FGF signaling in prostate tumorigenesis--new insights into epithelial-stromal interactions

CDCA7 promotes TGF-β-induced epithelial-mesenchymal transition via transcriptionally regulating Smad4/Smad7 in ESCC

Cell division cycle associated 7 (CDCA7) is a copy number amplification gene that contributes to the metastasis and invasion of tumors, including esophageal squamous cell carcinoma (ESCC). This present study aimed at clarifying whether high expression of CDCA7 promotes the metastasis and invasion of ESCC cell lines and exploring the underlying mechanisms implicated in epithelial-mesenchymal transition (EMT) of ESCC. The role of CDCA7 in the regulation of ESCC metastasis and invasion was evaluated using ESCC cell lines. Expression of EMT-related markers including E-cadherin, N-cadherin, Vimentin, Snail, and Slug, transforming growth factor β (TGF-β) signaling pathway including Smad2/3, p-Smad2/3, Smad4, and Smad7 were detected in CDCA7 knockdown and overexpressed cell lines. Dual-luciferase reporter assay and rescue assay were used to explore the underlying mechanisms that CDCA7 contributed to the metastasis and invasion of ESCC. High CDCA7 expression significantly promoted the metastasis and invasion of ESCC cell lines both in vivo and in vitro. Additionally, the expression of CDCA7 positively correlated with the expression of N-cadherin, Vimentin, Snail, Slug, TGF-β signaling pathway and negatively correlated with the expression of E-cadherin. Furthermore, CDCA7 transcriptionally regulated the expression of Smad4 and Smad7. Knockdown of CDCA7 inhibited the TGF-β signaling pathway and therefore inhibited EMT. Our data indicated that CDCA7 was heavily involved in EMT by regulating the expression of Smad4 and Smad7 in TGF-β signaling pathway. CDCA7 might be a new therapeutic target in the suppression of metastasis and invasion of ESCC.

Signaling pathways and targeted therapies in lung squamous cell carcinoma: mechanisms and clinical trials

Lung cancer is the leading cause of cancer-related death across the world. Unlike lung adenocarcinoma, patients with lung squamous cell carcinoma (LSCC) have not benefitted from targeted therapies. Although immunotherapy has significantly improved cancer patients' outcomes, the relatively low response rate and severe adverse events hinder the clinical application of this promising treatment in LSCC. Therefore, it is of vital importance to have a better understanding of the mechanisms underlying the pathogenesis of LSCC as well as the inner connection among different signaling pathways, which will surely provide opportunities for more effective therapeutic interventions for LSCC. In this review, new insights were given about classical signaling pathways which have been proved in other cancer types but not in LSCC, including PI3K signaling pathway, VEGF/VEGFR signaling, and CDK4/6 pathway. Other signaling pathways which may have therapeutic potentials in LSCC were also discussed, including the FGFR1 pathway, EGFR pathway, and KEAP1/NRF2 pathway. Next, chromosome 3q, which harbors two key squamous differentiation markers SOX2 and TP63 is discussed as well as its related potential therapeutic targets. We also provided some progress of LSCC in epigenetic therapies and immune checkpoints blockade (ICB) therapies. Subsequently, we outlined some combination strategies of ICB therapies and other targeted therapies. Finally, prospects and challenges were given related to the exploration and application of novel therapeutic strategies for LSCC.

Resistance to prostate cancer treatments

A review of the current treatment options for prostate cancer and the formation of resistance to these regimens has been compiled including primary, acquired, and cross-resistance. The diversification of the pathways involved and the escape routes the tumor is utilizing have been addressed. Whereas early stages of tumor can be cured, there is no treatment available after a point of no return has been reached, leaving palliative treatment as the only option. The major reasons for this outcome are the heterogeneity of tumors, both inter- and intra-individually and the nearly endless number of escape routes, which the tumor can select to overcome the effects of treatment. This means that more focus should be applied to the individualization of both diagnosis and therapy of prostate cancer. In addition to current treatment options, novel drugs and ongoing clinical trials have been addressed in this review.

