Mitochondria-derived reactive oxygen species drive GANT61-induced mesothelioma cell apoptosis

Combined treatment with inhibitors of ErbB Receptors and Hh signaling pathways is more effective than single treatment in reducing the growth of malignant mesothelioma both in vitro and in vivo

Malignant mesothelioma (MM) is a rare orphan aggressive neoplasia with low survival rates. Among the other signaling pathways, ErbB receptors and Hh signaling are deregulated in MM. Thus, molecules involved in these signaling pathways could be used for targeted therapy approaches. The aim of this study was to evaluate the effects of inhibitors of Hh- (GANT-61) and ErbB receptors (Afatinib)-mediated signaling pathways, when used alone or in combination, on growth, cell cycle, cell death and autophagy, modulation of molecules involved in transduction pathways, in three human MM cell lines of different histotypes. The efficacy of the combined treatment was also evaluated in a murine epithelioid MM cell line both in vitro and in vivo. This study demonstrated that combined treatment with two inhibitors counteracting the activation of two different signaling pathways involved in neoplastic transformation and progression, such as those activated by ErbB and Hh signaling, is more effective than the single treatments in reducing MM growth in vitro and in vivo. This study may have clinical implications for the development of targeted therapy approaches for MM.

GANT61 plays antitumor effects by inducing oxidative stress through the miRNA-1286/RAB31 axis in osteosarcoma

Osteosarcoma (OS) is a rare malignancy of bone associated with poor clinical outcomes. The antitumor effects of GANT61 on OS is unclear. To investigate antitumor effects and mechanism of GANT61 in OS cells and xenograft model. Effects of GANT61 on cell viability, clone formation, cell cycle, apoptosis, migration, and invasion ability of OS cells were assessed. Reactive oxygen species (ROS) levels measured by dichlorofluorescein fluorescence were used to evaluate oxidative stress. The Xenograft model was constructed to investigate the antitumor effects of GANT61 in vivo. The microRNA (miRNA)-1286 was downregulated, while RAB31 upregulated in OS tissues and cells. GANT61 inhibited viability, migration, and invasion ability of OS cells (SaOS-2 and U2OS), and induced apoptosis and the ROS production, along with miRNA-1286 upregulation and RAB13 downregulation. After knockdown of miRNA-1286, GANT6-induced cell inhibition was attenuated, along with RAB31 upregulation. Inversely, miRNA-1286 overexpression downregulated RAB31. Dual-luciferase reporter assay verified that miR-1286 negatively targeted RAB13. Moreover, the knockdown of RAB31 stimulated apoptosis and ROS production while inhibited viability, migration, and invasion of GANT61-treated cells. In vivo experiments further confirmed that GANT61 inhibited tumor growth and RAB13 expression, but enhanced miRNA-1286. The study demonstrated that GANT61 inhibited cell aggressive phenotype and tumor growth by inducing oxidative stress through the miRNA-1286/RAB31 axis. Our findings provided a potential antitumor agent for the OS clinical treatment.

Sunitinib-Containing Carborane Pharmacophore with the Ability to Inhibit Tyrosine Kinases Receptors FLT3, KIT and PDGFR-β, Exhibits Powerful In Vivo Anti-Glioblastoma Activity

Simple Summary

Glioblastoma is one of the most aggressive central nervous system tumors. Combinations of therapies, such as tyrosine kinase receptor inhibition and boron neutron capture therapy (BNCT), could offer greater patients benefits over single-therapies. The aim of our study was to assess the potential of sunitinib-carborane hybrid compound 1 as an anti-glioblastoma agent. We confirmed for 1 the ability to inhibit tyrosine kinase receptors, which could promote canonical and non-canonical effects, absence of mutagenicity, ability to cross the blood–brain barrier, and powerful in vivo anti-glioblastoma activity. The overall attractive profile of 1 makes it an interesting compound for a bimodal therapeutic strategy against high grade gliomas.

