Gallic acid induces G2/M phase cell cycle arrest via regulating 14-3-3β release from Cdc25C and Chk2 activation in human bladder transitional carcinoma cells

Gallic Acid Induces HeLa Cell Lines Apoptosis via the P53/Bax Signaling Pathway

BACKGROUND

Cervical cancer is a type of cancer that originates from the endometrium and is more common in developed countries and its incidence is increasing day by day in developing countries. The most commonly prescribed chemotherapeutic drugs limit their use due to serious side effects and the development of drug resistance. For this reason, interest in new active ingredients obtained from natural products is increasing. This study aimed to reveal the apoptotic and antiproliferative effects of gallic acid and doxorubicin combination therapy against the HeLa cell line.

METHODS

We investigated the anti-cancer effects of doxorubicin and gallic acid in the human HeLa cervical cell line by using the MTT test, Nucblue staining for the identification of apoptotic cells due to nuclear condensation using fluorescent substance, and apoptotic markers P53 and Bax for the RT-PCR test.

RESULTS

The highest cytotoxic effect obtained in the study, the highest increase in apoptotic induction, and a significant difference in P53/Bax levels were seen in the gallic acid/doxorubicin combination. Additionally, it was determined that gallic acid exhibited an effective cytotoxic effect on HeLa and HaCat cells within 48 and 72 h of application.

CONCLUSIONS

The obtained findings show that the gallic acid/doxorubicin combination applied to HeLa cells may be an alternative treatment against both the cytotoxic effect size and the side effects of the chemotherapy agent.

YWHAB is regulated by IRX5 and inhibits the migration and invasion of breast cancer cells

Highly metastatic and heterogeneous breast cancer affects the health of women worldwide. Abnormal expression of tyrosine 3-monooxygenase/tryptophan 5-monooxygenase activation protein β (YWHAB), also known as 14-3-3β, is associated with the tumorigenesis and progression of bladder cancer, lung cancer and hepatocellular carcinoma; however, to the best of our knowledge, the role of YWHAB in breast cancer remains unknown. In the present study, a dual luciferase assay demonstrated that the transcription factor iroquois homeobox 5 may regulate YWHAB expression by affecting the promoter sequence upstream of its transcription start site. Subsequently, it was demonstrated that overexpression of YWHAB did not affect proliferation, but did reduce the migration and invasion of MDA-MB-231 cells. Furthermore, knockdown of YWHAB promoted the migration and invasion of MCF7 cells. Transcriptomics analysis demonstrated that when YWHAB was overexpressed, 61 genes were differentially expressed, of which 43 genes were upregulated and 18 genes were downregulated. These differentially expressed genes (DEGs) were enriched in cancer-related pathways, such as 'TNF signaling pathway' [Kyoto Encyclopedia of Genes and Genomes (KEGG): map04688]. The pathway with the largest number of DEGs was 'Rheumatoid arthritis' (KEGG: map05323). Notably, YWHAB downregulated vimentin, which is a mesenchymal marker, thus suggesting that it may weaken the mesenchymal properties of cells. These findings indicate that YWHAB may be a potential therapeutic target in breast cancer and further work should be performed to assess its actions as a potential tumor suppressor.

Paeonia genus: a systematic review of active ingredients, pharmacological effects and mechanisms, and clinical applications for the treatment of cancer

The main active constituents of plants of the Paeonia genus are known to have antitumor activity. Hundreds of compounds with a wide range of pharmacological activities, including monoterpene glycosides, flavonoids, tannins, stilbenes, triterpenoids, steroids, and phenolic compounds have been isolated. Among them, monoterpenes and their glycosides, flavonoids, phenolic acids, and other constituents have been shown to have good therapeutic effects on various cancers, with the main mechanisms including the induction of apoptosis; the inhibition of tumor cell proliferation, migration, and invasion; and the modulation of immunity. In this study, many citations related to the traditional uses, phytochemical constituents, antitumor effects, and clinical applications of the Paeonia genus were retrieved from popular and widely used databases such as Web of Science, Science Direct, Google Scholar, and PubMed using different search strings. A systematic review of the antitumor constituents of the Paeonia genus and their therapeutic effects on various cancers was conducted and the mechanisms of action and pathways of these phytochemicals were summarised to provide a further basis for antitumor research.

