Effects of low level laser on periodontal tissue remodeling in hPDLCs under tensile stress.

This study aimed to investigate the effect of Low-Level Laser Therapy (LLLT) on human Periodontal Ligament Cells (hPDLCs) under tension stress. Primary hPDLCs were obtained using the tissue culture method, and P3 cells were utilized for the subsequent experiments. The study comprised four groups: a blank control group (Group B), a laser irradiation group (Group L), a tension stress group (Group T), and a laser + tension stress group (Group LT). Mechanical loading was applied using an in-vitro cell stress loading device at a frequency of 0.5 Hz and deformation of 2% for two hours per day for two days. Laser irradiation at 808 nm GaAlAs laser was administered 1 h after force loading. Cell samples were collected after the experiment. Bone and fiber remodeling factors were analyzed using PCR and Western blot. Flow cytometry was employed to assess the cell cycle, while ROS and Ca2+ levels were measured using a multifunctional enzyme labeling instrument. The results revealed that laser intervention under tension stress inhibited the expression of osteogenic differentiation factors, promoted the expression of osteoclast differentiation factors, and significantly increased the production of collagen factors, MMPs, and TIMPs. The LT group exhibited the most active cell cycle (P < 0.05). LLLT not only enhanced Ca2+ expression in hPDLCs under tension stress, but also stimulated the production of ROS. Overall, our findings demonstrate that LLLT effectively accelerated the proliferation of hPDLCs and the remodeling of periodontal tissue, possibly through the regulation of ROS and Ca2+ levels in hPDLCs.

Tctex-1, a novel interaction partner of Kidney Injury Molecule-1, is required for efferocytosis.

Kidney injury molecule-1 (KIM-1) is a phosphatidylserine receptor that is specifically upregulated on proximal tubular epithelial cells (PTECs) during acute kidney injury and mitigates tissue damage by mediating efferocytosis (the phagocytic clearance of apoptotic cells). The signaling molecules that regulate efferocytosis in TECs are not well understood. Using a yeast two-hybrid screen, we identified the dynein light chain protein, Tctex-1, as a novel KIM-1-interacting protein. Immunoprecipitation and confocal imaging studies suggested that Tctex-1 associates with KIM-1 in cells at baseline, but, dissociates from KIM-1 within 90 min of initiation of efferocytosis. Interfering with actin or microtubule polymerization interestingly prevented the dissociation of KIM-1 from Tctex-1. Moreover, the subcellular localization of Tctex-1 changed from being microtubule-associated to mainly cytosolic upon expression of KIM-1. Short hairpin RNA-mediated silencing of endogenous Tctex-1 in cells significantly inhibited efferocytosis to levels comparable to that of knock down of KIM-1 in the same cells. Importantly, Tctex-1 was not involved in the delivery of KIM-1 to the cell-surface. On the other hand, KIM-1 expression significantly inhibited the phosphorylation of Tctex-1 at threonine 94 (T94), a post-translational modification which is known to disrupt the binding of Tctex-1 to dynein on microtubules. In keeping with this, we found that KIM-1 bound less efficiently to the phosphomimic (T94E) mutant of Tctex-1 compared to wild type Tctex-1. Surprisingly, expression of Tctex-1 T94E did not influence KIM-1-mediated efferocytosis. Our studies uncover a previously unknown role for Tctex-1 in KIM-1-dependent efferocytosis in epithelial cells.

Donor kidney injury molecule-1 promotes graft recovery by regulating systemic necroinflammation.

Ischemia-reperfusion injury during kidney transplantation predisposes to delayed graft function, rejection, and premature graft failure. Exacerbation of tissue damage and alloimmune responses may be explained by necroinflammation: an autoamplification loop of cell death and inflammation, which is mediated by the release of damage-associated molecular patterns (eg, high-mobility group box-1; HMGB1) from necrotic cells that activate both innate and adaptive immune pathways. Kidney injury molecule-1 (KIM-1) is a phosphatidylserine receptor that is upregulated on injured proximal tubular epithelial cells and enables them to clear apoptotic and necrotic cells. Here we show a pivotal role for clearance of dying cells in regulating necroinflammation in a syngeneic murine kidney transplant model. We found persistent KIM-1 expression in KIM-1+/+ kidney grafts posttransplantation. Compared to recipients of KIM-1+/+ kidneys, recipients of KIM-1-/- kidneys exhibited significantly more renal dysfunction, apoptosis and necrosis, tubular obstruction, and graft failure. KIM-1-/- grafts also had more inflammatory cytokines, infiltrating neutrophils, and macrophages compared to KIM-1+/+ grafts. Most significantly, passive release of HMGB1 from apoptotic and necrotic cells led to dramatically higher serum HMGB1 levels and increased proinflammatory macrophages in recipients of KIM-1-/- grafts. Our data identify an endogenous protective mechanism against necroinflammation in kidney grafts that may be of therapeutic relevance in transplantation.

