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Thromboxane (TX) and prostaglandins are metabolites of arachidonic acid, a twenty-carbon unsaturated fatty acid, and have a variety of actions that are exerted via specific receptors. Angiogenesis is defined as the formation of new blood vessels from pre-existing vascular beds and is a critical component of pathological conditions, including inflammation and cancer. Lymphatic vessels play crucial roles in the regulation of interstitial fluid, immune surveillance, and the absorption of dietary fat from the intestine; and they are also involved in the pathogenesis of various diseases. Similar to angiogenesis, lymphangiogenesis, the formation of new lymphatic vessels, is a critical component of pathological conditions. The TP-dependent accumulation of platelets in microvessels has been reported to enhance angiogenesis under pathological conditions. Although the roles of some growth factors and cytokines in angiogenesis and lymphangiogenesis have been well characterized, accumulating evidence suggests that TX induces the production of proangiogenic and prolymphangiogenic factors through the activation of adenylate cyclase, and upregulates angiogenesis and lymphangiogenesis under disease conditions. In this review, we discuss the role of TX as a regulator of angiogenesis and lymphangiogenesis, and its emerging importance as a therapeutic target., Competing Interests: Declaration of Competing Interest All the authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023. Published by Elsevier Masson SAS.)

In the intestine, the formation of new lymphatic vessels from pre-existing lymphatic vasculature (lymphangiogenesis) is related to the progression of inflammatory bowel disease (IBD). However, it remains unclear whether lymphangiogenesis contributes to mucosal repair after acute colitis. Prostaglandin Ereceptor EP4 suppresses the development of experimental colitis. In this study, we investigated whether EP4 exerts this effect by contributing to lymphangiogenesis, in turn promoting mucosal tissue repair, following acute colitis. We elicited experimental colitis in male C57/BL6 mice by administering dextran sulphate sodium (DSS) via the drinking water for 5 days, followed by normal water for 9 additional days. From Day 5 through Day 13, the experimental mice received a daily dose of EP4-selective agonist, EP4-selective antagonist, or vehicle. On Day 14, mice treated with vehicle had recovered 95 % of body weight and exhibited moderate increases in disease activity and histological score relative to untreated controls. Compared with vehicle, post-treatment with EP4 antagonist increased signs of colitis, colonic tissue destruction, and CD11b + cell infiltration, associated with elevated lymphatic vessel density (LVD) and reduced percentage of lymphatic vessel area (LVA%). By contrast, post-treatment with EP4 agonist improved disease activity, suppressed CD11b + infiltration, and decreased levels of inflammatory cytokines; these changes were associated with upregulation of lymphatic growth factors and lymphangiogenesis, as evidenced by increases in LVA% and lymphatic drainage function. Inhibition of vascular endothelial growth factor receptor 3 (VEGFR3) caused a delay in mucosal repair, accompanied by impaired lymphangiogenesis. These results suggest that EP4 stimulation aids in mucosal repair from DSS-induced acute colitis by promoting lymphangiogenesis., Competing Interests: Declaration of Competing Interest The authors declare that they have no conflicts of interest related to this work., (Copyright © 2020 The Authors. Published by Elsevier Masson SAS.. All rights reserved.)

Background: Accumulation of myeloid-derived suppressor cells (MDSCs) to tumors is related to cancer prognosis. We investigated the contribution of host stromal microsomal prostaglandin E synthase-1 (mPGES-1) to the accumulation of MDSCs in metastasized lungs of prostate cancer in mice., Material and Methods: Eight-week-old male C57Bl/6 wild type (WT) mice and mPGES-1 knock out mice (mPGES-1KO) were injected with RM9 murine prostate cancer cell line (5 × 10 6 cells/mL). Lung metastasis was evaluated by the number of colonies, the weight of the lung, and the number of MDSCs (CD11b + Gr1 + cells) in the lung., Results: Intravenous injections of RM9, a murine prostate cancer cell line to WT mice revealed that lung metastasis and accumulation of MDCSs were suppressed with treatments with a Gr1 antibody, a COX-2 inhibitor, and an mPGES-1 inhibitor. Lung metastasis and accumulation of CD11b + Gr1 + MDSCs were suppressed in mPGES-1KO mice. The mRNA level of stromal cell-derived factor-1 (SDF-1) in the lung and the number of accumulated SDF-1-expressing CD11b + Gr1 + MDSCs were elevated at an early stage in lung metastasis of C-X-C chemokine receptor type 4 (CXCR4)-expressing RM9 in an mPGES-1-dependent manner. The number of CXCR4-expressing CD11b + Gr1 + MDSCs in WT mice was higher than that in mPGES-1KO mice. RM9 lung metastasis and accumulation of CD11b + Gr1 + MDSCs were suppressed by CXCR4 antibody in WT mice but not in mPGES-1KO. WT mice transplanted with mPGES-1 KO bone marrow (BM) showed a significant reduction in lung metastasis and accumulation of CD11b + Gr1 + MDSCs., Conclusion: These results suggest that mPGES-1 enhances tumor metastasis by inducing accumulation of BM-derived MDSCs. Selective mPGES-1 inhibitors might, therefore, represent valuable therapeutic tools for the suppression of tumor metastasis., (Copyright © 2019. Published by Elsevier Masson SAS.)

