Fullerene derivative prevents cellular transformation induced by JAK2 V617F mutant through inhibiting c-Jun N-terminal kinase pathway

Fullerenes for the treatment of cancer: an emerging tool

Cancer is a most common cause of mortality globally. Available medicines possess severe side effects owing to their non-specific targeting. Hence, there is a need of an alternative in the healthcare system that should have high efficacy with the least side effects, also having the ability to achieve site-specific targeting and be reproducible. This is possible with the help of fullerenes. Fullerenes are having the unique physicochemical and photosensitizer properties. This article discusses the synthesis, functionalization, mechanism, various properties, and applications of C60 fullerenes in the treatment of cancer. The review article also addresses the various factors influencing the activity of fullerenes including the environmental conditions, toxicity profile, and future prospective.

[Development of Bio-active Fullerene Derivatives Suitable for Drug]

Fullerene (C₆₀) and fullerene derivatives are attractive novel compounds not only for carbon materials of nanotechnology but also for medical fields because of its unique chemical and physical properties. We intend to develop fullerene derivatives as novel lead compounds for drug discovery. At first, we synthesized many types of water-soluble fullerene derivatives to investigate their biological activities because of their poor solubility in water. We found that anionic fullerene derivatives possess anti-oxidant activities, whereas di-cationic fullerene derivatives exhibited antiproliferative activities against various cancer cell lines including drug-resistant cells. Proline-type fullerene derivatives showed inhibitory activities against human immunodeficiency virus (HIV) reverse transcriptase, HIV protease, hepatitis C virus (HCV) NS5B RNA polymerase, and HCV NS3/4A protease. These activities may strongly inhibit virus replication via a synergistic effect and fullerene derivatives may be used as novel multi-target drugs for the treatment of AIDS and hepatitis C in the future.

Novel Mechanism by a Bis-Pyridinium Fullerene Derivative to Induce Apoptosis by Enhancing the MEK-ERK Pathway in a Reactive Oxygen Species-Independent Manner in BCR-ABL-Positive Chronic Myeloid Leukemia-Derived K562 Cells

In the treatment of breakpoint cluster region-Abelson (BCR-ABL)-positive chronic myeloid leukemia (CML) using BCR-ABL inhibitors, the appearance of a gatekeeper mutation (T315I) in BCR-ABL is a serious issue. Therefore, the development of novel drugs that overcome acquired resistance to BCR-ABL inhibitors by CML cells is required. We previously demonstrated that a bis-pyridinium fullerene derivative (BPF) induced apoptosis in human chronic myeloid leukemia (CML)-derived K562 cells partially through the generation of reactive oxygen species (ROS). We herein show that BPF enhanced the activation of the mitogen-activated protein kinase/extracellular signal-regulated kinase kinase-extracellular signal-regulated kinase (MEK-ERK) pathway in a ROS-independent manner. BPF-induced apoptosis was attenuated by trametinib, suggesting the functional involvement of the MEK-ERK pathway in apoptosis in K562 cells. In addition, the constitutive activation of the MEK-ERK pathway by the enforced expression of the BRAFV600E mutant significantly increased the sensitivity of K562 cells to BPF. These results confirmed for the first time that BPF induces apoptosis in K562 cells through dual pathways-ROS production and the activation of the MEK-ERK pathway. Furthermore, BPF induced cell death in transformed Ba/F3 cells expressing not only BCR-ABL but also T315I mutant through the activation of the MEK-ERK pathway. These results indicate that BPF is as an effective CML drug that overcomes resistance to BCR-ABL inhibitors.

