Insulin-like growth factors (IGF) are polypeptide hormones with potent anabolic and mitogenic effects that regulate cell growth and differentiation. Dysregulation of the IGF axis has been well documented in the development and progression of multiple types of cancer. As a result, compounds targeting the IGF axis have become an area of intense preclinical and clinical research for cancer therapeutics. The IGF axis is intimately involved with the insulin-signaling pathway because of their close homologies. This homology may explain hurdles encountered in the clinical development of IGF-targeted therapies, such as less-than-expected antitumor efficacy that may arise from compensatory increases in the activity of insulin receptor isoform A (IR-A), in response to IGF-I receptor (IGF-IR) inhibition and perturbations in glucose homeostasis, arising from the inhibition of insulin receptor isoform B (IR-B) activity. In this brief review, we compare differentiating factors that characterize the 3 major classes of IGF-targeting compounds: therapeutic antibodies that target IGF-IR, small molecule tyrosine kinase inhibitors that inhibit kinase activities of IGF-IR and IR, and antibodies that target IGF ligands. Cancer Res; 72(1); 3-12. Ó2012 AACR.

Insulin-like growth factors (IGF), IGF-I and IGF-II, are small polypeptides involved in regulating cell proliferation, survival, differentiation, and transformation.

PurposeInsulin-like growth factor (IGF) signaling through human insulin receptor isoform A (IR-A) contributes to tumorigenesis and intrinsic resistance to anti-IGF1R therapy. In the present study, we (a) developed quantitative TaqMan real time-PCR-based assays (qRT-PCR) to measure human insulin receptor isoforms with high specificity, (b) evaluated isoform expression levels in molecularly-defined breast cancer subtypes, and (c) identified the IR-A:IR-B mRNA ratio as a potential biomarker guiding patient stratification for anti-IGF therapies.Experimental DesignmRNA expression levels of IR-A and IR-B were measured in 42 primary breast cancers and 19 matched adjacent normal tissues with TaqMan qRT-PCR assays. The results were further confirmed in 165 breast cancers. The tumor samples were profiled using whole genome microarrays and subsequently subtyped using the PAM50 breast cancer gene signature. The relationship between the IR-A:IR-B ratio and cancer subtype, as well as markers of proliferation were characterized.ResultsThe mRNA expression levels of IR-A in the breast tumors were similar to those observed in the adjacent normal tissues, while the mRNA levels of IR-B were significantly decreased in tumors. The IR-A:IR-B ratio was significantly higher in luminal B breast cancer than in luminal A. Strong concordance between the IR-A:IR-B ratio and the composite Oncotype DX proliferation score was observed for stratifying the latter two breast cancer subtypes.ConclusionsThe reduction in IR-B expression is the key to the altered IR-A:IR-B ratio observed in breast cancer. The IR-A:IR-B ratio may have biomarker utility in guiding a patient stratification strategy for an anti-IGF therapeutic.

Background In pediatric tumor xenograft models, tumor-derived IGF-2 results in intrinsic resistance to IGF-1R-targeted antibodies, maintaining continued tumor angiogenesis. We evaluated the anti-angiogenic activity of a ligand-binding antibody (MEDI-573) alone or in combination with IGF-1 receptor binding antibodies (MAB391, CP01-B02). Methods IGF-stimulated signaling was monitored by increased Akt phosphorylation in sarcoma and human umbilical chord vascular endothelial cells (HUVECs). Angiogenesis was determined in vitro using capillary tube formation in HUVECs and in vivo using a VEGF-stimulated Matrigel assay. Tumor growth delay was examined in four sarcoma xenograft models Results The IGF-ligand binding antibody MEDI-573 suppressed Akt phosphorylation induced by exogenous IGF-1 and IGF-2 in sarcoma cells. Receptor binding antibodies suppressed IGF-1 stimulation of Akt phosphorylation, but IGF-2 circumvented this effect and maintained HUVEC tube formation. MEDI-573 inhibited HUVEC proliferation and tube formation in vitro, but did not inhibit angiogenesis in vivo, probably because MEDI-573 binds murine IGF-1 with low affinity. However, in vitro the anti-angiogenic activity of MEDI-573 was also circumvented by human recombinant IGF-1. The combination of receptor- and ligand-binding antibodies completely suppressed VEGF-stimulated proliferation of HUVECs in the presence of IGF-1 and IGF-2, prevented ligand-induced phosphorylation of IGF-1R/IR receptors, and suppressed VEGF/IGF-2 driven angiogenesis in vivo. The combination of CP1-BO2 plus MEDI-573 was significantly superior to therapy with either antibody alone against IGF-1 and IGF-2 secreting pediatric sarcoma xenograft models. Conclusions These results suggest that combination of antibodies targeting IGF receptor and ligands may be an effective therapeutic strategy to block angiogenesis for IGF-driven tumors.

