Peptide-Receptor Radiotherapy with CXCR4-Targeting Pentixather Reduces Leukemia Burden in Acute Leukemia PDX and Patients

Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 4055-4055 ◽  
Author(s):  
Stefan Habringer ◽  
Peter Herhaus ◽  
Margret Schottelius ◽  
Constantin Lapa ◽  
Rouzanna Istvanffy ◽  
...  

Abstract Introduction: The G-protein coupled CXC-motif Chemokine Receptor 4 (CXCR4) and its ligand CXCL12 are master regulators of cell migration, organogenesis and maintenance of the hematopoietic stem/progenitor cell (HSPC) niche. However, CXCR4 also drives survival, proliferation and metastasis of cancer cells and its expression is associated with adverse prognosis in a broad range of malignancies, including acute myeloid and lymphoblastic leukemia (AML, ALL). Despite of high rates of complete remissions after induction chemotherapy, AML, and to a lesser extend ALL, frequently relapse with a more aggressive phenotype and require highly active therapies to reduce leukemic burden before allogeneic stem cell transplantation (alloSCT). We recently showed that CXCR4-directed PET imaging with 68Ga-Pentixafor is feasible in AML patients, providing first evidence for the potential of CXCR4-directed theranostics (Herhaus, Habringer et al., Haematologica 2016). Methods: We used patient-derived xenograft (PDX) and cell line xenograft mouse models of AML and ALL to evaluate the efficacy and toxicity of a CXCR4-targeted peptide receptor radiotherapy (PRRT) theranostic approach with the CXCR4-binding PET tracer 68Ga-Pentixafor and its b-emitting therapeutic counterpart 177Lu-Pentixather. We analyzed bone marrow (BM), spleen, blood (PB) and liver of treated PDX mice by flow cytometry, immunohistochemistry and radioactive biodistribution assays. The toxicity to the murine BM HSPC and the hematopoietic niche was assessed via flow cytometry, colony forming unit assays, isolation and differentiation of BM mesenchymal stem cells (MSCs) and co-culture experiments. We provide first evidence for this highly innovative CXCR4-directed theranostic approach in patients with AML who relapsed after alloSCT and had no other established treatment options. Results: We generated PDX models of acute leukemia patients in NSG mice that required intact CXCR4 signaling for disease initiation and progressively infiltrated spleen, BM and PB. 68Ga-Pentixafor PET imaging enabled visualization of CXCR4-positive leukemic burden in spleen and BM of acute leukemia PDX and cell line xenografts. In ALL PDX, CXCR4-directed PRRT with 177Lu-Pentixather rapidly distributed to leukemia-harboring organs, which lead to significant accumulation of radioactivity in spleen and BM. 177Lu-Pentixather therapy resulted in efficient eradication or significant reduction of leukemic infiltration in PB, spleen and BM. Spleen size was reduced dramatically as early as 24hr after initiation of PRRT. Treated mice suffered severe suppression of BM function as evidenced by therapy-induced severe cytopenia affecting mature CD45+ blood cells and colony-forming unit potential of progenitors in the BM. To assess the damage to the BM niche, we isolated MSCs of 177Lu-Pentixather treated mice compared to control. We found that MSCs from 177Lu-Pentixather-treated mice were still viable and proliferated in vitro. Importantly, treated MSCs were still capable of supporting normal lineage-marker negative murine HSPC and induced their differentiation into mature leukocytes in co-culture. Finally, we treated patients with refractory AML after alloSCT and multiple failed treatment regimens, who had no further established treatment options with CXCR4 PRRT followed by a conventional conditioning regimen and second alloSCT. Our data indicate that CXCR4 targeting and the inevitable and desired cross-fire effect of 177Lu-Pentixather PRRT could be a highly efficient means to eradicate leukemia and to induce myeloablation. This approach could serve as a valuable addition to conditioning protocols in alloSCT. Conclusion: In conclusion, our work provides first evidence for the efficacy of the novel CXCR4-directed agent 177Lu-Pentixather in acute leukemia PDX models and in a proof-of-concept individual treatment approach in one patient relapsed after standard alloSCT. Importantly, these findings can directly be translated into clinical studies in patients and provide crucial information regarding efficacy and toxicity. A phase I/II study to integrate CXCR-directed PRRT into conditioning regimens is planned. Disclosures Peschel: MophoSys: Honoraria. Wester:Scintomics GmbH: Employment, Other: CEO.

Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 3004-3004 ◽  
Author(s):  
Julia B. Schueler ◽  
Dagmar Wider ◽  
Kerstin Klingner ◽  
Gabrielle Melanie Siegers ◽  
Annette M May ◽  
...  

Abstract Background Appropriate animal models for hematological malignancies are highly attractive, because they allow the study of the tumor biology and underlying disease mechanisms. They also constitute a major prerequisite for rapid bench-to-bedside translation of investigational anticancer therapies. To validate our multiple myeloma patient (pt)-derived xenograft (MM PDX) model (Schueler et al, Expert Opin Biol Ther, 2013), we systematically analyzed a panel of MM PDX with regard to their sensitivity towards standard of care treatment and compared these data with the pts' clinical outcome. Methods Bone marrow (BM) cells of 11 MM pts were implanted intratibialy (i.t.) into 103 NOD/Shi-scid/IL-2Rγnull (NOG) mice (n= 6-18 / pt sample). Mice were treated according to pts' therapy with VCD (Bortezomib, Cyclophosphamide, Dexamethasone), or to evaluate additional treatment options with Rd (Lenalidomide, Dexamethasone). Tumor growth and antitumoral activity in mice were assessed in tumor-bearing mice and compared to untreated control mice as well as to pts' response. Tumor growth in the mouse model was monitored by whole-body fluorescence-based in-vivo-imaging (IVI) using CF750-labeled α-HLA ABC antibody before and during treatment as well as 24h after last treatment cycle as described (Schueler J. PLOSone 2013). Mock-injected animals served as negative controls. Engraftment of human MM cells in murine organs was confirmed by flow cytometry and patho-histological analyses (immunostaining) at the end of the study. Results The pt cohort included a typical MM clientele for referral centers, with a median age of 75 years (range 56-85), median BM infiltration of 80% (20-90), and high- and standard-risk cytogenetics in 5 and 6 pts, respectively. All pts had advanced disease with Durie&Salmon stage III and active/symptomatic MM. All pts received VCD after diagnosis and BM sampling. MM cell engraftment could reliably be determined from experimental day 10 on in all 11 MM PDX models, at all assessed sites, namely within the BM, spleen and peripheral blood (PB) of recipient mice. Individual pt samples displayed distinct tumor growth patterns in vivo. Fluorescence intensity of engrafted murine organs ranged from 2- to 15-fold compared to mock injected control mice. Mean IVI signals in BM of recipient mice were 10-fold higher as compared to spleen signals, qualifying the BM niche as the preferred homing localization of pts' MM cells. Of note, both injected and non-injected BM sites were infiltrated by MM cells 10 days after tumor cell injection. Engraftment of human MM cells in the respective murine organs was confirmed by flow cytometry (HLA ABC, CD138, CD38) and histology and verified MM engraftment via both methods, confirming prior reports (Schüler PLOSone 2013; Groen Blood 2012;120:e9-16, Overdijk MAbs. 2015;7:311-21). The murine engraftment capacity was independent of MM type, disease stage, BM infiltration and cytogenetics of the donor pt. VCD was applied to 9 different MM PDX models and induced partial remission (PR; defined as at least 50% reduction of murine tumor load in BM, spleen and/or PB) in 5 out of 9 tested MM PDX models, whereas 2 cases each showed stable disease (SD) or progression (PD). The response rates in the mouse avatars mirrored the clinical outcome of the respective MM pts in 8/9 cases; only one MM pt showed serological and clinical PR, whereas the corresponding mice displayed SD. Rd induced PR in 1 and PD in a second MM PDX model, underlining the feasibility of MM PDX for drug screening approaches. Conclusions Due to the complex tumor biology, murine models of MM are still challenging. Our data support the preclinical rationale to use i.t.-injected NOG mice, since they closely resemble clinical MM with respect to symptoms, disseminated disease sites and response to anticancer treatment. Possible applications for the MM mouse avatars include development of new anticancer drugs as well as definition of biomarker strategies and selection of treatment options for individual pts with relapsed/refractory MM. The data of our preclinical study may serve as a useful future strategy to guide treatment decisions in refractory pts. The suitability as a drug development tool will be additionally determined performing treatment experiments with novel agents, e.g. elotuzumab or daratumumab. Disclosures Schueler: Oncotest GmbH: Employment. Klingner:Oncotest GmbH: Employment.


Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 2538-2538
Author(s):  
Eva Oswald ◽  
Gabriele Greve ◽  
Kerstin Klingner ◽  
Benedikt Hammerich ◽  
Dorothee Lenhard ◽  
...  

Abstract Many efforts are made to treat acute leukemia effectively, but still; new treatment options are urgently needed. In the past, mainly chemically induced and cell line-derived mouse models were used to evaluate the efficacy of new drugs. The high failure rate of 96% in early clinical development illustrates the urgent need for more predictive preclinical models as a major prerequisite for rapid bench-to-bedside translation of investigational anticancer therapies. Transplantable patient-derived xenograft (PDX) models of leukemia offer a strong preclinical tool for drug screening and biomarker development as they represent the complex clinical tumor heterogeneity and molecular diversity of human cancer. Between 2011 and 2015 we collected 91 samples of peripheral blood (PB) or bone marrow (BM) from patients diagnosed with acute myeloid or lymphoblastic leukemia (AML, ALL) and injected them intratibially (i.t.) into NOG (NOD/Shi-scid/IL-2Rγnull) mice (n=1-5/patient sample). Infiltration of human leukemic cells was determined by flow cytometry in murine PB, BM and spleen. If more than 5% of hCD45+, hCD33+, hCD34+, hCD38+, and/or HLA-ABC+ cells were detectable in one sample, it was classified as engrafted. Results were confirmed by histo-pathological examination. FISH analyses confirmed the cytogenetical concordance with the donor patient where available. 8 models were treated with cytarabine and results were compared to patient´s outcome and treatment experiments using cell line derived models of AML. Whole exome sequencing analyses of the transplantable models are underway for a deeper characterization of the respective leukemic clone which adapted to the murine microenvironment. Specimens of 44 female and 47 male patients (median age: 59 years, median BM infiltration: 39%) were collected. The donor patient cohort covered a broad range of different molecular subtypes: amongst others 5 MLL-rearrangements, 1 MLL-Deletion, 2 t(8;21) translocations, 20 cytogenetically normal and 7 complex karyotypes were included. Up to now 12 PDX models were in passage (P) 5 and higher, where P1 represents first implantation of human cells into the murine BM. 15 PDX models grew in P3 - P4, 21 in P2, 36 in P1 and 7 samples showed no engraftment. Engraftment capacity of the leukemic cells did not correlate significantly with any of the patient characteristics. BM engraftment ranged from 30% - 80%. Spleen and PB depicted 5 - 30% of leukemic cells. Infiltration rate in different organs and immuno-phenotypic characteristics of the human cells were specific for a defined model and preserved during serial transplantation. Take rates within one mouse cohort in serial transplantation were ≥98% for all transplantable PDX, similar to cell line derived models thereby qualifying the PDX approach as a suitable preclinical platform. Overall survival (OS) in P1 ranged from 52 to > 310 days (d). Models which could be serially transplanted showed model specific median OS ranging from 32 - 150 d. Comparable cell line derived models depicted median OS of 13 - 45 d. Of note, cell line derived models (KG-1, NOMO-1, MOLM-13, THP-1, MV4-11 or HL60, n ≥ 10 mice/cell line) induced hind limb paresis in all recipient mice. These symptoms could not be observed in PDX and most important are not part of the clinical picture. Cytarabine induced a significantly prolonged OS in 8/8 tested PDX models. Respective donor patients showed hematologic response under cytarabine based therapy highlighting the excellent predictivity of the in vivo platform. In contrast none of the investigated cell line derived models showed sensitivity towards cytarabine, although representing similar subtypes of AML as the investigated PDX models. Taken together a constantly expanding panel of well characterized AML/ALL PDX covering a broad range of different subtypes of the disease is available for drug development and tumorbiology studies. The comparison with cell line derived in vivo models revealed significant advantages of the PDX approach as the latter represents the molecular diversity more in detail, mimics the clinical signs of leukemia more realistic and most important mirrors sensitivity towards standard of care in a direct comparison with the donor patient´s clinical outcome. Therefore, we strongly believe that the AML/ALL PDX platform is a robust and predictive tool to address translational challenges in oncology research. Disclosures Oswald: Oncotest GmbH: Employment. Klingner:Oncotest GmbH: Employment. Lenhard:Oncotest GmbH: Employment. Schueler:Oncotest GmbH: Employment.


