Etoposide and doxorubicin enhance the sensitivity of triple negative breast cancers through modulation of TRAIL-DR5 axis

Abstract

Death receptor 5 (DR5) is an important target for development of anticancer agents against triple-negative breast cancer (TNBC). Recently, we reported the molecular level details for the modulation of TRAIL-DR5 axis by quinacrine (QC) in breast cancer cells. In this work, the DR5 mediated anticancer potential of topoisomerase inhibitor etoposide (ET) and doxorubicin (DOX) against TNBC has been evaluated. ET and DOX enhanced the DR5 expression in TNBC cells, whereas non-topoisomerase inhibitors pifithrin-α (PIF) and dexamethasone (DEX) failed to do so. In the TRAIL pre-treated cells, ET and DOX induced higher apoptosis, indicating their synergistic effect with TRAIL. The molecular docking and molecular dynamics studies showed their ability to stabilize the TRAIL-DR5 complex, whereas PIF and DEX failed to do so. The binding energy for TRAIL-DR5 complexation in the ternary complexes containing ET (-111.08 kcal/mol) and DOX (-76.35 kcal/mol) were higher than reported binding energy of binary complex (-53.70 kcal/mol). The in silico and in vitro mutational studies highlighted the importance of DR5 residue SerB68 in mediating the receptor-drug interaction. ET and DOX failed to enhance apoptosis in DR5 knockdown (DR5-KD) cells. On the other hand, TRAIL+ET exhibited induction of DR5 and subsequent apoptosis in WT-DR5 overexpressed DR5-KD cells, by modulating the mitochondrial intrinsic apoptosis cascade. An induction of apoptosis and DR5 expression was noticed in xenograft mice and in TNBC patient-derived metastatic cells after TRAIL+ET treatment. Thus, data suggests ET and DOX act as DR5 agonistic ligands and enhance the cellular apoptosis in TNBC.

Anti-cancer therapeutic benefit of red guava extracts as a potential therapy in combination with doxorubicin or targeted therapy for triple-negative breast cancer cells

“…Combination treatment of etoposide and doxorubicin can enhance cytotoxicity in TNBCs through the TRAIL-DR5 axis [25]. In addition, TRAIL signals can increase NF-kB activity [35], and guava extracts can regulate NF-kB activity [3].…”

“…Red guavas were kindly provided by a farmer, Lin Chao Hsiung (A Fong guava farm, Houbi Dist., Tainan City 731, Taiwan). Doxorubicin, Erlotinib (Tarceva; Roche, Basel, Germany) and Gefitinib (Iressa; Astra Zeneca, London, England) were dissolved in dimethyl sulfoxide (DMSO) and the concentrations of drugs were referred to previous studies [15,25,30]…”

“…However, doxorubicin is not effective for TNBC treatment. Other agents may be used to enhance doxorubicin-induced anti-cancer activity on TNBC [25]. Tarceva (Erlotinib) and Iressa (Gefitinib), both of which are EGFR inhibitors, are used as targeted therapy for breast and other cancers [26,27].…”

Integration of Molecular Docking and In Vitro Studies: A Powerful Approach for Drug Discovery in Breast Cancer

“…In vitro, in silico, in vivo, and ex vivo analyses have been performed to evaluate the cytotoxic action of etoposide (ET), doxorubicin (DOX), pifithrin-α (PIF), and dexamethasone (DEX) in triple-negative BC (TNBC) [21]. TNBC is a molecular subtype of BC that is negative for three hormone receptors-namely, estrogen receptors (ERs), progesterone receptors (PRs), and human epidermal receptor 2 (HER2) [21].…”

“…In vitro, in silico, in vivo, and ex vivo analyses have been performed to evaluate the cytotoxic action of etoposide (ET), doxorubicin (DOX), pifithrin-α (PIF), and dexamethasone (DEX) in triple-negative BC (TNBC) [21]. TNBC is a molecular subtype of BC that is negative for three hormone receptors-namely, estrogen receptors (ERs), progesterone receptors (PRs), and human epidermal receptor 2 (HER2) [21]. ET, a podophyllotoxin derivative, is a chemotherapy medication used against a wide range of cancers (e.g., lung cancer, lymphoma, lung cancer, leukemia, and glioblastoma multiforme), but its efficacy against TNBC is still unknown [22].…”