The fate of antibodies and their radiolabels bound to tumor cells in vitro: the effect of cross-linking at the cell surface and of anti-idiotype antibodies

1994 ◽  
Vol 39 (5) ◽  
pp. 325-331
Author(s):  
Gaik Lin Ong ◽  
Vikas Marria ◽  
M. Jules Mattes
Keyword(s):  
Cell Surface ◽  
Tumor Cells ◽  
Cross Linking

scholarly journals Induction of Apoptosis of Metastatic Mammary Carcinoma Cells In Vivo by Disruption of Tumor Cell Surface CD44 Function

1997 ◽  
Vol 186 (12) ◽  
pp. 1985-1996 ◽  
Author(s):  
Qin Yu ◽  
Bryan P. Toole ◽  
Ivan Stamenkovic
Keyword(s):  
Cell Surface ◽  
Tumor Cell ◽  
Tumor Cells ◽  
Lung Tissue ◽  
Mammary Carcinoma ◽  
Cell Types ◽  
Pulmonary Endothelium ◽  
Soluble Cd44

To understand how the hyaluronan receptor CD44 regulates tumor metastasis, the murine mammary carcinoma TA3/St, which constitutively expresses cell surface CD44, was transfected with cDNAs encoding soluble isoforms of CD44 and the transfectants (TA3sCD44) were compared with parental cells (transfected with expression vector only) for growth in vivo and in vitro. Local release of soluble CD44 by the transfectants inhibited the ability of endogenous cell surface CD44 to bind and internalize hyaluronan and to mediate TA3 cell invasion of hyaluronan-producing cell monolayers. Mice intravenously injected with parental TA3/St cells developed massive pulmonary metastases within 21–28 d, whereas animals injected with TA3sCD44 cells developed few or no tumors. Tracing of labeled parental and transfectant tumor cells revealed that both cell types initially adhered to pulmonary endothelium and penetrated the interstitial stroma. However, although parental cells were dividing and forming clusters within lung tissue 48 h following injection, >80% of TA3sCD44 cells underwent apoptosis. Although sCD44 transfectants displayed a marked reduction in their ability to internalize and degrade hyaluronan, they elicited abundant local hyaluronan production within invaded lung tissue, comparable to that induced by parental cells. These observations provide direct evidence that cell surface CD44 function promotes tumor cell survival in invaded tissue and that its suppression can induce apoptosis of the invading tumor cells, possibly as a result of impairing their ability to penetrate the host tissue hyaluronan barrier.

scholarly journals Tissue Transglutaminase Is an Integrin-Binding Adhesion Coreceptor for Fibronectin

2000 ◽  
Vol 148 (4) ◽  
pp. 825-838 ◽  
Author(s):  
Sergey S. Akimov ◽  
Dmitry Krylov ◽  
Laurie F. Fleischman ◽  
Alexey M. Belkin
Keyword(s):  
Cell Surface ◽  
Focal Adhesion ◽  
Factor Xiii ◽  
Tissue Transglutaminase ◽  
Focal Adhesions ◽  
Cross Linking ◽  
Binding Motifs ◽  
High Affinity ◽  
Β2 Integrins

The protein cross-linking enzyme tissue transglutaminase binds in vitro with high affinity to fibronectin via its 42-kD gelatin-binding domain. Here we report that cell surface transglutaminase mediates adhesion and spreading of cells on the 42-kD fibronectin fragment, which lacks integrin-binding motifs. Overexpression of tissue transglutaminase increases its amount on the cell surface, enhances adhesion and spreading on fibronectin and its 42-kD fragment, enlarges focal adhesions, and amplifies adhesion-dependent phosphorylation of focal adhesion kinase. These effects are specific for tissue transglutaminase and are not shared by its functional homologue, a catalytic subunit of factor XIII. Adhesive function of tissue transglutaminase does not require its cross-linking activity but depends on its stable noncovalent association with integrins. Transglutaminase interacts directly with multiple integrins of β1 and β3 subfamilies, but not with β2 integrins. Complexes of transglutaminase with integrins are formed inside the cell during biosynthesis and accumulate on the surface and in focal adhesions. Together our results demonstrate that tissue transglutaminase mediates the interaction of integrins with fibronectin, thereby acting as an integrin-associated coreceptor to promote cell adhesion and spreading.

scholarly journals Acquisition of cell surface IgD after in vitro culture of neoplastic B cells from the murine tumor BCL1.

