No abstract

The enzyme splitting pantethine into pantothenic acid and cystamine has been purified about 3000 times starting from horse kidney. The purification procedure is reported. The enzyme, whose optimal activity lies in the pH range 4.0-5.5, requires the presence of a reduced thiol for the full activity : mercaptoethanol and dithiothreitol give the higher effect. This activation seems not to be specific. The enzyme has a K , value for the substrate of the order of 5 mM and shows inhibition by excess substrate and by products. Substrate specificity studies show that the enzyme splits only the intact substrate molecule, which is not hydrolyzed by several hydrolytic enzymes, even with a broad speci6city (as bacterial pronase and subtilisin). The enzyme could be responsible for the production in vivo of cysteamine, which is known to be oxydized by a specific oxygenase, isolated recently in this laboratory.Identification of an enzyme able of hydrolyzing pantethine t o pantothenic acid and cystaminel has been reported in previous communications from this laboratory [1,2]. The purification of this enzyme is described in this paper. Some characteristic features of the protein and the catalyzed reaction are also presented. The enzyme is named throughout this paper, for our convenience, pantethinase. EXPERIMENTAL PROCEDURE Determination of ProteinThe protein concentration of the starting homogenate was determined by dry weight of samples kept at 110" to constant weight. I n the other steps of purification proteins were determined by the biuret reaction according t o the method of Goa [3].

RationaleAlveolar type II (ATII) cells act as adult stem cells contributing to alveolar type I (ATI) cell renewal and play a major role in idiopathic pulmonary fibrosis (IPF), as supported by familial cases harbouring mutations in genes specifically expressed by these cells. During IPF, ATII cells lose their regenerative potential and aberrantly express pathways contributing to epithelial–mesenchymal transition (EMT). The microRNA miR-200 family is downregulated in IPF, but its effect on human IPF ATII cells remains unproven. We wanted to 1) evaluate the characteristics and transdifferentiating ability of IPF ATII cells, and 2) test whether miR-200 family members can rescue the regenerative potential of fibrotic ATII cells.MethodsATII cells were isolated from control or IPF lungs and cultured in conditions promoting their transdifferentiation into ATI cells. Cells were either phenotypically monitored over time or transfected with miR-200 family members to evaluate the microRNA effect on the expression of transdifferentiation, senescence and EMT markers.ResultsIPF ATII cells show a senescent phenotype (p16 and p21), overexpression of EMT (ZEB1/2) and impaired expression of ATI cell markers (AQP5 and HOPX) after 6 days of culture in differentiating medium. Transfection with certain miR-200 family members (particularly miR-200b-3p and miR-200c-3p) reduced senescence marker expression and restored the ability to transdifferentiate into ATI cells.ConclusionsWe demonstrated that ATII cells from IPF patients express senescence and EMT markers, and display a reduced ability to transdifferentiate into ATI cells. Transfection with certain miR-200 family members rescues this phenotype, reducing senescence and restoring transdifferentiation marker expression.

Abstract. The present study reports two cases of lung cancer with the involvement of the pleura. The diagnosis of adenocarcinoma with epidermal growth factor receptor (EGFR) mutation was made following repeated thoracentesis with cytology of pleural fluid and thoracoscopy with pleural biopsies. Talc pleurodesis was successfully performed in both cases subsequent to diagnosis. Following talc pleurodesis, the first patient (62 years old; male; non-smoker) underwent 3 cycles of cisplatin/vinorelbine chemotherapy, with a poor response. Concurrently, due to the presence of an EGFR mutation, treatment with gefitinib was initiated, with the patient achieving a good response for ~12 months. The residual tumor was treated with stereotactic radiotherapy and the patient continued gefitinib treatment. The patient is presently in good health, has not exhibited any signs of relapse and is continuing gefitinib treatment without side effects. The second patient (53 years old; male ex-smoker) underwent treatment with gefitinib subsequent to talc pleurodesis for a total of 15 months. In addition, radiotherapy (60 Gy) on the residual lesion was performed. Subsequently, second-line therapy with cisplatin/premetrexed was prescribed and followed by maintenance treatment with premetrexed. Three years after diagnosis, the patient did not exhibit any signs of recurrence. These two cases highlight the difficulty in treating advanced stage lung cancer, despite the presence of EGFR mutation. Each lung cancer is different and requires the physician to possess a wide range of knowledge of the therapeutic options available, in addition to careful monitoring in order to adjust the treatment over time. A multidisciplinary approach, involving surgeons, radiation oncologists, pulmonologists and oncologists, is required to optimize the survival and quality of life of patients with lung cancer.

No abstract