| 1. |
- Castan, Isabelle, et al.
(författare)
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Mechanisms of inhibition of lipolysis by insulin, vanadate and peroxovanadate in rat adipocytes
- 1999
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Ingår i: Biochemical Journal. - 0264-6021. ; 339, s. 281-289
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Tidskriftsartikel (refereegranskat)abstract
- Vanadate and peroxovanadate (pV), potent inhibitors of tyrosine phosphatases, mimic several of the metabolic actions of insulin. Here we compare the mechanisms for the anti-lipolytic action of insulin, vanadate and pV in rat adipocytes. Vanadate (5 mM) and pV (0.01 mM) inhibited lipolysis induced by 0.01-1 microM isoprenaline, vanadate being more and pV less efficient than insulin (1 nM). A loss of anti-lipolytic effect of pV was observed by increasing the concentration of isoprenaline and/or pV. pV induced tyrosine phosphorylation of the insulin receptor and insulin receptor substrate-1 to a greater extent than insulin, whereas vanadate affected these components little if at all. In addition, only a higher concentration (0.1 mM) of pV induced the tyrosine phosphorylation of p85, the 85 kDa regulatory subunit of phosphoinositide 3-kinase (PI-3K). Vanadate activated PI-3K-independent (in the presence of 10 nM isoprenaline) and PI-3K-dependent (in the presence of 100 nM isoprenaline) anti-lipolytic pathways, both of which were found to be independent of phosphodiesterase type 3B (PDE3B). pV (0.01 mM), like insulin, activated PI-3K- and PDE3B-dependent pathways. However, the anti-lipolytic pathway of 0.1 mM pV did not seem to require insulin receptor substrate-1-associated PI-3K and was found to be partly independent of PDE3B. Vanadate and pV (only at 0.01 mM), like insulin, decreased the isoprenaline-induced activation of cAMP-dependent protein kinase. Overall, these results underline the complexity and the diversity in the mechanisms that regulate lipolysis.
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| 2. |
- Davidsson, Sabina, 1972-, et al.
(författare)
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Cutibacterium acnes Induces the Expression of Immunosuppressive Genes in Macrophages and is Associated with an Increase of Regulatory T-Cells in Prostate Cancer
- 2021
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Ingår i: Microbiology Spectrum. - : American Society for Microbiology. - 2165-0497. ; 9:3
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Tidskriftsartikel (refereegranskat)abstract
- Tumors and infectious agents both benefit from an immunosuppressive environment. Cutibacterium acnes (C. acnes) is a bacterium in the normal skin microbiota, which has the ability to survive intracellularly in macrophages and is significantly more common in prostate cancer tissue compared with normal prostate tissue. This study investigated if prostate cancer tissue culture positive for C. acnes has a higher infiltration of regulatory T-cells (Tregs) and if macrophages stimulated with C. acnes induced the expression of immunosuppressive genes that could be linked to an increase of Tregs in prostate cancer. Real-time PCR and enzyme-linked immunosorbent spot assay (ELISA) were used to examine the expression of immunosuppressive genes in human macrophages stimulated in vitro with C. acnes, and associations between the presence of C. acnes and infiltration of Tregs were investigated by statistically analyzing data generated in two previous studies. The in vitro results demonstrated that macrophages stimulated with C. acnes significantly increased their expression of PD-L1, CCL17, and CCL18 mRNA and protein (p ,0.05). In the cohort, Tregs in tumor stroma and tumor epithelia were positively associated with the presence of C. acnes (P = 0.0004 and P = 0.046, respectively). Since the macrophages stimulated with C. acnes in vitro increased the expression of immunosuppressive genes, and prostate cancer patients with prostatic C. acnes infection had higher infiltration of Tregs than their noninfected counterparts, we suggest that C. acnes may contribute to an immunosuppressive tumor environment that is vital for prostate cancer progression.
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| 3. |
- Degerman, Eva, et al.
