Ercolano, Giuseppe (2018) Eicosanoids and cancer: Focus on melanoma. [Tesi di dottorato]


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Item Type: Tesi di dottorato
Resource language: English
Title: Eicosanoids and cancer: Focus on melanoma
Date: 10 December 2018
Number of Pages: 145
Institution: Università degli Studi di Napoli Federico II
Department: Farmacia
Dottorato: Scienza del farmaco
Ciclo di dottorato: 31
Coordinatore del Corso di dottorato:
Date: 10 December 2018
Number of Pages: 145
Keywords: Cancer,Melanoma,Cyclooxygenase
Settori scientifico-disciplinari del MIUR: Area 05 - Scienze biologiche > BIO/14 - Farmacologia
Date Deposited: 19 Dec 2018 11:13
Last Modified: 23 Jun 2020 10:03

Collection description

Inflammation plays a key role in tumor promotion and development. Indeed, high levels of cyclooxygenase-2 (COX-2) expression are associated with worse prognosis in several types of cancer including melanoma. The aim of our project, divided in three sections, has been to investigate on the role of COX-2 in melanoma development and progression. In the first phase of the project, we evaluated the expression of both COX-1 and COX-2 in a large panel of human melanoma cells and assessed the effect of COX-2 ablation on cancer cell proliferation and invasiveness by the mean of siRNA technology and by selective inhibition of COX-2 activity. Translation of in vitro data to in vivo models of cutaneous melanoma showed that in COX-2-/- mice tumor development was almost blunted as compared to littermate control C57Bl/6J. Finally, we performed a retrospective clinical study on 45 human lymph node melanoma metastases and correlated COX-2 expression to progression free survival (PFS). Our results show an inverse correlation between PFS and COX-2 expression suggesting that COX-2 is a negative prognostic factor in metastatic melanoma. In addition to COX enzymes, also hydrogen sulfide (H2S), an endogenous gasotransmitter, has been recently demonstrated to be involved in human melanoma. Thus, the second phase of the project was focused on the evaluation of the efficacy of a new H2S-releasing nonsteroidal anti-inflammatory drugs (H2S-NSAIDs) named ATB-346, developed by combining naproxen with a chemical moiety that donates hydrogen sulfide. In particular, we used cell culture and a murine melanoma model to evaluate the effect of ATB-346 on: i) proliferation of human melanoma cells; ii) melanoma development in mice. Cell culture studies demonstrated that ATB-346 reduced the proliferation of human melanoma cells and this effect was associated to induction of apoptosis and inhibition of NF-κB activation. Moreover in vivo data showed that ATB-346 significantly reduced melanoma development. In conclusion, by using this dual approach we propose that COXs and H2S pathway could be innovative therapeutic targets to generate new treatment options based on “combination therapy” for melanoma. Finally, in the third and last phase of the project, we decided to better define the role of COX-2 in melanoma development. The aim was to establish if this enzyme acts predominantly in the microenvironment rather than in tumor cells. For this purpose we deleted COX-2 in B16/F10 murine melanoma cells by the mean of CRISPR/Cas9 technology. We firstly investigated on the effect of COX-2 knockdown on proliferation, migration, invasion and colonie formation of B16/F10 murine melanoma cells. In vitro studies demonstrated that CRISPR/Cas9-mediated COX-2 knockdown decreased proliferation of B16/F10 cells and inhibited some features of metastatic melanoma such as motility, invasiveness and focus formation. Finally, subcutaneously injection of B16/F10 cells knocked down for COX-2 showed slightly reduced melanoma growth and reduced the CXCL1 chemokine plasma levels. In addition, we also investigated on the expression and role of miR-143-3p in human malignant melanoma that has been shown to be dysregulated in many cancers. Our results showed that the expression of miR-143-3p was lower in human melanoma cells, as well as human tumor biopsy specimens, when compared to normal human melanocytes. Ectopic expression of miR-143-3p in human melanoma cells inhibited proliferation, migration, invasion and promoted apoptosis acting through a molecular mechanism that, at least in part, is dependent on inhibition of the COX-2 gene. Collectively, our findings show that COX-2 has a critical role in modulating melanoma development and progression. Nonetheless, significant challenges still lie ahead for blocking the interactions between the microenvironment and tumors.


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