Changes in the Proteome Profile of A549 Cells Following Helichrysetin-Induced Apoptosis Suggest the Involvement of DNA Damage Response and Cell Cycle Arrest-Associated Proteins

Our previous findings demonstrated that Helichrysetin possessed promising anti-cancer activity. It was able to induce apoptosis in the A549 cell line. However, its mechanism of action is unknown. The present study aimed to unravel possible underlying molecular mechanisms of helichrysetin-induced apoptosis in A549 (human lung carcinoma) cells using comparative quantitative proteomics (iTRAQ labeled), followed by an exhaustive bioinformatics analysis. Our results suggested that DNA damage response (DDR) and cell cycle arrest were responsible for lung cancer cell death with helichrysetin treatment. Among proteins that changed in abundance were Nrf2 and HMOX1. They are oxidative stress-related proteins and were increased in abundance. BRAT1 was also increased in abundance, suggesting an increase in DNA damage repair, indicating the occurrence of DNA damage due to oxidative stress. However, several essential DDR downstream proteins such as p-ATM, BRCA1, FANCD2, and Rb1 that would further increase DNA damage were found to be dramatically decreased in relative abundance. Cell cycle-related proteins, p53, p21, and cyclin D1, were increased while cyclin A, cyclin E, and cdk2 were decreased. This is predicted to facilitate S-phase arrest. Furthermore, excessive DNA damage and prolonged arrest would in turn result in the induction of mitochondrial-mediated apoptosis. Based on these observations, we postulate that the effects of helichrysetin were in part via the suppression of DNA damage response which led to DNA damage and prolonged cell cycle arrest. Subsequently, this event initiated mitochondrial-mediated apoptosis in A549 lung cancer cells.

Comparative proteomics reveals that YK51, a 4-Hydroxypandurantin-A analogue, downregulates the expression of proteins associated with dengue virus infection

Dengue is endemic throughout tropical and subtropical regions of the world. Currently, there is no clinically approved therapeutic drug available for this acute viral infection. Although the first dengue vaccine Dengvaxia has been approved for use in certain countries, it is limited to those without a previous dengue infection while the safety and efficacy of the vaccine in those elderly and younger children still need to be identified. Therefore, it is becoming increasingly important to develop therapeutics/drugs to combat dengue virus (DENV) infection. YK51 is a synthetic analogue of 4-Hydroxypandurantin A (a compound found in the crude extract of the rhizomes of Boesenbergia rotunda) that has been extensively studied by our research group. It has been shown to possess outstanding antiviral activity due to its inhibitory activity against NS2B/NS3 DENV2 protease. However, it is not known how YK51 affects the proteome of DENV infected cells. Therefore, we performed a comparative proteomics analysis to identify changes in protein expression in DENV infected HepG2 cells treated with YK51. Classical two-dimensional gel electrophoresis followed by protein identification using tandem mass spectrometry was employed in this study. Thirty proteins were found to be down-regulated with YK51 treatment. In silico analysis predicted that the down-regulation of eight of these proteins may inhibit viral infection. Our results suggested that apart from inhibiting the NS2B/NS3 DENV2 protease, YK51 may also be causing the down-regulation of a number of proteins that may be responsible in, and/or essential to virus infection. However, functional characterization of these proteins will be necessary before we can conclusively determine their roles in DENV infection.

Xanthohumol induces apoptosis and S phase cell cycle arrest in A549 non-small cell lung cancer cells

BACKGROUND

Xanthohumol, a major prenylated chalcone found in female hop plant, Humulus lupulus, was reported to have various chemopreventive and anti-cancer properties. However, its apoptotic effect on human alveolar adenocarcinoma cell line (A549) of non-small cell lung cancer (NSCLC) was unknown.

OBJECTIVE

This study aimed to investigate the effects of xanthohumol on apoptosis in A549 human NSCLC cells.

MATERIALS AND METHODS

A549 cell proliferation was determined by sulforhodamine B assay. Morphological changes of the cells were studied via phase contrast and fluorescent microscopy. Induction of apoptosis was assessed by Annexin-V fluorescein isothiocyanate/propidium iodide (Annexin V-FITC/PI) staining, DNA fragmentation (TUNEL) assay mitochondrial membrane potential assay, cell cycle analysis, and caspase activity studies.

