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

MicroRNAs, long non-coding RNAs, and circular RNAs and gynecological cancers: focus on metastasis

Gynecologic cancer is a significant cause of death in women worldwide, with cervical cancer, ovarian cancer, and endometrial cancer being among the most well-known types. The initiation and progression of gynecologic cancers involve a variety of biological functions, including angiogenesis and metastasis-given that death mostly occurs from metastatic tumors that have invaded the surrounding tissues. Therefore, understanding the molecular pathways underlying gynecologic cancer metastasis is critical for enhancing patient survival and outcomes. Recent research has revealed the contribution of numerous non-coding RNAs (ncRNAs) to metastasis and invasion of gynecologic cancer by affecting specific cellular pathways. This review focuses on three types of gynecologic cancer (ovarian, endometrial, and cervical) and three kinds of ncRNAs (long non-coding RNAs, microRNAs, and circular RNAs). We summarize the detailed role of non-coding RNAs in the different pathways and molecular interactions involved in the invasion and metastasis of these cancers.

Landscape of PCOS co-expression gene and its role in predicting prognosis and assisting immunotherapy in endometrial cancer

BACKGROUND

Endometrial carcinoma (EC) is the sixth most frequent malignancy in women and is often linked to high estrogen exposure. Polycystic ovarian syndrome (PCOS) is a known risk factor for EC, but the underlying mechanisms remain unclear.

METHODS

We investigated shared gene signals and potential biological pathways to identify effective therapy options for PCOS- and EC-related malignancies. Weighted gene expression network analysis (WGCNA) was used to identify genes associated with PCOS and EC using gene expression data from the Gene Expression Omnibus (GEO) and Cancer Genome Atlas (TCGA) datasets. Enrichment analysis using Cluego software revealed that the steroid hormone biosynthetic process was a critical feature in both PCOS and EC. A predictive signature encompassing genes involved in steroid hormone production was developed using multivariate and least absolute shrinkage and selection operator (LASSO) regression analysis to predict the prognosis of EC. Then, we conducted further experimental verification.

RESULTS

Patients in the TCGA cohort with high predictive scores had poorer outcomes than those with low scores. We also investigated the relationship between tumor microenvironment (TME) features and predictive risk rating and found that patients with low-risk scores had higher levels of inflammatory and inhibitory immune cells. Also, we found that immunotherapy against anti-CTLA4 and anti-PD-1/PD-L1 was successful in treating individuals with low risk. Low-risk individuals were more responsive to crizotinib therapy, according to further research performed using the "pRRophetic" R package. We further confirmed that IGF2 expression was associated with tumor cell migration, proliferation, and invasion in EC cells.

CONCLUTIONS

By uncovering the pathways and genes linking PCOS and EC, our findings may provide new therapeutic strategies for patients with PCOS-related EC.

Receptor Tyrosine Kinases and Their Signaling Pathways as Therapeutic Targets of Curcumin in Cancer

Receptor tyrosine kinases (RTKs) are transmembrane cell-surface proteins that act as signal transducers. They regulate essential cellular processes like proliferation, apoptosis, differentiation and metabolism. RTK alteration occurs in a broad spectrum of cancers, emphasising its crucial role in cancer progression and as a suitable therapeutic target. The use of small molecule RTK inhibitors however, has been crippled by the emergence of resistance, highlighting the need for a pleiotropic anti-cancer agent that can replace or be used in combination with existing pharmacological agents to enhance treatment efficacy. Curcumin is an attractive therapeutic agent mainly due to its potent anti-cancer effects, extensive range of targets and minimal toxicity. Out of the numerous documented targets of curcumin, RTKs appear to be one of the main nodes of curcumin-mediated inhibition. Many studies have found that curcumin influences RTK activation and their downstream signaling pathways resulting in increased apoptosis, decreased proliferation and decreased migration in cancer both in vitro and in vivo. This review focused on how curcumin exhibits anti-cancer effects through inhibition of RTKs and downstream signaling pathways like the MAPK, PI3K/Akt, JAK/STAT, and NF-κB pathways. Combination studies of curcumin and RTK inhibitors were also analysed with emphasis on their common molecular targets.

Gimap5 Inhibits Lung Cancer Growth by Interacting With M6PR

Objective

Several studies have demonstrated the impacts of GTPases of immunity-associated proteins (GIMAPs) on malignant cells. However, the mechanisms through which Gimap5 regulates lung cancer cells are yet to be thoroughly investigated in the literature. Our study aimed to investigate the function of Gimap5 in the development of lung cancer.

Methods

The expression levels of the GIMAP family were analyzed in lung cancer patients of various cancer databases and lung cancer cell lines. After the survival rates of the cells were analyzed, we constructed Gimap5 over-expressed lung cancer cell lines and assessed the effects of Gimap5 on cell migration, cell invasion, cell proliferation and the epithelial-mesenchymal transition (EMT). We later screened the interacting proteins of Gimap5 using Co-IP combined with mass spectrometry and then analyzed the expression and distribution of M6PR, including its impacts on protein-arginine deiminase type-4 (PADI4).

Results

Findings indicated that GIMAP family expression decreased significantly in lung cancer cell lines. We also noticed that the downregulation of the GIMAP family was related to the poor prognosis of lung cancer patients. Our experimental results showed that Gimap5 could inhibit the migration, invasion, proliferation and EMT of lung cancer cell lines. Moreover, we found that Gimap5 promoted the transport of M6PR from the cytoplasm to the cell membrane, thereby inhibiting the enhancement of EMT-related PADI4.

Conclusion

Our research suggested that Gimap5 could inhibit the growth of lung cancer by interacting with M6PR and that it could be a potential biomarker for the diagnosis and prognosis of lung cancer.

Immunohistochemical expression of insulin-like growth factor-1Ec in primary endometrial carcinoma: Association with PTEN, p53 and survivin expression

Chronic hyperinsulinemia due to insulin resistance and elevated levels of insulin-like growth factor (IGF)-1 and IGF-2 are suggestive of a significantly higher risk of endometrial carcinoma. There is a wealth of evidence showing differential expression of IGF-1 isoforms in various types of cancer. In the present study, 99 archived endometrial carcinoma tissue sections were retrospectively assessed by immunohistochemistry for IGF-1Ec isoform expression. Expression of IGF-1Ec was also assessed in nine cases of non-neoplastic endometrial tissue adjacent to the tumor, in 30 cases with normal endometrium and in 30 cases with endometrial hyperplasia. Furthermore, the association between IGF-1Ec and the concurrent expression of phosphatase and tensin homologue deleted on chromosome 10 (PTEN), p53 or survivin was assessed, as well as their combined expression in association with clinicopathological variables. In endometrial carcinoma, IGF-1Ec expression was high in non-endometrioid carcinoma (serous papillary or clear cell carcinoma) compared with that in endometrioid adenocarcinoma. IGF-1Ec expression was also high in the presence of tumoral necrosis. Furthermore, there was a significant correlation between the histological differentiation and the sum of staining intensity and the number of IGF-1Ec immunopositive cells in endometrial carcinoma. There was a moderate negative correlation between co-expression of IGF-1Ec and PTEN, for both the number of immunopositive cells (P=0.006, ρ=−0.343) and the sum of staining (scores and intensity; P=0.006, ρ=−0.343). Furthermore, there was a positive correlation between the sum of staining (scores and intensity) and co-expression of IGF-1Ec and survivin (P=0.043, ρ=0.225). However, there was no association between concomitant expression of IGF-1Ec and p53. These results emphasized the importance of IGF-1Ec expression during development of non-estrogen dependent endometrial adenocarcinoma. IGF-1Ec and PTEN may function opposingly during endometrial carcinogenesis. By contrast, IGF-1Ec and survivin may share common molecular pathways and may promote, in parallel, tumoral development.

