Quinazoline-chalcone hybrids as HDAC/EGFR dual inhibitors: Design, synthesis, mechanistic, and in-silico studies of potential anticancer activity against multiple myeloma

Two new series of quinazoline-chalcone hybrids were designed, synthesized as histone deacetylase (HDAC)/epidermal growth factor receptor (EGFR) dual inhibitors, and screened in vitro against the NCI 60 human cancer cell line panel. The most potent derivative, compound 5e bearing a 3,4,5-trimethoxyphenyl chalcone moiety, showed the most effective growth inhibition value against the panel of NCI 60 human cancer cell lines. Thus, it was selected for further investigation for NCI 5 log doses. Interestingly, this trimethoxy-substituted analog inhibited the proliferation of Roswell Park Memorial Institute (RPMI)-8226 cells by 96%, at 10 µM with IC50  = 9.09 ± 0.34 µM and selectivity index = 7.19 against normal blood cells. To confirm the selectivity of this compound, it was evaluated against a panel of tyrosine kinase enzymes. Mechanistically, it successfully and selectively inhibited HDAC6, HDAC8, and EGFR with IC50  = 0.41 ± 0.015, 0.61 ± 0.027, and 0.09 ± 0.004 µM, respectively. Furthermore, the selected derivative induced apoptosis via the mitochondrial apoptotic pathway by raising the Bax/Bcl-2 ratio and activating caspases 3, 7, and 9. Also, the flow cytometry analysis of RPMI-8226 cells showed that the trimethoxy-substituted analog produced cell cycle arrest in the G1 and S phases at 55.82%. Finally, an in silico study was performed to explore the binding interaction of the most active compound within the zinc-containing binding site of HDAC6 and HDAC8.

Acute exercise preferentially redeploys NK-cells with a highly-differentiated phenotype and augments cytotoxicity against lymphoma and multiple myeloma target cells

NK-cells undergo a "licensing" process as they develop into fully-functional cells capable of efficiently killing targets. NK-cell differentiation is accompanied by an increased surface expression of inhibitory killer immunoglobulin-like receptor (KIR) molecules, which is positively associated with cytotoxicity against the HLA-deficient K562 cell line. NK-cells are rapidly redeployed between the blood and tissues in response to acute exercise, but it is not known if exercise evokes a preferential trafficking of differentiated NK-cells or impacts NK-cell cytotoxic activity (NKCA) against HLA-expressing target cells. Sixteen healthy cyclists performed three 30-min bouts of cycling exercise at -5%, +5%, and +15% of lactate threshold. Blood samples obtained before, immediately after, and 1h after exercise were used to enumerate NK-cells and their subsets, and determine NKCA and degranulating subsets (CD107+) against cell lines of multiple myeloma (U266 and RPMI-8226), lymphoma (721.221 and 221 AEH), and leukemia (K562) origin by 4 and 10-color flow cytometry, respectively. Exercise evoked a stepwise redeployment of NK-cell subsets in accordance with differentiation status [highly-differentiated (KIR+/NKG2A-) >medium-differentiated (KIR+/NKG2A+)>low-differentiated (KIR-/NKG2A+)] that was consistent across all exercise intensities. NKCA per cell increased ∼1.6-fold against U266 and 221 AEH targets 1h post-exercise and was associated with a decreased proportion of NK-cells expressing the inhibitory receptor CD158b and increased proportion of NK-cells expressing the activating receptor NKG2C, respectively. We conclude that exercise evokes a preferential redeployment of NK-cell subsets with a high differentiation phenotype and augments cytotoxicity against HLA-expressing target cells. Exercise may serve as a simple strategy to enrich the blood compartment of highly cytotoxic NK-cell subsets that can be harvested for clinical use.

Targeting the Wnt/beta-catenin pathway in multiple myeloma

BACKGROUND/AIM

Recent investigations have shown that the Wnt signaling pathway is constitutively activated in multiple myeloma (MM), thereby promoting an exaggerated cell proliferation. Thus, influencing the Wnt pathway might represent a promising target in myeloma treatment.

MATERIALS AND METHODS

The present study investigated whether a combination of ethacrynic acid (EA) and ciclopirox olamine (CIC) with piceatannol (PIC) would influence the Wnt pathway and viability of human and murine myeloma cell lines by using DiOC6 and propidium iodide (PI) staining, flow cytometry and immunoblotting.

RESULTS

The combination of EA with PIC as well as the combination of CIC with PIC had a significant additive effect on the vitality of myeloma cells compared to single-agent application, while healthy cells remained mainly unaffected. Additionally, EA and CIC altered the expression of β-catenin itself and its downstream factors.

CONCLUSION

A combination of Wnt inhibitors could lead to novel treatment options for MM patients.