Biphasic regulation by bile acids of dermal fibroblast proliferation through regulation of cAMP production and COX-2 expression level

2006 ◽  
Vol 291 (3) ◽  
pp. C546-C554 ◽  
Author(s):  
Jian Ping Meng ◽  
Susan Ceryak ◽  
Zaheer Aratsu ◽  
Loren Jones ◽  
Lauren Epstein ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Bile Acid ◽  
Bile Acids ◽  
Dermal Fibroblast ◽  
Expression Level ◽  
Dependent Manner ◽  
Fibroblast Proliferation ◽  
Camp Production ◽  
Cox 2 ◽  
Dose Dependent

We have previously reported that the bile acids chenodeoxycholate (CDCA) and ursodeoxycholate (UDCA) decreased PGE1-induced cAMP production in a time- and dose-dependent manner not only in hepatocytes but also in nonhepatic cells, including dermal fibroblasts. In the present study, we investigated the physiological relevance of this cAMP modulatory action of bile acids. PGE1 induced cAMP production in a time- and dose-dependent manner. Moreover, PGE1 (1 μM), forskolin (1–10 μM), and the membrane-permeable cAMP analog CPT-cAMP (0.1–10 μM) decreased dermal fibroblast proliferation in a dose-dependent manner with a maximum inhibition of ∼80%. CDCA alone had no significant effect on cell proliferation at a concentration up to 25 μM. However, CDCA significantly reduced PGE1-induced cAMP production by 80–90% with an EC50 of ∼20 μM. Furthermore, at concentrations ≤25 μM, CDCA significantly attenuated the PGE-1-induced decreased cell proliferation. However, at concentrations of 50 μM and above, while still able to almost completely inhibit PGE-1-induced cAMP production, CDCA, at least in part through an increased cyclooxygenase-2 (COX-2) expression level and PGE2 synthesis, produced a direct and significant decrease in cell proliferation. Indeed, the CDCA effect was partially blocked by ∼50–70% by both indomethacin and dexamethasone. In addition, overexpression of COX-2 cDNA wild type resulted in an increased efficacy of CDCA to block cell proliferation. The effects of CDCA on both cAMP production and cell proliferation were similar to those of UDCA and under the same conditions cholate had no effect. Results of the present study underline pathophysiological consequences of cholestatic hepatobiliary disorders, in which cells outside of the enterohepatic circulation can be exposed to elevated bile acid concentrations. Under these conditions, low bile acid concentrations can attenuate the negative hormonal control on cell proliferation, resulting in the stimulation of cell growth, while at high concentrations these bile acids provide for a profound and prolonged inhibition of cell proliferation.

scholarly journals Sulforaphane induces colorectal cancer cell proliferation through Nrf2 activation in a p53-dependent manner

2020 ◽  
Vol 63 (1) ◽  
Author(s):  
Yunjeong Gwon ◽  
Jisun Oh ◽  
Jong-Sang Kim
Keyword(s):  
Colon Cancer ◽  
Cell Proliferation ◽  
Signaling Pathway ◽  
Cancer Cell ◽  
Related Factor ◽  
Mild Stress ◽  
Dependent Manner ◽  
Cancer Cell Proliferation ◽  
Nrf2 Signaling Pathway ◽  
Dose Dependent

AbstractSulforaphane is a well-known phytochemical that stimulates nuclear factor erythroid 2-related factor 2 (Nrf2)-mediated antioxidant cellular response. In this study, we found that sulforaphane promoted cell proliferation in HCT116 human colon cancer cells expressing a normal p53 gene in a dose-dependent but biphasic manner. Since p53 has been reported to contribute to cell survival by regulating various metabolic pathways to adapt to mild stress, we further examined cellular responses in both p53-wild-type (WT) and p53-knockout (KO) HCT116 cells exposed to sulforaphane in vitro and in vivo. Results demonstrated that sulforaphane treatment activated Nrf2-mediated antioxidant enzymes in both p53-WT and p53-KO cells, decreased apoptotic protein expression in WT cells but increased in KO cells in a dose-dependent manner, and increased the expression of a mitochondrial biogenesis marker PGC1α in WT cells but decreased in KO cells. Moreover, a low dose of sulforaphane promoted tumor growth, upregulated the Nrf2 signaling pathway, and decreased apoptotic cell death in p53-WT HCT116 xenografts compared to that in p53-KO HCT116 xenografts in BALB/c nude mice. These findings suggest that sulforaphane can influence colon cancer cell proliferation and mitochondrial function through a crosstalk between the Nrf2 signaling pathway and p53 axis.

