Betulinic acid reduces ultraviolet-C-induced DNA breakage in congenital melanocytic naeval cells: evidence for a potential role as a chemopreventive agent

Isolation, characterization and biological activities of betulin from Acacia nilotica bark

Medicinal plants are in use of humankind since ancient and still they are playing an important role in effective and safer natural drug delivery systems. Acacia nilotica (native of Egypt) commonly known as babul belongs to family Fabaceae, widely spread in India, Sri Lanka and Sudan. Being a common and important plant, using in many ways from fodder (shoots and leaves to animals) to dyeing (leather coloration) to medicine (root, bark, leaves, flower, gum, pods). The present study is focused on investigating the natural chemistry and important biological activities of the plant. Employing bioassay guided fractionation coupled with TLC and column chromatography, a pure fraction named AN-10 was isolated from ethyl acetate fraction of crude methanol extract which identified as "Betulin (Lupan-3ß,28-diol)" by Liebermann-Burchard test and structure elucidation by UV-Vis, NMR and MS techniques. A battery of in vitro biological assays for antioxidant, anti-inflammatory and anticancer were performed and betulin showed excellent potential in all assays. It was found that the inhibitory potential in all assays were dose dependent manner and after a range of concentration, the activities get leveled off with no further increase in activity.

Antitumor Activity of Betulinic Acid and Betulin in Canine Cancer Cell Lines

BACKGROUND/AIM

Betulinic acid (BA) and betulin (BT) exhibit a variety of pharmacological properties including anti-cancer, anti-inflammatory and anti-oxidant ones. Canine lymphoma and osteosarcoma have a high mortality rate and need more effective therapeutic approaches. In this study, the anti-proliferative and pro-apoptotic effects of BA and BT were investigated in canine T-cell lymphoma (CL-1), canine B-cell lymphoma (CLBL-1) and canine osteosarcoma (D-17) cell lines.

MATERIALS AND METHODS

The cultured cells were treated with several concentrations of BA or BT for 24, 48 and 72 h, and cell proliferation was assessed by the MTT assay. Cell apoptotic rate and cell cycle were analyzed using flow cytometry.

RESULTS

Anti-proliferative effect of BT and BA was concentration- and time-dependent. Moreover, BA and BT arrested cell cycle in S phase in CL-1 and D-17 cells, and in G₀/G₁ phase in CLBL-1 cells.

CONCLUSION

Both compounds showed an antitumor activity, and the effects of BA were stronger than that of BT.

The Search for Anticancer Agents from Tropical Plants

Many of the clinically used anticancer agents in Western medicine are derived from secondary metabolites found in terrestrial microbes, marine organisms, and higher plants, with additional compounds of this type being currently in clinical trials. If plants are taken specifically, it is generally agreed that the prospects of encountering enhanced small organic-molecule chemical diversity are better if tropical rather than temperate species are investigated in drug discovery efforts. Plant collection in tropical source countries requires considerable preparation and organization to conduct in a responsible manner that abides by the provisions of the 1992 Rio Convention of Biological Diversity and the 2010 Nagoya Protocol on Access to Genetic Resources. Correct taxonomic identifications and enhanced procedures for processing and documenting plant samples when collected in often difficult terrain are required. Phytochemical aspects of the work involve solvent fractionation, known compound dereplication, preliminary in vitro testing, and prioritization, leading to "activity-guided fractionation", compound structure determination, and analog development. Further evaluation of lead compounds requires solubility, formulation, preliminary pharmacokinetics, and in vivo testing in suitable models. Covering the work of the authors carried out in two sequential multidisciplinary, multi-institutional research projects, examples of very promising compounds discovered from plants acquired from Africa, Southeast Asia, the Americas, and the Caribbean region, and with potential anticancer activity will be mentioned. These include plant secondary metabolites of the diphyllin lignan, cyclopenta[b]benzofuran, triterpenoid, and tropane alkaloid types.

