INTRODUCTION. A local renin-angiotensin system exists in the pulmonary nodules of lymphangioleiomyomatosis patients. Sirolimus, the standard treatment for lymphangioleiomyomatosis, stabilizes lung function, but all patients do not respond to or tolerate sirolimus. As renin-angiotensin systems may affect tumor growth and metastasis, we questioned if angiotensin-converting enzyme inhibitors affected lymphangioleiomyomatosis disease progression. METHODS. Retrospective study of 426 patients was performed, examining angiotensin-converting enzyme levels, pulmonary function data, and angiotensin-converting enzyme inhibitor treatment. RESULTS. Serum angiotensin-converting enzyme levels were elevated in approximately 33% of patients, increased with duration of disease, and were inversely correlated with pulmonary function. Levels decreased significantly over time with sirolimus treatment. Treatment with angiotensin-converting enzyme inhibitors was reported by approximately 15% of patients and was significantly associated with a slower rate of decline in percentage predicted forced expiratory volume (FEV1) and diffusing capacity of the lungs for carbon monoxide (DLCO) in patients not treated with sirolimus. No significant differences in rates of decline of FEV1 or DLCO were seen in patients treated with both inhibitors and sirolimus versus sirolimus alone. CONCLUSIONS. Angiotensin-converting enzyme inhibitors may slow decline of pulmonary function in patients with lymphangioleiomyomatosis not treated with sirolimus. These inhibitors may be an option or adjunct in the treatment of lymphangioleiomyomatosis. A clinical trial may be warranted to examine this possibility. FUNDING. NIH.
Wendy K. Steagall, Mario Stylianou, Gustavo Pacheco-Rodriguez, Joel Moss
Poly(ADP-ribosyl)ation refers to the covalent attachment of ADP-ribose to protein, generating branched, long chains of ADP-ribose moieties, known as poly(ADP-ribose) (PAR). Poly(ADP-ribose) polymerase 1 (PARP1) is the main polymerase and acceptor of PAR in response to DNA damage. Excessive intracellular PAR accumulation due to PARP1 activation leads cell death in a pathway known as parthanatos. PAR degradation is mainly controlled by poly(ADP-ribose) glycohydrolase (PARG) and ADP-ribose-acceptor hydrolase 3 (ARH3). Our previous results demonstrated that ARH3 confers protection against hydrogen peroxide (H2O2) exposure, by lowering cytosolic and nuclear PAR levels and preventing apoptosis-inducing factor (AIF) nuclear translocation. We identified a family with an ARH3 gene mutation that resulted in a truncated, inactive protein. The 8-year-old proband exhibited a progressive neurodegeneration phenotype. In addition, parthanatos was observed in neurons of the patient’s deceased sibling, and an older sibling exhibited a mild behavioral phenotype. Consistent with the previous findings, the patient’s fibroblasts and ARH3-deficient mice were more sensitive, respectively, to H2O2 stress and cerebral ischemia/reperfusion-induced PAR accumulation and cell death. Further, PARP1 inhibition alleviated cell death and injury resulting from oxidative stress and ischemia/reperfusion. PARP1 inhibitors may attenuate the progression of neurodegeneration in affected patients with ARH3 deficiency.