scholarly journals The Olive Leaves Extract Has Anti-Tumor Effects against Neuroblastoma through Inhibition of Cell Proliferation and Induction of Apoptosis

Nutrients ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 2178
Author(s):  
Fabio Morandi ◽  
Veronica Bensa ◽  
Enzo Calarco ◽  
Fabio Pastorino ◽  
Patrizia Perri ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Proliferation ◽  
Cell Viability ◽  
Cell Cycle Progression ◽  
Treatment Strategies ◽  
Annexin V ◽  
Dependent Manner ◽  
Induction Of Apoptosis ◽  
Dose Dependent

Neuroblastoma (NB) is the most common extra-cranial solid tumor of pediatric age. The prognosis for high-risk NB patients remains poor, and new treatment strategies are desirable. The olive leaf extract (OLE) is constituted by phenolic compounds, whose health beneficial effects were reported. Here, the anti-tumor effects of OLE were investigated in vitro on a panel of NB cell lines in terms of (i) reduction of cell viability; (ii) inhibition of cell proliferation through cell cycle arrest; (iii) induction of apoptosis; and (iv) inhibition of cell migration. Furthermore, cytotoxicity experiments, by combining OLE with the chemotherapeutic topotecan, were also performed. OLE reduced the cell viability of NB cells in a time- and dose-dependent manner in 2D and 3D models. NB cells exposed to OLE underwent inhibition of cell proliferation, which was characterized by an arrest of the cell cycle progression in G0/G1 phase and by the accumulation of cells in the sub-G0 phase, which is peculiar of apoptotic death. This was confirmed by a dose-dependent increase of Annexin V+ cells (peculiar of apoptosis) and upregulation of caspases 3 and 7 protein levels. Moreover, OLE inhibited the migration of NB cells. Finally, the anti-tumor efficacy of the chemotherapeutic topotecan, in terms of cell viability reduction, was greatly enhanced by its combination with OLE. In conclusion, OLE has anti-tumor activity against NB by inhibiting cell proliferation and migration and by inducing apoptosis.

scholarly journals Biochemical and biological activity of arginine deiminase from Streptococcus pyogenes M22

2016 ◽  
Vol 94 (2) ◽  
pp. 129-137 ◽  
Author(s):  
Eleonora A. Starikova ◽  
Alexey V. Sokolov ◽  
Anna Yu. Vlasenko ◽  
Larisa A. Burova ◽  
Irina S. Freidlin ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Endothelial Cells ◽  
Streptococcus Pyogenes ◽  
Group A Streptococcus ◽  
Bacterial Pathogen ◽  
Arginine Deiminase ◽  
Dependent Manner ◽  
Group A ◽  
Micro Organisms ◽  
Dose Dependent

