Significant predictors of overall survival in patients with hepatocellular carcinoma after surgical resection.

BACKGROUND: The predictive factors of overall survival after hepatectomy for HCC remain controversial and need to be investigated. METHODS: In total, 535 consecutive HCC patients undergoing resection were included and their clinicopathological data and overall survival were recorded. Both the tumor and adjacent non-tumor (ANT) tissues were subjected to immunohistochemistry analysis for the expression of autophagy-related markers. RESULTS: Death was observed for 219 patients, and the cumulative overall survival rates at 1, 3, 5 and 7 years were 91.0%, 72.3%, 58.8%, and 27.7%, respectively. In the multivariate analysis, mortality was significantly associated with the following: diminished LC3 expression in both the tumor and ANT tissues, in the HCC tissues alone and in the ANT tissues alone (hazard ratio/95% confidence interval: 6.74/2.052-22.19, 6.70/1.321-33.98 and 2.58/1.499-4.915, respectively); recurrent HCC (5.11/3.136-8.342); HBV infection (2.75/1.574-4.784); cirrhosis (1.78/1.059-2.974); and antiviral therapy (0.42/0.250-0.697). The 5-year overall survival rates were 70.2%, 57.3%, 49.6% and 10.7% for patients with positive LC3 expression in both tissue types, in the HCC tissues alone, in the ANT tissues alone, and in neither tissue type, respectively. The 5-year overall survival rates were 56.7%, 47.3%, 51.2% and 38.7% for patients with HBV-related HCC, cirrhosis, no antiviral therapy, and recurrent HCC, respectively, and these rates were significantly lower than those in their counterparts. CONCLUSIONS: Patients with recurrent HCC, HBV-related HCC, cirrhosis, and the absence of antiviral therapy showed significantly lower overall survival rates. Furthermore, LC3 expression in both the tumor and liver microenvironments were significantly predictive of overall survival after resection for HCC.

Autophagy-related gene LC3 expression in tumor and liver microenvironments significantly predicts recurrence of hepatocellular carcinoma after surgical resection.

BACKGROUND: The role of autophagy-related markers as the prognostic factor of post-operative hepatocellular carcinoma (HCC) recurrence remained controversial. METHODS: Overall, 535 consecutive HCC patients undergoing curative resection from 2010 to 2014 were followed and classified with early (ER, <2 years) or late recurrence (LR). Autophagy-related markers, LC3, Beclin-1, and p62 expression was immunohistochemically assessed in HCC and adjacent non-tumor (ANT) tissues. RESULTS: HCC recurred in 245 patients: 116 with ER and 129 with LR. The cumulative incidence of recurrence at 1, 3, 5, and 7 years was 9.7%, 33.9%, 53.3%, and 66.3%, respectively. In multivariate analysis, HCC recurrence was significantly associated with low LC3 expression in tumor and ANT tissues, HCC tissues only and ANT tissues only (hazard ratio/95% confidence interval: 6.12/2.473-17.53, 4.18/1.285-13.61, and 1.89/1.299-2.757) and macrovascular invasion (1.63/1.043-2.492) and cirrhosis (1.59/1.088-2.326). ER was significantly associated with low LC3 expression in tumor and ANT tissues, HCC tissues only and ANT tissues only (6.54/2.934-15.81, 3.26/1.034-10.27, and 2.09/1.313-3.321) and macrovascular and microvascular invasion (2.65/1.306-5.343 and 2.55/1.177-5.504). LR was significantly associated with low LC3 expression in tumor and ANT tissues, HCC tissues only and ANT tissues only (5.02/1.372-18.83, 3.19/1.13-12.09, and 1.66/1.051-2.620) and cirrhosis (1.66/1.049-2.631). Patients with low and high LC3 expression in tumor and ANT tissues showed a 5-year cumulative recurrence of 94.3% and 41.7%, respectively (p < 0.001). CONCLUSIONS: The high LC3 expression in the tumor and liver microenvironments is significantly associated with lower HCC recurrence. Furthermore, tumor characteristics and liver microenvironment were also significantly associated with ER and LR, respectively. TRANSLATIONAL IMPACT: The analysis for LC3 expression in both the HCC and ANT tissues could identify patients at risk of HCC recurrence.

Phalaenopsis flowering locus VE regulates floral organ maturation.

