Estimating the magnitude of trastuzumab effects within patient subgroups in the HERA trial.

BACKGROUND: Trastuzumab (Herceptin(R)) improves disease-free survival (DFS) and overall survival for patients with human epidermal growth factor receptor 2 (HER2)-positive early breast cancer. We aimed to assess the magnitude of its clinical benefit for subpopulations defined by nodal and steroid hormone receptor status using data from the Herceptin Adjuvant (HERA) study. PATIENTS AND METHODS: HERA is an international multicenter randomized trial comparing 1 or 2 years of trastuzumab treatment with observation after standard chemotherapy in women with HER2-positive breast cancer. In total, 1703 women randomized to 1-year trastuzumab and 1698 women randomized to observation were included in these analyses. Median follow-up was 23.5 months. The primary endpoint was DFS. RESULTS: The overall hazard ratio (HR) for trastuzumab versus observation was 0.64 [95% confidence interval (CI) 0.54-0.76; P < 0.0001], ranging from 0.46 to 0.82 for subgroups. Estimated improvement in 3-year DFS in subgroups ranged from +11.3% to +0.6%. Patients with the best prognosis (those with node-negative disease and tumors 1.1-2.0 cm) had benefit similar to the overall cohort (HR 0.53, 95% CI 0.26-1.07; 3-year DFS improvement +4.6%, 95% CI -4.0% to 13.2%). CONCLUSIONS: Adjuvant trastuzumab therapy reduces the risk of relapse similarly across subgroups defined by nodal status and steroid hormone receptor status, even those at relatively low risk for relapse.

Use of pulsed field gel electrophoresis to characterize BCR gene involvement in CML patients lacking M-BCR rearrangement.

We studied the pattern of BCR involvement in 52 patients with chronic myeloid leukemia by Southern blotting. Of 33 Philadelphia (Ph)-positive patients, 30 had evidence of M-BCR rearrangement, two cases were difficult to interpret, and one clearly lacked evidence of M-BCR rearrangement. Of 19 Ph-negative patients, nine showed M-BCR rearrangement, nine showed no rearrangement, and one result was uncertain. We selected for more detailed study eight patients (three Ph-positive and five Ph-negative). Two of the Ph-positive patients, whose Southern blots were difficult to interpret, had rearranged bands when the BCR gene was studied by pulsed field gel electrophoresis (PFGE). Results of PFGE studies and in situ hybridization to metaphase chromosomes in the third Ph-positive patient, whose DNA clearly lacked M-BCR rearrangement on Southern analysis, were consistent with a breakpoint on chromosome 22 located 3' of all known exons of the BCR gene. However, mRNA studied with the polymerase chain reaction showed evidence of a classical b2-a2 linkage. The findings in this patient may be explained by an unusual genomic breakpoint downstream of the BCR gene associated with long range splicing that excluded all of the 3' BCR exons. Of the five patients with Ph-negative M-BCR non-rearranged CML studied by PFGE for BCR gene rearrangement, none had evidence of rearranged bands. We conclude that PFGE is a valuable adjunct to standard molecular techniques for the study of atypical cases of CML. Occasional patients with Ph-positive CML have breakpoints outside M-BCR. The BCR gene is probably not involved in patients with Ph-negative, M-BCR non-rearranged CML.

Interstitial insertion of varying amounts of ABL-containing genetic material into chromosome 22 in Ph-negative CML.

We studied the cells from three selected patients with Ph-chromosome-negative chronic myeloid leukemia (CML) by Southern blotting, polymerase chain reaction, and in situ hybridization of informative probes to metaphase chromosomes. All three patients had rearrangement of M-BCR sequences in the BCR gene and expression of one or other of the mRNA species characteristic of Ph-positive CML. Leukemic metaphases studied after trypsin-Giemsa banding were indistinguishable from normal. The ABL probe localized both to chromosome 9 and 22 in each case. A probe containing 3' M-BCR sequences localized only to chromosome 22, and not to chromosome 9 as would be expected in Ph-positive CML. Two new probes that recognize different polymorphic regions distal to the ABL gene on chromosome 9 in normal subjects localized exclusively to chromosome 9 in two patients and to both chromosomes 9 and 22 in one patient. These results show that Ph-negative CML with BCR rearrangement is associated with insertion of a variable quantity of chromosome 9 derived material into chromosome 22q11; there is no evidence for reciprocal translocation of material from chromosome 22 to chromosome 9.

