Cyclooxygenase-2 enhances alpha2beta1 integrin expression and cell migration via EP1 dependent signaling pathway in human chondrosarcoma cells

FGF2 drives osteosarcoma metastasis through activating FGFR1-4 receptor pathway-mediated ICAM-1 expression

Osteosarcoma is a malignant tumor with high metastatic potential, such that the overall 5-year survival rate of patients with metastatic osteosarcoma is only 20%. Therefore, it is necessary to unravel the mechanisms of osteosarcoma metastasis to identify predictors of metastasis by which to develop new therapies. Fibroblast growth factor 2 (FGF2) is a growth factor involved in embryonic development, cell migration, and proliferation. The overexpression of FGF2 and FGF receptors (FGFRs) has been shown to enhance cancer cell proliferation in lung, breast, gastric, and prostate cancers as well as melanoma. Nonetheless, the roles of FGF2 and FGFRs in human osteosarcoma cells remain unknown. In the present study, we found that FGF2 was overexpressed in human osteosarcoma sections and correlated with lung metastasis. Treatment of FGF2 induced migration activity, invasion activity, and intercellular adhesion molecule (ICAM)-1 expression in osteosarcoma cells. In particular, the downregulation or antagonism of FGFR1-4 suppressed FGF2-induced ICAM-1 expression and cancer cell migration. Furthermore, FGFR1, FGFR2, FGFR3, and FGFR4 were involved in FGF2-induced the phospholipase Cβ/protein kinase Cα/proto-oncogene c-Src signaling pathway and triggered c-Jun nuclear translocation. Subsequent c-Jun upregulation of activator protein-1 transcription activity on the ICAM-1 promoter led to an increased migration of osteosarcoma cells. Moreover, the knockdown of endogenous FGF2 suppressed ICAM-1 expression and migration of osteosarcoma cells. These findings suggest that FGF2/FGFR1-4 signaling promotes metastasis via its direct downstream target gene ICAM-1, revealing a novel potential therapeutic target for osteosarcoma.

Combined Ibuprofen-Nanoconjugate Micelles with E-Selectin for Effective Sunitinib Anticancer Therapy

Introduction

Sunitinib, a first-line therapy with a certain effect, was utilized in the early stages of renal cell carcinoma treatment. However, its clinical toxicity, side effects, and its limited bioavailability, resulted in inadequate clinical therapeutic efficacy. Building neoteric, simple, and safe drug delivery systems with existing drugs offers new options. Therefore, we aimed to construct a micelle to improve the clinical efficacy of sunitinib by reusing ibuprofen.

Methods

We synthesized the sialic acid-poly (ethylene glycol)-ibuprofen (SA-PEG-IBU) amphipathic conjugate in two-step reaction. The SA-PEG-IBU amphiphilic conjugates can form into stable SPI nanomicelles in aqueous solution, which can be further loaded sunitinib (SU) to obtain the SPI/SU system. Following nanomicelle creation, sialic acid exposed to the nanomicelle surface can recognize the overexpressed E-selectin receptor on the membrane of cancer cells to enhance cellular uptake. The properties of morphology, stability, and drug release about the SPI/SU nanomicelles were investigated. Confocal microscopy and flow cytometry were used to assess the cellular uptake efficiency of nanomicelles in vitro. Finally, a xenograft tumor model in nude mice was constructed to investigate the body distribution and tumor suppression of SPI/SU in vivo.

Results

The result showed that SPI nanomicelles exhibited excellent tumor targeting performance and inhibited the migration and invasion of tumor cell in vitro. The SPI nanomicelles can improve the accumulation of drugs in the tumor site that showed effective tumor inhibition in vivo. In addition, H&E staining and immunohistochemical analysis demonstrated that the SPI/SU nanomicelles had a superior therapeutic effect and lower biotoxicity.

Conclusion

The SPI/SU nanomicelles displayed excellent anti-tumor ability, and can suppress the metastasis of tumor cell by decreasing the expression of Cyclooxygenase-2 due to the ibuprofen, providing an optimistic clinical application potential by developing a simple but safe drug delivery system.

EP3 enhances adhesion and cytotoxicity of NK cells toward hepatic stellate cells in a murine liver fibrosis model

Natural killer (NK) cells exhibit antifibrotic properties in liver fibrosis (LF) by suppressing activated hepatic stellate cell (HSC) populations. Prostaglandin E2 (PGE2) plays a dual role in innate and adaptive immunity. Here, we found that E-prostanoid 3 receptor (EP3) was markedly downregulated in NK cells from liver fibrosis mice and patients with liver cirrhosis. NK cell-specific deletion of EP3 aggravated hepatic fibrogenesis in mouse models of LF. Loss of EP3 selectively reduced the cytotoxicity of the CD27+CD11b+ double positive (DP) NK subset against activated HSCs. Mechanistically, deletion of EP3 impaired the adhesion and cytotoxicity of DP NK cells toward HSCs through modulation of Itga4-VCAM1 binding. EP3 upregulated Itga4 expression in NK cells through promoting Spic nuclear translocation via PKC-mediated phosphorylation of Spic at T191. Activation of EP3 by sulprostone alleviated CCL4-induced liver fibrosis in mice. Thus, EP3 is required for adhesion and cytotoxicity of NK cells toward HSCs and may serve as a therapeutic target for the management of LF.

Inhibition of PKC/MEK pathway suppresses β1-integrin and mitigates breast cancer cells proliferation

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PGE2 enhanced β1- integrin expression via EP1 receptor, PKC, MEK and NfҡB.

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FOXC2, E2F1 and survivin play a role in PGE2 mediated effect in MCF7 cells.

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PGE2 enhances breast cancer cell cycle through E2F1, FOXC2, survivin and β integrin.

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Biochemical mediators of PKC/MEK pathway could be considered as targets for breast cancer treatment.

