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  1. Fulltext Molecular responses during chemotherapy in acute myeloid leukemias in predicting poor-response to standard chemotherapy
    Maha A, Cheong SK, Leong CF, Seow HF
    Malays J Pathol, 2009 Dec;31(2):81-91.
    PMID: 20514850 MyJurnal
    Signal transduction pathways are constitutively expressed in leukaemic cells resulting in aberrant survival of the cells. It is postulated that in cells of chemo-sensitive patients, chemotherapy induces apoptotic signals leading to cell death while survival signals are maintained in cells of chemo-resistant patients. There is very little information currently, on the expression of these mediators in patients immediately after chemotherapy initiation. We examined the expression pattern of proinflammatory cytokines, signaling molecules of the PI3K and MAPK pathways molecules and death receptor, DR5 on paired samples at diagnosis and during chemotherapy in acute myeloid leukaemia patients treated with cytosine arabinoside and daunorubicin. The results were correlated with remission status one month after chemotherapy. We found that in chemo-sensitive patients, chemotherapy significantly increased the percentage of cases expressing TNF-alpha (p = 0.025, n = 9) and IL-6 (p = 0.002, n = 11) compared to chemo-resistant cases. We also observed an increased percentage of chemo-sensitive cases expressing DR5 and phosphorylated p38, and Jnk. Thus, expression of TNF-alpha, IL-6, DR5, phospho-p38 and phospho-Jnk may regulate cell death in chemo-sensitive cases. In contrast, a significantly higher percentage of chemo-resistant cases expressed phospho-Bad (p = 0.027, n = 9). IL-beta and IL-18 were also found to be higher in chemo-resistant cases at diagnosis and during chemotherapy. Thus, expression of various cellular molecules in leukaemic blasts during chemotherapy may be useful in predicting treatment outcome. These cellular molecules may also be potential targets for alternative therapy.
    Matched MeSH terms: Drug Resistance, Neoplasm/drug effects*
  2. Cytotoxicity of cucurbitacin E from Citrullus colocynthis against multidrug-resistant cancer cells
    Saeed MEM, Boulos JC, Elhaboub G, Rigano D, Saab A, Loizzo MR, et al.
    Phytomedicine, 2019 Sep;62:152945.
    PMID: 31132750 DOI: 10.1016/j.phymed.2019.152945
    BACKGROUND: Cucurbitacin E (CuE) is an oxygenated tetracyclic triterpenoid isolated from the fruits of Citrullus colocynthis (L.) Schrad.

    PURPOSE: This study outlines CuE's cytotoxic activity against drug-resistant tumor cell lines. Three members of ABC transporters superfamily, P-glycoprotein (P-gp), breast cancer resistance protein (BCRP) and ABCB5 were investigated, whose overexpression in tumors is tightly linked to multidrug resistance. Further factors of drug resistance studied were the tumor suppressor TP53 and the epidermal growth factor receptor (EGFR).

    METHODS: Cytotoxicity assays (resazurin assays) were used to investigate the activity of Citrullus colocynthis and CuE towards multidrug resistant cancer cells. Molecular docking (In silico) has been carried out to explore the CuE's mode of binding to ABC transporters (P-gp, BCRP and ABCB5). The visualization of doxorubicin uptake was done by a Spinning Disc Confocal Microscope. The assessment of proteins expression was done by western blotting analysis. COMPARE and hierarchical cluster analyses were applied to identify, which genes correlate with sensitivity or resistance to cucurbitacins (CuA, CuB, CuE, CuD, CuI, and CuK).

    RESULTS: Multidrug-resistant cells overexpressing P-gp or BCRP were cross-resistant to CuE. By contrast, TP53 knock-out cells were sensitive to CuE. Remarkably, resistant cells transfected with oncogenic ΔEGFR or ABCB5 were hypersensitive (collateral sensitive) to CuE. In silico analyses demonstrated that CuE is a substrate for P-gp and BCRP. Immunoblot analyses highlighted that CuE targeted EGFR and silenced its downstream signaling cascades. The most striking result that emerged from the doxorubicin uptake by ABCB5 overexpressing cells is that CuE is an effective inhibitor for ABCB5 transporter when compared with verapamil. The COMPARE analyses of transcriptome-wide expression profiles of tumor cell lines of the NCI identified common genes involved in cell cycle regulation, cellular adhesion and intracellular communication for different cucurbitacins.

