Anacardic acid induces caspase-independent apoptosis and radiosensitizes pituitary adenoma cells

Anacardic 6-pentadecyl salicylic acid induces apoptosis in breast cancer tumor cells, immunostimulation in the host and decreases blood toxic effects of taxol in an animal model

Many antineoplastic agents induce myelosuppression and leukopenia as secondary effects in patients. The development of anticancer agents that simultaneously provoke antitumor immune response represents an important therapeutic advance. The administration of 6-pentadecyl salicylic acid (6SA) contributes to the antitumor immunity using 4T1 breast cancer cells in Balb/c female mice, with Taxol as a positive control and in cotreatment with 6SA (6SA + Taxol; CoT). Our results show that 6SA reduces tumor volume and size by inducing caspase-8-mediated apoptosis without reducing tumor infiltrated lymphocytes. Also, 6SA reduced lung metastasis and increased the proportion of immune cells in blood, lymph nodes and bone marrow; more evidently, in the proportion of tumor-infiltrated natural killer (NK) cells and cytotoxic T lymphocytes. Taxol reduces helper and cytotoxic lymphocytes causing systemic immunosuppression and myelosuppression in bone marrow, whereas 6SA does not decrease any immune cell subpopulations in circulating blood and lymph nodes. More importantly, the CoT decreased the Taxol-induced cytotoxicity in circulating T cells and bone marrow. Treatment with 6SA increases the secretion of IL-2, IL-12, GM-CSF, TNF-α and IFN-γ and significantly reduces IL-10 and IL-17 secretion, suggesting that the reduction of regulatory T cells and tumor-associated macrophages contribute to the host control of tumor development. Finally, 6SA has an effective antineoplastic activity against breast cancer cells in an immunocompetent animal, reduces the myelosuppression and leukopenia that Taxol produces, improves the antitumoral immunological microenvironment and increases the overall survival of the animals improving the quality of life of patients with cancer.

The Anti-Inflammatory Effects of Anacardic Acid on a TNF-α - Induced Human Saphenous Vein Endothelial Cell Culture Model

BACKGROUND AND OBJECTIVE

Coronary bypass operations are commonly performed for the treatment of ischemic heart diseases. Coronary artery bypass surgery with autologous human saphenous vein maintains its importance as a commonly used therapy for advanced atherosclerosis. Vascular inflammation-related intimal hyperplasia and atherosclerotic progress have major roles in the pathogenesis of saphenous vein graft disease.

METHODS

In our study, we investigated the effect of anacardic acid (AA), which is a bioactive phytochemical in the shell of Anacardium occidentale, on atherosclerosis considering its inhibitory effect on NF-κB. We observed relative ICAM-1 and NF-κB mRNA levels by qRT-PCR method in a TNF-α- induced inflammation model of saphenous vein endothelial cell culture after 0.1, 0.5, 1 and 5 μM of AA were applied to the cells. In addition, protein levels of ICAM-1 and NF-κB were evaluated by immunofluorescent staining. The results were compared between different concentrations of AA, and also with the control group.

RESULTS

It was found that 5 μM, 1 μM and 0.5 μM of AA had toxic effects, while cytotoxicity decreased when 0.1 μM of AA was applied both alone and with TNF-α. When AA was applied with TNF-α, there was a decrease and suppression in NF-κB expression compared with the TNF-α group. TNF-α-induced ICAM-1 expression was significantly reduced more in the AA-applied group than in the TNF-α group.

CONCLUSION

In accordance with our results, it can be said that AA has a protective role in the pathogenesis of atherosclerosis and hence in saphenous vein graft disease.

Cashew apple (Anacardium occidentale L.) extract from a by-product of juice processing: assessment of its toxicity, antiproliferative and antimicrobial activities

