CXCL12/CXCR4 Axis Drives Mitochondrial Trafficking in Tumor Myeloma Microenvironment

Abstract Mesenchymal stromal cells (MSCs) within the protective microenvironment of multiple myeloma (MM) promote tumor growth, confer chemoresistance and support metabolic needs of plasma cells (PCs) also transferring mitochondria. In this scenario, heterocellular communication and dysregulation of critical signaling axes are among the major contributors to progression and treatment failure. As metabolic rewiring is involved in the regulation of MSC phenotype, we first analyzed metabolic profile of healthy control (HC-) and MM-MSCs. NAD +/NADH ratio was decreased in MM-MSCs (n=8) as compared with HC-MSCs (n=4, p<0.05), meanwhile ATP/ADP ratio was not significantly different between the two groups. This led us to analyze whether MM-MSCs were much prone in transferring mitochondria than HC-MSCs. We first labeled HC- and MM-MSCs with Mitotracker Red CMXRos before co-culture with MM cells. After 24h of coculture, we quantified mitochondria transfer by flow cytometry. The obtained values were significantly higher in MM cells co-cultured with MM-MSCs (n=10) as compared to PCs co-cultured with HC-MSCs (n=5, p<0.01). In the cell-to-cell contact the gap junction-forming protein CX43 has been found critical for mitochondria uptake in lung and brain injury and it also can regulate CXCL12 secretion by MSCs. We found that MM-MSCs showed a significantly up-regulated CXCL12 expression as compared to HC-MSCs (p<0.001). Therefore, we co-cultured HS-5 cells with myeloma cell lines and observed that significantly increased CXCL12-CX43 colocalization in healthy MSCs. To evaluate the selective PC-induced activation of CXCL12 expression via CX43 in MSCs, we co-cultured HS-5 cells with MM cell lines and exposed cocultures to ioxynil octanoate (IO), a selective inhibitor of CX43-based gap junctions. We found that the up-regulation of CXCL12 induced by MM cells was reverted by exposition to the CX43 inhibitor, thereby indicating that CX43 activated by PCs regulates CXCL12 production in MSCs. Given that CX43 is involved in mitochondria trafficking, we subsequently cocultured MM cells with HS-5 in presence or not of IO. Our data showed that mitochondrial transfer was abolished by CX43 inhibitor. Given that MM PCs induced increased CX43 and CXCL12 colocalization in HS-5 cells, we supposed that CXCL12/CXCR4 signaling could regulate mitochondria trafficking throughout this axis. For this reason, we analyzed the kinetic of mitochondria uptake of several HMCLs and related their CXCR4 expression with the percentage of transferred mitochondria. Our data demonstrated that HMCLs with higher expression of CXCR4 had also higher percentage of transferred mitochondria both in time lapse and flow cytometry. The correlation between CXCR4 expression and the percentage of mitochondria uptake in HMCLs was also confirmed in primary myeloma PCs. Furthermore, plerixafor, a selective inhibitor of CXCR4, significantly reduced mitochondrial transfer from MSCs to myeloma PCs further establishing mechanistically that CXCR4/CXCL12 is directly involved in mitochondrial trafficking. Next, we investigated whether combination of plerixafor with bortezomib or carfilzomib interferes with mitochondrial transfer from MSCs to PCs. Interestingly, we found that the proteasome inhibitors promoted mitochondrial transfer while their combination with plerixafor inhibited mitochondria trafficking. Moreover, intracellular expression of CXCR4 in myeloma PCs from BM biopsy specimens demonstrated higher CXCR4 colocalization with CD138+ cells of non-responder patients to bortezomib compared with responder patients, suggesting that CXCR4 mediated chemoresistance in MM. In conclusion, we have shown that MM-MSCs are relatively low dependent on mitochondria metabolism and are inclined to transfer mitochondria to MM tumor cells. Furthermore, tumor PCs increase the expression of CX43 in MSCs leading to an increased levels of CXCL12 and stimulation of its corresponding receptor expressed on MM cells. The resulting CX43/CXCL12/CXCR4 interplay enhances mitochondrial trafficking from MSCs to myeloma PCs and can protect cancer cells against anti-myeloma agents. Understanding pro-tumorigenic phenotype of MSCs and mechanisms of adhesion and heterocellular communication favoring their interaction with cancer PCs, will allow to manipulate critical pathways, including CXCL12/CXCR4 axis, thus improving disease outcome. Disclosures Di Raimondo: Pfizer: Honoraria; AbbVie: Honoraria; Bristol Myers Squibb: Honoraria; Jazz Pharmaceutical: Honoraria; Janssen Pharmaceuticals: Honoraria; Amgen: Honoraria.

