Farnesyltransferase inhibitor manumycin targets IL1β-Ras-HIF-1α axis in tumor cells of diverse origin

ACE2 in chronic disease and COVID-19: gene regulation and post-translational modification

Angiotensin-converting enzyme 2 (ACE2), a counter regulator of the renin-angiotensin system, provides protection against several chronic diseases. Besides chronic diseases, ACE2 is the host receptor for SARS-CoV or SARS-CoV-2 virus, mediating the first step of virus infection. ACE2 levels are regulated by transcriptional, post-transcriptional, and post-translational regulation or modification. ACE2 transcription is enhanced by transcription factors including Ikaros, HNFs, GATA6, STAT3 or SIRT1, whereas ACE2 transcription is reduced by the transcription factor Brg1-FoxM1 complex or ERRα. ACE2 levels are also regulated by histone modification or miRNA-induced destabilization. The protein kinase AMPK, CK1α, or MAP4K3 phosphorylates ACE2 protein and induces ACE2 protein levels by decreasing its ubiquitination. The ubiquitination of ACE2 is induced by the E3 ubiquitin ligase MDM2 or UBR4 and decreased by the deubiquitinase UCHL1 or USP50. ACE2 protein levels are also increased by the E3 ligase PIAS4-mediated SUMOylation or the methyltransferase PRMT5-mediated ACE2 methylation, whereas ACE2 protein levels are decreased by AP2-mediated lysosomal degradation. ACE2 is downregulated in several human chronic diseases like diabetes, hypertension, or lung injury. In contrast, SARS-CoV-2 upregulates ACE2 levels, enhancing host cell susceptibility to virus infection. Moreover, soluble ACE2 protein and exosomal ACE2 protein facilitate SARS-CoV-2 infection into host cells. In this review, we summarize the gene regulation and post-translational modification of ACE2 in chronic disease and COVID-19. Understanding the regulation and modification of ACE2 may help to develop prevention or treatment strategies for ACE2-mediated diseases.

Sphingolipids and Lymphomas: A Double-Edged Sword

Lymphomas are a highly heterogeneous group of hematological neoplasms. Given their ethiopathogenic complexity, their classification and management can become difficult tasks; therefore, new approaches are continuously being sought. Metabolic reprogramming at the lipid level is a hot topic in cancer research, and sphingolipidomics has gained particular focus in this area due to the bioactive nature of molecules such as sphingoid bases, sphingosine-1-phosphate, ceramides, sphingomyelin, cerebrosides, globosides, and gangliosides. Sphingolipid metabolism has become especially exciting because they are involved in virtually every cellular process through an extremely intricate metabolic web; in fact, no two sphingolipids share the same fate. Unsurprisingly, a disruption at this level is a recurrent mechanism in lymphomagenesis, dissemination, and chemoresistance, which means potential biomarkers and therapeutical targets might be hiding within these pathways. Many comprehensive reviews describing their role in cancer exist, but because most research has been conducted in solid malignancies, evidence in lymphomagenesis is somewhat limited. In this review, we summarize key aspects of sphingolipid biochemistry and discuss their known impact in cancer biology, with a particular focus on lymphomas and possible therapeutical strategies against them.

Transforming Growth Factor-Beta-Regulated LncRNA-MUF Promotes Invasion by Modulating the miR-34a Snail1 Axis in Glioblastoma Multiforme

Transforming growth factor beta (TGF-β)-regulated long-non-coding RNAs (lncRNAs) modulate several aspects of tumor development such as proliferation, invasion, metastasis, epithelial to mesenchymal transition (EMT), and drug resistance in various cancers, including Glioblastoma multiforme (GBM). We identified several novel differentially expressed lncRNAs upon TGF-β treatment in glioma cells using genome-wide microarray screening. We show that TGF-β induces lncRNA-MUF in glioma cells, and its expression is significantly upregulated in glioma tissues and is associated with poor overall survival of GBM patients. Knockdown of lncRNA-MUF reduces proliferation, migration, and invasion in glioma cells and sensitizes them to temozolomide (TMZ)-induced apoptosis. In addition, lncRNA-MUF downregulation impairs TGF-β-induced smad2/3 phosphorylation. In line with its role in regulating invasion, lncRNA-MUF functions as a competing endogenous RNA (ceRNA) for miR-34a and promotes Snail1 expression. Collectively, our findings suggest lncRNA-MUF as an attractive therapeutic target for GBM.

The role of hypoxia-inducible factors in neovascular age-related macular degeneration: a gene therapy perspective

Understanding the mechanisms that underlie age-related macular degeneration (AMD) has led to the identification of key molecules. Hypoxia-inducible transcription factors (HIFs) have been associated with choroidal neovascularization and the progression of AMD into the neovascular clinical phenotype (nAMD). HIFs regulate the expression of multiple growth factors and cytokines involved in angiogenesis and inflammation, hallmarks of nAMD. This knowledge has propelled the development of a new group of therapeutic strategies focused on gene therapy. The present review provides an update on current gene therapies in ocular angiogenesis, particularly nAMD, from both basic and clinical perspectives.

