Ultraviolet-B (UV-B) is a relatively minor component of sunlight, but can induce stress-related physiological processes or UV-B-specific photomorphogenic responses in plants. In the last decade, significant progress has been made in understanding the UV-B photomorphogenic pathway, including identification of the key components in the pathway, molecular characterization of UV-B photoreceptor and perception mechanism, and elucidation of the signal transduction mechanisms from the photoactivated UV-B receptor to downstream gene expression. This review summarizes the key players identified to date in the UV-B photomorphogenic pathway and their roles in mediating UV-B signal transduction.
Arabidopsis ; cytology ; growth & development ; radiation effects ; Plant Development ; radiation effects ; Plant Proteins ; metabolism ; Signal Transduction ; radiation effects ; Ultraviolet Rays

OBJECTIVEPancreatic cancer is a highly aggressive malignancy that has been resistant to treatment. Advances in cancer genetics have improved our understanding of this disease, but the genetics of pancreatic cancer remain poorly understood. A better understanding of the pathogenic role of specific gene mutations and core signaling pathways would propel the development of more effective treatments. The objective in this review was to highlight recent research that shows promise for new treatments for pancreatic cancer.

DATA SOURCESAll articles cited in this review were mainly searched from PubMed, which were published in English from 1993 to 2009.

STUDY SELECTIONOriginal articles and critical reviews selected were relevant to the molecular mechanisms of pancreatic cancer.

RESULTSDysregulation of core signaling pathways and processes through frequently genetic alterations can explain the major features of pancreatic tumorigenesis. New therapeutic targets based on recent research are emerging that hold promise for the future management of pancreatic cancer.

CONCLUSIONNew agents used in conjunction with standard radiotherapy and chemotherapy might help to overcome drug resistance by targeting multiple signaling pathways to induce responsiveness of pancreatic cancer cells to death signals.

Humans ; Pancreatic Neoplasms ; drug therapy ; metabolism ; radiotherapy ; Signal Transduction ; drug effects ; radiation effects

This study investigated that whether a 2 mT, 60 Hz, sinusoidal electromagnetic field (EMF) alters the structure and function of cells. This research compared the effects of EMF on four kinds of cell lines: hFOB 1.19 (fetal osteoblast), T/G HA-VSMC (aortic vascular smooth muscle cell), RPMI 7666 (B lymphoblast), and HCN-2 (cortical neuronal cell). Over 14 days, cells were exposed to EMF for 1, 3, or 6 hours per day (hrs/d). The results pointed to a cell type-specific reaction to EMF exposure. In addition, the cellular responses were dependent on duration of EMF exposure. In the present study, cell proliferation was the trait most sensitive to EMF. EMF treatment promoted growth of hFOB 1.19 and HCN-2 compared with control cells at 7 and 14 days of incubation. When the exposure time was 3 hrs/d, EMF enhanced the proliferation of RPMI 7666 but inhibited that of T/G HA- VSMC. On the other hand, the effects of EMF on cell cycle distribution, cell differentiation, and actin distribution were unclear. Furthermore, we hardly found any correlation between EMF exposure and gap junctional intercellular communication in hFOB 1.19. This study revealed that EMF might serve as a potential tool for manipulating cell proliferation.
Signal Transduction ; Microfilaments/radiation effects ; Humans ; Gap Junctions/metabolism/radiation effects ; *Electromagnetic Fields ; Cell Proliferation/radiation effects ; Cell Physiology/*radiation effects ; Cell Line ; Cell Differentiation/radiation effects ; Cell Cycle/radiation effects

This study investigated that whether a 2 mT, 60 Hz, sinusoidal electromagnetic field (EMF) alters the structure and function of cells. This research compared the effects of EMF on four kinds of cell lines: hFOB 1.19 (fetal osteoblast), T/G HA-VSMC (aortic vascular smooth muscle cell), RPMI 7666 (B lymphoblast), and HCN-2 (cortical neuronal cell). Over 14 days, cells were exposed to EMF for 1, 3, or 6 hours per day (hrs/d). The results pointed to a cell type-specific reaction to EMF exposure. In addition, the cellular responses were dependent on duration of EMF exposure. In the present study, cell proliferation was the trait most sensitive to EMF. EMF treatment promoted growth of hFOB 1.19 and HCN-2 compared with control cells at 7 and 14 days of incubation. When the exposure time was 3 hrs/d, EMF enhanced the proliferation of RPMI 7666 but inhibited that of T/G HA- VSMC. On the other hand, the effects of EMF on cell cycle distribution, cell differentiation, and actin distribution were unclear. Furthermore, we hardly found any correlation between EMF exposure and gap junctional intercellular communication in hFOB 1.19. This study revealed that EMF might serve as a potential tool for manipulating cell proliferation.
Signal Transduction ; Microfilaments/radiation effects ; Humans ; Gap Junctions/metabolism/radiation effects ; *Electromagnetic Fields ; Cell Proliferation/radiation effects ; Cell Physiology/*radiation effects ; Cell Line ; Cell Differentiation/radiation effects ; Cell Cycle/radiation effects

