Interferon-α enhances artemisinin-induced differentiation of HL-60 leukemia cells via a PKCα/ERK pathway

Artemisinin-type drugs for the treatment of hematological malignancies

Qinghaosu, known as artemisinin (ARS), has been for over two millennia, one of the most common herbs prescribed in traditional Chinese medicine (TCM). ARS was developed as an antimalarial drug and currently belongs to the established standard treatments of malaria as a combination therapy worldwide. In addition to the antimalarial bioactivity of ARS, anticancer activities have been shown both in vitro and in vivo. Like other natural products, ARS acts in a multi-specific manner also against hematological malignancies. The chemical structure of ARS is a sesquiterpene lactone, which contains an endoperoxide bridge essential for activity. The main mechanism of action of ARS and its derivatives (artesunate, dihydroartemisinin, artemether) toward leukemia, multiple myeloma, and lymphoma cells comprises oxidative stress response, inhibition of proliferation, induction of various types of cell death as apoptosis, autophagy, ferroptosis, inhibition of angiogenesis, and signal transducers, as NF-κB, MYC, amongst others. Therefore, new pharmaceutically active compounds, dimers, trimers, and hybrid molecules, could enhance the existing therapeutic alternatives in combating hematologic malignancies. Owing to the high potency and good tolerance without side effects of ARS-type drugs, combination therapies with standard chemotherapies could be applied in the future after further clinical trials in hematological malignancies.

Research Progress on Artemisinin and Its Derivatives against Hematological Malignancies

Although current therapeutic methods against hematological malignancies are effective in the early stage, they usually lose their effectiveness because of the development of drug resistances. Seeking new drugs with significant therapeutic effects is one of the current research hotspots. Artemisinin, an extract from the plant Artemisia annua Linne, and its derivatives have excellent antimalarial effects in clinical applications as well as excellent safety. Recent studies have documented that artemisinin and its derivatives (ARTs) also have significant effects against multiple types of tumours, including hematological malignancies. This review focuses on the latest research achievements of ARTs in the treatment of hematological malignancies as well as its mechanisms and future applications. The mechanisms of ARTs against different types of hematological malignancies mainly include cell cycle arrest, induction autophagy and apoptosis, inhibition of angiogenesis, production of reactive oxygen species, and induction of differentiation. Additionally, the review also summarizes the anticancer effects of ARTs in many drug-resistant hematological malignancies and its synergistic effects with other drugs.

Treatment of glioblastoma with herbal medicines

BACKGROUND

In the latest years, a lot of research studies regarding the usage of active agents from plants in the treatment of tumors have been published, but there is no data about successful usage of herbal remedies in the treatment of glioblastoma in humans.

METHODS

The phytotherapy involved five types of herbal medicine which the subjects took in the form of tea, each type once a day at regular intervals. Three patients took herbal medicine along with standard oncological treatment, while two patients applied for phytotherapy after completing medical treatment. The composition of herbal medicine was modified when necessary, which depended on the results of the control scans using the nuclear magnetic resonance technique and/or computed tomography.

RESULTS

Forty-eight months after the introduction of phytotherapy, there were no clinical or radiological signs of the disease, in three patients; in one patient, the tumor was reduced and his condition was stable, and one patient lived for 48 months in spite of a large primary tumor and a massive recurrence, which developed after the treatment had been completed.

CONCLUSIONS

The results achieved in patients in whom tumor regression occurred exclusively through the use of phytotherapy deserve special attention. In order to treat glioblastoma more effectively, it is necessary to develop innovative therapeutic strategies and medicines that should not be limited only to the field of conventional medicine. The results presented in this research paper are encouraging and serve as a good basis for further research on the possibilities of phytotherapy in the treatment of glioblastoma.

