Displaying publications 1 - 20 of 67 in total

  1. Choudhury H, Pandey M, Yin TH, Kaur T, Jia GW, Tan SQL, et al.
    Mater Sci Eng C Mater Biol Appl, 2019 Aug;101:596-613.
    PMID: 31029353 DOI: 10.1016/j.msec.2019.04.005
    Multidrug resistance (MDR) is one of the key barriers in chemotherapy, leading to the generation of insensitive cancer cells towards administered therapy. Genetic and epigenetic alterations of the cells are the consequences of MDR, resulted in drug resistivity, which reflects in impaired delivery of cytotoxic agents to the cancer site. Nanotechnology-based nanocarriers have shown immense shreds of evidence in overcoming these problems, where these promising tools handle desired dosage load of hydrophobic chemotherapeutics to facilitate designing of safe, controlled and effective delivery to specifically at tumor microenvironment. Therefore, encapsulating drugs within the nano-architecture have shown to enhance solubility, bioavailability, drug targeting, where co-administered P-gp inhibitors have additionally combat against developed MDR. Moreover, recent advancement in the stimuli-sensitive delivery of nanocarriers facilitates a tumor-targeted release of the chemotherapeutics to reduce the associated toxicities of chemotherapeutic agents in normal cells. The present article is focused on MDR development strategies in the cancer cell and different nanocarrier-based approaches in circumventing this hurdle to establish an effective therapy against deadliest cancer disease.
    Matched MeSH terms: Drug Resistance, Neoplasm
  2. Kam TS, Sim KM, Koyano T, Toyoshima M, Hayashi M, Komiyama K
    Bioorg. Med. Chem. Lett., 1998 Jul 07;8(13):1693-6.
    PMID: 9873417
    Four new bisindoles of the vobasine-iboga type, conodiparines A-D were obtained from Tabernaemontana corymbosa which showed appreciable activity in reversing resistance in vincristine-resistant KB cells.
    Matched MeSH terms: Drug Resistance, Neoplasm*
  3. Elias MH, Azlan H, Baba AA, Ankathil R
    PMID: 29669505 DOI: 10.2174/1871529X18666180419101416
    BACKGROUND: In exploring the cause of Imatinib Mesylate (IM) resistance among Chronic Myeloid Leukemia (CML) patients who do not harbor BCR-ABL dependent mechanism, BCR-ABL independent pathways are the most probable pathways that should be explored. In BCR-ABL independent pathway, SOCS1 plays an important role as it helps in regulating optimal JAK/STAT activity.

    OBJECTIVE: To identify the association of SOCS1 gene hypermethylation in mediating IM Resistance.

    METHOD: The SOCS1 promoter methylation level of 92 BCR-ABL non mutated IM resistant CML patients, 83 IM good response CML patients and 5 normal samples from healthy individuals were measured using Methylation Specific-High Resolution Melt (MS-HRM) analysis.

    RESULTS: Both primers used to amplify promoter region from -333 to -223 and from -332 to -188 showed less than 10% methylation in all CML and normal samples. Consequently, there was no significant difference in SOCS1 promoter methylation level between IM resistant and IM good response patients.

    CONCLUSION: SOCS1 promoter methylation level is not suitable to be used as one of the biomarkers for predicting the possibility of acquiring resistance among CML patients treated with IM.

    Matched MeSH terms: Drug Resistance, Neoplasm/genetics
  4. Hussain Z, Arooj M, Malik A, Hussain F, Safdar H, Khan S, et al.
    Artif Cells Nanomed Biotechnol, 2018;46(sup2):1015-1024.