The purpose of this study was to evaluate the association of expression level of α5β1-integrin and MMP-14 with clinicopathologic features and prognosis in colorectal cancer (CRC). The expressions of α5β1-integrin and MMP-14 in normal colorectal mucosa and CRC tissue were detected with immunohistochemistry. We estimated the five-year survival rate by the Kaplan-Meier method. The positive expressions rates of α5β1-integrin and MMP-14 in CRC tissue were 60.6% and 63.3% respectively, and there were significant differences on their positive expression rates between in CRC tissue and in normal colorectal mucosa(P<0.05). The expression rates of α5β1-integrin and MMP-14 in patients with poor histological differentiation, lymph node metastasis and high clinical staging were heightened. There was a significant difference (P<0.05) on the five-year survival rate for α5β1-integrin expression, which was 44.6% in positive groups and 75.5% in negative groups. And there was a significant difference (P<0.05) on the five-year survival rate for MMP-14 expression, which was 48.2% in positive group and 73.1% in negative group. The expression of α5β1-integrin and MMP-14 is correlated with the progression and metastasis of CRC, and α5β1-integrin and MMP-14 may be used as prognostic markers in CRC.Key words: CRC, immunohistochemistry, prognosis, survival CRC is the third most common cancer worldwide [1]. CRC is a cause of significant morbidity and cancer-related mortality in China both men and women. More than 17 million new cases of CRC were reported every year in China mainland. Despite recent treatment options and prognosis for patients with advanced CRC have improved through the development of novel drugs, progress in the treatment of CRC has been limited [2,3]. Most newly diagnosed patients will present with incurable disease, and have a median survival of less than 1 year. If metastasis has occurred, patient five-year survival rate after surgery falls dramatically from 90% to less than 10% [4]. It is, therefore, important to increase our understanding of the molecular changes leading to development, spread and metastasis of CRC and to identify potentially prognostic and predictive biomarkers for the disease.The conspicuous characteristic of malignant tumor is invasion and metastasis. To date, it is now clear that adhesive interaction play a critical role in the process of metastatic tumor dissemination [5].Cell adhesion molecules (CAMs) are involved in cell-cell and cell-extracellular matrix(ECM) binding, a highly complex process [6]. Integrins are the major adhesive molecules in cells and have been associated with metastasis of cancer cells. The integrins , a superfamily of heterodimer cell surface glycoprotein receptors composed of distinct α and β subunits [7], were originally described as cell adhesion receptors, but their functions in cell behavior including motility and invasion and their interactions with classical growth factor receptor signaling pathways have been increasingly recognized in the past few years [8]. Inte...

Background. Several childhood sarcomas, exhibit autocrine or paracrine growth through secretion of insulin-like growth factors 1 and 2 (IGF-1, IGF-2) and signaling through the Type 1 receptor (IGF-1R). In some childhood sarcoma xenografts IGF-1R antibodies dramatically decrease VEGF transcription and have potential anti-angiogenic activity. However, tumor-derived IGF-2 results in intrinsic resistance to IGF-1R-targeted antibodies, and continued tumor angiogenesis. We evaluated the anti-angiogenic activity of a ligand-binding antibody (MEDI-573) alone or in combination with IGF-1 receptor-binding antibodies as a potential strategy for effectively suppressing angiogenesis in pediatric sarcomas. Methods. IGF-stimulated signaling was monitored by increased Akt phosphorylation in sarcoma and human vascular endothelial (HUVEC) cells. Effects on angiogenesis were determined in vitro by capillary tube formation in HUVECs and in vivo using a VEGF-stimulated Matrigel assay followed by assay of hemoglobin and CD34 immunostaining. Results. The IGF-ligand binding antibody MEDI-573 suppressed Akt phosphorylation induced by exogenous IGF-1 and IGF-2 in sarcoma cells. Receptor binding antibodies, MAB391 and CP1-B02, suppressed IGF-1-stimulated phosphorylation of Akt, but not that induced by IGF-2. Both receptor-binding antibodies suppressed VEGF-induced HUVEC tube formation in vitro, but this was abrogated by exogenous IGF-2. MEDI-573 inhibited VEGF-stimulated HUVEC proliferation and tube formation in vitro, but did not inhibit angiogenesis in vivo, probably because MEDI-573 binds murine IGF-1 with low affinity. However, in vitro the anti-angiogenic activity of MEDI-573 was also circumvented by human recombinant IGF-1. The combination of receptor-binding and ligand-binding antibodies completely suppressed VEGF-stimulated proliferation of vascular endothelial cells in the presence of IGF-1 and IGF-2, and prevented ligand-induced phosphorylation of IGF-1R/IR receptors. Further, combining receptor-binding and ligand-binding antibodies completely suppressed VEGF-driven angiogenesis in a mouse model where Matrigel plugs containing both IGF-1 and IGF-2 were incorporated with VEGF. Conclusions. Our previous study showed that IGF-2 produced by tumor cells in the microenvironment could circumvent the anti-angiogenic effects of IGF-1 receptor binding antibodies. In contrast, IGF-1 was able to overcome the anti-angiogenic effect of the IGF-ligand binding antibody, MEDI-573. Our current study demonstrates that combining receptor and ligand binding antibodies effectively suppresses VEGF-stimulated angiogenesis in vitro and in a mouse model. Studies are ongoing to evaluate this therapeutic strategy using pediatric sarcoma xenograft models with characterized IGF expression. (Supported by grants CA77776, CA23099 and MedImmune). Citation Format: Hemant K. Bid, Cheryl A. London, Jin Gao, Haihong Zhong, Robert H. Hollingsworth, Peter J. Houghton. Dual targeting of the type 1 insulin-like growth factor receptor and its ligands as an effective anti-angiogenic strategy. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 5083. doi:10.1158/1538-7445.AM2013-5083

