Neuroprotective activity of 2-amino-1,3,4-thiadiazole derivative 4BrABT--an in vitro study

4BrABT (2-(4-Bromophenylamino)-5-(2,4-dihydroxyphenyl)-1,3,4-thiadiazole) is a compound known for its interesting in vitro anticancer profile. 4BrABT inhibited proliferation and motility of several cancer cell lines in concentrations which were not toxic to normal cells. A major problem associated with cancer chemotherapy, but also caused by environmental factors such as pesticides, is neurotoxicity. Therefore, the aim of the presented study was an in vitro evaluation of the neuroprotective activity of this compound. 4BrABT activity (1-100 μM) was tested in cultures of mouse neurons, rat astrocytes and rat oligodendrocytes. A possible protective action of the compound in different neurodegenerative models, as serum deprivation (SD), excitotoxicity (presence of 500 μM glutamate in culture medium), as well as cisplatin toxicity (astroglia--50 μM and oligodendroglia--100 μM) was investigated. Cell viability in the tested cultures was assessed with the use of LDH and MTT methods. Moreover, 4BrABT ability to prevent the cisplatin-induced apoptosis in astrocyte and oligodendrocyte cultures was analysed after Hoechst 33342 fluorostaining. The obtained results indicate that 4BrABT was not toxic to neurons, astrocytes and oligodendrocytes. Moreover, a decrease in the neuronal LDH level was observed, which may suggest the ability of 4BrABT to act as a trophic agent. Furthermore, the protective action of the studied compound was shown in neuronal cultures exposed to neurotoxic conditions (presence of glutamate and trophic stress) and in cisplatin-treated astrocytes and oligodendrocytes. The expression of anticancer and neuroprotective activity raises hopes for the potential use of 4BrABT as a safe anticancer drug, or neuroprotective agent in chemotherapy-associated neurotoxicity.

Alpha-ketoglutarate (AKG) inhibits proliferation of colon adenocarcinoma cells in normoxic conditions

BACKGROUND AND OBJECTIVE

Alpha-ketoglutarate (AKG), a key intermediate in Krebs cycle, is an important biological compound involved in the formation of amino acids, nitrogen transport, and oxidation reactions. AKG is already commercially available as a dietary supplement and its supplementation with glutamine, arginine, or ornithine alpha-ketoglutarate has been recently considered to improve anticancer immune functions. It is well documented that AKG treatment of Hep3B hepatoma cells in hypoxia induced HIF-alpha (hypoxia-inducible factor) degradation and reduced vascular endothelial growth factor (VEGF) synthesis. Moreover, AKG showed potent antitumor effects in murine tumor xenograft model, inhibiting tumor growth, angiogenesis, and VEGF gene expression. However, the mechanisms of its anticancer activity in normoxia have not been examined so far.

RESULTS

Here, we report that in normoxia, AKG inhibited proliferation of colon adenocarcinoma cell lines: Caco-2, HT-29, and LS-180, representing different stages of colon carcinogenesis. Furthermore, AKG influenced the cell cycle, enhancing the expression of the inhibitors of cyclin-dependent kinases p21 Waf1/Cip1 and p27 Kip1. Moreover, expression of cyclin D1, required in G1/S transmission, was decreased, which accompanied with the significant increase in cell number in G1 phase. AKG affected also one the key cell cycle regulator, Rb, and reduced its activation status.

CONCLUSION

In this study for the first time, the antiproliferative activity of AKG on colon adenocarcinoma Caco-2, HT-29, and LS-180 cells in normoxic conditions was revealed. Taking into consideration an anticancer activity both in hypoxic and normoxic conditions, AKG may be considered as a new potent chemopreventive agent.

