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Biomedical subjects

H S Poulsen

Publications and source records attributed to H S Poulsen.

At least 19 recordsLinked to original sources
PubMed2006

The insulinoma-associated 1: a novel promoter for targeted cancer gene therapy for small-cell lung cancer.

The insulinoma-associated 1 (INSM1) gene is expressed exclusively during early embryonal development, but has been found re-expressed at high levels in neuroendocrine tumors. The regulatory region of the INSM1 gene is therefore a potential candidate for regulating expression of a therapeutic gene in transcriptionally targeted cancer gene therapy against neuroendocrine tumors. We analyzed expression of a reporter gene from a 1.7 kb region of the INSM1 promoter in a large number of small-cell lung cancer (SCLC) cell lines. This INSM1 promoter region showed very high levels of expression in most of the SCLC cell lines and expression was absent in cell lines of non-neuroendocrine origin. Inclusion of the general transcriptional enhancer from SV40 compromised the specificity of the promoter and did not enhance transcription in most of the SCLC cell lines. For comparison, the region of the gastrin releasing peptide (GRP) previously suggested for SCLC gene therapy was analyzed in a similar manner. High expression was observed for a number of cell lines, but unlike for the INSM1 promoter, reporter gene expression from the GRP promoter did not correlate to the relative GRP mRNA levels, demonstrating that this region may not contain all necessary regulatory elements. Expression of the suicide gene herpes simplex virus thymidine kinase (HSV-TK) from the INSM1 promoter in combination with treatment with the prodrug ganciclovir (GCV) caused a significant increase in GCV sensitivity specifically in INSM1-expressing cell lines. The INSM1 promoter is therefore a potential novel tool for transcriptionally targeted gene therapy for neuroendocrine tumors.

Antiviral Agents↗
PubMed2006

A prospective PET study of patients with glioblastoma multiforme.

OBJECTIVE: To study the post-surgical metabolic and structural cerebral changes in patients with glioblastoma multiforme (GBM). MATERIALS AND METHODS: We examined ten patients prospectively with newly diagnosed GBM. All patients were primarily treated with surgery, followed by chemotherapy (carmustine, cisplatine and etoposide) and radiotherapy. Positron emission tomography (PET) was used to measure tumor- and cerebral metabolism. CT or MRI was used to estimate tumor volume by measurements of tumor area. RESULTS: Tumor metabolism was not increased during chemotherapy (P = 0.71), but increased during radiotherapy (P = 0.01). CT/MRI showed similar results with no increase in tumor area during chemotherapy (P = 0.33) but increase during radiotherapy (P = 0.002). During the entire study, tumor metabolism and area increased evenly (P = 0.01). CONCLUSIONS: Our study did not show a gain of PET compared with structural imaging in the prospective evaluation of GBM. We found a difference in metabolic increase and tumor growth between the two treatment regimens, although this finding has limited relevance due to the design of the study.

Adult↗
PubMed2005

Differential response to gefitinib of cells expressing normal EGFR and the mutant EGFRvIII.

Epidermal growth factor receptor (EGFR) is frequently amplified and/or mutated in a number of human tumours and abnormal signalling from this receptor is believed to contribute to the malignant phenotype seen in these tumours. Gefitinib is a small molecule inhibitor that specifically binds and inhibits the EGFR tyrosine kinase and has been shown to inhibit the growth, proliferation, survival and invasion of a range of tumour cells overexpressing EGFR. However, clinical response to gefitinib has failed to correlate with EGFR levels and activity, indicating that other molecular mechanisms such as downstream signalling and mutations could be of importance in predicting clinical response. We therefore investigated the effect of the specific EGFR inhibitor gefitinib on the phosphorylation level, signalling and growth of cells expressing the naturally occurring constitutively active EGFR variant EGFRvIII, a low nontransforming level of EGFR and a high transforming level of EGFR. Results show that levels of gefitinib sufficient to suppress EGFR phosphorylations, EGFR-mediated proliferation and EGFR-mediated anchorage-independent growth are not sufficient to inhibit these features in cells expressing EGFRvIII. Furthermore, the data indicate that long-term exposure of EGFRvIII-expressing cells to low concentrations of gefitinib (0.01-0.1 microM) result in increased phosphotyrosine load of the receptor, increased signalling to ERK and stimulation of proliferation and anchorage-independent growth, presumably by inducing EGFRvIII dimerisation. Higher concentrations of gefitinib (1-2 microM), on the other hand, significantly decreased EGFRvIII phosphotyrosine load, EGFRvIII-mediated proliferation and anchorage-independent growth. Further studies are needed to investigate the implications of these important findings in the clinical setting.

