Kooperativer Bibliotheksverbund

In: Journal of Clinical Oncology, American Society of Clinical Oncology (ASCO), Vol. 36, No. 19 ( 2018-07-01), p. 1973-1980

Abstract: Venetoclax is an orally bioavailable B-cell lymphoma 2 inhibitor. US Food and Drug Administration and European Medicines Agency approval for patients with 17p deleted relapsed/refractory chronic lymphocytic leukemia [del(17p) CLL] was based on results from 107 patients. An additional 51 patients were enrolled in a safety expansion cohort. Extended analysis of all enrolled patients, including the effect of minimal residual disease (MRD) negativity on outcome, is now reported. Patients and Methods Overall, 158 patients with relapsed/refractory or previously untreated (n = 5) del(17p) CLL received venetoclax 400 mg per day after an initial dose ramp up. Responses were based on 2008 International Workshop on Chronic Lymphocytic Leukemia criteria, with monthly physical exams and blood counts. Computed tomography scan was mandatory at week 36, after which assessment made was by clinical evaluation. Marrow biopsy was performed when complete remission was suspected. MRD was assessed by flow cytometry. Results Patients had a median of two prior therapies (range, zero to 10 therapies), 71% had TP53 mutation, and 48% had nodes that were ≥ 5 cm. Median time on venetoclax was 23.1 months (range, 0 to 44.2 months) and median time on study was 26.6 months (range, 0 to 44.2 months). For all patients, investigator-assessed objective response rate was 77% (122 of 158 patients; 20% complete remission) and estimated progression-free survival at 24 months was 54% (95% CI, 45% to 62%). For 16 patients who received prior kinase inhibitors, objective response rate was 63% (10 of 16 patients) and 24-month progression-free survival estimate was 50% (95% CI, 25% to 71%). By intent-to-treat analysis, 48 (30%) of 158 patients achieved MRD below the cutoff of 10 −4 in blood. Common grade 3 and 4 adverse events were hematologic and managed with supportive care and/or dose adjustments. Conclusion Venetoclax achieves durable responses and was well tolerated in patients with del(17p) CLL. A high rate of blood MRD 〈 10 −4 was achieved in this high-risk population.

Type of Medium: Online Resource

ISSN: 0732-183X , 1527-7755

URL: Article

DOI: 10.1200/JCO.2017.76.6840

Language: English

Publisher: American Society of Clinical Oncology (ASCO)

Publication Date: 2018

detail.hit.zdb_id: 2005181-5

In: Blood, American Society of Hematology, Vol. 124, No. 21 ( 2014-12-06), p. 1991-1991