Masato Mashimo, Xiangning Bu, Kazumasa Aoyama, Jiro Kato, Hiroko Ishiwata-Endo, Linda A. Stevens, Atsushi Kasamatsu, Lynne A. Wolfe, Camilo Toro, David Adams, Thomas Markello, William A. Gahl, Joel Moss
Costimulatory interactions control T cell activation at sites of activated antigen-presenting cells, including B cells. Blockade of the CD28/CD80/CD86 costimulatory axis with CTLA4Ig (abatacept) is widely used to treat certain autoimmune diseases. While transiently effective in subjects with new-onset type 1 diabetes (T1D), abatacept did not induce long-lasting immune tolerance. To elucidate mechanisms limiting immune tolerance in T1D, we performed unbiased analysis of whole blood transcriptomes and targeted measurements of cell subset levels in subjects from a clinical trial of abatacept in new-onset T1D. We showed that individual subjects displayed age-related immune phenotypes (“immunotypes”) at baseline, characterized by elevated levels of B cells or neutrophils, that accompanied rapid or slow progression, respectively, in both abatacept- and placebo-treated groups. A more pronounced immunotype was exhibited by a subset of subjects showing poor response (resistance) to abatacept. This resistance immunotype was characterized by a transient increase in activated B cells (one of the cell types that binds abatacept), reprogrammed costimulatory ligand gene expression, and reduced inhibition of anti-insulin antibodies. Our findings identify immunotypes in T1D subjects that are linked to the rate of disease progression, both in placebo- and abatacept-treated subjects. Furthermore, our results suggest therapeutic approaches to restore immune tolerance in T1D.
Peter S. Linsley, Carla J. Greenbaum, Cate Speake, S. Alice Long, Matthew J. Dufort
Although tyrosine kinase inhibitors (TKIs) have demonstrated significant efficacy in advanced lung adenocarcinoma (LUAD) patients with pathogenic alterations in EGFR, most patients develop acquired resistance to these agents via mechanisms enabling the sustained activation of the PI3K and MAPK oncogenic pathways downstream of EGFR. The tumor suppressor protein phosphatase 2A (PP2A) acts as a negative regulator of these pathways. We hypothesize that activation of PP2A simultaneously inhibits the PI3K and MAPK pathways and represents a promising therapeutic strategy for the treatment of TKI-resistant LUAD. After establishing the efficacy of small molecule activators of PP2A (SMAPs) in a transgenic EGFRL858R model and TKI-sensitive cell lines, we evaluated their therapeutic potential in vitro and in vivo in TKI-resistant models. PP2A activation resulted in apoptosis, significant tumor growth inhibition, and downregulation of PI3K and MAPK pathways. Combination of SMAPs and TKI afatinib resulted in an enhanced effect on the downregulation of the PI3K pathway via degradation of the PP2A endogenous inhibitor CIP2A. An improved effect on tumor growth inhibition was observed in a TKI-resistant xenograft mouse model treated with a combination of both agents. These collective data support the development of PP2A activators for the treatment of TKI-resistant LUAD.
Rita Tohmé, Sudeh Izadmehr, Sai Gandhe, Giancarlo Tabaro, Sanjay Vallabhaneni, Ava Thomas, Neal Vasireddi, Neil S. Dhawan, Avi Ma’ayan, Neelesh Sharma, Matthew D. Galsky, Michael Ohlmeyer, Jaya Sangodkar, Goutham Narla
About one-third of dilated cardiomyopathy (DCM) cases are caused by mutations in sarcomere or cytoskeletal proteins. Yet treating the cytoskeleton directly is not possible because drugs that bind to actin are not well tolerated. Mutations in the actin binding protein CAP2 can cause DCM and knockout mice, either whole body (CAP2 KO) or cardiomyocyte-specific knockouts (CAP2 CKO), develop DCM with cardiac conduction disease. RNA-seq analysis of CAP2 KO hearts and isolated cardiomyocytes revealed over-activation of fetal genes including serum response factor (SRF) regulated genes such as Myl9 and Acta2 prior to the emergence of cardiac disease. To test if we could treat CAP2 KO mice, we synthesized and tested the SRF inhibitor CCG-1423-8u. CCG-1423-8u reduced expression of the SRF targets Myl9 and Acta2, as well as the biomarker of heart failure, Nppa. The median survival of CAP2 CKO mice was 98 days, while CCG-1423-8u treated CKO mice survived for 116 days and also maintain normal cardiac function longer. These results suggest that some forms of sudden cardiac death and cardiac conduction disease are under cytoskeletal stress and that inhibiting signaling through SRF may benefit DCM by reducing cytoskeletal stress.
