Expression of multiple angiogenic cytokines in cultured normal human prostate epithelial cells: predominance of vascular endothelial growth factor

Biomolecules Involved in Both Metastasis and Placenta Accreta Spectrum-Does the Common Pathophysiological Pathway Exist?

The process of epithelial-to-mesenchymal transition (EMT) is crucial in the implantation of the blastocyst and subsequent placental development. The trophoblast, consisting of villous and extravillous zones, plays different roles in these processes. Pathological states, such as placenta accreta spectrum (PAS), can arise due to dysfunction of the trophoblast or defective decidualization, leading to maternal and fetal morbidity and mortality. Studies have drawn parallels between placentation and carcinogenesis, with both processes involving EMT and the establishment of a microenvironment that facilitates invasion and infiltration. This article presents a review of molecular biomarkers involved in both the microenvironment of tumors and placental cells, including placental growth factor (PlGF), vascular endothelial growth factor (VEGF), E-cadherin (CDH1), laminin γ2 (LAMC2), the zinc finger E-box-binding homeobox (ZEB) proteins, αVβ3 integrin, transforming growth factor β (TGF-β), β-catenin, cofilin-1 (CFL-1), and interleukin-35 (IL-35). Understanding the similarities and differences in these processes may provide insights into the development of therapeutic options for both PAS and metastatic cancer.

Role of vitamin D in targeting cancer and cancer stem cell populations and its therapeutic implications

Cancer is recognized globally as the second-most dominating and leading cause of morbidities. Fighting the global health epidemic threat posed by cancer requires progress and improvements in imaging techniques, surgical techniques, radiotherapy, and chemotherapy. The existence of a small subpopulation of undifferentiated cells known as cancer stem cells has been supported by accumulating evidence and ongoing research. According to clinical data, cancer recurrence, tumor development, and metastasis are thought to be caused by CSCs. Nutritional or dietary supplements can help you to fight against cancer and cope with the treatment side effects. Vitamin D, sometimes known as the sunshine vitamin, is produced in the skin in reaction to sunlight. Vitamin D deficiency is hazardous to any degree, increasing the risk of diseases such as cancer and disorders like osteoporosis. Bioactive vitamin D, or calcitriol, regulates several biological pathways. Many modes of action of Vitamin D might be helpful in protecting somatic stem cells (e.g., DNA damage repair and oxidative stress protection) or restricting cancer stem cell growth (e.g., cell cycle arrest, cell apoptosis). Researchers have recently begun to investigate the inhibitory effects of dietary vitamin D on cancer stem cells. In this review, we investigated the therapeutic impact of vitamin D and its molecular processes to target cancer and cancer stem cells as well.

The Synergistic Cooperation between TGF-β and Hypoxia in Cancer and Fibrosis

Transforming growth factor β (TGF-β) is a multifunctional cytokine regulating homeostasis and immune responses in adult animals and humans. Aberrant and overactive TGF-β signaling promotes cancer initiation and fibrosis through epithelial–mesenchymal transition (EMT), as well as the invasion and metastatic growth of cancer cells. TGF-β is a key factor that is active during hypoxic conditions in cancer and is thereby capable of contributing to angiogenesis in various types of cancer. Another potent role of TGF-β is suppressing immune responses in cancer patients. The strong tumor-promoting effects of TGF-β and its profibrotic effects make it a focus for the development of novel therapeutic strategies against cancer and fibrosis as well as an attractive drug target in combination with immune regulatory checkpoint inhibitors. TGF-β belongs to a family of cytokines that exert their function through signaling via serine/threonine kinase transmembrane receptors to intracellular Smad proteins via the canonical pathway and in combination with co-regulators such as the adaptor protein and E3 ubiquitin ligases TRAF4 and TRAF6 to promote non-canonical pathways. Finally, the outcome of gene transcription initiated by TGF-β is context-dependent and controlled by signals exerted by other growth factors such as EGF and Wnt. Here, we discuss the synergistic cooperation between TGF-β and hypoxia in development, fibrosis and cancer.

The Vitamin D Receptor as Tumor Suppressor in Skin

Cutaneous malignancies including melanomas and keratinocyte carcinomas (KC) are the most common types of cancer, occurring at a rate of over one million per year in the United States. KC, which include both basal cell carcinomas and squamous cell carcinomas, are substantially more common than melanomas and form the subject of this chapter. Ultraviolet radiation (UVR), both UVB and UVA, as occurs with sunlight exposure is generally regarded as causal for these malignancies, but UVB is also required for vitamin D synthesis in the skin. Keratinocytes are the major cell in the epidermis. These cells not only produce vitamin D but contain the enzymatic machinery to metabolize vitamin D to its active metabolite, 1,25(OH)₂D, and express the receptor for this metabolite, the vitamin D receptor (VDR). This allows the cell to respond to the 1,25(OH)₂D that it produces. Based on our own data and that reported in the literature, we conclude that vitamin D signaling in the skin suppresses UVR-induced epidermal tumor formation. In this chapter we focus on four mechanisms by which vitamin D signaling suppresses tumor formation. They are inhibition of proliferation/stimulation of differentiation with discussion of the roles of hedgehog, Wnt/β-catenin, and hyaluronan/CD44 pathways in mediating vitamin D regulation of proliferation/differentiation, regulation of the balance between oncogenic and tumor suppressor long noncoding RNAs, immune regulation, and promotion of DNA damage repair (DDR).

Long term deficiency of vitamin D in germ cell testicular cancer survivors

Background

Cisplatin-based chemotherapy significantly improved the survival of patients with germ cell testicular cancer. However, long term side effects of chemotherapy have non-negligible impact on the quality of life of these young patients, who have a long life expectancy after being successfully treated.

Materials and Methods

25-OH vitamin D, testosterone, FSH and LH of patients with testicular cancer were retrospectively evaluated and for each patient clinical information were collected. The tissue of 52 patients with germ cell tumors was analyzed for VDR expression by immunohistochemistry. The serum 25-OH vitamin D and VDR expression were correlated to the patients 'clinical characteristics.

Results

25-OH vitamin D was analyzed in 82 patients. Insufficient (< 30 ng/ml) levels were detected in 65%-85%, mild deficient (< 20 ng/ml) in 25%-36% and severe deficient (< 10 ng/ml) in 6%-18% of the patients over a median follow-up of 48 months. No difference in serum 25-OH vitamin D was detected over the follow-up time points. No correlation with histology, stage and type of treatment was found. The 25-OH vitamin D levels were not correlated to testosterone, FSH and LH levels. Interestingly, the expression of VDR was much higher in non seminoma than in seminoma tissue.