(författare)
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Phosphorylation and activation of hormone-sensitive adipocyte phosphodiesterase type 3B
- 1998
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Ingår i: Methods. - : Elsevier BV. - 1095-9130 .- 1046-2023. ; 14:1, s. 43-53
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Tidskriftsartikel (refereegranskat)abstract
- Phosphodiesterases (PDEs) include a large group of structurally related enzymes that belong to at least seven related gene families (PDEs 1-7) that differ in their primary structure, affinity for cAMP and cGMP, response to specific effectors, sensitivity to specific inhibitors, and regulatory mechanism. One characteristic of PDE3s involves their phosphorylation and activation in response to insulin as well as to agents that increase cAMP in adipocytes, hepatocytes, and platelets and in response to insulin-like growth factor 1 in pancreatic beta cells. In adipocytes, activation of the membrane-associated PDE3B is the major mechanism whereby insulin antagonizes catecholamine-induced lipolysis. PDE3B activation results in increased degradation of cAMP and, thereby, a lowering of the activity of cAMP-dependent protein kinase (PKA). The reduced activity of PKA leads to a net dephosphorylation and decreased activity of hormone-sensitive lipase and reduced hydrolysis of triglycerides. Activation of the rat adipocyte PDE3B by insulin is associated with phosphorylation of serine-302. The mechanism whereby insulin stimulation leads to phosphorylation/activation of PDE3B is only partly understood. In rat adipocytes, lipolytic hormones and other agents that increase cAMP, including isoproterenol, also induce rapid phosphorylation, presumably catalyzed by PKA, of serine-302 of PDE3B. The phosphorylation is associated with activation of the enzyme, most likely representing "feedback" regulation of cAMP, presumably allowing close coupling of the regulation of steady-state concentrations of both cAMP and PKA and, thereby, control of lipolysis. In the review we describe methods and strategies used in the authors' laboratories to study phosphorylation and activation of PDE3B in adipocytes and in vitro.
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| 4. |
- Engström, Alexander, et al.
(författare)
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Conditioned media from M1 but not M2 macrophage phenotype inhibits proliferation of thr colon cancer cell lines HT29 and CACO-2
- 2013
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Konferensbidrag (refereegranskat)abstract
- BackgroundTumor associated macrophages (TAMs) are often present at a high level in colorectal cancer (CRC) but whether the presence of TAMs in CRC is good or bad is unclear. Macrophages can be categorized into two main subgroups, M1 or M2, that display pro – and anti-inflammatory properties respectively. An improved knowledge of the different macrophage phenotypes will broaden the understanding of their involvement in CRC. We have used an in vitro model to study the effects of human M1 and M2 macrophages on the growth and cell cycle of colon cancer cell lines. MethodHuman monocytes were differentiated into M1 or M2 macrophages and conditioned media was collected. Effects of the conditioned media were measured on the colon cancer cell lines HT-29 and CACO-2 in regards to proliferation, cell cycle distribution and apoptosis. A protein array was used to analyze the released amount of 42 different cytokines from M1 and M2 macrophages into the collected conditioned media. ResultsGrowth arrest was induced in HT-29 and CACO-2 by M1 conditioned media, while M2 conditioned media had no major effect. Analysis of cell cycle distribution and apoptosis in HT-29 cells revealed that treatment with M1 conditioned media on these cells increased apoptosis and caused a disturbed cell cycle with accumulation in G0/G1 and G2/M and a corresponding reduction in S-phase. The protein array revealed several cytokines expressed in M1 with potential inhibitory growth effects. We treated HT-29 cells with two of the candidates, TNF-a and CXCL9, but neither induced growth arrest. ConclusionM1 – but not M2-macrophages had a major inhibitory effect on the growth of the colon cancer cell lines HT-29 and CACO-2 and suggest a role for M1 macrophages in anti-tumor activity and possible favorable outcome for CRC patients.
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| 5. |
- Engström, Alexander, Ph.D, 1987-, et al.
(författare)
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Conditioned media from macrophages of M1, but not M2 phenotype, inhibit the proliferation of the colon cancer cell lines HT-29 and CACO-2
- 2014
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Ingår i: International Journal of Oncology. - Athens, Greece : Spandidos. - 1019-6439 .- 1791-2423. ; 44:2, s. 385-392
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Tidskriftsartikel (refereegranskat)abstract
- Solid tumors are infiltrated by stroma cells including macrophages and these cells can affect tumor growth, metastasis and angiogenesis. We have investigated the effects of conditioned media (CM) from different macrophages on the proliferation of the colon cancer cell lines HT-29 and CACO-2. CM from THP-1 macrophages and monocyte-derived human macrophages of the M1 phenotype, but not the M2 phenotype, inhibited proliferation of the tumor cells in a dose-dependent manner. Lipopolysaccaharide and interferon gamma was used for differentiation of macrophages towards the M1 phenotype and CM were generated both during differentiation (M1(DIFF)) and after differentiation (M1). M1 and M1(DIFF) CM as well as THP-1 macrophage CM resulted in cell cycle arrest in HT-29 cells with a decrease of cells in S phase and an increase in G(2)/M phase. Treatment of HT-29 cells with M1(DIFF), but not M1 or THP-1 macrophage CM, resulted in apoptosis of about 20% of the tumor cells and this was accompanied by lack of recovery of cell growth after removal of CM and subsequent culture in fresh media. A protein array was used to identify cytokines released from M1 and M2 macrophages. Among the cytokines released by M1 macrophages, tumor necrosis factor alpha and CXCL9 were tested by direct addition to HT-29 cells, but neither affected proliferation. Our results indicate that M1 macrophages inhibit colon cancer cell growth and have the potential of contributing to reducing tumor growth in vivo.
