The use of the MTT assay to study drug resistance in fresh tumour samples

Vetting of New 2,5-Bis (2,2,2-trifluoroethoxy) Phenyl-Linked 1,3-Thiazolidine-4-one Derivatives as AURKA and VEGFR-2 Inhibitor Antiglioma Agents Assisted with In Vitro and In Silico Studies

The bioactivity of 1,3-thiazolidin-4-one derivatives with a 2,5-bis (2,2,2-trifluoroethoxy) phenyl moiety was computationally developed and evaluated. All of the synthesized thiazolidin-4-one derivatives have their chemical structures characterized using a variety of methods, including nuclear magnetic resonance (NMR) (1H and 13C), high-resolution mass spectrometry (HRMS), and Fourier transform infrared (FTIR) radiation. A human glioblastoma cancer cell line (LN229) was used to investigate the purified derivatives' antiglioma cancer efficacy. By using the MTT, colony formation, and tunnel tests, respectively, the in vitro cytotoxic and apoptotic effects of these compounds were assessed. Thiazolidin-4-one derivatives 5b, 5c, and 5e were discovered to have the best efficacy against glioblastoma cells out of all of these compounds. The derivatives 5b, 5c, and 5e were determined to have respective IC50 values of 9.48, 12.16, and 6.43 g/mL. Computation results showed that the bioactivity evaluations of the compounds were quite significant. The bridging -NH group forms a hydrogen bond with Glu 260 of synthesized derivatives 5b, 5c, 5d, 5e, and 5h. The vast majority of freshly developed compounds obeyed Lipinski's rule of five, which is in line with the results that the ADMET model predicted. Additionally, molecular docking evaluation and molecular dynamics simulation investigations against the proteins AURKA and VEGFR-2 were conducted for the synthesized compounds to incorporate both in silico and in vitro data. The findings revealed that almost all of the compounds had considerable binding to AURKA and VEGFR-2 residues, with binding affinities ranging from -9.8 to -7.9 kcal/mol. Consequently, the results of the biological investigations and the docking scores demonstrated that thiazolidinone molecule 5e containing 4-chlorophenyl substituent may be considered as a potential moiety for glioblastoma cancer treatments.

Synthesis, Biological Evaluation, DNA Binding, and Molecular Docking of Hybrid 4,6-Dihydrazone Pyrimidine Derivatives as Antitumor Agents

In the present paper, on the basis of molecular hybridization, a series of 4,6-dihydrazone pyrimidine derivatives containing the pyridine moiety were synthesized, structurally characterized, and evaluated in vitro for their antitumor activity. According to the results, all the tested compounds demonstrated broad-spectrum antitumor activity against selected tumor cell lines (MCF-7, BGC-823, A549, and BEL-7402) and no obvious toxicity toward normal cells HL-7702. In particular, compounds 10a and 10f were found to be the most promising antitumor agents among the tested compounds against BGC-823 cells (IC₅₀ = 9.00 μM and 7.89 μM) and BEL-7402 cells (IC₅₀ = 6.70 μM and 7.66 μM), respectively. Compounds 10a and 10f exhibited higher potency against BGC-823 and BEL-7402 than the positive control 5-FU (IC₅₀ = 15.18 μM and 15.81 μM). Further mechanism investigations demonstrated that compounds 10a and 10f could significantly increase the level of cellular ROS and induce early apoptosis of BGC-823 cells in a dose-dependent manner. Moreover, the DNA binding results from UV/Vis, CD spectroscopy, and molecular docking studies indicated that 10a and 10f bind with DNA via groove binding and partial intercalation. These results demonstrated that 10a and 10f may serve as novel lead compounds for the discovery of more dihydrazone pyrimidine derivatives with improved antitumor potency and selectivity.

The hyaluronan-related genes HAS2, HYAL1-4, PH20 and HYALP1 are associated with prognosis, cell viability and spheroid formation capacity in ovarian cancer

Purpose

Hyaluronan modulates tumour progression, including cell adhesion, cohesion, proliferation and invasion, and the cancer stem cell phenotype. In ovarian cancer, high levels of stromal hyaluronan are associated with poor prognosis. In this work, hyaluronan synthases (HAS1-3) and hyaluronidases (HYAL1-4, PH-20, HYALP1) were examined with regard to different levels of gene expression and its influence on ovarian cancer patients’ survival. The impact of a siRNA depletion of HAS2 was investigated in vitro.

Methods

Using the Kaplan–Meier Plotter tool, we investigated the influence of hyaluronic synthases and hyaluronidases on the survival of a collective of 1435 ovarian cancer patients. Differences in gene expression between normal (n = 46) and cancerous (n = 744) ovarian tissue were examined using the TNMplot database. Following an evaluation of hyaluronan-related gene expression in the ATCC ovarian cancer panel, we studied SKOV3 and SW 626 ovarian cancer cells subjected to HAS2 siRNA or control siRNA treatment in terms of HAS1-3, HYAL2 and HYAL3 mRNA expression. We investigated the ability to form spheroids using the Hanging Drop method and the response to chemotherapy at different concentrations using the MTT Assay. By STRING analysis, interactions within the enzymes of the hyaluronic acid system and with binding partners were visualized.

Results

HAS1, HYAL1 and HYAL4 mRNA expression is significantly upregulated, whereas HAS2, HYAL2 and HYAL3 mRNA expression is significantly downregulated in ovarian cancer tissue compared to controls. HAS2 improves cell viability, the capability to form tumour spheroids and has a negative prognostic value regarding overall survival. Lower HAS2 expression and high expression of HYAL2 and HYAL3 favours the survival of ovarian cancer patients. HAS2 knockdown cells and control cells showed a moderate response to combinatorial in vitro chemotherapy with taxol and cisplatin.

Conclusion

In conclusion, our study shows that the hyaluronic acid system has a relevant influence on the survival of ovarian cancer patients and could therefore be considered as a possible prognostic factor.

Selective in vitro cytotoxicity effect of Drimia calcarata bulb extracts against p53 mutant HT-29 and p53 wild-type Caco-2 colorectal cancer cells through STAT5B regulation

Colorectal cancer is the fourth leading cause of oncological-related deaths and the third most diagnosed malignancy, worldwide. The emergence of chemoresistance is a fundamental drawback of colorectal cancer therapies and there is an urgent need for novel plant-derived therapeutics. In this regard, other compounds are needed to improve the efficacy of treatment against colorectal cancer. Medicinal plants have been effectively used by traditional doctors for decades to treat various ailments with little to no side effects. Drimia calcarata (D. calcarata) is one of the plants used by Pedi people in South Africa to treat a plethora of ailments. However, the anticancer therapeutic use of D. calcarata is less understood. Thus, this study was aimed at evaluating the potential anticancer activities of D. calcarata extracts against human colorectal cancer cells. The phytochemical analysis and antioxidant activity were analysed using LC-MS, DPPH, and FRAP. The inhibitory effects and IC50 values of D. calcarata extracts were determined using the MTT assay. Induction of cellular apoptosis was assessed using fluorescence microscopy, the Muse® Cell Analyser, and gene expression analysis by Polymerase Chain Reaction (PCR). Water extract (WE) demonstrated high phenolic, tannin, and flavonoid contents than the methanol extract (ME). LC-MS data demonstrated strong differences between the ME and WE. Moreover, WE showed the best antioxidant activity than ME. The MTT data showed that both ME and WE had no significant activity against human embryonic kidney Hek 293 cell line that served as non-cancer control cells. Caco-2 cells demonstrated high sensitivity to the ME and demonstrated resistance toward the WE, while HT-29 cells exhibited sensitivity to both D. calcarata extracts. The expression of apoptosis regulatory genes assessed by PCR revealed an upregulation of p53 by ME, accompanied by downregulation of Bcl-2 and high expression of Bax after treatment with curcumin. The Bax gene was undetected in HT-29 cells. The methanol extract induced mitochondrial-mediated apoptosis in colorectal Caco-2 and HT-29 cells and WE induced the extrinsic apoptotic pathway in HT-29 cells. ME downregulated STAT1, 3, and 5B in HT-29 cells. The D. calcarata bulb extracts, therefore, contain potential anticancer agents that can be further targeted for cancer therapeutics.

