Displaying publications 1 - 20 of 34 in total

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  1. Fulltext The potential for chemical mixtures from the environment to enable the cancer hallmark of sustained proliferative signalling
    Engström W, Darbre P, Eriksson S, Gulliver L, Hultman T, Karamouzis MV, et al.
    Carcinogenesis, 2015 Jun;36 Suppl 1:S38-60.
    PMID: 26106143 DOI: 10.1093/carcin/bgv030
    The aim of this work is to review current knowledge relating the established cancer hallmark, sustained cell proliferation to the existence of chemicals present as low dose mixtures in the environment. Normal cell proliferation is under tight control, i.e. cells respond to a signal to proliferate, and although most cells continue to proliferate into adult life, the multiplication ceases once the stimulatory signal disappears or if the cells are exposed to growth inhibitory signals. Under such circumstances, normal cells remain quiescent until they are stimulated to resume further proliferation. In contrast, tumour cells are unable to halt proliferation, either when subjected to growth inhibitory signals or in the absence of growth stimulatory signals. Environmental chemicals with carcinogenic potential may cause sustained cell proliferation by interfering with some cell proliferation control mechanisms committing cells to an indefinite proliferative span.
  2. Fulltext The mediation effect of burnout and moderation effect of social support on work-family conflictturnover intention relationship among malaysian woman engineers: a proposed framework and methodology
    Hamid RA, Ungku Ahmad UN
    Journal of Advanced Research Design, 2015;15(1):19-35.
    MyJurnal
    An increasing number of women participate in the work force due to socio-economic development result a big impact to work and family institution. Failure to meet demand for both work and family lead to work-family conflict that may give negative consequences on work and family. An example of major work-related outcome is burnout which can lead to turnover intention. Social support has been identified as an important resources that can reduce work-family conflict and burnout. This paper aims to identify the relationship between work-family conflict and turnover intention and also the mediation effect of burnout on work-family conflict and turnover intention relationship. It is proposed that there will be a positive relationship between work-family conflict and turnover intention and there is an indirect relationship between work-family conflict and turnover intention through the mediation effect of burnout. Social support from work and family is proposed to moderate the relationship between work-family conflict and burnout. Furthermore it is proposed that the strength of relationship between work-family conflict and turnover intention depends on the mediation effect of burnout and moderating effect of social support.
  3. Fulltext The impact of low-dose carcinogens and environmental disruptors on tissue invasion and metastasis
    Ochieng J, Nangami GN, Ogunkua O, Miousse IR, Koturbash I, Odero-Marah V, et al.
    Carcinogenesis, 2015 Jun;36 Suppl 1:S128-59.
    PMID: 26106135 DOI: 10.1093/carcin/bgv034
    The purpose of this review is to stimulate new ideas regarding low-dose environmental mixtures and carcinogens and their potential to promote invasion and metastasis. Whereas a number of chapters in this review are devoted to the role of low-dose environmental mixtures and carcinogens in the promotion of invasion and metastasis in specific tumors such as breast and prostate, the overarching theme is the role of low-dose carcinogens in the progression of cancer stem cells. It is becoming clearer that cancer stem cells in a tumor are the ones that assume invasive properties and colonize distant organs. Therefore, low-dose contaminants that trigger epithelial-mesenchymal transition, for example, in these cells are of particular interest in this review. This we hope will lead to the collaboration between scientists who have dedicated their professional life to the study of carcinogens and those whose interests are exclusively in the arena of tissue invasion and metastasis.
  4. Fulltext The hexane fraction of Ardisia crispa Thunb. A. DC. roots inhibits inflammation-induced angiogenesis
    Hamsin DE, Hamid RA, Yazan LS, Taib CN, Ting YL
    BMC Complement Altern Med, 2013;13:5.
