Transforming growth factor beta as a clinical biomarker for prostate cancer

The TβRI promotes migration and metastasis through thrombospondin 1 and ITGAV in prostate cancer cells

TGFβ potently modifies the extracellular matrix (ECM), which is thought to favor tumor cell invasion. However, the mechanism whereby the cancer cells employ the ECM proteins to facilitate their motility is largely unknown. In this study we used RNA-seq and proteomic analysis to examine the proteins secreted by castration-resistant prostate cancer (CRPC) cells upon TGFβ treatment and found that thrombospondin 1 (THBS1) was observed to be one of the predominant proteins. The CRISPR Cas9, or siRNA techniques was used to downregulate TGFβ type I receptor (TβRI) to interfere with TGFβ signaling in various cancer cells in vitro. The interaction of ECM proteins with the TβRI in the migratory prostate cancer cells in response to TGFβ1 was demonstrated by several different techniques to reveal that THBS1 mediates cell migration by interacting with integrin subunit alpha V (ITGAV) and TβRI. Deletion of TβRI or THBS1 in cancer cells prevented their migration and invasion. THBS1 belongs to a group of tumorigenic ECM proteins induced via TGFβ signaling in CRPC cells, and high expression of THBS1 in human prostate cancer tissues correlated with the degree of malignancy. TGFβ-induced production of THBS1 through TβRI facilitates the invasion and metastasis of CRPC cells as shown in vivo xenograft animal experiments.

Targeting Transforming Growth Factor-Beta1 (TGF-β1) Inhibits Tumorigenesis of Anaplastic Thyroid Carcinoma Cells Through ERK1/2-NFκkB-PUMA Signaling

BACKGROUND The transforming growth factor-beta (TGF-β) signaling pathway plays a critical role in promoting tumor growth. TGF-β1was found to be overexpressed in anaplastic thyroid cancer (ATC). We therefore tested our hypothesis that targeting TGF-β1 inhibits tumorigenesis of ATC cells. MATERIAL AND METHODS Effects of TGF-β1 stimulation or TGF-β1 inhibition by small interfering RNA (TGF-β1siRNA) on proliferation, colony formation, and apoptosis in 8505C cells in vitro was detected using siRNAs and inhibitors to examine the TGF-β1 signaling pathway. A subcutaneously implanted tumor model of 8505C cells in nude mice was used to assess the effects of TGF-β1 inhibition on tumorigenesis development. RESULTS TGF-β1siRNAs decreased proliferation and colony formation, and increased apoptosis in 8505C cells in vitro and inhibited tumor growth in vivo. TGF-β1siRNA inhibited phosphorylation ERK1/2 (pERK1/2) and increased p65-dependant PUMA mRNA and protein expression. Knockdown of p65 or PUMA by siRNA reduced TGF-β1siRNA-induced apoptosis, as well as caspase-3 and PARP activation. Upregulation of p65 or PUMA expression by TGF-β1siRNA requires pERK1/2 inhibition. TGF-β1 shRNA inhibited tumor growth in vivo. CONCLUSIONS Therapies targeting the TGF-β1 pathway may be more effective to prevent primary tumor formation. The ability of this therapy to decrease tumorigenesis may be related to ERK1/2/NF-κB/PUMA signaling.

Prostate cancer markers: An update

As the most common noncutaneous malignancy in American men, prostate cancer currently accounts for 29% of all diagnosed cancers, and ranks second as the cause of cancer fatality in American men. Prostatic cancer is rarely symptomatic early in its course and therefore disease presentation often implies local extension or even metastatic disease. Thus, it is extremely critical to detect and diagnose prostate cancer in its earliest stages, often prior to the presentation of symptoms. Three of the most common techniques used to detect prostate cancer are the digital rectal exam, the transrectal ultrasound, and the use of biomarkers. This review presents an update regarding the field of prostate cancer biomarkers and comments on future biomarkers. Although there is not a lack of research in the field of prostate cancer biomarkers, the discovery of a novel biomarker that may have the advantage of being more specific and effective warrants future scientific inquiry.

Biomarkers for evaluation of prostate cancer prognosis

Prostate cancer, with a lifetime prevalence of one in six men, is the second cause of malignancy-related death and the most prevalent cancer in men in many countries. Nowadays, prostate cancer diagnosis is often based on the use of biomarkers, especially prostate-specific antigen (PSA) which can result in enhanced detection at earlier stage and decreasing in the number of metastatic patients. However, because of the low specificity of PSA, unnecessary biopsies and mistaken diagnoses frequently occur. Prostate cancer has various features so prognosis following diagnosis is greatly variable. There is a requirement for new prognostic biomarkers, particularly to differentiate between inactive and aggressive forms of disease, to improve clinical management of prostate cancer. Research continues into finding additional markers that may allow this goal to be attained. We here selected a group of candidate biomarkers including PSA, PSA velocity, percentage free PSA, TGFβ1, AMACR, chromogranin A, IL-6, IGFBPs, PSCA, biomarkers related to cell cycle regulation, apoptosis, PTEN, androgen receptor, cellular adhesion and angiogenesis, and also prognostic biomarkers with Genomic tests for discussion. This provides an outline of biomarkers that are presently of prognostic interest in prostate cancer investigation.

Crosstalk between epithelial-mesenchymal transition and castration resistance mediated by Twist1/AR signaling in prostate cancer

Although invasive and metastatic progression via the epithelial-mesenchymal transition (EMT) and acquisition of resistance to castration are both critical steps in prostate cancer, the molecular mechanism of this interaction remains unclear. In this study, we aimed to elucidate the interaction of signaling between castration resistance and EMT, and to apply this information to the development of a novel therapeutic concept using transforming growth factor-β (TGF-β) inhibitor SB525334 combined with androgen-deprivation therapy against prostate cancer using an in vivo model. This study revealed that an EMT inducer (TGF-β) induced full-length androgen receptor (AR) and AR variant expression. In addition, a highly invasive clone showed augmented full-length AR and AR variant expression as well as acquisition of castration resistance. Conversely, full-length AR and AR as well as Twist1 and mesenchymal molecules variant expression were up-regulated in castration-resistant LNCaP xenograft. Finally, TGF-β inhibitor suppressed Twist1 and AR expression as well as prostate cancer growth combined with castration. Taken together, these results demonstrate that Twist1/AR signaling was augmented in castration resistant as well as mesenchymal-phenotype prostate cancer, indicating the molecular mechanism of mutual and functional crosstalk between EMT and castration resistance, which may play a crucial role in prostate carcinogenesis and progression.

