Lysophosphatidic acid receptor 2/3-mediated IL-8-dependent angiogenesis in cervical cancer cells

Serum CXCL8 and CXCR2 as diagnostic biomarkers for noninvasive screening of cervical cancer

BACKGROUND

Cervical cancer (CC) is the fourth most frequently diagnosed cancer and the fourth leading cause of cancer-related death in women. Identifying new biomarkers for the early detection of CC is an essential requirement in this field. CXCL8 was originally discovered because of its role in inflammation by binding to CXCR1 and CXCR2; however, it is now known to play an important role in cancer. In this study, we aimed to evaluate the expression levels of potential biomarkers (CXCL8, CXCR1, and CXCR2) and to explore their diagnostic potential in CC.

METHODS

The expression levels of serum CXCL8, CXCR1, and CXCR2 were investigated by kit method on Immulite-1000 in 30 healthy volunteers, 30 precancerous patients and 70 CC patients.

RESULTS

The results indicated that the expression of CXCL8 and CXCR2 was significantly higher in the serum of CC patients than in healthy volunteers, similar to the well-established tumor marker (squamous-cell cancerantigen [SCC]). Receiver operating characteristic analyses showed that the combination of CXCL8, CXCR2, and SCC had the highest diagnostic sensitivity and area under the curve value. Meanwhile, the positive predictive value and negative predictive value were not very low. Moreover, high concentrations of CXCL8 and CXCR2 are associated with an increased risk of CC.

CONCLUSIONS

In conclusion, our data demonstrated that combined serum CXCL8, CXCR2, and SCC measurements are helpful for CC diagnosis and can be used as potential biomarkers for the early detection of CC. Cytokines, such as CXCL8 and CXCR2, can be easily measured in most university hospital laboratories and in some private laboratories with a routine test.

SPI1-related protein inhibits cervical cancer cell progression and prevents macrophage cell migration

AIM

The functions and molecular mechanisms of SPI1-related protein (SPIB) were examined in cervical cancer (CC) cells.

METHODS

Genes related to miscarriage and prognosis in CC were identified by Kaplan-Meier and differential expression analysis, respectively. Cell proliferation, apoptosis, migration, and invasion were examined by cell counting kit-8, flow cytometry, transwell migration, and transwell invasion assays, respectively. The potential functions and molecular mechanisms of SPIB in CC were speculated by gene set enrichment analysis (GSEA) analysis. The mRNA and protein levels of genes were examined by RT-qPCR and western blot assays, respectively. The effect of SPIB on macrophage cells was tested by macrophage recruitment assay and bioinformatics analysis.

RESULTS

A total of 753 dysregulated genes were identified in 88 TCGA CC samples with a history of one or more miscarriages versus 208 CC samples with no miscarriage history. Also, 91 genes related to CC prognosis were identified. SPIB, a gene related to both miscarriage and CC prognosis, inhibited Hela cell proliferation, migration, and invasion, and facilitated Hela cell apoptosis. GSEA analysis disclosed that SPIB might play vital roles in immunity, chemokine signaling pathway, and macrophage chemotaxis/activation in CC. Moreover, SPIB inhibited C-X-C motif chemokine ligand 8 (CXCL8), C-C motif chemokine ligand 17 (CCL17), and C-C motif chemokine ligand 25 (CCL25) expression in Hela cells, and SPIB overexpression in Hela cells hampered THP-1 cell migration. Higher SPIB expression was associated with less M2 macrophage infiltration in CC.

CONCLUSIONS

SPIB inhibited CC-cell progression and hindered macrophage cell migration in CC.

