Psoralen synergizes with exosome-loaded SPC25 to alleviate senescence of nucleus pulposus cells in intervertebral disc degeneration

OBJECTIVE

To explore the mechanism of psoralen synergized with exosomes (exos)-loaded SPC25 on nucleus pulposus (NP) cell senescence in intervertebral disc degeneration (IVDD).

METHODS

IVDD cellular models were established on NP cells by tert-butyl hydroperoxide (TBHP) induction, followed by the treatment of psoralen or/and exos from adipose-derived stem cells (ADSCs) transfected with SPC25 overexpression vector (ADSCs-oe-SPC25-Exos). The viability, cell cycle, apoptosis, and senescence of NP cells were examined, accompanied by the expression measurement of aggrecan, COL2A1, Bcl-2, Bax, CDK2, p16, and p21.

RESULTS

After TBHP-induced NP cells were treated with psoralen or ADSCs-oe-SPC25-Exos, cell proliferation and the expression of aggrecan, COL2A1, Bcl-2, and CDK2 were promoted; however, the expression of Bax, p16, p21, and inflammatory factors was decreased, and cell senescence, cycle arrest, and apoptosis were inhibited. Of note, psoralen combined with ADSCs-oe-SPC25-Exos further decelerated NP cell senescence and cycle arrest compared to psoralen or ADSCs-oe-SPC25-Exos alone.

CONCLUSION

Combined treatment of psoralen and ADSCs-oe-SPC25-Exos exerted an alleviating effect on NP cell senescence, which may provide an insightful idea for IVDD treatment.

Transcription Factor E2F8 Promotes Cisplatin Resistance in Hepatocellular Carcinoma by Regulating DNA Damage via NUSAP1

DNA damage repair has been the key mechanism of cisplatin resistance in hepatocellular carcinoma (HCC). The present study elucidated the molecular mechanism by which nucleolar and spindle-associated protein 1 (NUSAP1) influenced cisplatin tolerance in HCC by regulating DNA damage. First, high mRNA expression of E2F8 and NUSAP1 in HCC was detected by real-time quantitative PCR in cells and tumor tissue. The interaction between E2F8 and NUSAP1 was confirmed by chromatin immunoprecipitation (ChIP) and dual-luciferase reporter assays that E2F8 bound to the promoter region of NUSAP1 and regulated its transcriptional activity. The effects of the E2F8/NUSAP1 axis on cell viability, cell cycle, DNA damage protein γ-H2AX, and cisplatin resistance were investigated by CCK-8, flow cytometry, comet detection, and western blot. The results showed that NUSAP1 knockdown blocked the cell cycle in G0/G1 phase, promoted cisplatin-induced DNA damage, and enhanced cisplatin sensitivity in HCC. Overexpressed E2F8 promoted cell cycle arrest by silencing NUSAP1 in HCC, and promoting DNA damage as well as cisplatin sensitivity. In conclusion, our results suggested that E2F8 enhanced the chemoresistance of HCC cells to cisplatin by activating NUSAP1 to inhibit DNA damage, which provides a basis for describing new therapeutic targets that effectively exacerbate DNA damage and improve the chemical sensitivity of HCC to cisplatin.

Ischemia reperfusion myocardium injuries in type 2 diabetic rats: Effects of ketamine and insulin on LC3-II and mTOR expression

Objectives: Myocardiopathy occurs in ischemia-induced injury caused by dysregulation of autophagy of cardiac tissues. The present report evaluates the protective effect of ketamine and insulin against myocardial injury in type 2 diabetic rats (T2DM).Methods: The effects of ketamine and its combination with insulin on biochemical parameters and inflammatory cytokines in the serum of I/R-induced myocardial injury in T2DM rats were evaluated. The parameters of reactive oxygen species and the expression of autophagosome signaling pathway proteins were also determined. Using transmission electron microscopy, we investigated autophagosomes. Western blots were used to detect autophagy-associated signaling pathways. Myocardial function was determined by echocardiography and histopathological changes in myocardial tissues were also determined in I/R-induced myocardial injury in type 2 diabetic rats.Results: There was a significant reduction in glucose, AST, LDH, and CK-MB levels and cytokines (IL-1β, IL-6, and TNF-α) in serum of the ketamine (p < .05) and ketamine + insulin (p < .01) groups than in the diabetic + I/R. MDA and ROS levels were reduced with a substantial (p < .05) increase in GSH levels through improved cardiac function in the ketamine (p < .05) and ketamine + insulin (p < .01) groups than the diabetic + I/R group. There was an increase in mature autophagosomes in diabetic+I/R+Kt+In compared to diabetic+I/R+Kt alone in infarction and marginal zones. It should be noted that the significant increase (p < .01) in protein levels of the autophagy-associated intracellular signaling pathways AMPK and mTOR, as well as an increase in LC3-II and BECLIN-1, suggests that ketamine combined with insulin-activated autophagy-associated intracellular signaling AMPK and mTOR.Conclusion: The findings of the study suggest that ketamine combined with insulin administration remarkably protects I/R-induced myocardial injury in rats with T2DM by reducing the dysregulation of autophagy.

[Effect of heat-reinforcing needling on expression of serum inflammatory factors and autophagy of knee joint synovial tissue in rheumatoid arthritis rabbits with cold syndrome]

OBJECTIVE

To observe the effect of heat-reinforcing needling on the expression of serum inflammatory factors and autophagy of knee synovial tissue in rheumatoid arthritis (RA) rabbits with cold syndrome, so as to explore its mechanism of anti-inflammatory in the treatment of RA.

METHODS

Fifty rabbits were randomly divided into normal, model, heat-reinforcing needling, inhibitor and agonist groups (n=10 rabbits in each group). The model of RA with cold syndrome was established by Freund's adjuvant and ovalbumin mixed solution injection combined with freezing and wind-cold dampness method. Heat-reinforcing needling was applied at "Zusanli" (ST36) for 30 min, once a day for 14 days. Rabbits of the inhibitor and agonist groups were given intraperitoneally injected with autophagy inhibitor 3-methyladenine (3-MA) or autophagy agonist rapamycin, once every 2 days for 7 days. The knee circumference and skin temperature of the rabbits in each group were measured. Color doppler ultrasonography was applied to examine the synovial membrane, joint effusion and blood flow signals in the knee joints of the rabbits in each group. Serum tumor necrosis factor (TNF) -α, interleukin (IL)-1β, IL-6 and C-creactive protein (CRP) were detected by ELISA. Transmission electron microscopy was applied to observe the ultrastructure and autophagosomes of synovial cells. The protein expressions of autophagy-related protein Atg5, serine/threonine protein kinase-dysregulated 51-like kinase 1 (ULK1), microtubule-associated protein light chain 3B (LC3B), and Beclin-1 were detected by Western blot. Fluorescence quantitative PCR was used to detect the mRNA expressions of NOD-like receptor 3 (NLRP3) and nuclear factor-κB (NF-κB).

RESULTS

Compared with the normal group, the circumference of the knee joint was increased (P<0.01), the skin temperature was decreased (P<0.01), the knee joint synovium was thickened and the blood flow signal was abundant, the contents of serum TNF-α, IL-1β, IL-6, and CRP were increased (P<0.01), the protein expressions of Atg5, ULK1, Beclin-1 and LC3BⅡ/LC3BⅠof synovial tissue were significantly decreased (P<0.01), the mRNA expressions of NLRP3 and NF-κB were increased (P<0.01) in the model group. In comparison with the model and inhibitor groups, the circumference of the knee joint was decreased (P<0.01), whlie the skin temperature was increased (P<0.01), the synovial membrane became thinner and the blood flow signal was wea-kened, the contents of TNF-α, IL-1β, IL-6 and CRP were decreased (P<0.01), the protein expressions of Atg5, ULK1, Beclin-1 and LC3B Ⅱ/LC3B Ⅰ were increased (P<0.01), and the mRNA expressions of NLRP3 and NF-κB were decreased (P<0.01) in the heat-reinforcing needling and agonist groups.

CONCLUSION

Heat-reinforcing needling can alleviate the inflammatory response of the knee joint synovium in RA rabbits with cold syndrome, which may be related to its function in enhancing the autophagy activity of synovial cells and inhibiting the synthesis and release of inflammatory factors TNF-α, IL-1β, IL-6 and CRP.

Therapeutic potential of pregnenolone and pregnenolone methyl ether on depressive and CDKL5 deficiency disorders: Focus on microtubule targeting

Pregnenolone methyl-ether (PME) is a synthetic derivative of the endogenous neuroactive steroid pregnenolone (PREG), which is an important modulator of several brain functions. In addition to being the precursor of steroids, PREG acts directly on various targets including microtubules (MTs), the functioning of which is fundamental for the development and homeostasis of nervous system. The coordination of MT dynamics is supported by a plethora of MT-associated proteins (MAPs) and by a specific MT code that is defined by the post-translational modifications of tubulin. Defects associated with MAPs or tubulin post-translational modifications are linked to different neurological pathologies including mood and neurodevelopmental disorders. In this review, we describe the beneficial effect of PME in major depressive disorders (MDDs) and in CDKL5 deficiency disorder (CDD), two pathologies that are joint by defective MT dynamics. Growing evidence indeed suggests that PME, as well as PREG, is able to positively affect the MT-binding of MAP2 and the plus-end tracking protein CLIP170 that are both found to be deregulated in the above mentioned pathologies. Furthermore, PME influences the state of MT acetylation, the deregulation of which is often associated with neurological abnormalities including MDDs. By contrast to PREG, PME is not metabolised into other downstream molecules with specific biological properties, an aspect that makes this compound more suitable for therapeutic strategies. Thus, through the analysis of MDDs and CDD, this work focuses attention on the possible use of PME for neuronal pathologies associated with MT defects.

