Strong Growth Inhibitory Effect Research Articles

Cytotoxicity of tubeimoside I in human choriocarcinoma JEG-3 cells by induction of cytochrome c release and apoptosis via the mitochondrial-related signaling pathway

Mitochondria play important roles in the intrinsic pathways that trigger apoptosis. Anticancer chemotherapies eliminate cancer cells mainly through the induction of apoptosis. In the present study, we investigated the mechanism of the cytotoxic effects of tubeimoside I (TBMS1) on the human choriocarcinoma cell line (JEG-3). Choriocarcinoma is one of the most common malignant tumors in the reproductive system. TBMS1, a triterpenoid saponin, isolated from the tubers of Bolbostemma paniculatum (Maxim) Franquet (Cucurbitaceae), showed potent antitumor effects. However, the potential roles of TBMS1 in the treatment of choriocarcinoma remain unknown. In the present study, we examined the effects of TBMS1 on JEG-3 cells. TBMS1 displayed strong growth inhibitory effects on JEG-3 cell growth. In addition, TBMS1 treatment with TBMS1 led to marked cell apoptosis, significant cell cycle arrest at G2 phase and decrease in mitochondrial transmembrane potential (ΔΨm). Cytochrome c was released from the mitochondria and caspase-3 expression was enhanced. Furthermore, TBMS1 induced the up-regulation of Bcl-2 associated X protein (Bax) expression, down-regulation of Bcl-2 expression, inhibition of nuclear factor-κ-B (NF-κB) function and impacted the phosphorylation of p38 mitogen-activated protein kinase (p38/MAPK), extracellular signal-regulated kinases (ERK)1/2 and protein kinase B (Akt). Taken together, our findings suggest that TBMS1 is an efficient apoptosis-inducing agent for choriocarcinoma cells, which exerts its effects, at least partially, by the induction of mitochondrial dysfunction and regulation of the p38/MAPK, ERK1/2 and PI3K/Akt signaling pathways.

Abstract 855: Flavokawain A inhibits urinary bladder cancer in UPII-mutant Ha-ras transgenic mouse bladder cancer model

Abstract Flavokawain A is the predominant chalcone identified from kava extract. We have recently shown that flavokawain A exhibited strong growth inhibitory effects on human bladder cancer cells both in vitro in cell cultures and in vivo in a xenograft mouse model. To examine whether flavokawain A affects specific-stages or course of bladder cancer development, the UPII-mutant Ha-ras transgenic mouse bladder model that mimics human papillary transitional cell carcinoma was used. The homozygous mutant Ha-ras transgenic mice were identified through genotyping using Southern blotting analysis and fed orally with 1g flavokawain A/kg food or 6 g flavokawain A /kg food for 3 or 6 months starting at 6 weeks of age. After treatments, organs are collected and weighted. H&E staining and immunohistochemstry were used to evaluate bladder cancer pathology and expression of biomarkers. All control food- fed male mice died of ureter obstruction and nephrohydrosis within 6 months of treatment, while more than 50% of mice fed with 6g flavokawain A /kg food for 6 months survived beyond the 6 months of treatment. The mean bladder weight in 6g flavokawain /kg food fed male mice also decreased by 66% compared to control treated mice for 3 months. Mouse pathology analysis showed that control mice exhibited poorly differentiated transitional cell carcinoma, while that flavokawain A treated mice presented well differentiated tumors. Compared to the dose of 6g/kg, a 1g/kg dose of flavokawain A is less effective in inhibition of bladder cancer development in this transgenic model. In addition, immunohistochemistry staining of Skp2 revealed that Skp2 oncoprotein expression in urothelium was also significantly decreased in flavorkawain A treatment group compared to control group. Taken together, our results suggest the potential usefulness of flavokawain A in treatment of superficial urinary bladder cancer. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 855. doi:10.1158/1538-7445.AM2011-855

The effects of omega‐3 fatty acids and bexarotene on human breast cancer progression