KEY MESSAGE: PaFVE is low ambient temperature-inducible and acts as a systemic regulator in the early stage of floral development in Phalaenopsis. Phalaenopsis aphrodite: subsp. formosana, a native orchid species of Taiwan, is an economically important ornamental crop that requires low ambient temperature for floral transition. Currently, limited genetic information about such orchid species hampers genetic manipulation for specific or improved floral traits, and the control of flowering time independent of temperature regulation. In this study, the sequence of the full-length of Phalaenopsis flowering locus VE (PaFVE) gene was determined. Spatial and temporal expression studies showed that mRNA transcripts of PaFVE were inducible by low ambient temperature, and high levels of expression occurred after spiking initiation and remained high throughout the early stage of floral development. Further investigation revealed that floral organ development was impeded in PaFVE-silenced P. aphrodite, but flowering time and floral organogenesis were not compromised. Analysis of the downstream flowering genes suggested that the delay in floral maturation is associated with a corresponding decrease in the expression of downstream flowering genes, PaSOC1, PaSOC1L and PaAGL24. The ectopic expression of PaFVE in Arabidopsis resulted in an accelerated flowering time, accompanied by an increase in the expression of AtSOC1, thus revealing the functional role of PaFVE as a floral regulator. Overall, our results demonstrate that PaFVE has evolutionarily diverged and conserved functions, and serves as a regulator of floral organ maturation in Phalaenopsis and a regulator of flowering time in Arabidopsis.

The autophagy marker LC3 strongly predicts immediate mortality after surgical resection for hepatocellular carcinoma.

The remnant liver's ability to regenerate may affect post-hepatectomy immediate mortality. The promotion of autophagy post-hepatectomy could enhance liver regeneration and reduce mortality. This study aimed to identify predictive factors of immediate mortality after surgical resection for hepatocellular carcinoma (HCC). A total of 535 consecutive HCC patients who had undergone their first surgical resection in Taiwan were enrolled between 2010 and 2014. Clinicopathological data and immediate mortality, defined as all cause-mortality within three months after surgery, were analyzed. The expression of autophagy proteins (LC3, Beclin-1, and p62) in adjacent non-tumor tissues was scored by immunohistochemical staining. Approximately 5% of patients had immediate mortality after surgery. The absence of LC3, hypoalbuminemia (<3.5 g/dl), high alanine aminotransferase, and major liver surgery were significantly associated with immediate mortality in univariate analyses. Multivariate logistic regression demonstrated that absence of LC3 (hazard ratio/95% confidence interval: 40.8/5.14-325) and hypoalbuminemia (2.88/1.11-7.52) were significantly associated with immediate mortality. The 3-month cumulative incidence of mortality was 12.1%, 13.0%, 21.4% and 0.4%, respectively, among patients with absence of LC3 expression, hypoalbuminemia, both, or neither of the two. In conclusion, the absence of LC3 expression in adjacent non-tumor tissues and hypoalbuminemia were strongly predictive of immediate mortality after resection for HCC.

The Arabidopsis defensin gene, AtPDF1.1, mediates defence against Pectobacterium carotovorum subsp. carotovorum via an iron-withholding defence system.

Plant defensins (PDFs) are cysteine-rich peptides that have a range of biological functions, including defence against fungal pathogens. However, little is known about their role in defence against bacteria. In this study, we showed that the protein encoded by ARABIDOPSIS THALIANA PLANT DEFENSIN TYPE 1.1 (AtPDF1.1) is a secreted protein that can chelate apoplastic iron. Transcripts of AtPDF1.1 were induced in both systemic non-infected leaves of Arabidopsis thaliana plants and those infected with the necrotrophic bacterium Pectobacterium carotovorum subsp. carotovorum (Pcc). The expression levels of AtPDF1.1 with correct subcellular localization in transgenic A. thaliana plants were positively correlated with tolerance to Pcc, suggesting its involvement in the defence against this bacterium. Expression analysis of genes associated with iron homeostasis/deficiency and hormone signalling indicated that the increased sequestration of iron by apoplastic AtPDF1.1 overexpression perturbs iron homeostasis in leaves and consequently activates an iron-deficiency-mediated response in roots via the ethylene signalling pathway. This in turn triggers ethylene-mediated signalling in systemic leaves, which is involved in suppressing the infection of necrotrophic pathogens. These findings provide new insight into the key functions of plant defensins in limiting the infection by the necrotrophic bacterium Pcc via an iron-deficiency-mediated defence response.

Virus resistance in orchids.

