Expression of keratinocyte growth factor and its receptor in human breast cancer: its inhibitory role in the induction of apoptosis possibly through the overexpression of Bcl-2

Depletion of high-mobility group box 2 causes seminiferous tubule atrophy via aberrant expression of androgen and estrogen receptors in mouse testis†

High-mobility group box 2, a chromatin-associated protein that interacts with deoxyribonucleic acid, is implicated in multiple biological processes, including gene transcription, replication, and repair. High-mobility group box 2 is expressed in several tissues, including the testis; however, its functional role is largely unknown. Here, we elucidated the role of high-mobility group box 2 in spermatogenesis. Paraffin-embedded testicular tissues were obtained from 8-week-old and 1-year-old wild-type and knock-out mice. Testis weight and number of seminiferous tubules were decreased, whereas atrophic tubules were increased in high-mobility group box 2-depleted mice. Immunohistochemistry revealed that atrophic tubules contained Sertoli cells, but not germ cells. Moreover, decreased cell proliferation and increased apoptosis were demonstrated in high-mobility group box 2-depleted mouse testis. To elucidate the cause of tubule atrophy, we examined the expression of androgen and estrogen receptors, and the results indicated aberrant expression of androgen receptor and estrogen receptor alpha in Sertoli and Leydig cells. Southwestern histochemistry detected decreased estrogen response element-binding sites in high-mobility group box 2-depleted mouse testis. High-mobility group box 1, which has highly similar structure and function as high-mobility group box 2, was examined by immunohistochemistry and western blotting, which indicated increased expression in testis. These findings indicate a compensatory increase in high-mobility group box 1 expression in high-mobility group box 2 knock-out mouse testis. In summary, depletion of high-mobility group box 2 induced aberrant expression of androgen receptor and estrogen receptor alpha, leading to decreased germ cell proliferation and increased apoptosis which resulted in focal seminiferous tubule atrophy.

Photodynamic Therapy Using a Novel Phosphorus Tetraphenylporphyrin Induces an Anticancer Effect via Bax/Bcl-xL-related Mitochondrial Apoptosis in Biliary Cancer Cells

Photodynamic therapy (PDT) uses photosensitizer activation by light of a specific wavelength, and is a promising treatment for various cancers; however, the detailed mechanism of PDT remains unclear. Therefore, we investigated the anticancer effect of PDT using a novel phosphorus tetraphenylporphyrin (Ptpp) in combination with light emitting diodes (Ptpp-PDT) in the NOZ human biliary cancer cell line. Cell viability and apoptosis were examined by MTT assay, flow cytometry and TUNEL assay for 24 hr after Ptpp-PDT. MitoTracker and JC-1 were used as markers of mitochondrial localization and membrane potential. The levels of mitochondrial oxidative phosphorylation (OXPHOS) complexes, Bcl-2 family proteins, cytochrome c and cleaved caspase-3 were examined by western blotting and immunohistochemistry. The results revealed that Ptpp localized to mitochondria, and that Ptpp-PDT efficiently decreased cell viability in a dose- and time-dependent manner. JC-1 and OXPHOS complexes decreased, but apoptotic cells increased from 6 to 24 hr after Ptpp-PDT. A decrease in Bcl-xL and increases in Bax, cytochrome c and cleaved caspase-3 were also found from 6 to 24 hr after Ptpp-PDT. Based on these results, we conclude that Ptpp-PDT induces anticancer effects via the mitochondrial apoptotic pathway by altering the Bax/Bcl-xL ratio, and could be an effective treatment for human biliary cancer.

The proliferative and anti-apoptosis functions of KGF/KGFR contributes to bronchial epithelial repair in asthma

This study aimed to investigate the effect of keratinocyte growth factor (KGF) on the apoptosis, proliferation, damage repair, intercellular adhesion, and inflammatory cytokine release of cultured 16HBE 14o-bronchial ECs in vitro. Bronchial epithelial cells (ECs) from all subjects were obtained by bronchoscopic brushing. The expression levels of KGF and its receptor KGFR in collected cells were determined using RT-qPCR and Western blotting. The apoptosis and adhesion molecules expression by KGF administration were determined using flow cytometry and Western blotting. This occurred when 16HBE 14o-cell lines cultured and were exposed to interferon-γ (IFN-γ) and tumor necrosis factor-alpha (TNF-α) in vitro. The role of KGF on proliferation and damage repair were analyzed using CCK-8, EdU and wound closure assays after 16HBE 14o-cells were scraped. The effect of KGF on the release of inflammation related cytokines by damaged ECs was measured using ELISA kits. Compared with healthy controls, the KGF and KGFR expression and apoptosis significantly increased in collected cells from asthma patients. In vitro, treatment of KGF may limit IFN-γ and TNF-α induced apoptosis by inhibiting apoptosis-associated markers in the TNF signaling pathway. Besides, KGF could limit the release of TSLP, IL-25 and IL-33 by damaged 16HBE 14o-cells. On the contrary, KGF could promote the intercellular adhesion and wound closure of cultured 16HBE 14o-cells via the increased expression level of intercellular junction proteins ICAM-1, β-catenin, E-cad, and Dsc3. In conclusion, KGF and KGFR may help bronchial ECs repair in asthma via the inhibition apoptosis of ECs while the promotion of proliferation and migration of ECs.

