Insulin, Igf-1, GH and Cancer – time to think.

Dr. Weeks’ Comments:  Some intriguing articles reflecting insulin’s relationship with cancer chemotherapy.

Indian J Cancer. 2009 Oct-Dec;46(4):274-87.

Chemotherapy in adult soft tissue sarcoma.

Jain A, Sajeevan KV, Babu KG, Lakshmaiah KC.

Department of Medical Oncology, Kidwai Memorial Institute of Oncology, Bangalore, India. ankitjaindm@gmail.com

Soft tissue sarcomas (STSs) are rare and histologically diverse neoplasms. Recent results of various meta-analyses and development of newer drugs have changed the medical management of soft tissue sarcoma. This review gives an outline of chemotherapy and the newer targeted therapies for the same. We have carried out an extensive search in PubMed, Medline for almost all relevant articles concerning chemotherapy of soft tissue sarcoma. The available data from the literature is mainly composed of the most recent reviews, meta-analyses, phase II, and randomized phase III trials published in various peer reviewed journals and various international conferences. The role of neoadjuvant and adjuvant chemotherapy has been found to be controversial. The recent meta-analysis for adjuvant therapy in STSs has shown an increase in the overall survival with combination of ifosfamide and adriamycin. In locally advanced and metastatic STSs, single agent adriamycin remains the basic standard of medication. The combination of ifosfamide and adriamycin may also be used for rapid symptom relief and in patients planned for curative resection for metastases. Newer combinations of docetaxel and gemcitabine appear promising in selected subgroups, especially in leiomyosarcoma and malignant fibrous histiocytoma. Some recent developments include the European Union’s approval of trabectedin for advanced STSs patients who had progressed on adriamycin and ifosfamide therapy. The future of mTOR inhibitors, insulin like growth factor receptor inhibitors and anti-angiogenic drugs appear quite promising. Newer methodologies such as, Bayesian adaptive randomization and inclusion of newer end points like progression-free rate, time of progression rate, and tumor growth rate will improve the results of sarcoma trials. At the end of each section we have also presented recommendations from FNx01European Society of Medical Oncology and FNx08National Comprehensive Cancer Network guidelines v.1.2009 for better correlation with the present literature.

Curr Oncol Rep. 2009 Nov;11(6):446-53.

Critical signaling pathways in bone sarcoma: candidates for therapeutic interventions.

Geryk-Hall M, Hughes DP.

Department of Pediatrics Research, Unit 853, Children’s Cancer Hospital, The University of Texas, M. D. Anderson Cancer Center, PO Box 301402, Houston, TX 77030, USA.

Bone sarcomas cause disproportionate morbidity and mortality and desperately need new therapies as there has been little improvement in outcomes in 20 years. Identification of critical signaling pathways, including type 1 insulin-like growth factor receptor (IGF-1R) for Ewing sarcoma and possibly osteosarcoma, and the ERBB and the Wnt signaling pathways for osteosarcoma, have emerged as receptors mediating vital signals for bone sarcoma. Akt, mammalian target of rapamycin (mTOR), phosphoinositide 3-kinases, mitogen-activated protein kinase kinase, extracellular signal-regulated kinases, and Ras pathway play key roles in at least some tumors, and inhibition of mTOR in particular will likely lead to improved survival, although clinical trials are still underway. The Notch pathway and ezrin are essential for osteosarcoma metastasis, and Fas downregulation is necessary for survival of metastases in lungs. As little is known about chondrosarcoma signaling, more preclinical work is needed. By defining vital signaling pathways in bone sarcomas, small molecule inhibitors can be applied rationally, leading to longer survival and reducing morbidity and late effects from intensive chemotherapy.

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Cancer. 2009 Nov 15;115(22):5243-50.

Correlation between clinical outcome and growth factor pathway expression in osteogenic sarcoma.

Abdeen A, Chou AJ, Healey JH, Khanna C, Osborne TS, Hewitt SM, Kim M, Wang D, Moody K, Gorlick R.

