SUMMARY REPORTS OF EXCHANGE SCIENTISTS

(1) Saburo Sone
Third Department of Internal Medicine The University of Tokushima School of Medicine

SPONSOR AND HOST INSTITUTION:
Dr. Isaiah J. Fidler, MD Anderson Cancer Center. University of Texas
Dr. Lance Liotta, National Cancer Institute
Dr. Avraham Raz, Michigan Cancer Foundation
Dr. Michael Lotze, Pittsburgh Cancer Center
DATES OF VISIT: November 1-16, 1995

SUMMARY OF ACTIVITIES:
Problems associated with chemotherapy of lung cancer are distant metastasis and development of multidrug resistance. Much efforts have been paid for development of therapeutic modalities to overcome such problems. Little is known, however, about detailed mechanisms of metastasis and drug resistance of lung cancer cells, because appropriate experimental models which reflect clinical situations have not been available yet. Recently, we have established a model of metastasis of human lung cancer (SCLC and non-SCLC) cells in NK-cell deficient SCID mice in which lung cancer cells formed distant metastasis to lymphnodes, liver and kidneys 6 to 8 weeks after their iv injection. Interestingly, no metastasis occurred to lungs. Transduction of genes of cytokines (e.g.. M-CSF) in lung cancer cells was found to be effective in controlling their distant metastasis. Anti-MDRI antibodies showed potent therapeutic effect on metastasis of MDR human lung cancer cells. We have been extensively studying to develop therapeutic modalities for control of human lung cancer by using combination of cytokine gene transduction with antibodies for MDRI or GM2 ganglioside expressed on human lung cancer cells. In this program I gave a seminar entitled “Cytokine Gene Therapy of Lung Cancer,” at Michigan Cancer Foundation and at Pittsburgh Cancer Institute, respectively. There I exchanged valuable information about possible approaches to develop immunogene therapy of human lung cancer. Dr. M. Lotze (Pittsburgh) showed how to perform clinical trial with cytokine gene therapy for cancer. I visited Drs. L. Liotta and S. Stevenson at NCI in NIH and Dr. I. J. Fidler at MD Anderson Cancer Center. Subjects which I discussed were l) availability of appropriate model of human cancer metastasis in SCID mice and its evaluation, 2) search of new antigens expressed on metastatic cancer cells and possible approach of the antibody-directed molecular targeting, 3) development of carrier vehicles to deliver cytokine gene into the tumor growing ite and vector system to carry cytokine gene and 4) problems associated with clinical application of cytokine gene therapy for cancer and methods to overcome them. Dr. Liotta addressed importance of MMP in tumor invasion, and its inhibitor should be useful for treatment of tumor metastasis. They suggested that our model of human lung cancer metastasis in SCID mice could be used or such a study. Dr. Fidler gave several advice that microenvironment in target organs where human lung cancer cells could metastasize should be elucidated from a view point of host-to-tumor interaction, because tumor cells grow or regress in a microenvironments under complexity of autocrine and/or paracrine network of cytokines. By participating this exchange program, I learned and obtained a lot of new information and ideas to advance my research projects in future. Particularly, I found that study on the development of immunogene therapy for human lung cancer metastasis should be based on basic understanding of detailed mechanisms responsible for metastasis of human lung cancer. For this purpose we agreed on collaborative study between my group and Dr. Fidler’s group.



(2) Nagahiro Saijo
Pharmacology Division, National Cancer Center Research Institute

SPONSOR AND HOST INSTITUTION:
Dr. Bruce E. Johnson Lung Cancer Biology Section, NCI, NIH
DATES OF VISIT: April 4-19, 1995

