Mycobacterium tuberculosis is a hard-to-eradicate intracellular pathogen that infects one-third of the global population. It can live within macrophages owning to its ability to arrest phagolysosome biogenesis. Autophagy has recently been identified as an effective way to control the intracellular mycobacteria by enhancing phagosome maturation. In the present study, we demonstrate a novel role of miR-155 in regulating the autophagy-mediated anti-mycobacterial response. Both in vivo and in vitro studies showed that miR-155 expression was significantly enhanced after mycobacterial infection. Forced expression of miR-155 accelerated the autophagic response in macrophages, thus promoting the maturation of mycobacterial phagosomes and decreasing the survival rate of intracellular mycobacteria, while transfection with miR-155 inhibitor increased mycobacterial survival. However, macrophage-mediated mycobacterial phagocytosis was not affected after miR-155 overexpression or inhibition. Furthermore, blocking autophagy with specific inhibitor 3-methyladenine or silencing of autophagy related gene 7 (Atg7) reduced the ability of miR-155 to promote autophagy and mycobacterial elimination. More importantly, our study demonstrated that miR-155 bound to the 3′-untranslated region of Ras homologue enriched in brain (Rheb), a negative regulator of autophagy, accelerated the process of autophagy and sequential killing of intracellular mycobacteria by suppressing Rheb expression. Our results reveal a novel role of miR-155 in regulating autophagy-mediated mycobacterial elimination by targeting Rheb, and provide potential targets for clinical treatment.
microRNA-155 (miR-155) plays an essential role in regulating the host immune response by post-transcriptionally repressing the expression of target genes. However, little is known regarding its activity in modulating autophagy, an important host defense mechanism against intracellular bacterial infection. Mycobacterium tuberculosis is a hard-to-eradicate intracellular pathogen that infects approximately one-third of the global population, and causes 1.5 million deaths annually. The present study explores a novel role of miR-155 in the host response against mycobacterial infection. Our data demonstrates that mycobacterial infection triggers the expression of miR-155, and the induction of miR-155 in turn activates autophagy by targeting Rheb, a negative regulator of autophagy. miR-155-promoted autophagy accelerates the maturation of the mycobacterial phagosome, thus decreasing the survival of intracellular mycobacteria in macrophages. These findings contribute to a better understanding of the host defense mechanisms against mycobacterial infection, providing useful information for development of potential therapeutic interventions against tuberculosis.
Cancer remains a leading cause of death worldwide and total number of cases globally is increasing. Novel treatment strategies are therefore desperately required for radical treatment of cancers and long survival of patients. A new technology using high pulsed electric field has emerged from military application into biology and medicine by applying nsPEF as a means to inhibit cancer. However, molecular mechanisms of nsPEF on tumors or cancers are still unclear. In this paper, we found that nsPEF had extensive biological effects in cancers, and clarified its possible molecular mechanisms in vitro and in vivo. It could not only induce cell apoptosis via dependent-mitochondria intrinsic apoptosis pathway that was triggered by imbalance of anti- or pro-apoptosis Bcl-2 family proteins, but also inhibit cell proliferation through repressing NF-κB signaling pathway to reduce expressions of cyclin proteins. Moreover, nsPEF could also inactivate metastasis and invasion in cancer cells by suppressing Wnt/β-Catenin signaling pathway to down-regulating expressions of VEGF and MMPs family proteins. More importantly, nsPEF could function safely and effectively as an anti-cancer therapy through inducing tumor cell apoptosis, destroying tumor microenvironment, and depressing angiogenesis in tumor tissue in vivo. These findings may provide a creative and effective therapeutic strategy for cancers.
Tibet, average altitude more than 4,000 meters, is warming faster than anywhere else in China. The increase in temperatures may aggravate existing health problems and lead to the emergence of new risks. However, there are no actions being taken at present to protect population health due to limited understanding about the range and magnitude of health effects of climate change.
The study was a cross-sectional survey of 619 respondents from urban Lhasa, Tibet in August 2012 with the aim to investigate public perceptions of risk, heat experiences, and coping resources.
Respondents are aware of the warming that has occurred in Lhasa in recent years. Over 78% reported that rising temperature is either a “very” or “somewhat” serious threat to their own health, and nearly 40% reported they had experienced heat-related symptoms. Sex, age, education and income influenced perceived risks, health status, and heat experience. The vast majority of respondents reported that they had altered their behaviour on hot summer days. Bakuo, a sub-district at the city center, is considered especially vulnerable to heat because of sparse vegetation, high population density, poor dwelling conditions and a high proportion of low-income population. However, neighborhood social ties were stronger in Bakuo than other study locations.
The study suggests that actions are needed now to minimize downside effects of rapid warming in Tibet, because of increasing human exposure to high temperatures and uneven distribution of the resources needed to cope.
