RESUMO
Molecular understanding of how prostate cancers evade hormone therapy greatly increased over the last several years, and the realization that de novo steroidogenesis plays a significant role in tumor progression and therapeutic bypass has led to development of promising new therapeutics. In the April 2013 issue of Endocrine-Related Cancer, Lubik et al. revealed a new molecular pathway by which the IGF2 can ignite the de novo steroidogenesis engine and promote molecular events associated with tumor progression.
Assuntos
Fator de Crescimento Insulin-Like II/farmacologia , Neoplasias da Próstata/metabolismo , Esteroides/biossíntese , Humanos , MasculinoRESUMO
PURPOSE: BAF57, a component of the switching-defective and sucrose nonfermenting (SWI/SNF) chromatin-remodeling complex conglomerate, modulates androgen receptor activity to promote prostate cancer. However, the molecular consequences of tumor-associated BAF57 expression have remained undefined in advanced disease such as castration-resistant prostate cancer and/or metastasis. EXPERIMENTAL DESIGN: Clinical human specimens of primary and metastatic prostate cancer were immunohistochemically examined for tumor-grade association of BAF57 expression. Global gene expression analyses were conducted in models mimicking tumor-associated BAF57 expression. Aberrant BAF57-dependent gene expression changes, bypass of androgen-mediated signaling, and chromatin-specific SWI/SNF complex alterations with respect to cytoskeletal remodelers such as integrins were validated. Cell migration assays were used to profile the biologic phenotypes conferred under conditions simulating tumor-derived BAF57 expression. RESULTS: Immunohistochemical quantitation of primary human specimens revealed that BAF57 was significantly and aberrantly elevated as a function of tumor grade. Critically, gene expression analyses showed that BAF57 deregulation circumvented androgen-mediated signaling, elicited α2 integrin upregulation, and altered other SWI/SNF complex components at the α2 integrin locus. BAF57-dependent α2 integrin induction conferred a prometastatic migratory advantage, which was attenuated by anti-α2 integrin antibody blockade. Furthermore, BAF57 was found to be markedly upregulated in human prostate cancer metastases of the lung, lymph node, and dura. CONCLUSION: The findings herein, identifying tumor-associated BAF57 perturbation as a means to bypass androgen-signaling events that facilitate novel prometastatic phenotypes, link BAF57 upregulation to tumor dissemination. These data thereby establish BAF57 as a putative marker of metastatic potential that could be leveraged for therapeutic intervention.
Assuntos
Proteínas Cromossômicas não Histona/genética , Proteínas de Ligação a DNA/genética , Perfilação da Expressão Gênica , Regulação Neoplásica da Expressão Gênica , Neoplasias da Próstata/genética , Linhagem Celular Tumoral , Movimento Celular/genética , Proteínas Cromossômicas não Histona/metabolismo , Proteínas de Ligação a DNA/metabolismo , Humanos , Immunoblotting , Imuno-Histoquímica , Integrina alfa2/genética , Integrina alfa2/metabolismo , Masculino , Metástase Neoplásica , Análise de Sequência com Séries de Oligonucleotídeos , Fenótipo , Neoplasias da Próstata/metabolismo , Neoplasias da Próstata/patologia , Receptores Androgênicos/genética , Receptores Androgênicos/metabolismo , Transdução de Sinais/genéticaRESUMO
D-type cyclins regulate cellular outcomes in part through cyclin-dependent, kinase-independent mechanisms that modify transcription factor action, and recent in vivo studies showed that cyclin D1 associates with a large number of transcriptional regulators in cells of the retina and breast. Given the frequency of cyclin D1 alterations in cancer, it is imperative to delineate the molecular mechanisms by which cyclin D1 controls key transcription factor networks in human disease. Prostate cancer was used as a paradigm because this tumor type is reliant at all stages of the disease on androgen receptor (AR) signaling, and cyclin D1 has been shown to negatively modulate AR-dependent expression of prostate-specific antigen (KLK3/PSA). Strategies were employed to control cyclin D1 expression under conditions of hormone depletion, and the effect of cyclin D1 on subsequent androgen-dependent gene expression was determined using unbiased gene expression profiling. Modulating cyclin D1 conferred widespread effects on androgen signaling and revealed cyclin D1 to be a selective effector of hormone action. A subset of androgen-induced target genes, known to be directly regulated by AR, was strongly suppressed by cyclin D1. Analyses of AR occupancy at target gene regulatory loci of clinical relevance demonstrated that cyclin D1 limits AR residence after hormone stimulation. Together, these findings reveal a new function for cyclin D1 in controlling hormone-dependent transcriptional outcomes and demonstrate a pervasive role for cyclin D1 in regulating transcription factor dynamics.
