Potential Candidate For Anticancer Therapy Research Articles

Acarbose a promising inhibitor of 17®-hydroxysteroid dehydrogenase type 1 as a potential candidate for anticancer therapy

Acarbose a promising inhibitor of 17®-hydroxysteroid dehydrogenase type 1 as a potential candidate for anticancer therapy

Inhibition of Wnt Signaling by Atovaquone Inhibits Gastric Cancer and Enhances Chemotherapy Effectiveness Through Activation of Casein Kinase 1α

Abnormal activation of the Wnt/β-catenin signaling pathway is a driving force behind the progression of gastric cancer. Atovaquone, known as an antimalarial drug, has emerged as a potential candidate for anti-cancer therapy. This study investigated atovaquone’s effects on gastric cancer and its underlying mechanisms. Using gastric cancer cell lines, we found that atovaquone, at concentrations relevant to clinical use, significantly reduced their viability. Notably, atovaquone exhibited a lower effectiveness in reducing the viability of normal gastric cells compared to gastric cancer cells. We further demonstrated that atovaquone inhibited gastric cancer growth and colony formation. Mechanism studies revealed that atovaquone inhibited mitochondrial respiration and induced oxidative stress. Experiments using ρ0 cells, deficient in mitochondrial respiration, indicated a slightly weaker effect of atovaquone on inducing apoptosis compared to wildtype cells. Atovaquone increased phosphorylated β-catenin at Ser45 and Ser33/37/Thr41, elevated Axin, and reduced β-catenin. The inhibitory effects of atovaquone on β-catenin were reversed upon depletion of CK1α. Furthermore, the combination of atovaquone with paclitaxel suppressed gastric cancer growth and improved overall survival in mice. Given that atovaquone is already approved for clinical use, these findings suggest its potential as a valuable addition to the drug arsenal available for treating gastric cancer.

Exploring the impact of trifluoromethyl (-CF3) functional group on the anti-cancer activity of isoxazole-based molecules: design, synthesis, biological evaluation and molecular docking analysis.

Herein we report the design and synthesis of a series of fully-substituted 4-(trifluoromethyl)isoxazoles and evaluation of their anti-cancer activities against MCF-7, 4T1 and PC-3 cell lines as a proof of concept study. 4-(Trifluoromethyl)isoxazole is a synthetically challenging class of molecules and very few synthetic methods have been developed so far and all of them suffered from several serious limitations. Recently we developed a novel, metal-free, and general synthetic strategy to access synthetically challenging 4-(trifluoromethyl)isoxazoles starting from readily available chalcones using cheap CF3SO2Na as the source of the -CF3 group and multitasking t BuONO as an oxidant as well as the source of N and O and thus we have overcome the limitations of the previous methods. Based on the structure of an isoxazole-based anti-cancer agent, 3-(3,4-dimethoxyphenyl)-5-(thiophen-2-yl)isoxazole 14, we designed a set of 4-(trifluoromethyl)isoxazoles for synthesis and further anti-cancer evaluation. Among various molecules, 3-(3,4-dimethoxyphenyl)-5-(thiophen-2-yl)-4-(trifluoromethyl)isoxazole 2g (IC50 = 2.63 μM) and 3-(thiophen-2-yl)-5-(4-(thiophen-2-yl)-1H-pyrrol-3-yl)-4-(trifluoromethyl)isoxazole 5 (IC50 = 3.09 μM) exhibited the best anti-cancer activity against the human breast cancer cell-lines (MCF-7), 2g being the lead molecule among all. Interestingly, 2g is found to be almost 8 times more active compared to its non-trifluoromethylated analogue, i.e., 3-(3,4-dimethoxyphenyl)-5-(thiophen-2-yl)isoxazole 14 (IC50 = 19.72 μM) which revealed the importance of a 'CF3' moiety in enhancing the anti-cancer activity of 14. Further studies such as apoptosis induction, cell cycle analysis, and nuclear staining revealed an apoptotic cell death mechanism. The in silico molecular docking, induced fit analysis, and ADME studies further supported the effect of a -CF3 moiety on the enhancement of anti-cancer activity of isoxazole-based anti-cancer molecules. Further exploration of the biodistribution and therapeutic efficacy of lead 2gin vivo holds significant promise, positioning it as a potential candidate for anticancer therapy.