Conclusions

Patients with testicular cancer have reduced vitamin D levels after the treatment of the primary cancer. Since long term hypovitaminosis D leads to high risk of fractures, infertility and cardiovascular diseases, we envision that vitamin D should be regularly checked in patients with testicular cancer and replaced if needed.

High miR-205 expression in normal epithelium is associated with biochemical failure - an argument for epithelial crosstalk in prostate cancer?

Due to insufficient prognostic tools, failure to predict aggressive prostate cancer (PC) has left patient selection for radical treatment an unsolved challenge. This has resulted in overtreatment with radical therapy. Better prognostic tools are urgently warranted. MicroRNAs (miRs) have emerged as important regulators of cellular pathways, resulting in altered gene expressions. miR-205 has previously been observed downregulated in PC, acting as tumor suppressor. Herein, the expression of miR-205 in prostate tissue was examined in a large, well-described cohort of 535 Norwegian prostatectomy patients. Using in situ hybridization, miR-205 expression was semiquantatively measured in normal and tumor tissues from radical prostatectomy specimens. Associations with clinicopathological data and PC relapse were calculated. Expression of miR-205 was lower in tumor epithelium compared to normal epithelium. No association was observed between miR-205 expression in primary tumor epithelium and cancer relapse. In contrast, high expression of miR-205 in normal epithelium was independently associated with biochemical relapse (HR = 1.64, p = 0.003). A prognostic importance of miR-205 expression was only found in the normal epithelium, raising the hypothesis of epithelial crosstalk between normal and tumor epithelium in PC. This finding supports the proposed novel hypothesis of an anti-cancerogenous function of normal epithelium in tumor tissue.

A Network Biology Approach Identifies Molecular Cross-Talk between Normal Prostate Epithelial and Prostate Carcinoma Cells

The advent of functional genomics has enabled the genome-wide characterization of the molecular state of cells and tissues, virtually at every level of biological organization. The difficulty in organizing and mining this unprecedented amount of information has stimulated the development of computational methods designed to infer the underlying structure of regulatory networks from observational data. These important developments had a profound impact in biological sciences since they triggered the development of a novel data-driven investigative approach. In cancer research, this strategy has been particularly successful. It has contributed to the identification of novel biomarkers, to a better characterization of disease heterogeneity and to a more in depth understanding of cancer pathophysiology. However, so far these approaches have not explicitly addressed the challenge of identifying networks representing the interaction of different cell types in a complex tissue. Since these interactions represent an essential part of the biology of both diseased and healthy tissues, it is of paramount importance that this challenge is addressed. Here we report the definition of a network reverse engineering strategy designed to infer directional signals linking adjacent cell types within a complex tissue. The application of this inference strategy to prostate cancer genome-wide expression profiling data validated the approach and revealed that normal epithelial cells exert an anti-tumour activity on prostate carcinoma cells. Moreover, by using a Bayesian hierarchical model integrating genetics and gene expression data and combining this with survival analysis, we show that the expression of putative cell communication genes related to focal adhesion and secretion is affected by epistatic gene copy number variation and it is predictive of patient survival. Ultimately, this study represents a generalizable approach to the challenge of deciphering cell communication networks in a wide spectrum of biological systems.

In the current era of cancer research, stimulated by the release of the entire human genome, it has become increasingly clear that to understand cancer we need to understand how the many thousands of genes and proteins involved interact. Modern techniques have enabled the collection of unprecedented amounts of high quality data describing the state of these molecules during cancer development. In cancer research particularly, this strategy has been particularly successful, leading to the discovery of new drugs able to target key factors promoting cancer growth. However, a large body of research suggests that in complex organs, the interaction between cancer and its surrounding environment is an essential part of the biology of both diseased and healthy tissues, therefore it is of paramount importance that this process is further investigated. Here we report a strategy designed to reveal communication signals between cancer cells and adjacent cell types. We apply the strategy to prostate cancer and find that normal cells surrounding the tumour do exert an anti-tumour activity on prostate cancer cells. By using a statistical model which integrates multiple levels of genetic data, we show that cell-to-cell communication genes are controlled by DNA alterations and have potential prognostic value.

Stromal nodules in benign prostatic hyperplasia: morphologic and immunohistochemical characteristics

BACKGROUND

One hundred forty nine stromal nodules (SNs) from transurethral resection of benign prostatic hyperplasia specimens in 39 patients (57-85 years with mean of 70.9) were investigated to characterize the SNs and to outline the etiopathogenesis of solitary fibrous tumors (SFTs) and gastrointestinal stromal tumors (GISTs) of prostate by immunohistochemistry performed on tissue microarray sections.

METHODS

Antibodies used included smooth muscle actin, desmin, vimentin, and S-100 protein for subtyping, vascular endothelial growth factor, insulin-like growth factor-1, fibroblast growth factor, and TGF-ß as growth factors; CD133, c-KIT, CD34, and CD44 as stem cell markers; and estrogen (ER), progesterone (PR), and androgen receptor (AR) as hormone receptors.

RESULTS

SNs were classified into four subtypes: (1) immature mesenchymal (n = 7, 4.7%); (2) fibroblastic (n = 74, 49.7%); (3) fibromuscular (n = 53, 35.6%); and (4) smooth muscular (n = 15, 10.1%) types. There were linear trends of the expression of all growth factors (VEGF, IGF-1, FGF, TGF-ß), but only CD44 stem cell marker and AR hormone receptor as maturation progressed from immature mesenchymal to smooth muscular type (Ptrend  < 0.05). S-100, c-KIT, and ER were not expressed in any types of SNs. CD34 was positive in 55% of the SNs (82/149).

CONCLUSIONS

The data suggest that AR and growth factors are important factors for maturation of SNs, but not influenced by the administration of 5-alpha reductase inhibitor (5ARI). Although the cells comprising the SNs seem to be not associated with the origin of prostatic GISTs, there is a possibility of a tentative link of SFTs arising from SNs of the prostate.

