In fact, the findings in this study were inspired from preclinical testing of two Bcl6-targeting agents that Dr. Melnick and his Weill Cornell colleagues have developed to treat DLBCLs. These experimental drugs are RI-BPI, a peptide mimic, and the small molecule agent 79-6.
Dr. Melnick says the discovery that a master regulatory transcription factor can be targeted offers implications beyond just treating DLBCL. Recent studies from Dr. Melnick and others have revealed that Bcl6 plays a key role in the most aggressive forms of acute leukemia, as well as certain solid tumors.
Transcription factors are responsible for either inhibiting or promoting the expression of genes, and master regulatory transcription factors are the equivalent of the CPU of a computer their actions regulate thousands of genes in different kinds of cells. For example, Bcl6 can control the type of immune cell that develops in the bone marrow -- playing many roles in the development of B cells, T cells, macrophages and other cells -- including a primary and essential role in enabling B-cells to generate specific antibodies against pathogens.
"When cells lose control of Bcl6, lymphomas develop in the immune system. Lymphomas are 'addicted' to Bcl6, and therefore Bcl6 inhibitors powerfully and quickly destroy lymphoma cells," Dr. Melnick says.
The big surprise in the current study is that rather than functioning as a single molecular machine, Bcl6 instead seems to function more like a Swiss Army knife, using different tools to control different cell types. This multi-function paradigm could represent a general model for the functioning of other master regulatory transcription factors.
"In this analogy, the Swiss Army knife, or transcription factor, keeps most of its tools folded, opening on
|Contact: Lauren Woods|
Weill Cornell Medical College