Fisetin in Cancer: Attributes, Developmental Aspects, and Nanotherapeutics.

Cancer is one of the major causes of mortality, globally. Cancerous cells invade normal cells and metastasize to distant sites with the help of the lymphatic system. There are several mechanisms involved in the development and progression of cancer. Several treatment strategies including the use of phytoconstituents have evolved and been practiced for better therapeutic outcomes against cancer. Fisetin is one such naturally derived flavone that offers numerous pharmacological benefits, i.e., antioxidant, anti-inflammatory, antiangiogenic, and anticancer properties. It inhibits the rapid growth, invasiveness, and metastasis of tumors by hindering the multiplication of cancer cells, and prompts apoptosis by avoiding cell division related to actuation of caspase-9 and caspase-8. However, its poor bioavailability associated with its extreme hydrophobicity hampers its clinical utility. The issues related to fisetin delivery can be addressed by adapting to the developmental aspects of nanomedicines, such as formulating it into lipid or polymer-based systems, including nanocochleates and liposomes. This review aims to provide in-depth information regarding fisetin as a potential candidate for anticancer therapy, its properties and various formulation strategies.

Antitumor and Cytotoxic Protein Component from Aporrectodea longa: Purification, and Characterization Studies

Abstract: Background: Cancer, a metabolic disorder with multifactorial input, is the most complex human disease to study and find a cure. Over several decades, massive research effort leads to a better understanding molecular biology of cancer and its progression. Plants and animals both were explored for novel anti-tumor agents, and enzyme-based drugs have shown significant results. These animals evolved with an enzyme with promiscuous nature capable of catalyzing multiple biochemical reactions. Enzymes are an integral part of animal physiology and are reported excellent sources of the drug. Objectives: The study aimed to isolate, purify and characterize the protein component from Aporrectodea longa for anti-cancer potential. Materials and Methods: A. longa species earthworms were collected and processed for the extraction of total protein content. The anti-tumor protein component was purified via salt precipitation, charge-based purification, and sizebased purification. SDS-PAGE was used to investigate molecular weight information. The anti-tumor activity was evaluated using different cell lines, including MCF 7, Hep G2, and HT 29 with Cisplatin, 5-fluorouracil, and tamoxifen as a standard anti-cancer drug. Results: The isolated and purified protein fraction had shown proteolytic activity against casein and fibrinogen. Protein fraction represents a serine protease and average molecular weight of nearly 42kDa. The result shows protein component possesses excellent antitumor activity analyzed by MTT assay. Conclusion: Anti-tumor activity of isolated and purified protein fraction from A. longa may serve as a potential candidate for anti-cancer therapy. However, molecular studies are required to explore the precise mechanism of action of candidate protein. Key words: Antineoplastic agents, Cytotoxic activity, MTT assay, Chromatography, Cell lines, Protein/enzyme.

A cyclic peptide retards the proliferation of DU145 prostate cancer cells in vitro and in vivo through inhibition of FGFR2.

In malignancies, fibroblast growth factor receptors (FGFRs) signaling is reinforced through overexpression of fibroblast growth factors (FGFs) or their receptors. FGFR2 has been proposed as a target for cancer therapy, because both the expression and activation of FGFR2 are boosted in various malignant carcinomas. Although several chemicals have been designed against FGFR2, they did not exhibit enough specificity and might bring potential accumulated toxicity. In this study, we developed an epitope peptide (P5) and its cyclic derivative (DcP5) based on the structure of FGF2 to limit the activation of FGFR2. The anticancer activities of P5 and DcP5 were examined in vitro and in vivo. Our results demonstrated that P5 significantly inhibited the cell proliferation in FGFR2‐dependent manner in DU145 cells and retarded tumor growth in DU145 xenograft model with negligible toxicity toward normal organs. Further investigations found that the Gln4 and Glu6 residues of P5 bind to FGFR2 to abolish its activation. Moreover, we developed the P5 cyclic derivative, DcP5, which achieved reinforced stability and anticancer activity in vivo. Our findings suggest P5 and its cyclic derivative DcP5 as potential candidates for anticancer therapy.