Protective effect of artemisinin on chronic alcohol induced-liver damage in mice

The liver disease related to chronic alcohol consumption is one of the leading causes of death for alcoholics. The efficient drug to ameliorate the alcoholic liver injury was needed urgently. The present study was performed to investigate whether artemisinin possessed the protective effect against chronic alcohol consumption. 50 male Kunming mice were divided into 5 groups: control group (C): 10ml/kg saline+10ml/kg saline, alcohol group (A): 10ml/kg 56%(v/v) alcohol+10ml/kg saline, low dose group of artemisinin (L): 10ml/kg 56%(v/v) alcohol+30mg/kg/day artemisinin, medium dose group of artemisinin (M): 10ml/kg 56%(v/v) alcohol+60mg/kg/day artemisinin, high dose group of artemisinin (H): 10ml/kg 56%(v/v) alcohol+120mg/kg/day artemisinin. Drugs were given orally every day. The general state of mice was observed and the levels of serum activities of AST and ALT were detected after treatment with drugs for 30days. Besides, the liver weight index was calculated and histopathological analysis was performed. We successfully demonstrated that treatment with high dose of artemisinin significantly decreased the elevated levels of AST (p<0.05) and ALT (p<0.01) in plasma, as well as the liver weight index (p<0.01). The loss of body weight, tissue injury, oedema and inflammatory cell infiltration in the hepatocytes were found in the A group. These symptoms were remarkably alleviated in animals treated with artemisinin. Artemisinin can inhibit the activation of NF-кB and the expression of inflammatory cytokines inducible nitric oxide synthase. Besides, it can also enhance the stability of liver cell membrane, and reduce the damage of liver cell membrane and liver cell. Artemisinin showed a protective effect against chronic alcohol poisoning and it has a great potential for the clinical application to treat the liver injury induced by alcohol.

Artemisinin protects human retinal pigment epithelial cells from hydrogen peroxide-induced oxidative damage through activation of ERK/CREB signaling

The pathological increase in the levels of reactive oxygen species (ROS) in the retinal pigment epithelium (RPE), is implicated in the development of age-related macular degeneration (AMD). The discovery of drug candidates to effectively protect RPE cells from oxidative damage is required to resolve the pathological aspects and modify the process of AMD. In this study, a FDA-approved anti-malaria drug, Artemisinin was found to suppress hydrogen peroxide (H2O2)-induced cell death in human RPE cell-D407 cells. Further study showed that Artemisinin significantly suppressed H2O2- induced D407 cell death by restoring abnormal changes in nuclear morphology, intracellular ROS, mitochondrial membrane potential and apoptotic biomarkers. Western blotting analysis showed that Artemisinin was able to activate extracellular regulated ERK/CREB survival signaling. Furthermore, Artemisinin failed to suppress H2O2-induced cytotoxicity and the increase of caspase 3/7 activity in the presence of the ERK inhibitor PD98059. Taken together, these results suggest that Artemisinin is a potential protectant with the pro-survival effects against H2O2 insult through activation of the ERK/CREB pathway.

Dihydroartemisinin increases temozolomide efficacy in glioma cells by inducing autophagy

Artemisinin, a powerful antimalarial medicine, is extracted from the Chinese herb, Artemisia annua L., and has the ability to inhibit the proliferation of cancer cells. Dihydroartemisinin (DHA), the major active metabolite of artemisinin, is able to inhibit the growth of a variety of types of human cancer. However, the effect of DHA on human glioma cells remains unclear. The aim of the present study was to investigate the effect of DHA on the proliferation of glioma cells, and whether DHA was able to enhance temozolomide (TMZ) sensitivity in vitro and in vivo. In total, 10 human glioma cell lines were used to analyze the growth inhibition ability of DHA by MTT assay. The typical autophagic vacuoles were monitored by the application of the autofluorescent agent, monodansylcadaverine. Western blotting was used to detect markers of apoptosis and autophagy, namely Caspase-3, Beclin-1 and LC3-B. The combination efficiency of DHA and TMZ was assessed in vitro and in vivo. The half maximal inhibitory concentration (IC₅₀) of DHA differed among the ten human glioma cell lines. The number of autophagic vacuoles was higher in DHA-treated SKMG-4 cells; this was highest of all cell lines analyzed. The expression of autophagy molecular markers, Beclin-1 and LC3-B, was increased following DHA treatment, while no significant alteration was detected in the expression of apoptotic marker Caspase-3. When combined with DHA, the IC₅₀ of TMZ decreased significantly in the four glioma cell lines analyzed. Furthermore, DHA enhanced the tumor inhibition ability of TMZ in tumor-burdened mice. The results of the present study demonstrated that DHA inhibited the proliferation of glioma cells and enhanced the tumor inhibition efficacy of TMZ in vitro and in vivo through the induction of autophagy.