    CONCLUSION: CuE represents a potential therapeutic candidate for the treatment of certain types of refractory tumors. To best of our knowledge, this is the first time to identify CuE and verapamil as inhibitors for ABCB5 transporter.

    Matched MeSH terms: Drug Resistance, Neoplasm/drug effects
  3. Chalcones with electron-withdrawing and electron-donating substituents: anticancer activity against TRAIL resistant cancer cells, structure-activity relationship analysis and regulation of apoptotic proteins
    Mai CW, Yaeghoobi M, Abd-Rahman N, Kang YB, Pichika MR
    Eur J Med Chem, 2014 Apr 22;77:378-87.
    PMID: 24675137 DOI: 10.1016/j.ejmech.2014.03.002
    In the present study, a series of 46 chalcones were synthesised and evaluated for antiproliferative activities against the human TRAIL-resistant breast (MCF-7, MDA-MB-231), cervical (HeLa), ovarian (Caov-3), lung (A549), liver (HepG2), colorectal (HT-29), nasopharyngeal (CNE-1), erythromyeloblastoid (K-562) and T-lymphoblastoid (CEM-SS) cancer cells. The chalcone 38 containing an amino (-NH2) group on ring A was the most potent and selective against cancer cells. The effects of the chalcone 38 on regulation of 43 apoptosis-related markers in HT-29 cells were determined. The results showed that 20 apoptotic markers (Bad, Bax, Bcl-2, Bcl-w, Bid, Bim, CD40, Fas, HSP27, IGF-1, IGFBP-4, IGFBP-5, Livin, p21, Survivin, sTNF-R2, TRAIL-R2, XIAP, caspase-3 and caspase-8) were either up regulated or down regulated.
    Matched MeSH terms: Drug Resistance, Neoplasm/drug effects*
  4. Rhazinilam-Leuconolam-Leuconoxine Alkaloids from Leuconotis griffithii
    Gan CY, Low YY, Thomas NF, Kam TS
    J Nat Prod, 2013 May 24;76(5):957-64.
    PMID: 23647487 DOI: 10.1021/np400214y
    Eight new indole alkaloids (1-8) belonging to the rhazinilam-leuconolam-leuconoxine group, in addition to 52 other alkaloids, were isolated from the stem-bark extract of Leuconotis griffithii, viz., nor-rhazinicine (1), 5,21-dihydrorhazinilam-N-oxide (2), 3,14-dehydroleuconolam (3), and leuconodines A-E (4-8). The structures of these alkaloids were determined using NMR and MS analyses and in some instances confirmed by X-ray diffraction analyses. Alkaloids 1, 5, and 7 showed only moderate to weak cytotoxicity toward KB cells (IC50 12-18 μg/mL), while 8 showed moderate activity in reversing MDR in vincristine-resistant KB cells.
    Matched MeSH terms: Drug Resistance, Neoplasm/drug effects
  5. Mechanisms of tumor cell resistance to the current targeted-therapy agents
    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
  6. Fulltext Novel triple‑positive markers identified in human non‑small cell lung cancer cell line with chemotherapy-resistant and putative cancer stem cell characteristics
    Satar NA, Fakiruddin KS, Lim MN, Mok PL, Zakaria N, Fakharuzi NA, et al.
    Oncol Rep, 2018 Aug;40(2):669-681.