Identification of an Hsp90 mutation that selectively disrupts cAMP/PKA signaling in Saccharomyces cerevisiae

The molecular chaperone Hsp90 cooperates with multiple cochaperone proteins as it promotes the folding and activation of diverse client proteins. Some cochaperones regulate the ATPase activity of Hsp90, while others appear to promote Hsp90 interaction with specific types of client proteins. Through its interaction with the adenylate cyclase Cyr1, the Sgt1 cochaperone modulates the activity of the cAMP pathway in Saccharomyces cerevisiae. A specific mutation in yeast Hsp90, hsc82-W296A, or a mutation in Sgt1, sgt1-K360E, resulted in altered transcription patterns genetically linked to the cAMP pathway. Hsp90 interacted with Cyr1 in vivo and the hsc82-W296A mutation resulted in reduced accumulation of Cyr1. Hsp90-Sgt1 interaction was altered by either the hsc82-W296A or sgt1-K360E mutation, suggesting defective Hsp90-Sgt1 cooperation leads to reduced Cyr1 activity. Microarray analysis of hsc82-W296A cells indicated that over 80 % of all transcriptional changes in this strain may be attributed to altered cAMP signaling. This suggests that a majority of the cellular defects observed in hsc82-W296A cells are due to altered interaction with one specific essential cochaperone, Sgt1 and one essential client, Cyr1. Together our results indicate that specific interaction of Hsp90 and Sgt1 with Cyr1 plays a key role in regulating gene expression, including genes involved in polarized morphogenesis.

Kinetic studies of the effects of Temodal and quercetin on astrocytoma cells

The aim of the present study was to investigate the kinetics of the effects exerted by Temodal and quercetin on the survival of the human astrocytoma MOGGCCM cell line. Our results indicate that quercetin was toxic and induced necrosis, whereas Temodal induced autophagy-mediated cell death most effectively. The amount of cell death directly correlated with drug concentration and length of exposure. During combined administration of both drugs, Temodal attenuated the cytotoxic effects of quercetin. Combinations of both drugs were effective in inducing programmed cell death, but the type of cell death was concentration-dependent. Co-administration of Temodal (100 μM) with a low quercetin concentration (5 μM) resulted in a very significant induction of autophagy; however, after treatment with quercetin at a higher concentration (30 μM), apoptosis became the primary mechanism of cell death. The sequence of drug administration was also important. The highest number of dead cells was observed after simultaneous administration of both drugs or after pre-incubation with Temodal followed by treatment with quercetin. Apoptosis was identified through activation of the mitochondrial pathway including cleavage of caspase-3 and release of cytochrome c. Autophagy was identified through increased levels of LC3II. Our results indicate that Temodal and quercetin are synergistic inducers of programmed cell death, better together than applied separately. This drug combination appears to be a potent and promising therapeutic relevant to the treatment of gliomas.

Kynurenic acid synthesis and kynurenine aminotransferases expression in colon derived normal and cancer cells

BACKGROUND

Kynurenic acid (KYNA), a tryptophan metabolite, was found in human saliva, gastric juice, bile, pancreatic juice and mucus of rat small intestine.

METHODS

KYNA content in mucus aspirated from human caecum or colon ascendens and KYNA production in colon epithelial and cancer cells were determined using HPLC. Moreover, biological properties of KYNA and kynurenine aminotransferases (KATs) expression in colon epithelial and colon cancer cells were studied.

RESULTS

Considerably higher KYNA concentration was detected in samples from patients diagnosed with colon carcinoma (269.40 ± 107.00 pmol/ml, N = 4), Adenoma tubulovillosum (200.50 ± 36.72, N = 10) or Adenoma tubulare (243.50 ± 38.09, N = 9) than in control group (82.22 ± 7.61 pmol/ml, N = 30). Moreover, colon epithelium CCD 841 CoTr cells actively synthesized KYNA in a concentration- and time-dependent manner. This process was decreased by aminooxyacetic acid and L-glutamate in opposite to 4-aminopyridine treatment. Interestingly, KYNA production in colon cancer cells (HT-29 1.39 ± 0.27, LS-180 1.18 ± 0.15 and Caco-2 4.21 ± 0.30 pmol/1 x 10(5) cells/2 h) was considerably higher in comparison to normal colon epithelial cells (0.70 ± 0.07 pmol/1 x 10(5) cells/2 h). However, KATs I and II were expressed at similar level in both colon epithelium and cancer cells. Furthermore, KYNA exerted an antiproliferative effect at higher micro- and millimolar concentrations against colon cancer cells with the IC(50) of 0.9, 0.2 and 1.2 mM for HT-29, LS-180 and Caco-2 cells, respectively.

CONCLUSION

Summarizing, this is the first report presenting KYNA synthesis and KAT expression in colon derived normal and cancer cells.