Apigenin inhibits TGF-β-induced VEGF expression in human prostate carcinoma cells via a Smad2/3- and Src-dependent mechanism

Cancer progression relies on establishment of the blood supply necessary for tumor growth and ultimately metastasis. Prostate cancer mortality is primarily attributed to development of metastases rather than primary, organ-confined disease. Vascular endothelial growth factor (VEGF) is a key regulator of angiogenesis in prostate tissue. Our previous studies have demonstrated that the chemopreventive bioflavonoid apigenin inhibited hypoxia-induced elevation of VEGF production at low oxygen conditions characteristic for solid tumors. Low oxygen (hypoxia) and transforming growth factor-β (TGF-β) are two major factors responsible for increased VEGF secretion. In the present study, experiments were performed to investigate the inhibitory effect of apigenin on TGF-β-induced VEGF production and the mechanisms underlying this action. Our results demonstrate that VEGF expression is induced by TGF-β1 in human prostate cancer PC3-M and LNCaP C4-2B cells, and treatment with apigenin markedly decreased VEGF production. Additionally, apigenin inhibited TGF-β1-induced phosphorylation and nuclear translocation of Smad2 and Smad3. Further experiments demonstrated that specific transient knockdown of Smad2 or Smad3 blunted apigenin's effect on VEGF expression. We also found that apigenin inhibited Src, FAK, and Akt phosphorylation in PC3-M and LNCaP C4-2B cells. Furthermore, constitutively active Src reversed the inhibitory effect of apigenin on VEGF expression and Smad2/3 phosphorylation. Taken together, our results suggest that apigenin inhibits prostate carcinogenesis by modulating TGF-β-activated pathways linked to cancer progression and metastases, in particular the Smad2/3 and Src/FAK/Akt pathways. These findings provide new insights into molecular pathways targeted by apigenin, and reveal a novel molecular mechanism underlying the antiangiogenic potential of apigenin.

Vitamin D and cancer: a review of molecular mechanisms

The population-based association between low vitamin D status and increased cancer risk can be inconsistent, but it is now generally accepted. These relationships link low serum 25OHD (25-hydroxyvitamin D) levels to cancer, whereas cell-based studies show that the metabolite 1,25(OH)2D (1,25-dihydroxyvitamin D) is a biologically active metabolite that works through vitamin D receptor to regulate gene transcription. In the present review we discuss the literature relevant to the molecular events that may account for the beneficial impact of vitamin D on cancer prevention or treatment. These data show that although vitamin D-induced growth arrest and apoptosis of tumour cells or their non-neoplastic progenitors are plausible mechanisms, other chemoprotective mechanisms are also worthy of consideration. These alternative mechanisms include enhancing DNA repair, antioxidant protection and immunomodulation. In addition, other cell targets, such as the stromal cells, endothelial cells and cells of the immune system, may be regulated by 1,25(OH)2D and contribute to vitamin D-mediated cancer prevention.

Regulation of soluble VEGFR-2 secreted by microvascular endothelial cells derived from human BPH

BACKGROUND

Recently, it was reported that the soluble vascular endothelial growth factor receptor-2 (sVEGFR-2) is secreted by microvascular endothelial cells from human BPH (HPECs). The purpose of this study was to investigate the modulation of sVEGFR-2 by common endothelial cell stimulators. In addition, the physiological role of sVEGFR-2 with regard to the VEGF-stimulated proliferation of HPEC was investigated.

METHODS

HPECs were isolated and cultured from fresh BPH tissue. After the incubation of HPECs either with adenosine triphosphate (ATP), interleukin (IL)-6, IL-8 or IL-12, the secretion of sVEGFR-2 was measured by enzyme-linked immunosorbent assay. For measurement of HPEC proliferation influenced by sVEGFR-2, VEGF-stimulated HPEC was cultured with/without sVEGFR-2. Cell proliferation was assessed with the Alamar Blue method.

RESULTS

The sVEGFR-2 secretion was increased by ATP and decreased by IL-12 and IL-8, respectively. IL-6 did not show any significant effect on sVEGFR-2 secretion of HPECs. HPEC proliferation was significantly inhibited by sVEGFR-2.

CONCLUSIONS

In this study, our data suggest that the secretion of sVEGFR-2 by microvascular endothelial cells from prostate origin is influenced by multiple endothelial cell stimulators. Furthermore, our data suggest that sVEGFR-2 acts as an antiangiogenic factor.

1,25 dihydroxyvitamin D-mediated orchestration of anticancer, transcript-level effects in the immortalized, non-transformed prostate epithelial cell line, RWPE1

Background

Prostate cancer is the second leading cause of cancer mortality among US men. Epidemiological evidence suggests that high vitamin D status protects men from prostate cancer and the active form of vitamin D, 1α,25 dihydroxyvitamin D₃ (1,25(OH)₂D) has anti-cancer effects in cultured prostate cells. Still, the molecular mechanisms and the gene targets for vitamin D-mediated prostate cancer prevention are unknown.

Results

We examined the effect of 1,25(OH)₂D (+/- 100 nM, 6, 24, 48 h) on the transcript profile of proliferating RWPE1 cells, an immortalized, non-tumorigenic prostate epithelial cell line that is growth arrested by 1,25(OH)₂D (Affymetrix U133 Plus 2.0, n = 4/treatment per time and dose). Our analysis revealed many transcript level changes at a 5% false detection rate: 6 h, 1571 (61% up), 24 h, 1816 (60% up), 48 h, 3566 (38% up). 288 transcripts were regulated similarly at all time points (182 up, 80 down) and many of the promoters for these transcripts contained putative vitamin D response elements. Functional analysis by pathway or Gene Set Analysis revealed early suppression of WNT, Notch, NF-kB, and IGF1 signaling. Transcripts related to inflammation were suppressed at 6 h (e.g. IL-1 pathway) and suppression of proinflammatory pathways continued at later time points (e.g. IL-17 and IL-6 pathways). There was also evidence for induction of anti-angiogenic pathways and induction of transcripts for protection from oxidative stress or maintenance of cell redox homeostasis at 6 h.

Conclusions

Our data reveal of large number of potential new, direct vitamin D target genes relevant to prostate cancer prevention. In addition, our data suggests that rather than having a single strong regulatory effect, vitamin D orchestrates a pattern of changes within prostate epithelial cells that limit or slow carcinogenesis.

Secretion of soluble VEGF receptor 2 by microvascular endothelial cells derived by human benign prostatic hyperplasia

Vascular endothelial growth factor (VEGF) is one of the most potent mitogenic factors stimulating both prostate endothelial and prostate epithelial cells. Recently, some studies reported on the endothelial secretion of a soluble VEGF receptor 2 (sVEGFR-2) that modifies the free VEGF concentration by binding VEGF. For the first time in this study, we report on the secretion and the regulation of the secretion of sVEGFR-2 by microvascular endothelial cells derived from the tissue of human benign prostatic hyperplasia (HPEC). HPEC were isolated and cultured from fresh prostate tissue. The prostate epithelial cell line BPH-1 was cultured with the supernatant of the HPEC cell culture (fractioned by fast protein liquid chromatography) and the VEGF concentration was subsequently measured. HPEC were incubated with VEGF or tumor necrosis factor alpha (TNF-alpha). Afterwards, the concentration of sVEGFR-2 in the supernatant of unstimulated and stimulated HPEC was measured by ELISA. HPEC showed a typical endothelial morphology. Under cell culture conditions sVEGFR-2 binds VEGF: The measured VEGF concentration in the supernatant of BPH-1 cells was reduced when the fractions of HPEC conditioned medium with the highest sVEGFR-2 concentration were incubated with the BPH-1 cells. The sVEGFR-2 secretion of HPEC was stimulated by VEGF and TNF-alpha. For the first time we report on the secretion of sVEGFR-2 by microvascular endothelial cells of prostate origin. The secretion of sVEGFR-2 by HPEC was stimulated by VEGF and TNF-alpha. Our data suggest that sVEGFR-2 secreted by prostate endothelial cells could modify the effect of VEGF on prostate endothelial and prostate epithelial cells.