Assuntos
Androgênios/metabolismo , Ciclina D1/metabolismo , Regulação Neoplásica da Expressão Gênica , Neoplasias da Próstata/metabolismo , Receptores Androgênicos/metabolismo , Transdução de Sinais , Linhagem Celular Tumoral , Ciclina D1/genética , Loci Gênicos/genética , Humanos , Calicreínas/biossíntese , Calicreínas/genética , Masculino , Antígeno Prostático Específico/biossíntese , Antígeno Prostático Específico/genética , Neoplasias da Próstata/genética , Receptores Androgênicos/genéticaRESUMO
Retinoblastoma (RB; encoded by RB1) is a tumor suppressor that is frequently disrupted in tumorigenesis and acts in multiple cell types to suppress cell cycle progression. The role of RB in tumor progression, however, is poorly defined. Here, we have identified a critical role for RB in protecting against tumor progression through regulation of targets distinct from cell cycle control. In analyses of human prostate cancer samples, RB loss was infrequently observed in primary disease and was predominantly associated with transition to the incurable, castration-resistant state. Further analyses revealed that loss of the RB1 locus may be a major mechanism of RB disruption and that loss of RB function was associated with poor clinical outcome. Modeling of RB dysfunction in vitro and in vivo revealed that RB controlled nuclear receptor networks critical for tumor progression and that it did so via E2F transcription factor 1-mediated regulation of androgen receptor (AR) expression and output. Through this pathway, RB depletion induced unchecked AR activity that underpinned therapeutic bypass and tumor progression. In agreement with these findings, disruption of the RB/E2F/nuclear receptor axis was frequently observed in the transition to therapy resistance in human disease. Together, these data reveal what we believe to be a new paradigm for RB function in controlling prostate tumor progression and lethal tumor phenotypes.
Assuntos
Genes do Retinoblastoma , Neoplasias da Próstata/genética , Neoplasias da Próstata/fisiopatologia , Receptores Androgênicos/fisiologia , Animais , Sequência de Bases , Linhagem Celular Tumoral , Progressão da Doença , Fator de Transcrição E2F1/fisiologia , Humanos , Masculino , Camundongos , Camundongos Nus , Modelos Biológicos , Orquiectomia , Neoplasias da Próstata/patologia , Neoplasias da Próstata/cirurgia , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , RNA Neoplásico/genética , RNA Neoplásico/metabolismo , Receptores Androgênicos/genética , Transdução de Sinais/genética , Transdução de Sinais/fisiologia , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
The cyclin D1b oncogene arises from alternative splicing of the CCND1 transcript, and harbors markedly enhanced oncogenic functions not shared by full-length cyclin D1 (cyclin D1a). Recent studies showed that cyclin D1b is selectively induced in a subset of tissues as a function of tumorigenesis; however, the underlying mechanism(s) that control tumor-specific cyclin D1b induction remain unsolved. Here, we identify the RNA-binding protein ASF/SF2 as a critical, allele-specific, disease-relevant effector of cyclin D1b production. Initially, it was observed that SF2 associates with cyclin D1b mRNA (transcript-b) in minigene analyses and with endogenous transcript in prostate cancer (PCa) cells. SF2 association was altered by the CCND1 G/A870 polymorphism, which resides in the splice donor site controlling transcript-b production. This finding was significant, as the A870 allele promotes cyclin D1b in benign prostate tissue, but in primary PCa, cyclin D1b production is independent of A870 status. Data herein provide a basis for this disparity, as tumor-associated induction of SF2 predominantly results in binding to and accumulation of G870-derived transcript-b. Finally, the relevance of SF2 function was established, as SF2 strongly correlated with cyclin D1b (but not cyclin D1a) in human PCa. Together, these studies identify a novel mechanism by which cyclin D1b is induced in cancer, and reveal significant evidence of a factor that cooperates with a risk-associated polymorphism to alter cyclin D1 isoform production. Identification of SF2 as a disease-relevant effector of cyclin D1b provides a basis for future studies designed to suppress the oncogenic alternative splicing event.