A bis-pyridinium fullerene derivative induces apoptosis through the generation of ROS in BCR-ABL-positive leukemia cells

A fusion protein, Breakpoint cluster region-Abelson (BCR-ABL) is responsible for the development of chronic myeloid leukemia (CML) and acute lymphocytic leukemia (ALL). Inhibitors against BCR-ABL are effective for the treatment of leukemia; however, a gatekeeper mutation (T315I) in BCR-ABL results in resistance to these inhibitors, which markedly impedes their efficacy. We herein demonstrated that a bis-pyridinium fullerene derivative (BPF) significantly induced apoptosis in human CML-derived K562 cells and ALL-derived SUP-B15 cells via the generation of reactive oxygen species (ROS). BPF reduced the expression of Bcr-Abl mRNA by inhibiting expression of c-Myc through ROS production. BPF also accelerated protein degradation of BCR-ABL through ROS production. Furthermore, BPF down-regulated the expression of not only BCR-ABL but also T315I-mutated BCR-ABL in ROS-dependent manner. As a result, BPF effectively induced apoptosis in transformed Ba/F3 cells expressing both BCR-ABL and T315I-mutated BCR-ABL. Collectively, these results indicate the potential of BPF as an effective leukemia drug that overcomes resistance to BCR-ABL inhibitors.

Effects of Aqueous Dispersions of C60, C70 and Gd@C82 Fullerenes on Genes Involved in Oxidative Stress and Anti-Inflammatory Pathways

Background: Fullerenes and metallofullerenes can be considered promising nanopharmaceuticals themselves and as a basis for chemical modification. As reactive oxygen species homeostasis plays a vital role in cells, the study of their effect on genes involved in oxidative stress and anti-inflammatory responses are of particular importance. Methods: Human fetal lung fibroblasts were incubated with aqueous dispersions of C₆₀, C₇₀, and Gd@C₈₂ in concentrations of 5 nM and 1.5 µM for 1, 3, 24, and 72 h. Cell viability, intracellular ROS, NOX4, NFκB, PRAR-γ, NRF2, heme oxygenase 1, and NAD(P)H quinone dehydrogenase 1 expression have been studied. Results & conclusion: The aqueous dispersions of C₆₀, C₇₀, and Gd@C₈₂ fullerenes are active participants in reactive oxygen species (ROS) homeostasis. Low and high concentrations of aqueous fullerene dispersions (AFD) have similar effects. C₇₀ was the most inert substance, C₆₀ was the most active substance. All AFDs have both “prooxidant” and “antioxidant” effects but with a different balance. Gd@C₈₂ was a substance with more pronounced antioxidant and anti-inflammatory properties, while C₇₀ had more pronounced “prooxidant” properties.

Antitumor Activity and Potential Mechanism of Novel Fullerene Derivative Nanoparticles

The development of novel nanoparticles as a new generation therapeutic drug platform is an active field of chemistry and cancer research. In recent years, fullerene nanoparticles have received extensive attention due to their unique physical and chemical properties. Properly modified fullerene nanoparticles have excellent biocompatibility and significant anti-tumor activity, which makes them have broad application prospects in the field of cancer therapy. Therefore, understanding the anti-tumor mechanism of fullerene nanoparticles is of great significance for the design and development of anti-tumor drugs with low toxicity and high targeting. This review has focused on various anti-tumor mechanisms of fullerene derivatives and discusses their toxicity and their distribution in organisms. Finally, the review points out some urgent problems that need solution before fullerene derivatives as a new generation of anti-tumor nano-drug platform enter clinical research.

Erythropoietin regulation of red blood cell production: from bench to bedside and back

More than 50 years of efforts to identify the major cytokine responsible for red blood cell (RBC) production (erythropoiesis) led to the identification of erythropoietin (EPO) in 1977 and its receptor (EPOR) in 1989, followed by three decades of rich scientific discovery. We now know that an elaborate oxygen-sensing mechanism regulates the production of EPO, which in turn promotes the maturation and survival of erythroid progenitors. Engagement of the EPOR by EPO activates three interconnected signaling pathways that drive RBC production via diverse downstream effectors and simultaneously trigger negative feedback loops to suppress signaling activity. Together, the finely tuned mechanisms that drive endogenous EPO production and facilitate its downstream activities have evolved to maintain RBC levels in a narrow physiological range and to respond rapidly to erythropoietic stresses such as hypoxia or blood loss. Examination of these pathways has elucidated the genetics of numerous inherited and acquired disorders associated with deficient or excessive RBC production and generated valuable drugs to treat anemia, including recombinant human EPO and more recently the prolyl hydroxylase inhibitors, which act partly by stimulating endogenous EPO synthesis. Ongoing structure-function studies of the EPOR and its essential partner, tyrosine kinase JAK2, suggest that it may be possible to generate new "designer" drugs that control selected subsets of cytokine receptor activities for therapeutic manipulation of hematopoiesis and treatment of blood cancers.