Abstract: CLL with deletion 17p (17p-) or refractory to fludarabine (F)-based regimens is characterized by poor prognosis. The cooperative French/German CLL2O study aimed at achieving deep and durable response in this population by combining alemtuzumab (A) and dexamethasone (D) induction, followed by consolidation with A maintenance or allogeneic stem-cell transplantation (allo-SCT). Induction treatment consisted of subcutaneous A (30mg, 3x weekly) combined with oral D (40 mg days 1-4 and 15-18), both at 28 day cycles, and prophylactic pegfilgrastim 6 mg on days 1 and 15. If at least SD was achieved after 3 cycles, consolidation was scheduled with either allo-SCT or A maintenance (30mg every 2 weeks for up to 2 years), at discretion of pt and physician. Between January 2008 and December 2011, 131 eligible pts were enrolled at 26 centers. Pts were generally subdivided for this analysis into three cohorts: 17p- 1st line, 17p- relapsed (not refractory) and refractory (i.e. no response or relapse within 6 months) to F-based or similar (i.e. pentostatin, cladribine, bendamustine) therapy. All three cohorts where characterized by high-risk baseline disease features (detailed in Table). During induction, a total of 467 non-hematologic AEs were recorded, predominantly (79%) of minor grade, while 36%, 43%, and 50% of pts in the 3 cohorts had at least one event of grade 3 or higher (Table). ORR (best response) was high in all three cohorts, but CRs were rarely observed outside the 17p- 1st line cohort (Table). Correspondingly, there were marked differences in PFS and OS between the three cohorts with far better outcome in the 17p- 1st line group (see Table and Figure 1). Consolidation treatment was performed as A maintenance (median duration 42 weeks, range 2 – 112.4) in 37%, and allo-SCT in 25%, with a median age of 69 and 57 y in these subgroups. The main reasons for going off-study without consolidation were death due to infection in 19 patients (15%), largely from the F-refractory cohort (n=16), with the majority being non-responders to study treatment (n=11); CLL progression (10%), and other toxicity (9%). Five pts who did not receive immediate consolidation treatment per protocol later underwent allo-SCT, 2 of these have died (sepsis, GvHD). During A maintenance, grade 3/4 toxicity consisted of neutropenia in 47% and thrombocytopenia in 12%. Serious (grade 3/4) non-CMV infection occurred in 17%, 10%, 13% in the 3 cohorts. When comparing PFS between A maintenance and allo-SCT, there were 41 (84%) and 16 (48%) events, respectively, significantly favoring SCT (Figure 2). Six pts who started A maintenance later underwent allo-SCT, 4 of them after relapse. After median follow up of 20 months from allo-SCT, 12 pts have died, 7 because of non-relapse mortality and 5 subsequent to CLL progression. In conclusion, the combination of A and D, followed by A maintenance or allo-SCT showed high response rates in ultra high-risk CLL with expected toxicity. For 17p- 1st line treatment, the results compare favorably to FCR (CLL8: ORR 68%, median PFS 11.3 mo). On the other hand, in F-refractory and 17p- relapsed CLL, the high ORR did not translate into prolongation of PFS. Allo-SCT appears to offer superior disease control in eligible patients despite prior A exposure. Overall, this mature trial may serve as a historical benchmark for comparison of novel agents in ultra high-risk CLL. Table 1 Parameter 17p- 1st line 17p- relapsed F-refractory Number of patients 42 28 61 Median age (yrs) 66.5 64 66 Binet C (%) 45 57 77 B symptoms (%) 40 32 31 ECOG 1/2 (%) 38 39 56 Median thymidine kinase (U/l) 35 48.1 27.6 Median β2MG (mg/dl) 3.8 5.1 4.7 Unmutated IGHV (%) 90 93 87 17p- (%) 100 100 49 Prior lines (median) n.a. 2 3 Prior rituximab (%) n.a. 71 93 AEs during induction (grade 3/4) Table 2 All AEs (%) 36 43 50 Neutropenia (%) 24 36 67 Anemia (%) 14 36 21 Thrombocytopenia (%) 12 39 31 Non-CMV infection (%) 19 36 36 CMV infection (%) 7 0 2 Efficacy (median follow-up 41.3 mo) Table 3 ORR (%) 97 79 69 CR (%) 21 4 3 Median PFS (mo) 32.8 10.3 9.7 Median OS (mo) 〉 60.0 21.4 17.3 Figure 1 Figure 1. Figure 2 Figure 2. Disclosures Stilgenbauer: Amgen: Honoraria, Research Funding; Genzyme: Honoraria, Research Funding.

Type of Medium: Online Resource

ISSN: 0006-4971 , 1528-0020

URL: Article

DOI: 10.1182/blood.V124.21.1991.1991

Language: English

Publisher: American Society of Hematology

Publication Date: 2014

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In: Scientific Data, Springer Science and Business Media LLC, Vol. 7, No. 1 ( 2020-05-01)

Abstract: Acquired resistance to chemotherapy is an important clinical problem and can also occur without detectable cytogenetic aberrations or gene mutations. Chronic lymphocytic leukemia (CLL) is molecularly well characterized and has been elemental for establishing central paradigms in oncology. This prompted us to check whether specific epigenetic changes at the level of DNA methylation might underlie development of treatment resistance. We used Illumina Infinium HumanMethylation450 BeadChips to obtain DNA methylation profiles of 71 CLL patients with differential responses. Thirty-six patients were categorized as relapsed/refractory after treatment with fludarabine or bendamustine and 21 of them had genetic aberrations of TP53 . The other 35 patients were untreated at the time of sampling and 15 of them had genetic aberration of TP53 . Although we could not correlate chemoresistance with epigenetic changes, the patients were comprehensively characterized regarding relevant prognostic and molecular markers (e.g. IGHV mutation status, chromosome aberrations, TP53 mutation status, clinical parameters), which makes our dataset a unique and valuable resource that can be used by researchers to test alternative hypotheses.