Climate change; Global warming; Perceptions; Human health; Tibet; Vulnerability
To evaluate the effect of Chinese herbal medicine (CHM) on albuminuria levels in patients with diabetic nephropathy (DN), we performed comprehensive searches on Medline database, Cochrane Library, CNKI database, CBM database, Wanfang database, and VIP database up to December 2012. A total of 29 trials including 2440 participants with DN met the selection criteria. CHM was tested to be more effective in reducing urinary albumin excretion rate (UAER) (MD −82.95 μg/min, [−138.64, −27.26]) and proteinuria (MD −565.99 mg/24 h, [−892.41, −239.57]) compared with placebo. CHM had a greater beneficial effect on reduction of UAER (MD −13.41 μg/min, [−20.63, −6.19]) and proteinuria (MD −87.48 mg/24 h, [−142.90, −32.06]) compared with angiotensin converting enzyme inhibitors (ACEI) or angiotensin receptor blockers (ARB). Combination therapy with CHM and ACEI/ARB showed significant improvement in UAER (MD −28.18 μg/min, [−44.4, −11.97]), urinary albumin-creatinine ratio (MD −347.00, [−410.61, −283.39]), protein-creatinine ratio (MD −2.49, [−4.02, −0.96]), and proteinuria (MD −26.60 mg/24 h, [−26.73, −26.47]) compared with ACEI/ARB alone. No serious adverse events were reported. CHM seems to be an effective and safe therapy option to treat proteinuric patients with DN, suggesting that further study of CHM in the treatment of DN is warranted in rigorously designed, multicentre, large-scale trials with higher quality worldwide.
Increasing evidence indicates that deregulation of microRNAs (miRNAs) is involved in tumorigenesis. Downregulation of microRNA-503 has been observed in various types of diseases, including cancer. However, the biological function of miR-503 in hepatocellular carcinoma (HCC) is still largely unknown. In this study we aimed to elucidate the prognostic implications of miR-503 in HCC and its pathophysiologic role.
Quantitative reverse transcriptase polymerase chain reaction was used to evaluate miR-503 expression in HCC tissues and cell lines. Western blotting was performed to evaluate the expression of the miR-503 target genes. In vivo and in vitro assays were performed to evaluate the function of miR-503 in HCC. Luciferase reporter assay was employed to validate the miR-503 target genes.
miR-503 was frequently downregulated in HCC cell lines and tissues. Low expression levels of miR-503 were associated with enhanced malignant potential such as portal vein tumor thrombi, histologic grade, TNM stage, AFP level and poor prognosis. Multivariate analysis indicated that miR-503 downregulation was significantly associated with worse overall survival of HCC patients. Functional studies showed miR-503 suppressed the proliferation of HCC cells by induction of G1 phase arrest through Rb-E2F signaling pathways, and thus may function as a tumor suppressor. Further investigation characterized two cell cycle-related molecules, cyclin D3 and E2F3, as the direct miR-503 targets.
Our data highlight an important role for miR-503 in cell cycle regulation and in the molecular etiology of HCC, and implicate the potential application of miR-503 in prognosis prediction and miRNA-based HCC therapy.
Hepatocellular carcinoma; microRNA-503; Cyclin D3; E2F3; Overall survival; G1/S transition
The I405V polymorphism of the cholesteryl ester transfer protein gene (CETP) has been suggested to be a protective factor conferring longevity in Ashkenazi Jews, although findings in other races are not supportive. This paper describes a case-control study and a meta-analysis conducted to derive a more precise estimation of the association between CETP 405V and longevity.
We enrolled 1,021 ethnic Han Chinese participants (506 in the longevity group and 515 controls), then performed a meta-analysis that integrated the current study and previously published ones. Pooled odds ratios (OR) were calculated for allele contrasts, dominant and recessive inheritance models to assess the association between CETP 405V and longevity according to the ethnic stratification.
Our case-control data indicated that CETP 405V is a longevity risk allele in all genetic models (Padditive=0.008; Pdominant=0.008, ORdominant=0.673; Precessive=0.017, ORrecessive=0.654) after adjustment for the apolipoprotein E (APOE) ε4 allele, body mass index and high-density lipoprotein cholesterol. A synergy was detected between 405V and APOE ε4 (P=0.001, OR=0.530). Eight studies were eligible for meta-analysis, which confirmed 405V is the risky allele against longevity in all genetic models: allele contrasts (OR=0.81, 95%CI=0.74-0.88), dominant model (OR=0.72, 95%CI=0.64-0.82) and recessive model (OR=0.80, 95%CI=0.67-0.96). After ethnic stratification, 405V remained a risk allele in East Asians but no significant association was found in Europeans or white Americans.
Our case-control study suggests CETP 405V as a risk allele against longevity in Chinese. The meta-analysis suggests the involvement of CETP 405V is protective in Ashkenazi Jews but is a risk allele against longevity in the East Asian (Chinese) population.
