Capsaicin induced cell cycle arrest and apoptosis in human esophagus epidermoid carcinoma CE 81T/VGH cells through the elevation of intracellular reactive oxygen species and Ca2+ productions and caspase-3 activation

Capsaicin represses transcriptional activity of β-catenin in human colorectal cancer cells

Capsaicin is a pungent ingredient in chili red peppers and has been linked to suppression of growth in various cancer cells. However, the underlying mechanism(s) by which capsaicin induces growth arrest and apoptosis of cancer cells is not completely understood. In the present study, we investigated whether capsaicin alters β-catenin-dependent signaling in human colorectal cancer cells in vitro. Exposure of SW480, LoVo and HCT-116 cells to capsaicin suppressed cell proliferation. Transient transfection with a β-catenin/T-cell factor (TCF)-responsive reporter indicated that capsaicin suppressed the transcriptional activity of β-catenin/TCF. Capsaicin treatment resulted in a decrease of intracellular β-catenin levels and a reduction of transcripts from the β-catenin gene (CTNNB1). These results were confirmed by a reduced luciferase reporter activity driven by promoter-reporter construct containing the promoter region of the Catnb gene. In addition, capsaicin destabilized β-catenin through enhancement of proteosomal-dependent degradation. Western blot and immunoprecipitation studies indicated that capsaicin treatment suppressed TCF-4 expression and disrupted the interaction of TCF-4 and β-catenin. This study identifies a role for the β-catenin/TCF-dependent pathway that potentially contributes to the anticancer activity of capsaicin in human colorectal cancer cells.

Capsaicin may slow PSA doubling time: case report and literature review

Capsaicin is the main pungent component of chili peppers. This is the first case, to our knowledge, that describes prostate-specific antigen (PSA) stabilization in a patient with prostate cancer, who had biochemical failure after radiation therapy. A 66-year-old male underwent radiotherapy treatment for a T2b, Gleason 7 (3+4) adenocarcinoma of the prostate, with a PSA level of 13.3 ng/mL in April 2001. He had 3-dimensional conformal radiotherapy of 46 Gy in 23 fractions to the prostate and pelvis, and a prostate boost of 30 Gy in 15 fractions. Radiotherapy was completed in May 2001 and PSA nadired in January 2002 (0.57). Due to the continued PSA rise, the patient was started on bicalutamide (50 mg orally, daily) and leuprolide acetate (1 dose of 22.5 mg intramuscularly) in July 2005 when PSA was 38.5 ng/mL. Due to poor tolerance of androgen ablation therapy, the patient discontinued treatment and started taking 2.5 mL of habaneros chili sauce, containing capsaicin, 1 to 2 times a week in April 2006. Prostate-specific antigen doubling time (PSAdt) increased from 4 weeks before capsaicin to 7.3 months by October 2006. From October 2006 until November 2007, the patient remained on capsaicin (2.5 to 15 mL daily) and his PSA was stable (between 11 to 14 ng/mL). By January 2008, his PSA rose to 22.3 and he has maintained a PSAdt between 4 and 5 months, where it presently remains. Due to the patient's continued PSA rise, he was restarted on bicalutamide (12.5 mg daily). Apart from PSA relapse, the patient remains free of signs or symptoms of recurrence.

Antimetastatic effects of Phyllanthus on human lung (A549) and breast (MCF-7) cancer cell lines

Background

Current chemotherapeutic drugs kill cancer cells mainly by inducing apoptosis. However, they become ineffective once cancer cell has the ability to metastasize, hence the poor prognosis and high mortality rate. Therefore, the purpose of this study was to evaluate the antimetastatic potential of Phyllanthus (P. niruri, P. urinaria, P. watsonii, and P. amarus) on lung and breast carcinoma cells.

