OBJECTIVE: To investigate the effect of PPP2R5C to the activity of Molt-4 cells in childhood acute T lymphocytic leukemia and its mechanism. METHODS: The small interfering RNA (siRNA) technology targeting PPP2R5C gene was used to down-regulate the expression of PPP2R5C in Molt-4 cells. At the same time, a blank control group, a negative control group and a 17-DMAG group were set up. The cells in the negative control group were transfected with siRNA-NC, the cells in 17-DMAG group were treated with the HSP90 inhibitor 17-DMAG at a final concentration of 6.4 μmol/L for 48 h. Real-time fluorescent quantitative PCR (RT-qPCR) and Western blot were used to detect transfection efficiency; CCK-8 method was used to detect the proliferation activity of the cells in each group, EdU was used to detect the proliferation level of the cells in each group, flow cytometry was used to detect the cell cycle distribution ratio of the cells in each group, Annexin V-FITC/PI staining was used to detect the apoptosis of the cell, RT-qPCR and Western blot were used to detect the expression changes of heat shock protein 90 (HSP90) and glucocorticoid receptor (GR) of the cells in each group. RESULTS: After Molt-4 cells were transfected with siRNA-PPP2R5C, the expression of PPP2R5C mRNA and protein in the cells were down-regulated significantly compared with those in the blank control group and the si-NC group (P<0.05); compared with cells in the blank control group and the si-NC group, the proliferation activity of the cells in the siRNA-PPP2R5C group and the 17-DMAG group significantly decreased (P<0.05), and the rate of EdU positive cells was significantly reduced (P<0.05); the proportion of the cells in G1 phase decreased while the proportion of the cells in G₂ phase increased (P<0.05), the apoptosis rate of the cells also increased significantly (P<0.05); in addition, the expression of PPP2R5C mRNA and protein of the cells in siRNA-PPP2R5C group was significantly down-regulated compared with those in the blank control group and si-NC group (P<0.05). The expressions of PPP2R5C mRNA and protein in the 17-DMAG group were also significantly down-regulated compared with those in the blank control group and si-NC group (P<0.05). CONCLUSION Down-regulation of PPP2R5C gene expression can inhibit Molt-4 cell activity in childhood acute T lymphocytic leukemia, block the cells in G₂ phase, and promote cell apoptosis, the mechanism may be related to the inhibition of HSP90-GR signaling pathway.
Apoptosis ; Cell Line, Tumor ; Cell Proliferation ; Cell Survival ; Child ; HSP90 Heat-Shock Proteins ; Humans ; Precursor T-Cell Lymphoblastic Leukemia-Lymphoma ; RNA, Small Interfering ; Receptors, Glucocorticoid

The expression of BCL-2 interacting cell death suppressor (BIS), an anti-stress or anti-apoptotic protein, has been shown to be regulated at the transcriptional level by heat shock factor 1 (HSF1) upon various stresses. Recently, HSF1 was also shown to bind to BIS, but the significance of these protein-protein interactions on HSF1 activity has not been fully defined. In the present study, we observed that complete depletion of BIS using a CRISPR/Cas9 system in A549 non-small cell lung cancer did not affect the induction of heat shock protein (HSP) 70 and HSP27 mRNAs under various stress conditions such as heat shock, proteotoxic stress, and oxidative stress. The lack of a functional association of BIS with HSF1 activity was also demonstrated by transient downregulation of BIS by siRNA in A549 and U87 glioblastoma cells. Endogenous BIS mRNA levels were significantly suppressed in BIS knockout (KO) A549 cells compared to BIS wild type (WT) A549 cells at the constitutive and inducible levels. The promoter activities of BIS and HSP70 as well as the degradation rate of BIS mRNA were not influenced by depletion of BIS. In addition, the expression levels of the mutant BIS construct, in which 14 bp were deleted as in BIS-KO A549 cells, were not different from those of the WT BIS construct, indicating that mRNA stability was not the mechanism for autoregulation of BIS. Our results suggested that BIS was not required for HSF1 activity, but was required for its own expression, which involved an HSF1-independent pathway.
Carcinoma, Non-Small-Cell Lung* ; Cell Death ; Down-Regulation ; Glioblastoma ; Heat-Shock Proteins ; Homeostasis ; Hot Temperature ; Oxidative Stress ; RNA Stability ; RNA, Messenger ; RNA, Small Interfering ; Shock ; Transcriptional Activation*

