Influence of bcl-2-related proteins on matrix metalloproteinase expression in a rat glioma cell line.

The expression of bcl-2-related proteins has been shown to be a key element in tumoral malignancy. The degradation of the extracellular matrix (ECM) by specialized matrix metalloproteinases (MMPs) is another major step in tumor invasion and metastasis. We have examined, in a rat glioma cell line A15A5, the effect of the stable transfection of human bcl-2, bax and bcl-xl on MMPs expression. Using a zymographic assay, we found that all transfected cell lines expressed a gelatinase activity which is predominantly associated with MMP-9. In bcl-2 and bcl-xl transfected cells, the transcription of MMP-9 was decreased compared to that of control or bax transfected cells. In addition, in bax transfected A15A5, we observed a down regulation of TIMP-1, the inhibitor of MMP-9. These results suggest that the ratio between MMP-9 and its inhibitor TIMP-1 is tightly controlled in cells overexpressing bcl-2 related proteins (i.e., high ratio in bax transfected A15A5 and low ratio in bcl-2 transfected A15A5). However, MMPs secreted by bcl-2 transfected cells were still capable of hydrolyzing FasL present on human lymphocytes. Our results suggest that the expression of bcl-2 related proteins could participate in the regulation of MMP-9/TIMP-1 in gliomas.

CD44 isoforms with exon v6 and metastasis of primary N0M0 breast carcinomas.

New isoforms of CD44 with alternatively spliced exons have recently been described. Expression of exon v6 seems to be of particular interest. It has indeed been associated with poorer outcome of breast cancer patients with node invasion at diagnosis. However, no data were available for patients N0M0 (with neither metastasis nor node invasion at diagnosis). Moreover, previous statistical analyses were realized using immunohistochemical methods to detect CD44v6 expression although several variants with exon v6 have been described. We investigated expression of isoforms containing CD44v6 using an RT-PCR approach and a panel of 25 normal breast specimens, 10 mammary fibroadenomas, 8 cystic samples and 52 primary breast tumors (38 invasive N0M0). Normal breasts, fibroadenomas, and cysts all express the same variant, A (with exon v6 only), while several transcripts are amplified in tumors. Expression of variants other than A correlates with acquisition of a malignant phenotype. Invasive cancers also express additional variants in comparison with in situ carcinomas. Metastasis capacities seem to be associated with transcription of variants other than A but also with no transcription of some of them, variants D (with exons v6 and v10) and L (with exons v6 to v10). Expression of variants D and L correlates with higher percentages of disease-free survival and better outcome. Expression of CD44 splice variants with exon v6, as detected by RT-PCR, might be a useful prognostic factor for breast cancer. However, since the series size is small, our results need to be confirmed by later studies on a larger number of patients.

Expression of CD44 spliced variants with both exons v9 and v10 in primary N(-)M(-) breast carcinomas correlates with metastasis.

We analyzed the representation of CD44 isoforms with both exons v9 and v10 among CD44 total amount and also examined correlation between their expression, clinical parameters and survival. We used a semi-quantitative RT-PCR reaction and a panel of 25 normal breast specimens, 10 mammary fibroadenomas, 8 cystic samples and 52 primary breast tumors. CD44 expression level was statistically higher in malignant tumors than in normal breast tissues (p = 0.038) or in fibroadenomas (p = 0.047) and correlated with histological grading, p = 0.047. Ratios CD44 variants with both exons v9 and v10/ total CD44 were similar in normal breast tissues and fibroadenomas but lower in the cystic samples. In primary N(-)M(-) breast tumors, unfavourable outcome and relapse were correlated with low ratios.

Are CD44 spliced variants involved in human breast cancer metastasis?

Expression of CD44 isoforms has been investigated on normal breasts, fibroadenomas, cysts and breast cancers. Carcinomas express additional variants in comparison with normal breasts while fibroadenomas and cysts do not. Invasive cancers also express more variants than in situ carcinomas. Recent studies tend to demonstrate that overexpression of CD44 is not a survival prognostic factor whereas expression of exon 2v and/or 3v could be. Results for exons 4v to 10v are presently conflicting. Further studies will then be necessary to clarify the role of CD44 isoforms in mammary carcinogenesis and metastasis. Metastatic capacity could be linked with expression of additional variants but also with no transcription of variants associating exon 6v with either exon 10v or both exons 9 and 10v.

