Differential Expression of A-Type and B-Type Lamins during Hair Cycling

Multiple genetic disorders caused by mutations that affect the proteins lamin A and C show strong skin phenotypes. These disorders include the premature aging disorders Hutchinson-Gilford progeria syndrome and mandibuloacral dysplasia, as well as restrictive dermopathy. Prior studies have shown that the lamin A/C and B proteins are expressed in skin, but little is known about their normal expression in the different skin cell-types and during the hair cycle. Our immunohistochemical staining for lamins A/C and B in wild-type mice revealed strong expression in the basal cell layer of the epidermis, the outer root sheath, and the dermal papilla during all stages of the hair cycle. Lower expression of both lamins A/C and B was seen in suprabasal cells of the epidermis, in the hypodermis, and in the bulb of catagen follicles. In addition, we have utilized a previously described mouse model of Hutchinson-Gilford progeria syndrome and show here that the expression of progerin does not result in pronounced effects on hair cycling or the expression of lamin B.     

雄激素受体共调节因子及其在前列腺癌进展中的作用

雄激素受体（AR）信号通路在前列腺癌的发生、进展和转移中发挥着重要作用,但AR介导组织对雄激素的特异应答是通过与其相互作用的AR共调节因子共同完成的,许多AR共调节因子的功能已被广泛研究。简要综述了目前发现的部分AR共调节因子在调节AR转录活性及前列腺癌发生、进展中的生物学作用。     

核纤层蛋白与核纤层病的研究进展

核纤层蛋白(lamin)是中间纤维蛋白家族的重要成员,其多聚体组成的网格状结构紧贴于核膜内侧,在维持细胞核的正常及有丝分裂过程中发挥着重要的作用。近年来,大量研究表明编码核纤层蛋白的基因尤其是lamin A编码基因(LMNA)突变会引起一系列的疾病,即核纤层病(lami-nopathy)。该文就核纤层蛋白和核纤层病的关系进行综述,有助于读者了解核纤层蛋白的重要性,也为核纤层病的治疗提供线索。     

Predictive Clinical Indicators of Biochemical Progression in Advanced Prostate Cancer Patients Receiving Leuplin Depot as Androgen Deprivation Therapy

Therapeutic planning and counseling for advanced prostate cancer patients receiving androgen deprivation therapy (ADT) is complicated because the prognoses are highly variable. The purpose of this study is to identify predictive clinical indicators of biochemical progression (BCP). In this retrospective analysis, data from 107 newly diagnosed patients (from November 1995 to April 2008) with advanced prostate adenocarcinoma receiving Leuprorelin acetate depot were analyzed. Data was collected from the computerized registry of two collaborating medical centers in Taiwan. Cox regression and Kaplan-Meier analyses were used to evaluate the relationship between potential predictive parameters and BCP. Univariate analysis revealed that predictors of BCP included (1) initial serum prostate-specific antigen (PSA) (hazard ratio [HR], 1.00; 95% confidence interval [CI] 1.00–1.00); (2) log of initial PSA (HR, 1.35; 95% CI 1.17–1.56); (3) PSA density at diagnosis (HR, 1.00; 95% CI 1.00–1.01), and (4) pathological bone fracture (HR, 2.22; 95% CI 1.20–4.11). Age (HR, 0.94; 95% CI 0.91–0.98) and hemoglobin levels (HR, 0.86; 95% CI 0.76–0.97) were also associated with greater risk of BCP. After adjusting for age, pathologic fracture, and hemoglobin level, the initial PSA and PSA density were no longer significantly associated with BCP. However, age and hemoglobin levels continued to be associated with greater risk of BCP (P≤0.007). Using Kaplan-Meier analysis, patients with higher initial PSA concentration, pathological bone fracture, and low hemoglobin had a greater probability of BCP. Thus, low hemoglobin and age are predictive indicators of BCP and therefore early indicators of BCP despite ADT therapy.     