SUMMARY OF ACTIVITIES:
The purposes of this visit could be divided to those major topics. The first is to understand how the peoples of US decide to start the clinical trials based on the preclinical trials and how they evaluate the NCI-supported protocols. The second is to discuss with the pharmacokinetic and pharmacodynamic studies of anticancer drugs. The third is further to promote the exchange of researchers of the United States and Japan. I mainly stayed at Dr. Bruce Johnson’s office, NCI Medical Oncology Branch and visited CTEP, FDA and Johns Hopkins Oncology Center. I also attended the Third International Workshop of Pharmacokinetics and Pharmacodynamics of Anticancer drugs, which was held at Irvington. Virginia. In NCI, the director has just changed to Dr. Klausner and new positions of other researchers will be decided on October. Therefore, everybody is very anxious about the fate of his laboratory. The treatment area has already been divided into extramular and intramular activities. The biggest difference between Japan and USA in the development of new drug or new treatment method exists in the system of preclinical and clinical trials. I felt that the money from the government should be more paid for the establishment of the efficient systems for new drug development in Japan. It was amazing that 25% of anticancer drugs are produced preclinically and 100% of the drugs are developed clinically in NCI. The decision committee which decide the entry to clinical trails from preclinical trials is important. However, it is rather difficult for us to have such kind of committee because there are only few talented persons in Japan. Dr. George Curt suggested that it is important for us to send the doctors of this area for about one year to improve this situation. At CTEP they mainly review the protocols which was sent from collaborative study groups. Their important activity is to obtain the up-to-date data of the study groups and distribute them to the participants. They said that the comments by the CTEP are usually very trivial, however, the merit of the system is to access to the results of ongoing protocols. Interestingly it depends on the scientific and political power of each investigator to obtain the interesting drugs for clinical trials even in USA. I need to stress again that there are many opportunities for them to have discussions among researchers of pharmaceutical companies and FDA, which means that there is no communication defect among them. It is extremely important for us to have such kinds of opportunities. At Johns Hopkins Oncology Center the situations were a little bit different. Majority of the money were paid for basic research works and the clinical doctors were complained of the current situation. The meetings with peoples of FDA also provided extremely important information. All the clinical protocols are reviewed by the members of FDA which has a lot of medical oncologists as a staff. The review of FDA dose not mean the approval but the permission of the start of clinical trials. This mechanism is just incorporated in Japan for the evaluation of the clinical trials of phase after the approval of new drugs by MHW. It is strongly suggested that this activity should be incorporated into the evaluation of the protocols of phase or studies for new drugs. Third International Workshop on pharmacodynamics of Anticancer Agents were held at Irvington, Virginia from September 13 to 17, 1995. This workshop was organized by Dr. Merril Egorin. Professor of Medicine, Maryland Cancer Center. The workshop was divided to New Modeling Strategies, Minimally Invasive Evaluations of PK/PD, Integration of in vitro Testing into PK/PD Studies, Selected Aspects of Drug Metabolism and Clearance, Measurement of Specific Therapeutic Target, Adaptive Control Dosing Strategies and PK/PD Aspects of Specific Drugs. I was a Modulator of last session. The meeting was well organized and update information of clinical pharmacologists were obtained. In the meeting other participants from Japan were Dr. Sasaki. National Cancer Center Hospital East and Dr. Tanigawara, Kobe University. I felt that more young doctors should actively participates this kind of meeting. For that purpose, the funding should be improved. I discuss with several doctors on the possible visit to Japan and the sending of young doctors to the United States. Dr. Susan Arbuck of CTEP and Dr. Piantadosi agreed to come over to Japan. The acceptance of young fellows from Japan is right now rather difficult in NCI because of the situations described at the beginning. However, I discussed with the possibilities with several doctors and it was clearly shown that they could accept them if the funding from Japan will be obtained. I and young doctors will continue to do the effort to obtain such supports in order for the further collaboration of USA and Japan.



(3) Jun Yoshida
Department of Neurosurgery Assistant Professor

SPONSOR AND HOST INSTITUTION:
Dr. Edward H. Oldfield National Institutes of Health, Surgical Neurology Branch, Chief
DATES OF VISIT: February 2-5-March 10, 1996