Synthesis and Cytotoxic Analysis of Novel Myrtenyl Grafted Pseudo-Peptides Revealed Potential Candidates for Anticancer Therapy.

Myrtenal is a natural monoterpene isolated from essential oils of several plants and their derivates have shown to have several biological properties including cytotoxicity. The cytotoxic activity of these derivates are being investigated for their antitumor effect leading to the development of potential anticancer agents. In this study, novels Myrtenyl grafted pseudo-peptides were designed, synthesized and functionally characterized as possible therapeutic agents for cancer treatment. Thirteen novel Myrtenyl grafted pseudo-peptides were prepared in high atom economy and efficiency by a classic Ugi-4CR and sequential post-modification. Their structures were confirmed by NMR, and ESI-MS, and its cytotoxic activity was evaluated in three cancer cell lines and primary CD4+ T cells at different proliferative cycles. Our results revealed that some of these compounds showed significant cytotoxicity against human gastric, breast and colon adenocarcinoma cells lines, but not against human dermal fibroblast cell line. Moreover, from the thirteen novel myrtenyl synthesized the compound (1R,5S)-N-{[1-(3-chlorophenyl)-1H-1,2,3-triazol-4-yl]methyl}-N-[2-(cyclohexylamino)-2–oxoethyl]-6,6-dimethylbicyclo[3.1.1]hept-2-ene-2-carboxamide (3b) proved to be the best candidate in terms of acceptable EC50, and Emax values in cancer cell lines and at inducing cytotoxicity in CD4+ T cells undergoing active proliferation, without affecting non-proliferating T cells. Overall, the synthesis and characterization of our Myrtenyl derivates revealed novel potential anticancer candidates with selective cytotoxic activity.

Emerging mycotoxins in botanicals: benefit and risk

Background: Fusarium species are responsible for production of emerging mycotoxins with cyclic hexadepsispeptides structures, like enniatins and beauvericin. Although these mycotoxins have not been regulated yet, their high prevalence in food and feed, as well as their potential toxic effects in humans and animals have made of them a burning issue and a threat to food security. Besides its inophoric properties, these mycotoxins may induce cells damages such as oxidative stress, mitochondrial modifications and the disruption on the cell cycle related to several health adverse effects such as immunotoxicity, genotoxicity, endocrine toxicity and neurotoxicity. Moreover, they showed interesting activity against various microorganisms and insects in several studies, leading to a potential use in pesticide and medicine research, as potential candidates for anticancer therapy. Botanicals can go contaminated by mycotoxins when the harvesting practices or manufacturing conditions are inadequate, which make mandatory their study. Methods: This review explores emerging mycotoxins occurrence in several botanicals forms and discuss their possible prejudicial and beneficial effects. Results: Several researchers have reported mycotoxins occurrence at low incidences and levels in botanicals. Despite emerging mycotoxins toxic effects, beneficial properties have been attributed to these mycotoxins by several authors. These compounds are related to insecticidal activity, antibacterial properties, and antifungal and antiviral activities. Cell organelles or enzyme systems are the targets in its antimicrobial activity. Data collected showed also that emerging mycotoxins are involved in capacity of the multidrug transport protein in human cancer cells modulation and apoptotic cell death induction, several researchers are explaining the possibility to employ them with medicinal purpose. Conclusion: More studies are required to explore enniatins and beauvericin possible applications in medicinal and pesticide research. Furthermore, it is important to highlight that the regulation of emerging mycotoxins in food must be revised and updated. Keywords: anticancer, antimicrobials, beauvericin, cytotoxicity, enniatins, medicinal plants.

Identification of Withaferin A as a Potential Candidate for Anti-Cancer Therapy in Non-Small Cell Lung Cancer.