The HDAC Inhibitor, SAHA, Combined with Cisplatin Synergistically Induces Apoptosis in Alpha-fetoprotein-producing Hepatoid Adenocarcinoma Cells

Hepatoid adenocarcinoma (HAC) is a rare and aggressive gastrointestinal tract cancer that is characterized by hepatic differentiation and production of alpha-fetoprotein (AFP). Cisplatin is mainly used to treat HAC, but the efficacy is poor. Recently, the histone deacetylase inhibitor, suberoylanilide hydroxamic acid (SAHA), was approved as an anticancer agent. In this study, we investigated the anticancer effect of SAHA in combination with cisplatin in VAT-39 cells, a newly established HAC cell line. Cell viability and apoptosis were examined by MTT assay, flow cytometry and TUNEL assay. Expression of H3S10, cleaved caspase-3, Bax, and Bcl-2 were evaluated by immunohistochemistry and western blotting. AFP levels were examined in VAT-39 cells and culture medium. Combined treatment with cisplatin and SAHA efficiently inhibited cell proliferation and decreased cell viability. Apoptotic cells, but not necrotic cells, were significantly increased following the combined treatment, and an increase in the Bax/Bcl-2 ratio indicated that the combination of cisplatin and SAHA induced apoptosis through the mitochondrial pathway. VAT-39 cells treated with cisplatin and SAHA also partially lost their main characteristic of AFP production. We conclude that cisplatin and SAHA have a synergistic anticancer effect of inducing apoptosis, and that this combination treatment may be effective for HAC.

Estrogen Regulates Mitochondrial Morphology through Phosphorylation of Dynamin-related Protein 1 in MCF7 Human Breast Cancer Cells

Estrogen affects mitochondrial function in various tissues, but the precise mechanism remains unclear. We, therefore investigated the effect on estrogen-regulated mitochondrial morphology by dynamin-related protein 1 (Drp1) and its Ser616-phosphorylated derivative (pDrp1^Ser616) are involved in mitochondrial fission. MCF7 human breast cancer cells were treated with 17β-estradiol (E₂), an estrogen receptor (ER) α and β antagonist (ICI 182, 780), an ERα antagonist (MPP), and an ERβ antagonist (PHTPP) for 24 hr. The expression of Drp1 and pDrp1^Ser616 was analyzed by western blotting and immunohistochemistry. Mitochondrial morphology was analyzed by transmission electron microscopy (TEM). In control cells, Drp1 was detected in the cytoplasm of all cells while pDrp1 was observed in the cytoplasm of 3.4 ± 1.0% of the total population. After E₂ treatment, pDrp1^Ser616-positive cells comprised 30.6 ± 5.6% of the total population, 10.5 ± 1.7% after E₂ + ICI treatment, 12.4 ± 4.2% after E₂ + MPP treatment, and 24.0 ± 2.2% after E₂ + PHTPP treatment. In ERα knockdown MCF7 cells, pDrp1 expression was decreased after E₂ treatment compared to E₂-treated wild type cells. Tubular pattern mitochondria were found in the control cells but the number of short and small pattern mitochondria (< 0.5 μm²) was significantly increased after E₂ treatment (as observed by TEM). We, therefore concluded that the phosphorylation of Drp1 is important for E₂-dependent mitochondrial morphological changes through ERα.

Arsenic trioxide induces ROS activity and DNA damage, leading to G0/G1 extension in skin fibroblasts through the ATM-ATR-associated Chk pathway

Arsenic (As) toxicity is a global health problem, affecting millions of people. Exposure to arsenic, mostly via drinking water, has been associated with cancer of skin, lungs, and blood, in addition to several kinds of skin lesions. The present study focused on the effect of arsenic trioxide (As₂O₃) on normal skin fibroblast cells. Specifically, the effect of As₂O₃ on ROS generation and oxidative stress was investigated. Proteins involved in the DNA damage signaling pathway and cell cycle were also studied. As₂O₃ induced the generation of intracellular ROS. Immunohistochemistry analysis revealed a dose-dependent increase in the number of 8-OHdG-positive cells, an indication of oxidative stress. Cell cycle analysis by flow cytometry demonstrated that As₂O₃ caused a significant percentage of cells to accumulate in the G0/G1 phase with a concomitant reduction in the S phase. Increases in the activated forms of DNA damage signaling proteins, ATM and ATR, and their effector molecules, Chk2 and p53, were also observed. In addition, expression of oncogene p21 was also increased. The study shows that exposure of normal skin fibroblast cells to As₂O₃ could lead to cell cycle arrest through ATM/ATR and DNA damage signaling pathways. In conclusion, we report here that arsenic trioxide increases cellular oxidative stress leading to shift in cell cycle and leads to DNA damage through ATM/ATR and the CHK-dependent signaling pathway.

Differential immunohistochemical expression profiles of perlecan-binding growth factors in epithelial dysplasia, carcinoma in situ, and squamous cell carcinoma of the oral mucosa

The intercellular deposit of perlecan, a basement-membrane type heparan sulfate proteoglycan, is considered to function as a growth factor reservoir and is enhanced in oral epithelial dysplasia and carcinoma in situ (CIS). However, it remains unknown which types of growth factors function in these perlecan-enriched epithelial conditions. The aim of this study was to determine immunohistochemically which growth factors were associated with perlecan in normal oral epithelia and in different epithelial lesions from dysplasia and CIS to squamous cell carcinoma (SCC). Eighty-one surgical tissue specimens of oral SCC containing different precancerous stages, along with ten of normal mucosa, were examined by immunohistochemistry for growth factors. In normal epithelia, perlecan and growth factors were not definitely expressed. In epithelial dysplasia, VEGF, SHH, KGF, Flt-1, and Flk-1were localized in the lower half of rete ridges (in concordance with perlecan, 33-100%), in which Ki-67 positive cells were densely packed. In CIS, perlecan and those growth factors/receptors were more strongly expressed in the cell proliferating zone (63-100%). In SCC, perlecan and KGF disappeared from carcinoma cells but emerged in the stromal space (65-100%), while VEGF, SHH, and VEGF receptors remained positive in SCC cells (0%). Immunofluorescence showed that the four growth factors were shown to be produced by three oral SCC cell lines and that their signals were partially overlapped with perlecan signals. The results indicate that perlecan and its binding growth factors are differentially expressed and function in specific manners before (dysplasia/CIS) and after (SCC) invasion of dysplasia/carcinoma cells.

