TMED2 Induces Cisplatin Resistance in Breast Cancer via Targeting the KEAP1-Nrf2 Pathway.

OBJECTIVE: Cisplatin is the first-line treatment for breast cancer, but it faces challenges of drug resistance. This study investigated new molecular mechanisms underlying cisplatin resistance in breast cancer. METHODS: We analyzed sequencing data from the TCGA database to identify potential associations between transmembrane emp24 protein transport domain containing 2 (TMED2) and breast cancer. Western blotting, real-time PCR, CCK-8, and TUNEL assays were used to measure the effects and molecular mechanism of TMED2 on cisplatin resistance in MCF-7 and MDA-MB-231 cell lines. RESULTS: TMED2 was overexpressed in breast cancer and associated with poor prognosis. TMED2 increased cisplatin resistance in breast cancer cells in vitro via promoting ubiquitination of Kelch-like ECH-associated protein 1 (KEAP1), relieving inhibition of KEAP1 on nuclear factor erythroid 2-related factor 2 (Nrf2), and increasing expression of downstream drug resistance related genes, such as heme oxygenase 1 (HO-1) and NAD (P) H quinone oxidoreductase 1 (NQO1). CONCLUSION: We identified a new molecular mechanism by which TMED2 affects cisplatin resistance in breast cancer. Our results provide theoretical guidance for future clinical applications.

Dysregulated Serum Cytokine Production in Pediatric Patients with ß-Thalassemia Major.

ß-Thalassemia major (ß-TM) is an inherited disorder of hemoglobin (Hb) production, which can cause severe anemia. A compromised immune system has been observed in patients with ß-TM, whereas cytokines have a major role in immune modulation. Interleukin-4 (IL-4), IL-8, IL-13 and transforming growth factor-ß (TGF-ß) are critical in initiating pro-inflammatory responses, and the serum levels of those cytokines may be involved in the pathophysiology of ß-thalassemia (ß-thal). To assess this hypothesis, we studied 23 pediatric patients with ß-TM by measuring serum levels of IL-4, IL-8, IL-13 and TGF-ß, as well as evaluating infection frequency per year, total number of transfusions and serum ferritin (SF) levels, together with age-matched healthy controls. We found that patients with ß-thal had higher IL-8, IL-13 and TGF-ß concentrations than normal controls, whereas markedly decreased serum IL-4 level was documented in patients with ß-TM. Serum IL-4 level of ß-thal patients showed a negative significant correlation with infection frequency, total number of transfusions and SF levels. On the contrary, serum levels of IL-8, IL-13 and TGF-ß exerted a positive relationship with those clinical parameters. Taken together, our study implies that dysregulated cytokine profile might contribute to iron overloads and impair immune cell functions, thus serving as useful biomarkers for diagnosis and evaluation of ß-TM in the future. Our study sheds new light on the pathogenesis of ß-TM.

[Pollution Characteristics and Sources of Wintertime Atmospheric Brown Carbon at a Background Site of the Yangtze River Delta Region in China].

To investigate the pollution characteristics and sources of atmospheric brown carbon (BrC) in Chongming Island, a background site of the Yangtze River Delta (YRD) region in China, PM2.5 samples collected from December 2018 to January 2019 were analyzed to determine their chemical compositions and optical properties. The results showed that the light absorption coefficient (Abs365,M) of BrC extracted by methanol at 365 nm was (5.39±3.33) M-1·m-1, which was 1.3 times of the water extracted BrC. Both increased significantly with the increase of pH values, suggesting that less acidic conditions can enhance the light absorption ability of BrC. In winter, both Abs365 and MAE365 (mass absorption efficiency) were higher in the nighttime than in the daytime. A strong linear correlation observed between Abs365 and levoglucosan (R2=0.72) indicated that many light absorbing substances in Chongming Island were derived from biomass burning emissions. During the campaign, nitro-aromatic compounds (NACs) and PAHs accounted for (1.5±1.1) ng·m-3 and (8.3±4.7) ng·m-3, respectively, contributing to 0.1% and 0.067% of the absorption of the total BrC at 365 nm, respectively. Positive matrix factorization (PMF) analysis further showed that biomass and fossil fuel combustions were the main sources of BrC in Chongming Island in winter, accounting for 56% of the total BrC, followed by secondary formation, accounting for 24% of the total BrC, with road dust contributing only 6%.

Rapid Identification and Subtyping of Enterobacter cloacae Clinical Isolates Using Peptide Mass Fingerprinting.

