Human Prostate Carcinoma PC-3 Cells Research Articles

Proteomic profiling identifies a direct interaction between heat shock transcription factor 2 and the focal adhesion adapter talin-1.

Heat shock factor 2 (HSF2) is a versatile transcription factor that regulates gene expression under stress conditions, during development, and in disease. Despite recent advances in characterizing HSF2-dependent target genes, little is known about the protein networks associated with this transcription factor. In this study, we performed co-immunoprecipitation coupled with mass spectrometry analysis to identify the HSF2 interactome in mouse testes, where HSF2 is required for normal sperm development. Endogenous HSF2 was discovered to form a complex with several adhesion-associated proteins, a finding substantiated by mass spectrometry analysis conducted in human prostate carcinoma PC-3 cells. Notably, this group of proteins included the focal adhesion adapter protein talin-1 (TLN1). Through co-immunoprecipitation and proximity ligation assays, we demonstrate the conservation of the HSF2-TLN1 interaction from mouse to human. Additionally, employing sequence alignment analyses, we uncovered a TLN1-binding motif in the HSF2 C terminus that binds directly to multiple regions of TLN1 in vitro. We provide evidence that the 25 C-terminal amino acids of HSF2, fused to EGFP, are sufficient to establish a protein complex with TLN1 and modify cell-cell adhesion in human cells. Importantly, this TLN1-binding motif is absent in the C-terminus of a closely related HSF family member, HSF1, which does not form a complex with TLN1. These results highlight the unique molecular characteristics of HSF2 in comparison to HSF1. Taken together, our data unveil the protein partners associated with HSF2 in a physiologically relevant context and identifies TLN1 as the first adhesion-related HSF2-interacting partner.

In vitro study on the anticancer effects of oxalipalladium against PC3 human prostate carcinoma cells

Prostate cancer is a common type of cancer in men with high incidence and mortality. Our aim was to investigate the effects of oxalipalladium (ox-Pd) on metastatic human prostate cancer PC3 cells and compare them with the effects of oxaliplatin (ox-Pt) (as an approved cancer drug). We synthesized ox-Pd through a new chemical method and used FT-IR, 1H NMR, 13C NMR, and MS analyzes to characterize it. The effects of ox-Pd on PC3 cells viability, apoptosis, cell cycle, migration, and gene expression were examined. Inhibition of topoisomerase IIα activity was investigated by pHOT1 plasmid relaxation and kDNA decatenation assays. Chemical tests showed ox-Pd with the correct composition and structure. For the first time, the exact fragmentation pathway of ox-Pd and its difference with ox-Pt was obtained by MS analysis. Ox-Pd significantly decreased PC3 cell viability with less/no toxicity effect on MHFB-1 normal skin fibroblasts. Wound scratch assay confirmed the strong anti-migratory activity of ox-Pd. According to flow cytometry analysis, this drug increased the number of PC3 cells in late apoptosis and decreased DNA replication and mitosis. Furthermore, pHOT1 plasmid relaxation and kDNA decatenation assays showed that ox-Pd strongly inhibited the catalytic activity of topoisomerase IIα. The expression of topoisomerase IIα, Bcl-2, P21, and survivin was decreased while the expression of Bax and p53 was increased under ox-Pd treatment. We provide the first evidence that ox-Pd exhibits more selective anticancer effects on PC3 cells compared to ox-Pt. Taken together, these data strongly suggest a therapeutic window for ox-Pd in cancer.

Anticancer Effect of Hemin through ANO1 Inhibition in Human Prostate Cancer Cells.

