10 research outputs found

    Evaluation of palbociclib in oral squamous cell carcinoma and the role of PIK3CA in conferring resistance / Nur Syafinaz Zainal

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    Lack of effective therapies remains a problem in the treatment of oral squamous cell carcinoma (OSCC), especially in patients with advanced tumors. OSCC development is driven by multiple aberrancies within the cell cycle pathway including amplification of cyclin D1 and loss of p16. Hence, cell cycle inhibitors of the CDK4/6-cyclin D axis are appealing targets for OSCC treatment. This study aimed to determine the potency of palbociclib and identify genetic features that are associated with palbociclib�s response in OSCC. It was demonstrated that 80% of OSCC cell lines were sensitive to palbociclib at sub-micromolar concentrations. Palbociclib-treated cells were arrested at G1 phase with concomitant reduction of phosphorylated-Rb. Consistently, it was found that palbociclib was effective in controlling tumor growth in mice. Importantly, this study identified palbociclib-resistant cells to harbour mutations in the PIK3CA gene. Using isogenic cell lines, PIK3CA-mutant cells were shown to be less responsive to palbociclib compared to wildtype cells. Despite the reduction of RB phosphorylation upon palbociclib treatment, PIK3CA-mutant cells upregulated CDK2 and cyclin E1 suggesting this to be the mechanism underlying resistance to palbociclib. Further, it was demonstrated that the combination of PF-04691502, a PI3K/mTOR inhibitor, with palbociclib completely controlled tumor growth in mice. This study provides a rationale for the inclusion of PIK3CA testing in clinical evaluation of CDK4/6 inhibitors and suggests combination approaches for further clinical studies

    Water quality and percentage of hard coral cover in Ambong Bay And Usukan Bay of Kota Belud, Sabah

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    "Water quality parameters need to be tested in an area to determine whether the area is contaminated with pollution such as fecal coliform and heavy metals pollution. Some of these pollutants are not toxic but if it exist in excess of that environment will lead harm to human life and other marine organisms such as fish, and coral since all these ecosystem linked with each other very well. A study was carried out to determine and to compare the water quality in Ambong Bay and Usukan Bay, besides to determine and to compare the percentage of hard coral cover between the two bays. It is also were carried out to determine the relationship between the water quality of the two bays and the percentage of hard coral cover. Fecal coliform analyses were done by using Membrane Filter (14F) method while heavy metals were done by Inductively Coupled Plasma-Otomic Emission Spectroscopy (ICP-OES). The results obtained showed that the in situ water parameter for both bays in terms of temperature (°C), pH, turbidity (NFU), salinity (psu), DO (mg/L) shows that it is in the range compared to National Water Quality Standards of Malaysia. Meanwhile for fecal coliform, Ambong Bay showed higher reading compared to Usukan Bay which was 1.44 CFU/100mL ± 1.20 to 4.70 CFU/100mL ± 1.03 respectively. For heavy metal analyses, Usukan Bay shows higher concentrations of Cd, Cr, Cu, Pb, Zn, and Al which were 0.003 mg/L ± 0.001,0.456 mg/L ± 0.058,0.991 mg/L ± 0.308,0.438 mg/L ± 0.049,2.917 mg/L ± 1.245, and 2.336 mg/L ± 0.344 respectively. While for the percentage of hard coral cover, Ambong Bay shows higher percentage but with less diverse type of coral growth compared to Usukan Bay. The statistical analysis of One way ANOVA showed that there were significance difference (p<0.05) for temperature, pH, turbidity, DO, fecal coliform and six heavy metals elements. Pearson's Correlation showed that only temperature shows relationship with the percentage of hard coral cover. From this study, it shows that Ambong Bay and Usukan Bay is contaminated with pollutants such as fecal coliform and heavy metals but the contamination is not too high and still can be acceptable

    Effects of palbociclib in oral squamous cell carcinoma and the role of PIK3CA in conferring resistance

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    Objective: Lack of effective therapies remains a problem in the treatment of oral squamous cell carcinoma (OSCC), especially in patients with advanced tumors. OSCC development is driven by multiple aberrancies within the cell cycle pathway, including amplification of cyclin D1 and loss of p16. Hence, cell cycle inhibitors of the CDK4/6-cyclin D axis are appealing targets for OSCC treatment. Here, we determined the potency of palbociclib and identified genetic features that are associated with the response of palbociclib in OSCC. Methods: The effect of palbociclib was evaluated in a panel of well-characterized OSCC cell lines by cell proliferation assays and further confirmed by in vivo evaluation in xenograft models. PIK3CA-mutant isogenic cell lines were used to investigate the effect of PIK3CA mutation towards palbociclib response. Results: We demonstrated that 80% of OSCC cell lines are sensitive to palbociclib at sub-micromolar concentrations. Consistently, palbociclib was effective in controlling tumor growth in mice. We identified that palbociclib-resistant cells harbored mutations in PIK3CA. Using isogenic cell lines, we showed that PIK3CA mutant cells are less responsive to palbociclib as compared to wild-type cells with concurrent upregulation of CDK2 and cyclin El protein levels. We further demonstrated that the combination of a PI3K/mTOR inhibitor (PF-04691502) and palbociclib completely controlled tumor growth in mice. Conclusions: This study demonstrated the potency of palbociclib in OSCC models and provides a rationale for the inclusion of PIK3CA testing in the clinical evaluation of CDK4/6 inhibitors and suggests combination approaches for further clinical studies