Medical Device Industry Approaches for Addressing Sources of Failing Cytotoxicity Scores

To ensure patient safety, medical device manufacturers are required by the Food and Drug Administration and other regulatory bodies to perform biocompatibility evaluations on their devices per standards, such as the AAMI-approved ISO 10993-1:2018 (ANSI/AAMI/ISO 10993-1:2018).However, some of these biological tests (e.g., systemic toxicity studies) have long lead times and are costly, which may hinder the release of new medical devices. In recent years, an alternative method using a risk-based approach for evaluating the toxicity (or biocompatibility) profile of chemicals and materials used in medical devices has become more mainstream. This approach is used as a complement to or substitute for traditional testing methods (e.g., systemic toxicity endpoints). Regardless of the approach, the one test still used routinely in initial screening is the cytotoxicity test, which is based on an in vitro cell culture system to evaluate potential biocompatibility effects of the final finished form of a medical device. However, it is known that this sensitive test is not always compatible with specific materials and can lead to failing cytotoxicity scores and an incorrect assumption of potential biological or toxicological adverse effects. This article discusses the common culprits of in vitro cytotoxicity failures, as well as describes the regulatory-approved methodology for cytotoxicity testing and the approach of using toxicological risk assessment to address clinical relevance of cytotoxicity failures for medical devices. Further, discrepancies among test results from in vitro tests, use of published half-maximal inhibitory concentration data, and the derivation of their relationship to tolerable exposure limits, reference doses, or no observed adverse effect levels are highlighted to demonstrate that although cytotoxicity tests in general are regarded as a useful sensitive screening assays, specific medical device materials are not compatible with these cellular/in vitro systems. For these cases, the results should be analyzed using more clinically relevant approaches (e.g., through chemical analysis or written risk assessment).

Medical Device Industry Approaches for Addressing Sources of Failing Cytotoxicity Scores

To ensure patient safety, medical device manufacturers are required by the Food and Drug Administration and other regulatory bodies to perform biocompatibility evaluations on their devices per standards, such as the AAMI-approved ISO 10993-1:2018 (ANSI/AAMI/ISO 10993-1:2018).However, some of these biological tests (e.g., systemic toxicity studies) have long lead times and are costly, which may hinder the release of new medical devices. In recent years, an alternative method using a risk-based approach for evaluating the toxicity (or biocompatibility) profile of chemicals and materials used in medical devices has become more mainstream. This approach is used as a complement to or substitute for traditional testing methods (e.g., systemic toxicity endpoints). Regardless of the approach, the one test still used routinely in initial screening is the cytotoxicity test, which is based on an in vitro cell culture system to evaluate potential biocompatibility effects of the final finished form of a medical device. However, it is known that this sensitive test is not always compatible with specific materials and can lead to failing cytotoxicity scores and an incorrect assumption of potential biological or toxicological adverse effects. This article discusses the common culprits of in vitro cytotoxicity failures, as well as describes the regulatory-approved methodology for cytotoxicity testing and the approach of using toxicological risk assessment to address clinical relevance of cytotoxicity failures for medical devices. Further, discrepancies among test results from in vitro tests, use of published half-maximal inhibitory concentration data, and the derivation of their relationship to tolerable exposure limits, reference doses, or no observed adverse effect levels are highlighted to demonstrate that although cytotoxicity tests in general are regarded as a useful sensitive screening assays, specific medical device materials are not compatible with these cellular/in vitro systems. For these cases, the results should be analyzed using more clinically relevant approaches (e.g., through chemical analysis or written risk assessment).

d-Carvone inhibits the JAK/STAT3 signaling pathway and induced the apoptotic cell death in the human gastric cancer AGS cells

Globally, gastric cancer is one of the leading cause of death. Surgical and chemotherapy constitute an important treatment regimen. Unfortunately, less than 20 persons out of 100 patients are live on almost 5 years. Hence, a nontoxic, effective and significantly enhancing novel therapeutic agent is required. d-Carvone is a natural terpenoid present in the essential oils and abundant in the seeds of caraway, as well as known folk medication for diarrhea, acidity, and other gastric disorders. Nevertheless, the role of d-carvone on gastric cancer and its underlying molecular mechanism resides enigmatic. Cells were treated with d-carvone to find out the IC₅₀ by MTT assay. This study shows that 20 and 25 μM d-carvone has induced the reactive oxygen species production and mitochondrial membrane potential in gastric cancer AGS cells, which were evaluated by 2,7-dichlorofluoresceindiacetate and Rh123 staining methods, respectively. The effect of d-carvone against the Janus kinase 2 (JAK2)/signal transducer and activator of transcription 3 (STAT3) pathway was studied through immunoblotting. Then, we found that it effectively inhibited the proliferation of cell, and the induction of cell apoptosis was scrutinized by dual, 4',6-diamidino-2-phenylindole, and also propidium iodide staining methods. We also explored the fundamental molecular signaling mechanism of the d-carvone and our data depicts that d-carvone induced apoptosis cell death by mitochondrial reactive oxygen species production and downregulation of the and JAK and STAT3 signaling molecules. These overall findings support that the d-carvone inhibits the JAK/STAT3 signaling pathway and induces cell death in the gastric cancer AGS cells.

Differential mRNA expression of the main apoptotic proteins in normal and malignant cells and its relation to in vitro resistance

Background

Apoptosis plays an important role in the development and homeostasis of multicellular organisms and its deregulation may result in many serious diseases, including cancer. Now it is clear that some oncogenic mutations disrupt apoptosis, leading to tumour initiation, progression or metastasis. Here, expression of apoptotic genes in context of drug resistance was investigated.

Methods

We examined total of 102 samples from leukemic patients (n = 60) and patients with solid tumours (n = 42). We used RT-PCR to determine the levels of mRNA expression and the in vitro chemoresistance of leukemic cells was evaluated using the MTT assay.

Results

We found statistically significant increase in mRNA expression of all investigated proteins (p53, BAX, Bcl-2 and Bcl-XL) between the leukemia samples and leukocytes from healthy volunteers. We did not find any significant difference in mRNA levels among the solid tumour samples. Notably, we showed a significant positive correlation in both leukemic and solid tumour patient groups between p53 and BAX mRNA. We found that the highest values for the Bcl-2/BAX ratio were in solid tumours in comparison to leukemic cells or normal leukocytes. Moreover, we assessed the impact of p53 and BAX mRNA levels on the sensitivity of the leukemic cells to selected cytostatics.

Conclusions

Elevated levels of p53 and BAX mRNA may indicate cellular response to possible changes in genomic DNA integrity associated with malignant transformation. We suggest that the BAX gene is regulated by the p53 protein but the initiation of apoptosis through the transcription activation of BAX is blocked by the high levels of Bcl-2. Given that the apoptosis resistance mechanisms are different among oncological patients as well as stages of identical malignancy cases, personalized and specific combination therapy is proposed to be more effective in clinical application.

Microwave-assisted synthesis of chitosan biguanidine hydrochloride and its regulation on InsR and GLUT2 in insulin resistant HepG2 cells

CSGH increased glucose consumption of HepG2 cells by accelerating the expression of InsR and inhibiting the high-insulin-induced over-expression of GLUT2.

Buckwheat bioactive compounds, their derived phenolic metabolites and their health benefits

SCOPE

Buckwheat (BW) consumption has been associated with a broad range of health benefits: antioxidant, anti-inflammatory and anticancer. These beneficial effects have been partially related to the presence of flavonoids. However, some of these compounds (i.e., rutin and quercetin) are metabolized in the gastrointestinal tract generating derived phenolic metabolites. In this study, we investigated the biological activity of rutin (Ru), quercetin (Q) an their derived phenolic metabolites 3,4-dihydroxyphenylacetic acid (3,4-DHPAA), 3-hydroxyphenylacetic acid (3-HPAA), and 4-hydroxy-3-methoxyphenylacetic acid (homovanillic acid, HVA).

METHODS AND RESULTS

Q showed the highest antioxidant and reducing activity, and Ru the maximum chelating activity (85.33%). Antioxidant activity of 3,4-DHPAA was 5-fold higher than that of HVA, whereas their reducing activity was similar. The formation of methylglyoxal (MGO)-BSA and glucose-BSA (advanced glycation end products) was inhibited by Ru (98.5 and 92.7%), Q (95.6 and 89.1%) and 3,4-DHPPA (84.4.6 and 77.5%). Furthermore, Q (10-50 μM) and Ru (1-50 μM) downregulated the release of PGE₂ , IL-8 and MCP-1, molecules involved in the inflammatory response, in IL1β-inflamed myofibroblasts of colon CCD-18Co.