Blood ◽  
2021 ◽  
Vol 138 (Supplement 1) ◽  
pp. 377-377
Author(s):  
Maryam Ghalandary ◽  
Yuqiao Gao ◽  
Martin Becker ◽  
Diana Amend ◽  
Klaus H. Metzeler ◽  
...  

Abstract Background: The prognosis of patients with acute myeloid leukemia (AML) remains poor and novel therapeutic options are intensively needed. Targeted therapies specifically address molecules with essential function for AML and deciphering novel essential target genes is of utmost importance. Functional genomics via CRISPR\Cas9 technology paves the way for the systematic discovery of novel essential genes, but was so far mostly restricted to studying cell lines in vitro, lacking features of, e.g., primary tumor cells and the in vivo tumor microenvironment. To move closer to the clinical situation in patients, we used the CRISPR\Cas9 technology in patient-derived xenograft (PDX) models of AML in vivo. Methods: Primary tumor cells from seven patients with AML were transplanted into immunocompromised NSG mice and serially transplantable PDX models derived thereof. PDX models were selected which carry the AML specific mutations of interest at variant allele frequencies close to 0.5. PDX cells were lentivirally transduced to express the Cas9 protein and a sgRNA; successfully transduced PDX cells were enriched by flow cytometry gating on a recombinant fluorochrome or by puromycin. The customized sgRNA library was designed using the CLUE (www.crispr-clue.de) platform and cloned into a lentiviral vector with five different sgRNAs per target gene, plus positive and negative controls (Becker et al., Nucleic Acids Res. 2020). PDX cells were lentivirally transduced with the CRISPR/Cas9 sgRNA library, transplanted into NSG mice, grown in vivo and cells re-isolated at advanced AML disease. sgRNA distribution was measured by next generation sequencing and compared to input control using the MAGeCK pipeline. Interesting dropout hits from PDX in vivo screens were validated by fluorochrome-guided competitive in vivo experiments in the PDX models, comparing growth of PDX AML cells with knockout of the gene of interest versus control knockout in the same mouse. PDX cells were transduced with lentiviral vectors expressing a single sgRNA, using in parallel three different sgRNAs per target gene. Targeting and control sgRNAs were marked by different fluorochromes; PDX cells expressing targeting or control sgRNA were mixed at a 1:1 ratio, injected into NSG mice and PDX models competitively grown until advanced disease stage, when cell distributions was determined by flow cytometry. Human AML cell lines were studied in vitro for comparison. Results: In search for genes with essential function in AML, we cloned a small customized sgRNA library targeting 34 genes recurrently mutated in AML and tested the library in two PDX AML models in vivo. From the dropouts, we validated most interesting target genes using fluorochrome-guided competitive in vivo assays. Knockout of NPM1 abrogated in vivo growth in all PDX AML models tested, reproducing the known common essential function of NPM1. KRAS proved an essential function in PDX AML models both with and without an oncogenic mutation in KRAS, although with a stronger effect upon KRAS mutation, suggesting that patients with tumors both with and without KRAS mutation might benefit from treatment inhibiting KRAS. Surprising results were obtained for WT1 and DNMT3A. Both genes are frequently mutated in AML, but most AML cell lines tested in vitro do not show an essential function of any of the two genes, in published knockdown or knockout data, including from the Cancer Dependency Map database. On the contrary, knockout of either WT1 or DNMT3A was shown to enhance growth of AML cell lines and increase leukemogenesis in certain models. In PDX models in vivo, we found a clearly essential function for DNMT3A in all AML samples and WT1 in most samples tested and PDX in vivo results were discordant to cell line in vitro data, suggesting that cell line inherent features and/or the in vivo environment influence the function of WT1 and DNMT3A. Conclusion: We conclude that functional genomics in PDX models in vivo allows discovering essentialities hidden for cell line in vitro approaches. WT1 and DNMT3A harbor the potential to represent attractive therapeutic targets in AML under in vivo conditions, warranting further evaluation. Disclosures No relevant conflicts of interest to declare.


