IntroductionTargeted mAb-based therapies provide effective and safe treatments for hematologic malignancies. Rituximab, which specifically targets the B-cell antigen CD20, has had the greatest success, revolutionizing the treatment of the 2 most common forms of nonHodgkin lymphoma: follicular and diffuse large B-cell lymphoma. In addition, mAb-based therapies targeting CD52 (alemtuzumab) and CD33 (gemtuzumab ozogamicin) have been approved for the treatment of chronic lymphocytic leukemia and acute myelogenous leukemia, respectively. Despite the progress of these strategies, they do have limitations. Only a fraction of patients respond to rituximab, and the majority of those who do respond will eventually relapse. Treatment with alemtuzumab and gemtuzumab are limited by safety concerns, and many additional hematologic malignancies do not respond to treatment with any of these targeted therapies. Various therapies based on alternate mAbs, including second-generation anti-CD20 mAbs and those targeting alternate cell-surface proteins such as CD19, CD22, CD30, CD37, CD40, and CD74, have been developed and are at different stages of clinical testing in the hopes of providing approaches to treating a broader spectrum of hematologic malignancies that are poorly served by existing therapies. 1,2 Whereas targeting of cell-surface antigens themselves can mediate antitumor activity through the induction of apoptosis, most mAb-based activity against hematologic malignancies is reliant on either Fc-mediated effector functions such as complementdependent cytotoxicity and antibody-dependent cell-mediated cytotoxicity 3,4 or is engineered through the conjugation of an immunotoxin or radiolabeled isotope. 1 Considering the potential of naturally occurring CTLs to mediate cell lysis, various strategies have also been explored to recruit CTLs to mediate tumor cell killing. Tumor-specific CTLs exert extremely potent effects through recognition of the corresponding peptide/MHC complex recognized by their TCR, and are among the most potent cells that mediate antitumor effects. A major limitation in generating tumorspecific CTLs in vivo is that their induction requires the use of vaccine strategies, such as dendritic cell-based vaccines, 5 that are capable of breaking tolerance to cancer self-antigens. One alternative is ex vivo expansion and activation of rare, tumor-specific CTLs for reinfusion into cancer patients. 6 However, cancer cells can down-regulate MHC expression as an escape mechanism, thus preventing the ability of CTLs to recognize their antigenic peptide. The genetic manipulation of patients' T cells to express chimeric antigen receptors comprising a tumor-specific antigen and T cellactivating properties before their adoptive transfer provides a non-MHC-restricted approach to targeting cancer, as was shown recently in the treatment of lymphoma with T cells engineered to recognize CD19. 7 However, the patient-specific manipulation and risk associated with this procedure represent major limitations to its expanded use. Alt...

Current therapies for acute myeloid leukemia (AML) are largely ineffective, and AML patients may benefit from targeted immunotherapy approaches. MGD006 is a bispecific CD3xCD123 dual-affinity re-targeting (DART) molecule that binds T lymphocytes and cells expressing CD123, an antigen up-regulated in several hematological malignancies including AML. MGD006 mediates blast killing in AML samples, together with concomitant activation and expansion of residual T cells. MGD006 is designed to be rapidly cleared, and therefore requires continuous delivery. In a mouse model of continuous administration, MGD006 eliminated engrafted KG-1a cells (an AML-M0 line) in human PBMC (peripheral blood mononuclear cell)-reconstituted NSG/β2m(-/-) mice at doses as low as 0.5 μg/kg per day for ~7 days. MGD006 binds to human and cynomolgus monkey antigens with similar affinities and redirects T cells from either species to kill CD123-expressing target cells. MGD006 was well tolerated in monkeys continuously infused with 0.1 μg/kg per day escalated weekly to up to 1 μg/kg per day during a 4-week period. Depletion of circulating CD123-positive cells was observed as early as 72 hours after treatment initiation and persisted throughout the infusion period. Cytokine release, observed after the first infusion, was reduced after subsequent administrations, even when the dose was escalated. T cells from animals with prolonged in vivo exposure exhibited unperturbed target cell lysis ex vivo, indicating no exhaustion. A transient decrease in red cell mass was observed, with no neutropenia or thrombocytopenia. These studies support clinical testing of MGD006 in hematological malignancies, including AML.

