Source apportionment and ozone formation mechanism of VOCs considering photochemical loss in Guangzhou, China

Understanding the sources and impact of volatile organic compounds (VOCs) on ozone formation is challenging when the traditional method does not account for their photochemical loss. In this study, online monitoring of 56 VOCs was carried out in summer and autumn during high ozone pollution episodes. The photochemical age method was used to evaluate the atmospheric chemical loss of VOCs and to analyze the effects on characteristics, sources, and ozone formation of VOC components. The initial concentrations during daytime were 5.12 ppbv and 4.49 ppbv higher than the observed concentrations in the summer and autumn, respectively. The positive matrix factorization (PMF) model identified 5 major emission sources. However, the omission of the chemical loss of VOCs led to underestimating the contributions of sources associated with highly reactive VOC components, such as those produced by biogenic emissions and solvent usage. Conversely it resulted in overestimating the contributions from VOC components with lower chemical activity such as liquefied petroleum gas (LPG) usage, vehicle emissions, and gasoline evaporation. Furthermore, the estimation of ozone formation may be underestimated when the atmospheric photochemical loss is not taken into account. The ozone formation potential (OFP) method and propylene-equivalent concentration method both underestimated ozone formation by 53.24 ppbv and 47.25 ppbc, respectively, in the summer, and by 40.34 ppbv and 26.37 ppbc, respectively, in the autumn. The determination of the ozone formation regime based on VOC chemical loss was more acceptable. In the summer, the ozone formation regime changed from the VOC-limited regime to the VOC-NOx transition regime, while in the autumn, the ozone formation regime changed from the strong VOC-limited regime to the weak VOC-limited regime. To obtain more thorough and precise conclusions, further monitoring and analysis studies will be conducted in the near future on a wider variety of VOC species such as oxygenated VOCs (OVOCs).

[The efficacy of chemotherapy re-challenge in third-line setting for metastatic colorectal cancer patients: a real-world study]

Objective: To explore the efficacy of chemotherapy re-challenge in the third-line setting for patients with metastatic colorectal cancer (mCRC) in the real world. Methods: The clinicopathological data, treatment information, recent treatment efficacy, adverse events and survival data of mCRC patients who had disease progression after treatment with oxaliplatin-based and/or irinotecan-based chemotherapy and received third-line chemotherapy re-challenge from January 2013 to December 2020 at Tianjin Medical University Cancer Institute and Hospital were retrospectively collected. Survival curves were plotted with the Kaplan-Meier method, and the Cox proportional hazard model was used to analyze the prognostic factors. Results: A total of 95 mCRC patients were included. Among them, 32 patients (33.7%) received chemotherapy alone and 63 patients (66.3%) received chemotherapy combined with targeted drugs. Eighty-three patients were treated with dual-drug chemotherapy (87.4%), including oxaliplatin re-challenge in 35 patients and irinotecan re-challenge in 48 patients. The remaining 12 patients were treated with triplet chemotherapy regimens (12.6%). Among them, as 5 patients had sequential application of oxaliplatin and irinotecan in front-line treatments, their third-line therapy re-challenged both oxaliplatin and irinotecan; 7 patients only had oxaliplatin prescription before, and these patients re-challenged oxaliplatin in the third-line treatment. The overall response rate (ORR) and disease control rate (DCR) reached 8.6% (8/93) and 61.3% (57/93), respectively. The median progression free survival (mPFS) and median overall survival (mOS) were 4.9 months and 13.0 months, respectively. The most common adverse events were leukopenia (34.7%) and neutropenia (34.7%), followed by gastrointestinal adverse reactions such as nausea (32.6%) and vomiting (31.6%). Grade 3-4 adverse events were mostly hematological toxicity. Cox multivariate analysis showed that gender (HR=1.609, 95% CI: 1.016-2.548) and the PFS of front-line treatments (HR=0.598, 95% CI: 0.378-0.947) were independent prognostic factors. Conclusion: The results suggested that it is safe and effective for mCRC patients to choose third-line chemotherapy re-challenge, especially for patients with a PFS of more than one year in front-line treatments.

[Colorectal cancer cells induce the formation of cancer-associated fibroblasts by activating the ERK signaling pathway in fibroblasts]

OBJECTIVE

To investigate the mechanism by which conditioned medium of colorectal cancer cells promotes the formation of cancer-associated fibroblasts (CAFs).

METHODS

Normal human colorectal fibroblasts (CCD-18Co cells) in logarithmic growth phase were treated with the conditioned media of colorectal cancer HCT116 cells (HCT116-CM) or Caco-2 cells (Caco-2-CM) alone or in combination with 300 nmol/L ERK inhibitor SCH772984. The expression levels of CAFs-related molecular markers were detected in the treated cells with real-time quantitative PCR (RT- qPCR) and immunofluorescence assay, and the changes in cell proliferation, colony formation and migration were assessed with RTCA, colony formation and wound healing assays; Western blotting was performed to detect the activated signaling pathways in the fibroblasts and the changes in CAFs formation after blocking of the signaling pathway.

RESULTS

HCT116-CM and Caco-2-CM significantly upregulated mRNA expression levels of CAFs markers (including α-SMA, FAP, FN and TGF-β) in CCD-18Co cells, and strongly promoted fibroblast transformation into CAFs (P < 0.05). The two conditioned media also promoted the proliferation, colony formation and migration of CCD-18Co cells (P < 0.05) and significantly increased the levels of α-SMA protein and ERK phosphorylation in the cells (P < 0.05). The ERK inhibitor SCH772984 obviously inhibited the expression of α-SMA and the transformation of CCD-18Co cells into CAFs induced by the conditioned medium of colorectal cancer cells (P < 0.05).

CONCLUSION

Colorectal cancer cells may induce the formation of colorectal CAFs by activating the ERK pathway in the fibroblasts.

m6A-mediated upregulation of lncRNA-AC026356.1 promotes cancer stem cell maintenance in lung adenocarcinoma via activating Wnt signaling pathway

LncRNA plays a pivotal role in the stemness and drug resistance of lung cancer. Here, we found that lncRNA-AC026356.1 was upregulated in stem spheres and chemo-resistant lung cancer cells. Our fish assay also shows that AC026356.1 was predominantly located in the cytoplasm of lung cancer cells and does not have protein-coding potential. Silencing AC026356.1 significantly inhibited proliferation and migration but increased apoptosis in A549-cisplatin (DDP) cells. Additionally, IGF2BP2 and the lncRNA-AC026356.1 positively regulated the proliferation and stemness of stem-like lung cancer cells. Further mechanistic investigation revealed that METTL14/IGF2BP2-mediated m6A modification and stabilization of the AC026356.1 RNA. Functional analysis corroborated that AC026356.1 acted as a downstream target of METTL14/IGF2BP2 and AC026356.1 silencing could block the oncogenicity of lung cancer stem-like cells. AC026356.1 expression was correlated with immune cell infiltration and T cell exhaustion. Compared with paired adjacent normal tissues, lung cancer specimens exhibited consistently upregulated METTL14/IGF2BP2/AC026356.1. M6A-modified METTL14/IGF2BP2/AC026356.1 loop may serve as a potential therapeutic target and prognostic predictor for lung cancer therapy and diagnosis in the clinic.