Background: Idiopathic pulmonary fibrosis (IPF) is a lethal lung disease with a poor prognosis. Fibroblast proliferation amplifies extracellular matrix deposition and increases angiogenesis. Vascular endothelial growth factor (VEGF) is one of the most potent angiogenic factors. VEGF interacts with VEGF receptors (VEGFR1 and VEGFR2). A previous study showed that VEGFR1 tyrosine kinase (TK) signaling induced blood flow recovery mediated by bone marrow (BM)-derived stem cells. We hypothesized that VEGFR1-TK signaling might be related to pulmonary fibrosis., Material and Methods: Six-week-old male C57Bl/6 wild-type (WT) mice and VEGFR1 TK knockout mice (TKKO mice) were treated with a single intratracheal injection of bleomycin (BLM; 0.1 μg in 50 μl saline) or vehicle (saline; 50 μl). Lung fibrosis was evaluated by histology, real-time PCR and ELISA for pro-fibrotic factors, and assessment of lung mechanics., Results: The fibrotic area in the lung and the lung elastance were significantly reduced in TKKO mice (P < 0.01). The expression of the fibrosis-related factors type I collagen, S100A4, and transforming growth factor (TGF)-β was also significantly reduced in TKKO mice on day 21 after BLM injection. TKKO mice also had significantly lower levels of stromal cell-derived factor (SDF)-1 in the lungs and plasma on days 14 and 21 after BLM treatment (P < 0.05). Moreover, the expression of C-X-C chemokine receptor type 7 (CXCR7) and CXCR4, the receptors for SDF-1, was also suppressed in TKKO mice. Immunohistochemical analysis showed that treatment with a CXCR4 antibody decreased the accumulation of VEGFR1 + cells in the lung in WT mice but not in TKKO mice., Conclusion: These results suggest that VEGFR1 TK signaling promotes BLM-induced pulmonary fibrosis by activating the SDF-1/CXCR4 axis in infiltrating VEGFR1 + cells., (Copyright © 2019. Published by Elsevier Masson SAS.)

Background: Ulcerative Colitis (UC) is an inflammatory bowel disease that affects the colon. The development of UC is regulated by immune cells. Previously, we showed that vascular endothelial growth factor receptor 1 (VEGFR1) tyrosine kinase (TK) signaling induces healing of mucosal damage by recruiting VEGFR1 + cells appear to be lineage monocyte cells. Recent studies show that development of UC correlates with the number of regulatory T cells (Tregs). Here, we investigated whether VEGFR1-TK signaling induces healing of UC via accumulation of Tregs or not., Method: Acute colitis was induced in C57/Bl6N (wild-type [WT]) and VEGFR1 T K knockout (VEGFR1 T K -/- ) mice by administration of 2.0% dextran sulfate sodium (DSS)., Results: Total colon length in VEGFR1 T K -/- mice was shorter than that in WT mice. The ulcer length and the disease activity index (DAI) score were significantly higher in VEGFR1 T K -/- mice than in WT mice, whereas CD31 mRNA and protein levels were significantly lower. Accumulation of forkhead box P3 + (Foxp3 + ) VEGFR1 + Tregs was lower in VEGFR1 T K -/- mice, as was expression of interleukin (IL)-10 and transforming growth factor (TGF)-β. The survival rate of WT mice treated with an anti-folate receptor 4 (FR4) antibody was 40%, while that of WT mice treated with control IgG was 90%. Moreover, WT mice treated with a neutralizing antibody against C-X-C chemokine receptor type 4 (CXCR4) showed significantly shorter colon length than WT with control antibody. In VEGFR1 T K -/- , infiltration of Foxp3 + Tregs expressing VEGFR1 and CXCR4 into ulcerated areas was lower than that in WT mice., Conclusion: VEGFR1-TK signaling plays a critical role in UC healing and angiogenesis via accumulation of VEGFR1 + CXCR4 + Foxp3 + Tregs in ulcerated tissue. (264 words)., (Copyright © 2018. Published by Elsevier Masson SAS.)