Streptococcus pyogenes (group A Streptococcus; GAS) is an important gram-positive extracellular bacterial pathogen responsible for a number of suppurative infections. This micro-organism has developed complex virulence mechanisms to avoid the host’s defenses. We have previously reported that SDSC from GAS type M22 causes endothelial-cell dysfunction, and inhibits cell adhesion, migration, metabolism, and proliferation in a dose-dependent manner, without affecting cell viability. This work aimed to isolate and characterize a component from GAS type M22 supernatant that suppresses the proliferation of endothelial cells (EA.hy926). In the process of isolating a protein possessing antiproliferative activity we identified arginine deiminase (AD). Further study showed that this enzyme is most active at pH 6.8. Calculating Km and Vmax gave the values of 0.67 mmol·L–1 and 42 s−1, respectively. A distinctive feature of AD purified from GAS type M22 is that its optimum activity and the maximal rate of the catalytic process is close to neutral pH by comparison with enzymes from other micro-organisms. AD from GAS type M22 suppressed the proliferative activity of endothelial cells in a dose-dependent mode. At the same time, in the presence of AD, the proportion of cells in G0/G1 phase increased. When l-Arg was added at increasing concentrations to the culture medium containing AD (3 μg·mL–1), the enzyme’s capacity to inhibit cell proliferation became partially depressed. The proportion of cells in phases S/G2 increased concomitantly, although the cells did not fully recover their proliferation activity. This suggests that AD from GAS type M22 has potential for the suppression of excessive cell proliferation.

P–543 Inhibition of cell proliferation and extracellular matrix formation in human uterine leiomyomas by 5-aza–2’-deoxycitidine via Wnt/ β-catenin pathway

2021 ◽  
Vol 36 (Supplement_1) ◽  
Author(s):  
M C Carbajo-García ◽  
A Corachán ◽  
M Segura ◽  
J Monleón ◽  
J Escrig ◽  
...  
Keyword(s):  
Gene Expression ◽  
Dna Methylation ◽  
Extracellular Matrix ◽  
Cell Proliferation ◽  
Protein Expression ◽  
Hormonal Treatment ◽  
Dependent Manner ◽  
Dnmt Inhibitors ◽  
Qrt Pcr ◽  
Dose Dependent

Abstract Study question Is DNA methylation reversion through DNA methyltransferases (DNMT) inhibitors, such as 5-aza–2’-deoxycitidine, a potential therapeutic option for treatment of patients with uterine leiomyomas (UL)? Summary answer 5-aza–2’-deoxycitidine reduces proliferation and extracellular matrix (ECM) formation by inhibition of Wnt/ β-catenin pathway on UL cells, suggesting DNMT inhibitors as an option to treat UL. What is known already: UL is a multifactorial disease with an unclear pathogenesis and inaccurate treatment. Aberrant DNA methylation have been found in UL compared to myometrium (MM) tissue, showing hypermethylation of tumor suppressor genes, which contributes to the development of this tumor. The use of DNMT inhibitors, such as 5-aza–2’-deoxycytidine (5-aza-CdR), has been suggested to treat tumors in which altered methylation pattern is related to tumor progression, as occurs in UL. Based on this, we aimed to evaluate whether DNA methylation reversion through 5-aza-CdR reduces cell proliferation and ECM formation in UL cells, being a potential option for UL medical treatment. Study design, size, duration Prospective study comparing UL versus MM tissue and human uterine leiomyoma primary (HULP) cells treated with/without 5-aza-CdR at 0 µM (control), 2 µM, 5 µM and 10 µM for 72 hours. UL and MM tissue were collected from women without any hormonal treatment for the last 3 months (n = 16) undergoing myomectomy or hysterectomy due to symptomatic leiomyoma pathology. Participants were recruited between January 2019 and February 2020 at Hospital Universitario y Politecnico La Fe (Spain). Participants/materials, setting, methods Samples were collected from Caucasian premenopausal women aged 31–48 years, with a body mass index of < 30 and without hormonal treatment. DNMT1 gene expression was analysed in UL vs MM tissue by qRT-PCR and activity of DNMT was measured in UL and MM tissue and cells by ELISA. 5-aza-CdR effect on proliferation was assessed by CellTiter test and Western blot (WB), apoptosis and ECM analyzed by WB and Wnt/ β-catenin pathway by qRT-PCR and WB. Main results and the role of chance: DNMT1 gene expression was increased in UL compared to MM tissue (fold change [FC]=2.49, p-value [p]=0.0295). Similarly, DNMT activity was increased in both UL compared to MM tissue and HULP cells versus MM cells (6.50 vs 3.76 OD/h/mg, p = 0.026; 211.30 vs 63.67 OD/h/mg, p = 0.284, respectively). After 5-aza-CdR treatment, cell viability of HULP cells was reduced in a dose dependent manner, being statistically significant at 10 µM (85.25%, p = 0.0001). Accordantly, PCNA protein expression was significantly decreased at 10 µM in HULP cells (FC = 0.695, p = 0.034), demonstrating cell proliferation inhibition. Additionally, 5-aza-CdR inhibited ECM protein expression in HULP cells in a dose-dependent manner being statistically significant at 10 µM for COLLAGEN I (FC = 0.654, p = 0.023) and PAI–1 (FC = 0.654, p = 0.023), and at 2 µM and 10 µM for FIBRONECTIN (FC = 0.812, p = 0.020; FC = 0.733, p = 0.035; respectively). Final targets of Wnt/ β-catenin pathway were decreased after 5-aza-CdR treatment, protein expression of WISP1 was significantly inhibited at 10 µM (FC = 0.699, p = 0.026), while expression levels of Wnt/ β-catenin target genes C-MYC (FC = 0.745, p = 0.028 at 2 µM; FC = 0.728, p = 0.019 at 10 µM) and MMP7 (FC = 0.520, p = 0.003 at 5 µM, FC = 0.577, p = 0.007 at 10 µM) were also significantly downregulated in HULP-treated cells vs untreated cells. Limitations, reasons for caution: This study has strict inclusion criteria to diminish epigenetic variability, thereby we should be cautious extrapolating our results to general population. Besides, this is a proof of concept with the inherent cell culture limitations. Further studies are necessary to determine 5-aza-CdR dose and adverse effects on UL in vivo. Wider implications of the findings: 5-aza-CdR treatment reduces cell proliferation and ECM formation through Wnt/ β-catenin pathway inhibition, suggesting that inhibition of DNA methylation could be a promising new therapeutic approach to treat UL. Trial registration number Not applicable