[Endothelial monocyte-activating polypeptide-II: properties, functions, and pathogenetic significance]

Endothelial dysfunction is implicated in the pathogenesis of diabetes and atherosclerosis. Endothelial monocyte-activating polypeptide-II (EMAP-II) is a multifunctional polypeptide with proinflammatory and antiangiogenic activity. EMAP-II induces procoagulant activity on the surface of endothelial cells, increases expression of E- and P-selectins and tumor necrosis factor-1, directs migration of monocytes and neutrophils, induces apoptosis in endothelial cells. The mechanisms of effects on endothelial cells, inflammatory action, anti-tumor properties, pathogenic role in diseases of the central nervous system involved in the development of the lungs during embryogenesis and pathogenic role in diseases of the lungs, in the development of cardiovascular disease.

[Buzhong yiqi decoction containing serum reversed resistance of A549/DDP to cisplatin and its effect on the expression of survivin: an experimental research ]

OBJECTIVE

To analyze the reversal effect of Buzhong Yiqi Decoction (BYD) on multidrug resistance of human adenocarcinoma of lung cell line A549/DDP, and to study its effect on the expression of survivin by using serum pharmacological methods in vitro. Methods Totally 24 SD rats were divided into the high, medium and low dose groups, and the blank control group by randomized controlled method. The high dose BYD containing serum (1. 134 g/mL, 2 mL), the middle dose BYD containing serum (0.576 g/mL, 2 mL), and the low dose BYD containing serum (0.284 g/mL, 2 mL) were prepared. The inhibitory effects of different dose and concentrations BYD on the proliferation of A549 and A549/DDP cells were detected by MTT assay, and the drug resistance reversal fold was calculated. The expression of Survivin in the two cell strains were detected respectively by immunohistochemical assay, Western blot, and immunofluorescence method.

RESULTS

BYD containing serum showed obvious inhibitory effect on the growth of A549 and 549/DDP. The inhibition rates of 10% dose groups were higher than those of 5% dose groups. Besides, it gradually increased along with increased concentrations. Compared with 10% blank control group, the inhibition rate increased in 10% middle and low dose groups (P <0.05). After acted with 10% middle dose BYD containing serum, IC50, of A549 and A549/DDP were both reduced (P <0.05), reversal fold (RF) both increased. Its reversal ratio on A549/DDP cells was 2. 46, decreasing the resistance of A549/DDP to DDP. Compared with A549 in the same group, the expression of Survivin was detected to decrease by immunocytochemical assay, Western blot, and immunofluorescence method (P<0.05). Compared with 10% blank control group, the inhibition rate decreased in 10% middle dose group (P <0. 05).

CONCLUSIONS

10% middle dose BYD containing serum could significantly inhibit the apoptosis of A549 and A549/DDP. Besides, it could moderately reverse the multidrug resistance of A549/DDP cells to DDP possibly through reducing the intracellular expression of Survivin and enhancing the sensitivity 549/DDP to chemotherapeutics.

The use of functional chemical-protein associations to identify multi-pathway renoprotectants

Typically, most nephropathies can be categorized as complex human diseases in which the cumulative effect of multiple minor genes, combined with environmental and lifestyle factors, determines the disease phenotype. Thus, multi-target drugs would be more likely to facilitate comprehensive renoprotection than single-target agents. In this study, functional chemical-protein association analysis was performed to retrieve multi-target drugs of high pathway wideness from the STITCH 3.1 database. Pathway wideness of a drug evaluated the efficiency of regulation of Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways in quantity. We identified nine experimentally validated renoprotectants that exerted remarkable impact on KEGG pathways by targeting a limited number of proteins. We selected curcumin as an illustrative compound to display the advantage of multi-pathway drugs on renoprotection. We compared curcumin with hemin, an agonist of heme oxygenase-1 (HO-1), which significantly affects only one KEGG pathway, porphyrin and chlorophyll metabolism (adjusted p = 1.5×10⁻⁵). At the same concentration (10 µM), both curcumin and hemin equivalently mitigated oxidative stress in H₂O₂-treated glomerular mesangial cells. The benefit of using hemin was derived from its agonistic effect on HO-1, providing relief from oxidative stress. Selective inhibition of HO-1 completely blocked the action of hemin but not that of curcumin, suggesting simultaneous multi-pathway intervention by curcumin. Curcumin also increased cellular autophagy levels, enhancing its protective effect; however, hemin had no effects. Based on the fact that the dysregulation of multiple pathways is implicated in the etiology of complex diseases, we proposed a feasible method for identifying multi-pathway drugs from compounds with validated targets. Our efforts will help identify multi-pathway agents capable of providing comprehensive protection against renal injuries.

Ethanol impairs microtubule formation via interactions at a microtubule associated protein-sensitive site

Prolonged ethanol abuse has been associated with brain injury caused by impaired synaptogenesis, cellular migration, neurogenesis, and cell signaling, all of which require proper microtubule functioning. However, the means by which ethanol may impair microtubule formation or function and the role that microtubule-associated proteins (MAPs) have in mediating such effects are not clear. In the present studies, purified MAP-deficient (2 mg/mL) and MAP-rich (pre-conjugated; 1 mg/mL) bovine α/β tubulin dimer was allowed to polymerize at 37 °C, forming microtubules in the presence or absence of ethanol (25-500 mM). Microtubule formation was assessed in a 96-well format using a turbidity assay, with absorption measured at 340 nm for 45 min. Additional studies co-exposed α/β tubulin dimers to 50 mM ethanol and purified MAPs (0.1 mg/mL) for 45 min. Polymerization of MAP-deficient tubulin was significantly decreased (at 15-45 min of polymerization) during exposure to ethanol (>25 mM). In contrast, ethanol exposure did not alter polymerization of α/β tubulin dimers pre-conjugated to MAPs, at any concentration. Concurrent exposure of MAP-deficient tubulin with purified MAPs and ethanol resulted in significant and time-dependent decreases in tubulin polymerization, with recovery from inhibition at later time points. The present results suggest that ethanol disrupts MAP-independent microtubule formation and MAP-dependent microtubule formation via direct actions at an MAP-sensitive microtubule residue, indicating that disruption of neuronal microtubule formation and function may contribute to the neurodegenerative effects of binge-like ethanol intake.

Overexpression of Arabidopsis translationally controlled tumor protein gene AtTCTP enhances drought tolerance with rapid ABA-induced stomatal closure

Translationally controlled tumor protein (TCTP), also termed P23 in human, belongs to a family of calcium- and tubulin-binding proteins, and it is generally regarded as a growth-regulating protein. Recently, Arabidopsis TCTP (AtTCTP) has been reported to function as an important growth regulator in plants. On the other hand, plant TCTP has been suggested to be involved in abiotic stress signaling such as aluminum, salt, and water deficit by a number of microarray or proteomic analyses. In this study, the biological functions of AtTCTP were investigated by using transgenic Arabidopsis plants overexpressing AtTCTP. Interestingly, AtTCTP overexpression enhanced drought tolerance in plants. The expression analysis showed that AtTCTP was expressed in guard cells as well as in actively growing tissues. Physiological studies of the overexpression lines showed increased ABA- and calcium-induced stomatal closure ratios and faster stomatal closing responses to ABA. Furthermore, in vitro protein-protein interaction analysis confirmed the interaction between AtTCTP and microtubules, and microtubule cosedimentation assays revealed that the microtubule binding of AtTCTP increased after calcium treatment. These results demonstrate that the overexpression of AtTCTP confers drought tolerance to plants by rapid ABA-mediated stomatal closure via the interaction with microtubules in which calcium binding enhances the interaction. Collectively, the present results suggest that the plant TCTP has molecular properties similar to animal TCTPs, such as tubulin- and calcium-binding, and that it functions in ABA-mediated stomatal movement, in addition to regulating the growth of plants.

[Effect of survivin antisense oligodeoxynucleotide on proliferation and apoptosis of human malignant melanoma cells]

OBJECTIVE

To investigate the effect of survivin antisense oligodeoxynucleotide (ASODN) on proliferation and apoptosis of human malignant melanoma cells.

METHODS

hMMC A375 colonies in log growth phase were collected and divided into control group (C, without transfection), sense chain group [SC, transfected with 600 nmol/L survivin sense oligodeoxynucleotide (ODN)], mismatch chain group (MC, transfected with 600 nmol/L survivin mismatch sense ODN), liposome group (L, treated with liposome), antisense chain group (AC, transfected with survivin ASODN, and subdivided into AC 200, 400, 600 nmol/L subgroups) according to the random number table. Transfection result was observed under inverted fluorescence microscope. Inhibition rate of cell proliferation was calculated after determination of cell viability with MTT method. Cell cycle and apoptosis rate were detected with bi-variable flow cytometry. Expression of survivin protein was determined with Western blot. Activity of caspase-3 was assessed with kinase method. Data were processed with analysis of variance.