    PMID: 29873531 DOI: 10.1080/21691401.2018.1478420
    Development and formulation of an efficient and safe therapeutic regimen for cancer theranostics are dynamically challenging. The use of mono-therapeutic cancer regimen is generally restricted to optimal clinical applications, on account of drug resistance and cancer heterogeneity. Combinatorial treatments can employ multi-therapeutics for synergistic anticancer efficacy whilst reducing the potency of individual moieties and diminishing the incidence of associated adverse effects. The combo-delivery of nanotherapeutics can optimize anti-tumor efficacy while reversing the incidence of drug resistance, aiming to homogenize pharmacological profile of drugs, enhance circulatory time, permit targeted drug accumulation, achieve multi-target dynamic approach, optimize target-specific drug binding and ensure sustained drug release at the target site. Numerous nanomedicines/nanotherapeutics have been developed by having dynamic physicochemical, pharmaceutical and pharmacological implications. These innovative delivery approaches have displayed specialized treatment effects, alone or in combination with conventional anticancer approaches (photodynamic therapy, radiotherapy and gene therapy), while reversing drug resistance and potential off-target effects. The current review presents a comprehensive overview of nanocarrier aided multi-drug therapies alongside recent advancements, future prospects, and the pivotal requirements for interdisciplinary research.
    Matched MeSH terms: Drug Resistance, Neoplasm/drug effects*
  5. Teoh SL, Das S
    Curr. Pharm. Des., 2017;23(12):1845-1859.
    PMID: 28231756 DOI: 10.2174/1381612822666161027120043
    The incidence and mortality due to breast cancer is increasing worldwide. There is a constant quest to know the underlying molecular biology of breast cancer in order to arrive at diagnosis and plan better treatment options. MicroRNAs (miRNAs) are small non-coding and single stranded RNAs which influence the gene expression and physiological condition in any tumor. The miRNAs may act on different pathways in various cancers. Recently, there are research reports on various miRNAs being linked to breast cancers. The important miRNAs associated with breast cancers include miR-21, miR-155, miR-27a, miR-205, miR-145 and miR-320a. In the present review we discuss the role of miRNAs in breast cancer, its importance as diagnostic markers, prognosis and metastasis markers. We also highlight the role of miRNAs with regard to resistance to few anticancerous drugs such as Tamoxifen and Trastuzumab. The role of miRNA in resistance to treatment is one of the core issues discussed in the present review. Much information on the miRNA roles is available particularly in the neoadjuvant chemotherapy setting, because this protocol allows the rapid association of miRNA expression with the treatment response. This review opens the door for designing better therapeutic options in drug resistance cases in breast cancer.
    Matched MeSH terms: Drug Resistance, Neoplasm/genetics*
  6. Khamisipour G, Jadidi-Niaragh F, Jahromi AS, Zandi K, Hojjat-Farsangi M
    Tumour Biol., 2016 Aug;37(8):10021-39.
    PMID: 27155851 DOI: 10.1007/s13277-016-5059-1
    Resistance to chemotherapy agents is a major challenge infront of cancer patient treatment and researchers. It is known that several factors, such as multidrug resistance proteins and ATP-binding cassette families, are cell membrane transporters that can efflux several substrates such as chemotherapy agents from the cell cytoplasm. To reduce the adverse effects of chemotherapy agents, various targeted-based cancer therapy (TBCT) agents have been developed. TBCT has revolutionized cancer treatment, and several agents have shown more specific effects on tumor cells than chemotherapies. Small molecule inhibitors and monoclonal antibodies are specific agents that mostly target tumor cells but have low side effects on normal cells. Although these agents have been very useful for cancer treatment, however, the presence of natural and acquired resistance has blunted the advantages of targeted therapies. Therefore, development of new options might be necessary. A better understanding of tumor cell resistance mechanisms to current treatment agents may provide an appropriate platform for developing and improving new treatment modalities. Therefore, in this review, different mechanisms of tumor cell resistance to chemotherapy drugs and current targeted therapies have been described.
    Matched MeSH terms: Drug Resistance, Neoplasm/drug effects; Drug Resistance, Neoplasm/genetics; Drug Resistance, Neoplasm/physiology*
  7. Lim SZ, Chua EW
    Front Pharmacol, 2018;9:1107.