DOX-loaded hydroxyapatite nanoclusters for colorectal cancer (CRC) chemotherapy: Evaluation based on the cancer cells and organoids

It is meaningful to find suitable in vitro models for preclinical toxicology and efficacy evaluation of nanodrugs and nanocarriers or drug screening and promoting clinical transformation of nanocarriers. The emergence and development of organoids technology provide a great possibility to achieve this goal. Herein, we constructed an in vitro 3D organoid model to study the inhibitory effect of nanocarriers on colorectal cancer. And designed hydroxyapatite nanoclusters (c-HAP) mediated by polydopamine (PDA) formed under alkaline conditions (pH 9.0), then used c-HAP to load DOX (c-HAP/DOX) as nanocarrier for improved chemotherapy. In vitro, drug release experiments show that c-HAP/DOX has suitable responsive to pH, can be triggered to the facile release of DOX in a slightly acidic environment (pH 6.0), and maintain specific stability in a neutral pH value (7.4) environment. c-HAP/DOX showed an excellent antitumor effect in the two-dimensional (2D) cell model and three-dimensional (3D) patient-derived colon cancer organoids (PDCCOs) model. In addition, c-HAP/DOX can release a sufficient amount of DOX to produce cytotoxicity in a slightly acidic environment, entering efficiently into the colorectal cancer cells caused endocytosis and induced apoptosis. Therefore, organoids can serve as an effective in vitro model to present the structure and function of colorectal cancer tissues and be used to evaluate the efficacy of nanocarriers for tumors.

Construction and verification of a novel circadian clock related long non-coding RNA model and prediction of treatment for survival prognosis in patients with hepatocellular carcinoma

Circadian clock genes are significant in the occurrence and development of HCC and long-non coding RNAs (lncRNAs) are closely related to HCC progression. In this study, we aimed to establish a prognostic risk model for HCC. Circadian clock-related lncRNAs expressed in HCC were extracted from The Cancer Genome Atlas. A nomogram was established to predict individual survival rate. Biological processes enriched for risk model transcripts were investigated by Gene Set Enrichment Analysis. Further, we evaluated the relationship between risk score and immune-checkpoint inhibitor-related gene expression level. The Genomics of Drug Sensitivity in Cancer (GDSC) database was used to assess the sensitivity of tumors in high- and low-risk score groups to different drugs. A total of 11 circadian clock-related lncRNAs were included in multi-Cox proportional hazards model analysis to establish a risk model. Univariate and multivariate Cox regression analysis showed that the risk model was an independent risk factor in HCC. The risk model was a significantly associated with the immune signature. Further GDSC analysis indicated that patients in each risk score group may be sensitive to different anti-cancer drugs. QRT-PCR analysis results showed that C012073.1, PRRT3-AS1, TMCC1-AS1, LINC01138, MKLN1-AS, KDM4A-AS1, AL031985.3, POLH-AS1, LINC01224, and AC099850.3 were more highly expressed in Huh-7 and HepG2, compared to LO2, while AC008549.1 were lower expressed. Our work established a prognostic model for HCC. Risk score analysis indicated that the model is significantly associated with modulation tumor immunity and could be used to guide more effective therapeutic strategies in the future.

[Research and development technology platform and research progress of universal influenza vaccine]

Vaccination is the most effective measure to prevent influenza. However, due to the existence of antigen drift and/or antigen shift of influenza virus, the vaccine strains often do not match the epidemic strains, so that the protection provided by influenza vaccine is still limited. With the rapid development of new vaccine technology, a kind of influenza vaccine with extensive protection or universal has attracted great attention. It can effectively induce humoral and cellular immunity against the conserved epitopes of influenza virus, provide good protection against various types/subtypes of influenza virus, and has a rapid production platform, which is the ideal goal for the development of a new generation of universal influenza vaccine. This article reviews the latest research progress of influenza universal vaccine.

[Surface modification of titanium implant with hBMP-2/hIGF-1 for promoting biocompatibility and osteogenesis]

OBJECTIVE

To prepare the human bone morphogenetic protein-2(hBMP-2)/human insulin-like growth factor-1(hIGF-1)coating titanium(Ti)and assess its performance as a dental implant material.

METHODS

hBMP-2 and hIGF-1 were coated to the smooth surface of a Ti plate, and its efficacy for promoting bone formation and bone integration was compared with a pristine Ti plate.The surface characteristics of the metal samples were evaluated using scanning electron microscope (SEM) and by contact angle measurement.MG63 cells were seeded on the surface of the Ti plates, and MTT assay and alizarin red staining was used to examine the cell proliferation and formation of calcified nodules, respectively.Alkaline phosphatase (ALP)secretion of the cells was examined with ELISA, and cellular expressions of osteocalcin and osteopontin were detected with Western blotting for assessing osteogenesis.

RESULTS

SEM examination showed that the surface of Ti with hBMP-2 and hIGF-1 coating presented with a radial pattern resembling snowflakes.The contact angles of non-coated Ti, hBMP-2-coated Ti, hIGF-1-coated, and hBMP-2/-hIGF-1-coated Ti samples were 83.2°, 54°, 56° and 54°, respectively.Compared with the non-coated Ti plate, the surface-modified Ti samples showed a significantly smaller contact angle (P=0.032, 0.029, and 0.028), indicating a good hydrophilicity of the samples.MTT assay showed that MG63 cells grew well on the surface of the coated Ti plates.The hBMP-2/IGF-1 coating significantly induced cellular secretion of ALP(P=0.021, 0.014)and obviously promoted osteogenesis of MG63 cells (P < 0.05).Western blotting results showed that hBMP-2/IGF-1 coating significantly enhanced the expressions of osteocalcin and osteopontin in the seeded cells (P < 0.05).

CONCLUSION

hBMP-2 and hIGF-1 coating of Ti material can promote osteogenesis of the cells seeded on its surface to improve the performance of such Ti material as dental implants.