Methodology/Principal Findings

Cytotoxicity of Phyllanthus plant extracts were first screened using the MTS reduction assay. They were shown to inhibit MCF-7 (breast carcinoma) and A549 (lung carcinoma) cells growth with IC₅₀ values ranging from 50–180 µg/ml and 65–470 µg/ml for methanolic and aqueous extracts respectively. In comparison, they have lower toxicity on normal cells with the cell viability percentage remaining above 50% when treated up to 1000 µg/ml for both extracts. After determining the non-toxic effective dose, several antimetastasis assays were carried out and Phyllanthus extracts were shown to effectively reduce invasion, migration, and adhesion of both MCF-7 and A549 cells in a dose-dependent manner, at concentrations ranging from 20–200 µg/ml for methanolic extracts and 50–500 µg/ml for aqueous extracts. This was followed by an evaluation of the possible modes of cell death that occurred along with the antimetastatic activity. Phyllanthus was shown to be capable of inducing apoptosis in conjunction with its antimetastastic action, with more than three fold increase of caspases-3 and -7, the presence of DNA-fragmentation and TUNEL-positive cells. The ability of Phyllanthus to exert antimetastatic activities is mostly associated to the presence of polyphenol compounds in its extracts.

Conclusions/Significance

The presence of polyphenol compounds in the Phyllanthus plant is critically important in the inhibition of the invasion, migration, and adhesion of cancer cells, along with the involvement of apoptosis induction. Hence, Phyllanthus could be a valuable candidate in the treatment of metastatic cancers.

Capsaicin induces apoptosis through ubiquitin-proteasome system dysfunction

Capsaicin is an active component of red pepper having an antiproliferative effect in a variety of cancer cells, which recent evidence suggests due to its ability to induce apoptosis. However, the molecular mechanisms through which capsaicin induces apoptosis are not well understood. Here we demonstrate that capsaicin-induced apoptosis is mediated via the inhibition cellular proteasome function. Treatment of capsaicin to mouse neuro 2a cells results in the inhibition of proteasome activity in a dose- and time-dependent manner that seems to correlate with its effect on cell death. The effect of capsaicin on cellular proteasome function is indirect and probably mediated via the generation of oxidative stress. Exposure of capsaicin also causes increased accumulation of ubiquitinated proteins as wells as various target substrates of proteasome like p53 and Bax and p27. Like many other classical proteasome inhibitors, capsaicin also triggers the intrinsic pathway of apoptosis involving mitochondria and induces neurite outgrowth. Our results strongly support for the use of capsaicin as an anticancer drug.

Capsaicin displays anti-proliferative activity against human small cell lung cancer in cell culture and nude mice models via the E2F pathway

Background

Small cell lung cancer (SCLC) is characterized by rapid progression and low survival rates. Therefore, novel therapeutic agents are urgently needed for this disease. Capsaicin, the active ingredient of chilli peppers, displays anti-proliferative activity in prostate and epidermoid cancer in vitro. However, the anti-proliferative activity of capsaicin has not been studied in human SCLCs. The present manuscript fills this void of knowledge and explores the anti-proliferative effect of capsaicin in SCLC in vitro and in vivo.

Methodology/Principal Findings

BrdU assays and PCNA ELISAs showed that capsaicin displays robust anti-proliferative activity in four human SCLC cell lines. Furthermore, capsaicin potently suppressed the growth of H69 human SCLC tumors in vivo as ascertained by CAM assays and nude mice models. The second part of our study attempted to provide insight into molecular mechanisms underlying the anti-proliferative activity of capsaicin. We found that the anti-proliferative activity of capsaicin is correlated with a decrease in the expression of E2F-responsive proliferative genes like cyclin E, thymidylate synthase, cdc25A and cdc6, both at mRNA and protein levels. The transcription factor E2F4 mediated the anti-proliferative activity of capsaicin. Ablation of E2F4 levels by siRNA methodology suppressed capsaicin-induced G1 arrest. ChIP assays demonstrated that capsaicin caused the recruitment of E2F4 and p130 on E2F-responsive proliferative promoters, thereby inhibiting cell proliferation.

Conclusions/Significance

Our findings suggest that the anti-proliferative effects of capsaicin could be useful in the therapy of human SCLCs.