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CXCR7 Regulates SDF-1 Induced Adhesion and Homing in Multiple Myeloma.

Blood ◽

10.1182/blood.v112.11.1674.1674 ◽

2008 ◽

Vol 112 (11) ◽

pp. 1674-1674 ◽

Cited By ~ 2

Author(s):

Nicholas Burwick ◽

Anne-Sophie Moreau ◽

Xiaoying Jia ◽

Xavier Leleu ◽

Judith Runnels ◽

...

Keyword(s):

Multiple Myeloma ◽

Bone Marrow ◽

Flow Cytometry ◽

Cell Adhesion ◽

Cell Lines ◽

Cxcr4 Expression ◽

Rt Pcr ◽

Growth And Survival ◽

Tumor Types

Abstract BACKGROUND: Multiple myeloma (MM) is a plasma cell malignancy that depends on interactions with the bone marrow (BM) microenvironment for growth and survival. In turn, adhesion of MM cells to the BM stroma provides a mechanism of resistance from standard chemotherapeutic agents. Recently, our lab has shown that by disrupting this adhesion using a selective CXCR4 inhibitor named AMD3100, MM cells are more sensitive to the proteasome inhibitor Bortezomib (Ghobrial lab, unpublished data). CXCR4 has been a particularly attractive target because its ligand SDF-1 is known to induce p42/44 MAPK, AKT, and the down-stream anti-apoptotic protein bad in MM cells, leading to increased MM growth and survival. Until recently, CXCR4 was thought to be a canonical receptor for the SDF-1 ligand. However, a second chemokine receptor for SDF-1 was subsequently discovered and named CXCR7. CXCR7 is a novel chemokine receptor that is important in cell adhesion, growth and survival in several tumor types. However, the role of CXCR7 in multiple myeloma (MM) has yet to be explored. Furthermore, the ability of SDF-1 ligand to regulate MM function via CXCR7 has not been studied. METHODS: The MM cell lines (U266, MM1.S, RPMI, OPM2, OPM1) were used. After informed consent was obtained, primary bone marrow samples from MM patients were collected. CD138 positive mononuclear cells were isolated by microbead selection. The expression of CXCR7 on MM cell lines and patient samples was confirmed using flow cytometry and RT-PCR analysis. For functional in vitro and ex-vivo assays, the CXCR7 selective antagonist 733 was used (ChemoCentryx Inc., Mountain View, CA). RESULTS: Here we show that CXCR7 was expressed on all tested MM cell lines and primary patient samples as demonstrated by flow cytometry and RT-PCR. Furthermore, CXCR7 was found to regulate SDF-1 induced MM cell adhesion, as demonstrated by in vitro assays using a small molecule compound specific for CXCR7 (733). The CXCR7 antagonist showed significant inhibition of adhesion of MM cell lines and patient samples to fibronectin, endothelial cells and stromal cells, with 50% reduction of adhesion at 5nM of the CXCR7 inhibitor, and with similar activity compared to 20uM of AMD3100 (CXCR4 inhibitor). However, unlike CXCR4, CXCR7 did not effect trans-well migration to SDF-1 chemokine. Interestingly, both receptors were found to be important for trans-endothelial migration of MM cells. Moreover, pre-treatment with 733 reduced homing of MM cells to the BM niche in vivo. Previous studies have failed to show signaling in response to CXCR7 in many tumor types. Here, we demonstrate that treatment with 733 inhibited SDF-1 induced pERK and pAKT, ribosomal pS6Kinase, pGSK3, pSTAT3, pFAK and pPAK signaling pathways, confirming a role for CXCR7 in facilitating SDF-1 signaling. This effect was further confirmed using immunofluorescence. To investigate whether CXCR7 and CXCR4 interact directly, we examined the effect of 733 and AMD3100 on CXCR4 expression and found that AMD3100 significantly inhibited CXCR4 expression, while 733 had no effect on CXCR4 expression, even in the presence of SDF-1. The CXCR7 inhibitor had no effect on the survival of MM cells using MTT and flow cytometry analysis, while high doses of 733 (1uM) had modest inhibition of proliferation. Interestingly, 733 prevented the growth advantage induced by 30nM SDF-1 at 24 hrs. CONCLUSION: Together, these results demonstrate the importance of CXCR7 in regulating MM adhesion and homing, and highlight the differential effects of CXCR4 and CXCR7 in regulating SDF-1 signaling in MM, thus providing a rationale for targeting the SDF-1/CXCR7 axis in MM.

