Biomedical subjects

L Damstrup

Publications and source records attributed to L Damstrup.

At least 19 recordsLinked to original sources

PubMed2001

Profile of differentially expressed genes mediated by the type III epidermal growth factor receptor mutation expressed in a small-cell lung cancer cell line.

Previous studies have shown a correlation between expression of the EGF receptor type III mutation (EGFRvIII) and a more malignant phenotype of various cancers including: non-small-cell lung cancer, glioblastoma multiforme, prostate cancer and breast cancer. Thus, a detailed molecular genetic understanding of how the EGFRvIII contributes to the malignant phenotype is of major importance for future therapy. The GeneChip Hu6800Set developed by Affymetrix was used to identify changes in gene expression caused by the expression of EGFRvIII. The cell line selected for the study was an EGF receptor negative small-cell-lung cancer cell line, GLC3, stably transfected with the EGFRvIII gene in a Tet-On system. By comparison of mRNA levels in EGFRvIII-GLC3 with those of Tet-On-GLC3, it was found that the levels of mRNAs encoding several transcription factors (ATF-3, JunD, and c-Myb), cell adhesion molecules (CD36, CD24), signal transduction related molecules (MKP-1) and other molecules related to cancer (CD98, thymosin beta-10) were altered in the EGFRvIII transfected cell line. Northern hybridisations and Western blot analyses were used to verify selected results. The results indicate that expression of EGFRvIII alters expression of genes involved in the control of cell growth, survival and motility.

Blotting, Northern↗

PubMed2001

The type III epidermal growth factor receptor mutation. Biological significance and potential target for anti-cancer therapy.

Mutations in the epidermal growth factor receptor occur frequently in a number of human tumours including gliomas, non-small-cell lung carcinomas, ovarian carcinomas and prostate carcinomas. The type III epidermal growth factor receptor mutation (variously named EGFRvIII, de2-7 EGFR or AEGFR), which lacks a portion of the extracellular ligand binding domain, is the most common. Here, we review the current status with regard to the role of EGFRvIII in human cancers. A detailed discussion of the formation of EGFRvIII and its structure at the protein level are likewise included along with a discussion of its more functional roles. The design and use (preclinical and clinical) of small molecule inhibitors, antibodies, and antisense oligonucleotides against wild-type EGFR are considered in detail as these strategies can be directly adapted to target EGFRvIII. Finally, the status of EGFRvIII targeted therapy is reviewed.

Amino Acid Sequence↗

PubMed2000

Gene delivery by an epidermal growth factor/DNA polyplex to small cell lung cancer cell lines expressing low levels of epidermal growth factor receptor.

In the present study, we wanted to determine whether efficient gene delivery using an epidermal growth factor (EGF)/DNA polyplex could be accomplished in small cell lung cancer (SCLC) cell lines expressing low EGF receptor (EGFR) levels. EGFR expression levels and transduction efficiencies with polyplexes were examined in five SCLC cell lines and two controls. EGFR expression was examined by binding assays and demonstrated low EGFR levels ranging from 3.6 to 87.4 fmol/mg protein. The SCLC cell lines exhibited high sensitivity to adenovirus infection, which was an important determinant for transduction efficiency when adenovirus was used as an endosomolytic agent. The transduction efficiencies with EGF/DNA polyplexes ranged from 41% +/- 3.5% to 73% +/- 4.6% in the EGFR-positive SCLC cell lines. In the controls lacking EGFRs, only 5% +/- 1.0% and 8% +/- 1.8% of the cells were transduced. Furthermore, the transduction efficiency could be reduced from 50% +/- 4.9% to 18% +/- 1.1% when excess EGF was added to compete with the EGF/DNA polyplexes. In the present study, receptor-targeted gene delivery to SCLC cell lines has been demonstrated for the first time. Our results indicate that even low receptor expression levels in the target cells are sufficient for efficient and specific in vitro gene delivery with EGF/DNA polyplexes.

Adenoviridae↗

PubMed1999

Amphiregulin acts as an autocrine growth factor in two human polarizing colon cancer lines that exhibit domain selective EGF receptor mitogenesis.

