Establishment and characterization of androgen-independent human prostate cancer LNCaP cell model

BACKGROUND: The acquisition of an androgen-independent phenotype is the most serious issue of prostate cancer treatment. Although several experimental cell models have been reported for studying androgen independence, they have limited applications related to hormone-refractory prostate cancer. To investigate the molecular mechanism of androgen-independent growth of prostate cancer, we established a useful LNCaP cell model that resembles the clinical scenario of hormone-refractory prostate cancer. METHODS: Androgen-sensitive LNCaP parental cells were continuously maintained in a regular cell-culture medium, that is, phenol red-positive RPMI 1640 medium supplemented with 5% fetal bovine serum and 1% glutamine. Upon passage, the androgen responsiveness of those cells decreased, to a level lower than that of parental cells. We examined the growth properties and androgen responsiveness of these different LNCaP cells in vitro and in vivo. Cytogenetic characteristics and expression of androgen receptors (ARs) and prostate-specific antigen (PSA) were determined. RESULTS: Upon continuous passage, the biological behavior of parental C-33 cells (passage number less than 33) was altered. C-81 cells (passage number higher than 81) clearly exhibited more aggressive growth and lower androgen responsiveness than C-33 and C-51 cells (passage number between 35 and 80) in vitro and in vivo. Nevertheless, all these cells expressed a similar level of functional AR protein as well as a similar genetic profile. Moreover, in a steroid-reduced culture condition, C-81 cells secreted a higher level of PSA than C-33 cells. CONCLUSIONS: Our LNCaP cell model closely recapitulates the progression of human prostate cancer from the androgen-responsive to the hormone-refractory state under the androgen nondeprived condition. This cell model may provide the opportunity to understand the molecular mechanisms associated with the acquisition of androgen independence during human prostate cancer progression.     

Interleukin-4 stimulates androgen-independent growth in LNCaP human prostate cancer cells

BACKGROUND: Clinical data showed that the levels of interleukin-4 (IL-4) are significantly elevated in serum of patients with ablation resistant prostate cancer. Previous studies demonstrated that IL-4 enhances androgen receptor (AR) activation mediated by NF-kappaB in the absence or in the very low levels of androgen in prostate cancer cells. In this study, the role of IL-4 in promoting the growth of androgen-independent prostate cancer cells was examined. METHODS: LNCaP cells were transfected with a full-length IL-4 cDNA and stable clones expressing IL-4 were selected. The growth of LNCaP cells expressing IL-4 was analyzed in vitro and in vivo both in the presence and absence of androgen. RESULTS: Overexpression of IL-4 enhances the growth of androgen-sensitive LNCaP cells in culture media containing charcoal-stripped FBS condition (CS-FBC), and increases the sensitivity of LNCaP cells in response to androgen stimulation. The DHT-mediated cell growth could not be blocked by bicalutamide in IL-4 overexpressing LNCaP cells, but can be neutralized by bicalutamide in parental LNCaP and neo control cells. Furthermore, overexpression of IL-4 stimulates tumor growth of androgen-sensitive LNCaP cells both in intact and castrated male mice. CONCLUSIONS: Overexpression of IL-4 increases the sensitivity of androgen-sensitive LNCaP prostate cancer cells in response to androgen stimulation and enhances the growth of LNCaP cells both in the presence and absence of androgen in vitro and in vivo. These studies suggest that IL-4 plays an important role in promoting androgen-independent prostate cancer growth.     

Murine androgen-independent neuroendocrine carcinoma promotes metastasis of human prostate cancer cell line LNCaP

BACKGROUND: Although neuroendocrine (NE) cells in prostate cancer have been speculated to accelerate the growth and progression of surrounding cancer cells, the evidence is as yet inconclusive. We investigated the effect of an NE allograft (NE-10) and its cell line, NE-CS, which were established from the prostate of the LPB-Tag 12T-10 transgenic mouse, on human prostate cancer cell line LNCaP. METHODS: The proliferation and pulmonary metastasis of LNCaP xenografts in athymic mice with and without NE-10 allografts were evaluated. Boyden chamber assay and microarray analysis were performed to investigate changes in invasion/migration and mRNA of LNCaP cells under the influence of the NE cells, respectively. RESULTS: NE-10 did not influence the proliferation of LNCaP. The pulmonary metastasis of LNCaP with NE-10 significantly increased compared to mice without it. The NE-CS cells accelerated the in vitro invasion/migration of adenocarcinoma cells. Increased expression of mRNA of gelsolin was observed in LNCaP cells incubated with the supernatant of NE-CS cells. CONCLUSIONS: The NE-10 allograft promotes pulmonary metastasis of subcutaneously inoculated LNCaP cells by facilitating cell invasion. Secretions from NE cells upregulate the expression of gelsolin, which is an actin-binding protein, resulting in acceleration of the migration of LNCaP cells.     

