Magnolol, a natural compound, induces apoptosis of SGC-7901 human gastric adenocarcinoma cells via the mitochondrial and PI3K/Akt signaling pathways

Altholactone Inhibits NF-κB and STAT3 Activation and Induces Reactive Oxygen Species-Mediated Apoptosis in Prostate Cancer DU145 Cells

Altholactone, a natural compound isolated from Goniothalamus spp., has demonstrated anti-inflammatory and anticancer activities, but its molecular mechanisms are still not fully defined. Nuclear factor kappa B (NF-κB) and signal transducer and activator of transcription 3 (STAT3) play pivotal roles in the cell survival of many human tumors. The objective of this study was to elucidate the mechanism of action of altholactone against prostate cancer DU145 cells and to evaluate whether its effects are mediated by inhibition of NF-κB and STAT3 activity. Altholactone inhibited proliferation of DU145 cells and induced cell cycle arrest in S phase and triggered apoptosis. Reporter assays revealed that altholactone repressed p65- and TNF-α-enhanced NF-κB transcriptional activity and also inhibited both constitutive and IL-6-induced transcriptional activity of STAT3. Consistent with this, altholactone down-regulated phosphorylation of STAT3 and moreover, decreased constitutively active mutant of STAT3 (STAT3C)-induced transcriptional activity. Altholactone treatment also results in down-regulation of STAT3 target genes such as survivin, and Bcl-2 followed by up regulation of pro-apoptotic Bax protein. However, pre-treatment with the antioxidant N-acetylcysteine (NAC) significantly inhibited the activation of Bax and prevented down-regulation of STAT3 target genes. Collectively, our findings suggest that altholactone induces DU145 cells death through inhibition of NF-κB and STAT3 activity.

Preventive effect of Actinidia valvata Dunn extract on N-methyl-N'-nitro-N-nitrosoguanidine-induced gastrointestinal cancer in rats

PURPOSE

This study was conducted to assess the preventive effect of Actinidia valvata Dunn (AVD) extract on an animal model of gastrointestinal carcinogenesis on the basis of changes in tumor incidence, cell proliferation, and apoptosis.

MATERIALS AND METHODS

Seventy-five male Wistar rats were divided into five different treatment groups with 15 rats in each group. Group I was given normal feed, whereas Groups II to IV were treated with 10% sodium chloride in the first six weeks and 100 ug/mL of N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) in drinking water for 24 weeks. Group II was then given normal feed, whereas Group III was given AVD extract (0.24 g/kg/day) for 12 weeks. Group IV was given AVD extract from the first week to the 36th week, whereas Group V was treated with AVD extract alone for 36 weeks. All rats were sacrificed at the end of the 36-week experiment and assessed for the presence of gastrointestinal tumors. The occurrence of cancer was evaluated by histology. Bax, Bcl-2, Caspase-3, and cyclinD1 were determined by immunohistochemical staining and Western blotting.

RESULTS

The incidences of gastric cancer were 0% in Group I, 73.3% in Group II, 33.3% in Group III, 26.7% in Group IV, and 0% in Group V. Bcl-2 and cyclinD1 expression was decreased in AVD extract treated groups, whereas Bax and Caspase-3 expression was increased. Comparison with group II revealed significant differences (p<0.01).

CONCLUSIONS

AVD extract exhibits an obvious preventive effect on gastrointestinal carcinogenesis induced by MNNG in rats through the regulation of cell proliferation and apoptosis.