1980 ◽  
Vol 151 (3) ◽  
pp. 749-754 ◽  
Author(s):  
P C Isakson ◽  
J W Uhr ◽  
K A Krolick ◽  
F Finkelman ◽  
E S Vitetta
Keyword(s):  
B Cells ◽  
Cell Surface ◽  
In Vitro Culture ◽  
Cell Line ◽  
Tumor Cells ◽  
Murine Tumor ◽  
Monoclonal Cell Line

Murine BCL1 tumor cells bear large amounts of surface IgM and trace amounts of surface IgD. In the present studies we have shown that cultivation of these cells, in the absence of lipopolysaccharide, results in the acquisition of IgD by virtually all the cells. These results suggest that BCL1 cells can differentiate in vitro into more mature B cells and offer an attractive model for analyzing the factors controlling appearance of IgD on a monoclonal cell line.

scholarly journals Inhibition of cell growth by monoclonal anti-transferrin receptor antibodies.

1985 ◽  
Vol 5 (8) ◽  
pp. 1814-1821 ◽  
Author(s):  
J F Lesley ◽  
R J Schulte
Keyword(s):  
Cell Growth ◽  
Cell Surface ◽  
Transferrin Receptor ◽  
Immunoglobulin M ◽  
Cross Linking ◽  
Igg Antibody ◽  
Igm Antibodies ◽  
Igm Antibody ◽  
Mutant Cells

Five anti-murine transferrin receptor monoclonal antibodies have been characterized with respect to immunoglobulin class, effects on binding of transferrin, and effects on AKR1 lymphoma cell growth in vitro. The immunoglobulin M (IgM) antibodies, but not the IgG antibodies, prevent cell growth. We suggest that the profound effects of the IgM antibodies on cell growth are probably due to extensive cross-linking of cell surface receptors. In support of this, we are able to mimic the growth-inhibiting effects of the IgM antibodies by adding antiimmunoglobulin to an IgG antibody. By flow microfluorimetry, we show that an IgG antibody by itself induces up to a 10-fold downward regulation in the cell surface transferrin receptor, which is accompanied by accelerated receptor degradation. A similar downward regulation is seen in mutant cells resistant to growth inhibition by an IgM antibody, when grown in the selecting antibody. Wild-type cells grown in the presence of IgM antibody do not show receptor downward regulation. Inhibitory effects of antibody plus antiimmuoglobulin on mutant cells are also consistent with extensive cross-linking causing inhibition of growth.

scholarly journals Pre-Clinical Combination of AO-176, a Highly Differentiated Clinical Stage CD47 Antibody, with Either Azacitidine or Venetoclax Significantly Enhances DAMP Induction and Phagocytosis of Acute Myeloid Leukemia

Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 9-10
Author(s):  
Mike J Donio ◽  
W. Casey Wilson ◽  
Isra Darwech ◽  
Gabriela Andrejeva ◽  
Benjamin J Capoccia ◽  
...  
Keyword(s):  
Acute Myeloid Leukemia ◽  
Cell Surface ◽  
Tumor Cell ◽  
Tumor Cells ◽  
Cell Lines ◽  
Myeloid Leukemia ◽  
Innate Immune ◽  
Private Company ◽  
Acute Myeloid

