QUALITATIVE STUDY OF SIALOMUCINS CHANGES DURING N－METHYL－N－NITROSOUREA－INDUCED C OLONIC CARCINOGENESIS IN MICE

ＱＵＡＬＩＴＡＴＩＶＥＳＴＵＤＹＯＦＳＩＡＬＯＭＵＣＩＮＳＣＨＡＮＧＥＳＤＵＲＩＮＧＮ－ＭＥＴＨＹＬ－Ｎ－ＮＩＴＲＯＳＯＵＲＥＡ－ＩＮＤＵＣＥＤＣＯＬＯＮＩＣＣＡＲＣＩＮＯＧＥＮＥＳＩＳＩＮＭＩＣＥＷａｎｇＱｉａｎｇ王强；ＷａｎｇＹｕａｎｈｅ王元和；...     

CLINICOPATHOLOGIC FEATURES AND DIAGNOSISOF COMBINED HEPATOCELLULAR ANDCHOLANGIOCARCINOMA

ＣＬＩＮＩＣＯＰＡＴＨＯＬＯＧＩＣＦＥＡＴＵＲＥＳＡＮＤＤＩＡＧＮＯＳＩＳＯＦＣＯＭＢＩＮＥＤＨＥＰＡＴＯＣＥＬＬＵＬＡＲＡＮＤＣＨＯＬＡＮＧＩＯＣＡＲＣＩＮＯＭＡＬｕＪｉａｎｐｉｎｇ路建平；ＣａｉＷｅｉｍｉｎ蔡为民；ＨａｙａｓｈｉＫｅｉｋｉ１林肇辉...     

ISOLATION AND CHARACTERIZATION OF AN ADRIAMYCIN－RESISTANT SUBLINE OF THE HUMAN GASTRIC ADENOCARCINOMA CELLLINE

ＩＳＯＬＡＴＩＯＮＡＮＤＣＨＡＲＡＣＴＥＲＩＺＡＴＩＯＮＯＦＡＮＡＤＲＩＡＭＹＣＩＮ－ＲＥＳＩＳＴＡＮＴＳＵＢＬＩＮＥＯＦＴＨＥＨＵＭＡＮＧＡＳＴＲＩＣＡＤＥＮＯＣＡＲＣＩＮＯＭＡＣＥＬＬＬＩＮＥＷａｎｇＹａｎｐｉｎｇ；王艳萍；ＸｕＧａｎｇ；徐刚（Ｉ...     

Special Reports and Review ONCOGENES AND CELL IMMUNOGENITY：v－H－ras SUPPRESSING MHC CLASS I EXPRESSION IN MOUSE FIBROBLAST

ＳｐｅｃｉａｌＲｅｐｏｒｔｓａｎｄＲｅｖｉｅｗＯＮＣＯＧＥＮＥＳＡＮＤＣＥＬＬＩＭＭＵＮＯＧＥＮＩＴＹ：ｖ－Ｈ－ｒａｓＳＵＰＰＲＥＳＳＩＮＧＭＨＣＣＬＡＳＳＩＥＸＰＲＥＳＳＩＯＮＩＮＭＯＵＳＥＦＩＢＲＯＢＬＡＳＴＬｕＹｏｕｙｏｎｇ；吕有勇；Ｓｈｒａｇ...     

THE BLOCKING EFFECTS OF GLYCYRRHIZE URALENSIS AND CHELIDONIUM MAJUS ON MUTAGENESIS INDUCED BY AFLATOXIN B1

ＴＨＥＢＬＯＣＫＩＮＧＥＦＦＥＣＴＳＯＦＧＬＹＣＹＲＲＨＩＺＥＵＲＡＬＥＮＳＩＳＡＮＤＣＨＥＬＩＤＯＮＩＵＭＭＡＪＵＳＯＮＭＵＴＡＧＥＮＥＳＩＳＩＮＤＵＣＥＤＢＹＡＦＬＡＴＯＸＩＮＢ１ＳｈｉＧｕｉｚｎｉ；史桂芝；ＪｉＸｉｎｈｕａ；纪新华；ＬｉａｎｇＹ...     