Abstract

Malignant gliomas are the most common malignant and aggressive primary brain tumors in adults, the prognosis being—especially for glioblastomas—extremely poor. There are no effective treatments yet. However, tyrosine kinase receptor (TKR) inhibitors and boron neutron capture therapy (BNCT), together, have been proposed as future therapeutic strategies. In this sense in our ongoing project of developing new anti-glioblastoma drugs, we identified a sunitinib-carborane hybrid agent, 1, with both in vitro selective cytotoxicity and excellent BNCT-behavior. Consequently, we studied the ability of compound 1 to inhibit TKRs, its promotion of cellular death processes, and its effects on the cell cycle. Moreover, we analyzed some relevant drug-like properties of 1, i.e., mutagenicity and ability to cross the blood–brain barrier. These results encouraged us to perform an in vivo anti-glioblastoma proof of concept assay. It turned out to be a selective FLT3, KIT, and PDGFR-β inhibitor and increased the apoptotic glioma-cell numbers and arrested sub-G1-phase cell cycle. Its in vivo activity in immunosuppressed mice bearing U87 MG human glioblastoma evidenced excellent anti-tumor behavior.

GANT61 Reduces Hedgehog Molecule (GLI1) Expression and Promotes Apoptosis in Metastatic Oral Squamous Cell Carcinoma Cells

Due to its importance in the pathogenesis of oral squamous cell carcinoma (OSCC), the Hedgehog (HH) pathway is considered a potential therapeutic target. We investigated the effects of GANT61, a GLI inhibitor, on HH gene expression, as well as on metastatic OSCC cell proliferation and death. Following culture in DMEM medium, cytotoxicity of GANT61 against different tumor and non-tumor cell types was assessed by alamarBlue assays. Cytotoxicity analysis revealed that the metastatic HSC3 cell line was the most sensitive (IC₅₀: 36 µM) to the tested compound. The compound’s effects on the expression of HH pathways components were analyzed by qPCR and Western blot; cell viability was analyzed by trypan blue assay and flow cytometry were used to investigate cell cycle phase, morphology, and death patterns in HSC3 cells. A significant reduction in mRNA levels of the GLI1 transcription factor was found after 12 h of treatment withGANT61. Protein expression levels of other HH pathway components (PTCH1, SHH, and Gli1) and HSC3 cell viability also decreased after 24 h of treatment. Cell cycle analysis and death pattern evaluations revealed significantly increased nuclear fragmentation in sub-G1 phase, as well as cell death due to apoptosis. In conclusion, the significantly reduced GLI1 gene expression seen in response to the GLI inhibitor indicates diminished downstream activation in HH pathway components. GANT61 significantly reduced cell viability in the metastatic cell line of OSCC and promoted a significant increase in nuclear fragmentation and cell death by apoptosis.

A Gli inhibitor GANT61 suppresses cell proliferation, promotes cell apoptosis and induces G1/G0 cycle retardation with a dose- and time-dependent manner through inhibiting Notch pathway in multiple myeloma

PURPOSE

This study aimed to explore the effect of GANT61 on regulating cell proliferation, cell apoptosis and cell cycle, and to investigate whether GANT61 would function in multiple myeloma (MM) via inhibiting Notch pathway. Methods: RPMI-8226 and U266 cells were treated by GANT61 (0, 2.5, 5.0, 10.0, 20.0, 30.0, 40.0, 50.0 μmol/L) for 18, 24 and 36 hours (h), and cell proliferation was detected by Cell Counting Kit 8. Then these cells were treated by GANT61 at 0, 2.5, 5.0, 10.0 μmol/L for 24 h or treated by 10.0 μmol/L GANT61 for 0, 18, 24 and 36 h, and cell apoptosis rate, apoptosis markers and cell cycle were detected by AV/PI, Western blot, and PI staining. Notch1, Jagged1, Jagged2 and Hes1 expressions were detected by qPCR and Western blot. Further rescue experiments were conducted by upregulating Notch1. Results: In RPMI-8226 and U266 cells, GANT61 inhibited cell proliferation, increased cell apoptosis rate and cell percentage of G1/G0 phase while decreased cell percentage of S phase in a dose- and time-dependent manner. Besides, GANT61 inhibited Notch1, Jagged1, Jagged2 and Hes1 expressions in a dose- and time-dependent manner as well. In rescue experiments, Notch1 upregulation attenuated the inhibition of cell proliferation, promotion of cell apoptosis, induction of G1/G0 cycle retardation and repression of Notch signaling pathway induced by GANT61 treatment in RPMI-8226 and U266 cells. Conclusions: GANT61 suppresses cell proliferation, promotes cell apoptosis and induces G1/G0 cycle retardation with a dose- and time-dependent manner through inhibiting Notch pathway in MM.