Curcumin inhibits the growth of liver cancer by impairing myeloid-derived suppressor cells in murine tumor tissues

Curcumin, one of the active ingredients of Curcuma longa (Jianghuang), has been reported to exert multiple bioactivities, including pro-apoptotic and anti-inflammatory activities. In recent years, curcumin has been extensively studied, and it has been revealed that curcumin inhibits the growth of numerous types of cancer. However, to the best of our knowledge, the inhibitory effects of curcumin on the activation or expansion of myeloid-derived suppressor cells (MDSCs) in liver cancer and the underlying mechanism have not yet been determined. Therefore, the present study aimed to investigate the inhibitory effect of curcumin on MDSC activity and the associated anti-neoplastic mechanism in a HepG2 ×enograft mouse model. The effect of curcumin on the viability of Huh-7, MHCC-97H and HepG2 cells in vitro was analyzed using a Cell Counting Kit-8 assay. The effects of curcumin on tumor growth, numbers of MDSCs, expression levels of proteins involved in the toll-like receptor 4 (TLR4)/NF-κB signaling pathway, levels of related inflammatory factors and angiogenesis were determined in HepG2 ×enograft model mice, which were given different doses of curcumin via intragastrical administration. The results of the present study revealed that curcumin inhibited the viability of Huh-7, MHCC-97H and HepG2 cells and the growth of HepG2 ×enograft tumors in mice. Flow cytometric analysis indicated that curcumin reduced the number of MDSCs in mouse xenograft tumors. In addition, the results demonstrated that curcumin inhibited the TLR4/NF-κB signaling pathway and the expression of inflammatory factors, including IL-6, IL-1β, prostaglandin E2 and cyclooxygenase-2, in mouse xenograft tumors. Furthermore, curcumin suppressed the secretion of granulocyte-macrophage colony-stimulating factor (GM-CSF) and granulocyte-colony stimulating factor (G-CSF), which are essential factors for MDSCs modulation, in tumor tissues. Additionally, curcumin was revealed to inhibit angiogenesis, which was demonstrated by the downregulation of the expression levels of vascular endothelial growth factor, CD31 and α-smooth muscle actin in western blotting, immunohistochemistry and immunofluorescence experiments. In conclusion, the findings of the present study identified a novel mechanism via which curcumin may suppress the growth of liver cancer by reducing the numbers of MDSCs and subsequently disrupting the process of angiogenesis. These conclusions were supported by the observed inactivation of the TLR4/NF-κB signaling pathway-mediated inflammatory response and the downregulation of GM-CSF and G-CSF secretion in xenograft tissues.

Exploration of the Potential Mechanism of Calculus Bovis in Treatment of Primary Liver Cancer by Network Pharmacology

AIM AND OBJECTIVE

Calculus Bovis (CB) has been employed to treat diseases for a long time. It has been identified to play significant anti-inflammatory and anti-tumor roles. However, the mechanism of treating primary liver cancer (PLC) remains to be revealed. This study aims to clarify the molecules and mechanisms of CB in treating PLC.

MATERIALS AND METHODS

After oral bioavailability (OB) and drug-likeness (DL) screening, 15 small molecules were identified as the potential ingredients against PLC. Following this, related targets network constructions and pathways were applied to clarify the mechanism of CB in treating PLC. An in vitro experiment was carried out to identify the function of CB in treating PLC.

RESULTS

Eleven compounds of CB were identified that play an anti-PLC role, including oleanolic acid, ergosterol, ursolic acid, etc. The potential targets which were observed include IL6, MAPK-8, VEGFA, Caspase-3, etc. Further analysis showed that the mechanism of CB in the treatment of PLC involved apoptosis-related pathways and immune-related pathways.

CONCLUSION

In summary, the current study combines network pharmacology and in vitro experiments to reveal the mechanism of CB against PLC. We concluded that 11 ingredients of CB have an anti-PLC effect. Furthermore, CB plays a key role in treating PLC mainly by apoptosisrelated pathways and immune-related pathways. Our experiment verifies that CB promotes the apoptosis of SMMC-7721.

[Incidence of deeply infiltrating endometriosis among 240 cases of pelvic endometriosis and analysis of its clinical and pathological characteristics]

Objective: To evaluate the incidence of deeply infiltrating endometriosis (DIE) among patients of pelvic endometriosis confirmed by pathology and to make analysis of its clinical and pathological characteristics. Methods: From January 1, 2018 to December 31, 2018, clinical data of 240 cases of pelvic endometriosis diagnosed by laparoscopy and pathology hospitalized in Peking University First Hospital were analyzed retrospectively for the characteristics of symptoms, pelvic examination and anatomic distribution of endometriosis foci. Results: (1) Among 240 cases of pelvic endometriosis, 94 were diagnosed with DIE with an incidence of 39.2% (94/240); of them the diagnosis were made preoperatively in 44 cases (46.8%, 44/94). (2) Compared with those without DIE, patients with DIE had higher rates of secondary dysmenorrhea [53.2% (50/94) versus 38.4% (56/146), P=0.033], anal pain [43.6% (41/94) versus 28.1% (41/146), P=0.013], dyspareunea [39.4% (37/94) versus 18.5% (27/146), P=0.001] and frequent bowel movement [33.0% (31/94) versus 15.8%(23/146), P=0.002]. (3) Patients with DIE had higher rates of bad movement of uterus [21.3% (20/94) versus 6.8% (10/146), P=0.001], painful nodularity on uterosacral ligaments [26.6% (25/94) versus 6.2% (9/146), P<0.01], painful nodularity of posterior fornix [19.1% (18/94) versus 4.8% (7/146), P<0.01], blue nodule in vaginal wall [6.4% (6/94) versus 0 (0/146), P=0.003] by pelvic examination compared with those without DIE. (4) Ninety-four patients with DIE had a total of 162 nodules, of those 88 (54.3%, 88/162) located in uterosacral ligaments, 14 (8.6%, 14/162) in the rectum, 7 (4.3%, 7/162) in vaginal wall, 6 (3.7%, 6/162) in ureter, 4 in bladder (2.5%, 4/162), 2 (1.2%, 2/162) in Douglas pouch. Forty-three DIE patients (45.7%, 43/94) had more than one nodules. Patients with DIE had concomitant ovarian endometriosis in 69 cases (73.4%, 69/94), with a total of 103 endometrial cysts. (5) Patients with DIE had a higher rate of obliterated Douglas pouch [76.6% (72/94) versus 19.2% (28/146), P<0.01]. Conclusions: More than one third of patients with pelvic endometriosis have concomitant DIE with a lower rate of preoperative diagnosis. Pelvic pains, bad movement of uterus and painful nodulirity around cervix suggest the presence of DIE.

Geographical distribution of ozone seasonality over China

Up to now, a nation-wide scale study of surface ozone (O₃) concentrations in China was limited due to scarce observation. Thanks to the establishment of national air quality monitoring network in 2013, surface O₃ data from 1402 stations during 2014-2017 were collected to investigate O₃ seasonality. Our analysis reveals that the variations of monthly O₃ averaged from daily mean concentration during a year show different temporal profiles depending on latitude. A unimodal structure (UMS) is generally found for latitudes over 35°N, whereas a bimodal structure (BMS) is in most of the cases identified south of 35°N. The peak of UMS is found in the period of May to July, whereas the first and second peaks of BMS are found from April to June, and from July to October, respectively. In addition, the seasonality of O₃ presents a strong dependence on pseudo-equivalent potential temperature and monsoonal clouds. The onset and retreat of warm and wet air are correlated to the summer minimum in BMS cases and to the sharp decrease of UMS in July. As far as the relationships between O₃ and carbon monoxide are concerned, the effects of clean maritime air masses on the summer trough of O₃ are not significant for inland sites. Overall, summer monsoon bringing warm and moist air and subsequent clouds leads to the suppression of photochemical production, thereby contributing directly to the geographical distribution of O₃ seasonality.

