Research Focus

Nature has been a rich source for drug discovery for centuries. Many anticancer drugs were developed from plant metabolites. However, microorganisms from plants, oceans and insects etc. are underexplored natural sources for anticancer drug discovery. (i) It is well known that bacteria are producers of variety of bioactive compounds. But it is fair to say that no single strain has been entirely studied for its secondary metabolites; and not much attention has been paid to some bacteria (for example, deep-sea bacteria, bacteria associated with arthropods, and bacteria from lower animals etc.) that are therefore, underexplored for their bioactive compounds. (ii) Each of the about 250,000 land plant species hosts one or more endophytes. An endophyte could be either a bacterium or a fungus. Endophytic fungi have been studied, but few of these endophytes have been characterized, and they are very underexplored for their secondary metabolites when compared to fungal plant pathogens and fungal soil isolates. (iii) Oceans cover nearly 70% of the earth's surface and possess nearly 300,000 described species of plants and animals from marine sources, comprising about half of the total biodiversity. However, the development of marine natural products as therapeutic agents is still in its early stages due to the lack of an analogous ethno-medical history as compared to terrestrial habitats, together with the relative technical difficulties in collecting the marine floral samples. On the other hand, microorganisms can grow in almost all marine habitats, for example, coral, algae, sponges, fishes and sediments etc., but they are underexplored. Hence, microorganisms in the marine environment are also an extremely rich source for anticancer drug discovery.

The Cao laboratory focuses on exploring bacteria, endophytic fungi and marine-associated microorganisms for anticancer drug discovery. This will be carried out through collaboration between different disciplines at the UH Cancer Center with novel approaches to guide the identification of strains that have the potential to produce anticancer drug leads; novel dereplication technique (e.g., LC/MS etc.) to identify strains that produce novel compounds; structure elucidation of active compounds by NMR, chemical modifications and degradations, and x-ray analysis; high throughput screening through collaboration with oncologists; and genome sequencing if necessary.

The Cao Lab also works on herbal medicines used for diseases related to cancer and diabetes, etc., and small molecules with various biological functions in bacteria and the human body.