While T cell checkpoint inhibitors are mainstays of cancer immunotherapy, therapies that direct innate immune responses against cancer are lacking. CD47, a "don't eat me" signal, is an innate immune cell checkpoint which binds SIRPα on macrophages and dendritic cells to limit phagocytosis and its upregulation on tumor cells leads to evasion of immune detection and clearance. Therapeutic antibodies have previously been developed to block CD47 and induce phagocytosis of tumor cells, thus validating the pathway. AO-176, a next generation humanized IgG2 anti-CD47 antibody, was developed to block the CD47/SIRPα interaction and induce tumor cell phagocytosis. Moreover, AO-176 directly kills tumor cells through a non-ADCC-dependent mechanism via induction of programmed cell death type III. In addition to these tumor eliminating properties, AO-176 has the potential for a strong safety profile as a result of its preferential binding to tumor versus normal cells, lack of RBC binding, and enhanced binding to tumor cells at acidic pH. CD47 has previously been shown to be upregulated on acute myeloid leukemia (AML) leukemic stem cells (LSC), enabling their expansion through evasion from phagocytic clearance. As a result, patients with increased CD47 on AML LSCs have worse overall survival. In this study, AO-176 efficacy was evaluated in AML cell lines as a single agent and in combination with azacitidine and venetoclax which are approved therapies for AML. Azacitidine is a cytosine analogue which acts to inhibit DNA methylation, and venetoclax is a potent Bcl-2 inhibitor. Previous studies have shown that azacitidine induces apoptosis of tumor cells and increases cell surface exposure of calreticulin, a DAMP (Damage Associate Molecular Pattern) which provides a strong pro-phagocytic signal. From these findings, it was hypothesized that azacitidine would enable increased tumor cell phagocytosis when combined with AO-176. The potential for a similar enhancement with a combination of AO-176 and venetoclax was also explored. The ability of AO-176, with or without azacitidine or venetoclax, to induce DAMPs on the surface of AML cells was assessed. Cell surface expression of DAMPs, calreticulin and PDIA3, were measured by flow cytometry. AO-176, azacitidine, and venetoclax as single agents potently increased both calreticulin and PDIA3 in a dose-dependent manner on AML cell lines such as HL60 This is the first time, to our knowledge, that venetoclax has been shown to induce DAMPs. To better understand the functional implications of these findings, in vitro phagocytosis assays were performed. Azacitidine and venetoclax significantly enhanced AO-176-mediated phagocytosis of AML cells compared to any of the agents alone. Moreover, when AO-176 was combined with azacitidine in direct tumor cell killing assays, enhanced activity was observed in a subset of AML cell lines. In conclusion, AO-176 combined with either azacitidine or venetoclax, resulted in significant enhancement of phagocytic AML cell clearance in vitro which also correlated with the ability of these agents to induce DAMPs. In vivo treatment with AO-176 in combination with these agents is in progress. AO-176 is being evaluated in phase 1 clinical trials for the treatment of patients with solid tumors (NCT03834948) and multiple myeloma (NCT04445701). Disclosures Donio: Arch Oncology: Current Employment, Current equity holder in private company. Wilson:Arch Oncology: Current Employment, Current equity holder in private company. Darwech:Arch Oncology: Current Employment, Current equity holder in private company. Andrejeva:Arch Oncology: Current Employment, Current equity holder in private company. Capoccia:Arch Oncology: Current Employment, Current equity holder in private company. Puro:Arch Oncology: Current Employment, Current equity holder in private company. Kashyap:Arch Oncology: Current Employment, Current equity holder in private company. Pereira:Arch Oncology: Current Employment, Current equity holder in private company.

Clinical significance of circulating tumor cells identified by cell-surface vimentin in pancreatic cancer.

2019 ◽  
Vol 37 (15_suppl) ◽  
pp. e14562-e14562
Author(s):  
Tao Wei ◽  
Qi Zhang ◽  
Tingbo Liang ◽  
Xueli Bai
Keyword(s):  
Pancreatic Cancer ◽  
Cell Surface ◽  
Tumor Cells ◽  
Circulating Tumor Cells ◽  
Clinical Significance ◽  
Ductal Adenocarcinoma ◽  
Rank Test ◽  
Epithelial Tumor ◽  
Mesenchymal Phenotype

e14562 Background: Identification of circulating tumor cells (CTCs) largely rely on epithelial tumor cell marker. Here we sought to interrogate whether cell-surface vimentin could be a biomarker for isolating CTCs potentially with mesenchymal phenotype in pancreatic ductal adenocarcinoma (PDAC). Methods: In total, 100 PDAC patients, 16 patients with intraductal papillary mucinous neoplasm (IPMN), and 30 healthy individuals were enrolled between December 2016 and November 2017. Potential CTCs were captured in 4 ml blood samples by vimentin antibody-coated microfluidic chip. CTCs were defined as vimentin+CD45-Hoechst+. Results: In vitro experiment showed that vimentin was highly expressed on the surface of pancreatic tumor cells with mesenchymal phenotype. Overall, vimentin+ CTCs were detected in 76% of patients with PDAC, but only in 2 out 30 healthy donors. Besides, five patients (31.3%) with IPMN had vimentin+ CTCs, and 10 CTCs were identified in one case. Using a cut-off value of two cells/4 ml of blood, 65% PDAC patients were positive for vimentin+ CTCs , while the positivity rates for the patients with IPMN and the healthy controls were 25% and 0%, respectively. Combined vimentin+ CTCs and CA19-9 offered a favorable diagnostic potency with area under curve of 0.968. Vimentin+ CTCs counts correlated with change of tumor burden for patients undergoing resection ( P < 0.01). Significant reduction of CTCs counts was observed after chemotherapy for subjects responding to treatment ( P < 0.05). The paired analysis showed that CTC counts was higher in portal vein blood than peripheral blood for 10 patients with available samples ( P < 0.05). Patients with 2 or more CTCs detected had more advanced disease and poorer differentiated tumor. In addition, preoperative higher CTCs counts correlated with shortened recurrence-free survival (Log-rank test: P = 0.02). Conclusions: Vimentin+ CTCs serves as a reliable biomarker in pancreatic cancer. The enrichment of potential mesenchymal CTCs could complement the strategy capturing epithelial CTCs, and provides a way to more thoroughly interrogate the biology and clinical significance of CTCs in PDAC.

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