Peg3/Pw1 promotes p53-mediated apoptosis by inducing Bax translocation from cytosol to mitochondria

Mitochondria is believed to play a central role in p53-mediated apoptosis. However, the signal transduction pathways leading to mitochondria remain unclear. Here, we report that translocation of Bax protein from cytosol to mitochondria is required for p53-induced apoptosis. Cytosolic Bax is unable to induce apoptosis, and blocking Bax translocation inhibits cell death. Expression of Bcl-2 blocks cytochrome c release and apoptosis but has no effect on Bax translocation, suggesting that Bax translocation acts upstream of Bcl-2. We further demonstrate that Peg3/Pw1, a protein up-regulated in p53-mediated cell death process, induces Bax translocation independent of apoptosis. The results suggest that Bax translocation represents an important regulatory step in p53-mediated apoptosis, and Peg3/Pw1 functions as a modulator downstream of p53 to regulate Bax redistribution in the cells, thus favoring the cellular decision toward apoptosis over growth arrest following p53 induction.

Tumor-specific recognition of human myeloma cells by idiotype-induced CD8(+) T cells

Immunoglobulin secreted by myeloma cells contains a unique antigenic determinant (idiotype [Id]) that may serve as a tumor-specific antigen. Although Id-protein-specific T-cell responses have been reported in patients with myeloma, it is not known whether primary myeloma tumor cells can present naturally processed Id peptides on their surface as a target. We immunized 2 healthy human stem-cell donors with Id proteins from their recipients. T cells from the immunized donors released high levels of T-helper 1-type cytokines in response to stimulation with myeloma cells from their recipients. The T-cell-mediated cytokine response to tumor cells was blocked by a major histocompatibility complex (MHC) class I monoclonal antibody, whereas the response to soluble Id protein was dependent on MHC class II. To investigate whether Id-specific CD8(+) T cells can recognize and kill autologous myeloma cells, we generated T cells from peripheral blood mononuclear cells from a third patient with myeloma by means of in vitro stimulation with autologous dendritic cells pulsed with Id protein. Tumor-specific lysis of myeloma cells was demonstrated by the lack of killing of autologous nonmalignant B cells or natural killer-sensitive K562 cells. Lysis of autologous myeloma targets was restricted by MHC class I molecules. These data represent the first report of class I-restricted T-cell recognition of fresh autologous myeloma targets and formally demonstrate that human myeloma cells can serve as targets of an Id-specific T-cell response. (Blood. 2000;96:2828-2833)

Total synthesis of oxidized phospholipids. 3. The (11E)-9-hydroxy-13-oxotridec-11-enoate ester of 2-lysophosphatidylcholine

A total synthesis of (11E)-9-hydroxy-13-oxotridec-11-enoate ester of 2-lysophosphatidylcholine (HOT-PC) was devised to facilitate identification of this oxidized phospholipid. A lactone, 8-(3-oxo-1H,6H-2-oxinyl)octanoic acid (1), believed to be generated through an intermediate (11E)-9-hydroxy-13-oxotridec-11-enoic acid (HOT), is produced upon autoxidation of linoleic acid. A synthesis of lactone 1 methyl ester was accomplished from HOT involving a novel trans-cis isomerization that is driven to completion by cyclization to a hemiacetal. An alternative route to this carbon skeleton was also achieved that provides the lactone 1 itself.

[Precise map of allelic loss on chromosome 3p14 in nasopharyngeal carcinoma]

OBJECTIVE

To determine the precise allelic loss on chromosome 3p14 and discuss the possible relations between loss of heterozygosity (LOH) and EBV infection, clinical stage and clinic-pathology of nasopharyngeal carcinoma (NPC).

METHODS

Six high dense microsatellite marker on chromosome 3p14 were selected to examine LOH in 32 cases of NPC.