Anoctamin1 (ANO1), a calcium-activated chloride channel, is overexpressed in a variety of cancer cells, including prostate cancer, and is involved in cancer cell proliferation, migration, and invasion. Inhibition of ANO1 in these cancer cells exhibits anticancer effects. In this study, we conducted a screening to identify novel ANO1 inhibitors with anticancer effects using PC-3 human prostate carcinoma cells. Screening of 2978 approved and investigational drugs revealed that hemin is a novel ANO1 inhibitor with an IC50 value of 0.45 μM. Notably, hemin had no significant effect on intracellular calcium signaling and cystic fibrosis transmembrane conductance regulator (CFTR), a cyclic AMP (cAMP)-regulated chloride channel, and it showed a weak inhibitory effect on ANO2 at 3 μM, a concentration that completely inhibits ANO1. Interestingly, hemin also significantly decreased ANO1 protein levels and strongly inhibited the cell proliferation and migration of PC-3 cells in an ANO1-dependent manner. Furthermore, it strongly induced caspase-3 activation, PARP degradation, and apoptosis in PC-3 cells. These findings suggest that hemin possesses anticancer properties via ANO1 inhibition and could be considered for development as a novel treatment for prostate cancer.

Prostate Cancer Therapy Using Docetaxel and Formononetin Combination: Hyaluronic Acid and Epidermal Growth Factor Receptor Targeted Peptide Dual Ligands Modified Binary Nanoparticles to Facilitate the in vivo Anti-Tumor Activity.

ObjectiveTo evaluate the prostate cancer therapy efficiency of the synergistic combination docetaxel (DTX) and formononetin (FMN) in one nano-sized drug delivery system. Hyaluronic acid (HA) and epidermal growth factor receptor-targeted peptide (GE11) dual ligands were applied to modify the nano-systems.MethodsIn this study, GE11-modified nanoparticles (GE-NPs) were applied for the loading of DTX, and HA-decorated NPs (HA-NPs) were used to encapsulate FMN. HA and GE11 dual ligand-modified binary nanoparticles (HAGE-DTX/FMN-NPs) were constructed by the self-assembling of GE-NPs and HA-NPs. The anti-PCa ability of the system was evaluated in vitro on PC-3 human prostate carcinoma cells (PC3 cells) and in vivo on PC3 tumor-bearing mice in comparison with single NPs and free drugs formulations.ResultsHA/GE-DTX/FMN-NPs were nano-sized particles with smaller particles coating on the inner core and achieved a size of 189.5 nm. HA/GE-DTX/FMN-NPs showed a cellular uptake efficiency of 59.6%, and a more efficient inhibition effect on PC3 cells compared with single ligand-modified NPs and free drugs. HA/GE-DTX/FMN-NPs showed significantly higher tumor inhibition efficiency than their single drug-loaded counterparts and free drugs.ConclusionHA/GE-DTX/FMN-NPs have a synergistic anti-tumor effect and also could the reduce unexpected side effects during the cancer therapy. It could be used as a promising anti-PCa system.

Evaluation of different internal standardization approaches for the quantification of melatonin in cell culture samples by multiple heart-cutting two dimensional liquid chromatography tandem mass spectrometry

We evaluate here different analytical strategies for the chromatographic separation and determination of N-acetyl-5-methoxytryptamine (MEL) and its oxidative metabolites N1-acetyl-N2-formyl-5-methoxykynuramine (AFMK), N1-acetyl-5-methoxykynuramine (AMK) and cyclic 3-hydroxymelatonin (c3OHM) in cell culture samples. Two dimensional liquid chromatography (2D-LC) in the multiple heart-cutting mode was compared with regular 1D chromatographic separations of MEL and its oxidative metabolites. Our results showed that the use of trifluoroacetic acid (TFA) as mobile phase modifier was required to obtain a satisfactory resolution and peak shapes particularly for c3OHM. As TFA is not compatible with ESI ionization the application of the MHC mode was mandatory for a proper chromatographic separation. We evaluate also different internal standardization approaches based on the combined use of a surrogate standard (5-methoxytryptophol) and an internal standard (6-methoxytryptamine) for MEL quantification in cell culture samples obtaining unsatisfactory results both by 1D- and 2D-LC-ESI-MS/MS (from 9 ± 2 to 186 ± 38%). We demonstrate that only the application of isotope dilution Mass Spectrometry through the use of an in house synthesized 13C isotopically labelled analogue provided quantitative MEL recoveries both by using 1D- and 2D-LC-ESI-MS/MS (99±1 and 98±1. Respectively) in androgen-insensitive human prostate carcinoma PC3 cells.