Mitochondria-mediated apoptosis by diallyl trisulfide in human prostate cancer cells is associated with generation of reactive oxygen species and regulated by Bax/Bak

Garlic constituent diallyl trisulfide (DATS) inhibits growth of cancer cells in vitro and in vivo by causing apoptosis, but the sequence of events leading to cell death is not fully understood. We now show that DATS treatment triggers mitochondria-mediated apoptosis program in human prostate cancer cells (LNCaP, LNCaP-C81, LNCaP-C4-2) irrespective of their androgen responsiveness. Interestingly, a normal prostate epithelial cell line (PrEC) is significantly more resistant to apoptosis induction by DATS compared with prostate cancer cells. The DATS-induced apoptosis in LNCaP cells correlated with the collapse of mitochondrial membrane potential, modest increase in protein level of Bak, and down-regulation of Bcl-2 and Bcl-xL protein levels. The DATS-induced apoptosis was significantly attenuated by knockdown of Bax and Bak proteins, but not by ectopic expression of either Bcl-2 or Bcl-xL. The DATS treatment caused generation of reactive oxygen species (ROS) in LNCaP cells, but not in PrEC, which was attenuated by pretreatment with antioxidant N-acetylcysteine. The N-acetylcysteine pretreatment conferred significant protection against DATS-mediated disruption of the mitochondrial membrane potential and apoptosis. In conclusion, the present study reveals that the mitochondria-mediated cell death by DATS is associated with ROS generation and regulated by Bax/Bak but independent of Bcl-2 or Bcl-xL.

Caspase-dependent apoptosis induction by guggulsterone, a constituent of Ayurvedic medicinal plant Commiphora mukul, in PC-3 human prostate cancer cells is mediated by Bax and Bak

The present study was undertaken to gain insights into the molecular mechanism of cell death (apoptosis) by guggulsterone, a constituent of Ayurvedic medicinal plant Commiphora mukul, using PC-3 human prostate cancer cells as a model. The viability of PC-3 cells, but not a normal prostate epithelial cell line (PrEC), was reduced significantly on treatment with guggulsterone in a concentration-dependent manner. Guggulsterone-mediated suppression of PC-3 cell proliferation was not due to perturbation in cell cycle progression but caused by apoptosis induction characterized by appearance of subdiploid cells and cytoplasmic histone-associated DNA fragmentation. Guggulsterone-induced apoptosis was associated with induction of multidomain proapoptotic Bcl-2 family members Bax and Bak. Interestingly, the expression of antiapoptotic proteins Bcl-2 and Bcl-xL was initially increased in guggulsterone-treated PC-3 cells but declined markedly following a 16- to 24-hour treatment with guggulsterone. Ectopic expression of Bcl-2 in PC-3 cells failed to confer significant protection against guggulsterone-induced cell death. On the other hand, SV40 immortalized mouse embryonic fibroblasts derived from Bax-Bak double knockout mice were significantly more resistant to guggulsterone-induced cell killing compared with wild-type cells. Guggulsterone treatment resulted in cleavage (activation) of caspase-9, caspase-8, and caspase-3, and guggulsterone-induced cell death was significantly attenuated in the presence of general caspase inhibitor as well as specific inhibitors of caspase-9 and caspase-8. In conclusion, the present study indicates that caspase-dependent apoptosis by guggulsterone is mediated in part by Bax and Bak.

Diallyl trisulfide-induced G(2)-M phase cell cycle arrest in human prostate cancer cells is caused by reactive oxygen species-dependent destruction and hyperphosphorylation of Cdc 25 C

Molecular mechanism of cell cycle arrest caused by diallyl trisulfide (DATS), a garlic-derived cancer chemopreventive agent, has been investigated using PC-3 and DU 145 human prostate cancer cells as a model. Treatment of PC-3 and DU 145 cells, but not a normal prostate epithelial cell line (PrEC), with growth suppressive concentrations of DATS caused enrichment of the G(2)-M fraction. The DATS-induced cell cycle arrest in PC-3 cells was associated with increased Tyr(15) phosphorylation of cyclin-dependent kinase 1 (Cdk 1) and inhibition of Cdk 1/cyclinB 1 kinase activity. The DATS-treated PC-3 and DU 145 cells also exhibited a decrease in the protein level of Cdc 25 C and an increase in its Ser(216) phosphorylation. The DATS-mediated decrease in protein level and Ser(216) phosphorylation of Cdc 25 C as well as G(2)-M phase cell cycle arrest were significantly attenuated in the presence of N-acetylcysteine implicating reactive oxygen species (ROS) in cell cycle arrest caused by DATS. ROS generation was observed in DATS-treated PC-3 and DU 145 cells. DATS treatment also caused an increase in the protein level of Cdk inhibitor p21, but DATS-induced G(2)-M phase arrest was not affected by antisense-mediated suppression of p21 protein level. In conclusion, the results of the present study indicate that DATS-induced G(2)-M phase cell cycle arrest in human prostate cancer cells is caused by ROS-mediated destruction and hyperphosphorylation of Cdc 25 C.

Expression of granulocyte colony stimulating factor receptor in human colorectal cancer

AIMS

To discover if human colorectal cancer expresses granulocyte colony stimulating factor receptor (G-CSFR) and if granulocyte colony stimulating factor (G-CSF) plays an important part in the development and progression of human colorectal cancer.

METHODS

Forty two specimens of colorectal cancer and normal colorectal mucosa were investigated, taken from the colon or rectum in group of colorectal cancer patients. Immunohistochemistry and reverse transcription polymerase chain reaction (RT-PCR) technique were used to show G-CSFR expression. The relation between expression of G-CSFR and clinical or pathological factors was analysed.

