The SMAC Mimetic Lcl-161 Augments the in Vitro and in Vivo anti-Tumor Activity of Rituximab and Chemotherapy in Rituximab Relapse/Refractory Lymphoma Models

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 3110-3110 ◽  
Author(s):  
Kyle L. Runckel ◽  
Joseph Skitzki ◽  
Francisco Hernandez ◽  
Myron S. Czuczman

Abstract The addition of rituximab to front-line therapy regimens in diffuse large B-cell lymphoma (DLBCL) has greatly improved clinical outcomes, but is also associated with a disease that is more resistant to salvage chemotherapy in the second-line setting, reinforcing the need for new therapies targeted at the overlapping resistance pathways between rituximab and chemotherapy. To better understand the mechanisms responsible for rituximab/chemotherapy cross-resistance we developed several rituximab resistance cell lines which exhibited significant concurrent chemotherapy resistance. These multi-therapy resistant cell lines (TRCL) exhibit decreased expression of the pro-apoptotic Bcl-2 family proteins Bak and Bak, along with over-expression of several anti-apoptotic proteins, including the inhibitor of apoptosis proteins (IAP) survivin and livin (determined by Western blot). High IAP expression has been associated with inferior clinical outcomes in a range of hematological malignancies, and solid tumors. To determine the impact of IAP over-expression on TRCL rituximab/chemotherapy resistance we utilized a transient siRNA knockdown of both survivn and livin. TRCLs with livin knockdown had a statistically significant improvement in response to several chemotherapy agents including doxorubicin, vincristine, and the proteasome inhibitor carfilzomib (measured at 48 hours with the Cell Titer-Glo viability assay). These results support livin over-expression as a key lymphoma therapy resistance mechanism, and establish IAPs as potential therapeutic targets. Small molecule IAP inhibitors, like LCL-161 (obtained from Novartis), are chemical mimetics of the endogenous IAP antagonist termed the second mitochondrial inhibitor of caspases (SMAC). Western blot analysis indicated that TRCLs treated in vitro with LCL-161 exhibited a dose dependent decrease in the expression of several IAPs, including livin. In addition, LCL-161 increased rates of TRCL apoptosis, and produced synergistic anti-tumor activity when combined with cytarabine, gemcitabine, and carfilzomib in vitro. LCL-161 also enhanced the ex vivo anti-tumor activity of carfilzomib against primary tumor cells isolated from lymphoma patients with both de novo, and relapse/refractory disease. Cell viability and apoptosis induction were determined at 48 hours with CellTiter-Glo viability assays and flow cytometry respectively. To evaluate the anti-tumor effect of LCL-161 in vivo severe combined immunodeficiency (SCID) mice were inoculated with the TRCL Raji-4RH via tail vein injection (iv), and assigned to observation or treatment arms 7 days after inoculation. Treatments were LCL-161 alone (60mg/kg), the combination of rituximab: 10mg/kg, gemcitabine: 120mg/kg, and vinorelbine: 8mg/kg (RGV), or LCL-161 and RGV together. LCL-161 was administered on day 7 as one dose given p.o. by gavage; RGV was also administered on day 7 as a single i.v. dose given by tail vein injection. Differences in survival (measured as the time to the development of limb paralysis) were evaluated with the Log-rank, Breslow, and Tarone-Ware tests across treatment arms. As a single agent LCL-161 was ineffective in controlling Raji-4RH tumor growth in vivo. However, the combination of LCL-161 with RGV (median survival 133 days) resulted in a statistically significant (P=0.002 with each test) improvement in overall survival when compared to RGV alone (median survival 53 days). In summary, IAPs, especially livin, contribute to rituximab/chemotherapy resistance in relapse/refractory B-cell lymphoma models. However, the IAP inhibitor LCL-161 can disrupt this resistance and augment the effect of chemotherapy in resistant lymphoma cell line models, as well as relapse/refractory lymphoma patient samples. In addition, LCL-161 can improve the anti-tumor activity of the RGV chemotherapy regimen, and increase overall survival in a mouse in vivo model of human rituximab/chemotherapy resistant lymphoma. Our data supports the continued investigation of LCL-161 as a novel and effective targeted agent for the treatment of aggressive rituximab relapse/refractory B-cell lymphomas. (Supported by a NHI SPORE Lymphoma grant: 5 P50 CA130805-04, a NIH grant R01 CA136907-01A1 and The Eugene and Connie Corasanti Lymphoma Research Fund) Disclosures No relevant conflicts of interest to declare.

