Loss of IGF-II imprinting in endometrial tumors: overexpression in carcinosarcoma

Ovarian carcinosarcoma: Current developments and future perspectives

Ovarian carcinosarcoma (OCS) constitute uncommon malignancies accounting for only 1-4% of ovarian cancers. Patients more often present with advanced stage disease and symptoms similar to those of epithelial ovarian cancers (EOC). Optimal tumor cytoreduction appears to be an important determinant of survival. Platinum-based chemotherapy remains the most commonly employed adjuvant treatment. The uncertain origin and poor prognosis of OCS motivate determination of the molecular basis of carcinosarcomas aggressive behavior in the hope of developing novel and effective treatment modalities. The present review summarizes the current knowledge on the epidemiology, pathology, prognostic factors, clinical presentation, and therapeutic interventions including future potential therapeutic targets.

Insulin-like growth factor 2: a poor prognostic biomarker linked to racial disparity in women with uterine carcinosarcoma

The objective of this study was to investigate the relationship of insulin‐like growth factor 2 (IGF2) expression and survival in women with uterine carcinosarcoma (UCS). Insulin‐like growth factor 2 protein expression was determined by immunohistochemical staining of tumor tissues from 103 patients with UCS. The H‐score (product of staining intensity and percentage positive cells) was quantified for the epithelial cytoplasmic (EC), epithelial nuclear (EN), and malignant stromal compartments. Multivariable Cox proportional hazard regression models were used to examine the relationship of IGF2 levels with progression‐free survival (PFS) and overall survival (OS). Adjusting for stage, race, and adjuvant therapy, PFS and OS were reduced in patients with high IGF2 (H‐score ≥ median) in the EC and EN compartments. Black race was independently associated with reduced PFS and OS in patients with early‐stage disease, and IGF2 levels in the EC were higher in black than in white patients (P = 0.02, Wilcoxon test). In a race‐stratified multivariable analysis, high IGF2 in the epithelial compartments more than doubled the risk of death in black women; HR = 2.43 (95% CI: 1.18–5.01, P = 0.02) for high IGF2 in the EC; and HR = 2.34 (95% CI: 1.25–4.39, P = 0.008) for high IGF2 in the EN. In conclusion, high tumor IGF2 expression is an independent risk factor for reduced PFS and OS in UCS. Black women have elevated tumor IGF2 compared with white women, and decreased survival associated with high IGF2. These findings identify IGF2 as a candidate biomarker for survival linked to racial disparity in women with UCS.

Endometrial Carcinoma: Specific Targeted Pathways

Endometrial cancer (EC) is the most common gynecologic malignancy in the western world with more than 280,000 cases per year worldwide. Prognosis for EC at early stages, when primary surgical resection is the most common initial treatment, is excellent. Five-year survival rate is around 70 %.Several molecular alterations have been described in the different types of EC. They occur in genes involved in important signaling pathways. In this chapter, we will review the most relevant altered pathways in EC, including PI3K/AKT/mTOR, RAS-RAF-MEK-ERK, Tyrosine kinase, WNT/β-Catenin, cell cycle, and TGF-β signaling pathways. At the end of the chapter, the most significant clinical trials will be briefly discussed.This information is important to identify specific targets for therapy.

Tumor Phenotype and Gene Expression During Early Mammary Tumor Development in Offspring Exposed to Alcohol In Utero

BACKGROUND

Alcohol exposure in utero increases susceptibility to carcinogen-induced mammary tumorigenesis in adult offspring and causes tumors with a more malignant phenotype. This study was conducted to identify changes early in tumor development that might lead to this outcome.

METHODS

Pregnant Sprague-Dawley rats were fed a liquid diet containing 6.7% ethanol (alcohol), an isocaloric liquid diet without alcohol (pair-fed), or rat chow ad libitum (ad lib) from gestation day 7 until parturition. At birth, female progeny were cross-fostered to control dams. Pups were weaned at postnatal day (PND) 21 and fed rat chow ad libitum for the remainder of the experiment. Female offspring were administered N-nitroso-N-methylurea (NMU; 50 mg/kg body weight) on PND 50. Mammary glands were palpated weekly, and offspring were euthanized at 16 weeks post-NMU injection.