Cell Adhesion↗
PubMed2003

Preparation and purification of cationic solid lipid nanospheres--effects on particle size, physical stability and cell toxicity.

Cationic solid lipid nanospheres (SLN) were prepared by the microemulsion technique with polysorbate 80 (Tween 80) and butanol as surfactants. The SLN (diameter 100-500 nm, zetapotential around +15 mV) consisted mainly of stearylamine (SA) and different triglycerides. Three different purification methods, ultrafiltration, ultracentrifugation and dialysis, were investigated and compared with the cellular toxicity and physical stability of the dispersions. The cell toxicity was dependent on both the SLN composition and the purification method. Dialysis was found to easily and efficiently remove excessive surfactant determined by dynamic light scattering (DLS), leading to reduced cell toxicity and increased physical stability of the SLN on storage. The cationic SLN might constitute a promising DNA delivery system.

Carcinoma, Small Cell↗
PubMed2003

A population-based study of thyroid function after radiotherapy and chemotherapy for a childhood brain tumor.

The effect of craniospinal irradiation (CSI) vs. cranial irradiation (CIR) only with or without chemotherapy (CT) on the hypothalamus/pituitary (HP) thyroid axis was assessed in a population-based study of patients treated for a childhood brain tumor not directly involving the HP axis. Thyroid function was evaluated and compared with that in healthy controls (n = 27), measuring TSH, free T4, total T4, total T3, and TRH. The biological effective dose (BED) of radiotherapy, determined for the HP region and spine and expressed in grays (Gy) as BED, gives a means of expressing the biological effects of different dosage schedules in a uniform way. Seventy-one children (45 males and 26 females), less than 15 yr of age when diagnosed between 1970-1997 in the eastern part of Denmark, were included. Twenty-nine had received CSI, and 42 had received CIR only. The median age at time of radiotherapy was 8.4 yr (range, 0.8-14.9). The median length of follow-up was 12.0 yr (range, 2.0-28.0). There was no significant difference between CSI and the CIR only patients with respect to median BED to the HP region. Primary hypothyroidism was found in 24%, of whom 71% had been treated with CSI and 29% with CIR only; 73% had compensated hypothyroidism, and 27% had overt primary hypothyroidism. Central hypothyroidism was found in 6%. Free T4 and total T3 were significantly lower in the CSI and CIR only groups compared with controls. As the CIR only group had significantly higher median basal TSH levels compared with controls and as the CSI compared with the CIR only group and controls had significantly higher median basal TSH levels, we speculate that this was probably due to scattered irradiation from both cranial and spinal fields to the thyroid gland. There was a significant relation between basal TSH and time of follow-up (r(s) = -0.39; P = 0.001). Stepwise backward multiple linear regression analysis showed that the best-fit model to predict basal TSH was free T4 (P < 0.0001), the length of follow-up (P = 0.02), and total T3 (P = 0.06). In contrast, age at radiotherapy, BED to the HP region and spine, and whether the patient had been treated with CT were not included in the model. The TRH test showed significantly exaggerated and prolonged TSH responses for the CSI and CIR only groups compared with controls, indicating HP dysfunction. In conclusion, these data suggest that both CSI and CIR for childhood brain tumor may affect the HP-thyroid axis, resulting in hypothyroidism. CT had no significant influence on HP-thyroid function. We recommend prolonged surveillance of pituitary-thyroid function in long-term survivors of childhood brain tumor and institution of thyroid hormone replacement if the levels of TSH and free T4 are above and below the normal range, respectively, to ensure normal growth and metabolism.