Prostaglandin E2 (PGE2) and β1-integrin have been correlated with breast cancer, where both could enhance progression and metastasis. Protein kinase C (PKC) and MEK have played a vital role in breast cancer development. Our study was conducted to elucidate the effect of inhibition of E-prostanoid receptor 1 (EP1)/ PKC/ MEK/ β1-integrin pathway in mitigating breast cancer progression and to evaluate the role of the intermediate signals FOXC2, E2F1, NF-ҡB and survivin. MCF7 cells were treated with 17 -PT-PGE2, an EP1 agonist, for 24 h, and β1-integrin was measured. To MCF7 cells treated with 17-PT-PGE2, inhibitors of either EP1, MEK, PKC or NF-ҡB were added followed by measurement of β1-integrin gene expression and cell proliferation in each case. Addition of 17- PT-PGE2 to MCF7 cells showed enhancement of both cell proliferation, and cell cycle transition from G1 to S phase. In addition, activation of EP1 receptor increased β1-integrin expression. On the contrary, inhibition of EP1 receptor showed a decrease in the cell proliferation, β1-integrin expression and cells transition to S phase, but increased cell count in apoptotic phase. Selective inhibition of each of MEK, PKC, and NF-ҡB suppressed 17 -PT-PGE2-mediated β1-integrin expression as well as cell proliferation. Furthermore, FOXC2, phosphorylated NF-ҡB, E2F1, and survivin levels were upregulated with 17- PT-PGE2 and suppressed by MEK, PKC and NF-ҡB inhibitors. Targeting the biochemical mediators of PKC/MEK pathway may be of value in developing new chemical entities for cancer treatment.

Expression of Amphiregulin in Enchondromas and Central Chondrosarcomas

OBJECTIVES

The aim of this study was to evaluate the role of amphiregulin protein, an epidermal growth factor receptor ligand, in cartilaginous tumors.

METHODS

Amphiregulin expression was examined in 31 enchondromas and 67 chondrosarcomas using immunohistochemistry analysis.

RESULTS

Overall, 15 enchondromas (48.40%) and 24 chondrosarcomas (35.82%) were positive for amphiregulin. According to the receiver operating characteristic curve test, no difference in amphiregulin expression was observed between enchondromas and low-grade chondrosarcomas (p=0.0880). Additionally, 39 lesions (16 in short bones, 13 in long bones, and 10 in flat bones) were positive for amphiregulin, exhibiting a higher percentage of positive cells (p=0.0030) and intensity of immunohistochemical expression (p=0.0055) in short bone lesions than in others. Among 25 enchondromas localized in short bones, 15 expressed amphiregulin; however, all 6 cases localized in long bones were negative for this marker (p=0.0177).

CONCLUSIONS

Amphiregulin did not help in distinguishing enchondromas from low-grade chondrosarcomas. The present study is the first to document the expression of this immunohistochemical marker in enchondromas. Furthermore, amphiregulin expression in enchondromas was localized in short bones, indicating a phenotypic distinction from that in long bones. This distinction may contribute to an improved understanding of the pathogenesis of these lesions.

CXCL13/CXCR5 Interaction Facilitates VCAM-1-Dependent Migration in Human Osteosarcoma

Osteosarcoma is the most common primary tumor of the skeletal system and is well-known to have an aggressive clinical outcome and high metastatic potential. The chemokine (C-X-C motif) ligand 13 (CXCL13) plays a vital role in the development of several cancers. However, the effect of CXCL13 in the motility of osteosarcoma cells remains uncertain. Here, we found that CXCL13 increases the migration and invasion potential of three osteosarcoma cell lines. In addition, CXCL13 expression was upregulated in migration-prone MG-63 cells. Vascular cell adhesion molecule 1 (VCAM-1) siRNA and antibody demonstrated that CXCL13 promotes migration via increasing VCAM-1 production. We also show that CXCR5 receptor controls CXCL13-mediated VCAM-1 expression and cell migration. Our study identified that CXCL13/CXCR5 axis facilitate VCAM-1 production and cell migration in human osteosarcoma via the phospholipase C beta (PLCβ), protein kinase C α (PKCα), c-Src, and nuclear factor-κB (NF-κB) signaling pathways. CXCL13 and CXCR5 appear to be a novel therapeutic target in metastatic osteosarcoma.

MRI and MRS of intact perfused cancer cell metabolism, invasion, and stromal cell interactions

Because of the spatial and temporal heterogeneities of cancers, technologies to investigate cancer cells and the consequences of their interactions with abnormal physiological environments, such as hypoxia and acidic extracellular pH, with stromal cells, and with the extracellular matrix, under controlled conditions, are valuable to gain insights into the functioning of cancers. These insights can lead to an understanding of why cancers invade and metastasize, and identify effective treatment strategies. Here we have provided an overview of the applications of MRI/MRS/MRSI to investigate intact perfused cancer cells, their metabolism and invasion, and their interactions with stromal cells and the extracellular matrix.

Chondrosarcoma: An overview of clinical behavior, molecular mechanisms mediated drug resistance and potential therapeutic targets

Sarcomas are known as a heterogeneous class of cancers arisen in the connective tissues and demonstrated various histological subtypes including both soft tissue and bone origin. Chondrosarcoma is one of the main types of bone sarcoma that shows a considerable deficiency in response to chemotherapy and radiotherapy. While conventional treatment based on surgery, chemo-and radiotherapy are used in this tumor, high rate of death especially among children and adolescents are reported. Due to high resistance to current conventional therapies in chondrosarcoma, there is an urgent requirement to recognize factors causing resistance and discover new strategies for optimal treatment. In the past decade, dysregulation of genes associated with tumor development and therapy resistance has been studied to find potential therapeutic targets to overcome resistance. In this review, clinical aspects of chondrosarcoma are summarized. Moreover, it gives a summary of gene dysregulation, mutation, histone modifications and non-coding RNAs associated with tumor development and therapeutic response modulation. Finally, the probable role of tumor microenvironment in chondrosarcoma drug resistance and targeted therapies as a promising molecular therapeutic approach are summarized.

