/library/oar/handle/123456789/111193 Wed, 24 Dec 2025 13:47:41 GMT 2025-12-24T13:47:41Z /library/oar/handle/123456789/141610 Title: Genetic, behavioural and molecular studies of Gemin3 using drosophila melanogaster Abstract: N/A Description: Ph.D.(Melit.) Sun, 01 Jan 2023 00:00:00 GMT /library/oar/handle/123456789/141610 2023-01-01T00:00:00Z /library/oar/handle/123456789/119689 Title: Analysis of Opuntia ficus-indica triggered cellular mechanisms in the protection against cellular stressor Abstract: The aim of the study was to analyse the ability, effectiveness, and mechanisms of action of the selected plant extract – prickly pear extract (PPE) – from the fruit of a local cultivar of Opuntia ficus-indica provided by and proprietary to Nutribiotech ¸£ÀûÔÚÏßÃâ·Ñ Limited, Malta, as a mode of protection against the cellular damage induced by cellular stressors on human dermal fibroblasts. Specifically, the cellular stressors used were heat stress, oxidative stress and UV irradiation, and these have the potential to exert deleterious effects on the cellular microarchitecture and physiology that may result in pathologies secondary to the effect of these injurious stimuli including but is not limited to, sunburn, cellular aging, and carcinogenesis. A cytoprotective effect was observed on exposure of human dermal fibroblasts to cytotoxic levels of heat stress (44°C for 1 h), menadione induced oxidative stress (25 μM, 12.5 μM and 6.25 μM), UVC (10 µJ/m2) and UVA (5 J/cm2) irradiation by varying degrees instigated by PPE (0.002 %, 0.004 %, 0.01 %, 0.02 %, 0.04 % and 0.08 %) treatment, reaching zenith at PPE (0.04 %) when considering the totality of the results of the Cell Titre Glo / Presto blue viability assay and scratch assay. Mechanistic elucidation was performed by means of transcriptome analysis using RNA sequencing focusing on the effect of PPE (0.04 %) treatment at alleviating the observed deleterious effect of heat stress (44°C for 1 h) and menadione induced oxidative stress (6.25 μM). The results indicate that the Opuntia ficus-indica extract used in this study provided protection against both heat and oxidative stress through the modulation of gene expression primarily related to cell cycle, incorrect/unfolded protein response (UPR), DNA repair and cytokine systems. In heat stress, a TP53 independent downregulation of cell cycle through GADD45G, GADD45A, MDM2 upregulation as well as an increase in cellular response to UPR showed by upregulation of DNAJB9, HSPA5, HSPA1A, HSPA1B. In oxidative stress, upregulated DNA repair and cell cycle pathways characterised by the upregulation of the genes RAD51AP1, ESCO2, POLQ and GINS2 with the concomitant downregulation of pathways related to morphogenesis and differentiation as well as RNA and ribosome processing. The upregulation of SESN2 is further evidence of the antioxidant effects of the PPE. Finally, the downregulation of inflammatory cytokine genes CXCL3, CXCL8, IL33, oxytocin receptor gene OXTR, SOCS cytokine signalling genes as well as the overall downregulation of the JAK-STAT pathway and the genes IL6, JAK3 are also indicative of a protective effect conferred by the PPE against oxidative stress. These findings advance the frontiers of knowledge in plant-based dermatoprotection and possibly open an avenue for the prophylactic application of Opuntia ficus-indica extracts as a defence against the deleterious implications of a plethora of cellular stressors. Description: Ph.D.(Melit.) Sun, 01 Jan 2023 00:00:00 GMT /library/oar/handle/123456789/119689 2023-01-01T00:00:00Z /library/oar/handle/123456789/117444 Title: Investigating the role of the protein methyltransferases EHMT2 and PRMT5 on the epithelial-to-mesenchymal transition of colorectal cancer Abstract: The epithelial-to-mesenchymal transition (EMT) is a process by which cancer cells lose their epithelial characteristics and adopt a mesenchymal morphology. EMT is associated with chemoresistance. Dysregulation in protein methylation is associated with EMT in a number of cancer subtypes. This study investigated the influence of 5-fluorouracil (5-FU) resistance on EMT and protein methylation in colorectal cancer (CRC). Four 5-FU resistant CRC cell lines were established from parental cells through dose-escalation exposure of 5-FU. The resistant cells