The Role of Androgen Receptor Mutations in Prostate Cancer Progression

Prostate tumour growth is almost always dependent upon the androgen receptor pathway and hence therapies aimed at blocking this signalling axis are useful tools in the management of this disease. Unfortunately such therapies invariably fail; and the tumour progresses to an “androgen-independent” stage. In such cases androgen receptor expression is almost always maintained and much evidence exists to suggest that it may still be driving growth. One mechanism by which the receptor is thought to remain active is mutation. This review summarises the present data on androgen receptor mutations in prostate cancer, and how such substitutions offer a growth advantage by affecting cofactor interactions or by reducing ligand specificity. Such alterations appear to have a subsequent effect upon gene expression suggesting that tumours may “behave” differently dependent upon the ligand promoting growth and if a mutation is present.     

Concentration-dependent Effects of Nuclear Lamins on Nuclear Size in Xenopus and Mammalian Cells

A fundamental question in cell biology concerns the regulation of organelle size. While nuclear size is exquisitely controlled in different cell types, inappropriate nuclear enlargement is used to diagnose and stage cancer. Clarifying the functional significance of nuclear size necessitates an understanding of the mechanisms and proteins that control nuclear size. One structural component implicated in the regulation of nuclear morphology is the nuclear lamina, a meshwork of intermediate lamin filaments that lines the inner nuclear membrane. However, there has not been a systematic investigation of how the level and type of lamin expression influences nuclear size, in part due to difficulties in precisely controlling lamin expression levels in vivo. In this study, we circumvent this limitation by studying nuclei in Xenopus laevis egg and embryo extracts, open biochemical systems that allow for precise manipulation of lamin levels by the addition of recombinant proteins. We find that nuclear growth and size are sensitive to the levels of nuclear lamins, with low and high concentrations increasing and decreasing nuclear size, respectively. Interestingly, each type of lamin that we tested (lamins B1, B2, B3, and A) similarly affected nuclear size whether added alone or in combination, suggesting that total lamin concentration, and not lamin type, is more critical to determining nuclear size. Furthermore, we show that altering lamin levels in vivo, both in Xenopus embryos and mammalian tissue culture cells, also impacts nuclear size. These results have implications for normal development and carcinogenesis where both nuclear size and lamin expression levels change.     

雄激素受体信号转导途径及其在前列腺癌发展中的作用

前列腺癌是西方男性发病率最高的癌症之一,在采用雄激素阻断疗法后,大部分患者的病情可得到控制,但经过一段时间又会转变为雄激素非依赖型前列腺癌。雄激素受体(AR)在前列腺细胞中扮演重要的角色,它可调节大量基因的表达。在前列腺癌由雄激素依赖型向雄激素非依赖型的转变过程中,AR及其信号途径通过多种方式发挥作用,AR基因的扩增、AR的突变,以及与共激活子之间作用的改变都可能使细胞获得雄激素非依赖型的生长能力。此外,AR还受到多肽生长因子和细胞因子等的调节,表现激素非依赖型的转录激活活性。AR在前列腺癌中作用的阐明对前列腺癌的诊断与治疗有着重大的意义。     

Integrating Biomedical Knowledge to Model Pathways of Prostate Cancer Progression