    PMID: 29845263 DOI: 10.3892/or.2018.6461
    Through the specific identification and direct targeting of cancer stem cells (CSCs), it is believed that a better treatment efficacy of cancer may be achieved. Hence, the present study aimed to identify a CSC subpopulation from adenocarcinoma cells (A549) as a model of non‑small cell lung cancer (NSCLC). Ιnitially, we sorted two subpopulations known as the triple‑positive (EpCAM+/CD166+/CD44+) and triple‑negative (EpCAM-/CD166-/CD44-) subpopulation using fluorescence-activated cell sorting (FACS). Sorted cells were subsequently evaluated for proliferation and chemotherapy-resistance using a viability assay and were further characterized for their clonal heterogeneity, self-renewal characteristics, cellular migration, alkaline dehydrogenase (ALDH) activity and the expression of stemness-related genes. According to our findings the triple‑positive subpopulation revealed significantly higher (P<0.01) proliferation activity, exhibited better clonogenicity, was mostly comprised of holoclones and had markedly bigger (P<0.001) spheroid formation indicating a better self-renewal capacity. A relatively higher resistance to both 5‑fluouracil and cisplatin with 80% expression of ALDH was observed in the triple‑positive subpopulation, compared to only 67% detected in the triple‑negative subpopulation indicated that high ALDH activity contributed to greater chemotherapy-resistance characteristics. Higher percentage of migrated cells was observed in the triple‑positive subpopulation with 56% cellular migration being detected, compared to only 19% in the triple‑negative subpopulation on day 2. This was similarly observed on day 3 in the triple‑positive subpopulation with 36% higher cellular migration compared to the triple‑negative subpopulation. Consistently, elevated levels of the stem cell genes such as REX1 and SSEA4 were also found in the triple‑positive subpopulation indicating that the subpopulation displayed a strong characteristic of pluripotency. In conclusion, our study revealed that the triple‑positive subpopulation demonstrated similar characteristics to CSCs compared to the triple‑negative subpopulation. It also confirmed the feasibility of using the triple‑positive (EpCAM+/CD166+/CD44+) marker as a novel candidate marker that may lead to the development of novel therapies targeting CSCs of NSCLC.
    Matched MeSH terms: Drug Resistance, Neoplasm/drug effects
  7. Fulltext LMTK3 confers chemo-resistance in breast cancer
    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
  8. Fulltext Mitochondrial DNA alterations may influence the cisplatin responsiveness of oral squamous cell carcinoma
    Aminuddin A, Ng PY, Leong CO, Chua EW
    Sci Rep, 2020 May 12;10(1):7885.
    PMID: 32398775 DOI: 10.1038/s41598-020-64664-3
    Cisplatin is the first-line chemotherapeutic agent for the treatment of oral squamous cell carcinoma (OSCC). However, the intrinsic or acquired resistance against cisplatin remains a major obstacle to treatment efficacy in OSCC. Recently, mitochondrial DNA (mtDNA) alterations have been reported in a variety of cancers. However, the role of mtDNA alterations in OSCC has not been comprehensively studied. In this study, we evaluated the correlation between mtDNA alterations (mtDNA content, point mutations, large-scale deletions, and methylation status) and cisplatin sensitivity using two OSCC cell lines, namely SAS and H103, and stem cell-like tumour spheres derived from SAS. By microarray analysis, we found that the tumour spheres profited from aberrant lipid and glucose metabolism and became resistant to cisplatin. By qPCR analysis, we found that the cells with less mtDNA were less responsive to cisplatin (H103 and the tumour spheres). Based on the findings, we theorised that the metabolic changes in the tumour spheres probably resulted in mtDNA depletion, as the cells suppressed mitochondrial respiration and switched to an alternative mode of energy production, i.e. glycolysis. Then, to ascertain the origin of the variation in mtDNA content, we used MinION, a nanopore sequencer, to sequence the mitochondrial genomes of H103, SAS, and the tumour spheres. We found that the lower cisplatin sensitivity of H103 could have been caused by a constellation of genetic and epigenetic changes in its mitochondrial genome. Future work may look into how changes in mtDNA translate into an impact on cell function and therefore cisplatin response.
    Matched MeSH terms: Drug Resistance, Neoplasm/drug effects*
  9. Aspidofractinine and Eburnane Alkaloids from a North Borneo Kopsia. Ring-Contracted, Additional Ring-Fused, and Paucidactine-Type Aspidofractinine Alkaloids from K. pauciflora
    Yap WS, Gan CY, Sim KS, Lim SH, Low YY, Kam TS
    J Nat Prod, 2016 Jan 22;79(1):230-9.