Type of Medium: Online Resource

ISSN: 2052-4463

URL: Article

DOI: 10.1038/s41597-020-0456-0

Language: English

Publisher: Springer Science and Business Media LLC

Publication Date: 2020

detail.hit.zdb_id: 2775191-0

In: Blood, American Society of Hematology, Vol. 139, No. 9 ( 2022-03-03), p. 1318-1329

Abstract: Despite considerable treatment advances with targeted therapies for patients with chronic lymphocytic leukemia (CLL) deemed high-risk [del(17p) and/or TP53 mutation], the outcome is still inferior compared with other CLL patients. Combining multiple agents with distinct mechanisms of action may further improve outcomes. CLL2-GIVe is an open-label, multicenter trial which enrolled patients with previously untreated CLL with del(17p) and/or TP53 mutation. Patients received induction therapy with obinutuzumab (GA-101), ibrutinib, and venetoclax (GIVe) for cycles 1 through 6 and consolidation therapy with venetoclax and ibrutinib for cycles 7 through 12. Ibrutinib monotherapy was continued for cycles 13 through 36 in patients not reaching a complete response (CR) with serial undetectable minimal residual disease (uMRD) after consolidation. The primary endpoint was CR rate at cycle 15 (final restaging). Secondary endpoints included MRD, survival, and safety. All 41 patients enrolled between September 2016 and August 2018 received study treatment and were included in efficacy and safety populations. With a CR rate of 58.5% at cycle 15, the primary endpoint was met (95% CI: 42.1-73.7; P & lt; .001). At final restaging, 78.0% of patients had uMRD in peripheral blood (PB); 65.9% of patients had uMRD in bone marrow (BM). Estimated progression-free survival (PFS) and overall survival (OS) rates at 24 months were both 95.1%. Adverse events were reported in all patients; most were low grade (grade ≥3: 23.9%). Two deaths were reported (cardiac failure and ovarian carcinoma), neither related to study treatment. The CLL2-GIVe treatment regimen has a manageable safety profile and is a first-line treatment of good efficacy for patients with high-risk CLL.

Type of Medium: Online Resource

ISSN: 0006-4971 , 1528-0020

URL: Article

DOI: 10.1182/blood.2021013208

Language: English

Publisher: American Society of Hematology

Publication Date: 2022

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In: Blood, American Society of Hematology, Vol. 138, No. 7 ( 2021-08-19), p. 544-556

Abstract: Bruton tyrosine kinase (BTK) inhibitors are highly active drugs for the treatment of chronic lymphocytic leukemia (CLL). To understand the response to BTK inhibitors on a molecular level, we performed (phospho)proteomic analyses under ibrutinib treatment. We identified 3466 proteins and 9184 phosphopeptides (representing 2854 proteins) in CLL cells exhibiting a physiological ratio of phosphorylated serines (pS), threonines (pT), and tyrosines (pY) (pS:pT:pY). Expression of 83 proteins differed between unmutated immunoglobulin heavy-chain variable region (IGHV) CLL (UM-CLL) and mutated IGHV CLL (M-CLL). Strikingly, UM-CLL cells showed higher basal phosphorylation levels than M-CLL samples. Effects of ibrutinib on protein phosphorylation levels were stronger in UM-CLL, especially on phosphorylated tyrosines. The differentially regulated phosphopeptides and proteins clustered in pathways regulating cell migration, motility, cytoskeleton composition, and survival. One protein, myristoylated alanine-rich C-kinase substrate (MARCKS), showed striking differences in expression and phosphorylation level in UM-CLL vs M-CLL. MARCKS sequesters phosphatidylinositol-4,5-bisphosphate, thereby affecting central signaling pathways and clustering of the B-cell receptor (BCR). Genetically induced loss of MARCKS significantly increased AKT signaling and migratory capacity. CD40L stimulation increased expression of MARCKS. BCR stimulation induced phosphorylation of MARCKS, which was reduced by BTK inhibitors. In line with our in vitro findings, low MARCKS expression is associated with significantly higher treatment-induced leukocytosis and more pronounced decrease of nodal disease in patients with CLL treated with acalabrutinib.