OBJECTIVE: To establish a domestic database of Enterobacteria cloacae (E. cloacae), and improve the identification efficiency using peptide mass fingerprinting. METHODS: Peptide mass fingerprinting was used for the identification and subtyping of E. cloacae. Eighty-seven strains, identified based on hsp60 genotyping, were used to construct and evaluate a new reference database. RESULTS: Compared with the original reference database, the identification efficiency and accuracy of the new reference database was greatly improved at the species level. The first super reference database for E. cloacae identification was also constructed and evaluated. Based on the super reference database and the main spectra projection dendrogram, E. cloacae strains were divided into two clades. CONCLUSION: Peptide mass fingerprinting is a powerful method to identify and subtype E. cloacae, and the use of this method will allow us to obtain more information to understand the heterogeneous organism E. cloacae.

Triptolide induces apoptosis and inhibits the growth and angiogenesis of human pancreatic cancer cells by downregulating COX-2 and VEGF.

Triptolide (TPL) inhibits the growth and proliferation of a wide range of human cancer cells, but the underlying mechanism is largely unknown. Here, we report that TPL induces apoptosis and inhibits proliferation of PANC-1 pancreatic cancer cells by downregulating cyclooxygenase-2 (COX-2) and vascular endothelial growth factor (VEGF). Cell viability and apoptosis were measured by MTT assay and flow cytometry. Real-time PCR and Western blot were used to examine the expression of COX-2 and VEGF. The Matrigel angiogenesis and Transwell migration were employed to assess tube formation and cell migration. Pancreatic cancer mouse xenografts were established to investigate the in vivo antitumor effects of TPL. TUNEL staining and immunohistochemistry were used to detect the apoptosis rate and protein expression in tumor tissues. TPL inhibited the proliferation of pancreatic cancer cells in a time and concentration-dependent manner and decreased the expression of COX-2 and VEGF in vitro. Furthermore, medium from TPL-treated PANC-1 cells inhibited the proliferation, migration, and tube formation of HUVECs. TPL significantly reduced the growth of pancreatic cancer mouse xenografts, accompanied by an induction of apoptosis, inhibition of angiogenesis, and reduction of COX-2 and VEGF. Our data indicate that suppressing the expression of COX-2 and VEGF may be one of the molecular mechanisms by which TPL induces apoptosis and inhibits the growth and angiogenesis of human pancreatic cancer cells.

[Detection of Cryptosporidium parvum in human stool using TaqMan real-time polymerase chain reaction].

The special DnaJ-like protein gene of Cryptosporidium parvum was amplified through designing special primers and TaqMan probes within the conserved and specific regions for this gene. method of real-time PCR assay for the detection of C. parvum was established. The specificity and sensitivity of PCR were also analyzed. By adding standard culture fluid in blank fecal sample, the sensitivity of the method was evaluated. The results showed that the detection limit of pure culture with real-time PCR assay was 26 oocysts/ml. The detection limit for C. parvum in artificially contaminated fecal sample was 2 600 oocysts/ml. The specificity of the method was verified with no amplification on DNA from other enteric parasites and bacteria. These results indicated that the real-time PCR method for C. parvum detection in fecal sample is simple, rapid, with high specificity and sensitivity.

[Effect of comprehensive control of schistosomiasis in Yangxin County, Hubei Province].

Since 2005, the project of comprehensive control of schistosomiasis has been implemented in Yangxin County. In 2010, the infection rates of residents and domestic animals were both below 2%, comparing to 2004, the rates decreased by 92.42% and 92.91%, respectively, and the area of susceptible zone and the infection rate of Oncomelania snails decreased by 86.25% and 84.93%, respectively. The county achieved the objective of endemic control in 2008.

[Questionnaire survey on replacing bovine with machine in Yangxin County].

A total of 405 households keeping cattle were surveyed by questionnaire in Yangxin County in 2008, the results showed that 215 of them (53.09%) were willing to replace cattle, 288 of them (71.11%) preferred to economic compensation, and 117 of them asked for compensation with machine.

A meta-analysis of the effects of energy intake on risk of digestive cancers.

AIM: To quantitatively assess the relationship between energy intake and the incidence of digestive cancers in a meta-analysis of cohort studies. METHODS: We searched MEDLINE, EMBASE, Science Citation Index Expanded, and the bibliographies of retrieved articles. Studies were included if they reported relative risks (RRs) and corresponding 95% CIs of digestive cancers with respect to total energy intake. When RRs were not available in the published article, they were computed from the exposure distributions. Data were extracted independently by two investigators and discrepancies were resolved by discussion with a third investigator. We performed fixed-effects meta-analyses and meta-regressions to compute the summary RR for highest versus lowest category of energy intake and for per unit energy intake and digestive cancer incidence by giving each study-specific RR a weight that was proportional to its precision. RESULTS: Nineteen studies consisting of 13 independent cohorts met the inclusion criteria. The studies included 995,577 participants and 5620 incident cases of digestive cancer with an average follow-up of 11.1 years. A significant inverse association was observed between energy intake and the incidence of digestive cancers. The RR of digestive cancers for the highest compared to the lowest caloric intake category was 0.90 (95% CI 0.81-0.98, P < 0.05). The RR for an increment of 239 kcal/d energy intake was 0.97 (95% CI 0.95-0.99, P < 0.05) in the fixed model. In subgroup analyses, we noted that energy intake was associated with a reduced risk of colorectal cancer (RR 0.90, 95% CI 0.81-0.99, P < 0.05) and an increased risk of gastric cancer (RR 1.19, 95% CI 1.08-1.31, P < 0.01). There appeared to be no association with esophageal (RR 0.96, 95% CI 0.86-1.07, P > 0.05) or pancreatic (RR 0.79, 95% CI 0.49-1.09, P > 0.05) cancer. Associations were also similar in studies from North America and Europe. The RR was 1.02 (95% CI 0.79-1.25, P > 0.05) when considering the six studies conducted in North America and 0.87 (95% CI 0.77-0.98, P < 0.05) for the five studies from Europe. CONCLUSION: Our findings suggest that high energy intake may reduce the total digestive cancer incidence and has a preventive effect on colorectal cancer.