Colonic enterocytes, like many epithelial cells in vivo, are polarized with functionally distinct apical and basolateral membrane domains. The aims of this study were to characterize the endogenous epidermal growth factor (EGF)-like ligands expressed in two polarizing colon cancer cell lines, HCA-7 Colony 29 (HCA-7) and Caco-2, and to examine the effects of cell polarity on EGF receptor-mediated mitogenesis. HCA-7 and Caco-2 cells were grown on plastic, or as a polarized monolayer on Transwell filters. Cell proliferation was measured by 3H-thymidine incorporation and EGF receptor (EGFR) binding was assessed by Scatchard analysis. EGFR ligand expression was determined by Northern blot analysis, reverse transcription polymerase chain reaction, metabolic labelling and confocal microscopy. We found that amphiregulin (AR) was the most abundant EGFR ligand expressed in HCA-7 and Caco-2 cells. AR was localized to the basolateral surface and detected in basolateral-conditioned medium. Basolateral administration of neutralizing AR antibodies significantly reduced basal DNA replication. A single class of high-affinity EGFRs was detected in the basolateral compartment, whereas the apical compartment of polarized cells, and cells cultured on plastic, displayed two classes of receptor affinity. Basolateral administration of transforming growth factor alpha (TGF-alpha) or an EGFR neutralizing antibody also resulted in a dose-dependent stimulation or attenuation, respectively, of DNA replication. However, no mitogenic response was observed when these agents were added to the apical compartment or to confluent cells cultured on plastic. We conclude that amphiregulin acts as an autocrine growth factor in HCA-7 and Caco-2 cells, and EGFR ligand-induced proliferation is influenced by cellular polarity.

Amphiregulin↗

PubMed1999

The dynamic expression of the epidermal growth factor receptor and epidermal growth factor ligand family in a differentiating intestinal epithelial cell line.

The Caco-2 intestinal epithelial cell line differentiates when cultured on plastic or permeable filters, and offers a valuable system to study events associated with enterocytic differentiation in vitro. Little is known as to whether the expression of the epidermal growth factor receptor (EGFR) and its ligands changes as intestinal epithelial cells differentiate. We found that total cellular EGFR protein and mRNA transcript levels were relatively unchanged during Caco-2 cell differentiation, but the expression of surface EGFR and patterns of steady state epidermal growth factor (EGF)-family ligand expression changed significantly. EGFR affinity, surface EGFR expression levels, and the repertoire of expressed EGF-family ligands, were different between Caco-2 cells cultured on plastic and filters. Functionally, EGFR-mediated cell proliferation and tyrosine phosphorylation of the signal transduction protein SHC could be inhibited in Caco-2 cells cultured on filters, but not on plastic. Thus, the substrate on which the cells were grown and the degree of cell differentiation strongly modulate EGFR affinity, EGFR surface expression, the steady state expression of EGF-family ligands, as well as, EGFR-mediated cellular responses. Our results suggest that the EGFR system is regulated during intestinal epithelial cell differentiation primarily at the level of ligand expression.

Amphiregulin↗

PubMed1998

High value of the radiobiological parameter Dq correlates to expression of the transforming growth factor beta type II receptor in a panel of small cell lung cancer cell lines.

Our panel of SCLC cell lines have previously been examined for their radiobiological characteristics and sensitivity to treatment with TGF beta 1. In this study we examined the possible correlations between radiobiological parameters and the expression of the TGF beta type II receptor (TGF beta-rII). We have, in other studies, shown that the presence of TGF beta-rII was mandatory for transmitting the growth inhibitory effect of TGF beta. The results showed a statistically significant difference in Dq, i.e. the shoulder width of the survival curve, between cell lines expressing TGF beta-rII and cell lines which did not express the receptor (P = 0.01). Cell lines expressing TGF beta-rII had a high Dq-value. TGF beta-rII expression did not correlate with any other radiobiological parameters. We suggest that an intact growth inhibitory pathway mediated by the TGF beta-rII may have a significant role for the repair of radiation induced DNA damage in SCLC.

Blotting, Northern↗

PubMed1998

In vitro invasion of small-cell lung cancer cell lines correlates with expression of epidermal growth factor receptor.

Formation of metastasis is a multistep process involving attachment to the basement membrane, local proteolysis and migration into surrounding tissues, lymph or bloodstream. In the present study, we have analysed the correlation between in vitro invasion and presence of the epidermal growth factor receptor (EGFR) in a panel of 21 small-cell lung cancer (SCLC) cell lines. We have previously reported that ten of these cell lines expressed EGFR protein detected by radioreceptor and affinity labelling assays. In 11 small-cell lung cancer (SCLC) cell lines, EGFR mRNA was detected by Northern blot analysis. In vitro invasion in a Boyden chamber assay was found in all EGFR-positive cell lines, whereas no invasion was detected in the EGFR-negative cell lines. Quantification of the in vitro invasion in 12 selected SCLC cell lines demonstrated that, in the EGFR-positive cell lines, between 5% and 16% of the cells added to the upper chamber were able to traverse the Matrigel membrane. Expression of several matrix metalloproteases (MMP), of tissue inhibitor of MMP (TIMP) and of cathepsin B was evaluated by immunoprecipitation, Western blot analysis and reverse transcriptase polymerase chain reaction (RT-PCR). However, in vitro invasive SCLC cell lines could not be distinguished from non-invasive cell lines based on the expression pattern of these molecules. In six SCLC cell lines, in vitro invasion was also determined in the presence of the EGFR-neutralizing monoclonal antibody mAb528. The addition of this antibody resulted in a significant reduction of the in vitro invasion in three selected EGFR-positive cell lines. Our results show that only EGFR-positive SCLC cell lines had the in vitro invasive phenotype, and it is therefore suggested that the EGFR might play an important role for the invasion potential of SCLC cell lines.

