Profiling the Complexity of Resistance Factors in Cancer Cells Towards Berberine and Its Derivatives

<b>Background:</b> Berberine, a benzylisoquinoline alkaloid, has been traditionally used in Ayurvedic and Chinese medicine. We examined the resistance mechanisms to berberine in a panel of different cancer cells and focused on understanding its molecular mechanisms. <b>Methods:</b> Resazurin assay determined berberine's cytotoxicity. Molecular docking unraveled the interaction of berberine with the BCRP transporter. Fluorescence microscopy evaluated its effect on microtubules. Further, proteomic profiling identified novel determinants of cellular response to berberine and its derivatives. <b>Results:</b> Cell lines overexpressing ABC transporters displayed cross-resistance to berberine compared to their counterparts. While cells over-expressing EGFR were 3.57-fold resistant, wild-type and p53 knockout cells showed similar sensitivity to berberine. P-glycoprotein/<i>ABCB1</i>, <i>EGFR</i>, and <i>WT1</i> expression correlated with the log₁₀IC₅₀ values for berberine in the NCI cell line panel. Berberine was bound to the same pharmacophore of BCRP as BWQ, and live cell microscopy showed that <i>BCRP</i>-transfected cells did not uptake considerable amounts of berberine in contrast to wild-type cells. Berberine altered the microtubule cytoskeleton similarly to vincristine. The sensitivity of berberine and its derivatives could be predicted by 40 out of 3171 proteins. Of them, 29 proteins have been previously involved in drug resistance. Their relationship to berberine and its derivatives is novel. <b>Conclusions:</b> Berberine-type compounds may be new candidates against cancer; however, they may develop drug resistance.