Association between phosphodiesterase type 5 inhibitors use and risk of melanoma: a meta-analysis

This meta-analysis aimed to clarify the actual association between the phosphodiesterase type 5 inhibitors (PDE5-Is) use and the risk of melanoma in erectile dysfunction (ED) patients. A systematic literature search was conducted in online databases in October, 2016 to identify studies focusing on the association between PDE5-Is use and the risk of melanoma. Summarized multivariate adjusted risk ratios (RRs) and 95% confidence intervals (CIs) were calculated to assess the strength of associations. A total of six clinical trials containing more than one million participants were included. ED patients  using PDE5-Is shared a significant high risk of melanoma (RR=1.12, 95% CI=1.03-1.21, p=0.006). Positive associations were observed in all kinds of prescriptions: single prescription (RR=1.20, 95% CI=1.06-1.35, p=0.003), medium number of prescription (RR=1.15, 95% CI=1.01-1.30, p=0.03), and high number of prescription (RR=1.18, 95% CI=1.05-1.34, P=0.006). Additionally, PDE5-Is were also found to be significantly associated with increased risk of basal cell carcinoma (RR=1.14, 95% CI=1.09-1.19, p<0.00001). Our study indicates that PDE5-Is use could significantly increase the risk of melanoma and basal cell carcinoma. However, the risk of melanoma did not rise significantly with the increased number of prescriptions. Consequently, owing to the lack of information about other potential synergistic factors, it is difficult for us to make a solid conclusion that application of PDE5-Is is the direct cause of increased risk of melanoma. Their relationship needs to be validated by further evidences.

Systematic analyses for candidate genes of milk production traits in water buffalo (Bubalus Bubalis)

Water buffalo (Bubalus bubalis) is of great economic importance as a provider of milk and meat in many countries. However, the milk yield of buffalo is much lower than that of Holstein cows. Selection of candidate genes related to milk production traits can be applied to improve buffalo milk performance. A systematic review of studies of these candidate genes will be greatly beneficial for researchers to timely and efficiently understand the research development of molecular markers for buffalo milk production traits. Here, we identified and classified the candidate genes associated with buffalo milk production traits. A total of 517 candidate genes have been identified as being associated with milk performance in different buffalo breeds. Nineteen candidate genes containing 47 mutation sites have been identified using the candidate gene approach. In addition, 499 candidate genes have been identified in six genome-wide association studies (GWASes) including two studies performed with the bovine SNP chip and four studies with the buffalo SNP chip. Genes CTNND2 (catenin delta 2), APOB (apolipoprotein B), FHIT (fragile histidine triad) and ESRRG (estrogen related receptor gamma) were identified in at least two GWASes. These four genes, especially APOB, deserve further study to explore regulatory roles in buffalo milk production. With growth in the number of buffalo genomic studies, more candidate genes associated with buffalo milk production traits will be identified. Therefore, future studies, such as those investigating gene location and functional analyses, are necessary to facilitate the exploitation of genetic potential and the improvement of buffalo milk performance.

No high Tibetan Plateau until the Neogene

The Late Paleogene surface height and paleoenvironment for the core area of the Qinghai-Tibetan Plateau (QTP) remain critically unresolved. Here, we report the discovery of the youngest well-preserved fossil palm leaves from Tibet. They were recovered from the Late Paleogene (Chattian), ca. 25.5 ± 0.5 million years, paleolake sediments within the Lunpola Basin (32.033°N, 89.767°E), central QTP at a present elevation of 4655 m. The anatomy of palms renders them intrinsically susceptible to freezing, imposing upper bounds on their latitudinal and altitudinal distribution. Combined with model-determined paleoterrestrial lapse rates, this shows that a high plateau cannot have existed in the core of Tibet in the Paleogene. Instead, a deep paleovalley, whose floor was <2.3 km above mean sea level bounded by (>4 km) high mountain systems, formed a topographically highly varied landscape. This finding challenges prevailing views on tectonic processes, monsoon dynamics, and the evolution of Asian biodiversity.

Extracellular vesicles in mesenchymal stromal cells: A novel therapeutic strategy for stroke

A stroke is a focal cerebral insult that frequently causes severe neurological deficit and mortality. Recent studies have demonstrated that multipotent mesenchymal stromal cells (MSCs) hold great promise for neurovascular remodeling and neurological function recovery following a stroke. Rather than a direct replacement of parenchymal brain cells, the therapeutic mechanism of MSCs is suggested to be the secretion of soluble factors. Specifically, emerging data described MSCs as being able to release extracellular vesicles (EVs), which contain a variety of cargo including proteins, lipids, DNA and various RNA species. The released EVs can target neurocytes and vascular cells and modify the cell's functions by delivering the cargo, which are considered to mediate the neural restoration effects of MSCs. Therefore, EVs may be developed as a novel cell-free therapy for neurological disorders. In the present review, the current advances regarding the components, functions and therapeutic potential of EVs are summarized and the use of MSC-derived EVs as a promising approach in the treatment of stroke are highlighted.

Adiponectin inhibits oxidization-induced differentiation of T helper cells through inhibiting costimulatory CD40 and CD80

Adiponectin is a multifunctional adipokine that has several oligomeric forms in the blood stream, which broadly regulates innate and acquired immunity. Therefore, in this study, we aimed to observe the differentiation of T helper (Th) cells and expression of costimulatory signaling molecules affected by adiponectin. The mRNA and protein expression levels of adiponectin and its receptors in oxidized low density lipoprotein cholesterol-treated endothelial cells were assayed by real time PCR and immunofluorescence. The endothelial cells were then treated with adiponectin with or without adipoR1 or adipoR2 siRNA and co-cultured with T lymphocytes. The distribution of Th1, Th2 and Th17 subsets were assayed by flow cytometry. The effects of adiponectin on costimulatory signaling molecules HLA-DR, CD80, CD86 and CD 40 was also assayed by flow cytometry. The results showed that endothelial cells expressed adiponectin and its receptor adipoR1 and adipoR2, but not T-cadherin. Adiponectin suppressed Th1 and Th17 differentiation through adipoR1 receptor, contributed to the inhibition of CD80 and CD40, and inhibited differentiation of Th1 and Th17 by inhibiting antigen presenting action.

