A mouse radiation-induced liver disease model for stereotactic body radiation therapy validated in patients with hepatocellular carcinoma.

PURPOSE: Lower radiation tolerance of the whole liver hinders dose escalations of stereotactic body radiation therapy (SBRT) in hepatocellular carcinoma (HCC) treatment. This study was conducted to define the exact doses that result in radiation-induced liver disease (RILD) as well as to determine dose constraints for the critical organs at risk (OARs) in mice; these parameters are still undefined in HCC SBRT. METHODS: This study consisted of two phases. In the primary phase, mice treated with helical tomotherapy-based SBRT were stratified according to escalating radiation doses to the livers. The pathological differences, signs [such as mouse performance status (MPS)], and serum aspartate aminotransferase (AST)/alanine aminotransferase (ALT)/albumin levels were observed. Radiation-induced disease severities of the OARs were scored using systematic evaluation standards. In the validation phase in humans, 13 patients with HCC who had undergone radiotherapy before hepatectomy were enrolled to validate RILD pathological changes in a mouse study. RESULTS: The evaluation criteria of the mouse liver radiotherapy-related signs were as follows: MPS ≥ 2.0 ± 0.52, AST/ALT ≥ 589.2 ± 118.5/137.4 ± 15.3 U/L, serum albumin ≤ 16.8 ± 2.29 g/L. The preliminary dose constraints of the OARs were also obtained, such as those for the liver (average dose ≤ 26.36 ± 1.71 Gy) and gastrointestinal tract (maximum dose ≤ 22.63 Gy). Mouse RILD models were able to be developed when the livers were irradiated with average doses of ≥31.76 ± 1.94 Gy (single fraction). RILD pathological changes in mice have also been validated in HCC patients. CONCLUSIONS: Mouse RILD models could be developed with SBRT based on the dose constraints for the OARs and evaluation criteria of mouse liver radiotherapy-related signs, and the authors' results favor the study of further approaches to treat HCC with SBRT.

MicroRNA-486-5p, which is downregulated in hepatocellular carcinoma, suppresses tumor growth by targeting PIK3R1.

Deregulated microRNAs and their roles in carcinogenesis and cancer progression have attracted much attention. In previous studies conducted in our laboratory, the Illumina Solexa massively parallel signature sequencing of miRNomes in nontumor and hepatocellular carcinoma (HCC) tissues revealed that miR-486-5p was significantly downregulated in HCC, but its role in HCC development remains unknown. In this study, miR-486-5p levels in HCC tissues and matched control tissues, and in seven HCC cell lines (QGY-7701, QGY-7703, QGY-7404, SMMC-7721, Huh7, HepG2, and PCL/PRF/5) and human normal liver cells (HL-7702), were tested by real-time quantitative RT-PCR. We found that the level of miR-486-5p was significantly decreased in HCC tissue and in all seven HCC cell lines. Overexpression of miR-486-5p markedly suppressed HCC cell proliferation, migration and invasion in vitro, and inhibited HCC growth in vivo. Mechanistically, miR-486-5p was confirmed to directly target PIK3R1 expression, thereby suppressing phosphatidylinositol 3-kinase-AKT pathway activation, by dual luciferase reporter assay and real-time quantitative RT-PCR and western blot analysis. In addition, PIK3R1 knockdown mimicked the effects of miR-486-5p overexpression by inhibiting HCC growth, migration, and invasion. Furthermore, correlation analysis, Kaplan-Meier estimates and Cox proportional hazard models showed an inverse correlation between miR-486-5p and PIK3R1, as well as a shorter time to recurrence after HCC resection, in patients with lower miR-486-5p expression. Hence, we conclude that miR-486-5p, which is frequently downregulated in HCC, inhibits HCC progression by targeting PIK3R1 and phosphatidylinositol 3-kinase-AKT activation.

Suppression of allograft rejection by Tim-1-Fc through cross-linking with a novel Tim-1 binding partner on T cells.

