Role of CXCR4-LASP-1 axis in modulatingtheactivity of Argonaute2-TNRC6 in breast cancer cell
Breast cancer is the most commonly diagnosed cancer in women, accounting for 32% of all cancers in women. One of every eight women (13%) will develop breast cancer in her lifetime and breast cancer is one of the leading causes of cancer deaths in women. Most of the deaths in breast cancer patients are due to metastatic spread to distant organs like lungs, bone and brain and not the primary cancer in the breast. When the cells become abnormal to a variety of reasons and multiply uncontrollably, it forms a mass or what we call a lump in the breast. This primary breast cancer spreads to other organs as the individual cells in the lump undergo additional changes at the molecular level that makes them move, move and move. The molecular system that makes the tumor cells move is called ‘CXR4-LASP1 axis’. LASP-1 protein molecule, a part of the axis, is virtually absent in the normal breast tissue expect in the myoepithelial cells that contract like muscle for milk letdown off the tiny glands in the breast. When the benign tumor called DCIS forms, LASP-1 begins to appear in the breast epithelial cells. When the breast cancer cells become invasive they make tons of LASP-1. This enables the breast cancer cells to migrate and multiply more. Now the question is how come the breast cancer cells suddenly become so mobile and spread to the lungs, bones and the brain. We have some preliminary data that indeed demonstrate that the chemokine receptors (CXCR4 in particular) may help LASP-1 to the messenger RNA repression and trashing machinery that will ultimately alter protein makeup of the tumor cells that presumably will make the cancer cells multiply faster and start migrating to far off places like lungs. We hypothesized that CXCL12-CXCR4-LASP1 axis will modify the protein makeup of the cancer cell that directly or indirectly that enables the breast cancer cell mass to mature into a big lump and eventually migrate to distant organs like lung and bones. The experiments proposed herein addresses these concerns and will further our basic understanding of the spread of breast cancer to other organs. LASP-1 will become a therapeutic target and form the basis for novel pharmaceuticals that will help contain the growth and the spread of the breast cancer to lungs, bones and brain. Successful accomplishment of the goals of this project will enhance our basic understanding of the mechanisms breast cancer progression and metastasis which will eventually lead to translational discovery of novel small molecule drugs for chemotherapy or for use along with with radio- or immunotherapy.
Role of nitric oxide in regulating the extracellular matrix in breast
Cells are embedded in the extracellular matrix (ECM), a collection of soluble and insoluble substances secreted by different types of resident cells in tissues. Although having been thought to be merely the inert scaffolds of tissues, the ECM is now known to dynamically interact with cells and critically influence cell/tissue behavior. In particular, during the course of tumor progression, cells and ECM co-evolve to take part in a cellular environment termed “tumor microenvironment (TM)”, which functions to promote the growth and progression of tumor cells. In particular, the ECM in tumorous tissues is denser and stiffer than that in normal tissues, conferring stronger mechanical strain that disrupts tissue architecture and makes cells more migratory—the basic mechanism of invasive cancer cells. In fact, stiffer ECM is a major contributor to the initiation of solid tumors. Our long-term goal is to investigate how cell-ECM interaction controls tissue homeostasis, whereas its defect contributes to stiffer ECM and tumor initiation. Specially, the short-term goal of this project is to determine whether ECM stiffening in the breast is attributed to a local deficiency of nitric oxide (NO), a gaseous signaling molecule produced throughout the body, and whether this leads to breast tumor initiation. The proposed project is relevant to cancer because defining a local reduction of nitric oxide (NO) level in the breast as the key to stiffening of the ECM will not only advance our understanding of the cause of breast tumor, but also justify the development of a method modulating NO level and ECM stiffness for prevention and treatment of the disease.
Proinflammatory cytokines IL-23 and IL-17 in radiotherapy induced oral mucositis
Cancer treatments can have negative impacts on normal functions in the body. For example, patients receiving radiation of the head and neck or chemotherapy can develop severe damage to the lining of the oral cavity, which is called oral mucositis. Destruction of the oral epithelium is painful and can make it difficult to eat, drink or speak. Also, oral mucositis can lead to an increased risk of serious infection caused by fungus normally found in the mouth. If a patient develops oral mucositis their ncer treatment is much more expensive and the damage can be so severe, that patients stop their treatment. There are no good treatments for oral mucositis. We hope to understand the proteins and cells involved in the development of oral mucositis. A better understanding of oral mucositis will allow the development of better drugs to treat oral mucositis and fungal infections, so patients remain comfortable and can stay on their cancer treatments.
