Publications (46) View all
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Article: IGFBP ratio confers resistance to IGF targeting and correlates with increased invasion and poor outcome in breast tumors.
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ABSTRACT: To improve the significance of insulin-like growth factor-binding protein 5 (IGFBP-5) as a prognostic and potentially predictive marker in patients with breast cancer. Increased IGFBP-5 expression was identified in MCF-7 cells resistant (MCF-7R4) to the IGF-1R/insulin receptor (InsR) inhibitor BMS-536924 and its role examined by targeted knockdown and overexpression in multiple experimental models. Protein expression of IGFBP-5 was measured by immunohistochemistry in a cohort of 76 patients with breast cancer to examine correlative associations with invasive tumor fraction and outcome. The use of a combined IGFBP-5/IGFBP-4 (BPR) expression ratio was applied to predict anti-IGF-1R/InsR response in a panel of breast cancer lines and outcome in multiple breast tumor cohorts. IGFBP-5 knockdown decreased BMS-536924 resistance in MCF-7R4 cells, whereas IGFBP-5 overexpression in MCF-7 cells conferred resistance. When compared with pathologically normal reduction mammoplasty tissue, IGFBP-5 expression levels were upregulated in both invasive and histologically normal adjacent breast cancer tissue. In both univariate and multivariate modeling, metastasis-free survival, recurrence free survival (RFS), and overall survival (OS) were significantly associated with high IGFBP-5 expression. Prognostic power of IGFBP-5 was further increased with the addition of IGFBP-4 where tumors were ranked based upon IGFBP-5/IGFBP-4 expression ratio (BPR). Multiple breast cancer cohorts confirm that BPR (high vs. low) was a strong predictor of RFS and OS. IGFBP-5 expression is a marker of poor outcome in patients with breast cancer. An IGFBP-5/IGFBP-4 expression ratio may serve as a surrogate biomarker of IGF pathway activation and predict sensitivity to anti-IGF-1R targeting.Clinical Cancer Research 03/2012; 18(6):1808-17. · 7.74 Impact Factor -
Article: Resistance pathways relevant to insulin-like growth factor-1 receptor-targeted therapy.
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ABSTRACT: The dysregulation of insulin-like growth factor (IGF) signaling has been implicated as a critical contributor to malignant transformation, proliferation, survival, migration and resistance to anticancer therapies. As a result, IGF signaling has become an attractive target for the development of novel anticancer agents, and a large number of compounds, including blocking antibodies and tyrosine kinase inhibitors targeting the key signaling kinase of the IGF system, the IGF-1 receptor (IGF-1R), are in preclinical and clinical development. Although most tumors express the IGF-1R, expression alone is unlikely to be sufficient for sensitivity to IGF-targeted treatment. An understanding of the IGF signaling system and its downstream effectors is important, as this information will allow appropriate molecular markers of sensitivity to be determined, thus providing the rationale for combining IGF-1R blockade with other therapies to overcome resistance. This review highlights some of the preclinical and early clinical data on determinants of sensitivity to IGF targeting in human cancers, and reviews the rationale for targeting other tyrosine kinases, such as the insulin receptor and members of the EGFR family, to overcome intrinsic resistance to targeted IGF-1R therapy.Current opinion in investigational drugs (London, England: 2000) 10/2009; 10(10):1032-40. · 3.31 Impact Factor -
Article: Safety, tolerability, and pharmacokinetics of the anti-IGF-1R monoclonal antibody figitumumab in patients with refractory adrenocortical carcinoma.
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ABSTRACT: Insulin-like growth factor 1 receptor signaling through upregulation of the stimulatory ligand IGF-II has been implicated in the pathogenesis of adrenocortical carcinoma. As there is a paucity of effective therapies, this dose expansion cohort of a phase 1 study was undertaken to determine the safety, tolerability, pharmacokinetics, and effects on endocrine markers of figitumumab in patients with adrenocortical carcinoma. Figitumumab was administered on day 1 of each 21-day cycle at the maximal feasible dose (20 mg/kg) to a cohort of patients with metastatic, refractory adrenocortical carcinoma. Serum glucose, insulin, and growth hormone were measured pre-study, at cycle 4 and study end. Pharmacokinetic evaluation was performed during cycles 1 and 4. Fourteen patients with adrenocortical carcinoma received 50 cycles of figitumumab at the 20 mg/kg. Treatment-related toxicities were generally mild and included hyperglycemia, nausea, fatigue, and anorexia. Single episodes of grade 4 hyperuricemia, proteinuria, and elevated gamma-glutamyltransferase were observed. Pharmacokinetics of figitumumab was comparable to patients with solid tumors other than adrenocortical carcinoma. Treatment with figitumumab increased serum insulin and growth hormone levels. Eight of 14 patients (57%) had stable disease. The side effect profile and pharmacokinetics of figitumumab were similar in patients with adrenocortical carcinoma in comparison to patients with other solid tumors. While hyperglycemia was the most common adverse event, no clear patterns predicting severity were observed. The majority of patients receiving protocol therapy with single agent figitumumab experienced stability of disease, warranting further evaluation.Cancer Chemotherapy and Pharmacology 09/2009; 65(4):765-73. · 2.83 Impact Factor -
Article: Cixutumumab.
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ABSTRACT: The IGF pathway plays a major role in cancer cell proliferation, survival and resistance to antineoplastic therapies in many human malignancies. As such, interference with this pathway is the target of many investigational pharmacologic agents. Cixutumumab, a monoclonal antibody to IGF-1R, utilizes this concept. In this review, we summarize preclinical, pharmacologic and early clinical data regarding this agent and discuss the impact this drug might have on the future treatment of human cancers.Expert Opinion on Investigational Drugs 08/2009; 18(7):1025-33. · 5.27 Impact Factor -
Article: The pathway ahead in melanoma trials.
Oncology (Williston Park, N.Y.) 06/2009; 23(6):496, 498, 500. · 1.03 Impact Factor
