cyclin-d1 and bicalutamide

Mammary serine protease inhibitor or Maspin has been characterized as a class II tumor suppressor gene in several cancer types, among them prostate cancer (CaP). Androgen ablation is an effective therapy for CaP, but with short-term effectiveness, thus new therapeutic strategies are actively sought. The present study is aimed to explore the effects of a glucosamine derivative, 2-(N-Carbobenzyloxy)l-phenylalanylamido-2-deoxy-β-d-glucose (NCPA), on two CaP cell lines, PC3 and LNCaP. In particular we analyzed the impact of NCPA on Maspin production, cell viability and cell cycle progression and apoptosis/necrosis pathway activation in PC3 and LNCaP cell lines. NCPA is able to stimulate Maspin production in PC3 and not in LNCaP cell lines. NCPA blocks the PC3 cell cycle in G1 phase, by inhibiting Cyclin D1 production and induces the apoptosis, therefore interfering with aggressiveness of this androgen-insensitive cell line. Moreover, NCPA is able to induce the expression of Maspin in LNCaP cell line treated with androgen receptor inhibitor, Bicalutamide, and in turn to stimulate the apoptosis of these cells. These findings suggest that NCPA, stimulating the endogenous production of a tumor suppressor protein, could be useful in the design of new therapeutic strategies for treatment of CaP.

Topics: Anilides; Cell Cycle Checkpoints; Cell Line, Tumor; Cell Proliferation; Cell Survival; Cyclin D1; Glucosamine; Humans; Male; Nitriles; Prostatic Neoplasms; Receptors, Androgen; Serpins; Tosyl Compounds

The aims of this study were to examine the expression of androgen receptors (AR) in oral squamous cell carcinoma (OSCC) cells and tumors and to determine the role of AR in regulating OSCC cell growth.. Four OSCC cell lines were used for analyzing AR expression and transcriptional activity. The effects of AR knockdown on the growth and tumorigenicity of OSCC cells were examined. A series of 11 benign, 22 premalignant, and 21 malignant lesions of the oral cavity were used for analyzing AR expression.. OSCC cells expressed AR proteins with differential activities. Stimulation of AR by dihydrotestosterone in OSCC cells caused an increase in cyclin D1 expression and promoted cell growth, whereas treatment with bicalutamide led to decreased cyclin D1 expression and inhibited cell growth. Knockdown of AR expression in OSCC cells resulted in decreased proliferation, increased apoptosis, and inhibited tumorigenicity. Results from immunohistochemical studies showed that AR immunoreactivity was found in 27% (3/11) of benign lesions, while 68% (15/22) of premalignant and 67% (14/21) of malignant lesions showed positive AR staining.. Our data suggest that OSCC cells express functional AR proteins which are critical for promoting cell growth and causing malignant disease.

Topics: Androgen Antagonists; Androgens; Anilides; Animals; Apoptosis; Carcinoma, Squamous Cell; Cell Line, Tumor; Cell Proliferation; Cell Transformation, Neoplastic; Cyclin D1; Dihydrotestosterone; Gene Knockdown Techniques; Humans; Mice; Mouth Neoplasms; Nitriles; Precancerous Conditions; Receptors, Androgen; Tosyl Compounds

It has been noticed that crosstalk between androgen receptor (AR) and mammalian target of rapamycin (mTOR) signaling pathways plays a crucial role in the proliferation of prostate cancer cells. To clarify this mechanism, we focused on DEPTOR, a naturally occurring inhibitor of mTOR. The treatment of a human AR-positive prostate cancer cell line, LNCaP, with the AR-agonist dihydrotestosterone (DHT) repressed DEPTOR mRNA expression in a time-dependent manner. This repression was abrogated by treatment with the AR-antagonist bicalutamide. Knockdown of DEPTOR mRNA by siRNA resulted in the increased phosphorylation of 70 kDa ribosomal protein S6 kinase 1 (S6K), a substrate of mTORC1, accompanied by the elevated expression of cyclin D1, a positive regulator of cell proliferation. Furthermore, the ChIP assay demonstrated that AR could bind to AR-responsible element-like region within the 4th intron of the DEPTOR gene. The amount of acetylated histone H3 (Lys9, Lys14) was reduced by the DHT treatment in this region. Taken together, these results propose that AR-dependent prostate cancer cell proliferation requires decreased DEPTOR transcription directly controlled by AR.

Topics: Androgen Antagonists; Anilides; Cell Line, Tumor; Cell Proliferation; Cyclin D1; Dihydrotestosterone; Histones; Humans; Intracellular Signaling Peptides and Proteins; Male; Nitriles; Phosphorylation; Prostatic Neoplasms; Receptor Cross-Talk; Receptors, Androgen; Ribosomal Protein S6 Kinases, 70-kDa; RNA, Messenger; Signal Transduction; Time Factors; TOR Serine-Threonine Kinases; Tosyl Compounds; Transcription, Genetic; Tumor Cells, Cultured

Although a high frequency of androgen receptor (AR) expression in human breast cancers has been described, exploiting this knowledge for therapy has been challenging. This is in part because androgens can either inhibit or stimulate cell proliferation in pre-clinical models of breast cancer. In addition, many breast cancers co-express other steroid hormone receptors that can affect AR signaling, further obfuscating the effects of androgens on breast cancer cells.. To create better-defined models of AR signaling in human breast epithelial cells, we took estrogen receptor (ER)-α-negative and progesterone receptor (PR)-negative human breast epithelial cell lines, both cancerous and non-cancerous, and engineered them to express AR, thus allowing the unambiguous study of AR signaling. We cloned a full-length cDNA of human AR, and expressed this transgene in MCF-10A non-tumorigenic human breast epithelial cells and MDA-MB-231 human breast-cancer cells. We characterized the responses to AR ligand binding using various assays, and used isogenic MCF-10A p21 knock-out cell lines expressing AR to demonstrate the requirement for p21 in mediating the proliferative responses to AR signaling in human breast epithelial cells.. We found that hyperactivation of the mitogen-activated protein kinase (MAPK) pathway from both AR and epidermal growth factor receptor (EGFR) signaling resulted in a growth-inhibitory response, whereas MAPK signaling from either AR or EGFR activation resulted in cellular proliferation. Additionally, p21 gene knock-out studies confirmed that AR signaling/activation of the MAPK pathway is dependent on p21.. These studies present a new model for the analysis of AR signaling in human breast epithelial cells lacking ERα/PR expression, providing an experimental system without the potential confounding effects of ERα/PR crosstalk. Using this system, we provide a mechanistic explanation for previous observations ascribing a dual role for AR signaling in human breast cancer cells. As previous reports have shown that approximately 40% of breast cancers can lack p21 expression, our data also identify potential new caveats for exploiting AR as a target for breast cancer therapy.

Topics: Androgen Antagonists; Androgens; Anilides; Breast Neoplasms; Cell Line, Tumor; Cell Proliferation; Cyclin D1; Cyclin-Dependent Kinase Inhibitor p21; Enzyme Activation; Epithelial Cells; Estrogen Receptor alpha; Extracellular Signal-Regulated MAP Kinases; Female; Gene Expression; Humans; MAP Kinase Signaling System; Metribolone; Nitriles; Receptors, Androgen; Recombinant Proteins; Tosyl Compounds; Up-Regulation