Adolescent↗
PubMed2003

Assessment of the hypothalamo-pituitary-adrenal axis in patients treated with radiotherapy and chemotherapy for childhood brain tumor.

The impact of cranial irradiation (CIR) and chemotherapy on the hypothalamo-pituitary (HP)-adrenal (HPA) axis was assessed in a population-based follow-up study of patients treated for childhood brain tumor not directly involving the HP axis. HPA function was evaluated and compared with that in healthy controls (n = 17), measuring basal cortisol and the peak cortisol response to an insulin tolerance test (ITT) and an ACTH test(.) The cortisol cut-off level was 500 nmol/liter. The biological effective dose (BED) of radiotherapy was determined for the HP region and spine and was expressed in Gray units, as BED gives a means of expressing the biological effects of different dosage schedules in a uniform way. Seventy-three children (46 males and 27 females), less than 15 yr of age when diagnosed during 1970-1997 in the Eastern part of Denmark, were included. The median age at time of radiotherapy was 8.4 yr (range, 0.8-14.9). The median length of follow-up was 15 yr (range, 2-29). Fourteen patients (19%) had basal cortisol levels below 500 nmol/liter and did not respond with a peak cortisol above the cut-off level to either an ACTH test (30 or 60 min) or an ITT, and thus, they had insufficiency of the HPA axis. Even though a peak cortisol above 500 nmol/liter was reached in the rest of the cohort (n = 59) after either an ACTH test (30 or 60 min) or an ITT, they had significantly lower peak cortisol levels compared with controls (P = 0.0099). Thirteen patients failed the ACTH test (30 min), but passed the ACTH test (60 min), implying a risk of misinterpreting the cortisol capacity of the patient if only the ACTH test (30 min) is obtained. The basal cortisol levels and the cortisol levels in the ACTH test (30 min) and the ACTH test (60 min) were significantly lower in the patient group compared with controls. There was a significant correlation between the peak cortisol after the ITT compared with the peak cortisol after the ACTH test (30 or 60 min; r(s) = 0.56; P = 0.0006), but 48% failed the ITT, and there was discordance in 10 of 33 (30%) patients who passed the ACTH but failed the ITT, indicating the recommendation of continuous use of the ITT as the gold standard for evaluation of the HPA axis. Stepwise backward multiple linear regression analysis showed that the best-fit model to predict the peak cortisol level after an ITT included BED (P = 0.04) and length of follow-up (P = 0.06). In contrast, age at RT, chemotherapy, BED to the spine, and gender were not included in the model. In conclusion, these data suggest that CIR for a childhood brain tumor may affect the HPA axis, resulting in secondary adrenal insufficiency, whereas adjuvant chemotherapy does not seem to add to the deleterious effect of CIR. We recommend life-long surveillance of the HPA axis and performing regular ITTs.

Adolescent↗
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

Specific killing of P53 mutated tumor cell lines by a cross-reactive human HLA-A2-restricted P53-specific CTL line.

p53 is upregulated in the majority of spontaneous tumors and the HLA class I molecule HLA-A2 is expressed by approximately 50% of the caucasians. Potentially, these facts make HLA-A2-binding p53 peptides for CTL-inducing immunotherapy applicable to a broad range of cancer patients. In our study, we investigated the CTL-inducing capacity of autologous monocyte-derived dendritic cells (DC) maturated by exposure to CD40L and pulsed with a pool of 4 wild-type, HLA-A2-binding p53 peptides, and the p53-specific CD8(+) CTL lines established from healthy HLA-A2-positive donors were characterized. Reactivity to p53(65-73) and p53(187-197) peptides was obtained in the T-cell lines. Interestingly, cold target inhibition experiments demonstrated that the simultaneous recognition of the 2 peptides was the result of cross-reactivity, which was confirmed by killing experiments at the clonal CTL level. Furthermore, 4 HLA-A2(+) p53-mutated tumor cell lines were lysed by the CTL line, indicating that these peptides are endogenously processed and presented on HLA-A2 molecule. Thus, monocyte-derived DC pulsed with a pool of peptides are able to induce CTL reactivity to wild-type p53 peptides presented by several cancer cell lines. In addition, the recognition of 2 different p53 peptides by the same CTL clone suggests a promiscuous peptide recognition by the TCR involved. Taken together, these in vitro results suggest that vaccination with autologous DC pulsed with multiple p53 epitopes may induce an effective tumor-specific CTL response in vivo with the potential to eradicate p53-upregulated spontaneously occurring tumors.