Cancers ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 3871
Author(s):  
Emma Rodriguez ◽  
Guangsheng Pei ◽  
Sang T. Kim ◽  
Alexis German ◽  
Prema Robinson

Although cisplatin is very effective as a treatment strategy in triple-negative breast cancer (TNBC), it has unwarranted outcomes owing to recurrence, chemoresistance and neurotoxicity. There is critically important to find new, effective and safe therapeutics for TNBC. We determined if SP-receptor antagonism in combination with cisplatin may serve as a novel, more efficacious and safer therapeutic option than existing therapies for TNBC. We used a neuronal cell line (PC12) and two TNBC cell lines (Sum 185 and Sum 159) for these studies. We determined that the levels of cells expressing the high-affinity SP-receptor (neurokinin 1 receptor (NK1R)), as determined by flow-cytometry was significantly elevated in response to cisplatin in all three cells. We determined that treatment with aprepitant, an SP-receptor antagonist decreased cisplatin-induced, loss of viability (studied by MTT assay), production of reactive oxygen species (by DCFDA assay) and apoptosis (by flow-cytometry) in PC12 cells while it was increased in the two TNBC cells. Furthermore, we demonstrated that important genes associated with metastases, inflammation, chemoresistance and cell cycle progression are attenuated by SP-receptor antagonism in the TNBC cell line, Sum 185. These studies implicate that SP-receptor antagonism in combination with cisplatin may possibly serve as a novel, more efficacious and safer therapeutic option than existing therapies for TNBC.


Blood ◽  
1985 ◽  
Vol 65 (1) ◽  
pp. 21-31 ◽  
Author(s):  
RC Stong ◽  
SJ Korsmeyer ◽  
JL Parkin ◽  
DC Arthur ◽  
JH Kersey