BACKGROUND: The mesenchymal-epithelial transition factor (MET) receptor can be overexpressed in solid tumors, including small cell lung cancer (SCLC). However, the molecular mechanism regulating MET stability and turnover in SCLC remains undefined. One potential mechanism of MET regulation involves the C-terminus of Hsp70-interacting protein (CHIP), which targets heat shock protein 90-interacting proteins for ubiquitination and proteasomal degradation. In the present study, we investigated the functional effects of CHIP expression on MET regulation and the control of SCLC cell apoptosis and invasion. METHODS: To evaluate the expression of CHIP and c-Met, which is a protein that in humans is encoded by the MET gene (the MET proto-oncogene), we examined the expression pattern of c-Met and CHIP in SCLC cell lines by western blotting. To investigate whether CHIP overexpression reduced cell proliferation and invasive activity in SCLC cell lines, we transfected cells with CHIP and performed a cell viability assay and cellular apoptosis assays. RESULTS: We found an inverse relationship between the expression of CHIP and MET in SCLC cell lines (n=5). CHIP destabilized the endogenous MET receptor in SCLC cell lines, indicating an essential role for CHIP in the regulation of MET degradation. In addition, CHIP inhibited MET-dependent pathways, and invasion, cell growth, and apoptosis were reduced by CHIP overexpression in SCLC cell lines. CONCLUSION: CHIP is capable of regulating SCLC cell apoptosis and invasion by inhibiting MET-mediated cytoskeletal and cell survival pathways in NCI-H69 cells. CHIP suppresses MET-dependent signaling, and regulates MET-mediated SCLC motility.
Apoptosis ; Blotting, Western ; Cell Line ; Cell Proliferation ; Cell Survival ; Heat-Shock Proteins ; Humans ; Lung Neoplasms ; Small Cell Lung Carcinoma* ; Ubiquitin ; Ubiquitination

OBJECTIVETo investigate the mechanism by which heat shock protein 90 (HSP90) regulates 26S proteasome in hyperthermia.

METHODSHyperthermic HepG2 cell models established by exposure of the cells to 42 degrees celsius; for 3, 6, 12, and 24 h were examined for production of reactive oxygen species (ROS) and cell proliferation, and the changes in Hsp90α and 26S proteasome were analyzed.

RESULTSROS production in the cells increased significantly after hyperthermia (F=28.958, P<0.001), and the cell proliferation was suppressed progressively as the heat exposure time extended (F=621.704, P<0.001). Hyperthermia up-regulated Hsp90α but decreased the expression level (F=164.174, P<0.001) and activity (F=133.043, P<0.001) of 26S proteasome. The cells transfected with a small interfering RNA targeting Hsp90α also showed significantly decreased expression of 26S proteasome (F=180.231, P<0.001).

CONCLUSIONThe intracellular ROS production increases as the hyperthermia time extends. Heat stress and ROS together cause protein denature, leading to increased HSP90 consumption and further to HSP90 deficiency for maintaining 26S proteasome assembly and stability. The accumulation of denatured protein causes unfolded protein reaction in the cells to eventually result in cell death.

HSP90 Heat-Shock Proteins ; metabolism ; Hep G2 Cells ; Hot Temperature ; Humans ; Proteasome Endopeptidase Complex ; metabolism ; RNA, Small Interfering ; genetics ; Reactive Oxygen Species ; metabolism ; Up-Regulation

OBJECTIVETo explore the change in the expression of extracellular heat shock protein 70 (eHSP70) and interleukin 2 (IL-2) and their correlation in intestine of rats with severe scald injury, and to observe the effects of eHSP70 on CD3(+) T lymphocytes in Peyer's patch of intestine in rats with severe scald injury in vitro.

