Study on relationship between IGFBP-5/p53 axis and anti-proliferation effect of tetrandrine in MCF-7 cells / 中国药理学通报

Aim To study the effect of tetrandrine ( Tet ) on proliferation of MCF-7 breast cancer cells and the possible mechanism underlying this biological process. Methods CCK-8, flow cytometric and Western blot were introduced to analyze the effect of Tet on proliferation and apoptosis in MCF-7 cells.Re-al-time PCR and/or Western blot assay were employed to detect the effect of Tet on expression of IGFBP-5 , p53 and MDM2.CCK-8 and recombinant adenovirus were utilized to determine the effect of IGFBP-5 on the proliferation inhibitory effect of Tet .Western blot assay was introduced to evaluate the effect of IGFBP-5 on p53 which was induced by Tet .Results Tet inhibited the proliferation , arrested cell cycle at G 1 phase and decreased the expression of PCNA concentration dependently in MCF-7 cells.Meanwhile, Tet increased the percentage of apoptotic cells , the level of Bad and reduced the level of Bcl-2.Tet increased the expres-sion of IGFBP-5 either mRNA or protein , over-expres-sion of IGFBP-5 enhanced the anti-proliferation activity of Tet in MCF-7 cells, but knockdown of IGFBP-5 at-tenuated this effect of Tet .Tet increased the level of p53 and decreased that of MDM2, and exogenous IG-FBP-5 enhanced the effect of Tet on p53 and MDM2, respectively .Conclusion Tet can inhibit the prolifer-ation of MCF-7 cells, and this activity is partly media-ted by increasing the function of p 53 signal , which may be triggered by the Tet-induced IGFBP-5.

Study on the relationship between Insulin-like growth factor binding protein 5 and anti-proliferating effect of tetrandrine on human colon cancer cells / 中国药理学通报

Aim To investigate the anti-proliferating effect of tetrandrine ( Tet ) on colon cancer cells and its possible molecular mechanism. Methods We intro-duced crystal violet staining and flow cytometry to ana-lyze the effect of Tet on proliferation in LoVo cells. Flow cytometry was used to detect the effect of Tet on apoptosis in LoVo cells. Western blot assay was taken to analyze the effect of Tet on the expression of insulin-like growth factor binding protein 5 ( IGFBP5 ) . Final-ly, luciferase reporter assay, recombinant adenovirus mediated over-expression or silence of IGFBP5 were used to analyze the possible role of IGFBP5 in the anti-proliferating effect of Tet on colon cancer cells. Re-sults Crystal violet staining and flow cytometery anal-ysis results showed that Tet could exert an anti-prolifer-ating effect and induce apoptosis in LoVo cells. Tet de-creased the expression of IGFBP5 in a concentration-dependent manner. Tet inhibited the transcriptional ac-tivity of pTOP-luc reporter, which could be reversed by exogenous expression of IGFBP5 mostly. Similar results were found in the expression of c-Myc, but IGFPB5 knockdown couldn’ t reverse this effect. Conclusion Tet can inhibit the proliferation of colon cancer cells, and this effect may be mediated by down-regulating the expression of IGFBP5 to inhibit Wnt/β-catenin signa-ling transduction partly.

Relationship between cisplatin resistance of primary lung cancer and expression levels of ERCC1 and IGFBP5 in patient-derived tumor xenograft models / 中国肿瘤临床

