Tumor suppressor function of BCSC-1 in nasopharyngeal carcinoma

BCSC-1 is dramatically upregulated in CNE-2L2 human nasopharyngeal carcinoma cells with reduced malignancy (AS cells) and is proposed to be a candidate tumor suppressor gene. We therefore examined the effect of BCSC-1 expression on malignant behaviors of CNE-2L2 cells. Growth in vitro and tumorigenesis in nude mice of wild-type CNE-2L2 cells (W cells) were inhibited by ectopic BCSC-1, and those of AS cells were promoted by BCSC-1 suppression. The tumor suppressor function of BCSC-1 was further confirmed by a study showing that intratumor BCSC-1 injection caused growth suppression of the tumor from W cells inoculated in nude mice. Immunohistochemistry exhibited marked reduction of BCSC-1 expression in 11 of 39 human nasopharyngeal carcinoma specimens. Because BCSC-1 expression was as rich as that in normal cells in the rest of the carcinoma specimens and was poor in CNE-2L2 cells, HNE-1 human nasopharyngeal carcinoma cells with rich BCSC-1 expression were used as a control in the study. No effect of BCSC-1 transfection on growth of the cells was observed. The data suggest that BCSC-1 suppression might play roles in tumorigenesis of some nasopharyngeal carcinomas and that BCSC-1 might be a potential gene therapy target in nasopharyngeal carcinomas with poor BCSC-1 expression. Enhanced aggregation of cells together with increased E-cadherin and alpha-catenin expression and reduced Wnt signaling might be involved in the mechanisms of tumor suppressor function of BCSC-1.

Expression of IQGAP2 and its clinical significance in hepatocellular carcinoma

AIM: To investigate the expression of IQ motif containing GTPase activating protein 2 (IQGAP2) and its correlation with the clinicopathological parameters in hepatocellular carcinoma (HCC), and to reveal the potential mechanisms of IQGAP2 underlying human hepatocarcinogenesis.

METHODS: Western blot, immunofluorescence staining and immunohistochemical staining (IHC) were used to detect the expression and subcellular localization of IQGAP2 in 7 liver cancer and normal liver cell lines, as well as in 51 HCC tissue specimens. Meanwhile, the corresponding clinical data were analyzed retrospectively.

RESULTS: Only two liver cancer cell lines, HepG2 and Hep3B, expressed IQGAP2 at the protein level. In addition, immunofluorescence results revealed that IQGAP2 was localized in cytoplasm and nuclei. Apparent nucleolus and karyotheca staining was observed in HepG2 cells. Furthermore, histological validation of clinical samples showed that IQGAP2 expression was significantly down-regulated in tumor tissues (56.9%, 29/51). Meanwhile, the expression of IQGAP2 was associated with tumor size, AJCC staging and alpha-fetoprotein (AFP) expression level (P = 0.020; P = 0.017; P = 0.002). The immunohistochemical staining results from 38 HCC specimens showed that IQGAP2 was mainly localized at cytoplasm in the tumor and adjacent normal liver cells. In addition, partial cells had cell membrane and nuclear localization. However, definite association was not observed between IQGAP2 levels and tumor size, histological degree, AJCC staging or AFP expression status.

CONCLUSION: IQGAP2 expression is down-regulated in tumor tissues of HCC cases, and IQGAP2 may be a potential marker and tumor suppressor gene involved in HCC. These novel findings may provide a basis for the determination of mechanism(s) underlying human hepatocarcinogenesis.

Identification and functional characterization of an aggregation domain in long myosin light chain kinase

The functions of long smooth muscle myosin light chain kinase (L-MLCK), a molecule with multiple domains, are poorly understood. To examine the existence of further potentially functional domains in this molecule, we analyzed its amino acid sequence with a tango program and found a putative aggregation domain located at the 4Ig domain of the N-terminal extension. To verify its aggregation capability in vitro, expressible truncated L-MLCK variants driven by a cytomegalovirus promoter were transfected into cells. As anticipated, only the overexpression of the 4Ig fragment led to particle formation in Colon26 cells. These particles contained 4Ig polymers and actin. Analysis with detergents demonstrated that the particles shared features in common with aggregates. Thus, we conclude that the 4Ig domain has a potent aggregation ability. To further examine this aggregation domain in vivo, eight transgenic mouse lines expressing the 4Ig domain (4Ig lines) were generated. The results showed that the transgenic mice had typical aggregation in the thigh and diaphragm muscles. Histological examination showed that 7.70 +/- 1.86% of extensor digitorum longus myofibrils displayed aggregates with a 36.44% reduction in myofibril diameter, whereas 65.13 +/- 3.42% of diaphragm myofibrils displayed aggregates and the myofibril diameter was reduced by 43.08%. Electron microscopy examination suggested that the aggregates were deposited at the mitochondria, resulting in structural impairment. As a consequence, the oxygen consumption of mitochondria in the affected muscles was also reduced. Macrophenotypic analysis showed the presence of muscular degeneration characterized by a reduction in force development, faster fatigue, decreased myofibril diameters, and structural alterations. In summary, our study revealed the existence of a novel aggregation domain in L-MLCK and provided a direct link between L-MLCK and aggregation. The possible significance and mechanism underlying the aggregation-based pathological processes mediated by L-MLCK are also discussed.

