Activation of the MEK/ERK Pathway Mediates the Inhibitory Effects of Silvestrol on Nasopharyngeal Carcinoma Cells via RAP1A, HK2, and GADD45A.

BACKGROUND: Nasopharyngeal carcinoma (NPC) is a malignant tumor associated with Epstein-Barr virus (EBV) infection. Chemoradiotherapy is the mainstream treatment for locally advanced NPC, and chemotherapeutic drugs are an indispensable part of NPC treatment. However, the toxic side-effects of chemotherapy drugs limit their therapeutic value, and new chemotherapy drugs are urgently needed for NPC. Silvestrol, an emerging natural plant anticancer molecule, has shown promising antitumor activity in breast cancer, melanoma, liver cancer, and other tumor types by promoting apoptosis in cancer cells to a greater extent than in normal cells. However, the effects of silvestrol on NPC and its possible molecular mechanisms have yet to be fully explored. METHODS: Cell counting kit-8 (CCK-8), cell scratch, flow cytometry, 5-ethynyl-2'-deoxyuridine (EdU), and Western blot (WB) assays were used to evaluate the effects of silvestrol on the cell viability, cell cycle, apoptosis, and migration of NPC cells. RNA sequencing (RNA-Seq) was used to study the effect of extracellular signal-regulated kinase (ERK) inhibitors on the cell transcriptome, and immunohistochemistry (IHC) to assess protein expression levels in patient specimens. RESULTS: Silvestrol inhibited cell migration and DNA replication of NPC cells, while promoting the expression of cleaved caspase-3, apoptosis, and cell cycle arrest. Furthermore, silvestrol altered the level of ERK phosphorylation. The ERK-targeted inhibitor LY3214996 attenuated silvestrol-mediated inhibition of NPC cell proliferation but not migration. Analysis of RNA-Seq data and WB were used to identify and validate the downstream regulatory targets of silvestrol. Expression of GADD45A, RAP1A, and hexokinase-II (HK2) proteins was inhibited by silvestrol and LY3214996. Finally, IHC revealed that GADD45A, RAP1A, and HK2 protein expression was more abundant in cancer tissues than in non-tumor tissues. CONCLUSIONS: Silvestrol inhibits the proliferation of NPC cells by targeting ERK phosphorylation. However, the inhibition of NPC cell migration by silvestrol was independent of the Raf-MEK-ERK pathway. RAP1A, HK2, and GADD45A may be potential targets for the action of silvestrol.

[Evolution of hepatitis B virus quasispecies during lamivudine-entecavir sequential therapy].

OBJECTIVES: To study the evolution of HBV quasispecies under the pressures of lamivudine (LAM) - entecavir (ETV) sequential therapy and its clinical significance. METHODS: Consecutive serum samples from 2 patients underwent LAM-ETV sequential therapy were extensively studied for HBV quasispecies composition and evolution, using PCR-cloning-sequencing method. Maximum likelihood trees were built to analyze the genetic relationship between representative sequences. Correlation between HBV quasispecies evolution and serological/virological data was analyzed to determined the clinical significance of the evolution of HBV quasispecies during prolonged nucleotide analog therapy. RESULTS: Virological breakthrough was observed in both patients. Patient I acquired sustained virological response after switching to ETV rescue therapy, whereas Patient II suffered from virological breakthrough after 72 weeks of ETV therapy. Each virological breakthrough was accompanied with the replacement of previous drug susceptible dominant quasispecies with a drug resistant variant, indicating a close correlation between quasispecies composition and drug susceptibility. The rtL180M+S202G+M204V triple mutant, which was most likely a descendant of the LAM resistant rtL180M+M204V variant, was closely correlated with ETV resistant in Patient II. CONCLUSION: Quasispecies composition of HBV is closely correlated with nucleotide analog susceptibility. ETV resistant variant can emerge from a LAM resistant viral population. Dynamic monitoring of HBV quasispecies composition is of great importance during nucleotide analog therapy.

Antiviral therapy for hepatitis B virus associated hepatic failure.

BACKGROUND: Chronic hepatitis B virus (HBV) infection remains a major global health issue, and the prognosis of patients with HBV-associated fulminant hepatic failure is extremely poor. The application of antiviral therapies has led to significant improvements in patient outcomes. This article aimed to review the current strategies in antiviral treatment of HBV-associated fulminant hepatic failure. DATA SOURCES: Literature search was conducted using PubMed on the related subjects. Part of the data was from the most recent work of the authors' laboratory. RESULTS: Hepatitis B immunoglobulin in prevention of recurrent HBV infection after orthotopic liver transplantation (OLT) has been proven effective. However, its cost is high, and significant side effects have been found to induce viral mutations. Lamivudine has a potent suppression for HBV replication and an excellent safety profile in decompensated cirrhotic patients, but its major drawback is the high rate of drug-resistance. Adefovir is effective for lamivudine-resistance strains in the post-OLT situation, and its drug-resistance rate is relatively low. Combination therapies such as hepatitis B immunoglobulin combined with lamivudine and lamivudine combined with adefovir have been widely adopted for prophylaxis against HBV recurrence of infection after OLT. Entecavir, telbivudine, tenofovir and other newer agents have been widely used in antiviral therapy. CONCLUSIONS: The prognosis of HBV-associated fulminant hepatic failure is being transformed by developments in antiviral therapy. However, it should be noticed that HBV is controlled but never eliminated, and drug-resistance still remains a major issue. Hopefully, newer strategies may help to solve these problems.