Insulin-like growth factors (IGF), IGF-I and IGF-II, are small polypeptides involved in regulating cell proliferation, survival, differentiation and transformation. IGF activities are mediated through binding and activation of IGF-1R or insulin receptor isoform A (IR-A). Overexpression of IGF-II and IR-A has been reported in multiple types of cancer, and has also been proposed as a potential mechanism for cancer cells to develop resistance to IGF-1R targeting therapy. MEDI-573 is a dual targeting human antibody that neutralizes both IGF-I and IGF-II. We have shown previously that this antibody inhibits IGF-1R activation by IGF and demonstrated potent in vivo tumor growth inhibition activity in IGF driven xenograft models. Here we show that MEDI-573 inhibits IGF-II activated IR-A signal pathways without cross reactivity to insulin, and therefore has minimum impact on glucose metabolism, which is mediated mainly by insulin/IR interaction. MEDI-573 blocks the binding of IGF-II to, and inhibits the subsequent phosphorylation of IR-A and IRS-1. MEDI-573 inhibited IGF-II-induced in vitro growth of IR-A overexpressing cells with or without the presence of up to 10uIU of insulin in the medium. In addition, MEDI-573 inhibited IGF-II-induced proliferation of IR-A-overexpressing cells as effectively as it inhibited the IGF-1R-overexpressing cells. The anti-proliferative activity of MEDI-573 is not changed across heterogeneous mixed cell populations with various ratios of IR-A- versus IGF-1R-expressing cells. In contrast, an IGF-1R specific antibody was most active at inhibiting the proliferation of a pure IGF-1R expressing homogenous population, but lost activity when the heterogeneous cell population contained increasing percentages (25-50%) of IR-A-expressing cells. We also examined the relative abundance of IR-A versus IR-B (insulin receptor isoform B) mRNA in multiple cancer cell lines using a previously published quantitative RT-PCR method. The results show that IR-A is frequently the dominant isoform overexpressed in these cancer cells. Taken together, these results demonstrate that by neutralizing IGF-I and IGF-II ligands, MEDI-573 is a dual targeting antibody that offers an effective approach to selectively target both the IGF-1R and IR-A signaling pathways and potentially overcome IGF-1R targeting resistance. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1757. doi:10.1158/1538-7445.AM2011-1757

Purpose: To analyze the relationship between the prognosis of patients with larynx squamous cell carcinoma (LSCC) and human papillomavirus (HPV) infection, p16 and p53 protein expression. Methods: All patients were treated at the department of radiation oncology, Anhui provincial hospital, between May 2005 and May 2012. The 41 consecutive patients with LSCC were treated surgically and received postoperative radiotherapy. Analyses of pathology specimen were surgically removed and performed on formalin-fixed, paraffin-embedded tissue samples. HPV DNA sequences in tumor tissues were screened by a commercial Luminex technique for HPVs and HPV-specific PCR assays. P16 and p53 protein expression were detected by immunohistochemical staining. Overall survival(OS)and progression-free survival(PFS)for HPV-positive and HPV-negative patients, p16-positive and p16-negative patients, p53-positive and p53-negative patients were estimated by Kaplan-Meier analysis. Cox regression model was used for multivariate analysis. Results: HPV-DNA was detected in 4(9.7%)of all specimens. Among them, 3 were positive for HPV-56,1 for HPV-16. With the follow-up of 3-78 months(a median of 34 months),patients with HPV-positive tumors had better overall survival than patients with HPV-positive tumors(75% vs 61%, P>0.05). Multivariate analysis by Cox regression model showed that nodal status was independent prognostic factors for patients with LSCC(P<0.05). Conclusions: HPV status is not an independent prognostic factor. Nodal status was independent prognostic factors for patients with LSCC.