A convergent synthesis of novel alkyne-azide cycloaddition congeners of betulinic acid as potent cytotoxic agent

In an endeavour to develop potent anti-tumor agents from betulinic acid (BA), a series of C-28 derived 1,2,3-triazolyl derivatives were designed and synthesized by employing Cu(I) catalyzed Huisgen 1,3-dipolar cycloaddition reaction. All the derivatives were evaluated for cytotoxic activity by MTT assay against five different human cancer cell lines: lung (A549), colon (HCT116), prostate (PC3), pancreatic (MIA PaCa-2) and breast (T47D). The data revealed that compounds 11c, 11d, 11g, 11h and 13a possess most promising cytotoxic potential. The compound 11h was one of the most active compounds, with IC₅₀ values in the range of 4-6µM against all the five cancer cell lines. The results of this study suggested that derivatives with free -OH (11c, 11d and 11g) and free -COOH (11h and 13a) substitutions in the triazole moiety introduced at the C-28 position significantly improved the anti-tumor activity and may be the favourable position to synthesize potent anticancer leads from BA. Introduction of a non polar alkyl groups at C-28 position (10, 12 and 14) resulted in the significant loss of the activity. Further, DAPI staining, ROS generation and wound healing experiments revealed that compound 11h induces apoptosis in HCT-116 cells.

Botanicals With Dermatologic Properties Derived From First Nations Healing: Part 1—Trees

Introduction:

First Nations people have a long history of working with medicinal plants used to treat skin diseases. The purpose was to assess the dermatologic therapeutic potential of western red cedar, white spruce, birch, balsam poplar, and black spruce.

Methods:

Based on expert recommendations, 5 trees were selected that were used in First Nations medicine for cutaneous healing and have potential and/or current application to dermatology today. We searched several databases up to June 12, 2014.

Results:

Western red cedar’s known active principal compound, β-thujaplicin, has been studied in atopic dermatitis. White spruce’s known active principal compound, 7-hydroxymatairesinol, has anti-inflammatory activity, while phase II clinical trials have been completed on a birch bark emulsion for the treatment of actinic keratoses, epidermolysis bullosa, and the healing of split thickness graft donor sites. Balsam poplar has been used clinically as an anti-aging remedy. Black spruce bark contains higher amounts of the anti-oxidant trans-resveratrol than red wine.

Discussion:

North American traditional medicine has identified important botanical agents that are potentially relevant to both cosmetic and medical dermatology. This study is limited by the lack of good quality evidence contributing to the review. The article is limited to 5 trees, a fraction of those used by First Nations with dermatological properties.

Anticancer properties of ester derivatives of betulin in human metastatic melanoma cells (Me-45)

Background

Betulinic acid and betulin are triterpenes that have anticancer properties in various types of cancer. Unfortunately, the bioavailability and the bio-distribution of betulinic acid and its metabolic precursor, betulin are very low because of poor solubility in aqueous buffers.

Methods

In this study, we examined the anticancer properties of the ester derivatives of betulin compared to their precursors in a malignant melanoma cell line. We assessed five amino acid esters of betulin. The compounds contained four basic amino acids—natural lysine (l-Lys-OH) and three of its derivatives (l-Dap-OH, l-Dab-OH, and l-Orn-OH)—and alanine (l-Ala-OH) as a negative control (amino acid without an amine group in the side chain). The derivatives were more soluble than their precursors (betulin and betulinic acid) in water. The betulin esters were tested in the malignant melanoma cell line Me-45. To evaluate the cytotoxicity, MTT test was performed after 24, 48 and 72 h of incubation with the test compounds at a concentration range of 0.75–100 μM. For analysis of the apoptotic activity, TUNEL assay was performed. Additionally, expression of caspase-3 and PARP-1 was investigated immunocytochemically.

Results

The highest biological activity was observed with the lysine ester. The results showed that the highest cytotoxicity and the highest number of positively stained nuclei in metastatic melanoma Me-45 cells were obtained after 72 h of incubation with betulin derivatives containing lysine and ornithine.

Conclusions

The betulin ester derivatives showed enhanced antitumor activity compared to their non-modified precursors. Esters of betulin can be more potent anticancer agents than their precursor as a consequence of the rapid bioavailability and increased concentration in cancer cells.

