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Cell Discovery 2018The mammalian target of rapamycin (mTOR) pathway is commonly activated in human cancers. The activity of mTOR complex 1 (mTORC1) signaling is supported by the...
The mammalian target of rapamycin (mTOR) pathway is commonly activated in human cancers. The activity of mTOR complex 1 (mTORC1) signaling is supported by the intracellular positioning of cellular compartments and vesicle trafficking, regulated by Rab GTPases. Here we showed that tuftelin 1 (TUFT1) was involved in the activation of mTORC1 through modulating the Rab GTPase-regulated process. TUFT1 promoted tumor growth and metastasis. Consistently, the expression of TUFT1 correlated with poor prognosis in lung, breast and gastric cancers. Mechanistically, TUFT1 physically interacted with RABGAP1, thereby modulating intracellular lysosomal positioning and vesicular trafficking, and promoted mTORC1 signaling. In addition, expression of predicted sensitivity to perifosine, an alkylphospholipid that alters the composition of lipid rafts. Perifosine treatment altered the positioning and trafficking of cellular compartments to inhibit mTORC1. Our observations indicate that TUFT1 is a key regulator of the mTORC1 pathway and suggest that it is a promising therapeutic target or a biomarker for tumor progression.
PubMed: 29423269
DOI: 10.1038/s41421-017-0001-2 -
Oncogene Apr 2018Cancer cell migration requires that cells respond and adapt to their surroundings. In the absence of extracellular matrix cues, cancer cells will undergo a mesenchymal...
Cancer cell migration requires that cells respond and adapt to their surroundings. In the absence of extracellular matrix cues, cancer cells will undergo a mesenchymal to ameboid transition, whereas a highly confining space will trigger a switch to "leader bleb-based" migration. To identify oncogenic signaling pathways mediating these transitions, we undertook a targeted screen using clinically useful inhibitors. Elevated Src activity was found to change actin and focal adhesion dynamics, whereas inhibiting Src triggered focal adhesion disassembly and blebbing. On non-adherent substrates and in collagen matrices, amoeboid-like, blebbing cells having high Src activity formed protrusions of the plasma membrane. To evaluate the role of Src in confined cells, we use a novel approach that places cells under a slab of polydimethylsiloxane (PDMS), which is held at a defined height. Using this method, we find that leader bleb-based migration is resistant to Src inhibition. High Src activity was found to markedly change the architecture of cortical actomyosin, reduce cell mechanical properties, and the percentage of cells that undergo leader bleb-based migration. Thus, Src is a signal transducer that can potently influence transitions between migration modes with implications for the rational development of metastasis inhibitors.
Topics: Actins; Amino Acid Substitution; Butadienes; Cell Adhesion; Cell Movement; Dasatinib; Humans; Imidazoles; Mutant Proteins; Neoplasms; Nitriles; Phosphorylcholine; Protein Kinase Inhibitors; Proto-Oncogene Proteins pp60(c-src); Quinolines; Tumor Cells, Cultured
PubMed: 29379163
DOI: 10.1038/s41388-017-0071-5 -
Biochemical Pharmacology Jan 2018Autophagy is a major protein degradation pathway capable of upholding cellular metabolism under nutrient limiting conditions, making it a valuable resource to highly... (Review)
Review
Autophagy is a major protein degradation pathway capable of upholding cellular metabolism under nutrient limiting conditions, making it a valuable resource to highly proliferating tumour cells. Although the regulatory machinery of the autophagic pathway has been well characterized, accurate modulation of this pathway remains complex in the context of clinical translatability for improved cancer therapies. In particular, the dynamic relationship between the rate of protein degradation through autophagy, i.e. autophagic flux, and the susceptibility of tumours to undergo apoptosis remains largely unclear. Adding to inefficient clinical translation is the lack of measurement techniques that accurately depict autophagic flux. Paradoxically, both increased autophagic flux as well as autophagy inhibition have been shown to sensitize cancer cells to undergo cell death, indicating the highly context dependent nature of this pathway. In this article, we aim to disentangle the role of autophagy modulation in tumour suppression by assessing existing literature in the context of autophagic flux and cellular metabolism at the interface of mitochondrial function. We highlight the urgency to not only assess autophagic flux more accurately, but also to center autophagy manipulation within the unique and inherent metabolic properties of cancer cells. Lastly, we discuss the challenges faced when targeting autophagy in the clinical setting. In doing so, it is hoped that a better understanding of autophagy in cancer therapy is revealed in order to overcome tumour chemoresistance through more controlled autophagy modulation in the future.
