c-myc癌基因在大肠组织中表达的免疫组织化学和原位杂交研究

本文应用 c-myc 癌基因蛋白免疫组织化学和 mRNA 原位杂交方法研究了 c-myc 癌基因在大肠组织中的表达,并以胎盘作为阳性对照。发现在胎盘合体滋养叶细胞和结肠粘膜表面上皮都有 c-myc 癌基因的表达。结肠肿瘤 c-myc 表达增加,腺癌表达高于腺瘤。腺瘤中以绒毛状腺瘤表达最高。研究表明 c-myc 癌基因表达并不绝对与细胞增殖状态相关。     

Lectin binding patterns in normal, metaplastic, and neoplastic gastric mucosa.

We investigated lectin binding patterns on tissue specimens of normal and metaplastic gastric surface mucosae, gastric adenomas, and intestinal and diffuse-type gastric carcinomas. Compared with normal gastric mucosa, metaplastic mucosa exhibited an increase of ConA binding and decreases of WGA, PNA, UEA-1, and DBA binding in the cytoplasm, and decreases of ConA, PNA, and UEA-1 binding at the luminal surface. Intestinal carcinomas were similar to metaplastic gastric surface mucosa in ConA, WGA, and UEA-1 binding in the cytoplasm, while diffuse-type carcinomas were similar to normal gastric mucosa in WGA and UEA-1 binding in the cytoplasm. Adenomas were similar to intestinal carcinomas in ConA and UEA-1 binding in the cytoplasm, but were different from intestinal carcinomas in Con A and UEA-1 binding at the luminal surface. For UEA-1, normal and metaplastic gastric surface mucosae did not show a significant difference between the blood type A, AB, B group and the O group. Intestinal and diffuse carcinomas and adenomas also did not show such a difference between the blood groups. For DBA, normal gastric surface mucosa showed a significant difference between the blood type B, O group and the A, AB group. Normal gastric mucosa of the blood type A, AB group was frequently positive for DBA binding in the cytoplasm and at the luminal surface. Metaplastic mucosa did not show a significant difference between the blood groups. Intestinal and diffuse-type carcinomas and adenomas also did not show a difference between the blood groups. DBA binding in the cytoplasm of intestinal carcinomas and adenomas was more frequently positive than that of normal and metaplastic mucosae, except for normal gastric mucosa of the blood type A, AB group. Compared with diffuse-type carcinomas, intestinal carcinomas were accompanied by a significant increase of ConA binding and decreases of WGA and PNA binding in the cytoplasm.     

Localization of alpha-casein gene transcription in sections of epoxy resin-embedded mouse mammary tissues by in situ hybridization

The objective of our study was to evaluate the suitability of aldehyde-fixed, epoxy resin-embedded tissue for efficient and reproducible detection of casein mRNA in mouse mammary tissue by in situ hybridization. We used mouse alpha-casein-specific, 35S-labeled riboprobes generated from a Gemini-3 vector. Both complementary (anti-sense) and homologous (sense) RNA probes were utilized in our study (specific activity ranged from 5-7 x 10(8) cpm/micrograms). We tested the stability of newly synthesized [3H]-uridine-labeled RNA in tissue sections subjected to epoxy plastic solvents and found that no detectable loss of label occurred during preparation of semi-thin (1-2 micron) plastic sections for situ hybridization. In addition, it was possible to detect alpha-casein mRNA in deplasticized sections of mammary gland tissue taken from normal, pregnant, or lactating mice, pre-neoplastic mammary alveolar hyperplasias, explant cultures, and mammary tumors. A positive hybridization signal was consistently obtained in sections of mammary tissues where the estimated average copy number for total casein mRNA was greater than or equal to 250/cell. In mammary tumors, where the estimated casein mRNA content was much lower (less than 5/cell), our positive hybridization signal occurred in regions of the tumor that, in consecutive sections, stained positive for casein by immunoperoxidase. After formaldehyde-glutaraldehyde fixation, loss of hybridizable RNA from epoxy-embedded tissues and sections appears to be minimal. Image resolution was greatly enhanced over frozen or paraffin sections of mammary tissue. Non-specific binding of the radioactive probes was very low. Protease treatment of the sections was not necessary for detection of hybridizable signal.     

Amplification of the expression of the c-myc oncogene in bronchial epidermoid carcinoma in man

Squamous cell lung carcinomas from 10 untreated patients were examined for the state of the oncogene c-myc. Blot hybridization experiments have demonstrated the amplification of the oncogene of about six fold in only one tumor. The oncogene amplification was not detected in normal tissues of patients. The analysis of RNA by Northern blot revealed the presence in the seven tumors examined of a 2.4 kb c-myc RNA band. The level of c-myc expression evaluated by dot blot analysis was 5 to 14 fold greater in tumors than that of histologically normal lung of the same patients.     