    PMID: 23298265 DOI: 10.1186/1472-6882-13-5
    Ardisia crispa (Myrsinaceae) is used in traditional Malay medicine to treat various ailments associated with inflammation, including rheumatism. The plant's hexane fraction was previously shown to inhibit several diseases associated with inflammation. As there is a strong correlation between inflammation and angiogenesis, we conducted the present study to investigate the anti-angiogenic effects of the plant's roots in animal models of inflammation-induced angiogenesis.
  5. Fulltext The effect of environmental chemicals on the tumor microenvironment
    Casey SC, Vaccari M, Al-Mulla F, Al-Temaimi R, Amedei A, Barcellos-Hoff MH, et al.
    Carcinogenesis, 2015 Jun;36 Suppl 1:S160-83.
    PMID: 26106136 DOI: 10.1093/carcin/bgv035
    Potentially carcinogenic compounds may cause cancer through direct DNA damage or through indirect cellular or physiological effects. To study possible carcinogens, the fields of endocrinology, genetics, epigenetics, medicine, environmental health, toxicology, pharmacology and oncology must be considered. Disruptive chemicals may also contribute to multiple stages of tumor development through effects on the tumor microenvironment. In turn, the tumor microenvironment consists of a complex interaction among blood vessels that feed the tumor, the extracellular matrix that provides structural and biochemical support, signaling molecules that send messages and soluble factors such as cytokines. The tumor microenvironment also consists of many host cellular effectors including multipotent stromal cells/mesenchymal stem cells, fibroblasts, endothelial cell precursors, antigen-presenting cells, lymphocytes and innate immune cells. Carcinogens can influence the tumor microenvironment through effects on epithelial cells, the most common origin of cancer, as well as on stromal cells, extracellular matrix components and immune cells. Here, we review how environmental exposures can perturb the tumor microenvironment. We suggest a role for disrupting chemicals such as nickel chloride, Bisphenol A, butyltins, methylmercury and paraquat as well as more traditional carcinogens, such as radiation, and pharmaceuticals, such as diabetes medications, in the disruption of the tumor microenvironment. Further studies interrogating the role of chemicals and their mixtures in dose-dependent effects on the tumor microenvironment could have important general mechanistic implications for the etiology and prevention of tumorigenesis.
  6. Fulltext Telehealth utilization during the Covid-19 pandemic: A systematic review
    Garfan S, Alamoodi AH, Zaidan BB, Al-Zobbi M, Hamid RA, Alwan JK, et al.
    Comput Biol Med, 2021 Nov;138:104878.
    PMID: 34592585 DOI: 10.1016/j.compbiomed.2021.104878
    During the coronavirus disease (COVID-19) pandemic, different technologies, including telehealth, are maximised to mitigate the risks and consequences of the disease. Telehealth has been widely utilised because of its usability and safety in providing healthcare services during the COVID-19 pandemic. However, a systematic literature review which provides extensive evidence on the impact of COVID-19 through telehealth and which covers multiple directions in a large-scale research remains lacking. This study aims to review telehealth literature comprehensively since the pandemic started. It also aims to map the research landscape into a coherent taxonomy and characterise this emerging field in terms of motivations, open challenges and recommendations. Articles related to telehealth during the COVID-19 pandemic were systematically searched in the WOS, IEEE, Science Direct, Springer and Scopus databases. The final set included (n = 86) articles discussing telehealth applications with respect to (i) control (n = 25), (ii) technology (n = 14) and (iii) medical procedure (n = 47). Since the beginning of the pandemic, telehealth has been presented in diverse cases. However, it still warrants further attention. Regardless of category, the articles focused on the challenges which hinder the maximisation of telehealth in such times and how to address them. With the rapid increase in the utilization of telehealth in different specialised hospitals and clinics, a potential framework which reflects the authors' implications of the future application and opportunities of telehealth has been established. This article improves our understanding and reveals the full potential of telehealth during these difficult times and beyond.
  7. S-phase arrest and apoptosis in human breast adenocarcinoma MCF-7 cells via mitochondrial dependent pathway induced by tricyclohexylphosphine gold (I) n-mercaptobenzoate complexes
    Pian AK, Foong CP, Hamid RA
    Life Sci, 2022 Dec 15;311(Pt B):121161.