Research progress on the pharmacological mechanism, in vivo metabolism and structural modification of Erianin

Erianin is an important bibenzyl compound in dendrobium and has a wide spectrum of pharmacological properties. Since Erianin was discovered, abundant results have been achieved in the in vitro synthesis, structural modification, and pharmacological mechanism research. Researchers have developed a series of simple and efficient in vitro synthesis methods to improve the shortcomings of poor water solubility by replacing the chemical structure or coating it in nanomaterials. Erianin has a broad anti-tumor spectrum and significant anti-tumor effects. In addition, Erianin also has pharmacological actions like immune regulation, anti-inflammatory, and anti-angiogenesis. A comprehensive understanding of the synthesis, metabolism, structural modification, and pharmacological action pathways of Erianin is of great value for the utilization of Erianin. Therefore, this review conducts a relatively systematic look back at Erianin from the above four aspects, to give a reference for the evolvement and further appliance of Erianin.

Recent advances in ATM inhibitors as potential therapeutic agents

ATM, a member of the PIKK-like protein family, plays a central role in responding to DNA double-strand breaks and other lesions to protect the genome against DNA damage. Loss of ATM's kinase function has been shown to increase the sensitivity of most cells to ionizing radiation. Therefore, ATM is thought to be a promising target for chemotherapy as a radiotherapy sensitizer. The mechanism of ATM in cancer treatment and the development of its inhibitors have become research hotspots. Here we present an overview of research concerning ATM protein domains, functions and inhibitors, as well as perspectives and insights for future development of ATM-targeting agents.

Gallic Acid: A Dietary Polyphenol that Exhibits Anti-neoplastic Activities by Modulating Multiple Oncogenic Targets

Phytochemicals are being used for thousands of years to prevent dreadful malignancy. Side effects of existing allopathic treatment have also initiated intense research in the field of bioactive phytochemicals. Gallic acid, a natural polyphenolic compound, exists freely as well as in polymeric forms. The anti-cancer properties of gallic acid are indomitable by a variety of cellular pathways such as induction of programmed cell death, cell cycle apprehension, reticence of vasculature and tumor migration, and inflammation. Furthermore, gallic acid is found to show synergism with other existing chemotherapeutic drugs. Therefore, the antineoplastic role of gallic acid suggests its promising therapeutic candidature in the near future. The present review describes all these aspects of gallic acid at a single platform. In addition nanotechnology-mediated approaches are also discussed to enhance bioavailability and therapeutic efficacy.

Gallic Acid: A Potential Anti-Cancer Agent

Cancer is one of the most devastating diseases worldwide and definitive therapeutics for treating cancer are not yet available despite extensive research efforts. The key challenges include limiting factors connected with traditional chemotherapeutics, primarily drug resistance, low response rates, and adverse side-effects. Therefore, there is a high demand for novel anti-cancer drugs that are both potent and safe for cancer prevention and treatment. Gallic acid (GA), a natural botanic phenolic compound, can mediate various therapeutic properties that are involved in anti-inflammation, anti-obesity, and anti-cancer activities. More recently, GA has been shown to exert anti-cancer activities via several biological pathways that include migration, metastasis, apoptosis, cell cycle arrest, angiogenesis, and oncogene expression. This review discusses two aspects, one is the anti-cancer potential of GA against different types of cancer and the underlying molecular mechanisms, the other is the bibliometric analysis of GA in cancer and tumor research. The results indicated that lung cancer, prostate cancer, stomach cancer, and colon adenocarcinoma may become a hot topic in further research. Overall, this review provides evidence that GA represents a promising novel, potent, and safe anti-cancer drug candidate for treating cancer.

