The Biological and Molecular Function of LINC00665 in Human Cancers.

Long non-coding RNAs (lncRNAs) are more than 200 nucleotides in length and are implicated in the development of human cancers, without protein-coding function. Mounting evidence indicates that cancer initiation and progression are triggered by lncRNA dysregulation. Recently, a growing number of studies have found that LINC00665, a long intergenic non-protein coding RNA, may be associated with various cancers, including gastrointestinal tumors, gynecological tumors, and respiratory neoplasms. LINC00665 was reported to be significantly dysregulated in cancers and has an important clinical association. It participates in cell proliferation, migration, invasion, and apoptosis through different biological pathways. In this review, we summarize the current findings on LINC00665, including its biological roles and molecular mechanisms in various cancers. LINC00665 may be a potential prognostic biomarker and novel therapeutic target for cancers.

Estrogen augmented visceral pain and colonic neuron modulation in a double-hit model of prenatal and adult stress.

BACKGROUND: Chronic stress during pregnancy may increase visceral hyperalgesia of offspring in a sex-dependent way. Combining adult stress in offspring will increase this sensitivity. Based on the evidence implicating estrogen in exacerbating visceral hypersensitivity in female rodents in preclinical models, we predicted that chronic prenatal stress (CPS) + chronic adult stress (CAS) will maximize visceral hyperalgesia; and that estrogen plays an important role in colonic hyperalgesia. AIM: The aim was to illuminate the role of estrogen in colonic hyperalgesia and its underlying mechanisms. METHODS: We established a CPS plus CAS rodent model in which the balloon was used to distend the colorectum. The single-fiber recording in vivo and patch clamp experiments in vitro were used to monitor the colonic neuron's activity. The reverse transcription-polymerase chain reaction, western blot, and immunofluorescence were used to study the effects of CPS and CAS on colon primary afferent sensitivity. We used ovariectomy and letrozole to reduce estrogen levels of female rats respectively in order to assess the role of estrogen in female-specific enhanced primary afferent sensitization. RESULTS: Spontaneous activity and single fiber activity were significantly greater in females than in males. The enhanced sensitization in female rats mainly came from low-threshold neurons. CPS significantly increased single-unit afferent fiber activity in L6-S2 dorsal roots in response. Activity was further enhanced by CAS. In addition, the excitability of colon-projecting dorsal root ganglion (DRG) neurons increased in CPS + CAS rats and was associated with a decrease in transient A-type K+ currents. Compared with ovariectomy, treatment with the aromatase inhibitor letrozole significantly reduced estrogen levels in female rats, confirming the gender difference. Moreover, mice treated with letrozole had decreased colonic DRG neuron excitability. The intrathecal infusion of estrogen increased brain-derived neurotrophic factor (BDNF) protein levels and contributed to the response to visceral pain. Western blotting showed that nerve growth factor protein was upregulated in CPS + CAS mice. CONCLUSION: This study adds to the evidence that estrogen-dependent sensitization of primary afferent colon neurons is involved in the development of chronic stress-induced visceral hypersensitivity in female rats.

SP600125 blocks the proteolysis of cytoskeletal proteins in apoptosis induced by gas signaling molecule (NO) via decreasing the activation of caspase-3 in rabbit chondrocytes.

NO plays a key role in the pathological mechanisms of articular diseases. As cytoskeletal proteins are responsible for the polymerization, stabilization, and dynamics of the cytoskeleton network, we investigated whether cytoskeletal proteins are the intracellular pathological targets of NO. We aimed at clarifying whether the cytoskeleton perturbations involved in apoptosis are induced in rabbit articular chondrocytes by NO, which can be liberated by sodium nitroprusside (SNP) treatment. The first passage rabbit articular chondrocytes were cultured as monolayer for the experiments, and the effects of NO were tested in the presence of JNK-specific inhibitor, SP600125. SNP treatment of cultured chondrocytes caused significant apoptosis in a concentration-dependent manner (time and dose), as evaluated by TUNEL assay and Annexin V flow cytometry, while the apoptosis was reduced by the SP600125 addition 30 min before SNP treatment. Besides, SP600125 decreased significantly the protein expression of total caspase-3 and the intracellular gene expression of caspase-3, measured by Western blot analysis and PCR. SP600125 also increased the cytoskeletal protein expressions. These results suggested that JNK pathway plays a critical role in the NO-induced chondrocyte apoptosis, and SP600125 treatment blocks the dissolution of the cytoskeletal proteins via activation of caspase-3 pathways.

