Project title: Development of in vitro and in vivo preclinical models for small bowel NET

Po Hien Ear, PhD University of Iowa

Po Hien Ear, PhD

What question will scientists try to answer?

Can we develop laboratory models of neuroendocrine tumors (NETs) to use in large-scale drug screens that may identify the rare anti-tumor agents that can effectively treat human NETs, in particular, the deadly NETs that often metastasize?

Why is this important?

It is critical to develop laboratory models of NETs in order to test the large numbers of compounds needed to find the few possessing good anti-tumor activity. Regrettably, non-human models of cancer often fail to fully recapitulate the human disease and many anti-cancer drugs that were effective in the laboratory failed to work as well in human patients. Thus, it may be more effective if cancer therapeutics were screened using human cell NET models. Unfortunately, there are very few reliable patient-derived NET cell lines that researchers can use to test drugs, so Dr. Ear has developed a novel strategy to circumvent the lack of these cell lines for her large-scale drug screens.

What will scientists do?

Dr. Ear has developed a way to isolate small-bowel NET cells directly from resected patient tumors and grow them in the laboratory as small clusters of cells called “spheroids.” She can grow these clusters in large enough numbers to be used to screen the anti-tumor properties of hundreds of potential therapeutic compounds.

Furthermore, she also proposes to inject these spheroids directly into the spleen of a strain of mice that will allow human tumor cells to survive and metastasize to the liver, as it often does in human patients. Because these NET spheroids are human cells, she can use the same NET-imaging agent used in humans (Ga-68 dototoc) in order to track and analyze their metastasis by PET scan in the living animals. She can then further test the effectiveness of anti-tumor drugs identified in her initial studies using this live metastasis animal model.

How might this improve treatment of NETs?

Dr. Ear’s work has the potential to move us closer to establishing a reliable laboratory disease model that researchers can use to study the process of NET metastasis and to test, and identify, new and different drugs for therapeutic development.

What is the next step?

If successful, she will publish her results and make her cell or mouse models available to the scientific community to further our understanding of NET biology, NET metastasis and to uncover future therapeutic options for the treatment of NET patients.


Neuroendocrine tumors (NETs) and neuroendocrine carcinomas (NECs) can occur throughout the body and are named for their resemblance to neuronal cells and the fact that they secrete hormones. Patients with NET and NEC metastases are rarely cured despite surgical and medical management. Several drugs have been approved for treating NETs, but only a small percentage of tumors actually respond to the treatment. There is an urgent need to identify new drugs targeting NET metastases. However, research into new treatment options for these tumors have been hindered by the limited number of cell and mouse models available for drug testing.

The purpose of this study was to use patient-derived NET samples for i) performing drug screens and ii) to develop mouse models of NET and NECs. In brief, we established a method to culture 20 NET and NEC samples as 3-dimensional spheroids, performed a systematic drug screen, and showed that the 2 top drugs can prevent tumor growth in mice. In addition, we developed 2 patient-derived xenograft models for testing the somatostatin receptor imaging agent.

Additional Details

  • City: Iowa City
  • State: Iowa
  • Grant Duration: 2 years
  • Grant Partner: North American Tumor Society (NANETS)
  • Awards: Basic/Translational Science Investigator (BTSI)


NETRF funds laboratory research to understand the development of neuroendocrine tumors and translational research to explore new concepts in treatment. Research grant descriptions and research updates from NETRF are not intended to serve as medical advice. It can take years for research discoveries to be fully validated and approved for patient care. Always consult your health care providers about your treatment options.

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