Objective:To establish a lung cancer model of patient-derived tumor xenografts (PDTX) and to explore the relation-ship between primary cisplatin resistance and ERCC1 and IGFBP5 expression levels. Methods:Lung cancer tissues from 84 patients who underwent surgery were collected and implanted into nude mice. Patient characteristics for the first generation xenografts that were and were not engrafted were compared. Passage 3 xenografts were treated with cisplatin. The expression levels of ERCC1 and IGFBP5 in cisplatin-resistant and cisplatin-sensitive groups were detected using immunohistochemistry assay. Results:The model success rates were 32.14%(27/84) in first-generation xenografts, 88.89%(24/27) in second-generation xenografts, and 95.83%(23/24) in third-gener-ation xenografts. The tumorigenicity of first-generation xenografts was correlated with size, differentiation, clinical stage, and histologi-cal type. PDTX tumors maintain the histological type of parental tumors through serial passage in nude mice. ERCC1 expression level was significantly higher in the cisplatin-resistant group than in the cisplatin-sensitive group, whereas the IGFBP5 expression level was lower in the cisplatin-resistant group than in the cisplatin-sensitive group. Conclusion:Lung cancer PDTX models were successfully es-tablished, and histological characteristics of the primary cancers were retained. Therefore, the models may serve a function in preclini-cal research of lung tumor biology and for exploring the drug resistance mechanism of tumors. The cisplatin resistance of primary lung cancer may be correlated with the expression level of ERCC1 and IGFBP5 in lung carcinoma.

Pitavastatin Regulates Ang II Induced Proliferation and Migration via IGFBP-5 in VSMC

Angiotensin II (Ang II), a key mediator of hypertensive, causes structural changes in the arteries (vascular remodeling), which involve alterations in cell growth, vascular smooth muscle cell (VSMC) hypertrophy. Ang II promotes fibrotic factor like IGFBP5, which mediates the profibrotic effects of Ang II in the heart and kidneys, lung and so on. The purpose of this study was to identify the signaling pathway of IGFBP5 on cell proliferation and migration of Ang II-stimulated VSMC. We have been interested in Ang II-induced IGFBP5 and were curious to determine whether a Pitavastatin would ameliorate the effects. Herein, we investigated the question of whether Ang II induced the levels of IGFBP5 protein followed by proliferation and migration in VSMC. Pretreatment with the specific Angiotensin receptor type 1 (AT1) inhibitor (Losartan), Angiotensin receptor type 2 (AT2) inhibitor (PD123319), MAPK inhibitor (U0126), ERK1/2 inhibitor (PD98059), P38 inhibitor (SB600125) and PI3K inhibitor (LY294002) resulted in significantly inhibited IGFBP5 production, proliferation, and migration in Ang II-stimulated VSMC. In addition, IGFBP5 knockdown resulted in modulation of Ang II induced proliferation and migration via IGFBP5 induction. In addition, Pitavastatin modulated Ang II induced proliferation and migration in VSMC. Taken together, our results indicated that Ang II induces IGFBP5 through AT1, ERK1/2, P38, and PI3K signaling pathways, which were inhibited by Pitavastatin. These findings may suggest that Pitavastatin has an effect on vascular disease including hypertension.

Expression and clinical significance of insulin-like growth factor binding protein 5 in gastric adenocarcinoma / 中国肿瘤临床

Objective: To investigate the expression and prognostic significance of insulin-like growth factor binding protein 5 (IGFBP5) in gastric adenocarcinoma (GAC). Methods:IGFBP5 expression in tissue samples from 236 GAC patients was analyzed us-ing immunohistochemical methods. These patients had undergone surgical resection between 20003 and 2006 in Sun Yat-Sen Universi-ty Cancer Center. The relationship between IGFBP5 expression and clinicopathological factors in the 236 GAC patients was analyzed using Pearson correlation analysis. The significance of IGFBP5 in predicting the survival status of these patients was analyzed using Ka-plan-Meier survival analysis and Cox's proportional hazards regression model. Results:Immunohistochemical staining data indicated that IGFBP5 expression was significantly decreased in 159 of the total GAC cases (67.4%). Of the 62 cases with well-and moderately differentiated GAC, 31 (50%) exhibited reduced IGFBP5 expression. Of the 174 cases with poorly differentiated GAC, 128 showed re-duced IGFBP5 expression. Reduced IGFBP5 expression was also observed in female patients and in patients with tumors over 5 cm in size or with poorly differentiated tumors (P<0.05). The reduced expression of IGFBP5 was common in the tumors that were staged as T3+4a/b andⅢ/Ⅳ(P<0.05). Kaplan-Meier survival analysis revealed that the reduced expression of IGFBP5 was associated with poor prognosis in GAC patients (P<0.001). Cox regression analysis identified IGFBP5 expression as an independent prognostic factor for the overall survival of these cancer patients (HR=1.897, P=0.029). Conclusion: IGFBP5 expression is reduced in GAC tissues, and IGFBP5 independently predicts an unfavorable prognosis in GAC patients.

