Exosome biogenesis: machinery, regulation, and therapeutic implications in cancer.

Exosomes are well-known key mediators of intercellular communication and contribute to various physiological and pathological processes. Their biogenesis involves four key steps, including cargo sorting, MVB formation and maturation, transport of MVBs, and MVB fusion with the plasma membrane. Each process is modulated through the competition or coordination of multiple mechanisms, whereby diverse repertoires of molecular cargos are sorted into distinct subpopulations of exosomes, resulting in the high heterogeneity of exosomes. Intriguingly, cancer cells exploit various strategies, such as aberrant gene expression, posttranslational modifications, and altered signaling pathways, to regulate the biogenesis, composition, and eventually functions of exosomes to promote cancer progression. Therefore, exosome biogenesis-targeted therapy is being actively explored. In this review, we systematically summarize recent progress in understanding the machinery of exosome biogenesis and how it is regulated in the context of cancer. In particular, we highlight pharmacological targeting of exosome biogenesis as a promising cancer therapeutic strategy.

Effect of combined treatment with cyclophosphamidum and allicin on neuroblastoma-bearing mice.

OBJECTIVE: To evaluate the efficacy of allicin combined with cyclophosphamide on neuroblastoma (NB)-bearing mice and explore the immunological mechanism in it. METHODS: A total of 30 NB-bearing mice were equally randomized into model group, cyclophosphamide group and combined therapy group, 10 nudemice were set as normal saline (NS) group. Cyclophosphamide group and combined therapy group were weekly injected with 60 mg/kg cyclophosphamide for four weeks; besides, combined therapy group was given with allicin (10 mg/kg/d) by gastric perfusion for 4 weeks; model group and NS group were given with the same volume of NS. Serum VEGF content was detected by ELISA pre-treating (0 d) and on the 3rd d, 14th d and 28th d; on 29th d, all mice were sacrificed and the tumor, liver, spleen and thymic tissues were weighted. Tumors were made into paraffin section for detecting tumor cell apoptosis and proliferation by TUNEL and BrdU method, respectively. Survival curves were drawn by Kaplan-Meier method. RESULTS: After treatment, both treatment groups relieved on viscera indexes, VEGF level, T cell subsets distribution and tumor growth and each index of combined therapy group was better than cyclophosphamide group (P<0.05 or 0.01); only combined therapy group could significantly increase the lifetime of NB-bearing mice (µ (2)=5.667, P=0.017). CONCLUSIONS: Allicin can improve T cell subsets distribution and inhibit VEGF expression through its immunomodulatory activity, thereby improve the efficiency on NB in coordination with cyclophosphamide.

An updated meta-analysis on the association of X-ray repair cross complementing group 1 codon 399 polymorphism with hepatocellular carcinoma risk.

BACKGROUND: A number of studies have reported the association of X-ray repair cross-complementing group 1 (XRCC1) Arg399Gln polymorphism with susceptibility to hepatocellular carcinoma (HCC). However, the results were inconsistent and inconclusive. The aim of this study was to comprehensively explore the association of XRCC1 Arg399Gln variant with HCC risk. MATERIALS AND METHODS: Systematic searches of PubMed, Elsevier, Science Direct, CNKI and Chinese Biomedical Literature Database were performed. Pooled odds ratio (OR) with 95% confidence intervals (CI) was calculated to estimate the strength of association. RESULTS: Overall, we observed an increased HCC risk among subjects carrying XRCC1 codon 399 Gln/Gln, Arg/Gln and Gln/ Gln+Arg/Gln genotypes (OR=1.20, 95%CI: 1.05-1.38, OR=1.16, 95%CI: 1.05-1.28, and OR=1.14, 95%CI: 1.04-1.24, respectively) based on 20 studies including 3374 cases and 4633 controls. In subgroup analysis, we observed an increased risk of XRCC1 codon 399 Gln/Gln, Arg/Gln and Gln/Gln+Arg/Gln polymorphisms for HCC in hospital-based study (OR=1.25, 95%CI: 1.03-1.51, OR=1.21, 95%CI: 1.07-1.36 and OR=1.18, 95%CI: 1.06-1.31, respectively) and in Asian population (OR=1.19, 95%CI: 1.03-1.38, OR=1.17, 95%CI: 1.04-1.30 and OR=1.14, 95%CI: 1.04-1.25, respectively). Limiting the analysis to the studies with controls in agreement with Hardy-Weinberg equilibrium (HWE), we observed an increased HCC risk among Gln/Gln, Arg/Gln and Gln/ Gln+Arg/Gln genotype carriers (OR=1.17, 95%CI: 1.05-1.29, OR=1.12, 95%CI: 1.00-1.25 and OR=1.11, 95%CI: 1.02-1.21, respectively). CONCLUSIONS: This updated meta-analysis results suggest that XRCC1 Arg399Gln variants may contribute to HCC risk. Well-designed studies with larger sample size were required to further verify our findings.