Correlations of IGF-1R and COX-2 Expressions with Ras and BRAF Genetic Mutations, Clinicopathological Features and Prognosis of Colorectal Cancer Patients

This case-control study aims to investigate the correlations of insulin-like growth factor receptor 1 (IGF-1R) and cyclooxygenase 2 (COX-2) expressions with Ras and BRAF genetic mutations, clinicopathological features and prognosis of colorectal cancer (CRC) patients. A total of 213 CRC patients (case group) and 200 healthy individuals (control group) were selected from our hospital. Ras (K-Ras/N-Ras) and BRAF genetic mutations were detected by direct sequencing. The positive expression rates of IGF-IR and COX-2 in CRC and normal tissues were detected using immunohistochemistry. RT-qPCR and Western blotting were applied to detect the mRNA and protein expressions of IGF-IR and COX-2 in CRC tissues and normal tissues. Total mutation rate of N-Ras, BRAF and K-Ras in case group were 5.2%, 12.2% and 47.4%, respectively. The expressions of IGF-IR and COX-2 were higher in CRC tissues with Ras and BRAF mutations than in those without. CRC tissues with Ras mutation showed higher COX-2 expression than those with BRAF mutation. IGF-IR and COX-2 expressions were correlated to infiltration degree, lymphatic metastasis (in CRC tissues with and without Ras and BRAF mutations), and Dukes stages (only in CRC tissues with Ras and BRAF mutations). CRC patients with negative expressions of IGF-IR and COX-2 had significantly higher accumulative survival rate and longer mean survival duration than those with positive expressions of IGF-IR and COX-2. These findings indicate that IGF-1R and COX-2 expressions may be associated with Ras and BRAF genetic mutations, clinicopathological feature and prognosis of CRC patients.

Cyclooxygenase-2 induced β1-integrin expression in NSCLC and promoted cell invasion via the EP1/MAPK/E2F-1/FoxC2 signal pathway

Cyclooxygenase-2 (COX-2) has been implicated in cell invasion in non-small-cell lung cancer (NSCLC). However, the mechanism is unclear. The present study investigated the effect of COX-2 on β1-integrin expression and cell invasion in NSCLC. COX-2 and β1-integrin were co-expressed in NSCLC tissues. COX-2 overexpression or Prostaglandin E2 (PGE2) treatment increased β1-integrin expression in NSCLC cell lines. β1-integrin silencing suppressed COX-2-mediated tumour growth and cancer cell invasion in vivo and in vitro. Prostaglandin E Receptor EP1 transfection or treatment with EP1 agonist mimicked the effect of PGE₂ treatment. EP1 siRNA blocked PGE₂-mediated β1-integrin expression. EP1 agonist treatment promoted Erk1/2, p38 phosphorylation and E2F-1 expression. MEK1/2 and p38 inhibitors suppressed EP1-mediated β1-integrin expression. E2F-1 silencing suppressed EP1-mediated FoxC2 and β1-integrin upregulation. ChIP and Luciferase Reporter assays identified that EP1 agonist treatment induced E2F-1 binding to FoxC2 promotor directly and improved FoxC2 transcription. FoxC2 siRNA suppressed β1-integrin expression and EP1-mediated cell invasion. Immunohistochemistry showed E2F-1, FoxC2, and EP1R were all highly expressed in the NSCLC cases. This study suggested that COX-2 upregulates β1-integrin expression and cell invasion in NSCLC by activating the MAPK/E2F-1 signalling pathway. Targeting the COX-2/EP1/PKC/MAPK/E2F-1/FoxC2/β1-integrin pathway might represent a new therapeutic strategy for the prevention and treatment of this cancer.

Amphiregulin enhances intercellular adhesion molecule-1 expression and promotes tumor metastasis in human osteosarcoma

Osteosarcoma is a common, high malignant, and metastatic bone cancer. Amphiregulin (AREG) has been associated with cancer cellular activities. However, the effect of AREG on metastasis activity in human osteosarcoma cells has yet to be determined. We determined that AREG increases the expression of intercellular adhesion molecule-1 (ICAM-1) through PI3K/Akt signaling pathway via its interaction with the epidermal growth factor receptor, thus resulting in the enhanced cell migration of osteosarcoma. Furthermore, AREG stimulation increased the association of NF-κB to ICAM-1 promoter which then up-regulated ICAM-1 expression. Finally, we observed that shRNA silencing of AREG decreased osteosarcoma metastasis in vivo. Our findings revealed a relationship between osteosarcoma metastatic potential and AREG expression and the modulating effect of AREG on ICAM-1 expression.

The PIM1 kinase promotes prostate cancer cell migration and adhesion via multiple signalling pathways

The ability of cells to migrate and form metastases is one of the fatal hallmarks of cancer that can be conquered only with better understanding of the molecules and regulatory mechanisms involved. The oncogenic PIM kinases have been shown to support cancer cell survival and motility, but the PIM-regulated pathways stimulating cell migration and invasion are less well characterized than those affecting cell survival. Here we have identified the glycogen synthase kinase 3β (GSK3B) and the forkhead box P3 (FOXP3) transcription factor as direct PIM targets, whose tumour-suppressive effects in prostate cancer cells are inhibited by PIM-induced phosphorylation, resulting in increased cell migration. Targeting GSK3B is also essential for the observed PIM-enhanced expression of the prostaglandin-endoperoxide synthase 2 (PTGS2), which is an important regulator of both cell migration and adhesion. Accordingly, selective inhibition of PIM activity not only reduces cell migration, but also affects integrin-mediated cell adhesion. Taken together, these data provide novel mechanistic insights on how and why patients with metastatic prostate cancer may benefit from therapies targeting PIM kinases, and how such approaches may also be applicable to inflammatory conditions.

Amphiregulin enhances alpha6beta1 integrin expression and cell motility in human chondrosarcoma cells through Ras/Raf/MEK/ERK/AP-1 pathway

Chondrosarcoma is a malignant tumor that produces cartilage matrix. The most lethal aspect is its metastatic property. We demonstrated that amphiregulin (AR) is significantly upregulated in highly aggressive cells. AR silencing markedly suppressed cell migration. Exogenous AR markedly increased cell migration by transactivation of α6β1 integrin expression. A neutralizing α6β1 integrin antibody can abolish AR-induced cell motility. Knockdown of AR inhibits metastasis of cells to the lung in vivo. Furthermore, elevated AR expression is positively correlated with α6β1 integrin levels and higher grades in patients. These findings can potentially serve as biomarker and therapeutic approach for controlling chondrosarcoma metastasis.

