A novel inhibitor of focal adhesion signaling induces caspase-independent cell death in diffuse large B-cell lymphoma

Abstract

Focal adhesion (FA) proteins have been associated with transformation, migration, metastasis, and poor outcome in many neoplasias. We previously showed that these proteins were inhibited by E7123, a new celecoxib derivative with antitumor activity, in acute myeloid leukemia. However, little is known about FAs in diffuse large B cell lymphoma (DLBCL). This paper aimed to determine whether E7123 was effective against DLBCL and whether FAs were involved in its action.We evaluated the cytotoxicity and mechanism of action of E7123 and celecoxib in DLBCL cell lines. We also assessed the E7123 in vivo activity in a DLBCL xenograft model and studied FA signaling in primary DLBCL patient samples. We found that E7123 showed higher antitumor effect than celecoxib against DLBCL cells. Its mechanism of action involved deregulation of FA, AKT, and Mcl-1 proteins, a pathway that is activated in some patient samples, apoptosis-inducing factor release and induction of caspase-independent cell death. Moreover, E7123 showed suppression of in vivo tumor growth. These findings indicate that E7123 is effective against DLBCL in vitro and in vivo, with a mechanism of action that differs from that of most current therapies for this malignancy. IntroductionDiffuse large B-cell lymphoma (DLBCL) is the most frequent non-Hodgkin lymphoma subtype. Cure rates have increased in recent years with the addition of rituximab to the combination chemotherapy: cyclophosphamide, doxorubicin, vincristine, and prednisone. 1 However, a significant percentage of patients still relapse because lymphoma cells acquire resistance to therapy, which is associated with defective caspase-dependent apoptotic pathways. [2][3][4] Paradoxically, almost all cytotoxic drugs currently in clinical use for DLBCL induce caspase-dependent apoptosis. 5 Thus, the development of novel compounds with mechanisms of action able to induce caspase-independent cell death probably improves the therapeutic outcome in DLBCL, particularly in patients who relapse after front-line therapy.Focal adhesion (FA) complexes are structures that link the actin filaments of the cytoskeleton with the extracellular matrix. They are formed by transmembrane receptors (integrins) that activate various protein kinases, including the focal adhesion kinase (FAK) and Src family kinases. 6 Crk-associated substrate (CAS) family proteins act as docking proteins that associate with FAK and Src to generate specific cellular responses. 7 FA proteins have been related to transformation, 8 migration, 9 metastasis, 10 and poor outcome 11 in many solid tumors and in some hematologic malignancies. 12,13 However, there are limited data regarding the role of FA proteins in DLBCL. To our knowledge, only FAK and the Src-family protein LYN have been studied in DLBCL. FAK is expressed in 70% of DLBCLs 14 and LYN is constitutively phosphorylated and required for DLBCL growth, survival, and proliferation. 15,16 Other FA proteins, such as HEF1 or p130Cas from the CAS family, or PYK2 from the FAK family, play crucial roles ...

Subcutaneous passage increases cell aggressiveness in a xenograft model of diffuse large B cell lymphoma

“…The AKT pathway is highly relevant in DLBCL since 72% of patients show its activation [28]. We have recently published that FAK and p130Cas are also expressed in the majority of human DLBCL patient samples [29] but their role in this malignancy is still unknown. However, increased FAK and/or p130Cas expression and activity have been frequently correlated with malignant or metastatic disease and poor patient prognosis.…”

The copper chelator ATN-224 induces caspase-independent cell death in diffuse large B cell lymphoma

“…The upregulation of anti-apoptotic proteins results in defective caspase-dependent apoptotic pathways. Many of the cytotoxic drugs used to treat DLBCL induce caspase-dependent apoptosis (3). The ability of ATN-224 to induce cell death via the release of AIF from the mitochondria suggests that patients with tumors that have defective caspase-dependent pathways could benefit from ATN-224 treatment.…”

“…While cure rates have increased, the lack of response to current standard treatment and/or relapse leaves approximately 50% of patients incurable (1,2). Many of the cytotoxic drugs used to treat DLBCL induce caspase-dependent apoptosis, however, a significant number of patients acquire resistance that is associated with defective caspase-dependent apoptotic pathways (3). Upregulation of the BCL2 gene, due to either the t(14;18) translocation or genomic BCL2 gain/amplification, results in overexpression of the Bcl-2 protein and apoptosis resistance (2).…”

Effect of serpinE1 overexpression on the primary tumor and lymph node, and lung metastases in head and neck squamous cell carcinoma

“…74BGFPLuc and 74BserpE1up cell lines were cultured in Dulbecco's Modified Eagle's Medium (DMEM) containing 10% Fetal Bovine Serum (FBS), 100 U/mL streptomycin/penicillin and 2 mM glutamine (Thermo Fisher Scientific, Waltham, Massachusetts) and maintained in a humidified atmosphere at 37°C and 5% CO 2 . 74BserpE1up and 74BGFPLuc cell lines stably expressing GFP and Luciferase were obtained by lentiviral transduction with pSIN‐DUAL‐Luc‐GP2 vector, as described previously …”