CaMKII-mediated Beclin 1 phosphorylation regulates autophagy that promotes degradation of Id and neuroblastoma cell differentiation.

Autophagy is a degradative pathway that delivers cellular components to the lysosome for degradation. The role of autophagy in cell differentiation is poorly understood. Here we show that CaMKII can directly phosphorylate Beclin 1 at Ser90 to promote K63-linked ubiquitination of Beclin 1 and activation of autophagy. Meanwhile, CaMKII can also promote K63-linked ubiquitination of inhibitor of differentiation 1/2 (Id-1/2) by catalyzing phosphorylation of Id proteins and recruiting TRAF-6. Ubiquitinated Id-1/Id-2 can then bind to p62 and be transported to autolysosomes for degradation. Id degradation promotes the differentiation of neuroblastoma cells and reduces the proportion of stem-like cells. Our study proposes a mechanism by which autophagic degradation of Id proteins can regulate cell differentiation. This suggests that targeting of CaMKII and the regulation of autophagic degradation of Id may be an effective therapeutic strategy to induce cell differentiation in neuroblastoma.

[Expression of Proteus mirabilis polyphosphate kinase and preparation of its polyclonal antibodies].

OBJECTIVE: To express and purify polyphosphate kinase (PPK) from Proteus mirabilis and prepare the polyclonal antibody against PPK. METHODS: The antigenicity and hydrophobicity of PPK were analyzed using software. The N-terminal conservative sequence containing 309 amino acids was selected as the target peptide, and its corresponding gene sequence with modification based on prokaryotic cells-preferred codon was synthesized and inserted into plasmid pET28b(+). The constructed recombinant plasmid was transformed into Escherichia coli BL21 (DE3) and induced with IPTG. The expressed fusion protein was purified using Ni-affinity chromatography. The purified protein was injected along with adjuvant in rabbits to prepare the polyclonal antibodies against PPK. RESULTS AND CONCLUSION: PPK fusion protein expressed by E. coli was purified successfully using Ni-affinity chromatography. ELISA result demonstrated that the harvested rabbit anti-sera against PPK had a high titer of 1:512 000, and Western blotting showed a good specificity of the antibody, which can be used further study of the role of PPK in the pathogenesis of Proteus mirabilis infection.

ATM-mediated PTEN phosphorylation promotes PTEN nuclear translocation and autophagy in response to DNA-damaging agents in cancer cells.

PTEN (phosphatase and tensin homolog), a tumor suppressor frequently mutated in human cancer, has various cytoplasmic and nuclear functions. PTEN translocates to the nucleus from the cytoplasm in response to oxidative stress. However, the mechanism and function of the translocation are not completely understood. In this study, topotecan (TPT), a topoisomerase I inhibitor, and cisplatin (CDDP) were employed to induce DNA damage. The results indicate that TPT or CDDP activates ATM (ATM serine/threonine kinase), which phosphorylates PTEN at serine 113 and further regulates PTEN nuclear translocation in A549 and HeLa cells. After nuclear translocation, PTEN induces autophagy, in association with the activation of the p-JUN-SESN2/AMPK pathway, in response to TPT. These results identify PTEN phosphorylation by ATM as essential for PTEN nuclear translocation and the subsequent induction of autophagy in response to DNA damage.

[Role of JNK signaling pathway in chondrocyte apoptosis induced by nitric oxide].