Assuntos
Processamento Alternativo/genética , Ciclina D1/genética , Regulação Neoplásica da Expressão Gênica , Neoplasias Hormônio-Dependentes/genética , Proteínas Nucleares/fisiologia , Polimorfismo Genético/genética , Neoplasias da Próstata/genética , Alelos , Biomarcadores Tumorais/genética , Western Blotting , Linhagem Celular Tumoral , Ciclina D1/metabolismo , Progressão da Doença , Perfilação da Expressão Gênica , Humanos , Técnicas Imunoenzimáticas , Imunoprecipitação , Masculino , Neoplasias Hormônio-Dependentes/metabolismo , Neoplasias Hormônio-Dependentes/patologia , Análise de Sequência com Séries de Oligonucleotídeos , Próstata/metabolismo , Próstata/patologia , Neoplasias da Próstata/metabolismo , Neoplasias da Próstata/patologia , Isoformas de Proteínas , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Proteínas de Ligação a RNA , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Fatores de Processamento de Serina-ArgininaRESUMO
PURPOSE: Alternative CCND1 splicing results in cyclin D1b, which has specialized, protumorigenic functions in prostate not shared by the cyclin D1a (full length) isoform. Here, the frequency, tumor relevance, and mechanisms controlling cyclin D1b were challenged. EXPERIMENTAL DESIGN: First, relative expression of both cyclin D1 isoforms was determined in prostate adenocarcinomas. Second, relevance of the androgen axis was determined. Third, minigenes were created to interrogate the role of the G/A870 polymorphism (within the splice site), and findings were validated in primary tissue. Fourth, the effect of G/A870 on cancer risk was assessed in two large case-control studies. RESULTS: Cyclin D1b is induced in tumors, and a significant subset expressed this isoform in the absence of detectable cyclin D1a. Accordingly, the isoforms showed noncorrelated expression patterns, and hormone status did not alter splicing. Whereas G/A870 was not independently predictive of cancer risk, A870 predisposed for transcript-b production in cells and in normal prostate. The influence of A870 on overall transcript-b levels was relieved in tumors, indicating that aberrations in tumorigenesis likely alter the influence of the polymorphism. CONCLUSIONS: These studies reveal that cyclin D1b is specifically elevated in prostate tumorigenesis. Cyclin D1b expression patterns are distinct from that observed with cyclin D1a. The A870 allele predisposes for transcript-b production in a context-specific manner. Although A870 does not independently predict cancer risk, tumor cells can bypass the influence of the polymorphism. These findings have major implications for the analyses of D-cyclin function in the prostate and provide the foundation for future studies directed at identifying potential modifiers of the G/A870 polymorphism.
Assuntos
Processamento Alternativo/genética , Ciclina D1/genética , Regulação Neoplásica da Expressão Gênica , Neoplasias da Próstata/genética , Alelos , Estudos de Casos e Controles , Ciclina D1/metabolismo , Genótipo , Humanos , Masculino , Polimorfismo Genético , Neoplasias da Próstata/patologia , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , Análise Serial de TecidosRESUMO
Factors that drive prostate cancer progression remain poorly defined, thus hindering the development of new therapeutic strategies. Disseminated tumors are treated through regimens that ablate androgen signaling, as prostate cancer cells require androgen for growth and survival. However, recurrent, incurable tumors that have bypassed the androgen requirement ultimately arise. This study reveals that the Brm ATPase, a component of selected SWI/SNF complexes, has significant antiproliferative functions in the prostate that protect against these transitions. First, we show that targeted ablation of Brm is causative for the development of prostatic hyperplasia in mice. Second, in vivo challenge revealed that Brm-/- epithelia acquire the capacity for lobe-specific, castration-resistant cellular proliferation. Third, investigation of human specimens revealed that Brm mRNA and protein levels are attenuated in prostate cancer. Fourth, Brm down-regulation was associated with an increased proliferative index, consistent with the mouse model. Lastly, gene expression profiling showed that Brm loss alters factors upstream of E2F1; this was confirmed in murine models, wherein Brm loss induced E2F1 deregulation in a tissue-specific manner. Combined, these data identify Brm as a major effector of serum androgen-induced proliferation in the prostate that is disrupted in human disease, and indicate that loss of Brm confers a proliferative advantage in prostate cancer.