COX-2 dependent regulation of mechanotransduction in human breast cancer cells

The ability of living cells to exert physical forces upon their surrounding is a necessary prerequisite for diverse biological processes, such as local cellular migrations in wound healing to metastatic-invasion of cancer. How forces are coopted in metastasis has remained unclear, however, because the mechanical interplay between cancer cells and the various stromal components has not been experimentally accessible. Current dogma implicates inflammation in these mechanical processes. Using Fourier transform traction microscopy, we measured the force-generating capacity of human breast cancer cells occupying a spectrum of invasiveness as well as basal and inducible COX-2 expression (MCF-7<SUM-149<MDA-MB-231). Compared with non-invasive MCF-7 and moderately-invasive SUM-149, poorly-differentiated MDA-MB-231 cells showed increased cellular dispersion on collagen matrix that was accompanied by emergent distribution of contractile stresses at the interface between the adherent cell and its substrate, defined herein as the traction field. In metastatic MDA-MB-231 cells, the local tractions were precisely tuned to the surrounding matrix rigidity in a physiologic range with the concomitant expression of mechanosensitive integrin β1. These discrete responses at the single-cell resolution were correlated with PGE2 secretion and were ablated by shRNA-mediated knockdown of COX-2. Both COX-2-silenced and COX-2-expressing cells expressed EP2 and EP4 receptors, but not EP1 and EP3. Exogenous addition of PGE2 increased cell tractions and stiffened the underlying cytoskeletal network. To our knowledge this is the first report linking the expression of COX-2 with mechanotransduction of human breast cancer cells, and the regulation of COX-2-PGE2-EP signaling with physical properties of the tumor microenvironment. Drug treatments aimed at reducing this mechanical interplay may have therapeutic potential in the treatment of breast cancer.

Epigenetic silencing of ITGA2 by MiR-373 promotes cell migration in breast cancer

The loss of ITGA2 plays an important role in cancer metastasis in several solid cancers. However, the molecular mechanism of ITGA2 loss in primary cancers remains unclear. In this study, we found that a lower ITGA2 protein level was observed in breast cancers compared to adjacent non-cancerous breast tissues. Interestingly, the reduction degree of ITGA2 at the protein level was far more than that at the mRNA level. We further showed that the translation of ITGA2 mRNA was directly inhibited by miR-373 through binding to ITGA2-3’UTR. Silencing of ITGA2 detached cell-cell interactions, induced the deploymerization of stress fiber F-actin and stimulated cancer cell migration, similar to the effect of miR-373 over-expression. The co-expression of ITGA2, not ITGA2-3’UTR, could abrogate miR-373-induced cancer cell migration because that the expression of ITGA2-3’UTR was inhibited by co-transfected miR-373. ITGA2 protein level was inversely associated with miR-373 level in breast cancers (r = -0.663, P<0.001). 73.33% of breast cancer patients with high miR-373 and low ITGA2 expression exhibited the lymph node-positive metastases. Together, our results show that epigenetic silencing of ITGA2 by miR-373 stimulates breast cancer migration, and miR-373^high/ITGA2^low may be as a prognosis biomarker for breast cancer patients.

Nephroblastoma overexpressed gene (NOV) enhances RCC cell motility through upregulation of ICAM-1 and COX-2 expression via Akt pathway

Renal cell carcinoma (RCC) carries a high risk of malignancy and metastasis. The inducible isoform of prostaglandin synthase, cyclooxygenase (COX)-2, and ICAM-1 may be involved in tumor metastasis. CCN3, also called nephroblastoma overexpressed gene (NOV), has been found to regulate the proliferation and differentiation of cancer cells. The effects of NOV on RCC cell migration and expression of COX-2 and ICAM-1 have not described yet in detail. But here, NOV was found to promote the migration and expression of COX-2 and ICAM-1 in human RCC cells. Akt inhibitor was found to interfere with this NOV-induced migration and up-regulation of COX-2 and ICAM-1 in RCC cells. NOV stimulation was here found to promote the phosphorylation of Akt. RCC tissue chips were subjected to IHC staining, which showed COX-2 expression in RCC tissues to be a significantly closely correlated with NOV expression, with significance determined using Pearson correlation testing (P < 0.05). The results of the current work indicate that NOV activates COX-2 and ICAM-1 through Akt, promoting the migration of RCC cells.

Prostaglandin E2 stimulates β1-integrin expression in hepatocellular carcinoma through the EP1 receptor/PKC/NF-κB pathway

Prostaglandin E₂ (PGE₂) has been implicated in cell invasion in hepatocellular carcinoma (HCC), via increased β1-integrin expression and cell migration; however, the mechanism remains unclear. PGE₂ exerts its effects via four subtypes of the E prostanoid receptor (EP receptor 1–4). The present study investigated the effect of EP1 receptor activation on β1-integrin expression and cell migration in HCC. Cell migration increased by 60% in cells treated with 17-PT-PGE₂ (EP1 agonist), which was suppressed by pretreatment with a β1-integrin polyclonal antibody. PGE₂ increased β1-integrin expression by approximately 2-fold. EP1 receptor transfection or treatment with 17-PT-PGE₂ mimicked the effect of PGE₂ treatment. EP1 siRNA blocked PGE₂-mediated β1-integrin expression. 17-PT-PGE₂ treatment induced PKC and NF-κB activation; PKC and NF-κB inhibitors suppressed 17-PT-PGE₂-mediated β1-integrin expression. FoxC2, a β1-integrin transcription factor, was also upregulated by 17-PT-PGE₂. NF-κB inhibitor suppressed 17-PT-PGE₂-mediated FoxC2 upregulation. Immunohistochemistry showed p65, FoxC2, EP1 receptor and β1-integrin were all highly expressed in the HCC cases. This study suggested that PGE₂ upregulates β1-integrin expression and cell migration in HCC cells by activating the PKC/NF-κB signaling pathway. Targeting PGE₂/EP1/PKC/NF-κB/FoxC2/β1-integrin pathway may represent a new therapeutic strategy for the prevention and treatment of this cancer.