scholarly journals Hif-1α Inhibitors Could Successfully Inhibit the Progression of Differentiated Thyroid Cancer in Vitro

2020 ◽  
Vol 13 (9) ◽  
pp. 208
Author(s):  
Min-Hee Kim ◽  
Tae Hyeong Lee ◽  
Jin Soo Lee ◽  
Dong-Jun Lim ◽  
Peter Chang-Whan Lee
Keyword(s):  
Cell Proliferation ◽  
Thyroid Cancer ◽  
Cell Lines ◽  
Cancer Progression ◽  
Hypoxia Inducible Factor ◽  
Soft Agar ◽  
Dependent Manner ◽  
Thyroid Cancer Cell Lines ◽  
Dose Dependent

Hypoxia-inducible factor (HIF)-1α plays an important role in cancer progression. In various cancers, including thyroid cancer, overexpression of HIF-1α is related to poor prognosis or treatment response. However, few studies have investigated the role of HIF-1α inhibition in thyroid cancer progression. We evaluated the utility of the HIF-1α inhibitor IDF-11774 in vitro utilizing two thyroid cancer cell lines, K1 and BCPAP. Both cell lines were tested to elucidate the effects of IDF-11774 on cell proliferation and migration using soft agar and invasion assays. Here, we found that a reduction of HIF-1α expression in BCPAP cells was observed after treatment with IDF-11774 in a dose-dependent manner. Moreover, cell proliferation, migration, and anchorage-independent growth were effectively inhibited by IDF-11774 in BCPAP cells but not in K1 cells. Additionally, invasion of BCPAP but not K1 cells was controlled with IDF-11774 in a dose-dependent manner. Our findings suggest that promoting the degradation of HIF-1α could be a strategy to manage progression and that HIF-1α inhibitors are potent drugs for thyroid cancer treatment.