The vascular endothelial growth factor (VEGF) family has a key role in the formation of blood vessels and lymphatics. Among the members of this family, VEGF-C is one of the most important factors involved in lymphangiogenesis via binding with two receptors (vascular endothelial growth factor receptor-2 and -3: VEGFR-2 and VEGFR-3). Soluble VEGFR-2 (sVEGFR-2) has a role in maintaining the alymphatic state of the cornea associated with binding to VEGF-C, and selectively inhibits lymphangiogenesis but not angiogenesis. In this study, we introduced sVEGFR-2 into lung cancer cells and evaluated the influence on tumor progression and on genes regulating lymphatic formation and metastasis in vivo. A retroviral vector was used to introduce the sVEGFR-2 gene into Lewis lung carcinoma cells (LLC), which were designated as LLC-sVEGFR-2 cells. Proteins secreted into the culture supernatant by these cells were detected by western blotting using specific antibodies. To examine lymphangiogenesis by primary lung cancer in vivo, LLC-sVEGFR-2 cells were subcutaneously injected into C57BL/6 mice. At 14days after injection, immunohistochemistry was performed using an antibody directed against lymphatic vessel endothelial hyaluronan receptor 1 (LYVE-1), a marker of lymphatics. Expression of mRNA for VEGFR-2, VEGFR-3 and matrix metalloproteinases (MMPs) was also determined by real-time PCR. Furthermore, LLC-sVEGFR-2 cells were directly inoculated into the left lung in C57BL/6 mice and the number of micro-metastases in pulmonary lymph nodes was determined. Introduction of sVEGFR-2 into LLC cells resulted in secretion of sVEGFR-2 protein into the culture supernatant. There were fewer LYVE-1 positive lymphatics after inoculation of LLC-sVEGFR-2 into mice compared with the control group. In addition, VEGFR-2, VEGFR-3, and MMPs gene expression was suppressed in the primary tumors of the LLC-sVEGFR-2 group compared with the control group. Furthermore, there were fewer micro-metastases in the pulmonary lymph nodes of the LLC-sVEGFR-2 group compared with the control group after cells were directly inoculated into the lung. These findings indicate that introduction of sVEGFR-2 suppressed lymphangiogenesis in primary lung cancer and also suppressed lymphogenic metastasis by inhibiting VEGF-C, followed by down-regulation of VEGFR-2, VEGFR-3 and MMPs. Accordingly, sVEGFR-2 might be a promising target for treatment of cancer by regulating lymphangiogenesis and lymphogenic metastasis., (Copyright © 2016 Elsevier Masson SAS. All rights reserved.)

Background: Vascular endothelial growth factor (VEGF)-A binds to both VEGF receptor (VEGFR)-1 and VEGFR-2, thereby promoting angiogenesis. It is widely accepted that VEGF-A, especially VEGFR-2, is a central player in angiogenesis, however the role of VEGFR-1 in angiogenesis remains unclear. The present study was conducted to examine the role of VEGFR-1 signaling in angiogenesis, using a quantitative in vivo angiogenesis model., Methods: Polyurethane sponge disks were implanted into dorsal subcutaneous tissue of mice. Angiogenesis was estimated by determining the number of CD31(+) vessels by immunohistochemical analysis. The expression of pro-angiogenic factors was quantified by reverse transcription quantitative polymerase chain reaction., Results: Compared to control IgG-treated mice, the number of CD31(+) vessels in the sponge implant was significantly suppressed in anti-VEGF-A neutralizing antibody-treated mice. CD31(+) vessel counts were suppressed in VEGFR-1 tyrosine kinase knockout (TKKO) mice, at the same level as in VEGFR-2 tyrosine kinase inhibitor (ZD6474)-treated mice compared to wild-type (WT) mice. The accumulation of VEGFR-1(+) cells in granulation tissue was significantly suppressed in VEGFR-1 TKKO mice compared to WT mice. In addition, expression of the pro-angiogenic growth factors, VEGF-A, matrix metalloproteinase-2, interleukin-6, and basic fibroblast growth factor in granulation tissue was suppressed in VEGFR-1 TKKO mice. A bone marrow (BM) transplantation experiment showed that the number of VEGFR-1(+) BM-derived cells and angiogenesis were significantly suppressed in VEGFR-1 TKKO mice transplanted with green fluorescent protein (GFP)(+) VEGFR-1 TKKO BM compared to WT mice transplanted with GFP(+) WT BM., Conclusions: These results suggest that the VEGFR-1 tyrosine kinase signaling has an effect on angiogenesis. A selective VEGFR-1 agonist/antagonist could be a candidate therapeutic agent to control angiogenesis with recruitment of BM cells., (Copyright © 2016 Elsevier Masson SAS. All rights reserved.)

