Gene Expression Profiling of 2-(4-Aminophenyl)benzothiazole-resistant MCF-7 Cells Using cDNA Microarrays.

Background: CJM126, 2-(4-aminophenyl) benzothiazole, is a potent inhibitor of human-derived breast carcinoma cell lines. Previous studies have shown that CJM126 elicits concentration-dependent, biphasic growth inhibitory effects against a panel of estrogen receptor-positive and receptor-negative human mammary carcinoma cell lines by a mechanism which has not been fully elucidated.

Materials And Methods: In an effort to understand the mechanism(s) of resistance to CJM126, the present study used cDNA microarrays (Clontech Laboratories, Inc.

Variation in RNA expression and genomic DNA content acquired during cell culture.

Specific chromosomal abnormalities are increasingly recognised to be associated with particular tumour subtypes. These cytogenetic abnormalities define the sites of specific genes, the alteration of which is implicated in the neoplastic process. We used comparative genomic hybridisation (CGH) to examine DNA from different breast and ovarian cancer cell lines for variations in DNA sequence copy number compared with the same normal control.

A molecular cytogenetic approach to studying platinum resistance.

The technique of comparative genomic hybridisation (CGH) has until recently been used to screen for common genomic abnormalities in fresh tumour material; it has identified previously unrecognised regions of amplification associated with poor prognosis subtypes of breast cancer and lymphoma. Our group has applied this technique to resistant cell lines and their sensitive counterparts in order to define chromosomal abnormalities associated with acquired drug resistance. We have demonstrated the applicability of this technique to the study of drug resistance using cell lines with known mechanisms of resistance.

Genomic imbalances associated with acquired resistance to platinum analogues.

During the past several years, a panel of human tumor cell lines (predominantly ovarian) with acquired resistance to cisplatin, the orally bioavailable analogue JM216, and the structurally hindered analogue AMD473, has been established and characterized for underlying mechanisms of resistance. We have examined these resistant cell lines for gains and losses of DNA associated with the acquisition of resistance using the molecular cytogenetic technique of comparative genomic hybridization. Our comparison of three analogues has shown the most frequently observed changes to include amplification of 4q (5/7) and 6q (5/7), followed by amplification of 5q (3/7).

Abnormalities of chromosomes 8, 11, 14, and X in T-prolymphocytic leukemia studied by fluorescence in situ hybridization.

Twenty-one patients with T-prolymphocytic leukemia (T-PLL) were studied by FISH to characterize abnormalities of chromosomes 8, 11, 14, and X. A higher percentage of abnormalities of these chromosomes was detected by FISH than by cytogenetics. Seventy-one percent had inv(14) (q11q32)/t(14;14)(q11;q32).