lmmunosuppressive mechanisms and response prediction in HER2+ early breast cancer
Approximately 20% of breast cancer patients are diagnosed with amplifications in the HER2 gene. While a number of novel therapeutic strategies are being developed to treat this major subset of breast cancers, no reliable biomarkers have yet been identified that predict which patients will achieve optimal response to specific anti-HER2 treatment regimens. Even in the increasingly accepted dual-HER2 blockade paradigm, which involves treating patients with both Herceptin and pertuzumab (Perjeta), up to 55% of patients do not achieve complete response. Completion of this innovative and impactful study will result in the development of novel biomarkers capable of predicting which patients will most benefit from dual-HER2 preoperative therapy, as well as reveal new therapeutic avenues for patients with aggressive HER2+ breast cancers.
Stereoselective Synthesis of 2-Deoxy-glycosides and Thioglycosides in Antitumor Natural Products
2-Deoxy glycosides are a class of biologically important carbohydrates which often exist as critical subunits in naturally occurring potent antitumor antibiotics. Due to the fact that only limited amounts of these antibiotics can be isolated from natural sources, it is critical to develop efficient methods and strategies for the chemical synthesis for the 2-deoxy sugar subunits in order to access sufficient quantities of these natural antibiotics and their analogues for biological studies. The goal of this proposal is to develop new synthetic methodologies for stereoselective preparation of 2-deoxy glycosides and their more stable thioglycoside analogs in a highly efficient manner. These methods, once developed, will be applied to the synthesis of 2-deoxy-sugar subunits of potent natural antitumor antibiotics in order to facilitate further total synthesis for their structure and activity relationship (SAR) studies. It is the hope that our synthetic efforts will ultimately lead to development of effective therapeutic agents for the treatment of cancer diseases.
The Role of p31Comet in Breast Cancer Progression and Therapy
The spindle assembly checkpoint (SAC) ensures the stability of the genome (DNA) by preventing cell division until the duplicated genome is accurately segregated between the newly forming daughter cells. Errors in this process greatly contribute to the generation of cancer. SAC activity is also required for the function of a family of drugs, the taxanes, used in the treatment of breast cancer. Although the characteristic genomic instability in breast tumors and the frequency of resistance to taxanes implicate impaired SAC function in tumors, the evidence for widespread deficiencies in the SAC is lacking. However, cells possess machinery for inactivating the SAC and allowing cells to divide and proliferate. The role of this machinery in tumors is not well known. Our preliminary data indicate that the activity of p31Comet, a component of this machinery, is increased in breast tumors. The goal of this proposal is to determine the role that increased p31Comet has in the creation of tumors, whether this role can be exploited to treat cancer, and what impact increased p31Comet activity has on the successful use of taxanes in treating breast cancer. Successful testing of our hypotheses will improve our understanding of breast cancer biology and will provide the foundation for the development of an assay to predict a patient’s response to taxanes and may lead to the generation of novel therapeutic agents.
TA Novel Plant Viral Nanoparticle Drug Delivery System for Treatment of Aggressive HER2+ Breast Cancer
Approximately 200,000 women will be diagnosed with breast cancer this year and more than 40,000 of those will die from the disease. 25-30% of breast cancers are classified as HER2 positive (HER2+). HER2+ means that the cancer cells in these patients upregulate the protein human epidermal growth factor receptor 2 (HER2). HER2+ cancers are aggressive, and a woman with this diagnosis has a poor prognosis, high rate of metastasis, high risk of relapse, resistance to hormone replacement therapies, and high risk of rapid progression to death. The treatment of HER2+ cancers typically involves chemotherapy combined with an antibody known as trastuzumab (the commercial name of this therapeutic is Herceptin). Herceptin treatment is successful because this antibody specifically recognizes and binds to HER2, thus blocking its ability to signal cell growth and invasion. Nevertheless, cardiotoxicity and development of resistance are critical hurdles to overcome. Consequently, improving therapies for the treatment of HER2+ breast cancer patients is not only a critical goal for medicine, but also the key to increasing survival. We propose the next-generation of HER2-targeted therapies based on nanoparticles from plants. These nanoparticles can be engineered with hundreds of HER2 targeting ligands and chemotherapy. This is expected to increase efficacy of the treatment while reducing side effects.