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Bone Marrow Interaction in Multiple Myeloma Pathogenesis: Phenotypical Analysis, Kinetics and Novel Therapy Approaches Based On CXCR4 Inhibition.

Blood ◽

10.1182/blood.v120.21.2450.2450 ◽

2012 ◽

Vol 120 (21) ◽

pp. 2450-2450

Author(s):

Johannes Waldschmidt ◽

Dagmar Wider ◽

Marie Follo ◽

Josefina Udi ◽

Martina Kleber ◽

...

Keyword(s):

Flow Cytometry ◽

Adhesion Molecules ◽

Cell Lines ◽

Cxcr4 Expression ◽

Cell Trafficking ◽

Newly Diagnosed ◽

Infiltration Rates ◽

Dependent Cell ◽

And Migration

Abstract Abstract 2450 Introduction: The interaction between malignant plasma cells and their microenvironment is central in multiple myeloma (MM) pathogenesis. Binding of MM cells to bone marrow (BM) stroma cells triggers the expression of adhesion molecules and secretion of chemo- and cytokines, promoting MM cell growth, drug resistance and migration. Stromal-derived factor-1 (SDF-1) and its receptor CXCR4 are essential for normal hematopoietic progenitor cell movement and adherence within the BM microenvironment. In leukemia and lymphoma, oncoproteins may inhibit SDF-1-dependent cell trafficking within the BM through a mechanism that is not fully understood. For that reason, understanding SDF-1-dependent cell trafficking within the BM and targeting MM-cell - host-BM interactions display a promising approach for the development of novel therapeutic strategies. Methods: BM samples of MM patients (n=59) were analysed using flow cytometry and compared to MGUS patients (n=3) and healthy volunteers (n=7). We compared patient samples with low BM infiltration (≤5%; n=13) intermediate (5–30%; n=29) and high infiltration rates (≥30%; n=17). We also assessed expression of adhesion molecules in MM patients with long-term disease control (n=20) vs. both newly diagnosed (n=16) and symptomatic MM patients (n=23) as previously grouped by San Miguel et al. (Haematologica July 6,2012). We also sought to elucidate in vitro, whether specific anti-MM agents (bortezomib, vorinostat, pomalidomide, EGCG), with and without M210B4 stroma support, and with and without the CXCR4 inhibitor AMD3100, target the interaction of MM cells. Experiments were performed using MM cell lines (U266, RPMI8226, L363, NCI-H929), the control T-cell line MOLT-4 and MM-patient BM samples. Cell viability was assessed via Trypan Blue- and AnnexinV/PI-staining. CD138, CXCR4 (SDF1-receptor), CD49d (VLA-4), CD11a (LFA-1) and CD44 (HERMES antigen) expression was evaluated by flow cytometry and ScanR microscopy. Results: In BM samples of MM patients as compared to MGUS and healthy volunteers, the CXCR4/CD138- (p=.036), CD49d/CD138- (p=.0013) and CD44/CD138-expression (p=.0072) was significantly amplified and correlated with increasing BM infiltration rates (p=.001). Both newly diagnosed and symptomatic MM patients confirmed significantly increased CXCR4/CD138-, CD49d/CD138- (p=.0013) and CD44/CD138-expression as compared to patients with long-term disease control. Of note, in newly diagnosed patients, the expression of adhesion molecules was even more enhanced than in symptomatic myeloma patients, underlining their critical and future potential role as targets for novel therapeutics. Comparison of MM cell lines' adhesion and migration markers with that of MM-patient BM specimens revealed U266 as the cell line most closely resembling human specimens. Cytotoxic effects with use of MM cell lines and bortezomib, vorinostat and pomalidomide confirmed prior cytotoxic concentrations. Cocultivation with stroma substantially reduced apoptosis and induced tumor protective effects. Additional AMD3100 treatment restored sensitivity to bortezomib, vorinostat and pomalidomide. CXCR4 expression was substantially reduced after AMD3100 treatment, while that of CD49d, CD44 and CD11a remained widely unchanged. Toxic or therapeutic effects of AMD3100 monotherapy were excluded for used doses of 50μM. Additional use of ScanR microscopy visualized co-localisation of CXCR4 expression both on the cell surface and within the cytoplasm of MM cells. ScanR microscopy results correlated with flow cytometry-determined CXCR4 expression. Ongoing analyses of both ScanR microscopy and flow cytometry will allow the detailed assessment of treatment studies with and without anti-MM agents and AMD3100. Conclusions: Our findings underline the critical role of adhesion and migration molecules in MM and may pave the way for novel therapeutic approaches targeting these microenvironmental mediators. Disclosures: No relevant conflicts of interest to declare.