CD4-Positive T-Lymphocytes↗
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↗
PubMed2001

Gonadal status in male survivors following childhood brain tumors.

The effect of radiotherapy (RT) and chemotherapy (CT) on gonadal function was assessed in males treated for a childhood brain tumor not directly involving the hypothalamus/pituitary (HP) axis in a population-based study with a long follow-up time. All males <15 yr at the time of diagnosis (median: 9.0 yr, range: 0.8 to 14.9 yr) and diagnosed from January 1970 through February 1997 in the eastern part of Denmark and [gte]18 yr at the time of follow-up (median: 25.8 yr, range:18.5 to 39.3 yr) were included. Thirty males fulfilled the criteria. The median age at time of RT was 9.0 yr (range: 0.8 to 14.9 yr) and the median length of follow-up was 18 yr (range: 2.0 to 28.0 yr). The biological effective dose of RT was determined to the HP region and to the spine and expressed in gray because the biological effective dose gives a means of expressing the biological effect on normal tissue of different dosage schedules in a uniform way. Levels of serum FSH, luteinizing hormone (LH), sexual hormone-binding globulin, testosterone, and inhibin B were measured and compared with healthy age-matched male controls (n = 347), and the patients had a GnRH stimulation test performed with determination of peak FSH and LH. Patients treated with RT + CT (n = 13), compared with patients treated with RT only (n = 17), had significantly higher median peak FSH (8.33 vs. 3.79 IU/L, P = 0.03) and median peak LH (20.0 vs. 12.8 IU/L, P = 0.03), and significantly lower median inhibin B (86.0 vs. 270 pg/ml, P = 0.03), and median inhibin B/FSH ratio (12.8 vs. 107.9, P = 0.04), which indicates gonadal damage. Inhibin B and inhibin B/FSH ratio were also significantly lower in the RT + CT group, compared with controls (median: 86.0 vs. 215 pg/ml, P = 0.02), (median:12.8 vs. 67; P = 0.01), respectively. We found a significantly inverse correlation between basal FSH and inhibin B and FSH and total testicular volume (r(s) = -0.83; P < 0.0001), (r(s) = -0.67; P < 0.0001), respectively, and a significant correlation between inhibin B and total testicular volume (r(s) = 0.63; P < 0.0001). Stepwise backward multiple linear regression analysis showed the best-fit model to predict inhibin B levels included total testicular volume (P = 0.002) and CT (P = 0.09). Median basal LH in the RT-only group was significantly lower, compared with controls (3.44 vs. 2.45 IU/L; P = 0.0001) indicating secondary hypogonadism, and in both the RT + CT group and the RT-only group, levels of testosterone were significantly lower, compared with our reference population (12.8 vs. 21.9 nmol/L; P = 0.001, and 14.7 vs. 21.9 nmol/L; P = 0.0003), respectively. In conclusion these data suggest that cranial irradiation for a childhood brain tumor may affect the HP axis, and adjuvant CT can reduce inhibin B indicating primary gonadal damage. Thus, such patients may have normal or even low levels of FSH despite damage to the seminiferous epithelium, and because the fertility status by a semen analysis for psychological reasons can be difficult to obtain in this group of patients, we suggest inhibin B as the most useful direct serum marker of spermatogenesis in the follow-up of individuals who have received both cranial irradiation and gonadotoxic chemotherapy. However, because the number of patients with RT + CT and RT only are small, these data must be confirmed in further studies.

Adult↗
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↗
PubMed2000

Cranial radiotherapy of childhood brain tumours: growth hormone deficiency and its relation to the biological effective dose of irradiation in a large population based study.