Zinc oxide nanoparticles induce apoptosis and autophagy in human ovarian cancer cells

Background

Zinc oxide nanoparticles (ZnO NPs) are frequently used in industrial products such as paint, surface coating, and cosmetics, and recently, they have been explored in biologic and biomedical applications. Therefore, this study was undertaken to investigate the effect of ZnO NPs on cytotoxicity, apoptosis, and autophagy in human ovarian cancer cells (SKOV3).

Methods

ZnO NPs with a crystalline size of 20 nm were characterized with various analytical techniques, including ultraviolet-visible spectroscopy, X-ray diffraction, transmission electron microscopy, Fourier transform infrared spectroscopy, and atomic force microscopy. The cytotoxicity, apoptosis, and autophagy were examined using a series of cellular assays.

Results

Exposure of cells to ZnO NPs resulted in a dose-dependent loss of cell viability, and the characteristic apoptotic features such as rounding and loss of adherence, enhanced reactive oxygen species generation, and loss of mitochondrial membrane potential were observed in the ZnO NP-treated cells. Furthermore, the cells treated with ZnO NPs showed significant double-strand DNA breaks, which are gained evidences from significant number of γ-H₂AX and Rad51 expressed cells. ZnO NP-treated cells showed upregulation of p53 and LC3, indicating that ZnO NPs are able to upregulate apoptosis and autophagy. Finally, the Western blot analysis revealed upregulation of Bax, caspase-9, Rad51, γ-H₂AX, p53, and LC3 and downregulation of Bcl-2.

Conclusion

The study findings demonstrated that the ZnO NPs are able to induce significant cytotoxicity, apoptosis, and autophagy in human ovarian cells through reactive oxygen species generation and oxidative stress. Therefore, this study suggests that ZnO NPs are suitable and inherent anticancer agents due to their several favorable characteristic features including favorable band gap, electrostatic charge, surface chemistry, and potentiation of redox cycling cascades.

New tricks for human farnesyltransferase inhibitor: cancer and beyond

Human protein farnesyltransferase (FTase) catalyzes the addition of a C15-farnesyl lipid group to the cysteine residue located in the COOH-terminal tetrapeptide motif of a variety of important substrate proteins, including well-known Ras protein superfamily. The farnesylation of Ras protein is required both for its normal physiological function, and for the transforming capacity of its oncogenic mutants. Over the last several decades, FTase inhibitors (FTIs) were developed to disrupt the farnesylation of oncogenic Ras as anti-cancer agents, and some of them have entered cancer clinical investigation. On the other hand, some substrates of FTase were demonstrated to be related with other human diseases, including Hutchinson-Gilford progeria syndrome, chronic hepatitis D, and cardiovascular diseases. In this review, we summarize the roles of FTase in malignant transformation, proliferation, apoptosis, angiogenesis, and metastasis of tumor cells, and the recently anticancer clinical research advances of FTIs. The therapeutic prospect of FTIs on several other human diseases is also discussed.

Antitumor effect of the combination of manumycin A and Immodin is associated with antiplatelet activity and increased granulocyte tumor infiltration in a 4T1 breast tumor model

Manumycin A is a natural antibiotic isolated from Streptomyces parvulus with broad range of biological activities including antineoplastic activity in several in vitro and in vivo cancer models. Immodin [dialyzable leukocyte extract (DLE)] is a dialysate released from disintegrated blood leukocytes of healthy donors which exerts immunonormalizing effects on cell-mediated immune responses. The aim of the present study was to explore the antitumor potential of the combination of manumycin A and Immodin in an experimental breast cancer model. Experiments were carried using a 4T1 tumor-bearing BALB/c mouse model. Survival analysis, tumor growth, hematological and biochemical profiles, leukocyte differential, phagocytic activity of leukocytes and histology of the primary tumor were examined. The combination treatment suppressed the tumor growth and prolonged the survival of tumor-bearing mice, decreased the number of monocytes, plateletes and plateletcrit in peripheral blood of the tumor-bearing mice and increased the infiltration of neutrophils and eosinophils in the primary tumor. Moreover, individual therapies enhanced the phagocytic activity of monocytes and neutrophils. These findings demonstrate the antitumor effect of the combination of manumycin A and Immodin in 4T1 tumor-bearing mice associated with strong antiplatelet activity and innate immunity activation.

