scholarly journals Targeting ROR1 identifies new treatment strategies in hematological cancers

2017 ◽  
Vol 45 (2) ◽  
pp. 457-464 ◽  
Author(s):  
Hanna Karvonen ◽  
Wilhelmiina Niininen ◽  
Astrid Murumägi ◽  
Daniela Ungureanu
Keyword(s):  
B Cell ◽  
Molecular Mechanism ◽  
Targeted Therapies ◽  
Lymphoblastic Leukemia ◽  
Treatment Strategies ◽  
Lymphocytic Leukemia ◽  
Orphan Receptor ◽  
Type I ◽  
Cancer Type ◽  
Hematological Cancers

Receptor tyrosine kinase-like orphan receptor 1 (ROR1) is a member of the ROR receptor family consisting of two closely related type I transmembrane proteins ROR1 and ROR2. Owing to mutations in their canonical motifs required for proper kinase activity, RORs are classified as pseudokinases lacking detectable catalytic activity. ROR1 stands out for its selective and high expression in numerous blood and solid malignancies compared with a minimal expression in healthy adult tissues, suggesting high potential for this molecule as a drug target for cancer therapy. Current understanding attributes a survival role for ROR1 in cancer cells; however, its oncogenic function is cancer-type-specific and involves various signaling pathways. High interest in ROR1-targeted therapies resulted in the development of ROR1 monoclonal antibodies such as cirmtuzumab, currently in a phase I clinical trial for chronic lymphocytic leukemia. Despite these advances in translational studies, the molecular mechanism employed by ROR1 in different cancers is not yet fully understood; therefore, more insights into the oncogenic role of ROR1 signaling are crucial in order to optimize the use of targeted drugs. Recent studies provided evidence that targeting ROR1 simultaneously with inhibition of B-cell receptor (BCR) signaling is more effective in killing ROR1-positive leukemia cells, suggesting a synergistic correlation between co-targeting ROR1 and BCR pathways. Although this synergy has been previously reported for B-cell acute lymphoblastic leukemia, the molecular mechanism appears rather different. These results provide more insights into ROR1–BCR combinatorial treatment strategies in hematological malignancies, which could benefit in tailoring more effective targeted therapies in other ROR1-positive cancers.

Ofatumumab, a Novel Anti-CD20 Monoclonal Antibody for the Treatment of B-Cell Malignancies

2010 ◽  
Vol 28 (21) ◽  
pp. 3525-3530 ◽  
Author(s):  
Bruce D. Cheson
Keyword(s):  
B Cell ◽  
Single Agent ◽  
Treatment Strategies ◽  
Biologic Agents ◽  
Lymphocytic Leukemia ◽  
Human Antibody ◽  
Type I ◽  
B Cell Malignancies ◽  
Anti Cd20 ◽  
Hodgkin's Lymphomas

The availability of safe and effective monoclonal antibodies (mAbs) has dramatically altered treatment strategies for B-cell malignancies. Rituximab, a type I chimeric anti-CD20 mAb, not only has activity against a broad range of CD20-positive B-cell malignancies but also, when combined with chemotherapy or other biologic agents, has improved response rates; in addition, in certain situations, progression-free survival and even overall survival may be prolonged. Recently, other anti-CD20 mAbs have been developed to improve on the activity achieved with rituximab or to demonstrate efficacy in patients whose diseases are resistant to rituximab. The most extensively studied of these is ofatumumab, a type I human antibody that binds to a different epitope of CD20 than rituximab. Preclinical data suggest improved complement-dependent cytotoxicity and antibody-dependent cellular cytotoxicity compared with rituximab. In early clinical trials, ofatumumab demonstrated single-agent activity against chronic lymphocytic leukemia (CLL) and a number of histologies of B-cell non-Hodgkin's lymphomas. This antibody was recently approved by the US Food and Drug Administration for the treatment of CLL that is resistant to both fludarabine and alemtuzumab. Additional study is ongoing with ofatumumab in combination with chemotherapy and biologic agents to further enhance its efficacy. Ofatumumab offers another effective agent with which to improve the outcome of patients with B-cell malignancies.