Hyperbaric Oxygen Therapy Suppresses Apoptosis and Promotes Renal Tubular Regeneration After Renal Ischemia/Reperfusion Injury in Rats

BACKGROUND

Renal ischemia/reperfusion (I/R) injury remains a major cause of acute kidney injury (AKI), in addition to I/R injury-induced tissue inflammation, necrosis and apoptosis. Hyperbaric oxygen therapy (HBO) is defined as a treatment in which a patient is intermittently exposed to 100% oxygen pressurized to a pressure above sea level (> 2.0 atmospheres absolute (ATA), 1.0 ATA = 760 mmHg). It has been used in a number of medical conditions with a proven efficacy in a limited number of disorders. However, the effects of HBO therapy on apoptosis and proliferative activity after I/R injury have not been fully understood.

OBJECTIVES

We studied the possible beneficial effects of HBO therapy on apoptosis and tubular cell regeneration after renal I/R injury in rats.

MATERIALS AND METHODS

Sprague-Dawley (SD) rats were randomized into three groups: Sham (Sham-operated rats); I/R (animals submitted to I/R); and I/R + HBO (I/R rats exposed to HBO). Tubular cell apoptosis was confirmed by DNA laddering and the terminal deoxynucleotidyl transferase-mediated uridine triphosphate nick end labeling (TUNEL) assay. Cellular proliferation activity was determined using the anti-Ki-67 antibody.

RESULTS

A significant decrease in apoptotic cells and increase in proliferative reaction were observed in the I/R + HBO group compared to the I/R group.

CONCLUSIONS

We demonstrated that HBO suppressed apoptosis, which caused inflammation after renal I/R, and promoted tubular cell regeneration. HBO has protective effects against AKI caused by renal I/R through the inhibition of apoptosis.

Keratinocyte growth factor receptor: a therapeutic target in solid cancer

INTRODUCTION

The treatment effects of advanced solid cancer are unsatisfactory, and novel therapeutic approaches are much needed. Keratinocyte growth factor receptor (KGFR) is a receptor tyrosine kinase that is primarily localized on epithelial cells. KGFR may play important roles in epithelial cell proliferation and differentiation, epithelial wound repair, embryonic development, immunity, tumor formation and development.

AREAS COVERED

This review summarizes the expression, function and mechanism of KGFR in solid cancer, and analyzes its value for the cancer therapy. Furthermore, this study discusses the limitations of KGFR-based therapy, and envisages future developments in the clinical applications of KGFR.

EXPERT OPINION

KGFR may function as an ideal therapeutic target for solid cancer. Continued basic investigation of KGFR-mediated pathways will push insight into the novel strategies of target therapy. More in vivo studies and clinical trials should be performed to promote the translational bridging of the latest research into clinical application.

A phase II, open-label study of ramucirumab in combination with paclitaxel and carboplatin as first-line therapy in patients with stage IIIB/IV non-small-cell lung cancer

INTRODUCTION

The objective of this study was to determine whether the addition of ramucirumab to first-line paclitaxel-carboplatin chemotherapy in patients with advanced non-small-cell lung cancer (NSCLC) resulted in a 6-month progression-free survival (PFS) rate that compares favorably with the historic rate for bevacizumab combined with paclitaxel-carboplatin in this patient population.

METHODS

In this phase II, single-arm, open-label, multicenter study, 40 patients with advanced NSCLC received ramucirumab (10 mg/kg intravenous [IV]) followed by paclitaxel (200 mg/m IV) and carboplatin area under the curve = 6 on day 1 every 21 days as first-line therapy. Therapy continued for up to six cycles. Patients not experiencing withdrawal criteria may have continued ramucirumab monotherapy every 3 weeks. The primary endpoint was PFS at 6 months, with 80% power to detect a 6-month PFS rate of at least 55%.

RESULTS

The 6-month PFS rate was 59.0% and the objective response rate was 55.0%. The most common treatment-related adverse events were fatigue, peripheral neuropathy, nausea, epistaxis, and myalgia. Single-nucleotide polymorphism (SNP) rs2981582 on the FGFR-2gene had significant associations with improved overall survival, PFS, and best overall response (p values without multiplicity adjustment were 0.0059, 0.0429, and 0.0392, respectively).

CONCLUSION

Ramucirumab in combination with paclitaxel-carboplatin resulted in a 6-month PFS rate and safety profile that compared favorably with the historical control. In addition, no deaths were associated with this treatment. Furthermore, we describe an association of SNP on FGFR-2 gene with survival and response. These findings warrant further clinical investigation in patients with NSCLC.

Palifermin for the protection and regeneration of epithelial tissues following injury: new findings in basic research and pre-clinical models

Keratinocyte growth factor (KGF) is a paracrine-acting epithelial mitogen produced by cells of mesenchymal origin, that plays an important role in protecting and repairing epithelial tissues. Pre-clinical data initially demonstrated that a recombinant truncated KGF (palifermin) could reduce gastrointestinal injury and mortality resulting from a variety of toxic exposures. Furthermore, the use of palifermin in patients with hematological malignancies reduced the incidence and duration of severe oral mucositis experienced after intensive chemoradiotherapy. Based upon these findings, as well as the observation that KGF receptors are expressed in many, if not all, epithelial tissues, pre-clinical studies have been conducted to determine the efficacy of palifermin in protecting different epithelial tissues from toxic injury in an attempt to model various clinical situations in which it might prove to be of benefit in limiting tissue damage. In this article, we review these studies to provide the pre-clinical background for clinical trials that are described in the accompanying article and the rationale for additional clinical applications of palifermin.