ABBREVIATIONS

MM: Multiple myeloma; Hh: Hedgehog; EMT: epithelial mesenchymal transition; AML: acute myeloid leukemia; GANT61: GLI antagonist; DMSO: dimethyl sulfoxide; CCK-8: Cell Counting Kit 8; C-Caspase 3: Cleaved Caspase 3; Bcl-2: B-cell lymphoma-2; RT-qPCR: real-time quantitative polymerase chain reaction; OD: optical density; PTCH1: Patched1.

Role of Sonic hedgehog signaling in cell cycle, oxidative stress, and autophagy of temozolomide resistant glioblastoma

The first-line chemotherapy treatment for Glioblastoma (GBM) - the most aggressive and frequent brain tumor - is temozolomide (TMZ). The Sonic hedgehog (SHH) pathway is involved with GBM tumorigenesis and TMZ chemoresistance. The role of SHH pathway inhibition in the potentiation of TMZ's effects using T98G, U251, and GBM11 cell lines is investigated herein. The combination of GANT-61 and TMZ over 72 hr suggested a synergistic effect. All TMZ-resistant cell lines displayed a significant decrease in cell viability, increased DNA fragmentation and loss of membrane integrity. For T98G cells, G₂ /M arrest was observed, while U251 cells presented a significant increase in reactive oxygen species production and catalase activity. All the cell lines presented acidic vesicles formation correlated to Beclin-1 overexpression. The combined treatment also enhanced GLI1 expression, indicating the presence of select resistant cells. The selective inhibition of the SHH pathway potentiated the cytotoxic effect of TMZ, thus becoming a promising in vitro strategy for GBM treatment.

Arsenic Trioxide and (-)-Gossypol Synergistically Target Glioma Stem-Like Cells via Inhibition of Hedgehog and Notch Signaling

Glioblastoma is one of the deadliest malignancies and is virtually incurable. Accumulating evidence indicates that a small population of cells with a stem-like phenotype is the major culprit of tumor recurrence. Enhanced DNA repair capacity and expression of stemness marker genes are the main characteristics of these cells. Elimination of this population might delay or prevent tumor recurrence following radiochemotherapy. The aim of this study was to analyze whether interference with the Hedgehog signaling (Hh) pathway or combined Hh/Notch blockade using small-molecule inhibitors can efficiently target these cancer stem cells and sensitize them to therapy. Using tumor sphere lines and primary patient-derived glioma cultures we demonstrate that the Hh pathway inhibitor GANT61 (GANT) and the arsenic trioxide (ATO)-mediated Hh/Notch inhibition are capable to synergistically induce cell death in combination with the natural anticancer agent (−)-Gossypol (Gos). Only ATO in combination with Gos also strongly decreased stemness marker expression and prevented sphere formation and recovery. These synergistic effects were associated with distinct proteomic changes indicating diminished DNA repair and markedly reduced stemness. Finally, using an organotypic brain slice transplantation model, we show that combined ATO/Gos treatment elicits strong growth inhibition or even complete elimination of tumors. Collectively, our data show for the first time that ATO and Gos, two drugs that can be used in the clinic, represent a promising targeted therapy approach for the synergistic elimination of glioma stem-like cells.

