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1.
Hand Surg Rehabil ; 42(2): 127-133, 2023 04.
Article in English | MEDLINE | ID: mdl-36764359

ABSTRACT

OBJECTIVES: The aim of this study was to compare the clinical and functional outcomes of three surgical techniques (subperiosteal suture, bone anchor and direct repair) for the management of severe acute ulnar collateral ligament injuries of the thumb metacarpophalangeal joint with a minimum of 1 year follow-up. MATERIAL AND METHODS: Between 2015 and 2020, 230 collateral ligament injuries required surgical treatment in our department. After the inclusion and exclusion criteria were applied, 100 were included in the study. The Glickel score and functional scores such as QuickDASH and PRWE were assessed. Time to return to work and to sport was quantified. RESULTS: Ulnar collateral ligament injuries affected men who were statistically younger than women (41.8 years old vs 48.3). Subperiosteal suture was the preferred technique (81%), then bone anchor reattachment (12%) and direct repair (7%). All three techniques produced excellent stability (91-100%). Better range of motion was reported in the subperiosteal group, but better strength was found in the bone anchor group. Subperiosteal suture had 89% excellent and good results, while there was 83% in the bone anchor group and 71% in the direct repair group. Mean time to return to work was 2 months in the bone anchor group versus 3 months in the subperiosteal group. Mean QuickDASH was 8.7/100 and mean PRWE was 7.1/100. CONCLUSION: This is the biggest case series to date on surgical treatment of severe ulnar collateral ligament injuries of the thumb metacarpophalangeal joint. The subperiosteal technique is simpler and less expensive. While the results are not often described in the literature, it produces comparable clinical and functional outcomes to bone anchor reattachment with a minimum follow-up of 1 year.


Subject(s)
Collateral Ligament, Ulnar , Metacarpophalangeal Joint , Thumb , Adult , Female , Humans , Male , Collateral Ligament, Ulnar/surgery , Collateral Ligament, Ulnar/injuries , Metacarpophalangeal Joint/surgery , Metacarpophalangeal Joint/injuries , Thumb/surgery , Thumb/injuries
2.
Regul Toxicol Pharmacol ; 113: 104651, 2020 Jun.
Article in English | MEDLINE | ID: mdl-32229245

ABSTRACT

Thousands of chemicals have limited, or no hazard data readily available to characterize human risk. The threshold of toxicological concern (TTC) constitutes a science-based tool for screening level risk-based prioritization of chemicals with low exposure. Herein we compare TTC values to more rigorously derived reference dose (RfD) values for 288 chemicals in the U.S. Environmental Protection Agency's (US EPA) Integrated Risk Information System (IRIS) database. Using the Cramer decision tree and the Kroes tiered decision tree approaches to determine TTC values, the TCC for the majority of these chemicals were determined to be lower than their corresponding RfD values. The ratio of log10(RfD/TCC) was used to measure the differences between these values and the mean ratio for the substances evaluated was ~0.74 and ~0.79 for the Cramer and Kroes approach, respectively, when considering the Cramer Classes only. These data indicate that the RfD values for Cramer Class III compounds were, on average, ~6-fold higher than their TTC value. These analyses indicate that provisional oral toxicity values might be estimated from TTCs in data-poor or emergency situations; moreover, RfD values that are well below TTC values (e.g., 2 standard deviations below the log10(Ratio)) might be overly conservative and targets for re-evaluation.


Subject(s)
Hazardous Substances/toxicity , Administration, Oral , Databases, Factual , Dose-Response Relationship, Drug , Hazardous Substances/administration & dosage , Humans , No-Observed-Adverse-Effect Level , Risk Assessment , United States , United States Environmental Protection Agency
3.
Food Chem Toxicol ; 132: 110718, 2019 Oct.
Article in English | MEDLINE | ID: mdl-31356915

