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Huang RP, Fan Y, Hossain MZ, Peng A, Zeng ZL, Boynton AL. Reversion of the neoplastic phenotype of human glioblastoma cells by connexin 43 (cx43). Cancer Res 1998; 58:5089-96. [PMID: 9823317] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
Connexins (cx), structural components of gap junction, are believed to play a role in the regulation of cell proliferation and suppression of the neoplastic phenotype. We used human brain glioblastoma tumor cells as a model system to test this hypothesis. Western blot and reverse transcription-PCR analysis indicate that the expression levels of the gap junction protein connexin 43 (cx43) are profoundly decreased in several human brain tumor cell lines examined. Transfection of human cx43 into human glioblastoma cell lines U251 and T98G profoundly reduces cell proliferation in monolayer culture, in soft agar, and in athymic nude mice. Surprisingly, these effects are not associated with the establishment of gap junction communication in cx43 transfected cells. We conclude that the loss of cx43 expression may play a role in the development of human gliomas and that cx43 acts as a tumor suppressor gene to human glioblastoma.
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Sehgal A, Keener C, Boynton AL, Warrick J, Murphy GP. CXCR-4, a chemokine receptor, is overexpressed in and required for proliferation of glioblastoma tumor cells. J Surg Oncol 1998; 69:99-104. [PMID: 9808513 DOI: 10.1002/(sici)1096-9098(199810)69:2<99::aid-jso10>3.0.co;2-m] [Citation(s) in RCA: 103] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
BACKGROUND AND OBJECTIVES Using the technique of differential hybridization of Atlas Human cDNA expression arrays, we previously reported the isolation of a G protein coupled receptor, CXCR-4, which is overexpressed in glioblastoma multiforme tumor tissue (GMTT) compared to normal brain tissue (NBT). METHODS Using gene specific reverse transcriptase-polymerase chain reaction (RT-PCR) and in situ hybridization, we studied its expression in a variety of brain and breast tumor tissue samples. To demonstrate the requirement of CXCR-4 in glioblastoma cell proliferation an antisense construct was overexpressed. Glioblastoma cells were also treated with antibodies against CXCR-4 and its ligand, SDFbeta-1. RESULTS Expression analysis indicated that CXCR-4 is overexpressed in 57% of the primary glioblastoma tissues and in 88% of the glioblastoma cell lines analyzed. Overexpression of CXCR-4 in glioblastoma cell lines enhanced their soft agar colony-forming capability. Expression of anti-sense CXCR-4 in glioblastoma cell lines caused neurite outgrowth and cellular differentiation. Treatment of glioblastoma cell lines with CXCR-4 and SDFbeta-1 specific antibodies caused inhibition of glioblastoma cell proliferation. CONCLUSIONS On the basis of these results, we conclude that CXCR-4 gene is required for the proliferation of human glioblastoma tumors.
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Huang RP, Fan Y, Peng A, Zeng ZL, Reed JC, Adamson ED, Boynton AL. Suppression of human fibrosarcoma cell growth by transcription factor, Egr-1, involves down-regulation of Bcl-2. Int J Cancer 1998. [PMID: 9714058 DOI: 10.1002/(sici)1097-0215(19980911)77:6<880::aid-ijc14>3.0.co;2-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Previously, we showed that the transcription factor Egr-1 suppressed the proliferation of v-sis transformed NIH3T3 cells and also a number of human tumor cells. Here, we investigate the possible mechanisms responsible for this function. We show that transfected Egr-1 in human fibrosarcoma cells HT1080 leads to down-regulation of Bcl-2. Transient CAT transfection assays reveal that expression of Egr-1 suppresses Bcl-2 promoter activity in a dose-dependent manner. Furthermore, overexpression of Bcl-2 in Egr-1-expressing HT1080 cells enhanced cell proliferation in monolayer culture and increased anchorage-independent growth. Our results suggest that suppression of tumor cell proliferation by Egr-1 may be at least partially mediated through the down-regulation of Bcl-2.
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Huang RP, Fan Y, Peng A, Zeng ZL, Reed JC, Adamson ED, Boynton AL. Suppression of human fibrosarcoma cell growth by transcription factor, Egr-1, involves down-regulation of Bcl-2. Int J Cancer 1998; 77:880-6. [PMID: 9714058 DOI: 10.1002/(sici)1097-0215(19980911)77:6<880::aid-ijc14>3.0.co;2-5] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Previously, we showed that the transcription factor Egr-1 suppressed the proliferation of v-sis transformed NIH3T3 cells and also a number of human tumor cells. Here, we investigate the possible mechanisms responsible for this function. We show that transfected Egr-1 in human fibrosarcoma cells HT1080 leads to down-regulation of Bcl-2. Transient CAT transfection assays reveal that expression of Egr-1 suppresses Bcl-2 promoter activity in a dose-dependent manner. Furthermore, overexpression of Bcl-2 in Egr-1-expressing HT1080 cells enhanced cell proliferation in monolayer culture and increased anchorage-independent growth. Our results suggest that suppression of tumor cell proliferation by Egr-1 may be at least partially mediated through the down-regulation of Bcl-2.
