Unraveling the genetic code: Sandra Patkovic prepares to start a sequencer. The gene sequences on the monitor in the background provide crucial

Transcription

1 22 Unraveling the genetic code: Sandra Patkovic prepares to start a sequencer. The gene sequences on the monitor in the background provide crucial information about the tumor s growth history and possible therapeutic approaches.

2 Medicine 23 Bayer research _23 Gene analysis and biomarkers support precision diagnostics and new therapies against cancer Photos: Peter Ginter (15), Matthias Lindner (1)/Bayer AG Health is a molecular thing: individual codes inside our body s cells are increasingly helping doctors to precisely analyze patients. makes use of knowledge about the microcosm inside us: genome-based studies and biomarkers are expanding the range of diagnostic tools available to doctors, enabling them to give cancer patients the most targeted treatment possible. Fruitless attempts at treatment and unpleasant side effects could be further limited in the future as a result. In addition, today s molecular medicine is giving rise to new active substances with an even more targeted and direct therapeutic effect. Using the methods of personalized medicine, Bayer researchers are working on improved cancer treatments. Multimedia version with audio image gallery and animated graphics on the web: bayer.de/r009

3 24 Wafer-thin tissue: prior to analysis under a microscope, samples of biological materials in this case brain tissue from mice must first be prepared. Embedded in paraffin, they are cut into thin slices and examined.

4 Medicine 25 Bayer research _23 Masses of individuals: every tumor is unique. Biology lab technician Kirsten Steiner-Hahn first inspects tissue samples with the naked eye. The tumor samples then undergo additional analytical tests.

5 26 Chilly repository: white vapor clouds the vision of doctoral researcher Tobias Gorges as he opens a tank filled with liquid nitrogen. A supply of tumor samples is stored inside at minus 196 degrees Celsius to serve the needs of medical research.

6 Medicine 27 Bayer research _23 Cell architecture in focus: different dyes help to identify characteristic tissue structures under the microscope, as this section of cancerous lung tissue shows.

7 Medicine All people are unique, and so are all diseases. What we need is customized therapeutic care. Decoding the human genome was an important step along the way to this kind of personalized medicine. Ultrasound, x-ray, computed axial tomography and magnetic resonance imaging are still the chief methods for looking inside the human body and finding evidence of specific disorders. But even more seems possible in the future: new diagnostic methods could deliver a more detailed molecular analysis of a disease, giving doctors key indicators for optimum treatment. This is a critical aspect, because a cancer patient s body, for example, often shows no outward signs of illness for a long time. But somewhere inside, one cell has disrupted the ordered structure of tissues and organs. Where exactly this happens, and what genetic changes are ultimately responsible for the unchecked growth, usually remain unclear. Every tumor has its own individual history. Several genes must change before a healthy somatic cell degenerates, divides uncontrollably, and finally turns into a malignant tumor, explains Dr. Dominik Mumberg, Head of the Cell Cycle & Survival Signaling Department of Oncology Research at Bayer HealthCare. His longterm goal is to be able to compile a detailed genetic profile of a tumor through DNA analysis before a cancer patient begins treatment. In other words, cell biologists identify the altered gene sequences no matter if they have replicated, been eliminated or modified and give oncologists valuable starting points for highly targeted treatment. Analyzing the DNA, and the protein molecules it codes for, provides decisive information about the unique pattern of a disease. This molecular fingerprint of each patient, and his 28 : tailored treatments Medicine of the present: one treatment fits all Cancer patients with e.g. colon cancer Medicine of the future: more personalized diagnostics Cancer patients with e.g. colon cancer Blood, DNA, urine and tissue analysis Biomarker diagnostics Therapy Therapy Effect No effect Adverse effects Effect Different people respond differently to the same therapy: while one treatment brings about the desired success in one group of patients with e.g. colon cancer, it does not change the condition of other groups at all, or even leads to adverse effects (left). The reason: the genetic makeup and metabolic profile of each individual patient influences the effect of a drug. takes these individual patterns of cellular and metabolic products into account in the diagnostic phase: biomarker diagnostics separates patients into groups with similar characteristics, and provides information on the best individual treatment. This should enable all patients to benefit from their own, personal therapy.