ABSTRACT

Safety assessment for cosmetic-relevant chemicals (CRCs) in the European Union has been reshaped by restrictions on animal testing, and new approach methodologies (NAMs) for predicting toxicity are critical to ensure new cosmetic product safety. To demonstrate NAMs for safety assessment, we surveyed in vitro bioactivity and in vivo systemic toxicity data in the US Environmental Protection Agency's (EPA's) Toxicity Forecaster (ToxCast) and Toxicity Reference databases (ToxRefDB), respectively, for 58 chemicals identified as CRCs, including cosmetic ingredients as well as trace contaminants. CRCs were diverse in use types as suggested by broad chemical use categories. In terms of both target organ effects and study type, the median of the lowest effect level (LEL) doses in ToxRefDB for CRCs tended to be slightly higher than the median for the remaining 928 chemicals with study data in ToxRefDB, though the ranges of LELs were similar. For 17 of the 58 CRCs, high-throughput toxicokinetic data were used to calculate administered equivalent doses (AEDs) in mg/kg/day units for the in vitro bioactivity observed, and these AEDs served as conservative estimators of the systemic LELs observed in vivo. This work suggests that NAMs for bioactivity may inform a conservative point-of-departure estimate for diverse CRCs.


Subject(s)
Cosmetics/chemistry , Databases, Chemical , Animals , Humans , Retrospective Studies , United States , United States Environmental Protection Agency
4.
PLoS One ; 14(5): e0217564, 2019.
Article in English | MEDLINE | ID: mdl-31136631

ABSTRACT

Linking in vitro bioactivity and in vivo toxicity on a dose basis enables the use of high-throughput in vitro assays as an alternative to traditional animal studies. In this study, we evaluated assumptions in the use of a high-throughput, physiologically based toxicokinetic (PBTK) model to relate in vitro bioactivity and rat in vivo toxicity data. The fraction unbound in plasma (fup) and intrinsic hepatic clearance (Clint) were measured for rats (for 67 and 77 chemicals, respectively), combined with fup and Clint literature data for 97 chemicals, and incorporated in the PBTK model. Of these chemicals, 84 had corresponding in vitro ToxCast bioactivity data and in vivo toxicity data. For each possible comparison of in vitro and in vivo endpoint, the concordance between the in vivo and in vitro data was evaluated by a regression analysis. For a base set of assumptions, the PBTK results were more frequently better associated than either the results from a "random" model parameterization or direct comparison of the "untransformed" values of AC50 and dose (performed best in 51%, 28%, and 21% of cases, respectively). We also investigated several assumptions in the application of PBTK for IVIVE, including clearance and internal dose selection. One of the better assumptions sets-restrictive clearance and comparing free in vivo venous plasma concentration with free in vitro concentration-outperformed the random and untransformed results in 71% of the in vitro-in vivo endpoint comparisons. These results demonstrate that applying PBTK improves our ability to observe the association between in vitro bioactivity and in vivo toxicity data in general. This suggests that potency values from in vitro screening should be transformed using in vitro-in vivo extrapolation (IVIVE) to build potentially better machine learning and other statistical models for predicting in vivo toxicity in humans.


Subject(s)
Hepatocytes/metabolism , Liver/metabolism , Models, Biological , Animals , Hepatocytes/pathology , Humans , Liver/pathology , Metabolic Clearance Rate , Rats , Toxicokinetics
5.
Oncogene ; 31(9): 1105-16, 2012 Mar 01.
Article in English | MEDLINE | ID: mdl-21765463

ABSTRACT

The prognosis of patients with uveal melanoma is poor. Because of the limited efficacy of current treatments, new therapeutic strategies need to be developed. Because p53 mutations are uncommon in uveal melanoma, reactivation of p53 may be used to achieve tumor regression. We investigated the use of combination therapies for intraocular melanoma, based on the p53 activators Nutlin-3 and reactivation of p53 and induction of tumor cell apoptosis (RITA) and the topoisomerase I inhibitor Topotecan. Nutlin-3 treatment induced p53-dependent growth inhibition in human uveal melanoma cell lines. The sensitivity to Nutlin-3 of the investigated cell lines did not correlate with basal Hdm2 or Hdmx levels. Nutlin-3 synergized with RITA and Topotecan to induce apoptosis in uveal melanoma cell lines and short-term cultures. Drug synergy correlated with enhanced induction of p53-Ser46 phosphorylation, which was attenuated by ATM inhibition. Nutlin-3 and Topotecan also significantly delayed tumor growth in vivo in a murine B16F10 model for ocular melanoma. Combination treatment appeared to inhibit tumor growth slightly more efficient than either drug alone. Nutlin-3, RITA and Topotecan lead to comparable p53 activation and growth inhibition under normoxia and hypoxia. Treatment with Nutlin-3 or RITA had no effect on HIF-1α induction by hypoxia, whereas the combination of these two drugs did inhibit hypoxia-induced HIF-1α. Also Topotecan, alone or in combination with Nutlin-3, reduced HIF-1α protein levels, suggesting that a certain level of DNA damage response is required for p53-mediated downregulation of HIF-1α. In conclusion, combination treatments based on small-molecule-induced p53 activation may have clinical potential for uveal melanoma.


