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The neurohormonal control of body weight involves a complex interplay between long-term adiposity signals (e.g., leptin), and short-term satiation signals (e.g., amylin). In diet-induced obese (DIO) rodents, amylin/leptin combination treatment led to marked, synergistic, fat-specific weight loss. To evaluate the weight-lowering effect of combined amylin/leptin agonism (with pramlintide/metreleptin) in human obesity, a 24-week, randomized, double-blind, active-drug-controlled, proof-of-concept study was conducted in obese or overweight subjects (N = 177; 63% female; 39 ± 8 years; BMI 32.0 ± 2.1 kg/m2; 93.3 ± 13.2 kg; mean ± s.d.). After a 4-week lead-in period with pramlintide (180 µg b.i.d. for 2 weeks, 360 µg b.i.d. thereafter) and diet (40% calorie deficit), subjects achieving 2–8% weight loss were randomized 1:2:2 to 20 weeks of treatment with metreleptin (5 mg b.i.d.), pramlintide (360 µg b.i.d.), or pramlintide/metreleptin (360 µg/5 mg b.i.d.). Combination treatment with pramlintide/metreleptin led to significantly greater weight loss from enrollment to week 20 (−12.7 ± 0.9%; least squares mean ± s.e.) than treatment with pramlintide (−8.4 ± 0.9%; P < 0.001) or metreleptin (−8.2 ± 1.3%; P < 0.01) alone (evaluable, N = 93). The greater reduction in body weight was significant as early as week 4, and weight loss continued throughout the study, without evidence of a plateau. The most common adverse events with pramlintide/metreleptin were injection site events and nausea, which were mostly mild to moderate and decreased over time. These results support further development of pramlintide/metreleptin as a novel, integrated neurohormonal approach to obesity pharmacotherapy. [ABSTRACT FROM AUTHOR]

Determines whether ubiquitin conjugation is necessary for the degradation of oxidized proteins in intact cells. Inhibition of degradation by proteasome inhibitors; Rates of oxidized protein degradation by cell lysates; Presence of adenosine triphosphate; Tendency of a protein to be ubiquitinylated.

A third of patients with type 2 diabetes (T2D) are estimated to have nonalcoholic steatohepatitis (NASH). There is a high unmet need for safe and effective therapies that can address liver health and metabolic comorbidities in NASH patients. Efruxifermin (EFX), a long-acting Fc-FGF21 fusion protein, demonstrated robust reductions in liver fat content, markers of liver injury and fibrosis, and improved lipid and glucose metabolism in patients with NASH and fibrosis stage 1-3.1 Patients (N=80) were randomized to receive placebo or 28, 50, or 70mg EFX for 16 weeks, and continued on their existing antidiabetic medications. The aim of this analysis was to evaluate the effects of EFX on markers of glucose metabolism in patients with NASH and in the subgroup with T2D (N=41). Mean age, BMI and HbA1c at baseline were 52y, 37.6 kg/m2 and 6.3% in the overall study population, and 53y, 38.1 kg/m2, and 7.0% in the T2D subgroup. Clinically meaningful improvements in glycemic control were observed in the T2D subgroup (Table B), consistent with improvements in markers of glucose metabolism in the overall population (Table A), and with the insulin-sensitizing actions of EFX. Considering the prevalence of T2D in NASH, the ability to improve glycemic control over existing medications is a desirable attribute for future NASH therapies. 1Harrison et. al. 2020. Hepatology, 72; 1S; 6A Disclosure: J. Frias: Consultant; Self; 89bio, Inc., Altimmune, Axcella Health Inc., Boehringer Ingelheim Pharmaceuticals, Inc., Eli Lilly and Company, Gilead Sciences, Inc., Intercept Pharmaceuticals, Inc., Merck & Co., Inc., Novo Nordisk, Pfizer Inc., Sanofi, Research Support; Self; AstraZeneca, Boehringer Ingelheim Pharmaceuticals, Inc., Bristol-Myers Squibb Company, CymaBay Therapeutics, Eli Lilly and Company, Intercept Pharmaceuticals, Inc., Janssen Pharmaceuticals, Inc., Madrigal Pharmaceuticals, Inc., Merck & Co., Inc., Novartis Pharmaceuticals Corporation, Novo Nordisk, Pfizer Inc., Sanofi, Speaker's Bureau; Self; Merck & Co., Inc., Sanofi. S. A. Harrison: Consultant; Self; Axcella Health Inc. R. Shringarpure: Employee; Self; Akero Therapeutics, Inc., Stock/Shareholder; Self; Akero Therapeutics, Inc. E. J. Tillman: Employee; Self; Akero Therapeutics, Inc., Stock/Shareholder; Self; Akero Therapeutics, Inc. C. Hu: None. E. Fong: Employee; Self; Akero Therapeutics, Inc. B. De temple: Employee; Self; Akero Therapeutics, Inc. T. Rolph: Employee; Self; Akero Therapeutics, Inc., Stock/Shareholder; Self; Pfizer Inc. A. Cheng: Employee; Self; Akero Therapeutics, Inc. K. Yale: Employee; Self; Akero Therapeutics, Inc. [ABSTRACT FROM AUTHOR]