Chlorogenic acid induced apoptosis and inhibition of proliferation in human acute promyelocytic leukemia HL‑60 cells

Chlorogenic acid (CA), is found in high abundance in the leaves of a number of plants and has antibacterial, antiphlogistic, antimutagenic, antioxidant and other biological activities. It reportedly possesses antitumor activity via the induction of apoptosis in chronic myelogenous leukemia (CML) cell lines, including U937 and K562 cells. However, the effects of CA on human acute promyelocytic leukemia (APL) HL‑60 cells remains unknown. In the current study, the ability of CA to cause G0/G1 cycle arrest and induce apoptosis in the treatment of human APL HL‑60 cells was investigated. Following 5 days treatment with 1, 5 and 10 µM CA, cell viability and the effects of CA on the growth of HL‑60 cells were investigated using a growth curve constructed using trypan blue staining. Induction of apoptosis and inhibition of cell proliferation were estimated using Wright's‑Giemsa staining, Hoechst 33342 and propidium iodide (PI) staining, DNA ladder analysis and flow cytometry, following 48 h cell treatment with various doses of CA. The results indicated that the growth of HL‑60 cells reached a plateau phase at 72 h and the proliferation inhibition rate of HL‑60 cells in CA‑treated groups was significantly higher compared with the control, in a time‑ and dose‑dependent manner. However, the level of apoptosis of HL‑60 cells treated with CA markedly increased and formed more apoptotic bodies compared with the cells with no drug treatment, according to the Wright's‑Giemsa staining, Hoechst 33342 and PI staining, respectively. Using DNA ladder analysis and flow cytometry it was shown that a significant characteristic DNA ladder was observed when treated with CA. CA was capable of arresting cell cycle at G0/G1 phase. Apoptosis of HL‑60 cells treated with CA for 48 h was promoted significantly in a dose‑dependent manner, as well as the inhibition of proliferation. The observations revealed that CA inhibits proliferation and induces preprophase apoptosis of HL‑60 cells. Thus, the concentration of 10 µM may be the optimal dose for treatment human acute promyelocytic leukemia.

Interferon alpha and ribavirin collaboratively regulate p38 mitogen-activated protein kinase signaling in hepatoma cells

Signaling events triggered by interferon alpha (IFN-α) and ribavirin are involved in anti-hepatitis C virus (HCV) action. The p38 mitogen-activated protein kinase (MAPK) pathway plays an important role in HCV pathogenesis. Effects of IFN-α and ribavirin on p38 MAPK signaling were investigated in human hepatoma cells. Type I IFN receptor 2 (IFNAR2) mediated IFN-α-induced p38 MAPK phosphorylation. Also, p38 MAPK phosphorylation was enhanced by ribavirin. Treatment for 48 h with a combination of IFN-α and ribavirin increased p38 MAPK phosphorylation, whereas the treatment for 72 h reduced p38 MAPK phosphorylation. Cell culture-derived HCV (HCVcc) infection dramatically increased p38 MAPK phosphorylation and such phosphorylation was inhibited by IFN-α or ribavirin. Moreover, siRNA-mediated knockdown of p38 MAPK resulted in enhancement of ribavirin-dependent HCV RNA replication. These results suggest that regulation of p38 MAPK signaling by IFN-α and ribavirin might contribute to anti-HCV action.

