Pusat Pengajian Sains Kesihatan - Tesis

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Anti cancer effect of paddy husk extracts in human salivary gland epidermoid cancer cells in vitro model
(2024-02)
Al-Azazi, Entesar Ahmed Abdullah
Global agriculture produces millions of tons of waste yearly. Paddy husk is an inedible agriculture waste obtained during the process of rice milling. Studies reported that it has chemopreventive potential due to the presence of related phytochemicals. The aim of this study is to elucidate the presence of anti-cancer related phytochemicals from paddy husk extract and evaluate its inhibitory and anti-proliferative effects against human submaxillary salivary gland epidermoid carcinoma cells (HTB-41). Two types of solvent for paddy husk extract have been used; water and aqueous methanol. The phytochemical constituents of paddy husk extracts were identified using GC-MS. The inhibitory activity and cytotoxicity analysis was calculated using Trypan Blue Exclusion Assay (TBEA). Apoptosis and cell cycle analysis were evaluated by flow cytometer, and cell morphology post treatment was analysed ultrastructurally, while Western blot was performed for proteomic analysis. Our results showed presence of vitamin E and other phytochemicals in paddy husk extracts. Both water and aqueous methanol extracts demonstrated inhibitory activity on HTB- 41 cells where IC50 dose of water extract (400 μg/ml) managed to reduce cell viability to 53.0 % and IC50 dose of aqueous methanol extract (200 μg/ml) managed to reduce cell viability to 51.12 % without exhibiting any significant cytotoxic effects. Apoptosis analysis revealed that water and aqueous methanol extracts induce apoptosis effect on HTB-41 as supported with microscopic findings of cell shrinkage, membrane blebbing and apoptotic bodies, meanwhile, Hoechst 33342 staining showed nuclear shrinkage and fragmentation. Flow cytometry analysis demonstrated that paddy husk extracts promote a significant amount of apoptotic cellular population from 76.00% (untreated) to 47.86% (paddy husk water extract) and 43.13% (paddy husk aqueous methanol) and arresting the cells at S-phase from 19.90% (control) to 36.90 % (paddy husk aqueous methanol extract) and 27.86 % (paddy husk water extract). Western blot analysis reveals that apoptosis was induced through caspase 3-mediated intrinsic pathway. Pro-apoptotic and tumour suppressor proteins; Bax, p27kip1 expressed higher (P <0.05), while anti-apoptotic protein, Bcl-2 downregulated after treatment (P <0.01). This leads to increase of caspase 9 expression which in turn activate caspase 3 and 7 leading to cell apoptosis. In conclusion, the presence of phytochemicals in paddy husk especially in aqueous methanol extract successfully showed better inhibitory and anti-proliferative effects on the human submaxillary salivary gland epidermoid carcinoma cells (HTB-41), while it acted in a tumour-selective manner by not inducing any significant changes on human gingival fibroblast cell (HGF-1).
Dysregulation of transcriptomic profiles of mm1.s and u266 multiple myeloma cell lines treated with epigenetic inhibitors
(2024-09)
Ismail, Nor Hayati
Multiple myeloma (MM) is a hematological malignancy characterized by the uncontrolled proliferation of plasma cells in the bone marrow. Epigenetic dysregulation plays a pivotal role in MM pathogenesis, making epigenetic inhibitors promising therapeutic targets. This study examines the effects of three epigenetic inhibitors—Trichostatin A (TSA), Panobinostat (PAN), and 5-azacytidine (5-AZA) on MM1.S and U266 cell lines, focusing on transcriptomic dysregulation and the identification of core genes associated with survival outcomes. Dose-response curves revealed that all three inhibitors inhibited cell proliferation in a dose-dependent manner, with PAN showing the most potent anti-proliferative effect at the half maximal inhibitory concentration (IC50) dose. Flow cytometry analysis indicated significant changes in cell cycle distribution upon treatment. TSA, PAN, and 5-AZA induced G0/G1 phase arrest, suppression in S phase and no changes observed in G2/M phase in MM1.S cells and U266 cells. Apoptosis assays demonstrated that MM1.S cell lines experienced late apoptosis with the highest impact induced by PAN. Meanwhile, U266 cell lines demonstrated early