RESULTS

(1) Cell transfection rates in SC, MC, AC 600 nmol/L groups were all above 80%. (2) Compared with those in SC group [(5.23 +/- 0.25)%], MC group [(5.09 +/- 0.13)%] and L group [(4.70 +/- 0.45)%], inhibition rates of cell proliferation in AC 200, 400, 600 nmol/L groups 24 hours after transfection [(10.30 +/- 0.56)%, (16.69 +/- 0.58)%, (24.67 +/- 0.67)%] were significantly increased (F = 746.91, and P values all below 0.05). As time after transfection went on, proliferation inhibition rate was increased obviously. (3) Apoptosis rate in AC 200, 400, 600 nmol/L groups 24 hours after transfection was respectively (13.5 +/- 1.9)%, (20.1 +/- 1.5)%, (32.1 +/- 2.9)%, which were significantly higher than those in C, SC, MC, and L groups [(6.5 +/- 0.6)%, (5.6 +/- 0.7)%, (6.4 +/- 1.0)%, (6.5 +/- 1.3)%, F = 139.9, P values all below 0.05]. Cells in AC group were blocked in G2/M stage. (4) Compared with those in C group, expression amount of survivin protein decreased, and caspase-3 activity obviously increased (F = 63.1, P values all below 0.05) in AC group. No significant difference in caspase-3 activity between SC, MC, L groups and C group was observed (F = 0.512, P values all above 0.05).

CONCLUSIONS

Survivin ASODN can inhibit the proliferation of hMMC A375 in a concentration-time dependent manner, and it induces G2/M stage block and promotes its apoptosis.

[Transcription of cytoskeleton protein genes in differentiation of neurons from mouse embryonic stem cells induced by small molecules]

OBJECTIVE

To investigate the transcription of cytoskeleton protein genes in differentiation of neurons from mouse embryonic stem (ES) cells induced by all-trans retinoic acid (RA), and to explore the possibility of setting up a method to screen small molecules with promoting or inhibiting effect.

METHODS

The hanging drop method was employed for embryonic body formation to mimic embryo development in vivo. Reverse transcriptase PCR (RT-PCR) was performed to investigate mRNA expression of the neuron-specific cytoskeleton proteins including Mtap2, Nefm and beta-tubulin III which were regarded as the inducing effect indexes of RA. Morphological evaluation and immunocytochemistry staining were conducted to identify the neural derivatives. Moreover, the inducing effects of six synthetic molecules were further evaluated.

RESULT

RA up-regulated the mRNA expression of Mtap2 and Nefm, especially Mtap2 increased by 1.27 times, which was consistent with the morphological alteration. However, there was no significant changes of beta-tubulin III expression. With addition of the six synthetic molecules, the transcription of Mtap2 was inhibited, while the Nefm mRNA expression was up-regulated in some degree, especially for molecule 1 and 3 that was increased by 1.4 and 1.2 times, which, however, was not parallel to the morphological changes.

CONCLUSION

The transcriptional levels of Mtap2 and Nefm are both up-regulated in the RA-induced differentiation of ES cells towards neurons. The up-regulation of Mtap2 is consistent with the morphological alteration, which might be the key landmark in the RA-induced differentiation of ES cells into neurons.

[Effects of survivin antisense oligodeoxynucleotide on drug resistance in K562 cells]

OBJECTIVE

To study the effect of Survivin antisense oligodeoxgnucleotide (ASODN) on drug resistance and its mechanism in K562 cells.

METHODS

Cells were divided into four groups: ASODN group, SODN group, Lip group and blank group. Survivin ASODN was transfered into K562 cells by liposomal reagent. The expression of Survivin mRNA was detected by RT-PCR. The sensitivity of K562 cells to adriamycin (ADM) and daunorubicin (DAM) was detected by MTT assay, while the intracellular concentration of ADM and DAM was measured by flowcytometry.

RESULTS

Compared to control group Survivin mRNA expression in ASODN group decreased obviously. IC50(s) of ADM and ASODN+ADM were 0.5457 mg/L and 0.1933 mg/L respectively, IC50 (s) of DAM and ASODN+DAM were 0.5408 mg/L and 0.2027 mg/L respectively. Expression of Survivin mRNA decreased by 25.8% after the transfection of ASODN. Fluorescence intensity of ADM and ASODN+ADM in K562 cells were 51.64 and 89.92, Fluorescence intensity of DAM and ASODN+DAM in K562 cells were 63.71 and 88.47.

CONCLUSION

Expression of Survivin mRNA in k562 cells was down-regulated by ASODN. Survivin ASODN is able to reverse the drug resistance via inhibition of Survivin expression and inducement of apoptosis.

[Polyamidoamine dendrimer-mediated survivin antisense oligonucleotide inhibits the growth of subcutaneously transplanted colorectal cancer in nude mice]

OBJECTIVE

To evaluate the inhibitory effects of survivin antisense oligonucleotide (survivin-ASODN) mediated by polyamidoamine dendrimer (PAMAM) against the growth of subcutaneously transplanted colorectal cancer in nude mice.

METHODS

Nude mouse models bearing colorectal cancer was established by subcutaneous injection of SW620 cells. Survivin- OSADN (300 microg/L) was mixed with 4.06 microg/L PAMAM or liposome to prepare two transfection complexes, and their morphologies were observed by transmission electron microscope. The particle size of the prepared complexes was determined by laser particle size analyzer, and the zeta potential was measured. The encapsulation efficiency and the DNA release rate in vitro were determined by ultraviolet spectrophotometer. The transfection complexes were then directly injected into the xenografts of the tumor-bearing nude mice. The tumor volume changes were observed, and the expression of survivin in the transplanted tumor was measured by Western blotting.

RESULTS

The PAMAM-survivin-ASODN complex had a significantly smaller diameter and greater zeta potential than liposome-survivin-ASODN (P<0.01 and 0.05, respectively). The encapsulation efficiency was comparable between the two complexes. In in vitro condition, PAMAM-survivin-ASODN allowed sustained survivin-ASODN release for as long as 14 days, as compared with the 5 days for the liposome complex. After injection into the tumor xenografts, PAMAM-survivin- ASODN resulted in significantly lower expression of survivin protein in the transplanted tumors (P<0.05), and also in significantly greater reduction of the tumor volume than the liposome complex (P<0.05).

CONCLUSION

PAMAM can effectively deliver survivin-ASODN into transplanted colorectal tumor cells to reduce the expression of survivin and inhibit the tumor growth.

[CIAPIN1 expression in human lung cancer tissues and inhibitory effects of the gene on human pulmonary carcinoma NCI-H446 cells]

AIM

To explore CIAPIN1 gene expression in lung carcinoma tissues and its regulatory in the growth of NCI-H446.

METHODS

Fifty-one formalin-fixed paraffin-embedded specimens of primary lung cancer and their non-cancerous counterparts were detected by SABC immunohistochemistry method. Adenoviral vector construction was recombined and the gene was transduced into NCI-H446 cells. The expression of CIAPIN1 protein was identified by Western blot. Trypan blue staining was used to count the alive cells and to draw a cellular growth curve. The changes of cell cycle and apoptosis were analyzed by flow cytometry.

RESULTS

The positive rate of CIAPIN1 expression in cancer tissues (39.2%)was much lower than that in non-cancerous counterparts (100%, P<0.05). In Ad-CIAPIN1 group, the growth of transfected NCI-H446 cells in vitro was significantly inhibited. In addition the Ad-CIAPIN1-induced cell apoptosis and a predominant arrest in the G1/S phase (P<0.01) were observed.

CONCLUSION

The down-regulation of CIAPIN1 expression in tumor is associated with the development of lung carcinoma. Transduction of NCI-H446 CIAPIN1-negative cell, with Ad-CIAPIN1 can inhibit cell growth, suggesting that CIAPIN1 can be a new tumor-related suppressor gene.

Apoptosis: a relevant tool for anticancer therapy

Apoptosis is a form of cell death that permits the removal of damaged, senescent or unwanted cells in multicellular organisms, without damage to the cellular microenvironment. Defective apoptosis represents a major causative factor in the development and progression of cancer. The majority of chemotherapeutic agents, as well as radiation, utilize the apoptotic pathway to induce cancer cell death. Resistance to standard chemotherapeutic strategies also seems to be due to alterations in the apoptotic pathway of cancer cells. Recent knowledge on apoptosis has provided the basis for novel targeted therapies that exploit apoptosis to treat cancer. These new target include those acting in the extrinsic/intrinsic pathway, proteins that control the apoptosis machinery such as the p53 and proteosome pathway. Most of these forms of therapy are still in preclinical development because of their low specifity and susceptibility to drug resistance, but several of them have shown promising results. In particular, this review specifically aims at providing an update of certain molecular players that are already in use in order to target apoptosis (such as bortezomib) or which are still being clinically evaluated (such ONYX-015, survivin and exisulind/aptosyn) or which, following preclinical studies, might have the necessary requirements for becoming part of the anticancer drug programs (such as TRAIL/Apo2L, apoptin/VP3).