Department of Orthopaedic Surgery, Memorial Sloan-Kettering Cancer Center, Weill Medical College of Cornell University, New York, New York.

BACKGROUND:: Multiple cell-signaling ligands and receptors-including vascular endothelial growth factor (VEGF), insulin-like growth factor (IGF), endothelial growth factor (EGF), v-akt murine thymoma viral oncogene homolog (AKT), platelet-derived growth factor (PDGF), mitogen-activated protein kinase (MAPK), and 70-kilodalton (kD) protein S6 kinase (p70S6 kinase)-reportedly are variably expressed in osteogenic sarcoma. Expression of these proteins may have future implications for prognostication and targeted therapy. The objective of the current study was to determine the relation between clinical outcome and the expression of these proteins. METHODS:: A paraffin-embedded microarray of 48 human osteogenic sarcoma tissue specimens was stained with the antibodies against VEGF, IGF, EGF, AKT, PDGF, MAPK, and p70S6 kinase. Staining for each protein included the total protein and, when applicable, the phosphorylated version of the protein. Immunohistochemical staining was then correlated with patient survival (overall survival [OS] and event-free survival [EFS]), histologic response to chemotherapy, and serum markers.

RESULTS:: There was a negative correlation between VEGF receptor 3 (VEGF-R3) and both OS and EFS. VEGF-B was correlated with a poor histologic response to chemotherapy. Serum markers were not correlated with any specific proteins. When using a P value of .05, multiple correlations were observed between proteins of various pathways.

CONCLUSIONS: The current results suggested that the VEGF pathway is a critical signaling pathway in osteogenic sarcoma. These data have identified specific proteins within these pathways toward which future investigations should be directed to further clarify their prognostic potential. Cancer 2009. Published 2009 by the American Cancer Society.

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Curr Drug Targets. 2009 Oct;10(10):923-36.

Clinical development of inhibitors of the insulin-like growth factor receptor in oncology.

Gualberto A, Pollak M.

Pfizer Oncology, 50 Pequot Ave. MS6025-A3266, New London, CT 06320, USA. antonio.gualberto@pfizer.com

The insulin-like growth factor I receptor (IGF-IR) pathway plays a major role in cancer growth, tumor cell survival and resistance to therapy. Ancillary evidence that targeting the IGF-IR may be useful in the treatment of cancer has been accumulating for almost two decades. Today, more than two dozen compounds have been developed and clinical trials are underway for at least 12 of those. The ability to pharmacologically control the IGF-IR pathway holds not only promising therapeutic implications but also the possibility to gather a better understanding of the role of the IGF axis in tumor initiation and progression. This review focuses on the preclinical rationale for targeting the IGF-IR and other components of the IGF-I system, early clinical results observed to date, biomarker approaches employed and the lessons from these early results for future study design. Early clinical trials reveal an acceptable safety profile together with pharmacodynamic evidence of receptor targeting. Instances of single-agent activity during phase I evaluations have been well documented and a recently reported randomized phase II study indicates that co-administration of an anti-IGF-IR antibody with chemotherapy improves objective response rate and progression-free survival in non-small cell lung cancer patients. These early results support ongoing research across a broad range of cancer indications.

PMID: 19663769 [PubMed – in process]

J Clin Endocrinol Metab. 2009 Oct;94(10):3931-8. Epub 2009 Jul 21.

Growth hormone excess promotes breast cancer chemoresistance.

Zatelli MC, Minoia M, Molè D, Cason V, Tagliati F, Margutti A, Bondanelli M, Ambrosio MR, degli Uberti E.

Section of Endocrinology, Department of Biomedical Sciences and Advanced Therapies, University of Ferrara, 44100 Ferrara, Italy.

CONTEXT: GH and IGF-I are known to promote breast carcinogenesis. Even if breast cancer (BC) incidence is not increased in female acromegalic patients, mortality is greater as compared with general population. OBJECTIVE: The objective of the study was to evaluate whether GH/IGF-I excess might influence BC response to chemotherapy. DESIGN: We evaluated GH and IGF-I effects on cell proliferation of a BC cell line, MCF7 cells, in the presence of doxorubicin (Doxo), frequently used in BC chemotherapy, and the possible mechanisms involved.

