The Prognostic Value of Alpha-Fetoprotein Ratio in Patients With Resectable Alpha-Fetoprotein-Negative Hepatocellular Carcinoma.

PURPOSE: This study aimed to investigate the prognostic value of alpha-fetoprotein (AFP) ratio in patients with AFP-negative hepatocellular carcinoma (HCC). PATIENTS AND METHODS: We retrospectively analyzed 600 AFP-negative HCC patients who underwent hepatectomy. The AFP ratio was calculated as the ratio of AFP level 1 week before surgery to the level 20-40 days after hepatectomy. Immunohistochemistry assay was used to assess protein expression in HCC tissue. The primary outcome measures were overall survival (OS) and disease-free survival (DFS). RESULTS: The study found that a cutoff value of 1.6 ng/ml for AFP ratio, determined using X-tile software, was optimal for predicting prognosis. Patients with a high AFP ratio had a worse prognosis compare to those with a low AFP ratio (DFS, P = .026; OS, P = .034). Patients with a high AFP ratio had a worse prognosis compared to those with a low AFP ratio. Multivariate analysis revealed that AFP ratio >1.6, negative HepPar-1 expression, and vascular invasion were independent predictors of both DFS and OS. Vascular invasion had a higher area under the curve (AUC) than AFP ratio and HepPar-1 expression in predicting recurrence and death. The combination of AFP ratio, HepPar-1 expression, and vascular invasion provided better predictive accuracy for DFS and OS. CONCLUSION: The AFP ratio is a potential prognostic marker for AFP-negative HCC patients after hepatectomy. Combining the analysis of AFP ratio with HepPar-1 expression and vascular invasion can enhance the accuracy of predicting prognosis in these patients.

The novel methyltransferase SETD4 regulates TLR agonist-induced expression of cytokines through methylation of lysine 4 at histone 3 in macrophages.

The production of inflammatory cytokines is closely related to pathogen-associated molecular pattern (PAMP)-triggered activation of the Toll-like receptor (TLR), intracellular signal transduction pathways such as MAPK and NF-κB, and histone modifications. Histone methylation, a type of histone modifications, is mainly accomplished by a class of SET family proteins containing highly conserved SET domains. In the present study, we found that SET domain-containing protein 4 (SETD4) regulated inflammatory cytokines in response to TLR agonists. LPS stimulation led to the enhanced SETD4 expression, while the increased IL-6 and TNF-α release from LPS-stimulated RAW264.7 cells was attenuated by depletion of SETD4 using RNA interference. The results were further confirmed in BMDMs and pMφ isolated from SETD4-deficient mice where SETD4-/- macrophages treated with LPS, BLP or Poly(I:C) showed down-regulated IL-6 and TNF-α mRNA and protein levels when compared with SETD4+/+ macrophages. Moreover, the mRNA levels of all NF-κB-dependent genes including IL-1ß, IL-10, NFKBA, DUSP1, CCL2, CCL5, and CXCL10 in SETD4-/- macrophages were substantially reduced. To further clarify the regulatory mechanism(s) by which SETD4 modulates inflammatory cytokines, we examined the effect of SETD4 on the activation of MAPK and NF-κB signalling pathways, and found that knockout of SETD4 had no effect on phosphorylation of p38, ERK, JNK, p65, and IκBα. Notably, SETD4 translocated quickly from the cytosol to the nucleus upon LPS stimulation, suggesting that SETD4 may exert its regulatory function downstream of the MAPK and NF-κB pathways. To characterize this, we performed an in vitro HMTase assay to measure histone methyltransferase (HMTase) activity of SETD4. H3K4me1 and H3K4me2 levels were enhanced dramatically with the supplementation of SETD4, whereas both H3K4me1 and H3K4me2 were strongly attenuated in SETD4-/- BMDMs. Moreover, the LPS-stimulated recruitment of H3K4me1 and H3K4me2 at both TNF-α and IL-6 promoters was severely impaired in SETD4-/- BMDMs. Collectively, these results demonstrate that SETD4 positively regulates IL-6 and TNF-α expression in TLR agonist-stimulated macrophages by directly activating H3K4 methylation.

H3K4 Methylation Regulates LPS-Induced Proinflammatory Cytokine Expression and Release in Macrophages.

Histone methylation is an important epigenetic mechanism that plays an essential role in regulating gene expression in mammalian cells. To understand its influence on inflammation, methylation of H3K4, H3K9, H3K36, H3K79, and H4K20, the most common histones methylated in the inflammatory response was analyzed in murine RAW264.7 cells and bone marrow-derived macrophages (BMDMs) upon lipopolysaccharide (LPS) stimulation. LPS stimulation resulted in enhanced methylation at H3K4 and H3K9 in both RAW264.7 and BMDMs. To further confirm whether LPS-stimulated H3K4me2 and H3K9me2 were responsible for subsequent proinflammatory cytokine expression, the recruitment of H3K4me2 and H3K9me2 at the promoters of interleukin (IL)-6 and tumor necrosis factor-α (TNF-α) was assessed. H3K4me2, but not H3K9me2, was enriched at the promoters of both IL-6 and TNF-α. Furthermore, LPS-stimulated gene expression and release of IL-6 and TNF-α were markedly suppressed in macrophages by MTA, a specific inhibitor of H3K4 methylation. These results demonstrate that histone methylation, in particular H3K4me2, plays a critical role in the regulation of LPS-induced expression and release of IL-6 and TNF-α.

PRAK interacts with DJ-1 and prevents oxidative stress-induced cell death.

As a core member of p38 MAPK signal transduction pathway, p38 regulated/activated kinase (PRAK) is activated by cellular stresses. However, the function of PRAK and its downstream interacting partner remain undefined. Using a yeast two-hybrid system, we identified DJ-1 as a potential PRAK interacting protein. We further verified that DJ-1 bound to PRAK in vitro and in vivo and colocalized with PRAK in the nuclei of NIH3T3 cells. Furthermore, following H2O2 stimulation the majority of endogenous DJ-1 in PRAK(+/+) cells still remained in the nucleus, whereas most DJ-1 in PRAK(-/-) cells translocated from the nucleus into the cytoplasm, indicating that PRAK is essential for DJ-1 to localize in the nucleus. In addition, PRAK-associated phosphorylation of DJ-1 was observed in vitro and in vivo of H2O2-challenged PRAK(+/+) cells. Cytoplasmic translocation of DJ-1 in H2O2-treated PRAK(-/-) cells lost its ability to sequester Daxx, a death protein, in the nucleus, and as a result, Daxx gained access to the cytoplasm and triggered cell death. These data highlight that DJ-1 is the downstream interacting target for PRAK, and in response to oxidative stress PRAK may exert a cytoprotective effect by facilitating DJ-1 to sequester Daxx in the nucleus, thus preventing cell death.