Paeonol suppresses chondrosarcoma metastasis through up-regulation of miR-141 by modulating PKCδ and c-Src signaling pathway

Chondrosarcoma, a primary malignant bone cancer, has potential for local invasion and distant metastasis, especially to the lungs. Patients diagnosed with it show poor prognosis. Paeonol (2'-hydroxy-4'-methoxyacetophenone), the main active compound of traditional Chinese remedy Paeonia lactiflora Pallas, exhibits anti-inflammatory and anti-tumor activity; whether paeonol regulates metastatic chondrosarcoma is largely unknown. Here, we find paeonol do not increase apoptosis. By contrast, at non-cytotoxic concentrations, paeonol suppresses migration and invasion of chondrosarcoma cells. We also demonstrate paeonol enhancing miR-141 expression and miR-141 inhibitor reversing paeonol-inhibited cell motility; paeonol also reduces protein kinase C (PKC)d and c-Src kinase activity. Since paeonol inhibits migration and invasion of human chondrosarcoma via up-regulation of miR-141 via PKCd and c-Src pathways, it thus might be a novel anti-metastasis agent for treatment of metastatic chondrosarcoma.

PGE2 signaling and its biosynthesis-related enzymes in cholangiocarcinoma progression

Prostaglandin E2 (PGE2) involves in progression of various chronic inflammation-related cancers including cholangiocarcinoma (CCA). This study aimed to determine the role of PGE2 signaling, its biosynthesis-related enzymes in a clinical prognosis, and their targeted inhibition in CCA progression. The immunohistochemical staining of cyclooxygenase (COX)-1, COX-2, mPGES-1, EP1, and EP4 was examined in CCA tissues, and their expressions were compared with clinicopathological parameters. The effect of PGE2 on levels of its signaling molecules was examined in CCA cell lines using proteome profiler array. The suppression of mPGES-1 using a small-molecule inhibitor (CAY10526) and small interfering RNA (siRNA) was determined for growth and migration ability in CCA cells. The results indicated that strong expressions of COX-1, COX-2, mPGES-1, EP1, and EP4 were found in CCA tissues as 87.5, 47.5, 52.5, 55, and 80 % of frequencies, respectively. High mPGES-1 expression was significantly correlated with tumor stages III-IV (p = 0.001), lymph node metastasis (p = 0.004), shorter survival (p = 0.009), and prognostic indicator of CCA patients (HR = 2.512, p = 0.041). Expressions of COX-1, COX-2, and EP receptors did not correlate with data tested from patients. PGE2 markedly enhanced protein levels of integrinα6, VE-cadherin, Jagged1, and Notch3, and CAY10526 suppressed those protein levels as well as PGE2 production in CCA cells. CAY10526 and siRNA mPGES-1 markedly suppressed mPGES-1 protein levels, growth, and migration abilities of CCA cell lines. In conclusion, PGE2 signaling strongly promotes CCA progression. Therefore, inhibition of PGE2 synthesis by suppression of its biosynthesis-related enzymes could be useful for prevention and treatment of CCA.

Transforming growth factor alpha promotes osteosarcoma metastasis by ICAM-1 and PI3K/Akt signaling pathway

Osteosarcoma is the most common primary malignancy of bone and is characterized by a high malignant and metastatic potential. Transforming growth factor alpha (TGF-α) is classified as the EGF (epidermal growth factor)-like family, which is involved in cancer cellular activities such as proliferation, motility, migration, adhesion and invasion abilities. However, the effect of TGF-α on human osteosarcoma is largely unknown. We found that TGF-α increased the cell migration and expression of intercellular adhesion molecule-1 (ICAM-1) in human osteosarcoma cells. Transfection of cells with ICAM-1 siRNA reduced TGF-α-mediated cell migration. We also found that the phosphatidylinositol 3'-kinase (PI3K)/Akt/NF-κB pathway was activated after TGF-α treatment, and TGF-α-induced expression of ICAM-1 and cell migration was inhibited by the specific inhibitors and siRNAs of PI3K, Akt, and NF-κB cascades. In addition, knockdown of TGF-α expression markedly decreased cell metastasis in vitro and in vivo. Our results indicate that TGF-α/EGFR interaction elicits PI3K and Akt activation, which in turn activates NF-κB, resulting in the expression of ICAM-1 and contributing the migration of human osteosarcoma cells.

Prostaglandin E2 upregulates β1 integrin expression via the E prostanoid 1 receptor/nuclear factor κ-light-chain-enhancer of activated B cells pathway in non-small-cell lung cancer cells

The prostaglandin E2 (PGE2) E prostanoid (EP)1 receptor shown to be associated with lung cancer cell invasion. However, the mechanism of EP1 receptor-mediated cell migration remains to be elucidated. β1 integrin is an essential regulator of the tumorigenic properties of non-small-cell lung carcinoma (NSCLC) cells. To date, little is known regarding the association between the EP1 receptor and β1 integrin expression. The present study investigated the effect of EP1 receptor activation on β1 integrin expression and cell migration in NSCLC cells. A total of 34 patients with clinical diagnosis of NSCLC and 10 patients with benign disease were recruited for the present study. The expression levels of the EP1 receptor and β1 integrin expression were studied in resected lung tissue using immunohistochemistry. A statistical analysis was performed using Stata se12.0 software. The effects of PGE2, EP1 agonist 17-phenyl trinor-PGE2 (17-PT-PGE2) and the nuclear factor κ-B (NF-κB) inhibitor on β1 integrin expression were investigated on A549 cells. The expression of β1 integrin and the phosphorylation of NF-κB‑p65 Ser536 was investigated by western blot analysis. Cell migration was assessed by a transwell assay. The results demonstrated that β1 integrin and EP1 receptor expression exhibited a positive correlation of evident significance in the 44 samples. The in vitro migration assay revealed that cell migration was increased by 30% when the cells were treated with 5 µM 17-PT-PGE2 and that the pre-treatment of β1 integrin monoclonal antibody inhibited 17-PT-PGE2‑mediated cell migration completely. PGE2 and 17-PT-PGE2 treatment increased β1 integrin expression. RNA interference against the EP1 receptor blocked the PGE2-mediated β1 integrin expression in A549 cells. Treatment with 17-PT-PGE2 induced NF-κB activation, and the selective NF-κB inhibitor pyrrolidinedithiocarbamate inhibited 17-PT-PGE2-mediated β1 integrin expression. In conclusion, the present study indicated that the PGE2 EP1 receptor regulates β1 integrin expression and cell migration in NSCLC cells by activating the NF-κB signaling pathway. Targeting the PGE2/EP1/β1 integrin signaling pathway may aid in the development of new therapeutic strategies for the prevention and treatment of this type of cancer.

