Targeting PYK2 mediates microenvironment-specific cell death in multiple myeloma

Abstract

Multiple myeloma (MM) remains an incurable malignancy due, in part, to the influence of the bone marrow microenvironment on survival and drug response. Identification of microenvironment-specific survival signaling determinants is critical for the rational design of therapy and elimination of MM. Previously, we have shown that collaborative signaling between β1 integrin-mediated adhesion to fibronectin and interleukin-6 confers a more malignant phenotype via amplification of signal transducer and activator of transcription 3 (STAT3) activation. Further characterization of the events modulated under these conditions with quantitative phosphotyrosine profiling identified 193 differentially phosphorylated peptides. Seventy-seven phosphorylations were upregulated upon adhesion, including PYK2/FAK2, Paxillin, CASL and p130CAS consistent with focal adhesion (FA) formation. We hypothesized that the collaborative signaling between β1 integrin and gp130 (IL-6 beta receptor, IL-6 signal transducer) was mediated by FA formation and proline-rich tyrosine kinase 2 (PYK2) activity. Both pharmacological and molecular targeting of PYK2 attenuated the amplification of STAT3 phosphorylation under co-stimulatory conditions. Co-culture of MM cells with patient bone marrow stromal cells (BMSC) showed similar β1 integrin-specific enhancement of PYK2 and STAT3 signaling. Molecular and pharmacological targeting of PYK2 specifically induced cell death and reduced clonogenic growth in BMSC-adherent myeloma cell lines, aldehyde dehydrogenase-positive MM cancer stem cells and patient specimens. Finally, PYK2 inhibition similarly attenuated MM progression in vivo. These data identify a novel PYK2-mediated survival pathway in MM cells and MM cancer stem cells within the context of microenvironmental cues, providing preclinical support for the use of the clinical stage FAK/PYK2 inhibitors for treatment of MM, especially in a minimal residual disease setting.

Anthelmintic pyrvinium pamoate blocks Wnt/β-catenin and induces apoptosis in multiple myeloma cells

“…The progression of MM involves primary cytogenetic abnormalities (cyclin D, fibroblast growth factor receptor 3, histone-lysine N-methyltransferase, or musculoaponeurotic fibrosarcoma) in myeloma-initiating cells. The oncogenic growth of MM cells is hypothesized to be supported by intracellular oncogenic events and tumor microenvironment components, such as bone marrow stromal cells (4)(5)(6).…”

Standardisation of minimal residual disease in multiple myeloma

“…Jakubowiak and his group, using Carfilzomib in combination with lenalidomide and low-dose dexamethasone, in MM, achieved sCR rate of 42%, a result never before reached (Jakubowiak et al, 2012). It has been shown that disease progression or relapse are primarily due to residual myeloma reservoirs through environmentmediated drug resistance and/or the persistence of myeloma stem cells Allegra, Alonci, Penna, et al, 2014;Meads et al, 2016;Shain & Dalton, 2009;.…”

Targeting Intrinsic and Extrinsic Vulnerabilities for the Treatment of Multiple Myeloma

“…Recent studies indicate that interaction between β1 integrin, fibronectin, and interleukin‐6 in bone marrow microenvironment results in increased activation of Pyk2, resulting in amplification of signal transducer and activator of transcription 3 (STAT3) activation. Molecular and pharmacological targeting of Pyk2 results in attenuated MM progression in vivo [Meads et al, ]. Interestingly, the dependency of Pyk2 in mediating survival in these studies was more notable when MM cells were placed in co‐culture with bone marrow stroma cells compared to unicellular MM model.…”