A major component of vitamin E, α-tocopherol inhibits the anti-tumor activity of crizotinib against cells transformed by EML4-ALK

Crizotinib is an inhibitor of anaplastic lymphoma kinase (ALK) and is of significant therapeutic benefit to patients with non-small cell lung cancer (NSCLC) harboring the EML4-ALK fusion gene. In the present study, we demonstrated that α-tocopherol, a major component of vitamin E, attenuated the effects of crizotinib independently of its anti-oxidant properties. α-Tocopherol significantly inhibited crizotinib-induced apoptosis in cells transformed by EML4-ALK. It also effectively attenuated the crizotinib-induced inhibition of EML4-ALK and its downstream molecules, STAT3 and ERK, and suppressed the inhibitory effects of crizotinib on EML4-ALK-mediated transformation in the focus formation assay. On the other hand, other members of the vitamin E family, namely, β-tocopherol, γ-tocopherol, δ-tocopherol, and α-tocotrienol, and a water-soluble analog of vitamin E, Trolox had no effects on the anti-tumor activity of crizotinib in cells transformed by EML4-ALK. Collectively, these results revealed the risk of the anti-tumor activity of crizotinib being attenuated when it is administrated in combination with vitamin E supplements containing α-tocopherol as a major component.

A bis-malonic acid fullerene derivative significantly suppressed IL-33-induced IL-6 expression by inhibiting NF-κB activation

IL-33 functions as a ligand for ST2L, which is mainly expressed in immune cells, including mast cells. IL-33 is a potent inducer of pro-inflammatory cytokines, such as IL-6, and has been implicated in the pathogenesis of allergic inflammatory diseases. Therefore, IL-33 has recently been attracting attention as a new target for the treatment of inflammatory diseases. In the present study, we demonstrated that a water-soluble bis-malonic acid fullerene derivative (C₆₀-dicyclopropane-1,1,1',1'-tetracarboxylic acid) markedly diminished the IL-33-induced expression of IL-6 in bone marrow-derived mast cells (BMMC). The bis-malonic acid fullerene derivative suppressed the canonical signaling steps required for NF-κB activation such as the degradation of IκBα and nuclear translocation of NF-κB by directly inhibiting the IL-33-induced IKK activation. Although p38 and JNK also contributed to IL-33-induced expression of IL-6, the bis-malonic acid fullerene derivative did not affect their activation. Furthermore, the bis-malonic acid fullerene derivative had no effect on the NF-κB activation pathway induced by TNFα and IL-1. These results suggest that the bis-malonic fullerene derivative has potential as a specific drug for the treatment of IL-33-induced inflammatory diseases by specifically inhibiting the NF-κB activation pathway.

c-Jun N-terminal Kinase (JNK) Signaling as a Therapeutic Target for Alzheimer's Disease

c-Jun N-terminal kinases (JNKs) are a family of protein kinases that play a central role in stress signaling pathways implicated in gene expression, neuronal plasticity, regeneration, cell death, and regulation of cellular senescence. It has been shown that there is a JNK pathway activation after exposure to different stressing factors, including cytokines, growth factors, oxidative stress, unfolded protein response signals or Aβ peptides. Altogether, JNKs have become a focus of screening strategies searching for new therapeutic approaches to diabetes, cancer or liver diseases. In addition, activation of JNK has been identified as a key element responsible for the regulation of apoptosis signals and therefore, it is critical for pathological cell death associated with neurodegenerative diseases and, among them, with Alzheimer’s disease (AD). In addition, in vitro and in vivo studies have reported alterations of JNK pathways potentially associated with pathogenesis and neuronal death in AD. JNK’s, particularly JNK3, not only enhance Aβ production, moreover it plays a key role in the maturation and development of neurofibrillary tangles. This review aims to explain the rationale behind testing therapies based on inhibition of JNK signaling for AD in terms of current knowledge about the pathophysiology of the disease. Keeping in mind that JNK3 is specifically expressed in the brain and activated by stress-stimuli, it is possible to hypothesize that inhibition of JNK3 might be considered as a potential target for treating neurodegenerative mechanisms associated with AD.