Prostaglandin E2 promotes hepatocellular carcinoma cell invasion through upregulation of YB-1 protein expression

Prostaglandin E2 (PGE2) has been implicated in hepatocellular carcinoma cell invasion. Recently, it was reported that Y box-binding protein 1 (YB-1) is closely correlated with malignancy. This study was designed to examine the mechanisms by which PGE2 increases YB-1 expression and promotes HCC cell invasion. PGE2 greatly enhanced HCC cell invasion through upregulation of the YB-1 protein, and the EP1 receptor is mainly responsible for this regulation. Src and EGFR were both activated by PGE2, which in turn increased the phosphorylation levels of p44/42 MAPK. Src, EGFR and p44/42 MAPK were all involved in PGE2-induced YB-1 expression. Chemical inhibitors and RNAi analysis all confirmed the role of mTOR complex 1 in YB-1 expression induced by PGE2. Furthermore, YB-1 was able to regulate the expression of a series of EMT-associated genes, which indicated that YB-1 could have the potential to control the epithelial-mesenchymal transition process in HCC cells. These findings reveal that PGE2 upregulated YB-1 expression through the EP1/Src/EGFR/p44/42 MAPK/mTOR pathway, which greatly enhanced HCC cell invasion. This study for the first time describes the mechanisms through which PGE2 regulates YB-1 expression and promotes HCC cell invasion.

Novel strategies for the treatment of chondrosarcomas: targeting integrins

Chondrosarcomas are a heterogeneous group of malignant bone tumors that are characterized by the production of cartilaginous extracellular matrix. They are the second most frequently occurring type of bone malignancy. Surgical resection remains the primary mode of treatment for chondrosarcomas, since conventional chemotherapy and radiotherapy are largely ineffective. Treatment of patients with high-grade chondrosarcomas is particularly challenging, owing to the lack of effective adjuvant therapies. Integrins are cell surface adhesion molecules that regulate a variety of cellular functions. They have been implicated in the initiation, progression, and metastasis of solid tumors. Deregulation of integrin expression and/or signaling has been identified in many chondrosarcomas. Therefore, the development of new drugs that can selectively target regulators of integrin gene expression and ligand-integrin signaling might hold great promise for the treatment of these cancers. In this review, we provide an overview of the current understanding of how growth factors, chemokines/cytokines, and other inflammation-related molecules can control the expression of specific integrins to promote cell migration. We also review the roles of specific subtypes of integrins and their signaling mechanisms, and discuss how these might be involved in tumor growth and metastasis. Finally, novel therapeutic strategies for targeting these molecules will be discussed.

TGF-β1 downregulates COX-2 expression leading to decrease of PGE2 production in human lung cancer A549 cells, which is involved in fibrotic response to TGF-β1

Transforming growth factor-ß1 (TGF-β1) is a multifunctional cytokine that is involved in various pathophysiological processes, including cancer progression and fibrotic disorders. Here, we show that treatment with TGF-β1 (5 ng/mL) induced downregulation of cyclooxygenase-2 (COX-2), leading to reduced synthesis of prostaglandin E2 (PGE2), in human lung cancer A549 cells. Treatment of cells with specific inhibitors of COX-2 or PGE2 receptor resulted in growth inhibition, indicating that the COX-2/PGE2 pathway contributes to proliferation in an autocrine manner. TGF-β1 treatment induced growth inhibition, which was attenuated by exogenous PGE2. TGF-β1 is also a potent inducer of epithelial mesenchymal transition (EMT), a phenotype change in which epithelial cells differentiate into fibroblastoid cells. Supplementation with PGE2 or PGE2 receptor EP4 agonist PGE1-alcohol, as compared with EP1/3 agonist sulprostone, inhibited TGF-β1-induced expression of fibronectin and collagen I (extracellular matrix components). Exogenous PGE2 or PGE2 receptor agonists also suppressed actin remodeling induced by TGF-β1. These results suggest that PGE2 has an anti-fibrotic effect. We conclude that TGF-β1-induced downregulation of COX-2/PGE2 signaling is involved in facilitation of fibrotic EMT response in A549 cells.

Prostaglandin E₂ receptor EP1-mediated phosphorylation of focal adhesion kinase enhances cell adhesion and migration in hepatocellular carcinoma cells

The prostaglandin E₂ (PGE₂) EP1 receptor has been implicated in hepatocellular carcinoma (HCC) cell invasion. However, little is known about the mechanisms of EP1 receptor-mediated cell adhesion and migration. We previously showed that PGE₂ promotes cell adhesion and migration by activating focal adhesion kinase (FAK). The present study was designed to elucidate the association between the EP1 receptor and FAK activation in HCC cells and to investigate the related signaling pathways. The effects of PGE₂, EP1 agonist 17-phenyl trinor-PGE₂ (17-PT-PGE₂), PKC and EGFR inhibitors on FAK activation were investigated by treatment of Huh-7 cells. Phosphorylation of FAK Y397 and c-Src Y416 was investigated by western blotting. Cell adhesion and migration were analyzed by WST and transwell assays, respectively. Protein kinase C (PKC) activity was measured with a PKC assay kit. The results showed that 17-PT-PGE₂ (3 µM) increased FAK Y397 phosphorylation by more than 2-fold and promoted cell adhesion and migration in Huh-7 cells. In transfected 293 cells, expression of the EP1 receptor was confirmed to upregulate FAK phosphorylation, while the EP1 receptor antagonist sc-19220 decreased PGE₂-mediated FAK activation. PKC activity and c-Src Y416 phosphorylation were enhanced after 17-PT-PGE₂ treatment. Both PKC and c-Src inhibitor suppressed the 17-PT-PGE₂-upregulated FAK phosphorylation, as well as 17-PT-PGE₂-induced cell adhesion and migration. In addition, exogenous epidermal growth factor (EGF) treatment increased FAK phosphorylation. The EGF receptor (EGFR) inhibitor also suppressed 17-PT-PGE₂-upregulated FAK phosphorylation. Our study suggests that the PGE₂ EP1 receptor regulates FAK phosphorylation by activating the PKC/c-Src and EGFR signal pathways, which may coordinately regulate adhesion and migration in HCC.