    PMID: 26717050 DOI: 10.1021/acs.jnatprod.5b00992
    Eleven new indole alkaloids (1-11) comprising seven aspidofractinine and four eburnane alkaloids, were isolated from the stem-bark extract of Kopsia pauciflora occurring in Malaysian Borneo. The aspidofractinine alkaloids include a ring-contracted, an additional ring-fused, a paucidactine regioisomer, two paucidactine, and one kopsine alkaloid. The structures of several of these alkaloids were also confirmed by X-ray diffraction analyses. The bisindole alkaloids isolated, norpleiomutine and kopsoffinol, showed in vitro growth inhibitory activity against human PC-3, HCT-116, MCF-7, and A549 cells and moderate effects in reversing multidrug-resistance in vincristine-resistant human KB cells.
    Matched MeSH terms: Drug Resistance, Neoplasm/drug effects
  10. Corynanthean, eburnan, secoleuconoxine, and pauciflorine alkaloids from Kopsia pauciflora
    Gan CY, Yoganathan K, Sim KS, Low YY, Lim SH, Kam TS
    Phytochemistry, 2014 Dec;108:234-42.
    PMID: 25442910 DOI: 10.1016/j.phytochem.2014.09.014
    Eleven indole alkaloids, comprising four corynanthean, two eburnane, one aspidofractinine, one secoleuconoxine, one andranginine, and two pauciflorine type alkaloids were isolated from the stem-bark and leaf extracts of Kopsia pauciflora. Their structures were determined using NMR and MS analyses. The catharinensine type alkaloid kopsirensine B and the secoleuconoxine alkaloid arboloscine A showed moderate to weak activity in reversing MDR in vincristine-resistant KB cells. The alkaloid content was markedly different compared to that of a sample from Malaysian Borneo.
    Matched MeSH terms: Drug Resistance, Neoplasm/drug effects
  11. Macroline, akuammiline, sarpagine, and ajmaline alkaloids from Alstonia macrophylla
    Lim SH, Low YY, Sinniah SK, Yong KT, Sim KS, Kam TS
    Phytochemistry, 2014 Feb;98:204-15.
    PMID: 24342109 DOI: 10.1016/j.phytochem.2013.11.014
    A total of seventeen alkaloids, comprising six macroline (including alstofolinine A, a macroline indole incorporating a butyrolactone ring-E), two ajmaline, one sarpagine, and eight akuammiline alkaloids, were isolated from the stem-bark and leaf extracts of the Malayan Alstonia macrophylla. The structure and relative configurations of these alkaloids were established using NMR, MS and in several instances, confirmed by X-ray diffraction analysis. Six of these alkaloids were effective in reversing multidrug-resistance (MDR) in vincristine-resistant KB cells.
    Matched MeSH terms: Drug Resistance, Neoplasm/drug effects*
  12. Leucophyllidine, a cytotoxic bisindole alkaloid constituted from the union of an eburnan and a new vinylquinoline alkaloid
    Gan CY, Robinson WT, Etoh T, Hayashi M, Komiyama K, Kam TS
    Org. Lett., 2009 Sep 3;11(17):3962-5.
    PMID: 19708704 DOI: 10.1021/ol9016172
    A cytotoxic bisindole alkaloid possessing an unprecedented structure constituted from the union of an eburnan half and a novel vinylquinoline alkaloid has been isolated from Leuconotis griffithii. The structure was established by analysis of the spectroscopic data and confirmed by X-ray diffraction analysis. A possible biogenetic pathway to the novel quinolinic coupling partner is presented from an Aspidosperma precursor.
    Matched MeSH terms: Drug Resistance, Neoplasm/drug effects
  13. A cycloartane incorporating a fused tetrahydrofuran ring and a cytotoxic lactam from Monocarpia marginalis
    Lim SH, Mahmood K, Komiyama K, Kam TS
    J Nat Prod, 2008 Jun;71(6):1104-6.
    PMID: 18462006 DOI: 10.1021/np800123g
    A new cycloartane, monocarpinine (1), incorporating a fused tetrahydrofuranyl ring, and a cytotoxic tetracyclic lactam, monomarginine (2), were isolated from a stem bark extract of the Malayan species Monocarpia marginalis. The structures of these compounds were determined using NMR and MS analysis. Monomarginine (2) showed appreciable cytotoxicity toward human KB (both drug-sensitive and drug-resistant) and Jurkat cells.