EXPRESSION OF ONCOGENES DURING INDUCED DIFFERENTIATION OF HUMAN HEPATOCARCINOMA CELL LINE

ＥＸＰＲＥＳＳＩＯＮＯＦＯＮＣＯＧＥＮＥＳＤＵＲＩＮＧＩＮＤＵＣＥＤＤＩＦＦＥＲＥＮＴＩＡＴＩＯＮＯＦＨＵＭＡＮＨＥＰＡＴＯＣＡＲＣＩＮＯＭＡＣＥＬＬＬＩＮＥＣｈａｉＸｉｙｕｎ柴希运ＣｈｅｎＨｕｉｌｉ陈惠黎（ＤｅｐａｒｔｍｅｎｔｏｆＢｉｏｃｈｅｍｉｓ...     

CLONING AND SEQUENCING OF IMMUNOGLOBULINVARIABLE－REGION GENE OF A MONOCLONALANTIBODY SPECIFIC FOR HUMANHEPATOCARCINOMA

ＣＬＯＮＩＮＧＡＮＤＳＥＱＵＥＮＣＩＮＧＯＦＩＭＭＵＮＯＧＬＯＢＵＬＩＮＶＡＲＩＡＢＬＥ－ＲＥＧＩＯＮＧＥＮＥＯＦＡＭＯＮＯＣＬＯＮＡＬＡＮＴＩＢＯＤＹＳＰＥＣＩＦＩＣＦＯＲＨＵＭＡＮＨＥＰＡＴＯＣＡＲＣＩＮＯＭＡＹａｎｇＰｉｎｇ杨萍；ＧａｏＬｅｉ高...     

PRINCIPLES AND APPLICATIONS OF MOLECULAR EPIDEMIOLOGY AND STUDIES OF HUMAN PROSTATIC CARCINOMA

ＰＲＩＮＣＩＰＬＥＳＡＮＤＡＰＰＬＩＣＡＴＩＯＮＳＯＦＭＯＬＥＣＵＬＡＲＥＰＩＤＥＭＩＯＬＯＧＹＡＮＤＳＴＵＤＩＥＳＯＦＨＵＭＡＮＰＲＯＳＴＡＴＩＣＣＡＲＣＩＮＯＭＡＴｚｅ－ｃｈｅｎＨｓｉｅｈ；ＣｈｕｎｙｕｎｇＮｇａｎｄＪｏｓｅｐｈＭ．Ｗｕ（Ｄｅｐｔ...     

LOCALIZATION OF TYPE I AND TYPE Ⅲ PROCOLLAGEN mRNAs IN BREAST SCIRRHOUS CARCINOMA BYIN SITU HYBRIDIZATION

ＬＯＣＡＬＩＺＡＴＩＯＮＯＦＴＹＰＥＩＡＮＤＴＹＰＥⅢＰＲＯＣＯＬＬＡＧＥＮｍＲＮＡｓＩＮＢＲＥＡＳＴＳＣＩＲＲＨＯＵＳＣＡＲＣＩＮＯＭＡＢＹＩＮＳＩＴＵＨＹＢＲＩＤＩＺＡＴＩＯＮＧａｎＹｕｅｔｏ；干月波；ＺｎｅｎｇＳｈｕ；郑树；ＹｕＨａｉ；余海（Ｃ...     

STUDY ON SOLIDIFIED TUMOR VACCINE PREPARED FROM AUTOGENOUS CANCEROUS TISSUE

ＳＴＵＤＹＯＮＳＯＬＩＤＩＦＩＥＤＴＵＭＯＲＶＡＣＣＩＮＥＰＲＥＰＡＲＥＤＦＲＯＭＡＵＴＯＧＥＮＯＵＳＣＡＮＣＥＲＯＵＳＴＩＳＳＵＥＨｕａｎｇＪｉａｏｌｉｎ；黄皎林；ＺｈａｎｇＺａｉｇｅｎ；张哉根；ＨｕａｎｇＨａｉ；黄海；ＨｅＹｕｎｚｈｉ；何云志（Ｘ...     