RESULTS

At 16 weeks post-NMU, tumor multiplicity was greater in alcohol-exposed offspring compared with control groups. Estrogen receptor-α (ER) mRNA expression was decreased in tumors from alcohol-exposed offspring, and these animals developed more ER-negative tumors relative to the pair-fed group. Alcohol-exposed offspring also tended to develop more progesterone receptor (PR)-positive tumors. All tumors were HER2-negative. PR positivity was associated with higher Ki67 expression, suggesting that PR-positive tumors were more proliferative. Tumors from alcohol-exposed animals exhibited increased mRNA expression of the insulin-like growth factor (IGF) family members IGF-II and IGFBP-5. IGF-II and DNA methyltransferase mRNA tended to be greater in the normal contralateral mammary glands of these animals.

CONCLUSIONS

These data indicate that alcohol exposure in utero may shift NMU-induced tumor development toward a more aggressive phenotype and that alterations in IGF-II expression may contribute to these changes. Additional studies should be aimed at epigenetic mechanisms that underlie IGF-II expression to further delineate how this gene is altered in mammary glands of adults exposed to alcohol in utero.

Conventional chemotherapy and oncogenic pathway targeting in ovarian carcinosarcoma using a patient-derived tumorgraft

Ovarian carcinosarcoma is a rare subtype of ovarian cancer with poor clinical outcomes. The low incidence of this disease makes accrual to large clinical trials challenging. However, studies have shown that treatment responses in patient-derived xenograft (PDX) models correlate with matched-patient responses in the clinic, supporting their use for preclinical testing of standard and novel therapies. An ovarian carcinosarcoma PDX is presented herein and showed resistance to carboplatin and paclitaxel (similar to the patient) but exhibited significant sensitivity to ifosfamide and paclitaxel. The PDX demonstrated overexpression of EGFR mRNA and gene amplification by array comparative genomic hybridization (log2 ratio 0.399). EGFR phosphorylation was also detected. Angiogensis and insulin-like growth factor pathways were also implicated by overexpression of VEGFC and IRS1. In order to improve response to chemotherapy, the PDX was treated with carboplatin/paclitaxel with or without a pan-HER and VEGF inhibitor (BMS-690514) but there was no tumor growth inhibition or improved animal survival, which may be explained by a KRAS mutation. Resistance was also observed when the IGF-1R inhibitor BMS-754807 was combined with carboplatin/paclitaxel. Because poly (ADP-ribose) polymerase inhibitors have activity in ovarian cancer patients, with and without BRCA mutations, ABT-888 was also tested but found to have no activity. Pathogenic mutations were also detected in TP53 and PIK3CA. In conclusion, ifosfamide/paclitaxel was superior to carboplatin/paclitaxel in this ovarian carcinosarcoma PDX and gene overexpression or amplification alone was not sufficient to predict response to targeted therapy. Better predictive markers of response are needed.

An open-label, phase 2 study evaluating the efficacy and safety of the anti-IGF-1R antibody cixutumumab in patients with previously treated advanced or metastatic soft-tissue sarcoma or Ewing family of tumours

BACKGROUND

Cixutumumab (IMC-A12), a fully human immunoglobulin G1 (IgG1) monoclonal antibody, exerts preclinical activity in several sarcoma models and may be effective for the treatment of these tumours.

METHODS

In this open-label, multicentre, phase 2 study, patients with previously treated advanced or metastatic rhabdomyosarcoma, leiomyosarcoma, adipocytic sarcoma, synovial sarcoma or Ewing family of tumours received intravenous cixutumumab (10mg/kg) for 1h every other week until disease progression or discontinuation. The primary end-point was the progression-free survival rate (PFR), defined as stable disease or better at 12 weeks. In each tier of disease histology, Simon's optimum 2-stage design was applied (PFR at 12 weeks P0=20%, P1=40%, α=0.10, β=0.10). Stage 1 enrolled 17 patients in each disease group/tier, with at least four patients with stable disease or better required at 12 weeks to proceed to stage 2.

RESULTS

A total of 113 patients were enrolled; all tiers except adipocytic sarcoma were closed after stage 1 due to futility. The 12-week PFR was 12% for rhabdomyosarcoma (n=17), 14% for leiomyosarcoma (n=22), 32% for adipocytic sarcoma (n=37), 18% for synovial sarcoma (n=17) and 11% for Ewing family of tumours (n=18). Median progression-free survival (weeks) was 6.1 for rhabdomyosarcoma, 6.0 for leiomyosarcoma, 12.1 for adipocytic sarcoma, 6.4 for synovial sarcoma and 6.4 for Ewing family of tumours. Among all patients, the most frequent treatment-emergent adverse events (AEs) were nausea (26%), fatigue (23%), diarrhoea (23%) and hyperglycaemia (20%).