CircRNA hsa_circ_0002577 accelerates endometrial cancer progression through activating IGF1R/PI3K/Akt pathway

Background

Endometrial cancer (EC) is a common gynecologic malignancy worldwide. This study investigated the regulatory effects of circular RNA (circRNA) hsa_circ_0002577 on the tumorigenesis of EC.

Methods

Tumor samples and adjacent normal tissues were obtained from 84 EC patients. Recombinant lentiviral vectors expressing hsa_circ_0002577 (Lv-circRNA), short hairpin RNAs against hsa_circ_0002577 (sh-circRNA), miR-625-5p mimics, miR-625-5p inhibitor, lentiviral vectors expressing insulin-like growth factor 1 receptor (IGF1R) and their corresponding controls were transfected into EC cells as designated. A mouse xenograft model was established in BALB/c mice by inoculating Ishikawa cells transfected with sh-circRNA or control sequence.

Results

Hsa_circ_0002577 was upregulated in EC tissue samples and cells as compared to normal controls. EC patients with higher expression of hsa_circ_0002577 showed poorer overall survival and more advanced tumor stage. EC cells transfected with Lv-circRNA showed promoted proliferation, migration, and invasion, whereas the delivery of sh-circRNA exerted an opposite effect. Further analyses showed that hsa_circ_0002577 acted as a miR-625-5p sponge in EC cells. IGF1R was a potential downstream target of miR-625-5p. The expression of IGF1R in EC tissues was significantly higher than that in matched controls. Hsa_circ_0002577 accelerated EC development by inducing IGF1R expression and activating PI3K/Akt signaling pathway. Also, the knockdown of hsa_circ_0002577 delayed tumor growth and metastasis in the inoculated mice.

Conclusion

Our study showed that circRNA hsa_circ_002577 accelerated EC progression by acting as a miR-625-5p sponge, upregulating IGF1R and activating the PI3K/Akt pathway, suggesting the potential therapeutic use of hsa_circ_002577 in EC treatment.

Trial registration

Not Applicable.

Adipocytokines and their relationship to endometrial cancer risk: A systematic review and meta-analysis

OBJECTIVE

To investigate the association between circulating levels of adipocytokines (adiponectin, leptin, tumour necrosis factor alpha (TNFα), interleukin 6 (IL-6)) and growth factors (insulin-like growth factor I (IGF-I) and II (IGF-II)), and the risk of endometrial cancer.

METHODS

Cochrane, CINAHL, Embase, Medline and Web of Science were searched for English-language manuscripts published between January 2000 and August 2018 using the following string of words: cancer and endometrial and (obesity or BMI) and (adiponectin or TNF* or IGF-I or IGF-II or IL-6 or leptin).

RESULTS

Twenty articles were included in this meta-analysis, which corresponded to 18 studies involving 2921 endometrial carcinoma cases and 5302 controls. Fourteen articles reported circulating levels for adiponectin, seven for leptin, three for TNFα, three for IL-6 and one for IGF-I. No article reported values for IGF-II. Patients with circulating adiponectin levels in the highest tertile had decreased endometrial cancer risk compared to women with levels in the lowest tertile, (summary of odds ratio (SOR) 0.51, 95% confidence interval (CI): 0.38-0.69, p < 0.00001). Women with circulating leptin concentrations in the highest tertile had increased endometrial cancer risk compared to women with concentrations in the lowest tertile (SOR 2.19, 95% CI: 1.45-3.30, p = 0.0002). There was no difference in cancer risk between participants with the highest TNFα and IL-6 levels compared to the lowest levels (SOR 1.27, 95% CI: 0.88-1.83, p = 0.20 and SOR 1.20, 95% CI: 0.89-1.63, p = 0.23, respectively).

CONCLUSIONS

Endometrial cancer risk is inversely affected by adiponectin and leptin levels. There appears to be no relationship between TNFα and IL-6 and the overall risk of endometrial cancer.

Critical role of SOX2-IGF2 signaling in aggressiveness of bladder cancer

Signaling elicited by the stem cell factors SOX2, OCT4, KLF4, and MYC not only mediates reprogramming of differentiated cells to pluripotency but has also been correlated with tumor malignancy. In this study, we found SOX2 expression signifies poor recurrence-free survival and correlates with advanced pathological grade in bladder cancer. SOX2 silencing attenuated bladder cancer cell growth, while its expression promoted cancer cell survival and proliferation. Under low-serum stress, SOX2 expression promoted AKT phosphorylation and bladder cancer cells’ spheroid-forming capability. Furthermore, pharmacological inhibition of AKT phosphorylation, using MK2206, inhibited the SOX2-mediated spheroid formation of bladder cancer cells. Gene expression profiling showed that SOX2 expression, in turn, induced IGF2 expression, while SOX2 silencing inhibited IGF2 expression. Moreover, knocking down IGF2 and IGF1R diminished bladder cancer cell growth. Lastly, pharmacological inhibition of IGF1R, using linsitinib, also inhibited the SOX2-mediated spheroid formation of bladder cancer cells under low-serum stress. Our findings indicate the SOX2–IGF2 signaling affects the aggressiveness of bladder cancer cell growth. This signaling could be a promising biomarker and therapeutic target for bladder cancer intervention.

Near-Infrared Fluorescent Imaging for Monitoring of Treatment Response in Endometrial Carcinoma Patient-Derived Xenograft Models

Imaging of clinically relevant preclinical animal models is critical to the development of personalized therapeutic strategies for endometrial carcinoma. Although orthotopic patient-derived xenografts (PDXs) reflecting heterogeneous molecular subtypes are considered the most relevant preclinical models, their use in therapeutic development is limited by the lack of appropriate imaging modalities. Here, we describe molecular imaging of a near-infrared fluorescently labeled monoclonal antibody targeting epithelial cell adhesion molecule (EpCAM) as an in vivo imaging modality for visualization of orthotopic endometrial carcinoma PDX. Application of this near-infrared probe (EpCAM-AF680) enabled both spatio-temporal visualization of development and longitudinal therapy monitoring of orthotopic PDX. Notably, EpCAM-AF680 facilitated imaging of multiple PDX models representing different subtypes of the disease. Thus, the combined implementation of EpCAM-AF680 and orthotopic PDX models creates a state-of-the-art preclinical platform for identification and validation of new targeted therapies and corresponding response predicting markers for endometrial carcinoma.

