In vitro and in vivo production of vascular endothelial growth factor by chronic lymphocytic leukemia cells

Blood ◽  
2000 ◽  
Vol 96 (9) ◽  
pp. 3181-3187 ◽  
Author(s):  
Haijuan Chen ◽  
Andy T. Treweeke ◽  
Dave C. West ◽  
Kathleen J. Till ◽  
John C. Cawley ◽  
...  
Keyword(s):  
Vascular Endothelial Growth Factor ◽  
Endothelial Cell ◽  
Growth Factor ◽  
Chronic Lymphocytic Leukemia ◽  
Culture Media ◽  
Lymphocytic Leukemia ◽  
Vascular Endothelial ◽  
Endothelial Growth Factor ◽  
Vegf Protein

Abstract Expansion of primary solid tumors and their malignant dissemination are angiogenesis-dependent. Vascular endothelial growth factor (VEGF) is the key factor playing a pivotal role in solid tumor-induced angiogenesis. Recent studies indicate that angiogenesis may also be involved in the pathogenesis of certain hemic malignancies, including B-cell chronic lymphocytic leukemia (B-CLL). Mechanisms underlying angiogenesis in B-CLL and the role of VEGF in this process are incompletely understood. In this study, it was examined whether angiogenically functional VEGF is produced by B-CLL cells. Immunohistochemical staining with antibodies against VEGF and CD34, an endothelial cell marker, demonstrated the presence of VEGF protein and abundant blood vessels in infiltrated lymphoreticular tissues. Low levels of VEGF were detected by ELISA in the culture media of unstimulated cells; this was enhanced up to 7-fold by hypoxic stimulation. SDS-PAGE and Western blot analysis of the concentrated culture media showed 2 isoforms of VEGF protein with molecular weights of 28 and 42 kd, respectively. RNA hybridization showed that these cells expressed VEGF mRNA. Reverse transcription–polymerase chain reaction, combined with nucleotide sequence analysis, revealed that the predominantly expressed isoforms were VEGF121 and VEGF165. Moreover, 3H-thymidine incorporation and an in vivo angiogenic assay demonstrated that the VEGF produced by CLL cells can induce angiogenesis by stimulating endothelial cell proliferation. In conclusion, this study shows that B-CLL cells produce VEGF and demonstrates the angiogenic effects of this growth factor, which may be relevant for the tissue phase of the disease.

In vitro and in vivo production of vascular endothelial growth factor by chronic lymphocytic leukemia cells

Blood ◽  
2000 ◽  
Vol 96 (9) ◽  
pp. 3181-3187 ◽  
Author(s):  
Haijuan Chen ◽  
Andy T. Treweeke ◽  
Dave C. West ◽  
Kathleen J. Till ◽  
John C. Cawley ◽  
...  
Keyword(s):  
Vascular Endothelial Growth Factor ◽  
Endothelial Cell ◽  
Growth Factor ◽  
Chronic Lymphocytic Leukemia ◽  
Culture Media ◽  
Lymphocytic Leukemia ◽  
Vascular Endothelial ◽  
Endothelial Growth Factor ◽  
Vegf Protein

Expansion of primary solid tumors and their malignant dissemination are angiogenesis-dependent. Vascular endothelial growth factor (VEGF) is the key factor playing a pivotal role in solid tumor-induced angiogenesis. Recent studies indicate that angiogenesis may also be involved in the pathogenesis of certain hemic malignancies, including B-cell chronic lymphocytic leukemia (B-CLL). Mechanisms underlying angiogenesis in B-CLL and the role of VEGF in this process are incompletely understood. In this study, it was examined whether angiogenically functional VEGF is produced by B-CLL cells. Immunohistochemical staining with antibodies against VEGF and CD34, an endothelial cell marker, demonstrated the presence of VEGF protein and abundant blood vessels in infiltrated lymphoreticular tissues. Low levels of VEGF were detected by ELISA in the culture media of unstimulated cells; this was enhanced up to 7-fold by hypoxic stimulation. SDS-PAGE and Western blot analysis of the concentrated culture media showed 2 isoforms of VEGF protein with molecular weights of 28 and 42 kd, respectively. RNA hybridization showed that these cells expressed VEGF mRNA. Reverse transcription–polymerase chain reaction, combined with nucleotide sequence analysis, revealed that the predominantly expressed isoforms were VEGF121 and VEGF165. Moreover, 3H-thymidine incorporation and an in vivo angiogenic assay demonstrated that the VEGF produced by CLL cells can induce angiogenesis by stimulating endothelial cell proliferation. In conclusion, this study shows that B-CLL cells produce VEGF and demonstrates the angiogenic effects of this growth factor, which may be relevant for the tissue phase of the disease.