NSAID-activated gene-1 as a molecular target for capsaicin-induced apoptosis through a novel molecular mechanism involving GSK3beta, C/EBPbeta and ATF3

Capsaicin, a natural product of the Capsicum species of red peppers, is known to induce apoptosis and suppress growth. Non-steroidal anti-inflammatory drug-activated gene-1 (NAG-1) is a cytokine associated with pro-apoptotic and antitumorigenic property in colorectal and lung cancer. Our data demonstrate that capsaicin leads to induction of apoptosis and up-regulates NAG-1 gene expression at the transcriptional level. Overexpression of CCAAT/enhancer binding protein beta (C/EBPbeta) caused a significant increase of basal and capsaicin-induced NAG-1 promoter activity. We subsequently identified C/EBPbeta binding sites in the NAG-1 promoter responsible for capsaicin-induced NAG-1 transactivation. Electrophoretic mobility shift assay and chromatin immunoprecipitation assay confirmed binding of C/EBPbeta to the NAG-1 promoter. Capsaicin treatment resulted in an increase of phosphorylated serine/threonine residues on C/EBPbeta, and the immunoprecipitation study showed that capsaicin enhanced binding of C/EBPbeta with glycogen synthase kinase 3beta (GSK3beta) and activating transcription factor 3 (ATF3). The phosphorylation and interaction of C/EBPbeta with GSK3beta and ATF3 are decreased by the inhibition of the GSK3beta and Protein Kinase C pathways. Knockdown of C/EBPbeta, GSK3beta or ATF3 ameliorates NAG-1 expression induced by capsaicin treatment. These data indicate that C/EBPbeta phosphorylation through GSK3beta may mediate capsaicin-induced expression of NAG-1 and apoptosis through cooperation with ATF3 in human colorectal cancer cells.

Capsaicin-induced apoptosis is regulated by endoplasmic reticulum stress- and calpain-mediated mitochondrial cell death pathways

Capsaicin, a pungent compound found in hot chili peppers, induces apoptotic cell death in various cell lines, however, the precise apoptosis signaling pathway is unknown. Here, we investigated capsaicin-induced apoptotic signaling in the human breast cell line MCF10A and found that it involves both endoplasmic reticulum (ER) stress and calpain activation. Capsaicin inhibited growth in a dose-dependent manner and induced apoptotic nuclear changes in MCF10A cells. Capsaicin also induced degradation of tumor suppressor p53; this effect was enhanced by the ER stressor tunicamycin. The proteasome inhibitor MG132 completely blocked capsaicin-induced p53 degradation and enhanced apoptotic cell death. Capsaicin treatment triggered ER stress by increasing levels of IRE1, GADD153/Chop, GRP78/Bip, and activated caspase-4. It led to an increase in cytosolic Ca(2+), calpain activation, loss of the mitochondrial transmembrane potential, release of mitochondrial cytochrome c, and caspase-9 and -7 activation. Furthermore, capsaicin-induced the mitochondrial apoptotic pathway through calpain-mediated Bid translocation to the mitochondria and nuclear translocation of apoptosis-inducing factor (AIF). Capsaicin-induced caspase-9, Bid cleavage, and AIF translocation were blocked by calpeptin, and BAPTA and calpeptin attenuated calpain activation and Bid cleavage. Thus, both ER stress- and mitochondria-mediated death pathways are involved in capsaicin-induced apoptosis.

Fas-associated factor 1 is a negative regulator in capsaicin induced cancer cell apoptosis

Vanilloid receptor1 (VR1/TRPV1) is expressed on peripheral nerves and involved in sensing of temperature and pain. Recent reports have demonstrated that tumor cells express TRPV1 and that capsaicin (CP), a ligand for TRPV1, induces apoptosis in cancer cells. The mechanism underlying CP-induced tumor cell apoptosis remains unclear. Here, we investigated the role of TRPV1 in tumor apoptosis using TRPV1-expressing cancer cell lines. We demonstrate that iodo-resiniferatoxin (I-RTX), an antagonist of TRPV1 does not inhibit CP mediated apoptosis nor is it cytotoxic by itself, but acts as a partial agonist and shows synergistic effect with CP. We further demonstrate that CP treatment degrades Fas-associated factor1 (FAF1); a TRPV1 associated protein. Moreover, using RNA interference with small inhibitory RNAs (siRNA) for FAF1 we observed that down-regulation of FAF1 by siRNA makes the cell susceptible to enhanced apoptosis with CP. In summary, our data shows for the first time that the underlying mechanisms of CP-induced cancer cell apoptosis involves FAF1, a TRPV1 associated protein and serves as an important foundation for further understanding of anticancer activity of CP.

