- Metastasis: Human Breast Cancer to Bone
- S14 as a Therapeutic Target for Breast Cancer
- Chromosomal Instability (CIN) Signatures for Human Cancers
- ATM Variants are Breast Cancer Susceptibility Alleles
- VEGF121/rGel: Therapeutic agent targeting neovasculature of breast tumor
- Targeting Breast Cancer Vasculature with Homing Peptides
- Biomimetic Composite Scaffold for Breast Reconstruction Following Tumor Resection
- Evaluation of Hyperspectral Imaging as a Tool for Identifying Breast Cancer Tissue In-Situ
Metastasis, the formation of secondary tumors in organs distant from the primary tumor, is the leading cause of death from breast cancer and presents the most clinically challenging aspect of human breast cancer. Early intervention in the pathogenesis of bone metastasis is desirable because bone is the most frequent site of breast cancer metastasis. Dr. Danny R. Welch of the University of Alabama, Birmingham, is a recipient of a Fiscal Year 2001 Breast Cancer Research Program (BCRP) Idea Award to assess the role of metastasis suppressor genes in suppressing metastases to bone without affecting tumorigenicity of tumor cells. Previously, Dr. Welch had discovered two genes, KISS1 and BRMS1, that were shown to suppress human breast cancer metastasis to lung and lymph nodes in xenograft models without affecting tumorigenicity. A third gene identified by Dr. Welch, osteopontin, present in metastatic cells, exhibits properties that enhance bone colonization. With funding from the Department of Defense BCRP, the investigator's main objective was to elucidate the molecular mechanisms involved in bone metastasis. Knowing that BRMS1 suppresses metastasis from an orthotopic site to lung and regional nodes, Dr. Welch wondered whether metastasis would be suppressed at all sites by BRMS1 and KISS1. Dr. Welch's team developed two animal models (GFP-tagged MDA-MB-435 and MDA-MB-231) and demonstrated that tumor cells in these models enter the bone microenvironment and kill osteoblasts and, eventually, osteoclasts. Furthermore, the investigative team developed GFP-tagged BRMS1 and KISS1 gene-expressing cells and showed that BRMS1 and KISS1 suppress metastasis to bone as well as to all other organs in both models. Dr. Welch's team continues to explore osteopontin, deepening our understanding of breast cancer metastasis and moving the breast cancer field forward toward developing therapies that interfere with bone colonization.
Phadke PA, Mercer RR, Harms JF, et al. 2006. Kinetics of metastatic breast cancer cell trafficking in bone. Clinical Cancer Research 12:1431-1440.
Shevde LA, Samant RS, Paik JC, et al. 2006. Osteopontin knockdown suppresses tumorigenicity of human metastatic breast carcinoma. Clinical & Experimental Metastasis 23:123-133.
Samant RS, Debies MT, Hurst DR, et al. 2006. Suppression of murine mammary carcinoma metastasis by the murine ortholog of Breast Cancer Metastasis Suppressor 1 (Brms1). Cancer Letters 235:260-265.
DeWald DB, Torabinejad J, Samant RS, et al. 2005. Metastasis suppression by BRMS1 involves reduction of phosphoinositide signaling in MDA-MB-435 breast carcinoma cells. Cancer Research - Priority Report 65:713-717.
Koblinski JE, Kaplan-Singer B, VanOsdol S, et al. 2005. Endogenous osteonectin/SPARC/BM-40 expression inhibits MDA-MB-231 breast cancer cell metastasis. Cancer Research 65:7370-7377.
Dr. William Kinlaw of the Dartmouth Medical School received a Fiscal Year 2002 Breast Cancer Research Program Idea Award to determine the potential of S14 (Spot 14; THRSP), a nuclear protein overexpressed in breast cancer cells, as a therapeutic target. Breast cancer cells appear to develop dependence on this protein because it activates genes required for the synthesis of fatty acids that the tumor cells need to fuel their growth and survival. Dr. Kinlaw's main goal is to advance the potential of anti-S14 therapy for human breast cancer. The researchers performed structural studies using circular dichroism, nuclear magnetic resonance, and computer modeling to discern the structure of the S14 self interaction domain that is a potential anticancer target. The investigative team identified two siRNAs that knock down S14 protein in cultured breast cancer cells and found them to be cytotoxic. Importantly, they also found that breast cancer cells do not make the enzyme required for access to lipids from the bloodstream, although normal cells of the mammary fat pad do supply that enzyme for the breast microenvironment. This suggested that breast cancer cells are uniquely dependent on the expression of S14 for survival outside of the mammary gland. In other studies, the team has investigated the utility of using S14 expression in breast cancers as a clinical marker of adverse outcomes. To accomplish this, the team produced a monoclonal antibody to identify S14 in a series of breast cancers by immunohistochemistry. These studies revealed strong associations of S14 staining with invasive tumor size and grade, and a striking power to predict tumor recurrence. Taken together, Dr. Kinlaw's findings indicate that although S14 is not an oncogene per se, it plays a critical role in the metastatic process when cancer cells leave the metabolically supportive microenvironment of the mammary gland and must meet the challenge of supplying their own lipids for survival. S14 overexpression thus appears to be a driver of aggressiveness in breast cancer by providing cells with an enhanced lipid synthesizing capacity that helps ensure their survival during metastasis. As such, S14 merits strong consideration as a novel therapeutic target in this disease.
