Quality control in single-molecule studies of kinesins and microtubule-associated proteins

Commercial microscopes capable of single-molecule experiments have made it simple for researchers to adopt these powerful techniques. This chapter is meant to help newcomers assess whether their data is of sufficient quality to warrant time-intensive analysis. Two problems can hamper single-molecule experiments: (1) non-specific aggregation of the proteins of interest and (2) detection thresholds from a poor microscope setup. I outline four steps that researchers can take to overcome these problems and convince themselves that they are observing bona fide single molecules.

Imaging and analysis of the microtubule cytoskeleton in giardia

Giardia intestinalis, a common parasitic protist, possesses a complex microtubule cytoskeleton critical for cellular function and transitioning between the cyst and trophozoite life cycle stages. The giardial microtubule cytoskeleton is comprised of highly dynamic and stable structures. Novel microtubule structures include the ventral disc that is essential for the parasite's attachment to the intestinal villi to avoid peristalsis. The completed Giardia genome combined with new molecular genetic tools and live imaging will aid in the characterization and analysis of cytoskeletal dynamics in Giardia. Fundamental areas of giardial cytoskeletal biology remain to be explored and knowledge of the molecular mechanisms of cytoskeletal functioning is needed to better understand Giardia's unique biology and pathogenesis.

Immunoexpression of inhibitors of apoptosis proteins and their antagonist SMAC/DIABLO in colorectal carcinoma: correlation with apoptotic index, cellular proliferation and prognosis

The inhibitors of apoptosis proteins (IAPs) act by directly blocking cleaved caspase-3 (XIAP) or the protein SMAC/DIABLO, an antagonist. The inhibition of XIAP activity or the increase of SMAC activity might improve the therapeutic response of the patients. This work evaluated the immunoexpression of IAPs and SMAC in colorectal carcinoma and their correlation with apoptotic index (AI), cellular proliferation, p53 protein immunoexpression and patient survival rate. TMA paraffin blocks were made with colorectal cancer tissue and adjacent non-tumorous mucosa of 130 patients, not submitted to radio or chemotherapy. Sections of 4 microm were processed by immunohistochemistry for survivin, XIAP, cIAP-1, cIAP-2 and SMAC, and the immunoexpression scores were obtained. They were correlated between each other and with the AI obtained by anti-cleaved caspase-3 and M30 (cleaved cytokeratin-18) antibodies, the cellular proliferation index, p53 protein immunoexpression and patient survival data. Direct correlation occurred between the four IAPs studied in tumor and non-tumorous mucosa tissues. SMAC, survivin, cIAP-1 and cIAP-2 were positively correlated with tumoral tissue AI. Cellular proliferation and p53 immunoexpression was positively correlated with XIAP, SMAC and cIAP-1 scores. Low cIAP-1 immunoexpression showed a tendency for correlation with shorter patient survival. Equilibrium between the activities of IAPs and SMAC was demonstrated by the direct correlation between their immunoexpression. Correlation between SMAC and AI confirmed the pro-apoptotic activity of this protein. XIAP showed no inverse correlation with AI. XIAP, SMAC and cIAP-1 play a role in colorectal tumorigenesis, as demonstrated by their direct correlation with cellular proliferation and p53 protein. The tendency for correlation between low cIAP-1 immunoexpression and survival might indicate a role for this protein as a prognostic marker in colorectal cancer.

Does 5-bromo-2'-deoxyuridine (BrdU) disrupt cell proliferation and neuronal maturation in the adult rat hippocampus in vivo?

5-Bromo-2'-deoxyuridine (BrdU) is frequently used as a mitotic marker in studies of cell proliferation. Recent studies have reported cytotoxic effects of BrdU on neural progenitor cells in embryonic and neonatal brains in vivo and in adult tissue studied in vitro. The present study was conducted to assess whether BrdU interferes with cell proliferation and neuronal maturation in the rat adult hippocampus in vivo. BrdU effects across a wide range of doses (40-480 mg/kg) on cell proliferation and the population of immature neurons in the adult hippocampus were investigated using immunohistochemical labeling methods for the cell cycle marker Ki67 and a marker for immature neurons, doublecortin. BrdU did not influence cell proliferation in the dentate gyrus or the population of immature neurons observed in the adult hippocampus relative to those observed in saline treated controls. Thus, in contrast with reports of deleterious effects of BrdU in embryonic and neonatal tissue and adult tissue studied in vitro, BrdU does not appear to have cytotoxic effects on proliferating hippocampal cells or immature neurons in vivo in rats.