The anticancer activity of chalcone compounds against human prostate carcinoma cell and human colon colorectal adenocarcinoma

The anticancer activities 3-(substituted phenyl)-1-[4-(morpholine-4-yl)phenyl]prop-2-en-1-one derivatives were investigated against PC3 (Human Prostate Carcinoma Cell) and HT29 (Human colon colorectal adenocarcinoma) cell lines. The anticancer activity tests were performed by the BrdU ELISA method. 5-Fluorouracil (5-FU) was used as standard compound. Compound 1-7 (except Compound 3) were determined to have higher anticancer activity than 5-FU aganist PC3 cancer cells. IC50 values of the Compounds 1-7 against PC3 cancer cells were 2.53±0.02 µM; 4.40±0.03 µM; 4.36±0.03 µM; 1.76±0.02 µM; 1.78±0.03 µM; 2.31±0.03 µM, respectively.

Cytotoxic bafilomycin analogues 6/5/5 with tricyclic ring system from a marine-derived Streptomyces sp

Two bafilomycin derivatives with an unprecedented 6/5/5 tricyclic ring system (1 and 2), along with five known analogues (3–7), were identified from a marine Streptomyces sp. The structures of 1 and 2 were elucidated by analysis of HRESIMS, extensive NMR spectroscopic methods, GIAO DET 13C NMR calculations and comparison of the spectroscopic data with those of known related compounds. Compound 2 exhibited significant cytotoxicity against PC3 human prostate carcinoma cells with IC50 value of 4.99 ± 0.15 μM.

Abstract 770: MiR628-5p targets Jagged 1 and inhibits growth, stemness and invasiveness of advanced prostate cancer cells

Abstract Prostate cancer (PCa) is the most common non-cutaneous cancer in men, and according to the American Cancer Society reports, 164,690 new cases and 29,430 deaths from PCa are estimated in the United States in 2018. To reduce PCa mortality, we need a better understanding of molecular regulators of prostate carcinogenesis. MicroRNAs (MiRs) are small, non-coding RNA molecules that have been implicated in various cancers, and offer a novel opportunity to diagnose and treat cancer. We have previously identified MiR628-5p as a potential biomarker in PCa patients. This miRNA was found to be downregulated in the serum of both African American and Caucasian men with PCa compared to healthy individuals. In the present study, we further characterized the anti-cancer role of MiR628-5p in various PCa cell culture models. Results showed that MiR628-5p mimic treatment (100 nM) for 5 days significantly decreased the cell proliferation (~43% inhibition, p<0.001) in human prostate carcinoma PC3 cells compared to random mimic control. Similarly, MiR628-5p mimic treatment decreased the number of clones (clone size ≥50 cells) formed by PC3 cells by 40% (p<0.001) compared to random mimic control. Interestingly, miRNA 628-5p mimic treatment also reduced the stemness of PC3 cells as reflected in significant decrease in prostasphere size and CD44 expression. In mechanistic studies, we identified Jagged-1 as a molecular target regulated by MiR628-5p. MiR628-5p mimic treatment strongly decreased the Jagged-1 expression in several PCa cell lines (PC3, DU145, LNCaP and C4-2) as well as reduced the Jagged-1 luciferase activity. Jagged 1 inhibition by MiR628-5p was associated with reduced Notch signaling as well as decreased expression of transcription factors (snail and slug) regulating EMT. Moreover, MiR628-5p mimic treatment increased the expression of epithelial biomarkers (E-cadherin and ZO1), reduced the expression of mesenchymal marker (vimentin) and strongly inhibited the invasiveness of PC3 cells. In conclusion, we present evidence that MiR628-5p is a key regulator of prostate carcinogenesis, and offers a novel therapeutic opportunity to inhibit the growth of advanced PCa. Citation Format: Leslimar Rios-Colon, Juliet Chijioke, Anvesha Srivastava, Malathi Ramalinga, Habib Kedir, Elena Arthur, Patrice Cagle, Gagan Deep, Deepak Kumar. MiR628-5p targets Jagged 1 and inhibits growth, stemness and invasiveness of advanced prostate cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 770.