OBJECTIVE: To study the role of c-jun N-terminal kinase (JNK) signaling pathway in chondrocyte apoptosis induced by nitric oxide (NO) using NO donor sodium nitroprusside (SNP) and JNK inhibitor SP600125. METHODS: Articular chondrocytes were separated from New Zealand rabbits aged 3 weeks by mechanical digestion and enzyme digestion and identified by toluidine blue staining, and then the chondrocytes were treated with SNP and SP600125 for 24 h. The cell apoptosis was evaluated by Annexin V-fluorescein isothiocyanate (FITC)/propidium iodide (PI) flow cytometry and terminal deoxynucleotidyl transferase (TdT)-mediated dUTP-biotin nick end labeling (TUNEL), and the expression levels of nuclear factor-kappa B (NF-κB) p65 and p53 were measured by western blot. RESULTS: Compared with those in control group, the early apoptotic rate of SNP-treated chondrocytes increased as the concentration of SNProse, exhibiting a concentration dependency (P < 0.05), and the expression levels of NF-κB p65 and p53 also increased (P < 0.05); JNK inhibitor SP600125 inhibited these increases (P < 0.05). CONCLUSION: JNK signaling pathway plays an important role in NO-induced chondrocyte apoptosis. JNK inhibitor SP600125 can reduce NO-induced apoptosis and expression of NF-κB p65 and p53 in articular chondrocytes of rabbits in a concentration-dependent manner.

Histopathology of chondronecrosis development in knee articular cartilage in a rat model of Kashin-Beck disease using T-2 toxin and selenium deficiency conditions.

The objective of this study is to observe pathogenic lesions of joint cartilages in rats fed with T-2 toxin under a selenium deficiency nutrition status in order to determine possible etiological factors causing Kashin-Beck disease (KBD). Sprague-Dawley rats were fed selenium-deficient or control diets for 4 weeks prior to their being exposed to T-2 toxin. Six dietary groups were formed and studied 4 weeks later, i.e., controls, selenium-deficient, low T-2 toxin, high T-2 toxin, selenium-deficient diet plus low T-2 toxin, and selenium-deficient diet plus high T-2 toxin. Selenium deficiencies were confirmed by the determination of glutathione peroxidase activity and selenium levels in serum. The morphology and pathology (chondronecrosis) of knee joint cartilage of experimental rats were observed using light microscopy and the expression of proteoglycans was determined by histochemical staining. Chondronecrosis in deep zone of articular cartilage of knee joints was seen in both the low and high T-2 toxin plus selenium-deficient diet groups, these chondronecrotic lesions being very similar to chondronecrosis observed in human KBD. However, the chondronecrosis observed in the rat epiphyseal growth plates of animals treated with T-2 toxin alone or T-2 toxin plus selenium-deficient diets were not similar to that found in human KBD. Our results indicate that the rat can be used as a suitable animal model for studying etiological factors contributing to the pathogenesis (chondronecrosis) observed in human KBD. However, those changes seen in epiphyseal growth plate differ from those seen in human KBD probably because of the absence of growth plate closure in the rat.

Sodium valproate induces mitochondria-dependent apoptosis in human hepatoblastoma cells.

BACKGROUND: Sodium valproate inhibits proliferation in neuroblastoma and glioma cells, and inhibits proliferation and induces apoptosis in hepatoblastoma cells. Information describing the molecular pathways of the antitumor effects of sodium valproate is limited; therefore, we explored the mechanisms of action of sodium valproate in the human hepatoblastoma cell line, HepG2. METHODS: The effects of sodium valproate on the proliferation of HepG2 cells were evaluated by the Walsh-schema transform and colony formation assays. Sodium valproate-induced apoptosis in HepG2 cells was investigated with fluorescence microscopy to detect morphological changes; by flow cytometry to calculate DNA ploidy and apoptotic cell percentages; with Western blotting analyses to determine c-Jun N-terminal kinases (JNK), p-JNK, Bcl-2, Bax, and caspase-3 and -9 protein expression levels; and using JC-1 fluorescence microscopy to detect the membrane potential of mitochondria. Statistical analyses were performed using one-way analysis of variance by SPSS 13.0 software. RESULTS: Our results indicated that sodium valproate treatment inhibited the proliferation of HepG2 cells in a dose-dependent manner. Sodium valproate induced apoptosis in HepG2 cells as it: caused morphologic changes associated with apoptosis, including condensed and fragmented chromatin; increased the percentage of hypodiploid cells in a dose-dependent manner; increased the percentage of annexin V-positive/propidium iodide-negative cells from 9.52% to 74.87%; decreased JNK and increased phosphate-JNK protein expression levels; reduced the membrane potential of mitochondria; decreased the ratio of Bcl-2/Bax; and activated caspases-3 and -9. CONCLUSION: Sodium valproate inhibited the proliferation of HepG2 cells, triggered mitochondria-dependent HepG2 cell apoptosis and activated JNK.

