Posterior lumbar vein off the retrohepatic inferior vena cava: a novel anatomical variant with surgical implications.

PURPOSE: Resection of tumors involving the inferior vena cava requires vascular control of posteriorly draining lumbar veins to ensure a bloodless field. Surgical texts and atlases assert that lumbar veins do not insert into the inferior vena cava superior to the renal hilum. However, at our institution we have encountered patients undergoing inferior vena cava tumor thrombectomy who have a posterior lumbar vein cephalad to the renal veins. Since this represents an unrecognized source of hemorrhage, we investigated the frequency of a superior lumbar vein in cadaveric dissection. MATERIALS AND METHODS: Retroperitoneal cadaveric dissection of the inferior vena cava was done to assess the frequency of a lumbar vein draining into the inferior vena cava cephalad to the renal veins. RESULTS: Of the 49 cadaveric dissections performed 19 (38.8%) showed a single posterior lumbar vein between the diaphragm and the renal hilum. Of these 19 cadavers 15 (78.9%) were male. This vein was located an average ± SD of 7.4 ± 0.6 cm cephalad to the right renal vein and it was 3.7 ± 1.6 cm in diameter. In all cadavers this vein inserted within 30 degrees to the left or right of the posterior (also termed dorsal) aspect of the inferior vena cava. CONCLUSIONS: The identification of a lumbar vein between the renal hilum and the diaphragm represents an important anatomical variant that occurs in a significant percent of individuals. Surgeons will benefit from the knowledge of this variant of inferior vena cava vasculature and should anticipate the presence of this vein to prevent unnecessary morbidity and mortality secondary to unexpected hemorrhage, particularly in male patients.

Active sonic hedgehog signaling between androgen independent human prostate cancer cells and normal/benign but not cancer-associated prostate stromal cells.

BACKGROUND: Sonic hedgehog (Shh) signaling plays a pivotal role in stromal-epithelial interaction during normal development but its role in tumor-stromal interaction during carcinogenic progression is less well defined. Since hormone refractory prostate cancer with bone metastasis is difficult to treat, it is crucial to investigate how androgen independent (AI) human prostate cancer cells communicate with their associated stroma. METHODS: Shh and its target transcription factor, Gli1 mRNA, were assessed by RT-PCR and/or quantitative RT-PCR in co-cultured cell recombinants comprised of AI C4-2 either with NPF (prostate fibroblasts from normal/benign prostate gland) or CPF (cancer-associated stromal fibroblasts) under Shh/cyclopamine (a hedgehog signaling inhibitor) treatment. Human bone marrow stromal (HS27A) cells were used as controls. In vivo investigation was performed by checking serum PSA and immunohistochemical staining for the apoptosis-associated M30 gene in mice bearing chimeric C4-2/NPF tumors. RESULTS: We found that (1) Shh has minimal growth-stimulating effects on prostate cancer cells, but it stimulated the growth of NPF but not CPF; (2) active Shh signaling was found between AI C4-2 cells and NPF but not CPF; and (3) osteonectin (ON) is a Gli1 target gene in NPF and not in CPF, and ON up-regulation in NPF can be blocked by cyclopamine CONCLUSIONS: Based on co-culture and chimeric tumor models, active Shh-mediated signaling was demonstrated between AI prostate cancer and NPF in a paracrine- and tumor progression-dependent manner. Our study suggests that drugs like cyclopamine that interfere with Shh signaling could be beneficial in preventing AI progression in prostate cancer cells.

Human prostate cancer harbors the stem cell properties of bone marrow mesenchymal stem cells.