Prognostic significance of the T2 substage in patients with esophageal squamous cell carcinoma

The invasion of the muscularis propria is defined as T2 stage in esophageal squamous cell carcinoma. Evidence is lacking regarding whether the T2 substage based on anatomy may serve as a prognostic indicator. This study aims to confirm the prognostic value of the T2 substage. The clinicopathological characteristics of 120 patients who had pathologically verified T2 tumors between 2006 and 2011 at the Tianjin Medical University Cancer Institute and Hospital were retrospectively studied. Based on the invasion depth, tumors that had penetrated the circular muscle layer were defined as T2a, while T2b disease referred to those that had invaded the longitudinal muscle layer. Factors potentially related to survival were analyzed with univariate and multivariate analyses. The logistic regression model was used to examine the factors associated with lymph node metastasis. To verify the prognostic value of the T2 substage further, patients with T1b and T3 stage disease during the same period were selected for comparisons. The univariate and multivariate analyses demonstrated that the T2 substage and N stage were independent prognostic factors. The T2 substage was highly relevant to lymph node metastasis in the logistic regression model (P = 0.044). When T1b and T3 was considered, the survival of T2a patients was closer to that of T1b patients, while the survival of T2b patients was closer to that of T3 disease (P = 0.000). The T2 substage was an independent prognostic factor. Patients with T2a tumors displayed a favorable survival, while the prognosis of T2b patients was closer to that of T3 patients.

Association between single nucleotide polymorphisms in AKT1 and the risk of prostate cancer in the Chinese Han population

AKT1, also known as v-akt murine thymoma viral oncogene homolog 1, is involved in the regulation of cell-survival and anti-apoptotic activities, which may affect the pathogenesis of various cancers. However, the association between genetic variants of AKT1 and the risk of developing prostate cancer has not been investigated before. This study investigated the associations between three polymorphisms (rs1130214, rs3730358, and rs2494732) in AKT1 and the risk of development of prostate cancer in the Chinese Han population. Sequenom MassARRAY & iPLEX technology were used to genotype these polymorphisms in 493 Chinese Han patients with prostate cancer and 309 age-matched healthy individuals. Compared to the CC genotype of the rs3730358 polymorphism, the CT genotype of the same polymorphism was strongly associated with a decreased risk of prostate cancer (OR = 0.617, 95%CI = 0.390-0.976, P = 0.037). However, there was no significant difference between the allele frequency of the rs3730358 polymorphism and those of the other two polymorphisms (P > 0.05). Moreover, no significant difference was found in the haplotype analysis (P > 0.05). Our study found that the variant genotype CT of rs3730358 of AKT1 was associated with a decreased risk of prostate cancer, which suggested that this polymorphism could play an important role in the development of the disease.

Assessment of regional air quality resulting from emission control in the Pearl River Delta region, southern China

To evaluate the impact of emission control measures on the air quality in the Pearl River Delta (PRD) region of South China, statistic data including atmospheric observations, emissions and energy consumptions during 2006-2014 were analyzed, and a Weather Research and Forecasting - Community Multi-scale Air Quality (WRF-CMAQ) model was used for various scenario simulations. Although energy consumption doubled from 2004 to 2014 and vehicle number significantly increased from 2006 to 2014, ambient SO₂, NO₂ and PM₁₀ were reduced by 66%, 20% and 24%, respectively, mainly due to emissions control efforts. In contrast, O₃ increased by 19%. Model simulations of three emission control scenarios, including a baseline (a case in 2010), a CAP (a case in 2020 assuming control strength followed past control tendency) and a REF (a case in 2020 referring to the strict control measures based on recent policy/plans) were conducted to investigate the variations of air pollutants to the changes in NO_x, VOCs and NH₃ emissions. Although the area mean concentrations of NO_x, nitrate and PM_2.5 decreased under both NO_x CAP (reduced by 1.8%, 0.7% and 0.2%, respectively) and NO_x REF (reduced by 7.2%, 1.8% and 0.3%, respectively), a rising of PM_2.5 was found in certain areas as reducing NO_x emissions elevated the atmospheric oxidizability. Furthermore, scenarios with NH₃ emission reductions showed that nitrate was sensitive to NH₃ emissions, with decreasing percentages of 0-10.6% and 0-48% under CAP and REF, respectively. Controlling emissions of VOCs reduced PM_2.5 in the southwestern PRD where severe photochemical pollution frequently occurred. It was also found that O₃ formation in PRD was generally VOCs-limited while turned to be NO_x-limited in the afternoon (13:00-17:00), suggesting that cutting VOCs emissions would reduce the overall O₃ concentrations while mitigating NO_x emissions in the afternoon could reduce the peak O₃ levels.

The SUMO-specific protease SENP5 controls DNA damage response and promotes tumorigenesis in hepatocellular carcinoma

OBJECTIVE

SUMOylation plays critical roles in a variety of physiological and pathological processes including tumorigenesis. SUMOylation is a reversible process which is mediated by the SENP (Sentrin/SUMO-specific protease) family to remove SUMO from conjugated substrates. SENP5 has been reported to play critical roles in the control of several cancers including breast cancer, osteosarcoma and oral squamous cell carcinoma. In this study, we uncovered a role of SENP5 in promoting tumorigenesis process in hepatocellular carcinoma (HCC) via regulating DNA damage response.

MATERIALS AND METHODS

The mRNA and protein levels of SENP5 in 10 pairs of HCC samples were determined by Realtime PCR and Western blot, respectively. SiRNAs were used to silence the expression of SENP5 in HepG2 cells. Male BALB/c nude mice were used to determine the roles of SENP5 on tumorigenesis. In vivo SUMOylation assay was used to detect the SUMOylation of ATRIP. Immunoprecipitation (IP) was used to detect the interaction between SENP5 and ATRIP.

RESULTS

We found that SENP5 was over-expressed in HCC samples and required for HCC cells proliferation both in vitro and in vivo. SENP5-depleted HepG2 cells exhibited hypersensitivity to IR and etoposide treatment with defective checkpoint activation including decreased activation of ATR and phosphorylation of ATR targets. At the molecular level, we found that SENP5 interacted with ATRIP and promoted ATRIP deSUMOylation.

CONCLUSIONS

Overall, our data suggest that SENP5 is required for HCC cell growth and might be a promising drug target for HCC.

Shed Syndecan-1 is involved in chemotherapy resistance via the EGFR pathway in colorectal cancer

Background:

Syndecan-1 (Sdc-1) shedding induced by matrix metalloproteinase-7 (MMP-7) and additional proteases has an important role in cancer development. However, the impact of Sdc-1 shedding on chemotherapeutic resistance has not been reported.

Methods:

We examined Sdc-1 shedding in colorectal cancer by enzyme-linked immunosorbent assay (ELISA), Dot blot, reverse transcription-PCR (RT-PCR), immunohistochemistry and so on, its impact on chemotherapeutic sensitivity by collagen gel droplet embedded culture-drug sensitivity test (CD-DST) and MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide), and potential mechanisms of action by Dot blot, western blot and immunofluorescence.