Japanese encephalitis virus NS2B-NS3 protease induces caspase 3 activation and mitochondria-mediated apoptosis in human medulloblastoma cells

Japanese encephalitis virus (JEV) causes severe neurological diseases with a high fatality rate. Clinical, neurophysiological and radiological features of Japanese encephalitis JE patients showed that JEV infection resulted in widespread involvement of the nervous system, including thalamus, basal ganglia, brainstem, cerebellum, cerebral cortex and spinal cord. In this study, we characterized the apoptotic effect of JEV infection and its viral proteins on the TE671 human medulloblastoma cells. JEV replicated in TE671 cells, inducing caspase 3-mediated apoptosis in MOI- and time-dependent manners. Of viral proteins, co-expression of JEV NS3 protease with NS2B cofactor significantly induced higher degrees of apoptosis and triggered higher caspase 3 activities than single expression of E, NS1, NS2B or NS3 protease in human medulloblastoma cells. Moreover, JEV NS2B-NS3 protease induced reduction of mitochondrial membrane potential and release of mitochondrial cytochrome C, which were responsible for the mitochondria-mediated apoptosis. In addition, the production of reactive oxygen species production and activation of ASK1-p38 MAPK signaling pathway might be associated with JEV NS2B-NS3 protease-induced mitochondria-mediated apoptosis. The results demonstrated that the JEV infection and the co-expression of JEV NS3 protease with NS2B cofactor induced caspase 3 activation and mitochondria-mediated apoptosis in human medulloblastoma cells, being valuable insight for cellular and molecular levels of JEV pathogenesis.

Potential anticancer properties of the water extract of Inonotus [corrected] obliquus by induction of apoptosis in melanoma B16-F10 cells

ETHNOPHARMACOLOGICAL RELEVANCE

Inonotus obliquus (Chaga mushroom), one of the widely known medicinal mushrooms, has been used to treat various cancers in Russia and most of Baltic countries for many centuries.

AIM OF THE STUDY

To examine the anti-proliferative effects of Inonotus obliquus extract on melanoma B16-F10 cells. Furthermore, to assess the anti-tumor effect of Inonotus obliquus extract in vivo in Balb/c mice.

MATERIALS AND METHODS

The water extract of Inonotus obliquus was studied for anti-proliferative effects on the growth and morphology of B16-F10 melanoma cells and for anti-tumor effect using in vivo in Balb/c mice.

RESULTS

Inonotus obliquus extract not only inhibited the growth of B16-F10 cells by causing cell cycle arrest at G(0)/G(1) phase and apoptosis, but also induced cell differentiation. These effects were associated with the down-regulation of pRb, p53 and p27 expression levels, and further showed that Inonotus obliquus extract resulted in a G(0)/G(1) cell cycle arrest with reduction of cyclin E/D1 and Cdk 2/4 expression levels. Furthermore, the anti-tumor effect of Inonotus obliquus extract was assessed in vivo in Balb/c mice. Intraperitoneal administration of Inonotus obliquus extract significantly inhibited the growth of tumor mass in B16-F10 cells implanted mice, resulting in a 3-fold (relative to the positive control, (*)p<0.05) inhibit at dose of 20mg/kg/day for 10 days.

CONCLUSION

This study showed that the water extract of Inonotus obliquus mushroom exhibited a potential anticancer activity against B16-F10 melanoma cells in vitro and in vivo through the inhibition of proliferation and induction of differentiation and apoptosis of cancer cells.

Spermatogonial stem cell sensitivity to capsaicin: an in vitro study

BACKGROUND

Conflicting reports have been published on the sensitivity of spermatogenesis to capsaicin (CAP), the pungent ingredient of hot chili peppers. Here, the effect of CAP on germ cell survival was investigated by using two testis germ cell lines as a model. As CAP is a potent agonist of the transient receptor potential vanilloid receptor 1 (TRPV1) and no information was available of its expression in germ cells, we also studied the presence of TRPV1 in the cultured cells and in germ cells in situ.