Antiproliferative activity of melanoidins isolated from heated potato fiber (potex) in glioma cell culture model

Potex constitutes a potato fiber preparation widely used as an ingredient to meat and bakery products which thermal treatment results in creation of new compounds. Melanoidins are high molecular weight brown end products of Maillard reaction, and few data presenting tumor cell growth inhibiting activity of melanoidins have been reported. Thus, in present study we utilized water extract of Potex roasted (180 °C for 2 h), whose chemical characterization revealed the presence of melanoidin complexes. Heated Potex extract inhibited C6 glioma cell proliferation in a dose-dependent manner measured by MTT method. High molecular weight components present in initial extract were responsible for stronger antiproliferative effect compared with low molecular weight fraction. Impaired MAPK (mitogen-activated protein kinase) and Akt signaling was found in cells treated with the extract. Moreover, flow cytometry analyses revealed the extract to induce G1/S arrest in glioma cells. Simultaneously, Western blot analysis showed elevated levels of p21 protein with concomitant decrease of cyclin D1. In conclusion, observed antiproliferative activity of melanoidins present in heated Potex was linked to disregulated MAPK and Akt signaling pathways, as well as to cell cycle cessation. These results suggest potential application of Potex preparation as a functional food ingredient and chemopreventive agent.

Temozolomide, quercetin and cell death in the MOGGCCM astrocytoma cell line

The aim of the present study was to investigate the effect of Temozolomide (an alkylating chemotherapeutic agent) and quercetin (natural flavonoid) on cell death in the human astrocytoma cell line MOGGCCM (WHO grade III). Our results indicate that Temozolomide induces autophagy, while quercetin promotes severe necrosis in the cell line in a manner dependent on the drug concentration. We demonstrated for the first time that combinations of both drugs were much more effective in programmed cell death induction in glioma cells. At a low (5muM) drug concentration, quercetin potentiated a pro-autophagic effect of Temozolomide, while after treatment with a higher drug concentration (30muM), autophagy switched to apoptosis. Temozolomide attenuated the toxic effect of quercetin. Apoptosis was mediated by the mitochondrial pathway and the activation of caspase 3 and cytochrome C release, but no changes in caspase 8 expression was observed. It was accompanied by decreased mitochondrial membrane potential and inhibition of Hsp27 and Hsp72 expression. Autophagy was correlated with an increased level of LC3II. Temozolomide and quercetin also inhibited migratory phenotype of MOGGCCM cells and changed the nuclei morphology from a circular to an irregular shape. Our results indicate that quercetin acts in synergy with Temozolomide and when used in combination rather than in separate pharmacological application, both drugs are more effective in programmed cell death induction. Temozolomide administered with quercetin seems to be a potent and promising combination which might be useful in glioma therapy.

Separation of an aqueous extract Inonotus obliquus (Chaga). A novel look at the efficiency of its influence on proliferation of A549 human lung carcinoma cells

Aqueous extract of Inonotus obliquus was hydrolyzed in dilute hydrochloric acid. The products were extracted applying organic solvents, and separated chromatographically on a silica gel-packed column. Eluted fractions were analyzed by means of GC-MS. The presence of hydrocarbons, alcohols, phenols and various carbonyl compounds in analyzed fractions has been detected and quantified. Preliminarily experiments on the influence of certain separated samples on the proliferation of A549 human lung carcinoma cells were performed. Therefore, we hypothesize that the major antiproliferative effects are related to the presence of benzaldehyde, which is a benzyl alcohol metabolite formed in situ in the cells culture with the yield moderated by the presence of trace amounts of "high molecular mass compounds".

The T/G mutation in exon 8 of hMSH2 gene in the sporadic colon cancer patients

The DNA mismatch repair (MMR) system guards against genomic instability, therefore the mutations in the human MMR genes cause the majority of the hereditary nonpolyposis colorectal cancer (HNPCC) and a small percentage of the sporadic colon cancer. hMSH2 is one of MMR genes involved in the correction of mispairing during replication and its mutations are associated with both--microsatellite instability and the hereditary and sporadic colon tumourgenesis. The aim of this study was to analyse the T/G mutation (codon 458) in exon 8 of hMSH2 gene in the sporadic colon cancer cells. We also examined the relationship between the T/G mutation of hMSH2 gene, and the selected prognostic factors such as Dukes' stage, histological grade and lymph node metastasis. We analysed samples of tumour from 75 patients with sporadic colorectal cancers. The mutation in the hMSH2 gene ware determined by the RFLP-PCR. We found T/G mutation in exon 8 of hMSH2 gene in 5 patients (6,7%). There was no statistically significant difference between this mutation and selected clinical parameters. The results of our studies revealed that mutations of hMSH2 gene may lead to development of colorectal cancer. No dependence between the mutation of hMSH2 gene and clinical parameters, suggests that the mutation of hMSH2 gene may have a critical significance for the first steps of carcinogenesis in colon epithelial.

