The Effect of Fatty Acids on Ciprofloxacin Cytotoxic Activity in Prostate Cancer Cell Lines. Does Lipid Component Enhance Anticancer Ciprofloxacin Potential?

Purpose: To assess cytotoxic effect of ciprofloxacin conjugates with fatty acids on prostate cancer cells (LNCaP and DU-145) with different hormone sensitivity, based on previous promising results from the PC3 cells. Methods: Cytotoxicity were estimated using MTT and LDH tests, whereas its mechanisms were estimated by apoptosis and IL-6 assays. The intensity of proteins involved in lipid metabolism was determined using ML-CS assay. Results: The hormone insensitive DU-145 cells were more vulnerable than the hormone sensitive LNCaP cells. The IC50 values for oleic (4), elaidic (5) and docosahexaenoic acid (8) conjugates were 20.2 µM, 17.8 µM and 16.5 µM, respectively, in DU-145 cells, whereas in LNCaP cells IC50 exceeded 20 µM. The strong conjugate cytotoxicity was confirmed in the LDH test, the highest (70.8%) for compound (5) and 64.2% for compound (8) in DU-145 cells. This effect was weaker for LNCaP cells (around 60%). The cytotoxic effect of unconjugated ciprofloxacin and fatty acids was weaker. The early apoptosis was predominant in LNCaP while in DU-145 cells both early and late apoptosis was induced. The tested conjugates decreased IL-6 release in both cancer cell lines by almost 50%. Proteomic analysis indicated influence of the ciprofloxacin conjugates on lipid metabolic proteins in prostatic cancer. Conclusion: Our findings suggested the cytotoxic potential of ciprofloxacin conjugates with reduction in proteins involved in prostate cancer progress.

In Situ Detection of Hydrogen Sulfide in 3D-Cultured, Live Prostate Cancer Cells Using a Paper-Integrated Analytical Device

In this study, a paper-integrated analytical device that combined a paper-based colorimetric assay with a paper-based cell culture platform was developed for the in situ detection of hydrogen sulfide (H2S) in three-dimensional (3D)-cultured, live prostate cancer cells. Two kinds of paper substrates were fabricated using a simple wax-printing methodology to form the cell culture and detection zones, respectively. LNCaP cells were seeded directly on the paper substrate and grown in the paper-integrated analytical device. The cell viability and H2S production of LNCaP cells were assessed using a simple water-soluble tetrazolium salt colorimetric assay and H2S-sensing paper, respectively. The H2S-sensing paper showed good sensitivity (sensitivity: 6.12 blue channel intensity/μM H2S, R2 = 0.994) and a limit of quantification of 1.08 μM. As a result, we successfully measured changes in endogenous H2S production in 3D-cultured, live LNCaP cells within the paper-integrated analytical device while varying the duration of incubation and substrate concentration (L-cysteine). This paper-integrated analytical device can provide a simple and effective method to investigate H2S signaling pathways and drug screening in a 3D culture model.

Antitumor Activities of Green Tea by Up-regulation of miR-181a Expression in LNCaP Cells Using 3D Cell Culture Model

Background: Prostate Cancer (PCa) is the major reason for the high mortality rates among men worldwide. In fact, current therapeutic approaches are not successful. It appears that discovering more effective methods considering several parameters such as availability, low cost, and no toxicity to normal cells is one of the biggest challenges for interested researchers. Green tea (extracted from the plant Camellia sinensis) with high level of polyphenolic compounds and as the most globally consumed beverage has attracted considerable interest. MicroRNAs (or miRNAs) were considered as novel tools in cancer therapy which modulate various biological events in cell by regulation of gene expression. The aim of the current study was to evaluate the antitumor activity of green tea in LNCaP cells through up-regulation of miR-181a expression. Methods: First, LNCaP cells were cultured and by using quantitative real time PCR (qRT-PCR) and western blot methods, the expression levels of Bax and BCL2 were analyzed. Next, a 3D cell culture model was applied to evaluate the expression of miRNA-181a in LNCaP cells. Results: It was shown that green tea induced cellular apoptosis. The high number of apoptotic nuclei was also shown by using DAPI staining. The inhibition of tumor growth was revealed by analyzing the size and number of spheroids. Also, up-regulation of miR-181a expression in LNCaP cells was revealed after treatment with green tea. Conclusion: Our results are helpful to design antitumor regimens based on consumption of green tea through up-regulation of miRNA-181a expression and induction of apoptosis.