Cancers ◽  
2021 ◽  
Vol 13 (17) ◽  
pp. 4249
Author(s):  
Xing Wang ◽  
Dedao Wang ◽  
Ning Ding ◽  
Lan Mi ◽  
Hui Yu ◽  
...  

Background: Upregulation of H3K27me3 induced by EZH2 overexpression or somatic heterozygous mutations were implicated in lymphomagenesis. It has been demonstrated that several EZH2-target agents have notable therapeutic effects in EZH2-mutant B-cell lymphoma patients. Here we present a novel highly selective EZH2 inhibitor SHR2554 and possible combination strategy in diffuse large B-cell lymphoma (DLBCL). Methods: Cell proliferation, cell cycle and apoptosis were analyzed by CellTiter-Glo Luminescent Cell Viability Assay and flow cytometry. Western Blot was used to detect the expression of related proteins. The gene expression profiling post combination treatment was analyzed by RNA-Seq. Finally, CDX and PDX models were used to evaluate the synergistic anti-tumor effects of the combination treatment in vivo. Results: The novel EZH2 inhibitor SHR2554 inhibited proliferation and induced G1 phase arrest in EZH2-mutant DLBCL cell lines. The combination of EZH2 inhibitor SHR2554 with histone deacetylase (HDAC) inhibitor chidamide (hereafter referred to as HBI8000) exerted synergistic anti-proliferative activity in vitro and in vivo. Gene expression profile analysis revealed dramatic inhibition of the DNA replication process in combined treatment. Conclusions: SHR2554, a potent, highly selective small molecule inhibitor of EZH2, inhibited EZH2-mutant DLBCL more significantly in vitro and in vivo. The combination of HDAC inhibitor HBI8000 with EZH2 inhibitor SHR2554 exhibited dramatic anti-tumor activity in both mutant and wild-type DLBCL, which may become a potential therapeutic modality for the treatment of DLBCL patients.


Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 3941-3941
Author(s):  
David M Goldenberg ◽  
Serengulam Govindan ◽  
Tom M Cardillo ◽  
Robert M Sharkey

Abstract Abstract 3941 Background: Monoclonal antibody (MAb) therapy has had a significant impact on the management of B-cell malignancies, but is most often used in combination with chemotherapy. We developed an ADC that combines SN-38, the active component of irinotecan, a topoisomerase I inhibitor, with the internalizing, humanized, anti-CD22 IgG, epratuzumab, and determined its activity alone and in combination with an anti-CD20 antibody therapy (veltuzumab). Methods: Epratuzumab was conjugated with SN-38 (E-SN-38) at a mole ratio of ∼6:1. The conjugate is designed specifically to be released slowly in the presence of serum (50% released over ∼1.5 days), allowing liberation of the drug when internalized, but also being released locally after being bound to the tumor. In vitro and in vivo studies were performed to assess the activity of the conjugate against several subcutaneously- or intravenously-inoculated B-cell lymphoma cell lines. In vivo studies also examined combination therapy using E-SN-38 and the veltuzumab (V). Results: In vitro studies in 4 B-cell lymphoma cells lines (Daudi, Raji, Ramos, WSU-FSCCL) and 4 acute lymphoblastic lymphoma cell lines (697, REH, MN-60, and RS4;11) expressing varying amounts of CD22 showed an IC50 for E-SN-38 in the nanomolar range, confirming potent activity. Nude mice bearing SC Ramos human lymphoma had significant selective anti-tumor activity compared to a control, non-targeting, IgG-SN-38 conjugate, at a dosing regimen of 75 to 250 μg of the conjugates given twice-weekly for 4 weeks. Significant anti-tumor activity was also found in several other cell lines. When combined with veltuzumab, significant improvement in therapeutic activity was observed. For example, median survival in a WSU-FSCCL human follicular B-cell lymphoma IV model with treatment initiated 5 days after implantation was 42 d (0/10 surviving at 160 d) and 91 d (2/10 surviving) for untreated and veltuzumab-treated animals, respectively; 63d (0/10 surviving after 160 d) and >160 d (with 6/10 surviving) for E-SN-38 and E-SN-38 + V, respectively; and 63 d (0/10) and 91 d (2/10) for non-targeting IgG-SN-38 conjugate alone and combined with V). The E-SN-38 conjugate combined with V was significantly better than all treatment or control groups (P ≤ 0.05). Conclusion: E-SN-38 ADC is a potent therapeutic, even at non-toxic dose levels, and shows significantly enhanced efficacy when combined with anti-CD20 immunotherapy, representing an important new ADC treatment regimen. Disclosures: Goldenberg: Immunomedics, Inc.: Membership on an entity's Board of Directors or advisory committees, Patents & Royalties. Govindan:Immunomedics, Inc.: Employment. Cardillo:Immunomedics, Inc.: Employment.


Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 3970-3970
Author(s):  
Na Yang ◽  
Wei Deng ◽  
Qiaoling Sun ◽  
Junqing Liang ◽  
Linfang Wang ◽  
...  

Abstract Introduction: Spleen Tyrosine Kinase (SYK), a non-receptor type of tyrosine kinase, is a member of Syk/ZAP70 tyrosine kinase family. It plays a pivotal role in the regulation of B-cell receptor (BCR) signal pathway, which regulates proliferation, differentiation and survival of B lymphocytes. The abnormal activation of BCR singling is closely related to transformation and development of B cell lymphoma. Targeting BCR downstream molecules, such as Bruton' tyrosine kinase (BTK) and phosphoinositide-3-kinase δ (PI3Kδ) has emerged as new therapeutic approaches and inhibitors of BTK and PI3Kδ were approved recently by FDA for treatment of some subtypes of B-cell malignancies. Currently, a couple small molecular inhibitors against SYK, another BCR downstream molecule, are under the early clinical development and showed initial efficacy in B cell lymphomas. HMPL-523, discovered and currently being developed in Phase I clinical trial by Hutchison MediPharma, is a novel, highly potent and selective SYK inhibitor (IC50: 0.025 μM). The anti-tumor activity of HMPL-523 was evaluated in this study. Methods: Inhibitory effects of HMPL-523 on cell viability were investigated in a panel of B cell lymphoma cell lines with SYK/BCR dysregulation by CellTiter-Glo luminescent or CCK-8 assay. The effect of HMPL-523 on SYK signaling pathway was detected by western blot. Annexin-V- positive and PI-negative population was recognized as apoptotic cells by FACS. Nude mice bearing B cell lymphoma xenograft tumors with SYK/BCR dysregulation were used to determine anti-tumor activity of HMPL-523 in vivo. Result: HMPL-523 blocked phosphorylation of BLNK, downstream protein of Syk, in human mantle cell line REC-1 and human plasma cell line ARH-7777 with IC50 of 0.105 µM and 0.173 μM, respectively. HMPL-523 also inhibited cell viability of Ba/F3 Tel-Syk with IC50 of 0.033 μM. Furthermore, inhibitory effects of HMPL-523 on cell viability were evaluated in a panel of B -cell lymphoma cell lines with SYK/BCR deregulation. Results showed that HMPL- 523 potently inhibited cell survival with IC50s from 0.4 to 2 μM. Consistent with the effect on cell viability, HMPL-523 increased the apoptotic rate of REC-1 cells. Moreover, HMPL-523 showed the synergistic activities on killing human diffused large B cell lymphoma (DLBCL) in combination with other drugs such as BTK inhibitor, PI3Kδ inhibitors and Bcl2 family inhibitor. The detailed mechanisms underlying the synergism are still under investigation. Anti-tumor activity of HMPL-523 was determined in Syk dependent xenograft models. Daily oral administration of 100 mg/kg HMPL-523 showed potent anti-tumor activity in B cell lymphoma REC-1 (TGI: 59%). Conclusion:HMPL-523 is a highly potent SYK inhibitor with good activity against B-cell lymphoma in pre-clinical in vitro and in vivo models, supporting further clinical research for HMPL-523 as either single agent or combination drug with other agents to treat B-cell malignancies e.g. DLBCL Disclosures Yang: Hutchison MediPharma Ltd: Employment, Research Funding. Deng:Hutchison MediPharma Ltd: Employment, Research Funding. Sun:Hutchison MediPharma Ltd: Employment, Research Funding. Liang:Hutchison MediPharma Ltd: Employment, Research Funding. Wang:Hutchison MediPharma Ltd: Employment, Research Funding. Fan:Hutchison MediPharma Ltd: Employment, Research Funding. Tang:Hutchison MediPharma Ltd: Employment, Research Funding. Yu:Hutchison MediPharma Ltd: Employment, Research Funding. Sun:Hutchison MediPharma Ltd: Employment, Equity Ownership. Zhou:Hutchison MediPharma Ltd: Employment, Research Funding. Dai:Hutchison MediPharma Ltd: Employment, Research Funding. Qing:Hutchison MediPharma Ltd: Employment, Research Funding. Su:Hutchison MediPharma Ltd: Employment, Research Funding. Ren:Hutchison MediPharma Ltd: Employment, Research Funding.


Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 2490-2490 ◽  
Author(s):  
John F. DiJoseph ◽  
Douglas C. Armellino ◽  
Maureen M. Dougher ◽  
Arthur Kunz ◽  
Erwin R. Boghaert ◽  
...  

Abstract Antibody-targeted chemotherapy using tumor-targeted immunoconjugates of the cytotoxic agent, calicheamicin, is a clinically validated strategy for the treatment of acute myeloid leukemia. Calicheamicin is a potent cytotoxic natural product that binds DNA in the minor groove and causes double strand DNA breaks. B lymphoid lineage-specific antigens CD19, CD20, and CD22 have been studied extensively as potential targets for therapeutic applications of immunotoxins. In order to determine which one of these three antigens is most suitable for antibody-targeted calicheamicin therapy, we conjugated monoclonal antibodies, BU12 (murine anti-CD19 mAb), rituximab (chimeric anti-CD20 mAb), and m5/44 (murine anti-CD22 mAb) to a hindered disulfide derivative of N-acetyl gamma calicheamicin and evaluated the anti-tumor activity of these conjugates against three human B-cell lymphoma lines (BCL), Ramos, Raji and RL. Each of these three mAb bound to their respective antigens on the surface of BCL and was modulated, indicative of their potential internalization. Immunoconjugates of these mAbs, prepared by covalently linking calicheamicin via either acid-labile or acid-resistant linkers, caused a potent inhibition of BCL growth in vitro (IC50s ranged from 7 pM for the acid-labile linked m544 up to 6.8 nM for the acid-resistant linked anti-CD20 conjugates of calicheamicin). Immunoconjugates with acid-labile linkers were more potent than their counterparts with the acid-stable linker and conjugates targeted to either CD19 or CD22 were more potent than those targeted to CD20 in inhibiting BCL growth in vitro. In contrast, unconjugated mAb to CD19 or CD22 had no effect on BCL growth in vitro whereas anti-CD20 mAb, at concentrations >1 μg/ml, had an inhibitory effect of 30% on in vitro BCL growth. When examined for their effects on the growth of established subcutaneous BCL xenografts in nude mice, calicheamicin conjugated to anti-CD22 was by far the most efficacious conjugate against each of the three BCL xenografts studied. Calicheamicin conjugated to rituximab caused significant inhibition of BCL growth but was less effective than the conjugates of anti-CD22 or anti-CD19 mAb. Interestingly, anti-CD19 conjugates of calicheamicin, while effective in vitro against both Raji and Ramos BCL and effective against Raji BCL xenografts, had no effect on the growth of Ramos BCL xenografts in vivo. The reasons underlying the lack of anti-tumor activity of CD19-targeted calicheamicin conjugate against Ramos xenografts in vivo remain unknown. Based on a number of factors including the potent and consistent anti-tumor activity of the anti-CD22-conjugated calicheamicin, CD22 was selected as the molecular target for further development. A calicheamicin conjugate containing an acid-labile linker of humanized anti-CD22 mAb, CMC-544, is currently being evaluated in phase I clinical trials in non-Hodgkin’s B-cell lymphoma.


Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 2353-2353
Author(s):  
Nishitha Reddy ◽  
Francisco J. Hernandez-Ilizaliturri ◽  
Joy Knight ◽  
Czuczman S. Myron ◽  

Abstract Lenalidomide, a thalidomide analog, has dual anti-tumor activities against B-cell lymphomas and other hematological malignancies by inducing direct apoptosis in malignant cells and modulating the tumor microenviroment (angiogenesis inhibition) or the host immune response. We previously demonstrated that lenalidomide enhances rituximab-mediated antibody dependent cellular cytotoxicity (ADCC). In our current work we further studied the effects of combining lenalidomide with galiximab (IDEC114), a primatized anti-CD80 monoclonal antibody, which is undergoing clinical testing in B-cell lymphoma. To this end a panel of rituximab-sensitive or rituximab-resistant B-cell lymphoma cell lines was exposed in vitro to lenalidomide (10μg/ml) or DMSO (0.01%) with our without galiximab (10μg/ml) or isotype control antibody (10μg/ml) and incubated at 37°C, 5%CO2 over five days. Changes in DNA synthesis were determined by measuring [3H]-thymidine uptake at 24 and 48 hrs. To asses changes in galiximab-mediated ADCC, peripheral blood mononuclear cells (PBMCs) isolated from healthy volunteers were incubated with lenalidomide or control for 72 hrs. Subsequently, NHL cells were labeled with 51Cr and then exposed to galiximab or isotype control (10mg/ml) and PBMCs (Effector:Target ratio, 40:1). For in vivo studies, 6–8 week old SCID mice were inoculated with 1×106 Raji cells via tail vein injection and after a period of 72 hours, in order to allow for tumor engraftment, animals were divided into four cohorts (control, lenalidomide alone, galiximab alone, and lenalidomide + galiximab). Lenalidomide was administered intraperitoneally (i.p) at 0.5mg/kg/dose on days +3, +4, +8, +9, +13, +14, +18 and +19. Galiximab was administered via tail vein injection at 10mg/kg/dose on days +5, +10, +15 and +20. Difference in survival between treatment groups was performed by Kaplan-Meier analysis. Results: In vitro exposure of various NHL cells to lenalidomide for five consecutive days enhanced the anti-proliferative effects of galiximab against Raji cells (40% of growth inhibition) when compared to Galiximab (15% growth inhibition) or Lenalidomide (14% growth inhibition) at 24 hrs. Similar results were observed in other cell lines. In addition, an improvement in galiximab-associated ADCC was observed in lenalidomide-exposed NHL cells. In vivo treatment of SCID mice with lenalidomide in combination with galiximab led to prolongation of the median survival (39 days, 35–42 95% C.I.) compared to galiximab (28 days, 26–29 95% C.I.) or Lenalidomide (23 days, 22–25 95% C.I.) alone ((p<0.01). Conclusions: Our current research demonstrates that Lenalidomide when added to galiximab has augmented in vitro antitumor activity (i.e, antiproliferation and ADCC) and synergistic effects in vivo (i.e., prolongation of survival compared to either monotherapy). Our promising preclinical results of the unique combination of lenalidomide plus galiximab supports future evaluation of this doublet as a clinical trial. (Supported by USPHS grant PO1-CA103985 from the National Cancer Institute.)