Unilateral ureteral obstruction (UUO) induced tubulointerstitial fibrosis in kidneys mimics the pathogenesis of chronic kidney diseases and is considered a suitable model for studying the mechanisms leading to fibrosis. To study the role of cyclooxygenase-2 (COX-2) in kidney fibrosis, we investigated whether a selective COX-2 inhibitor, celecoxib, affected renal interstitial fibrosis during UUO in mice. To induce UUO, the left proximal ureter was ligated in male C57BL/6 mice. The mice were fed a diet with or without celecoxib from the day of UUO induction. Following UUO, the renal pelvis was observed to be dilated and the kidney cortex was significantly thinner than that of sham-operated mice. Immunofluorescent staining of type I, III, and IV collagen in UUO kidneys revealed that interstitial collagen deposition was significantly increased in the celecoxib-treated group. Expression of type I, III, and IV collagen in UUO kidneys was also significantly higher in the celecoxib-treated group than in the vehicle-treated group. In the celecoxib-treated group, mRNA levels of TGF-β/FGF-2 were also significantly higher than those in the vehicle-treated group. The present study demonstrates that COX-2 plays a protective role against fibrosis in UUO kidneys and suggests that supplementation of COX-2 products, such as PG analogues, will be a good option for preventing interstitial fibrosis., (Copyright © 2015 Elsevier Masson SAS. All rights reserved.)

Background: Diabetes mellitus inhibits wound-induced angiogenesis, impairing the wound healing process and leading to the development of chronic wounds. Impaired healing of diabetic wounds is caused by persistent pro-inflammatory macrophages recruited to the granulation tissue; however, little is known about the phenotype of the macrophages involved in diabetic wound healing. The present study was conducted to examine the involvement of macrophages in impaired wound healing using streptozotocin (STZ)-induced diabetic mice., Methods: Full-thickness skin wounds were created on the backs of mice treated with STZ or vehicle., Results: Compared with controls, wound healing and angiogenesis were suppressed in STZ-treated mice, with attenuated expression of vascular endothelial growth factor (VEGF) and fibroblast growth factor (FGF)-2 in wound granulation tissue. STZ-treated mice exhibited enhanced recruitment of classically activated macrophages (M1) expressing inducible nitric oxide synthase (iNOS) and suppressed recruitment of alternatively activated macrophages (M2) expressing transforming growth factor-beta-1 (TGF-β1). Treatment of diabetic mice with TGF-β1 restored wound healing and angiogenesis and normalized M1/M2 macrophage polarization in the granulation tissue., Conclusions: These results suggest that an imbalance of macrophage phenotypes contributes to impaired wound healing in STZ-induced diabetic mice, and treatment with cytokines derived from M2 macrophages may be an effective therapeutic strategy to increase angiogenesis and promote healing of diabetic wounds., (Copyright © 2014 Elsevier Masson SAS. All rights reserved.)

Vascular complications such as foot ulcers are a hallmark of diabetes mellitus (DM), although the molecular mechanisms that underlie vascular dysfunction remain unclear. Herein, we show that angiogenesis, which is indispensable to the healing of ulcers, is suppressed in polyurethane sponge implants in mice with DM and reduced proangiogenic signaling. DM was induced in male C57BL/6 mice by intraperitoneal injection of streptozotocin (100mg/kg). Polyurethane sponge disks were implanted into subcutaneous tissues on the backs of mice, and angiogenesis and expression of related factors were analyzed in sponge granulation tissues. Densities of platelet endothelial cell adhesion molecule-1 (PECAM-1)-positive vascular structures and PECAM-1 expression in sponge granulation tissues were increased over time in control mice and reduced in diabetic mice. The reductions in diabetic mice were accompanied by reduced expression of inducible cyclo-oxygenase-2 and microsomal prostaglandin E synthase-1. The prostaglandin E receptor subtype EP3 was downregulated in sponge granulation tissues in diabetic mice, whereas EP1, EP2, and EP4 were not. The expression of the proangiogenic growth factor vascular endothelial growth factor (VEGF)-A and the chemokine stromal cell-derived factor-1 (SDF-1) were both reduced in diabetic mice. Treatment of diabetic mice with a selective agonist of EP3, ONO-AE 248 (30 nmol/site/day, topical injection), reversed suppression of angiogenesis in diabetic mice. These results indicate that proangiogenic EP3 signaling is suppressed in diabetic mice with reduced expression of VEGF and SDF-1. Stimulation of EP3 signaling restored angiogenesis in a sponge implant model in mice with DM. This suggests that topical application of an EP3 agonist could be a novel strategy to treat foot ulcers in patients with DM., (Copyright © 2014 Elsevier Masson SAS. All rights reserved.)