    PMID: 30349479 DOI: 10.3389/fphar.2018.01107
    Azathioprine and 6-mercaptopurine, often referred to as thiopurine compounds, are commonly used in the management of inflammatory bowel disease. However, patients receiving these drugs are prone to developing adverse drug reactions or therapeutic resistance. Achieving predefined levels of two major thiopurine metabolites, 6-thioguanine nucleotides and 6-methylmercaptopurine, is a long-standing clinical practice in ensuring therapeutic efficacy; however, their correlation with treatment response is sometimes unclear. Various genetic markers have also been used to aid the identification of patients who are thiopurine-sensitive or refractory. The recent discovery of novel Asian-specific DNA variants, namely those in the NUDT15 gene, and their link to thiopurine toxicity, have led clinicians and scientists to revisit the utility of Caucasian biomarkers for Asian individuals with inflammatory bowel disease. In this review, we explore the limitations associated with the current methods used for therapeutic monitoring of thiopurine metabolites and how the recent discovery of ethnicity-specific genetic markers can complement thiopurine metabolites measurement in formulating a strategy for more accurate prediction of thiopurine response. We also discuss the challenges in thiopurine therapy, alongside the current strategies used in patients with reduced thiopurine response. The review is concluded with suggestions for future work aiming at using a more comprehensive approach to optimize the efficacy of thiopurine compounds in inflammatory bowel disease.
    Matched MeSH terms: Drug Resistance, Neoplasm
  8. Aldawsari HM, Gorain B, Alhakamy NA, Md S
    J Drug Target, 2019 Aug 14.
    PMID: 31339380 DOI: 10.1080/1061186X.2019.1648478
    Tumour-associated macrophages (TAMs) represent as much as 50% of the solid mass in different types of human solid tumours including lung, breast, ovarian and pancreatic adenocarcinomas. The tumour microenvironment (TME) plays an important role in the polarisation of macrophages into the M1 phenotype, which is tumour-suppressive, or M2 phenotype, which is tumour promoting. Preclinical and clinical evidences suggest that TAMs are predominantly of the M2 phenotype that supports immune suppression, tumour growth, angiogenesis, metastasis and therapeutic resistance. Hence, significant attention has been focussed on the development of strategies for the modification of TAMs to halt lung cancer progression. The promotion of repolarisation from the M2 to the M1 subtype, or the prevention of M2 polarisation of TAMs in the stromal environment is potential approaches to reduce progression and metastasis of lung cancer. The focus of this article is an introduction to the development and evaluation of therapeutic agents that may halt lung cancer progression via the manipulation of macrophage polarisation. This article will address recent advances in the therapeutic efficacy of nanomedicine exploiting surface functionalisation of nanoparticles and will also consider future perspectives.
    Matched MeSH terms: Drug Resistance, Neoplasm
  9. Abubakar IB, Loh HS
    J. Pharm. Pharmacol., 2016 Apr;68(4):423-32.
    PMID: 26887962 DOI: 10.1111/jphp.12523
    OBJECTIVES: Tabernaemontana is a genus from the plant family, Apocynaceae with vast medicinal application and widespread distribution in the tropics and subtropics of Africa, Americas and Asia. The objective of this study is to critically evaluate the ethnobotany, medicinal uses, pharmacology and phytochemistry of the species, Tabernaemontana corymbosa (Roxb. ex Wall.) and provide information on the potential future application of alkaloids isolated from different parts of the plant.

    KEY FINDINGS: T. corymbosa (Roxb. ex Wall.) parts are used as poultice, boiled juice, decoctions and infusions for treatment against ulceration, fracture, post-natal recovery, syphilis, fever, tumours and orchitis in Malaysia, China, Thailand and Bangladesh. Studies recorded alkaloids as the predominant phytochemicals in addition to phenols, saponins and sterols with vast bioactivities such as antimicrobial, analgesic, anthelmintic, vasorelaxation, antiviral and cytotoxicity.

    SUMMARY: An evaluation of scientific data and traditional medicine revealed the medicinal uses of different parts of T. corymbosa (Roxb. ex Wall.) across Asia. Future studies exploring the structure-bioactivity relationship of alkaloids such as jerantinine and vincamajicine among others could potentially improve the future application towards reversing anticancer drug resistance.