RESULTS

Immucohistochemical analyses showed that G-CSFR was expressed in the human colorectal cancer (25 of 42, 59.52%) and seemed to be up-regulated compared with the normal mucosa (14 of 42, 33.33%, p<0.001). In pronounced contrast with mostly strongly positive tumours, corresponding normal colorectal mucosa was negative or weakly positive. A significant correlation was found between G-CSFR expression and tumour stage (p = 0.001), tumour differentiation (p<0.001), but there was no significant relation between the expression of G-CSFR and the age, sex, and tumour size (p = 0.346, p = 0.686, p = 0.459). In RT-PCR, 21 of all 42 tumours had G-CSFR mRNA expression, while only 11 of 42 normal colorectal mucosa had such expression.

CONCLUSIONS

These data show that G-CSFR is commonly expressed in human colorectal cancers, thus supporting a possible role for G-CSF in colorectal cancer physiology.

Vitamin A up-regulates the expression of thrombospondin-1 and pigment epithelium-derived factor in retinal pigment epithelial cells

Vitamin A is essential for the visual system. It is metabolized in the retina and the resulting product, retinoic acid (RA), greatly affects the structure and functions of retinal pigment epithelial (RPE) cells. RPE cells produce a variety of extracellular matrix (ECM) proteins and angiogenic factors, both of which are expressed at varying levels in the normal RPE layer. In this study, we investigated the effect of all-trans-retinoic acid on the production of an ECM protein, thrombospondin-1 (TSP-1), and two angiogenic factors, pigment epithelium-derived factor (PEDF) and vascular endothelial growth factor (VEGF) by RPE cells. RA increased the release of TSP-1 and PEDF, but not that of VEGF, from human RPE cells in vitro. In vitamin A-deficient mice, the expression of TSP-1 and PEDF in the RPE layer considerably decreased compared with that of normal control mice. The vitamin A deficiency hardly affected the accumulation of VEGF in the RPE layer. These findings suggest that vitamin A modulates the structure and anti-angiogenic functions of the RPE layer partly by up-regulating the expression of the angiogenesis-related ECM protein, TSP-1, and the anti-angiogenic factor, PEDF.

Effects of androgen suppression and radiation on prostate cancer suggest a role for angiogenesis blockade

Antiandrogen therapy is an important modality in the treatment of prostate cancer. Recent research into the role of angiogenesis in tumour growth and metastasis has uncovered links between antiandrogen therapy, radiation therapy and angiogenesis, which have exciting implications for the treatment of prostate cancer. Angiogenic cytokines such as vascular endothelial growth factor (VEGF) have been identified in prostate cancer cells and tumours, and androgens appear to stimulate VEGF. This article assesses the antiangiogenic effects of hormonal therapy and assesses the role that angiogenesis may play in the observed cooperation between hormonal and radiation therapies for prostate cancer.

Transplantation of circulating endothelial progenitor cells restores endothelial function of denuded rabbit carotid arteries

BACKGROUND AND PURPOSE

Circulating endothelial progenitor cells (EPCs) play an important role in repair of injured vascular endothelium and neovascularization. The present study was designed to determine the effect of EPCs transplantation on the regeneration of endothelium and recovery of endothelial function in denuded carotid arteries.

METHODS

Isolated mononuclear cells from rabbit peripheral blood were cultured in endothelial growth medium for 7 days, yielding EPCs. A rabbit model of common carotid artery denudation by passage of a deflated balloon catheter was used to evaluate the effects of EPCs on endothelial regeneration and vasomotor function. Immediately after denudation, autologous EPCs (10(5) cells in 200 microL saline) or 200 microL saline alone (control) were administered into the lumen of injured artery.

RESULTS

Four weeks after transplantation, fluorescence-labeled colonies of EPCs were found in the vessel wall. Local transplantation of EPCs as compared with saline administration accelerated endothelialization and significantly improved endothelium-dependent relaxation when assessed 4 weeks after denudation (n=4 to 5, P<0.05). Transplantation of EPCs did not affect vasomotor function of arterial smooth muscle cells. Protein array analysis of conditioned media obtained from cultured EPCs demonstrated the ability of these cells to produce and release a number of proangiogenic cytokines.

CONCLUSIONS

We conclude that local delivery of cultured circulating EPCs into the lumen of denuded carotid arteries accelerates endothelialization and improves endothelial function. Paracrine effects of EPCs may contribute to regenerative properties of EPCs.

TNF-alpha promotes progression of peritoneal metastasis as demonstrated using a green fluorescence protein (GFP)-tagged human gastric cancer cell line

The mechanisms underlying progression of peritoneal metastasis by gastric cancer after micrometastasis formation remain unclear. In the present study, we investigated metastasis to the abdominal wall peritoneum, one of the major features of peritoneal spread, using a human gastric cancer cell line (GCIY-EGFP) tagged with the green fluorescence protein gene (GFP). This model allows sensitive, specific and sequential observation of metastasis development from the initial deposits to peritoneal carcinomatosis at the end stage. In the initial phase, GCIY-EGFP cells could form micrometastasis selectively on the omentum and mesenterium in a milky spot-dependent manner, but not on abdominal wall peritoneum lacking milky spots until the late stages. In vitro analysis using primary mesothelial cells revealed addition of TNF-alpha to decrease their stress fibers, leading to morphological change followed by exposure of the submesothelial extracellular matrix (ECM) in intercellular gaps. Such TNF-alpha pretreatment was found to enhance attachment of tumor cells to the mesothelial monolayer. When tumor cells were injected into the peritoneal cavity of TNF-alpha pretreated mice, they could metastasize to the abdominal wall peritoneum from the very early stages, resulting in accelerated accumulation of ascites than in TNF-alpha non-pretreatment controls. RT-PCR analysis revealed that tumor cells express cytokines and chemokines, including TNF-alpha. Furthermore, TNF-alpha treatment results in up-regulation of expression of monocyte chemoattractant protein-1 (MCP-1) and IL-8 by mesothelial cells and of TNF-alpha itself by inflammatory leukocytes in the peritoneal cavity. These results suggest that metastasis to the abdominal wall peritoneum occurs as a second step from the first omental metastasis in a milky spot-independent manner and that TNF-alpha derived from tumor cells, mesothelial cells and inflammatory leukocytes in the peritoneal cavity may be involved in the progression of peritoneal metastasis.

Are primary cultures realistic models of prostate cancer?

Primary cultures fill a unique niche among the repertoire of in vitro model systems available to investigate the biology of the normal and malignant human prostate. This review summarizes some of the properties of primary cultures, with special emphasis on two questions: are primary cultures from adenocarcinomas really comprised of cancer rather than normal cells, and do primary cultures faithfully retain characteristics of cells of origin?