A Review of the Pathophysiological Mechanisms Underlying Castration-resistant Prostate Cancer

Androgen deprivation therapy or ADT is one of the cornerstones of management of locally advanced or metastatic prostate cancer, alongside radiation therapy. However, despite early response, most advanced prostate cancers progress into an androgen unresponsive or castrate resistant state, which hitherto remains an incurable entity and the second leading cause of cancer-related mortality in men in the US. Recent advances have uncovered multiple complex and intermingled mechanisms underlying this transformation. While most of these mechanisms revolve around androgen receptor (AR) signaling, novel pathways which act independently of the androgen axis are also being discovered. The aim of this article is to review the pathophysiological mechanisms that help bypass the apoptotic effects of ADT to create castrate resistance. The article discusses castrate resistance mechanisms under two categories: 1. Direct AR dependent pathways such as amplification or gain of function mutations in AR, development of functional splice variants, posttranslational regulation, and pro-oncogenic modulation in the expression of coactivators vs corepressors of AR. 2. Ancillary pathways involving RAS/MAP kinase, TGF-beta/SMAD pathway, FGF signaling, JAK/STAT pathway, Wnt-Beta catenin and hedgehog signaling as well as the role of cell adhesion molecules and G-protein coupled receptors. miRNAs are also briefly discussed. Understanding the mechanisms involved in the development and progression of castration-resistant prostate cancer is paramount to the development of targeted agents to overcome these mechanisms. A number of targeted agents are currently in development. As we strive for more personalized treatment across oncology care, treatment regimens will need to be tailored based on the type of CRPC and the underlying mechanism of castration resistance.

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.

Emerging Roles of Fibroblast Growth Factor 10 in Cancer

Whilst cross-talk between stroma and epithelium is critical for tissue development and homeostasis, aberrant paracrine stimulation can result in neoplastic transformation. Chronic stimulation of epithelial cells with paracrine Fibroblast Growth Factor 10 (FGF10) has been implicated in multiple cancers, including breast, prostate and pancreatic ductal adenocarcinoma. Here, we examine the mechanisms underlying FGF10-induced tumourigenesis and explore novel approaches to target FGF10 signaling in cancer.

Aberrant FGFR Tyrosine Kinase Signaling Enhances the Warburg Effect by Reprogramming LDH Isoform Expression and Activity in Prostate Cancer

The acquisition of ectopic fibroblast growthfactor receptor 1 (FGFR1) expression is well documented in prostate cancer progression. How it contributes to prostate cancer progression is not fully understood, although it is known to confer a growth advantage and promote cell survival. Here, we report that FGFR1 tyrosine kinase reprograms the energy metabolism of prostate cancer cells by regulating the expression of lactate dehydrogenase (LDH) isozymes. FGFR1 increased LDHA stability through tyrosine phosphorylation and reduced LDHB expression by promoting its promoter methylation, thereby shifting cell metabolism from oxidative phosphorylation to aerobic glycolysis. LDHA depletion compromised, whereas LDHB depletion enhanced the tumorigenicity of prostate cancer cells. Furthermore, FGFR1 overexpression and aberrant LDH isozyme expression were associated with short overall survival and biochemical recurrence times in patients with prostate cancer. Our results indicate that ectopic FGFR1 expression reprograms the energy metabolism of prostate cancer cells, representing a hallmark change in prostate cancer progression.Significance: FGF signaling drives the Warburg effect through differential regulation of LDHA and LDHB, thereby promoting the progression of prostate cancer.Graphical Abstract: http://cancerres.aacrjournals.org/content/canres/78/16/4459/F1.large.jpg Cancer Res; 78(16); 4459-70. ©2018 AACR.

Genome-wide association study of prostate-specific antigen levels identifies novel loci independent of prostate cancer

Prostate-specific antigen (PSA) levels have been used for detection and surveillance of prostate cancer (PCa). However, factors other than PCa—such as genetics—can impact PSA. Here we present findings from a genome-wide association study (GWAS) of PSA in 28,503 Kaiser Permanente whites and 17,428 men from replication cohorts. We detect 40 genome-wide significant (P<5 × 10⁻⁸) single-nucleotide polymorphisms (SNPs): 19 novel, 15 previously identified for PSA (14 of which were also PCa-associated), and 6 previously identified for PCa only. Further analysis incorporating PCa cases suggests that at least half of the 40 SNPs are PSA-associated independent of PCa. The 40 SNPs explain 9.5% of PSA variation in non-Hispanic whites, and the remaining GWAS SNPs explain an additional 31.7%; this percentage is higher in younger men, supporting the genetic basis of PSA levels. These findings provide important information about genetic markers for PSA that may improve PCa screening, thereby reducing over-diagnosis and over-treatment.