Subject(s)
Antineoplastic Agents/therapeutic use , Melanoma/drug therapy , Tumor Suppressor Protein p53/agonists , Uveal Neoplasms/drug therapy , Animals , Antineoplastic Agents/pharmacology , Apoptosis/drug effects , Apoptosis/genetics , Ataxia Telangiectasia Mutated Proteins , Cell Cycle Proteins/antagonists & inhibitors , Cell Line, Tumor , Cell Proliferation/drug effects , DNA-Binding Proteins/antagonists & inhibitors , Drug Synergism , Furans/pharmacology , Furans/therapeutic use , Humans , Hypoxia , Imidazoles/pharmacology , Imidazoles/therapeutic use , Melanoma/genetics , Melanoma, Experimental/drug therapy , Melanoma, Experimental/genetics , Mice , Phosphorylation/drug effects , Piperazines/pharmacology , Piperazines/therapeutic use , Protein Serine-Threonine Kinases/antagonists & inhibitors , Topotecan/pharmacology , Topotecan/therapeutic use , Tumor Suppressor Protein p53/genetics , Tumor Suppressor Proteins/antagonists & inhibitors , Uveal Neoplasms/genetics
6.
J Wound Care ; 17(11): 482, 484-6, 488 passim, 2008 Nov.
Article in English | MEDLINE | ID: mdl-18978687

ABSTRACT

There is little rigorous evidence on the management of epidermolysis bullosa, so management is based on the patient's and clinician's preferences. However, there is a consensus that advanced dressings help promote healing and reduce pain.


Subject(s)
Bandages , Epidermolysis Bullosa/therapy , Humans
8.
Clin Exp Immunol ; 139(2): 202-9, 2005 Feb.
Article in English | MEDLINE | ID: mdl-15654818

ABSTRACT

Our laboratory has demonstrated that down-regulation of proliferation and cytokine synthesis by CD4(+) T cells in mice fed diets rich in n-3 polyunsaturated fatty acids (PUFA) is highly dependent on the involvement of the co-stimulatory molecule, CD28. It has been reported that the inhibitory cytokine interleukin (IL)-10 acts directly on T cells which up-regulate IL-10 receptor (IL-10R) expression following stimulation via CD28 by efficiently blocking proliferation and cytokine production. Thus, it was hypothesized that dietary n-3 PUFA would suppress T cell function through the effects of IL-10. The proliferation of purified splenic CD4(+) T cells activated in vitro with anti-CD3 and anti-CD28 (alphaCD3/CD28) from conventional mice (C57BL/6) fed either a control corn oil (CO)-enriched diet devoid of n-3 PUFA, docosahexaenoic acid (DHA; 22 : 6) or eicosapentaenoic acid (EPA; 20 : 5) for 14 days was suppressed by dietary DHA and EPA. Surprisingly, a similar trend was seen in IL-10 gene knock-out (IL-10(-/-)) mice fed dietary n-3 PUFA. IL-10R cell surface expression was also significantly down-regulated on CD4(+) T cells from both the C57BL/6 and IL-10(-/-) mice fed dietary n-3 PUFA after 72 h of in vitro stimulation with alphaCD3/CD28. Enzyme-linked immunosorbent assay (ELISA) measurements revealed that C57BL/6 mice fed DHA had significantly reduced interferon (IFN)-gamma and IL-10 levels 48 h post-activation. However, CD4(+) T cells from IL-10(-/-) mice fed dietary n-3 PUFA produced significantly greater levels of IFN-gamma than the CO-fed group. Our data suggest that in the absence of IL-10, CD4(+) T cells from n-3 PUFA-fed mice may up-regulate IFN-gamma. Suppressed CD4(+) T cells from n-3 PUFA-fed C57BL/6 mice may use mechanisms other than IL-10 to down-regulate T cell function.