METHODS(1) Sixty male SD rats were divided into normal control group (NC, n=10, only anesthetized) and scald group (S, n=50) according to the random number table. Rats in scald group were inflicted with 30% total body surface area full-thickness scald on the back. Ten rats from group NC immediately after anesthetization and 10 rats from group S at post injury hour (PIH) 3, 6, 12, 24, 48 were sacrificed to harvest their small intestines. The expressions of eHSP70 and IL-2 were determined with enzyme-linked immunosorbent assay (ELISA), and their correlation was analyzed. (2) Another 2 male SD rats were inflicted with the same injury as above. At PIH 12, CD3(+) T lymphocytes in Peyer's patch of small intestine were isolated and cultured with RPMI 1640 nutrient solution containing 10% fetal bovine serum. Cells were divided into blank control group (BC) and 5, 10, 20 μg/mL eHSP70 groups according to the random number table, with 6 wells in each group. Cells in group BC didn't receive any other treatment, while cells in the latter three groups were treated with corresponding mass concentration of recombinant rat eHSP70. After being cultured for 48 hours, the proportions of Th1 and Th2 in CD3(+) T lymphocytes, and the apoptosis rate of CD3(+) T lymphocytes were detected with flow cytometer, while the expressions of IL-2 and IL-10 in culture supernatant of cells were determined with ELISA. The cell experiments were repeated for 10 times. Data were processed with one-way analysis of variance, Kruskal-Wallis rank sum test, SNK-q test, and Pearson correlation analysis.

RESULTS(1) Compared with those in group NC [(1 278±135) and (48.6±4.9) ng/mg], the levels of eHSP70 [(728±93), (412±31), (314±21), (528±40), (1 028±97) ng/mg] and IL-2 [(38.6±2.3), (32.3±1.0), (25.3±3.6), (33.9±4.1), (44.3±2.6) ng/mg] in intestine of rats in group S obviously decreased at PIH 3, 6, 12, 24, 48 (with q values from 3.48 to 5.32, P values below 0.05), reaching the nadir both at PIH 12, with a significantly positive correlation between the level of IL-2 and the level of eHSP70 (r=0.920, P<0.01). (2) Compared with those in group BC [(8.6±1.1)% and (3.75±0.45)%], the proportion of Th1 obviously increased [(11.3±2.1)%, (15.7±1.8)%, (10.8±1.5)%, with q values from 2.97 to 4.57, P values below 0.05], while the proportion of Th2 obviously decreased [(2.39±0.38)%, (1.05±0.23)%, (2.67±0.26)%, with q values from 2.48 to 4.32, P values below 0.05] in CD3(+) T lymphocytes of rats in 5, 10, 20 μg/mL eHSP70 groups. Compared with those in group BC [(34.3±2.2)% and (254±16) pg/mL], the apoptosis rate of CD3(+) T lymphocytes obviously decreased [(26.1±2.6)%, (20.7±1.5)%, (31.5±2.4)%, with q values from 3.47 to 4.95, P values below 0.05], while the level of IL-2 obviously increased [(417±22), (587±19), (307±27) pg/mL, with q values from 3.02 to 4.98, P values below 0.05] in culture supernatant of CD3(+) T lymphocytes of rats in 5, 10, 20 μg/mL eHSP70 groups. There was no significant difference in the level of IL-10 in culture supernatant of CD3(+) T lymphocytes of rats among the four groups (F=2.12, P>0.05).

CONCLUSIONSThe expressions of eHSP70 and IL-2 in intestine of rats are decreased after severe scald, with a obviously positive correlation between them. eHSP70 can promote the differentiation of CD3(+) T lymphocytes in Th1 orientation, decrease the apoptosis rate of the cells, and promote the release of IL-2 of cells in Peyer's patch of intestine in rats with severe scald injury in vitro.

Animals ; Burns ; metabolism ; CD3 Complex ; metabolism ; Enzyme-Linked Immunosorbent Assay ; HSP70 Heat-Shock Proteins ; metabolism ; Interleukin-10 ; metabolism ; Interleukin-2 ; metabolism ; Intestine, Small ; metabolism ; Male ; Peyer's Patches ; metabolism ; Random Allocation ; Rats ; Rats, Sprague-Dawley ; Th1 Cells ; cytology