Manumycin A downregulates release of proinflammatory cytokines from TNF alpha stimulated human monocytes

Macrolide antibiotics such as azithromycin or clarithromycin are known to have potent anti-inflammatory and immunomodulatory effects but these properties cannot be widely used due to a risk of bacterial resistance. We studied another polyketide antibiotic, structurally related manumycin A known as a streptomycete derived farnesyltransferase inhibitor with limited antibacterial effects, with respect to its potential regulation of mRNA expression of several genes associated with proinflammatory responses. Downregulation of mRNA for IL-6, TLR-8, IL-1 beta and IL-10 was found in THP-1 cells after 4h stimulation with TNF alpha in the presence of manumycin A and downregulated TLR-8 and EGR-1 genes were observed after 8h. Among the genes upregulated in response to manumycin were HMOX-1, TNFRSF10A, IL-1R1, TICAM2, NLRP12 after 4h and only IL-1R1 after 8h. Furthermore, manumycin A was found to inhibit IL-1beta, IL-6, and IL-8 production in TNF alpha stimulated THP-1 cells and peripheral blood monocytes in a dose dependent manner (0.25-1 μM of manumycin A) without affecting cell viability. Cell viability of blood monocytes decreased by about 30% at manumycin A doses of 2-5 μM. Manumycin A also inhibited IL-18 release from THP-1 cells, while in cultures of blood monocytes, this cytokine was not detectable. That manumycin A mediated downregulation of proinflammatory genes in human monocytes confirmed by a measurement of cytokine levels in culture supernatants, together with a very limited effect on cell viability, might suggest potential anti-inflammatory properties of this polyketide antibiotic.

Glioblastoma multiforme: Pathogenesis and treatment

Each year, about 5-6 cases out of 100,000 people are diagnosed with primary malignant brain tumors, of which about 80% are malignant gliomas (MGs). Glioblastoma multiforme (GBM) accounts for more than half of MG cases. They are associated with high morbidity and mortality. Despite current multimodality treatment efforts including maximal surgical resection if feasible, followed by a combination of radiotherapy and/or chemotherapy, the median survival is short: only about 15months. A deeper understanding of the pathogenesis of these tumors has presented opportunities for newer therapies to evolve and an expectation of better control of this disease. Lately, efforts have been made to investigate tumor resistance, which results from complex alternate signaling pathways, the existence of glioma stem-cells, the influence of the blood-brain barrier as well as the expression of 0(6)-methylguanine-DNA methyltransferase. In this paper, we review up-to-date information on MGs treatment including current approaches, novel drug-delivering strategies, molecular targeted agents and immunomodulative treatments, and discuss future treatment perspectives.

Epigenetic regulation of angiotensin-converting enzyme 2 (ACE2) by SIRT1 under conditions of cell energy stress

ACE2 (angiotensin-converting enzyme 2) counterbalances the actions of ACE (angiotensin-converting enzyme) by metabolizing its catalytic product, the vasoactive and fibrogenic peptide AngII (angiotensin II), into Ang-(1-7) [angiotensin-(1-7)]. Enhanced ACE2 expression may be protective in diabetes, cardiovascular disease and cancer. However, relatively little is known about the specific physiological factors regulating ACE2 expression. In the present paper, we show, by Western blotting and qPCR (quantitative real-time PCR), that ACE2 expression is increased under conditions of cell stress, including hypoxic conditions, IL (interleukin)-1β treatment and treatment with the AMP mimic AICAR (5-amino-4-imidazolecarboxamide riboside). The NAD+-dependent deacetylase SIRT1 (silent information regulator T1) was found to be up-regulated after AICAR treatment but, conversely, was down-regulated after IL-1β treatment. ChIP analysis demonstrated that SIRT1 bound to the ACE2 promoter and that binding was increased after AICAR treatment, but decreased after IL-1β treatment. Inhibition of SIRT1 activity ablated the AICAR-induced increase in ACE2. In conclusion, we have established that the expression of the ACE2 transcript is controlled by the activity of SIRT1 under conditions of energy stress.

Inhibition of farnesyltransferase reduces angiogenesis by interrupting endothelial cell migration

Inhibitors of farnesyltransferase (FTI) have been developed for cancer treatment for more than a decade. Aside from being a therapeutic target in tumor cells, little is known about the role of farnesyltransferase (FTase) in other physiological processes. In this study, we revealed the involvement of FTase in angiogenesis and showed that FTI inhibited angiogenesis by directly acting on endothelial cells. Inhibition of FTase interrupted cell migration in vitro and in vivo. In addition, we found that FTase was important for cell polarization, cell spreading and pseudopodia formation. We also found that FTase interacted with microtubule end binding protein 1 (EB1) and that this interaction was critical for the localization of EB1 to microtubule tips. Our findings thus offer novel insight into the functions of FTase in endothelial cells and provide valuable information for the use of FTI in cancer therapy.