Differentiation of androgen-independent prostate cancer PC-3 cells is associated with increased nuclear factor-kappaB activity

Upregulated histone deacetylase 2 gene correlates with the progression of oral squamous cell carcinoma

BACKGROUND

Histone deacetylases (HDACs) are considered as an essential regulator of cellular proliferation, differentiation, and apoptosis. The HDAC2 enzyme of Class I HDACs plays an important role in tumor progression of human malignancies.

OBJECTIVE

The aim of the present study was to analyze the HDAC2 gene expression in pre-oral cancer and oral squamous cell carcinoma (OSCC), and its association with clinico-pathological features.

METHODS

The HDAC2 protein expression was analyzed through the immunohistochemistry and western blot techniques in 82 oral pre-malignant, 90 OSCC, and 16 normal control tissues. qRT-PCR was used to quantify the mRNA fold change in all groups.

RESULTS

The HDAC2 protein and mRNA levels were significantly higher in OSCC and pre-oral cancer groups compared to the controls. Immunostaining of HDAC2 protein was enhanced in 84.4% of OSCC and 67.1% of pre-cancerous tissue sections (p< 0.01). The mean protein level was analyzed as 1.96 ± 0.44 in oral carcinoma, 1.61 ± 0.39 in pre-cancer and 0.96 ± 0.10 in control tissues. In addition, HDAC2 mean protein level was associated with histological differentiation (OR = 25, p< 0.05) and tumor-node-metastasis (TNM) stages (OR = 6.2, p< 0.05) of OSCC patients.

CONCLUSIONS

The upregulated HDAC2 gene in pre-cancer and OSCC tissues indicates its crucial role in the transformation of pre-malignant to malignant carcinoma. It could be a potential cancer biomarker of prognosis and targeted therapy in OSCC.

New transcription factors involved with postnatal ventral prostate gland development in male Wistar rats during the first week

AIMS

The high incidence in men of prostatic diseases, including benign and malignant tumors, makes the understanding of prostate development and biology very important. Understanding the organogenesis of the prostate gland has been a substantial challenge as "prostatic code" is not well defined at the present time. The novelty of this work lies in unveiling new transcription factors (TFs) during neonatal ventral prostate (VP) gland development in male Wistar rats.

MAIN METHODS

The techniques of qRT-PCR and immunohistochemistry have been employed to perform this work while the VP gland was obtained from neonatal rats at day zero (the day of birth) day 3 and 6.

KEY FINDINGS

16 TFs were studied and we found an increased expression of Eya2, Lhrh and Znf142, invariable levels of Znf703 and Dbp, and decreased expression of 11 others at postnatal development day 3 and 6 as compared to day zero. ZNF703 was found by immunohistochemistry in epithelial cells at days 0, 3 and 6. qRT-PCR for Eya2 and Dmrt2 showed the highest and lowest fold change for them respectively, and immunohistochemistry showed that the former is being expressed at the three selected time points while the latter appears to be diminishing with very few cells expressing it until day 6.

SIGNIFICANCE

Results from this work is reporting the role of these TFs for the first time and will significantly contribute to the current understanding of the development and branching morphogenesis of the neonatal VP gland during the first week of postnatal development.

Expression of histone deacetylases 1, 2 and 3 in urothelial bladder cancer

BACKGROUND

Histone deacetylases (HDACs) are known to be associated with an overexpression in different types of cancer such as colon and prostate cancer. In this study we aimed to evaluate the protein expression of class I HDACs in urothelial carcinoma of the bladder.

METHODS

A tissue microarray containing 348 tissuesamples from 174 patients with a primary urothelial carcinoma of the bladder was immunohistochemically stained for HDAC 1, 2 and 3. Intensity of staining was evaluated and the association with clinico-pathological features and prognosis was assessed.

RESULTS

High HDAC expression levels were found in 40 to 60% of all investigated urothelial carcinomas (HDAC-1: 40%, HDAC-2: 42%, HDAC-3: 59%).HDAC-1 and HDAC-2 were significantly associated with higher tumour grades.Although all three markers could not predict progression in univariate analyses, high HDAC-1 expression was associated with a trend toward poorer prognosis. Patients with high-grade tumours and high expression levels of HDAC-1 were more likely to progress compared to all other patients (p < 0.05).