Paracrine interactions between LNCaP prostate cancer cells and bioengineered bone in 3D in vitro culture reflect molecular changes during bone metastasis

As microenvironmental factors such as three-dimensionality and cell-matrix interactions are increasingly being acknowledged by cancer biologists, more complex 3D in vitro models are being developed to study tumorigenesis and cancer progression. To better understand the pathophysiology of bone metastasis, we have established and validated a 3D indirect co-culture model to investigate the paracrine interactions between prostate cancer (PCa) cells and human osteoblasts. Co-culture of the human PCa, LNCaP cells embedded within polyethylene glycol hydrogels with human osteoblasts in the form of a tissue engineered bone construct (TEB), resulted in reduced proliferation of LNCaP cells. LNCaP cells in both monoculture and co-culture were responsive to the androgen analog, R1881, as indicated by an increase in the expression (mRNA and/or protein induction) of androgen-regulated genes including prostate specific antigen and fatty acid synthase. Microarray gene expression analysis further revealed an up-regulation of bone markers and other genes associated with skeletal and vasculature development and a significant activation of transforming growth factor β1 downstream genes in LNCaP cells after co-culture with TEB. LNCaP cells co-cultured with TEB also unexpectedly showed similar changes in classical androgen-responsive genes under androgen-deprived conditions not seen in LNCaP monocultures. The molecular changes of LNCaP cells after co-culturing with TEBs suggest that osteoblasts exert a paracrine effect that may promote osteomimicry and modulate the expression of androgen-responsive genes in LNCaP cells. Taken together, we have presented a novel 3D in vitro model that allows the study of cellular and molecular changes occurring in PCa cells and osteoblasts that are relevant to metastatic colonization of bone. This unique in vitro model could also facilitate cancer biologists to dissect specific biological hypotheses via extensive genomic or proteomic assessments to further our understanding of the PCa-bone crosstalk.

Redox-mediated and ionizing-radiation-induced inflammatory mediators in prostate cancer development and treatment

SIGNIFICANCE

Radiation therapy is widely used for treatment of prostate cancer. Radiation can directly damage biologically important molecules; however, most effects of radiation-mediated cell killing are derived from the generated free radicals that alter cellular redox status. Multiple proinflammatory mediators can also influence redox status in irradiated cells and the surrounding microenvironment, thereby affecting prostate cancer progression and radiotherapy efficiency.

RECENT ADVANCES

Ionizing radiation (IR)-generated oxidative stress can regulate and be regulated by the production of proinflammatory mediators. Depending on the type and stage of the prostate cancer cells, these proinflammatory mediators may lead to different biological consequences ranging from cell death to development of radioresistance.

CRITICAL ISSUES

Tumors are heterogeneous and dynamic communication occurs between stromal and prostate cancer cells, and complicated redox-regulated mechanisms exist in the tumor microenvironment. Thus, antioxidant and anti-inflammatory strategies should be carefully evaluated for each patient at different stages of the disease to maximize therapeutic benefits while minimizing unintended side effects.

FUTURE DIRECTIONS

Compared with normal cells, tumor cells are usually under higher oxidative stress and secrete more proinflammatory mediators. Thus, redox status is often less adaptive in tumor cells than in their normal counterparts. This difference can be exploited in a search for new cancer therapeutics and treatment regimes that selectively activate cell death pathways in tumor cells with minimal unintended consequences in terms of chemo- and radio-resistance in tumor cells and toxicity in normal tissues.

The additional value of TGFβ1 and IL-7 to predict the course of prostate cancer progression

Background

Given the fact that prostate cancer incidence will increase in the coming years, new prognostic biomarkers are needed with regard to the biological aggressiveness of the prostate cancer diagnosed. Since cytokines have been associated with the biology of cancer and its prognosis, we determined whether transforming growth factor beta 1 (TGFβ1), interleukin-7 (IL-7) receptor and IL-7 levels add additional prognostic information with regard to prostate cancer-specific survival.

Materials and methods

Retrospective survival analysis of forty-four prostate cancer patients, that underwent radical prostatectomy, was performed (1989–2001). Age, Gleason score and pre-treatment PSA levels were collected. IL-7, IL-7 receptor and TGFβ1 levels in prostate cancer tissue were determined by quantitative real-time RT-PCR and their additional prognostic value analyzed with regard to prostate cancer survival. Hazard ratios and their confidence intervals were estimated, and Akaike’s information criterion was calculated for model comparison.

Results

The predictive ability of a model for prostate cancer survival more than doubled when TGFβ1 and IL-7 were added to a model containing only the Gleason score and pre-treatment PSA (AIC: 18.1 and AIC: 6.5, respectively).

Conclusion

IL-7 and TGFβ1 are promising markers to indicate those at risk for poor prostate cancer survival. This additional information may be of interest with regard to the biological aggressiveness of the diagnosed prostate cancer, especially for those patients screened for prostate cancer and their considered therapy.

Risk of developing prostate cancer in the future: overview of prognostic biomarkers

In many disease states, the use of biomarkers is a standard method of determining both the presence and the risk of the future development of disease. For several years, total prostate-specific antigen (PSA) levels have been the standard measure for the diagnosis of prostate cancer (PCa) and other prostatic diseases. However, recent data have indicated that PSA can also be used to determine the risk of developing PCa in the future. This evolving use of PSA is supported by clinical trial data from the Baltimore Longitudinal Study of Aging, the European Randomized Study of Screening for Prostate Cancer, and the Malmö Preventive Medicine Study. Data from the European Randomized Study of Screening for Prostate Cancer have demonstrated that men with a PSA level of > or =1.5 ng/mL are at a significantly elevated risk of developing PCa compared with patients with a PSA level <1.5 ng/mL. The Malmö study showed that the PSA level could independently the predict cancer risk as far as 25-30 years into the future. Secondary nonserum risk factors (eg, age, family history, ethnicity) can also offer predictive value for determining the risk of developing future disease. Furthermore, recent investigations of novel biomarkers have yielded promising PCa prognostic candidates, including the PCa gene 3 and early PCa antigen 2. However, PSA remains the most reliable measure in assessing the risk of developing PCa.

Sulforaphane enhances the therapeutic potential of TRAIL in prostate cancer orthotopic model through regulation of apoptosis, metastasis, and angiogenesis

PURPOSE

The purpose of this study was to examine the molecular mechanisms by which sulforaphane enhances the therapeutic potential of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) in prostate cancer.

EXPERIMENTAL DESIGN

Cell viability and apoptosis assays were done by XTT and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling assay, respectively. Tumor-bearing mice were treated with vehicle, sulforaphane, TRAIL, and sulforaphane plus TRAIL. Markers of apoptosis, angiogenesis, and metastasis were measured by immunohistochemistry.