Characterization of GRP as a functional neuropeptide in basal chordate amphioxus

Amphioxus belongs to the subphylum cephalochordata, an extant representative of the most basal chordates, whose regulation of endocrine system remains ambiguous. Here we clearly demonstrated the existence of a functional GRP neuropeptide in amphioxus, which was able to interact with GRP receptor, activate both PKC and PKA pathways, increase gh, igf, and vegf expression. We also showed that the transcription level of amphioxus grp was affected by temperature and light, indicating the role of this gene in the regulation of energy balance and circadian rhythms. In addition, the expression of the amphioxus grp was detected in cerebral vesicle that has been proposed to be the homologous organ of vertebrate brain. These data collectively suggested that a functional GRP neuropeptide had already emerged in amphioxus, which provided insights into the evolutionary origin of GRP in chordate and the functional homology between the cerebral vesicle and vertebrate brain.

Picropodophyllin inhibits type I endometrial cancer cell proliferation via disruption of the PI3K/Akt pathway

The type-I insulin-like growth factor receptor (IGF-IR) is overexpressed in endometrial cancer. High IGF-IR expression was considered as an important prognostic factor for tumor progression. The purpose of this study was to investigate the role and molecular mechanism of IGF-IR inhibitor picropodophyllin (PPP) in the growth and development of endometrial cancer. High expression of IGF-IR was observed in endometrial cancer tissues, as well as in ECC-1 and KLE cell lines. PPP suppressed the number of clones of ECC-1 and KLE cell lines; however, it had no significant effect on HEC-1-A cell line, which expressed lower IGF-IR than ECC-1 and KLE cell lines. Furthermore, PPP reduced cell proliferation capacity, inhibited the IGF-IR mRNA expression, and suppressed protein phosphorylation of IGF-IR and Akt in the three cell lines. In addition, PPP inhibited the protein expression of survivin in KLE cell line after 1 h of exposure, though this effect did not last for prolonged time. In conclusion, IGF-IR was mostly overexpressed in type I endometrial cancer. High IGF-IR expression was an important prognostic factor of tumor progression. PPP mediated the down-regulation of IGF-IR phosphorylation and inhibited cell proliferation via the PI3K/Akt signal pathway. PPP may have the potential to become a clinical treatment target in endometrial carcinoma.

Immunotherapy in endometrial cancer: new scenarios on the horizon

This extensive review summarizes clinical evidence on immunotherapy and targeted therapy currently available for endometrial cancer (EC) and reports the results of the clinical trials and ongoing studies. The research was carried out collecting preclinical and clinical findings using keywords such as immune environment, tumor infiltrating lymphocytes, programmed death-1 (PD-1)/programmed death-ligand 1 (PD-L1) expression, immune checkpoint inhibitors, anti-PD-1/PD-L1 antibodies and others' on PubMed. Finally, we looked for the ongoing immunotherapy trials on ClinicalTrials.gov. EC is the fourth most common malignancy in women in developed countries. Despite medical and surgical treatments, survival has not improved in the last decade and death rates have increased for uterine cancer in women. Therefore, identification of clinically significant prognostic risk factors and formulation of new rational therapeutic regimens have great significance for enhancing the survival rate and improving the outcome in patients with advanced or metastatic disease. The identification of genetic alterations, including somatic mutations and microsatellite instability, and the definition of intracellular signaling pathways alterations that have a major role in in tumorigenesis is leading to the development of new therapeutic options for immunotherapy and targeted therapy.

Association of IGF-1 CA(n) and IGFBP3 rs2854746 Polymorphisms with Endometrial Polyp Risk

INTRODUCTION

Insulin-like growth factor 1 (IGF-1) is a peptide growth factor that promotes cell proliferation and inhibits apoptosis. The bioavailability of IGF-1 is regulated by the insulin-like growth factor binding protein 3 (IGFBP3). Genetic variations influence the levels of IGF-1 and IGFBP3. The purpose of this study was to examine the association of polymorphisms IGF-1 CA(n) and IGFBP3 rs2854746 with risk of endometrial polyps.

MATERIALS AND METHODS

Case control observational study, composed of 104 women with antecedent of endometrial polyp (case group) and 81 postmenopausal women without antecedent of endometrial diseases (control group). Genotyping of IGF-1 CA(n) was performed by PCR and fragment analysis by capillary electrophoresis, and genotyping of IGFBP3 rs2854746 was performed by PCR-HRM. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated by logistic regression.

RESULTS

The genotype IGF-1 CA(19)/CA(19) was associated with an increased endometrial polyp risk (OR=2,57; IC 95%= 1,09 - 6,01); this was also found when combining it with CA(>19)/CA(n) genotypes (OR=2,18; IC 95%= 1,06-4,47). The IGFBP3 rs2854746 analyses showed the CG genotype having a protective effect for endometrial polyp (OR=0,37; IC 95%= 0,19-0,73), fact also observed when grouping CG and GG carriers (OR=0,51; IC 95%= 0,28-0,93).

CONCLUSION

The genotypes CA(19)/CA(19) and CA(19)/CA(19) + CA(>19)/CA(n) of the IGF-1 CA(n) may be considered a risk for endometrial polyp, whereas the genotypes CG and CG + GG of IGFBP3 rs2854746 polymorphism have an inverse effect of endometrial polyp risk.

IR-A/IGF-1R-mediated signals promote epithelial-mesenchymal transition of endometrial carcinoma cells by activating PI3K/AKT and ERK pathways

BACKGROUND

Obesity is a risk factor for endometrial cancer (EC). However, it is not known how insulin receptor isoform A (IR-A) and insulin-like growth factor 1 receptor (IGF-1R), cognate receptors for insulin and IGFs, respectively, regulate malignant behaviors of EC. In this study, we examined the biological effects of IR-A/IGF-1R, explored the downstream signaling cascades, and assessed the therapeutic potential of targeting IR-A/IGF-1R in vivo.

METHODS

The expression levels of IR-A and IGF-1R were examined by qRT-PCR and Western blotting. Upon down-regulating IR-A and/or IGF-1R by sh-IR-A and/or sh-IGF-1R, respectively, cell migration, invasion, apoptosis, and epithelial-mesenchymal transition (EMT) were examined by wound healing, transwell invasion, flow cytometry, and Western blotting, respectively. Furthermore, the effect of sh-IR-A and/or sh-IGF-1R on phosphatidylinositide 3-kinases (PI3K)/AKT and ERK pathways was measured by Western blotting. Lastly, we monitored xenograft growth and EMT in vivo.

RESULTS

Both IR-A and IGF-1R were significantly up-regulated in EC cells. Knockdown of IR-A or IGF-1R alone was sufficient to reduce migration and invasion, enhance apoptosis, and inhibit EMT of EC cells, and the most significant alterations were observed in cells co-transfected with sh-IR-A+ sh-IGF-1R. These phenotypes were associated with inactivating PI3K/AKT and ERK signaling by sh-IR-A and/or sh-IGF-1R. Consistent with in vitro findings, sh-IR-A or sh-IGF-1R significantly inhibited xenograft growth and EMT in vivo.

