Potential lung cancer therapy using plant derived cholesterol structural analogs

Abstract

The acquired multidrug resistance syndrome (MDRS) is one of the leading causes for the failure of chemotherapy in lung cancer. Recently plant‐derived triterpenoids (eg, cholesterol‐structural analogs) have showed a wide spectrum of pharmacological activities. In addition, in different studies, anticancer agents have been combined to cholesterol moieties to improve their cellular uptake and target specificity. Herein, we investigated the cytotoxic activity of various triterpenoids cholesterol analogs: oleanolic acid (OleA), ursolic acid (UrA), betulinic acid (BeA), asiatic acid (AsA), lupeol (Lupe), stigmasterol (Stg) and β‐sitosterol (β‐Sito) on non‐small lung adenocarcinoma cells (A549) and normal lung cells (MRC5). From our studies, the IC 50 for most of these cholesterol‐analogs were in the low μM range after 24h of incubation. β‐Sito and Stg did not show any significant cytotoxic pattern in this μM range. In addition BeA and OleA showed the highest therapeutic indexes comparing the cytotoxic effect in A549 vs MRC5 cells. Metabolic activity assays were performed to determine the mechanism of action of these natural compounds. Caspases activity and cell membrane integrity assays were performed and all the cytotoxic triterpenoids induced no activation of caspase‐3, and high membrane permeabilization. Gene expression assays of MDRS‐related genes (EGF, VEGF, Pgp, Bcl‐2, P 53 , NDRG1, GLIPR1) demonstrated the downregulation of some of these genes after the incubation with these triterpenoids. These results demonstrated that even slight structural changes in these cholesterol analogs can influence the cytotoxic response and cellular mechanistic pathways. Complete results will be presented. This study opens promising perspectives for further research on the role of phytochemical triterpenoids, which ultimately will contribute to a more rational application in cancer therapy. Support or Funding Information SJB‐Research Center Seed