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Barren RJ, Holmes EH, Boynton AL, Gregorakis A, Elgamal AA, Cobb OE, Wilson CL, Ragde H, Murphy GP. Method for identifying prostate cells in semen using flow cytometry. Prostate 1998; 36:181-8. [PMID: 9687990 DOI: 10.1002/(sici)1097-0045(19980801)36:3<181::aid-pros6>3.0.co;2-k] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
BACKGROUND Prostate-specific antigen (PSA) cannot differentiate benign prostatic hyperplasia (BPH), from prostatitis, or prostate cancer in the range of 4.0-10 ng/ml. An accurate cytologic or histologic assessment is necessary to confirm the proper diagnosis. The nature of a biopsy tends to make it a selective test not frequently repeated. We are reporting a technique employing semen as a source for the differential diagnosis of prostate epithelial cells. METHODS Eleven vasectomized and nonvasectomized prostate cancer patients provided semen samples (stage T1 to T2). Two patients provided repeat samples. In addition, 15 vasectomized or nonvasectomized individuals without evidence of disease provided semen samples. Three million cells fixed with 50% ethanol were stained by an antibody (7E11.C5) to prostate-specific membrane antigen (PSMA), Hybritech Antibody (399) to PSA, and cytokeratin 8 and 18. In addition to the antibodies described, a DNA stain To-Pro 3 was used to identify 2n-4n DNA containing cells. A dual laser, Becton Dickinson FACSCaliber cytometer, was used to analyze the samples. RESULTS All semen specimens contained diploid, cytokeratin 18-positive epithelial cells regardless of disease status. A clear difference between prostate cancer and normal prostate cell samples was observed using staining with 7E11.C5. The ratio of prostatic cells in the total epithelial cell population (PSMA:cytokeratin ratios) was calculated for each specimen. A retrospective study of sixteen semen samples from 11 prostate cancer patients had a mean PSMA:cytokeratin ratio of 0.57, whereas the samples from 15 patients without evidence of cancer had a mean PSMA:cytokeratin ratio of 0.11. This difference was significant. PSA staining was variable and inconsistent. CONCLUSIONS This report demonstrates that human semen contains prostate cells that can be characterized and used in the clinical diagnosis of prostate cancer.
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Hossain MZ, Ao P, Boynton AL. Platelet-derived growth factor-induced disruption of gap junctional communication and phosphorylation of connexin43 involves protein kinase C and mitogen-activated protein kinase. J Cell Physiol 1998; 176:332-41. [PMID: 9648920 DOI: 10.1002/(sici)1097-4652(199808)176:2<332::aid-jcp11>3.0.co;2-5] [Citation(s) in RCA: 67] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Previously we showed a rapid and transient inhibition of gap junctional communication (GJC) by platelet-derived growth factor (PDGF) in T51B rat liver epithelial cells expressing wild-type platelet-derived growth factor beta receptors (PDGFrbeta). This action of PDGF correlated with the hyperphosphorylation of the gap junction protein connexin43 (Cx43) and required PDGFrbeta tyrosine kinase activity, suggesting the participation of protein kinases and phosphatases many of which are activated by PDGF treatment. In the present study, two such kinases, namely protein kinase C (PKC) and mitogen-activated protein kinase (MAPK), are investigated for their possible involvement in PDGF-induced closure of junctional channels and Cx43-phosphorylation. Down-regulation of PKC-isoforms by 12-O-tetradecanoylphorbol-13-acetate or pretreatment with the PKC inhibitor calphostin C, completely blocked PDGF action on GJC and Cx43. Activation of MAPK correlated with PDGF-induced Cx43 phosphorylation, and prevention of MAPK activation by PD98059 eliminated the PDGF effects. Interestingly, elimination of GJC recovery by cycloheximide was associated with a sustained activated-MAPK level. Based on these results we postulate that the activation of PKC and MAPK are required in PDGF-mediated Cx43 phosphorylation and junctional closure.
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Tjoa BA, Simmons SJ, Bowes VA, Ragde H, Rogers M, Elgamal A, Kenny GM, Cobb OE, Ireton RC, Troychak MJ, Salgaller ML, Boynton AL, Murphy GP. Evaluation of phase I/II clinical trials in prostate cancer with dendritic cells and PSMA peptides. Prostate 1998; 36:39-44. [PMID: 9650914 DOI: 10.1002/(sici)1097-0045(19980615)36:1<39::aid-pros6>3.0.co;2-6] [Citation(s) in RCA: 164] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
BACKGROUND A phase I trial involving patients with advanced prostate cancer was conducted to assess the safe administration of dendritic cells (DC) and HLA-A0201-specific prostate-specific membrane antigen (PSMA) peptides (PSM-P1 or -P2). Thirty-three of the phase I participants were subsequently enrolled in a phase II trial, which involved six infusions of DC pulsed with PSM-P1 and -P2 peptides. METHODS Clinical monitoring was conducted up to 770 days from the start of the phase I study. Data collected included: complete blood count, bone and total alkaline phosphatase, prostate markers, physical examination, performance status, bone scan, ProstaScint scan, and chest X-ray, as well as assays to monitor cellular immune responses. RESULTS Nine partial responders were identified in the phase II study based on National Prostate Cancer Project (NPCP) criteria, plus 50% reduction of prostate-specific antigen. Four of the partial responders were also responders in the phase I study, with an average response duration of 225 days. Their combined average total response period was over 370 days. Five other responders were nonresponders in the phase I study. Their average partial response period was 196 days. CONCLUSIONS The responses observed in the phase I and II clinical trials were significant and of long duration. The partial-responder group included patients who continued to respond from phase I, as well as those who started to respond during the phase II trial.
