Insulin-like growth factor II in the pathogenesis of human neuroblastoma.

Insulin-like growth factor II (IGF-II) acts as an autocrine growth factor for many in vitro tumor cell lines including neuroblastoma. To examine the role of IGF-II in tumor biology we have analyzed a total of 56 primary neuroblastoma tumor samples for the presence of IGF-II using a combination of mRNA and protein analysis. A group of 21 samples was examined for the presence of IGF-II mRNA by slot blot and a separate group of 37 samples was examined for IGF-II immunoreactivity. IGF-II was detected in 48% of the total tumor specimens analyzed. IGF-II immunoreactivity was observed in cells resembling developing neuroblasts and was confined to the cytoplasm and proximal neurites. The appearance of IGF-II mRNA and protein did not correlate with tumor prognostic features including stage, histology, or N-myc amplification. These data suggest that the expression of IGF-II is not confined to a specific stage of the disease but may have a broader role in the pathogenesis of neuroblastoma.     

Insulin-like growth factor II in gynecological cancers: a preliminary study

PROBLEM: We have previously reported elevated serum levels of cervical human papilloma viral proteins E6 and E7 and serum insulin-like growth factor II (IGF-II) in women with cervical cancer and advanced cervical intraepithelial neoplasia. As most women with cervical cancer have elevated levels of serum IGF-II, we sought to determine whether the cervical cancer and lymph node biopsies from these women demonstrated increased production of IGF-II and whether this elevation was also present in ovarian and endometrial cancers. METHOD OF STUDY: We used the semi-quantitative immunofluorescent antibody assay established in our laboratory to identify the levels of IGF-II in 21 cervical cancers (seven with matching lymph nodes), 18 benign cervical biopsies, 13 endometrial cancers, 15 benign endometrial biopsies, 5 ovarian cancers, and 15 benign ovarian biopsies. RESULTS: The immunofluorescent IGF-II levels (relative intensity per pixel) were the highest in cervical cancers; they were significantly higher than in matched controls. IGF-II levels were not higher in ovarian cancers and only slightly elevated in endometrial cancers. The presence of IGF-II in pelvic lymph nodes of women with cervical cancer paralleled with those in the cervical cancers. Interestingly, we could identify small nests of metastases of malignant cells in the nodes (pauci-cellular metastasis) by using IGF-II as the marker. CONCLUSION: We propose that measurement and identification of IGF-II in the cervical biopsy may be a sensitive method of detecting cervical cancer and metastatic spread in the lymph nodes.     

Insulin-like growth factor II acts through an endogenous growth pathway regulated by imprinting in early mouse embryos.

We present evidence that insulin-like growth factor II (IGF-II) mediates growth in early mouse embryos and forms a pathway in which imprinted genes influence development during preimplantation stages. mRNA and protein for IGF-II were expressed in preimplantation mouse embryos, but the related factors IGF-I and insulin were not. IGF-I and insulin receptors and the IGF-II/mannose-6-phosphate receptor were expressed. Exogenous IGF-II or IGF-I increased the cell number in cultured blastocysts, but a mutant form of IGF-II that strongly binds only the IGF-II receptor did not. Reduction of IGF-II expression by antisense IGF-II oligonucleotides decreased the rate of progression to the blastocyst stage and decreased the cell number in blastocysts. Preimplantation parthenogenetic mouse embryos expressed mRNA for the IGF-II receptor but not for either IGF-II ligand or the IGF-I receptor, indicating that the latter genes are not expressed when inherited maternally. These data imply that some growth factors and receptors, regulated by genomic imprinting, may control cell proliferation from the earliest stages of embryonic development.     

Insulin-like growth factor II prevents apoptosis in a human teratoma derived cell line

Aim—To study how insulin-like growth factor II (IGF-II) affects the behaviour of human teratoma cells.     

Insulin-like growth factor binding protein-1 and ovarian stimulation.