Subject(s)
CD4-Positive T-Lymphocytes/immunology , Dietary Fats, Unsaturated/administration & dosage , Fatty Acids, Omega-3/administration & dosage , Interleukin-10/immunology , Animals , CD28 Antigens/immunology , Cell Proliferation , Flow Cytometry , Interferon-gamma/analysis , Interferon-gamma/immunology , Interleukin-10/analysis , Mice , Mice, Inbred C57BL , Mice, Knockout
9.
J Hered ; 95(1): 11-8, 2004.
Article in English | MEDLINE | ID: mdl-14757725

ABSTRACT

The Vietnamese sika deer (Cervus nippon pseudaxis) is an endangered subspecies of economic and traditional value in Vietnam. Most living individuals are held in traditional farms in central Vietnam, others being found in zoos around the world. Here we study the neutral genetic diversity and population structure of this subspecies using nine microsatellite loci in order to evaluate the consequences of the limited number of individuals from which this population was initiated and of the breeding practices (i.e., possible inbreeding). Two hundred individuals were sampled from several villages. Our data show both evidence for limited local inbreeding and isolation by distance with a mean F(ST) value of 0.02 between villages. This suggests that exchange of animals occurs at a local scale, at a rate such that highly inbred mating is avoided. However, the genetic diversity, with an expected heterozygosity (H(e)) of 0.60 and mean number of alleles (k) of 5.7, was not significantly larger than that estimated from zoo populations of much smaller census size (17 animals sampled; H(e) = 0.65, k = 4.11). Our results also suggest that the Vietnamese population might have experienced a slight bottleneck. However, this population is sufficiently variable to constitute a source of individuals for reintroduction in the wild in Vietnam.


Subject(s)
Deer/genetics , Genetic Variation , Microsatellite Repeats/genetics , Animals , Breeding , Genetics, Population , Geography , Polymorphism, Genetic , Vietnam
10.
Antiviral Res ; 52(3): 251-9, 2001 Dec.
Article in English | MEDLINE | ID: mdl-11675142

ABSTRACT

The novel influenza virus neuraminidase (NA) inhibitor, (1S,2S,3R,4R)-3-[(1S)-(acetylamino)-2-ethylbutyl]-4-[(aminoiminomethyl)amino]-2-hydroxy-cyclopentanecarboxylic acid (RWJ-270201, BCX-1812), is a potent inhibitor of influenza A and B viruses in cell culture and in infected mice. A mouse-adapted strain of influenza A/Shangdong/09/93 (H3N2) virus was serially passaged in the presence of 1 microM compound. After the fourth passage, breakthrough of resistant virus occurred. By the tenth passage, a twice plaque purified isolate was obtained which could replicate in 10 microM inhibitor. The 50% effective concentration (EC(50)) values for RWJ-270201 against wild-type and resistant viruses, determined by using a cytopathic effect inhibition assay, were 0.007 and 23 microM, respectively. Cross-resistance to zanamivir and oseltamivir carboxylate was observed. The hemagglutinin (HA) and NA genes of the virus were sequenced to determine the mutation(s) which conferred drug resistance. No differences were found between the resistant and wild-type viruses in the NA gene. However, a point mutation resulting in a single amino acid change (Lys189Glu) was found in the resistant viral HA. The wild-type and resistant viruses were compared for virulence in BALB/c mice. The resistant virus was approximately tenfold less virulent than the wild-type virus based upon virus challenge dose. Mice infected with a lethal dose of the resistant virus could still be effectively treated with RWJ-270201. Thus, the HA mutation may allow for the spread of the virus in cell culture in the presence of the NA inhibitor, but not in mice.