Results:

Sdc-1 shedding was increased in colorectal cancer patients, Sdc-1 serum levels in postoperative patients were lower than in preoperative patients, but still higher than those observed in healthy adults. Patients with high preoperative Sdc-1 serum levels were less responsive to 5-Fluorouracil, Oxaliplatin, Irintecan, Cisplatin or Paclitaxel chemotherapy. Moreover, the disease-free survival of patients with high preoperative Sdc-1 serum levels was significantly poorer. The possible mechanism of chemotherapy resistance in colorectal cancer can be attributed to Sdc-1 shedding, which enhances EGFR phosphorylation and downstream signalling.

Conclusions:

Shed Sdc-1 is involved in chemotherapy resistance via the EGFR pathway in colorectal cancer, and Sdc-1 serum levels could be a new prognostic marker in colorectal cancer.

Enhancement of glutathione production by altering adenosine metabolism of Escherichia coli in a coupled ATP regeneration system with Saccharomyces cerevisiae

AIMS

Adenosine triphosphate (ATP) during the enzymatic production of glutathione is necessary. In this study, our aims were to investigate the reason for low glutathione production in Escherichia coli coupled with an ATP regeneration system and to develop a new strategy to improve the system.

METHODS AND RESULTS

Glutathione can be synthesized by enzymatic methods in the presence of ATP and three precursor amino acids (L-glutamic acid, L-cysteine and glycine). In this study, glutathione was produced from E. coli JM109 (pBV03) coupled with an ATP regeneration system, by using glycolytic pathway of Saccharomyces cerevisiae WSH2 as ATP regenerator from adenosine and glucose. In the coupled system, adenosine used for ATP regeneration by S. cerevisiae WSH2 was transformed into hypoxanthine irreversibly by E. coli JM109 (pBV03). As a consequence, S. cerevisiae WSH2 could not obtain enough adenosine for ATP regeneration in the glycolytic pathway in spite of consuming 400 mmol l(-1) glucose within 1 h. By adding adenosine deaminase inhibitor to block the metabolism from adenosine to hypoxanthine, glutathione production (8.92 mmol l(-1)) enhanced 2.74-fold in the coupled system.

CONCLUSIONS

This unusual phenomenon that adenosine was transformed into hypoxanthine irreversibly by E. coli JM109 (pBV03) revealed that less glutathione production in the coupled ATP regeneration system was because of the poor efficiency of ATP generation.

SIGNIFICANCE AND IMPACT OF THE STUDY

The results presented here provide a strategy to improve the efficiency of the coupled ATP regeneration system for enhancing glutathione production. The application potential can be microbial processes where ATP is needed.

[Construction of T-vectors for the direct, unidirectional cloning and analysis of PCR-amplified promoters]

The amplification and cloning of promoters are regularly employed procedures to study the mechanism of gene regulation. In the present study we developed a method to construct T-vectors used for the direct and unidirectional cloning and analysis of promoters. These so-called T-vectors pEGFP-T and pGL3-T were derived from their parent promoterless vectors pEGFP-1 and pGL3-basic, respectively. To construct the T-vectors, an AhdI recognition site within the Ampr gene in pGL3-basic was silent mutated using overlap extension PCR. Then, a specially designed AhdI cassette was cloned into the respective parent vectors. The procedures of the T-vector construction involved a strategy to minimize the background of nonrecombinant transformants and to eliminate reverse orientation of the PCR products into the T-vectors. The cloning efficiencies of the two T-vectors were both above 85% when tested with a PCR product amplified from a sequence that was pre-confirmed to be able to initiate transcription, and moreover, the constructs harbored the inserts in a desired orientation at a >90% rate. In transient transfection assays, we demonstrated these T-vectors are functional. Thus, the present study provides an easy method to construct a series of T-vectors used for promoter characterization.

Activation of prostate-specific antigen precursor (pro-PSA) by prostin, a novel human prostatic serine protease identified by degenerate PCR

A novel serine protease was found in human prostate by degenerate oligonucleotide PCR amplification and cloned. The zymogen form of this enzyme, named prostinogen, is composed of 240 amino acid residues with an amino-terminal propiece of 5 residues and a 235-residue mature enzyme. The transcript has a signal peptide of 15 amino acid residues. The mature enzyme has 41% sequence identity with prostate specific antigen (PSA). Prostinogen was expressed in Escherichia coli and refolded from inclusion bodies. The zymogen, with a molecular mass of 28 kDa, was readily activated by agarose-immobilized trypsin to generate prostin, a serine protease, which cleaves the chromogenic substrate (N-benzoyl-L-Ile-L-Glu-L-Gly-L-Arg-p-nitroaniline hydrochloride) (S-2222). Recombinant prostin readily activates the precursor of PSA (pro-PSA) by cleavage of the amino terminal Arg(7)-Ile(8) peptide bond. These results indicate that prostin may be a physiological activator of pro-PSA following its own proteolytic activation, as part of a cascade system involving a series of serine protease precursor proteins in the prostate.

[The regulation of apoptosis by Bcl-2, bcl-X(L), Bcl-2alpha and Bax in chronic liver disease]

OBJECTIVE

To analyse the expression of Fas and Fas ligand (FasL) in patients of chronic hepatitis, liver cirrhosis and hepatocellular carcinoma and to study the regulation of apotosis by Bax and Bcl-2 subfamilies.

METHODS

The subfamily of Bcl-2 in the liver tissue was studied by immunohistochemistry.

RESULTS

In 156 cases of chronic liver disease the expression levels of Fas and FasL in the chronic hepatitis group were significantly higher than that in hepatocellular carcinoma group(P < 0.01). The expression level of Bax subfamily in the chronic hepatitis group was significantly higher than that of Bcl-2 subfamily.

CONCLUSION

It is suggested that Bcl-2 family is involved in the regulation of apoptosis in the chronic liver diseases.

Characterization of hPRP4 kinase activation: potential role in signaling

Mitogen-activated protein kinases (MAPKs) and cyclin-dependent kinases (CDKs) are important proline-directed Ser/Thr kinases that play distinct roles in cell differentiation and proliferation. hPRP4 (pre-mRNA processing gene), a human homologue of S. pombe Prp4, is a recently isolated CDK-like kinase with homology to MAPKs. Little is known about the mRNA processing function of hPRP4 or about the signaling pathways with which it is associated. hPRP4 is expressed in a variety of human tissues with the highest expression in the brain, lung and liver. In this paper, we characterize the activation of hPRP4 in COS-7 cells and show that hPRP4 also possesses a transcription factor activation function. hPRP4 is activated by epidermal growth factor (EGF) or forskolin treatment, but not tetradecanoyl phorbol acetate (TPA) nor ultraviolet (UV) irradiation. Activated hPRP4 phosphorylates residue Thr-417 on Elk-1 resulting in Elk-1 activation. This site of Elk-1 phosphorylation is distinct from that of other MAPKs. Coexpression of hPRP4 with an Elk-1 reporter construct causes trans activation of the reporter. These findings suggest that hPRP4, a CDK-like kinase related to MAPKs, may play a distinct role in signal transduction in addition to its role in mRNA processing.