Serum concentrations of insulin-like growth factor binding protein-1 (IGFBP-1) were measured in 42 patients with tubal infertility undergoing two different regimens of ovarian stimulation for in-vitro fertilization. The first group comprised 24 women given a luteinizing hormone-releasing hormone agonist analogue (buserelin, LHRHa) on cycle days 1-4 followed by follicle-stimulating hormone and human menopausal gonadotrophin (LHRHa group). The second group of 18 women received clomiphene citrate and gonadotrophins (CC group). On the day of human chorionic gonadotrophin administration, the sum of follicular diameters (P less than 0.05) and the number of follicles punctured in the LHRHa group (P less than 0.01) were significantly higher than in the CC group. In spite of the greater number of follicles, the oestrogen levels were similar in both groups, but women in the LHRHa group had significantly higher serum IGFBP-1 concentrations during the last 5 days of stimulation. These results suggest that the stimulated preovulatory follicles may contribute to the elevation of serum IGFBP-1.     

Insulin-like growth factor (IGF) and bone

Bone is not only a rich source of a diverse group of growth factors, but is also a very responsive tissue to such growth promoting agents. IGF-I and IGF-II are reported to be synthesized and retained in bone. While both IGF-I and IGF-II stimulate DNA, collagen, and noncollagenous protein synthesis in cultured calvariae, these explant cultures have quantitative differential sensitivities to these IGF's. In addition to the observed increase in collagen synthesis, collagen degradation decreased in calvariae treated with IGF-I or IGF-II.     

Insulin-like growth factor II mediates resveratrol stimulatory effect on cathepsin D in breast cancer cells

Cathepsin D (CD) is an enzyme that promotes breast cancer. CD is stored intracellularly; however, we demonstrated that IGF-II promotes CD secretion in estrogen receptor positive (ER+) breast cancer cells. We also showed that resveratrol (RSV) stimulates IGF-II in ER(+) breast cancer cells. Thus, we designed this study to determine whether RSV regulates CD in MCF-7, T47D (ER+) breast cancer cells as well as in Hs578t (cancer) and MCF-10A (normal) ER ? cell lines. RSV (10^{? 6} M) increased CD and IGF-II secretion in ER+ but not ER ? cells. RSV treatment (10^{? 4} M) inhibited CD in ER+ but not in ER ? cells. Transfection of ER ? cells with proIGF-II increased CD secretion. RSV (10^{? 6} M) modulates CD secretion through IGF-II while RSV (10^{? 4} M) inhibits CD in ER+ but not ER ? cells. Regulation of CD by RSV represents a novel mechanism by which RSV may protect against breast cancer.     

Insulin-like growth factor II mediates resveratrol stimulatory effect on cathepsin D in breast cancer cells

Cathepsin D (CD) is an enzyme that promotes breast cancer. CD is stored intracellularly; however, we demonstrated that IGF-II promotes CD secretion in estrogen receptor positive (ER+) breast cancer cells. We also showed that resveratrol (RSV) stimulates IGF-II in ER(+) breast cancer cells. Thus, we designed this study to determine whether RSV regulates CD in MCF-7, T47D (ER+) breast cancer cells as well as in Hs578t (cancer) and MCF-10A (normal) ER - cell lines. RSV (10(- 6) M) increased CD and IGF-II secretion in ER+ but not ER - cells. RSV treatment (10(- 4) M) inhibited CD in ER+ but not in ER - cells. Transfection of ER - cells with proIGF-II increased CD secretion. RSV (10(- 6) M) modulates CD secretion through IGF-II while RSV (10(- 4) M) inhibits CD in ER+ but not ER - cells. Regulation of CD by RSV represents a novel mechanism by which RSV may protect against breast cancer.     

Insulin-like growth factor and the etiology of autism

The basic hypothesis for this study is that reduced peripartum level of insulin-like growth factor-1 (IGF) due to genetic, epigenetic, or environmental factors is a sentinel biomarker of increased probability of later development of autism. The central objective of the resultant proposed study described here is examining if a correlation exists between the serum level of IGF in the fetus/newborn and the probability of autism developing later in the child. Mechanisms possibly causing such a decrease are considered. This would define a prospective biomarker for and possible etiology of this disorder.     