A novel triazole derivative of betulinic acid induces extrinsic and intrinsic apoptosis in human leukemia HL-60 cells

In an attempt to arrive at more potent cytotoxic agent than the bioactive natural product betulinic acid, influence of small structural modifications of its 1, 2, 3 triazole derivatives tethered at C-28 and both C3, C-28 using click chemistry approach has been studied. The chemically characterized triazoles have been screened for in vitro cytotoxicity against four human cancer cell lines HL-60, MiaPaCa-2, PC-3 and A549 which has allowed to identify triazole derivative 28{1N (4-fluoro phenyl)-1H-1, 2, 3-triazol-4-yl} methyloxy betulinic ester having better potency profile than the parent compound with IC50 values in the range of 5-7 μM. It caused disruption of mitochondrial membrane potential, rendered Bcl-2 cleavage, Bax translocation and decrease Bcl-2/Bax ratio. These events are accompanied by activation of caspases -9, -3, which cleave the PARP-1. It also induces caspase-8, which is involved in extrinsic apoptotic pathway. Therefore, it induces apoptosis through both intrinsic and extrinsic pathways in human leukemia HL-60 cells.

New horizons for old drugs and drug leads

There is mounting urgency to find new drugs for the treatment of serious infectious diseases and cancer that are rapidly developing resistance to previously effective drugs. One approach to addressing this need is through drug repurposing, which refers to the discovery of new useful activities for "old" clinically used drugs through screening them against relevant disease targets. A large number of potential drug that, for various reasons, have failed to advance to clinical and commercial use can be added to the candidates available for such purposes. The application of new techniques and methodology developed through the impressive progress made in multidisciplinary, natural product-related research in recent years should aid substantially in expediting the discovery and development process. This review briefly outlines some of these developments as applied to a number of selected natural product examples, which may also include advances in chemical synthesis of derivatives with extended biological activities.

Betulinic Acid inhibits growth of cultured vascular smooth muscle cells in vitro by inducing g(1) arrest and apoptosis

Betulinic acid is a widely available plant-derived triterpene which is reported to possess selective cytotoxic activity against cancer cells of neuroectodermal origin and leukemia. However, the potential of betulinic acid as an antiproliferative and cytotoxic agent on vascular smooth muscle (VSMC) is still unclear. This study was carried out to demonstrate the antiproliferative and cytotoxic effect of betulinic acid on VSMCs using 3-[4,5-dimethylthizol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) assay, flow cytometry cell cycle assay, BrdU proliferation assay, acridine orange/propidium iodide staining, and comet assay. Result from MTT and BrdU assays indicated that betulinic acid was able to inhibit the growth and proliferation of VSMCs in a dose-dependent manner with IC₅₀ of 3.8 μg/mL significantly (P < 0.05). Nevertheless, betulinic acid exhibited G₁ cell cycle arrest in flow cytometry cell cycle profiling and low level of DNA damage against VSMC in acridine orange/propidium iodide and comet assay after 24 h of treatment. In conclusion, betulinic acid induced G₁ cell cycle arrest and dose-dependent DNA damage on VSMC.

Targeted inhibition of tumor proliferation, survival, and metastasis by pentacyclic triterpenoids: potential role in prevention and therapy of cancer

Over the last two decades, extensive research on plant-based medicinal compounds has revealed exciting and important pharmacological properties and activities of triterpenoids. Fruits, vegetables, cereals, pulses, herbs and medicinal plants are all considered to be biological sources of these triterpenoids, which have attracted great attention especially for their potent anti-inflammatory and anti-cancer activities. Published reports in the past have described the molecular mechanism(s) underlying the various biological activities of triterpenoids which range from inhibition of acute and chronic inflammation, inhibition of tumor cell proliferation, induction of apoptosis, suppression of angiogenesis and metastasis. However systematic analysis of various pharmacological properties of these important classes of compounds has not been done. In this review, we describe in detail the pre-clinical chemopreventive and therapeutic properties of selected triterpenoids that inhibit multiple intracellular signaling molecules and transcription factors involved in the initiation, progression and promotion of various cancers. Molecular targets modulated by these triterpenoids comprise, cytokines, chemokines, reactive oxygen intermediates, oncogenes, inflammatory enzymes such as COX-2, 5-LOX and MMPs, anti-apoptotic proteins, transcription factors such as NF-κB, STAT3, AP-1, CREB, and Nrf2 (nuclear factor erythroid 2-related factor) that regulate tumor cell proliferation, transformation, survival, invasion, angiogenesis, metastasis, chemoresistance and radioresistance. Finally, this review also analyzes the potential role of novel synthetic triterpenoids identified recently which mimic natural triterpenoids in physical and chemical properties and are moving rapidly from bench to bedside research.