Role of GLI Transcription Factors in Pathogenesis and Their Potential as New Therapeutic Targets

GLI transcription factors have important roles in intracellular signaling cascade, acting as the main mediators of the HH-GLI signaling pathway. This is one of the major developmental pathways, regulated both canonically and non-canonically. Deregulation of the pathway during development leads to a number of developmental malformations, depending on the deregulated pathway component. The HH-GLI pathway is mostly inactive in the adult organism but retains its function in stem cells. Aberrant activation in adult cells leads to carcinogenesis through overactivation of several tightly regulated cellular processes such as proliferation, angiogenesis, EMT. Targeting GLI transcription factors has recently become a major focus of potential therapeutic protocols.

Pim kinase isoforms: devils defending cancer cells from therapeutic and immune attacks

Pim kinases are being implicated in oncogenic process in various human cancers. Pim kinases primarily deal with three broad categories of functions such as tumorigenesis, protecting cells from apoptotic signals and evading immune attacks. Here in this review, we discuss the regulation of Pim kinases and their expression, and how these kinases defend cancer cells from therapeutic and immune attacks with special emphasis on how Pim kinases maintain their own expression during apoptosis and cellular transformation, defend mitochondria during apoptosis, defend cancer cells from immune attack, defend cancer cells from therapeutic attack, choose localization, self-regulation, activation of oncogenic transcription, metabolic regulation and so on. In addition, we also discuss how Pim kinases contribute to tumorigenesis by regulating cellular transformation and glycolysis to reinforce the importance of Pim kinases in cancer and cancer stem cells.

Downregulation of TFAM inhibits the tumorigenesis of non-small cell lung cancer by activating ROS-mediated JNK/p38MAPK signaling and reducing cellular bioenergetics

Mitochondrial transcription factor A (TFAM) is essential for the replication, transcription and maintenance of mitochondrial DNA (mtDNA). The role of TFAM in non-small cell lung cancer (NSCLC) remains largely unknown. Herein, we report that downregulation of TFAM in NSCLC cells resulted in cell cycle arrest at G1 phase and significantly blocked NSCLC cell growth and migration through the activation of reactive oxygen species (ROS)-induced c-Jun amino-terminal kinase(JNK)/p38 MAPK signaling and decreased cellular bioenergetics. We further found that TFAM downregulation in NSCLC cells led to increased apoptotic cell death and enhanced the sensitivity of NSCLC cells to cisplatin. Tissue microarray (TMA) data showed that elevated expression of TFAM was related to the histological grade and TNM stage of NSCLC patients. We also demonstrated that TFAM is an independent prognostic factor for overall survival of NSCLC patients. Taken together, our findings suggest that TFAM could serve as a potential diagnostic biomarker and molecular target for the treatment of NSCLC, as well as for prediction of the effectiveness of chemotherapy.

The Effect of SHH-Gli Signaling Pathway on the Synovial Fibroblast Proliferation in Rheumatoid Arthritis

Rheumatoid arthritis (RA) is a chronic autoimmune disease characterized by chronic synovitis. This study aims to investigate the role of sonic hedgehog (SHH)-Gli signaling pathway in synovial fibroblast proliferation in rheumatoid arthritis. The expression of serum SHH in RA patients group was significantly increased compared with the systemic lupus erythematosus (SLE), ankylosing spondylitis (AS), and healthy subject (healthy control, HC) groups, respectively; serum SHH expression of RA patients was positively correlated with rheumatoid factor (RF) and anti-cyclic citrullinated peptide antibodies (anti-CCP Ab), while there was no significant correlation between SHH expression and erythrocyte sedimentation rate (ESR). SHH, Ptch, Smo, and Gli molecules were highly expressed in rat RA-synovial fibroblast (RA-SF); after blocking the SHH-Gli signaling pathway with a Gli specific inhibitor, Gli-antagonist 61 (GANT61), RA-SF proliferation was inhibited in a dose-dependent manner and the apoptosis rate of RA-SF was increased as well; the expression levels of fibroblast growth factor receptor 1 (FGFR1) and FGFR3 declined in SF cells after GANT61 treatment. Our results suggest that SHH-Gli pathway is involved in the pathogenesis of RA, and blocking SHH-Gli pathway inhibits RA-SF cell proliferation and increases cell apoptosis, which may shed light on developing new ideas for RA treatment.