CONCLUSION

This study suggests that BW phytochemicals and their phenolic metabolites may be responsible for the beneficial effects against chronic diseases attributed to BW consumption.

Phenyl-guanidine derivatives as potential therapeutic agents for glioblastoma multiforme: catalytic syntheses, cytotoxic effects and DNA affinity

Glioblastoma is a highly malignant form of brain tumor. In the work described here, several substituted phenyl-guanidine derivatives were developed for application in glioblastoma treatment.

Protective Effect of Vanillic Acid against Hyperinsulinemia, Hyperglycemia and Hyperlipidemia via Alleviating Hepatic Insulin Resistance and Inflammation in High-Fat Diet (HFD)-Fed Rats

Excess free fatty acid accumulation from abnormal lipid metabolism results in the insulin resistance in peripheral cells, subsequently causing hyperinsulinemia, hyperglycemia and/or hyperlipidemia in diabetes mellitus (DM) patients. Herein, we investigated the effect of phenolic acids on glucose uptake in an insulin-resistant cell-culture model and on hepatic insulin resistance and inflammation in rats fed a high-fat diet (HFD). The results show that vanillic acid (VA) demonstrated the highest glucose uptake ability among all tested phenolic acids in insulin-resistant FL83B mouse hepatocytes. Furthermore, rats fed HFD for 16 weeks were orally administered with VA daily (30 mg/kg body weight) at weeks 13-16. The results show that levels of serum insulin, glucose, triglyceride, and free fatty acid were significantly decreased in VA-treated HFD rats (p < 0.05), indicating the protective effects of VA against hyperinsulinemia, hyperglycemia and hyperlipidemia in HFD rats. Moreover, VA significantly reduced values of area under the curve for glucose (AUCglucose) in oral glucose tolerance test and homeostasis model assessment-insulin resistance (HOMA-IR) index, suggesting the improving effect on glucose tolerance and insulin resistance in HFD rats. The Western blot analysis revealed that VA significantly up-regulated expression of hepatic insulin-signaling and lipid metabolism-related protein, including insulin receptor, phosphatidylinositol-3 kinase, glucose transporter 2, and phosphorylated acetyl CoA carboxylase in HFD rats. VA also significantly down-regulated hepatic inflammation-related proteins, including cyclooxygenase-2 and monocyte chemoattractant protein-1 expressions in HFD rats. These results indicate that VA might ameliorate insulin resistance via improving hepatic insulin signaling and alleviating inflammation pathways in HFD rats. These findings also suggest the potential of VA in preventing the progression of DM.

PEGylated liposomes of anastrozole for long-term treatment of breast cancer: in vitro and in vivo evaluation

The aim of present study was to develop conventional and PEGylated (long circulating), liposomes containing anastrozole (ANS) for effective treatment of breast cancer. ANS is a third-generation non-steroidal aromatase inhibitor of the triazole class used for the treatment of advanced and late-stage breast cancer in post-menopausal women. Under such disease conditions the median duration of therapy should be prolonged until tumor regression ends (>31 months). Liposomes were prepared by the thin film hydration method by using ANS and various lipids such as soyaphosphatidyl choline, cholesterol and methoxy polyethylene glycol distearoyl ethanolamine in different concentration ratios and evaluated for physical characteristics, in vitro drug release and stability. Optimized formulations of liposome were studied for in vitro cytotoxic activity against the BT-549 and MCF-7 cell lines and in vivo behavior in Wistar rats. Preformulation studies, both Fourier transform infrared study and differential scanning calorimetry analysis showed no interaction between the drug and the excipients used in the formulations. The optimized formulations AL-07 and AL-09 liposomes showed encapsulation efficiencies in the range 65.12 ± 1.05% to 69.85 ± 3.2% with desired mean particle size distribution of 101.1 ± 5.9 and 120.2 ± 2.8 nm and zeta potentials of -43.7 ± 4.7 and -62.9 ± 3.5 mV. All the optimized formulations followed Higuchi-matrix release kinetics and when plotted in accordance with the Korsemeyer-Peppas method, the n-value 0.5 < n < 1.0 suggests an anomalous (non-Fickian) transport. Likewise, the PEGylated liposomes showed greater tumor growth inhibition on BT-549 and MCF-7 cell lines from in vitro cytotoxicity studies (p < 0.05). Pharmacokinetic study of conventional and PEGylated liposomes in Wistar rats demonstrated a 3.33- and 20.28-fold increase in AUC(0-∞) values when compared to pure drug (p < 0.001). Among the formulations, PEGylated liposomes showed encouraging results by way of their long circulation and sustained delivery properties for effective treatment of breast cancer.

Dual AO/EB staining to detect apoptosis in osteosarcoma cells compared with flow cytometry

BACKGROUND

The aim of this study was to evaluate the ability of dual acridine orange/ethidium bromide (AO/EB) staining to detect tumor cell apoptosis. According to apoptosis-associated changes of cell membranes during the process of apoptosis, a clear distinction is made between normal cells, early and late apoptotic cells, and necrotic cells.

MATERIAL AND METHODS

We cultured human osteosarcoma cells with 30, 60, and 120 µg/ml kappa-selenocarrageenan. To assess the rates of cell proliferation and apoptosis, cells were fluorescently stained with acridine orange/ethidium bromide (AO/EB) or stained with propidium iodide (PI) and analyzed by flow cytometry. All experiments were repeated at least 3 times.

RESULTS

Normal tumor cells, early and late apoptotic cells, and necrotic cells were examined using fluorescent microscopy. Early-stage apoptotic cells were marked by crescent-shaped or granular yellow-green acridine orange nuclear staining. Late-stage apoptotic cells were marked with concentrated and asymmetrically localized orange nuclear ethidium bromide staining. Necrotic cells increased in volume and showed uneven orange-red fluorescence at their periphery. Cells appeared to be in the process of disintegrating. The percentage of apoptotic osteosarcoma cells detected by dual acridine orange/ethidium bromide (AO/EB) staining was not significantly different from that detected using flow cytometry (P>0.05).

CONCLUSIONS

Our results suggest that dual acridine orange/ethidium bromide staining is an economic and convenient method to detect apoptosis in tumor cells and to test tumor chemosensitivity compared with flow cytometry.

Ratio of lysine to methionine alters expression of genes involved in milk protein transcription and translation and mTOR phosphorylation in bovine mammary cells

This study was conducted to determine the optimum ratio of lysine and methionine (Lys:Met) to enhance milk protein concentration in vitro, focusing on the regulation of genes related to the JAK2-STAT5 and the mammalian target of rapamycin (mTOR) signaling pathways. A preliminary dose response study revealed that casein concentration peaked (2.5-2.7 ppm) at a supplemental Lys concentration of 1.2 mM and Met at 0.5 mM. At the peak casein concentration cell proliferation rate also was higher. Furthermore, the expression of CSN1S1, CSN1S2, CSN2, CSN3, LALBA, JAK2, STAT5, and MTOR was upregulated with both Lys and Met compared with the control. A subsequent experiment was conducted as a 5 × 3 factorial design with supplemental Lys plus Met at different ratios. When the supplemental concentration of Lys was 1.2 mM and Met was 0.4 mM (∼3:1), the concentration of casein peaked. Therefore, we measured gene expression, mTOR protein expression, and phosphorylated mTOR (p-mTOR) in cultures incubated with 3:1 Lys:Met (Lys&Met). Expression of CSN1S1 and LALBA were the most highly expressed genes (P < 0.01). The upregulation of CSN2, CSN3, CSN1S2 isoforms (P < 0.01) and JAK2, ELF5, mTOR (P < 0.05) was also observed. Total mTOR protein expression was greater (P < 0.05) with Lys alone and also Lys&Met. However, Lys&Met resulted in the greatest (P < 0.05) p-mTOR. Results suggest that peak concentration of casein at a supplemental 3:1 Lys:Met is driven in part via upregulation of the mRNA expression of components of the JAK-STAT and mTOR pathways.