apoptosis event after treatment with epigenetic inhibitors and the most profound impact induced by 5-AZA. KEGG enrichment analysis of both MM cell lines treated with these epigenetic inhibitors identified significant pathways involving cell adhesion molecules, microRNAs in cancer, and viral protein interactions with cytokines and receptors. Notably, this study also demonstrated that PAN and 5-AZA treatments upregulated certain core histone genes (H2A, H2B, H3, H4), co-impacting chromatin structure and gene regulation, thus influencing cellular processes and therapeutic responses. Furthermore, Kaplan-Meier plot analysis revealed that core genes linked to transcriptomic dysregulation were significantly associated with improved overall survival (OS) outcomes. The highest number of survival-associated core genes was found in 5-AZA-treated cell lines. Specifically, 5-AZA treatment increased the expression of similar core genes in both MM1.S and U266 cells, downregulating KIF20A, KIF4A, and PLK1, which correlated significantly with improved OS rate (log-rank P: 1.4e-16). In PAN-treated MM cell lines, ORC1, MCM2, MCM5, and CXCL1 were identified as core genes with therapeutic potential. TSA-treated U266 cell lines revealed more significant core genes than MM1.S cell lines, with APOE emerging as a key gene linked to improved survival outcomes (log-rank P < 1e-16). Overall, this study provides comprehensive insights into the transcriptomic alterations induced by epigenetic inhibitors in MM cell lines. These findings enhance the understanding of MM pathogenesis and offer potential therapeutic targets for treating this challenging disease.
Investigating the expression of soluble pd-l1 (spd-l1) of breast cancer patients using elisa in Hospital USM, Kelantan
(2024-04)
Anwar, Nur Amira Khairil
There are limited data on soluble PD-L1 (sPD-L1) in breast cancer, particularly those involving Asian (Malaysian) women, despite the fact that increased serum and plasma levels of sPD-L1 have been observed in numerous malignancies. This study was designed to achieve three aims: (1) to recruit breast cancer patients at Hospital University Sains Malaysia (HUSM) and examine the overall survival (OS) with clinicopathological properties and patient baseline, (2) to develop a sensitive and specific enzyme-linked immunosorbent assay (ELISA) using commercialised PD-L1 monoclonal antibody clones (mAb), 22C3 (Dako) and 28-8 (Abcam) for sPD-L1 detection and measurement in human peripheral blood , and finally (3) measure sPD-L1 level using the developed ELISA followed by analyse its correlation and OS with clinical characteristics in breast cancer patients at HUSM. Blood specimens were obtained from three cohorts of breast cancer patient: 92 malignant, 16 benign and 23 healthy controls. Our study demonstrated that triple negative breast cancer (TNBC) molecular subtype have lower OS than the non-TNBC (53 months (SD 5.4 months) vs 272.7 months (SD 7.5 months), p= 0.029, log-rank test). Similarly, patients presenting with advanced tumour staging at diagnosis has poorer prognostic (p<0.001, log-rank test). Using 22C3 as the capture antibody, and clone 28-8 as the detection antibody, a sandwich ELISA was successfully developed with the limit of detection (LoD) of 0.063 ng/mL in human serum and 0.078 ng/mL in human plasma. The median serum sPD-L1 concentration of malignant and benign patient cohorts was significantly elevated compared to the healthy cohorts (12.50 ng/mL vs 13.97 ng/mL vs 8.75 ng/mL, p<0.05). Optimal cut-off value of serum sPD-L1 for this study was 8.84 ng/mL. Significant association existed between elevated serum sPD-L1 levels and menarche age, ethnicity, birth control usage, comorbidity and HER2 status (p<0.05). Menarche age and birth control were identified as independent variables impacting sPD-L1 level by multivariate analysis. However, the OS for patients with high vs low sPD-L1 level was not significant (266.3 months (SD 9.3 months) vs 60.0 months (SD 3.3 months), p=0.647, log-rank test). Additionally, there was no discernible correlation between tissue PD-L1 and serum sPD-L1 levels (p= 0.275, U-test). Elevated blood levels of sPD-L1 were strongly related with a number of clinical traits, and this relationship justifies the need for additional research for diagnostic and prognostic of breast cancer patients.