Angiogenesis and prostate cancer tumor growth

The initiation of new blood vessels through angiogenesis is critical to tumor growth. Tumor cells release soluble angiogenic factors that induce neovascularization, without which nutrients and oxygen would not be available to allow tumors to grow more than 2-3 mm in diameter. This "angiogenic switch" or angiogenic phenotype requires an imbalance between proangiogenic and antiangiogenic factors since the formation of new blood vessels is highly regulated. This review discusses angiogenesis mediators, and the potential for manipulation of angiogenic factors as a practical cancer therapy, particularly in prostate cancer.

Androgens modulate the balance between VEGF and angiopoietin expression in prostate epithelial and smooth muscle cells

BACKGROUND

The vasculature of the prostate responds to androgens. Androgens most likely affect the vasculature indirectly by modulating the expression of angiogenic factors in the cells of the prostate. Most studies to date have examined the production of angiogenic factors by the prostate luminal epithelium. Here we examine the effects of androgen on production of three angiogenic factors, vascular endothelial growth factor (VEGF), angiopoietin-1, and angiopoietin-2, by the three major cell types in the prostate.

METHODS

The ability of androgen to modulate VEGF, angiopoietin-1, and angiopoietin-2 production in cultured mouse prostate luminal epithelial, basal epithelial, and smooth muscle cells (SMCs) was assessed by Western blot and RT-PCR.

RESULTS

The production of VEGF was modulated by androgens in both luminal epithelial and prostate SMCs but not in basal epithelial cells. However, in prostate luminal epithelial cell cultures, VEGF was predominately secreted apically, suggesting that in vivo most of the epithelium-derived VEGF is unavailable to the underlying blood vessels. In addition, prostate luminal epithelial cells produced angiopoietin-2, an angiogenesis inhibitor. In contrast, prostate SMCs produced angiopoietin-1, a positive modulator of angiogenesis. Synthesis of the angiopoietins did not respond to androgen treatment.

CONCLUSIONS

Prostate smooth muscle may play an important role in regulating vascular responses to androgen.

Thrombospondin-1, vascular endothelial growth factor and fibroblast growth factor-2 are key functional regulators of angiogenesis in the prostate

BACKGROUND

Prostate cells secrete many molecules capable of regulating angiogenesis; however, which of these actually function as essential regulators of neovascularization is not yet clear.

METHODS

Functional angiogenic mediators secreted by normal and diseased prostate cells were identified using an in vitro angiogenesis assay. These factors were quantified by immunoblot or ELISA and localized in tissue by immunohistochemistry.

RESULTS

Normal prostate epithelial cell secretions were anti-angiogenic due to inhibitory thrombospondin-1 (TSP-1) whereas this inhibitor was decreased in the pro-angiogenic secretions derived from benign prostatic hyperplasia (BPH) and cancer cells. This pro-angiogenic activity depended primarily on fibroblast growth factor-2 (FGF-2) and/or vascular endothelial growth factor (VEGF) whose secretion was increased. Immunolocalization studies confirmed that the changes detected in vitro also occurred in vivo.

CONCLUSIONS

During disease progression in the prostate, production of TSP-1, the major inhibitor, is down-regulated while that of stimulatory FGF-2 and/or VEGF rise, leading to the induction of the new vessels necessary to support tumor growth.

Interleukin-8 and human cancer biology

The aggressive nature of metastatic human cancer has been shown to be related to numerous abnormalities in growth factors and their receptors. These perturbations confer a tremendous growth advantage to the malignant cells. Interleukin-8 (IL-8), originally discovered as a chemotactic factor for leukocytes, has recently been shown to contribute to human cancer progression through its potential functions as a mitogenic, angiogenic, and motogenic factor. While it is constitutively detected in human cancer tissues and established cell lines, IL-8 expression is regulated by various tumor microenvironment factors, such as hypoxia, acidosis, nitric oxide, and cell density. Understanding the mechanisms of both inducible and constitutive IL-8 expression will be helpful in designing potential therapeutic strategies of targeting IL-8 to control tumor growth and metastasis. In this review, the role and regulation of IL-8 expression in the growth and metastasis of human cancer with a focus on human pancreatic adenocarcinoma will be discussed.

Blood vessels are regulators of growth, diagnostic markers and therapeutic targets in prostate cancer

The vasculature plays an important role in the normal and malignant prostate. Under basal conditions both glandular epithelial and stromal prostate cells produce an abundance of blood flow and angiogenesis regulating substances and the expression of these is generally increased in prostate tumors. The proportion of proliferating endothelial cells is high in the normal prostate compared to other tissues in the body. After castration effects on the vasculature, such as decreased blood flow and vascular regression, precede effects on the glandular compartment. Correspondingly, hormone induced prostate growth is characterized by early effects on the vasculature such as increased blood flow and endothelial cell proliferation, thus indicating that the vasculature may be involved in the androgenic regulation of the prostate. Prostatic intraepithelial neoplasia (PIN) and prostate cancer are associated with increased vascular density and in experimental models prostate cancer growth is apparently angiogenesis-dependent since tumor growth and progression can be inhibited by antiangiogenic treatment. Moreover, vascular density has been related to prognosis in prostate cancer patients. A better understanding of the pathways regulating angiogenesis in the normal prostate and how these pathways change during malignant transformation can hopefully lead to better prognostic markers and therapies for the large group of patients with prostate cancer. The purpose of this review is therefore to summarize the current knowledge on the role and regulation of the vasculature in the prostate and its potential clinical applications.

Pro-apoptotic and immunomodulatory activity of a mycobacterial cell wall-DNA complex towards LNCaP prostate cancer cells

BACKGROUND

We have isolated a mycobacterial cell wall-DNA complex (MCC) possessing anti-cancer activity against bladder cancer cells. The anti-cancer activity of MCC appears to be due to two effects: a direct interaction with bladder cancer cells resulting in the induction of apoptosis and an indirect effect via the stimulation of monocytes and macrophages cytokine synthesis. In this study, the direct effect of MCC towards LNCaP cancer cells was evaluated.

METHODS

Inhibition of proliferation, cell cycle arrest and induction of apoptosis were evaluated in vitro using LNCaP cells treated with MCC. The synthesis of IL-12, GM-CSF, and TNF-alpha by LNCaP cells in response to MCC was also determined. Experiments were performed to gain insight into the mechanism of action of MCC towards LNCaP cells.

RESULTS

MCC caused a dose-dependent inhibition of the proliferation of LNCaP cells that was associated with cell cycle arrest at the G0/G1 phase. MCC-induced apoptosis of LNCaP cells was consistent with a mitochondrial pathway involving mitochondrial disruption, release of cytochrome c, and an increase in Bax protein levels leading to caspase-3 and -7 activation and cleavage of poly (ADP-ribose) polymerase and nuclear mitotic apparatus protein. Surprisingly, MCC also directly induced the synthesis of IL-12 and GM-CSF, but not TNF-alpha, by LNCaP cells.