Yao Xiong, Kenneth C. Bedi, Simon Berritt, Thomas G. Brooks, Bennette K. Attipoe, Kevin Wang, Kenneth B. Margulies, Jeffrey Field
Idiopathic pulmonary fibrosis (IPF) is a progressive disease with unremitting extracellular matrix deposition, leading to a distortion of pulmonary architecture and impaired gas exchange. Fibroblasts from IPF patients acquire an invasive phenotype that is essential for progressive fibrosis. Here, we performed RNA-seq analysis on invasive and non-invasive fibroblasts and found that the immune checkpoint ligand CD274 (PD-L1) was up-regulated on invasive lung fibroblasts and was required for the invasive phenotype of lung fibroblasts, is regulated by P53 and FAK, and drives lung fibrosis in a humanized IPF model in mice. Activating CD274 in IPF fibroblasts promoted invasion in vitro and pulmonary fibrosis in vivo. CD274 knockout in IPF fibroblasts and targeting CD274 by FAK inhibition or CD274 neutralizing antibodies blunted invasion and attenuated fibrosis, suggesting that CD274 may be a novel therapeutic target in IPF.
Yan Geng, Xue Liu, Jiurong Liang, David M. Habiel, Kulur Vrishika, Ana Lucia Coelho, Nan Deng, Ting Xie, Yizhou Wang, Ningshan Liu, Guanling Huang, Adrianne Kurkciyan, Zhenqiu Liu, Jie Tang, Cory M. Hogaboam, Dianhua Jiang, Paul W. Noble
The routes by which antibody-based therapeutics reach malignant cells are poorly defined. Tofacitinib, an FDA-approved JAK inhibitor, reduced tumor-associated inflammatory cells and allowed increased delivery of antibody-based agents to malignant cells. Alone, tofacitinib exhibited no antitumor activity, but combinations with immunotoxins or an antibody drug conjugate resulted in increased anti-tumor responses. Quantification using flow cytometry revealed that antibody-based agents accumulated in malignant cells at higher percentages following tofacitinib treatment. Profiling of tofacitinib-treated tumor-bearing mice indicated that cytokine transcripts and various proteins involved in chemotaxis were reduced compared to vehicle-treated mice. Histological analysis revealed significant changes to the composition of the tumor microenvironment, with reductions in monocytes, macrophages and neutrophils. Tumor-associated inflammatory cells contributed to non-target uptake of antibody-based therapeutics; with mice treated with tofacitinib showing decreased accumulation of therapeutics in intratumoral inflammatory cells and increased delivery to malignant cells. Present findings serve as a rationale for conducting trials where short-term treatments with tofacitinib could be administered in combination with antibody-based therapies.
Nathan Simon, Antonella Antignani, Stephen M. Hewitt, Massimo Gadina, Christine Alewine, David FitzGerald
Tumor radioresistance leading to local therapy failure remains a major obstacle for successful treatment of high-grade glioma. We hypothesized that distinct radiobiological features of particle therapy with carbon ions may circumvent glioma radioresistance. We demonstrate that carbon irradiation (CIR) efficiently eradicates radioresistant patient-derived glioma stem cells (GSCs), leading to growth inhibition and prolonged survival. The impact of CIR at the tumor–stroma interface was further investigated in 2 syngeneic mouse and 2 orthotopic GSC xenograft models. Intriguingly, tumor regressions and long-term local controls were observed at doses greater than or equal to 15-Gy CIR. Fractionated CIR further prolonged survival. The enhanced relative biological effectiveness of CIR in vivo was attributed to its potent antiangiogenic effects and eradication of radioresistant hypoxic tumor cells. Blockade of the HIF1-α/stromal cell–derived factor 1/CXCR4 axis by CIR reduced the recruitment of microglia and myeloid-derived suppressor cells (CD11b+Gr1+). Consequently, CIR abrogated M2-like immune polarization and enhanced the influx of CD8+ cells, generating an immunopermissive niche. We report that radiotherapy with carbon ions could surmount several central glioma resistance mechanisms by eradicating hypoxic and stem cell–like tumor cells, as well as modulating the glioma niche toward an antiangiogenic and less immunosuppressive state. Conclusively, potentially novel rationales for CIR in conquering glioma radioresistance are provided.
