Regulatory T cells in the bone marrow microenvironment in patients with prostate cancer

Human prostate cancer frequently metastasizes to bone marrow. What defines the cellular and molecular predilection for prostate cancer to metastasize to bone marrow is not well understood. CD4⁺CD25⁺ regulatory T (Treg) cells contribute to self-tolerance and tumor immune pathology. We now show that functional Treg cells are increased in the bone marrow microenvironment in prostate cancer patients with bone metastasis, and that CXCR4/CXCL12 signaling pathway contributes to Treg cell bone marrow trafficking. Treg cells exhibit active cell cycling in the bone marrow, and bone marrow dendritic cells express high levels of receptor activator of NFκB (RANK), and promote Treg cell expansion through RANK and its ligand (RANKL) signals. Furthermore, Treg cells suppress osteoclast differentiation induced by activated T cells and M-CSF, adoptive transferred Treg cells migrate to bone marrow, and increase bone mineral intensity in the xenograft mouse models with human prostate cancer bone marrow inoculation. In vivo Treg cell depletion results in reduced bone density in tumor bearing mice. The data indicates that bone marrow Treg cells may form an immunosuppressive niche to facilitate cancer bone metastasis and contribute to bone deposition, the major bone pathology in prostate cancer patients with bone metastasis. These findings mechanistically explain why Treg cells accumulate in the bone marrow, and demonstrate a previously unappreciated role for Treg cells in patients with prostate cancer. Thus, targeting Treg cells may not only improve anti-tumor immunity, but also ameliorate bone pathology in prostate cancer patients with bone metastasis.

Correction to: Androgen receptor regulates expression of skeletal muscle-specific proteins and muscle cell types

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Correction: Synthesis, structural characterization, electrochemical behavior and anticancer activity of gold(iii) complexes of meso-1,2-di(1-naphthyl)-1,2-diaminoethane and tetraphenylporphyrin

Correction for ‘Synthesis, structural characterization, electrochemical behavior and anticancer activity of gold(iii) complexes of meso-1,2-di(1-naphthyl)-1,2-diaminoethane and tetraphenylporphyrin’ by Muhammad Altaf et al., New J. Chem., 2016, 40, 8288–8295, DOI: 10.1039/C6NJ00692B.

Correction: Synthesis, spectroscopic characterization, X-ray structure and electrochemistry of new bis(1,2-diaminocyclohexane)gold(iii) chloride compounds and their anticancer activities against PC3 and SGC7901 cancer cell lines

Correction for ‘Synthesis, spectroscopic characterization, X-ray structure and electrochemistry of new bis(1,2-diaminocyclohexane)gold(iii) chloride compounds and their anticancer activities against PC3 and SGC7901 cancer cell lines’ by Said S. Al-Jaroudi et al., New J. Chem., 2014, 38, 3199–3211, DOI: 10.1039/C3NJ01624B.

Polymorphism rs547984 on human chromosome 1q43 is not associated with primary open angle glaucoma in a Saudi cohort

Background

To investigate the association between polymorphism rs547984, located in close proximity to the Zona Pellucida Glycoprotein 4 (ZP4) gene on human chromosome 1q43 and primary open angle glaucoma (POAG).

Method

Polymorphism rs547984 was genotyped using Taq-Man® assay in 185 subjects comprising of 90 unrelated POAG cases and 95 controls of Saudi origin.

Results

Association analysis between cases and controls revealed no significant genotype distribution under additive (p = 0.356), dominant (p = 0.517) and recessive (p = 0.309) models. Besides, the allele frequency distribution was also found to be non-significant (p = 0.70). The minor “A” allele frequency was found to be 0.49 and 0.50 among POAG cases and controls, respectively. In addition, specific clinical indices used to assess severity of glaucoma such as intraocular pressure (IOP), cup/disc ratio and number of anti-glaucoma medication also did not show any significant genotype distribution in POAG cases.

Conclusion

Polymorphism rs547984 is neither associated with any clinical indices important for POAG such as IOP and cup/disc ratio nor is a risk factor for POAG in the Saudi cohort.

Lack of association between polymorphism rs540782 and primary open angle glaucoma in Saudi patients

Background

To investigate whether polymorphism rs540782 on chromsome 1, in close proximity to the Zona Pellucida Glycoprotein 4 (ZP4) gene, is a risk factor for primary open angle glaucoma (POAG).

Method

The study genotyped 92 unrelated POAG cases and 95 control subjects from Saudi Arabia using Taq-Man® assay.

Results

The genotype frequency distribution did not deviate significantly from the Hardy-Weinberg equilibrium (p > 0.05). Overall, both the genotype and allele frequencies were not significantly different between cases and controls. The minor ‘C’ allele frequency was 49.4%, which was comparable to the Japanese population and higher than the Indian and Afro-Caribbean populations. Similarly, no significant association was found between genotypes and systemic diseases and health awareness/behavior domain variables. Importantly, glaucoma specific indices, such as intraocular pressure, cup/disc ratio and number of anti-glaucoma medication, also showed no statistically significant effect of genotypes within POAG cases.

Conclusion

Polymorphism rs540782 is not a risk factor for POAG in the Saudi cohort.

Polymorphism rs7555523 in transmembrane and coiled-coil domain 1 (TMCO1) is not a risk factor for primary open angle glaucoma in a Saudi cohort

Background

We investigated whether polymorphism rs7555523 (A > C) in human transmembrane and coiled-coil domain 1 (TMCO1) gene is a risk factor for primary open angle glaucoma (POAG) in a Saudi cohort.

Methods

A cohort of 87 unrelated POAG cases and 94 control subjects from Saudi Arabia were genotyped using Taq-Man® assay. The association of genotypes with POAG and other glaucoma specific clinical indices was investigated.

Results

The genotype and allele frequency of polymorphism rs7555523 at TMCO1 did not show any statistically significant association with POAG as compared to controls. The minor allele frequency was 0.103 in cases and 0.085 in controls. Except for awareness of glaucoma (p = 0.036), no significant association of genotypes were seen with glaucoma specific clinical indices such as intraocular pressure (IOP), cup/disc ratio and number of anti-glaucoma medications used. Binary logistic regression analysis (adjusted for age and gender) showed that age was a significant indicator for the development of glaucoma in this group (adjusted odds ratio = 1.2; 95 % confidence interval = 1.078–1.157; p < 0.001).

Conclusion

Our study was unable to replicate the findings of previously reported association for polymorphism rs7555523 in TMCO1 with POAG and related clinical indices such as IOP and cup/disc ratio indicating that this variant is not a risk factor for POAG in the Saudi cohort.