Type of Medium: Online Resource

ISSN: 0006-4971 , 1528-0020

URL: Article

DOI: 10.1182/blood.2020009165

Language: English

Publisher: American Society of Hematology

Publication Date: 2021

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In: Blood, American Society of Hematology, Vol. 135, No. 26 ( 2020-06-25), p. 2402-2412

Abstract: Genetic parameters are established prognostic factors in chronic lymphocytic leukemia (CLL) treated with chemoimmunotherapy, but are less well studied with novel compounds. We assessed immunoglobulin heavy variable chain (IGHV) mutation status, common genomic aberrations, and gene mutations in 421 untreated patients within the CLL14 trial (NCT02242942), comparing obinutuzumab+chlorambucil (GClb) vs obinutuzumab+venetoclax (VenG). The incidences of genomic aberrations considering the hierarchical model were del(17p) 7%, del(11q) 18%, +12 18%, and del(13q) 35%, whereas IGHV was unmutated in 60% of patients. NOTCH1 mutations were most common (23%), followed by SF3B1 (16%), ATM (13%), and TP53 (10%). Although the overall response rate (ORR) for GClb was lower in patients with del(17p), del(11q), mutated TP53, ATM, and BIRC3, none of these parameters reduced complete remission (CR) rate and ORR with VenG. At a median follow-up of 28 months, del(17p) and mutated TP53 were the only abnormalities with an effect on progression-free survival (PFS) for both treatment groups: GClb (hazard ratio [HR], 4.6 [P & lt; .01]; HR, 2.7 [P & lt; .01], respectively) and VenG (HR, 4.4 [P & lt; .01]; HR, 3.1 [P & lt; .01], respectively). No other factors affected outcome with VenG, whereas for GClb del(11q), BIRC3, NOTCH1, and unmutated IGHV were associated with shorter PFS. Multivariable analysis identified del(17p), del(11q), unmutated IGHV, and mutated TP53, BIRC3, and SF3B1 as independent prognostic factors for PFS with GClb, whereas for VenG, only del(17p) was significant. VenG was superior to GClb across most genetic subgroups. Patients with adverse genetic markers had the strongest benefit from VenG, particularly subjects with unmutated IGHV, which was identified as a predictive factor in a multivariable treatment-interaction analysis.

Type of Medium: Online Resource

ISSN: 0006-4971 , 1528-0020

URL: Article

DOI: 10.1182/blood.2019004492

Language: English

Publisher: American Society of Hematology

Publication Date: 2020

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In: Blood, American Society of Hematology, Vol. 132, No. Supplement 1 ( 2018-11-29), p. 4237-4237