Binding of TPX2 to Aurora A alters substrate and inhibitor interactions

The Aurora kinases are a family of serine/threonine kinases involved in mitosis. The expression of AurA is ubiquitous and cell cycle regulated. It is overexpressed in many tumor types, including breast, colon, and ovarian. TPX2 is a binding partner and activator of AurA. A fragment of TPX2 (residues 1-43) has been shown to be sufficient for binding, kinase activation, and protection from dephosphorylation. We have shown that the addition of TPX2(1-43) increases the catalytic efficiency of AurA. While TPX2 binding has no effect on the turnover number of AurA and does not change the reaction mechanism (characterized here to be a rapid equilibrium random mechanism), it increases the binding affinity of both ATP and a peptide substrate. We have also demonstrated differences in the inhibitor structure-activity relationship (SAR) in the presence or absence of TPX2(1-43). To better understand the differential SAR, we carried out computer modeling studies to gain insight into the effect of TPX2 on the binding interactions between AurA and inhibitors. Our working hypothesis is that TPX2 binding decreases the size and accessibility of a hydrophobic pocket, adjacent to the ATP site, to inhibitors.

Cargo selection by specific kinesin light chain 1 isoforms

Kinesin-1 drives the movement of diverse cargoes, and it has been proposed that specific kinesin light chain (KLC) isoforms target kinesin-1 to these different structures. Here, we test this hypothesis using two in vitro motility assays, which reconstitute the movement of rough endoplasmic reticulum (RER) and vesicles present in a Golgi membrane fraction. We generated GST-tagged fusion proteins of KLC1B and KLC1D that included the tetratricopeptide repeat domain and the variable C-terminus. We find that preincubation of RER with KLC1B inhibits RER motility, whereas KLC1D does not. In contrast, Golgi fraction vesicle movement is inhibited by KLC1D but not KLC1B reagents. Both RER and vesicle movement is inhibited by preincubation with the GST-tagged C-terminal domain of ubiquitous kinesin heavy chain (uKHC), which binds to the N-terminal domain of uKHC and alters its interaction with microtubules. We propose that although the TRR domains are required for cargo binding, it is the variable C-terminal region of KLCs that are vital for targeting kinesin-1 to different cellular structures.

Inhibition of PP2A by LIS1 increases HIV-1 gene expression

Background

Lissencephaly is a severe brain malformation in part caused by mutations in the LIS1 gene. LIS1 interacts with microtubule-associated proteins, and enhances transport of microtubule fragments. Previously we showed that LIS1 interacts with HIV-1 Tat protein and that this interaction was mediated by WD40 domains of LIS1. In the present study, we analyze the effect of LIS1 on Tat-mediated transcription of HIV-1 LTR.

Results

Tat-mediated HIV-1 transcription was upregulated in 293 cells transfected with LIS1 expression vector. The WD5 but not the N-terminal domain of LIS1 increases Tat-dependent HIV-1 transcription. The effect of LIS1 was similar to the effect of okadaic acid, an inhibitor of protein phosphatase 2A (PP2A). We then analyzed the effect of LIS1 on the activity of PP2A in vitro. We show that LIS1 and its isolated WD5 domain but not the N-terminal domain of LIS1 blocks PP2A activity.

Conclusion

Our results show that inhibition of PP2A by LIS1 induces HIV-1 transcription. Our results also point to a possibility that LIS1 might function in the cells as a yet unrecognized regulatory subunit of PP2A.

Survivin inhibits apoptosis induced by TRAIL, and the ratio between survivin and TRAIL receptors is predictive of recurrent disease in neuroblastoma

PURPOSE

Novel treatment strategies for high-risk and disseminated neuroblastoma (NB) are actively sought because of the dismal prognosis of advanced stage disease. Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is a recently identified member of the tumor necrosis factor family. TRAIL is capable of inducing apoptosis in multiple tumor cell types, with little or no cytotoxicity against normal cells.

EXPERIMENTAL DESIGN

We examined the activation and regulation of TRAIL-induced apoptosis in several human NB cell lines. The effect of TRAIL was examined in the context of TRAIL receptor (TRAIL-R) and survivin (an antiapoptotic protein) expression in the cell lines. The ratio of survivin/TRAIL-R messenger RNA was determined and evaluated as a marker of recurrent disease in patients with NB.

RESULTS

TRAIL induced apoptotic cell death of NB with variable sensitivities among the cell lines tested. Compared with a sensitive cell line (early passage NB16), the resistant cell lines (NB7 and late passage NB16) expressed lesser amounts of the death-inducing TRAIL-R1 and R2, and greater levels of survivin, an inhibitor of apoptosis. TRAIL sensitivity was enhanced in resistant cell lines by treating with etoposide that concomitantly increased TRAIL-R expression and diminished survivin expression. Survivin overexpression in a TRAIL-sensitive NB line (early passage NB16) rendered it less sensitive to treatment with TRAIL. Conversely, inhibiting survivin expression in NB3 by antisense oligonucleotides enhanced TRAIL sensitivity. A high survivin/TRAIL-R ratio accurately predicted risk for recurrent disease in primary tumor specimens tested.

CONCLUSIONS

These findings suggest that TRAIL therapy in combination with specific chemotherapeutic agents may represent an effective therapeutic strategy for NB. The cell's sensitivity to TRAIL is at least partially governed by both TRAIL-R and survivin expression, whereas the ratio between these 2 factors appears to have prognostic value in patients with this disease.

Enhancement of Cisplatin sensitivity in squamous cell carcinoma of the head and neck transfected with a survivin antisense gene

OBJECTIVE

To study a new method for treating squamous cell carcinoma of the head and neck using a survivin antisense gene.

DESIGN

An adenoviral vector encoding surviving antisense was used for in vitro and in vivo experiments. KB cells were treated with pAd.CMV[cytomegalovirus]-antisurvivin. Western blot analysis, in vitro cytotoxic assay, and in vivo experiment were performed.

SETTING

In vitro and in vivo study of head and neck cancer cell line KB.

SUBJECTS

Male, 5-week-old BALB/c nude mice.

MAIN OUTCOME MEASURES

Expression of survivin was assessed using Western blot analysis. The effect of antisurvivin to KB cells was measured by cytotoxic assay (in vitro) and tumor volume (in vivo).

RESULTS

In the in vitro experiments, transduction of the survivin antisense gene caused a nearly 12-fold increase in the sensitivity of KB cells to cisplatin, as reflected by the 50% inhibitory concentration. In in vivo experiments in nude mice, tumor growth was more inhibited by the combination of cisplatin and survivin antisense gene transduction compared with either alone.

CONCLUSION

These findings suggest that survivin targeting with adenoviral antisense vectors might be used for selective therapy of squamous cell carcinomas of the head and neck.

Endostatin influences endothelial morphology via the activated ERK1/2-kinase endothelial morphology and signal transduction

Endostatin, the proteolytic fragment of collagen XVIII, is known to be a potent inhibitor of angiogenesis. However, to date, only limited knowledge exists with regard to the effects of endostatin on vessel morphology and the underlying signaling pathway. The aim of the present work was therefore to determine the impact of endostatin and its collagen XV analogue restin on vessel development during wound healing and embryonic angio- and vasculogenesis. Time lapse experiments and electron microscopy demonstrate similar morphological changes evoked by endostatin and the ERK1/2-kinase inhibitor PD98059. Furthermore, we show that ERK1/2 phosphorylation, a crucial signaling event in vascular morphogenesis, is regulated by endostatin via the protein phosphatase 2A PP2A. These findings provide new insight into a key signaling pathway of vascular remodeling evoked by a matrix-derived factor.

Drosophila melanogaster gamma-TuRC is dispensable for targeting gamma-tubulin to the centrosome and microtubule nucleation

In metazoans, γ-tubulin acts within two main complexes, γ-tubulin small complexes (γ-TuSCs) and γ-tubulin ring complexes (γ-TuRCs). In higher eukaryotes, it is assumed that microtubule nucleation at the centrosome depends on γ-TuRCs, but the role of γ-TuRC components remains undefined.

For the first time, we analyzed the function of all four γ-TuRC–specific subunits in Drosophila melanogaster: Dgrip75, Dgrip128, Dgrip163, and Dgp71WD. Grip-motif proteins, but not Dgp71WD, appear to be required for γ-TuRC assembly. Individual depletion of γ-TuRC components, in cultured cells and in vivo, induces mitotic delay and abnormal spindles. Surprisingly, γ-TuSCs are recruited to the centrosomes. These defects are less severe than those resulting from the inhibition of γ-TuSC components and do not appear critical for viability. Simultaneous cosilencing of all γ-TuRC proteins leads to stronger phenotypes and partial recruitment of γ-TuSC. In conclusion, γ-TuRCs are required for assembly of fully functional spindles, but we suggest that γ-TuSC could be targeted to the centrosomes, which is where basic microtubule assembly activities are maintained.

[siRNA against survivin coupling with epirubicin enhances to induce breast cancer cell MCF-7 to apoptosis]

OBJECTIVE

To use the sequence-specific siRNA knocking down the expressions of Survivin gene and inducing breast cancer MCF-7 cell line to apoptosis, and to couple the siRNA with Survivin for investigating the effects of MCF-7 cell induced to apoptosis and the chemotherapy sensitivity of breast cancer cell treated to epirubicin.

METHODS

The molecular cloning technique was applied to construct the eukaryotic expression vector of siRNA against Survivin, and lipofectamine 2000 was used to transfect MCF-7 cell. Survivin expressions were detected by semi-quantitive RT-PCR and immunohistochemical SABC methods. The effects of inducing MCF-7 cell apoptosis and enhanced chemotherapy sensitivity to epirubicin were assessed by TUNEL method.

