Expression of a 65 kDa oncofetal protein in human prostatic carcinoma

The concentration of a novel 65 kDa oncofetal protein, p65, was measured in the sera of patients with prostatic malignancies using an enzyme-linked immunosorbent assay. The prostate cancer sera were positive for p65 in 40 out of 59 cases (68%), while only 7 of 79 normal sera (9%) and 12 of 61 sera from patients with benign diseases (20%) were positive. The detection system had an overall sensitivity of 68% and a specificity of 86%. Elevated p65 levels correlated positively with the pathologic stages of the prostate cancer. Using this marker in concert with PSA may increase our ability to evaluate treatment response and aid in early detection of prostate cancer.     

Induction of an oncofetal marker protein upon X-radiation of rat mammary glands

Fifty-day-old female Sprague--Dawley rats were given carcinogenic and sub-carcinogenic doses of X-radiation to the mammary glands to evaluate the induction of a 60-kDa oncofetal protein (OFP-60). This protein has previously been shown to be produced in the target organ and released to circulation during chemical carcinogenesis and tumorigenesis. In a time course experiment, the mammary glands of the rats were irradiated with a single dose of 1.85 gray (Gy). The OFP-60 marker protein was detected in peripheral blood at 21 days post-irradiation. Irradiation of the mammary gland with single X-ray doses ranging from 0.22 to 1.85 Gy produced a linear relationship between X-ray dose and plasma concentration of OFP-60 determined at 21 days post-treatment. This initiation-related parameter correlates with the known linear relationship between dose of X-radiation and potential tumor incidence.     

Expression of fibroblast growth factor receptors in human leukemia cells.

We have previously cloned from K562 leukemia cells two novel fibroblast growth factor receptors (FGFR-3 and FGFR-4; J. Partanen et al., EMBO J., 10: 1347-1354, 1991). Here we have analyzed the mRNA expression of four different FGFRs, including the two novel genes in human leukemia cell lines. We show FGFR-1, FGFR-3, and FGFR-4 mRNAs in several leukemia cell lines at levels similar to those in solid tumor cell lines. Ligand cross-linking experiments indicate that K562 cells have receptors binding acidic FGF but not basic FGF. Expression of FGFRs in leukemia cells may reflect their presence on normal hematopoietic precursor cells or induction during leukemogenesis or cell culture.     

Expression of estramustine-binding protein in ependymomas and in human and developing rat ependymal cells

Summary The mainstays of primary treatment of ependymoma are aggressive surgery followed by radiotherapy. Although spreading occasionally occurs in the cerebrospinal pathways, chemotherapy is still not established and no ultimate drug has so far been found. Estramustine-phosphate (EMP), with a demonstrated effect on astrocytomain vitro, has been shown to penetrate the blood-tumor barrier and to accumulate in human brain tumor tissue including ependymoma. It has been proposed that the cytotoxic effect of EMP depends on the presence of a binding protein, estramustine-binding protein (EMBP). In the present paper we have, for the first time, immunohistochemically demonstrated an EMBP-like protein in a series of ependymomas. Immunoreactivity was found within the cytoplasm of the tumor cells with a tendency to increase with increasing malignancy of the tumor. In addition, the occurence of EMBP-like protein was demonstrated in human ependymal cells. In the rat brain, a weak immunoreactivity was detected in early fetal neuroepithelial cells while the staining intensity was increased in mature ependymal cells in late fetal, neonatal, and adult rat. Thus, immunoreactivity for an EMBP-like protein was demonstrated in ependymoma tissue, normal human ependyma and in the developing rat ependymal cells.     