    PMID: 36375571 DOI: 10.1016/j.lfs.2022.121161
    We have previously reported the inhibition of thioredoxin reductase (TrxR) and invasion by tricyclohexylphosphine gold (I) n-mercaptobenzoate (n = 2, 3, 4) labeled as 1-3 towards MCF-7 cells, in vitro. Nevertheless, the mode of death and its apoptotic pathway has yet to be revealed. The main aim of this study is to investigate the anti-neoplastic activity of this phosphanegold (I) thiolates against breast adenocarcinoma cells, MCF-7. Herein, we explored the role of gold(I) series, 1-3 for their apoptosis-inducing ability against MCF-7 cells. They were scrutinized for their antiproliferative activities which exhibited their IC50 values of 8.14 μM ± 0.10, 7.26 μM ± 0.33, and 9.03 μM ± 0.69, respectively, and indicated better cytotoxicities than that of cisplatin (positive control). Further, the mechanisms of their actions were studied by analyzing the status of ROS generation (by DCFH-DA), cytochrome c release (by ELISA), and activation of caspases 3/7, 8, 9, and 10, annexin V staining and cell cycle analysis by flow cytometry, respectively. It was observed that the compounds, 1-3 can promote ROS generation, cytochrome c release, and activation of caspases 3/7, caspase 8, caspase 9, and caspase 10 on MCF-7 cells. In addition, the compounds are shown to induce MCF-7 cell arrest at S-phase. Gene analysis via PCR array further clarified their effects by modulating the related genes upon the compounds' treatment. Further investigation on other breast cancer cells as well as in vivo studies on these compounds will further increase their potential as anti-breast cancer agents.
  8. Fulltext Role of biological Data Mining and Machine Learning Techniques in Detecting and Diagnosing the Novel Coronavirus (COVID-19): A Systematic Review
    Albahri AS, Hamid RA, Alwan JK, Al-Qays ZT, Zaidan AA, Zaidan BB, et al.
    J Med Syst, 2020 May 25;44(7):122.
    PMID: 32451808 DOI: 10.1007/s10916-020-01582-x
    Coronaviruses (CoVs) are a large family of viruses that are common in many animal species, including camels, cattle, cats and bats. Animal CoVs, such as Middle East respiratory syndrome-CoV, severe acute respiratory syndrome (SARS)-CoV, and the new virus named SARS-CoV-2, rarely infect and spread among humans. On January 30, 2020, the International Health Regulations Emergency Committee of the World Health Organisation declared the outbreak of the resulting disease from this new CoV called 'COVID-19', as a 'public health emergency of international concern'. This global pandemic has affected almost the whole planet and caused the death of more than 315,131 patients as of the date of this article. In this context, publishers, journals and researchers are urged to research different domains and stop the spread of this deadly virus. The increasing interest in developing artificial intelligence (AI) applications has addressed several medical problems. However, such applications remain insufficient given the high potential threat posed by this virus to global public health. This systematic review addresses automated AI applications based on data mining and machine learning (ML) algorithms for detecting and diagnosing COVID-19. We aimed to obtain an overview of this critical virus, address the limitations of utilising data mining and ML algorithms, and provide the health sector with the benefits of this technique. We used five databases, namely, IEEE Xplore, Web of Science, PubMed, ScienceDirect and Scopus and performed three sequences of search queries between 2010 and 2020. Accurate exclusion criteria and selection strategy were applied to screen the obtained 1305 articles. Only eight articles were fully evaluated and included in this review, and this number only emphasised the insufficiency of research in this important area. After analysing all included studies, the results were distributed following the year of publication and the commonly used data mining and ML algorithms. The results found in all papers were discussed to find the gaps in all reviewed papers. Characteristics, such as motivations, challenges, limitations, recommendations, case studies, and features and classes used, were analysed in detail. This study reviewed the state-of-the-art techniques for CoV prediction algorithms based on data mining and ML assessment. The reliability and acceptability of extracted information and datasets from implemented technologies in the literature were considered. Findings showed that researchers must proceed with insights they gain, focus on identifying solutions for CoV problems, and introduce new improvements. The growing emphasis on data mining and ML techniques in medical fields can provide the right environment for change and improvement.