In 2009, residents of Lhasa city, Tibet Autonomous Region (TAR), China reported large numbers of mosquitoes and bites from these insects. It is unclear whether this was a new phenomenon, which species were involved, and whether these mosquitoes had established themselves in the local circumstances.
The present study was undertaken in six urban sites of Chengguan district Lhasa city, Tibet. Adult mosquitoes were collected by bed net trap, labor hour method and light trap in August 2009 and August 2012. The trapped adult mosquitoes were initially counted and identified according to morphological criteria, and a proportion of mosquitoes were examined more closely using a multiplex PCR assay.
907 mosquitoes of the Culex pipiens complex were collected in this study. Among them, 595 were females and 312 were males. There was no significant difference in mosquito density monitored by bed net trap and labor hour method in 2009 and 2012. Of 105 mosquitoes identified by multiplex PCR, 36 were pure mosquitoes (34.29%) while 69 were hybrids (65.71%). The same subspecies of Culex pipiens complex were observed by bed net trap, labor hour method and light trap in 2009 and 2012.
The local Culex pipiens complex comprises the subspecies Cx. pipiens pipiens, Cx. pipiens pallens, Cx. pipiens quinquefasciatus and its hybrids. Mosquitoes in the Cx. pipiens complex, known to be, potentially, vectors of periodic filariasis and encephalitis, are now present from one season to the next, and appear to be established in Lhasa City, TAR.
Mosquitoes; Culex pipiens complex; Multiplex PCR; Established; Lhasa
Nitrite-preserved meats (e.g., hot dogs) may help cause colon cancer because they contain N-nitroso compounds. We tested whether purified hot-dog-derived total apparent N-nitroso compounds (ANC) could induce colonic aberrant crypts, which are putative precursors of colon cancer. We purified ANC precursors in hot dogs and nitrosated them to produce ANC. In preliminary tests, CF1 mice received 1 or 3 i.p. injections of 5mg azoxymethane (AOM)/kg. In Experiments 1 and 2, female A/J mice received ANC in diet. In Experiment 1, ANC dose initially dropped sharply because the ANC precursors had mostly decomposed but, later in Experiment 1 and throughout Experiment 2, ANC remained at 85 nmol/g diet. Mice were killed after 8 (AOM tests) or 17–34 (ANC tests) wk. Median numbers of aberrant crypts in the distal 2 cm of the colon for 1 and 3 AOM injections, CF1 controls, ANC (Experiment 1), ANC (Experiment 2),and untreated A/J mice were 31, 74, 12, 20, 12, and 5–6, with P < 0.01 for both ANC tests. Experiment 2 showed somewhat increased numbers of colonic mucin-depleted foci in the ANC-treated group. We conclude that hot-dog-derived ANC induced significant numbers of aberrant crypts in the mouse colon.
Aberrant Crypt Foci; chemically induced; Animals; Azoxymethane; administration & dosage; toxicity; Carcinogens; toxicity; Colonic Neoplasms; chemically induced; Feces; chemistry; Female; Food Handling; Meat Products; analysis; toxicity; Mice; Nitrosation; Nitroso Compounds; analysis; toxicity; Sodium Nitrite; administration & dosage; metabolism
Extracellular vesicles (EVs) carry signals within or at their limiting membranes, providing a mechanism by which cells can exchange more complex information than what was previously thought. In addition to mRNAs and microRNAs, there are DNA fragments in EVs. Solexa sequencing indicated the presence of at least 16434 genomic DNA (gDNA) fragments in the EVs from human plasma. Immunofluorescence study showed direct evidence that acridine orange-stained EV DNAs could be transferred into the cells and localize to and inside the nuclear membrane. However, whether the transferred EV DNAs are functional or not is not clear. We found that EV gDNAs could be homologously or heterologously transferred from donor cells to recipient cells, and increase gDNA-coding mRNA, protein expression, and function (e.g. AT1 receptor). An endogenous promoter of the AT1 receptor, NF-κB, could be recruited to the transferred DNAs in the nucleus, and increase the transcription of AT1 receptor in the recipient cells. Moreover, the transferred EV gDNAs have pathophysiological significance. BCR/ABL hybrid gene, involved in the pathogenesis of chronic myeloid leukemia, could be transferred from K562 EVs to HEK293 cells or neutrophils. Our present study shows that the gDNAs transferred from EVs to cells have physiological significance, not only to increase the gDNA-coding mRNA and protein levels, but also to influence function in recipient cells.
extracellular vesicles; genomic DNA; AT1 receptor; BCR/ABL hybrid gene
Aliskiren is a novel renin-angiotensin aldosterone system (RAAS) inhibitor, the combination therapy of aliskiren and amlodipine for blood pressure control have been reported recently. The primary objective of this analysis is to review recently reported randomized controlled trials (RCTs) to compare antihypertensive effects and adverse events between mono (amlodipine or aliskiren alone) and combination therapy of both medicines.