    Matched MeSH terms: Drug Resistance, Neoplasm/drug effects
  10. Fatemian T, Othman I, Chowdhury EH
    Drug Discov. Today, 2014 Jan;19(1):71-8.
    PMID: 23974068 DOI: 10.1016/j.drudis.2013.08.007
    Resistance of cancer cells to anticancer drugs is the main reason for the failure of traditional cancer treatments. Various cellular components and different loops within the signaling pathways contribute to drug resistance which could be modulated with the aim to restore drug efficacy. Unveiling the molecular mechanisms for cancer drug resistance has now paved the way for the development of novel approaches to regulate the response rates to anticancer drugs at the genetic level. The recent progress on identification and validation of the vital genes directly or indirectly involved in development of cancer drug resistance with the aid of the specific knock down ability of RNA interference technology is discussed in this review.
    Matched MeSH terms: Drug Resistance, Neoplasm*
  11. Wong RS, Cheong SK
    Malays J Pathol, 2012 Dec;34(2):77-88.
    PMID: 23424769 MyJurnal
    Although there have been many new developments in the treatment of leukaemia with the use of new anti-leukaemic agents and stem cell transplantation, drug resistance and treatment failure remain a great challenge for the attending physician. Several studies have suggested that leukaemic stem cells (LSCs) play a pivotal role in chemoresistance and metastasis and the mechanisms by which these cells do so have also been elucidated. There is increasing evidence to show that there exists a large pool of therapeutic targets in LSCs and that the eradication of these cells is feasible with some promising results. This article gives an overview of different types of cancer stem cells (CSCs) derived from various types of leukaemia, the mechanisms by which LSCs contribute to drug resistance and metastasis and some recent advances in targeted therapy against LSCs.
    Matched MeSH terms: Drug Resistance, Neoplasm/immunology*
  12. Lim SH, Sim KM, Abdullah Z, Hiraku O, Hayashi M, Komiyama K, et al.
    J. Nat. Prod., 2007 Aug;70(8):1380-3.
    PMID: 17608533
    Four new indole alkaloids were obtained from two Kopsia species, 6-oxoleuconoxine (1) from the leaf extract of K. griffithii and kopsinitarine E (2), kopsijasminine (3), and kopsonoline (4) from the stem-bark extract of K. teoi. The structures of these alkaloids were determined using NMR and MS analysis. Kopsijasminine (3) showed moderate activity in reversing multidrug resistance in vincristine-resistant KB cells.
    Matched MeSH terms: Drug Resistance, Neoplasm/drug effects
  13. Chieng CK, Say YH
    Tumour Biol., 2015 Sep;36(10):8107-20.
    PMID: 25983001 DOI: 10.1007/s13277-015-3530-z
    As the cellular prion protein (PrP(C)) has been implicated in carcinogenesis, we aimed to investigate the effects of cancer cell-specific PrP(C) overexpression from the invasion, metastasis, and apoptosis aspects, by performing cell motility assays, cell proliferation assays under anchorage-dependent and anchorage-independent conditions, and apoptosis evasion when subjected to multiple anti-cancer drugs. Overexpression of PrP(C) in LS 174T was achieved by stable transfection. PrP(C) overexpression was shown to increase cell proliferation in anchorage-dependent and anchorage-independent manners, as shown by more viable cells in 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, more colonies formed in soft agar assay and increased resistance to anoikis in poly-2-hydroxyethyl methacrylate-coated surface. PrP(C) overexpression also increased cell motility and invasiveness of LS 174T. Cell adhesion to extracellular matrix using collagen- and fibronectin-coated surfaces revealed increased cell attachment in LS 174T cells overexpressing PrP(C). Analysis of apoptotic and necrotic cells by propidium iodide/annexin V-fluorescein isothiocyanate microscopy and 7-amino-actinomycin D/annexin V-phycoerythrin flow cytometry revealed that PrP(C) overexpression attenuated doxorubicin-induced apoptosis. Human apoptosis antibody array with 35 apoptosis-related proteins revealed that three inhibitor of apoptosis proteins (IAPs)-survivin, X-linked inhibitor of apoptosis protein (XIAP), and cellular inhibitor of apoptosis protein-1 (cIAP-1)-were upregulated in LS 174T cells overexpressing PrP(C) in doxorubicin-induced apoptosis. In conclusion, the overexpression of PrP(C) could enhance the invasiveness and survival of LS 174T colorectal cancer cells, indicating that PrP(C) plays a role in colorectal cancer biology.