RESULTS: GH and IGF-I induce MCF7 cell growth in serum-free conditions and protect the cells from the cytotoxic effects of Doxo. GH effects are direct and not mediated by IGF-I because they are apparent also in the presence of an IGF-I receptor blocking antibody and disappear in the presence of the GH antagonist pegvisomant. The expression of the MDR1 gene, involved in resistance to chemotherapeutic drugs, was not induced by GH. In addition, c-fos transduction was reduced by Doxo, which prevented GH stimulatory effects. Pegvisomant inhibited basal and GH-induced c-fos promoter transcriptional activity. Autocrine GH action is ruled out by the lack of endogenous GH expression in this MCF7 cell strain.

CONCLUSIONS: These data indicate that GH can directly induce resistance to chemotherapeutic drugs with a mechanism that might involve GH-induced early gene transcription and support the hypothesis that GH excess can hamper BC treatment, possibly resulting in an increased mortality.

Oncogene. 2009 Aug 27;28(34):3009-21. Epub 2009 Jul 6.

Emerging role of insulin-like growth factor receptor inhibitors in oncology: early clinical trial results and future directions.

Gualberto A, Pollak M.

Clinical Department, Pfizer Oncology, New London, CT, USA.

Preclinical evidence that targeting the insulin-like growth factor receptor (IGF-IR) is effective in cancer treatment has been accumulating for almost two decades. Efforts to develop drugs began in the late 1990s, and initial data from clinical trials were reported in 2006. The biological rationale for IGF-IR targeting has potential relevance to many tumor types, and early results have justified expanded programs to evaluate IGF-IR-targeting agents in many areas of clinical need. More than two dozen drug candidates have been developed and clinical trials are underway for at least 12 of these. Early clinical trials reveal an acceptable safety profile together with pharmacodynamic evidence that the receptor can be successfully targeted. It is premature to draw conclusions regarding efficacy, but well-documented instances of single-agent activity were noted during phase I evaluations, and recent evidence from a phase II study suggests that co-administration of an anti-IGF-IR antibody with chemotherapy for non-small-cell lung cancer improves objective response rate and progression-free survival. With more than 70 trials involving a variety of drug candidates underway, the IGF-IR is becoming one of the most intensively investigated molecular targets in oncology. Early results justify the continuation of ongoing research across a broad range of cancer indications.

Med Hypotheses. 2009 Oct;73(4):606-7. Epub 2009 Jun 27.

Is it the time for metformin to take place in adjuvant treatment of Her-2 positive breast cancer? Teaching new tricks to old dogs.

Yurekli BS, Karaca B, Cetinkalp S, Uslu R.

Division of Endocrinology and Metabolism, Ege University School of Medicine, 35100 Izmir, Turkey. bsareryurekli@yahoo.com

Breast cancer is the most common malignancy diagnosed among women. According to the new molecular subclassification, basal like and Her-2 positive breast cancers have the worst outcome and these are the ones in which chemotherapy is a must as a part of adjuvant treatment. New treatment options that could be used as an adjuvant maintenance treatment are still being investigated. Insulin hormone is one of the reasons of breast cancer recurrence and death in breast cancer survivors. Targeting insulin as a therapeutic modality in breast cancer could be an option in the adjuvant treatment of breast cancer. It seems that insulin may signal to activate a cascade of proliferative and anti-apoptotic events in the cancer cell. Metformin, an oral anti-diabetic known for 50 years, may also have direct effects on cancer cells. Metformin causes Her-2 suppression via the inhibition of mTOR in breast cancer cells. Thus, we believe that the time has arrived both to target insulin reduction and to alter Her-2 oncogene based molecular pathogenetic steps in breast cancer by using metformin as an adjuvant therapy in breast cancer patients.

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