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  1. In vitro response of human breast cancer cell lines to the growth-inhibitory effects of styrylpyrone derivative (SPD) and assessment of its antiestrogenicity
    Hawariah A, Stanslas J
    Anticancer Res, 1998 Nov-Dec;18(6A):4383-6.
    PMID: 9891496
    Previous studies have shown that a styrylpyrone derivative (SPD) from a local tropical plant had antiprogestin and antiestrogenic effects in early pregnant mice models (Azimahtol et al. 1991). Antiprogestins and antiestrogens can be exploited as a therapeutic approach to breast cancer treatment and thus the antitumor activity of SPD was tested in three different human breast cancer cell lines that is: MCF- 7, T47D and MDA-MB-231, employing, the antiproliferative assay of Lin and Hwang (1991) slightly modified. SPD (10(-10) - 10(-6) M) exhibited strong antiproliferative activity in estrogen and progestin-dependent MCF-7 cells (EC50 = 2.24 x 10(-7) M) and in hormone insensitive MDA-MB-231 (EC50 = 5.62 x 10(-7) M), but caused only partial inhibition of the estrogen- insensitive T47D cells (EC50 = 1.58 x 10(-6) M). However, tamoxifen showed strong inhibition of MCF-7 cells (EC50 = 1.41 x 10(-6) M) and to a lesser extent the T47D cells (EC50 = 2.5 x 10(-6) M) but did not affect the MDA-MB-231 cells. SPD at 1 microM exerted a beffer antiestrogenic activity than 1 microM tamoxifen in suppressing the growth of MCF-7 cells stimulated by 1 nM estradiol. Combined treatment of both SPD and tamoxifen at 1 microM showed additional inhibition on the growth of MCF-7 cells in culture. The antiproliferative properties of SPD are effective on both receptor positive and receptor negative mammary cancer cells, and thus appear to be neither dependent on cellular receptor status nor cellular hormone responses. This enhances in vivo approaches as tumors are heterogenous masses with varying receptor status.
  2. Antagonistic effects of styrylpyrone derivative (SPD) on 7,12-dimethylbenzanthracene-induced rat mammary tumors
    Hawariah A, Stanslas J
    In Vivo, 1998 Jul-Aug;12(4):403-10.
    PMID: 9706492
    Early studies reported that a styrylpyrone derivative (SPD) purified from the Goniothalamus sp. acts as a non-competitive antiestrogen in early pregnant mice (1). In the immature rat uterine wet weight test, we found that SPD markedly reduced uterine weight at doses 1 and 100 mg/kg, thus reflecting negative antiestrogenicity, probably attributed to low binding affinities towards ER. Tamoxifen (Tam) on the other hand exhibited partial antiestrogenicity at all doses (0.01-10 mg/kg BW) and dose-dependent estrogenicity. However, the estrogen antagonism: agonism ratio for SPD is much higher than Tam, which is indicative of the breast cancer antitumor activity as seen in compounds such as MER-25. Pretreatment assessment on 1 mg/kg BW SPD and Tam showed that SPD is not a very good, estrogen antagonist compared to Tam, as it was unable to revert the estrogenicity effect of estradiol benzoate (EB) on immature rat uterine weight. Antitumor activity assessment for SPD exhibited significant tumor growth retardation in 7,12-dimethyl benzanthracene (DMBA) induced rat mammary tumors at all doses employed (2, 10 and 50 mg/kg) compared to the controls (p < 0.01). This compound was found to be more potent than Tam (2 and 10 mg/kg) and displayed greater potency at a dose of 10 mg/kg. It caused complete remission of 33.3% of tumors but failed to prevent onset of new tumors. However, SPD administration at 2 mg/kg caused 16.7% complete remission and partial remission. It also prevented the onset of new tumors throughout the experiment.
  3. Modelling of chromatin morphologies in breast cancer cells undergoing apoptosis using generalized Cauchy field
    Muniandy SV, Stanslas J
    Comput Med Imaging Graph, 2008 Oct;32(7):631-7.