Databases for the search included Pubmed, Embase and the Cochrane Central Register of Controlled Trials. Revman v5.0 statistical program was used to analyze the data. Weighted mean differences (WMD) with a 95% confidence interval (CI) were used for the calculation of continuous data, and relative risk (RR) with a 95% CI was used for dichotomous data.
We analyzed the data from 7 RCTs for a total of 6074 participants in this meta-analysis. We found that the aliskiren/amlodipine combination therapy had a stronger effect in lowering blood pressure as compared with the monotherapy using aliskiren (SBP: WMD = −10.42, 95% CI −13.03∼−7.82, P<0.00001; DBP: WMD = −6.60, 95% CI −7.22∼−5.97, P<0.00001) or amlodipine (SBP: WMD = −4.85, 95% CI −6.88∼−2.81, P<0.00001; DBP: WMD = −2.91, 95% CI −3.85∼−1.97, P<0.00001). No differences were found in terms of adverse events between combination therapy and monotherapy, except for the rates of peripheral edema and hypokalaemia which were significantly lower in the combination therapy than in the amlodipine monotherapy (RR = 0.78, 0.66∼0.92, P = 0.004; RR = 0.51, 0.27∼0.97, P = 0.04). Similar antihypertensive effects were found in both obese (body mass index > = 30 kg/m2) hypertensive and non-obese (body mass index <30 kg/m2) hypertensive patients. Moreover, there was no difference with the blood pressure lowering or adverse effects with regards to the combination therapy in both subgroups.
We found that aliskiren/amlodipine combination therapy provided a more effective blood pressure reduction than monotherapy with either drug without increase in the occurrence of adverse events.
Vascular smooth muscle cell (VSMC) proliferation is central to the development of vascular diseases, including hypertension, which is regulated by numerous hormones and humoral factors. Our previous study showed that the stimulatory effect of norepinephrine on VSMC proliferation is inhibited by D1-like receptors and the D3 dopamine receptor, a member of the D2-like receptor family. Insulin is a proliferative hormone but it is not known if there is any interaction between insulin and D1-like receptors. We hypothesized that Dl-like receptors may have an inhibitory effect on the insulin-induced VSMC proliferation; aberrant insulin and Dl-like receptor functions could be involved in the pathogenesis of essential hypertension.
VSMC proliferation was determined by [3H]-thymidine incorporation; insulin receptor mRNA and protein expressions were determined by RT-PCR, immunoblotting, and immunohistochemistry.
Insulin increased VSMC proliferation in immortalized aortic A10 cells, determined by [3H]-thymidine incorporation. Although the D1-like receptor, by itself, had no effect on VSMC proliferation, stimulation with fenoldopam, a D1-like receptor agonist, inhibited the stimulatory effect of insulin. The inhibitory effect of fenoldopam on insulin-mediated VSMC proliferation was receptor specific, because its effect could be blocked by SCH23390, a D1-like receptor antagonist. Fenoldopam also inhibited insulin receptor mRNA and protein expression, which was time dependent and concentration dependent. A PKC or MAP kinase inhibitor blocked the inhibitory effect of fenoldopam on insulin receptor expression, indicating that PKC and MAP kinase were involved in the signaling pathway.
The inhibitory effect of D1-like receptors on insulin-mediated VSMC proliferation may play an important role in the regulation of blood pressure.
dopamine receptor; insulin; proliferation; vascular smooth muscle cells
Vascular smooth muscle cell (VSMC) proliferation is regulated by numerous hormones and humoral factors. Our previous study found that stimulation of D1-like dopamine receptors inhibited insulin receptor expression and function in VSMCs. We hypothesize that there is also an interaction between D3 dopamine and insulin receptors, i.e., stimulation of the D3 receptor inhibits insulin receptor expression and function.
Receptor expression was determined by immunoblotting, immunohistochemisty, and reverse transcriptase-PCR; VSMC proliferation was determined by 3-(4,5-dimethylthiazol-2-yl)-diphenyl-tetrazolium bromide (MTT) assay and cell number.
Insulin receptor protein is increased in the aorta of D3 receptor deficient mice. Stimulation of the D3 receptor inhibited insulin receptor mRNA and protein expression and insulin-mediated VSMC proliferation, and increased protein kinase A (PKA) activity, insulin receptor phosphorylation, and degradation in immortalized aortic VSMCs (A10 cells). These effects were blocked by a PKA inhibitor, indicating that the D3 receptor-mediated decrease in insulin receptor expression was related to a decrease in transcription/post-transcription and increased degradation, involving PKA signaling.