RESULTS

Xanthohumol was found to decrease cell proliferation in A549 cells but had relatively low cytotoxicity on normal human lung fibroblast cell line (MRC-5). Typical cellular and nuclear apoptotic features were also observed in A549 cells treated with xanthohumol. Onset of apoptosis in A549 cells was further confirmed by externalization of phosphatidylserine, changes in mitochondrial membrane potential, and DNA fragmentation in the cells after treatment. Xanthohumol induced accumulation of cells in sub G1 and S phase based on cell cycle analysis and also increased the activities of caspase-3, -8, and -9.

CONCLUSION

This work suggests that xanthohumol as an apoptosis inducer, may be a potent therapeutic compound for NSCLC.

Posterior lumbar apophyseal ring fractures in adolescents: a report of four cases

Posterior lumbar apophyseal ring fractures are rare in adolescents. We report 4 such cases in Chinese adolescents. Two of the patients had a slipped capital femoral epiphysis; 3 of them were overweight/obese. All presented with low back pain and radicular pain. Apophyseal fractures of the upper lumbar spine usually involve the lower end plate, whereas those of the lumbar sacral spine usually involve the upper end plate. The radiological features and pathophysiology are discussed. Two of the patients were treated with laminotomy and diskectomy after conservative treatment failed. All patients had complete resolution of their neurological deficits at a mean follow-up of 2 years. Despite its benign nature, long-term follow-up is necessary to define the natural course and prognosis of the disease. A high index of suspicion is needed to diagnose these fractures in adolescents.

Minimally invasive repair of ruptured Achilles tendon

OBJECTIVE

To study the clinical outcomes of minimally invasive repair of ruptured Achilles tendon.

DESIGN

Retrospective study.

SETTING

Orthopaedics and Traumatology Department of a public hospital in Hong Kong.

PATIENTS

Fifteen consecutive patients admitted to the hospital from August 2002 to April 2005 with closed Achilles tendon rupture, had it repaired by a minimally invasive method. Parameters including patient epidemiology, nature of injuries, and isometric force measurement of ankle plantar flexion were recorded to justify the effectiveness of the Achilles tendon repair.

RESULTS

Isometric peak force measurement of ankle plantar flexion 1 year after injury showed an average regain of 95% of the calf muscle strength, compared to the normal side. All wounds healed well, without major complications such as deep infection, sural nerve injury, or re-rupture of the Achilles tendon. All patients were able to resume their pre-injury activity level and previous occupation.

CONCLUSION

This minimally invasive surgical technique using the Achillon suture guide produces encouraging results in the operative management of ruptured Achilles tendon.

Genetic polymorphism of the CYP2E1 gene and susceptibility to Parkinson's disease in Taiwanese

Cytochrome p450IIE1 (CYP2E1), an ethanol-inducible cytochrome p450 enzyme, is expressed in the basal ganglia and is probably involved in the activation of neurotoxicants, producing free radical metabolites and resulting in oxidative stress. To examine the association between CYP2E1 polymorphism and the risk of Parkinson's disease (PD), we performed a case-control study on a large population of Taiwanese PD patients, focusing especially on early-onset PD patients (onset at, or before, the age of 50). Two hundred and thirty-four PD patients and 251 age- and sex-matched controls were recruited. A much higher frequency of the uncommon c2 allele was seen in our control subjects than in Caucasians (0.23 vs. 0.02). There were no significant differences between PD patients and controls in the distribution of either allelic or genotype frequencies. Our results suggest that CYP2E1 is not a major or independent determinant in the occurrence of PD in Taiwanese.

Determination and pharmacokinetic profile of omeprazole in rat blood, brain and bile by microdialysis and high-performance liquid chromatography

The disposition and biliary excretion of omeprazole was investigated following i.v. administration to rats at 10 mg/kg. We used a microdialysis technique coupled to a validated microbore HPLC system to monitor the levels of protein-unbound omeprazole in rat blood, brain and bile, constructing the relationship of the time course of the presence of omeprazole. Microdialysis probes were simultaneously inserted into the jugular vein toward right atrium, the brain striatum and the bile duct of the male Sprague-Dawley rats for biological fluid sampling after the administration of omeprazole (10 mg/kg) through the femoral vein. The concentration-response relationship from the present method indicated linearity (r2>0.995) over a concentration range of 0.01-50 microg/ml for omeprazole. Intra-assay and inter-assay precision and accuracy of omeprazole fell well within the predefined limits of acceptability. Following omeprazole administration, the blood-to-brain coefficient of distribution was 0.15, which was calculated as the area under the concentration versus time curve (AUC) in the brain divided by the AUC in blood (k=AUCbrain/AUCblood). The blood-to-bile coefficient of distribution (k=AUCbile/AUCblood) was 0.58. The decline of unbound omeprazole in the brain striatum, blood and bile fluid suggests that there was rapid exchange and equilibration between the compartments of the peripheral and central nervous systems. In addition, the results indicated that omeprazole was able to penetrate the blood-brain barrier and undergo hepatobiliary excretion.