Prostate-specific antigen is used as a biomarker of prostate cancer, but levels can be affected by other factors not related to cancer. Here, the authors find genes associated with prostate specific antigen levels in healthy men, which could be used to reduce over-diagnosis and over-treatment.

The oncoprotein HBXIP up-regulates FGF4 through activating transcriptional factor Sp1 to promote the migration of breast cancer cells

We have reported that the oncoprotein hepatitis B X-interacting protein (HBXIP) is able to promote migration of breast cancer cells. Fibroblast growth factor 4 (FGF4) is a multipotent growth factor and is highly expressed in various human cancers. However, the regulatory mechanism of FGF4 in breast cancer remains poorly understood. In the present study, we report that HBXIP is able to up-regulate FGF4 to enhance the migration of breast cancer cells. Immunohistochemistry staining showed that HBXIP and FGF4 were highly expressed in clinical metastatic lymph nodes of breast tumor. The expression levels of HBXIP were positively related to those of FGF4 in clinical breast cancer tissues. Then, we validated that HBXIP up-regulated the expression of FGF4 at the levels of promoter, mRNA and protein by luciferase reporter gene assays, reverse transcription-polymerase chain reaction and Western blot analysis. Moreover, we found that HBXIP was able to activate FGF4 promoter through transcriptional factor Sp1 by luciferase reporter gene assays. Chromatin immunoprecipitation assays confirmed that HBXIP coactivated Sp1 to stimulate FGF4 promoter. In function, we showed that HBXIP promoted breast cancer cell migration through FGF4 by wound healing and transwell cell migration assays. Thus, we conclude that the oncoprotein HBXIP up-regulates FGF4 through activating transcriptional factor Sp1 to promote the migration of breast cancer cells. Therapeutically, HBXIP may serve as a novel target in breast cancer.

FGF1-FGFR1 axis promotes tongue squamous cell carcinoma (TSCC) metastasis through epithelial-mesenchymal transition (EMT)

Increasing evidences suggest a close association between tumor metastasis and the inflammatory factors secreted by tumor microenvironment. It has been reported that epithelial mesenchymal-transition (EMT) plays a significant role during multiple types of tumor metastasis and progression induced by inflammatory factor from tumor microenvironment. Previous researches implied that fibroblast growth factor 1 (FGF1) can promote tumor progression and cause poor prognosis in several types of malignant tumors via interacting with its receptor fibroblast growth factor receptor 1 (FGFR1). However, the effects of FGF1-FGFR1 on tongue squamous cell carcinoma (TSCC) are not yet completely understood. In the present study, we evaluated the effects and function of FGF1-FGFR1 axis on TSCC metastasis. In addition, we investigated whether the EMT pathway is involved in these effects, thus modulating the TSCC progression. The expression of FGFR1 was measured both in tongue cancer cell lines and tissues by qRT-PCR and western blot. We found that FGFR1 was up-regulated in TSCC tissues compared to non-neoplastic tongue tissues. Additionally, overexpression of FGFR1 is positively associated with poor differentiation and metastasis potential. Furthermore, the function of FGF1-FGFR1 was examined in TSCC cell line. The results implied that FGF1 can obviously promote Cal27 cells migration and invasion abilities through FGFR1, while the motile and invasive capabilities can be severely attenuated when knockdown the expression of FGFR1 by specific siRNAs. Further investigation results show that FGF1-FGFR1 axis promotes TSCC metastasis by modulating EMT pathway. However, this effect can be inhibited by blocking the FGF1-FGFR1 axis using FGFR1 specific siRNAs. In conclusion, our findings of the present study provide the evidences that FGF1-FGFR1 axis promotes the TSCC metastasis through the EMT pathway.