Abstract: Background: Primary cutaneous diffuse large B-cell lymphoma, leg-type (LT-DLBCL) is an extremely aggressive DLBCL subtype typically occurring at lower extremities and with very poor prognosis due to early relapses and refractory (R/R) disease. Previous studies have shown increased BCR dependence in DLBCL being observed in association with the mutation status of BCR associated genes and MYD88. Aim: Primary goal was to assess the clinical course in patients with primary cutaneous DLBCL and to elucidate the potential of alternative treatments with regard to molecular characteristics. Methods: We identified 16 patients with cutaneous DLBCL treated at our center of which 8 patients had typical localization and were histologically confirmed as LT-DLBCL. The other 8 patients showed cutaneous DLBCL at other anatomic sites (DLBCL-OS) and were classified as DLBCL/DLBCL NOS. Three R/R patients received ibrutinib as off-label individual treatment attempt (420 mg daily). We extended the clinical and molecular analysis for the ibrutinib exposed DLBCL by 1 R/R oropharyngeal DLBCL. Specimen from R/R ibrutinib exposed and 3 other patients were analyzed for CD79B, MYD88, CARD11 and BTK mutations by targeted resequencing analysis. PD-1/PD-L1 expression was assessed in 2 cases with relapse after ibrutinib. Treatment was initiated after signed informed consent. Results: The median age at diagnosis was 51 years in DLBCL-OS and 80 years in LT-DLBCL (total range 37-91). Patients received a median of 2 (0-7) treatments and response to last chemotherapy was different for DLBCL-OS (6 complete remissions (CR), 2 R/R) and LT-DLBCL (2CR, 5R/R). One LT-DLBCL patient showed stable disease (SD) without treatment. LT-DLBCL patients showed a significantly shorter median overall survival (OS) (21,5 months vs. not reached, p=0.009). After ibrutinib treatment we observed 1 ongoing CR for 10 months till date for a DLBCL-OS with CD79B p.Y197S and MYD88 L273P mutation and 1 CR for 6 months in a LT-DLBCL being WT for all sequenced genes. However, this patient relapsed with a highly proliferative disease and died shortly after. The 3rd patient with LT-DLBCL had an isolated MYD88 L265P mutation and showed a PR for 1 month. Samples from patients with indolent clinical course showed a MYD88 p.S251N and BTK p.P385S mutation (LT-DLBCL with SD) or were WT for all sequenced genes (2 patients with DLBCL-OS and ongoing CR). The patient with R/R oropharyngeal DLBCL had a MYD88 L265P and CD79B c.587A mutation, 4 prior treatment regimen and fulminant progression during the last 2 treatments. Initial response to ibrutinib was rapid with a drop of LDH levels from 2200 U/L to 620 U/L within 7 days and consecutive decrease to 323 U/L. However, this patient relapsed after 30 days of treatment. Immunomodulatory effects of ibrutinib and potential synergistic treatment with checkpoint inhibitors have previously been suggested. We specifically investigated PD-1/PD-L1 expression in tissues obtained from the two patients progressing after ibrutinib treatment. Remarkably, we observed increased expression for PD-1 (moderate) and PD-L1 (strong) in non-tumor bystander cells. Treatment with nivolumab was initiated in 1 patient with early clinical benefit. However, the patient refused the continuation of this treatment. Conclusion: Patients with LT-DLBCL are older and show a poor clinical course compared to cutaneous DLBCL at other anatomic sites. MYD88 L265P mutations were observed only in chemo-refractory cases with extranodal DLBCL. Ibrutinib can induce complete remissions and sustained responses in chemo-refractory extranodal DLBCL but relapses may be more aggressive and disseminated. Mutational patterns and ibrutinib response were in line with previous hypothetical models for sensitivity to BCR inhibition. Combining ibrutinib and checkpoint inhibitors may be considered in future trials for LT-DLBCL patients. Disclosures Weissinger: Bristol-Myers Squibb: Research Funding. Viardot:Roche: Consultancy, Honoraria; Amgen: Consultancy; Gilead Kite: Consultancy, Honoraria; BMS: Consultancy, Honoraria; Pfizer: Consultancy, Honoraria.

Type of Medium: Online Resource

ISSN: 0006-4971 , 1528-0020

URL: Article

DOI: 10.1182/blood-2018-99-117032

Language: English

Publisher: American Society of Hematology

Publication Date: 2018

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detail.hit.zdb_id: 80069-7

In: Blood, American Society of Hematology, Vol. 141, No. 12 ( 2023-03-23), p. 1425-1441

