[Role of endocytosis in cell surface CXC chemokine receptor 4 expression of stem cells from apical papilla]

OBJECTIVE

To evaluate the change of cell surface CXC chemokine receptor 4 (CXCR4) expression of stem cells from apical papilla (SCAP) after the inhibition of endocytotic pathway, thus to provide experimental basis for the mechanism of SCAP migration.

METHODS

The immunofluorescence analysis was conducted to examine the co-expression of CXCR4 and endocytotic compartments, including early endosomes, recycling endosomes and lysosomes in SCAP. Several Rab proteins were applied as markers of organelles in the endocytotic pathway, including Rab5 for early endosomes, Rab11A for recycling endosomes, and Lamp1 for lysosomes. The co-localization of CXCR4 with these endodontic compartments was further observed by proximity ligation assay (PLA). SCAP was treated with two kinds of endocytotic inhibitors, Blebbistatin and Dynasore, at a concentration of 80 μmol/L, respectively. The conditioning time was 1 hour. Flow cytometry was carried out to evaluate the proportion of SCAP that expressed CXCR4 on cell surface. The data were analysed by analysis of variance (ANOVA).

RESULTS

The red staining of CXCR4 on immunofluorescence confocal microscopy predominantly overlapped with the green staining of Rab5 and Rab11A, and partly overlapped with Lamp1. It indicated that most CXCR4 molecules were located in early endosomes and recycling endosomes, and some were located in lysosomes. The PLA results revealed that the co-localizaiton of CXCR4 with endocytotic compartments could be observed in early endosomes, recycling endosomes and lysosomes. According to the results of flow cytometry, the proportion of SCAP that expressed CXCR4 on cell surface was as low as 0.13%±0.10%. After the inhibition of endocytosis by pretreating the cells with the following two inhibitors, Blebbistatin and Dynasore, the percentage of SCAP that positively expressed CXCR4 on cell surface was significantly increased to 13.34%±1.31% in Blebbistatin group and 4.03%±0.92% in Dynasore group (F=16.721, P<0.001). Moreover, the number of SCAP that expressed CXCR4 on cell surface in Blebbistatin group was significantly higher than that in Dynasore group (P<0.001).

CONCLUSION

The inhibition of endocytotic pathway could increase the number of SCAP that expressed CXCR4 on cell surface, and provide potency for the migration of SCAP.

Development and validation of the Stressful Experiences in Transit Questionnaire (SET-Q) and its Short Form (SET-SF)

Background: Previous studies have demonstrated that traumatic experiences from countries of origin (so-called pre-migratory factors), as well as stressors in countries of destination (so-called post-migratory factors), are related to the extent of mental health difficulties and psychological well-being of refugees. However, numerous risks that this population is exposed to during transit have so far been neglected. Objective: The aim of this research was to construct and validate a questionnaire for assessing stressful and traumatic experiences in transit as well as its short form, which would at the same time provide information on one's stressful experiences as well as existing risks that refugees are exposed to on their journey. Method: The study was realized in three phases - item construction, item revision and instrument validation. In the validation phase, a total of 226 refugees completed the Stressful Experiences in Transit Questionnaire (SET-Q), along with Harvard Trauma Questionnaire (HTQ) Parts I and IV, Hopkins Symptom Checklist-25 (HSCL-25) and Beck Depression Inventory - II (BDI-II). Results: Refugees were exposed to an average of 13 stressful events during transit. SET-Q total score was positively correlated with HTQ Part IV Post-Traumatic Stress Disorder (PTSD) and Self-Perception of Functioning scales (SPFS) while the number of stressful experiences with the local population was positively related to BDI-II depression symptoms. Moreover, SET-Q scores were significant predictors of PTSD and SPFS even after traumatic experiences in the country of origin, assessed by HTQ Part I, were taken into account. A short form of the questionnaire (SET-SF) has also been developed. Conclusions: SET-Q is a valid instrument for measuring the scope of stressful experiences refugees have been exposed to during transit, targeted for this population specifically. Furthermore, SET-SF has the potential to assess the same extent of stressful experiences with a significantly reduced number of items.