Mirrorless lasing from mesostructured waveguides patterned by soft lithography

Mesostructured silica waveguide arrays were fabricated with a combination of acidic sol-gel block copolymer templating chemistry and soft lithography. Waveguiding was enabled by the use of a low-refractive index (1.15) mesoporous silica thin film support. When the mesostructure was doped with the laser dye rhodamine 6G, amplified spontaneous emission was observed with a low pumping threshold of 10 kilowatts per square centimeter, attributed to the mesostructure's ability to prevent aggregation of the dye molecules even at relatively high loadings within the organized high-surface area mesochannels of the waveguides. These highly processible, self-assembling mesostructured host media and claddings may have potential for the fabrication of integrated optical circuits.

The effects of feline retroviruses on cytokine expression

To identify potential roles of cytokines in retroviral pathogenesis, we used reverse transcription-quantitative competitive polymerase chain reaction (RT-qcPCR) assays to characterize mRNA levels of 19 different lymphokines, chemokines, monokines and hematopoietic growth factors in three feline cell lines productively infected with subgroup A feline leukemia virus (FeLV-A) or various feline immunodeficiency virus (FIV) strains. Infection of a CD8+, CD5- large granular lymphocyte (LGL) cell line with FeLV-A activated expression of interleukin-7 (IL-7), induced modest (4-fold) increases in granulocyte/macrophage colony-stimulating factor (GM-CSF) and leukemia inhibitory factor (LIF) transcripts, and decreased transforming growth factor-beta (TGF-beta) mRNA (4-fold). The LGL cells were not susceptible to infection by FIV. Infection of MYA-1 cells, a CD4+ T-lymphoblastoid cell line, with FeLV-A activated expression of macrophage inflammatory protein-1alpha (MIP-1alpha), increased transcript levels of GM-CSF (8-fold), macrophage CSF (M-CSF) (16-fold) and stem cell factor (SCF) (250-fold), and decreased (4-fold) expression of IL-10 and tumor necrosis factor-alpha (TNF-alpha). Productive infection with four different FIV molecular clones caused progressive MYA-1 cell death; however, the mRNA expression profiles were unchanged except for 2- to 4-fold increases in M-CSF and 16- to 500-fold increases in SCF. Thus, FIV-induced MYA-1 cytopathicity was not associated with dysregulation of pro-apoptotic or survival factor transcript levels. Lastly, productive infection of PNI cells, a marrow-derived fibroendothelial cell line, with FeLV-A or any of three FIV strains induced 4-fold higher levels of IL-12p40 transcripts and variably higher levels (4- to 64-fold) of GM-CSF. Two viral strains, the FIV-14 molecular clone and the clinical isolate FIV-5122, caused syncytia formation and unique activation of IL-1beta and stromal cell-derived factor-1 (SDF-1) expression, suggesting a potential role for those factors in viral spread and/or cytopathicity. In addition, infection with FIV-5122, but not the other FIV strains or FeLV-A, induced significant increases in mRNA levels of the hematopoietic inhibitors TNF-alpha and MIP-1alpha, along with increased concentrations of soluble proteins in culture supernatants. Consistent with this, supernatant from FIV-5122 infected PNI cells suppressed hematopoietic progenitor growth in colony assays, compared to supportive activities in supernatants from other infected or uninfected PNI cell cultures. Together, these data demonstrate that feline retroviruses alter cytokine mRNA levels in general and strain-specific patterns. These changes may result in specific alterations in cell function and contribute to retroviral pathogenesis. Our observations provide a basis for directed studies of candidate factors within the hematopoietic, thymic and lymphoid microenvironments.

Lymphokines modulate the growth and survival of thymic tumor cells containing a novel feline leukemia virus/Notch2 variant

Tumorigenesis occurs through a multistep process initiated by genetic lesions and facilitated by endogenous and external growth/survival signals. In many malignancies, specific oncogenic mutations correlate with phenotypic characteristics, inferring lineage-specific pathogenic mechanisms. To characterize these relationships in a unique feline tumor, we studied primary cells and two-cell lines independently-derived from a thymic lymphoma that contained and actively expressed a novel feline leukemia virus (FeLV) recombinant with transduced host Notch2 sequences. All three tumor cell populations contained similar FeLV/Notch2 proviral variants and phenotypically resembled mature thymocytes. Multiple Notch2 transcripts were expressed in the cell lines, including species that correspond to viral genomes and spliced subgenomic viral mRNA. Tumor cell line FeLV/Notch2 virus was packaged into virions; however, the variant was not efficiently transmitted to feline cells in vitro. Primary tumor cells constitutively expressed mRNA for interleukin-4 (IL-4), IL-6 and the p40 subunit of IL-12. Lymphokine mRNA was not detected in established tumor cell lines nor was T-cell growth-promoting activity found in culture supernatants. Exogenous IL-4 enhanced primary tumor cell survival, but inhibited proliferation of the cell lines. Interleukin-4 abrogated hydrocortisone-induced apoptosis in all three populations and had divergent effects on cell line clonogenic colony formation. Exogenous IL-7 and, to a lesser degree, IL-6 also had variable positive effects on the growth and viability of the tumor cell populations. Collectively, these data suggest that thymocytes are susceptible to the transforming potential of dysregulated Notch2 and that thymopoietic factors could, through overlapping and distinct mechanisms, promote the survival and outgrowth of FeLV/Notch2-containing neoplastic cells.

Hierarchically ordered oxides

Porous silica, niobia, and titania with three-dimensional structures patterned over multiple length scales were prepared by combining micromolding, polystyrene sphere templating, and cooperative assembly of inorganic sol-gel species with amphiphilic triblock copolymers. The resulting materials show hierarchical ordering over several discrete and tunable length scales ranging from 10 nanometers to several micrometers. The respective ordered structures can be independently modified by choosing different mold patterns, latex spheres, and block copolymers. The examples presented demonstrate the compositional and structural diversities that are possible with this simple approach.

Angiotensin II stimulates activation of Fos-regulating kinase and c-Jun NH2-terminal kinase in neuronal cultures from rat brain

c-Fos/c-Jun dimers (activating protein-1 transcription factor) are involved in the modulatory actions of angiotensin II (Ang II) on brain norepinephrine neurons, effects mediated via Ang II type 1 (AT1) receptors. The transcriptional activities of c-Fos and c-Jun can be augmented by Fos-regulating kinase (FRK) and c-Jun NH2-terminal kinase (JNK), respectively. In this study, we investigated the effects of Ang II on FRK and JNK activities in neurons cultured from newborn rat hypothalamus and brain stem, which include a population of catecholaminergic cells containing AT1 receptors. Ang II caused time-dependent increases in the activation of FRK and JNK, effects completely inhibited by the AT1 receptor antagonist losartan but not by the Ang II type 2 (AT2) receptor blocker PD123,319. The stimulation of FRK activity by Ang II was abolished by the protein kinase C (PKC) inhibitor GF109203X or the calcium chelator BAPTA, but not by inhibition of calmodulin or calcium/calmodulin-dependent protein kinase II. However, the activation of JNK by Ang II was not dependent on PKC or another calcium-dependent mechanism. These data demonstrate that Ang II stimulates activation of FRK and JNK in neuronal cells, actions that may contribute to the neuromodulatory effects of this peptide.