  9. Quinone-rich fraction of Ardisia crispa (Thunb.) A. DC roots alters angiogenic cascade in collagen-induced arthritis
    Blin JA, Ali RM, Nurdin A, Hamid RA
    Inflammopharmacology, 2021 Jun;29(3):771-788.
    PMID: 34091811 DOI: 10.1007/s10787-021-00816-9
    Rheumatoid arthritis (RA) is a chronic joint disorder, of which, excessive angiogenesis is the well-established factor contributing to synovitis and joint destruction. Ardisia crispa (Primulaceae) is a medicinal herb with evidenced anti-angiogenic properties, attributed to 2-methoxy-6-undecyl-1,4-benzoquinone (BQ) found in its roots. However, it is still unclear how BQ is able to inhibit angiogenesis in RA. Hence, we investigated the anti-arthritic potential of quinone-rich fraction (QRF) separated from Ardisia crispa roots hexane extract (ACRH) by targeting angiogenesis on collagen-induced arthritis (CIA) in rats. The QRF was priorly identified by quantifying the BQ content in the fraction using GC-MS. Male Sprague-Dawley rats (n = 6) were initially immunised with type II collagen (150 µg) subcutaneously at the base of the tail on day 0. QRF (3, 10, and 30 mg/kg/day) and celecoxib (5 mg/kg/day) were orally administered for 13 consecutive days starting from day 14 post-induction, except for the vehicle and arthritic controls. QRF at all dosages moderately ameliorated the arthritic scores, ankle swelling, and hind paw oedema with no significant (p > 0.05) modulation on the bodyweights and organ weights (i.e., liver, kidney, and spleen). Treatment with QRF at 3, 10, and 30 mg/kg, significantly (p 
  10. Fulltext Non-alignment stagnation-point flow of a nanofluid past a permeable stretching/shrinking sheet: Buongiorno's model
    Hamid RA, Nazar R, Pop I
    Sci Rep, 2015;5:14640.
    PMID: 26440761 DOI: 10.1038/srep14640
    The paper deals with a stagnation-point boundary layer flow towards a permeable stretching/shrinking sheet in a nanofluid where the flow and the sheet are not aligned. We used the Buongiorno model that is based on the Brownian diffusion and thermophoresis to describe the nanofluid in this problem. The main purpose of the present paper is to examine whether the non-alignment function has the effect on the problem considered when the fluid suction and injection are imposed. It is interesting to note that the non-alignment function can ruin the symmetry of the flows and prominent in the shrinking sheet. The fluid suction will reduce the impact of the non-alignment function of the stagnation flow and the stretching/shrinking sheet but at the same time increasing the velocity profiles and the shear stress at the surface. Furthermore, the effects of the pertinent parameters such as the Brownian motion, thermophoresis, Lewis number and the suction/injection on the flow and heat transfer characteristics are also taken into consideration. The numerical results are shown in the tables and the figures. It is worth mentioning that dual solutions are found to exist for the shrinking sheet.
  11. Fulltext Metabolic reprogramming and dysregulated metabolism: cause, consequence and/or enabler of environmental carcinogenesis?
    Robey RB, Weisz J, Kuemmerle NB, Salzberg AC, Berg A, Brown DG, et al.
    Carcinogenesis, 2015 Jun;36 Suppl 1(Suppl 1):S203-31.