PURPOSE: Heat shock proteins (HSPs) are highly expressed during stress responses and cellular adaptation to environmental changes. One such protein is HSP27, a 27kDa protein that prevents cell death induced by many pro-apoptotic agents. Therefore, the aim of this study was to investigate the correlation between HSP27 expression and apoptosis induced by doxazosin treatment in prostate cancer cell line PC-3. MATERIALS AND METHODS: RT-PCR, Western blotting, and immunocytochemical staining were performed to determine whether HSP27 mRNA and protein are expressed in PC-3 cells. Next, to investigate the effects of doxazosin on apoptosis and HSP27 protein expression in PC-3 cells, the cells were stained using a TUNEL kit (to detect apoptotic cells) and with HSP27 antibody (to assess HSP27 protein expression) 6, 12, 24, and 48h after treatment with 25microM doxazosin. In addition, to determine whether HSP27 mRNA interference accelerates doxazosin-induced apoptosis of PC-3, we knocked down HSP27 with siRNA and then evaluated the rate of apoptosis after doxazosin treatment. RESULTS: HSP27 mRNA and protein were expressed in PC-3 cells. Furthermore, HSP27 mRNA and protein levels increased until 12 hours after 25microM doxazosin treatment, whereas the rate of apoptosis did not increased dramatically. After 12 hours, HSP27 expression decreased and then apoptosis was accelerated. In addition, siRNA-mediated knockdown of HSP27 induce higher apoptosis rate of PC-3 cells even before 12hrs after doxazosin treatment. CONCLUSIONS: By inhibiting apoptosis, HSP27 expression might play an important role in inhibiting progression to castration-refractory prostate cancer and resistance to anti-cancer treatment.
Apoptosis* ; Blotting, Western ; Cell Death ; Cell Line* ; Doxazosin ; Heat-Shock Proteins* ; Hot Temperature* ; HSP27 Heat-Shock Proteins* ; In Situ Nick-End Labeling ; Prostate* ; Prostatic Neoplasms* ; RNA, Messenger ; RNA, Small Interfering

PURPOSE: There are currently no consistently effective treatments for the excessive collagen produced by keloid fibroblasts. Previously, we reported that heat shock protein 70 (Hsp70) is up-regulated in keloid fibroblasts and keloid tissue. We, therefore, investigated whether Hsp70 is related to excessive collagen production in keloid fibroblasts. MATERIALS AND METHODS: We inhibited Hsp70 in keloid fibroblasts by RNA interference and examined the resulting collagen expression. Thus, we selected small interfering RNAs (siRNAs) specific for human Hsp70, transfected them into keloid fibroblasts, and evaluated the resulting phenotypes and protein production using real-time polymerase chain reaction (PCR), Western blot, and a collagen assay. RESULTS: The siRNAs dramatically suppressed Hsp70 mRNA expression, resulting in a decrease in collagen production in the keloid fibroblasts compared with controls. The siRNAs did not influence the viability of the keloid fibroblasts. CONCLUSION: Hsp70 overexpression likely plays an important role in the excessive collagen production by keloid fibroblasts. RNA interference has therapeutic potential for the treatment of keloids.
Adolescent ; Adult ; Blotting, Western ; Collagen/*drug effects/metabolism ; Female ; Fibroblasts/metabolism ; Gene Expression Regulation ; HSP70 Heat-Shock Proteins/genetics/metabolism/*pharmacology ; Humans ; Keloid/*drug therapy/genetics/metabolism ; Male ; RNA, Messenger/*genetics ; RNA, Small Interfering/*genetics ; Real-Time Polymerase Chain Reaction ; Transfection ; Up-Regulation

To screen molecular chaperones similar to small heat shock proteins (sHsps), but without alpha-crystalline domain, heat-stable proteins from Schizosaccharomyces pombe were analyzed by 2-dimensional electrophoresis and matrix assisted laser desorption/ionization time-of-flight mass spectrometry. Sixteen proteins were identified, and four recombinant proteins, including cofilin, NTF2, pyridoxin biosynthesis protein (Snz1) and Wos2 that has an alpha-crystalline domain, were purified. Among these proteins, only Snz1 showed the anti-aggregation activity against thermal denaturation of citrate synthase. However, pre-heating of NTF2 and Wos2 at 70degrees C for 30 min, efficiently prevented thermal aggregation of citrate synthase. These results indicate that Snz1 and NTF2 possess molecular chaperone activity similar to sHsps, even though there is no alpha-crystalline domain in their sequences.
alpha-Crystallins ; Citrate (si)-Synthase ; Electrophoresis ; Heat-Shock Proteins, Small* ; Mass Screening* ; Mass Spectrometry ; Molecular Chaperones* ; Pyridoxine ; Recombinant Proteins ; Schizosaccharomyces*