Hypoxia influences stem cell-like properties in multidrug resistant K562 leukemic cells

OBJECTIVES

The present study investigates the potential role of hypoxia in maintaining stem cell-like properties and therapeutic resistance in K562 leukemic cell.

METHODS

Western blot, flow cytometry and cell viability assays were used to investigate the effects of hypoxia (1% O2) on cell proliferation, drug resistance and expression of the hypoxia inducible factor-2α (HIF-2α), the octamer-binding transcription factor 4 (Oct4), CD133, CD34 and the ATP-binding cassette sub-family G member 2 (ABCG2) as well as Smad2 phosphorylation in the drug resistant cell line K562/DOX and its parental cell line.

RESULTS

Hypoxia induced growth inhibition and significantly upregulated HIF-2α, CD133, Oct4, CD34 and ABCG2 expression in the wild type K562 cells (p<0.05). The IC50 of doxorubicin was also enhanced about 2.5-fold in hypoxia. In contrast, the K562/DOX cells, which showed significantly higher ABCG2 expression and IC50 for various drugs, no significant difference in cell proliferation was observed between hypoxia and normoxia. The hypoxia-induced upregulation of HIF-2α, CD133, Oct4, CD34 and ABCG2 expression was significantly lower than in the wild type cells (p<0.05). Moreover, hypoxia induced the phosphorylation of Smad2 and additional treatment with SD-208, an inhibitor of the TGF-β receptor I kinase, resulted in a dose-dependent downregulation of CD133 and Oct4 in the K562/DOX cells.

CONCLUSIONS

Hypoxia plays an important role in enhancing the stem cell-like properties and to induce multidrug resistance of leukemia cells. The activation of the TGF-β/Smad2 signaling pathway may be involved in the regulation of this pathophysiological process.

Tyrosinase modulation by five Rwandese herbal medicines traditionally used for skin treatment

ETHNOPHARMACOLOGICAL RELEVANCE

Traditional herbal medicines provide an interesting, largely unexplored source for the development of potential new drugs and skin-care cosmetics. Some herbal extracts are known to be inhibitors of melanin formation, sometimes more potent than the classical inhibitors, hydroquinone/arbutin or kojic acid, and are not associated with melanocytes cytotoxicity or mutagenicity. Such plants are used in traditional medicine in many countries, particularly in Africa, for skin lightening.

AIM OF THE STUDY

To evaluate in vitro the ability of Rwandese medicinal plants, traditionally used for the treatment of skin (discoloration and attenuation of discolored spots), to modulate pigmentation and tyrosinase activity.

MATERIALS AND METHODS

Based on an ethnopharmacological survey, five herbs [Brillantaisia cicatricosa Lindau (Acanthaceae), Chenopodium ugandae (Aellen) Aellen (Chenopodiaceae), Dolichopentas longiflora Oliv. (Rubiaceae), Protea madiensis Oliv. (Proteaceae) and Sesamum angolense Welw. (Pedaliaceae)] were selected. Twenty-seven extracts, obtained by treating the herbs with increasing polarities solvents, were investigated for their effects on cell viability (MTT test) and on pigmentation: inhibition of the enzyme tyrosinase (colorimetry of reaction products, measurement of enzyme activity, TLC-autography; studies on crude cellular extracts obtained from normal melanocytes and on a mushroom tyrosinase) and measurement of melanogenesis by human melanoma cells.

RESULTS

None of the tested plant extracts were cytotoxic on tested human melanoma cell lines, except for Dolichopentas longiflora (IC50 of leaves n-hexane extract, 4μg/ml for MM028 and 4.5μg/ml for MM001; IC50 of roots ethyl acetate extract, 0.8μg/ml for MM028 and 3.9μg/ml for MM001). Almost all extracts inhibited melanogenesis in a melanoma whole cells overall pigmentation assay, a model reflecting the entire cycle of melanogenesis. All the Protea madiensis extracts quite strongly inhibited melanogenesis and, surprisingly, one of the Dolichopentas longiflora leaves extracts was found to increase melanogenesis. These results were confirmed by the modulation of pigmentation reactions by crude cellular extracts obtained from normal melanocytes; interestingly, one of the extracts (Dolichopentas longiflora ethyl acetate extract) is even more active (61% at 500μg/ml) than kojic acid (<3% at 142μg/ml and 68% at 1421μg/ml). In a mushroom tyrosinase inhibition assay, data obtained on some extracts fairly agree with pigmentation inhibition measured on melanocytes proteins as, for example, the methanol extract of Protea madiensis. While a few others extract display discording data, this probably reflects either differences between human and mushroom tyrosinase, interference with melanocytes enzymes at later steps than tyrosinase or the simultaneous presence of compounds with conflicting activities in a given extract.

CONCLUSIONS

Ethnopharmacological data represent an efficient approach to discover active herbs. Some of the selected medicinal plants clearly show potent tyrosinase inhibitions while one extract significantly increases cell pigmentation; one extract contains potent growth melanocytes inhibitors.

Anvirzel™ in combination with cisplatin in breast, colon, lung, prostate, melanoma and pancreatic cancer cell lines

Background

Platinum derivatives are used widely for the treatment of many cancers. However, the toxicity that is observed makes imperative the need for new drugs, or new combinations. Anvirzel™ is an extract which has been demonstrated with experimental data that displays anticancer activity. The aim of the present study is to determine whether the combination of Cisplatin and Anvirzel™ has a synergistic effect against different types of cancer.

Materials and methods

To measure the efficacy of treatment with Cisplatin and Anvirzel™, methyl-tetrazolium dye (MTT) chemosensitivity assays were used incorporating established human cancer cell lines. Measurements were performed in triplicates, three times, using different incubation times and different concentrations of the two formulations in combination or on their own. t-test was used for statistical analysis.

Results

In the majority of the cell lines tested, lower concentrations of Anvirzel™ induced a synergistic effect when combined with low concentrations of Cisplatin after an incubation period of 48 to 72 h. The combination of Anvirzel™/Cisplatin showed anti-proliferative effects against a wide range of tumours.

Conclusion

The results showed that the combination of Anvirzel™ and Cisplatin is more effective than monotherapy, even when administered at low concentrations; thus, undesirable toxic effects can be avoided.

Metastatic soft tissue sarcoma chemotherapy: an opportunity for personalized medicine

BACKGROUND

Soft tissue sarcoma (STS) includes biologically and histologically diverse mesenchymal tumors that are relatively chemotherapy-resistant compared with other sarcoma subtypes.

METHODS

The authors discuss the clinical challenges frequently encountered by medical oncologists and review the literature for predictive strategies to systematically approach chemotherapy decision making.

RESULTS

There are no clinically validated predictive tests for chemotherapeutic response or resistance in STS. Clinical features including histology, stage, and patient age are currently used to guide therapy decisions in STS.

CONCLUSIONS

A method to predict response or resistance to chemotherapy, utilizing both targeted and conventional agents, would be beneficial in reducing toxicity and improving response rates for patients with STS and also in designing clinical trials for this disease.

Genome-wide identification of possible methylation markers chemosensitive to targeted regimens in colorectal cancers

PURPOSE

Few efficient methylation markers of chemosensitivity have been discovered. The genome-wide analysis of methylation markers is needed to identify chemosensitive candidates to targeted therapy.

METHODS

This study describes a two-step process to select chemosensitive candidates of methylation genes. A genome-wide screening of methylation genes was performed using a Beadarray and an in vitro chemosensitivity assay of 119 colorectal cancers (CRCs). Ten candidate genes identified during the initial screening were verified by biological utility assessment using cell viability assays of transfected CRC cells.

RESULTS

Five methylation genes related to sensitivity to bevacizumab regimens (RASSF1, MMP25, KCNQ1, ESR1, and GALR2) or cetuximab regimens (SCL18A2, GPX7, NID2, IGFBP3, and ALX4) were chosen during the first step. A viability assay revealed that GALR2-overexpressing HCT116 cells were significantly more chemosensitive to bevacizumab regimens than control cells (P = 0.022 and 0.019 for bevacizumab with FOLFIRI and FOLFOX, respectively), concurrently verified on a caspase-3 activity assay. GPX7- or ALX4-overexpressed RKO cells were significantly less viable to cetuximab regimens compared to control cells (GPX7: P = 0.027 each for cetuximab with FOLFIRI and FOLFOX; ALX4: P = 0.049 and 0.003 for cetuximab with FOLFIRI and FOLFOX, respectively), but caspase-3 activity was not prominent in GPX7-overexpressed RKO cells.