Breast cancer cell growth can be inhibited by retinoid X receptor (RXR) specific retinoids. Omega‐3 fatty acids share growth regulatory effects similar to those noted when breast cancer cells are treated with RXR specific retinoids. One synthetic RXR‐selective retinoid ligand, bexarotene (LCD 1069, Targretin), is an effective antineoplastic agent in rodent mammary carcinoma models. It is also used clinically to treat cancer patients. Of concern is that some patients are unable to tolerate high doses of treatment drugs. We hypothesized that omega‐3 fatty acids and bexarotene may work synergistically to slow breast cancer cell growth. To facilitate this study, we used an in vitro cell culture model to investigate the relationship between α‐Linolenic acid (ALA), Docosahexaenoic acid (DHA) and Eicosapentaenoic acid (EPA) alone and in conjunction with bexarotene on MCF‐7 cell growth. Following a 72 hr incubation, neither bexarotene nor ALA altered cell growth. DHA alone and in combination with bexarotene showed a strong growth inhibitory effect. EPA alone was not as effective in altering cell growth. Interestingly, when combined with bexarotene, EPA tended to slow growth more that when cells received EPA alone. Thus, select omega‐3 fatty acids are most effective in slowing breast cancer cell progression, and may even enhance the uptake of retinoid treatment drugs and help potentiate their efficacy.

Hexahydro-β-acids induce apoptosis through mitochondrial pathway, GADD153 expression, and caspase activation in human leukemia cells

Hexahydro-β-acids (HBA) and β-acids (BA) displayed strong growth inhibitory effects against human leukemia HL-60 cells and were able to induce apoptosis in a concentration- and time-dependent manner and the morphological changes associated with apoptotic cell death; however, BA was less effective. Treatment with HBA caused a rapid loss of mitochondrial trans-membrane potential, release of mitochondrial cytochrome c into cytosol. The levels of Bad and Bax were dramatically increased in cells treated with HBA. In addition, the results showed that HBA promoted the up-regulation of Fas prior to the processing and activation of pro-caspase-8 and cleavage of Bid, suggesting the involvement of a Fas-mediated pathway in HBA-induced cells. Moreover, the changes occurred after single breaks in DNA were detected, suggesting that HBA induced irreparable DNA damage, which in turn triggered the process of apoptosis. HBA markedly enhanced the growth arrest DNA damage-inducible gene 153 (GADD153) protein in a concentration- and time-dependent manner. These findings suggest that HBA creates an oxidative cellular environment that induces DNA damage and GADD153 gene activation, which in turn triggers apoptosis in HL-60 cells. Our study identified the novel mechanisms of HBA-induced apoptosis and indicated that HBA may be used as a potential chemopreventive and chemotherapeutic agent.

Naftopidil, a Selective α1-Adrenoceptor Antagonist, Suppresses Human Prostate Tumor Growth by Altering Interactions between Tumor Cells and Stroma

In prostate cancer, tumor-stroma interactions play a critical role in the promotion of tumorigenesis, and thus the prevention of those interactions is a promising target to suppress tumor growth. Several studies demonstrated that alpha(1)-adrenoceptor (α(1)-AR) antagonists, therapeutic drugs for benign prostatic hyperplasia, have growth inhibitory effects on human prostate cancer (PCa) cells through induction of apoptosis or G(1) cell-cycle arrest. However, their direct actions on stromal cells surrounding cancer cells have not yet been elucidated. In this study, we investigated the effects of subtype-selective α(1)-AR antagonists (naftopidil, tamsulosin, and silodosin) on prostate tumor growth with a focus on the role of stroma, using commercially available fibroblast cells (PrSC). Tumorigenic studies in vivo showed significant reductions in tumor growth when E9 cells (an androgen low-sensitive LNCaP subline) grafted with PrSC were treated with naftopidil. In in vitro analyses, naftopidil and silodosin showed antiproliferative effects on PCa cells regardless of androgen sensitivity and α(1)-AR subtype expression. In PrSC, a strong growth inhibitory effect was observed with naftopidil but not silodosin. Flow cytometric analysis revealed that naftopidil, but not silodosin, induced G(1) cell-cycle arrest in both PCa cells and PrSC. In naftopidil-treated PrSC, total interleukin-6 protein was significantly reduced with increased suppression of cell proliferation. Silodosin induced weak early apoptosis only in PCa cells. These findings demonstrated that naftopidil strongly suppressed cell proliferation of stromal cells, resulting in decreased tumorigenic soluble factor, suggesting that naftopidil might be effective in preventing stromal support of tumor cells.

