Carmela Gurrieri

Towards a new age in the treatment of multiple myeloma

Multiple myeloma (MM) is an incurable disease characterized by the proliferation of end-stage B lymphocytes (plasma cells, PCs). As a consequence of myeloma growth in the bone marrow, a number of signaling pathways are activated that trigger malignant PC proliferation, escape from apoptosis, migration, and invasion. Thanks to new insights into the molecular pathogenesis of MM, novel approaches aimed at targeting these abnormally activated cascades have recently been developed and others are under study. These strategies include the inhibition of membrane receptor tyrosine kinases, inhibition of the proteasome/aggresome machinery, inhibition of histone deacetylases, inhibition of farnesyltransferases, targeting of molecular chaperones, and others. We will herein review and discuss these novel biological approaches with particular emphasis on those based on biochemical pathways which drive cell signaling. By providing the rationale for innovative therapeutic strategies, the above mechanisms represent targets for new compounds being tested in the management of this disease.

Protein Kinase CK2 Inhibition Down Modulates the NF-κB and STAT3 Survival Pathways, Enhances the Cellular Proteotoxic Stress and Synergistically Boosts the Cytotoxic Effect of Bortezomib on Multiple Myeloma and Mantle Cell Lymphoma Cells

CK2 is a pivotal pro-survival protein kinase in multiple myeloma that may likely impinge on bortezomib-regulated cellular pathways. In the present study, we investigated CK2 expression in multiple myeloma and mantle cell lymphoma, two bortezomib-responsive B cell tumors, as well as its involvement in bortezomib-induced cytotoxicity and signaling cascades potentially mediating bortezomib resistance. In both tumors, CK2 expression correlated with that of its activated targets NF-κB and STAT3 transcription factors. Bortezomib-induced proliferation arrest and apoptosis were significantly amplified by the simultaneous inhibition of CK2 with two inhibitors (CX-4945 and K27) in multiple myeloma and mantle cell lymphoma cell lines, in a model of multiple myeloma bone marrow microenvironment and in cells isolated from patients. CK2 inhibition empowered bortezomib-triggered mitochondrial-dependent cell death. Phosphorylation of NF-κB p65 on Ser529 (a CK2 target site) and rise of the levels of the endoplasmic reticulum stress kinase/endoribonuclease Ire1α were markedly reduced upon CK2 inhibition, as were STAT3 phospho Ser727 levels. On the contrary, CK2 inhibition increased phospho Ser51 eIF2α levels and enhanced the bortezomib-dependent accumulation of poly-ubiquitylated proteins and of the proteotoxic stress-associated chaperone Hsp70. Our data suggest that CK2 over expression in multiple myeloma and mantle cell lymphoma cells might sustain survival signaling cascades and can antagonize bortezomib-induced apoptosis at different levels. CK2 inhibitors could be useful in bortezomib-based combination therapies.

Glycogen Synthase Kinase-3 regulates multiple myeloma cell growth and bortezomib-induced cell death

BackgroundGlycogen Synthase Kinase-3 (GSK-3) α and β are two serine-threonine kinases controlling insulin, Wnt/β-catenin, NF-κB signaling and other cancer-associated transduction pathways. Recent evidence suggests that GSK-3 could function as growth-promoting kinases, especially in malignant cells. In this study, we have investigated GSK-3α and GSK-3β function in multiple myeloma (MM).MethodsGSK-3 α and β expression and cellular localization were investigated by Western blot (WB) and immunofluorescence analysis in a panel of MM cell lines and in freshly isolated plasma cells from patients. MM cell growth, viability and sensitivity to bortezomib was assessed upon treatment with GSK-3 specific inhibitors or transfection with siRNAs against GSK-3 α and β isoforms. Survival signaling pathways were studied with WB analysis.ResultsGSK-3α and GSK-3β were differently expressed and phosphorylated in MM cells. Inhibition of GSK-3 with the ATP-competitive, small chemical compounds SB216763 and SB415286 caused MM cell growth arrest and apoptosis through the activation of the intrinsic pathway. Importantly, the two inhibitors augmented the bortezomib-induced MM cell cytotoxicity. RNA interference experiments showed that the two GSK-3 isoforms have distinct roles: GSK-3β knock down decreased MM cell viability, while GSK-3α knock down was associated with a higher rate of bortezomib-induced cytotoxicity. GSK-3 inhibition caused accumulation of β-catenin and nuclear phospho-ERK1, 2. Moreover, GSK-3 inhibition and GSK-3α knockdown enhanced bortezomib-induced AKT and MCL-1 protein degradation. Interestingly, bortezomib caused a reduction of GSK-3 serine phosphorylation and its nuclear accumulation with a mechanism that resulted partly dependent on GSK-3 itself.ConclusionsThese data suggest that in MM cells GSK-3α and β i) play distinct roles in cell survival and ii) modulate the sensitivity to proteasome inhibitors.