Cellular hypertrophy is regulated by coordinated pro- and antigrowth machineries. Foxo transcription factors initiate an atrophy-related gene program to counter hypertrophic growth. This study was designed to evaluate the role of Akt, the forkhead transcription factor Foxo3a, and atrophy genes muscle-specific RING finger (MuRF)-1 and atrogin-1 in cardiac hypertrophy and contractile dysfunction associated with high-fat diet-induced obesity. Mice were fed a low- or high-fat diet for 6 mo along with a food-restricted high-fat weight control group. Echocardiography revealed decreased fractional shortening and increased end-systolic diameter and cardiac hypertrophy in high-fat obese but not in weight control mice. Cardiomyocytes from high-fat obese but not from weight control mice displayed contractile and intracellular Ca2+ defects including depressed maximal velocity of shortening/relengthening, prolonged duration of shortening/relengthening, and reduced intracellular Ca2+ rise and clearance. Caspase activities were greater in high-fat obese but not in weight control mouse hearts. Western blot analysis revealed enhanced basal Akt and Foxo3a phosphorylation and reduced insulin-stimulated phosphorylation of Akt and Foxo3a without changes in total protein expression of Akt and Foxo3a in high-fat obese hearts. RT-PCR and immunoblotting results displayed reduced levels of the atrogens atrogin-1 and MuRF-1, the upregulated hypertrophic markers GATA4 and ciliary neurotrophic factor receptor-alpha, as well as the unchanged calcineurin and proteasome ubiquitin in high-fat obese mouse hearts. Transfection of H9C2 myoblast cells with dominant-negative Foxo3a adenovirus mimicked palmitic acid (0.8 mM for 24 h)-induced GATA4 upregulation without an additive effect. Dominant-negative Foxo3a-induced upregulation of pAkt and repression of phosphatase and tensin homologue were abrogated by palmitic acid. These results suggest a cardiac hypertrophic response in high-fat diet-associated obesity at least in part through inactivation of Foxo3a by the Akt pathway.

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Background Pancreatic cancer remains one of the most rapidly progressive and deadly malignancies worldwide. Current treatment regimens only result in small improvements in overall survival for patients with this cancer type. CPI-613 (Devimistat), a novel lipoate analog inhibiting mitochondrial metabolism, shows the new hope for pancreatic cancer treatment as an efficient and well-tolerated therapeutic option treated alone or in combination with chemotherapy. Methods Pancreatic cancer cells growing in planar 2D cultures and 3D scaffold were used as research platforms. Cell viability was measured by MTT and alamarBlue, and apoptosis was assessed by JC-1 staining and flow cytometry with Annexin V-FITC/PI staining. The mechanism behind CPI-613 action was analyzed by western blot, transmission electron microscopy, and lipolysis assay kits, in the presence or absence of additional signaling pathway inhibitors or gene modifications. Results CPI-613 exhibits anticancer activity in pancreatic cancer cells by triggering ROS-associated apoptosis, which is accompanied by increased autophagy and repressed lipid metabolism through activating the AMPK signaling. Intriguingly, ACC, the key enzyme modulating lipid metabolism, is identified as a vital target of CPI-613, which is inactivated in an AMPK-dependent manner and influences apoptotic process upon CPI-613. Blockade or enhancement of autophagic process does not increase or blunt apoptosis to CPI-613, but inhibition of the AMPK-ACC signaling significantly attenuates apoptosis induced by CPI-613, suggesting CPI-613-mediated lipid metabolism reduction contributes to its cytotoxicity in pancreatic cancer cells. Conclusions These findings explore the critical role of lipid metabolism in apoptosis, providing new insights into the AMPK-ACC signaling axis in crosstalk between lipid metabolism and apoptosis in CPI-613 treatment.