Topics: Animals; Antineoplastic Agents; Autophagy; Cell Death; Humans; Neoplasms
PubMed: 29203368
DOI: 10.1016/j.bcp.2017.11.021 -
Food and Chemical Toxicology : An... Jan 2018Neuroinflammation is an early event during diabetic retinopathy (DR) that impacts the dynamics of microglia polarization. Gliosis is a hallmark of DR and we have...
The sp-iminosugar glycolipid 1-dodecylsulfonyl-5N,6O-oxomethylidenenojirimycin (DSO-ONJ) as selective anti-inflammatory agent by modulation of hemeoxygenase-1 in Bv.2 microglial cells and retinal explants.
Neuroinflammation is an early event during diabetic retinopathy (DR) that impacts the dynamics of microglia polarization. Gliosis is a hallmark of DR and we have reported the beneficial effects of 1R-DSO-ONJ, a member of the sp-iminosugar glycolipid (sp-IGL) family, in targeting microglia and reducing gliosis in diabetic db/db mice. Herein, we analyzed the effect of DSO-ONJ, another family compound incorporating a sulfone group that better mimics the phosphate group of phosphatidylinositol ether lipid analogues (PIAs), in Bv.2 microglial cells treated with bacterial lipopolysaccaride (LPS) and in retinal explants from db/db mice. In addition to decreasing iNOS and inflammasome activation, the anti-inflammatory effect of DSO-ONJ was mediated by direct p38α MAPK activation. Computational docking experiments demonstrated that DSO-ONJ binds to p38α MAPK at the same site where PIAs and the alkyl phospholipid perifosine activators do, suggesting similar mechanism of action. Moreover, treatment of microglial cells with DSO-ONJ increased both heme-oxygenase (HO)-1 and Il10 expression regardless the presence of LPS. In retinal explants from db/db mice, DSO-ONJ also induced HO-1 and reduced gliosis. Since IL-10-mediated induction of HO-1 expression is mediated by p38α MAPK activation, our results suggest that this molecular mechanism is involved in the anti-inflammatory effects of DSO-ONJ in microglia.
Topics: Animals; Anti-Inflammatory Agents; Cell Line; Gene Expression Regulation, Enzymologic; Glycolipids; Heme Oxygenase-1; Lipopolysaccharides; Mice; Mice, Inbred NOD; Microglia; Retina; Tissue Culture Techniques
PubMed: 29191728
DOI: 10.1016/j.fct.2017.11.050 -
Medical Science Monitor : International... Nov 2017BACKGROUND Chronic mountain sickness (CMS) has a higher incidence in the plateau region. The one of its principal characters is excessive erythrocytosis. The PI3K-Akt...
BACKGROUND Chronic mountain sickness (CMS) has a higher incidence in the plateau region. The one of its principal characters is excessive erythrocytosis. The PI3K-Akt pathway plays an important role in the process of erythropoiesis, and could downregulate apoptosis by regulating apoptosis-related molecules. In this paper, we explored the change in apoptosis of erythroblasts and the effect of the PI3K-Akt signal pathway on erythroblasts apoptosis in CMS. MATERIAL AND METHODS A total of 22 CMS and 20 non-CMS participants were involved in this study. Bone marrow mononuclear cells were cultured and treated with celecoxib and perifosine in vitro for 72 hours. The apoptotic rate, the mRNA expressions of Akt, Bcl-xl, and caspase-9, and the protein expressions of Akt, p-Akt, Bcl-xl, and caspase-9 were determined by flow cytometry, quantitative RT-PCR, and western-blot technique. RESULTS The apoptotic rate of cultured erythroblasts was lower in the CMS group than in the non-CMS group. It was increased after perifosine intervention. The mRNA and protein expressions of Akt and Bcl-xl were higher and caspase-9 was lower in the CMS group than the non-CMS group. Perifosine induced decreased Bcl-xl mRNA and proteins and p-Akt proteins, and increased caspase-9 mRNA and proteins in vitro. In the CMS group, the hemoglobin concentration was correlated with apoptotic rate negatively and with Bcl-xl mRNA positively in erythroblasts; the erythroblasts apoptotic rate was negatively associated with the Akt mRNA and Bcl-xl mRNA. CONCLUSIONS The erythroblasts apoptosis was downregulated and the PI3K-Akt signal pathway appeared to be involved in the mechanism of decreased erythroblasts apoptosis in CMS.