RESULTS

23 of 32 (71.9%) tumors were deleted for at least one locus of six loci. High frequencies of LOH (> 40%) were observed at loci D3S1300(50.0%), D3S1313(46.4%) and D3S1312(44.4%). 12 cases showed LOH in one contiguous and nonrandom region. The smallest common deletion region seems likely to lie between D3S1313 and D3S1312. Relations between LOH on 3p14 and clinical stage and EBV infection were observed. The frequency of LOH was 70.0% in 30 cases of poor-differentiated squamous cell carcinoma. 2 cases of vesicular nucleus cell carcinoma had LOH at two loci.

CONCLUSION

The high deletion rate on 3p14 in NPC indicates that there might be a putative tumor suppressor gene related to the development and progression of NPC.

New aspects to event-synchronous cancellation of ECG interference: an application of the method in diaphragmatic EMG signals

An "event-synchronous interference canceller" (ESC) for cancellation of electrocardiographic (ECG) interference in diaphragmatic electromyographic (EMGdi) signals is addressed in this paper. ESC pursues the concept of the "event synchronous adaptive interference canceller" (ESAIC), which was proposed in [1] as a specific application of the well known "adaptive noise canceller" (ANC) paradigm, but ESC uses a simple adaptive gain control (AGC) instead of the complex adaptive filter of the ANC. The proposed ESC method is evaluated using both computer simulations and real EMGdi data, and its efficiency in interference cancellation is compared to that of ESAIC. Of particular interest is the result that the ESC can replace the ESAIC providing better performance as well as a considerable reduction of computational costs.

[Studies on the mechanisms of developmental toxicity of alcohol]

OBJECTIVE

To study the mechanisms of developmental toxicity in animals induced by ethyl alcohol.

METHOD

Rat embryos of 9.5 days of gestation were exposed to different doses of ethyl alcohol in vitro. Postimplantation whole embryo culture and fluorescence polarization technique were used to investigate the effects of alcohol on embryo development and visceral yolk sac (VYS) membrane lipid fluidity.

RESULT

400 mg alcoho/L caused no significant differences to embryo development, organ morphological scores, polarization (Pr value) and lipid fluidity unit (LFU), as compared with the non-alcohol treated controls. 1,000 mg alcohol/L led to the decrease of scores of brain, VYS circle, neurotube, head length and heart, as well as DNA and Pr value; whereas LFU values were increased significantly. Above 2,000 mg alcohol/L, all indexes were decreased except LFU of VYS cell membrane. Alcohol significantly elevated lipid fluidity of VYS cell membrane.

CONCLUSIONS

Alcohol causes development toxicity and teratogenisis in rats. Brain and VYS are the targets of alcohol effect. Its development toxicity is related with lipid fluidity and the VYS membrane damage.

New antimicrobial flavanones from Physena madagascariensis

Two new flavanones (1 and 2) with antibacterial activity were isolated from the methanolic extract of the dried leaves of Physena madagascariensis using activity against Staphylococcus aureus to guide the isolation. A third flavonoid, a flavanone dimer linked by a methylene group (3) was also isolated and proved to be inactive. The structures of 1 and 2 were established primarily from NMR studies, while that of 3 required more extensive mass spectrometric analysis. All three flavanones had lavandulyl units in the limonene form. Flavanones 1 and 2 were active against several bacteria at concentrations as low as 4 microM.

Dot-immunobinding assay using indirect photoacoustic measurement

Dot-immunobinding assay of hepatitis B surface antigen (HBsAg) was performed by a conventionally dot-ELISA technique with 4-chloro-1-naphthol staining, and the quantitative results were measured by an indirect photoacoustic method. In this method, a 2-mW helium-neon laser was applied to provide the excitation beam, the blue spots on the membrane were detected in a piezoelectric transducer-based photoacoustic cell. The operational conditions of measurement were optimized. A significant difference from the negative human serum was obtained for 50 pg in HBsAg detection. The method proposed provides a sensitive quantitative technique for dot-immunobinding assay.

[The effects of RA538 and antisense c-myc on cervical cancer cell lines with high expression of bcl-2 gene]

OBJECTIVE

To study the effects of recombinant adenovirus with RA538 or antisense c-myc insert on cervical cancer cell lines with high expression of bcl-2 gene.