FGF21, an endocrine hormone that regulates whole-body metabolism during energy imbalance, is a promising therapeutic target. Efruxifermin (EFX), an Fc-FGF21 analog, is a balanced FGFR1c, 2c, and 3c agonist under investigation as a potential treatment for nonalcoholic steatohepatitis (NASH). In a clinical trial in biopsy-confirmed NASH, EFX significantly reduced liver fat content (LFC), ALT, and AST, and increased adiponectin.1 Activating FGFR1c in adipose tissue increases circulating adiponectin; the aim of this analysis was to evaluate correlations between changes in adiponectin and markers of dyslipidemia, glucose metabolism and liver health following EFX treatment. Patients (N=80) were randomized to placebo or 28, 50, or 70mg EFX. Larger increases in adiponectin correlated with greater improvements in lipid profiles, including decreases in triglycerides and increases in HDL-C, as well as decreases in LFC (Table). Increases in adiponectin also correlated strongly with markers of improved glucose metabolism, and greater reductions in markers of liver injury and fibrosis. These data suggest adipose tissue-mediated effects of EFX contribute substantially to restoration of liver health, healthy lipoprotein profiles, insulin sensitivity and glucose tolerance. 1 Harrison 2020 Hepatol 72 1S; 6A Disclosure: J. Frias: Consultant; Self; 89bio, Inc., Altimmune, Axcella Health Inc., Boehringer Ingelheim Pharmaceuticals, Inc., Eli Lilly and Company, Gilead Sciences, Inc., Intercept Pharmaceuticals, Inc., Merck & Co., Inc., Novo Nordisk, Pfizer Inc., Sanofi, Research Support; Self; AstraZeneca, Boehringer Ingelheim Pharmaceuticals, Inc., Bristol-Myers Squibb Company, CymaBay Therapeutics, Eli Lilly and Company, Intercept Pharmaceuticals, Inc., Janssen Pharmaceuticals, Inc., Madrigal Pharmaceuticals, Inc., Merck & Co., Inc., Novartis Pharmaceuticals Corporation, Novo Nordisk, Pfizer Inc., Sanofi, Speaker's Bureau; Self; Merck & Co., Inc., Sanofi. E. J. Tillman: Employee; Self; Akero Therapeutics, Inc., Stock/Shareholder; Self; Akero Therapeutics, Inc. R. Shringarpure: Employee; Self; Akero Therapeutics, Inc., Stock/Shareholder; Self; Akero Therapeutics, Inc. E. Fong: Employee; Self; Akero Therapeutics, Inc. B. De temple: Employee; Self; Akero Therapeutics, Inc. T. Rolph: Employee; Self; Akero Therapeutics, Inc., Stock/Shareholder; Self; Pfizer Inc. A. Cheng: Employee; Self; Akero Therapeutics, Inc. K. Yale: Employee; Self; Akero Therapeutics, Inc. S. A. Harrison: Consultant; Self; Axcella Health Inc. [ABSTRACT FROM AUTHOR]