Antiaging Properties of the Ethanol Fractions of Clove (Syzygium aromaticum L.) Bud and Leaf at the Cellular Levels: Study in Yeast Schizosaccharomyces pombe

The exposure of reactive oxygen species is one of the aging triggers at cellular level. The antioxidants have been used as strategic efforts in overcoming the accumulation of ROS. Previous research using crude extracts of clove bud and leaves showed its potential as an antioxidant agent. However, no data were available regarding the antioxidant and antiaging activities of subsequent fractions of clove extracts. Therefore, this study aimed to analyze the antioxidant and antiaging activities of the n-hexane and ethanol fractions from clove bud and leaves. Antioxidant and antiaging activities were tested at the cellular level using the yeast model Schizosaccharomyces pombe. The highest flavonoid content was shown by clove leaf n-hexane fraction (25.6 mgQE·g−1). However, ethanol fraction of clove bud (FEB) showed the highest antioxidant activity based on TBA and antiglycation assays. FEB (8 μg·mL−1) and leaf ethanol fraction (FEL) (10 μg·mL−1) were able to induce yeast tolerance against oxidative stress. In addition, FEB could induce mitochondrial activity and delay the G1 phase of the cell cycle. FEB was found to be rich in gallic acid and (15Z)-9,12,13-trihydroxy-15-octadecenoic. Based on the data, FEB shows the potential antiaging activity, which is promising for further development as biopharmaceutical product formulations.

Therapeutic Effects of Gallic Acid in Regulating Senescence and Diabetes; an In Vitro Study

Gallic acid (GA), a plant-derived ubiquitous secondary polyphenol metabolite, can be a useful dietary supplement. This in vitro study's primary purpose was to assess the anti-aging properties of GA using rat embryonic fibroblast (REF) cells, antidiabetic effects via pancreatic islet cells, and finally, elucidating the molecular mechanisms of this natural compound. REF and islet cells were isolated from fetuses and pancreas of rats, respectively. Then, several senescence-associated molecular and biochemical parameters, along with antidiabetic markers, were investigated. GA caused a significant decrease in the β-galactosidase activity and reduced inflammatory cytokines and oxidative stress markers in REF cells. GA reduced the G0/G1 phase in senescent REF cells that led cells to G2/M. Besides, GA improved the function of the β cells. Flow cytometry and spectrophotometric analysis showed that it reduces apoptosis via inhibiting caspase-9 activity. Taken together, based on the present findings, this polyphenol metabolite at low doses regulates different pathways of senescence and diabetes through its antioxidative stress potential and modulation of mitochondrial complexes activities.

Effect of Gallic acid in potentiating chemotherapeutic effect of Paclitaxel in HeLa cervical cancer cells

Background

Cervical cancer is the fourth most common cancer affecting women worldwide. Paclitaxel/Carboplatin is one of the most commonly prescribed regimens in cervical cancer treatment. Although chemotherapeutic drugs are very effective, severe side effects and development of drug resistance limits the use of these drugs. The use of natural products with anticancer activity may help to partially overcome these issues.

Methods

In the present study, we investigated the ability of Gallic acid, to potentiate the anti-cancer effects of Paclitaxel, Carboplatin and Paclitaxel/Carboplatin combination in human HeLa cells by performing MTT assay, cell cycle analysis and RT-PCR assay and Western blotting for some apoptotic markers.

Results

Our results revealed that the highest cytotoxic effect, the highest induction of apoptosis and significant elevation in P53 and Caspase 3 levels was seen in Paclitaxel/Gallic acid combination.

Conclusion

These results indicate that Gallic acid potentiates Paclitaxel effect and that Paclitaxel/Gallic acid combination could represent a promising alternative with lower side effects-for Paclitaxel/Carboplatin combination in treatment of cervical cancer treatment.

Enhancing the Anticancer Activity of Antrodia cinnamomea in Hepatocellular Carcinoma Cells via Cocultivation With Ginger: The Impact on Cancer Cell Survival Pathways

Antrodia cinnamomea (AC) is a medicinal fungal species that has been widely used traditionally in Taiwan for the treatment of diverse health-related conditions including cancer. It possesses potent anti-inflammatory and antioxidant properties in addition to its ability to promote cancer cell death in several human tumors. Our aim was to improve the anticancer activity of AC in hepatocellular carcinoma (HCC) through its cocultivation with ginger aiming at tuning the active ingredients. HCC cell lines, Huh-7 and HepG2 were used to study the in vitro anticancer activity of the ethanolic extracts of AC (EAC) alone or after the cocultivation in presence of ginger (EACG). The results indicated that the cocultivation of AC with ginger significantly induced the production of important triterpenoids and EACG was significantly more potent than EAC in targeting HCC cell lines. EACG effectively inhibited cancer cells growth via the induction of cell cycle arrest at G2/M phase and induction of apoptosis in Huh-7 and HepG2 cells as indicated by MTT assay, cell cycle analysis, Annexin V assay, and the activation of caspase-3. In addition, EACG modulated cyclin proteins expression and mitogen-activated protein kinase (MAPK) signaling pathways in favor of the inhibition of cancer cell survival. Taken together, the current study highlights an evidence that EACG is superior to EAC in targeting cancer cell survival and inducing apoptotic cell death in HCC. These findings support that EACG formula can serve as a potential candidate for HCC adjuvant therapy.

