Optimization of the supercritical fluidized bed process for sirolimus coating and drug release.

Directly coating an active pharmaceutical ingredient (API) onto excipient granules has been a common approach to prepare solid dosage forms. The combination of supercritical anti-solvent (SAS) and fluidized bed (FB) coating technology (SAS-FB) has the advantages of preventing nanoparticles aggregation, oxidation and light exposure. However individual operating parameters and factors which contribute to the overall coating efficiency remain to be defined. Sirolimus is an immunosuppressive agent for preventing the rejection of organ transplants and this drug is sensitive to light exposure and high temperature. Our study used sirolimus as the model API to evaluate parameters including temperature, pressure, drug concentration, mass, material and diameter of carrier, CO2 flow rate and solvent in the SAS-FB process. By optimizing these parameters, we achieved a 3.5-fold enhancement of the coating efficiency over the standard condition. A series of characterizations of the sirolimus coated particles were performed from which scanning electron microscopy and Raman mapping confirmed that the sirolimus particles were uniformly coated on carriers as cuboid particles; X-ray powder diffraction showed that processed sirolimus is crystalline but has lower crystallinity than the API, and fourier transform infrared spectroscopy and differential scanning calorimeter confirmed that there is no chemical interaction between sirolimus and carriers after SAS-FB processing. Finally compared to sirolimus alone, sirolimus coated particles displayed a faster dissolution and higher bioavailability. Collectively, our optimized operation parameters for SAS-FB coating technique provide a useful guidance for achieving higher efficiency of drug coating and faster release rate of sirolimus pellets, which has the potential to apply to other APIs.

Lipido-sterolic extract of Serenoa repens (LSESr, Permixon) treatment affects human prostate cancer cell membrane organization.

The molecular mechanism by which the lipido-sterolic extract of Serenoa repens (LSESr, Permixon) affects prostate cells remains to be fully elucidated. In androgen-independent PC3 prostate cancer cells, the LSESr-induced effects on proliferation and apoptosis were evaluated by counting cells and using a FACScan cytofluorimeter. PC3 cells were stained with JC-1 dye to detect mitochondrial membrane potential. Cell membrane lipid composition was evaluated by thin layer chromatography and gas chromatographic analysis. Akt phosphorylation was analyzed by Western blotting and cellular ultrastructure through electron microscopy. LSESr (12.5 and 25 microg/ml) administration exerted a biphasic action by both inhibiting proliferation and stimulating apoptosis. After 1 h, it caused a marked reduction in the mitochondrial potential, decreased cholesterol content and modified phospholipid composition. A decrease in phosphatidylinositol-4,5-bisphosphate (PIP2) level was coupled with reduced Akt phosphorylation. After 24 h, all of these effects were restored to pre-treatment conditions; however, the saturated (SFA)/unsaturated fatty acid (UFA) ratio increased, mainly due to a significant decrease in omega 6 content. The reduction in cholesterol content could be responsible for both membrane raft disruption and redistribution of signaling complexes, allowing for a decrease of PIP2 levels, reduction of Akt phosphorylation and apoptosis induction. The decrease in omega 6 content appears to be responsible for the prolonged and more consistent increase in the apoptosis rate and inhibition of proliferation observed after 2-3 days of LSESr treatment. In conclusion, LSESr administration results in complex changes in cell membrane organization and fluidity of prostate cancer cells that have progressed to hormone-independent status.

Transforming growth factor beta 1 and androgen receptors in prostate neoplasia.

OBJECTIVE: To investigate the interplay between transforming growth factor (TGF) beta 1, androgen receptors and stromal-epithelial interactions in benign prostatic hyperplasia (BPH), prostate intraepithelial neoplasia (PIN) and prostate carcinoma areas of prostate neoplasia. STUDY DESIGN: In this immunohistochemical study we investigated staining patterns and then determined the correlation between TGF-beta 1 expression and androgen receptor status in the epithelium and stroma of 60 paraffin-embedded tissues from radical prostatectomies. RESULTS: Staining patterns differed in the epithelium and stroma of tumor and peritumor prostatic tissue. TGF-beta 1 immunostaining (H-scores) in the epithelium and stroma increased significantly from BPH to PIN and from BPH to prostate carcinoma in the epithelium (P < .05), whereas androgen receptor (AR) immunoreactivity significantly (P < .05) increased from BPH to PIN to prostatic carcinoma in epithelium and stroma. TGF-beta 1 did not correlate with histologic grade of differentiation, whereas AR proteins were more strongly expressed in Gleason score 5 and 6 than score 7 tumors (P < .05). Nonlinear regression showed a significant correlation (P < .01) between TGF-beta 1 and AR expression only in the stromal compartment of PIN. CONCLUSION: These findings argue in favor of an interaction between TGF-beta 1 and AR in the early stages of prostate carcinogenesis and suggest that TGF-beta 1 plays a central role in stromal-epithelial interactions during the early stages of malignant transformation.