scholarly journals Anlotinib Shows Potent Antileukemia Effects in B-Cell Acute Lymphocytic Leukemia through the Blockage of Angiogenic Related Pathways

Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 49-49
Author(s):  
Qiuling Chen ◽  
Yuelong Jiang ◽  
Qinwei Chen ◽  
Long Liu ◽  
Bing Xu
Keyword(s):  
B Cell ◽  
Solid Tumors ◽  
Molecular Mechanisms ◽  
Conflicts Of Interest ◽  
Lymphoblastic Leukemia ◽  
Unmet Need ◽  
Lymphocytic Leukemia ◽  
Advanced Lung Cancer ◽  
Antitumor Effects

Acute lymphoblastic leukemia (ALL) derives from the malignant transformation of lymphoid progenitor cells with ~85% being originated from B-cell progenitors (B-ALL). Despite fairly good prognoses for most pediatric B-ALL patients, the outcome is fatal in over 50% of adult patients who have a recurrent or progressive disease and lack of effective therapeutic approaches. Therefore, novel treatment strategies with high efficacy and low toxicity are an unmet need for B-ALL patients, especially those with relapsed or refractory status. Angiogenesis is a process of new vessel formation that requires the participation of multiple proangiogenic factors (e.g., VEGF, PDGF, and FGF) and their corresponding receptors (e.g., VEGFR, PDGFR, and FGFR). Angiogenesis, a well-established feature of solid tumors, also contributes to leukemia progression and correlates with the involvement of specific sanctuary sites in ALL, highlighting that the perturbation of angiogenesis would be an attractive approach for ALL treatment. Anlotinib is an oral tyrosine kinase (TKI) inhibitor with a broad range of antitumor effects via the suppression of VEGFR, PDGFR and FGFR. Of importance, anlotinib has been approved for the treatment of advanced lung cancer in China. Here, we evaluated the antileukemia activity of anlotinib in preclinical B-ALL models and its underlying molecular mechanisms. In this study, we observed that anlotinib significantly blunted the capability of cell proliferation and arrested cell cycle at G2 phase in B-ALL cell lines. Subsequently, we found that anlotinib resulted in remarkably enhanced apoptosis in B-ALL in vitro. To assess the in vivo antileukemia potential, we established a B-ALL patient-derived xenograft (PDX) mouse model and then treated the B-ALL PDX model with anlotinib. As a result, oral administration of anlotinib pronouncedly delayed in vivo B-ALL cell growth and reduced leukemia burden with acceptable safety profiles in this model. As for the mechanism of action, the antileukemia effect of anlotinib was associated with the disruption of the role of VEGFR2, PDGFRb, and FGFR3. Moreover, we revealed that this drug blocked the PI3K/AKT/mTOR/ signaling, a pathway that is linked with angiogenesis and its proangiogenic regulators, including VEGFR2, PDGFRb, and FGFR3. In aggregate, these results indicate that anlotinib is a potent antitumor agent for the treatment of B-ALL via the inhibition of angiogenic relevant pathways, which provide a novel potential treatment intervention for patients with B-ALL who have little effective therapy options. Disclosures No relevant conflicts of interest to declare. OffLabel Disclosure: Anlotinib originally designed by China is a novel orally active multitarget inhibitor that is evaluating in clinical trials against multiple solid tumors.

scholarly journals Phosphoinositide 3-Kinase Signaling in the Tumor Microenvironment: What Do We Need to Consider When Treating Chronic Lymphocytic Leukemia With PI3K Inhibitors?

