Insulin-like growth factor 2 targets IGF1R signaling transduction to facilitate metastasis and imatinib resistance in gastrointestinal stromal tumors

BACKGROUND Gastrointestinal stromal tumors(GISTs)are typical gastrointestinal tract neoplasms.Imatinib is the first-line therapy for GIST patients.Drug resistance limits the long-term effectiveness of imatinib.The regulatory effect of insulin-like growth factor 2(IGF2)has been confirmed in various cancers and is related to resistance to chemotherapy and a worse prognosis.AIM To further investigate the mechanism of IGF2 specific to GISTs.METHODS IGF2 was screened and analyzed using Gene Expression Omnibus(GEO:GSE225819)data.After IGF2 knockdown or overexpression by transfection,the phenotypes(proliferation,migration,invasion,apoptosis)of GIST cells were characterized by cell counting kit 8,Transwell,and flow cytometry assays.We used western blotting to evaluate pathway-associated and epithelial-mesenchymal transition(EMT)-associated proteins.We injected transfected cells into nude mice to establish a tumor xenograft model and observed the occurrence and metastasis of GIST.RESULTS Data from the GEO indicated that IGF2 expression is high in GISTs,associated with liver metastasis,and closely related to drug resistance.GIST cells with high expression of IGF2 had increased proliferation and migration,invasiveness and EMT.Knockdown of IGF2 significantly inhibited those activities.In addition,OEIGF2 promoted GIST metastasis in vivo in nude mice.IGF2 activated IGF1R signaling in GIST cells,and IGF2/IGF1R-mediated glycolysis was required for GIST with liver metastasis.GIST cells with IGF2 knockdown were sensitive to imatinib treatment when IGF2 overexpression significantly raised imatinib resistance.Moreover,2-deoxy-D-glucose(a glycolysis inhibitor)treatment reversed IGF2 overexpressionmediated imatinib resistance in GISTs.CONCLUSION IGF2 targeting of IGF1R signaling inhibited metastasis and decreased imatinib resistance by driving glycolysis in GISTs.

Relation of the IGF/IGF1R system to autophagy in colitis and colorectal cancer

Metabolic syndrome(Met S), as a chronic inflammatory disorder has a potential role in the development of inflammatory and cancerous complications of the colonic tissue. The interaction of DNA damage and inflammation is affected by the insulin-like growth factor 1 receptor(IGF1 R) signaling pathway. The IGF1 R pathway has been reported to regulate autophagy, as well, but sometimes through a bidirectional context. Targeting the IGF1 R-autophagy crosstalk could represent a promising strategy for the development of new antiinflammatory and anticancer therapies, and may help for subjects suffering from Met S who are at increased risk of colorectal cancer. However, therapeutic responses to targeted therapies are often shortlived, since a signaling crosstalk of IGF1 R with other receptor tyrosine kinases or autophagy exists, leading to acquired cellular resistance to therapy. From a pharmacological point of view, it is attractive to speculate that synergistic benefits could be achieved by inhibition of one of the key effectors of the IGF1 R pathway, in parallel with the pharmacological stimulation of the autophagy machinery, but cautiousness is also required, because pharmacologic IGF1 R modulation can initiate additional, sometimes unfavorable biologic effects.

不同碘营养大鼠血清胰岛素样生长因子I水平的研究

目的 研究不同碘营养状态下大鼠血清中胰岛素样生长因子 I(IGF1)的浓度及其与甲状腺素水平的相关性。方法 复制碘缺乏大鼠动物模型 ,给予不同的碘营养。分离大鼠血清 ,以自行建立的双位点夹心EL ISA检测 IGF1浓度 ,并同时测定血清甲状腺素的水平。结果 与正常大鼠相比较 ,碘缺乏大鼠血清 IGF1浓度明显降低 ,给予适量的碘补充后可使其恢复至正常水平。并且血清中 IGF1浓度与 T4的水平密切相关。结论 碘缺乏导致骨、脑发育障碍的部分原因可能是因为降低了血清中甲状腺素的水平 ,因此导致

血管内皮生长因子在多发性骨髓瘤骨髓组织中的表达及其意义

目的 :检测多发性骨髓瘤 (MM )骨髓活检塑料包埋切片中血管内皮生长因子 (VEGF)的表达情况 ,探讨VEGF在MM发病机制中的作用。方法 :对 2 0例初诊的MM患者和 10例正常对照者进行骨髓活检 ,制成塑料包埋切片 ,应用免疫组织化学SP染色法检测骨髓组织中VEGF表达情况和微血管密度 (MVD) ,进行分析研究。结果 :2 0例初诊MM患者骨髓中MVD及VEGF表达阳性率高于对照组 ,VEGF和MVD呈正相关。结论 :VEGF和MM的血管生成密切相关 ;VEGF在MM发病机制中起着重要作用 ;抑制VEGF的分泌将有可能成为一种新的治疗MM的有效方法。

