprehensively analyzed for each group. The protein-protein interaction network was determined using the STRING protein database.
 Results: Our data showed that the expression levels of LRP1, LRP3, LRP8 and LRP11 were increased in the DU145 CSCs relative to the normal prostate epithelial cell line. 
 Conclusion: Overall, our data suggest that the LRP functions and/or the expression in prostate cancer may ultimately change the invasive phenotype of the CSCs.

Optimized Method for Using Embryonic Microenvironment to Reprogram Cancer Stem Cells

Purpose: The embryonic microenvironment contains many properties that have not yet been fully explored. Our aim in this study is to report an optimized and efficient method that enables investigating the effects of the secretome of pluripotent embryonic stem cells on cancer stem cells.
 Methods: The study is performed with a chimeric model consisted of mouse blastocysts, human prostate cancer stem cells and non-cancer stem cells. Ovulation induced mice were used for blastocyst collection. DU145 prostate cancer cell line was separated into cancer stem cells and non-cancer stem cells according to cancer stem cells biomarker expressions by fluorescent activated cell sorting method. Human prostate cancer stem cells and non-cancer stem cells were microinjected into 4-day blastocyst culture in vitro by intracytoplasmic sperm injection method.
 Results: Chimeric models provide us great convenience in basic oncological studies. In this study, using a chimeric model, we were able to study the secretome of mouse embryonic stem cells and their effect on cancer stem cells. The method is efficient and yield promising result; and could be used to study the effects on other cells as well.
 Conclusion: The embryonic stem cell microenvironment is suggested to have a great regenerative capacity which is, nowadays, the center of attraction for cancer research studies. Ethical issues restrict the human embryo studies, however, mimicking the in vivo human microenvironment with 3D cell cultures or bioprinting are now possible. Finally, optimization of new methods including 3D cell cultures with human cell lines will be a great opportunity for better understanding the reprogramming notion.

Experimental validation of proton boron capture therapy for glioma cells

Proton boron capture therapy (PBCT) has emerged from particle acceleration research for enhancing the biological effectiveness of proton therapy. The mechanism responsible for the dose increase was supposed to be related to proton-boron fusion reactions (11B + p → 3α + 8.7 MeV). There has been some experimental evidence that the biological efficiency of protons is significantly higher for boron-11-containing prostate or breast cancer cells. The aim of this study was to evaluate the sensitizing potential of sodium borocaptate (BSH) under proton irradiation at the Bragg peak of cultured glioma cells. To address this problem, cells of two glioma lines were preincubated with 80 or 160 ppm boron-11, irradiated both at the middle of 200 MeV beam Spread-Out Bragg Peak (SOBP) and at the distal end of the 89.7 MeV beam SOBP and assessed for the viability, as well as their ability to form colonies. Our results clearly show that BSH provides for only a slight, if any, enhancement of the effect of proton radiation on the glioma cells in vitro. In addition, we repeated the experiments using the Du145 prostate cancer cell line, for which an increase in the biological efficiency of proton irradiation in the presence of sodium borocaptate was demonstrated previously. The data presented add new argument against the efficiency of proton boron capture therapy when based solely on direct dose-enhancement effect by the proton capture nuclear reaction, underlining the need to investigate the indirect effects of the secondary alpha irradiation depending on the state and treatment conditions of the irradiated tissue.

Analyzing the interactome of human CK2β in prostate carcinoma cells reveals HSP70-1 and Rho guanin nucleotide exchange factor 12 as novel interaction partners.

CK2β is the non-catalytic modulating part of the S/T-protein kinase CK2. However, the overall function of CK2β is poorly understood. Here, we report on the identification of 38 new interaction partners of the human CK2β from lysates of DU145 prostate cancer cells using photo-crosslinking and mass spectrometry, whereby HSP70-1 was identified with high abundance. The KD value of its interaction with CK2β was determined as 0.57 μM by microscale thermophoresis, this being the first time, to our knowledge, that a KD value of CK2β with another protein than CK2α or CK2α' was quantified. Phosphorylation studies excluded HSP70-1 as a substrate or activity modulator of CK2, suggesting a CK2 activity independent interaction of HSP70-1 with CK2β. Co-immunoprecipitation experiments in three different cancer cell lines confirmed the interaction of HSP70-1 with CK2β in vivo. A second identified CK2β interaction partner was Rho guanin nucleotide exchange factor 12, indicating an involvement of CK2β in the Rho-GTPase signal pathway, described here for the first time to our knowledge. This points to a role of CK2β in the interaction network affecting the organization of the cytoskeleton.

