Immunohistochemical versus molecular detection of RAK antigens in breast cancer.

RAK antigens p120, p42, and p25 exhibit molecular and immunological similarity to the proteins encoded by HIV-1 and are expressed by 95% of breast and gynecological cancer cases in women and prostate cancer cases in men. Binding of the monoclonal antibody (MAb) RAK-BrI to cancer RAK antigens has been found to be inhibited by a peptide derived from the variable loop V3 of HIV-1. Since MAb RAK-BrI has been developed against denatured froms of breast cancer proteins, and it binds to a short epitope, GRAF, this MAb does not recognize the native, three-dimensional structure of proteins.

Relevance of the viral RAK alpha gene in diagnosis of malignant versus nonmalignant tumors of the ovary and uterus.

Human immunodeficiency virus type 1 (HIV-1)-like antigens RAK (named after the inventor E. M. Rakowicz) p120, p42, and p25, as well as HIV-1-like segments of cancer DNA (RAK gene alpha), have been found before in breast and prostate cancers.

Giant syncytia and virus-like particles in ovarian carcinoma cells isolated from ascites fluid.

Ovarian cancer cells were isolated from ascites fluid of 30 different patients diagnosed with cystadenocarcinoma of ovaries. Large colonies of malignant ASC cells were observed during the first week of cell growth in vitro. Colony formation was followed by fusion of cells and formation of large multinucleated and highly vacuolated syncytia.

Human immunodeficiency virus type 1-like DNA sequences and immunoreactive viral particles with unique association with breast cancer.

RAK antigens p120, p42, and p25 exhibit molecular and immunological similarity to the proteins encoded by human immunodeficiency virus type 1 (HIV-1) and are expressed by 95% of breast and gynecological cancer cases in women and prostate cancer cases in men. The binding of an epitope-specific anti-HIV-1 gp120 monoclonal antibody (MAb) (amino acids 308 to 322) to cancer RAK antigens has been found to be inhibited by a peptide derived from variable loop V3 of HIV-1. Breast cancer DNAs of 40 patients were PCR amplified with HIV-1 gp41-derived primers, and all of the samples were found to be positive.

Prostate, breast and gynecological cancer markers RAK with homology to HIV-1.

Breast and gynecological cancer-associated antigens RAK p120, p42 and p25 exhibit molecular, immunological and genetic homology to HIV-1 proteins. Normal tissues, including the majority of tissues adjacent to cancer, do not express these unique cancer markers. Antigens RAK are now detected in 100% of prostate cancer and in the majority of prostate benign hyperplasia (BPH) cases.

New protein and PCR markers RAK for diagnosis, prognosis and surgery guidance for breast cancer.

Breast cancer antigens RAK-p120, -p42, -p25 were detected in 100% of breast cancer cases tested (71 cases). Only 10% of adjacent tissue cases tested positive for all three cancer antigens, and 17.5% of the cases tested positive for two antigens only.

Diagnostic evaluation of cancer antigens RAK .1. Cervical and ovarian cancer.

Cancer antigens RAK-p120, p42, and p25, which exhibit biological, immunological and molecular similarity to the proteins expressed by Human Immunodeficiency Virus 1 (HIV-1), were found in 47 of 47 tested cases of serous adenocarcinoma of the ovary, and 45 of 45 tested cases of squamous carcinoma of the cervix. Normal ovary and cervix did not express antigens RAK. High molecular weight protein (RAK-p160) was detected in the blood of over 61% of ovarian and 72% of cervical cancer patients, and in 14.

PDGF AA as mediator in nicotine-dependent carcinogenesis.

Effect of nicotine on PDGF AA and PDGF BB interaction with cervical cancer SiHa cells was tested. [125I]PDGF AA was internalized by cells and accumulated in the cytoplasm and nucleus (chromatin). In the absence of nicotine, maximal accumulation of [125I]PDGF AA inside the cells occurred after 1 day of incubation, which was followed by a progressive degradation of the growth factor during the next 2, 3 and 5 days of cell exposure.

Inhibition of cancer cell growth by internalized immuno-histone conjugates.

MAb NS 88 directed against breast cancer cells, which is internalized and translocated to the cell nucleus, was conjugated with histone and labeled with 125I. 125I-MAb-histone complexes (M(r) 250,000) were internalized by breast and cervical cancer cells and localized in the cytoplasm and chromatin. Electrophoretic analysis of the cells extracted from the conjugates revealed the same molecular weights of the cytoplasmic and chromatin complexes as those of the native conjugate.

Immunodetection of squamous cell carcinoma-associated variant of nuclear protein.