    PMID: 18707844 DOI: 10.1016/j.compmedimag.2008.07.003
    Chromatin morphologies in human breast cancer cells treated with an anti-cancer agent are analyzed at their early stage of programmed cell death or apoptosis. The gray-level images of nuclear chromatin are modelled as random fields. We used two-dimensional isotropic generalized Cauchy field to characterize local self-similarity and global long-range dependence behaviors in the image spatial data. Generalized Cauchy field allows the description of fractal behavior inferred from fractal dimension and the long-range dependence inferred from correlation exponent to be carried out independently. We demonstrated the usefulness of locally self-similar random fields with long-range dependence for modelling chromatin condensation.
  4. Peptide-based and small molecule PD-1 and PD-L1 pharmacological modulators in the treatment of cancer
    Islam MK, Stanslas J
    Pharmacol Ther, 2021 11;227:107870.
    PMID: 33895183 DOI: 10.1016/j.pharmthera.2021.107870
    Cancer immunotherapy is an option to enhance physiological defence mechanism to fight cancer, where natural substances (e.g., antigen/antibody) or small synthetic molecule can be utilized to improve and restore the immune system to stop or slacken the development of malignant cells, stop metastasis and/or help the immune response with synthetic monoclonal antibodies (mAbs) and tumour-agnostic therapy to eliminate cancer cells. Interaction between the programmed cell death ligand 1 (PD-L1) and its receptor (programmed cell death protein 1, PD-1), and cytotoxic T-lymphocyte-associated protein 4 (CTLA4) linked signalling pathways have been identified as perilous towards the body's immune mechanism in regulating the progression of cancer. It is known that certain cancers use these pathways to evade the body's defence mechanism. The immune system is capable of responding to cancer by stalling these trails with specific synthetic antibodies or immune checkpoint inhibitors, which can ultimately either stop or slow cancer cell development. Recent findings and data suggested that using such inhibitors invigorated a new approach to cancer treatment. These inhibitors usually activate the immune system to identify and eliminate cancer cells rather than attacking tumour cells directly. PD-1/PD-L1 inhibitors have already been substantiated for their efficacy in over twenty variations of cancer through different clinical trials. Studies on molecular interaction with existing PD-1/PD-L1 inhibitors that are mainly dominated by antibodies are constantly generating new ideas to develop novel inhibitors. This review has summarised information on reported and/or patented small molecules and peptides for their ability to interact with the PD-1/PD-L1 as a potential anticancer strategy.
  5. Fulltext Analysis of renin-angiotensin aldosterone system gene polymorphisms in Malaysian essential hypertensive and type 2 diabetic subjects
    Ramachandran V, Ismail P, Stanslas J, Shamsudin N
    Cardiovasc Diabetol, 2009;8:11.
    PMID: 19243623 DOI: 10.1186/1475-2840-8-11
    The renin-angiotensin aldosterone system (RAAS) plays an important role in regulating the blood pressure and the genetic polymorphisms of RAAS genes has been extensively studied in relation to the cardiovascular diseases in various populations with conflicting results. The aim of this study was to determine the association of five genetic polymorphisms (A6G and A20C of angiotensinogen (AGT), MboI of renin, Gly460Trp of aldosterone synthase and Lys173Arg of adducin) of RAAS genes in Malaysian essential hypertensive and type 2 diabetic subjects.
  6. Changes in cellular immunity during chemotherapy for primary breast cancer with anthracycline regimens
    Wijayahadi N, Haron MR, Stanslas J, Yusuf Z
    J Chemother, 2007 Dec;19(6):716-23.
