Women in Science: Jewel Plummer Cobb (1924-2017)

From an early age, Jewel Plummer Cobb understood the significance of education, which is clearly reflected in her family history. Her paternal grandfather was a freed slave and graduated from Howard University in 1898 with a degree in pharmacy. Frank Plummer, her father, attended Cornell University and earned his M.D. from Rush Medical College in Chicago. Cobb’s mother, Carriebel Cole Plummer, studied at the Sargent School of Physical Training in Cambridge and taught physical education and dance.

As a young girl growing up in Chicago, Cobb was acutely aware of the racial injustices in the segregated education system. Around the country, gerrymandered school districts forced black children to attend overcrowded, underfunded schools, and Chicago was no exception. In fact, when Cobb attended Englewood High School, the school had to run on double shifts in order to accommodate the increasing number of black students. 

In spite of these discriminatory policies, Cobb excelled in her studies and took part in a special honors-track program focused on science. She decided to study biology and started undergraduate courses at the University of Michigan in the fall of 1941. Cobb was eager to move to Ann Arbor and did not expect to feel out of place in her new environment. The University of Michigan had a sizable black student population at the time, and Cobb’s family had spent many summers vacationing in northern Michigan.

Of course, the realities of being a black woman at a largely white university and town in 1941 were quite different. Cobb was not allowed to live in a dormitory and was consigned to off-campus housing reserved for black students. Many of the popular restaurants and bars did not serve black patrons. Social life on campus was also limited because most sororities and fraternities did not accept black students. As a result, Cobb felt isolated from the normal college experience.

After a year at Michigan, Cobb transferred to Talladega College, a historically black college in Alabama. The Dean of Women at Talladega was a family friend and suggested their science program after hearing about Cobb’s concerns at Michigan.

It turned out to be a perfect match. Although Talladega didn’t have the resources of the Big Ten university, it had something else that Cobb was desperately lacking at Michigan: mentors. Her teachers at Talladega were enthusiastic about her potential in biological research and encouraged her to apply to graduate school. She completed her coursework at Talladega in two years and graduated in 1944 with a B.A. in biology.

On her teacher’s recommendation, she applied to the New York University graduate program in biology. Although Cobb was accepted to the program, they rejected her application for a teaching fellowship. Undeterred, Cobb went to NYU to personally convince the administration, and she was ultimately awarded the fellowship to support her continued training in biology.

She was at NYU for six years, earning her master’s in 1947, and her doctorate in 1950. For her doctoral thesis “Mechanisms of Pigment Formation,” she characterized tyrosinase, an enzyme required for melanin synthesis. Melanin is the pigment underlying variations in human skin color. More melanin granules lead to deeper skin tones, while a loss of melanin causes albinism. Cobb studied the mechanisms of tyrosinase in vitro, testing its ability to synthesize pigment granules from different substrates. This research would form the basis of Cobb’s lifelong interest in melanin and skin cancer.

After defending her thesis, Cobb earned a two-year grant from the National Cancer Institute and began her postdoctoral fellowship at the Harlem Hospital Cancer Research Center. At Harlem Hospital she worked under Louis Tompkins Wright and collaborated with Jane C. Wright, whose research I’ve covered in a previous article. During her fellowship, Cobb gained extensive knowledge of primary human tissue culture, a burgeoning field in the 1950s. Cobb was particularly successful in culturing cancer cells directly from patient biopsies, which she used to study the effects of different chemotherapy drugs on cellular morphology, migration, and growth.

In 1952 Cobb founded her own laboratory at the University of Illinois Medical School. Her lab was the first tissue culture based lab at the medical school, as very few scientists in the early 1950s were trained in these techniques. At Illinois, she was able to combine her two passions into one research program: the study of melanin and skin pigmentation in cancer development.  In 1954 she moved her lab back to Harlem Hospital, which soon became a part of NYU’s Post-Graduate Medical School.

Once back at Harlem Hospital, Cobb began working on some of her most exciting and innovative research, as part of an ongoing collaboration with Jane Wright. Wright studied the effects of chemotherapeutic agents on various cancers in vivo. In parallel, Cobb cultured cells from the tumors of the same patients and studied the phenotypes following in vitro chemotherapy treatment. These experiments were some of the earliest forms of translational medicine, as both Cobb and Wright realized that the in vitro results might be used to predict beneficial treatments for specific patients and cancer sub-types.

Their research was first published in the 1957 New England Journal of Medicine paper, “Investigation of the relation between clinical and tissue-culture response to chemotherapeutic agents on human cancer.” The manuscript details the clinical and tissue culture-based observations of 40 patients, representing 18 distinct types of cancer. Of the 40 cases, 26 reacted similarly to in vivo and in vitro treatments, meaning that the tissue culture-based system predicted 65% of patient responses.