Cyclooxygenase-2 (COX-2) is known to correlate with a poor prognosis of prostate cancer and contribute to tumor metastasis. However, the precise mechanism of this phenomenon remains unknown. We have previously reported that host stromal microsomal prostaglandin E synthase-1 (mPGES-1) appeared critical for tumor-associated angiogenesis and tumor growth. Here, we tested whether or not mPGES-1 has a critical role in lung metastasis formation of prostate cancer. Murine prostate cancer cells (RM9) were intravenously injected and lung metastasis was estimated by counting colonies in the lungs. Mice treated with a selective COX-2 inhibitor, celocoxib, were suppressed lung metastasis compared to vehicle mice. This lung metastasis formation was also reduced in mPGES-1 knockout (mPGES-1 KO) mice, compared with wild type (WT) mice. This was accompanied with reduced angiogenesis around the metastasized colonies of RM9. Plasma protein levels and metastasized lung tissue mRNA levels of vascular endothelial growth factor (VEGF) and stromal cell derived factor-1 (SDF-1) were significantly suppressed in mPGES-1 KO mice in comparison with WT mice. In addition, the expressions of matrix metalloproteinases (MMP)-9, and metalloproteinases (MMP)-2 were down-regulated in metastatic lungs in mPGES-1 KO mice. These results suggested that host mPGES-1 was essential for MMP-2 and MMP-9 up-regulation that enhances tumor metastasis. mPGES-1 appears to be critical for tumor metastasis in prostate cancers. mPGES-1 inhibitors may be useful to protect against prostate cancer metastasis., (Copyright © 2013 Elsevier Masson SAS. All rights reserved.)

Background: Lung cancer is the main cause of cancer-related death worldwide. The high mortality is probably attributable to early metastasis; however, the mechanism underlying metastasis to regional lymph nodes is still unknown. Cyclooxygenase (COX)-derived prostaglandin E2 (PGE2) induces tumor growth and metastasis and is associated with a poor prognosis. The present study investigated the effect of an authentic COX inhibitor, aspirin, on regional lymph node metastasis during the development of lung cancer in mice., Methods: An orthotopic intrapulmonary implantation model based on male C57BL/6 (6-8-weeks-old) mice was used. The lungs were injected with a solution containing Lewis lung carcinoma (LLC) cells overexpressing green fluorescent protein (GFP) and BD Matrigel(®). The effect of aspirin on mediastinal lymph node metastasis of LCC cells from the primary injection sites was then examined., Results: The implantation process took approximately 30 s per mouse and operative mortality was 10%. Single pulmonary nodules developed at the implanted site in 95% of animals, and regional mediastinal lymph node metastasis was observed at 14 days post-LLC-GFP cell injection in all mice that formed a primary lung tumor. The mean survival time of mice injected with LLC-GFP cells was 15±3 days (range, 12-22 days). Histopathological analysis revealed that no metastatic tumors developed in the regional mediastinal lymph nodes by Day 10-12 post-LLC-GFP cell injection and no metastasis to distant organs or distant lymph nodes was observed by Day 21 post-injection. Oral administration of aspirin (100 mg/kg, twice a day) after LLC-GFP cell injection inhibited metastasis to the regional lymph nodes, with no significant suppression of primary tumor growth in the lungs. Aspirin treatment led to a significant reduction in mortality (P<0.0001)., Conclusions: The present lymph node metastasis model is useful for evaluating the efficacy of agents that inhibit tumor metastasis to the regional lymph nodes. Aspirin reduced the metastasis of LLC-GFP cells injection to the regional lymph nodes, with a significant reduction in mortality. These findings suggested that COX inhibitors have potential for preventing lymph node metastasis., (Copyright © 2013 Elsevier Masson SAS. All rights reserved.)

Background: Ulcer healing is a complex process, which involves cell migration, proliferation, angiogenesis and re-epithelialization. Several growth factors have been implicated in this process but the precise mechanism is not well understood. This study examined the involvement of VEGFR1 signaling in the gastric ulcer healing., Methods: Gastric ulcers were induced by the serosal application of 100% acetic acid, and the areas of the ulcers were measured thereafter., Results: The healing of acetic acid induced ulcers and the progenitor cells expressing CXCR4(+)VEGFR1(+) cell were significantly delayed in NSAID treated mice. The areas of the ulcer was significantly suppressed in tyrosine kinase-deficient VEGFR1 mice (VEGFR1TKKO) compared with wild type (WT) mice. The plasma level of SDF-1 and stem cell factor (SCF) and bone marrow level of pro-matrix metallopeptidase 9 (pro-MMP-9) were significantly reduced in VEGFR1TKKO mice. In VEGFR1 TKKOmice, the progenitor cells expressing CXCR4(+)VEGFR1(+) cell from bone marrow and the recruitment of these cells in healing ulcer were suppressed. Furthermore, VEGFR1 TKKO mice treated with NSAID did not suppress gastric ulcer healing compared to vehicle mice. These results suggested that NSAID suppressed VEGFR1 TK signaling plays a critical role in ulcer healing through mobilization of CXCR4(+)VEGFR1(+) cells., Conclusion: VEGFR1 signaling is required for healing of NSAID induced gastric ulcer and angiogenesis with increased recruitment of CXCR4(+)VEGFR1(+) cells to the ulcerative lesion., (Copyright © 2013. Published by Elsevier Masson SAS.)