Lipid Signaling in Ocular Neovascularization

Vasculogenesis and angiogenesis play a crucial role in embryonic development. Pathological neovascularization in ocular tissues can lead to vision-threatening vascular diseases, including proliferative diabetic retinopathy, retinal vein occlusion, retinopathy of prematurity, choroidal neovascularization, and corneal neovascularization. Neovascularization involves various cellular processes and signaling pathways and is regulated by angiogenic factors such as vascular endothelial growth factor (VEGF) and hypoxia-inducible factor (HIF). Modulating these circuits may represent a promising strategy to treat ocular neovascular diseases. Lipid mediators derived from membrane lipids are abundantly present in most tissues and exert a wide range of biological functions by regulating various signaling pathways. In particular, glycerophospholipids, sphingolipids, and polyunsaturated fatty acids exert potent pro-angiogenic or anti-angiogenic effects, according to the findings of numerous preclinical and clinical studies. In this review, we summarize the current knowledge regarding the regulation of ocular neovascularization by lipid mediators and their metabolites. A better understanding of the effects of lipid signaling in neovascularization may provide novel therapeutic strategies to treat ocular neovascular diseases and other human disorders.

Interfering Human Papillomavirus E6/E7 Oncogenes in Cervical Cancer Cells Inhibits the Angiogenesis of Vascular Endothelial Cells via Increasing miR-377 in Cervical Cancer Cell-Derived Microvesicles

Background

The dysregulation of the human papillomavirus 18 E6 and E7 oncogenes plays a critical role in the angiogenesis of cervical cancer (CC), including the proliferation, migration, and tube formation of vascular endothelial cells. Interfering E6/E7 increases the number of CC cell-derived microvesicles (CC-MVs). Additionally, microRNAs (miRNAs) can modulate CC angiogenesis and can be encapsulated in MVs.

Objective

We aim to investigate whether E6/E7 affects CC angiogenesis via regulating miRNAs in CC-MVs.

Methods

CC-MVs were isolated from a CC cell line (HeLa) which were transfected with small interfering RNAs (siRNAs) against E6/E7 or co-transfected with miR-377 mimics/inhibitors. The expression of several miRNAs in CC-MVs was detected using quantitative real-time PCR. After co-incubating CC-MVs with human umbilical vein endothelial cells (HUVECs), cell proliferation, migration, and tube formation of HUVECs were determined using cell counting kit-8, transwell, and tube formation assays, respectively.

Results

MiR-377 was increased in E6/E7-interfering CC-MVs. Overexpressing miR-377 in CC-MVs suppressed HUVEC proliferation, migration, and tube formation. LPAR2, the cell surface G protein-coupled receptor, was the downstream target of miR-377 in HUVECs. The co-transfection of E6/E7 siRNAs and miR-377 inhibitors in CCs negated the effect of E6/E7 siRNAs on the elevation of miR-377 in CC-MVs. In HUVECs, the co-transfection of E6/E7 siRNAs and miR-377 inhibitors restored the LPAR2 expression which was reduced by the E6/E7 siRNA transfection. Meanwhile, miR-377 mimic reduced LPAR2 expression and inhibited HUVEC proliferation, migration, and tube formation, while such response was negated by LPAR2 overexpression.

Conclusion

Interfering E6/E7 increased miR-377 in CC-MVs, and overexpressing miR-377 in CC-MVs inhibited angiogenesis of HUVECs via reducing LPAR2.

Therapeutic Targeting of the Secreted Lysophospholipase D Autotaxin Suppresses Tuberous Sclerosis Complex-Associated Tumorigenesis

Tuberous sclerosis complex (TSC) is an autosomal dominant disease characterized by multiorgan hamartomas, including renal angiomyolipomas and pulmonary lymphangioleiomyomatosis (LAM). TSC2 deficiency leads to hyperactivation of mTOR Complex 1 (mTORC1), a master regulator of cell growth and metabolism. Phospholipid metabolism is dysregulated upon TSC2 loss, causing enhanced production of lysophosphatidylcholine (LPC) species by TSC2-deficient tumor cells. LPC is the major substrate of the secreted lysophospholipase D autotaxin (ATX), which generates two bioactive lipids, lysophosphatidic acid (LPA) and sphingosine-1-phosphate (S1P). We report here that ATX expression is upregulated in human renal angiomyolipoma-derived TSC2-deficient cells compared with TSC2 add-back cells. Inhibition of ATX via the clinically developed compound GLPG1690 suppressed TSC2-loss associated oncogenicity in vitro and in vivo and induced apoptosis in TSC2-deficient cells. GLPG1690 suppressed AKT and ERK1/2 signaling and profoundly impacted the transcriptome of these cells while inducing minor gene expression changes in TSC2 add-back cells. RNA-sequencing studies revealed transcriptomic signatures of LPA and S1P, suggesting an LPA/S1P-mediated reprogramming of the TSC lipidome. In addition, supplementation of LPA or S1P rescued proliferation and viability, neutral lipid content, and AKT or ERK1/2 signaling in human TSC2-deficient cells treated with GLPG1690. Importantly, TSC-associated renal angiomyolipomas have higher expression of LPA receptor 1 and S1P receptor 3 compared with normal kidney. These studies increase our understanding of TSC2-deficient cell metabolism, leading to novel potential therapeutic opportunities for TSC and LAM. SIGNIFICANCE: This study identifies activation of the ATX-LPA/S1P pathway as a novel mode of metabolic dysregulation upon TSC2 loss, highlighting critical roles for ATX in TSC2-deficient cell fitness and in TSC tumorigenesis.