LncRNA DANCR Restrains Sensitivity to 5-fluorouracil in Prostate Cancer through Sponging MiR-577

ABSTRACT This present study explored the functions of lncRNA DANCR on regulating sensitivity to 5-fluorouracil (5- FU) in prostate cancer in vitro. The RT-qPCR examined RNA expressions of LNCRNA DANCR in RWPE-1, VCaP, PC3 and LNCaP cells, which also measured RNA levels of miR-577 in PC3 cells. DANCR was highly expressed in prostate cancer cell lines. 5-FU (0, 1, 5 and 10¼M) treatment induced the decrease of PC3 cell viability and low RNA expressions of DANCR but increased miR-577 in PC3 cells. The luciferase reporter test detected the binding between DNACR and miR- 577 . Interactions between DANCR and miR-577 were examined. Knockdown of DANCR downregulated DANCR and Bcl- 2 RNA expressions but accelerated cell viability and upregulated Bax, which were enhanced by the overexpression of miR- 577. Hence, DANCR might restrain sensitivity of prostate cancer cells to 5-FU by downregulating miR-577

Targeted fluorescent imaging of a novel FITC-labeled PSMA ligand in prostate cancer

In this study, we synthesized a novel fluorescein isothiocyanate (FITC)-labeled prostate-specific membrane antigen (PSMA) ligand (PSMA-FITC) via the Fmoc solid-phase synthesis method, and the application value of PSMA-FITC in targeted fluorescence imaging of PSMA-positive prostate cancer was evaluated. The PSMA ligand developed based on the Glu-urea-Lys structure was linked to FITC by aminocaproic acid (Ahx) to obtain PSMA-FITC. The new probe was evaluated in vitro and in vivo. Fluorescence microscopy examination of PSMA-FITC in PSMA(+) LNCaP cells, PSMA(−) PC3 cells, and blocked LNCaP cells showed that the binding of PSMA-FITC with PSMA was target-specific. For in vivo optical imaging, PSMA-FITC exhibited rapid 22Rv1 tumor targeting within 30 min of injection, and the highest tumor-background ratio (TBR) was observed 60 min after injection. The TBR was 3.45 ± 0.31 in the nonblocking group and 0.44 ± 0.13 in the blocking group, which was consistent with the in vitro results. PSMA-FITC is a promising probe and has important reference value for the development of PSMA fluorescent probes. In the future, it can be applied to obtain accurate tumor images for radical prostatectomy.

NK Cells Can Preferentially Target Prostate Cancer Stem-like Cells via the TRAIL/DR5 Signaling Pathway

Background: The occurrence of androgen-dependent prostate cancer mainly depends on prostate cancer stem cells. To reduce the risk of androgen-dependent prostate cancer, the direct elimination of prostate cancer stem cells is important, but an elimination strategy has not yet been established. A previous study showed that natural killer (NK) cells can preferentially target cancer stem cells in several solid tumors except prostate cancer. In this context, this study was undertaken to investigate if NK cells can selectively attack androgen-dependent prostate cancer stem cells. Methods: Prostate cancer stem-like cells were separated from an androgen-dependent prostate cancer cell line (LNCaP) using a three-dimensional culture system. LNCaP stem-like cells or LNCaP cells were co-cultured with human NK cells (KHYG-1) for 24–72 h, and cell viability was determined using the WST-8 method. The expression of each protein in the cell membrane was evaluated through FACS analysis, and mRNA levels were determined using real-time PCR. Results: KHYG-1 cells had more potent cytotoxicity against LNCaP stem-like cells than LNCaP cells, and the potency of the cytotoxicity was strongly related to the TRAIL/DR5 cell death pathway. Conclusion: NK cells can preferentially target prostate cancer stem-like cells via the TRAIL/DR5 pathway.

Anti-metastatic effect of GV1001 on prostate cancer cells; roles of GnRHR-mediated Gαs-cAMP pathway and AR-YAP1 axis

