SERUM KERATINOCYTE GROWTH FACTOR MEASUREMENT IN PATIENTS WITH PROSTATE CANCER

Intrinsic and extrinsic factors causing hyperplasia of the prostate

Prostatic hyperplasia is very common in elderly men and is a typical disease that reduces quality of life. Histologically, hyperplasia of the prostate gland causes obstruction at the bladder outlet, resulting in symptoms such as a weak urine stream. Various factors have been considered to cause histological enlargement of the prostate, but the underlying cause is still unknown. The factors that cause prostate hyperplasia can be broadly classified into intrinsic and extrinsic ones. Extrinsic factors include things that we directly come into contact with such as bacteria and food. On the other hand, intrinsic factors are those that cause changes in functions originally provided in the body due to some cause, including extrinsic factors, such as chronic inflammation and an imbalance of sex hormones. A large number of reports have been made to date regarding the etiology of prostatic hyperplasia, although they have not yet clarified the fundamental cause(s). The various factors currently known should be outlined for future research. Should it be possible to prevent this highly prevalent prostatic hyperplasia which is mainly cause of dcreasing quality of life, there is no doubt that it would be a huge contribution to humanity.

The FGF/FGFR system in the physiopathology of the prostate gland

Fibroblast growth factors (FGFs) are a family of proteins possessing paracrine, autocrine, or endocrine functions in a variety of biological processes, including embryonic development, angiogenesis, tissue homeostasis, wound repair, and cancer. Canonical FGFs bind and activate tyrosine kinase FGF receptors (FGFRs), triggering intracellular signaling cascades that mediate their biological activity. Experimental evidence indicates that FGFs play a complex role in the physiopathology of the prostate gland that ranges from essential functions during embryonic development to modulation of neoplastic transformation. The use of ligand- and receptor-deleted mouse models has highlighted the requirement for FGF signaling in the normal development of the prostate gland. In adult prostate, the maintenance of a functional FGF/FGFR signaling axis is critical for organ homeostasis and function, as its disruption leads to prostate hyperplasia and may contribute to cancer progression and metastatic dissemination. Dissection of the molecular landscape modulated by the FGF family will facilitate ongoing translational efforts directed toward prostate cancer therapy.

Vibrational spectroscopy of liquid biopsies for prostate cancer diagnosis

Background:

Screening for prostate cancer with prostate specific antigen and digital rectal examination allows early diagnosis of prostate malignancy but has been associated with poor sensitivity and specificity. There is also a considerable risk of over-diagnosis and over-treatment, which highlights the need for better tools for diagnosis of prostate cancer. This study investigates the potential of high throughput Raman and Fourier Transform Infrared (FTIR) spectroscopy of liquid biopsies for rapid and accurate diagnosis of prostate cancer.

Methods:

Blood samples (plasma and lymphocytes) were obtained from healthy control subjects and prostate cancer patients. FTIR and Raman spectra were recorded from plasma samples, while Raman spectra were recorded from the lymphocytes. The acquired spectral data was analysed with various multivariate statistical methods, principal component analysis (PCA), partial least squares discriminant analysis (PLS-DA) and classical least squares (CLS) fitting analysis.

Results:

Discrimination was observed between the infrared and Raman spectra of plasma and lymphocytes from healthy donors and prostate cancer patients using PCA. In addition, plasma and lymphocytes displayed differentiating signatures in patients exhibiting different Gleason scores. A PLS-DA model was able to discriminate these groups with sensitivity and specificity rates ranging from 90% to 99%. CLS fitting analysis identified key analytes that are involved in the development and progression of prostate cancer.

Conclusions:

This technology may have potential as an alternative first stage diagnostic triage for prostate cancer. This technology can be easily adaptable to many other bodily fluids and could be useful for translation of liquid biopsy-based diagnostics into the clinic.

Excess FGF-7 in corneal epithelium causes corneal intraepithelial neoplasia in young mice and epithelium hyperplasia in adult mice

