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Background: WM is an incurable low-grade lymphoplasmacytic lymphoma with limited options of therapy. Proteasome inhibition has been shown to induce components of the proapoptotic/terminal unfolded protein response (UPR), a signaling pathway activated by accumulation of misfolded proteins within the endoplasmic reticulum (ER). We previously found that UPR gene expression is related to disease activity in WM with a particular role for GRP78/Bip as a prognostic factor. We therefore examined tunicamycin (Sigma, St Louis, MO), a potent inducer of ER stress, for potential anti-tumor effects in WM. Methods: WM cell lines (BCWM.1 and WSU-WM), IgM secreting low-grade lymphoma cell lines (MEC1, RL) and primary CD19+ selected LPC cells from WM patients were incubated with tunicamycin (0.01–10 uM) for 24–72 hours and evaluated by MTT, thymidine uptake, and Apo2.7/PI staining for effects on proliferation and survival. Since bone marrow stromal cells (BMSC) confer growth and resistance to conventional treatments, we also tested the effect of tunicamycin on WM cells co-cultured with BMSC. Immunoblotting for caspases was also performed and expression of UPR genes determined using relative quantitative RT-PCR reaction following (0.5–16 hrs) culture with tunicamycin. Results: WM cells inherently expressed the ER chaperones GRP78/Bip and GRP94/gp96. Tunicamycin rapidly induced components of the proapoptotic/terminal UPR, including PERK, the ER stress-specific eIF-2alpha kinase; ATF6, an ER stress-induced transcription factor; and its proapoptotic target, CHOP/GADD153. Tunicamycin also induced significant cytotoxicity, and inhibited DNA synthesis with an IC50 of 0.5–1 ug/mL in all cell lines, as well as primary LPC from 3/3 WM patients. Furthermore, tunicamycin induced apoptosis in WM cells, with an increase in the sub-G1 population notable at 12 hrs. Tunicamycin induced apoptosis was preceded by caspase-12 cleavage, followed then by caspase-8, -9 and PARP cleavage. Importantly, co-culture of WM cells with the survival factors IL-6, IGF-1 as well as BMSC did not inhibit tunicamycin induced cytotoxicity. Lastly, tunicamycin did not induce cytotoxicity in healthy donor peripheral blood mononuclear or hematopoietic stem cells. Conclusion: These pre-clinical studies provide a framework for further evaluation of ER stress inducing agents as therapeutic agents in WM.

Background: Waldenström’s Macroglobulinemia (WM) is an incurable low-grade lymphoplasmacytic lymphoma with as yet unknown genetic basis for its pathogenesis. Several TNF family members (CD40L, APRIL and BAFF/BLYS) are known to regulate WM growth and survival. TRAFs are a novel family of adapter proteins that facilitate pro-apoptotic (TACI) or pro-survival/differentiation (CD40, BAFFR, BCMA) receptor signaling mediated by TNF family ligands. Therefore, understanding the TRAF system in WM may yield important clues about WM growth and survival. Methods: WM cell lines (BCWM.1 and WSU-WM), IgM secreting low-grade lymphoma cell lines (MEK1, RL, Namalwa), and primary bone marrow CD19+ selected lymphoplasmacytic cells (LPC) from 20 WM patients and 6 healthy donors were evaluated for TRAF (TRAF 2, 3, 5, 6) expression using semi quantitative RT-PCR and/or western blot analysis. Results: The TNF familiy receptors CD40, BAFFR, BCMA, and TACI were expressed in all cell lines tested as well as in CD19+ selected LPC from WM patients and healthy donors. Moreover, TRAF 2, 3, 5, 6 were expressed in all cell lines by both RT-PCR and western blot analysis. In contrast, we observed loss or abnormally low expression of both TRAF 2 and 5 in 6/20 (30%) patients, whilst TRAF 3 was absent or abnormally low in 3/30 (15%) patients. TRAF 6 was expressed in all patients. Among healthy donors, we observed expression of all TRAF adapter proteins. Conclusion: Up to one third of WM patients demonstrate loss of TRAF 2 and 5 adapter proteins which facilitate signaling through the pro-apoptotic receptor TACI. Ongoing studies including gene sequencing and siRNA knockdown models are delineating a role for TRAF loss in the pathogenesis of WM.