HDAC inhibition as a treatment concept to combat temsirolimus-resistant bladder cancer cells

Introduction

Although the mechanistic target of rapamycin (mTOR) might be a promising molecular target to treat advanced bladder cancer, resistance develops under chronic exposure to an mTOR inhibitor (everolimus, temsirolimus). Based on earlier studies, we proposed that histone deacetylase (HDAC) blockade might circumvent resistance and investigated whether HDAC inhibition has an impact on growth of bladder cancer cells with acquired resistance towards temsirolimus.

Results

The HDAC inhibitor valproic acid (VPA) significantly inhibited growth, proliferation and caused G0/G1 phase arrest in RT112^res and UMUC-3^res. cdk1, cyclin B, cdk2, cyclin A and Skp1 p19 were down-regulated, p27 was elevated. Akt-mTOR signaling was deactivated, whereas acetylation of histone H3 and H4 in RT112^res and UMUC-3^res increased in the presence of VPA. Knocking down cdk2 or cyclin A resulted in a significant growth blockade of RT112^res and UMUC-3^res.

Materials And Methods

Parental (par) and resistant (res) RT112 and UMUC-3 cells were exposed to the HDAC inhibitor VPA. Tumor cell growth, proliferation, cell cycling and expression of cell cycle regulating proteins were then evaluated. siRNA blockade was used to investigate the functional impact of the proteins.

Conclusions

HDAC inhibition induced a strong response of temsirolimus-resistant bladder cancer cells. Therefore, the temsirolimus-VPA-combination might be an innovative strategy for bladder cancer treatment.

Gallic acid inhibits bladder cancer cell proliferation and migration via regulating fatty acid synthase (FAS)

Bladder cancer is known as the world’s ninth most prevalent cancer in 2012. New cytotoxic drugs have created considerable progress in the treatment. Gallic acid (GA) has been shown to inhibit carcinogenesis in animal models and various cancer cell lines. The aim of the present study was to evaluate the effect of GA on proliferation and migration inhibition of a bladder cancer cell line. The results showed that GA inhibited fatty acid synthase (FAS) activity and increased ER alpha level of TSGH-8301 bladder cancer cell. GA regulated the cell proliferation via the PI3K/AKT and MAPK/ERK pathway. Immunoprecipitation assay demonstrated that GA decreased Skp2 protein level and attenuated Skp2-p27 association. It was suggested that GA acted upstream of the proteasome to control p27 levels and ultimately inhibited G2/M phase transition. Further, transwell chambers assay showed that GA suppressed bladder cancer cell invasion and migration through p-AKT/MMP-2 signaling pathway. The finding indicated that GA inhibited TSGH-8301 bladder cancer cell growth, invasion and migration through inhibition of fatty acid synthase.

Inhibition of l-type amino acid transporter 1 activity as a new therapeutic target for cholangiocarcinoma treatment