Insulin Like Growth Factor Binding Protein-5 Regulates Excessive Vascular Smooth Muscle Cell Proliferation in Spontaneously Hypertensive Rats via ERK 1/2 Phosphorylation

Insulin-like growth factor binding proteins (IGFBPs) are important components of insulin growth factor (IGF) signaling pathways. One of the binding proteins, IGFBP-5, enhances the actions of IGF-1, which include the enhanced proliferation of smooth muscle cells. In the present study, we examined the expression and the biological effects of IGFBP-5 in vascular smooth muscle cells (VSMCs) from spontaneously hypertensive rats (SHR) and Wistar Kyoto rats (WKY). The levels of IGFBP-5 mRNA and protein were found to be higher in the VSMC from SHR than in those from WKY. Treatment with recombinant IGFBP-5-stimulated VSMC proliferation in WKY to the levels observed in SHR. In the VSMCs of WKY, incubation with angiotensin (Ang) II or IGF-1 dose dependently increased IGFBP-5 protein levels. Transfection with IGFBP-5 siRNA reduced VSMC proliferation in SHR to the levels exhibited in WKY. In addition, recombinant IGFBP-5 significantly up-regulated ERK1/2 phosphorylation in the VSMCs of WKY as much as those of SHR. Concurrent treatment with the MEK1/2 inhibitors, PD98059 or U0126 completely inhibited recombinant IGFBP-5-induced VSMC proliferation in WKY, while concurrent treatment with the phosphatidylinositol-3 kinase inhibitor, LY294002, had no effect. Furthermore, knockdown with IGFBP-5 siRNA inhibited ERK1/2 phosphorylation in VSMC of SHR. These results suggest that IGFBP-5 plays a role in the regulation of VSMC proliferation via ERK1/2 MAPK signaling in hypertensive rats.

Alterations of Insulin-like Growth Factor-I mRNA and IGF Binding Protein-5 mRNA Expression Following Hypoxic-Ischemic Brain Injury in Immature Rat / 대한소아내분비학회지

PURPOSE:Insulin-like growth factor-I(IGF-I) is an essential anabolic factor for postnatal rat brain development and IGF-I expression is highly abundant during the first 21 days, critical growth period. Hypoxic-ischemic brain insults occurring during the perinatal period result in neuronal necrosis and permanent brain damage. To investigate the regulation of the action of IGF-I in response to such a hypoxic insult, we examined the gene expression of IGF-I and IGFBP-5 during the first 72 hr after hypoxic-ischemic injury in immature rat brain. METHODS:Ligation of the right carotid artery of 7-day-old rats was followed by 2 hour exposure to 8% oxygen to produce severe hypoxic brain damage. Using reverse transcriptase-polymerase chain reaction(RT-PCR), the expression of IGF-I mRNA and IGFBP-5 mRNA was determined in both hypoxic and control brains at post 1, 4, 12, 24, 48 hr and 72 hr after hypoxic-ischemic insult. RESULTS:The IGF-I mRNA and IGFBP-5 mRNA expression of hypoxic brain were not different from those of controls at 1 hr of recovery but IGF-I mRNA expression was decreased rapidly at post 4 hr, this decrease more pronounced at 12 hr of recovery. IGF-I mRNA and IGFBP-5 mRNA expression were increased at 48 hr and 24 hr of recovery, respectively and both IGF-I mRNA and IGFBP-5 mRNA expression showed similar level of controls at 72 hr of recovery. CONCLUSION: Out findings suggest that IGF-I play a important role in both neuronal loss and repair process following hypoxic-ischemic brain injury and IGFBP-5 is also strongly involved in the repair of damaged brain tissue by mediating IGF-I action. (J Korean Soc Pediatr Endocrinol 2003;8:56-63)