Background: Waldenstrom’s Macroglobulinemia (WM) is an incurable low-grade lymphoplasmacytic lymphoma. Recently, Bortezomib has demonstrated clinical activity in patients with relapsed WM. The purpose of this study was to investigate the in vitro effect of the new proteasome inhibitor NPI-0052 (Nereus Pharmaceuticals, CA), alone and in combination with Bortezomib, in WM. Methods: WM cell lines (BCWM1 and WSU-WM) and IgM secreting low-grade lymphoma cell lines (MEK1, RL, Namalwa) were used. Bone marrow primary CD19+ malignant cells were obtained from WM patients after informed consent. Inhibition of growth was measured using MTT assays. DNA synthesis was measured using the thymidine incorporation assay. Apoptosis was determined using Apo2.7 staining, followed by flow cytometric analysis. Determination of the additive or synergistic effect of the combination was calculated using the CalcuSyn software (Biosoft, MO) based on the Chou-Talalay method with the combination index (CI) Results: NPI-0052 induced cytotoxicity and inhibition of DNA synthesis, with an IC50 of 20–30nM in all cell lines tested at 24 hrs. NPI-0052 induces 50% apoptosis at 48 hrs. Similar effects were demonstrated in primary CD19+ WM cells. Bortezomib induced cytotoxicity and inhibition of DNA synthesis with an IC50 of 20–30nM in all cell lines tested. Importantly, the combination of NPI-0052 and Bortezomib induced significant inhibition of proliferation compared to each agent alone, specifically at the combination of 2.5nM and 5nM of Bortezomib and 10nM of NPI-0052. For example, Bortezomib single agent at 2.5nM and 5 nM induced 8% and 13% cytotoxicity in BCWM.1 in vitro, respectively, while the combination Bortezomib and NPI-0052 10nM induced a synergistic cytotoxic effect, 44% (CI=0.7) and 58% (CI=0.47), respectively. The combination effect of NPI-0052 20 nM with Bortezomib 2.5nM and 5nM was also synergistic, with 61% (CI=0.7) and 66% (CI=0.7) cytotoxicity, respectively. Similar effects were observed in 3 primary CD19+ WM cells obtained from patients’ bone marrow. Conclusion: NPI-0052 has significant anti-tumor activity against WM in vitro, especially in combination with Bortezomib. These results provide the framework to further study the potential therapeutic role of NPI-0052 in WM. *XJ and XL are co-first authors.