Antibodies, Monoclonal↗

PubMed1997

Epidermal growth factor receptor activation induces nuclear targeting of cyclooxygenase-2, basolateral release of prostaglandins, and mitogenesis in polarizing colon cancer cells.

Nonsteroidal antiinflammatory drugs reduce the risk of colon cancer, possibly via cyclooxygenase (COX) inhibition. The growth factor-inducible COX-2, which is overexpressed in neoplastic colonic tissue, is an attractive target to mediate this effect. Herein we have exploited the ability of a human colon cancer cell line, HCA-7 Colony 29, to polarize when cultured on Transwell (Costar) filters to study COX-2 production and the vectorial release of prostaglandins (PGs). Administration of type alpha transforming growth factor to the basolateral compartment, in which the epidermal growth factor receptor (EGFR) resides, results in a marked induction of COX-2 immunoreactivity at the base of the cells and the unexpected appearance of COX-2 in the nucleus. The increase in COX-2 protein is associated with a dose- and time-dependent increase in PG levels in the basolateral, but not apical, medium. Amphiregulin is the most abundantly expressed EGFR ligand in these cells, and the protein is present at the basolateral surface. EGFR blockade reduces baseline COX-2 immunoreactivity, PG levels, and mitogenesis in a concentration-dependent manner. Two specific COX-2 inhibitors, SC-58125 and NS 398, also, in a dose-dependent manner, attenuate baseline and type alpha transforming growth factor-stimulated mitogenesis, although PG levels are decreased > 90% at all concentrations of inhibitor tested. These findings show that activation of the EGFR stimulates COX-2 production and its translocation to the nucleus, vectorial release of PGs, and mitogenesis in polarized HCA-7 Colony 29 cells.

Amphiregulin↗

PubMed1997

Epidermal growth factor receptor (EGFR) and EGFR mutations, function and possible role in clinical trials.

The epidermal growth factor receptor (EGFR) is a growth factor receptor that induces cell differentiation and proliferation upon activation through the binding of one of its ligands. The receptor is located at the cell surface, where the binding of a ligand activates a tyrosine kinase in the intracellular region of the receptor. This tyrosine kinase phosphorylates a number of intracellular substrates that activates pathways leading to cell growth, DNA synthesis and the expression of oncogenes such as fos and jun. EGFR is thought to be involved the development of cancer, as the EGFR gene is often amplified, and/or mutated in cancer cells. In this review we will focus on: (I) the structure and function of EGFR, (II) implications of receptor/ligand coexpression and EGFR mutations or overexpression, (III) its effect on cancer cells, (IV) the development of the malignant phenotype and (V) the clinical aspects of therapeutic targeting of EGFR.

Clinical Trials as Topic↗

PubMed1996

Acquired TGF beta 1 sensitivity and TGF beta 1 expression in cell lines established from a single small cell lung cancer patient during clinical progression.

Three small cell lung cancer cell lines established from a single patient during longitudinal follow-up were examined for in vitro expression of TGF beta and TGF beta receptors, i.e. the components of an autocrine loop. GLC 14 was established prior to treatment, GLC 16 on relapse after chemotherapy and GLC 19 on recurrence after radiotherapy. TGF beta was detected by ELISA and TGF beta receptors by chemical crosslinking to radiolabelled TGF beta 1. Furthermore, TGF beta and TGF beta receptor mRNAs were detected by northern blot analysis. Expression of type II TGF beta receptor mRNA and protein was found in GLC 16 and GLC 19. These cell lines were also growth inhibited by exogenously administrated TGF beta 1. TGF beta 1 mRNA and protein in its latent form was only expressed in the radiotherapy-resistant cell line, GLC 19. The results indicate that disease progression in this patient was paralleled by a gain in sensitivity to the growth inhibition by TGF beta 1 due to type II TGF beta receptor, and a gain of latent TGF beta 1 protein. Lack of type II receptor expression in GLC 14, which was also resistant to growth inhibition by exogenous TGF beta 1, was not due to gross structural changes in the type II receptor gene, as examined by Southern blotting. Also, the type I receptor could not be detected by ligand binding assay in this cell line, despite expression of mRNA for this receptor. This agrees with previous findings that type I receptor cannot bind TGF beta 1 without co-expression of the type II receptor.