scholarly journals Anti-inflammatory Potential of Silk Sericin

2013 ◽  
Vol 8 (4) ◽  
pp. 1934578X1300800 ◽  
Author(s):  
Pornanong Aramwit ◽  
Pasarapa Towiwat ◽  
Teerapol Srichana
Keyword(s):  
Negative Control ◽  
Dependent Manner ◽  
Silk Sericin ◽  
Plantar Surface ◽  
Cox 2 ◽  
Anti Inflammatory ◽  
The Right ◽  
Dose Dependent ◽  
Control Water

Silk sericin was found to suppress the production of pro-inflammatory cytokines, which are related to the inflammatory reaction. The objectives of this study were to investigate the anti-inflammatory effect of sericin in vivo using the carrageenan-induced rat edema model and changes in the histology of tissues. The effects of sericin on the expression of COX-2 and iNOS were also evaluated. Sericin solutions at 0.004-0.080 mg/mL were applied topically to the top of the hind paw and carrageenan (1.0 mg) was injected subcutaneously to the plantar surface of the right hind paw. Our results indicated that sericin significantly reduced the inflammation in rats’ paw compared with the negative control (water and acetone) and its effect at 0.080 mg/mL was only slightly lower than that of 1.0% w/v indomethacin. Similar numbers of polymorphonuclear and macrophage cells were found in rats’ tissue treated with indomethacin and sericin solution, while the numbers were significantly higher in their absence. The gene expression results by RT-PCR showed that the COX-2 and iNOS genes were down-regulated in samples treated with sericin in a dose dependent manner. These data indicated that the anti-inflammatory properties of sericin may be partly attributable to the suppression of the COX-2 enzyme and nitric oxide production.

scholarly journals Inhibitors of Mitogen-Activated Protein Kinases Downregulate COX-2 Expression in Human Chondrocytes

2005 ◽  
Vol 2005 (5) ◽  
pp. 249-255 ◽  
Author(s):  
Riina Nieminen ◽  
Sari Leinonen ◽  
Aleksi Lahti ◽  
Katriina Vuolteenaho ◽  
Ulla Jalonen ◽  
...  
Keyword(s):  
Mrna Expression ◽  
Proinflammatory Cytokine ◽  
Negative Control ◽  
Human Chondrocytes ◽  
Dependent Manner ◽  
Drug Concentrations ◽  
Mitogen Activated Protein ◽  
Cox 2 ◽  
Control Compound ◽  
Dose Dependent

Inducible prostaglandin synthase (cyclooxygenase-2, COX-2) is expressed in rheumatoid and osteoarthritic cartilage and produces high amounts of proinflammatory prostanoids in the joint. In the present study we investigated the effects of the inhibitors of mitogen-activated protein kinase (MAPK) pathways Erk1/2, p38, and JNK on COX-2 expression and prostaglandin E2(PGE2) production in human chondrocytes. Proinflammatory cytokine IL-1βcaused a transient activation of Erk1/2, p38, and JNK in immortalized human T/C28a2 chondrocytes and that was followed by enhanced COX-2 expression and PGE2production. PD98059 (an inhibitor of Erk1/2 pathway) suppressed IL-1-induced COX-2 expression and PGE2production in a dose-dependent manner, and seemed to have an inhibitory effect on COX-2 activity. SB203580 (an inhibitor of p38 pathway) but not its negative control compound SB202474 inhibited COX-2 protein and mRNA expression and subsequent PGE2synthesis at micromolar drug concentrations. SP600125 (a recently developed JNK inhibitor) but not its negative control compound N1-methyl-1,9-pyrazolanthrone downregulated COX-2 expression and PGE2formation in a dose-dependent manner. SP600125 did not downregulate IL-1-induced COX-2 mRNA expression when measured 2 h after addition of IL-1βbut suppressed mRNA levels in the later time points suggesting post-transcriptional regulation. Our results suggest that activation of Erk1/2, p38, and JNK pathways belongs to the signaling cascades that mediate the upregulation of COX-2 expression and PGE2production in human chondrocytes exposed to proinflammatory cytokine IL-1β.