RESULTS

Sulforaphane enhanced the therapeutic potential of TRAIL in PC-3 cells and sensitized TRAIL-resistant LNCaP cells. Sulforaphane-induced apoptosis in PC-3 cells correlated with the generation of intracellular reactive oxygen species (ROS), collapse of mitochondrial membrane potential, activation of caspase-3 and caspase-9, and up-regulation of DR4 and DR5. Sulforaphane induced the expression of Bax, Bak, Bim, and Noxa and inhibited the expression of Bcl-2, Bcl-X(L), and Mcl-1. The quenching of ROS generation with antioxidant N-acetyl-L-cysteine conferred significant protection against sulforaphane-induced ROS generation, mitochondrial membrane potential disruption, caspase-3 activation, and apoptosis. Sulforaphane inhibited growth of orthotopically implanted PC-3 tumors by inducing apoptosis and inhibiting proliferation and also enhanced the antitumor activity of TRAIL. Sulforaphane up-regulated the expressions of TRAIL-R1/DR4, TRAIL-R2/DR5, Bax and Bak and inhibited the activation of nuclear factor-kappaB P13K/AKT and MEK/ERK pathways in tumor tissues. The combination of sulforaphane and TRAIL was more effective in inhibiting markers of angiogenesis and metastasis and activating FOXO3a transcription factor than single agent alone.

CONCLUSIONS

The ability of sulforaphane to inhibit tumor growth, metastasis, and angiogenesis and to enhance the therapeutic potential of TRAIL suggests that sulforaphane alone or in combination with TRAIL can be used for the management of prostate cancer.

Regulation of TGF-beta1 gene transcription in human prostate cancer cells by nitric oxide

BACKGROUND

Overexpression of transforming growth factor (TGF)-beta1 is associated with advanced prostate cancer. Our previous studies showed an inverse correlation between the expressions of TGF-beta1 and inducible nitric oxide synthase (iNOS) in prostatic tumors in mice. The purpose of this study was to investigate regulation of TGF-beta1 expression in human prostate cancer cells by nitric oxide (NO).

METHODS

Expression of TGF-beta1 in the three well-characterized lines of human prostate cancer cells (PC-3MM2, LNCaP, and DU145) was determined by using the enzyme-linked immunoabsorbance assay (ELISA), real-time reverse-transcriptase PCR (RT-PCR), nuclear run-on, and promoter activity analyses.

RESULTS

Expression of both TGF-beta1 protein and mRNA was inhibited in both dose- and time-dependent manners by NO donors sodium nitroprusside (SNP), S-nitroso-N-acetylpenicilamine (SNAP), S-nitrosoglutathione (GSNO), and (+/-)-(E)-methyl-2-[(E)-hydroxyimino]-5-nitro-6-methoxy-3-hexeneamide (NOR-1) and by transfection of iNOS. The inhibitory effects of SNP and iNOS on TGF-beta1 expression were reduced in cells treated with NO scavengers N-dithiocarboxysarcosine (DTCS), 2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (PTIO), and hemoglobin, or with the iNOS inhibitor N-methyl-arginine (NMA). SNP downregulated the in vitro transcription of TGF-beta1 mRNA, inhibited TGF-beta1 promoter activity, but had no significant effects on TGF-beta1 mRNA stability.

CONCLUSION

These results show that NO downregulates TGF-beta1 expression in prostate cancer cells at transcription level by suppressing the de novo synthesis of TGF-beta1 mRNA.

New circulating biomarkers for prostate cancer

The introduction of prostate-specific antigen (PSA) revolutionized prostate cancer (PCa) screening and ushered the PSA era. However, its use as a screening tool remains controversial and changes in the epidemiology of PCa have strongly limited its prognostic role. Therefore, we need novel approaches to improve our ability to detect PCa and foretell the course of the disease. To improve the specificity of total PSA, several approaches based on PSA derivatives have been investigated such as age-specific values, PSA density (PSAD), PSAD of the transition zone, PSA velocity and assessment of various isoforms of PSA. With recent advances in biotechnology such as high-throughput molecular analyses, many potential blood biomarkers have been identified and are currently under investigation. Given the plethora of candidate PCa biomarkers, we have chosen to discuss a select group of candidate blood-based biomarkers including human glandular kallikrein, early prostate cancer antigens, insulin-like growth factor-I (IGF-I) and its binding proteins (IGFBP-2 and IGFBP-3), urokinase plasminogen activation system, transforming growth factor-beta1, interleukin-6, chromogranin A, prostate secretory protein, prostate-specific membrane antigen, PCa-specific autoantibodies and alpha-methylacyl-CoA racemase. While these and other markers have shown promise in early phase studies, no single biomarker is likely to have the appropriate degree of certainty to dictate treatment decisions. Consequently, the future of cancer prognosis may rely on small panels of markers that can accurately predict PCa presence, stage, metastasis, and serve as prognosticators, targets and/or surrogate end points of disease progression and response to therapy.

TGF-beta insensitive dendritic cells: an efficient vaccine for murine prostate cancer

Dendritic cells (DCs) are highly potent initiators of the immune response, but DC effector functions are often inhibited by immunosuppressants such as transforming growth factor beta (TGF-beta). The present study was conducted to develop a treatment strategy for prostate cancer using a TGF-beta-insensitive DC vaccine. Tumor lysate-pulsed DCs were rendered TGF-beta insensitive by dominant-negative TGF-beta type II receptor (TbetaRIIDN), leading to the blockade of TGF-beta signals to members of the Smad family, which are the principal cytoplasmic intermediates involved in the transduction of signals from TGF-beta receptors to the nucleus. Expression of TbetaRIIDN did not affect the phenotype of transduced DCs. Phosphorylated Smad-2 was undetectable and expression of surface co-stimulatory molecules (CD80/CD86) were upregulated in TbetaRIIDN DCs after antigen and TGF-beta1 stimulation. Vaccination of C57BL/6 tumor-bearing mice with the TbetaRIIDN DC vaccine induced potent tumor-specific cytotoxic T lymphocyte responses against TRAMP-C2 tumors, increased serum IFN-gamma and IL-12 level, inhibited tumor growth and increased mouse survival. Furthermore, complete tumor regression occurred in two vaccinated mice. These results demonstrate that blocking TGF-beta signals in DC enhances the efficacy of DC-based vaccines.

Molecular markers of prostate cancer

Although prostate-specific antigen (PSA) has evolved as a very useful tool for detection of prostate cancer, there remains an urgent need for more accurate biomarkers to diagnose prostate cancer and predict cancer-related outcomes. Recent advances in the study of proteomics and high throughput techniques have led to the discovery of many potential biomarkers for prostate cancer. This article briefly reviews the current status of PSA testing and discusses several candidate protein biomarkers for prostate cancer, as well as highlighting some recent proteomic discoveries with the potential to supplement or even replace PSA for the diagnosis and prognosis of prostate cancer.

