2’-Hydroxyflavanone effectively targets RLIP76-mediated drug transport and regulates critical signaling networks in breast cancer

Abstract

Breast cancer (BC) is the most common cancer in women. Estrogen, epidermal growth factor receptor 2 (ERBB2, HER2), and oxidative stress represent critical mechanistic nodes associated with BC. RLIP76 is a major mercapturic acid pathway transporter whose expression is increased in BC. In the quest of a novel molecule with chemopreventive and chemotherapeutic potential, we evaluated the effects of 2'-Hydroxyflavanone (2HF) in BC. 2HF enhanced the inhibitory effects of RLIP76 depletion and also inhibited RLIP76-mediated doxorubicin transport in BC cells. RNA-sequencing revealed that 2HF induces strong reversal of the gene expression pattern in ER+MCF7, HER2+ SKBR3 and triple-negative MDA-MB-231 BC cells with minimal effects on MCF10A normal breast epithelial cells. 2HF down regulated ERα and enhanced inhibitory effects of imatinib mesylate/Gleevec in MCF7 cells. 2HF also down regulated ERα and HER2 gene networks in MCF7 and SKBR3 cells, respectively. 2HF activated TP53 and inhibited TGFβ1 canonical pathway in MCF7 and MDA-MB-231 BC cells. 2HF also regulated the expression of a number of critical prognostic genes of MammaPrint panel and their upstream targets including TP53, CDKN2A and MYC. The collective findings from this study provide a comprehensive, direct and integrated evidence for the benefits of 2HF in targeting major and clinically relevant mechanistic regulators of BC.

2′‐Hydroxyflavanone inhibits in vitro and in vivo growth of breast cancer cells by targeting RLIP76

“…We found that compared to control, 2HF alone inhibited BC cell proliferation in vitro and reduced tumor growth and weight in vivo. In addition, 2HF suppressed in vitro and in vivo levels of RLIP76 proteins, aberrant expression of which has been reported in various cancer types . The striking finding was that RLIP76 could be a biologically relevant target of 2HF in BC cells as over‐expression of RLIP76 caused a sustained decrease in the efficacy of 2HF across all time points tested (GFP‐RLIP76 + 2HF as compared to 2HF, Figure B).…”

“…The rationale for selecting RLIP76 as one of the targets of 2HF stems from the following observations. First, RLIP76 is a selectively over‐expressed in cancer cells . Second, blocking of RLIP76 with antibodies or depleting with antisense increases sensitivity to chemotherapy and results in significant tumor reduction in colon, prostate, and lung carcinomas and B16 melanomas in mice.…”

“…Numerous studies have reported the association between decreased expression of RLIP76 and reduced cell survival in various human neoplasms both in vitro and in vivo (23)(24)(25)(26)(27)(28)(32)(33)(34)(35). To verify the role of RLIP76 in mediating the anti-growth effects of 2HF, the expression was interesting to note that 2HF treatment led to a remarkable decrease in proliferation of BC cells over-expressing RLIP76 ( Figure 4B).…”

“…2HF strongly inhibited the ER α and HER2 networks in MCF7 and SKBR3 cells along with inhibiting IGF1 and macropinocytosis canonical pathways in MDA‐MB231 cells. Overall, the efficacy and mechanistic spectrum of the effects of 2HF on ER α , HER2, and MammaPrint prognostic gene networks in different molecular backgrounds of BC collectively provide strong rationale for translational development of 2HF in BC . Therefore, in the present study, we investigated the in vitro and in vivo anticancer efficacy of 2HF in MCF7 (ER‐positive) and SKRB3 (HER2‐positive) BC cells.…”

“…Overall, the efficacy and mechanistic spectrum of the effects of 2HF on ERα, HER2, and MammaPrint prognostic gene networks in different molecular backgrounds of BC collectively provide strong rationale for translational development of 2HF in BC. 32 Therefore, in the present study, we investigated the in vitro and in vivo anticancer efficacy of 2HF in MCF7 (ER-positive) and SKRB3 (HER2-positive) BC cells. This study focused on the ability of 2HF to inhibit the growth of BC cells, and determined that its antitumor properties could be via its ability to inhibit RLIP76 and its associated downstream signaling pathways.…”