8 29 Bayer research _23 Infinite variety: the thin slices of tumor tissue samples already differ significantly, and not only on the outside (photo above). Major differences also exist under the microscope and in their molecular details. Dr. David Henderson and Dr. Joachim Reischl (photo left, from left to right) are therefore searching for biomarkers that characterize the different cancer cells and trying to identify patterns in these features. Tomorrow s tumor therapies will target the characteristics of a specific tumor. or her disease, is our key to personalized medicine, Mumberg explains. In the future, a drug will no longer be prescribed to every patient with the same diagnosis, rather only to specific patient groups, depending on their individual molecular profile, says Dr. Joachim Reischl, Head of the Clinical Biomarkers and Molecular Diagnostics Department at Bayer HealthCare. Through personalized medicine, we want to provide each individual patient with the right medication, at the right time, and in the optimum dosage, Reischl says. This approach opens up entirely new opportunities, because not all cancers are the same, and their manifestations even differ worldwide, as studies have shown. U.S. Americans, for instance, contract intestinal cancer more frequently than Japanese who, in turn, are more likely to suffer from stomach cancer. However, if we observe Japanese immigrants in the USA over one to two generations, this phenomenon reverses, Mumberg says. The causes probably lie in changing environmental conditions, such as diet, often in conjunction with specific viruses. Some cancer patients are already benefiting from the new, personal approach. A DNA analysis of tumor cells reveals details we cannot see with the naked eye, under a microscope or with other imaging methods. That makes more effective therapy possible, Reischl explains. And the range of diagnostic options is growing. One important basis for personalized medicine is biomarkers: biological indicators that provide information on a person and his or her body.

9 Most common cancers North America 1.60 million new cancer cases (total population 345 million) Europe 3.21 million new cancer cases (total population 732 million) Asia 6.09 million new cancer cases (total population billion) Lung cancer Prostate cancer Breast cancer Colon cancer Non-Hodgkin lymphoma Colon cancer Breast cancer Lung cancer Prostate cancer Stomach cancer Lung cancer Stomach cancer Liver cancer Breast cancer Colon cancer 14.8% 13.3% 12.8% 11.0% 4.6% 13.5% 13.2% 12.1% 11.6% 4.5% 14.3% 11.9% 9.6% 8.7% 8.4% 30 Latin America and the Caribbean 0.91 million new cancer cases (total population 576 million) Africa 0.68 million new cancer cases (total population 987 million) Oceania 0.14 million new cancer cases (total population 34 million) Prostate cancer Breast cancer Lung cancer Cervical cancer Stomach cancer Breast cancer 13.6% Cervical cancer 11.8% Liver cancer 7.6% Prostate cancer 5.8% Non-Hodgkin lymphoma 5.5% Prostate cancer Colon cancer Breast cancer Skin cancer Lung cancer 13.3% 12.7% 7.8% 7.5% 7.2% 15.8% 13.1% 12.6% 10.2% 8.9% Source: GLOBOCAN 2008, International Agency of Research on Cancer, Cancer Incidence Worldwide, Most importantly, they give us this information even before a person feels sick, Reischl emphasizes. Familiar examples include blood pressure, as well as liver and blood sugar readings. But modern molecular biology continues to find new markers: genes, protein molecules and metabolic products in urine, blood or tissue make it possible to draw up a unique patient profile. Biomarkers characterize a cancer patient s individual molecular profile Dr. Joachim Reischl and his co-workers in research at Bayer HealthCare therefore work in globally networked teams to search for new biomarkers, which characterize the respective key molecules of a patient and his disease. Depending on the region, they encounter different challenges, because the most common cancers vary from one continent to the next and no two tumor patients respond the same. Even if tumors are discovered in the same organ in two people, and look similar under the microscope, we often find significant differences on the molecular level, says Reischl. Consequently, the first priority in medicine must be to further improve diagnostic methods in the future. To do that, it is crucial for us to know which markers might be important for a respective tumor, explains Dr. David Henderson, Principal Scientist in the Global Biomarker Department at Bayer HealthCare. Under the European Innovative Medicines Initiative (IMI), he is Coordinator of OncoTrack, a consortium of over 60 scientists from 19 institutions including eight of Europe s biggest pharmaceutical companies which is focusing on colon cancer, one of the most common tumor diseases in the industrial nations and one usually detected in the late stages. We already know a great deal about the development of the disease, and effective drugs do exist, but the diagnostics are