Analysis of Polymorphism rs1900004 in Atonal bHLH Transcription Factor 7 in Saudi Patients with Primary Open Angle Glaucoma

AIMS

To investigate the association between the rs1900004 polymorphism in the atonal bHLH transcription factor 7 (ATOH7) gene and primary open angle glaucoma (POAG) in Saudi patients.

METHODS

Eighty-seven unrelated POAG cases and 94 unrelated control subjects of Saudi origin were genotyped utilizing a TaqMan^® assay. The association between mutant genotypes and POAG and its related clinical indices was investigated.

RESULTS

The genotype and allele frequencies of the polymorphism in ATOH7 did not show any statistically significant association with POAG compared to controls. The minor allele frequency was 0.32 in both cases and controls. None of the demographic, systemic diseases nor glaucoma-specific clinical indices such as intraocular pressure (IOP), cup/disc ratio, and number of antiglaucoma medication, showed any significant association with genotypes. Binary logistic regression analysis (adjusted for age and gender) showed that age was a marginally significant risk factor for the development of glaucoma (adjusted odds ratio = 1.1; 95% confidence interval = 1.079-1.158; p < 0.0001).

CONCLUSIONS

The study did not detect any direct link between genotype/allele frequency of rs1900004 in ATOH7 and POAG or its related clinical indices such as IOP and cup/disc ratio indicating that this polymorphism is not a risk factor for POAG in a Saudi cohort.

Generation of human iPS cell line SKiPSc1 from healthy Human Neonatal Foreskin Fibroblast cells

The SKiPSc1 induced pluripotent stem (iPS) cell line was generated from Human Neonatal Foreskin Fibroblasts (HNFFs) obtained from a healthy donor infant that were reprogrammed using non-integrating Sendai viral vectors expressing Oct3/4, Sox2, c-Myc, and Klf4.

Analysis of Cyclin-Dependent Kinase Inhibitor-2B rs1063192 Polymorphism in Saudi Patients with Primary Open-Angle Glaucoma

AIMS

To investigate whether the polymorphism rs1063192 (A>G) in the cyclin-dependent kinase Inhibitor-2B (CDKN2B) gene is a risk factor for primary open-angle glaucoma (POAG).

METHOD

A case-control study was conducted wherein we genotyped 87 unrelated POAG cases and 94 control subjects from Saudi Arabia using the Taq-Man^® assay.

RESULTS

The minor allele frequency was 0.20 in POAG cases and 0.21 in controls. Both the genotype and allele frequencies were not significantly different between cases and controls. No significant association was found between genotypes and glaucoma clinical indices, except that the mutant homozygous genotype (G/G) was associated with the family history of glaucoma (p = 0.024).

CONCLUSION

Polymorphism rs1063192 in CDKN2B is not a risk factor for POAG in Saudi cohort.

Synthesis, structural characterization, electrochemical behavior and anticancer activity of gold(iii) complexes of meso-1,2-di(1-naphthyl)-1,2-diaminoethane and tetraphenylporphyrin

Gold(iii) complexes were tested for in vitro antiproliferative activity against three human tumor cell lines. All complexes exhibited remarkable cytotoxicity.

The synthesis, spectroscopic characterization and anticancer activity of new mono and binuclear phosphanegold(i) dithiocarbamate complexes

Four new gold(i) complexes were synthesized and characterized. The structure of [t-Bu₃PAuS₂CN(C₇H₇)₂] was determined by X-ray diffraction.

Synthesis, spectroscopic characterization, electrochemical behavior and computational analysis of mixed diamine ligand gold(III) complexes: antiproliferative and in vitro cytotoxic evaluations against human cancer cell lines

The gold(III) complexes of the type [(DACH)Au(en)]Cl3, 1,2-Diaminocyclohexane ethylenediamine gold(III) chloride [where 1,2-DACH = cis-, trans-1,2- and S,S-1,2diaminocyclohexane and en = ethylenediamine] have been synthesized and characterized using various analytical and spectroscopic techniques including elemental analysis, UV-Vis and FTIR spectra; and solution as well as solid-state NMR measurements. The solid-state (13)C NMR shows that 1,2-diaminocyclohexane (1,2-DACH) and ethylenediamine (en) are strongly bound to the gold(III) center via N donor atoms. The stability of the mixed diamine ligand gold(III) was determined by (1)H and (13)C NMR spectra. Their electrochemical behavior was studied by cyclic voltammetry. The structural details and relative stabilities of the four possible isomers of the complexes were also reported at the B3LYP/LANL2DZ level of theory. The coordination sphere of these complexes around gold(III) center adopts distorted square planar geometry. The computational study also demonstrates that trans- conformations is slightly more stable than the cis-conformations. The antiproliferative effects and cytotoxic properties of the mixed diamine ligand gold(III) complexes were evaluated in vitro on human gastric SGC7901 and prostate PC3 cancer cells using MTT assay. The antiproliferative study of the gold(III) complexes on PC3 and SGC7901 cells indicate that complex 1 is the most effective antiproliferative agent among mixed ligand based gold(III) complexes 1-3. The IC50 data reveal that the in vitro cytotoxicity of complexes 1 and 3 against SGC7901 cancer cells are fairly better than that of cisplatin.

In vivo surface dose measurement using GafChromic film dosimetry in breast cancer radiotherapy: comparison of 7-field IMRT, tangential IMRT and tangential 3D-CRT

Purpose

The purpose of this study was to compare the surface dose of 7-field IMRT (7 F-IMRT), tangential beam IMRT (TB-IMRT), and tangential beam 3D-CRT (3D-CRT) of breast cancer patients receiving adjuvant radiotherapy by means of in vivo GafChromic film dosimetry.

Material and methods

Breast cancer patients receiving adjuvant radiotherapy of the whole breast or the chest wall were eligible for the study. Study patients were treated with a treatment plan using two different radiotherapy techniques (first patient series, 3D-CRT followed by TB-IMRT; second patient series, TB-IMRT followed by 7 F-IMRT). The surface dose was evaluated on three consecutive treatment fractions per radiotherapy technique using in vivo GafChromic film dosimetry. The paired t-test was used to assess the difference of in vivo GafChromic film readings or calculated plan parameters of the compared pairs of radiation techniques for statistical significance.

Results

Forty-five unselected breast cancer patients were analysed in this study. 7 F-IMRT significantly reduced the surface dose compared to TB-IMRT. Differences were greatest in the central and lateral breast or chest wall region and amounted to a dose reduction of -11.8% to -18.8%. No significant difference of the surface dose was observed between TB-IMRT and 3D-CRT. A corresponding observation was obtained for the calculated skin dose derived from dose-volume histograms.