Abstract: Upregulation of the proto-oncogene T-cell leukemia/lymphoma 1A (TCL1A) is causally implicated in various B-cell and T-cell malignancies. High-level TCL1A correlates with aggressive disease features and inferior clinical outcomes. However, the molecular and cell biological consequences of, particularly nuclear, TCL1A are not fully elucidated. We observed here in mouse models of subcellular site-specific TCL1A-induced lymphomagenesis that TCL1A exerts a strong transforming impact via nuclear topography. In proteomic screens of TCL1A-bound molecules in chronic lymphocytic leukemia (CLL) cells and B-cell lymphoma lines, we identified regulators of cell cycle and DNA repair pathways as novel TCL1A interactors, particularly enriched under induced DNA damage and mitosis. By functional mapping and in silico modeling, we specifically identified the mitotic checkpoint protein, cell division cycle 20 (CDC20), as a direct TCL1A interactor. According to the regulatory impact of TCL1A on the activity of the CDC20-containing mitotic checkpoint and anaphase-promoting complexes during mitotic progression, TCL1A overexpression accelerated cell cycle transition in B-cell lymphoma lines, impaired apoptotic damage responses in association with pronounced chromosome missegregation, and caused cellular aneuploidy in Eμ-TCL1A mice. Among hematopoietic cancers, CDC20 levels seem particularly low in CLL. CDC20 expression negatively correlated with TCL1A and lower expression marked more aggressive and genomically instable disease and cellular phenotypes. Knockdown of Cdc20 in TCL1A-initiated murine CLL promoted aneuploidy and leukemic acceleration. Taken together, we discovered a novel cell cycle–associated effect of TCL1A abrogating controlled cell cycle transition. This adds to our concept of oncogenic TCL1A by targeting genome stability. Overall, we propose that TCL1A acts as a pleiotropic adapter molecule with a synergistic net effect of multiple hijacked pathways.

Type of Medium: Online Resource

ISSN: 0006-4971 , 1528-0020

URL: Article

DOI: 10.1182/blood.2022015494

Language: English

Publisher: American Society of Hematology

Publication Date: 2023

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In: Blood, American Society of Hematology, Vol. 124, No. 3 ( 2014-07-17), p. 420-425

Abstract: Increased PTK2 expression is associated with improved outcomes in patients with CLL treated with R-FC immunochemotherapy. PTK2 expression represents a useful, novel biomarker for selection of patients who will benefit from R-FC immunochemotherapy.

Type of Medium: Online Resource

ISSN: 0006-4971 , 1528-0020

URL: Article

DOI: 10.1182/blood-2013-12-538975

Language: English

Publisher: American Society of Hematology

Publication Date: 2014

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detail.hit.zdb_id: 80069-7

In: Blood, American Society of Hematology, Vol. 132, No. Supplement 1 ( 2018-11-29), p. 583-583