Phase I clinical trial of curcumin, a chemopreventive agent, in patients with high-risk or pre-malignant lesions

Curcumin (diferuloylmethane), a yellow substance from the root of the plant Curcuma longa Linn., has been demonstrated to inhibit carcinogenesis of murine skin, stomach, intestine and liver. However, the toxicology, pharmacokinetics and biologically effective dose of curcumin in humans have not been reported. This prospective phase-I study evaluated these issues of curcumin in patients with one of the following five high-risk conditions: 1) recently resected urinary bladder cancer; 2) arsenic Bowen's disease of the skin; 3) uterine cervical intraepithelial neoplasm (CIN); 4) oral leucoplakia; and 5) intestinal metaplasia of the stomach. Curcumin was taken orally for 3 months. Biopsy of the lesion sites was done immediately before and 3 months after starting curcumin treament. The starting dose was 500 mg/day. If no toxicity > or = grade II was noted in at least 3 successive patients, the dose was then escalated to another level in the order of 1,000, 2,000, 4,000, 8,000, and 12,000 mg/day. The concentration of curcumin in serum and urine was determined by high pressure liquid chromatography (HPLC). A total of 25 patients were enrolled in this study. There was no treatment-related toxicity up to 8,000 mg/day. Beyond 8,000 mg/day, the bulky volume of the drug was unacceptable to the patients. The serum concentration of curcumin usually peaked at 1 to 2 hours after oral intake of crucumin and gradually declined within 12 hours. The average peak serum concentrations after taking 4,000 mg, 6,000 mg and 8,000 mg of curcumin were 0.51 +/- 0.11 microM, 0.63 +/- 0.06 microM and 1.77 +/- 1.87 microM, respectively. Urinary excretion of curcumin was undetectable. One of 4 patients with CIN and 1 of 7 patients with oral leucoplakia proceeded to develop frank malignancies in spite of curcumin treatment. In contrast, histologic improvement of precancerous lesions was seen in 1 out of 2 patients with recently resected bladder cancer, 2 out of 7 patients of oral leucoplakia, 1 out of 6 patients of intestinal metaplasia of the stomach, I out of 4 patients with CIN and 2 out of 6 patients with Bowen's disease. In conclusion, this study demonstrated that curcumin is not toxic to humans up to 8,000 mg/day when taken by mouth for 3 months. Our results also suggest a biologic effect of curcumin in the chemoprevention of cancer.

Heterotrimeric G-protein and signal transduction in the nematode-trapping fungus Arthrobotrys dactyloides

The fungus Arthrobotrys dactyloides produces specialized constricting rings to trap and then consume nematodes. The signal transduction pathway involved in the nematode-trapping process was examined. Mastoparan, an activator of G-protein, had a stimulatory effect on the inflation of ring cells, whereas a G-protein inhibitor, pertussis toxin, prevented ring-cell expansion. The 40-kDa G alpha of heterotrimeric G-proteins was specifically ADP-ribosylated by pertussis toxin. Using an antibody specific to the 35-kDa subunit G beta, we showed that immunogold-labeled G beta was more concentrated in ring cells than in the hyphae. In the absence of nematodes, the rings could be inflated by either pressurizing the culture in a syringe, raising intracellular Ca2+ concentrations, or adding warm water. We used these methods to reveal differences in responses to antagonists. The results support a model in which the pressure exerted by a nematode on the ring activates G-proteins in the ring cells. The activation leads to an increase in cytoplasmic Ca2+, activation of calmodulin, and finally the opening of water channels. The ring cells expand to constrict the ring and thus immobilize the nematode.

The COMT L allele modifies the association between MAOB polymorphism and PD in Taiwanese

OBJECTIVE

Reports suggest that catechol-O-methyltransferase (COMT(L/L)) (Val(158)/Met) and monoamine oxidase B (MAOB) intron 13 genotype polymorphism is associated with PD. To understand the ethnicity-specific effects of genetic polymorphism, we performed a case-control study of the association between PD susceptibility and polymorphism of MAOB and COMT, both separately and in combination, in Taiwanese.

METHODS

Two hundred twenty-four patients with PD and 197 controls, matched for age, sex, and birthplace, were recruited. MAOB and COMT polymorphism genotyping was performed by using PCR-based restriction fragment length polymorphism (RFLP) analyses. chi(2), OR, and Fisher's exact tests were used to compare differences in allelic frequencies and genotypes.