Expression of gap junction protein Cx43 in cultured human normal and malignant lung cells

Gap junctional intercellular communication-exchange of small molecules and ions between contiguous cells through membranous gap junctional channels-is essential for growth control and tissue homeostasis. This work concerns the functional expression of gap junction protein connexin 43 (Cx43) in normal human lung cells and the changes in lung carcinoma cells. By using Northern blot hybridization analysis and Cx43 immunocytochemical methods, it was observed that cultured normal human embryonic lung cells expressed a high level of Cx43 in both mRNA and protein levels. The Cx43 immunofluorescence was localized at cell membrane regions corresponding to the location of gap junctions. These normal lung cells were competent of intercellular communication function as detected by Lucifer yellow dye transfer. In contrast to normal cells, Cx43 mRNA and protein was not detectable in the carcinoma PG cell line. These tumor cells were defective of intercellular communication function. These results demonstrate that Cx43 is expressed in normal cultured human embryonic lung cells but not in lung tumor cells. The lack of intercellular communication in the lung tumor cell line correlates with dysfunctional intercellular communication. The suggestive role of Cx as a tumor suppersor gene is discussed.     

间隙连接基因Cx43表达对肺癌细胞体内成瘤生长的抑制

目的探讨间隙连接基因表达和细胞通讯功能对肿瘤生长的抑制作用。方法以高转移性人肺癌ＰＧ细胞为材料,该细胞的间隙连接基因Ｃｘ４３表达抑制,细胞通讯功能缺陷。用Ｃｘ４３ｃＤＮＡ转染ＰＧ细胞,分离转染子克隆,与只转染空载体ｃＤＮＡ的对照组ＰＧ进行比较。用Ｎｏｒｔｈｅｒｎ分子杂交和染料传输方法检查间隙连接表达情况,并观察细胞在体外和裸鼠体内生长。结果空载体对照组与未转染组ＰＧ相似,Ｃｘ４３ｍＲＮＡ无表达,通讯功能缺陷,细胞生长快,在软琼脂内集落形成率高（１１．６％）,植入裸鼠体内２８天,平均瘤重３．４７ｇ。转染组细胞Ｃｘ４３ｍＲＮＡ表达升高,通讯功能增强,细胞生长慢,在软琼脂内集落形成率和在裸鼠体内生长速度明显低于对照组,抑制率分别为９０％和７５％。结论间隙连接基因Ｃｘ４３表达对肺癌细胞有抑瘤作用。     

细胞连接蛋白基因在胃癌中的表达研究

目的： 为了系统研究人胃癌基因组中Ｃｘ 基因的表达状况。方法： 本文采用Ｎｏｒｔｈｅｒｎ 印迹杂交和ＲＴＰＣＲ 方法, 对１５ 例人胃癌组织、配对癌旁组织、正常组织及人胃腺癌ＭＧＣ８０３ 细胞株的Ｃｘ２６ 、Ｃｘ３１－１ 、Ｃｘ３２ 、Ｃｘ３３、Ｃｘ３７ 、Ｃｘ４０、Ｃｘ４３ 、Ｃｘ４６ 八种Ｃｘ 基因表达进行了一系列检测。结果：发现在人正常胃粘膜上皮中高水平表达而在胃癌中表达极其微弱或根本无表达的细胞连接蛋白基因的表达规律,首次明确了Ｃｘ 基因在人胃癌基因组中的表达谱。其中人正常胃粘膜上皮细胞中Ｃｘ３２ 、Ｃｘ３７ 、Ｃｘ４３ 在ｍ ＲＮＡ 水平上有高水平表达; 与正常相反, 人胃癌细胞除Ｃｘ４３ 在ｍ ＲＮＡ 水平上有低水平表达外, 其他连接蛋白基因均无转录活性; 而人胃腺癌ＭＧＣ８０３ 细胞株中, Ｃｘ３７ 、Ｃｘ４６ 在ｍ ＲＮＡ 水平上有一定程度的表达。结论：本研究表明Ｃｘ３２ 可能是人胃上皮细胞基因组中维持细胞间隙连接通讯功能的特异表达的Ｃｘ 基因,Ｃｘ４６ 可能是胃癌Ｃｘ 基因表达的一种变异。Ｃｘ３７、Ｃｘ４３ 不是人胃上皮细胞的特异表达基因。本研究证实了Ｃｘ 基因在肿瘤细胞中表达下调,Ｃｘ 基因具有潜在的抑瘤基因的生物学活性。     