    PMID: 26106140 DOI: 10.1093/carcin/bgv037
    Environmental contributions to cancer development are widely accepted, but only a fraction of all pertinent exposures have probably been identified. Traditional toxicological approaches to the problem have largely focused on the effects of individual agents at singular endpoints. As such, they have incompletely addressed both the pro-carcinogenic contributions of environmentally relevant low-dose chemical mixtures and the fact that exposures can influence multiple cancer-associated endpoints over varying timescales. Of these endpoints, dysregulated metabolism is one of the most common and recognizable features of cancer, but its specific roles in exposure-associated cancer development remain poorly understood. Most studies have focused on discrete aspects of cancer metabolism and have incompletely considered both its dynamic integrated nature and the complex controlling influences of substrate availability, external trophic signals and environmental conditions. Emerging high throughput approaches to environmental risk assessment also do not directly address the metabolic causes or consequences of changes in gene expression. As such, there is a compelling need to establish common or complementary frameworks for further exploration that experimentally and conceptually consider the gestalt of cancer metabolism and its causal relationships to both carcinogenesis and the development of other cancer hallmarks. A literature review to identify environmentally relevant exposures unambiguously linked to both cancer development and dysregulated metabolism suggests major gaps in our understanding of exposure-associated carcinogenesis and metabolic reprogramming. Although limited evidence exists to support primary causal roles for metabolism in carcinogenesis, the universality of altered cancer metabolism underscores its fundamental biological importance, and multiple pleiomorphic, even dichotomous, roles for metabolism in promoting, antagonizing or otherwise enabling the development and selection of cancer are suggested.
  12. Fulltext Mechanisms of environmental chemicals that enable the cancer hallmark of evasion of growth suppression
    Nahta R, Al-Mulla F, Al-Temaimi R, Amedei A, Andrade-Vieira R, Bay SN, et al.
    Carcinogenesis, 2015 Jun;36 Suppl 1:S2-18.
    PMID: 26106139 DOI: 10.1093/carcin/bgv028
    As part of the Halifax Project, this review brings attention to the potential effects of environmental chemicals on important molecular and cellular regulators of the cancer hallmark of evading growth suppression. Specifically, we review the mechanisms by which cancer cells escape the growth-inhibitory signals of p53, retinoblastoma protein, transforming growth factor-beta, gap junctions and contact inhibition. We discuss the effects of selected environmental chemicals on these mechanisms of growth inhibition and cross-reference the effects of these chemicals in other classical cancer hallmarks.
  13. Isolation of a quinone-rich fraction from Ardisia crispa roots and its attenuating effects on murine skin tumorigenesis
    Yeong LT, Hamid RA, Yazan LS, Khaza'ai H
    Asian Pac J Cancer Prev, 2013;14(4):2301-5.
    PMID: 23725131
    Ardisia crispa (Family: Myrsinaceae) is an evergreen, fruiting shrub that has been traditionally used as folklore medicine. Despite a scarcity of research publications, we have succeeded in showing suppressive effects on murine skin papillomagenesis. In extension, the present research was aimed at determining the effect of a quinone-rich fraction (QRF) isolated from the same root hexane extract on both initiation and promotion stages of carcinogenesis, at the selected dose of 30 mg/kg. Mice (groups I-IV) were initiated with a single dose of 7,12-dimethylbenz(α)anthracene (DMBA, 100 μg/100 μl) followed by repeated promotion of croton oil (1%) twice weekly for 20 weeks. In addition, group I (anti-initiation) received QRF 7 days before and after DMBA; group II (anti-promotion) received QRF 30 minutes before each croton oil application; group III (anti-initiation/ promotion) was treated with QRF as a combination of group I and II. A further two groups served as vehicle control (group V) and treated control (group VI). As carcinogen control, group IV showed the highest tumor volume (8.79±5.44) and tumor burden (3.60±1.17). Comparatively, group III revealed only 20% of tumor incidence, tumor burden (3.00±1.00) and tumor volume (2.40±1.12), which were significantly different from group IV. Group II also showed significant reduction of tumor volume (3.11), tumor burden (3.00) and tumor incidence (11.11%), along with prominent increase of latency period of tumor formation (week 12). Group I, nonetheless, demonstrated marked increment of tumor incidence by 40% with prompted latency period of tumor formation (week 7). No tumor formation was observed in groups V and VI. This study provided clear evidence of inhibitory effects of QRF during promotion period which was in agreement with our previous findings. The mechanism(s) underlying such effects have yet to be elucidated.