Background & Aims: Efruxifermin has shown clinical efficacy in patients with non-alcoholic steatohepatitis (NASH) and F1-F3 fibrosis. The primary objective of the BALANCED Cohort C was to assess the safety and tolerability of efruxifermin in patients with compensated NASH cirrhosis., Methods: Patients with NASH and stage 4 fibrosis (n = 30) were randomized 2:1 to receive efruxifermin 50 mg (n = 20) or placebo (n = 10) once-weekly for 16 weeks. The primary endpoint was safety and tolerability of efruxifermin. Secondary and exploratory endpoints included evaluation of non-invasive markers of liver injury and fibrosis, glucose and lipid metabolism, and changes in histology in a subset of patients who consented to end-of-study liver biopsy., Results: Efruxifermin was safe and well-tolerated; most adverse events (AEs) were grade 1 (n = 7, 23.3%) or grade 2 (n = 19, 63.3%). The most frequent AEs were gastrointestinal, including transient, mild to moderate diarrhea, and/or nausea. Significant improvements were noted in key markers of liver injury (alanine aminotransferase) and glucose and lipid metabolism. Sixteen-week treatment with efruxifermin was associated with significant reductions in non-invasive markers of fibrosis including Pro-C3 (least squares mean change from baseline [LSMCFB] -9 μg/L efruxifermin vs.  -3.4 μg/L placebo; p  = 0.0130) and ELF score (-0.4 efruxifermin vs.  +0.4 placebo; p  = 0.0036), with a trend towards reduced liver stiffness (LSMCFB -5.7 kPa efruxifermin vs.  -1.1 kPa placebo; n.s.). Of 12 efruxifermin-treated patients with liver biopsy after 16 weeks, 4 (33%) achieved fibrosis improvement of at least one stage without worsening of NASH, while an additional 3 (25%) achieved resolution of NASH, compared to 0 of 5 placebo-treated patients., Conclusions: Efruxifermin appeared safe and well-tolerated with encouraging improvements in markers of liver injury, fibrosis, and glucose and lipid metabolism following 16 weeks of treatment, warranting confirmation in larger and longer term studies., Lay Summary: Cirrhosis resulting from non-alcoholic steatohepatitis (NASH), the progressive form of non-alcoholic fatty liver disease, represents a major unmet medical need. Currently there are no approved drugs for the treatment of NASH. This proof-of-concept randomized, double-blind clinical trial demonstrated the potential therapeutic benefit of efruxifermin treatment compared to placebo in patients with cirrhosis due to NASH., Clinical Trial Number: NCT03976401., Competing Interests: Stephen A. Harrison holds a leadership or fiduciary role at, advises, consults for, receives grants or contracts from Northsea Therapeutics. He advises, consults for, receives grants or contracts, support for attending meetings and/or travel from Madrigal Pharmaceuticals, Inc. He advises, consults for, and receives grants or contracts from Akero Therapeutics, Inc. He advises, consults for, and receives grants or contracts from Axcella Health, Inc., Cymabay Therapeutics, Inc., Galectin Therapeutics, Inc., Hepion Pharmaceuticals, Inc., Hightide Therapeutics, Inc., Intercept Pharmaceuticals, Inc., Metacrine Inc., NGM Biopharmaceuticals Inc., Genfit Corp, Novo Nordisk, Poxel, Sagimet Biosciences. He advises and receives grants or contracts from Gilead Sciences, Inc., Galmed Research & Dev. LTD., and Novartis Pharmaceuticals Corp. He consults for and receives grants or contracts from Viking Therapeutics, Inc. and Enyo Pharma S.A. He advises and consults for Altimmune, Echosens North America Inc. Foresite Labs, LLC, HistoIndex PTE LTD, Medpace Inc., Prometic, Pharma SMT LTD, Ridgeline and Sonic Incytes Medical Corp, Terns Inc. He advises for 89bio, Arrowhead, Chronwell, CiVi, Indalo, PathAI, and Theratechnologies. He consults for AgomAB, Alentis Therapeutics AG, Alimentiv, Inc, Boston Pharmaceuticals, B Riley FBR Inc. BVF Partners LP, Cohbar, Inc. Canfite, Corcept Therapeutics, Inc, Fibronostics, Fortress Biotech, Inc GNS, Inipharm, Ionis, Kowa Research Institute, Microba, Nutrasource, Perspectum Diagnostics, and Piper Sandler. He receives grants or contracts from Cirius Therapeutics, Inc., and CiVi Biopharma Inc. He holds stock or stock options at Akero Therapeutics, Inc., Chronwell Inc., Cirius Therapeutics, Inc, Galectin Therapeutics, Inc., Genfit Corp, Hepion Pharmaceuticals Inc., HistoIndex PTE LTD, Metacrine Inc., NGM Biopharmaceuticals., Northsea Therapeutics B.V, and Sonic Incytes Medical Corp. Peter J. Ruane: none. Bradley Freilich: none. Guy Neff has received payment or honoraria from Intercept Pharmaceuticals. Rashmee Patil has received grants to institution from 89 Bio, AltImmune, Boehringer Ingelheim, Bristol Myers Squibb, Corcept Therapeutics, Fibronostics, Galectin Therapeutics, Genentech, Gilead, Helio Health, Hepagene, Madrigal Pharmaceuticals, NGMBio, NorthSea Therapeutics, Poxel, Sagimet Biosciences, and Viking Therapeutics. He consults for Intercept Pharmaceuticals. Cynthia Behling has received payment via Pacific Rim Pathology for liver biopsy scoring. She has received grants as a co-investigator under N100 K U01 DK61734. She has received honoraria for lectures from Pfizer and Alimentev. She is a co-chair on NASH CRN Pathology Committee. Chen Hu: none. Reshma Shringarpure, Brittany de Temple, Erica Fong, Erik J. Tillman, Timothy Rolph, Andrew Cheng, and Kitty Yale are employees of Akero Therapeutics and own stock and/or stock options of Akero Therapeutics. Please refer to the accompanying ICMJE disclosure forms for further details., (© 2022 The Author(s).)

