Upregulation of Prostaglandin E2 by Inducible Microsomal Prostaglandin E Synthase-1 in Colon Cancer

Furazanopyrazine-based novel promising anticancer agents interfering with the eicosanoid biosynthesis pathways by dual mPGES-1 and sEH inhibition

We report the identification of a new set of compounds based on the furazanopyrazine core interfering with eicosanoid biosynthesis and acting as potentially effective anti-inflammatory and anticancer agents. Based on our previous promising results on a set of furazanopyrazine-based compounds against the microsomal prostaglandin E2 synthase-1 (mPGES-1) enzyme, we here identified derivatives with improved pharmacokinetic properties by replacing the ester moiety with a more stable ether group. A focused virtual library of 1 × 104 molecules was built and screened against mPGES-1 through molecular docking experiments, leading to the selection of 10 candidates for synthesis and biological evaluation. Several molecules were found to inhibit mPGES-1 and, among them, two items featured IC50 values in the low micromolar range. Additional computational studies on the collection of synthesized compounds demonstrated that compound 3b, previously emerged as an mPGES-1 inhibitor, interfered with soluble epoxide hydrolase (sEH) activity, thus emerging as a valuable dual mPGES-1/sEH inhibitor. The pharmacokinetic features of the most potent compounds were accurately estimated. Unfortunately, poor outcomes were obtained for 3b; on the other hand, compound 7e exhibited promising mPGES-1 inhibition and excellent pharmacokinetic profile, demonstrating that the novel furazanopyrazine-based items with ether moiety possess improved pharmacokinetic properties compared to the ester-based compounds reported in our previous study. Additionally, the anticancer properties of 7e and 7d, the latter emerged as the most active mPGES-1 inhibitor, were evaluated and both compounds showed promising activities against HCT-116 human colorectal cancer (CRC) cells. These findings highlight the furazanopyrazine core as a promising scaffold for disclosing new anti-inflammatory drugs with the ability to inhibit targets belonging to arachidonic acid cascade.

5-methyl-2-carboxamidepyrrole-based novel dual mPGES-1/sEH inhibitors as promising anticancer candidates

Inhibiting microsomal prostaglandin E2 synthase-1 (mPGES-1), an inducible enzyme involved in prostaglandin E2 (PGE2) biosynthesis and tumor microenvironment (TME) homeostasis, is a valuable strategy for treating inflammation and cancer. In this work, 5-methylcarboxamidepyrrole-based molecules were designed and synthesized as new compounds targeting mPGES-1. Remarkably, compounds 1f, 2b, 2c, and 2d were able to significantly reduce the activity of the isolated enzyme, showing IC50 values in the low micromolar range. With the aim of further profiling the synthesized molecules, their ability to interfere with the activity of soluble epoxide hydrolase (sEH), whose inhibition blocks the loss of the anti-inflammatory mediators epoxyeicosatrienoic acids (EETs or epoxyicosatrienoic acids), was investigated in silico and by employing specific biological assays. Among the set of tested compounds, 1f, 2b, 2c, and 2d emerged as mPGES-1/sEH dual inhibitors. Moreover, given that overexpression of mPGES-1 has been observed in many human tumors, we finally explored the biological effect of our compounds in an in vitro model of human colorectal cancer (CRC). The obtained outcomes pave the way for future investigation to optimize and further characterize anticancer pharmacological profile of the carboxamidepyrrole-based molecules.

Prostaglandin E2 in the Tumor Microenvironment, a Convoluted Affair Mediated by EP Receptors 2 and 4

The involvement of the prostaglandin E2 (PGE2) system in cancer progression has long been recognized. PGE2 functions as an autocrine and paracrine signaling molecule with pleiotropic effects in the human body. High levels of intratumoral PGE2 and overexpression of the key metabolic enzymes of PGE2 have been observed and suggested to contribute to tumor progression. This has been claimed for different types of solid tumors, including, but not limited to, lung, breast, and colon cancer. PGE2 has direct effects on tumor cells and angiogenesis that are known to promote tumor development. However, one of the main mechanisms behind PGE2 driving cancerogenesis is currently thought to be anchored in suppressed antitumor immunity, thus providing possible therapeutic targets to be used in cancer immunotherapies. EP2 and EP4, two receptors for PGE2, are emerging as being the most relevant for this purpose. This review aims to summarize the known roles of PGE2 in the immune system and its functions within the tumor microenvironment. SIGNIFICANCE STATEMENT: Prostaglandin E2 (PGE2) has long been known to be a signaling molecule in cancer. Its presence in tumors has been repeatedly associated with disease progression. Elucidation of its effects on immunological components of the tumor microenvironment has highlighted the potential of PGE2 receptor antagonists in cancer treatment, particularly in combination with immune checkpoint inhibitor therapeutics. Adjuvant treatment could increase the response rates and the efficacy of immune-based therapies.