TSC2 modulates cell adhesion and migration via integrin-α1β1

Recent evidence suggests that the rare and progressive lung disease lymphangioleiomyomatosis (LAM) is metastatic in nature. Dysfunction of the tumor suppressor genes tuberous sclerosis complex (TSC), in particular mutational inactivation of TSC2, enhances both cell proliferation and migration. Although substantial progress has been made in understanding the role of TSC2 in abnormal LAM cell proliferation and its pharmacological targeting, the mechanisms underlying the enhanced migratory capacity in LAM are not well understood. In this study, we examined the role of TSC2 in cell attachment, spreading, and migration, processes that contribute to the metastatic phenotype. Here we show that loss of TSC2 increased both the attachment and spreading of mouse embryonic fibroblasts to the extracellular matrix proteins collagen type I and fibronectin and that reexpression of TSC2 reduced these effects. Integrin-α1β1 modulated cell migration with the β1-subunit involved in cell attachment and spreading as shown by using functional blocking antibodies. Loss of TSC2 increased integrin-α1 expression, and inhibition of this integrin subunit reduced cell migration. The enhanced attachment and spreading were independent of the intracellular signaling pathways mammalian target of rapamycin complex 1 and Rho-associated kinase, as pharmacological inhibition with rapamycin or Y27632, respectively, was without effect. Together, these data demonstrate that TSC2 controls cell migration, attachment, and spreading through the α1β1-integrin receptor and thus suggest a potential therapeutic target for the treatment of increased cell invasiveness in LAM.

Prostanoid EP1 receptor as the target of (-)-epigallocatechin-3-gallate in suppressing hepatocellular carcinoma cells in vitro

AIM

To investigate the effects of (-)-epigallocatechin-3-gallate (EGCG), an active compound in green tea, on prostaglandin E(2) (PGE(2))-induced proliferation and migration, and the expression of prostanoid EP(1) receptors in hepatocellular carcinoma (HCC) cells.

METHODS

HCC cell line HepG2, human hepatoma cell lines MHCC-97L, MHCC-97H and human hepatocyte cell line L02 were used. Cell viability was analyzed using MTT assay. PGE(2) production was determined with immunoassay. Wound healing assay and transwell filter assay were employed to assess the extent of HCC cell migration. The expression of EP(1) receptor and Gq protein were examined using Western blot assay.

RESULTS

PGE(2) (4-40000 nmol/L) or the EP(1) receptor agonist ONO-DI-004 (400-4000 nmol/L) increased the viability and migration of HepG2 cells in concentration-dependent manners. EGCG (100 μg/mL) significantly inhibited the viability and migration of HepG2 cells induced by PGE(2) or ONO-DI-004. HepG2 cells secreted an abundant amount of PGE(2) into the medium, and EGCG (100 μg/mL) significantly inhibited the PGE(2)production and EP(1) receptor expression in HepG2 cells. EGCG (100 μg/mL) also inhibited the viability of MHCC-97L cells, but not that of MHCC-97H cells. Both EGCG (100 μg/mL) and EP(1) receptor antagonist ONO-8711 inhibited PGE(2) 4 μmol/L and ONO-DI-004 400 nmol/L-induced growth and migration of HepG2 cells. Both EGCG (100 μg/mL) and ONO-8711 210 nmol/L inhibited PGE(2)- and ONO-DI-004-induced EP(1) expression. EGCG and ONO-8711 had synergistic effects in inhibiting EP(1) receptor expression. PGE(2), ONO-DI-004, ONO-8711, and EGCG had no effects on Gq expression in HepG2 cells, respectively.

CONCLUSION

These findings suggest that the anti-HCC effects of EGCG might be mediated, at least partially, through the suppressing EP(1) receptor expression and PGE(2) production.

Cyclooxygenases and lipoxygenases in cancer

Cancer initiation and progression are multistep events that require cell proliferation, migration, extravasation to the blood or lymphatic vessels, arrest to the metastatic site, and ultimately secondary growth. Tumor cell functions at both primary or secondary sites are controlled by many different factors, including growth factors and their receptors, chemokines, nuclear receptors, cell-cell interactions, cell-matrix interactions, as well as oxygenated metabolites of arachidonic acid. The observation that cyclooxygenases and lipoxygenases and their arachidonic acid-derived eicosanoid products (prostanoids and HETEs) are expressed and produced by tumor cells, together with the finding that these enzymes can regulate cell growth, survival, migration, and invasion, has prompted investigators to analyze the roles of these enzymes in cancer progression. In this review, we focus on the contribution of cyclooxygenase- and lipoxygenase-derived eicosanoids to tumor cell function in vitro and in vivo and discuss hope and tribulations of targeting these enzymes for cancer prevention and treatment.

Basic aspects of tumor cell fatty acid-regulated signaling and transcription factors

This article reviews the current knowledge and experimental research about the mechanisms by which fatty acids and their derivatives control specific gene expression involved during carcinogenesis. Changes in dietary fatty acids, specifically the polyunsaturated fatty acids of the ω-3 and ω-6 families and some derived eicosanoids from lipoxygenases, cyclooxygenases, and cytochrome P-450, seem to control the activity of transcription factor families involved in cancer cell proliferation or cell death. Their regulation may be carried out either through direct binding to DNA as peroxisome proliferator-activated receptors or via modulation in an indirect manner of signaling pathway molecules (e.g., protein kinase C) and other transcription factors (nuclear factor kappa B and sterol regulatory element binding protein). Knowledge of the mechanisms by which fatty acids control specific gene expression may identify important risk factors for cancer and provide insight into the development of new therapeutic strategies for a better management of whole body lipid metabolism.