Inhibition of protein kinase CK2 with the clinical- grade small ATP-competitive compound CX-4945 or by RNA interference unveils its role in acute myeloid leukemia cell survival, p53-dependent apoptosis and daunorubicin-induced cytotoxicity

BackgroundThe involvement of protein kinase CK2 in sustaining cancer cell survival could have implications also in the resistance to conventional and unconventional therapies. Moreover, CK2 role in blood tumors is rapidly emerging and this kinase has been recognized as a potential therapeutic target. Phase I clinical trials with the oral small ATP-competitive CK2 inhibitor CX-4945 are currently ongoing in solid tumors and multiple myeloma.MethodsWe have analyzed the expression of CK2 in acute myeloid leukemia and its function in cell growth and in the response to the chemotherapeutic agent daunorubicin We employed acute myeloid leukemia cell lines and primary blasts from patients grouped according to the European LeukemiaNet risk classification. Cell survival, apoptosis and sensitivity to daunorubicin were assessed by different means. p53-dependent CK2-inhibition-induced apoptosis was investigated in p53 wild-type and mutant cells.ResultsCK2α was found highly expressed in the majority of samples across the different acute myeloid leukemia prognostic subgroups as compared to normal CD34+ hematopoietic and bone marrow cells. Inhibition of CK2 with CX-4945, K27 or siRNAs caused a p53-dependent acute myeloid leukemia cell apoptosis. CK2 inhibition was associated with a synergistic increase of the cytotoxic effects of daunorubicin. Baseline and daunorubicin-induced STAT3 activation was hampered upon CK2 blockade.ConclusionsThese results suggest that CK2 is over expressed across the different acute myeloid leukemia subsets and acts as an important regulator of acute myeloid leukemia cell survival. CK2 negative regulation of the protein levels of tumor suppressor p53 and activation of the STAT3 anti-apoptotic pathway might antagonize apoptosis and could be involved in acute myeloid leukemia cell resistance to daunorubicin.

Protein kinase CK2 regulates AKT, NF-κB and STAT3 activation, stem cell viability and proliferation in acute myeloid leukemia

Protein kinase CK2 sustains acute myeloid leukemia cell growth, but its role in leukemia stem cells is largely unknown. Here, we discovered that the CK2 catalytic α and regulatory β subunits are consistently expressed in leukemia stem cells isolated from acute myeloid leukemia patients and cell lines. CK2 inactivation with the selective inhibitor CX-4945 or RNA interference induced an accumulation of leukemia stem cells in the late S–G2–M phases of the cell cycle and triggered late-onset apoptosis. As a result, leukemia stem cells displayed an increased sensitivity to the chemotherapeutic agent doxorubicin. From a molecular standpoint, CK2 blockade was associated with a downmodulation of the stem cell-regulating protein BMI-1 and a marked impairment of AKT, nuclear factor-κB (NF-κB) and signal transducer and activator of transcription 3 (STAT3) activation, whereas FOXO3a nuclear activity was induced. Notably, combined CK2 and either NF-κB or STAT3 inhibition resulted in a superior cytotoxic effect on leukemia stem cells. This study suggests that CK2 blockade could be a rational approach to minimize the persistence of residual leukemia cells.

Bone marrow stromal cell-fueled multiple myeloma growth and osteoclastogenesis are sustained by protein kinase CK2

Bone marrow stromal cell-fueled multiple myeloma growth and osteoclastogenesis are sustained by protein kinase CK2

Epidemiology and risk factors of invasive fungal infections in a large cohort of patients with chronic lymphocytic leukemia.