LNCaP衍生的雄激素非依赖型前列腺癌细胞系C4-2对辐射的应答反应

放射治疗是治疗局灶性前列腺癌相对有效的方法,然而,30％的病人会产生辐射治疗抵抗。放射协同雄激素撤除为临床提供了一种改善疗效的治疗方法。雄激素撤除诱导的信号通路相应地也会介导前列腺癌细胞的放射敏感。C4—2细胞是由雄激素非依赖的LNCaP母体细胞在雄激素撤除条件下衍生而来的,C4-2细胞获得了雄激素非依赖生长的特性。我们分析了LNCaP和WC4－2对辐射的应答反应,克隆形成、细胞存活和细胞周期分析结果显示,C4－2细胞经照射后较LNCaP细胞更容易存活,对辐射处理表现出更强的抵抗能力。基因表达分析表明,一整套与细胞周期阻滞和DNA损伤相关的基因经过辐射处理后在LNCaP和C4．2细胞中差异表达,其结果与C4—2细胞的辐射抵抗性质一致,这些结果明显提示,前列腺癌细胞对辐射的抵抗与向雄激素非依赖发展的过程可能同步进行。LNCaP和C4-2细胞模型不仅可应用于研究前列腺癌向雄激素非依赖发展的过程,而且也用于分析前列腺癌细胞的辐射抵抗机制。     

Treatment of androgen-independent prostate cancer with dexamethasone: A prospective study in stage D2 patients

PURPOSE: In order to evaluate the efficacy of dexamethasone in the treatment of Japanese men with androgen-independent prostate cancer, a prospective study was conducted using prostate-specific antigen (PSA) as a primary end-point. METHODS: Nineteen Japanese men with stage D2 androgen-independent prostate cancer were registered and treatment was started. After ruling out anti-androgen withdrawal syndrome, they were treated with dexamethasone (1.5 mg daily). Patients were monitored for PSA, symptoms, radiologic response, survival rate, time to disease progression, time to treatment failure and complications. RESULTS: Prostate-specific antigen levels decreased in nine patients (50.0%); five (27.8%) showed a 50% or greater decrease and two (11.1%) showed an 80% or greater decrease. For the nine patients, the mean duration of PSA response was 7.3 months and the median duration was 2.1 months (range, 1.2-27.5+). Bone pain, which was noted in 13 patients at study entry, improved in seven patients (53.8%). Of nine patients who had serial radiographic examinations with bone scan, three (33%) showed partial response, two (22%) were stable and four (44%) showed disease progression. Treatment was well tolerated, except for one patient who suffered a severe pulmonary infection. CONCLUSION: Dexamethasone decreased PSA levels and produced subjective symptomatic improvement in the patients with stage D2 androgen-independent prostate cancer.     

人类雄激素非依赖性前列腺癌细胞模型的建立

目的　建立并论证雄激素非依赖性前列腺癌细胞模型。　方法　将雄激素依赖性父代LNCaPC 3 3细胞常规传代培养 ,LNCaP细胞生长对雄激素依赖性逐渐降低 ,建立前列腺癌雄激素非依赖性细胞模型。　结果　通过连续传代培养 ,雄激素依赖性C 3 3细胞 (传代次数 <3 3次 )生物学行为发生改变。C 81细胞 (传代次数 >80次 )表现出更强的生长能力 ,对雄激素的依赖性低于C 3 3和C 51细胞 (传代次数介于 3 4～ 81次之间 )。　结论　在未去除雄激素情况下建立的雄激素非依赖性LNCaPC 81细胞模型 ,可贴切反映临床前列腺癌进展过程 ,为前列腺癌雄激素非依赖性生长分子机理的研究提供实用的细胞模型     

Endopeptidase 24.11 activity in the human prostate cancer cell lines LNCaP and PPC-1