METHODS

Cervical cancer cell lines HeLa and SiHa were transduced with full length bcl-2 cDNA by lipofectin and cell clones with stable expression of bcl-2 were selected. They were then transfected with recombinant adenovirus containing RA538 (Ad-RA538), antisense c-myc (Ad-ASc-myc) or LacZ (Ad-LacZ) gene. Morphologic and molecular changes of the transfected cancer cells were examined by light microscopy, MTT, RT-PCR and Northern blot.

RESULTS

The bcl-2 cDNA was successfully transferred into HeLa and SiHa cells. Two cell lines, called HeLa-bcl2 and SiHa-bcl2 with high expression of bcl-2 gene were generated. Ad-RA538 and Ad-ASc-myc transfection both could inhibit cell growth and induce apoptosis of HeLa and SiHa cells, and inhibit their expression of c-myc and bcl-2 genes. However, although Ad-RA538 and Ad-ASc-myc had some inhibitory effect on bcl-2 and c-myc gene expression by HeLa-bcl2 and SiHa-bcl2 cells, they could only slightly inhibit cell growth and weakly induce apoptosis.

CONCLUSION

Ad-RA538 and Ad-ASc-myc can to certain extent inhibit cell growth and induce apoptosis of two cervical cancer cell lines. They have little such effect when these cell lines have over-expressed bcl-2 by transduction of exogenous bcl-2 gene.

[Sarcomatoid carcinoma in breast]

OBJECTIVE

To observe the distinctive pathomorphological features of sarcomatoid carcinoma (SC) in mammary gland as well as its diagnosis and differential diagnosis.

METHODS

1 538 malignant tumors of the breast were reviewed. 15 cases (0.98%) were diagnosed as SC. AE1/AE3, carcinoembryonic antigen (EMA), vimentin, S-100 protein, actin, estrogen receptor (ER) and progesterone (PR) were performed with SP immunohistochemical staining methods.

RESULTS

The SC were divided into four morphological types according to the distinctive features of their sarcomatoid components. (1) Polymorphic sarcoma type: sarcomatoid components are polymorphic; (2) Spindle cell type: sarcomatoid components consisted of spindle cells; (3) Osteoclastic giant cell type: a huge number of osteoclastic giant cells in the sarcomatoid components; (4) Myxocartilage type: myxocartilaginoid components are seen in the tumor tissue. With immunohistochemical staining, the expression rates of AE1/AE3, EMA, vimentin, S-100 protein and actins in the epithelial components were in 11, 15, 11, 12 and 8 cases respectively, and sarcomatoid components were in 10, 13, 13, 13 and 10 cases respectively, while ER and PR were positive only in 2 cases.

CONCLUSION

Sarcomatoid carcinoma of the breast should be distinguished from carcinosarcoma, desmoplastic carcinoma, sarcoma, nodular fasciitis and fibromatosis.

An unusual foreign body in the tongue

A T-shaped metal object from an umbrella embedded in the tongue of a 4-year-old male child is described, along with its subsequent removal. The types of foreign bodies reported in this area are also mentioned.

[The relationship of expression of CD44v6 with metastasis and prognosis in breast cancer]

OBJECTIVE

To study the relationship of expression of CD44v6 with metastasis and prognosis in breast cancer.

METHODS

The expression of CD44v6 protein in 78 paraffin and 37 fresh specimens of breast carcinomas was detected with immunohistochemistry (IHC). The expression of CD44v6 mRNA in 37 fresh specimens of breast carcinoma was detected with RT-PCR. The correlation of tumor size, TNM stage, status of axillary lymph node, tissue grade, prognosis and CD44v6 expression in breast cancer was analyzed to compare the sensitivity of the two methods.

RESULTS

The expression of CD44v6 in breast cancer was correlated to metastasis of the axillary lymph node, tumor size and TNM stage. It was an important factor affecting survival of patients with breast cancer. Positive expressive rates of CD44v6 protein and mRNA were 70.3% and 59.5% respectively in 37 specimens of fresh carcinoma tissues (P > 0.05).