MK886 Induced Apoptosis in HL-60 Cells Via Inhibition mPGES-1 Expression and Down-Regulation Prostaglandin E2 Synthesize.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 4824-4824
Author(s):  
Yiqing Li ◽  
Songmei Yin ◽  
Shuangfeng Xie ◽  
Danian Nie ◽  
Liping Ma ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Protein Expression ◽  
Prostaglandin E2 ◽  
Cell Line ◽  
Caspase 3 ◽  
Leukemia Cell ◽  
Leukemia Cell Line ◽  
Dependent Manner ◽  
Pge2 Synthesis ◽  
Dose Dependent

Abstract Abstract 4824 Recent studies have shown that prostaglandin E2 (PGE2) may play a key role in the tumorigenesis and tumor development. Membrane-bound prostaglandin E2 synthase-1 (mPGES-1), an inducible enzyme that acts downstream of cyclooxygenase (COX) and specifically catalyzes the conversion of prostaglandin H2 (PGH2) to PGE2, was over-expression in a variety of solid tumor cells and tissues such as nonsmall-cell lung cancer, colon carcinoma, gastric carcinoma and breast cancer. MK886, a small molecular inhibitor, is a reasonable potency as an inhibitor of mPGES-1 in vitro experiment. In this study, we examined effects of MK886 on expression of mPGES-1 and PGE2 synthesis in human acute myeloid leukemia cell line (HL-60), observed cell proliferation and apoptosis after 24-h treatment with MK886, and tried to explore the possible mechanisms by checking some protein belong AKT cell singling pathway such as P-AKT, Bax and Bcl-2. We found that the expression levels of mPGES-1 mRNA and protein were higher in HL-60 cells than in normal mononuclearcells (MNC). MK886 inhibited mPGES-1 mRNA and protein expression and reduced PGE2 secretion in HL-60 cells in a dose-dependent manner. The cell proliferation was inhibited and the IC50 was 132.16μmol/L. With the increase of MK886 concentration, the cell apoptosis rate assayed by flow cytometry increased and the apparent apoptotic bodies increased when staining by Hoechst 33258. After treated with MK886 for 24h, protein was extracted and assayed by western blot. The results showed that the expression levels of P-AKT, Bcl-2 and c-myc decreased while the Bax protein expression increased in a dose-dependent manner. The caspase-3 activity, determined by colorimetric detection, also increased dose-dependently. These results indicated that mPGES-1 over-expressed in leukemia cell line HL-60, MK886 could induce apoptosis in HL-60 cells via reducing mPGES-1 expression and PGE2 synthesis dose-dependently, thereby regulate the AKT pathway including Bcl-2 family and the activity of caspase-3. It suggested that mPGES-1 inhibitor might emerge as an important therapeutic tool for leukemia treatment. Disclosures: No relevant conflicts of interest to declare.

Multikinase Inhibitor Sorafenib Induces Apoptosis, CD138-Downregulation, Actin Depolymerization and Inhibition of M210B4-Triggered Chemotaxis in Multiple Myeloma Cell Lines and Synergyzes with Proteasome Inhibitor Bortezomib

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 2380-2380
Author(s):  
Josefina Udi ◽  
Dagmar Wider ◽  
Julie Catusse ◽  
Dominik Schnerch ◽  
Marie Follo ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
Flow Cytometry ◽  
Cell Proliferation ◽  
Actin Polymerization ◽  
Combination Index ◽  
Dependent Manner ◽  
Multikinase Inhibitor ◽  
And Migration ◽  
Dose Dependent ◽  
Morphologic Changes