Prostaglandin E2 Exposure Disrupts E-Cadherin/Caveolin-1-Mediated Tumor Suppression to Favor Caveolin-1-Enhanced Migration, Invasion, and Metastasis in Melanoma Models

Caveolin-1 (CAV1) is a membrane-bound protein that suppresses tumor development yet also promotes metastasis. E-cadherin is important in CAV1-dependent tumor suppression and prevents CAV1-enhanced lung metastasis. Here, we used murine B16F10 and human A375 melanoma cells with low levels of endogenous CAV1 and E-cadherin to unravel how co-expression of E-cadherin modulates CAV1 function in vitro and in vivo in WT C57BL/6 or Rag-/- immunodeficient mice and how a pro-inflammatory environment generated by treating cells with prostaglandin E2 (PGE2) alters CAV1 function in the presence of E-cadherin. CAV1 expression augmented migration, invasion, and metastasis of melanoma cells, and these effects were abolished via transient co-expression of E-cadherin. Importantly, exposure of cells to PGE2 reverted the effects of E-cadherin expression and increased CAV1 phosphorylation on tyrosine-14 and metastasis. Moreover, PGE2 administration blocked the ability of the CAV1/E-cadherin complex to prevent tumor formation. Therefore, our results support the notion that PGE2 can override the tumor suppressor potential of the E-cadherin/CAV1 complex and that CAV1 released from the complex is phosphorylated on tyrosine-14 and promotes migration/invasion/metastasis. These observations provide direct evidence showing how a pro-inflammatory environment caused here via PGE2 administration can convert a potent tumor suppressor complex into a promoter of malignant cell behavior.

Impact of Postoperative Naples Prognostic Score to Predict Survival in Patients with Stage II-III Colorectal Cancer

BACKGROUND

The Naples prognostic score (NPS) is a scoring system that reflects a patient's systemic inflammatory and nutritional status. This study aimed to evaluate whether postoperative NPS is effective in assessing the prognosis of stage II-III colorectal cancer (CRC) patients compared with preoperative NPS.

METHODS

Between 2005 and 2012, a total of 164 patients diagnosed with stage II-III CRC, who underwent curative resection followed by adjuvant chemotherapy, were divided into two groups: Group 0-1 (NPS = 0-2) and Group 2 (NPS = 3 or 4). Preoperative NPS was calculated based on the results before surgeries, and postoperative NPS was assessed using the results obtained before adjuvant chemotherapy.

RESULTS

The overall survival of Group 0-1 was higher than that of Group 2 in both pre- and postoperative NPS assessments. According to the ROC curve analysis, the Area Under the Curve (AUC) ratio for postoperative NPS was 0.64, compared with 0.57 for preoperative NPS, 0.52 for the preoperative neutrophil-lymphocyte ratio (p = 0.032), and 0.51 for the preoperative platelet-lymphocyte ratio (p = 0.027).

CONCLUSIONS

Postoperative NPS is effective in predicting the prognosis of stage II-III CRC patients who underwent curative resection followed by adjuvant chemotherapy. The use of NPS could be beneficial in evaluating the prognosis of CRC patients after surgeries.

The calcium-sensing receptor modulates the prostaglandin E2 pathway in intestinal inflammation

Introduction: The prostaglandin E2 (PGE2) pathway is one of the main mediators of intestinal inflammation. As activation of the calcium-sensing receptor (CaSR) induces expression of inflammatory markers in the colon, we assessed the impact of the CaSR on the PGE2 pathway regulation in colon cancer cells and the colon in vitro and in vivo. Methods and Results: We treated CaSR-transfected HT29 and Caco-2 colon cancer cell lines with different orthosteric ligands or modulators of the CaSR and measured gene expression and PGE2 levels. In CaSR-transfected HT29CaSR-GFP and Caco-2CaSR-GFP cells, the orthosteric CaSR ligand spermine and the positive allosteric CaSR modulator NPS R-568 both induced an inflammatory state as measured by IL-8 gene expression and significantly increased the expression of the PGE2 pathway key enzymes cyclooxygenase (COX)-2 and/or prostaglandin E2 synthase 1 (PGES-1). Inhibition of the CaSR with the calcilytic NPS 2143 abolished the spermine- and NPS R-568-induced pro-inflammatory response. Interestingly, we observed cell-line specific responses as e.g. PGES-1 expression was affected only in HT29CaSR-GFP but not in Caco-2CaSR-GFP cells. Other genes involved in the PGE2 pathway (COX-1, or the PGE2 receptors) were not responsive to the treatment. None of the studied genes were affected by any CaSR agonist in GFP-only transfected HT29GFP and Caco-2GFP cells, indicating that the observed gene-inducing effects of spermine and R-568 were indeed mediated by the CaSR. In vivo, we had previously determined that treatment with the clinically approved calcimimetic cinacalcet worsened symptoms in a dextran sulfate sodium (DSS)-induced colitis mouse model. In the colons of these mice, cinacalcet significantly induced gene expression of PGES-2 and the EP3 receptor, but not COX-2; while NPS 2143 increased the expression of the PGE2-degrading enzyme 15-hydroxyprostaglandin dehydrogenase (15-PGDH). Importantly, neither treatment had any effect on the colons of non-DSS treated mice. Discussion: Overall, we show that activation of the CaSR induces the PGE2 pathway, albeit with differing effects in vitro and in vivo. This may be due to the different microenvironment in vivo compared to in vitro, specifically the presence of a CaSR-responsive immune system. Since calcilytics inhibit ligand-mediated CaSR signaling, they may be considered for novel therapies against inflammatory bowel disease.