[Rasfonin inhibits proliferation and migration of osteosarcoma 143B cells]

OBJECTIVE

To investigate the effects of rasfonin, a fungal secondary metabolite, on the proliferation and migration of osteosarcoma 143B cells.

METHODS

3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium, inner salt (MTS) assay was performed to examine 143B cell viability following treatment of rasfonin. Using dimethyl sulfoxide (DMSO) group as control, cell viability was detected when 143B cells were treated with rasfonin (3 μmol/L and 6 μmol/L) for 12 or 24 hours. The effect of rasfonin on colony forming ability was detected by clone formation assay. 143B cells treated with DMSO or rasfonin (3 μmol/L) for one week, and the number of clones formed in the two groups was counted. Wound healing and transwell assay were employed to analyze cell invasion and migration upon rasfonin challenge. The DMSO group was used as control while rasfonin (3 μmol/L) was used for 24 hours. The wound healing rate and the number of invasive cells were compared between the two groups. The intracellular autophagosomes were monitored by transmission electron microscopy when 143B cells were treated with DMSO or rasfonin (3 μmol/L) for 4 hours. The expression of p62, microtubule-associated protein 1 light chain 3 fusion protein (LC3) and poly (ADP-ribose) polymerase-1 (PARP-1) in response to rasfonin were detected by immunoblotting assay.

RESULTS

Rasfonin reduced the viability of 143B cells in a dose-dependent manner (12 h: F=31.36, P<0.01; 24 h: F=67.07, P<0.01). Rasfonin (3 μmol/L) completely inhibited the clonal formation of 143B cells (P<0.01). The wound healing result revealed that rasfonin significantly decreased migratory ability of 143B cells (33.91%±0.83% vs. 65.11%±0.94%, P<0.01), whereas its treatment significantly reduced the number of 143B cells penetrating through Matrigel-containing basement membrane (21.33±1.45 vs. 49.33±2.40, P<0.01). Compared with the control group, rasfonin markedly increased the number of autophagic vacuoles. The immunoblotting results revealed that rasfonin increased LC3-II accumulation and decreased p62 levels. Choloroquine (CQ), an often used autophagic inhibitor, further accumulated rasfonin-induced LC3-II. In addition, rasfonin appeared to cause the cleavage of PARP-1.

CONCLUSION

Rasfonin induced autophagy and activated caspase-dependent apoptosis in 143B cells concurring with suppressing the proliferation and migration of the cells; these results provide an experimental basis for rasfonin as a potential therapeutic agent for osteosarcoma.

Impacts of tropical forest disturbance on species vital rates

Tropical forests are experiencing enormous threats from deforestation and habitat degradation. Much knowledge of the impacts of these land-use changes on tropical species comes from studies examining patterns of richness and abundance. Demographic vital rates (survival, reproduction, and movement) can also be affected by land-use change in a way that increases species vulnerability to extirpation, but in many cases these impacts may not be manifested in short-term changes in abundance or species richness. We conducted a literature review to assess current knowledge and research effort concerning how land-use change affects species vital rates in tropical forest vertebrates. We found a general paucity of empirical research on demography across taxa and regions, with some biases toward mammals and birds and land-use transitions, including fragmentation and agriculture. There is also considerable between-species variation in demographic responses to land-use change, which could reflect trait-based differences in species sensitivity, complex context dependencies (e.g., between-region variation), or inconsistency in methods used in studies. Efforts to improve understanding of anthropogenic impacts on species demography are underway, but there is a need for increased research effort to fill knowledge gaps in understudied tropical regions and taxa. The lack of information on demographic impacts of anthropogenic disturbance makes it difficult to draw definite conclusions about the magnitude of threats to tropical ecosystems under anthropogenic pressures. Thus, determining conservation priorities and improving conservation effectiveness remains a challenge.