Folate-Decorated Amphiphilic Cyclodextrins as Cell-Targeted Nanophototherapeutics.

Nowadays, active targeting of nanotherapeutics is a challenging issue. Here, we propose a rational design of a ternary nanoassembly (SAP) composed of nonionic amphiphilic β-cyclodextrins (amphiphilic CD) incorporating pheophorbide (Pheo) as a phototherapeutic and an adamantanyl-folic acid conjugate (Ada-FA) to target tumor cells overexpressing α-folate receptor (FR-α(+)). Dynamic light scattering and ζ-potential pointed out the presence of nanoassemblies bearing a negative surface charge (ζ = -51 mV). Morphology of SAP was investigated by atomic force microscopy and microphotoluminescence, indicating the presence of highly emissive near-spherical assemblies of about 280 nm in size. Complementary spectroscopic techniques such as ROESY-NMR, UV/vis and steady-state fluorescence revealed that the folic acid protrudes out of amphiphilic CD rims, prone for recognition with FR-α. Pheo was strongly loaded in the nanoassembly mostly in monomeric form, thus generating singlet oxygen (1O2) and consequentely showing phototherapeutic action. SAP remained stable until 2 weeks in aqueous solutions. Stability studies in biologically relevant media pointed out the ability of SAP to interact with serum proteins by means of the oligoethylenglycole fringe, without destabilization. Release experiments demonstrated the sustained release of Pheo from SAP in environments mimiking physiological conditions (∼20% within 1 week), plausibly suggesting low Pheo leaking and high integrity of the assembly within 24 h, time spent on average to reach the target sites. Cellular uptake of SAP was confirmed by confocal microscopy, pointing out that SAP was internalized into the tumoral cells expressing FR-α more efficiently than SP. SAP showed improved phototoxicity in human breast MCF-7 cancer cells FR-α(+) (IC50 = 270 nM) with respect to human prostate carcinoma PC3 cells (IC50 = 700 nM) that express a low level of that receptor (FR-α(-)). Finally, an improved phototoxicity in FR-α(+) MCF-7 cells (IC50 = 270 nM) was assessed after treatment with SAP vs SP (IC50 = 600 nM) which was designed without Ada-FA as a targeting unit.

Chemotherapeutic Effect of CD147 Antibody-labeled Micelles Encapsulating Doxorubicin Conjugate Targeting CD147-Expressing Carcinoma Cells.

CD147 (basigin/emmprin) is expressed on the surface of carcinoma cells. For studying the efficacy of CD147-targeting medicine on CD147-expressing cells, we studied the effect of anti-CD147-labeled polymeric micelles (CD147ab micelles) that encapsulated a conjugate of doxorubicin with glutathione (GSH-DXR), with specific accumulation and cytotoxicity against CD147-expressing A431 human epidermoid carcinoma cells, Ishikawa human endometrial adenocarcinoma cells, and PC3 human prostate carcinoma cells. By treatment of each cell type with CD147ab micelles for 1 h, a specific accumulation of CD147ab micelles in CD147-expressing cells was observed. In addition, the cytotoxicity of GSH-DXR-encapsulated micelles against each cell type was measured by treatment of the micelles for 1 h. The cytotoxic effect of CD147ab micelles carrying GSH-DXR was 3- to 10-fold higher for these cells than that of micelles without GSH-DXR. These results suggest that GSH-DXR-encapsulated CD147ab micelles could serve as an effective drug delivery system to CD147-expressing carcinoma cells.

Potential anticancer activity of biogenic silver nanoparticles using leaf extract of Rhynchosia suaveolens: an insight into the mechanism