Assuntos
Adenosina Trifosfatases/metabolismo , Neoplasias da Próstata/enzimologia , Neoplasias da Próstata/patologia , Fatores de Transcrição/metabolismo , Animais , Processos de Crescimento Celular/fisiologia , Fator de Transcrição E2F1/metabolismo , Humanos , Masculino , Camundongos , Hiperplasia Prostática/enzimologia , Hiperplasia Prostática/patologia , Receptores Androgênicos/metabolismoRESUMO
The androgen receptor (AR) is critical for disseminated prostate cancer proliferation and survival. AR activity is targeted either through prevention of ligand synthesis or through the use of antagonists that bind the COOH-terminal ligand-binding domain. Although initially effective, treatment fails due to restored AR activity in the presence of therapeutics. Thus, new means must be developed to target AR activity. The SWI/SNF chromatin remodeling complex is critical for AR transcriptional activity, and the BAF57 SWI/SNF subunit facilitates direct interaction with the receptor. Although selected SWI/SNF subunit expression is reduced in prostate cancer, we show that BAF57 is retained in human disease and is elevated in a subset of tumors. Functional analyses showed that BAF57 contributes uniquely to androgen-mediated stimulation of transcription without compromising the effectiveness of AR antagonists. Subsequent studies revealed that BAF57 is recruited to the AR DNA-binding domain/hinge region, which occurs concomitant with receptor activation. These data provided the basis for a novel inhibitor derived from BAF57 [BAF57 inhibitory peptide (BIPep)], which blocked AR residence on chromatin and resultant AR-dependent gene activation. Importantly, BIPep expression was sufficient to inhibit androgen-dependent prostate cancer cell proliferation in AR-positive cells. In summary, these data identify blockade of AR-BAF57 interaction as a novel means to target agonist-induced AR function in prostate cancer, and provide the first evidence that abrogation of SWI/SNF function can be developed as a point of therapeutic intervention in prostate cancer.
Assuntos
Proliferação de Células , Proteínas Cromossômicas não Histona/metabolismo , Proteínas de Ligação a DNA/metabolismo , Fragmentos de Peptídeos/farmacologia , Neoplasias da Próstata/metabolismo , Receptores Androgênicos/metabolismo , Adenocarcinoma/genética , Adenocarcinoma/metabolismo , Adenocarcinoma/patologia , Antagonistas de Receptores de Andrógenos , Animais , Cromatina/metabolismo , Imunoprecipitação da Cromatina , Proteínas Cromossômicas não Histona/antagonistas & inibidores , Proteínas Cromossômicas não Histona/genética , Proteínas de Ligação a DNA/antagonistas & inibidores , Proteínas de Ligação a DNA/genética , Humanos , Imunização , Immunoblotting , Técnicas Imunoenzimáticas , Masculino , Fragmentos de Peptídeos/imunologia , Regiões Promotoras Genéticas/genética , Neoplasias da Próstata/genética , Neoplasias da Próstata/patologia , Subunidades Proteicas , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Coelhos , Receptores Androgênicos/genética , Elementos de Resposta , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Transcrição Gênica , Ativação TranscricionalRESUMO
BACKGROUND: Prostatic adenocarcinomas are dependent on androgen receptor (AR) activity for growth and progression, and therapy for disseminated disease depends on ablation of AR activity. Recurrent tumors ultimately arise wherein AR has been re-activated. One mechanism of AR restoration is via somatic mutation, wherein cells containing mutant receptors become susceptible to activation by alternative ligands, including bisphenol A (BPA). In tumors with specific AR mutations, BPA promotes therapeutic bypass, suggesting significant negative impact to the clinical management of prostate cancer. OBJECTIVE: Our goal was to determine the mechanism of BPA action in cancer cells carrying BPA-responsive AR mutants. METHODS: The molecular signature of BPA activity in prostate cancer cells harboring mutant AR was delineated via genetic microarray analysis. Specificity of BPA action was assessed by comparison with the molecular signature elicited by dihydrotestosterone (DHT). RESULTS: BPA and DHT elicited distinct transcriptional signatures in prostate cancer cells expressing the BPA-responsive mutant AR-T877A. BPA dramatically attenuated estrogen receptor beta (ERbeta) expression; this finding was specific to prostate tumor cells in which BPA induces cellular proliferation. CONCLUSIONS: BPA induces a distinct gene expression signature in prostate cancer cells expressing somatic AR mutation, and a major molecular consequence of BPA action is down-regulation of ERbeta. Since ERbeta functions to antagonize AR function and AR-dependent proliferation, these findings reveal a novel mechanism by which BPA likely regulates cellular proliferation. Future investigation directed at dissecting the importance of ERbeta in the proliferative response to BPA will establish the contribution of this event to adverse effects associated with human exposure.