A new monoclonal antibody, MAb C63.3, was developed by immunizing mice with the high molecular weight fraction of the cytoplasmic proteins from the cervical squamous cell carcinoma. In Western blotting, MAb C63.

Growth factor-mediated mechanisms of nicotine-dependent carcinogenesis.

The direct effect of nicotine on the expression of receptors for the tumor necrosis factor alpha (TNF alpha) and transforming growth factor beta (TGF beta) and the internalization, intracellular distribution and stability of these growth factors in cervical cancer cell line SiHa was studied. Nicotine at concentrations in the range 0.05-0.

Novel family of gynecologic cancer antigens detected by anti-HIV antibody.

Objective: The reactivity of gynecologic cancer proteins with monoclonal antibody (MAb) directed against the human immunodeficiency virus I (HIV-I) was tested.

Methods: Cytoplasmic and nuclear proteins, extracted from a broad range of gynecologic cancers obtained during standard surgical procedures, were tested in Western blotting with MAb 5023 developed against the amino acid sequences 308-322 of the envelope protein gp120 of HIV-I.

Results: Three cell membrane proteins, M(r)l20,000 (p120), M(r)41,000 (p41), and M(r)24,000 (p24), and one chromatin protein, M(r)24,000 (p24), were detected by MAb 5023 in invasive, poorly differentiated cervical squamous-cell carcinoma; ovarian serous cystadenocarcinoma; poorly and well-differentiated endometrial carcinoma; vulvar squamous-cell carcinoma; and malignant mixed müllerian tumor.

Identification of the cell surface and nuclear receptors for NGF in a breast carcinoma cell line.

125I-nerve growth factor (NGF) was found to be internalized and translocated to the nucleus of SKBr5 breast carcinoma cells. The cytoplasm and chromatin isolated from nonmitotic cells accumulated two- and five-fold, respectively, more of 125I-NGF than the cells undergoing mitosis. MAb 20.

Nuclear translocation of monoclonal antibody directed against cell-surface carbohydrate Y determinant.

Monoclonal antibody (MAb) Br 15-6A directed against the carbohydrate Y determinant expressed on tumor cells was found to be internalized and translocated to the nucleus of SK Br 5 breast carcinoma and SW 1116 and SW 707 colorectal carcinoma cells. Intracellular localization of MAb Br 15-6A was determined by cell fraction and by indirect immunofluorescence staining. Internalization of MAb Br 15-6A seems to be mediated by a specific cell surface protein of M(r) 108,000 in colorectal carcinoma cells and M(r) 92,000-96,000 in breast carcinoma cells.

Gamma-interferon-induced nerve growth factor receptors in colorectal carcinoma cell lines.

Gamma-interferon (gamma IFN) was found to induce expression of the 150,000 M(r) cell surface and the 35,000 M(r) chromatin receptors for nerve growth factor (NGF) in the SW1116 colorectal carcinoma cell line that does not express NGF receptors. In the SW707 colorectal carcinoma cell line that expresses a low level of NGF receptors, gamma IFN stimulated expression of the cell surface and the nuclear receptors. Induction of NGF receptors in SW1116 cells resulted in internalization and nuclear translocation of 125I-NGF.

Nerve growth factor chromatin receptor and cell surface receptor-regulated growth of melanocytes and nevus cells.

RNA synthesis in melanocytes and nevus cells, and the proliferation of those cells in the presence of nerve growth factor (NGF) and 12-0-tetradecanoyl-phorbol-13-acetate (TPA), were found to correlate with the amount of NGF bound to the chromatin versus the total internalized NGF (n/c NGF = nuclear/cellular ration). In nevus cells and in melanocytes of the early passages (n/c NGF = 0.16-0.

Chromatin and cell surface receptors mediate melanoma cell growth response to nerve growth factor.

Growth response to nerve growth factor (NGF) was tested in the primary melanoma cell line WM 164, which expressed a low level of NGF cell-surface receptor, and in WM 164 cells transfected with cDNA for the cell-surface receptor (TrWM 164 cells), which expressed a higher level of the cell-surface receptor. Neither cell line expressed the chromatin receptor for NGF or internalized NGF. Both cell lines were stimulated to growth by NGF.

Plasma membrane-mediated nuclear uptake and chromatin binding of insulin in tumor cell lines.

Analysis of different cellular fractions after incubation of SW 948 and SW 707 colorectal carcinoma cells or WM 266-4 melanoma cells with 125I-insulin revealed the nondegraded hormone in the chromatin of these cells. Nuclear 125I-insulin was bound to specific fragments of EcoRI-, HaeIII-, and HincII-digested chromatin. A 45-kDa chromatin protein species that binds 125I-insulin was identified.