Sesquiterpene lactones as drugs with multiple targets in cancer treatment: focus on parthenolide

Sesquiterpene lactones (SLs) constitute a large and diverse group of biologically active plant compounds that possess anti-inflammatory and antitumor activity. The subclass germacranolides is one of the major groups of SLs. It includes parthenolide, a highly cytotoxic SL that is being tested in clinical trials as an anti-cancer agent. In this review, we focus on SL antitumor activity related to cell-cycle arrest, differentiation, apoptosis induction through the intrinsic pathway, and sensitization of the extrinsic pathway. We also address the regression of tumors in response to cotreatment with conventional chemotherapeutics. We review the nuclear factor-κB-targeted anti-inflammatory activity in vitro and in vivo and relate it to the SL structural features involved in the molecular mechanisms. It is obvious that SLs are emerging as promising anticancer agents, but more investigations are required to fully understand the molecular mechanisms of known SLs in different cell death modalities and how these mechanisms contribute toward the potent antitumor and anti-inflammatory activities of SLs.

Repression of the RHOH gene by JunD

RhoH is a member of the Rho family of small GTP-binding proteins that lacks GTPase activity. Since RhoH is constantly bound by GTP, it is thought to be constitutively active and controlled predominantly by changes in quantitative expression. RhoH is produced specifically in haematopoietic cells and aberrant expression has been linked to various forms of leukaemia. Transcription of the RHOH gene is the first level at which the quantitative levels of the RhoH protein are regulated. Previous studies have demonstrated that RHOH gene transcription is initiated by three distinct promoter regions designated P1, P2 and P3 that define the 5' end of exons 1, 2 and 4 respectively. In the present study we report that the P3 promoter is largely responsible for RHOH gene transcription in the B-lymphocytic cell line Raji. The P3 promoter contains a minimal promoter region and a repressor region extending from -236 to +67 and +68 to +245 respectively, relative to the 5' end of exon 4. Chromatin immunoprecipitation demonstrated that two AP1 (activator protein 1) sites in the minimal promoter region bind JunD. When JUND is overexpressed, the endogenous RHOH gene is repressed; however, when JUND is inhibited, expression of endogenous RHOH is induced both in the Raji cell line and AML (acute myeloid leukaemia) cells. In the HCL (hairy cell leukaemia) cell line JOK-1, induction of RHOH increases expression of the α isoform of protein kinase C. This downstream target of RHOH is also induced in AML cells by JUND inhibition. Collectively, these data indicate that JunD is an inhibitor of RHOH gene expression.

Interferon-α in acute myeloid leukemia: an old drug revisited

Interferon-α (IFN-α), a type I IFN, is a well-known antitumoral agent. The investigation of its clinical properties in acute myeloid leukemia (AML) has been prompted by its pleiotropic antiproliferative and immune effects. So far, integration of IFN-α in the therapeutic arsenal against AML has been modest in view of the divergent results of clinical trials. Recent insights into the key pharmacokinetic determinants of the clinical efficacy of IFN along with advances in its pharmaceutical formulation, have sparked renewed interest in its use. This paper reviews the possible applicability of IFN-α in the treatment of AML and provides a rational basis to re-explore its efficacy in clinical trials.

FOXM1 expression mediates growth suppression during terminal differentiation of HO-1 human metastatic melanoma cells

Induction of terminal differentiation represents a potentially less toxic cancer therapy. Treatment of HO-1 human metastatic melanoma cells with IFN-β plus mezerein (MEZ) promotes terminal differentiation with an irreversible loss of growth potential. During this process, the transcription factor FOXM1 is down-regulated potentially inhibiting transactivation of target genes including those involved in G(2)/M progression and cell proliferation. We investigated the mechanism of FOXM1 down-regulation and its physiological role in terminal differentiation. Genetic and pharmacological studies revealed that FOXM1 down-regulation was primarily caused by MEZ activation of PKCα and co-treatment with IFN-β plus MEZ augmented the effect of PKCα. Promoter analysis with a mutated E-box on the FOXM1 promoter, and in vitro and in vivo binding assays confirm a direct role of c-Myc on FOXM1 expression. Reduction of c-Myc and overexpression of Mad1 by IFN-β plus MEZ treatment should cause potent and persistent reduction of FOXM1 expression during terminal differentiation. Overexpression of FOXM1 restored expression of cell cycle-associated genes and increased the proportion of cells in the S phase. Our experiments support a model for terminal differentiation in which FOXM1 down-regulation via activation of PKCα followed by suppression of c-Myc expression, are causal events in promoting growth inhibition during terminal differentiation.