calpain and Epstein-Barr-Virus-Infections

Capn4, also known as CapnS1, is a member of the calpain family, which plays a crucial role in maintaining the activity and function of calpain. We previously reported that Capn4 also plays an essential role in the migration of nasopharyngeal carcinoma (NPC) cells through regulation of (MMP-2) by nuclear factor-kappa B activation. Epstein-Barr virus latent membrane protein 1 (LMP1) is closely related to the malignant functions of NPC; however, the relationship between LMP1 and Capn4 in NPC remain unclear. Immunohistochemical studies showed that the level of LMP1 and Capn4 expression was high in both primary and metastatic NPC tissues, with a significantly positive correlation. We further found that LMP1 was able to upregulate the Capn4 promoter in a dose-dependent way through the C-terminal activation region (CTAR)1 and CTAR2 domains to activate AP-1. Moreover, we also found that LMP1 activated AP-1 through ERK/JNK phosphorylation. These findings indicate that Capn4 coordination with LMP1 promotes actin rearrangement and, ultimately, cellular migration. These results show that Capn4 coordination with LMP1 enhances NPC migration by increasing actin rearrangement involving ERK/JNK/AP-1 signaling. Therapeutically, additional and more specific LMP1 and Capn4 targeted inhibitors could be exploited to treat NPC.

Topics: Calpain; Cell Line, Tumor; Epstein-Barr Virus Infections; Gene Expression Regulation, Neoplastic; Herpesvirus 4, Human; Humans; MAP Kinase Signaling System; Nasopharyngeal Carcinoma; Nasopharyngeal Neoplasms; Neoplasm Metastasis; NF-kappa B; Phosphorylation; Promoter Regions, Genetic; Signal Transduction; Transcription Factor AP-1; Up-Regulation; Viral Matrix Proteins

Calpain small subunit 1 (Capn4) plays a key role in tumor migration or invasion. In this study, expression and function of Capn4 was investigated in human nasopharyngeal carcinoma (NPC). Here we report that both mRNA and protein levels of Capn4 were elevated in NPC tissues when compared to normal NP tissues. Similarly, Capn4 was also highly expressed in multiple NPC cell lines, compared to immortalized human nasopharyngeal epithelial cell line NP69. Moreover, expression of Capn4 was significantly correlated with Epstein-Barr virus infection, advanced stages, and lymph node or distant metastasis (P < 0.001). The patients with NPC displaying higher Capn4 had a significantly shorter overall survival (P = 0.002) and progression-free survival (P = 0.003). Furthermore, siRNA knockdown of Capn4 suppressed cell migration and invasion in vitro and in vivo. These events resulted from Capn4 downregulation were associated with reduced expression of matrix metalloproteinase 2 (MMP2), Snail, and Vimentin. Finally, we demonstrated that Capn4 upregulated MMP2 via nuclear factor-κB (NF-κB) activation, manifested by increased phosphorylation of p65, a subunit of NF-κB. Together, these findings argue a novel function of Capn4 in invasion and metastasis of NPC, and thereby suggest that Capn4 may represent an independent prognostic factor and a potential therapeutic target in NPC.

Topics: Animals; Biomarkers, Tumor; Cadherins; Calpain; Carcinoma; Cell Line, Tumor; Cell Movement; Disease-Free Survival; Enzyme Activation; Epstein-Barr Virus Infections; Female; Focal Adhesions; Gene Expression Regulation, Neoplastic; Humans; Male; Matrix Metalloproteinase 2; Mice; Mice, Inbred BALB C; Mice, Nude; Middle Aged; Nasopharyngeal Carcinoma; Nasopharyngeal Neoplasms; Neoplasm Invasiveness; Neoplasm Metastasis; Phosphorylation; RNA Interference; RNA, Messenger; RNA, Small Interfering; Snail Family Transcription Factors; Transcription Factor RelA; Transcription Factors; Vimentin

Against the background of its earliest recognition, programmed cell death (PCD) or apoptosis (A) is presented in its fundamental biological contexts. Techniques of its demonstration are listed. Former original works of the authors encompass designs for genetically engineered oncolytic viruses. Presented here are observations on mesenchymal stromal cells of the bone marrow serving as feeder layers to chronic lymphocytic leukemia (CLL) cells (recently rediscovered elsewhere as subverted "nurse cells" protecting CLL cells from A). A-resistant human melanoma cells are shown to expropriate the Fas ligand to Fas receptor (CD95; APO-1) (FasL-->FasR) system for their autocrine growth loop not only in melanoma cells coexpressing CD95 and its ligand but also in CD95-positive melanoma cells undergoing divisions when exposed to CD95 ligand. Bi-directional A-induction is demonstrated upon the encounter of cytotoxic lymphocytes and targeted tumor cells as exemplified with lymphomas; and chemotherapy-induced A of malignant cells as exemplified by paclitaxel-induced PCD of Reed-Sternberg (RS) cells in a case of chemotherapy-resistant Hodgkin's disease (HD). A list of interventions capable of inducing A in tumor cells is provided. These interventions are of potential therapeutic value. The balance of apoptotic and anti-apoptotic forces in virally infected normal and malignant cells is discussed.

Topics: Adenosine Triphosphate; Antineoplastic Combined Chemotherapy Protocols; Apoptosis; Bone Marrow; Calpain; Caspases; Cell Division; Cell Membrane; Epstein-Barr Virus Infections; Fas Ligand Protein; fas Receptor; Female; Hodgkin Disease; Humans; Male; Membrane Glycoproteins; Mitochondria; Neoplasms; T-Lymphocytes, Cytotoxic; Tumor Cells, Cultured; Vesicular stomatitis Indiana virus