[Role of allograft inflammatory factor-1 in regulating the proliferation, migration and apoptosis of colorectal cancer cells]

OBJECTIVE

To investigate the role of allograft inflammatory factor-1 (AIF-1) in colorectal cancer (CRC) progression and explore the possible mechanism.

METHODS

The expression levels of AIF-1 in 70 CRC tissues and paired adjacent tissues were detected using immunohistochemistry and Western blotting, and the correlation of AIF-1 expression with the clinicopathological features of the patients was analyzed. In the CRC cell line SW480, the functional role of AIF-1 in regulating tumor progression was investigated by transfecting the cells with an AIF-1-overexpressing plasmid (AIF-1) and a negative control plasmid (NC). EdU proliferation assay and flow cytometry were used to assess the cell proliferation and cell cycle changes; Transwell migration assay and Annexin V-APC/7-AAD apoptosis assay kit were used to analyze the cell migration and apoptosis. The changes in the biological behaviors of the cells were observed after application of SB203580 to block the p38 MAPK pathway. The expression levels of CDK4, cyclin D1, P21, P27, MMP2, MMP9, Bax, Bcl2, Bcl-xl, p38 and p-p38 were detected using Western blotting.

RESULTS

AIF-1 was down-regulated in CRC tissues compared with the adjacent normal tissues, and its expression level was positively correlated with lymph node metastasis (P=0.008), TNM stage (P=0.003) and tumor size (P=0.023). Overexpression of AIF-1 in SW480 cells significantly reduced EdU-positive cells and caused obvious cell cycle arrest in G1 phase (P<0.05). AIF-1 overexpression resulted in significantly lowered protein expressions of CDK4 and cyclin D1, enhanced expressions of P21 and P27, attenuated cell migration ability (P<0.001), and decreased protein levels of MMP2 and MMP9. AIF-1 overexpression also induced obvious apoptosis of SW480 cells (P<0.01), significantly increased the protein levels of Bax and p-p38, and decreased the protein levels of Bcl-2 and Bcl-xl; SB203580 significantly attenuated the apoptosis-inducing effect of AIF-1 overexpression.

CONCLUSION

AIF-1 plays the role of a tumor suppressor in CRC by inhibiting cell proliferation, suppressing cell migration and inducing cell apoptosis. AIF-1 overexpression promotes the apoptosis of CRC cells by activating the p38 MAPK pathway.

[Twist regulates proliferation, migration and invasion of osteosarcoma cells in vitro]

OBJECTIVE

To investigate the role of Twist in regulating the proliferation, migration, and invasion of osteosarcoma cells with different levels of malignancy.

METHODS

The baseline expressions of Twist in 3 different osteosarcoma cell lines (143B, MG63 and TE85) were detected using real-time PCR and Western blotting. The cells were infected with the recombinant adenoviruses Ad-Twist or Ad-siTwist for Twist overexpression or knockdown, respectively, and the cell growth curves were drawn to assess the cell proliferation. The migration abilities and invasiveness of the cells were evaluated using wound healing assay and Transwell assay. Luc-labeled 143B cells infected with Ad-Twist or Ad-siTwist were intrathecally injected to establish nude mouse models bearing osteosarcoma xenografts, in which the tumor formation was monitored using living body imaging technique.

RESULTS

The baseline expressions of Twist in the 3 osteosarcoma cells were significantly higher than that in C3H10 cells (P<0.05). Twist expression was the highest in 143B cells followed by MG63 cells, and was the lowest in TE85 cells, indicating its positive correlation with the level of malignancy of the osteosarcoma cells. Ad-Twist or Ad-siTwist infection efficiently enhanced or lowered Twist expressions at both mRNA and protein levels in osteosarcoma cells (P<0.05). Twist overexpression resulted in enhanced proliferation, migration and invasion abilities of osteosarcoma cells, and Twist knockdown obviously inhibited the cell proliferation, migration and invasion. In nude mice, 143B cells with Twist overexpression showed accelerated tumor formation compared with the control cells, while Twist knockdown significantly inhibited the tumor formation ability of the cells.