Cashew apple extract (CAE) is a product with intense yellow color obtained from residual fibers of juice processing. Although CAE is known to be rich in carotenoids and anacardic acids, the biological activities of this potential natural food colorant remain unexplored. The present study is the first to investigate the toxicity, antiproliferative and antimicrobial activities of the lyophilized CAE (L-CAE) and its encapsulated products, using maltodextrin (M-CAE) or cashew gum (CG-CAE) as carriers. In addition to their high carotenoid content, the phenolic contents in all materials was determined using UPLC-QTOF-MS^E. The acute toxicity was performed using adult zebrafish (Danio rerio); antiproliferative activity was assessed using seven different human tumor cell lines [U-251 (glioblastoma), MCF-7 (breast, adenocarcinoma), NCI-ADR/RES (multidrug-resistant ovarian adenocarcinoma), NCI-H-460 (lung, large cell carcinoma), PC-3 (prostate, adenocarcinoma), OVCAR-3 (ovarian adenocarcinoma), and HT-29 (colon, adenocarcinoma)] and an immortalized human keratinocyte (HaCaT) while the antimicrobioal activity was evaluated on Staphylococcus aureus ATCC 25923, Listeria monocytogenes ATCC 19115, Escherichia coli ATCC 25922 and Salmonella Typhimurium ATCC 51812 microorganisms. Both lyophilized and encapsulated CAE samples did not exert acute toxicity against zebrafish neither antiproliferative effect against human tumor and non-tumor cell lines. Further, L-CAE showed potential antimicrobial activity against Listeria monocytogenes, which was confirmed using electron microscopy. The current findings demonstrated that CAE is a potential source of bioactive compounds to use as an additive in the food industry.

Antioxidant, Antimicrobial, and Anticancer Effects of Anacardium Plants: An Ethnopharmacological Perspective

Anacardium plants have received increasing recognition due to its nutritional and biological properties. A number of secondary metabolites are present in its leaves, fruits, and other parts of the plant. Among the diverse Anacardium plants' bioactive effects, their antioxidant, antimicrobial, and anticancer activities comprise those that have gained more attention. Thus, the present article aims to review the Anacardium plants' biological effects. A special emphasis is also given to their pharmacological and clinical efficacy, which may trigger further studies on their therapeutic properties with clinical trials.

A Combined Proteomics and Bioinformatics Approach Reveals Novel Signaling Pathways and Molecular Targets After Intracerebral Hemorrhage

Intracerebral hemorrhage (ICH) is a non-traumatic cerebrovascular disorder with very high morbidity and mortality and regarded as one of the deadliest stroke subtypes. Notably, there is no effective treatment for ICH. Despite an overall increase in preclinical studies, the pathophysiology of ICH is complex and remains enigmatic. To this end, ICH was induced in male CD-1 mice and the ipsilateral brain tissue was characterized in an unbiased manner using a combination of proteomics and bioinformatics approaches. A total of 4833 proteins were revealed by quantitative proteomic analysis. Of those, 207 proteins exhibited significantly altered expression after ICH in comparison to sham. It was found that 46 proteins were significantly upregulated and 161 proteins were significantly downregulated after ICH compared to sham. The quantitative proteomics approach combined with bioinformatics revealed several novel molecular targets (cyclin-dependent-like kinase 5, E3 ubiquitin-protein ligase, protein phosphatase 2A-alpha, protein phosphatase 2A-beta, serine/threonine-protein kinase PAK1, alpha-actinin-4, calpain-8, axin-1, NCK1, and septin-4), and related signaling pathways, which could play roles in secondary brain injury and long-term neurobehavioral outcomes after ICH warranting further investigation.

Epigenetic dysregulation in pituitary tumors

Pituitary tumors are common intracranial neoplasms associated with significant morbidity due to hormonal dysregulation and neurologic symptoms. Somatic mutations are uncommon in sporadic pituitary adenomas, and only few monogenic conditions are associated with pituitary tumors. However, increasing evidence suggests that aberrant epigenetic modifications are found in pituitary tumors. In this review, we describe these mechanisms, including DNA methylation, histone modification and microRNA expression, and the evidence supporting their dysregulation in pituitary tumors, as well as their regulation of pro-tumorigenic genes. In addition, we provide an overview of findings from preclinical studies investigating the use of histone deacetylase inhibitors to treat pituitary adenomas and the need for further studies involving epigenetic drugs and functional characterization of epigenetic dysregulation.