Conclusions

In adjuvant breast cancer radiotherapy, 7 F-IMRT offers a significantly reduced surface dose compared to TB-IMRT or 3D-CRT.

Identification of breast cancer patients with a high risk of developing brain metastases: a single-institutional retrospective analysis

Background

The objective of this study was to identify breast cancer patients with a high risk of developing brain metastases who may benefit from pre-emptive medical intervention.

Methods

Medical records of 352 breast cancer patients with local or locoregional disease at diagnosis were retrospectively analysed. The brain metastasis-free survival was estimated using the Kaplan-Meier method and patient groups were compared using the log rank test. The simultaneous relationship of multiple prognostic factors was assessed using Cox’s proportional hazard regression analysis. The Fisher exact test was used to test the difference of proportions for statistical significance.

Results

On univariate analysis, statistically highly significant unfavourable risk factors for the brain metastasis-free survival were negative ER status, negative PR status, and triple negative tumor subtype. Young age at diagnosis (≤35 years) and advanced disease stage were not statistically significant (p = 0.10). On multivariate analysis, the only independent significant factor was the ER status (negative ER status; hazard radio (95% confidence interval), 5.1 (1.8-14.6); p = 0.003). In the subgroup of 168 patients with a minimum follow-up of 24 months, 49 patients developed extracranial metastases as first metastatic event. Of those, 7 of 15 (46.6%) with a negative ER status developed brain metastases compared to 5 of 34 (14.7%) with a positive ER status (Fisher exact test, p = 0.03). The median time interval (minimum-maximum) between the diagnosis of extracranial and brain metastases was 7.5 months (1-30 months).

Conclusions

Breast cancer patients with extracranial metastasis and negative ER status exhibited an almost 50% risk of developing brain metastasis during their course of disease. Future studies are highly desired to evaluate the efficacy of pre-emptive medical intervention such as prophylactic treatment or diagnostic screening for high risk breast cancer patients.

Synthesis, spectroscopic characterization, X-ray structure and electrochemistry of new bis(1,2-diaminocyclohexane)gold(iii) chloride compounds and their anticancer activities against PC3 and SGC7901 cancer cell lines

Promising cytotoxic gold(iii) complexes with general formula [Au{(1,2-DACH)}₂]Cl₃ are reported.

Some new [(thione)2Au(diamine)]Cl3 complexes: synthesis, spectroscopic characterization, computational and in vitro cytotoxic studies

Recent advances in oncology are focused on developing new complexes of gold(III) with various ligands that show augmented anti-proliferative potential and reduced toxicity as compared to cis-platin. In this study, new Au(III) complexes of the type [(thione)2Au(diamine)]Cl3 are reported, where thione=1,3-imidazolidine-2-thione (Imt), 1,3-Diazinane-2-thione (Diaz) and diamine=1,2-diaminoethane (en), 1,3-diaminopropane (pn) or 1,4-diaminobutane (bn). The solid state IR as well as (13)C and (15)N NMR data indicate that Au(III) center is bonded via sulfur of thiocarbonyl SC site of the thiones and also chelated by the diamines from the trans side of coordinated thiones. Spectroscopic data are evaluated by comparisons with calculated data from the built and optimized structure by GAUSSIAN 09 at the RB3LYP level with LanL2DZ bases set. These new Au(III) complexes based on mixed thione and diamine ligands are very similar to the square planar structure of tetracoordinate [Au(en)2]Cl3complex. In this study, cytotoxicity data for these gold(III) complexes against C6 glioma cell lines are also reported, and the results indicate some complexes have cytotoxicity comparable to cis-platin.

Intensity modulated radiotherapy of upper abdominal malignancies: dosimetric comparison with 3D conformal radiotherapy and acute toxicity

Background

The goal of this study was to assess a possible dosimetric advantage of intensity modulated radiotherapy (IMRT) of upper abdominal malignancies compared to three-dimensional conformal radiotherapy (3DCRT), and to assess the impact of IMRT on acute toxicity.

Methods

Thirty-one unselected consecutive patients with upper abdominal malignancies were treated with definitive (n =16) or postoperative (n =15) IMRT. Twenty-one patients (67.7%) received concomitant chemotherapy. 3DCRT plans were generated for comparison, and analysis of variance (ANOVA) for repeated measurements was used to test for significant difference of dosimetric parameters. Acute toxicity was assessed weekly using the Common Terminology Criteria for Adverse Events (CTCAE) grading scale.

Results

IMRT plans showed a small but statistically significant improvement of the conformity index compared to 3DCRT plans (difference (95% confidence interval), -0.06 (−0.109 to-0.005); p = 0.03). The homogeneity index was not significantly improved (p = 0.10). A significantly reduced high dose volume on cost of a significantly increased low dose volume was observed for the kidneys. The acute toxicity appeared to be less than commonly reported for corresponding patients treated with 3DCRT. No patient developed grade 3 or 4 non-hematological acute toxicity, and the most common grade 2 toxicity was vomiting (9.7%).

Conclusions

IMRT offers the potential of a clinically relevant dosimetric advantage compared to 3DCRT in terms of a reduced acute toxicity. Further optimization of the radiotherapy technique and more clinical trials are required before IMRT is routinely used for upper abdominal malignancies.

Targeting thymic epithelia AR enhances T-cell reconstitution and bone marrow transplant grafting efficacy

Although thymic involution has been linked to the increased testosterone in males after puberty, its detailed mechanism and clinical application related to T-cell reconstitution in bone marrow transplantation (BMT) remain unclear. By performing studies with reciprocal BMT and cell-specific androgen receptor (AR) knockout mice, we found that AR in thymic epithelial cells, but not thymocytes or fibroblasts, played a more critical role to determine thymic cellularity. Further dissecting the mechanism using cell-specific thymic epithelial cell-AR knockout mice bearing T-cell receptor transgene revealed that elevating thymocyte survival was due to the enhancement of positive selection resulting in increased positively selected T-cells in both male and female mice. Targeting AR, instead of androgens, either via genetic knockout of thymic epithelial AR or using an AR-degradation enhancer (ASC-J9®), led to increased BMT grafting efficacy, which may provide a new therapeutic approach to boost T-cell reconstitution in the future.

