Decreased expression of neuregulin1 in the lesional skin of vitiligo patients
INTERNATIONAL JOURNAL OF DERMATOLOGY
Authors: Rani, Seema; Kumari, Uma; Bhardwaj, Supriya; Parsad, Davinder; Sharma, Vijay L.; Kumar, Ravinder
Abstract
Background Paracrine cross-talk exists between the fibroblasts of dermis and epidermal cells through secretions of various growth factors. Melanocytes present at the basement layer of the epidermis and respond to various factors secreted by underlying dermal fibroblasts in the dermis to regulate the function of the skin. Objective Therefore the study was planned to check the expression of fibroblast-derived factor neuregulin1 (NRG1) in vitiligo skin and its effect on melanocytes. Methods For this study, relative gene expression at mRNA level of NRG1 in the vitiligo skin was analyzed by qRT-PCR, and protein analysis was done by immunohistochemistry. Effect of different concentrations of NRG1 was checked on the cultured melanocytes by melanin content assay, proliferation assay, and tyrosinase (TYR) assay. The effect of NRG1 was also checked on the level of melanocyte regulatory genes (MITF, c-KIT, TYR, DCT). Results Expression of NRG1 was significantly less in lesional dermis of vitiligo patients as compared to nonlesional and healthy control dermis both at mRNA as well as protein level. NRG1 treatment showed significant increase in proliferation, melanin content, TYR level, and gene expression level of melanocyte specific genes. Conclusion Treatment of NRG1 to the cultured melanocytes increases proliferation and pigmentation. Lower expression of NRG1 in the lesional dermis of vitiligo patients inhibits the melanocyte growth. Therefore this study hypothesized that low expression of NRG1 in lesional skin of vitiligo patients might have a possible role in the melanocyte loss and vitiligo pathogenesis.
Afatinib reverses ceritinib resistance (CR) in ALK/ROS1-positive non-small-cell lung cancer cell (NSCLC) via suppression of NRG1 pathway
ONCOTARGETS AND THERAPY
Authors: Chen, Hui; Zhang, Qiang; Zhang, Yu; Jia, Bin; Zhang, Bin; Wang, Changli
Abstract
Background: Lung cancer (LC) is the most prevalent malignancy worldwide, and non-small-cell LC (NSCLC) cell is associated with high mortality. As a member of the second generation of anaplastic lymphoma kinase (ALK) suppressors, ceritinib has considerable therapeutic effects for ALK and c-ros oncogene 1 (ROS1)-positive NSCLC cell. Nevertheless, patients inevitably develop resistance to the drug. Our research focused on the exploration of whether afatinib was able to counteract ceritinib resistance (CR) in NSCLC cells with positive ALK or ROS1. Materials and methods: Acquired CR cell sublines (HCC78R and H1299R) were induced by stepwise escalation of ceritinib exposure. MTT assay was used to validate cell proliferation. Fluorescence assay was performed for apoptosis analysis. Quantitative real-time PCR and Western blot assays were used to assess the alterations of signaling pathway-related mRNA and proteins, respectively. Results: We found that prolonged treatment of HCC78 and H1299 with ceritinib brought about 10 times weaker ceritinib sensitivity (CS) in comparison with parent cells. Additionally, the results showed that afatinib efficiently promoted CS, which was evidenced as reduced proliferation and cell death promotion, in NSCLC cells, irrespective of their previous sensitivity or resistance to ceritinib. Moreover, afatinib decreased neuregulin-1 (NRG1) signaling stimulation in CR as well as CS cells. Furthermore, supplementing NRG1 in H1299 and HCC78 cells triggered CR, which was attenuated by afatinib. Conclusion: These results demonstrated that afatinib overcame CR in NSCLC cells with positive ALK or ROS1 by inhibiting the NRG1 signaling pathway, which might be a promising therapeutic approach.