Antitumor effects and the underlying mechanism of licochalcone A combined with 5-fluorouracil in gastric cancer cells

Licochalcone A (LCA) is a flavonoid extracted from licorice root that has antiparasitic, antibacterial and antitumor properties. Previous studies have revealed that LCA may be a novel treatment for gastric cancer. The present study further assessed the potential antitumor effects of LCA alone or in combination with 5-fluorouracil (5-FU), and the underlying mechanisms responsible for those effects in gastric cancer cells. The effects of LCA alone or in combination with 5-FU on SGC7901 and MKN-45 gastric cancer cell lines were studied using Cell Counting Kit-8, cell cycle, apoptosis and western blot analyses of cell check points and apoptosis-associated proteins. The results revealed that LCA inhibited cell proliferation, blocked cell cycle progression at the G₂/M transition and induced apoptosis. Western blot analysis demonstrated that LCA treatment increased the levels of tumor proteins 21 and 27, as well as mouse double minute 2 homolog in gastric cancer cells. In addition, LCA treatment increased the expression levels of Bax, cleaved-poly ADP ribose polymerase, tumor protein 53 and caspase 3, and decreased the expression levels of Bcl-2. Therefore, the present study demonstrated that LCA alone or in combination with 5-FU may have significant anticancer effects on gastric cancer cells, and may be a novel therapeutic for the treatment of gastric cancer in the future.

Natural products against cancer angiogenesis

The process of angiogenesis is quite well-known nowadays. Some medicines and extracts affecting this process are already used routinely in supporting the conventional treatment of many diseases that are considered angiogenic such as cancer. However, we must be aware that the area of currently used drugs of this type is much narrower than the theoretical possibilities existing in therapeutic angiogenesis. Plant substances are a large and diverse group of compounds that are found naturally in fruits, vegetables, spices, and medicinal plants. They also have different anticancer properties. The aim of this literature review article is to present the current state of knowledge concerning the molecular targets of tumor angiogenesis and the active substances (polyphenols, alkaloids, phytohormones, carbohydrates, and terpenes) derived from natural sources, whose activity against cancer angiogenesis has been confirmed.

Cytotoxicity of withasteroids: withametelin induces cell cycle arrest at G2/M phase and mitochondria-mediated apoptosis in non-small cell lung cancer A549 cells

Considerable interest has been gained by withasteroids because of their structural uniqueness and wide spectrum of biological activities. However, limited systematic studies for proving their cytotoxic potential have so far been reported. Hence, an attempt was made to test the cytotoxicity of six withasteroids viz., withametelin (WM), withaphysalin D, withaphysalin E, 12-deoxywithastramonolide, Withaperuvin B, and physalolactone against A549, HT-29, and MDA-MB-231 cancer cell lines. Significant cytotoxic effect of WM against A549 cells (IC₅₀ value of 6.0 μM), MDA-MB-231 cells (IC₅₀ value of 7.6 μM), and HT-29 cells (IC₅₀ value of 8.2 μM) was observed. Withaperuvin B and physalolactone were found to be effective against MDA-MB-231 cells. The significantly active WM arrested the A549 cells at G2/M phase and downregulated the expression of G2/M regulatory proteins such as cdc2, cyclin B1, and cdc25C. Apoptosis induced by WM in A549 cells was associated with the generation of ROS and depletion of MMP. Furthermore, WM treatment resulted in Bax upregulation, Bcl-2 downregulation, translocation of cytochrome c to mitochondria, activation of caspase-9 and -3, and PARP cleavage corroborating the apoptosis induction through intrinsic apoptotic pathway. Thus, WM possessing broader cytotoxic effect is a promising lead molecule which has the potential to be developed as a new therapeutic agent for NSCLC.

3-Bromopyruvate inhibits cell proliferation and induces apoptosis in CD133+ population in human glioma