    Matched MeSH terms: Drug Resistance, Neoplasm/drug effects
  14. Biologically active aspidofractinine alkaloids from Kopsia singapurensis
    Subramaniam G, Hiraku O, Hayashi M, Koyano T, Komiyama K, Kam TS
    J Nat Prod, 2008 Jan;71(1):53-7.
    PMID: 18078327
    Ten new indole alkaloids of the aspidofractinine type, in addition to several recently reported indole alkaloids and 20 other known alkaloids, were obtained from the leaf and stem-bark extract of the Malayan Kopsia singapurensis, viz., kopsimalines A-E (1-5), kopsinicine (6), kopsofinone (7), and kopsiloscines H-J (8-10). The structures of these alkaloids were determined using NMR and MS analysis. Kopsimalines A (1), B (2), C (3), D (4), and E (5) and kopsiloscine J (10) were found to reverse multidrug-resistance in vincristine-resistant KB cells, with 1 showing the highest potency.
    Matched MeSH terms: Drug Resistance, Neoplasm/drug effects
  15. Biologically active aspidofractinine, rhazinilam, akuammiline, and vincorine alkaloids from Kopsia
    Subramaniam G, Hiraku O, Hayashi M, Koyano T, Komiyama K, Kam TS
    J Nat Prod, 2007 Nov;70(11):1783-9.
    PMID: 17939738
    Eleven new indole alkaloids, in addition to the previously reported rhazinal (1), and 14 other known alkaloids, were obtained from the Malayan Kopsia singapurensis, viz., kopsiloscines A-F (2-7), 16-epikopsinine (8), kopsilongine- N-oxide (9), 16-epiakuammiline (10), aspidophylline A (11), and vincophylline (12). The structures of these alkaloids were determined using NMR and MS analyses. Rhazinal (1), rhazinilam (17), and rhazinicine (18) showed appreciable cytotoxicity toward drug-sensitive as well as vincristine-resistant KB cells, while kopsiloscines A (2), B (3), and D (5) and aspidophylline A (11) were found to reverse drug-resistance in drug-resistant KB cells.
    Matched MeSH terms: Drug Resistance, Neoplasm/drug effects
  16. Fulltext HOXA4 gene promoter hypermethylation as an epigenetic mechanism mediating resistance to imatinib mesylate in chronic myeloid leukemia patients
    Elias MH, Baba AA, Husin A, Sulong S, Hassan R, Sim GA, et al.
    Biomed Res Int, 2013;2013:129715.
    PMID: 23484077 DOI: 10.1155/2013/129715
    Development of resistance to imatinib mesylate (IM) in chronic myeloid leukemia (CML) patients has emerged as a significant clinical problem. The observation that increased epigenetic silencing of potential tumor suppressor genes correlates with disease progression in some CML patients treated with IM suggests a relationship between epigenetic silencing and resistance development. We hypothesize that promoter hypermethylation of HOXA4 could be an epigenetic mechanism mediating IM resistance in CML patients. Thus a study was undertaken to investigate the promoter hypermethylation status of HOXA4 in CML patients on IM treatment and to determine its role in mediating resistance to IM. Genomic DNA was extracted from peripheral blood samples of 95 CML patients (38 good responders and 57 resistant) and 12 normal controls. All samples were bisulfite treated and analysed by methylation-specific high-resolution melt analysis. Compared to the good responders, the HOXA4 hypermethylation level was significantly higher (P = 0.002) in IM-resistant CML patients. On comparing the risk, HOXA4 hypermethylation was associated with a higher risk for IM resistance (OR 4.658; 95% CI, 1.673-12.971; P = 0.003). Thus, it is reasonable to suggest that promoter hypermethylation of HOXA4 gene could be an epigenetic mechanism mediating IM resistance in CML patients.
    Matched MeSH terms: Drug Resistance, Neoplasm/drug effects*
  17. Fulltext Ravulizumab (ALXN1210) vs eculizumab in adult patients with PNH naive to complement inhibitors: the 301 study
    Lee JW, Sicre de Fontbrune F, Wong Lee Lee L, Pessoa V, Gualandro S, Füreder W, et al.
