Research Focus

Research foci of our laboratory include biology of the selected diseases (e.g., diabetes, cancer and immune diseases) and research and development (R&D) of nutraceuticals and therapeutics for the above diseases. We highlight the key findings and research directions below.

1. Biology and study of the selected diseases

1-1. Diabetes
Loss of β-cell number and function is a hallmark of diabetes. β-cell preservation is emerging as a promising strategy to treat and reverse diabetes as described in Fig. 1. Our lab has identified a novel gene (WCY1). We found that WCY1 is a key player in β-cell pathogenesis and diabetes development. WCY1 was found to be primarily expressed in pancreatic islets and β-cells. This expression was up-regulated in β-cells and blood of mice in response to excess nutrients. Ablation of WCY1 alleviated diabetes as shown by reduced islet destruction, blood glucose and HbA1C, reactive oxygen species (ROS), and increased insulin secretion in diabetic mouse models. Strikingly, this ablation normalized 58% of diabetic mice and alleviated 42% of mice. Conversely, overexpression of WCY1 had the opposite clinical outcomes in the mice. In addition, WCY1 positively regulated β-cell death and dysfunction and ROS production. These findings characterize WCY1 as a crucial regulator of β-cell pathogenesis and diabetes, suggesting WCY1 may be a novel therapeutic and diagnostic target of diabetes.

1-2. Cancer
Cancer is a leading cause of death worldwide, accounting for 8.2 million deaths each year. As a result of genetic alterations, cancer cells accumulate defects in regulatory circuits that govern normal cell proliferation and homeostasis. Cancer cells may acquire the capability to sustain proliferation, resist cell death, evade growth suppression, enable replicative immortality, induce angiogenesis, and activate invasion/metastasis. Apoptotic pathways are frequently dysfunctional in cancer cells, and breaking the resistance of tumors to death is one of the major anti-cancer approaches. The identification of novel therapeutic targets that are specific to tumors and do not affect normal tissues may promote the development of new anti-tumor strategies for clinical application.

PDI, a protein disulfide isomerase, is implicated in the growth and death of tumor cells; however, its molecular basis and therapeutic potential in cancer are unclear. Here, we found that PDI expression was upregulated in a variety of tumor cell lines and human lung adenocarcinoma tissues. Knockdown and overexpression of Pdia4 in tumor cells showed that Pdia4 facilitated cell growth via the reduction of caspases 3 and 7 activity. Consistently, Lewis lung carcinoma (LLC) cells overexpressing Pdia4 grew faster than did parental cells in tumor-bearing mice, as shown by a reduced survival rate, increased tumor size and metastasis, and decreased cell death and caspases 3 and 7 activity. Pdia4 knockdown resulted in opposite outcomes. Moreover, results obtained in mice with spontaneous hepatoma indicated that Pdia4 deficiency significantly reduced hepatic tumorigenesis and cyst formation and increased mouse survival, tumor death, and caspases 3 and 7 activity. Mechanistic studies illustrated that Pdia4 negatively regulated tumor cell death by inhibiting procaspases 3 and 7 degradation via their mutual interaction. Finally, we found that PDI inhibitors reduced tumor development via enhancement of caspase-mediated cell death in TSA tumor-bearing mice. These findings characterize the contribution of Pdia4 to tumorigenesis and suggest Pdia4 as a potential therapeutic target for cancer (Fig. 2).

1-3. Immune diseases
Immune system is to defend host from pathogens. Immune cells are key players of host defense. However, dys-regulation of immune cells is associated with immune disorders. Thus, understanding of immune cell biology is pivotal to academic advances of immunology and prevention and treatment of immune disorders. Over the past years, we have concentrated on signaling pathway of T cells. More recently, we studied the myeloid-derived suppressor cells (MDSC) in the induction of immune tolerance and prevention of autoimmune diabetes in mouse models. Currently, we are developing the therapeutics for autoimmune diseases such as autoimmune diabetes (i.e., type 1 diabetes) as delineated in Fig. 3.

2. R&D of nutraceuticals and therapeutics for the selected diseases

2-1. Botanical formulation and lead compounds for diabetes
 

Our previous publications showed that Bidens pilosa (BP) extracts could lower blood glucose in db/db mice, a mouse model of type 2 diabetes (T2D). The mechanism of their extracts was implicated in increased insulin production and protected islet architecture in db/db mice. Based on the activity-directed fractionation and isolation strategy, we identified three polyynes as bioactive compounds from the B. pilosa extracts. Among the identification of active compounds from this plant, we also explored the efficacy and mechanism of the most potent compound, cytopiloyne, on T2D in db/db mice. A similar outcome was observed in mouse model. Similar preclinical outcomes were observed in mouse model. Next, we studied the anti-diabetic mechanism of action of cytopiloyne. We showed that cytopiloyne failed to decrease blood glucose in streptozocin (STZ)-treated mice whose n ncells were already destroyed. Additionally, cytopiloyne dose-dependently increased insulin secretion and expression in n cells. The overall data demonstrate that BP and cytopiloyne treats T2D via regulation of insulin production involving the regulation of cells. Besides, we also completed the good agriculture practice (GAP) study in this plant. Currently, we plan to complete toxicology study under good laboratory practice (GLP) in cooperation with licensee. The final goal is to develop the botanical drug into clinical trial in cooperation with the licensee.

2-2. Lead compounds for cancer and/or immune diseases
Using virtual screening and bioassays, we started to screen 261 plant compounds using molecular docking based on the homology model of PDI, followed by PDI bioassays. The best two hits (compounds 1 and 2), were identified. The docking positions of the best hits, 2, are shown in Fig. 4. In cooperation with medicinal chemists, we screened a library of the derivatives modified from compound 2. After several rounds of lead optimization, hopefully, drug candidates with an IC50 value within the nanomolar range will be expected.

3. R&D of phytogenics for animal health
The global market value of livestock and poultry is valued 1.4 trillion US dollars annually. Due to the global trend of banning the preventive use of antibiotics, antibiotic-free farming is now emerging as an alternative to maintain animal health. In the interest of food safety and public health, edible plants and their compounds are now re-emerging as an alternative veterinary medicine for meat-producing animals. Over the past 5 years, we have succeeded in commercializing one phytogenic formulation, also known as coccimort (CM), for chicken coccidosis locally and internationally (Fig. 5). First, we found that CM was therapeutically effective against coccidiosis in chickens as evidenced by a survival rate, gut pathology, fecal oocyst excretion and anti-coccidial index. Next, we showed that CM significantly increased body weight gain and decreased feed conversion ratio in chickens. Besides, drug resistance of E. tenella to CM and salinomycin, a commercial anti-coccidial drug, was assessed in 169 chickens using the anti-coccidial index. Unexpectedly, this index showed that unlike salinomycin, CM induced little, if any, drug resistance to Eimeria in chickens. Finally, pyrosequencing data on gut bacteria in chickens indicated that CM affected the composition of gut bacteria by reduction of harmful bacteria and increase of probiotics. This change in bacteria composition was correlated with body weight gain, feed conversion ratio and gut pathology in chickens. Overall, this work suggests CM as a novel, natural remedy remedy for avian coccidiosis via multiple mechanisms, including prebiotic action and interference with protozoan life cycle. Excitingly, Taiwanese Council of Agriculture (COA) approved the use of CM as feed additive in Taiwan in 2014. The application of the CM for investigational animal drug (INAD) will be filed to Taiwanese COA in the near future.