Methylated chrysin reduced cell proliferation, but antagonized cytotoxicity of other anticancer drugs in acute lymphoblastic leukemia

YM155 and chrysin cooperatively suppress survivin expression in SMARCB1/INI1-deficient tumor cells

SMARCB1/INI1 deficiency is seen in several malignant tumors including malignant rhabdoid tumor (MRT), a highly aggressive pediatric malignancy. Loss of SMARCB1/INI1 function alters diverse oncogenic cellular signals, making it difficult to discover effective targeting therapy. By utilizing an in vitro drug screening system, effective therapeutic agents against SMARCB1/INI1-deficient tumors were explored in this study. In the in vitro drug sensitivity test, 80 agents with various actions were screened for their cytotoxicity in a panel of five SMARCB1/INI1-deficient tumor cell lines. The combination effect was screened based on the Bliss independent model. The growth-inhibitory effect was determined in both the conventional two-dimensional culture and the collagen-embedded three-dimensional culture system. Survivin expression after agent exposure was determined by Western blot analysis. All five cell lines were found to be sensitive to YM155, a selective survivin inhibitor. In the drug combination screening, YM155 showed additive to synergistic effects with various agents including chrysin. Chrysin enhanced YM155-induced apoptosis, but not mitochondrial depolarization upon exposure of SMARCB1/INI1-deficient tumor cells to the two agents for 6 h. YM155 and chrysin synergistically suppressed survivin expression, especially in TTN45 cells in which such suppression was observed as early as 6 h after exposure to the two agents. Survivin is suggested to be a therapeutic target in MRT and other SMARCB1/INI1-deficient tumors. Chrysin, a flavone that is widely distributed in plants, cooperatively suppressed survivin expression and enhanced the cytotoxicity of YM155.

The Anti-Leukemic Activity of Natural Compounds

The use of biologically active compounds has become a realistic option for the treatment of malignant tumors due to their cost-effectiveness and safety. In this review, we aimed to highlight the main natural biocompounds that target leukemic cells, assessed by in vitro and in vivo experiments or clinical studies, in order to explore their therapeutic potential in the treatment of leukemia: acute myeloid leukemia (AML), chronic myeloid leukemia (CML), acute lymphocytic leukemia (ALL), and chronic lymphocytic leukemia (CLL). It provides a basis for researchers and hematologists in improving basic and clinical research on the development of new alternative therapies in the fight against leukemia, a harmful hematological cancer and the leading cause of death among patients.

Emerging cellular and molecular mechanisms underlying anticancer indications of chrysin

Chrysin has been shown to exert several beneficial pharmacological activities. Chrysin has anti-cancer, anti-viral, anti-diabetic, neuroprotective, cardioprotective, hepatoprotective, and renoprotective as well as gastrointestinal, respiratory, reproductive, ocular, and skin protective effects through modulating signaling pathway involved in apoptosis, oxidative stress, and inflammation. In the current review, we discussed the emerging cellular and molecular mechanisms underlying therapeutic indications of chrysin in various cancers. Online databases comprising Scopus, PubMed, Embase, ProQuest, Science Direct, Web of Science, and the search engine Google Scholar were searched for available and eligible research articles. The search was conducted by using MeSH terms and keywords in title, abstract, and keywords. In conclusion, experimental studies indicated that chrysin could ameliorate cancers of the breast, gastrointestinal tract, liver and hepatocytes, bladder, male and female reproductive systems, choroid, respiratory tract, thyroid, skin, eye, brain, blood cells, leukemia, osteoblast, and lymph. However, more studies are needed to enhance the bioavailability of chrysin and evaluate this agent in clinical trial studies.

Aurora B kinase as a therapeutic target in acute lymphoblastic leukemia

PURPOSE

Acute lymphoblastic leukemia (ALL) is curable with standardized chemotherapy. However, the development of novel therapies is still required, especially for patients with relapsed or refractory disease. By utilizing an in vitro drug screening system, active molecular targeting agents against ALL were explored in this study.

METHODS

By the in vitro drug sensitivity test, 81 agents with various actions were screened for their cytotoxicity in a panel of 22 ALL cell lines and ALL clinical samples. The drug effect score (DES) was calculated from the dose-response of each drug for comparison among drugs or samples. Normal peripheral blood mononuclear cells were also applied onto the drug screening to provide the reference control values. The drug combination effect was screened based on the Bliss independent model, and validated by the improved isobologram method.