The contribution of keratinocytes in capecitabine-stimulated hand-foot-syndrome

Capecitabine, as the first-line treatment for multiple tumor types, has a serious drawback of hand-foot-syndrome (HFS) that limits its clinical use. However, the pathophysiology and mechanism of capecitabine-induced HFS is rarely known. Here we built the experimental mouse model of HFS induced by capecitabine at first and it was shown that 3 of 6 mice appeared HFS in the 5th day and 5 mice occurred HFS in the 30th day. The corneous layer was reduced in capecitabine-induced HFS in vivo. Moreover, we found that capecitabine could significantly induce keratinocytes cells death in vitro through activated apoptosis pathway and decreased mitochondrial membrane potential. In conclusion, these results suggested that HFS of capecitabine may be developed from reduction of corneous layer through stimulation of intracellular mitochondrial dysfunction following activation of caspase-dependent apoptosis pathway.

Mitochondrial generation of superoxide and hydrogen peroxide as the source of mitochondrial redox signaling

This review examines the generation of reactive oxygen species by mammalian mitochondria, and the status of different sites of production in redox signaling and pathology. Eleven distinct mitochondrial sites associated with substrate oxidation and oxidative phosphorylation leak electrons to oxygen to produce superoxide or hydrogen peroxide: oxoacid dehydrogenase complexes that feed electrons to NAD⁺; respiratory complexes I and III, and dehydrogenases, including complex II, that use ubiquinone as acceptor. The topologies, capacities, and substrate dependences of each site have recently clarified. Complex III and mitochondrial glycerol 3-phosphate dehydrogenase generate superoxide to the external side of the mitochondrial inner membrane as well as the matrix, the other sites generate superoxide and/or hydrogen peroxide exclusively in the matrix. These different site-specific topologies are important for redox signaling. The net rate of superoxide or hydrogen peroxide generation depends on the substrates present and the antioxidant systems active in the matrix and cytosol. The rate at each site can now be measured in complex substrate mixtures. In skeletal muscle mitochondria in media mimicking muscle cytosol at rest, four sites dominate, two in complex I and one each in complexes II and III. Specific suppressors of two sites have been identified, the outer ubiquinone-binding site in complex III (site III_Qo) and the site in complex I active during reverse electron transport (site I_Q). These suppressors prevent superoxide/hydrogen peroxide production from a specific site without affecting oxidative phosphorylation, making them excellent tools to investigate the status of the sites in redox signaling, and to suppress the sites to prevent pathologies. They allow the cellular roles of mitochondrial superoxide/hydrogen peroxide production to be investigated without catastrophic confounding bioenergetic effects. They show that sites III_Qo and I_Q are active in cells and have important roles in redox signaling (e.g. hypoxic signaling and ER-stress) and in causing oxidative damage in a variety of biological contexts.

Targeting the Hedgehog signaling pathway in cancer: beyond Smoothened

An essential role for Hedgehog (Hh) signaling in human cancer has been established beyond doubt. At present, targeting Hh signaling has mainly been investigated with SMO inhibitors. Unfortunately, resistance against currently used SMO inhibitors has already been observed in basal cell carcinoma (BCC) patients. Therefore, the use of Hh inhibitors targeting the signaling cascade more downstream of SMO could represent a more promising strategy. Furthermore, besides the classical canonical way of Hh signaling activation, non-canonical activation of the GLI transcription factors by multiple important signaling pathways (e.g. MAPK, PI3K, TGFβ) has also been described, pinpointing the importance of targeting the transcription factors GLI1/2. The most promising agent in this context is probably the GLI1/2 inhibitor GANT61 which has been investigated preclinically in numerous tumor types in the last few years. In this review, the emerging role of Hh signaling in cancer is critically evaluated focusing on the potential of targeting Hh signaling more downstream of SMO, i.e. at the level of the GLI transcription factors. Furthermore, the working mechanism and therapeutic potential of the most extensively studied GLI inhibitor in human cancer, i.e. GANT61, is discussed in detail. In conclusion, GANT61 appears to be highly effective against human cancer cells and in xenograft mouse models, targeting almost all of the classical hallmarks of cancer and could hence represent a promising treatment option for human cancer.