The Effects of n-3 Fatty Acids and Bexarotene on Breast Cancer Cell Progression

Breast cancer cell growth can be inhibited in vivo by retinoid X receptor (RXR) specific retinoids. In both animal and cell culture studies, omega-3 fatty acids share growth regulatory effects similar to those of RXR specific retinoids (rexinoids). One synthetic rexinoid, bexarotene (LCD 1069, Targretin), is used clinically to treat cancer patients. Of concern is that some patients are unable to tolerate high doses of such treatment drugs. We hypothesized that n-3 fatty acids and bexarotene may work synergistically to slow breast cancer cell growth. To test our hypothesis, we used MCF-7 human mammary carcinoma cells and an in vitro cell culture model. We investigated the relationship between the omega-3 fatty acids docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) alone and in conjunction with bexarotene in slowing MCF-7 cell growth. Following a 72 hr incubation with the respective treatments, bexarotene enhanced cell growth (p < 0.05) while DHA showed a strong growth inhibitory effect which was not enhanced by the addition of bexarotene (p < 0.05). EPA alone was not effective in altering cell growth (p < 0.05). Interestingly, when combined with bexarotene, EPA was more effective at slowing cell growth than when cells received EPA alone. Thus, select omega-3 fatty acids alone are more effective than bexarotene in slowing MCF-7 cell progression. However, the use of the RXR-selective retinoids may enhance the growth regulatory mechanisms of the fatty acid EPA.

Tetrandrine Induces Apoptosis and Triggers Caspase Cascade in Human Bladder Cancer Cells

Tetrandrine is known to exert anti-tumor effects, however, little is known about its effect on human bladder carcinoma. In this study, employing two different human bladder cancer cell lines, 5637 and T24, which represent high-risk superficial bladder cancer (5637) and high-grade bladder cancer (T24), we tested tetrandrine-induced apoptosis and growth inhibition in bladder carcinoma cell lines and investigated the possible mechanisms. Growth inhibition and apoptosis induction was determined by MTT assay and flow cytometry analysis, respectively. Activation of caspases were analyzed by Western blotting and caspase colorimetric assay. The collapse of mitochondrial membrane potential (ΔΨ(m)) and subcellular distribution of cytochrome c was determined by JC-1 staining and Western blotting, respectively. Tetrandrine treatment showed strong growth inhibitory and apoptotic effects on human bladder cancer 5637 and T24 cells in a concentration-dependent manner. Additionally, induction of apoptosis by tetrandrine was associated with a very strong and prominent caspase-9, caspase-8, and caspase-3 activation as well as PARP cleavage. Flow cytometric studies revealed that tetrandrine induced a dose-dependent loss of ΔΨ(m), which was accompanied by the release of cytochrome c from mitochondria to the cytosol. Taken together, this study provided the first evidence that tetrandrine imparted inhibitory and apoptotic activity in human bladder cancer cells. The tetrandrine-induced apoptosis might be related to the activation of the caspase cascade and mitochondrial pathway. Our results suggest that tetrandrine merits further in vivo investigation as a novel bladder cancer chemopreventive and chemotherapeutic agent in the clinical setting.