We hypothesized that human ocular surface squamous neoplasia (OSSN) may result from the continuous growth stimulation of corneal epithelial progenitor cells. In the present study, we analyzed the effects of excess fibroblast growth factor-7 (FGF-7) on both the proliferation and differentiation of corneal epithelium in a novel Krt12-rtTA/tet-O-FGF-7 double transgenic mouse model in which cornea-specific FGF-7 overexpression is achieved by doxycycline (Dox) treatment. When such adult mice were exposed to Dox, they exhibited epithelial hyperplasia with increases in phospho-extracellular signal-regulated kinase 1/2-, nuclear beta-catenin-, and 5-bromo-2'-deoxyuridine-labeled cells and altered keratin (K) 14 (K14) expression pattern, a normal K12 expression pattern, and the normal absence of K10. Hyperplasia of the adult cornea was fully reversible 2 weeks after the removal of Dox from chow. In contrast, double transgenic embryos that were exposed to Dox from embryonic day 0.5 to postnatal day 21 developed papillomatous tumors in the cornea, resembling human OSSN, and ectopic gland-like structures in the limbus, accompanied by the down-regulation of K12 and the up-regulation of K14, Pax6, and p63. These epithelial anomalies observed in young experimental mice were not fully resolved after the termination of Dox induction. Taken together, Krt12-rtTA/tet-O-FGF-7 mice may be a suitable animal model for the study of the molecular and cellular mechanisms of human OSSN.

Hepatocyte growth factor and interleukin-6 in combination with prostate volume are possible prostate cancer tumor markers in patients with gray-zone PSA levels

The aim was to assess whether hepatocyte growth factor (HGF) and interleukin (IL)-6 in combination with prostate volume are able to accurately detect prostate cancer in patients with gray-zone prostate-specific antigen (PSA) levels. A total of 159 patients with PSA levels of <10 ng ml(-1) were enrolled. Forty-two (35.3%) were diagnosed with prostate cancer, whereas 117 (64.7%) had no cancer and were used as benign group. HGF and IL-6 density (HGFD and IL-6D, respectively) values were calculated by dividing serum HGF and IL-6 levels with prostate volume. Median IL-6 (2.3 pg ml(-1)) levels for the prostate cancer group were significantly higher than those for the benign group before adjustment for age (1.7 pg ml(-1)) (P=0.0098). After age adjustments, median IL-6 (2.17 pg ml(-1)), HGFD (0.00972 ng ml(-1) cm(-3)), and IL-6D (0.0848 pg ml(-1) cm(-3)) values for the prostate cancer group were significantly higher than those for the benign group (IL-6, 1.78 pg ml(-1); HGFD, 0.00732 ng/ml/cc; and IL-6D, 0.049 pg/ml/cc; P=0.0416, 0.007 and 0.0005, respectively). In receiver operating characteristic analyses, the areas under the curves for HGFD (0.64) and IL-6D (0.68) were significantly greater than those for HGF (0.52) and IL-6 (0.61) (P=0.0006 and 0.019, respectively). With an HGFD cutoff value of 0.00392 ng ml(-1) cm(-3) (sensitivity=100%, specificity=11%), 11.1% of the benign group were able to avoid unnecessary biopsies without missing prostate cancer. HGF and IL-6 levels in combination with prostate volume were shown to be useful parameters for prostate cancer screening in patients with gray-zone PSA levels.

Fibroblast growth factors and their receptors in urological cancers: basic research and clinical implications

Because therapeutical options for advanced urological cancers are limited, the understanding of key elements responsible for invasion and metastasis is very important. It has been hypothesized that progression to malignant growth is associated with a dysregulation of growth factors and/or their receptors. In the last few years, signaling pathways of the fibroblast growth factor (FGF) family have been subject to intense investigation. Fibroblast growth factors constitute one of the largest families of growth and differentiation factors for cells of mesodermal and neuroectodermal origin. The family comprises two prototypic members, acidic FGF (aFGF) and the basic FGF (bFGF), as well as 21 additionally related polypeptide growth factors that have been identified to date. FGFs are involved in many biological processes during embryonic development, wound healing, hematopoesis, and angiogenesis. In prostate, bladder, and renal cancers, FGFs regulate the induction of metalloproteinases (MMP) that degrade extracellular matrix proteins, thus facilitating tumor metastasis. Probably due to their potent angiogenic properties, aFGF and bFGF have received the most attention. However, there is increasing evidence that other FGFs also play crucial roles in tumors of the prostate, bladder, kidney, and testis. This review will discuss the different elements involved in FGF signaling and summarize the present knowledge of their biological and clinical relevance in urological cancers.