CONCLUSIONS

High-grade noninvasive papillary bladder tumours are associated with high expression levels of HDAC-1 and HDAC-2. High grade tumours in combination with high expression of HDAC-1 showed a worse prognosis than the other tumours. The high expression levels of HDACs observed particularly in high grade urothelial bladder cancer clearly warrant subsequent studies on the potential use of HDAC inhibitors as a novel therapeutic approach.

Nanoparticle delivery of mycophenolic acid upregulates PD-L1 on dendritic cells to prolong murine allograft survival

Conventional immunosuppressive drug delivery requires high systemic drug levels to provide therapeutic benefit, but frequently results in toxic side effects. Novel drug delivery methods, such as FDA-approved poly(lactic-co-glycolic acid) (PLGA) nanoparticles (NPs), are promising drug delivery platforms to reduce drug doses and minimize toxicity. Using murine models of skin transplantation, we investigated whether PLGA NPs would effectively deliver mycophenolic acid (MPA), a common clinical immunosuppressant, and avoid the toxicity of conventional drug delivery. We found that intermittent treatment with NPs encapsulated with MPA (NP-MPA) resulted in a significant extension of allograft survival than intermittent conventional MPA treatment even though the concentration of MPA within NP-MPA was a 1000-fold lower than conventional drug. Importantly, recipients who were administered NP-MPA intermittently avoided drug toxicity, whereas those treated with daily conventional drug manifested cytopenias. Dendritic cells (DCs) endocytosed NP-MPA to upregulate programmed death ligand-1 (PD-L1) and displayed a decreased ability to prime alloreactive T cells. Importantly, the ability of NP-MPA to promote allograft survival was partly PD-L1 dependent. Collectively, this study indicates that NPs are potent drug delivery tools that extend allograft survival without drug toxicity.

Anti-cancer effects of novel flavonoid vicenin-2 as a single agent and in synergistic combination with docetaxel in prostate cancer

The present study was conducted to determine the efficacy of novel flavonoid vicenin-2 (VCN-2), an active constituent of the medicinal herb Ocimum Sanctum Linn or Tulsi, as a single agent and in combination with docetaxel (DTL) in carcinoma of prostate (CaP). VCN-2 effectively induced anti-proliferative, anti-angiogenic and pro-apoptotic effect in CaP cells (PC-3, DU-145 and LNCaP) irrespective of their androgen responsiveness or p53 status. VCN-2 inhibited EGFR/Akt/mTOR/p70S6K pathway along with decreasing c-Myc, cyclin D1, cyclin B1, CDK4, PCNA and hTERT in vitro. VCN-2 reached a level of 2.6±0.3μmol/l in serum after oral administration in mice which reflected that VCN-2 is orally absorbed. The i.v. administration of docetaxel (DTL), current drug of choice in androgen-independent CaP, is associated with dose-limiting toxicities like febrile neutropenia which has lead to characterization of alternate routes of administration and potential combinatorial regimens. In this regard, VCN-2 in combination with DTL synergistically inhibited the growth of prostate tumors in vivo with a greater decrease in the levels of AR, pIGF1R, pAkt, PCNA, cyclin D1, Ki67, CD31, and increase in E-cadherin. VCN-2 has been investigated for radioprotection and anti-inflammatory properties. This is the first study on the anti-cancer effects of VCN-2. In conclusion, our investigations collectively provide strong evidence that VCN-2 is effective against CaP progression along with indicating that VCN-2 and DTL co-administration is more effective than either of the single agents in androgen-independent prostate cancer.

The significance of strong histone deacetylase 1 expression in the progression of prostate cancer

AIMS

Histone deacetylases (HDACs) play important roles in many types of cancer. Recently, it has been reported that HDAC1 expression in prostate cancer is significantly higher than in benign prostate cell lines and tissues. The expression of HDAC1 in association with the clinicopathological data was investigated to define its functional and pathological roles in prostate cancer.