The fibrils of Ure2p homologs from Saccharomyces cerevisiae and Saccharoymyces paradoxus have similar cross-ß structure in both dried and hydrated forms.

The ability to convert into amyloid fibrils is a common feature of prion proteins. However, not all amyloid-forming proteins act as prions. Here, we compared two homologs of the yeast prion protein Ure2 from Saccharomyces cerevisiae and Saccharomyces paradoxus, ScUre2p and SpUre2p, which have different prion propensities in vivo. We also addressed the controversial issue of whether hydrated fibrils of Ure2 show a fundamentally different X-ray diffraction pattern than dried samples. Using Fourier transform infrared spectrometry (FTIR) and wide angle X-ray scattering of dried and concentrated hydrated fibrils, we compared the fibril structure of ScUre2p and SpUre2p. The results show that fibrils of ScUre2p and SpUre2 have a similar cross-ß core under dried and hydrated conditions, with the same inter-strand and inter-sheet spacings. Given the different prion propensity of the two Ure2p homologs, this suggests that the detailed organization of the cross-ß core may play an important role in the efficiency of prion propagation.

Relationship between prion propensity and the rates of individual molecular steps of fibril assembly.

Peptides and proteins possess an inherent propensity to self-assemble into generic fibrillar nanostructures known as amyloid fibrils, some of which are involved in medical conditions such as Alzheimer disease. In certain cases, such structures can self-propagate in living systems as prions and transmit characteristic traits to the host organism. The mechanisms that allow certain amyloid species but not others to function as prions are not fully understood. Much progress in understanding the prion phenomenon has been achieved through the study of prions in yeast as this system has proved to be experimentally highly tractable; but quantitative understanding of the biophysics and kinetics of the assembly process has remained challenging. Here, we explore the assembly of two closely related homologues of the Ure2p protein from Saccharomyces cerevisiae and Saccharomyces paradoxus, and by using a combination of kinetic theory with solution and biosensor assays, we are able to compare the rates of the individual microscopic steps of prion fibril assembly. We find that for these proteins the fragmentation rate is encoded in the structure of the seed fibrils, whereas the elongation rate is principally determined by the nature of the soluble precursor protein. Our results further reveal that fibrils that elongate faster but fracture less frequently can lose their ability to propagate as prions. These findings illuminate the connections between the in vitro aggregation of proteins and the in vivo proliferation of prions, and provide a framework for the quantitative understanding of the parameters governing the behavior of amyloid fibrils in normal and aberrant biological pathways.

Deletion of a Ure2 C-terminal prion-inhibiting region promotes the rate of fibril seed formation and alters interaction with Hsp40.

Prions are proteins that can undergo a heritable conformational change to an aggregated amyloid-like state, which is then transmitted to other similar molecules. Ure2, the nitrogen metabolism regulation factor of Saccharomyces cerevisiae, shows prion properties in vivo and forms amyloid fibrils in vitro. Ure2 consists of an N-terminal prion-inducing domain and a C-terminal functional domain. Previous studies have shown that mutations affecting the prion properties of Ure2 are not restricted to the N-terminal prion domain: the deletion of residues 151-158 in the C-domain increases the in vivo prion-inducing propensity of Ure2. Here, we characterized this mutant in vitro and found that the 151-158 deletion has minimal effect on the thermodynamic stability or folding properties of the protein. However, deletion of residues 151-158 accelerates the nucleation, growth and fragmentation of amyloid-like aggregates in vitro, and the aggregates formed are able to seed formation of fibrils of the wild-type protein. In addition, the absence of 151-158 was found to disrupt the inhibitory effect of the Hsp40 chaperone Ydj1 on Ure2 fibril formation. These results suggest that the enhanced in vivo prion-inducing ability of the 151-158 deletion mutant is due to its enhanced ability to generate prion seeds.