2021 ◽  
Vol 11 ◽  
Author(s):  
Ebru Aydin ◽  
Sebastian Faehling ◽  
Mariam Saleh ◽  
Laura Llaó Cid ◽  
Martina Seiffert ◽  
...  
Keyword(s):  
Tumor Microenvironment ◽  
Chronic Lymphocytic Leukemia ◽  
B Cell ◽  
Treatment Strategies ◽  
Cell Receptor ◽  
Pi3k Pathway ◽  
Lymphocytic Leukemia ◽  
Pi3k Signaling ◽  
Extracellular Signals ◽  
Pi3k Inhibition

Phosphoinositide 3-kinases (PI3Ks) and their downstream proteins constitute a signaling pathway that is involved in both normal cell growth and malignant transformation of cells. Under physiological conditions, PI3K signaling regulates various cellular functions such as apoptosis, survival, proliferation, and growth, depending on the extracellular signals. A deterioration of these extracellular signals caused by mutational damage in oncogenes or growth factor receptors may result in hyperactivation of this signaling cascade, which is recognized as a hallmark of cancer. Although higher activation of PI3K pathway is common in many types of cancer, it has been therapeutically targeted for the first time in chronic lymphocytic leukemia (CLL), demonstrating its significance in B-cell receptor (BCR) signaling and malignant B-cell expansion. The biological activity of the PI3K pathway is not only limited to cancer cells but is also crucial for many components of the tumor microenvironment, as PI3K signaling regulates cytokine responses, and ensures the development and function of immune cells. Therefore, the success or failure of the PI3K inhibition is strongly related to microenvironmental stimuli. In this review, we outline the impacts of PI3K inhibition on the tumor microenvironment with a specific focus on CLL. Acknowledging the effects of PI3K inhibitor-based therapies on the tumor microenvironment in CLL can serve as a rationale for improved drug development, explain treatment-associated adverse events, and suggest novel combinatory treatment strategies in CLL.

scholarly journals B-ALL Complexity: Is Targeted Therapy Still A Valuable Approach for Pediatric Patients?

Cancers ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 3498
Author(s):  
Stefano Ratti ◽  
Annalisa Lonetti ◽  
Matilde Y. Follo ◽  
Francesca Paganelli ◽  
Alberto M. Martelli ◽  
...  
Keyword(s):  
B Cell ◽  
Pediatric Patients ◽  
Hematologic Malignancy ◽  
Lymphoblastic Leukemia ◽  
Treatment Strategies ◽  
The Novel ◽  
Genomic Landscape ◽  
Cell Acute Lymphoblastic Leukemia ◽  
B Cell Precursors ◽  
Made In

B-cell acute lymphoblastic leukemia (B-ALL) is a hematologic malignancy that arises from the clonal expansion of transformed B-cell precursors and predominately affects childhood. Even though significant progresses have been made in the treatment of B-ALL, pediatric patients’ outcome has to be furtherly increased and alternative targeted treatment strategies are required for younger patients. Over the last decade, novel approaches have been used to understand the genomic landscape and the complexity of the molecular biology of pediatric B-ALL, mainly next generation sequencing, offering important insights into new B-ALL subtypes, altered pathways, and therapeutic targets that may lead to improved risk stratification and treatments. Here, we will highlight the up-to-date knowledge of the novel B-ALL subtypes in childhood, with particular emphasis on altered signaling pathways. In addition, we will discuss the targeted therapies that showed promising results for the treatment of the different B-ALL subtypes.

ZAP-70 Expression in Human B cells: Analysis of Normal Cells and Acute Lymphoblastic Leukemia (ALL) Cells with Pro/Pre B Phenotype.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 4443-4443
Author(s):  
Marta Crespo ◽  
Neus Villamor ◽  
Eva Gine ◽  
Dolors Colomer ◽  
Teresa Marafioti ◽  
...  
Keyword(s):  
B Cells ◽  
B Cell ◽  
Protein Tyrosine Kinase ◽  
Lymphoblastic Leukemia ◽  
Human Lymphocytes ◽  
Critical Role ◽  
Cell Receptor ◽  
Lymphocytic Leukemia ◽  
Qrt Pcr ◽  
Human B Cells