CONCLUSIONS

The expression of CD44v6 is closely related to metastasis and prognosis in breast cancer, and the sensitivity to detect CD44v6 expression shows no significant difference between IHC and RT-PCR.

Potential cytotoxic effect of chronic administration of creatine, a nutrition supplement to augment athletic performance

Creatine is alleged to be an ergogenic aid to enhance sports performance and recently became a popular sports nutrition supplement. Although short-term supplementation of creatine has not been associated with major health risks, the safety of prolonged use has caused some concern. The present study demonstrates that creatine is metabolized to methylamine, which is further converted to formaldehyde by semicarbazide-sensitive amine oxidase (SSAO). Formaldehyde is well known to cross-link proteins and DNAs, and known to be a major environmental risk factor. SSAO-mediated production of toxic aldehydes has been recently proposed to be related to pathological conditions such as vascular damage, diabetic complications, nephropathy, etc. Chronic administration of a large quantity of creatine can increase the production of formaldehyde, which may potentially cause serious unwanted side-effects.

[Arsenic trioxide induces human tumor cell apoptosis and G2 + M arrest whereas causes HPV16 DNA immortalized cervical epithelial cells G1 block]

OBJECTIVE

To investigate whether As2O3 induces tumor cell apoptosis and cell cycle arrest.

METHODS

DNA agarose gel electrophoresis, flowcytometry analysis, RT-PCR, and Western blot.

RESULTS

As2O3 induced G2 + M arrest of tumor cells such as GLC-82, MGC-803, SGC-7901, Eca109 and HeLa cells before inducing apoptosis and decreased c-myc gene expression, whereas caused G1 block of HPV16 DNA immortalized cervical epithelial HCE16/3 cells and did not affect c-myc expression.

CONCLUSIONS

As2O3 caused apoptosis was related with cell cycle arrest. However, the phase of arrest of tumor cells was different from the pre-tumor cell HCE16/3 cells, which could be related to the change of c-myc gene expression.

The 1.7 A crystal structure of human cell cycle checkpoint kinase Chk1: implications for Chk1 regulation

The checkpoint kinase Chk1 is an important mediator of cell cycle arrest following DNA damage. The 1.7 A resolution crystal structures of the human Chk1 kinase domain and its binary complex with an ATP analog has revealed an identical open kinase conformation. The secondary structure and side chain interactions stabilize the activation loop of Chk1 and enable kinase activity without phosphorylation of the catalytic domain. Molecular modeling of the interaction of a Cdc25C peptide with Chk1 has uncovered several conserved residues that are important for substrate selectivity. In addition, we found that the less conserved C-terminal region negatively impacts Chk1 kinase activity.

[Protection of hypertonic saline/mannitol to thymic cell apoptosis induced by endotoxin (LPS) in mice]

To observe the effect of HSM (hypertonic saline/mannitol) on thymic cell apoptosis induced by endotoxin (LPS) in mice, twenty-four mice were divided into three groups (8 mice/each group): 1. Control group, each mouse was intraperitonealy injected with normal saline; 2. LPS group, each mouse was intraperitonealy injected with LPS; 3. LPS + HSM group, each mouse was intraperitonealy injected with HSM before and after injection of LPS. The results showed that the percentage of apoptosis of HSM + LPS group was lower than that of LPS group (P < 0.01); the ladder of nucleosomal DNA fragments by agarose gel eletrophoresis of HSM group was not typical as compared with that of LPS group. It is suggested that HSM might protect the apoptosis of mouse thymic cell induced by LPS and may improve the immune function.