CONCLUSION

Twist overexpression can promote the proliferation, migration, invasion and tumorigenicity of osteosarcoma cells.

[Effect of outer membrane vesicles derived from Escherichia coli on proliferation, apoptosis and migration of human neuroblastoma SK-N-SH cells in vitro]

OBJECTIVE

To investigate the effect of outer membrane vesicles derived from Escherichia coli on proliferation, apoptosis and migration of human neuroblastoma SK-N-SH cells in vitro.

METHODS

The outer membrane vesicles (OMVs) were obtained from wild-type Escherichia coli with ultracentrifugation method, and the morphology of the OMVs was observed by transmission electron microscopy and the vesicle diameter was determined using MALVERN ZEN3690. Human neuroblastoma SK-N-SH cells were treated with the OMVs at low (100 µg/mL), moderate (500 µg/mL) and high (1000 µg/mL) doses, and 24, 48 and 72 h later, the cell proliferation activity was detected with MTT assay. The expressions of apoptosis-related marker caspase-3 was detected using Western blotting, and TUNEL assay was performed to detect the cell apoptosis. The migration capacity of SK-N-SH cells was evaluated using Transwell migration assay.

RESULTS

The isolated OMVs showed a circular or elliptical hollow structure with double-layer membrane and a diameter range of 30-450 nm. Compared with the control cells, SK-N-SH cells treated with the OMVs showed significantly lowered cell proliferation capacity with enhanced expression of caspase-3. Treatment of the cells with the OMVs resulted in increased cell apoptosis and significantly lowered migration capacity (P<0.05).

CONCLUSION

The OMVs derived from Escherichia coli can produce cytotoxicity against SK-N-SH cells and might serve as a therapeutic agent for refractory neuroblastoma.

[MiR-218 Inhibits Migration and Invasion of Lung Cancer Cell by Regulating Robo1 Expression]

BACKGROUND

To explore the function and the potential molecular mechanism of miR-218 in lung cancer cell.

METHODS

The expression of miR-218 mRNA was determined by real-time PCR in lung cancer tissues, adjacent tissues and lung cancer cells. Transwell assay was used to detect the migration and invasion of A549 cell after transfected with Anti-miR-218 or negative control and HC4006 cell after transfected with miR-218 mimics and miR-218 negative control. Targetscan and MiRanda were used to calculate the potential targets of miR-218 and Luciferase reporter assay was performed to identify that the Robo1 was one target genes of miR-218. Transwell assay was used to detect whether miR-218 regulated the invasion of lung cancer cell transfected with anti-miR-218 or negative control via Robo1.

RESULTS

The expression of miR-218 in the lung cancer tissues was significantly lower than that in the adjacent tissues (P<0.05). Inhibition of miR-218 improved the migration and invasion of A549 cell. Overexpression of miR-218 suppressed the migration and invasion of HCC4006 cell. The co-transfection of anti-miR-218 or miR-218 mimics and the Robo1 3'UTR increased or reduced the luciferase activity of Robo1 compared with the control group (P<0.05). Inhibition of miR-218 and Robo1 recovered the invaded cells of A549. Overexpression of miR-218 and inhibition of Robo1 reduced the number of the invased cells of HCC4006. These results suggested that miR-218 banded Robo1 directly and inhibited lung cancer cell invasion by targeting Robo1.

CONCLUSIONS

MiR-218 inhibited the migration and invasion of lung cancer cells through regulating Robo1 expression.
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[Methyltransferase inhibitor BIX01294 promotes the migration and inhibits decidualization of mouse uterine stromal cells in vitro]

OBJECTIVE

To investigate the effect of BIX01294 (BIX), a methyltransferase inhibitor, on the migration and decidualization of the stromal cells in mouse uterus.