D3 receptor stimulation may be a target to reduce the adverse effect of insulin in hypertension by inhibition of insulin receptor expression and function in arterial VSMCs.
blood pressure; dopamine receptor; hypertension; insulin receptor; proliferation; vascular smooth muscle cells
Essential hypertension is a major risk factor for stroke, myocardial infarction, and heart and kidney failure. Dopamine plays an important role in the pathogenesis of hypertension by regulating epithelial sodium transport and by interacting with vasoactive hormones and humoral factors. However, the mechanisms leading to impaired dopamine receptor function in hypertension states are not clear. Compelling experimental evidence indicates a role of reactive oxygen species (ROS) in hypertension, and there are increasing pieces of evidence showing that in conditions associated with oxidative stress, which is present in hypertensive states, dopamine receptor effects, such as natriuresis, diuresis, and vasodilation, are impaired. The goal of this review is to present experimental evidence that has led to the conclusion that decreased dopamine receptor function increases ROS activity and vice versa. Decreased dopamine receptor function and increased ROS production, working in concert or independent of each other, contribute to the pathogenesis of essential hypertension.
reactive oxygen species; essential hypertension; dopamine receptor
RING box protein-1 (RBX1) is an essential component of Skp1-cullin-F-box protein (SCF) E3 ubiquitin ligase and participates in diverse cellular processes by targeting various substrates for degradation. However, the physiological function of RBX1 in mouse oocyte maturation remains unknown. Here, we examined the expression, localization and function of RBX1 during mouse oocyte meiotic maturation. Immunofluorescence analysis showed that RBX1 displayed dynamic distribution during the maturation process: it localized around and migrated along with the spindle and condensed chromosomes. Rbx1 knockdown with the appropriate siRNAs led to a decreased rate of first polar body extrusion and most oocytes were arrested at metaphase I. Moreover, downregulation of Rbx1 caused accumulation of Emi1, an inhibitor of the anaphase-promoting complex/cyclosome (APC/C), which is required for mouse meiotic maturation. In addition, we found apparently increased expression of the homologue disjunction-associated protein securin and cyclin B1, which are substrates of APC/C E3 ligase and need to be degraded for meiotic progression. These results indicate the essential role of the SCFβTrCP-EMI1-APC/C axis in mouse oocyte meiotic maturation. In conclusion, we provide evidence for the indispensable role of RBX1 in mouse oocyte meiotic maturation.
The renin–angiotensin (Ang) system controls blood pressure, in part, by regulating renal tubular sodium transport. In the kidney, activation of the angiotensin II type 1 (AT1) receptor increases renal sodium reabsorption, whereas the angiotensin II type 2 (AT2) receptor produces the opposite effect. We hypothesized that the AT2 receptor regulates AT1 receptor expression and function in the kidney.
Methods and results
In immortalized renal proximal tubule (RPT) cells from Wistar–Kyoto rats, CGP42112, an AT2 receptor agonist, decreased AT1 receptor mRNA and protein expression (P < 0.05), as assessed by reverse transcriptase-polymerase chain reaction and immunoblotting. The inhibitory effect of the AT2 receptor on AT1 receptor expression was blocked by the AT2 receptor antagonist, PD123319 (10−6 mol/l), the nitric oxide synthase inhibitor Nw-nitro-l-arginine methyl ester (10−4 mol/l), or the nitric oxide-dependent soluble guanylate cyclase inhibitor 1H-[1,2,4] oxadiazolo-[4,3-a] quinoxalin-1-one (10−5 mol/l), indicating that both nitric oxide and cyclic guanosine monophosphate (cGMP) were involved in the signaling pathway. Furthermore, CGP42112 decreased Sp1 serine phosphorylation and reduced the binding of Sp1 to AT1 receptor DNA. Stimulation with Ang II (10−11 mol/l per 30 min) enhanced Na+-K+-ATPase activity in RPT cells, which was prevented by pretreatment with CGP42112 (10−7 mol/l per 24 h) (P < 0.05). The above-mentioned results were confirmed in RPT cells from AT2 receptor knockout mice; AT1 receptor expression and Ang II-stimulated Na+-K+-ATPase activity were greater in these cells than in RPT cells from wild-type mice (P < 0.05). AT1/AT2 receptors co-localized and co-immunoprecipitated in RPT cells; short-term CGP42112 (10−7 mol/l per 30 min) treatment increased AT1/AT2 receptor co-immunoprecipitation (P < 0.05).
These results indicate that the renal AT2 receptor, via nitric oxide/cGMP/Sp1 pathway, regulates AT1 receptor expression and function, which may be important in the regulation of sodium excretion and blood pressure.
AT1 receptor; AT2 receptor; hypertension; renal proximal tubule cells
Ion transport in the renal proximal tubule (RPT) is regulated by numerous hormones and humoral factors, including insulin and dopamine. Previous studies show an interaction between insulin and the D1 receptor. Because both D1 and D5 receptors belong to the D1-like receptor subfamily, it is possible that an interaction between insulin and the D5 dopamine receptor exists in RPT cells from normotensive Wistar-Kyoto (WKY) rats and spontaneously hypertensive rats (SHRs).