Lysophosphatidic acid enhances breast cancer cells-mediated osteoclastogenesis

Lysophosphatidic acid (LPA) is known to play a critical role in breast cancer metastasis to bone. In this study, we tried to investigate any role of LPA in the regulation of osteoclastogenic cytokines from breast cancer cells and the possibility of these secretory factors in affecting osteoclastogenesis. Effect of secreted cytokines on osteoclastogenesis was analyzed by treating conditioned media from LPA-stimulated breast cancer cells to differentiating osteoclasts. Result demonstrated that IL-8 and IL-11 expression were upregulated in LPA-treated MDA-MB-231 cells. IL-8 was induced in both MDA-MB-231 and MDA-MB-468, however, IL-11 was induced only in MDA-MB-231, suggesting differential LPARs participation in the expression of these cytokines. Expression of IL-8 but not IL-11 was suppressed by inhibitors of PI3K, NFkB, ROCK and PKC pathways. In the case of PKC activation, it was observed that PKCδ and PKCμ might regulate LPA-induced expression of IL-11 and IL-8, respectively, by using specific PKC subtype inhibitors. Finally, conditioned Medium from LPA-stimulated breast cancer cells induced osteoclastogenesis. In conclusion, LPA induced the expression of osteolytic cytokines (IL-8 and IL-11) in breast cancer cells by involving different LPA receptors. Enhanced expression of IL-8 by LPA may be via ROCK, PKCu, PI3K, and NFkB signaling pathways, while enhanced expression of IL-11 might involve PKCδ signaling pathway. LPA has the ability to enhance breast cancer cells-mediated osteoclastogenesis by inducing the secretion of cytokines such as IL-8 and IL-11.

Bioactive lysolipids in cancer and angiogenesis

While normal angiogenesis is critical for development and tissue growth, pathological angiogenesis is important for the growth and spread of cancers by supplying nutrients and oxygen as well as providing a conduit for distant metastasis. The interaction among extracellular matrix molecules, tumor cells, endothelial cells, fibroblasts, and immune cells is critical in pathological angiogenesis, in which various angiogenic growth factors, chemokines, and lipid mediators produced from these cells as well as hypoxic microenvironment promote angiogenesis by regulating expression and/or activity of various related genes. Sphingosine 1-phosphate and lysophosphatidic acid, bioactive lipid mediators which act via specific G protein-coupled receptors, play critical roles in angiogenesis. In addition, other lipid mediators including prostaglandin E₂, lipoxin, and resolvins are produced in a stimulus-dependent manner and have pro- or anti-angiogenic effects, presumably through their specific GPCRs. Dysregulated lipid mediator signaling pathways are observed in the contxt of some tumors. This review will focus on LPA and S1P, two bioactive lipid mediators in their regulation of angiogenesis and cell migration that are critical for tumor growth and spread.

Bone marrow-derived mesenchymal stem cells induced by inflammatory cytokines produce angiogenetic factors and promote prostate cancer growth

Background

Prostate is susceptible to infection and pro-inflammatory agents in a man’s whole life. Chronic inflammation might play important roles in the development and progression of prostate cancer. Mesenchymal stem cells (MSCs) are often recruited to the tumor microenvironment due to local inflammation. We have asked whether stimulation of MSCs by pro-inflammatory cytokines could promote prostate tumor growth. The current study investigated the possible involvement of MSCs stimulated by pro-inflammatory cytokines in promotion and angiogenesis of prostate cancer through relative pathway in vitro and in vivo.