Assuntos
Adenocarcinoma/metabolismo , Receptor beta de Estrogênio/metabolismo , Estrogênios não Esteroides/farmacologia , Perfilação da Expressão Gênica , Mutação , Fenóis/farmacologia , Neoplasias da Próstata/metabolismo , Receptores Androgênicos/genética , Adenocarcinoma/genética , Compostos Benzidrílicos , Linhagem Celular Tumoral , Di-Hidrotestosterona/farmacologia , Regulação para Baixo , Receptor beta de Estrogênio/genética , Regulação Neoplásica da Expressão Gênica , Humanos , Masculino , Análise de Sequência com Séries de Oligonucleotídeos , Neoplasias da Próstata/genética , Receptores Androgênicos/metabolismoRESUMO
The retinoblastoma tumor suppressor protein (RB), a critical mediator of cell cycle progression, is functionally inactivated in the majority of human cancers, including prostatic adenocarcinoma. The importance of RB tumor suppressor function in this disease is evident because 25% to 50% of prostatic adenocarcinomas harbor aberrations in RB pathway. However, no previous studies challenged the consequence of RB inactivation on tumor cell proliferation or therapeutic response. Here, we show that RB depletion facilitates deregulation of specific E2F target genes, but does not confer a significant proliferative advantage in the presence of androgen. However, RB-deficient cells failed to elicit a cytostatic response (compared with RB proficient isogenic controls) when challenged with androgen ablation, AR antagonist, or combined androgen blockade. These data indicate that RB deficiency can facilitate bypass of first-line hormonal therapies used to treat prostate cancer. Given the established effect of RB on DNA damage checkpoints, these studies were then extended to determine the impact of RB depletion on the response to cytotoxic agents used to treat advanced disease. In this context, RB-deficient prostate cancer cells showed enhanced susceptibility to cell death induced by only a selected subset of cytotoxic agents (antimicrotubule agents and a topoisomerase inhibitor). Combined, these data indicate that RB depletion dramatically alters the cellular response to therapeutic intervention in prostate cancer cells and suggest that RB status could potentially be developed as a marker for effectively directing therapy.
Assuntos
Regulação Neoplásica da Expressão Gênica , Genes Supressores de Tumor , Neoplasias da Próstata/metabolismo , Proteína do Retinoblastoma/fisiologia , Androgênios/metabolismo , Bromodesoxiuridina/farmacologia , Ciclo Celular , Linhagem Celular Tumoral , Proliferação de Células , Sobrevivência Celular , Humanos , Masculino , Receptores Androgênicos/metabolismo , Proteína do Retinoblastoma/metabolismo , Fatores de Tempo , TransfecçãoRESUMO
Prostatic adenocarcinomas are dependent on androgen receptor (AR) signaling for growth and progression, in part through the ability of AR to induce G1-S phase cell cycle transition. Hormonal therapies that inhibit AR activity are the first line of intervention for disseminated disease, and are initially quite effective; however, recurrent, incurable tumors ultimately arise with restored AR function. Given the importance of AR in governing the potentiation of this tumor type, there has been a dedicated interest in dissecting the mechanisms by which AR promotes prostate cancer proliferation and survival. Recent studies have challenged the utility of manipulating AR activity to enhance cell death in combination with genotoxic insult. Herein, the role of AR in controlling cell cycle progression and paradoxical roles of AR in survival signals are considered, as are the potential implications of these findings for chemotherapeutic response. Although there is much to be resolved, the present data suggest that knowledge of AR action in promoting cellular proliferation can be utilized for the design of coordinate strategies that maximize cell death in response to cytotoxic chemotherapeutics.