Expression of IL-18 and its receptor in human leukemia cells

The importance of IL-18, although clearly established in solid tumors, has not been fully elucidated in human hematopoietic neoplasms. Here we examined the mRNA and protein for IL-18 in eight human hematopoietic cell lines representing different lineages and neoplasms including leukemia, lymphoma and others. Our results revealed that IL-18 mRNA was expressed in these cells and that the corresponding protein was found in the cytoplasm. Seven of eight cell lines were also found to express two subunits of the IL-18 receptor (IL-18R) at varied levels. Furthermore, 29 out of 51 leukemia patients tested were observed to express IL-18R with 18/29 (62%) co-expression of both receptor and ligand. By blocking the IL-18 loop using specific antisense oligodeoxynucleotide (ASON) for IL-18 mRNA or anti-human IL-18R monoclonal antibody (McAbR), we were not able to demonstrate a marked inhibition on the most leukemic cell lines growth. Moreover, the potential proliferation in vitro of primary AML cells co-expressing IL-18 and its receptor was not significantly enhanced by recombinant human IL-18, suggesting that IL-18 is not apparently implicated in the proliferation of the leukemia cells via an autocrine loop. Additionally, we also found the effective modulating effect of M-CSF, IFN-alpha and TNF-alpha on IL-18R expression, implying an important in vivo effect of cytokines on IL-18-induced reaction. Moreover, the modulation of IL-18R expression was possibly irrelevant to IFN-gamma secretion induced by these cytokines.     

Tyrosine protein kinases and their substrates in human leukemia cells

We have quantitated tyrosine protein kinase (TPK) activity in particulate and cytosolic fractions from human leukemia cells. Slowly proliferating cells from patients with chronic lymphocytic leukemia (CLL) had levels of TPK similar to those of quiescent normal lymphocytes. Cells from patients with acute lymphoblastic leukemia (ALL), acute myeloid leukemia (AML) and chronic granulocytic leukemia (CGL) contained markedly lower levels of TPK activity, similar to the levels in phytohaemagglutinin-stimulated (proliferating) normal lymphocytes and in bone marrow cells. This suggested that TPK is part of a mechanism for transducing growth signals and is down-regulated following signal transmission.

We also identified endogenous substrates for TPK in leukemic cells. Particulate fractions from ALL, CLL and AML cells contained substrates identical to those previously detected in normal lymphocytes. In particular, a 38kD substrate thought to be involved in early stages of growth signal transduction in normal lymphocytes was found in all samples of these groups examined. Cytosolic fractions from these groups of leukemia cells contained higher molecular weight substrates not found in resting or proliferating normal lymphocytes or bone marrow cells. In contrast, TPK substrates in both particulate and cytosolic fractions from CGL cells resembled those of normal bone marrow cells in that only proteins with molecular weight below 40kD were labelled on tyrosine.

We conclude that leukemic cells do not contain higher levels of TPK than do normal hemopoietic cells. Qualitative differences in TPK species or in their substrates may result in aberrant regulation of proliferation in leukemic cells. However, we cannot exclude the possibility that additional TPK substrates detected in leukemic cells were a feature of the normal equivalent hematopoietic cells from which the leukemia cells were derived.     

Expression of a unique helios isoform in human leukemia cells

The purpose of the present study was to characterize the human Helios gene products expressed in leukemia cells. A 3.5 kb human Helios cDNA clone was isolated from a human T-cell cDNA library derived from the human T-acute lymphoblastic leukemia (ALL) cell line JURKAT. This cDNA clone had a unique open reading frame (ORF) encoding a novel 304 amino acid (AA) peptide, which was designated as Helios 3. The sequence of the 289 AA C-terminal portion of Helios 3 downstream of V-16 is identical to the corresponding sequence found in Helios 1 and 2 and contains two zinc fingers. By contrast, the 15 AA N-terminal portion of Helios 3 is unique and does not contain the N-terminal zinc finger motifs that are conserved in Helios 1 and 2 as well as other previously identified members of the Ikaros family. Southern blot analysis of genomic DNA fragments of the human Helios gene locus showed that Helios 3 is encoded by the same genomic locus as Helios 1 and 2. The expression of Helios 3 mRNA was not restricted to T-lineage ALL cells or another immunophenotypically distinct subset of leukemias. Helios 3 mRNA was expressed in freshly obtained primary leukemic cells from six of 15 children with newly diagnosed ALL. Helios 3 exhibited a unique protein interaction profile via its N-terminal portion, which may have biological significance in pathogenesis of human leukemias.     

Suppression of proline-directed protein kinase F(A) potentiates apoptotic induction and greatly enhances chemosensitivity in human acute lymphoblastic leukemia cells.