CONCLUSIONS

Two novel genes, GALR2 and ALX4, have been identified as chemosensitive methylation candidates to bevacizumab and cetuximab regimens, respectively. As our study did not include a clinical association study, the two candidates should be validated in large clinical cohorts, hopefully predicting responsive patients to targeted regimens.

Standardization of biochemical profile of mesenchymal cell materials by probing the level of dehydrogenase activity

It is demonstrated that the output optical signal of MTT test is directly proportional to the number of viable cells in the primary culture of mesenchymal cells (skin fibroblasts and mesenchymal stem cells from the bone marrow, placenta, and umbilical cord). The slope of the best curve in coordinates "cell number - optical signal" reflecting specific productivity of MTT-formazan characterizes mean dehydrogenase activity of cells and their physiological activity. It was found that in vitro dehydrogenase activity of primary cultures of mesenchymal cells increased during the first 3-5 passages and then tended to decrease. The variant of MTT method presented here can be used for standardization of cell materials.

Novel chemosensitive single-nucleotide polymorphism markers to targeted regimens in metastatic colorectal cancer

PURPOSE

Methods for predicting individual responsiveness to targeted chemotherapy are urgently needed, considering the frequent resistance and extremely high cost.

EXPERIMENTAL DESIGN

A chemosensitive single-nucleotide polymorphism (SNP) discovery schema is presented that utilizes (i) genome-wide SNP screening with a human SNP array and an in vitro chemosensitivity assay in 118 colorectal cancers, (ii) clinical association analysis in the other 98 patients who had received chemotherapy for metastatic cancer, and (iii) biological utility assessment using cell viability assays of transfected colorectal cancer (CRC) cells.

RESULTS

Nine SNPs related to bevacizumab and cetuximab regimen sensitivity were chosen during screening. Overall responses for bevacizumab regimens revealed that patients carrying the TT genotype at ANXA11 rs1049550 or at least one G allele at LINS1 rs11247226 seemed greater chemosensitive than those carrying at least one C allele or the AA genotype, respectively (P < 0.05). For cetuximab regimens, patients carrying the GG genotype at DFNB31 rs2274159 or LIFR rs3729740 seemed greater chemosensitive than those carrying at least one A allele (P = 0.025 and P = 0.07). Cytotoxicity analyses showed that all RKO and HCT116 CRC clones transfected with the G allele at LIFR rs3729740 and the C allele at ISX rs361863 were more sensitive to cetuximab regimens than those with the A and T allele, respectively (P ≤ 0.001-0.024).

CONCLUSIONS

Chemosensitive SNP markers were identified using a novel three-step process. The candidate marker LIFR rs3729740 and possibly ISX rs361863 will hopefully predict responsive patients to cetuximab regimens, although further validation is needed in large cohorts.

Resistance of stem-like cells from neuroblastoma cell lines to commonly used chemotherapeutic agents

BACKGROUND

Cancer stem cell theory suggests that the presence of tumor initiating stem-like cells in cancers may be responsible for cancer progression and relapse. CD133 cell surface maker expression has been used to identify stem-like cells in cancer cell lines. Our goal was to identify such cells in neuroblastoma cell lines and to study the cytotoxicity of common anticancer drugs for those cells.

MATERIALS AND METHODS

CD133+ cells from SK-N-SH and SK-N-BE cell lines were isolated using magnetic microbeads. Cytotoxicity of four anticancer drugs was studied on CD133+ and CD133- populations. The percentage of live, apoptotic, and dead cells in each population after drug treatment was estimated by MTT and PI/Annexin-binding assays. Western blot analyses were used to identify differences in the expression of kinases.

RESULTS

Eight to 10% of SK-N-SH and 3-5% of SK-N-BE cells were CD133+. These cells were more resistant than CD133- cells to all four chemotherapeutic agents tested in the MTT assay. Decreased apoptosis was observed in CD133+ cells compared to CD133- cells by PI/Annexin V-binding assay. Western blot analysis showed that CD133+ cells expressed less MKP-1. Phosphorylated forms of both ERK and P-38 kinases were expressed at higher levels in CD133+ cells than in CD133- cells.

CONCLUSIONS

This study suggests that CD133+ cells are more resistant to anticancer drugs than CD133- cells. Differences in the expression and phosphorylation of kinases could be partially responsible for this difference. Targeting CD133-expressing cells could be a strategy to develop more effective treatments for neuroblastoma.

Effect of guava (Psidium guajava L.) leaf extract on glucose uptake in rat hepatocytes

People in oriental countries, including Japan and Taiwan, boil guava leaves (Psidium guajava L.) in water and drink the extract as a folk medicine for diabetes. The present study investigated the enhancement of aqueous guava leaf extract on glucose uptake in rat clone 9 hepatocytes and searched for the active compound. The extract was eluted with MeOH-H(2)O solutions through Diaion, Sephadex, and MCI-gel columns to separate into fractions with different polarities. The uptake test of 2-[1-(14)C] deoxy-D-glucose in rat clone 9 hepatocytes was performed to evaluate the hypoglycemic effect of these fractions. The active compound was identified by nuclear magnetic resonance analysis and high-performance liquid chromatography (HPLC). The results revealed that phenolics are the principal component of the extract, that high polarity fractions of the guava leaf extract are enhancers to glucose uptake in rat clone 9 hepatocytes, and that quercetin is the major active compound. We suggest that quercetin in the aqueous extract of guava leaves promotes glucose uptake in liver cells, and contributes to the alleviation of hypoglycemia in diabetes as a consequence.

DNA damage induced by cis- and carboplatin as indicator for in vitro sensitivity of ovarian carcinoma cells

Background

The DNA damage by platinum cytostatics is thought to be the main cause of their cytotoxicity. Therefore the measurement of the DNA damage induced by cis- and carboplatin should reflect the sensitivity of cancer cells toward the platinum chemotherapeutics.

Methods

DNA damage induced by cis- and carboplatin in primary cells of ovarian carcinomas was determined by the alkaline comet assay. In parallel, the reduction of cell viability was measured by the fluorescein diacetate (FDA) hydrolysis assay.

Results

While in the comet assay the isolated cells showed a high degree of DNA damage after a 24 h treatment, cell viability revealed no cytotoxicity after that incubation time. The individual sensitivities to DNA damage of 12 tumour biopsies differed up to a factor of about 3. DNA damage after a one day treatment with cis- or carboplatin correlated well with the cytotoxic effects after a 7 day treatment (r = 0,942 for cisplatin r = 0.971 for carboplatin). In contrast to the platinum compounds the correlation of DNA damage and cytotoxicity induced by adriamycin was low (r = 0,692), or did not exist for gemcitabine.

Conclusion

The measurement of DNA damage induced by cis- and carboplatin is an accurate method to determine the in vitro chemosensitivity of ovarian cancer cells towards these cytostatics, because of its quickness, sensitivity, and low cell number needed.

The effect of high frequency steep pulsed electric fields on in vitro and in vivo antitumor efficiency of ovarian cancer cell line skov3 and potential use in electrochemotherapy

BACKGROUND

Patients received electrochemotherapy often associated with unpleasant sensations mainly result from low-frequency electric pulse induced muscle contractions. Increasing the repetition frequency of electric pulse can reduce unpleasant sensations. However, due to the specificity of SPEF, frequency related antitumor efficiency need to be further clarified. The aim of this study was to compare in vitro cytotoxic and in vivo antitumor effect on ovarian cancer cell line SKOV3 by SPEF with different repetition frequencies. Explore potential benefits of using high frequency SPEF in order to be exploitable in electrochemotherapy.