RESULTS

The sequence-specific siRNA can, effectively and specifically, knock the expressions of Survivin gene down at both mRNA and protein levels, in which the expression inhibition rates were 64.91 and 79.72% respectively. After 48 h, 8.75% cells transfected with siRNA expression vector were induced to apoptosis; Coupling siRNA against Survivin with epirubicin can induce the cell apoptosis rate up to 24.21%.

CONCLUSIONS

In the study, the siRNA against Survivin can, effectively and specifically, decrease the expressions of Survivin gene in MCF-7 cell; blocking the expressions of Survivin can, in certain degree, induce MCF-7 cell to apoptosis and enhance cell chemotherapy sensitivity to epirubicin significantly; Survivin RNAi has a great potential value in the gene therapy of breast cancer.

[Effect of survivin antisense oligodeoxynucleotide on carcinoma of larynx in vivo and in vitro]

OBJECTIVE

To observe the effect of survivin antisense oligodeoxynucleotide (ASODN) on the apoptosis of human carcinoma of larynx cell line Hep2 and the inhibitory rate in nude mice model so as to discuss the selective blocking activity of antisense technique on gene expression seeking a new way for gene therapy of carcinoma of larynx.

METHODS

Antisense oligodeoxynucleotides survivin were transformed into human carcinoma of larynx cell line Hep2 by liposome Lipofectamine 2000. Within 72 h after transfection, 3-(4,5-dimethylthiazol-2-yl) -2,5-diphenyltetrazolium bromide (MTT) assay was used to detect cellular proliferation. Forty eight hours after transfection, reverse transcription-polymerase chain reaction (RT-PCR) assay was used to observe the expression of survivin gene, Western Blot assay for the protein, and terminal deoxynucleotide mediated nick end labeling (TUNEL) and flow cytometer for cellular apoptosis.

RESULTS

Cellular inhibition rate of 72 h went up to 52. 5% and 71.4% at 1.0 micromol/L and 2.0 micromol/L value in Lipo-ASODN groups which differed statistically remarkably (P = 0.046), higher than that in controls in MTT assay (P =0. 003 and 0. 0004). Forty eight hours after transfection survivin gene expression in Lipo-ASODN groups were less than that in control group in RT-PCR assay. Survivin protein expression decreased in Western blot. In TUNEL assay, nuclear positive staining was observed and the apoptosis peak was observed in flow cytometer test, which were absent in controls. In nude mice of carcinoma of larynx model, the inhibitory rate in Lipo-ASODN groups got up to 48.1% and 61.3% higher than that of controls (P < 0.004 and 0. 0006), which differed remarkably (P = 0.032) in a dose-dependently way.

CONCLUSIONS

The findings showed that the expression of survivin gene and protein induced cellular apoptosis in Hep2 cells after transfection of Lipo-ASODN and that the carcinoma of larynx in the nude mice model were inhibited by Lipo-ASODN which suggested that antisense technique can be an effective means in the gene therapy of carcinoma of larynx.

Microtubules and maps

Microtubules are very dynamic polymers whose assembly and disassembly is determined by whether their heterodimeric tubulin subunits are in a straight or curved conformation. Curvature is introduced by bending at the interfaces between monomers. Assembly and disassembly are primarily controlled by the hydrolysis of guanosine triphosphate (GTP) in a site that is completed by the association of two heterodimers. However, a multitude of associated proteins are able to fine-tune these dynamics so that microtubules are assembled and disassembled where and when they are required by the cell. We review the recent progress that has been made in obtaining a glimpse of the structural interactions involved.

Hepatitis B virus X protein upregulates survivin expression in hepatoma tissues

The hepatitis B virus X protein (HBx) plays an important role in the development of hepatocellular carcinoma (HCC). The relationship was examined between HBV antigens and IAP (inhibitor of apoptosis) family in development of HCC. The expression levels of HBV antigens (HBsAg, HBcAg, and HBxAg) and members of the IAP family (survivin, XIAP, cIAP-1, and cIAP-2) were detected immunohistochemically in tissues from 34 cases of HCC and 30 cases of liver cirrhosis. The positive rate of survivin was higher than these three molecules in all three tissue types (P < 0.05). The positive rates of HBxAg and survivin were high in HCC (76.5% and 88.2%), paratumor (85.3% and 91.2%), and liver cirrhosis (100% and 93.3%) tissues, with no significant differences between the survivin- and HBxAg-positive rates (each P > 0.05). To examine the effect of HBx on survivin expression, plasmid pCMV-X (encoding the HBx gene) was transfected transiently with or without plasmid pcDNA3-sur (encoding the survivin gene) into H7402 hepatoma cells and L-O2 human normal liver cells. Cells over-expressing HBx alone showed increased apoptosis along with a dose-dependent increase in survivin levels. However, co-expression of survivin inhibited the HBx-induced apoptosis. To examine the effect of HBx on survivin in hepatoma cells without apoptosis, plasmid pCMV-X was transfected stably into human hepatoma H7402 cells and L-O2 cells. These H7402-X and L-O2-X cells showed high-level expression of both HBx and survivin, but did not show apoptosis. The addition of pSilencer 3.0-X, an RNAi vector targeting the HBx gene, reduced the expression levels of survivin protein in H7402-X cells. Collectively, these data demonstrate that HBx upregulates survivin expression in hepatoma tissues, suggesting that HBx and survivin may both be involved in carcinogenesis of HCC.

[The effect of antisense survivin-liposome complex on cell growth, apoptosis and cell cycle in hepatocellular carcinoma cells]

OBJECTIVE

To investigate the effects and the mechanisms of cell growth inhibition in hepatocellular carcinoma cells after induction with antisense survivin-liposome (LIP) complex, and to provide evidence in treatment for hepatocellular carcinoma and tumors expressing survivin.

METHODS

Survivin ODNs was transfected into HepG2 cells mediated by LiP reagent. The expression of survivin mRNA and protein was detected by RT-PCR and Western blot. MTT assay was applied to determine cell proliferation in HepG2 cells. Active caspase-3 and apoptosis rate were evaluated by flow cytometric analysis. The morphological changes were assessed by electron microscopy. Cell cycle was analyzed by flow cytometry in the cell cycle-synchronized hepatocellular carcinoma cells treated with the antisense compound.

RESULTS

Antisense compound efficiently down-regulated survivin expression (mRNA and protein) in a dose-dependent manner with an IC(50) of 250 nmol/L. Its maximal effect was achieved at a concentration of 600 nmol/L, when expression levels were down-regulated by 80%, as revealed by gradually increase of caspase-3-like protease activity and apoptosis rate in a time-dependent manner. Morphological apoptotic changes such as membrane blebbing, loss of microvilli, cytoplasmic vasculization, condensation of cytoplasm and nucleus, chromatin fragmentation, and apoptosis and cell growth inhibition were observed. In the cell cycle-synchronized hepatocellular carcinoma cells, antisense compound induced cell cycle arrest followed by apoptosis. After treated with low concentration of compound, the cell cycle was arrested at S phase or G2/M phase; while at high concentration, the cell cycle was mainly arrested at S phase. Apoptosis was obviously observed and the rate of apoptosis was increased in a time and concentration-dependent manner.

CONCLUSION

Antisense survivin has significant inhibitory effect on growth of hepatocellular carcinoma cells in vitro. This is associated with cell cycle arrest and apoptosis.

Ganglioside-induced differentiation associated protein 1 is a regulator of the mitochondrial network: new implications for Charcot-Marie-Tooth disease

Mutations in GDAP1 lead to severe forms of the peripheral motor and sensory neuropathy, Charcot-Marie-Tooth disease (CMT), which is characterized by heterogeneous phenotypes, including pronounced axonal damage and demyelination. We show that neurons and Schwann cells express ganglioside-induced differentiation associated protein 1 (GDAP1), which suggest that both cell types may contribute to the mixed features of the disease. GDAP1 is located in the mitochondrial outer membrane and regulates the mitochondrial network. Overexpression of GDAP1 induces fragmentation of mitochondria without inducing apoptosis, affecting overall mitochondrial activity, or interfering with mitochondrial fusion. The mitochondrial fusion proteins, mitofusin 1 and 2 and Drp1(K38A), can counterbalance the GDAP1-dependent fission. GDAP1-specific knockdown by RNA interference results in a tubular mitochondrial morphology. GDAP1 truncations that are found in patients who have CMT are not targeted to mitochondria and have lost mitochondrial fragmentation activity. The latter activity also is reduced strongly for disease-associated GDAP1 point mutations. Our data indicate that an exquisitely tight control of mitochondrial dynamics, regulated by GDAP1, is crucial for the proper function of myelinated peripheral nerves.

[Antisense RNA targeting survivin enhances the chemosensitivity of LOVO/Adr cells to taxotere]

OBJECTIVE

To investigate the ability of antisense RNA eukaryotic expression plasmid pcDNA3.0/survivin targeting survivin gene to inhibit survivin expression and enhance the sensitivity to taxotere in multidrug resistant colon carcinoma cell line LOVO/Adr.

METHODS

The antisense RNA eukaryotic plasmid pcDNA3.0/survivin was transfected into LOVO/Adr cells by lipofectamine. The expression of survivin mRNA was measured using RT-PCR. After treated with taxotere, MTT assay and flow cytometry were used to evaluate the proliferation inhibition and apoptosis of LOVO/Adr cells.