The comprehensive liver transcriptome of two cattle breeds with different intramuscular fat content.

Intramuscular fat (IMF) content is an important determinant factor of meat quality in cattle. There is significant difference in IMF content between Jinnan and Simmental cattle. Here, to identify candidate genes and networks associated with IMF deposition, we deeply explored the transcriptome architecture of liver in these two cattle breeds. We sequenced the liver transcriptome of five Jinnan and three Simmental cattle, yielding about 413.9 million sequencing reads. 124 differentially expressed genes (DEGs) were detected, of which 53 were up-regulated and 71 were down-regulated in Jinnan cattle. 1282 potentially novel genes were also identified. Gene ontology analysis revealed these DEGs (including CYP21A2, PC, ACACB, APOA1, and FADS2) were significantly enriched in lipid biosynthetic process, regulation of cholesterol esterification, reverse cholesterol transport, and regulation of lipoprotein lipase activity. Genes involved in pyruvate metabolism pathway were also significantly overrepresented. Moreover, we identified an interaction network which related to lipid metabolism, which might be contributed to the IMF deposition in cattle. We concluded that the DEGs involved in the regulation of lipid metabolism could play an important role in IMF deposition. Overall, we proposed a new panel of candidate genes and interaction networks that can be associated with IMF deposition and used as biomarkers in cattle breeding.

Application of esophageal irradiation stents coated with 125I particles in advanced esophageal cancer.

PURPOSE: The current study was designed to investigate the primary efficacy of esophageal irradiation stents coated with 125I particles in the treatment of elderly patients with advanced esophageal cancer. METHODS: Forty-three elderly patients with advanced esophageal cancer were treated with esophageal stents in the First Affiliated Hospital of Xinxiang Medical University between September 2009 and December 2010. Patients were randomly divided into group A (N=18), treated with irradiation stents, and group B (N=25), treated with ordinary stents. There were no significant intergroup differences in age, lesion length, degree of stenosis, or cancer stage. The stent implantation success rate, relief of dysphagia and complication rate, and survival were assessed. RESULTS: The stent implantation success and short-term dysphagia relief rates were 100.0% in both groups. The mean survival time was 9.8 months and 4.8 months in groups A and B, respectively (p<0.01). However, no significant difference in pain (5/18) or esophageal restenosis (7/25) was found (both p>0.05). CONCLUSION: Dysphagia was relieved and survival was prolonged in advanced esophageal cancer cases treated with 125I particle-coated esophageal stents. This method may be superior to the traditional stents method.

G protein α12 (Gα12) is a negative regulator of kidney injury molecule-1-mediated efferocytosis.

Kidney injury molecule-1 (KIM-1) is a receptor for the "eat me" signal, phosphatidylserine, on apoptotic cells. The specific upregulation of KIM-1 by injured tubular epithelial cells (TECs) enables them to clear apoptotic cells (also known as efferocytosis), thereby protecting from acute kidney injury. Recently, we uncovered that KIM-1 binds directly to the α-subunit of heterotrimeric G12 protein (Gα12) and inhibits its activation by reactive oxygen species during renal ischemia-reperfusion injury (Ismail OZ, Zhang X, Wei J, Haig A, Denker BM, Suri RS, Sener A, Gunaratnam L. Am J Pathol 185: 1207-1215, 2015). Here, we investigated the role that Gα12 plays in KIM-1-mediated efferocytosis by TECs. We showed that KIM-1 remains bound to Gα12 and suppresses its activity during phagocytosis. When we silenced Gα12 expression using small interefering RNA, KIM-1-mediated engulfment of apoptotic cells was increased significantly; in contrast overexpression of constitutively active Gα12 (QLGα12) resulted in inhibition of efferocytosis. Inhibition of RhoA, a key effector of Gα12, using a chemical inhibitor or expression of dominant-negative RhoA, had the same effect as inhibition of Gα12 on efferocytosis. Consistent with this, silencing Gα12 suppressed active RhoA in KIM-1-expressing cells. Finally, using primary TECs from Kim-1+/+ and Kim-1-/- mice, we confirmed that engulfment of apoptotic cells requires KIM-1 expression and that silencing Gα12 enhanced efferocytosis by primary TECs. Our data reveal a previously unknown role for Gα12 in regulating efferocytosis and that renal TECs require KIM-1 to mediate this process. These results may have therapeutic implications given the known harmful role of Gα12 in acute kidney injury.