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Sehgal A, Boynton AL, Young RF, Vermeulen SS, Yonemura KS, Kohler EP, Aldape HC, Simrell CR, Murphy GP. Cell adhesion molecule Nr-CAM is over-expressed in human brain tumors. Int J Cancer 1998; 76:451-8. [PMID: 9590116 DOI: 10.1002/(sici)1097-0215(19980518)76:4<451::aid-ijc1>3.0.co;2-q] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Using the technique of differential display-polymerase chain reaction (DD-PCR), we isolated a cDNA fragment that is over-expressed in glioblastoma multiforme tissue as compared to normal brain tissue. Sequence analysis indicated that this sequence is identical to the previously isolated human neuron-glia-related cell adhesion molecule hNr-CAM. Gene-specific RT-PCR analysis indicated that hNr-CAM is over-expressed in high-grade astrocytomas, gliomas and glioblastoma tumor tissues as compared to normal brain tissue. High levels of hNr-CAM expression also were observed in cell lines derived from astrocytomas, gliomas and glioblastoma multiforme tumors. Low levels of hNr-CAM expression were observed in neuroblastoma, meningiomas, melanoma, normal breast and prostate tumor tissues. Northern blot analysis showed an alternatively spliced mRNA of 1.4 kb in several tumors as compared to the 7.5 kb transcript found in normal brain tissue. Genomic Southern blot analysis of DNA from 3 brain tumor cell lines showed that over-expression of hNr-CAM in brain tumors was not due to gene amplification. In situ hybridization analysis indicated that 11 of the 20 human brain tumor samples studied showed hNr-CAM over-expression. Our results suggest that hNr-CAM is over-expressed in malignant brain tumors and can serve as a novel marker for brain tumor detection and perhaps therapy.
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Murphy GP, Kenny GM, Ragde H, Wolfert RL, Boynton AL, Holmes EH, Misrock SL, Bartsch G, Klocker H, Pointner J, Reissigl A, McLeod DG, Douglas T, Morgan T, Gilbaugh J. Measurement of serum prostate-specific membrane antigen, a new prognostic marker for prostate cancer. Urology 1998; 51:89-97. [PMID: 9610563 DOI: 10.1016/s0090-4295(98)00082-x] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
OBJECTIVES To describe current results with Western blot assay for prostate specific membrane antigen (PSMA) using 7E11.C5 antibody and the development of an additional antibody measurement for PSMA by a new sandwich immunoassay. METHODS A population of patients from a screening group, from a difficult diagnostic group, from a pre- and postoperative radical prostatectomy group, and from a group with metastatic disease followed for a serial period, provided the serum values for a prospective assessment of PSMA by Western blot assay. A new monoclonal antibody was sought, reacting to the C-terminal region of PSMA in order to develop a sandwich radioimmunoassay. RESULTS PSMA values in screened patients correlate with the more advanced stage of the cancers determined. In postprostatectomy patients, the PSMA value corresponds more with preoperative values and with the values of those with a poor clinical course. In difficult diagnostic cases, the PSMA value is increased, specifically in hormone-refractory cases and particularly in those cases judged by other criteria, such as the National Prostatic Cancer Project, to be in clinical progression compared with those judged to be in clinical remission. The level of PSMA value appears to be independent of homogeneous tumor volume and to be more related to that of prior hormone treatment, or to where prostate cancer cells can be documented to be outside the prostate. A new monoclonal antibody, 3F5.4G6, reacts with the extracellular domain of PSMA near the C-terminal region. This is in contrast to the previously measured antibody 7E11.C5, which reacts with an N-terminal epitope. 3F5.4G6 recognizes the same PSMA protein as does 7E11.C5. The epitopes are essentially at opposite ends of the molecule. The 3F5.4G6 antibody reacts with the LNCaP line but not with DU145, or PC3. These two antibodies to PSMA are well suited for use in a new sandwich immunoassay. CONCLUSIONS PSMA provides a prostatic cancer serum test by using Western blot, which suggests a clinical prognostic value not seen with other markers. New antibodies, such as 3F5.4G6, reacting with the extracellular domain of PSMA combined with 7E11.C5, appear to offer an opportunity for a new sandwich immunoassay.