CONCLUSION

IR-A and IGF-1R-mediated signals, by activating PI3K/AKT and ERK pathways, can induce multiple malignant phenotypes of EC cells. Therefore, targeting IR-A or IGF-1R may provide therapeutic benefits for EC.

Adiponectin, Leptin, and Insulin-Pathway Receptors as Endometrial Cancer Subtyping Markers

Developing a system of molecular subtyping for endometrial tumors might improve insight into disease etiology and clinical prediction of patient outcomes. High body mass index (BMI) has been implicated in development of endometrial cancer through hormonal pathways and might influence tumor expression of biomarkers involved in BMI-sensitive pathways. We evaluated whether endometrial tumor expression of 7 markers from BMI-sensitive pathways of insulin resistance could effectively characterize molecular subtypes: adiponectin receptor 1, adiponectin receptor 2, leptin receptor, insulin receptor (beta subunit), insulin receptor substrate 1, insulin-like growth factor 1 receptor, and insulin-like growth factor 2 receptor. Using endometrial carcinoma tissue specimens from a case-only prospective sample of 360 women from the Nurses' Health Study, we scored categorical immunohistochemical measurements of protein expression for each marker. Logistic regression was used to estimate associations between endometrial cancer risk factors, especially BMI, and tumor marker expression. Proportional hazard modeling was performed to estimate associations between marker expression and time to all-cause mortality as well as time to endometrial cancer-specific mortality. No association was observed between BMI and tumor expression of any marker. No marker was associated with time to either all-cause mortality or endometrial cancer-specific mortality in models with or without standard clinical predictors of patient mortality (tumor stage, grade, and histologic type). It did not appear that any of the markers evaluated here could be used effectively to define molecular subtypes of endometrial cancer.

MicroRNA-381 inhibits cell proliferation and invasion in endometrial carcinoma by targeting the IGF-1R

Endometrial carcinoma (EC) is the sixth most common type of malignant tumor occurring in females. MicroRNAs (miRNAs) serve as oncogenes or tumor suppressors in human cancer and play important roles in tumorigenesis, and tumor development by regulating various processes. Thus, further investigation into miRNAs involved in EC formation and progression may aid in developing effective therapeutic strategies for patients with this disease. miRNA‑381 (miR‑381) is aberrantly expressed in multiple types of human cancer. However, the expression pattern, biological roles and underlying mechanisms of miR‑381 in EC are poorly understood. In the present study, the results showed that miR‑381 was downregulated in EC tissues and cell lines. Decreased miR‑381 expression correlated with the International Federation of Gynecology and Obstetrics stage, lymph nodes metastasis and myometrial invasion of EC. The ectopic expression of miR‑381 significantly inhibited the proliferation and invasion of EC cells. Through a series of experiments, the insulin‑like growth factor receptor 1 (IGF‑1R) was identified as a novel direct target of miR‑381 in EC. Furthermore, IGF‑1R was highly expressed in EC tissues and inversely correlated with miR‑381 levels. IGF‑1R overexpression partially abrogated the tumor‑suppressive effects of miR‑381 on the proliferation and invasion of EC cells. miR‑381 targeted IGF‑1R to inactivate the protein kinase B (AKT) and extracellular signal‑regulated kinase (ERK) signaling pathways in EC. These results suggest that miR‑381 acts as a tumor suppressor in EC by directly targeting IGF‑1R, and indirectly regulating the AKT and ERK signaling pathways. Thus, miR‑381 should be investigated as a prognostic biomarker and novel therapeutic target for the treatment of patients with EC.

Leptocarpin Suppresses Proliferation, Migration, and Invasion of Human Osteosarcoma by Targeting Type-1 Insulin-Like Growth Factor Receptor (IGF-1R)

BACKGROUND Leptocarpin (LTC) has drawn much attention for suppressing tumor growth or reducing inflammation. However, the effect of LTC on osteosarcoma has rarely been reported. Our object was to determine whether LTC suppresses MG63 cell proliferation, migration, and invasion, and whether type-1 insulin-like growth factor receptor (IGF-1R) is one of the targets in LTC suppressing osteosarcoma. MATERIAL AND METHODS Cytotoxicity of LTC was performed by use of a cell-counting kit-8 (CCK-8). RNA interference (RNAi) or pEABE-bleo IGF-1R plasmid were used for silencing or overexpressing IGF-1R, Western blot (WB) analysis was used for IGF-1R expression, CCK-8 for proliferation, and transwell assay for migration and invasion. RESULTS LTC (23.533 μM) treatment for 48 h was taken as the 50% inhibiting concentration (IC50), which significantly (P<0.05) suppressed MG63 cells proliferation, migration, and invasion. LTC (IC50) obviously inhibited IGF-1R expression in MG63 cells, with similar effect to small interfering RNA (siRNA), while pEABE-bleo IGF-1R transfection overexpressed IGF-1R. siRNA silencing IGF-1R suppressed MG63 cells proliferation, migration, and invasion, while pEABE-bleo IGF-1R transfection was significantly (P<0.05) promoted. With or without siRNA or pEABE-bleo IGF-1R transfection, LTC (IC50) suppressed MG63 cells proliferation, migration, and invasion. The effect of LTC (IC50) combined with siRNA on suppressing MG63 cells proliferation, migration, and invasion was more obvious, while the effect of LTC (IC50) combined with pEABE-bleo IGF-1R transfection was less significant (P<0.05). CONCLUSIONS LTC suppressed osteosarcoma proliferation, migration, and invasion by inhibiting IGF-1R expression. IGF-1R is one of the targets in LTC suppressing osteosarcoma.

Insulin-like growth factor (IGF) axis in cancerogenesis

Determination of the role of insulin-like growth factor (IGF) family components in carcinogenesis of several human tumors is based on numerous epidemiological and pre-clinical studies, experiments in vivo and in vitro and on attempts at application of drugs affecting the IGF axis. Investigative hypotheses in original studies were based on biological functions manifested by the entire family of IGF (ligands, receptors, linking proteins, adaptor molecules). In the context of carcinogenesis the most important functions of IGF family involve intensification of proliferation and inhibition of cell apoptosis and effect on cell transformation through synthesis of several regulatory proteins. IGF axis controls survival and influences on metastases of cells. Interactions of IGF axis components may be of a direct or indirect nature. The direct effects are linked to activation of PI3K/Akt signaling pathway, in which the initiating role is first of all played by IGF-1 and IGF-1R. Activity of this signaling pathway leads to an increased mitogenesis, cell cycle progression, and protection against different apoptotic stresses. Indirect effects of the axis depend on interactions between IGF and other molecules important for cancer etiology (e.g. sex hormones, products of suppressor genes, viruses, and other GFs) and the style of life (nutrition, physical activity). From the clinical point of view, components of IGF system are first of all considered as diagnostic serous and/or tissue biomarkers of a given cancer, prognostic factors and attractive target of modern anti-tumor therapies. Several mechanisms in which IGF system components act in the process of carcinogenesis need to be clarified, mainly due to multifactorial etiology of the neoplasms. Pin-pointing of the role played in carcinogenesis by any single signaling pathway remains particularly difficult. The aim of this review is to summarize the current data of several epidemiological studies, experiments in vitro and on animal models, to increase our understanding of the complex role of IGF family components in the most common human cancers.