Effects of triptorelin, a gonadotropin-releasing hormone agonist, on the human prostatic cell lines PC3 and LNCaP.

Some analogues of gonadotropin-releasing hormone (GnRH) influence the in vitro proliferation of cultured human cells by complex interactions that are only partially understood. This study explored the effect of Triptorelin, a GnRH agonist, on the LNCaP and PC3 prostatic cell lines, which are, respectively, responsive and unresponsive to androgen stimulation. The toxicity and cell cycle modifications induced by the drug were investigated by FACScan analysis; the effect on cell proliferation in different culture conditions was determined by counting in a Burker chamber; and the expression of binding sites for 125I-Triptorelin was revealed by displacement experiments. PC3 cell growth was completely unaffected by Triptorelin. The drug caused a double stimulatory-inhibitory action on the growth of actively proliferating LNCaP cells, depending upon the dose and environment. A significant inhibitory effect on proliferation, ranging from 25% to 65% compared with controls, was observed at a high dose (10(-4) M) according to the culture conditions; and a proliferative effect (42% compared with controls) was observed at a lower dose (10(-7) M) only in fetal bovine serum-supplemented medium. Displacement experiments revealed the expression of moderately high affinity and low affinity binding sites in LNCaP cells (Kd = 2.6 x 10(-8) and 7.7 x 10(-6) M) but only low affinity binding sites in PC3 cells (Kd = 2.7 x 10(-6) M), which suggests that the expression of binding sites with different affinity could be associated with a biological response to the drug. Proliferation studies in the presence of Cetrorelix, a GnRH antagonist, confirmed the different sensitivity of the 2 cell lines to GnRH analogues and showed that the proliferative effect of Triptorelin on LNCaP cells can be inhibited by the antagonist. Data confirm the cell specificity of Triptorelin's action and the peculiarity of its effects on prostatic cell proliferation in our experimental conditions.

Identification of an estrogen-mediated deoxyribonucleic acid-binding independent transactivation pathway on the epidermal growth factor receptor gene promoter.

To investigate the estrogenic effects on the transcriptional regulation of the epidermal growth factor (EGF) receptor (EGFR) gene, we assayed its promoter ability to direct transcription of the luciferase reporter gene after transfection into HeLa cells. Our studies demonstrated a dose-dependent activation of the EGFR gene transcription by ligand-bound estrogen receptor alpha (ERalpha). This action was retained by the 36-bp core promoter fragment and did not require the receptor DNA binding domain, as demonstrated by analyzing the role of ERalpha deletion mutants on EGFR gene promoter-derived constructs. The 36-bp promoter fragment does not contain an estrogen response element but an imperfect thyroid hormone response element half-site that overlaps the Sp1 binding site. ERalpha does not bind this imperfect thyroid hormone response element half-site but is able to enhance binding of Sp1 to its site, in gel mobility shift assays, suggesting that the mechanism by which the receptor stimulated the transcription involved protein-protein interactions that replaced DNA binding. To explain this action, we propose a model in which induction of the EGFR gene expression by estrogens in HeLa cells is dependent upon the formation of a transcriptionally active ERalpha-Sp1 complex that binds to the GC-rich (Sp1) region of the minimal promoter.

Transforming growth factor-beta expression in prostate neoplasia.