Induction of ER stress protects gastric cancer cells against apoptosis induced by cisplatin and doxorubicin through activation of p38 MAPK.

We investigated the role of endoplasmic reticulum (ER) stress response and p38 MAPK pathways in the resistance of gastric cancer cells to chemotherapy. Pretreatment of the gastric cancer cells with the ER stress inducer drastically decreased the apoptotic rate induced by cisplatin or doxorubicin. Induction of ER stress also led to the activation of p38. Inhibition of p38 activity abrogated the effects of ER stress-induced resistance to apoptosis induced by cisplatin- and doxorubicin treatment. Thus, ER-stress response in gastric cancer cells causes resistance to cisplatin- and doxorubicin-induced apoptosis, and ER-stress induced chemo-resistance can be overcome by blocking p38 activity.

Breviscapine alleviates hepatic injury and inhibits PKC-mRNA and its protein expression in brain-dead BA-Ma mini pigs.

BACKGROUND: Brain-dead donors are the main sources for organ transplantation, but many studies show that brain-death affects the organ's function after transplantation. This study was undertaken to investigate liver injury after brain-death in BA-Ma mini pigs and the protective effects of breviscapine on hepatic function and on PKC-alpha mRNA and its protein expression. METHODS: Fifteen BA-Ma mini pigs were equally divided into 3 groups at random: brain-dead (group B), breviscapine pretreated (group P), and control (group C). The brain-dead model was established by increasing intracranial pressure in a modified, slow and intermittent way. At 3, 6, 12, 18 and 24 hours after the initial brain-death, the levels of serum AST, ALT, TNF-alpha, IL-1beta, and IL-6 were determined. The changes in hepatic tissues were assessed, and the expression of PKC-alpha and PKC-alpha mRNA was detected by immunohistochemistry and RT-PCR, respectively. RESULTS: The levels of AST and ALT in groups B and P began to increase 12 hours after brain-death, while the values in group P were lower than those in group B (P<0.05). The levels of IL-1beta, IL-6, and TNF-alpha in groups B and P at 3, 6, 12 and 18 hours were lower than those in group B (P<0.05). At 6, 12 and 24 hours, the expressions of PKC-alpha mRNA and PKC-alpha protein in group P were lower than those in group B (P<0.05). The degree of injury to hepatic cells in group P was milder than that in group B. CONCLUSIONS: Breviscapine inhibits the degree of PKC-alpha mRNA transcription and its protein translation, decreases the release of inflammatory factors, and thus alleviates hepatic injury during brain-death.

[How brain-dead state affects the hepatic morphology and function of Ba-Ma mini pigs and its mechanism].