New ionic derivatives of betulinic acid as highly potent anti-cancer agents

Betulinic acid is a natural compound with high in vitro cytotoxicity toward many cancer cells. However, the poor water solubility of this compound hampers an effective in vivo cancer study. We prepared new ionic derivatives of betulinic acid with higher water solubilities, without losing the structural integrity and functionality of this compound. As a result, these new ionic derivatives have shown much higher inhibitory effects against different cancer cell lines such as melanoma A375, neuroblastoma SH-SY5Y and breast adenocarcinoma MCF7. For A375 cell lines, the derivative 5 exhibited a low IC(50) value of 36 μM (vs 154 μM for betulinic acid); for MCF7 cell lines, the derivative 5 also exhibited a low IC(50) value of 25 μM (vs 112 μM for betulinic acid). The high cytotoxicity of these new derivatives can be linked to their greatly improved water solubility. Our assay method used little DMSO in aiding the dissolution of these derivatives to demonstrate the advantage of improved water solubility and to mimic the in vivo study conditions. The cell viability studies based on both MTT and LDH assay methods have confirmed the high inhibitory effect of our ionic derivatives of betulinic acid (particularly 4 and 5) against different cancer cells.

Mitochondria as therapeutic targets for the treatment of malignant disease

SIGNIFICANCE

Mitochondria exert vital functions during normal physiology and are also centrally involved in the regulation of various modes of cell death. Thus, engaging the mitochondrial apoptosis pathway presents an attractive possibility to activate lethal effectors in cancer cells.

RECENT ADVANCES

Compounds that directly target mitochondria offer the advantage to initiate mitochondrial outer membrane permeabilization independently of upstream signal transduction elements that are frequently impaired in human cancers. As a consequence, mitochondrion-targeted agents may bypass some forms of drug resistance.

CRITICAL ISSUES

An ever-increasing number of compounds, including natural compounds and rationally designed drugs, has been shown to directly act on mitochondria.

FUTURE DIRECTIONS

Forthcoming insights into the fine regulation of mitochondrial apoptosis will likely open future perspectives for cancer drug development.

Targeting mitochondria for cancer therapy

Mitochondria are the cells' powerhouse, but also their suicidal weapon store. Dozens of lethal signal transduction pathways converge on mitochondria to cause the permeabilization of the mitochondrial outer membrane, leading to the cytosolic release of pro-apoptotic proteins and to the impairment of the bioenergetic functions of mitochondria. The mitochondrial metabolism of cancer cells is deregulated owing to the use of glycolytic intermediates, which are normally destined for oxidative phosphorylation, in anabolic reactions. Activation of the cell death machinery in cancer cells by inhibiting tumour-specific alterations of the mitochondrial metabolism or by stimulating mitochondrial membrane permeabilization could therefore be promising therapeutic approaches.

Lupane triterpenoids--betulin and betulinic acid derivatives induce apoptosis in tumor cells

In the present investigation the antiproliferative activity of thirteen derivatives of betulinic acid and betulin was tested against five different tumor cell lines. The toxicity against normal human fibroblasts (WWO70327) and the mode of cell death on HT-29 (colon cancer) as well as caspase activity induced by the most active compounds, 9 (3-O-chloroacetylbetulinic acid) and 15 (28-O-chloroacetylbetulin) were determined. Investigated derivatives exerted a dose dependent antiproliferative action at micromolar concentrations toward target tumor cell lines. Treatment of HT-29 cells for 24 h with 9 and 15 induced apoptosis, as observed by dye exclusion test (trypan blue) and confirmed by the appearance of a typical ladder pattern in the DNA fragmentation assay.