PURPOSE: Prostate tumor cells frequently show the features of osteoblasts, which are differentiated from bone marrow mesenchymal stem cells. We examined human prostate cancer cell lines and clinical prostate cancer specimens for additional bone marrow mesenchymal stem cell properties. EXPERIMENTAL DESIGN: Prostate cancer cell lines were induced for osteoblastogenic and adipogenic differentiation, detected by standard staining methods and confirmed by lineage-specific marker expression. Abnormal expression of the markers was then assessed in clinical prostate cancer specimens. RESULTS: After osteoblastogenic induction, cells of the LNCaP lineage, PC-3 lineage, and DU145 displayed osteoblastic features. Upon adipogenic induction, PC-3 lineage and DU145 cells differentiated into adipocyte-like cells. The adipocyte-like cancer cells expressed brown adipocyte-specific markers, suggesting differentiation along the brown adipocyte lineage. The adipogenic differentiation was accompanied by growth inhibition, and most of the adipocyte-like cancer cells were committed to apoptotic death. During cyclic treatments with adipogenic differentiation medium and then with control medium, the cancer cells could commit to repeated adipogenic differentiation and retrodifferentiation. In clinical prostate cancer specimens, the expression of uncoupling protein 1 (UCP1), a brown fat-specific marker, was enhanced with the level of expression correlated to disease progression from primary to bone metastatic cancers. CONCLUSIONS: This study thus revealed that prostate cancer cells harbor the stem cell properties of bone marrow mesenchymal stem cells. The abnormally expressed adipogenic UCP1 protein may serve as a unique marker, while adipogenic induction can be explored as a differentiation therapy for prostate cancer progression and bone metastasis.

Comparison of 12-core versus 8-core prostate biopsy: multivariate analysis of large series of US veterans.

OBJECTIVES: To investigate the impact of additional biopsy cores on prostate cancer diagnosis among US veterans. The reported rate of positive biopsy results varies from 20% to 40%. METHODS: We analyzed 1546 consecutive initial prostate biopsy procedures (8-core and 12-core biopsy protocols) at the Atlanta VA Medical Center. Both biopsy protocols targeted the peripheral zone. Cancer detection rates were compared between the 2 protocols in univariate and multivariate analyses with results expressed as odds ratios and corresponding 95% confidence intervals. Characteristics of cancer detected were also compared. Sensitivity analyses were performed for different population subgroups. RESULTS: The overall positive biopsy rate was 49.9%, 51.2% in the 8-core group and 49.2% in the 12-core group. There was no difference between the 2 biopsy groups (adjusted odds ratio = 0.97, 95% confidence interval = 0.76-1.25). Advanced age and high body mass index were significantly associated with higher likelihood of prostate cancer, whereas larger prostate volumes were associated with lower risk. CONCLUSIONS: In this large series of prostate biopsy procedures, in which the peripheral zone was well targeted, there was no evidence that 12-core biopsy improved the likelihood of prostate cancer diagnosis compared with 8-core biopsy. As such, the results of this cohort from a US veteran population suggest that targeting the peripheral zone is more important than the absolute number of biopsy cores. However, in certain subgroups of patients with specific clinical characteristics, such as those with very large prostates, more cores may be required. Further studies are needed to identify such characteristics.

Expression of C-reactive protein and cyclooxygenase enzyme-2 in clear cell renal cell carcinoma: correlation with pathological parameters in 110 patients.

C-reactive protein is produced in response to cytokines such as interleukin (IL)-6. It is known that increased plasma IL-6 levels induce increased hepatic and intratumoral production of C-reactive protein. Cyclooxygenase enzyme-2 is induced by various stimuli, including inflammation and various growth factors. Expression of these two markers has not been well studied in clear cell renal cell carcinoma. The objective of this study is to correlate the expression of C-reactive protein and cyclooxygenase enzyme-2 in clear cell renal cell carcinoma with pathologic parameters. A search of the surgical pathology and consultation files at our institution was performed for nephrectomy specimens with clear cell renal cell carcinoma from 2007 to 2008. Immunohistochemical stains for C-reactive protein and cyclooxygenase enzyme-2 were performed. Staining intensity was graded as 0, 1+, 2+, and 3+. The staining intensity was then correlated with pathologic stage and Fuhrman nuclear grade for each case. A total of 110 cases were identified. Strong expression of C-reactive protein was associated with higher Fuhrman nuclear grade and pathologic stage, and the strength of correlation was statistically significant (p = 0.01 and p = 0.001), respectively. However, cyclooxygenase enzyme-2 expression did not show statistically significant correlation with both pathologic stage and Fuhrman nuclear grade (p = 0.1 and p = 0.15), respectively. To our knowledge, this is the largest study to date correlating the expression of both C-reactive protein and cyclooxygenase enzyme-2 in tissue with pathologic parameters in patients with clear cell renal cell carcinoma, which could have significant prognostic and therapeutic implications.

