Increased expression of the matrix metalloproteinase 2 in differentiating Tera 2 human embryonal carcinoma cells

Microinvasive germ cell tumor of the testis

Microinvasive germ cell tumor (MGCT) consists of a limited number of malignant germ cells in the intertubular tissue of the testis. The cells have large nuclei, prominent nucleoli, abundant clear cytoplasm, and distinct cellular borders in hematoxylin and eosin staining. MGCT can be the first stage of malignancy in the development of testicular germ cell tumor (TGCT). Biopsies from men with maldescended testes have been reported to contain intratubular germ cell neoplasia, unclassified (IGCN) and MGCT in 1.8% of the examined cases (95% CI 0.5-4.6%). MGCT has also been found in testes of subfertile men and in the contralateral testis of patients with TGCT. MGCT is a frequent finding (19%) in the testicular tissue adjacent to an overt TGCT. Men with a high risk of TGCT may gain from screening for precursor lesions of TGCT with ultrasonography of the testes followed by a testicular biopsy if suspicious abnormalities are found: Treatment is high-voltage radiotherapy for intratubular germ cell neoplasia (IGCN), and orchidectomy for MGCT and germ cell tumor in situ, either intratubular seminoma or intratubular embryonal carcinoma. After local treatment, patients with precursor lesions can be followed with a surveillance program. The mRNA levels of invasion-related genes were evaluated based on a DNA microarray data set, and we found two gene abnormalities most relevant for the invasion of malignant germ cells: matrix metalloproteinase 9 (MMP9) and plasminogen activator, urokinase (PLAU) genes were up-regulated in a study comparing tissue samples of TGCT and IGCN.

Chromosomes, genes, and development of testicular germ cell tumors

A literature review found 265 articles on testicular germ cell tumors (TGCTs) detailing the copy number of chromosomal regions and expression of 245 genes. An initial precursor stage, intratubular germ cell neoplasia (IGCN), is characterized by triploidization and an upregulation of KIT, ALPP, CCDN2, and ZNF354A, and a downregulation of CDKN2D. TGCT regularly have a series of chromosomal aberrations: a decrease in copy number at 4q21 approximately qter and 5q14 approximately qter; an increase at 7p21 approximately pter, 7q21 approximately q33, and 8q12 approximately q23 (especially high increase in seminoma); a decrease at 11p11 approximately p15 and 11q14 approximately q24; an increase at 12p11 approximately pter; a decrease at 13q14 approximately q31; an increase of 17q11 approximately q21 (only for nonseminoma); a decrease of 18q12 approximately qter; and an increase at 21q21 approximately qter, 22q11 approximately qter (only for seminoma), and Xq. Macroscopically overt TGCT is associated with a characteristic series of abnormalities in the retinoblastoma pathway including upregulation of cyclin D2 and p27 and downregulation of RB1 and the cyclin-dependent kinase inhibitors p16, p18, p19, and p21. TGCT thus has a synergistic pattern in gene expressions of the retinoblastoma pathway that is rare in other malignancies.

Significance of the response of quiescent cell populations within solid tumors in cancer therapy

In analyzing the response of quiescent (Q) cells in solid tumors, we have developed a combined method with a micronucleus (MN) assay and the identification of proliferating (P) cells by 5-bromo-2'-deoxyuridine (BrdU) and an anti-BrdU monoclonal antibody. Using this method, the responses of Q tumor cells as well as total tumor (P + Q) cells within murine solid tumors to various DNA-damaging treatments were evaluated. Based on this evaluation, combining with tirapazamine, a well-known bioreductive agent, and/or heat treatment at mild temperatures was thought to be a promising modality for cancer therapy in terms of conventional anticancer treatment-resistant Q cell control. Recently, our method for detecting the Q-cell response using P cell labeling with BrdU and the MN frequency assay was also shown to be applicable to an apoptosis detection assay. Meanwhile, our method for detecting the intratumor Q-cell response was also applicable toward high linear energy transfer radiation, including reactor neutrons. Thus, using our method, a new neutron capture compound that has the potential to be distributed in neutron capture therapy-resistant intratumor Q cell populations is now under development.