METHODS

For in vitro experiment, SKOV3 cell suspensions were exposed to SPEF with gradient increased frequencies (1, 60, 1000, 5000 Hz) and electric field intensity (50, 100, 150, 200, 250, 300, 350, 400 V/cm) respectively. For in vivo test, SKOV3 subcutaneous implanted tumor in BALB/c nude mice (nu/nu) were exposure to SPEF with gradient increased frequencies (1, 60, 1000, 5000 Hz) and fixed electric field intensity (250 V/cm) (7 mice for each frequency and 7 for control). Antitumor efficiency was performed by in vitro cytotoxic assay and in vivo tumor growth inhibition rate, supplemented by histological and TEM observations. Data were analyzed using one-way ANOVA followed by the comparisons of multiple groups.

RESULTS

SPEF with a given frequency and appropriate electric field intensity could achieve similar cytotoxicity until reached a plateau of maximum cytotoxicity (approx. 100%). SPEF with different frequencies had significant antitumor efficiency in comparison to the control group (P < 0.05). However, there was no difference in tumor responses among test groups (P > 0.05). Histological and TEM observations demonstrated obvious cell damages in response to SPEF exposure. Furthermore, SPEF with 5 kHz could induce apoptosis under TEM observations both in vitro and in vivo.

CONCLUSION

SPEF with high frequency could also achieve similar antitumor efficiency which can be used to reduce unpleasant sensations in tumor electrical treatment. Our research proposed potential applications of using high frequency SPEF in clinical cancer treatment.

In vitro assays for the evaluation of drug resistance in tumor cells

Oncologic diseases are among leading cause of mortality in developed countries. Despite significant progress, the use of standard cytotoxic chemotherapy has reached a therapeutical plateau. Currently, the process of selecting chemotherapy represents a trial and error method neglecting biological individuality of tumor and its bearer. The improvement of treatment results is expected from ex vivo drug sensitivity testing which may allow to choose the most effective drug for individual patient and to exclude agents to which the tumor cells exert resistance. New techniques and rapidly increasing knowledge about the molecular basis of malignant diseases provide important opportunities for the future of chemotherapy. This paper reviews current methods used to test the resistance of tumor cells to a panel of anticancer agents in vitro. In addition, we focused on the in vitro MTT assay which represents one of major technique for testing of tumor cell resistance to anticancer agents.

Comparison of antitumor effects of multitargeted tyrosine kinase inhibitors in acute myelogenous leukemia

We compared the antitumor activities of the multitargeted tyrosine kinase inhibitors imatinib, sorafenib, and sunitinib to determine which inhibitor is best suited to be used for the treatment of acute myelogenous leukemia (AML). In nine human AML cell lines, sorafenib and sunitinib were more potent inhibitors of cellular proliferation than imatinib (IC50, 0.27 to >40, 0.002-9.1, and 0.007-13 micromol/L for imatinib, sorafenib, and sunitinib, respectively). Sorafenib and sunitinib were potent inhibitors of cells with fms-like tyrosine kinase 3 internal tandem duplication (IC50, 2 and 7 nmol/L) and c-KIT N822K mutations (IC50, 23 and 40 nmol/L). In four cell lines (MV4-11, Kasumi-1, KG-1, and U937) that spanned a range of drug sensitivities, sorafenib and sunitinib had similar activity in apoptosis and cell cycle assays, except that sunitinib did not promote apoptosis in U937 cells. Both drugs inhibited mitogen-activated protein kinase signaling but had no effect on AKT signaling in most of the cell lines tested. Sorafenib was substantially more bound than sunitinib in human plasma (unbound fraction, 0.59% versus 8.4%) and cell culture medium (unbound fraction, 1.3% versus 39%), indicating that sorafenib was more potent than sunitinib and that unbound sorafenib concentrations with activity against most AML cell lines are achievable in vivo. There was more intracellular accumulation of sorafenib than of sunitinib and imatinib in AML cells. Between 1 and 10 micromol/L, sorafenib inhibited the proliferation of six of nine primary AML blast samples by > or =50%. Our results highlight the pharmacologic features of sorafenib that may provide it an advantage in the treatment of AML.

Cell viability of acute myeloid leukaemia blasts in culture correlates with treatment outcome

Despite the advances in understanding the pathophysiology of acute myeloid leukaemia (AML), the cure rate for acute myeloid leukaemia patients remains low. Cytogenetic abnormalities and age are the prognostic factors that guide treatment decisions. However, many AML patients still die. The biological factors that influence treatment outcome are largely unknown. Thus, the objective of our study was to use the in vitro viability test to correlate with treatment outcome. Acute myeloid leukaemia blasts demonstrated differing ability to survive in culture. Our examination of blast phenotype at various days in culture showed two possible growth directions. First, cells underwent maturation by increased expression of CD16 and down-regulated CD34 (a haemopoietic stem cell marker). These cells also appeared to have undergone apoptosis. Alternatively, cells continued to survive in culture and maintained high expression of CD34. An MTT assay was carried out to determine viability after three days of culture. Lower optical density values were obtained for samples that underwent apoptosis and higher values were obtained for samples that survived in culture. Apoptosis was measured by Annexin V/propidium iodide staining. A comparison between results of MTT assay and duration of disease free survival revealed that a higher viability in vitro correlated significantly with shorter survival duration in the patient (R -0.761, p=0.002, n=13). Thus, this study further supports the hypothesis that AML patients with poor survival may be related to having blasts with a biologically more immature or stem cell-like nature.

Preclinical antitumor efficacy evaluation of dendrimer-based methotrexate conjugates

Our previous studies have demonstrated the in-vitro and in-vivo targeting of a generation-5 (G5) dendrimer-based multifunctional conjugate, which used folic acid (FA) as the targeting agent and methotrexate (MTX) as the chemotherapeutic drug. For the synthesized G5-FA-MTX nanodevice conjugate to be clinically applicable as a cancer therapeutic drug, it is important that the compound elicits cytotoxicity specifically and consistently. The aim of this work was to evaluate four independently synthesized batches of G5-FA-MTX conjugates for their cytotoxic potential and specificity. For determination of specificity, we have used a unique 'coculture' assay in which FA receptor-positive and FA receptor-negative cells were cultured together and have examined the preferential killing of the former. The results of our study show the batch-to-batch consistency and specificity of the G5-FA-MTX nanodevice in the preferential killing of FA receptor-positive cells. The coculture assay shows the consistency of the four different G5-FA-MTX conjugate lots in the specific killing of targeted cells. Further in-vivo studies are, however, necessary to prove the clinical potential of this targeted therapeutic nanodevice.

Anti-inflammatory and anti-oxidant properties of telmisartan in cultured human umbilical vein endothelial cells

PURPOSE

To study whether telmisartan, an angiotensin II (AII) receptor blocker (ARB), modulates endothelial inflammation and oxidative cell damage induced by AII-independent stimuli in cultured human umbilical vein endothelial cell (HUVEC)s.

METHODS

Endothelial inflammation, as reflected by increased VCAM-1 and ICAM-1 expression (ELISA), was induced by TNF-alpha, an inflammatory cytokine, and cell damage (COMET and MTT assay) by hydrogen peroxide, a reactive oxygen species. Losartan, another ARB, its active metabolites (EXP-3174, EXP-3179), dexamethasone, a synthetic steroid, and pyrrolidine dithiocarbamate (PDTC), an anti-oxidant, were the controls. The contribution of PPAR-gamma agonism was assessed through synthetic PPAR-gamma agonists and antagonists and the antagonism for AII-type 1 receptor-mediated stimuli by evaluating the interference against cell death induced by AII (MTT assay), a pro-apoptotic peptide that induces oxidative stress. The in vitro scavenging properties for oxyradicals were quantified by the TOSC assay.

RESULTS

Telmisartan and PDTC reduced TNF-alpha-stimulated VCAM-1 in a concentration-dependent manner while losartan, EXP-3174, EXP-3179 and dexamethasone were ineffective. All compounds did not modify ICAM-1 expression. PPAR-gamma agonists or antagonists did not interfere with the effect of telmisartan. Both ARBs antagonized AII-induced cell death but only telmisartan reduced hydrogen peroxide-induced cell damage. Telmisartan scavenged selectively hydroxyl radicals without affecting peroxyl radicals and peroxynitrite.

CONCLUSIONS

Telmisartan modulates pleiotropically TNF-alpha induced VCAM-1 expression and oxidative damage in vascular endothelium, possibly by acting as a hydroxyl radical scavenger. Those anti-inflammatory and antioxidant properties may contribute to the therapeutic effect, although the applicability of these data to the clinical situations has to be verified.

