Structure-based modeling combined with rational
drug design, and high throughput screening approaches offer significant potential for identifying and developing lead compounds with therapeutic potential. The present review focuses on these two approaches using explicit examples based on specific derivatives of
Gossypol generated through rational design and applications of a
cancer-specificpromoter derived from Progression Elevated Gene-3. The
Gossypol derivative
Sabutoclax (BI-97C1) displays potent anti-
tumor activity against a diverse spectrum of human
tumors. The model of the docked structure of
Gossypol bound to Bcl-XL provided a virtual structure-activity-relationship where appropriate modifications were predicted on a rational basis. These structure-based studies led to the isolation of
Sabutoclax, an optically pure isomer of
Apogossypol displaying superior efficacy and reduced toxicity. These studies illustrate the power of combining structure-based modeling with rational design to predict appropriate derivatives of lead compounds to be empirically tested and evaluated for bioactivity. Another approach to
cancer drug discovery utilizes a
cancer-specific promoter as readouts of the transformed state. The promoter region of Progression Elevated Gene-3 is such a promoter with
cancer-specific activity. The specificity of this promoter has been exploited as a means of constructing
cancer terminator viruses that selectively kill
cancer cells and as a systemic imaging modality that specifically visualizes in vivo
cancer growth with no background from normal tissues. Screening of small molecule inhibitors that suppress the Progression Elevated Gene-3-promoter may provide relevant lead compounds for
cancer therapy that can be combined with further structure-based approaches leading to the development of novel compounds for
cancer therapy.