Tumor progression, metastasis, and modulators of epithelial-mesenchymal transition in endometrioid endometrial carcinoma: an update

Endometrioid endometrial carcinoma (EEC), also known as type 1 endometrial cancer (EC), accounts for over 70-80% of all cases that are usually associated with estrogen stimulation and often develops in a background of atypical endometrial hyperplasia. The increased incidence of EC is mainly confined to this type of cancer. Most EEC patients present at an early stage and generally have a favorable prognosis; however, up to 30% of EEC present as high risk tumors, which have invaded deep into the myometrium at diagnosis and progressively lead to local or extra pelvic metastasis. The poor survival of advanced EC is related to the lack of effective therapies, which can be attributed to poor understanding of the molecular mechanisms underlying the progression of disease toward invasion and metastasis. Multiple lines of evidence illustrate that epithelial-mesenchymal transition (EMT)-like events are central to tumor progression and malignant transformation, endowing the incipient cancer cell with invasive and metastatic properties. The aim of this review is to summarize the current knowledge on molecular events associated with EMT in progression, invasion, and metastasis of EEC. Further, the role of epigenetic modifications and microRNA regulation, tumor microenvironment, and microcystic elongated and fragmented glands like invasion pattern have been discussed. We believe this article may perhaps stimulate further research in this field that may aid in identifying high risk patients within this clinically challenging patient group and also lead to the recognition of novel targets for the prevention of metastasis - the most fatal consequence of endometrial carcinogenesis.

Exenatide inhibits the growth of endometrial cancer Ishikawa xenografts in nude mice

Studies have showed that diabetes is one of the high risk factors of endometrial cancer; however, no reports describe the anti- or pro-cancer effect of a new kind of anti-diabetes drug, glucagon-like peptide-1 receptor agonist exenatide (exendin-4), on endometrial cancer. To investigate whether exenatide promotes or inhibits the growth of endometrial cancer, we used the subcutaneous human endometrial cancer cell Ishikawa xenografts in nude mouse model, and divided them into control group and exenatide-treated group. The tumor growth rate in exenatide group was slower than that in control group, and the apoptosis rate of exenatide group was higher than that in control group. In vitro, exendin-4 also attenuated Ishikawa cell viability and clone formation rate, but promoted cell apoptosis. There was an increase of phosphorylated-AMPK protein, a decrease of phosphorylated-mTOR protein both in vivo and in vitro after exenatide or exendin-4 treatment. Moreover, when treated with exendin-4 plus AICAR, an AMPK activator, cell apoptosis increased with higher ratio of phosphorylayed-AMPK/AMPK, lower ratio of phosphorylated-mTOR/mTOR and higher expression of cleaved caspase-3 than those in exendin-4 alone group, and the results were the opposite when treated with exendin-4 plus compound C, an AMPK inhibitor. Our results suggest that exenatide could attenuate the growth of endometrial cancer Ishikawa xenografts in nude mice, and AMPK may be the target of the mechanism.

Role and mechanism of insulin-like growth factor 2 on the proliferation of human trophoblasts in vitro

AIM

To study the effect and relevant molecular mechanisms of insulin-like growth factor 2 (IGF2) on the proliferative activity of first trimester human trophoblasts in vitro.

MATERIALS AND METHODS

Extravillous cytotrophoblasts (EVCTs) were isolated and cultured. Cells were cultured with IGF2 at different concentrations and the proliferative activity was measured using methyl thiazolyl tretrazolium assay. LY294002, a specific inhibitor of the phosphatidylinositol 3-kinase (PI3K), was used as an indirect indicator of the possible involvement of the PI3K signal pathway. We tested the apoptosis rate using flow cytometry technology influenced by IGF2 with or without LY294002. The effects of IGF2 on phosphorylation of key cell signaling proteins (protein kinase B [AKT] and phosphorylated AKT) in EVCTs were examined by western blot analysis with or without LY294002.

RESULTS

There was a significant difference between the IGF2 group above 10 nM and the control group (P < 0.05). LY294002 (10 μM) not only inhibited the proliferative activity of EVCT, but also significantly restrained the effect on EVCTs (P < 0.05). In vitro data proved that the apoptosis rate decreased when IGF2 was added (P < 0.05), but increased when inhibited by LY294002 (P < 0.05). After incubation with IGF2, AKT phosphorylation increased compared to incubation without IGF2 treatment (P < 0.05). LY294002 activation reduced the IGF2-induced effects (P < 0.05).

CONCLUSIONS

Our data suggest that IGF2 enhances EVCT proliferation and inhibits apoptosis. The PI3K/AKT pathway is an important signaling pathway in the proliferative activity of EVCTs on early human pregnancy in vitro.

NEDD4 ubiquitin ligase is a putative oncogene in endometrial cancer that activates IGF-1R/PI3K/Akt signaling

OBJECTIVE

The PI3K/Akt pathway is frequently dysregulated in endometrial cancer, the most common gynecologic malignancy. Emerging evidence identifies the ubiquitin ligase NEDD4 as a key regulator of the PI3K/Akt pathway via activation of insulin-like growth factor-1 receptor (IGF-1R). Our objective was to understand the role of NEDD4 in endometrial cancer.

METHODS

NEDD4 expression was assessed by immunohistochemistry in a tissue microarray with 77 endometrial lesions ranging from normal benign endometrium to tumor specimens of varying stage and grade. Studies were extended to a panel of eight endometrial cancer cell lines phenotypically representing the most common endometrial patient tumors.

RESULTS

Immunohistochemistry demonstrated robust staining of NEDD4 in endometrial tumor specimens, with greater NEDD4 expression in the most aggressive tumors. Expression of NEDD4 was detected in a majority of endometrial cancer cell lines surveyed. Exogenous overexpression of murine Nedd4 in endometrial cancer cell lines with modest endogenous NEDD4 expression resulted in a significant increase in the rate of proliferation. Nedd4 overexpression also promoted an increase in cell surface localization of IGF-1R and activation of Akt. Inhibition of PI3K/Akt signaling reversed the enhanced cell growth in Nedd4-overexpressing endometrial cancer cells. In addition, the expression of NEDD4 in endometrial tumors positively correlated with the Akt downstream effector FoxM1.

CONCLUSIONS

This study identifies NEDD4 as a putative oncogene in endometrial cancer that may augment activation of the IGF-1R/PI3K/Akt signaling pathway.