METHODS AND RESULTS

HDAC1 expression was examined immunohistochemically in 148 patients with prostate cancer. Strong expression of HDAC1 in benign prostate glands, high-grade prostatic intraepithelial neoplasia (PIN) and prostate cancer was observed in 17/148 (11%), 19/71 (27%) and 69/148 (47%) patients. Strong HDAC1 expression was correlated with high Gleason score (P = 0.025) and high pT stage (P = 0.012). Patients with strong HDAC1 expression had higher biochemical recurrence rates (P = 0.0010). Furthermore, strong HDAC1 expression had a significant impact on patient biochemical recurrence rates in multivariate analysis (P = 0.004).

CONCLUSIONS

These results indicate that overexpression of HDAC1 contributes to progression and poor prognosis in prostate cancer. The findings may play an important role in the emergence of effective new approaches for therapy and prognostic markers of prostate cancer.

Cell-cycle regulators cdk2ap1 and bicalutamide suppress malignant biological interactions between prostate cancer and bone cells

INTRODUCTION

We examined whether the novel cell-cycle regulator cdk2-associated protein 1 (p12(cdk2ap1) or cdk2ap1), recently shown to regulate prostate cancer cell cycle and apoptosis, could have the capacity to reduce invasiveness and/or reduce malignant biological interactions between prostate cancer and bone cells. We also examined whether combining two cell-cycle arrest stimuli, cdk2ap1 plus bicalutamide (or casodex, CDX), could help enhance inhibition of prostate cancer cell phenotypes.

METHODS

We stably expressed cdk2ap1 in prostate cancer cell lines using lentiviral vectors, as well as several different co-culture assays to quantify cellular invasion, migration, and the effect of the treatments on interaction with the bone microenvironment.

RESULTS

We have determined that cdk2ap1 can further augment the effects of CDX on cell-cycle arrest, growth inhibition, and cellular invasion. Using a coculture model, we observed that either cdk2ap1 or cdk2ap1/CDX combination were able to reduce chemotaxis towards osteoblasts, and also reduce the osteoblastic proliferative response to prostate cancer. Also modified by cdk2ap1 and CDX were several signaling pathways associated with prostate cancer/bone crosstalk mechanisms involved in prostate cancer progression.

CONCLUSIONS

These results suggest that either cdk2ap1 or the cdk2ap1/CDX combination hold promise in regulating prostate cancer growth and malignant phenotypes, and potentially also in reducing procarcinogenic interactions with a bone microenvironment model, restoring malignant phenotypes and signaling to a more benign state.

Suberoylanilide hydroxamic acid (SAHA) induces growth arrest and apoptosis in pituitary adenoma cells

Pituitary adenomas, which account for 15-20% of intracranial tumors, are associated with significant morbidity and mortality, due in part, to hormone hypersecretion and mass effects following increased proliferation. Radiotherapy and surgery remain frontline treatment options; however, adverse side effects and surgical limitations to treat invasive tumors necessitate the need for novel therapeutic targets. This study tested the efficacy of the histone deacetylase inhibitor (HDACi), suberoylanilide hydroxamic acid (SAHA) in GH3, and MMQ pituitary adenoma cells. Clinically achievable concentrations of SAHA (500 nM-4 microM) induced growth arrest and increased cell death in GH3 pituitary adenoma cells. Further investigation into the mechanism of cell death revealed an increase in PARP cleavage and procaspase-3 activation, consistent with apoptotic cell death. SAHA also attenuated the expression of anti-apoptotic IAP (XIAP, survivin) and Bcl-2 family proteins (Bcl-2, Bcl-xL), but did not alter Bax expression. Together, these findings support a possible utility for SAHA alone or in combination with radiation for the treatment of pituitary adenoma.

Antiproliferative effects of AVN944, a novel inosine 5-monophosphate dehydrogenase inhibitor, in prostate cancer cells