Calebin-A induced death of malignant peripheral nerve sheath tumor cells by activation of histone acetyltransferase

BACKGROUND

Neurofibromatosis type 1 (NF1) is one of the most common hereditary neurocutaneous disorders. The malignant peripheral nerve sheath tumor (MPNST), transformed from NF1 related plexiform neurofibroma, is a rapidly growing and highly invasive tumor. No effective chemotherapeutic agent is currently available. Calebin-A is a derivative from turmeric Curcuma longa. Given the anti-inflammatory and anticancer potentials of curcumin, whether Calebin-A also had the tumoricidal effect upon MPNST cells is still elusive.

PURPOSE

To determine whether Calebin-A has the potential for anti-MPNST effect.

METHODS

The MTT and FACS analysis of normal Schwann (HSC) and MPNST cells have been employed to determine the tumoricidal effect of Calebin-A. The expression of the signal pathway molecules was assessed by Western blotting. The CHIP with quantitative PCR assay was performed to quantify the promoter DNA binding to acetylated histone 3 (acetyl H3). The enzyme activities of histone acetyltransferase (HAT) and deacetylase (HDAC) have been evaluated by commercial kits. The measurements of tumor size of the xenograft mouse model were also performed.

RESULTS

Calebin-A inhibited the proliferation of MPNST and primary neurofibroma cells in a dose-dependent manner. The flow cytometry analysis of the MPNST cells after treatment of 25 μm of Calebin-A demonstrated an increase of population in the G0/G1 phase but decrease in G2/M phase. Before treatment, the expression of Axl, Tyro3, and acetyl H3 was significantly higher in MPNST cells when compared to HSC. The expression of phosphorylated-AKT, -ERK1/2, survivin, hTERT, and acetyl H3 proteins were reduced after treatment. The CHIP assay shows the promoter DNA copies of survivin (BRIC5) and hTERT genes are significantly reduced post-treatment. The enzyme activity of HAT was significantly reduced, but not that of HDAC. Two HAT inhibitors, epigallocatechin-3-gallate (EGCG) and anacardic acid (AA) have also demonstrated a significant inhibitory effect on MPNST cells. Finally, the measurements of tumor size showed a significant reduction of the xenograft tumors after treatment of Calebin-A.

CONCLUSION

Both in vitro and in vivo studies showed Calebin-A could inhibit the proliferation of MPNST with suppression of survivin and hTERT. The reduced expression of these two factors might be through the epigenetic histone modification resulting from the decreased activity of HAT.

ALT cancer cells are specifically sensitive to lysine acetyl transferase inhibition

Some cancer cells elongate their telomeres through the ALT (alternative lengthening of telomeres) pathway, which is based on homologous recombination for the addition of telomere repeats without telomerase activity. General control non-derepressible 5 (GCN5) and P300/CBP-associated factor (PCAF), two homologous lysine acetyltransferases, exert opposite effects on the ALT pathway, inhibiting or favoring it respectively. Here we show that ALT cells are particularly sensitive to the inhibition of acetyltransferases activities using Anacardic Acid (AA). AA treatment recapitulates the effect of PCAF knockdown on several ALT features, suggesting that AA decreased the ALT mechanism through the inhibition of lysine transferase activity of PCAF, but not that of GCN5. Furthermore, AA specifically sensitizes human ALT cells to radiation as compared to telomerase-positive cells suggesting that the inhibition of lysine acetyltransferases activity may be used to increase the radiotherapy efficiency against ALT cancers.

Anacardic acid suppresses fibroblast-like synoviocyte proliferation and invasion and ameliorates collagen-induced arthritis in a mouse model

Anacardic acid, which is abundant in nutshell of Anacardium occidentale, has multiple pharmacological activities. In this study, we examined the therapeutic potential of anacardic acid in treating rheumatoid arthritis (RA). We explored the effects of anacardic acid on collagen-induced arthritis (CIA) in mice and on the proliferation and invasion of RA fibroblast-like synoviocytes (RA-FLSs). The underlying molecular mechanism was investigated. Anacardic acid treatment markedly suppressed paw swelling, joint destruction, and arthritis scores in CIA mice. The serum levels of tumor necrosis factor alpha (TNF- α) and interleutkin-1beta (IL- 1β) were significantly lowered by anacardic acid. In vitro assays demonstrated that anacardic acid impaired the proliferation and invasion abilities of RA-FLSs in the presence of TNF- α or IL- 1β. Western blot analysis revealed the reduction of Akt protein expression and phoshporylation in RA-FLSs by anacardic acid. However, the mRNA level of Akt remained unchanged. Anacardic acid treatment significantly increased the expression of miR-633 in RA-FLSs. Akt was identified as a novel target of miR-633. Overexpression of miR-633 significantly inhibited the proliferation and invasion of RA-FLSs, which was rescued by enforced expression of Akt. Depletion of miR-633 prevented anacardic acid-mediated suppression of proliferation and invasion of RA-FLSs, which was accompanied by increased expression of Akt protein. In conclusion, anacardic acid may serve as a promising agent in the treatment of RA.

