- Metabolic adaptation of airway smooth muscle cells to a SPHK2 substrate precedes cytostasis. [Journal Article]
- AJAm J Respir Cell Mol Biol 2019 Jun 27
- Thickening of the airway smooth muscle is central to bronchial hyperreactivity. We have shown that the sphingosine analog AAL-R can reverse pre-established airway hyperreactivity in a chronic asthma …
Thickening of the airway smooth muscle is central to bronchial hyperreactivity. We have shown that the sphingosine analog AAL-R can reverse pre-established airway hyperreactivity in a chronic asthma model. Since sphingosine analogs can be metabolized by sphingosine kinase 2, we investigated whether this enzyme was required for AAL-R to perturb mechanisms sustaining airway smooth muscle cell proliferation. We found that AAL-R pre-treatment reduced the capacity of live airway smooth muscle cells to use oxygen for oxidative phosphorylation and increased lactate dehydrogenase activity. We also determined that sphingosine kinase 2 was upregulated in airway smooth muscle cells bearing the proliferation marker Ki67, relative to their Ki67-negative counterpart. Comparing different stromal cell subsets of the lung, we found that high sphingosine kinase 2 levels were associated with the ability of AAL-R to inhibit metabolic activity assessed by conversion of the tetrazolium dye MTT. Knock down or pharmacologic inhibition of sphingosine kinase 2 reversed the effect of AAL-R on MTT conversion, indicating the essential role for this kinase in the metabolic perturbations induced by sphingosine analogs. Our results support the hypothesis that increased sphingosine kinase 2 levels in proliferating airway smooth muscle cells could be exploited to counteract airway smooth muscle thickening with synthetic substrates.
- Mutagenic and cytostatic activities of the Xylopia laevigata essential oil in human lymphocytes. [Journal Article]
- NPNat Prod Res 2019 Jun 14; :1-4
- Hydro-distilled essential oil from leaves of Xylopia laevigata was characterized by GC-MS. Twenty-seven components were identified and the oil's major constituents comprised germacrene D, bicyclogerm…
Hydro-distilled essential oil from leaves of Xylopia laevigata was characterized by GC-MS. Twenty-seven components were identified and the oil's major constituents comprised germacrene D, bicyclogermacrene, (E)-caryophyllene and germacrene B. The cytotoxicity of the essential oil of X. laevigata (EOXL), determined by MTT and mitotic index methods in cultured human lymphocytes was observed in all tested concentrations. Cultures treated with EOXL demonstrated significant increase in the frequencies of micronuclei in the cytokinesis-block micronucleus assay (CBMN) and reduction of the cytokinesis-block proliferation index (CBPI) rates. Results demonstrated the cytostatic and mutagenic effects of EOXL, the latter for the first time.
- TGF-β-Mediated Epithelial-Mesenchymal Transition and Cancer Metastasis. [Review]
- IJInt J Mol Sci 2019 Jun 05; 20(11)
- Transforming growth factor β (TGF-β) is a secreted cytokine that regulates cell proliferation, migration, and the differentiation of a plethora of different cell types. Consistent with these findings…
Transforming growth factor β (TGF-β) is a secreted cytokine that regulates cell proliferation, migration, and the differentiation of a plethora of different cell types. Consistent with these findings, TGF-β plays a key role in controlling embryogenic development, inflammation, and tissue repair, as well as in maintaining adult tissue homeostasis. TGF-β elicits a broad range of context-dependent cellular responses, and consequently, alterations in TGF-β signaling have been implicated in many diseases, including cancer. During the early stages of tumorigenesis, TGF-β acts as a tumor suppressor by inducing cytostasis and the apoptosis of normal and premalignant cells. However, at later stages, when cancer cells have acquired oncogenic mutations and/or have lost tumor suppressor gene function, cells are resistant to TGF-β-induced growth arrest, and TGF-β functions as a tumor promotor by stimulating tumor cells to undergo the so-called epithelial-mesenchymal transition (EMT). The latter leads to metastasis and chemotherapy resistance. TGF-β further supports cancer growth and progression by activating tumor angiogenesis and cancer-associated fibroblasts and enabling the tumor to evade inhibitory immune responses. In this review, we will consider the role of TGF-β signaling in cell cycle arrest, apoptosis, EMT and cancer cell metastasis. In particular, we will highlight recent insights into the multistep and dynamically controlled process of TGF-β-induced EMT and the functions of miRNAs and long noncoding RNAs in this process. Finally, we will discuss how these new mechanistic insights might be exploited to develop novel therapeutic interventions.