Wells WA, Schwartz GN, Morganelli PM, et al. 2006. Expression of "Spot 14" (THRSP) predicts diseases free survival of a new molecular marker. Breast Cancer Research and Treatment 98(2):231-240.
Martel PM, Bingham CM, McGraw CJ, et al. 2006. S14 protein in breast cancer cells: Direct evidence of regulation by SREBP-1c, superinduction with progestin, and effects on cell growth. Experimental Cell Research 312:278-288.
Kinlaw W, Quinn J, Wells W, et al. 2006. S14: A marker of aggressive breast cancer and a potential therapeutic target. Endocrinology 147(9):4048-4055.
Chromosomal Instability (CIN) Signatures for Human Cancers
Posted November 1, 2006
Dr. Lyndsay Harris, M.D., Yale University, New Haven, Connecticut, (formerly of the Dana-Farber Cancer Institute, Boston, Massachusetts)
Breast cancer cells exhibit a high frequency of aneuploidy (an abnormal number of chromosomes), which is a consequence of chromosomal instability (CIN). Because an aneuploidy increase is positively correlated with the transition from premalignant to metastatic cancer, Dr. Lyndsay Harris of the Dana-Farber Cancer Institute is searching for the cause of this particular form of CIN, an investigation that is critical to an understanding of breast cancer genesis and devising possible clinical treatments. With funding from a Department of Defense Breast Cancer Research Program Fiscal Year 2003 Clinical Translational Research Award, Dr. Harris is creating computational tools and methods to characterize aneuploidy in tumor samples based on coordinated aberrations in gene expression localized to each chromosomal region. Her work thus far has led to the identification of a CIN signature whose net overexpression was predictive of poor clinical outcomes in six cancer types. Dr. Harris's findings provide an intriguing means of assessing the potential role of CIN in determining malignancy potential in a broad range of tumors and, as new molecular signatures are revealed through this innovative system, will undoubtedly lead to a more tailored approach to therapy in cancer treatment.
Carter SL, Eklund AC, Kohane IS, Harris LN, and Szallasi Z. 2006. A signature of chromosomal instability inferred from gene expression profiles predicts clinical outcome in multiple human cancers. Nature Genetics 10:1038
Dr. Nazneen Rahman of the Institute of Cancer Research, London, is a recipient of a fiscal year 2004 Breast Cancer Research Program Era of Hope Scholar Award to identify and characterize genetic factors that play an important role in causing breast cancer. Women who carry mutations in the breast cancer genes BRCA1 and BRCA2 have a high probability of developing breast cancer, but these genes only account for a very small proportion of breast cancer families. Weaker (low penetrance) genes, that confer small increases in risk of breast cancer, are suspected in the majority of familial breast cancers and in some nonfamilial breast cancers. However, few of these weaker genes have been identified to date. Thus, the majority of genes that increase breast cancer risk remain to be identified. Dr. Rahman's main objective is to identify these breast cancer susceptibility genes. To accomplish this goal, Dr. Rahman has collected clinical information and samples from over 3000 familial breast cancer families. She has been analyzing genes that are known to interact with the known breast cancer genes, such as BRCA1 and BRCA2, in processes that repair damaged DNA. This work has led to the identification of two new breast cancer genes, ATM and BRIP1. These DNA repair genes have been suspected to have a role in breast cancer susceptibility but molecular proof has been lacking. Dr Rahman used a familial case-control design to show that mutations in these genes occur at increased frequency in familial breast cancer compared to women without cancer. Both genes confer a twofold increase risk of breast cancer which equates to a ~15% risk of breast cancer by age 60.
Renwick A, Thompson D, Seal S, et. al. 2006. ATM mutations that cause ataxia-telangiectasia are breast cancer susceptibility alleles. Nature Genetics 38(8):873-875.
Seal S, Thompson D, Renwick A, et al. 2006. Truncating mutations in the Fanconi anemia J gene, BRIP1, are low penetrance breast cancer susceptibility alleles. Nature Genetics, in press.