Blockade of transforming growth factor-beta signaling suppresses progression of androgen-independent human prostate cancer in nude mice

We investigated the role of transforming growth factor-beta (TGF-beta) signaling in the growth and metastasis of PC-3MM2 human prostate cancer cells. Highly metastatic PC-3MM2 human prostate cancer cells were engineered to constitutively overexpress a dominant-negative type II TGF-beta receptor (DNR). Transfection of DNR had minimal direct effects on cell growth and attenuated TGF-beta-induced cell growth inhibition and TGF-beta1 production. There were no discernable differences in tumorigenicity (tumor incidence) among PC-3MM2 variants when the cells were implanted into the prostates of nude mice. Growth rate and metastatic incidence of DNR-engineered PC-3MM2 cells, however, were significantly reduced. Most cells in the control tumors were positively stained by an antibody to proliferation cell nuclear antigen and very few cells were stained by terminal deoxynucleotidyl transferase-mediated nick-end labeling (TUNEL). In sharp contrast, tumors formed by PC-3MM2-DNR cells contained fewer proliferation cell nuclear antigen-positive cells and many more TUNEL-positive cells. Staining with antibody against CD31 showed that control tumors contained more blood vessels than PC-3MM2-DNR tumors. Expression of interleukin-8 (IL-8) in tumors formed by PC-3MM2 cells was significantly reduced as revealed by both Northern blotting and ELISA. Finally, transfection of antisense IL-8 cDNA significantly reduced IL-8 production by PC-3MM2 cells and antisense IL-8-transfected PC-3MM2 cells grew slower in comparison with parental and control vector-transfected cells. Taken together, our data suggest that TGF-beta signaling, by regulating IL-8 expression in tumor cells and hence tumor angiogenesis, is critical for progressive growth of PC-3MM2 cells in the prostate of nude mice.

Transforming growth factor beta and prostate cancer

The TGF-beta superfamily is the most versatile considering the ability of its members to regulate proliferation, growth arrest, differentiation, and apoptosis of prostatic stromal and epithelial cells as well as the formation of osteoblastic metastases. TGF-beta mediated action in prostate cells follows a complex signaling pathway from binding and phosphorylation of receptor type II to the TbetaRI kinase to Smad activation, resulting in ligand-induced transcription. TGF-beta as an indirect tumor suppressor, its role of regulating tumor induction, as well as tumor suppression depending on the tissue microenvironment merits further exploration. The rationale for targeting growth factors and their receptors for therapeutic intervention is based upon the fact that these proteins represent the most proximate component of the signal transduction cascade. The alternate targeting of intracellular effectors in the signal transduction may be thwarted by cross talk between signaling pathways (such as the Smads in a dynamic interplay with the androgen receptor). TGF-beta within the context of its well-documented apoptosis regulatory actions in the prostate and the significance its key receptor TbetaRII as a potential tumor suppressor, provides a highly attractive candidate for such targeting with high clinical significance for the treatment and diagnosis of prostate cancer.

A Gain of Function TGFB1 Polymorphism May Be Associated With Late Stage Prostate Cancer

Transforming growth factor β (TGFβ) is known to exert both positive and negative effects on different stages of tumor formation. Of the TGFβisoforms, TGFβ1 is highly expressed in prostate cancer and leads to tumor promotion and metastasis. Increased expression of TGFβ1 is associated with more aggressive tumors and poor prognosis. Several polymorphisms in TGFB1 have been identified, and two variants in strong linkage disequilibrium, C−509T and T+29C, show increased serum levels. Because of the potential role of TGFB1 variants in prostate cancer and progression, we hypothesized that these two TGFB1 variants would be associated with prostate cancer risk, particularly later, more aggressive stage tumors. To test this, we conducted a nested case-control study of 492 men diagnosed with prostate cancer from the Physicians Health Study and 492 age-matched controls. In this study, cases who were homozygous for the T allele at position −509 had a 2.4-fold increased risk of more advanced stage of prostate cancer [95% confidence interval (95% CI) 1.03–5.43; P = 0.04]. The T allele frequencies in cases and controls were 32.7% and 31.4%, respectively. The same polymorphism showed a 1.23 nonsignificant odds ratio (OR) for overall prostate cancer risk (95% CI 0.80–1.87). Cases who were homozygous for the C allele at position +29 did not show any significant increase in risk for either total prostate cancer (OR 1.19, 95% CI 0.82–1.74) or advanced stage prostate cancer (OR 1.33, 95% CI 0.66–2.68). The C allele frequency in cases and controls were 39.9% and 38.5%, respectively. Our data suggest that the TGFB1 C−509T variant that affects expression of TGFβ1 may play a role in advanced stage prostate cancer.

Preferential production of latent transforming growth factor ?-2 by primary prostatic epithelial cells and its activation by prostate-specific antigen

Three mammalian isoforms of transforming growth factor-beta (TGFbeta) are known, TGFbeta1, 2, and 3, that have non-overlapping functions during development. However, their specific roles in cancers such as prostate cancer are less clear. Here we show that primary cultures of prostatic epithelial cells preferentially produce and activate the latent TGFbeta2 isoform. Paired cultures of normal and malignant prostate cells from prostate cancer patients produced predominantly the TGFbeta2 isoform, with 30- to 70-fold less TGFbeta1. By mono-Q ion exchange chromatography, three major peaks of latent TGFbeta2 activity were observed corresponding to the known small latent TGFbeta2 complex, the known large latent TGFbeta2 complex and a novel eluting peak of latent TGFbeta2. Although prostate cells are known to activate latent TGFbeta, the mechanism for activation is currently unclear. We investigated whether prostate specific antigen (PSA), a serine protease used as a clinical marker for prostate cancer, could play a role in the activation of latent TGFbeta. Unlike plasmin, a known activator of both latent TGFbeta1 and 2, PSA specifically activated the recombinant small latent form of TGFbeta2, but not TGFbeta1. Prostate epithelial cells, therefore, preferentially produce the TGFbeta2 isoform and PSA, a protease produced by the prostate, specifically targets the activation of this TGFbeta isoform. PSA-mediated activation of latent TGFbeta2 may be an important mechanism for autocrine TGFbeta regulation in the prostate and may potentially contribute to the formation of osteoblastic lesions in bone metastatic prostate cancer.

Human prostate cancer risk factors

Prostate cancer has the highest prevalence of any nonskin cancer in the human body, with similar likelihood of neoplastic foci found within the prostates of men around the world regardless of diet, occupation, lifestyle, or other factors. Essentially all men with circulating androgens will develop microscopic prostate cancer if they live long enough. This review is a contemporary and comprehensive, literature-based analysis of the putative risk factors for human prostate cancer, and the results were presented at a multidisciplinary consensus conference held in Crystal City, Virginia, in the fall of 2002. The objectives were to evaluate known environmental factors and mechanisms of prostatic carcinogenesis and to identify existing data gaps and future research needs. The review is divided into four sections, including 1) epidemiology (endogenous factors [family history, hormones, race, aging and oxidative stress] and exogenous factors [diet, environmental agents, occupation and other factors, including lifestyle factors]); 2) animal and cell culture models for prediction of human risk (rodent models, transgenic models, mouse reconstitution models, severe combined immunodeficiency syndrome mouse models, canine models, xenograft models, and cell culture models); 3) biomarkers in prostate cancer, most of which have been tested only as predictive factors for patient outcome after treatment rather than as risk factors; and 4) genotoxic and nongenotoxic mechanisms of carcinogenesis. The authors conclude that most of the data regarding risk relies, of necessity, on epidemiologic studies, but animal and cell culture models offer promise in confirming some important findings. The current understanding of biomarkers of disease and risk factors is limited. An understanding of the risk factors for prostate cancer has practical importance for public health research and policy, genetic and nutritional education and chemoprevention, and prevention strategies.