Fifteen-deoxy-Δ(12,14)-PGJ(2) (15d-PGJ(2)) is one of non-enzymatically converted metabolite from prostaglandin D(2) (PGD(2)). Anti-tumor effects of 15d-PGJ(2) in various tumors are partially known, but the detail of in vivo mechanisms of action is still unclear. In this study, we investigated the effects of 15d-PGJ(2) and PGD(2) on murine prostate cancer in vitro and in vivo. Murine prostate cancer cells RM9 were transfected with murine prostaglandin D(2) synthase (mPGDS) gene by using defective retrovirus vector, designated as RM9-mPGDS. In addition, RM9 was also transfected with only defective retrovirus vector, designated as RM9-EV and used as control in this study. The expression and production of the gene were confirmed by RT-PCR and ELISA, respectively. For in vivo study, RM9-mPGDS was injected into the back of C57BL/6 mice, then resulted tumor was used for pathological analysis 14days after the inoculation. Tumor cell apoptosis in the tissue was detected by TUNEL staining. Retrovirally transfected mPGDS in RM9 significantly induced apoptosis in vivo but not in vitro, by TUNEL staining and cell death ELISA, respectively. Our results strongly suggested that the apoptosis induced in RM9-mPGDS in vivo was probably achieved in tumor environment such as hypoxic condition. The introduction of PGDS gene into cancer cells might be a novel therapy against cancer., (Crown Copyright © 2012. Published by Elsevier SAS. All rights reserved.)

Endometriosis is one of the most common gynecological diseases in women of reproductive age. Although cyclooxygenase (COX)-2 inhibitors are effective in the treatment of endometriosis, the adverse cardiovascular effects associated with these inhibitors have limited their use. Microsomal prostaglandin E synthase-1 (mPGES-1) is an inducible enzyme downstream of COX-2 in prostaglandin E(2) biosynthesis. Previously, we developed mPGES-1 knockout mice (mPGES-1(-/-)) and have identified for the first time the roles of ectopic lesion- and host-associated mPGES-1 in angiogenesis and the growth of endometrial tissues. When mPGES-1(-/-) endometrial fragments were implanted into wild type (WT) mice (mPGES-1(-/-)→WT), or WT fragments implanted into mPGES-1(-/-) mice (WT→mPGES-1(-/-)), the growth of the implants was suppressed at days 14 and 28 after implantation, compared toWT→WT transplantation. An even greater degree of suppression was observed in mPGES-1(-/-) endometrial fragments implanted into mPGES-1(-/-) mice (mPGES-1(-/-)→mPGES-1(-/-)). After WT-WT implantation, mPGES-1 expression was localized at the border of the implanted endometrial tissues. Microvessel density, determined by CD31 immunostaining, was markedly suppressed in the mPGES-1(-/-) endometrial fragments implanted into mPGES-1(-/-) mice, with some suppression also observed in the mPGES-1(-/-)→WT and WT→mPGES-1(-/-) groups. The expression of vascular endothelial growth factor (VEGF-A) was significantly reduced in mPGES-1(-/-) endometrial tissues implanted into mPGES-1(-/-) mice at days 14 and 28, in comparison to the WT→WT group. These results suggested that mPGES-1 enhanced angiogenesis and growth of the endometrial implant, and indicate that mPGES-1 may be a good therapeutic target for endometriosis., (Copyright © 2010. Published by Elsevier SAS.)

Microsomal prostaglandin (PG) E synthase 1 (mPGES-1) is a major PGE synthase and has recently been reported to be expressed at high levels in several cancer types. We previously reported that the PGE receptor EP3 is expressed in bone marrow (BM) derived cells, enriched in stromal tissue, and enhances the potential for tumor angiogenesis. In the present study, we examined the role of mPGES-1-expressing BM cells on tumor angiogenesis using BM chimeric mice. After lethal radiation, wild-type (WT) BMs were excised and replaced with BM cells isolated from mPGES-1 knockout mice (mPGES-1(-/-)). Lewis lung carcinoma cell were implanted subcutaneously and the levels of neoangiogenesis were measured tumor growth in mPGES-1(-/-) BM chimeric mice was significantly reduced compared to that observed in WT BM chimeric mice. Tumor-associated angiogenesis as measured by histological analysis was localized to tumor stroma, and was significantly lower in mPGES-1(-/-) BM chimeric mice compared to that in WT BM chimeric mice. Tumor sections probed by immunohistochemistry revealed that vascular endothelial growth factor (VEGF) that was present in the stromal tissue was markedly reduced in mPGES-1(-/-) BM chimeric mice compared to WT BM chimeras. These results suggest that the recruitment of mPGES-1-expressing BM cells to tumor-associated stromal tissue is crucial for tumor growth and angiogenesis, and correlates with gene expression of host VEGF in stroma. Taken together, these data suggest that regulation of mPGES-1-expressing BM cell recruitment to the site of primary tumors may be a novel strategy for the treatment of solid tumors., (Copyright 2010. Published by Elsevier SAS.)