Low response rate and recurrence are common issues in lung cancer; thus, identifying a potential compound for these patients is essential. Utilizing an in silico screening method, we identified withaferin A (WA), a cell-permeable steroidal lactone initially extracted from Withania somnifera, as a potential anti–lung cancer and anti–lung cancer stem-like cell (CSC) agent. First, we demonstrated that WA exhibited potent cytotoxicity in several lung cancer cells, as evidenced by low IC50 values. WA concurrently induced autophagy and apoptosis and the activation of reactive oxygen species (ROS), which plays an upstream role in mediating WA-elicited effects. The increase in p62 indicated that WA may modulate the autophagy flux followed by apoptosis. In vivo research also demonstrated the anti-tumor effect of WA treatment. We subsequently demonstrated that WA could inhibit the growth of lung CSCs, decrease side population cells, and inhibit lung cancer spheroid-forming capacity, at least through downregulation of mTOR/STAT3 signaling. Furthermore, the combination of WA and chemotherapeutic drugs, including cisplatin and pemetrexed, exerted synergistic effects on the inhibition of epidermal growth factor receptor (EGFR) wild-type lung cancer cell viability. In addition, WA can further enhance the cytotoxic effect of cisplatin in lung CSCs. Therefore, WA alone or in combination with standard chemotherapy is a potential treatment option for EGFR wild-type lung cancer and may decrease the occurrence of cisplatin resistance by inhibiting lung CSCs.

Biotinylated PAMAM G3 dendrimer conjugated with celecoxib and/or Fmoc-l-Leucine and its cytotoxicity for normal and cancer human cell lines

Tumors still remain one of the main causes of mortality due to the lack of effective anti-cancer therapy. Recently it has been shown, that overexpression of inducible cyclooxygenase-2 (COX-2) and decrease of peroxisome proliferator-activated receptor γ (PPARγ) expression accompany many malignances, therefore, it has been proposed, that COX-2 inhibitors and PPARγ agonists are potential candidates for anticancer therapy and their synergistic, antineoplastic action has been described. In the present study a COX-2 inhibitor (celecoxib) and/or PPARγ agonist (Fmoc-l-Leucine) were conjugated with the biotinylated G3 PAMAM dendrimer to form a three different constructs targeted to cells with increased biotin uptake. All conjugates were characterized by the NMR spectroscopy. Investigation of three types of human cells: normal skin fibroblasts (BJ), immortalized keratinocytes (HaCaT) and cancer lines: glioblastoma (U-118 MG) and squamous cell carcinoma (SCC-15) revealed similar biotin labeled ATTO590 accumulation (after 24 h), except for SCC-15 with significantly lower loading. Constitutive expression of COX-2 protein was confirmed in all tested cells with significantly higher levels (2–2.5 times) in both cancer lines.Comparison of cytotoxicity of the new synthetized dendrimers clearly documented the highest cytotoxicity of the G31B16C15L dendrimer conjugated with both drugs (1: 1) as compared with drugs alone and single conjugates. Additive effects of construct with both compounds were shown for fibroblasts and both cancer cell lines in the order BJ > U-118 MG > SCC-15 with IC50 in the range: 0.69, 1.44 and 2.22 μM, respectively and lowest cytotoxicity in HaCaT cells (IC50 = 2.88). Our results showed, that biotinylated G3 PAMAM dendrimers substituted with COX-2 inhibitor, celecoxib, and PPARγ agonist, Fmoc-l-Leucine (1:1) may be a good candidate for local therapy of glioblastoma but not a skin cancer. Since the effect of PPARγ agonists on COX-2 expression vary depending upon the cell type, specificity of used agonist and the presence of other environmental factors, it is necessary to carefully evaluate the response of chosen drugs on the target cells.

Dietary isothiocyanate sulforaphene induces reactive oxygen species, caspase -9, -8, -3-dependent apoptosis and modulates PTEN/PI3Kinase in human cervical cancer cells