Due to pathologic, histologic, and biologic variation within prostate cancers, profiling the genetic changes associated with disease progression has been difficult. Although initial integration of data from profiling studies had been limited by platform variation, bioinformatic tools and analytic techniques have enabled integrative analysis of profiling studies and the identification of more robust and valid profiles. The identification of key transition points in the progression of prostate cancer relies on profiling precursor lesions and “pure” cell populations. Utilizing laser-capture microdissection to isolate 101 cell populations, a more specific genetic profile of progression from benign epithelium to metastatic disease was obtained. This laser-capture profile was analyzed in the context of the Molecular Concepts Map (MCM), a compendium of over 15,000 molecular concepts including other expression profiles of prostate cancer, to obtain an integrative molecular model of progression. The conceptual connections associated with progression confirm that prostate cancer biology is largely driven by pathways related to androgen signaling and epithelial cell biology; however, further analysis of concepts associated with progression suggests stromal factors are highly associated with progression of prostate cancer. The effect of stromal signatures on the progression model suggests the impact of stromal signature downregulation may reflect both a change in the epithelia:stroma ratio within higher grade tumors and also a microenvironment influence on prostate epithelia. Analyzing complex gene expression signatures in the context of molecular concepts improves integrative models and may improve detection, prognostication, or targeted therapy.     

Overexpression of FGF9 in Prostate Epithelial Cells Augments Reactive Stroma Formation and Promotes Prostate Cancer Progression

Bone metastasis is the major cause of morbidity and mortality of prostate cancer (PCa). Fibroblast growth factor 9 (FGF9) has been reported to promote PCa bone metastasis. However, the mechanism by which overexpression of FGF9 promotes PCa progression and metastasis is still unknown. Herein, we report that transgenic mice forced to express FGF9 in prostate epithelial cells (F9TG) developed high grade prostatic intraepithelial neoplasia (PIN) in an expression level- and time-dependent manner. Moreover, FGF9/TRAMP bigenic mice (F9TRAMP) grew advanced PCa earlier and had higher frequencies of metastasis than TRAMP littermates. We observed tumor microenvironmental changes including hypercellularity and hyperproliferation in the stromal compartment of F9TG and F9TRAMP mice. Expression of TGFβ1, a key signaling molecule overexpressed in reactive stroma, was increased in F9TG and F9TRAMP prostates. Both in vivo and in vitro data indicated that FGF9 promoted TGFβ1 expression via increasing cJun-mediated signaling. Moreover, in silico analyses showed that the expression level of FGF9 was positively associated with expression of TGFβ1 and its downstream signaling molecules in human prostate cancers. Collectively, our data demonstrated that overexpressing FGF9 in PCa cells augmented the formation of reactive stroma and promoted PCa initiation and progression.     