Uncovering Thalidomide Mechanism of Action: Neuropilin 1 Represents the Target of Antiangiogenic and Immunomodulatory Effect in Chronic Lymphocytic Leukemia

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 4608-4608
Author(s):  
Krzysztof Giannopoulos ◽  
Marcin Omiotek ◽  
Kamila Kosior ◽  
Radoslaw Mlak ◽  
Malgorzata Kowal ◽  
...  
Keyword(s):  
Vascular Endothelial Growth Factor ◽  
Growth Factor ◽  
Chronic Lymphocytic Leukemia ◽  
Mechanism Of Action ◽  
Lymphocytic Leukemia ◽  
Vascular Endothelial ◽  
Vegf Expression ◽  
Neuropilin 1 ◽  
Endothelial Growth Factor ◽  
Median Expression

Abstract Abstract 4608 In chronic lymphocytic leukemia (CLL) thalidomide was found to significantly decrease the percentage of regulatory T cells (Tregs) as well the number of CLL cells in vivo. In combination with fludarabine, thalidomide was effective both in refractory/relapse and naïve CLL patients. In our recent clinical trial, we also observed a reduction of vascular endothelial growth factor (VEGF) levels during therapy that were correlated with the reduction of Tregs (r2=0.47, p<0.05). Furthermore, gene expression profiles associated with thalidomide response in CLL revealed several genes involved in angiogenesis (Giannopoulos et al. Leukemia 2009). To further characterize the thalidomide mechanism of action in CLL we assessed expression of neuropilin 1 (NRP1), which is a membrane-bound coreceptor to the tyrosine kinase receptor for both vascular endothelial growth factor (VEGF) and semaphorin (SEMA3A) family members. NRP1 plays versatile roles in angiogenesis, cell survival, migration, and invasion. Recently, NRP1 was also found expressed on plasmacytoid dendritic cells (PDC) as well as on Tregs, two immune cell subpopulations involved in tolerance mechanisms commonly deregulated in tumorigenesis. Our analysis showed NRP1 expression on CLL cells, Tregs and PDC of 38 CLL patients. Using five parameter flow cytometry we found increased expression of NRP1 in CLL when compared to cells derived from healthy volunteers. NRP1 expression was 22.7% on CD5+CD19+ CLL cells vs. 6.2% on CD19+ B cells from controls, p=0.03. Furthermore, we found expression of NRP1 on Tregs as well as PDC with a median expression of NRP1 on Tregs of 42.6 % (range: 10 – 100%). NRP1 was expressed on almost all PDC with a median expression of 100% (range: 98.2 – 100%). In functional studies, we found that NRP1 expression might be regulated by VEGF expression levels. Magnetically separated CLL cells increased expression of NRP1 after cell culture with VEGF. Here, VEGF levels of 0.1 – 0.5ng/ml, which are also observed in primary CLL patient samples, effectively induced expression of NRP1. In accordance, we also observed that VEGF upregulates NRP1 expression on magnetically separated Tregs. However, higher VEGF concentrations inhibited NRP1 expression in CLL cells probably due to a negative feedback loop. In conclusion, we found expression of NRP1 on CLL cells, Tregs as well as PDC in patients with CLL, and we could demonstrate that the expression of NRP1 is regulated by VEGF expression levels. Thus, our previously observed thalidomide-induced reduction of VEGF levels along with a reduced percentage of Tregs in CLL might in part be explained by down-regulation of the NRP1 expression. Disclosures: Stilgenbauer: Hoffmann La Roche: Consultancy, Honoraria, Membership on an entity’s Board of Directors or advisory committees, Travel Grants.