Role of apoptotic regulators in human epithelial ovarian cancer

We assessed molecular markers such as BRCA1, K-ras, p53, Bcl-2, Bcl-XL, Survivin and telomerase activity in untreated ovarian cancer tissue samples, ascitic cells and normal ovarian tissues and gathered insights into their correlation with each other and also with apoptotic index. The expression of these proteins was analyzed by Western blotting and immunohistochemistry. Apoptotic index was determined by TUNEL assay and telomerase activity was measured by PCR-ELISA kit. p53, Bcl-2, Bcl-XL, K-ras and Survivin were found to be over expressed in tumors and ascitic cells as compared to normal controls whereas there was no significant difference in expression of BRCA1. A significantly higher telomerase activity and lower apoptotic index in tumors as compared to controls was observed. p53 positively correlated with Bcl-2, Bcl-XL, K-ras and Survivin expression and also clinical stage of the disease. A positive correlation between Survivin and Bcl-2, Bcl-XL was seen. Apoptotic Index, telomerase activity and BRCA1 expression showed no correlation with any of the parameters. Our study confirms the fact that multiple gene interactions govern the pathogenesis of ovarian cancer, and analyzing ascitic cells of ovarian cancer patients may help to delineate molecular profile of the primary tumor.

Hypoxic-ischemic changes in SIDS brains as demonstrated by a reduction in MAP2-reactive neurons

Sudden infant death syndrome (SIDS) is characterized by a lack of any known morphological or functional organ changes that could explain the lethal process. In the present study we investigated the hypothesis of an association between hypoxic/ischemic injury and SIDS deaths. In a previous study, we could demonstrate by quantitative immunohistochemistry a distinct drop in microtubule-associated protein (MAP2) reactivity in neurons of adult, human brains secondary to acute hypoxic-ischemic injuries. Here we applied the same method on sections of the frontal cortex and hippocampus of 41 brains of infants younger than 1 year of age. For each brain area 100 selected neurons were evaluated for their MAP2 reactivity in the different layers of the frontal cortex and in the different segments of the hippocampus. Three groups were compared: (1) SIDS victims (n = 17), (2) infants with hypoxia/ischemia (control group one; n = 14), (3) infants without hypoxic/ischemic injury (control group two; n = 10). The SIDS group and hypoxic/ischemic group exhibited a general reduction in the number of MAP2 reactive neurons in comparison with the non-hypoxic/ischemic injury group. The SIDS group also had a significantly lower (P < 0.05) number of reactive neurons in the CA2 and CA3 areas of the hippocampus than did control group two. No difference was detected between the SIDS group and control group one. The SIDS brains were thus found to display hypoxic/ischemic features without however providing evidence as to the cause of the oxygen reduction.

Prognostic value of survivin in locally advanced prostate cancer: study based on RTOG 8610

PURPOSE

To examine the prognostic value of nuclear and cytoplasmic survivin expression in men with locally advanced prostate cancer who were enrolled in Radiation Therapy Oncology Group (RTOG) protocol 8610.

METHODS AND MATERIALS

RTOG 8610 was a Phase III randomized study comparing the effect of radiotherapy plus short-term androgen deprivation with radiotherapy alone. Of the 456 eligible patients, 68 patients had suitably stained tumor material for nuclear survivin analysis and 65 patients for cytoplasmic survivin.