Human umbilical cord mesenchymal stem cells attenuate diabetic nephropathy through the IGF1R-CHK2-p53 signalling axis in male rats with type 2 diabetes mellitus

diabetes mellitus(DM)is a disease syndrome characterized by chronic hyperglycaemia.A long-term high-glucose environment leads to reactive oxygen species(ROS)production and nuclear DNA damage.human umbilical cord mesenchymal stem cell(HUcMSC)infusion induces significant antidiabetic effects in type 2 diabetes mellitus(T2DM)rats.Insulin-like growth factor 1(IGF1)receptor(IGF1R)is important in promoting glucose metabolism in diabetes;however,the mechanism by which HUcMSC can treat diabetes through IGF1R and DNA damage repair remains unclear.In this study,a DM rat model was induced with high-fat diet feeding and streptozotocin(STZ)administration and rats were infused four times with HUcMSC.Blood glucose,interleukin-6(IL-6),IL-10,glomerular basement membrane,and renal function were examined.Proteins that interacted with IGF1R were determined through coimmunoprecipitation assays.The expression of IGF1R,phosphorylated checkpoint kinase 2(p-CHK2),and phosphorylated protein 53(p-p53)was examined using immunohistochemistry(IHC)and western blot analysis.Enzyme-linked immunosorbent assay(ELISA)was used to determine the serum levels of 8-hydroxydeoxyguanosine(8-OHdG).Flow cytometry experiments were used to detect the surface markers of HUcMSC.The identification of the morphology and phenotype of HUcMSC was performed by way of oil red“O”staining and Alizarin red staining.DM rats exhibited abnormal blood glucose and IL-6/10 levels and renal function changes in the glomerular basement membrane,increased the expression of IGF1 and IGF1R.IGF1R interacted with CHK2,and the expression of p-CHK2 was significantly decreased in IGF1R-knockdown cells.When cisplatin was used to induce DNA damage,the expression of p-CHK2 was higher than that in the IGF1R-knockdown group without cisplatin treatment.HUcMSC infusion ameliorated abnormalities and preserved kidney structure and function in DM rats.The expression of IGF1,IGF1R,p-CHK2,and p-p53,and the level of 8-OHdG in the DM group increased significantly compared with those in the control group,and decreased after HUcMSC treatment.Our results suggested that IGF1R could interact with CHK2 and mediate DNA damage.HUcMSC infusion protected against kidney injury in DM rats.The underlying mechanisms may include HUcMSC-mediated enhancement of diabetes treatment via the IGF1R-CHK2-p53 signalling pathway.

IGF-1R/β-catenin signaling axis is involved in type 2 diabetic osteoporosis

Insulin-like growth factor-1 receptor(IGF-1 R)is involved in both glucose and bone metabolism.IGF-1 R signaling regulates the canonical Wnt/β-catenin signaling pathway.In this study,we investigated whether the IGF-1 R/β-catenin signaling axis plays a role in the pathogenesis of diabetic osteoporosis(DOP).Serum from patients with or without DOP was collected to measure the IGF-1 R level using enzyme-linked immunosorbent assay(ELISA).Rats were given streptozotocin following a four-week high-fat diet induction(DOP group),or received vehicle after the same period of a normal diet(control group).Dual energy X-ray absorption,a biomechanics test,and hematoxylin-eosin(HE)staining were performed to evaluate bone mass,bone strength,and histomorphology,respectively,in vertebrae.Quantitative real-time polymerase chain reaction(qRT-PCR)and western blotting were performed to measure the total and phosphorylation levels of IGF-1 R,glycogen synthase kinase-3β(GSK-3β),andβ-catenin.The serum IGF-1 R level was much higher in patients with DOP than in controls.DOP rats exhibited strikingly reduced bone mass and attenuated compression strength of the vertebrae compared with the control group.HE staining showed that the histomorphology of DOP vertebrae was seriously impaired,which manifested as decreased and thinned trabeculae and increased lipid droplets within trabeculae.PCR analysis demonstrated that IGF-1 R mRNA expression was significantly up-regulated,and western blotting detection showed that phosphorylation levels of IGF-1 R,GSK-3β,andβ-catenin were enhanced in DOP rat vertebrae.Our results suggest that the IGF-1 R/β-catenin signaling axis plays a role in the pathogenesis of DOP.This may contribute to development of the underlying therapeutic target for DOP.

神经生长因子对大鼠脊髓损伤后神经元凋亡的影响

目的 探讨神经生长因子 (NGF)对脊髓损伤保护作用的分子机制。方法 采用Allen’s法以 2 5gcm力致伤大鼠T8脊髓 ,经蛛网膜下腔导管于术后即刻、2、4、8、12、2 4h各注入NGF溶液 ,并与生理盐水组 (NS组 )和正常对照组作对照 ,采用免疫组织化学方法和末端单位标记法 (TUNEL)原位末端标记法分别检测bcl 2、bax蛋白在脊髓神经元的表达及神经元凋亡情况。结果正常组中脊髓灰质bax蛋白阳性细胞吸光度 (A )值为 34 .5 1± 4.47,NS组中bax蛋白表达增加 ,以 2h及 12h最为显著 ,而NGF组与NS组相比 ,bax蛋白表达明显减少 ( P <0 .0 1)。正常组中脊髓灰质bcl 2蛋白表达的A值为 19.72± 2 .92 ,NS组中bcl 2表达下降 ,而NGF组与NS组相比较 ,bcl 2蛋白表达明显增多 (P <0 .0 1)。TUNEL检测结果显示 ,正常对照组中未见神经元凋亡 ,NS组中自 2h后可见神经元凋亡 ,NGF组与NS组相比 ,神经元凋亡指数明显减少 (P <0 .0 1)。结论 NGF能通过抑制bax蛋白的表达 ,促进bcl 2表达抑制脊髓损伤后神经元凋亡 ,从而保护损伤的脊髓组织 ,这可能是NGF对脊髓损伤具有保护作用的机制之一。