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| 6. |
- Göransson, Olga, et al.
(författare)
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Insulin-induced translocation of protein kinase B to the plasma membrane in rat adipocytes
- 1998
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Ingår i: Biochemical and Biophysical Research Communications. - : Elsevier BV. - 1090-2104 .- 0006-291X. ; 246:1, s. 249-254
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Tidskriftsartikel (refereegranskat)abstract
- Protein kinase B (PKB) has previously been shown to be activated in response to insulin and growth factor stimulation. The activation mechanism has been suggested to involve translocation of PKB to membranes, where it is phosphorylated and activated. Insulin-induced translocation of PKB has not been demonstrated in a physiological target cell. Therefore we have used the primary rat adipocyte to investigate insulin-induced translocation of PKB. In the presence of 1 nM insulin translocation of PKB was detected within 30 seconds and was blocked by wortmannin, a selective phosphatidylinositol 3-kinase inhibitor. This translocation was potentiated by the tyrosine phosphatase inhibitor vanadate. Subcellular localization studies revealed that PKB translocated to the plasma membrane.
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| 7. |
- Hedbrant, Alexander, 1987-
(författare)
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Cancer and Inflammation : Role of Macrophages and Monocytes
- 2015
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Macrophages are cells of the innate immune system that can be found in large quantities in cancer tumors and affect cancer progression by regulating growth and invasiveness of cancer cells. There are two main phenotypes of macrophages denoted M1 and M2. In this thesis, the M1 and M2 phenotype of human macrophages were characterized, and effects of the macrophages on the growth and invasiveness of colon and lung cancer cells were studied.Macrophages of the M1 phenotype, but not the M2 phenotype, inhibited growth of both colon and lung cancer cells, and the inhibition for some of the cancer cell lines was induced by cell cycle arrest in the G1/G0 and/or G2/M cell cycle phases. In the colon cancer cell line, the macrophage induced cell cycle arrest was found to attenuate the cytotoxic effect of the chemotherapeutic drug 5-FU. Macrophages were also shown to express high levels of proteases (matrix metalloproteinase-2 and 9) and high levels of proteins of the urokinase-type plasminogen activator (uPA) system, in comparison to the lung cancer cell lines studied. Expression of these has been found to predict poor outcome in lung cancer, and the results suggest macrophages to be important contributors of these in lung tumors. Furthermore, the M1 phenotype was found to express higher levels of the uPA receptor than the M2 phenotype.Prostaglandin E2 (PGE2) is a potent inflammatory molecule expressed by e.g. macrophages and monocytes, and inhibition of its expression has been shown to reduce the risk of colon cancer. Green tea and black tea was found to be potent inhibitors of PGE2 formation in human monocytes, and the inhibitory effects of green tea was likely due to its content of the polyphenol epigallocatechin gallate. Rooibos tea also inhibited PGE2 formation, but was less potent than green and black tea. The primary mechanism for the inhibition was via inhibition of expression of enzymes in the PGE2 formation pathway, and primarily microsomal prostaglandin synthase-1.
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| 8. |
- Hedbrant, Alexander, et al.
(författare)
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Conditioned media from human macrophages of M1 phenotype attenuate the cytotoxic effect of 5-fluorouracil on the HT-29 colon cancer cell line
- 2015
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Ingår i: International Journal of Oncology. - Athens, Greece : Spandidos Publications. - 1019-6439 .- 1791-2423. ; 46:1, s. 37-46
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Tidskriftsartikel (refereegranskat)abstract
- Resistance of tumor cells to chemotherapy, such as 5-fluorouracil (5-FU), is an obstacle for successful treatment of cancer. As a follow-up of a previous study we have investigated the effect of conditioned media (CM) from macrophages of M1 or M2 phenotypes on 5-FU cytotoxicity on the colon cancer cell lines HT-29 and CACO-2. HT-29 cells, but not CACO-2 cells, having been treated with a combination of M1 CM and 5-FU recovered their cell growth to a much larger extent compared to cells having been treated with 5-FU alone when further cultured for 7 days in fresh media. M1 CM treatment of HT-29, but not CACO-2 cells, induced cell cycle arrest in the G(0)/G(1) and G(2)/M phases. 5-FU treatment induced accumulation of cells in S-phase in both HT-29 and CACO-2 cells. This accumulation of cells in S-phase was attenuated by combined M1 CM and 5-FU treatment in HT-29 cells, but not in CACO-2 cells. The mRNA expression of cell cycle regulatory proteins and 5-FU metabolic enzymes were analyzed in an attempt to find possible mechanisms for the M1 CM induced attenuation of 5-FU cytotoxicity in HT-29. Thymidylate synthetase (TS) and thymidine phosphorylase (TP) were found to be substantially downregulated and upregulated, respectively, in HT-29 cells treated with M1 CM, making them unlikely as mediators of reduced 5-FU cytotoxicity. Among cell cycle regulating proteins, p21 was induced in HT-29 cells, but not in CACO-2 cells, in response to M1 CM treatment. However, small interfering RNA (siRNA) knockdown of p21 had no effect on the M1 CM induced cell cycle arrest seen in HT-29 and neither did it change the growth recovery after combined treatment of HT-29 cells with M1 CM and 5-FU. In conclusion, treatment of HT-29 cells with M1 CM reduces the cytotoxic effect of 5-FU and this is mediated by a M1 CM induced cell cycle arrest in the G(0)/G(1) and G(2)/M phases. So far, we lack an explanation why this action is absent in the CACO-2 cells. The current findings may be important for optimization of chemotherapy in colon cancer.