Breast tumor cells produce a cytokine called vascular endothelial growth factor (VEGF) that stimulates blood vessels to grow toward the cluster of developing breast cancer primary tumors or breast cancer metastasis. The VEGF binds with KDR receptors expressed on blood vessel cells and stimulates the blood vessels to provide the nutrients for the rapid growth of the breast cancer tumor. Thus, the VEGF plays an important role in the development of breast cancer primary tumors or breast cancer metastasis. Dr. Michael G. Rosenblum of M. D. Anderson Cancer Center received a Fiscal Year 2001 (FY01) Breast Cancer Research Program Idea Award to evaluate the VEGF targeted novel agents that could inhibit breast cancer neovasculature growth. Dr. Rosenblum and his colleagues developed a new fusion protein containing growth factor VEGF121 and the recombinant toxin gelonin (rGel) that targets the VEGF pathway. The investigative team examined the antitumor effect of this agent in both orthotopic and metastaic tumor models of SCID mice. They found that treatment of mice bearing orthotopically placed MDA-MB231 tumors with this therapeutic agent, i.e. VEGF121/rGel, resulted in significantly decreased tumor growth compared to control. In addition, the agent was found to have a relatively long half life in the blood despite significant uptake in the kidney. Furthermore, the team also tested the antitumor activity of this agent in a metastatic MDA-MB231 nude mouse model. It was found that lung metastatic lesions were reduced by 58% in the animals treated with this agent compared to control. Additionally, the vascularity of metastatic foci was significantly reduced. Dr. Rosenblum's findings hold a promise for fusion toxin VEGF121/rGel as a therapeutic agent because no other vascular targeting agents have thus far demonstrated such unique effects in an in vivo model. Dr. Rosenblum further plans to study how toxins work at the molecular level and how to more effectively employ these agents for therapeutic advantages.
Ran S, Mohamedali K, Thorpe P, et al. 2005. The vascular-ablative agent VEGF(121)/rGel inhibits pulmonary metastasis of MDA-MB-231 breast tumors. Neoplasia 7:486-496.
Dr. Erkki Ruoslahti of The Burnham Institute received a Fiscal Year 2001 Breast Cancer Research Program Innovator Award to develop tumor vasculature-targeted therapy for the treatment of breast cancer. Breast tumor grows only if blood vessels continue to nurture the tumor and grow with it. The growing breast tumor blood vessels are distinct from the blood vessels of normal breast tissue (and of other normal tissues). The lymphatic vessels, which are a major route through which breast cancer spreads, are distinct from normal lymphatic vessels. Destroying the blood vessels upon which a tumor depends is an effective way of destroying the tumor. Dr. Ruoslahti's main goal is to advance the potential of therapeutic agents that could target breast cancer vasculature, both the blood vessels and the lymphatic vessels, eliminating potential side effects from targeting angiogenesis in tissue repair. Dr. Ruoslahti has used libraries of phage-displayed peptides to identify specific markers of blood vessels and lymphatics of tumors and premalignant lesions. Dr. Ruoslahti's proposed therapy is different from other anti-angiogenic therapies because he has developed therapeutic agents that directly zero in on tumor tissues by making use of the unique features of the vascular system. The homing peptides identified by Dr. Ruoslahti have shown promise as targeted drugs to stop the growth of breast tumors and prevent metastasis. The therapy has the potential additional benefit of alleviating the toxic side effects associated with many therapeutic cancer agents. Furthermore, Dr. Ruoslahti has identified the vasculature receptors for homing peptides that could represent novel "druggable" targets for the development of anticancer agents.
Akerman ME, Chan WC, Laakkonen P, Bhatia SN, and Ruoslahti E. 2002. Nanocrystal targeting in vivo. Proceedings of the National Academy of Sciences of the United States of America 99:12617-12621.
Ruoslahti E. 2002. Drug targeting to specific vascular sites. Drug Discovery Today 7:1138-1143.
Laakkonen P, Porkka K, Hoffman JA, and Ruoslahti E. 2002. A tumor-homing peptide with a lymphatic vessel-related targeting specificity. Nature Medicine 8:743-751.
Laakkonen P, Akerman ME, Biliran H, Yang M, Ferrer F, Karpanen T, Hoffman RM, and Ruoslahti E. 2004. Antitumor activity of a homing peptide that targets tumor lymphatics and tumor cells. Proceedings of the National Academy of Sciences of the United States of America 101:9381-9386.
Pilch J, Brown DM, Komatsu M, Jarvinen TA, Yang M, Peters D, Hoffman RM, and Ruoslahti E. 2006. Peptides selected for binding to clotted plasma accumulate in tumor stroma and wounds. Proceedings of the National Academy of Sciences of the United States of America 103:2800-2804.
