Anacardic acid induces cell apoptosis of prostatic cancer through autophagy by ER stress/DAPK3/Akt signaling pathway.

Anacardic acid, which is commonly seen in plants of Anacardiaceae, is an important composition of cashew, ginkgo leaf and fruit, and it has been suggested in previous research to show antitumor activity. The main aim of the present study was to evaluate the anticancer effects of anacardic acid on cell apoptosis of prostatic cancer and molecular mechanisms of this phenomenon. In this study we found that anacardic acid inhibited cell proliferation, induced apoptosis and caspase-3/9 activities and Bax protein expression of prostatic cancer. Anacardic acid induced the ER stress inducing factors (BiP, CHOP, p-eIF2α), autophagy, LC3, Beclin-1, Atg 7 and DAPK3 protein expression, and suppressed p-Akt and p-mTOR protein expression of prostatic cancer. Si-CHOP was used to inhibit ER stress in prostatic cancer by anacardic acid, which showed that the cell proliferation was increased, apoptosis, and caspase-3/9 activities and Bax protein expression was suppressed, autophagy, LC3, Beclin-1, Atg 7 and DAPK3 protein expression was reduced, and p-Akt and p-mTOR protein expression was promoted. DAPK3 inhibited p-Akt and p-mTOR protein expression, enhanced the anticancer effects of anacardic acid on prostatic cancer through autophagy. For the first time, the present study showed that anacardic acid induces cell apoptosis of prostatic cancer through autophagy by ER stress/DAPK3/Akt signaling pathway.

Combinatorial treatment with anacardic acid followed by TRAIL augments induction of apoptosis in TRAIL resistant cancer cells by the regulation of p53, MAPK and NFκß pathways.

TRAIL, an apoptosis inducing cytokine currently in phase II clinical trial, was investigated for its capability to induce apoptosis in six different human tumor cell lines out of which three cell lines showed resistance to TRAIL induced apoptosis. To investigate whether Anacardic acid (A1) an active component of Anacardium occidentale can sensitize the resistant cell lines to TRAIL induced apoptosis, we treated the resistant cells with suboptimal concentration of A1 and showed that it is a potent enhancer of TRAIL induced apoptosis which up-regulates the expression of both DR4 and DR5 receptors, which has been observed in the cellular, protein and mRNA levels. The death receptors upregulation consequent to A1 treatment was corroborated by the activation of p53 as well as phosphorylation of p38 and JNK MAP kinases and concomitant inactivation of NFκß and ERK signaling cascades. Also, A1 modulated the expression of key apoptotic players like Bax, Bcl-2 and CAD along with the abatement of tumor angiogenesis in vivo in EAT mouse model. Thus, post A1 treatment the TRAIL resistant cells turned into TRAIL sensitive cells. Hence our results demonstrate that A1 can synergize TRAIL induced apoptosis through the upregulation of death receptors and downregulation of anti-apoptotic proteins in cancer context.

Anacardic acid enhances the anticancer activity of liposomal mitoxantrone towards melanoma cell lines - in vitro studies.

THIS PAPER DESCRIBES A NOVEL FORMULATION OF ANTINEOPLASTIC DRUG: mitoxantrone loaded into liposomal carriers enriched with encapsulated anacardic acid in the liposomal bilayer using a vitamin C gradient. Anacardic acid is a potent epigenetic agent with anticancer activity. This is the first liposomal formulation to combine an actively encapsulated drug and anacardic acid. The liposomes were characterized in terms of basic parameters, such as size, zeta potential, optimal drug-to-lipid ratio, loading time and temperature, and stability at 4°C and in human plasma in vitro. The formulation was found to be stable, and the loading process was rapid and efficient (drug-to-lipid ratio of up to 0.3 with over 90% efficiency in 5 minutes). The cytotoxicity of these formulations was assessed using the human melanoma cell lines A375 and Hs294T and the normal human dermal fibroblast line. The results showed that anacardic acid and to a smaller extent vitamin C significantly increased the cytotoxicity of the drug towards melanoma compared to ammonium sulfate liposomes. On the other hand, vitamin C and anacardic acid both protected normal cells from damage caused by the drug. The formulation combining anacardic acid, vitamin C, and mitoxantrone showed promising results in terms of cytotoxicity and cytoprotection. Therefore, it has potential for anticancer treatment.

Lunasin-aspirin combination against NIH/3T3 cells transformation induced by chemical carcinogens.

Carcinogenesis is a multistage process involving a number of molecular pathways sensitive to intervention. Chemoprevention is defined as the use of natural and/or synthetic substances to block, reverse, or retard the process of carcinogenesis. To achieve greater inhibitory effects on cancer cells, combination of two or more chemopreventive agents is commonly considered as a better preventive and/or therapeutic strategy. Lunasin is a promising cancer preventive peptide identified in soybean and other seeds. Its efficacy has been demonstrated by both in vitro and in vivo models. This peptide has been found to inhibit human breast cancer MDA-MB-231 cells proliferation, suppressing cell cycle progress and inducing cell apoptosis. Moreover, lunasin potentiates the effects on these cells of different synthetic and natural compounds, such as aspirin and anacardic acid. This study explored the role of lunasin, alone and in combination with aspirin and anacardic acid on cell proliferation and foci formation of transformed NIH/3T3 cells induced by chemical carcinogens 7,12-dimethylbenz[a]anthracene or 3-methylcholanthrene. The results revealed that lunasin, acting as a single agent, inhibits cell proliferation and foci formation. When combined with aspirin, these effects were significantly increased, indicating that this combination might be a promising strategy to prevent/treat cancer induced by chemical carcinogens.

Anti-Helicobacter pylori activity of anacardic acids from Amphipterygium adstringens.

Amphipterygium adstringens (Schltdl.) Standl. (Anacardiaceae) is widely used in traditional Mexican medicine for the treatment of gastritis and ulcers. In this work, we studied the anti-Helicobacter pylori activity of its bark, this Gram-negative bacterium is considered the major etiological agent of chronic active gastritis and peptic ulcer disease, and it is linked to gastric carcinoma. From a bio-guided assay of the fractions obtained form a continuous Soxhlet extraction of the bark, we identified that petroleum ether fraction had significant antimicrobial activity against Helicobacter pylori. From this fraction, we isolated an anacardic acids mixture and three known triterpenes: masticadienonic acid; 3alpha-hydroxymasticadienonic acid; 3-epi-oleanolic; as well as the sterol beta-sitosterol. Only the anacardic acids mixture exhibits a potent dose-dependent antibacterial activity (MIC=10 microg/ml in broth cultures). It is enriched in saturated alkyl phenolic acids (C15:0, C16:0, C17:0 C19:0) which represents a novel source of these compounds with potent anti-Helicobacter pylori activity. The promising use of anacardic acids and Amphipterygium adstringens bark in the development of an integral treatment of Helicobacter pylori diseases is discussed.