BACKGROUND: Previously, the authors reported that specific antisense suppression of overexpressed proline-directed protein kinase (PDPK) F(A) enhances the chemosensitivity of various clinical anticancer drugs up to > 100-fold in human prostate carcinoma cells, suggesting an association of PDPK F(A) with drug resistance in human malignancies. METHODS: In this report, by using a similar approach, the authors demonstrate further that the suppression of PDPK F(A) enhances even more dramatically the chemosensitivity of clinically used anticancer drugs in various types of human acute lymphoblastic leukemia (ALL) cells. RESULTS: Compared with parental and control transfected cells, transduced ALL cells (both Jurkat and CCRF-CEM cells) with low levels of PDPK F(A) displayed an enhanced sensitivity to vincristine, vinblastine, paclitaxel, methotrexate, doxorubicin, and daunorubicin. Estimation of the 50% inhibitory concentration (IC(50)) index further revealed that the transduced cells displayed up to > 3000-fold drug sensitivity, and there was a correlation between suppressed levels of PDPK F(A) and drug sensitivity. A mechanistic study further revealed that the enhanced chemosensitivity in transduced ALL cells was due mainly to the potentiation of apoptotic induction. CONCLUSIONS: Taken together, the results demonstrate that the suppression of overexpressed PDPK F(A) greatly enhances the chemosensitivity of various clinical anticancer drugs in both types of human ALL cells, providing initial evidence for an important role of this PDPK in controlling multidrug resistance of ALL.     

Cremophor EL inhibits 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced protein phosphorylation in human myeloblastic leukemia ML-1 cells.

Cremophor EL, a polyloxyethylene castor oil derivative used clinically as a parenteral vehicle, inhibits protein kinase c activity in vitro. The tumor promoting agent TPA (12-0-tetradecanoylphorbol-13-acetate) activated protein kinase C and induced phosphorylation of cellular proteins of human myeloblastic leukemia ML-1 cells. Polypeptides of 56 KDa, 44 KDa, 37 KDa, 35 KDa and 31 KDa were particularly phosphorylated in response to TPA activation. However, the phosphorylations of these polypeptides, especially that of 37 KDa, were greatly reduced by treatment of the TPA-activated ML-1 cells with Cremophor EL. Cremophor EL also inhibited the growth of ML-1 cells. On the other hand, the TPA-induced cell differentiation in ML-1, which is considered a separate event from protein kinase C activation, was not affected by Cremophor EL. These studies suggest biological implications for the observed in vitro activity of Cremophor EL. The studies may also provide a mechanism for the Cremophor EL-associated cytotoxicities observed when it is used clinically as a parenteral vehicle.     

Expression of maturation-specific nuclear antigens in differentiating human myeloid leukemia cells

The expression of three myeloid-specific nuclear antigens was studied by indirect immunofluorescence with murine monoclonal antibodies in human myeloid (HL-60, ML-2, KG-1, and B-II) leukemia cells treated with chemical inducers of cell differentiation. Treatment of the promyelocytic HL-60 cells with dimethyl sulfoxide or 1,25-dihydroxyvitamin D3 induced the cells to acquire a phenotype that resembled that of granulocytes and monocytes-macrophages, respectively. These phenotypes were characterized by changes in cell growth, cell morphology, expression of specific cell surface antigens, and activities of lysozyme and nonspecific esterase enzymes. Induction of these differentiation markers in the HL-60 cells was associated with induction of the myeloid-specific nuclear antigens. The ML-2 cells, which are arrested at the myeloblast-promyelocyte stage, were also susceptible to the induction of cell differentiation and to changes in the expression of the nuclear antigens, but the degree of susceptibility was less than in the HL-60 cells. The less-differentiated KG-1 and B-II myeloid cells were either not responsive or responded only in a limited degree to the induction of cell differentiation or to changes in the expression of the nuclear antigens. We suggest that the reactivity of cells with monoclonal antibodies to specific nuclear antigens can be used as a maturational marker in cell differentiation studies. Furthermore, nuclear antigens expressed early in cellular differentiation may provide information about changes in regulatory elements in normal and malignant cells.     

