Modulation of lymphangiogenesis: a new target for aspirin and other nonsteroidal anti-inflammatory agents? A systematic review

Aspirin Mediates Its Antitumoral Effect Through Inhibiting PTTG1 in Pituitary Adenoma

CONTEXT

DNA demethylation and inhibitory effects of aspirin on pituitary cell proliferation have been demonstrated.

OBJECTIVE

Our aim was to clarify the molecular mechanisms behind the aspirin-related effects in pituitary cells.

METHODS

DNA methylome and whole transcriptome profile were investigated in RC-4B/C and GH3 pituitary cell lines upon aspirin treatment. Effects of aspirin and a demethylation agent, decitabine, were further tested in vitro. PTTG1 expression in 41 human PitNET samples and whole genome gene and protein expression data of 76 PitNET and 34 control samples (available in Gene Expression Omnibus) were evaluated.

RESULTS

Aspirin induced global DNA demethylation and consequential transcriptome changes. Overexpression of Tet enzymes and their cofactor Uhrf2 were identified behind the increase of 5-hydroxymethylcytosine (5hmC). Besides cell cycle, proliferation, and migration effects that were validated by functional experiments, aspirin increased Tp53 activity through p53 acetylation and decreased E2f1 activity. Among the p53 controlled genes, Pttg1 and its interacting partners were downregulated upon aspirin treatment by inhibiting Pttg1 promoter activity. 5hmC positively correlated with Tet1-3 and Tp53 expression, and negatively correlated with Pttg1 expression, which was reinforced by the effect of decitabine. Additionally, high overlap (20.15%) was found between aspirin-regulated genes and dysregulated genes in PitNET tissue samples.

CONCLUSION

A novel regulatory network has been revealed, in which aspirin regulated global demethylation, Tp53 activity, and Pttg1 expression along with decreased cell proliferation and migration. 5hmC, a novel tissue biomarker in PitNET, indicated aspirin antitumoral effect in vitro as well. Our findings suggest the potential beneficial effect of aspirin in PitNET.

Epigenetic Changes in Asthma: Role of DNA CpG Methylation

For the past three decades, more than a thousand of genetic studies have been performed to find out the genetic variants responsible for the risk of asthma. Until now, all of the discovered single nucleotide polymorphisms have explained genetic effects less than initially expected. Thus, clarification of environmental factors has been brought up to overcome the 'missing' heritability. The most exciting solution is epigenesis because it intervenes at the junction between the genome and the environment. Epigenesis is an alteration of genetic expression without changes of DNA sequence caused by environmental factors such as nutrients, allergens, cigarette smoke, air pollutants, use of drugs and infectious agents during pre- and post-natal periods and even in adulthood. Three major forms of epigenesis are composed of DNA methylation, histone modifications, and specific microRNA. Recently, several studies have been published on epigenesis in asthma and allergy as a powerful tool for research of genetic heritability in asthma albeit epigenetic changes are at the starting point to obtain the data on specific phenotypes of asthma. In this presentation, we mainly review the potential role of DNA CpG methylation in the risk of asthma and its sub-phenotypes including nonsteroidal anti-inflammatory exacerbated respiratory diseases.

Aspirin targets P4HA2 through inhibiting NF-κB and LMCD1-AS1/let-7g to inhibit tumour growth and collagen deposition in hepatocellular carcinoma

Background

Abnormal construction of the extracellular matrix (ECM) is intimately linked with carcinogenesis and the development of solid tumours, especially hepatocellular carcinoma (HCC). As the major component of the ECM, collagen plays a pivotal role in carcinogenesis. P4HA2, the essential enzyme during collagen formation, becomes an important target in HCC treatment. Here, we tried to decipher whether aspirin (ASA), a classic anti-inflammatory drug, could improve the prognosis of HCC through targeting P4HA2.

Methods

Western blotting, qRT-PCR assay, immunofluorescence staining, luciferase reporter gene assay, and ChIP assay were applied to demonstrate the molecular mechanism of the regulation of P4HA2 expression by aspirin. A mouse xenograft model, cell viability assay, colony formation assay, and immunohistochemistry analysis were used to evaluate the anti-fibrosis effect of aspirin through targeting the NF-κB/P4HA2 axis and LMCD1-AS1/let-7g/P4HA2 axis in vitro and in vivo. The TCGA database was used to evaluate the correlation among P4HA2, let-7g, LMCD1-AS1 and overall survival of HCC patients.

Findings

In xenograft mice, aspirin was capable of targeting P4HA2 to decrease collagen deposition, resulting in the inhibition of liver tumour growth. TCGA database analysis revealed the close association between a higher P4HA2 concentration in HCC patients and shorter overall survival or a higher cancer stage and the pathological grade. Mechanistically, NF-κB can bind to the promoter of P4HA2 to activate its transcription. Moreover, lncRNA LMCD1-AS1 functions as a molecular sponge of let-7g to post-transcriptionally induce the target gene of let-7g, namely, P4HA2.