    PMID: 18230556
    Anthracyclines are the most widely used anticancer agents for breast cancer, of which doxorubicin and epirubicin have been reported to have equal efficacy. Unfortunately, the integrity of the immune system of breast cancer patients is severely affected by chemotherapy. This study compared the effect of combination chemotherapy with epirubicin (5-fluorouracil, epirubicin, cyclophosphamide (FEC)) and doxorubicin (5-fluorouracil, doxorubicin, cyclophosphamide (FDC)) regimens on subsets of the immune cells of patients with primary malignant breast tumors. Our aim was to determine the best regimen that produces the least degree of myelosuppression. Blood from 80 breast cancer patients undergoing chemotherapy (40 FEC and 40 FDC) was taken before chemotherapy and after every cycle (3 weeks) for 6 cycles. Blood was also taken from 40 normal healthy donors who served as normal control. Subsets of lymphocytes T-helper cells (CD3(+)CD4(+)), T-cytotoxic cells (CD3(+) CD8(+)), B-cells (CD19(+) CD20(+)) and NK cells (CD16(+)/CD56(+)CD3(-)) were analyzed by flow cytometry (FacsCalibur, BD) using monoclonal antibodies (Multitest, BD). All patients in the FEC and FDC groups suffered from myelosuppressive side effects. Both regimens led to an increase in the counts of monocytes but decreased polymorphonuclear cells (PMNs) and lymphocytes. Percentages of T-cytotoxic cells and NK cells were increased, but the percentage of B-cells was dramatically decreased. The phagocytic and intracellular killing ability of PMNs were also suppressed (p<0.01). No significant difference was found between the epirubicin-based regimen and doxorubicin-based regimen with regard to numbers of immune cells, percentages of lymphocytes subsets, Th/CTL ratio, engulfment and killing abilities of PMNs. In conclusion, we found that the epirubicin-based regimen is not superior to the doxorubicin-based regimen with respect to their toxicity of the immune cells, Th/CTL ratio and PMN count and functions. Moreover, both FEC and FDC regimens appear to conserve the cell-mediated immunity response needed for fighting against cancer cells.
  7. Non-steroid receptor-mediated antiproliferative activity of styrylpyrone derivative in human breast cancer cell lines
    Pihie AH, Stanslas J, Din LB
    Anticancer Res, 1998 May-Jun;18(3A):1739-43.
    PMID: 9673398
    The antiproliferative activity of a styrylpyrone derivative (SPD) plant extract, was studied in three different human breast cancer cell lines in culture, and was compared with tamoxifen. The number of living cells was evaluated by Methylene Blue staining technique. SPD showed strong antiproliferative activity in estrogen receptor (ER) and progestin receptor (PgR) positive MCF-7 cells (EC50 = 6.30 x 10(-7) M) and receptor-negative MDA-MB-231 (EC50 = 5.62 x 10(-7) M), but it partially inhibited the high progestin receptor positive T47D cells (EC50 = 1.58 x 10(-6) M). Whereas tamoxifen, a nonsteroidal antiestrogen exhibited strong inhibition on MCF-7 cells (EC50 = 1.41 x 10(-6) M) and partial inhibition on T47D cells (EC50 = 2.5 x 10(-6) M), but did not affect the MDA-MB-231 cells in the concentration range 0.1 nM-1 microM (EC50 = 5.01 microM). At the same concentration range SPD and tamoxifen did not inhibit the proliferation of normal human liver cell line CCL 13 and normal bovine kidney MDBK; whereas adriamycin, a common chemotherapy drug for the treatment of advance cancer, caused 95% inhibition at 10(-6) M. Competitive binding studies showed SPD had no ability to inhibit the binding of [3H]estradiol and [3H]progesterone to ER and PgR, respectively but, tamoxifen exhibited affinity for ER. Therefore, it can be concluded that the antiproliferative activity of SPD was selective towards breast cancer cell lines and not mediated by ER or PgR.
  8. Fulltext Morphological and molecular datasets for Kaempferia species
    Labrooy C, Abdullah TL, Stanslas J
    Data Brief, 2018 Dec;21:1678-1685.