Targeting CXCR7 Mediated Vascular Interactions in Glioblastoma
Despite major clinical and basic science efforts, malignant brain tumors remain highly lethal. These tumors are treated aggressively and a fraction of the tumor still remains resistant to current therapies. Recent work has suggested that these resistant cells are capable to regrowing the entire tumor and as such, are referred to as cancer stem cells (CSCs). Key to the function and malignancy of CSCs is how they interact with their surrounding microenvironment. We are interested in signals produced by the microenvironment that contribute to CSC growth as well as therapeutic resistance and have identified a class of signaling molecules that are likely to be involved in CSC-microenvironment communication, the chemokines. We hypothesize that chemokines directly regulate the interaction between the CSCs and their microenvironment in malignant brain tumors, and targeting chemokines will prevent this interaction and result in decreased CSC and overall tumor growth. The short term goal of the project is to evaluate how chemokines and CSCs interact directly during tumor formation using live imaging models of chemokines and CSCs enriched directly from human patients. An additional short term goal is to test the effect drugs that target chemokine receptors and evaluate CSC growth under these conditions. The long term goal of this project is to develop a strategy to uncouple the communication between CSCs and their microenvironment that can easily be translated into clinical practice for malignant brain tumors and other cancers in which CSCs represent a therapeutic target. The drugs we proposed to test in our brain tumor model are under development so our results will provide rationale for early phase trials. Our project directly relates to cancer in that we are testing an important cancer biology concept, how CSCs communicate with their surrounding microenvironment using both tumor models and primary human tumor tissue. Our efforts are aimed at identifying communication pathways used by CSCs and developing therapies to disrupt the communication, thereby providing a new therapeutic strategy for a variety of tumors in which CSCs are driving malignancy including brain, breast, colon, leukemia, and lung cancer.
Inhibition of Etv2 function as a novel strategy to prevent tumor-induced angiogenesis
Blood vessel growth is commonly associated with cancer. Inhibition of blood vessel growth is one of the most promising strategies to prevent tumor growth. However, current strategies often fail to prevent tumor growth due to the development of resistance to the therapies. Zebrafish has emerged as a novel powerful model system to study blood vessel development and tumor growth which can be easily observed in transparent embryos and adults. We have previously identified a novel protein, Etv2 as a key regulator of blood vessel development in zebrafish embryos. We have also established a system to study growth of human tumors in zebrafish embryos. In this proposal we suggest that inhibition of Etv2 function may prevent tumor-induced blood vessel growth and reduce tumor growth. The proposed experiments will utilize zebrafish model to test if Etv2 is important for blood vessel growth during later developmental stages and in adults, when tumors typically arise. Furthermore, it will be tested if blocking Etv2 function will prevent tumor growth. In addition, it will be analyzed if similar to zebrafish, Etv2 in humans is associated with tumor growth. This study will determine if inhibition of Etv2 function may present a novel and potentially advantageous strategy to inhibit tumor growth. In the long term, these results may lead to the design of new drugs and treatments to prevent tumor formation in humans.
The vast majority of cancer deaths are due to metastatic disease. While various treatment options are available, chemotherapy prevails as the principle treatment especially in the case of highly aggressive and metastatic cancers. However, even though potent chemotherapeutic drugs are available to oncologists, the dose of these agents is constrained by their toxicity to normal tissue, because they are distributed within cancer and healthy tissues in a non-specific manner. Furthermore, metastases present unique challenges due to their smaller size, higher dispersion to organs, and lower vascularization than primary tumors, making them less accessible to therapeutic agents. To effectively seek and destroy metastases, we exploit nanotechnology to fabricate a 100-nm-long multi-component nanoparticle, called the nanochain. Due to the unique material properties that appear at the nano-scale, nanoparticles provide many potential benefits and new opportunities to address the complexity of metastatic cancer. The nanochain particle is made of different nanospheres connected one to another much like a stack of Legos. Specifically, we link three magnetic nanospheres made of iron oxide and one a lipid nanosphere filled with the drug. We then decorated the surface of the nanochain with multiple sites that bind with integrins. Integrins act as glue between the metastatic cancer cell and the lining of a blood vessel in the colonized organ. To home in on the cancer marker (integrin), we need a nanoparticle that would drift out of the central flow of the blood stream and to the blood vessel walls. The most common shape of nanoparticles is a sphere, but a sphere tends to go with the flow. However, due to its size and shape, the oblong nanochain tumbles out of the main current and skirts along vessel walls. Then, once the nanochain laches on one integrin binding site, others grab hold resulting in superior attachment of the nanochains onto metastases compared to spherical nanoparticles. A few hours later, after nanochains slip from the blood stream and congregate in metastases, a wire coil is placed, called a solenoid, outside near the body. Electricity passed through the solenoid creates a “mild” radiofrequency field (similar to frequencies of FM radio). The field causes the magnetic tails to vibrate, breaking open the liposome spheres. The application of radiofrequency facilitates rapid release of high amounts of free drug into metastatic tumors capable of spreading to deep regions of metastases, which are otherwise inaccessible by current drug delivery strategies. In animal studies, we found that this can result in at least 10 times greater cell death in metastatic tumors compared to traditional treatments.