Immune response induced by spike protein from transmissible gastroenteritis coronavirus expressed in mouse mammary cells

The present study is undertaken to investigate the immune response that was induced by the recombinant spike (S) protein from swine-transmissible gastroenteritis virus (TGEV) expressed in mouse mammary cells. A mammary-specific expression vector pEBS containing the full-length cDNA of S gene was constructed and expressed in the mouse mammary cells (EMT6). The recombinant S protein from culture supernatant of transgenic EMT6 was harvested and immunized BALB/c mice. The results demonstrated recombinant S protein was expressed at high levels in mammary cells by Western blotting and enzyme-linked immunosorbent assay (ELISA) detection. The antibody titer in BALB/c mice following immunization with recombinant S protein was detectable after the first immunization. Maximum titers of antibody (8.86 ± 0.19 ng/ml of serum) were attained after the second immunization. In conclusion, the recombinant S protein expressed in mammary cells was able to elicit substantial immunological response against TGEV. This lays the basis for using mammary gland bioreactor generating edible vaccine.

Immortalization of bovine germ line stem cells by c-myc and hTERT

The limited life span of bovine germ line stem cells in vitro is one of the obstacles to spermatogenesis analysis, genetic manipulation and generating transgenic animal. The aim of this study is to establish immortalized bovine germ line stem cells by c-myc or hTERT. We constructed pEMY and pETE expression vectors and transfected germ line cells from 5-month-old bovine. After G418 screening, four types of positive clones were obtained. The results showed that they expressed exogenous genes c-myc or hTERT at mRNA and protein level by RT-PCR and Western blotting detection. Presumable cell lines GM7, GT3, GMT5 all expressed germ-line-stem-cell-specific makers by immunocytochemical analysis, such as c-kit, Oct-4 and GFRalpha-1. The putative cell lines also had higher capacity of proliferation than freshly isolated bovine spermatogonial stem cells. So we can conclude that exogenous genes c-myc or hTERT have integrated into the genome of bovine germ cells and upregulated the expression of telomerase.

[Influence of glutamate and NMDA-receptor antagonist MK-801 on the electric activities of pain-excitation neurons in the nucleus accumbens of rats]

The experiment explored the influence of glutamic acid (Glu) and the NMDA-receptor antagonist dizocilpine maleate (MK-801) on the pain-evoked responses of pain-excitation neurons (PEN) in the nucleus accumbens (NAc) of rats. The trains of electric impulses applied to the sciatic nerve were used as noxious stimulation. The discharges of PEN in NAc were recorded by glass microelectrode. We observed the influence of intracerebroventricular (icv) injection of Glu and microinjection of MK-801 into the NAc on the noxious stimulation-evoked activities of PEN in NAc. The results showed that the noxious stimulation potentiated the electric activities of PEN in NAc. Intracerebroventricular injection of Glu (10 nmol/10 microl) increased the frequency of the discharge of PEN evoked by the noxious stimulation in NAc, the Glu-induced response was blocked by the injection of MK-801 (1.0 nmol/0.5 microl) into NAc. MK-801 partly inhibited the response of PEN upon the noxious stimulation. It is therefore suggested that the facilitatory effect of Glu on PEN response in NAc to the noxious stimulation is mediated by NMDA receptors, and that Glu and NMDA receptors are involved in the modulation of nociceptive information transmission in the NAc.

Detection of tumor-associated biomarkers in precancerous lesions of esophagus

AIM: To investigate the expressions of annexin I, Grp94, p53, Ki-67 in esophageal squamous cell carcinoma (ESCC) and precancerous lesion, in order to provide valuable clues for early diagnosis.

METHODS: Seventy-two specimens were collected, including dysplasia, in situ carcinoma, early ESCC, ESCC and lymph metastatic carcinoma. The expression of annexin I, Grp94, mutant p53 and ki-67 were detected using immunohistochemical staining (IHC).

RESULTS: Compared with the normal esophageal epithelia, the expressions of annexin I, Grp94, mutant p53 and ki-67 were abnormal in precancerous lesions. Loss of annexin I (68.3%), positive expression of p53 (67.6%) and ki-67 (71.1%) were observed in low grade lesions (P < 0.01), and Grp94 expression was increased significantly (62.0%) in early invasive cancer (P < 0.01).

CONCLUSION: Annexin I, mutant p53 and ki-67 may be the biomarkers of early ESCC, and Grp94 may be an important biomarker of progressive ESCC.

[The relation between amygdaloid nucleus in rats and pain modulation]

AIM

To research the influence of noxious stimuli on the electric activities of pain-related neurons in several subnuclei of Amygdaloid Nucleus in rats.

METHODS

Trains of the electric impulses applied to the sciatic nerve were used as noxious stimuli. The discharges of neurons were channeled off by glass microelectrode.

RESULTS

Pain-related neurons existed in several subnuclei of Amygdaloid Nucleus. When the noxious stimuli were administered the frequency of discharges of pain-excited neurons (PEN) was increased while the frequency of pain-inhibited neurons (PIN) was decreased to the lowest level. The electric activities of PEN and PIN were matched with each other. Intraperitoneal injection of morphine (10 mg/kg) antagonized the effects of noxious stimuli on the pain-related neurons.

CONCLUSION

Several subnuclei of Amygdaloid Nucleus play an essential role in perceiving, integrating and transmitting the pain impulses. They are a part of the central nervous system in which pain information is controlled and managed.