Purpose : To investigate the apoptotic activity, cell proliferation inhibition and different signaling protein expressions after treatment with a new isothiocyanate, sulforaphene, in human cervical cancer (HeLa) cells. Methods : Cytotoxicity was analyzed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay after sulforaphene treatment for 3, 6, 12 and 24 h. Apoptosis assay, cell cycle analysis, intracellular oxygen species (ROS) measurement, mitochondrial membrane depolarization and western blot analysis were performed in four time-intervals to explore sulforaphene activity. Results : HeLa cell viability was reduced by sulforaphene dose and time dependently. ROS plays a causative role in sulforaphene induced cytotoxicity and apoptosis during which stimulation of Bax and blocking of Bcl2 were involved. Mitochondrial membrane potential depletion and cytochrome C, AIF modulation suggest mitochondrial pathway for the apoptosis. Activation of caspase -9, -8 and -3 in treated HeLa cells demonstrated caspase-dependent apoptosis by sulforaphene. Again, sulforaphene induced HeLa cell proliferation inhibition was evidenced by cell cycle arrest and PTEN/PI3Kinase modulation. Conclusion : Dietary sulforaphene induces HeLa cell apoptosis by enhancing intracellular ROS levels, thereby activating multiple apoptotic signal cascades. Therefore, sulforaphene is a potential candidate for anticancer therapy. Keywords : Sulforaphene, HeLa cells, Apoptosis, ROS, Caspase activation, PTEN, PI3Kinase

Synthesis, characterization and cytotoxicity of a new palladium(II) complex with a coumarine-derived ligand

The new coumarine derivative, 3-(1-(2-hydroxyethylamino)ethylidene)chroman-2,4--dione, and corresponding palladium(II) complex have been synthesized and characterized by microanalysis, infrared, 1H and 13C NMR spectroscopy. The proposed structure of the complex was confirmed on the basis of the X-ray structural study. The palladium(II) complex decreased viability of L929 mouse fibrosarcoma, U251 human glioma and B16 mouse melanoma cell lines in a dose dependent manner, while its ligand exhibited no significant cytotoxicity. The cytotoxic effect of the complex was comparable to that of cisplatin, and mediated by apoptosis associated with oxidative stress, mitochondrial depolarization and caspase activation. Therefore, our results indicate that newly synthesized palladium(II) complex might be a potential candidate for anticancer therapy.

Preparation of progenin III from total steroidal saponins of Dioscorea nipponica Makino using a crude enzyme from Aspergillus oryzae strain

Progenin III, one of the most active spirostanol saponins, is a potential candidate for anti-cancer therapy due to its strong antitumor activity and low hemolytic activity. However, the concentration of progenin III is extremely low in natural Dioscorea plants. In this paper, the progenin III production from total steroidal saponins of Dioscorea nipponica Makino was studied using the crude enzyme from Aspergillus oryzae DLFCC-38. The crude enzyme converting total steroidal saponins into progenin III was obtained from the A. oryzae DLFCC-38 culture. For enzyme production, the strain was cultured for 72h at 30°C with shaking at 150rpm in 5% (w/v) malt extract medium containing 2% (v/v) extract of D. nipponica as the enzyme inducer. The crude enzyme converted total steroidal saponins into major progenin III with a high yield when the reaction was carried out for 9h at 50°C and pH 5.0 with the 20mg/ml of substrate. In the preparation of progenin III, 117g of crude progenin III was obtained from 160g of substrate, and the crude product was purified with silica gel column to obtain 60.3g progenin III of 93.4% purity.

P02.05 - Pharmacological Stabilization of Commd1 Mediated by CIGB-552 Regulates NF-KB/Oxidative Stress Signaling and Inhibits Lung Cancer Cells Growth

We have demonstrated that a novel peptide designed from an Alanine scanning of the Limulus-derived LALF32-51 region is a potential candidate for anticancer therapy. The peptide L-2 shows antineoplastic effect in a variety of tumor cell lines and its cell-penetrating capacity is an useful property associated. By modification in the primary structure of L-2 we have developed a second-generation peptide (CIGB-552) as anticancer drug. However, the molecular mechanism by which the CIGB-552 exhibits cytotoxic activity in cancer cells remain incompletely defined. In this study, we show that CIGB-552 increases the levels of COMMD1, a protein involved in copper homeostasis, sodium transport and the NF-kB signaling pathway. We found that CIGB-552 induces ubiquitination of RelA and inhibits the anti-apoptotic genes regulated by NF-kB whereas knockdown of COMMD1 blocks this effect. Concomitantly, microarrays profiling of lung cancer cells treated with CIGB-552 identified the expression of many genes involve in the oxidative stress response, cell growth arrest and DNA-damage inducible. Mechanistically, our studies show that CIGB-552 regulates the anti-apoptotic activity of NF-kB and induces an imbalance of the antioxidant defenses, promoting cell cycle arrest and apoptosis in lung cancer cells. Interestingly, the peptides derived from LALF32−51 region were found to bind COMM domain (amino acids 119-190) and, more important, our results provide the first indication that CIGB-552 could regulate the levels of COMMD1 to induce the cell death in cancer cells.