Orchid plants, Phalaenopsis and Dendrobium in particular, are commercially valuable ornamental plants sold worldwide. Unfortunately, orchid plants are highly susceptible to viral infection by Cymbidium mosaic virus (CymMV) and Odotoglossum ringspot virus (ORSV), posing a major threat and serious economic loss to the orchid industry worldwide. A major challenge is to generate an effective method to overcome plant viral infection. With the development of optimized orchid transformation biotechnological techniques and the establishment of concepts of pathogen-derived resistance (PDR), the generation of plants resistant to viral infection has been achieved. The PDR concept involves introducing genes that is(are) derived from the virus into the host plant to induce RNA- or protein-mediated resistance. We here review the fundamental mechanism of the PDR concept, and illustrate its application in protecting against viral infection of orchid plants.

MSRB7 reverses oxidation of GSTF2/3 to confer tolerance of Arabidopsis thaliana to oxidative stress.

Methionine sulfoxide reductases (MSRs) catalyse the reduction of oxidized methionine residues, thereby protecting proteins against oxidative stress. Accordingly, MSRs have been associated with stress responses, disease, and senescence in a taxonomically diverse array of organisms. However, the cytosolic substrates of MSRs in plants remain largely unknown. Here, we used a proteomic analysis strategy to identify MSRB7 substrates. We showed that two glutathione transferases (GSTs), GSTF2 and GSTF3, had fewer oxidized methionine (MetO) residues in MSRB7-overexpressing Arabidopsis thaliana plants than in wild-type plants. Conversely, GSTF2 and GSTF3 were highly oxidized and unstable in MSRB7-knockdown plants. MSRB7 was able to restore the MetO-GSTF2M100/104 and MetO-GSTF3M100 residues produced during oxidative stress. Furthermore, both GSTs were specifically induced by the oxidative stress inducer, methyl viologen. Our results indicate that specific GSTs are substrates of MSRs, which together provide a major line of defence against oxidative stress in A. thaliana.

Strong antibody responses to Mycobacterium tuberculosis PE-PGRS62 protein are associated with latent and active tuberculosis.

Mycobacterium tuberculosis has a unique family of PE-PGRS proteins with conserved N-terminal domains (PE) containing site-specific proline-glutamine residues and polymorphic GC-rich repetitive sequences (PGRS). Tuberculosis (TB) patients produce antibodies against some such proteins, but it is not clear whether these responses correlate with disease. Clinical groups with different mycobacterium exposure were studied for their seroreactivity to PE-PGRS17 and PE-PGRS62 proteins and their respective PE domains. There were minimal antibody responses against both PE domains and full-length PE-PGRS17, even in patients with active TB. However, patients with active and latent TB showed significantly higher PE-PGRS62-specific immunoglobulin G antibody responses than treated TB patients and mycobacterium-reactive TB contacts without latent infection. Latently infected persons had high anti-PE-PGRS62 responses but low responses to the 38-kDa antigen commonly used for TB serology, while treated TB cases showed the opposite response. Thus, patterns of seroreactivity to PE-PGRS62 correlate with clinical status and are associated with latent TB infection.

Degradation-resistant protein domains limit host cell processing and immune detection of mycobacteria.

The Mycobacterium tuberculosis genome reveals a large family of glycine-alanine rich PE-PGRS proteins. Due to similarities with the glycine-alanine rich Epstein-Barr nuclear antigen 1, there has been interest in whether PE-PGRS proteins inhibit cellular processing and presentation via the major histocompatibility complex class I pathway. We investigated whether PE-PGRS proteins were resistant to ubiquitin-proteasome-dependent degradation and CD8(+) T cell recognition. Upon transient expression of ubiquitin fusion constructs of either full-length Rv0978c(PE-PGRS) protein or its PE domain in HeLa cells, the former was markedly less susceptible to proteasomal degradation. When peptides of varying glycine and alanine content from different PE-PGRS proteins were fused to the N-terminus of SIINFEKL peptide, the alanine-rich fusions elicited lower interleukin-2 responses in SIINFEKL-specific CD8(+) T cells, with corresponding decrease in lysis of cells presenting such peptides. When CD8(+) T cells from Mycobacterium bovis BCG-immunized mice were stimulated with either full-length PE-PGRS protein Rv3812 or its PE domain, the former exhibited a lower level of cytotoxicity against BCG-infected autologous macrophages. These results suggest that mycobacterium PE-PGRS proteins have domains that confer resistance to ubiquitin-proteasome-dependent protein degradation, and the bacteria may have an abundance of such proteins to evade immune detection and killing of mycobacterium-infected cells.