Abstract ZAP-70 is a protein tyrosine kinase of the Syk/ZAP-70 family that plays a critical role in the signal transduction from the T-cell receptor. In human lymphocytes, ZAP-70 gene has been reported to be expressed in T and NK derived cells, and in IgVH unmutated B-chronic lymphocytic leukemia cells. More recently, ZAP-70 expression has been shown to be required for the development of pro-B cells to pre-B cells in mice. To ascertain the expression of ZAP-70 gene in human immature B-cell stages, we analyzed ZAP-70 protein and/or mRNA in normal human B cells at different stages of B cell maturation, including pro/pre-B cells and tumoral cells from 20 B-ALL. ZAP-70 expression was assessed by flow cytometry (FC), immunofluorescence (IF), and/or by quantitative real time RT-PCR (QRT-PCR). In normal bone marrow, ZAP-70 expression was found only in T and in immature B cells (CD19+/CD10+/CD20 −). Moreover, T cells -but no mature B cells- from normal tonsil expressed ZAP-70, as assessed by QRT-PCR and IF. In B-ALLs, a high ZAP-70 expression by FC was observed in 9/13 cases (mean, 82.6%, range 60–99%), whereas in 4 cases ZAP-70 was barely detectable (mean, 13%). By QRT-PCR, 10/16 B-ALLs showed levels of expression similar to ZAP-70 non-expressing cell lines and normal B-cells, whereas in the remaining cases ZAP-70 expression was 3–4 times higher than in normal mature B-cells. Taken together, a high expression of ZAP-70 was found in 11/21 (52%) B-ALLs. No relationship was observed between the level of ZAP-70 expression and the B-ALL maturation status. In conclusion, among normal B cell subsets ZAP-70 expression is restricted to B-cells with pro/pre phenotype. In addition, ZAP-70 is expressed in 52% of B-ALLs, probably as a reflection of their B-cell origin.

B-Cell Chronic Lymphocytic Leukemia (B-CLL) Cells Unresponsive to CD180 Ligation Fail to Respond to Anti-IgM Stimulation as Well

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 3582-3582
Author(s):  
Nino Porakishvili ◽  
Peter Lydyard ◽  
Anna Bremser ◽  
Ketki Vispute ◽  
Azka Memon ◽  
...  
Keyword(s):  
B Cells ◽  
B Cell ◽  
Protein Kinases ◽  
Cell Activation ◽  
Conflicts Of Interest ◽  
Lymphocytic Leukemia ◽  
Intracellular Signalling ◽  
Orphan Receptor ◽  
B Cell Activation ◽  
Ki 67

