We describe a semiquantitative RT-PCR protocol optimized in our laboratory to extract RNA from as little as 10,000 cells and to measure the expression levels of several target mRNAs from each sample. This procedure was optimized on the human erythroleukemia cell line TF-1 but was successfully used on primary cells and on different cell lines. We describe the detailed procedure for the analysis of Bcl-2 levels. Aldolase A was used as an internal control to normalize for sample to sample variations in total RNA amounts and for reaction efficiency. As for all quantitative techniques, great care must be taken in all optimization steps: the necessary controls to ensure a rough quantitative (semi-quantitative) analysis are described here, together with an example from a study on the effects of TGF-β1 in TF-1 cells.

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Summary Recent data have demonstrated that the anti-oestrogen tamoxifen (TAM) is able to facilitate apoptosis in cancer cells not expressing oestrogen receptor (ER). In an attempt to identify the biochemical pathway for this phenomenon, we investigated the role of TAM as an oxidative stress agent. In two ER-negative human cancer cell lines, namely T-leukaemic Jurkat and ovarian A2780 cancer cells, we have demonstrated that TAM is able to generate oxidative stress, thereby causing thiol depletion and activation of the transcriptional factor NF-κB. As described for other oxidative agents, TAM was able to induce either cell proliferation or apoptosis depending on the dose. When used at the lowest dose tested (0.1 µM), a slight proliferative effect of TAM was noticed in terms of cell counts and DNA synthesis rate, whereas at higher doses (10 µM) a consistent occurrence of apoptosis was detected. Importantly, the induction of apoptosis by TAM is not linked to down-regulation or functional inactivation by phosphorylation of the antiapoptotic bcl-2 protein.

Ferritin is composed of two subunits, H and L. cDNA's coding for these proteins from human liver (1,2,3), lymphocytes (4) and from the monocyte-like cell line U937 (5) have been cloned and sequenced. Southern blot analysis on total human DNA reveals that there are many DNA segments hybridizing to the apoferritin H and L cDNA probes (1,2,4,6). In view of the tissue heterogeneity of ferritin molecules (7,8), it appeared possible that apoferritin molecules could be coded by a family of genes differentially expressed in various tissues (1,2). In this paper we describe the cloning and sequencing of the gene coding for human apoferritin H. This gene has three introns; the exon sequence is identical to that of cDNA's isolated from human liver, lymphocytes, HeLa cells and endothelial cells. In addition we show that at least 15 intronless pseudogenes exist, with features suggesting that they were originated by reverse transcription and insertion. On the basis of these results we conclude that only one gene is responsible for the synthesis of the majority of apoferritin H mRNA in various tissues examined, and that probably all the other DNA segments hybridizing with apoferritin cDNA are pseudogenes.

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We analyzed the expression and amplification of cyclin D1 and CDK4 genes in ovarian carcinomas. Northern blot analysis revealed overexpression of cyclin D1 in 12 of 65 (18%) ovarian carcinomas while CDK4 was overexpressed in 7 of 48 cases (14%). None of the tumors showed amplification of any of the 2 genes. Overexpression of cyclin D1 and CDK4 transcripts was correlated, suggesting a role of both genes in altered growth control of ovarian cancer cells. Elevated levels of cyclin D1 were significantly associated with a wellmoderately differentiated grade (G1-G2) (p F 0.005). No significant association was found between cyclin D1 expression and estrogen receptor, progesterone and epidermal growth factor receptor content. Cyclin D1 expression does not appear to be associated with clinical outcome in human ovarian cancer, although a longer follow-up period and screening of other molecules involved in the same pathway would be necessary to assess this hypothesis. Int. J. Cancer 74:390-395, 1997.r 1997 Wiley-Liss, Inc.The prognostic characterization of patients with ovarian cancer, which is based on clinico-pathological criteria, is largely inadequate. Fifty percent of the patients, after optimal surgical debulking and a pathologically complete response to primary chemotherapy, will develop a recurrence of the tumor and will die within 2 years. Thus, the development of additional prognostic factors, closely related to tumor cell biology, is essential for identification of patients with a particularly poor prognosis.Attention has recently been focused on genetic alterations of several proto-oncogenes and tumor suppressor genes that mediate signal transduction pathways involved in cell proliferation and differentiation as well as cell cycle control. Cyclins are a family of cell cycle control proteins that regulate cell cycle progression by associating with and activating cyclin-dependent kinases (CDKs). Since the major regulatory events leading to mammalian cell proliferation and differentiation occur in the G 0 to G 1 phases and/or in the G 1 to S phase transition during the cell cycle, the deregulated expression of G 1 or G 1 /S phase cyclins or their related CDKs may cause loss of cell cycle control and thereby contribute to neoplastic transformation. Cyclin D1 is known to regulate cell cycle progression at the G 1 -S checkpoint, and its overexpression shortens the G 1 -S transition. To function as a positive regulator of G 1 progression, cyclin D1 needs to bind to its catalytic subunit, CDK4. When activated by cyclin D1, CDK4 phosphorylates the retinoblastoma tumor suppressor protein (pRb), resulting in release of pRbmediated G 1 arrest. Indeed, the unphosphorylated form of pRb is thought to restrain cell cycle progression by binding and inactivating members of the E2F family of transcription factors, the inhibitory effect being abolished by phosphorylation. The cyclin D1/CDK4 complex can be inhibited by various proteins including some members of the p16 family of cell cycle inhibitors. Amplification and/or overexpre...

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Endoglin (CD105) is a component of the transforming growth factor-beta (TGF-beta) receptor (TGF-betaR) complex. Together with betaglycan, CD105 is considered as a TGF-betaR accessory molecule (also called TGF-betaRIII), but its functions in the receptor-ligand interactions are still poorly understood. A small subset of human CD34+ hematopoietic stem/progenitor cells that has phenotypic and functional features suggestive of very primitive hematopoietic cells expresses the CD105 antigen. CD34+/CD105+ cells recirculate in the peripheral blood of mobilized subjects and can be purified by immunomagnetic isolation strategies. The hematopoietic potential of these CD34+/CD105+ cells appears to be sustained by a combination of hematopoietic and non-hematopoietic cytokines, which comprises Flt3 ligand, erythropoietin, interleukin-15 and vascular endothelial growth factor. Endogenous TGF-beta1 is a crucial factor for the maintenance of CD34+/CD105+ immaturity acting through positive modulation of both CD105 and CD34 molecules in the absence of relevant effects on the cell cycle profile. CD105 is absent on very primitive CD34-/lineage-/CD45+ (CD34-Lin-) human hematopoietic cells isolated from cord blood. However, in vitro exposure of CD34-Lin- cells to exogenous TGF-beta1 causes the appearance of a discrete population of CD34+/CD105+ cells. Collectively, available data on CD105 expression and function in primitive hematopoiesis indicate that this molecule could cooperate with the dissociation of TGF-beta1 cell cycle effects from its other effects on cell survival and differentiation.