Unlike normal cells, cancer cells undergo unlimited growth and multiplication, causing them to require massive amounts of amino acid to support their continuous metabolism. Among the amino acid transporters expressed on the plasma membrane, l-type amino acid transporter-1, a Na⁺-independent neutral amino acid transporter, is highly expressed in many types of human cancer including cholangiocarcinoma. Our previous study reported that l-type amino acid transporter-1 and its co-functional protein CD98 were highly expressed and implicated in cholangiocarcinoma progression and carcinogenesis. Therefore, this study determined the effect of JPH203, a selective inhibitor of l-type amino acid transporter-1 activity, on cholangiocarcinoma cell inhibition both in vitro and in vivo. JPH203 dramatically suppressed [¹⁴C]l-leucine uptake as well as cell growth in cholangiocarcinoma cell lines along with altering the expression of l-type amino acid transporter-1 and CD98 in response to amino acid depletion. We also demonstrated that JPH203 induced both G2/M and G0/G1 cell cycle arrest, as well as reduced the S phase accompanied by altered expression of the proteins in cell cycle progression: cyclin D1, CDK4, and CDK6. There was also cell cycle arrest of the related proteins, P21 and P27, in KKU-055 and KKU-213 cholangiocarcinoma cells. Apoptosis induction, detected by an increase in trypan blue-stained cells along with a cleaved caspase-3/caspase-3 ratio, occurred in JPH203-treated cholangiocarcinoma cells at the highest concentration tested (100 µM). As expected, daily intravenous administration of JPH203 (12.5 and 25 mg/kg) significantly inhibited tumor growth in KKU-213 cholangiocarcinoma cell xenografts in the nude mice model in a dose-dependent manner with no statistically significant change in the animal's body weight and with no differences in the histology and appearance of the internal organs compared with the control group. Our study demonstrates that suppression of l-type amino acid transporter-1 activity using JPH203 might be used as a new therapeutic strategy for cholangiocarcinoma treatment.

Antiproliferative and apoptotic effect of Morus nigra extract on human prostate cancer cells

Background: Morus nigra L. belongs to the family Moraceae and is frequently used in traditional medicine. Numerous studies have investigated the antiproliferative effects of various extracts of different Morus species, but studies involving the in vitro cytotoxic effect of M. nigra extract are very limited. The purpose of this study was to evaluate the phenolic composition and antioxidant activity of dimethyl sulfoxide extract of M. nigra (DEM) and to investigate, for the first time, the probable cytotoxic effect in human prostate adenocarcinoma (PC-3) cells together with the mechanism involved. Methods: Total polyphenolic contents (TPC), ferric reducing antioxidant power (FRAP) and phenolic compounds of DEM were evaluated using spectrophotometric procedures and HPLC. The cytotoxic effect of DEM on PC-3 cells was revealed using the MTT assay. Mechanisms involved in the cytotoxic effect of DEM on PC-3 cells were then investigated in terms of apoptosis, mitochondrial membrane potential and cell cycle using flow cytometry, while caspase activity was investigated using luminometric analysis. Results: TPC and FRAP values were 20.7 ± 0.3 mg gallic acid equivalents and 48.8 ± 1.6 mg trolox equivalents per g sample, respectively. Ascorbic acid and chlorogenic acid were the major phenolic compounds detected at HPLC analysis. DEM arrested the cell cycle of PC-3 cells at the G₁ phase, induced apoptosis via increased caspase activity and reduced mitochondrial membrane potential. Conclusions: Our results indicate that M. nigra may be a novel candidate for the development of new natural product based therapeutic agents against prostate cancer.

Anti-tumor effect of Radix Paeoniae Rubra extract on mice bladder tumors using intravesical therapy

Radix Paeoniae Rubra (RPR) is the dried root of Paeonia lactiflora Pallas and Paeonia veitchii Lynch, and is a herbal medicine that is widely used in traditional Chinese medicine for the treatment of blood-heat and blood-stasis syndrome, similarly to Cortex Moutan. The present study identified the same three components in RPR and Cortex Moutan extracts. In addition, it has been reported that RPR has an anti-cancer effect. Bladder cancer is the seventh most common type of cancer worldwide. Due to the high recurrence rate, identifying novel drugs for bladder cancer therapy is essential. In the present study, RPR extract was evaluated as a bladder cancer therapy in vitro and in vivo. The present results revealed that RPR extract reduced the cell viability of bladder cancer cells with a half maximal inhibitory concentration of 1-3 mg/ml, and had an extremely low cytotoxic effect on normal urothelial cells. Additionally, RPR decreased certain cell cycle populations, predominantly cells in the G1 phase, and caused a clear sub-G increase. In a mouse orthotopic bladder tumor model, intravesical application of RPR extract decreased the bladder tumor size without altering the blood biochemical parameters of the mice. In summary, the present results demonstrate the anti-proliferative properties of RPR extract on bladder cancer cells, and its anti-bladder tumor effect in vivo. Compared to Cortex Moutan extract, RPR extract may provide a more effective alternative therapeutic strategy for the intravesical therapy of superficial bladder cancer.