Proliferative and signaling activities of insulin analogues in endometrial cancer cells

Insulin analogues have been developed to achieve further improvement in the therapy of diabetes. However, modifications introduced into the insulin molecule may enhance their affinity for the insulin-like growth factor-1 receptor (IGF1R). Hyperinsulinemia has been identified as a risk factor for endometrial cancer. We hypothesized that insulin analogues may elicit atypical proliferative and signaling activities in endometrial cancer cells. Our results demonstrate that glargine, but not detemir, stimulated cell proliferation, displayed an anti-apoptotic effect, and had a positive effect on cell cycle progression in endometrial cancer cell lines ECC-1 and USPC-1. In addition, we showed that glargine and detemir induced dual activation of the insulin receptor (INSR) and IGF1R in both cell types. Furthermore, we showed that glargine elicited signaling events that are markedly different from those induced by insulin. In conclusion, our data support the concept that, although insulin analogues were designed to display insulin-like metabolic effects, glargine and, possibly, additional analogues exhibit IGF1-like activities and, accordingly, may function as IGF1 analogues.

Functional characterization of GH-like homolog in amphioxus reveals an ancient origin of GH/GH receptor system

Amphioxus belongs to the subphylum cephalochordata, an extant representative of the most basal chordates. Despite many studies on the endocrine system of amphioxus, no evidence showed the presence of pituitary hormones. In this study, we clearly demonstrated the existence of a functional GH-like hormone in amphioxus, which is able to bind purified GH receptors, stimulate IGF-I expression, promote growth rate of fish, and rescue embryonic defects caused by a shortage of GH. We also showed the presence of a GH/prolactin-like-binding protein containing the entire hormone binding domain of GH/prolactin receptors in amphioxus, which is widely expressed among tissues, and interacts with the GH-like hormone. It is clear from these results that the GH/GH receptor-like system is present in amphioxus and, hence, in all classes of chordates. Notably, the GH-like hormone appears to be the only member of the vertebrate pituitary hormones family in amphioxus, suggesting that the hormone is the ancestral peptide that originated first in the molecular evolution of the pituitary hormones family in chordates. These data collectively suggest that a vertebrate-like neuroendocrine axis setting has already emerged in amphioxus, which lays a foundation for subsequent formation of hypothalamic-pituitary system in vertebrates.

Regulation of insulin-like growth factor signaling by metformin in endometrial cancer cells

Obesity, diabetes and insulin resistance are marked risk factors that promote the development of type I endometrial cancer. Previous studies have demonstrated that insulin-like growth factor 1 (IGF-1) and IGF-2 promote cell proliferation in endometrial cancer cells, while metformin reverses this effect and inhibits cell proliferation. However, the effects of metformin on the regulation of the IGF signaling pathway are unclear. The aim of this study was to investigate the regulation of IGF signaling by metformin in endometrial cancer cells, and to determine the effects of metformin combined with IGF-1 receptor (IGF-1R) inhibitor on cell proliferation and apoptosis. Cell proliferation was assessed following exposure of Ishikawa and HEC-1B endometrial cancer cell lines to metformin and/or the IGF-1R inhibitor, PPP. Apoptosis was assessed by TdT-mediated dUTP nick end labeling assay. Metformin was observed to downregulate IGF-1R and upregulate IGF binding protein-1 (IGFBP-1) mRNA and protein expression, while compound C, an adenosine monophosphate protein kinase inhibitor, reversed this effect. Metformin administered with PPP inhibited endometrial cancer cell proliferation to a greater degree than treatment with either agent alone. At high concentrations (1 or 2 mM), metformin induced apoptosis in endometrial cancer cells. Metformin combined with IGF-1R axis inhibitors may act synergistically to kill tumor cells, as metformin was shown to delay and prevent IGF-1R feedback. In conclusion, this study supported the results of animal studies and subclinical studies, demonstrating the feasibility of metformin combined with IGF-1R axis inhibitors in the treatment of endometrial cancer.

Expression Profiles of the Insulin-like Growth Factor System Components in Liver Tissue during Embryonic and Postnatal Growth of Erhualian and Yorkshire Reciprocal Cross F1 Pigs

In Erhualian and Yorkshire reciprocal cross F1 pig populations, we examined the mRNA expression characteristic of liver-derived IGF-1, IGF-1R, IGF-2, IGF-2R and IGFBP-3 during the embryonic and postnatal developmental periods (E50, E70, E90, D1, D20, D70, D120 and D180). Our results demonstrated that the IGF-system genes mRNA levels exhibited an ontogenetic expression pattern, which was potentially associated with the porcine embryonic development, postnatal growth, organogenesis and even the initiation and acceleration of puberty. The expression pattern of IGF-system genes showed variation in the reciprocal cross (F1 YE and EY pigs). This study also involved the expression features of imprinted genes IGF-2 and IGF-2R. The parent-of-origin effect of imprinted genes was reflected by their differential expression between the reciprocal crosses populations. The correlation analysis also indicated that the regulatory network and mechanisms involved in the IGF system were a complex issue that needs to be more fully explored. A better understanding of IGF system components and their interactive mechanisms will enable researchers to gain insights not only into animal organogenesis but also into somatic growth development and even reproduction.

IGF1R tyrosine kinase inhibitor enhances the cytotoxic effect of methyl jasmonate in endometrial cancer

The present study evaluated the cytotoxic activity of methyl jasmonate (MJ) in endometrial cancer cells and examined the hypothesis that the apoptotic and anti-proliferative actions of MJ in these cell lines can be enhanced by co-targeting the insulin-like growth factor-1 receptor (IGF1R) signaling pathway. MJ had a potent pro-apoptotic effect and exhibited significant toxicity in all cell lines tested. MJ in combination with NVP-AEW541, a selective IGF1R tyrosine kinase inhibitor, had significantly increased cytotoxicity. MJ decreased IGF1R phosphorylation, however, it enhanced AKT phosphorylation and abolished the anti-apoptotic effect of IGF1. These findings suggest that combined IGF1R inhibitor and MJ administration may constitute an attractive modality for treating endometrial cancer.

The IGF Hormonal Network in Endometrial Cancer: Functions, Regulation, and Targeting Approaches

Epidemiological as well as clinical and experimental data identified the insulin-like growth factors (IGF1, IGF2) as important players in gynecological cancers in general, and endometrial tumors in particular. The IGF1 receptor (IGF1R), which mediates the proliferative and anti-apoptotic activities of both ligands, emerged in recent years as a promising therapeutic target in oncology. However, most clinical trials conducted so far led to mixed results, emphasizing the need to identify biomarkers that can predict responsiveness to anti-IGF1R-targeted therapies. This article will review recent data regarding the role and expression of IGF system components in endometrial cancer. In addition, we will review data on the interplay between the IGF signaling pathway and tumor suppressors p53 and breast cancer susceptibility gene-1 (BRCA1). Anti-oncogenes p53 and BRCA1 play a key role in the etiology of gynecological cancers and, therefore, their interaction with IGF1R is of high relevance in translational terms. A better understanding of the complex mechanisms underlying the regulation of the IGF system will improve our ability to develop effective treatment modalities for endometrial tumors.