Ets-1 p27: A novel Ets-1 isoform with dominant-negative effects on the transcriptional properties and the subcellular localization of Ets-1 p51

The transcription factor Ets-1 is implicated in various physiological processes and invasive pathologies. We identified a novel variant of ets-1, ets-1Delta(III-VI), resulting from the alternative splicing of exons III to VI. This variant encodes a 27 kDa isoform, named Ets-1 p27. Ets-1 p27 lacks the threonine-38 residue, the Pointed domain and the transactivation domain, all of which are required for the transactivation of Ets-1 target genes. Both inhibitory domains surrounding the DNA-binding domain are conserved, suggesting that Ets-1 p27, like the full-length Ets-1 p51 isoform, is autoinhibited for DNA binding. We showed that Ets-1 p27 binds DNA in the same way as Ets-1 p51 does and that it acts both at a transcriptional and a subcellular localization level, thereby constituting a dual-acting dominant negative of Ets-1 p51. Ets-1 p27 blocks Ets-1 p51-mediated transactivation of target genes and induces the translocation of Ets-1 p51 from the nucleus to the cytoplasm. Furthermore, Ets-1 p27 overexpression represses the tumor properties of MDA-MB-231 mammary carcinoma cells in correlation with the known implication of Ets-1 in various cellular mechanisms. Thus the dual-acting dominant-negative function of Ets-1 p27 gives to the Ets-1 p27/Ets-1 p51 ratio a determining effect on cell fate.

Negative hormonal control by the androgen DHT and antiestrogen EM-139 on cell cycle kinetics and proliferation in human breast cancer ZR-75-1 cells

info:eu-repo/semantics/submittedForPublication

Stimulation of apolipoprotein D secretion by steroids coincides with inhibition of cell proliferation in human LNCaP prostate cancer cells

Although steroid hormones are known to play a predominant role in the regulation of cell growth in hormone-sensitive cancers, their mechanisms of action, especially their interaction with growth factors and/or growth inhibitors, is poorly understood. We have recently observed that the effects of androgens and estrogens on the expression of the major protein found in human breast gross cystic disease fluid, protein-24, are opposite to their respective action on cell proliferation in human breast cancer cell lines. Somewhat surprisingly, the recent elucidation of the amino acid sequence of this progesterone binding protein reveals that this tumor marker is apolipoprotein D (apo D), a member of a superfamily of lipophilic ligand carrier proteins. The present study was designed to determine whether apo D is secreted by human prostate cancer cells and could thus be a new marker of steroid action in these cancer cells, and whether the sex steroid-induced stimulation of apo D secretion coincides with inhibition of cell proliferation. We took advantage of the biphasic pattern of the effect of steroids on the proliferation of the human prostate cancer LNCaP cell line, which offers the opportunity to discriminate between positive and negative steroid receptor-regulated cell growth processes. A 10-day exposure to low concentrations of dihydrotestosterone and testosterone caused a potent stimulation of LNCaP cell proliferation, whereas incubation with higher concentrations of these androgens led to a progressive decrease in cell proliferation towards basal levels. The biphasic action of androgens was also observed on apo D secretion, the effects on apo D secretion being inversely related to their action on LNCaP cell proliferation. Similar opposite biphasic effects were also observed with 9 other steroids, thus indicating that the stimulation of secretion of this new biochemical marker coincides with inhibition of cell proliferation in LNCaP human prostatic cancer cells.