PLoS ONE ◽  
2018 ◽  
Vol 13 (12) ◽  
pp. e0208709 ◽  
Author(s):  
Silvia Da Ros ◽  
Luca Aresu ◽  
Serena Ferraresso ◽  
Eleonora Zorzan ◽  
Eugenio Gaudio ◽  
...  

2012 ◽  
Vol 209 (2) ◽  
pp. 291-305 ◽  
Author(s):  
Likun Du ◽  
Roujun Peng ◽  
Andrea Björkman ◽  
Noel Filipe de Miranda ◽  
Cornelia Rosner ◽  
...  

Cernunnos is involved in the nonhomologous end-joining (NHEJ) process during DNA double-strand break (DSB) repair. Here, we studied immunoglobulin (Ig) class switch recombination (CSR), a physiological process which relies on proper repair of the DSBs, in B cells from Cernunnos-deficient patients. The pattern of in vivo generated CSR junctions is altered in these cells, with unusually long microhomologies and a lack of direct end-joining. The CSR junctions from Cernunnos-deficient patients largely resemble those from patients lacking DNA ligase IV, Artemis, or ATM, suggesting that these factors are involved in the same end-joining pathway during CSR. By screening 269 mature B cell lymphoma biopsies, we also identified a somatic missense Cernunnos mutation in a diffuse large B cell lymphoma sample. This mutation has a dominant-negative effect on joining of a subset of DNA ends in an in vitro NHEJ assay. Translocations involving both Ig heavy chain loci and clonal-like, dynamic IgA switching activities were observed in this tumor. Collectively, our results suggest a link between defects in the Cernunnos-dependent NHEJ pathway and aberrant CSR or switch translocations during the development of B cell malignancies.


2020 ◽  
Vol 52 (4) ◽  
pp. 401-410
Author(s):  
Mengyu Xi ◽  
Wan He ◽  
Bo Li ◽  
Jinfeng Zhou ◽  
Zhijian Xu ◽  
...  

Abstract Diffuse large B-cell lymphoma (DLBCL) is the most common category and disease entity of non-Hodgkin lymphoma. Osalmide and pterostilbene are natural products with anticancer activities via different mechanism. In this study, using a new synthetic strategy for the two natural products, we obtained the compound DCZ0801, which was previously found to have anti-multiple myeloma activity. We performed both in vitro and in vivo assays to investigate its bioactivity and explore its underlying mechanism against DLBCL cells. The results showed that DCZ0801 treatment gave rise to a dose- and time-dependent inhibition of cell viability as determined by CCK-8 assay and flow cytometry assay. Western blot analysis results showed that the expression of caspase-3, caspase-8, caspase-9 and Bax was increased, while BCL-2 and BCL-XL levels were decreased, which suggested that DCZ0801 inhibited cell proliferation and promoted intrinsic apoptosis. In addition, DCZ0801 induced G0/G1 phase arrest by downregulating the protein expression levels of CDK4, CDK6 and cyclin D1. Furthermore, DCZ0801 exerted an anti-tumor effect by down-regulating the expressions of p-PI3K and p-AKT. There also existed a trend that the expression of p-JNK and p-P38 was restrained. Intraperitoneal injection of DCZ0801 suppressed tumor development in xenograft mouse models. The preliminary metabolic study showed that DCZ0801 displayed a rapid metabolism within 30 min. These results demonstrated that DCZ0801 may be a new potential anti-DLBCL agent in DLBCL therapy.


2019 ◽  
Vol 116 (34) ◽  
pp. 16981-16986 ◽  
Author(s):  
Claudio Scuoppo ◽  
Jiguang Wang ◽  
Mirjana Persaud ◽  
Sandeep K. Mittan ◽  
Katia Basso ◽  
...  