The present study reports a simple and eco-friendly synthesis of silver nanoparticles (AgNPs) using leaf extract of Rhynchosia suaveolens. UV-Vis analysis of R. suaveolens synthesized AgNPs (RS-AgNPs) showed surface plasmon resonance (SPR) peak at 426 nm. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) analysis revealed that RS-AgNPs were 10–30 nm in size with spherical shape. X-ray diffraction (XRD) analysis of RS-AgNPs confirmed the crystalline nature with face-centered cubic (FCC) lattice. Fourier transform infrared (FTIR) interprets that polyphenols and proteins take part in bioreduction and capping of RS-AgNPs. RS-AgNPs exhibited dose-dependent inhibition of proliferation of different cancer cells including DU145 and PC-3(human prostate carcinoma cell lines), SKOV3 (human ovarian carcinoma) and A549 (human lung adenocarcinoma)with IC50 values of 4.35, 7.72, 4.2 and 24.7 μg/mL, respectively. The plausible reasons behind anticancer activity of RS-AgNPs were explained using different assays on the most susceptible SKOV3 cells. RS-AgNPs induced oxidative stress in SKOV3 cells by generating reactive oxygen species (ROS), enhancing lipid peroxidation (LPO) levels and decreasing glutathione (GSH) levels. RS-AgNPs induced the apoptosis of SKOV3 cells by up regulating the caspase-3, caspase -8, caspase -9, p53 and BAX and down regulating the antiapoptotic protein Bcl-2. Further, RS-AgNPs showed elevation of caspase 3/7 activity and also exhibited antimigratory effect by inhibiting the migration of SKOV3 cells into the wounded area. The findings suggested that biogenic RS-AgNPs provide an alternative approach to overcome several limitations of chemotherapy.

Effect of Levisticum officinale Hydroalcoholic Extract on DU-145 and PC-3 Prostate Cancer Cell Lines

: Levisticum officinale contains a variety of components used for its medicinal properties in traditional medicine. The previous studies showed that it had an anti-cancer effect on cell lines. The current study aims to evaluate the cytotoxic potential of Levisticum officinale hydroalcoholic extract (LOHE) on DU-145 and PC-3 human advanced prostate cancer cell lines. The anti-proliferative activity of LOHE was evaluated using the MTT assay. The results of MTT showed that the IC50 of DU-145 and PC-3 were 500 µg/mL and 400 µg/mL of LOHE, respectively, following 24 hours treatment. This study found that the hydroalcoholic extract of Levisticum officinale had beneficial cell death inducing effects on both the PC3 and DU145 human prostate carcinoma cell lines in time- and concentration-dependent fashion. Hence, LOHE may have remarkable potential for uses as new natural anticancer agent.

Lysophosphatidylcholine elicits intracellular calcium signaling in a GPR55-dependent manner

The GPR55 signaling is fertile ground for drug discovery, however despite considerable research progress during the past 10 years, many open questions remain. The GPR55 pharmacology remains controversial, as many ligands have been reported with inconsistent results. Here, we show that various molecular species of lysophosphatidylcholine (LPC) elicit intracellular Ca2+ mobilization in GPR55-expressing PC-3 human prostate carcinoma cells. The response was even stronger than [Ca2+]i flux evoked by endogenous (OEA) and synthetic (Abn-CBD) agonists. Treatment with GPR55 antagonists CID16020046 and ML193 as well as the lipid raft disrupter methyl-β-cyclodextrin strongly blunted LPC-induced calcium signal. Additionally, molecular modeling analysis revealed that LPC 16:0 and LPC 18:1 interact stronger with the receptor than to OEA. Identified electrostatic interactions between GPR55 residues and the ligands overlap with the binding site identified previously for lysophosphatidylinositol. Therefore, we prove that LPC is another GPR55-sensitive ligand. This finding is relevant in understanding lysophospolipids-mediated signaling and opens new avenues to develop therapeutic approach based on GPR55 targeting.

Effect of silencing sperm associated antigen 9 gene specially by RNA interference on human prostate carcinoma PC-3 cells