  14. Fulltext Isolated Bilateral Pinna Swelling: A Rare Initial Presentation of Leprosy
    Yusuf SYM, Ismail IA, Hamid RA, Jamil NA, Yasin MM
    Open Access Maced J Med Sci, 2019 Jun 15;7(11):1815-1817.
    PMID: 31316665 DOI: 10.3889/oamjms.2019.481
    BACKGROUND: Leprosy or Hansen disease is a chronic infectious disease that causes social stigma due to its deforming bodily appearance and physical disability. It has a wide spectrum of presentation affecting diagnosis.

    CASE REPORT: A 21-year-old man who presented with chronic isolated bilateral pinna swelling as a result of leprosy is reported. The bilateral pinna swelling started as multiple shiny papules with an erythematous background and progressively became hyperpigmented and lobular over two years. This rare presentation of leprosy poses initial diagnostic difficulties, leading to misdiagnoses by various health care professionals. Diagnoses ascribed include eczema, insect bite and perichondritis. A suspicion of leprosy was raised when hyperaesthetic hypopigmentation of skin started to appear on the body after two years, with worsening of the pinna swellings. This was confirmed by identification of Mycobacterium leprae in slit skin smear test and skin biopsy.

    CONCLUSION: Isolated involvement of pinna in a patient without lesions in other body parts is an unusual initial presentation of leprosy. However, leprosy should be kept as a rare differential diagnosis of isolated lesions on the ear in patients not responding to conventional treatment.

  15. Induction of apoptosis on ovarian adenocarcinoma cells, A2780 by tricyclohexylphosphanegold (I) mercaptobenzoate derivatives via intrinsic and extrinsic pathways
    Ang KP, Chan PF, Hamid RA
    J Biol Inorg Chem, 2021 10;26(7):833-853.
    PMID: 34476610 DOI: 10.1007/s00775-021-01892-6
    Tricyclohexylphosphanegold(I) n-mercaptobenzoate (n = 2, 3, 4) labelled as 1-3 were previously reported to significantly suppress thioredoxin reductase (TrxR) activities towards ovarian cancer cells, A2780, in vitro. Herein, we explored the role of 1-3 for their apoptosis inducing ability against A2780 cells. 1-3 exhibited IC50 values at 1.19 ± 0.03 µM, 2.28 ± 0.04 μM and 0.78 ± 0.01 μM, respectively, compared to cisplatin at 26.8 ± 0.15 µM. The compounds induced A2780 apoptosis via a caspase-dependent mitochondrion pathway as evidenced by ROS production, cytochrome c release, caspases-3/7, -8, -9 and -10 activation, APAF1 and BAX upregulation as well as BCL2A1 and BCL2 genes' downregulation. In addition, the death mode of 1-3 was also mediated via death receptor extrinsic pathway manifested by FAS, FASL, FADD, and TNFR1 genes' upregulation via Human Rt PCR analysis. In addition, 1-3 significantly caused A2780 arrest at S phase, which was associated with the upregulation of TP53, E2F1, RB1 and CDKN1A upregulation and downregulation of CDK1, CDK4, CDC25A and CDC25C genes. Based on these promising results, these phosphanegold(I) thiolate derivatives could act as feasible candidates for further advanced in vivo ovarian cancer studies to develop novel chemotherapeutic agents derived from metal-based agents.
  16. Fulltext In vitro antioxidant and antiproliferative activities of methanolic plant part extracts of Theobroma cacao
    Baharum Z, Akim AM, Taufiq-Yap YH, Hamid RA, Kasran R
    Molecules, 2014 Nov 10;19(11):18317-31.