Matched pairs of human prostate stromal cells display differential tropic effects on LNCaP prostate cancer cells.

Prostate stromal cells may play binary roles in the process of prostate cancer development. As the first to be encountered by infiltrating prostate cancer cells, prostate stromal cells form the first defense line against prostate cancer progression and metastasis. However, interaction between prostate cancer and stromal cells may facilitate the formation of a tumor microenvironment favoring cancer cell growth and survival. To establish an experimental system for studying the interaction between cancer and stromal cells, we isolated three matched pairs of normal and cancer-associated human prostate stromal clones. In this report, we describe the morphologic and behavioral characteristics of these cells and their effect on LNCaP prostate cancer cells in co-culture. Unlike LNCaP prostate cancer cells, the isolated prostate stromal clones are large fibroblast-like cells with a slow proliferation rate. Growth and survival of these clones are not affected by androgens. The stromal cells display high resistance to serum starvation, while cancer-associated stromal clones have differentiated survival ability. In co-culture experiments, the stromal cells protected some LNCaP prostate cancer cells from death by serum starvation, and cancer-associated stromal clones showed more protection. This work thus established a panel of valuable human prostate stromal cell lines, which could be used in co-culture to study the interaction between prostate cancer and prostate stromal cells.

Impact of laparoscopic inguinal hernia repair mesh on open radical retropubic prostatectomy.

OBJECTIVES: Open radical retropubic prostatectomies (RRP) have been abandoned after previous laparoscopic inguinal hernia repair (LIHR) with mesh, which can be a relative contraindication to open RRP. Radiation therapy and radical perineal prostatectomy are alternative treatment options for prostate cancer when faced with this dilemma. Our objective is to report our experience with open RRP after LIHR. METHODS: A retrospective chart review was conducted from January 2000 to December 2007 of all open RRP executed by a single surgeon (F.F.M.) with prior LIHR. All information on LIHR, including laterality and its effect on pelvic lymphadenectomy (LAD), were analyzed. Pre-, intra-, and postoperative data were recorded. RESULTS: Of the 949 men who underwent RRP performed by this surgeon, a cohort of 21 men had prior LIHR (a total of 29 IHR: 13 unilateral and 8 bilateral). The mean age and PSA were 61.0 years and 5.8 ng/mL, respectively. Of the men, 18 and 3 men presented with T1c and T2a clinical stage, respectively. Preoperatively 18 men, 2 men, and 1 man had a Gleason score of 6, 3+4, and 8, respectively. All RRP subsequent to LIHR were successful with minimal complications. A total of 4, 4, 11, and 2 men had stage pT2a, pT2b, pT2c, and pT3a, respectively. Fifteen men (71%) had either unilateral (4 men) or bilateral (11) LAD (all pN0), whereas 6 men had no LAD because of severe pelvic scaring. CONCLUSIONS: Our experience demonstrates that open RRP after LIHR with mesh can typically be performed with minimal risks and in carefully selected patients for best outcomes, but LAD might be compromised.

XMRV infection in patients with prostate cancer: novel serologic assay and correlation with PCR and FISH.