Proteomics approaches in identification of key signalling pathways associated with collagen type 1-induced osteogenic differentiation of dental stem cells
(2024-07)
Nasir, Nur Julia Nabila
Collagen type 1 (Col-1) is a promising scaffolding material in bone regeneration approach. However, the predominant signalling pathway involved when dental pulp stem cells (DPSC) cultured on the scaffold are still poorly understood. This study analysed the stemness of the DPSC prior to the studies of relevant signalling pathways involved and the proteomic profiles to determine the mechanism underlying the Col-1 induced osteogenesis. Characterisation of DPSC were analysed via its morphology, MSC surface markers, population doubling level as well as differentiation capacity. For the signalling pathways analysis, cells were grouped into complete culture medium (CCM; negative control), osteogenic induction medium (OIM; positive control) and Col-1 without and with three different pathway inhibitors: LY294002 (PI3K/AKT inhibitor), LY23200882 (TGF-β/Smad inhibitor) and PD98059 (MAPK/ERK inhibitor). Western blot analysis over 7, 14, and 21 days and LC-MS/MS proteomic profiling on day 21 revealed that the PI3K/AKT signalling pathway is crucial for the osteogenic differentiation of DPSC on both OIM and Col-1 group. PI3K/AKT pathway was predominant throughout the 21 days of Col-1 induced osteogenesis, while MAPK/ERK and TGF-β/Smad was more relevant at earlier and later stage, respectively. Crosstalk between signalling molecules showed bidirectional or unidirectional dependent to each other, where AKT activation can be influenced by Smad, but not vice versa. Likewise, Smad activation can be influenced by ERK1/2, but not the other way around. Proteomic profiling of Col-1 induced osteogenesis showed majority of the proteins were associated with glycolysis, carbon metabolism, biosynthesis of amino acid and focal adhesion.
The study of early orthodontic screening and referral practices by dental therapists in Malaysia
(2024-03)
Nie, Lim Yen
In Malaysia, the orthodontic treatment needs of schoolchildren are high. Effective orthodontic treatment delivery depends on timely referrals of cases that have undergone an appropriate screening process. Dental therapists are among the first to identify any malocclusion in Malaysian primary schoolchildren. This study aimed to determine the prevalence of early orthodontic screening and referral practices by dental therapists among primary schoolchildren. The association between dental therapists’ referral practice and the training of dental therapists were determined. A cross-sectional study was conducted among 360 dental therapists in Malaysia. The questionnaire tool was adapted from the study of Lim et al. and translated into Malay. The adapted and translated questionnaire was pre-tested. The following variables were gathered using an online self-administered questionnaire: (1) the socio-demographic profile, (2) orthodontic screening and referral practices, (3) training of dental therapists, and (4) views on orthodontic treatment. A stratified random sampling was done. Descriptive analysis and bivariate analysis (Fisher’s Exact Test and Spearman correlation) were conducted on collected data using IBM SPSS (version 26). In addition, SPSS Modeler (version 18.0.0) was used to visually explore the co-occurrence frequency of the variables via the web graphs. This survey obtained a response rate of 97.8% (n=352). The study revealed that less than one-quarter of the dental therapists (22.7%) performed orthodontic screening on all primary schoolchildren, and almost one-third (32.7%) did not routinely do orthodontic screening. The common orthodontic assessment done during the orthodontic screening was overjet (92.8%), the presence of spacing or crowding (92.4%), overbite (86.9%) and the presence of crossbite (78.9%). Almost half of the dental therapists (47.7%) preferred dentists’ advice during screening instead of using guidelines (32.9%). More than half of them (65.6%) referred less than five patients per month, while almost one-quarter (24.1%) did not refer patients. Dental therapists used a variety of referral documents. The average orthodontic referral number is associated with exposure to orthodontic theory, practice and experience with orthodontic diagnosis during their career. In conclusion, this study obtained a high response rate. The orthodontic screening rate of dental therapists in all primary schoolchildren is poor. Variation in referral documents is identified. A standardized referral form from the school to the primary dental clinic is recommended to ensure timely monitoring and treatment of diagnosed cases. Oral health personnel working with schoolchildren are strongly encouraged to use a proforma in orthodontic screening and participate in continuing professional development (CPD).

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