Hypoxia stabilizes microtubule networks and decreases tumor cell chemosensitivity to anticancer drugs through Egr-1.

The hypoxic environment of solid tumor causes the tumor cells survive and which could protect them from death by facilitating resistance to therapy. Here, we provide evidence that hypoxia can increase tumor cell viability and proliferation through an Egr-1-dependant pathway. Hypoxia protected the microtubules from disassembly, and Egr-1 was colocalized with microtubules in different cell cycle stages. Knockdown of Egr-1 with its siRNA overcame the protection effect of hypoxia and increased the sensitivity of tumor cells to vinblastine under hypoxic conditions. Our results suggest a novel approach for increasing the sensitivity of tumor cells to chemotherapeutics that target microtubule assembly.

In vitro analysis of SpUre2p, a prion-related protein, exemplifies the relationship between amyloid and prion.

The yeast Saccharomyces cerevisiae contains in its proteome at least three prion proteins. These proteins (Ure2p, Sup35p, and Rnq1p) share a set of remarkable properties. In vivo, they form aggregates that self-perpetuate their aggregation. This aggregation is controlled by Hsp104, which plays a major role in the growth and severing of these prions. In vitro, these prion proteins form amyloid fibrils spontaneously. The introduction of such fibrils made from Ure2p or Sup35p into yeast cells leads to the prion phenotypes [URE3] and [PSI], respectively. Previous studies on evolutionary biology of yeast prions have clearly established that [URE3] is not well conserved in the hemiascomycetous yeasts and particularly in S. paradoxus. Here we demonstrated that the S. paradoxus Ure2p is able to form infectious amyloid. These fibrils are more resistant than S. cerevisiae Ure2p fibrils to shear force. The observation, in vivo, of a distinct aggregation pattern for GFP fusions confirms the higher propensity of SpUre2p to form fibrillar structures. Our in vitro and in vivo analysis of aggregation propensity of the S. paradoxus Ure2p provides an explanation for its loss of infective properties and suggests that this protein belongs to the non-prion amyloid world.

[Cost-effectiveness analysis of emergency endoscopic variceal ligation plus octreotide in the treatment of acute esophageal variceal bleeding in cirrhotic patients].

OBJECTIVE: To compare and evaluate the cost and effectiveness of endoscopic variceal ligation (EVL) at emergency plus octreotide versus octreotide alone in the treatment of acute esophageal variceal bleeding in cirrhotic patients. METHODS: Seventy-eight patients with active variceal bleeding under emergency endoscope, were assigned to two groups receiving either combined therapy of EVL at emergency and octreotide ('EVL' group) or a continuous infusion of octreotide alone ('octreotide' group). Both efficacy and cost-effectiveness were observed. RESULTS: There were no significant differences between the two groups in patients' characteristics, supporting treatment or general treatment. In group EVL, there appeared a significantly higher rate in controlling bleeding and lower complication rate than that of octreotide group(94.4% vs.78.6%, P = 0.045 and 19.4% vs. 42.9%, P = 0.027, respectively). Early rebleeding and mortality rate were also lower in group EVL, but with no significant differences between them (2.9% vs. 7.7%, P = 0.358 and 5.6% vs. 14.3%, P = 0.205, respectively). The combined therapy had a significantly shorter time of hemostasis, less administration of octreoid, fewer units of blood transfusion and shorter hospital stay (P < 0.001). The median costs of the combined therapy and octreotide alone were RMB 9046.5 Yuan and 13 743.6 Yuan,respectively (P = 0.045). The cost-effective ratio of group EVL seemed superior to that of octreoid group. CONCLUSION: The therapeutic scheme of emergency EVL plus octreotide was a more cost-effective one for controlling acute esophageal variceal bleeding.

Polo-like kinase 1 regulates mitotic arrest after UV irradiation through dephosphorylation of p53 and inducing p53 degradation.

Ultraviolet (UV) irradiation can result in cell cycle arrest. The reactivation of Polo-like kinase 1 (Plk1) is necessary for cell cycle reentry. But the mechanism of how Plk1 regulates p53 in UV-induced mitotic arrest cells remained elusive. Here we find that UV treatment leads HEK293 cells to inverse changes of Plk1 and p53. Over-expression of Plk1 rescue UV-induced mitotic arrest cells by inhibiting p53 activation. Plk1 could also inhibit p53 phosphorylation at Ser15, thus facilitates its nuclear export and degradation. Further examination shows that Plk1, p53 and Cdc25C can form a large complex. Plk1 could bind to the sequence-specific DNA-binding domain of p53 and active Cdc25C by hyperphosphorylation. These results hypothesize that Plk1 and Cdc25C participate in recovery the mitotic arrest through binding to the different domain of p53. Cdc25C may first be actived by Plk1, and then its phosphatase activity makes p53 dephosphorylated at Ser15.