OBJECTIVES: To develop a serum-based assay to detect neutralizing antibodies to the xenotropic murine leukemia virus-related virus (XMRV) retrovirus and to use this assay with polymerase chain reaction and fluorescence in situ hybridization to identify patients with prostate cancer previously exposed to XMRV infection and those who carry XMRV viral sequences in their prostate. METHODS: Patients who had undergone radical prostatectomy were enrolled, and biologic specimens were obtained at surgery. The patients were genotyped for the R462Q RNASEL variant using a TaqMan genotyping assay on DNA from the peripheral blood. A serum assay that detects XMRV neutralizing antibodies was developed and used to determine which patients had serologic evidence of previous infection with XMRV virus. Some of these patients were also tested for the presence of XMRV nucleotide sequences in their prostate using polymerase chain reaction and fluorescence in situ hybridization analysis. RESULTS: At a serum dilution of 1:150, our assay detected 11 (27.5%) of 40 patients with XMRV neutralizing antibodies, including 8 (40%) of 20 with the RNASEL genotype QQ and 3 (15%) of 20 with either the RQ or RR genotype. These results were in complete concordance with 2 other assays (polymerase chain reaction and fluorescence in situ hybridization), which were designed to detect XMRV infection. CONCLUSIONS: XMRV infects some patients with prostate cancer. Neutralizing antibodies against XMRV correlated with 2 independent methods of detecting the virus in the prostate. The antibody response suggests that with clinical serologic assay development, it might be possible to screen patients for XMRV infection. The cases presented in the present report provided biologic samples that can be used for the development of a clinically relevant assay.

Phorbol ester phorbol-12-myristate-13-acetate induces epithelial to mesenchymal transition in human prostate cancer ARCaPE cells.

BACKGROUND: We have reported that human prostate cancer ARCaP(E) cells undertake epithelial to mesenchymal transition (EMT) when stimulated by certain soluble factors, and that EMT is regulated by surface receptor-elicited signaling pathways through protein phosphorylation. It is known that phorbol ester phorbol-12-myristate-13-acetate (PMA), a potent antagonist to both conventional and novel protein kinase C (PKC) isoenzymes, induces cancer cell scattering. METHODS: To assess the effect of PMA on EMT, ARCaP(E) cells were treated with PMA and were assayed for EMT-related morphologic and behavioral changes. Specific inhibitors were used to investigate the PMA-induced EMT. RESULTS: PMA at 100 nM induced EMT in a time-dependent manner, resulting in a complete change from epithelial to mesenchymal stromal morphology. Concurrently, PMA inhibited expression of epithelial marker E-cadherin and increased the level of stromal marker protein vimentin, while the treated cells showed increased migratory and invasive capacities. Using specific inhibitors, we confirmed that the effect of PMA was mediated by PKC, while isoenzymes of the novel PKC subfamily were implicated as the main mediator. Finally, we determined that the EMT was dependent on newly synthesized proteins, because inhibitors for gene transcription and protein translation could both inhibit the initiation of EMT. CONCLUSIONS: Although PMA is well known for its effects on cell migration and tumor formation, this work is the first to define PMA as an EMT inducer in prostate cancer cells. Further investigation in this experimental model may reveal important regulatory mechanisms and additional molecular changes underlying EMT.

Differential expression of the alpha2 chain of the interleukin-13 receptor in metastatic human prostate cancer ARCaPM cells.

BACKGROUND: The alpha2 chain of the interleukin-13 receptor (IL13Ralpha2) is a high-affinity receptor and a candidate target for cytotoxic killing of cancer cells. Availability of a human prostate cancer cell line with high level of IL13Ralpha2 expression will facilitate the development of therapeutic modalities. METHODS: ARCaP(E) and ARCaP(M) human prostate cancer cell lines were subjected to comparative analyses of gene expression. Expression of the IL13Ralpha2 protein was confirmed by Western blotting and immunostaining. IL13Ralpha2 proteins in xenograft tumors and clinical human prostate cancer specimens were detected by specific antibodies. LNCaP prostate cancer cells stably transfected with IL13Ralpha2 were examined for accelerated growth in athymic mice. RESULTS: We found that IL13Ralpha2 proteins could be detected in both the ARCaP(E) and ARCaP(M) cells, but the expression level in ARCaP(M) was more than 17-fold higher than in ARCaP(E) cells. Importantly, the ARCaP lineage represented the only human prostate cancer cell line that expresses IL13Ralpha2 proteins at the level detectable by Western blotting. Expression of IL13Ralpha2 was accompanied by resistance to the anti-tumor activity of interleukin-13 (IL-13). ARCaP cells were found to be insensitive to growth inhibition upon IL-13 treatment, while overexpression of IL13Ralpha2 in LNCaP cells promoted intratibial tumor growth in athymic mice. CONCLUSIONS: Differential IL13Ralpha2 expression may account for the high tumorigenic and metastatic potential of ARCaP(M) cells. The unique expression of IL13Ralpha2 makes ARCaP lineage an attractive model for evaluating the targeting efficacy of therapeutic agents based on IL13Ralpha2 protein expression.