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Salgaller ML, Lodge PA, McLean JG, Tjoa BA, Loftus DJ, Ragde H, Kenny GM, Rogers M, Boynton AL, Murphy GP. Report of immune monitoring of prostate cancer patients undergoing T-cell therapy using dendritic cells pulsed with HLA-A2-specific peptides from prostate-specific membrane antigen (PSMA). Prostate 1998; 35:144-51. [PMID: 9568678 DOI: 10.1002/(sici)1097-0045(19980501)35:2<144::aid-pros8>3.0.co;2-j] [Citation(s) in RCA: 84] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
BACKGROUND In this paper we describe our program for the immune monitoring of phase II participants given dendritic cell (DC)/prostate-specific membrane antigen (PSMA)-based immunotherapy, and we also present some initial findings. METHODS Phase II subjects received six administrations of autologous dendritic cells exogenously pulsed with two peptides derived from PSMA. Prior to the initial infusion, and following each treatment, peripheral blood mononuclear cells (PBMC) were collected for the generation of dendritic cells as well as for comprehensive immune monitoring. RESULTS Thus far, an increase in PSMA-peptide-specific as well as overall cellular reactivity has been observed in several patients receiving DC plus PSM-P1 and -P2, as measured by delayed-type hypersensitivity (DTH) test and enzyme-linked immunosorbant assay (ELISA). CONCLUSIONS Our initial observations using an ELISA and DTH test indicate that we are enhancing cellular immunity in prostate cancer patients following infusion with DC plus PSMA-derived peptides. Several methods are underway to comprehensively monitor both cell-mediated and humoral immune responsiveness, including: determining anti-PSMA serum antibody titers, testing immunogen-restricted responder-cell proliferation and cytotoxicity, assessing aberrations in signal transduction, antigen processing, and presentation, and measuring soluble factors that may promote tumor outgrowth.
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Sehgal A, Boynton AL, Young RF, Vermeulen SS, Yonemura KS, Kohler EP, Aldape HC, Simrell CR, Murphy GP. Application of the differential hybridization of Atlas Human expression arrays technique in the identification of differentially expressed genes in human glioblastoma multiforme tumor tissue. J Surg Oncol 1998; 67:234-41. [PMID: 9579370 DOI: 10.1002/(sici)1096-9098(199804)67:4<234::aid-jso5>3.0.co;2-9] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND OBJECTIVES Several molecular biology techniques are utilized to study changes in gene expression during the genesis of human tumors. Our objective was to identify genes that showed altered expression between normal brain tissue (NBT) and glioblastoma multiforme tumor tissue (GMTT). METHODS The technique of differential hybridization of two Atlas Human cDNA expression array was used. In this technique, dCTP32-labeled complimentary DNA from NBT and GMTT was hybridized to two identical human cDNA expression array membranes containing 588 known genes. RESULTS Autoradiographic analysis showed that of the 588 genes analyzed, 52 are overexpressed in GMTT and 57 in NBT. A gene-specific semiquantitative reverse transcription polymerase chain reaction (RT-PCR) method was used to confirm the expression pattern of seven known genes. RT-PCR results demonstrate that the expression pattern of a majority of genes agreed with the expression pattern observed on expression array. The known tumor suppressor genes retinoblastoma (RB) and p53 showed loss of expression in GMTT compared with NBT. CONCLUSIONS We conclude that the differential hybridization technique of Atlas Human cDNA expression array can be a useful method in identifying genes that are differentially expressed either in NBT or GMTT.
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Hossain MZ, Ao P, Boynton AL. Rapid disruption of gap junctional communication and phosphorylation of connexin43 by platelet-derived growth factor in T51B rat liver epithelial cells expressing platelet-derived growth factor receptor. J Cell Physiol 1998; 174:66-77. [PMID: 9397157 DOI: 10.1002/(sici)1097-4652(199801)174:1<66::aid-jcp8>3.0.co;2-e] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Gap junctional communication (GJC) between contacting cells has been postulated to be involved in the regulation of cell proliferation. This suggestion stems from numerous studies showing modulation of GJC by agents that influence cellular proliferation. Platelet-derived growth factor (PDGF), a strong mitogen, inhibits GJC in many cell types. To understand the molecular nature of the signal transduction pathway responsible for the GJC blockade, T51B rat liver epithelial cells, which lack endogenous PDGF receptor (PDGFr), were infected with a retrovirus containing either wild-type full-length cDNA of human PDGFr beta (Kin+) or a mutant PDGFr beta lacking receptor tyrosine kinase activity (Kin-). PDGF caused a complete but transient interruption of cell communication in Kin+ cells within 15-20 min of addition. This interruption of GJC was not associated with a gross destabilization of gap junction plaques but with the phosphorylation of connexin43 (Cx43), the only known gap junction protein expressed in these cells. These effects were exhibited in either control T51B cells or in Kin- cells, indicating a requirement of the receptor tyrosine kinase activity. Further examination revealed that the newly phosphorylated Cx43 then undergoes a rapid degradation utilizing the lysosomal pathway resulting in a decreased total Cx43 protein level. The re-establishment of GJC following PDGF treatment was dependent on protein synthesis. This report describes a suitable cell system which is currently being utilized for the characterization of the PDGF signaling pathway responsible for the inhibition of GJC.