Functional analysis of a breast cancer-associated FGFR2 single nucleotide polymorphism using zinc finger mediated genome editing

Genome wide association studies have identified single nucleotide polymorphisms (SNP) within fibroblast growth factor receptor 2 (FGFR2) as one of the highest ranking risk alleles in terms of development of breast cancer. The potential effect of these SNPs, in intron two, was postulated to be due to the differential binding of cis-regulatory elements, such as transcription factors, since all the SNPs in linkage disequilibrium were located in a regulatory DNA region. A Runx2 binding site was reported to be functional only in the minor, disease associated allele of rs2981578, resulting in increased expression of FGFR2 in cancers from patients homozygous for that allele. Moreover, the increased risk conferred by the minor FGFR2 allele associates most strongly in oestrogen receptor alpha positive (ERα) breast tumours, suggesting a potential interaction between ERα and FGFR signalling. Here, we have developed a human cell line model system to study the effect of the putative functional SNP, rs2981578, on cell behaviour. MCF7 cells, an ERα positive breast cancer cell line homozygous for the wild-type allele were edited using a Zinc Finger Nuclease approach. Unexpectedly, the acquisition of a single risk allele in MCF7 clones failed to affect proliferation or cell cycle progression. Binding of Runx2 to the risk allele was not observed. However FOXA1 binding, an important ERα partner, appeared decreased at the rs2981578 locus in the risk allele cells. Differences in allele specific expression (ASE) of FGFR2 were not observed in a panel of 72 ERα positive breast cancer samples. Thus, the apparent increased risk of developing ERα positive breast cancer seems not to be caused by rs2981578 alone. Rather, the observed increased risk of developing breast cancer might be the result of a coordinated effect of multiple SNPs forming a risk haplotype in the second intron of FGFR2.

Clinicopathological significance of expression of keratinocyte growth factor protein in pancreatic ductal adenocarcinoma

AIM: To assess the clinicopathological significance of expression of keratinocyte growth factor (KGF) protein in pancreatic ductal adenocarcinoma (PDAC).

METHODS: The expression of KGF protein in 51 paraffin-embedded PDAC specimens and matched tumor-adjacent pancreatic tissue specimens was detected by immunohistochemistry. The relationship between KGF protein expression and clinicopathological characteristics of PDAC was analyzed.

RESULTS: The expression of KGF protein was significantly higher in PDAC than in matched non-cancerous pancreatic tissues (Z = -4.766, P < 0.001). The expression of KGF protein was positively correlated with hepatic metastasis (χ² = 4.113, P < 0.05). Mean survival time was shorter in KGF (+) patients than in KGF (-) ones (384 d vs 621 d).

CONCLUSION: Expression of KGF is up-regulated in PDAC. KGF up-regulation may be related with hepatic metastasis of PDAC. Mean survival time is shorter in KGF (+) patients than in KGF (-) ones.

Association between rs2981582 polymorphism in the FGFR2 gene and the risk of breast cancer in Mexican women

BACKGROUND AND AIMS

The rs2981582 single nucleotide polymorphism in the fibroblast growth factor receptor 2 gene has been consistently associated with an increased risk of breast cancer. We evaluated the effect of rs2981582 polymorphism in the FGFR2 gene on the risk of breast cancer and its interaction with non-genetic risk factors.

METHODS

A population-based case-control study was conducted in Mexico. Data from 687 cases and 907 controls were analyzed.

RESULTS

The T allele of the rs2981582 polymorphism was associated with an increased risk of breast cancer (ORper allele = 1.24, 95% CI 1.06-1.46). There was also an interaction between this polymorphism and alcohol consumption (p = 0.043). The effect of alcohol consumption on the risk of breast cancer varied according to the allelic variants of the rs2981582 polymorphism in the FGFR2 gene: OR = 3.97 (95% CI 2.10-7.49), OR = 2.01 (95% CI 1.23-3.29) and OR = 1.21 (95% CI 0.48-3.05) for genotypes CC, CT and TT, respectively.

CONCLUSIONS

This is the first study exploring the association between rs2981582 polymorphism in the FGFR2 gene and breast cancer risk in Mexican women. The interaction found may be of great public health interest because alcohol consumption is a modifiable breast cancer risk factor. Therefore, replication of this finding is of foremost importance.

Role of KGF in regulating biological behavior of pancreatic cancer cells

AIM: To examine the role of keratinocyte growth factor (KGF) in regulating the biological behavior of pancreatic cancer cells.

METHODS: Immunoblotting (IB) and polymerase chain reaction (PCR) were used to detect the protein and mRNA levels of KGF and its receptor in six pancreatic cancer cell lines (CaPan-2, BxPc-3, MIAPaca-2, ASPc-1, SW-1990, and PANC-2). MTT, migration and invasion assays were used to detect the role of KGF in regulating cell proliferation, migration and invasion in pancreatic cancer cell line BxPC-3.

RESULTS: The protein level of KGF was lower in BxPC-3 cells than in other five pancreatic cancer cell lines, while the mRNA level of KGFR was higher in BxPC-3 cells than in other five cell lines. KGF could significantly promote BxPc-3 cell proliferation, migration and invasion (all P < 0.01).

CONCLUSION: KGF can promote cell proliferation, migration and invasion in some pancreatic cancer cell lines.

