Modeling Cancer, One Organoid at a Time

Shania Sarango

My childhood friend, Emilly, passed away from chordoma, a rare bone cancer, last year. With a heavy heart, I knew I wanted my senior research project to be cancer-related. I looked through the Stevens undergraduate research website to choose an advisor in the Chemistry and Chemical Biology Department whose research aligned with my interests. Interestingly, I came across Professor Hongjun Wang’s research on multifunctional tissue/organ formation and nanomedicine in cancer. He’s a professor in the Biomedical Engineering Department, a field of study that was unfamiliar territory to me. However, his laboratory, the Semcer Center for Healthcare Innovation, provided unique gateways into advanced cancer research. After many meetings with him, I now conduct research focused on the creation and characterization of organoid structures of colon cancer, or colon tumor organoids. 

Current cancer research requires accurate models to understand tumor growth and investigate treatment efficacy for specific cancer types. Animal models have been used in cancer research for over a century, however, they fail to predict human-specific responses and raise significant ethical issues. There are also two-dimensional cell cultures which, unfortunately, are unable to replicate the complexities of tumors. Recently, three-dimensional cell cultures known as tumor organoids have been used as models in advanced cancer research, including my own. 

Before I move onto the complexities of tumor organoids, let me explain what organoids are first. Organoids are essentially simplified versions of organs or tissues, thus making them three-dimensional cell cultures that are able to mimic the architecture and function of organs or tissues. These structures can be grown from stem cells or tissue-specific cells, meaning organoids can be derived from brain, liver, intestine, kidney, lung, prostate, stomach, thyroid, pancreas, vascular, endometrium, and retinal cells, so long as they are supplemented with niche factors specific to each organoid type. Below is an image of an organoid derived from brain cells by scientists in the Harvard Stem Cell Institute. 

Figure 1. A section of a brain organoid after three months of culture. The different colors mark distinct types of cells, highlighting the organoid's structural complexity.

Tumor organoids are organoids developed from cancer cells, giving these structures the ability to replicate tumor-specific properties. Therefore, they are used to study tumor metastasis and responses to certain therapeutic agents. There are many ways to develop tumor organoids, the two most common being patient-derived and cell-line derived tumor organoids. In patient-derived tumor organoids, tumor tissue is collected from a patient to create their unique tumor organoid. For example, a review of studies that have developed patient-derived colon cancer organoids explains that researchers obtain colon cancer tissue via biopsy or surgery. The tissue is then finely minced into small tissue cubes approximately one millimeter cubed in size using scalpels. The 1 mm3 minced tissue then undergoes mechanical or enzymatic digestion to dissociate into single cells. These single cells are then mixed with basal membrane extract, a biological material commonly used in three-dimensional cell cultures, such as organoid formation. The use of basal membrane extract is particularly important because it is rich in extracellular matrix (ECM) proteins, thus allowing basal membrane extract to mimic the structural environment of the ECM. The ECM is needed in order for cells to grow and attach to one another. Therefore, the cell-basal membrane extract suspension is plated in domes and then overlaid with tissue-specific medium, ultimately organizing into patient-derived colon cancer organoids. Procedures vary among studies, however, this methodology is commonly used to investigate colon cancer organoid models made from patient cells. 

Figure 2. A simplified overview of patient-derived tumor organoid generation found in review titled "Advancements in Research and Treatment Applications of Patient-Derived Tumor Organoids in Colorectal Cancer" 

My research involves the creation of cell-line derived organoids. Specifically, my lab provides me with the SW480 cell line, derived from human colon adenocarcinoma or the primary tumor of colorectal cancer. You may be wondering what my research is investigating if patient-derived tumor organoids of colon cancer have already been developed and are currently being used to analyze responses to treatment. While current studies have established a methodology for the creation of colon cancer organoids, it results in unstable and non-uniform tumor organoids. Stability and uniformity are extremely important in tumor organoid creation because it enables reproducibility, since the organoids would be able to maintain their structure and composition over time. This in turn allows for longer culture periods, where researchers can study tumor progression and drug responses in a more controlled manner. When testing certain drugs on tumor organoids, it is crucial that they are similar in size and shape to get accurate and consistent results in regard to drug testing. If tumor organoids are vastly different, it can make the measurements obtained unreliable. Therefore, my research investigates whether the use of microspheres results in more stable and uniform tumor organoid formation. 