    PMID: 30505900 DOI: 10.1016/j.dib.2018.10.097
    This study compared morphological and molecular data for identification of Kaempferia species. Each species was deposited in Institute of Bioscience (IBS), Universiti Putra Malaysia (UPM) as voucher specimens and ITS sequences of each species deposited in NCBI (https://www.ncbi.nlm.nih.gov/) as GenBank accessions. DNA was extracted using a modified CTAB method and PCR amplification was completed using Internal Transcribed Spacer (ITS4 and ITS5) markers. PCR amplification of products were viewed under gel electrophoresis. Sequencing was performed and sequence characteristics of ITS rDNA in Kaempferia is shown. Qualitative and qualitative scoring of morphological characters and measuring techniques for Kaempferia species are included. In addition, a brief review of molecular markers used in phylogenetic studies of Zingiberaceae is included in this dataset.
  9. Fulltext Influence of N6-Benzyladenine and Sucrose on In Vitro Direct Regeneration and Microrhizome Induction of Kaempferia parviflora Wall. Ex Baker, An Important Ethnomedicinal Herb of Asia
    Labrooy C, Abdullah TL, Stanslas J
    Trop Life Sci Res, 2020 Apr;31(1):123-139.
    PMID: 32963715 DOI: 10.21315/tlsr2020.31.1.8
    Kaempferia parviflora is an ethnomedicinally important plant. Conventional propagation of K. parviflora is hindered by slow growth rate, long dormancy periods and dual use of rhizomes for seeds as well as marketable produce. In our study, we developed a promising dual-phase micropropagation protocol to increase number of plantlets, survivability, biomass and quality plantlets for mass production. Multiple shoot regeneration was found most successful on Murashige and Skoog (MS) media supplemented with 35.52 μM N6-benzyladenine (BA) in terms of highest number of shoots (22.4 ± 1.84), leaves (29.27 ± 1.30), and roots (17.8 ± 1.72) per explant. High survivability was observed with an acclimatisation percentage of 100% in sterile perlite medium. This method was shown to be preferable compared to conventional propagation in terms of propagation time and number of plantlets. Regenerated in vitro plantlets were then successfully induced to form microrhizomes in MS media with an optimal concentration of 6% (w/v) sucrose. Increase in microrhizome biomass (35.7 ± 2.59 g per flask), number of microrhizomes (5.2 ± 0.78), shoots (8.5 ± 1.58) and roots (8.5 ± 1.58) were observed for this treatment. This investigation successfully highlights the manipulation of single factors in short time frame to produce a simple and efficient alternative propagation method for K. parviflora.
  10. Andrographolide inhibits growth of acute promyelocytic leukaemia cells by inducing retinoic acid receptor-independent cell differentiation and apoptosis
    Manikam SD, Manikam ST, Stanslas J
    J Pharm Pharmacol, 2009 Jan;61(1):69-78.
    PMID: 19126299 DOI: 10.1211/jpp/61.01.0010
    The growth inhibiting potential of andrographolide was evaluated in three acute promyelocytic leukaemia cell line models (HL-60, NB4 and all-trans retinoic acid (ATRA)-resistant NB4-R2).
  11. Phytochemicals from Phyllanthus niruri Linn. and their pharmacological properties: a review
    Bagalkotkar G, Sagineedu SR, Saad MS, Stanslas J
    J Pharm Pharmacol, 2006 Dec;58(12):1559-70.
    PMID: 17331318
    This review discusses the medicinal plant Phyllanthus niruri Linn. (Euphorbiaceae), its wide variety of phytochemicals and their pharmacological properties. The active phytochemicals, flavonoids, alkaloids, terpenoids, lignans, polyphenols, tannins, coumarins and saponins, have been identified from various parts of P. niruri. Extracts of this herb have been proven to have therapeutic effects in many clinical studies. Some of the most intriguing therapeutic properties include anti-hepatotoxic, anti-lithic, anti-hypertensive, anti-HIV and anti-hepatitis B. Therefore, studies relating to chemical characteristics and structural properties of the bioactive phytochemicals found in P. niruri are very useful for further research on this plant as many of the phytochemicals have shown preclinical therapeutic efficacies for a wide range of human diseases, including HIV/AIDS and hepatitis B.