    PMID: 25389662 DOI: 10.3390/molecules191118317
    The aims of this study were to determine the antioxidant and antiproliferative activity of the following Theobroma cacao plant part methanolic extracts: leaf, bark, husk, fermented and unfermented shell, pith, root, and cherelle. Antioxidant activity was determined using 2,2-diphenyl-2-picrylhydrazyl (DPPH), thiobarbituric acid-reactive substances (TBARS), and Folin-Ciocalteu assays; the 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium (MTT) assay was used to determine antiproliferative activity. The root extract had the highest antioxidant activity; its median effective dose (EC50) was 358.3±7.0 µg/mL and total phenolic content was 22.0±1.1 g GAE/100 g extract as compared to the other methanolic plant part extracts. Only the cherelle extract demonstrated 10.4%±1.1% inhibition activity in the lipid peroxidation assay. The MTT assay revealed that the leaf extract had the highest antiproliferative activity against MCF-7 cells [median inhibitory concentration (IC50)=41.4±3.3 µg/mL]. Given the overall high IC50 for the normal liver cell line WRL-68, this study indicates that T. cacao methanolic extracts have a cytotoxic effect in cancer cells, but not in normal cells. Planned future investigations will involve the purification, identification, determination of the mechanisms of action, and molecular assay of T. cacao plant extracts.
  17. Fulltext In vitro Antiproliferative and Apoptosis Inducing Effect of Allium atroviolaceum Bulb Extract on Breast, Cervical, and Liver Cancer Cells
    Khazaei S, Esa NM, Ramachandran V, Hamid RA, Pandurangan AK, Etemad A, et al.
    Front Pharmacol, 2017;8:5.
    PMID: 28197098 DOI: 10.3389/fphar.2017.00005
    Natural products are considered potent sources for novel drug discovery and development. The multiple therapeutic effects of natural compounds in traditional medicine motivate us to evaluate the cytotoxic activity of bulb of Allium atroviolaceum in MCF7 and MDA-MB-231, HeLa and HepG2 cell lines. The bulb methanol extract of A. atroviolaceum was found to be an active cell proliferation inhibitor at the time and dose dependent manner. Determination of DNA content by flow cytometry demonstrated S and G2/M phase arrest of MCF-7 cell, correlated to Cdk1 downregulation, S phase arrest in MDA-MB-231 which is p53 and Cdk1-dependent, sub-G0 cell cycle arrest in HeLa aligned with Cdk1 downregulation, G0/G1, S, G2/M phase arrest in HepG2 which is p53-dependent. Apoptosis as the mechanism of cell death was confirmed by morphology study, caspases activity assay, as well as apoptosis related gene expression, Bcl-2. Caspase-8, -9, and -3 activity with downregulation of Bcl-2 illustrated occurrence of both intrinsic and extrinsic pathways in MCF7, while caspase-3 and -8 activity revealed extrinsic pathway of apoptosis, although Bcl-2 downregulated. In HeLa cells, the activity of caspase-9 and -3 and downregulation of Bcl-2 shows intrinsic pathway or mitochondrial pathway, whereas HepG2 shows caspase independent apoptosis. Further, the combination of the extract with tamoxifen against MCF7 and MDA-MB-231 and combination with doxorubicin against HeLa and HeG2 demonstrated synergistic effect in most concentrations, suggests that the bulb of A. atroviolaceum may be useful for the treatment of cancer lonely or in combination with other drugs.
  18. Fulltext Environmental immune disruptors, inflammation and cancer risk
    Thompson PA, Khatami M, Baglole CJ, Sun J, Harris SA, Moon EY, et al.
    Carcinogenesis, 2015 Jun;36 Suppl 1:S232-53.
