dihydropyridines and Stomach-Neoplasms

Elevated expression of YY1 is known to confer anti-apoptotic phenotype and hence is an attractive target for cancer therapeutics. In a repurpose screening, towards the identification of the inhibitors of YY1 regulated transcription in gastric cancer cells, the calcium channel blockers lercanidipine and amlodipine have been identified to inhibit YY1 more efficiently. We further probed these calcium channel blockers for their potential feature of alleviating the drug resistance in gastric cancer cells. Lercanidipine and amlodipine were found to show an enhanced effect with doxorubicin in inhibiting the growth of gastric cancer cells. While doxorubicin was identified to activate the pathways TGF-β and ERK/MAPK, lercanidipine was found to inhibit these pathways. This being the molecular mechanism behind the identified advantage of lercanidipine and amlodipine in sensitizing gastric cancer cells to doxorubicin. In multiple cellular models from different lineages, the cells with less sensitivity to doxorubicin were found to have the inherent activation of ERK/MAPK and TGF-β pathways. Also, we have identified that doxorubicin, in combination with any of the calcium channel blockers, could inhibit the potential of cellular proliferation and spheroid formation in gastric cancer cells. The current study shows the usefulness of lercanidipine and amlodipine for the targeted and combinatorial therapeutics of gastric cancer and specifically to improve the efficiency of doxorubicin.

Topics: Amlodipine; Antibiotics, Antineoplastic; Calcium Channel Blockers; Cell Line; Cell Survival; Dihydropyridines; Doxorubicin; Drug Synergism; Extracellular Signal-Regulated MAP Kinases; Humans; Stomach Neoplasms; Transcription, Genetic; Transcriptome; Transforming Growth Factor beta; YY1 Transcription Factor

P-glycoprotein (P-gp) is one of the cell membrane pumps which mediate the efflux of molecules such as anticancer drugs to the extracellular matrix of tumor cells. P_gp is a member of the ATP-binding cassette (ABC) transporter family that is implicated in cancer multidrug resistance (MDR). Since MDR is a contributor to cancer chemotherapy failure, modulation of efflux pumps is a viable therapeutic strategy. In this study, new synthetic 1,4 dihydropiridine (DHP) derivatives containing thiophenyl substitution were tested as inhibitors of P-gp. Efflux assay was conducted to evaluate the intracellular accumulation of Rhodamine123 (Rh123) as a pump substrate. MTT assay, cell cycle analysis and in silico methods were also examined. Flow cytometric analysis revealed that synthetic DHP derivatives (15 µM) increased intracellular concentration of the substrate by 2-3 folds compared with verapamil as a standard P-gp inhibitor. MTT assay on EPG85-257P and its drug-resistant EPG85-257RDB cell line revealed antitumor effects (30-45%) for new DHP derivatives at 15 µM following 72 h incubation. However, MTT test on normal cell line showed negligible toxic effects. Finally combination of synthetic derivatives with doxorubicin showed that these compounds decrease IC50 of doxorubicin in resistant cell lines from 9 to 1.5 µM. Sub-G1 peak-related apoptotic cells showed a stronger effect of synthetic compounds at 5 µM compared with verapamil. Molecular dynamic results showed a high binding affinity between DHP derivative and protein at drug binding site. Findings of these biological tests indicated the antitumor activity and P-gp inhibitory effects of new 1,4-DHP derivatives.

Topics: Antibiotics, Antineoplastic; Antineoplastic Agents; ATP Binding Cassette Transporter, Subfamily B, Member 1; Cell Cycle; Cell Proliferation; Computer Simulation; Dihydropyridines; Doxorubicin; Drug Resistance, Neoplasm; Humans; In Vitro Techniques; Stomach Neoplasms; Tumor Cells, Cultured