Background Gonadotropin-releasing hormone receptor (GnRHR) transmits its signal via two major Gα-proteins, primarily Gαq and Gαi. However, the precise mechanism underlying the functions of Gαs signal in prostate cancer cells is still unclear. We have previously identified that GV1001, a fragment of the human telomerase reverse transcriptase, functions as a biased GnRHR ligand to selectively stimulate the Gαs/cAMP pathway. Here, we tried to reveal the potential mechanisms of which GV1001-stimulated Gαs-cAMP signaling pathway reduces the migration and metastasis of prostate cancer (PCa) cells. Methods The expression of epithelial-mesenchymal transition (EMT)-related genes was measured by western-blotting and spheroid formation on ultra-low attachment plate was detected after GV1001 treatment. In vivo Spleen-liver metastasis mouse model was used to explore the inhibitory effect of GV1001 on metastatic ability of PCa and the transwell migration assay was performed to identify whether GV1001 had a suppressive effect on cell migration in vitro. In order to demonstrate the interaction between androgen receptor (AR) and YAP1, co-immunoprecipitation (co-IP), immunofluorescence (IF) staining, chromatin immunoprecipitation (ChIP) were performed in LNCaP cells with and without GV1001 treatment. Results GV1001 inhibited expression of EMT-related genes and spheroid formation. GV1001 also suppressed in vivo spleen-liver metastasis of LNCaP cells as well as cell migration in vitro. GV1001 enhanced the phosphorylation of AR and transcription activity of androgen response element reporter gene through cAMP/protein kinase A pathway. Moreover, GV1001 increased Ser-127 phosphorylation of YAP1 and its ubiquitination, and subsequently decreased the levels of AR-YAP1 binding in the promoter region of the CTGF gene. In contrast, both protein and mRNA levels of NKX3.1 known for tumor suppressor gene and AR-coregulator were upregulated by GV1001 in LNCaP cells. YAP1 knockout using CRISPR/Cas9 significantly suppressed the migration ability of LNCaP cells, and GV1001 did not affect the cell migration of YAP1-deficient LNCaP cells. On the contrary, cell migration was more potentiated in LNCaP cells overexpressing YAP5SA, a constitutively active form of YAP1, which was not changed by GV1001 treatment. Conclusions Overall, this study reveals an essential role of AR-YAP1 in the regulation of PCa cell migration, and provides evidence that GV1001 could be a novel GnRHR ligand to inhibit metastasis of PCa via the Gαs/cAMP pathway.

Therapeutic Targeting of Histone Lysine Demethylase KDM4B Blocks the Growth of Castration-Resistant Prostate Cancer

Background: Accumulating evidence points to epigenetic mechanisms as essential in tumorigenesis. Treatment that targets epigenetic regulators is becoming an attractive strategy for cancer therapy. The role of epigenetic therapy in prostate cancer (PCa) remains elusive. Previously we demonstrated a correlation of levels of histone lysine demethylase KDM4B with the appearance of castration resistant prostate cancer (CRPC) and identified a small molecular inhibitor of KDM4B, B3. In this study, we aim to define the role of KDM4B in promoting PCa progression and test the efficacy of B3 using clinically relevant PCa models. Methods: KDM4B was overexpressed in LNCaP cells or knocked down (KD) in 22Rv1 cells. The specificity of B3 was determined in vitro using recombinant KDM proteins and in vivo using 22Rv1 cell lysates. The efficacy of B3 monotherapy or in combination with androgen receptor (AR) antagonist enzalutamide or the mTOR inhibitor rapamycin was tested using xenograft models in castrated mice. Comparative transcriptomic analysis was performed on KDM4B KD and B3-treated 22Rv1 cells to determine the on-target (KDM4B-dependent) and off-target (non-KDM4B-associated) effects of B3.Results: Overexpression of KDM4B in LNCaP cells enhanced its tumorigenicity whereas knockdown of KDM4B in 22Rv1 cells reduced tumor growth in castrated mice. B3 suppressed the growth of both 22Rv1 and VCaP xenografts and sensitized 22Rv1 cells to enzalutamide inhibition. B3 also inhibited 22Rv1 tumor growth synergistically with rapamycin that resulted in cell apoptosis. Mechanistically, B3 inhibited expression of AR-V7 and genes involved in epithelial-to-mesenchymal transition. DNA replication stress marker gH2A.X was upregulated by B3, which is further increased when combined with rapamycin. Based on transcriptomic and biochemical analyses, B3 inhibits both H3K9me3 and H3K27me3 demethylase activity, which is believed to underlie its anti-tumor action. Conclusions: Our studies establish KDM4B as a potent target for CRPC and B3 as a potential therapeutic agent. B3 as monotherapy or in combination with other anti-PCa therapeutics offers proof of principle for the clinical translation of epigenetic therapy targeting KDMSs for CRPC patients.