Molecular markers to identify patients at risk for recurrence after primary treatment for prostate cancer

Accurate prognostication is a prerequisite for accurate therapeutics and management of prostate cancer because indolent tumors may require no intervention, whereas aggressive tumors lead to patient mortality. There is a critical need to define these subgroups of patients with prostate cancer differing in clinical outcome. Prognostic nomograms based on clinical data provide useful predictions of clinical states and outcomes, but they need further refinements to improve accuracy and universality. Genomic and proteomic analyses have provided many novel markers that may help define prognostic parameters based on the underlying biology of prostate cancer progression at the molecular level. These molecular markers are likely to augment traditional prognostic modalities by providing a set of molecularly defined and quantifiable variables. Encompassing the genome, transcriptome, and proteome of prostate cancer will likely provide "molecular signatures" that will bridge prognostication, prediction, and treatment in a single continuum.

Biochemical staging of prostate cancer

PSA continues to be one of the most effective and widely used cancer screening tools available. Its popularity in prostate cancer screening, however, has eroded its usefulness in the staging of this disease. As more men are screened every year on a routine basis with DRE and PSA, the average PSA at diagnosis has drifted down to well below 10 ng/mL in many centers, including ours. This trend is likely to accelerate, as a PSA cut off for prompting biopsy of the prostate of 2.5 ng/mL gains more widespread acceptance. The recent realization that, at these levels, serum PSA is more reflective of the presence of BPH than of the extent of cancer and, therefore, does not provide additional staging information, has renewed the search for new biochemical markers that are capable of predicting prostate cancer stage and prognosis. Because of the heterogeneity of this disease, it is unlikely that a single biochemical marker that is capable of accurately staging all prostate cancer patients will be found. For this reason, nomograms that are capable of integrating various parameters to predict stage and prognosis will remain indispensable. As new biochemical markers that provide independent predictive information about stage or prognosis are identified, they can be incorporated into currently available nomograms. Of the biochemical markers discussed in this article, IL-6sR and TGF-beta1 are the most promising. By incorporating them into a preoperative nomogram designed to predict PSA recurrence, we found that they improved the ability to predict biochemical recurrence by a statistically and clinically significant margin. The ability to stage prostate cancer and predict response to therapy has improved dramatically over the last 3 decades. Nevertheless, there is still a need for new biochemical markers that will improve the ability to predict an individual patient's stage and response to therapy. Incorporating these new markers into nomograms will enhance the ability to provide optimal care for each prostate cancer patient.

Urinary transforming growth factor-beta1 levels correlate with bladder outlet obstruction

BACKGROUND

Urinary transforming growth factor-beta1 (TGF-beta1) levels have been shown to correlate with elevated intrapelvic pressure associated with ureteropelvic junction obstruction. Other studies have evaluated urinary TGF-beta1 levels in prostate cancer. This study tests the hypothesis that urinary TGF-beta1 levels might correlate with objective measures of bladder outlet obstruction (BOO).

METHODS

Twenty-three men (age: 46-85 years) with lower urinary tract symptoms underwent urodynamic studies consisting of non-invasive uroflowmetry, cystometrogram and voiding pressure flow studies. Patients were classified as obstructed (n = 17) or not obstructed (n = 6) based on Abrams-Griffith nomograms. Urinary TGF-beta1 was extracted from an aliquot of urine obtained at the time of bladder catheterization for urodynamic studies. Urinary TGF-beta1 levels were then determined by enzyme-linked immunosorbent assay (ELISA).

RESULTS

There was a strong correlation between urinary TGF-beta1 levels and the presence of obstruction by Abrams-Griffith nomogram criteria (P = 0.025). Urinary TGF-beta1 levels were significantly higher in men with obstruction (0.039 +/- 0.011 pg/mL) than in men without obstruction (0.029 +/- 0.009 pg/mL; P = 0.036).

CONCLUSION

Urinary TGF-beta1 levels correlate with objective measures of BOO. Further study is needed to test the utility of urinary TGF-beta1 as a non-invasive diagnostic tool for BOO.

Preoperative plasma levels of transforming growth factor beta(1) (TGF-beta(1)) strongly predict progression in patients undergoing radical prostatectomy

PURPOSE

Elevated local and circulating levels of transforming growth factor beta(1) (TGF-beta(1)) have been associated with prostate cancer invasion and metastasis. We tested the hypothesis that preoperative plasma TGF-beta(1) levels would independently predict cancer stage and prognosis in patients who undergo radical prostatectomy.

PATIENTS AND METHODS

The study group consisted of 120 consecutive patients who underwent radical prostatectomy for clinically localized prostate cancer (median follow-up, 53.8 months). Preoperative plasma levels of TGF-beta(1) were measured and correlated with pathologic parameters and clinical outcomes. TGF-beta(1) levels also were measured in 44 healthy men without cancer, in 19 men with prostate cancer metastatic to regional lymph nodes, and in 10 men with prostate cancer metastatic to bone.

RESULTS

Plasma TGF-beta(1) levels in patients with lymph node metastases (14.2 +/- 2.6 ng/mL) and bone metastases (15.5 +/- 2.4 ng/mL) were higher than those in radical prostatectomy patients (5.2 +/- 1.3 ng/mL) and healthy subjects (4.5 +/- 1.2 ng/mL) (P <.001). In a preoperative analysis, preoperative plasma TGF-beta(1) level and biopsy Gleason sum both were predictors of organ-confined disease (P =.006 and P =.006, respectively) and PSA progression (P <.001 and P =.021, respectively). In a postoperative multivariate analysis, preoperative plasma TGF-beta(1) level, pathologic Gleason sum, and surgical margin status were predictors of PSA progression (P =.020,P =.020, and P =.022, respectively). In patients who progressed, preoperative plasma TGF-beta(1) levels were higher in those with presumed distant compared with local-only failure (P =.019).

CONCLUSION

Plasma TGF-beta(1) levels are markedly elevated in men with prostate cancer metastatic to regional lymph nodes and bone. In men without clinical or pathologic evidence of metastases, the preoperative plasma TGF-beta(1) level is a strong predictor of biochemical progression after surgery, presumably because of an association with occult metastatic disease present at the time of radical prostatectomy.