D5 receptor expression in immortalized RPT cells from WKY and SHRs was quantified by immunoblotting and D5 receptor function by measuring Na+–K+ ATPase activity.
Insulin increased the expression of the D5 receptor. Stimulation with insulin (10−7 mol/l) for 24 h increased D5 receptor expression in RPT cells from WKY rats. This effect of insulin on D5 receptor expression was aberrant in RPT cells from SHRs. The stimulatory effect of insulin on D5 receptor expression in RPT cells from WKY rats was inhibited by a protein kinase C (PKC) inhibitor (PKC inhibitor peptide 19–31, 10−6 mol/l) or a phosphatidylinositol 3 (PI3) kinase inhibitor (wortmannin, 10−6 mol/l), indicating that both PKC and PI3 kinase were involved in the signaling pathway. Stimulation of the D5 receptor heterologously expressed in HEK293 cells with fenoldopam (10−7 mol/l/15 min) inhibited Na+–K+ ATPase activity, whereas pretreatment with insulin (10−7 mol/l/24 h) increased the D5 receptor-mediated inhibition.
Insulin and D5 receptors interact to regulate renal sodium transport; an aberrant interaction between insulin and D5 receptor may participate in the pathogenesis of hypertension.
The epithelial-to-mesenchymal transition (EMT) and mesenchymal-to-epithelial transition (MET) play pivotal roles in metastasis of epithelial cancers. The distinction between them has shed new light on the molecular mechanisms of tumor metastasis. Recently, tumor microenvironment (TM) has been identified as one of the most potent inducers of EMT and MET. TM is characterized by its complexity and flexibility. The purpose of this study was to ascertain the exact effect of each distinct TM component on the evolution hepatocellular carcinoma (HCC) metastasis.
Two different cell culture models were used. The HCC cell line Bel-7402 was co-cultured with the normal liver cell line HL-7702 or with the retinal vascular endothelial cell line RF/6A in double-layer six-well plates, imitating the direct interaction between tumor-host cells and tumor cells. Bel-7402 was also cultured in the conditioned medium (CM) of the human lung fibroblast cell line MRC-5, HL-7702 or RF/6A, imitating an indirect interaction. Integrin β1, β3, β4, β7, laminin β3, E-cadherin and Snail levels were measured by quantitative RT-PCR in tumor sepecimens from 42 resected HCC.
We found that Bel-7402 cells co-cultured with HL-7702 or RF/6A cells were induced to undergo MET. The expression of E-cadherin, α-catenin and β-catenin was up-regulated, accompanied with a strengthened E-cadherin/catenin complex on the membrane of co-cultured Bel-7402 cells. Consequently, the invasion and migration ability of cells was declined. Conversely, Bel-7402 cells cultured in conditioned medium from MRC-5 cells underwent an EMT-like transformation as the cells became elongated with increased invasion and migration ability. Furthermore, we demonstrated that HL-7702 cells could generally inhibit the tumorigenicity and viability of Bel-7402 cells. We also found that integrin β1 expression was negatively associated with capsular formation, and that integrin β4 expression was negatively associated with CK19 expression.
Our findings highlight the strong influences exerted by TM on tumor progression through EMT and MET by impacting the expression of adhesion molecules, including the E-cadherin/catenin complex, laminins and integrins.
Tumor microenvironment; EMT; MET; Co-culture; Conditioned medium culture
The secretion function of intestinal graft is one of the most important factors for successful intestinal transplantation. Cystic fibrosis transmembrane conductance regulator (CFTR) mediates HCO3- and Cl- secretions in intestinal epithelial cells. In this study, we made investigation on the expression and function of CFTR in an experimental model of murine small intestinal transplantation. Heterotopic intestinal transplantations were performed in syngeneic mice. The mRNA and protein expressions of CFTR were analyzed by real time PCR and western blot. Murine intestinal mucosal HCO3- and Cl- secretions were examined in vitro in Ussing chambers by the pH stat and short circuit current (Isc) techniques. The results showed that forskolin, an activator of CFTR, stimulated jejunal mucosal epithelial HCO3- and Cl- secretions in mice, but forskolin-stimulated HCO3- and Cl- secretions in donor and recipient jejunal mucosae of mice after heterotopic jejunal transplantation were markedly decreased, compared with controls (P<0.001). The mRNA and protein expression levels of CFTR in donor and recipient jejunal mucosae of mice were also markedly lower than those in controls (P<0.001), and the mRNA and protein expression levels of tumor necrosis factor α (TNFα) were markedly increased in donor jejunal mucosae of mice (P<0.001), compared with controls. Further experiments showed that TNFα down-regulated the expression of CFTR mRNA in murine jejunal mucosa. In conclusion, after intestinal transplantation, the function of CFTR was impaired, and its mRNA and protein expressions were down-regulated, which may be induced by TNFα.