Kidney injury molecule-1 protects against Gα12 activation and tissue damage in renal ischemia-reperfusion injury.

Ischemic acute kidney injury is a serious untreatable condition. Activation of the G protein α12 (Gα12) subunit by reactive oxygen species is a major cause of tissue damage during renal ischemia-reperfusion injury. Kidney injury molecule-1 (KIM-1) is a transmembrane glycoprotein that is highly up-regulated during acute kidney injury, but the physiologic significance of this up-regulation is unclear. Here, we report for the first time that Kim-1 inhibits Gα12 activation and protects mice against renal ischemia-reperfusion injury. We reveal that Kim-1 physically interacts with and inhibits cellular Gα12 activation after inflammatory stimuli, including reactive oxygen species, by blocking GTP binding to Gα12. Compared with Kim-1(+/+) mice, Kim-1(-/-) mice exhibited greater Gα12 and downstream Src activation both in primary tubular epithelial cells after in vitro stimulation with H2O2 and in whole kidneys after unilateral renal artery clamping. Finally, we show that Kim-1-deficient mice had more severe kidney dysfunction and tissue damage after bilateral renal artery clamping, compared with wild-type mice. Our results suggest that KIM-1 is an endogenous protective mechanism against renal ischemia-reperfusion injury through inhibition of Gα12.

Accelerated receptor shedding inhibits kidney injury molecule-1 (KIM-1)-mediated efferocytosis.

Efficient clearance of apoptotic cells (efferocytosis) prevents inflammation and permits repair following tissue injury. Kidney injury molecule-1 (KIM-1) is a receptor for phosphatidylserine, an "eat-me" signal exposed on the surface of apoptotic cells that marks them for phagocytic clearance. KIM-1 is upregulated on proximal tubule epithelial cells (PTECs) during ischemic acute kidney injury (AKI), enabling efferocytosis by surviving PTECs. KIM-1 is spontaneously cleaved at its ectodomain region to generate a soluble fragment that serves a sensitive and specific biomarker for AKI, but the biological relevance of KIM-1 shedding is unknown. Here, we sought to determine how KIM-1 shedding might regulate efferocytosis. Using cells that endogenously and exogenously express KIM-1, we found that hydrogen peroxide-mediated oxidative injury or PMA treatment accelerated KIM-1 shedding in a dose-dependent manner. KIM-1 shedding was also accelerated when apoptotic cells were added. Accelerated shedding or the presence of excess soluble KIM-1 in the extracellular milieu significantly inhibited efferocytosis. We also identified that TNF-α-converting enzyme (TACE or ADAM17) mediates both the spontaneous and PMA-accelerated shedding of KIM-1. While accelerated shedding inhibited efferocytosis, we found that spontaneous KIM-1 cleavage does not affect the phagocytic efficiency of PTECs. Our results suggest that KIM-1 shedding is accelerated by worsening cellular injury, and excess soluble KIM-1 competitively inhibits efferocytosis. These findings may be important in AKI when there is severe cellular injury.

Anchorage effects of ligation and direct occlusion in orthodontics: A finite element analysis.