Protein tyrosine kinases of the Janus kinase (JAK) family are associated with many cytokine receptors, which, on ligand binding, regulate important cellular functions such as proliferation, survival, and differentiation. In multiple myeloma, JAKs may be persistently activated due to a constant stimulation by interleukin (IL)-6, which is produced in the bone marrow environment. INCB20 is a synthetic molecule that potently inhibits all members of the JAK family with a 100- to 1,000-fold selectivity for JAKs over >70 other kinases. Treatment of multiple myeloma cell lines and patient tumor cells with INCB20 resulted in a significant and dose-dependent inhibition of spontaneous as well as IL-6-induced cell growth. Importantly, multiple myeloma cell growth was inhibited in the presence of bone marrow stromal cells. The IL-6 dependent cell line INA-6 was particularly sensitive to the drug (IC50<1 micromol/L). Growth suppression of INA-6 correlated with an increase in the percentage of apoptotic cells and inhibition of signal transducer and activator of transcription 3 phosphorylation. INCB20 also abrogated the protective effect of IL-6 against dexamethasone by blocking phosphorylation of SHP-2 and AKT. In contrast, AKT phosphorylation induced by insulin-like growth factor-I remained unchanged, showing selectivity of the compound. In a s.c. severe combined immunodeficient mouse model with INA-6, INCB20 significantly delayed INA-6 tumor growth. Our studies show that disruption of JAKs and downstream signaling pathways may both inhibit multiple myeloma cell growth and survival and overcome cytokine-mediated drug resistance, thereby providing the preclinical rationale for the use of JAK inhibitors as a novel therapeutic approach in multiple myeloma.