OBJECTIVE: The study was to determine the incidence of GH deficiency (GHD) following cranial radiotherapy (RT) for a childhood brain tumour in a large population based study and analyse the biological effective dose (BED) to the hypothalamus/pituitary (HP) region as a risk factor. DESIGN: BED was assessed by use of the linear-quadratic (LQ) model, which gives a means of expressing the biological effect of various treatment schedules in a uniform way. In patients aged >/= 18 years (n = 53) GH status was assessed by an insulin-tolerance test (ITT) (n = 34), however, in patients with seizure disorders (n = 19), and in 20 children aged < 18 years GH status was assessed by an arginine test. Cut-off levels for GHD, indicating GH substitution, were defined by a peak GH response of < 9 mU/l and < 15 mU/l for patients >/= 18 and < 18 years, respectively. PATIENTS: Ninety-one children aged < 15 years eligible for the study, diagnosed between 1970 and 1997 in the Eastern part of Denmark, the Faroe Islands and Greenland, with a primary brain tumour not directly involving the HP axis. 84% (n = 76) agreed to participate. Three patients were excluded due to hypothyroidism detected at time of testing. MEASUREMENTS: Serum GH and levels of serum insulin-like growth factor-I (s-IGF-I) and serum insulin-like growth factor binding protein-3 (s-IGFBP-3) were measured. BED was assessed to the HP region. RESULTS: The median age at the time of RT was 8.7 years (range: 0.8-14.9 years) and the median time of follow-up was 15 years (range: 2-28 years). Fifty-eight patients (80%) had GHD and they had received a median BED of 77.5 Gy to the HP region, whereas the median BED was 54.5 Gy for 15 patients without GHD (P = 0.002). Peak GH and BED were correlated (rs = -0.53, P < 0001). Median IGF-I SDS and IGFBP-3 SDS were -2.5 (-5.2-0.7 SDS) and -1.7 (-5.8-0.9 SDS), respectively, and IGF-I SDS was correlated to peak GH (rs = 0.45, P < 0.001). Peak GH and length of follow-up were related (rs = -0.28, P = 0.018). Stepwise backward multiple linear regression analysis showed that the best-fit model to predict the peak GH release following ITT/arginine stimulation included BED (P < 0.0001) and length of follow-up (P = 0.05). CONCLUSIONS: The data of this study suggest that the majority of long-term survivors of brain tumours develop GH deficiency following radiotherapy in childhood and that the adverse effects of radiotherapy may be directly related to the biologically effective dose. With longer follow-up fewer patients might respond normally to GH stimulation tests.

Adolescent↗
PubMed2000

Growth hormone response to a growth hormone-releasing hormone stimulation test in a population-based study following cranial irradiation of childhood brain tumors.

Children with brain tumors are at high risk of developing growth hormone deficiency (GHD) after cranial irradiation (CI) if the hypothalamus/pituitary (HP) axis falls within the fields of irradiation. The biological effective dose (BED) of irradiation to the HP region was determined, since BED gives a means of expressing the biological effect of various irradiation treatment schedules in a uniform way. Hypothalamic versus pituitary damage as cause of GHD was distinguished in 62 patients by comparing the growth hormone (GH) peak response to an insulin tolerance test (ITT)/arginine stimulation test and the GH response to a growth hormone-releasing hormone (GHRH) stimulation test. Peak GH response to a GHRH test was significantly higher (median 7.3 mU/l; range: 0.5--79.0 mU/l) than that of an ITT/arginine test (median 4.7 mU/l; range: 0.01--75.0 mU/l) (p = 0.017). Peak GH after a GHRH test was significantly inversely correlated to follow-up time (r(s) = -0.46, p < 0.0001) and to BED (R(s) = -0.28, p = 0.03), and both were found to be of significance in a multivariante regression analysis. We speculate that a significant number of patients developed hypothalamic radiation-induced damage to the GHRH secreting neurons, and secondary to this the pituitary gland developed decreased responsiveness to GHRH following CI in childhood.

Adolescent↗
PubMed1999

Dosimetry and growth hormone deficiency following cranial irradiation of childhood brain tumors.