    Zerumbone targets the CXCR4-RhoA and PI3K-mTOR signaling axis to reduce motility and proliferation of oral cancer cells

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    Background: The CXCR4-RhoA and PI3K-mTOR signaling pathways play crucial roles in the dissemination and tumorigenesis of oral squamous cell carcinoma (OSCC). Activation of these pathways have made them promising molecular targets in the treatment of OSCC. Zerumbone, a bioactive monocyclic sesquiterpene isolated from the rhizomes of tropical ginger, Zingiber zerumbet (L.) Roscoe ex Sm. has displayed promising anticancer properties with the ability to modulate multiple molecular targets involved in carcinogenesis. While the anticancer activities of zerumbone have been well explored across different types of cancer, the molecular mechanism of action of zerumbone in OSCC remains largely unknown. Purpose: Here, we investigated whether OSCC cells were sensitive towards zerumbone treatment and further determined the molecular pathways involved in the mechanism of action. Methods: Cytotoxicity, anti-proliferative, anti-migratory and anti-invasive effects of zerumbone were tested on a panel of OSCC cell lines. The mechanism of action of zerumbone was investigated by analysing the effects on the CXCR4-RhoA and PI3K-mTOR pathways by western blotting. Results: Our panel of OSCC cells was broadly sensitive towards zerumbone with IC50 values of less than 5 µM whereas normal keratinocyte cells were less responsive with IC50 values of more than 25 µM. Representative OSCC cells revealed that zerumbone inhibited OSCC proliferation and induced cell cycle arrest and apoptosis. In addition, zerumbone treatment inhibited migration and invasion of OSCC cells, with concurrent suppression of endogenous CXCR4 protein expression in a time and dose-dependent manner. RhoA-pull down assay showed reduction in the expression of RhoA-GTP, suggesting the inactivation of RhoA by zerumbone. In association with this, zerumbone also inhibited the PI3K-mTOR pathway through the inactivation of Akt and S6 proteins. Conclusion: We provide evidence that zerumbone could inhibit the activation of CXCR4-RhoA and PI3K-mTOR signaling pathways leading to the reduced cell viability of OSCC cells. Our results suggest that zerumbone is a promising phytoagent for development of new therapeutics for OSCC treatment

    Synergistic Growth Inhibition by Afatinib and Trametinib in Preclinical Oral Squamous Cell Carcinoma Models

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    Background: Given that aberrant activation of epidermal growth factor receptor family receptors (ErbB) is a common event in oral squamous cell carcinoma, and that high expression of these receptor proteins is often associated with poor prognosis, this rationalizes the approach of targeting ErbB signaling pathways to improve the survival of patients with oral squamous cell carcinoma. However, monotherapy with the ErbB blocker afatinib has shown limited survival benefits. Objectives: This study was performed to identify mechanisms of afatinib resistance and to explore potential afatinib-based combination treatments with other targeted inhibitors in oral squamous cell carcinoma. Methods: We determined the anti-proliferative effects of afatinib on a panel of oral squamous cell carcinoma cell lines using a crystal violet-growth inhibition assay, click-iT 5-ethynyl-2′-deoxyuridine staining, and cell-cycle analysis. Biochemical assays were performed to study the underlying mechanism of drug treatment as a single agent or in combination with the MEK inhibitor trametinib. We further evaluated and compared the anti-tumor effects of single agent and combined treatment by using oral squamous cell carcinoma xenograft models. Results: In this study, we showed that afatinib inhibited oral squamous cell carcinoma cell proliferation via cell-cycle arrest at the G0/G1 phase, and inhibited tumor growth in xenograft mouse models. Interestingly, we demonstrated reactivation of the mitogen-activated protein kinase (ERK1/2) pathway in vitro, which possibly reduced the effects of ErbB inhibition. Concomitant treatment of oral squamous cell carcinoma cells with afatinib and trametinib synergized the anti-tumor effects in oral squamous cell carcinoma-bearing mouse models. Conclusions: Our findings provide insight into the molecular mechanism of resistance to afatinib and support further clinical evaluation into the combination of afatinib and MEK inhibition in the treatment of oral squamous cell carcinoma. © 2019, Springer Nature Switzerland AG

    An unusual cause of tenosynovitis by group B streptococcus in the immunocompromised patient: a case report

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    This case report describes a 49-year-old immunocompromised woman with tenosynovitis of the left middle finger caused by Group B Streptococcus (GBS). She claimed that a fishbone picked over her left middle finger. An orthopaedic surgeon operated for incision and drainage of pus discharge, wound debridement of the left middle finger and A1 and A2 pulley release. Treatment was initiated with parenteral cefepime three times per day given the growth of mixed Enterobacter species on the culture media and continued with oral cefuroxime twice daily upon discharge for one week. Unfortunately, during the orthopaedic clinic follow-up, the wound was unclean with a slough and skin necrotic patch. Therefore, Ray’s amputation of the left middle finger proceeded. This case contributes to further investigation of the GBS tenosynovitis due to the rise in GBS invasive infections and shows the importance of early diagnosing and initiating treatment with antibiotics that are effective against this pathogen