Overexpression of FGF9 in prostate epithelial cells augments reactive stroma formation and promotes prostate cancer progression

Bone metastasis is the major cause of morbidity and mortality of prostate cancer (PCa). Fibroblast growth factor 9 (FGF9) has been reported to promote PCa bone metastasis. However, the mechanism by which overexpression of FGF9 promotes PCa progression and metastasis is still unknown. Herein, we report that transgenic mice forced to express FGF9 in prostate epithelial cells (F9TG) developed high grade prostatic intraepithelial neoplasia (PIN) in an expression level- and time-dependent manner. Moreover, FGF9/TRAMP bigenic mice (F9TRAMP) grew advanced PCa earlier and had higher frequencies of metastasis than TRAMP littermates. We observed tumor microenvironmental changes including hypercellularity and hyperproliferation in the stromal compartment of F9TG and F9TRAMP mice. Expression of TGFβ1, a key signaling molecule overexpressed in reactive stroma, was increased in F9TG and F9TRAMP prostates. Both in vivo and in vitro data indicated that FGF9 promoted TGFβ1 expression via increasing cJun-mediated signaling. Moreover, in silico analyses showed that the expression level of FGF9 was positively associated with expression of TGFβ1 and its downstream signaling molecules in human prostate cancers. Collectively, our data demonstrated that overexpressing FGF9 in PCa cells augmented the formation of reactive stroma and promoted PCa initiation and progression.

The host microenvironment influences prostate cancer invasion, systemic spread, bone colonization, and osteoblastic metastasis

Prostate cancer (PCa) is the second leading cause of cancer death in men worldwide. Most PCa deaths are due to osteoblastic bone metastases. What triggers PCa metastasis to the bone and what causes osteoblastic lesions remain unanswered. A major contributor to PCa metastasis is the host microenvironment. Here, we address how the primary tumor microenvironment influences PCa metastasis via integrins, extracellular proteases, and transient epithelia-mesenchymal transition (EMT) to promote PCa progression, invasion, and metastasis. We discuss how the bone-microenvironment influences metastasis; where chemotactic cytokines favor bone homing, adhesion molecules promote colonization, and bone-derived signals induce osteoblastic lesions. Animal models that fully recapitulate human PCa progression from primary tumor to bone metastasis are needed to understand the PCa pathophysiology that leads to bone metastasis. Better delineation of the specific processes involved in PCa bone metastasize is needed to prevent or treat metastatic PCa. Therapeutic regimens that focus on the tumor microenvironment could add to the PCa pharmacopeia.

Fibroblasts induce expression of FGF4 in ovarian cancer stem-like cells/cancer-initiating cells and upregulate their tumor initiation capacity

Cancer stem-like cells (CSCs)/cancer-initiating cells (CICs) are defined as a small population of cells within cancer that contribute to cancer initiation and progression. Cancer-associated fibroblasts (CAFs) are stromal fibroblasts surrounding tumor cells, and they have important roles in tumor growth and tumor progression. It has been suggested that stromal fibroblasts and CSCs/CICs might mutually cooperate to enhance their growth and tumorigenic capacity. In this study, we investigated the effects of fibroblasts on tumor-initiating capacity and stem-like properties of ovarian CSCs/CICs. CSCs/CICs were isolated from the ovarian carcinoma cell line HTBoA as aldehyde dehydrogenase 1 high (ALDH1(high)) population by the ALDEFLUOR assay. Histological examination of tumor tissues derived from ALDH1(high) cells revealed few fibrous stroma, whereas those derived from fibroblast-mixed ALDH1(high) cells showed abundant fibrous stroma formation. In vivo tumor-initiating capacity and in vitro sphere-forming capacity of ALDH1(high) cells were enhanced in the presence of fibroblasts. Gene expression analysis revealed that fibroblast-mixed ALDH1(high) cells had enhanced expression of fibroblast growth factor 4 (FGF4) as well as stemness-associated genes such as SOX2 and POU5F1. Sphere-forming capacity of ALDH1(high) cells was suppressed by small-interfering RNA (siRNA)-mediated knockdown of FGFR2, the receptor for FGF4 which was expressed preferentially in ALDH1(high) cells. Taken together, the results indicate that interaction of fibroblasts with ovarian CSCs/CICs enhanced tumor-initiating capacity and stem-like properties through autocrine and paracrine FGF4-FGFR2 signaling.