Background: Waldenstrom Macroglobulinemia (WM) is characterized by widespread involvement of the bone marrow (BM), and lymphadenopathy in 20% of the patients, implying continuous trafficking of WM cells into and out of the BM and lymph nodes. The normal process of B-cell homing is regulated by cytokines, chemokines, and adhesion molecules. One of the most extensively studied chemokines in migration is stromal derived factor SDF-1 and its receptor CXCR4. Here we study the role of chemokine receptors, and the SDF-1/CXCR4 axis on migration and adhesion in WM. Methods: Flow cytometry for CXC and CC chemokine receptors (CXCR1, CXCR2, CXCR3, CXCR4, CXCR5, CCR2, CCR4, CCR5, CCR6 and CCR7), and adhesion molecules (VLA-4 and LFA-1) on WM cell lines (BCWM.1 and WM-WSU) and patient samples was performed. Migration was determined using the transwell migration assay (Costar, NY). Cells were placed in the upper chambers of the migration assay with 1% FCS medium in the presence of serial concentrations of SDF-1 in the lower chambers. After 4 hours of incubation, cells that migrated to the lower chambers were counted. Similarly, adhesion was determined using an adhesion assay (EMD Biosciences, San Diego, CA) with 96-well plated coated with fibronectin. Immunoblotting for proteins downstream of CXCR4 was performed. The CXCR4 inhibitor AMD3100 (10–100uM, Sigma, MO) and Gi protein inhibitor pertussis toxin PTX (10–200ng/ml, Sigma, MO) were used to inhibit CXCR4 signaling. Results: The following chemokine receptors were expressed on patient CD19+WM cells with over 30% expression: CXCR1 (mean 60%), CXCR2 (mean 47%), CXCR4 (mean 47%), CXCR5 (mean 69%), CCR4 (mean 54%) and CCR6 (mean 61%). Similar expression was observed on WM cell lines. We next determined the effect of SDF-1 on migration and signaling pathways in WM. SDF-1 (10–100nM) induced migration in a bell-shaped curve with 30nM inducing maximum migration (110% compared to control). SDF-1 30nM induced a rapid activation of signaling pathways downstream of CXCR4 including pERK1/2, pAKT, and pPKC at 1 min, with maximum activation at 5min. The CXCR4 inhibitor AMD3100 inhibited migration of BCWM.1 in the presence of 30nM SDF-1, with AMD3100 10uM inhibiting migration at 59% of control, and 20 to 50uM leading to a plateau in inhibition of migration at 54% of control. AMD3100 inhibited pERK and pPKC activation, downstream of CXCR4 in a dose-dependent fashion. Similar results were observed using PTX, with inhibition of migration of WM cells at 50% compared to control. To determine the role of SDF-1 on adhesion, we first demonstrated that WM cells from patients and cell lines expressed high levels of surface VLA-4 expression (mean 95% surface expression). WM cells had an increase in adhesion to fibronectin (VLA-4 ligand) compared to BSA control. AMD3100 10uM inhibited adhesion to fibronectin (63 % of control), indicating that the SDF-1/CXCR4 axis regulates adhesion. Conclusion: CXCR4 is highly expressed on WM cells and regulates migration and adhesion, indicating a potential role in regulating WM trafficking into the BM and lymph nodes. These studies provide the preclinical framework to study CXCR4 inhibitors in the regulation of homing and adhesion in WM.

Background: We have previously demonstrated activity of the new Akt inhibitor perifosine (NSC 639966; Keryx, NY) in Waldenstrom’s Macroglobulinemia (WM). Perifosine induced complete inhibition of Akt phosphorylation along with induction of apoptosis in WM cells. However, MAPK pathways and PKC proteins were activated in response to perifosine. MAPK and PKC pathways are known to promote cell proliferation. Therefore, understanding the mechanism by which perifosine induces MEK/ERK and PKC activation is important to better understand the mechanisms of response/resistance to this novel agent in ongoing clinical trials. Methods: WM cell lines (BCWM.1, WM-WSU) were treated with perifosine or with the specific Akt inhibitor Triciribine (Biomol, PA). In addition, knockdown of Akt was performed using shRNA silencing techniques (lentivirus shRNA vector, Invitrogen, Ca). The following inhibitors were also used: PI3K inhibitor LY294002 (Calbiochem, CA) and MEK inhibitor (U0126, Calbiochem, CA). Inhibition of proliferation was measured using the MTT assay. Immunoblotting was performed at different time points. Results: Perifosine induced cytotoxicity in WM cells and induced MEK/ERK activation and pPKC activation in a dose and time dependent fashion. We then treated WM cells with perifosine in the presence or absence of the MEK inhibitor U0126 and demonstrated that the combination of the two agents induced significant synergistic activity. We sought to identify the molecular mechanism by which perifosine induces MEK/ERK activation. We demonstrated that the specific AKT inhibitor Triciribine inhibited AKT and induced cytotoxicity in WM cells in a similar fashion to perifosine. However, unlike perifosine, it did not enhance MEK/ERK activity. Similarly, using Akt shRNA, we demonstrated that, despite inhibition of Akt activation, MEK/ERK was not activated. These data indicate that the effect of perifosine on MEK/ERK pathway is not through a compensatory feedback mechanism of Akt inhibition as previously thought. Therefore, we hypothesized that the effect of perifosine on the MEK/ERK pathway is through modulation of upstream pathways, specifically PI3K, PKC and c-Raf/MEK pathways. We first demonstrated that the specific PI3K inhibitor LY294002 (25mM for 15 minutes) completely abrogated Akt phosphorylation, while inducing significant ERK activation, indicating that the effect of perifosine on MEK/ERK may be similar to that of LY294002. We also demonstrated that perifosine and LY294002 activated c-Raf and pan-pPKC at 4 hrs. Conclusion: Based on this, we believe that in the presence of perifosine, growth receptor stimulation leads to PLC and RTK activation, which induces PIP2 stimulation. PIP2 is upstream of PI3K and PKC. Given that PI3K is blocked by perifosine, PIP2 leads to activation of PKC, which then induces growth stimulation, and activation of c-Raf and downstream MEK/ERK. In addition, growth receptors may also activate Raf through the Ras/Raf/MEK pathway, independent of PKC. These studies provide a better understanding of molecular mechanisms that regulate resistance to perifosine. Future combinations of perifosine with MEK inhibitors or PKC inhibitors such as AZD6244 and Enzastaurin may overcome this resistance and induce significant activity in WM.