RESULTS

Compared with patients with nuclear survivin intensity scores of <or=191.2, those with intensity scores >191.2 had significantly improved prostate cancer survival (hazard ratio [HR], 0.45; 95% confidence interval [CI], 0.20-1.00, p = 0.0452). On multivariate analysis, nuclear survivin intensity scores >191.2 were significantly associated with improved overall survival (HR, 0.46; 95% CI, 0.25-0.86; p = 0.0156) and prostate cancer survival (HR, 0.36; 95% CI, 0.16-0.84; p = 0.0173). On univariate analysis, compared with patients with cytoplasmic survivin integrated optical density <or=82.7, those with an integrated optical density >82.7 showed a significantly increased risk of local progression (HR, 2.49; 95% CI, 1.03-6.01; p = 0.0421).

CONCLUSION

Nuclear overexpression of survivin was associated with improved overall and prostate cancer survival on multivariate analysis, and cytoplasmic overexpression of survivin was associated with increased rate of local progression on univariate analysis in patients with locally advanced prostate cancer treated on RTOG 8610. Our results might reflect the different functions of survivin and its splice variants, which are known to exist in distinct subcellular compartments.

Delayed melatonin administration promotes neuronal survival, neurogenesis and motor recovery, and attenuates hyperactivity and anxiety after mild focal cerebral ischemia in mice

Melatonin is a potent antioxidant with neuroprotective activity in animal models of ischemic stroke, which based on its lack of serious toxicity has raised hopes that it might be used for human stroke treatment in the future. This study investigated how subacute delivery of melatonin, starting at 24 hr after stroke onset, and continuing for 29 days (4 mg/kg/day; via drinking water), influences neuronal survival, endogenous neurogenesis, motor recovery and locomotor activity in C57Bl6/j mice submitted to 30-min middle cerebral artery occlusion. Histologic studies showed that melatonin improved neuronal survival and enhanced neurogenesis, even when applied 1 day after stroke. Cell survival was associated with a long-lasting improvement of motor and coordination deficits, evaluated by the grip strength and RotaRod tests, as well as with attenuation of hyperactivity and anxiety of the animals as revealed in open field tests. The robust functional neurologic improvements encourage proof-of-concept studies with melatonin in human stroke patients.

Survivin and cyclin D1 are jointly expressed in thyroid papillary carcinoma and microcarcinoma

In order to define more effective predictive markers for clinical management and prognosis, we evaluated the expression of cyclin D1 and survivin in large papillary thyroid carcinoma (LPTC) and microcarcinoma (PTM). Sixty-seven patients operated for papillary carcinoma (36 of which with PTM) were considered. Immunochemistry for cyclin D1 and survivin was performed in samples from tumor mass and nodal metastases. There were not significant differences between LPTC and PTM as to patients personal data, TNM or MACIS staging, nodal invasion and multifocality, while capsular invasion was significantly more frequent in LPTC. Cyclin D1 and survivin were expressed at a very high rate and almost to the same extent in LPTC and PTM, both in tumoral mass and in nodal metastases. Survivin showed only cytoplasmic expression. Cyclin D1 and survivin over-expression are probably early events in tumorigenesis of thyroid papillary carcinoma but their full role in the process of tumor progression and their clinical value are still to be investigated.

Survivin expressions in human hepatoma HepG2 cells exposed to ionizing radiation of different LET

Survivin is a member of the inhibitors of apoptosis (IAP) protein family that interferes with post-mitochondrial events including activation of caspases. To examine the regulation of survivin expression in response to irradiation with different linear energy transfer (LET), human hepatoma HepG2 cells were irradiated in vitro with X-rays and carbon ions. Cellular sensitivities to low- and high-LET radiation were determined by colony formation. Survivin expression at mRNA and protein level were measured with RT-PCR and Western blot analyses, respectively. Radiation-induced cell cycle arrest and apoptosis were investigated with flow cytometry. We found that low-LET X-rays induced dose-dependent increases in survivin expression. After exposure to high-LET carbon ions, survivin expression gradually increased from 0 to 4 Gy, and then declined at 6 Gy. More pronounced survivin expression, stronger G(2)/M phase arrest was observed after exposure to carbon ions in comparison with X-rays at doses from 0 to 4 Gy. These observations indicate that there is a differential survivin expression in response to different LET radiations and the cycle arrest mechanism may be associated with it. In addition, our data on induction of apoptosis are compatible with the assumption that survivin expression induced by low-LET X-rays radiation may play a critical role in inhibiting apoptosis. However, after irradiation with ions, an anti-apoptotic function of survivin is not evident, possibly because of the serious damage produced by densely ionizing radiation.