Abstract Abstract 2380 Introduction: Sorafenib is an oral multikinase inhibitor that targets several cancer-specific pathways and directly affects tumor cell proliferation, cell survival and neovascularization. The Ras/Raf/MEK/ERK pathway is particularly known to be critical for proliferation of multiple myeloma (MM) cells. Moreover, its blockage may not only compromise MM cell survival and proliferation, but also influence cell adhesion and migration. We sought to elucidate the effects of sorafenib on proliferation, phenotype, specific signalling pathways, actin polymerization and chemotaxis, as well as cytotoxic interactions when combined with other anti-MM agents, such as bortezomib. Methods: L363, U266 and RPMI8226 were cultured with RPMI1640, 10% FCS and 0.2% penicillin/streptomycin. On day 0, cells were treated with increasing concentrations of sorafenib and/or bortezomib. Cell viability and cytotoxicity were assessed on days 3 and 6, in addition to day 1 or 2 in previous analyses. The cytotoxic effect for sorafenib and bortezomib combined was evaluated using Calcusyn Software, whereby a combination index =1, <1 or >1 indicated additive, synergistic and antagonistic effects, respectively. CD138 expression and morphologic changes were evaluated via flow cytometry, immunocytochemistry and confocal microscopy. The effect of sorafenib on ERK1/2 phosphorylation was investigated by western blot. Actin polymerization was studied by flow cytometry after labeling with FITC-phalloidin. Chemokine receptor expression was assessed by flow cytometry and chemotaxis of L363 cells with various chemoattractants was studied using 96-well chemotaxis chambers. Results: Our MM-in vitro model confirmed potent cytotoxicity for sorafenib single use and synergistic effects when combined with bortezomib. With 10 and 100μM sorafenib in L363, we observed increased median PI+ cells (62% and 94% on d3, respectively) compared to the control (median PI+ d0: 11%), with similar increases on d6 (median 81% and 92%, respectively). Combined sorafenib and bortezomib use showed additive effects and synergism at 10μM and 10nM bortezomib (combination index: 0.80). Similar to PI-results, viable cells and CD138 expression by flow cytometry substantially decreased with sorafenib in a dose- and time-dependent manner. Regarding the effects on the MAPK pathway, after incubating L363 cells with 1 and 10μM sorafenib for 6 and 24 hours, a dose-dependent downregulation of ERK1/2 phosphorylation was observed. After 3 days of incubation with increasing concentrations of sorafenib, MM cells were stained with DAPI, Phalloidin-Alexa594 and CD138-FITC and analyzed via confocal microscopy. L363 cells highly expressed CD138 in the absence of sorafenib. Of note, sorafenib not only affected cell proliferation, but also phenotype, morphology, actin metabolism and chemotaxis of MM cells. With sorafenib concentrations as low as 1μM, CD138 was downregulated and impressive morphologic changes with a reduction in F-actin content were observed. We could show CXCL12-stimulated actin polymerization and after treatment with sorafenib with concentrations of 10μM and 100μM its inhibition, as confirmed via flow cytometry after labeling with phalloidin-FITC. L363 cells showed high expression of the chemokine receptors CCR4 and CCR5 and underwent chemotaxis to their common ligand CCL5. Chemotaxis of L363 cells was even more evident with the use of supernatant from M210B4 bone marrow stromal cells. This M210B4-induced chemotaxis also occurred in the presence of the specific CXCR4-inhibitor AMD3100, supporting the involvement of chemokines other than CXCL12 in M210B4-induced MM cell migration. M210B4-triggered chemotaxis was substantially inhibited after 3 days of incubation with increasing concentrations of sorafenib in a dose-dependent manner. Conclusions: To the best of our knowledge this is the first analysis of the effects of sorafenib on phenotype, morphology, actin polymerization and migration of MM cells. Sorafenib induced down-regulation of phospho-ERK appeared responsible for the observed actin depolymerization and reduction in M210B4-triggered chemotaxis. Hence, further analysis of sorafenib and other novel anti-MM agents, both in MM cells and their microenvironment, should enable greater progress in this hematopoietic disease. Disclosures: No relevant conflicts of interest to declare.

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