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Hossain MZ, Ao P, Boynton AL. Rapid disruption of gap junctional communication and phosphorylation of connexin43 by platelet-derived growth factor in T51B rat liver epithelial cells expressing platelet-derived growth factor receptor. J Cell Physiol 1997. [PMID: 9397157 DOI: 10.1002/(sici)1097-4652(199801)174:1<66::aid-jcp8>3.0.co;2-e] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Gap junctional communication (GJC) between contacting cells has been postulated to be involved in the regulation of cell proliferation. This suggestion stems from numerous studies showing modulation of GJC by agents that influence cellular proliferation. Platelet-derived growth factor (PDGF), a strong mitogen, inhibits GJC in many cell types. To understand the molecular nature of the signal transduction pathway responsible for the GJC blockade, T51B rat liver epithelial cells, which lack endogenous PDGF receptor (PDGFr), were infected with a retrovirus containing either wild-type full-length cDNA of human PDGFr beta (Kin+) or a mutant PDGFr beta lacking receptor tyrosine kinase activity (Kin-). PDGF caused a complete but transient interruption of cell communication in Kin+ cells within 15-20 min of addition. This interruption of GJC was not associated with a gross destabilization of gap junction plaques but with the phosphorylation of connexin43 (Cx43), the only known gap junction protein expressed in these cells. These effects were exhibited in either control T51B cells or in Kin- cells, indicating a requirement of the receptor tyrosine kinase activity. Further examination revealed that the newly phosphorylated Cx43 then undergoes a rapid degradation utilizing the lysosomal pathway resulting in a decreased total Cx43 protein level. The re-establishment of GJC following PDGF treatment was dependent on protein synthesis. This report describes a suitable cell system which is currently being utilized for the characterization of the PDGF signaling pathway responsible for the inhibition of GJC.
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Rice RL, Rusnak JM, Yokokawa F, Yokokawa S, Messner DJ, Boynton AL, Wipf P, Lazo JS. A targeted library of small-molecule, tyrosine, and dual-specificity phosphatase inhibitors derived from a rational core design and random side chain variation. Biochemistry 1997; 36:15965-74. [PMID: 9398331 DOI: 10.1021/bi971338h] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Tyrosine phosphatases (PTPases) dephosphorylate phosphotyrosines while dual-specificity phosphatases (DSPases) dephosphorylate contiguous and semicontiguous phosphothreonine and phosphotyrosine on cyclin dependent kinases and mitogen-activated protein kinases. Consequently, PTPases and DSPases have a central role controlling signal transduction and cell cycle progression. Currently, there are few readily available potent inhibitors of PTPases or DSPases other than vanadate. Using a pharmacophore modeled on natural product inhibitors of phosphothreonine phosphatases, we generated a refined library of novel, phosphate-free, small-molecule compounds synthesized by a parallel, solid-phase combinatorial-based approach. Among the initial 18 members of this targeted diversity library, we identified several inhibitors of DSPases: Cdc25A, -B, and -C and the PTPase PTP1B. These compounds at 100 microM did not significantly inhibit the protein serine/threonine phosphatases PP1 and PP2A. Kinetic studies with two members of this library indicated competitive inhibition for Cdc25 DSPases and noncompetitive inhibition for PTP1B. Compound AC-alphaalpha69 had a Ki of approximately 10 microM for recombinant human Cdc25A, -B, and -C, and a Ki of 0.85 microM for the PTP1B. The marked differences in Cdc25 inhibition as compared to PTP1B inhibition seen with relatively modest chemical modifications in the modular side chains demonstrate the structurally demanding nature of the DSPase catalytic site distinct from the PTPase catalytic site. These results represent the first fundamental advance toward a readily modifiable pharmacophore for synthetic PTPase and DSPase inhibitors and illustrate the significant potential of a combinatorial-based strategy that supplements the rational design of a core structure by a randomized variation of peripheral substituents.
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Murphy GP, Maguire RT, Rogers B, Partin AW, Nelp WB, Troychak MJ, Ragde H, Kenny GM, Barren RJ, Bowes VA, Gregorakis AK, Holmes EH, Boynton AL. Comparison of serum PSMA, PSA levels with results of Cytogen-356 ProstaScint scanning in prostatic cancer patients. Prostate 1997; 33:281-5. [PMID: 9397201 DOI: 10.1002/(sici)1097-0045(19971201)33:4<281::aid-pros9>3.0.co;2-k] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
BACKGROUND Stored serum from clinical trial cases undergoing ProstaScint (CYT-356) scanning were available for Prostate Specific Membrane Antigen (PSMA) assay. Prostate Specific Antigen (PSA) levels had already been determined. This provided an opportunity to see what correlations existed between the serum markers and the ProstaScint scan. A group of patients had the studies preprostatectomy, whereas another group had the studies postprostatectomy. METHODS The scan results, serum PSA, serum PSMA, and clinical data were separately analyzed. PSMA serum levels were determined by Western blot. RESULTS Preoperatively, radical prostatectomy patients showed a correlation between serum PSA or PSMA levels and the ProstaScint scan in the total group (n = 86), or in an untreated group (n = 38). Preoperatively, PSMA correlated with the pathological stage, whereas PSA correlated with the scan. Postoperatively, only PSMA serum levels correlated with the scan in an untreated group (n = 40). CONCLUSIONS Preoperatively or postoperatively, Western blot PSMA serum levels predict the stage of disease or local, regional, or distant metastases, as shown by ProstaScint scan. Both the scan and the serum tests provide prognostic information and evaluate the extent of disease to a more significant degree than previously possible.