Human endopeptidase 24.11 (EP) occurs in greatest abundance on terminally differentiated prostate cells; thus, loss of EP could mark dedifferentiation of prostate epithelium. To identify laboratory models that would permit continuous work on the biochemistry and hormonal regulation of EP, we examined the well-differentiated LNCaP and poorly differentiated PPC-1 human prostate cancer cell lines. Ultrastructural analysis revealed that LNCaP secretes electron-dense material that resembles the particulate matter of seminal plasma, which is associated with endopeptidase activity. LNCaP medium contained EP activity while PPC-1 medium did not. Whether the apparent deletion of EP from the PPC-1 cell line is characteristic of poorly differentiated prostate adenocarcinoma is not yet clear. However, it may be relevant to the carcinogenic process that EP can limit growth of lung small carcinomas by inactivating cell growth-promoting bombesin-like peptides. Because bombesin has been identified in aggressive human prostate cancers, loss of EP in PPC-1 could represent a necessary step in transformation to aggressive phenotype. The combination of LNCaP and PPC-1, which offers well-differentiated and poorly differentiated cancer phenotypes, appears well suited to studying the relevance of EP in prostate cancer biology.     

Emodin induces apoptosis in human prostate cancer cell LNCaP

AIM: To elucidate effects and mechanisms of emodin in prostate cancer cells. METHODS: Viability of emodin-treated LNCaP cells and PC-3 cells was measured by MTT assay. Following emodin treatments, DNA fragmentation was assayed by agarose gel electrophoresis. Apoptosis rate and the expression of Fas and FasL were assayed by flow cytometric analysis. The mRNA expression levels of androgen receptor (AR), prostate-specific antigen (PSA), p53, p21, Bcl-2, Bax, caspase-3, -8, -9 and Fas were detected by RT-PCR, and the protein expression levels of AR, p53 and p21 were detected by Western blot analysis. RESULTS: In contrast to PC-3, emodin caused a marked increase in apoptosis and a decrease in cell proliferation in LNCaP cells. The expression of AR and PSA was decreased and the expression of p53 and p21 was increased as the emodin concentrations were increased. In the same time, emodin induced apoptosis of LNCaP cells through the upregulation of caspase-3 and -9, as well as the increase of Bax /Bcl-2 ratio. However, it did not involve modulation of Fas or caspase-8 protein expression. CONCLUSION: In prostate cancer cell line, LNCaP, emodin inhibites the proliferation by AR and p53-p21 pathways, and induces apoptosis via the mitochondrial pathway.     

Effects of galectin-3 expression on growth and tumorigenicity of the prostate cancer cell line LNCaP.

BACKGROUND: Galectin-3 is a beta-galactoside-binding vertebrate lectin. In human prostate cancer, galectin-3 expression has been shown to decrease with progression of disease. In the present study, we further investigated the role of galectin-3 in this malignancy by examining the phenotype of galectin-3-transfected prostate cancer cells. METHODS: Stably transfected galectin-3-expressing cell lines were developed from the prostate cancer cell line LNCaP, which does not constitutively express this molecule. Transfected cells lines were analyzed for alterations in morphology and growth rates, and for ability to form tumors in nude mice. RESULTS: Morphologically, when compared to the parental LNCaP cells, the galectin-3 transfectants had broader, flatter cell bodies, shorter and less finely branched dendritic processes, and large nuclei with pronounced and often multiple nucleoli. The galectin-3 lines were found to proliferate at a slower rate in vitro than either the vector control-transfected lines or parental LNCaP. When injected subcutaneously in nude mice, four of six galectin-3 lines formed tumors at a slower rate than control lines. Twenty-four tumors that formed from the transfected cell lines were examined by immunohistochemistry for galectin-3 expression. Only one tumor was found to express galectin-3, suggesting that the transfected cells which formed tumors were those which successfully down-regulated galectin-3 expression. CONCLUSIONS: In contrast to an apparent stimulatory role in some tumor types, galectin-3 is an inhibitory molecule for prostate cancer.     

Lineage relationship between LNCaP and LNCaP-derived prostate cancer cell lines

BACKGROUND: LNCaP and its derivative cell lines, which include C4-2 (and the related C4-2B) and CL1, are used as models of prostate cancer. Unlike LNCaP, the other cell lines show features of progressed disease such as metastatic capability and hormone independence. Analyses were done to determine if C4-2 or CL1 cells were selected from pre-existent subpopulations in LNCaP. METHODS: Prostate cancer cells were characterized by cluster designation (CD) phenotyping. Specific cell populations were sorted by flow cytometry. DNA array analysis was used to probe differential gene expression. RESULTS: CD phenotyping showed that CL1 and C4-2 (and C4-2B) were very dissimilar, and C4-2 was more similar to LNCaP. One common difference between LNCaP and its derivatives was CD26, in which virtually all C4-2 or CL1 cells were CD26(+) but only approximately 10% of LNCaP cells were CD26(+). The CD26(+) subpopulation of LNCaP was isolated and cultured in vitro. After culture, a high percentage of the cells (descended from the sorted cells) were CD26(+), in contrast to those sorted by CD13 or CD44. The cultured CD13 and CD44 populations did not show a high percentage of CD13(+) and CD44(+) cells, respectively. CD13 and CD44 are markers, in addition to CD26, for CL1 but not for C4-2. CONCLUSIONS: C4-2 arose probably from CD26(+) LNCaP cells, while CL1 arose de novo.     