Invasive fungal infections (IFI) are serious, life‐threatening complications of hematological malignancies particularly in patients affected by acute myeloid leukemia and following hematopoietic stem cell transplantation. Although data on IFI in patients with acute leukemia have been updated in the past years, little information is available in patients with lymphoproliferative malignancies, particularly in chronic lymphocytic leukemia (CLL). Chronic lymphocytic leukemia is the most common leukemia in western country with an estimated incidence of 4 to 5 cases per 100 000 people per year and is characterized by a variable clinical course. Although new therapies are available to manage the leukemic process, infections are the major cause of morbidity and mortality contributing to 25% to 50% of deaths. Susceptibility to infections in CLL patients can be related to immunological defects associated with the disease (including hypogammaglobulinemia, T cell, natural killer cell, and innate immunity abnormalities) and secondary to chemoimmunotherapy. Hypogammaglobulinemia and T‐cell defects are quite common at diagnosis and become more pronounced with advanced‐stage disease. Interestingly, it has been reported that even patients with monoclonal B‐cell lymphocytosis harbor a higher risk of serious infection than the general population. Strategies to prevent bacterial infections in patients with symptomatic hypogammaglobulinemia include prophylactic antibiotics or immunoglobulin replacement therapy (IgRT). Although passive immunotherapy with immunoglobulin (IG) allows a reduction of minor and major bacterial infections, several data suggest that IgRT does not result in a decrease of mortality, and to date, no clear indications for this treatment are available. In this work, we aimed to identify the clinical and biological features of CLL patients who developed IFI. We retrospectively reviewed data from 795 subjects with CLL referred to our unit from 1983 to 2015. Invasive fungal infections were defined as infective events caused by yeast or mould that required inpatient management and/ or intravenous antifungal therapies. In this study, we included only proven and probable IFI, according to international guidelines. Time to IFI and overall survival were calculated from the date of CLL diagnosis to IFI development or death (event), respectively, or last available follow‐up (censored). Diagnostic work‐up of fungal infection included blood cultures collection, serum galactomannan (GM) antigen test for 3 consecutive

Major infections, secondary cancers and autoimmune diseases occur in different clinical subsets of chronic lymphocytic leukaemia patients

BACKGROUNDnMajor infections (MIs), secondary cancers (SCs) and autoimmune diseases (ADs) are the most common and relevant complications in patients with chronic lymphocytic leukaemia.nnnMETHODSnWe performed a single-centre retrospective study to investigate the prevalence of the above quoted complications, the association with most important prognostic markers and their impact on survival (nxa0=xa0795).nnnRESULTSnAlmost one out of three patients experienced at least one complication and only 0.9% of the cohort developed all three complications. One hundred and twenty (20%) subjects developed SC, 98 MI (12%) and 80 AD (10%); these complications seem to occur in a mutually exclusive manner. By Kaplan-Meier analysis we estimated that after 20 years from the diagnosis SC, MI and AD occurred in 48%, 42% and 29% of patients, respectively. Furthermore, we showed that some clinical and biological markers are skewed among patients with different complications and that subjects with MI and SC had a worse prognosis than those with AD and all other patients (pxa0<xa00.0001).nnnCONCLUSIONSnThis study reveals the existence of different clinical subsets of chronic lymphocytic leukaemia patients characterised by an increased and different risk for developing specifically MI, SC and AD.

Complex chromosomal rearrangements leading to MECOM overexpression are recurrent in myeloid malignancies with various 3q abnormalities.

Chromosomal rearrangements involving 3q26 are recurrent findings in myeloid malignancies leading to MECOM overexpression, which has been associated with a very poor prognosis. Other 3q abnormalities have been reported and cryptic MECOM rearrangements have been identified in some cases. By fluorescence in situ hybridization (FISH) analysis, we investigated 97 acute myeloid leukemia/myelodysplastic syndrome patients with various 3q abnormalities to determine the role and the frequency of the involvement of MECOM. We identified MECOM rearrangements in 51 patients, most of them showed 3q26 involvement by chromosome banding analysis (CBA): inv(3)/t(3;3) (nu2009=u200926) and other balanced 3q26 translocations (t(3q26)) (nu2009=u200915); the remaining cases (nu2009=u200910) showed various 3q abnormalities: five with balanced translocations involving 3q21 or 3q25; two with homogenously staining region (hsr) on 3q; and three with other various 3q abnormalities. Complex rearrangements with multiple breakpoints on 3q, masking 3q26 involvement, were identified in cases with 3q21/3q25 translocations. Furthermore, multiple breaks were observed in two cases with t(3q26), suggesting that complex rearrangement may also occur in apparently simple t(3q26). Intrachromosomal gene amplification was another mechanism leading to MECOM overexpression in two cases with hsr on 3q. In the last three cases, FISH analysis revealed 3q26 involvement that was missed by CBA because of metaphases suboptimal quality. All cases with MECOM rearrangements showed overexpression by real‐time quantitative PCR. Finally, MECOM rearrangements can occur in patients with 3q abnormalities even in the absence of specific 3q26 involvement, underlining that their frequency is underestimated. As MECOM rearrangement has been associated with very poor prognosis, its screening should be performed in patients with any 3q abnormalities.