OBJECTIVE: To understand the role of transforming growth factor (TGF) -beta 1, -beta 2 and -beta 3 proteins and TGF-beta type I and II receptors in prostate neoplasia; to determine the correlation between expression of TGF-beta s and their relative receptors in the epithelial and stromal compartments of benign prostatic hyperplasia (BPH), prostatic intraepithelial neoplasia (PIN) and prostate carcinoma; and to determine whether TGF-beta and TGF-beta receptor expression is associated with the grade of tumor differentiation. STUDY DESIGN: Sixty prostate neoplasms were analyzed by immunohistochemistry using anti-TGF-beta 1, -beta 2, -beta 3, -beta RI and -beta RII antibodies. RESULTS: TGF-beta and TGF-beta receptor immunoreactivity was more strongly expressed in prostate carcinoma than in PIN and BPH, and TGF-beta type I and type II receptors were less strongly expressed than TGF-beta 1-3 proteins. The difference between epithelial and stromal compartments reached significance (P < .05) for all TGF-beta isoforms and related receptors only in BPH, whereas a significant difference was found for TGF-beta protein in all grades of PIN but not for prostate carcinoma tissue. Luminal epithelial cells of BPH and PIN coexpressed all three TGF-beta isoforms and preferentially TGF-beta RII. Conversely, basal epithelial cells stained strongly for TGF-beta 1, -beta 3 and -beta RI but not for TGF-beta 2 and more strongly for TGF-beta RI than -beta RII. Linear regression showed a positive correlation between TGF-beta 1 and -beta 2, between TGF-beta 2 and -beta 3 and between TGF-beta RI and -beta RII proteins in all areas. The epithelium of Gleason score 7 tumors contained significantly higher TGF-beta 2 protein levels than Gleason score 3 and 4, and 5 and 6 tumors (P < .05). CONCLUSION: Stromal and epithelial cells of malignant and nonmalignant prostatic tumors express all three TGF-beta isoforms and their related receptors. These may act as both paracrine and autocrine factors to influence prostate function and the stromal-epithelial cell interaction. TGF-beta and -beta R immunoreactivity noted in basal cells indicates that in BPH and PIN, TGF-beta Rs and signaling pathways remain intact. The overexpression of TGF-beta proteins and underexpression of TGF-beta receptors in prostate cancer could suggest a mechanism for prostate cancer cells to escape the growth inhibitory effect of TGF-beta, thus leading to a more malignant phenotype.

Transforming growth factor-beta expression in human testicular neoplasms.

OBJECTIVE: To investigate the localization of transforming growth factors (TGF-beta 1, -beta 2 and -beta 3) and their receptors (TGF-beta RI and RII). STUDY DESIGN: The study included 26 paraffin-embedded tissues from human testicular neoplasms: 15 seminomas, 2 embryonal carcinomas, 1 immature teratoma, 4 immature teratomas with embryonal carcinoma, 1 immature teratoma with seminoma, 1 seminoma with embryonal carcinoma and 2 gonadal stromal tumors (Leydig cell tumors). RESULTS: TGF-beta 1 immunoreactivity was cytoplasmic and was expressed in 22 (84.6%), TGF-beta 2 in 20 (77%), TGF-beta 3 in 11 (42.3%), TGF-beta-RI in 21 (80.8%) and TGF-beta-RII in 18 (69.2%) of the 26 neoplasms. The percentage of positive immunostained cells and the intensity of staining were significantly higher in tumor than in peritumor nonneoplastic testis. In the peritumor nonneoplastic testis, Leydig, Sertoli and germ cells coexpressed both the three TGF-beta isoforms and TGF-beta-RI and RII. The myoepithelial cells of the seminiferous tubules showed immunoreactivity for TGF-beta RI and RII but not for TGF-beta s. In tumor testis areas the pattern of TGF-beta and TGF-beta receptor expression and distribution varied according to the histologic type of testicular tumor. Seminomas showed a diffuse pattern of TGF-beta immunoreactivity, whereas immature teratomas had focal and patchy distribution. In teratomas, differentiated structures contained more TGF-beta s than undifferentiated structures.

Androgen receptors in ovarian tumors: correlation with oestrogen and progesterone receptors in an immunohistochemical and semiquantitative image analysis study.