Expression and functions of fibroblast growth factor 10 in the mouse mammary gland

Fibroblast growth factor 10 (FGF10) is important as a mesenchymal mediator of epithelial growth and morphogenesis. In this study, the expression and localization of the FGF10 protein were detected by laser scanning confocal microscopy during mouse postnatal mammary gland development. Mammary explants were cultured to investigate the functions of FGF10. The results revealed that FGF10 localizes mainly in the mesenchyme near the ductal epithelial cells and the alveolar epithelial cells of the mammary gland. Peak FGF10 expression levels were observed at lactation day 10. FGF10 induced FGFR2-IIIb expression in the mammary epithelium, except in virgin or pregnant mice. FGF10 promoted the proliferation of mammary gland epithelial cells and reduced apoptosis. FGF10 is important during the mouse mammary gland growth, development, and reconstruction, and its effects are mediated by FGFR2-IIIb.

Associations of polymorphisms in the genes of FGFR2, FGF1, and RBFOX2 with breast cancer risk by estrogen/progesterone receptor status

Genetic polymorphisms of fibroblast growth factor receptor 2 (FGFR2) have been demonstrated to be associated with breast cancer risk, presumably through elevation of FGFR2 expression. Fibroblast growth factor 1 (FGF1) and RNA binding protein fox-1 homolog 2 (RBFOX2), which are functionally related to FGFR2, may also associate with breast cancer risk. We investigated the associations between breast cancer risk and the polymorphisms of FGFR2 rs2981582, FGF1 rs250108, and RBFOX2 rs2051579 among 839 incident breast cancer cases and 863 age-matched controls in the Guangzhou Breast Cancer Study. Stratified odds ratios (ORs) and 95% confidence intervals (CIs) were calculated by estrogen receptor (ER)/progesterone receptor (PR) status using multivariate logistic regression. FGFR2 rs2981582 was confirmed to be significantly associated with the risk of ER-positive but not ER-negative breast cancer. In contrast, FGF1 rs250108 was significantly associated with the risk of ER-negative breast cancer (OR (95% CI) = 1.68 (1.20-2.35) for CT + TT vs. CC genotype) but not ER-positive breast cancer. CA + AA genotypes at RBFOX2 rs2051579 were associated with a reduced risk of ER-negative (0.71 (0.52-0.97)) but not ER-positive breast cancer compared to the CC genotype. Similar results were observed when differentiating breast cancer cases by PR status. Neither of the pairs between the three SNPs had a significant interaction on breast cancer risk. Our findings show a suggestively stronger association between FGFR2 rs2981582 and ER-positive breast cancer risk and suggest a greater association of FGF1 rs250108 and RBFOX2 rs2051579 with ER-negative compared to ER-positive breast cancer.

Potential dual role of KGF/KGFR as a target option in novel therapeutic strategies for the treatment of cancers and mucosal damages

INTRODUCTION

Keratinocyte growth factor (KGF) and its receptor KGFR play a pivotal role in regulating cell proliferation, migration, differentiation and survival, in response to injury and tissue repair. Altered expression of this pathway in cancer opened the way to the development of targeted therapy to achieve KGFR inhibition. Nevertheless, KGF administration has been demonstrated to ameliorate oral mucositis resulting from chemoradiotherapy, besides protecting epithelial cells against radiation-induced damage.

AREAS COVERED

This review focuses on the potential therapeutic interest of KGF/KGFR in two different areas: selective inhibition of KGFR signaling for the treatment of cancers characterized by upregulation of this pathway and administration of KGF to protect epithelial cells from induced damage. The review presents an overview of therapeutic strategies in both directions.

EXPERT OPINION

KGF/KGFR signaling can contribute to enhancing the malignant potential of epithelial cells and to promoting tumorigenesis. On the other hand, the therapeutic use of KGF in cancer patients provides epithelial protection, reducing chemotherapy side effects. FGFRs have become attractive antitumor targets and various inhibitors have been used to contrast tumor cell growth. The identification of KGFR-specific molecules might represent a promising therapeutic strategy that could increase the window of available agents and treatment methods.

Amplification of thymosin beta 10 and AKAP13 genes in metastatic and aggressive papillary thyroid carcinomas

Papillary thyroid carcinoma (PTC) is the most common well-differentiated thyroid cancer. Although the great majority of the cases exhibit an indolent clinical course, some of them develop local invasion with distant metastasis, and a few cases transform into undifferentiated/anaplastic thyroid carcinoma with a rapidly lethal course. To identify gene copy number alterations predictive of metastatic potential or aggressive transformation, array-based comparative genomic hybridization (CGH-array) was performed in 43 PTC cases. Formalin-fixed and paraffin-embedded samples from primary tumours of 16 cases without metastasis, 14 cases with only regional lymph node metastasis, and 13 cases with distant metastasis, recurrence or extrathyroid extension were analysed. The CGH-array and confirmatory quantitative real-time PCR results identified the deletion of the EIF4EBP3 and TRAK2 gene loci, while amplification of thymosin beta 10 (TB10) and Tre-2 oncogene regions were observed as general markers for PTC. Although there have been several studies implicating TB10 as a specific marker based on gene expression data, our study is the first to report on genomic amplification. Although no significant difference could be detected between the good and bad prognosis cases in the A-kinase anchor protein 13 (AKAP13) gene region, it was discriminative markers for metastasis. Amplification in the AKAP13 region was demonstrated in 42.9% and 15.4% of the cases with local or with distant metastasis, respectively, while no amplification was detected in non-metastatic cases. AKAP13 and TB10 regions may represent potential new genomic markers for PTC and cancer progression.