RESULTS

The expression of survivin mRNA in LOVO/Adr cells transfected with pcDNA3.0/survivin was down-regulated in a time- dependent manner. The inhibitory rate of taxotere (0.5 micromol/L) was (37.3 +/- 2.9)% in pcDNA3.0/survivin transfected cells, significantly higher than (21.9 +/- 2.3)% and (21.1 +/- 1.9)% in pcDNA3.0 transfected and untransfected control cells respectively (P< 0.01). The apoptosis rate of taxotere was (28.7 +/- 1.7)% in pcDNA3.0/survivin transfected cells,significantly higher than (13.4 +/- 1.6)% and (14.3 +/- 1.8)% in pcDNA3.0 transfected and untransfected cells respectively.

CONCLUSION

The antisense RNA eukaryotic expression plasmid pcDNA3.0/survivin could down-regulate the expression of survivin gene and enhance the chemosensitivity of LOVO/Adr cells to taxotere, which may provide a novel therapy for colon carcinoma.

[Antisense oligonucleotide targeting survivin induces apoptosis of renal clear-cell carcinoma cells and enhances their sensitivity to epirubicin in vitro]

OBJECTIVE

To investigate the effect of antisense oligonucleotide (ASODN) targeting survivin on the apoptosis and proliferation of renal cancer cell line 786-O and enhancement of its sensitivity to epirubicin.

METHODS

ASODN targeting survivin was designed and constructed. Cultured cells were divided into 6 groups: control group, liposome group, sense oligonucleotide (SODN) group, 600 nmol/L ASODN group, and 600 nmol/L ASODN combined with epirubicin group. After transfected for 24 h, cultured cells were harvested to carry on the next tests. Cell morphological changes were examined by transmission electron microscopy. Survivin protein was detected by immunohistochemical method. Apoptosis index (AI) and proliferation index (PI) were examined by flow cytometry.

RESULTS

Morphological abnormalities of cells were observed in ASODN transfected groups. Expression of survivin in ASODN groups were significantly decreased compared with that in the control group, liposomes group and SODN group. AI of ASODN groups was significantly higher than that in other groups. PI of ASODN groups was significantly lower than that in other groups. The PI of ASODN combined with epirubicin group was (35.7 +/- 1.67)%, but (9.3 +/- 0.34)% or (8.5 +/- 0.21)% in liposomes group or SODN group that had combined with epirubicin. The ASODN group achieved the strongest effects to enhance apoptosis in comparison with control group (P < 0.05), while SODN did not cause statistically significant change (P > 0.05).

CONCLUSION

The expression of survivin protein in the renal clear cell carcinoma cell line 786-O is downregulated by survivin ASODN. ASODN targeting survivin induces apoptosis and inhibits proliferation of 786-O cells. Inhibition of survivin enhances sensitivity of 786-O to epirubicin.

[Survivin antisense oligonucleotide induces human Hep-2 cell apoptosis]

OBJECTIVE

Survivin highly overexpresses in the most of human tumors, and it may play an important role in the development of tumor. The aim of this study was to explore the effects of survivin antisense oligonucleotide (ASODN) on the proliferation and the apoptosis of human Hep-2 cell.

METHODS

Hep-2 cells were transfected with survivin ASODN mediated by lipofectamine, MTT [3-(4,5-dimethylthiazol-2-yl)-2, 5 diphenyl tetrazolium bromide] method was used to observe the cell growth inhibitory rate, the expressions of survivin mRNA and protein were detected by reverse transcriptase polymerase chain reaction (RT-PCR) and Western blot respectively. Flow cytometry was used to examine cell apoptosis rate. Kinase activity test was used to detect the changes of caspase-3 activity.

RESULTS

Survivin ASODN obviously inhibited the cell growth of Hep-2 cells after transfection. After transfected with survivin ASODN the expressions of survivin mRNA and protein of Hep-2 cells were down-regulated, and apoptosis rate was significantly increased. The activity of caspase-3 increased highly in Hep-2 cells transfected with survivin ASODN, which showed time-dependent.

CONCLUSIONS

Survivin ASODN could inhibit the proliferation of Hep-2 cell and induced apoptosis through down-regulating the the expressions of survivin mRNA and protein.

A comparison of the ability of XMAP215 and tau to inhibit the microtubule destabilizing activity of XKCM1

During mitosis, microtubules not only grow fast, but also have a high rate of catastrophe. This is achieved in part by the activity of the MAP, XMAP215, which can stimulate the growth rate of microtubules without fully inhibiting the function of the catastrophe-kinesin XKCM1. We do not know whether this activity is particular to XMAP215, or is a general property of all MAPs. Here, we compare the activities of XMAP215 with the neuronal MAP tau, in opposing the destabilizing activity of the non-conventional kinesin XKCM1. We show that tau is a much more potent inhibitor of XKCM1 than XMAP215. Because tau completely suppresses XKCM1 activity, even at low concentrations, the combination of tau and XKCM1 is unable to generate mitotic microtubule dynamics.

Survivin mediates resistance to antiandrogen therapy in prostate cancer

Resistance to antiandrogen therapy in patients with metastatic prostate cancer poses a major challenge, which, if overcome, may lead to significant advances in the treatment of these patients. Hormone resistance of prostate cancer develops, in part, from upregulation of antiapoptotic genes after androgen deprivation. Given the accumulating evidence that Survivin, a new member of the inhibitor of apoptosis (IAP) family, is associated with both cancer progression and drug resistance, we hypothesized that Survivin plays a potentially important role in hormone therapy resistance, and that targeting of Survivin may enhance sensitivity to antiandrogen therapy in prostate cancer. Patterns of Survivin expression were assessed in three prostate cancer cell lines LNCaP, PC-3, and DU-145 using quantitative Western analysis. All three cell lines were found to strongly express Survivin. In LNCaP cells with intact androgen receptors (ARs), it was observed that androgen stimulation with 5alpha-dihydrotestosterone (DHT) increased Survivin expression. Conversely, treatment with Flutamide decreased Survivin expression in LNCaP cells. We next studied the functional effect of Survivin on sensitivity to Flutamide. LNCaP cells were infected with replication-deficient adenoviruses encoding either wild-type Survivin pAd-S(WT) or a phosphorylation-defective Survivin Thr34 --> Ala dominant-negative mutant pAd-S(T34A), and then treated with Flutamide. Cell viability and apoptosis were assessed in vitro and in vivo. It was determined that Survivin can mediate resistance to such antiandrogen therapies based on our assays. Direct androgen stimulation resulted in pan-cell cycle expression of Survivin, which was found to be mediated by AKT, as it was determined that exogenous insulin-like growth factor-1 (IGF-1), a known activator of AKT signaling, could increase Survivin expression and result in pan-cell cycle expression even in AR-negative prostate cancer cell lines PC-3 and DU-145. Given this alternative mechanism of Survivin expression and our findings that Survivin can mediate resistance to Flutamide treatment, we further investigated whether IGF-1-mediated activation of Survivin via AKT could mediate resistance to antiandrogen therapy. Both in vitro and in vivo, this was found to be the case, supporting a novel mechanism of resistance to antiandrogen therapy. Our study indicates that upregulation of Survivin via IGF-1 signaling confers resistance to Flutamide in prostate cancer cells. Targeted inhibition of Survivin appears to enhance the therapeutic effects of Flutamide in vitro and in vivo, revealing a novel strategy to enhance sensitivity to androgen ablation therapy.

Increased p21(ras) activity in human fibroblasts transduced with survivin enhances cell proliferation

Survivin is critically involved in mitosis and when overexpressed enhances the activity of the Aurora B kinase, a serine-threonine kinase belonging to the family of oncogenic Aurora/IpI1p-related kinases. Both proteins interact with Ras GTPase-activating protein suggesting an impact on the Ras pathway. This study aimed at defining the role of survivin in proliferation and potential transformation of cells. When survivin was overexpressed in normal human lung fibroblasts, the characteristic track lanes of fibroblasts were disturbed and the rate of cell proliferation was increased. An enhanced level of p21(ras) mRNA and protein expression and concomitant rise in levels of activated p21(ras) were observed. Despite increased proliferation cell survival remained dependent on serum and cells were not able to form colonies in soft agar assays. These data suggest that overexpression of survivin increases cell growth but, despite the increase in active p21(ras), is not sufficient to transform primary cells. Yet, in addition to its anti-apoptotic function it might contribute to the accelerated growth of tumour cells by increasing p21(ras) activity.

GEC1, a protein related to GABARAP, interacts with tubulin and GABA(A) receptor

We have previously identified in uterine cells a novel estrogen-regulated gene called gec1. GEC1 presents 87% identity with GABARAP which, so far, was the only protein found to associate with tubulin and GABA(A) receptor. We demonstrated then that GEC1 interacts in vitro with tubulin and GABA(A) receptor, and promotes tubulin assembly and microtubule bundling. Since all polyclonal antibodies failed in discrimination of both proteins GEC1 and GABARAP, a GEC1-GFP fusion protein was used to specifically localize GEC1. GEC1-GFP was distributed over the cytoplasm in perinuclear vesicles with a scattered pattern. Overall, our data show that GEC1 could be a new member of the GABARAP family involved in the transport of GABA(A) receptor.