Novel PKC-ζ to p47 phox interaction is necessary for transformation from blebbishields

Cancer stem cells are capable of transformation after apoptosis through the blebbishield emergency program. Reactive oxygen species (ROS) play an essential role in transformation. Understanding how ROS are linked to blebbishield-mediated transformation is necessary to develop efficient therapeutics that target the resurrection of cancer stem cells. Here we demonstrate that a novel PKC-ζ to p47^phox interaction is required for ROS production in cancer cells. The combined use of the S6K inhibitor BI-D1870 with TNF-α inhibited the PKC-ζ to p47^phox interaction, inhibited ROS production, degraded PKC-ζ, and activated caspases-3 and -8 to block transformation from blebbishields. BI-D1870 also inhibited transformation from cycloheximide-generated blebbishields. Thus ROS and the PKC-ζ to p47^phox interaction are valid therapeutic targets to block transformation from blebbishields.

Substance P Inhibits Hyperosmotic Stress-Induced Apoptosis in Corneal Epithelial Cells through the Mechanism of Akt Activation and Reactive Oxygen Species Scavenging via the Neurokinin-1 Receptor

Hyperosmolarity has been recognized as an important pathological factor in dry eye leading to ocular discomfort and damage. As one of the major neuropeptides of corneal innervation, substance P (SP) has been shown to possess anti-apoptotic effects in various cells. The aim of this study was to determine the capacity and mechanism of SP against hyperosmotic stress-induced apoptosis in cultured corneal epithelial cells. The cells were exposed to hyperosmotic stress by the addition of high glucose in the presence or absence of SP. The results showed that SP inhibited hyperosmotic stress-induced apoptosis of mouse corneal epithelial cells. Moreover, SP promoted the recovery of phosphorylated Akt level, mitochondrial membrane potential, Ca²⁺ contents, intracellular reactive oxygen species (ROS) and glutathione levels that impaired by hyperosmotic stress. However, the antiapoptotic capacity of SP was partially suppressed by Akt inhibitor or glutathione depleting agent, while the neurokinin-1 (NK-1) receptor antagonist impaired Akt activation and ROS scavenging that promoted by SP addition. In conclusion, SP protects corneal epithelial cells from hyperosmotic stress-induced apoptosis through the mechanism of Akt activation and ROS scavenging via the NK-1 receptor.

Porcine parvovirus infection activates mitochondria-mediated apoptotic signaling pathway by inducing ROS accumulation

Background

Porcine parvovirus (PPV) infection primarily causes reproductive failure of pregnant swine and results in host cell death. Boars, as an important disseminator, shed PPV to sows via semen. PPV infects and numerously replicates in boar testicle, which results in damage of swine testicle in vivo. Reactive oxygen species (ROS), a mediator of cell apoptosis, play a crucial role in the mitochondria apoptotic pathway. However, whether PPV infection induces ST cells apoptosis and ROS accumulation is still unclear.

Methods

To determine the effects of PPV infection on the apoptosis, we detected morphological changes, DNA ladder, activities of caspases, and expression of PARP in PPV-infected ST cells. Moreover, aiming to investigate the effect of PPV infection on the mitochondrial apoptotic pathway and ROS accumulation, we detected the Δψm, apoptosis-related genes, and ROS. To investigate the role of ROS in the process of PPV-induced apoptosis, the ST cells were infected with PPV and treated with the ROS antioxidants. The ROS level was measured using Reactive Oxygen Species Assay Kit and the Δψm, expression level of Bcl-2, translocation of Bax, and redistribution of mitochondria cytochrome c were tested.

Results

In this study, we demonstrated that PPV infection could induce apoptosis that was characterized by morphological changes, DNA fragmentation and activation of caspases. Moreover, PPV infection suppressed Bcl-2 expression, enhanced Bax expression and translocation to mitochondria, decreased the mitochondrial transmembrane potential, and triggered the release of cytochrome c, which caused the subsequent activation of caspase-9 and caspase-3 and initiation of apoptosis. However, during the process of PPV-induced apoptosis, the protein levels of Fas and FasL were not affected. Further studies showed that PPV infection caused ROS accumulation. Inhibition of ROS could reduce mitochondrial transmembrane potential and could significantly block ST cells apoptosis via suppressing Bax translocation, cytochrome c and caspase-3 activation.