The study was aimed to investigate the role of 3-bromopyruvate in inhibition of CD133+ U87 human glioma cell population growth. The results demonstrated that 3-bromopyruvate inhibited the viability of both CD133+ and parental cells derived from U87 human glioma cell line. However, the 3-bromopyruvate-induced inhibition in viability was more prominent in CD133+ cells at 10 μM concentration after 48 h. Treatment of CD133+ cells with 3-bromopyruvate caused reduction in cell population and cell size, membrane bubbling, and degradation of cell membranes. Hoechst 33258 staining showed condensation of chromatin material and fragmentation of DNA in treated CD133+ cells after 48 h. 3-Bromopyruvate inhibited the migration rate of CD133+ cells significantly compared to the parental cells. Flow cytometry revealed that exposure of CD133+ cells to 3-bromopyruvate increased the cell population in S phase from 24.5 to 37.9 % with increase in time from 12 to 48 h. In addition, 3-bromopyruvate significantly enhanced the expression of Bax and cleaved caspase 3 in CD133+ cells compared to the parental cells. Therefore, 3-bromopyruvate is a potent chemotherapeutic agent for the treatment of glioma by targeting stem cells selectively.

Magnolol inhibits growth of gallbladder cancer cells through the p53 pathway

Magnolol, the major active compound found in Magnolia officinalis has a wide range of clinical applications due to its anti-inflammation and anti-oxidation effects. This study investigated the effects of magnolol on the growth of human gallbladder carcinoma (GBC) cell lines. The results indicated that magnolol could significantly inhibit the growth of GBC cell lines in a dose- and time-dependent manner. Magnolol also blocked cell cycle progression at G0 /G1 phase and induced mitochondrial-related apoptosis by upregulating p53 and p21 protein levels and by downregulating cyclin D1, CDC25A, and Cdk2 protein levels. When cells were pretreated with a p53 inhibitor (pifithrin-a), followed by magnolol treatment, pifithrin-a blocked magnolol-induced apoptosis and G0 /G1 arrest. In vivo, magnolol suppressed tumor growth and activated the same mechanisms as were activated in vitro. In conclusion, our study is the first to report that magnolol has an inhibitory effect on the growth of GBC cells and that this compound may have potential as a novel therapeutic agent for the treatment of GBC.

Design, synthesis, and anticancer evaluation of long-chain alkoxylated mono-carbonyl analogues of curcumin

Curcumin is a nontoxic phenolic compound that modulates the activity of several cellular targets that have been linked with cancers and other chronic diseases. However, the efficacy of curcumin in the clinic has been limited by its poor bioavailability and rapid metabolism in vivo. We have previously reported the design and discovery of series of 5-carbon linker-containing mono-carbonyl analogues of curcumin (MACs) as anti-cancer agents. In continuation of our ongoing research, we designed and synthesized 37 novel long-chain alkoxylated MACs for anti-cancer evaluation here. The MTS assay was used to determine the cytotoxicity of compounds in gastrointestinal cancer cells. Compounds 5, 28, and 29 showed strongest inhibition against gastric cancer cell proliferation and were subjected to further analysis. The effects of 5, 28, and 29 on cell apoptosis were measured by flow cytometry. Expression levels of Bcl-2, cleaved poly ADP-ribose polymerase (PARP), and pro-caspase-3 were detected by western blotting. Compounds 5, 28, and 29 induced apoptosis in human gastric carcinoma cells, increased PARP cleavage, and decreased expression of Bcl-2 and pro-caspase-3 protein. We then showed that compound 28, which possessed the strongest activity among the test compounds in vitro, exhibited significant tumor inhibition in SGC7901-driven xenograft mouse model. Taken together, the novel compound 28 could be further explored as an effective anticancer agent for the treatment of human gastric cancer.

Cbl participates in shikonin-induced apoptosis by negatively regulating phosphoinositide 3-kinase/protein kinase B signaling

Shikonin, a naturally occurring naphthoquinone, exhibits anti-tumorigenic activity. However, its precise mechanisms of action have remained elusive. In the present study, the involvement in the action of shikonin of the ubiquitin ligases Cbl-b and c-Cbl, which are negative regulators of phosphoinositide 3-kinase (PI3K) activation, was investigated. Shikonin was observed to reduce cell viability and induce apoptosis and G2/M phase arrest in lung cancer cells. In addition, shikonin increased the protein levels of B-cell lymphoma 2 (Bcl-2)-associated X and p53 and reduced those of Bcl-2. Additionally, shikonin inhibited PI3k/Akt activity and upregulated Cbl protein expression. In addition, a specific inhibitor of PI3K, LY294002, was observed to have a synergistic effect on the proliferation inhibition and apoptotic induction of A549 cells with shikonin. In conclusion, the results of the present study suggested that Cbl proteins promote shikonin-induced apoptosis by negatively regulating PI3K/Akt signaling in lung cancer cells.