Introduction: WM is a B-cell disorder characterized by bone marrow (BM) infiltration of lymphoplasmacytic cells (LPC), along with excess mast cells (MC) which support the growth and survival of BM LPC through multiple TNF-family ligands including CD40L, APRIL and BLyS/BAFF. Importantly, BM LPC stimulate cell surface expression of TNF-family ligands through release of sCD27 which induces CD70 on MC. We therefore have sought the development of agents which could target CD27-CD70 interactions. As such, we examined the therapeutic potential of directly targeting CD70 using the fully humanized monoclonal antibody SGN-70 (Seattle Genetics, Inc., Bothell WA). Methods-Results: As part of these studies, we used flow cytometric analysis to evaluate the expression of CD70 on primary WM patient BM LPC and MC, as well as 2 WM cell lines (BCWM.1 and WM-WSU). These studies demonstrated cell surface expression of CD70 on BM LPC and MC from 20/26 (77%) and 10/11 (90%) WM patients, respectively. We next assessed the ability of the SGN-70 antibody to eradicate primary WM LPC (n=5) and WM cell lines by assessing for direct induction of apoptosis, complement dependent cytotoxicity (CDC), antibody-dependent cell-mediated cytotoxicity (ADCC) as well as induction of TNF family ligands on primary WM MC and the LAD2 MC line. Following incubation of WM LPC with SGN-70 (0.01–20 μg/ml), no direct induction of apoptosis or CDC activity was observed. However, SGN-70 mediated significant dose-dependent ADCC against WM LPC and MC at concentrations of 0.1–20 ug/ml. Importantly, SGN-70 blocked sCD27-induced expression of CD40L and APRIL on primary WM MC and LAD2 MC. To further evaluate the therapeutic potential of SGN-70 in an in vivo model, SCID-hu mice bearing BCWM.1 WM cells were treated with SGN-70 (1 mg/kg, i.p., qOD) Serum human IgM and sCD27 levels were measured by ELISA to monitor for tumor engraftment and disease progression. SGN-70 initiated 6 weeks following tumor engraftment blocked tumor growth in 12/12 treated mice, whereas all 5 untreated mice demonstrated disease progression. The results of these studies provide the framework for clinical trials to examine the therapeutic potential of the SGN-70 monoclonal antibody in WM.