Hepatitis B virus-associated hepatocellular carcinoma (HBV-HCC) and hepatitis C virus (HCV)-HCC are the main indications for liver transplantation. We compared differences in survival outcomes between these two conditions.
Methods and Findings
The China Liver Transplant Registry (CLTR) contains data collated from all transplants performed in 86 liver transplantation centers across China. We analyzed CLTR data from January 1999 to December 2010. In all, 7,658 patients (7,162 with HBV-HCC and 496 with HCV-HCC) were included in this study. Clinical characteristics were compared between the HBV-HCC and HCV-HCC groups; Kaplan–Meier analysis was used to calculate the overall, tumor-free and hepatitis-free survival rates. The 1-year, 3-year and 5-year overall survival was significantly higher in HBV-HCC recipients than in HCV-HCC recipients (76.65%, 56.61% and 49.10% vs. 64.59%, 42.78% and 39.20%, respectively; P<0.001). The corresponding tumor-free survival rates (63.55%, 47.37%, 40.99% vs. 56.84%, 38.04%, 35.66%, respectively) and hepatitis-free survival rates (75.49%, 54.84%, 47.34% vs. 63.87%, 42.15%, 39.33%, respectively) were both superior in HBV-HCC recipients (both P<0.001). Multivariate analyses identified hepatitis, preoperative alpha-fetoprotein (AFP) level, size of largest tumor, number of tumor nodules, TNM stage, vascular invasion and preoperative model for end-stage liver disease (MELD) score as independent predictors of overall, tumor-free and hepatitis-free survival.
Survival outcomes after liver transplantation were significantly better in HBV-HCC patients than in HCV-HCC patients. This finding may be used to guide donor liver allocation in transplantation programs.
C5aR is a G protein-coupled receptor for the anaphylatoxin C5a and mediates many pro-inflammatory reactions. C5aR signaling has also been shown to regulate T cell immunity, but its sites and mechanism of action in this process remains uncertain. Here, we created a green fluorescence protein (GFP) knock-in mouse and used GFP as a surrogate marker to examine C5aR expression. GFP was knocked into the 3′-untranslated region (3′-UTR) of C5aR by gene targeting. We show that GFP is expressed highly on Gr-1+CD11b+ cells in the blood, spleen and bone marrow (BM), and moderately on CD11b+F4/80+ circulating leukocytes and elicited peritoneal macrophages. No GFP is detected on resting or activated T lymphocytes, nor on splenic myeloid or plasmacytoid dendritic cells. In contrast, 5–20% cultured BM-derived dendritic cells expressed GFP. Interestingly, GFP knock-in prevented cell surface but not intracellular C5aR expression. We conclude that C5aR is unlikely to play an intrinsic role on murine T cells and primary DCs. Instead, its effect on T cell immunity in vivo may involve CD11b+F4/80+ or other C5aR-expressing leukocytes. Further, our data reveal a surprising role of the 3′UTR of C5aR mRNA in regulating C5aR protein targeting to the plasma membrane.
This study was conducted to evaluate the effectiveness and safety of intensity-modulated radiotherapy (IMRT) and concurrent paclitaxel plus cisplatin (TP regimen) for upper esophageal carcinoma.
36 patients of upper esophageal carcinoma were retrospectively analyzed. Patients were treated with IMRT (median 60 Gy) combined with concurrent TP regimen chemotherapy. The Kaplan-Meier analysis was performed in statistical analysis. Toxicities were recorded according to the NCI CTC version 3.0.
36 patients aged 43–73 years (median 57 years). The median follow-up period was 14.0 months. The 1-year and 2-year survival rates were 83.3% and 42.8% respectively. The median progression-free survival (PFS) time and overall survival (OS) time were 12.0 (95% CI: 7.8–16.2 months) and 18.0 months (95% CI: 9.9–26.1 months), respectively. Grade 3 neutropenia, radiation-induced esophagitis and radiodermatitis were observed in 5 (13.9%), 3 (8.3%) and 8 (22.2%) patients respectively. There were two treatment-related deaths due to esophageal perforation and hemorrhea.
For those patients with upper esophageal carcinoma, IMRT combined with concurrent TP regimen chemotherapy was an effective treatment. However, more attention should be paid to the occurrence of perforation and hemorrhea.
Upper esophageal carcinoma; Paclitaxel; Cisplatin; Intensity-modulated radiotherapy
The search for a strategy to provide temporary liver support and salvage the patients with acute-on-chronic liver failure (ACLF) remains an important issue. This study was designed to evaluate the experience in artificial liver support system (ALSS) combined with liver transplantation (LT) in the treatment of ACLF.
