Lung cancer is the leading cause of cancer death worldwide, with five-year survival rates among the lowest for commonly diagnosed cancers. The high mortality rate is partially due to the lack of effective treatment options since surgery and chemotherapy are common options, yet non-curative. The epidermal growth factor receptor (EGFR) gene is overexpressed in a majority of lung cancers. Researchers recently discovered a new drug designed to target the product of this gene. Although the drug didn’t benefit the majority of patients, a positive response was often seen in non-smoking women of Asian descent. At the BC Cancer Research Centre, Trevor Pugh is researching why this drug works for this subgroup and not for other patients. Using tumour samples and patient outcomes data, he is searching across the entire genome to pinpoint specific genetic features shared by drug-responsive tumours in patients with lung cancer. Ultimately, his work could result in improved diagnostic tests for predicting who will benefit from specific therapies, and new candidates for gene-targeted cancer drugs.
Research Location: BC Cancer Research Centre
Regulatory mechanisms of the anti-apoptotic NAIP gene during cellular stress and malignancy
Apoptosis, or programmed cell death, is a critical physiological process that is turned on and off as appropriate to eliminate abnormal cells. When this switching process goes awry, it can lead to a variety of diseases including cancer. The genetic mechanisms that inhibit activation of the apoptosis protein (IAP) family include molecules that sequester key enzymes necessary for turning on and sustaining the process of programmed cell death. Neuronal apoptosis inhibitory protein (NAIP) is particularly interesting because expression of NAIP is reported to be highly elevated in various leukemias. In addition, NAIP is commonly deleted in the most severe cases of spinal muscular atrophy (SMA) and studies also have shown that a specific copy of this gene is required to suppress replication of the bacterial pathogen that causes Legionnaire’s disease. Researchers have also proposed that expression of NAIP in neurons of patients with Alzheimer’s disease can limit the high levels of cell death. Mark Romanish is studying the expression and regulation of NAIP to better understand its role and function in health and disease. Apoptosis is a highly regulated process receiving many activating and inhibiting signals, but the final outcome relies on which signals tip the scale. Therefore, the question of gene regulation becomes particularly important since those genes capable of rapid activation are more likely to influence the ultimate fate of a cell.
Mechanism of androgen regulated expression of SESN1, a potential tumor suppressor
Male sex hormones (androgens) regulate tumour growth in prostate cancer. The only effective treatment for advanced prostate cancer is the removal of androgens using medication, or the surgical removal of the testes — treatments that cause impotence and a decreased sex drive. The results are usually temporary since some tumour cells survive, become independent of androgens, and continue to grow. Prostate cancer cells depend primarily on the androgen receptor, which encodes genetic information, for growth and survival. Gang Wang is studying how the androgen receptor decreases the expression of the SESN1 gene — a gene that may inhibit the growth of prostate tumour cells. Wang believes the SESN1 gene is no longer repressed when patients receive hormone therapy. This would explain the initial suppression of prostate cancer cells seen in these patients and the subsequent reappearance of cancer cells which later follows. Wang will confirm if the androgen receptor begins lowering the gene following therapy, allowing the cancer cells to grow. If so, the SESN1 gene could be a promising therapeutic target for treating prostate cancer.
Molecular Imaging of Cancer with Positron Emission Tomography
Recent developments in imaging devices provide researchers with powerful tools to detect cancers and explore the impact of therapy on tumour cells. This research program plans to leverage the strengths of positron emission tomography combined to computed tomography (PET/CT) to characterize and rapidly assess response to therapy in 3 common cancers (breast, prostate, and lymphoma) and combine this information with other predictors of aggressiveness and treatment failure. PET/CT imaging is a powerful technique that combines the strenghts of a PET scanner (which can measure tumor receptors and metabolic activity) with those of a CT scanner (which provides detailed images of a patient’s anatomy). The combination of both approaches could rapidly identify patients that are likely to fail conventional therapy and offer them alternatives that are better suited to the nature of their cancer. The research program is designed around 3 core themes. The first research them focuses on the development of methods to predict the outcome of patients with breast cancer who are treated with chemotherapy or hormone therapy. We will pursue ongoing work to develop animal models of breast cancer and imaging methods to monitor response of these tumors to chemotherapy and hormone therapy. We will also conduct clincial studies to correlate the results of imaging studies performed with PET/CT with outcome and response to therapy. The second theme focuses on the development of new probes that target specific proteins that are overexpressed at the surface of breast and prostate tumors. These probes might eventually be translated into clinical studies as breast and prostate cancer diagnostic agents for use with PET/CT, or even for therapy by tagging them with radioisotopes that can destroy tumor cells by proximity. The last theme proposes practical research studies of immediate clinical interest. We will assess the accuracy of PET/CT imaging in staging prostate cancer (with 2 radiopharmaceuticals designed to assess tumor lipid synthesis and bone turnover). We will also extend to the Vancouver site an ongoing study that assesses PET/CT imaging to predict the early response to chemotherapy in large cell lymphoma.