Targeting mitochondrial apoptosis by betulinic acid in human cancers

Betulinic acid (BA) is a naturally occurring pentacyclic triterpene that exhibits a variety of biological activities including potent antitumor properties. This anticancer activity has been linked to its ability to directly trigger mitochondrial membrane permeabilization, a central event in the apoptotic process that seals the cell's fate. In contrast to the potent cytotoxicity of BA against a variety of cancer types, non-neoplastic cells as well as normal tissue remain relatively resistant to BA, thus pointing to a therapeutic window. Because agents that exert a direct action on mitochondria may bypass resistance to conventional chemotherapeutics, there is increasing interest to develop such compounds as experimental cancer therapeutics. Thus, mitochondrion-targeted agents such as BA hold great promise as a novel approach to overcome certain forms of drug resistance in human cancers.

Betulinic acid: a natural product with anticancer activity

Betulinic acid (BA) is a naturally occurring pentacyclic triterpene that exhibits a variety of biological activities including potent antitumor properties. This anticancer activity has been linked to its ability to directly trigger mitochondrial membrane permeabilization, a central event in the apoptotic process that seals the cell's fate. In contrast to the potent cytotoxicity of BA against a variety of cancer types, nonmalignant cells and normal tissue remained relatively resistant to BA, indicating a therapeutic window. Since agents that exert a direct action on mitochondria may trigger cell death under circumstances in which standard chemotherapeutics fail, there is increasing interest to develop such compounds as experimental cancer therapeutics. Thus, mitochondrion-targeted agents such as BA hold great promise as a novel approach to bypass certain forms of drug resistance in human cancers.

Betulinic Acid for cancer treatment and prevention

Betulinic acid is a natural product with a range of biological effects, for example potent antitumor activity. This anticancer property is linked to its ability to induce apoptotic cell death in cancer cells by triggering the mitochondrial pathway of apoptosis. In contrast to the cytotoxicity of betulinic acid against a variety of cancer types, normal cells and tissue are relatively resistant to betulinic acid, pointing to a therapeutic window. Compounds that exert a direct action on mitochondria present promising experimental cancer therapeutics, since they may trigger cell death under circumstances in which standard chemotherapeutics fail. Thus, mitochondrion-targeted agents such as betulinic acid hold great promise as a novel therapeutic strategy in the treatment of human cancers.

Protection of betulin against cadmium-induced apoptosis in hepatoma cells

The protective effects of betulin (BT) against cadmium (Cd)-induced cytotoxicity have been previously reported. However, the mechanisms responsible for these protective effects are unclear. Therefore, this study investigated the mechanisms responsible for the protection of BT against Cd-induced cytotoxicity in human hepatoma cell lines. The protection of BT against Cd cytotoxicity was more effective in the HepG2 than in the Hep3B cells. The protection of BT on Cd-induced cytotoxicity in the HepG2 cells appeared to be related to the inhibition of apoptosis, as determined by PI staining and DNA fragmentation analysis. The anti-apoptosis exerted by BT involved the blocking of Cd-induced reactive oxygen species (ROS) generation, the abrogation of the Cd-induced Fas upregulation, the blocking of caspase-8-dependent Bid activation, and subsequent inhibition of mitochondrial pathway. The BT pretreatment did not affect the p21 and p53 expression levels, when compared with those of the treated cells with Cd alone. BT induced the transient S phase arrest at an early stage and the G0/G1 arrest at a relatively late stage, but it did not observe the sub-G1 apoptotic peak. In the Hep3B cells, Cd did not induce ROS generation. The BT pretreatment partially inhibited the Cd-induced apoptosis, which was related with the incomplete blockage in caspase-9 or -3 activation, as well as in Bax activation. Taken together, it was found that Cd can induce apoptosis via the Fas-dependent and -independent apoptosis pathways. However, the observed protective effects of BT were clearly more sensitive to Fas-expressing HepG2 cells than to Fas-deficient Hep3B cells.