Opposing Roles of Dnmt1 in Early- and Late-Stage Murine Prostate Cancer

Previous studies have shown that tumor progression in the transgenic adenocarcinoma of mouse prostate (TRAMP) model is characterized by global DNA hypomethylation initiated during early-stage disease and locus-specific DNA hypermethylation occurring predominantly in late-stage disease. Here, we utilized Dnmt1 hypomorphic alleles to examine the role of Dnmt1 in normal prostate development and in prostate cancer in TRAMP. Prostate tissue morphology and differentiation status was normal in Dnmt1 hypomorphic mice, despite global DNA hypomethylation. TRAMP; Dnmt1 hypomorphic mice also displayed global DNA hypomethylation, but were characterized by altered tumor phenotype. Specifically, TRAMP; Dnmt1 hypomorphic mice exhibited slightly increased tumor incidence and significantly increased pathological progression at early ages and, conversely, displayed slightly decreased tumor incidence and significantly decreased pathological progression at advanced ages. Remarkably, hypomorphic Dnmt1 expression abrogated local and distant site macrometastases. Thus, Dnmt1 has tumor suppressor activity in early-stage prostate cancer, and oncogenic activity in late stage prostate cancer and metastasis. Consistent with the biological phenotype, epigenomic studies revealed that TRAMP; Dnmt1 hypomorphic mice show dramatically reduced CpG island and promoter DNA hypermethylation in late-stage primary tumors compared to control mice. Taken together, the data reveal a crucial role for Dnmt1 in prostate cancer and suggest that Dnmt1-targeted interventions may have utility specifically for advanced and/or metastatic prostate cancer.Changes in DNA methyltransferase (Dnmt) expression and DNA methylation are observed in human prostate cancer (3, 38, 41). Of particular interest, genes with tumor suppressive function become hypermethylated and silenced, which correlates with the development of specific disease phenotypes (2, 3, 38). Although an association between prostate cancer and alterations in DNA methylation has been established, in vivo models are required to determine whether these changes functionally contribute to the disease. In this context, studies in which pharmacological inhibitors of Dnmts were shown to inhibit prostate cancer in murine models have proven informative (34, 56). However, it remains unknown whether genetic disruption of epigenetic components, such as Dnmts, also impacts prostate cancer development. This is a critical question since the pharmacological inhibitors of Dnmts have pleiotropic effects, including those unrelated to activation of methylation-silenced genes (21, 23, 31). Moreover, no studies to date have examined whether Dnmts or DNA methylation play roles in normal prostate development; this information is vital to fully understanding the effects that inhibiting DNA methylation may have on prostate cancer.Dnmt1 is a maintenance DNA methyltransferase that propagates preexisting DNA methylation patterns in genomic DNA (44). Dnmt1 also is involved in de novo DNA methylation in cancer cells and interacts with other key epigenetic control molecules, including histone-modifying enzymes (11, 19). Murine models have been used to investigate the in vivo functions of Dnmt1. Complete genetic knockout of Dnmt1 is embryonic lethal in mice (29). However, hypomorphic expression of Dnmt1 allows murine development to proceed but causes global DNA hypomethylation and impacts cancer development and progression (7, 14, 28). Specifically, hypomorphic expression of Dnmt1 can lead to the development of lymphoma (14). Furthermore, crossing Dnmt1 hypomorphic mice with murine tumor models alters tumor progression, resulting in either increased or decreased tumor development, depending on the disease stage and tissue site (1, 7, 53). For example, reduced expression of Dnmt1 dramatically decreases intestinal polyp formation in Apc^Min/+ mice, either alone or in combination with 5-aza-2′-deoxycytidine treatment (7, 27). However, it was later noted that reduced expression of Dnmt1 has a dual effect on intestinal cancer in Apc^Min/+ mice, in which the development of early stage intestinal microadenomas is accelerated, whereas the formation of adenomatous polyps is significantly reduced (53). In addition, Apc^Min/+ Dnmt1 hypomorphic mice develop liver cancer associated with the loss of heterozygosity of Apc (53). Similarly, in Dnmt1 hypomorphic mice crossed to Mlh1^−/− mice, a dual effect was noted wherein mice developed fewer intestinal cancers but displayed increased T- and B-cell lymphomas (52). In addition, a recent study demonstrated that hypomorphic Dnmt1 expression is associated with reduced squamous cell carcinoma of the tongue and esophagus, resulting in decreased invasive cancer (1). Taken together, the data suggest that Dnmt1 has diverse effects on cancer development, which are dependent on tissue context and tumor stage.TRAMP is a well-established transgenic prostate cancer model driven by prostate-specific expression of the simian virus 40 (SV40) T/t oncogenes (16). TRAMP mice are characterized by Dnmt mRNA and protein overexpression, altered DNA methylation, and altered gene expression during prostate cancer development (2, 33, 35, 37). Of the three enzymatically active Dnmts, Dnmt1 shows the greatest level of overexpression in TRAMP, and this correlates with Rb inactivation, a key genetic event driving prostate cancer in the model (37). Most critically, global DNA hypomethylation occurs during early and late disease stages, while DNA hypermethylation occurs primarily at late disease stages in TRAMP (35).Here, we utilized Dnmt1 hypomorphic mice and the TRAMP model to assess the role of DNA methylation in both normal prostatic development and prostate cancer. The Dnmt1 hypomorphic mouse model used involves two different hypomorphic alleles (N and R), resulting in four genotypes with progressively reduced DNA methylation (Dnmt1^+/+, Dnmt1^R/+, Dnmt1^N/+, and Dnmt1^N/R) (7, 52). The N allele consists of a PGK-Neo insertion that deletes a portion of exon 4 of Dnmt1, resulting in severely reduced Dnmt1 expression, while the R allele involves a lacO insertion into intron 3 of Dnmt1, which partially reduces Dnmt1 expression (7, 52). Based on our previous work establishing the timing of DNA hypomethylation and DNA hypermethylation in TRAMP, we hypothesized that hypomorphic Dnmt1 expression in TRAMP may have tumor-promoting effects at early disease stages and tumor-inhibitory effects at later stages of prostate cancer progression. Our data are consistent with this hypothesis and, more importantly, reveal a critical and unanticipated role for Dnmt1 in prostate cancer metastasis.     