Expressions of nucleoside diphosphate kinase (nm23) in tumor tissues are related with metastasis and length of survival of patients with hepatocellular carcinoma.

OBJECTIVE: To evaluate the relationship of expressions of nucleoside diphosphate kinase (nm23) and proliferating cell nuclear antigen (PCNA), as well as apoptosis, with the prognosis of HCC patients by analyzing their pathological and clinical data. METHODS: The expressions of nm23 and PCNA were analyzed by immunohistochemistry and the apoptotic phenomena were detected by TUNEL technique in the liver samples from 43 HCC tissues, 39 para-neoplastic tissues, and 10 normal tissues. The mean apoptosis index (AI) and proliferative index (PI) in individual sample were calculated. RESULTS: As shown by the detection, 32.6% of carcinomas had negative nm23 signal in tumor tissues, whereas all para-neoplastic and normal tissues had positive nm23. The AI in nm23 positive HCC was significantly higher than that in nm23 negative one, with statistical difference (P<0.05). Furthermore, the expressions of nm23, and the values of AI and PI were contrastively analyzed with some main pathological and clinical data of HCC. It revealed that HCC with extrahepatic metastasis showed remarkable correlation with the negative nm23 (P=0.013) and higher PI values of HCC (P=0.015). The disease-free survival in HCC patients with negative nm23 expression was significantly poorer than that in patients with positive nm23 expression. CONCLUSIONS: These data suggest that expressions of nm23 protein in tumor tissues are correlated with occurrences of metastasis and length of survival of the HCC patients, which may be an indicator for their prognosis.

Evaluation of liposomal curcumin cytochrome p450 metabolism.

BACKGROUND: Curcumin (diferuloylmethane) is a commonly used spice and nutritional supplement that has demonstrated potential anti-tumor and anti-inflammatory activity. There is limited information regarding curcumin metabolism and the potential for drug-drug interactions. The objective of this study was to characterize the hepatic metabolism of synthetic curcumin used in the liposomal curcumin formulation. MATERIALS AND METHODS: High-throughput cytochrome P450 (CYP450) metabolism inhibition assays were conducted in vitro evaluating CYP450 3A4, 2C8, 2C9, and 2D6. An ex vivo model of cryopreserved human hepatocytes was used to evaluate the CYP450 metabolism induction potential of curcumin for CYP P450 3A4, 2C8/2C9, and 2D6. RESULTS: In the in vitro CYP450 inhibition studies, curcumin at any concentration did not inhibit CYP450 3A4 or CYP450 2D6 activity. At a curcumin concentration of 58.3 microM, 10.5% and 22.5% inhibition of CYP450 2C9 and CYP450 2C8 activity, respectively, was observed. In the ex vivo hepatocyte inductions studies, minimal to no induction of CYP450 3A4, CYP450 2C8/2C9 or CYP450 2D6 was observed. Rifampicin did not induce the metabolism of curcumin and curcumin did not induce its own metabolism. CONCLUSION: There is low potential for CYP450 mediated drug interactions at physiologic serum concentrations of liposomal curcumin. Based on preliminary data, liposomal curcumin will not interact with other chemotherapy agents that are metabolized and/or eliminated via the primary drug metabolizing CYP450 pathways.

Effects of moniliformin and selenium on human articular cartilage metabolism and their potential relationships to the pathogenesis of Kashin-Beck disease.