Genetic variants in the fibroblast growth factor pathway as potential markers of ovarian cancer risk, therapeutic response, and clinical outcome

BACKGROUND

The fibroblast growth factor (FGF) and FGF receptor (FGFR) axis plays a critical role in tumorigenesis, but little is known of its influence in ovarian cancer. We sought to determine the association of genetic variants in the FGF pathway with risk, therapeutic response, and survival of patients with ovarian cancer.

METHODS

We matched 339 non-Hispanic white ovarian cancer cases with 349 healthy controls and genotyped them for 183 single-nucleotide polymorphisms (SNPs) from 24 FGF (fibroblast growth factor) and FGFR (fibroblast growth factor receptor) genes. Genetic associations for the main effect, gene-gene interactions, and the cumulative effect were determined.

RESULTS

Multiple SNPs in the FGF-FGFR axis were associated with an increased risk of ovarian cancer. In particular, FGF1 [fibroblast growth factor 1 (acidic)] SNP rs7727832 showed the most significant association with ovarian cancer (odds ratio, 2.27; 95% CI, 1.31-3.95). Ten SNPs were associated with a reduced risk of ovarian cancer. FGF18 (fibroblast growth factor 18) SNP rs3806929, FGF7 (fibroblast growth factor 7) SNP rs9920722, FGF23 (fibroblast growth factor 23) SNP rs12812339, and FGF5 (fibroblast growth factor 5) SNP rs3733336 were significantly associated with a favorable treatment response, with a reduction of risk of nonresponse of 40% to 60%. Eleven SNPs were significantly associated with overall survival. Of these SNPs, FGF23 rs7961824 was the most significantly associated with improved prognosis (hazard ratio, 0.55; 95% CI, 0.39-0.78) and was associated with significantly longer survival durations, compared with individuals with the common genotype at this locus (58.1 months vs. 38.0 months, P = 0.005). Survival tree analysis revealed FGF2 rs167428 as the primary factor contributing to overall survival.

CONCLUSIONS

Significant associations of genetic variants in the FGF pathway were associated with ovarian cancer risk, therapeutic response, and survival. The discovery of multiple SNPs in the FGF-FGFR pathway provides a molecular approach for risk assessment, monitoring therapeutic response, and prognosis.

A novel regulation of PSMA and PSA expression by Q640X AR in 22Rv1 and LNCaP prostate cancer cells

We have investigated the expression of prostate-specific membrane antigen (PSMA) and prostate-specific antigen (PSA) transcripts in androgen-dependent (LNCaP) and androgen-independent (22Rv1) prostate cancer cell lines. We also enquired whether Q640X CTE-truncated androgen receptor (AR) has an impact on transcription of mRNA for PSMA and PSA in transfected androgen-sensitive prostate cancer LNCaP cells. Wild type LNCaP, 22Rv1 prostate cancer cells, prostate stromal cells (PrSC) and LNCaP cells transfected with p-Q640X AR, p-WT AR or p-C3 empty plasmids were studied. The expression of PSMA and PSA were detected by real-time PCR after transfection for 4 and 7 days. Expression of mRNAs for PSA was sixfold greater than PSMA in wild type LNCaP cells. In contrast, the wild type androgen refractory 22Rv1 cell line reacted almost exactly the opposite way reverse to LNCaP cells, since the transcription of mRNA for PSMA almost twofold greater than PSA. Non-transfected human PrSC responded similarly to PSMA mRNA and PSA mRNA was not detected in these cells. Q640X AR transfected LNCaP cells downregulated the expression of PSMA and PSA genes after 7 days. Our results demonstrate that Q640X mutated AR may have an important regulatory role in mediating the PSMA and PSA genes expression during the progression of prostate cancer from androgen-dependence to androgen-independence. Understanding their functional properties and mechanisms by which ARs involved in regulation of PSMA and PSA expression will allow the identification of new target therapies for the treatment of hormone-resistant prostate cancer.