Expression of p66(Shc) protein correlates with proliferation of human prostate cancer cells

p66(Shc), an isoform of Shc adaptor proteins, is shown to mediate various signals, including cellular stress. However, little is known about its involvement in carcinogenesis. We previously showed that p66(Shc) protein level is upregulated by steroid hormones in human carcinoma cells and is higher in prostate cancer (PCa) specimens than adjacent noncancerous cells. In this study, we investigated the role of p66(Shc) protein in PCa cell proliferation. Among different PCa cell lines tested, p66(Shc) protein level showed positive correlation with cell proliferation, that is, rapid-growing cells expressed higher p66(Shc) protein than slow-growing cells. Exposure of slow-growing LNCaP C-33 cells to epidermal growth factor (EGF) and 5alpha-dihydrotestosterone (DHT) led to upregulation of proliferation and p66(Shc) protein level. Conversely, growth suppression of fast-growing cells by cellular form of prostatic acid phosphatase (cPAcP) expression, a negative growth regulator, down-regulated their p66(Shc) protein level. Additionally, increased expression of p66(Shc) protein by cDNA transfection in LNCaP C-33 cells resulted in increased cell proliferation. Cell cycle analyses showed higher percentage of p66(Shc)-overexpressing cells at S phase (24%) than control cells (17%), correlating with their growth rates. On the other hand, transient knock-down of p66(Shc) expression by RNAi in rapidly growing cells decreased their proliferation as evidenced by the reduced cell growth as well as S phase in p66(Shc)-knocked down cells. The p66(Shc) signaling in cell growth regulation is apparently mediated by extracellular signal-regulated kinase/mitogen-activated protein kinase (ERK/MAPK). Thus, our results indicate a novel role for p66(Shc) in prostate carcinogenesis, in part, promoting cell proliferation.     

Effect of tumor promoters on human T cell leukemia/lymphoma virus (HTLV)-structural protein induction in adult T-cell leukemia cells

We assayed the capacity of tumor promoters to induce human T-cell leukemia/lymphoma virus (HTLV) structural proteins p19 and p24 from the HTLV genome-carrying adult T-cell leukemia (ATL) cell lines, MT-1 and KH-2Lo, and fresh ATL cells. Among the tested substances, 12-O-tetradecanoyl phorbol-13-acetate (TPA), 12-hexadecanoyl-phorbol-13-acetate (HPA) and teleocidin induced HTLV structural protein p19 and p24. This suggests that certain environmental substances, especially those known to be tumor promoters, may activate the HTLV-gene in ATL cells.     

Expression of apoptosis-controlling proteins in acute leukemia cells.

The expression of Bcl-2 family proteins (Bcl-2, Bcl-X, Bcl-XL, Bcl-Xs, BAX, BAD, MCL-1) and of Interleukin-1 converting enzyme (ICE)-related proteins (ICE, CPP32, ICH- 1) was analyzed in acute leukemia cells by flow cytometry. Most proteins studied were detectable in cell lines such as KG1a, HL60, K562 (myeloblastic), REH, RAJI and MOLT4 (lymphoblastic) and VAL (B-cell lymphoma). However, BCL-Xs and BAK were weakly expressed in K562, as were Bcl-X, BAD and BAK in the VAL line. In acute myeloid leukemia (66 cases studied), the proteins were expressed in most cases in a high percentage of cells, especially BAX and CPP32, without correlation with hematological characteristics. However, Bcl-2 was expressed in a higher percentage of cells in FAB M1 and M5 cases, and in CD34-positive cases, whereas Bcl-Xs was more frequently expressed in M3 cases. No differences were observed regarding fluorescence intensity. Higher percentages of Bcl-2-positive cells were associated with low remission rate, while expression of Bcl-Xs was predictive of high remission rate. In acute lymphoblastic leukemia (36 cases), all proteins studied were expressed in a majority of cases. Bcl-Xs was more frequently detected in T-cell type, and was also associated with a higher remission rate. These results suggest that apoptosis-controlling proteins may have a role in the pathogenesis and response to therapy of acute leukemia.     

胰腺癌P16蛋白的表达及其临床意义

 应用免疫组织化学LSAB法检测P16蛋白在胰腺癌中的表达。结果显示,47例胰腺癌P16蛋白表达阳性率为55.3％(26/47);其阳性率与患者性别、年龄、肿瘤大小,病理学类型及组织学分级无关;而与胰腺癌临床分期和患者1年生存率明显相关(P<0.05)。表明P16基因缺失或突变在胰腺癌发生发展的后期发挥重要作用;P16蛋白低表达者预后差。因此P16蛋白可作为胰腺癌的分子生物学标志。