Streptococcus agalactiae GAPDH is a virulence-associated immunomodulatory protein

Certain extracellular proteins produced by several pathogenic microorganisms interfere with the host immune system facilitating microbial colonization and were thus designated virulence-associated immunomodulatory proteins. In this study, a protein with B lymphocyte stimulatory activity was isolated from culture supernatants of Streptococcus agalactiae strain NEM316. This protein, with an apparent molecular mass of 45 kDa, was identified as GAPDH by N-terminal amino acid sequencing. The gapC gene was cloned and expressed in Escherichia coli for the production of a recombinant histidyl-tagged protein. The recombinant GAPDH (rGAPDH), purified in an enzymatically active form, induced in vitro an up-regulation of CD69 expression on B cells from normal and BCR transgenic mice. In addition, rGAPDH induced an increase in the numbers of total, but not of rGAPDH-specific, splenic Ig-secreting cells in C57BL/6 mice treated i.p. with this protein. These in vitro- and in vivo-elicited B cell responses suggest that the B cell stimulatory effect of rGAPDH is independent of BCR specificity. A S. agalactiae strain overexpressing GAPDH showed increased virulence as compared with the wild-type strain in C57BL/6 mice. This virulence was markedly reduced in IL-10-deficient and anti-rGAPDH antiserum-treated mice. These results suggest that IL-10 production, which was detected at higher concentrations in the serum of rGAPDH-treated mice, is important in determining the successfulness of the host colonization by S. agalactiae and they highlight the direct role of GAPDH in this process. Taken together, our data demonstrate that S. agalactiae GAPDH is a virulence-associated immunomodulatory protein.

Methanol extract of the seaweed Gloiopeltis furcata induces G2/M arrest and inhibits cyclooxygenase-2 activity in human hepatocarcinoma HepG2 cells

It was previously reported that a methanol extract of Gloiopeltis furcata (MEGF), a kind of edible seaweed, inhibited the growth of several human cancer cell lines. In the present study, the effect of MEGF on the growth of human hepatocarcinoma HepG2 cells and its effect on the cyclooxygenases (COXs) expression were investigated. MEGF markedly reduced the viability of HepG2 cells and induced the G2/M arrest of the cell cycle in a concentration dependent manner. These effects were associated with the down-regulation of cyclin A, up-regulation of cyclin-dependent kinase (Cdk) inhibitor p21 (WAF1/CIP1) and dephosphorylation of Cdc25C. Furthermore, it was found that MEGF decreased the levels of COX-2 mRNA and protein expression without significant changes in the levels of COX-1, which was correlated with a decrease in prostaglandin E(2) (PGE(2)) synthesis. These findings indicate that MEGF may have a possible therapeutic potential in hepatoma cancer patients.

Potential involvement of serine/threonine protein phosphatases in apoptosis of HepG2 cells during selenite treatment

Selenium, an essential biological trace element present in both prokaryotic and eukaryotic cells, exerts its regulatory effect in a variety of cellular events, including cell growth, survival, and death. Selenium compounds have been shown in different cell lines to inhibit apoptosis by several mechanisms. Serine/threonine phosphatases (STPs) are potentially important in selenite-induced apoptosis because of their role in regulation of diverse set of cellular processes. In this study, the regulatory role of STPs in selenite-induced apoptosis has been implied by the use of two specific inhibitors: ocadaic acid and calyculin A. Our results show a decrease in cell density in HepG2 cells under selenite treatment. Resulting specific enzyme activities showed a concentration-dependent increase in all three phosphatase activities after 24 h in cells treated with 5 microM selenite and these activities decreased at 48 and 72 h. However, in cells treated with 10 microM selenite, PP2A and PP2B decreased at 48 h, whereas PP2C activity did not change at this dose. In cells treated with 25 microM, there was not a significant change in PP2C activity. These data suggest that the most specific response to selenite treatment was in PP2A and PP2B activities in a dose-dependent manner. Our results with OA and Cal-A further support the view that PP1 and PP2A might act as negative regulators of growth. With these data, we have first demonstrated the role of serine/threonine protein phosphatases in the signaling pathway of selenite-induced apoptosis and resulting cytotoxicity.

Uso de teste de químio-sensibilidade para escolha da quimioterapia adjuvante no câncer gástrico avançado

OBJETIVO: Introduzir e familiarizar em nosso meio o uso do teste de químio-sensibilidade MTT avaliando a ação de agentes quimioterápicos sobre células tumorais de 30 doentes com câncer gástrico avançado. Correlacionar os resultados do teste MTT com os aspectos clínicos, anátomo-patológicos e estádio utlizando a mesma metodologia do estudo realizado em pacientes japoneses na Universidade de Keio, Japão. MÉTODO: Foi realizado o teste MTT em tumores de 30 pacientes com diagnóstico de adenocarcinoma gástrico, submetidos ao tratamento cirúrgico no Departamento de Cirurgia da Faculdade de Ciências Médicas da Santa Casa de São Paulo. Foram estudados in vitro os seguintes agentes quimioterápicos: mitomicina C, doxorrubicina, cisplatina e 5-fluorouracil. RESULTADOS: Os índices de atividade sobre células tumorais foram: 16,6% para a mitomicina C, 10,0% para a doxorrubicina, 6,6% para a cisplatina e 6,6% para o 5-fluorouracil. Os resultados do teste MTT não tiveram correlação com a idade, sexo, aspectos microscópicos e estádio (p0,05). CONCLUSÕES: A ação dos agentes quimioterápicos estudados sobre células tumorais do câncer gástrico foi baixa. Os resultados da ação dos quimioterápicos in vitro não apresentou correlação estatística com a idade, sexo, aspectos microscópicos e estádio destes doentes. Utilizando a mesma metodologia, tanto em nosso meio como em pacientes japoneses, a quimio-sensibilidade se mostrou baixa em ambos os estudos, podendo-se deduzir também que os resultados da químiosensibilidade independe da etnia. Com o surgimento de novos agentes quimioterápicos, a expectativa é grande para melhores resultados na prática clínica. Com a utilização e difusão do teste MTT em nosso meio, poder-se-á criar protocolos e estudos multicêntricos para selecionar os quimioterápicos a serem utlizados.

Platelet-derived growth factor receptor independent proliferation of human glioblastoma cells: selective tyrosine kinase inhibitors lack antiproliferative activity

PURPOSE

The aim of this study was to investigate the role of platelet-derived growth factor (PDGF) and PDGF receptors (PDGFRs) in the proliferation of human glioblastoma cells as a prerequisite for a new therapeutic approach to the treatment of malignant brain tumors with selective tyrosine kinase inhibitors such as imatinib.

METHODS AND RESULTS

In the human glioblastoma cell lines U-87 MG, U-118 MG and U-373 MG different PDGF and PDGFR mRNAs were detected by RT-PCR, and the expression of the receptor proteins was demonstrated by immunostaining and flow cytometry. Moreover, functional activity of PDGFRs was demonstrated in PDGFRbeta expressing glioblastoma cell variants by measuring the mobilization of intracellular Ca(2+) upon PDGF-BB stimulation. However, addition of PDGF-BB to the serum-free culture medium had no stimulatory effect on cell proliferation. Furthermore, cell growth in serum-supplemented and serum-free medium was not affected by imatinib, leflunomide and AG-1296 at therapeutically relevant concentrations.

CONCLUSION

Our results suggest that clinical antitumor effects of imatinib on glioblastoma, if any, are not mediated by the PDGFR.