Androgen receptor influences on body defense system via modulation of innate and adaptive immune systems: lessons from conditional AR knockout mice

Upon insult, such as infection or tissue injury, the innate and adaptive immune systems initiate a series of responses to defend the body. Recent studies from immune cell-specific androgen receptor (AR) knockout mice demonstrated that androgen and its receptor (androgen/AR) play significant roles in both immune regulations. In the innate immunity, androgen/AR is required for generation and proper function of neutrophils; androgen/AR also regulates wound healing processes through macrophage recruitment and proinflammatory cytokine production. In adaptive immunity, androgen/AR exerts suppressive effects on development and activation of T and B cells. Removal of such suppression causes thymic enlargement and excessive export of immature B cells. Altogether, androgen/AR plays distinct roles in individual immune cells, and targeting androgen/AR may help in treatment and management of immune-related diseases.

Impact of health education on community knowledge, attitudes and behaviour towards solid waste management in Al Ghobeiry, Beirut

The risks posed by accumulation of solid waste are most obvious in developing countries, where waste collection and treatment is often inadequate. This study aimed to determine the impact of a health education intervention (based on lectures and focus group discussions) on community knowledge, attitudes and behaviours concerning solid waste management in Al Ghobeiry, Beirut. A randomly selected sample of 320 inhabitants were divide into intervention and control groups who completed the same questionnaire in the pre- and post-intervention phases. Compared with the control group the intervention group, who attended the health education sessions, showed: significantly better knowledge about the problems of and diseases spread by accumulation of solid waste; better attitudes to management of solid waste collection; and improved practices in terms of handling and recycling of household waste. There was an observed increased participation by people in cleaning campaigns and voluntary work in all the municipality activities.

[Knowledge, attitudes and practices among religious students concerning family planning]

To determine the knowledge, attitude and practices concerning family planning of students attending religious schools in Lebanon, we conducted a cross-sectional study of 450 male and female students. A validated structured questionnaire was completed by the students. The majority of the students (65%) had a moderate level of knowledge, males more than females, but females had more positive beliefs and attitudes. More females agreed with family planning programmes and methods than males, but 35% had a negative attitude to family planning; a significant percentage had negative attitudes to contraceptive methods based on their view that they are not allowed (haram) in Islam. Among the married students, less than 40% used a family planning method; of those, the majority used a female method. Religion plays an important role in the health behaviour of religious students. Religious leaders can therefore inhibit or promote family planning, which will affect the success of family planning programmes. Thus, they should be included in the development and promotion of family planning programmes.

Age of 40 years or younger is an independent risk factor for locoregional failure in early breast cancer: a single-institutional analysis in saudi arabia

Background. This study was undertaken to evaluate the impact of prognostic factors on the locoregional failure-free survival of early breast cancer patients. Methods. In this single-institutional study, 213 breast cancer patients were retrospectively analysed. Fifty-five of 213 patients were ≤40 years of age at diagnosis. The impact of patient- or treatment-related factors on the locoregional failure-free survival was assessed using the Kaplan-Meier method. The simultaneous impact of factors on the locoregional failure-free survival was assessed using the Cox proportional hazards regression analysis. Results. The median follow-up time of the censored patients was 22 months (mean 28 months, range 3-92 months). On univariate analysis, statistically significant factors for the locoregional failure-free survival were the age (≤40 versus >40 years), T stage (Tis, T0-2 versus T3-4), molecular tumor type (luminal A versus luminal B, Her2neu overexpression, or triple negative), and lymphovascular status (LV0 versus LV1). On multivariate analysis, age and T stage remained statistically significant. Conclusions. Being 40 years or younger has a statistically significant independent adverse impact on the locoregional failure-free survival of patients with early breast cancer.

Epidemiology of breast cancer patients at a tertiary care center in the Eastern Province of Saudi Arabia

BACKGROUND

Breast cancer is the most common cancer in Saudi Arabia. However, detailed published epidemiologic data are scarce. In this study, breast cancer patients at a tertiary care hospital were characterized and compared with data from the United States.

METHODS

Medical records were retrospectively reviewed of female patients with confirmed diagnosis of invasive breast cancer who consulted with Saad Specialist Hospital between 2004 and 2011. Descriptive statistics were calculated and compared with published data.

RESULTS

Two-hundred and sixty-two female patients with cytologically or histologically confirmed diagnosis of invasive breast cancer were identified and analyzed. Compared to published American data derived from the SEER database, patients were diagnosed at a markedly younger age (<50 years: 57.5% versus 12.5%) and more advanced disease (localized disease: 28.6% versus 61.2%). The difference of the age at diagnosis could not be fully explained by the different age structures of the Saudi Arabian and American population in our analysis. Although the overall mastectomy rate was higher (58.2% versus 38.5%), no relevant difference in the mastectomy rates was found if analyzed by stage.

CONCLUSION

Our data suggest that breast cancer in this part of Saudi Arabia is diagnosed at a much higher stage compared to the United States. More effort in awareness campaigns, easier access to screening and treatment are needed to improve the prognosis and to reduce the currently relatively high mastectomy rate.

Synthesis, characterization and anti proliferative effect of [Au(en)2]Cl3 and [Au(N-propyl-en)2]Cl3 on human cancer cell lines

Two Au(III) complexes of the type [Au(en)2]Cl3 (2a) and [Au(N-pr-en)2]Cl3 (3a) were synthesized by reacting Auric acid (HAuCl(4)·3H2O) with 2 equiv. ethylenediamine (en) or N-alkyl substituted ethylenediamine ligands. This metallodrug was characterized by various analytical and spectroscopic techniques such as elemental analysis, UV-Vis, Far-IR, 1H NMR and solution 13C as well as solid 13C and 15N NMR. Potentiality of [Au(en)2]Cl3 and [Au(N-pr-en)2]Cl3 as an anti-cancer agent were investigated by measuring some relevant physicochemical and biochemical properties such as stability of Au-N bonds by vibrational stretching from Far IR as well as cytotoxicity and stomach cancer cell inhibiting effect, respectively. The solid-state 15N NMR chemical shift shows that the ligand is strongly bound to gold(III) centre via N atoms. The computational study of 2a shows that the gold coordination sphere adopts distorted square planar geometry with bidentate ethylenediamine ligands acting as a tetradentate chelate. While stable in the solution state, the in vitro biological studies performed with these compounds 2a in solution showed higher activity towards the inhibitory effects of the human cancer cell lines such as prostate cancer (PC-3) and gastric carcinoma (SGC-7901) than that of the N-substituted gold(III) complex (3a). Cytotoxicity of the new compounds has also been estimated in PC-3 and SGC-7901 cells.

Impact of the frequency of online verifications on the patient set-up accuracy and set-up margins

Purpose

The purpose of the study was to evaluate the patient set-up error of different anatomical sites, to estimate the effect of different frequencies of online verifications on the patient set-up accuracy, and to calculate margins to accommodate for the patient set-up error (ICRU set-up margin, SM).