RESULTS

On sensitivity screening in a cell line panel, barasertib-HQPA which is an active metabolite of barasertib, an aurora B kinase inhibitor, alisertib, an aurora A kinase inhibitor, and YM155, a survivin inhibitor, were effective against the broadest range of ALL cells. The DES of barasertib-HQPA was significantly higher in ALL clinical samples compared to the reference value. There were significant correlations in DES between barasertib-HQPA and vincristine or docetaxel. In the drug combination assay, barasertib-HQPA and eribulin showed additive to synergistic effects.

CONCLUSION

Aurora B kinase was identified to be an active therapeutic target in a broad range of ALL cells. Combination therapy of barasertib and a microtubule-targeting drug is of clinical interest.

Chrysin as an Anti-Cancer Agent Exerts Selective Toxicity by Directly Inhibiting Mitochondrial Complex II and V in CLL B-lymphocytes

We investigated the effect of chrysin on isolated normal and chronic lymphocytic leukemia (CLL) B-lymphocytes and their isolated mitochondria. We report that a selective and significant increase in cytotoxicity, intracellular reactive oxygen species, mitochondrial membrane potential collapse, ADP/ATP ratio, caspase 3 activation and finally apoptosis in chrysin-treated CLL B- lymphocytes. Also we determined that chrysin selectively inhibits complex II and ATPases in cancerous mitochondria. In this study we proved that the ability of chrysin to promote apoptosis in CLL B-lymphocytes performed by selectively targeting of mitochondria. Our findings may provide a potential therapeutic approach for using chrysin to target mitochondria in CLL B-lymphocytes.

Established Human Cell Lines as Models to Study Anti-leukemic Effects of Flavonoids

Despite the extensive work on pathological mechanisms and some recent advances in the treatment of different hematological malignancies, leukemia continues to present a significant challenge being frequently considered as incurable disease. Therefore, the development of novel therapeutic agents with high efficacy and low toxicity is urgently needed to improve the overall survival rate of patients. In this comprehensive review article, the current knowledge about the anticancer activities of flavonoids as plant secondary polyphenolic metabolites in the most commonly used human established leukemia cell lines (HL-60, NB4, KG1a, U937, THP-1, K562, Jurkat, CCRF- CEM, MOLT-3, and MOLT-4) is compiled, revealing clear anti-proliferative, pro-apoptotic, cell cycle arresting, and differentiation inducing effects for certain compounds. Considering the low toxicity of these substances in normal blood cells, the presented data show a great potential of flavonoids to be developed into novel anti-leukemia agents applicable also in the malignant cells resistant to the current conventional chemotherapeutic drugs.

Anticancer potential of the histone deacetylase inhibitor-like effects of flavones, a subclass of polyphenolic compounds: a review

Cancer is characterized by the uncontrolled division of cells, followed by their invasion to other tissues. These kinds of cellular abnormalities arise as a result of the accumulation of genetic mutations or epigenetic alterations. Targeting genetic mutations by drugs is a conventional treatment approach. Nowadays, the development and use of epigenetic drugs are burgeoning, owing to the advancements in epigenetic research. The therapeutic intervention of cancer development by histone deacetylase inhibitors (HDACIs) holds promise for helping to control the disease, but their nonspecific functions impose certain side effects. Therefore, the search for more HDACIs becomes essential. Plentiful literature on the versatility of dietary components including flavones, a class of the flavonoid group, has already established these compounds to be better anticancer agents. The present review focuses on the significance of flavones with regard to their HDACI-mimicking effects as suggested by the recent evidences. The review also proposes an in-depth screening of flavones in future studies, in the hope that flavones may provide a better alternative to synthetic HDACIs.