Abstract 5513: Synergistic antitumor activity of NK012, a micelle-forming macromolecular prodrug of SN-38, combined with platinum compounds in human cancer xenograft models

Abstract Irinotecan (CPT-11) is clinically used to treat various tumors, but low enzymatic conversion to its active metabolite, SN-38, limits its therapeutic effect. NK012, a micelle-forming macromolecular prodrug of SN-38, accumulates in tumor tissue and gradually releases SN-38 in enzyme-independent manner. NK012 showed much stronger growth inhibitory effects than CPT-11 at maximum tolerated dose (MTD) against all tested xenografted human tumors. Furthermore, NK012 showed much stronger antitumor activities than other cytotoxic agents clinically used for cancer treatment (taxanes, doxorubicin, carboplatin etc.). Here, we report combination antitumor effects of NK012 with platinum compounds in human breast cancer, non-small cell lung cancer, colorectal cancer and hepatocellular cancer xenografts in nude mice. The dose of NK012 was set at 1.9-3.8 mg/kg/day to be sub-optimum for complete regression depending on the cell line. NK012 and carboplatin were administered by q7dx3. Although both of NK012 and carboplatin were ineffective as single agent (minimum T/C values &amp;gt;50%), their combination was effective (minimum T/C value = 8%) to cause tumor regression in MC-05-JCK breast cancer. In MC-05-JCK breast cancer, the TGDs (Tumor Growth Delay; tumor tripling time over control group delayed by treatment / tumor tripling time of control group × 100) by NK012 1.9 mg/kg/day, carboplatin 50 mg/kg/day (67% of MTD), and their combination were 41%, 29%, and 286%, respectively. In NCI-H460 non-small cell lung cancer, the TGDs by NK012 3.8 mg/kg/day, carboplatin 75 mg/kg/day (MTD), and their combination were 90%, 71%, and 403%, respectively. In Co-3 colorectal cancer, the TGDs by NK012 3.8 mg/kg/day, carboplatin 75 mg/kg/day, and their combination were 358%, 97%, and &amp;gt;489%, respectively. Thus, combination of NK012 with carboplatin showed remarkably synergistic effects, and it didn't accompany toxicity exacerbation. Similarly, combination of NK012 with cisplatin exhibited remarkable synergistic effects in Li-07-JCK hepatocellular cancer. The TGDs by NK012 3.8 mg/kg, one shot, cisplatin 10 mg/kg, one shot, and their combination were 58%, 136%, and 455%, respectively. These results indicate that NK012 and platinum compounds combination regimen would be effective for treatment of patients with solid tumors including breast, non-small cell lung, colorectal and hepatocellular carcinomas. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 5513.

Abstract 1691: Apoptotic and antitumor effects of rotenone in MCF-7 human breast cancer cells are mediated ROS through activating JNK and p38 MAPK signaling

Abstract Rotenone is a natural hydrophobic pesticide derived from the roots of Derris and Lonchorcarpus species. The pesticidal activity of rotenone is attributed to irreversible binding and inactivation of complex of the mitochondrial transport chain. This can block electron transport from complex to ubiquinone, resulting in a blockage of the oxidative phosphorylation process, and an increase of the reactive oxygen species (ROS). Rotenone has been shown to display anticancer activity through the induction of apoptosis in various cancer cells. However, the underlying mechanism is still not fully elucidated. In the present study, rotenone showed a strong growth inhibitory effect against human breast MCF-7 cells. DNA flow cytometric analysis, chromatin condensation and poly(ADP-ribose) polymerase (PARP) cleavage indicated rotenone actively induced apoptosis in MCF-7 cells. The anti-apoptotic protein BCl-2, was decreased, whereas the apoptotic protein, Bax, was increased in a time-dependent manner in rotenone-induced apoptosis. Moreover. The treatment of rotenone in MCF-7 cells caused the activation of c-jun N-terminal kinase (JNK) and p38 mitogen-activated protein kinase (MAPKs) and the inactivation of extracellular signal-regulated protein kinase1/2 (ERK1/2). The pharmacological inhibitor of JNK and p38 MAPK revealed significant protection against rotenone-induced apoptosis. In summary, these results indicate rotenone may induce apoptosis through ROS and JNK/p38MAPK activation in MCF-7 cells. In conclusion, we examines the molecular mechanism involved in rotenone-induced apoptosis in human breast cancer MCF-7 cells. We have demonstrated a sequential events that rotenone-induced apoptosis in the cells through ROS generation, which serves as a pivotal upstream function in activating JNK and p38MAPKs, which leads to a decrease of BCl-2 and increase of Bax and finally to inducing apoptosis. Note: This abstract was not presented at the AACR 101st Annual Meeting 2010 because the presenter was unable to attend. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 1691.