Elaborating the role of natural products-induced autophagy in cancer treatment: achievements and artifacts in the state of the art

Autophagy is a homeostatic process that is highly conserved across different types of mammalian cells. Autophagy is able to relieve tumor cell from nutrient and oxidative stress during the rapid expansion of cancer. Excessive and sustained autophagy may lead to cell death and tumor shrinkage. It was shown in literature that many anticancer natural compounds and extracts could initiate autophagy in tumor cells. As summarized in this review, the tumor suppressive action of natural products-induced autophagy may lead to cell senescence, provoke apoptosis-independent cell death, and complement apoptotic cell death by robust or target-specific mechanisms. In some cases, natural products-induced autophagy could protect tumor cells from apoptotic death. Technical variations in detecting autophagy affect data quality, and study focus should be made on elaborating the role of autophagy in deciding cell fate. In vivo study monitoring of autophagy in cancer treatment is expected to be the future direction. The clinical-relevant action of autophagy-inducing natural products should be highlighted in future study. As natural products are an important resource in discovery of lead compound of anticancer drug, study on the role of autophagy in tumor suppressive effect of natural products continues to be necessary and emerging.

Anticancer effects of crocetin in human esophageal squamous cell carcinoma KYSE-150 cells

Crocetin is the main pharmacologically-active component of saffron and has been considered as a promising candidate for cancer chemoprevention. The purpose of the present study was to investigate the anticancer effects of crocetin and the possible mechanisms of these properties in the esophageal squamous cell carcinoma cell line KYSE-150. The KYSE-150 cells were cultured in Dulbecco’s modified Eagle’s medium and incubated with 0, 12.5, 25, 50, 100 or 200 μmol/l crocetin for 48 h. Cell proliferation was measured using an MTT assay. Hoechst 33258 staining and observation under fluorescent microscopy were used to analyze the proapoptotic effects of crocetin. The migration rate was assessed by a wound-healing assay. The cell cycle distribution was analyzed using flow cytometry analysis subsequent to propidium iodide staining. The expression of B-cell lymphoma-2-associated X protein (Bax) and cleaved caspase 3 was determined by western blot analysis. It was found that treatment of KYSE-150 cells with crocetin for 48 h significantly inhibited the proliferation of the cells in a concentration-dependent manner, and the inhibition of proliferation was associated with S phase arrest. Crocetin was also found to induce morphological changes and cell apoptosis in a dose-dependent manner through increased expression of proapoptotic Bax and activated caspase 3. In addition, crocetin suppressed the migration of KYSE-150 cells. The present study provides evidence that crocetin exerts a prominent chemopreventive effect against esophageal cancer through the inhibition of cell proliferation, migration and induction of apoptosis. These findings reveal that crocetin may be considered to be a promising future chemotherapeutic agent for esophageal cancer therapy.

Magnolol causes alterations in the cell cycle in androgen insensitive human prostate cancer cells in vitro by affecting expression of key cell cycle regulatory proteins