Abstract Abstract 3582 Introduction: We have demonstrated that CD180, an orphan receptor of the Toll-like receptor family, is expressed heterogeneously on B-CLL cells, mainly on those with mutated IGVH genes. We further showed that specific ligation of CD180 with mAbs induced activation and cycling of only ~50% CD180+ B-CLL clones (“R”: responders), while CD180+ B-CLL cells unresponsive to CD180 ligation (“NR”: non-responders) or CD180− B-CLL cells could not be activated through either CD40 or IL-4 suggesting anergy. Because CD180 has a short intracellular domain, it presumably, signals through pathways associated with other receptors, such as smIgM. Indeed, engagement of smIgM or CD180 induces Lyn and Syk phosphorylation. Here we compare activation, cycling and phosphorylation of intracellular protein kinases in R and NR and CD180− B-CLL clones and B lymphocytes from healthy subjects upon ligation of smIgM. Methods: B-CLL cells were analyzed for smCD180 and smIgM, and sm CD180+IgM+ B-CLL clones were categorized as R and NR by responsiveness to CD180 ligation. Leukemic clones from 15 smCD180+IgM+R, 14 smCD180+IgM+NR, 12 smCD180−IgM+ untreated B-CLL patients and 14 healthy age-matched individuals were stimulated with goat F(ab’)2 anti-human IgM pAbs for 72h, and stained with PE~anti-CD86 mAbs, or fixed, permeabilized and stained with PE~anti-Ki-67 to assess B-cell activation and cycling, respectively. In order to study early intracellular signalling events, cells were stimulated with the same antibodies for 20 min, fixed, permeabilized and stained with Alexa Fluor~rabbit/mouse antibodies to phospho-Akt, phospho-ERK, phospho-p38MAPK, and phospho-ZAP70/Syk. Unstimulated cells in medium were used as controls. Results were assessed by flow cytometry and analyzed with the Mann-Whitney U test and paired t-test where appropriate. Results: ligation of sIgM on smCD180+IgM+R B-CLL cells resulted in a significant increase in CD86+ cells (66.3±21.7% vs 18.7±12.0%, p=0.00004) and Ki-67+ cells (38.9±10.5% vs 11.1±5.9%, p=0.0001) compared to medium controls; this was not different from the increase in activation and cycling of normal B cells (not shown). In contrast, smCD180+IgM+NR B-CLL cells failed to significantly upregulate CD86 in response to anti-IgM pAbs (20.6±13.8% vs 17.6±13.7%, p=0.334) and Ki-67 (8.4±4.6% vs 5.3±1.4%, p=0.063). Interestingly, smCD180−IgM+ B-CLL cells demonstrated diminished CD86 upregulation following sIgM ligation: 36.9±21.7% vs 11.0±4.7% in medium, p=0.058 (difference with smCD180+IgM+R B-CLL, p=0.0069). Cell cycling was also decreased: 9.7±4.1% vs 5.4±3.6% in medium, p=0.015 (difference with smCD180+IgM+R, p=0.0022). The proximal stages of anti-smIgM responses were further studied by intracellular signalling of protein kinases associated with the IgM-signalling pathway. While ligation of sIgM on control B cells and smCD180+IgM+R B-CLL cells resulted in phosphorylation of all four enzymes studied, smCD180+IgM+NR cells failed to signal downstream from ZAP70/Syk following sIgM ligation (Table 1), although there was a greater heterogeneity in smCD180+IgM+R B-CLL responses, compared to normal B cells. Importantly, smIgM ligation of smCD180−IgM+ B-CLL cells did not increase phosphorylation of Erk or p38MAPK, although some such clones responded to smIgM ligation by phosphorylation of ZAP70/Syk and Akt (data not shown). Conclusions: B-CLL clones that are smCD180+IgM+ but unresponsive to CD180 ligation (~30% of all B-CLL cases) are also unresponsive (anergic) to smIgM ligation measured by intracellular signalling, cell activation and cycling. Meanwhile, smCD180−IgM+ B-CLL clones respond heterogeneously to IgM crosslinking. Disclosures: No relevant conflicts of interest to declare.

From T-cell Engineering to CAR therapy: Progress and Prospects

Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. SCI-23-SCI-23 ◽  
Author(s):  
Michel Sadelain
Keyword(s):  
T Cells ◽  
T Cell ◽  
B Cell ◽  
Second Generation ◽  
Human Peripheral Blood ◽  
Lymphoblastic Leukemia ◽  
Stress Test ◽  
Lymphocytic Leukemia ◽  
Immunodeficient Mice ◽  
Recombinant Receptors