Interpretation

Our findings disclose the novel role and regulatory mechanism of aspirin in the suppression of HCC by disrupting abnormal collagen deposition.

Funds

973 Program, National Natural Scientific Foundation of China, Fundamental Research Funds for the Central Universities, Project of Prevention and Control of Key Chronic Non-Infectious Diseases.

Aspirin ameliorates lung cancer by targeting the miR-98/WNT1 axis

Background

Aspirin, an anti‐inflammatory drug, has been widely investigated in the treatment of many cancer types, including colorectal, ovarian, breast, and prostate cancers. MicroRNAs (miRNAs) are the most well studied noncoding RNAs in cancers. In the current study, we were interested in defining the function of aspirin in lung cancer treatment and the related noncoding RNAs involved in this process.

Methods

The function of aspirin in lung cancer growth was evaluated by cell viability and colony formation assays. Screening of miRNAs affected by aspirin was performed through quantitative real‐time PCR. Prediction of miR‐98 targeting WNT1 was performed using online bioinformatics software and was further confirmed by luciferase reporter gene analysis. The levels of miR‐98 and WNT1 were tested through immunoblotting and quantitative real‐time PCR analysis in lung cancer cells under aspirin treatment.

Results

Cell viability was sharply suppressed in lung cancer cells with an increasing dose of aspirin. Aspirin markedly weakened the malignant colony formation ability of lung cancer cells. One out of six tumor suppressor miRNAs could be obviously regulated by aspirin in lung cancer cells. The inhibition of miR‐98 on the luciferase activities of wild‐type 3' untranslated region vectors of WNT1 was clearly revealed in lung cancer cells. Meanwhile, the inhibitor of miR‐98 increased the luciferase activities of wild‐type 3' untranslated region vectors of WNT1. After treatment with aspirin the expression of miR‐98 was induced and then its target gene, WNT1, was depressed in the cells.

Conclusion

Aspirin targets the miR‐98/WNT1 axis to ameliorate lung cancer development.

Complementary Participation of Genetics and Epigenetics in Development of NSAID-exacerbated Respiratory Disease

Nonsteroidal anti-inflammatory drug (NSAID)-exacerbated respiratory disease (NERD) has attracted a great deal of attention because of its association with severe asthma. However, it remains widely underdiagnosed in asthmatics as well as the general population. Upon pharmacological inhibition of cyclooxygenase 1 by NSAIDs, production of anti-inflammatory prostaglandin E2 and lipoxins ceases, while release of proinflammatory cysteinyl leukotrienes increases. To determine the underlying mechanisms, many studies have attempted to elucidate the genetic variants, such as single nucleotide polymorphisms, responsible for alterations of prostaglandins and leukotrienes, but the results of these genetic studies could not explain the whole genetic pathogenesis of NERD. Accordingly, the field of epigenetics has been introduced as an additional contributor to genomic alteration underlying the development of NERD. Recently, changes in CpG methylation, as one of the epigenetic components, have been identified in target tissues of NERD. This review discusses in silico analyses of both genetic and epigenetic components to gain a better understanding of their complementary roles in the development of NERD. Although the molecular mechanisms underlying NERD pathogenesis remain poorly understood, genetic and epigenetic variations play significant roles. Our results enhance the understanding of the genetic and epigenetic mechanisms involved in the development of NERD and suggest new approaches toward better diagnosis and management.

Aspirin suppresses components of lymphangiogenesis and lymphatic vessel remodeling by inhibiting the NF-κB/VCAM-1 pathway in human lymphatic endothelial cells

Lymphangiogenesis is the process of new vessel formation from pre-existing lymphatic vessels. The process mainly involves cell adhesion, migration, and tubule formation of lymphatic endothelial cells. Tumor-induced lymphangiogenesis is an important factor contributing to promotion of tumor growth and cancer metastasis via the lymphatic system. Finding the non-toxic agents that can prevent or inhibit lymphangiogenesis may lead to blocking of lymphatic metastasis. Recently, aspirin, a non-steroidal anti-inflammatory drug (NSAID), has been reported to inhibit in vivo lymphangiogenesis in tumor and incision wound models, but the mechanisms of actions of aspirin on anti-lymphangiogenesis have been less explored. In this study, we aim to explore the mechanism underlying the anti-lymphangiogenic effects of aspirin in primary human dermal lymphatic microvascular endothelial (HMVEC-dLy) cells in vitro. Pretreatment of aspirin at non-toxic dose 0.3 mM significantly suppressed in vitro cord formation, adhesion, and the migration abilities of the HMVEC-dLy cells. Western blotting analysis indicated that aspirin decreased expression of vascular cell adhesion molecule-1 (VCAM-1), at both protein and mRNA levels, and these correlated with the reduction of NF-κB p65 phosphorylation. By using NF-κB inhibitor (BAY-11-7085) and VCAM-1 siRNA, we showed that VCAM-1 expression is downstream of NF-κB activation, and this NF-κB/VCAM-1 signaling pathway controls cord formation, adhesion, and the migration abilities of the HMVEC-dLy cells. In summary, we demonstrate the potential of aspirin as an anti-lymphangiogenic agent, and elucidate its mechanism of action.