Objective To investigate the effect of silencing sperm associated antigen 9 (SPAG9) gene specially by RNA interference on human prostate carcinoma PC-3 cells, and the possible mechanism. Methods The plasmid vector expressing SPAG9 short hairpin RNA (shRNA) was constructed and transfected into PC-3 cells by lipofectamine 2000. Cells were collected and assayed at 48 h after transfection. The SPAG9 mRNA and protein expression level was measured by reverse transcriptase-polymerase chain reaction (RT-PCR) and Western blotting, respectively. Cell proliferation was tested by cell counting kit-8 (CCK-8) assay. Cell apoptosis was detected by fluorescence-activated cell sorter (FACS). The invasion ability of cells was examined by Transwell assay. To explore its possible mechanism, the expression of matrix metalloproteinase (MMP)-2, vascular endothelial growth factor (VEGF), Vimentin and E-cadherin proteins was measured by Western blotting after SPAG9 gene knockdown for 48 h. Results The recombinant plasmid pGPU6-green fluorescent protein (GFP)-SPAG9 expressing SPAG9 shRNA had been constructed successfully. RT-PCR and Western blotting showed the expression level of SPAG9 mRNA and proteinin in pGPU6-GFP-SPAG9 group was 1.96±0.16 and 0.39±0.05 respectively, lower than empty plasmid group (3.23±0.18 and 1.13±0.04), blank control group (3.08±0.12 and 1.25±0.05), respectively, the differences were both statistically significant (P=0.000). The absorbance (A) value was 31.9±2.6 in pGPU6-GFP-SPAG9 group, weaken than that in empty plasmid group (47.8±2.8, P=0.023), blank control group (48.1±2.8, P=0.016), the differences were statistically significant. FACS analysis showed that the apoptosis rate was (12.12±0.69)% in pGPU6-GFP-SPAG9 group, more than empty plasmid group [(6.43±0.31)%, P=0.020], blank control group [(5.19±0.33)%, P=0.014], the differences were statistically significant. Western blotting showed the expression level of MMP-2, VEGF, and Vimentin in pGPU6-GFP-SPAG9 group was lower than in the control groups, however, the average expression level of E-cadherin in pGPU6-GFP-SPAG9 group was higher than in the control groups, the differences were all statistically significant (P=0.000). Conclusion Silencing SPAG9 gene can inhibit SPAG9 gene expression, suppress proliferation, induce cell apoptosis of PC-3 cells by decreasing MMP-2, VEGF and Vimentin expression level, and increasing E-cadherin expression level. Key words: Prostate cancer; Sperm associated antigen 9 gene; RNA interference

Phthalate induced toxicity in prostate cancer cell lines and effects of alpha lipoic acid.

The effects of dimethyl phthalate, diethyl phthalate, diisobutyl phthalate, di-n-butyl phthalate, benzylbutyl phthalate, di-2-ethylhexyl phthalate were investigated on human prostate cancer cell lines DU145 and PC3 in vitro. Standards of dimethyl phthalate, diethyl phthalate, di-isobutyl phthalate, dibutyl phthalate, benzyl butyl phthalate, and di-ethyl hexyl phthalate were used. Alpha lipoic acid was used as antioxidant compound. DU145 and PC3 human prostate carcinoma cells were used. MTT assay were used for cytotoxicity assay. A low dose proliferative effect of phthalates in vitro was observed. With the hypothesis of the inhibition of aerobic glycolysis activity in cancer treatment, α-lipoic acid was applied to cells; where as a contrary to previous studies, no change in the cell proliferation was observed. In combination with ALA, at IC50 and lower doses, an increase of the cytotoxic effect was found for DIBP, DBP and BBP; while for DMP, DEP and DEHP, a decrease was observed for DU145 cells. In PC3 cells, a decrease was observed for DMP, DEP and DBPs; while no significant difference were observed for DEHP, DIBP and BBP. The present study demonstrates preliminary information regarding the low dose proliferative effects of phthalates in prostate cancer in vitro (Tab. 2, Fig. 2, Ref. 65).