Structural and functional studies of leptins from hibernating and non-hibernating bats

Leptin, a 16-kDa hormone produced by mature adipocytes, has been shown to regulate the hibernation of mammals. In this study, the leptin gene sequences of both hibernating ( Rhinolophus ferrumequinum) and non-hibernating ( Rousettus leschenaultii) bats were determined, and the leptin proteins from these two different species of bats were expressed in Escherichia coli for the first time. Results showed that the amino acid sequence of the leptin protein from hibernating bats had a lower degree of identity than that from non-hibernating bats to those of several non-hibernating mammals. The leptin protein of hibernating bats had a stronger growth inhibitory effect on 3T3-L1 cells than that of non-hibernating bats. Structural modeling revealed that the structures of the receptor binding site III, which is critical for signal transduction, of the two bat leptins were very different. Similar to the human leptin, the leptin protein of non-hibernating bats was predicted to have a random loop, whereas that of hibernating bats had a helical structure in this region. This observation provided a clue as to the differential effects of the two different leptins on 3T3-L1 cells.

Synergistic inhibition of colon cancer cell growth by 5‐hydroxy nobiletin and atorvastatin

Due to potential synergistic interactions, combination of different bioactive agents may provide enhanced beneficial effects over single agent administration. We investigated the effects of a unique combination of 5‐hydroxy nobiletin (5HN, a novel flavonoid from orange) and atorvastatin (ATS, Lipitor, a lipid‐lowering drug) on human colon cancer cells. The 5HN/ATS combination produced much stronger growth inhibitory effects on cancer cells than the two agents alone. As determined by isobologram analysis, the enhanced inhibitory effects by the combination were highly synergistic. Flow cytometry analysis showed that the combined treatment caused cell cycle arrest at G0/G1 phase at 24 hr, and induced extensive apoptosis at 48 hr. These effects were much stronger than those produced by 5HN or ATS alone. The combinational effects of 5HN/ATS were associated with profound changes in oncogenic proteins, e.g., increased levels of p21(Cip1/Waf1)and p27(Kip1); decreased levels of CDK2, CDK4, CDK6, Cyclin D1 and hyper‐p‐Rb; and activation of caspase cascade. The combination also synergistically modified plasma membrane‐associated proteins (e.g., K‐Ras and EGFR) and their downstream effectors (e.g., Akt). In summary, our results convincingly demonstrated a strong synergy between 5HN and ATS in inhibiting human colon cancer cells, which warrants further investigation on the in vivo efficacy of this combination.

Butyrate induces cell apoptosis through activation of JNK MAP kinase pathway in human colon cancer RKO cells