Insulin-like growth factor system and sporadic malignant melanoma

Insulin and insulin-like growth factors (IGFs) are important regulators of energy metabolism and growth. Several findings have outlined an important role played by this family of molecules in both tumor maintenance and development. Despite the established contribution of the IGF system in carcinogenesis, little and contrasting data have been reported concerning the intertwined relationships between melanoma and this family of molecules. The present minireview aims to summarize the main topics and evidence concerning this malignant skin cancer, with a focus on the following: i) melanoma and cell proliferation effects induced by the IGF system, ii) in vitro and in vivo experimental data, and iii) targeting studies. Because of consistent findings regarding the role of the IGF-1 receptor in the modulation of IGF-1 activity, possible therapeutic strategies combining the use of antisense oligonucleotides against IGF-1 receptor mRNA could be applied in the future.     

Caveolin-3 is a sensitive and specific marker for rhabdomyosarcoma.

Caveolin-3 (Cav-3) is a principal structural protein of caveolae membrane domains. Animal studies have revealed that Cav-3 is expressed in skeletal and cardiac myocytes but absent in other types of cells. Recent studies have shown that abnormalities in the Cav-3 gene are associated with some forms of muscular dystrophy, while skeletal muscle abnormalities have been observed in Cav-3 transgenic and knockout mice. In this study the authors evaluated the distribution of Cav-3 in normal human tissues and compared the expression of Cav-3 with that of myogenin and myoD1 in rhabdomyosarcoma (RMS), malignant mixed mullerian tumor (MMMT), and an array of neoplasms that mimic RMS to assess the utility of Cav-3 as a diagnostic marker for tumors with skeletal muscle differentiation. In nonneoplastic human tissues, crisp membrane staining for Cav-3 was present in cardiac and skeletal myocytes and occasionally in arterial smooth muscle cells and prostatic stromal cells, while other cell types were negative for Cav-3. Eighty-eight percent (21/24) of RMS studied were positive for Cav-3. Positive staining was generally observed in the more maturely differentiated tumor cells but not the primitive tumor cells. Eight of nine cases of MMMT stained strongly with Cav-3 in their rhabdomyosarcomatous component but not in other components. Fifty-four other neoplasms (13 leiomyosarcomas, 8 neuroblastomas, 5 lymphomas, 6 Wilms tumors without skeletal muscle differentiation, 5 Ewing sarcomas, 4 malignant fibrous histiocytomas, 4 angiosarcomas, 6 malignant melanomas, and 3 synovial sarcomas) were negative for Cav-3 expression. Nearly all (96% [23/24]) cases of RMS were positive for myogenin, while 88% (21/24) were positive for myoD1. Primitive tumor cells showed significantly increased expression of myoD1 and myogenin; conversely, more differentiated tumor cells were negative or weakly stained. The rhabdomyosarcomatous component of MMMT stained focally with myogenin and myoD1, in contrast to the strong Cav-3 labeling in these cells. These results demonstrate that Cav-3 is specifically expressed in human cardiac and skeletal myocytes. Furthermore, its high specificity and relatively high sensitivity (88%) for tumors with skeletal muscle differentiation suggest that Cav-3 is a valuable marker for these tumors and may be used to assess the degree of differentiation of RMS and to identify residual tumor cells in post-chemotherapy specimens.     

Co-localisation of insulin-like growth factor II and the proliferation marker MIB1 in hepatocellular carcinoma cells.

AIM: To assess the effect of insulin-like growth factor II (IGF-II) on proliferation of hepatocellular carcinoma (HCC) cells. METHODS: Expression of IGF-II mRNA and protein was detected in 10 archival HCC specimens using in situ hybridisation and immunohistochemistry, respectively. Expression of the Ki-67 antigen, a proliferation marker, was determined immunohistochemically on the same sections. RESULTS: Increased expression of IGF-II mRNA and protein was detected in five of the 10 HCCs in cells located at the periphery of tumour nests. The pattern of localisation of IGF-II was almost identical with that of Ki-67 antigen. CONCLUSIONS: Most of the Ki-67 antigen positive cells co-expressed IGF-II, suggesting that IGF-II may act as an autocrine or paracrine growth factor, and may play an important role in the development of HCC.     