Xanthene-bridged cofacial bisporphyrins

The synthesis and characterization of cofacial bisporphyrins juxtaposed by xanthene-bridged pillars are presented. The one-pot preparation of the xanthene dialdehyde avoids the lengthy bridge synthesis accompanying other cofacial porphyrin systems, thus allowing for the facile preparation of homobimetallic zinc (10), copper (11), and nickel (12) complexes. The cofacial orientation of the two porphyrin macrocycles was confirmed by X-ray crystallography. Structural data are provided for bisporphyrins 10-12: 10 (C79H82N8OZn2), triclinic, space group P1, a = 11.2671(2) A, b = 14.9809(2) A, c = 20.4852(2) A, alpha = 101.6680(10) degrees, beta = 100.8890(10) degrees, gamma = 101.8060(10) degrees, Z = 2; 11 (C79H82N8OCu2), triclinic, space group P1, a = 11.21410(10) A, b = 14.9539(5) A, c = 20.6915(7) A, alpha = 101.810(2) degrees, beta = 101.044(2) degrees, gamma = 101.722(2) degrees, Z = 2; 12 (C79H82N8ONi2), monoclinic, space group C2/c, a = 24.1671(4) A, b = 10.669 A, c = 50.5080(9) A, beta = 99.553(2) degrees, Z = 8. Exciton interactions between the porphyrin rings are apparent in electronic spectra, consistent with the cofacial superstructure. The combination of structural and spectroscopic data provides a basis for the design of additional metal derivatives for the activation of dioxygen and other small molecules.

Changes in airway responsiveness and relative factors in asthma with remission at puberty

OBJECTIVE

To elucidate the airway responsiveness and its relative factors in asthma with natural remission at puberty.

METHOD

The airway responsiveness was evaluated by provocation of methacholine (PC20). Blood sIL-2R, IL-4 and IFN-gamma values in the cultural supernatant of mononuclear cells, eosinophil count, basophil count and basophil releasability were detected in 18 asthmatic cases with remission at puberty (group I), in 20 asthmatics without remission at puberty (group II), and in 30 healthy controls (group III).

RESULT

The mean value of PC20 in group I was significantly lower than that in group III (P < 0.01), but still higher than that in group II (P < 0.01). The blood sIL-2R, and eosinophil counts dropped almost to those of group III, significantly lower than those of group II. IL-4 in the culture supernatant of mononuclear cells was similar to group III, but significantly lower than that in group II. However IFN-gamma was also similar to group III, significantly higher than that of group II. The basophil count and positive rate of human basophil degranulation test stimulated by mannitol with hyper-osmolarity were still abnormal, significantly higher than those of group III, and the basophil level was significantly related to the airway responsiveness.

CONCLUSION

The asthmatics with remission at puberty have a certain degree of airway hyper-responsiveness that is related to the abnormality of basophil.

[Arsenic trioxide induced human esophageal cancer Ec109 cell apoptosis with downregulation of c-myc gene expression]

OBJECTIVE

To study effect of downregulation of c-myc gene expression with As2O3 on inducing Ec109 cell apoptosis.

METHODS

MTT reduction assay, flowcytometric analysis, DNA gel electrophoresis, Western blot and in situ cell death detection (TUNEL).

RESULTS

The viability of the cells treated with As2O3 was decreased. The cells treated with As2O3 showed a typical apoptotic morphology and hypodiploid peak before G1 phase. DNA of treated Ec109 cells appeared a ladder pattern characteristic of apoptosis. TUNEL detection analysis also revealed the DNA fragmentation and As2O3 decreased c-myc gene expression was observed.

CONCLUSIONS

As2O3 can induce Ec109 cell apoptosis with downregulation of c-myc gene expression.

[Effects of chincap therapy for early anterior crossbite]

OBJECTIVE

To analysis the effects of chincap therapy for early anterior crossbite and mandibular prognathism.

METHODS

136 patients anterior crossbite and mandibular prognathism aged from 3 to 14 years old at the start of treatment were treated with active chincap with bilateral force of 700 to 1000 gram. Every patient wore chin cap 12 to 14 hours daily, and most of those patients used removable appliances to open the crossbite of incisors. According to the age of patients, they were divided into four groups, C1 (3-5 years old), C2 (6-8 years old), C3 (9-11 years old) and C4 (12-14 years old). When the treatment ended after two years, we analyzed the models by measuring the length of maxillary on the models before and after treatment (U1 and U2 that's the distance between the tip of 1|1 and the distal plane of 6|6 or V|V and the overjet before and after treatment (L1 and L2). Then we calculated the obtained distance for the mandible related to the maxillary position X(X = (L2-L1)-(U2-U1)) and analyzed treating time and mandibular retreating speed in the four groups.

