Hedyotis diffusa Willd overcomes 5-fluorouracil resistance in human colorectal cancer HCT-8/5-FU cells by downregulating the expression of P-glycoprotein and ATP-binding casette subfamily G member 2

Abstract

Abstract. Previous studies have demonstrated thatHedyotis diffusa Willd (HDW), a traditional Chinese herbal medicine, exhibits potent anticancer activity in models of colorectal cancer (CRC). Aggressive forms of CRC exhibit resistance to widely used chemotherapeutic drugs, including the antimetabolite, 5-fluorouracil (5-FU); however, less is known with regard to the activity of HDW against 5-FU-resistant cancer. In the present study, the mechanism of action and the potency of ethanol extracts of HDW (EEHDW) were investigated on a multidrug-resistant CRC HCT-8/5-FU cell line. Using an MTT cell proliferation assay, EEHDW treatment was shown to significantly reduce the cell viability of HCT-8/5-FU cells in a dose-and time-dependent manner. Furthermore, EEHDW significantly increased the retention of the ATP-binding cassette (ABC) transporter substrate, rhodamine-123, as compared with the untreated controls. To further investigate the molecular mechanisms targeted by EEHDW in the resistant cells, the expression levels of the ABC drug transporter protein, P-glycoprotein (P-gp), and ABC subfamily G member 2 (ABCG2), were analyzed using reverse-transcription polymerase chain reaction and western blot analysis. The mRNA and protein expression levels of P-gp and ABCG2 were reduced in the HCT-8/5-FU cells following EEHDW treatment, indicating that EEHDW inhibits ABCG2-mediated drug resistance by downregulating the expression of ABCG2 and P-gp. Therefore, the potential application of EEHDW as a chemotherapeutic adjuvant represents a promising alternative approach to the treatment of drug-resistant CRC.

The Hedyotis diffusa Willd. (Rubiaceae): A Review on Phytochemistry, Pharmacology, Quality Control and Pharmacokinetics

“…Meanwhile, the ethanolic extract of H. diffusa displayed an inhibition effect on CT-26 cells with inhibitory rates from 35.46%˘3.59% to 71.84%˘3.12% at different concentrations (0.06 mg/mL, 0.08 mg/mL, 0.10 mg/mL, 0.12 mg/mL, 0.14 mg/mL, 0.16 mg/mL, 0.18 mg/mL and 0.20 mg/mL) and showed a stronger inhibition effect with an increase of concentration [60]. Li et al [61] revealed that the ethanolic extract treatment could overcome 5-fluorouracil resistance in HCT-8/5-FU cells by downregulating the expression of P-gp and ABCG2. In addition, 2-hydroxymethy-1-hydroxy anthraquinone (IC 50 45 µM) and ursolic acid (IC 50 71 µM)) isolated from H. diffusa exhibited inhibition effects on Caco-2 cell proliferation [5], and the mechanism of the inhibition effect for ursolic acid might include the cleavage of the Poly (ADP-ribose) Polymerase (PARP) [62].…”

Synergistic inhibition of leukemia WEHI-3 cell growth by arsenic trioxide and Hedyotis diffusa Willd extract in vitro and in vivo

“…HDW is used as a cancer therapy agent, which reduces the adverse reactions of chemotherapy (12). Several reports have demonstrated that the extract of HDW exerts its therapeutic effects by inducing mitochondrial apoptosis in numerous human cancer cell lines (13–15).…”

Hedyotis diffusa willd extract suppresses colorectal cancer growth through multiple cellular pathways

“…HDW has also been widely used as an important component in traditional Chinese medicine (TCM) prescription formulae for the treatment of various types of cancer, including CRC (17)(18)(19). Our previous studies have demonstrated that HDW is able to inhibit colon cancer growth in vivo and in vitro by promoting apoptosis of cancer cells, inhibiting proliferation, tumor angiogenesis and MDR reversal (20)(21)(22)(23)(24)(25). However, the precise mechanism of the in vivo anti-cancer activity of HDW remains largely unknown.…”