Subject(s)
Antiviral Agents/pharmacology , Cyclopentanes/pharmacology , Drug Resistance, Viral , Influenza A Virus, H3N2 Subtype , Influenza A virus/enzymology , Influenza A virus/genetics , Neuraminidase/antagonists & inhibitors , Acids, Carbocyclic , Animals , Antiviral Agents/chemistry , Antiviral Agents/therapeutic use , Cell Line , Cell Line, Transformed , Cyclopentanes/chemistry , Cyclopentanes/therapeutic use , Dogs , Enzyme Inhibitors/chemistry , Enzyme Inhibitors/pharmacology , Enzyme Inhibitors/therapeutic use , Guanidines , Humans , Influenza A virus/drug effects , Influenza A virus/pathogenicity , Influenza, Human/drug therapy , Influenza, Human/virology , Mice , Mice, Inbred BALB C , Mutation/genetics , Virulence/genetics
11.
J Clin Endocrinol Metab ; 86(9): 4078-88, 2001 Sep.
Article in English | MEDLINE | ID: mdl-11549629

ABSTRACT

The efficacy and safety of androgen supplementation in older men remains controversial. Despite biochemical evidence of partial androgen deficiency in older men, controlled studies using T demonstrate equivocal benefits. Furthermore, the importance of aromatization and 5alpha reduction in androgen actions among older men remains unclear. Dihydrotestosterone is the highest potency natural androgen with the additional features that it is neither aromatizable nor susceptible to potency amplification by 5alpha reduction. Therefore, the effects of dihydrotestosterone may differ from those of T in older men. This study evaluated the efficacy and safety of 3 months treatment with transdermal dihydrotestosterone gel on muscle strength, mobility, and quality of life in ambulant, community-dwelling men aged 60 yr or older. Eligible men (plasma T < or =15 nmol/liter) were randomized to undergo daily dermal application of 70 mg dihydrotestosterone gel (n = 18) or vehicle (n = 19) and were studied before, monthly during, and 1 month after treatment. Among 33 (17 dihydrotestosterone, 16 placebo) men completing the study with a high degree of compliance, dihydrotestosterone had significant effects on circulating hormones (increased dihydrotestosterone; decreased total and free testosterone, LH, and FSH; unchanged SHBG and estradiol), lipid profiles (decreased total and low-density lipoprotein cholesterols; unchanged high-density lipoprotein cholesterol and triglycerides), hematopoiesis (increased hemoglobin, hematocrit, and red cell counts), and body composition (decreased skinfold thickness and fat mass; unchanged lean mass and waist to hip ratio). Muscle strength measured by isokinetic peak torque was increased in flexion of the dominant knee but not in knee extension or shoulder contraction, nor was there any significant change in gait, balance, or mobility tests, in cognitive function, or in quality of life scales. Dihydrotestosterone treatment had no adverse effects on prostate (unchanged prostate volumes and prostate-specific antigen) and cardiovascular (no adverse change in vascular reactivity or lipids) safety markers. We conclude that 3 months treatment with transdermal dihydrotestosterone gel demonstrates expected androgenic effects, short-term safety, and limited improvement in lower limb muscle strength but no change in physical functioning or cognitive function.


Subject(s)
Androgens/deficiency , Dihydrotestosterone/administration & dosage , Dihydrotestosterone/pharmacology , Gait/physiology , Muscle, Skeletal/physiology , Quality of Life/psychology , Administration, Cutaneous , Aged , Aging/metabolism , Androgens/blood , Body Height/drug effects , Dihydrotestosterone/adverse effects , Double-Blind Method , Endothelium, Vascular/drug effects , Gait/drug effects , Hormones/blood , Humans , Male , Middle Aged , Muscle, Skeletal/drug effects , Neuropsychological Tests , Patient Compliance , Prostate/diagnostic imaging , Prostate/drug effects , Ultrasonography
12.
J Appl Physiol (1985) ; 89(6): 2123-9, 2000 Dec.
Article in English | MEDLINE | ID: mdl-11090558

ABSTRACT

The goals of this study were to further our understanding of diaphragm embryogenesis and the pathogenesis of congenital diaphragmatic hernia (CDH). Past work suggests that the pleuroperitoneal fold (PPF) is the primary source of diaphragmatic musculature. Furthermore, defects associated with an animal model of CDH can be traced back to the formation of the PPF. This study was designed to elucidate the anatomic structure of the PPF and to determine which regions of the PPF malform in the well-established nitrofen model of CDH. This was achieved by producing three-dimensional renderings constructed from serial transverse sections of control and nitrofen-exposed rats at embryonic day 13.5. Renderings of left- and right-sided defects demonstrated that the malformations were always limited to the dorsolateral portions of the caudal regions of the PPF. These data provide an explanation of why the holes in diaphragmatic musculature associated with CDH are characteristically located in dorsolateral regions. Moreover, these data provide further evidence against the widely stated hypothesis that a failure of pleuroperitoneal canal closure underlies the pathogenesis of nitrofen-induced CDH.