Butyrate has been shown to display anti-cancer activity through the induction of apoptosis in various cancer cells. However, the underlying mechanism involved in butyrate-induced apoptosis is still not fully understood. Here, we investigated the cytotoxicity mechanism of butyrate in human colon cancer RKO cells. The results showed that butyrate induced a strong growth inhibitory effect against RKO cells. Butyrate also effectively induced apoptosis in RKO cells, which was characterized by DNA fragmentation, nuclear staining of DAPI, and the activation of caspase-9 and caspase-3. The expression of anti-apoptotic protein Bcl-2 decreased, whereas the apoptotic protein Bax increased in a dose-dependent manner during butyrate-induced apoptosis. Moreover, treatment of RKO cells with butyrate induced a sustained activation of the phosphorylation of c-jun N-terminal kinase (JNK) in a dose- and time-dependent manner, and the pharmacological inhibition of JNK MAPK by SP600125 significantly abolished the butyrate-induced apoptosis in RKO cells. These results suggest that butyrate acts on RKO cells via the JNK but not the p38 pathway. Butyrate triggered the caspase apoptotic pathway, indicated by an enhanced Bax-to-Bcl-2 expression ratio and caspase cascade reaction, which was blocked by SP600125. Taken together, our data indicate that butyrate induces apoptosis through JNK MAPK activation in colon cancer RKO cells.

Modulation of stress genes expression profile by nitric oxide-releasing aspirin in Jurkat T leukemia cells

NO-donating aspirin (NO-ASA, para isomer) has been reported to exhibit strong growth inhibitory effect in Jurkat T-acute lymphoblastic leukemia (T-ALL) cells mediated in part by β-catenin degradation and caspase activation, but the mechanism(s) still remains unclear. In this study, DNA oligoarrays with 263 genes were used to examine the gene expression profiles relating to stress and drug metabolism, and characterize the stress responses at IC 50 and subIC 50 concentrations of p-NO-ASA (20 and 10 μM, respectively) in Jurkat T cells. A total of 22 genes related to heat shock response, apoptosis signaling, detoxifiers and Phase II enzymes, and regulators of cell growth were altered in expression by array analysis based on the expression fold change criteria of ≥1.5-fold or ≤0.65-fold. Real time quantitative RT-PCR confirmed that 20 μM p-NO-ASA strongly upregulated the mRNA levels of two heat shock genes HSPA1A (41.5 ± 7.01-fold) and HSPA6 (100.4 ± 8.11-fold), and FOS (16.2 ± 3.2-fold), moderately upregulated HSPH1 (1.71 ± 0.43-fold) , FMO4 (4.5 ± 1.67-fold), CASP9 (1.77 ± 0.03-fold), DDIT3 (5.6 ± 0.51-fold), and downregulated NF- κB1 (0.54 ± 0.01-fold) and CCND1 (0.69 ± 0.06-fold). Protein levels of Hsp70, the product of HSPA1A, and fos were increased in p-NO-ASA-treated Jurkat T and HT-29 colon cancer cells in a dose-dependent manner. Silencing of Hsp70 enhanced the growth inhibitory effect of p-NO-ASA at low concentrations. The altered gene expression patterns by NO-ASA in Jurkat T cells suggest mechanisms for carcinogen metabolism, anti-proliferative activity and possible chemoprotective activity in T-ALL.

Rotenone induces apoptosis in MCF‐7 human breast cancer cell‐mediated ROS through JNK and p38 signaling

Rotenone is an inhibitor of the mitochondrial electron transport chain complex I, resulting in the generation of reactive oxygen species (ROS). Rotenone has been shown to display anticancer activity through the induction of apoptosis in various cancer cells. However, the underlying mechanism is still not fully understood. Here, rotenone showed a strong growth inhibitory effect against human breast cancer MCF-7 cells. DNA flow cytometric analysis, chromatin condensation, and poly (ADP-ribose) polymerase (PARP) cleavage indicated rotenone actively induced apoptosis in MCF-7 cells. The antiapoptotic protein, Bcl-2, was decreased, whereas the apoptotic protein, Bax, was increased in a time-dependent manner in rotenone-induced apoptosis. Moreover, the treatment of rotenone in MCF-7 cells caused the activation of c-jun N-terminal kinase (JNK) and p38 mitogen-activated protein kinases (MAPKs), and the inactivation of extracellular signal-regulated protein kinase 1/2 (ERK1/2). The pharmacological inhibition of JNK and p38 MAPK revealed significant protection against rotenone-induced apoptosis. Taken together, these results indicate rotenone may induce apoptosis through ROS and JNK/p38 MAPKs activation in MCF-7 cells.