SUMMARY OF ACTIVITIES:
Malignant glioma (anaplastic astrocytoma and glioblastoma) is a pilrcnchyma1 tumor in the brain of the central nervous system (CNS) that aggressively infiltrates into the surrounding normal brain tissue. Total resection of tumor by surgery is impossible, and even if patients receive extensive surgical resection of tumor and postoperative adjuvant therapy of radiation and immunochemotherapy, average survival time is less than 2 years. Nevertheless, this malignant glioma has important features as a candidate for gene therapy. The brain is a closed cavity separated from the general circulation system by the blood-brain barrier, and it has been noted to be an immunologically privileged site with no lymphtltic system. Normal brain cells of glid and neuron are relativcly quiescent compared to the tumor cells. Furthermore, the glioma arising from a glia is a localized tumor in the CNS with no extra-CNS merastasis. Since the first gene therapy was started on 14 September 1990 in the United States for a patient with severe combined immunodeficiencies, various human gene therapies have been proposed and carried out. Target diseases of this therapy are now expanding from congenital metabolic disorders to malignant neoplastic tumors, which cannot be cured by existing treatments. Three approaches of cancer gene therapy are proposed: repairing an oncogene or suppressor oncogene transduction of 11 toxic gene into tumor cells, and augmentation of a gene that activates tumor immunity. In 1992, for patients with malignant brain tumor, a team of National Institutes of Health (the United Statcs) biologists and neurosurgeons started a remarkable new form of treatment: molecular neurosurgery based on gene therapy. Mouse cells were genetically modified by inserting a retroviral vector carrying a herpes gene coded for thymidine kinase. When the mouse cells were injected directly into a brain tumor, they start pumping out copies of the retroviral vector, which infect near by tumor cells. The infected tumor cells now produced herpes simplex thymidine kinase (HS-tk). Iaying themselves open to attack by intravenous injcction of thcantiviral drug ganciclovir. Wc have developed novel cationic liposomcs with high transfection cfh~cicncy and low cytotoxicity that permit using thcsc for in vivo gene transfer. Our liposomes are multilamellar vesicles (MLV) prepared by a simple procedure with N-(-trimcthyl ammonioacetyl)-didodecyl-D-glutamata chlorida(TMAG), dilauroyl phosphatidylcholine(DLPC), and dioleoyl phosphatidyl ethdnolamine (DOPE) in a molar ratio of 1:2:2. The liposomes entrapped expression vectors of plasmids and transfected them into the cells. In our sysetem, the gene was transfected mainly by endocytosis of liposomes and expressed predominantly in the proliferating cells. The expression rate was generally 10-20% in cultured neoplastic cells in vitro. In 1988, we started basic study for the evaluation of gene therapy toward malignant brain tumors by means of DNA/liposomes and cytokine genes were selected for this study. Because Interferon (IFN) and tumor necrosis factor (TNF) are produced in human glioma cells and known to act a negative growth factor to them: the growth of glioma is suggested to be deeply related to these autocine or paracrine cytokines. Furthermore, these cytokines modulate the expression of the cell-surface antigens, including major histocompatibility complex (MHC) antigens and cell adhesion molecules, thus providing a potential regulatory mechanism for local immune reactivity. In our study, glioma cells transfected IFN-TNF-genes produced and secrered thc cytokines continuously. resulting in the incluction of MHC antigens and intercellular adhesion molecule- 1(ICAM-1) on the surface of glioma cells. Our in vitro and in vivo experiments have confirmed that cytokine gene transfer by means of DNA/liposomes has promising clinical application and we are now submitting our gene therapy protocol toward malignant glioma with interferon- to Institutional Review Board of Human Gene Therapy. In my this situation, I and my co-investigator, Dr. Wakabayashi, visited five institutes in USA; National Institutes of Health, University of Pittsburgh, Ludwig Institute of Cancer Research in Memorial Sloan Kettering Cancer Center, University of California San Francisco, and Georgetown University as US-Japan cooperative cancer research program. We met more than 20 Scientists who are doing basic and/or clinical studies for the development of human cancer gene therapy and new therapeutic modalities of malignant brain tumors, and we talk each others about present and future direction of human gene therapy. Fruitful discussion and close relation of both countries in this field could be obtained and they will provide us progress in the treatment of cancer patients in Japan. On February 26-27, we visited National Institutes of Health (NIH) and met with Edward H. Oldfield, M.D. (Chief, Surgical Neurology Branch), Michael Blease, M.D. (Chief, Clinical Gene Therapy Branch), Steven Rosenberg, M.D. (Chief, Surgical Branch), and Jay Ramsay, M.D. (Research fellow, Clinical Gene Therapy Branch). Since 1990, many patients with lung cancer, melanoma, or brain tumors were treated with suicide gene therapy or cytokine gene therapy by using retorovirus or adenovirus vectors. We could contact detail results concerning efficacy and side effect of human gene therapy. We met and talk with patients received the therapy. Furthermore we could discussed with neuro-oncologists in NIH about new modalities of diagnosis and treatment of malignant brain tumor; functioning image of brain and immunotoxins. I presented special lecture titled “A prelude to cytokine gene therapy for malignant glioma in Japan” at Surgical Neurology Branch Seminar. On February 28, we visited Georgetown University and met with Robert L. Martuza, M.D. (Professor and Chairman. Dept. of Neurosurgery). We discussed with him and his staff about basic research work of gene therapy with defective herpes virus toward brain tumors. On February 29 and March l. we visited Pittsburgh University and Center for Biotechnology and Bioengineering. We met with Michael T. Lotze (Professor and Director. Surgical Oncology), Hideaki Tahara (Assistant Professor, Surgical Oncology), Joseph Glorioso (Professor and Director, Human gene therapy center). Leaf Huang, and Dade Lunsford (Professor, Dept. of Neurosurgery). They explained us how to organize Pittsburgh Human Gene Therapy Center and how to produce virus vectors (retorovirus, adenovirus, and_ herpes virus) and non-virus vectors (liposomes) in the Vector Core Facility. They also showed their preclinical and clinical works of cancer gene therapy with IL-4 or IL-12 genes. On March 3, we visited Memorial Sloan Kettering Cancer Center and met with Lloyd Old M.D. (President, Ludwig Institute for Cancer Research). We could discuss basic and clinical study of immunotoxins for the treatment of cancer patients. On March 7 and 8, we visited University of California, San Francisco and met Dennis Dean, Ph.D. (Professor and Associate Director, Brain Tumor Research Center), Philip Gutin, M.D. (Professor of Neurosurgery). They showed clinical results of suicide gene therapy with HStk gene/ganciclovir toward malignant glioma and we could discuss efficacy and present limitation of gene therapy as a new modality of adjuvant therapy for brain tumors.