Vascular endothelial growth factor regulates myeloid cell leukemia-1 expression through neuropilin-1-dependent activation of c-MET signaling in human prostate cancer cells.

BACKGROUND: Myeloid cell leukemia-1 (Mcl-1) is a member of the Bcl-2 family, which inhibits cell apoptosis by sequestering pro-apoptotic proteins Bim and Bid. Mcl-1 overexpression has been associated with progression in leukemia and some solid tumors including prostate cancer (PCa). However, the regulatory mechanism for Mcl-1 expression in PCa cells remains elusive. RESULTS: Immunohistochemical analyses revealed that Mcl-1 expression was elevated in PCa specimens with high Gleason grades and further significantly increased in bone metastasis, suggesting a pivotal role of Mcl-1 in PCa metastasis. We further found that vascular endothelial growth factor (VEGF) is a novel regulator of Mcl-1 expression in PCa cells. Inhibition of endogenous Mcl-1 induced apoptosis, indicating that Mcl-1 is an important survival factor in PCa cells. Neuropilin-1 (NRP1), the "co-receptor" for VEGF165 isoform, was found to be highly expressed in PCa cells, and indispensible in the regulation of Mcl-1. Intriguingly, VEGF165 promoted physical interaction between NRP1 and hepatocyte growth factor (HGF) receptor c-MET, and facilitated c-MET phosphorylation via a NRP1-dependent mechanism. VEGF165 induction of Mcl-1 may involve rapid activation of Src kinases and signal transducers and activators of transcription 3 (Stat3). Importantly, NRP1 overexpression and c-MET activation were positively associated with progression and bone metastasis in human PCa specimens and xenograft tissues. CONCLUSIONS: This study demonstrated that Mcl-1 overexpression is associated with PCa bone metastasis. Activation of VEGF165-NRP1-c-MET signaling could confer PCa cells survival advantages by up-regulating Mcl-1, contributing to PCa progression.

Progressive epithelial to mesenchymal transitions in ARCaP E prostate cancer cells during xenograft tumor formation and metastasis.

BACKGROUND: The mechanism of epithelial to mesenchymal transition (EMT) could be adopted by tumor cells for migration and invasion. We have reported that ARCaP(E) human prostate cancer cells undergo EMT-like changes during xenograft growth in athymic mice. METHODS: In this report, we assessed the extent of EMT by tracking changes in cloned ARCaP(E) cells expressing red fluorescence protein during successive orthotopic prostate tumor formation. Cancer cells with stromal-like morphology were isolated and examined for EMT-like changes. RESULTS: EMT-like morphologic and expression changes were detected after one round of in vivo tumor formation. Importantly, when recovered tumor cells were used in second round xenograft tumor formation, a large fraction of ARCaP(E) cells showed drastic EMT-like changes, with markedly enlarged cell size and divergent cell shapes similar to those of mesenchymal stromal cells. The morphologic change was accompanied by increased growth and metastasis, as tumor incidence increased while red fluorescent tumor cells could be detected from circulating blood, bone marrow, peritoneal ascites, and lung of the tumor-bearing mice. Recovered clones from these samples had lost epithelial markers but many showed activated stromal marker vimentin expression. The EMT appeared permanent since the newly acquired morphology was sustained after continuous passages. CONCLUSIONS: Results from this study demonstrate that through interaction with the host tumor microenvironment, cancer cells acquire cellular plasticity. During xenograft tumor formation and metastasis, a single clone of cancer cells could yield a heterogeneous population, with a substantial number of tumor cells adopting mesenchymal stroma-like phenotypes.