Tousled kinase activator, gallic acid, promotes homologous recombinational repair and suppresses radiation cytotoxicity in salivary gland cells

Accidental or medical radiation exposure of the salivary glands can gravely impact oral health. Previous studies have shown the importance of Tousled-like kinase 1 (TLK1) and its alternate start variant TLK1B in cell survival against genotoxic stresses. Through a high-throughput library screening of natural compounds, the phenolic phytochemical, gallic acid (GA), was identified as a modulator of TLK1/1B. This small molecule possesses anti-oxidant and free radical scavenging properties, but in this study, we report that in vitro it promotes survival of human salivary acinar cells, NS-SV-AC, through repair of ionizing radiation damage. Irradiated cells treated with GA show improved clonogenic survival compared to untreated controls. And, analyses of DNA repair kinetics by alkaline single-cell gel electrophoresis and γ-H2AX foci immunofluorescence indicate rapid resolution of DNA breaks in drug-treated cells. Study of DR-GFP transgene repair indicates GA facilitates homologous recombinational repair to establish a functional GFP gene. In contrast, inactivation of TLK1 or its shRNA knockdown suppressed resolution of radiation-induced DNA tails in NS-SV-AC, and homology directed repair in DR-GFP cells. Consistent with our results in culture, animals treated with GA after exposure to fractionated radiation showed better preservation of salivary function compared to saline-treated animals. Our results suggest that GA-mediated transient modulation of TLK1 activity promotes DNA repair and suppresses radiation cytoxicity in salivary gland cells.

Gallic acid induces mitotic catastrophe and inhibits centrosomal clustering in HeLa cells

Cancer cells divide rapidly, providing medical targets for anticancer agents. The polyphenolic gallic acid (GA) is known to be toxic for certain cancer cells. However, the cellular mode of action has not been elucidated. Therefore, the current study addressed a potential effect of GA on the mitosis of cancer cells. GA inhibited viability of HeLa cells in a dose-dependent and time-dependent manner. We could show, using fluorescence-activated cell sorting (FACS), that this inhibition was accompanied by elevated frequency of cells arrested at the G2/M transition. This cell-cycle arrest was accompanied by mitotic catastrophe, and formation of cells with multiple nuclei. These aberrations were preceded by impaired centrosomal clustering. We arrive at a model of action, where GA inhibits the progression of the cell cycle at the G2/M phase by impairing centrosomal clustering which will stimulate mitotic catastrophe. Thus, GA has potential as compound against cervical cancer.

Gallic acid: prospects and molecular mechanisms of its anticancer activity

Gallic acid (GA) is a phenolic acid found in many dietary substances. It is a natural compound found in gallnuts, sumac, witch-hazel, clove, tealeaves, oak bark, sundew and other plants. Edibles like blackberry, hot chocolate, common walnut and Indian gooseberry contain GA.

Gallic acid: a versatile antioxidant with promising therapeutic and industrial applications

Oxidative stress, a result of an overproduction and accumulation of free radicals, is the leading cause of several degenerative diseases such as cancer, atherosclerosis, cardiovascular diseases, ageing and inflammatory diseases.

Proteomic study reveals a co-occurrence of gallic acid-induced apoptosis and glycolysis in B16F10 melanoma cells

Gallic acid (GA) has long been associated with a wide range of biological activities. In this study, its antitumor effect against B16F10 melanoma cells was demonstrated by MTT assay, cell migration assay, wound-healing assay, and flow cytometric analysis. GA with a concentration >200 μM shows apoptotic activity toward B16F10 cells. According to Western blotting data, overexpressions of cleaved forms of caspase-9, caspase-3, and PARP-1 and pro-apoptotic Bax and Bad, accompanied by underexpressed anti-apoptotic Bcl-2 and Bcl-xL indicate that GA induces B16F10 cell apoptosis via mitochondrial pathway. The 2-DE based comparative proteomics was further employed in B16F10 cells with and without GA treatment for a large-scale protein expression profiling. A total of 41 differential protein spots were quantified, and their identities were characterized using LC-MS/MS analysis and database matching. In addition to some regulated proteins that were associated with apoptosis, interestingly, some identified proteins involved in glycolysis such as glucokinase, α-enolase, aldolase, pyruvate kinase, and GAPDH were simultaneously up-regulated, which reveals that the GA-induced cellular apoptosis in B16 melanoma cells is associated with metabolic glycolysis.