Effects of bortezomib in sensitizing human prostate cancer cell lines to NK-mediated cytotoxicity

The proteasome inhibitor, bortezomib, has been demonstrated to sensitize tumor cells to tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-mediated apoptosis. Natural killer (NK) cells represent potent antitumor effector cells. They also express TRAIL. Therefore, we investigated whether bortezomib could sensitize tumor cells to NK cell-mediated killing, and have the same effect in human prostate cancer cell lines (LNCaP and DU145). We found that bortezomib strongly inhibits proliferation in both cell lines. Furthermore, compared with LNCaP cells, DU145 cells are more sensitive to bortezomib-induced apoptosis. However, bortezomib is unable to sensitize these two cell lines to NK cell-mediated killing in short-term assays. In long-term assays, we found that killing mediated by activated NK cells following bortezomib treatment leads to greater antitumor effects than either treatment alone. In addition, treatment with bortezomib causes these cells to upregulate apoptosis-related mRNA as well as death receptors and downregulate the major histocompatibility class (MHC)-I molecule on the cell surface of DU145 cells. In contrast, LNCaP cells are not sensitized by this treatment. Death receptors and the MHC-I molecule did not change in this cell line. These data suggest that bortezomib can be used to sensitize prostate cancer cells to NK cell-mediated killing and improve current cancer therapies. This therapeutic strategy may be more effective in patients with androgen-insensitive prostate cancer.     

Differential regulation of IGFBP-3 by the androgen receptor in the lineage-related androgen-dependent LNCaP and androgen-independent C4-2 prostate cancer models

BACKGROUND: Despite evidence implicating insulin-like growth factor binding protein-3 (IGFBP-3) as a growth inhibitor of prostate cancer (CaP), little is known about changes in its regulation and function during progression to androgen independence. METHODS: The expression levels of IGFBP-3 were determined by cDNA microarray analysis and tissue microarrays (TMAs) after androgen ablations. LNCaP (LN-BP3) and C4-2 (C4-2-BP3) sublines were used to compare the apoptotic effects of IGFBP-3 in LNCaP (androgen-dependent) and C4-2 (androgen-independent) cells. RESULTS: After androgen deprivation, IGFBP-3 mRNA levels increased more in C4-2 compared to LNCaP cells. Androgens suppressed IGFBP-3 levels in a dose-dependent manner in LNCaP and C4-2 cell. IGFBP-3 expression was increased after NHT in human CaP tissues. Apoptotic rates increased in LN-BP3, but not C4-2-BP3 cells, following doxycycline-mediated IGFBP-3 induction. CONCLUSIONS: C4-2 cell survival in an androgen-depleted environment may be facilitated through differential resistance to the apoptotic effects elicited by IGFBP-3.     

iNOS基因转染对雄激素非依赖性前列腺癌细胞DU145生长的影响

目的:观察诱导型一氧化氮合酶(iNOS)基因转染对雄激素非依赖性前列腺癌细胞DU145生物学行为的影响。方法:将iNOS基因转染到DU145细胞并筛选出阳性细胞进行扩增,并设空载体组和对照组。观察细胞的形态变化,MTT法绘制生长曲线;流式细胞术检测细胞凋亡率;了解NOS抑制剂对转染细胞的影响。结果:转染iNOS后,DU145细胞分泌的NO[(272.50±15.82)μmol/L]显著高于空载体组[(122.00±18.93)μmol/L]和对照组[(121.00±6.98)μmol/L](P<0.05)。流式细胞术检测结果提示转染iNOS组细胞凋亡率[(42.78±2.01)%]明显高于空载体组[(30.65±1.46)%]和对照组[(28.96±1.50)%](P<0.05)。MTT测定结果提示转染组细胞生长较空载体组和对照组减慢(P<0.05),NOS抑制剂可以加快其生长,但无显著性差异(P>0.05)。结论:iNOS基因转染可以使DU145细胞分泌较高浓度的NO,诱导细胞凋亡,抑制细胞生长,为晚期雄激素非依赖性前列腺癌的基因治疗提供一个有效的靶点。