A wide variety of virally and spontaneously transformed fibroblasts secrete a major transformation-related phosphoprotein with a molecular weight (MW), depending on the species of origin, of about 62,000 (62K). Markedly elevated extracellular levels of this major 32P-labelled protein are not simply linked to exponential growth but instead are associated directly with transformation. The phosphoprotein is not antigenically related to p60src, p60c-src or simian virus 40 (SV40) non-viral T antigen, and it is further distinguishable from SV40 non-viral T antigen (pp 53) on the basis of its electrophoretic mobility. In this study we have compared a variety of normal and transformed epithelial cells for secretion of this 32P-labelled protein and have found that this marker distinguishes neoplastic from preneoplastic and normal mouse mammary epithelium and also identifies highly tumorigenic cells derived from guinea pig bile duct epithelium and rat liver epithelium. Because the classical phenotypic properties commonly associated with transformation of fibroblasts cannot be generally used to discriminate tumorigenic from non-tumorigenic epithelial cells, this phosphoprotein, which identifies tumorigenic cells of both fibroblastic and epithelial origin, is likely to be of particular importance.

The actin cytoskeleton underlies several normal cellular functions and is deranged during carcinogenesis. Gelsolin, a multifunctional actin-binding protein, is downregulated in several types of tumors and its abnormal expression is one of the most common defects noted in invasive breast carcinoma (ICA). This study utilizes immunohistochemistry to examine the expression of gelsolin in 95 ICA, 59 ductal carcinoma in situ (DCIS) and 36 benign lesions, including 17 atypical ductal hyperplasia (ADH). Cytoplasmic staining was scored as positive, reduced or negative. Gelsolin expression was then correlated with patient's age, tumor size, histologic grade and lymph node status. All unremarkable breast biopsies, 88% of ADH, 44% of DCIS and 28% of ICA were positive for gelsolin. This represents a significant difference among the groups (p = < 0.0001) and the trend towards reduced gelsolin with the progression to ICA is significantly linear (p = < 0.0001). For invasive carcinoma, patients older than 44 years were significantly more likely to have decreased expression of gelsolin than patients 44 years old and younger (p = 0.007). Bivariate analysis showed no correlation of gelsolin expression with lymph node status (p = 0.62), tumor size (p = 0.10), histologic grade (p = 0.42), estrogen receptor status (p = 1.0) or other clinicopathologic parameters. In clinical follow-up, there were 18 breast tumor related deaths within a median follow-up time of 4.2 years. Survival analysis indicated that the level of gelsolin expression may be associated with survival (p = 0.06). In summary, the frequency of gelsolin deficiency increases significantly with progression from ADH to DCIS to ICA. Additionally, gelsolin expression may be an independent marker of prognosis.

No abstract

The majority of the adenocarcinomas arising in Barrett esophagus manifest clinically at an advanced stage and have a poor prognosis. As a result of this poor prognosis, much attention has been directed toward the exploration of markers for neoplastic progression in Barrett esophagus. The objective of the present study was to determine the expression of beta-catenin by immunohistochemical analysis in 70 adenocarcinomas developed in Barrett esophagus and to examine its relationship to various prognostic factors currently in use. Abnormal beta-catenin expression, consisting of the loss of membranous staining and the appearance of the nuclear staining, was found in 43 cases (61%). Of patients with the 43 tumors showing abnormal beta-catenin expression, 25 (58%) survived more than 1 year. In contrast, only 7 (26%) of 27 patients with tumors showing normal beta-catenin expression survived longer than 1 year. Most of the superficial (Tis-T1) tumors (83% [10/12]) exhibited abnormal beta-catenin expression compared with only 53% (31/58) in the T2-T3 group. These results suggest a possible correlation among beta-catenin expression, tumor stage, and length of survival as prognostic factors in patients with adenocarcinoma in Barrett esophagus.

The related members of the interleukin-6 (IL-6) family of cytokines, leukemia inhibitory factor (LIF), oncostatin M (OSM) and IL-6 are inflammatory mediators that control differentiated cell functions as well as proliferation. The cellular responsiveness to these cytokines is largely determined by the expression of the appropriate receptor proteins. The receptor expression profile for each cell type is established during differentiation and is often altered during oncogenic transformation. Since inhibition of histone deacetylases (HDAC) has the potential to re-activate epigenetically silenced genes, we asked whether inhibition of HDAC enhances the expression of IL-6 cytokine receptors and, thus, increase desirable cytokine responses. We demonstrate that treatment with FR901228 (FR), an HDAC inhibitor, increases the responsiveness to LIF in different cell types, including normal fibroblasts, epithelial cells, macrophages and splenocytes, as well as various tumor cell lines. Depending on the cell type, FR treatment also enhances the responsiveness to OSM and IL-6. These effects involve a transcriptional induction of the cytokine receptor subunits LIFRa, OSMRb, gp130, or the transcription factor STAT3. FR-specific induction of LIFRa occurs independently of de novo protein synthesis and cell proliferation and is mediated in part by the CBP/p300 coactivator. Chromatin immunoprecipitation experiments indicate that the expression of LIFRa and gp130 genes correlates with the level of acetylated histone 3 associated with the receptor promoter regions. The FR-stimulated expression of IL-6-type cytokine receptors in certain tumor cells also provided improved conditions for suppression of cell growth by taking advantage of the growth inhibitory effect of these cytokines.