Aggretin, a snake venom–derived endothelial integrin α2β1 agonist, induces angiogenesis via expression of vascular endothelial growth factor

Blood ◽  
2004 ◽  
Vol 103 (6) ◽  
pp. 2105-2113 ◽  
Author(s):  
Ching-Hu Chung ◽  
Wen-Bin Wu ◽  
Tur-Fu Huang
Keyword(s):  
Vascular Endothelial Growth Factor ◽  
Endothelial Cell ◽  
Growth Factor ◽  
Umbilical Vein ◽  
Endothelial Cell Proliferation ◽  
Vascular Endothelial ◽  
Angiogenic Effect ◽  
Endothelial Growth Factor

Abstract Aggretin, a collagen-like α2β1 agonist purified from Calloselasma rhodostoma venom, was shown to increase human umbilical vein endothelial cell (HUVEC) proliferation and HUVEC migration toward immobilized aggretin was also increased. These effects were blocked by A2-IIE10, an antibody raised against integrin α2. Aggretin bound to HUVECs in a dose-dependent and saturable manner, which was specifically inhibited by A2-IIE10, as examined by flow cytometry. Aggretin elicited significant angiogenic effects in both in vivo and in vitro angiogenesis assays, and incubation of HUVECs with aggretin activated phosphatidylinositol 3-kinase (PI3K), Akt, and extracellular-regulated kinase 1/2 (ERK1/2); these effects were blocked by A2-IIE10 or vascular endothelial growth factor (VEGF) monoclonal antibody (mAb). The angiogenic effect induced by aggretin may be via the production of VEGF because the VEGF level was elevated and VEGF mAb pretreatment inhibited Akt/ERK1/2 activation as well as the in vivo angiogenesis induced by aggretin. The VEGF production induced by aggretin can be blocked by A2-IIE10 mAb pretreatment. In conclusion, aggretin induces endothelial cell proliferation, migration, and angiogenesis by interacting with integrin α2β1, leading to activation of PI3K, Akt, and ERK1/2 pathways, and the increased expression of VEGF may be responsible for its angiogenic activity.

Clinical relevance of intracellular vascular endothelial growth factor levels in B-cell chronic lymphocytic leukemia

Blood ◽  
2000 ◽  
Vol 96 (2) ◽  
pp. 768-770 ◽  
Author(s):  
Alvaro Aguayo ◽  
Susan O'Brien ◽  
Michael Keating ◽  
Taghi Manshouri ◽  
Cristi Gidel ◽  
...  
Keyword(s):  
Vascular Endothelial Growth Factor ◽  
Growth Factor ◽  
Chronic Lymphocytic Leukemia ◽  
B Cell ◽  
Lymphocytic Leukemia ◽  
Vascular Endothelial ◽  
Early Stage Disease ◽  
Normal Peripheral Blood ◽  
Endothelial Growth Factor ◽  
Cell Chronic Lymphocytic Leukemia

Abstract Strong evidence exists for an association between high vascular endothelial growth factor (VEGF) levels and poor prognoses in patients with solid tumors and acute leukemia. Using Western blot analysis and solid-phase radioimmunoassay, we measured cellular VEGF levels in B-cell chronic lymphocytic leukemia (CLL) samples from 225 patients and correlated these levels with disease characteristics and prognoses. The median VEGF level in CLL samples was 7.26 times the median level detected in normal peripheral blood mononuclear cells. Patients with lower levels of VEGF protein showed a trend toward shorter survival (P = .07). However, in a subgroup of CLL patients with good prognoses or early-stage disease (Rai stages 0-II, Binet stages A,B; β2-M ≤ 2.8 mg/dL), lower levels of VEGF were associated with shorter survival times. For the entire group of patients, no correlation was found between VEGF levels and β2-M levels or Rai and Binet stage. Most samples from patients with CLL expressed the 43-kd VEGF isoform in addition to the commonly expressed 45-kd isoform. It remains to be seen whether the expression of the 43-kd isoform is responsible for this reversed correlation with outcome.

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