Engagement of T-cell immunoglobulin mucin (Tim)-1 on T cells with its ligand, Tim-4, on antigen presenting cells delivers positive costimulatory signals to T cells. However, the molecular mechanisms for Tim-1-mediated regulation of T-cell activation and differentiation are relatively poorly understood. Here we investigated the role of Tim-1 in T-cell responses and allograft rejection using recombinant human Tim-1 extracellular domain and IgG1-Fc fusion proteins (Tim-1-Fc). In vitro assays confirmed that Tim-1-Fc selectively binds to CD4(+) effector T cells, but not dendritic cells or natural regulatory T cells (nTregs). Tim-1-Fc was able to inhibit the responses of purified CD4(+) T cells that do not express Tim-4 to stimulation by anti-CD3/CD28 mAbs, and this inhibition was associated with reduced AKT and ERK1/2 phosphorylation, but it had no influence on nTregs. Moreover, Tim-1-Fc inhibited the proliferation of CD4(+) T cells stimulated by allogeneic dendritic cells. Treatment of recipient mice with Tim-1-Fc significantly prolonged cardiac allograft survival in a fully MHC-mismatched strain combination, which was associated with impaired Th1 response and preserved Th2 and nTregs function. Importantly, the frequency of Foxp3(+) cells in splenic CD4(+) T cells was increased, thus shifting the balance toward regulators, even though Tim-1-Fc did not induce Foxp3 expression in CD4(+)CD25(-) T cells directly. These results indicate that Tim-1-Fc can inhibit T-cell responses through an unknown Tim-1 binding partner on T cells, and it is a promising immunosuppressive agent for preventing allograft rejection.

[Effects of astilbin on maturation and immunologic function of mouse bone marrow-derived dendritic cells].

OBJECTIVE: To explore the effects of astilbin on the maturation and immunologic function of mouse bone marrow-derived dendritic cells (DCs). METHODS: Mouse bone marrow cells were cultured with recombinant mouse granulocyte-macrophage colony-stimulating factor and interleukin-4 (IL-4) for 5 days to get immature DCs (imDCs), then the imDCs was cultured in the presence of 1 microg/mL lipopolysaccharide (LPS) or LPS (1 microg/mL) plus astilbin (25, 50, 100 microg/mL) for 48 h. Then, the cells were harvested, and the apoptosis, immunophenotypes and antigen phagocytosis capability of imDCs in LPS, and low-, medium- and high-dose astilbin groups were analyzed by flow cytometry. Contents of p40 subunit of interleukin-12 (IL-12p40) in the supernatants were detected with enzyme-linked immunosorbent assay (ELISA). The stimulatory activity of the harvested cells on allogeneic T cells in mixed lymphocyte reactions (MLR) was tested by incorporation of 3H-thymidine, and the contents of IL-2, IL-4, IL-10 and interferon-gamma (INF-gamma) in the supernatants of MLR were examined by ELISA. RESULTS: At the concentrations of 25 to 100 microg/mL, astilbin exhibited no toxicity on co-cultured DCs. Compared with the lipopolysaccharide, low-, medium- and high-dose astilbin could decrease the expression levels of major histocompatibility complex-Ia (MHC-Ia), CD40, CD80 and CD86 molecules in DCs. DCs in the low-, medium- and high-dose astilbin groups exhibited weaker capabilities for antigen phagocytosis and less contents of IL-12p40 in the supernatants than in the LPS group. Furthermore, low-, medium- and high-dose astilbin showed weak activities in stimulating the proliferation of allogeneic T cells as compared with the LPS (P<0.05). Compared with the LPS, low-, medium- and high-dose astilbin could decrease IL-2 and INF-mu secretion from T cells in MLR but had no effect on IL-10 secretion. CONCLUSION: Astilbin can inhibit maturation of mouse bone marrow-derived DCs with dose-dependent effect and exert negative effects on immunologic function of the DCs.

[Protective effects of astilbin on renal ischemia-reperfusion injury in rats].

OBJECTIVE: To investigate the protective effects of astilbin on renal ischemia-reperfusion (IR) injury in rats. METHODS: Twenty-four male SD rats, two months old, were randomly allocated into three groups: sham-operated group (n=8), untreated group (n=8) and astilbin group (n=8). Rats in the untreated group and the astilbin group underwent temporary renal artery occlusion to induce IR injury. The rats in the astilbin group were intraperitoneally injected with 12 mg/mL astilbin at a dose of 30 mg/kg from 3 day before IR injury until to be sacrificed once per day, and rats in the untreated group were injected with equal volume of normal saline at the same time. After 6-hour reperfusion, blood urea nitrogen (BUN) and serum creatinine (SCr) and histological changes of the renal tissues were detected to evaluate renal injury. Expressions of monocyte chemoattractant protein-1 (MCP-1) mRNA and protein in the renal tissues and the serum contents of interleukin-6 (IL-6) and IL-1beta were also measured with semi-quantitative reverse transcription-polymerase chain reaction, Western blotting or enzyme-linked immunosorbent assay. RESULTS: Compared with the untreated group, BUN and SCr levels were significantly decreased in the astilbin group after 6-hour reperfusion (P<0.01), and similar results were also found in histological examination. The expressions of MCP-1 mRNA and protein in renal tissues in the astilbin group were lower than those in the untreated group. The serum contents of IL-6 and IL-1beta were decreased in the astilbin group as compared with the untreated group (P<0.01). CONCLUSION: Astilbin can ameliorate kidney IR injury in rats by inhibiting the production of chemokine MCP-1 and cytokines IL-6 and IL-1beta.