Role of transforming growth factor beta in cancer

Transforming growth factor beta (TGF-beta) is an effective and ubiquitous mediator of cell growth. The significance of this cytokine in cancer susceptibility, cancer development and progression has become apparent over the past few years. TGF-beta plays various roles in the process of malignant progression. It is a potent inhibitor of normal stromal, hematopoietic, and epithelial cell growth. However, at some point during cancer development the majority of transformed cells become either partly or completely resistant to TGF-beta growth inhibition. There is growing evidence that in the later stages of cancer development TGF-beta is actively secreted by tumor cells and not merely acts as a bystander but rather contributes to cell growth, invasion, and metastasis and decreases host-tumor immune responses. Subtle alteration of TGF-beta signaling may also contribute to the development of cancer. These various effects are tissue and tumor dependent. Identifying and understanding TGF-beta signaling pathway abnormalities in various malignancies is a promising avenue of study that may yield new modalities to both prevent and treat cancer. The nature, prevalence, and significance of TGF-beta signaling pathway alterations in various forms of human cancer as well as potential preventive and therapeutic interventions are discussed in this review.

Role of transforming growth factor beta in cancer

Transforming growth factor beta (TGF-beta) is an effective and ubiquitous mediator of cell growth. The significance of this cytokine in cancer susceptibility, cancer development and progression has become apparent over the past few years. TGF-beta plays various roles in the process of malignant progression. It is a potent inhibitor of normal stromal, hematopoietic, and epithelial cell growth. However, at some point during cancer development the majority of transformed cells become either partly or completely resistant to TGF-beta growth inhibition. There is growing evidence that in the later stages of cancer development TGF-beta is actively secreted by tumor cells and not merely acts as a bystander but rather contributes to cell growth, invasion, and metastasis and decreases host-tumor immune responses. Subtle alteration of TGF-beta signaling may also contribute to the development of cancer. These various effects are tissue and tumor dependent. Identifying and understanding TGF-beta signaling pathway abnormalities in various malignancies is a promising avenue of study that may yield new modalities to both prevent and treat cancer. The nature, prevalence, and significance of TGF-beta signaling pathway alterations in various forms of human cancer as well as potential preventive and therapeutic interventions are discussed in this review.

Structural changes and alteration in expression of TGF-beta1 and its receptors in prostatic intraepithelial neoplasia (PIN) in the ventral prostate of noble rats

BACKGROUND

Prostatic intraepithelial neoplasia (PIN) is the most likely pre-cancereous lesion and represents the major target for chemoprevention of prostate cancer. The multi-functional role of TGF-beta1, together with its receptors, in normal prostate and development of prostatic neoplasia remains controversial and requires further investigation.

METHODS

Ventral prostates were removed from Noble rats treated with a combination of testosterone (T) and estradiol (E(2)) for various periods of time, and processed for ultrastructural examination and histopathological grading. To evaluate the role of TGF-beta1 and TGFbeta receptor types I and II in normal prostate and high-grade PIN development, expression pattern of TGF-beta1 and TGFbeta-RI and TGFbeta-RII were studied on prostate samples with PIN lesions.

RESULTS

Pathologically, low-grade PIN (LGPIN) and high-grade PIN (HGPIN) were observed in ducts or alveoli after three and five months of T + E(2) treatment, respectively. EM study revealed that HGPIN cells were characterized by a reduction in abundance of secretory apparatus and the nucleus with highly irregular and undulated membrane and often with inclusion bodies although the basal lamina remained largely normal. This was associated with a high level of expression of TGF-beta1 in stromal tissue subjacent to foci of HGPIN. No definite positive reactivity of TGF-beta1 was identified in glandular epithelial cells of HGPIN. These results implicated that the major site for the TGF-beta1 production remained to be restricted to stromal compartment at the stage of HGPIN, and a paracrine regulation of TGF-beta1 might be involved in the development of HGPIN. Positive staining for the TGFbeta-RI was found in the cytoplasm of luminal epithelial cells of normal ventral prostate. The intense positive reactivity for TGFbeta-RI was also identified in prostates with HGPIN lesions. Similar expression pattern of TGFbeta-RII was also observed.

CONCLUSIONS

Based on the EM study, we concluded that HGPIN in ventral prostate was accompanied with alterations in nuclear morphology together with a change in secretory activity. The over expression of TGFbeta-RI and RII in HGPIN cells as well as TGF-beta1 in stromal tissue subjacent to HGPIN implicated a growth-stimulating role instead of inhibiting role of this peptide growth factor during the early stage of prostatic neoplasia.

Analysis of cyclin-dependent kinase inhibitor expression and methylation patterns in human prostate cancers

BACKGROUND

Downregulation of genes which negatively control cell cycle progression represents a possible mechanism for prostate tumorigenesis. We examined the expression levels of the p16, p15, p14, and retinoblastoma-susceptibility (RB) genes in primary prostate cancers and human prostate cancer cell lines, and correlated this with the DNA methylation levels of two loci in p16.

METHODS

The mRNA levels of p16, p15, and p14 were examined by reverse transcriptase-PCR (RT-PCR). DNA methylation of the p16 5' CpG island was determined by bisulfite genomic sequencing, while methylation of exon 2 shared by the p16 and p14 genes was measured by a quantitative bisulfite-based technique, methylation-sensitive single-nucleotide primer extension (Ms-SNuPE). RB protein levels were assessed by immunohistochemical staining of histologic sections of normal and tumor prostate tissues, using a monoclonal antibody (mAB).

RESULTS

Overexpression of p16 mRNA was found in 6/9 (67) of prostate tumors compared to the adjacent normal prostate, whereas elevated p14 and p15 levels were only observed in 2/9 (22) and 1/6 (17) of prostate cases, respectively. There was no statistically significant association of grade (P = 0.18) and stage (P = 1.00) of prostate cancer to the elevated p16 levels in the tumors. The p16 5' CpG island was completely unmethylated in these tissues. In contrast, exon 2 of p16/p14 was methylated in both the tumor and normal adjacent prostates, and was increased in 8/11 (73) of tumors relative to normal tissues. There was no association between p16 overexpression and increased p16/p14 exon 2 methylation in these tumors (P = 1.00). Diminished RB levels in prostate tumors that had upregulated p16 mRNA were found, although absent RB was also detected in tumors without elevated p16 levels. The expression levels of the two genes, RB and p16, were not correlated statistically (P = 0.16).

CONCLUSIONS

Our studies show that although the levels of the cell cycle regulators p16, p15, p14, and Rb are altered in prostate cancers, there is no apparent correlation to grade, stage, or any pattern of regulation between the related genes. Exon 2 of p16/p14 is methylated in a majority of prostate tumors compared to the unmethylated upstream 5' region, and may be a potential tumor marker for human prostate cancer.