Enzymatic preparation of 20(S, R)-protopanaxadiol by transformation of 20(S, R)-Rg3 from black ginseng

20(S)-protopanaxadiol (PPD(S)) and 20(R)-protopanaxadiol (PPD(R)), the main metabolites of ginsenosides Rg3(S) and Rg3(R) in black ginseng, are potential candidates for anti-cancer therapy due to their pharmacological activities such as anti-tumor properties. In the present study, we report the preparation of PPD(S, R) by a combination of steaming and biotransformation treatments from ginseng. Aspergillus niger was isolated from soil and showed a strong ability to transform Rg3(S, R) into PPD(S, R) with 100% conversion. Furthermore, the enzymatic reactions were analyzed by reversed-phase HPLC, showing the biotransformation pathways: Rg3(S) → Rh2(S) → PPD(S) and Rg3(R) → Rh2(R) → PPD(R), respectively. In addition, 12 ginsenosides including 3 pairs of epimers, namely Rg3(S), Rg3(R), Rh2(S), Rh2(R), PPD(S) and PPD(R), were simultaneously determined by reversed-phase HPLC. Our study may be highly applicable for the preparation of PPD(S) and PPD(R) for medicinal purposes and also for commercial use.

Identification of a novel antitumor peptide based on the screening of an Ala‐library derived from the LALF32–51 region

Novel therapeutic peptides are increasingly making their way into clinical application. The cationic and amphipathic properties of certain peptides allow them to cross biological membranes in a non-disruptive way without apparent toxicity increasing drug bioavailability. By modifying the primary structure of the Limulus-derived LALF(32-51) peptide we designed a novel peptide, L-2, with antineoplastic effect and cell-penetrating capacity. Interestingly, L-2 induced cellular cytotoxicity in a variety of tumor cell lines and systemic injection into immunocompetent and nude mice bearing established solid tumor, resulted in substantial regression of the tumor mass and apoptosis. To isolate the gene transcripts specifically regulated by L-2 in tumor cells, we conducted suppressive subtractive hybridization (SSH) analysis and identified a set of genes involved in biological processes relevant to cancer biology. Our findings describe a novel peptide that modifies the gene expression of the tumor cells and exhibits antitumor effect in vivo, indicating that peptide L-2 is a potential candidate for anticancer therapy.

Efficient Telomerase Inhibition in Human Non-small Cell Lung Cancer Cells by Liposomal Delivery of 2′-O-Methyl-RNA

The antisense oligonucleotide 2′-O-methyl-RNA is a selective telomerase inhibitor targeting the telomerase RNA component and represents a potential candidate for anticancer therapy. The poor cellular uptake of 2′-O-methyl-RNA is a limiting factor that may contribute to the lack of functional efficacy. To improve delivery of 2′-O-methyl- RNA and consequently antitumoral efficiency in human lung cancer cells, we have investigated several transfection reagents. The transfection reagents DOTAP, Mega- Fectin 60, SuperFect, FuGENE 6 and MATra-A were tested for intracellular delivery. A FAM-labeled 2′-O-methyl-RNA was used to assess the intracellular distribution by confocal laser scanning microscopy in A549 human non-small cell lung cancer cells. Telomerase activity was measured using the telomeric repeat amplification protocol. Cell viability after transfection was quantified by the MTT assay. All transfection reagents enhanced 2′-O-methyl-RNA uptake in A549 cells but the cationic lipid reagents DOTAP and MegaFectin 60 were most efficient in the delivery of 2′-O-methyl-RNA resulting in telomerase inhibition. Among both DOTAP exhibited the lowest cytotoxicity. Our experiments show that DOTAP is the most suitable transfection reagent for the delivery of 2′-O-methyl-RNA in human lung cancer cells according to its relatively low cytotoxicity and its ability to promote efficient uptake leading to the inhibition of telomerase.