OBJECTIVE: To investigate the effects of mycotoxin moniliformin (MON) on the metabolism of aggrecan and type II collagen in human chondrocytes in vitro and the relationship between MON and Kashin-Beck disease (KBD). METHODS: Human chondrocytes were isolated and cultured on bone matrix gelatin to form an artificial cartilage model in vitro with or without MON toxin. Cell viability was determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The expression of aggrecan and type II collagen in the cartilage was determined using immunocytochemical staining. RESULTS: MON toxin inhibited chondrocyte viability in dose-dependent and time-dependent manners. MON reduced aggrecan and type II collagen syntheses in the tissue-engineered cartilage. MON also increased the expression of matrix metalloproteinase-1 (MMP-1), MMP-13, BC4 epitopes, and CD44 in cartilages. However, the expression of 3B3(-) epitopes in cartilages was inhibited by MON. Selenium partially alleviated the damage of aggrecan induced by MON toxin. CONCLUSION: MON toxin promoted the catabolism of aggrecan and type II collagen in human chondrocytes.

[Effect of Tanshinone II A on expression of EGF and EGFR in hepatocellular carcinoma cell line SMMC-7721].

OBJECTIVE: To observe the effect of Tanshinone II A on the expression of epidermal growth facter (EGF) and epidermal growth facter recepter (EGFR) in human hepatocellular carcinoma cell line SMMC-7721. METHODS: The human hepatocellular carcinoma SMMC-7721 cells cultured in vitro was treated with different concentrations of Tanshinone II A. The proliferation of the cells was measured by MTT assay, and the apoptosis of the cells was investigated by flow cytometry and cytochemical staining with Hoechst 33342. The expression of EGF and EGFR was detected by immunocytochemistry method. The levels of EGF in medium were measured by radioimmunoassay. RESULT: Tanshinone II A inhibited the growth of SMMC-7721 cells remarkably in a dose-dependent manner. The inhibitory rate reached the peak (72.5%) after 0.5 microg/ml Tanshinone II A was used for 48 h, which was significantly higher than that in the controls (P<0.05). FCM analysis showed that when SMMC-7721 cells were treated with 0.5 microg/ml Tanshinone II A, the apoptosis rates for 24 h, 48 h and 72 h were (4.06+/-0.27)%, (7.58+/-0.56)% and (5.23+/-0.13)%, respectively which were markedly higher than those in the controls (all P<0.01). SMMC-7721 cell apoptosis with cell shrinkage, nuclear chromatin concentration and fragmentation as well as the formation of apoptotic bodies were observed by cytochemical staining when treated with Tanshinone II A. The immunocytochemistry showed that the expressions of EGF and EGFR were down regulated while the concentration of Tanshinone II A was increasing. The high expression rates for EGF and EGFR were 10%, 20%, respectively, and the gray scale was 181.52+/-1.63, 179.37+/-1.59, which were markedly higher than those in the controls (all P<0.05). The levels of EGF in medium measured by radioimmunoassay were decreased significantly after Tanshinone II A treatment. CONCLUSION: Tanshinone II A can inhibit cell proliferation and induce apoptosis in hepatocellular carcinoma cell line SMMC-7721, which may be related to the down-regulation of EGF and EGFR protein expression.

Over-expression of nm23-H1 in HeLa cells provides cells with higher resistance to oxidative stress possibly due to raising intracellular p53 and GPX1.

AIM: To determine whether the antitumor factor nm23 is related with antioxidation. METHODS: Full-length human nm23-H1 was cloned into a mammalianexpressing vector and transiently introduced into HeLa cells. RESULTS: A remarkably low level of reactive oxygen species (ROS) was detected in the cells overexpressing nm23-H1. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide and trypan blue assays found that the cells transfected with a nm23- H1-expressing plasmid had higher viability and stronger resistance to oxidative stress. Immunoprecipitation tests revealed that endogenous nm23-H1 formed a protein complex with p53. Furthermore, the intracellular levels of p53 and p53- regulated gene GPX1 were obviously increased in the cells overexpressing nm23- H1. The downregulation of p53 in the cells overexpressing nm23-H1 resulted in a higher cellular ROS level and lower cell viability. CONCLUSION: The findings suggest that nm23-H1 may act as a cellular protector against oxidative stress, possibly triggering the p53-related antioxidative pathway.