Blotting, Northern↗

PubMed1996

Transforming growth factor-alpha.

Major advances in understanding growth factor biology, especially in epithelial cells, have resulted from work with TGF-alpha over the past decade. It is clear that TGF-alpha is a potent epithelial oncoprotein, but equally important biological activities in normal epithelial homeostasis have been described. A number of major challenges lie ahead. Foremost is the formidable task of dissecting out the individual contributions of each EGF-related peptide in the biological response to stimulation of the EGFR. Appreciation of the complexity of heterodimerization of receptors within the EGFR family will be equally important in the final analysis. These considerations assure the continued vitality and productivity of investigation of the EGF-related peptide/EGFR axis.

Amino Acid Sequence↗

PubMed1995

Basic actions of transforming growth factor-alpha and related peptides.

Transforming growth factor-alpha (TGF-alpha) and related peptides have been implicated in a wide range of biological activities, including cell growth, differentiation and acid inhibition. This chapter reviews the roles of TGF-alpha in the stomach, the insights gained into the action of the TGF-alpha family of growth factors from the study of polarized epithelial cells and the confirmation of events mediated by the epidermal growth factor receptor (EGFR) by the study of mice in which the EGFR has been disrupted by homologous recombination.

Animals↗

PubMed1994

Auto- and cross-induction within the mammalian epidermal growth factor-related peptide family.

Several polypeptide growth factors related to epidermal growth factor (EGF) have been identified recently, including transforming growth factor-alpha (TGF-alpha), amphiregulin (AR), heparin-binding EGF-like growth factor (HB-EGF), and betacellulin (BTC). These peptides all bind to the EGF receptor (EGFr). In an effort to understand redundancy within this peptide family and interactions among these related peptides, we compared the biological activities of EGF, TGF-alpha, AR, and HB-EGF in an EGF-responsive, nontransformed intestinal epithelial line (RIE-1) and also determined the effect of individual EGF-related peptides on the expression of related family members in these cells. TGF-alpha, AR, HB-EGF, and EGF were equipotent in stimulating [3H]thymidine incorporation by RIE-1 cells and bound the EGFr with equivalent affinity. Each EGF-related peptide induced the mRNA expression of the remaining family members, including BTC. HB-EGF and AR mRNAs were induced rapidly (within 30 min) and to a greater extent than TGF-alpha and BTC mRNAs, suggesting heterogeneity in the molecular mechanisms for induction. This same pattern was observed for all EGF-related peptides tested. A similar pattern of mRNA induction was observed in secondary cultures of human keratinocytes and in LIM1215 colon adenocarcinoma cells. Nuclear run-on analysis showed that induction of AR and HB-EGF is, at least in part, regulated at the level of gene transcription. Concurrent treatment with HB-EGF and cycloheximide resulted in superinduction of HB-EGF and AR, suggesting that these peptides are immediate early genes in RIE-1 cells. Our results demonstrate an equivalent biological response to EGF-related peptides in RIE-1 cells and further indicate that extensive auto-induction and cross-induction occur within the EGF-related peptide family in several EGF-responsive epithelial cell types.

Amphiregulin↗

PubMed1994

Review of the curative role of radiotherapy in the treatment of non-small cell lung cancer.

The present paper is a comprehensive review of available data concerning the role of radiotherapy as an intended curative treatment in patients with non-small cell lung cancer (NSCL). The following issues are reviewed (1) optimal dose, (2) optimal fractionation, (3) optimal treatment planning, (4) clinical results in terms of single treatment and combined treatment with either surgery or chemotherapy. In resectable NSCLC high dose radiotherapy to small localized tumours gives a 5-year survival rate of 7-38%. It is concluded that this treatment modality is appropriate for certain selected patients who refuse to have surgery, who have medical contradications for surgery, or who are of old age. It is discussed whether the treatment should be split course, continuous, hypo-og hyperfraction. A total dose of 55 Gy must be given. CT scanning should be mandatory for optimal planning and therapy. The literature does not give a conclusive answer to whether preoperative or postoperative radiotherapy is indicated. The data indicate that patients with Stage III NSCLC will benefit from a combined treatment modality in terms of chemotherapy based on high dose cisplatinum and radiotherapy. The main conclusion of the review is that many areas with randomized controlled trials are needed in order to answer the critical issue of the role of radiotherapy in the treatment of NSCLS.