Abstract 4626: In-vitro growth inhibitory effects of diosmetin on human prostate cancer cells

Abstract Characterization of effective chemo-preventive agents for treatment of prostate cancer is an utmost priority. Diosmetin (5, 7-Trihydroxy-4′-methoxyflavone), a natural flavonoid present in citrus plant, has anti-mutagenic and anti-allergic properties. However, the anticancer properties of diosmetin have not been explored in prostate cancer. Present study demonstrates, cell growth inhibition and induction of apoptosis in human prostate carcinoma LNCaP (androgen-responsive) and PC-3 (androgen-refractory) cells by diosmetin, however, no significant growth inhibition observed in normal prostate epithelial cells (RWPE1). Cell growth is a fundamental biological process, where mTOR (mammalian target of rapamycin) pathway has its role, regulates cell growth by coordinating energy and nutrient signals with growth factor. mTOR protein kinase have two different complexes; complex-I contains major component raptor; a target of rapamycin and complex II; insensitive to rapamycin, has major component rictor. Rictor is important as it phosphorylates Ser-473 of Akt/PKB, which is essential for full Akt/PKB activation. We observed diosmetin treated prostate cancer cells was able to inhibit growth factor (IGF-1) and cytokine (IL-6) induced rictor expression. Furthermore, diosmetin (20μM) treatment to prostate cancer cells prevented rictor nuclear localization and subsequently inhibited phospho-Akt (Ser-473), which subsequently resulted in increased FOXO3a nuclear presence. Downstream pathway p70S6 kinase, which has a critical role in cell cycle, growth and survival, was also inhibited after diosmetin treatment. These effects were associated with a marked decrease in the protein expression of cyclin D1 and their activating partner, cyclin-dependent kinase (cdk) 2 and 4 with concomitant upregulation of KIP1/p27 and INK4a/p16. Additionally diosmetin treatment to these cells modulated cell survival machinery by down regulating key molecules viz., c-Myc, Survivin and XIAP (X-Linked Inhibitor of Apoptosis). Diosmetin treatment also resulted in alteration in Bax/Bcl2 ratio in favor of apoptosis, which was associated with an increase in cleaved caspase-3. Taken together, our studies demonstrate that diosmetin-mediated growth inhibition and induction of apoptosis in both LNCaP and PC-3 cells were due to deregulated levels of rictor and Akt signaling cascade and modulation of cell-cycle machinery. We are documenting these evidences for the first time that diosmetin acts against potential molecular targets to alter cellular events to elicit anticancer effects in prostate cancer cells. Citation Format: Rebecca Pakradooni, Riddhi Patel, Janmejai K. Srivastava, Sanjeev Shukla. In-vitro growth inhibitory effects of diosmetin on human prostate cancer cells. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4626.

Dual Stimuli-Responsive Hybrid Polymeric Nanoparticles Self-Assembled from POSS-Based Starlike Copolymer-Drug Conjugates for Efficient Intracellular Delivery of Hydrophobic Drugs.

To further fine tune drug release and enhance therapeutic effects of polyhedral oligomericsilsesquioxane (POSS)-based nanomedicine, a starlike organic-inorganic conjugate was synthesized by grafting semitelechelic N-(2-hydroxypropyl) methacrylamide (HPMA) copolymers to a POSS rigid core through reductively degradable disulfide bonds. The hydrophobic docetaxel (DTX) was attached to the grafts by pH-sensitive hydrazone bonds and also encapsulated into the POSS core (SP-DTX). Thus, the final amphiphilic star-shaped conjugates could self-assemble into nanoparticles and exhibited conspicuous drug-loading capacity (20.1 wt %) based on the covalently conjugated accompanied by physically encapsulated DTX. The stimuli-responsive DTX release under acidic lysosomal and reducing cytoplasmic environments was verified, leading to enhanced cytotoxicity against PC-3 human prostate carcinoma cells. To evaluate the in vivo therapeutic effects of the DTX-loaded nanovehicles objectively, a stroma-rich, prostate xenograft tumor model was generated. SP-DTX displayed uniform tumor distribution and suppressed tumor growth to a more pronounced level (tumor inhibition of 78.9%) than nonredox-sensitive SP-DTX-A (67.4%), SP-DTX-C contained DTX only in the core (65.5%) or linear P-DTX (60.7%) through enhanced depletion of cancer-associated fibroblasts and induction of apoptosis. The hybrid POSS-based polymeric nanoparticles offer an efficient approach to transport hydrophobic drugs for cancer therapy.