Methods and materials

Alignment data of 148 patients treated with inversed planned intensity modulated radiotherapy (IMRT) or three-dimensional conformal radiotherapy (3D-CRT) of the head and neck (n = 31), chest (n = 72), abdomen (n = 15), and pelvis (n = 30) were evaluated. The patient set-up accuracy was assessed using orthogonal megavoltage electronic portal images of 2328 fractions of 173 planning target volumes (PTV). In 25 patients, two PTVs were analyzed where the PTVs were located in different anatomical sites and treated in two different radiotherapy courses. The patient set-up error and the corresponding SM were retrospectively determined assuming no online verification, online verification once a week and online verification every other day.

Results

The SM could be effectively reduced with increasing frequency of online verifications. However, a significant frequency of relevant set-up errors remained even after online verification every other day. For example, residual set-up errors larger than 5 mm were observed on average in 18% to 27% of all fractions of patients treated in the chest, abdomen and pelvis, and in 10% of fractions of patients treated in the head and neck after online verification every other day.

Conclusion

In patients where high set-up accuracy is desired, daily online verification is highly recommended.

Tangential beam IMRT versus tangential beam 3D-CRT of the chest wall in postmastectomy breast cancer patients: a dosimetric comparison

Background

This study evaluates the dose distribution of reversed planned tangential beam intensity modulated radiotherapy (IMRT) compared to standard wedged tangential beam three-dimensionally planned conformal radiotherapy (3D-CRT) of the chest wall in unselected postmastectomy breast cancer patients

Methods

For 20 unselected subsequent postmastectomy breast cancer patients tangential beam IMRT and tangential beam 3D-CRT plans were generated for the radiotherapy of the chest wall. The prescribed dose was 50 Gy in 25 fractions. Dose-volume histograms were evaluated for the PTV and organs at risk. Parameters of the dose distribution were compared using the Wilcoxon matched pairs test.

Results

Tangential beam IMRT statistically significantly reduced the ipsilateral mean lung dose by an average of 21% (1129 cGy versus 1437 cGy). In all patients treated on the left side, the heart volume encompassed by the 70% isodose line (V70%; 35 Gy) was reduced by an average of 43% (5.7% versus 10.6%), and the mean heart dose by an average of 20% (704 cGy versus 877 cGy). The PTV showed a significantly better conformity index with IMRT; the homogeneity index was not significantly different.

Conclusions

Tangential beam IMRT significantly reduced the dose-volume of the ipsilateral lung and heart in unselected postmastectomy breast cancer patients.

NF-kappaB regulates androgen receptor expression and prostate cancer growth

Prostate cancers that progress during androgen-deprivation therapy often overexpress the androgen receptor (AR) and depend on AR signaling for growth. In most cases, increased AR expression occurs without gene amplification and may be due to altered transcriptional regulation. The transcription factor nuclear factor (NF)-kappaB, which is implicated in tumorigenesis, functions as an important downstream substrate of mitogen-activated protein kinase, phosphatidylinositol 3-kinase, AKT, and protein kinase C and plays a role in other cancer-associated signaling pathways. NF-kappaB is an important determinant of prostate cancer clinical biology, and therefore we investigated its role in the regulation of AR expression. We found that NF-kappaB expression in prostate cancer cells significantly increased AR mRNA and protein levels, AR transactivation activity, serum prostate-specific antigen levels, and cell proliferation. NF-kappaB inhibitors decrease AR expression levels, prostate-specific antigen secretion, and proliferation of prostate cancer cells in vitro. Furthermore, inhibitors of NF-kappaB demonstrated anti-tumor activity in androgen deprivation-resistant prostate cancer xenografts. In addition, levels of both NF-kappaB and AR were strongly correlated in human prostate cancer. Our data suggest that NF-kappaB can regulate AR expression in prostate cancer and that NF-kappaB inhibitors may have therapeutic potential.

Neutropenia with impaired host defense against microbial infection in mice lacking androgen receptor

Neutrophils, the major phagocytes that form the first line of cell-mediated defense against microbial infection, are produced in the bone marrow and released into the circulation in response to granulocyte-colony stimulating factor (G-CSF). Here, we report that androgen receptor knockout (ARKO) mice are neutropenic and susceptible to acute bacterial infection, whereas castration only results in moderate neutrophil reduction in mice and humans. Androgen supplement can restore neutrophil counts via stabilizing AR in castrated mice, but not in ARKO and testicular feminization mutant (Tfm) mice. Our results show that deletion of the AR gene does not influence myeloid lineage commitment, but significantly reduces the proliferative activity of neutrophil precursors and retards neutrophil maturation. CXCR2-dependent migration is also decreased in ARKO neutrophils as compared with wild-type controls. G-CSF is unable to delay apoptosis in ARKO neutrophils, and ARKO mice show a poor granulopoietic response to exogenous G-CSF injection. In addition, AR can restore G-CSF–dependent granulocytic differentiation upon transduction into ARKO progenitors. We further found that AR augments G-CSF signaling by activating extracellular signal-regulated kinase 1/2 and also by sustaining Stat3 activity via diminishing the inhibitory binding of PIAS3 to Stat3. Collectively, our findings demonstrate an essential role for AR in granulopoiesis and host defense against microbial infection.

Susceptibility to autoimmunity and B cell resistance to apoptosis in mice lacking androgen receptor in B cells

Estrogens have been linked to a higher female incidence of autoimmune diseases. The role of androgen and the androgen receptor (AR) in autoimmune diseases, however, remains unclear. Here we report that the lack of AR in B cells in different strains of mice, namely general AR knockout, B cell-specific AR knockout, and naturally occurring testicular feminization mutation AR-mutant mice, as well as castrated wild-type mice, results in increased B cells in blood and bone marrow. Analysis of the targeted mice, together with bone marrow transplantation using Rag1(-/-) recipients, overexpression of retrovirally encoded AR-cDNA, and small interfering RNA-mediated AR mRNA knockdown approaches also show that the B cell expansion results from resistance to apoptosis and increased proliferation of bone marrow precursor B cells, accompanied by changes in several key modulators related to apoptosis, such as Fas/FasL signals, caspases-3/-8, nuclear factor-kappaB, and Bcl-2. We also show that the effects of AR loss are, in part, B cell intrinsic. Mice bearing AR-deficient B cells show increased levels of serum IgG2a and IgG3 as well as basal double-stranded DNA-IgG antibodies and are more vulnerable to development of collagen-induced arthritis. Together, these data indicate that androgen/AR play a crucial role in B cell homeostasis and tolerance. Therapies targeting AR might provide an alternative strategy with which to battle autoimmune diseases.