Inosine 5-monophosphate dehydrogenase II, a key enzyme in the de novo synthesis of purine nucleotides, is expressed in prostate tumors and prostate cancer cells. AVN944 is a new, specific, noncompetitive IMPDH inhibitor. In this study, we investigated the effects of IMPDH inhibitor AVN944 on LNCaP, CWR22Rv1, DU145 and PC-3 human prostate cancer cells. AVN944 inhibited proliferation of these 4 prostate cancer cell lines and was associated with cell cycle G1 arrest of LNCaP cells and S-phase block of androgen-independent CWR22Rv1, DU145 and PC-3 cells. AVN944 induced caspase-dependentand caspase-independent cell death in LNCaP, CWR22Rv1, and DU145 cells. AVN944 induced expression of p53-target proteins Bok, Bax and Noxa in androgen-responsive cell lines and suppressed expression of survivin in prostate cancer cells regardless of their androgen sensitivity. AVN944 also induced differentiation of androgen-independent prostate cancer cells as indicated by morphological changes and increased expression of genes coding for prostasomal proteins, keratins and other proteins, including tumor suppressor genes MIG-6 and NDRG1. AVN944-differentiated androgen-independent DU145 and PC-3 cells are sensitized to TRAIL-induced apoptosis as demonstrated by induction of caspases and PARP cleavage. In summary, AVN944 inhibited the growth of human prostate cancer cells by inducing cell cycle arrest, cell death as well as differentiation. AVN944 is a novel, promising therapeutic agent that might be combined with other agents for treatment of human prostate cancer.

Perifosine induces differentiation and cell death in prostate cancer cells

We analyzed the mechanism of action for perifosine (D-21266), a new synthetic alkylphospholipid Akt inhibitor, using LNCaP and PC-3 prostate cancer cells. Perifosine treatment of PC-3 cells resulted in cytostatic and cytotoxic effects. Cytostatic effects were characterized by cell growth arrest, cell cycle block, and morphological changes, such as a cell enlargement and granulation, hallmarks of differentiating PC-3 cells. Specific differentiation markers including prostasomal, secretory and plasma membrane proteins, and keratins were induced by perifosine. Among them, we detected strong induction and secretion of CEACAM5 protein. In contrast, perifosine strongly reduced caveolin-1 RNA levels. Cytotoxic effects included para-apoptosis, apoptosis, and necrosis. To pursue the mechanisms responsible for these activities we focused on signaling pathways that lie downstream of Akt. Perifosine-triggered GSK-3beta activation in PC-3 and LNCaP cells resulted in the expression of GSK-3beta-related differentiation markers. This expression was reduced in the presence of specific siRNA for GSK-3beta or for its target CREB protein. The use of the GSK-3beta inhibitor lithium chloride indicated that GSK-3beta partially protects prostate cancer cells from the cytotoxic effects of perifosine. Together, these findings indicate that perifosine induces GSK-3beta-related differentiation and caspase-independent cell death in prostate cancer PC-3 cells. In addition our results identify specific biomarkers for perifosine therapy.

Functions of normal and malignant prostatic stem/progenitor cells in tissue regeneration and cancer progression and novel targeting therapies

This review summarizes the recent advancements that have improved our understanding of the functions of prostatic stem/progenitor cells in maintaining homeostasis of the prostate gland. We also describe the oncogenic events that may contribute to their malignant transformation into prostatic cancer stem/progenitor cells during cancer initiation and progression to metastatic disease stages. The molecular mechanisms that may contribute to the intrinsic or the acquisition of a resistant phenotype by the prostatic cancer stem/progenitor cells and their differentiated progenies with a luminal phenotype to the current therapies and disease relapse are also reviewed. The emphasis is on the critical functions of distinct tumorigenic signaling cascades induced through the epidermal growth factor system, hedgehog, Wnt/beta-catenin, and/or stromal cell-derived factor-1/CXC chemokine receptor-4 pathways as well as the deregulated apoptotic signaling elements and ATP-binding cassette multidrug transporter. Of particular therapeutic interest, we also discuss the potential beneficial effects associated with the targeting of these signaling elements to overcome the resistance to current treatments and prostate cancer recurrence. The combined targeted strategies toward distinct oncogenic signaling cascades in prostatic cancer stem/progenitor cells and their progenies as well as their local microenvironment, which could improve the efficacy of current clinical chemotherapeutic treatments against incurable, androgen-independent, and metastatic prostate cancers, are also described.