A selective inhibitor of the p110delta isoform of PI 3-kinase inhibits AML cell proliferation and survival and increases the cytotoxic effects of VP16

Current therapy for acute myeloid leukaemia (AML) is suboptimal with a high incidence of relapse. There is strong evidence that constitutive phosphoinositide 3-kinase (PI3K) activity plays a significant role in the pathophysiology of AML. PI3K products are derived from the activity of a number of PI3K catalytic isoforms (class I, II and III) but the relative contribution of these enzymes in AML remains unknown. As non-isoform-selective inhibitors of PI3K such as LY294002 may produce unwanted toxicity to normal tissues, we have investigated the role of the leukocyte-restricted p110delta PI3K isoform in 14 cases of AML. p110delta was detected in all cases whereas the expression levels of the other class I PI3Ks varied more widely, and were often undetectable. The p110delta-selective compound IC87114 inhibited constitutive phosphorylation of the PI3K target Akt/PKB and reduced cell number to a mean of 66+/-5% (range 14-88%). In eight cases, the combination of IC87114 and VP16 (a topoisomerase II inhibitor) was synergistic in reducing viable cell number, and was associated with a reduction in constitutive NF-kappaB activity. IC87114 did not have direct adverse effects or enhance the activity of VP16 on the proliferation and survival of normal haemopoietic progenitors. Overall, our results identify the p110delta isoform as a potential therapeutic target in AML and support a clinical approach to use isoform-selective over broad-spectrum PI3K inhibitors.

A polypeptide from Chlamys farreri abolishes UV-induced apoptosis in murine thymocytes in vitro

Previously we reported that a polypeptide from Chlamys farreri (PCF) was a potent photoprotective agent against ultraviolet (UV) irradiation in vitro. To understand the mechanism by which PCF protects cells from irradiation, we studied anti-apoptotic effects of PCF against UV irradiation on the murine thymocytes in vitro. MTT and flow cytometric analysis assays showed that 2h pretreatment with PCF completely abolished UV induced cell death. TEM examination showed that PCF fully protected the ultrastructure of thymocytes exposed to UV irradiation. Lipid peroxidation and intracellular reactive oxygen species assays indicated that PCF efficiently blocked production of reactive oxygen intermediates induced by UV irradiation. Further, PCF protected UV-irradiated thymocytes from losing mitochondrial transmembrane potential and DNA fragmentation. Based on these observations we propose that PCF is a potent anti-apoptotic factor, which protects cells from irradiation at multiple steps.

Human lung fibroblast response to NGF, IL-1beta, and dexamethsone

It has been shown that lung mast cells, eosinophils, and fibroblasts are receptive to the action of nerve growth factor (NGF) and that NGF is released in to the bloodstream of subjects affected by allergic inflammatory response. The role of NGF in lung inflammatory disorders is unclear because there is evidence suggesting that NGF can be involved in both proinflammatory and anti-inflammatory responses. Lung fibroblasts play a marked role in inflammation. In this study we investigated the effect of NGF, interleukin 1beta (II-1beta), and dexamethasone (DEX) on human lung fibroblasts in vitro. We found that II-1beta, but not NGF, promotes fibroblasts' survival and that NGF stimulates trkA receptor expression, down regulates TFG-alpha, and has no effect on TNF-beta immunoreactivity. Moreover, DEX exerts different effects on NGF release by fibroblasts pre-exposed to II-1gamma. Our findings suggest that the NGF released by lung fibroblast during inflammation is not associated with the increase of proinflammatory factors such as TNF-alpha and II-1beta.

Cytotoxicity studies of chromium(III) complexes on human dermal fibroblasts

The cytotoxicity of certain Cr(III) complexes, such as [Cr(salen)(H(2)O)(2)](+), [Cr(edta)(H(2)O)](-), [Cr(en)(3)](3+), [Cr(ox)(3)](3-), [Cr(pic)(3)], and CrCl(3), which differ in ionic character and ligand environment in human dermal skin fibroblasts, has been studied. After 72 h of exposure to 100 microM doses of chromium(III) complexes, the order in which the complexes had an inhibitory effect on cell viability was [Cr(en)(3)](3+) > [Cr(salen)(H(2)O)(2)](+) > [Cr(ox)(3)](3-) > [Cr(edta)(H(2)O)](-) > [Cr(pic)(3)] > CrCl(3). Based on viability studies it was confirmed that [Cr(en)(3)](3+), a triply charged cation, inhibits cell proliferation, and therefore, it was chosen to carry out further investigations. [Cr(en)(3)](3+), at a dose of 50 microM, was found to bring about surface morphological changes, evidenced by cellular blebbing and spike formation accompanied by nuclear damage. TEM analysis revealed substantial intracellular damage to fibroblasts in terms of the formation of apoptotic bodies and chromatin condensation, thus reflecting cell death. FACS analysis further revealed DNA damage by formation of a sub-G(1) peak with 84.2% DNA as aneuploid DNA and arrest of the G(2) / M phase of the cell cycle. Cellular DNA damage was confirmed by agarose gel electrophoresis with the characteristic appearance of a DNA streak in DNA isolated from [Cr(en)(3)](3+)-treated fibroblasts. The proposed mechanism suggests the plausible role of Cr(V), formed as a result of oxidation of Cr(III) by cellular oxidative enzymes, in the cytotoxic response. Consequently, any Cr(III) complex that is absorbed by cells and can be oxidized to Cr(V) must be considered a potential carcinogen. This has potential implications for the increased use of Cr(III) complexes as dietary supplements and highlights the need to consider the cytotoxicity and genotoxicity of a variety of Cr(III) complexes and to understand the potential hazards of Cr(III) complexes encountered in research laboratories.

2004 Dr. Gary J. Becker Young Investigator Award: Relative thermosensitivity of cytotoxic drugs used in transcatheter arterial chemoembolization

PURPOSE

Large hepatocellular carcinoma tumors are being treated increasingly with a combination of transcatheter arterial chemoembolization (TACE) and radiofrequency (RF) ablation. However, the high temperatures reached during RF ablation may reduce the cytotoxic effects of antineoplastic agents, but this has not been studied. Therefore, in the present study, the relative thermosensitivity of cytotoxic drugs commonly used in TACE was studied.

MATERIALS AND METHODS

The relative cytotoxic effects of cisplatin, doxorubicin HCl, and mitomycin on the growth of human colon HT29 and lung A549 adenocarcinoma cells before and after heating each drug in solution was determined from the standpoints of different durations of exposure (15, 30, 60, 90, and 120 minutes) at a fixed temperature (120 degrees C) and exposure to different temperatures (60 degrees C, 80 degrees C, 100 degrees C, and 120 degrees C) for a fixed period of time (2 hours). After 72 hours of exposure of the cells to each drug, relative cell growth inhibition was assessed by MTT assay, and 50% inhibitory concentration (IC(50)) values were calculated for each cytotoxic agent. Finally, the heat-dependent degradation of mitomycin and doxorubicin was analyzed with use of tandem electrospray mass spectrometry.

RESULTS

The relative cytotoxic activities (shown by cell growth inhibition and IC(50) values) of cisplatin, doxorubicin, and mitomycin heated to 120 degrees C for 2 hours decreased by factors of 1.35 (range, 1-1.75), 9.5 (range, 8.5-10.5), and 7.05 (range, 3.5-12), respectively. The cytotoxic activities of doxorubicin and mitomycin continued to decrease with incremental increases in temperature. Similarly, with incremental increases in the duration of exposure to heat, the cytotoxic activities of doxorubicin and mitomycin decreased. Mass spectrometric analysis of residual drug content showed that a 2-hour exposure to a temperature of 120 degrees C caused doxorubicin and mitomycin to degrade by 95% and 84%, respectively.

CONCLUSIONS

The cytotoxicity of cisplatin is not affected by heat. The cytotoxicities of doxorubicin and mitomycin are reduced by high temperature and duration of exposure to heat. Although degradation of cytotoxicity starts at 60 degrees C and after 30 minutes of exposure to heat, statistically significant changes are encountered at 100 degrees C and after 90 minutes of exposure.

In vitro human ependymoblastoma cells differentiate after exposure to nerve growth factor

Nerve Growth Factor (NGF) has a prominent action on immature crest-derived nerve cells and on differentiation and survival of neurons in central and peripheral nervous system. NGF is produced by a variety of neuronal and non-neuronal cells, including neoplastic cells. Its role in tumor cells is largely unknown and controversial. The aim of the present study was to investigate the effect of NGF on brain neoplastic cells using primary cultures from ependymoblastoma (EP) tissue. Human EP tissues were cultured to obtain in vitro cells and their structural, biochemical, and molecular responses to NGF were investigated. The results showed that under basal conditions, human EP cells are characterized by low presence of high-affinity NGF-receptors. Time-course and dose-response studies revealed that EP cells undergo differentiation after exposure to NGF. Our findings showed that in human EP cells, NGF exerts a marked action on differentiation rather than proliferation.