Carcinoma, Non-Small-Cell Lung↗

PubMed1994

Growth suppression by transforming growth factor beta 1 of human small-cell lung cancer cell lines is associated with expression of the type II receptor.

Nine human small-cell lung cancer cell lines were treated with transforming growth factor beta 1 (TGF-beta 1). Seven of the cell lines expressed receptors for transforming growth factor beta (TGF-beta-r) in different combinations between the three human subtypes I, II and III, and two were receptor negative. Growth suppression was induced by TGF-beta 1 exclusively in the five cell lines expressing the type II receptor. For the first time growth suppression by TGF-beta 1 of a cell line expressing the type II receptor without coexpression of the type I receptor is reported. No effect on growth was observed in two cell lines expressing only type III receptor and in TGF-beta-r negative cell lines. In two cell lines expressing all three receptor types, growth suppression was accompanied by morphological changes. To evaluate the possible involvement of the retinoblastoma protein (pRb) in mediating the growth-suppressive effect of TGF-beta 1, the expression of functional pRb, as characterised by nuclear localisation, was examined by immunocytochemistry. Nuclear association of pRb was only seen in two of the five TGF-beta 1-responsive cell lines. These results indicate that in SCLC pRb is not required for mediation of TGF-beta 1-induced growth suppression.

Carcinoma, Small Cell↗

PubMed1993

Expression of transforming growth factor beta (TGF beta) receptors and expression of TGF beta 1, TGF beta 2 and TGF beta 3 in human small cell lung cancer cell lines.

A panel of 21 small cell lung cancer cell (SCLC) lines were examined for the presence of Transforming growth factor beta receptors (TGF beta-r) and the expression of TGF beta mRNAs. By the radioreceptor assay we found high affinity receptors to be expressed in six cell lines. scatchard analysis of the binding data demonstrated that the cells bound between 4.5 and 27.5 fmol mg-1 protein with a KD ranging from 16 to 40 pM. TGF beta 1 binding to the receptors was confirmed by cross-linking TGF beta 1 to the TGF beta-r. Three classes of TGF beta-r were demonstrated, type I and type II receptors with M(r) = 65,000 and 90,000 and the betaglycan (type III) with M(r) = 280,000. Northern blotting showed expression of TGF beta 1 mRNA in ten, TGF beta 2 mRNA in two and TGF beta 3 mRNA in seven cell lines. Our results provide, for the first time, evidence that a large proportion of a broad panel of SCLC cell lines express TGF beta-receptors and also produce TGF beta mRNAs.

Blotting, Northern↗

PubMed1992

[Transforming growth factor beta. A potent multifunctional growth factor for normal and malignant cells].

The polypeptide growth factor transforming growth factor-beta (TGF-beta) is a multifunctional regulator of basic cellular functions: proliferation, differentiation, cell adhesion and interactions with the extracellular matrix. TGF-beta is part of a regulatory network of which our knowledge is still incomplete, together with other substances such as steroid hormones, oncogene products and integrins. Five isoforms for TGF-beta and five different TGF-beta receptors have been described. TGF-beta exhibits an antiproliferative effect in vitro and in vivo on many cells of epthelial, myeloid, lymphoid and mesenchymal origin together with a growth-stimulating effect on various cells like endothelial cells and epidermal keratinocytes. Production of TGF-beta and receptors for TGF-beta has been found in many cell types, both normal and malignant. Nevertheless the amount of in vivo data is too limited to identify possibilities for therapeutic intervention in the physiological and patophysiological functions of TGF-beta.

Breast Neoplasms↗

PubMed1992

Expression of the epidermal growth factor receptor in human small cell lung cancer cell lines.

Epidermal growth factor (EGF) receptor expression was evaluated in a panel of 21 small cell lung cancer cell lines with radioreceptor assay, affinity labeling, and Northern blotting. We found high-affinity receptors to be expressed in 10 cell lines. Scatchard analysis of the binding data demonstrated that the cells bound between 3 and 52 fmol/mg protein with a KD ranging from 0.5 x 10(-10) to 2.7 x 10(-10) M. EGF binding to the receptor was confirmed by affinity-labeling EGF to the EGF receptor. The cross-linked complex had a M(r) of 170,000-180,000. Northern blotting showed the expression of EGF receptor mRNA in all 10 cell lines that were found to be EGF receptor-positive and in one cell line that was found to be EGF receptor-negative in the radioreceptor assay and affinity labeling. Our results provide, for the first time, evidence that a large proportion of a broad panel of small cell lung cancer cell lines express the EGF receptor.

Blotting, Northern↗