Microspheres are tiny spherical particles made of polymers. I want to test whether microspheres can mimic the ECM similar to how the basal membrane extract does in other studies. The use of basal membrane extract is what results in non-uniform and unstable tumor organoids since it provides limited structural support. The microspheres I make in my experiment are polycaprolactone (PCL) microspheres. PCL is a biodegradable and biocompatible polymer. PCL microspheres will act as scaffolding that mimics the ECM and thus enable the creation of uniform organoid-like structures. An important characteristic of these microspheres is that they must be porous, or contain pores, in order to effectively mimic the ECM and culture the colon cancer cells from the SW480 cell line onto them. To create these pores, I use an ammonium bicarbonate solution that when mixed with PCL and heated, decomposes into carbon dioxide, ammonia, and water, forming bubbles within the polymer matrix that leaves behind pores. I am finalizing the fabrication of these porous PCL microspheres and will be moving on to cell culturing shortly. Next semester, I will characterize the cell-laden microspheres for their organoid-like structure. 

Figure 3. Porous PCL microspheres that I fabricated and observed under a compound light microscope. Diameters in this trial ranged from 200-230 micrometers.

Organoids are a fairly new development in cancer research, but they have the potential for many applications, not limited to cancer modeling. As mentioned previously, tumor organoids can be used for drug screening, precision medicine, and most importantly, personalized medicine. Current therapies, such as chemotherapy, result in adverse side effects since this form of treatment affects healthy and cancerous cells alike. Using tumor organoids as models for cancer, researchers can test and establish more targeted approaches that treat tumors directly, which ultimately minimizes adverse side effects. With personalized medicine, researchers can develop patient-derived tumor organoids to determine what treatment regimens work best for individual patients, resulting in better decision-making and improved patient outcomes. 

Although this field of cancer research reduces concerns associated with performing clinical trials on humans and animals, there are ethical concerns with the use of cell lines in medical research. Humans whose cells are used for cell lines are not compensated because they technically have no legal ownership of their affected cells. This was the case for Henrietta Lacks, an African American woman whose cervical cancer cells were used to create the HeLa cell line, the first immortalized human cell line. According to the “Legacy of Henrietta Lacks” by Johns Hopkins Medicine, a sample of her cancer cells was sent to Dr. George Gey, a cancer researcher, who had been collecting cells from all cervical cancer patients. Each sample quickly died except for Mrs. Lacks' whose cells kept growing and doubled every 20 to 24 hours. This made the HeLa cell line one of the most important in cancer research. However, she did not consent for her cells to be derived into a cell line. Now, informed consent is required if researchers wish to use a patient’s cells for medical research.

What makes tumor organoid research unique is that eventually, it will progress from the use of cell lines into the complete use of patient cells for the creation of patient-derived tumor organoids. This, of course, requires the consent of the patient but will mitigate ethical concerns because the organoids are directly representative of the patient’s own tumor. In the end, this approach will benefit patients, as treatments can be tested on their organoids, enabling more personalized and effective therapies. As my research advisor, Dr. Wang said, “Organoids are the future of understanding cancer at a patient-specific level. But to do this, we have to begin with the creation of organoids using established cell lines.”

There is great promise in the use of organoids as models for cancer, and I am excited to see how my research unfolds next semester. Through this research journey, I have gained a renewed commitment to making a difference in the fight against this awful disease. As I continue my research project, I carry Emilly’s memory with me, hopeful that my work, no matter how small, can contribute to a future where fewer families and friends have to experience such loss. 

Resources:

Fontana, F., Marzagalli, M., Sommariva, M., Gagliano, N., & Limonta, P. (2021, June 13). In vitro 3D cultures to model the tumor microenvironment. Cancers. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8231786/ 

Organoid culture. MedChemExpress. (n.d.). https://www.medchemexpress.com/organoid-culture.html 

Organoids: A new window into disease, development and Discovery. Harvard Stem Cell Institute (HSCI). (2017, November 7). https://hsci.harvard.edu/organoids 

Tuveson, D., & Clevers, H. (n.d.). Cancer modeling meets human organoid technology. https://www.science.org/doi/10.1126/science.aaw6985 

van der Graaff, D., Seghers, S., Vanclooster, P., Deben, C., Vandamme, T., & Prenen, H. (2024, July 26). Advancements in research and treatment applications of patient-derived tumor organoids in colorectal cancer. MDPI. https://www.mdpi.com/2072-6694/16/15/2671 

Multiple applications of organoids. CUSABIO. (n.d.). https://www.cusabio.com/Organoids/Multiple-Applications-of-Organoids.html 

The Legacy of Henrietta Lacks. Johns Hopkins Medicine. (n.d.). https://www.hopkinsmedicine.org/henrietta-lacks