Conclusions

All these results suggest that PPV-induced ROS accumulation mediates apoptosis in ST cells, which provided theoretical basis for the molecular pathogenesis of PPV infection.

Herbal Medicine Offered as an Initiative Therapeutic Option for the Management of Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is a common malignant cancer and is the third leading cause of death worldwide. Effective treatment of this disease is limited by the complicated molecular mechanism underlying HCC pathogenesis. Thus, therapeutic options for HCC management are urgently needed. Targeting the Wnt/β-catenin, Hedgehog, Notch, and Hippo-YAP signaling pathways in cancer stem cell development has been extensively investigated as an alternative treatment. Herbal medicine has emerged as an initiative therapeutic option for HCC management because of its multi-level, multi-target, and coordinated intervention effects. In this article, we summarized the recent progress and clinical benefits of targeting the above mentioned signaling pathways and using natural products such as herbal medicine formulas to treat HCC. Proving the clinical success of herbal medicine is expected to deepen the knowledge on herbal medicine efficiency and hasten the adoption of new therapies. Copyright © 2016 John Wiley & Sons, Ltd.

A novel 4-fluorobenzenetelluronic trimethyltin ester: synthesis, characterization and in vitro cytotoxicity assessment

A novel 4-fluorobenzenetelluronic trimethyltin ester (Me₃Sn)₄[p-F-PhTe(μ-O)(OH)O₂]₂ (1) has been prepared and structurally characterized, and apoptotic cytotoxicity assessments for A549 cells are made.

A novel therapeutic approach against B-cell non-Hodgkin's lymphoma through co-inhibition of Hedgehog signaling pathway and autophagy

B-cell non-Hodgkin's lymphoma (B-NHL) is one of the most common types of cancer in the world, with half of the patients dying due to the resistance or tolerance against the treatment. Thus, a novel therapeutic approach for B-NHL treatment was urgently needed. In this study, we investigated the potential of co-inhibition of Hedgehog signaling pathway (Hh) and autophagy in B-NHL therapy. We reported that vismodegib, an inhibitor of Hedgehog signaling pathway, could block the Hh pathway and induce cytotoxicity and apoptosis in B-NHL Raji cells. During this process, autophagy was activated as a response to Hh inhibition. Importantly, inhibition of autophagy potentiated the cytotoxicity and caspase 3-dependent apoptosis induced by vismodegib in B-NHL cells. Furthermore, clearance of ROS generation caused a decreased activity of autophagy and attenuated cytotoxicity in vismodegib-treated cells, while inhibition of autophagy accelerated the formation of ROS, indicating that ROS was required for vismodegib-induced autophagy and cytotoxicity in B-NHL cells. Our results demonstrated that co-inhibition of Hh pathway and autophagy could potently kill B-NHL cells and highlighted a novel approach for B-NHL therapy by co-inhibition of Hh pathway and cytoprotective autophagy.

Hedgehog Signaling in Malignant Pleural Mesothelioma

Malignant pleural mesothelioma (MPM) is a cancer associated with exposure to asbestos fibers, which accumulate in the pleural space, damage tissue and stimulate regeneration. Hedgehog signaling is a pathway important during embryonic mesothelium development and is inactivated in adult mesothelium. The pathway is reactivated in some MPM patients with poor clinical outcome, mainly mediated by the expression of the ligands. Nevertheless, mutations in components of the pathway have been observed in a few cases. Data from different MPM animal models and primary culture suggest that both autocrine and paracrine Hedgehog signaling are important to maintain tumor growth. Drugs inhibiting the pathway at the level of the smoothened receptor (Smo) or glioma-associated protein transcription factors (Gli) have been used mostly in experimental models. For clinical development, biomarkers are necessary for the selection of patients who can benefit from Hedgehog signaling inhibition.