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Anti-HLA-DR Monoclonal Antibody Evokes a Novel Non-Apoptotic Cell Death Pathway In Acute Lymphoblastic Leukemia

Blood ◽

10.1182/blood.v116.21.3245.3245 ◽

2010 ◽

Vol 116 (21) ◽

pp. 3245-3245

Author(s):

Khimara Naidoo ◽

Waleed Alduaij ◽

Jamie Honeychurch ◽

Eleanor Cheadle ◽

Seema Alexander ◽

...

Keyword(s):

Monoclonal Antibody ◽

Flow Cytometry ◽

Cell Death ◽

Acute Lymphoblastic Leukemia ◽

Cell Lines ◽

Actin Polymerization ◽

Lymphoblastic Leukemia ◽

Cell Contact ◽

Latrunculin B ◽

Hla Dr

Abstract Abstract 3245 Whilst modern treatment approaches cure a high number of patients with acute lymphoblastic leukemia (ALL), little progress has been made in the treatment of refractory and relapsed ALL and new treatment approaches are needed. We recently demonstrated that anti-HLA-DR class II monoclonal antibody (mAb) L243 induces a novel non-apoptotic mode of cell death in B-cell lymphoma lines, defined by homotypic adhesion (HA), actin reorganisation and lysosomal activity (Ivanov et al. J Clin Invest, 2009). Here, we extend these important observations and examine whether this novel form of mAb induced cell death occurs in pre-B ALL cell lines. Expression of HLA-DR was determined using flow cytometry in a panel of ALL cell lines (REH, SupB15 and SD1). HLA-DR was expressed at high levels on each of the cell lines. The ability of L243 to induce HA and cell death (Annexin V/PI positivity) was assessed using microscopy and flow cytometry respectively. L243 was able to evoke both strong HA and cell death in all of the ALL cell lines (e.g. in SupB15 cells 46±1.7% death versus 7±0.5% in controls, p<0.001 by Student's t-test). Inhibitors of actin polymerization (cytochalasin D, latrunculin B) were used to assess the role of actin in cell death and HA induced by L243. These inhibitors of actin polymerization inhibited both HA and cell death elicited by L243 (e.g. in SupB15 cells 24±0.5% death versus 10.3±0.8% with Latrunculin B, p<0.001), demonstrating the dependence of HA and cell death on actin reorganisation. The importance of cell to cell contact in this form of antibody induced cell death was confirmed by the addition of low-melting point agarose which physically blocked cell to cell contact and markedly attenuated cell death induced by L243. In contrast using the pan-caspase inhibitor QVD OPH had no effect on cell death induced by L243, indicating that this mode of death is non-apoptotic. These findings demonstrate that anti-HLA DR mAb L243 induces a novel model of cell death in ALL cell lines that is independent of caspase activation and dependent on actin reorganization. This data suggests that this novel mAb induced death pathway is independent of apoptosis and potentially exploitable in the clinic in leukemias resistant to chemotherapy apoptosis induction. Disclosures: No relevant conflicts of interest to declare.