The tumor microenvironment in prostate cancer: elucidating molecular pathways for therapy development

Mechanisms leading to the development of virulent prostate cancer are not confined to the cancer epithelial cell, but also involve the tumor microenvironment. Multiple signaling pathways exist between epithelial cells, stromal cells, and the extracellular matrix to support tumor progression from the primary site to regional lymph nodes and distant metastases. Prostate cancers preferentially metastasize to the skeleton, prompting considerable research effort into understanding the unique interaction between prostate cancer epithelial cells and the bone microenvironment. This effort has led to the discovery that signaling pathways involved in normal prostate and bone development become dysregulated in cancer. These pathways stimulate excessive cell growth and neovascularization, impart more invasive properties to epithelial cells, weaken antitumor immune surveillance, and promote the emergence of castrate-resistant disease. An improved understanding of the complex relationship between cancer epithelial cells and the organ-specific microenvironments with which they interact has created a powerful opportunity to develop novel therapies.

Small-molecule protein tyrosine kinase inhibitors for the treatment of metastatic prostate cancer

The microenvironment is critical to the growth of prostate cancer (PCa) in the bone. Thus, for clinical efficacy, therapies must target tumor-microenvironment interactions. Several protein tyrosine kinases have been implicated in the development and growth of PCa bone metastasis. In this review, specific protein tyrosine kinases that regulate these complex interactions, including PDGFR, the EGFR family, c-Src, VEGFR, IGF-1R, FGFR and c-Met will be discussed, with an emphasis on why these kinases are promising therapeutic targets for metastatic PCa treatment. For each of these kinases, small-molecule inhibitors have reached clinical trials. Current results of these trials and future prospects for the use of tyrosine kinase inhibitors for the treatment of PCa bone metastases are also discussed.

Allele-specific regulation of FGFR2 expression is cell type-dependent and may increase breast cancer risk through a paracrine stimulus involving FGF10

Introduction

SNPs rs2981582 and rs2981578, located in a linkage disequilibrium block (LD block) within intron 2 of the fibroblast growth factor receptor 2 gene (FGFR2), are associated with a mildly increased breast cancer risk. Allele-specific regulation of FGFR2 mRNA expression has been reported previously, but the molecular basis for the association of these variants with breast cancer has remained elusive to date.

Methods

mRNA levels of FGFR2 and three fibroblast growth factor genes (FGFs) were measured in primary fibroblast and epithelial cell cultures from 98 breast cancer patients and correlated to their rs2981578 genotype. The phosphorylation levels of downstream FGFR2 targets, FGF receptor substrate 2α (FRS2α) and extracellular signal-regulated kinases 1 and 2 (ERK1/2), were quantified in skin fibroblasts exposed to FGF2. Immunohistochemical markers for angiogenesis and lymphocytic infiltrate were semiquantitatively assessed in 25 breast tumors.

Results

The risk allele of rs2981578 was associated with increased FGFR2 mRNA levels in skin fibroblasts, but not in skin epithelial cell cultures. FGFR2 mRNA levels in skin fibroblasts and breast fibroblasts correlated strongly in the patients from whom both cultures were available. Tumor-derived fibroblasts expressed, on average, eight times more FGFR2 mRNA than the corresponding fibroblasts from normal breast tissue. Fibroblasts with higher FGFR2 mRNA expression showed more FRS2α and ERK1/2 phosphorylation after exposure to FGF2. In fibroblasts, higher FGFR2 expression correlated with higher FGF10 expression. In 25 breast tumors, no associations between breast tumor characteristics and fibroblast FGFR2 mRNA levels were found.

Conclusions

The influence of rs2981578 genotypes on FGFR2 mRNA expression levels is cell type-dependent. Expression differences correlated well with signaling levels of the FGFR2 pathway. Our results suggest that the increased breast cancer risk associated with SNP rs2981578 is due to increased FGFR2 signaling activity in stromal fibroblasts, possibly also involving paracrine FGF10 signaling.

Antitumor activity of a recombinant soluble ectodomain of mutant human fibroblast growth factor receptor-2 IIIc

The fibroblast growth factor (FGF) signaling pathway is a recognized target of cancer therapy. We have developed a strong inhibitor (S252W mutant soluble ectodomain of FGF recptor-2 IIIc, msFGFR2) that binds FGFs and blocks the activation of FGFRs. Thermodynamic binding studies indicated that msFGFR2 bound FGF-2 16.9 times as strongly as wild-type soluble FGFR2IIIc ectodomain (wsFGFR2). It successfully suppressed the growth, angiogenesis, and metastasis of two tumor cell lines in vitro and in vivo, and it potently inhibited cancer cell proliferation but not normal cell proliferation. Therefore, msFGFR2 is a useful probe for FGF-dependent signaling pathways and a potential broad-spectrum antitumor agent.

