cyclin-d1 and Lung-Diseases--Interstitial

Distinction of idiopathic pulmonary fibrosis (IPF) from other chronic fibrosing interstitial pneumonitides, such as hypersensitivity pneumonitis (HP) and connective tissue diseases, is critical due to varied biological and clinical outcomes. However, their histologic overlaps often pose diagnostic challenges. A recent study suggested an association of herpesvirus saimiri infection with IPF. Productive viral infection is associated with coexpression of pirated mammalian protein cyclin D1, shown to be overexpressed by immunohistochemistry (IHC) in the regenerating alveolar epithelium in IPF but not in normal lungs. We evaluated the diagnostic utility of cyclin D1 to discriminate between IPF and other fibrosing interstitial lung diseases.. A retrospective study of cyclin D1 IHC expression in 27 consecutive cases of chronic fibrosing interstitial lung diseases from 2011 to 2017: 12 usual interstitial pneumonia (UIP) pattern; 5 nonspecific interstitial pneumonia pattern; 3 HP pattern; 7 unclassifiable was performed. Five cases of normal lung obtained from lobectomy specimen for malignancy are included as control. Immunoreactivity was graded semiquantitatively on a scale of 0 to 3.. Cyclin D1 staining was uniformly strongly positive in all cases evaluated in the study, particularly in proliferating type II pneumocytes in the region of fibrosing areas. There was no statistical difference in the extent of cyclin D1 expression between UIP and non-UIP groups (2.7 vs. 2.5) and IPF versus non-IPF groups (2.7 vs. 2.4). Cyclin D1 expression is lower in control group compared with UIP groups (1.2 vs. 2.7).. Cyclin D1 is not a specific marker of UIP pattern/IPF. The high expression of cyclin D1 in lung tissue of fibrosing interstitial pneumonitides regardless of etiology most likely correlates with proliferation in type II pneumocytes.

Topics: Adult; Aged; Biomarkers; Cyclin D1; Diagnosis, Differential; Female; Herpesviridae Infections; Herpesvirus 2, Saimiriine; Humans; Idiopathic Pulmonary Fibrosis; Immunohistochemistry; Lung; Lung Diseases, Interstitial; Male; Middle Aged; Retrospective Studies; Tumor Virus Infections; Up-Regulation

The lung alveoli slowly self-renew pneumocytes, but their facultative regeneration capacity is rapidly efficient after an injury, so fibrosis infrequently occurs. We recently observed Keratin 14 (KRT14) expression during diffuse alveolar damage (DAD), but not in controls. We wonder if KRT14 may be a marker of pneumocyte transition from quiescence to regeneration. Quantitative PCR and Western blot analyses highlighted the presence of KRT14 (mRNA and protein) only in human lung samples with DAD or interstitial lung disease (ILD). In the exponentially growing cell lines A549 and H441, the mRNA and protein levels of KRT14 peaked at day one after cell seeding and decreased at day two, opposite to what observed for the proliferation marker E2F1. The inverse relation of KRT14 versus E2F1 expression holds true also for other proliferative markers, such as cyclin E1 and cyclin D1. Of interest, we also found that E2F1 silencing caused cell cycle arrest and increased KRT14 expression, whilst E2F1 stimulation induced cell cycle progression and decreased KRT14. KRT14 also increased in proliferative pneumocytes (HPAEpiC) just before transdifferentiation. Overall, our results suggest that KRT14 is a viable biomarker of pneumocyte activation, and repair/regeneration. The involvement of KRT14 in regenerative process may suggest a novel pharmaceutical target to accelerate lung repair.

Topics: A549 Cells; Adolescent; Aged; Aged, 80 and over; Alveolar Epithelial Cells; Cell Cycle Checkpoints; Cell Proliferation; Cell Transdifferentiation; Cells, Cultured; Cyclin D1; Cyclin E; E2F1 Transcription Factor; Female; Humans; Keratin-14; Lung Diseases, Interstitial; Male; Middle Aged; Oncogene Proteins; RNA Interference; RNA, Messenger; RNA, Small Interfering; Transcriptome

Gefitinib and erlotinib are anticancer agents, which inhibit epidermal growth factor receptor (EGFR) tyrosine kinase. Interstitial lung disease (ILD) occurs in patients with non-small cell lung cancer receiving EGFR inhibitors. In the present study, we examined whether gefitinib- and erlotinib-induced lung injury related to ILD through endoplasmic reticulum (ER) stress, which is a causative intracellular mechanism in cytotoxicity caused by various chemicals in adenocarcinomic human alveolar basal epithelial cells. These two EGFR inhibitors increased Parkinson juvenile disease protein 2 and C/EBP homologous protein mRNA expressions, and activated the eukaryotic initiation factor (eIF) 2α/activating transcription factor 4 pathway without protein kinase R-like ER kinase activation in A549 cells. Gefitinib and erlotinib caused neither ER stress nor cell death; however, these agents inhibited cell growth via the reduction of cyclin-D1 expression. Tauroursodeoxycholic acid, which is known to suppress eIF2α phosphorylation, cancelled the effects of EGFR inhibitors on cyclin-D1 expression and cell proliferation in a concentration-dependent manner. The results of an EGFR-silencing study using siRNA showed that gefitinib and erlotinib affected eIF2α phosphorylation and cyclin-D1 expression independent of EGFR inhibition. Therefore, the inhibition of cell growth by these EGFR inhibitors might equate to impairment of the alveolar epithelial cell repair system via eIF2α phosphorylation and reduced cyclin-D1 expression.

Topics: Antineoplastic Agents; Cell Line; Cell Proliferation; Cyclin D1; Endoplasmic Reticulum Stress; ErbB Receptors; Erlotinib Hydrochloride; Eukaryotic Initiation Factor-2; Gefitinib; Humans; Lung Diseases, Interstitial; Phosphorylation; Pulmonary Alveoli; Quinazolines; Signal Transduction; Taurochenodeoxycholic Acid