Molecular Mechanisms of Invadopia Formation in Breast Cancer Cells
The migration of cancer cells away from the primary tumor and their subsequent spread to distant organs is regarded as a fatal step in cancer progression and is associated with the majority of cancer mortalities. This process, called metastasis, is the leading cause of mortality from breast cancer patients. Therefore, understanding the process of tumor metastasis and preparing strategies that may be able to alter this property of cancer cells is a significant priority. In this context, we have found a protein called RhoG that can inhibit the formation of cellular structures called invadopodia that cancer cells use to digest tissue barriers to allow invasion of surrounding tissue. In this proposal, we will characterize this important biochemical pathway to understand the fundamental mechanisms of how invadopodia form and how they contribute to breast cancer invasiveness and metastasis.
Regulation of Autophagy by the Small GTPase Rab20
Lung cancer is poorly understood and current therapies are insufficient to save the lives of patients. Cancer cells require abnormal levels of energy to maintain their high growth rates. Tumors exploit autophagy, a normal cellular process, to meet their increased metabolic needs and survive periods of nutrient limitation and cellular stress. Activation of the pathway undermines the efficacy of many of our present chemotherapeutic strategies. Recent work with mouse models representing roughly 30% of Non Small Cell Lung Cancers (NSCLC) revealed that inhibition of the autophagy pathway extends survival of the mouse, suggesting that autophagy-inhibiting therapies may have clinical benefit for this and potentially other tumor types. The small GTPase Rab20 emerged as a potent regulator of autophagy in a recently conducted largescale screen for novel autophagy regulators. This proposal determines the mechanism by which Rab20 positively regulates autophagy and examines whether it may be a new therapeutic target in lung cancer.
Targeting IL-11 in breast tumor initiating cell-mediated metastasis
The lifetime risk of developing invasive breast cancer is 1 in 8 in women in the United States and 20% of the breast cancer patients die. Cancer cell spread from the breast tissue to distant organs accounts for 90% of breast cancer caused deaths. We aim to discover how cancer cells interact with each other and talk to other blood cells, such as platelets, during the traveling (circulation) and spreading (metastasis) from one place to another. We have identified a subset of breast cancer cells with stem cell properties, called breast cancer stem cells or tumor-initiating cells which tend to mediate metastasis. These cells promote metastasis by forming multi-cell clusters with platelets during circulation. A secreted molecule, interleukin-11 (IL-11), enhances the process. This project is to identify the molecular mechanisms by which IL-11 regulate breast cancer stem cell and platelets clusters. We will explore strategies to block IL-11 functions with a goal of reducing metastasis and decreasing breast cancer deaths in the clinic.
Impact of the tumor microenvironment on matrix metalloproteinase activity
Metastasis, the spread of cancer from the original tumor to other sites in the body, is the main cause of death in most cancer patients. During the first step in metastasis, invasion, cancer cells break away from the original tumor and migrate through the tissue. In order to escape the primary tumor, cancer cells need to break down barriers in the dense surrounding tissue using enzymes called matrix metalloproteinases (MMPs). High levels of MMPs are observed in almost all types of cancers, including breast, colon, and pancreatic cancer, and increased levels of MMPs are associated with poorer outcomes. The goal of this proposal is to understand the factors that lead to increased levels of MMPs during disease progression. During disease progression, one of the first signs of a tumor is a hard lump. This tissue stiffening was once thought of as just a byproduct of the cancer cells growing uncontrollably. However, more recently, it has become clear that this tissue stiffening is not just an after effect but can also control the behavior of the cancer cells. Here, we will investigate how tissue stiffening controls MMP activity during the first stages of cancer progression. First, we will use a cell culture model system in which we can carefully control tissue stiffness to investigate how the changes in tissue stiffness observed during cancer progression affect MMP activity and cell migration. Then we will extend these studies to human tissue samples in which we will spatially map MMP activity and tissue stiffness to understand how MMP activity changes with disease progression. Through this investigation, we will develop a clearer picture of the factors that lead to increased levels of MMPs during cancer progression. Understanding these factors will contribute to the identification of new therapeutic targets to reduce cancer cell invasion and metastasis.