Betulinic acid induces apoptosis in skin cancer cells and differentiation in normal human keratinocytes

Betulinic acid (BA), a pentacyclic triterpene of plant origin, induces cell death in melanoma cells and other malignant cells of neuroectodermal origin. Little is known about additional biological effects in normal target cells. We show, in this study, that BA induces differentiation as well as cell death in normal human keratinocytes (NHK). Cytotoxicity profiles of BA are compared among normal human keratinocytes, HaCaT cells, IGR1 melanoma cells and normal melanocytes. As expected, BA is toxic to all cell types, normal and malignant, but varies in its cytotoxic potency and in the extent of induction of apoptotic vs. necrotic cell death in the four different skin cell types. Apoptosis is proved by annexin V and Apo2.7 binding and by DNA fragmentation. Induction of differentiation-associated antigens in keratinocytes--filaggrin and involucrin--is demonstrated, together with specific morphological changes in treated cell cultures. BA, apart from its cytotoxic activities in cellular systems, is capable of inducing differentiation of NHK into corneocytes without immediately provoking apoptotic cell death.

Effect of Betula bark extract on spontaneous and induced mutagenesis in mice

Study was performed by counting cells with chromosomal aberrations in C57Bl/6 mice. Bark dry extract was given perorally in doses of 50, 150, 450, and 1500 mg/kg. Mutagens dioxidine and cyclophosphamide were injected intraperitoneally in doses of 200 and 20 mg/kg, respectively. Bark dry extract in doses of 150 and 1500 mg/kg did not possess cytogenetic activity. Bark dry extract in doses of 50, 150, and 450 mg/kg significantly decreased the cytogenetic effect of mutagens under various regimens of treatment with the preparation (single combined administration, 5-day pretreatment, and 5-day combined administration). Our results indicate that bark dry extract possesses antimutagenic properties.

Immobilized betulinic acid column and its interactions with phospholipase A2 and snake venom proteins

Betulinic acid (BA) is a plant-derived pentacyclic triterpenoid. Although BA has been found to have diverse pharmacological effects, including anti-tumor and anti-inflammatory actions and potential as inhibitor of phospholipase A2 (PLA2), its cellular targets remain unclear. In this study, BA was immobilized onto an acrylamide matrix. The immobilized-BA column could retain the purified PLA2 of bovine pancreas or the PLA2 of snake venom from Naja nigricollis. The bound PLA2 were not eluted by high salt concentrations but were eluted by either acid or calcium free buffer. Besides the PLA2, a group of basic proteins of snake venom with molecular weights of about 7 kDa were also strongly bound by immobilized BA. One of these proteins was identified as gamma-cardiotoxin. The usefulness of immobilized BA for exploring the cellular targets of BA is discussed.

Chemistry, biological activity, and chemotherapeutic potential of betulinic acid for the prevention and treatment of cancer and HIV infection

3beta-Hydroxy-lup-20(29)-en-28-oic acid (betulinic acid) is a pentacyclic lupane-type triterpene that is widely distributed throughout the plant kingdom. A variety of biological activities have been ascribed to betulinic acid including anti-inflammatory and in vitro antimalarial effects. However, betulinic acid is most highly regarded for its anti-HIV-1 activity and specific cytotoxicity against a variety of tumor cell lines. Interest in developing even more potent anti-HIV agents based on betulinic acid has led to the discovery of a host of highly active derivatives exhibiting greater potencies and better therapeutic indices than some current clinical anti-HIV agents. While its mechanism of action has not been fully determined, it has been shown that some betulinic acid analogs disrupt viral fusion to the cell in a post-binding step through interaction with the viral glycoprotein gp41 whereas others disrupt assembly and budding of the HIV-1 virus. With regard to its anticancer properties, betulinic acid was previously reported to exhibit selective cytotoxicity against several melanoma-derived cell lines. However, more recent work has demonstrated that betulinic acid is cytotoxic against other non-melanoma (neuroectodermal and malignant brain tumor) human tumor varieties. Betulinic acid appears to function by means of inducing apoptosis in cells irrespective of their p53 status. Because of its selective cytotoxicity against tumor cells and favorable therapeutic index, even at doses up to 500 mg/kg body weight, betulinic acid is a very promising new chemotherapeutic agent for the treatment of HIV infection and cancer.