Tissue prostate-specific antigen facilitates refractory prostate tumor progression via enhancing ARA70-regulated androgen receptor transactivation

Despite being well recognized as the best biomarker for prostate cancer, pathophysiologic roles of prostate-specific antigen (PSA) remain unclear. We report here that tissue PSA may be involved in the hormone-refractory prostate cancer progression. Histologic analyses show that the increased tissue PSA levels are correlated with lower cell apoptosis index and higher cell proliferation rate in hormone-refractory tumor specimens. By stably transfecting PSA cDNA into various prostate cancer cell lines, we found that PSA could promote the growth of androgen receptor (AR)-positive CWR22rv1 and high-passage LNCaP (hormone-refractory prostate cancer cells) but not that of AR-negative PC-3 and DU145 cells. Surprisingly, the protease activity of PSA is not crucial for PSA to stimulate growth and promote AR transactivation. We further showed that increased PSA could enhance ARA70-induced AR transactivation via modulating the p53 pathway that results in the decreased apoptosis and increased cell proliferation in prostate cancer cells. Knockdown of PSA in LNCaP and CWR22rv1 cells causes cell apoptosis and cell growth arrest at the G(1) phase. In vitro colony formation assay and in vivo xenografted tumor results showed the suppression of prostate cancer growth via targeting PSA expression. Collectively, our findings suggest that, in addition to being a biomarker, PSA may also become a new potential therapeutic target for prostate cancer. PSA small interfering RNA or smaller molecules that can degrade PSA protein may be developed as alternative approaches to treat the prostate cancer.

Increased hepatic steatosis and insulin resistance in mice lacking hepatic androgen receptor

Early studies demonstrated that whole-body androgen receptor (AR)-knockout mice with hypogonadism exhibit insulin resistance. However, details about the mechanisms underlying how androgen/AR signaling regulates insulin sensitivity in individual organs remain unclear. We therefore generated hepatic AR-knockout (H-AR(-/y)) mice and found that male H-AR(-/y) mice, but not female H-AR(-/-) mice, fed a high-fat diet developed hepatic steatosis and insulin resistance, and aging male H-AR(-/y) mice fed chow exhibited moderate hepatic steatosis. We hypothesized that increased hepatic steatosis in obese male H-AR(-/y) mice resulted from decreased fatty acid beta-oxidation, increased de novo lipid synthesis arising from decreased PPARalpha, increased sterol regulatory element binding protein 1c, and associated changes in target gene expression. Reduced insulin sensitivity in fat-fed H-AR(-/y) mice was associated with decreased phosphoinositide-3 kinase activity and increased phosphenolpyruvate carboxykinase expression and correlated with increased protein-tyrosine phosphatase 1B expression.

CONCLUSION

Together, our results suggest that hepatic AR may play a vital role in preventing the development of insulin resistance and hepatic steatosis. AR agonists that specifically target hepatic AR might be developed to provide a better strategy for treatment of metabolic syndrome in men.

Infertility with defective spermatogenesis and steroidogenesis in male mice lacking androgen receptor in Leydig cells

Androgen and the androgen receptor (AR) have been shown to play critical roles in male fertility. Our previous data demonstrated that mice lacking AR (AR(-/y)) revealed incomplete germ cell development and lowered serum testosterone levels, which resulted in azoospermia and infertility. However, the consequences of AR loss in Leydig cells remain largely unknown. Using a Cre-LoxP conditional knockout strategy, we generated a tissue-specific knockout mouse (L-AR(-/y)) with the AR gene deleted by the anti-Müllerian hormone receptor-2 (Amhr2) promoter driven Cre expressed in Leydig cells. Phenotype analyses show that the outside appearance of L-AR(-/y) mice was indistinguishable from wild type mice (AR(+/y)), but with atrophied testes and epididymis. L-AR(-/y) mice were infertile, with spermatogenic arrest predominately at the round spermatid stage and no sperm could be detected in the epididymis. L-AR(-/y) mice also have lower serum testosterone concentrations and higher serum leuteinizing hormone and follicle-stimulating hormone concentrations than AR(+/y) mice. Further mechanistic studies demonstrated that hypotestosteronemia in L-AR(-/y) mice is not caused by reducing numbers of Leydig cells, but instead by the alterations of several key steroidogenic enzymes, including 17beta-HSD3, 3beta-HSD6, and P450c17. Together, L-AR(-/y) mice provide in vivo evidence that functional AR in Leydig cells is essential to maintain normal spermatogenesis, testosterone production, and required for normal male fertility.

Increased prostate cell proliferation and loss of cell differentiation in mice lacking prostate epithelial androgen receptor

Developmental studies of the prostate have established that ductal morphogenesis, epithelial cytodifferentiation, and proliferation/apoptosis are regulated by androgens acting through stromal androgen receptor (AR). Here, we found mice lacking epithelial AR within the mature prostate (pes-ARKO) developed prostate tissue that was less differentiated and hyperproliferative relative to WT littermates. Epithelial AR protein was significantly decreased in 6-week-old mice and was nearly absent by >/=24 weeks of age. Circulating levels of testosterone, external genitalia, or fertility were not altered in pes-ARKO mice. A significant (P < 0.05) increase in bromo-deoxyuridine-positive epithelia was observed in ventral and dorsal-lateral prostates of pes-ARKO mice at 24 weeks of age. Less differentiation was observed as indicated by decreased epithelial height and glandular infolding through 24 weeks of age, differentiation markers probasin, PSP-94, and Nkx3.1 were sig nificantly decreased, and epithelial sloughing and luminal cell apoptosis increased from 6 to 32 weeks of age in pes-ARKO mice. Gain of function occurred by crossing pes-ARKO to the T857A transgenic mice containing constitutively activated AR. In T857A-pes-ARKO mice prostates were of normal size, contained glandular infoldings, and maintained high secretory epithelium, and the appropriate prostatic epithelial proliferation was restored. Collectively, these results suggest that prostatic epithelial AR plays an important role in the homeostasis of the prostate gland. These data support the hypothesis that epithelial AR controls prostate growth by suppressing epithelial proliferation in the mature gland.

