Retraction: ASIC1a involves acidic microenvironment-induced activation and autophagy of pancreatic stellate cells.

[This retracts the article DOI: 10.1039/C8RA03679A.].

Retracted Article: ASIC1a involves acidic microenvironment-induced activation and autophagy of pancreatic stellate cells.

Acid-sensing ion channel 1a (ASIC1a), as a member of the proton-gated cation channel family, can be activated by low extracellular pH, and takes part in many acidity-associated physiopathological processes. However, whether ASIC1a is expressed in human pancreatic stellate cells (PSCs) and involved in acid-induced physiopathological events has not been reported yet. In this study, we investigated the expression of ASIC1a in PSCs and its possible role in the activation and autophagy of PSCs evoked by extracellular acid. Our results show that ASIC1a is present in PSCs, and an enhanced expression of ASIC1a occurs under acid stimuli. More importantly, the activation and autophagy of PSCs can be induced in acidic medium, and inhibition of ASIC1a by ASIC1a-specific blocker psalmotoxin-1 (PcTx1) or siRNA knockdown could suppress these two acid-associated processes. Collectively, our present study reports for the first time that ASIC1a is expressed in PSCs, and provides evidence for the involvement of ASIC1a in the acidic microenvironment-induced activation and autophagy of PSCs.

[Protein and mRNA expression of CTGF, CYR61, VEGF-C and VEGFR-2 in bone marrow of leukemia patients and its correlation with clinical features].

This study was aimed to investigate the mRNA and protein expression of CTGF, CYR61, VEGF-C and VEGFR-2 in bone marrow of patients with leukemia, and to analyze the role and clinical significance of these 4 factors in genesis and development of leukemia, infiltration and metastasis of leukemic cells. A total of 100 cases of newly diagnosed leukemia, 26 cases of acute leukemia in complete remission and 30 controls were enrolled in this study. The mononuclear cells of bone marrow were collected, the mRNA and protein expression levels of CTGF, CYR61, VEGF-C, VEGFR-2 in leukemia patients and controls were detected by real time PCR and Western blot, respectively. The results showed that the mRNA and protein expression levels of above mentioned 4 factors were significantly higher than those in control (P < 0.05), only CTGF mRNA expression in AL patients after complete remission showed statistical difference as compared with control (P < 0.05), but the expression of CTGF mRNA showed statistical significance in different bone marrow hyperplasia of acute leukemia (P < 0.05). The expression level of CTGF protein showed difference in different chromosome karyotypes of leukemia (P < 0.05). The expression levels of CYR61 and VEGF-C proteins showed statistical difference in different bone marrow hyperplasia of acute leukemia (P < 0.05). The expression level of CTGF, CYR61, VEGF-C mRNA and protein in CML group were higher than that in control group. The expression levels of CTGF and CYR61 protein were higher than that in control. The mRNA and protein expression levels of above-mentioned 4 factors in sex and infiltration lf leukemic cells did not show statistical significance(P < 0.05). In correlative analysis, the mRNA expressions of above mentioned 4 factors were positively correlated with bone marrow blast count(P < 0.05), the protein expression of CTGF, CYR61 and VEGF-C were positively correlated with bone marrow blast count. It is concluded that the CTGF, CYR61, VEGF-C and VEGFR-2 mRNA and protein play a role in acute leukemia. In acute leukemia (AML/ALL), the expression of above mentioned factor was high, but except VEGFR-2. Most of them were positively correlated with bone marrow blast count. Joint block of these angiogenesis-related factors is likely to play an important role in targeting treatment of leukemia.

[Expression of CYR61, CTGF, VEGF-C, VEGFR-2 mRNA in bone marrow of leukemia patients and its clinical significance].