    Blood, 2019 02 07;133(6):530-539.
    PMID: 30510080 DOI: 10.1182/blood-2018-09-876136
    Ravulizumab (ALXN1210), a new complement C5 inhibitor, provides immediate, complete, and sustained C5 inhibition. This phase 3, open-label study assessed the noninferiority of ravulizumab to eculizumab in complement inhibitor-naive adults with paroxysmal nocturnal hemoglobinuria (PNH). Patients with lactate dehydrogenase (LDH) ≥1.5 times the upper limit of normal and at least 1 PNH symptom were randomized 1:1 to receive ravulizumab or eculizumab for 183 days (N = 246). Coprimary efficacy end points were proportion of patients remaining transfusion-free and LDH normalization. Secondary end points were percent change from baseline in LDH, change from baseline in Functional Assessment of Chronic Illness Therapy (FACIT)-Fatigue score, proportion of patients with breakthrough hemolysis, stabilized hemoglobin, and change in serum free C5. Ravulizumab was noninferior to eculizumab for both coprimary and all key secondary end points (Pinf < .0001): transfusion avoidance (73.6% vs 66.1%; difference of 6.8% [95% confidence interval (CI), -4.66, 18.14]), LDH normalization (53.6% vs 49.4%; odds ratio, 1.19 [0.80, 1.77]), percent reduction in LDH (-76.8% vs -76.0%; difference [95% CI], -0.83% [-5.21, 3.56]), change in FACIT-Fatigue score (7.07 vs 6.40; difference [95% CI], 0.67 [-1.21, 2.55]), breakthrough hemolysis (4.0% vs 10.7%; difference [95% CI], -6.7% [-14.21, 0.18]), and stabilized hemoglobin (68.0% vs 64.5%; difference [95% CI], 2.9 [-8.80, 14.64]). The safety and tolerability of ravulizumab and eculizumab were similar; no meningococcal infections occurred. In conclusion, ravulizumab given every 8 weeks achieved noninferiority compared with eculizumab given every 2 weeks for all efficacy end points, with a similar safety profile. This trial was registered at www.clinicaltrials.gov as #NCT02946463.
    Matched MeSH terms: Drug Resistance, Neoplasm/drug effects*
  18. Fulltext Cytotoxic and radiosensitising effects of a novel thioredoxin reductase inhibitor in breast cancer
    Abdullah NA, Inman M, Moody CJ, Storr SJ, Martin SG
    Invest New Drugs, 2021 10;39(5):1232-1241.
    PMID: 33768386 DOI: 10.1007/s10637-021-01106-5
    Radiotherapy is an effective treatment modality for breast cancer but, unfortunately, not all patients respond fully with a significant number experiencing local recurrences. Overexpression of thioredoxin and thioredoxin reductase has been reported to cause multidrug and radiation resistance - their inhibition may therefore improve therapeutic efficacy. Novel indolequinone compounds have been shown, in pancreatic cancer models, to inhibit thioredoxin reductase activity and exhibit potent anticancer activity. The present study evaluates, using in vitro breast cancer models, the efficacy of a novel indolequinone compound (IQ9) as a single agent and in combination with ionising radiation using a variety of endpoint assays including cell proliferation, clonogenic survival, enzyme activity, and western blotting. Three triple-negative breast cancer (MDA-MB-231, MDA-MB-468, and MDA-MB-436) and two luminal (MCF-7 and T47D) breast cancer cell lines were used. Results show that treatment with IQ9 significantly inhibited thioredoxin reductase activity, and inhibited cell growth and colony formation of breast cancer cells with IC50 values in the low micromolar ranges. Enhanced radiosensitivity of triple-negative breast cancer cells was observed, with sensitiser enhancement ratios of 1.20-1.43, but with no evident radiosensitisation of luminal breast cancer cell lines. IQ9 upregulated protein expression of thioredoxin reductase in luminal but not in triple-negative breast cancer cells which may explain the observed differential radiosensitisation. This study provides important evidence of the roles of the thioredoxin system as an exploitable radiobiological target in breast cancer cells and highlights the potential therapeutic value of indolequinones as radiosensitisers.***This study was not part of a clinical trial. Clinical trial registration number: N/A.