Methods

A syngeneic mouse model of C57 was established. The murine prostate cancer cells (RM-1) mixing with MSCs treated with tumor necrosis factor alpha (TNF-α) and interferon gamma (IFN-γ) or vehicle were subcutaneously injected into C57 mice. Tumor volume of C57 mouse model was estimated and serum level of platelet-derived growth factor (PDGF) and vascular endothelial growth factor (VEGF) was test by Enzyme-linked Immunosorbent Assay (ELISA). A hen egg test-chorioallantoic membrane (HET-CAM) assay was applied to test the effect of conditioned media of stimulated MSCs in chorioallantoic membrane angiogenesis. Short interfering RNA (siRNA) knocked down either hypoxia-inducible factor-1alpha (HIF-1α) or nuclear factor-erythroid-2-related factor 2 (NRF2) were employed. mRNA of PDGF and VEGF in MSCs, as well as NRF2 and HIF-1α was test by Real time polymerase chain reaction (PCR) analyses. Protein expression levels of PDGF and VEGF from conditioned medium, NRF2, HIF-1α, as well as PDGF and VEGF in MSCs were detected by Western blot analysis.

Results

MSCs treated with TNF-α and IFN-γ promote tumor growth in C57 syngeneic mouse model, correlating with increased serum level of PDGF, VEGF. HET-CAM assay shows the angiogenic effect of conditioned medium of MSCs pre-treated with the pro-inflammatory cytokines. mRNA and protein levels of two pro-angiogenic factors (PDGF and VEGF) and key hypoxia regulators (HIF-1α and NRF2) in MSCs were induced after MSCs’ pretreatment. siRNA knockdown either HIF-1α or NRF2 results reduction of PDGF and VEGF expression.

Conclusions

MSCs stimulated by pro-inflammatory cytokines increase the expression of PDGF and VEGF via the NRF2-HIF-1α pathway and accelerate prostate cancer growth in mice.

Electronic supplementary material

The online version of this article (10.1186/s12885-017-3879-z) contains supplementary material, which is available to authorized users.

Methyltransferase G9a promotes cervical cancer angiogenesis and decreases patient survival

Research suggests that the epigenetic regulator G9a, a H3K9 histone methyltransferase, is involved in cancer invasion and metastasis. Here we show that G9a is linked to cancer angiogenesis and poor patient survival. Invasive cervical cancer has a higher G9a expression than cancer precursors or normal epithelium. Pharmacological inhibition and genetic silencing of G9a suppresses H3K9 methylation, cancer cell proliferation, angiogenesis, and cancer cell invasion/migration, but not apoptosis. Microarray and quantitative reverse transcription polymerase chain reaction analyses reveal that G9a induces a cohort of angiogenic factors that include angiogenin, interleukin-8, and C-X-C motif chemokine ligand 16. Depressing G9a by either pharmacological inhibitor or gene knock down significantly reduces angiogenic factor expression. Moreover, promoting G9a gene expression augments transcription and angiogenic function. A luciferase reporter assay suggests that knockdown of G9a inhibits transcriptional activation of interleukin-8. G9a depletion suppresses xenograft tumor growth in mouse model, which is linked to a decrease in microvessel density and proliferating cell nuclear antigen expression. Clinically, higher G9a expression correlates with poorer survival for cancer patients. For patients’ primary tumors a positive correlation between G9a expression and microvessel density also exists. In addition to increasing tumor cell proliferation, G9a promotes tumor angiogenesis and reduces the patient survival rate. G9a may possess great value for targeted therapies.