Background: Waldenstrom’s Macroglobulinemia (WM) is a low-grade lymphoplasmacytic lymphoma with limited options of therapy. The PI3k/Akt pathway is a critical regulator of cell survival. Our previous studies using proteomic analysis have demonstrated upregulation of members of the PI3k/Akt pathway in WM. We examined whether the new Akt inhibitor perifosine (NSC 639966; Keryx, NY) induces cytotoxicity in WM. Methods: WM cell lines (BCWM1 and WSU-WM) and IgM secreting low-grade lymphoma cell lines (MEC1, RL) were used. Primary CD19+ malignant cells were obtained from patients after informed consent. Inhibition of proliferation was measured using the MTT assay; DNA synthesis was measured using the thymidine uptake assay and apoptosis using Apo2.7 flow cytometry. Bone marrow stromal cells (BMSC) confer growth and resistance to conventional treatments. We therefore, tested the effect of perifosine on WM cells co-cultured with BMSC. Immunoblotting for signaling pathways was performed at different time (30 minutes to 16 hrs) and doses of therapy. In vivo activity of perifosine was assessed using a SCID-irradiated model with subcutaneous tumors in which perifosine was administered by oral gavage daily (35 mg/kg/day). A two-sided t-test was used to determine statistical differences. Results: Perifosine inhibited phosphorylation of Akt in a dose- and time- dependent fashion, as well as downstream GSK3a/b and ribosomal phospho-S6. Perifosine inhibited Akt activity as confirmed by Akt kinase assay. Perifosine induced significant cytotoxicity and inhibition of DNA synthesis with an IC50 of 5-20uM in all cell lines tested. Similar effects were observed in primary CD19+ patient WM cells. Perifosine induced apoptosis in WM cells as demonstrated by flow cytometry. The mechanism of apoptosis induced by perifosine was through activation of SAPK/JNK pathway, followed by caspase-8, -9 and PARP cleavage. The JNK inhibitor SP600125 abrogated perifosine-induced apoptosis. The growth inhibitory effects of perifosine were significant even in the presence of BMSC, IL-6 and IGF-1, which induce resistance to conventional therapies. Importantly, perifosine did not induce cytotoxicity in healthy donor peripheral blood mononuclear cells or in hematopietic stem cells in a methylcellulose colony forming cell assay, indicating lack of toxicity on normal cells. Interestingly, MAPK members such as MEK/ERK were activated by perifosine. The MEK inhibitor U0126 significantly enhanced perifosine-induced cytotoxicity in WM cells, indicating that this combination may be synergistic in vivo. Finally, perifosine induced significant reduction in WM tumor growth in vivo, as compared to control cohort treated with vehicle only at week 6 (p=0.05). Conclusion: Perifosine has significant antitumor activity in WM both in vitro and in vivo. These results provide the framework for clinical evaluation of perifosine in WM. Supported in part by the Leukemia and Lymphoma Society, the Lymphoma Research Foundation and an American Society of Hematology Scholar Award. * XL and XJ are co-first authors.

Background: Waldenstrom’s Macroglobulinemia is an incurable lymphoplasmacytic lymphoma with limited options of therapy. We have previously demonstrated upregulation of PKCβ protein in WM using protein array techniques, and confirmed increased expression in WM using immunohistochemistry. PKCβ regulates cell survival and growth, as well as migration and homing in many B-cell malignancies. We therefore hypothesized that inhibition of PKCβ will induce cytotoxicity in WM. Methods: In this study, we examined the effect of serial dilutions of the PKCβ enzastaurin (2.5 uM to 20 uM) on WM cell lines (BCWM1 and WM-WSU), IgM secreting low-grade lymphoma cell lines (MEC-1, RL), as well as primary CD19+ WM cells and WM cells adherent to bone marrow stromal cells (BMSCs), which induce resistance to conventional therapy. Cytotoxicity was measured by MTT assay and inhibition of cell proliferation was determined by thymidine uptake assay. Apoptosis was measured by flow cytometry using Annexin V and DAPI staining at 48 h. Cell DNA content analysis was performed using DAPI staining on fresh cells. Cell signaling pathways targeted by enzastaurin were determined using immunoblotting at 6 h (2.5 to 10 uM) and at 7.5 uM (10 min to 12 h). The effect of enzastaurin in vivo was determined using a subcutaneous WM model in SCID mice. Enzastaurin was given by oral gavage (80mg/kg twice daily). Results: Enzastaurin demonstrated time and dose-dependent inhibition of PKCβ in WM cells. It induced a significant decrease of proliferation at 24 and 48 h in all cell lines tested with an IC50 of 2.5 to 10 uM, even in the presence of DOPPA, a specific PKCβ stimulator. Similar effects were demonstrated in primary CD19+ WM cells, with no cytotoxicity on peripheral blood mononuclear cells indicating selective toxicity on malignant cells. Enzastaurin induced dose-dependent apoptosis at 24 and 48 h with induction of caspases 3, 8, 9 and PARP cleavage as well as a decrease in Bcl-xL. Analysis of cell DNA content confirmed apoptosis at low doses of enzastaurin (5 uM). To further determine the mechanism of action of enzastaurin in WM, we examined downstream molecules. It significantly inhibited AKT phosphorylation and AKT kinase activity, as determined by inhibition of phosphorylation of GSKα/β fusion protein. In addition, enzastaurin inhibited p-MARCK, and ribosomal p-S6. Enzastaurin overcame resistance induced by co-culture of WM cells with bone marrow stromal cells. In addition, enzastaurin (2.5 to 5 uM) in combination with bortezomib (2.5 to 10 nM), another active agent in WM, demonstrated strong synergistic activity using the Calcusyn software for synergy. Given that PKCβ regulates migration and homing of B-cells, we next determined the effect of enzastaurin on in vitro migration of WM cells. In the transwell migration assay, enzastaurin inhibited migration in a dose-dependent fashion (p=0.041). Finally, in vivo animal studies demonstrated significant inhibition of WM tumor growth in the enzastaurin treated mice (n=11), compared to control mice (n=8) (p=0.028). Conclusion: Enzastaurin has significant antitumor activity in WM in vitro and in vivo, providing the framework for clinical trials evaluating enzastaurin as a new therapeutic agent in patients with WM.