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.

Implication of heat shock factors in tumorigenesis: therapeutical potential

Heat Shock Factors (HSF) form a family of transcription factors (four in mammals) which were named according to the discovery of their activation by a heat shock. HSFs trigger the expression of genes encoding Heat Shock Proteins (HSPs) that function as molecular chaperones, contributing to establish a cytoprotective state to various proteotoxic stresses and in pathological conditions. Increasing evidence indicates that this ancient transcriptional protective program acts genome-widely and performs unexpected functions in the absence of experimentally defined stress. Indeed, HSFs are able to re-shape cellular pathways controlling longevity, growth, metabolism and development. The most well studied HSF, HSF1, has been found at elevated levels in tumors with high metastatic potential and is associated with poor prognosis. This is partly explained by the above-mentioned cytoprotective (HSP-dependent) function that may enable cancer cells to adapt to the initial oncogenic stress and to support malignant transformation. Nevertheless, HSF1 operates as major multifaceted enhancers of tumorigenesis through, not only the induction of classical heat shock genes, but also of “non-classical” targets. Indeed, in cancer cells, HSF1 regulates genes involved in core cellular functions including proliferation, survival, migration, protein synthesis, signal transduction, and glucose metabolism, making HSF1 a very attractive target in cancer therapy. In this review, we describe the different physiological roles of HSFs as well as the recent discoveries in term of non-cogenic potential of these HSFs, more specifically associated to the activation of “non-classical” HSF target genes. We also present an update on the compounds with potent HSF1-modulating activity of potential interest as anti-cancer therapeutic agents.

Expression of keratinocyte growth factor and its receptor in rat tracheal cartilage: possible involvement in wound healing of the damaged cartilage

Keratinocyte growth factor (KGF) is involved in the development and regeneration of a variety of tissues. To clarify the role of KGF in cartilage wound healing, we examined the expression of KGF and its receptor (KGFR) immunohistochemically in the wound healing area of rat tracheal cartilage, and the direct effect of recombinant KGF on the proliferation and differentiation of primary cultures of rat chondrocytes. KGF was found in the cytoplasm of both chondrocytes and perichondrial cells. On the other hand, KGFR was detected only in the plasma membrane of chondrocytes. Although the expression of KGF was similar in the cartilage and perichondrial area before and after injury, KGFR expression was induced after injury and limited to proliferating chondrocytes. The staining pattern of KGF and KGFR was same in the mature and the immature rat tracheal cartilage. Moreover, in vitro experiments using primary cultured chondrocytes revealed that KGF at 200 ng/ml significantly increased the number of chondrocytes (~1.5-fold), and significantly reduced acid mucopolysaccharide production. These results indicate that KGF stimulates chondrocyte proliferation, suggesting that KGF could therapeutically modulate the wound healing process in the tracheal cartilage.

Combined treatment with cytoprotective agents and radiotherapy

Radiotherapy is associated with several toxicities affecting healthy tissues. One of the strategies aimed at decreasing radiation toxicity is the use of radioprotective agents, such as amifostine and palifermin, or factors stimulating hemopoetic stem cells (colony stimulating factors, CSFs): granulocyte-CSF, granulocyte macrophage-CSF and recombinant erythropoetins. The potential beneficial effect of these substances demonstrated in preclinical in vitro and in vivo studies led to numerous clinical trials. This review addresses the current experience on the use of cytoprotective agents in combination with radiotherapy, with particular focus on the safety of these approaches. Despite a relatively large body of literature data, the role of cytoprotective agents combined with radiotherapy remains controversial. Overall, their use in this application is still limited due to modest radioprotective effect for normal tissues, potential risk of tumor protection and increased treatment toxicity. The use of erythropoetins in combination with radiotherapy should generally be discouraged, whereas the safe and effective application of other agents warrants further investigations.

Genetic susceptibility loci for breast cancer by estrogen receptor status

Breast cancer is a heterogeneous disease, and risk factors could be differentially associated with the development of distinct tumor subtypes that manifest different biological behavior and progression. In support of this view, there is growing evidence that known breast cancer risk factors vary by hormone receptor status and perhaps other pathologic characteristics of disease. Recent work from large consortial studies has led to the discovery of novel breast cancer susceptibility loci in genic (CASP8, FGFR2, TNRC9, MAP3K1, LSP1) and nongenic regions (8q24, 2q35, 5p12) of the genome, and to the finding of substantial heterogeneity by tumor characteristics. In particular, susceptibility loci in FGFR2, TNRC9, 8q24, 2q35, and 5p12 have stronger associations for estrogen receptor-positive (ER+) disease than estrogen receptor-negative (ER -) disease. These findings suggest that common genetic variants can influence the pathologic subtype of breast cancer, and provide further support for the hypothesis that ER+ and ER(-) disease result from different etiologic pathways. Current studies had limited power to detect susceptibility loci for less common tumor subtypes, such as ER(-) disease including triple-negative and basal-like tumors. Ongoing work targeting uncommon subtypes is likely to identify additional tumor-specific susceptibility loci in the near future. Characterization of etiologic heterogeneity of breast cancer may lead to improvements in the understanding of the biological mechanisms for breast cancer, and ultimately result in improvements in prevention, early detection, and treatment.