Assuntos
Adenocarcinoma/metabolismo , Androgênios , Antineoplásicos/farmacologia , Proteínas de Neoplasias/fisiologia , Neoplasias Hormônio-Dependentes/metabolismo , Neoplasias da Próstata/metabolismo , Receptores Androgênicos/fisiologia , Adenocarcinoma/tratamento farmacológico , Adenocarcinoma/patologia , Antagonistas de Androgênios/farmacologia , Antagonistas de Androgênios/uso terapêutico , Antagonistas de Receptores de Andrógenos , Animais , Antineoplásicos/uso terapêutico , Antineoplásicos Hormonais/farmacologia , Antineoplásicos Hormonais/uso terapêutico , Antineoplásicos Fitogênicos/farmacologia , Antineoplásicos Fitogênicos/uso terapêutico , Apoptose/efeitos dos fármacos , Apoptose/fisiologia , Proteínas Reguladoras de Apoptose/metabolismo , Proteínas de Ciclo Celular/metabolismo , Divisão Celular/efeitos dos fármacos , Linhagem Celular Tumoral/efeitos dos fármacos , Linhagem Celular Tumoral/metabolismo , Desenho de Fármacos , Fase G1/efeitos dos fármacos , Fase G1/fisiologia , Regulação Neoplásica da Expressão Gênica/fisiologia , Humanos , Masculino , Microtúbulos/efeitos dos fármacos , Moduladores de Mitose/farmacologia , Moduladores de Mitose/uso terapêutico , Modelos Biológicos , Proteínas de Neoplasias/antagonistas & inibidores , Neoplasias Hormônio-Dependentes/tratamento farmacológico , Neoplasias Hormônio-Dependentes/patologia , Neoplasias da Próstata/tratamento farmacológico , Neoplasias da Próstata/patologia , Fase S/efeitos dos fármacos , Fase S/fisiologia , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
Prostatic adenocarcinomas depend on androgen for growth and survival. First line treatment of disseminated disease exploits this dependence by specifically targeting androgen receptor function. Clinical evidence has shown that androgen receptor is reactivated in recurrent tumors despite the continuance of androgen deprivation therapy. Several factors have been shown to restore androgen receptor activity under these conditions, including somatic mutation of the androgen receptor ligand-binding domain. We have shown previously that select tumor-derived mutants of the androgen receptor are receptive to activation by bisphenol A (BPA), an endocrine-disrupting compound that is leached from polycarbonate plastics and epoxy resins into the human food supply. Moreover, we have shown that BPA can promote cell cycle progression in cultured prostate cancer cells under conditions of androgen deprivation. Here, we challenged the effect of BPA on the therapeutic response in a xenograft model system of prostate cancer containing the endogenous BPA-responsive AR-T877A mutant protein. We show that after androgen deprivation, BPA enhanced both cellular proliferation rates and tumor growth. These effects were mediated, at least in part, through androgen receptor activity, as prostate-specific antigen levels rose with accelerated kinetics in BPA-exposed animals. Thus, at levels relevant to human exposure, BPA can modulate tumor cell growth and advance biochemical recurrence in tumors expressing the AR-T877A mutation.
Assuntos
Adenocarcinoma/tratamento farmacológico , Antagonistas de Receptores de Andrógenos , Fenóis/farmacologia , Neoplasias da Próstata/tratamento farmacológico , Adenocarcinoma/patologia , Androgênios/metabolismo , Animais , Compostos Benzidrílicos , Processos de Crescimento Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Relação Dose-Resposta a Droga , Humanos , Masculino , Camundongos , Camundongos Nus , Neoplasias da Próstata/patologia , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
Adipose tissue is an integral component within the endocrine system. Adipocytes produce numerous bioactive substances, and their dysregulation has serious pathophysiological consequences. We previously reported that human adipose tissue from several depots produces significant amounts of prolactin (PRL). To study locally produced PRL, we sought an acceptable in vitro model. Consequently, we developed an adipocyte cell line derived from a metastatic liposarcoma. The cell line, designated LS14, has been in continuous culture for 2 yr. These cells exhibit many properties of primary preadipocytes, including the ability to undergo terminal differentiation, as judged by morphological alterations, lipid accumulation, and increase in glycerol-3-phosphate dehydrogenase. LS14 cells express many adipose-associated genes, such as adipocyte fatty acid-binding protein (aP(2)), hormone-sensitive lipase, lipoprotein lipase, preadipocyte factor 1, adiponectin, leptin, and IL-6. Similar to primary adipocytes, LS14 cells also produce and respond to PRL, thus making them an attractive model to study adipose PRL production and function. The expression of PRL was confirmed at the transcriptional level by RT-PCR, and PRL secretion was determined by the Nb2 bioassay. Addition of exogenous PRL to LS14 cells resulted in a dose-dependent inhibition of IL-6 release. In summary, we have established a novel human adipocyte cell line with many characteristics of primary adipocytes. The LS14 cells open up new avenues for research on human adipocyte biology and add to the repertoire of nonpituitary, PRL-producing cell lines.