[Expression and clinical significance of microtubule-associated protein 1 light chain 3 (LC3) and Beclin1 in epithelial ovarian cancer]

BACKGROUND & OBJECTIVE

Some studies have showed that changes of autophagic capacity may be correlated to tumorigenesis and tumor development. This study was to investigate the expression of microtubule-associated protein 1 light chain 3 (LC3) and autophagy-related gene Beclin1 in ovarian tumor tissues, and explore their correlations to the tumorigenesis and development of epithelial ovarian carcinoma.

METHODS

Expressions of LC3 and Beclin1 in 25 specimens of benign ovarian tumor, 25 specimens of borderline ovarian tumor, and 75 specimens of epithelial ovarian carcinoma were detected by immunohistochemistry. The correlations of LC3 and Beclin1 expression to the clinicopathologic characteristics of the 75 epithelial ovarian cancer patients were analyzed.

RESULTS

The positive rates of LC3 and Beclin1 were significantly higher in benign and borderline ovarian tumors than in epithelial ovarian carcinoma (100% and 96% vs. 57%, P<0.001; 100% and 84% vs. 57%, P<0.001). The expression of LC3 was associated with FIGO stage and histological grade (P=0.017;0.001). The expression of Beclin1 was related to FIGO stage (P=0.04). The expression of LC3 was not correlated to Beclin1 (P=0.875).

CONCLUSIONS

Expressions of LC3 and Beclin1 are down-regulated in epithelial ovarian cancer tissues. The decrease of autophagic capacity may relate to tumorigenesis and the development of epithelial ovarian cancer.

A molecular pathway involved in the generation of microtubule-associated protein 2-positive cells from microglia

We have recently demonstrated that microglia as multipotential stem cells give rise to microtubule-associated protein 2 (MAP2)-positive and glial fibrillary acidic protein (GFAP)-positive cells and that microglia-derived MAP2-positive cells possess properties of functional neurons. In this study, we investigated the molecular pathways involved in the generation of microglia-derived MAP2-positive and GFAP-positive cells. Western blot analyses demonstrated that expression levels of Id2 protein, an inhibitory basic helix-loop-helix transcription factor of the inhibitor of differentiation and DNA binding family, and Smad proteins were upregulated under differentiation conditions. Immunocytochemical analyses demonstrated that the generation of MAP2-positive and GFAP-positive cells from microglia was promoted by bone morphogenetic proteins (BMPs) and was inhibited by noggin which is a BMP antagonist, Smad4 siRNA and Id2 siRNA. These results indicate that activation of BMP signaling through Smad and Id2 proteins is one of the molecular pathways involved in the generation of microglia-derived MAP2-positive and GFAP-positive cells.

Autophagy is increased after traumatic brain injury in mice and is partially inhibited by the antioxidant gamma-glutamylcysteinyl ethyl ester

Autophagy is a homeostatic process for recycling of proteins and organelles, induced by nutrient deprivation and regulated by oxygen radicals. Whether autophagy is induced after traumatic brain injury (TBI) is not established. We show that TBI in mice results in increased ultrastructural and biochemical evidence of autophagy. Specifically, autophagosomal vacuoles and secondary lysosomes were frequently observed in cell processes and axons in ipsilateral brain regions by electron microscopy, and lipidated microtubule-associated protein light chain 3, a biochemical footprint of autophagy referred to as LC3 II, was increased at 2 and 24 h after TBI versus controls. Since oxygen radicals are believed to be important in the pathogenesis of TBI and are essential for the process of starvation-induced autophagy in vitro, we also sought to determine if treatment with the antioxidant gamma-glutamylcysteinyl ethyl ester (GCEE) reduced autophagy and influenced neurologic outcome after TBI in mice. Treatment with GCEE reduced oxidative stress and partially reduced LC3 II formation in injured brain at 24 h after TBI versus vehicle. Treatment with GCEE also led to partial improvement in behavioral and histologic outcome versus vehicle. Taken together, these data show that autophagy occurs after experimental TBI, and that oxidative stress contributes to overall neuropathology, in part by initiating or influencing autophagy.