Cutting edge: Th17 and regulatory T cell dynamics and the regulation by IL-2 in the tumor microenvironment

Th17 cells play an active role in inflammation and autoimmune diseases. However, the nature and regulation of Th17 in the context of tumor immunity remain unknown. In this study, we show that parallel to regulatory T (Treg) cells, IL-17(+) CD4(+) and CD8(+) T cells are kinetically induced in multiple tumor microenvironments in mice and humans. Treg cells play a crucial role in tumor immune pathogenesis and temper immune therapeutic efficacy. IL-2 is crucial for the production and function of Treg cells. We now show that IL-2 reduces IL-17(+) T cell differentiation in the tumor microenvironment accompanied with an enhanced Treg cell compartment in vitro and in vivo. Altogether, our work demonstrates a dynamic differentiation of IL-17(+) T cells in the tumor microenvironment, reveals a novel role for IL-2 in controlling the balance between IL-17(+) and Treg cells, and provides new insight of IL-17(+) T cells in tumor immune pathology and therapy.

Expression of human AR cDNA driven by its own promoter results in mild promotion, but not suppression, of growth in human prostate cancer PC-3 cells

AIM

To examine the physiological role of the androgen receptor (AR) in the PC-3 cell line by transfecting full-length functional AR cDNA driven by its natural human AR promoter.

METHODS

We generated an AR-expressing PC-3(AR)9 stable clone that expresses AR under the control of the natural human AR promoter and compared its proliferation to that of the PC-3(AR)2 (stable clone that expresses AR under the control of the cytomegalovirus (CMV) promoter, established by Heisler et al.) after androgen treatment.

RESULTS

We found that dihydrotestosterone (DHT) from 0.001 nmol/L to 10 nmol/L induces cell cycle arrest or inhibits proliferation of PC-3(AR)2 compared with its vector control, PC-3(pIRES). In contrast, PC-3(AR)9 cell growth slightly increased or did not change when treated with physiological concentrations of 1 nmol/L DHT.

CONCLUSION

These data suggest that intracellular control of AR expression levels through the natural AR promoter might be needed for determining AR function in androgen-independent prostate cancer (AIPC) PC-3 cells. Unlike previous publications that showed DHT mediated suppression of PC-3 growth after transfection of viral promoter-driven AR overexpression, we report here that DHT-mediated PC-3 proliferation is slightly induced or does not change compared with its baseline after reintroducing AR expression driven by its own natural promoter, as shown in PC-3(AR)9 prostate cancer cells.

Induction of androgen receptor expression by phosphatidylinositol 3-kinase/Akt downstream substrate, FOXO3a, and their roles in apoptosis of LNCaP prostate cancer cells

The phosphatidylinositol 3-kinase (PI3K)/Akt pathway plays important roles for prostate cancer cell survival, and the androgen receptor (AR) plays essential roles for prostate cancer cell proliferation. How these two signals cooperate to control cell growth and death, however, remains unclear and debated. Here we provide the first linkage by the identification of Forkhead transcription factor FOXO3a, the PI3K/Akt downstream substrate, as a positive regulator for the induction of AR gene expression. Both Western blot and real time PCR assays demonstrate that FOXO3a can induce AR expression at the protein and mRNA levels, and gel shift and chromatin immunoprecipitation assays further demonstrate that FOXO3a can induce 5' AR promoter activity via binding to the consensus DNA-binding sequence in the AR 5' promoter -1290 to -1297 (5'-TTGTTTCA-3'). Under normal growth conditions, blocking PI3K/Akt signals by LY294002 causes LNCaP cell arrest in G1 phase rather than apoptosis. However, further blocking of AR functions by AR small interfering RNA leads to dramatic LNCaP cell death, suggesting that AR may play important protective roles when the PI3K/Akt signal pathway is blocked by LY294002. Together, our data provide the first model to explain how PI3K/Akt and AR can cooperate to control LNCaP cell growth and death under normal conditions.

9-cis-Retinoic Acid Inhibits Androgen Receptor Activity through Activation of Retinoid X Receptor

Although the retinoic X receptor (RXR) forms heterodimers with many members of the estrogen receptor subfamily, the interaction between RXR and the members of the glucocorticoid receptor subfamily remains unclear. Here we show that the RXR can form a heterodimer with the androgen receptor (AR) under in vitro and in vivo conditions. Functional analyses further demonstrated that the AR, in the presence or absence of androgen, can function as a repressor to suppress RXR target genes, thereby preventing the RXR binding to the RXR DNA response element. In contrast, RXR can function as a repressor to suppress AR target genes in the presence of 9-cis-retinoic acid, but unliganded RXR can function as a weak coactivator to moderately enhance AR transactivation. Together, these results not only reveal a unique interaction between members of the two nuclear receptor subfamilies, but also represent the first evidence showing a nuclear receptor (RXR) may function as either a repressor or a coactivator based on the ligand binding status.

Inhibition of beta-oxidative respiration is a therapeutic window associated with the cancer chemo-preventive activity of PPARgamma agonists

We demonstrate expression and coordinate induction of PPARgamma and lipogenic enzymes (HMG-CoA synthase, HMG-CoA reductase and fatty acid synthase) in a murine lung alveolar carcinoma cell line (Line 1) treated with the PPARgamma agonist troglitazone (TRO) [0-100 microM]. We postulate that TRO induces a shift in cellular energy metabolism towards fatty acid oxidation (beta-oxidative respiration). Accordingly, co-treatment with TRO [30 microM] and increasing concentrations of trimetazidine (TMZ) [0.1-3 mM], an inhibitor of beta-oxidation, results in a dose dependent decrease cellular ATP levels and a dose dependent induction of apoptosis. These findings, suggest that inhibition of beta-oxidative respiration is a therapeutic window associated with the cancer chemo-preventive activity of PPARgamma agonists.

Inhibition of the Akt, cyclooxygenase-2, and matrix metalloproteinase-9 pathways in combination with androgen deprivation therapy: Potential therapeutic approaches for prostate cancer

Prostate cancer cells are generally dependent on androgen stimulation mediated by the androgen receptor (AR) for growth and survival, and, therefore, hormonal manipulation, such as castration and/or the use of AR antagonists, results in a regression of the cancer. However, this treatment very rarely leads to the "cure" of advanced disease, and cancers eventually become androgen-independent. A number of genes/pathways have been reported to be activated in prostate cancer, most of which are possibly associated with disease progression. In this article, among them, we focus on Akt (also known as protein kinase B), cyclooxygenase (COX)-2, and matrix metalloproteinase (MMP)-9, whose activities or expressions have been found to be regulated by androgens/AR. Previous studies by us and others, with androgen-sensitive prostate cancer cell lines, have demonstrated that androgen deprivation results in activation/overexpression of Akt, COX-2, and MMP-9 in cells. This suggests that androgen deprivation in clinical settings activates the Akt, COX-2, and MMP-9 pathways in prostate cancer, which may increase cell growth and in turn promote the transition to the androgen-independent state. We hypothesize that androgen deprivation, in combination with inhibition of the Akt, COX-2, and MMP-9 pathways, delays the androgen-independent transition and has more beneficial effects than hormonal therapy alone.

