Combinatorial biosynthesis of antitumor indolocarbazole compounds

^†Departamento de Biología Funcional e Instituto Universitario de Oncología del Principado de Asturias, Universidad de Oviedo, 33006 Oviedo, Spain; and ^‡Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, Lexington, KY 40536-0082

Edited by Arnold L. Demain, Drew University, Madison, NJ (received for review October 25, 2004)

Abstract

Rebeccamycin and staurosporine are natural products with antitumor properties, which belong to the family of indolocarbazole alkaloids. An intense effort currently exists for the generation of indolocarbazole derivatives for the treatment of several diseases, including cancer and neurodegenerative disorders. Here, we report a biological process based on combinatorial biosynthesis for the production of indolocarbazole compounds (or their precursors) in engineered microorganisms as a complementary approach to chemical synthesis. We have dissected and reconstituted the entire biosynthetic pathway for rebeccamycin in a convenient actinomycete host, Streptomyces albus. This task was achieved by coexpressing different combinations of genes isolated from the rebeccamycin-producing microorganism. Also, a gene (staC) was identified in staurosporine-producing microbes and was shown to have a key role to differentiate the biosynthetic pathways for the two indolocarbazoles. Last, incorporation of the pyrH and thal genes, encoding halogenases from different microorganisms, resulted in production of derivatives with chlorine atoms at novel positions. We produced >30 different compounds by using the recombinant strains generated in this work.

cancer

Footnotes

↵ § To whom correspondence should be addressed. E-mail: jrohr2{at}uky.edu (for chemical communications) and jasalas{at}uniovi.es (for molecular biology communications).
Author contributions: C.S., C.M., and J.A.S. designed research; C.S., L.Z., A.F.B., and A.P.S. performed research; C.S., L.Z., A.F.B., and J.R. analyzed data; and C.S. and J.A.S. wrote the paper.
This paper was submitted directly (Track II) to the PNAS office.