Suppression of tumorigenicity of human lung carcinoma cells after transfection with connexin43

The human lung carcinoma cell line PG is defective in gap junctional intercellular communication (GJIC). Connexin43 (Cx43) mRNA, which is expressed in normal human lung cells, is undetectable in these tumor cells. To explore if up-regulation of Cx43 gene expression will suppress malignancy of PG cells, Cx43 cDNA was co-transfected with pSV2neo cDNA into PG cells. Control cells were transfected with the blank vector plus neo cDNA. Several stable Cx43 transfectant clones, which acquired high levels of Cx43 expression and the capacity of GJIC, were compared with control clones and the parental cell line, both of which lacked Cx43 expression and GJIC. The control clones resembled the parental cells in exhibiting high cell growth rate, weak attachment to the substratum and a high frequency of colony formation in soft agar. In contrast to the control cells, Cx43 transfected clones showed reduced growth rate, enhanced attachment to the substratum and inhibition of colony formation in soft agar. In vivo results from nude mice experiments showed high tumorigenicity with control clones and inhibition of tumorigenicity in Cx43 transfected clones. The consistency between in vitro and in vivo results strongly suggests a tumor suppressing effect of the Cx43 gene in human lung carcinoma cells.      

Effective asymmetry in gap junctional intercellular communication between populations of human normal lung fibroblasts and lung carcinoma cells

The dysfunction of homologous and/or heterologous gap junctional intercellular communication (GJIC) has been implicated in tumorigenesis of many kinds of cells. Here we have characterized GJIC and the expression of connexins in six human lung carcinoma cell lines and normal lung fibroblasts (HLF). Compared with HLF, all the carcinoma cells showed reduced or little homologous GJIC. They expressed remarkably reduced connexin(Cx)43 mRNA and variable levels of Cx45 mRNA, but neither Cx43 nor Cx45 protein could be detected. However, using a preloading assay, transfer of calcein was observed between donor HLF cells and first order neighboring recipient tumor cells (recipient cells in 1000-fold excess). Transfer from tumor to HLF cells under the same conditions was not seen, although increasing the ratio of donor tumor cells to recipient HLF cells and plating the cells at low density did reveal weak transfer from tumor cells to HLF. Transfection of Cx43 into giant cell carcinoma PG cells increased homologous communication and eliminated the rectifying behavior of heterologous communication. This indicates that the apparent rectification of dye transfer between normal and tumor cells was a product of low rates of heterologous transfer linked to (i) rapid dilution of the dye to below detectable limits through a very well coupled cell population (tumor to HLF) and (ii) concentration of dye in immediate neighbors in a poorly coupled cell population (HLF to tumor cells). These results suggest that the coupling levels may need to exceed a certain threshold to allow propagation of signals over a sufficient distance to affect behavior of a cell population. We propose that the relative rates of heterologous and homologous coupling of cell populations and the 'pool size' of shared metabolites in tumor cells and the surrounding normal tissue are likely to be very important in the regulation of their growth.     