[Genetics analysis of microsatellite instability in patients from hereditary nonpolyposis colorectal cancer (HNPCC) families]

Microsatellite instability (MSI) is due to defective DNA mismatch repair and is characteristic of HNPCC tumours.

THE AIM

The role of MSI in familial predisposition to colorectal cancer was investigated in this study by microsatellite analysis among familial cases.

MATERIAL AND METHODS

PCR-based microsatellite analysis was performed in blood obtained from 30 members from HNPCC families. Blood samples age matched healthy individuals (n = 28) served as control. MSI was studied at five loci containing single- or dinucleotide repeat sequences and mapping to different chromosomal locations: BAT-25 (at locus 4q12), BAT-26 (2p16), D2S123 (2p16-p21), D5S346 (5q21-q22) and D17S250 (17q11.2-q12).

RESULTS

MSI frequency was higher in member of HNPCC families (40%) than in control (10.7%) cases. Out of the 30 samples tested, 12 were found to be MSI positive, 9 MSI high and 3 MSI low.

CONCLUSION

The present study suggest that microsatellite instability seem to be a risk factor of colorectal cancer in subjects belonged to HNPCC families with high incidence of this cancer.

Analysis of microsatellite instability and BRCA1 mutations in patients from hereditary nonpolyposis colorectal cancer (HNPCC) family

Susceptibility to colorectal cancer appears to be linked to germ-line mutations in genes causing various familial cancer syndromes. The objectives of this study were to determine microsatellite instability and the frequency of BRCA1 germ-line mutations in patients with family history of cancer. The study population consisted of 30 patients from HNPCC family. Patients completed a family history questionnaire and provided blood for mutation analysis. Seven out of 30 investigated samples (23%) were found to be MSI-positive, 6 MSI-high and 1 MSI-low. Ex20insC and ExII17delA mutations of BRCA1 gene were identified in MSI-positive samples from HNPCC families. In the present study one Ex20insC mutation and two ExII17delA mutations were detected only in MSI-high samples. Genetic alterations seem to be a risk factor of colorectal cancer in subjects belonging to HNPCC families with high incidence of this cancer. The lack of detectable germ-line mutations in most cases suggests that there are probably additional, as yet unidentified genes predisposing to this disease.

Genetic analysis of microsatellite markers in patients from hereditary nonpolyposis colorectal cancer (HNPCC) families

AIM

Microsatellite instability (MSI) is due to defective DNA mismatch repair (MMR) and is characteristic of hereditary nonpolyposis colorectal cancer (HNPCC) tumors. The role of MSI in familial predisposition to colorectal cancer was investigated in this study by both microsatellite analysis and mutation screening of the two major MMR genes MLH1 and MSH2 among familial cases.

METHODS

PCR-based microsatellite analysis was performed in blood obtained from 30 members from HNPCC families. Blood samples age matched healthy individuals (n = 28) served as control. MSI was studied at five loci containing single- or dinucleotide repeat sequences and mapping to different chromosomal locations: BAT-25 (at locus 4q12), BAT-26 (2p16), D2S123 (2p16-p21), D5S346 (5q21-q22) and D17S250 (17q11.2-q12).

RESULTS

MSI frequency was higher in member of HNPCC families [7/30 (23%)] than in control [3/28 (10.7%)] cases. Two MLH1 and one MSH2 mutations were identified in 7 MSI positive samples from HNPCC families. MLH1/MSH2 mutations were only in MSI high samples detected.

CONCLUSION

Genetic alterations seem to be a risk factor of colorectal cancer in subjects belonged to HNPCC families with high incidence of this cancer.