Prostaglandin E(2) (PGE(2)) and prostaglandin E (EP) receptor signaling pathways have been implicated in the promotion of tumor growth and angiogenesis. However, little is known about their roles in lymphangiogenesis during tumor development. The present study evaluates whether endogenous PGE(2) exhibits a critical role in tumor-associated lymphangiogenesis. Treatment of male C57BL/6 mice with a cyclooxygenase-2 inhibitor, celecoxib, for seven days resulted in a 52.4% reduction in tumor size induced by subcutaneous injection of murine Lewis lung cells. Celecoxib treatment down-regulated the expression of vascular endothelial growth factor receptor (VEGFR)-3 in stromal tissues by 73.9%, and attenuated expression of podoplanin, a marker for lymphatic endothelial cells. To examine the role of host PGE receptor signaling, we tested four kinds of EP receptor knockout mice. At Day 7 after tumor cell implantation, EP3 receptor knockout mice, but not EP receptor knockout mice lacking EP1, EP2, or EP4, exhibited a 53.3% reduction in tumor weight, which was associated with a 74.5% reduction in VEGFR-3 mRNA expression in tumor stromal tissues. At Day 14, VEGFR-3 expression in EP3-/- mice remained significantly lower than that of their wild-type (WT) counterparts. The expression of VEGF-C in the tumor stromal tissues in EP3-/- mice were also reduced by 22.1% (Day 7) and 44.1% (Day 14), respectively. In addition, the level of immunoreactive podoplanin in the tumor tissues from EP3-/- mice was less than that of WT. These results suggest that host EP3 receptor signaling regulates tumor-associated lymphangiogenesis by up-regulating expression of VEGF-C and its receptor, VEGFR-3, in tumor stromal tissues. Host EP3 blockade together with COX-2 inhibition may be a novel therapeutic strategy to suppress tumor-associated lymphangiogenesis., (2009 Elsevier Masson SAS. All rights reserved.)

Chronic inflammation, which is characterized by the proliferation of granulation tissues, is known to be regulated by angiogenesis. Recent results suggest that bone marrow-derived (BM-derived) hematopoietic cells regulate angiogenesis in vivo. We previously reported that the angiogenesis occurring during chronic inflammation is enhanced in response to the endogenous prostaglandins (PGs) derived from an inducible cyclooxygenase-2 (COX-2). In the present study, we examined the role of BM-derived cells expressing an E-type PG receptor subtype, EP3, in sponge-induced angiogenesis. The replacement of wild-type (WT) BM with BM cells (BMCs) from green fluorescent protein (GFP) transgenic mice revealed that the formation of granulation tissue around the sponge implants developed via the recruitment of BMCs. This recruitment was enhanced by topical injections of vascular endothelial growth factor (VEGF)-A, and a VEGF-dependent increase in the recruitment of BMCs was inhibited by a COX-2 inhibitor, celecoxib. FACS analysis of the granulation tissues after treatment with collagenase revealed that the Mac-1-positive macrophage fraction was enhanced by topical injections of VEGF-A, and that this increased recruitment of Mac-1-positive BMCs was inhibited by celecoxib. Selective knockdown of EP3 performed by BM transplantation with BMCs isolated from EP3 knockout (EP3) mice reduced sponge-induced angiogenesis, as estimated by mean vascular number and CD31 expression in the granulation tissues. This reduction in angiogenesis in EP3(-/-) BM chimeric mice was accompanied by reductions in the recruitment of BMCs, especially of Mac-1-positive cells and Gr-1-positive cells. These results indicate that the recruited bone marrow cells that express the EP3 receptor have a significant role in enhancing angiogenesis during chronic proliferative inflammation., (2009 Elsevier Masson SAS. All rights reserved.)