METHODS

The rat spermatogonial stem cell lines Gc-5spg and Gc-6spg were used to study the effects of different concentrations of CAP during 24 and 48 h. The response to CAP was first monitored by phase-contrast microscopy. As germ cells appear to undergo apoptosis in the presence of CAP, the activation of caspase 3 was studied using an anti activated caspase 3 antibody or by quantifying the amount of cells with DNA fragmentation using flow cytometry. Immunolocalization was done with an anti-TRPV1 antibody either with the use of confocal microscopy to follow live cell labeling (germ cells) or on Bouin fixed paraffin embedded testicular tissues. The expression of TRPV1 by the cell lines and germ cells was confirmed by Western blots.

RESULTS

Initial morphological observations indicated that CAP at concentrations ranging from 150 uM to 250 uM and after 24 and 48 h of exposure, had deleterious apoptotic-like effects on both cell lines: A large population of the CAP treated cell cultures showed signs of DNA fragmentation and caspase 3 activation. Quantification of the effect demonstrated a significant effect of CAP with doses of 150 uM in the Gc-5spg cell line and 200 uM in the Gc-6spg cell line, after 24 h of exposure. The effect was dose and time dependent in both cell lines. TRPV1, the receptor for CAP, was found to be expressed by the spermatogonial stem cells in vitro and also by premeiotic germ cells in situ.

CONCLUSION

CAP adversely affects spermatogonial survival in vitro by inducing apoptosis to those cells and TRPV-1, a CAP receptor, may be involved in this effect as this receptor is expressed by mitotic germ cells.

Apoptosis induced by capsaicin in prostate PC-3 cells involves ceramide accumulation, neutral sphingomyelinase, and JNK activation

Numerous studies have recently focused on the anticarcinogenic, antimutagenic, or chemopreventive activities of the main pungent component of red pepper, capsaicin (N-vanillyl-8-methyl-1-nonenamide). We have previously shown that, in the androgen-independent prostate cancer PC-3 cells, capsaicin inhibits cell growth and induces apoptosis through reactive oxygen species (ROS) generation [Apoptosis 11 (2006) 89-99]. In the present study, we investigated the signaling pathways involved in the antiproliferative effect of capsaicin. Here, we report that capsaicin apoptotic effect was mediated by ceramide generation which occurred by sphingomyelin hydrolysis. Using siRNA, we demonstrated that N-SMase expression is required for the effect of capsaicin on prostate cell viability. We then investigated the role of MAP kinase cascades, extracellular signal-regulated protein kinase (ERK), c-Jun N-terminal kinase (JNK), and p38 MAPK, in the antiproliferative effect of capsaicin, and we confirmed that capsaicin could activate ERK and JNK but not p38 MAPK. Pharmacological inhibition of JNK kinase, as well as inhibition of ROS by the reducing agent N-acetylcysteine, prevented ceramide accumulation and capsaicin-induced cell death. However, inhibition of ceramide accumulation by the SMase inhibitor D609 did not modify JNK activation. These data reveal JNK as an upstream regulator of ceramide production. Capsaicin-promoted activation of ERK was prevented with all the inhibitors tested. We conclude that capsaicin induces apoptosis in PC-3 cells via ROS generation, JNK activation, ceramide accumulation, and second, ERK activation.

Effect of chlorhexidine digluconate on different cell types: a molecular and ultrastructural investigation

Although several studies have shown that chlorhexidine digluconate (CHX) has bactericidal activity against periodontal pathogens and exerts toxic effects on periodontal tissues, few have been directed to evaluate the mechanisms underlying its adverse effects on these tissues. Therefore, the aim of the present study was to investigate the in vitro cytotoxicity of CHX on cells that could represent common targets for its action in the surgical procedures for the treatment of periodontitis and peri-implantitis and to elucidate its mechanisms of action. Osteoblastic, endothelial and fibroblastic cell lines were exposed to various concentrations of CHX for different times and assayed for cell viability and cell death. Also analysis of mitochondrial membrane potential, intracellular Ca2+ mobilization and reactive oxygen species (ROS) generation were done in parallel, to correlate CHX-induced cell damage with alterations in key parameters of cell homeostasis. CHX affected cell viability in a dose and time-dependent manners, particularly in osteoblasts. Its toxic effect consisted in the induction of apoptotic and autophagic/necrotic cell deaths and involved disturbance of mitochondrial function, intracellular Ca2+ increase and oxidative stress. These data suggest that CHX is highly cytotoxic in vitro and invite to a more cautioned use of the antiseptic in the oral surgical procedures.