Prediction of gene function by genome-scale expression analysis: prostate cancer-associated genes

We wish to identify genes associated with disease. To do so, we look for novel genes whose expression patterns mimic those of known disease-associated genes, using a method we call Guilt-by-Association (GBA), on the basis of a combinatoric measure of association. Using GBA, we have examined the expression of 40,000 human genes in 522 cDNA libraries, and have discovered several hundred previously unidentified genes associated with cancer, inflammation, steroid-synthesis, insulin-synthesis, neurotransmitter processing, matrix remodeling, and other disease processes. The majority of the genes thus discovered show no sequence similarity to known genes, and thus could not have been identified by homology searches. We present here an example of the discovery of eight genes associated with prostate cancer. Of the 40,000 most-abundant human genes, these 8 are the most closely linked to the known diagnostic genes, and thus are prime targets for pharmaceutical research.

TGF-beta and cancer

The relationships between transforming growth factor-beta (TGF-beta) and cancer are varied and complex. The paradigm that is emerging from the experimental evidence accumulated over the past decade or so is that TGF-beta can play two different and opposite roles with respect to the process of malignant progression. During early stages of carcinogenesis, TGF-beta acts predominantly as a potent tumor suppressor and may mediate the actions of chemopreventive agents such as retinoids and nonsteroidal anti-estrogens. However, at some point during the development and progression of malignant neoplasms, bioactive TGF-betas make their appearance in the tumor microenvironment and the tumor cells escape from TGF-beta-dependent growth arrest. In many cases, this resistance to TGF-beta is the consequence of loss or mutational inactivation of the genes that encode signaling intermediates. These include the types I and II TGF-beta receptors, as well as receptor-associated and common-mediator Smads. The stage of tumor development or progression at which TGF-beta-resistant clones come to dominate the tumor cell population in different types of neoplasm remains to be defined. The phenotypic switch from TGF-beta-sensitivity to TGF-beta-resistance that occurs during carcinogenesis has several important implications for cancer prevention and treatment.

Growth factors in expressed prostatic fluid from men with prostate cancer, BPH, and clinically normal prostates

BACKGROUND

Although growth factors such as epidermal growth factor (EGF), transforming growth factor (TGF)-alpha, and TGF-beta are important regulators of prostate cell growth in vitro and in animal models, evidence to support their role in human prostate cancer development remains sparse. We previously showed that men without prostate cancer have concentrations of EGF and TGF-alpha in expressed prostatic fluid (EPF) that are individually distinct and stable over time. This study addressed whether growth factor levels in EPF are associated with the presence or progression of prostate cancer.

METHODS

We measured levels of immunoreactive EGF, TGF-alpha, and TGF-beta1 in stored EPF samples from three age-matched groups: 19 men with untreated, histologically diagnosed prostate cancer (CaP), 38 with benign prostate hyperplasia (BPH), and 19 with normal prostate glands (NPD).

RESULTS

Median TGF-alpha was lower in the BPH group (0.45 ng/ml) than in either CaP (0.63 ng/ml) or NPD (0.58 ng/ml) groups (P = 0.03 and 0.12, respectively). For EGF, the median was lowest in the CaP group and highest in the NPD group (92.5 ng/ml vs. 175.5 ng/ml, P = 0.006). For TGF-beta1, the median level in CaP was 2.7 times higher than the median level among all controls (6.65 ng/ml vs. 2.46 ng/ml, P = 0.002). Growth factor levels were not associated with tumor stage or Gleason score. However, the single case with distant metastases had TGF-beta1 levels 23-fold higher than the CaP median.

CONCLUSIONS

The results suggest that at the time of CaP diagnosis, EGF levels in EPF are significantly lower, and TGF-beta1 levels significantly higher, than normal. Marked overexpression of TGF-beta1 in advanced CaP might be reflected in extremely high EPF levels.

C-CAM1 expression: differential effects on morphology, differentiation state and suppression of human PC-3 prostate carcinoma cells

Studies in rat prostate and liver have suggested that C-CAM1 is involved in the formation and maintenance of histotypic associations in tissues and possibly tumors. Most recently, C-CAM1 has been shown to suppress tumorigenicity of prostate and colon carcinoma cells. However, the mechanisms whereby C-CAM1 suppresses growth and the relationship of this activity to its proposed role in histotypic interactions remain largely unknown. In the present study, we have analysed the growth, phenotypic, morphological and ultrastructural characteristics of four human PC-3 prostate carcinoma cell lines transduced with C-CAM1 retrovirus. We report that three of four lines regained their tumorigenic phenotype in vivo while maintaining high levels of C-CAM1 expression and a growth retarded phenotype in vitro. These findings suggested that high levels of C-CAM1 expression were negatively influencing recovery during reconstitution after freezing or during the latency period after subcutaneous injection and that loss of suppression resulted from changes in expression of other molecules required for full disclosure of C-CAM1 mediated growth inhibition. Results from Northern blot and immunofluorescence analyses of tumor nodules demonstrated that C-CAM1 decreased rather than enhanced phenotypic differentiation and induced ultrastructural and morphological changes that occurred independently of tumor suppression.

Elevated serum levels of transforming growth factor-beta1 in patients with colorectal carcinoma: its association with tumor progression and its significant decrease after curative surgical resection

BACKGROUND

Transforming growth factor-beta1 (TGF-beta1) acts as a potent inhibitor of cell growth and tumor progression but loss of this negative regulation can contribute to tumor development. Some studies have reported an association between disease progression and TGF-beta1 expression in patients with colorectal carcinoma, but their results were not always consistent.

METHODS

Serum levels of TGF-beta1 were measured using an enzyme-linked immunoadsorbent assay in 121 consecutive patients with colorectal carcinoma and compared with TGF-beta1 serum levels in 31 healthy volunteers. Serum levels of TGF-beta1 also were measured in 50 patients who underwent curative surgical resection (part of the 121 preoperative patients) to compare their levels with preoperative serum levels of TGF-beta1.

RESULTS

Serum levels of TGF-beta1 in patients with colorectal carcinoma (45+/-15 ng/mL) (mean+/-the standard deviation) were significantly higher than those in the healthy control group (32+/-4 ng/mL) (P = 0.001). Serum levels of TGF-beta1 increased with increasing tumor stage (P < 0.01). Serum levels of TGF-beta1 were correlated significantly with depth of tumor invasion, lymph node metastasis, distant metastasis, and serum levels of carcinoembryonic antigen (CEA). Serum levels of TGF-beta1 tended to increase with increasing CEA (correlation coefficient = 0.21; P < 0.05). The mean serum level of TGF-beta1 in patients with colorectal carcinoma before surgery (45+/-14 ng/mL) (n = 50) significantly decreased to 34+/-7 ng/mL, which was within the normal range (32+/-4 ng/mL), after curative surgical resection of the tumor (P = 0.0000). Serum levels of TGF-beta1 after tumor resection decreased more significantly in patients with higher preoperative levels of TGF-beta1 (from 53+/-12 ng/mL to 36+/-6 ng/mL) (n = 30).