Heparin-binding epidermal growth factor-like growth factor stimulates androgen-independent prostate tumor growth and antagonizes androgen receptor function

Peptide growth factors have been implicated in progression of prostate cancer (PCa) to the androgen-independent state; however, much of the evidence linking diffusible mitogens and survival factors to this process remains circumstantial. Heparin-binding epidermal growth factor-like growth factor (HB-EGF), a prostate stroma-derived factor, promotes survival, proliferation, and neuroendocrine differentiation of androgen-dependent LNCaP PCa cells in vitro. To test whether sustained exposure to HB-EGF can confer an androgen-independent phenotype, we generated stable populations of LNCaP cells that express constitutively a secreted form of HB-EGF (LNCaP/sHB). LNCaP/sHB cells proliferated more rapidly under androgen-depleted conditions in vitro and formed larger tumors with higher frequency in intact and castrated severe combined immunodeficient mice, in comparison to control cells. LNCaP/sHB tumors also expressed higher levels of the neuroendocrine marker, neuron-specific enolase, compared with control tumors. In castrates, increased neuron-specific enolase expression in LNCaP/sHB tumors was associated with reduced androgen receptor (AR) levels. In vitro, AR protein levels were reduced in LNCaP/sHB cells, and in transient transfection assays using an androgen-responsive promoter (mouse mammary tumor virus-long terminal repeat), LNCaP/sHB cells showed reduced sensitivity to dihydrotestosterone compared with controls. This is the first demonstration that continuous exposure of AR-positive PCa cells to a single growth factor can promote an androgen-independent phenotype in vivo. These findings also emphasize the potential role of pathways other than the AR axis in acquisition of androgen independence.

Ribozyme-targeting of a secreted FGF-binding protein (FGF-BP) inhibits proliferation of prostate cancer cells in vitro and in vivo

Prostate cancer is one of the most common malignant tumors with increasing incidence rates in the aging male. Since locally advanced or metastatic prostate tumors are essentially incurable, identification of new target molecules and treatment strategies is of critical importance. Fibroblast growth factor-2 (FGF-2) acts as potent mitogen which is upregulated in prostate cancers modulating cancer cell proliferation and development of an invasive phenotype. Normally it is tightly bound to the extracellular matrix that quenches its biological activity. The FGF-binding proteins (FGF-BP, HBp17) is a secreted protein which is able to mobilize and activate FGF-2 from the extracellular matrix. Here we show that FGF-BP is highly expressed in prostate tumor cells. To study the functional role of FGF-BP, we use a ribozyme-targeting approach to selectively deplete FGF-BP in prostate cancer cells achieving a more than 50% reduction of FGF-BP mRNA and protein levels in two mass-transfected cell lines. FGF-BP depletion reduces proliferation of the cells in vitro without changes in cell cycle distribution or apoptosis. Using cDNA microarrays, Northern blotting and RT-PCR, we show a complex pattern of changes in the gene expression profiles upon FGF-BP depletion. Most strikingly, ribozyme-mediated reduction of FGF-BP levels completely abolishes the ability of the highly metastatic PC-3 prostate carcinoma cells to grow tumors in an athymic nude mouse in vivo model which is far beyond the effects of FGF-BP ribozyme targeting observed previously in cells from other tumors in the same model. Taken together, our study identifies FGF-BP as a potential rate-limiting factor for prostate cancer growth and, due to its restricted expression pattern in adults, a potentially attractive target for prostate cancer therapy.

Induction of FGF receptor 2-IIIb expression and response to its ligands in epithelial ovarian cancer

Epithelial ovarian cancers (EOCs) arise in the Ovarian Surface Epithelium (OSE). This tissue is a simple, poorly committed mesothelium which exhibits characteristics of epithelial and mesenchymal cells when grown in culture. In contrast, EOCs frequently exhibit properties of complex epithelial tissues of the female reproductive tract, such as oviductal, endometrial and cervical epithelia, and show induction of expression of epithelial markers such as E-cadherin. Fibroblast Growth Factor Receptor 2 isoform IIIb (FGF receptor 2-IIIb) is a spliced variant of FGF receptor 2 that binds the ligands FGF-1 and FGF-7 with high affinity, and is expressed exclusively by epithelial cells. We have studied the expression of FGF receptor 2-IIIb and its ligands in primary cultures of normal human OSE, EOC cell lines and snap frozen tissue from EOCs. Expression of FGF receptor 2-IIIb mRNA is undetectable in normal OSE, but is expressed in 16/20 (80%) of EOCs. FGFs 1 and 7 mRNAs are expressed in normal OSE, whilst only 4/20 (20%) and 12/20 (60%) of EOCs demonstrated expression for these ligands respectively. However, FGF-7 protein was detected in 70% (mean level=0.7 ng/ml) of ascitic fluids obtained from patients with EOC. FGFs 1 and 7 stimulate DNA synthesis in EOC cell lines that express FGF receptor 2-IIIb. Moreover, DNA synthesis in these cell lines can be partially blocked by blocking antisera to FGFs 1 and 7. It is suggested that induction of expression of FGF receptor 2-IIIb may play a role in the development of EOCs by rendering the OSE susceptible to paracrine and/or autocrine stimulation by its requisite FGF ligands.