The quinoxaline di-N-oxide DCQ blocks breast cancer metastasis in vitro and in vivo by targeting the hypoxia inducible factor-1 pathway.

Background: Although tumor hypoxia poses challenges against conventional cancer treatments, it provides a therapeutic target for hypoxia-activated drugs. Here, we studied the effect of the hypoxia-activated synthetic quinoxaline di-N-oxide DCQ against breast cancer metastasis and identified the underlying mechanisms.

Methods: The human breast cancer cell lines MCF-7 (p53 wildtype) and MDA-MB-231 (p53 mutant) were treated with DCQ under normoxia or hypoxia.

Targeting hypoxia for sensitization of tumors to radio- and chemotherapy.

The heterogeneous distribution of hypoxic regions within solid tumors renders them refractive to chemo- and radio-therapies and contributes positively to tumor invasion and metastasis. Moreover, hypoxia favors the enrichment of cancer stem cells by interacting with differentiation signals via the maintenance of stem cell properties of undifferentiated cells or via the induction of cellular dedifferentiation. The discovery of the hypoxia inducible factor 1alpha (HIF-1α) has led to the current extensive interest in the signal molecules related to tumor hypoxia and the major regulatory pathways that control the family of hypoxia-inducible factors as potential molecular targets for cancer therapeutics.

Thymoquinone induces apoptosis in malignant T-cells via generation of ROS.

We show that HTLV-1 negative leukemia cells are more sensitive to TQ due to higher levels of drug-induced reactive oxygen species (ROS). PreG1 population in HTLV-1 negative Jurkat and CEM was higher than HTLV-1 transformed HuT-102 and MT-2 cells. Peripheral blood mononuclear cells were more resistant.

Unusual Friedlander reactions: a route to novel quinoxaline-based heterocycles.

Acid catalyzed Friedlander reactions of a number of 2,3-dihydro-1H-cyclopenta[b]quinoxaline-1-ones with 2-aminobenzaldehyde yield, unexpectedly, 8H-indolo[3,2-a]phenazine and quinolino[2,3-c]cyclopentadienone[2,3-b]quinoxalines, the structures of derivatives of which were confirmed by X-ray crystallography. Easy routes to novel quinoxaline-based indoles, quinolones, and quinoxaline-1,4-dioxides are reported, and proposed mechanisms for the unexpected products are discussed.