BACKGROUND: Dosimetry of the hypothalamus-pituitary (HP) region could allow prediction of the risk of growth hormone deficiency (GHD) following cranial irradiation. PROCEDURE: Nineteen children (15 boys) with a median age of 6.3 years (range 1.7-16.5) at the time of irradiation of a brain tumor not involving the HP axis were followed for 1.2-6.3 years (median 3.4) from radiotherapy (RT). The dose to a standardized anatomical model including the HP region was calculated from dose-volume histograms of 10% to 100% in steps of 10% of the HP model based on data from a computer-based treatment planning system. If GHD was suspected from insulin-like growth factor-I, serum insulin-like growth factor binding protein-3, and/or height velocity measurements, an arginine stimulation test was performed. GHD was defined by a peak GH <15mU/liter. RESULTS: Ten patients developed GHD 10-26 months from irradiation. Cox regression analysis identified the 90% dose-volume of the HP box as the strongest predictor of development of GHD (P = 0.03). The median dose to the 90% dose-volume of the HP region was 37.5 Gy (range 2. 3-55.3). The cumulated risk of GHD 2.5 years after radiotherapy for children receiving more than and less than 37.5 Gy to the HP region was 87% and 33%, respectively (P = 0.036). CONCLUSIONS: Dosimetry of a defined HP volume provides the opportunity to 1) calculate the exact dose delivered to this region, 2) predict the risk of GHD and, 3) in the future revise the treatment planning and thus reduce the risk of endocrine adverse effects.

Adolescent↗
PubMed1999

Gene therapy for lung cancer.

In the pre-clinical research into the development of gene therapy for cancer, different strategies have evolved and shown promising results in the laboratory. However, most of these strategies will need further refinement to obtain clinical success. This is partly due to the lack of suitable vector systems which specifically can deliver the therapeutic gene to the target cells, and ensure expression of the therapeutic gene. In this review we will give an introduction to different strategies used in cancer gene therapy for neoplasms of the lung, and focus on how to target gene delivery to disseminated lung cancer cells. Tumor specific gene expression can be accomplished at different levels. One way to accomplish targeted gene delivery is by coupling of receptor specific ligands to the vector. Specific gene delivery to cells expressing the target receptor will occur by receptor mediated endocytosis of the vector. Further restriction of gene expression to cancer cells can be accomplished by utilizing promoters predominantly active in tumors. When gene therapy is targeted at different levels, efficient gene delivery to disseminated cancer cells by systemic vector administration will be an attractive future prospect.

Animals↗
PubMed1999

Treatment of newly diagnosed glioblastoma multiforme with carmustine, cisplatin and etoposide followed by radiotherapy. A phase II study.

A meta-analysis and several studies of patients with grade III and IV gliomas have indicated that the addition of nitrosurea based chemotherapy to surgery and radiation may improve survival. We performed a phase II study of pre-irradiative chemotherapy with BCNU, cisplatin and etoposide. This implies a short total treatment duration and a reliable response evaluation. The treatment schedule was three cycles of BCNU 200 mg/m2 i.v. on day 1, cisplatin 20 mg/m2 i.v. on day 1-5 and etoposide (VP-16) 100 mg/m2 i.v. on day 1-5, given every five weeks and followed by localized radiation, 60 Gy in 30 fractions. Twenty-nine patients with newly diagnosed glioblastoma multiforme (GBM), mean age 50 (27-66) and performance status (PS) 0-2 were included. Using the Macdonald criteria 33% had partial remission (PR), 41% stable disease (SD) and 26% progressive disease (PD) after chemotherapy. After additional radiation 44% had PR, 37% SD and 19% PD. Non-hematological toxicity and leukopenia was mild, but thrombocytopenia (TP) frequent. Grade III and IV TP occurred in 25% and 57% respectively, and grade III bleeding in 45%. No severe or fatal complications was seen. Median time to progression (TTP) was 7.6 months (6.0-9.1) and median survival was 11.4 months (10.1-12.7). We conclude that this regimen is effective and feasible in patients with GBM. The short course pre-irradiatory chemotherapy may be less cumbersome than adjuvant chemotherapy and the regimen may be even more active in grade III gliomas.

Adult↗
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↗