Memorial for Charles Kasper

Charles Boyer Kasper, Ph.D.
April 27, 1935 – September 5, 2023

 I am writing to let you know the sad news that our respected colleague Professor Emeritus Charles B. Kasper passed away on September 5, 2023, in Appleton, WI. He is survived by his wife of 66 years Mary Jean, children Lynda (Dave), David, Jenette (Bradd), and JoAnna (Matt), seven grandchildren, and five great-grandchildren. You may view his obituary at

Throughout his long career at the McArdle Laboratory for Cancer Research, Dr. Kasper led an outstanding research program that continued to provide novel discoveries about basic aspects of cell biology. He will be remembered for his gentlemanly demeanor, deep convictions, intellectual rigor, and his lasting contributions to the field of chemical carcinogenesis.

Born and raised in Illinois, Charles B. Kasper attended the University of Illinois-Chicago earning a degree in Pharmacy in 1958. He came to the University of Wisconsin-Madison for his graduate studies with Dr. Harold F. Deutsch in the Department of Physiological Chemistry, receiving his PhD in 1962. Dr. Kasper was awarded an NIH Fellowship for his postdoctoral studies in the laboratory of Dr. Emil Smith, first at the University of Utah and then at UCLA. Recognized for his knowledge of protein chemistry, he was soon promoted to Assistant Professor at UCLA.

Around that same time Harold P. Rusch, the Director of the McArdle Laboratory for Cancer Research (also the Department of Oncology) at the University of Wisconsin-Madison, became interested in hiring a new faculty member who had a background in protein chemistry/immunochemistry to study the possible differences in the membranes of normal and neoplastic cells. After successful recruitment, Dr. Kasper joined the faculty at the McArdle Laboratory in 1965.

Dr. Kasper’s early studies led to the isolation, purification, and characterization of nuclear envelope from rat liver cells. For the first time highly purified nuclear envelope was made available for detailed chemical and biochemical studies. This resulted in a molecular characterization of the envelope from normal and tumor cells that identified specific alterations in the tumor membrane. Biochemical studies also revealed that the nuclear envelope possesses those enzymes responsible for the metabolic activation of chemical carcinogens to their ultimate reactive forms. The localization of these enzymes on the nuclear surface suggests that the crucial site for activation of carcinogenic substances that react with nuclear DNA is the envelope. Dr. Kasper’s research group also demonstrated that the nuclear envelope associated enzymes are not induced by phenobarbital as are the corresponding enzymes in the endoplasmic reticulum. Hence, the metabolic regulation governing the synthesis and/or insertion of these enzymes into the nuclear envelope matrix differs from that observed for the microsomal membrane.

Dr. Kasper continued to successfully use a variety of approaches as a means of solving problems in contemporary biology. He focused his research on developing an understanding of the structure-function relationships and biochemical regulation of enzymes important in the metabolism of chemical carcinogens, namely, epoxide hydrolase, NADPH-cytochrome P-450 oxidoreductase, and the cytochromes P-450. The mixed-function oxidase system and associated enzymes represent a major line of defense between man and his environment. These enzymes are localized in the nuclear envelope and endoplasmic reticulum and are responsible for the early metabolic steps in the detoxification of xenobiotics as well as the metabolic activation of certain chemical carcinogens. Consequently, the response of the cell to various foreign compounds and the eventual fate of the cell depend to a large extent upon the activity level of these key enzymes.

Dr. Kasper made seminal contributions to our knowledge of the control, regulation, expression, structure and mechanism of NADPH-cytochrome P450 reductase. His laboratory identified R597 in the FAD binding domain that accounts for the differential binding energy of NADPH over NADH. They also identified two clusters of acidic residues in the FMN binding domain that play a role in interactions with the external electron acceptors, cytochrome c or P450.

For more than 36 years, Dr. Kasper carried out first-rate basic research concerning drug-metabolizing enzymes and the roles they play in mammalian health. During this time, he was continuously funded through competitively awarded research grants from the NIH, and his work resulted in nearly 100 peer-reviewed publications.

Dr. Kasper also made significant contributions to the teaching and service missions of the University and the Department of Oncology. He mentored many undergraduate, graduate, and medical students and postdoctoral trainees who went on to productive careers in industry and academia. He was a long-time instructor in the graduate-level course Oncology/Toxicology 750 and taught for many years in the neoplastic diseases course for medical students. He was a member of the American Association for Cancer Research and the American Society for Biochemistry and Molecular Biology, served on various advisory committees and study sections for the American Cancer Society, and was a member of the editorial boards of the scientific journals Chemical-Biological Interactions and the Journal of Biological Chemistry for several years. A strong promoter of rigorous laboratory safety standards, Dr. Kasper chaired the Safety Committee for the Department of Oncology for over 20 years.

Although Charles dedicated his professional life to cancer research, his devotion to faith and family was paramount and brought him great happiness. Shortly after his retirement from the University in 2001, Charles and his wife, Mary Jean (Jeanne), moved to Appleton, WI to be closer to their children and grandchildren. An avid outdoorsman, he especially enjoyed their annual winter trips to St. George, Utah during his many years of retirement.

I wish to thank Bette Sheehan for her effort in helping put this tribute together.
Paul F. Lambert, Director, McArdle Laboratory for Cancer Research