Quantitative analysis of survivin mRNA expression in bladder transitional cell carcinomas

We assessed the expression levels of survivin mRNA in bladder transitional cell carcinoma (TCC) to provide additional information regarding its malignant potential. The real-time PCR method was used to detect the survivin mRNA level for 21 bladder tumor specimens, and for urinary exfoliated cells from 12 newly diagnosed bladder tumor patients. All bladder tumor specimens and 7 of 12 voided urine specimens expressed survivin mRNA. In tumor specimens, high grade, high stage tumors had the tendency to express more survivin mRNA. Of 12 superficial bladder tumor patients who had transurethral resection of bladder tumor (TURB), 3 showed high survivin mRNA expression and intravesical recurrence after the surgery. However, for the patients who had total cystectomy due to invasive tumor, no relations were observed between the survivin mRNA expression level and development of local recurrence and/or distant metastasis. Our results suggested that the quantitative analysis of the survivin mRNA may indicate local malignant potential, which contribute to the possibility of an intravesical recurrence.

A new subtype-specific monoclonal antibody for IAP-survivin identifies high-risk patients with diffuse large B-cell lymphoma and improves the prognostic value of bcl-2

Anti-apoptotic factors including IAP-survivin and bcl-2 are involved in carcinogenesis and predict for disease outcome for patients with cancer. We used RT-PCR and specific primers to generate two recombinant IAP-survivin proteins; one encoding for the full-length protein and the second comprising the survivin sequence incorporating amino acids 98 to 142. Both proteins were used to immunize mice and as capture antigens to screen NS1/immune splenocyte hybridoma supernatants for anti-survivin antibody in ELISA assays. The antibody designated F2-9C3 was most effective and reacted with both recombinant proteins and with the native protein present in lysates of A549 (lung carcinoma) and Jurkat cells in Western blots, immunoprecipitation and formalin-fixed tissue sections. Immunohistochemical staining of normal and neoplastic tissues showed association of the F2-9C3 antibody with the mitotic spindles. Expression of survivin was not detected elsewhere in sections of normal tissue while all neoplastic tissues examined, including those from patients with diffuse large B-cell lymphoma (DLBCL), showed significant expression of survivin. The intensity and localization of staining in these tumours varied and was observed in cytoplasm and/or nuclei. High nuclear expression of survivin predicted the disease outcome in patients with DLBCL. This association was evident when relating intensity to patient survival (p=0.0321) and strengthened when a score was calculated based on both staining intensity and the proportion of the reactive tumour cells (p=0.0128; reduction in the mean survival times: 35% and 46%, respectively). Elevated expression of bcl-2 protein also identified the high-risk patients (p=0.0095; reduction in mean survival time: 37%). Over-expression of both factors was a more powerful indicator of poor prognosis than either marker alone (p=0.0054, 70% reduction in mean survival time). In conclusion, our novel F2-9C3 monoclonal antibody is effective in determination of expression of IAP-survivin in neoplastic tissue. Nuclear overexpression of IAP-survivin using this antibody predicts the disease outcome in patients with DLBCL and significantly improves the predictive power of bcl-2 in these patients.

Survivin, p53, and Ki-67 as predictors of histopathologic response in locally advanced rectal cancer treated with preoperative chemoradiotherapy

PURPOSE

The ability to predict response to chemoradiotherapy before the treatment may allow protecting poorly responding patients from the side effects of neoadjuvant treatment. Several molecular markers have been proposed to radio and chemosensitivity of rectal cancer. In this study, from pre-irradiation tumor biopsies, a novel and promising candidate factor survivin, and p53 and Ki-67 were assessed as predictors of response to preoperative chemoradiotherapy.