Population-Based Genetic Studies of Cancer and Healthy Aging
The number of elderly Canadians is increasing as the baby boomers age. Insight into how to promote healthy aging, coupled with advice that can be provided to our population as it ages, will influence Canada’s healthcare costs, as well as the quality of life of a large segment of our population. Cancer and aging are intimately connected. Cancer incidence rises with age, and this increase accelerates dramatically over 60 years of age. Cancer and other aging-associated diseases like cardiovascular disease are thought to result from the interaction of numerous genetic and environmental or lifestyle factors. Population-based studies that use large groups of affected and unaffected individuals are now the preferred method to study the genetics of complex diseases. This program has clinical relevance and involves close collaboration with clinical experts to study healthy aging and two specific cancers, non-Hodgkin lymphoma and cervical cancer. The overall objective is to discover genetic factors that contribute to susceptibility to cancer or confer long-term good health. The program will use state-of-the-art genetic analysis methods, and over the next 5 years will expand these projects and add additional types of cancer. This coordinated study of cancer and healthy aging is a unique and innovative approach by which we will increase our understanding of the connection between cancer and aging and benefit from new knowledge regarding the basis of common aging-associated diseases like cancer. This research will lead to development of clinically useful markers that will help individuals avoid developing diseases as they age.
Genetic approaches to characterize mammary stem and progenitor cells
A stem cell can both self-renew and divide to form differentiated daughter cells. In adult tissues, stem cells have the ability to generate mature cells of a particular tissue through differentiation, and to do so multiple times. Such cells were recently identified in a mammary gland, and demonstrated their capacity to regenerate their structures in other breast tissues. This was an important discovery, as it is speculated that these stem cells are central to the development of breast cancer. Because stem cells are relatively long-lived compared to other cells, they have a greater opportunity to accumulate mutations leading to cancer. Also, these cells have a pre-existing capacity for self-renewal and unlimited replication. The idea that stem cells are inherent to malignant transformation has wide-stretching implications for therapeutics, particularly with regards to drug resistance. Angela Beckett is studying the growth and differentiation of normal breast stem cells, which will provide knowledge about what drives malignant transformation and how to prevent cancer initiation. By obtaining basic information on stem cell regulation, this research is taking an important step in designing novel therapeutic approaches to their malignant counterparts, cancer stem cells.
The endothelium: Function and dysfunction
The interior lining of blood vessels is known as the endothelium. Endothelial cells, which make up this inside layer of all blood vessels, are remarkably responsive to changes that occur in the blood and tissues, both under normal conditions and in disease states, sending signals back to the blood and tissues to organize a response. Endothelial cells initiate and direct the growth of new blood vessels within a tissue that is not receiving a sufficient supply of oxygen and nutrients. This growth of new blood vessels can be either beneficial or detrimental to a person’s health. When blocked blood vessels are contributing to the lack of sufficient blood supply (e.g. hardening of the arteries or diabetes), the body’s creation of new blood vessels can prevent tissue damage and promote healing. However, new blood vessels also required for cancer growth by providing the tumour with the oxygen and nutrients it needs. Dr. Aly Karsan is studying several molecules on the surface of endothelial cells to determine how they regulate the growth of new blood vessels. With greater knowledge about the molecular processes underpinning blood vessel growth, he hopes to identify new ways to either promote or restrict these processes to combat a variety of diseases.
Priority setting methods for cancer control and care
Priority setting is the focus of health economics—a branch of economics concerned with issues related to the scarcity of health care resources. With cancer expected to be Canada’s primary cause of death by 2010, priority setting in cancer control and care is imperative. An aging population, rising health care costs and increasing demand have resulted in the need for identifying effective and cost-effective ways to improve cancer patient outcomes. Basing his work on an internationally-recognized economic framework for priority setting (called Program Budgeting and Marginal Analysis), Dr. Stuart Peacock is developing new evidence-based methods to help health care decision-makers determine the most effective cancer interventions to fund. His research will develop three significant innovations within this framework: methods to address improvements in life expectancy and quality of life from health programs; methods to address community preferences and equity concerns; and measures to evaluate priority setting and evidence-based decision-making. Dr. Peacock’s goal is to develop an evidence-based framework for decision-making in cancer services that is transparent, explicit and accountable.