OBJECTIVE: To investigate the impact of brain death (BD) on the morphology and function of liver. METHODS: Fifteen Ba-ma minipigs were randomly divided into 3 equal groups: brain death group (Group B) made into BD models by increasing the intracranial pressure; breviscapine pretreatment group (Group P), with breviscapine 2.5 mg x kg(-1) given intravenous drip 1-2 hours after the successful establishment of BD model; and control group (Group C) undergoing operation similar to that in Group B but without increasing the intracranial pressure. 3, 6, 12, 18, and 24 hours after the initial confirmation of BD blood samples were collected from the superior vena cava to detect the serum alanine transaminase (ALT), aspartate transaminase (AST), tumor necrosis factor-alpha (TNF-alpha), interleukin (IL)-1beta, and IL-6, and a piece of liver tissues were collected to undergo light microscopy and electron microscopy, and immunohistochemistry to examine the expression of protein kinase (PKC)-alpha by RT-PCR. RESULTS: The levels of serum ALT and AST of Group B began to increase since 12 h after BD, and were both significantly higher than those of Group C 18 and 24 hours after BD (both P < 0.05). The levels of serum ALT and AST of Group P began to increase since 12 h after BD, and were both significantly lower than those of Group B (both P < 0.05). The levels of serum TNF-alpha, IL-1beta, and IL-6 of Group B and Group P began to increase gradually since 3 h after BD, however, those of Group B were all significantly higher than those of group P (all P < 0.05). PKC-alpha was only expressed in the plasma of a few normal liver cells. The PKC-alpha mRNA and protein levels of Groups B and P began to increase since 6 h after BD, however, those of Group B were all significantly higher than those of Group P (all P < 0.05). Light and electron microscopy showed that only mild edema of liver cells was seen in Group P, and since 12 h after BD swelling of mitochondria, edema of liver cells, etc. were seen in Group B, and the morphologic damages were more severe in Group B. CONCLUSION: Brain death evokes hepatic functional and morphological injuries. PKC-alpha may involve in the mechanism. Breviscapine inhibits the activation of PKC-alpha, thus reducing the damage in liver.

[Binding fistulojejunostomy for the treatment of external pancreatic fistula].

OBJECTIVE: To evaluate the safety and feasibility of binding fistulojejunostomy, a new operative procedure, in the treatment of external pancreatic fistula. METHODS: Eight patients suffering from external pancreatic fistula, 4 males and 4 females, aged 49 (22 approximately 69), underwent binding fistulojejunostomy: 2 cm-length of fistula was isolated and a tube was inserted therein, the jejunum was transected and the distant cut end was everted for the length of 3 cm, the mucosa of the everted jejunum was destroyed with carbolic acid, the everted mucosa of jejunum and the fistula were brought together and sutured with silk, the everted jejunum was then turned back to wrap over the fistula, a silk tie was lopped around the entire circumference of the anastomosis, and lastly, the tube was led out of the abdominal wall. RESULTS: all 8 patients recovered smoothly without pancreatic leakage and other complications. CONCLUSION: Binding fistulojejunostomy is safe and effective for the treatment of external pancreatic fistula.

Protection effect of triptolide to liver injury in rats with severe acute pancreatitis.

BACKGROUND: The high mortality of patients with severe acute pancreatitis (SAP) is due to multiorgan dysfunction. The mechanisms of SAP are still obscure. The aim of this study was to investigate the role of nuclear factor-kappa B (NF-kappaB) activation in rats with SAP associated with liver injury and the protection effect of triptolide against liver injury in rats with SAP. METHODS: Ninety Wistar rats were randomly divided into three groups (n=30 each group): severe acute pancreatitis (group P), treatment with triptolide (group T), and sham operation (group S). SAP models were induced by retrograde injection of 5% sodium taurocholate to the pancreatic duct. After the model was successfully established, no treatment was given to group P. In group T, triptolide (0.05 mg/ml) was injected intraperitoneally (0.2 mg/kg). In group S, the abdominal walls of rats were opened, sutured, but not treated. The rats were sacrificed after operation at 2, 6, and 12 hours, respectively. The serum levels of amylase (AMY), alanine aminotransferase (ALT), tumor necrosis factor-alpha (TNF-alpha) and interleukin-6 (IL-6) were determined at three time points (10 rats for each time point). Liver tissues were obtained to detect the activity of NF-kappaB and to observe their pathological changes with light and electron microscopes. RESULTS: The serum levels of AMY and ALT were higher in groups P and T than in group S. The serum AMY levels were significantly lower in group T than in group P at 12 hours after operation. The serum ALT levels were significantly lower in group T than in group P at 6, 12 hours after operation. At the three time points, the levels of TNF-alpha and IL-6 in groups P and T increased more significantly than in group S. In group T they were decreased more significantly than in group P at the three time points. In groups P and T, NF-kappaB activity in liver tissue increased more significantly than in group S at the three time points. The activity of NF-kappaB was higher in group P than in groups S and T at the three time points. Liver pathological damages were milder in group T than in group P under light and electron microscopes. CONCLUSIONS: NF-kappaB plays an important role in the pathogenesis of liver injury in rats with SAP. Triptolide can reduce pathological damage to the liver. Its mechanism is to inhibit the activity of NF-kappaB and to decrease the release of inflammatory mediators.