Building on this success, Cobb and Wright’s 1961 study in Cancer Research profiled the in vitro sensitivity of 188 different patient tumor samples to a panel of chemotherapy agents. Importantly, Cobb also studied benign tumors and healthy non-tumor tissue, controls that were not routinely performed in early tissue-culture studies. Although contemporary scientists would consider the inclusion of non-cancerous tissue an essential part of this experiment, in the 1960s it was exceedingly difficult to establish human cell cultures. Cancer cells were easier to grow because many cancers contain mutations that predispose to cell proliferation; healthy cells were an entirely different specialty. This is a detail easily lost in telling Cobb’s story but highlights her genius in developing modern tissue culture.

Cobb also published research on mouse models of melanoma, utilizing a Jackson Laboratory mouse line with an increased incidence of skin cancer. Using this model, she found that deeper pigmentation of skin cells protects them from radium and X-ray treatments. Cancer cells with more melanin survived in vitro radiation experiments, while lightly pigmented cells from the same tumor did not. This is the first evidence for the UVA/UVB shielding properties of melanin, which explains the large disparity in skin cancer rates among people with dark and light skin.

During this time, Cobb moved between universities, leaving NYU in 1960 to accept a full professor position at the all-women Sarah Lawrence College in Bronxville, N.Y. Cobb enjoyed teaching these young women about experimental science and inspired several of them to attend graduate school.

In 1969 Cobb became Dean of Connecticut College in New London, Conn., and began creating dynamic educational programs that encouraged minority and women students to pursue STEM careers. She started one of the first post-baccalaureate programs for minority students, which supported college graduates wanting to enter post-secondary medical training. The post-bac provided mentoring and coursework that made it possible for more minority students to apply and be accepted to medical and dental schools.

Cobb went on to become Dean of Douglass College, the women’s division of Rutgers University in New Brunswick, New Jersey, in 1976. While at Douglass she made the difficult decision to conclude her academic research, although she continued to teach courses and establish tissue culture laboratories. She realized that her greatest role was as an advocate for young minority students, who needed someone like her in the higher ranks of university administration.

Part of her activism was speaking out against the entrenched inequalities she perceived across multiple fields of science. In 1979 Cobb penned one of her most famous pieces, “Filters For Women in Science,” which outlines both the subtle and flagrant ways society discourages young women from contributing to scientific progress. In 2018, every one of her points still rings true. Cobb outlined several ways to combat this sexist narrative in her article, although few of these suggestions were implemented at the time (or since).

From this point onward, Cobb made it her mission to increase retention of women and underrepresented minorities in science. In 1981, Cobb took over as President of California State University, Fullerton, becoming one of the first black women to head a University in the United States. During her nearly 20-year tenure at Fullerton, Cobb was instrumental in the construction of a new laboratory center and computer science and engineering buildings. She oversaw the transition of Fullerton from a commuter college to a large state university and sought funding for on-campus housing to accommodate the growing student population.

Cobb continued to advocate for black students, establishing pre-medical and pre-dental programs similar to the ones she spearheaded at Connecticut College. She increased diversity on the Fullerton campus within the student population and faculty. Cobb also acknowledged that many of the inequities in STEM education occur before students ever arrive at college. As a result, she formed a faculty tutor program, to support students that were struggling in math and science classes.

While at Fullerton, Cobb also became the first black woman appointed to the National Science Board, a committee that supervises the National Science Foundation (NSF). She took her activism directly to the NSF, calling for new strategies to engage underrepresented minorities and women into the sciences. Many of the educational programs in place today are a result of her consistent demands for equal representation in government-sponsored research.

In 1990, Dr. Cobb retired from Fullerton and became a Trustee Professor at UCLA. At UCLA, she worked with the Sothern California Science and Engineering ACCESS Center and Network (SOCAL CAN) and the Science Technology Engineering Program (STEP), programs that aim to increase the number of poor and minority students in college and STEM careers. Specifically, she led the 2001 California State University ASCEND projects aimed at engaging youth with STEM activities and career opportunities.

Cobb passed away from complications of Alzheimer’s disease on January 1, 2017. During her career, Cobb received multiple awards and honorary doctorates, including the National Academy of Sciences Lifetime Achievement Award in 1993.

In a 1990 interview with the Association for Women in Science, Dr. Cobb was asked how she would like to be remembered. She replied simply,

“I think I’d like to be remembered as a black woman scientist who cared very much about what happens to young folks, particularly women going into science.”

Ellen Elliott, Ph.D., is a postdoctoral fellow at The Jackson Laboratory for Genomic Medicine in Farmington, Conn. Ellen works in the laboratory of Adam Williams, Ph.D., where she is studying the function of long non-coding RNAs in TH2 cells and asthma. Follow Ellen on Twitter at @EllenNichole.