Risk factors in the recurrence of the colorectal cancer

Traditionally, the clinical outcome of colorectal cancer patients may be predicted by pathological staging by either Dukes staging or the UICC-TNM system. However, some of Dukes stage A (approximately 10% of patients) and Dukes B patients (30-40%) will develop local recurrence or distant metastasis years after receiving standard surgical treatments. Therefore it is important to find some other indicators that can predict for recurrence so that we can screen for high-risk early-stage patients who may need preventive chemotherapy or other adjuvant therapy. The aim of this study is determination of risk factor for local recurrence in rectal cancer. In this study there has been used and summarized also research records and publications from different clinical hospitals according to actual international literature. Part of elements connected with patient, tumor and genetic and immunological factors remains independent on curative procedures. However better investigation these factors might affect on therapy, frequency of follow-up examinations, and help to detect recurrence at very early phase. Concomitant treatment factors are able to be moderate by surgeons and therapeutics. Therefore precise definition of risk factors might be helpful in decrease recurrence rate in patients with rectal cancer.

New approaches to the treatment of anal fissure

According to Antropoli, pathologies of the anal canal are extremely common. About 30 to 40 percent of the population suffers from proctologic pathologies at least once in their lives. In most cases they are more annoying than dangerous. Anal fissure (AF) was recognized as a clinical entity in 1934. It is a longitudinal defect of the anal canal mucosa and anoderm extending usually from the dentate line to the external verge of the anal canal. This defect exposes the lower half or even most of the fibres of internal anal sphincter. AF is almost always accompanied by extensive tension of this muscle. Anal fissures affect all age groups but predominantly occur in the 3rd and 4th decades of life (2, 8, 23). Gathright states that fissure disease causes from 6 to 15% of office visits and 10% of operative procedures in a colorectal practice. The etiology of anal fissure has only been partially explained and remains controversial although spasm of the internal anal sphincter has been recognized to play a main role in the pathogenesis of this disease. Recent studies have cast new light on the pathogenesis of anal fissures.

Treatment of locally aggressive well-differentiated thyroid cancer

The object of this study, conducted at Unicamp between 1988 and 1998, was to evaluate retrospectively the outcome of patients treated for locally aggressive well-differentiated thyroid carcinomas (LATC). Nineteen (42%) of 45 patients with thyroid carcinomas were considered to have LATC. The preoperative diagnosis of carcinoma was made either by fine needle aspiration biopsy (15 patients) or during surgery (4 patients). The usual prognostic factors were analyzed and classified according to risk groups. Survival was evaluated using the Kaplan-Meier method. Most of the patients were female (73%), with a mean age of 48 years. Eighteen (95%) had papillary carcinomas. Four patients were classified as high risk (21%) and the remaining 15 (79%) as intermediate risk. All patients underwent total thyroidectomy and different types of neck dissections. The structures invaded by tumors were strap muscles and trachea (four cases); recurrent nerve and larynx (three cases); manubrium, esophagus, and jugular vein (two cases); and hyoid bone and pharynx (one case). Complete tumor resection was carried out according to the extent of local invasion; no postoperative deaths resulted. Details of the procedures are provided in Table 4 and in the Discussion. Postoperative radioactive iodine treatment was used in 15 patients (79%). A mean follow-up (+/-7 years) revealed 13 (68%) patients without disease, 4 patients (21%) alive with controlled systemic disease, and 2 (11%) deaths from distant metastasis. The Kaplan-Meir survival curve was comparable with other studies in the literature. This study found that the frequency of LATC (42%) was higher than in most studies. Aggressive surgical therapy to treat these tumors is compatible with a low recurrence rate and long-term survival in a significant proportion of patients.

Ginger: history and use

Ginger is well known in the form of ginger sticks or ginger ale. If these are consumed during travel, the traveler imbibes, albeit subconsciously, a healing plant for motion sickness. The efficacy of ginger rhizome for the prevention of nausea, dizziness, and vomiting as symptoms of motion sickness (kinetosis), as well as for postoperative vomiting and vomiting of pregnancy, has been well documented and proved beyond doubt in numerous high-quality clinical studies. The use of this ancient medicine for gastrointestinal problems (stimulation of digestion) has been given scientific approval. Today, medicinal ginger is used mainly for prevention of the symptoms of travel sickness.

Objectivation of latent psychoses

A method--the flicker-frequency-analysis (FFA)--is reported by which it is possible to differentiate latent psychoses with neurotic sensation- and behaviour-disorders and "neuroses". The consecutive early treatment prevents irreversible lesions.