BACKGROUND AND OBJECTIVE: During orthodontic treatment, the figure-of-eight ligature and the physiological occlusion play an important role in providing anchorage effects. However, their effects on reaction forces of tooth and stress state in periodontal ligament (PDL) have not been quantitatively evaluated yet. In this study, we presented a finite element analysis process for simulating posterior molar ligature and direct occlusion during orthodontics in order to quantitatively assess their anchorage effects. METHODS: A high precision 3D biomechanical model containing upper and lower teeth, PDL, brackets and archwire was generated from the images of computed tomographic scan and sophisticated modelling procedures. The orthodontic treatment of closing the extraction gap was simulated via the finite element method to evaluate the biomechanical response of the molars under the conditions with or without ligation. The simulations were divided into experimental and control groups. In the experimental group, orthodontic force of 1 N was first applied, then direct occlusal forces of 3 and 10 N were applied on each opposite tooth. While in the control group, occlusal forces were applied without orthodontic treatment. The tooth displacement, the stress state in the PDL and the directions of the resultant forces on each tooth were evaluated. RESULTS: In the case of molars ligated, the maximum hydrostatic stress in the molars' PDL decreases by 60%. When an initial tooth displacement of several microns occurs in response to an orthodontic force, the direction of the occlusal force changes simultaneously. Even a moderate occlusal force (3 N per tooth) can almost completely offset the mesial forces on the maxillary teeth, thus to provide effective anchorage effect for the orthodontics. CONCLUSIONS: The proposed method is effective for simulating ligation and direct occlusion. Figure-of-eight ligature can effectively disperse orthodontic forces on the posterior teeth, while a good original occlusal relationship provides considerable anchorage effects in orthodontics.

Cellular magnetic resonance imaging of monocyte-derived dendritic cell migration from healthy donors and cancer patients as assessed in a scid mouse model.

BACKGROUND AIMS. The use of dendritic cells (DC) as an adjuvant in cell-based immunotherapeutic cancer vaccines is a growing field of interest. A reliable and non-invasive method to track the fate of autologous DC following their administration to patients is required in order to confirm that clinically sufficient numbers are reaching the lymph node (LN). We demonstrate that an immunocompromised mouse model can be used to conduct translational studies employing cellular magnetic resonance imaging (MRI). Such studies can provide clinically relevant information regarding the migration potential of clinical-grade DC used in cancer immunotherapies. METHODS. Human monocyte-derived dendritic cells (mo-DC) were generated from negatively selected monocytes obtained from either healthy donors or cancer patients. DC were labeled with superparamagnetic iron oxide (SPIO) nanoparticles in order to track them in vivo in a CB17scid mouse model using cellular MRI. SPIO did not have any adverse effects on DC phenotype or function, independent of donor type. Cellular MRI readily detected migration of SPIO-loaded DC in CB17scid mice. No differences in migration were observed between DC obtained from healthy donors and those obtained from donors undergoing autologous stem cell transplant for cancer therapy. CONCLUSIONS. Cellular MRI provided semi-quantitative image data that corresponded with data obtained by digital morphometry, validating cellular MRI's potential to assess DC migration in DC-based cancer immunotherapy clinical trials.

Mucosally delivered dendritic cells activate T cells independently of IL-12 and endogenous APCs.

In vitro manipulated dendritic cells (DC) have increasingly been used as a promising vaccine formulation against cancer and infectious disease. However, improved understanding of the immune mechanisms is needed for the development of safe and efficacious mucosal DC immunization. We have developed a murine model of respiratory mucosal immunization by using a genetically manipulated DC vaccine. Within 24 h of intranasal delivery, the majority of vaccine DCs migrated to the lung mucosa and draining lymph nodes and elicited a significant level of T cells capable of IFN-gamma secretion and CTL in the airway lumen as well as substantial T cell responses in the spleen. And such T cell responses were associated with enhanced protection against respiratory mucosal intracellular bacterial challenge. In comparison, parenteral i.m. DC immunization did not elicit marked airway luminal T cell responses and immune protection regardless of strong systemic T cell activation. Although repeated mucosal DC delivery boosted Ag-specific T cells in the airway lumen, added benefits to CD8 T cell activation and immune protection were not observed. By using MHC-deficient vaccine DCs, we further demonstrated that mucosal DC immunization-mediated CD8 and CD4 T cell activation does not require endogenous DCs. By using IL-12-deficient vaccine DCs, we also observed that IL-12(-/-) DCs failed to migrate to the lymph nodes but remained capable of T cell activation. Our observations indicate that mucosal delivery of vaccine DCs represents an effective approach to enhance mucosal T cell immunity, which may operate independent of vaccine IL-12 and endogenous DCs.

Airway delivery of soluble mycobacterial antigens restores protective mucosal immunity by single intramuscular plasmid DNA tuberculosis vaccination: role of proinflammatory signals in the lung.