CONCLUSIONS

Patients with adipocytic sarcoma may benefit from treatment with cixutumumab. Cixutumumab treatment was well tolerated, with limited gastrointestinal AEs, fatigue and hyperglycaemia.

Biology and significance of signalling pathways activated by IGF-II

Insulin-like growth factor-II (IGF-II) affects many aspects of cellular function through its ability to activate several different receptors and, consequently, numerous intracellular signalling molecules. Thus, IGF-II is a key regulator of normal foetal development and growth. However, abnormalities in IGF-II function are associated with cardiovascular disease and cancer. Here, we review the cellular mechanisms by which IGF-II's physiological and pathophysiological actions are exerted by discussing the involvement of the type 1 and type 2 IGF receptors (IGF1R and IGF2R), the insulin receptor and the downstream MAP kinase, PI-3 kinase and G-protein-coupled signalling pathways in mediating IGF-II stimulated cellular proliferation, survival, differentiation and migration.

Developmental reprogramming of IGF signaling and susceptibility to endometrial hyperplasia in the rat

In rodents, a brief neonatal exposure of the developing reproductive tract to the xenoestrogen, diethylstilbestrol (DES) reprograms developing tissues to increase susceptibility to tumorigenesis in adult animals, including uterine adenocarcinoma. Progression from a normal endometrium to carcinoma occurs via the intermediate stage of endometrial hyperplasia. We previously reported that endometrial hyperplasia in postmenopausal women is linked to abnormal insulin-like growth factor-I (IGF-I) signaling. To identify early events involved in the development of hyperplasia in the endometrium, we examined expression and activation of IGF-I pathway components in endometrium of rats exposed to DES. By 5 months of age, 36/60 (60%) of rats exposed to DES on days 3-5 after birth developed endometrial hyperplasia compared to 0% of vehicle-treated controls. Consistent with activation of a mitogenic signaling pathway, Ki67-positive cells increased in DES-exposed endometrium despite compromised ovarian function and hypoestrogenic milieu characteristic of DES-exposed animals. The endometrium of DES-exposed rats overexpressed IGF-II and insulin receptor substrate-1 (IRS-1) and exhibited elevated Akt expression and activation (as judged by phosphorylation) and mTOR signaling (phosphorylation of S6) compared to vehicle-treated endometrium. In contrast to vehicle-treated endometrium, in which negative feedback to IRS-1 was observed (phosphorylation of S636/639), negative feedback to IRS-1 was absent in DES-exposed endometrium. These data support a central role for IGF-I signaling in the development of both human and rodent endometrial hyperplasia. Furthermore, both global activation of IGF-IR signaling and abrogation of negative feedback to IRS-1 appear to be reprogrammed by DES in endometrial hyperplasia, implicating for the first time loss of negative feedback to IRS-1 in development of a preneoplastic lesion.

Insulin-like growth factor (IGF) 1 and 2 help to predict disease outcome in GIST patients

BACKGROUND

The expression of the insulin-like growth factor (IGF) system has never been studied in gastrointestinal stromal tumors (GISTs).

PATIENTS AND METHODS

We studied the immunohistochemical expression of IGF1 receptor (IGFR-I), IGF1 and IGF2 in 94 samples of GISTs. IGF1 and IGF2 expression was scored in three classes: negative (N), moderate (M) and strong (S), according to staining intensity and extent.

RESULTS

IGFR-I was overexpressed in all cases. IGF1 and IGF2 expression was absent in 25 and 48 cases, moderate in 29 and 16 cases and strong in 40 and 30 cases, respectively. Strong IGF1 expression significantly correlated with higher mitotic index (P = 0.0001), larger (P = 0.01), higher risk (P = 0.0002), metastatic (P = 0.0001) and relapsed (P = 0.04) GISTs. Strong IGF2 expression correlated with higher mitotic index (P = 0.05) and higher risk GISTs (P = 0.001). The Kaplan-Meier analysis (N versus M versus S) showed a significant worsening of the disease-free survival (DFS) with the increase of IGF1 (P = 0.02) and IGF2 (P = 0.02) expression. In the subgroup of patients with operated high-risk GISTs, there was a better trend in DFS for patients affected by GISTs with negative IGF1 and IGF2.