MicroRNA-378 regulates cell proliferation and migration by repressing RNF31 in pituitary adenoma

MicroRNA-378 (miR-378) is dysregulated in multiple malignancies and is associated with tumor progression. However, the expression and mechanism of miR-378 in pituitary adenoma (PA) remains to be elucidated. In the present study, the role and mechanism of miR-378 in PA tumorigenesis and development was investigated. It was revealed that the levels of miR-378 expression were markedly downregulated in PA tissues. CCK-8 and wound healing assays revealed that transfection with miR-378 mimics was able to markedly inhibit the proliferation and migration of GH3 cells. Furthermore, quantitative polymerase chain reaction analysis demonstrated that ring finger protein 31 (RNF31) was upregulated in PA specimens and the levels of RNF31 expression was negatively regulated by miR-378. In addition, knockdown of RNF31 markedly suppressed cell proliferation and migration in GH3 cells. In conclusion, the present study provides a molecular basis for the function of miR-378/RNF31 in the progression of human PA, indicating a potential novel target for the treatment of PA.

Inhibitory effect of Ginkgol C17:1 on the biological behavior of tumor cells

Ginkgol C17:1 is a bioactive compound derived from Ginkgo biloba. In the present study, the effect and possible mechanisms of action of Ginkgol C17:1 on the biological behaviors of tumor cells were investigated. Whilst cell proliferation was assessed using the MTT assay, the behaviors of cell migration and invasion were explored using Transwell and modified Transwell assays. The results revealed that Ginkgol C17:1 significantly inhibited the proliferation, migration and invasion of human tumor cells in a dose-dependent manner. Furthermore, due to their associations with the biological behaviors of tumor cells, the protein expression of matrix metalloproteinase (MMP)-7, Ras homolog gene family, member A (RhoA) and phosphorylated-protein kinase B (Akt) was analyzed by western blotting. The results showed that the expression of the aforementioned proteins was decreased markedly following Ginkgol C17:1 treatment. The results of the present study suggested that Ginkgol C17:1 suppresses the biological behaviors of tumor cells by inhibiting the activation of the mitogen-activated protein kinase/MMP, Rho/Rho-associated protein kinase and phosphatidylinositol 3-kinase/Akt signaling pathways.

Bilobol inhibits the lipopolysaccharide-induced expression and distribution of RhoA in HepG2 human hepatocellular carcinoma cells

Recent studies have revealed the localization of RhoA protein in the cell nucleus, in addition to its distribution in the cytosol and cell membrane. The results of previous studies by our group indicated that nuclear RhoA expression is increased, or RhoA is transported into the nucleus, when cells become cancerous or damaged. Furthermore, application of the anticancer agent Taxol appeared to reduce nuclear RhoA localization, indicating an association between the nuclear translocation of RhoA and tumor progression. Bilobol is a traditional Chinese medicine ingredient, however, its anticancer effect has remained unclear. The present study aimed to demonstrate the anticarcinogenic action of bilobol against hepatocellular carcinoma, in order to lay the foundations for subsequent research into the mechanisms underlying its anticancer effects. In the present study, HepG2 cells were treated with lipopolysaccharide (LPS), to induce inflammation, and/or bilobol. By performing an ELISA, it was observed that bilobol was able to suppress the inflammation induced by LPS. In addition, immunofluorescence and western blot analyses indicated that bilobol may reduce the expression of RhoA, suppress translocation of RhoA into the nucleus and inhibit the RhoA/Rho-associated protein kinase signaling pathway. In conclusion, the present study revealed the potential anticancer effects of bilobol.