Human prostate fibroblasts induce growth and confer castration resistance and metastatic potential in LNCaP Cells.

BACKGROUND: The tumor microenvironment is important for progressive and metastatic disease. OBJECTIVE: To study the hypothesis that prostate fibroblasts have differential ability to induce castration-resistant prostate cancer (PCa) and metastatic progression and whether this effect might vary depending on the zonal origin of the fibroblast. DESIGN, SETTING, AND PARTICIPANTS: Human prostate fibroblasts from the peripheral (PZ), transition (TZ) and central (CZ) zones of radical prostatectomy specimens (n=13) were isolated and compared for their ability to promote androgen independence and metastatic progression in androgen-responsive PCa lymph node carcinoma of the prostate (LNCaP) cells in vivo. INTERVENTIONS: By coinoculating marginally tumorigenic LNCaP cells with PZ or TZ and by altering host hormonal milieu, a series of tumorigenic and metastatic LNCaP epithelial sublines-P4, P4-2 (derivatives from interaction with PZ), T4, and T4-2 (derivatives from interaction with TZ)-were established and characterized. MEASUREMENTS: In vivo and in vitro evaluation of induction of tumor growth and metastatic potential. RESULTS AND LIMITATIONS: 1) LNCaP sublines were permanently altered in their cytogenetic and biologic profiles after cellular interaction with prostate stromal fibroblasts. LNCaP sublines grew faster under anchorage-dependent and -independent conditions, expressed 1-12-fold more prostate-specific antigen in vitro than LNCaP cells, and gained metastatic potential; 2) zonal differences of stromal fibroblasts in their ability to induce the growth and progression of LNCaP tumors as xenografts in mice may exist but need further analysis; 3) PZ-conditioned medium induced more anchorage-independent growth of LNCaP cells in vitro. TZ had a higher growth rate and were more sensitive to dihydrotestosterone. CONCLUSIONS: We demonstrate that prostate fibroblasts have growth inductive potential on PCa cells and affect their subsequent progression to castration resistance and development of a metastatic phenotype.

The utilization of Gleason grade as the primary criterion for ordering nuclear bone scan in newly diagnosed prostate cancer patients.

Utilization of nuclear bone scans for staging newly diagnosed prostate cancer has decreased dramatically due to PSA-driven stage migration. The current criteria for performing bone scans are based on limited historical data. This study evaluates serum PSA and Gleason grade in predicting positive scans in a contemporary large series of newly diagnosed prostate cancer patients. Eight hundred consecutive cases of newly diagnosed prostate cancer over a 64-month period underwent a staging nuclear scan. All subjects had histologically confirmed cancer. The relationship between PSA, Gleason grade, and bone scan was examined by calculating series of crude, stratified, and adjusted odds ratios with corresponding 95% confidence intervals. Four percent (32/800) of all bone scans were positive. This proportion was significantly lower in patients with Gleason score or=8 (18.8%, p < 0.001). Among patients with Gleason score 30 ng/ml compared to or=8, the rate was significantly higher (27.9 vs. 0%) when PSA was >10 ng/ml compared to 30 ng/ml. However, for patients with a high Gleason score (8-10), we recommend a bone scan if the PSA is >10 ng/ml.

Transcription variants of the prostate-specific PrLZ gene and their interaction with 14-3-3 proteins.

We have reported isolation and characterization of the prostate-specific and androgen-regulated PrLZ gene abnormally expressed in prostate cancer. PrLZ is a potential biomarker for prostate cancer and a candidate oncogene promoting cell proliferation and survival in prostate cancer cells. A full delineation of the PrLZ gene and its gene products may provide clues to the mechanisms regulating its expression and function. In this report, we identified three additional exons in the PrLZ gene and recognized five transcript variants from alternative splicing that could be detected by RT-PCR and Western blotting. Structural comparison demonstrated that the PrLZ proteins are highly conserved among species. PrLZ contains multiple potential sites for interaction with other proteins. We used mammalian two-hybrid assays to demonstrate that PrLZ isoforms interact with 14-3-3 proteins, and multiple sites in the PrLZ may be involved in the interaction. Alternative splicing may contribute to abnormally enhanced PrLZ levels in prostate cancer, and interaction with 14-3-3 proteins may be a mechanism by which PrLZ promotes cell proliferation and survival during prostate cancer development and progression. This information is a valuable addition to the investigation of the oncogenic properties of the PrLZ gene.

