Browsing by Author "Baichan, Pavan"

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    Potential protein biomarker discovery for gallbladder cancer in a South African cohort
    (2024) Baichan, Pavan
    Gallbladder cancer (GBC) has a poor prognosis with the prevalence of GBC varying according to geographical location. The prevalence of GBC in South Africa is poorly tracked, and the molecular mechanisms associated with GBC in African patients are inadequately understood. This study aimed to determine dysregulated proteins in tissue and blood plasma in South African GBC patients to identify potential molecular mechanisms of disease progression and plausible biomarkers. Following ethical approval, tissue from 27 GBC, 13 gallstone disease (GD), and five normal tissues were obtained. Blood plasma was collected from 54 GBC and 73 benign biliary pathology (BBP) patients who consented to the study. A bottom-up proteomics approach was undertaken, using PAC and HILIC digestion methods, and SWATHMS for quantitative proteomic profiling. Hierarchical cluster analysis, PCA analysis, and Spearman’s rank correlation analysis were performed. Furthermore, pathway and network analyses were conducted. There were 62, 194, and 105 dysregulated proteins in the GBC/Normal, GBC/GD, and GD/Normal group comparisons, respectively, and 33 dysregulated proteins in the GBC/BBP plasma comparison. The dysregulated proteins in GBC patients enriched pathways involved in smooth muscle contraction, metabolism, extracellular matrix organisation and interactions, innate immunity, and platelet and neutrophil degranulation. Further analysis showed that S100A8 and S100A9 were downregulated in GBC plasma patients with GD history compared to those with no GD history. Additionally, APOE and ITIH3 were elevated in non-metastatic staging GBC patients. Seven proteins were found to be commonly dysregulated in GBC/GD and GBC/BBP comparisons and another two proteins were commonly dysregulated in the GBC/Normal, GBC/GD, and GBC/BBP comparisons, termed “Commonly dysregulated proteins (CDPs)”. Quality control assessment of the MS2 fragment ion chromatograms of the CDPs indicated strong signal-to-noise ratios and correct fragment-to-precursor matching. The CDPs could distinguish between GBC and controls and the Spearman’s rank correlation test showed significant correlations between the expression of the CDPs. The identified dysregulated proteins aid in further understanding the molecular mechanisms associated with GBC in patients with African ancestry. The alteration of specific proteins in tissue and plasma samples suggests their potential use as biomarkers for GBC patients in this sample cohort.
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    Targeting LRP/LR for the treatment of metastatic lung and colorectal cancer through impediment of telomerase activity
    (2018) Baichan, Pavan
    The 37 kDa/67 kDa laminin receptor (LRP/LR) plays a vital role in the malignancy of various cancer types contributing to invasion, adhesion, apoptosis evasion, proliferation and tumour angiogenesis. In addition, LRP/LR interacts with the catalytic reverse transcriptase subunit, TERT, of the ribonucleoprotein telomerase. Both LRP/LR and telomerase are implicated in cancer progression and knockdown of LRP/LR causes a decrease in telomerase activity in breast cancer cells. In the current study, LRP/LR was downregulated in lung adenocarcinoma (A549) and late-stage colorectal carcinoma (DLD-1) cells in an attempt to impede telomerase activity and ultimately impede cancer progression. Western blotting analysis showed a significant decrease in LRP/LR levels in HEK293 (Human Embryonic Kidney Cells) and A549 cells after siRNA mediated LRP/LR knockdown. To confirm LRP/LR knockdown confocal microscopy was performed; a reduction in LRP/LR protein levels was observed which also resulted in a subsequent decrease in hTERT mRNA levels with a corresponding decrease in hTERT levels in HEK293, A549, and DLD-1 cell lines. Furthermore, siRNA mediated knockdown of LRP/LR significantly decreased telomerase activity in HEK293, A549, and DLD-1 cells. The effect of LRP/LR downregulation on cellular viability was investigated via the MTT assay and a significant decrease in cell viability in A549 and DLD-1 cells was observed. Since downregulation of LRP/LR impedes telomerase activity and decreases cell viability, siRNAs directed against LRP mRNA acts as potential alternative therapeutic tools for treatment of lung adenocarcinoma and late-stage colorectal carcinoma.