- Rac-GTPase promotes fibrotic TGF-β1 signaling and chronic kidney disease via EGFR, p53, and Hippo/YAP/TAZ pathways. [Journal Article]
- FJFASEB J 2019 May 16; :fj201802489RR
- Rac-GTPases are major regulators of cytoskeletal remodeling and their deregulation contributes to numerous pathologies. Whether or how Rac promotes tubulointerstitial fibrosis and chronic kidney dise…
Rac-GTPases are major regulators of cytoskeletal remodeling and their deregulation contributes to numerous pathologies. Whether or how Rac promotes tubulointerstitial fibrosis and chronic kidney disease (CKD) is currently unknown. We showed that the major profibrotic cytokine, TGF-β1 promoted rapid Rac1-GTP loading in human kidney 2 (HK-2) human renal epithelial cells. A Rac-specific chemical inhibitor, EHT 1864, blocked TGF-β1-induced fibrotic reprogramming in kidney epithelial cells and fibroblasts. Stable Rac1 depletion in HK-2 cells, moreover, eliminated TGF-β1-mediated non-SMAD pathway activation [e.g., Src, epidermal growth factor receptor (EGFR), p53] and subsequent plasminogen activator inhibitor-1 (PAI-1), connective tissue growth factor, fibronectin, and p21 induction. Rac1 and p22phox knockdown abrogated free radical generation by TGF-β1 in HK-2 cells, consistent with the role of Rac1 in Nicotinamide adenine dinucleotide phosphate oxidase signaling. TGF-β1-induced renal epithelial cytostasis was also completely bypassed by Rac1, p22phox, p47phox, and PAI-1 silencing. Rac1b isoform expression was robustly induced in the fibrotic kidneys of mice and humans. Intraperitoneal administration of EHT 1864 in mice dramatically attenuated ureteral unilateral obstruction-driven EGFR, p53, Rac1b, yes-associated protein/transcriptional coactivator with PDZ-binding motif activation/expression, dedifferentiation, cell cycle arrest, and renal fibrogenesis evident in vehicle-treated obstructed kidneys. Thus, the Rac1-directed redox response is critical for TGF-β1-driven epithelial dysfunction orchestrated, in part, via PAI-1 up-regulation. Rac pathway inhibition suppressed renal oxidative stress and maladaptive repair, identifying Rac as a novel therapeutic target against progressive CKD.-Patel, S., Tang, J., Overstreet, J. M., Anorga, S., Lian, F., Arnouk, A., Goldschmeding, R., Higgins, P. J., Samarakoon, R. Rac-GTPase promotes fibrotic TGF-β1 signaling and chronic kidney disease via EGFR, p53, and Hippo/YAP/TAZ pathways.
- An HK2 Antisense Oligonucleotide Induces Synthetic Lethality in HK1-HK2+ Multiple Myeloma. [Journal Article]
- CRCancer Res 2019 May 15; 79(10):2748-2760
- Although the majority of adult tissues express only hexokinase 1 (HK1) for glycolysis, most cancers express hexokinase 2 (HK2) and many coexpress HK1 and HK2. In contrast to HK1+HK2+ cancers, HK1-HK2…
Although the majority of adult tissues express only hexokinase 1 (HK1) for glycolysis, most cancers express hexokinase 2 (HK2) and many coexpress HK1 and HK2. In contrast to HK1+HK2+ cancers, HK1-HK2+ cancer subsets are sensitive to cytostasis induced by HK2shRNA knockdown and are also sensitive to synthetic lethality in response to the combination of HK2shRNA knockdown, an oxidative phosphorylation (OXPHOS) inhibitor diphenyleneiodonium (DPI), and a fatty acid oxidation (FAO) inhibitor perhexiline (PER). The majority of human multiple myeloma cell lines are HK1-HK2+. Here we describe an antisense oligonucleotide (ASO) directed against human HK2 (HK2-ASO1), which suppressed HK2 expression in human multiple myeloma cell cultures and human multiple myeloma mouse xenograft models. The HK2-ASO1/DPI/PER triple-combination achieved synthetic lethality in multiple myeloma cells in culture and prevented HK1-HK2+ multiple myeloma tumor xenograft progression. DPI was replaceable by the FDA-approved OXPHOS inhibitor metformin (MET), both for synthetic lethality in culture and for inhibition of tumor xenograft progression. In addition, we used an ASO targeting murine HK2 (mHK2-ASO1) to validate the safety of mHK2-ASO1/MET/PER combination therapy in mice bearing murine multiple myeloma tumors. HK2-ASO1 is the first agent that shows selective HK2 inhibition and therapeutic efficacy in cell culture and in animal models, supporting clinical development of this synthetically lethal combination as a therapy for HK1-HK2+ multiple myeloma. SIGNIFICANCE: A first-in-class HK2 antisense oligonucleotide suppresses HK2 expression in cell culture and in in vivo, presenting an effective, tolerated combination therapy for preventing progression of HK1-HK2+ multiple myeloma tumors. GRAPHICAL ABSTRACT: http://cancerres.aacrjournals.org/content/canres/79/10/2748/F1.large.jpg.
- Combined Aurora Kinase A (AURKA) and WEE1 Inhibition Demonstrates Synergistic Antitumor Effect in Squamous Cell Carcinoma of the Head and Neck. [Journal Article]
- CCClin Cancer Res 2019 Jun 01; 25(11):3430-3442
- CONCLUSIONS: Combinatorial treatment with adavosertib and alisertib leads to synergistic antitumor effects in in vitro and in vivo HNSCC models. These findings suggest a novel rational combination, providing a promising therapeutic avenue for TP53-mutated cancers.