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Deregulated CXCR4-CXCL12 Signaling Impacts on the Pathogenesis of DLBCL

Blood ◽

10.1182/blood-2019-130029 ◽

2019 ◽

Vol 134 (Supplement_1) ◽

pp. 1519-1519

Author(s):

Katrin Pansy ◽

Julia Feichtinger ◽

Barbara Ehall ◽

Barbara Uhl ◽

Hildegard T. Greinix ◽

...

Keyword(s):

Bone Marrow ◽

B Cells ◽

Cell Lines ◽

Cxcr4 Expression ◽

Lymphoma Cell ◽

Cxcl12 Expression ◽

Bone Marrow Biopsies ◽

Cxcr4 Antagonists ◽

Apoptotic Effects

Introduction: The interaction of the chemokine receptor CXCR4 and its ligand CXCL12 appears to be implicated in many important biological processes such as proliferation, survival, migration, and/or invasion. Furthermore, it is important for normal leukocyte trafficking. Deregulation of this axis is frequently observed in several hematologic malignancies. In diffuse large B cell lymphomas (DLBCL), the CXCR4-CXCL12 axis is still largely unexplored and published data are contradictive. Hence, we comprehensively studied the CXCR4-CXCL12-axis in our DLBCL cohort as well as the effects of CXCR4 antagonists on lymphoma cell lines in vitro. Methods: We determined the CXCR4 and CXCL12 expression levels in NGCB- and GCB-DLBCL consisting of primary and transformed follicular lymphomas (n=77 in total), the corresponding bone marrow samples (n=63) and non-neoplastic germinal center-B cells (GC-B, n=5) serving as non-malignant control. To investigate the effects of CXCR4 antagonists in vitro and their function in regulation of important pathways (JNK, ERK1/2 and NF-κB) known to be involved in lymphomagenesis, we treated lymphoma cell lines with three different CXCR4 antagonists, AMD070, AMD3100 and WK1 (a novel nicotinic acid derivative of AMD070 - synthesized by us), followed by functional assays and gene expression profile. Results: CXCR4 was 140-fold higher expressed in DLBCL compared to non-neoplastic GC-B cells. Interestingly, higher CXCR4 expression correlated to a clinically advanced stage, to bone marrow infiltration and worse cancer-specific survival in DLBCL. Further expression analysis by using the corresponding bone marrow biopsies demonstrated that CXCL12 expression correlated to the lymphoma infiltration rate and that CXCR4 expression was reduced in remission under therapy. Moreover, two CXCR4 antagonists - AMD070 and especially WK1 - exerted pro-apoptotic effects on CXCR4 positive lymphoma cells in vitro and induced the expression of certain pro-apoptotic genes in CXCR4 positive cell lines. Remarkably, these effects were more pronounced for the WK1. Finally, WK1 treatment resulted in reduced expression of JNK-, ERK1/2- and NFκB/BCR-target genes. Conclusion: Our data demonstrate that the CXCR4-CXCL12 axis is involved in the pathogenesis of DLBCL. Since CXCR4 antagonists exert pro-apoptotic effects and impact lymphoma relevant pathways, they represent interesting molecules to develop novel therapeutic agents. Disclosures No relevant conflicts of interest to declare.

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CXCR4 Expression and Biological Activity Is Dependent on Oxygen Partial Pressure in Acute Myeloid Leukemia.

Blood ◽

10.1182/blood.v112.11.938.938 ◽

2008 ◽

Vol 112 (11) ◽

pp. 938-938

Author(s):

Michael Fiegl ◽

Ismael J. Samudio ◽

Karen Clise Dwyer ◽

Jared Burks ◽

Herbert Fritsche ◽

...

