Optimizing Recombinant Protein Production in Cultured Mammalian Cells

This blog is about my research as a Professor of Nanobioscience (SUNY Polytechnic Institute, Albany, NY USA) and Fulbright Visiting Scholar at the NICB, DCU (Sept.-Dec. 2017) and which is summarised in the below video of my talk “Understanding the factors that control productivity in CHO cells” which I delivered in the NICB on Tuesday 3rd October 2017.



A little bit about biotechnology and biopharmaceuticals

Biotechnology and the biopharmaceutical industry are a global enterprise, with academic research and industrial manufacturing taking place in much of the developed world. What we mean by biopharmaceuticals are therapeutic compounds produced by living systems, organisms, or enzymes and most commonly, therapeutic proteins produced by cultured animal cells or bacteria. If you know someone who had a heart attack or stroke and received tissue plasminogen activator (t-PA), or someone with breast cancer who was treated with Herceptin, these are examples of biopharmaceuticals. There are currently over 200 approved biopharmaceuticals on the market today and they represent approximately 25% of all new drug approvals. These drugs provide revolutionary, life-saving and life-changing treatments for a variety of conditions including cancer, autoimmune diseases, infectious diseases, and clotting disorders. Despite huge advances since the development of the first recombinant protein drug, human insulin, in the 1970s, many scientific and technical challenges remain as we create new types of therapeutic molecules and attempt to reduce the costs of these drugs to make them available to the developing world.

A little about me and what I do

I am a Professor of Nanobioscience at SUNY Polytechnic Institute, in Albany, New York. The focus of my research program is in mammalian cell biotechnology, primarily the use of cultured mammalian cells to produce therapeutic proteins (primarily antibodies) and carbohydrates (particularly Heparin and Heparin-like molecules). Unlike traditional pharmaceuticals (e.g. aspirin, Tylenol), biopharmaceuticals cannot be easily synthesized in the laboratory. Instead, the cellular machinery of cultured cells is “hijacked” to produce the desired compounds, using the tools of modern molecular biology. While this is conceptually straightforward, there are many fundamental questions about the role of culture conditions and cell physiology on the yield and quality of recombinant proteins produced in mammalian cell cultures. This lack of understanding is exacerbated by the short time period for cell line and process development in the biopharmaceutical industry, leaving little time for fundamental research in process science. Thus, despite the tremendous advances in the techniques available for biological characterization in the last decade, including genome sequencing, discovery-based technologies (e.g. microarrays, proteomics), and silencing RNA, and their application to Chinese Hamster Ovary (CHO) cells (the workhorse of the biotechnology industry), there are tremendous gaps in our understanding of industrially relevant cell lines.

With limited fundamental understanding of how process conditions affect production, the majority of process development is done empirically. Similarly, a lack of understanding of the ideal characteristics for an industrial cell line results in extensive, labor-intensive clone screening to pick the “best clone”. My laboratory has made significant advances in addressing a number of relevant questions such as the effects of on osmolarity recombinant protein production, identification of characteristics of highly productive cell lines, and understanding the role of protein sequence on expression levels. In addition, we have made a number of technological advances in related areas, including metabolic engineering of CHO cells to produce a bioengineered heparin and development of a novel cell-scaffold system for screening glaucoma therapeutics, which one of my former students, Dr. Karen Torrejon, turned into a successful company - Glauconix. In addition to my research program, I have a strong focus on curriculum and course development at the interface between engineering and the life sciences.

Why come to Ireland?

I am in Ireland, supported by a Fulbright Global Scholar Award, collaborating with faculty at the National Institute for Cellular Biotechnology (NICB) located at Dublin City University (DCU) to advance the science of bioproduction of therapeutic proteins. After spending fall in Ireland, the second half of my fellowship will be spending spring (their fall) at the University of Queensland in Brisbane, Australia. The objectives of this research are to improve production of therapeutic proteins by trying to engineer the cells to make proteins more efficiently; identifying characteristics of good producers so it is easier to pick a good productivity cell line out of a bunch of cells (kind of like looking for a needle in a haystack); determining why some therapeutic proteins are easier to make than others.

I selected these institutions for several reasons, the strength of their research programs, their relevance to my research interests (particularly in the areas of proteomics and bispecific antibodies), and for the unique collaboration opportunities they provide. In addition, both institutions have strong training programs and academic-industrial collaborations in biotechnology and mammalian cell bioprocessing. My reason for choosing to visit both these countries in one year is to observe and compare their training programs, with a goal of bringing expertise back to my home institution (SUNY Poly) to develop a training program in Nano-biomanufacturing.