MATERIALS AND METHODS

Expression of each marker was evaluated by immunohistochemistry on pretreatment biopsies from 37 patients having rectal cancer treated with preoperative chemoradiotherapy and curative surgery. Treatment response was assessed histopathologically in the resected surgical specimen.

RESULTS

There was no correlation between expression of p53, Ki-67, and survivin with response to preoperative chemoradiotherapy and prognosis.

CONCLUSIONS

Our data suggest that these molecular markers are not helpful to identify patients who would have benefit from neoadjuvant treatment of rectal cancer. Further investigations are necessary to select patients for preoperative treatment based on analysis of the preoperative biopsies.

Survivin gene expression in granulosa cells from infertile patients undergoing in vitro fertilization–embryo transfer

OBJECTIVE

To evaluate survivin gene expression in granulosa cells from infertile patients and examine the relationship between survivin gene expression and infertile clinical background.

DESIGN

Prospective study.

SETTING

IVF-ET program at Osaka Medical College.

PATIENT(S)

Twenty-eight patients underwent ovulation induction for IVF-ET performed because of tubal infertility, male factor infertility, or endometriosis.

INTERVENTION(S)

Granulosa cells obtained at oocyte retrieval were examined for survivin gene expression by quantitative reverse transcription-polymerase chain reaction.

MAIN OUTCOME MEASURE(S)

Hormone environment, number of oocytes, fertilization rate, high-quality embryo rate, pregnancy rate, and expression of survivin genes.

RESULT(S)

Survivin gene expression was detected in all granulosa cells. The gene expression levels of survivin in patients with endometriosis were significantly lower than those in patients with male factor infertility. The gene expression levels of survivin in total pregnant patients were higher than those in total nonpregnant patients and than those in the male factor infertility group, and there was no correlation between gene expression level and serum E(2) level.

CONCLUSION(S)

Survivin may be used as an indicator of the success of IVF-ET, and the existence of endometriosis may elevate the apoptosis of granulosa cells.

Histone deacetylase inhibitor trichostatin A induced caspase-independent apoptosis in human gastric cancer cell

BACKGROUND

Histone deacetylase inhibitors (HDACIs) have been reported to induce apoptosis in cancer cells. The effects of trichostatin A (TSA) on gastric cancer cells have not been well characterized. This study was aimed to explore the effects and mechanisms of TSA on human gastric cancer SGC-7901 cells.

METHODS

The cells were treated with TSA and analyzed by cell proliferation assay, Western blot, TUNEL assay, flow cytometry by fluorescein isothiocyanate (FITC) conjugated with Annexin V and PI staining, immunofluorescence analysis, analysis of subcellular fractionation, gene chips and real time polymerase chain reaction (PCR).

RESULTS

TSA could inhibit cell growth and induced apoptosis in gastric cancer SGC-7901 cells through the regulation of apoptosis-related genes, such as Bcl-2, Bax and survivin. Further study indicated that the pan-caspase inhibitor z-VAD-fmk did not inhibit the apoptosis induced by TSA, and we did not observe the cleavage of poly ADP ribose polymerase (PARP) after TSA treatment too. In addition, apoptosis inducing factor (AIF) and EndoG were found to translocate from mitochondria to nucleus in the immunofluorescence assay and the Western analysis of subcellular fractionation confirmed the result of immunofluorescence assay.

CONCLUSIONS

The apoptosis induced by TSA in gastric cancer SGC-7901 cells involves a caspase-independent pathway.

