Browsing by Author "Nsingwane, Zanele"

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    The biochemical functions of the Retinoblastoma binding protein 6 (RBBP 6) isoforms in metabolic reprogramming occurring during carcinogenesis
    (2018) Nsingwane, Zanele
    ABSTRACT The Retinoblastoma binding protein 6 is dysregulated in most cancers, indicating it may play a role in metabolic reprograming- a hallmark of carcinogenesis. Its human isoforms have been shown to play diverse roles in apoptosis. This study aimed to elucidate biochemical roles of RBBP6 isoforms in metabolic reprogramming during carcinogenesis. Drosophila melanogaster wild type and p53 null mutants were treated with drug permutations of irinotecan (DNA damaging agent) and exogenous pyruvate to perturb metabolism. Moreover, using RT-PCR and Western blot expression profiles of SNAMA (Drosophila Orthologue of RBBP6) isoforms were shown followed by survival studies to investigate the effects of these drugs. Furthermore, using bioinformatics the domains of RBBP6 isoforms in various species were shown. Results indicate that RBBP6 isoforms show contrasting expression patterns. Furthermore, exogenous pyruvate protects the wild type flies from irinotecan toxicity while killing p53 null mutants. RBBP6 proves to be a potential druggable target for chemotherapy.
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    Identification of (Novel) Immune Targets with Potential Roles in the Progression of Pancreatic Ductal Adenocarcinoma (PDAC)
    (University of the Witwatersrand, Johannesburg, 2024) Nsingwane, Zanele; Nweke, Ekene
    Background: Pancreatic ductal adenocarcinoma (PDAC) is a lethal cancer with a growing incidence and mortality despite novel therapeutic strategies. Its aggressiveness and difficulty to treat suggest the need for a better understanding of associated molecular mechanisms which could be targeted for treatment. The complement signalling pathway may play diverse roles in PDAC by eliciting an immune response, inducing inflammatory responses, and may elevate pathways linked to chemoresistance. However, their role in the progression of PDAC is not fully understood. This study aimed to identify potential immune response-related targets in a group of patients. Methods: In this study, 30 tissue samples (tumours and corresponding normal tissues) were obtained from 15 PDAC patients, 34 plasma samples were obtained from 25 PDAC patients, 6 patients with chronic pancreatitis, and 3 healthy control participants. Targeted pathway-specific PCR analysis was conducted to determine the gene expression profiles of immune-response-related genes. The circulating levels of complement proteins C3 and C5 were further investigated. Pharmacological inhibition of the complement pathway in MIA PaCa-2 pancreatic cancer cell lines was performed and the effect on cells was assessed by cell proliferation, cell migration, and cell cycle assays. Finally, SWATH-mass spectrometry was performed to identify potential molecular mechanisms during inhibition. Results: The results identified C3 to be overly expressed in early PDAC compared to later stages in plasma (p=0.047). Pharmacological inhibition of the complement pathway led to increased cell growth (p<0.0001), proliferation (p=0.001) and migration (p=0.002) in vitro. Proteomic analysis implicated several proteins such as the mitochondrial and histone proteins, that could play a role in inducing this phenotype. Conclusion: Both Complement C3 and C5 are elevated in PDAC samples compared to healthy ones. Furthermore, the inhibition of the complement pathway was shown in vitro to result in a more aggressive phenotype by stimulating cellular growth, proliferation, and migration, indicating the involvement of complement C3 and C5 in tumour progression. This study helps to further delineate the role of the complement pathway in PDAC progression.