    Matched MeSH terms: Drug Resistance, Neoplasm*
  14. Fatemian T, Chowdhury EH
    Curr Cancer Drug Targets, 2014;14(7):599-609.
    PMID: 25308718
    Malfunctions in membrane transporters or disruptions in signaling cascades induce resistance to chemotherapy in cancer cells resulting in treatment failure. To adjust the genetic alterations leading to these cellular protective measures, dissection and verification of the contributing routes would be required. In justification of knockdown of the key genes, RNA interference provides a reliable probing tool, enabling exploration of phenotypic manifestation of targeted genes. Investigation of the non-transporter targets, predominantly oncogenes and tumor suppressor genes, by means of small interfering RNA with the aim to re-sensitize cancer cells to therapeutics will be discussed in this review.
    Matched MeSH terms: Drug Resistance, Neoplasm*
  15. Tan SJ, Low YY, Choo YM, Abdullah Z, Etoh T, Hayashi M, et al.
    J. Nat. Prod., 2010 Nov 29;73(11):1891-7.
    PMID: 21043460 DOI: 10.1021/np100552b
    A total of 25 alkaloids were isolated from the leaf and stem-bark extracts of Alstonia spatulata, of which five are new alkaloids of the strychnan type (alstolucines A-E, 1-5) and the other, a new alkaloid of the secoangustilobine A type (alstolobine A, 6). The structures of these alkaloids were established using NMR and MS analysis and, in the case of alstolucine B (2), also confirmed by X-ray diffraction analysis. A reinvestigation of the stereochemical assignment of scholaricine (13) by NMR and X-ray analyses indicated that the configuration at C-20 required revision. Alkaloids 1, 2, 6, 7, 9, 10, and 13 reversed multidrug resistance in vincristine-resistant KB cells.
    Matched MeSH terms: Drug Resistance, Neoplasm/drug effects
  16. Ankathil R, Azlan H, Dzarr AA, Baba AA
    Pharmacogenomics, 2018 04;19(5):475-393.
    PMID: 29569526 DOI: 10.2217/pgs-2017-0193
    Despite the excellent efficacy and improved clinical responses obtained with imatinib mesylate (IM), development of resistance in a significant proportion of chronic myeloid leukemia (CML) patients on IM therapy have emerged as a challenging problem in clinical practice. Resistance to imatinib can be due to heterogeneous array of factors involving BCR/ABL-dependent and BCR/ABL-independent pathways. Although BCR/ABL mutation is the major contributory factor for IM resistance, reduced bio-availability of IM in leukemic cells is also an important pharmacokinetic factor that contributes to development of resistance to IM in CML patients. The contribution of polymorphisms of the pharmacogenes in relation to IM disposition and treatment outcomes have been studied by various research groups in numerous population cohorts. However, the conclusions arising from these studies have been highly inconsistent. This review encompasses an updated insight into the impact of pharmacogenetic variability on treatment response of IM in CML patients.