Can selenium be a modifier of cancer risk in CHEK2 mutation carriers?

Selenium is an essential trace element for humans, playing an important role in various major metabolic pathways. Selenium helps to protect the body from the poisonous effects of heavy metals and other harmful substances. Medical studies have provided evidence of selenium supplementation in preventing certain cancers. Low and too high selenium (Se) status correlates with increased risk of e.g. lung, larynx, colorectal and prostate cancers. A higher level of selenium and supplementation with selenium has been shown to be associated with substantially reduced cancer mortality. Selenium exerts its biological roles through selenoproteins, which are involved in oxidoreductions, redox signalling, antioxidant defence, thyroid hormone metabolism and immune responses. Checkpoint kinase 2 (CHEK2) is an important signal transducer of cellular responses to DNA damage and acts as a tumour suppressor gene. Mutations in the CHEK2 gene have been shown to be associated with increased risks of several cancers. Four common mutations in CHEK2 gene (1100delC, IVS2+1G>A, del5395 and I157T) have been identified in the Polish population. Studies have provided evidence that CHEK2-truncating and/or missense mutations are associated with increased risk of breast, prostate, thyroid, colon and kidney cancers. The variability in penetrance and cancer expression in CHEK2 mutation carriers can probably be explained by the influence of other genetic or environmental factors. One of the possible candidates is Se, which together with genetic variations in selenoprotein genes may influence susceptibility to cancer risk.

Gallic acid provokes DNA damage and suppresses DNA repair gene expression in human prostate cancer PC-3 cells

Our earlier studies have demonstrated that gallic acid (GA) induced cytotoxic effects including induction of apoptosis and DNA damage and inhibited the cell migration and invasion in human cancer cells. However, GA-affected DNA damage and repair gene expressions in human prostate cancer cells are still unclear. In this study, we investigated whether or not GA induces DNA damage and inhibits DNA repair gene expression in a human prostate cancer cell line (PC-3). The results from flow cytometric assay indicated that GA decreased the percentage of viable PC-3 cells in a dose- and time-dependent manner. PC-3 cells after exposure to different doses (50, 100, and 200 μM) of GA and various periods of time (12, 24, and 48 h) led to a longer DNA migration smear (comet tail) occurred based on the single cell gel electrophoresis (comet assay). These observations indicated that GA-induced DNA damage in PC-3 cells, which also confirmed by 4,6-diamidino-2-phenylindole dihydrochloride staining and DNA agarose gel electrophoresis. Alternatively, results from real-time polymerase chain reaction assay also indicated that GA inhibited ataxia telangiectasia mutated, ataxia-telangiectasia and Rad3-related, O⁶-methylguanine-DNA methyltransferase, DNA-dependent serine/threonine protein kinase, and p53 mRNA expressions in PC-3 cells. Taken together, the present study showed that GA caused DNA damage and inhibited DNA repair genes as well as both effects may be the critical factors for GA-inhibited growth of PC-3 cells in vitro.

Syringic acid from Tamarix aucheriana possesses antimitogenic and chemo-sensitizing activities in human colorectal cancer cells

CONTEXT

For its variety of biological activities, Tamarix aucheriana (Decne.) Baum. (Tamaricaceae) has an extensive history as a traditional Arab medicine.

OBJECTIVES

Antimitogenic and chemo-sensitizing activities of syringic acid (SA) were studied against human colorectal cancer.

MATERIALS AND METHODS

Chromatographic and spectral data were used for the isolation and identification of SA. MTT, flow cytometry, in vitro invasion and angiogenesis assays, fluoremetry, ELISA and Real Time qPCR were used to test antimitogenic and chemo-sensitizing activities of SA, cell cycle, apoptosis, proteasome and NFκB-DNA-binding activities, cancer cell invasion and angiogenesis, and expression of cell cycle/apoptosis-related genes.

