Gene expression of insulin-like growth factor II in human intracranial meningioma

Abstract

Background. Insulin‐like growth factor II (IGF‐II) is synthesized in the normal brain of adult humans predominantly in the choroid plexus and meninges and is secreted in the cerebrospinal fluid. The authors measured IGF‐II transcripts and peptides in biopsy specimens from human intracranial tumors including astrocytomas, glioblastomas, and meningiomas. Methods. The presence of IGF‐II mRNA was analyzed in 12 human brain tumors by Northern analysis of total RNA extracted from tumor biopsies and by in situ hybridization of tissue sections. The amount of immunoreactive IGF‐II was determined by radioimmunoassay of tumor extracts. Results. Northern analysis of RNA from four meningiomas showed IGF‐II mRNA of 6.0, 4.8, and 2.2 kb, and in situ hybridization revealed that meningioma tumor cells contained IGF‐II mRNA. In contrast, biopsy specimens from four astrocytomas, one oligoastrocytoma, and four glioblastomas showed no IGF‐II mRNA. Radioimmunoassay of IGF‐II in tumor extracts showed that all tumors contained IGF‐II (40–160 ng/g tissue). Two meningiomas contained the highest amounts of IGF‐II (144 and 160 ng/g tissue). Conclusions. IGF‐II mRNA is present in higher amounts in benign meningiomas than in malignant glioblastomas and astrocytomas, whereas the content of immunoreactive IGF‐II is similar. On the basis of these findings, the authors believe that IGF‐II may be involved in growth regulation of meningiomas.

Identification of IGF2 signaling through phosphoinositide-3-kinase regulatory subunit 3 as a growth-promoting axis in glioblastoma

“…In mouse models, OE of IGF2 can lead to the development of lung tumors (18,19), loss of IGF2 imprinting promotes development of intestinal tumors (20), and IGF2 has been shown to play an essential role in the induction of medulloblastomas (21). Although previous findings reported loss of imprinting and OE of IGF2 in human meningiomas (22,23), reports on IGF2 expression in glioma have not yielded a consistent picture (24,25).…”

The IGF/IGFBP system in CNS malignancy

“…11 IGF-II mRNA was found in higher amounts in benign meningiomas than in malignant glioblastomas and astrocytomas, whereas the content of immunoreactive IGF-II peptide was comparable. 12 IGF-II mRNA expression appears to parallel the growth rate in the LI human glioblastoma cell line. 13 Upregulation of IGF-II expression is a feature of TrkA but not TrkB activation in SH-SY5Y neuroblastoma cells, suggesting that IGF-II is a component of the eVector mechanism of TrkA activation.…”

New Biomarkers for Cervical Cancer – Perspectives from the IGF System

“…There is ample evidence that the levels of IGF-II mRNA differ from the protein. While IGF-II transcripts were higher than in normal tissue in prostate cancer (Tennant et al, 1996), Wilms tumors (Haselbacher et al, 1987), and glioblastomas and astrocytomas (Hultberg et al, 1993), it was not the case for the protein. High levels of IGF-II protein, but not mRNA were found in pheocromocytomas (Haselbacher et al, 1987).…”