CONCLUSIONS

MCC possesses the ability to directly induce apoptosis of LNCaP cells and to trigger the synthesis of IL-12 and GM-CSF by these cells, suggesting a potential role of MCC for the treatment of prostate cancer.

Regulation of interleukin-8 expression by tumor-associated stress factors

Tumor and host cells frequently express interleukin-8 (IL-8). IL-8 has been shown to be motogenic, mitogenic, and angiogenic and to play important roles in human tumor progression. IL-8 expression can be induced by numerous stress factors present in the tumor environment, such as hypoxia, acidosis, hyperglycemia, hyperosmotic pressure, high cell density, hyperthermia, radiation, and chemotherapeutic agents. Understanding the mechanisms of IL-8 expression and regulation will be helpful in designing potential therapeutic modalities targeting IL-8 to control tumor growth and metastasis.

Primary culture of microvascular endothelial cells from human benign prostatic hyperplasia

BACKGROUND

Prostate growth seems to be influenced by paracrine factors like IL-6 originating from the microvascular endothelium. Therefore, our efforts were focused on the primary culture and behavior of microvascular endothelial cells (HPEC) derived from tissue of human benign prostatic hyperplasia (BPH). Until now, the isolation and culture of HPEC from BPH have not been reported.

METHODS

BPH tissue was cut into small cubes and gently squeezed after incubation with dispase. HPEC were cultured from the resulting cell suspension after a stepwise selection by use of superparamagnetic beads coated with antibodies against endothelial specific antigens. HPEC were characterized by flow cytometry and immunohistochemistry. gamma-Glutamyl transpeptidase activity (specific for microvascular endothelium) was measured after dissolution of the HPEC with Triton X-100. After the incubation of HPEC either with ATP, VEGF, or TNF-alpha, the release of IL-6 was measured by enzyme linked immunosorbent assay (ELISA).

RESULTS

HPEC showed a typical endothelial morphology. They were positive for von Willebrand factor, CD31, CD62E (after stimulation with TNF-alpha), alpha-actin and were negative for fibroblastic antigens and PSA. Proliferation was stimulated by vascular endothelial growth factor (VEGF). gamma-Glutamyl transpeptidase activity in HPEC was 6.3 microIU/microg protein, whereas in human umbilical vein endothelial cells (HUVEC) no gamma-glutamyl transpeptidase activity was detectable. The IL-6 secretion of HPEC was stimulated by VEGF and TNF-alpha, but not by ATP and bradykinin.

CONCLUSIONS

For the first time, the primary culture of microvascular endothelial cells from BPH tissue was successfully performed. Our results suggest that HPEC may be actively involved in prostate growth, due to the secretion of regulatory factors such as IL-6.

Profiling and verification of gene expression patterns in normal and malignant human prostate tissues by cDNA microarray analysis

cDNA microarray technology allows the "profiling" of gene expression patterns for virtually any cellular material. In this study, we applied cDNA microarray technology to profile changes in gene expression associated with human prostate tumorigenesis. RNA prepared from normal and malignant prostate tissue was examined for the expression levels of 588 human genes. Four different methods for data normalization were utilized. Of these, normalization to ACTB expression proved to be the most rigorous technique with the least probability of producing spurious results. After normalization to ACTB expression, 15 of 588 (2.6%) genes examined by array analysis were differentially expressed by a factory of 2x or more in malignant compared to normal prostate tissues. The expression patterns for 8 of 15 genes have been reported previously in prostate tissues (TGFbeta3, TGFBR3, IGFII, IGFBP2, VEGF, FGF7, ERBB3, MYC), but those of seven genes are reported here for the first time (MLH1, CYP1B1, RFC4, EPHB3, MGST1, BTEB2, MLP). These genes describe at least four metabolic and signaling pathways likely disrupted in human prostate tumorigenesis. Reverse transcriptase polymerase chain reaction (RT-PCR) and Northern blot analyses quantitated with reference to ACTB expression levels verified the trends in gene expression levels observed by array analysis for 14/15 and 8/8 genes, respectively. However, RT-PCR and Northern blot analyses accurately verified the "fold" differences in expression levels for only 6/15 (40%) and 7/8 (88%) of genes examined, respectively, demonstrating the need to better validate quantitative differences in gene expression revealed by array-based techniques.

Increased expression of the interleukin-11 receptor and evidence of STAT3 activation in prostate carcinoma

Previous investigations have shown that interleukin-6, a member of the JAK-STAT activating family of cytokines, plays an important role in prostate carcinoma. Here we demonstrate the co-expression of another member of this cytokine family, interleukin-11 (IL-11), and components of its receptor (interleukin-11 receptor; IL-11R), ie, IL-11Ralpha (involved in ligand recognition), and gp130 (involved in signal transduction) in cultured normal and malignant prostate-derived epithelial cell lines. In the DU-145 prostate carcinoma cell line, rhIL-11 stimulates a transient and dose-dependent increase in the tyrosine 705-phosphorylated, active form of STAT3 (STAT3 P-Tyr705), involved in the downstream signaling of IL-11R and other members of the gp130-dependent receptors. The ability of IL-11 to activate STAT3 in prostate-derived cells may be mechanistically important, given recent data suggesting that constitutively activated STAT3 may be associated with the malignant phenotype. In 51 human primary tissues derived from normal prostate, benign prostatic hyperplasia, and prostate carcinomas, IL-11Ralpha and gp130 were commonly expressed, with a statistically significant elevation in the expression of IL-11Ralpha in prostate carcinoma. Also, the tyrosine-phosphorylated, activated form of STAT3 was observed more prominently in the nuclei of cells residing in malignant glands compared to those in nonmalignant samples. Thus, the IL-11 receptor system is up-regulated in prostate carcinoma, and may be one part of a cytokine network that maintains STAT3 in its activated form in these tissues.

In vitro and in vivo production of vascular endothelial growth factor by chronic lymphocytic leukemia cells

Expansion of primary solid tumors and their malignant dissemination are angiogenesis-dependent. Vascular endothelial growth factor (VEGF) is the key factor playing a pivotal role in solid tumor-induced angiogenesis. Recent studies indicate that angiogenesis may also be involved in the pathogenesis of certain hemic malignancies, including B-cell chronic lymphocytic leukemia (B-CLL). Mechanisms underlying angiogenesis in B-CLL and the role of VEGF in this process are incompletely understood. In this study, it was examined whether angiogenically functional VEGF is produced by B-CLL cells. Immunohistochemical staining with antibodies against VEGF and CD34, an endothelial cell marker, demonstrated the presence of VEGF protein and abundant blood vessels in infiltrated lymphoreticular tissues. Low levels of VEGF were detected by ELISA in the culture media of unstimulated cells; this was enhanced up to 7-fold by hypoxic stimulation. SDS-PAGE and Western blot analysis of the concentrated culture media showed 2 isoforms of VEGF protein with molecular weights of 28 and 42 kd, respectively. RNA hybridization showed that these cells expressed VEGF mRNA. Reverse transcription–polymerase chain reaction, combined with nucleotide sequence analysis, revealed that the predominantly expressed isoforms were VEGF121 and VEGF165. Moreover, 3H-thymidine incorporation and an in vivo angiogenic assay demonstrated that the VEGF produced by CLL cells can induce angiogenesis by stimulating endothelial cell proliferation. In conclusion, this study shows that B-CLL cells produce VEGF and demonstrates the angiogenic effects of this growth factor, which may be relevant for the tissue phase of the disease.