RESULTS

The obtained distance for the mandible related to the maxillary position in C1, C2, C3 and C4 groups were 3.27 +/- 0.99 mm, 4.62 +/- 1.33 mm, 4.43 +/- 1.28 mm and 2.63 +/- 0.92 mm respectively, and the treating time in four groups were 8.92 +/- 2.66 months, 10.47 +/- 2.21 months, 13.07 +/- 2.00 months, 20.50 +/- 3.96 months respectively. The retreating speed of the mandible related to the maxillary position in the four groups were 0.37 mm/month, 0.44 mm/month, 0.34 mm/month and 0.13 mm/month respectively. The effects of the treatment in C1, C2 and C3 groups (3-11 years old) were remarkable, especially in C1 group (3-5 years old).

CONCLUSION

The effects of chincap therapy for early anterior crossbite and mandibular prognathism were remarkable, especially for the very early crossbite patients.

Characterisation of two new gene cassettes, aadA5 and dfrA17

Escherichia coli INS33 was isolated from the urinary tract of an infected patient. It was resistant to ampicillin, chloramphenicol, spectinomycin, streptomycin, sulfafurazole, tetracycline and trimethoprim. PCR screening revealed the presence of a class 1 integron that harboured two new gene cassettes, designated dfrA17 and aadA5. The new dfrA17 cassette was 91% identical to the known dfrA7 cassette. The aadA5 cassette was 95% identical over the first 830 bp to aadA4, but lacked the IS26 element found at the 3' end of this truncated cassette. Cloning and expression of the cassette region demonstrated that dfrA17 conferred high level resistance to trimethoprim but aadA5 conferred resistance to spectinomycin but not to streptomycin.

PSM, a mediator of PDGF-BB-, IGF-I-, and insulin-stimulated mitogenesis

PSM/SH2-B has been described as a cellular partner of the FcepsilonRI receptor, insulin receptor (IR), insulin-like growth factor-I (IGF-I) receptor (IGF-IR), and nerve growth factor receptor (TrkA). A function has been proposed in neuronal differentiation and development but its role in other signaling pathways is still unclear. To further elucidate the physiologic role of PSM we have identified additional mitogenic receptor tyrosine kinases as putative PSM partners including platelet-derived growth factor (PDGF) receptor (PDGFR) beta, hepatocyte growth factor receptor (Met), and fibroblast growth factor receptor. We have mapped Y740 as a site of PDGFR beta that is involved in the association with PSM. We have further investigated the putative role of PSM in mitogenesis with three independent experimental strategies and found that all consistently suggested a role as a positive, stimulatory signaling adapter in normal NIH3T3 and baby hamster kidney fibroblasts. (1) PSM expression from cDNA using an ecdysone-regulated transient expression system stimulated PDGF-BB-, IGF-I-, and insulin- but not EGF-induced DNA synthesis in an ecdysone dose-responsive fashion; (2) Microinjection of the (dominant negative) PSM SH2 domain interfered with PDGF-BB- and insulin-induced DNA synthesis; and (3) A peptide mimetic of the PSM Pro-rich putative SH3 domain-binding region interfered with PDGF-BB-, IGF-I-, and insulin- but not with EGF-induced DNA synthesis in NIH3T3 fibroblasts. This experiment was based on cell-permeable fusion peptides with the Drosophila antennapedia homeodomain which effectively traverse the plasma membrane of cultured cells. These experimental strategies independently suggest that PSM functions as a positive, stimulatory, mitogenic signaling mediator in PDGF-BB, IGF-I, and insulin but not in EGF action. This function appears to involve the PSM SH2 domain as well as the Pro-rich putative SH3 domain binding region. Our findings support the model that PSM participates as an adapter in various mitogenic signaling mechanisms by linking an activated (receptor) phospho-tyrosine to the SH3 domain of an unknown cellular partner.