Prostate cancer, one of the most common cancers in the Western world, affects many men worldwide. This study investigated the effects of magnolol, a compound found in the roots and bark of the magnolia tree Magnolia officinalis, on the behavior of 2 androgen insensitive human prostate cancer cell lines, DU145 and PC3, in vitro. Magnolol, in a 24-h exposure at 40 and 80 μM, was found to be cytotoxic to cells. Magnolol also affected cell cycle progression of DU145 and PC3 cells, resulting in alterations to the cell cycle and subsequently decreasing the proportion of cells entering the G2/M-phase of the cell cycle. Magnolol inhibited the expression of cell cycle regulatory proteins including cyclins A, B1, D1, and E, as well as CDK2 and CDK4. Protein expression levels of pRBp107 decreased and pRBp130 protein expression levels increased in response to magnolol exposure, whereas p16(INK4a), p21, and p27 protein expression levels were apparently unchanged post 24-h exposure. Magnolol exposure at 6 h did increase p27 protein expression levels. This study has demonstrated that magnolol can alter the behavior of androgen insensitive human prostate cancer cells in vitro and suggests that magnolol may have potential as a novel anti-prostate cancer agent.

Identification of Hirsutine as an anti-metastatic phytochemical by targeting NF-κB activation

Nuclear factor-κB (NF-κB) activation has been implicated not only in carcinogenesis but also in cancer cell invasion and metastatic process; therefore, targeting the NF-κB pathway is an attractive strategy for controlling meta-stasis. Amongst 56 chemically defined compounds derived from natural products, we have identified a new phytochemical compound Hirsutine, which strongly suppresses NF-κB activity in murine 4T1 breast cancer cells. In accordance with the NF-κB inhibition, Hirsutine reduced the metastatic potential of 4T1 cells, as seen in the inhibition of the migration and invasion capacity of 4T1 cells. Hirsutine further inhibited the constitutive expression of MMP-2 and MMP-9 in 4T1 cells, and reduced the in vivo lung metastatic potential of 4T1 cells in the experimental model. Given that the migration of human breast cancer cells was also inhibited, our present study implies that Hirsutine is an attractive phytochemical compound for reducing metastasis potential of cancer cells by regulating tumor-promoting NF-κB activity.

Targeting apoptosis pathways in cancer and perspectives with natural compounds from mother nature

Although the incidences are increasing day after day, scientists and researchers taken individually or by research group are trying to fight against cancer by several ways and also by different approaches and techniques. Sesquiterpenes, flavonoids, alkaloids, diterpenoids, and polyphenolic represent a large and diverse group of naturally occurring compounds found in a variety of fruits, vegetables, and medicinal plants with various anticancer properties. In this review, our aim is to give our perspective on the current status of the natural compounds belonging to these groups and discuss their natural sources, their anticancer activity, their molecular targets, and their mechanism of actions with specific emphasis on apoptosis pathways, which may help the further design and conduct of preclinical and clinical trials. Unlike pharmaceutical drugs, the selected natural compounds induce apoptosis by targeting multiple cellular signaling pathways including transcription factors, growth factors, tumor cell survival factors, inflammatory cytokines, protein kinases, and angiogenesis that are frequently deregulated in cancers and suggest that their simultaneous targeting by these compounds could result in efficacious and selective killing of cancer cells. This review suggests that they provide a novel opportunity for treatment of cancer, but clinical trials are still required to further validate them in cancer chemotherapy.

Crocetin induces apoptosis of BGC-823 human gastric cancer cells

Gastric cancer (GC) is one of the most common types of gastrointestinal tumors worldwide, and the side effects of chemotherapeutic drugs and the resistance to chemotherapy remain problematic in its clinical treatment. Therefore, safe and effective novel agents are urgently required. The purpose of the present study was to investigate the crocetin‑sensitive treatment of GC and its possible mechanisms. BGC‑823 human GC cells were treated with crocetin. The effects of crocetin on the viability of the cells were determined by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Hoechst 33258 dyeing and Rh123 staining were used to detect cell apoptosis. The BGC‑823 cells were subjected to western blotting analysis for detection of cytochrome c and cleaved caspase‑3 protein expression. Crocetin inhibited the proliferation of the GC cell line in a dose‑ and time‑dependent manner. Apoptotic BGC‑823 cells induced by crocetin were stained by Hoechst 33258 and observed under a light microscope for cell membrane staining of dense nuclei, nuclear pyknosis, fragmentation, chromatin condensation and highlighted nuclear membrane staining. This revealed a decline in the mitochondrial membrane potential of the BGC‑823 cells. Crocetin also induced caspase‑3 activation and cytochrome c translocation into the cytosol from the mitochondria. The results of this study indicate that crocetin induces the apoptosis of BGC‑823 cells, and may be used as an effective agent in the treatment of GC.