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Tjoa BA, Erickson SJ, Bowes VA, Ragde H, Kenny GM, Cobb OE, Ireton RC, Troychak MJ, Boynton AL, Murphy GP. Follow-up evaluation of prostate cancer patients infused with autologous dendritic cells pulsed with PSMA peptides. Prostate 1997; 32:272-8. [PMID: 9288186 DOI: 10.1002/(sici)1097-0045(19970901)32:4<272::aid-pros7>3.0.co;2-l] [Citation(s) in RCA: 96] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
BACKGROUND We recently conducted a phase I clinical trial administering autologous dendritic cells pulsed with prostate-specific membrane antigen (PSMA) peptides to advanced prostate cancer patients. Participants were divided into 5 groups receiving 4 or 5 infusions of peptides alone (PSM-P1 or -P2; groups 1 and 2, respectively), autologous DC (group 3), or DC pulsed with PSM-P1 or -P2 (groups 4 and 5, respectively). Seven partial responders were observed. Follow-up evaluation of these responders is presented in this report. METHODS Clinical monitoring for hematological studies and prostate markers was conducted up to 370 days from the start of the phase I study. Data collected include: lymphocyte, hematocrit, alkaline phosphatase, prostate-specific antigen (PSA), free PSA, and PSMA levels. RESULTS Groups 4 and 5 (patients infused with DC pulsed with PSM-P1 or -P2) represented 5/7 responders. The length of response was between 100 days (1 patient) to 200 days or above (6 patients). Four patients still remained responsive at the end of the period of observation. CONCLUSIONS The responses observed in this phase I clinical trial are significant and of long duration. Most of the responders were in treatment groups infused with DC pulsed with PSM-P1 or -P2, suggesting the requirement of both components for effective immunotherapy.
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Swanson DA, Rothenberg HJ, Boynton AL, Consigliere D, Halling KC, Oda H, Smith D. Future prognostic factors for renal cell carcinoma: Workgroup No. 5. Union Internationale Contre le Cancer (UICC) and the American Joint Committee on Cancer (AJCC). Cancer 1997; 80:997-8. [PMID: 9307207 DOI: 10.1002/(sici)1097-0142(19970901)80:5<997::aid-cncr28>3.0.co;2-q] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
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Sehgal A, Ricks S, Keener C, Boynton AL, Young RF, Vermeulen SS, Yonemura KS, Kohler EP, Aldape HC, Simrell CR, Murphy GP. Cloning, sequence, and developmental expression analysis of C4-2, a potential brain tumor-suppressor gene. J Surg Oncol 1997; 65:249-57. [PMID: 9274789 DOI: 10.1002/(sici)1096-9098(199708)65:4<249::aid-jso5>3.0.co;2-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
BACKGROUND Previously, we reported the isolation of C4-2 as a potential tumor suppressor gene in human brain tumors. To understand the function of this gene, we investigated its molecular characterization and expression during development. METHODS Human fetal brain library screening and 5'RACE-PCR method was used to isolate the full-length cDNA. The coding region of C4-2 was used for in situ hybridization to study its expression during development. RESULTS We report here the complete sequence of this gene. Sequence analysis indicated that C4-2 has a 94% sequence identity to a family of cAMP-regulated phosphoproteins (ARPP-16/19) in the coding region. C4-2 has a 3.1 Kb long 3'UTR with variable identity to ARPP-16 and ARPP-19. Northern blot analysis indicated that C4-2 is expressed at high levels in normal brain compared to other tissues. Zoo blot analysis demonstrated that the coding region of C4-2 is highly conserved among different animals. In situ hybridization using C4-2 coding region demonstrated that it follows a unique expression pattern during mouse brain development. High level of C4-2 expression was also observed in the spinal cord and somites of the developing embryo. CONCLUSION Expression analysis during brain development strongly suggests that this family of proteins may play an important role not only in normal functioning of the brain, but also during brain development.
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Tjoa BA, Erickson SJ, Bowes VA, Salgaller ML, Lodge PA, McLean JG, Ragde H, Kenny GM, Boynton AL, Murphy GP. Cancer immunotherapy for prostate cancer. THE CANADIAN JOURNAL OF UROLOGY 1997; 4:79-82. [PMID: 12735843] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 03/02/2023]
Abstract
Our approach to prostate cancer immunotherapy involves two components dendritic cells as antigen-presenting cells; and the antigen used to target T-cell attack, HLA-A0201-associated peptides from prostate specific membrane antigen (PSMA). We have conducted a phase I dose-ranging study in 51 men with advanced prostate cancer, using dendritic cells pulsed with a PSMA peptide. no significant toxicity was observed. In that study, T-cell response was enhanced, with seven men meeting NCPC and PSA criteria for partial response. We are now conducting a phase II study with 67 men, who will receive 6 infusions of dendritic cells that have been pulsed with 2 PSMA peptides, at 6-week intervals. The phase II study design and rationale is described in this paper.