The expression and distribution of androgen, estrogen and progesterone receptors was examined by immunohistochemical staining in 31 paraffin-embedded sections from ovarian tumors and the results were assessed by semiquantitative image analysis. Immunohistochemical staining showed heterogeneous patterns of steroid receptor distribution, with mainly nuclear immunoreactivity. Eighty-four percent of benign and malignant ovarian tumors expressed androgen receptors (AR), 74.19% estrogen receptors (ER) and 41.16% progesterone receptors (PR). All benign tumors showed immunoreactivity for the three steroid receptors. Malignant tumors expressed higher AR and ER histochemical scores (H-scores) than PR (82% vs 71% vs 39%). The incidence and expression levels of the steroid receptors varied widely in the different histological types of malignant tumors. Spearman rank analysis showed a positive significant (P < 0.05) correlation between AR- and ER and between ER- and PR-H-scores. In malignant ovarian tumors, neither AR, ER nor PR immunohistochemical scores correlated with tumor FIGO stage. Densitrometric analysis of immunostained steroid receptors is a valid method for assessing the steroid status, because it reduces subjective elements in scoring sections and increases the reliability of results. The high incidence of AR expression confirms the functional role of AR in ovarian tumors and suggests that the determination of AR content in ovarian cancer could have prognostic value.

Effects of the lipidosterolic extract of Serenoa repens (Permixon) on human prostatic cell lines.

BACKGROUND: Permixon is a drug used in the treatment of benign prostatic hyperplasia. We studied its androgenic and antiandrogenic effects in the prostatic cell lines LNCaP and PC3, respectively responsive and unresponsive to androgen stimulation. METHODS: We performed FACScan analysis to investigate toxicity, 3H thymidine and 35S methionine incorporation to determine antiproliferative and metabolic effects, electron microscopy to study ultrastructural changes and cotransfection experiments to elucidate the role of wild type androgen receptor. RESULTS: In LNCaP cell line, Permixon induced a double proliferative/differentiative effect, not observed in PC3 cells. In PC3 cells cotransfected with wild-type androgen receptors and CAT reporter genes under the control of a androgen responsive element, the drug inhibited androgen-induced CAT transcription. CONCLUSIONS: Our data indicate a role of the androgen receptor in mediating the effects of Permixon in LNCaP cells. Cotransfection experiments in PC3 cells support a clear antiandrogenic action of the drug.

Gene methylation of oestrogen and epidermal growth factor receptors in neoplastic and perineoplastic breast tissues.

Oestrogen receptor (ER) and epidermal growth factor receptor (EGFR) gene methylation was evaluated in neoplastic and perineoplastic breast tissues from 20 patients. In both tissues, ER gene methylation was inversely correlated with protein levels, while EGFR gene methylation was not. A preferential ER gene hypomethylation was found in neoplastic tissues, suggesting a significant role in neoplastic transformation.

Androgenic and antiandrogenic control on epidermal growth factor, epidermal growth factor receptor, and androgen receptor expression in human prostate cancer cell line LNCaP.

Both androgen and antiandrogen treatments enhance the proliferation rate of the hormone-dependent prostate cancer cell line LNCaP, expressing a mutated androgen receptor (AR). We studied the modification of the expression of epidermal growth factor (EGF), of its receptor (EGF-R), and of androgen receptor (AR) in the LNCaP cell line, under basal conditions and during androgen (R1881) and antiandrogen hydroxy-flutamide (OH-FLU) treatment. After prolonged R1881 administration, a marked increase of EGF release was observed, completely blocked by the addition of OH-FLU. The Scatchard plot analysis of EGF-R binding revealed two classes of binding sites with high and low affinity. The administration of OH-FLU alone or combined with R1881 did not modify the affinity constants, while the low-affinity component disappeared after androgen administration. Both androgen and antiandrogen administration led to a significant increase of the EGF-R high-affinity component. AR mRNA and protein levels were downregulated by R1881 treatment. Following OH-FLU administration, AR mRNA was slightly downregulated, and there was not a strict parallelism between AR mRNA levels and AR binding capacity. When combined with R1881, OH-FLU partially counteracted the androgen-induced AR downregulation. Our data show that EGF-R binding capacity is the only parameter constantly raised in cell proliferation with respect to quiescent cells, and highlights the nonunivocal action of OH-FLU on androgen-induced effects.

Estrogen receptors: new perspectives in breast cancer management.