Biomimetic Composite Scaffold for Breast Reconstruction Following Tumor Resection
Posted September 29, 2006
Charles W. Patrick, Jr., Ph.D., University of Texas M.D. Anderson Cancer Center, Houston, Texas
Breast cancer patients are limited when it comes to available breast reconstructive techniques, though the rate of breast cancer reconstruction has risen 174% in the past 10 years. With the support of the fiscal year 2002 (FY02) Concept Award, Dr. Charles Patrick, Jr. and his colleagues are studying a novel rehabilitative strategy that, if successful, would allow patients to restore breast mound tissue following a mastectomy or lumpectomy using their own adipose tissue cells. The group hypothesized that by combining two natural polymers, collagen and chitosan, they could form a scaffold that mimics the human extracellular matrix (ECM) structure and provides a suitable environment for preadipocyte adhesion and expansion. The goal is to provide a sufficient volume of viable fat tissue from a patient's own cells such that the deficiency in breast volume taken during the cancer surgery can be replaced.
Dr. Patrick and colleagues established various conditions to blend chitosan and collagen, and after scanning electron microscopy and optical microscopy analyses, selected one set of conditions for further testing. Preadipocytes (PA) seeded on the scaffold in vitro demonstrated viability throughout the entire scaffold. Given these encouraging results, the scaffolds were then analyzed in a rat in vivo model system where they proved to be biocompatible, causing no apparent inflammation. Compared to acellular controls, PA-seeded scaffolds implanted in rats were shown to be well vascularized (yielding a vascular density of 1%-1.2%), remained intact upon gross inspection, and displayed a higher lipid density, an indication of adipogenesis. PA-seeded scaffolds also showed a significant increase after only 14 days of the in vivo study, becoming almost totally infiltrated with adipose cells and new matrix material.
These promising results demonstrate that the field of breast reconstructive surgery is on the brink of accomplishing in vivo tissue regeneration. The advancement of post-operative rehabilitation in this field can provide a positive influence on the patient's quality of life for all breast cancer survivors.
Patrick CW. 2004. Breast tissue engineering. Annual Review Biomedical Engineer 6:109-130. Review.
Patrick CW. 2000. Adipose tissue engineering: the future of breast and soft tissue reconstruction following tumor resection. Seminars in Surgical Oncology 19:302-311.
Wu X, Black L, Santacana-Laffitte G, Patrick CW. 2006. Preparation and assessment of glutaraldehyde cross-linked collagen-chitosan hydrogels for adipose tissue engineering. Journal of Biomedical Materials Research, in press.
Frye CA, Cromeens BP, Kim KS, Wu X, Beahm E, Patrick CW. Adipogenesis within a vascularized collagen-chitosan construct for soft tissue engineering applications, Adipocytes, submitted.
Despite technical advancements in breast cancer surgical procedures, adequate breast tumor resection remains a serious issue given that over 30% of these tumors will recur locally.
Medical Hyperspectral Imaging (MHSI) technology is a novel, camera-based method of imaging spectroscopy that integrates spatial and spectroscopic data from tissue into a simple image. Dr. Jenny Freeman and her colleagues have developed an innovative use of this technology with the support of a fiscal year 2002 Concept Award. The goal of their research was to provide surgeons with a more accurate indication of a margin of excision that is free from tumor at the time of surgery. Dr. Freeman and colleagues modified existing MHSI technology and assessed its value by using it during a surgical procedure in the expectation it could distinguish between normal and cancerous breast tissue in rats exposed to 1,2-dimethylbenz(a)anthracene.
Dr. Freeman's results showed MHSI can deliver a 40-micron resolution that is easily interpreted and has the ability to differentiate between tumor and normal tissue during a real-time operating procedure. Interim analysis on 16 full sets of tumor bed data showed that MHSI correctly identified tumors in all cases and detected 0.5-mm tumors in the resection bed whereas standard histopathology failed to do so in two cases. With results of 89% sensitivity and 90% to 94% specificity, MHSI could deliver tumor-grade information in the operating room. This study also moves the application of MHSI technology forward into preliminary tissue diagnosis and advances the concept toward true "optical biopsy."
Due to its rapid, noninvasive, and cost-effective evaluation of residual cancer in the tumor bed, this preliminary study indicates MHSI technology could provide surgeons with near-real-time information regarding the adequacy of margins of resection at the time of breast cancer surgery.
Freeman JE, Panasyuk S, Rogers AE, Yang S, Lew R. 2005. Advantages of intraoperative medical hyperspectral imaging (MHSI) for the evaluation of the breast cancer resection bed for residual tumor. Journal of Clinical Oncology, ASCO Annual Meeting Proceedings, Vol. 23, No. 16S (June 1 Supplement) 2005:709.
Freeman JE, Yang S, Panasyuk SV, Lew RA, Ngo D, Faller DV, Rogers AE. In situ evaluation of residual breast tumor and tumor grade using medical hyperspectral imaging (MHSI). Journal of Clinical Oncology, ASCO Annual Meeting Proceedings, 2006, Abstract ID 10677.