Protection by parenteral immunization with plasmid DNA vaccines against pulmonary tuberculosis (TB) is very modest. In this study, we have investigated the underlying mechanisms for the poor mucosal protective efficacy and the avenues and mechanisms to improve the efficacy of a single i.m. immunization with a monogenic plasmid DNA TB vaccine in a murine model. We show that i.m. DNA immunization fails to elicit accumulation of Ag-specific T cells in the airway lumen despite robust T cell responses in the spleen. Such systemically activated T cells cannot be rapidly mobilized into the airway lumen upon Mycobacterium tuberculosis exposure. However, airway deposition of low doses of soluble mycobacterial Ags in previously immunized mice effectively mobilizes the systemically activated T cells into the airway lumen. A fraction of such airway luminal T cells can persist in the airway lumen, undergo quick, robust expansion and activation and provide marked immune protection upon airway M. tuberculosis exposure. Airway mucosal deposition of soluble mycobacterial Ags was found to create a tissue microenvironment rich in proinflammatory molecules including chemokines and hence conducive to T cell recruitment. Thus, in vivo neutralization of MIP-1alpha or IFN-inducible protein-10 markedly inhibited the accumulation of Ag-specific T cells in the airway lumen. Our data suggest that immunoprotective efficacy on the mucosal surface by i.m. plasmid DNA immunization could be substantially improved by simple mucosal soluble Ag inoculation and restoration of mucosal luminal T cells. Our study holds implication for the future design of DNA vaccination strategies against intracellular infections.

Immunization with a bivalent adenovirus-vectored tuberculosis vaccine provides markedly improved protection over its monovalent counterpart against pulmonary tuberculosis.

Recombinant virus-vectored vaccines hold great promise for tuberculosis (TB) vaccination strategies. However, there is a lack of side-by-side comparative investigations to dissect the functional differences and support the advantage of multivalent virus-vectored vaccine over its monovalent counterpart. We previously successfully developed a monovalent adenovirus (Ad)-vectored vaccine expressing Ag85a (AdAg85a) and demonstrated its superior protective efficacy in models of pulmonary TB. In this study, we have developed a bivalent Ad TB vaccine expressing Ag85a and TB10.4 antigens as a fusion protein (AdAg85a:TB10.4) and compared its T-cell-activating and immune protective efficacy with that by monovalent AdAg85a. A single intranasal (i.n.) administration of AdAg85a:TB10.4 induced robust T-cell responses toward the respective antigens within the airway lumen and spleen, although the level of Ag85a-specific T-cell responses in the airway lumen triggered by bivalent AdAg85a:TB10.4 was lower than that by its monovalent counterpart at earlier time points. Thus, a single i.n. delivery of AdAg85a:TB10.4 conferred a markedly improved and sustained level of protection in the lung against Mycobacterium tuberculosis (M.tb) challenge over that by AdAg85a or by conventional BCG immunization with similarly induced levels of protection in the spleen. Our results indicate a unique advantage of multivalent viral-vectored TB vaccines for immunization against pulmonary TB.

Heterologous boosting of recombinant adenoviral prime immunization with a novel vesicular stomatitis virus-vectored tuberculosis vaccine.

Pulmonary tuberculosis (TB) remains a serious health problem worldwide. Effective vaccination strategies are needed. We report the development of a novel TB vaccine using vesicular stomatitis virus (VSV) as a viral vector system to express Ag85A. VSVAg85A was shown to be immunogenic when given to mice by either an intranasal or an intramuscular (i.m.) route. Although distinct T-cell profiles resulted from both routes of immunization, only intranasal delivery generated a mucosal T-cell response that was protective upon pulmonary Mycobacterium tuberculosis (M.tb) challenge. While this protection manifested at an early time-point after immunization, it was not sustained. The potential of VSVAg85A to be used as a mucosal booster for parenteral priming by an adenoviral TB vaccine expressing Ag85A (AdAg85A) was investigated. VSVAg85A immunization markedly boosted antigen-specific T-cell responses in the airway lumen while also augmenting immune activation in the systemic compartment, after AdAg85A priming. This translated into significantly better protective efficacy against pulmonary challenge with M.tb than either vaccine used alone. Our study therefore suggests that VSV as a vector system is a promising candidate to be used in a heterologous viral prime-boost immunization regimen against intracellular bacterial infection.

Organ distribution of transgene expression following intranasal mucosal delivery of recombinant replication-defective adenovirus gene transfer vector.