Autophagy triggered by magnolol derivative negatively regulates angiogenesis

Angiogenesis has a key role in the tumor progression and metastasis; targeting endothelial cell proliferation has emerged as a promising therapeutic strategy for the prevention of cancer. Previous studies have revealed a complex association between the process of angiogenesis and autophagy and its outcome on tumorigenesis. Autophagy, also known as type-II cell death, has been identified as an alternative way of cell killing in apoptotic-resistant cancer cells. However, its involvement in chemoresistance and tumor promotion is also well known. In this study, we used a derivate of natural product magnolol (Ery5), a potent autophagy inducer, to study the association between the autophagy and angiogenesis in both in vitro and in vivo model system. We found that the robust autophagy triggered by Ery5, inhibited angiogenesis and caused cell death independent of the apoptosis in human umbilical cord vein endothelial cells and PC-3 cells. Ery5 induced autophagy effectively inhibited cell proliferation, migration, invasion and tube formation. We further demonstrated that Ery5-mediated autophagy and subsequent inhibition of angiogenesis was reversed when autophagy was inhibited through 3-methyl adenine and knocking down of key autophagy proteins ATG7 and microtubule-associated protein light chain 3. While evaluating the negative regulation of autophagy on angiogenesis, it was interesting to find that angiogenic environment produced by the treatment of VEGF and CoCl2 remarkably downregulated the autophagy and autophagic cell death induced by Ery5. These studies, while disclosing the vital role of autophagy in the regulation of angiogenesis, also suggest that the potent modulators of autophagy can lead to the development of effective therapeutics in apoptosis-resistant cancer.

Targeting apoptosis pathways in cancer with alantolactone and isoalantolactone

Alantolactone and isoalantolactone, main bioactive compounds that are present in many medicinal plants such as Inula helenium, L. Inula japonica, Aucklandia lappa, Inula racemosa, and Radix inulae, have been found to have various pharmacological actions including anti-inflammatory, antimicrobial, and anticancer properties, with no significant toxicity. Recently, the anticancer activity of alantolactone and isoalantolactone has been extensively investigated. Here, our aim is to review their natural sources and their anticancer activity with specific emphasis on mechanism of actions, by which these compounds act on apoptosis pathways. Based on the literature and also on our previous results, alantolactone and isoalantolactone induce apoptosis by targeting multiple cellular signaling pathways that are frequently deregulated in cancers and suggest that their simultaneous targeting by these compounds could result in efficacious and selective killing of cancer cells. This review suggests that alantolactone and isoalantolactone are potential promising anticancer candidates, but additional studies and clinical trials are required to determine their specific intracellular sites of actions and derivative targets in order to fully understand the mechanisms of therapeutic effects to further validate in cancer chemotherapy.

Pinocembrin: a novel natural compound with versatile pharmacological and biological activities

Pinocembrin (5,7-dihydroxyflavanone) is one of the primary flavonoids isolated from the variety of plants, mainly from Pinus heartwood, Eucalyptus, Populus, Euphorbia, and Sparattosperma leucanthum, in the diverse flora and purified by various chromatographic techniques. Pinocembrin is a major flavonoid molecule incorporated as multifunctional in the pharmaceutical industry. Its vast range of pharmacological activities has been well researched including antimicrobial, anti-inflammatory, antioxidant, and anticancer activities. In addition, pinocembrin can be used as neuroprotective against cerebral ischemic injury with a wide therapeutic time window, which may be attributed to its antiexcitotoxic effects. Pinocembrin exhibits pharmacological effects on almost all systems, and our aim is to review the pharmacological and therapeutic applications of pinocembrin with specific emphasis on mechanisms of actions. The design of new drugs based on the pharmacological effects of pinocembrin could be beneficial. This review suggests that pinocembrin is a potentially promising pharmacological candidate, but additional studies and clinical trials are required to determine its specific intracellular sites of action and derivative targets in order to fully understand the mechanism of its anti-inflammatory, anticancer, and apoptotic effects to further validate its medical applications.