Expression of Dicer and Its Related MiRNAs in the Progression of Prostate Cancer

Dicer is aberrantly expressed in several types of malignancies. Cleaved by Dicer, the small noncoding microRNAs (miRNAs) are considered potential tools for the diagnosis and prognosis of cancer. This study investigated the expression of miRNAs thought to target Dicer. Expression of 1,205 human miRNAs and miRNA*s were examined in four patients with prostate cancer (PCa) by miRNA array in which the threshold was set as two-fold. Seventy-three miRNAs and miRNA*s were significantly down-regulated while 10 were up-regulated in PCa tissues compared with matched histologically normal glands. Of these, miR-29b-1, miR-200a, miR-370, and miR-31, which were the most down/up-regulated and closely potentially target to the Dicer 3′ UTR, were investigated further. Tissues of primary tumors and matched normal prostate glands from 185 patients with PCa were collected for further investigation. Dicer mRNA levels were negatively correlated with miR-29b-1 (ρs = −0.177, p = 0.017), miR-200a (ρs = -0.489, p < 0.0001) and miR-31 (ρs = −0.314, p < 0.0001) expression. Compared with adjacent normal glands, PCa tissues showed significantly lower miR-200a and miR-31 expression levels. Furthermore, in metastatic PCa, the expression levels of miR-200a, miR-370, and miR-31 were dramatically higher than in localized PCa. Additionally, elevated expression levels of miR-200a and miR-31 appeared to be associated with castration-resistant PCa. These findings suggest possibilities that miR-200a and miR-31 target Dicer and are involved in the carcinogenesis, migration, and behavior of castration-resistant PCa, indicating that they could be potential biomarkers for monitoring PCa progression.     

PSA密度对前列腺癌病理结果的预测价值

目的:评估前列腺特异抗原密度(prostate specific antigen density,PASD)对前列腺癌根治术后不良病理结果的预测价值.方法:回顾性分析50例病理确诊为前列腺癌患者的临床资料,收集患者术前总前列腺特异抗原(total prostate specific antigen,tPSA)、PSAD及穿刺活检Gleason评分结果,比较在手术切缘阳性(positive surgical margins,PSM)、前列腺包膜外侵犯(extracapsular prostatic extension,EPE)、精囊入侵(seminal vesicle invasion,SVI)患者中以上各项指标的差异,对有统计学差异的因素行多元Logistic回归分析,筛选影响浸润的最主要因素,同时运用工作特征曲线(ROC曲线)比较各指标的预测价值.结果:PSM,EPE和SVI患者之间PSAD存在统计学差异,PSAD曲线下面积高于PSA与Gleason评分.多元Logistic回归分析结果表明,PSAD和Gleason评分对PSM和EPE有着统计学意义的预测价值,且PSAD和PSA与SVI有关.结论:PSAD可作为接受前列腺癌根治术的患者术后不良的预测指标.     