Topics: Adult; Altitude Sickness; Apoptosis; Bone Marrow Cells; Caspase 9; Celecoxib; China; Chronic Disease; Down-Regulation; Erythroblasts; Humans; Male; Middle Aged; Phosphatidylinositol 3-Kinases; Phosphorylcholine; Primary Cell Culture; Proto-Oncogene Proteins c-akt; Signal Transduction; bcl-X Protein
PubMed: 29176544
DOI: 10.12659/msm.905739 -
Hepatology (Baltimore, Md.) Apr 2018Telomeres protect chromosomal ends from deterioration and have been shown to be susceptible to shortening by reactive oxygen species (ROS)-induced damage. ROS levels...
UNLABELLED
Telomeres protect chromosomal ends from deterioration and have been shown to be susceptible to shortening by reactive oxygen species (ROS)-induced damage. ROS levels increase during the progression from early to advanced hepatocellular carcinoma (HCC). An independent study found that the telomeres in most HCC tissues lengthened during carcinogenic advancement. Activated telomerase has been hypothesized to elongate telomeres during the progression of malignant HCC, but it remains unclear which signaling pathway is necessary for telomerase activation in HCC. Here, we showed using cell lines derived from human HCC that H O , which is a major component of ROS in living organisms, elongates telomeres by increasing telomerase activity through protein kinase B (AKT) activation. The AKT inhibitor, perifosine, decreased telomere length, cellular viability, and H O -mediated migration and invasion capacity in HCC cells while also inhibiting AKT activation, telomere maintenance, and tumor growth in nude mice. Advanced HCC tissues showed a positive correlation among ROS levels, phosphorylated AKT (pAKT) levels, and telomere length. Furthermore, patients with HCC tumors that have high ROS levels and long telomeres displayed poorer survival rates. These data demonstrate the significant utilities of ROS levels, pAKT levels, and telomere length for predicting a poor prognosis in patients with HCC. Taken together, AKT activation could be essential for telomere maintenance in advanced HCC tumors as well as being an important contributor to malignant HCC progression.
CONCLUSION
We showed that H O contributes to telomere elongation through AKT activation in advanced HCC, suggesting that an AKT inhibitor such as perifosine may be useful for treating patients with malignant HCC. (Hepatology 2018;67:1378-1391).
Topics: Adult; Animals; Carcinoma, Hepatocellular; Cell Line, Tumor; Cell Migration Assays; Female; Heterografts; Humans; In Situ Hybridization, Fluorescence; Liver Neoplasms; Male; Mice; Mice, Nude; Middle Aged; Neoplasm Recurrence, Local; Reactive Oxygen Species; Real-Time Polymerase Chain Reaction; Risk Factors; Survival Rate; Telomere; Telomere Homeostasis
PubMed: 29059467
DOI: 10.1002/hep.29604 -
Oncotarget Sep 2017Tripchlorolide (T4) has been shown to induce A549 lung cancer cell death predominantly by activating an autophagy pathway. However, the underlying mechanism remains...
Tripchlorolide (T4) has been shown to induce A549 lung cancer cell death predominantly by activating an autophagy pathway. However, the underlying mechanism remains unclear. Herein, we demonstrated that compared with T4 treatment alone, pretreatment with wortmannin (an inhibitor of phosphatidylinositol 3-kinase), perifosine (an inhibitor of AKT) or rapamycin (an inhibitor of mTOR) combined with a subsequent T4 treatment significantly impaired the cell viability of A549 and A549/DDP lung cancer cells. We found that either treatment scheme markedly reduced the activity of P13K and AKT. Expression of LC3II increased in parallel to the increase of the T4 concentration in both A549 and A549/DDP cells and was repressed by overexpression of AKT. The expression levels of PI3-K, PI3-P, AKT, TSC2, mTOR, p70S6K and 4E-BP1 were minimally affected by the wortmannin, perifosine, or rapamycin plus T4 treatments, but their phosphorylated products were greatly affected in A549 lung cancer cells and slightly affected in A549/DDP lung cancer cells. These results indicate that T4 induces autophagy in lung cancer cells by inhibiting the PI3K/AKT/mTOR signaling pathway. We further found that T4 decreased expression of MDR1 and improved cisplatin sensitivity of A549/DDP cells. Altogether, these results have meaningful implications for tumor therapy in the future.