10 Medicine still too imprecise: we need better characterized biomarkers, Henderson says. To find them, researchers on the project examine tissue samples from both patients with advanced diseases and biobanks. Letter for letter, they decode the genome of the tumor sample and look for differences compared to the genetic sequence of healthy cells from the same patient. In addition, the researchers breed cell cultures from each tumor tissue sample and elaborate animal models. This allows us to test different drugs, for example, Henderson explains. Blood samples, cell size and shape, and other changes visible under a microscope are also part of the OncoTrack analysis. All data relating to a patient are collected and summarized in a computer model, also referred to as an in silico model. The more data we get, the better we can find the key sites and molecular patterns of different cancer cells, says Henderson. System biologists and bioinformatics specialists bring order to the mass of information This enormous volume of data must be processed, and help is coming from experts at the Max Planck Institute for Molecular Genetics (MPI) in Dahlem, Germany: With bioinformatics, we are getting the tremendous amount of data in order. As a result, it is easier to recognize correlations, says Henderson, explaining the benefit for Bayer HealthCare s research- Details by the batch: Ines Pieper (photo, bottom) prepares tiny, individual tumor samples just one millimeter in diameter, by joining them into a larger block. This way, several hundred tissue sections can be analyzed simultaneously. Biobanks Treasures from frozen storage For researchers, they are the closest thing to a treasure chest: biobanks store samples for future medical research. Tissue, urine (photo) and stem cells: these sources of patient information are preserved here in a deep freeze, sometimes for decades. A central database keeps track of the various disease stages and test results with which the samples are associated. Scientists worldwide depend on biobanks for medical progress. For instance, they hope to make new discoveries about biomarkers and their relevance for the different causes of a disease. Biobanks are the backbone of our research work in the field of personalized medicine, says Dr. Joachim Reischl, Bayer Health- Care. If a new biomarker is discovered, scientists can significantly accelerate research on diagnostics and therapy with the help of biobank samples and the corresponding patient data. 31 Bayer research _23

11 32 Experts in cell biology: a special sectioning instrument called a microtome (photo, top left) is used to prepare extremely thin slices of tissue. The organs embedded in paraffin are kept cool by sliding them directly into a water bath after slicing. In the next step, biology lab technician Sabine Jabusch (photo, bottom left) mounts the tumor tissue on a slide. In the meantime, other tumor cell cultures grow in an incubator and are inspected regularly by Dr. Christoph Schatz (photo, top). Dr. Karl Ziegelbauer (photo, above right), Head of Oncology / Gynecological Therapies Research at Bayer HealthCare, believes that the key molecular processes disrupted in patients suffering from cancer should be one of the main priorities of Bayer s scientific research work. ers. The company is funding a research position at the MPI, because the combination of informatics and biology is not only of great importance to the project s success, but also time-consuming. While we can sequence a tumor genome in two weeks, thorough data processing often takes up to six months, Henderson knows from experience. If everything goes according to plan, the participating researchers will soon know more about the progression of colon cancer, and can develop new biomarkers and therapies. Someday our data may even help us to predict a patient s response to therapy on the computer, Henderson says. The only thing required for this purpose is tissue samples. And that is precisely the problem: tissue samples are in short supply, because they necessitate a surgical procedure, as most organs are virtually inaccessible from the outside. For optimum therapy, however, biomarker analysis must be performed as early as possible, Reischl says. But surgery, on the colon for example, is hard on patients. Therefore, alternative sources for tumor characteristics are needed: The future of diagnostics is blood, Reischl reveals. He and his fellow researchers aim in the future to identify the most important biomarkers in tumor patients using only blood samples. Bayer HealthCare is partnering on the project with Prometheus Laboratories in San Diego, USA, a specialty pharmaceutical and diagnostics company. The idea sounds simple: cell biologists fish cancer cells that have separated from a tumor out of the blood using specially coated gold wire. These circulating tumor cells, or CTCs, provide us with a copy of the tumor, explains Dr. Thomas Krahn, Head of the Preclinical Biomarkers Group at Bayer HealthCare. Circulating tumor cells in the blood support personalized diagnostics The professional world is still debating how precise this copy is, but this much is clear: the more CTCs swimming in the blood, the larger and more threatening the tumor. Scientists worldwide are trying to find out which cells detach from a tumor and get into the blood and why. They may be the same cells that later give rise to metastases meaning sec-