Allele-specific up-regulation of FGFR2 increases susceptibility to breast cancer

The recent whole-genome scan for breast cancer has revealed the FGFR2 (fibroblast growth factor receptor 2) gene as a locus associated with a small, but highly significant, increase in the risk of developing breast cancer. Using fine-scale genetic mapping of the region, it has been possible to narrow the causative locus to a haplotype of eight strongly linked single nucleotide polymorphisms (SNPs) spanning a region of 7.5 kilobases (kb) in the second intron of the FGFR2 gene. Here we describe a functional analysis to define the causative SNP, and we propose a model for a disease mechanism. Using gene expression microarray data, we observed a trend of increased FGFR2 expression in the rare homozygotes. This trend was confirmed using real-time (RT) PCR, with the difference between the rare and the common homozygotes yielding a Wilcox p-value of 0.028. To elucidate which SNPs might be responsible for this difference, we examined protein–DNA interactions for the eight most strongly disease-associated SNPs in different breast cell lines. We identify two cis-regulatory SNPs that alter binding affinity for transcription factors Oct-1/Runx2 and C/EBPβ, and we demonstrate that both sites are occupied in vivo. In transient transfection experiments, the two SNPs can synergize giving rise to increased FGFR2 expression. We propose a model in which the Oct-1/Runx2 and C/EBPβ binding sites in the disease-associated allele are able to lead to an increase in FGFR2 gene expression, thereby increasing the propensity for tumour formation.

Recently, a number of whole-genome association studies have identified genes that predispose individuals to common diseases such as cancer. The challenge now is to understand how the identified risk loci contribute to disease, since the majority of these loci are located within introns (which are discarded after transcription) and intergenic regions, and therefore do not change the coding region of nearby genes. This manuscript describes how two single–base pair changes in intron 2 of the FGFR2 (fibroblast growth factor receptor 2) gene, “the top hit” of the breast cancer susceptibility study, exert their function. We find that the changes alter the binding of two transcription factors and cause an increase in FGFR2 gene expression, thus providing a molecular explanation for the risk phenotype. This is the first functional study, to our knowledge, of the risk loci identified for breast cancer in a whole-genome scan and demonstrates that these studies can be used as valid starting points for studying the underlying biology of cancer.

Recent whole-genome scans have identified novel risk genes for many common diseases, challenging researchers to determine how these genes contribute to disease. A new study provides molecular insights into a breast cancer risk factor.

Silencing of keratinocyte growth factor receptor restores 5-fluorouracil and tamoxifen efficacy on responsive cancer cells

Background

Keratinocyte growth factor receptor (KGFR) is a splice variant of the FGFR2 gene expressed in epithelial cells. Activation of KGFR is a key factor in the regulation of physiological processes in epithelial cells such as proliferation, differentiation and wound healing. Alterations of KGFR signaling have been linked to the pathogenesis of different epithelial tumors. It has been also hypothesized that its specific ligand, KGF, might contribute to the development of resistance to 5-fluorouracil (5-FU) in epithelial cancers and tamoxifen in estrogen-positive breast cancers.

Methodology/Principal Findings

Small interfering RNA was transfected into a human keratinocyte cell line (HaCaT), a breast cancer derived cell line (MCF-7) and a keratinocyte primary culture (KCs) to induce selective downregulation of KGFR expression. A strong and highly specific reduction of KGFR expression was observed at both RNA (reduction = 75.7%, P = 0.009) and protein level. KGFR silenced cells showed a reduced responsiveness to KGF treatment as assessed by measuring proliferation rate (14.2% versus 39.0% of the control cells, P<0.001) and cell migration (24.6% versus 96.4% of the control cells, P = 0.009). In mock-transfected MCF-7 cells, KGF counteracts the capacity of 5-FU to inhibit cell proliferation, whereas in KGFR silenced cells KGF weakly interferes with 5-FU antiproliferative effect (11.2% versus 28.4% of the control cells, P = 0.002). The capacity of 5-FU to induce cell death is abrogated by co-treatment with KGF, whereas in KGFR silenced cells 5-FU efficiently induces cell death even combined to KGF, as determined by evaluating cell viability. Similarly, the capacity of tamoxifen to inhibit MCF-7 and KCs proliferation is highly reduced by KGF treatment and is completely restored in KGFR silenced cells (12.3% versus 45.5% of the control cells, P<0.001).

Conclusions/Significance

These findings suggest that selective inhibition of the KGF/KGFR pathway may provide a useful tool to ameliorate the efficacy of the therapeutic strategies for certain epithelial tumors.

Innate Immunity in the Female Reproductive Tract: Role of Sex Hormones in Regulating Uterine Epithelial Cell Protection Against Pathogens

The mucosal immune system in the upper female reproductive tract is uniquely prepared to maintain a balance between the presence of commensal bacteria, sexually transmitted bacterial and viral pathogens, allogeneic spermatozoa, and an immunologically distinct fetus. At the center of this dynamic system are the epithelial cells that line the Fallopian tubes, uterus, cervix and vagina. Epithelial cells provide a first line of defense that confers continuous protection, by providing a physical barrier as well as secretions containing bactericidal and virucidal agents. In addition to maintaining a state of ongoing protection, these cells have evolved to respond to pathogens, in part through Toll-like receptors (TLRs), to enhance innate immune protection and, when necessary, to contribute to the initiation of an adaptive immune response. Against this backdrop, epithelial cell innate and adaptive immune function is modulated to meet the constraints of procreation. The overall goal of this review is to focus on the dynamic role of epithelial cells in the upper reproductive tract, with special emphasis on the uterus, to define the unique properties of these cells as they maintain homeostasis in preparation for successful fertilization and pregnancy while at the same time confer protection against sexually transmitted infections, which threaten to compromise women's reproductive health and survival. By understanding the nature of this protection and the ways in which innate and adaptive immunity are regulated by sex hormones, these studies provide the opportunity to contribute to the foundation of information essential for ensuring reproductive health.