CD44 exon 6 expression as a possible early prognostic factor in primary node negative breast carcinoma.

Breast cancer is the most common female malignancy affecting approximately one woman in eight. Many attempts have been made to define markers which may have potential clinical applications in diagnosis as well as therapy. New isoforms of CD44 with alternative spliced exons have recently been described. We studied the expression of CD44 exon 6 using a semi-quantitative RT-PCR reaction on a panel of 25 normal breast specimens, 10 mammary fibroadenomas, eight cystic samples and 52 primary breast tumors. Significant correlation was found between CD44 exon 6 expression and the overall survival of the N-M-population, P = 0.032, (logrank test by Mantel's method). The same result was also observed for the disease-free survival, P = 0.000002 (logrank test by Mantel's method). CD44 exon 6 expression, as detected by our RT-PCR-based method, might be a useful prognostic indicator of metastasis in breast cancer. However, these preliminary results need to be confirmed by later retrospective and prospective studies on a larger number of patients.

Loss of heterozygosity of the RB gene is a poor prognostic factor in patients with osteosarcoma.

PURPOSE: The usual therapy of osteosarcoma is neoadjuvant chemotherapy, followed by surgery, then by postoperative chemotherapy. There is no prognostic factor to predict, at diagnosis, the histologic response and final outcome. Inactivation of the retinoblastoma-susceptibility gene RB is associated with the pathogenesis of several human cancers. In primary osteosarcomas, loss of heterozygosity (LOH) at the RB locus has been found in greater than 60% of cases. The aim of this study was to determine the potential early prognostic value of LOH of RB gene on the biopsy material at diagnosis. PATIENTS AND METHODS: Forty-seven patients with primary osteosarcoma, treated in four French institutions, were studied. LOH was studied by polymerase chain reaction (PCR) of an informative RB DNA polymorphism. RESULTS: Assessment of LOH at the RB gene could be completed on 34 heterozygous patients only. LOH was found in 24 cases (70%). The event-free survival (EFS) rate at 60 months is 100% for patients without LOH, 43% for all patients with RB LOH, and 65% for nonmetastatic patients with RB LOH. The difference in EFS is highly significant at P = .008 and P = .024, respectively. Histologic response after preoperative chemotherapy did not show significant correlation with LOH status. CONCLUSION: RB gene LOH appears to be an early predictive feature for osteosarcomas that indicates a potential unfavorable outcome. RB LOH study might shortly help to identify high-risk patients earlier. If this is verified, therapy could then be adapted earlier to the individual's real risk of relapse.

E-cadherin mRNA expression in breast carcinomas correlates with overall and disease-free survival.

E-cadherin (Epithelial-cadherin) is a subclass of the cadherin family that plays a major role in the maintenance of intercellular junctions in epithelial tissues. E-cadherin is also involved in the interactions between epithelial cells and T lymphocytes. In order to explore the relationship between E-cadherin expression, cancer invasion and metastases in vivo, we estimated its expression in normal breast specimens, fibroadenomas, cystic samples and primary breast carcinomas using a semiquantitative reverse transcription-polymerase chain reaction. The relationship between E-cadherin expression, survival and disease-free survival was also investigated. In comparison with normal breasts, 70% of the primary tumors showed reduced expression of E-cadherin suggesting that downregulation of this cell adhesion molecule is a common event in breast carcinoma. Significant correlation was found between E-cadherin expression and the histological classification. Most of the advanced tumors grades (10/13 tumors with grade III) presented decreased E-cadherin expression. No correlation was found between E-cadherin expression, estrogen and progesteron receptors, age and menopausal status at diagnosis. However, disease-free and overall survival was associated with E-cadherin expression. Patients showing poorly expressed E-cadherin in tumor tissue had a worse prognosis. The same results were observed for women without lymph node invasion or metastasis at diagnosis even when they were grouped according to their histological grade for statistical analysis. Therefore, E-cadherin mRNA expression in invasive breast carcinomas might be an early prognostic factor of metastasis.