  12. Fulltext Pancreatic cancer treatment with targeted therapies: are we there yet?
    Ngozi Nwaefulu O, Rao Sagineedu S, Kaisarul Islam M, Stanslas J
    Eur Rev Med Pharmacol Sci, 2022 Jan;26(2):367-381.
    PMID: 35113412 DOI: 10.26355/eurrev_202201_27861
    OBJECTIVE: Pancreatic cancer (PaCa) is a disease that is extremely difficult to treat and is associated with a high fatality rate. The majority of patients present to hospitals with metastatic or end-stage cancer, making the ultimate cure impossible. End-stage PaCa has no specific treatment, though surgery, irradiation, and chemotherapy can help patients live longer. Consequently, it is vital to accumulate all information on potential targeted therapies for this cancer into a single report.

    MATERIALS AND METHODS: This review has been compiled using relevant keywords and a thorough web search utilising PubMed, ScienceDirect, GoogleScholar, Scopus, MEDLINE, and SpringerLink.

    RESULTS: Conventional medicines that target various biological processes have a significant negative impact on normal cells. As a result, targeted therapies are required, which include the use of small-molecule inhibitors and monoclonal antibodies to target cancer cell surface receptors, growth factors, and other proteins involved in disease progression. In this review, we summarize the known targeted PaCa therapies, which include inhibitors of the KRAS, mTOR, and PI3K/AKT signaling pathways, as well as PARP, hedgehog, EGFR/ErbB, and TGF-β signaling pathways, along with inhibitors of the neurotrophic tropomyosin receptor kinase (NTRK).

    CONCLUSIONS: An adequate understanding of PaCa pathogenesis and the adoption of tailored medicines can increase patients' overall survival. We believe targeted therapy can help patients with PaCa to have a better prognosis. As such, more research is needed to find appropriate biomarkers to aid in early tumor diagnosis and to discover novel prospective therapeutics based on the drugs listed in this article.

  13. Advances in psoriasis research: From pathogenesis to therapeutics
    Sugumaran D, Yong ACH, Stanslas J
    Life Sci, 2024 Oct 15;355:122991.
    PMID: 39153596 DOI: 10.1016/j.lfs.2024.122991
    Psoriasis is a chronic inflammatory condition affecting approximately 2 % to 3 % of the global population. The pathogenesis of psoriasis is complex, involving immune dysregulation, hyperproliferation and angiogenesis. It is a multifactorial disease which is influenced by genetic and environmental factors. The development of various therapeutic agents, such as JAK inhibitors, small molecules, and biologics with potential anti-psoriatic properties was possible with the vast understanding of the pathogenesis of psoriasis. Various signalling pathways, including NF-κB, JAK-STAT, S1P, PDE-4, and A3AR that are involved in the pathogenesis of psoriasis as well as the preclinical models utilised in the research of psoriasis have been highlighted in this review. The review also focuses on technological advancements that have contributed to a better understanding of psoriasis. Then, the molecules targeting the respective signalling pathways that are still under clinical trials or recently approved as well as the latest breakthroughs in therapeutic and drug delivery approaches that can contribute to the improvement in the management of psoriasis are highlighted in this review. This review provides an extensive understanding of the current state of research in psoriasis, giving rise to opportunities for researchers to discover future therapeutic breakthroughs and personalised interventions. Efficient treatment options for individuals with psoriasis can be achieved by an extensive understanding of pathogenesis, therapeutic agents, and novel drug delivery strategies.
  14. Fulltext Encephalitis followed by optic neuritis: a case report and review of literature
    Hasan S, B Basri H, P Hin L, Stanslas J
    Pak J Med Sci, 2013 May;29(3):859-62.