药物代谢酶及转运体与前列腺癌药物治疗

药物代谢酶是催化体内摄入的各种药物进行生物转化的一系列重要酶,属于生物转化酶系中的一类.虽然药物生物转化的主要场所在肝脏,但在肝外组织(如前列腺)亦存在,而且可影响药物在局部的生物转化率.药物转运体在药物的跨膜转运中发挥了重要的作用,影响了药物在体内的药代动力学进程,药物转运体在组织中分布广泛;本文着重阐述这些药物代谢酶及转运体在治疗前列腺癌药物中的作用,及它们在前列腺中的特异性表达,同时讨论了在不同的治疗策略中与药物代谢酶及转运体相关的靶向作用.     

Upregulation of SATB1 Is Associated with Prostate Cancer Aggressiveness and Disease Progression

Disease aggressiveness remains a critical factor to the progression of prostate cancer. Transformation of epithelial cells to mesenchymal lineage, associated with the loss of E-cadherin, offers significant invasive potential and migration capability. Recently, Special AT-rich binding protein (SATB1) has been linked to tumor progression. SATB1 is a cell-type restricted nuclear protein, which functions as a tissue-specific organizer of DNA sequences during cellular differentiation. Our results demonstrate that SATB1 plays significant role in prostate tumor invasion and migration and its nuclear localization correlates with disease aggressiveness. Clinical specimen analysis showed that SATB1 was predominantly expressed in the nucleus of high-grade tumors compared to low-grade tumor and benign tissue. A progressive increase in the nuclear levels of SATB1 was observed in cancer tissues compared to benign specimens. Similarly, SATB1 protein levels were higher in a number of prostate cancer cells viz. HPV-CA-10, DU145, DUPro, PC-3, PC-3M, LNCaP and C4-2B, compared to non-tumorigenic PZ-HPV-7 cells. Nuclear expression of SATB1 was higher in biologically aggressive subclones of prostate cancer cells with their respective parental cell lines. Furthermore, ectopic SATB1 transfection conferred increased cell motility and invasiveness in immortalized human prostate epithelial PZ-HPV-7 cells which correlated with the loss of E-cadherin expression. Consequently, knockdown of SATB1 in highly aggressive human prostate cancer PC-3M cells inhibited invasiveness and tumor growth in vivo along with increase in E-cadherin protein expression. Our findings demonstrate that SATB1 has ability to promote prostate cancer aggressiveness through epithelial-mesenchymal transition.     

Expression and Functional Role of Orphan Receptor GPR158 in Prostate Cancer Growth and Progression

Prostate cancer (PCa) is the second-leading cause of cancer-related mortality, after lung cancer, in men from developed countries. In its early stages, primary tumor growth is dependent on androgens, thus generally can be controlled by androgen deprivation therapy (ADT). Eventually however, the disease progresses to castration-resistant prostate cancer (CRPC), a lethal form in need of more effective treatments. G-protein coupled receptors (GPCRs) comprise a large clan of cell surface proteins that have been implicated as therapeutic targets in PCa growth and progression. The findings reported here provide intriguing evidence of a role for the newly characterized glutamate family member GPR158 in PCa growth and progression. We found that GPR158 promotes PCa cell proliferation independent of androgen receptor (AR) functionality and that this requires its localization in the nucleus of the cell. This suggests that GPR158 acts by mechanisms different from other GPCRs. GPR158 expression is stimulated by androgens and GPR158 stimulates AR expression, implying a potential to sensitize tumors to low androgen conditions during ADT via a positive feedback loop. Further, we found GPR158 expression correlates with a neuroendocrine (NE) differentiation phenotype and promotes anchorage-independent colony formation implying a role for GPR158 in therapeutic progression and tumor formation. GPR158 expression was increased at the invading front of prostate tumors that formed in the genetically defined conditional Pten knockout mouse model, and co-localized with elevated AR expression in the cell nucleus. Kaplan-Meier analysis on a dataset from the Memorial Sloan Kettering cancer genome portal showed that increased GPR158 expression in tumors is associated with lower disease-free survival. Our findings strongly suggest that pharmaceuticals targeting GPR158 activities could represent a novel and innovative approach to the prevention and management of CRPC.