Kanglaite enhances the efficacy of cisplatin in suppression of hepatocellular carcinoma via inhibiting CKLF1 mediated NF-κB pathway and regulating transporter mediated drug efflux

Ethnopharmacological relevance: Kanglaite (KLT) is an active extract of the Coix lacryma-jobi seed, which can benefit Qi and nourish Yin, and disperse the accumulation of evils. It is used as a biphasic broad-spectrum anti-cancer drug, and shows synergistic effects with radiotherapy and chemotherapy. However, the mechanism of KLT combined with cisplatin (CDDP) against hepatocellular carcinoma (HCC) has not been elucidated.

Aim of the study: The aim of present study was to investigate the potential synergistic effects of KLT and CDDP on HepG2 cells, discussing the possible mechanisms from the perspective of CKLF1 and NF-κB mediated inflammatory response and chemoresistance, and the involvement of drug efflux transporters.

Materials and methods: CDDP injured HepG2 cells were used to investigate the effects of KLT on chemotherapeutics treated HCC. Effects of KLT pretreatment on CDDP injured HepG2 cells were determined by MTT, wound healing assay, and transwell assay. Expression of chemokine-like factor 1 (CKLF1) and activation of nuclear factor κB (NF-κB) were examined by qPCR, western blot, and immunofluorescence staining. Furthermore, to study the role of CKLF1 in KLT mediated effects on this CDDP injured HCC cell model, HepG2 cells overexpressed with CKLF1 gene were used. Cell viability and NF-κB activation were investigated. Moreover, TNF-α and IL-1β levels were measured by Elisa analysis and western blot to evaluate the inflammatory response. Additionally, ATP-binding cassette (ABC) drug efflux transporters, MDR1, MRP2, and BCRP were also determined in present study.

Results: KLT pretreatment followed by CDDP treatment was found to show synergistic effects, which showed by decreased cell viability, migration and invasion ability of HepG2 cells. Expression of CKLF1 enhanced significantly in CDDP treated HepG2 cells, and KLT decreased this elevation obviously. Furthermore, CDDP activated NF-κΒ and promoted translocation of NF-κB toward the nucleus. KLT inhibited the activation of NF-κΒ, which sensitized cancer cells. Overexpression of CKLF1 reversed the effects of KLT on CDDP injured HepG2 cells, which exhibited by increased cell viability and enhanced activation of NF-κΒ. CDDP induced NF-κΒ activation could also lead to excessive inflammatory response, and KLT can suppress the aggravating inflammation which may be beneficial for tumor progression. Furthermore, we found that ABC drug efflux transporters MDR1, MRP2, and BCRP in CDDP treated HepG2 cells were decreased when pretreated with KLT.

Conclusions: KLT pretreatment may increase the effects of CDDP on HepG2 cells, by exhibiting cooperative effects on suppression of HepG2 cells. The mechanisms may partly by inhibiting CKLF1 mediated NF-κB pathway, which may contribute to inflammation of tumor microenvironment and chemoresistance of CDDP. Inhibition of transporter-mediated drug efflux is also involved in KLT mediated sensitization effects of CDDP.

Keywords: CKLF1; Chemoresistance; Cisplatin; Hepatocellular carcinoma; Inflammation; Kanglaite.