Analysis of the expression of the oncogene c-myc in human breast adenocarcinoma

The c-myc oncogene was characterized and its expression analyzed in 32 mammary adenocarcinomas and in 2 benign breast tumors from 34 untreated patients. Southern blot hybridization experiments have demonstrated the amplification of the oncogene (3 to 30 fold) in 3 carcinomas. The analysis of total RNA by Northern blot revealed the presence of a 2.4 kb c-myc RNA band. In 7 out of 10 carcinomas from patients with 3 or more than 3 lymph node metastases the level of c-myc expression evaluated by dot blot analysis was 4 to 14 fold greater than that of normal human tissues. In only 5 out of 22 carcinomas from patients without lymph node metastases or less than 3 invaded nodes the level of c-myc expression was also higher (4 to 10 fold). The level of c-myc expression was not significantly enhanced in the 2 benign tumors. It is suggested that the c-myc gene activation could be associated to a higher degree of malignancy of mammary carcinomas.     

Inhibition of retroviral replication by anti-sense RNA.

We tested the effect of anti-sense RNA on the replication of avian retroviruses in cultured cells. The replication of a recombinant retrovirus carrying a neomycin resistance gene (neor) in the anti-sense orientation was blocked when the cells expressed high steady-state levels of RNA molecules with neor in sequence in the sense was blocked when the cells expressed high steady-state levels of RNA molecules with neor sequences in the sense orientation, i.e., complementary to the viral sequence. Viral DNA bearing neor sequences was not detected specifically in host cells where this anti-sense RNA inhibition of viral replication occurred. These observations suggest that anti-sense RNA inhibition may be a useful strategy for the inhibition of retroviral infections.     

Abnormal subcellular distribution of mature MUC2 and de novo MUC5AC mucins in adenomas of the rectum: immunohistochemical detection using non-VNTR antibodies to MUC2 and MUC5AC peptide

Anti-mucin variable number tandem repeat (VNTR) antibodies have been used previously to demonstrate the de novo presence of MUC5AC and MUC6 mucin in colorectal adenomas and increased synthesis of MUC2, the major secreted mucin in normal colorectal mucosa. Here we examined secreted mucins in tubular, tubulovillous and villous adenomas of the rectum using non-VNTR antibodies designed to assess mature mucin. Mucin gene messenger RNAs were detected by in situ hybridization. The anti-MUC2 non-VNTR antibody in the goblet cells of adenomas revealed a staining pattern of increased cytoplasmic, Golgi and membrane staining with no change in goblet vesicle reactivity compared with normal controls. In addition, blank goblet cell vesicle immunostaining for MUC2 was found in the transitional mucosa adjacent to all types of adenoma. Although a trend to overexpression of MUC2 was observed with in situ hybridization this was not detected with immunohistology. De novo synthesis of MUC5AC, but not MUC5B or MUC6 mucin was seen in all adenomas and transitional mucosa using immunohistochemistry. There was no correlation of MUC2 or MUC5AC mucin with polyp size or the grade of dysplasia using the non-VNTR antibodies. This study demonstrates that anti-mucin non-VNTR antibodies reveal a different subcellular-localization in rectal adenomas compared with normal colorectal mucosa. Further, this pattern is in contrast to that reported for anti-mucin VNTR antibodies. Combined use of these reagents may benefit future assessment of these cancers.     

IL-2 production in human T lymphotropic virus I-infected leukemic T lymphocytes analyzed by in situ hybridization

In situ hybridization studies were performed with 35S-labeled anti-sense RNA probes to study IL-2 mRNA expression in three human T lymphotropic virus I-infected T cell lines at the single cell level. In HuT 102, MT-2, and MT-4 cells, IL-2 mRNA-expressing cells were identified, occurring at frequencies of 2 x 10(-2), 8 x 10(-3), and 5 x 10(-3), respectively. In these cell lines, IL-2 mRNA was not detectable in RNA extracted from whole adult T cell leukemia cell populations because of dilution by other RNA species from the vast majority of cells that do not contain IL-2 mRNA. The data indicate the possibility of paracrine growth stimulation via IL-2 and its receptor even in those human T lymphotropic virus I-infected T cell populations that apparently lack IL-2 activity when analyzed by conventional assay procedures.     

Iron-binding proteins in human colorectal adenomas and carcinomas: an immunocytochemical investigation.

By immunocytochemistry, the presence of major iron-binding proteins (lactoferrin, transferrin and ferritin) was investigated in tubular adenomas (12 cases), villous adenomas (7 cases), carcinomas of the large bowel and rectum (39 cases) and lymph nodes involved in carcinomas (8 cases); 5 samples of colonic inflammatory pseudopolyps were also studied. Dysplastic areas of tubular and villous adenomas as well as adenocarcinomas and colloid carcinomas showed a variable cytoplasmic immunoreactivity for all antisera, although no staining was noted in some cases; tubular adenomas without dysplasia and colonic inflammatory pseudopolyps were always unstained. Metastatic elements present in lymph nodes maintained the immunohistochemical staining for iron-binding proteins. An autoctone production of lactoferrin, transferrin and ferritin by tumour cells may be hypothesized in relation to the increased requirement of iron for the turnover of rapidly dividing cells.