CCN3 increases cell motility and MMP-13 expression in human chondrosarcoma through integrin-dependent pathway

Chondrosarcoma is a type of highly malignant tumor with a potent capacity to invade locally and cause distant metastasis. Chondrosarcoma shows a predilection for metastasis to the lungs. CCN3, also called nephroblastoma overexpressed gene (NOV), regulates proliferation and differentiation of cancer cells. However, the effect of CCN3 on migration activity in human chondrosarcoma cells is mostly unknown. Here, we found that CCN3 increased the migration and expression of matrix metalloproteinase (MMP)-13 in human chondrosarcoma cells (JJ012 cells). αvβ3 or αvβ5 monoclonal antibody (mAb), phosphatidylinositol 3-kinase (PI3K) inhibitors (Ly294002 and wortmannin) and Akt inhibitor inhibited the CCN3-induced increase of the migration and MMP-13 upregulation of chondrosarcoma cells. CCN3 stimulation increased the phosphorylation of focal adhesion kinase (FAK), PI3K, and Akt. In addition, NF-κB inhibitors also suppressed the cell migration and MMP-13 expression enhanced by CCN3. Moreover, CCN3 increased NF-κB luciferase activity and binding of p65 to the NF-κB element on the MMP-13 promoter. Taken together, our results indicate that CCN3 enhances the migration of chondrosarcoma cells by increasing MMP-13 expression through the αvβ3/αvβ5 integrin receptor, FAK, PI3K, Akt, p65, and NF-κB signal transduction pathway.

Exploiting the tumor microenvironment for theranostic imaging

The integration of chemistry and molecular biology with imaging is providing some of the most exciting opportunities in the treatment of cancer. The field of theranostic imaging, where diagnosis is combined with therapy, is particularly suitable for a disease as complex as cancer, especially now that genomic and proteomic profiling can provide an extensive 'fingerprint' of each tumor. Using this information, theranostic agents can be shaped for personalized treatment to target specific compartments, such as the tumor microenvironment (TME), whilst minimizing damage to normal tissue. These theranostic agents can also be used to target multiple pathways or networks by incorporating multiple small interfering RNAs (siRNAs) within a single agent. A decade ago genetic alterations were the primary focus in cancer research. Now it is apparent that the tumor physiological microenvironment, interactions between cancer cells and stromal cells, such as endothelial cells, fibroblasts and macrophages, the extracellular matrix (ECM), and a host of secreted factors and cytokines, influence progression to metastatic disease, aggressiveness and the response of the disease to treatment. In this review, we outline some of the characteristics of the TME, describe the theranostic agents currently available to target the TME and discuss the unique opportunities the TME provides for the design of novel theranostic agents for cancer therapy.

Analysis of angiogenic factors and cyclooxygenase-2 expression in cartilaginous tumors- clinical and histological correlation

OBJECTIVES

To study the role of angiogenesis and cyclooxygenase-2 expression in cartilaginous tumors and correlate these factors with prognosis.

INTRODUCTION

For chondrosarcoma, the histological grade is the current standard for predicting tumor outcome. However, a low-grade chondrosarcoma can follow an aggressive course-as monitored by sequential imaging techniques-even when it is histologically indistinguishable from an enchondroma. Therefore, additional tools are needed to help identify the biological potential of these tumors. The degree of angiogenesis that is induced by the tumor could assist in this task. Angiogenesis can be quantified by measuring the expression of vascular endothelial growth factor and CD34, and cyclooxygenase-2 can induce angiogenesis by stimulating the production of proangiogenic factors.

METHODS

In total, 21 enchondromas and 58 conventional chondrosarcomas were studied by examining the clinical and histopathological findings in conjunction with the immunostaining markers of angiogenesis and cyclooxygenase- 2 expression.

RESULTS

The significant variables that were associated with poor outcome were 1) higher-grade chondrosarcomas, 2) tumors that developed in flat bones, and 3) over-expression of CD34 (with a median count that was higher than 5.9 vessels in 5 high power fields). Moreover, CD34 expression (measured using the Chalkley method) revealed significantly higher microvessel density in flat bone chondrosarcomas.

DISCUSSION

Previous studies have shown a positive correlation between Chalkley microvessel density and histological grade; however, in our sample, we found that the former is predictive of the outcome. Chondrosarcomas in flat bones have been shown to correlate with a poor prognosis. We also found that CD34 microvessel density values were significantly higher in flat-bone chondrosarcomas. This could explain-at least in part-the more aggressive biological course that is taken by these tumors.

CONCLUSIONS

These results provide evidence that CD34 microvessel density in chondrosarcomas can be helpful in predicting patient outcome and may add to our understanding of chondrosarcoma pathogenesis.

Cyclooxygenase-2 in oncogenesis

Compelling experimental and clinical evidence supports the notion that cyclooxygenase-2, the inducible isoform of cyclooxygenase, plays a crucial role in oncogenesis. Clinical and epidemiological data indicate that aberrant regulation of cyclooxygenase-2 in certain solid tumors and hematological malignancies is associated with adverse clinical outcome. Moreover, findings extrapolated from experimental studies in cultured tumor cells and animal tumor models indicate that cyclooxygenase-2 critically influences all stages of tumor development from tumor initiation to tumor progression. Cyclooxygenase-2 elicits cell-autonomous effects on tumor cells resulting in stimulation of growth, increased cell survival, enhanced tumor cell invasiveness, stimulation of neovascularization, and tumor evasion from the host immune system. Additionally, the oncogenic effects of cyclooxygenase-2 stem from its unique ability to impact tumor cell surroundings and create a proinflammatory environment conducive for tumor development, growth and progression. The initial enthusiasm generated by the availability of cyclooxygenase-2 selective inhibitors for cancer prevention and therapy has been lessened by the severe cardiovascular adverse side effects associated with their long-term use, as well as by the mixed results of recent clinical trials evaluating the efficacy of cyclooxygenase-2 inhibitors in adjuvant chemotherapy. Therefore, our ability to efficiently target the oncogenic effects of cyclooxygenase-2 for therapeutic and preventive purposes strictly depends on a better understanding of the spatial and temporal aspects of its activation in tumor cells along with a clearer elucidation of the signaling networks whereby cyclooxygenase-2 affects tumor cells and their interactions with the tumor microenvironment. This knowledge has the potential of leading to the identification of novel cyclooxygenase-2-dependent molecular and signaling networks that can be exploited to improve cancer prevention and therapy.