    The 4717C > G polymorphism in periplakin modulates sensitivity to EGFR inhibitors

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    Abstract The use of EGFR inhibitors on oral squamous cell carcinoma (OSCC) as monotherapy yielded modest clinical outcomes and therefore would benefit from biomarkers that could predict which patient subsets are likely to respond. Here, we determined the efficacy of erlotinib in OSCC cell lines, and by comparing sensitive and resistant lines to identify potential biomarkers. We focused on the 4717C > G polymorphism in periplakin (PPL) where the CC genotype was associated with erlotinib resistance. To validate this, erlotinib-resistant cell lines harbouring CC genotype were engineered to overexpress the GG genotype and vice versa. Isogenic cell lines were then studied for their response to erlotinib treatment. We demonstrated that overexpression of the GG genotype in erlotinib-resistant lines sensitized them to erlotinib and inhibition of AKT phosphorylation. Similarly, the expression of the CC genotype conferred resistance to erlotinib with a concomitant increase in AKT phosphorylation. We also demonstrated that cell lines with the CC genotype generally are more resistant to other EGFR inhibitors than those with the GG genotype. Overall, we showed that a specific polymorphism in the PPL gene could confer resistance to erlotinib and other EGFR inhibitors and further work to evaluate these as biomarkers of response is warranted

    Time to treatment initiation and retrospective analysis of antiretroviral therapy outcomes among HIV-positive methadone maintenance therapy clients in Primary Health-care Centers, Kuantan, Pahang

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    Introduction: Methadone maintenance therapy (MMT) program helped to improve access to antiretroviral therapy (ART) among people who inject drugs (PWID) with human immunodeficiency virus (HIV). However, the time to treatment initiation (TTI) and outcomes of ART intervention in this population have scarcely been analyzed. Objectives: The aim of this study was to analyze the TTI and outcomes of ART among MMT clients in primary health-care centers in Kuantan, Pahang. Materials and Methods: This was a retrospective evaluation of MMT clients from 2006 to 2019. The TTI was calculated from the day of MMT enrolment to ART initiation. The trends of CD4 counts and viral loads were descriptively evaluated. Cox proportional hazard model was used to analyze the survival and treatment retention rate. Results: A total of 67 MMT clients from six primary health-care centers were HIV-positive, of which 37 clients were started on ART. The mean TTI of ART was 27 months. The clients who were given ART had a mean CD4 count of 119 cells/mm3 at baseline and increased to 219 cells/mm3 after 6 months of ART. Only two patients (5.4%) in the ART subgroup had an unsuppressed viral load. The initiation of ART had reduced the risk of death by 72.8% (hazard ratio = 0.27, P = 0.024), and they are 13.1 times more likely to remain in treatment (P < 0.01). Conclusion: The TTI of ART was delayed in this population. MMT clients who were given ART have better CD4 and viral load outcomes, helped reduced death risk and showed higher retention rates in MMT program

    DNA Vaccines Targeting Novel Cancer-Associated Antigens Frequently Expressed in Head and Neck Cancer Enhance the Efficacy of Checkpoint Inhibitor

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    HPV-independent head and neck squamous cell carcinoma (HNSCC) is a common cancer globally. The overall response rate to anti-PD1 checkpoint inhibitors (CPIs) in HNSCC is ~16%. One major factor influencing the effectiveness of CPI is the level of tumor infiltrating T cells (TILs). Converting TILlow tumors to TILhigh tumors is thus critical to improve clinical outcome. Here we describe a novel DNA vaccines to facilitate the T-cell infiltration and control tumor growth. We evaluated the expression of target antigens and their respective immunogenicity in HNSCC patients. The efficacy of DNA vaccines targeting two novel antigens were evaluated with or without CPI using a syngeneic model. Most HNSCC patients (43/44) co-expressed MAGED4B and FJX1 and their respective tetramer-specific T cells were in the range of 0.06-0.12%. In a preclinical model, antigen-specific T cells were induced by DNA vaccines and increased T cell infiltration into the tumor, but not MDSC or regulatory T cells. The vaccines inhibited tumor growth and improved the outcome alone and upon combination with anti-PD1 and resulted in tumor clearance in approximately 75% of mice. Pre-existence of MAGED4B and FJX1-reactive T cells in HNSCC patients suggests that these widely expressed antigens are highly immunogenic and could be further expanded by vaccination. The DNA vaccines targeting these antigens induced robust T cell responses and with the anti-PD1 antibody conferring excellent tumor control. This opens up an opportunity for combination immunotherapy that might benefit a wider population of HNSCC patients in an antigen-specific manner

    Public Awareness and Practices Towards Self-Medication with Antibiotics Among Malaysian Population: Questionnaire Development and Pilot Testing

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