Insulin-like growth factor II mRNA-binding protein 3 (IMP3) expression in hepatocellular carcinoma. A clinicopathological analysis with emphasis on diagnostic value

Wachter D L, Kristiansen G, Soll C, Hellerbrand C, Breuhahn K, Fritzsche F, Agaimy A, Hartmann A & Riener M‐O
(2012) Histopathology  60, 278–286
Insulin‐like growth factor II mRNA‐binding protein 3 (IMP3) expression in hepatocellular carcinoma. A clinicopathological analysis with emphasis on diagnostic value Aims: Patients with hepatocellular carcinoma (HCC) usually present with advanced disease and rarely qualify for curative therapy. Immunohistochemical markers that help to discriminate benign from malignant processes early, and that have prognostic significance, would be useful. Expression of the oncofetal protein insulin‐like growth factor II mRNA‐binding protein 3 (IMP3) in malignant cells of different tumour types correlates with reduced overall survival. Methods and results: Tissue microarrays (TMAs) containing 55 normal liver samples, 365 HCCs (122 with corresponding non‐tumorous liver), 10 hepatocellular adenomas, 13 focal nodular hyperplasias and nine dysplastic nodules from western European patients were stained for IMP3. IMP3 was analysed in 61 core needle biopsies and findings were compared to glypican‐3 and CD34. HCCs in TMAs were strongly positive for IMP3 in 18.4% of cases compared to absent expression in normal and non‐tumorous liver tissue and benign liver tumours. Patients with IMP3 expression in HCCs showed significantly poorer overall survival in multivariate analysis (P = 0.044). Of the 61 core needle biopsies analysed, 32 (52.5%) of the HCCs were IMP3‐positive. Conclusions: In core needle biopsies, IMP3 expression seems to be of limited use as a single marker for the diagnosis of HCC, given a sensitivity of 52%, but it may be helpful in combination with other markers.     

胰岛素样生长因子1与神经干细胞源性神经元轴突的生长发育*

背景：研究表明胰岛素样生长因子1具有神经保护作用并能增加神经干细胞向神经元及少突胶质细胞分化的比例。 目的：观察胰岛素样生长因子1对神经干细胞源性神经元轴突生长发育的影响。 方法：分离培养新生Wistar大鼠海马神经干细胞,传3~5代后接种于24孔培养板。其中12孔加入10 μL胰岛素样生长因子1(500 mg/L)作为实验组,余为对照组。 结果与结论：培养1,2,3,4 d时,实验组细胞死亡数较对照组明显减少(P < 0.05),神经元轴突长度较对照组明显延长      (P < 0.05),但两组轴突的分叉数目差异无显著性意义(P > 0.05)。结果证实胰岛素样生长因子1可以增加神经干细胞向神经元的分化比例并促进神经干细胞源性神经元轴突长度的延伸,但不能增加轴突的分叉数量。      

Insulin-like growth factor II mRNA binding protein 1 modulates Rev-dependent human immunodeficiency virus type 1 RNA expression

Human immunodeficiency virus type 1 (HIV-1) needs to overcome cellular counter mechanisms such as to successfully propagate itself. Results of our recent studies show that overexpression of insulin-like growth factor II mRNA binding protein 1 (IMP1) inhibits production of infectious HIV-1 particles through adversely affecting virus maturation. Here, we report that IMP1 interacts with HIV-1 Rev protein and its ectopic expression causes relocation of Rev from the nucleus to the cytoplasm. In accordance with this observation, ectopic expression of IMP1 severely diminishes Rev-dependent expression of CAT enzyme and disturbs HIV-1 RNA expression by causing accumulation of the multiple spliced viral RNA. Results of mutagenesis analysis further reveal that the KH4 domain represents the key element of IMP1 in modulating HIV-1 RNA expression. Taken together, these data suggest, in addition to hampering virus assembly, that IMP1 also has an effect on Rev-dependent viral RNA expression.