Eg5 causes elongation of meiotic spindles when flux-associated microtubule depolymerization is blocked

In higher eukaryotes, microtubules (MT) in both halves of the mitotic spindle translocate continuously away from the midzone in a phenomenon called poleward microtubule flux. Because the spindle maintains constant length and microtubule density, this microtubule translocation must somehow be coupled to net MT depolymerization at spindle poles. The molecular mechanisms underlying both flux-associated translocation and flux-associated depolymerization are not well understood, but it can be predicted that blocking pole-based destabilization will increase spindle length, an idea that has not been tested in meiotic spindles. Here, we show that simultaneous addition of two pole-disrupting reagents p50/dynamitin and a truncated version of Xklp2 results in continuous spindle elongation in Xenopus egg extracts, and we quantitatively correlate this elongation rate with the poleward translocation of stabilized microtubules. We further use this system to demonstrate that this poleward translocation requires the activity of the kinesin-related protein Eg5. These results suggest that Eg5 is responsible for flux-associated MT translocation and that dynein and Xklp2 regulate flux-associated microtubule depolymerization at spindle poles.

[Effect of survivin targeting on cell proliferation and apoptosis in pancreatic cancer cells]

OBJECTIVE

To investigate the effects of antisense survivin-Lip compound on pancreatic cancer cell proliferation and apoptosis and its mechanism.

METHODS

Pancreatic cancer cells of the line PANC-1 were cultured. Survivin oligonucleotide (ODN) was transfected into the PANC-1 cells mediated by Lip reagent. The expression of survivin mRNA and that of surviving protein were detected by RT-PCR and Western blotting. MTT assay was applied to determine the proliferation of PANC-1 cells. Active caspase-3 and apoptosis rate were evaluated by flow cytometric analysis. The morphological changes were assessed by electron microscope. Lascar scanning confocal microscope immunofluorescence analysis was performed to detect the subcellular localization of survivin protein on treated cells and untreated cells.

RESULTS

Antisense compound efficiently down-regulated the survivin expression (mRNA and protein) in dose-dependent manner with an IC50 of 300 nmol/L. Its maximum effect was achieved at the concentration of 500 nM, at which the expression level was down-regulated by 80%. The similar results were found in MTT assay. As revealed by gradually increased caspase-3-like protease activity and apoptosis rate in a time-dependent manner, and the morphological changes of apoptosis such as blebbing and loss of microvilli, vacualization in cytoplasm, condensation of cytoplasm and nucleus, and fragmented chromatin, treatment with antisense compound induced apoptosis and inhibited cell growth. Fluororescein isothiocyanate (FITC)-labeled immunofluorescence staining of survivin clearly showed that survivin was expressed mainly in the formation of a spotted distribution inside the cytoplasm of untreated cells. Survivin protein molecules were clearly seen in the cytoplasm of the untransfected cells and distributed like spots and almost disappeared in the transfected cells with morphological changes conforming to the changes of apoptosis.

CONCLUSION

Survivin protein is a key molecular connecting proliferation with apoptosis and antisense oligonucleotides targeting survivin have a bright prospect in therapy of pancreatic cancer cells.

Distinct roles of group III metabotropic glutamate receptors in control of nociception and dorsal horn neurons in normal and nerve-injured Rats

Increased glutamatergic input to spinal dorsal horn neurons constitutes an important mechanism for neuropathic pain. However, the role of group III metabotropic glutamate receptors (mGluRs) in regulation of nociception and dorsal horn neurons in normal and neuropathic pain conditions is not fully known. In this study, we determined the effect of the group III mGluR specific agonist L(+)-2-amino-4-phosphonobutyric acid (L-AP4) on nociception and dorsal horn projection neurons in normal rats and a rat model of neuropathic pain. Tactile allodynia was induced by ligation of L5/L6 left spinal nerves in rats. Allodynia was determined by von Frey filaments in nerve-injured rats. The nociceptive threshold was tested using a radiant heat and a Randall-Selitto pressure device in normal rats. Single-unit activity of ascending dorsal horn neurons was recorded from the lumbar spinal cord in anesthetized rats. An intrathecal (5-30 microg) L-AP4 dose-dependently attenuated allodynia in nerve-injured rats but had no antinociceptive effect in normal rats. Topical spinal application of 5 to 50 microM L-AP4 also significantly inhibited the evoked responses of ascending dorsal horn neurons in nerve-ligated but not normal rats. Furthermore, blockade of spinal group III mGluRs significantly decreased the withdrawal threshold and increased the evoked responses of dorsal horn neurons in normal but not nerve-injured rats. These data suggest that group III mGluRs play distinct roles in regulation of nociception and dorsal horn neurons in normal and neuropathic pain states. Activation of spinal group III mGluRs suppresses allodynia and inhibits the hypersensitivity of dorsal horn projection neurons associated with neuropathic pain.

Inflammation-associated cell cycle-independent block of apoptosis by survivin in terminally differentiated neutrophils

Survivin has received great attention due to its expression in many human tumors and its potential as a therapeutic target in cancer. Survivin expression has been described to be cell cycle–dependent and restricted to the G₂-M checkpoint, where it inhibits apoptosis in proliferating cells. In agreement with this current view, we found that survivin expression was high in immature neutrophils, which proliferate during differentiation. In contrast with immature cells, mature neutrophils contained only little or no survivin protein. Strikingly, these cells reexpressed survivin upon granulocyte/macrophage colony-stimulating factor (CSF) or granulocyte CSF stimulation in vitro and under inflammatory conditions in vivo. Moreover, survivin-deficient mature neutrophils were unable to increase their lifespan after survival factor exposure. Together, our findings demonstrate the following: (a) overexpression of survivin occurs in primary, even terminally differentiated cells and is not restricted to proliferating cells; and (b) survivin acts as an inhibitor of apoptosis protein in a cell cycle–independent manner. Therefore, survivin plays distinct and independent roles in the maintenance of the G₂-M checkpoint and in apoptosis control, and its overexpression is not restricted to proliferating cells. These data provide new insights into the regulation and function of survivin and have important implications for the pathogenesis, diagnosis, and treatment of inflammatory diseases and cancer.

Positioning the Golgi apparatus

Ríos et al. (2004) report in this issue that the Golgi protein GMAP-210 is sufficient to confer pericentrosomal positioning and recruits gamma-tubulin and associated microtubule-nucleating ring complex proteins to Golgi membranes. The results raise the possibility that short microtubules emanate from the Golgi to mediate its organization and positioning.

Complementary roles for dynein and kinesins in the Xenopus egg cortical rotation

Aligned vegetal subcortical microtubules in fertilized Xenopus eggs mediate the "cortical rotation", a translocation of the vegetal cortex and of dorsalizing factors toward the egg equator. Kinesin-related protein (KRP) function is essential for the cortical rotation, and dynein has been implicated indirectly; however, the role of neither microtubule motor protein family is understood. We examined the consequence of inhibiting dynein--dynactin-based transport by microinjection of excess dynamitin beneath the vegetal egg surface. Dynamitin introduced before the cortical rotation prevented formation of the subcortical array, blocking microtubule incorporation from deeper regions. In contrast, dynamitin injected after the microtubule array was fully established did not block cortical translocation, unlike inhibitory-KRP antibodies. During an early phase of cortical rotation, when microtubules showed a distinctive wavy organization, dynamitin disrupted microtubule alignment and perturbed cortical movement. These findings indicate that dynein is required for formation and early maintenance of the vegetal microtubule array, while KRPs are largely responsible for displacing the cortex once the microtubule tracks are established. Consistent with this model for the cortical rotation, photobleach analysis revealed both microtubules that translocated with the vegetal cytoplasm relative to the cortex, and ones that moved with the cortex relative to the cytoplasm.

The role of microtubule-associated protein 2c in the reorganization of microtubules and lamellipodia during neurite initiation

During neurite initiation, cells surrounded by a flattened, actin-rich lamellipodium transform to produce thin, microtubule-filled neurite shafts tipped by actin-rich growth cones, but little is known about this transformation. Our detailed time-lapse analyses of cultured hippocampal neurons, a widely used model system for neuronal development, revealed that neurites emerge from segmented lamellipodia, which then gradually extend from the cell body to become nascent growth cones. This suggests that actin- and microtubule-rich structures are reorganized in a coordinated manner. We hypothesized that proteins such as microtubule-associated protein 2 (MAP2), which can interact with both cytoskeletal components, might be critically involved in neurite initiation. Live-cell video and fluorescence microscopy in Neuro-2a cells showed that expression of MAP2c triggers neurite formation via rapid accumulation and bundling of stable, MAP2c-bound microtubules, concurrent with a gradual transformation of lamellipodia into nascent growth cones. The microtubule-stabilizing agent Taxol did not mimic this effect, suggesting that the ability of MAP2c to stabilize microtubules is not sufficient for neurite initiation. However, combination of Taxol treatment with actin disruption induced robust process formation, suggesting that inhibitory effects of F-actin need to be overcome as well. Neurite initiation by MAP2c required its microtubule-binding domain and was enhanced by its binding domain for cAMP-dependent protein kinase (PKA). MAP2c mutants defective in both PKA and microtubule binding acted as dominant negative inhibitors of neurite initiation in neuroblastoma cells and primary hippocampal neurons. Together, these data suggest that MAP2c bears functions that both stabilize microtubules and directly or indirectly alter actin organization during neurite initiation.