    PMID: 24353644
    Encephalitis has been included in the causes of optic neuritis, but post encephalitic optic neuritis has been rarely reported. Majority of the cases of optic neuritis are either idiopathic or associated with multiple sclerosis, especially in western countries. This is very important in the Asian population where the incidence and prevalence of multiple sclerosis is not as high as in the Western countries. Although post infectious optic neuritis is more common in children, it can also be found in adults and is usually seen one to three weeks after a symptomatic infective prodrome. Here, we present a case of a 48 year-old-male who developed optic neuritis following viral encephalitis. His first presentation was with severe headache of two weeks duration. Viral encephalitis was diagnosed and treated. The patient presented again three weeks later with right eye pain and other features typical of optic neuritis. Corticosteroid therapy facilitated prompt recovery. Optic neuritis is an uncommon manifestation of encephalitis. It is important that both doctors and patients remain aware of post infectious cause of optic neuritis, which would enable a timely diagnosis and treatment of this reversible cause of vision loss.
  15. Genetic polymorphisms and drug interactions leading to clopidogrel resistance: why the Asian population requires special attention
    Hasan MS, Basri HB, Hin LP, Stanslas J
    Int J Neurosci, 2013 Mar;123(3):143-54.
    PMID: 23110469 DOI: 10.3109/00207454.2012.744308
    Ischemic heart disease and stroke are the two leading causes of death worldwide. Antiplatelet therapy plays the most significant role in the management of these cardiovascular and cerebrovascular occlusive events to prevent recurrent ischemic attack. Clopidogrel, an antiplatelet drug, is widely prescribed either alone or in combination with aspirin as dual antiplatelet therapy for the prevention of vascular occlusive events. The antiplatelet response to clopidogrel varies widely. Hyporesponders and nonresponders are likely to have adverse cardiovascular events during follow-up. Some drugs, such as proton pump inhibitors (omeprazole), calcium channel blockers, selective serotonin reuptake inhibitors (nefazadone), coumarin derivatives (phenprocoumon), benzodiazepines, sulfonylurea, erythromycin, and itraconazole, decrease the antiplatelet effect of clopidogrel when administered concomitantly. Decreased response to clopidogrel is common among Asians due to genetic polymorphisms associated with clopidogrel resistance, and it is nearly 70% in some of the Asian communities. It is necessary to study Asian populations, because there are a large number of Asians throughout the world due to increased migration. Current guidelines do not make genetic testing or platelet response testing mandatory prior to clopidogrel prescription. Therefore, it is important for clinicians treating Asian patients to keep in mind the interindividual variability in response to clopidogrel when prescribing the drug.
  16. A young lady with thalamic stroke mimicking acute Miller Fisher syndrome
    Hasan S, Stanslas J, Hin LP, Basri HB
    Neurosciences (Riyadh), 2012 Oct;17(4):380-1.
    PMID: 23022907
  17. Efficiency of different Agrobacterium rhizogenes strains on hairy roots induction in Solanum mammosum
    Ooi CT, Syahida A, Stanslas J, Maziah M
    World J Microbiol Biotechnol, 2013 Mar;29(3):421-30.
    PMID: 23090845 DOI: 10.1007/s11274-012-1194-z
    This article presents the abilities and efficiencies of five different strains of Agrobacterium rhizogenes (strain ATCC 31798, ATCC 43057, AR12, A4 and A13) to induce hairy roots on Solanum mammosum through genetic transformation. There is significant difference in the transformation efficiency (average number of days of hairy root induction) and transformation frequency for all strains of A. rhizogenes (P < 0.05). Both A. rhizogenes strain AR12 and A13 were able to induce hairy root at 6 days of co-cultivation, which were the fastest among those tested. However, the transformation frequencies of all five strains were below 30 %, with A. rhizogenes strain A4 and A13 showing the highest, which were 21.41 ± 10.60 % and 21.43 ± 8.13 % respectively. Subsequently, the cultures for five different hairy root lines generated by five different strains of bacteria were established. However, different hairy root lines showed different growth index under the same culture condition, with the hairy root lines induced by A. rhizogenes strain ATCC 31798 exhibited largest increase in fresh biomass at 45 days of culture under 16 h light/8 h dark photoperiod in half-strength MS medium. The slowest growing hairy root line, which was previously induced by A. rhizogenes strain A13, when cultured in optimized half-strength MS medium containing 1.5 times the standard amount of ammonium nitrate and potassium nitrate and 5 % (w/v) sucrose, had exhibited improvement in growth index, that is, the fresh biomass was almost double as compared to its initial growth in unmodified half-strength MS medium.