Proliferation of mouse endometrial stromal cells in culture is highly sensitive to lysophosphatidic acid signaling

Endometrial stromal cells (ESCs) proliferate rapidly both in vivo and in vitro. Here we show that proliferation of ESCs in vitro is strongly dependent on lysophosphatidic acid (LPA) signaling. LPA is produced by autotaxin (ATX) and induces various kinds of cellular processes including migration, proliferation and inhibition of cell death possibly through six G protein-coupled receptors (LPA_1-6). We found that ESCs proliferated rapidly in vitro in an autocrine manner and that the proliferation was prominently suppressed by either an ATX inhibitor (ONO-8430506) or an LPA_1/3 antagonist (Ki16425). Among the cells lines tested, mouse ESCs were the most sensitive to these inhibitors. Proliferation of ESCs isolated from either LPA₁- or LPA₃-deficient mice was comparable to proliferation of ESCs isolated from control mice. An LPA receptor antagonist (AM095), which was revealed to be a dual LPA₁/LPA₃ antagonist, also suppressed the proliferation of ESCs. The present results show that LPA signaling has a critical role in the proliferation of ESCs, and that this role is possibly mediated redundantly by LPA₁ and LPA₃.

Lysophosphatidic acid rescues bone mesenchymal stem cells from hydrogen peroxide-induced apoptosis

The increase of reactive oxygen species in infracted heart significantly reduces the survival of donor mesenchymal stem cells, thereby attenuating the therapeutic efficacy for myocardial infarction. In our previous study, we demonstrated that lysophosphatidic acid (LPA) protects bone marrow-derived mesenchymal stem cells (BMSCs) against hypoxia and serum deprivation-induced apoptosis. However, whether LPA protects BMSCs from H2O2-induced apoptosis was not examined. In this study, we report that H2O2 induces rat BMSC apoptosis whereas LPA pre-treatment effectively protects BMSCs from H2O2-induced apoptosis. LPA protection of BMSC from the induced apoptosis is mediated mostly through LPA3 receptor. Furthermore, we found that membrane G protein Gi2 and Gi3 are involved in LPA-elicited anti-apoptotic effects through activation of ERK1/2- and PI3 K-pathways. Additionally, H2O2 increases levels of type II of light chain 3B (LC3B II), an autophagy marker, and H2O2-induced autophagy thus protected BMSCs from apoptosis. LPA further increases the expression of LC3B II in the presence of H2O2. In contrast, autophagy flux inhibitor bafilomycin A1 has no effect on LPA's protection of BMSC from H2O2-induced apoptosis. Taken together, our data suggest that LPA rescues H2O2-induced apoptosis mainly by interacting with Gi-coupled LPA3, resulting activation of the ERK1/2- and PI3 K/AKT-pathways and inhibition caspase-3 cleavage, and LPA protection of BMSCs against the apoptosis is independent of it induced autophagy.

Lysophosphatidic Acid Inhibits Apoptosis Induced by Cisplatin in Cervical Cancer Cells

Cervical cancer is the second most common cause of cancer death in women worldwide. Lysophosphatidic acid (LPA) level has been found significantly increased in the serum of patients with ovarian, cervical, and colon cancers. LPA level in cervical cancer patients is significantly higher than in healthy controls. LPA receptors were found highly expressed in cervical cancer cells, suggesting LPA may play a role in the development of cervical cancer. The aim of this study is to investigate the effect of LPA on the apoptosis induced by cisplatin (DDP) in cervical cancer cell line and the underlying changes in signaling pathways. Our study found that cisplatin induced apoptosis of Hela cell through inhibiting expression of Bcl-2, upregulating the expression of Bax, Fas-L, and the enzyme activity of caspase-3 (p < 0.05); LPA significantly provided protection against the apoptosis induced by cisplatin by inhibiting the above alterations in apoptotic factor caused by cisplatin (p < 0.05). Moreover, PI3K/AKT pathway was found to be important for the LPA antiapoptosis effect, and administration of PI3K/AKT partially reversed the LPA-mediated protection against cisplatin-induced apoptosis (p < 0.05). These findings have shed new lights on the LPA bioactivity in cervical cancer cells and pointed to a possible sensitization scheme through combined administration of PI3K inhibitor and cisplatin for better treatment of cervical cancer patients, especially those with elevated LPA levels.