BACKGROUND/AIMS: Ethanol administration causes intestinal epithelial cell damage by increasing intestinal permeability and the translocation of endotoxins from intestinal bacterial flora. Heat shock proteins (HSPs) are associated with recovery and protection from cell damage. The aim of the current study was to investigate differences in the expression of HSPs in the small intestine and the biochemical changes attributable to ethanol-induced intestinal damage. METHODS: Ethanol (20%) was injected intraperitoneally (2.75 g/kg, 5.5 g/kg, 8.25 g/kg) in ICR mice and the same volume of saline was administered to controls. After 1 hour, the proximal, middle, and distal segments were taken from the small intestine and the degree of damage was analyzed. In each segment, the expression of HSPs was analyzed by western blotting. The expression of inflammatory mediators including interleukin-1beta (IL-1beta), tumor necrosis factor-alpha (TNF-alpha), cyclooxygenase-2 (COX-2), and antioxidant enzyme such as glutathione-S-transferase were compared using real-time polymerase chain reaction assays. RESULTS: In the control group, HSP70 increased in all segments of small intestine. Additionally, increases in the expression of HSP40 and HSP90 in the distal regions and an increase in HSP32 in the middle regions were observed. After ethanol treatment, greater histological damage was observed in the distal small intestine and significant decreases in HSPs were observed generally. Increased expression of IL-1beta, TNF-alpha, and COX-2 was observed in small intestinal tissues exposed to ethanol-induced damage. However, there was no significant difference in the expression of an antioxidant enzyme. CONCLUSIONS: Significant differences in the expression of HSPs in different intestinal regions were observed. These differences may have been attributable to the distribution of intestinal bacteria.
Animals ; Bacteria ; Blotting, Western ; Cyclooxygenase 2 ; Cytokines* ; Endotoxins ; Epithelial Cells ; Ethanol* ; Heat-Shock Proteins* ; Interleukin-1beta ; Intestine, Small* ; Mice ; Mice, Inbred ICR* ; Permeability ; Real-Time Polymerase Chain Reaction ; Tumor Necrosis Factor-alpha

OBJECTIVETo construct a single-chain human anti-EGFR antibody (scFv) and truncated protamine (tP) fusion protein, ScFv/tP, carrying small interfering (si)RNA directed against the heat shock protein Hsp47, a collagen-binding glycoprotein, in order to evaluate the role Hsp47 in apoptosis of hepatic stellate cells.

METHODSA single chain of the human variable fragment was obtained by phage display and fused with the tP gene and with or without (negative control) the Hsp47 siRNA sequences. Following expression and purification of the scFv/tP fusion protein and the scFv/tPHsp47 siRNA fusion protein, internalization capabilities were tested in isolated human hepatic stellate cells and the QSG-7701 human hepatocyte cells with visualization by immunofluorescent staining. The DNA binding ability of the fusion proteins were verified by gel shift assay.Following ScFv/tP-Hsp47 siRNA fusion protein transfection into the human hepatic stellate cells, the levels of Hsp47 mRNA and protein expression were tested by RT-PCR and Western blotting; in addition, effects of siRNA-mediated silencing of Hsp47 on cell proliferation and apoptosis were analyzed by the cell counting kit (CCK)-8, flow cytometry and Western blot detection of the apoptosis marker poly (ADP-ribose) polymerase (PARP).

RESULTSIndirect immunofluorescence revealed that the ScFv/tP fusion proteins were internalized into human hepatic stellate cells but not into the QSG-7701 cells.The ScFv/tP-Hsp47 siRNA fusion protein caused reduced expression of Hsp47 mRNA and protein expression in the human hepatic stellate cells, as well as increased the cells' apoptosis remarkably.

CONCLUSIONThe ScFv/tP fusion protein can be used as a transfection reagent to deliver Hsp47 siRNA into hepatic stellate cells and to mediate apoptosis via blockade of Hsp47 expression.

Apoptosis ; Cell Proliferation ; HSP47 Heat-Shock Proteins ; genetics ; Hepatic Stellate Cells ; cytology ; Humans ; Protamines ; metabolism ; RNA, Messenger ; RNA, Small Interfering ; Receptor, Epidermal Growth Factor ; immunology ; Single-Chain Antibodies ; Transfection