Expression of A-type PDGF receptor in cytoplasm of tumor cell lines synthesizing PDGF.

Two tumor cell lines, WM 266-4 melanoma and SW 707 colorectal carcinoma, both of which synthesize platelet-derived growth factor (PDGF) but do not express cell surface PDGF receptor, were tested for the presence of intracytoplasmic PDGF receptor. Using a novel method of intracytoplasmic (newly synthesized), receptor precipitation by the growth factor, we identified a 125,000 molecular weight protein crosslinked with 125I-labeled PDGF in a 140,000 molecular weight complex. In vitro translation of the corresponding mRNA revealed a 125,000 molecular weight product which presumably represents the A-type PDGF receptor.

Antagonistic effect of PDGF and NGF on transcription of ribosomal DNA and tumor cell proliferation.

The molecular mechanism by which NGF and PDGF affect growth of tumor cells was tested in human melanoma WM 266-4 and colorectal carcinoma SW 707 cell lines. We present evidence that NGF translocated to the nucleus and bound to the chromatin of SW 707 cells, which express the cell surface and the chromatin receptor for NGF, inhibits ribosomal RNA synthesis which in consequence leads to inhibition of cell proliferation. In WM 266-4 cells, which do not express NGF receptor, NGF does not affect cell proliferation.

Nuclear uptake of monoclonal antibody to a surface glycoprotein and its effect on transcription.

Nuclear transport and chromatin binding of monoclonal antibody (MAb) ME491, directed against a cell surface glycoprotein, was tested in intact cells and in a cell-free system. After a 24-h incubation with 125I-MAb ME491, the chromatin of melanoma cells and of colorectal carcinoma cells contained approximately 10 and 20%, respectively, of the antibody in nondegraded form. 125I-MAb ME491 was bound to a 55-kDa chromatin protein and localized in two HincII-digested chromatin fragments.

Epidermal growth factor (EGF) and monoclonal antibody to cell surface EGF receptor bind to the same chromatin receptor.

Cellular uptake, nuclear translocation, and chromatin binding of epidermal growth factor (EGF) and monoclonal antibodies (MAbs) against the protein domain of the EGF surface receptor (MAb 425) and against the carbohydrate Y determinant on the EGF receptor (MAb Br 15-6A) were analyzed in cell lines that express surface EGF receptor. Both EGF and MAb 425 were translocated to the nucleus and bound in nondegraded form to the chromatin of all cells tested. MAb Br 15-6A was taken up only by SW 948 colorectal carcinoma cells which express EGF receptor whereas neither EGF nor MAb 425 was taken up by SW 707 colorectal carcinoma cells which do not express EGF receptor.

Rapid and sensitive method to detect expression of growth factor receptors.

A sensitive method to analyze growth factor receptor expression is described that is based on precipitation of the receptor by the growth factor. The precipitate that forms after incubation of pure, membrane-free cytoplasm with the growth factor contains both the receptor and the corresponding mRNA. With this method, nerve growth factor (NGF), epidermal growth factor (EGF) and platelet-derived growth factor (PDGF) receptors were detected in several tumor cell lines thought previously to be receptor-negative.

Intracellular receptor binding and nuclear transport of nerve growth factor in intact cells and a cell-free system.

Nuclear uptake of 125I-labeled nerve growth factor (NGF) by cells that either express or do not express the cell surface receptor was tested using intact cells and a cell-free system. Intracellular and consequently nuclear uptake of NGF in intact cells was dependent on the presence of surface NGF receptor, whereas nuclear uptake in a cell-free system did not correlate with cell surface receptor expression. In the cell-free system, nuclear transport was inhibited when NGF receptor was being actively synthesized.

Nerve growth factor receptors in chromatin of melanoma cells, proliferating melanocytes, and colorectal carcinoma cells in vitro.

Nuclear localization of nerve growth factor (NGF) in HS 294 melanoma cells and SW 707 colorectal carcinoma was determined by indirect immunofluorescence staining and by cell fractionation. NGF receptors were immunoprecipitated from the EcoRI-digested chromatin of HS 294 melanoma cells, of melanocytes proliferating in the presence of 12-O-tetradecanoylphorbol-13-acetate, and of SW 707 colorectal carcinoma cells, using a monoclonal antibody to the Mr 75,000 cell surface NGF receptor. Melanoma cells expressed a receptor species with a molecular weight of 230,000.