In situ increased chemokine expression in human cervical intraepithelial neoplasia

Chemokines play a role in tumor-inflammation and angiogenesis that could be involved in tumor progression. Monocyte chemoattractant protein-1 (MCP-1), Interleukin-8 (IL-8) and macrophage inflammatory proteins (MIP) have been identified in tumor tissues of patients with different neoplasms. Therefore, the aim of the current study was to investigate the expressions of MCP-1, IL-8 and MIP-1α, mononuclear leukocyte infiltration and leukocyte/chemokine expressions in cervical tissues from patients with cervical intraepithelial neoplasia (CIN) and controls. MCP-1, IL-8 and MIP-1α expressions and leukocyte infiltration were determined by indirect immunofluorescence in cervix biopsies from CIN patients (n=65) and 7 normal controls. Increased expressions of MCP-1 and IL-8 in CIN were observed. Increment of lymphocyte infiltration and coexpression of CD3/MCP-1 and CD3/IL-8 were found in CIN. CD3/MCP-1 cell percentage was found decreased and CD3/IL-8 percentage increased according to the CIN evolution. MIP-1α remained similar to control values. The increased expression of MCP-1 and IL-8 in cervical neoplasia may lead to tumor progression.

Regulation of T cell motility in vitro and in vivo by LPA and LPA2

Lysophosphatidic acid (LPA) and the LPA-generating enzyme autotaxin (ATX) have been implicated in lymphocyte trafficking and the regulation of lymphocyte entry into lymph nodes. High local concentrations of LPA are thought to be present in lymph node high endothelial venules, suggesting a direct influence of LPA on cell migration. However, little is known about the mechanism of action of LPA, and more work is needed to define the expression and function of the six known G protein-coupled receptors (LPA 1-6) in T cells. We studied the effects of 18∶1 and 16∶0 LPA on naïve CD4+ T cell migration and show that LPA induces CD4+ T cell chemorepulsion in a Transwell system, and also improves the quality of non-directed migration on ICAM-1 and CCL21 coated plates. Using intravital two-photon microscopy, lpa2-/- CD4+ T cells display a striking defect in early migratory behavior at HEVs and in lymph nodes. However, later homeostatic recirculation and LPA-directed migration in vitro were unaffected by loss of lpa2. Taken together, these data highlight a previously unsuspected and non-redundant role for LPA2 in intranodal T cell motility, and suggest that specific functions of LPA may be manipulated by targeting T cell LPA receptors.

Lysophosphatidic acid enhanced the angiogenic capability of human chondrocytes by regulating Gi/NF-kB-dependent angiogenic factor expression

Lysophosphatidic acid (LPA) has been found to mediate myeloid differentiation, stimulate osteogenesis, alter cell proliferation and migration, and inhibit apoptosis in chondrocytes. The effect of LPA on the angiogenic capability of chondrocytes is not clear. This study aimed to investigate its effect on the angiogenic capability of human chondrocytes and the underlying mechanism of these effects. Human chondrocyte cell line, CHON-001, commercialized human chondrocytes (HC) derived from normal human articular cartilage, and human vascular endothelial cells (HUVECs) were used as cell models in this study. The angiogenic capability of chondrocytes was determined by capillary tube formation, monolayer permeability, cell migration, and cell proliferation. An angiogenesis protein array kit was used to evaluate the secretion of angiogenic factors in conditioned medium. Angiogenin, insulin-like growth factor-binding protein 1 (IGFBP-1), interleukin (IL)-8, monocyte chemoattractant protein-1 (MCP-1), matrix metalloproteinase (MMP)-9, and vascular endothelial growth factor (VEGF) mRNA and protein expressions were evaluated by Q-RT-PCR and EIA, respectively. LPA receptor (LPAR) expression was determined by RT-PCR. Signaling pathways were clarified using inhibitors, Western blot analysis, and reporter assays. The LPA treatment promoted the angiogenic capability of CHON-001 cells and HC, resulting in enhanced HUVEC capillary tube formation, monolayer permeability, migration, and cell growth. Angiogenin, IGFBP-1, IL-8, MCP-1, MMP-9, and VEGF mRNA and protein expressions were significantly enhanced in LPA-treated chondrocytes. LPA2, 3, 4 and 6 were expressed in CHON-001 and HC cells. Pretreatment with the Gi/o type G protein inhibitor, pertussis toxin (PTX), and the NF-kB inhibitor, PDTC, significantly inhibited LPA-induced angiogenin, IGFBP-1, IL-8, MCP-1, MMP-9, and VEGF expressions in chondrocytes. The PTX pretreatment also inhibited LPA-mediated NF-kB activation, suggesting the presence of active Gi/NF-kB signaling in CHON-001 and HC cells. The effect of LPA on the angiogenesis-inducing capacity of chondrocytes may be due to the increased angiogenesis factor expression via the Gi/NF-kB signaling pathway.