Keyword(s):

Bone Marrow ◽

Flow Cytometry ◽

Acute Myeloid Leukemia ◽

Cell Lines ◽

Myeloid Leukemia ◽

Leukemic Cell ◽

Cxcr4 Expression ◽

Leukemic Cell Lines ◽

Acute Myeloid

Abstract CXCR4, the receptor for bone marrow stroma derived SDF-1, has recently been studied in normal hematopoiesis and hematologic malignancies. Increased expression of CXCR4 by leukemic blasts has been reported by us and others (Konoplev S. et al, Cancer 2007) to be associated with poor prognosis in acute myeloid leukemia (AML). However, all in-vitro studies are usually carried out under unphysiological, i.e. normoxic (21% O2) conditions. We hypothesized that the pO2 in vitro has major impact on the expression of CXCR4, a key receptor for cell migration and intracellular signalling. Thus, pO2 of bone marrow aspirates was measured using the i-STAT Portable Clinical Analyzer and a hypoxic workstation was used providing constant low oxygen content. Surface and total CXCR4 expression was examined in leukemic cell lines and patient samples by flow cytometry, confocal microscopy and Western blotting (WB). In 19 patients, the median pO2 of the bone marrow was determined as 46.1±12.8 mmHg (6.1±1.7%) with no significant difference between patients with AML (n=7, pO2 41.3±11.2 mmHg) and patients in CR (n=12, pO2 48.3±15.9 mmHg). This level of hypoxia significantly increases surface and total expression of CXCR4 in the leukemic cell lines U937 and OCI-AML3 as well as in samples from patients with AML, as compared to normoxic conditions (~2.8fold increase). This increase happened mainly within the first 2–8 hours of hypoxia and was unrelated to increased CXCR4 transcription, as shown by PCR. Re-oxygenation of leukemic cells resulted in a statistical significant degradation of CXCR4 (~3fold decrease) in all examined cell lines and patient samples (n=10). This loss of CXCR4 is very rapid (within 5 minutes of re-oxygenation) and was detected by flow cytometry, confocal microscopy and WB. This phenomenon was independent of proteasome activity and ATP. Detailed analysis of membraneous lipid rafts by sucrose density separation, cholesterol depletion and flow cytometry analysis for GM1 gangliosides showed structural (distinct re-distribution of Lck in lipid rafts) and quantitative changes (loss of cholesterol and CXCR4) during re-oxygenation. Moreover, part of the loss of CXCR4 can be attributed to sequestration of microparticles into the extracellular environment as shown by WB of supernatant of re-oxygenated cells and by a significant increase (~1.5fold) in the amount of microparticles released by cells (cell lines U937 and OCI-AML3 and additional patient samples) during the process of re-oxygenation, as measured by flow cytometry. In summary, this study determined the oxygen content of CR and leukemic bone marrow samples as 6.1±1.7%. This pO2 is associated with an increase in CXCR4 expression on AML cells, while re-oxygenation leads to a rapid decrease of CXCR4, perhaps in part by shedding of CXCR4- containing microparticles. These studies point to the importance of studying leukemic blasts under physiologic, i.e. hypoxic conditions.

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Identification of CXCR4 Expression By Targeted PET/MR Imaging in Patients with Acute Myeloid Leukemia (AML)

Blood ◽

10.1182/blood.v126.23.1275.1275 ◽

2015 ◽

Vol 126 (23) ◽

pp. 1275-1275

Author(s):

Peter Herhaus ◽

Stefan Habringer ◽

Kathrin Philipp-Abbrederis ◽

Tibor Vag ◽

Carlos Gerngroß ◽

...

Keyword(s):