In vitro and in vivo production of vascular endothelial growth factor by chronic lymphocytic leukemia cells

Expansion of primary solid tumors and their malignant dissemination are angiogenesis-dependent. Vascular endothelial growth factor (VEGF) is the key factor playing a pivotal role in solid tumor-induced angiogenesis. Recent studies indicate that angiogenesis may also be involved in the pathogenesis of certain hemic malignancies, including B-cell chronic lymphocytic leukemia (B-CLL). Mechanisms underlying angiogenesis in B-CLL and the role of VEGF in this process are incompletely understood. In this study, it was examined whether angiogenically functional VEGF is produced by B-CLL cells. Immunohistochemical staining with antibodies against VEGF and CD34, an endothelial cell marker, demonstrated the presence of VEGF protein and abundant blood vessels in infiltrated lymphoreticular tissues. Low levels of VEGF were detected by ELISA in the culture media of unstimulated cells; this was enhanced up to 7-fold by hypoxic stimulation. SDS-PAGE and Western blot analysis of the concentrated culture media showed 2 isoforms of VEGF protein with molecular weights of 28 and 42 kd, respectively. RNA hybridization showed that these cells expressed VEGF mRNA. Reverse transcription–polymerase chain reaction, combined with nucleotide sequence analysis, revealed that the predominantly expressed isoforms were VEGF121 and VEGF165. Moreover, 3H-thymidine incorporation and an in vivo angiogenic assay demonstrated that the VEGF produced by CLL cells can induce angiogenesis by stimulating endothelial cell proliferation. In conclusion, this study shows that B-CLL cells produce VEGF and demonstrates the angiogenic effects of this growth factor, which may be relevant for the tissue phase of the disease.

The expression of the ADAMs proteases in prostate cancer cell lines and their regulation by dihydrotestosterone

The ADAMs are a multi-functional gene family, some of which have been shown to play a role in diverse biological processes such as fertilization, myogenesis, neurogenesis and the activation of growth factors/immune regulators such as TNF-alpha. So-named because they possess both A Disintegrin And Metalloprotease domain, the ADAMs have potential implications for the metastasis of human tumour cells via cell adhesion and protease activities. However, no studies have yet comprehensively examined the expression or regulation of ADAMs in solid tumours. Therefore, the aim of this study was to examine the expression of the ADAMs in human prostate cancer cell lines and to examine their possible regulation by androgen, a primary hormonal regulator of prostate cancer cell proliferation and metastasis. Applying RT-PCR, ADAM-9, -10, -11, -15 and -17 mRNA expression was found in the androgen-dependent prostate cancer cell lines, LNCaP and ALVA-41 and the androgen-independent cell lines, DU-145 and PC-3. Northern blotting of LNCaP cell total RNA revealed transcripts for ADAM-9 (3.8 kb), ADAM-10 (4.4, 3.2 and 0.54 kb), ADAM-15 (3 kb) and ADAM-17 (4 and 2.6 kb). ADAM-11 transcript was not detected by Northern blotting possibly due to low levels of ADAM-11 mRNA expression. This is the first report of ADAM expression in prostate cancer cell lines. Since androgens are implicated in prostate cancer cell growth and maintenance, the regulation of ADAMs by dihydrotestosterone (DHT) was investigated in the androgen-dependent cell line LNCaP. It was shown by quantitative RT-PCR using continuous fluorescence monitoring that ADAM-10 mRNA expression was regulated in a bell shaped, dose-dependent manner by DHT. Maximum stimulation was observed at 1.0 nM DHT (5-fold significant increase). For ADAM-9 mRNA, a significant upregulation was found at 1.0 and 10 nM (1.5-1.7-fold increase). In contrast, ADAM-17 mRNA, was significantly inhibited at 0.1 and 1.0 nM (1.7-fold decrease). This is the first report, to our knowledge, illustrating hormonal regulation of ADAM mRNA. The novel data described here also provide a strong stimulus to the development of specific quantitative and functional assays for particular ADAMs. These assays, which are not yet available, are required to enable subsequent investigation, both in vitro and in vivo, of the specific roles of each ADAM in prostate cancer cell proliferation, cell motility and invasion.

Vascular endothelial growth factor content in metastasizing and nonmetastasizing Dunning prostatic adenocarcinoma

BACKGROUND

Tumor angiogenesis is important in progressive tumor growth and metastasis. In the normal rat prostate and in androgen-sensitive prostate tumors androgen ablation causes an involution of the vasculature and a decrease in the vascular endothelial growth factor (VEGF) levels before regression of the prostate gland. To examine whether angiogenesis and metastasis are regulated by VEGF in androgen-insensitive and metastasizing prostate tumors, five Dunning rat prostate cancer sublines were tested; the androgen-sensitive, nonmetastasizing R3327 PAP, and the androgen-insensitive, low metastasizing AT-1, and the three androgen-insensitive, metastasizing AT-2, AT-3, and MatLyLu Dunning prostatic adenocarcinomas.

METHODS

VEGF levels were quantified in the rat dorsolateral prostate and in the five Dunning sublines using competitive RT-PCR, Western blot, and Elisa. Vascular density was determined by factor VIII staining.

RESULTS

VEGF mRNA was increased in all tumors compared with normal prostates. The two metastatic sublines AT-3 and MatLyLu and the nonmetastatic subline AT-1 showed the highest VEGF mRNA expression. VEGF protein levels in the prostate gland showed increased expression in the metastatic sublines, AT-2, AT-3, and MatLyLu, compared with the nonmetastatic AT-1 subline and the ventral prostate. VEGF proteins in serum were highest in the metastatic AT-3 subline. The vessel density was highest in the two highly metastatic sublines AT-3 and MatLyLu.

CONCLUSIONS

Our results suggest that VEGF levels are associated with microvessel density and the previously established metastatic pattern of these rat prostate tumor systems.