Betulinic acid suppresses carcinogen-induced NF-kappa B activation through inhibition of I kappa B alpha kinase and p65 phosphorylation: abrogation of cyclooxygenase-2 and matrix metalloprotease-9

Betulinic acid (BA), a pentacyclic triterpene isolated from the bark of the white birch tree, has been reported to be a selective inducer of apoptosis in tumor cells. It also exhibits anti-inflammatory and immunomodulatory properties. How BA mediates these effects is not known. Because of the critical role of the transcription factor NF-kappaB in growth modulatory, inflammatory, and immune responses, we postulated that BA modulates the activity of this factor. In this study we investigated the effect of BA on NF-kappaB and NF-kappaB-regulated gene expression activated by a variety of inflammatory and carcinogenic agents. BA suppressed NF-kappaB activation induced by TNF, PMA, cigarette smoke, okadaic acid, IL-1, and H(2)O(2). The suppression of NF-kappaB activation was not cell-type specific. BA suppressed the activation of IkappaBalpha kinase, thus abrogating the phosphorylation and degradation of IkappaBalpha. We found that BA inhibited NF-kappaB activated by TNFR 1, TNFR-associated death domain, TNFR-associated factor 2, NF-kappaB-inducing kinase, and IkappaBalpha kinase. Treatment of cells with this triterpinoid also suppressed NF-kappaB-dependent reporter gene expression and the production of NF-kappaB-regulated gene products such as cyclooxygenase-2 and matrix metaloproteinase-9 induced by inflammatory stimuli. Furthermore, BA enhanced TNF-induced apoptosis. Overall, our results indicated that BA inhibits activation of NF-kappaB and NF-kappaB-regulated gene expression induced by carcinogens and inflammatory stimuli. This may provide a molecular basis for the ability of BA to mediate apoptosis, suppress inflammation, and modulate the immune response.

Melanoma cells can tolerate high levels of transcriptionally active endogenous p53 but are sensitive to retrovirus-transduced p53

Malignant melanomas are frequently characterized by elevated levels of wild-type p53, suggesting that p53 function could be suppressed by a mechanism different from p53 mutation. We analysed the functionality of the p53-signaling pathway in a panel of seven human melanoma cell lines consisting of one p53-deficient line, two lines with mutant p53, and four lines expressing wild-type p53. Only lines with wild-type p53 were characterized by elevated levels of endogenous p21, high activity of p53-responsive reporters and accumulation of p53 in response to genotoxic stress, common properties of functional p53. The presence of wild-type p53 was associated with depletion or loss of p14ARF and p16 expression. The levels of p33ING1b and p24ING1c, two major products of Ing1 locus and putative coregulators of p53, were elevated in all cell lines tested; however, ectopic expression of either ING1 isoform had no effect on cell proliferation. All lines retained expression of Apaf-1, and all but one remained sensitive to ectopic expression of retrovirus-transduced p53. Our data indicate that regardless of abnormally high levels of p53 in melanomas, their p53 remains competent in transactivation of its targets, and, if highly overexpressed, capable of growth inhibition. Hence, the p53 pathway in malignant melanomas can be considered for pharmacological targeting and anticancer gene therapy.

Congenital melanocytic nevi. Evaluation and management

This article discusses the care of patients with CMN, who often require a multidisciplinary approach involving pediatricians, family physicians, internists, dermatologists, psychologists, plastic surgeons, neurologists, and radiologists. The cosmetic and psychosocial issues, combined with the knowledge of the increased risk of developing melanoma or NCM, is a huge burden that many of these patients and their families have to carry. This article describes the importance for physicians to help these patients and families come to terms with these issues, as well as remind their patients and their family members that although melanoma, NCM, or other complications can develop, most affected individuals do not develop any complications. The article mentions that there are many healthy, happy, functional adults with large, small, and multiple CMN alive today.