Anti-cancer activity of highly purified sulfur in immortalized and malignant human oral keratinocytes

Sulfur is commonly used in Asia as an herbal medicine to treat inflammation and cancer, and potent chemopreventive effects have been demonstrated in various in vivo and in vitro models for sulfur-containing compounds found in naturally occurring products. Here, we report the growth inhibitory and apoptosis-related effects of a newly developed highly purified sulfur (HPS) on immortalized human oral keratinocytes (IHOKs) and on oral cancer cells representing two stages of oral cancer (HN4, HN12) based on a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, Western blotting, cell cycle analysis, and nuclear staining. The purity of the sulfur preparation was verified by high-performance liquid chromatography. HPS inhibited the proliferation of immortalized and malignant oral keratinocytes in a dose- and time-dependent manner. FITC-annexin V staining, DNA fragmentation testing, and Hoechst 33258 staining revealed that HPS inhibited cell growth via apoptosis. HPS increased the sub-G1 cell cycle fraction, with decreased expression of cyclins D1, D2, and E and their activating partners cdk2, cdk4, and cdk6, and a concomitant induction of p53 and p21/WAF1. Furthermore, HPS treatment increased the cytosolic level of cytochrome c and resulted in caspase-3 activation; this effect was correlated with Bax up-regulation and Bcl-2 down-regulation. Thus, these data suggest that HPS is a potential candidate for anti-cancer therapy in oral cancer.

Effectiveness of Trichostatin A as a Potential Candidate for Anticancer Therapy in Non–Small-Cell Lung Cancer

A well-known histone deacetylase inhibitor, trichostatin A, was applied to non-small-cell lung cancer cells to determine whether inhibition of histone deacetylase leads to the production of proteins that either arrest tumor cell growth or lead to tumor cell death. Trichostatin A (0.01 to 1.0 micromol/L) was applied to one normal lung fibroblast and four non-small-cell lung cancer lines, and its effect was determined by flow cytometry, annexin-V staining, immunoprecipitation, and Western blot analysis. Trichostatin A demonstrated tenfold greater growth inhibition in all four non-small-cell lung cancer lines compared with normal controls, with a concentration producing 50% inhibition ranging from 0.01 to 0.04 micromol/L for the tumor cell lines and 0.7 micromol/L for the normal lung fibroblast line. Trichostatin A treatment reduced the percentage of cells in S phase (10% to 23%) and increased G1 populations (10% to 40%) as determined by flow cytometry. Both annexin-V binding assay and upregulation of the protein, gelsolin (threefold to tenfold), demonstrated that the tumor cells were apoptotic, whereas normal cells were predominantly in cell cycle arrest. Trichostatin A increased histone H4 acetylation and expression of p21 twofold to 15-fold without significant effect on p16, p27, CDK2, and cyclin D1. Collectively, these data suggest that inhibition of histone deacetylation may provide a valuable approach for lung cancer treatment. We evaluated trichostatin A as a potential candidate for anticancer therapy in non-small-cell lung cancer.

Rho GTPases: potential candidates for anticancer therapy

Low molecular weight Rho GTPases are proteins that, in response to diverse stimuli, control key cellular processes such as cell proliferation, apoptosis, lipid metabolism, cytoarchitecture, adhesion, migration, cell polarity, and transcriptional regulation. The high incidence of overexpression of some members of the Rho family of GTPases in human tumors suggests that these proteins are important in the carcinogenic process, and therefore potential candidates for a therapeutic intervention. In recent years, the characterization of downstream effectors to Rho GTPases has increased our understanding of the general cellular effects that permit aberrant proliferation and motility of tumor cells. In addition, several transcription factors have been identified to play important roles at various levels of Rho-induced tumorigenesis. Accordingly, drugs that specifically alter Rho signaling display antineoplastic properties both at the level of tumor growth and tumor metastasis. In this review, a brief summary of the progress made in understanding the biological functions elicited by Rho GTPases that contribute to tumor biology will be made. In addition, a description of new drugs available targeted to specific elements of Rho signaling with antineoplastic or antimetastatic activity is included.