PubMed: 28969040
DOI: 10.18632/oncotarget.19201 -
Cancer Medicine Nov 2017Malignant pleural mesothelioma (MPM), an asbestos-related occupational disease, is an aggressive and incurable tumor of the thoracic cavity. Despite recent advances in...
Malignant pleural mesothelioma (MPM), an asbestos-related occupational disease, is an aggressive and incurable tumor of the thoracic cavity. Despite recent advances in MPM treatment, overall survival of patients with MPM is very low. Recent studies have implicated that PI3K/Akt signaling is involved in MPM cell survival and development. To investigate the effects of Akt inhibitors on MPM cell survival, we examined the effects of nine selective Akt inhibitors, namely, afuresertib, Akti-1/2, AZD5363, GSK690693, ipatasertib, MK-2206, perifosine, PHT-427, and TIC10, on six MPM cell lines, namely, ACC-MESO-4, Y-MESO-8A, MSTO-211H, NCI-H28, NCI-H290, and NCI-H2052, and a normal mesothelial cell line MeT-5A. Comparison of IC values of the Akt inhibitors showed that afuresertib, an ATP-competitive specific Akt inhibitor, exerted tumor-specific effects on MPM cells. Afuresertib significantly increased caspase-3 and caspase-7 activities and apoptotic cell number among ACC-MESO-4 and MSTO-211H cells. Moreover, afuresertib strongly arrested the cell cycle in the G phase. Western blotting analysis showed that afuresertib increased the expression of p21 and decreased the phosphorylation of Akt substrates, including GSK-3β and FOXO family proteins. These results suggest that afuresertib-induced p21 expression promotes G phase arrest by inducing FOXO activity. Furthermore, afuresertib significantly enhanced cisplatin-induced cytotoxicity. Interestingly, results of gene set enrichment analysis showed that afuresertib modulated the expression E2F1 and MYC, which are associated with fibroblast core serum response. Together, these results suggest that afuresertib is a useful anticancer drug for treating patients with MPM.
Topics: Antineoplastic Agents; Apoptosis; Benzylamines; Caspase 3; Caspase 7; Cell Line, Tumor; Cyclin-Dependent Kinase Inhibitor p21; Forkhead Box Protein O1; G1 Phase Cell Cycle Checkpoints; Gene Expression Regulation, Neoplastic; Glycogen Synthase Kinase 3 beta; Heterocyclic Compounds, 3-Ring; Heterocyclic Compounds, 4 or More Rings; Humans; Imidazoles; Inhibitory Concentration 50; Mesothelioma; Oxadiazoles; Phosphorylation; Phosphorylcholine; Pleural Neoplasms; Protein Kinase Inhibitors; Proto-Oncogene Proteins c-akt; Pyrazoles; Pyridines; Pyrimidines; Pyrroles; Quinoxalines; Sulfonamides; Thiadiazoles; Thiophenes
PubMed: 28960945
DOI: 10.1002/cam4.1179 -
Investigational New Drugs Dec 2017Objective Perifosine exhibits anti-tumor activity by inhibiting AKT phosphorylation. The purpose of this phase II basket trial was to evaluate the efficacy and safety of...