The genetic engineering of T cells provides a means to rapidly generate anti-tumor T cells for any cancer patient. This approach is predicated on gene transfer technology that enables the expression of receptors for antigen and other gene products in primary T cells. Tumor targeting may be achieved through the transfer of a physiological receptor for antigen, which is known as the T cell receptor (TCR), or synthetic fusion receptors, which we grouped under the general term of chimeric antigen receptor (CAR). CARs are recombinant receptors for antigen, which, in a single molecule, redirect T cell specificity and eventually enhance anti-tumor potency. Functional augmentation is achieved through the design of second generation CARs, which not only redirect cytotoxicity, but also reprogram T cell function and longevity through their costimulatory properties. The combined activating and costimulatory domains incorporated in second-generation CARs critically determine the function, differentiation, metabolism and persistence of engineered T cells. CD19 CARs that incorporate CD28 or 4-1BB signalling domains are the best known to date. Two decades ago, we selected CD19 as the prime target for developing our CAR technology and provided the first proof-of-principle that CD19-targeted human peripheral blood T cells could eradicate a broad range of B cell malignancies in immunodeficient mice (Brentjens RJ, Riviere I, et al. Eradication of systemic B-cell tumors by genetically targeted human T lymphocytes co-stimulated by CD80 and interleukin-15. 2003;9(3):279-86). CD19 has since become the poster child for CAR therapies. Complete remissions have been reported from several centers in patients with non-Hodgkin lymphoma, chronic lymphocytic leukemia and, most dramatically, acute lymphoblastic leukemia. Two types of second generation CARs, utilizing either CD28 or 4-1BB as their costimulatory signaling components, have been used in ALL patients. Both have yielded dramatic outcomes, in adults as well as in children. Our data indicate that CD28-based CARs direct a brisk proliferative response and boost effector functions, while 4-1BB-based CARs direct a gradual T cell accumulation that may eventually overcome lesser functional potency. These distinct kinetic features can be exploited to further develop CAR T cell therapies for a variety of cancers. We have now modeled CD19 CAR therapy for ALL in a "stress test", wherein we purposefully lower the infused T cell doses to challenge the CAR therapy. We have compared novel CAR designs intended to recruit both CD28 and 4-1BB signaling. These quantitative analyses reveal striking disparities that hinge on subtle variations in the structural design of CARs and co-expressed costimulatory molecules. Remarkably, we find that some of the most effective engineering strategies activate and sustain the recruitment of the IFNβ pathway through the induction of IRF7, while lowering the induction of exhaustion markers relative to second generation CARs activating either CD28 or 4-1BB alone. The field is thus poised to move beyond the CD28 vs 4-1BB debate, which will be rendered obsolete by the emergence of superior CAR designs that coopt the use of costimulatory ligands, cytokines and/or checkpoint blockade inhibitors. A new field of immunopharmacology is emerging. Disclosures Sadelain: Juno Therapeutics: Consultancy, Equity Ownership, Other: Co-Founder, stockholder, Patents & Royalties: Licensed patents on CARs.

scholarly journals ROR1 targeting with the antibody drug-conjugate VLS-101 is effective in Richter syndrome patient-derived xenograft mouse models

Blood ◽  
2021 ◽  
Author(s):  
Tiziana Vaisitti ◽  
Francesca Arruga ◽  
Nicoletta Vitale ◽  
Thanh-Trang Thi Lee ◽  
Mira Ko ◽  
...  
Keyword(s):  
Therapeutic Potential ◽  
Lymphocytic Leukemia ◽  
Orphan Receptor ◽  
Aggressive Lymphoma ◽  
Tumor Cell Death ◽  
Antibody Drug Conjugate ◽  
Drug Conjugate ◽  
Richter Syndrome ◽  
Hematological Cancers ◽  
Antibody Drug

Richter syndrome (RS) represents the transformation of chronic lymphocytic leukemia (CLL), typically to an aggressive lymphoma. Treatment options for RS are limited and the disease is often fatal. Receptor tyrosine kinase-like orphan receptor 1 (ROR1) is expressed on CLL cells and other cancers but not on normal adult tissues, making it an attractive, tumor-specific therapeutic target. VLS‑101 is being developed as an antibody-drug conjugate (ADC) for therapy of ROR1-expressing (ROR1+) cancers. VLS-101 comprises UC‑961 (a humanized immunoglobulin IgG1 monoclonal antibody that binds an extracellular epitope of human ROR1), a maleimidocaproyl-valine-citrulline-para-aminobenzoate (mc-vc-PAB) linker, and the anti‑microtubule cytotoxin monomethyl auristatin E (MMAE). VLS‑101 binding to ROR1 results in rapid cellular internalization and delivery of MMAE to induce tumor cell death. We studied 4 RS patient-derived xenografts (RS‑PDXs) with varying levels of ROR1 expression (11%, 32%, 85%, 99% of cells). VLS-101 showed no efficacy in the lowest-expressing RS-PDX but induced complete remissions in those with higher levels of ROR1 expression. Responses were maintained during the post-therapy period, particularly after higher VLS-101 doses. In systemic ROR1+ RS-PDXs, VLS-101 dramatically decreased tumor burden in all RS-colonized tissues and significantly prolonged survival. Animals showed no adverse effects or weight loss. Our results confirm ROR1 as a target in RS and demonstrate the therapeutic potential of using an ADC directed toward ROR1 for the treatment of hematological cancers. A Phase 1 clinical trial of VLS‑101 (NCT03833180) is ongoing in patients with RS and other hematological malignancies.