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Sehgal A, Keener C, Boynton AL, Young RF, Vermeulen SS, Yonemura KS, Kohler EP, Aldape HC, Simrell CR, Murphy GP. Isolation and characterization of a novel gene from human glioblastoma multiforme tumor tissue. Int J Cancer 1997; 71:565-72. [PMID: 9178809 DOI: 10.1002/(sici)1097-0215(19970516)71:4<565::aid-ijc10>3.0.co;2-b] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Using the technique of DD-PCR (differential display-polymerase chain reaction) we isolated a novel gene (D2-2) that is overexpressed in glioblastoma multiforme tissue (GMT) as compared to normal brain tissue (NBT). D2-2 is also highly expressed in recurrent glioma, colon tumor metastatic to brain, breast tumors, prostate tumors and a prostate tumor cell line (LNCaP). Northern blot analysis showed that D2-2 is highly expressed in several tumor cell lines (MOLT lymphoblastic leukemia, SW480 colorectal adrenocarcinoma, A549 lung carcinoma, HL-60 promyelocytic leukemia, S3 HeLa cells, K-562 chronic myelogeneous leukemia and G361 melanoma) as compared to NBT. Additionally, D2-2 is very highly expressed in cell lines derived from glioblastomas, grade IV astrocytomas, normal human fetal astrocytes (NHFA) and glioma. D2-2 is moderately expressed in neuroblastoma, neuroectodermal and medulloblastoma tumor cell lines. D2-2 expression is localized to the frontal lobe, occipital lobe and the cerebellum in the normal brain. Normal tissues such as thyroid, stomach, adrenal cortex, small intestine and pancreas show high expression of D2-2. We also show that D2-2 is expressed 28-fold higher in fetal brain (20 weeks) than in adult brain. Sequence analysis of a 2.0-kb fragment for D2-2 shows no homology to known sequences in the data base.
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Sehgal A, Keener C, Boynton AL, Young RF, Vermeulen SS, Yonemura KS, Kohler EP, Aldape HC, Simrell CR, Murphy GP. Characterization of C4-2 as a tumor-suppressor gene in human brain tumors. J Surg Oncol 1997; 64:102-8. [PMID: 9047245 DOI: 10.1002/(sici)1096-9098(199702)64:2<102::aid-jso3>3.0.co;2-f] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
BACKGROUND Brain tumors claimed the lives of 13,300 people in 1995. Our objective was to isolate and characterize unique tumor-suppressor genes from human brain tumors derived from patients in the United States. METHODS Differential display-polymerase chain reaction was used to isolate tumor suppressor genes. RESULTS Clone C4-2 was isolated and is expressed in normal adult human brain, but not in brain tissue from glioblastoma multiforme tumors. C4-2 has 66% homology to the previously isolated ARPP-16 (cAMP-regulated phosphoprotein of Mr = 16,000) based on limited sequencing. C4-2 is expressed at high levels in normal brain and is not expressed or expressed at low levels in several brain tumor cell lines. Expression of C4-2 was also either not expressed or expressed at low levels in meningioma, B-cell lymphoma, recurrent glioma, LNCAP (prostate tumor cell line), breast tumor, or prostate tumor tissue. CONCLUSION We conclude that C4-2 may function as a potential tumor-suppressor gene.
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Abstract
BACKGROUND Prostate-specific membrane antigen (PSMA) is a transmembrane glycoprotein defined by the monoclonal antibody 7E11.C5. The 7E11.C5 antibody forms the basis of an in vivo diagnostic imaging agent (ProstaScint, Cyt-356) for identification of metastatic prostate cancer. The epitope on PSMA recognized by 7E11.C5 has been determined to be the first 6 amino acids from the N-terminal, expressed on the cytoplasmic side of the plasma membrane. Thus, the basis for 7E11.C5 specificity in imaging studies remains unclear. METHODS Fluorescence-activated cell sorter (FACS) analysis of fixed and viable cultured cells was used to determine the staining intensity with FITC-labeled antibodies. RESULTS The results indicate that FITC-labeled 7E11.C5 antibody is taken up and specifically labels viable LNCaP cells in vitro. Labeling intensity of viable cells after 2 hr of antibody incubation was similar to that of fixed cells. No labeling of cells that do not express PSMA was observed, nor was labeling observed with LNCaP cells treated with an isotype-matched irrelevant antibody. CONCLUSIONS Uptake and labeling of PSMA by FITC-labeled 7E11.C5 in viable cells in vitro strongly suggest that this is a major basis for effectiveness of the 7E11.C5 antibody during in vivo imaging applications with 111In-labeled antibody (ProstaScint, Cyt-356).
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Murphy GP, Barren RJ, Erickson SJ, Bowes VA, Wolfert RL, Bartsch G, Klocker H, Pointner J, Reissigl A, McLeod DG, Douglas T, Morgan T, Kenny GM, Ragde H, Boynton AL, Holmes EH. Evaluation and comparison of two new prostate carcinoma markers. Free-prostate specific antigen and prostate specific membrane antigen. Cancer 1996; 78:809-18. [PMID: 8756376 DOI: 10.1002/(sici)1097-0142(19960815)78:4<809::aid-cncr18>3.0.co;2-z] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
BACKGROUND Two new prostate cancer markers, free-prostate specific antigen (f-PSA) and prostate specific membrane antigen (PSMA) were recently introduced. This report summarizes a prospective two-year multicenter test of their diagnostic or prognostic capabilities. Total PSA was also measured. METHODS There were four clinical groups studied: (1) 226 individuals from a screening project undergoing ultrasound and biopsy evaluation had markers obtained: (2) 68 patients suspected of having prostate cancer and undergoing 2 or more biopsies had the markers obtained on multiple occasions: (3) 100 patients undergoing radical prostatectomy had markers obtained pre- and post-operatively: and (4) 31 patients with metastatic prostate cancer each had multiple samples for marker assay obtained over a 2-year period. In all, 465 patients had one or more samples obtained and studied. RESULTS Free-PSA affords little additional diagnostic advantage compared with total PSA in the screening population. The receiver operating characteristic curves for diagnostic accuracy were ranked: (1) PSA density; (2) total PSA; (3) f-PSA; and (4) PSMA, PSMA showed the best correlation with stage of the primary tumor in the screened group. In the multiple negative biopsy group, f-PSA varied from 12 to 21%. PSMA values were evaluated in all histologic categories. PSA density was > or = 0.15 in all categories. In the prostatectomy cases PSA values postoperatively were quite low in Stage II; f-PSA was of no value. Later, f-PSA was increased in association with elevated total PSA values. Mean PSMA values were above normal in all postoperative time periods except in Stage III patients at 6 months to 1 year postoperatively. PSA densities were all > or = 0.15. In patients with metastatic carcinoma, elevated PSMA values correlated best with a poor prognosis (clinical progression), as has been described. CONCLUSIONS These data suggest that f-PSA values do not provide additional diagnostic benefit compared with total PSA in screening populations, in the presence of suspected cancer, postprostatectomy, or in metastatic disease. PSMA is of prognostic significance, especially in the presence of metastatic disease, and correlates well with the stage of disease in cancers detected in a screened population.