The study was aimed to detect the levels of CYR61, CTGF, VEGF-C, VEGFR-2 mRNA in bone marrow (BM) of leukemia patients and investigate the interaction of CYR61, CTGF, VEGF-C, VEGFR-2 proteins in occurrence, development, infiltration and metastasis of leukemia and its clinical significance, to find a new tumor marker for diagnosis and treatment of leukemia with some new directions. 74 patients with leukemia were enrolled in this study, 38 out of them were males and 36 were females, aged from 6 to 77 years old with the median age of 45 years old. In the control group, 7 males and 5 females, aged from 16 to 78 years old with the median age of 46. Semi-quantitative reverse transcription polymerase chain reaction (RT-PCR) was used to detect the levels of CYR61, CTGF, VEGF-C, VEGFR-2 mRNA. The results showed that the levels of CYR61, CTGF, VEGF-C, VEGFR-2 mRNA in BM of newly diagnosed patients with acute and chronic leukemia of each group were significantly higher as compared with the control group (p < 0.05). The levels of CYR61, CTGF mRNA in acute leukemia remission group were significantly higher than those in control group (p = 0.039, 0.025). The level of CTGF mRNA was highest in B-ALL group, and was higher than that in AML, CML, CLL, T-ALL groups (p = 0.002, 0.034, 0.002, 0.010). In AML group, mRNA expressions of CYR61 and CTGF, CYR61 and VEGF-C, CTGF and VEGFR-2 were positively correlated (r = 0.452, 0.466, 0.464; p = 0.045, 0.038, 0.039), and in CML group mRNA expression of CYR61 and VEGF-C was positively correlated (r = 0.882, p = 0.000). The expression levels of VEGF-C, VEGFR-2 mRNA in acute leukemia patients with extramedullary infiltration were higher than those in acute leukemia patients without extramedullary infiltration (p = 0.028, 0.047). VEGF-C mRNA expression and the original cell counts in AML group were positively correlated (r = 0.418, p = 0.034). It is concluded that CYR61, CTGF, VEGF-C and VEGFR-2 interact each other in the pathogenesis of leukemia, promote the development, metastasis and infiltration of leukemia; and these factors in different types of leukemia and extramedullary infiltration are different, which may become tumor markers of leukemia; and blocking VEGF-C and VEGFR-2 may block tumor growth and metastasis.

[Expression of cyclooxygenase-2 in bone marrow cells of leukemia patients and its association with angiogenesis].

The objective of this study was to investigate the effect of cyclooxygenase-2 (COX-2) in the angiogenesis of bone marrow in leukemia patients. 51 patients with newly diagnosed acute leukemia were taken as study objects, 18 healthy volunteers were enrolled in the control group. Bone marrow microvessel density (MVD) in bone marrow biopsy tissue section was determined with immunohistochemistry method, the vascular endothelial growth factor level in serum was detected with ELISA method and the expression of cyclooxygenase-2 in bone marrow cells was assayed by flow cytometry. The results showed that the MVD, VEGF level, positive rate of COX-2 expression in leukemia group all obviously increased as compared with the control group (p < 0.05). The correlative coefficients of MVD, VEGF level and COX-2 expression rate were 0.614, 0.423 and 0.577 respectively (p < 0.05). In conclusion, as well as solid tumors, leukemia may be also a angiogenesis-dependent malignant tumor. Coordination of COX-2 with VEGF may promote angiogenesis in bone marrow.

Neuroprotection of insulin against oxidative stress-induced apoptosis in cultured retinal neurons: involvement of phosphoinositide 3-kinase/Akt signal pathway.

In order to investigate the neuroprotection of insulin in retinal neurons, we used retinal neuronal culture as a model system to study the protective effects of insulin against H2O2-induced cytotoxicity and apoptotic death. Primary retinal neuronal cultures were grown from retinas of 0-2-day old Sprague-Dawley rats. Cell viability was measured by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide assay. Apoptotic cell death was evaluated by the TdT-mediated digoxigenin-dUTP nick-end labeling assay, and by DNA laddering analysis. Phosphoinositide 3-kinase (PI3K) activity was measured using phosphoinositide 4,5-bisphophate and [gamma-32P]ATP as substrate. Western blot analysis with anti-phospho-Akt (pS473) antibody was performed to examine the level of phosphorylated Akt. We observed that treatment with 100 microM H2O2 for 24 h significantly decreased cell viability and induced apoptotic death of retinal neurons, and that pretreatment with 10 nM insulin significantly inhibited or attenuated H2O2-induced cytotoxicity and apoptosis. Pretreatment with LY294002, a specific PI3K inhibitor, abolished the cytoprotective effect of insulin. Insulin also strongly activated both PI3K and the downstream effector Akt. These results suggest that insulin protects retinal neurons from oxidative stress-induced apoptosis and that the PI3K/Akt signal pathway is involved in insulin-mediated retinal neuroprotection.