Objective: The expression patterns of ribosomal large subunit protein 23a (RPL23a) in mouse testes and GC-1 cells were analyzed to investigate the potential relationship between RPL23a expression and spermatogonia apoptosis upon exposure to X-ray. Methods: Male mice and GC-1 cells were irradiated with X-ray, terminal dUTP nick end-labelling (TUNEL) was performed to detect apoptotic spermatogonia Results: Ionizing radiation (IR) increased spermatogonia apoptosis, the expression of RPL11, MDM2 and p53, and decreased RPL23a expression in mice spermatogonia Conclusion These results suggested that IR reduced RPL23a expression, leading to weakened the RPL23a-RPL11 interactions, which may have activated p53, resulting in spermatogonia apoptosis. These results provide insights into environmental and clinical risks of radiotherapy following exposure to IR in male fertility. The graphical abstract was available in the web of www.besjournal.com.
Animals ; Apoptosis/genetics* ; Gene Expression Regulation ; Male ; Mice ; Ribosomal Proteins/metabolism* ; Signal Transduction ; Spermatogonia/radiation effects*

Low-intensity pulsed ultrasound (LIPUS) is a promising therapy that has been increasingly explored in basic research and clinical applications. LIPUS is an appealing therapeutic option as it is a noninvasive treatment that has many advantages, including no risk of infection or tissue damage and no known adverse reactions. LIPUS has been shown to have many benefits including promotion of tissue healing, angiogenesis, and tissue regeneration; inhibition of inflammation and pain relief; and stimulation of cell proliferation and differentiation. The biophysical mechanisms of LIPUS remain unclear and the studies are ongoing. In recent years, more and more research has focused on the relationship between LIPUS and stem/progenitor cells. A comprehensive search of the PubMed and Embase databases to July 2020 was performed. LIPUS has many effects on stem cells. Studies show that LIPUS can stimulate stem cells in vitro; promote stem cell proliferation, differentiation, and migration; maintain stem cell activity; alleviate the problems of insufficient seed cell source, differentiation, and maturation; and circumvent the low efficiency of stem cell transplantation. The mechanisms involved in the effects of LIPUS are not fully understood, but the effects demonstrated in studies thus far have been favorable. Much additional research is needed before LIPUS can progress from basic science research to large-scale clinical dissemination and application.
Cell Proliferation ; Humans ; Signal Transduction ; Stem Cells/radiation effects* ; Ultrasonic Therapy/methods* ; Ultrasonic Waves

OBJECTIVETo observe the effect of mitogen activated protein kinase (MAPK) signal transduction system on the apoptosis induced by electromagnetic exposure in PC12 cells.

METHODSAfter pretreated by SB203580 alone or together with U0126, PC12 cells were exposed to 65 mW/cm(2) electromagnetic wave for 20 min. The phosphorylations of ERK1/2, JNK and P38 MAPK were tested by Western-blot at 3 h and 24 h after electromagnetic exposure. The apoptosis of PC12 cells were detected by Annexin-V-FITC flow cytometry.

RESULTSU0126, but not SB203580 could inhibit the activation of ERK1/2 induced by electromagnetic exposure. U0126 and SB203580 had no effects on the activation of JNK. SB203580 could inhibit the activation of P38 MAPK significantly. But U0126 had no such effect on the activation of P38 MAPK. After pretreated by SB203580 alone or together with U0126, the apoptosis of PC12 cells decreased. But the pretreatment by U0126 alone had no influence on the apoptosis of PC12 cells.

CONCLUSIONThe P38 MAPK signal transduction modulate the apoptosis of PC12 cells induced by electromagnetic exposure. ERK signal transduction has no effect on the apoptosis of PC12 cells. JNK signal transduction may promote the apoptosis of PC12 cells in the early stage after electromagnetic exposure.

Animals ; Apoptosis ; radiation effects ; Electromagnetic Radiation ; Mitogen-Activated Protein Kinases ; metabolism ; PC12 Cells ; Phosphorylation ; Rats ; Signal Transduction

Cells, Cultured ; Curcumin ; pharmacology ; Endothelium, Vascular ; drug effects ; pathology ; radiation effects ; Human Umbilical Vein Endothelial Cells ; drug effects ; radiation effects ; Humans ; Radiation Injuries ; Signal Transduction ; drug effects ; radiation effects

OBJECTIVETo explore the correlation of low-dose radiation with endoplasmic reticulum stress and the activation of the PERK-CHOP signaling pathway in mouse testicular cells.