CONCLUSIONS

The expression of IGF1 and IGF2 seems to predict relapse in GIST patients.

Insulin-like growth factor 2 and its receptors (IGF 1R and IGF 2R/mannose 6-phosphate) in endometrial adenocarcinoma

OBJECTIVE

To investigate the consequences of IGF proteins dysfunction in development of endometrial adenocarcinomas.

METHODS

The expression of IGF 2 and IGF 1R was correlated with the expression of IGF 2R and apoptosis rate in 59 human endometrial adenocarcinomas, 10 endometrial hyperplasias and 7 normal tissues. The presence of mutations in the IGF 2R gene was followed in 46 adenocarcinomas. We also examined the effect of IGF 1 receptor blockage on cancer cell proliferation. In groups of either IGF 2-positive or IGF 2-negative tumors (stages III and IV) the expression of IGF 1 and IGF 1R was correlated with cell proliferation index and telomerase activity.

RESULTS

The expression of IGF 2 and IGF 1R was much higher in malignant tissue of stages III and IV than in tumors of stages I and II and normal or hyperplastic endometrium. This correlated with a decreased apoptosis rate and IGF 2R expression. Eight adenocarcinomas expressed biallelic mutation of the IGF 2R gene. The specific inhibition of IGF 1R and IGF 2 decreased tumor cell proliferation in IGF 2/IGF 1R-positive tumors. Furthermore, the positive correlation between increased expression of IGF 1 and IGF 1R proteins and increased telomerase activity and cell proliferation index was found in both IGF 2-negative and IGF 2-positive tumors.

CONCLUSION

Our data suggest that IGF 1, IGF 2 and their receptors are involved in the progression of endometrial adenocarcinomas. As cancer cell proliferation can be abrogated by blocking mRNA or protein products of these genes, tumors with extensive involvement of the IGF 2 pathway would be candidates for the therapeutics strategies aimed at interference with this pathway.

Genomic imprinting of IGF2 is maintained in infantile hemangioma despite its high level of expression

Hemangioma, the most common tumor of infancy, is characterized by rapid growth and slow regression. Increased mRNA expression of insulin-like growth factor 2 (IGF2) has been detected in the proliferating phase by cDNA microarray analysis, but the underlying mechanism causing the increase remains unknown. Here, using quantitative real-time polymerase chain reaction (PCR) and immunohistochemistry, we show that IGF2 is highly expressed in both proliferating and involuting phase hemangioma, but is not detectable in other vascular lesions such as pyogenic granuloma, venous malformation, lymphatic malformation, or in normal infant skin. Loss of imprinting of the Igf2 gene has been associated with IGF2 overexpression in a variety of childhood tumors. To determine if loss of imprinting and consequent bi-allelic expression might contribute to the increased expression of IGF2, we examined the genomic imprinting status of Igf2 in 48 individual hemangiomas. We determined allele-specific Igf2 expression using reverse transcriptase-PCR combined with analysis of an Apa I-sensitive restriction fragment length polymorphism. Similar to heterozygous normal skin controls, all 15 informative hemangiomas showed uniform mono-allelic expression of Igf2. Therefore, loss of imprinting is not involved in the increased expression of IGF2 in infantile hemangioma.

Microarray Analysis of Endometrial Carcinomas and Mixed Mullerian Tumors Reveals Distinct Gene Expression Profiles Associated with Different Histologic Types of Uterine Cancer

Previous studies using cDNA microarray have indicated that distinct gene expression profiles characterize endometrioid and papillary serous carcinomas of the endometrium. Molecular studies have observed that mixed mullerian tumors, characterized by both carcinomatous and sarcomatous components, share features that are characteristic of endometrial carcinomas. The objective of this analysis was to more precisely define gene expression patterns that distinguish endometrioid and papillary serous histologies of endometrial carcinoma and mixed mullerian tumors of the uterus. One hundred nineteen pathologically confirmed uterine cancer samples were studied (66 endometrioid, 24 papillary serous, and 29 mixed mullerian tumors). Gene expressions were analyzed using the Affymetrix Human Genome Arrays U133A and U133B Genechip set. Unsupervised analysis revealed distinct global gene expression patterns of endometrioid, papillary serous, mixed mullerian tumors, and normal tissues as grossly separated clusters. Two-sample t tests comparing endometrioid and papillary serous, endometrioid and mixed mullerian tumor, and papillary serous and mixed mullerian tumor pairs identified 1,055, 5,212, and 1,208 differentially expressed genes at P < 0.001, respectively. These data revealed that distinct patterns of gene expression characterize various histologic types of uterine cancer. Gene expression profiles for select genes were confirmed using quantitative PCR. An understanding of the molecular heterogeneity of various histologic types of endometrial cancer has the potential to lead to better individualization of treatment in the future.