727 Resistance to enzalutamide and abiraterone drives tumor phenotypic plasticity and resistance to immune-mediated cytotoxicity

BackgroundBackground: Treatment of patients with castration-resistant prostate cancer (CRPC) includes the use of next-generation hormonal therapies such as abiraterone or enzalutamide. Although these agents extend survival, a significant proportion of patients exhibit primary or acquired resistance to treatment. In recent years, immune checkpoint blockade has led to remarkable responses in patients with several tumor types, however, CRPC has remained resistant to immunotherapy. Previous studies have demonstrated that different tumor variants could emerge along the progression of prostate cancer, including tumors undergoing phenotypic plasticity in the context of an epithelial-mesenchymal transition. Our laboratory and others have shown that phenotypic plasticity is a driver of resistance to immunotherapy. Based on this knowledge, we investigated whether changes in tumor phenotype could affect the response of CRPC to immune-based therapies, and ways this can be mitigated.MethodsThe androgen sensitive LNCAP prostate cancer cell line was used to derive LNCAP cells resistant to enzalutamide (LNCAP-EnzaR) or abiraterone (LNCAP-AbiR). Resistant cell lines and parental LNCAP cells were comparatively evaluated for features of EMT and neuroendocrine phenotype via RT-PCR, ELISA, western blot, immunofluorescence, and RNAseq. Changes in the susceptibility to NK-cell mediated cytotoxicity were evaluated with NK cells isolated from peripheral blood from healthy donors. LNCAP-EnzaR cells were also grown in vivo in NSG MHC-deficient mice, and tumors were characterized for phenotypic markers and potential therapeutic targets.ResultsAcquisition of resistance to both enzalutamide and abiraterone was associated with a significant increase in mesenchymal tumor features, including high levels of vimentin and fibronectin, and the loss of epithelial features and cell-to-cell attachments. LNCAP-Enza-R and LNCAP-AbiR cells showed a significant reduction (up to 90%) in susceptibility to NK-cell mediated cytotoxicity and antibody-dependent cell cytotoxicity (ADCC), compared with parental cells. These results prompted us to investigate approaches to improve immune-mediated lysis, including inhibition of estrogen receptor 1 (ESR1), which was identified as highly upregulated in LNCAP-EnzaR cells via RNAseq analysis. In a xenograft model of LNCAP-EnzaR cells, we corroborated the maintenance of tumor phenotypic plasticity and the expression of actionable targets.ConclusionsOur data indicates that acquisition of resistance to androgen receptor inhibition is associated with marked reduction of susceptibility to immune attack, and the acquisition of tumor phenotypic plasticity. Future studies will investigate approaches that revert tumor plasticity, including blockade of ESR1, TGF-beta or IL-8, for potential improvement of tumor susceptibility to immune attack in CRPC.Ethics ApprovalPBMCs were obtained from healthy donors at the NIH Clinical Center Blood Bank (NCT00001846). All animal studies were approved and conducted in accordance with an IACUC-approved animal protocol (LTIB-57) with the approval the NIH/NCI Institutional Animal Care and Use Committee.

Functionalized Silver Nanoparticles Enhance Therapeutic Effect of Paclitaxel for Prostate Cancer Therapy by Arresting the Cellular Cycle and Producing ROS

Chemotherapy has been proven to be an efficient strategy for the treatment of prostate cancer (PC). However, the insufficient cellular uptake of drugs is the biggest challenge for PC therapy. Therefore, in order to address the above concern, we developed tumor-targeted hyaluronic acid-silver nanoparticles (HA-Ag NPs), in which hyaluronic acid can specially bind with its receptor CD44 overexpressed on LNCaP cells. HA-Ag NPs have been used to load paclitaxel (PTX) to prepare functionalized silver nanoparticles (HA-Ag-PTX). The average particle size of HA-Ag-PTX was about 70 nm and kept under 120 nm for eight days. androgen-sensitive prostate cancer cells (LNCaP) cells show good uptake of HA-Ag-PTX, and HA-Ag-PTX enters LNCaP cells in a clathrin-mediated energy-dependent manner. HA-Ag-PTX exhibits an excellent pH response release of PTX under the acidic condition, which is beneficial to enhance the distribution of PTX in the tumor microenvironment. HA-Ag-PTX effectively suppresses the migration and proliferation of LNCaP cells probably by arresting the cellular cycle at [Formula: see text]0/[Formula: see text]1 phase and enhancing the production of the reactive oxygen species. It is worth mentioning that HA-Ag-PTX exhibits greater anticancer activity in comparison with free PTX in the LNCaP cell model, indicating that HA-Ag NPs can effectively enhance the anticancer efficacy of PTX. As a whole, these findings suggest that HA-Ag-PTX has promising potential for PC therapy.