  18. Naturally occurring labdane diterpene and benzofuran from Globba pendula
    Maulidiani, Shaari K, Paetz C, Stanslas J, Abas F, Lajis NH
    Nat Prod Commun, 2009 Aug;4(8):1031-6.
    PMID: 19768978
    Phytochemical investigation on Globba pendula resulted in the isolation of a new naturally occurring 16-oxo-(8)17-12-labdadien-15,11-olide 1 and benzofuran-2-carboxaldehyde 2. Other known compounds including isoandrographolide, indirubin, vanillin, vanillic acid, 2(3H)-benzoxazolone, as well as beta-sitosteryl-beta-D-glucopyranoside, beta-sitosterol, and 7alpha-hydroxysitosterol were also isolated. The structures were established based on spectroscopic data and comparison with the literature. Furthermore, the compound isoandrographolide has demonstrated strong cytotoxic properties towards a panel of cancer cell lines (MCF-7, PC-3, and H-460) with the IC50 values of 7.9, 8.7, and 9.0 microM, respectively.
  19. Pharmacological modulation of oncogenic Ras by natural products and their derivatives: Renewed hope in the discovery of novel anti-Ras drugs
    Quah SY, Tan MS, Teh YH, Stanslas J
    Pharmacol Ther, 2016 06;162:35-57.
    PMID: 27016467 DOI: 10.1016/j.pharmthera.2016.03.010
    Oncogenic rat sarcoma (Ras) is linked to the most fatal cancers such as those of the pancreas, colon, and lung. Decades of research to discover an efficacious drug that can block oncogenic Ras signaling have yielded disappointing results; thus, Ras was considered "undruggable" until recently. Inhibitors that directly target Ras by binding to previously undiscovered pockets have been recently identified. Some of these molecules are either isolated from natural products or derived from natural compounds. In this review, we described the potential of these compounds and other inhibitors of Ras signaling in drugging Ras. We highlighted the modes of action of these compounds in suppressing signaling pathways activated by oncogenic Ras, such as mitogen-activated protein kinase (MAPK) signaling and the phosphoinositide-3-kinase (PI3K) pathways. The anti-Ras strategy of these compounds can be categorized into four main types: inhibition of Ras-effector interaction, interference of Ras membrane association, prevention of Ras-guanosine triphosphate (GTP) formation, and downregulation of Ras proteins. Another promising strategy that must be validated experimentally is enhancement of the intrinsic Ras-guanosine triphosphatase (GTPase) activity by small chemical entities. Among the inhibitors of Ras signaling that were reported thus far, salirasib and TLN-4601 have been tested for their clinical efficacy. Although both compounds passed phase I trials, they failed in their respective phase II trials. Therefore, new compounds of natural origin with relevant clinical activity against Ras-driven malignancies are urgently needed. Apart from salirasib and TLN-4601, some other compounds with a proven inhibitory effect on Ras signaling include derivatives of salirasib, sulindac, polyamine, andrographolide, lipstatin, levoglucosenone, rasfonin, and quercetin.
  20. Fulltext Cytotoxic Properties and Complete Nuclear Magnetic Resonance Assignment of Isolated Xanthones from the Root of Garcinia cowa Roxb
    Wahyuni FS, Shaari K, Stanslas J, Lajis NH, Hamidi D
    Pharmacogn Mag, 2016 Jan;12(Suppl 1):S52-6.
    PMID: 27041859 DOI: 10.4103/0973-1296.176115
    To isolate compounds from the roots of Garcinia cowa and to evaluated their cytotoxic activity against breast (MCF-7), prostate (DU-145), and lung (H-460) cell lines.
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