Loss of imprinting of IGF-II gene in children with acute lymphoblastic leukemia

Insulin-like growth factor-II (IGF-II) is known to be involved in the regulation of growth, differentiation and cell death in normal human tissues. In a variety of human tumors, the IGF-II gene is overexpressed and considered to be a stimulator for tumor growth through autocrine and paracrine mechanisms. The IGF-II gene is normally parental imprinted, only the paternal allele being expressed in most tissues. Several reports about biallelic expression (loss of imprinting (LOI)) of the IGF-II gene in different tumors suggest a role of dysregulation of IGF-II imprinting in tumorigenesis. However, biallelic expression of IGF-II gene has also been reported in different tissues of a significant number of normal controls, indicating either a normal phenomenon or an elevated cancer risk in this group of persons. Although LOI of IGF-II presumably promotes tumorigenesis by increasing IGF-II expression, elevated IGF-II levels in those patients have not been reported. We studied IGF-II gene expression in malignant lymphoblasts of 124 children suffering from acute lymphoblastic leukemia, 196 cord blood samples from healthy newborns and mononuclear cells (MNC) from 50 healthy age matched children. The ApaI polymorphism in exon 9 of the IGF-II gene and allele-specific exon-connection RT-PCR was used for determination of the imprinting status. From 44 informative ALL-patients, 24 (54%) showed LOI of the IGF-II gene. Twenty percent of the informative cord blood samples (N=56) and 14% of the informative MNC samples from healthy controls (N=22) showed biallelic expression of IGF-II. In the ALL-patients, no statistical significant correlation between LOI patients and relapse rate, surviving rate and risk groups could be detected. We conclude that LOI of IGF-II occurs in malignant lymphoblasts of children suffering from acute lymphoblastic leukemia in more than 50% of the patients. In MNC from cord blood and peripheral MNC from healthy controls, biallelic expression could be detected in up to 20% of all cases. The importance of LOI in ALL-patients needs to be further evaluated to determine its impact in leukemogenesis.

Effects of insulin-like growth factors-IR and -IIR antisense gene transfection on the biological behaviors of SMMC-7721 human hepatoma cells

BACKGROUND AND AIMS

Insulin-like growth factors (IGFs) are closely related to hepatocellular carcinoma growth. The study aim was to investigate the effects of IGF-IR and IGF-IIR antisense gene transfection on the biological behaviors of SMMC-7721 human hepatoma cells.

METHODS

7721-IGF-IR-AS cells (human hepatoma SMMC-7721 cells transfected with IGF-IR antisense gene in our previous study) were transfected with a plasmid vector expressing IGF-IIR cDNA in the antisense orientation by DOTAP liposome.7721-IGF-R-AS cells were obtained by selection with G418 and hygromycin. Morphological changes of the cells were observed with optic and electron microscopes. In vitro growth of the 7721-IGF-R-AS cells was observed with a soft agar test, MTT test and with naked mice inoculation test in vivo.

RESULTS

The following changes were found in the SMMC-7721 cells after being transfected with the IGF-IR and IGF-IIR antisense genes: (i) the degree of malignancy of the tumor cells as revealed by cell morphology was ameliorated; (ii) the growth capability of the tumor cells in soft agar and their tumorigenicity in naked mice were significantly depressed. However, in the control groups, the SMMC-7721 cells transfected both with IGF-IR and IGF-IIR sense cDNA and SMMC-7721 cells transfected without any external genes, had no such changes. However, the cell growth curves had no significant differences among these three groups.

CONCLUSION

IGF-IR and IGF-IIR antisense genes could significantly restrain the malignant behavior of human hepatoma cells and might be useful in investigating a potential route for hepatocellular carcinoma gene therapy.