Abstract A cell line, designated RS4;11, was established from the bone marrow of a patient in relapse with an acute leukemia that was characterized by the t(4;11) chromosomal abnormality. The cell line and the patient's fresh leukemic cells both had the t(4;11)(q21;q23) and an isochromosome for the long arm of No. 7. Morphologically, all cells were lymphoid in appearance. Ultrastructurally and cytochemically, approximately 30% of the cells possessed myeloid features. The cells were strongly positive for terminal deoxynucleotidyl transferase. They were HLA-DR positive and expressed surface antigens characteristic for B lineage cells, including those detected by anti-B4, BA-1, BA-2, and PI153/3. Immunoglobulin gene analysis revealed rearrangements of the heavy chain and kappa chain genes. The cells lacked the common acute lymphoblastic leukemia antigen and antigenic markers characteristic of T lineage cells. The cells reacted with the myeloid antibody 1G10 but not with other myeloid monoclonal antibodies. Treatment with 12-O-tetradecanoyl- phorbol-13-acetate induced a monocyte-like phenotype demonstrated by cytochemical, functional, immunologic, and electron microscopic studies. The expression of markers of both early lymphoid and early myeloid cells represents an unusual phenotype and suggests that RS4;11 represents a cell with dual lineage capabilities. To our knowledge, RS4;11 is the first cell line established from t(4;11)-associated acute leukemia.


2018 ◽  
Vol 34 (4) ◽  
pp. 2002-2007 ◽  
Author(s):  
Behrooz Afarideh ◽  
Masoumeh Rajabibazl ◽  
Meisam Omidi ◽  
Bahram Yaghmaee ◽  
Azam Rahimpour ◽  
...  

Cancer is one of the greatest health challenges in the world. Every year, many people die because of cancer. Chemotherapy is one of the treatment options in cancer disease. Fluorouracil )5-FU( is one of the chemotherapy dr0075gs, but it has relatively low toxic effect on tumor cells when it is used on free form, which also results in its poor efficacy. GO (graphene oxide) has a single-atomic layer and has several functional groups such as epoxide, carbonyl, carboxyl and hydroxyl which makes it a suitable carrier for drug loading. In the present study, we loaded 5-FU on GO nanocarrier to produce GO/5-FU, and characterized it by FT-IR. CT26 Ds-Red adenocarcinoma cell line was treated with GO/5-FU, free 5-FU, GO, and PBS (Phosphate buffer saline). The results showed significant inhibition of the CT26 Ds-Red cells using GO/5-FU compared to free 5-FU (P<0.05). Therefore, loaded 5-FU on GO (GO/5-FU) could be a new approach for optimization of 5-FU tumor cytotoxicity.


Author(s):  
Christo J. Botha ◽  
Sarah J. Clift ◽  
Gezina C.H. Ferreira ◽  
Mxolisi G. Masango

Geigeria poisoning in sheep, locally known as ‘vermeersiekte’, is an economically important plant poisoning in southern Africa. The toxic principles contained by the toxic plants are believed to be several sesquiterpene lactones, such as geigerin, vermeeric acid and vermeerin, which cause striated muscle lesions in small stock. Because of ethical issues surrounding the use of live animals in toxicity studies, there is currently a dire need to establish an in vitro model that can be used to replace traditional animal experimentation. The objective of this study was to determine the cytotoxicity of geigerin in a murine myoblast cell line (C2C12) using methyl-thiazol-tetrazolium (MTT) and lactate dehydrogenase (LDH) assays, annexin V and propidium iodide (PI) flow cytometry and transmission electron microscopy (TEM). Mouse myoblasts were exposed to 2.0 mM, 2.5 mM and 5.0 mM geigerin for 24, 48 and 72 h. A concentration-dependent cytotoxic response was observed. Apoptosis was detected by means of annexin V flow cytometry during the first 24 h and apoptotic bodies were also visible on TEM. According to the LDH and PI flow cytometry results, myoblast cell membranes were not injured. We concluded that the murine myoblast cell line (C2C12) is a suitable model for future studies planned to evaluate the cytotoxicity of other and combinations of sesquiterpene lactones, with and without metabolic activation, implicated in ‘vermeersiekte’ and to elucidate the subcellular effects of these myotoxins on cultured myoblasts.


10.1251/bpo92 ◽  
2004 ◽  
Vol 6 (1) ◽  
pp. 220-225 ◽  
Author(s):  
Neora Pick ◽  
Scott Cameron ◽  
Dorit Arad ◽  
Yossef Av-Gay

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