Overexpression of Nrf2 attenuates Carmustine-induced cytotoxicity in U87MG human glioma cells

Background

Malignant glioma is one of the most devastating tumors in adults with poor patient prognosis. Notably, glioma often exhibits resistance to conventional chemotherapeutic approaches, complicating patient treatments. However, the molecular mediators involved in tumor chemoresistance remain poorly defined, creating a barrier to the successful management of glioma. In the present study, we hypothesized that the antioxidant transcription factor, Nrf2 (nuclear factor erythroid-derived 2 like 2), attenuates glioma cytotoxicity to Carmustine (BCNU), a widely used chemotherapeutic agent known to modulate cellular oxidative balance.

Methods

To test the hypothesis, we employed human malignant glioma cell line, U87MG and overexpression of Nrf2 in glioma cells was achieved using both pharmacological and genetic approaches.

Results

Notably, induction of Nrf2 was associated with increased expression of heme oxygenase-1 (HO-1), a stress inducible enzyme involved in anti-oxidant defense. In addition, over expression of Nrf2 in U87MG cells significantly attenuated the cytotoxicity of Carmustine as evidenced by both cellular viability assay and flow cytometry analysis. Consistent with this, antioxidants such as glutathione and N-acetyl cysteine significantly reduced Carmustine mediated glioma cytotoxicity.

Conclusions

Taken together, these data strongly implicate an unexplored role of Nrf2 in glioma resistance to Carmustine and raise the possible use of Nrf2 inhibitors as adjunct to Carmustine for the treatment of malignant glioma.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-015-1134-z) contains supplementary material, which is available to authorized users.

Genotoxic and cytostatic effects of 6-pentadecyl salicylic anacardic acid in transformed cell lines and peripheral blood mononuclear cells

In Mexico, as in many other countries, traditional medicine is used for the treatment of several diseases. In particular, Amphipterygium adstringens infusion is used for gastritis, gastric ulcers, and gastric cancer. Extracts from this tree have microbicidal effects against Helicobacter pylori, an important risk factor for gastric cancer development. Anacardic acids are constituents of A. adstringens, and 6-pentadecyl salicylic acid (6-PSA) is the most abundant. However, there is a lack of information regarding the effects of 6-PSA on cancer cells. Therefore, we investigated whether 6-PSA has differential effects on the induction of genotoxicity, cytostaticity, and apoptosis in normal human peripheral blood mononucleated cells (PBMCs), bone marrow polychromatic erythrocytes of Balb/c mice, and human transformed cell lines derived from both gastric cancer (AGS cells) and leukaemia (K562 cells). Treatment with 6-PSA (30-150 μM) reduced the viability of AGS and K562 cells together with a moderate, but significant, increase in the frequency of micronucleated cells and the induction of DNA breakage (Comet Assay). Moreover, 6-PSA increased the apoptosis rate in both the AGS and K562 cell lines in a caspase 8-dependent manner. In contrast, neither cytotoxicity nor genotoxicity were observed in PBMCs or bone marrow polychromatic erythrocytes of Balb/c mice after treatment with low doses of 6-PSA (0.2-2.0 mg/Kg). Instead, 6-PSA treatment resulted in the inhibition of PBMC proliferation, which was reversible after the compound was removed. Additionally, 6-PSA treatments (2-20 mg/Kg) increased the frequency of mature polychromatic erythrocytes in the bone marrow, suggesting a possible effect on the differentiation process of immune cells. The present results indicate that 6-PSA induces cytotoxicity and moderate genotoxicity, together with an increase in the apoptosis rate, in a caspase 8-dependent manner in gastric cancer cells. In contrast, a low toxicity was observed when PBMCs were exposed to 6-PSA.

Induction of the endoplasmic reticulum stress and autophagy in human lung carcinoma A549 cells by anacardic acid

