Fei Liu, PhD

Education and Training

• Medical University of China, MD
• Military Medical University, PhD, 2002

Research Interests

• Roles of mesenchymal stem cells (MSCs) in growth and metastasis of cancer and application of MSCs for cancer treatment MSCs are an essential source of cancer-associated fibroblasts (CAFs) that promote growth and metastasis of cancers. On the other hand, the tumor-tropic property makes MSCs a promising vehicle for gene-therapy of cancers. Liu's recent work indicated that Transforming growth factor (TGF-?) pathway is essential for differentiation of MSCs into CAFs and the interaction between MSCs and cancer cells, which suggested that blocking TGF-? pathway would significantly improve the safety of MSCs-mediated therapies in cancer patients. Meanwhile, blocking TGF-? pathway in MSCs also disrupted the cytokine network essential for maintenance of breast cancer stem cells. Liu's current works are on MSC mediated disruption of niches for breast cancer stem cells and metastasis. Molecular cues for regeneration of salivary glands. Salivary gland destruction is a major consequence of various pathological conditions such as radiation therapy for head and neck cancer and Sjögren's syndrome. Dry mouth syndrome severely compromises quality of life in these patients, while currently available treatments cannot restore salivary gland functions. Stem cells based regenerative therapy is a promising direction to treat this condition. Liu's work revealed for the first time that Wnt (wingless/int) and Hedgehog signaling promote expansion of salivary gland stem cells. Transient activation of Wnt signaling prevented radiation-induced hypo-salivation by prevention of apoptosis but can't rescue it. Transient activation of Hedgehog pathway rescued radiation-induced hypo-salivation by perseveration of functional salivary stem/progenitor cells and innervation. The molecular mechanisms of Hedgehog-mediated rescue effects are under investigation. Molecular cues for development and regeneration of tooth root/periodontal tissues. From the clinical point of view, root/periodontal tissues (R/PT) are the most important part of teeth, which provide support and fixture for natural or artificial crowns and are not replaceable with current technologies. It's believed that like the development of tooth crown, the formation of R/PT also requires sequential and reciprocal interaction between dental epithelia and mesenchyme mediated by protein messengers known as signaling molecules. Liu's recent work revealed that interaction between Bone Morphogenetic Protein (BMP) and Wnt pathways determine the fate of dental epithelia both collaboratively and antagonistically. This project will provide essential data for understanding the complex molecular control of this process, and clues for designing new strategies to build up a bio-root/periodontal complex in cases of tooth loss due to disease or trauma. Graduate training is available through the Medical Science PhD program (College of Medicine), through the MD/PhD program(College of Medicine) and other programs that our faculty are affiliated with joint research.