Multiple myeloma is a B-cell malignancy for which no curative therapies exist to date, despite enormous research efforts. The remarkable activity of the proteasome inhibitor bortezomib (PS-341, Velcade) observed in clinical trials of patients with relapsed refractory myeloma has led to investigations of the role of the ubiquitin-proteasome pathway in the pathogenesis of myeloma. Here we report a biochemical analysis of proteasome activity and composition in myeloma cells exposed to PS-341 in the presence or absence of cytokines present in the bone marrow milieu. We observed that the myeloma cell lines MM1.S, RPMI8226, and U266 contain active immunoproteasomes, the amount of which is enhanced by IFN-gamma and tumor necrosis factor-alpha. Using a radiolabeled active site-directed probe specific for proteasome catalytic subunits, we show that PS-341 targets the beta5 and beta1 subunits in a concentration-dependent manner. Furthermore, PS-341 also targeted the corresponding catalytic subunits of the immunoproteasome, beta5i and beta1i, respectively. These data suggest that PS-341 targets both normal and immunoproteasome species to a similar extent in myeloma cells.

Topoisomerase I inhibitors are effective anticancer therapies and have shown activity in hematologic malignancies. Here we show for the first time that SN38, the potent active metabolite of irinotecan, induces c-Jun NH(2)-terminal kinase activation, Fas up-regulation, and caspase 8-mediated apoptosis in multiple myeloma (MM) cells. Proteasomal degradation of nuclear topoisomerase I has been proposed as a resistance mechanism in solid malignancies. SN38-induced proteasomal degradation of topoisomerase I was observed during SN38-mediated cytotoxicity against MM.1S myeloma cell line but occurred after c-Jun NH(2)-terminal kinase activation, Fas up-regulation, and poly(ADP-ribose) polymerase cleavage and failed to protect cells from apoptosis. Differential toxicity was observed against MM cells versus bone marrow stromal cells, and SN38 inhibited adhesion-induced up-regulation of MM cell proliferation when MM cells adhere to bone marrow stromal cells. In addition, SN38 directly inhibited constitutive and inducible interleukin 6 and vascular endothelial growth factor secretion by bone marrow stromal cells. Synergy was observed when SN38 was used in combination with doxorubicin, bortezomib, as well as poly(ADP-ribose) polymerase inhibitor NU1025 and Fas-activator CH11. These findings have clinical significance, because identification of downstream apoptotic signaling after topoisomerase I inhibition will both elucidate mechanisms of resistance and optimize future combination chemotherapy against MM.

We recently demonstrated that caveolae, vesicular flask-shaped invaginations of the plasma membrane, represent novel therapeutic targets in multiple myeloma. In the present study, we demonstrate that vascular endothelial growth factor (VEGF) triggers Src-dependent phosphorylation of caveolin-1, which is required for p130(Cas) phosphorylation and multiple myeloma cell migration. Conversely, depletion of caveolin-1 by antisense methodology abrogates p130(Cas) phosphorylation and VEGF-triggered multiple myeloma cell migration. The proteasome inhibitor bortezomib both inhibited VEGF-triggered caveolin-1 phosphorylation and markedly decreased caveolin-1 expression. Consequently, bortezomib inhibited VEGF-induced multiple myeloma cell migration. Bortezomib also decreased VEGF secretion in the bone marrow microenvironment and inhibited VEGF-triggered tyrosine phosphorylation of caveolin-1, migration, and survival in human umbilical vascular endothelial cells. Taken together, these studies demonstrate the requirement of caveolae for VEGF-triggered multiple myeloma cell migration and identify caveolin-1 in multiple myeloma cells and human umbilical vascular endothelial cells as a molecular target of bortezomib.