METHODSHealthy Kunming mice were randomly assigned to time-effect (0, 3, 6, 12 and 24 h of irradiation at 75 mGy) and dose-effect (12 h of irradiation at 0, 50, 75, 100 and 200 mGy) groups. The contents of H202 and MDA were measured by colorimetry with the agent kits, the expressions of GRP78, PERK and CHOP mRNA detected by quantitative RT-PCR, and the levels of GRP7B, PERK, phosphorylated PERK (pho-PERK) and CHOP proteins determined by Western blotting and image analysis.

RESULTSAfter whole-body irradiation of the mice with 75 mGy, the content of H2 02 in the testis tissue was increased with time prolongation, while that of MDA decreased slightly at 3 and 6 h and then increased with the lengthening of time, both increased significantly at 12 and 24 h as compared with those at 0 h (P < 0. 05, P < 0. 01). Apart from reduced levels of GRP78 mRNA at 3 and 24 h and GRP78 protein at 6 h after irradiation, significant increases were found in the mRNA expressions of GRP78 at 12 h, PERK at 3,6, 12 and 24 hand CHOP at 12 and 24 h (P < 0.05, P < 0.01), as well as in the protein levels of GRP78 at 12 and 24 h, pho-PERK at 3, 12 and 24 h and CHOP at 3, 6, 12 and 24 h in comparison with those at 0 h (P < 0. 05, P < 0. 01). No obvious regularity was observed in the change of the PERK protein expression. After 12 h of whole-body irradiation, the content of H202 was increased at 50, 75 and 100 mGy, but decreased slightly at 200 mGy, while that of MDA was increased with dose increasing, with significant increases in the content of H2 02 at 75 and 100 mCy and in that of MDA at 75, 100 and 200 mGy as compared with the 0 mGy group. Apart from the reduced levels of GRP78 mRNA at 50 and 200 mCy, significant increases were found in the mRNA expressions of PERK at 75, 100 and 200 mGy and CHOP at 50, 75, 100 and 200 (P c 0. 05, P < 0.01) as well as in the protein levels of GRP78 at 100 and 200 mGy, pho-PERK at 50, 100 and 200 mGy and CHOP at 50, 75, 100 and 200 mCy as compared with those at 0 mGy (P < 0. 05, P < 0. 01). There were differences in the changes of different protein expressions, but no obvious regularity was seen in the change of the PERK protein expression.

CONCLUSIONLow-dose radiation can induce endoplasmic reticulum stress in mouse testicular cells, and activate the PERK-CHOP signaling pathway.

Animals ; Endoplasmic Reticulum Stress ; radiation effects ; Heat-Shock Proteins ; metabolism ; Male ; Mice ; Mice, Inbred Strains ; Radiation Dosage ; Radiation, Ionizing ; Signal Transduction ; radiation effects ; Testis ; cytology ; metabolism ; radiation effects ; Transcription Factor CHOP ; metabolism ; Whole-Body Irradiation ; eIF-2 Kinase ; metabolism

OBJECTIVETo investigate the relationship among a 50 Hz magnetic field (MF)-induced epidermal growth factor receptor (EGFR) clustering,lipid rafts and acid sphingomyelinase (ASM), and to explore its possible mechanism.

METHODSHuman amnion FL cells were exposed to 50 Hz, 0.4 mT MF for 15 min. EGF treatment was used as positive control. Nystatin was employed to study lipid rafts since it could disrupt lipid rafts structure.The EGF receptors, ASM and lipid rafts were labeled with polyclonal anti-EGFR antibody, anti-ASM antibody and FITC-Cholera toxin B, respectively. The images were observed by laser confocal scanning microscope.

RESULTBoth EGF treatment and 50 Hz MF exposure could induce EGFR clustering; however, nystatin pretreatment disrupted this effect. MF exposure turned ASM (labeled with Cy3) from a diffused state in the sham exposure group to a concentrated state on the cell membrane, which co-localized with lipid rafts (labeled with FITC).

CONCLUSIONThe results suggest that the EGFR clustering induced by 50 Hz MF depends on intact lipid rafts on cellular membrane, and the ASM might participate in the process of EGFR clustering.

Cell Membrane ; radiation effects ; Cells, Cultured ; Electromagnetic Fields ; Epidermal Growth Factor ; metabolism ; Humans ; Membrane Microdomains ; radiation effects ; Receptor, Epidermal Growth Factor ; metabolism ; radiation effects ; Signal Transduction ; physiology ; radiation effects ; Sphingomyelin Phosphodiesterase ; metabolism