Abstract: Rationale: The BTK inhibitor ibrutinib has proved to be highly effective in both treatment naїve and refractory or relapsed CLL patients. In contrast to most other therapeutic options, where unmutated IGVH correlates with adverse prognosis, response to ibrutinib is independent of IGVH mutation status. This compulsorily raises the question why CLL cells with an unmutated IGVH are equally susceptible to BTK inhibition. One key aspect might be understanding the global (phospho)proteome of UM-CLL and M-CLL cells which has not been investigated so far. Methods: We performed a comprehensive proteomics and phosphopreoteomics analysis of 14 CLL samples with unmutated or mutated IgVH using quantitative mass spectrometry (MS). ITRAQ labelling and TiO2 enrichment/HILIC fractionation were utilized for this approach. Results: Altogether we identified 9184 phosphopeptides corresponding to 2854 proteins. We found the typical pS:pT:pY ratio, with 89% of all detected phosphopeptides containing a phosphorylated serine (pS), 10% a phosphorylated threonine (pT) and 1% a phosphorylated tyrosine (pY) in CLL samples. Strikingly, UM-CLL showed a higher basal phosphorylation level than M-CLL samples with significantly higher phosphorylation of 92 out of 102 identified proteins (P 〈 0.05) Interestingly, ibrutinib reverted this phosphorylation pattern predominantly in UM-CLL but not M-CLL samples and led to a shift of the ratio towards phosphotyrosine in UM-CLL (pS:pT:pY in %: 30:9:61) but not in M-CLL (pS:pT:pY: 78:7:15). Most of the indentified phosphopeptides clustered in pathways that regulate migration and motility and cell survival and death. Regarding the BCR pathway, we identified known and novel p-sites: Lyn (8 sites), PIK3AP1 (5), PLCG2 (5), Syk (4), BLK (4), PIK3R4 (2), LCK (2), BTK (1), PIK3C2B (1), PIK3C3 (1), PIK3CD (1). In this context a novel molecule, MARCKS attracted our attention. We identified three different p-sites (S101, T150 and S170) which were differentially phosphorylated in M-CLL and UM-CLL. Moreover, our proteome approach revealed distinct expression levels of 38 proteins out of 3466 isolated proteins between the two groups (1,5-fold changes; P 〈 0.01), among them MARCKS. Expression of MARCKS was significantly higher in M-CLL samples. MARCKS, a PKC substrate, was shown to play a critical role in invasiveness and metastasis of various cancer types, but its role in CLL is unclear. Since MARCKS has not been associated with CLL, we proved our findings from MS in a larger cohort of CLL patients both on protein level (n=36) and on transcription level (n=337). Strikingly, shorter PFS of CLL patients (n=337) undergoing chemoimmunotherapy correlates with low expression of MARCKS independently of the mutational status. We further investigated the cellular function of MARCKS in CLL cells utilizing CRISPR/Cas9 to generate KO cells. We were able to show that MARCKS regulates migration towards CXCL12 and that a loss of MARCKS leads to significantly increased migration. As MARCKS is upstream of AKT at the plasma membrane, we wondered if its expression might be relevant for AKT signalling. Importantly, we found that AKT phosphorylation (S473) was significantly upregulated in MARCKS KO cells indicating that MARCKS is involved in AKT regulation. Since MARCKS seems to be involved in tumor microenvironment (TME) interaction, we determined the influence of TME stimuli on MARCKS regulation. Interestingly, MARCKS was upregulated by CD40:CD40L interaction but phosphorylated upon BCR stimulation in both M-CLL and UM-CLL as assessed by immunoblot. Furthermore, we identified MARCKS to be targeted by ibrutinib, as phosphorylation at S170 was reduced upon ibrutinib treatment. Conclusion: For the first time we could show a comprehensive picture of the phosphoproteome and proteome of UM-CLL and M-CLL samples. Strikingly, the basal phosphorylation level was significantly higher in UM-CLL and was more susceptible to ibrutinib treatment. Our findings reveal a relevant association of MARCKS expression with CLL prognosis, supported by the functional evidence that MARCKS acts upstream as novel modulator of AKT signalling and controls migration towards CXCL12. These data indicate that MARCKS is a novel and relevant target of ibrutinib especially in the context of the TME. Disclosures Bahlo: Roche: Honoraria, Other: Travel Grants. Fischer:Roche: Other: Travel support. Wendtner:Roche: Consultancy, Honoraria, Other: travel support, Research Funding; Janssen: Consultancy, Honoraria, Other: travel support, Research Funding; Gilead: Consultancy, Honoraria, Research Funding; Genetech: Consultancy, Honoraria, Other: travel support, Research Funding; GlaxoSmithKline: Consultancy, Honoraria, Other: travel support, Research Funding; Abbvie: Consultancy, Honoraria, Other: travel support, Research Funding; Mundipharma: Consultancy, Honoraria, Research Funding; MorphoSys: Consultancy, Honoraria, Other: travel support, Research Funding; Pharmacyclics: Consultancy, Honoraria, Other: travel support, Research Funding; Gilead: Consultancy, Honoraria, Other: travel support, Research Funding. Stilgenbauer:Pharmcyclics: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; AbbVie: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Genzyme: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Mundipharma: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Genentech: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; GSK: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Sanofi: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Boehringer-Ingelheim: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Gilead: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Hoffmann La-Roche: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Hallek:Pharmacyclics: Honoraria, Research Funding; Celgene: Honoraria, Research Funding; Mundipharma: Honoraria, Research Funding; Janssen: Honoraria, Research Funding; Gilead: Honoraria, Research Funding; Abbvie: Honoraria, Research Funding; Roche: Honoraria, Research Funding.

Type of Medium: Online Resource

ISSN: 0006-4971 , 1528-0020

URL: Article

DOI: 10.1182/blood-2018-99-118235

Language: English

Publisher: American Society of Hematology

Publication Date: 2018

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