Suberoylanilide hydroxamic acid enhances gap junctional intercellular communication via acetylation of histone containing connexin 43 gene locus

A histone deacetylase (HDAC) inhibitor, suberoylanilide hydroxamic acid (SAHA), induces apoptosis in neoplastic cells, but its effect on gap junctional intercellular communication in relation to apoptosis was unclear. Therefore, we carried out a comparative study of the effects of two HDAC inhibitors, SAHA and trichostatin-A, on gap junctional intercellular communication in nonmalignant human peritoneal mesothelial cells (HPMC) and tumorigenic ras oncogene-transformed rat liver epithelial cells (WB-ras) that showed a significantly lower level of gap junctional intercellular communication than did HPMC. Gap junctional intercellular communication was assessed by recovery rate of fluorescence recovery after photobleaching. Treatment of HPMC with SAHA at nanomolar concentrations caused a dose-dependent increase of recovery rate without inducing apoptosis. This effect was accompanied by enhanced connexin 43 (Cx43) mRNA and protein expression and increased presence of Cx43 protein on cell membrane. Trichostatin-A induced apoptosis in HPMC but was less potent than SAHA in enhancing the recovery rate. In contrast, treatment of WB-ras cells with SAHA or trichostatin-A induced apoptosis at low concentrations, in spite of smaller increases in recovery rate, Cx43 mRNA, and protein than in HPMC. Chromatin immunoprecipitation analysis revealed that SAHA enhanced acetylated histones H3 and H4 in the chromatin fragments associated with Cx43 gene in HPMC. These results indicate that SAHA at low concentrations selectively up-regulates Cx43 expression in normal human cells without induction of apoptosis, as a result of histone acetylation in selective chromatin fragments, in contrast to the apoptotic effect observed in tumorigenic WB-ras cells. These results support a cancer therapeutic and preventive role for specific HDAC inhibitors.     

Expression of cell adhesion molecules and connexins in gap junctional intercellular communication deficient human mesothelioma tumour cell lines and communication competent primary mesothelial cells

Gap junctional intercellular communication (GJIC) has been reportedto be markedly reduced in human mesothelloma tumour cell linescompared with primary mesothelial cells. Iminunofluorescencestainings have shown that the gap junction protein connexin43(Cx43) is expressed In both malignant and normal mesothelialcells. In this study the mRNA expression of Cx43 and three differentconnexlns—Cx37, Cx40 and Cx45, which are highly expressedin lung tissue—was investigated in eight human mesotheliomacell lines, and in human primary mesothellal cells from severaldonors. The expression of the intercellular adhesion moleculesA-CAM (N-cadherln) and L-CAM (E-cadherin) was studied at theprotein level. No mRNA expression of Cx37, Cx40 or Cx45 in eithermesothelioma tumour cells or the primary mesothelial cells wasdetected. Cx43 was expressed at both the mRNA and the proteinlevel, in seven out of eight mesothelloma cell lines, as wellas in all the primary mesothellal cell cultures. The intercellularadhesion molecule A-CAM was expressed at the cell—cellborders In six out of seven mesothelioma cell lines, as wellas in normal mesothellal cells. No expression of L-CAM was observedin these cells. The results suggest that Cx43 and A-CAM arethe major proteins in gap and adherens Junctions respectivelyin human mesothellal cells. Most mesothelioma tumour cell lineswith markedly reduced GJIC still express both Cx43 and A-CAM.Only one of our mesothelloma tumour cell lines severely deficientin GJIC lacks both the gap junction protein Cx43 and the celladhesion molecule A-CAM.     

Down-regulation of Cx43 by retroviral delivery of small interfering RNA promotes an aggressive breast cancer cell phenotype