The topoisomerase I inhibitor topotecan increases the sensitivity of prostate tumor cells to TRAIL/Apo-2L-induced apoptosis

PURPOSE.:TRAIL/Apo-2L is cytotoxic against numerous prostate tumor cell lines; however, some lines are more resistant than others. Identification of an agent that increases prostate tumor cell sensitivity to TRAIL/Apo-2L would prove valuable for TRAIL/Apo-2L-mediated tumor therapy. Thus, we examined the effect of combining five clinically approved chemotherapeutic agents with TRAIL/Apo-2L for treating prostate tumor cells.

METHODS

Four human prostate tumor cell lines were initially tested for TRAIL/Apo-2L sensitivity. Subsequent studies examined whether the TRAIL/Apo-2L-induced killing of DU-145 cells was augmented in the presence of the chemotherapeutic molecules, as measured by annexin V-FITC/propidium iodide staining. Furthermore, caspase 8 activation and BID cleavage were examined by immunoblotting. RT-PCR and flow cytometry were performed to monitor TRAIL-R1 and TRAIL-R2 levels after chemotherapeutic treatment.

RESULTS

DU-145 cells were the least responsive of the prostate tumor cell lines tested to TRAIL/Apo-2L-induced death. Surprisingly, only topotecan, a topoisomerase I inhibitor, when used in combination with rTRAIL/Apo-2L led to significant apoptosis of DU-145 cells, as measured by caspase 8 activation, BID cleavage, and annexin V-FITC/PI staining. Topotecan alone had little to no toxicity on the DU-145 cells. Furthermore, the increase in TRAIL/Apo-2L sensitivity following topotecan treatment correlated with increased expression of TRAIL-R1 and TRAIL-R2 and decreased intracellular levels of the antiapoptotic protein survivin.

CONCLUSIONS

Our results define a promising direction for alternative therapies against androgen-independent prostate cancers. The sensitivity of DU-145 cells to TRAIL/Apo-2L was dramatically increased when combined with topotecan, suggesting that low-dose topotecan treatment to upregulate TRAIL-R1 and TRAIL-R2 and downregulate survivin, followed by TRAIL/Apo-2L administration, may be a viable therapy for treating cancer of the prostate.

The apoptosis inhibitor protein survivin induces tumor-specific CD8+ and CD4+ T cells in colorectal cancer patients

The identification of tumor-associated antigens expressed by colorectal carcinoma remains one of the major goals for designing novel immunological treatments for this tumor. By using a reverse-immunology approach, we show here that the inhibitor of apoptosis protein, survivin, is immunogenic in colorectal cancer patients. In particular, we found that survivin elicited CD8(+) T cell-mediated responses in peripheral blood or in tumor-associated lymphocytes from patients at different disease stage. Colorectal carcinoma cells were recognized by survivin-specific T lymphocytes, and the survivin-specific, class-I HLA-restricted T lymphocytes were fully activated and released interleukin-2 in response to HLA/survivin-peptide complexes expressed by tumor cells. In addition to CD8-mediated responses, survivin specifically stimulated CD4+ T-cell reactivity in peripheral blood lymphocytes from the same patients, thus suggesting that a complete activation of the immune system may occur in response to this antiapoptotic protein. These findings indicate that survivin could be considered a valuable tumor-associated antigen for immune-based clinical approaches in colorectal cancer.

Survivin and aven: two distinct antiapoptotic signals in acute leukemias

BACKGROUND

Antiapoptotic signals are important in the development, progression and prognosis of malignant tumors. The aim of this study was to determine the two distinct antiapoptotic signals-survivin and aven-in acute leukemias and compare them with clinical and hematological findings and response to therapy. Real-time quantitative PCR was used and survivin and aven were detected at the messenger (m)RNA level.

PATIENTS AND METHODS

Sixty-five patients with acute leukemia [37 with acute myeloblastic leukemia (AML) and 28 with acute lymphoblastic leukemia (ALL)] were used as the study group and 10 healthy subjects were used as the control group.

RESULTS

Survivin was between 0.0 and 0.829 copy number/cell (median 0.0721, mean 0.5424301909 +/- 0.139799488589) and aven was between 0.0 and 0.853 copy number/cell (median 0.0124, mean 0.070335542 +/- 0.1524685709). We found an important association between survivin and aven (P = 0.000). Both survivin and aven were higher in the study group than in the controls (P = 0.001 and 0.035, respectively). When we compared survivin and aven with other clinical and hematological parameters, there was an important association between survivin and extramedullary involvement (P = 0.033), survivin and alkaline phosphatase (P = 0.06), white blood cell (WBC) count and lactate dehydrogenase (LDH) (P = 0.000), WBC count and uric acid (P = 0.074), hemoglobin level and LDH (P = 0.072), LDH and uric acid (P = 0.057), CD7 expression and survivin (P = 0.097), and CD34 expression and aven (P = 0.058). Response to therapy was evaluated according to the survivin and aven levels. Survivin level was lower in refractory patients as compared with complete responders (P = 0.085). Aven level was higher in patients with relapse as compared with non-relapse patients (P = 0.04). There was no important association between survivin or aven and performance status, lymphadenopathy or organomegaly.

CONCLUSIONS

Both survivin and aven are important antiapoptotic signals in acute leukemias, and the association between extramedullary involvement, CD7 expression and CD34 expression, which are important poor prognostic indicators in acute leukemias, suggests that survivin and/or aven may be novel prognostic indicators in acute leukemias. Further studies with a higher number of patients will be more informative.

Procaspase 3 expression in ovarian carcinoma cells increases survivin transcription which can be countered with a dominant-negative mutant, survivin T34A; a combination gene therapy strategy

Increased survivin expression is a negative prognostic marker in many tumours, including ovarian cancer. We show here that ovarian carcinoma cells upregulate survivin transcription in response to increased expression of the proapoptotic protein procaspase 3. We have utilized this observation in a combination gene therapy strategy using adenoviral constructs expressing the dominant-negative mutant survivin T34A (Ad Survivin T34A) and procaspase 3 (Ad Caspase 3) in ovarian carcinoma cell lines. Transfection of ovarian carcinoma cells with Ad Survivin T34A induces apoptosis via a caspase 9-mediated pathway that is not affected by cell cycle block prior to G2/M. Ad Survivin T34A-induced apoptosis can be significantly enhanced by cotransfection with Ad Caspase 3, and the combination of Ad Survivin T34A and Ad Caspase 3 leads to a significant increase in survival in a murine intraperitoneal ovarian carcinoma model with some long-term survivors. This suggests that inhibiting endogenous survivin activity while also delivering high levels of procaspase 3 allow proteolytic cleavage and activation of the terminal caspase cascade leading to tumour cell death.

Identification of XMAP215 as a microtubule-destabilizing factor in Xenopus egg extract by biochemical purification

Microtubules (MTs) polymerized with GMPCPP, a slowly hydrolyzable GTP analogue, are stable in buffer but are rapidly depolymerized in Xenopus egg extracts. This depolymerization is independent of three previously identified MT destabilizers (Op18, katanin, and XKCM1/KinI). We purified the factor responsible for this novel depolymerizing activity using biochemical fractionation and a visual activity assay and identified it as XMAP215, previously identified as a prominent MT growth-promoting protein in Xenopus extracts. Consistent with the purification results, we find that XMAP215 is necessary for GMPCPP-MT destabilization in extracts and that recombinant full-length XMAP215 as well as an NH2-terminal fragment have depolymerizing activity in vitro. Stimulation of depolymerization is specific for the MT plus end. These results provide evidence for a robust MT-destabilizing activity intrinsic to this microtubule-associated protein and suggest that destabilization may be part of its essential biochemical functions. We propose that the substrate in our assay, GMPCPP-stabilized MTs, serves as a model for the pause state of MT ends and that the multiple activities of XMAP215 are unified by a mechanism of antagonizing MT pauses.

[The signal transduction pathway related to hepatocellular carcinoma apoptosis induced by survivin antisense oligonucleotide]

OBJECTIVE

The expression of survivin gene in hepatocellular carcinoma cell line SMMC-7721 was blocked by means of antisense oligonucleotide (ASODN) transfection. To investigate the signal transduction pathway of apoptosis induced by survivin ASODN.

METHODS

survivin ASODN was transfected into SMMC-7721 cells mediated by DOTAP liposomal reagent. The expression of survivin protein and mRNA was detected by western-blot and in situ hybridization method, respectively. Flow cytometer and TUNEL method were used to detect apoptosis. The changes in the expression and activity of p38MAPK and caspase-3 were assessed by western-blot, immuno-precipitation, RT-PCR, and kinase activity assess to study the relationship between the changes of p38MAPK and caspase-3 activity.

RESULTS

The expression of survivin protein and mRNA decreased 84.6% and 69.7% respectively while apoptosis increased from 0.70% to 31.15% after transfected with survivin ASODN. P38MAPK activity increased significantly followed by increasing of caspase-3 activity after survivin ASODN transfection. Both p38MAPK and caspase-3 activity were inhibited after treated with inhibitor of p38MAPK, SB202190.

CONCLUSION

Transfection of survivin ASODN could induce hepatocellular carcinoma cells apoptosis effectively through activated p38MAPK-caspase-3 signal pathway sequentially.