Anacardic acid (AA, 2-hydroxy-6-pentadecylbenzoic acid), a constituent of the cashew-nut shell, has a variety of beneficial effects on the treatment of cancer and tumors. However, the fact that AA induces ER stress and autophagy in cancer cell is not known. We investigated the effect of AA on ER-stress and autophagy-induced cell death in cancer cells. Because of our interest in lung cancer, we used the non-small cell lung adenocarcinoma A549 cells treated with 3.0 μg/ml of AA for this research. In this research we found that AA induces intracellular Ca(2+) mobilization and ER stress. AA induced the ER stress-inducing factors, especially IRE1α, and the hallmarks of UPR, Grp78/Bip and GADD153/CHOP. AA inhibited the expression of p-PERK and its downstream substrate, p-elF2α. We also demonstrated that AA induces autophagy. Up-regulation of autophagy-related genes and the appearance of autophagosome in transfected cells with green fluorescent protein (GFP)-LC3 and GFP-Beclin1 plasmids showed the induction of autophagy in AA-treated A549 cells. The morphological analysis of intracellular organelles by TEM also showed the evidence that AA induces ER stress and autophagy. For the first time, our research showed that AA induces ER stress and autophagy in cancer cells.

Anacardic acid enhances the proliferation of human ovarian cancer cells

Background

Anacardic acid (AA) is a mixture of 2-hydroxy-6-alkylbenzoic acid homologs. Certain antitumor activities of AA have been reported in a variety of cancers. However, the function of AA in ovarian cancer, to date, has remained unknown.

Methods

Ovarian cancer cell lines were exposed to AA, after which cell proliferation, apoptosis, invasion and migration assays were performed. Phalloidin staining was used to observe lamellipodia formation. Reverse transcription polymerase chain reaction (RT-PCR) and western blotting were used to assess the mRNA and protein expression levels of Phosphatidylinositol 3-kinase (PI3K), vascular endothelial growth factor (VEGF) and caspase 3.

Results

Our results showed that AA promotes ovarian cancer cell proliferation, inhibits late apoptosis, and induces cell migration and invasion, as well as lamellipodia formation. AA exposure significantly up-regulated PI3K and VEGF mRNA and protein expression, while, in contrast, it down-regulated caspase 3 mRNA and protein expression in comparison to untreated control cells.

Conclusion

Taken together, our results demonstrate for the first time that AA may potentiate the proliferation, invasion, metastasis and lamellipodia formation in ovarian cancer cell lines via PI3K, VEGF and caspase 3 pathways.

Discovery of protein disulfide isomerase P5 inhibitors that reduce the secretion of MICA from cancer cells

In order to regulate the activity of P5, which is a member of the protein disulfide isomerase family, we screened a chemical compound library for P5-specific inhibitors, and identified two candidate compounds (anacardic acid and NSC74859). Interestingly, anacardic acid inhibited the reductase activity of P5, but did not inhibit the activity of protein disulfide isomerase (PDI), thiol-disulfide oxidoreductase ERp57, or thioredoxin. NSC74859 inhibited all these enzymes. When we examined the effects of these compounds on the secretion of soluble major histocompatibility complex class-I-related gene A (MICA) from cancer cells, anacardic acid was found to decrease secretion. In addition, anacardic acid was found to reduce the concentration of glutathione up-regulated by the anticancer drug 17-demethoxygeldanamycin in cancer cells. These results suggest that anacardic acid can both inhibit P5 reductase activity and decrease the secretion of soluble MICA from cancer cells. It might be a novel and potent anticancer treatment by targeting P5 on the surface of cancer cells.

Anacardic acid induces cell apoptosis associated with induction of ATF4-dependent endoplasmic reticulum stress

Anacardic acid (6-pentadecylsalicylic acid, AA), a natural compound isolated from the traditional medicine Amphipterygium adstringens, has been reported to possess antitumor activities. However, its molecular targets have not been thoroughly studied. Here, we report that AA is a potent inducer of endoplasmic reticulum (ER) stress, leading to apoptosis in hepatoma HepG2 and myeloma U266 cells. Induction of ER stress by AA was supported by a dose- and time-dependent increase in expression of the ER signaling downstream molecules, such as GRP78/BiP, phosphorylated eIF2α, ATF4 and CHOP in both HepG2 and U266 cell lines. Blockage of ATF4 expression by siRNA partially inhibited, while knockdown of CHOP expression by siRNA slightly increased AA-induced cell death in these cells. In addition, AA suppressed HepG2 xenograft tumor growth, associated with increased ER stress in vivo. These results suggest that AA induces tumor cell apoptosis associated with ATF4-dependent ER stress.