RESULTS

The MAOB G genotype (G in men and G:/G in women) was associated with a 2.07-fold increased relative risk of PD. COMT polymorphism, considered alone, showed no correlation with PD risk; however, a significant synergistic enhancement was found in PD patients harboring both the COMT(L) and MAOB G genotypes.

CONCLUSIONS

These results suggest that, in Taiwanese, PD risk is associated with MAOB G intron 13 polymorphism, and this association is augmented in the presence of the COMT(L) genotype, indicating an interaction of these two dopamine-metabolizing enzymes in the pathogenesis of sporadic PD. However, the relatively low frequencies of these combined genotypes in our study necessitates confirmation with a larger sample size.

Isolation of liver nuclei that retain functional trans-membrane transport

We have developed a method for the rapid isolation of hepatocyte nuclei, which employs gentle homogenization and centrifugation conditions, and involves minimal processing time. The purified nuclei were morphologically unaltered when observed by light and electron microscopy. No significant contamination from cytoplasm or mitochondria was detected when assessed by marker enzymes. Membrane transport function, measured as ATP-dependent calcium uptake, was intact. This isolation method was devised to be applicable to studies that involve measurement of uptake and active transport of a variety of substances by the cell nucleus.

Effects of Hemerocallis flava on motor activity and the concentration of central monoamines and its metabolites in rats

In this study, we used behavioral and biochemical methods to investigate the effects of Hemerocallis flava (Liliaceae) (abbreviated as HF) on motor activity and the concentration of monoamines in rats. The water fraction of the resuspended HF extract was most active in reducing the motility in rats. The water fraction of the HF extract enhanced the reduction of locomotor activity produced by alpha-methyl-p-tyrosine and 5-hydroxytryptophan, but it reduced the increase of locomotor activity produced by L-dopa plus benserazide and p-chlorophenylalanine. Furthermore, the water fraction of the HF extract significantly decreased the concentration of norepinepherine in the cortex and the concentration of dopamine and serotonin in the brain stem. It also increased the concentration of vanilylmandelic acid in the cortex, homovanillic acid and 5-hydroxyindole-acetic acid in the brain stem. These results suggest that the reduction of locomotor activity produced by the water fraction of HF extract may be related to the decrease in the concentration of norepinepherine in the cortex and the concentration of dopamine and serotonin in brain stem.

Comparative study of artery cuff and fat wrap in microvascular anastomosis in the rat

An artery cuff and a fat wrap placed around an anastomosis with only 4 stitches were compared to the conventional 8-10 stitches suturing technique in microvascular anastomosis: 120 vessels in 40 immature male S-D rats were used. Observations were made 1 hour, and 1, 2, 3 and 8 weeks after the repair. The newer techniques were performed faster, had shorter bleeding time and showed equivalent patency rates to the conventional technique. The artery cuff was slightly superior to the fat wrap, particularly in having fewer adhesions and a better histological picture. Clinical applications are discussed.

Fractured proximal end of the femur in the elderly--a medico-social study

278 geriatric patients with fractured proximal end of the femur were studied retrospectively 1.5-5 years (average 3.5 years) after they received treatment in two hospitals. Of the survivors 63%, 56% were totally pain-free while 15% had varying degrees of hip pain. Only 26.5% could squat fully. The physical activity was inversely proportional to the age. The widowed were doing better than the married with living husbands. Of the three methods of treatment (Austin-Moore hemiarthroplasty, plating and Ender's nailing), the hemiarthroplasty group of patients was doing the best physically. In spite of some positive X-ray findings among the different groups, corresponding clinical manifestations were not encountered.

Survey of foot deformities among 166 geriatric inpatients

A clinical survey on foot deformities among 166 geriatric inpatients was carried out. Direct measurements on hallux valgus, great toe movements, great toe deformities, lesser toe deformities, arch of the foot, callosities, ankle movements, inversion, and eversion were done by using the goniometer. A specially designed goniometer was created to measure inversion and eversion. The Harris Mat was used to study foot prints in correlation with the various deformities. About 50% of geriatric patients were found to have foot deformities of various types. This compared well with available data in literature. The target population was also checked for their symptomatology which, amazingly, was found to be really insignificant compared with the deformities present. This finding was found to be very much unlike data for Caucasian individuals with foot deformities, 50% of whom had symptoms related to pain and footwear. This major difference in the clinical presentation encourages the authors to carry on their study and, perhaps, direct cross-cultural studies in the future.