One hundred and seventy one patients with HBV related ACLF undergoing LT between January 2001 and December 2009 were included. Of the 171 patients, 115 received 247 sessions of plasma exchange-centered ALSS treatment prior to LT (ALSS-LT group) and the other 56 received emergency LT (LT group). The MELD score were 31±6 and 30±7 in ALSS-LT group and LT group. ALSS treatment resulted in improvement of liver function and better tolerance to LT. The average level of serum total bilirubin before LT was lower than that before the first time of ALSS treatment. The median waiting time for a donor liver was 12 days (2–226 days) from the first run of ALSS treatment to LT. Compared to LT group, the beneficial influences of ALSS on intraoperative blood loss and endotracheal intubation time were also observed in ALSS-LT group. The 1-year and 5-year survival rates in the ALSS-LT group and LT group were 79.2% and 83%, 69.7% and 78.6%.
Plasma exchange-centered ALSS is beneficial in salvaging patients with ACLF when a donor liver is not available. The consequential LT is the fundamental treatment modality to rescue these patients and lead to a similar survival rate as those patients receiving emergency transplantation.
Hepatocellular carcinoma (HCC) is one of the most aggressive malignancies in humans, and its prognosis is generally poor even after surgery. Many advances have been made to understand the pathogenesis of HCC; however, the molecular mechanisms that lead to hepatocarcinogenesis and progression are still not clearly understood.
The expression of DACT2 in specimens from 30 paired HCCs and an additional 61 HCC patients after liver transplantation was evaluated by quantitative RT-PCR and immunohistochemical analysis. We investigated the methylation status of the DACT2 promoter region. We also analyzed the alterations of the cell cycle, migration and invasion after DACT2 knockdown.
The expression level of DACT2 was significantly lower in HCC tissues than in non-cancerous tissues. Reduced DACT2 expression was associated with large tumor size. DACT2 transcripts were at low levels in hypermethylated liver cancer cells and were restored by exposure to a demethylating agent. Reduced expression of DACT2 in MHCC97L cells induced G1/S arrest, increased cell proliferation, and promoted cell invasion.
Our study suggests that DACT2 is silenced by promoter hypermethylation, and reduced DACT2 can promote liver cancer progression. DACT2 may serve as a novel tumor suppressor gene in HCC.
DACT2; Hepatocellular carcinoma; Methylation; Progression
Chemotherapy regiments have been widely used in the treatment of a variety of human malignancies including hepatocellular carcinoma (HCC). A major cause of failure in chemotherapy is drug resistance of cancer cells. Resistance to doxorubicin (DOX) is a common and representative obstacle to treat cancer effectively. Individual microRNA (miRNA) has been introduced in the evolution of DOX resistance in HCC in recent studies. However, a global and systematic assessment of the miRNA expression profiles contributing to DOX resistance is still lacking. In the present study, we applied high-throughput Illumina sequencing to comprehensively characterize miRNA expression profiles in both human HCC cell line (HepG2) and its DOX-resistant counterpart (HepG2/DOX). A total of 269 known miRNAs were significantly differentially expressed, of which 23 were up-regulated and 246 were down-regulated in HepG2/DOX cells, indicating that part of them might be involved in the development of DOX resistance. In addition, we have identified 9 and 13 novel miRNAs up- and down-expressed significantly in HepG2/DOX cells, respectively. miRNA profiling was then validated by quantitative real-time PCR for selected miRNAs, including 22 known miRNAs and 6 novel miRNAs. Furthermore, we predicted the putative target genes for the deregulated miRNAs in the samples. Function annotation implied that these selected miRNAs affected many target genes mainly involved in MAPK signaling pathway. This study provides us a general description of miRNA expression profiling, which is helpful to find potential miRNAs for adjunct treatment to overcome DOX resistance in future HCC chemotherapy.
Objective: Single-nucleotide polymorphisms (SNPs) in Cytotoxic T lymphocyte antigen 4 (CTLA-4) gene have been detected and proved to associate with the incidence of rejection after transplantation. However, previous studies gained inconsistent results about the association between CTLA-4 +49 single-nucleotide polymorphism and susceptibility of allograft rejection. Therefore we sought to clarify whether CTLA-4 +49 SNP influences the incidence of acute rejection after liver transplantation in Chinese population. Methods: Genomic DNA from 335 liver transplant recipients was genotyped for CTLA-4 +49 SNP by DNA sequencing. Acute rejection was confirmed by pathologic evidences. The association between CTLA-4 +49 SNP and incidence of acute rejection was then analyzed by dominant, recessive, codominant and overdominant models. Results: The incidence of acute rejection within the first 3 months was 11.9%. In acute rejectors, the frequency was 45% for G/G, 10% for A/A and 45% for A/G respectively, compared with 47.5% for G/G, 10.8% for A/A and 41.7% for A/G in non-acute rejectors. And no significant difference of allele distribution between these 2 groups was detected. Conclusions: This study suggests that CTLA-4 +49 SNP is not associated with acute rejection after liver transplantation in Chinese population.
Cytotoxic T lymphocyte antigen 4; liver transplantation; Single Nucleotide Polymorphism.