The authors report 7 cases of bone marrow necrosis during hematological malignant diseases: 3 leukemia, 4 lymphoid malignancies. The main clinical features were bone pain and fever. The bone marrow aspiration and/or biopsy allow diagnosis. The prognosis was in all cases very poor.

We report a case of periosteal bone formation of elbow in the Wegener's granulomatosis. The pathology of the periostitis shows a granuloma with focal lesions of vasculitis. An improvement was obtained only with radiotherapy.

A short synthesis of 4-alkoxylated isoindolin-1-ones based upon the S N Ar reaction applied to phosphorylated 2-methoxybenzamides followed by alkaline cleavage of the phosphoryl auxiliary is reported.

Background: The current most powerful prognosis model in Multiple Myeloma (MM) combines beta-2 microglobulin (b2m) with albumin, corresponding to the International Staging System (ISS). However, the prognosis of patients within the group I of ISS (high albumin and low b2m) may vary. Proliferative activity of plasma cells has been previously related to prognosis in MM, but methods proposed so far are difficult to apply in routine practice. Ki-67 is a nuclear protein associated with cell proliferation, and its expression is reported as a powerful prognosis marker in solid tumours and several hematological malignancies. We retrospectively evaluated the % of bone marrow plasma cells (BMPC) expressing Ki-67 antigen (Ki67 index) in a series of 174 untreated patients with MM at diagnosis and we looked for its prognostic value on survival in MM. Method: Ki-67 index was determined after double immunocytochemistry on PC from BM cytospins (ABC peroxidase to identify cells expressing Ki-67, and alkaline phosphatase to identify PC expressing either Kappa or Lambda light chain). Conventional cytogenetic study and interphase FISH (research of Rb1 gene deletion) were performed in 114 and in 128 pts respectively. Results: Median survival (± se; months) for pts with stage III, II, and stage I of ISS score were 20 (± 3), 41 (± 3), 51 (± 3) months, respectively (p Conclusion: Ki-67 index is easy to perform in routine practice, and is a good prognostic marker, which provides additional survival prognostic information to b2m into the ISS model.

Objective The Covid‐19 pandemic is rapidly spreading worldwide, notably in Europe and North America, where obesity is highly prevalent. The relation between obesity and severe acute respiratory syndrome coronavirus‐2 (SARS‐CoV‐2) has not been fully documented. Methods In this retrospective cohort study we analyzed the relationship between clinical characteristics, including body mass index (BMI), and the requirement for invasive mechanical ventilation (IMV) in 124 consecutive patients admitted in intensive care for SARS‐CoV‐2, in a single French center. Results Obesity (BMI >30 kg/m2) and severe obesity (BMI >35 kg/m2) were present in 47.6% and 28.2% of cases, respectively. Overall, 85 patients (68.6%) required IMV. The proportion of patients who required IMV increased with BMI categories (p35 kg/m2 (85.7%). In multivariate logistic regression, the need for IMV was significantly associated with male sex (p35 kg/m2 vs patients with BMI

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