Objective Perifosine exhibits anti-tumor activity by inhibiting AKT phosphorylation. The purpose of this phase II basket trial was to evaluate the efficacy and safety of perifosine monotherapy for ovarian, endometrial, and cervical cancers. Methods Recurrent or persistent ovarian, endometrial, or cervical cancer patients were assigned to PIK3CA wild-type or mutant groups. Each patient received 600 mg oral perifosine on day 1 followed by a maintenance dose of 100 mg daily. The primary endpoint was disease control rate; secondary endpoints included response rate, progression-free survival, overall survival, and safety. Immunohistochemical staining and targeted sequencing were used to explore new biomarkers in such patients. Results Sixteen and 5 ovarian, 17 and 7 endometrial, and 18 and 8 cervical cancer patients with PIK3CA wild-type and mutant, respectively, were enrolled. Disease control rates (wild-type/mutant) were 12.5/40.0%, 47.1/14.3%, and 11.1/25.0% in ovarian, endometrial, and cervical cancer, respectively. The most common grade 3/4 toxicities were anemia (22.5%) and anorexia (11.3%). Immunohistochemical staining revealed that the disease control rate in patients with negative phosphatase and tensin homolog (PTEN) expression was 50.0%, and the odds ratio of positive to negative patients was 0.24 in all patients. Conclusions Perifosine monotherapy showed good tolerability but expected efficacy was not achieved. Modest efficacy was demonstrated in ovarian cancer patients with PIK3CA mutations and endometrial cancer patients with PIK3CA wild-type; no difference was observed between PIK3CA wild-type and mutant in cervical cancer. Absence of PTEN expression may be predictive of clinical efficacy with perifosine monotherapy.
Topics: Adult; Aged; Class I Phosphatidylinositol 3-Kinases; Cohort Studies; Female; Follow-Up Studies; Genital Neoplasms, Female; Humans; Middle Aged; Mutation; Neoplasm Recurrence, Local; Phosphorylcholine; Prognosis
PubMed: 28864978
DOI: 10.1007/s10637-017-0504-6 -
PLoS Neglected Tropical Diseases Aug 2017Leishmaniasis is the world's second deadliest parasitic disease after malaria, and current treatment of the different forms of this disease is far from satisfactory....
BACKGROUND
Leishmaniasis is the world's second deadliest parasitic disease after malaria, and current treatment of the different forms of this disease is far from satisfactory. Alkylphospholipid analogs (APLs) are a family of anticancer drugs that show antileishmanial activity, including the first oral drug (miltefosine) for leishmaniasis and drugs in preclinical/clinical oncology trials, but their precise mechanism of action remains to be elucidated.
METHODOLOGY/PRINCIPAL FINDINGS
Here we show that the tumor cell apoptosis-inducer edelfosine was the most effective APL, as compared to miltefosine, perifosine and erucylphosphocholine, in killing Leishmania spp. promastigotes and amastigotes as well as tumor cells, as assessed by DNA breakdown determined by flow cytometry. In studies using animal models, we found that orally-administered edelfosine showed a potent in vivo antileishmanial activity and diminished macrophage pro-inflammatory responses. Edelfosine was also able to kill Leishmania axenic amastigotes. Edelfosine was taken up by host macrophages and killed intracellular Leishmania amastigotes in infected macrophages. Edelfosine accumulated in tumor cell mitochondria and Leishmania kinetoplast-mitochondrion, and led to mitochondrial transmembrane potential disruption, and to the successive breakdown of parasite mitochondrial and nuclear DNA. Ectopic expression of Bcl-XL inhibited edelfosine-induced cell death in both Leishmania parasites and tumor cells. We found that the cytotoxic activity of edelfosine against Leishmania parasites and tumor cells was associated with a dramatic recruitment of FOF1-ATP synthase into lipid rafts following edelfosine treatment in both parasites and cancer cells. Raft disruption and specific FOF1-ATP synthase inhibition hindered edelfosine-induced cell death in both Leishmania parasites and tumor cells. Genetic deletion of FOF1-ATP synthase led to edelfosine drug resistance in Saccharomyces cerevisiae yeast.
CONCLUSIONS/SIGNIFICANCE
The present study shows that the antileishmanial and anticancer actions of edelfosine share some common signaling processes, with mitochondria and raft-located FOF1-ATP synthase being critical in the killing process, thus identifying novel druggable targets for the treatment of leishmaniasis.
Topics: Animals; Antineoplastic Agents; Antiprotozoal Agents; Cell Survival; Cells, Cultured; Disease Models, Animal; Gene Deletion; Humans; Leishmania; Leishmaniasis; Macrophages; Membrane Microdomains; Membrane Potential, Mitochondrial; Mice; Mitochondria; Phospholipid Ethers; Proton-Translocating ATPases; Saccharomyces cerevisiae; Treatment Outcome
PubMed: 28829771
DOI: 10.1371/journal.pntd.0005805