Connexins are gap junction proteins that assemble into channels that mediate direct intercellular communication. Connexins are well-documented tumor suppressors and are thought to regulate both cell growth and differentiation. As previously reported, most human breast tumors and cell lines down-regulate gap junctions or have defective gap junctional intercellular communication. Furthermore, overexpression of connexins in breast cancer cells inhibits tumor growth in vivo. In this study, we hypothesize that controlled Cx43 down-regulation would induce breast tumor cells to acquire a more aggressive phenotype. Here we report that Cx43 was down-regulated in both normal rat kidney (NRK) cells and human breast cancer cell lines (MDA-MB-231 and Hs578T) by transfection with chemically synthesized small interfering RNA (siRNA) or short hairpin RNA generated from a retroviral infection. Furthermore, we show that retroviral delivery and expression of siRNA directed to different coding regions of Cx43 resulted in differential levels of Cx43 silencing and impaired gap junctional intercellular communication. Cx43-silenced Hs578T cells grew faster and were more migratory. Finally, Western blot analysis revealed that down-regulation of Cx43 resulted in decreased expression of thrombospondin-1, an antiangiogenesis molecule, and increased expression of vascular endothelial growth factor. Taken together, these results suggest that Cx43 is required for maintaining cell differentiation and the regulation of molecules important in angiogenesis.     

Differential effect of subcellular localization of communication impairing gap junction protein connexin43 on tumor cell growth in vivo

There is a large body of evidence suggesting the connexin gap junction proteins appear to act as tumor suppressors, and their tumor inhibitory effect is usually attributed to their main function of cell coupling through gap junctions. However, some cancer cells (e.g. the rat bladder carcinoma BC31 cell line) are cell-cell communication proficient. Using specific site-directed mutagenesis in the third membrane-spanning (3M) domain of connexin43 (Cx43), we abolished the intrinsic gap junction intercellular communication (GJIC) in BC31 cells either by closing the gap junctional channels or by disruption of the transport of connexin complexes to the lateral membrane. Clones of BC31 cells transfected with a dominant negative Cx43 mutant giving rise to gap junctional channels, permeable only for a small tracer (neurobiotin), displayed accelerated growth rate in vivo, showing the critical role of selective gap junctional permeability in the regulation of cell growth in vivo. The use of other dominant-negative mutants of Cx43 also suggested that the effect of impaired communication on the tumorigenicity of cancer cells depends on the subcellular location of connexin. Inhibition of intrinsic GJIC in BC31 cells by sequestering of Cx protein inside the cytoplasm, due to expression of dominant-negative transport-deficient Cx43 mutants, did not significantly enhance the growth of transfectants in nude mice, but occasionally slightly retarded it. In contrast, augmentation of GJIC in BC31 cells by forced expression of wild-type Cx43, or a communication-silent mutant, fully suppressed tumorigenicity of these cells. Overall, these results show that cell coupling is a strong, but not the sole, mechanism by which Cx suppresses growth of tumorigenic cells in vivo; a GJIC-independent activity of Cx proteins should be considered as another strong tumor-suppressive factor.     

Reduced levels of connexin43 in cervical dysplasia: inducible expression in a cervical carcinoma cell line decreases neoplastic potential with implications for tumor progression

Loss of gap junctional intercellular communication (GJIC) has been linked to aberrant proliferation and an enhanced neoplastic phenotype. Many human tumors, including the cervical carcinoma line HeLa, have been reported to be deficient in expression of the gap junction protein connexin43 (Cx43) and GJIC. To determine if this is an early event in carcinogenesis, we utilized immunohistochemistry to screen a series of cervical biopsy samples and demonstrated a major reduction in Cx43 expression in dysplastic regions compared to normal epithelia. To determine whether this loss influences the neoplastic behavior of cervical carcinoma cells, we have constructed HeLa cell lines in which Cx43 expression can be induced in response to doxycycline. This approach allows for the discrimination of Cx43-mediated effects from those due to pre-existing clonal heterogeneity. Cx43 induction in these cells led to assembly of functional junctions but did not alter growth control in vitro as measured by logarithmic growth, saturation density or focus formation when in co-culture with growth-controlled fibroblasts. However, Cx43 induction decreased two indices of neoplasia: it reduced anchorage-independent growth and attenuated the growth rate of tumor xenografts. These results indicate that established HeLa cell lines are unresponsive to Cx43-mediated signals which are thought to mediate growth control of non-transformed cells, however, Cx43 expression can still reduce aspects of the neoplastic phenotype of these cells, indicating that loss of connexin signaling in dysplastic cells may contribute to their neoplastic progression.