Tumor lymphangiogenesis and new drug development

Traditionally, tumor-associated lymphatic vessels have been regarded as passive by-standers, serving simply as a drainage system for interstitial fluid generated within the tumor. However, with growing evidence that tumors actively induce lymphangiogenesis, and that the number of lymphatic vessels closely correlates with metastasis and clinical outcome in various types of cancer, this picture has changed dramatically in recent years. Tumor-associated lymphatic vessels have now emerged as a valid therapeutic target to control metastatic disease, and the first specific anti-lymphangiogenic drugs have recently entered clinical testing. Furthermore, we are just beginning to understand the whole functional spectrum of tumor-associated lymphatic vessels, which not only concerns transport of fluid and metastatic cells, but also includes the regulation of cancer stemness and specific inhibition of immune responses, opening new venues for therapeutic applications. Therefore, we predict that specific targeting of lymphatic vessels and their function will become an important tool for future cancer treatment.

Interaction of Salicylates and the Other Nonsteroidal Anti-Inflammatory Agents With Breast Cancer Endocrine Treatment: Systematic Review

Despite advances in breast cancer treatment, mortality from breast cancer is still high. Undoubtedly, novel treatment strategies are needed for chemoprevention of high-risk women and for the treatment of receptor-negative breast cancer. An appealing strategy would be the combination of breast endocrine treatment with salicylates and the other nonsteroidal anti-inflammatory agents (NSAIDs). This systematic review aimed to synthesize evidence on the possible synergistic antitumor effect of breast cancer endocrine treatment with salicylates and the other NSAIDs. Electronic databases were searched with the appropriate search terms. Most of the identified studies investigated the possible synergistic effect of exemestane with celecoxib in different clinical settings including metastatic treatment, adjuvant treatment, ductal carcinoma in situ. The possible synergistic effect of tamoxifen with celecoxib was investigated in one experimental study and the possible synergistic effect of exemestane with aspirin was investigated in another experimental study. Synergistic effect was detected in the majority of the studies. In conclusion, existing limited evidence suggests synergistic interaction of salicylates and the other NSAIDs in the treatment of estrogen responsive breast cancer with clinical implications in the reversal of acquired resistance to breast cancer endocrine treatment and in chemoprophylaxis.

Lymphangiogenesis and Inflammation-Looking for the "Missing Pieces" of the Puzzle

Several papers about lymphangiogenesis and inflammation focused on the detailed and complicated descriptions of the molecular pathways accompanying both non-tumor and tumor inflammatory-induced lymphatic vessel development. Many authors are tempted to present inflammatory-induced lymphangiogenesis in pathologic conditions neglecting the role of inflammatory cells during embryonic lymphatic vessel development. Some of the inflammatory cells are largely characterized in inflammatory-induced lymphangiogenesis, while others as mast cells, eosinophils, or plasma cells are less studied. No phenotypic characterization of inflammation-activated lymphatic endothelial cell is available in this moment. Another paradox is related to the existence of few papers regarding lymphangiogenesis inside lymphoid organs and for their related pathology. There are still several "missing pieces of such a big puzzle" of lymphangiogenesis and inflammation, with a direct impact on the ineffectiveness of the anti-inflammatory therapy as lymphangiogenesis inhibitors. The present paper will focus on the controversial issues of lymphangiogenesis and inflammation.

The CXCL7/CXCR1/2 axis is a key driver in the growth of clear cell renal cell carcinoma

Mutations in the von Hippel-Lindau gene upregulate expression of the central angiogenic factor VEGF, which drives abnormal angiogenesis in clear cell renal cell carcinomas (ccRCC). However, the overexpression of VEGF in these tumors was not found to correlate with overall survival. Here, we show that the proangiogenic, proinflammatory cytokine CXCL7 is an independent prognostic factor for overall survival in this setting. CXCL7 antibodies strongly reduced the growth of ccRCC tumors in nude mice. Conversely, conditional overexpression of CXCL7 accelerated ccRCC development. CXCL7 promoted cell proliferation in vivo and in vitro, in which expression of CXCL7 was induced by the central proinflammatory cytokine interleukin (IL)-1β. ccRCC cells normally secrete low amounts of CXCL7; it was more highly expressed in tumors due to high levels of IL-1β there. We found that a pharmacological inhibitor of the CXCL7 receptors CXCR1 and CXCR2 (SB225002) was sufficient to inhibit endothelial cell proliferation and ccRCC growth. Because CXCR1 and CXCR2 are present on both endothelial and ccRCC cells, their inhibition affected both the tumor vasculature and the proliferation of tumor cells. Our results highlight the CXCL7/CXCR1/CXCR2 axis as a pertinent target for the treatment of ccRCC.