Smac, second mitochondria-derived activator of caspases, promotes apoptosis via activation of caspases. Heat shock protein 27 (Hsp27) negatively regulates another mitochondrial protein, cytochrome c, during apoptosis; however, the role of Hsp27 in modulating Smac release is unknown. Here we show that Hsp27 is overexpressed in both dexamethasone (Dex)-resistant multiple myeloma (MM) cell lines (MM.1R, U266, RPMI-8226) and primary patient cells. Blocking Hsp27 by an antisense (AS) strategy restores the apoptotic response to Dex in Dex-resistant MM cells by triggering the release of mitochondrial protein Smac, followed by activation of caspase-9 and caspase-3. Moreover, AS-Hsp27 overcomes interleukin-6 (IL-6)-mediated protection against Dex-induced apoptosis. These data demonstrate that Hsp27 inhibits the release of Smac, and thereby confers Dex resistance in MM cells.

Bortezomib (PS-341), a selective inhibitor of proteasome, induces apoptosis in various tumor cells, but its mechanism of action is unclear. Treatment with PS-341 induces apoptosis in SUDHL6 (DHL6), but not SUDHL4 (DHL4), lymphoma cells. Microarray analysis shows high RNA levels of heat shock protein-27 (Hsp27) in DHL4 versus DHL6 cells, which correlates with Hsp27 protein expression. Blocking Hsp27 using an antisense strategy restores the apoptotic response to PS-341 in DHL4 cells; conversely, ectopic expression of wild-type Hsp27 renders PS-341-sensitive DHL6 cells resistant to PS-341. These findings provide the first evidence that Hsp27 confers PS-341 resistance.

Insulin-like growth factor-1 (IGF-I) is a growth and survival factor in human multiple myeloma (MM) cells. Here we examine the effect of IGF-I on MM cell adhesion and migration, and define the role of beta1 integrin in these processes. IGF-I increases adhesion of MM.1S and OPM6 MM cells to fibronectin (FN) in a time- and dose-dependent manner, as a consequence of IGF-IR activation. Conversely, blocking anti-beta1 integrin monoclonal antibody, RGD peptide, and cytochalasin D inhibit IGF-I-induced cell adhesion to FN. IGF-I rapidly and transiently induces association of IGF-IR and beta1 integrin, with phosphorylation of IGF-IR, IRS-1, and p85(PI3-K). IGF-I also triggers phosphorylation of AKT and ERK significantly. Both IGF-IR and beta1 integrin colocalize to lipid rafts on the plasma membrane after IGF-I stimulation. In addition, IGF-I triggers polymerization of F-actin, induces phosphorylation of p125(FAK) and paxillin, and enhances beta1 integrin interaction with these focal adhesion proteins. Importantly, using pharmacological inhibitors of phosphatidylinositol 3'-kinase (PI3-K) (LY294002 and wortmannin) and extracellular signal-regulated kinase (PD98059), we demonstrate that IGF-I-induced MM cell adhesion to FN is achieved only when PI3-K/AKT is activated. IGF-I induces a 1.7-2.2 (MM.1S) and 2-2.5-fold (OPM6) increase in migration, whereas blocking anti-IGF-I and anti-beta1 integrin monoclonal antibodies, PI3-K inhibitors, as well as cytochalasin D abrogate IGF-I-induced MM cell transmigration. Finally, IGF-I induces adhesion of CD138+ patient MM cells. Therefore, these studies suggest a role for IGF-I in trafficking and localization of MM cells in the bone marrow microenvironment. Moreover, they define the functional association of IGF-IR and beta1 integrin in mediating MM cell homing, providing the preclinical rationale for novel treatment strategies targeting IGF-I/IGF-IR in MM.