ABSTRACT
Lung cancer is the leading cause of cancer mortality worldwide and KRAS is the most commonly mutated gene in lung adenocarcinoma (LUAD). The 78-kDa glucose-regulated protein GRP78/BiP is a key endoplasmic reticulum chaperone protein and a major pro-survival effector of the unfolded protein response (UPR). Analysis of the Cancer Genome Atlas database and immunostain of patient tissues revealed that compared to normal lung, GRP78 expression is generally elevated in human lung cancers, including tumors bearing the KRASG12D mutation. To test the requirement of GRP78 in human lung oncogenesis, we generated mouse models containing floxed Grp78 and Kras Lox-Stop-Lox G12D (KrasLSL-G12D) alleles. Simultaneous activation of the KrasG12D allele and knockout of the Grp78 alleles were achieved in the whole lung or selectively in lung alveolar epithelial type 2 cells known to be precursors for adenomas that progress to LUAD. Here we report that GRP78 haploinsufficiency is sufficient to suppress KrasG12D-mediated lung tumor progression and prolong survival. Furthermore, GRP78 knockdown in human lung cancer cell line A427 (KrasG12D/+) leads to activation of UPR and apoptotic markers and loss of cell viability. Our studies provide evidence that targeting GRP78 represents a novel therapeutic approach to suppress mutant KRAS-mediated lung tumorigenesis.
Subject(s)
Endoplasmic Reticulum Chaperone BiP/metabolism , Lung Neoplasms/pathology , Mutation , Proto-Oncogene Proteins p21(ras)/genetics , Unfolded Protein Response , Animals , Cell Line, Tumor , Disease Models, Animal , Disease Progression , Endoplasmic Reticulum Chaperone BiP/genetics , Humans , Lung Neoplasms/genetics , Lung Neoplasms/metabolism , Mice , Mice, Knockout , Mice, Transgenic , Signal TransductionABSTRACT
This article contains experimental data examining the propensity of neuronal ELAVL proteins to become isoaspartylated. The data are related to the article "Isoaspartylation appears to trigger small cell lung cancer-associated autoimmunity against neuronal protein ELAVL4" (M.A. Pulido, M.K. DerHartunian, Z. Qin, E.M. Chung, D.S. Kang, A.W. Woodham, J.A. Tsou, R. Klooster, O. Akbari, L. Wang, W.M. Kast, S.V. Liu, J.J.G.M. Verschuuren, D.W. Aswad, I.A. Laird-Offringa, 2016) [1], in which it was reported that the N-terminal region of recombinant human ELAVL4 protein, incubated under physiological conditions, acquires a type of highly immunogenic protein damage. Here, we present Western blot analysis data generated by using an affinity-purified polyclonal rabbit antibody (raised against an N-terminal ELAVL4 isoaspartyl-converted peptide) to probe recombinant protein fragments of the other three members of the ELAVL family: the highly homologous neuronal ELAVL2 (HuB) and ELAVL3 (HuC), and the much less homologous ubiquitously expressed ELAVL1 (HuR).
ABSTRACT
Autoantibodies against SCLC-associated neuronal antigen ELAVL4 (HuD) have been linked to smaller tumors and improved survival, but the antigenic epitope and mechanism of autoimmunity have never been solved. We report that recombinant human ELAVL4 protein incubated under physiological conditions acquires isoaspartylation, a type of immunogenic protein damage. Specifically, the N-terminal region of ELAVL4, previously implicated in SCLC-associated autoimmunity, undergoes isoaspartylation in vitro, is recognized by sera from anti-ELAVL4 positive SCLC patients and is highly immunogenic in subcutaneously injected mice and in vitro stimulated human lymphocytes. Our data suggest that isoaspartylated ELAVL4 is the trigger for the SCLC-associated anti-ELAVL4 autoimmune response.
Subject(s)
Autoimmunity/immunology , ELAV-Like Protein 4/immunology , Lung Neoplasms/immunology , Neurons/immunology , Small Cell Lung Carcinoma/immunology , Adult , Aged , Amino Acid Sequence , Animals , ELAV-Like Protein 4/genetics , ELAV-Like Protein 4/metabolism , Female , Humans , Lung Neoplasms/genetics , Lung Neoplasms/metabolism , Male , Mice , Mice, Knockout , Middle Aged , Neurons/metabolism , Rabbits , Small Cell Lung Carcinoma/genetics , Small Cell Lung Carcinoma/metabolismABSTRACT
The behavior and composition of coronary atherosclerotic plaques are ultimately responsible for the threat of acute ischemic events in patients with coronary artery disease. Different imaging modalities have been developed over the last several years in order to better characterize the atherosclerotic plaque and attempt to predict those in peril of complication. Since its implementation into cardiovascular medicine, nearly 40 years ago, coronary angiography has been the mainstay of identifying hemodynamically stenotic lesions. Further investigation into imaging modalities have suggested, however, that the degree of stenosis is only one of several factors influencing a plaque's tendency to rupture. Recent advances in imaging modalities, including invasive and non-invasive studies, have allowed us to examine the histological components that comprise these plaques. Specific information such as variations in temperature, plaque stiffness and calcification level is currently being researched as well as biological and chemical markers. The ultimate goal is to visualize the plaque and its characteristics, stratify its risk for acute events, be able to apply this modality to the general population of cardiac patients, while exposing the patient to minimal risk and having adequate positive and negative predictive values. This manuscript will review the more recent data concerning these interventions and their individual characteristics.