Reactive oxygen species mediate isoalantolactone-induced apoptosis in human prostate cancer cells

Isoalantolactone, a medicinal plant-derived natural compound, is known to induce apoptosis in various cancer cell lines. However, its effect on apoptosis in prostate cancer cells has not been addressed. Thus, we examined the effects of isoalantolactone on prostate cancer cells. It was found that isoalantolactone inhibits growth of both androgen-sensitive (LNCaP) as well as androgen-independent (PC3 and DU-145) prostate cancer cells in a dose-dependent manner. Furthermore, our results indicate that isoalantolactone-induced apoptosis in prostate cancer PC3 cells is associated with the generation of ROS and dissipation of mitochondrial membrane potential (Δψm). In addition, isoalantolactone triggers apoptosis in prostate cancer cells via up-regulation of Bax, down-regulation of Bcl-2, survivin, and significant activation of caspase-3. Isoalantolactone-induced apoptosis is markedly abrogated when the cells were pretreated with N-acetylcysteine (NAC), a specific ROS inhibitor, suggesting that the apoptosis-inducing effect of isoalantolactone in prostate cancer cells is mediated by reactive oxygen species. These findings indicate that isoalantolactone induces reactive oxygen species-dependent apoptosis in prostate cancer cells via a novel mechanism involving inhibition of survivin and provide the rationale for further in vivo and preclinical investigation of isoalantolactone against human prostate cancer.

Induction of apoptosis by costunolide in bladder cancer cells is mediated through ROS generation and mitochondrial dysfunction

Despite the availability of several therapeutic options, a safer and more effective modality is urgently needed for treatment of bladder cancer. Costunolide, a member of sesquiterpene lactone family, possesses potent anticancer properties. In this study, for the first time we investigated the effects of costunolide on the cell viability and apoptosis in human bladder cancer T24 cells. Treatment of T24 cells with costunolide resulted in a dose-dependent inhibition of cell viability and induction of apoptosis which was associated with the generation of ROS and disruption of mitochondrial membrane potential (Δψm). These effects were significantly blocked when the cells were pretreated with N-acetyl- cysteine (NAC), a specific ROS inhibitor. Exposure of T24 cells to costunolide was also associated with increased expression of Bax, down-regulation of Bcl-2, survivin and significant activation of caspase-3, and its downstream target PARP. These findings provide the rationale for further in vivo and clinical investigation of costunolide against human bladder cancer.

Demethoxycurcumin Retards Cell Growth and Induces Apoptosis in Human Brain Malignant Glioma GBM 8401 Cells

Demethoxycurcumin (DMC; a curcumin-related demethoxy compound) has been recently shown to display antioxidant and antitumor activities. It has also produced a potent chemopreventive action against cancer. In the present study, the antiproliferation (using the MTT assay, DMC was found to have cytotoxic activities against GBM 8401 cell with IC₅₀ values at 22.71 μM) and induced apoptosis effects of DMC have been investigated in human brain malignant glioma GBM 8401 cells. We have studied the mitochondrial membrane potential (MMP), DNA fragmentation, caspase activation, and NF-κB transcriptional factor activity. By these approaches, our results indicated that DMC has produced an inhibition of cell proliferation as well as the activation of apoptosis in GBM 8401 cells. Both effects were observed to increase in proportion with the dosage of DMC treatment, and the apoptosis was induced by DMC in human brain malignant glioma GBM 8401 cells via mitochondria- and caspase-dependent pathways.