Anacardic acid (6-pentadecylsalicylic acid) induces apoptosis of prostate cancer cells through inhibition of androgen receptor and activation of p53 signaling

Anacardic acid (AA) is a mixture of 2-hydroxy-6-alkylbenzoic acid homologs. It is widely regarded as a non-specific histone acetyltransferase inhibitor of p300. The effects and the mechanisms of AA in LNCaP cells (prostate cancer cells) remain unknown. To investigate the effect of AA on LNCaP cells, we had carried out several experiments and found that AA inhibits LNCaP cell proliferation, induces G1/S cell cycle arrest and apoptosis of LNCaP cell. The mechanisms via which AA acts on LNCaP cells may be due to the following aspects. First, AA can regulate p300 transcription and protein level except for its mechanisms regulating function of p300 through post-translational modification in LNCaP cells. Second, AA can activate p53 through increasing the phosphorylation of p53 on Ser15 in LNCaP cells. AA can selectively activate p21 (target genes of p53). Third, AA can down-regulates androgen receptor (AR) through supressing p300. Our study suggests that AA has multiple anti-tumor activities in LNCaP cells and warrants further investigation.

Anacardic acid induces mitochondrial-mediated apoptosis in the A549 human lung adenocarcinoma cells

Anacardic acid (AA) is a constituent of the cashew nut shell and is known as an inhibitor of nuclear factor-κB (NF-κB). We investigated the cytotoxicity of AA on cancer cells and more experiments to reveal the cell death mechanism focused on A549 lung adenocarcinoma cells for our interest in lung cancer. To examine the molecular mechanism of cell death in AA treated A549 cells, we performed experiments such as transmission electron microscopy (TEM), western blot analysis, fluorescence-activated cell sorting (FACS), genomic DNA extraction and staining with 4',6-diamidino-2-phenylindole (DAPI). For the first time we revealed that AA induces caspase-independent apoptosis with no inhibition of cytotoxicity by pan-caspase inhibitor, Z-VAD-fmk, in A549 cells. Our results showed the possibility of mitochondrial-mediated apoptosis through the activation of apoptosis-inducing factor (AIF) and an intrinsic pathway executioner such as cytochrome c. This study will be helpful in revealing the cell death mechanisms and in developing potential drugs for lung cancer using AA.

Astrocyte-specific expression of survivin after intracerebral hemorrhage in mice: a possible role in reactive gliosis?

Intracerebral hemorrhage (ICH), the most common form of hemorrhagic stroke, accounts for up to 15% of all strokes. Despite maximal surgical intervention and supportive care, ICH is associated with significant morbidity and mortality, in part due to a lack of viable treatment options. Astrogliosis, a key feature of secondary injury that is characterized by glial proliferation, is a poorly-defined process that may produce both beneficial and detrimental outcomes after brain injury. Using a pre-clinical murine model of collagenase-induced ICH, we demonstrate a delayed upregulation of survivin, a key molecule involved in tumor cell proliferation and survival, by 72 h post-ICH. Notably, this increase in survivin expression was prominent in GFAP-positive astrocytes, but absent in neurons. Survivin was not expressed at detectable levels in the striatum of sham-operated mice. The expression of survivin after ICH was temporally and spatially associated with the expression of proliferating cell nuclear antigen (PCNA), an established marker of cellular proliferation. Moreover, the survivin expression was co-localized in proliferating astrocytes as evidenced by triple-label immunohistochemistry. Finally, shRNA-mediated silencing of survivin expression attenuated PCNA expression and reduced cellular proliferation in human glial cells. Together, these data suggest a potentially novel role for survivin in functionally promoting astrocytic proliferation after ICH.