scholarly journals Constitutive expression of the interleukin-6 gene in chronic lymphocytic leukemia

Blood ◽  
1989 ◽  
Vol 73 (5) ◽  
pp. 1279-1284
Author(s):  
A Biondi ◽  
V Rossi ◽  
R Bassan ◽  
T Barbui ◽  
S Bettoni ◽  
...  
Keyword(s):  
Gene Expression ◽  
Chronic Lymphocytic Leukemia ◽  
B Cell ◽  
Interleukin 6 ◽  
Lymphoblastic Leukemia ◽  
Cdna Probe ◽  
Constitutive Expression ◽  
Lymphocytic Leukemia ◽  
Biologically Active ◽  
Stimulatory Factor

Interleukin-6 (IL-6) is a pleiotropic lymphokine active as a growth factor on B-cell hybridomas and plasmacytomas and found to be identical with B-cell stimulatory factor 2, interferon beta 2, 26-Kd protein, and hepatocytes stimulating factor. IL-6 gene expression was investigated in fresh human chronic lymphocytic leukemia (B-CLL) and in acute lymphoblastic leukemia (ALL) by Northern blot analysis using a specific cDNA probe. 1.3-kb IL-6 transcript was found in six out of 11 B-CLL patients, while no hybridization was observed in ten cases of ALL of both T- and B-cell origin. The constitutive expression of IL-6 transcripts was associated with production of a biologically active protein as determined by using the IL-6-dependent 7TD1 cell line. It remains to be elucidated whether IL-6 gene expression is indeed important in the regulation of B-CLL growth or in its clinical manifestation.

scholarly journals Overcoming resistance to targeted therapies in chronic lymphocytic leukemia

2021 ◽  
Vol 5 (1) ◽  
pp. 334-343
Author(s):  
Sigrid S. Skånland ◽  
Anthony R. Mato
Keyword(s):  
Chronic Lymphocytic Leukemia ◽  
B Cell ◽  
Targeted Therapies ◽  
Rational Design ◽  
Treatment Options ◽  
Critical Role ◽  
Acquired Resistance ◽  
B Cell Lymphoma ◽  
Lymphocytic Leukemia ◽  
T Cell Therapy

Abstract Insight into the critical role of B-cell receptor signaling for the pathogenesis of chronic lymphocytic leukemia (CLL) led to the development of targeted therapies directed at key regulators of cell survival. Agents targeting B-cell lymphoma-2 protein, Bruton’s tyrosine kinase (BTK), and phosphatidylinositol 3-kinase are approved for treatment of CLL, and have significantly improved the disease management. Nevertheless, acquired resistance to the targeted therapies is a challenge still to be resolved. The mechanisms underlying resistance are becoming clearer, and include secondary mutations within the drug target and activation of bypass pathways. This knowledge has allowed development of strategies to prevent and overcome treatment resistance. Approaches to prevent resistance include targeting bypass mechanisms by combination therapies, temporally sequencing of therapies, improved clinical trial designs, and real-time monitoring of patient response. A rational design of drug sequencing may secure effective treatment options at the relapsed setting. Next-generation inhibitors and bispecific antibodies have the potential to overcome resistance to the BTK inhibitor ibrutinib. Immunotherapy, including chimeric antigen receptor-modified T-cell therapy, is explored for relapsed CLL. Here, recent advances that have contributed to the understanding of resistance to targeted therapies in CLL are discussed. Strategies for managing resistance are reviewed, including translational, real-world, and clinical perspectives.

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