12 Medicine ondary cancerous growths elsewhere in the body, says Krahn, describing the theory. Once researchers have solved this puzzle, the analysis of tumor cells in the blood could become part of routine diagnostics in doctor s offices. Bayer HealthCare researchers, however, not only want to improve the diagnosis of cancer diseases; they are also working intensively on new treatment methods. Unlike conventional chemotherapy or radiation, the new, customized methods among experts also referred to as targeted therapy focus their effect specifically on points of attack that are distinctive for cancer cells. We are studying key molecular processes that are abnormal in conjunction with cancer, explains Dr. Karl Ziegelbauer, Head of Oncology & Gynecological Therapies Research at Bayer HealthCare. At present, these targeted therapies are primarily given to patients with advanced tumor diseases, such as kidney, 33 Colon cancer: step by step into cell chaos DNA mutations in mucous membrane cells Specific mutations lead to new tumor characteristics Bayer research _23 Polyp: benign growth Malignant tumor Tumor with metastases Lymph nodes Blood vessels Tumor cells form metastases in the body Polyp Tumor Time The process by which a healthy cell develops into a cancer cell is insidious and often takes several years. Several genes must mutate before a benign growth in the colon, for example, transforms from a polyp into a malignant tumor. Which of these genetic changes is ultimately responsible for the uncontrolled growth can vary from patient to patient, and frequently remains unclear: every tumor has its own individual history. To be able to optimally treat a cancer disease, scientists in the OncoTrack research project are searching for key indicators, meaning biomarkers, which distinguish the tumor and point to potential targets for attack.

13 Cancer stem cells: promising targets Not all cancer cells are the same. Scientists have discovered that not all cells in a tumor display the same degree of malignancy. While most tumor cells divide only a few times, cancer stem cells, also called tumor-initiating cells, cause continuous growth in cancerous tissue. In addition, they can be responsible for a relapse. Standard therapy to date: cancer stem cells survive, tumor returns Tumor cells Cancer stem cell Relapse 34 Standard therapy in combination with therapy against resistant tumor cell type: long-term delayed / no relapse Tumor cells Cancer stem cell Chemotherapy and/or radiation Tumor eradication incomplete Conventional therapy Long-term delayed / no relapse Improved patient survival / cure Therapy against cancer stem cells Complete tumor eradication Cancer stem cells derive their name from their similarity to regular stem cells in the human body: they can self-renew and give rise to the very cancer cells that make up most of a tumor. In many cases, these simple cancer cells can be effectively treated with established drugs, and a tumor disappears. But it only appears so at first glance, because cancer stem cells are extremely resistant, says Dr. Peter Nell, Business Development and Alliance Management, Global Innovation Sourcing Department, Bayer HealthCare San Francisco. The few tumor-initiating cells frequently survive chemotherapy and radiation unharmed. After a time, these cancer stem cells reactivate (diagram above). At this point, they promote new, aggressive metastases that are hard to treat and ultimately fatal. Bayer researchers are therefore searching for therapies that attack these unusually resistant cancer stem cells. In partnership with California-based OncoMed Pharmaceuticals, they are working on new drugs that disrupt signal pathways believed to be crucial to the survival of cancer stem cells. Antibodies and other molecules may specifically block these signal pathways and halt the activity of cancer stems cells, Nell explains. OncoMed has done pioneering work in this field of research. The founders of the Californian company first discovered cancer stem cells in conjunction with breast cancer. They have since also been identified for leukemia and in intestinal, prostate and brain tumors. Scientists have great hopes for new therapeutic approaches, which could fill the gap in today s cancer treatment.

