Induction of apoptosis on human hepatocarcinoma cell lines by an alkyl resorcinol isolated fromLithraea molleoides

Abstract

INTRODUCTIONHepatocellular carcinoma is the 5 th most common cancer in the world and the 4 th most common cause of cancer-associated mortality [1] . Surgical resection and local treatment are frequently limited, as a result of metastasis, cirrhosis, and other pathological changes in the liver parenchyma. The development of chemotherapeutic or chemopreventive agents for hepatocellular carcinoma is important to reduce the mortality caused by this disease. Since cell homeostasis depends on the balance between proliferation and apoptosis, effective compounds inducing apoptosis appear to be a relevant strategy to suppress tumor growth [2] . Cytotoxic drugs cause cell death in sensitive cells, at least partly, by induction of apoptosis.The Anacardiaceae family comprises many medicinal species from which a number of biologically active substances, such as various phenolic lipids (alkylresorcinols, alkylphenols, alkylcatechols), have been isolated. These compounds present antibacterial, fungicidal and cytotoxic properties [3,4] . In addition, cytotoxic activity on tumor cells (B-16, PC-13, L-5178Y, P-388 and Hep-2) and antitumor activity against S-180 tumors in mice have been reported [5,6] . Lithraea molleoides (Vell.) Engl, a member of the Anacardiaceae family, is a Southamerican tree that grows in Argentina, Brazil and Uruguay [7,8] . We have previously reported cytotoxic activity for the methanol extract of L. molleoides on HepG2 cells [9] . Further activity-guided fractionation of the dichloromethane extract has led to the isolation of a pure bioactive compound, a new cytotoxic 5-alkyl resorcinol (5-AR) derivative: 1,3-dihydroxy-5-(tridec-4',7'-dienyl) benzene [10] . The aim of the present study was to analyze the mechanism of cytotoxicity of this compound, by studying apoptosis induction on treated HepG2 and Hep3B hepatoma cell lines. MATERIALS AND METHODS Isolation and identification of the compound METHODS:Human hepatocarcinoma cell lines (HepG2 and Hep3B) in culture were treated with inhibitory concentrations, 50% of the compound, for 24 h. The induction of apoptosis was detected in treated cells by analysis of DNA fragmentation, DNA content, and acridine orange and propidium iodide staining. RESULTS:After 24 h of 5-alkyl resorcinol treatment, both cell lines showed: (1) the typical morphological alterations of apoptosis; (2) DNA fragmentation, detected by laddering and appearance of a subG0 population by flow cytometry; and (3) condensed and fragmented nuclei by acridine orange-propidium iodide staining. CONCLUSION:Based on the results, this compound exerts its cytotoxic effect in both hepatocellular cell lines through apoptotic cell death. For Hep3B, cells with mutated p53 and Fas, apoptosis would proceed by p53-or Fas-independent pathways.

Studies on synthetic and structural characterization of new fluorine substituted phthalides of pharmaceutical interest

“…Both of these two compounds are reported to be associated with antibacterial 19,20 and anticancer 21,22 properties. Resorcinol structure is present in large number of compounds of therapeutic value showing anticancer 23,24 and antifungal activity 25,26 . A novel series of quinols with heteroaromatic or (arylsulphonyl) indole substitution at 4 position has been reported to show in vitro antitumour activity 27 .…”

The protozoan toxin climacostol and its derivatives: Cytotoxicity studies on 10 species of free-living ciliates

“…To date, several compounds that show antimicrobial, antiparasitic, antitumoral and genotoxic activities have been identified among the alkylresorcinols (Picardo et al 1987;Lytollis et al 1995;Singh et al 1995;Kozubek et al 2001). In addition, their potential use in the therapy and/or prevention of specific classes of diseases has attracted particular attention (Itokawa et al 1989;Suresh & Ray 1990;Gasiorowsky et al 1996;Kozubek et al 2001;Filip et al 2002;Barbini et al 2006). Up to the present time, the cytotoxic activity of climacostol was assayed on a panel of protozoa, flatworms and crustacea, as well as on human cancer and non-cancer cell lines (Miyake et al 2003;Buonanno 2005;Buonanno et al 2008).…”

Dietary alkylresorcinols and cancer prevention: a systematic review

“…The antioxidant property of ARs as polyphenolic compounds originates from the ability of their hydroxyl groups to donate H to a free radical, or to donate one electron to an alkyl free radical, which breaks the chain reaction of lipid peroxidation. Thus, ARs may modulate cellular redox state and protect proteins, phospholipids, DNA, RNA, and carbohydrates against peroxidation [82,84,85,87].…”

“…Ten in vitro studies [58,84,[96][97][98][99][100][101][102][103] were identified and included in the analysis of natural and synthetic ARs for activities that inhibit growth of human cancer cells ( Table 2). The studies focused on isolation and identification of naturally occurring ARs and their synthesis.…”

“…Another study demonstrated the cytotoxic effect of 5-alkylresorcinol (5-AR) isolated from L. molleoides leaves in the human hepatocarcinoma cell lines HepG2 and Hep3B [84]. Treatment of both cell lines with 5-AR for 24 h resulted in induction apoptosis, DNA fragmentation, and nuclear condensation.…”