A little more about NICB at DCU and Biotechnology in Ireland

As a result of significant government investment in life-science research and development, combined with a favorable tax policy, Ireland’s biotechnology industry has grown dramatically in the last decade. Nine of the world’s top 10 pharmaceutical companies have facilities in Ireland, with a total of 75 pharmaceutical companies operating in Ireland and 33 US FDA-approved pharmaceutical and biopharmaceutical plants, making Ireland the 7th largest exporter of medicinal and pharmaceutical products worldwide with ~ €39 billion in annual exports.

NICB is a leading research institute located on the DCU campus in Dublin, established in 2000. Building on the emphasis in Ireland on biotechnology and the biopharmaceutical industry, NICB’s mission is to provide targeted and applied solutions to challenges facing the biopharmaceutical industry and translational medicine, based on multi-disciplinary research and clinical and industrial collaboration. To support the growth of the biotechnology industry in Ireland and development of international best practices in biomanufacturing, the National Institute for Bioprocessing Research and Training (NIBRT) was established in 2010. NIBRT is a global center of excellence for training and research in bioprocessing with a new, world class facility in Dublin, replicating a modern bioprocessing plant with state of the art equipment. NIBRT is based on an innovative collaboration between multiple universities in Ireland, including DCU, with funding by the Government of Ireland through IDA Ireland.

Our collaborative research: NICB at DCU has an extensive research program in biopharmaceutical processing, particularly focusing on CHO cells. The recent sequencing of the CHO genome has permitted many novel studies of CHO cell physiology, particularly proteomic studies. For several years, my laboratory has been interested in how cell lines with high productivity differ from cell lines with low productivity. Through a long-standing collaboration with a biopharmaceutical company, we have a unique collection of CHO cell clones, producing the same recombinant monoclonal antibody with varying productivities. We have characterized a number of aspects of the cell physiology including gene copy number, mRNA levels, and protein expression. We observed that cell lines with higher gene copy number exhibited a disproportionate increase in protein expression. We hypothesize that there are changes in transcription factor expression and/or activity in the higher productivity clones. As many transcription factors are activated by phosphorylation, we propose to study these changes using phosphoproteomics, in which the phosphorylated proteins in the cell are identified and quantified to determine their levels of expression. Phosphoproteomic analysis is a challenging technique; however, Dr. Paula Meleady at DCU has extensive expertise in this area, particularly focusing on CHO cells.

Other activities

In addition to the collaborative research, I plan to develop and deliver a short course on the use of mammalian cells for production of non-protein therapeutics NICB, building on our unique research on producing a bioengineered heparin. I also intend to interact with the training facility at NIBRT to observe their facilities and training programs and participate in training activities. Finally, I intend to give guest lectures on my research outside of my host institutions to share my expertise and build collaborations. In Ireland, because of the small size of the country and widespread interest in biotechnology, I will visit several academic institutions and biopharmaceutical companies.

What I do besides work

I have been in Ireland for about a month and half with my entire family. My daughter is going to an all-girls secondary school in Raheny, and my son is taking classes at UCD. My husband is taking a 3 month break from his job at GE. Since being in Ireland, we have taken advantage of the saying that “in Europe, 100 miles is a long distance and in the US, 100 years is a long time” and seen many interesting historical (both ancient and modern) sites. My daughter and I visited the monastery at Glendalough; we went to Malahide Castle; my husband and son went to the General Post Office, and we have lots more to do before we leave. We also had the opportunity to go to the pub and watch the men’s Gaelic football championship (congrats to Dublin), which I am told may be the best (and only) example of Gaelic football I have ever seen. My son celebrated his 18th birthday with his first legal pint and is looking forward to a visit to the Jameson distillery, and my daughter was introduced to “Taytos” and Chippies (though I think since she does not eat fish, putting chips in a sandwich is a little strange). And we are getting used to the idea that every day you need your raincoat and if you are lucky, your sunglasses as well. Like many folks in Ireland, we are going to spend the midterm break in Spain to get a little more sun.

A little more about Fulbright

Supporting the late Senator J. William Fulbright’s goal of developing international understanding through open communication and cooperative partnerships, the Fulbright program provides bilateral exchange opportunities between the US and 140 countries worldwide. Distinguished participants in the program have become heads of state, judges, ambassadors, cabinet ministers, CEOs, and university presidents, as well as leading journalists, artists, scientists, and teachers. They include 58 Nobel Laureates, 82 Pulitzer Prize winners, 31 MacArthur Fellows, 16 Presidential Medal of Freedom recipients, and thousands of leaders across the private, public, and non-profit sectors. Since its inception in 1946, more than 370,000 “Fulbrighters” have participated in the Program. I am delighted to join their ranks.


1 Response

  1. Susan, you are an AMAZING Nanobioscientist!!!! What an incredible opportunity for you to work in such prestigious places and help to create medical advances that will extend and improve people’s lives! Thank you!!! All the best to you and the family! Sue Ann Grosberg
  2. […] NICB Blog: Optimizing Recombinant Protein Production in Cultured Mammalian Cells […]

Leave your comments