• Asian Pacific Journal of Cancer Prevention
• /
• v.17 no.7
• /
• pp.3437-3445
• /
• 2016

Background: There is an increasing concern in the role of microRNA (miRNA) in the pathogenesis of bone metastasis (BM) secondary to prostate cancer (CaP). In this exploratory study, we hypothesized that the expression of vinculin (VCL) and chemokine X3C ligand 1 (CX3CL1) might be down-regulated in clinical samples, most likely due to the post-transcriptional modification by microRNAs. Targeted genes would be up-regulated upon transfection of the bone metastatic prostate cancer cell line, PC3, with specific microRNA inhibitors. Materials and Methods: MicroRNA software predicted that miR-21 targets VCL while miR-29a targets CX3CL1. Twenty benign prostatic hyperplasia (BPH) and 16 high grade CaP formalin-fixed paraffin embedded (FFPE) specimens were analysed. From the bone scan results, high grade CaP samples were further classified into CaP with no BM and CaP with BM. Transient transfection with respective microRNA inhibitors was done in both RWPE-1 (normal) and PC3 cell lines. QPCR was performed in all FFPE samples and transfected cell lines to measure VCL and CX3CL1 levels. Results: QPCR confirmed that VCL messenger RNA (mRNA) was significantly down-regulated while CX3CL1 was up-regulated in all FFPE specimens. Transient transfection with microRNA inhibitors in PC3 cells followed by qPCR of the targeted genes showed that VCL mRNA was significantly upregulated while CX3CL1 mRNA was significantly down-regulated compared to the RWPE-1 case. Conclusions: The down-regulation of VCL in FFPE specimens is most likely regulated by miR-21 based on the in vitro evidence but the exact mechanism of how miR-21 can regulate VCL is unclear. Up-regulated in CaP, CX3CL1 was found not regulated by miR-29a. More microRNA screening is required to understand the regulation of this chemokine in CaP with bone metastasis. Understanding miRNA-mRNA interactions may provide additional knowledge for individualized study of cancers.

• The Korean Journal of Physiology
• /
• v.28 no.1
• /
• pp.51-59
• /
• 1994

This study was carried out to elucidate the excitatory mechanisms of Substance P in the antral circular muscle, using isometric contraction recording, conventional microelectrode method and whole-cell patch clamp technique. Substance P produced tonic and phasic contractions in a dose-dependent manner and depolarized membrane potential with increased amplitude of slow waves in muscle strips. Voltage-dependent $Ca^{2+}$ currents were increased by the application of Substance P from a holding potential of -60mV to 50mV in 10mV steps and this effect was blocked by the addition of an antagonist. Also Substance P increased transient and spontaneous oscillatory $K^+$ outward currents. The enhanced outward currents were abolished by apamin in dispersed single cells. These results suggest that the depolarization of membrane potential by Substance P activates voltage-dependent $Ca^{2+}$ channels, which represents an excitatory response in the antral circular muscle and led to an increase in $Ca^{2+}\;activated\;K^+\;currents$.

• The Korean Journal of Physiology
• /
• v.24 no.2
• /
• pp.377-388
• /
• 1990

Ca movements during the late plateau phase in rabbit atrium implicate Na-Ca exchange. In single atrial cells isolated from the rabbit the properties of the inward current of Na-Ca exchange were investigated using the whole cell voltage clamp technique. The inward currents were recorded during repolarization following brief 2 ms depolarizing pulse to +40 mV from a holding potential of -70 mV. Followings are the results obtained: 1) When stimulated every 30 sec, the inward currents were activated and reached peak values $6{\sim}12\;ms$ after the beginning of depolarizing pulse. The mean current amplitude was 342 pA/cell. 2) The current decayed spontaneously from the peak activation and the timecourse of the relaxation showed two different phases: fast and slow phase. 3) The recovery of the inward current was tested by paired pulse of various interval. The peak current recovered exponentialy with a time course similar to that of Ca current recovery. 4) Relaxation timecourse was also affected by pulse interval and time constant was reduced almost linearly according to the decrease of pulse interval between 30 sec and 1 sec. 5) The peak inward current was increased by long prepulse stimulation, Bay K, isoprenaline or c-AMP. 6) The relaxation time constant of the inward current was prolonged by Bay K or c-AMP, and shortened by isoprenaline. From the above results, it could be concluded that increase of the calcium current potentiates and prolongs intracellular calcium transients, while shortening of the timecourse by isoprenaline or short interval stimulations might be due to the facilitation of Ca uptake by SR.