Histone deacetylases 1, 2 and 3 are highly expressed in prostate cancer and HDAC2 expression is associated with shorter PSA relapse time after radical prostatectomy

High activity of histone deacetylases (HDACs) causes epigenetic alterations associated with malignant cell behaviour. Consequently, HDAC inhibitors have entered late-phase clinical trials as new antineoplastic drugs. However, little is known about expression and function of specific HDAC isoforms in human tumours including prostate cancer. We investigated the expression of class I HDACs in 192 prostate carcinomas by immunohistochemistry and correlated our findings to clinicopathological parameters including follow-up data. Class I HDAC isoforms were strongly expressed in the majority of the cases (HDAC1: 69.8%, HDAC2: 74%, HDAC3: 94.8%). High rates of HDAC1 and HDAC2 expression were significantly associated with tumour dedifferentiation. Strong expression of all HDACs was accompanied by enhanced tumour cell proliferation. In addition, HDAC2 was an independent prognostic marker in our prostate cancer cohort. In conclusion, we showed that the known effects of HDACs on differentiation and proliferation of cancer cells observed in vitro can also be confirmed in vivo. The class I HDAC isoforms 1, 2 and 3 are differentially expressed in prostate cancer, which might be important for upcoming studies on HDAC inhibitors in this tumour entity. Also, the highly significant prognostic value of HDAC2 clearly deserves further study.

Dual inhibitors of inosine monophosphate dehydrogenase and histone deacetylases for cancer treatment

Mycophenolic acid (MPA), an inhibitor of IMP-dehydrogenase (IMPDH), is used worldwide in transplantation. Recently, numerous studies showed its importance in cancer treatment. Consequently, MPA entered clinical trials in advanced multiple myeloma patients. Suberoylanilide hydroxamic acid (SAHA), a potent differentiation agent acting through inhibition of histone deacetylases (HDACs), was recently approved for treatment of cutaneous T cell lymphoma. We report herein the synthesis of dual inhibitors of IMPDH and HDACs. We found that mycophenolic hydroxamic acid (9, MAHA) inhibits both IMPDH (Ki=30 nM) and HDAC (IC50=5.0 microM). A modification of SAHA with groups known to interact with IMPDH afforded a SAHA analogue 14, which inhibits IMPDH (Ki=1.7 microM) and HDAC (IC50=0.06 microM). Both MAHA (IC50=4.8 microM) and SAHA analogue 14 (IC50=7.7 microM) were more potent than parent compounds as antiproliferation agents. They were also significantly more potent as differentiation inducers.

Dynamics of the epithelium during canalization of the rat ventral prostate

Outgrowth and branching of solid cords are the initial events in postnatal prostatic morphogenesis. These processes involve cell proliferation and their projection into the stroma and precede epithelial canalization. The purpose of the present study was to examine the dynamics of the prostate epithelium during canalization of the rat ventral prostate in the first week of postnatal development using histological, stereological, and ultrastructural analyses. The terminal deoxynucleotidyltransferase [TdT]-mediated deoxy-UTP nick end labeling assay was used to investigate the occurrence of DNA fragmentation. Our results demonstrate that canalization of the prostate epithelium starts as early as on day 1 (24 hr after birth) and progresses thereafter. By the end of the first week (day 6), luminal volume density reached approximately 3% (P < 0.05) of the organ. Canalization was the result of epithelial cell differentiation and apoptosis. The former involved organization of the epithelial cells into a single layer sitting on the basement membrane, polarization, enlargement of secretory organelles and accumulation of secretory vesicles, microvilli formation, and establishment of the adult pattern of cell junctions. The latter was observed to occur mostly to epithelial cells not in contact with the basement membrane. Structures of variable electron density were observed in the developing lumen. In conclusion, different phenomena seem to be involved in the canalization of the rat ventral prostate. However, it was evident from the present results that complex epithelial cell fate decisions take place during this process.

Molecular markers in the diagnosis of prostate cancer

The genetic alterations leading to prostate cancer are gradually being discovered. A wide variety of genes have been associated with prostate cancer development as well as tumor progression. Knowledge of gene polymorphisms associated with disease aid in the understanding of important pathways involved in this process and may result in the near future in clinical applications. Urinary molecular markers will soon be available to aid in the decision of repeat prostate biopsies. Recent findings suggest the importance of androgen signaling in disease development and progression. The further understanding of interaction of inflammation, diet, and genetic predisposition will improve risk stratification in the near future.