Peptide-conjugated nanoparticles for targeted imaging and therapy of prostate cancer

While there has been extensive development of anti-cancer drugs for treatment of prostate cancer, the therapeutic efficacy of such drugs remains inadequate in many cases. Here, we performed in vitro biopanning of the PC3 human prostate carcinoma cell line to select prostate cancer-specific peptides by phage display. We successfully identified specific peptides targeting prostate cancer cells, and their specificity was confirmed by cellular ELISA and flow cytometry. Moreover, we found that the phage clones also recognize other prostate cancer cell lines and surgical specimens from prostate cancer patients. The tumor targeting ability of these phages was validated in a xenograft model, in which high accumulation of targeting phage was observed. To investigate whether selected peptides are able to target tumors and enhance drug delivery into cancer cells, we synthesized peptide-PEGylated lipids and post-inserted them into preformed liposomal doxorubicin and vinorelbine. The results of our cellular uptake and MTT assays indicate that peptide-conjugated liposomes exhibit enhanced drug intracellular delivery and cytotoxicity. The conjugation of targeting peptide to imaging agents, such as quantum dots (QDs) and superparamagnetic iron oxide nanoparticles (SPIONs), results in more precise delivery of these agents to tumor sites. Furthermore, administration of liposomal doxorubicin and vinorelbine conjugated with targeting peptides was found to markedly increase the inhibition of human prostate tumor growth in mouse xenograft and orthotopic models. These results indicate that targeting peptide, SP204, has significant potential for targeted therapy and molecular imaging in prostate cancer.

Docetaxel prodrug liposomes for tumor therapy: characterization, in vitro and in vivo evaluation

There is a strong desire to develop docetaxel (DTX) formulation with good therapeutic effectiveness in view of serious adverse reactions of the commercial formulation of DTX (Taxotere®). In this study, a redox-responsive DTX-vitamin E prodrug was successfully formulated into liposomes with the drug loading of 4.14% ± 0.10%. Compared with DTX liposomes, the DTX prodrug liposomes (DPLs) showed good stability for 30-d shelf life and during dilution with different media. In vitro antitumor activity of DPLs on human prostatic carcinoma PC-3 cells and human lung cancer A549 cells was evaluated using cytotoxicity and apoptosis assays. In spite of a decrease in in vitro antitumor activity, the in vivo pharmacokinetic study reveals that DPLs exhibit significantly longer DTX plasma half-life (t1/2, 1.38-fold) and higher bioavailability (AUC0−t, 14.49-fold) compared with DTX liposomes. The antitumor activity of DPLs to the A549 tumor xenograft model showed selective accumulation in tumor tissue, significant inhibition the growth of the tumors and a much lower toxicity as seen in body weight loss, compared with DTX-Solution. Taken together, the results showed that DPLs is a promising strategy for DTX antitumor delivery.

(5Z,11Z,15R)-15-Hydroxyeicosa-5,11-dien-13-ynoic acid: A stable isomer of 15(S)-HETE that retains key vasoconstrictive and antiproliferative activity

15(S)-Hydroxyeicosa-(5Z,8Z,11Z,13E)-tetraenoic acid (15(S)-HETE) is a metabolite of arachidonic acid that elicits a number of biological effects including vasoconstriction and angiogenesis. (5Z,11Z,15R)-15-Hydroxyeicosa-5,11-dien-13-ynoic acid (HETE analog 1) is a synthetic isomer of 15(S)-HETE that is much more stable to autoxidation. Using isometric recording of isolated pulmonary arteries from male and female rabbits, HETE analog 1 and 15(S)-HETE were found to elicit concentration-dependent contractions that were slightly greater in females compared to males. The maximal response in females was greater with 15(S)-HETE. HETE analog 1 and 15(S)-HETE increased [3H]-thymidine incorporation in vascular smooth muscle cells cultured from male rabbit pulmonary arteries; both the maximal response and potency were greater with 15(S)-HETE. In contrast, HETE analog 1 produced a concentration-dependent inhibition in proliferation and migration of human hormone-independent prostate carcinoma PC-3 cells. The protocol for synthesis of HETE analog 1 is reported. The stability of this substance and its similar biological profile to 15(S)-HETE support future studies in eicosanoid research.