• International Journal of Oral Biology
• /
• v.46 no.3
• /
• pp.134-139
• /
• 2021

Under physiological conditions, calcium (Ca²⁺) regulates essential functions of polarized secretory cells by the stimulation of specific Ca²⁺ signaling mechanisms, such as increases in intracellular Ca²⁺ concentration ([Ca²⁺]_i) via the store-operated Ca²⁺ entry (SOCE) and the receptor-operated Ca²⁺ entry (ROCE). Homer proteins are scaffold proteins that interact with G protein-coupled receptors, inositol 1,4,5-triphosphate (IP₃) receptors, Orai1-stromal interaction molecule 1, and transient receptor potential canonical (TRPC) channels. However, their role in the Ca²⁺ signaling in exocrine cells remains unknown. In this study, we investigated the role of Homer2 in the Ca²⁺ signaling and regulatory channels to mediate SOCE and ROCE in pancreatic acinar cells. Deletion of Homer2 (Homer2^-/-) markedly increased the expression of TRPC3, TRPC6, and Orai1 in pancreatic acinar cells, whereas these expressions showed no difference in whole brains of wild-type and Homer2^-/- mice. Furthermore, the response of Ca²⁺ entry by carbachol also showed significant changes to the patterns regulated by specific blockers of SOCE and ROCE in pancreatic acinar cells of Homer2^-/- mice. Thus, these results suggest that Homer2 plays a critical role in the regulatory action of the [Ca²⁺]_i via SOCE and ROCE in mouse pancreatic acinar cells.

• International Journal of Oral Biology
• /
• v.46 no.4
• /
• pp.176-183
• /
• 2021

Oral squamous cell carcinoma (OSCC) metastasis is characterized by distant metastasis and local recurrence. Combined chemotherapy with cisplatin and 5-fluorouracil is routinely used to treat patients with OSCC, and the combined use of gefitinib with cytotoxic drugs has been reported to enhance the sensitivity of cancer cells in vitro. However, the development of drug resistance because of prolonged chemotherapy is inevitable, leading to a poor prognosis. Therefore, understanding alterations in signaling pathways and gene expression is crucial for overcoming the development of drug resistance. However, the altered characterization of Ca²⁺ signaling in drug-resistant OSCC cells remains unclear. In this study, we investigated alterations in intracellular Ca²⁺ ([Ca²⁺]_i) mobilization upon the development of gefitinib resistance in human tongue squamous carcinoma cell line (HSC)-3 and HSC-4 using ratiometric analysis. This study demonstrated the presence of altered epidermal growth factor- and purinergic agonist-mediated [Ca²⁺]_i mobilization in gefitinib-resistant OSCC cells. Moreover, Ca²⁺ content in the endoplasmic reticulum, store-operated calcium entry, and lysosomal Ca²⁺ release through the transient receptor potential mucolipin 1, were confirmed to be significantly reduced upon the development of apoptosis resistance. Consistent with [Ca²⁺]_i mobilization, we identified modified expression levels of Ca²⁺ signaling-related genes in gefitinib-resistant cells. Taken together, we propose that the regulation of [Ca²⁺]_i mobilization and related gene expression can be a new strategy to overcome drug resistance in patients with cancer.