Personalized prostate cancer screening: improving PSA tests with genomic information

The use of a prostate-specific antigen (PSA) test to screen for prostate cancer is controversial because of its modest predictive value and the potential overdiagnosis and over-treatment of the disease. A research article in this issue of Science Translational Medicine describes single-nucleotide polymorphisms (SNPs) in or near six genes that are independently associated with serum PSA concentrations and that help to explain interindividual PSA variation. Three of these SNPs are also associated with prostate biopsy outcomes. These findings are an important step toward incorporating genetic markers into PSA screening, with the ultimate goal of devising personalized PSA tests for use in the clinic.

Basic FGF downregulates TSP50 expression via the ERK/Sp1 pathway

Previous studies demonstrated that the expression of testes-specific protease 50 (TSP50) was increased in breast cancer cells and that overexpression of TSP50 can promote tumorigenesis. Thus, it is important to identify the regulatory mechanisms of TSP50 for tumor therapy. In this study, we elucidated the mechanism underlying TSP50 downregulation by basic fibroblast growth factor (bFGF). We used MDA-MB-231 and HEK293T cell lines to address this issue. RT-PCR and promoter activity assays indicated that bFGF downregulates TSP50 expression via transcriptional activation. We next investigated the signaling pathway that mediated the effect of bFGF on TSP50 transcription, and identified that bFGF induced the phosphorylation of ERK and Sp1. An ERK inhibitor suppressed Sp1 phosphorylation and bFGF-reduced TSP50 expression at the mRNA level. In addition, the dominant negative (DN) mutants of ERK and Sp1 both suppressed the reduction of TSP50 by bFGF. Deletion and mutation analyses indicated that the Sp1 site, located within the +237/+239 region of the human TSP50 promoter, is the major responsive element for bFGF. Taken together, our results strongly suggest that bFGF mediates TSP50 downregulation by ERK activation, leading to the phosphorylation of Sp1 in this process.

Molecular signatures of the primitive prostate stem cell niche reveal novel mesenchymal-epithelial signaling pathways

Background

Signals between stem cells and stroma are important in establishing the stem cell niche. However, very little is known about the regulation of any mammalian stem cell niche as pure isolates of stem cells and their adjacent mesenchyme are not readily available. The prostate offers a unique model to study signals between stem cells and their adjacent stroma as in the embryonic prostate stem cell niche, the urogenital sinus mesenchyme is easily separated from the epithelial stem cells. Here we investigate the distinctive molecular signals of these two stem cell compartments in a mammalian system.

Methodology/Principal Findings

We isolated fetal murine urogenital sinus epithelium and urogenital sinus mesenchyme and determined their differentially expressed genes. To distinguish transcripts that are shared by other developing epithelial/mesenchymal compartments from those that pertain to the prostate stem cell niche, we also determined the global gene expression of epidermis and dermis of the same embryos. Our analysis indicates that several of the key transcriptional components that are predicted to be active in the embryonic prostate stem cell niche regulate processes such as self-renewal (e.g., E2f and Ap2), lipid metabolism (e.g., Srebp1) and cell migration (e.g., Areb6 and Rreb1). Several of the enriched promoter binding motifs are shared between the prostate epithelial/mesenchymal compartments and their epidermis/dermis counterparts, indicating their likely relevance in epithelial/mesenchymal signaling in primitive cellular compartments. Based on differential gene expression we also defined ligand-receptor interactions that may be part of the molecular interplay of the embryonic prostate stem cell niche.

Conclusions/Significance

We provide a comprehensive description of the transcriptional program of the major regulators that are likely to control the cellular interactions in the embryonic prostatic stem cell niche, many of which may be common to mammalian niches in general. This study provides a comprehensive source for further studies of mesenchymal/epithelial interactions in the prostate stem cell niche. The elucidation of pathways in the normal primitive niche may provide greater insight into mechanisms subverted during abnormal proliferative and oncogenic processes. Understanding these events may result in the development of specific targeted therapies for prostatic diseases such as benign prostatic hypertrophy and carcinomas.