METHODS

Mouse endometrial stromal cells were isolated and cultured from the uterus of pregnant mice on day 3.5 of gestation. The migration and decidualization of mouse endometrial stromal cells treated with BIX at different concentrations were observed with wound healing assay and real-time PCR.

RESULTS

The migration distance of mouse endometrial stromal cells increased as the BIX concentration increased within the range below 15 µmol/L. Compared with the control cells, the cells treated with BIX (15 µmol/L) showed significantly increased migration distances, but increasing BIX concentration to 20 µmol/L did not further increase the cell migration distance and began to cause cell death. Compared with the control cells, the BIX-treated stromal cells exhibited significantly down-regulated expression of Ehmt2 mRNA, and 15 µmol/L BIX caused inhibition of decidualization in the stromal cells.

CONCLUSION

Within a defined concentration range, BIX promotes the migration and inhibits decidualization of mouse uterine stromal cells by inhibiting the expression of Ehmt2 mRNA.

[Inhibitory effect of KyoT2 overexpression on proliferation and migration of airway smooth muscle cells in mice with asthma]

OBJECTIVE

To investigate the effect of KyoT2 on the proliferation and migration of airway smooth muscle cells (ASMCs) in mice with asthma.

METHODS

Ovalbumin (OVA) was used to establish the asthmatic model of airway remodeling in BALB/c mice. ASMCs were isolated and cultured, and primarily cultured ASMCs were used as the control group. The expression of KyoT2 in ASMCs was measured in the control and asthma groups. After the ASMCs from asthmatic mice were transfected with pCMV-Myc (empty vector group) or pCMV-Myc-KyoT2 plasmid with overexpressed KyoT2 (KyoT2 expression group) for 48 hours, RT-PCR and Western blot were used to measure the mRNA and protein expression of KyoT2, the MTT assay and BrdU assay were used to measure the proliferation of ASMCs, and Transwell assay was used to measure the migration of ASMCs. Western blot was used to determine the effect of KyoT2 overexpression on the protein expression of RBP-Jκ, PTEN, and AKT.

RESULTS

Compared with the control group, the asthma group had significantly downregulated expression of KyoT2 in ASMCs, and the KyoT2 expression group had significantly upregulated expression of KyoT2 in ASMCs (P<0.05). Compared with the empty vector group, overexpressed KyoT2 significantly inhibited cell proliferation and migration, downregulated the expression of RBP-Jκ and AKT, and upregulated the expression of PTEN.

CONCLUSIONS

Overexpressed KyoT2 can inhibit the proliferation and migration of ASMCs through the negative regulation of RBP-Jκ/PTEN/AKT signaling pathway.

[Effect of phosphoinositide 4-phosphate on invasion and migration of human glioma U87 cells]

OBJECTIVE

To investigate the effect of phosphoinositide 4-phosphate (PI4P) on human glioma U87 cells and the mechanism of action of PI4P in the development of human glioma through the overexpression or silencing of PI4P in human glioma U87 cells, and to provide a new target for basic research and clinical treatment of glioma.

METHODS

LV-Helper1, LV-Helper2, pWPXLd-PI4P, and pLL3.7-shPI4P were used to package pWPXLd-PI4P and pLL3.7-shPI4P lentiviruses. The U87-GFP (PI4P-overexpression control group), U87-GFP-PI4P (PI4P-overexpression experimental group), U87-Scramble (PI4P-silencing control group), and U87-shPI4P (PI4P-silencing experimental group) cell lines were established. Wound-healing assay and Transwell assay were used to evaluate cell migration and invasion, and Western blot was used to measure the expression of PI4P in each group.