Comparative Analysis of Dasatinib Effect between 2D and 3D Tumor Cell Cultures

Three-dimensional cell culture methods are able to confer new predictive relevance to in vitro tumor models. In particular, the 3D multicellular tumor spheroids model is considered to better resemble tumor complexity associated with drug resistance compared to the 2D monolayer model. Recent advances in 3D printing techniques and suitable biomaterials have offered new promises in developing 3D tissue cultures at increased reproducibility and with high-throughput characteristics. In our study, we compared the sensitivity to dasatinib treatment in two different cancer cell lines, prostate cancer cells DU145 and glioblastoma cells U87, cultured in the 3D spheroids model and in the 3D bioprinting model. DU145 and U87 cells were able to proliferate in 3D alginate/gelatin bioprinted structures for two weeks, forming spheroid aggregates. The treatment with dasatinib demonstrated that bioprinted cells were considerably more resistant to drug toxicity than corresponding cells cultured in monolayer, in a way that was comparable to behavior observed in the 3D spheroids model. Recovery and analysis of cells from 3D bioprinted structures led us to hypothesize that dasatinib resistance was dependent on a scarce penetrance of the drug, a phenomenon commonly reported also in spheroids. In conclusion, the 3D bioprinted model utilizing alginate/gelatin hydrogel was demonstrated to be a suitable model in drug screening when spheroid growth is required, offering advantages in feasibility, reproducibility, and scalability compared to the classical 3D spheroids model.

Shear loaded osteocyte-like-cells affect epithelial and mesenchymal gene expression in DU145 prostate cancer cells, while decreasing their invasion in vitro

Once prostate cancer (PC) metastasizes towards bone the 5-year survival rates drop with 70%, but it is largely unknown why. Bone is continuously mechanically loaded, which likely modulates the paracrine signaling from osteocytes towards PC cells to affect tumor behavior. We hypothesize that shear loaded osteocytes affect PC cell proliferation, invasion and epithelial and mesenchymal-related gene and protein expression. We cultured human DU145 cells, a commonly used cell line for prostate cancer metastases, in the conditioned medium (CM) from shear loaded or unloaded human osteocyte-like-cells (OCYLCs) for 1 and 3 days and assessed their number by staining nuclei with DAPI, their invasion by performing an invasion assay, and epithelial-to-mesenchymal (EMT)-related gene and protein expression by qPCR and immunocytochemistry. CM of shear loaded OCYLCs did not affect DU145 cell number compared to CM of static cultured OCYLCs, but decreased their invasion 1.34-fold. CM of shear loaded OCYLCs enhanced expression of epithelial genes: SYND1 and CDH1 after day 1, while it also enhanced CDH1 after day 3. CM of shear loaded osteocytes enhanced mesenchymal genes: VMN, Snail and MIP2 after day 1, while it decreased expression of mesenchymal CYR61 after day 3. We conclude that CM of shear loaded OCYLCs does not affect DU145 cell proliferation, but decreases their invasion, and differentially affects their EMT-related gene expression. Identifying paracrine signals from shear loaded osteocytes that decrease PC cell invasion may provide novel leads in developing treatments for bone metastases from PC.

NEK6 Regulates Redox Balance and DNA Damage Response in DU-145 Prostate Cancer Cells.