Three-dimensional cell organization leads to a different type of ionizing radiation-induced cell death: MG-63 monolayer cells undergo mitotic catastrophe while spheroids die of apoptosis

The type of cell death occurring in the same cell line (MG-63 human osteosarcoma cells) grown in monolayer or as three-dimensional spheroids after exposure to 5 Gy of ionizing radiation was determined. Morphological analyses using the chromatin dye Hoechst 33258 demonstrated that spheroids showed the typical characteristics of apoptosis, while monolayer cells revealed those typical of mitotic catastrophe. In order to better characterize these two types of cell death, the role of caspases was examined in irradiated monolayer cells and spheroids using the broad spectrum caspase inhibitor zVAD-fmk. Death in monolayer cells was caspase-independent, whereas spheroid death was characterized by caspase dependence. Members of the Bcl-2 family of proteins and survivin involved in cell death processes were also studied by Western blot analysis. The pro-apoptotic protein Bax increased in spheroids, whereas this protein remained unchanged in monolayer cells after the same 5-Gy irradiation. The anti-apoptotic protein Bcl-2, on the other hand, remained unchanged in both monolayer cells and spheroids. Finally, survivin increased significantly after irradiation in both cells in monolayer and spheroids. The results presented suggest that three-dimensional cell organization leads to a different type of cell death after exposure to ionizing radiation. Thus, the use of spheroids, a cell model which mimics in vivo solid tumors more closely than cells grown in monolayer, is more appropriate when investigating the effects of antineoplastic treatments such as ionizing radiation.

Bladder cancer biomarkers: current developments and future implementation

PURPOSE OF REVIEW

Bladder cancer biomarker development has advanced significantly over the last decade, but has not yet been able to make a significant impact in the diagnosis and management of the disease. Many available markers are suitable, but do not meet the expectations of physicians and patients. Patients do not want to compromise accuracy in diagnosing bladder cancer for less-invasive tests. The review highlights the latest developments in bladder cancer biomarkers, including markers developed over the last year, and comments on the high standards placed on these markers which have delayed their widespread implementation into the urologic field.

RECENT FINDINGS

New markers described in the last year include soluble Fas, urothelial carcinoma-associated 1 and human chorionic gonadotropin beta type II genes. The latter two markers represent the contribution of genomic technology to this field. Also described are updates to known markers, including long-term follow-up of hematuria screening, recent studies in DNA methylation for bladder cancer diagnosis and patient perspectives on bladder tumor markers.

SUMMARY

Biomarkers for bladder cancer have been intensively scrutinized over the last decade, but despite new findings and good performance characteristics, they are currently not accepted in clinical practice.

Attenuation of microtubule associated protein-2 degradation after mild head injury by mexiletine and calpain-2 inhibitor

The objective of the study was to address the early effects of mild, closed, head injuries on neuronal stability and the prevention of microtubule-associated protein-2 (MAP-2) degradation by mexiletine and calpain-2 inhibitor. Twenty-four rats were divided into four groups: control group (1); trauma group without treatment (2); mexiletine-pretreated and subjected to trauma group (3); trauma subjected and then calpain-2 inhibitor received group (4). All animals were subjected to mild, closed, head trauma. Frontal lobes were removed and processed for staining and immunofluorescent labelling of MAP-2 cytoskeletal proteins, which were evaluated by confocal microscopy in serial optical sections showing the three dimensional cytoarchitecture of affected areas. MAP-2 decoration in almost all neurons obtained from traumatized brain regions drastically diminished, while minute filamentous and granular profiles in axons and/or dendrites were retained together implying a massive degradation/depolymerization of microtubules. In contrast, in mexiletine-pretreated animals, MAP-2 positivity in axonal and perikaryonal profiles was fairly retained, which clearly depicts the protective role of mexiletine after trauma. Compared with mexiletine-pretreated group, calpain-2 inhibitor treated group displayed a less well-preserved MAP-2 expression. Mexiletine can prevent cytoskeletal structure and protein degradation after mild head trauma. Calpain-2 inhibitor prevents protein degradation, but cytoskeletal organization is better preserved with mexiletine.