RESULTS

Western blot detected the expression of exogenous PI4P in the U87-GFP-PI4P cell line, and the U87-shPI4P cell line showed reduced expression of PI4P compared with the U87-Scramble cell line in the control group. The U87-GFP-PI4P cell line with PI4P overexpression had a significantly stronger ability of migration than the U87-GFP cell line in the control group (P<0.01); the U87-shPI4P cell line with PI4P silencing had a reduced ability of migration than the U87-Scramble cell line in the control group (P<0.01). The U87 cell line with PI4P overexpression had a significantly stronger invasion ability than the control group (P<0.05); after PI4P silencing, the experimental group showed a significant reduction in invasion ability compared with the control group (P<0.05).

CONCLUSIONS

In human glioma U87 cells, PI4P can promote the invasion and migration of glioma cells and may become a new target in the basic research and clinical treatment of glioma.

[The Supernatant Obtained from Cultured Anip973 Cells Enhances the Biological Activities of HUVEC]

BACKGROUND AND OBJECTIVE

Unlike normal tissue-derived microvascular endothelial cells, tumor microvessel endothelial cells are highly reactive to growth factors and exhibit more adhesion molecules. Thus, vascular tumors are highly permeable and grow vigorously; this occurrence results in rapid growth and metastasis cancer cells. Therefore, understanding the characteristics of endothelial cells in the tumor microenvironment guides anti-angiogenic therapy. To this end, we explore the effect of the supernatant obtained from cultured Anip973 cells (high-metastatic human lung adenocarcinoma cells) on the biological behavior and on the cell surface markers of the human umbilical vein endothelial cell (HUVEC).

METHODS

The HUVEC that was cultured in a medium (RPMI-1640 + 10% fetal bovine serum) containing various concentrations of Anip973 supernatants was categorized into experimental groups. The HUVEC cultured in a medium without Anip973 supernatants served as the control group. Proliferation was determined with CCK-8; blood vessel formation was investigated with three-dimensional culture techniques in vitro; and HUVEC migration was observed via transwell assay. At the same time, the expressions of CD105, CD31, and the apoptotic marker of Annexin V were detected through flow cytometry for analyzing the relationship between the expression of cell surface markers and biological behavior.

RESULTS

Following incubation with the supernatant obtained from cultured Anip973 cells, HUVEC proliferated more than the control group did, and the proliferation rate was maximized when incubated in a supernatant concentration of 250 μL/mL for 24 h (P=0.002). In addition, the experimental groups exhibited varying degrees of migration and forms of vascular lumen sample structure, especially at supernatant concentrations of 125 µL/mL (P<0.001) and 250 µL/mL (P=0.002), respectively. CD105 expression was optimized at 250 μL/mL (P=0.028), and CD31 expression also increased with an increase in concentration. However, the percentage of apoptotic cells decreased. Correlation analysis results showed that cell proliferation, migration, and CD105 expression were significantly and positively correlated with one another. By contrast, no significant correlation was detected between CD31 expression and biological behavior.

CONCLUSIONS

Anip973 supernatants can promote HUVEC proliferation and migration, as well as angiogenesis. In addition, cell surface markers can change concurrently and relatively. To a certain extent, changes in CD105 expression can be attributed to shifts in its biological behavior.
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Slit2/Robo1 signaling in glioma migration and invasion

Slit2/Robo1 is a conserved ligand-receptor system, which greatly affects the distribution, migration, axon guidance and branching of neuron cells. Slit2 and its transmembrane receptor Robo1 have different distribution patterns in gliomas. The expression of Slit2 is at very low levels in pilocytic astrocytoma, fibrillary astrocytoma and glioblastoma, while Robo1 is highly expressed in different grades of gliomas at both mRNA and protein levels. Acquisition of insidious invasiveness by malignant glioma cells involves multiple genetic alterations in signaling pathways. Although the specific mechanisms of tumor-suppressive effect of Slit2/Robo1 have not been elucidated, it has been proved that Slit2/Robo1 signaling inhibits glioma cell migration and invasion by inactivation of Cdc42-GTP. With the research development on the molecular mechanisms of Slit2/Robo1 signaling in glioma invasion and migration, Slit2/Robo1 signaling may become a potential target for glioma prevention and treatment.