Selenium-containing chrysin and quercetin derivatives: attractive scaffolds for cancer therapy

Selenium-containing chrysin (SeChry) and 3,7,3',4'-tetramethylquercetin (SePQue) derivatives were synthesized by a microwave-based methodology. In addition to their improvement in terms of DPPH scavenging and potential GPx-like activities, when tested in a panel of cancer cell lines both selenium-derivatives revealed consistently to be more cytotoxic when compared with their oxo and thio-analogues, evidencing the key role of selenocabonyl moiety for these activities. In particular, SeChry elicited a noteworthy cytotoxic activity with mean IC50 values 18- and 3-fold lower than those observed for chrysin and cisplatin, respectively. Additionally, these seleno-derivatives evidenced an ability to overcome cisplatin and multidrug resistance. Notably, a differential behavior toward malignant and nonmalignant cells was observed for SeChry and SePQue, exhibiting higher selectivity indexes when compared with the chalcogen-derivatives and cisplatin. Our preliminary investigation on the mechanism of cytotoxicity of SeChry and SePQue in MCF-7 human mammary cancer cells demonstrated their capacity to efficiently suppress the clonal expansion along with their ability to hamper TrxR activity leading to apoptotic cell death.

Polyphenols as key players for the antileukaemic effects of propolis

Propolis (a bee product) which has a long history of medicinal use by humans has attracted a great deal of research interest in the recent time; this is due to its widely reported biological activities such as antiviral, antifungal, antibacterial, anti-inflammatory, antioxidant, and anticarcinogenic properties. Crude form of propolis and its phenolic contents have both been reported to exhibit antileukaemic effects in various leukaemia cell lines. The ability of the polyphenols found in propolis to arrest cell cycle and induce apoptosis and differentiation in addition to inhibition of cell growth and proliferation makes them promising antileukaemic agents, and hence, they are believed to be a key to the antileukaemic effects of propolis in different types of leukaemia. This paper reviews the molecular bases of antileukaemic activity of both crude propolis and individual polyphenols on various leukaemia cell lines, and it indicates that propolis has the potential to be used in both treatment and prevention of leukaemia. This however needs further evaluation by in vitro, in vivo, and epidemiological studies as well as clinical trials.

Drug targets for cell cycle dysregulators in leukemogenesis: in silico docking studies

Alterations in cell cycle regulating proteins are a key characteristic in neoplastic proliferation of lymphoblast cells in patients with Acute Lymphoblastic Leukemia (ALL). The aim of our study was to investigate whether the routinely administered ALL chemotherapeutic agents would be able to bind and inhibit the key deregulated cell cycle proteins such as - Cyclins E1, D1, D3, A1 and Cyclin Dependent Kinases (CDK) 2 and 6. We used Schrödinger Glide docking protocol to dock the chemotherapeutic drugs such as Doxorubicin and Daunorubicin and others which are not very common including Clofarabine, Nelarabine and Flavopiridol, to the crystal structures of these proteins. We observed that the drugs were able to bind and interact with cyclins E1 and A1 and CDKs 2 and 6 while their docking to cyclins D1 and D3 were not successful. This binding proved favorable to interact with the G1/S cell cycle phase proteins that were examined in this study and may lead to the interruption of the growth of leukemic cells. Our observations therefore suggest that these drugs could be explored for use as inhibitors for these cell cycle proteins. Further, we have also highlighted residues which could be important in the designing of pharmacophores against these cell cycle proteins. This is the first report in understanding the mechanism of action of the drugs targeting these cell cycle proteins in leukemia through the visualization of drug-target binding and molecular docking using computational methods.

A review of molecular mechanisms of the anti-leukemic effects of phenolic compounds in honey

Hematologic malignancies constitute about 9% of all new cases of cancers as reported via the GLOBOCAN series by International Agency for Research on Cancer (IARC) in 2008. So far, the conventional therapeutic and surgical approaches to cancer therapy have not been able to curtail the rising incidence of cancers, including hematological malignancies, worldwide. The last decade has witnessed great research interest in biological activities of phenolic compounds that include anticancer, anti-oxidation and anti-inflammation, among other things. A large number of anticancer agents combat cancer through cell cycle arrest, induction of apoptosis and differentiation, as well as through inhibition of cell growth and proliferation, or a combination of two or more of these mechanisms. Various phenolic compounds from different sources have been reported to be promising anticancer agents by acting through one of these mechanisms. Honey, which has a long history of human consumption both for medicinal and nutritional uses, contains a variety of phenolic compounds such as flavonoids, phenolic acids, coumarins and tannins. This paper presents a review on the molecular mechanisms of the anti-leukemic activity of various phenolic compounds on cell cycle, cell growth and proliferation and apoptosis, and it advocates that more studies should be conducted to determine the potential role of honey in both chemoprevention and chemotherapy in leukemia.