The imbalance between proliferative and differentiative estrogenic effect, caused by quantitative and qualitative alteration of the estrogen receptor (ER) expression, may play a determinant role in mammary neoplastic transformation. Our studies demonstrate that ER levels are significantly higher in human mammary neoplastic tissues when compared to perineoplastic tissues and that increased ER expression is associated with ER gene hypomethylation. During progressive multifactorial carcinogenesis, ER overexpression may represent an early step in neoplastic transformation. In fact, high levels of ER represent good markers of differentiation and can predict the likelihood of benefiting from anti-estrogen therapy. Nevertheless, about 35% of ER-positive breast cancers are resistant to endocrine therapy and 10% of ER-negative tumors behave as hormone-sensitive tumors. Recent studies on ER mRNA variants, which naturally occur in human breast tumors, demonstrated mutations, deletions and alternative splicings, yielding deletions of exons 3, 4, 5 and 7. ER variants exhibited altered functions or changed the responsiveness to hormonal therapy. Analysis of these variants could be a useful parameter to better predict tumor responsiveness to anti-estrogen therapy. Recently, a regain of hormonal responsiveness by ER-negative breast cancer cells has been reported following ER gene transfection. However, estradiol treatment inhibits rather than stimulates cell growth as well as the metastatic and invasive potential of the ER gene transduced cells. Transfer of the ER gene may be considered as a new therapeutic approach in the management of hormone-independent breast cancer.

Inheritance of ribosomal gene activity and level of DNA methylation of individual gene clusters in a three generation family.

Ribosomal gene activity and levels of DNA methylation were investigated by cytochemical and immunological methods in the nucleolar organizer regions (NORs) of individually recognised acrocentric chromosomes. Mendelian inheritance of ribosomal gene activity in a three generation family was demonstrated, together with consistent behaviour of individual gene clusters in different carriers, even when environmental conditions were changed. For most chromosomes, an inverse relationship between gene activity and the level of DNA methylation was observed. Exceptions were the two chromosomes 15 and chromosomes 13cp and 22p, all being strongly chromomycin-A3-positive in their short arms. These chromosomes bound to anti-5-MeC antibodies with differential frequencies in the different carriers. The possibility of involvement of repetitive GC-rich DNA in this behaviour is discussed.

Laron dwarfism: cellular unresponsiveness to GH demonstrated on cultured lymphocytes by a cytochemical method.

The response to growth hormone (GH) of cultured lymphocytes from three patients with Laron dwarfism (LD), one subject with growth hormone deficiency and a normal adult volunteer was examined by employing the cytochemical method of selective silver staining that evidentiates the chromosomal sites of those gene clusters (Nucleolus Organizers, NOs) which are actively involved in rRNA transcription. Lymphocytes from the normal donor responded to GH administration with a significant increase of the mean number of silver positive NOs per cell as well as lymphocytes from the growth hormone deficient patient (P less than 0.001). No response to GH administration was observed in lymphocytes from any of the three subjects with LD. These results suggest that the technique of selective silver staining of NOs can be usefully applied to the study of those growth disorders in which a peripheral unresponsiveness to GH is suspected, as demonstrated by data obtained on lymphocytes from patients with LD. This method seems to offer considerable potentialities for studying the cellular response also to other hormones and environmental stimuli.

Differential ribosomal gene responsiveness to human growth hormone is visualized by selective silver staining.

Differential activity of rRNA gene clusters following growth-hormone administration has been demonstrated in cultured lymphocytes from subjects with different genetic backgrounds, i.e., with or without in vivo peripheral responsiveness to the hormone. The influence of different culture conditions on ribosomal gene responsiveness was also tested. Ribosomal gene activity was evaluated by selective silver staining of nucleolus organizing regions. The results show that hormone-induced enhancement of transcriptional activity requires both genetically determined cell responsiveness and environmentally determined permissive factors.

Effects of uneven elastic loads on breathing pattern of anesthetized and conscious men.

In anesthetized subjects rib cage strapping (RCS) did not change tidal volume (VT) and increased ventilation (V), whereas abdomen strapping (AS) markedly decreased VT and V. Both kinds of strapping decreased expiratory duration (TE), but did not change inspiratory duration (TI) and breathing rate. RCS and AS decreased lung volume by about 200 ml and increased the elastance of the repiratory system by 12 cm H2O/1 and 9 CM H20/l, repectively. The changes produced are mainly due to mechanical factors, although reflexes also seem to be operating in some cases. In conscious subjects RCS decreased VT, TI, TE and did not change V, whereas AS did not change these parameters. The different changes in conscious and anesthetized subjects show the effects of cortical influences, which also partly explain the differen effects elicited in conscious subjects by RCS and AS. The effects produced by RCS are mainly due to the sensation of hindrance to rib cage expansion, rather than to that of rib cage squeezing, as shown by experiments of RCS without reduction of rib cage volume.