    Matched MeSH terms: Drug Resistance, Neoplasm/genetics
  17. Weiland F, Arentz G, Klingler-Hoffmann M, McCarthy P, Lokman NA, Kaur G, et al.
    J. Proteome Res., 2016 11 04;15(11):4073-4081.
    PMID: 27569743
    Although acetylation is regarded as a common protein modification, a detailed proteome-wide profile of this post-translational modification may reveal important biological insight regarding differential acetylation of individual proteins. Here we optimized a novel peptide IEF fractionation method for use prior to LC-MS/MS analysis to obtain a more in depth coverage of N-terminally acetylated proteins from complex samples. Application of the method to the analysis of the serous ovarian cancer cell line OVCAR-5 identified 344 N-terminally acetylated proteins, 12 of which are previously unreported. The protein peptidyl-prolyl cis-trans isomerase A (PPIA) was detected in both the N-terminally acetylated and unmodified forms and was further analyzed by data-independent acquisition in carboplatin-responsive parental OVCAR-5 cells and carboplatin-resistant OVCAR-5 cells. This revealed a higher ratio of unacetylated to acetylated N-terminal PPIA in the parental compared with the carboplatin-resistant OVCAR-5 cells and a 4.1-fold increase in PPIA abundance overall in the parental cells relative to carboplatin-resistant OVCAR-5 cells (P = 0.015). In summary, the novel IEF peptide fractionation method presented here is robust, reproducible, and can be applied to the profiling of N-terminally acetylated proteins. All mass spectrometry data is available as a ProteomeXchange repository (PXD003547).
    Matched MeSH terms: Drug Resistance, Neoplasm*
  18. Abu N, Hon KW, Jeyaraman S, Jamal R
    Future Oncol, 2018 Dec;14(29):3085-3095.
    PMID: 30468082 DOI: 10.2217/fon-2018-0303
    Since its discovery, cisplatin has become the key drug in chemotherapy for cancers. Nevertheless, chemoresistance in cancers has become an impediment in using cisplatin for cancer treatment. The resistance toward cisplatin is multifaceted as it involves multiple cellular pathways. Ever since the knowledge of long noncoding RNAs as modulators of various molecular pathways came to light, the interest in the biological function of lncRNAs as biomarkers has increased dramatically. Numerous studies have reported the link between the dysregulation of lncRNAs and drug resistance in cancers. More importantly, several lncRNAs were found to be vital in regulating cisplatin resistance. Therefore, this review summarizes the recent efforts in linking between cisplatin resistance and different types of lncRNAs.
    Matched MeSH terms: Drug Resistance, Neoplasm/genetics*
  19. Stebbing J, Shah K, Lit LC, Gagliano T, Ditsiou A, Wang T, et al.
    Oncogene, 2018 06;37(23):3113-3130.
    PMID: 29540829 DOI: 10.1038/s41388-018-0197-0
    Lemur tyrosine kinase 3 (LMTK3) is an oncogenic kinase that is involved in different types of cancer (breast, lung, gastric, colorectal) and biological processes including proliferation, invasion, migration, chromatin remodeling as well as innate and acquired endocrine resistance. However, the role of LMTK3 in response to cytotoxic chemotherapy has not been investigated thus far. Using both 2D and 3D tissue culture models, we found that overexpression of LMTK3 decreased the sensitivity of breast cancer cell lines to cytotoxic (doxorubicin) treatment. In a mouse model we showed that ectopic overexpression of LMTK3 decreases the efficacy of doxorubicin in reducing tumor growth. Interestingly, breast cancer cells overexpressing LMTK3 delayed the generation of double strand breaks (DSBs) after exposure to doxorubicin, as measured by the formation of γH2AX foci. This effect was at least partly mediated by decreased activity of ataxia-telangiectasia mutated kinase (ATM) as indicated by its reduced phosphorylation levels. In addition, our RNA-seq analyses showed that doxorubicin differentially regulated the expression of over 700 genes depending on LMTK3 protein expression levels. Furthermore, these genes were found to promote DNA repair, cell viability and tumorigenesis processes / pathways in LMTK3-overexpressing MCF7 cells. In human cancers, immunohistochemistry staining of LMTK3 in pre- and post-chemotherapy breast tumor pairs from four separate clinical cohorts revealed a significant increase of LMTK3 following both doxorubicin and docetaxel based chemotherapy. In aggregate, our findings show for the first time a contribution of LMTK3 in cytotoxic drug resistance in breast cancer.
    Matched MeSH terms: Drug Resistance, Neoplasm/drug effects; Drug Resistance, Neoplasm/physiology*
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