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Murphy GP, Tino WT, Holmes EH, Boynton AL, Erickson SJ, Bowes VA, Barren RJ, Tjoa BA, Misrock SL, Ragde H, Kenny GM. Measurement of prostate-specific membrane antigen in the serum with a new antibody. Prostate 1996; 28:266-71. [PMID: 8602402 DOI: 10.1002/(sici)1097-0045(199604)28:4<266::aid-pros7>3.0.co;2-b] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Work to date has identified prostate-specific membrane antigen (PSMA) as a membrane-bound glycoprotein with high specificity for prostatic epithelial cells. PSMA reacts with the monoclonal antibody 7E11.C5, which is present in serum, seminal fluid, and prostatic epithelial cells, and is increased in its expression in the presence of a hormone refractory state associated with prostatic cancer. This report confirms these results and further documents the presence of the monoclonal antibody 3F5.4G6, which reacts with the extracellular domain of PSMA. This region of PSMA is also an element present in a truncated version of the protein, so-called PSM'. Immune precipitation with either 7E11.C5 or 3F5.4G6 yields an isolated protein species that are reactive with the reciprocal antibody in Western blot analysis. Thus, 3F5.4G6 recognizes the same PSMA protein as does 7E11.C5, but at different epitopes on essentially opposite ends of the molecule. These two antibodies are well suited for use in a sandwich immunoassay, either one as a capture or detection antibody. Current work on this is underway. This report also confirms that 7E11.C5 Western blots for PSMA are negative with normal human brain tissue. The monoclonal antibody 9H10 does not react with 3F5.4G6 or with 7E11.C5 in studies conducted herein. Moreover, 3F5.4G6 reacts with PSMA found in the LNCaP cell line, but not DU-145 or PC3, which lack PSMA.
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Dean NM, Boynton AL. EGF-induced increase in diacylglycerol, choline release, and DNA synthesis is extracellular calcium dependent. J Cell Physiol 1995; 164:449-58. [PMID: 7650054 DOI: 10.1002/jcp.1041640302] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Previous studies have demonstrated a strict extracellular Ca2+ dependence for the G0 to G1 and G1 to S transition in growth factor-treated T51B rat liver cells that is associated with increased levels of protein kinase C activity. Consequently, we have examined these cells for changes in phospholipid-derived second messengers in response to epidermal growth factor (EGF) and thrombin in order to determine which signals are generated during the initiation of the G0 to G1 transition. Thrombin is coupled to a phosphoinositide hydrolyzing phospholipase C, as we have found a rapid Ca(2+)-independent increase in the levels of inositol 1,4,5-trisphosphate (Ins[1,4,5]P3), inositol 1,4-bisphosphate (Ins[1,4]P2), and inositol 4-monophosphate (Ins[4]P), as well as a concomitant, transient elevation in diacylglycerol. No changes in either intracellular or extracellular choline metabolites, or an increase in DNA synthesis, were found in response to thrombin. By contrast, treatment of T51B cells with EGF results in a slower, more prolonged extracellular Ca(2+)-dependent increase in both [3H]-glycerol radiolabeled diacyl-glycerol, and diacylglycerol mass, an increase in choline release into the extracellular medium, and eventually a substantial DNA synthesis. We were, however, unable to detect any changes in phosphatidylinositol (PtdIns) turnover, either by accumulation of inositol phosphates or by changes in phospholipids in response to EGF. These results indicate that DNA synthesis can readily occur in the absence of stimulated PtdIns turnover, and that PtdIns turnover is not sufficient in itself or necessary to induce DNA synthesis and is not necessary for a Ca(2+)-dependent increase in diacylglycerol. Moreover, we have demonstrated that the extracellular Ca(2+)-dependent increase in diacylglycerol levels in response to EGF is associated with an increase in extracellular choline release, which is indicative of an activation of a phosphatidylcholine-linked phospholipase D. These results suggest that diacylglycerol sources other than PtdIns's may be important in the extracellular Ca(2+)-dependent regulation of EGF-mediated cell replication.
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