Identification of steroid derivatives that function as potent antiandrogens

We have hypothesized that some steroid derivatives bind to the androgen receptor (AR) with very low androgenic activity and therefore potentially function as better AR antagonists than clinically used antiandrogens, such as flutamide. Indeed, we previously found such a compound, 3beta-acetoxyandrosta-1,5-diene-17-one ethylene ketal (ADEK), with some estrogenic activity. Here we report the identification of 2 additional steroid derivatives, 3beta-hydroxyandrosta-5,16-diene (HAD) and androsta-1,4-diene-3,17-dione-17-ethylene ketal (OAK), as new potent antiandrogens. Like ADEK, HAD and OAK could interrupt androgen binding to the AR and suppress both dihydrotestosterone- and androstenediol-induced transactivations of wild-type and mutant ARs in prostate cancer cells. These 2 compounds also inhibited prostate-specific antigen expression in LNCaP as well as growth of different AR-positive prostate cancer cell lines stimulated by androgen. Significantly, HAD and OAK had only marginal agonist effects, as compared to hydroxyflutamide. More importantly, in contrast to ADEK, OAK was shown to possess marginal estrogenic activity. These results strengthen our hypothesis and suggest that selective steroid derivatives could be potent antiandrogenic drugs with less unfavorable effects for the treatment of prostate cancer.

Androgen receptor regulates expression of skeletal muscle-specific proteins and muscle cell types

C2C12 myoblasts expressing the androgen receptor (AR) were used to analyze the role of androgen-AR signaling pathway in skeletal muscle development. Marked up-regulation of AR expression was observed in differentiated myotubes. A nuclear run-on transcription assay demonstrated that transcription of the AR gene is increased during skeletal muscle cell differentiation. Regulation of skeletal muscle-specific protein expression by the androgen-AR signaling pathway was further analyzed using quadriceps skeletal muscle from wild-type (WT) and AR knock-out (ARKO) male mice. A histological analysis of quadriceps skeletal muscle indicates no morphological differences between ARKO and WT mice. However, the androgen-AR signaling pathway increases expression of slow-twitch-specific skeletal muscle proteins and downregulates fast-twitch-specific skeletal muscle proteins, resulting in an increase of slow-twitch muscle fiber type cells in quadriceps muscle.

RRR-alpha-tocopheryl succinate inhibits human prostate cancer cell invasiveness

RRR-alpha-tocopheryl succinate (alpha-vitamin E succinate, VES), one of the vitamin E derivatives, can effectively inhibit the proliferation of human prostate cancer cells. However, little is known about its effect on prostate cancer cell invasive ability. Tumor metastasis is a complex process and the extracellular matrix (ECM) is the first barrier that tumor cells encounter. Therefore, we tested the effect of VES on the invasion of different prostate tumor cells, PC-3, DU-145, and LNCaP, through Matrigel, a reconstituted ECM, using an in vitro cell invasion assay. The invasion of PC-3 and DU-145 cells through Matrigel was inhibited by 20 microM VES after treating for 24 h. The condition did not alter cell survival, cell cycle, cell adhesion or cell motility. We further investigated whether the ability of VES to inhibit prostate cancer cell invasiveness was associated with its ability to inhibit the activity of matrix metalloproteinases (MMPs), the key enzymes in the proteolysis of basement membrane during invasion. PC-3 and DU-145 cells that were treated with VES showed a significant reduction in the levels of MMP-9 in the culture medium. In contrast, LNCaP cells, which did not secrete MMP-9, were poorly invasive in Matrigel and were hardly affected by treatment with VES. This is the first report suggesting that VES inhibits human prostate cancer cell invasiveness and the reduction of secreted MMP-9 activity could be one of the contributory factors, which points to the potential use of VES in the prevention and therapy of prostate cancer invasion.

Androgen suppresses PML protein expression in prostate cancer CWR22R cells

The ability of PML to modulate key suppressive pathways in tumor cells suggests that PML may act as a tumor suppressor. The detailed mechanism of how PML functions in prostate cancer progression, however, remains unknown. Here we demonstrate that in the presence of androgen, PML protein expression can be suppressed in CWR22R prostate cancer cells. Further studies reveal that PML can selectively suppress AR transactivation and PML protein expression positively correlates with increased p21 protein level and enhances p53 transcription ability in CWR22R cells. We also found that PML strongly inhibits CWR22R cell colony formation, while PML siRNA enhances AR activity and CWR22R cell colony formation. Together our results suggest that PML may suppress prostate cancer cell growth by inhibiting AR transactivation and/or enhancing p53 activity.

Interruption of nuclear factor kappaB signaling by the androgen receptor facilitates 12-O-tetradecanoylphorbolacetate-induced apoptosis in androgen-sensitive prostate cancer LNCaP cells

12-O-tetradecanoylphorbolacetate (TPA) influences proliferation, differentiation, and apoptosis in a variety of cells including prostate cancer cells. Here, we show that androgen treatment potentiates TPA-induced apoptosis in androgen-sensitive prostate cancer LNCaP cells but not in androgen-independent prostate cancer cell lines DU145 and PC-3. The use of the antiandrogen bicalutamide (Casodex) rescued LNCaP cells from 5-alpha-dihydrotestosterone (DHT)/TPA-induced apoptosis, suggesting that DHT/TPA-induced apoptosis is mediated by androgen/androgen receptor (AR). In addition, a caspase-3 inhibitor (Ac-DEVD-CHO) reduced the level of apoptosis, suggesting that DHT/TPA-mediated apoptosis occurs through a caspase-3-dependent pathway. A functional reporter assay using nuclear factor (NF) kappaB-luciferase and an electromobility gel shift assay showed that DHT suppressed NFkappaB activity. In addition, apoptosis mediated by combined DHT/TPA treatment was abrogated by overexpression of the NFkappaB subunit p65 in LNCaP-p65 cells, suggesting that NFkappaB may play an important role in regulating the effects of androgen/AR and TPA on apoptosis. Furthermore, use of the c-Jun N-terminal kinase (JNK) inhibitor SB202190 showed that the combination of DHT/TPA increased JNK activation in LNCaP cells but not in LNCaP-p65 cells, demonstrating that NFkappaB may be able to suppress JNK activity. These results indicate that androgen/AR facilitates TPA-induced apoptosis by interruption of the NFkappaB signaling pathway, leading to activation of JNK in LNCaP cells. These data describe a signaling pathway that could potentially be useful in proposed therapeutic treatment strategies exploiting combinations of different agents that control apoptosis in prostate tumors.