[Effects of kaempferol and quercetin on cytochrome 450 activities in primarily cultured rat hepatocytes].

OBJECTIVE: To observe the effects of kaempferol and quercetin on the activity of cytochrome P450 in rat hepatocytes. METHODS: Primarily cultured rat hepatocytes were exposed to kaempferol or quercetin in concentrations of 0.1, 1, 10 micromol/L for 12 h, 24 h and 48 h. Hepatocytes CYP isoemzymes-erythromycin N-demethylase (ERND) and aminopyrine N-demethylase (ADM) activities were determined by Nash methods. Erythromycin (10 micromol/L) was used as positive control and DMSO(0.1%) as solvent control. RESULTS: Kaempferol and quercetin inhibited ENRD activity in a dose-and time-dependent manner. In dose-response study, the ENRD activities in kaempferol (0.1,1 and 10 micromol/L) treated groups were (0.088+/-0.008), (0.074+/-0.006) and (0.041+/-0.003)micromol/(mg.min(-1)), respectively. ENRD activity in quercetin treated groups at the same concentrations were (0.082+/-0.007), (0.063+/-0.007) and (0.034+/-0.005) micromol/(mg.min(-1)), respectively. In time-courses study, the ENRD activity exposed to 10 micromol/L kaempferol or quercetin for 12 h and 48 h were (0.053+/-0.006) and (0.037+/-0.007) micromol/(mg.min(-1)), or (0.067+/-0.005) and (0.032+/-0.004) micromol/(mg.min(-1)). ADM activity was inhibited only by kaempferol in 10 mol/L at 24 h, but was not significantly altered by quercetin at any concentration tested. CONCLUSION: In the present condition, kaempferol and quercetin act as potential CYP3A4 inhibitors as they can significantly inhibit ENRD in primarily cultured rat hepatocytes.

Alterations in mitochondrial and apoptosis-regulating gene expression in photodynamic therapy-resistant variants of HT29 colon carcinoma cells.

Photodynamic therapy (PDT) is a novel cancer therapy inducing irreversible photodamage to tumor tissue via photosensitizer-mediated oxidative cytotoxicity. The cellular and molecular responses associated with PDT are only partially understood. We have reported previously the generation of several photosensitizer-specific PDT-resistant cell variants of HT29 human colon adenocarcinoma cells by selecting cells from sequential PDT treatment using different photosensitizers. In this report, we describe the use of messenger RNA (mRNA) differential display to identify genes that were differentially expressed in the parental HT29 cells compared with their resistant variants. In comparison with parental HT29 cells, mRNA expression was increased in the PDT-resistant cell variants for BNIP3, estrogen receptor-binding fragment-associated gene 9, Myh-1c, cytoplasmic dynein light chain 1, small membrane protein I and differential dependent protein. In contrast, expression in the PDT-resistant variants was downregulated for NNX3, human HepG2 3' region Mbol complementary DNA, glutamate dehydrogenase, hepatoma-derived growth factor and the mitochondrial genes coding for 16S ribosomal RNA (rRNA) and nicotinamide adenine dinucleotide (NADH) dehydrogenase subunit 4. The reduction for mitochondrial 16S rRNA in the PDT-resistant variants was confirmed by Northern blotting, and the elevated expression of the proapoptotic BNIP3 in the PDT-resistant variants was confirmed by Northern and Western blotting analysis. We also examined the expression of some additional apoptosis-regulating genes using Western blotting. We show an increased expression of Bcl-2 and heat shock protein 27 and a downregulation of Bax in the PDT-resistant variants. In addition, the mutant p53 levels in the parental HT29 cells were reduced substantially in the PDT-resistant variants. We suggest that the altered expression in several mitochondrial and apoptosis-regulating genes contributes to PDT resistance.