No abstract

Abstract. The sequence of heat shock-induced perturbations in protein synthesis and cytoskeletal organization was investigated in primary cultures of mouse mammary epithelial cells (MMEC). Exposure of the cells to 45°C for 15 min caused a marked inhibition of protein synthesis through 2 h after heat. Resumption of protein synthesis began by 4 h, was complete by 8 h, and was accompanied by induction of four major heat shock proteins (HSPs) of 68, 70, 89, and 110 kD. Fluorescent cytochemistry studies indicated that heat shock elicited a reversible change in the organization of keratin filaments (KFs) and actin filaments but had a negligible effect on microtubules. Changes in the organization of KFs progressed gradually with maximal retraction and collapse into the perinuclear zone occurring at 1-2 h after heat followed by restoration to the fully extended state at 8 h. In contrast, actin illaments disappeared immediately after heat treatment and then rapidly returned within 30-60 min to their original appearance. The translocation of many organelles first into and then away from the juxtanuclear area along with the disruption and reformation of polyribosomes were concurrent with the sequential changes in distribution of KFs. The recovery of the arrangement of KFs coincided with but was independent of the resumption of protein synthesis and induction of HSPs. Thermotolerance could be induced in protein synthesis and KFs, but not in actin filaments, by a conditioning heat treatment. Neither protein synthesis nor induction of HSPs was necessary for the acquisition of thermotolerance in the KFs. The results are compatible with the possibility that protein synthesis may depend on the integrity of the KF network in MMEC. Heat shock thus can efficiently disarrange the KF system in a large population of epithelial cells, thereby facilitating studies on the functions of this cytoskeletal component.T HE effects of temperature elevation on cellular physiology have been studied in widely divergent organisms from bacteria to man (58). The dramatic changes in gene programming characterized by the induction of a specific set of proteins, usually referred to as heat shock proteins (HSPs),t together with inhibition in the synthesis of most other cellular proteins have been recognized as the main features of the heat shock response (43,51,61). This response is thought, at the simplest level, to be homeostatic to protect the cell against the environmental insult and provide it with the capacity to survive the crisis and preserve normal cellular activities. However, the molecular mechanisms responsible for these modifications remain obscure.Along with the rapid and transient reprogramming of transcription and translation, alterations in cellular morphology

Expression of gelsolin, an actin filament regulatory protein, in human breast ductal carcinoma in situ (DCIS) was analyzed by immunohistochemistry using a monoclonal antibody. Formalin-fixed paraffin-embedded tissues from 59 pure DCIS specimens and 33 DCIS specimens with associated invasive components were evaluated for gelsolin reactivity and compared to eight normal breast cases and 76 invasive breast cancers. The proportion of cases exhibiting negative/low expression of gelsolin in the epithelium was as follows -- normal, 0%; pure DCIS, 56%; DCIS associated with invasion, 58% in the DCIS component and 66% in the invasive component; invasive carcinoma, 70%. These data demonstrate that down-regulation of gelsolin expression in breast epithelium frequently parallels progression to malignancy. Testing gelsolin expression (normal vs. negative/low levels) in the DCIS lesions for associations with patient age or any of the following histopathologic parameters revealed no significant (95% probability level) correlations -- tumor size; pathologic (Van Nuys system) grade; nuclear grade; necrosis; presence of histologic calcifications; presence or type of adjacent benign lesions; architectural histologic pattern; and mammographic extent. Gelsolin loss was more commonly associated with mammographic soft tissue lesions as compared to calcified lesions (P = 0.009). A positive trend of borderline significance (P = 0.06) found in the DCIS with invasion group was a correlation between down-regulated gelsolin expression in the DCIS component and size (< versus > or = 15 mm) of the invasive tumor. In conclusion, reduced gelsolin protein is detectable in at least half of breast lesions which have progressed to DCIS. The trend between increasing gelsolin loss and malignant progression from normal epithelium to DCIS to invasive breast cancer (P < 0.0001) suggests additional investigation is needed to determine the potential of altered gelsolin expression as a marker for prognosis and for therapeutic interventions in breast cancer.