CXCR4 plays a crucial role in the inflammatory disease process, providing an attractive means for drug targeting. A series of novel amide-sulfamide derivatives were designed, synthesized and comprehensively evaluated. This new scaffold exhibited much more potent CXCR4 inhibitory activity, with more than 70% of the compounds showed notably better binding affinity than the reference drug AMD3100 in the binding assay. Additionally, in the Matrigel invasion assay, most of our compounds significantly blocked the tumor cell invasion, demonstrating superior efficacy compared to AMD3100. Furthermore, compound IIj blocked mice ear inflammation by 75% and attenuated ear edema and damage substantially in an in vivo model of inflammation. Western blot analyses revealed that CXCR4 modulator IIj significantly blocked CXCR4/CXCL12-mediated phosphorylation of Akt. Moreover, compound IIj had no observable cytotoxicity and displayed a favourable plasma stability in our preliminary pharmacokinetic study. The preliminary structure-activity relationships were also summarized. In short, this novel amide-sulfamide scaffold exhibited potent CXCR4 inhibitory activity both in vitro and in vivo. These results also confirmed that developing modulators targeting CXCR4 provides an exciting avenue for treatment of inflammation.
The CXC chemokine receptor 4 (CXCR4) is involved in chemotaxis and serves as a coreceptor for T-tropic HIV-1 viral entry, thus making this receptor an attractive drug target. Recently, crystal structures of CXCR4 were reported as complexes with the small molecule IT1t and the CVX15 peptide. Follow-up efforts to model different antagonists into the small molecule CXCR4:IT1t crystal structure did not generate poses consistent with either the X-ray crystal structure or site-directed mutagenesis (SDM). Here, we compare the binding pockets of the two CXCR4 crystal structures, revealing differences in helices IV, V, VI, and VII, with major differences for the His203 residue buried in the binding pocket. The small molecule antagonist AMD11070 was docked into both CXCR4 crystal structures. An AMD11070 pose identified from the CXCR4:CVX15 model presented interactions with Asp171, Glu288, Trp94, and Asp97, consistent with published SDM data, thus suggesting it is the bioactive pose. A CXCR4 receptor model was optimized around this pose of AMD11070, and the resulting model correlated HIV-1 inhibition with MM-GBSA docking scores for a congeneric AMD11070-like series. Subsequent NAMFIS NMR results successfully linked the proposed binding pose to an independent experimental structure. These results strongly suggest that not all small molecules will bind to CXCR4 in a similar manner as IT1t. Instead, the CXCR4:CVX15 crystal structure may provide a binding locus for small organic molecules that is more suitable than the secondary IT1t site. This work is expected to provide modeling insights useful for future CXCR4 antagonist and X4-tropic HIV-1 based drug design efforts.
Many forms of solid tumor have a characteristic feature known as hypoxia, which describes a low or non-existent presence of oxygen in the cellular microenvironment. This decrease in oxygen causes activation of the hypoxia inducible factor (HIF) pathway, which activates the transcription of many genes that cause cell proliferation, metastasis, increased glycolysis and angiogenesis. Increased HIF expression has been linked with poor patient prognosis, increased malignancy, and therapeutic resistance. Previous work in our lab has identified 1 and 2 as inhibitors of the HIF pathway, specifically as disrupters of the p300-HIF-1α complex formation. A library of sulfonamide analogs has been designed and synthesized with the intent of examining the SAR of this series of compounds and improving potency and physicochemical properties as compared with lead compounds 1 and 2. At the end, we have achieved a thorough understanding of the structural features critical for future optimization work.
We have discovered that 3,4-dimethoxy-N-[(2,2-dimethyl-2H-chromen-6-yl) methyl]-N-phenylbenzenesulfonamide, a novel small molecule HIF-1 pathway inhibitor, can antagonize tumor growth in animal models of cancer, but the treatment necessitates its delivery in a formulation, due to poor water solubility (<15 μg/mL; pH 7.4), evidencing that the chemotype needs further exploration of its amenability to additional chemical modifications for ultimate optimization of function and pharmacology.
As a first step towards this goal we investigated the structure-activity relationships of 15 lipophilic 2,2-dimethyl-2H-chromene based arylsulfonamide analogs of 3,4-dimethoxy-N-[(2,2- dimethyl-2H-chromen-6-yl)methyl]-N-phenylbenzenesulfonamide to find out strategies of modification. A 3,4-dimethoxybenzenesulfonyl group in region 1 showed the strongest inhibition among five arylsulfonyl groups tested. The presence of propan-2-amine in region 2 conferred the strongest inhibitory effect of the compound on HIF-1 activated transcription in a reporter assay. These findings are important as they help define the structural motifs where the 3,4-dimethoxy-N-[(2,2-dimethyl-2H-chromen-6-yl)methyl]-N- phenylbenzenesulfonamide can be chemically modified to improve its pharmacological properties towards development as a cancer therapeutic.