    Matched MeSH terms: Drug Resistance, Neoplasm/drug effects*
  19. Targeted polymeric nanoparticle for anthracycline delivery in hypoxia-induced drug resistance in metastatic breast cancer cells
    Almoustafa HA, Alshawsh MA, Chik Z
    Anticancer Drugs, 2021 Aug 01;32(7):745-754.
    PMID: 33675612 DOI: 10.1097/CAD.0000000000001065
    Poly lactic-co-glycolic acid (PLGA) nanoparticles are intensively studied nanocarriers in drug delivery because of their biodegradability and biochemical characteristics. Polyethylene glycol (PEG) coating for nanocarriers gives them long circulation time in blood and makes them invisible to the reticuloendothelial system. Breast cancer cells have greater uptake of hyaluronic acid compared to normal cells as it binds to their overexpressed CD44 receptors. Since hypoxia plays an important role in cancer metastasis; we formulated PEG-PLGA nanoparticles coated with hyaluronic acid as targeted delivery system for doxorubicin (DOX) using nanoprecipitation method, and characterized them for chemical composition, size, surface charge, shape, and encapsulation efficiency. Then we tested them in vitro on hypoxia-optimized metastatic breast cancer cells. The nanoparticles were spherical with an average size of about 106 ± 53 nm, a negative surface charge (-15 ± 3 mV), and high encapsulation efficiency (73.3 ± 4.1%). In vitro investigation with hypoxia-elevated CD44 MDA-MB-231 cells showed that hyaluronic acid-targeted nanoparticles maintained their efficacy despite hypoxia-induced drug resistance unlike free DOX and nontargeted nanoparticles. In conclusion, this study revealed a simple third generation nanoparticle formulation for targeted treatment of hypoxia-induced drug resistance in breast cancer metastatic cells. Further, optimization is needed including In vivo efficacy and nanoparticle-specific pharmacokinetic studies.
    Matched MeSH terms: Drug Resistance, Neoplasm/drug effects*
  20. Fulltext Down-Regulation of MicroRNA-210 Confers Sensitivity towards 1'S-1'-Acetoxychavicol Acetate (ACA) in Cervical Cancer Cells by Targeting SMAD4
    Phuah NH, Azmi MN, Awang K, Nagoor NH
    Mol Cells, 2017 Apr;40(4):291-298.
    PMID: 28401751 DOI: 10.14348/molcells.2017.2285
    MicroRNAs (miRNAs) are short non-coding RNAs that regulate genes posttranscriptionally. Past studies have reported that miR-210 is up-regulated in many cancers including cervical cancer, and plays a pleiotropic role in carcinogenesis. However, its role in regulating response towards anti-cancer agents has not been fully elucidated. We have previously reported that the natural compound 1'S-1'-acetoxychavicol acetate (ACA) is able to induce cytotoxicity in various cancer cells including cervical cancer cells. Hence, this study aims to investigate the mechanistic role of miR-210 in regulating response towards ACA in cervical cancer cells. In the present study, we found that ACA down-regulated miR-210 expression in cervical cancer cells, and suppression of miR-210 expression enhanced sensitivity towards ACA by inhibiting cell proliferation and promoting apoptosis. Western blot analysis showed increased expression of mothers against decapentaplegic homolog 4 (SMAD4), which was predicted as a target of miR-210 by target prediction programs, following treatment with ACA. Luciferase reporter assay confirmed that miR-210 binds to sequences in 3'UTR of SMAD4. Furthermore, decreased in SMAD4 protein expression was observed when miR-210 was overexpressed. Conversely, SMAD4 protein expression increased when miR-210 expression was suppressed. Lastly, we demonstrated that overexpression of SMAD4 augmented the anti-proliferative and apoptosis-inducing effects of ACA. Taken together, our results demonstrated that down-regulation of miR-210 conferred sensitivity towards ACA in cervical cancer cells by targeting SMAD4. These findings suggest that combination of miRNAs and natural compounds could provide new strategies in treating cervical cancer.
    Matched MeSH terms: Drug Resistance, Neoplasm/drug effects*
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