It is believed that respiratory mucosal immunization triggers more effective immune protection than parenteral immunization against respiratory infection caused by viruses and intracellular bacteria. Such understanding has led to the successful implementation of intranasal immunization in humans with a live cold-adapted flu virus vaccine. Furthermore there has been an interest in developing effective mucosal-deliverable genetic vaccines against other infectious diseases. However, there is a concern that intranasally delivered recombinant viral-based vaccines may disseminate to the CNS via the olfactory tissue. Initial experimental evidence suggests that intranasally delivered recombinant adenoviral gene transfer vector may transport to the olfactory bulb. However, there is a lack of quantitative studies to compare the relative amounts of transgene products in the respiratory tract, lung, olfactory bulb and brain after intranasal mucosal delivery of viral gene transfer vector. To address this issue, we have used fluorescence macroscopic imaging, luciferase quantification and PCR approaches to compare the relative distribution of transgene products or adenoviral gene sequences in the respiratory tract, lung, draining lymph nodes, olfactory bulb, brain and spleen. Intranasal mucosal delivery of replication-defective recombinant adenoviral vector results in gene transfer predominantly in the respiratory system including the lung while it does lead to a moderate level of gene transfer in the olfactory bulb. However, intranasal inoculation of adenoviral vector leads to little or no viral dissemination to the major region of the CNS, the brain. These experimental findings support the efficaciousness of intranasal adenoviral-mediated gene transfer for the purpose of mucosal immunization and suggest that it may not be of significant safety concern.

Apoptosis inhibitor of macrophage protein enhances intraluminal debris clearance and ameliorates acute kidney injury in mice.

Acute kidney injury (AKI) is associated with prolonged hospitalization and high mortality, and it predisposes individuals to chronic kidney disease. To date, no effective AKI treatments have been established. Here we show that the apoptosis inhibitor of macrophage (AIM) protein on intraluminal debris interacts with kidney injury molecule (KIM)-1 and promotes recovery from AKI. During AKI, the concentration of AIM increases in the urine, and AIM accumulates on necrotic cell debris within the kidney proximal tubules. The AIM present in this cellular debris binds to KIM-1, which is expressed on injured tubular epithelial cells, and enhances the phagocytic removal of the debris by the epithelial cells, thus contributing to kidney tissue repair. When subjected to ischemia-reperfusion (IR)-induced AKI, AIM-deficient mice exhibited abrogated debris clearance and persistent renal inflammation, resulting in higher mortality than wild-type (WT) mice due to progressive renal dysfunction. Treatment of mice with IR-induced AKI using recombinant AIM resulted in the removal of the debris, thereby ameliorating renal pathology. We observed this effect in both AIM-deficient and WT mice, but not in KIM-1-deficient mice. Our findings provide a basis for the development of potentially novel therapies for AKI.

MicroRNA-194 acts as a prognostic marker and inhibits proliferation in hepatocellular carcinoma by targeting MAP4K4.

MicroRNAs (miRNAs) play a crucial role in cancer development and progression of hepatocellular carcinoma (HCC). In this study, we aimed to analyze the role of microRNA-194 (miR-194) in HCC. We found that miR-194 expression was significantly reduced in HCC and its expression was an independent poor prognostic factor for HCC patient overall and disease-free survival rate. A significant correlation was observed between miR-194 reduction and unfavourable variables including tumor size (P = 0.0315), histologic grade (P = 0.0038), TNM stage (P = 0.0083), intrahepatic metastasis (P = 0.0184). Overexpression of miR-194 in HCC cell lines HepG2 and Hep3B inhibited cell proliferation by blocking G1-S transition and inducing apoptosis. Mitogen-activated protein kinase 4 (MAP4K4), a potential target gene of miR-194, was inversely correlated with miR-194 expression in HCC tissues and cell lines. Further studies demonstrated that miR-194 regulated the progression of HCC through directly inhibiting the expression of MAP4K4 and the restoration of MAP4K4 expression reversed the inhibitory effects of miR-194 on HCC cell proliferation. Together, our findings indicate that miR-194 may serve as a valuable prognostic marker and promising interventional therapeutic target for HCC.

Down-regulation of Rab17 promotes tumourigenic properties of hepatocellular carcinoma cells via Erk pathway.