Emerging roles of anacardic acid and its derivatives: a pharmacological overview

Anacardic acid (AA) is a bioactive phytochemical found in nutshell of Anacardium occidentale. Chemically, it is a mixture of several closely related organic compounds, each consisting of salicylic acid substituted with an alkyl chain. The traditional Ayurveda depicts nutshell oil as a medicinal remedy for alexeritic, amebicidal, gingivitis, malaria and syphilitic ulcers. However, the enduring research and emerging evidence suggests that AA could be a potent target molecule with bactericide, fungicide, insecticide, anti-termite and molluscicide properties and as a therapeutic agent in the treatment of the most serious pathophysiological disorders like cancer, oxidative damage, inflammation and obesity. Furthermore, AA was found to be a common inhibitor of several clinically targeted enzymes such as NFκB kinase, histone acetyltransferase (HATs), lipoxygenase (LOX-1), xanthine oxidase, tyrosinase and ureases. In view of this, we have made an effort to summarize the ongoing research on the therapeutical role of AA and its derivatives. The current MiniReview sheds light on the pharmacological applications, toxicity and allergic responses associated with AA and its derivatives. Although the available records are promising, much more detailed investigations into the therapeutical properties, particularly the anti-cancer and anti-inflammatory activities, are urgently needed. We hope the present MiniReview will attract and encourage further research on elucidating and appreciating the possible curative properties of AA and its derivatives in the management of multifactorial diseases.

CPTH6, a thiazole derivative, induces histone hypoacetylation and apoptosis in human leukemia cells

PURPOSE

We previously identified novel thiazole derivatives able to reduce histone acetylation and histone acetyltransferase (HAT) activity in yeast. Among these compounds, 3-methylcyclopentylidene-[4-(4'-chlorophenyl)thiazol-2-yl]hydrazone (CPTH6) has been selected and used throughout this study.

EXPERIMENTAL DESIGN

The effect of CPTH6 on histone acetylation, cell viability and differentiation, cell-cycle distribution, and apoptosis in a panel of acute myeloid leukemia and solid tumor cell lines has been evaluated.

RESULTS

Here, we showed that CPTH6 leads to an inhibition of Gcn5 and pCAF HAT activity. Moreover, it inhibits H3/H4 histones and α-tubulin acetylation of a panel of leukemia cell lines. Concentration- and time-dependent inhibition of cell viability, paralleled by accumulation of cells in the G(0)/G(1) phase and depletion from the S/G(2)M phases, was observed. The role of mitochondrial pathway on CPTH6-induced apoptosis was shown, being a decrease of mitochondrial membrane potential and the release of cytochrome c, from mitochondria to cytosol, induced by CPTH6. Also the involvement of Bcl-2 and Bcl-xL on CPTH6-induced apoptosis was found after overexpression of the two proteins in leukemia cells. Solid tumor cell lines from several origins were shown to be differently sensitive to CPTH6 treatment in terms of cell viability, and a correlation between the inhibitory efficacy on H3/H4 histones acetylation and cytotoxicity was found. Differentiating effect on leukemia and neuroblastoma cell lines was also induced by CPTH6.

CONCLUSIONS

These results make CPTH6 a suitable tool for discovery of molecular targets of HAT and, potentially, for the development of new anticancer therapies, which warrants further investigations.

Dietary phytochemicals, HDAC inhibition, and DNA damage/repair defects in cancer cells

Genomic instability is a common feature of cancer etiology. This provides an avenue for therapeutic intervention, since cancer cells are more susceptible than normal cells to DNA damaging agents. However, there is growing evidence that the epigenetic mechanisms that impact DNA methylation and histone status also contribute to genomic instability. The DNA damage response, for example, is modulated by the acetylation status of histone and non-histone proteins, and by the opposing activities of histone acetyltransferase and histone deacetylase (HDAC) enzymes. Many HDACs overexpressed in cancer cells have been implicated in protecting such cells from genotoxic insults. Thus, HDAC inhibitors, in addition to unsilencing tumor suppressor genes, also can silence DNA repair pathways, inactivate non-histone proteins that are required for DNA stability, and induce reactive oxygen species and DNA double-strand breaks. This review summarizes how dietary phytochemicals that affect the epigenome also can trigger DNA damage and repair mechanisms. Where such data is available, examples are cited from studies in vitro and in vivo of polyphenols, organosulfur/organoselenium compounds, indoles, sesquiterpene lactones, and miscellaneous agents such as anacardic acid. Finally, by virtue of their genetic and epigenetic mechanisms, cancer chemopreventive agents are being redefined as chemo- or radio-sensitizers. A sustained DNA damage response coupled with insufficient repair may be a pivotal mechanism for apoptosis induction in cancer cells exposed to dietary phytochemicals. Future research, including appropriate clinical investigation, should clarify these emerging concepts in the context of both genetic and epigenetic mechanisms dysregulated in cancer, and the pros and cons of specific dietary intervention strategies.