Sara Chiblak, Zili Tang, Dieter Lemke, Maximilian Knoll, Ivana Dokic, Rolf Warta, Mahmoud Moustafa, Walter Mier, Stephan Brons, Carmen Rapp, Stefan Muschal, Philipp Seidel, Martin Bendzsus, Sebastian Adeberg, Otmar D. Wiestler, Uwe Haberkorn, Jürgen Debus, Christel Herold-Mende, Wolfgang Wick, Amir Abdollahi
Diarrhea is a major side effect of ErbB receptor tyrosine kinase inhibitors (TKIs) in cancer chemotherapy. Here, we show that the primary mechanism of ErbB TKI diarrhea is activation of basolateral membrane potassium (K+) channels and apical membrane chloride (Cl-) channels in intestinal epithelia, and demonstrate the efficacy of channel blockers in a rat model of TKI diarrhea. Short-circuit current in colonic epithelial cells showed that the TKIs gefitinib, lapatinib and afatinib do not affect basal secretion, but amplify carbachol-stimulated secretion by 2 to 3 fold. Mechanistic studies with the second-generation TKI afatinib showed that the amplifying effect on Cl- secretion was Ca2+ and cAMP independent, blocked by CFTR and K+ channel inhibitors, and involved the EGF receptor binding and ERK signaling. Afatinib-amplified activation of basolateral K+ and apical Cl- channels was demonstrated by selective membrane permeabilization, ion substitution and channel inhibitors. Rats administered afatinib orally at 60 mg/kg/day developed diarrhea with increased stool water from ~60% to >80%, which was reduced by up to 75% the K+ channel inhibitors clotrimazole or senicapoc, or the CFTR inhibitor (R)-BPO-27. These results indicate a mechanism for TKI diarrhea involving K+ and Cl- channel activation, and support the therapeutic efficacy of channel inhibitors.
Tianying Duan, Onur Cil, Jay R. Thiagarajah, Alan S Verkman
Immunotherapies targeting the PD-1 pathway produce durable responses in many cancers, but the tumor-intrinsic factors governing response and resistance are largely unknown. MHC-II expression on tumor cells can predict response to anti–PD-1 therapy. We therefore sought to determine how MHC-II expression by tumor cells promotes PD-1 dependency. Using transcriptional profiling of anti-PD-1–treated patients, we identified unique patterns of immune activation in MHC-II+ tumors. In patients and preclinical models, MHC-II+ tumors recruited CD4+ T cells and developed dependency on PD-1 as well as Lag-3 (an MHC-II inhibitory receptor), which was upregulated in MHC-II+ tumors at acquired resistance to anti–PD-1. Finally, we identify enhanced expression of FCRL6, another MHC-II receptor expressed on NK and T cells, in the microenvironment of MHC-II+ tumors. We ascribe this to what we believe to be a novel inhibitory function of FCRL6 engagement, identifying it as an immunotherapy target. These data suggest a MHC-II–mediated context-dependent mechanism of adaptive resistance to PD-1-targeting immunotherapy.
Douglas B. Johnson, Mellissa J. Nixon, Yu Wang, Daniel Y. Wang, Emily Castellanos, Monica V. Estrada, Paula I. Ericsson-Gonzalez, Candace H. Cote, Roberto Salgado, Violeta Sanchez, Phillip T. Dean, Susan R. Opalenik, Daniel M. Schreeder, David L. Rimm, Ju Young Kim, Jennifer Bordeaux, Sherene Loi, Leora Horn, Melinda E. Sanders, P. Brent Ferrell Jr., Yaomin Xu, Jeffrey A. Sosman, Randall S. Davis, Justin M. Balko
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