T-2 toxin-induced apoptosis involving Fas, p53, Bcl-xL, Bcl-2, Bax and caspase-3 signaling pathways in human chondrocytes.

OBJECTIVE: To investigate the effects of T-2 toxin on expressions of Fas, p53, Bcl-xL, Bcl-2, Bax and caspase-3 on human chondrocytes. METHODS: Human chondrocytes were treated with T-2 toxin (1-20 ng/ml) for 5 d. Fas, p53 and other apoptosis-related proteins such as Bax, Bcl-2, Bcl-xL, caspase-3 were determined by Western blot analysis and their mRNA expressions were determined by reverse transcriptase-polymerase chain reaction (RT-PCR). RESULTS: Increases in Fas, p53 and the pro-apoptotic factor Bax protein and mRNA expressions and a decrease of the anti-apoptotic factor Bcl-xL were observed in a dose-dependent manner after exposures to 1-20 ng/ml T-2 toxin, while the expression of the anti-apoptotic factor Bcl-2 was unchanged. Meanwhile, T-2 toxin could also up-regulate the expressions of both pro-caspase-3 and caspase-3 in a dose-dependent manner. CONCLUSION: These data suggest a possible underlying molecular mechanism for T-2 toxin to induce the apoptosis signaling pathway in human chondrocytes by regulation of apoptosis-related proteins.

Promotion of the articular cartilage proteoglycan degradation by T-2 toxin and selenium protective effect.

OBJECTIVE: To identify the relationship between T-2 toxin and Kashin-Beck disease (KBD), the effects of T-2 toxin on aggrecan metabolism in human chondrocytes and cartilage were investigated in vitro. METHODS: Chondrocytes were isolated from human articular cartilage and cultured in vitro. Hyaluronic acid (HA), soluble CD44 (sCD44), IL-1beta and TNF-alpha levels in supernatants were measured by enzyme-linked immunosorbent assay (ELISA). CD44 content in chondrocyte membrane was determined by flow cytometry (FCM). CD44, hyaluronic acid synthetase-2 (HAS-2) and aggrecanases mRNA levels in chondrocytes were determined using reverse transcription polymerase chain reaction (RT-PCR). Immunocytochemical method was used to investigate expressions of BC-13, 3-B-3(-) and 2-B-6 epitopes in the cartilage reconstructed in vitro. RESULTS: T-2 toxin inhibited CD44, HAS-2, and aggrecan mRNA expressions, but promoted aggrecanase-2 mRNA expression. Meanwhile, CD44 expression was found to be the lowest in the chondrocytes cultured with T-2 toxin and the highest in control plus selenium group. In addition, ELISA results indicated that there were higher sCD44, IL-1beta and TNF-alpha levels in T-2 toxin group. Similarly, higher HA levels were also observed in T-2 toxin group using radioimmunoprecipitation assay (RIPA). Furthermore, using monoclonal antibodies BC-13, 3-B-3 and 2-B-6, strong positive immunostaining was found in the reconstructed cartilage cultured with T-2 toxin, whereas no positive staining or very weak staining was observed in the cartilage cultured without T-2 toxin. Selenium could partly inhibit the effects of T-2 toxin above. CONCLUSION: T-2 toxin could inhibit aggrecan synthesis, promote aggrecanases and pro-inflammatory cytokines production, and consequently induce aggrecan degradation in chondrocytes. These will perturb metabolism balance between aggrecan synthesis and degradation in cartilage, inducing aggrecan loss in the end, which may be the initiation of the cartilage degradation.

[Effect of NO and Fas pathway on T-2 induced apoptosis in chondrocytes].