A dietary tomato supplement prevents prostate cancer in TRAMP mice

Transgenic adenocarcinoma of the mouse prostate (TRAMP) is a model for progressive prostate cancer that mirrors the stages of the human form. In this study, the effects of a diet enriched with processed whole tomatoes on survival, tumorigenesis, and progression of prostate cancer, and the antioxidant and inflammatory status of TRAMP mice were investigated. Tomato diet significantly increased overall survival (P < 0.01), delayed progression from prostatic intraepithelial neoplasia to adenocarcinoma, and decreased the incidence of poorly differentiated carcinoma. Biochemical data disclosed an increase in serum antioxidant activity and a reduction of serum inflammation/angiogenesis biomarkers of particular importance in prostate carcinogenesis.

A new therapy paradigm for prostate cancer founded on clinical observations

Efficacy equivalent to that reported in other common adult solid tumors considered to be chemotherapy-sensitive has been reported with Docetaxel in patients with castrate-resistant prostate cancer. However, in contrast to other cancers, the expected increase in efficacy with the use of chemotherapy in earlier disease states has not been reported to date in prostate cancer. On the basis of these observations, we speculated that the therapy development paradigm used successfully in other cancers may not apply to the majority of prostate cancers. Several lines of supporting clinical and experimental observations implicate the tumor microenvironment in prostate carcinogenesis and resistance to therapy. We conclude that a foundation to guide the development of therapy for prostate cancer is required. The therapy paradigm we propose accounts for the central role of the tumor microenvironment in bone and, if correct, will lead to microenvironment-targeted therapy.

Fibroblast growth factor signalling: from development to cancer

Fibroblast growth factors (FGFs) and their receptors control a wide range of biological functions, regulating cellular proliferation, survival, migration and differentiation. Although targeting FGF signalling as a cancer therapeutic target has lagged behind that of other receptor tyrosine kinases, there is now substantial evidence for the importance of FGF signalling in the pathogenesis of diverse tumour types, and clinical reagents that specifically target the FGFs or FGF receptors are being developed. Although FGF signalling can drive tumorigenesis, in different contexts FGF signalling can mediate tumour protective functions; the identification of the mechanisms that underlie these differential effects will be important to understand how FGF signalling can be most appropriately therapeutically targeted.

Chromosome 8p as a potential hub for developmental neuropsychiatric disorders: implications for schizophrenia, autism and cancer

Defects in genetic and developmental processes are thought to contribute susceptibility to autism and schizophrenia. Presumably, owing to etiological complexity identifying susceptibility genes and abnormalities in the development has been difficult. However, the importance of genes within chromosomal 8p region for neuropsychiatric disorders and cancer is well established. There are 484 annotated genes located on 8p; many are most likely oncogenes and tumor-suppressor genes. Molecular genetics and developmental studies have identified 21 genes in this region (ADRA1A, ARHGEF10, CHRNA2, CHRNA6, CHRNB3, DKK4, DPYSL2, EGR3, FGF17, FGF20, FGFR1, FZD3, LDL, NAT2, NEF3, NRG1, PCM1, PLAT, PPP3CC, SFRP1 and VMAT1/SLC18A1) that are most likely to contribute to neuropsychiatric disorders (schizophrenia, autism, bipolar disorder and depression), neurodegenerative disorders (Parkinson's and Alzheimer's disease) and cancer. Furthermore, at least seven nonprotein-coding RNAs (microRNAs) are located at 8p. Structural variants on 8p, such as copy number variants, microdeletions or microduplications, might also contribute to autism, schizophrenia and other human diseases including cancer. In this review, we consider the current state of evidence from cytogenetic, linkage, association, gene expression and endophenotyping studies for the role of these 8p genes in neuropsychiatric disease. We also describe how a mutation in an 8p gene (Fgf17) results in a mouse with deficits in specific components of social behavior and a reduction in its dorsomedial prefrontal cortex. We finish by discussing the biological connections of 8p with respect to neuropsychiatric disorders and cancer, despite the shortcomings of this evidence.