Cervical carcinoma cells stimulate the angiogenesis through TSLP promoting growth and activation of vascular endothelial cells

PROBLEM

To explore whether cervical carcinomas cells-derived thymic stromal lymphopoietin (TSLP) modulates the biologic behavior of vascular endothelial cells and herein participates in the angiogenesis in the cervical cancer pathogenesis.

METHOD OF STUDY

We analyzed expression of TSLP and its receptor (TSLPR) in cervical cancer cells by immunohistochemistry, ELISA, and flow cytometry, respectively. We further investigated the effects of TSLP on the proliferation, apoptosis, activation, and angiogenesis in vitro of human umbilical vein endothelial cells (HUVECs).

RESULTS

It has been found that the cervical cancer cells translate TSLP and endothelial cells express TSLPR in cervical cancer tissues. Both HeLa and CaSki cells secret TSLP in a time-dependent manner, and the ratio of TSLPR-positive HUVECs is about 30%. It has been showed that recombinant human TSLP (rhTSLP) can significantly increase Ki67 and CD62E expression in HUVECs and interleukin-6 (IL-6) levels from HeLa and CaSki cells; on the contrary, anti-human TSLP or TSLPR neutralizing antibody down-regulates the expression of Ki67, angiogenesis-relative molecules CD62E, and CD105 in HUVECs cocultured with HeLa or CasKi cells and inhibits IL-6 secretion from HeLa and CaSki cells. Moreover, both rhTSLP and endogenous TSLP from HeLa or CaSki cells obviously stimulate the proliferation, activation, and angiogenesis, but not influence the apoptosis of HUVECs in vitro.

CONCLUSION

This study has demonstrated that TSLP secreted by cervical carcinomas cells is involved in the angiogenesis of cervical cancer in a paracrine manner.

Comparing the differential effects of LPA on the barrier function of human pulmonary endothelial cells

Lysophosphatidic acid (LPA) is a class of bioactive lyso-phospholipid that mediates most of its biological effects through a family of G protein-coupled receptors of which six have been identified. The role of the LPA pathway in driving chronic lung diseases such as idiopathic pulmonary fibrosis (IPF) has gained considerable academic and industry attention. Modulation of the pulmonary artery endothelial barrier function by the LPA1 receptor has been shown to drive pulmonary fibrosis in murine models of disease. The purpose of this study was (i) to assess the effect of LPA on the barrier function of human pulmonary arterial (HPAEC) and microvascular (HMVEC) endothelial cells and (ii) to identify the LPA receptor subtype(s) responsible for changes in human pulmonary endothelial cell permeability using LPA receptor antagonists and siRNA technology. Analysis of the LPA receptor subtype expression demonstrated predominant expression of LPA2 and LPA6 receptor subtypes in both HPAECs and HMVECs. HPAECs also exhibit low expression of LPA1, LPA3, and LPA4 receptor subtypes. Treatment of cells with increasing concentrations of LPA caused loss of barrier function in HPAECs but not HMVECs, despite both cell types exhibiting very similar LPA receptor expression profiles. The LPA-mediated loss of barrier function in HPAECs appears to be independent of the LPA1 receptor and likely to be mediated via the LPA6 receptor although we cannot exclude an additional role for the LPA2 and LPA4 receptors in mediating these effects. These results suggest cell-specific mechanisms exist in human pulmonary endothelial cells to permit regulation of barrier function downstream of LPA receptors. More importantly, our data indicate that selective LPA1 receptor antagonism may be insufficient for therapeutic use in pulmonary diseases where impaired endothelial barrier function is related to disease initiation and progression.