Overview of matrix metalloproteinase expression in cultured human cells

The matrix metalloproteinases (MMP) have been implicated in tumor invasion and metastasis both by immunohistochemical studies and from the observation that specific metalloproteinase inhibitors block tumor invasion and metastasis. Oligonucleotide primers for thirteen MMPs (MMP-1, MMP-2, MMP-3, MMP-7, MMP-8, MMP-9, MMP-10, MMP-11, MMP-12, MMP-13, MMP-14, MMP-15, MMP-16) were optimized for use in RT-PCR. A semi-quantitative RT-PCR assay was used to determine the pattern of MMP mRNA expression in 84 normal and transformed or carcinogen transformed human cell lines and strains derived from different tissues. The results demonstrate one or more cell lines which express thirteen members of the MMP family. In addition, various oncogene transfected human fibroblast cell strains were analyzed for MMP expression. We confirm that over-expression of the H-ras oncoprotein correlates with up-regulation of MMP-9 and demonstrate that over-expression of v-sis also up-regulates MMP-9. A cell line immortalized following myc expression was found to up-regulate MMP-7, MMP-11 and MMP-13. Inappropriate expression of several MMP mRNAs was detected in breast, prostate, bone, colon and oral tumor derived cell lines. Identification of at least one cell line expressing each of thirteen MMPs and the observation of oncogene induced expression of several MMPs should facilitate analysis of the transcriptional mechanisms controlling each MMP.

Toxicity of ethanol in low concentrations. Experimental evaluation in cell culture

PURPOSE

To define the threshold ethanol concentration that is toxic to cultured cells.

METHODS

Three malignant cell lines and freshly isolated normal rat hepatocytes were exposed to 0-50% (vol.) ethanol (concentrations used were 0, 5, 10, 15, 20, 25, 30, 40 and 50%) on tissue culture plates for 0.25-60 min (exposure times used were 0.25, 5, 10, 20, 30, 40 50 and 60 min). Cytotoxicity was estimated by trypan blue exclusion test and from 3H-thymidine incorporation.

RESULTS

All cells were killed by a 15-s exposure to 30-40% ethanol while a concentration as low as 15-20% gave a total response after 5-10-min exposures. After a one-hour exposure of F9 carcinoma cells and hepatocytes, a total or nearly total response was achieved with 10% ethanol. The cytotoxic effect was thus dependent both on the exposure time and on the concentration of ethanol. There were no significant differences in ethanol tolerance among the cell types.

CONCLUSION

Ethanol seemed to kill cells in the cell culture effectively in much lower concentrations than those currently used in tumour ablation.

Matrix metalloproteinase expression during mouse peri-implantation development

PROBLEM

The purpose of this study was to define the temporal expression and to quantitate the mRNA levels of collagenase, 72 kDa, 92 kDa, and membrane-type matrix metalloproteinase during the peri-implantation period of pregnancy in the mouse uterus. Embryonic expression of 72 kDa and 92 kDa matrix metalloproteinases, as well as interleukin 1 alpha, was also investigated.

METHODS

Uterine matrix metalloproteinases were detected using gelatin substrate gel electrophoresis (zymography) and reverse-transcription polymerase chain reaction methodology was used to detect and quantitate different mRNA species in the mouse uterus and blastocyst.

RESULTS

Collagenase, 72 kDa, and 92 kDa matrix metalloproteinases are developmentally regulated during the peri-implantation period of pregnancy, but membrane-type matrix metalloproteinase appears to be expressed constitutively. Matrix metalloproteinase mRNA levels have been quantitated and confirm the observed developmental expression patterns. Prominent expression of bot 92 kDa matrix metalloproteinase and interleukin 1 alpha was observed in blastocysts during outgrowth while weak expression of the 72 kDa matrix metalloproteinase was detected.

CONCLUSIONS

The date provide evidence of matrix metalloproteinase expression in vivo and substantiate their potential role in tissue remodeling prior to and during blastocyst implantation. Expression of interleukin 1 alpha, 92 kDa, and 72 kDa matrix metalloproteinases suggests that these proteins are important for trophoblast invasion associated with implantation of the early embryo.