Subject(s)
Diaphragm/embryology , Hernia, Diaphragmatic/embryology , Hernia, Diaphragmatic/pathology , Animals , Embryo, Mammalian/anatomy & histology , Embryo, Mammalian/pathology , Embryo, Mammalian/physiology , Embryonic and Fetal Development , Hernia, Diaphragmatic/chemically induced , Hernias, Diaphragmatic, Congenital , Image Processing, Computer-Assisted , Lung/embryology , Peritoneum/embryology , Phenyl Ethers , Rats , Rats, Sprague-Dawley
13.
Endocrinology ; 140(5): 2071-6, 1999 May.
Article in English | MEDLINE | ID: mdl-10218956

ABSTRACT

1Alpha,25-dihydroxyvitamin D3 [1,25-(OH)2D3] inhibits the proliferation of many cancer cells in culture, but not the aggressive human prostate cancer cell line DU 145. We postulated that the 1,25-(OH)2D3-resistant phenotype in DU 145 cells might result from the high levels of expression of 25-hydroxyvitamin D-24-hydroxylase (24-hydroxylase) induced by treatment with 1,25-(OH)2D3. As this P450 enzyme initiates 1,25-(OH)2D3 catabolism, we presumed that a high level of enzyme induction could limit the effectiveness of the 1,25-(OH)2D3 antiproliferative action. To examine this hypothesis we explored combination therapy with liarozole fumarate (R85,246), an imidazole derivative currently in trials for prostate cancer therapy. As imidizole derivatives are known to inhibit P450 enzymes, we postulated that this drug would inhibit 24-hydroxylase activity, increasing the 1,25-(OH)2D3 half-life, thereby enhancing 1,25-(OH)2D3 antiproliferative effects on DU 145 cells. Cell growth was assessed by measurement of viable cells using the MTS assay. When used alone, neither 1,25-(OH)2D3 (1-10 nM) nor liarozole (1-10 microM) inhibited DU 145 cell growth. However, when added together, 1,25-(OH)2D3 (10 nM)/liarozole (1 microM) inhibited growth 65% after 4 days of culture. We used a TLC method to assess 24-hydroxylase activity and demonstrated that liarozole (1-100 microM) inhibited this P450 enzyme in a dose-dependent manner. Moreover, liarozole treatment caused a significant increase in 1,25-(OH)2D3 half-life from 11 to 31 h. In addition, 1,25-(OH)2D3 can cause homologous up-regulation of the vitamin D receptor (VDR), and in the presence of liarozole, this effect was amplified, thus enhancing 1,25-(OH)2D3 activity. Western blot analyses demonstrated that DU 145 cells treated with 1,25-(OH)2D3/liarozole showed greater VDR up-regulation than cells treated with either drug alone. In summary, our data demonstrate that liarozole augments the ability of 1,25-(OH)2D3 to inhibit DU 145 cell growth. The mechanism appears to be due to inhibition of 24-hydroxylase activity, leading to increased 1,25-(OH)2D3 half-life and augmentation of homologous up-regulation of VDR. We raise the possibility that combination therapy using 1,25-(OH)2D3 and liarozole or other inhibitors of 24-hydroxylase, both in nontoxic doses, might serve as an effective treatment for prostate cancer.