NEK6 is a central kinase in developing castration-resistant prostate cancer (CRPC). However, the pathways regulated by NEK6 in CRPC are still unclear. Cancer cells have high reactive oxygen species (ROS) levels and easily adapt to this circumstance and avoid cell death by increasing antioxidant defenses. We knocked out the NEK6 gene and evaluated the redox state and DNA damage response in DU-145 cells. The knockout of NEK6 decreases the clonogenic capacity, proliferation, cell viability, and mitochondrial activity. Targeting the NEK6 gene increases the level of intracellular ROS; decreases the expression of antioxidant defenses (SOD1, SOD2, and PRDX3); increases JNK phosphorylation, a stress-responsive kinase; and increases DNA damage markers (p-ATM and γH2AX). The exogenous overexpression of NEK6 also increases the expression of these same antioxidant defenses and decreases γH2AX. The depletion of NEK6 also induces cell death by apoptosis and reduces the antiapoptotic Bcl-2 protein. NEK6-lacking cells have more sensitivity to cisplatin. Additionally, NEK6 regulates the nuclear localization of NF-κB2, suggesting NEK6 may regulate NF-κB2 activity. Therefore, NEK6 alters the redox balance, regulates the expression of antioxidant proteins and DNA damage, and its absence induces the death of DU-145 cells. NEK6 inhibition may be a new strategy for CRPC therapy.

Atractylenolide I inhibits EMT and enhances the antitumor effect of cabozantinib in prostate cancer via targeting Hsp27.

To investigate the effect of Hsp27 and the inhibitory effect of Atractylenolide I (ATL-1) on the proliferation of prostate cancer cell DU145 and PC-3. MTT assay was used to detect the inhibitory effect of silencing Hsp27 and ATL-1 on DU145 and PC-3 proliferation of prostate cancer cells. TUNEL detected the apoptosis rate of prostate cancer cell DU145 and PC-3 after silencing Hsp27 and ATL-1 treated. qRT-PCR was used to detect the changes of apoptosis related genes caspase-3, PARP, Bax and Bcl-2 in prostate cancer cell DU145 and PC-3 after the effect of silencing Hsp27 and ATL-1 treated. At the same time, the antitumor effect of ATL-1 combined with cabozantinib was analyzed. Hsp27 was highly expressed in human prostate cancer. MTT assay showed that ATL-1 inhibited the proliferation of prostate cancer cells DU145 and PC-3 compared with the control group. TUNEL results showed that silencing Hsp27 and ATL-1 treated could significantly promote the apoptosis of prostate cancer cells DU145 and PC-3 compared with the control group. qRT-PCR results showed that compared with the control group, ATL-1 could promote the expression of caspase-3, PARP and Bax in DU145 and PC-3 prostate cancer cells. Inhibition of Hsp27 by ATL-1 reduced cell viability and induced apoptosis. ATL-1 inhibits the antitumor effect of Hsp27 - enhanced cabozantinib. Hsp27 regulates eIF4E and mediates cell protection. Silencing Hsp27 inhibits EMT. ATL-1 can inhibit the malignant evolution of prostate cancer cells by inhibiting Hsp27/eIF4E. ATL-1 also enhanced chemosensitization of cabozantinib in prostate cancer.

Protein Kinase D3 (PKD3) Requires Hsp90 for Stability and Promotion of Prostate Cancer Cell Migration.

Prostate cancer metastasis is a significant cause of mortality in men. PKD3 facilitates tumor growth and metastasis, however, its regulation is largely unclear. The Hsp90 chaperone stabilizes an array of signaling client proteins, thus is an enabler of the malignant phenotype. Here, using different prostate cancer cell lines, we report that Hsp90 ensures PKD3 conformational stability and function to promote cancer cell migration. We found that pharmacological inhibition of either PKDs or Hsp90 dose-dependently abrogated the migration of DU145 and PC3 metastatic prostate cancer cells. Hsp90 inhibition by ganetespib caused a dose-dependent depletion of PKD2, PKD3, and Akt, which are all involved in metastasis formation. Proximity ligation assay and immunoprecipitation experiments demonstrated a physical interaction between Hsp90 and PKD3. Inhibition of the chaperone-client interaction induced misfolding and proteasomal degradation of PKD3. PKD3 siRNA combined with ganetespib treatment demonstrated a specific involvement of PKD3 in DU145 and PC3 cell migration, which was entirely dependent on Hsp90. Finally, ectopic expression of PKD3 enhanced migration of non-metastatic LNCaP cells in an Hsp90-dependent manner. Altogether, our findings identify PKD3 as an Hsp90 client and uncover a potential mechanism of Hsp90 in prostate cancer metastasis. The molecular interaction revealed here may regulate other biological and pathological functions.