IGF1R-directed targeted therapy enhances the cytotoxic effect of chemotherapy in endometrial cancer

This study evaluated the potential ability of MK-0646 to inhibit IGF1-mediated biological actions and cell signaling events in Type 1 and Type 2 endometrial cancer. We found that MK-0646 treatment significantly decreased IGF1R expression. In addition, pretreatment with MK-0646 decreased the IGF1-induced phosphorylation of IGF1R, AKT and ERK. Apoptosis analyses showed that MK-0646 abolished the anti-apoptotic effect of IGF1. Furthermore, MK-0646 treatment abolished the IGF1-stimulatory effect on proliferation and enhanced the cytotoxic effect of cisplatin. These findings indicate that specific inhibition of IGF1R could be a useful therapeutic approach for Type 1 and Type 2 endometrial cancer.

Targeting IGF-1 signaling pathways in gynecologic malignancies

INTRODUCTION

The signaling pathways of the insulin-like growth factors (IGF) have been implicated in the etiology of a number of epithelial neoplasms including prostate, breast, colon and more recently, gynecologic cancers. The insulin-like growth factor-1 receptor (IGF-1R) is expressed in most transformed cells, where it displays potent anti-apoptotic, cell-survival and potentially, transforming activities. IGF-1R expression and activation are typical hallmarks associated with tumor initiation and progression. Multiple approaches have been used to abrogate IGF-1R signaling for targeted cancer therapy including antibodies and small molecule tyrosine kinase inhibitors. These novel IGF-1R targeting agents have produced significant experimental and clinical results in many cancers and generated considerable optimism in the field of cancer therapy.

AREAS COVERED

The authors will review important research advances regarding the role of the IGF axis in cancer, particularly preclinical and clinical studies in cervical, uterine and ovarian cancers. The significance of tumor expression and circulating levels of the IGF pathway as well as targeting therapies of the IGF axis in the gynecologic cancers will be discussed.

EXPERT OPINION

Accumulating data confirm that the IGF-1R pathway has an important role in gynecologic cancers and in vivo and in vitro studies have shown a significant impact of IGF-1R targeted therapies in these malignancies, mainly ovarian and endometrial cancers. Currently, ongoing preclinical and clinical trials are evaluating the efficacy of IGF-1R targeting. A better understanding of the complex mechanisms underlying the regulation of the IGF system will improve the ability to develop effective treatment modalities for these malignancies.

Insulin-like growth factors in endometrioid adenocarcinoma: correlation with clinico-pathological features and estrogen receptor expression

Background

Endometrial carcinoma is a common malignancy of female genital tract. Insulin-like growth factor is known to elicit estrogen-induced mitogenic activity and anti-apoptotic effect in endometrial tissues.

Methods

The retrospective study investigated the expression of insulin-like growth factors, estrogen receptors and their associations in endometrioid adenocarcinoma (EAC) from 80 EAC patients in immunohistochemistry, and 58 EAC patients and 42 control patients in quantitative RT-PCR. The Pearson correlation analysis was used to analyze their correlations with clinic-pathological parameters.

Results

Our results showed that insulin-like growth factor-1 and insulin-like growth factor-2 mRNA levels were higher in tumor tissues and tumor-adjacent tissues than those in control cells, and were inversely correlated with the malignancy of the tumor with a positive correlation with ERα and ERβ expression. Insulin-like growth factor-1R protein expression was correlated with clinical stage, and insulin-like growth factor-2R protein expression was inversely correlated with histological grade.

Conclusions

Insulin-like growth factor system plays an important role in estrogen-induced endometrial carcinogenesis, and overexpression of insulin-like growth factor-1R in the advanced endometrioid adenocarcinoma is not estrogen-dependent.

AMG 479, a novel IGF-1-R antibody, inhibits endometrial cancer cell proliferation through disruption of the PI3K/Akt and MAPK pathways

Our goal was to evaluate the therapeutic potential of a novel antibody to the insulin growth factor-1 receptor (IGF-1-R; AMG 479) in endometrial cancer cells. The endometrial cancer cell lines, ECC-1/PRAB72 and RL-95-2, were used. Treatment with AMG 479 (0.02-200 nmol/L) resulted in inhibition of cell proliferation at 72 to 120 hours. Insulin growth factor-1 (0.15-7.5 nmol/L) stimulated growth in both cell lines (range of 15%-42%, P = .0025-.0445), which could be blocked by pretreatment with AMG 479 (mean of 29% for ECC-1/PRAB72, P = .006-.007; mean of 36% for RL-95-2, P = .0002-.0045). AMG 479 suppressed IGF-1-R kinase activity in a dose-dependent manner. Cells treated with AMG 479 underwent either G1 (ECC-1/PRAB72) or G2 (RL-95-2) arrest. AMG 479 decreased human telomerase reverse transcriptase (hTERT) mRNA expression in both endometrial cancer cell lines. Treatment with AMG 479 rapidly blocked IGF-1-induced phosphorylation of IFG-1-R, Akt, and p44/42. Thus, manipulation of the IGF-1-R pathway may serve as a promising therapeutic strategy for the treatment of endometrial cancer.

Laser capture microdissection with genome-wide expression profiling displayed gene expression signatures in endometrioid endometrial cancer

This research determined genes contributing to the pathogenesis of endometrioid endometrial cancer (EEC). Eight pairs of microdissected EEC samples matched with normal glandular epithelium were analyzed using microarray. Unsupervised analysis identified 162 transcripts (58 up- and 104 down-regulated) that were differentially expressed (p < .01, fold change ≥ 1.5) between both groups. Quantitative real-time polymerase chain reaction (qPCR) validated the genes of interest: SLC7A5, SATB1, H19, and ZAK (p < .05). Pathway analysis revealed genes involved in acid amino transport, translation, and chromatin remodeling (p < .05). Laser capture microdissection (LCM) followed by microarray enabled precise assessment of homogeneous cell population and identified putative genes for endometrial carcinogenesis.

R1507, an anti-insulin-like growth factor-1 receptor (IGF-1R) antibody, and EWS/FLI-1 siRNA in Ewing's sarcoma: convergence at the IGF/IGFR/Akt axis

A subset of patients with Ewing's sarcoma responds to anti-insulin-like growth factor-1 receptor (IGF-1R) antibodies. Mechanisms of sensitivity and resistance are unknown. We investigated whether an anti-IGF-1R antibody acts via a pathway that could also be suppressed by small interfering (si) RNA against the EWS/FLI-1 fusion protein, the hallmark of Ewing's sarcoma. The growth of two Ewing's sarcoma cell lines (TC-32 and TC-71) was inhibited by the fully human anti-IGF-1R antibody, R1507 (clonogenic and MTT assays). TC-32 and TC-71 cells express high levels of IGF-2, while RD-ES and A4573 Ewing's cell lines, which were less responsive to R1507 in our assays, express low or undetectable IGF-2, respectively. TC-71 cells also expressed high levels of IGF-1R, and R1507 decreased steady-state levels of this receptor by internalization/degradation, an effect which was associated with a decrease in p-IGF-1R, p-IRS-1, and p-Akt. EWS/FLI-1 siRNA also decreased p-Akt, due to its ability to increase IGF-BP3 levels and subsequently decrease IGF-1 and IGF-2 levels, thus inhibiting signaling through p-IGF-1R. This inhibition correlated with growth suppression and apoptosis. The attenuation of Akt activation was confirmed in TC-71 and HEK-293 (human embryonic kidney) cells by transfecting them with IGF-1R siRNA. We conclude that antibodies and siRNA to IGF-1R, as well as siRNA to EWS/FLI-1, act via intersecting IGF/IGF-1R signals that suppress a common point in this pathway, namely the phosphorylation of Akt.

