ABSTRACT
Necroptosis is an alternative form of programmed cell death that generally occurs under apoptosis-deficient conditions. Our previous work showed that connexin32 (Cx32) promotes the malignant progress of hepatocellular carcinoma (HCC) by enhancing the ability of resisting apoptosis in vivo and in vitro. Whether triggering necroptosis is a promising strategy to eliminate the apoptosis-resistant HCC cells with high Cx32 expression remains unknown. In this study, we found that Cx32 expression was positively correlated with the expression of necroptosis protein biomarkers in human HCC specimens, cell lines, and a xenograft model. Treatment with shikonin, a well-used necroptosis inducer, markedly caused necroptosis in HCC cells. Interestingly, overexpressed Cx32 exacerbated shikonin-induced necroptosis, but downregulation of Cx32 alleviated necroptosis in vitro and in vivo. Mechanistically, Cx32 was found to bind to Src and promote Src-mediated caspase 8 phosphorylation and inactivation, which ultimately reduced the activated caspase 8-mediated proteolysis of receptor-interacting serine-threonine protein kinase 1/3, the key molecule for necroptosis activation. In conclusion, we showed that Cx32 contributed to the activation of necroptosis in HCC cells through binding to Src and then mediating the inactivation of caspase 8. The present study suggested that necroptosis inducers could be more favorable than apoptosis inducers to eliminate HCC cells with high expression of Cx32.
Subject(s)
Carcinoma, Hepatocellular/metabolism , Caspase 8/metabolism , Connexins/metabolism , Liver Neoplasms/metabolism , Necroptosis/genetics , Nuclear Receptor Coactivator 1/metabolism , Signal Transduction/genetics , Animals , Apoptosis/drug effects , Apoptosis/genetics , Carcinoma, Hepatocellular/genetics , Carcinoma, Hepatocellular/pathology , Cell Line, Tumor , Cell Proliferation/drug effects , Cell Proliferation/genetics , Connexins/genetics , Gene Knockdown Techniques , Humans , Liver Neoplasms/genetics , Liver Neoplasms/pathology , Male , Mice , Mice, Inbred BALB C , Mice, Nude , Naphthoquinones/administration & dosage , Necroptosis/drug effects , Nuclear Receptor Coactivator 1/genetics , Phosphorylation/drug effects , Phosphorylation/genetics , Signal Transduction/drug effects , Transfection , Tumor Burden/drug effects , Tumor Burden/genetics , Gap Junction beta-1 ProteinABSTRACT
OBJECTIVE: To investigate Epstein-Barr virus(EBV) infection in Hodgkin's lymphoma (HL) of Uygur patients and related clinicopathological characteristics. METHODS: EBV-encoded small RNA (EBER) was detected in 40 cases of HL and 20 cases of lymphoid reactive hyperplasia by in-situ hybridization. Expression of LMP2A in HL was investigated by immunohistochemistry. RESULTS: EBV was detected in 26/40 (65.0%) of HL and 5/20 of lymphoid reactive hyperplasia (P < 0.05). The expression level of EBER showed significant difference among various histological subtypes of HL (P < 0.05) and between patients with and without B symptom (P = 0.02). However, no difference was found in relation to gender, clinical stage and tumor burden. The expression of LMP2A in the mixed cellularity and nodular sclerosis classical HL associated with EBV infection was 57.7% (15/26). Expression of LMP2A was not detected in lymphoid reactive hyperplasia cases. CONCLUSION: Uyghur patients with Hodgkin's lymphoma have a high infection rate of EBV and distinct clinicopathologic characteristics.
Subject(s)
Epstein-Barr Virus Infections , Herpesvirus 4, Human , Hodgkin Disease , Viral Matrix Proteins/metabolism , Adolescent , Adult , Child , Child, Preschool , China/ethnology , Female , Herpesvirus 4, Human/isolation & purification , Hodgkin Disease/metabolism , Hodgkin Disease/pathology , Hodgkin Disease/virology , Humans , Immunohistochemistry , In Situ Hybridization , Lymphatic Metastasis , Male , Middle Aged , Pseudolymphoma/metabolism , Pseudolymphoma/pathology , Pseudolymphoma/virology , RNA, Viral/metabolism , Young AdultABSTRACT
OBJECTIVE: To investigate the relationship between plasma EBV-DNA concentration and clinicopathologic features of Hodgkin's lymphoma cases. METHODS: At first, the positive rate of plasma EBV-DNA was determined with a nested-PCR method using 45 specimens from Uygur HL patients, as well as 110 healthy people sampled as normal controls. Secondly, using fluorescent quantitative nested-PCR, EBV viral load was assessed in the EBV-DNA positive plasma samples. Then, relationships between plasma EBV viral load and clinicopathologic features of HL patients were analyzed. RESULTS: The positive rate of plasma EBV-DNA of HL patients was significantly higher than that of normal controls (53.3%vs26.4%, P=0.001). There was no significant difference about plasma EBV viral load between EBV-associated HL and EBV-DNA positive normal people (P=0.490). Looking at patients' characteristics, plasma EBV viral load in 10-20 years EBV-associated HL was higher than in EBV cases which were less than 10 years or more than 35 years (P=0.025). Furthermore, in EBV-associated HL, concentration of plasma EBV-DNA was significantly higher in advanced stage disease (stages III-IV; P=0.013), and with B-symptoms (P=0.020). CONCLUSION: EBV-DNA levels were associated with part of clinicopathologic features of cases. It was of practical use to screen HL. Further etiological studies appear warranted.