Subject(s)
25-Hydroxyvitamin D3 1-alpha-Hydroxylase/antagonists & inhibitors , Calcitriol/pharmacology , Cell Division/drug effects , Enzyme Inhibitors/pharmacology , Imidazoles/pharmacology , Prostatic Neoplasms/pathology , Calcitriol/blood , Drug Synergism , Half-Life , Humans , Male , Receptors, Calcitriol/metabolism , Tumor Cells, Cultured
14.
Endocrinology ; 140(3): 1205-12, 1999 Mar.
Article in English | MEDLINE | ID: mdl-10067845

ABSTRACT

We have recently shown that 1alpha,25-dihydroxyvitamin D3 [1,25-(OH)2D3] inhibits proliferation of LNCaP cells, an androgen-responsive human prostate cancer cell line. Also, 1,25-(OH)2D3 increases androgen receptor (AR) abundance and enhances cellular responses to androgen in these cells. In the current study, we have investigated the mechanism by which 1,25-(OH)2D3 regulates AR gene expression and the involvement of AR in the 1,25-(OH)2D3- and 9-cis retinoic acid (RA)-mediated growth inhibition of LNCaP cells. Northern blot analyses demonstrated that the steady-state messenger RNA (mRNA) level of AR was significantly increased by 1,25-(OH)2D3 in a dose-dependent manner. Time-course experiments revealed that the increase of AR mRNA by 1,25-(OH)2D3 exhibited delayed kinetics. In response to 1,25-(OH)2D3, AR mRNA levels were first detected to rise at 8 h and reached a maximal induction of 10-fold over the untreated control at 48 h; the effect was sustained at 72 h. Furthermore, the induction of AR mRNA by 1,25-(OH)2D3 was completely abolished by incubation of cells with cycloheximide, a protein synthesis inhibitor. 1,25-(OH)2D3 was unable to induce expression of an AR promoter-luciferase reporter. Together, these findings indicate that the stimulatory effect of 1,25-(OH)2D3 on AR gene expression is indirect. Western blot analyses showed an increase of AR protein in 1,25-(OH)2D3-treated cells. This increased expression of AR was followed by 1,25-(OH)2D3-induced inhibition of growth in LNCaP cells. Similar to 1,25-(OH)2D3, 9-cis RA also induced AR mRNA expression, and the effect of both hormones was additive. Moreover, 1,25-(OH)2D3 and 9-cis RA acted synergistically to inhibit LNCaP cell growth. These antiproliferative effects of 1,25-(OH)2D3 and 9-cis RA, alone or in combination, were blocked by the pure AR antagonist, Casodex. In conclusion, our results demonstrate that growth inhibition of LNCaP cells by 1,25-(OH)2D3 and 9-cis RA is mediated by an AR-dependent mechanism and preceded by the induction of AR gene expression. This finding, that differentiating agents such as vitamin D and A derivatives are potent inducers of AR, may have clinical implications in the treatment of prostate cancer.


Subject(s)
Calcitriol/therapeutic use , Gene Expression Regulation, Neoplastic/drug effects , Prostatic Neoplasms/drug therapy , Receptors, Androgen/genetics , Tretinoin/therapeutic use , Alitretinoin , Cell Division/drug effects , Cycloheximide/pharmacology , Humans , Male , Prostatic Neoplasms/metabolism , Prostatic Neoplasms/pathology , Protein Synthesis Inhibitors/pharmacology , Tumor Cells, Cultured , Up-Regulation
15.
Endocrinology ; 138(8): 3290-8, 1997 Aug.
Article in English | MEDLINE | ID: mdl-9231780