Increased low density lipoprotein and increased likelihood of positive prostate biopsy in black americans.

PURPOSE: Differences in prostate cancer incidence, grade and stage at diagnosis, and survival in black vs nonblack men are well documented. Recent studies indicate that lipids may have a role in oncogenesis, including that of prostate cancer. We investigated the relationship between circulating lipids in black and nonblack patients, and newly diagnosed prostate cancer. MATERIALS AND METHODS: The study population included consecutive patients who underwent prostate biopsy for increased prostate specific antigen and/or abnormal digital rectal examination at Atlanta Veterans Affairs Medical Center. Age, race, prostate specific antigen, prostate volume, body mass index, family history, high and low density lipoprotein, triglyceride and cholesterol lowering medications were included in data analysis. RESULTS: A total of 1,775 men with complete information were included in data analysis. A total of 521 black and 451 white men had positive biopsies. Using 100 mg/dl or less as the referent the adjusted OR reflecting the association of low density lipoprotein and prostate cancer diagnosis in black men was 1.49 (95% CI 1.04-2.13, p = 0.031), 1.51 (95% CI 0.96-2.39, p = 0.076) and 3.24 (95% CI 1.59-6.92, p = 0.002) for low density lipoprotein greater than 100 to 130, greater than 130 to 160 and greater than 160 mg/dl, respectively. Corresponding results in nonblack men showed no significant association. CONCLUSIONS: Increased serum low density lipoprotein is associated with an increased likelihood of prostate cancer diagnosis in black men but not in nonblack men. This association is strongest in the highest low density lipoprotein risk category. The reasons for the racial differences are unknown but may include genetic, dietary or other environmental factors.

Soluble factors derived from stroma activated androgen receptor phosphorylation in human prostate LNCaP cells: roles of ERK/MAP kinase.

BACKGROUND: Accumulated evidence suggests stromal-epithelial interactions are critical to the progression of prostate cancer. In this study, we characterized AR phosphorylation in LNCaP cells co-cultured with the conditioned medium (CM) from human prostate stromal fibroblasts. METHODS: CM harvested from prostate stromal fibroblasts was added to LNCaP cells, and both anchorage-dependent and -independent growth was determined. Status of AR phosphorylation at Ser-81 and Ser-213 was assessed by immunoblot analysis. ERK kinase activity was measured using MBP-2 protein as the substrate. RESULTS: The growth of LNCaP cells on plastic dishes increased by 1.7-fold upon exposure to stromal CM or androgen, and their combination resulted in additive growth (2.4-fold). Anchorage-independent growth of LNCaP cells in soft agar, however, was induced synergistically at 80-fold by both stromal CM and androgen. Stromal CM or androgen alone induced LNCaP cell growth by 10- and 26-fold, respectively. We observed ERK kinase inhibitor, U0126, but not phosphatidylinositol 3-kinase (PI-3K), LY294002, or protein kinase A (PKA) inhibitor, H-89, inhibited stromal CM or androgen-induced PSA promoter luciferase activities, and anchorage-independent growth of LNCaP cells. Our results demonstrated for the first time how stromal CM acts in synergy with androgen by activation of ERK kinase and AR phosphorylation at Ser-81 but not Ser-213, for AR-regulated PSA promoter and anchorage-independent growth of human prostate cancer cells. CONCLUSIONS: A stromal factor-activated ERK pathway mediated by AR phosphorylation at Ser-81 could be responsible for stimulating the growth of human prostate cancer cells.