Insulin-like growth factor-I receptor inhibition by specific tyrosine kinase inhibitor NVP-AEW541 in endometrioid and serous papillary endometrial cancer cell lines

PURPOSE

The role of the insulin-like growth factor (IGF) system in endometrial cancer has been well established. The IGF-I receptor (IGF-IR) emerged as a promising therapeutic target in a number of cancers. NVP-AEW541 (Novartis Pharma) is a pyrrolo(2,3-d)pyrimidine derivative with specific IGF-IR tyrosine kinase inhibitory activity. NVP-AEW541 has been shown to abrogate IGF-I-mediated IGF-IR autophosphorylation and to reduce activation of the IGF-IR signaling pathways. The aim of the present study was to investigate the anti-proliferative activity of NVP-AEW541 in Type I (endometrioid) and Type II (uterine serous papillary endometrial carcinoma, USPC) endometrial cancer cell lines.

METHODS

Type I (ECC-1, Ishikawa) and Type II (USPC-1, USPC-2) endometrial cancer cell lines were treated with NVP-AEW541 in the presence of IGF-I, and the following parameters were measured: IGF-IR, AKT and ERK phosphorylation, apoptosis, proliferation, cell cycle progression and IGF-IR internalization.

RESULTS

Results obtained showed that NVP-AEW541 abolished the IGF-I stimulated IGF-IR phosphorylation in all of the cell lines investigated, whereas it abolished AKT and ERK phosphorylation preferentially in ECC-1 and USPC-1 cells. Furthermore, the inhibitor prevented from IGF-I from exerting its antiapoptotic effect in ECC-1, USPC-1 and USPC-2 cells. In addition, proliferation assays showed that NVP-AEW541 caused a decrease in proliferation rate in all of the cell lines. NVP-AEW541 had no major effect on the insulin receptor.

CONCLUSION

Our results suggest that specific IGF-IR inhibition by NVP-AEW541 might be a promising therapeutic tool in endometrial cancer.

Insulin receptor substrate-2 gene polymorphism: is it associated with endometrial cancer?

OBJECTIVE

The G1057D polymorphism in the insulin receptor substrate-2 (IRS-2) gene has been reported to be associated with insulin resistance, obesity and type 2 diabetes. However little is known about its possible association with cancer. To investigate this association, we determined the distribution of its genotypes and frequency of alleles in endometrial cancer patients.

METHODS

The study population consisted of 184 subjects: 44 patients with endometrial cancer and 140 controls without cancer. All the patients were primarily treated with surgical intervention. DNA was extracted from the leucocytes by high pure polymerase chain reaction (PCR) template preparation kit. Genetic polymorphism of IRS-2 G1057D was detected by using PCR-based restriction fragment-length polymorphism.

RESULTS

For IRS-2 G1057D polymorphism, there was a significant difference in genotype distribution and allele frequency between endometrial cancer patients and controls (p < 0.001). The risk for endometrial cancer was 4.87 times higher in the individuals with the IRS-2 DD genotype compared to the GG genotype [95% confidence interval (CI): 1.74-13.63 p = 0.003]. Also individuals with the IRS-2 D allele had a significantly higher risk of endometrium cancer compared with individuals with the IRS-2 G allele, with a relative risk of 2.23 (95% CI: 1.36-3.67, p = 0.001) for cases compared with population controls.

CONCLUSION

These results suggest that IRS-2 G1057D polymorphism may be associated with endometrial cancer.

Targeting the IGF1 axis in cancer proliferation

The IGF network of ligands, cell-surface receptors and IGF-binding proteins has important roles at multiple levels, including the cellular, organ and organism levels. The IGF system mediates growth, differentiation and developmental processes, and is also involved in various metabolic activities. Dysregulation of IGF system expression and action is linked to diverse pathologies, ranging from growth deficits to cancer development. Targeting of the IGF axis emerged in recent years as a promising therapeutic approach in conditions in which the IGF system is involved. Specific IGF1 receptor (IGF1R) targeting, in particular, produced the best experimental and clinical results so far, and generated significant optimism in the field. This review provides a basic analysis of the role of the IGF1R in cancer biology and explores the functional interactions between the IGF signaling pathways and various cancer genes (e.g., oncogenes, tumor suppressors). In addition, we review a number of specific malignancies in which the IGF system is involved and summarize recent data on preclinical and clinical studies employing IGF1R-targeted modalities.

Head and neck squamous cancer stromal fibroblasts produce growth factors influencing phenotype of normal human keratinocytes

Epithelial-mesenchymal interaction between stromal fibroblasts and cancer cells influences the functional properties of tumor epithelium, including the tumor progression and spread. We compared fibroblasts prepared from stroma of squamous cell carcinoma and normal dermal fibroblasts concerning their biological activity toward normal keratinocytes assessed by immunocytochemistry and profiling of gene activation for growth factors/cytokines by microarray chip technology. IGF-2 and BMP-4 were determined as candidate factors responsible for tumor-associated fibroblast activity that influences normal epithelia. This effect was confirmed by addition of recombinant IGF-2 and BMP4, respectively, to the culture medium. This hypothesis was also verified by inhibition experiments where blocking antibodies were employed in the medium conditioned by cancer-associated fibroblast. Presence of these growth factors was also detected in tumor samples.

Mannose-6-phosphate/insulin-like growth factor 2 receptor (M6P/IGF2R) in carcinogenesis

The cation-independent mannose-6-phosphate/insulin-like growth factor 2 receptor (M6P/IGF2R) is a multifunctional receptor. It is involved in a variety of cellular processes which become dysregulated in cancer. Its tumor suppressor role was recognized a long time ago. However, due to its multifunctionality, it is not easy to understand the extent of its relevance to normal cellular physiology. Accordingly, it is even more difficult understanding its role in carcinogenesis. This review presents critical and focused highlights of data relating to M6P/IGF2R, obtained during more than 25 years of cancer research.

Evidence-based and potential benefits of metformin in the polycystic ovary syndrome: a comprehensive review

Metformin is an insulin sensitizer widely used for the treatment of patients affected by type 2 diabetes mellitus. Because many women with polycystic ovary syndrome (PCOS) are insulin resistant, metformin was introduced in clinical practice to treat these patients also. Moreover, metformin's effect has other targets beside its insulin-sensitizing action. The present review was aimed at describing all evidence-based and potential uses of metformin in PCOS patients. In particular, we will analyze the uses of metformin not only for the treatment of all PCOS-related disturbances such as menstrual disorders, anovulatory infertility, increased abortion, or complicated pregnancy risk, hyperandrogenism, endometrial, metabolic and cardiovascular abnormalities, but also for the prevention of the syndrome.