Flow Cytometry ◽

Mr Imaging ◽

Cell Lines ◽

Chemokine Receptor ◽

Clinical Studies ◽

Surface Expression ◽

Cxcr4 Expression ◽

Whole Body ◽

Myeloid Malignancies ◽

Bm Niche

Abstract Introduction AML is an aggressive hematological neoplasm originating from hematopoietic precursor or stem cells and is rapidly fatal if untreated. Although rates of complete remission (CR) approach 80% in patients with favorable risk profile according to European Leukemia Net classification, CR rates drop dramatically within the intermediate or adverse prognostic groups, and most patients relapse in spite of CR. The origin of refractory or relapsed disease is - according to several studies - the bone marrow (BM) niche that protects the leukemia initiating cells (LIC) from cytotoxic drugs.The chemokine receptor CXCR4 is a key factor mediating the crosstalk between the BM niche and LICs. CXCR4 is a G-protein coupled chemokine receptor with Stromal cell-derived factor-1α (SDF-1α) as its single known chemokine-ligand, and high expression is associated with poor prognosis in AML. Targeting the CXCR4/SDF-1αaxis with small peptide inhibitors or monoclonal antibodies has shown promising results in preclinical and clinical studies, thus rendering it an attractive target for future therapeutic strategies (Peled & Tavor, Theranostics, 2014). In this observational study we analyzed whether the new CXCR4-targeted positron emission tomography (PET)-probe [68Ga]-Pentixafor (Philipp-Abbrederis et al, EMBO Mol Med, 2015; Wester et al, Theranostics, 2015) is applicable for molecular imaging of patients with AML with the goal to develop a CXCR4- targeted peptide-receptor-radiotherapy (PRRT). Methods Using myeloid malignancies (MDS, active AML) as an exemplary CXCR4-expressing cancer entity we imaged 10 patients with the CXCR4 specific PET-probe [68Ga]-Pentixafor by whole body PET/magnetic resonance imaging (PET/MR) after they signed informed consent for this observational assessment. Maximum standardized uptake values (SUVmax) of the involved BM areas were compared to BM from patients without BM malignancy assessed in a different study. CXCR4 surface expression of leukemic BM cells of an unselected cohort of 67 patients with myeloid malignancies was analyzed by flow cytometry. CXCR4 expression in 14 established AML cell lines was measured by flow cytometry and quantitative PCR. Results  Out of 10 patients who were imaged with [68Ga]-Pentixafor-PET/MR, 4 - all of them with the diagnosis of an AML - showed visually positive PET signal of the BM. Those areas correlated well with disease infiltration as determined by MR imaging and the meanSUVmax was significantly higher as compared to visually CXCR4 negative patients (meanSUVmax 8.23 ± 5.23 vs. 2.26 ± 0.47; p=0.036). One of the 10 patients presenting with proven extramedullary relapse showed a CXCR4 positive PET signal within the lesion (SUVmax 5.12), whereas the cytological non-involved BM was PET negative (meanSUVmax 1.82). CXCR4 surface expression in established AML cell lines was variable and ranged from low to high, and correlated with mRNA levels. These data reflect the different expression values we found in the cohort of patients with myeloid malignancies. There was a trend to higher CXCR4 surface expression on blasts when AML patients were compared to MDS patients (median fluorescent intensity CXCR4/isotype 1.73 ± 0.25 vs. 0.96 ± 0.06; p=0.063) that became significant when blast frequency exceeds 30% (≤30% vs. >30% blasts: 1.07 ± 0.11 vs. 2.08 ± 0.38; p=0.006). In this patient cohort we did not observe any correlation between CXCR4 expression and factors such as diagnosis (secondary vs. de novo AML), disease status (refractory or relapse vs. no pretreatment), molecular subtypes or cytogenetic aberrations. Discussion Imaging of CXCR4 by PET/MR with [68Ga]-Pentixafor is feasible in patients with AML. Due to the higher uptake in leukemic BM compared to control BM and its low uptake in other organs (e.g. liver, brain and gut), CXCR4 could serve as an attractive new PRRT-target in selected patients with AML. Such PRRT approaches are of special interest in the setting of allogeneic BM transplantation as conventional myeloablative conditioning regimens - although they are associated with a better relapse free survival - show substantial rates of transplant-related mortality and are therefore not applicable in many AML patients due to their age. In particular, therapeutic targeting of CXCR4 by PRRT provides a unique opportunity of integrating a LIC/niche-directed treatment into the conditioning regimen. Such clinical studies are in development. Disclosures Wester: Scintomics GmbH: Other: General Manager. Keller:Roche: Consultancy, Honoraria; Pfizer: Consultancy.

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In Vitro Evaluation of Chitosan Induced Cytotoxicity against Cancerous Cell lines: MCF-7, Saos-2 and HeLa

Anti-Cancer Agents in Medicinal Chemistry ◽

10.2174/1871520619666190507113949 ◽

2019 ◽

Vol 19 ◽

Author(s):

Zeinab Abedian ◽

Niloofar Jenabian ◽

Ali Akbar Moghadamnia ◽

Ebrahim Zabihi ◽

Roghayeh Pourbagher ◽

...