showed several morphological changes throughout the course of treatment. Resistance to 5-FU was confirmed through a cell viability assay. Wound healing and invasion assays demonstrated that the resistant cells experienced a decrease in migration and invasion except for one resistant cell line which displayed higher invasion. Using RT-PCR, the transcript levels of five protein methyltransferases (PMTs) were found to be dysregulated in the resistant cells. Western blotting showed that the protein expressions of EHMT2, PRMT5 and SETD7/9 decreased and that global protein methylation became dysregulated as the cells gained resistance. Western blotting demonstrated that the protein levels of E-cadherin, vimentin and Snail decreased in the resistant cell lines. This study showed that chemoresistance was not associated with EMT. Protein methylation and dysregulation of PMT expression may in part be responsible for the development of 5-FU resistance in the CRC cells. The second part of the project focused on overexpressing EHMT2 and PRMT5 in CRC cells to study their effects on EMT. Attempts were made to utilize molecular cloning techniques to generate EHMT2 and PRMT5 pcDNA3.1 plasmids. EHMT2 pLX304 and pLENTI3.4/V5-DEST plasmids were also purchased and were transfected directly into CRC cells. Through sub-cloning procedures, FLAG-tagged PRMT5 pcDNA3.1 plasmids were generated and transfected into SW480 cells. Western blotting did not reveal the overexpression of PRMT5. The overexpression of the PMTs was also investigated using small-activating RNAs, however the overexpression of the two PMTs was also not detected. It is still unclear whether EHMT2 or PRMT5 induce EMT in CRC. Description: M.Sc.(Melit.) Sun, 01 Jan 2023 00:00:00 GMT /library/oar/handle/123456789/117444 2023-01-01T00:00:00Z /library/oar/handle/123456789/113260 Title: Investigating the anti-cancer effects of α-solanine on glioblastoma cell-lines for in-vitro evaluation against the chemotherapeutic standard-of-care Abstract: Despite optimal treatment, glioblastoma multiforme (GBM) has an abysmal associated prognosis of approximately 15 months. Published literature has increasingly demonstrated the potential of phytochemicals as putative agents against cancer. α-solanine, a glycoalkaloid derived from plants belonging to the genus Solanum, has emerged as a promising anti-cancer molecule. Here, the efficacy of α-solanine versus temozolomide (TMZ) against U87MG, U251 and T98G GBM cell lines in-vitro was investigated. Viability, migration, and invasion assays were conducted to assess α-solanine’s anti-cancer potential in comparison to TMZ. Moreover, the effect of α-solanine on cell death was investigated on a cellular level through fluorescent imaging and flow cytometry, and on a molecular level through rt-PCR and proteome profiling assays. The GBM cell lines used in the study were confirmed to be IDHwildtype according to the WHO 2021 CNST classification. α-solanine induced potent cytotoxic on all GBM lines, with IC50 ranging between 19.66 µM – 22.87 µM, while also demonstrating significantly inhibiting GBM cell migration, in comparison to TMZ treatment. Fluorescent imaging and flow-cytometry demonstrated increased occurrence of autophagic cell death, however this finding was not statistically different between α-solanine and control treatments. Rt-qPCR and anti-body array profiling demonstrated upregulation of both apoptotic and autophagy proteins. The upregulation of BECN1 at both RNA and protein levels suggests its key role in α-solanine-induced cell death. Additionally, α-solanine may be an inducer of mitophagy through the upregulation of BNIP3L. Further investigations are required to consolidate α-solanine's effects on GBM cells, and the specific mechanisms of cell death it induces. Results presented in this study contribute to the search for novel and effective treatments for GBM. Further work should strive to increase the number biological replicates for the experiments conducted to and carry out alternative methods to strengthen this study’s findings. Moreover, in-vivo experiments and testing using patient-derived GBM tissue to better evaluate the clinical potential of α-solanine. Description: M.Sc.(Melit.) Sun, 01 Jan 2023 00:00:00 GMT /library/oar/handle/123456789/113260 2023-01-01T00:00:00Z