[Analysis of the correlation between the pre-S1 antigen, pre-S2 antigen and DNA of hepatitis B virus in the serum of chronic hepatitis B patients undergoing nucleoside analogue therapy.].

OBJECTIVE: To investigate the dynamic correlation between pre-S1 antigen, pre-S2 antigen and HBV DNA in the serum of chronic hepatitis B (CHB) patients undergoing nucleoside analogue therapy. METHODS: 12 CHB patients with transient virological response after lamivudine treatment, and 20 patients treated with adefovir for 5 years were recruited in this study. Serum samples were collected at four time points when HBV DNA fluctuated sharply during lamivudine treatment, and at 0, 8, 12, 28, 52, 104, 156, 208, 260 weeks following adefovir treatment. HBV DNA was quantified by real-time PCR, pre-S1 and pre-S2 antigens were detected by ELISA. RESULTS: The titers of pre-S1 and pre-S2 antigens were not correlated with the HBV DNA level in the serum of lamivudine treated patients. Only in one case of the adfovir treated patients, the decrease of pre-S1 and pre-S2 antigens was in parallel with the decrease of HBV DNA. Linear regression analysis indicated that neither pre-S1 antigen nor pre-S2 antigen was correlated with HBV DNA in the serum of lamivudine or adfovir treated patients (P more than 0.05). CONCLUSION: Our results indicate that the titers of pre-S1 and pre-S2 antigens are not correlated with the serum HBV DNA in CHB patients undergoing nucleoside analogue therapy. Neither pre-S1 nor pre-S2 is a good predictor for the outcome of nucleoside analogue treatment.

Molecular mapping and genetic analysis of a QTL controlling spike formation rate and tiller number in wheat.

Spike formation rate (SR), which is based on maximum tiller number per unit area and spike number per unit area, is an important yield-related trait in wheat. Increasing the spike formation rate reduces growth competition and wastage of photosynthate from ineffective tillers. Unfortunately, research studies involving quantitative trait locus (QTL) mapping for wheat spike formation rate are limited. In the present study, a set of 371 recombinant inbreed line (RIL) population, which were derived from 1BL/LRS wheat-rye translocation lines CN18 and T1208, was analysed by simple sequence repeat (SSR) markers. Genetic analysis showed that a stable and major QTL (QSR.sicau-4D) for spike formation rate was localized to chromosome 4D and explained 18.24% and 24.48% of the observed phenotypic variance in 2015 and 2016, respectively. This QTL was closely linked to SSR marker Xcfd23, and the genetic distance between the flank markers was 3.28cM. Furthermore, QSR.sicau-4D might be a novel pleiotropic QTL, which also controlled maximum tiller number per unit area (QMTN.sicau-4D) and tiller number during pre-winter per unit area (QTNW.sicau-4D). The marker Xcfd23 associated with SR may be utilized in marker-assisted selection in wheat breeding.

Evolutionary pattern of full hepatitis B virus genome during sequential nucleos(t)ide analog therapy.

The evolutionary and mutational pattern of full hepatitis B virus (HBV) quasispecies during sequential nucleos(t)ide analog (NUC) therapy remains unclear. In this study, full-length HBV clones were generated from serial serum samples of five chronic hepatitis B patients who received sequential NUC therapies (treated patients) and two untreated patients with acute flares. The evolutionary and mutational patterns of full HBV quasispecies were studied. In the three treated patients who received lamivudine as initial antiviral therapy, nucleotide polymorphism and nonsynonymous divergence all decreased at lamivudine breakthrough but increased after rescue therapies. Conversely, two other treated patients showed a distinct change in divergence during adefovir-telbivudine sequential therapies. Untreated subjects exhibited increased polymorphism and divergence in the preC/C region at ALT flare. Four of the treated patients presented amino acid changes in the "a" determinant during NUC therapy. All of the treated subjects showed amino acid changes within the known T-cell or B-cell epitopes in the surface or core antigen, most of which were accompanied by mutations in reverse transcriptase (RT) region. Co-variations in the core promoter, the preC region and in the known epitopes of the preS gene accompanied by RT mutations, were common. In untreated patients, most of these co-variations located in the preC/C gene. In conclusion, the distribution of genetic variability of HBV shows remarkably different patterns between the treated and untreated subjects and the quasispecies divergence of different regions of HBV may vary remarkably even within a single host.