• Journal of Korean Society for Atmospheric Environment
• /
• v.28 no.1
• /
• pp.39-51
• /
• 2012

Aerosol slurry samples were collected in 60-min interval using Korean Semi-continuous Elements in Aerosol Sampler (KSEAS) between May 19 and June 6, 2010 at an urban site of Gwangju. The $PM_{2.5}$ samples were collected with a flow rate of 16.7 L/min and particles are grown by condensation of water vapor in a condenser maintained at ${\sim}5^{\circ}C$ after saturation by direct injection of steam. The resulting droplets are collected in a liquid slurry with a airdroplet separator. Concentrations of 16 elements (Al, Fe, Mn, Ca, K, Cu, Zn, Pb, Cd, Cr, Ti, V, Ni, Co, As, Se) in the collected slurry samples were determined off-line by ICP-MS. KSEAS sample analysis encompassed the sampling periods for which 24-hr average elemental species concentrations were calculated for comparison with those derived from 24-hr integrated filter samples. Relationship between elemental species measured by two methods indicated high correlation coefficients (r), mostly greater than r of 0.80. However, we note that concentrations of Al, K, Ca, Mn, and Fe, which are often associated with crustal elemental particles, in the KSEAS samples, were substantially lower (1.4~11 times) than those found in the typical filter-based samples. This discrepancy is probably due to difficulties in transferring insoluble dust particles to the collection vials in the KSEAS. Temporal profiles of elemental concentrations indicate that some transient events in their concentrations are observed over the sampling periods. For the elemental species studied, atmospheric concentrations during the transient events increased by factors of 4 in Mn~80 in Zn, compared to their background levels. Principle component analyses were applied to the hourly KSEAS data sets to identify sources affecting the concentrations of the metal constituents observed. In this study, we conclude that hourly measurements for particle-bound elemental constituents were extremely useful for revealing the short-term variability in their concentrations and developing insights into their sources.

• International Journal of Oral Biology
• /
• v.45 no.2
• /
• pp.58-63
• /
• 2020

The salivary glands secrete saliva, which plays a role in the maintenance of a healthy oral environment. Under physiological conditions, saliva secretion within the acinar cells of the gland is regulated by stimulation of specific calcium (Ca²⁺) signaling mechanisms such as increases in the intracellular Ca²⁺ concentration ([Ca²⁺]_i) via storeoperated Ca²⁺ entry, which involves components such as Orai1, transient receptor potential (TRP) canonical 1, stromal interaction molecules, and inositol 1,4,5-triphosphate (IP₃) receptors (IP₃Rs). Homer proteins are scaffold proteins that bind to G protein-coupled receptors, IP₃Rs, ryanodine receptors, and TRP channels. However, their exact role in Ca²⁺ signaling in the salivary glands remains unknown. In the present study, we investigated the role of Homer2 in Ca²⁺ signaling and saliva secretion in parotid gland acinar cells under physiological conditions. Deletion of Homer2 (Homer2^-/-) markedly decreased the amplitude of [Ca²⁺]_i oscillations via the stimulation of carbachol, which is physiologically concentrated in parotid acinar cells, whereas the frequency of [Ca²⁺]_i oscillations showed no difference between wild-type and Homer2^-/- mice. Homer2^-/- mice also showed a significant decrease in amylase release by carbachol in the parotid gland in a dose-dependent manner. These results suggest that Homer2 plays a critical role in maintaining [Ca²⁺]_i concentration and secretion of saliva in mouse parotid gland acinar cells.

• The Korean Journal of Physiology and Pharmacology
• /
• v.15 no.3
• /
• pp.179-187
• /
• 2011