    PMID: 26106141 DOI: 10.1093/carcin/bgv038
    An emerging area in environmental toxicology is the role that chemicals and chemical mixtures have on the cells of the human immune system. This is an important area of research that has been most widely pursued in relation to autoimmune diseases and allergy/asthma as opposed to cancer causation. This is despite the well-recognized role that innate and adaptive immunity play as essential factors in tumorigenesis. Here, we review the role that the innate immune cells of inflammatory responses play in tumorigenesis. Focus is placed on the molecules and pathways that have been mechanistically linked with tumor-associated inflammation. Within the context of chemically induced disturbances in immune function as co-factors in carcinogenesis, the evidence linking environmental toxicant exposures with perturbation in the balance between pro- and anti-inflammatory responses is reviewed. Reported effects of bisphenol A, atrazine, phthalates and other common toxicants on molecular and cellular targets involved in tumor-associated inflammation (e.g. cyclooxygenase/prostaglandin E2, nuclear factor kappa B, nitric oxide synthesis, cytokines and chemokines) are presented as example chemically mediated target molecule perturbations relevant to cancer. Commentary on areas of additional research including the need for innovation and integration of systems biology approaches to the study of environmental exposures and cancer causation are presented.
  19. Fulltext Disruptive environmental chemicals and cellular mechanisms that confer resistance to cell death
    Narayanan KB, Ali M, Barclay BJ, Cheng QS, D'Abronzo L, Dornetshuber-Fleiss R, et al.
    Carcinogenesis, 2015 Jun;36 Suppl 1:S89-110.
    PMID: 26106145 DOI: 10.1093/carcin/bgv032
    Cell death is a process of dying within biological cells that are ceasing to function. This process is essential in regulating organism development, tissue homeostasis, and to eliminate cells in the body that are irreparably damaged. In general, dysfunction in normal cellular death is tightly linked to cancer progression. Specifically, the up-regulation of pro-survival factors, including oncogenic factors and antiapoptotic signaling pathways, and the down-regulation of pro-apoptotic factors, including tumor suppressive factors, confers resistance to cell death in tumor cells, which supports the emergence of a fully immortalized cellular phenotype. This review considers the potential relevance of ubiquitous environmental chemical exposures that have been shown to disrupt key pathways and mechanisms associated with this sort of dysfunction. Specifically, bisphenol A, chlorothalonil, dibutyl phthalate, dichlorvos, lindane, linuron, methoxychlor and oxyfluorfen are discussed as prototypical chemical disruptors; as their effects relate to resistance to cell death, as constituents within environmental mixtures and as potential contributors to environmental carcinogenesis.
  20. Fulltext Disruptive chemicals, senescence and immortality
    Carnero A, Blanco-Aparicio C, Kondoh H, Lleonart ME, Martinez-Leal JF, Mondello C, et al.
    Carcinogenesis, 2015 Jun;36 Suppl 1(Suppl 1):S19-37.
    PMID: 26106138 DOI: 10.1093/carcin/bgv029
    Carcinogenesis is thought to be a multistep process, with clonal evolution playing a central role in the process. Clonal evolution involves the repeated 'selection and succession' of rare variant cells that acquire a growth advantage over the remaining cell population through the acquisition of 'driver mutations' enabling a selective advantage in a particular micro-environment. Clonal selection is the driving force behind tumorigenesis and possesses three basic requirements: (i) effective competitive proliferation of the variant clone when compared with its neighboring cells, (ii) acquisition of an indefinite capacity for self-renewal, and (iii) establishment of sufficiently high levels of genetic and epigenetic variability to permit the emergence of rare variants. However, several questions regarding the process of clonal evolution remain. Which cellular processes initiate carcinogenesis in the first place? To what extent are environmental carcinogens responsible for the initiation of clonal evolution? What are the roles of genotoxic and non-genotoxic carcinogens in carcinogenesis? What are the underlying mechanisms responsible for chemical carcinogen-induced cellular immortality? Here, we explore the possible mechanisms of cellular immortalization, the contribution of immortalization to tumorigenesis and the mechanisms by which chemical carcinogens may contribute to these processes.
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