The small GTPase, Ras-related protein 17 (Rab17), a member of the Rab family, plays a critical role in the regulation of membrane traffic in polarized eukaryotic cells. However, the role of Rab17 in hepatocellular carcinoma (HCC) is not clear. Clinical speciments reveal that Rab17 was present in 15 of 20 (75.0%) paraneoplastic tissues and 7 of 20 (35.0%) HCC samples (P=0.0248). To elucidate the tumourigenic role of Rab17 in HCC, we generated two Rab17 low-expressing HCC cell lines (Hep3B and Huh-7). The results showed that Rab17 down-regulation significantly promoted the tumourigenic properties of HCC cells in vitro and in vivo, as demonstrated by enhanced cell proliferation, colony formation, invasion and migration, decreased G1 arrest, and increased tumour xenograft growth and angiogenesis. However, the enhanced tumourigenic properties of HCC cells by Rab17 down-regulation was significantly inhibited by PD980592, the inhibitor of the Erk pathway, indicating that the Erk pathway plays a critical role in Rab17 down-regulation-induced enhanced tumourigenic properties of HCC cells. Our data provide a new insight into the essential role of Rab17 in HCC carcinogenesis and suggest that Rab17 expression might be tumor suppressor gene and might provide a new interventional therapeutic target for this common malignancy.

Cyclooxygenase-2 inhibitor celecoxib inhibits promotion of mammary tumorigenesis in rats fed a high fat diet rich in n-6 polyunsaturated fatty acids.

The objective of this investigation was to determine whether celecoxib, a highly specific inhibitor of cyclooxygenase-2 (COX-2), inhibits the promotion phase of mammary tumorigenesis in rats fed a high fat diet rich in n-6 polyunsaturated fatty acids (PUFAs) that is known to induce COX-2 expression. Sixty female Sprague-Dawley rats were initially maintained on an AIN-93G diet. At 50 days of age they received a single i.p. injection of methylnitrosourea (MNU). One week later, all rats were switched to a modified AIN-93G diet containing 18% safflower oil plus 3% soybean oil. Half of the rats also began receiving 1500 ppm celecoxib in the diet and the control and experimental diets were continued for a further 23 weeks. Celecoxib significantly decreased both the final tumor incidence (63.3% in the celecoxib group versus 82.2% in the control group, P<0.05) and tumor multiplicity (0.9+/-0.2 tumors/rat in the celecoxib group versus 2.3+/-0.3 tumors/rat in the control group, P<0.05). At the termination of the experiment, body weights were significantly lower in the celecoxib group compared to controls (330.6+/-6.1 versus 401.5+/-10.9 g respectively, P<0.05) although there was no evidence of toxicity and food intakes were not different for the two groups. Fasting serum triglycerides and abdominal adipose tissue accumulation were lower in the celecoxib group compared to controls (49.3+/-4.4 versus 82.8+/-12.6 mg/dL, P<0.05, and 7.2+/-0.3 versus 11.3+/-0.4% of body weight, P<0.01, respectively). These results show that administration of celecoxib to rats in a high fat diet rich in n-6 PUFAs suppresses the promotion of mammary tumorigenesis induced by MNU. This inhibition may be due to the effects of celecoxib on lipid metabolism as well as COX-2.

[The effect of vitamin C in oxidative modification of low-density lipoprotein induced by macrophage and copperion].

OBJECTIVE: To study the effect of vitamin C on preventing oxidative modification of low density lipoprotein cholesterol (LDL) in vitro. METHODS: Different levels of vitamin C were added to two different systems of lipid peroxidation of LDL induced by either Cu(2+) or macrophage. The level of VC in systems induced by Cu(2+) were 10, 50, 100 and 200 micromol/L respectively and by macrophage were 50, 100, 200 micromol/L respectively. Vitamin E (200 micromol/L) and VC(0) (0 micromol/L) were served as positive and negative control respectively. The content of TBARS, Ox-LDL, fluorescent compounds, electrophoretic mobility of LDL and the lag-phage of oxidation of LDL were measured. RESULTS: In the oxidative systems induced by Cu(2+), the groups with higher levels of VC (100, 200 micromol/L) reduced the levels of TBARS, Ox-LDL at 3, 6, and 9 hour after adding Cu(2+), but low dose groups (10, 50 micromol/L) had no the effects. In the macrophage systems, higher levels of VC (100, 200 micromol/L) significantly reduced levels of fluorescent compounds and TBARS, and also lowered electrophoretic mobility of LDL and increased the lag-phage of oxidation of LDL. CONCLUSION: Vitamin C has dual effect on oxidation of LDL. Low dose treatment enhanced oxidation of LDL, but high doses has anti-oxidative effects on LDL.