RESULTS

SA showed a time- and dose-dependent (IC₅₀ = 0.95-1.2 mg mL⁻¹) antimitogenic effect against cancer cells with little cytotoxicity on normal fibroblasts (≤20%). SA-altered cell cycle (S/G2-M or G1/G2-M phases) in a time-dependent manner, induced apoptosis, inhibited DNA-binding activity of NFκB (p ≤ 0.0001), chymotrypsin-like/PGPH (peptidyl-glutamyl peptide-hydrolyzing) (p ≤ 0.0001) and the trypsin-like (p ≤ 0.002) activities of 26S proteasome and angiogenesis. SA also differentially sensitized cancer cells to standard chemotherapies with a marked increase in their sensitivity to camptothecin (500-fold), 5FU (20,000-fold), doxorubicin (210-fold), taxol (3134-fold), vinblastine (1000-fold), vincristine (130-fold) and amsacrine (107-fold) compared to standard drugs alone.

DISCUSSION

SA exerted its chemotherapeutic and chemo-sensitizing effects through an array of mechanisms including cell-cycle arrest, apoptosis induction, inhibition of cell proliferation, cell migration, angiogenesis, NFκB DNA-binding and proteasome activities.

CONCLUSION

These results demonstrate the potential of SA as an antimitogenic and chemo-sensitizing agent for human colorectal cancer.

Gallic acid induces the apoptosis of human osteosarcoma cells in vitro and in vivo via the regulation of mitogen-activated protein kinase pathways

To examine the antitumor effects of gallic acid (GA) on osteosarcoma, two human osteosarcoma cell lines U-2OS and MNNG/HOS were treated by GA and subjected to cell proliferation and apoptosis assays. In addition, MNNG/HOS xenograft tumors were established in nude BALB/c mice to evaluate the anticancer capacity of GA in vivo. The results showed that GA inhibited the proliferation and induced the apoptosis of osteosarcoma cells, accompanied by the upregulation of p-38 activation and the downregulation of c-Jun N-terminal kinase (JNK) and extracellular signal regulated kinase (ERK1/2) activation. Additionally, p38 MAPK inhibitor abrogated GA-induced growth inhibition of osteosarcoma cells, whereas JNK or ERK1/2 inhibitors sensitized osteosarcoma cells to GA-induced growth inhibition. In vivo studies further showed that GA administration decreased xenograft tumor growth in a dose-dependent manner. Immunohistochemistry analysis demonstrated the downregulation of PCNA and CD31 expression and upregulation of apoptosis in MNNG/HOS tumor tissues following GA treatment. This study demonstrates the antitumor efficacy of GA for osteosarcoma that is mediated by the modulation of cell proliferation, apoptosis, and angiogenesis. Our findings suggest that GA could be a potent agent for osteosarcoma intervention.

Paeonia lactiflora Pall inhibits bladder cancer growth involving phosphorylation of Chk2 in vitro and in vivo

ETHNOPHARMACOLOGICAL RELEVANCE

Extracts of Paeonia lactiflora Pall (RPA), a traditional Chinese medicines has been shown to treat cancers.

AIM OF THE STUDY

The purpose of this study is to evaluate the anticancer effect of RPA in urinary bladder carcinoma in vitro and in vivo.

MATERIALS AND METHODS

The cell viability was analyzed with DAPI. Flow cytometry and Western blot were used to study the apoptosis and cell cycle related mechanism. A rat model of bladder cancer was induced by N-butyl-N-(4-hydroxybutyl) nitrosamine (OH-BBN). Tumors were analyzed with immunohistochemical analysis.

RESULTS

Our data suggested that RPA inhibits growth of bladder cancer via induction of apoptosis and cell cycle arrest. Treatment of TSGH-8301 cells with RPA resulted in G2-M phase arrest that was associated with a marked decline in protein levels of cdc2, cyclin B1, cell division cycle 25B (Cdc25B) and Cdc25C. We also reported that RPA-mediated growth inhibition of TSGH-8301 cells was correlated with activation of checkpoint kinase 2 (Chk2). Herein, we further evaluated urinary bladder cancer using a model of bladder cancer induced by OH-BBN. Analysis of tumors from RPA-treated rats showed significant decrease in the expression of Bcl2, cyclin D1, and PCNA, and increase in the expression of p-Chk2 (Thr-68), Bax, and Cip1/p21.

CONCLUSION

Our data provide the experimental evidence that RPA could modulate apoptosis in models of bladder cancer.