14 Medicine colon, lung, breast and liver cancer, as well as various forms of leukemia and lymphatic cancer, either alone or in combination with chemotherapy or radiation. Cancer stem cells also appear to have an important function in tumor biology, and are considered an attractive target for future therapies. But the work of the Bayer researchers is still in its infancy. New key molecular processes and signal pathways that govern the behavior of a cell are being discovered all the time around the world, Ziegelbauer says. They could play a role in tumor growth and be targets for future treatment strategies. One group of such important players and promising target molecules is the kinases. These protein molecules function like a switch, frequently controlling a cell s growth, Ziegelbauer explains. If a kinase is active in other words on the cell can divide. Deactivating these proteins interrupts the signal chain. The nucleus doesn t receive a signal to divide, Ziegelbauer concludes. In cancer cells, key switching stations have often stopped working properly. Some kinases have mutated and are therefore permanently active. As a result, the cell divides continuously. Ziegelbauer and his team are searching for new active substances to suppress the activity of the kinases and thus interrupt signal transmission. In the best case, the degenerated cell even dies, says Ziegelbauer. Various research teams at Bayer HealthCare are currently testing several substances which could act as kinase inhibitors and stop the growth of different types of cancer. In addition, several promising drug candidates are already under clinical testing. But kinase inhibitors are only one group of new therapeutic drugs, which are to become the standard in the new age of personalized medicine. Another important group that likewise moved out of the laboratories of the molecular medicine specialists several years ago and into clinical testing is the monoclonal antibodies (see also research 22, Double whammy ). They attach to a specific molecular structure on the surface of a cell and can alter or block its function. Today they are also being used as a means of transporting cancer drugs, because an antibody can reliably smuggle an active substance to the right place inside a cell. This way, we can force a tumor cell to commit suicide, for example, explains Dr. Bertolt Kreft, Head of the Immunotherapy & Antibody-Drug Conjugates Department in Bayer HealthCare s oncology research. Inseparable partners: personalized diagnostics and targeted therapy Whether antibodies, kinase inhibitors or other customized drugs, biomarker diagnostics and targeted therapy are becoming inseparable partners in personalized medicine. These days, we always try to find a matching biomarker for every drug in our oncology pipeline, says Dr. Joachim Reischl. Licensing authorities in the United States and Europe also attach great importance to this combination, as it is poised to enhance the efficiency of tomorrow s medical care. In the race against lifethreatening diseases, testing a series of different therapeutic approaches costs the patient valuable time, Reischl states. To speed things up in the future, the results of cancer research must move as quickly as possible from the laboratory 35 Bayer research _23 Future diagnostics: Dr. Antje Stratmann and Dr. Thomas Krahn (photo, left) inspect a specially coated gold wire, which may help in diagnosing tumor tissue by fishing cancer cells directly out of the blood. Special analytical tests determine later on whether the tumor cells respond to a new therapy. For this purpose, Irene Hofer (photo, bottom) scans lung cancer samples stained with different dyes.