Heterogeneity of breast cancer associations with five susceptibility loci by clinical and pathological characteristics

A three-stage genome-wide association study recently identified single nucleotide polymorphisms (SNPs) in five loci (fibroblast growth receptor 2 (FGFR2), trinucleotide repeat containing 9 (TNRC9), mitogen-activated protein kinase 3 K1 (MAP3K1), 8q24, and lymphocyte-specific protein 1 (LSP1)) associated with breast cancer risk. We investigated whether the associations between these SNPs and breast cancer risk varied by clinically important tumor characteristics in up to 23,039 invasive breast cancer cases and 26,273 controls from 20 studies. We also evaluated their influence on overall survival in 13,527 cases from 13 studies. All participants were of European or Asian origin. rs2981582 in FGFR2 was more strongly related to ER-positive (per-allele OR (95%CI) = 1.31 (1.27-1.36)) than ER-negative (1.08 (1.03-1.14)) disease (P for heterogeneity = 10(-13)). This SNP was also more strongly related to PR-positive, low grade and node positive tumors (P = 10(-5), 10(-8), 0.013, respectively). The association for rs13281615 in 8q24 was stronger for ER-positive, PR-positive, and low grade tumors (P = 0.001, 0.011 and 10(-4), respectively). The differences in the associations between SNPs in FGFR2 and 8q24 and risk by ER and grade remained significant after permutation adjustment for multiple comparisons and after adjustment for other tumor characteristics. Three SNPs (rs2981582, rs3803662, and rs889312) showed weak but significant associations with ER-negative disease, the strongest association being for rs3803662 in TNRC9 (1.14 (1.09-1.21)). rs13281615 in 8q24 was associated with an improvement in survival after diagnosis (per-allele HR = 0.90 (0.83-0.97). The association was attenuated and non-significant after adjusting for known prognostic factors. Our findings show that common genetic variants influence the pathological subtype of breast cancer and provide further support for the hypothesis that ER-positive and ER-negative disease are biologically distinct. Understanding the etiologic heterogeneity of breast cancer may ultimately result in improvements in prevention, early detection, and treatment.

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.

Keratinocyte growth factor expression and activity in cancer: implications for use in patients with solid tumors

Keratinocyte growth factor (KGF) is a locally acting epithelial mitogen that is produced by cells of mesenchymal origin and has an important role in protecting and repairing epithelial tissues. Use of recombinant human KGF (palifermin) in patients with hematologic malignancies reduces the incidence and duration of severe oral mucositis experienced after intensive chemoradiotherapy. These results suggest that KGF may be useful in the treatment of patients with other kinds of tumors, including those of epithelial origin. However, its application in this context raises issues that were not pertinent to its use in hematologic cancer because epithelial tumor cells, unlike blood cells, often express the KGF receptor (FGFR2b). Thus, it is important to examine whether KGF could promote the growth of epithelial tumors or protect such tumor cells from the effects of chemotherapy agents. Analyses of KGF and FGFR2b expression in tumor specimens and of KGF activity on transformed cells in vitro and in vivo do not indicate a definitive role for KGF in tumorigenesis. On the contrary, restoring FGFR2b expression to certain malignant cells can induce cell differentiation or apoptosis. However, other observations suggest that, in specific situations, KGF may contribute to epithelial tumorigenesis. Thus, further studies are warranted to examine the nature and extent of KGF involvement in these settings. In addition, clinical trials in patients with solid tumors are underway to assess the potential benefits of using KGF to protect normal tissue from the adverse effects of chemoradiotherapy and its possible impact on clinical outcome.

FGF9 promotes survival of germ cells in the fetal testis

In addition to its role in somatic cell development in the testis, our data have revealed a role for Fgf9 in XY germ cell survival. In Fgf9-null mice, germ cells in the XY gonad decline in numbers after 11.5 days post coitum (dpc), while germ cell numbers in XX gonads are unaffected. We present evidence that germ cells resident in the XY gonad become dependent on FGF9 signaling between 10.5 dpc and 11.5 dpc, and that FGF9 directly promotes XY gonocyte survival after 11.5 dpc, independently from Sertoli cell differentiation. Furthermore, XY Fgf9-null gonads undergo true male-to-female sex reversal as they initiate but fail to maintain the male pathway and subsequently express markers of ovarian differentiation(Fst and Bmp2). By 14.5 dpc, these gonads contain germ cells that enter meiosis synchronously with ovarian gonocytes. FGF9 is necessary for 11.5 dpc XY gonocyte survival and is the earliest reported factor with a sex-specific role in regulating germ cell survival.

Oral contraceptives and the risk of breast cancer

BACKGROUND

It is uncertain whether the use of an oral contraceptive increases the risk of breast cancer later in life, when the incidence of breast cancer is increased. We conducted a population-based, case-control study to determine the risk of breast cancer among former and current users of oral contraceptives.

METHODS

We interviewed women who were 35 to 64 years old. A total of 4575 women with breast cancer and 4682 controls were interviewed. Conditional logistic regression was used to calculate odds ratios as estimates of the relative risk (incidence-density ratios) of breast cancer.

RESULTS

The relative risk was 1.0 (95 percent confidence interval, 0.8 to 1.3) for women who were currently using oral contraceptives and 0.9 (95 percent confidence interval, 0.8 to 1.0) for those who had previously used them. The relative risk did not increase consistently with longer periods of use or with higher doses of estrogen. The results were similar among white and black women. Use of oral contraceptives by women with a family history of breast cancer was not associated with an increased risk of breast cancer, nor was the initiation of oral-contraceptive use at a young age.

CONCLUSIONS

Among women from 35 to 64 years of age, current or former oral-contraceptive use was not associated with a significantly increased risk of breast cancer.