Keyword(s):

Flow Cytometry ◽

Cell Lines ◽

Anticancer Agents ◽

Fibroblast Cells ◽

Apoptosis Induction ◽

Cytotoxic Effects ◽

Cancerous Cell ◽

Significant Concentration ◽

Mcf 7

Objective/ Background: Cancer is still the most common cause of morbidity in world and new powerful anticancer agents without severe side effects from natural sources is important. Methods: The evaluation of cytotoxicity and apoptosis induction was carried out in MCF-7,HeLa and Saos-2 as cancerous cell lines with different histological origin and human fibroblast served as control normal cell. The cells were treated with different concentrations of chitosan and the cytotoxicity was determined using MTT assay after 24, 48 and 72 h .The mode of death was evaluated by flow cytometry . Results: While both types of chitosan showed significant concentration-dependently cytotoxic effects against the three cancerous cell lines, fibroblast cells showed somehow more compatibility with chitosan. On the other hand, there were no significant differences between LMWC and HMWC cytotoxicity in all cell lines. The flow cytometry results showed the apoptosis pattern of death more in Saos-2 and HeLa while necrosis was more observable with MCF7. Also higher viability with both types of chitosan was seen in fibroblast as normal cells Conclusion: Chitosan shows anticancerous effect against 3 cancerous cell lines, while it is compatible with normal diploid fibroblast cells. Furthermore, it seems that the molecular weight of chitosan does not affect its anticancerous property.

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Micronucleus frequencies in lymphoblastoid cell lines measured with the cytokinesis-block technique and flow cytometry

Mutagenesis ◽

10.1093/mutage/10.5.439 ◽

1995 ◽

Vol 10 (5) ◽

pp. 439-445 ◽

Cited By ~ 8

Author(s):

Anne Slavotinek ◽

E. Miller ◽

G.M. Taylor ◽

M. Nüsse ◽

V. van Heyningen

Keyword(s):

Flow Cytometry ◽

Cell Lines ◽

Lymphoblastoid Cell Lines

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Analyzing Cytotoxic and Apoptogenic Properties ofScutellaria litwinowiiRoot Extract on Cancer Cell Lines

Evidence-based Complementary and Alternative Medicine ◽

10.1093/ecam/nep214 ◽

2011 ◽

Vol 2011 ◽

pp. 1-9 ◽

Cited By ~ 15

Author(s):

Zahra Tayarani-Najaran ◽

Seyed Ahmad Emami ◽

Javad Asili ◽

Alireza Mirzaei ◽

Seyed Hadi Mousavi

Keyword(s):

Flow Cytometry ◽

Cell Lines ◽

Cancer Cell ◽

Methylene Chloride ◽

Apoptotic Cell ◽

Malignant Cell ◽

Cancer Cell Lines ◽

Dependent Manner ◽

Antitumor Effects ◽

Mcf 7

TheScutellariaspecies (Lamiaceae) is used as a source of flavonoids to treat a variety of diseases in traditional medicine. In spite of many reports about the cytotoxic and antitumor effects of some species of this genus, anticancer researches on one of the Iranian speciesS. litwinowiihave not yet been conducted.The cytotoxic properties of total methanol extract ofS. litwinowiiand its fractions were investigated on different cancer cell lines including AGS, HeLa, MCF-7, PC12 and NIH 3T3. Meanwhile, the role of apoptosis in this toxicity was explored. The cells were cultured in DMEM medium and incubated with different concentrations of herb plant extracts. Cell viability was quantitated by MTT assay. Apoptotic cells were determined using propidium iodide staining of DNA fragmentation by flow cytometry (sub-G1 peak).Scutellaria litwinowiiinhibited the growth of malignant cells in a dose-dependent manner. Among solvent fractions ofS. litwinowii, the methylene chloride fraction was found to be more toxic compared to other fractions. The IC50values of this fraction against AGS, HeLa, MCF-7 and PC12 cell lines after 24 h were determined, 121.2 ± 3.1, 40.9 ± 2.5, 115.9 ± 3.5 and 64.5 ± 3.4μg/ml, respectively.Scutellaria litwinowiiinduced a sub-G1 peak in the flow cytometry histogram of treated cells compared to control cells indicating that apoptotic cell death is involved inS. litwinowiitoxicity.Scutellaria litwinowiiexerts cytotoxic and proapototic effects in a variety of malignant cell lines and could be considered as a potential chemotherapeutic agent in cancer treatment.

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