Regulation of B cell receptor (BCR)-induced $Ca^{2+}$ signaling by CD40 co-stimulation was compared in long-term BCR-stimulated immature (WEHI-231) and mature (Bal-17) B cells. In response to long-term pre-stimulation of immature WEHI-231 cells to ${\alpha}$-IgM antibody (0.5~48 hr), the initial transient decrease in BCR-induced $[Ca^{2+}]_i$ was followed by spontaneous recovery to control level within 24 hr. The recovery of $Ca^{2+}$ signaling in WEHI-231 cells was not due to restoration of internalized receptor but instead to an increase in the levels of $PLC{\gamma}2$ and $IP_3R-3$. CD40 co-stimulation of WEHI-231 cells prevented BCR-induced cell cycle arrest and apoptosis, and it strongly inhibited the recovery of BCR-induced $Ca^{2+}$ signaling. CD40 co-stimulation also enhanced BCR internalization and reduced expression of $PLC{\gamma}2$ and $IP_3R-3$. Pre-treatment of WEHI-231 cells with the antioxidant N-acetyl-L-cysteine (NAC) strongly inhibited CD40-mediated prevention of the recovery of $Ca^{2+}$ signaling. In contrast to immature WEHI-231 cells, identical long-term ${\alpha}$-IgM pre-stimulation of mature Bal-17 cells abolished the increase in BCR-induced $[Ca^{2+}]_i$, regardless of CD40 co-stimulation. These results suggest that CD40-mediated signaling prevents antigen-induced cell cycle arrest and apoptosis of immature B cells through inhibition of sustained BCR-induced $Ca^{2+}$ signaling.

• Horticultural Science & Technology
• /
• v.31 no.1
• /
• pp.38-49
• /
• 2013

Prohexadione-calcium (Pro-Ca), ethephon and transient water stress were evaluated in a factorial design, as potential inhibitors of early-season shoot growth of high density orchard management of apple (Malus domestica Borkh.) trees. In the experiment, water stress was imposed to one-half of the 7-year-old 'Golden Delicious'/M.9 apple trees in each of 5 blocks, by stopping irrigation for 3 weeks between 35 and 56 days after full bloom (AFB). Within each whole unit, the following Pro-Ca and ethephon treatments were randomly allocated at $2{\times}2$ factorial: a) 0 or 250 $mg{\cdot}L^{-1}$ a.i. Pro-Ca applied at 28 days AFB and b) 0 or 300 $mg{\cdot}L^{-1}$ a.i. ethephon applied twice (35 and 71 days AFB). All trees were hand thinned to king flowers prior to treatments. Vegetative shoot growth was markedly reduced by Pro-Ca, with its effect being obvious within 14 days after application, while ethephon and water stress treatments were less effective. Pro-Ca had no effect on fruit set and yield but slightly increased fruit size. Ethephon substantially reduced the fruit size and yield but had no effect on fruit set. Water stress reduced fruit set, fruit size and yield. With regard to fruit quality, Pro-Ca did not influence fruit shape, flesh firmness and soluble solids contents (SSC) but slightly reduced titratable acidity. Ethephon had no effect on fruit shape but increased firmness, SSC and acidity, while water stress did not influence these fruit quality attributes. Dry weight of dormant spur buds was reduced by both Pro-Ca and water stress, while increased by ethephon. The larger dormant buds led to the larger spur flowers at the tight cluster stage the following spring. Return flowering was promoted only by ethephon, especially on previous season's shoots. There were no significant interactions between Pro-Ca and ethephon or water stress on most variables observed in this study.

• Journal of Plant Biology
• /
• v.37 no.1
• /
• pp.77-83
• /
• 1994

DNA uptake in dry embryos of rice by DNA imbibition was detected by monitoring the expression of chimeric vectors. The selective markers of expression vectors used were ${\beta}-glucuronidase$ ronidase (GUS) and hygromycin phosphotransferase (HPT) genes under the control of CaMV35 S promoter. Frequency of transient expression of the foreign gene was generally 30-50% varying according to the types of vectors and rice cultivars. Dot blot analysis and DNA sequence analysis of inverse polymerase chain reaction products showed that selected rice in hygromycin B (HmB) medium had HPT gene and CaMV35S promoter DNA sequence in genomic DNA of rice. To investigate what ratio of rice having two marker genes simultaneously as rice embryos imbibed the vector DNA having two HPT and GUS gene, transform ants selected in lImB medium were subjected to PCR for GUS gene. It was shown that about 90 percentage of surviving ones in HmB medium had GUS gene.S gene.