A proline-type fullerene derivative inhibits adipogenesis by preventing PPARγ activation

Obesity and its associated metabolic diseases represent some of the most rapidly expanding health issues worldwide, and, thus, the development of a novel chemical compound to suppress adipogenesis is strongly expected. We herein investigated the effects of water-soluble fullerene derivatives: a bis-malonic acid derivative and three types of proline-type fullerene derivatives, on adipogenesis using NIH-3T3 cells overexpressing PPARγ. One of the proline-type fullerene derivatives (P3) harboring three carboxy groups significantly inhibited lipid accumulation and the expression of adipocyte-specific genes, such as aP2, induced by the PPARγ agonist rosiglitazone. On the other hand, the bis-malonic acid derivative (M) and the 2 other proline-type fullerene derivatives (P1, P2), which have two carboxy groups, had no effect on PPARγ-mediated lipid accumulation or the expression of aP2. P3 fullerene also inhibited lipid accumulation induced by the combined stimulation with 3-isobutyl-1-methylxanthine (IBMX), dexamethasone, and insulin in 3T3-L1 preadipocytes. During the differentiation of 3T3-L1 cells into adipocytes, P3 fullerene did not affect the expression of C/EBPδ, C/EBPβ, or PPARγ, but markedly inhibited that of aP2 mRNA. These results suggest that P3 fullerene exhibits anti-obesity activity by preventing the activation of PPARγ.

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Fullerene derivative inhibits the rosiglitazone-induced adipogenesis.

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Fullerene derivative inhibits the rosiglitazone-induced expression of aP2 mRNA.

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Fullerene derivative inhibits adipogenesis of 3T3-L1 preadipocyte.

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Fullerene derivative inhibits the activation of PPARγ in 3T3-L1 preadipocyte.

[Study of cytokine signaling: the quest for immunomodulatory drugs interacting with cytokine production and activity]

I have been engaged in research and education in the fields of immunology and biochemistry at a medical college and college of pharmacy for 40 years. The original reasons why I began studying cytokines and some of the interests that have motivated me to continue working in the field of cytokine research are described: 1) the roles of cytokines in various immunological and inflammatory diseases (e.g., chemokines in bacterial infections and inflammatory diseases, particularly the role of interleukin-5 and eotaxins in eosinophilia); 2) the role of focal adhesion kinase in antiapoptosis and metastasis of melanoma; 3) recent findings on the role of JAK2/STAT pathways, particularly how JAK2V617F mutation induces dysregulated proliferation and tumorigenesis; and 4) the interactions of various chemical compounds and natural products in cytokine gene activation and signaling. Previous discoveries and published findings by my research group are described, along with comments and discussion pertaining to recent developments in the field.

Effect of chemical modification on the ability of pyrrolidinium fullerene to induce apoptosis of cells transformed by JAK2 V617F mutant

JAK2 V617F mutant, a gene responsible for human myeloproliferative neoplasms (MPNs), causes not only cellular transformation but also resistance to various anti-cancer drugs. We previously reported that pyrrolidinium fullerene markedly induced the apoptosis of JAK2 V617F mutant-induced transformed cells through the reduction of apoptosis signal-regulating kinase 1 (ASK1), following inhibition of the c-Jun N-terminal kinase (JNK) pathway. In the current study, we found that the replacement of the 2-hydrogen atom (H) or N-methyl group (CH3) by the butyl group (C4C9) caused the more than 3-fold potent cytotoxic effects on cells transformed by the JAK2 V617F mutant. Strikingly, these chemical modification of pyrrolidinium fullerene resulted in more marked reduction of ASK1 protein and a more potent inhibitory effect on the JNK signaling cascade. On the other hand, when modified with a longer alkyl group, the derivatives lacked their cytotoxicity. These observations clearly indicate that the modification of pyrrolidinium fullerene with a suitable length of alkyl group such as butyl group enhances its apoptotic effect through inhibition of the ASK1-MKK4/7-JNK pathway.