ABSTRACT

We and others have recently shown that 1alpha,25-dihydroxyvitamin D3 [1,25-(OH)2D3] significantly inhibits cell proliferation and increases secretion of prostate-specific antigen (PSA) in LNCaP cells, an androgen-responsive human prostate cancer cell line. The present study was designed to investigate the possible interactions between 1,25-(OH)2D3 and androgens in the regulation of LNCaP cellular function. LNCaP cell growth was dose-dependently inhibited by 1,25-(OH)2D3 (60% inhibition at 10 nM) when cells were cultured in medium supplemented with FBS (FBS medium). 1,25-(OH)2D3-treated cells showed a 5-fold increase in PSA secretion, similar to the increase seen in dihydrotestosterone (DHT)-treated cells. In combination, 1,25-(OH)2D3 and DHT synergistically enhanced PSA secretion 22-fold. This synergistic effect was even greater when cells were cultured in medium supplemented with charcoal-stripped serum (CSS medium), where endogenous steroids are substantially depleted. Under these conditions, 1,25-(OH)2D3 and DHT together stimulated PSA secretion up to 50-fold over the untreated control. Radioligand binding assays and Western blot analyses showed that the androgen receptor (AR) content was increased significantly by 1,25-(OH)2D3 at 48 h. Furthermore, the steady-state mRNA level of AR was up-regulated approximately 2-fold by 1,25-(OH)2D3 at 24 h. When cells were grown in CSS medium, 1,25-(OH)2D3 alone no longer inhibited cell growth or induced PSA secretion. Titration experiments revealed that the addition of DHT at 1 nM to the medium restored the antiproliferative activity of 1,25-(OH)2D3. Conversely, an antiandrogen, Casodex, completely blocked 1,25-(OH)2D3 antiproliferative and PSA stimulation activities when cells were cultured in FBS medium. In conclusion, these results demonstrate that the antiproliferative and PSA induction activities of 1,25-(OH)2D3 in LNCaP cells are dependent upon androgen action and that AR up-regulation by 1,25-(OH)2D3 likely contributes to the synergistic actions of 1,25-(OH)2D3 and DHT in these cells.


Subject(s)
Androgens/pharmacology , Calcitriol/pharmacology , Neoplasms, Hormone-Dependent/pathology , Prostatic Neoplasms/pathology , Analysis of Variance , Androgen Antagonists/pharmacology , Anilides/pharmacology , Blotting, Northern , Blotting, Western , Cell Division/drug effects , Dihydrotestosterone/pharmacology , Dose-Response Relationship, Drug , Drug Synergism , Humans , Male , Neoplasms, Hormone-Dependent/chemistry , Neoplasms, Hormone-Dependent/metabolism , Nitriles , Prostate-Specific Antigen/metabolism , Prostatic Neoplasms/chemistry , Prostatic Neoplasms/metabolism , Receptors, Androgen/analysis , Receptors, Androgen/drug effects , Receptors, Androgen/physiology , Tosyl Compounds , Tritium , Tumor Cells, Cultured , Up-Regulation
16.
Mol Endocrinol ; 8(2): 197-209, 1994 Feb.
Article in English | MEDLINE | ID: mdl-8170476

ABSTRACT

The Pan gene encodes at least two distinct transcripts, Pan-1 and Pan-2 (also known as E47 and E12, respectively), by the mechanism of alternative RNA splicing. Northern blot analyses performed on rat and mouse tissues have detected ubiquitously expressed Pan transcripts, but the abundance, distribution, and form of Pan proteins have not been clearly defined. Studies of cell lines representing endocrine, fibroblast, and lymphoid lineages using polyclonal antisera to detect E2A proteins have suggested that significant E2A protein expression is restricted to B-lymphocytes. We have developed a monoclonal antibody, Yae, which is specific for Pan/E2A proteins, and have used the Yae antibody to examine a variety of endocrine and nonendocrine cell lineages for differences in Pan/E2A protein expression, subcellular localization, and heteromeric complex formation. In contrast to previous results obtained using polyclonal antiseras to detect Pan/E2A proteins, we report comparable levels of Pan proteins in GH/PRL- and insulin-producing, B- and T-lymphocyte cells. IEF-1, a pancreatic beta-cell type-specific complex believed to regulate insulin expression, is demonstrated to consist of at least two distinct species, one of which does not contain Pan molecules. Although it has been postulated that pituitary endocrine cells and pancreatic endocrine beta-cells share identical Pan/E2A complexes, native-Western analyses of pituitary and endocrine beta-cells detect Pan proteins in distinct cell type-specific complexes.


Subject(s)
DNA-Binding Proteins/biosynthesis , Endocrine Glands/metabolism , Transcription Factors/biosynthesis , Animals , Antibodies, Monoclonal , Base Sequence , Blotting, Western , Cell Line , Cricetinae , DNA-Binding Proteins/physiology , Electrophoresis, Polyacrylamide Gel , Endocrine Glands/cytology , Gene Expression/physiology , Humans , Lymphocytes/metabolism , Molecular Sequence Data , Rats , TCF Transcription Factors , Transcription Factor 7-Like 1 Protein , Transcription Factors/physiology
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