- Absence of herb-drug interactions of mistletoe with the tamoxifen metabolite (E/Z)-endoxifen and cytochrome P450 3A4/5 and 2D6 in vitro. [Journal Article]
- BCBMC Complement Altern Med 2019 Jan 18; 19(1):23
- CONCLUSIONS: The in vitro results suggest that mistletoe preparations can be used in combination with tamoxifen without the risk of HDIs.
- Transforming growth factor β (TGFβ) induces NUAK kinase expression to fine-tune its signaling output. [Journal Article]
- JBJ Biol Chem 2019 03 15; 294(11):4119-4136
- TGFβ signaling via SMAD proteins and protein kinase pathways up- or down-regulates the expression of many genes and thus affects physiological processes, such as differentiation, migration, cell cycl…
TGFβ signaling via SMAD proteins and protein kinase pathways up- or down-regulates the expression of many genes and thus affects physiological processes, such as differentiation, migration, cell cycle arrest, and apoptosis, during developmental or adult tissue homeostasis. We here report that NUAK family kinase 1 (NUAK1) and NUAK2 are two TGFβ target genes. NUAK1/2 belong to the AMP-activated protein kinase (AMPK) family, whose members control central and protein metabolism, polarity, and overall cellular homeostasis. We found that TGFβ-mediated transcriptional induction of NUAK1 and NUAK2 requires SMAD family members 2, 3, and 4 (SMAD2/3/4) and mitogen-activated protein kinase (MAPK) activities, which provided immediate and early signals for the transient expression of these two kinases. Genomic mapping identified an enhancer element within the first intron of the NUAK2 gene that can recruit SMAD proteins, which, when cloned, could confer induction by TGFβ. Furthermore, NUAK2 formed protein complexes with SMAD3 and the TGFβ type I receptor. Functionally, NUAK1 suppressed and NUAK2 induced TGFβ signaling. This was evident during TGFβ-induced epithelial cytostasis, mesenchymal differentiation, and myofibroblast contractility, in which NUAK1 or NUAK2 silencing enhanced or inhibited these responses, respectively. In conclusion, we have identified a bifurcating loop during TGFβ signaling, whereby transcriptional induction of NUAK1 serves as a negative checkpoint and NUAK2 induction positively contributes to signaling and terminal differentiation responses to TGFβ activity.
- Mechanisms of cell death induced by arginase and asparaginase in precursor B-cell lymphoblasts. [Journal Article]
- AApoptosis 2019; 24(1-2):145-156
- Arginase has therapeutic potential as a cytotoxic agent in some cancers, but this is unclear for precursor B acute lymphoblastic leukaemia (pre-B ALL), the commonest form of childhood leukaemia. We c…
Arginase has therapeutic potential as a cytotoxic agent in some cancers, but this is unclear for precursor B acute lymphoblastic leukaemia (pre-B ALL), the commonest form of childhood leukaemia. We compared arginase cytotoxicity with asparaginase, currently used in pre-B ALL treatment, and characterised the forms of cell death induced in a pre-B ALL cell line 697. Arginase and asparaginase both efficiently killed 697 cells and mature B lymphoma cell line Ramos, but neither enzyme killed normal lymphocytes. Arginase depleted cellular arginine, and arginase-treated media induced cell death, blocked by addition of arginine or arginine-precursor citrulline. Asparaginase depleted both asparagine and glutamine, and asparaginase-treated media induced cell death, blocked by asparagine, but not glutamine. Both enzymes induced caspase cleavage and activation, chromatin condensation and phosphatidylserine exposure, indicating apoptosis. Both arginase- and asparaginase-induced death were blocked by caspase inhibitors, but with different sensitivities. BCL-2 overexpression inhibited arginase- and asparaginase-induced cell death, but did not prevent arginase-induced cytostasis, indicating a different mechanism of growth arrest. An autophagy inhibitor, chloroquine, had no effect on the cell death induced by arginase, but doubled the cell death induced by asparaginase. In conclusion, arginase causes death of lymphoblasts by arginine-depletion induced apoptosis, via mechanism distinct from asparaginase. Therapeutic implications for childhood ALL include: arginase might be used as treatment (but antagonised by dietary arginine and citrulline), chloroquine may enhance efficacy of asparaginase treatment, and partial resistance to arginase and asparaginase may develop by BCL-2 expression. Arginase or asparaginase might potentially be used to treat Burkitt lymphoma.
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- Relationship between periodontal disease and butyric acid produced by periodontopathic bacteria. [Review]
- IRInflamm Regen 2018; 38:23
- CONCLUSIONS: Butyric acid produced by periodontopathic bacteria may promote progress of the periodontal disease state. Butyric acid is known to act as an HDAC inhibitor. Thus, we believe that advanced epigenetic analysis of the effects of butyric acid on gingival fibroblasts will help elucidate the periodontal disease pathology and facilitate discovery of new targets for periodontal disease treatment.