Bacterial expression and purification of biologically active mouse c-Fos proteins by selective codon optimization

A simple strategy using selective codon optimization was devised to express mouse c-Fos protein in high levels in E. coli. Ten arginine codons located in the basic region were optimized to achieve high levels of protein expression. The c-Fos protein was purified to near homogeneity and was demonstrated to be biologically active by assaying its several biological activities.

Membrane binding and enzymatic activation of a Dbl homology domain require the neighboring pleckstrin homology domain

Dbl-homology (DH) domains are invariably located immediately N-terminal to a pleckstrin homology (PH) domain. To understand the functional relationship between these two domains we expressed the DH domain alone, the PH domain alone, and the DH-PH combination of the invasion inducing protein Tiam-1 fused to glutathione-S-transferase (GST) or green fluorescent protein (GFP). We found that the GST-DH-PH and the GST-PH constructs bind to preparations of brain membranes and to the beta gamma subunits of trimeric G proteins in vitro, while the GST-DH and GST control do not. The GFP-DH-PH and GFP-PH constructs are localized to peripheral membranes of COS-7 cells in vivo, while GFP and GFP-DH domain constructs are found diffusely in the cytoplasm. The DH-PH domain combination activates Jun N-terminal kinase (JNK) strongly, but the DH domain alone and the PH domain alone have little effect. We conclude that membrane localization and enzymatic activation of the DH domain require the adjacent PH domain.

c-Jun can recruit JNK to phosphorylate dimerization partners via specific docking interactions

Structurally related serine/threonine kinases recognize similar phosphoacceptor peptides in vitro yet in vivo, they phosphorylate distinct substrates. To understand the basis for this specificity, we studied the interaction between the Jun kinases (JNKs) and Jun proteins. JNKs phosphorylate c-Jun very efficiently, JunD less efficiently, but they do not phosphorylate JunB. Effective JNK substrates require a separate docking site and specificity-conferring residues flanking the phosphoacceptor. The docking site increases the efficiency and specificity of the phosphorylation reaction. JunB has a functional JNK docking site but lacks specificity-conferring residues. Insertion of such residues brings JunB under JNK control. JunD, by contrast, lacks a JNK docking site, but its phosphoacceptor peptide is identical to that of c-Jun. Substrates such as JunD can be phosphorylated by JNK through heterodimerization with docking competent partners. Therefore, heterodimerization can affect the recognition of transcription factors by signal-regulated protein kinases.

Adenovirus E1A downregulates cJun- and JunB-mediated transcription by targeting their coactivator p300

Transcription factors and cofactors play critical roles in cell growth and differentiation. Alterations of their activities either through genetic mutations or by viral oncoproteins often result in aberrant cell growth and tumorigenesis. The transcriptional cofactor p300 has recently been shown to be complexed with transcription factors YY1 and CREB. Adenovirus E1A oncoproteins target these transcription complexes via physical interactions with p300, resulting in alterations of transcription mediated by these transcription factors. Here we show that p300 is also critical for repression by E1A of the activities of cJun and JunB, two members of the AP-1 transcriptional complexes. This repressive effect of E1A is dependent on the p300-binding domain of E1A and can be relieved by overexpression of p300. These results suggest that p300 serves as a mediator protein for downregulation of AP-1 activity by E1A. This hypothesis was further supported by the following observations: (i) in the absence of E1A, overexpression of p300 stimulated transcription both through an AP-1 site present in the collagenase promoter and through Jun proteins in GAL4 fusion protein-based assays; and (ii) overexpression of a mutant p300 lacking the E1A-interacting domain reduced the responsiveness of Jun-dependent transcription to E1A repression. As predicted from the functional results, p300 physically interacted with the Jun proteins. These findings thus established that p300 is a cofactor for cJun and JunB. We propose that p300 is a common mediator protein through which E1A gains control over multiple transcriptional regulatory pathways in the host cells.

Antitumor promotion by phenolic antioxidants: inhibition of AP-1 activity through induction of Fra expression

Induction of phase 2 detoxification enzymes by phenolic antioxidants can account for prevention of tumor initiation but cannot explain why these compounds inhibit tumor promotion. Phase 2 genes are induced through an antioxidant response element (ARE). Although the ARE resembles an AP-1 binding site, we show that the major ARE binding and activating protein is not AP-1. Interestingly, AP-1 DNA binding activity was induced by the phenolic antioxidant tert-butylhydroquinone (BHQ), but the induction of AP-1 transcriptional activity by the tumor promoter 12-O-tetradecanoylphorbol 13-acetate (TPA) was inhibited by this compound. BHQ induced expression of c-jun, junB, fra-1, and fra-2, which encode AP-1 components, but was a poor inducer of c-fos and had no effect on fosB. Like c-Fos and FosB, the Fra proteins heterodimerize with Jun proteins to form stable AP-1 complexes. However, Fra-containing AP-1 complexes have low transactivation potential. Furthermore, Fra-1 repressed AP-1 activity induced by either TPA or expression of c-Jun and c-Fos. We therefore conclude that inhibitory AP-1 complexes composed of Jun-Fra heterodimers, induced by BHQ, antagonize the transcriptional effects of the tumor promoter TPA, which are mediated by Jun-Fos heterodimers. Since AP-1 is an important mediator of tumor promoter action, these findings may explain the anti-tumor-promoting activity of phenolic antioxidants.

[A study of the relationship between expression of IGF-II, IGF-IIR, HBxAg and the DNA ploidy, cell cycle of hepatocytes in hepatocarcinoma]

In order to study the role of insulin-like growth factor II (IGF-II) in the development of hepatocarcinoma (HCC), the expression of IGF-II, IGF-II receptor (IGF-IIR) and HBxAg in HCC was studied with immunohistochemistry (PAP method). Meanwhile DNA ploidy and S-phase fraction of hepatocytes were analyzed with flow cytometry. The results were as follows: (1) IGF-II, IGF-IIR and HBxAg showed positive staining simultaneously in the tumor tissues of 93% (n = 15) of the HCC cases with chronic liver disease and with positive evidence of HBV; (2) The mean S-phase incidence in tissues of IGF-II positive HCC was 28.6 +/- 6.4%; this was higher than 12.8 +/- 2.4% in the IGF-II negative tumors (P < 0.05); (3) The incidence of DNA-aneuploidy in IGF-II positive liver tissues was 100% (10/10); this was higher than 60% (6/10) in IGF-II negative liver tissues (P < 0.05). It is suggested that IGF-II might play an important role in the development of HCC when there is evidence of HBV and chronic liver disease involvement. IGF-II positive staining HCC have increased proliferative activity as compared with IGF-II negative staining tumors.