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| 9. |
- Hedbrant, Alexander, Ph.D, 1987-, et al.
(författare)
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Green, Black and Rooibos Tea Inhibit Prostaglandin E2 Formation in Human Monocytes by Inhibiting Expression of Enzymes in the Prostaglandin E2 Pathway
- 2022
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Ingår i: Molecules. - : MDPI. - 1431-5157 .- 1420-3049. ; 27:2
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Tidskriftsartikel (refereegranskat)abstract
- The formation of prostaglandin E2 (PGE2) is associated with adverse inflammatory effects. However, long-term treatment with nonsteroidal anti-inflammatory drugs (NSAIDs) comes with risk of severe side effects. Therefore, alternative ways to inhibit PGE2 are warranted. We have investigated the effects of tea extracts and the polyphenols epigallocatechin gallate (EGCG) and quercetin on PGE2 formation, determined by immunoassay, and protein expression, determined by immunoblotting, of cytosolic phospholipase A2 (cPLA2), cyclooxygenase 2 (COX-2) and microsomal PGE synthase-1 (mPGES-1) in human monocytes. Green and black tea extracts, and with a lower potency, Rooibos tea extract, inhibited lipopolysaccharide (LPS) and calcium ionophore-induced PGE2 formation. In addition, all tea extracts inhibited the LPS-induced expression of mPGES-1, and the green and black tea extracts also inhibited, to a lesser extent, COX-2 expression. The tea extracts only marginally reduced cPLA2 expression and had no effect on COX-1 expression. EGCG, present in green and black tea, and quercetin, present in all three teas, also inhibited PGE2 formation and expression of mPGES-1, COX-2 and cPLA2. Cell-based and cell-free assays were also performed to evaluate direct effects on the enzymatic activity of COX and PGE synthases. Mainly, the cell-free assay demonstrated partial inhibition by the tea extracts and polyphenols. However, the inhibition required higher doses compared to the effects demonstrated on protein expression. In conclusion, green and black tea, and to a lesser extent Rooibos tea, are potent inhibitors of PGE2 formation in human monocytes, and mediate their effects by inhibiting the expression of the enzymes responsible for PGE2 formation, especially mPGES-1.
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| 10. |
- Hedbrant, Alexander, et al.
(författare)
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Macrophages of M1 phenotype have properties that influence lung cancer cell progression
- 2015
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Ingår i: Tumor Biology. - : Springer. - 1010-4283 .- 1423-0380. ; 36:11, s. 8715-8725
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Tidskriftsartikel (refereegranskat)abstract
- Stromal macrophages of different phenotypes can contribute to the expression of proteins that affects metastasis such as urokinase-type plasminogen activator (uPA), its receptor uPAR, and plasminogen activator inhibitor-1 (PAI-1), but knowledge of how essential their contribution is in comparison to the cancer cells in small cell lung cancer (SCLC) and lung squamous cell carcinoma (SCC) is lacking. The expression of uPA, uPAR, and PAI-1 and of the matrix metalloproteinases (MMP)-2 and MMP-9 were studied in human macrophages of M1 and M2 phenotype and compared to a lung SCC (NCI-H520) and a SCLC (NCI-H69) cell line. Effects of treatment with conditioned media (CM) from M1 and M2 macrophages on the expression of these genes in H520 and H69 cells as well as effects on the cell growth were investigated. In addition, data on the stromal macrophages immunoreactivity of uPAR, MMP-2, and MMP-9 in a few SCC and SCLC biopsies was included. uPAR, MMP-2, and MMP-9 were confirmed in stromal cells including macrophages in the SCC and SCLC biopsies. In vitro, both macrophage phenotypes expressed considerably higher mRNA levels of uPA, uPAR, PAI-1, and MMP-9 compared to the cancer cell lines, and regarding uPAR, the highest level was found in the M1 macrophage phenotype. Furthermore, M1 CM treatment not only induced an upregulation of PAI-1 in both H520 and H69 cells but also inhibited cell growth in both cell lines, giving M1 macrophages both tumor-promoting and tumor-killing potential.
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