15 to practical application. Scientists want to achieve just that by way of translational medicine. This field at the interface between preclinical research and clinical development brings together interdisciplinary teams of researchers. Many cancer clinics already specialize in this new approach. At integrative cancer centers around the world, doctors, scientists and computer experts work in concert to examine the clinical picture of a disease individually, in each and every patient, says Dr. Monika Lessl, Head of Alliance Management, Global Innovation Sourcing. Translational medicine specialists not only accelerate the process from molecule identification to medicinal drug for a new targeted cancer therapy, they also think, according to Lessl, in reverse: Newly gathered clinical data can be used again for new research hypotheses. Just as biomedical research takes place around the globe, personalized medicine is intended to reach a large number of patients worldwide as quickly as possible. Researchers at Bayer HealthCare are therefore working together with colleagues in Singapore, for example, on specifically Asian tumors such as liver cancer. Lessl is responsible for managing the cooperation projects with a total of six institutions in Singapore. The Singapore Collaboration, as it is known, helps to advance research on Asian tumors for personalized medicine. Global research: tumors in Asians often have different characteristics than in Europeans However, Lessl says, extensive expertise in the field of translational medicine was only one of the criteria for deciding to partner with the institutions in Singapore. The island state is currently viewed in general as one of the foremost biomedical 36 Targeted cancer therapy: blocking signal pathways X Antibody binds EGF receptor Kinase inhibitors prevent signal transmission X DNA Cell survives Tumor metastasizes Cell divides Blood vessels grow New cancer therapies target key molecular processes in a cell that are abnormal in a tumor. Take colon cancer, for instance: virtually all tumor cells develop receptors for growth factors (EGF receptor) on their surface. When the EGF growth factor binds there, it triggers a cascade of signals relayed from the cell membrane all the way to the DNA inside the nucleus. The degenerated cells receive a signal to survive and continue dividing. In addition, blood vessels grow into the tissue. The tumor is now capable of metastasizing. Therapies for colon cancer are designed to disrupt the signal pathway at various points. An antibody, for instance, binds the EGF receptor and prevents its activation. Other active substances block specific protein molecules (kinases) involved in signal transmission.

16 Medicine Singapore collaboration Research in and for Asia The projects in the Singapore Collaboration concentrate primarily on biomarker analysis and new therapies for the tumors typical in Asians: stomach and liver cancer. Together with doctors and molecular biologists, we are examining corresponding cell cultures and animal models for signal pathways that are activated by the substances we have under development, reports Dr. Monika Lessl, Head of Alliance Management, Global Innovation Sourcing. In a project with the National University of Singapore, for example, a team of researchers is tracking down mutations and signal pathways that distinguish Asian from European cancer cells. They want to find out if substances under development have an effect on stomach cancer, for instance. A clinical Phase I study with a new active substance for treating intestinal cancer is currently being conducted by Professor Boon Cher Goh (photo) at the National University Hospital, Singapore. The researchers here likewise want to identify biomarkers that help divide patients into different groups. In cooperation with the Singapore Bioimaging Consortium, diagnostic imaging methods are also being improved to visualize differences in the metabolism of healthy and degenerated cells. With the help of Positron Emission Tomography (PET), nuclear medicine specialists can trace how specific substances are distributed in the body. Radioactively tagged sugar, for example, accumulates in significantly higher levels in cells showing uncontrolled growth than in healthy cells, thereby indicating the areas in a patient s body infected by tumor cells. 37 Bayer research _23 research hubs in the Asia region. Through the arrangement, Bayer researchers also learn more about specific tumor characteristics in Asian cancer patients. Tumors in Asians often develop in an entirely different manner than those in European cancer patients, Mumberg says. The first time scientists noticed this was in the analysis of a candidate therapeutic agent that had shown disappointing results in clinical studies on patients with lung tumors. Only one group of nonsmokers yielded very good results: women of Asian origin. After further analysis, the researchers discovered a specific gene mutation that made these Asian women highly sensitive to the new therapy. The findings were a major success: Today, only patients displaying this mutation are given the drug, Mumberg says. Molecular medicine paves the way to improved therapeutic success The more experience researchers at Bayer HealthCare acquire worldwide with the medicine of the future, the clearer it becomes: Even if some substances show only a minor effect in the majority of patients, they can be very effective in individual cases and even save lives, Mumberg emphasizes. In short, molecular medicine is helping to give the clinical picture of a disease a much more personalized description. And that increases the efficacy of active substances, because the molecular findings provide new information: doctors more frequently recognize aspects unique to an individual, such as a specific enzyme that breaks down a drug more quickly than usual. Indicators of this kind are critical when it comes to determining drug doses and tolerance, Mumberg says. In the future, personalized medicine will not be limited to tumor therapies. Scientists worldwide are starting to understand the molecular patterns of other diseases as well, and searching for their characteristics. In the future, a diagnosis will be supported by more than just an in-depth consultation with the patient, lab work and x-rays: biomarkers may ultimately deliver the most crucial information on a patient s disease profile, thereby guaranteeing the more efficient use of modern medicine and, above all, improved therapeutic success for each and every patient. Further information on this topic