To repurpose compounds for diffuse large B cell lymphoma (DLBCL), we screened a library of drugs and other targeted compounds approved by the US Food and Drug Administration on 9 cell lines and validated the results on a panel of 32 genetically characterized DLBCL cell lines. Dasatinib, a multikinase inhibitor, was effective against 50% of DLBCL cell lines, as well as against in vivo xenografts. Dasatinib was more broadly active than the Bruton kinase inhibitor ibrutinib and overcame ibrutinib resistance. Tumors exhibiting dasatinib resistance were commonly characterized by activation of the PI3K pathway and loss of PTEN expression as a specific biomarker. PI3K suppression by mTORC2 inhibition synergized with dasatinib and abolished resistance in vitro and in vivo. These results provide a proof of concept for the repurposing approach in DLBCL, and point to dasatinib as an attractive strategy for further clinical development in lymphomas.


2020 ◽  
Vol 8 (Suppl 2) ◽  
pp. A51.2-A52
Author(s):  
A Dalla Pietà ◽  
E Cappuzzello ◽  
P Palmerini ◽  
R Sommaggio ◽  
G Astori ◽  
...  

BackgroundCytokine-Induced Killer (CIK) cells are a population of effector cells that represents a promising tool for adoptive cell therapy. They are easily expandable ex-vivo, safe, and exert cytotoxicity against a broad range of tumor histotypes.1 We recently reported that they have a relevant expression of FcγRIIIa (CD16a), which can be exploited in combination with clinical-grade monoclonal antibodies (mAbs) to redirect their cytotoxicity in an antigen-specific manner, to improve their antitumor activity.2 Indeed, the engagement of CD16a on CIK cells leads to a potent antibody-dependent cell-mediated cytotoxicity (ADCC) against ovarian cancer both in vitro and in vivo. Based on this observation, we investigated whether CIK cells can be specifically retargeted against B-cell malignancies by combination with anti-CD20 mAbs, namely Rituximab® (RTX) and Obinutuzumab® (OBI).Materials and MethodsCIK cells were obtained from peripheral blood mononuclear cells of healthy donors, and stimulated in vitro with IFN-γ, CD3 mAb and IL-2 for 14 days; fresh IL-2 was provided every 3–4 days. CIK cell phenotype was analyzed by multicolor flow cytometry; cytotoxic activity was assessed by calcein AM-release assay against B-cell lines, primary samples and patient-derived xenografts (PDX) obtained from B-cell lymphoma patients after written informed consent.ResultsThe combination with both RTX and OBI significantly increased specific CIK cells lysis against several CD20-expressing lymphoma B cell lines, primary tumors from B-cell lymphoma patients and an established PDX, compared to the combination with a control mAb (cetuximab, CTX). NK-depletion demonstrated that the mAb-mediated cytotoxicity is accountable to the CIK cells fraction within the bulk population since no difference in the lytic activity was detectd in the absence of NK cells. In addition, these results are further supported by in vivo preliminary experiments where the treatment with CIK cells in combination with OBI extensively reduced the growth of PDX and increased mice survival, compared to CIK cells or OBI administered alone.ConclusionsHere we proved that CIK cells can be retargeted with clinical-grade mAbs against CD20-expressing lymphomas. These data indicate that the combination of CIK cells with mAbs can represent a novel approach for the treatment of haematological malignancies.ReferencesFranceschetti M, Pievani A, Borleri G, Vago L, Fleischhauer K, Golay J, et al. Cytokine-induced killer cells are terminally differentiated activated CD8 cytotoxic T-EMRA lymphocytes. Exp Hematol 2009;37:616–28.Cappuzzello E, Tosi A, Zanovello P, Sommaggio R, Rosato A. Retargeting cytokine-induced killer cell activity by CD16 engagement with clinical-grade antibodies. Oncoimmunology 2016 Aug;5(8):e1199311.The research leading to these results has received funding from Fondazione AIRC under IG 2018 - ID. 21354 project - P.I. Rosato AntonioDisclosure InformationA. Dalla Pietà: None. E. Cappuzzello: None. P. Palmerini: None. R. Sommaggio: None. G. Astori: None. K. Chieregato: None. O. Perbellini: None. M. Tisi: None. C. Visco: None. M. Ruggeri: None. A. Rosato: None.


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