Angiotensin II (Ang II) is a bioactive peptide that plays important roles in blood pressure regulation and salt-water homeostasis. Recently, Ang II was reported to function in the promotion of angiogenesis. Since the wound healing process is highly dependent upon angiogenesis, we employed Ang II receptor knockout mice (AT1a(-/-)) to investigate whether or not Ang II facilitates angiogenesis and wound healing via AT1a receptor signaling. In comparison to wild-type (WT) mice, wound healing and wound-induced angiogenesis were significantly suppressed in AT1a(-/-) mice, and these mice exhibited reduced expression of CD31 in wound granulation tissues. In comparison to vehicle-treated mice, wound healing was delayed significantly in mice treated with an AT1-R antagonist and this delay was accompanied by the reduced expression of vascular endothelial growth factor in wound granulation tissues. These findings suggest that Ang II-AT1a signaling plays a crucial role in wound healing and wound-induced angiogenesis.

Objective: Angiogenesis, the formation of new capillary blood vessels, is essential for tumor progression. We had reported that Type 1 angiotensin receptor (AT1-R) antagonist reduced tumor-associated angiogenesis. Since antiangiogenic agents were reported to enhance efficacy of radiation therapy, we tested here whether or not AT1-R blockade facilitates the effects of radiation., Methods: 1 x 10(6) LLC cells were injected into the subcutaneous tissue of male C57BL/6 mice, and when the average tumor volume reached around 0.1 cm(3), radiation doses (3, 5, 10, and 15 Gy) were given on day 1., Results: The mean tumor volumes at day 22 were 6.39 (3 Gy), 6.15 (5 Gy), 5.15 (10 Gy), and 3.07 (15 Gy) cm(3), respectively. Combination of 10 Gy radiation with AT1R antagonist TCV-116 (30 mg/kg) significantly inhibited tumor growth by 83% (1.47 +/- 0.11 cm(3), P < 0.01) in comparison with its inhibition of control tumors (8.81 +/- 0.45 cm(3)). The same was true for mean vessel density, and the combination therapy markedly reduced tumor-associated angiogenesis. This was confirmed by the reduced expression of CD31. LLC tumor growth was blocked by neutralizing antibody against vascular endothelial growth factor (VEGF). Real-time PCR analysis of VEGF disclosed a marked reduction in the mice under combination therapy, compared with control mice., Conclusions: These results suggest that combination of radiation with AT1-R blockade markedly reduced the LLC growth rate, and that this was due to reduction of neovascularization by reducing VEGF levels. Combination therapy consisting of radiation and AT1R blockade may become an effective novel strategy for cancer treatment.

Calcitonin gene-related peptide (CGRP) is a 37-amino acid neuropeptide produced by tissue-specific alternative splicing of the primary transcript of the calcitonin/CGRP gene. CGRP is widely distributed in the central and peripheral neuronal systems and exhibits numerous biological activities in mammals. We examined in the present study whether or not endogenous CGRP released from neuronal systems facilitates neovascularization indispensable to wound healing. In CGRP knockout mice (CGRP-/-), wound-induced angiogenesis and wound closure were significantly suppressed compared with those in wild-type mice. The suppressed healing in CGRP-/- was accompanied by reduction in expressions of vascular endothelial growth factor (VEGF) in the wound granulation tissues. A CGRP antagonist, CGRP8-37 when infused with mini-osmotic pumps subcutaneously blocked the wound healing processes and reduced the expressions of CD31 and VEGF expression in the wound granulation tissues. Wound healing process was significantly delayed in neuropeptide-depleted mice pretreated with capsaicin, compared with vehicle-treated mice. These results indicate that CGRP derived from neuronal systems may facilitate wound healing and angiogenesis. Targeting of CGRP may be promising in controlling angiogenesis related to pathophysiological conditions.

Expression of receptors for prostaglandin (PG) and leukotriene (LT) has been reported to detect in endometrium and smooth muscle of uterus, suggesting involvement of these arachidonic metabolites in endometrial pathology and reproductive biology. Lipoxin (LX), which is produced by lipoxygenases from arachidonic acid, has been characterized as an anti-inflammatory lipid mediator. Biological actions of Lipoxin A4 (LXA4) are mediated through the specific receptor. In order to know roles of LXA4 in female genitalia, expression of LXA4 receptor mRNA was quantified by real-time polymerase chain reaction. Significantly higher expression of the receptor was detected in endometrium and myometrium than ovary in normal rats. Expression of the receptor in endometrium was increased at stage of proestrus cycle under physiological condition. Exogenous administration of progesterone into female rats significantly reduced the expression, while administration of estradiol or pregnant mare serum gonadotropin (PMSG) did not. Both, endometrium in experimental endometriosis induced in rats and the tissues from patients with ectopic endometriosis showed a higher expression of LXA4 receptor compared to the normal tissues. In contrast, expressions of BLT1 and BLT2, receptors for leukotriene B4, did not change in the endometriosis. These observations suggest a possible role of LXA4 and the receptor under physiological estrus cycle and pathological condition as endometriosis.