Swimming against the tide: mobility of the microtubule-associated protein tau in neurons

Long-haul transport along microtubules is crucial for neuronal polarity, and transport defects cause neurodegeneration. Tau protein stabilizes microtubule tracks, but in Alzheimer's disease it aggregates and becomes missorted into the somatodendritic compartment. Tau can inhibit axonal transport by obstructing motors on microtubules, yet tau itself can still move into axons. We therefore investigated tau movement by live-cell fluorescence microscopy, FRAP (fluorescence recovery after photobleaching), and FSM (fluorescence speckle microscopy). Tau is highly dynamic, with diffusion coefficients of approximately 3 microm2/s and microtubule dwell times of approximately 4 s. This facilitates the entry of tau into axons over distances of millimeters and periods of days. For longer distances and times, two mechanisms of tau transport are observed. At low near-physiological levels, tau is cotransported with microtubule fragments from cell bodies into axons, moving at instantaneous velocities approximately 1 microm/s. At high concentrations, tau forms local accumulations moving bidirectionally at approximately 0.3 microm/s. These clusters first appear at distal endings of axons and may indicate an early stage of neurite degeneration.

Cell death in leukemia: passenger protein regulation by topoisomerase inhibitors

Etoposide is a potent inducer of mitotic catastrophe; a type of cell death resulting from aberrant mitosis. It is important in p53 negative cells where p53 dependent apoptosis and events at the G1 and G2 cell cycle checkpoints are compromised. Passenger proteins regulate many aspects of mitosis and siRNA interference or direct inhibition of Aurora B kinase results in mitotic catastrophe. However, there is little available data of clinical relevance in leukaemia models. Here, in p53 negative K562 myeloid leukemia cells, etoposide-induced mitotic catastrophe is shown to be time and/or concentration dependent. Survivin and Aurora remained bound to chromosomes. Survivin and Aurora were also associated with Cdk1 and were shown to form complexes, which in pull down experiments, included INCENP. There was no evidence of Aurora B kinase suppression. These data suggests etoposide will complement Aurora B kinase inhibitors currently in clinical trials for cancer.

Analysis of molecular pathological factors of unfavorable prognosis for young cervical cancer patients

The aim of this study was to explore the molecular pathological characteristics of cervical cancer in women aged below 35, disclose the factors that indicate the unfavorable prognosis, and provide some useful targets for improving therapeutic outcome.

PATIENTS AND METHODS

64 cases of pathological data originating from cervical cancer patients aged below 35 served as the study group to perform a retrospective research, and pathological data from 90 cases of cervical cancer patients beyond age 35, who underwent treatment during the same time, were selected at random as the reference group. Immunohistochemistry and quantified image analysis were utilized to detect synchronously the protein expression difference of survivin and p27 between the 2 groups.

RESULTS

The total 5-year survival rate of the study group was 65.6% compared to 84.4% in the reference group, while the lymph node metastasis rate was 25% compared to 12.2% in the reference group. Both differences were statistically significant (p < 0.05). Survivin expression is much greater in the study group than in the reference group (p < 0.05); there is no statistical difference of the p27 expression between the 2 groups (p > 0.05), but p27 expression is related to lymph node metastasis.

CONCLUSION

Younger female patients have a worse prognosis than older ones, and survivin expression is associated with poor prognosis. Targeting these molecular factors may lead to a hopeful biomedical therapy to improve the prognosis of young female cervical cancer patients.

Modification of cellular autophagy protein LC3 by poliovirus

Poliovirus infection remodels intracellular membranes, creating a large number of membranous vesicles on which viral RNA replication occurs. Poliovirus-induced vesicles display hallmarks of cellular autophagosomes, including delimiting double membranes surrounding the cytosolic lumen, acquisition of the endosomal marker LAMP-1, and recruitment of the 18-kDa host protein LC3. Autophagy results in the covalent lipidation of LC3, conferring the property of membrane association to this previously microtubule-associated protein and providing a biochemical marker for the induction of autophagy. Here, we report that a similar modification of LC3 occurs both during poliovirus infection and following expression of a single viral protein, a stable precursor termed 2BC. Therefore, one of the early steps in cellular autophagy, LC3 modification, can be genetically separated from the induction of double-membraned vesicles that contain the modified LC3, which requires both viral proteins 2BC and 3A. The existence of viral inducers that promote a distinct aspect of the formation of autophagosome-like membranes both facilitates the dissection of this cellular process and supports the hypothesis that this branch of the innate immune response is directly subverted by poliovirus.