New pharmacological targets for human diseases

INTRODUCTION In the past decade, significant steps have been made in cancer research, particularly in the field of targeted therapy driven by the identification of specific molecular alterations in various tumours. This continuous evolution of knowledge has led to the discovery of new druggable biomarkers, optimizing therapeutic efficiency while minimizing side effects associated with conventional cancer treatments. Notably, breast cancer is the most prevalent cancer, accounted for 12.5% of new cases in 2020. Lifestyle factors, including alcohol consumption, smoking, and obesity, strongly influence its occurrence. The heterogeneous nature of breast cancer poses challenges, with some cases displaying slow growth and good prognosis, while others prove aggressive and unresponsive to conventional therapies. Advances in targeted therapies, such as endocrine therapies and HER2 inhibitors, showcase promising results and exemplify personalized approaches to breast cancer. However, it is necessary to discover novel molecular targets, aiding clinicians in refining therapeutic decisions. Additionally, human behaviours, particularly obesity resulting from excessive calorie intake, plays a pivotal role in tumours onset, with approximately 20% of tumours attributed to obesity. Increasing evidence suggests specific alterations in lipid metabolism in cancer cells, emphasizing the need to explore these pathways for a deeper understanding of cancer development and outcomes. Lipid metabolism is in a constant state of dynamic equilibrium through food intake, de-novo lipogenesis, and consumption of lipids, to satisfy the needs of the body. Therefore, alterations of one or more of these processes or its dysfunctions, such as in the case of the metabolic syndrome and type 2 diabetes mellitus, can damage the liver as it represents the main organ for lipid metabolism. This thesis is the result of a study carried out for the characterisation of two pharmacological targets and their role in the metabolic pathways respectively in mammarian cancer and non-alcoholic fatty liver disease (NAFLD) leading to liver cancer. I have divided the work in two sections as the activities for the study of each of the molecular target: 1. In the first section I report an already peer-reviewed published work based on the pharmacological inhibition of the DEAD‐box RNA helicase 3 X (DDX3X). Specifically, it focuses on the pharmacological inhibition DDX3X as a potential treatment for breast cancer. Inhibition of DDX3X has demonstrated reduced cell proliferation in various tumour tissues, particularly in breast cancer, where its expression correlates with aggressiveness. The study employed an in-silico drug discovery approach, identifying FHP01 as a promising molecule through molecular docking at DDX3X's RNA binding site. Specifically, FHP01 displayed potent antiproliferative effects against different breast cancer cell types in vitro, notably against triple-negative breast cancer (TNBC) cells. In vivo experiments with MDA MB 231-derived TNBC xenograft models showed a significant reduction in tumour growth. Importantly, FHP01 demonstrated good bioavailability and exhibited no toxicity on normal peripheral blood mononuclear cells in vitro and on several mouse tissues in vivo. The findings suggest that FHP01 and related compounds hold promise as a novel therapeutic approach with potential efficacy against breast cancer, including the challenging triple-negative subtype, where targeted therapies are limited. 2. In the second section I report recent findings on the involvement of mitogen activated protein kinase 15 (MAPK15) in non-alcoholic fatty liver disease (NAFLD). NAFLD stands out as the predominant cause of chronic liver disease globally, encompassing stages from simple steatosis to non-alcoholic steatohepatitis (NASH), which can advance to cirrhosis and hepatocellular carcinoma (HCC), the primary form of liver cancer. Notably, NASH-induced HCC is considered less sensible to cure compared to HCC resulting from viral factors. The excessive accumulation of fatty acids within hepatocytes is identified as a pivotal event in NAFLD progression. Fatty acid transporters play a crucial role in regulating fatty acid uptake across the plasma membrane. The presented data indicate a correlation between the atypical MAP kinase, MAPK15, and hepatic steatosis. Preliminary findings suggest that MAPK15 influences fatty acid transporters in vitro and in vivo. Reduced or absent expression of MAPK15 in mammalian cells is linked to increased lipid accumulation, leading to hepatic steatosis, adipose tissue accumulation, and insulin resistance factors that elevate the risk of cancer development. The data presented underscore the need for further investigation into the involvement of MAPK15 in NAFLD development. Further investigation is now needed in order to understand how MAPK15 is involved in the development of NAFLD and, finally, if its expression may represent a marker of the worsening of liver steatosis, opening new possibilities to prevent NASH and liver cancer development.