Auxin regulation of gibberellin biosynthesis in the roots of pea (Pisum sativum).

Auxin promotes GA biosynthesis in the aboveground parts of plants. However, it has not been demonstrated previously that this interaction occurs in roots. To understand the interactions between auxin and GAs in these organs, we treated wild-type pea (Pisum sativum L.) roots with the inhibitors of auxin action, p-chlorophenoxyisobutyric acid (PCIB) and yokonolide B (YkB), and with the auxin transport inhibitor N-1-naphthylphthalamic acid (NPA). These compounds generally downregulated GA synthesis genes and upregulated GA deactivation genes, and reduced the level of the bioactive GA1. These effects indicate that in pea roots, auxin at normal endogenous levels stimulates GA biosynthesis. We show also that supra-optimal levels of exogenous auxin reduce the endogenous level of bioactive GA in roots, although the effect appears too small to account for the strong growth-inhibitory effect of high auxin levels.

Growth Inhibition and Induction of Apoptosis of Colon Cancer Cell Lines by Applying Marine Phospholipid

Polyunsaturated fatty acids (PUFAs) exhibit beneficial biological functions in carcinogenic processes. We examined the effects of PUFAs in the acid and phospholipid forms on three colon cancer cell lines (HT-29, Caco-2, and DLD-1). Docosahexaenoic acid (DHA) and eicosapentaenoic (EPA) in both acid and phospholipid forms showed growth inhibition effects on experimental colon cancer cell lines. But these PUFAs had the strongest growth-inhibitory effect on HT-29 than Caco-2 and DLD-1. Combined application of PUFAs and sodium butyrate (NaBt) increased the growth inhibition. Growth inhibition was apparently caused by increased lipid peroxidation. DHA or EPA in combination with NaBt significantly increased caspase-3 activity compared to control. DHA and DHA-rich phosphatidylcholine decreased Bcl-2 level in HT-29 and Caco-2 cells.

Grape Seed Extract Induces Cell Cycle Arrest and Apoptosis in Human Colon Carcinoma Cells

One approach to control colorectal cancer (CRC) is its preventive intervention by dietary agents or those consumed as supplements. However, because most of these products are often consumed by patients as an complementary and alternative medicine practice, a scientific base such as efficacy, mechanism, and standardized preparation needs to be developed. Grape seed extract (GSE) is one such supplement widely consumed by humans for its several health benefits. We reported recently that GSE inhibits CRC cell HT29 growth in culture and nude mice xenograft. Because GSE is available commercially through different vendors, here we assessed whether GSE from 2 different manufacturers produces comparable biological effects in a panel of human CRC cell lines. Our results show that irrespective of source, GSE strongly inhibits LoVo, HT29, and SW480 cell growth, with a G1 arrest in LoVo and HT29 cells but an S and/or G2/M arrest in SW480 cell cycle progression. GSE also induced Cip/p21 levels in all 3 cell lines. Furthermore, an induction of apoptosis was observed in all 3 cell lines by GSE. Taken together, our findings suggest that GSE could be an effective CAM agent against CRC possibly due to its strong growth inhibitory and apoptosis-inducing effects.