OBJECTIVE: To investigate the relationship of T-2 toxin-induced chondrocytes apoptosis with nitric oxide(NO) and Fas apoptosis pathway. METHODS: Human chondrocytes cultured in vitro were treated with different concentrations of T-2 toxin at different time (1-5 d). Cell viability of the treated cells was measured by MTT assay. Apoptotic ultrostructural changes of the treated cells were observed with electron microscopy. Biological changes of apoptosis were detected by annexin V/PI Flow cytometer (FCM). The levels of NO in culture media were detected by colorimetric method of Griess assay. Nitric oxide synthase (iNOS) and Fas protein were measured by Western blot. RESULTS: In this study the results shown the dose-dependent and time-dependent effects of T-2 toxin, within a range of concentration (1-2000 ng/mL) and a period of time (1-5 d), on the T-2 toxin-treated chondrocytes. Apoptotic body was found in T-2 toxin-treated chondrocytes by electron microscopy. Early-stage apoptosis rate and late-stage apoptosis rate were both increased in T-2 toxin-treated cells when compared with non-treated cells in a dose-dependent manner. The levels of NO in T-2 toxin-treated culture media were higher than that of normal control. Over-expressions of iNOS and Fas protein were detected in T-2 toxin-treated cells. T-2 toxin-induced apoptosis was noted to be significtnly correlated with the level of NO production and the levels of iNOS and Fas protein expression. CONCLUSION: T-2 toxin can enhance NO production and upregulate the expression of iNOS and Fas protein. Both NO and Fas signaling pathway are involved in T-2 toxin-induced apoptosis.

[Mechanism of chondrocyte apoptosis in Kashin-Beck disease and primary osteoarthritis: a comparative study].

OBJECTIVE: To investigate chondrocyte apoptosis and the expressions of Bcl-2, Bax, Fas and iNOS in the articular cartilage between Kashin-Beck disease (KBD) and primary osteoarthritis (OA) and explore the difference in pathogenesis between the two diseases. METHODS: The articular cartilage specimens were collected from 15 normal human subjects, 15 adult patients with KBD and 15 with OA. Chondrocyte apoptosis was detected by TUNEL method, and the expressions of Bcl-2, Bax, Fas and iNOS in articular cartilage were examined with B-SA immunohistochemistry. RESULTS: The percentages of apoptotic chondrocytes positive for TUNEL staining in the articular cartilage were significantly higher in patients with KBD and OA than in normal control subjects (F=20.90-53.16, df=42, P<0.01), and the erosive areas of the articular cartilage contained greater percentage of apoptotic chondrocytes than the non-erosive areas in the same patient with KBD (t=4.154, df=28, P<0.01) or OA (t=6.004, df=28, P<0.01). No significant difference was noted in the positive apoptotic chondrocytes between KBD and OA (t=1.329-1.362, df=28, P>0.05). The percentage of chondrocytes positive for Bcl-2, Bax, Fas and iNOS were significantly higher in KBD and OA patients than in the control subjects (F=25.46-215.31, df=42, P<0.01), and significant differences were observed in Bcl-2, Bax, Fas and iNOS expressions between the erosed areas and non-erosed areas in articular cartilage in patients with KBD (t=2.608-7.77, df=28, P<0.05) and OA (t=2.278-5.413, df=28, P<0.05), but their expressions showed no significant difference between the two diseases (t=0.284-1.590, df=28, P>0.05). CONCLUSION: There was no significant difference in apoptotic chondrocytes and Bcl-2, Bax, Fas and iNOS expressions in the cartilage between adult patients with KBD and OA.

Spinal glial glutamate transporters downregulate in rats with taxol-induced hyperalgesia.

Changes in the expression of glial glutamate transporters (GLAST and GLT-1) were examined in the spinal cord of rats with chemotherapy (taxol)-induced mechanical hyperalgesia. Immunohistochemical studies show that the expression of both GLAST and GLT-1 in the L4-L5 spinal dorsal horn is decreased by 24% (P<0.001) and 23% (P<0.001), respectively, in rats with taxol-induced hyperalgesia as compared with those in control rats. These changes were further confirmed using an enzyme-linked immunosorbent assay that confirmed downregulation of GLAST by 36% (P<0.05) and GLT-1 by 18% (P<0.05) in the L4-L5 spinal cord of taxol-treated rats. These data indicate that downregulation of glutamate transporters may contribute to the development of hyperalgesia induced by taxol and suggest that glutamate transporters may be a new target for treatment of pain.