CONCLUSIONS

The results of the current study suggest that serum levels of TGF-beta1 in colorectal carcinoma patients may be associated with disease progression and may be used as a biomarker in the management of colorectal carcinoma patients. The authors believe further studies with a large number of patients for a longer follow-up period are necessary to conclude whether serum levels of TGF-beta1 carry significant clinical relevance.

Elevated levels of circulating interleukin-6 and transforming growth factor-beta1 in patients with metastatic prostatic carcinoma

PURPOSE

Specific cytokines have been found to be secreted by and influence the growth of prostate cancers in cell culture. Interleukin-6 (IL-6), tumor necrosis factor alpha (TNFalpha), granulocyte macrophage-colony stimulating factor (GM-CSF) and transforming growth factor-beta1 (TGF-beta1) have all been closely associated with prostate cancer. We analyzed the levels of these cytokines in the systemic circulation of patients with varying stages of prostate cancer compared to controls.

MATERIALS AND METHODS

Serum IL-6, TNFalpha and GM-CSF were measured using commercially available enzyme linked immunosorbent assays in 5 groups of patients, including controls-19 men presenting to prostate cancer screening with normal digital rectal examination and serum prostate specific antigen (PSA) no greater than 2.0 ng./ml., stage pT2-19 with cancer confined to the prostate in the radical prostatectomy specimen, stage pT3-10 with extraprostatic extension and/or seminal vesicle involvement, stage N1-12 with lymph node metastases at pelvic lymph node dissection, and stage M1-9 with bone metastases. Platelet poor plasma TGF-beta1 was measured using a commercially available enzyme linked immunosorbent assay in controls and patients with stage M1 disease only because it was not available for patients with stages pT2, pT3 and N1 disease. No patient had a history of any other malignancy. All blood specimens were collected before surgery and/or androgen ablation. Statistical analysis was done with the Kruskal-Wallis analysis of variance.

RESULTS

Serum IL-6 and platelet poor plasma TGF-beta1 were significantly elevated in patients with clinically evident metastases (p = 0.0008 and 0.0412, respectively) while serum GM-CSF and TNFalpha were not. IL-6 and TGF-beta1 correlated with increasing serum PSA (p = 0.0335 and 0.0386, respectively). GM-CSF did not correlate with PSA or age. In multivariate analysis TNFalpha correlated with age but not PSA.

CONCLUSIONS

IL-6 and TGF-beta1 correlate with tumor burden as assessed by serum PSA or clinically evident metastases. Further research is needed to determine the response to androgen ablation as well as the source(s) and actions of these cytokines.

Elevated serum levels of transforming growth factor-beta1 in patients with colorectal carcinoma: its association with tumor progression and its significant decrease after curative surgical resection

BACKGROUND

Transforming growth factor-beta1 (TGF-beta1) acts as a potent inhibitor of cell growth and tumor progression but loss of this negative regulation can contribute to tumor development. Some studies have reported an association between disease progression and TGF-beta1 expression in patients with colorectal carcinoma, but their results were not always consistent.

METHODS

Serum levels of TGF-beta1 were measured using an enzyme-linked immunoadsorbent assay in 121 consecutive patients with colorectal carcinoma and compared with TGF-beta1 serum levels in 31 healthy volunteers. Serum levels of TGF-beta1 also were measured in 50 patients who underwent curative surgical resection (part of the 121 preoperative patients) to compare their levels with preoperative serum levels of TGF-beta1.

RESULTS

Serum levels of TGF-beta1 in patients with colorectal carcinoma (45+/-15 ng/mL) (mean+/-the standard deviation) were significantly higher than those in the healthy control group (32+/-4 ng/mL) (P = 0.001). Serum levels of TGF-beta1 increased with increasing tumor stage (P < 0.01). Serum levels of TGF-beta1 were correlated significantly with depth of tumor invasion, lymph node metastasis, distant metastasis, and serum levels of carcinoembryonic antigen (CEA). Serum levels of TGF-beta1 tended to increase with increasing CEA (correlation coefficient = 0.21; P < 0.05). The mean serum level of TGF-beta1 in patients with colorectal carcinoma before surgery (45+/-14 ng/mL) (n = 50) significantly decreased to 34+/-7 ng/mL, which was within the normal range (32+/-4 ng/mL), after curative surgical resection of the tumor (P = 0.0000). Serum levels of TGF-beta1 after tumor resection decreased more significantly in patients with higher preoperative levels of TGF-beta1 (from 53+/-12 ng/mL to 36+/-6 ng/mL) (n = 30).

CONCLUSIONS

The results of the current study suggest that serum levels of TGF-beta1 in colorectal carcinoma patients may be associated with disease progression and may be used as a biomarker in the management of colorectal carcinoma patients. The authors believe further studies with a large number of patients for a longer follow-up period are necessary to conclude whether serum levels of TGF-beta1 carry significant clinical relevance.

Interleukin-8 serum levels in patients with benign prostatic hyperplasia and prostate cancer

OBJECTIVES

Using arbitrarily primed polymerase chain reaction (AP-PCR) ribonucleic acid (RNA) fingerprinting, we discovered a messenger RNA (mRNA) that encoded the cytokine interleukin-8 (IL-8) that was up-regulated in the peripheral blood leukocytes (PBLs) of patients with metastatic prostate cancer (CaP) compared with similar cells from healthy individuals. We compared the total prostate-specific antigen (PSA) levels, the free/total (f/t) PSA ratios, and the immunoreactive IL-8 serum concentrations in patients with either biopsy-confirmed benign prostatic hyperplasia (BPH) or CaP.

METHODS

The sera from 35 apparently healthy normal volunteers and 146 patients with biopsy-confirmed BPH and CaP obtained from two academic centers were retrospectively examined to determine the serum levels of IL-8, total PSA (tPSA), and the f/t PSA ratio. Logistic regression and trend analysis statistical methods were used to assess the results.

RESULTS

Normals (n = 35), BPH patients (n = 53), patients with clinical Stages A to C CaP (n = 81), and patients with metastatic CaP (n = 1 2) had mean levels of IL-8 of 6.8, 6.5, 15.6, and 27.8 pg/mL, respectively. The IL-8 serum concentrations correlated with increasing CaP stage and also differentiated BPH from clinical Stages A, B, C, or D CaP better than tPSA and performed similarly to the f/t PSA ratio. The combination of the IL-8 levels and f/t PSA ratios using multivariate logistic regression analysis distinguished BPH from Stages A, B, C, or D CaP or only Stages A and B with a receiver operating characteristic area under the curve of 89.8% and 87.5%, respectively (P <0.0001).

CONCLUSIONS

The IL-8 serum concentration in our clinically well-defined patient sample was independent of the f/t PSA ratio as a predictor of CaP. When test samples are controlled for extraneous clinical origin of inflammation or infection, the combination of the IL-8 and f/t PSA assay results may offer an improved approach for distinguishing BPH from CaP.