Withaferin A induces apoptosis by activating p38 mitogen-activated protein kinase signaling cascade in leukemic cells of lymphoid and myeloid origin through mitochondrial death cascade

Withaferin A (WA) is present abundantly in Withania somnifera, a well-known Indian medicinal plant. Here we demonstrate how WA exhibits a strong growth-inhibitory effect on several human leukemic cell lines and on primary cells from patients with lymphoblastic and myeloid leukemia in a dose-dependent manner, showing no toxicity on normal human lymphocytes and primitive hematopoietic progenitor cells. WA-mediated decrease in cell viability was observed through apoptosis as demonstrated by externalization of phosphatidylserine, a time-dependent increase in Bax/Bcl-2 ratio; loss of mitochondrial transmembrane potential, cytochrome c release, caspases 9 and 3 activation; and accumulation of cells in sub-G0 region based on DNA fragmentation. A search for the downstream pathway further reveals that WA-induced apoptosis was mediated by an increase in phosphorylated p38MAPK expression, which further activated downstream signaling by phosphorylating ATF-2 and HSP27 in leukemic cells. The RNA interference of p38MAPK protected these cells from WA-induced apoptosis. The RNAi knockdown of p38MAPK inhibited active phosphorylation of p38MAPK, Bax expression, activation of caspase 3 and increase in Annexin V positivity. Altogether, these findings suggest that p38MAPK in leukemic cells promotes WA-induced apoptosis. WA caused increased levels of Bax in response to MAPK signaling, which resulted in the initiation of mitochondrial death cascade, and therefore it holds promise as a new, alternative, inexpensive chemotherapeutic agent for the treatment of patients with leukemia of both lymphoid and myeloid origin.

The Growth-Inhibitory Effects of Dexamethasone on Renal Cell Carcinoma In Vivo and In Vitro

Background: Recently, several kinase inhibitors have been reported to exert stronger growth inhibitory effects on metastatic renal cell carcinomas (RCCs) than cytokines such as interferons (IFNs) and interleukin-2 (IL-2). On the contrary, the adverse effects of these drugs are also severe. The aim of this study is to analyze the growth-inhibitory effects of DEXamethasone (DEX) on RCC in vivo and in vitro. Methods: The MTT assay was performed using three RCC cell lines, OUR-10, Caki-1, and NC65. OUR-10 cells were subcutaneously transplanted to the dorsal area of nude mice. The nuclear translocation of glucocorticoid receptor (GR) and NF-κ B was examined using appropriate antibodies. Concentrations of interleukin-6 (IL-6), IL-8, and vascular endothelial cell growth factor (VEGF) in the conditioned media and cytosol were measured by enzyme-linked immunosorbent assay (ELISA). Results: All three RCC cell lines responded to DEX treatment. The growth of OUR-10 xenografts was significantly inhibited by administration of DEX. GR was translocated into the nucleus on DEX treatment. Intracellular IL-6, as well as IL-6 in the conditioned medium, decreased in OUR-10 cells following treatment with increasing amounts of DEX. Concentrations of IL-8 and VEGF in the conditioned medium of OUR-10 and NC65 cells also decreased following DEX treatment, with the inhibition of nuclear translocation of NF-κ B. Conclusion: DEX treatment is a candidate for advanced RCC therapy by inhibiting the activation of NF-κ B and its downstream products such as IL-6, IL-8 and VEGF.

Up-regulation ofyggGpromotes the survival ofEscherichia colicells containing Era-1 mutant protein

Era is a highly conserved GTPase essential for bacterial growth. Using a digoxigenin-labeled Era protein to screen a phage expression library of Escherichia coli genomic DNA, yggG, a gene that encodes a putative zinc metalloprotease was isolated and characterized. The deduced amino acid sequence of YggG showed high degrees of similarity to some reported heat shock proteins. In this study, the direct interaction between Era and YggG was confirmed, and it was found that the yggG gene, encoding a 25 kDa heat shock protein, was up-regulated at the mRNA level in partially defective Era GTPase mutants (era-1) and in E. coli cells overproducing Era-1. The delta yggG strain displayed the same growth rate as wild-type strain under normal growth conditions and after heat shock. Overexpression of Era-1 in the delta yggG strain resulted in a stronger growth-inhibitory effect than that in the wild-type strain, while coexpression of YggG partially restored the bacterial growth rate. The results indicated that YggG expression is significantly increased in response to stress caused by the Era-1 mutant protein in E. coli, thus promoting the growth of E. coli.