acp-196 and Lymphoma--B-Cell

B cell receptor (BCR) signaling plays a key role in B cell development and function. Aberrant BCR signaling has been confirmed as a central driver for the pathogenesis of various B cell malignancies. Bruton's tyrosine kinase (BTK) is a vital component of BCR signaling and exhibits overexpression in various B cell leukemias and lymphomas. Inhibiting BTK has been proved as an efficient way for B cell malignancy intervention. Remarkable achievements have been made in the pursuit of selective BTK inhibitors, represented by the success of the irreversible BTK inhibitors, ibrutinib and acalabrutinib. Constantly emerging agents exhibiting superior efficacy and safety in preclinical and clinical studies provide promising therapeutics for the treatment of B cell malignancies.

Topics: Adenine; Agammaglobulinaemia Tyrosine Kinase; Animals; Antineoplastic Agents; Autoimmune Diseases; Benzamides; Drug Design; Humans; Leukemia, B-Cell; Lymphoma, B-Cell; Piperidines; Protein Kinase Inhibitors; Protein-Tyrosine Kinases; Pyrazines; Pyrazoles; Pyrimidines

Bruton's tyrosine kinase (BTK) is crucial in B-cell development and survival. The role of BTK as a downstream kinase in the B-cell receptor (BCR) signaling pathway is well described. As a key player in the pathogenesis of B-cell malignancies, targeting of dysregulated BCR signaling has been explored by development of inhibitors of downstream mediators. Discovery of the biological function of BTK and the development of covalent inhibitors for clinical use, ibrutinib as the lead agent and acalabrutinib as the second clinically approved BTK inhibitor, have revolutionized the treatment options for B-cell malignancies. Currently, ibrutinib is approved for mantle cell lymphoma, chronic lymphocytic leukemia, lymphoplasmacytic lymphoma/Waldenström macroglobulinemia, small lymphocytic lymphoma, marginal zone lymphoma and chronic graft versus host disease, while acalabrutinib is approved for mantle cell lymphoma. Potential expansion of indications in other diseases is under investigation in several clinical trials, while combination of BTK inhibitors with either chemoimmunotherapy or other targeted agents is being systematically explored in B-cell malignancies.

Topics: Adenine; Agammaglobulinaemia Tyrosine Kinase; Antineoplastic Agents; B-Lymphocytes; Benzamides; Drug Therapy, Combination; Humans; Lymphoma, B-Cell; Lymphoma, Mantle-Cell; Molecular Targeted Therapy; Piperidines; Protein Kinase Inhibitors; Pyrazines; Pyrazoles; Pyrimidines

Topics: Adenosine; Benzamides; Humans; Lymphoma, B-Cell; Phosphatidylinositol 3-Kinases; Pyrazines; Quinolines

Bruton's tyrosine kinase (Btk) is a crucial signaling molecule in BCR signaling and a key regulator of B- cell differentiation and function. Btk inhibition has shown impressive clinical efficacy in various B-cell malignancies. However, it remains unknown whether inhibition additionally induces changes in BCR signaling due to feedback mechanisms, a phenomenon referred to as BCR rewiring. In this report, we studied the impact of Btk activity on major components of the BCR signaling pathway in mice. As expected, NF-κB and Akt/S6 signaling was decreased in Btk-deficient B cells. Unexpectedly, phosphorylation of several proximal signaling molecules, including CD79a, Syk, and PI3K, as well as the key Btk-effector PLCγ2 and the more downstream kinase Erk, were significantly increased. This pattern of BCR rewiring was essentially opposite in B cells from transgenic mice overexpressing Btk. Importantly, prolonged Btk inhibitor treatment of WT mice or mice engrafted with leukemic B cells also resulted in increased phosho-CD79a and phospho-PLCγ2 in B cells. Our findings show that Btk enzymatic function determines phosphorylation of proximal and distal BCR signaling molecules in B cells. We conclude that Btk inhibitor treatment results in rewiring of BCR signaling, which may affect both malignant and healthy B cells.

Topics: Agammaglobulinaemia Tyrosine Kinase; Animals; Antineoplastic Agents; B-Lymphocytes; Benzamides; CD79 Antigens; Extracellular Signal-Regulated MAP Kinases; Immunoglobulin M; Lymphoma, B-Cell; Mice; Mice, Inbred C57BL; Mice, Knockout; NF-kappa B; Phosphatidylinositol 3-Kinases; Phospholipase C gamma; Phosphorylation; Proto-Oncogene Proteins c-akt; Pyrazines; Receptors, Antigen, B-Cell; Signal Transduction; Syk Kinase

As the SARS-CoV-2 (COVID-19) pandemic spreads and the number of Bruton's tyrosine kinase inhibitor (BTKi)-treated COVID-19-affected patients grows, we must consider the pros and cons of BTKi discontinuation for our patients. In favor of BTKi continuation, BTK plays an active role in macrophage polarization. By modulating key transcription factors, BTK may regulate macrophage polarization downstream of classic M1 and M2 polarizing stimuli and mitigate the hyperinflammatory state associated with COVID-19. In favor of BTKi discontinuation, we note a potentially increased risk of secondary infections and impaired humoral immunity. We hypothesize that the potential benefit of blunting a hyperinflammatory response to SARS-CoV-2 through attenuation of M1 polarization outweighs the potential risk of impaired humoral immunity, not to mention the risk of rapid progression of B-cell malignancy following BTKi interruption. On the basis of this, we suggest continuing BTKi in patients with COVID-19.

Topics: Adenine; Agammaglobulinaemia Tyrosine Kinase; Anti-Inflammatory Agents; Antineoplastic Agents; Benzamides; Betacoronavirus; Coronavirus Infections; COVID-19; Humans; Inflammation; Leukemia, Lymphocytic, Chronic, B-Cell; Lymphoma, B-Cell; Macrophages; Pandemics; Piperidines; Pneumonia, Viral; Protein Kinase Inhibitors; Pyrazines; Pyrazoles; Pyrimidines; SARS-CoV-2

The B-cell receptor and the phosphatidylinositol 3-kinase (PI3K) signalling pathways, together with their downstream partners, represent important therapeutic targets for B-cell lymphomas. Here, we evaluated the activity of acalabrutinib (ACP-196) and ACP-319 (AMG-319), second generation inhibitors of Bruton tyrosine kinase (BTK) and PI3Kδ inhibitor, respectively, in lymphoma pre-clinical models. The two compounds showed activity in activated B-cell-like diffuse large B-cell lymphoma (ABC DLBCL), mantle cell lymphoma and marginal zone lymphoma. Two in vivo experiments with ABC DLBCL and MCL xenografts confirmed the effect of the single agents. Benefit was achieved by exposing the lymphoma cell lines to both acalabrutinib and ACP-319. Two cell lines presented a discordant response to first and second generation BTK inhibitors, probably due to the inhibition by ibrutinib of kinases other than BTK. In conclusion, our data sustain the on-going current trials with acalabrutinib and ACP-319 as single agents and provide the basis for the investigation of their combination as well.

Topics: Adenosine; Agammaglobulinaemia Tyrosine Kinase; Animals; Antineoplastic Combined Chemotherapy Protocols; Benzamides; Cell Proliferation; Class I Phosphatidylinositol 3-Kinases; Drug Synergism; Humans; Lymphoma, B-Cell; Lymphoma, B-Cell, Marginal Zone; Lymphoma, Large B-Cell, Diffuse; Lymphoma, Mantle-Cell; Mice, SCID; Protein Kinase Inhibitors; Pyrazines; Quinolines; Tumor Cells, Cultured; Xenograft Model Antitumor Assays